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freebsd-skq/sys/kern/uipc_shm.c

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Add a new file descriptor type for IPC shared memory objects and use it to implement shm_open(2) and shm_unlink(2) in the kernel: - Each shared memory file descriptor is associated with a swap-backed vm object which provides the backing store. Each descriptor starts off with a size of zero, but the size can be altered via ftruncate(2). The shared memory file descriptors also support fstat(2). read(2), write(2), ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared memory file descriptors. - shm_open(2) and shm_unlink(2) are now implemented as system calls that manage shared memory file descriptors. The virtual namespace that maps pathnames to shared memory file descriptors is implemented as a hash table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash of the pathname. - As an extension, the constant 'SHM_ANON' may be specified in place of the path argument to shm_open(2). In this case, an unnamed shared memory file descriptor will be created similar to the IPC_PRIVATE key for shmget(2). Note that the shared memory object can still be shared among processes by sharing the file descriptor via fork(2) or sendmsg(2), but it is unnamed. This effectively serves to implement the getmemfd() idea bandied about the lists several times over the years. - The backing store for shared memory file descriptors are garbage collected when they are not referenced by any open file descriptors or the shm_open(2) virtual namespace. Submitted by: dillon, peter (previous versions) Submitted by: rwatson (I based this on his version) Reviewed by: alc (suggested converting getmemfd() to shm_open())
2008-01-08 21:58:16 +00:00
/*-
Correct several issues in the integration of POSIX shared memory objects and the new setmode and setowner fileops in FreeBSD 9.0: - Add new MAC Framework entry point mac_posixshm_check_create() to allow MAC policies to authorise shared memory use. Provide a stub policy and test policy templates. - Add missing Biba and MLS implementations of mac_posixshm_check_setmode() and mac_posixshm_check_setowner(). - Add 'accmode' argument to mac_posixshm_check_open() -- unlike the mac_posixsem_check_open() entry point it was modeled on, the access mode is required as shared memory access can be read-only as well as writable; this isn't true of POSIX semaphores. - Implement full range of POSIX shared memory entry points for Biba and MLS. Sponsored by: Google Inc. Obtained from: TrustedBSD Project Approved by: re (kib)
2011-09-02 17:40:39 +00:00
* Copyright (c) 2006, 2011 Robert N. M. Watson
Add a new file descriptor type for IPC shared memory objects and use it to implement shm_open(2) and shm_unlink(2) in the kernel: - Each shared memory file descriptor is associated with a swap-backed vm object which provides the backing store. Each descriptor starts off with a size of zero, but the size can be altered via ftruncate(2). The shared memory file descriptors also support fstat(2). read(2), write(2), ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared memory file descriptors. - shm_open(2) and shm_unlink(2) are now implemented as system calls that manage shared memory file descriptors. The virtual namespace that maps pathnames to shared memory file descriptors is implemented as a hash table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash of the pathname. - As an extension, the constant 'SHM_ANON' may be specified in place of the path argument to shm_open(2). In this case, an unnamed shared memory file descriptor will be created similar to the IPC_PRIVATE key for shmget(2). Note that the shared memory object can still be shared among processes by sharing the file descriptor via fork(2) or sendmsg(2), but it is unnamed. This effectively serves to implement the getmemfd() idea bandied about the lists several times over the years. - The backing store for shared memory file descriptors are garbage collected when they are not referenced by any open file descriptors or the shm_open(2) virtual namespace. Submitted by: dillon, peter (previous versions) Submitted by: rwatson (I based this on his version) Reviewed by: alc (suggested converting getmemfd() to shm_open())
2008-01-08 21:58:16 +00:00
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
/*
* Support for shared swap-backed anonymous memory objects via
* shm_open(2) and shm_unlink(2). While most of the implementation is
* here, vm_mmap.c contains mapping logic changes.
*
* TODO:
*
Correct several issues in the integration of POSIX shared memory objects and the new setmode and setowner fileops in FreeBSD 9.0: - Add new MAC Framework entry point mac_posixshm_check_create() to allow MAC policies to authorise shared memory use. Provide a stub policy and test policy templates. - Add missing Biba and MLS implementations of mac_posixshm_check_setmode() and mac_posixshm_check_setowner(). - Add 'accmode' argument to mac_posixshm_check_open() -- unlike the mac_posixsem_check_open() entry point it was modeled on, the access mode is required as shared memory access can be read-only as well as writable; this isn't true of POSIX semaphores. - Implement full range of POSIX shared memory entry points for Biba and MLS. Sponsored by: Google Inc. Obtained from: TrustedBSD Project Approved by: re (kib)
2011-09-02 17:40:39 +00:00
* (1) Need to export data to a userland tool via a sysctl. Should ipcs(1)
Add a new file descriptor type for IPC shared memory objects and use it to implement shm_open(2) and shm_unlink(2) in the kernel: - Each shared memory file descriptor is associated with a swap-backed vm object which provides the backing store. Each descriptor starts off with a size of zero, but the size can be altered via ftruncate(2). The shared memory file descriptors also support fstat(2). read(2), write(2), ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared memory file descriptors. - shm_open(2) and shm_unlink(2) are now implemented as system calls that manage shared memory file descriptors. The virtual namespace that maps pathnames to shared memory file descriptors is implemented as a hash table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash of the pathname. - As an extension, the constant 'SHM_ANON' may be specified in place of the path argument to shm_open(2). In this case, an unnamed shared memory file descriptor will be created similar to the IPC_PRIVATE key for shmget(2). Note that the shared memory object can still be shared among processes by sharing the file descriptor via fork(2) or sendmsg(2), but it is unnamed. This effectively serves to implement the getmemfd() idea bandied about the lists several times over the years. - The backing store for shared memory file descriptors are garbage collected when they are not referenced by any open file descriptors or the shm_open(2) virtual namespace. Submitted by: dillon, peter (previous versions) Submitted by: rwatson (I based this on his version) Reviewed by: alc (suggested converting getmemfd() to shm_open())
2008-01-08 21:58:16 +00:00
* and ipcrm(1) be expanded or should new tools to manage both POSIX
* kernel semaphores and POSIX shared memory be written?
*
Correct several issues in the integration of POSIX shared memory objects and the new setmode and setowner fileops in FreeBSD 9.0: - Add new MAC Framework entry point mac_posixshm_check_create() to allow MAC policies to authorise shared memory use. Provide a stub policy and test policy templates. - Add missing Biba and MLS implementations of mac_posixshm_check_setmode() and mac_posixshm_check_setowner(). - Add 'accmode' argument to mac_posixshm_check_open() -- unlike the mac_posixsem_check_open() entry point it was modeled on, the access mode is required as shared memory access can be read-only as well as writable; this isn't true of POSIX semaphores. - Implement full range of POSIX shared memory entry points for Biba and MLS. Sponsored by: Google Inc. Obtained from: TrustedBSD Project Approved by: re (kib)
2011-09-02 17:40:39 +00:00
* (2) Add support for this file type to fstat(1).
Add a new file descriptor type for IPC shared memory objects and use it to implement shm_open(2) and shm_unlink(2) in the kernel: - Each shared memory file descriptor is associated with a swap-backed vm object which provides the backing store. Each descriptor starts off with a size of zero, but the size can be altered via ftruncate(2). The shared memory file descriptors also support fstat(2). read(2), write(2), ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared memory file descriptors. - shm_open(2) and shm_unlink(2) are now implemented as system calls that manage shared memory file descriptors. The virtual namespace that maps pathnames to shared memory file descriptors is implemented as a hash table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash of the pathname. - As an extension, the constant 'SHM_ANON' may be specified in place of the path argument to shm_open(2). In this case, an unnamed shared memory file descriptor will be created similar to the IPC_PRIVATE key for shmget(2). Note that the shared memory object can still be shared among processes by sharing the file descriptor via fork(2) or sendmsg(2), but it is unnamed. This effectively serves to implement the getmemfd() idea bandied about the lists several times over the years. - The backing store for shared memory file descriptors are garbage collected when they are not referenced by any open file descriptors or the shm_open(2) virtual namespace. Submitted by: dillon, peter (previous versions) Submitted by: rwatson (I based this on his version) Reviewed by: alc (suggested converting getmemfd() to shm_open())
2008-01-08 21:58:16 +00:00
*
Correct several issues in the integration of POSIX shared memory objects and the new setmode and setowner fileops in FreeBSD 9.0: - Add new MAC Framework entry point mac_posixshm_check_create() to allow MAC policies to authorise shared memory use. Provide a stub policy and test policy templates. - Add missing Biba and MLS implementations of mac_posixshm_check_setmode() and mac_posixshm_check_setowner(). - Add 'accmode' argument to mac_posixshm_check_open() -- unlike the mac_posixsem_check_open() entry point it was modeled on, the access mode is required as shared memory access can be read-only as well as writable; this isn't true of POSIX semaphores. - Implement full range of POSIX shared memory entry points for Biba and MLS. Sponsored by: Google Inc. Obtained from: TrustedBSD Project Approved by: re (kib)
2011-09-02 17:40:39 +00:00
* (3) Resource limits? Does this need its own resource limits or are the
Add a new file descriptor type for IPC shared memory objects and use it to implement shm_open(2) and shm_unlink(2) in the kernel: - Each shared memory file descriptor is associated with a swap-backed vm object which provides the backing store. Each descriptor starts off with a size of zero, but the size can be altered via ftruncate(2). The shared memory file descriptors also support fstat(2). read(2), write(2), ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared memory file descriptors. - shm_open(2) and shm_unlink(2) are now implemented as system calls that manage shared memory file descriptors. The virtual namespace that maps pathnames to shared memory file descriptors is implemented as a hash table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash of the pathname. - As an extension, the constant 'SHM_ANON' may be specified in place of the path argument to shm_open(2). In this case, an unnamed shared memory file descriptor will be created similar to the IPC_PRIVATE key for shmget(2). Note that the shared memory object can still be shared among processes by sharing the file descriptor via fork(2) or sendmsg(2), but it is unnamed. This effectively serves to implement the getmemfd() idea bandied about the lists several times over the years. - The backing store for shared memory file descriptors are garbage collected when they are not referenced by any open file descriptors or the shm_open(2) virtual namespace. Submitted by: dillon, peter (previous versions) Submitted by: rwatson (I based this on his version) Reviewed by: alc (suggested converting getmemfd() to shm_open())
2008-01-08 21:58:16 +00:00
* existing limits in mmap(2) sufficient?
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
Add some checks to ensure that Capsicum is behaving correctly, and add some more explicit comments about what's going on and what future maintainers need to do when e.g. adding a new operation to a sys_machdep.c. Approved by: mentor(rwatson), re(bz)
2011-06-30 10:56:02 +00:00
#include "opt_capsicum.h"
In the shm_open() and shm_unlink() syscalls, export the path to KTR. MFC after: 1 week
2014-08-01 23:29:04 +00:00
#include "opt_ktrace.h"
Add some checks to ensure that Capsicum is behaving correctly, and add some more explicit comments about what's going on and what future maintainers need to do when e.g. adding a new operation to a sys_machdep.c. Approved by: mentor(rwatson), re(bz)
2011-06-30 10:56:02 +00:00
Add a new file descriptor type for IPC shared memory objects and use it to implement shm_open(2) and shm_unlink(2) in the kernel: - Each shared memory file descriptor is associated with a swap-backed vm object which provides the backing store. Each descriptor starts off with a size of zero, but the size can be altered via ftruncate(2). The shared memory file descriptors also support fstat(2). read(2), write(2), ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared memory file descriptors. - shm_open(2) and shm_unlink(2) are now implemented as system calls that manage shared memory file descriptors. The virtual namespace that maps pathnames to shared memory file descriptors is implemented as a hash table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash of the pathname. - As an extension, the constant 'SHM_ANON' may be specified in place of the path argument to shm_open(2). In this case, an unnamed shared memory file descriptor will be created similar to the IPC_PRIVATE key for shmget(2). Note that the shared memory object can still be shared among processes by sharing the file descriptor via fork(2) or sendmsg(2), but it is unnamed. This effectively serves to implement the getmemfd() idea bandied about the lists several times over the years. - The backing store for shared memory file descriptors are garbage collected when they are not referenced by any open file descriptors or the shm_open(2) virtual namespace. Submitted by: dillon, peter (previous versions) Submitted by: rwatson (I based this on his version) Reviewed by: alc (suggested converting getmemfd() to shm_open())
2008-01-08 21:58:16 +00:00
#include <sys/param.h>
Update kernel inclusions of capability.h to use capsicum.h instead; some further refinement is required as some device drivers intended to be portable over FreeBSD versions rely on __FreeBSD_version to decide whether to include capability.h. MFC after: 3 weeks
2014-03-16 10:55:57 +00:00
#include <sys/capsicum.h>
Use a unit number allocator to provide suitable st_dev and st_ino values for POSIX shared memory descriptors. The implementation is similar to that used for pipes. MFC after: 1 week
2014-08-29 18:18:29 +00:00
#include <sys/conf.h>
Add a new file descriptor type for IPC shared memory objects and use it to implement shm_open(2) and shm_unlink(2) in the kernel: - Each shared memory file descriptor is associated with a swap-backed vm object which provides the backing store. Each descriptor starts off with a size of zero, but the size can be altered via ftruncate(2). The shared memory file descriptors also support fstat(2). read(2), write(2), ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared memory file descriptors. - shm_open(2) and shm_unlink(2) are now implemented as system calls that manage shared memory file descriptors. The virtual namespace that maps pathnames to shared memory file descriptors is implemented as a hash table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash of the pathname. - As an extension, the constant 'SHM_ANON' may be specified in place of the path argument to shm_open(2). In this case, an unnamed shared memory file descriptor will be created similar to the IPC_PRIVATE key for shmget(2). Note that the shared memory object can still be shared among processes by sharing the file descriptor via fork(2) or sendmsg(2), but it is unnamed. This effectively serves to implement the getmemfd() idea bandied about the lists several times over the years. - The backing store for shared memory file descriptors are garbage collected when they are not referenced by any open file descriptors or the shm_open(2) virtual namespace. Submitted by: dillon, peter (previous versions) Submitted by: rwatson (I based this on his version) Reviewed by: alc (suggested converting getmemfd() to shm_open())
2008-01-08 21:58:16 +00:00
#include <sys/fcntl.h>
#include <sys/file.h>
#include <sys/filedesc.h>
#include <sys/fnv_hash.h>
#include <sys/kernel.h>
In the shm_open() and shm_unlink() syscalls, export the path to KTR. MFC after: 1 week
2014-08-01 23:29:04 +00:00
#include <sys/uio.h>
#include <sys/signal.h>
#include <sys/ktrace.h>
Add a new file descriptor type for IPC shared memory objects and use it to implement shm_open(2) and shm_unlink(2) in the kernel: - Each shared memory file descriptor is associated with a swap-backed vm object which provides the backing store. Each descriptor starts off with a size of zero, but the size can be altered via ftruncate(2). The shared memory file descriptors also support fstat(2). read(2), write(2), ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared memory file descriptors. - shm_open(2) and shm_unlink(2) are now implemented as system calls that manage shared memory file descriptors. The virtual namespace that maps pathnames to shared memory file descriptors is implemented as a hash table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash of the pathname. - As an extension, the constant 'SHM_ANON' may be specified in place of the path argument to shm_open(2). In this case, an unnamed shared memory file descriptor will be created similar to the IPC_PRIVATE key for shmget(2). Note that the shared memory object can still be shared among processes by sharing the file descriptor via fork(2) or sendmsg(2), but it is unnamed. This effectively serves to implement the getmemfd() idea bandied about the lists several times over the years. - The backing store for shared memory file descriptors are garbage collected when they are not referenced by any open file descriptors or the shm_open(2) virtual namespace. Submitted by: dillon, peter (previous versions) Submitted by: rwatson (I based this on his version) Reviewed by: alc (suggested converting getmemfd() to shm_open())
2008-01-08 21:58:16 +00:00
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mman.h>
#include <sys/mutex.h>
Add the fo_chown and fo_chmod methods to struct fileops and use them to implement fchown(2) and fchmod(2) support for several file types that previously lacked it. Add MAC entries for chown/chmod done on posix shared memory and (old) in-kernel posix semaphores. Based on the submission by: glebius Reviewed by: rwatson Approved by: re (bz)
2011-08-16 20:07:47 +00:00
#include <sys/priv.h>
Add a new file descriptor type for IPC shared memory objects and use it to implement shm_open(2) and shm_unlink(2) in the kernel: - Each shared memory file descriptor is associated with a swap-backed vm object which provides the backing store. Each descriptor starts off with a size of zero, but the size can be altered via ftruncate(2). The shared memory file descriptors also support fstat(2). read(2), write(2), ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared memory file descriptors. - shm_open(2) and shm_unlink(2) are now implemented as system calls that manage shared memory file descriptors. The virtual namespace that maps pathnames to shared memory file descriptors is implemented as a hash table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash of the pathname. - As an extension, the constant 'SHM_ANON' may be specified in place of the path argument to shm_open(2). In this case, an unnamed shared memory file descriptor will be created similar to the IPC_PRIVATE key for shmget(2). Note that the shared memory object can still be shared among processes by sharing the file descriptor via fork(2) or sendmsg(2), but it is unnamed. This effectively serves to implement the getmemfd() idea bandied about the lists several times over the years. - The backing store for shared memory file descriptors are garbage collected when they are not referenced by any open file descriptors or the shm_open(2) virtual namespace. Submitted by: dillon, peter (previous versions) Submitted by: rwatson (I based this on his version) Reviewed by: alc (suggested converting getmemfd() to shm_open())
2008-01-08 21:58:16 +00:00
#include <sys/proc.h>
#include <sys/refcount.h>
#include <sys/resourcevar.h>
Switch vm_object lock to be a rwlock. * VM_OBJECT_LOCK and VM_OBJECT_UNLOCK are mapped to write operations * VM_OBJECT_SLEEP() is introduced as a general purpose primitve to get a sleep operation using a VM_OBJECT_LOCK() as protection * The approach must bear with vm_pager.h namespace pollution so many files require including directly rwlock.h
2013-02-20 10:38:34 +00:00
#include <sys/rwlock.h>
Add a new file descriptor type for IPC shared memory objects and use it to implement shm_open(2) and shm_unlink(2) in the kernel: - Each shared memory file descriptor is associated with a swap-backed vm object which provides the backing store. Each descriptor starts off with a size of zero, but the size can be altered via ftruncate(2). The shared memory file descriptors also support fstat(2). read(2), write(2), ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared memory file descriptors. - shm_open(2) and shm_unlink(2) are now implemented as system calls that manage shared memory file descriptors. The virtual namespace that maps pathnames to shared memory file descriptors is implemented as a hash table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash of the pathname. - As an extension, the constant 'SHM_ANON' may be specified in place of the path argument to shm_open(2). In this case, an unnamed shared memory file descriptor will be created similar to the IPC_PRIVATE key for shmget(2). Note that the shared memory object can still be shared among processes by sharing the file descriptor via fork(2) or sendmsg(2), but it is unnamed. This effectively serves to implement the getmemfd() idea bandied about the lists several times over the years. - The backing store for shared memory file descriptors are garbage collected when they are not referenced by any open file descriptors or the shm_open(2) virtual namespace. Submitted by: dillon, peter (previous versions) Submitted by: rwatson (I based this on his version) Reviewed by: alc (suggested converting getmemfd() to shm_open())
2008-01-08 21:58:16 +00:00
#include <sys/stat.h>
Add kern_shm_open(). This allows you to specify the capabilities that the new file descriptor should have. This allows us to create shared memory objects that only have the rights we're interested in. The idea behind restricting the rights is that it makes it a lot easier for CloudABI to get consistent behaviour across different operating systems. We only need to make sure that a shared memory implementation consistently implements the operations that are whitelisted. Approved by: kib Obtained from: https://github.com/NuxiNL/freebsd
2015-08-01 07:21:14 +00:00
#include <sys/syscallsubr.h>
Add a new file descriptor type for IPC shared memory objects and use it to implement shm_open(2) and shm_unlink(2) in the kernel: - Each shared memory file descriptor is associated with a swap-backed vm object which provides the backing store. Each descriptor starts off with a size of zero, but the size can be altered via ftruncate(2). The shared memory file descriptors also support fstat(2). read(2), write(2), ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared memory file descriptors. - shm_open(2) and shm_unlink(2) are now implemented as system calls that manage shared memory file descriptors. The virtual namespace that maps pathnames to shared memory file descriptors is implemented as a hash table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash of the pathname. - As an extension, the constant 'SHM_ANON' may be specified in place of the path argument to shm_open(2). In this case, an unnamed shared memory file descriptor will be created similar to the IPC_PRIVATE key for shmget(2). Note that the shared memory object can still be shared among processes by sharing the file descriptor via fork(2) or sendmsg(2), but it is unnamed. This effectively serves to implement the getmemfd() idea bandied about the lists several times over the years. - The backing store for shared memory file descriptors are garbage collected when they are not referenced by any open file descriptors or the shm_open(2) virtual namespace. Submitted by: dillon, peter (previous versions) Submitted by: rwatson (I based this on his version) Reviewed by: alc (suggested converting getmemfd() to shm_open())
2008-01-08 21:58:16 +00:00
#include <sys/sysctl.h>
#include <sys/sysproto.h>
#include <sys/systm.h>
#include <sys/sx.h>
#include <sys/time.h>
#include <sys/vnode.h>
Implement read(2)/write(2) and neccessary lseek(2) for posix shmfd. Add MAC framework entries for posix shm read and write. Do not allow implicit extension of the underlying memory segment past the limit set by ftruncate(2) by either of the syscalls. Read and write returns short i/o, lseek(2) fails with EINVAL when resulting offset does not fit into the limit. Discussed with: alc Tested by: pho Sponsored by: The FreeBSD Foundation
2013-08-21 17:45:00 +00:00
#include <sys/unistd.h>
Add a new fo_fill_kinfo fileops method to add type-specific information to struct kinfo_file. - Move the various fill_*_info() methods out of kern_descrip.c and into the various file type implementations. - Rework the support for kinfo_ofile to generate a suitable kinfo_file object for each file and then convert that to a kinfo_ofile structure rather than keeping a second, different set of code that directly manipulates type-specific file information. - Remove the shm_path() and ksem_info() layering violations. Differential Revision: https://reviews.freebsd.org/D775 Reviewed by: kib, glebius (earlier version)
2014-09-22 16:20:47 +00:00
#include <sys/user.h>
Add a new file descriptor type for IPC shared memory objects and use it to implement shm_open(2) and shm_unlink(2) in the kernel: - Each shared memory file descriptor is associated with a swap-backed vm object which provides the backing store. Each descriptor starts off with a size of zero, but the size can be altered via ftruncate(2). The shared memory file descriptors also support fstat(2). read(2), write(2), ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared memory file descriptors. - shm_open(2) and shm_unlink(2) are now implemented as system calls that manage shared memory file descriptors. The virtual namespace that maps pathnames to shared memory file descriptors is implemented as a hash table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash of the pathname. - As an extension, the constant 'SHM_ANON' may be specified in place of the path argument to shm_open(2). In this case, an unnamed shared memory file descriptor will be created similar to the IPC_PRIVATE key for shmget(2). Note that the shared memory object can still be shared among processes by sharing the file descriptor via fork(2) or sendmsg(2), but it is unnamed. This effectively serves to implement the getmemfd() idea bandied about the lists several times over the years. - The backing store for shared memory file descriptors are garbage collected when they are not referenced by any open file descriptors or the shm_open(2) virtual namespace. Submitted by: dillon, peter (previous versions) Submitted by: rwatson (I based this on his version) Reviewed by: alc (suggested converting getmemfd() to shm_open())
2008-01-08 21:58:16 +00:00
#include <security/mac/mac_framework.h>
#include <vm/vm.h>
#include <vm/vm_param.h>
#include <vm/pmap.h>
Use vm_mmap_to_errno(). Submitted by: kib
2011-12-15 15:17:19 +00:00
#include <vm/vm_extern.h>
Add a new file descriptor type for IPC shared memory objects and use it to implement shm_open(2) and shm_unlink(2) in the kernel: - Each shared memory file descriptor is associated with a swap-backed vm object which provides the backing store. Each descriptor starts off with a size of zero, but the size can be altered via ftruncate(2). The shared memory file descriptors also support fstat(2). read(2), write(2), ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared memory file descriptors. - shm_open(2) and shm_unlink(2) are now implemented as system calls that manage shared memory file descriptors. The virtual namespace that maps pathnames to shared memory file descriptors is implemented as a hash table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash of the pathname. - As an extension, the constant 'SHM_ANON' may be specified in place of the path argument to shm_open(2). In this case, an unnamed shared memory file descriptor will be created similar to the IPC_PRIVATE key for shmget(2). Note that the shared memory object can still be shared among processes by sharing the file descriptor via fork(2) or sendmsg(2), but it is unnamed. This effectively serves to implement the getmemfd() idea bandied about the lists several times over the years. - The backing store for shared memory file descriptors are garbage collected when they are not referenced by any open file descriptors or the shm_open(2) virtual namespace. Submitted by: dillon, peter (previous versions) Submitted by: rwatson (I based this on his version) Reviewed by: alc (suggested converting getmemfd() to shm_open())
2008-01-08 21:58:16 +00:00
#include <vm/vm_map.h>
Add a helper API to allow in-kernel code to map portions of shared memory objects created by shm_open(2) into the kernel's address space. This provides a convenient way for creating shared memory buffers between userland and the kernel without requiring custom character devices.
2011-12-14 22:22:19 +00:00
#include <vm/vm_kern.h>
Add a new file descriptor type for IPC shared memory objects and use it to implement shm_open(2) and shm_unlink(2) in the kernel: - Each shared memory file descriptor is associated with a swap-backed vm object which provides the backing store. Each descriptor starts off with a size of zero, but the size can be altered via ftruncate(2). The shared memory file descriptors also support fstat(2). read(2), write(2), ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared memory file descriptors. - shm_open(2) and shm_unlink(2) are now implemented as system calls that manage shared memory file descriptors. The virtual namespace that maps pathnames to shared memory file descriptors is implemented as a hash table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash of the pathname. - As an extension, the constant 'SHM_ANON' may be specified in place of the path argument to shm_open(2). In this case, an unnamed shared memory file descriptor will be created similar to the IPC_PRIVATE key for shmget(2). Note that the shared memory object can still be shared among processes by sharing the file descriptor via fork(2) or sendmsg(2), but it is unnamed. This effectively serves to implement the getmemfd() idea bandied about the lists several times over the years. - The backing store for shared memory file descriptors are garbage collected when they are not referenced by any open file descriptors or the shm_open(2) virtual namespace. Submitted by: dillon, peter (previous versions) Submitted by: rwatson (I based this on his version) Reviewed by: alc (suggested converting getmemfd() to shm_open())
2008-01-08 21:58:16 +00:00
#include <vm/vm_object.h>
#include <vm/vm_page.h>
Correct an error of omission in the implementation of the truncation operation on POSIX shared memory objects and tmpfs. Previously, neither of these modules correctly handled the case in which the new size of the object or file was not a multiple of the page size. Specifically, they did not handle partial page truncation of data stored on swap. As a result, stale data might later be returned to an application. Interestingly, a data inconsistency was less likely to occur under tmpfs than POSIX shared memory objects. The reason being that a different mistake by the tmpfs truncation operation helped avoid a data inconsistency. If the data was still resident in memory in a PG_CACHED page, then the tmpfs truncation operation would reactivate that page, zero the truncated portion, and leave the page pinned in memory. More precisely, the benevolent error was that the truncation operation didn't add the reactivated page to any of the paging queues, effectively pinning the page. This page would remain pinned until the file was destroyed or the page was read or written. With this change, the page is now added to the inactive queue. Discussed with: jhb Reviewed by: kib (an earlier version) MFC after: 3 weeks
2012-01-08 20:09:26 +00:00
#include <vm/vm_pageout.h>
Add a new file descriptor type for IPC shared memory objects and use it to implement shm_open(2) and shm_unlink(2) in the kernel: - Each shared memory file descriptor is associated with a swap-backed vm object which provides the backing store. Each descriptor starts off with a size of zero, but the size can be altered via ftruncate(2). The shared memory file descriptors also support fstat(2). read(2), write(2), ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared memory file descriptors. - shm_open(2) and shm_unlink(2) are now implemented as system calls that manage shared memory file descriptors. The virtual namespace that maps pathnames to shared memory file descriptors is implemented as a hash table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash of the pathname. - As an extension, the constant 'SHM_ANON' may be specified in place of the path argument to shm_open(2). In this case, an unnamed shared memory file descriptor will be created similar to the IPC_PRIVATE key for shmget(2). Note that the shared memory object can still be shared among processes by sharing the file descriptor via fork(2) or sendmsg(2), but it is unnamed. This effectively serves to implement the getmemfd() idea bandied about the lists several times over the years. - The backing store for shared memory file descriptors are garbage collected when they are not referenced by any open file descriptors or the shm_open(2) virtual namespace. Submitted by: dillon, peter (previous versions) Submitted by: rwatson (I based this on his version) Reviewed by: alc (suggested converting getmemfd() to shm_open())
2008-01-08 21:58:16 +00:00
#include <vm/vm_pager.h>
#include <vm/swap_pager.h>
struct shm_mapping {
char *sm_path;
Fnv32_t sm_fnv;
struct shmfd *sm_shmfd;
LIST_ENTRY(shm_mapping) sm_link;
};
static MALLOC_DEFINE(M_SHMFD, "shmfd", "shared memory file descriptor");
static LIST_HEAD(, shm_mapping) *shm_dictionary;
static struct sx shm_dict_lock;
static struct mtx shm_timestamp_lock;
static u_long shm_hash;
Use a unit number allocator to provide suitable st_dev and st_ino values for POSIX shared memory descriptors. The implementation is similar to that used for pipes. MFC after: 1 week
2014-08-29 18:18:29 +00:00
static struct unrhdr *shm_ino_unr;
static dev_t shm_dev_ino;
Add a new file descriptor type for IPC shared memory objects and use it to implement shm_open(2) and shm_unlink(2) in the kernel: - Each shared memory file descriptor is associated with a swap-backed vm object which provides the backing store. Each descriptor starts off with a size of zero, but the size can be altered via ftruncate(2). The shared memory file descriptors also support fstat(2). read(2), write(2), ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared memory file descriptors. - shm_open(2) and shm_unlink(2) are now implemented as system calls that manage shared memory file descriptors. The virtual namespace that maps pathnames to shared memory file descriptors is implemented as a hash table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash of the pathname. - As an extension, the constant 'SHM_ANON' may be specified in place of the path argument to shm_open(2). In this case, an unnamed shared memory file descriptor will be created similar to the IPC_PRIVATE key for shmget(2). Note that the shared memory object can still be shared among processes by sharing the file descriptor via fork(2) or sendmsg(2), but it is unnamed. This effectively serves to implement the getmemfd() idea bandied about the lists several times over the years. - The backing store for shared memory file descriptors are garbage collected when they are not referenced by any open file descriptors or the shm_open(2) virtual namespace. Submitted by: dillon, peter (previous versions) Submitted by: rwatson (I based this on his version) Reviewed by: alc (suggested converting getmemfd() to shm_open())
2008-01-08 21:58:16 +00:00
#define SHM_HASH(fnv) (&shm_dictionary[(fnv) & shm_hash])
static int shm_access(struct shmfd *shmfd, struct ucred *ucred, int flags);
static struct shmfd *shm_alloc(struct ucred *ucred, mode_t mode);
Rename shm_dict_init to shm_init to fix a compiler warning. Reviewed by: jhb
2014-08-29 21:50:32 +00:00
static void shm_init(void *arg);
Add a new file descriptor type for IPC shared memory objects and use it to implement shm_open(2) and shm_unlink(2) in the kernel: - Each shared memory file descriptor is associated with a swap-backed vm object which provides the backing store. Each descriptor starts off with a size of zero, but the size can be altered via ftruncate(2). The shared memory file descriptors also support fstat(2). read(2), write(2), ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared memory file descriptors. - shm_open(2) and shm_unlink(2) are now implemented as system calls that manage shared memory file descriptors. The virtual namespace that maps pathnames to shared memory file descriptors is implemented as a hash table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash of the pathname. - As an extension, the constant 'SHM_ANON' may be specified in place of the path argument to shm_open(2). In this case, an unnamed shared memory file descriptor will be created similar to the IPC_PRIVATE key for shmget(2). Note that the shared memory object can still be shared among processes by sharing the file descriptor via fork(2) or sendmsg(2), but it is unnamed. This effectively serves to implement the getmemfd() idea bandied about the lists several times over the years. - The backing store for shared memory file descriptors are garbage collected when they are not referenced by any open file descriptors or the shm_open(2) virtual namespace. Submitted by: dillon, peter (previous versions) Submitted by: rwatson (I based this on his version) Reviewed by: alc (suggested converting getmemfd() to shm_open())
2008-01-08 21:58:16 +00:00
static void shm_drop(struct shmfd *shmfd);
static struct shmfd *shm_hold(struct shmfd *shmfd);
static void shm_insert(char *path, Fnv32_t fnv, struct shmfd *shmfd);
static struct shmfd *shm_lookup(char *path, Fnv32_t fnv);
static int shm_remove(char *path, Fnv32_t fnv, struct ucred *ucred);
Implement global and per-uid accounting of the anonymous memory. Add rlimit RLIMIT_SWAP that limits the amount of swap that may be reserved for the uid. The accounting information (charge) is associated with either map entry, or vm object backing the entry, assuming the object is the first one in the shadow chain and entry does not require COW. Charge is moved from entry to object on allocation of the object, e.g. during the mmap, assuming the object is allocated, or on the first page fault on the entry. It moves back to the entry on forks due to COW setup. The per-entry granularity of accounting makes the charge process fair for processes that change uid during lifetime, and decrements charge for proper uid when region is unmapped. The interface of vm_pager_allocate(9) is extended by adding struct ucred *, that is used to charge appropriate uid when allocation if performed by kernel, e.g. md(4). Several syscalls, among them is fork(2), may now return ENOMEM when global or per-uid limits are enforced. In collaboration with: pho Reviewed by: alc Approved by: re (kensmith)
2009-06-23 20:45:22 +00:00
static int shm_dotruncate(struct shmfd *shmfd, off_t length);
Add a new file descriptor type for IPC shared memory objects and use it to implement shm_open(2) and shm_unlink(2) in the kernel: - Each shared memory file descriptor is associated with a swap-backed vm object which provides the backing store. Each descriptor starts off with a size of zero, but the size can be altered via ftruncate(2). The shared memory file descriptors also support fstat(2). read(2), write(2), ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared memory file descriptors. - shm_open(2) and shm_unlink(2) are now implemented as system calls that manage shared memory file descriptors. The virtual namespace that maps pathnames to shared memory file descriptors is implemented as a hash table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash of the pathname. - As an extension, the constant 'SHM_ANON' may be specified in place of the path argument to shm_open(2). In this case, an unnamed shared memory file descriptor will be created similar to the IPC_PRIVATE key for shmget(2). Note that the shared memory object can still be shared among processes by sharing the file descriptor via fork(2) or sendmsg(2), but it is unnamed. This effectively serves to implement the getmemfd() idea bandied about the lists several times over the years. - The backing store for shared memory file descriptors are garbage collected when they are not referenced by any open file descriptors or the shm_open(2) virtual namespace. Submitted by: dillon, peter (previous versions) Submitted by: rwatson (I based this on his version) Reviewed by: alc (suggested converting getmemfd() to shm_open())
2008-01-08 21:58:16 +00:00
static fo_rdwr_t shm_read;
static fo_rdwr_t shm_write;
static fo_truncate_t shm_truncate;
static fo_stat_t shm_stat;
static fo_close_t shm_close;
Add the fo_chown and fo_chmod methods to struct fileops and use them to implement fchown(2) and fchmod(2) support for several file types that previously lacked it. Add MAC entries for chown/chmod done on posix shared memory and (old) in-kernel posix semaphores. Based on the submission by: glebius Reviewed by: rwatson Approved by: re (bz)
2011-08-16 20:07:47 +00:00
static fo_chmod_t shm_chmod;
static fo_chown_t shm_chown;
Implement read(2)/write(2) and neccessary lseek(2) for posix shmfd. Add MAC framework entries for posix shm read and write. Do not allow implicit extension of the underlying memory segment past the limit set by ftruncate(2) by either of the syscalls. Read and write returns short i/o, lseek(2) fails with EINVAL when resulting offset does not fit into the limit. Discussed with: alc Tested by: pho Sponsored by: The FreeBSD Foundation
2013-08-21 17:45:00 +00:00
static fo_seek_t shm_seek;
Add a new fo_fill_kinfo fileops method to add type-specific information to struct kinfo_file. - Move the various fill_*_info() methods out of kern_descrip.c and into the various file type implementations. - Rework the support for kinfo_ofile to generate a suitable kinfo_file object for each file and then convert that to a kinfo_ofile structure rather than keeping a second, different set of code that directly manipulates type-specific file information. - Remove the shm_path() and ksem_info() layering violations. Differential Revision: https://reviews.freebsd.org/D775 Reviewed by: kib, glebius (earlier version)
2014-09-22 16:20:47 +00:00
static fo_fill_kinfo_t shm_fill_kinfo;
Add a new file operations hook for mmap operations. File type-specific logic is now placed in the mmap hook implementation rather than requiring it to be placed in sys/vm/vm_mmap.c. This hook allows new file types to support mmap() as well as potentially allowing mmap() for existing file types that do not currently support any mapping. The vm_mmap() function is now split up into two functions. A new vm_mmap_object() function handles the "back half" of vm_mmap() and accepts a referenced VM object to map rather than a (handle, handle_type) tuple. vm_mmap() is now reduced to converting a (handle, handle_type) tuple to a a VM object and then calling vm_mmap_object() to handle the actual mapping. The vm_mmap() function remains for use by other parts of the kernel (e.g. device drivers and exec) but now only supports mapping vnodes, character devices, and anonymous memory. The mmap() system call invokes vm_mmap_object() directly with a NULL object for anonymous mappings. For mappings using a file descriptor, the descriptors fo_mmap() hook is invoked instead. The fo_mmap() hook is responsible for performing type-specific checks and adjustments to arguments as well as possibly modifying mapping parameters such as flags or the object offset. The fo_mmap() hook routines then call vm_mmap_object() to handle the actual mapping. The fo_mmap() hook is optional. If it is not set, then fo_mmap() will fail with ENODEV. A fo_mmap() hook is implemented for regular files, character devices, and shared memory objects (created via shm_open()). While here, consistently use the VM_PROT_* constants for the vm_prot_t type for the 'prot' variable passed to vm_mmap() and vm_mmap_object() as well as the vm_mmap_vnode() and vm_mmap_cdev() helper routines. Previously some places were using the mmap()-specific PROT_* constants instead. While this happens to work because PROT_xx == VM_PROT_xx, using VM_PROT_* is more correct. Differential Revision: https://reviews.freebsd.org/D2658 Reviewed by: alc (glanced over), kib MFC after: 1 month Sponsored by: Chelsio
2015-06-04 19:41:15 +00:00
static fo_mmap_t shm_mmap;
Add a new file descriptor type for IPC shared memory objects and use it to implement shm_open(2) and shm_unlink(2) in the kernel: - Each shared memory file descriptor is associated with a swap-backed vm object which provides the backing store. Each descriptor starts off with a size of zero, but the size can be altered via ftruncate(2). The shared memory file descriptors also support fstat(2). read(2), write(2), ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared memory file descriptors. - shm_open(2) and shm_unlink(2) are now implemented as system calls that manage shared memory file descriptors. The virtual namespace that maps pathnames to shared memory file descriptors is implemented as a hash table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash of the pathname. - As an extension, the constant 'SHM_ANON' may be specified in place of the path argument to shm_open(2). In this case, an unnamed shared memory file descriptor will be created similar to the IPC_PRIVATE key for shmget(2). Note that the shared memory object can still be shared among processes by sharing the file descriptor via fork(2) or sendmsg(2), but it is unnamed. This effectively serves to implement the getmemfd() idea bandied about the lists several times over the years. - The backing store for shared memory file descriptors are garbage collected when they are not referenced by any open file descriptors or the shm_open(2) virtual namespace. Submitted by: dillon, peter (previous versions) Submitted by: rwatson (I based this on his version) Reviewed by: alc (suggested converting getmemfd() to shm_open())
2008-01-08 21:58:16 +00:00
/* File descriptor operations. */
static struct fileops shm_ops = {
.fo_read = shm_read,
.fo_write = shm_write,
.fo_truncate = shm_truncate,
Fix various issues with invalid file operations: - Add invfo_rdwr() (for read and write), invfo_ioctl(), invfo_poll(), and invfo_kqfilter() for use by file types that do not support the respective operations. Home-grown versions of invfo_poll() were universally broken (they returned an errno value, invfo_poll() uses poll_no_poll() to return an appropriate event mask). Home-grown ioctl routines also tended to return an incorrect errno (invfo_ioctl returns ENOTTY). - Use the invfo_*() functions instead of local versions for unsupported file operations. - Reorder fileops members to match the order in the structure definition to make it easier to spot missing members. - Add several missing methods to linuxfileops used by the OFED shim layer: fo_write(), fo_truncate(), fo_kqfilter(), and fo_stat(). Most of these used invfo_*(), but a dummy fo_stat() implementation was added.
2014-09-12 21:29:10 +00:00
.fo_ioctl = invfo_ioctl,
.fo_poll = invfo_poll,
.fo_kqfilter = invfo_kqfilter,
Add a new file descriptor type for IPC shared memory objects and use it to implement shm_open(2) and shm_unlink(2) in the kernel: - Each shared memory file descriptor is associated with a swap-backed vm object which provides the backing store. Each descriptor starts off with a size of zero, but the size can be altered via ftruncate(2). The shared memory file descriptors also support fstat(2). read(2), write(2), ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared memory file descriptors. - shm_open(2) and shm_unlink(2) are now implemented as system calls that manage shared memory file descriptors. The virtual namespace that maps pathnames to shared memory file descriptors is implemented as a hash table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash of the pathname. - As an extension, the constant 'SHM_ANON' may be specified in place of the path argument to shm_open(2). In this case, an unnamed shared memory file descriptor will be created similar to the IPC_PRIVATE key for shmget(2). Note that the shared memory object can still be shared among processes by sharing the file descriptor via fork(2) or sendmsg(2), but it is unnamed. This effectively serves to implement the getmemfd() idea bandied about the lists several times over the years. - The backing store for shared memory file descriptors are garbage collected when they are not referenced by any open file descriptors or the shm_open(2) virtual namespace. Submitted by: dillon, peter (previous versions) Submitted by: rwatson (I based this on his version) Reviewed by: alc (suggested converting getmemfd() to shm_open())
2008-01-08 21:58:16 +00:00
.fo_stat = shm_stat,
.fo_close = shm_close,
Add the fo_chown and fo_chmod methods to struct fileops and use them to implement fchown(2) and fchmod(2) support for several file types that previously lacked it. Add MAC entries for chown/chmod done on posix shared memory and (old) in-kernel posix semaphores. Based on the submission by: glebius Reviewed by: rwatson Approved by: re (bz)
2011-08-16 20:07:47 +00:00
.fo_chmod = shm_chmod,
.fo_chown = shm_chown,
Implement sendfile(2) for the posix shared memory segment file descriptor, in addition to the regular files. Requested by: alc Discussed with: emaste Tested by: pho (previous version) Sponsored by: The FreeBSD Foundation Approved by: re (hrs)
2013-09-11 06:41:15 +00:00
.fo_sendfile = vn_sendfile,
Implement read(2)/write(2) and neccessary lseek(2) for posix shmfd. Add MAC framework entries for posix shm read and write. Do not allow implicit extension of the underlying memory segment past the limit set by ftruncate(2) by either of the syscalls. Read and write returns short i/o, lseek(2) fails with EINVAL when resulting offset does not fit into the limit. Discussed with: alc Tested by: pho Sponsored by: The FreeBSD Foundation
2013-08-21 17:45:00 +00:00
.fo_seek = shm_seek,
Add a new fo_fill_kinfo fileops method to add type-specific information to struct kinfo_file. - Move the various fill_*_info() methods out of kern_descrip.c and into the various file type implementations. - Rework the support for kinfo_ofile to generate a suitable kinfo_file object for each file and then convert that to a kinfo_ofile structure rather than keeping a second, different set of code that directly manipulates type-specific file information. - Remove the shm_path() and ksem_info() layering violations. Differential Revision: https://reviews.freebsd.org/D775 Reviewed by: kib, glebius (earlier version)
2014-09-22 16:20:47 +00:00
.fo_fill_kinfo = shm_fill_kinfo,
Add a new file operations hook for mmap operations. File type-specific logic is now placed in the mmap hook implementation rather than requiring it to be placed in sys/vm/vm_mmap.c. This hook allows new file types to support mmap() as well as potentially allowing mmap() for existing file types that do not currently support any mapping. The vm_mmap() function is now split up into two functions. A new vm_mmap_object() function handles the "back half" of vm_mmap() and accepts a referenced VM object to map rather than a (handle, handle_type) tuple. vm_mmap() is now reduced to converting a (handle, handle_type) tuple to a a VM object and then calling vm_mmap_object() to handle the actual mapping. The vm_mmap() function remains for use by other parts of the kernel (e.g. device drivers and exec) but now only supports mapping vnodes, character devices, and anonymous memory. The mmap() system call invokes vm_mmap_object() directly with a NULL object for anonymous mappings. For mappings using a file descriptor, the descriptors fo_mmap() hook is invoked instead. The fo_mmap() hook is responsible for performing type-specific checks and adjustments to arguments as well as possibly modifying mapping parameters such as flags or the object offset. The fo_mmap() hook routines then call vm_mmap_object() to handle the actual mapping. The fo_mmap() hook is optional. If it is not set, then fo_mmap() will fail with ENODEV. A fo_mmap() hook is implemented for regular files, character devices, and shared memory objects (created via shm_open()). While here, consistently use the VM_PROT_* constants for the vm_prot_t type for the 'prot' variable passed to vm_mmap() and vm_mmap_object() as well as the vm_mmap_vnode() and vm_mmap_cdev() helper routines. Previously some places were using the mmap()-specific PROT_* constants instead. While this happens to work because PROT_xx == VM_PROT_xx, using VM_PROT_* is more correct. Differential Revision: https://reviews.freebsd.org/D2658 Reviewed by: alc (glanced over), kib MFC after: 1 month Sponsored by: Chelsio
2015-06-04 19:41:15 +00:00
.fo_mmap = shm_mmap,
Implement read(2)/write(2) and neccessary lseek(2) for posix shmfd. Add MAC framework entries for posix shm read and write. Do not allow implicit extension of the underlying memory segment past the limit set by ftruncate(2) by either of the syscalls. Read and write returns short i/o, lseek(2) fails with EINVAL when resulting offset does not fit into the limit. Discussed with: alc Tested by: pho Sponsored by: The FreeBSD Foundation
2013-08-21 17:45:00 +00:00
.fo_flags = DFLAG_PASSABLE | DFLAG_SEEKABLE
Add a new file descriptor type for IPC shared memory objects and use it to implement shm_open(2) and shm_unlink(2) in the kernel: - Each shared memory file descriptor is associated with a swap-backed vm object which provides the backing store. Each descriptor starts off with a size of zero, but the size can be altered via ftruncate(2). The shared memory file descriptors also support fstat(2). read(2), write(2), ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared memory file descriptors. - shm_open(2) and shm_unlink(2) are now implemented as system calls that manage shared memory file descriptors. The virtual namespace that maps pathnames to shared memory file descriptors is implemented as a hash table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash of the pathname. - As an extension, the constant 'SHM_ANON' may be specified in place of the path argument to shm_open(2). In this case, an unnamed shared memory file descriptor will be created similar to the IPC_PRIVATE key for shmget(2). Note that the shared memory object can still be shared among processes by sharing the file descriptor via fork(2) or sendmsg(2), but it is unnamed. This effectively serves to implement the getmemfd() idea bandied about the lists several times over the years. - The backing store for shared memory file descriptors are garbage collected when they are not referenced by any open file descriptors or the shm_open(2) virtual namespace. Submitted by: dillon, peter (previous versions) Submitted by: rwatson (I based this on his version) Reviewed by: alc (suggested converting getmemfd() to shm_open())
2008-01-08 21:58:16 +00:00
};
FEATURE(posix_shm, "POSIX shared memory");
Extract the general-purpose code from tmpfs to perform uiomove from the page queue of some vm object. Discussed with: alc Tested by: pho Sponsored by: The FreeBSD Foundation
2013-08-21 17:23:24 +00:00
static int
uiomove_object_page(vm_object_t obj, size_t len, struct uio *uio)
{
vm_page_t m;
vm_pindex_t idx;
size_t tlen;
int error, offset, rv;
idx = OFF_TO_IDX(uio->uio_offset);
offset = uio->uio_offset & PAGE_MASK;
tlen = MIN(PAGE_SIZE - offset, len);
VM_OBJECT_WLOCK(obj);
uiomove_object_page(): Avoid instantiating pages in sparse regions on reads. Check whether the page being requested is either resident or on swap. If not, read from the zero_region instead of instantiating an unnecessary page. This avoids consuming memory for sparse files on tmpfs, when they are read by applications that do not use SEEK_HOLE/SEEK_DATA (which is most of them). Reviewed by: kib MFC after: 1 week Sponsored by: Spectra Logic
2015-04-11 18:51:41 +00:00
/*
* Read I/O without either a corresponding resident page or swap
* page: use zero_region. This is intended to avoid instantiating
* pages on read from a sparse region.
*/
if (uio->uio_rw == UIO_READ && vm_page_lookup(obj, idx) == NULL &&
!vm_pager_has_page(obj, idx, NULL, NULL)) {
VM_OBJECT_WUNLOCK(obj);
Use correct length for sparse uiomove(). It must be the clipped to the page size, len is the total transfer length, which may be larger than zero_region. Reported and tested by: clusteradm (gjb) Sponsored by: The FreeBSD Foundation X-MFC-With: r281442
2015-04-24 22:05:12 +00:00
return (uiomove(__DECONST(void *, zero_region), tlen, uio));
uiomove_object_page(): Avoid instantiating pages in sparse regions on reads. Check whether the page being requested is either resident or on swap. If not, read from the zero_region instead of instantiating an unnecessary page. This avoids consuming memory for sparse files on tmpfs, when they are read by applications that do not use SEEK_HOLE/SEEK_DATA (which is most of them). Reviewed by: kib MFC after: 1 week Sponsored by: Spectra Logic
2015-04-11 18:51:41 +00:00
}
Extract the general-purpose code from tmpfs to perform uiomove from the page queue of some vm object. Discussed with: alc Tested by: pho Sponsored by: The FreeBSD Foundation
2013-08-21 17:23:24 +00:00
/*
* Parallel reads of the page content from disk are prevented
* by exclusive busy.
*
* Although the tmpfs vnode lock is held here, it is
* nonetheless safe to sleep waiting for a free page. The
* pageout daemon does not need to acquire the tmpfs vnode
* lock to page out tobj's pages because tobj is a OBJT_SWAP
* type object.
*/
Remove the deprecated VM_ALLOC_RETRY flag for the vm_page_grab(9). The flag was mandatory since r209792, where vm_page_grab(9) was changed to only support the alloc retry semantic. Suggested and reviewed by: alc Sponsored by: The FreeBSD Foundation
2013-08-22 07:39:53 +00:00
m = vm_page_grab(obj, idx, VM_ALLOC_NORMAL);
Extract the general-purpose code from tmpfs to perform uiomove from the page queue of some vm object. Discussed with: alc Tested by: pho Sponsored by: The FreeBSD Foundation
2013-08-21 17:23:24 +00:00
if (m->valid != VM_PAGE_BITS_ALL) {
if (vm_pager_has_page(obj, idx, NULL, NULL)) {
A change to KPI of vm_pager_get_pages() and underlying VOP_GETPAGES(). o With new KPI consumers can request contiguous ranges of pages, and unlike before, all pages will be kept busied on return, like it was done before with the 'reqpage' only. Now the reqpage goes away. With new interface it is easier to implement code protected from race conditions. Such arrayed requests for now should be preceeded by a call to vm_pager_haspage() to make sure that request is possible. This could be improved later, making vm_pager_haspage() obsolete. Strenghtening the promises on the business of the array of pages allows us to remove such hacks as swp_pager_free_nrpage() and vm_pager_free_nonreq(). o New KPI accepts two integer pointers that may optionally point at values for read ahead and read behind, that a pager may do, if it can. These pages are completely owned by pager, and not controlled by the caller. This shifts the UFS-specific readahead logic from vm_fault.c, which should be file system agnostic, into vnode_pager.c. It also removes one VOP_BMAP() request per hard fault. Discussed with: kib, alc, jeff, scottl Sponsored by: Nginx, Inc. Sponsored by: Netflix
2015-12-16 21:30:45 +00:00
rv = vm_pager_get_pages(obj, &m, 1, NULL, NULL);
Extract the general-purpose code from tmpfs to perform uiomove from the page queue of some vm object. Discussed with: alc Tested by: pho Sponsored by: The FreeBSD Foundation
2013-08-21 17:23:24 +00:00
if (rv != VM_PAGER_OK) {
printf(
"uiomove_object: vm_obj %p idx %jd valid %x pager error %d\n",
obj, idx, m->valid, rv);
vm_page_lock(m);
vm_page_free(m);
vm_page_unlock(m);
VM_OBJECT_WUNLOCK(obj);
return (EIO);
}
} else
vm_page_zero_invalid(m, TRUE);
}
vm_page_xunbusy(m);
vm_page_lock(m);
vm_page_hold(m);
If vm_page_grab() allocates a new page, the page is not inserted into page queue even when the allocation is not wired. It is responsibility of the vm_page_grab() caller to ensure that the page does not end on the vm_object queue but not on the pagedaemon queue, which would effectively create unpageable unwired page. In exec_map_first_page() and vm_imgact_hold_page(), activate the page immediately after unbusying it, to avoid leak. In the uiomove_object_page(), deactivate page before the object is unlocked. There is no leak, since the page is deactivated after uiomove_fromphys() finished. But allowing non-queued non-wired page in the unlocked object queue makes it impossible to assert that leak does not happen in other places. Reviewed by: alc Sponsored by: The FreeBSD Foundation MFC after: 1 week
2014-08-13 05:44:08 +00:00
if (m->queue == PQ_NONE) {
vm_page_deactivate(m);
} else {
/* Requeue to maintain LRU ordering. */
vm_page_requeue(m);
}
Extract the general-purpose code from tmpfs to perform uiomove from the page queue of some vm object. Discussed with: alc Tested by: pho Sponsored by: The FreeBSD Foundation
2013-08-21 17:23:24 +00:00
vm_page_unlock(m);
VM_OBJECT_WUNLOCK(obj);
error = uiomove_fromphys(&m, offset, tlen, uio);
if (uio->uio_rw == UIO_WRITE && error == 0) {
VM_OBJECT_WLOCK(obj);
vm_page_dirty(m);
For md(4), posix shm(3) and tmpfs(5), free swap space used by paged in dirty page, which is written by the process. Reviewed by: alc Tested by: pho Sponsored by: The FreeBSD Foundation MFC after: 1 week
2014-07-28 14:27:05 +00:00
vm_pager_page_unswapped(m);
Extract the general-purpose code from tmpfs to perform uiomove from the page queue of some vm object. Discussed with: alc Tested by: pho Sponsored by: The FreeBSD Foundation
2013-08-21 17:23:24 +00:00
VM_OBJECT_WUNLOCK(obj);
}
vm_page_lock(m);
vm_page_unhold(m);
vm_page_unlock(m);
return (error);
}
int
uiomove_object(vm_object_t obj, off_t obj_size, struct uio *uio)
{
ssize_t resid;
size_t len;
int error;
error = 0;
while ((resid = uio->uio_resid) > 0) {
if (obj_size <= uio->uio_offset)
break;
len = MIN(obj_size - uio->uio_offset, resid);
if (len == 0)
break;
error = uiomove_object_page(obj, len, uio);
if (error != 0 || resid == uio->uio_resid)
break;
}
return (error);
}
Implement read(2)/write(2) and neccessary lseek(2) for posix shmfd. Add MAC framework entries for posix shm read and write. Do not allow implicit extension of the underlying memory segment past the limit set by ftruncate(2) by either of the syscalls. Read and write returns short i/o, lseek(2) fails with EINVAL when resulting offset does not fit into the limit. Discussed with: alc Tested by: pho Sponsored by: The FreeBSD Foundation
2013-08-21 17:45:00 +00:00
static int
shm_seek(struct file *fp, off_t offset, int whence, struct thread *td)
{
struct shmfd *shmfd;
off_t foffset;
int error;
shmfd = fp->f_data;
foffset = foffset_lock(fp, 0);
error = 0;
switch (whence) {
case L_INCR:
if (foffset < 0 ||
(offset > 0 && foffset > OFF_MAX - offset)) {
error = EOVERFLOW;
break;
}
offset += foffset;
break;
case L_XTND:
if (offset > 0 && shmfd->shm_size > OFF_MAX - offset) {
error = EOVERFLOW;
break;
}
offset += shmfd->shm_size;
break;
case L_SET:
break;
default:
error = EINVAL;
}
if (error == 0) {
if (offset < 0 || offset > shmfd->shm_size)
error = EINVAL;
else
change td_retval into a union w/ off_t, with defines to mask the change... This eliminates a cast, and also forces td_retval (often 2 32-bit registers) to be aligned so that off_t's can be stored there on arches with strict alignment requirements like armeb (AVILA)... On i386, this doesn't change alignment, and on amd64 it doesn't either, as register_t is already 64bits... This will also prevent future breakage due to people adding additional fields to the struct... This gets AVILA booting a bit farther... Reviewed by: bde
2014-03-16 00:53:40 +00:00
td->td_uretoff.tdu_off = offset;
Implement read(2)/write(2) and neccessary lseek(2) for posix shmfd. Add MAC framework entries for posix shm read and write. Do not allow implicit extension of the underlying memory segment past the limit set by ftruncate(2) by either of the syscalls. Read and write returns short i/o, lseek(2) fails with EINVAL when resulting offset does not fit into the limit. Discussed with: alc Tested by: pho Sponsored by: The FreeBSD Foundation
2013-08-21 17:45:00 +00:00
}
foffset_unlock(fp, offset, error != 0 ? FOF_NOUPDATE : 0);
return (error);
}
Add a new file descriptor type for IPC shared memory objects and use it to implement shm_open(2) and shm_unlink(2) in the kernel: - Each shared memory file descriptor is associated with a swap-backed vm object which provides the backing store. Each descriptor starts off with a size of zero, but the size can be altered via ftruncate(2). The shared memory file descriptors also support fstat(2). read(2), write(2), ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared memory file descriptors. - shm_open(2) and shm_unlink(2) are now implemented as system calls that manage shared memory file descriptors. The virtual namespace that maps pathnames to shared memory file descriptors is implemented as a hash table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash of the pathname. - As an extension, the constant 'SHM_ANON' may be specified in place of the path argument to shm_open(2). In this case, an unnamed shared memory file descriptor will be created similar to the IPC_PRIVATE key for shmget(2). Note that the shared memory object can still be shared among processes by sharing the file descriptor via fork(2) or sendmsg(2), but it is unnamed. This effectively serves to implement the getmemfd() idea bandied about the lists several times over the years. - The backing store for shared memory file descriptors are garbage collected when they are not referenced by any open file descriptors or the shm_open(2) virtual namespace. Submitted by: dillon, peter (previous versions) Submitted by: rwatson (I based this on his version) Reviewed by: alc (suggested converting getmemfd() to shm_open())
2008-01-08 21:58:16 +00:00
static int
shm_read(struct file *fp, struct uio *uio, struct ucred *active_cred,
int flags, struct thread *td)
{
Implement read(2)/write(2) and neccessary lseek(2) for posix shmfd. Add MAC framework entries for posix shm read and write. Do not allow implicit extension of the underlying memory segment past the limit set by ftruncate(2) by either of the syscalls. Read and write returns short i/o, lseek(2) fails with EINVAL when resulting offset does not fit into the limit. Discussed with: alc Tested by: pho Sponsored by: The FreeBSD Foundation
2013-08-21 17:45:00 +00:00
struct shmfd *shmfd;
void *rl_cookie;
int error;
Add a new file descriptor type for IPC shared memory objects and use it to implement shm_open(2) and shm_unlink(2) in the kernel: - Each shared memory file descriptor is associated with a swap-backed vm object which provides the backing store. Each descriptor starts off with a size of zero, but the size can be altered via ftruncate(2). The shared memory file descriptors also support fstat(2). read(2), write(2), ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared memory file descriptors. - shm_open(2) and shm_unlink(2) are now implemented as system calls that manage shared memory file descriptors. The virtual namespace that maps pathnames to shared memory file descriptors is implemented as a hash table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash of the pathname. - As an extension, the constant 'SHM_ANON' may be specified in place of the path argument to shm_open(2). In this case, an unnamed shared memory file descriptor will be created similar to the IPC_PRIVATE key for shmget(2). Note that the shared memory object can still be shared among processes by sharing the file descriptor via fork(2) or sendmsg(2), but it is unnamed. This effectively serves to implement the getmemfd() idea bandied about the lists several times over the years. - The backing store for shared memory file descriptors are garbage collected when they are not referenced by any open file descriptors or the shm_open(2) virtual namespace. Submitted by: dillon, peter (previous versions) Submitted by: rwatson (I based this on his version) Reviewed by: alc (suggested converting getmemfd() to shm_open())
2008-01-08 21:58:16 +00:00
Implement read(2)/write(2) and neccessary lseek(2) for posix shmfd. Add MAC framework entries for posix shm read and write. Do not allow implicit extension of the underlying memory segment past the limit set by ftruncate(2) by either of the syscalls. Read and write returns short i/o, lseek(2) fails with EINVAL when resulting offset does not fit into the limit. Discussed with: alc Tested by: pho Sponsored by: The FreeBSD Foundation
2013-08-21 17:45:00 +00:00
shmfd = fp->f_data;
foffset_lock_uio(fp, uio, flags);
rl_cookie = rangelock_rlock(&shmfd->shm_rl, uio->uio_offset,
uio->uio_offset + uio->uio_resid, &shmfd->shm_mtx);
#ifdef MAC
error = mac_posixshm_check_read(active_cred, fp->f_cred, shmfd);
if (error)
return (error);
#endif
error = uiomove_object(shmfd->shm_object, shmfd->shm_size, uio);
rangelock_unlock(&shmfd->shm_rl, rl_cookie, &shmfd->shm_mtx);
foffset_unlock_uio(fp, uio, flags);
return (error);
Add a new file descriptor type for IPC shared memory objects and use it to implement shm_open(2) and shm_unlink(2) in the kernel: - Each shared memory file descriptor is associated with a swap-backed vm object which provides the backing store. Each descriptor starts off with a size of zero, but the size can be altered via ftruncate(2). The shared memory file descriptors also support fstat(2). read(2), write(2), ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared memory file descriptors. - shm_open(2) and shm_unlink(2) are now implemented as system calls that manage shared memory file descriptors. The virtual namespace that maps pathnames to shared memory file descriptors is implemented as a hash table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash of the pathname. - As an extension, the constant 'SHM_ANON' may be specified in place of the path argument to shm_open(2). In this case, an unnamed shared memory file descriptor will be created similar to the IPC_PRIVATE key for shmget(2). Note that the shared memory object can still be shared among processes by sharing the file descriptor via fork(2) or sendmsg(2), but it is unnamed. This effectively serves to implement the getmemfd() idea bandied about the lists several times over the years. - The backing store for shared memory file descriptors are garbage collected when they are not referenced by any open file descriptors or the shm_open(2) virtual namespace. Submitted by: dillon, peter (previous versions) Submitted by: rwatson (I based this on his version) Reviewed by: alc (suggested converting getmemfd() to shm_open())
2008-01-08 21:58:16 +00:00
}
static int
shm_write(struct file *fp, struct uio *uio, struct ucred *active_cred,
int flags, struct thread *td)
{
Implement read(2)/write(2) and neccessary lseek(2) for posix shmfd. Add MAC framework entries for posix shm read and write. Do not allow implicit extension of the underlying memory segment past the limit set by ftruncate(2) by either of the syscalls. Read and write returns short i/o, lseek(2) fails with EINVAL when resulting offset does not fit into the limit. Discussed with: alc Tested by: pho Sponsored by: The FreeBSD Foundation
2013-08-21 17:45:00 +00:00
struct shmfd *shmfd;
void *rl_cookie;
int error;
Add a new file descriptor type for IPC shared memory objects and use it to implement shm_open(2) and shm_unlink(2) in the kernel: - Each shared memory file descriptor is associated with a swap-backed vm object which provides the backing store. Each descriptor starts off with a size of zero, but the size can be altered via ftruncate(2). The shared memory file descriptors also support fstat(2). read(2), write(2), ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared memory file descriptors. - shm_open(2) and shm_unlink(2) are now implemented as system calls that manage shared memory file descriptors. The virtual namespace that maps pathnames to shared memory file descriptors is implemented as a hash table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash of the pathname. - As an extension, the constant 'SHM_ANON' may be specified in place of the path argument to shm_open(2). In this case, an unnamed shared memory file descriptor will be created similar to the IPC_PRIVATE key for shmget(2). Note that the shared memory object can still be shared among processes by sharing the file descriptor via fork(2) or sendmsg(2), but it is unnamed. This effectively serves to implement the getmemfd() idea bandied about the lists several times over the years. - The backing store for shared memory file descriptors are garbage collected when they are not referenced by any open file descriptors or the shm_open(2) virtual namespace. Submitted by: dillon, peter (previous versions) Submitted by: rwatson (I based this on his version) Reviewed by: alc (suggested converting getmemfd() to shm_open())
2008-01-08 21:58:16 +00:00
Implement read(2)/write(2) and neccessary lseek(2) for posix shmfd. Add MAC framework entries for posix shm read and write. Do not allow implicit extension of the underlying memory segment past the limit set by ftruncate(2) by either of the syscalls. Read and write returns short i/o, lseek(2) fails with EINVAL when resulting offset does not fit into the limit. Discussed with: alc Tested by: pho Sponsored by: The FreeBSD Foundation
2013-08-21 17:45:00 +00:00
shmfd = fp->f_data;
#ifdef MAC
error = mac_posixshm_check_write(active_cred, fp->f_cred, shmfd);
if (error)
return (error);
#endif
foffset_lock_uio(fp, uio, flags);
if ((flags & FOF_OFFSET) == 0) {
rl_cookie = rangelock_wlock(&shmfd->shm_rl, 0, OFF_MAX,
&shmfd->shm_mtx);
} else {
rl_cookie = rangelock_wlock(&shmfd->shm_rl, uio->uio_offset,
uio->uio_offset + uio->uio_resid, &shmfd->shm_mtx);
}
error = uiomove_object(shmfd->shm_object, shmfd->shm_size, uio);
rangelock_unlock(&shmfd->shm_rl, rl_cookie, &shmfd->shm_mtx);
foffset_unlock_uio(fp, uio, flags);
return (error);
Add a new file descriptor type for IPC shared memory objects and use it to implement shm_open(2) and shm_unlink(2) in the kernel: - Each shared memory file descriptor is associated with a swap-backed vm object which provides the backing store. Each descriptor starts off with a size of zero, but the size can be altered via ftruncate(2). The shared memory file descriptors also support fstat(2). read(2), write(2), ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared memory file descriptors. - shm_open(2) and shm_unlink(2) are now implemented as system calls that manage shared memory file descriptors. The virtual namespace that maps pathnames to shared memory file descriptors is implemented as a hash table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash of the pathname. - As an extension, the constant 'SHM_ANON' may be specified in place of the path argument to shm_open(2). In this case, an unnamed shared memory file descriptor will be created similar to the IPC_PRIVATE key for shmget(2). Note that the shared memory object can still be shared among processes by sharing the file descriptor via fork(2) or sendmsg(2), but it is unnamed. This effectively serves to implement the getmemfd() idea bandied about the lists several times over the years. - The backing store for shared memory file descriptors are garbage collected when they are not referenced by any open file descriptors or the shm_open(2) virtual namespace. Submitted by: dillon, peter (previous versions) Submitted by: rwatson (I based this on his version) Reviewed by: alc (suggested converting getmemfd() to shm_open())
2008-01-08 21:58:16 +00:00
}
static int
shm_truncate(struct file *fp, off_t length, struct ucred *active_cred,
struct thread *td)
{
struct shmfd *shmfd;
#ifdef MAC
int error;
#endif
shmfd = fp->f_data;
#ifdef MAC
error = mac_posixshm_check_truncate(active_cred, fp->f_cred, shmfd);
if (error)
return (error);
#endif
Implement global and per-uid accounting of the anonymous memory. Add rlimit RLIMIT_SWAP that limits the amount of swap that may be reserved for the uid. The accounting information (charge) is associated with either map entry, or vm object backing the entry, assuming the object is the first one in the shadow chain and entry does not require COW. Charge is moved from entry to object on allocation of the object, e.g. during the mmap, assuming the object is allocated, or on the first page fault on the entry. It moves back to the entry on forks due to COW setup. The per-entry granularity of accounting makes the charge process fair for processes that change uid during lifetime, and decrements charge for proper uid when region is unmapped. The interface of vm_pager_allocate(9) is extended by adding struct ucred *, that is used to charge appropriate uid when allocation if performed by kernel, e.g. md(4). Several syscalls, among them is fork(2), may now return ENOMEM when global or per-uid limits are enforced. In collaboration with: pho Reviewed by: alc Approved by: re (kensmith)
2009-06-23 20:45:22 +00:00
return (shm_dotruncate(shmfd, length));
Add a new file descriptor type for IPC shared memory objects and use it to implement shm_open(2) and shm_unlink(2) in the kernel: - Each shared memory file descriptor is associated with a swap-backed vm object which provides the backing store. Each descriptor starts off with a size of zero, but the size can be altered via ftruncate(2). The shared memory file descriptors also support fstat(2). read(2), write(2), ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared memory file descriptors. - shm_open(2) and shm_unlink(2) are now implemented as system calls that manage shared memory file descriptors. The virtual namespace that maps pathnames to shared memory file descriptors is implemented as a hash table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash of the pathname. - As an extension, the constant 'SHM_ANON' may be specified in place of the path argument to shm_open(2). In this case, an unnamed shared memory file descriptor will be created similar to the IPC_PRIVATE key for shmget(2). Note that the shared memory object can still be shared among processes by sharing the file descriptor via fork(2) or sendmsg(2), but it is unnamed. This effectively serves to implement the getmemfd() idea bandied about the lists several times over the years. - The backing store for shared memory file descriptors are garbage collected when they are not referenced by any open file descriptors or the shm_open(2) virtual namespace. Submitted by: dillon, peter (previous versions) Submitted by: rwatson (I based this on his version) Reviewed by: alc (suggested converting getmemfd() to shm_open())
2008-01-08 21:58:16 +00:00
}
static int
shm_stat(struct file *fp, struct stat *sb, struct ucred *active_cred,
struct thread *td)
{
struct shmfd *shmfd;
#ifdef MAC
int error;
#endif
shmfd = fp->f_data;
#ifdef MAC
error = mac_posixshm_check_stat(active_cred, fp->f_cred, shmfd);
if (error)
return (error);
#endif
/*
* Attempt to return sanish values for fstat() on a memory file
* descriptor.
*/
bzero(sb, sizeof(*sb));
sb->st_blksize = PAGE_SIZE;
sb->st_size = shmfd->shm_size;
sb->st_blocks = (sb->st_size + sb->st_blksize - 1) / sb->st_blksize;
Add the fo_chown and fo_chmod methods to struct fileops and use them to implement fchown(2) and fchmod(2) support for several file types that previously lacked it. Add MAC entries for chown/chmod done on posix shared memory and (old) in-kernel posix semaphores. Based on the submission by: glebius Reviewed by: rwatson Approved by: re (bz)
2011-08-16 20:07:47 +00:00
mtx_lock(&shm_timestamp_lock);
Rename st_*timespec fields to st_*tim for POSIX 2008 compliance. A nice thing about POSIX 2008 is that it finally standardizes a way to obtain file access/modification/change times in sub-second precision, namely using struct timespec, which we already have for a very long time. Unfortunately POSIX uses different names. This commit adds compatibility macros, so existing code should still build properly. Also change all source code in the kernel to work without any of the compatibility macros. This makes it all a less ambiguous. I am also renaming st_birthtime to st_birthtim, even though it was a local extension anyway. It seems Cygwin also has a st_birthtim.
2010-03-28 13:13:22 +00:00
sb->st_atim = shmfd->shm_atime;
sb->st_ctim = shmfd->shm_ctime;
sb->st_mtim = shmfd->shm_mtime;
Add the fo_chown and fo_chmod methods to struct fileops and use them to implement fchown(2) and fchmod(2) support for several file types that previously lacked it. Add MAC entries for chown/chmod done on posix shared memory and (old) in-kernel posix semaphores. Based on the submission by: glebius Reviewed by: rwatson Approved by: re (bz)
2011-08-16 20:07:47 +00:00
sb->st_birthtim = shmfd->shm_birthtime;
sb->st_mode = S_IFREG | shmfd->shm_mode; /* XXX */
Add a new file descriptor type for IPC shared memory objects and use it to implement shm_open(2) and shm_unlink(2) in the kernel: - Each shared memory file descriptor is associated with a swap-backed vm object which provides the backing store. Each descriptor starts off with a size of zero, but the size can be altered via ftruncate(2). The shared memory file descriptors also support fstat(2). read(2), write(2), ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared memory file descriptors. - shm_open(2) and shm_unlink(2) are now implemented as system calls that manage shared memory file descriptors. The virtual namespace that maps pathnames to shared memory file descriptors is implemented as a hash table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash of the pathname. - As an extension, the constant 'SHM_ANON' may be specified in place of the path argument to shm_open(2). In this case, an unnamed shared memory file descriptor will be created similar to the IPC_PRIVATE key for shmget(2). Note that the shared memory object can still be shared among processes by sharing the file descriptor via fork(2) or sendmsg(2), but it is unnamed. This effectively serves to implement the getmemfd() idea bandied about the lists several times over the years. - The backing store for shared memory file descriptors are garbage collected when they are not referenced by any open file descriptors or the shm_open(2) virtual namespace. Submitted by: dillon, peter (previous versions) Submitted by: rwatson (I based this on his version) Reviewed by: alc (suggested converting getmemfd() to shm_open())
2008-01-08 21:58:16 +00:00
sb->st_uid = shmfd->shm_uid;
sb->st_gid = shmfd->shm_gid;
Add the fo_chown and fo_chmod methods to struct fileops and use them to implement fchown(2) and fchmod(2) support for several file types that previously lacked it. Add MAC entries for chown/chmod done on posix shared memory and (old) in-kernel posix semaphores. Based on the submission by: glebius Reviewed by: rwatson Approved by: re (bz)
2011-08-16 20:07:47 +00:00
mtx_unlock(&shm_timestamp_lock);
Use a unit number allocator to provide suitable st_dev and st_ino values for POSIX shared memory descriptors. The implementation is similar to that used for pipes. MFC after: 1 week
2014-08-29 18:18:29 +00:00
sb->st_dev = shm_dev_ino;
sb->st_ino = shmfd->shm_ino;
Add a new file descriptor type for IPC shared memory objects and use it to implement shm_open(2) and shm_unlink(2) in the kernel: - Each shared memory file descriptor is associated with a swap-backed vm object which provides the backing store. Each descriptor starts off with a size of zero, but the size can be altered via ftruncate(2). The shared memory file descriptors also support fstat(2). read(2), write(2), ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared memory file descriptors. - shm_open(2) and shm_unlink(2) are now implemented as system calls that manage shared memory file descriptors. The virtual namespace that maps pathnames to shared memory file descriptors is implemented as a hash table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash of the pathname. - As an extension, the constant 'SHM_ANON' may be specified in place of the path argument to shm_open(2). In this case, an unnamed shared memory file descriptor will be created similar to the IPC_PRIVATE key for shmget(2). Note that the shared memory object can still be shared among processes by sharing the file descriptor via fork(2) or sendmsg(2), but it is unnamed. This effectively serves to implement the getmemfd() idea bandied about the lists several times over the years. - The backing store for shared memory file descriptors are garbage collected when they are not referenced by any open file descriptors or the shm_open(2) virtual namespace. Submitted by: dillon, peter (previous versions) Submitted by: rwatson (I based this on his version) Reviewed by: alc (suggested converting getmemfd() to shm_open())
2008-01-08 21:58:16 +00:00
return (0);
}
static int
shm_close(struct file *fp, struct thread *td)
{
struct shmfd *shmfd;
shmfd = fp->f_data;
fp->f_data = NULL;
shm_drop(shmfd);
return (0);
}
Implement global and per-uid accounting of the anonymous memory. Add rlimit RLIMIT_SWAP that limits the amount of swap that may be reserved for the uid. The accounting information (charge) is associated with either map entry, or vm object backing the entry, assuming the object is the first one in the shadow chain and entry does not require COW. Charge is moved from entry to object on allocation of the object, e.g. during the mmap, assuming the object is allocated, or on the first page fault on the entry. It moves back to the entry on forks due to COW setup. The per-entry granularity of accounting makes the charge process fair for processes that change uid during lifetime, and decrements charge for proper uid when region is unmapped. The interface of vm_pager_allocate(9) is extended by adding struct ucred *, that is used to charge appropriate uid when allocation if performed by kernel, e.g. md(4). Several syscalls, among them is fork(2), may now return ENOMEM when global or per-uid limits are enforced. In collaboration with: pho Reviewed by: alc Approved by: re (kensmith)
2009-06-23 20:45:22 +00:00
static int
Add a new file descriptor type for IPC shared memory objects and use it to implement shm_open(2) and shm_unlink(2) in the kernel: - Each shared memory file descriptor is associated with a swap-backed vm object which provides the backing store. Each descriptor starts off with a size of zero, but the size can be altered via ftruncate(2). The shared memory file descriptors also support fstat(2). read(2), write(2), ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared memory file descriptors. - shm_open(2) and shm_unlink(2) are now implemented as system calls that manage shared memory file descriptors. The virtual namespace that maps pathnames to shared memory file descriptors is implemented as a hash table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash of the pathname. - As an extension, the constant 'SHM_ANON' may be specified in place of the path argument to shm_open(2). In this case, an unnamed shared memory file descriptor will be created similar to the IPC_PRIVATE key for shmget(2). Note that the shared memory object can still be shared among processes by sharing the file descriptor via fork(2) or sendmsg(2), but it is unnamed. This effectively serves to implement the getmemfd() idea bandied about the lists several times over the years. - The backing store for shared memory file descriptors are garbage collected when they are not referenced by any open file descriptors or the shm_open(2) virtual namespace. Submitted by: dillon, peter (previous versions) Submitted by: rwatson (I based this on his version) Reviewed by: alc (suggested converting getmemfd() to shm_open())
2008-01-08 21:58:16 +00:00
shm_dotruncate(struct shmfd *shmfd, off_t length)
{
vm_object_t object;
Make KPI of vm_pager_get_pages() more strict: if a pager changes a page in the requested array, then it is responsible for disposition of previous page and is responsible for updating the entry in the requested array. Now consumers of KPI do not need to re-lookup the pages after call to vm_pager_get_pages(). Reviewed by: kib Sponsored by: Netflix Sponsored by: Nginx, Inc.
2015-06-12 11:32:20 +00:00
vm_page_t m;
Correct an error of omission in the implementation of the truncation operation on POSIX shared memory objects and tmpfs. Previously, neither of these modules correctly handled the case in which the new size of the object or file was not a multiple of the page size. Specifically, they did not handle partial page truncation of data stored on swap. As a result, stale data might later be returned to an application. Interestingly, a data inconsistency was less likely to occur under tmpfs than POSIX shared memory objects. The reason being that a different mistake by the tmpfs truncation operation helped avoid a data inconsistency. If the data was still resident in memory in a PG_CACHED page, then the tmpfs truncation operation would reactivate that page, zero the truncated portion, and leave the page pinned in memory. More precisely, the benevolent error was that the truncation operation didn't add the reactivated page to any of the paging queues, effectively pinning the page. This page would remain pinned until the file was destroyed or the page was read or written. With this change, the page is now added to the inactive queue. Discussed with: jhb Reviewed by: kib (an earlier version) MFC after: 3 weeks
2012-01-08 20:09:26 +00:00
vm_pindex_t idx, nobjsize;
Implement global and per-uid accounting of the anonymous memory. Add rlimit RLIMIT_SWAP that limits the amount of swap that may be reserved for the uid. The accounting information (charge) is associated with either map entry, or vm object backing the entry, assuming the object is the first one in the shadow chain and entry does not require COW. Charge is moved from entry to object on allocation of the object, e.g. during the mmap, assuming the object is allocated, or on the first page fault on the entry. It moves back to the entry on forks due to COW setup. The per-entry granularity of accounting makes the charge process fair for processes that change uid during lifetime, and decrements charge for proper uid when region is unmapped. The interface of vm_pager_allocate(9) is extended by adding struct ucred *, that is used to charge appropriate uid when allocation if performed by kernel, e.g. md(4). Several syscalls, among them is fork(2), may now return ENOMEM when global or per-uid limits are enforced. In collaboration with: pho Reviewed by: alc Approved by: re (kensmith)
2009-06-23 20:45:22 +00:00
vm_ooffset_t delta;
Correct an error of omission in the implementation of the truncation operation on POSIX shared memory objects and tmpfs. Previously, neither of these modules correctly handled the case in which the new size of the object or file was not a multiple of the page size. Specifically, they did not handle partial page truncation of data stored on swap. As a result, stale data might later be returned to an application. Interestingly, a data inconsistency was less likely to occur under tmpfs than POSIX shared memory objects. The reason being that a different mistake by the tmpfs truncation operation helped avoid a data inconsistency. If the data was still resident in memory in a PG_CACHED page, then the tmpfs truncation operation would reactivate that page, zero the truncated portion, and leave the page pinned in memory. More precisely, the benevolent error was that the truncation operation didn't add the reactivated page to any of the paging queues, effectively pinning the page. This page would remain pinned until the file was destroyed or the page was read or written. With this change, the page is now added to the inactive queue. Discussed with: jhb Reviewed by: kib (an earlier version) MFC after: 3 weeks
2012-01-08 20:09:26 +00:00
int base, rv;
Add a new file descriptor type for IPC shared memory objects and use it to implement shm_open(2) and shm_unlink(2) in the kernel: - Each shared memory file descriptor is associated with a swap-backed vm object which provides the backing store. Each descriptor starts off with a size of zero, but the size can be altered via ftruncate(2). The shared memory file descriptors also support fstat(2). read(2), write(2), ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared memory file descriptors. - shm_open(2) and shm_unlink(2) are now implemented as system calls that manage shared memory file descriptors. The virtual namespace that maps pathnames to shared memory file descriptors is implemented as a hash table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash of the pathname. - As an extension, the constant 'SHM_ANON' may be specified in place of the path argument to shm_open(2). In this case, an unnamed shared memory file descriptor will be created similar to the IPC_PRIVATE key for shmget(2). Note that the shared memory object can still be shared among processes by sharing the file descriptor via fork(2) or sendmsg(2), but it is unnamed. This effectively serves to implement the getmemfd() idea bandied about the lists several times over the years. - The backing store for shared memory file descriptors are garbage collected when they are not referenced by any open file descriptors or the shm_open(2) virtual namespace. Submitted by: dillon, peter (previous versions) Submitted by: rwatson (I based this on his version) Reviewed by: alc (suggested converting getmemfd() to shm_open())
2008-01-08 21:58:16 +00:00
object = shmfd->shm_object;
Rename VM_OBJECT_LOCK(), VM_OBJECT_UNLOCK() and VM_OBJECT_TRYLOCK() to their "write" versions. Sponsored by: EMC / Isilon storage division
2013-02-20 12:03:20 +00:00
VM_OBJECT_WLOCK(object);
Add a new file descriptor type for IPC shared memory objects and use it to implement shm_open(2) and shm_unlink(2) in the kernel: - Each shared memory file descriptor is associated with a swap-backed vm object which provides the backing store. Each descriptor starts off with a size of zero, but the size can be altered via ftruncate(2). The shared memory file descriptors also support fstat(2). read(2), write(2), ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared memory file descriptors. - shm_open(2) and shm_unlink(2) are now implemented as system calls that manage shared memory file descriptors. The virtual namespace that maps pathnames to shared memory file descriptors is implemented as a hash table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash of the pathname. - As an extension, the constant 'SHM_ANON' may be specified in place of the path argument to shm_open(2). In this case, an unnamed shared memory file descriptor will be created similar to the IPC_PRIVATE key for shmget(2). Note that the shared memory object can still be shared among processes by sharing the file descriptor via fork(2) or sendmsg(2), but it is unnamed. This effectively serves to implement the getmemfd() idea bandied about the lists several times over the years. - The backing store for shared memory file descriptors are garbage collected when they are not referenced by any open file descriptors or the shm_open(2) virtual namespace. Submitted by: dillon, peter (previous versions) Submitted by: rwatson (I based this on his version) Reviewed by: alc (suggested converting getmemfd() to shm_open())
2008-01-08 21:58:16 +00:00
if (length == shmfd->shm_size) {
Rename VM_OBJECT_LOCK(), VM_OBJECT_UNLOCK() and VM_OBJECT_TRYLOCK() to their "write" versions. Sponsored by: EMC / Isilon storage division
2013-02-20 12:03:20 +00:00
VM_OBJECT_WUNLOCK(object);
Implement global and per-uid accounting of the anonymous memory. Add rlimit RLIMIT_SWAP that limits the amount of swap that may be reserved for the uid. The accounting information (charge) is associated with either map entry, or vm object backing the entry, assuming the object is the first one in the shadow chain and entry does not require COW. Charge is moved from entry to object on allocation of the object, e.g. during the mmap, assuming the object is allocated, or on the first page fault on the entry. It moves back to the entry on forks due to COW setup. The per-entry granularity of accounting makes the charge process fair for processes that change uid during lifetime, and decrements charge for proper uid when region is unmapped. The interface of vm_pager_allocate(9) is extended by adding struct ucred *, that is used to charge appropriate uid when allocation if performed by kernel, e.g. md(4). Several syscalls, among them is fork(2), may now return ENOMEM when global or per-uid limits are enforced. In collaboration with: pho Reviewed by: alc Approved by: re (kensmith)
2009-06-23 20:45:22 +00:00
return (0);
Add a new file descriptor type for IPC shared memory objects and use it to implement shm_open(2) and shm_unlink(2) in the kernel: - Each shared memory file descriptor is associated with a swap-backed vm object which provides the backing store. Each descriptor starts off with a size of zero, but the size can be altered via ftruncate(2). The shared memory file descriptors also support fstat(2). read(2), write(2), ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared memory file descriptors. - shm_open(2) and shm_unlink(2) are now implemented as system calls that manage shared memory file descriptors. The virtual namespace that maps pathnames to shared memory file descriptors is implemented as a hash table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash of the pathname. - As an extension, the constant 'SHM_ANON' may be specified in place of the path argument to shm_open(2). In this case, an unnamed shared memory file descriptor will be created similar to the IPC_PRIVATE key for shmget(2). Note that the shared memory object can still be shared among processes by sharing the file descriptor via fork(2) or sendmsg(2), but it is unnamed. This effectively serves to implement the getmemfd() idea bandied about the lists several times over the years. - The backing store for shared memory file descriptors are garbage collected when they are not referenced by any open file descriptors or the shm_open(2) virtual namespace. Submitted by: dillon, peter (previous versions) Submitted by: rwatson (I based this on his version) Reviewed by: alc (suggested converting getmemfd() to shm_open())
2008-01-08 21:58:16 +00:00
}
nobjsize = OFF_TO_IDX(length + PAGE_MASK);
/* Are we shrinking? If so, trim the end. */
if (length < shmfd->shm_size) {
Add a helper API to allow in-kernel code to map portions of shared memory objects created by shm_open(2) into the kernel's address space. This provides a convenient way for creating shared memory buffers between userland and the kernel without requiring custom character devices.
2011-12-14 22:22:19 +00:00
/*
* Disallow any requests to shrink the size if this
* object is mapped into the kernel.
*/
if (shmfd->shm_kmappings > 0) {
Rename VM_OBJECT_LOCK(), VM_OBJECT_UNLOCK() and VM_OBJECT_TRYLOCK() to their "write" versions. Sponsored by: EMC / Isilon storage division
2013-02-20 12:03:20 +00:00
VM_OBJECT_WUNLOCK(object);
Add a helper API to allow in-kernel code to map portions of shared memory objects created by shm_open(2) into the kernel's address space. This provides a convenient way for creating shared memory buffers between userland and the kernel without requiring custom character devices.
2011-12-14 22:22:19 +00:00
return (EBUSY);
}
Correct an error of omission in the implementation of the truncation operation on POSIX shared memory objects and tmpfs. Previously, neither of these modules correctly handled the case in which the new size of the object or file was not a multiple of the page size. Specifically, they did not handle partial page truncation of data stored on swap. As a result, stale data might later be returned to an application. Interestingly, a data inconsistency was less likely to occur under tmpfs than POSIX shared memory objects. The reason being that a different mistake by the tmpfs truncation operation helped avoid a data inconsistency. If the data was still resident in memory in a PG_CACHED page, then the tmpfs truncation operation would reactivate that page, zero the truncated portion, and leave the page pinned in memory. More precisely, the benevolent error was that the truncation operation didn't add the reactivated page to any of the paging queues, effectively pinning the page. This page would remain pinned until the file was destroyed or the page was read or written. With this change, the page is now added to the inactive queue. Discussed with: jhb Reviewed by: kib (an earlier version) MFC after: 3 weeks
2012-01-08 20:09:26 +00:00
/*
* Zero the truncated part of the last page.
*/
base = length & PAGE_MASK;
if (base != 0) {
idx = OFF_TO_IDX(length);
retry:
m = vm_page_lookup(object, idx);
if (m != NULL) {
The soft and hard busy mechanism rely on the vm object lock to work. Unify the 2 concept into a real, minimal, sxlock where the shared acquisition represent the soft busy and the exclusive acquisition represent the hard busy. The old VPO_WANTED mechanism becames the hard-path for this new lock and it becomes per-page rather than per-object. The vm_object lock becames an interlock for this functionality: it can be held in both read or write mode. However, if the vm_object lock is held in read mode while acquiring or releasing the busy state, the thread owner cannot make any assumption on the busy state unless it is also busying it. Also: - Add a new flag to directly shared busy pages while vm_page_alloc and vm_page_grab are being executed. This will be very helpful once these functions happen under a read object lock. - Move the swapping sleep into its own per-object flag The KPI is heavilly changed this is why the version is bumped. It is very likely that some VM ports users will need to change their own code. Sponsored by: EMC / Isilon storage division Discussed with: alc Reviewed by: jeff, kib Tested by: gavin, bapt (older version) Tested by: pho, scottl
2013-08-09 11:11:11 +00:00
if (vm_page_sleep_if_busy(m, "shmtrc"))
Correct an error of omission in the implementation of the truncation operation on POSIX shared memory objects and tmpfs. Previously, neither of these modules correctly handled the case in which the new size of the object or file was not a multiple of the page size. Specifically, they did not handle partial page truncation of data stored on swap. As a result, stale data might later be returned to an application. Interestingly, a data inconsistency was less likely to occur under tmpfs than POSIX shared memory objects. The reason being that a different mistake by the tmpfs truncation operation helped avoid a data inconsistency. If the data was still resident in memory in a PG_CACHED page, then the tmpfs truncation operation would reactivate that page, zero the truncated portion, and leave the page pinned in memory. More precisely, the benevolent error was that the truncation operation didn't add the reactivated page to any of the paging queues, effectively pinning the page. This page would remain pinned until the file was destroyed or the page was read or written. With this change, the page is now added to the inactive queue. Discussed with: jhb Reviewed by: kib (an earlier version) MFC after: 3 weeks
2012-01-08 20:09:26 +00:00
goto retry;
} else if (vm_pager_has_page(object, idx, NULL, NULL)) {
m = vm_page_alloc(object, idx, VM_ALLOC_NORMAL);
if (m == NULL) {
Rename VM_OBJECT_LOCK(), VM_OBJECT_UNLOCK() and VM_OBJECT_TRYLOCK() to their "write" versions. Sponsored by: EMC / Isilon storage division
2013-02-20 12:03:20 +00:00
VM_OBJECT_WUNLOCK(object);
Correct an error of omission in the implementation of the truncation operation on POSIX shared memory objects and tmpfs. Previously, neither of these modules correctly handled the case in which the new size of the object or file was not a multiple of the page size. Specifically, they did not handle partial page truncation of data stored on swap. As a result, stale data might later be returned to an application. Interestingly, a data inconsistency was less likely to occur under tmpfs than POSIX shared memory objects. The reason being that a different mistake by the tmpfs truncation operation helped avoid a data inconsistency. If the data was still resident in memory in a PG_CACHED page, then the tmpfs truncation operation would reactivate that page, zero the truncated portion, and leave the page pinned in memory. More precisely, the benevolent error was that the truncation operation didn't add the reactivated page to any of the paging queues, effectively pinning the page. This page would remain pinned until the file was destroyed or the page was read or written. With this change, the page is now added to the inactive queue. Discussed with: jhb Reviewed by: kib (an earlier version) MFC after: 3 weeks
2012-01-08 20:09:26 +00:00
VM_WAIT;
Rename VM_OBJECT_LOCK(), VM_OBJECT_UNLOCK() and VM_OBJECT_TRYLOCK() to their "write" versions. Sponsored by: EMC / Isilon storage division
2013-02-20 12:03:20 +00:00
VM_OBJECT_WLOCK(object);
Correct an error of omission in the implementation of the truncation operation on POSIX shared memory objects and tmpfs. Previously, neither of these modules correctly handled the case in which the new size of the object or file was not a multiple of the page size. Specifically, they did not handle partial page truncation of data stored on swap. As a result, stale data might later be returned to an application. Interestingly, a data inconsistency was less likely to occur under tmpfs than POSIX shared memory objects. The reason being that a different mistake by the tmpfs truncation operation helped avoid a data inconsistency. If the data was still resident in memory in a PG_CACHED page, then the tmpfs truncation operation would reactivate that page, zero the truncated portion, and leave the page pinned in memory. More precisely, the benevolent error was that the truncation operation didn't add the reactivated page to any of the paging queues, effectively pinning the page. This page would remain pinned until the file was destroyed or the page was read or written. With this change, the page is now added to the inactive queue. Discussed with: jhb Reviewed by: kib (an earlier version) MFC after: 3 weeks
2012-01-08 20:09:26 +00:00
goto retry;
Make KPI of vm_pager_get_pages() more strict: if a pager changes a page in the requested array, then it is responsible for disposition of previous page and is responsible for updating the entry in the requested array. Now consumers of KPI do not need to re-lookup the pages after call to vm_pager_get_pages(). Reviewed by: kib Sponsored by: Netflix Sponsored by: Nginx, Inc.
2015-06-12 11:32:20 +00:00
} else if (m->valid != VM_PAGE_BITS_ALL)
rv = vm_pager_get_pages(object, &m, 1,
A change to KPI of vm_pager_get_pages() and underlying VOP_GETPAGES(). o With new KPI consumers can request contiguous ranges of pages, and unlike before, all pages will be kept busied on return, like it was done before with the 'reqpage' only. Now the reqpage goes away. With new interface it is easier to implement code protected from race conditions. Such arrayed requests for now should be preceeded by a call to vm_pager_haspage() to make sure that request is possible. This could be improved later, making vm_pager_haspage() obsolete. Strenghtening the promises on the business of the array of pages allows us to remove such hacks as swp_pager_free_nrpage() and vm_pager_free_nonreq(). o New KPI accepts two integer pointers that may optionally point at values for read ahead and read behind, that a pager may do, if it can. These pages are completely owned by pager, and not controlled by the caller. This shifts the UFS-specific readahead logic from vm_fault.c, which should be file system agnostic, into vnode_pager.c. It also removes one VOP_BMAP() request per hard fault. Discussed with: kib, alc, jeff, scottl Sponsored by: Nginx, Inc. Sponsored by: Netflix
2015-12-16 21:30:45 +00:00
NULL, NULL);
Make KPI of vm_pager_get_pages() more strict: if a pager changes a page in the requested array, then it is responsible for disposition of previous page and is responsible for updating the entry in the requested array. Now consumers of KPI do not need to re-lookup the pages after call to vm_pager_get_pages(). Reviewed by: kib Sponsored by: Netflix Sponsored by: Nginx, Inc.
2015-06-12 11:32:20 +00:00
else
Correct an error of omission in the implementation of the truncation operation on POSIX shared memory objects and tmpfs. Previously, neither of these modules correctly handled the case in which the new size of the object or file was not a multiple of the page size. Specifically, they did not handle partial page truncation of data stored on swap. As a result, stale data might later be returned to an application. Interestingly, a data inconsistency was less likely to occur under tmpfs than POSIX shared memory objects. The reason being that a different mistake by the tmpfs truncation operation helped avoid a data inconsistency. If the data was still resident in memory in a PG_CACHED page, then the tmpfs truncation operation would reactivate that page, zero the truncated portion, and leave the page pinned in memory. More precisely, the benevolent error was that the truncation operation didn't add the reactivated page to any of the paging queues, effectively pinning the page. This page would remain pinned until the file was destroyed or the page was read or written. With this change, the page is now added to the inactive queue. Discussed with: jhb Reviewed by: kib (an earlier version) MFC after: 3 weeks
2012-01-08 20:09:26 +00:00
/* A cached page was reactivated. */
rv = VM_PAGER_OK;
vm_page_lock(m);
if (rv == VM_PAGER_OK) {
vm_page_deactivate(m);
vm_page_unlock(m);
The soft and hard busy mechanism rely on the vm object lock to work. Unify the 2 concept into a real, minimal, sxlock where the shared acquisition represent the soft busy and the exclusive acquisition represent the hard busy. The old VPO_WANTED mechanism becames the hard-path for this new lock and it becomes per-page rather than per-object. The vm_object lock becames an interlock for this functionality: it can be held in both read or write mode. However, if the vm_object lock is held in read mode while acquiring or releasing the busy state, the thread owner cannot make any assumption on the busy state unless it is also busying it. Also: - Add a new flag to directly shared busy pages while vm_page_alloc and vm_page_grab are being executed. This will be very helpful once these functions happen under a read object lock. - Move the swapping sleep into its own per-object flag The KPI is heavilly changed this is why the version is bumped. It is very likely that some VM ports users will need to change their own code. Sponsored by: EMC / Isilon storage division Discussed with: alc Reviewed by: jeff, kib Tested by: gavin, bapt (older version) Tested by: pho, scottl
2013-08-09 11:11:11 +00:00
vm_page_xunbusy(m);
Correct an error of omission in the implementation of the truncation operation on POSIX shared memory objects and tmpfs. Previously, neither of these modules correctly handled the case in which the new size of the object or file was not a multiple of the page size. Specifically, they did not handle partial page truncation of data stored on swap. As a result, stale data might later be returned to an application. Interestingly, a data inconsistency was less likely to occur under tmpfs than POSIX shared memory objects. The reason being that a different mistake by the tmpfs truncation operation helped avoid a data inconsistency. If the data was still resident in memory in a PG_CACHED page, then the tmpfs truncation operation would reactivate that page, zero the truncated portion, and leave the page pinned in memory. More precisely, the benevolent error was that the truncation operation didn't add the reactivated page to any of the paging queues, effectively pinning the page. This page would remain pinned until the file was destroyed or the page was read or written. With this change, the page is now added to the inactive queue. Discussed with: jhb Reviewed by: kib (an earlier version) MFC after: 3 weeks
2012-01-08 20:09:26 +00:00
} else {
vm_page_free(m);
vm_page_unlock(m);
Rename VM_OBJECT_LOCK(), VM_OBJECT_UNLOCK() and VM_OBJECT_TRYLOCK() to their "write" versions. Sponsored by: EMC / Isilon storage division
2013-02-20 12:03:20 +00:00
VM_OBJECT_WUNLOCK(object);
Correct an error of omission in the implementation of the truncation operation on POSIX shared memory objects and tmpfs. Previously, neither of these modules correctly handled the case in which the new size of the object or file was not a multiple of the page size. Specifically, they did not handle partial page truncation of data stored on swap. As a result, stale data might later be returned to an application. Interestingly, a data inconsistency was less likely to occur under tmpfs than POSIX shared memory objects. The reason being that a different mistake by the tmpfs truncation operation helped avoid a data inconsistency. If the data was still resident in memory in a PG_CACHED page, then the tmpfs truncation operation would reactivate that page, zero the truncated portion, and leave the page pinned in memory. More precisely, the benevolent error was that the truncation operation didn't add the reactivated page to any of the paging queues, effectively pinning the page. This page would remain pinned until the file was destroyed or the page was read or written. With this change, the page is now added to the inactive queue. Discussed with: jhb Reviewed by: kib (an earlier version) MFC after: 3 weeks
2012-01-08 20:09:26 +00:00
return (EIO);
}
}
if (m != NULL) {
pmap_zero_page_area(m, base, PAGE_SIZE - base);
KASSERT(m->valid == VM_PAGE_BITS_ALL,
("shm_dotruncate: page %p is invalid", m));
vm_page_dirty(m);
vm_pager_page_unswapped(m);
}
}
Implement global and per-uid accounting of the anonymous memory. Add rlimit RLIMIT_SWAP that limits the amount of swap that may be reserved for the uid. The accounting information (charge) is associated with either map entry, or vm object backing the entry, assuming the object is the first one in the shadow chain and entry does not require COW. Charge is moved from entry to object on allocation of the object, e.g. during the mmap, assuming the object is allocated, or on the first page fault on the entry. It moves back to the entry on forks due to COW setup. The per-entry granularity of accounting makes the charge process fair for processes that change uid during lifetime, and decrements charge for proper uid when region is unmapped. The interface of vm_pager_allocate(9) is extended by adding struct ucred *, that is used to charge appropriate uid when allocation if performed by kernel, e.g. md(4). Several syscalls, among them is fork(2), may now return ENOMEM when global or per-uid limits are enforced. In collaboration with: pho Reviewed by: alc Approved by: re (kensmith)
2009-06-23 20:45:22 +00:00
delta = ptoa(object->size - nobjsize);
Add a new file descriptor type for IPC shared memory objects and use it to implement shm_open(2) and shm_unlink(2) in the kernel: - Each shared memory file descriptor is associated with a swap-backed vm object which provides the backing store. Each descriptor starts off with a size of zero, but the size can be altered via ftruncate(2). The shared memory file descriptors also support fstat(2). read(2), write(2), ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared memory file descriptors. - shm_open(2) and shm_unlink(2) are now implemented as system calls that manage shared memory file descriptors. The virtual namespace that maps pathnames to shared memory file descriptors is implemented as a hash table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash of the pathname. - As an extension, the constant 'SHM_ANON' may be specified in place of the path argument to shm_open(2). In this case, an unnamed shared memory file descriptor will be created similar to the IPC_PRIVATE key for shmget(2). Note that the shared memory object can still be shared among processes by sharing the file descriptor via fork(2) or sendmsg(2), but it is unnamed. This effectively serves to implement the getmemfd() idea bandied about the lists several times over the years. - The backing store for shared memory file descriptors are garbage collected when they are not referenced by any open file descriptors or the shm_open(2) virtual namespace. Submitted by: dillon, peter (previous versions) Submitted by: rwatson (I based this on his version) Reviewed by: alc (suggested converting getmemfd() to shm_open())
2008-01-08 21:58:16 +00:00
/* Toss in memory pages. */
if (nobjsize < object->size)
vm_object_page_remove(object, nobjsize, object->size,
Add a new option, OBJPR_NOTMAPPED, to vm_object_page_remove(). Passing this option to vm_object_page_remove() asserts that the specified range of pages is not mapped, or more precisely that none of these pages have any managed mappings. Thus, vm_object_page_remove() need not call pmap_remove_all() on the pages. This change not only saves time by eliminating pointless calls to pmap_remove_all(), but it also eliminates an inconsistency in the use of pmap_remove_all() versus related functions, like pmap_remove_write(). It eliminates harmless but pointless calls to pmap_remove_all() that were being performed on PG_UNMANAGED pages. Update all of the existing assertions on pmap_remove_all() to reflect this change. Reviewed by: kib
2011-06-29 16:40:41 +00:00
0);
Add a new file descriptor type for IPC shared memory objects and use it to implement shm_open(2) and shm_unlink(2) in the kernel: - Each shared memory file descriptor is associated with a swap-backed vm object which provides the backing store. Each descriptor starts off with a size of zero, but the size can be altered via ftruncate(2). The shared memory file descriptors also support fstat(2). read(2), write(2), ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared memory file descriptors. - shm_open(2) and shm_unlink(2) are now implemented as system calls that manage shared memory file descriptors. The virtual namespace that maps pathnames to shared memory file descriptors is implemented as a hash table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash of the pathname. - As an extension, the constant 'SHM_ANON' may be specified in place of the path argument to shm_open(2). In this case, an unnamed shared memory file descriptor will be created similar to the IPC_PRIVATE key for shmget(2). Note that the shared memory object can still be shared among processes by sharing the file descriptor via fork(2) or sendmsg(2), but it is unnamed. This effectively serves to implement the getmemfd() idea bandied about the lists several times over the years. - The backing store for shared memory file descriptors are garbage collected when they are not referenced by any open file descriptors or the shm_open(2) virtual namespace. Submitted by: dillon, peter (previous versions) Submitted by: rwatson (I based this on his version) Reviewed by: alc (suggested converting getmemfd() to shm_open())
2008-01-08 21:58:16 +00:00
/* Toss pages from swap. */
if (object->type == OBJT_SWAP)
Implement global and per-uid accounting of the anonymous memory. Add rlimit RLIMIT_SWAP that limits the amount of swap that may be reserved for the uid. The accounting information (charge) is associated with either map entry, or vm object backing the entry, assuming the object is the first one in the shadow chain and entry does not require COW. Charge is moved from entry to object on allocation of the object, e.g. during the mmap, assuming the object is allocated, or on the first page fault on the entry. It moves back to the entry on forks due to COW setup. The per-entry granularity of accounting makes the charge process fair for processes that change uid during lifetime, and decrements charge for proper uid when region is unmapped. The interface of vm_pager_allocate(9) is extended by adding struct ucred *, that is used to charge appropriate uid when allocation if performed by kernel, e.g. md(4). Several syscalls, among them is fork(2), may now return ENOMEM when global or per-uid limits are enforced. In collaboration with: pho Reviewed by: alc Approved by: re (kensmith)
2009-06-23 20:45:22 +00:00
swap_pager_freespace(object, nobjsize, delta);
/* Free the swap accounted for shm */
Replace pointer to "struct uidinfo" with pointer to "struct ucred" in "struct vm_object". This is required to make it possible to account for per-jail swap usage. Reviewed by: kib@ Tested by: pho@ Sponsored by: FreeBSD Foundation
2010-12-02 17:37:16 +00:00
swap_release_by_cred(delta, object->cred);
Implement global and per-uid accounting of the anonymous memory. Add rlimit RLIMIT_SWAP that limits the amount of swap that may be reserved for the uid. The accounting information (charge) is associated with either map entry, or vm object backing the entry, assuming the object is the first one in the shadow chain and entry does not require COW. Charge is moved from entry to object on allocation of the object, e.g. during the mmap, assuming the object is allocated, or on the first page fault on the entry. It moves back to the entry on forks due to COW setup. The per-entry granularity of accounting makes the charge process fair for processes that change uid during lifetime, and decrements charge for proper uid when region is unmapped. The interface of vm_pager_allocate(9) is extended by adding struct ucred *, that is used to charge appropriate uid when allocation if performed by kernel, e.g. md(4). Several syscalls, among them is fork(2), may now return ENOMEM when global or per-uid limits are enforced. In collaboration with: pho Reviewed by: alc Approved by: re (kensmith)
2009-06-23 20:45:22 +00:00
object->charge -= delta;
} else {
/* Attempt to reserve the swap */
delta = ptoa(nobjsize - object->size);
Replace pointer to "struct uidinfo" with pointer to "struct ucred" in "struct vm_object". This is required to make it possible to account for per-jail swap usage. Reviewed by: kib@ Tested by: pho@ Sponsored by: FreeBSD Foundation
2010-12-02 17:37:16 +00:00
if (!swap_reserve_by_cred(delta, object->cred)) {
Rename VM_OBJECT_LOCK(), VM_OBJECT_UNLOCK() and VM_OBJECT_TRYLOCK() to their "write" versions. Sponsored by: EMC / Isilon storage division
2013-02-20 12:03:20 +00:00
VM_OBJECT_WUNLOCK(object);
Implement global and per-uid accounting of the anonymous memory. Add rlimit RLIMIT_SWAP that limits the amount of swap that may be reserved for the uid. The accounting information (charge) is associated with either map entry, or vm object backing the entry, assuming the object is the first one in the shadow chain and entry does not require COW. Charge is moved from entry to object on allocation of the object, e.g. during the mmap, assuming the object is allocated, or on the first page fault on the entry. It moves back to the entry on forks due to COW setup. The per-entry granularity of accounting makes the charge process fair for processes that change uid during lifetime, and decrements charge for proper uid when region is unmapped. The interface of vm_pager_allocate(9) is extended by adding struct ucred *, that is used to charge appropriate uid when allocation if performed by kernel, e.g. md(4). Several syscalls, among them is fork(2), may now return ENOMEM when global or per-uid limits are enforced. In collaboration with: pho Reviewed by: alc Approved by: re (kensmith)
2009-06-23 20:45:22 +00:00
return (ENOMEM);
}
object->charge += delta;
Add a new file descriptor type for IPC shared memory objects and use it to implement shm_open(2) and shm_unlink(2) in the kernel: - Each shared memory file descriptor is associated with a swap-backed vm object which provides the backing store. Each descriptor starts off with a size of zero, but the size can be altered via ftruncate(2). The shared memory file descriptors also support fstat(2). read(2), write(2), ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared memory file descriptors. - shm_open(2) and shm_unlink(2) are now implemented as system calls that manage shared memory file descriptors. The virtual namespace that maps pathnames to shared memory file descriptors is implemented as a hash table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash of the pathname. - As an extension, the constant 'SHM_ANON' may be specified in place of the path argument to shm_open(2). In this case, an unnamed shared memory file descriptor will be created similar to the IPC_PRIVATE key for shmget(2). Note that the shared memory object can still be shared among processes by sharing the file descriptor via fork(2) or sendmsg(2), but it is unnamed. This effectively serves to implement the getmemfd() idea bandied about the lists several times over the years. - The backing store for shared memory file descriptors are garbage collected when they are not referenced by any open file descriptors or the shm_open(2) virtual namespace. Submitted by: dillon, peter (previous versions) Submitted by: rwatson (I based this on his version) Reviewed by: alc (suggested converting getmemfd() to shm_open())
2008-01-08 21:58:16 +00:00
}
shmfd->shm_size = length;
mtx_lock(&shm_timestamp_lock);
vfs_timestamp(&shmfd->shm_ctime);
shmfd->shm_mtime = shmfd->shm_ctime;
mtx_unlock(&shm_timestamp_lock);
object->size = nobjsize;
Rename VM_OBJECT_LOCK(), VM_OBJECT_UNLOCK() and VM_OBJECT_TRYLOCK() to their "write" versions. Sponsored by: EMC / Isilon storage division
2013-02-20 12:03:20 +00:00
VM_OBJECT_WUNLOCK(object);
Implement global and per-uid accounting of the anonymous memory. Add rlimit RLIMIT_SWAP that limits the amount of swap that may be reserved for the uid. The accounting information (charge) is associated with either map entry, or vm object backing the entry, assuming the object is the first one in the shadow chain and entry does not require COW. Charge is moved from entry to object on allocation of the object, e.g. during the mmap, assuming the object is allocated, or on the first page fault on the entry. It moves back to the entry on forks due to COW setup. The per-entry granularity of accounting makes the charge process fair for processes that change uid during lifetime, and decrements charge for proper uid when region is unmapped. The interface of vm_pager_allocate(9) is extended by adding struct ucred *, that is used to charge appropriate uid when allocation if performed by kernel, e.g. md(4). Several syscalls, among them is fork(2), may now return ENOMEM when global or per-uid limits are enforced. In collaboration with: pho Reviewed by: alc Approved by: re (kensmith)
2009-06-23 20:45:22 +00:00
return (0);
Add a new file descriptor type for IPC shared memory objects and use it to implement shm_open(2) and shm_unlink(2) in the kernel: - Each shared memory file descriptor is associated with a swap-backed vm object which provides the backing store. Each descriptor starts off with a size of zero, but the size can be altered via ftruncate(2). The shared memory file descriptors also support fstat(2). read(2), write(2), ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared memory file descriptors. - shm_open(2) and shm_unlink(2) are now implemented as system calls that manage shared memory file descriptors. The virtual namespace that maps pathnames to shared memory file descriptors is implemented as a hash table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash of the pathname. - As an extension, the constant 'SHM_ANON' may be specified in place of the path argument to shm_open(2). In this case, an unnamed shared memory file descriptor will be created similar to the IPC_PRIVATE key for shmget(2). Note that the shared memory object can still be shared among processes by sharing the file descriptor via fork(2) or sendmsg(2), but it is unnamed. This effectively serves to implement the getmemfd() idea bandied about the lists several times over the years. - The backing store for shared memory file descriptors are garbage collected when they are not referenced by any open file descriptors or the shm_open(2) virtual namespace. Submitted by: dillon, peter (previous versions) Submitted by: rwatson (I based this on his version) Reviewed by: alc (suggested converting getmemfd() to shm_open())
2008-01-08 21:58:16 +00:00
}
/*
* shmfd object management including creation and reference counting
* routines.
*/
static struct shmfd *
shm_alloc(struct ucred *ucred, mode_t mode)
{
struct shmfd *shmfd;
Use a unit number allocator to provide suitable st_dev and st_ino values for POSIX shared memory descriptors. The implementation is similar to that used for pipes. MFC after: 1 week
2014-08-29 18:18:29 +00:00
int ino;
Add a new file descriptor type for IPC shared memory objects and use it to implement shm_open(2) and shm_unlink(2) in the kernel: - Each shared memory file descriptor is associated with a swap-backed vm object which provides the backing store. Each descriptor starts off with a size of zero, but the size can be altered via ftruncate(2). The shared memory file descriptors also support fstat(2). read(2), write(2), ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared memory file descriptors. - shm_open(2) and shm_unlink(2) are now implemented as system calls that manage shared memory file descriptors. The virtual namespace that maps pathnames to shared memory file descriptors is implemented as a hash table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash of the pathname. - As an extension, the constant 'SHM_ANON' may be specified in place of the path argument to shm_open(2). In this case, an unnamed shared memory file descriptor will be created similar to the IPC_PRIVATE key for shmget(2). Note that the shared memory object can still be shared among processes by sharing the file descriptor via fork(2) or sendmsg(2), but it is unnamed. This effectively serves to implement the getmemfd() idea bandied about the lists several times over the years. - The backing store for shared memory file descriptors are garbage collected when they are not referenced by any open file descriptors or the shm_open(2) virtual namespace. Submitted by: dillon, peter (previous versions) Submitted by: rwatson (I based this on his version) Reviewed by: alc (suggested converting getmemfd() to shm_open())
2008-01-08 21:58:16 +00:00
shmfd = malloc(sizeof(*shmfd), M_SHMFD, M_WAITOK | M_ZERO);
shmfd->shm_size = 0;
shmfd->shm_uid = ucred->cr_uid;
shmfd->shm_gid = ucred->cr_gid;
shmfd->shm_mode = mode;
shmfd->shm_object = vm_pager_allocate(OBJT_DEFAULT, NULL,
Implement global and per-uid accounting of the anonymous memory. Add rlimit RLIMIT_SWAP that limits the amount of swap that may be reserved for the uid. The accounting information (charge) is associated with either map entry, or vm object backing the entry, assuming the object is the first one in the shadow chain and entry does not require COW. Charge is moved from entry to object on allocation of the object, e.g. during the mmap, assuming the object is allocated, or on the first page fault on the entry. It moves back to the entry on forks due to COW setup. The per-entry granularity of accounting makes the charge process fair for processes that change uid during lifetime, and decrements charge for proper uid when region is unmapped. The interface of vm_pager_allocate(9) is extended by adding struct ucred *, that is used to charge appropriate uid when allocation if performed by kernel, e.g. md(4). Several syscalls, among them is fork(2), may now return ENOMEM when global or per-uid limits are enforced. In collaboration with: pho Reviewed by: alc Approved by: re (kensmith)
2009-06-23 20:45:22 +00:00
shmfd->shm_size, VM_PROT_DEFAULT, 0, ucred);
Add a new file descriptor type for IPC shared memory objects and use it to implement shm_open(2) and shm_unlink(2) in the kernel: - Each shared memory file descriptor is associated with a swap-backed vm object which provides the backing store. Each descriptor starts off with a size of zero, but the size can be altered via ftruncate(2). The shared memory file descriptors also support fstat(2). read(2), write(2), ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared memory file descriptors. - shm_open(2) and shm_unlink(2) are now implemented as system calls that manage shared memory file descriptors. The virtual namespace that maps pathnames to shared memory file descriptors is implemented as a hash table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash of the pathname. - As an extension, the constant 'SHM_ANON' may be specified in place of the path argument to shm_open(2). In this case, an unnamed shared memory file descriptor will be created similar to the IPC_PRIVATE key for shmget(2). Note that the shared memory object can still be shared among processes by sharing the file descriptor via fork(2) or sendmsg(2), but it is unnamed. This effectively serves to implement the getmemfd() idea bandied about the lists several times over the years. - The backing store for shared memory file descriptors are garbage collected when they are not referenced by any open file descriptors or the shm_open(2) virtual namespace. Submitted by: dillon, peter (previous versions) Submitted by: rwatson (I based this on his version) Reviewed by: alc (suggested converting getmemfd() to shm_open())
2008-01-08 21:58:16 +00:00
KASSERT(shmfd->shm_object != NULL, ("shm_create: vm_pager_allocate"));
Preset the object's color, or alignment, to maximize superpage usage. MFC after: 5 days
2015-02-08 21:00:51 +00:00
shmfd->shm_object->pg_color = 0;
Rename VM_OBJECT_LOCK(), VM_OBJECT_UNLOCK() and VM_OBJECT_TRYLOCK() to their "write" versions. Sponsored by: EMC / Isilon storage division
2013-02-20 12:03:20 +00:00
VM_OBJECT_WLOCK(shmfd->shm_object);
Initialize the vm object's flags to include OBJ_NOSPLIT, just like the vm objects that are used by System V shared memory segments.
2008-04-13 21:08:34 +00:00
vm_object_clear_flag(shmfd->shm_object, OBJ_ONEMAPPING);
Preset the object's color, or alignment, to maximize superpage usage. MFC after: 5 days
2015-02-08 21:00:51 +00:00
vm_object_set_flag(shmfd->shm_object, OBJ_COLORED | OBJ_NOSPLIT);
Rename VM_OBJECT_LOCK(), VM_OBJECT_UNLOCK() and VM_OBJECT_TRYLOCK() to their "write" versions. Sponsored by: EMC / Isilon storage division
2013-02-20 12:03:20 +00:00
VM_OBJECT_WUNLOCK(shmfd->shm_object);
Add a new file descriptor type for IPC shared memory objects and use it to implement shm_open(2) and shm_unlink(2) in the kernel: - Each shared memory file descriptor is associated with a swap-backed vm object which provides the backing store. Each descriptor starts off with a size of zero, but the size can be altered via ftruncate(2). The shared memory file descriptors also support fstat(2). read(2), write(2), ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared memory file descriptors. - shm_open(2) and shm_unlink(2) are now implemented as system calls that manage shared memory file descriptors. The virtual namespace that maps pathnames to shared memory file descriptors is implemented as a hash table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash of the pathname. - As an extension, the constant 'SHM_ANON' may be specified in place of the path argument to shm_open(2). In this case, an unnamed shared memory file descriptor will be created similar to the IPC_PRIVATE key for shmget(2). Note that the shared memory object can still be shared among processes by sharing the file descriptor via fork(2) or sendmsg(2), but it is unnamed. This effectively serves to implement the getmemfd() idea bandied about the lists several times over the years. - The backing store for shared memory file descriptors are garbage collected when they are not referenced by any open file descriptors or the shm_open(2) virtual namespace. Submitted by: dillon, peter (previous versions) Submitted by: rwatson (I based this on his version) Reviewed by: alc (suggested converting getmemfd() to shm_open())
2008-01-08 21:58:16 +00:00
vfs_timestamp(&shmfd->shm_birthtime);
shmfd->shm_atime = shmfd->shm_mtime = shmfd->shm_ctime =
shmfd->shm_birthtime;
Use a unit number allocator to provide suitable st_dev and st_ino values for POSIX shared memory descriptors. The implementation is similar to that used for pipes. MFC after: 1 week
2014-08-29 18:18:29 +00:00
ino = alloc_unr(shm_ino_unr);
if (ino == -1)
shmfd->shm_ino = 0;
else
shmfd->shm_ino = ino;
Add a new file descriptor type for IPC shared memory objects and use it to implement shm_open(2) and shm_unlink(2) in the kernel: - Each shared memory file descriptor is associated with a swap-backed vm object which provides the backing store. Each descriptor starts off with a size of zero, but the size can be altered via ftruncate(2). The shared memory file descriptors also support fstat(2). read(2), write(2), ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared memory file descriptors. - shm_open(2) and shm_unlink(2) are now implemented as system calls that manage shared memory file descriptors. The virtual namespace that maps pathnames to shared memory file descriptors is implemented as a hash table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash of the pathname. - As an extension, the constant 'SHM_ANON' may be specified in place of the path argument to shm_open(2). In this case, an unnamed shared memory file descriptor will be created similar to the IPC_PRIVATE key for shmget(2). Note that the shared memory object can still be shared among processes by sharing the file descriptor via fork(2) or sendmsg(2), but it is unnamed. This effectively serves to implement the getmemfd() idea bandied about the lists several times over the years. - The backing store for shared memory file descriptors are garbage collected when they are not referenced by any open file descriptors or the shm_open(2) virtual namespace. Submitted by: dillon, peter (previous versions) Submitted by: rwatson (I based this on his version) Reviewed by: alc (suggested converting getmemfd() to shm_open())
2008-01-08 21:58:16 +00:00
refcount_init(&shmfd->shm_refs, 1);
Implement read(2)/write(2) and neccessary lseek(2) for posix shmfd. Add MAC framework entries for posix shm read and write. Do not allow implicit extension of the underlying memory segment past the limit set by ftruncate(2) by either of the syscalls. Read and write returns short i/o, lseek(2) fails with EINVAL when resulting offset does not fit into the limit. Discussed with: alc Tested by: pho Sponsored by: The FreeBSD Foundation
2013-08-21 17:45:00 +00:00
mtx_init(&shmfd->shm_mtx, "shmrl", NULL, MTX_DEF);
rangelock_init(&shmfd->shm_rl);
Add a new file descriptor type for IPC shared memory objects and use it to implement shm_open(2) and shm_unlink(2) in the kernel: - Each shared memory file descriptor is associated with a swap-backed vm object which provides the backing store. Each descriptor starts off with a size of zero, but the size can be altered via ftruncate(2). The shared memory file descriptors also support fstat(2). read(2), write(2), ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared memory file descriptors. - shm_open(2) and shm_unlink(2) are now implemented as system calls that manage shared memory file descriptors. The virtual namespace that maps pathnames to shared memory file descriptors is implemented as a hash table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash of the pathname. - As an extension, the constant 'SHM_ANON' may be specified in place of the path argument to shm_open(2). In this case, an unnamed shared memory file descriptor will be created similar to the IPC_PRIVATE key for shmget(2). Note that the shared memory object can still be shared among processes by sharing the file descriptor via fork(2) or sendmsg(2), but it is unnamed. This effectively serves to implement the getmemfd() idea bandied about the lists several times over the years. - The backing store for shared memory file descriptors are garbage collected when they are not referenced by any open file descriptors or the shm_open(2) virtual namespace. Submitted by: dillon, peter (previous versions) Submitted by: rwatson (I based this on his version) Reviewed by: alc (suggested converting getmemfd() to shm_open())
2008-01-08 21:58:16 +00:00
#ifdef MAC
mac_posixshm_init(shmfd);
mac_posixshm_create(ucred, shmfd);
#endif
return (shmfd);
}
static struct shmfd *
shm_hold(struct shmfd *shmfd)
{
refcount_acquire(&shmfd->shm_refs);
return (shmfd);
}
static void
shm_drop(struct shmfd *shmfd)
{
if (refcount_release(&shmfd->shm_refs)) {
#ifdef MAC
mac_posixshm_destroy(shmfd);
#endif
Implement read(2)/write(2) and neccessary lseek(2) for posix shmfd. Add MAC framework entries for posix shm read and write. Do not allow implicit extension of the underlying memory segment past the limit set by ftruncate(2) by either of the syscalls. Read and write returns short i/o, lseek(2) fails with EINVAL when resulting offset does not fit into the limit. Discussed with: alc Tested by: pho Sponsored by: The FreeBSD Foundation
2013-08-21 17:45:00 +00:00
rangelock_destroy(&shmfd->shm_rl);
mtx_destroy(&shmfd->shm_mtx);
Add a new file descriptor type for IPC shared memory objects and use it to implement shm_open(2) and shm_unlink(2) in the kernel: - Each shared memory file descriptor is associated with a swap-backed vm object which provides the backing store. Each descriptor starts off with a size of zero, but the size can be altered via ftruncate(2). The shared memory file descriptors also support fstat(2). read(2), write(2), ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared memory file descriptors. - shm_open(2) and shm_unlink(2) are now implemented as system calls that manage shared memory file descriptors. The virtual namespace that maps pathnames to shared memory file descriptors is implemented as a hash table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash of the pathname. - As an extension, the constant 'SHM_ANON' may be specified in place of the path argument to shm_open(2). In this case, an unnamed shared memory file descriptor will be created similar to the IPC_PRIVATE key for shmget(2). Note that the shared memory object can still be shared among processes by sharing the file descriptor via fork(2) or sendmsg(2), but it is unnamed. This effectively serves to implement the getmemfd() idea bandied about the lists several times over the years. - The backing store for shared memory file descriptors are garbage collected when they are not referenced by any open file descriptors or the shm_open(2) virtual namespace. Submitted by: dillon, peter (previous versions) Submitted by: rwatson (I based this on his version) Reviewed by: alc (suggested converting getmemfd() to shm_open())
2008-01-08 21:58:16 +00:00
vm_object_deallocate(shmfd->shm_object);
Use a unit number allocator to provide suitable st_dev and st_ino values for POSIX shared memory descriptors. The implementation is similar to that used for pipes. MFC after: 1 week
2014-08-29 18:18:29 +00:00
if (shmfd->shm_ino != 0)
free_unr(shm_ino_unr, shmfd->shm_ino);
Add a new file descriptor type for IPC shared memory objects and use it to implement shm_open(2) and shm_unlink(2) in the kernel: - Each shared memory file descriptor is associated with a swap-backed vm object which provides the backing store. Each descriptor starts off with a size of zero, but the size can be altered via ftruncate(2). The shared memory file descriptors also support fstat(2). read(2), write(2), ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared memory file descriptors. - shm_open(2) and shm_unlink(2) are now implemented as system calls that manage shared memory file descriptors. The virtual namespace that maps pathnames to shared memory file descriptors is implemented as a hash table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash of the pathname. - As an extension, the constant 'SHM_ANON' may be specified in place of the path argument to shm_open(2). In this case, an unnamed shared memory file descriptor will be created similar to the IPC_PRIVATE key for shmget(2). Note that the shared memory object can still be shared among processes by sharing the file descriptor via fork(2) or sendmsg(2), but it is unnamed. This effectively serves to implement the getmemfd() idea bandied about the lists several times over the years. - The backing store for shared memory file descriptors are garbage collected when they are not referenced by any open file descriptors or the shm_open(2) virtual namespace. Submitted by: dillon, peter (previous versions) Submitted by: rwatson (I based this on his version) Reviewed by: alc (suggested converting getmemfd() to shm_open())
2008-01-08 21:58:16 +00:00
free(shmfd, M_SHMFD);
}
}
/*
* Determine if the credentials have sufficient permissions for a
* specified combination of FREAD and FWRITE.
*/
static int
shm_access(struct shmfd *shmfd, struct ucred *ucred, int flags)
{
Introduce accmode_t. This is required for NFSv4 ACLs - it will be neccessary to add more V* constants, and the variables changed by this patch were often being assigned to mode_t variables, which is 16 bit. Approved by: rwatson (mentor)
2008-10-28 13:44:11 +00:00
accmode_t accmode;
Add the fo_chown and fo_chmod methods to struct fileops and use them to implement fchown(2) and fchmod(2) support for several file types that previously lacked it. Add MAC entries for chown/chmod done on posix shared memory and (old) in-kernel posix semaphores. Based on the submission by: glebius Reviewed by: rwatson Approved by: re (bz)
2011-08-16 20:07:47 +00:00
int error;
Add a new file descriptor type for IPC shared memory objects and use it to implement shm_open(2) and shm_unlink(2) in the kernel: - Each shared memory file descriptor is associated with a swap-backed vm object which provides the backing store. Each descriptor starts off with a size of zero, but the size can be altered via ftruncate(2). The shared memory file descriptors also support fstat(2). read(2), write(2), ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared memory file descriptors. - shm_open(2) and shm_unlink(2) are now implemented as system calls that manage shared memory file descriptors. The virtual namespace that maps pathnames to shared memory file descriptors is implemented as a hash table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash of the pathname. - As an extension, the constant 'SHM_ANON' may be specified in place of the path argument to shm_open(2). In this case, an unnamed shared memory file descriptor will be created similar to the IPC_PRIVATE key for shmget(2). Note that the shared memory object can still be shared among processes by sharing the file descriptor via fork(2) or sendmsg(2), but it is unnamed. This effectively serves to implement the getmemfd() idea bandied about the lists several times over the years. - The backing store for shared memory file descriptors are garbage collected when they are not referenced by any open file descriptors or the shm_open(2) virtual namespace. Submitted by: dillon, peter (previous versions) Submitted by: rwatson (I based this on his version) Reviewed by: alc (suggested converting getmemfd() to shm_open())
2008-01-08 21:58:16 +00:00
Introduce accmode_t. This is required for NFSv4 ACLs - it will be neccessary to add more V* constants, and the variables changed by this patch were often being assigned to mode_t variables, which is 16 bit. Approved by: rwatson (mentor)
2008-10-28 13:44:11 +00:00
accmode = 0;
Add a new file descriptor type for IPC shared memory objects and use it to implement shm_open(2) and shm_unlink(2) in the kernel: - Each shared memory file descriptor is associated with a swap-backed vm object which provides the backing store. Each descriptor starts off with a size of zero, but the size can be altered via ftruncate(2). The shared memory file descriptors also support fstat(2). read(2), write(2), ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared memory file descriptors. - shm_open(2) and shm_unlink(2) are now implemented as system calls that manage shared memory file descriptors. The virtual namespace that maps pathnames to shared memory file descriptors is implemented as a hash table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash of the pathname. - As an extension, the constant 'SHM_ANON' may be specified in place of the path argument to shm_open(2). In this case, an unnamed shared memory file descriptor will be created similar to the IPC_PRIVATE key for shmget(2). Note that the shared memory object can still be shared among processes by sharing the file descriptor via fork(2) or sendmsg(2), but it is unnamed. This effectively serves to implement the getmemfd() idea bandied about the lists several times over the years. - The backing store for shared memory file descriptors are garbage collected when they are not referenced by any open file descriptors or the shm_open(2) virtual namespace. Submitted by: dillon, peter (previous versions) Submitted by: rwatson (I based this on his version) Reviewed by: alc (suggested converting getmemfd() to shm_open())
2008-01-08 21:58:16 +00:00
if (flags & FREAD)
Introduce accmode_t. This is required for NFSv4 ACLs - it will be neccessary to add more V* constants, and the variables changed by this patch were often being assigned to mode_t variables, which is 16 bit. Approved by: rwatson (mentor)
2008-10-28 13:44:11 +00:00
accmode |= VREAD;
Add a new file descriptor type for IPC shared memory objects and use it to implement shm_open(2) and shm_unlink(2) in the kernel: - Each shared memory file descriptor is associated with a swap-backed vm object which provides the backing store. Each descriptor starts off with a size of zero, but the size can be altered via ftruncate(2). The shared memory file descriptors also support fstat(2). read(2), write(2), ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared memory file descriptors. - shm_open(2) and shm_unlink(2) are now implemented as system calls that manage shared memory file descriptors. The virtual namespace that maps pathnames to shared memory file descriptors is implemented as a hash table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash of the pathname. - As an extension, the constant 'SHM_ANON' may be specified in place of the path argument to shm_open(2). In this case, an unnamed shared memory file descriptor will be created similar to the IPC_PRIVATE key for shmget(2). Note that the shared memory object can still be shared among processes by sharing the file descriptor via fork(2) or sendmsg(2), but it is unnamed. This effectively serves to implement the getmemfd() idea bandied about the lists several times over the years. - The backing store for shared memory file descriptors are garbage collected when they are not referenced by any open file descriptors or the shm_open(2) virtual namespace. Submitted by: dillon, peter (previous versions) Submitted by: rwatson (I based this on his version) Reviewed by: alc (suggested converting getmemfd() to shm_open())
2008-01-08 21:58:16 +00:00
if (flags & FWRITE)
Introduce accmode_t. This is required for NFSv4 ACLs - it will be neccessary to add more V* constants, and the variables changed by this patch were often being assigned to mode_t variables, which is 16 bit. Approved by: rwatson (mentor)
2008-10-28 13:44:11 +00:00
accmode |= VWRITE;
Add the fo_chown and fo_chmod methods to struct fileops and use them to implement fchown(2) and fchmod(2) support for several file types that previously lacked it. Add MAC entries for chown/chmod done on posix shared memory and (old) in-kernel posix semaphores. Based on the submission by: glebius Reviewed by: rwatson Approved by: re (bz)
2011-08-16 20:07:47 +00:00
mtx_lock(&shm_timestamp_lock);
error = vaccess(VREG, shmfd->shm_mode, shmfd->shm_uid, shmfd->shm_gid,
accmode, ucred, NULL);
mtx_unlock(&shm_timestamp_lock);
return (error);
Add a new file descriptor type for IPC shared memory objects and use it to implement shm_open(2) and shm_unlink(2) in the kernel: - Each shared memory file descriptor is associated with a swap-backed vm object which provides the backing store. Each descriptor starts off with a size of zero, but the size can be altered via ftruncate(2). The shared memory file descriptors also support fstat(2). read(2), write(2), ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared memory file descriptors. - shm_open(2) and shm_unlink(2) are now implemented as system calls that manage shared memory file descriptors. The virtual namespace that maps pathnames to shared memory file descriptors is implemented as a hash table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash of the pathname. - As an extension, the constant 'SHM_ANON' may be specified in place of the path argument to shm_open(2). In this case, an unnamed shared memory file descriptor will be created similar to the IPC_PRIVATE key for shmget(2). Note that the shared memory object can still be shared among processes by sharing the file descriptor via fork(2) or sendmsg(2), but it is unnamed. This effectively serves to implement the getmemfd() idea bandied about the lists several times over the years. - The backing store for shared memory file descriptors are garbage collected when they are not referenced by any open file descriptors or the shm_open(2) virtual namespace. Submitted by: dillon, peter (previous versions) Submitted by: rwatson (I based this on his version) Reviewed by: alc (suggested converting getmemfd() to shm_open())
2008-01-08 21:58:16 +00:00
}
/*
* Dictionary management. We maintain an in-kernel dictionary to map
* paths to shmfd objects. We use the FNV hash on the path to store
* the mappings in a hash table.
*/
static void
Use a unit number allocator to provide suitable st_dev and st_ino values for POSIX shared memory descriptors. The implementation is similar to that used for pipes. MFC after: 1 week
2014-08-29 18:18:29 +00:00
shm_init(void *arg)
Add a new file descriptor type for IPC shared memory objects and use it to implement shm_open(2) and shm_unlink(2) in the kernel: - Each shared memory file descriptor is associated with a swap-backed vm object which provides the backing store. Each descriptor starts off with a size of zero, but the size can be altered via ftruncate(2). The shared memory file descriptors also support fstat(2). read(2), write(2), ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared memory file descriptors. - shm_open(2) and shm_unlink(2) are now implemented as system calls that manage shared memory file descriptors. The virtual namespace that maps pathnames to shared memory file descriptors is implemented as a hash table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash of the pathname. - As an extension, the constant 'SHM_ANON' may be specified in place of the path argument to shm_open(2). In this case, an unnamed shared memory file descriptor will be created similar to the IPC_PRIVATE key for shmget(2). Note that the shared memory object can still be shared among processes by sharing the file descriptor via fork(2) or sendmsg(2), but it is unnamed. This effectively serves to implement the getmemfd() idea bandied about the lists several times over the years. - The backing store for shared memory file descriptors are garbage collected when they are not referenced by any open file descriptors or the shm_open(2) virtual namespace. Submitted by: dillon, peter (previous versions) Submitted by: rwatson (I based this on his version) Reviewed by: alc (suggested converting getmemfd() to shm_open())
2008-01-08 21:58:16 +00:00
{
mtx_init(&shm_timestamp_lock, "shm timestamps", NULL, MTX_DEF);
sx_init(&shm_dict_lock, "shm dictionary");
shm_dictionary = hashinit(1024, M_SHMFD, &shm_hash);
Use a unit number allocator to provide suitable st_dev and st_ino values for POSIX shared memory descriptors. The implementation is similar to that used for pipes. MFC after: 1 week
2014-08-29 18:18:29 +00:00
shm_ino_unr = new_unrhdr(1, INT32_MAX, NULL);
KASSERT(shm_ino_unr != NULL, ("shm fake inodes not initialized"));
shm_dev_ino = devfs_alloc_cdp_inode();
KASSERT(shm_dev_ino > 0, ("shm dev inode not initialized"));
Add a new file descriptor type for IPC shared memory objects and use it to implement shm_open(2) and shm_unlink(2) in the kernel: - Each shared memory file descriptor is associated with a swap-backed vm object which provides the backing store. Each descriptor starts off with a size of zero, but the size can be altered via ftruncate(2). The shared memory file descriptors also support fstat(2). read(2), write(2), ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared memory file descriptors. - shm_open(2) and shm_unlink(2) are now implemented as system calls that manage shared memory file descriptors. The virtual namespace that maps pathnames to shared memory file descriptors is implemented as a hash table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash of the pathname. - As an extension, the constant 'SHM_ANON' may be specified in place of the path argument to shm_open(2). In this case, an unnamed shared memory file descriptor will be created similar to the IPC_PRIVATE key for shmget(2). Note that the shared memory object can still be shared among processes by sharing the file descriptor via fork(2) or sendmsg(2), but it is unnamed. This effectively serves to implement the getmemfd() idea bandied about the lists several times over the years. - The backing store for shared memory file descriptors are garbage collected when they are not referenced by any open file descriptors or the shm_open(2) virtual namespace. Submitted by: dillon, peter (previous versions) Submitted by: rwatson (I based this on his version) Reviewed by: alc (suggested converting getmemfd() to shm_open())
2008-01-08 21:58:16 +00:00
}
Use a unit number allocator to provide suitable st_dev and st_ino values for POSIX shared memory descriptors. The implementation is similar to that used for pipes. MFC after: 1 week
2014-08-29 18:18:29 +00:00
SYSINIT(shm_init, SI_SUB_SYSV_SHM, SI_ORDER_ANY, shm_init, NULL);
Add a new file descriptor type for IPC shared memory objects and use it to implement shm_open(2) and shm_unlink(2) in the kernel: - Each shared memory file descriptor is associated with a swap-backed vm object which provides the backing store. Each descriptor starts off with a size of zero, but the size can be altered via ftruncate(2). The shared memory file descriptors also support fstat(2). read(2), write(2), ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared memory file descriptors. - shm_open(2) and shm_unlink(2) are now implemented as system calls that manage shared memory file descriptors. The virtual namespace that maps pathnames to shared memory file descriptors is implemented as a hash table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash of the pathname. - As an extension, the constant 'SHM_ANON' may be specified in place of the path argument to shm_open(2). In this case, an unnamed shared memory file descriptor will be created similar to the IPC_PRIVATE key for shmget(2). Note that the shared memory object can still be shared among processes by sharing the file descriptor via fork(2) or sendmsg(2), but it is unnamed. This effectively serves to implement the getmemfd() idea bandied about the lists several times over the years. - The backing store for shared memory file descriptors are garbage collected when they are not referenced by any open file descriptors or the shm_open(2) virtual namespace. Submitted by: dillon, peter (previous versions) Submitted by: rwatson (I based this on his version) Reviewed by: alc (suggested converting getmemfd() to shm_open())
2008-01-08 21:58:16 +00:00
static struct shmfd *
shm_lookup(char *path, Fnv32_t fnv)
{
struct shm_mapping *map;
LIST_FOREACH(map, SHM_HASH(fnv), sm_link) {
if (map->sm_fnv != fnv)
continue;
if (strcmp(map->sm_path, path) == 0)
return (map->sm_shmfd);
}
return (NULL);
}
static void
shm_insert(char *path, Fnv32_t fnv, struct shmfd *shmfd)
{
struct shm_mapping *map;
map = malloc(sizeof(struct shm_mapping), M_SHMFD, M_WAITOK);
map->sm_path = path;
map->sm_fnv = fnv;
map->sm_shmfd = shm_hold(shmfd);
Export some more useful info about shared memory objects to userland via procstat(1) and fstat(1): - Change shm file descriptors to track the pathname they are associated with and add a shm_path() method to copy the path out to a caller-supplied buffer. - Use the fo_stat() method of shared memory objects and shm_path() to export the path, mode, and size of a shared memory object via struct kinfo_file. - Add a struct shmstat to the libprocstat(3) interface along with a procstat_get_shm_info() to export the mode and size of a shared memory object. - Change procstat to always print out the path for a given object if it is valid. - Teach fstat about shared memory objects and to display their path, mode, and size. MFC after: 2 weeks
2012-04-01 18:22:48 +00:00
shmfd->shm_path = path;
Add a new file descriptor type for IPC shared memory objects and use it to implement shm_open(2) and shm_unlink(2) in the kernel: - Each shared memory file descriptor is associated with a swap-backed vm object which provides the backing store. Each descriptor starts off with a size of zero, but the size can be altered via ftruncate(2). The shared memory file descriptors also support fstat(2). read(2), write(2), ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared memory file descriptors. - shm_open(2) and shm_unlink(2) are now implemented as system calls that manage shared memory file descriptors. The virtual namespace that maps pathnames to shared memory file descriptors is implemented as a hash table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash of the pathname. - As an extension, the constant 'SHM_ANON' may be specified in place of the path argument to shm_open(2). In this case, an unnamed shared memory file descriptor will be created similar to the IPC_PRIVATE key for shmget(2). Note that the shared memory object can still be shared among processes by sharing the file descriptor via fork(2) or sendmsg(2), but it is unnamed. This effectively serves to implement the getmemfd() idea bandied about the lists several times over the years. - The backing store for shared memory file descriptors are garbage collected when they are not referenced by any open file descriptors or the shm_open(2) virtual namespace. Submitted by: dillon, peter (previous versions) Submitted by: rwatson (I based this on his version) Reviewed by: alc (suggested converting getmemfd() to shm_open())
2008-01-08 21:58:16 +00:00
LIST_INSERT_HEAD(SHM_HASH(fnv), map, sm_link);
}
static int
shm_remove(char *path, Fnv32_t fnv, struct ucred *ucred)
{
struct shm_mapping *map;
int error;
LIST_FOREACH(map, SHM_HASH(fnv), sm_link) {
if (map->sm_fnv != fnv)
continue;
if (strcmp(map->sm_path, path) == 0) {
#ifdef MAC
error = mac_posixshm_check_unlink(ucred, map->sm_shmfd);
if (error)
return (error);
#endif
error = shm_access(map->sm_shmfd, ucred,
FREAD | FWRITE);
if (error)
return (error);
Export some more useful info about shared memory objects to userland via procstat(1) and fstat(1): - Change shm file descriptors to track the pathname they are associated with and add a shm_path() method to copy the path out to a caller-supplied buffer. - Use the fo_stat() method of shared memory objects and shm_path() to export the path, mode, and size of a shared memory object via struct kinfo_file. - Add a struct shmstat to the libprocstat(3) interface along with a procstat_get_shm_info() to export the mode and size of a shared memory object. - Change procstat to always print out the path for a given object if it is valid. - Teach fstat about shared memory objects and to display their path, mode, and size. MFC after: 2 weeks
2012-04-01 18:22:48 +00:00
map->sm_shmfd->shm_path = NULL;
Add a new file descriptor type for IPC shared memory objects and use it to implement shm_open(2) and shm_unlink(2) in the kernel: - Each shared memory file descriptor is associated with a swap-backed vm object which provides the backing store. Each descriptor starts off with a size of zero, but the size can be altered via ftruncate(2). The shared memory file descriptors also support fstat(2). read(2), write(2), ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared memory file descriptors. - shm_open(2) and shm_unlink(2) are now implemented as system calls that manage shared memory file descriptors. The virtual namespace that maps pathnames to shared memory file descriptors is implemented as a hash table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash of the pathname. - As an extension, the constant 'SHM_ANON' may be specified in place of the path argument to shm_open(2). In this case, an unnamed shared memory file descriptor will be created similar to the IPC_PRIVATE key for shmget(2). Note that the shared memory object can still be shared among processes by sharing the file descriptor via fork(2) or sendmsg(2), but it is unnamed. This effectively serves to implement the getmemfd() idea bandied about the lists several times over the years. - The backing store for shared memory file descriptors are garbage collected when they are not referenced by any open file descriptors or the shm_open(2) virtual namespace. Submitted by: dillon, peter (previous versions) Submitted by: rwatson (I based this on his version) Reviewed by: alc (suggested converting getmemfd() to shm_open())
2008-01-08 21:58:16 +00:00
LIST_REMOVE(map, sm_link);
shm_drop(map->sm_shmfd);
free(map->sm_path, M_SHMFD);
free(map, M_SHMFD);
return (0);
}
}
return (ENOENT);
}
int
Add kern_shm_open(). This allows you to specify the capabilities that the new file descriptor should have. This allows us to create shared memory objects that only have the rights we're interested in. The idea behind restricting the rights is that it makes it a lot easier for CloudABI to get consistent behaviour across different operating systems. We only need to make sure that a shared memory implementation consistently implements the operations that are whitelisted. Approved by: kib Obtained from: https://github.com/NuxiNL/freebsd
2015-08-01 07:21:14 +00:00
kern_shm_open(struct thread *td, const char *userpath, int flags, mode_t mode,
struct filecaps *fcaps)
Add a new file descriptor type for IPC shared memory objects and use it to implement shm_open(2) and shm_unlink(2) in the kernel: - Each shared memory file descriptor is associated with a swap-backed vm object which provides the backing store. Each descriptor starts off with a size of zero, but the size can be altered via ftruncate(2). The shared memory file descriptors also support fstat(2). read(2), write(2), ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared memory file descriptors. - shm_open(2) and shm_unlink(2) are now implemented as system calls that manage shared memory file descriptors. The virtual namespace that maps pathnames to shared memory file descriptors is implemented as a hash table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash of the pathname. - As an extension, the constant 'SHM_ANON' may be specified in place of the path argument to shm_open(2). In this case, an unnamed shared memory file descriptor will be created similar to the IPC_PRIVATE key for shmget(2). Note that the shared memory object can still be shared among processes by sharing the file descriptor via fork(2) or sendmsg(2), but it is unnamed. This effectively serves to implement the getmemfd() idea bandied about the lists several times over the years. - The backing store for shared memory file descriptors are garbage collected when they are not referenced by any open file descriptors or the shm_open(2) virtual namespace. Submitted by: dillon, peter (previous versions) Submitted by: rwatson (I based this on his version) Reviewed by: alc (suggested converting getmemfd() to shm_open())
2008-01-08 21:58:16 +00:00
{
struct filedesc *fdp;
struct shmfd *shmfd;
struct file *fp;
char *path;
Fnv32_t fnv;
mode_t cmode;
int fd, error;
Add some checks to ensure that Capsicum is behaving correctly, and add some more explicit comments about what's going on and what future maintainers need to do when e.g. adding a new operation to a sys_machdep.c. Approved by: mentor(rwatson), re(bz)
2011-06-30 10:56:02 +00:00
#ifdef CAPABILITY_MODE
/*
* shm_open(2) is only allowed for anonymous objects.
*/
Add kern_shm_open(). This allows you to specify the capabilities that the new file descriptor should have. This allows us to create shared memory objects that only have the rights we're interested in. The idea behind restricting the rights is that it makes it a lot easier for CloudABI to get consistent behaviour across different operating systems. We only need to make sure that a shared memory implementation consistently implements the operations that are whitelisted. Approved by: kib Obtained from: https://github.com/NuxiNL/freebsd
2015-08-01 07:21:14 +00:00
if (IN_CAPABILITY_MODE(td) && (userpath != SHM_ANON))
Add some checks to ensure that Capsicum is behaving correctly, and add some more explicit comments about what's going on and what future maintainers need to do when e.g. adding a new operation to a sys_machdep.c. Approved by: mentor(rwatson), re(bz)
2011-06-30 10:56:02 +00:00
return (ECAPMODE);
#endif
Add kern_shm_open(). This allows you to specify the capabilities that the new file descriptor should have. This allows us to create shared memory objects that only have the rights we're interested in. The idea behind restricting the rights is that it makes it a lot easier for CloudABI to get consistent behaviour across different operating systems. We only need to make sure that a shared memory implementation consistently implements the operations that are whitelisted. Approved by: kib Obtained from: https://github.com/NuxiNL/freebsd
2015-08-01 07:21:14 +00:00
if ((flags & O_ACCMODE) != O_RDONLY && (flags & O_ACCMODE) != O_RDWR)
Add a new file descriptor type for IPC shared memory objects and use it to implement shm_open(2) and shm_unlink(2) in the kernel: - Each shared memory file descriptor is associated with a swap-backed vm object which provides the backing store. Each descriptor starts off with a size of zero, but the size can be altered via ftruncate(2). The shared memory file descriptors also support fstat(2). read(2), write(2), ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared memory file descriptors. - shm_open(2) and shm_unlink(2) are now implemented as system calls that manage shared memory file descriptors. The virtual namespace that maps pathnames to shared memory file descriptors is implemented as a hash table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash of the pathname. - As an extension, the constant 'SHM_ANON' may be specified in place of the path argument to shm_open(2). In this case, an unnamed shared memory file descriptor will be created similar to the IPC_PRIVATE key for shmget(2). Note that the shared memory object can still be shared among processes by sharing the file descriptor via fork(2) or sendmsg(2), but it is unnamed. This effectively serves to implement the getmemfd() idea bandied about the lists several times over the years. - The backing store for shared memory file descriptors are garbage collected when they are not referenced by any open file descriptors or the shm_open(2) virtual namespace. Submitted by: dillon, peter (previous versions) Submitted by: rwatson (I based this on his version) Reviewed by: alc (suggested converting getmemfd() to shm_open())
2008-01-08 21:58:16 +00:00
return (EINVAL);
Add kern_shm_open(). This allows you to specify the capabilities that the new file descriptor should have. This allows us to create shared memory objects that only have the rights we're interested in. The idea behind restricting the rights is that it makes it a lot easier for CloudABI to get consistent behaviour across different operating systems. We only need to make sure that a shared memory implementation consistently implements the operations that are whitelisted. Approved by: kib Obtained from: https://github.com/NuxiNL/freebsd
2015-08-01 07:21:14 +00:00
if ((flags & ~(O_ACCMODE | O_CREAT | O_EXCL | O_TRUNC | O_CLOEXEC)) != 0)
Add a new file descriptor type for IPC shared memory objects and use it to implement shm_open(2) and shm_unlink(2) in the kernel: - Each shared memory file descriptor is associated with a swap-backed vm object which provides the backing store. Each descriptor starts off with a size of zero, but the size can be altered via ftruncate(2). The shared memory file descriptors also support fstat(2). read(2), write(2), ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared memory file descriptors. - shm_open(2) and shm_unlink(2) are now implemented as system calls that manage shared memory file descriptors. The virtual namespace that maps pathnames to shared memory file descriptors is implemented as a hash table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash of the pathname. - As an extension, the constant 'SHM_ANON' may be specified in place of the path argument to shm_open(2). In this case, an unnamed shared memory file descriptor will be created similar to the IPC_PRIVATE key for shmget(2). Note that the shared memory object can still be shared among processes by sharing the file descriptor via fork(2) or sendmsg(2), but it is unnamed. This effectively serves to implement the getmemfd() idea bandied about the lists several times over the years. - The backing store for shared memory file descriptors are garbage collected when they are not referenced by any open file descriptors or the shm_open(2) virtual namespace. Submitted by: dillon, peter (previous versions) Submitted by: rwatson (I based this on his version) Reviewed by: alc (suggested converting getmemfd() to shm_open())
2008-01-08 21:58:16 +00:00
return (EINVAL);
fdp = td->td_proc->p_fd;
Add kern_shm_open(). This allows you to specify the capabilities that the new file descriptor should have. This allows us to create shared memory objects that only have the rights we're interested in. The idea behind restricting the rights is that it makes it a lot easier for CloudABI to get consistent behaviour across different operating systems. We only need to make sure that a shared memory implementation consistently implements the operations that are whitelisted. Approved by: kib Obtained from: https://github.com/NuxiNL/freebsd
2015-08-01 07:21:14 +00:00
cmode = (mode & ~fdp->fd_cmask) & ACCESSPERMS;
Add a new file descriptor type for IPC shared memory objects and use it to implement shm_open(2) and shm_unlink(2) in the kernel: - Each shared memory file descriptor is associated with a swap-backed vm object which provides the backing store. Each descriptor starts off with a size of zero, but the size can be altered via ftruncate(2). The shared memory file descriptors also support fstat(2). read(2), write(2), ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared memory file descriptors. - shm_open(2) and shm_unlink(2) are now implemented as system calls that manage shared memory file descriptors. The virtual namespace that maps pathnames to shared memory file descriptors is implemented as a hash table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash of the pathname. - As an extension, the constant 'SHM_ANON' may be specified in place of the path argument to shm_open(2). In this case, an unnamed shared memory file descriptor will be created similar to the IPC_PRIVATE key for shmget(2). Note that the shared memory object can still be shared among processes by sharing the file descriptor via fork(2) or sendmsg(2), but it is unnamed. This effectively serves to implement the getmemfd() idea bandied about the lists several times over the years. - The backing store for shared memory file descriptors are garbage collected when they are not referenced by any open file descriptors or the shm_open(2) virtual namespace. Submitted by: dillon, peter (previous versions) Submitted by: rwatson (I based this on his version) Reviewed by: alc (suggested converting getmemfd() to shm_open())
2008-01-08 21:58:16 +00:00
Add kern_shm_open(). This allows you to specify the capabilities that the new file descriptor should have. This allows us to create shared memory objects that only have the rights we're interested in. The idea behind restricting the rights is that it makes it a lot easier for CloudABI to get consistent behaviour across different operating systems. We only need to make sure that a shared memory implementation consistently implements the operations that are whitelisted. Approved by: kib Obtained from: https://github.com/NuxiNL/freebsd
2015-08-01 07:21:14 +00:00
error = falloc_caps(td, &fp, &fd, O_CLOEXEC, fcaps);
Add a new file descriptor type for IPC shared memory objects and use it to implement shm_open(2) and shm_unlink(2) in the kernel: - Each shared memory file descriptor is associated with a swap-backed vm object which provides the backing store. Each descriptor starts off with a size of zero, but the size can be altered via ftruncate(2). The shared memory file descriptors also support fstat(2). read(2), write(2), ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared memory file descriptors. - shm_open(2) and shm_unlink(2) are now implemented as system calls that manage shared memory file descriptors. The virtual namespace that maps pathnames to shared memory file descriptors is implemented as a hash table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash of the pathname. - As an extension, the constant 'SHM_ANON' may be specified in place of the path argument to shm_open(2). In this case, an unnamed shared memory file descriptor will be created similar to the IPC_PRIVATE key for shmget(2). Note that the shared memory object can still be shared among processes by sharing the file descriptor via fork(2) or sendmsg(2), but it is unnamed. This effectively serves to implement the getmemfd() idea bandied about the lists several times over the years. - The backing store for shared memory file descriptors are garbage collected when they are not referenced by any open file descriptors or the shm_open(2) virtual namespace. Submitted by: dillon, peter (previous versions) Submitted by: rwatson (I based this on his version) Reviewed by: alc (suggested converting getmemfd() to shm_open())
2008-01-08 21:58:16 +00:00
if (error)
return (error);
/* A SHM_ANON path pointer creates an anonymous object. */
Add kern_shm_open(). This allows you to specify the capabilities that the new file descriptor should have. This allows us to create shared memory objects that only have the rights we're interested in. The idea behind restricting the rights is that it makes it a lot easier for CloudABI to get consistent behaviour across different operating systems. We only need to make sure that a shared memory implementation consistently implements the operations that are whitelisted. Approved by: kib Obtained from: https://github.com/NuxiNL/freebsd
2015-08-01 07:21:14 +00:00
if (userpath == SHM_ANON) {
Add a new file descriptor type for IPC shared memory objects and use it to implement shm_open(2) and shm_unlink(2) in the kernel: - Each shared memory file descriptor is associated with a swap-backed vm object which provides the backing store. Each descriptor starts off with a size of zero, but the size can be altered via ftruncate(2). The shared memory file descriptors also support fstat(2). read(2), write(2), ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared memory file descriptors. - shm_open(2) and shm_unlink(2) are now implemented as system calls that manage shared memory file descriptors. The virtual namespace that maps pathnames to shared memory file descriptors is implemented as a hash table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash of the pathname. - As an extension, the constant 'SHM_ANON' may be specified in place of the path argument to shm_open(2). In this case, an unnamed shared memory file descriptor will be created similar to the IPC_PRIVATE key for shmget(2). Note that the shared memory object can still be shared among processes by sharing the file descriptor via fork(2) or sendmsg(2), but it is unnamed. This effectively serves to implement the getmemfd() idea bandied about the lists several times over the years. - The backing store for shared memory file descriptors are garbage collected when they are not referenced by any open file descriptors or the shm_open(2) virtual namespace. Submitted by: dillon, peter (previous versions) Submitted by: rwatson (I based this on his version) Reviewed by: alc (suggested converting getmemfd() to shm_open())
2008-01-08 21:58:16 +00:00
/* A read-only anonymous object is pointless. */
Add kern_shm_open(). This allows you to specify the capabilities that the new file descriptor should have. This allows us to create shared memory objects that only have the rights we're interested in. The idea behind restricting the rights is that it makes it a lot easier for CloudABI to get consistent behaviour across different operating systems. We only need to make sure that a shared memory implementation consistently implements the operations that are whitelisted. Approved by: kib Obtained from: https://github.com/NuxiNL/freebsd
2015-08-01 07:21:14 +00:00
if ((flags & O_ACCMODE) == O_RDONLY) {
fd: remove filedesc argument from fdclose Just accept a thread instead. This makes it consistent with fdalloc. No functional changes.
2015-04-11 15:40:28 +00:00
fdclose(td, fp, fd);
Add a new file descriptor type for IPC shared memory objects and use it to implement shm_open(2) and shm_unlink(2) in the kernel: - Each shared memory file descriptor is associated with a swap-backed vm object which provides the backing store. Each descriptor starts off with a size of zero, but the size can be altered via ftruncate(2). The shared memory file descriptors also support fstat(2). read(2), write(2), ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared memory file descriptors. - shm_open(2) and shm_unlink(2) are now implemented as system calls that manage shared memory file descriptors. The virtual namespace that maps pathnames to shared memory file descriptors is implemented as a hash table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash of the pathname. - As an extension, the constant 'SHM_ANON' may be specified in place of the path argument to shm_open(2). In this case, an unnamed shared memory file descriptor will be created similar to the IPC_PRIVATE key for shmget(2). Note that the shared memory object can still be shared among processes by sharing the file descriptor via fork(2) or sendmsg(2), but it is unnamed. This effectively serves to implement the getmemfd() idea bandied about the lists several times over the years. - The backing store for shared memory file descriptors are garbage collected when they are not referenced by any open file descriptors or the shm_open(2) virtual namespace. Submitted by: dillon, peter (previous versions) Submitted by: rwatson (I based this on his version) Reviewed by: alc (suggested converting getmemfd() to shm_open())
2008-01-08 21:58:16 +00:00
fdrop(fp, td);
return (EINVAL);
}
shmfd = shm_alloc(td->td_ucred, cmode);
} else {
path = malloc(MAXPATHLEN, M_SHMFD, M_WAITOK);
Add kern_shm_open(). This allows you to specify the capabilities that the new file descriptor should have. This allows us to create shared memory objects that only have the rights we're interested in. The idea behind restricting the rights is that it makes it a lot easier for CloudABI to get consistent behaviour across different operating systems. We only need to make sure that a shared memory implementation consistently implements the operations that are whitelisted. Approved by: kib Obtained from: https://github.com/NuxiNL/freebsd
2015-08-01 07:21:14 +00:00
error = copyinstr(userpath, path, MAXPATHLEN, NULL);
In the shm_open() and shm_unlink() syscalls, export the path to KTR. MFC after: 1 week
2014-08-01 23:29:04 +00:00
#ifdef KTRACE
if (error == 0 && KTRPOINT(curthread, KTR_NAMEI))
ktrnamei(path);
#endif
Add a new file descriptor type for IPC shared memory objects and use it to implement shm_open(2) and shm_unlink(2) in the kernel: - Each shared memory file descriptor is associated with a swap-backed vm object which provides the backing store. Each descriptor starts off with a size of zero, but the size can be altered via ftruncate(2). The shared memory file descriptors also support fstat(2). read(2), write(2), ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared memory file descriptors. - shm_open(2) and shm_unlink(2) are now implemented as system calls that manage shared memory file descriptors. The virtual namespace that maps pathnames to shared memory file descriptors is implemented as a hash table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash of the pathname. - As an extension, the constant 'SHM_ANON' may be specified in place of the path argument to shm_open(2). In this case, an unnamed shared memory file descriptor will be created similar to the IPC_PRIVATE key for shmget(2). Note that the shared memory object can still be shared among processes by sharing the file descriptor via fork(2) or sendmsg(2), but it is unnamed. This effectively serves to implement the getmemfd() idea bandied about the lists several times over the years. - The backing store for shared memory file descriptors are garbage collected when they are not referenced by any open file descriptors or the shm_open(2) virtual namespace. Submitted by: dillon, peter (previous versions) Submitted by: rwatson (I based this on his version) Reviewed by: alc (suggested converting getmemfd() to shm_open())
2008-01-08 21:58:16 +00:00
/* Require paths to start with a '/' character. */
if (error == 0 && path[0] != '/')
error = EINVAL;
if (error) {
fd: remove filedesc argument from fdclose Just accept a thread instead. This makes it consistent with fdalloc. No functional changes.
2015-04-11 15:40:28 +00:00
fdclose(td, fp, fd);
Add a new file descriptor type for IPC shared memory objects and use it to implement shm_open(2) and shm_unlink(2) in the kernel: - Each shared memory file descriptor is associated with a swap-backed vm object which provides the backing store. Each descriptor starts off with a size of zero, but the size can be altered via ftruncate(2). The shared memory file descriptors also support fstat(2). read(2), write(2), ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared memory file descriptors. - shm_open(2) and shm_unlink(2) are now implemented as system calls that manage shared memory file descriptors. The virtual namespace that maps pathnames to shared memory file descriptors is implemented as a hash table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash of the pathname. - As an extension, the constant 'SHM_ANON' may be specified in place of the path argument to shm_open(2). In this case, an unnamed shared memory file descriptor will be created similar to the IPC_PRIVATE key for shmget(2). Note that the shared memory object can still be shared among processes by sharing the file descriptor via fork(2) or sendmsg(2), but it is unnamed. This effectively serves to implement the getmemfd() idea bandied about the lists several times over the years. - The backing store for shared memory file descriptors are garbage collected when they are not referenced by any open file descriptors or the shm_open(2) virtual namespace. Submitted by: dillon, peter (previous versions) Submitted by: rwatson (I based this on his version) Reviewed by: alc (suggested converting getmemfd() to shm_open())
2008-01-08 21:58:16 +00:00
fdrop(fp, td);
free(path, M_SHMFD);
return (error);
}
fnv = fnv_32_str(path, FNV1_32_INIT);
sx_xlock(&shm_dict_lock);
shmfd = shm_lookup(path, fnv);
if (shmfd == NULL) {
/* Object does not yet exist, create it if requested. */
Add kern_shm_open(). This allows you to specify the capabilities that the new file descriptor should have. This allows us to create shared memory objects that only have the rights we're interested in. The idea behind restricting the rights is that it makes it a lot easier for CloudABI to get consistent behaviour across different operating systems. We only need to make sure that a shared memory implementation consistently implements the operations that are whitelisted. Approved by: kib Obtained from: https://github.com/NuxiNL/freebsd
2015-08-01 07:21:14 +00:00
if (flags & O_CREAT) {
Correct several issues in the integration of POSIX shared memory objects and the new setmode and setowner fileops in FreeBSD 9.0: - Add new MAC Framework entry point mac_posixshm_check_create() to allow MAC policies to authorise shared memory use. Provide a stub policy and test policy templates. - Add missing Biba and MLS implementations of mac_posixshm_check_setmode() and mac_posixshm_check_setowner(). - Add 'accmode' argument to mac_posixshm_check_open() -- unlike the mac_posixsem_check_open() entry point it was modeled on, the access mode is required as shared memory access can be read-only as well as writable; this isn't true of POSIX semaphores. - Implement full range of POSIX shared memory entry points for Biba and MLS. Sponsored by: Google Inc. Obtained from: TrustedBSD Project Approved by: re (kib)
2011-09-02 17:40:39 +00:00
#ifdef MAC
error = mac_posixshm_check_create(td->td_ucred,
path);
if (error == 0) {
#endif
shmfd = shm_alloc(td->td_ucred, cmode);
shm_insert(path, fnv, shmfd);
#ifdef MAC
}
#endif
Add a new file descriptor type for IPC shared memory objects and use it to implement shm_open(2) and shm_unlink(2) in the kernel: - Each shared memory file descriptor is associated with a swap-backed vm object which provides the backing store. Each descriptor starts off with a size of zero, but the size can be altered via ftruncate(2). The shared memory file descriptors also support fstat(2). read(2), write(2), ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared memory file descriptors. - shm_open(2) and shm_unlink(2) are now implemented as system calls that manage shared memory file descriptors. The virtual namespace that maps pathnames to shared memory file descriptors is implemented as a hash table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash of the pathname. - As an extension, the constant 'SHM_ANON' may be specified in place of the path argument to shm_open(2). In this case, an unnamed shared memory file descriptor will be created similar to the IPC_PRIVATE key for shmget(2). Note that the shared memory object can still be shared among processes by sharing the file descriptor via fork(2) or sendmsg(2), but it is unnamed. This effectively serves to implement the getmemfd() idea bandied about the lists several times over the years. - The backing store for shared memory file descriptors are garbage collected when they are not referenced by any open file descriptors or the shm_open(2) virtual namespace. Submitted by: dillon, peter (previous versions) Submitted by: rwatson (I based this on his version) Reviewed by: alc (suggested converting getmemfd() to shm_open())
2008-01-08 21:58:16 +00:00
} else {
free(path, M_SHMFD);
error = ENOENT;
}
} else {
/*
* Object already exists, obtain a new
* reference if requested and permitted.
*/
free(path, M_SHMFD);
Add kern_shm_open(). This allows you to specify the capabilities that the new file descriptor should have. This allows us to create shared memory objects that only have the rights we're interested in. The idea behind restricting the rights is that it makes it a lot easier for CloudABI to get consistent behaviour across different operating systems. We only need to make sure that a shared memory implementation consistently implements the operations that are whitelisted. Approved by: kib Obtained from: https://github.com/NuxiNL/freebsd
2015-08-01 07:21:14 +00:00
if ((flags & (O_CREAT | O_EXCL)) == (O_CREAT | O_EXCL))
Add a new file descriptor type for IPC shared memory objects and use it to implement shm_open(2) and shm_unlink(2) in the kernel: - Each shared memory file descriptor is associated with a swap-backed vm object which provides the backing store. Each descriptor starts off with a size of zero, but the size can be altered via ftruncate(2). The shared memory file descriptors also support fstat(2). read(2), write(2), ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared memory file descriptors. - shm_open(2) and shm_unlink(2) are now implemented as system calls that manage shared memory file descriptors. The virtual namespace that maps pathnames to shared memory file descriptors is implemented as a hash table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash of the pathname. - As an extension, the constant 'SHM_ANON' may be specified in place of the path argument to shm_open(2). In this case, an unnamed shared memory file descriptor will be created similar to the IPC_PRIVATE key for shmget(2). Note that the shared memory object can still be shared among processes by sharing the file descriptor via fork(2) or sendmsg(2), but it is unnamed. This effectively serves to implement the getmemfd() idea bandied about the lists several times over the years. - The backing store for shared memory file descriptors are garbage collected when they are not referenced by any open file descriptors or the shm_open(2) virtual namespace. Submitted by: dillon, peter (previous versions) Submitted by: rwatson (I based this on his version) Reviewed by: alc (suggested converting getmemfd() to shm_open())
2008-01-08 21:58:16 +00:00
error = EEXIST;
else {
#ifdef MAC
error = mac_posixshm_check_open(td->td_ucred,
Add kern_shm_open(). This allows you to specify the capabilities that the new file descriptor should have. This allows us to create shared memory objects that only have the rights we're interested in. The idea behind restricting the rights is that it makes it a lot easier for CloudABI to get consistent behaviour across different operating systems. We only need to make sure that a shared memory implementation consistently implements the operations that are whitelisted. Approved by: kib Obtained from: https://github.com/NuxiNL/freebsd
2015-08-01 07:21:14 +00:00
shmfd, FFLAGS(flags & O_ACCMODE));
Add a new file descriptor type for IPC shared memory objects and use it to implement shm_open(2) and shm_unlink(2) in the kernel: - Each shared memory file descriptor is associated with a swap-backed vm object which provides the backing store. Each descriptor starts off with a size of zero, but the size can be altered via ftruncate(2). The shared memory file descriptors also support fstat(2). read(2), write(2), ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared memory file descriptors. - shm_open(2) and shm_unlink(2) are now implemented as system calls that manage shared memory file descriptors. The virtual namespace that maps pathnames to shared memory file descriptors is implemented as a hash table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash of the pathname. - As an extension, the constant 'SHM_ANON' may be specified in place of the path argument to shm_open(2). In this case, an unnamed shared memory file descriptor will be created similar to the IPC_PRIVATE key for shmget(2). Note that the shared memory object can still be shared among processes by sharing the file descriptor via fork(2) or sendmsg(2), but it is unnamed. This effectively serves to implement the getmemfd() idea bandied about the lists several times over the years. - The backing store for shared memory file descriptors are garbage collected when they are not referenced by any open file descriptors or the shm_open(2) virtual namespace. Submitted by: dillon, peter (previous versions) Submitted by: rwatson (I based this on his version) Reviewed by: alc (suggested converting getmemfd() to shm_open())
2008-01-08 21:58:16 +00:00
if (error == 0)
#endif
error = shm_access(shmfd, td->td_ucred,
Add kern_shm_open(). This allows you to specify the capabilities that the new file descriptor should have. This allows us to create shared memory objects that only have the rights we're interested in. The idea behind restricting the rights is that it makes it a lot easier for CloudABI to get consistent behaviour across different operating systems. We only need to make sure that a shared memory implementation consistently implements the operations that are whitelisted. Approved by: kib Obtained from: https://github.com/NuxiNL/freebsd
2015-08-01 07:21:14 +00:00
FFLAGS(flags & O_ACCMODE));
Add a new file descriptor type for IPC shared memory objects and use it to implement shm_open(2) and shm_unlink(2) in the kernel: - Each shared memory file descriptor is associated with a swap-backed vm object which provides the backing store. Each descriptor starts off with a size of zero, but the size can be altered via ftruncate(2). The shared memory file descriptors also support fstat(2). read(2), write(2), ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared memory file descriptors. - shm_open(2) and shm_unlink(2) are now implemented as system calls that manage shared memory file descriptors. The virtual namespace that maps pathnames to shared memory file descriptors is implemented as a hash table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash of the pathname. - As an extension, the constant 'SHM_ANON' may be specified in place of the path argument to shm_open(2). In this case, an unnamed shared memory file descriptor will be created similar to the IPC_PRIVATE key for shmget(2). Note that the shared memory object can still be shared among processes by sharing the file descriptor via fork(2) or sendmsg(2), but it is unnamed. This effectively serves to implement the getmemfd() idea bandied about the lists several times over the years. - The backing store for shared memory file descriptors are garbage collected when they are not referenced by any open file descriptors or the shm_open(2) virtual namespace. Submitted by: dillon, peter (previous versions) Submitted by: rwatson (I based this on his version) Reviewed by: alc (suggested converting getmemfd() to shm_open())
2008-01-08 21:58:16 +00:00
}
/*
* Truncate the file back to zero length if
* O_TRUNC was specified and the object was
* opened with read/write.
*/
if (error == 0 &&
Add kern_shm_open(). This allows you to specify the capabilities that the new file descriptor should have. This allows us to create shared memory objects that only have the rights we're interested in. The idea behind restricting the rights is that it makes it a lot easier for CloudABI to get consistent behaviour across different operating systems. We only need to make sure that a shared memory implementation consistently implements the operations that are whitelisted. Approved by: kib Obtained from: https://github.com/NuxiNL/freebsd
2015-08-01 07:21:14 +00:00
(flags & (O_ACCMODE | O_TRUNC)) ==
Add a new file descriptor type for IPC shared memory objects and use it to implement shm_open(2) and shm_unlink(2) in the kernel: - Each shared memory file descriptor is associated with a swap-backed vm object which provides the backing store. Each descriptor starts off with a size of zero, but the size can be altered via ftruncate(2). The shared memory file descriptors also support fstat(2). read(2), write(2), ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared memory file descriptors. - shm_open(2) and shm_unlink(2) are now implemented as system calls that manage shared memory file descriptors. The virtual namespace that maps pathnames to shared memory file descriptors is implemented as a hash table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash of the pathname. - As an extension, the constant 'SHM_ANON' may be specified in place of the path argument to shm_open(2). In this case, an unnamed shared memory file descriptor will be created similar to the IPC_PRIVATE key for shmget(2). Note that the shared memory object can still be shared among processes by sharing the file descriptor via fork(2) or sendmsg(2), but it is unnamed. This effectively serves to implement the getmemfd() idea bandied about the lists several times over the years. - The backing store for shared memory file descriptors are garbage collected when they are not referenced by any open file descriptors or the shm_open(2) virtual namespace. Submitted by: dillon, peter (previous versions) Submitted by: rwatson (I based this on his version) Reviewed by: alc (suggested converting getmemfd() to shm_open())
2008-01-08 21:58:16 +00:00
(O_RDWR | O_TRUNC)) {
#ifdef MAC
error = mac_posixshm_check_truncate(
td->td_ucred, fp->f_cred, shmfd);
if (error == 0)
#endif
shm_dotruncate(shmfd, 0);
}
if (error == 0)
shm_hold(shmfd);
}
sx_xunlock(&shm_dict_lock);
if (error) {
fd: remove filedesc argument from fdclose Just accept a thread instead. This makes it consistent with fdalloc. No functional changes.
2015-04-11 15:40:28 +00:00
fdclose(td, fp, fd);
Add a new file descriptor type for IPC shared memory objects and use it to implement shm_open(2) and shm_unlink(2) in the kernel: - Each shared memory file descriptor is associated with a swap-backed vm object which provides the backing store. Each descriptor starts off with a size of zero, but the size can be altered via ftruncate(2). The shared memory file descriptors also support fstat(2). read(2), write(2), ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared memory file descriptors. - shm_open(2) and shm_unlink(2) are now implemented as system calls that manage shared memory file descriptors. The virtual namespace that maps pathnames to shared memory file descriptors is implemented as a hash table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash of the pathname. - As an extension, the constant 'SHM_ANON' may be specified in place of the path argument to shm_open(2). In this case, an unnamed shared memory file descriptor will be created similar to the IPC_PRIVATE key for shmget(2). Note that the shared memory object can still be shared among processes by sharing the file descriptor via fork(2) or sendmsg(2), but it is unnamed. This effectively serves to implement the getmemfd() idea bandied about the lists several times over the years. - The backing store for shared memory file descriptors are garbage collected when they are not referenced by any open file descriptors or the shm_open(2) virtual namespace. Submitted by: dillon, peter (previous versions) Submitted by: rwatson (I based this on his version) Reviewed by: alc (suggested converting getmemfd() to shm_open())
2008-01-08 21:58:16 +00:00
fdrop(fp, td);
return (error);
}
}
Add kern_shm_open(). This allows you to specify the capabilities that the new file descriptor should have. This allows us to create shared memory objects that only have the rights we're interested in. The idea behind restricting the rights is that it makes it a lot easier for CloudABI to get consistent behaviour across different operating systems. We only need to make sure that a shared memory implementation consistently implements the operations that are whitelisted. Approved by: kib Obtained from: https://github.com/NuxiNL/freebsd
2015-08-01 07:21:14 +00:00
finit(fp, FFLAGS(flags & O_ACCMODE), DTYPE_SHM, shmfd, &shm_ops);
Add a new file descriptor type for IPC shared memory objects and use it to implement shm_open(2) and shm_unlink(2) in the kernel: - Each shared memory file descriptor is associated with a swap-backed vm object which provides the backing store. Each descriptor starts off with a size of zero, but the size can be altered via ftruncate(2). The shared memory file descriptors also support fstat(2). read(2), write(2), ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared memory file descriptors. - shm_open(2) and shm_unlink(2) are now implemented as system calls that manage shared memory file descriptors. The virtual namespace that maps pathnames to shared memory file descriptors is implemented as a hash table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash of the pathname. - As an extension, the constant 'SHM_ANON' may be specified in place of the path argument to shm_open(2). In this case, an unnamed shared memory file descriptor will be created similar to the IPC_PRIVATE key for shmget(2). Note that the shared memory object can still be shared among processes by sharing the file descriptor via fork(2) or sendmsg(2), but it is unnamed. This effectively serves to implement the getmemfd() idea bandied about the lists several times over the years. - The backing store for shared memory file descriptors are garbage collected when they are not referenced by any open file descriptors or the shm_open(2) virtual namespace. Submitted by: dillon, peter (previous versions) Submitted by: rwatson (I based this on his version) Reviewed by: alc (suggested converting getmemfd() to shm_open())
2008-01-08 21:58:16 +00:00
td->td_retval[0] = fd;
fdrop(fp, td);
return (0);
}
Add kern_shm_open(). This allows you to specify the capabilities that the new file descriptor should have. This allows us to create shared memory objects that only have the rights we're interested in. The idea behind restricting the rights is that it makes it a lot easier for CloudABI to get consistent behaviour across different operating systems. We only need to make sure that a shared memory implementation consistently implements the operations that are whitelisted. Approved by: kib Obtained from: https://github.com/NuxiNL/freebsd
2015-08-01 07:21:14 +00:00
/* System calls. */
int
sys_shm_open(struct thread *td, struct shm_open_args *uap)
{
return (kern_shm_open(td, uap->path, uap->flags, uap->mode, NULL));
}
Add a new file descriptor type for IPC shared memory objects and use it to implement shm_open(2) and shm_unlink(2) in the kernel: - Each shared memory file descriptor is associated with a swap-backed vm object which provides the backing store. Each descriptor starts off with a size of zero, but the size can be altered via ftruncate(2). The shared memory file descriptors also support fstat(2). read(2), write(2), ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared memory file descriptors. - shm_open(2) and shm_unlink(2) are now implemented as system calls that manage shared memory file descriptors. The virtual namespace that maps pathnames to shared memory file descriptors is implemented as a hash table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash of the pathname. - As an extension, the constant 'SHM_ANON' may be specified in place of the path argument to shm_open(2). In this case, an unnamed shared memory file descriptor will be created similar to the IPC_PRIVATE key for shmget(2). Note that the shared memory object can still be shared among processes by sharing the file descriptor via fork(2) or sendmsg(2), but it is unnamed. This effectively serves to implement the getmemfd() idea bandied about the lists several times over the years. - The backing store for shared memory file descriptors are garbage collected when they are not referenced by any open file descriptors or the shm_open(2) virtual namespace. Submitted by: dillon, peter (previous versions) Submitted by: rwatson (I based this on his version) Reviewed by: alc (suggested converting getmemfd() to shm_open())
2008-01-08 21:58:16 +00:00
int
In order to maximize the re-usability of kernel code in user space this patch modifies makesyscalls.sh to prefix all of the non-compatibility calls (e.g. not linux_, freebsd32_) with sys_ and updates the kernel entry points and all places in the code that use them. It also fixes an additional name space collision between the kernel function psignal and the libc function of the same name by renaming the kernel psignal kern_psignal(). By introducing this change now we will ease future MFCs that change syscalls. Reviewed by: rwatson Approved by: re (bz)
2011-09-16 13:58:51 +00:00
sys_shm_unlink(struct thread *td, struct shm_unlink_args *uap)
Add a new file descriptor type for IPC shared memory objects and use it to implement shm_open(2) and shm_unlink(2) in the kernel: - Each shared memory file descriptor is associated with a swap-backed vm object which provides the backing store. Each descriptor starts off with a size of zero, but the size can be altered via ftruncate(2). The shared memory file descriptors also support fstat(2). read(2), write(2), ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared memory file descriptors. - shm_open(2) and shm_unlink(2) are now implemented as system calls that manage shared memory file descriptors. The virtual namespace that maps pathnames to shared memory file descriptors is implemented as a hash table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash of the pathname. - As an extension, the constant 'SHM_ANON' may be specified in place of the path argument to shm_open(2). In this case, an unnamed shared memory file descriptor will be created similar to the IPC_PRIVATE key for shmget(2). Note that the shared memory object can still be shared among processes by sharing the file descriptor via fork(2) or sendmsg(2), but it is unnamed. This effectively serves to implement the getmemfd() idea bandied about the lists several times over the years. - The backing store for shared memory file descriptors are garbage collected when they are not referenced by any open file descriptors or the shm_open(2) virtual namespace. Submitted by: dillon, peter (previous versions) Submitted by: rwatson (I based this on his version) Reviewed by: alc (suggested converting getmemfd() to shm_open())
2008-01-08 21:58:16 +00:00
{
char *path;
Fnv32_t fnv;
int error;
path = malloc(MAXPATHLEN, M_TEMP, M_WAITOK);
error = copyinstr(uap->path, path, MAXPATHLEN, NULL);
if (error) {
free(path, M_TEMP);
return (error);
}
In the shm_open() and shm_unlink() syscalls, export the path to KTR. MFC after: 1 week
2014-08-01 23:29:04 +00:00
#ifdef KTRACE
if (KTRPOINT(curthread, KTR_NAMEI))
ktrnamei(path);
#endif
Add a new file descriptor type for IPC shared memory objects and use it to implement shm_open(2) and shm_unlink(2) in the kernel: - Each shared memory file descriptor is associated with a swap-backed vm object which provides the backing store. Each descriptor starts off with a size of zero, but the size can be altered via ftruncate(2). The shared memory file descriptors also support fstat(2). read(2), write(2), ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared memory file descriptors. - shm_open(2) and shm_unlink(2) are now implemented as system calls that manage shared memory file descriptors. The virtual namespace that maps pathnames to shared memory file descriptors is implemented as a hash table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash of the pathname. - As an extension, the constant 'SHM_ANON' may be specified in place of the path argument to shm_open(2). In this case, an unnamed shared memory file descriptor will be created similar to the IPC_PRIVATE key for shmget(2). Note that the shared memory object can still be shared among processes by sharing the file descriptor via fork(2) or sendmsg(2), but it is unnamed. This effectively serves to implement the getmemfd() idea bandied about the lists several times over the years. - The backing store for shared memory file descriptors are garbage collected when they are not referenced by any open file descriptors or the shm_open(2) virtual namespace. Submitted by: dillon, peter (previous versions) Submitted by: rwatson (I based this on his version) Reviewed by: alc (suggested converting getmemfd() to shm_open())
2008-01-08 21:58:16 +00:00
fnv = fnv_32_str(path, FNV1_32_INIT);
sx_xlock(&shm_dict_lock);
error = shm_remove(path, fnv, td->td_ucred);
sx_xunlock(&shm_dict_lock);
free(path, M_TEMP);
return (error);
}
int
Add a new file operations hook for mmap operations. File type-specific logic is now placed in the mmap hook implementation rather than requiring it to be placed in sys/vm/vm_mmap.c. This hook allows new file types to support mmap() as well as potentially allowing mmap() for existing file types that do not currently support any mapping. The vm_mmap() function is now split up into two functions. A new vm_mmap_object() function handles the "back half" of vm_mmap() and accepts a referenced VM object to map rather than a (handle, handle_type) tuple. vm_mmap() is now reduced to converting a (handle, handle_type) tuple to a a VM object and then calling vm_mmap_object() to handle the actual mapping. The vm_mmap() function remains for use by other parts of the kernel (e.g. device drivers and exec) but now only supports mapping vnodes, character devices, and anonymous memory. The mmap() system call invokes vm_mmap_object() directly with a NULL object for anonymous mappings. For mappings using a file descriptor, the descriptors fo_mmap() hook is invoked instead. The fo_mmap() hook is responsible for performing type-specific checks and adjustments to arguments as well as possibly modifying mapping parameters such as flags or the object offset. The fo_mmap() hook routines then call vm_mmap_object() to handle the actual mapping. The fo_mmap() hook is optional. If it is not set, then fo_mmap() will fail with ENODEV. A fo_mmap() hook is implemented for regular files, character devices, and shared memory objects (created via shm_open()). While here, consistently use the VM_PROT_* constants for the vm_prot_t type for the 'prot' variable passed to vm_mmap() and vm_mmap_object() as well as the vm_mmap_vnode() and vm_mmap_cdev() helper routines. Previously some places were using the mmap()-specific PROT_* constants instead. While this happens to work because PROT_xx == VM_PROT_xx, using VM_PROT_* is more correct. Differential Revision: https://reviews.freebsd.org/D2658 Reviewed by: alc (glanced over), kib MFC after: 1 month Sponsored by: Chelsio
2015-06-04 19:41:15 +00:00
shm_mmap(struct file *fp, vm_map_t map, vm_offset_t *addr, vm_size_t objsize,
vm_prot_t prot, vm_prot_t cap_maxprot, int flags,
vm_ooffset_t foff, struct thread *td)
Add a new file descriptor type for IPC shared memory objects and use it to implement shm_open(2) and shm_unlink(2) in the kernel: - Each shared memory file descriptor is associated with a swap-backed vm object which provides the backing store. Each descriptor starts off with a size of zero, but the size can be altered via ftruncate(2). The shared memory file descriptors also support fstat(2). read(2), write(2), ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared memory file descriptors. - shm_open(2) and shm_unlink(2) are now implemented as system calls that manage shared memory file descriptors. The virtual namespace that maps pathnames to shared memory file descriptors is implemented as a hash table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash of the pathname. - As an extension, the constant 'SHM_ANON' may be specified in place of the path argument to shm_open(2). In this case, an unnamed shared memory file descriptor will be created similar to the IPC_PRIVATE key for shmget(2). Note that the shared memory object can still be shared among processes by sharing the file descriptor via fork(2) or sendmsg(2), but it is unnamed. This effectively serves to implement the getmemfd() idea bandied about the lists several times over the years. - The backing store for shared memory file descriptors are garbage collected when they are not referenced by any open file descriptors or the shm_open(2) virtual namespace. Submitted by: dillon, peter (previous versions) Submitted by: rwatson (I based this on his version) Reviewed by: alc (suggested converting getmemfd() to shm_open())
2008-01-08 21:58:16 +00:00
{
Add a new file operations hook for mmap operations. File type-specific logic is now placed in the mmap hook implementation rather than requiring it to be placed in sys/vm/vm_mmap.c. This hook allows new file types to support mmap() as well as potentially allowing mmap() for existing file types that do not currently support any mapping. The vm_mmap() function is now split up into two functions. A new vm_mmap_object() function handles the "back half" of vm_mmap() and accepts a referenced VM object to map rather than a (handle, handle_type) tuple. vm_mmap() is now reduced to converting a (handle, handle_type) tuple to a a VM object and then calling vm_mmap_object() to handle the actual mapping. The vm_mmap() function remains for use by other parts of the kernel (e.g. device drivers and exec) but now only supports mapping vnodes, character devices, and anonymous memory. The mmap() system call invokes vm_mmap_object() directly with a NULL object for anonymous mappings. For mappings using a file descriptor, the descriptors fo_mmap() hook is invoked instead. The fo_mmap() hook is responsible for performing type-specific checks and adjustments to arguments as well as possibly modifying mapping parameters such as flags or the object offset. The fo_mmap() hook routines then call vm_mmap_object() to handle the actual mapping. The fo_mmap() hook is optional. If it is not set, then fo_mmap() will fail with ENODEV. A fo_mmap() hook is implemented for regular files, character devices, and shared memory objects (created via shm_open()). While here, consistently use the VM_PROT_* constants for the vm_prot_t type for the 'prot' variable passed to vm_mmap() and vm_mmap_object() as well as the vm_mmap_vnode() and vm_mmap_cdev() helper routines. Previously some places were using the mmap()-specific PROT_* constants instead. While this happens to work because PROT_xx == VM_PROT_xx, using VM_PROT_* is more correct. Differential Revision: https://reviews.freebsd.org/D2658 Reviewed by: alc (glanced over), kib MFC after: 1 month Sponsored by: Chelsio
2015-06-04 19:41:15 +00:00
struct shmfd *shmfd;
vm_prot_t maxprot;
int error;
shmfd = fp->f_data;
maxprot = VM_PROT_NONE;
/* FREAD should always be set. */
if ((fp->f_flag & FREAD) != 0)
maxprot |= VM_PROT_EXECUTE | VM_PROT_READ;
if ((fp->f_flag & FWRITE) != 0)
maxprot |= VM_PROT_WRITE;
/* Don't permit shared writable mappings on read-only descriptors. */
if ((flags & MAP_SHARED) != 0 &&
(maxprot & VM_PROT_WRITE) == 0 &&
(prot & VM_PROT_WRITE) != 0)
return (EACCES);
maxprot &= cap_maxprot;
Add a new file descriptor type for IPC shared memory objects and use it to implement shm_open(2) and shm_unlink(2) in the kernel: - Each shared memory file descriptor is associated with a swap-backed vm object which provides the backing store. Each descriptor starts off with a size of zero, but the size can be altered via ftruncate(2). The shared memory file descriptors also support fstat(2). read(2), write(2), ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared memory file descriptors. - shm_open(2) and shm_unlink(2) are now implemented as system calls that manage shared memory file descriptors. The virtual namespace that maps pathnames to shared memory file descriptors is implemented as a hash table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash of the pathname. - As an extension, the constant 'SHM_ANON' may be specified in place of the path argument to shm_open(2). In this case, an unnamed shared memory file descriptor will be created similar to the IPC_PRIVATE key for shmget(2). Note that the shared memory object can still be shared among processes by sharing the file descriptor via fork(2) or sendmsg(2), but it is unnamed. This effectively serves to implement the getmemfd() idea bandied about the lists several times over the years. - The backing store for shared memory file descriptors are garbage collected when they are not referenced by any open file descriptors or the shm_open(2) virtual namespace. Submitted by: dillon, peter (previous versions) Submitted by: rwatson (I based this on his version) Reviewed by: alc (suggested converting getmemfd() to shm_open())
2008-01-08 21:58:16 +00:00
Add a new file operations hook for mmap operations. File type-specific logic is now placed in the mmap hook implementation rather than requiring it to be placed in sys/vm/vm_mmap.c. This hook allows new file types to support mmap() as well as potentially allowing mmap() for existing file types that do not currently support any mapping. The vm_mmap() function is now split up into two functions. A new vm_mmap_object() function handles the "back half" of vm_mmap() and accepts a referenced VM object to map rather than a (handle, handle_type) tuple. vm_mmap() is now reduced to converting a (handle, handle_type) tuple to a a VM object and then calling vm_mmap_object() to handle the actual mapping. The vm_mmap() function remains for use by other parts of the kernel (e.g. device drivers and exec) but now only supports mapping vnodes, character devices, and anonymous memory. The mmap() system call invokes vm_mmap_object() directly with a NULL object for anonymous mappings. For mappings using a file descriptor, the descriptors fo_mmap() hook is invoked instead. The fo_mmap() hook is responsible for performing type-specific checks and adjustments to arguments as well as possibly modifying mapping parameters such as flags or the object offset. The fo_mmap() hook routines then call vm_mmap_object() to handle the actual mapping. The fo_mmap() hook is optional. If it is not set, then fo_mmap() will fail with ENODEV. A fo_mmap() hook is implemented for regular files, character devices, and shared memory objects (created via shm_open()). While here, consistently use the VM_PROT_* constants for the vm_prot_t type for the 'prot' variable passed to vm_mmap() and vm_mmap_object() as well as the vm_mmap_vnode() and vm_mmap_cdev() helper routines. Previously some places were using the mmap()-specific PROT_* constants instead. While this happens to work because PROT_xx == VM_PROT_xx, using VM_PROT_* is more correct. Differential Revision: https://reviews.freebsd.org/D2658 Reviewed by: alc (glanced over), kib MFC after: 1 month Sponsored by: Chelsio
2015-06-04 19:41:15 +00:00
#ifdef MAC
error = mac_posixshm_check_mmap(td->td_ucred, shmfd, prot, flags);
if (error != 0)
return (error);
#endif
Add a new file descriptor type for IPC shared memory objects and use it to implement shm_open(2) and shm_unlink(2) in the kernel: - Each shared memory file descriptor is associated with a swap-backed vm object which provides the backing store. Each descriptor starts off with a size of zero, but the size can be altered via ftruncate(2). The shared memory file descriptors also support fstat(2). read(2), write(2), ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared memory file descriptors. - shm_open(2) and shm_unlink(2) are now implemented as system calls that manage shared memory file descriptors. The virtual namespace that maps pathnames to shared memory file descriptors is implemented as a hash table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash of the pathname. - As an extension, the constant 'SHM_ANON' may be specified in place of the path argument to shm_open(2). In this case, an unnamed shared memory file descriptor will be created similar to the IPC_PRIVATE key for shmget(2). Note that the shared memory object can still be shared among processes by sharing the file descriptor via fork(2) or sendmsg(2), but it is unnamed. This effectively serves to implement the getmemfd() idea bandied about the lists several times over the years. - The backing store for shared memory file descriptors are garbage collected when they are not referenced by any open file descriptors or the shm_open(2) virtual namespace. Submitted by: dillon, peter (previous versions) Submitted by: rwatson (I based this on his version) Reviewed by: alc (suggested converting getmemfd() to shm_open())
2008-01-08 21:58:16 +00:00
/*
* XXXRW: This validation is probably insufficient, and subject to
* sign errors. It should be fixed.
*/
Shared memory objects that have size which is not necessarily equal to exact multiple of system page size should still be allowed to be mapped in their entirety to match the regular vnode backed file behavior. Reported by: ed Reviewed by: jhb
2008-12-01 22:33:50 +00:00
if (foff >= shmfd->shm_size ||
foff + objsize > round_page(shmfd->shm_size))
Add a new file descriptor type for IPC shared memory objects and use it to implement shm_open(2) and shm_unlink(2) in the kernel: - Each shared memory file descriptor is associated with a swap-backed vm object which provides the backing store. Each descriptor starts off with a size of zero, but the size can be altered via ftruncate(2). The shared memory file descriptors also support fstat(2). read(2), write(2), ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared memory file descriptors. - shm_open(2) and shm_unlink(2) are now implemented as system calls that manage shared memory file descriptors. The virtual namespace that maps pathnames to shared memory file descriptors is implemented as a hash table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash of the pathname. - As an extension, the constant 'SHM_ANON' may be specified in place of the path argument to shm_open(2). In this case, an unnamed shared memory file descriptor will be created similar to the IPC_PRIVATE key for shmget(2). Note that the shared memory object can still be shared among processes by sharing the file descriptor via fork(2) or sendmsg(2), but it is unnamed. This effectively serves to implement the getmemfd() idea bandied about the lists several times over the years. - The backing store for shared memory file descriptors are garbage collected when they are not referenced by any open file descriptors or the shm_open(2) virtual namespace. Submitted by: dillon, peter (previous versions) Submitted by: rwatson (I based this on his version) Reviewed by: alc (suggested converting getmemfd() to shm_open())
2008-01-08 21:58:16 +00:00
return (EINVAL);
mtx_lock(&shm_timestamp_lock);
vfs_timestamp(&shmfd->shm_atime);
mtx_unlock(&shm_timestamp_lock);
vm_object_reference(shmfd->shm_object);
Add a new file operations hook for mmap operations. File type-specific logic is now placed in the mmap hook implementation rather than requiring it to be placed in sys/vm/vm_mmap.c. This hook allows new file types to support mmap() as well as potentially allowing mmap() for existing file types that do not currently support any mapping. The vm_mmap() function is now split up into two functions. A new vm_mmap_object() function handles the "back half" of vm_mmap() and accepts a referenced VM object to map rather than a (handle, handle_type) tuple. vm_mmap() is now reduced to converting a (handle, handle_type) tuple to a a VM object and then calling vm_mmap_object() to handle the actual mapping. The vm_mmap() function remains for use by other parts of the kernel (e.g. device drivers and exec) but now only supports mapping vnodes, character devices, and anonymous memory. The mmap() system call invokes vm_mmap_object() directly with a NULL object for anonymous mappings. For mappings using a file descriptor, the descriptors fo_mmap() hook is invoked instead. The fo_mmap() hook is responsible for performing type-specific checks and adjustments to arguments as well as possibly modifying mapping parameters such as flags or the object offset. The fo_mmap() hook routines then call vm_mmap_object() to handle the actual mapping. The fo_mmap() hook is optional. If it is not set, then fo_mmap() will fail with ENODEV. A fo_mmap() hook is implemented for regular files, character devices, and shared memory objects (created via shm_open()). While here, consistently use the VM_PROT_* constants for the vm_prot_t type for the 'prot' variable passed to vm_mmap() and vm_mmap_object() as well as the vm_mmap_vnode() and vm_mmap_cdev() helper routines. Previously some places were using the mmap()-specific PROT_* constants instead. While this happens to work because PROT_xx == VM_PROT_xx, using VM_PROT_* is more correct. Differential Revision: https://reviews.freebsd.org/D2658 Reviewed by: alc (glanced over), kib MFC after: 1 month Sponsored by: Chelsio
2015-06-04 19:41:15 +00:00
error = vm_mmap_object(map, addr, objsize, prot, maxprot, flags,
shmfd->shm_object, foff, FALSE, td);
if (error != 0)
vm_object_deallocate(shmfd->shm_object);
Add a new file descriptor type for IPC shared memory objects and use it to implement shm_open(2) and shm_unlink(2) in the kernel: - Each shared memory file descriptor is associated with a swap-backed vm object which provides the backing store. Each descriptor starts off with a size of zero, but the size can be altered via ftruncate(2). The shared memory file descriptors also support fstat(2). read(2), write(2), ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared memory file descriptors. - shm_open(2) and shm_unlink(2) are now implemented as system calls that manage shared memory file descriptors. The virtual namespace that maps pathnames to shared memory file descriptors is implemented as a hash table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash of the pathname. - As an extension, the constant 'SHM_ANON' may be specified in place of the path argument to shm_open(2). In this case, an unnamed shared memory file descriptor will be created similar to the IPC_PRIVATE key for shmget(2). Note that the shared memory object can still be shared among processes by sharing the file descriptor via fork(2) or sendmsg(2), but it is unnamed. This effectively serves to implement the getmemfd() idea bandied about the lists several times over the years. - The backing store for shared memory file descriptors are garbage collected when they are not referenced by any open file descriptors or the shm_open(2) virtual namespace. Submitted by: dillon, peter (previous versions) Submitted by: rwatson (I based this on his version) Reviewed by: alc (suggested converting getmemfd() to shm_open())
2008-01-08 21:58:16 +00:00
return (0);
}
Add the fo_chown and fo_chmod methods to struct fileops and use them to implement fchown(2) and fchmod(2) support for several file types that previously lacked it. Add MAC entries for chown/chmod done on posix shared memory and (old) in-kernel posix semaphores. Based on the submission by: glebius Reviewed by: rwatson Approved by: re (bz)
2011-08-16 20:07:47 +00:00
static int
shm_chmod(struct file *fp, mode_t mode, struct ucred *active_cred,
struct thread *td)
{
struct shmfd *shmfd;
int error;
error = 0;
shmfd = fp->f_data;
mtx_lock(&shm_timestamp_lock);
/*
* SUSv4 says that x bits of permission need not be affected.
* Be consistent with our shm_open there.
*/
#ifdef MAC
error = mac_posixshm_check_setmode(active_cred, shmfd, mode);
if (error != 0)
goto out;
#endif
error = vaccess(VREG, shmfd->shm_mode, shmfd->shm_uid,
shmfd->shm_gid, VADMIN, active_cred, NULL);
if (error != 0)
goto out;
shmfd->shm_mode = mode & ACCESSPERMS;
out:
mtx_unlock(&shm_timestamp_lock);
return (error);
}
static int
shm_chown(struct file *fp, uid_t uid, gid_t gid, struct ucred *active_cred,
struct thread *td)
{
struct shmfd *shmfd;
int error;
Fix build breakage. Initialize error variables explicitely for !MAC case. Pointy hat to: kib Approved by: re (bz)
2011-08-17 12:37:14 +00:00
error = 0;
Add the fo_chown and fo_chmod methods to struct fileops and use them to implement fchown(2) and fchmod(2) support for several file types that previously lacked it. Add MAC entries for chown/chmod done on posix shared memory and (old) in-kernel posix semaphores. Based on the submission by: glebius Reviewed by: rwatson Approved by: re (bz)
2011-08-16 20:07:47 +00:00
shmfd = fp->f_data;
mtx_lock(&shm_timestamp_lock);
#ifdef MAC
error = mac_posixshm_check_setowner(active_cred, shmfd, uid, gid);
if (error != 0)
goto out;
#endif
if (uid == (uid_t)-1)
uid = shmfd->shm_uid;
if (gid == (gid_t)-1)
gid = shmfd->shm_gid;
if (((uid != shmfd->shm_uid && uid != active_cred->cr_uid) ||
(gid != shmfd->shm_gid && !groupmember(gid, active_cred))) &&
(error = priv_check_cred(active_cred, PRIV_VFS_CHOWN, 0)))
goto out;
shmfd->shm_uid = uid;
shmfd->shm_gid = gid;
out:
mtx_unlock(&shm_timestamp_lock);
return (error);
}
Add a helper API to allow in-kernel code to map portions of shared memory objects created by shm_open(2) into the kernel's address space. This provides a convenient way for creating shared memory buffers between userland and the kernel without requiring custom character devices.
2011-12-14 22:22:19 +00:00
/*
* Helper routines to allow the backing object of a shared memory file
* descriptor to be mapped in the kernel.
*/
int
shm_map(struct file *fp, size_t size, off_t offset, void **memp)
{
struct shmfd *shmfd;
vm_offset_t kva, ofs;
vm_object_t obj;
int rv;
if (fp->f_type != DTYPE_SHM)
return (EINVAL);
shmfd = fp->f_data;
obj = shmfd->shm_object;
Rename VM_OBJECT_LOCK(), VM_OBJECT_UNLOCK() and VM_OBJECT_TRYLOCK() to their "write" versions. Sponsored by: EMC / Isilon storage division
2013-02-20 12:03:20 +00:00
VM_OBJECT_WLOCK(obj);
Add a helper API to allow in-kernel code to map portions of shared memory objects created by shm_open(2) into the kernel's address space. This provides a convenient way for creating shared memory buffers between userland and the kernel without requiring custom character devices.
2011-12-14 22:22:19 +00:00
/*
* XXXRW: This validation is probably insufficient, and subject to
* sign errors. It should be fixed.
*/
if (offset >= shmfd->shm_size ||
offset + size > round_page(shmfd->shm_size)) {
Rename VM_OBJECT_LOCK(), VM_OBJECT_UNLOCK() and VM_OBJECT_TRYLOCK() to their "write" versions. Sponsored by: EMC / Isilon storage division
2013-02-20 12:03:20 +00:00
VM_OBJECT_WUNLOCK(obj);
Add a helper API to allow in-kernel code to map portions of shared memory objects created by shm_open(2) into the kernel's address space. This provides a convenient way for creating shared memory buffers between userland and the kernel without requiring custom character devices.
2011-12-14 22:22:19 +00:00
return (EINVAL);
}
shmfd->shm_kmappings++;
vm_object_reference_locked(obj);
Rename VM_OBJECT_LOCK(), VM_OBJECT_UNLOCK() and VM_OBJECT_TRYLOCK() to their "write" versions. Sponsored by: EMC / Isilon storage division
2013-02-20 12:03:20 +00:00
VM_OBJECT_WUNLOCK(obj);
Add a helper API to allow in-kernel code to map portions of shared memory objects created by shm_open(2) into the kernel's address space. This provides a convenient way for creating shared memory buffers between userland and the kernel without requiring custom character devices.
2011-12-14 22:22:19 +00:00
/* Map the object into the kernel_map and wire it. */
kva = vm_map_min(kernel_map);
ofs = offset & PAGE_MASK;
offset = trunc_page(offset);
size = round_page(size + ofs);
Add a mmap flag (MAP_32BIT) on 64-bit platforms to request that a mapping use an address in the first 2GB of the process's address space. This flag should have the same semantics as the same flag on Linux. To facilitate this, add a new parameter to vm_map_find() that specifies an optional maximum virtual address. While here, fix several callers of vm_map_find() to use a VMFS_* constant for the findspace argument instead of TRUE and FALSE. Reviewed by: alc Approved by: re (kib)
2013-09-09 18:11:59 +00:00
rv = vm_map_find(kernel_map, obj, offset, &kva, size, 0,
Use VMFS_OPTIMAL_SPACE instead of VMFS_ALIGNED_SPACE in shm_map().
2013-07-24 20:34:25 +00:00
VMFS_OPTIMAL_SPACE, VM_PROT_READ | VM_PROT_WRITE,
Add a helper API to allow in-kernel code to map portions of shared memory objects created by shm_open(2) into the kernel's address space. This provides a convenient way for creating shared memory buffers between userland and the kernel without requiring custom character devices.
2011-12-14 22:22:19 +00:00
VM_PROT_READ | VM_PROT_WRITE, 0);
if (rv == KERN_SUCCESS) {
rv = vm_map_wire(kernel_map, kva, kva + size,
VM_MAP_WIRE_SYSTEM | VM_MAP_WIRE_NOHOLES);
if (rv == KERN_SUCCESS) {
*memp = (void *)(kva + ofs);
return (0);
}
vm_map_remove(kernel_map, kva, kva + size);
} else
vm_object_deallocate(obj);
/* On failure, drop our mapping reference. */
Rename VM_OBJECT_LOCK(), VM_OBJECT_UNLOCK() and VM_OBJECT_TRYLOCK() to their "write" versions. Sponsored by: EMC / Isilon storage division
2013-02-20 12:03:20 +00:00
VM_OBJECT_WLOCK(obj);
Add a helper API to allow in-kernel code to map portions of shared memory objects created by shm_open(2) into the kernel's address space. This provides a convenient way for creating shared memory buffers between userland and the kernel without requiring custom character devices.
2011-12-14 22:22:19 +00:00
shmfd->shm_kmappings--;
Rename VM_OBJECT_LOCK(), VM_OBJECT_UNLOCK() and VM_OBJECT_TRYLOCK() to their "write" versions. Sponsored by: EMC / Isilon storage division
2013-02-20 12:03:20 +00:00
VM_OBJECT_WUNLOCK(obj);
Add a helper API to allow in-kernel code to map portions of shared memory objects created by shm_open(2) into the kernel's address space. This provides a convenient way for creating shared memory buffers between userland and the kernel without requiring custom character devices.
2011-12-14 22:22:19 +00:00
Use vm_mmap_to_errno(). Submitted by: kib
2011-12-15 15:17:19 +00:00
return (vm_mmap_to_errno(rv));
Add a helper API to allow in-kernel code to map portions of shared memory objects created by shm_open(2) into the kernel's address space. This provides a convenient way for creating shared memory buffers between userland and the kernel without requiring custom character devices.
2011-12-14 22:22:19 +00:00
}
/*
* We require the caller to unmap the entire entry. This allows us to
* safely decrement shm_kmappings when a mapping is removed.
*/
int
shm_unmap(struct file *fp, void *mem, size_t size)
{
struct shmfd *shmfd;
vm_map_entry_t entry;
vm_offset_t kva, ofs;
vm_object_t obj;
vm_pindex_t pindex;
vm_prot_t prot;
boolean_t wired;
vm_map_t map;
int rv;
if (fp->f_type != DTYPE_SHM)
return (EINVAL);
shmfd = fp->f_data;
kva = (vm_offset_t)mem;
ofs = kva & PAGE_MASK;
kva = trunc_page(kva);
size = round_page(size + ofs);
map = kernel_map;
rv = vm_map_lookup(&map, kva, VM_PROT_READ | VM_PROT_WRITE, &entry,
&obj, &pindex, &prot, &wired);
if (rv != KERN_SUCCESS)
return (EINVAL);
if (entry->start != kva || entry->end != kva + size) {
vm_map_lookup_done(map, entry);
return (EINVAL);
}
vm_map_lookup_done(map, entry);
if (obj != shmfd->shm_object)
return (EINVAL);
vm_map_remove(map, kva, kva + size);
Rename VM_OBJECT_LOCK(), VM_OBJECT_UNLOCK() and VM_OBJECT_TRYLOCK() to their "write" versions. Sponsored by: EMC / Isilon storage division
2013-02-20 12:03:20 +00:00
VM_OBJECT_WLOCK(obj);
Add a helper API to allow in-kernel code to map portions of shared memory objects created by shm_open(2) into the kernel's address space. This provides a convenient way for creating shared memory buffers between userland and the kernel without requiring custom character devices.
2011-12-14 22:22:19 +00:00
KASSERT(shmfd->shm_kmappings > 0, ("shm_unmap: object not mapped"));
shmfd->shm_kmappings--;
Rename VM_OBJECT_LOCK(), VM_OBJECT_UNLOCK() and VM_OBJECT_TRYLOCK() to their "write" versions. Sponsored by: EMC / Isilon storage division
2013-02-20 12:03:20 +00:00
VM_OBJECT_WUNLOCK(obj);
Add a helper API to allow in-kernel code to map portions of shared memory objects created by shm_open(2) into the kernel's address space. This provides a convenient way for creating shared memory buffers between userland and the kernel without requiring custom character devices.
2011-12-14 22:22:19 +00:00
return (0);
}
Export some more useful info about shared memory objects to userland via procstat(1) and fstat(1): - Change shm file descriptors to track the pathname they are associated with and add a shm_path() method to copy the path out to a caller-supplied buffer. - Use the fo_stat() method of shared memory objects and shm_path() to export the path, mode, and size of a shared memory object via struct kinfo_file. - Add a struct shmstat to the libprocstat(3) interface along with a procstat_get_shm_info() to export the mode and size of a shared memory object. - Change procstat to always print out the path for a given object if it is valid. - Teach fstat about shared memory objects and to display their path, mode, and size. MFC after: 2 weeks
2012-04-01 18:22:48 +00:00
Add a new fo_fill_kinfo fileops method to add type-specific information to struct kinfo_file. - Move the various fill_*_info() methods out of kern_descrip.c and into the various file type implementations. - Rework the support for kinfo_ofile to generate a suitable kinfo_file object for each file and then convert that to a kinfo_ofile structure rather than keeping a second, different set of code that directly manipulates type-specific file information. - Remove the shm_path() and ksem_info() layering violations. Differential Revision: https://reviews.freebsd.org/D775 Reviewed by: kib, glebius (earlier version)
2014-09-22 16:20:47 +00:00
static int
shm_fill_kinfo(struct file *fp, struct kinfo_file *kif, struct filedesc *fdp)
Export some more useful info about shared memory objects to userland via procstat(1) and fstat(1): - Change shm file descriptors to track the pathname they are associated with and add a shm_path() method to copy the path out to a caller-supplied buffer. - Use the fo_stat() method of shared memory objects and shm_path() to export the path, mode, and size of a shared memory object via struct kinfo_file. - Add a struct shmstat to the libprocstat(3) interface along with a procstat_get_shm_info() to export the mode and size of a shared memory object. - Change procstat to always print out the path for a given object if it is valid. - Teach fstat about shared memory objects and to display their path, mode, and size. MFC after: 2 weeks
2012-04-01 18:22:48 +00:00
{
Add a new fo_fill_kinfo fileops method to add type-specific information to struct kinfo_file. - Move the various fill_*_info() methods out of kern_descrip.c and into the various file type implementations. - Rework the support for kinfo_ofile to generate a suitable kinfo_file object for each file and then convert that to a kinfo_ofile structure rather than keeping a second, different set of code that directly manipulates type-specific file information. - Remove the shm_path() and ksem_info() layering violations. Differential Revision: https://reviews.freebsd.org/D775 Reviewed by: kib, glebius (earlier version)
2014-09-22 16:20:47 +00:00
struct shmfd *shmfd;
kif->kf_type = KF_TYPE_SHM;
shmfd = fp->f_data;
Export some more useful info about shared memory objects to userland via procstat(1) and fstat(1): - Change shm file descriptors to track the pathname they are associated with and add a shm_path() method to copy the path out to a caller-supplied buffer. - Use the fo_stat() method of shared memory objects and shm_path() to export the path, mode, and size of a shared memory object via struct kinfo_file. - Add a struct shmstat to the libprocstat(3) interface along with a procstat_get_shm_info() to export the mode and size of a shared memory object. - Change procstat to always print out the path for a given object if it is valid. - Teach fstat about shared memory objects and to display their path, mode, and size. MFC after: 2 weeks
2012-04-01 18:22:48 +00:00
Add a new fo_fill_kinfo fileops method to add type-specific information to struct kinfo_file. - Move the various fill_*_info() methods out of kern_descrip.c and into the various file type implementations. - Rework the support for kinfo_ofile to generate a suitable kinfo_file object for each file and then convert that to a kinfo_ofile structure rather than keeping a second, different set of code that directly manipulates type-specific file information. - Remove the shm_path() and ksem_info() layering violations. Differential Revision: https://reviews.freebsd.org/D775 Reviewed by: kib, glebius (earlier version)
2014-09-22 16:20:47 +00:00
mtx_lock(&shm_timestamp_lock);
kif->kf_un.kf_file.kf_file_mode = S_IFREG | shmfd->shm_mode; /* XXX */
mtx_unlock(&shm_timestamp_lock);
kif->kf_un.kf_file.kf_file_size = shmfd->shm_size;
if (shmfd->shm_path != NULL) {
sx_slock(&shm_dict_lock);
if (shmfd->shm_path != NULL)
strlcpy(kif->kf_path, shmfd->shm_path,
sizeof(kif->kf_path));
sx_sunlock(&shm_dict_lock);
}
return (0);
Export some more useful info about shared memory objects to userland via procstat(1) and fstat(1): - Change shm file descriptors to track the pathname they are associated with and add a shm_path() method to copy the path out to a caller-supplied buffer. - Use the fo_stat() method of shared memory objects and shm_path() to export the path, mode, and size of a shared memory object via struct kinfo_file. - Add a struct shmstat to the libprocstat(3) interface along with a procstat_get_shm_info() to export the mode and size of a shared memory object. - Change procstat to always print out the path for a given object if it is valid. - Teach fstat about shared memory objects and to display their path, mode, and size. MFC after: 2 weeks
2012-04-01 18:22:48 +00:00
}
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