freebsd-dev/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
/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 2006, 2011, 2016-2017 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.
*
* Portions of this software were developed by BAE Systems, the University of
* Cambridge Computer Laboratory, and Memorial University under DARPA/AFRL
* contract FA8650-15-C-7558 ("CADETS"), as part of the DARPA Transparent
* Computing (TC) research program.
*
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
* 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), shm_rename(2), and shm_unlink(2).
* While most of the implementation is here, vm_mmap.c contains
* mapping logic changes.
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
*
* posixshmcontrol(1) allows users to inspect the state of the memory
* objects. Per-uid swap resource limit controls total amount of
* memory that user can consume for anonymous objects, including
* shared.
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/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_capsicum.h"
#include "opt_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/param.h>
#include <sys/capsicum.h>
#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/filio.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/fnv_hash.h>
#include <sys/kernel.h>
#include <sys/limits.h>
#include <sys/uio.h>
#include <sys/signal.h>
#include <sys/jail.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>
#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 the vm_object mutex to be a rwlock. This will enable in the future further optimizations where the vm_object lock will be held in read mode most of the time the page cache resident pool of pages are accessed for reading purposes. The change is mostly mechanical but few notes are reported: * The KPI changes as follow: - VM_OBJECT_LOCK() -> VM_OBJECT_WLOCK() - VM_OBJECT_TRYLOCK() -> VM_OBJECT_TRYWLOCK() - VM_OBJECT_UNLOCK() -> VM_OBJECT_WUNLOCK() - VM_OBJECT_LOCK_ASSERT(MA_OWNED) -> VM_OBJECT_ASSERT_WLOCKED() (in order to avoid visibility of implementation details) - The read-mode operations are added: VM_OBJECT_RLOCK(), VM_OBJECT_TRYRLOCK(), VM_OBJECT_RUNLOCK(), VM_OBJECT_ASSERT_RLOCKED(), VM_OBJECT_ASSERT_LOCKED() * The vm/vm_pager.h namespace pollution avoidance (forcing requiring sys/mutex.h in consumers directly to cater its inlining functions using VM_OBJECT_LOCK()) imposes that all the vm/vm_pager.h consumers now must include also sys/rwlock.h. * zfs requires a quite convoluted fix to include FreeBSD rwlocks into the compat layer because the name clash between FreeBSD and solaris versions must be avoided. At this purpose zfs redefines the vm_object locking functions directly, isolating the FreeBSD components in specific compat stubs. The KPI results heavilly broken by this commit. Thirdy part ports must be updated accordingly (I can think off-hand of VirtualBox, for example). Sponsored by: EMC / Isilon storage division Reviewed by: jeff Reviewed by: pjd (ZFS specific review) Discussed with: alc Tested by: pho
2013-03-09 02:32:23 +00:00
#include <sys/rwlock.h>
#include <sys/sbuf.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>
#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>
#include <sys/unistd.h>
#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/audit/audit.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>
#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>
#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>
#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;
static struct unrhdr64 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 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_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);
static int shm_dotruncate_locked(struct shmfd *shmfd, off_t length,
void *rl_cookie);
static int shm_copyin_path(struct thread *td, const char *userpath_in,
char **path_out);
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_ioctl_t shm_ioctl;
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_stat_t shm_stat;
static fo_close_t shm_close;
static fo_chmod_t shm_chmod;
static fo_chown_t shm_chown;
static fo_seek_t shm_seek;
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;
static fo_get_seals_t shm_get_seals;
static fo_add_seals_t shm_add_seals;
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. */
struct fileops 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
.fo_read = shm_read,
.fo_write = shm_write,
.fo_truncate = shm_truncate,
.fo_ioctl = shm_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,
.fo_chmod = shm_chmod,
.fo_chown = shm_chown,
.fo_sendfile = vn_sendfile,
.fo_seek = shm_seek,
.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,
.fo_get_seals = shm_get_seals,
.fo_add_seals = shm_add_seals,
.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");
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);
/*
* 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);
return (uiomove(__DECONST(void *, zero_region), tlen, uio));
}
/*
* 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.
*/
rv = vm_page_grab_valid(&m, obj, idx,
VM_ALLOC_NORMAL | VM_ALLOC_WIRED | VM_ALLOC_NOBUSY);
if (rv != VM_PAGER_OK) {
VM_OBJECT_WUNLOCK(obj);
printf("uiomove_object: vm_obj %p idx %jd pager error %d\n",
obj, idx, rv);
return (EIO);
}
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);
vm_pager_page_unswapped(m);
VM_OBJECT_WUNLOCK(obj);
}
vm_page_unwire(m, PQ_ACTIVE);
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);
}
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
td->td_uretoff.tdu_off = offset;
}
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)
{
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
shmfd = fp->f_data;
#ifdef MAC
error = mac_posixshm_check_read(active_cred, fp->f_cred, shmfd);
if (error)
return (error);
#endif
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);
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)
{
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
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);
}
if ((shmfd->shm_seals & F_SEAL_WRITE) != 0)
error = EPERM;
else
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
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
}
int
shm_ioctl(struct file *fp, u_long com, void *data, struct ucred *active_cred,
struct thread *td)
{
switch (com) {
case FIONBIO:
case FIOASYNC:
/*
* Allow fcntl(fd, F_SETFL, O_NONBLOCK) to work,
* just like it would on an unlinked regular file
*/
return (0);
default:
return (ENOTTY);
}
}
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 = howmany(sb->st_size, sb->st_blksize);
mtx_lock(&shm_timestamp_lock);
sb->st_atim = shmfd->shm_atime;
sb->st_ctim = shmfd->shm_ctime;
sb->st_mtim = shmfd->shm_mtime;
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;
mtx_unlock(&shm_timestamp_lock);
sb->st_dev = shm_dev_ino;
sb->st_ino = shmfd->shm_ino;
sb->st_nlink = shmfd->shm_object->ref_count;
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);
}
static int
shm_copyin_path(struct thread *td, const char *userpath_in, char **path_out) {
int error;
char *path;
const char *pr_path;
size_t pr_pathlen;
path = malloc(MAXPATHLEN, M_SHMFD, M_WAITOK);
pr_path = td->td_ucred->cr_prison->pr_path;
/* Construct a full pathname for jailed callers. */
pr_pathlen = strcmp(pr_path, "/") ==
0 ? 0 : strlcpy(path, pr_path, MAXPATHLEN);
error = copyinstr(userpath_in, path + pr_pathlen,
MAXPATHLEN - pr_pathlen, NULL);
if (error != 0)
goto out;
#ifdef KTRACE
if (KTRPOINT(curthread, KTR_NAMEI))
ktrnamei(path);
#endif
/* Require paths to start with a '/' character. */
if (path[pr_pathlen] != '/') {
error = EINVAL;
goto out;
}
*path_out = path;
out:
if (error != 0)
free(path, M_SHMFD);
return (error);
}
static int
shm_dotruncate_locked(struct shmfd *shmfd, off_t length, void *rl_cookie)
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_t object;
vm_page_t m;
vm_pindex_t idx, nobjsize;
vm_ooffset_t delta;
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
KASSERT(length >= 0, ("shm_dotruncate: length < 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
object = shmfd->shm_object;
VM_OBJECT_ASSERT_WLOCKED(object);
rangelock_cookie_assert(rl_cookie, RA_WLOCKED);
if (length == shmfd->shm_size)
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) {
if ((shmfd->shm_seals & F_SEAL_SHRINK) != 0)
return (EPERM);
/*
* Disallow any requests to shrink the size if this
* object is mapped into the kernel.
*/
if (shmfd->shm_kmappings > 0)
return (EBUSY);
/*
* Zero the truncated part of the last page.
*/
base = length & PAGE_MASK;
if (base != 0) {
idx = OFF_TO_IDX(length);
retry:
m = vm_page_grab(object, idx, VM_ALLOC_NOCREAT);
if (m != NULL) {
MPASS(vm_page_all_valid(m));
} else if (vm_pager_has_page(object, idx, NULL, NULL)) {
m = vm_page_alloc(object, idx,
VM_ALLOC_NORMAL | VM_ALLOC_WAITFAIL);
if (m == NULL)
goto retry;
rv = vm_pager_get_pages(object, &m, 1, NULL,
NULL);
if (rv == VM_PAGER_OK) {
/*
* Since the page was not resident,
* and therefore not recently
* accessed, immediately enqueue it
* for asynchronous laundering. The
* current operation is not regarded
* as an access.
*/
vm_page_launder(m);
} else {
vm_page_free(m);
Switch the vm_object mutex to be a rwlock. This will enable in the future further optimizations where the vm_object lock will be held in read mode most of the time the page cache resident pool of pages are accessed for reading purposes. The change is mostly mechanical but few notes are reported: * The KPI changes as follow: - VM_OBJECT_LOCK() -> VM_OBJECT_WLOCK() - VM_OBJECT_TRYLOCK() -> VM_OBJECT_TRYWLOCK() - VM_OBJECT_UNLOCK() -> VM_OBJECT_WUNLOCK() - VM_OBJECT_LOCK_ASSERT(MA_OWNED) -> VM_OBJECT_ASSERT_WLOCKED() (in order to avoid visibility of implementation details) - The read-mode operations are added: VM_OBJECT_RLOCK(), VM_OBJECT_TRYRLOCK(), VM_OBJECT_RUNLOCK(), VM_OBJECT_ASSERT_RLOCKED(), VM_OBJECT_ASSERT_LOCKED() * The vm/vm_pager.h namespace pollution avoidance (forcing requiring sys/mutex.h in consumers directly to cater its inlining functions using VM_OBJECT_LOCK()) imposes that all the vm/vm_pager.h consumers now must include also sys/rwlock.h. * zfs requires a quite convoluted fix to include FreeBSD rwlocks into the compat layer because the name clash between FreeBSD and solaris versions must be avoided. At this purpose zfs redefines the vm_object locking functions directly, isolating the FreeBSD components in specific compat stubs. The KPI results heavilly broken by this commit. Thirdy part ports must be updated accordingly (I can think off-hand of VirtualBox, for example). Sponsored by: EMC / Isilon storage division Reviewed by: jeff Reviewed by: pjd (ZFS specific review) Discussed with: alc Tested by: pho
2013-03-09 02:32:23 +00:00
VM_OBJECT_WUNLOCK(object);
return (EIO);
}
}
if (m != NULL) {
pmap_zero_page_area(m, base, PAGE_SIZE - base);
KASSERT(vm_page_all_valid(m),
("shm_dotruncate: page %p is invalid", m));
vm_page_dirty(m);
vm_page_xunbusy(m);
vm_pager_page_unswapped(m);
}
}
delta = IDX_TO_OFF(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,
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)
swap_pager_freespace(object, nobjsize, delta);
/* Free the swap accounted for shm */
swap_release_by_cred(delta, object->cred);
object->charge -= delta;
} else {
if ((shmfd->shm_seals & F_SEAL_GROW) != 0)
return (EPERM);
/* Try to reserve additional swap space. */
delta = IDX_TO_OFF(nobjsize - object->size);
if (!swap_reserve_by_cred(delta, object->cred))
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;
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
}
int
shm_dotruncate(struct shmfd *shmfd, off_t length)
{
void *rl_cookie;
int error;
rl_cookie = rangelock_wlock(&shmfd->shm_rl, 0, OFF_MAX,
&shmfd->shm_mtx);
VM_OBJECT_WLOCK(shmfd->shm_object);
error = shm_dotruncate_locked(shmfd, length, rl_cookie);
VM_OBJECT_WUNLOCK(shmfd->shm_object);
rangelock_unlock(&shmfd->shm_rl, rl_cookie, &shmfd->shm_mtx);
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
/*
* shmfd object management including creation and reference counting
* routines.
*/
struct shmfd *
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_alloc(struct ucred *ucred, mode_t mode)
{
struct shmfd *shmfd;
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_SWAP, NULL,
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"));
vfs_timestamp(&shmfd->shm_birthtime);
shmfd->shm_atime = shmfd->shm_mtime = shmfd->shm_ctime =
shmfd->shm_birthtime;
shmfd->shm_ino = alloc_unr64(&shm_ino_unr);
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);
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);
}
struct shmfd *
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_hold(struct shmfd *shmfd)
{
refcount_acquire(&shmfd->shm_refs);
return (shmfd);
}
void
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_drop(struct shmfd *shmfd)
{
if (refcount_release(&shmfd->shm_refs)) {
#ifdef MAC
mac_posixshm_destroy(shmfd);
#endif
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);
free(shmfd, M_SHMFD);
}
}
/*
* Determine if the credentials have sufficient permissions for a
* specified combination of FREAD and FWRITE.
*/
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_access(struct shmfd *shmfd, struct ucred *ucred, int flags)
{
accmode_t accmode;
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
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)
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)
accmode |= VWRITE;
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
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);
new_unrhdr64(&shm_ino_unr, 1);
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
}
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);
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);
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
kern_shm_open(struct thread *td, const char *userpath, int flags, mode_t mode,
struct filecaps *fcaps, int initial_seals)
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;
void *rl_cookie;
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
Fnv32_t fnv;
mode_t cmode;
int fd, error;
#ifdef CAPABILITY_MODE
/*
* shm_open(2) is only allowed for anonymous objects.
*/
if (IN_CAPABILITY_MODE(td) && (userpath != SHM_ANON))
return (ECAPMODE);
#endif
AUDIT_ARG_FFLAGS(flags);
AUDIT_ARG_MODE(mode);
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);
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);
/*
* Currently only F_SEAL_SEAL may be set when creating or opening shmfd.
* If the decision is made later to allow additional seals, care must be
* taken below to ensure that the seals are properly set if the shmfd
* already existed -- this currently assumes that only F_SEAL_SEAL can
* be set and doesn't take further precautions to ensure the validity of
* the seals being added with respect to current mappings.
*/
if ((initial_seals & ~F_SEAL_SEAL) != 0)
return (EINVAL);
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
fdp = td->td_proc->p_fd;
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
/*
* shm_open(2) created shm should always have O_CLOEXEC set, as mandated
* by POSIX. We allow it to be unset here so that an in-kernel
* interface may be written as a thin layer around shm, optionally not
* setting CLOEXEC. For shm_open(2), O_CLOEXEC is set unconditionally
* in sys_shm_open() to keep this implementation compliant.
*/
error = falloc_caps(td, &fp, &fd, flags & 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. */
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. */
if ((flags & O_ACCMODE) == O_RDONLY) {
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);
shmfd->shm_seals = initial_seals;
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 {
error = shm_copyin_path(td, userpath, &path);
if (error != 0) {
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);
}
AUDIT_ARG_UPATH1_CANON(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
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. */
if (flags & O_CREAT) {
#ifdef MAC
error = mac_posixshm_check_create(td->td_ucred,
path);
if (error == 0) {
#endif
shmfd = shm_alloc(td->td_ucred, cmode);
shmfd->shm_seals = initial_seals;
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 {
rl_cookie = rangelock_wlock(&shmfd->shm_rl, 0, OFF_MAX,
&shmfd->shm_mtx);
/*
* kern_shm_open() likely shouldn't ever error out on
* trying to set a seal that already exists, unlike
* F_ADD_SEALS. This would break terribly as
* shm_open(2) actually sets F_SEAL_SEAL to maintain
* historical behavior where the underlying file could
* not be sealed.
*/
initial_seals &= ~shmfd->shm_seals;
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 already exists, obtain a new
* reference if requested and permitted.
*/
free(path, M_SHMFD);
/*
* initial_seals can't set additional seals if we've
* already been set F_SEAL_SEAL. If F_SEAL_SEAL is set,
* then we've already removed that one from
* initial_seals. This is currently redundant as we
* only allow setting F_SEAL_SEAL at creation time, but
* it's cheap to check and decreases the effort required
* to allow additional seals.
*/
if ((shmfd->shm_seals & F_SEAL_SEAL) != 0 &&
initial_seals != 0)
error = EPERM;
else 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,
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,
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 &&
(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)) {
VM_OBJECT_WLOCK(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
#ifdef MAC
error = mac_posixshm_check_truncate(
td->td_ucred, fp->f_cred, shmfd);
if (error == 0)
#endif
error = shm_dotruncate_locked(shmfd, 0,
rl_cookie);
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
}
if (error == 0) {
/*
* Currently we only allow F_SEAL_SEAL to be
* set initially. As noted above, this would
* need to be reworked should that change.
*/
shmfd->shm_seals |= initial_seals;
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_hold(shmfd);
}
rangelock_unlock(&shmfd->shm_rl, rl_cookie,
&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
}
sx_xunlock(&shm_dict_lock);
if (error) {
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);
}
}
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);
}
/* System calls. */
#ifdef COMPAT_FREEBSD12
int
freebsd12_shm_open(struct thread *td, struct freebsd12_shm_open_args *uap)
{
return (kern_shm_open(td, uap->path, uap->flags | O_CLOEXEC, uap->mode,
NULL, F_SEAL_SEAL));
}
#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
int
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;
error = shm_copyin_path(td, uap->path, &path);
if (error != 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 (error);
AUDIT_ARG_UPATH1_CANON(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
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
sys_shm_rename(struct thread *td, struct shm_rename_args *uap)
{
char *path_from = NULL, *path_to = NULL;
Fnv32_t fnv_from, fnv_to;
struct shmfd *fd_from;
struct shmfd *fd_to;
int error;
int flags;
flags = uap->flags;
AUDIT_ARG_FFLAGS(flags);
/*
* Make sure the user passed only valid flags.
* If you add a new flag, please add a new term here.
*/
if ((flags & ~(
SHM_RENAME_NOREPLACE |
SHM_RENAME_EXCHANGE
)) != 0) {
error = EINVAL;
goto out;
}
/*
* EXCHANGE and NOREPLACE don't quite make sense together. Let's
* force the user to choose one or the other.
*/
if ((flags & SHM_RENAME_NOREPLACE) != 0 &&
(flags & SHM_RENAME_EXCHANGE) != 0) {
error = EINVAL;
goto out;
}
/* Renaming to or from anonymous makes no sense */
if (uap->path_from == SHM_ANON || uap->path_to == SHM_ANON) {
error = EINVAL;
goto out;
}
error = shm_copyin_path(td, uap->path_from, &path_from);
if (error != 0)
goto out;
error = shm_copyin_path(td, uap->path_to, &path_to);
if (error != 0)
goto out;
AUDIT_ARG_UPATH1_CANON(path_from);
AUDIT_ARG_UPATH2_CANON(path_to);
/* Rename with from/to equal is a no-op */
if (strcmp(path_from, path_to) == 0)
goto out;
fnv_from = fnv_32_str(path_from, FNV1_32_INIT);
fnv_to = fnv_32_str(path_to, FNV1_32_INIT);
sx_xlock(&shm_dict_lock);
fd_from = shm_lookup(path_from, fnv_from);
if (fd_from == NULL) {
error = ENOENT;
goto out_locked;
}
fd_to = shm_lookup(path_to, fnv_to);
if ((flags & SHM_RENAME_NOREPLACE) != 0 && fd_to != NULL) {
error = EEXIST;
goto out_locked;
}
/*
* Unconditionally prevents shm_remove from invalidating the 'from'
* shm's state.
*/
shm_hold(fd_from);
error = shm_remove(path_from, fnv_from, td->td_ucred);
/*
* One of my assumptions failed if ENOENT (e.g. locking didn't
* protect us)
*/
KASSERT(error != ENOENT, ("Our shm disappeared during shm_rename: %s",
path_from));
if (error != 0) {
shm_drop(fd_from);
goto out_locked;
}
/*
* If we are exchanging, we need to ensure the shm_remove below
* doesn't invalidate the dest shm's state.
*/
if ((flags & SHM_RENAME_EXCHANGE) != 0 && fd_to != NULL)
shm_hold(fd_to);
/*
* NOTE: if path_to is not already in the hash, c'est la vie;
* it simply means we have nothing already at path_to to unlink.
* That is the ENOENT case.
*
* If we somehow don't have access to unlink this guy, but
* did for the shm at path_from, then relink the shm to path_from
* and abort with EACCES.
*
* All other errors: that is weird; let's relink and abort the
* operation.
*/
error = shm_remove(path_to, fnv_to, td->td_ucred);
if (error != 0 && error != ENOENT) {
shm_insert(path_from, fnv_from, fd_from);
shm_drop(fd_from);
/* Don't free path_from now, since the hash references it */
path_from = NULL;
goto out_locked;
}
error = 0;
shm_insert(path_to, fnv_to, fd_from);
/* Don't free path_to now, since the hash references it */
path_to = NULL;
/* We kept a ref when we removed, and incremented again in insert */
shm_drop(fd_from);
KASSERT(fd_from->shm_refs > 0, ("Expected >0 refs; got: %d\n",
fd_from->shm_refs));
if ((flags & SHM_RENAME_EXCHANGE) != 0 && fd_to != NULL) {
shm_insert(path_from, fnv_from, fd_to);
path_from = NULL;
shm_drop(fd_to);
KASSERT(fd_to->shm_refs > 0, ("Expected >0 refs; got: %d\n",
fd_to->shm_refs));
}
out_locked:
sx_xunlock(&shm_dict_lock);
out:
free(path_from, M_SHMFD);
free(path_to, M_SHMFD);
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
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;
bool writecnt;
void *rl_cookie;
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
shmfd = fp->f_data;
maxprot = VM_PROT_NONE;
rl_cookie = rangelock_rlock(&shmfd->shm_rl, 0, objsize,
&shmfd->shm_mtx);
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
/* 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;
writecnt = (flags & MAP_SHARED) != 0 && (prot & VM_PROT_WRITE) != 0;
if (writecnt && (shmfd->shm_seals & F_SEAL_WRITE) != 0) {
error = EPERM;
goto out;
}
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
/* Don't permit shared writable mappings on read-only descriptors. */
if (writecnt && (maxprot & VM_PROT_WRITE) == 0) {
error = EACCES;
goto out;
}
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
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
/* See comment in vn_mmap(). */
if (
#ifdef _LP64
objsize > OFF_MAX ||
#endif
foff < 0 || foff > OFF_MAX - objsize) {
error = EINVAL;
goto out;
}
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)
goto out;
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
#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
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
if (writecnt)
vm_pager_update_writecount(shmfd->shm_object, 0, objsize);
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, writecnt, td);
if (error != 0) {
if (writecnt)
vm_pager_release_writecount(shmfd->shm_object, 0,
objsize);
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
vm_object_deallocate(shmfd->shm_object);
}
out:
rangelock_unlock(&shmfd->shm_rl, rl_cookie, &shmfd->shm_mtx);
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_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;
error = 0;
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)))
goto out;
shmfd->shm_uid = uid;
shmfd->shm_gid = gid;
out:
mtx_unlock(&shm_timestamp_lock);
return (error);
}
/*
* 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;
Switch the vm_object mutex to be a rwlock. This will enable in the future further optimizations where the vm_object lock will be held in read mode most of the time the page cache resident pool of pages are accessed for reading purposes. The change is mostly mechanical but few notes are reported: * The KPI changes as follow: - VM_OBJECT_LOCK() -> VM_OBJECT_WLOCK() - VM_OBJECT_TRYLOCK() -> VM_OBJECT_TRYWLOCK() - VM_OBJECT_UNLOCK() -> VM_OBJECT_WUNLOCK() - VM_OBJECT_LOCK_ASSERT(MA_OWNED) -> VM_OBJECT_ASSERT_WLOCKED() (in order to avoid visibility of implementation details) - The read-mode operations are added: VM_OBJECT_RLOCK(), VM_OBJECT_TRYRLOCK(), VM_OBJECT_RUNLOCK(), VM_OBJECT_ASSERT_RLOCKED(), VM_OBJECT_ASSERT_LOCKED() * The vm/vm_pager.h namespace pollution avoidance (forcing requiring sys/mutex.h in consumers directly to cater its inlining functions using VM_OBJECT_LOCK()) imposes that all the vm/vm_pager.h consumers now must include also sys/rwlock.h. * zfs requires a quite convoluted fix to include FreeBSD rwlocks into the compat layer because the name clash between FreeBSD and solaris versions must be avoided. At this purpose zfs redefines the vm_object locking functions directly, isolating the FreeBSD components in specific compat stubs. The KPI results heavilly broken by this commit. Thirdy part ports must be updated accordingly (I can think off-hand of VirtualBox, for example). Sponsored by: EMC / Isilon storage division Reviewed by: jeff Reviewed by: pjd (ZFS specific review) Discussed with: alc Tested by: pho
2013-03-09 02:32:23 +00:00
VM_OBJECT_WLOCK(obj);
/*
* 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)) {
Switch the vm_object mutex to be a rwlock. This will enable in the future further optimizations where the vm_object lock will be held in read mode most of the time the page cache resident pool of pages are accessed for reading purposes. The change is mostly mechanical but few notes are reported: * The KPI changes as follow: - VM_OBJECT_LOCK() -> VM_OBJECT_WLOCK() - VM_OBJECT_TRYLOCK() -> VM_OBJECT_TRYWLOCK() - VM_OBJECT_UNLOCK() -> VM_OBJECT_WUNLOCK() - VM_OBJECT_LOCK_ASSERT(MA_OWNED) -> VM_OBJECT_ASSERT_WLOCKED() (in order to avoid visibility of implementation details) - The read-mode operations are added: VM_OBJECT_RLOCK(), VM_OBJECT_TRYRLOCK(), VM_OBJECT_RUNLOCK(), VM_OBJECT_ASSERT_RLOCKED(), VM_OBJECT_ASSERT_LOCKED() * The vm/vm_pager.h namespace pollution avoidance (forcing requiring sys/mutex.h in consumers directly to cater its inlining functions using VM_OBJECT_LOCK()) imposes that all the vm/vm_pager.h consumers now must include also sys/rwlock.h. * zfs requires a quite convoluted fix to include FreeBSD rwlocks into the compat layer because the name clash between FreeBSD and solaris versions must be avoided. At this purpose zfs redefines the vm_object locking functions directly, isolating the FreeBSD components in specific compat stubs. The KPI results heavilly broken by this commit. Thirdy part ports must be updated accordingly (I can think off-hand of VirtualBox, for example). Sponsored by: EMC / Isilon storage division Reviewed by: jeff Reviewed by: pjd (ZFS specific review) Discussed with: alc Tested by: pho
2013-03-09 02:32:23 +00:00
VM_OBJECT_WUNLOCK(obj);
return (EINVAL);
}
shmfd->shm_kmappings++;
vm_object_reference_locked(obj);
Switch the vm_object mutex to be a rwlock. This will enable in the future further optimizations where the vm_object lock will be held in read mode most of the time the page cache resident pool of pages are accessed for reading purposes. The change is mostly mechanical but few notes are reported: * The KPI changes as follow: - VM_OBJECT_LOCK() -> VM_OBJECT_WLOCK() - VM_OBJECT_TRYLOCK() -> VM_OBJECT_TRYWLOCK() - VM_OBJECT_UNLOCK() -> VM_OBJECT_WUNLOCK() - VM_OBJECT_LOCK_ASSERT(MA_OWNED) -> VM_OBJECT_ASSERT_WLOCKED() (in order to avoid visibility of implementation details) - The read-mode operations are added: VM_OBJECT_RLOCK(), VM_OBJECT_TRYRLOCK(), VM_OBJECT_RUNLOCK(), VM_OBJECT_ASSERT_RLOCKED(), VM_OBJECT_ASSERT_LOCKED() * The vm/vm_pager.h namespace pollution avoidance (forcing requiring sys/mutex.h in consumers directly to cater its inlining functions using VM_OBJECT_LOCK()) imposes that all the vm/vm_pager.h consumers now must include also sys/rwlock.h. * zfs requires a quite convoluted fix to include FreeBSD rwlocks into the compat layer because the name clash between FreeBSD and solaris versions must be avoided. At this purpose zfs redefines the vm_object locking functions directly, isolating the FreeBSD components in specific compat stubs. The KPI results heavilly broken by this commit. Thirdy part ports must be updated accordingly (I can think off-hand of VirtualBox, for example). Sponsored by: EMC / Isilon storage division Reviewed by: jeff Reviewed by: pjd (ZFS specific review) Discussed with: alc Tested by: pho
2013-03-09 02:32:23 +00:00
VM_OBJECT_WUNLOCK(obj);
/* 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);
rv = vm_map_find(kernel_map, obj, offset, &kva, size, 0,
VMFS_OPTIMAL_SPACE, VM_PROT_READ | VM_PROT_WRITE,
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. */
Switch the vm_object mutex to be a rwlock. This will enable in the future further optimizations where the vm_object lock will be held in read mode most of the time the page cache resident pool of pages are accessed for reading purposes. The change is mostly mechanical but few notes are reported: * The KPI changes as follow: - VM_OBJECT_LOCK() -> VM_OBJECT_WLOCK() - VM_OBJECT_TRYLOCK() -> VM_OBJECT_TRYWLOCK() - VM_OBJECT_UNLOCK() -> VM_OBJECT_WUNLOCK() - VM_OBJECT_LOCK_ASSERT(MA_OWNED) -> VM_OBJECT_ASSERT_WLOCKED() (in order to avoid visibility of implementation details) - The read-mode operations are added: VM_OBJECT_RLOCK(), VM_OBJECT_TRYRLOCK(), VM_OBJECT_RUNLOCK(), VM_OBJECT_ASSERT_RLOCKED(), VM_OBJECT_ASSERT_LOCKED() * The vm/vm_pager.h namespace pollution avoidance (forcing requiring sys/mutex.h in consumers directly to cater its inlining functions using VM_OBJECT_LOCK()) imposes that all the vm/vm_pager.h consumers now must include also sys/rwlock.h. * zfs requires a quite convoluted fix to include FreeBSD rwlocks into the compat layer because the name clash between FreeBSD and solaris versions must be avoided. At this purpose zfs redefines the vm_object locking functions directly, isolating the FreeBSD components in specific compat stubs. The KPI results heavilly broken by this commit. Thirdy part ports must be updated accordingly (I can think off-hand of VirtualBox, for example). Sponsored by: EMC / Isilon storage division Reviewed by: jeff Reviewed by: pjd (ZFS specific review) Discussed with: alc Tested by: pho
2013-03-09 02:32:23 +00:00
VM_OBJECT_WLOCK(obj);
shmfd->shm_kmappings--;
Switch the vm_object mutex to be a rwlock. This will enable in the future further optimizations where the vm_object lock will be held in read mode most of the time the page cache resident pool of pages are accessed for reading purposes. The change is mostly mechanical but few notes are reported: * The KPI changes as follow: - VM_OBJECT_LOCK() -> VM_OBJECT_WLOCK() - VM_OBJECT_TRYLOCK() -> VM_OBJECT_TRYWLOCK() - VM_OBJECT_UNLOCK() -> VM_OBJECT_WUNLOCK() - VM_OBJECT_LOCK_ASSERT(MA_OWNED) -> VM_OBJECT_ASSERT_WLOCKED() (in order to avoid visibility of implementation details) - The read-mode operations are added: VM_OBJECT_RLOCK(), VM_OBJECT_TRYRLOCK(), VM_OBJECT_RUNLOCK(), VM_OBJECT_ASSERT_RLOCKED(), VM_OBJECT_ASSERT_LOCKED() * The vm/vm_pager.h namespace pollution avoidance (forcing requiring sys/mutex.h in consumers directly to cater its inlining functions using VM_OBJECT_LOCK()) imposes that all the vm/vm_pager.h consumers now must include also sys/rwlock.h. * zfs requires a quite convoluted fix to include FreeBSD rwlocks into the compat layer because the name clash between FreeBSD and solaris versions must be avoided. At this purpose zfs redefines the vm_object locking functions directly, isolating the FreeBSD components in specific compat stubs. The KPI results heavilly broken by this commit. Thirdy part ports must be updated accordingly (I can think off-hand of VirtualBox, for example). Sponsored by: EMC / Isilon storage division Reviewed by: jeff Reviewed by: pjd (ZFS specific review) Discussed with: alc Tested by: pho
2013-03-09 02:32:23 +00:00
VM_OBJECT_WUNLOCK(obj);
return (vm_mmap_to_errno(rv));
}
/*
* 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);
Switch the vm_object mutex to be a rwlock. This will enable in the future further optimizations where the vm_object lock will be held in read mode most of the time the page cache resident pool of pages are accessed for reading purposes. The change is mostly mechanical but few notes are reported: * The KPI changes as follow: - VM_OBJECT_LOCK() -> VM_OBJECT_WLOCK() - VM_OBJECT_TRYLOCK() -> VM_OBJECT_TRYWLOCK() - VM_OBJECT_UNLOCK() -> VM_OBJECT_WUNLOCK() - VM_OBJECT_LOCK_ASSERT(MA_OWNED) -> VM_OBJECT_ASSERT_WLOCKED() (in order to avoid visibility of implementation details) - The read-mode operations are added: VM_OBJECT_RLOCK(), VM_OBJECT_TRYRLOCK(), VM_OBJECT_RUNLOCK(), VM_OBJECT_ASSERT_RLOCKED(), VM_OBJECT_ASSERT_LOCKED() * The vm/vm_pager.h namespace pollution avoidance (forcing requiring sys/mutex.h in consumers directly to cater its inlining functions using VM_OBJECT_LOCK()) imposes that all the vm/vm_pager.h consumers now must include also sys/rwlock.h. * zfs requires a quite convoluted fix to include FreeBSD rwlocks into the compat layer because the name clash between FreeBSD and solaris versions must be avoided. At this purpose zfs redefines the vm_object locking functions directly, isolating the FreeBSD components in specific compat stubs. The KPI results heavilly broken by this commit. Thirdy part ports must be updated accordingly (I can think off-hand of VirtualBox, for example). Sponsored by: EMC / Isilon storage division Reviewed by: jeff Reviewed by: pjd (ZFS specific review) Discussed with: alc Tested by: pho
2013-03-09 02:32:23 +00:00
VM_OBJECT_WLOCK(obj);
KASSERT(shmfd->shm_kmappings > 0, ("shm_unmap: object not mapped"));
shmfd->shm_kmappings--;
Switch the vm_object mutex to be a rwlock. This will enable in the future further optimizations where the vm_object lock will be held in read mode most of the time the page cache resident pool of pages are accessed for reading purposes. The change is mostly mechanical but few notes are reported: * The KPI changes as follow: - VM_OBJECT_LOCK() -> VM_OBJECT_WLOCK() - VM_OBJECT_TRYLOCK() -> VM_OBJECT_TRYWLOCK() - VM_OBJECT_UNLOCK() -> VM_OBJECT_WUNLOCK() - VM_OBJECT_LOCK_ASSERT(MA_OWNED) -> VM_OBJECT_ASSERT_WLOCKED() (in order to avoid visibility of implementation details) - The read-mode operations are added: VM_OBJECT_RLOCK(), VM_OBJECT_TRYRLOCK(), VM_OBJECT_RUNLOCK(), VM_OBJECT_ASSERT_RLOCKED(), VM_OBJECT_ASSERT_LOCKED() * The vm/vm_pager.h namespace pollution avoidance (forcing requiring sys/mutex.h in consumers directly to cater its inlining functions using VM_OBJECT_LOCK()) imposes that all the vm/vm_pager.h consumers now must include also sys/rwlock.h. * zfs requires a quite convoluted fix to include FreeBSD rwlocks into the compat layer because the name clash between FreeBSD and solaris versions must be avoided. At this purpose zfs redefines the vm_object locking functions directly, isolating the FreeBSD components in specific compat stubs. The KPI results heavilly broken by this commit. Thirdy part ports must be updated accordingly (I can think off-hand of VirtualBox, for example). Sponsored by: EMC / Isilon storage division Reviewed by: jeff Reviewed by: pjd (ZFS specific review) Discussed with: alc Tested by: pho
2013-03-09 02:32:23 +00:00
VM_OBJECT_WUNLOCK(obj);
return (0);
}
static int
shm_fill_kinfo_locked(struct shmfd *shmfd, struct kinfo_file *kif, bool list)
{
const char *path, *pr_path;
size_t pr_pathlen;
bool visible;
sx_assert(&shm_dict_lock, SA_LOCKED);
kif->kf_type = KF_TYPE_SHM;
kif->kf_un.kf_file.kf_file_mode = S_IFREG | shmfd->shm_mode;
kif->kf_un.kf_file.kf_file_size = shmfd->shm_size;
if (shmfd->shm_path != NULL) {
2016-04-14 17:07:26 +00:00
if (shmfd->shm_path != NULL) {
path = shmfd->shm_path;
pr_path = curthread->td_ucred->cr_prison->pr_path;
2016-04-14 17:07:26 +00:00
if (strcmp(pr_path, "/") != 0) {
/* Return the jail-rooted pathname. */
pr_pathlen = strlen(pr_path);
visible = strncmp(path, pr_path, pr_pathlen)
== 0 && path[pr_pathlen] == '/';
if (list && !visible)
return (EPERM);
if (visible)
path += pr_pathlen;
}
strlcpy(kif->kf_path, path, sizeof(kif->kf_path));
}
}
return (0);
}
static int
shm_fill_kinfo(struct file *fp, struct kinfo_file *kif,
struct filedesc *fdp __unused)
{
int res;
sx_slock(&shm_dict_lock);
res = shm_fill_kinfo_locked(fp->f_data, kif, false);
sx_sunlock(&shm_dict_lock);
return (res);
}
static int
shm_add_seals(struct file *fp, int seals)
{
struct shmfd *shmfd;
void *rl_cookie;
vm_ooffset_t writemappings;
int error, nseals;
error = 0;
shmfd = fp->f_data;
rl_cookie = rangelock_wlock(&shmfd->shm_rl, 0, OFF_MAX,
&shmfd->shm_mtx);
/* Even already-set seals should result in EPERM. */
if ((shmfd->shm_seals & F_SEAL_SEAL) != 0) {
error = EPERM;
goto out;
}
nseals = seals & ~shmfd->shm_seals;
if ((nseals & F_SEAL_WRITE) != 0) {
/*
* The rangelock above prevents writable mappings from being
* added after we've started applying seals. The RLOCK here
* is to avoid torn reads on ILP32 arches as unmapping/reducing
* writemappings will be done without a rangelock.
*/
VM_OBJECT_RLOCK(shmfd->shm_object);
writemappings = shmfd->shm_object->un_pager.swp.writemappings;
VM_OBJECT_RUNLOCK(shmfd->shm_object);
/* kmappings are also writable */
if (writemappings > 0) {
error = EBUSY;
goto out;
}
}
shmfd->shm_seals |= nseals;
out:
rangelock_unlock(&shmfd->shm_rl, rl_cookie, &shmfd->shm_mtx);
return (error);
}
static int
shm_get_seals(struct file *fp, int *seals)
{
struct shmfd *shmfd;
shmfd = fp->f_data;
*seals = shmfd->shm_seals;
return (0);
}
static int
sysctl_posix_shm_list(SYSCTL_HANDLER_ARGS)
{
struct shm_mapping *shmm;
struct sbuf sb;
struct kinfo_file kif;
u_long i;
ssize_t curlen;
int error, error2;
sbuf_new_for_sysctl(&sb, NULL, sizeof(struct kinfo_file) * 5, req);
sbuf_clear_flags(&sb, SBUF_INCLUDENUL);
curlen = 0;
error = 0;
sx_slock(&shm_dict_lock);
for (i = 0; i < shm_hash + 1; i++) {
LIST_FOREACH(shmm, &shm_dictionary[i], sm_link) {
error = shm_fill_kinfo_locked(shmm->sm_shmfd,
&kif, true);
if (error == EPERM)
continue;
if (error != 0)
break;
pack_kinfo(&kif);
if (req->oldptr != NULL &&
kif.kf_structsize + curlen > req->oldlen)
break;
error = sbuf_bcat(&sb, &kif, kif.kf_structsize) == 0 ?
0 : ENOMEM;
if (error != 0)
break;
curlen += kif.kf_structsize;
}
}
sx_sunlock(&shm_dict_lock);
error2 = sbuf_finish(&sb);
sbuf_delete(&sb);
return (error != 0 ? error : error2);
}
SYSCTL_PROC(_kern_ipc, OID_AUTO, posix_shm_list,
CTLFLAG_RD | CTLFLAG_MPSAFE | CTLTYPE_OPAQUE,
NULL, 0, sysctl_posix_shm_list, "",
"POSIX SHM list");
int
kern_shm_open2(struct thread *td, const char *path, int flags, mode_t mode,
int shmflags, const char *name __unused)
{
int initial_seals;
if ((shmflags & ~SHM_ALLOW_SEALING) != 0)
return (EINVAL);
initial_seals = F_SEAL_SEAL;
if ((shmflags & SHM_ALLOW_SEALING) != 0)
initial_seals &= ~F_SEAL_SEAL;
return (kern_shm_open(td, path, flags, mode, NULL, initial_seals));
}
/*
* This version of the shm_open() interface leaves CLOEXEC behavior up to the
* caller, and libc will enforce it for the traditional shm_open() call. This
* allows other consumers, like memfd_create(), to opt-in for CLOEXEC. This
* interface also includes a 'name' argument that is currently unused, but could
* potentially be exported later via some interface for debugging purposes.
* From the kernel's perspective, it is optional. Individual consumers like
* memfd_create() may require it in order to be compatible with other systems
* implementing the same function.
*/
int
sys_shm_open2(struct thread *td, struct shm_open2_args *uap)
{
return (kern_shm_open2(td, uap->path, uap->flags, uap->mode,
uap->shmflags, uap->name));
}