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freebsd-nq/sys/fs/fifofs/fifo_vnops.c

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/* -> /*- for copyright notices, minor format tweaks as necessary
2005-01-06 18:10:42 +00:00
/*-
sys: further adoption of SPDX licensing ID tags. Mainly focus on files that use BSD 3-Clause license. The Software Package Data Exchange (SPDX) group provides a specification to make it easier for automated tools to detect and summarize well known opensource licenses. We are gradually adopting the specification, noting that the tags are considered only advisory and do not, in any way, superceed or replace the license texts. Special thanks to Wind River for providing access to "The Duke of Highlander" tool: an older (2014) run over FreeBSD tree was useful as a starting point.
2017-11-20 19:43:44 +00:00
* SPDX-License-Identifier: BSD-3-Clause
*
This is the kernel Lite/2 commit. There are some requisite userland changes, so don't expect to be able to run the kernel as-is (very well) without the appropriate Lite/2 userland changes. The system boots and can mount UFS filesystems. Untested: ext2fs, msdosfs, NFS Known problems: Incorrect Berkeley ID strings in some files. Mount_std mounts will not work until the getfsent library routine is changed. Reviewed by: various people Submitted by: Jeffery Hsu <hsu@freebsd.org>
1997-02-10 02:22:35 +00:00
* Copyright (c) 1990, 1993, 1995
Trim down now (believed to be) unused fifo_ioctl() and fifo_kqfilter() VOP implementations, since they in theory are used only on open file descriptors, in which case the ioctls are via fifo_ioctl_f() and kqueue requests are via fifo_kqfilter_f(). Generate warnings if they are entered for now. These printf() calls should become panic() calls. Annotate and re-implement fifo_ioctl_f(): don't arbitrarily forward ioctls to the socket layer, only forward the ones we explicitly support for fifos. In the case of FIONREAD, don't forward the request to the write socket on a read-write fifo, or the read result is overwritten. Annotate a nasty case for the undefined POSIX O_RDWR on fifos, in which failure of the second ioctl will result in the socket pair being in an inconsistent state. Assert copyright as I find myself rewriting non-trivial parts of fifofs. MFC after: 3 days
2005-09-13 17:46:48 +00:00
* The Regents of the University of California.
* Copyright (c) 2005 Robert N. M. Watson
merge pipe and fifo implementations Also reviewed by: jhb, jilles (initial revision) Tested by: pho, jilles Submitted by: gianni Reviewed by: bde
2012-02-23 18:37:30 +00:00
* Copyright (c) 2012 Giovanni Trematerra
Trim down now (believed to be) unused fifo_ioctl() and fifo_kqfilter() VOP implementations, since they in theory are used only on open file descriptors, in which case the ioctls are via fifo_ioctl_f() and kqueue requests are via fifo_kqfilter_f(). Generate warnings if they are entered for now. These printf() calls should become panic() calls. Annotate and re-implement fifo_ioctl_f(): don't arbitrarily forward ioctls to the socket layer, only forward the ones we explicitly support for fifos. In the case of FIONREAD, don't forward the request to the write socket on a read-write fifo, or the read result is overwritten. Annotate a nasty case for the undefined POSIX O_RDWR on fifos, in which failure of the second ioctl will result in the socket pair being in an inconsistent state. Assert copyright as I find myself rewriting non-trivial parts of fifofs. MFC after: 3 days
2005-09-13 17:46:48 +00:00
* All rights reserved.
BSD 4.4 Lite Kernel Sources
1994-05-24 10:09:53 +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.
Renumber copyright clause 4 Renumber cluase 4 to 3, per what everybody else did when BSD granted them permission to remove clause 3. My insistance on keeping the same numbering for legal reasons is too pedantic, so give up on that point. Submitted by: Jan Schaumann <jschauma@stevens.edu> Pull Request: https://github.com/freebsd/freebsd/pull/96
2017-02-28 23:42:47 +00:00
* 3. Neither the name of the University nor the names of its contributors
BSD 4.4 Lite Kernel Sources
1994-05-24 10:09:53 +00:00
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
*
This is the kernel Lite/2 commit. There are some requisite userland changes, so don't expect to be able to run the kernel as-is (very well) without the appropriate Lite/2 userland changes. The system boots and can mount UFS filesystems. Untested: ext2fs, msdosfs, NFS Known problems: Incorrect Berkeley ID strings in some files. Mount_std mounts will not work until the getfsent library routine is changed. Reviewed by: various people Submitted by: Jeffery Hsu <hsu@freebsd.org>
1997-02-10 02:22:35 +00:00
* @(#)fifo_vnops.c 8.10 (Berkeley) 5/27/95
$Id$ -> $FreeBSD$
1999-08-28 01:08:13 +00:00
* $FreeBSD$
BSD 4.4 Lite Kernel Sources
1994-05-24 10:09:53 +00:00
*/
#include <sys/param.h>
Revert the change of #includes in sys/filedesc.h and sys/socketvar.h. Requested by: bde Since locking sigio_lock is usually followed by calling pgsigio(), move the declaration of sigio_lock and the definitions of SIGIO_*() to sys/signalvar.h. While I am here, sort include files alphabetically, where possible.
2002-04-30 01:54:54 +00:00
#include <sys/event.h>
Add file ops to fifofs so that we can bypass vnodes (and Giant) for the heavy-duty operations (read, write, poll/select, kqueue). Disabled for now, enable with "vfs.fifofs.fops=1" in loader.conf.
2004-11-15 14:51:44 +00:00
#include <sys/file.h>
#include <sys/filedesc.h>
Revert the change of #includes in sys/filedesc.h and sys/socketvar.h. Requested by: bde Since locking sigio_lock is usually followed by calling pgsigio(), move the declaration of sigio_lock and the definitions of SIGIO_*() to sys/signalvar.h. While I am here, sort include files alphabetically, where possible.
2002-04-30 01:54:54 +00:00
#include <sys/filio.h>
#include <sys/fcntl.h>
Rstored #include of <sys/kernel.h> so that this compiles without warnings again. Submitted by: bde
1997-02-12 16:26:37 +00:00
#include <sys/kernel.h>
Don't include <sys/lock.h> in headers when only `struct simplelock' is required. Fixed everything that depended on the pollution.
1997-12-05 19:55:52 +00:00
#include <sys/lock.h>
Include sys/_lock.h and sys/_mutex.h to reduce namespace pollution. Requested by: jhb
2002-01-13 21:37:49 +00:00
#include <sys/mutex.h>
Last major round (Unless Bruce thinks of somthing :-) of malloc changes. Distribute all but the most fundamental malloc types. This time I also remembered the trick to making things static: Put "static" in front of them. A couple of finer points by: bde
1997-10-12 20:26:33 +00:00
#include <sys/malloc.h>
merge pipe and fifo implementations Also reviewed by: jhb, jilles (initial revision) Tested by: pho, jilles Submitted by: gianni Reviewed by: bde
2012-02-23 18:37:30 +00:00
#include <sys/selinfo.h>
#include <sys/pipe.h>
Remove kernel support for M:N threading. While the KSE project was quite successful in bringing threading to FreeBSD, the M:N approach taken by the kse library was never developed to its full potential. Backwards compatibility will be provided via libmap.conf for dynamically linked binaries and static binaries will be broken.
2008-03-12 10:12:01 +00:00
#include <sys/proc.h>
Revert the change of #includes in sys/filedesc.h and sys/socketvar.h. Requested by: bde Since locking sigio_lock is usually followed by calling pgsigio(), move the declaration of sigio_lock and the definitions of SIGIO_*() to sys/signalvar.h. While I am here, sort include files alphabetically, where possible.
2002-04-30 01:54:54 +00:00
#include <sys/signalvar.h>
#include <sys/sx.h>
#include <sys/systm.h>
Add and move declarations to fix all of the warnings from `gcc -Wimplicit' (except in netccitt, netiso and netns) and most of the warnings from `gcc -Wnested-externs'. Fix all the bugs found. There were no serious ones.
1995-03-16 18:17:34 +00:00
#include <sys/un.h>
Revert the change of #includes in sys/filedesc.h and sys/socketvar.h. Requested by: bde Since locking sigio_lock is usually followed by calling pgsigio(), move the declaration of sigio_lock and the definitions of SIGIO_*() to sys/signalvar.h. While I am here, sort include files alphabetically, where possible.
2002-04-30 01:54:54 +00:00
#include <sys/unistd.h>
#include <sys/vnode.h>
BSD 4.4 Lite Kernel Sources
1994-05-24 10:09:53 +00:00
/*
Back out fifo_vnops.c:1.127, which introduced an sx lock around I/O on a fifo. While this did indeed close the race, confirming suspicions about the nature of the problem, it causes difficulties with blocking I/O on fifos. Discussed with: ups Also spotted by: Peter Holm <peter at holm dot cc>
2005-09-27 16:45:22 +00:00
* This structure is associated with the FIFO vnode and stores
* the state associated with the FIFO.
- Improve comments about locking of the "struct fifoinfo" which is a bit unclear. - Fix a memory leak [0] [0] Diagnosed by: Dorr H. Clark <dclark at engr dot scu dot edu> MFC: 1 week
2009-11-06 22:29:46 +00:00
* Notes about locking:
merge pipe and fifo implementations Also reviewed by: jhb, jilles (initial revision) Tested by: pho, jilles Submitted by: gianni Reviewed by: bde
2012-02-23 18:37:30 +00:00
* - fi_pipe is invariant since init time.
* - fi_readers and fi_writers are protected by the vnode lock.
BSD 4.4 Lite Kernel Sources
1994-05-24 10:09:53 +00:00
*/
struct fifoinfo {
merge pipe and fifo implementations Also reviewed by: jhb, jilles (initial revision) Tested by: pho, jilles Submitted by: gianni Reviewed by: bde
2012-02-23 18:37:30 +00:00
struct pipe *fi_pipe;
long fi_readers;
long fi_writers;
Ensure that when a blockable open of fifo returns success, a valid file descriptor opened for complimentary access exists as well. The implementation of the guarantee is done by counting the generations of readers and writers opens. We return success and not EINTR or ERESTART error, when the sleep for complimentary opening is interrupted, but the generation was changed during the sleep. Longer explanation: assume there are two threads, A doing open("fifo", O_RDONLY) and B doing open("fifo", O_WRONLY), and no other threads either trying to open the fifo, nor there are any file descriptors referencing the fifo. Before the change, it was possible e.g. for for thread A to return a valid file descriptor, while thread B returned EINTR if a signal to B was delivered simultaneously with the wakeup from A. After the change, in this situation both A::open() and B::open() succeed and the signal is made "as if" it was noticed slightly later. Note that the signal actual delivery is not changed, it is done by ast on syscall return path, so signal handler is still executed before first instruction after syscall. See PR for the code demonstrating the issue. PR: 203162 Reported by: Victor Stinner victor.stinner@gmail.com Reviewed by: jilles Tested by: bapt, pho Sponsored by: The FreeBSD Foundation MFC after: 1 week
2015-09-20 21:18:33 +00:00
u_int fi_rgen;
u_int fi_wgen;
BSD 4.4 Lite Kernel Sources
1994-05-24 10:09:53 +00:00
};
Mechanically change prototypes for vnode operations to use the new typedefs.
2004-12-01 12:24:41 +00:00
static vop_print_t fifo_print;
static vop_open_t fifo_open;
static vop_close_t fifo_close;
static vop_advlock_t fifo_advlock;
vnops megacommit 1. Use the default function to access all the specfs operations. 2. Use the default function to access all the fifofs operations. 3. Use the default function to access all the ufs operations. 4. Fix VCALL usage in vfs_cache.c 5. Use VOCALL to access specfs functions in devfs_vnops.c 6. Staticize most of the spec and fifofs vnops functions. 7. Make UFS panic if it lacks bits of the underlying storage handling.
1997-10-15 13:24:07 +00:00
Back when VOP_* was introduced, we did not have new-style struct initializations but we did have lofty goals and big ideals. Adjust to more contemporary circumstances and gain type checking. Replace the entire vop_t frobbing thing with properly typed structures. The only casualty is that we can not add a new VOP_ method with a loadable module. History has not given us reason to belive this would ever be feasible in the the first place. Eliminate in toto VOCALL(), vop_t, VNODEOP_SET() etc. Give coda correct prototypes and function definitions for all vop_()s. Generate a bit more data from the vnode_if.src file: a struct vop_vector and protype typedefs for all vop methods. Add a new vop_bypass() and make vop_default be a pointer to another struct vop_vector. Remove a lot of vfs_init since vop_vector is ready to use from the compiler. Cast various vop_mumble() to void * with uppercase name, for instance VOP_PANIC, VOP_NULL etc. Implement VCALL() by making vdesc_offset the offsetof() the relevant function pointer in vop_vector. This is disgusting but since the code is generated by a script comparatively safe. The alternative for nullfs etc. would be much worse. Fix up all vnode method vectors to remove casts so they become typesafe. (The bulk of this is generated by scripts)
2004-12-01 23:16:38 +00:00
struct vop_vector fifo_specops = {
.vop_default = &default_vnodeops,
Whitespace in vop_vector{} initializations.
2005-01-13 18:59:48 +00:00
Back when VOP_* was introduced, we did not have new-style struct initializations but we did have lofty goals and big ideals. Adjust to more contemporary circumstances and gain type checking. Replace the entire vop_t frobbing thing with properly typed structures. The only casualty is that we can not add a new VOP_ method with a loadable module. History has not given us reason to belive this would ever be feasible in the the first place. Eliminate in toto VOCALL(), vop_t, VNODEOP_SET() etc. Give coda correct prototypes and function definitions for all vop_()s. Generate a bit more data from the vnode_if.src file: a struct vop_vector and protype typedefs for all vop methods. Add a new vop_bypass() and make vop_default be a pointer to another struct vop_vector. Remove a lot of vfs_init since vop_vector is ready to use from the compiler. Cast various vop_mumble() to void * with uppercase name, for instance VOP_PANIC, VOP_NULL etc. Implement VCALL() by making vdesc_offset the offsetof() the relevant function pointer in vop_vector. This is disgusting but since the code is generated by a script comparatively safe. The alternative for nullfs etc. would be much worse. Fix up all vnode method vectors to remove casts so they become typesafe. (The bulk of this is generated by scripts)
2004-12-01 23:16:38 +00:00
.vop_advlock = fifo_advlock,
.vop_close = fifo_close,
.vop_create = VOP_PANIC,
.vop_getattr = VOP_EBADF,
Remove unused VOP_IOCTL and VOP_KQFILTER implementations for fifofs. MFC after: 2 weeks
2009-06-10 14:02:22 +00:00
.vop_ioctl = VOP_PANIC,
.vop_kqfilter = VOP_PANIC,
Back when VOP_* was introduced, we did not have new-style struct initializations but we did have lofty goals and big ideals. Adjust to more contemporary circumstances and gain type checking. Replace the entire vop_t frobbing thing with properly typed structures. The only casualty is that we can not add a new VOP_ method with a loadable module. History has not given us reason to belive this would ever be feasible in the the first place. Eliminate in toto VOCALL(), vop_t, VNODEOP_SET() etc. Give coda correct prototypes and function definitions for all vop_()s. Generate a bit more data from the vnode_if.src file: a struct vop_vector and protype typedefs for all vop methods. Add a new vop_bypass() and make vop_default be a pointer to another struct vop_vector. Remove a lot of vfs_init since vop_vector is ready to use from the compiler. Cast various vop_mumble() to void * with uppercase name, for instance VOP_PANIC, VOP_NULL etc. Implement VCALL() by making vdesc_offset the offsetof() the relevant function pointer in vop_vector. This is disgusting but since the code is generated by a script comparatively safe. The alternative for nullfs etc. would be much worse. Fix up all vnode method vectors to remove casts so they become typesafe. (The bulk of this is generated by scripts)
2004-12-01 23:16:38 +00:00
.vop_link = VOP_PANIC,
.vop_mkdir = VOP_PANIC,
.vop_mknod = VOP_PANIC,
.vop_open = fifo_open,
Rework pathconf handling for FIFOs. On the one hand, FIFOs should respect other variables not supported by the fifofs vnode operation (such as _PC_NAME_MAX, _PC_LINK_MAX, etc.). These values are fs-specific and must come from a fs-specific method. On the other hand, filesystems that support FIFOs are required to support _PC_PIPE_BUF on directory vnodes that can contain FIFOs. Given this latter requirement, once the fs-specific VOP_PATHCONF method supports _PC_PIPE_BUF for directories, it is also suitable for FIFOs permitting a single VOP_PATHCONF method to be used for both FIFOs and non-FIFOs. To that end, retire all of the FIFO-specific pathconf methods from filesystems and change FIFO-specific vnode operation switches to use the existing fs-specific VOP_PATHCONF method. For fifofs, set it's VOP_PATHCONF to VOP_PANIC since it should no longer be used. While here, move _PC_PIPE_BUF handling out of vop_stdpathconf() so that only filesystems supporting FIFOs will report a value. In addition, only report a valid _PC_PIPE_BUF for directories and FIFOs. Discussed with: bde Reviewed by: kib (part of a larger patch) MFC after: 1 month Sponsored by: Chelsio Communications Differential Revision: https://reviews.freebsd.org/D12572
2017-12-19 22:39:05 +00:00
.vop_pathconf = VOP_PANIC,
Back when VOP_* was introduced, we did not have new-style struct initializations but we did have lofty goals and big ideals. Adjust to more contemporary circumstances and gain type checking. Replace the entire vop_t frobbing thing with properly typed structures. The only casualty is that we can not add a new VOP_ method with a loadable module. History has not given us reason to belive this would ever be feasible in the the first place. Eliminate in toto VOCALL(), vop_t, VNODEOP_SET() etc. Give coda correct prototypes and function definitions for all vop_()s. Generate a bit more data from the vnode_if.src file: a struct vop_vector and protype typedefs for all vop methods. Add a new vop_bypass() and make vop_default be a pointer to another struct vop_vector. Remove a lot of vfs_init since vop_vector is ready to use from the compiler. Cast various vop_mumble() to void * with uppercase name, for instance VOP_PANIC, VOP_NULL etc. Implement VCALL() by making vdesc_offset the offsetof() the relevant function pointer in vop_vector. This is disgusting but since the code is generated by a script comparatively safe. The alternative for nullfs etc. would be much worse. Fix up all vnode method vectors to remove casts so they become typesafe. (The bulk of this is generated by scripts)
2004-12-01 23:16:38 +00:00
.vop_print = fifo_print,
Explicitly panic vop_read/vop_write on fifos.
2004-12-13 07:07:50 +00:00
.vop_read = VOP_PANIC,
Back when VOP_* was introduced, we did not have new-style struct initializations but we did have lofty goals and big ideals. Adjust to more contemporary circumstances and gain type checking. Replace the entire vop_t frobbing thing with properly typed structures. The only casualty is that we can not add a new VOP_ method with a loadable module. History has not given us reason to belive this would ever be feasible in the the first place. Eliminate in toto VOCALL(), vop_t, VNODEOP_SET() etc. Give coda correct prototypes and function definitions for all vop_()s. Generate a bit more data from the vnode_if.src file: a struct vop_vector and protype typedefs for all vop methods. Add a new vop_bypass() and make vop_default be a pointer to another struct vop_vector. Remove a lot of vfs_init since vop_vector is ready to use from the compiler. Cast various vop_mumble() to void * with uppercase name, for instance VOP_PANIC, VOP_NULL etc. Implement VCALL() by making vdesc_offset the offsetof() the relevant function pointer in vop_vector. This is disgusting but since the code is generated by a script comparatively safe. The alternative for nullfs etc. would be much worse. Fix up all vnode method vectors to remove casts so they become typesafe. (The bulk of this is generated by scripts)
2004-12-01 23:16:38 +00:00
.vop_readdir = VOP_PANIC,
.vop_readlink = VOP_PANIC,
.vop_reallocblks = VOP_PANIC,
.vop_reclaim = VOP_NULL,
.vop_remove = VOP_PANIC,
.vop_rename = VOP_PANIC,
.vop_rmdir = VOP_PANIC,
.vop_setattr = VOP_EBADF,
.vop_symlink = VOP_PANIC,
Explicitly panic vop_read/vop_write on fifos.
2004-12-13 07:07:50 +00:00
.vop_write = VOP_PANIC,
BSD 4.4 Lite Kernel Sources
1994-05-24 10:09:53 +00:00
};
Implemented loadable VFS modules, and made most existing filesystems loadable. (NFS is a notable exception.)
1994-09-21 03:47:43 +00:00
If fifo_open() is interrupted, fifo_close() may not get called, causing a resource leak. Move the resource deallocation code from fifo_close() to a new function, fifo_cleanup(), and call fifo_cleanup() from fifo_close() and the appropriate places in fifo_open(). Tested by: Lukas Ertl Pointy hat to: truckman
2003-11-10 22:21:00 +00:00
/*
* Dispose of fifo resources.
*/
static void
fifo_cleanup(struct vnode *vp)
{
merge pipe and fifo implementations Also reviewed by: jhb, jilles (initial revision) Tested by: pho, jilles Submitted by: gianni Reviewed by: bde
2012-02-23 18:37:30 +00:00
struct fifoinfo *fip;
If fifo_open() is interrupted, fifo_close() may not get called, causing a resource leak. Move the resource deallocation code from fifo_close() to a new function, fifo_cleanup(), and call fifo_cleanup() from fifo_close() and the appropriate places in fifo_open(). Tested by: Lukas Ertl Pointy hat to: truckman
2003-11-10 22:21:00 +00:00
Assert an exclusive vnode lock for fifo_cleanup() and fifo_close() since they change v_fifoinfo. Discussed with: ups (a while ago)
2009-01-28 18:10:57 +00:00
ASSERT_VOP_ELOCKED(vp, "fifo_cleanup");
merge pipe and fifo implementations Also reviewed by: jhb, jilles (initial revision) Tested by: pho, jilles Submitted by: gianni Reviewed by: bde
2012-02-23 18:37:30 +00:00
fip = vp->v_fifoinfo;
Use "fip->fi_readers == 0 && fip->fi_writers == 0" as the condition for disposing fifo resources in fifo_cleanup() instead using of "vp->v_usecount == 1". There may be other references to the vnode, for instance by nullfs, at the time fifo_open() or fifo_close() is called, which could cause a resource leak. Don't bother grabbing the vnode interlock in fifo_cleanup() since it no longer accesses v_usecount.
2003-11-16 01:11:11 +00:00
if (fip->fi_readers == 0 && fip->fi_writers == 0) {
If fifo_open() is interrupted, fifo_close() may not get called, causing a resource leak. Move the resource deallocation code from fifo_close() to a new function, fifo_cleanup(), and call fifo_cleanup() from fifo_close() and the appropriate places in fifo_open(). Tested by: Lukas Ertl Pointy hat to: truckman
2003-11-10 22:21:00 +00:00
vp->v_fifoinfo = NULL;
merge pipe and fifo implementations Also reviewed by: jhb, jilles (initial revision) Tested by: pho, jilles Submitted by: gianni Reviewed by: bde
2012-02-23 18:37:30 +00:00
pipe_dtor(fip->fi_pipe);
Retire the MALLOC and FREE macros. They are an abomination unto style(9). MFC after: 3 months
2008-10-23 15:53:51 +00:00
free(fip, M_VNODE);
Use "fip->fi_readers == 0 && fip->fi_writers == 0" as the condition for disposing fifo resources in fifo_cleanup() instead using of "vp->v_usecount == 1". There may be other references to the vnode, for instance by nullfs, at the time fifo_open() or fifo_close() is called, which could cause a resource leak. Don't bother grabbing the vnode interlock in fifo_cleanup() since it no longer accesses v_usecount.
2003-11-16 01:11:11 +00:00
}
If fifo_open() is interrupted, fifo_close() may not get called, causing a resource leak. Move the resource deallocation code from fifo_close() to a new function, fifo_cleanup(), and call fifo_cleanup() from fifo_close() and the appropriate places in fifo_open(). Tested by: Lukas Ertl Pointy hat to: truckman
2003-11-10 22:21:00 +00:00
}
BSD 4.4 Lite Kernel Sources
1994-05-24 10:09:53 +00:00
/*
* Open called to set up a new instance of a fifo or
* to find an active instance of a fifo.
*/
/* ARGSUSED */
vnops megacommit 1. Use the default function to access all the specfs operations. 2. Use the default function to access all the fifofs operations. 3. Use the default function to access all the ufs operations. 4. Fix VCALL usage in vfs_cache.c 5. Use VOCALL to access specfs functions in devfs_vnops.c 6. Staticize most of the spec and fifofs vnops functions. 7. Make UFS panic if it lacks bits of the underlying storage handling.
1997-10-15 13:24:07 +00:00
static int
BSD 4.4 Lite Kernel Sources
1994-05-24 10:09:53 +00:00
fifo_open(ap)
struct vop_open_args /* {
struct vnode *a_vp;
int a_mode;
struct ucred *a_cred;
KSE Milestone 2 Note ALL MODULES MUST BE RECOMPILED make the kernel aware that there are smaller units of scheduling than the process. (but only allow one thread per process at this time). This is functionally equivalent to teh previousl -current except that there is a thread associated with each process. Sorry john! (your next MFC will be a doosie!) Reviewed by: peter@freebsd.org, dillon@freebsd.org X-MFC after: ha ha ha ha
2001-09-12 08:38:13 +00:00
struct thread *a_td;
s/a_fdidx/a_fp/ for VOP_OPEN comments that inline struct vop_open_args definition. Discussed with: bde MFC after: 2 weeks
2009-06-10 14:09:05 +00:00
struct file *a_fp;
BSD 4.4 Lite Kernel Sources
1994-05-24 10:09:53 +00:00
} */ *ap;
{
merge pipe and fifo implementations Also reviewed by: jhb, jilles (initial revision) Tested by: pho, jilles Submitted by: gianni Reviewed by: bde
2012-02-23 18:37:30 +00:00
struct vnode *vp;
struct file *fp;
struct thread *td;
This is the kernel Lite/2 commit. There are some requisite userland changes, so don't expect to be able to run the kernel as-is (very well) without the appropriate Lite/2 userland changes. The system boots and can mount UFS filesystems. Untested: ext2fs, msdosfs, NFS Known problems: Incorrect Berkeley ID strings in some files. Mount_std mounts will not work until the getfsent library routine is changed. Reviewed by: various people Submitted by: Jeffery Hsu <hsu@freebsd.org>
1997-02-10 02:22:35 +00:00
struct fifoinfo *fip;
merge pipe and fifo implementations Also reviewed by: jhb, jilles (initial revision) Tested by: pho, jilles Submitted by: gianni Reviewed by: bde
2012-02-23 18:37:30 +00:00
struct pipe *fpipe;
Ensure that when a blockable open of fifo returns success, a valid file descriptor opened for complimentary access exists as well. The implementation of the guarantee is done by counting the generations of readers and writers opens. We return success and not EINTR or ERESTART error, when the sleep for complimentary opening is interrupted, but the generation was changed during the sleep. Longer explanation: assume there are two threads, A doing open("fifo", O_RDONLY) and B doing open("fifo", O_WRONLY), and no other threads either trying to open the fifo, nor there are any file descriptors referencing the fifo. Before the change, it was possible e.g. for for thread A to return a valid file descriptor, while thread B returned EINTR if a signal to B was delivered simultaneously with the wakeup from A. After the change, in this situation both A::open() and B::open() succeed and the signal is made "as if" it was noticed slightly later. Note that the signal actual delivery is not changed, it is done by ast on syscall return path, so signal handler is still executed before first instruction after syscall. See PR for the code demonstrating the issue. PR: 203162 Reported by: Victor Stinner victor.stinner@gmail.com Reviewed by: jilles Tested by: bapt, pho Sponsored by: The FreeBSD Foundation MFC after: 1 week
2015-09-20 21:18:33 +00:00
u_int gen;
Make SIGSTOP working for sleeps done while waiting for fifo readers or writers in open(2), when the fifo is located on an NFS mount. Reported by: bde Sponsored by: The FreeBSD Foundation MFC after: 1 week
2015-01-18 15:03:26 +00:00
int error, stops_deferred;
BSD 4.4 Lite Kernel Sources
1994-05-24 10:09:53 +00:00
merge pipe and fifo implementations Also reviewed by: jhb, jilles (initial revision) Tested by: pho, jilles Submitted by: gianni Reviewed by: bde
2012-02-23 18:37:30 +00:00
vp = ap->a_vp;
fp = ap->a_fp;
td = ap->a_td;
When we do open, we should lock the vnode exclusively. This fixes few races: - fifo race, where two threads assign v_fifoinfo, - v_writecount modifications, - v_object modifications, - and probably more... Discussed with: kib, ups Approved by: re (rwatson)
2007-07-26 16:58:09 +00:00
ASSERT_VOP_ELOCKED(vp, "fifo_open");
Do not allow O_EXEC opens for fifo, return EINVAL. Besides not making sense, open(O_EXEC) for fifo creates fifoinfo with zero readers and writers counts, which causes premature free of pipes. Reported and tested by: pho Sponsored by: The FreeBSD Foundation MFC after: 1 week
2013-12-17 17:28:02 +00:00
if (fp == NULL || (ap->a_mode & FEXEC) != 0)
If fifo_open() is called with a negative file descriptor, return EINVAL rather than panicking later. This can occur if the kernel calls vn_open() on a fifo, as there will be no associated file descriptor, and therefore the file descriptor operations cannot be modified to point to the fifo operation set. MFC after: 3 days Reported by: Martin <nakal at nurfuerspam dot de> PR: 94278
2006-03-14 19:29:45 +00:00
return (EINVAL);
BSD 4.4 Lite Kernel Sources
1994-05-24 10:09:53 +00:00
if ((fip = vp->v_fifoinfo) == NULL) {
Ignore the error from pipespace_new when creating a pipe. It can fail if pipe map is exhausted (as a result of too many pipes created), but it is not fatal and could be provoked by unprivileged users. The only consequence is worse performance with given pipe. Reported by: ivoras Suggested by: kib MFC after: 1 week
2014-05-02 00:52:13 +00:00
pipe_named_ctor(&fpipe, td);
merge pipe and fifo implementations Also reviewed by: jhb, jilles (initial revision) Tested by: pho, jilles Submitted by: gianni Reviewed by: bde
2012-02-23 18:37:30 +00:00
fip = malloc(sizeof(*fip), M_VNODE, M_WAITOK);
fip->fi_pipe = fpipe;
I am comparing current pipe code with the one in 8.3-STABLE r236165, I found 8.3 is a history BSD version using socket to implement FIFO pipe, it uses per-file seqcount to compare with writer generation stored in per-pipe object. The concept is after all writers are gone, the pipe enters next generation, all old readers have not closed the pipe should get the indication that the pipe is disconnected, result is they should get EPIPE, SIGPIPE or get POLLHUP in poll(). But newcomer should not know that previous writters were gone, it should treat it as a fresh session. I am trying to bring back FIFO pipe to history behavior. It is still unclear that if single EOF flag can represent SBS_CANTSENDMORE and SBS_CANTRCVMORE which socket-based version is using, but I have run the poll regression test in tool directory, output is same as the one on 8.3-STABLE now. I think the output "not ok 18 FIFO state 6b: poll result 0 expected 1. expected POLLHUP; got 0" might be bogus, because newcomer should not know that old writers were gone. I got the same behavior on Linux. Our implementation always return POLLIN for disconnected pipe even it should return POLLHUP, but I think it is not wise to remove POLLIN for compatible reason, this is our history behavior. Regression test: /usr/src/tools/regression/poll
2012-07-31 05:48:35 +00:00
fpipe->pipe_wgen = fip->fi_readers = fip->fi_writers = 0;
merge pipe and fifo implementations Also reviewed by: jhb, jilles (initial revision) Tested by: pho, jilles Submitted by: gianni Reviewed by: bde
2012-02-23 18:37:30 +00:00
KASSERT(vp->v_fifoinfo == NULL, ("fifo_open: v_fifoinfo race"));
Clean up the fifo_open() implementation: Restructure the error handling portion of the resource allocation code to eliminate duplicated code. Test for the O_NONBLOCK && fi_readers == 0 case before incrementing fi_writers and modifying the the socket flag to avoid having to undo these operations in this error case. Restructure and simplify the code that handles blocking opens. There should be no change to functionality.
2003-06-13 06:58:11 +00:00
vp->v_fifoinfo = fip;
BSD 4.4 Lite Kernel Sources
1994-05-24 10:09:53 +00:00
}
merge pipe and fifo implementations Also reviewed by: jhb, jilles (initial revision) Tested by: pho, jilles Submitted by: gianni Reviewed by: bde
2012-02-23 18:37:30 +00:00
fpipe = fip->fi_pipe;
KASSERT(fpipe != NULL, ("fifo_open: pipe is NULL"));
Fix up locking problems in fifo_open() and fifo_close(): Sleep on the vnode interlock while waiting for another caller to increment fi_readers or fi_writers. Hold the vnode interlock while incrementing fi_readers or fi_writers to prevent a wakeup from being missed. Only access fi_readers and fi_writers while holding the vnode lock. Previously fifo_close() decremented their values without holding a lock. Move resource deallocation from fifo_close() to fifo_inactive(), which allows the VOP_CLOSE() call in the error return path in fifo_open() to be removed. Fifo_open() was calling VOP_CLOSE() with the vnode lock held, in violation the current vnode locking API. Also the way fifo_close() used vrefcnt() to decide whether to deallocate resources was bogus according to comments in the vrefcnt() implementation. Reviewed by: bde
2003-06-01 06:24:32 +00:00
/*
merge pipe and fifo implementations Also reviewed by: jhb, jilles (initial revision) Tested by: pho, jilles Submitted by: gianni Reviewed by: bde
2012-02-23 18:37:30 +00:00
* Use the pipe mutex here, in addition to the vnode lock,
- Improve comments about locking of the "struct fifoinfo" which is a bit unclear. - Fix a memory leak [0] [0] Diagnosed by: Dorr H. Clark <dclark at engr dot scu dot edu> MFC: 1 week
2009-11-06 22:29:46 +00:00
* in order to allow vnode lock dropping before msleep() calls
* and still avoiding missed wakeups.
Fix up locking problems in fifo_open() and fifo_close(): Sleep on the vnode interlock while waiting for another caller to increment fi_readers or fi_writers. Hold the vnode interlock while incrementing fi_readers or fi_writers to prevent a wakeup from being missed. Only access fi_readers and fi_writers while holding the vnode lock. Previously fifo_close() decremented their values without holding a lock. Move resource deallocation from fifo_close() to fifo_inactive(), which allows the VOP_CLOSE() call in the error return path in fifo_open() to be removed. Fifo_open() was calling VOP_CLOSE() with the vnode lock held, in violation the current vnode locking API. Also the way fifo_close() used vrefcnt() to decide whether to deallocate resources was bogus according to comments in the vrefcnt() implementation. Reviewed by: bde
2003-06-01 06:24:32 +00:00
*/
merge pipe and fifo implementations Also reviewed by: jhb, jilles (initial revision) Tested by: pho, jilles Submitted by: gianni Reviewed by: bde
2012-02-23 18:37:30 +00:00
PIPE_LOCK(fpipe);
This is the kernel Lite/2 commit. There are some requisite userland changes, so don't expect to be able to run the kernel as-is (very well) without the appropriate Lite/2 userland changes. The system boots and can mount UFS filesystems. Untested: ext2fs, msdosfs, NFS Known problems: Incorrect Berkeley ID strings in some files. Mount_std mounts will not work until the getfsent library routine is changed. Reviewed by: various people Submitted by: Jeffery Hsu <hsu@freebsd.org>
1997-02-10 02:22:35 +00:00
if (ap->a_mode & FREAD) {
fip->fi_readers++;
Ensure that when a blockable open of fifo returns success, a valid file descriptor opened for complimentary access exists as well. The implementation of the guarantee is done by counting the generations of readers and writers opens. We return success and not EINTR or ERESTART error, when the sleep for complimentary opening is interrupted, but the generation was changed during the sleep. Longer explanation: assume there are two threads, A doing open("fifo", O_RDONLY) and B doing open("fifo", O_WRONLY), and no other threads either trying to open the fifo, nor there are any file descriptors referencing the fifo. Before the change, it was possible e.g. for for thread A to return a valid file descriptor, while thread B returned EINTR if a signal to B was delivered simultaneously with the wakeup from A. After the change, in this situation both A::open() and B::open() succeed and the signal is made "as if" it was noticed slightly later. Note that the signal actual delivery is not changed, it is done by ast on syscall return path, so signal handler is still executed before first instruction after syscall. See PR for the code demonstrating the issue. PR: 203162 Reported by: Victor Stinner victor.stinner@gmail.com Reviewed by: jilles Tested by: bapt, pho Sponsored by: The FreeBSD Foundation MFC after: 1 week
2015-09-20 21:18:33 +00:00
fip->fi_rgen++;
This is the kernel Lite/2 commit. There are some requisite userland changes, so don't expect to be able to run the kernel as-is (very well) without the appropriate Lite/2 userland changes. The system boots and can mount UFS filesystems. Untested: ext2fs, msdosfs, NFS Known problems: Incorrect Berkeley ID strings in some files. Mount_std mounts will not work until the getfsent library routine is changed. Reviewed by: various people Submitted by: Jeffery Hsu <hsu@freebsd.org>
1997-02-10 02:22:35 +00:00
if (fip->fi_readers == 1) {
merge pipe and fifo implementations Also reviewed by: jhb, jilles (initial revision) Tested by: pho, jilles Submitted by: gianni Reviewed by: bde
2012-02-23 18:37:30 +00:00
fpipe->pipe_state &= ~PIPE_EOF;
if (fip->fi_writers > 0)
More low-hanging fruit: kill caddr_t in calls to wakeup(9) / [mt]sleep(9).
2003-03-02 16:54:40 +00:00
wakeup(&fip->fi_writers);
Allow a pipe to be opened read/write at one end, as is allowed in SunOS and SCO. You can then even use the pipe as a cheap fifo stack (yuck!). A semantic change also important (but not limited) to iBCS2 compatibility. Submitted by: swallace
1995-08-06 16:14:21 +00:00
}
fcntl: fix overflow when setting F_READAHEAD VOP_READ and VOP_WRITE take the seqcount in blocks in a 16-bit field. However, fcntl allows you to set the seqcount in bytes to any nonnegative 31-bit value. The result can be a 16-bit overflow, which will be sign-extended in functions like ffs_read. Fix this by sanitizing the argument in kern_fcntl. As a matter of policy, limit to IO_SEQMAX rather than INT16_MAX. Also, fifos have overloaded the f_seqcount field for a completely different purpose ever since r238936. Formalize that by using a union type. Reviewed by: cem MFC after: 2 weeks Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D20710
2019-06-20 23:07:20 +00:00
fp->f_pipegen = fpipe->pipe_wgen - fip->fi_writers;
This is the kernel Lite/2 commit. There are some requisite userland changes, so don't expect to be able to run the kernel as-is (very well) without the appropriate Lite/2 userland changes. The system boots and can mount UFS filesystems. Untested: ext2fs, msdosfs, NFS Known problems: Incorrect Berkeley ID strings in some files. Mount_std mounts will not work until the getfsent library routine is changed. Reviewed by: various people Submitted by: Jeffery Hsu <hsu@freebsd.org>
1997-02-10 02:22:35 +00:00
}
if (ap->a_mode & FWRITE) {
Clean up the fifo_open() implementation: Restructure the error handling portion of the resource allocation code to eliminate duplicated code. Test for the O_NONBLOCK && fi_readers == 0 case before incrementing fi_writers and modifying the the socket flag to avoid having to undo these operations in this error case. Restructure and simplify the code that handles blocking opens. There should be no change to functionality.
2003-06-13 06:58:11 +00:00
if ((ap->a_mode & O_NONBLOCK) && fip->fi_readers == 0) {
merge pipe and fifo implementations Also reviewed by: jhb, jilles (initial revision) Tested by: pho, jilles Submitted by: gianni Reviewed by: bde
2012-02-23 18:37:30 +00:00
PIPE_UNLOCK(fpipe);
- Improve comments about locking of the "struct fifoinfo" which is a bit unclear. - Fix a memory leak [0] [0] Diagnosed by: Dorr H. Clark <dclark at engr dot scu dot edu> MFC: 1 week
2009-11-06 22:29:46 +00:00
if (fip->fi_writers == 0)
fifo_cleanup(vp);
Clean up the fifo_open() implementation: Restructure the error handling portion of the resource allocation code to eliminate duplicated code. Test for the O_NONBLOCK && fi_readers == 0 case before incrementing fi_writers and modifying the the socket flag to avoid having to undo these operations in this error case. Restructure and simplify the code that handles blocking opens. There should be no change to functionality.
2003-06-13 06:58:11 +00:00
return (ENXIO);
}
This is the kernel Lite/2 commit. There are some requisite userland changes, so don't expect to be able to run the kernel as-is (very well) without the appropriate Lite/2 userland changes. The system boots and can mount UFS filesystems. Untested: ext2fs, msdosfs, NFS Known problems: Incorrect Berkeley ID strings in some files. Mount_std mounts will not work until the getfsent library routine is changed. Reviewed by: various people Submitted by: Jeffery Hsu <hsu@freebsd.org>
1997-02-10 02:22:35 +00:00
fip->fi_writers++;
Ensure that when a blockable open of fifo returns success, a valid file descriptor opened for complimentary access exists as well. The implementation of the guarantee is done by counting the generations of readers and writers opens. We return success and not EINTR or ERESTART error, when the sleep for complimentary opening is interrupted, but the generation was changed during the sleep. Longer explanation: assume there are two threads, A doing open("fifo", O_RDONLY) and B doing open("fifo", O_WRONLY), and no other threads either trying to open the fifo, nor there are any file descriptors referencing the fifo. Before the change, it was possible e.g. for for thread A to return a valid file descriptor, while thread B returned EINTR if a signal to B was delivered simultaneously with the wakeup from A. After the change, in this situation both A::open() and B::open() succeed and the signal is made "as if" it was noticed slightly later. Note that the signal actual delivery is not changed, it is done by ast on syscall return path, so signal handler is still executed before first instruction after syscall. See PR for the code demonstrating the issue. PR: 203162 Reported by: Victor Stinner victor.stinner@gmail.com Reviewed by: jilles Tested by: bapt, pho Sponsored by: The FreeBSD Foundation MFC after: 1 week
2015-09-20 21:18:33 +00:00
fip->fi_wgen++;
This is the kernel Lite/2 commit. There are some requisite userland changes, so don't expect to be able to run the kernel as-is (very well) without the appropriate Lite/2 userland changes. The system boots and can mount UFS filesystems. Untested: ext2fs, msdosfs, NFS Known problems: Incorrect Berkeley ID strings in some files. Mount_std mounts will not work until the getfsent library routine is changed. Reviewed by: various people Submitted by: Jeffery Hsu <hsu@freebsd.org>
1997-02-10 02:22:35 +00:00
if (fip->fi_writers == 1) {
merge pipe and fifo implementations Also reviewed by: jhb, jilles (initial revision) Tested by: pho, jilles Submitted by: gianni Reviewed by: bde
2012-02-23 18:37:30 +00:00
fpipe->pipe_state &= ~PIPE_EOF;
if (fip->fi_readers > 0)
More low-hanging fruit: kill caddr_t in calls to wakeup(9) / [mt]sleep(9).
2003-03-02 16:54:40 +00:00
wakeup(&fip->fi_readers);
Allow a pipe to be opened read/write at one end, as is allowed in SunOS and SCO. You can then even use the pipe as a cheap fifo stack (yuck!). A semantic change also important (but not limited) to iBCS2 compatibility. Submitted by: swallace
1995-08-06 16:14:21 +00:00
}
}
Clean up the fifo_open() implementation: Restructure the error handling portion of the resource allocation code to eliminate duplicated code. Test for the O_NONBLOCK && fi_readers == 0 case before incrementing fi_writers and modifying the the socket flag to avoid having to undo these operations in this error case. Restructure and simplify the code that handles blocking opens. There should be no change to functionality.
2003-06-13 06:58:11 +00:00
if ((ap->a_mode & O_NONBLOCK) == 0) {
if ((ap->a_mode & FREAD) && fip->fi_writers == 0) {
Ensure that when a blockable open of fifo returns success, a valid file descriptor opened for complimentary access exists as well. The implementation of the guarantee is done by counting the generations of readers and writers opens. We return success and not EINTR or ERESTART error, when the sleep for complimentary opening is interrupted, but the generation was changed during the sleep. Longer explanation: assume there are two threads, A doing open("fifo", O_RDONLY) and B doing open("fifo", O_WRONLY), and no other threads either trying to open the fifo, nor there are any file descriptors referencing the fifo. Before the change, it was possible e.g. for for thread A to return a valid file descriptor, while thread B returned EINTR if a signal to B was delivered simultaneously with the wakeup from A. After the change, in this situation both A::open() and B::open() succeed and the signal is made "as if" it was noticed slightly later. Note that the signal actual delivery is not changed, it is done by ast on syscall return path, so signal handler is still executed before first instruction after syscall. See PR for the code demonstrating the issue. PR: 203162 Reported by: Victor Stinner victor.stinner@gmail.com Reviewed by: jilles Tested by: bapt, pho Sponsored by: The FreeBSD Foundation MFC after: 1 week
2015-09-20 21:18:33 +00:00
gen = fip->fi_wgen;
VOP_LOCK1() (and so VOP_LOCK()) and VOP_UNLOCK() are only used in conjuction with 'thread' argument passing which is always curthread. Remove the unuseful extra-argument and pass explicitly curthread to lower layer functions, when necessary. KPI results broken by this change, which should affect several ports, so version bumping and manpage update will be further committed. Tested by: kris, pho, Diego Sardina <siarodx at gmail dot com>
2008-01-13 14:44:15 +00:00
VOP_UNLOCK(vp, 0);
Rewrite sigdeferstop(9) and sigallowstop(9) into more flexible framework allowing to set the suspension policy for the dynamic block. Extend the currently possible policies of stopping on interruptible sleeps and ignoring such sleeps by two more: do not suspend at interruptible sleeps, but interrupt them with either EINTR or ERESTART. Reviewed by: jilles Tested by: pho Sponsored by: The FreeBSD Foundation MFC after: 2 weeks Approved by: re (gjb)
2016-06-26 20:07:24 +00:00
stops_deferred = sigdeferstop(SIGDEFERSTOP_OFF);
merge pipe and fifo implementations Also reviewed by: jhb, jilles (initial revision) Tested by: pho, jilles Submitted by: gianni Reviewed by: bde
2012-02-23 18:37:30 +00:00
error = msleep(&fip->fi_readers, PIPE_MTX(fpipe),
Switch from using the vnode interlock to a private mutex in fifo_open() to avoid lock order problems when manipulating the sockets associated with the fifo. Minor optimization of a couple of calls to fifo_cleanup() from fifo_open().
2004-05-17 20:16:40 +00:00
PDROP | PCATCH | PSOCK, "fifoor", 0);
Rewrite sigdeferstop(9) and sigallowstop(9) into more flexible framework allowing to set the suspension policy for the dynamic block. Extend the currently possible policies of stopping on interruptible sleeps and ignoring such sleeps by two more: do not suspend at interruptible sleeps, but interrupt them with either EINTR or ERESTART. Reviewed by: jilles Tested by: pho Sponsored by: The FreeBSD Foundation MFC after: 2 weeks Approved by: re (gjb)
2016-06-26 20:07:24 +00:00
sigallowstop(stops_deferred);
vn_lock() is currently only used with the 'curthread' passed as argument. Remove this argument and pass curthread directly to underlying VOP_LOCK1() VFS method. This modify makes the code cleaner and in particular remove an annoying dependence helping next lockmgr() cleanup. KPI results, obviously, changed. Manpage and FreeBSD_version will be updated through further commits. As a side note, would be valuable to say that next commits will address a similar cleanup about VFS methods, in particular vop_lock1 and vop_unlock. Tested by: Diego Sardina <siarodx at gmail dot com>, Andrea Di Pasquale <whyx dot it at gmail dot com>
2008-01-10 01:10:58 +00:00
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
Ensure that when a blockable open of fifo returns success, a valid file descriptor opened for complimentary access exists as well. The implementation of the guarantee is done by counting the generations of readers and writers opens. We return success and not EINTR or ERESTART error, when the sleep for complimentary opening is interrupted, but the generation was changed during the sleep. Longer explanation: assume there are two threads, A doing open("fifo", O_RDONLY) and B doing open("fifo", O_WRONLY), and no other threads either trying to open the fifo, nor there are any file descriptors referencing the fifo. Before the change, it was possible e.g. for for thread A to return a valid file descriptor, while thread B returned EINTR if a signal to B was delivered simultaneously with the wakeup from A. After the change, in this situation both A::open() and B::open() succeed and the signal is made "as if" it was noticed slightly later. Note that the signal actual delivery is not changed, it is done by ast on syscall return path, so signal handler is still executed before first instruction after syscall. See PR for the code demonstrating the issue. PR: 203162 Reported by: Victor Stinner victor.stinner@gmail.com Reviewed by: jilles Tested by: bapt, pho Sponsored by: The FreeBSD Foundation MFC after: 1 week
2015-09-20 21:18:33 +00:00
if (error != 0 && gen == fip->fi_wgen) {
Fix up locking problems in fifo_open() and fifo_close(): Sleep on the vnode interlock while waiting for another caller to increment fi_readers or fi_writers. Hold the vnode interlock while incrementing fi_readers or fi_writers to prevent a wakeup from being missed. Only access fi_readers and fi_writers while holding the vnode lock. Previously fifo_close() decremented their values without holding a lock. Move resource deallocation from fifo_close() to fifo_inactive(), which allows the VOP_CLOSE() call in the error return path in fifo_open() to be removed. Fifo_open() was calling VOP_CLOSE() with the vnode lock held, in violation the current vnode locking API. Also the way fifo_close() used vrefcnt() to decide whether to deallocate resources was bogus according to comments in the vrefcnt() implementation. Reviewed by: bde
2003-06-01 06:24:32 +00:00
fip->fi_readers--;
Switch from using the vnode interlock to a private mutex in fifo_open() to avoid lock order problems when manipulating the sockets associated with the fifo. Minor optimization of a couple of calls to fifo_cleanup() from fifo_open().
2004-05-17 20:16:40 +00:00
if (fip->fi_readers == 0) {
merge pipe and fifo implementations Also reviewed by: jhb, jilles (initial revision) Tested by: pho, jilles Submitted by: gianni Reviewed by: bde
2012-02-23 18:37:30 +00:00
PIPE_LOCK(fpipe);
fpipe->pipe_state |= PIPE_EOF;
if (fpipe->pipe_state & PIPE_WANTW)
wakeup(fpipe);
PIPE_UNLOCK(fpipe);
Switch from using the vnode interlock to a private mutex in fifo_open() to avoid lock order problems when manipulating the sockets associated with the fifo. Minor optimization of a couple of calls to fifo_cleanup() from fifo_open().
2004-05-17 20:16:40 +00:00
fifo_cleanup(vp);
}
Fix up locking problems in fifo_open() and fifo_close(): Sleep on the vnode interlock while waiting for another caller to increment fi_readers or fi_writers. Hold the vnode interlock while incrementing fi_readers or fi_writers to prevent a wakeup from being missed. Only access fi_readers and fi_writers while holding the vnode lock. Previously fifo_close() decremented their values without holding a lock. Move resource deallocation from fifo_close() to fifo_inactive(), which allows the VOP_CLOSE() call in the error return path in fifo_open() to be removed. Fifo_open() was calling VOP_CLOSE() with the vnode lock held, in violation the current vnode locking API. Also the way fifo_close() used vrefcnt() to decide whether to deallocate resources was bogus according to comments in the vrefcnt() implementation. Reviewed by: bde
2003-06-01 06:24:32 +00:00
return (error);
}
merge pipe and fifo implementations Also reviewed by: jhb, jilles (initial revision) Tested by: pho, jilles Submitted by: gianni Reviewed by: bde
2012-02-23 18:37:30 +00:00
PIPE_LOCK(fpipe);
Better fix for the problem addressed by rev.1.79: don't loop in fifo_open() waiting for another reader or writer if one arrived and departed while we were waiting (or a little earlier). Rev.1.79 broke blocking opens of fifos by making them time out after 1 second. This was bad for at least apsfilter. Tested by: "Simon 'corecode' Schubert" <corecode@corecode.ath.cx>, Alexander Leidinger <Alexander@leidinger.net>, phk MFC after: 4 weeks
2003-03-24 11:03:42 +00:00
/*
* We must have got woken up because we had a writer.
* That (and not still having one) is the condition
* that we must wait for.
*/
BSD 4.4 Lite Kernel Sources
1994-05-24 10:09:53 +00:00
}
Clean up the fifo_open() implementation: Restructure the error handling portion of the resource allocation code to eliminate duplicated code. Test for the O_NONBLOCK && fi_readers == 0 case before incrementing fi_writers and modifying the the socket flag to avoid having to undo these operations in this error case. Restructure and simplify the code that handles blocking opens. There should be no change to functionality.
2003-06-13 06:58:11 +00:00
if ((ap->a_mode & FWRITE) && fip->fi_readers == 0) {
Ensure that when a blockable open of fifo returns success, a valid file descriptor opened for complimentary access exists as well. The implementation of the guarantee is done by counting the generations of readers and writers opens. We return success and not EINTR or ERESTART error, when the sleep for complimentary opening is interrupted, but the generation was changed during the sleep. Longer explanation: assume there are two threads, A doing open("fifo", O_RDONLY) and B doing open("fifo", O_WRONLY), and no other threads either trying to open the fifo, nor there are any file descriptors referencing the fifo. Before the change, it was possible e.g. for for thread A to return a valid file descriptor, while thread B returned EINTR if a signal to B was delivered simultaneously with the wakeup from A. After the change, in this situation both A::open() and B::open() succeed and the signal is made "as if" it was noticed slightly later. Note that the signal actual delivery is not changed, it is done by ast on syscall return path, so signal handler is still executed before first instruction after syscall. See PR for the code demonstrating the issue. PR: 203162 Reported by: Victor Stinner victor.stinner@gmail.com Reviewed by: jilles Tested by: bapt, pho Sponsored by: The FreeBSD Foundation MFC after: 1 week
2015-09-20 21:18:33 +00:00
gen = fip->fi_rgen;
VOP_LOCK1() (and so VOP_LOCK()) and VOP_UNLOCK() are only used in conjuction with 'thread' argument passing which is always curthread. Remove the unuseful extra-argument and pass explicitly curthread to lower layer functions, when necessary. KPI results broken by this change, which should affect several ports, so version bumping and manpage update will be further committed. Tested by: kris, pho, Diego Sardina <siarodx at gmail dot com>
2008-01-13 14:44:15 +00:00
VOP_UNLOCK(vp, 0);
Rewrite sigdeferstop(9) and sigallowstop(9) into more flexible framework allowing to set the suspension policy for the dynamic block. Extend the currently possible policies of stopping on interruptible sleeps and ignoring such sleeps by two more: do not suspend at interruptible sleeps, but interrupt them with either EINTR or ERESTART. Reviewed by: jilles Tested by: pho Sponsored by: The FreeBSD Foundation MFC after: 2 weeks Approved by: re (gjb)
2016-06-26 20:07:24 +00:00
stops_deferred = sigdeferstop(SIGDEFERSTOP_OFF);
merge pipe and fifo implementations Also reviewed by: jhb, jilles (initial revision) Tested by: pho, jilles Submitted by: gianni Reviewed by: bde
2012-02-23 18:37:30 +00:00
error = msleep(&fip->fi_writers, PIPE_MTX(fpipe),
Switch from using the vnode interlock to a private mutex in fifo_open() to avoid lock order problems when manipulating the sockets associated with the fifo. Minor optimization of a couple of calls to fifo_cleanup() from fifo_open().
2004-05-17 20:16:40 +00:00
PDROP | PCATCH | PSOCK, "fifoow", 0);
Rewrite sigdeferstop(9) and sigallowstop(9) into more flexible framework allowing to set the suspension policy for the dynamic block. Extend the currently possible policies of stopping on interruptible sleeps and ignoring such sleeps by two more: do not suspend at interruptible sleeps, but interrupt them with either EINTR or ERESTART. Reviewed by: jilles Tested by: pho Sponsored by: The FreeBSD Foundation MFC after: 2 weeks Approved by: re (gjb)
2016-06-26 20:07:24 +00:00
sigallowstop(stops_deferred);
vn_lock() is currently only used with the 'curthread' passed as argument. Remove this argument and pass curthread directly to underlying VOP_LOCK1() VFS method. This modify makes the code cleaner and in particular remove an annoying dependence helping next lockmgr() cleanup. KPI results, obviously, changed. Manpage and FreeBSD_version will be updated through further commits. As a side note, would be valuable to say that next commits will address a similar cleanup about VFS methods, in particular vop_lock1 and vop_unlock. Tested by: Diego Sardina <siarodx at gmail dot com>, Andrea Di Pasquale <whyx dot it at gmail dot com>
2008-01-10 01:10:58 +00:00
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
Ensure that when a blockable open of fifo returns success, a valid file descriptor opened for complimentary access exists as well. The implementation of the guarantee is done by counting the generations of readers and writers opens. We return success and not EINTR or ERESTART error, when the sleep for complimentary opening is interrupted, but the generation was changed during the sleep. Longer explanation: assume there are two threads, A doing open("fifo", O_RDONLY) and B doing open("fifo", O_WRONLY), and no other threads either trying to open the fifo, nor there are any file descriptors referencing the fifo. Before the change, it was possible e.g. for for thread A to return a valid file descriptor, while thread B returned EINTR if a signal to B was delivered simultaneously with the wakeup from A. After the change, in this situation both A::open() and B::open() succeed and the signal is made "as if" it was noticed slightly later. Note that the signal actual delivery is not changed, it is done by ast on syscall return path, so signal handler is still executed before first instruction after syscall. See PR for the code demonstrating the issue. PR: 203162 Reported by: Victor Stinner victor.stinner@gmail.com Reviewed by: jilles Tested by: bapt, pho Sponsored by: The FreeBSD Foundation MFC after: 1 week
2015-09-20 21:18:33 +00:00
if (error != 0 && gen == fip->fi_rgen) {
Fix up locking problems in fifo_open() and fifo_close(): Sleep on the vnode interlock while waiting for another caller to increment fi_readers or fi_writers. Hold the vnode interlock while incrementing fi_readers or fi_writers to prevent a wakeup from being missed. Only access fi_readers and fi_writers while holding the vnode lock. Previously fifo_close() decremented their values without holding a lock. Move resource deallocation from fifo_close() to fifo_inactive(), which allows the VOP_CLOSE() call in the error return path in fifo_open() to be removed. Fifo_open() was calling VOP_CLOSE() with the vnode lock held, in violation the current vnode locking API. Also the way fifo_close() used vrefcnt() to decide whether to deallocate resources was bogus according to comments in the vrefcnt() implementation. Reviewed by: bde
2003-06-01 06:24:32 +00:00
fip->fi_writers--;
Switch from using the vnode interlock to a private mutex in fifo_open() to avoid lock order problems when manipulating the sockets associated with the fifo. Minor optimization of a couple of calls to fifo_cleanup() from fifo_open().
2004-05-17 20:16:40 +00:00
if (fip->fi_writers == 0) {
merge pipe and fifo implementations Also reviewed by: jhb, jilles (initial revision) Tested by: pho, jilles Submitted by: gianni Reviewed by: bde
2012-02-23 18:37:30 +00:00
PIPE_LOCK(fpipe);
fpipe->pipe_state |= PIPE_EOF;
if (fpipe->pipe_state & PIPE_WANTR)
wakeup(fpipe);
I am comparing current pipe code with the one in 8.3-STABLE r236165, I found 8.3 is a history BSD version using socket to implement FIFO pipe, it uses per-file seqcount to compare with writer generation stored in per-pipe object. The concept is after all writers are gone, the pipe enters next generation, all old readers have not closed the pipe should get the indication that the pipe is disconnected, result is they should get EPIPE, SIGPIPE or get POLLHUP in poll(). But newcomer should not know that previous writters were gone, it should treat it as a fresh session. I am trying to bring back FIFO pipe to history behavior. It is still unclear that if single EOF flag can represent SBS_CANTSENDMORE and SBS_CANTRCVMORE which socket-based version is using, but I have run the poll regression test in tool directory, output is same as the one on 8.3-STABLE now. I think the output "not ok 18 FIFO state 6b: poll result 0 expected 1. expected POLLHUP; got 0" might be bogus, because newcomer should not know that old writers were gone. I got the same behavior on Linux. Our implementation always return POLLIN for disconnected pipe even it should return POLLHUP, but I think it is not wise to remove POLLIN for compatible reason, this is our history behavior. Regression test: /usr/src/tools/regression/poll
2012-07-31 05:48:35 +00:00
fpipe->pipe_wgen++;
merge pipe and fifo implementations Also reviewed by: jhb, jilles (initial revision) Tested by: pho, jilles Submitted by: gianni Reviewed by: bde
2012-02-23 18:37:30 +00:00
PIPE_UNLOCK(fpipe);
Switch from using the vnode interlock to a private mutex in fifo_open() to avoid lock order problems when manipulating the sockets associated with the fifo. Minor optimization of a couple of calls to fifo_cleanup() from fifo_open().
2004-05-17 20:16:40 +00:00
fifo_cleanup(vp);
}
Clean up the fifo_open() implementation: Restructure the error handling portion of the resource allocation code to eliminate duplicated code. Test for the O_NONBLOCK && fi_readers == 0 case before incrementing fi_writers and modifying the the socket flag to avoid having to undo these operations in this error case. Restructure and simplify the code that handles blocking opens. There should be no change to functionality.
2003-06-13 06:58:11 +00:00
return (error);
BSD 4.4 Lite Kernel Sources
1994-05-24 10:09:53 +00:00
}
Clean up the fifo_open() implementation: Restructure the error handling portion of the resource allocation code to eliminate duplicated code. Test for the O_NONBLOCK && fi_readers == 0 case before incrementing fi_writers and modifying the the socket flag to avoid having to undo these operations in this error case. Restructure and simplify the code that handles blocking opens. There should be no change to functionality.
2003-06-13 06:58:11 +00:00
/*
* We must have got woken up because we had
* a reader. That (and not still having one)
* is the condition that we must wait for.
*/
merge pipe and fifo implementations Also reviewed by: jhb, jilles (initial revision) Tested by: pho, jilles Submitted by: gianni Reviewed by: bde
2012-02-23 18:37:30 +00:00
PIPE_LOCK(fpipe);
BSD 4.4 Lite Kernel Sources
1994-05-24 10:09:53 +00:00
}
}
merge pipe and fifo implementations Also reviewed by: jhb, jilles (initial revision) Tested by: pho, jilles Submitted by: gianni Reviewed by: bde
2012-02-23 18:37:30 +00:00
PIPE_UNLOCK(fpipe);
Revert UF_OPENING workaround for CURRENT. Change the VOP_OPEN(), vn_open() vnode operation and d_fdopen() cdev operation argument from being file descriptor index into the pointer to struct file. Proposed and reviewed by: jhb Reviewed by: daichi (unionfs) Approved by: re (kensmith)
2007-05-31 11:51:53 +00:00
KASSERT(fp != NULL, ("can't fifo/vnode bypass"));
Don't forget to bypass vnodes in corner cases. Found by: kkenn and ports/shell/zsh Thanks to: jeffr
2004-12-13 10:07:57 +00:00
KASSERT(fp->f_ops == &badfileops, ("not badfileops in fifo_open"));
merge pipe and fifo implementations Also reviewed by: jhb, jilles (initial revision) Tested by: pho, jilles Submitted by: gianni Reviewed by: bde
2012-02-23 18:37:30 +00:00
finit(fp, fp->f_flag, DTYPE_FIFO, fpipe, &pipeops);
Introduce no-op nosup fifo kqueue filter and detach routine, which are used when a read filter is requested on a write-only fifo descriptor, or a write filter is requested on a read-only fifo descriptor. This permits the filters to be registered, but never raises the event, which causes kqueue behavior for fifos to more closely match similar semantics for poll and select, which permit testing for the condition even though the condition will never be raised, and is consistent with POSIX's notion that a fifo has identical semantics to a one-way IPC channel created using pipe() on most operating systems. The fifo regression test suite can now run to completion on HEAD without errors. MFC after: 3 days
2005-09-12 19:59:12 +00:00
return (0);
}
BSD 4.4 Lite Kernel Sources
1994-05-24 10:09:53 +00:00
/*
* Device close routine
*/
/* ARGSUSED */
vnops megacommit 1. Use the default function to access all the specfs operations. 2. Use the default function to access all the fifofs operations. 3. Use the default function to access all the ufs operations. 4. Fix VCALL usage in vfs_cache.c 5. Use VOCALL to access specfs functions in devfs_vnops.c 6. Staticize most of the spec and fifofs vnops functions. 7. Make UFS panic if it lacks bits of the underlying storage handling.
1997-10-15 13:24:07 +00:00
static int
BSD 4.4 Lite Kernel Sources
1994-05-24 10:09:53 +00:00
fifo_close(ap)
struct vop_close_args /* {
struct vnode *a_vp;
int a_fflag;
struct ucred *a_cred;
KSE Milestone 2 Note ALL MODULES MUST BE RECOMPILED make the kernel aware that there are smaller units of scheduling than the process. (but only allow one thread per process at this time). This is functionally equivalent to teh previousl -current except that there is a thread associated with each process. Sorry john! (your next MFC will be a doosie!) Reviewed by: peter@freebsd.org, dillon@freebsd.org X-MFC after: ha ha ha ha
2001-09-12 08:38:13 +00:00
struct thread *a_td;
BSD 4.4 Lite Kernel Sources
1994-05-24 10:09:53 +00:00
} */ *ap;
{
merge pipe and fifo implementations Also reviewed by: jhb, jilles (initial revision) Tested by: pho, jilles Submitted by: gianni Reviewed by: bde
2012-02-23 18:37:30 +00:00
struct vnode *vp;
struct fifoinfo *fip;
struct pipe *cpipe;
Fix up locking problems in fifo_open() and fifo_close(): Sleep on the vnode interlock while waiting for another caller to increment fi_readers or fi_writers. Hold the vnode interlock while incrementing fi_readers or fi_writers to prevent a wakeup from being missed. Only access fi_readers and fi_writers while holding the vnode lock. Previously fifo_close() decremented their values without holding a lock. Move resource deallocation from fifo_close() to fifo_inactive(), which allows the VOP_CLOSE() call in the error return path in fifo_open() to be removed. Fifo_open() was calling VOP_CLOSE() with the vnode lock held, in violation the current vnode locking API. Also the way fifo_close() used vrefcnt() to decide whether to deallocate resources was bogus according to comments in the vrefcnt() implementation. Reviewed by: bde
2003-06-01 06:24:32 +00:00
merge pipe and fifo implementations Also reviewed by: jhb, jilles (initial revision) Tested by: pho, jilles Submitted by: gianni Reviewed by: bde
2012-02-23 18:37:30 +00:00
vp = ap->a_vp;
fip = vp->v_fifoinfo;
cpipe = fip->fi_pipe;
Assert an exclusive vnode lock for fifo_cleanup() and fifo_close() since they change v_fifoinfo. Discussed with: ups (a while ago)
2009-01-28 18:10:57 +00:00
ASSERT_VOP_ELOCKED(vp, "fifo_close");
Allow a pipe to be opened read/write at one end, as is allowed in SunOS and SCO. You can then even use the pipe as a cheap fifo stack (yuck!). A semantic change also important (but not limited) to iBCS2 compatibility. Submitted by: swallace
1995-08-06 16:14:21 +00:00
if (ap->a_fflag & FREAD) {
BSD 4.4 Lite Kernel Sources
1994-05-24 10:09:53 +00:00
fip->fi_readers--;
merge pipe and fifo implementations Also reviewed by: jhb, jilles (initial revision) Tested by: pho, jilles Submitted by: gianni Reviewed by: bde
2012-02-23 18:37:30 +00:00
if (fip->fi_readers == 0) {
PIPE_LOCK(cpipe);
cpipe->pipe_state |= PIPE_EOF;
When a thread is blocked in direct write state, it only sets PIPE_DIRECTW flag but not PIPE_WANTW, but FIFO pipe code does not understand this internal state, when a FIFO peer reader closes the pipe, it wants to notify the writer, it checks PIPE_WANTW, if not set, it skips calling wakeup(), so blocked writer never noticed the case, but in general, the writer should return from the syscall with EPIPE error code and may get SIGPIPE signal. Setting the PIPE_WANTW fixed problem, or you can turn off direct write, it should fix the problem too. This bug is found by PR/170203. Another bug in FIFO pipe code is when peer closes the pipe, another end which is being blocked in select() or poll() is not notified, it missed to call pipeselwakeup(). Third problem is found in poll regression test, the existing code can not pass 6b,6c,6d tests, but FreeBSD-4 works. This commit does not fix the problem, I still need to study more to find the cause. PR: 170203 Tested by: Garrett Copper &lt; yanegomi at gmail dot com &gt;
2012-07-31 02:00:37 +00:00
if ((cpipe->pipe_state & PIPE_WANTW)) {
cpipe->pipe_state &= ~PIPE_WANTW;
merge pipe and fifo implementations Also reviewed by: jhb, jilles (initial revision) Tested by: pho, jilles Submitted by: gianni Reviewed by: bde
2012-02-23 18:37:30 +00:00
wakeup(cpipe);
When a thread is blocked in direct write state, it only sets PIPE_DIRECTW flag but not PIPE_WANTW, but FIFO pipe code does not understand this internal state, when a FIFO peer reader closes the pipe, it wants to notify the writer, it checks PIPE_WANTW, if not set, it skips calling wakeup(), so blocked writer never noticed the case, but in general, the writer should return from the syscall with EPIPE error code and may get SIGPIPE signal. Setting the PIPE_WANTW fixed problem, or you can turn off direct write, it should fix the problem too. This bug is found by PR/170203. Another bug in FIFO pipe code is when peer closes the pipe, another end which is being blocked in select() or poll() is not notified, it missed to call pipeselwakeup(). Third problem is found in poll regression test, the existing code can not pass 6b,6c,6d tests, but FreeBSD-4 works. This commit does not fix the problem, I still need to study more to find the cause. PR: 170203 Tested by: Garrett Copper &lt; yanegomi at gmail dot com &gt;
2012-07-31 02:00:37 +00:00
}
pipeselwakeup(cpipe);
merge pipe and fifo implementations Also reviewed by: jhb, jilles (initial revision) Tested by: pho, jilles Submitted by: gianni Reviewed by: bde
2012-02-23 18:37:30 +00:00
PIPE_UNLOCK(cpipe);
}
BSD 4.4 Lite Kernel Sources
1994-05-24 10:09:53 +00:00
}
This is the kernel Lite/2 commit. There are some requisite userland changes, so don't expect to be able to run the kernel as-is (very well) without the appropriate Lite/2 userland changes. The system boots and can mount UFS filesystems. Untested: ext2fs, msdosfs, NFS Known problems: Incorrect Berkeley ID strings in some files. Mount_std mounts will not work until the getfsent library routine is changed. Reviewed by: various people Submitted by: Jeffery Hsu <hsu@freebsd.org>
1997-02-10 02:22:35 +00:00
if (ap->a_fflag & FWRITE) {
fip->fi_writers--;
Fix poll(2) and select(2) for named pipes to return "ready for read" when all writers, observed by reader, exited. Use writer generation counter for fifo, and store the snapshot of the fifo generation in the f_seqcount field of struct file, that is otherwise unused for fifos. Set FreeBSD-undocumented POLLINIGNEOF flag only when file f_seqcount is equal to fifo' fi_wgen, and revert r89376. Fix POLLINIGNEOF for sockets and pipes, and return POLLHUP for them. Note that the patch does not fix not returning POLLHUP for fifos. PR: kern/94772 Submitted by: bde (original version) Reviewed by: rwatson, jilles Approved by: re (kensmith) MFC after: 6 weeks (might be)
2009-07-07 09:43:44 +00:00
if (fip->fi_writers == 0) {
merge pipe and fifo implementations Also reviewed by: jhb, jilles (initial revision) Tested by: pho, jilles Submitted by: gianni Reviewed by: bde
2012-02-23 18:37:30 +00:00
PIPE_LOCK(cpipe);
cpipe->pipe_state |= PIPE_EOF;
When a thread is blocked in direct write state, it only sets PIPE_DIRECTW flag but not PIPE_WANTW, but FIFO pipe code does not understand this internal state, when a FIFO peer reader closes the pipe, it wants to notify the writer, it checks PIPE_WANTW, if not set, it skips calling wakeup(), so blocked writer never noticed the case, but in general, the writer should return from the syscall with EPIPE error code and may get SIGPIPE signal. Setting the PIPE_WANTW fixed problem, or you can turn off direct write, it should fix the problem too. This bug is found by PR/170203. Another bug in FIFO pipe code is when peer closes the pipe, another end which is being blocked in select() or poll() is not notified, it missed to call pipeselwakeup(). Third problem is found in poll regression test, the existing code can not pass 6b,6c,6d tests, but FreeBSD-4 works. This commit does not fix the problem, I still need to study more to find the cause. PR: 170203 Tested by: Garrett Copper &lt; yanegomi at gmail dot com &gt;
2012-07-31 02:00:37 +00:00
if ((cpipe->pipe_state & PIPE_WANTR)) {
cpipe->pipe_state &= ~PIPE_WANTR;
merge pipe and fifo implementations Also reviewed by: jhb, jilles (initial revision) Tested by: pho, jilles Submitted by: gianni Reviewed by: bde
2012-02-23 18:37:30 +00:00
wakeup(cpipe);
When a thread is blocked in direct write state, it only sets PIPE_DIRECTW flag but not PIPE_WANTW, but FIFO pipe code does not understand this internal state, when a FIFO peer reader closes the pipe, it wants to notify the writer, it checks PIPE_WANTW, if not set, it skips calling wakeup(), so blocked writer never noticed the case, but in general, the writer should return from the syscall with EPIPE error code and may get SIGPIPE signal. Setting the PIPE_WANTW fixed problem, or you can turn off direct write, it should fix the problem too. This bug is found by PR/170203. Another bug in FIFO pipe code is when peer closes the pipe, another end which is being blocked in select() or poll() is not notified, it missed to call pipeselwakeup(). Third problem is found in poll regression test, the existing code can not pass 6b,6c,6d tests, but FreeBSD-4 works. This commit does not fix the problem, I still need to study more to find the cause. PR: 170203 Tested by: Garrett Copper &lt; yanegomi at gmail dot com &gt;
2012-07-31 02:00:37 +00:00
}
I am comparing current pipe code with the one in 8.3-STABLE r236165, I found 8.3 is a history BSD version using socket to implement FIFO pipe, it uses per-file seqcount to compare with writer generation stored in per-pipe object. The concept is after all writers are gone, the pipe enters next generation, all old readers have not closed the pipe should get the indication that the pipe is disconnected, result is they should get EPIPE, SIGPIPE or get POLLHUP in poll(). But newcomer should not know that previous writters were gone, it should treat it as a fresh session. I am trying to bring back FIFO pipe to history behavior. It is still unclear that if single EOF flag can represent SBS_CANTSENDMORE and SBS_CANTRCVMORE which socket-based version is using, but I have run the poll regression test in tool directory, output is same as the one on 8.3-STABLE now. I think the output "not ok 18 FIFO state 6b: poll result 0 expected 1. expected POLLHUP; got 0" might be bogus, because newcomer should not know that old writers were gone. I got the same behavior on Linux. Our implementation always return POLLIN for disconnected pipe even it should return POLLHUP, but I think it is not wise to remove POLLIN for compatible reason, this is our history behavior. Regression test: /usr/src/tools/regression/poll
2012-07-31 05:48:35 +00:00
cpipe->pipe_wgen++;
When a thread is blocked in direct write state, it only sets PIPE_DIRECTW flag but not PIPE_WANTW, but FIFO pipe code does not understand this internal state, when a FIFO peer reader closes the pipe, it wants to notify the writer, it checks PIPE_WANTW, if not set, it skips calling wakeup(), so blocked writer never noticed the case, but in general, the writer should return from the syscall with EPIPE error code and may get SIGPIPE signal. Setting the PIPE_WANTW fixed problem, or you can turn off direct write, it should fix the problem too. This bug is found by PR/170203. Another bug in FIFO pipe code is when peer closes the pipe, another end which is being blocked in select() or poll() is not notified, it missed to call pipeselwakeup(). Third problem is found in poll regression test, the existing code can not pass 6b,6c,6d tests, but FreeBSD-4 works. This commit does not fix the problem, I still need to study more to find the cause. PR: 170203 Tested by: Garrett Copper &lt; yanegomi at gmail dot com &gt;
2012-07-31 02:00:37 +00:00
pipeselwakeup(cpipe);
merge pipe and fifo implementations Also reviewed by: jhb, jilles (initial revision) Tested by: pho, jilles Submitted by: gianni Reviewed by: bde
2012-02-23 18:37:30 +00:00
PIPE_UNLOCK(cpipe);
Fix poll(2) and select(2) for named pipes to return "ready for read" when all writers, observed by reader, exited. Use writer generation counter for fifo, and store the snapshot of the fifo generation in the f_seqcount field of struct file, that is otherwise unused for fifos. Set FreeBSD-undocumented POLLINIGNEOF flag only when file f_seqcount is equal to fifo' fi_wgen, and revert r89376. Fix POLLINIGNEOF for sockets and pipes, and return POLLHUP for them. Note that the patch does not fix not returning POLLHUP for fifos. PR: kern/94772 Submitted by: bde (original version) Reviewed by: rwatson, jilles Approved by: re (kensmith) MFC after: 6 weeks (might be)
2009-07-07 09:43:44 +00:00
}
This is the kernel Lite/2 commit. There are some requisite userland changes, so don't expect to be able to run the kernel as-is (very well) without the appropriate Lite/2 userland changes. The system boots and can mount UFS filesystems. Untested: ext2fs, msdosfs, NFS Known problems: Incorrect Berkeley ID strings in some files. Mount_std mounts will not work until the getfsent library routine is changed. Reviewed by: various people Submitted by: Jeffery Hsu <hsu@freebsd.org>
1997-02-10 02:22:35 +00:00
}
If fifo_open() is interrupted, fifo_close() may not get called, causing a resource leak. Move the resource deallocation code from fifo_close() to a new function, fifo_cleanup(), and call fifo_cleanup() from fifo_close() and the appropriate places in fifo_open(). Tested by: Lukas Ertl Pointy hat to: truckman
2003-11-10 22:21:00 +00:00
fifo_cleanup(vp);
Fix up locking problems in fifo_open() and fifo_close(): Sleep on the vnode interlock while waiting for another caller to increment fi_readers or fi_writers. Hold the vnode interlock while incrementing fi_readers or fi_writers to prevent a wakeup from being missed. Only access fi_readers and fi_writers while holding the vnode lock. Previously fifo_close() decremented their values without holding a lock. Move resource deallocation from fifo_close() to fifo_inactive(), which allows the VOP_CLOSE() call in the error return path in fifo_open() to be removed. Fifo_open() was calling VOP_CLOSE() with the vnode lock held, in violation the current vnode locking API. Also the way fifo_close() used vrefcnt() to decide whether to deallocate resources was bogus according to comments in the vrefcnt() implementation. Reviewed by: bde
2003-06-01 06:24:32 +00:00
return (0);
BSD 4.4 Lite Kernel Sources
1994-05-24 10:09:53 +00:00
}
/*
GCC cleanup. Reviewed by: Submitted by: Obtained from:
1994-10-02 17:48:58 +00:00
* Print out internal contents of a fifo vnode.
BSD 4.4 Lite Kernel Sources
1994-05-24 10:09:53 +00:00
*/
The big 4.4BSD Lite to FreeBSD 2.0.0 (Development) patch. Reviewed by: Rodney W. Grimes Submitted by: John Dyson and David Greenman
1994-05-25 09:21:21 +00:00
int
GCC cleanup. Reviewed by: Submitted by: Obtained from:
1994-10-02 17:48:58 +00:00
fifo_printinfo(vp)
struct vnode *vp;
BSD 4.4 Lite Kernel Sources
1994-05-24 10:09:53 +00:00
{
Remove register keyword from sys/ and ANSIfy prototypes A long long time ago the register keyword told the compiler to store the corresponding variable in a CPU register, but it is not relevant for any compiler used in the FreeBSD world today. ANSIfy related prototypes while here. Reviewed by: cem, jhb Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D10193
2017-05-17 00:34:34 +00:00
struct fifoinfo *fip = vp->v_fifoinfo;
BSD 4.4 Lite Kernel Sources
1994-05-24 10:09:53 +00:00
Change fifo_printinfo to check if the vnode v_fifoinfo pointer is NULL and print a message to that effect to prevent a panic.
2007-03-02 00:10:11 +00:00
if (fip == NULL){
printf(", NULL v_fifoinfo");
return (0);
}
GCC cleanup. Reviewed by: Submitted by: Obtained from:
1994-10-02 17:48:58 +00:00
printf(", fifo with %ld readers and %ld writers",
fip->fi_readers, fip->fi_writers);
The big 4.4BSD Lite to FreeBSD 2.0.0 (Development) patch. Reviewed by: Rodney W. Grimes Submitted by: John Dyson and David Greenman
1994-05-25 09:21:21 +00:00
return (0);
BSD 4.4 Lite Kernel Sources
1994-05-24 10:09:53 +00:00
}
/*
GCC cleanup. Reviewed by: Submitted by: Obtained from:
1994-10-02 17:48:58 +00:00
* Print out the contents of a fifo vnode.
BSD 4.4 Lite Kernel Sources
1994-05-24 10:09:53 +00:00
*/
Another mega commit to staticize things.
1995-12-14 09:55:16 +00:00
static int
GCC cleanup. Reviewed by: Submitted by: Obtained from:
1994-10-02 17:48:58 +00:00
fifo_print(ap)
struct vop_print_args /* {
struct vnode *a_vp;
} */ *ap;
BSD 4.4 Lite Kernel Sources
1994-05-24 10:09:53 +00:00
{
Tweak the output of VOP_PRINT/vn_printf() some. - Align the fifo output in fifo_print() with other vn_printf() output. - Remove the leading space from lockmgr_printinfo() so its output lines up in vn_printf(). - lockmgr_printinfo() now ends with a newline, so remove an extra newline from vn_printf().
2009-02-06 20:06:48 +00:00
printf(" ");
GCC cleanup. Reviewed by: Submitted by: Obtained from:
1994-10-02 17:48:58 +00:00
fifo_printinfo(ap->a_vp);
printf("\n");
The big 4.4BSD Lite to FreeBSD 2.0.0 (Development) patch. Reviewed by: Rodney W. Grimes Submitted by: John Dyson and David Greenman
1994-05-25 09:21:21 +00:00
return (0);
BSD 4.4 Lite Kernel Sources
1994-05-24 10:09:53 +00:00
}
/*
* Fifo advisory byte-level locks.
*/
/* ARGSUSED */
vnops megacommit 1. Use the default function to access all the specfs operations. 2. Use the default function to access all the fifofs operations. 3. Use the default function to access all the ufs operations. 4. Fix VCALL usage in vfs_cache.c 5. Use VOCALL to access specfs functions in devfs_vnops.c 6. Staticize most of the spec and fifofs vnops functions. 7. Make UFS panic if it lacks bits of the underlying storage handling.
1997-10-15 13:24:07 +00:00
static int
BSD 4.4 Lite Kernel Sources
1994-05-24 10:09:53 +00:00
fifo_advlock(ap)
struct vop_advlock_args /* {
struct vnode *a_vp;
caddr_t a_id;
int a_op;
struct flock *a_fl;
int a_flags;
} */ *ap;
{
Fixed errno for unsupported advisory locks. The errno is now EINVAL fcntl() and EOPNOTSUPP for flock(). POSIX specifies the weaker EINVAL errno and the man page agrees. Not fixed: deadfs: always returns wrong EBADF devfs, msdosfs: always return sometimes-wrong EINVAL cd9660, fdesc, kernfs, portal: always return sometimes-wrong EOPNOTSUPP procfs: always returns wrong EIO mfs: panic?! nfs: fudged NetBSD uses a generic file system genfs to do return the sometimes-wrong EOPNOTSUPP more consistently :-)(. Found by: NIST-PCTS
1996-12-19 18:16:33 +00:00
return (ap->a_flags & F_FLOCK ? EOPNOTSUPP : EINVAL);
BSD 4.4 Lite Kernel Sources
1994-05-24 10:09:53 +00:00
}
Add file ops to fifofs so that we can bypass vnodes (and Giant) for the heavy-duty operations (read, write, poll/select, kqueue). Disabled for now, enable with "vfs.fifofs.fops=1" in loader.conf.
2004-11-15 14:51:44 +00:00
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