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mirror of https://git.FreeBSD.org/src.git synced 2024-12-23 11:18:54 +00:00
freebsd/sys/kern/sys_pipe.c
David Xu 5ff2bb52cc 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

1819 lines
44 KiB
C

/*-
* Copyright (c) 1996 John S. Dyson
* Copyright (c) 2012 Giovanni Trematerra
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice immediately at the beginning of the file, without modification,
* 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.
* 3. Absolutely no warranty of function or purpose is made by the author
* John S. Dyson.
* 4. Modifications may be freely made to this file if the above conditions
* are met.
*/
/*
* This file contains a high-performance replacement for the socket-based
* pipes scheme originally used in FreeBSD/4.4Lite. It does not support
* all features of sockets, but does do everything that pipes normally
* do.
*/
/*
* This code has two modes of operation, a small write mode and a large
* write mode. The small write mode acts like conventional pipes with
* a kernel buffer. If the buffer is less than PIPE_MINDIRECT, then the
* "normal" pipe buffering is done. If the buffer is between PIPE_MINDIRECT
* and PIPE_SIZE in size, the sending process pins the underlying pages in
* memory, and the receiving process copies directly from these pinned pages
* in the sending process.
*
* If the sending process receives a signal, it is possible that it will
* go away, and certainly its address space can change, because control
* is returned back to the user-mode side. In that case, the pipe code
* arranges to copy the buffer supplied by the user process, to a pageable
* kernel buffer, and the receiving process will grab the data from the
* pageable kernel buffer. Since signals don't happen all that often,
* the copy operation is normally eliminated.
*
* The constant PIPE_MINDIRECT is chosen to make sure that buffering will
* happen for small transfers so that the system will not spend all of
* its time context switching.
*
* In order to limit the resource use of pipes, two sysctls exist:
*
* kern.ipc.maxpipekva - This is a hard limit on the amount of pageable
* address space available to us in pipe_map. This value is normally
* autotuned, but may also be loader tuned.
*
* kern.ipc.pipekva - This read-only sysctl tracks the current amount of
* memory in use by pipes.
*
* Based on how large pipekva is relative to maxpipekva, the following
* will happen:
*
* 0% - 50%:
* New pipes are given 16K of memory backing, pipes may dynamically
* grow to as large as 64K where needed.
* 50% - 75%:
* New pipes are given 4K (or PAGE_SIZE) of memory backing,
* existing pipes may NOT grow.
* 75% - 100%:
* New pipes are given 4K (or PAGE_SIZE) of memory backing,
* existing pipes will be shrunk down to 4K whenever possible.
*
* Resizing may be disabled by setting kern.ipc.piperesizeallowed=0. If
* that is set, the only resize that will occur is the 0 -> SMALL_PIPE_SIZE
* resize which MUST occur for reverse-direction pipes when they are
* first used.
*
* Additional information about the current state of pipes may be obtained
* from kern.ipc.pipes, kern.ipc.pipefragretry, kern.ipc.pipeallocfail,
* and kern.ipc.piperesizefail.
*
* Locking rules: There are two locks present here: A mutex, used via
* PIPE_LOCK, and a flag, used via pipelock(). All locking is done via
* the flag, as mutexes can not persist over uiomove. The mutex
* exists only to guard access to the flag, and is not in itself a
* locking mechanism. Also note that there is only a single mutex for
* both directions of a pipe.
*
* As pipelock() may have to sleep before it can acquire the flag, it
* is important to reread all data after a call to pipelock(); everything
* in the structure may have changed.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/conf.h>
#include <sys/fcntl.h>
#include <sys/file.h>
#include <sys/filedesc.h>
#include <sys/filio.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/ttycom.h>
#include <sys/stat.h>
#include <sys/malloc.h>
#include <sys/poll.h>
#include <sys/selinfo.h>
#include <sys/signalvar.h>
#include <sys/syscallsubr.h>
#include <sys/sysctl.h>
#include <sys/sysproto.h>
#include <sys/pipe.h>
#include <sys/proc.h>
#include <sys/vnode.h>
#include <sys/uio.h>
#include <sys/event.h>
#include <security/mac/mac_framework.h>
#include <vm/vm.h>
#include <vm/vm_param.h>
#include <vm/vm_object.h>
#include <vm/vm_kern.h>
#include <vm/vm_extern.h>
#include <vm/pmap.h>
#include <vm/vm_map.h>
#include <vm/vm_page.h>
#include <vm/uma.h>
/* XXX */
int do_pipe(struct thread *td, int fildes[2], int flags);
/*
* Use this define if you want to disable *fancy* VM things. Expect an
* approx 30% decrease in transfer rate. This could be useful for
* NetBSD or OpenBSD.
*/
/* #define PIPE_NODIRECT */
#define PIPE_PEER(pipe) \
(((pipe)->pipe_state & PIPE_NAMED) ? (pipe) : ((pipe)->pipe_peer))
/*
* interfaces to the outside world
*/
static fo_rdwr_t pipe_read;
static fo_rdwr_t pipe_write;
static fo_truncate_t pipe_truncate;
static fo_ioctl_t pipe_ioctl;
static fo_poll_t pipe_poll;
static fo_kqfilter_t pipe_kqfilter;
static fo_stat_t pipe_stat;
static fo_close_t pipe_close;
static fo_chmod_t pipe_chmod;
static fo_chown_t pipe_chown;
struct fileops pipeops = {
.fo_read = pipe_read,
.fo_write = pipe_write,
.fo_truncate = pipe_truncate,
.fo_ioctl = pipe_ioctl,
.fo_poll = pipe_poll,
.fo_kqfilter = pipe_kqfilter,
.fo_stat = pipe_stat,
.fo_close = pipe_close,
.fo_chmod = pipe_chmod,
.fo_chown = pipe_chown,
.fo_flags = DFLAG_PASSABLE
};
static void filt_pipedetach(struct knote *kn);
static void filt_pipedetach_notsup(struct knote *kn);
static int filt_pipenotsup(struct knote *kn, long hint);
static int filt_piperead(struct knote *kn, long hint);
static int filt_pipewrite(struct knote *kn, long hint);
static struct filterops pipe_nfiltops = {
.f_isfd = 1,
.f_detach = filt_pipedetach_notsup,
.f_event = filt_pipenotsup
};
static struct filterops pipe_rfiltops = {
.f_isfd = 1,
.f_detach = filt_pipedetach,
.f_event = filt_piperead
};
static struct filterops pipe_wfiltops = {
.f_isfd = 1,
.f_detach = filt_pipedetach,
.f_event = filt_pipewrite
};
/*
* Default pipe buffer size(s), this can be kind-of large now because pipe
* space is pageable. The pipe code will try to maintain locality of
* reference for performance reasons, so small amounts of outstanding I/O
* will not wipe the cache.
*/
#define MINPIPESIZE (PIPE_SIZE/3)
#define MAXPIPESIZE (2*PIPE_SIZE/3)
static long amountpipekva;
static int pipefragretry;
static int pipeallocfail;
static int piperesizefail;
static int piperesizeallowed = 1;
SYSCTL_LONG(_kern_ipc, OID_AUTO, maxpipekva, CTLFLAG_RDTUN,
&maxpipekva, 0, "Pipe KVA limit");
SYSCTL_LONG(_kern_ipc, OID_AUTO, pipekva, CTLFLAG_RD,
&amountpipekva, 0, "Pipe KVA usage");
SYSCTL_INT(_kern_ipc, OID_AUTO, pipefragretry, CTLFLAG_RD,
&pipefragretry, 0, "Pipe allocation retries due to fragmentation");
SYSCTL_INT(_kern_ipc, OID_AUTO, pipeallocfail, CTLFLAG_RD,
&pipeallocfail, 0, "Pipe allocation failures");
SYSCTL_INT(_kern_ipc, OID_AUTO, piperesizefail, CTLFLAG_RD,
&piperesizefail, 0, "Pipe resize failures");
SYSCTL_INT(_kern_ipc, OID_AUTO, piperesizeallowed, CTLFLAG_RW,
&piperesizeallowed, 0, "Pipe resizing allowed");
static void pipeinit(void *dummy __unused);
static void pipeclose(struct pipe *cpipe);
static void pipe_free_kmem(struct pipe *cpipe);
static int pipe_create(struct pipe *pipe, int backing);
static int pipe_paircreate(struct thread *td, struct pipepair **p_pp);
static __inline int pipelock(struct pipe *cpipe, int catch);
static __inline void pipeunlock(struct pipe *cpipe);
#ifndef PIPE_NODIRECT
static int pipe_build_write_buffer(struct pipe *wpipe, struct uio *uio);
static void pipe_destroy_write_buffer(struct pipe *wpipe);
static int pipe_direct_write(struct pipe *wpipe, struct uio *uio);
static void pipe_clone_write_buffer(struct pipe *wpipe);
#endif
static int pipespace(struct pipe *cpipe, int size);
static int pipespace_new(struct pipe *cpipe, int size);
static int pipe_zone_ctor(void *mem, int size, void *arg, int flags);
static int pipe_zone_init(void *mem, int size, int flags);
static void pipe_zone_fini(void *mem, int size);
static uma_zone_t pipe_zone;
static struct unrhdr *pipeino_unr;
static dev_t pipedev_ino;
SYSINIT(vfs, SI_SUB_VFS, SI_ORDER_ANY, pipeinit, NULL);
static void
pipeinit(void *dummy __unused)
{
pipe_zone = uma_zcreate("pipe", sizeof(struct pipepair),
pipe_zone_ctor, NULL, pipe_zone_init, pipe_zone_fini,
UMA_ALIGN_PTR, 0);
KASSERT(pipe_zone != NULL, ("pipe_zone not initialized"));
pipeino_unr = new_unrhdr(1, INT32_MAX, NULL);
KASSERT(pipeino_unr != NULL, ("pipe fake inodes not initialized"));
pipedev_ino = devfs_alloc_cdp_inode();
KASSERT(pipedev_ino > 0, ("pipe dev inode not initialized"));
}
static int
pipe_zone_ctor(void *mem, int size, void *arg, int flags)
{
struct pipepair *pp;
struct pipe *rpipe, *wpipe;
KASSERT(size == sizeof(*pp), ("pipe_zone_ctor: wrong size"));
pp = (struct pipepair *)mem;
/*
* We zero both pipe endpoints to make sure all the kmem pointers
* are NULL, flag fields are zero'd, etc. We timestamp both
* endpoints with the same time.
*/
rpipe = &pp->pp_rpipe;
bzero(rpipe, sizeof(*rpipe));
vfs_timestamp(&rpipe->pipe_ctime);
rpipe->pipe_atime = rpipe->pipe_mtime = rpipe->pipe_ctime;
wpipe = &pp->pp_wpipe;
bzero(wpipe, sizeof(*wpipe));
wpipe->pipe_ctime = rpipe->pipe_ctime;
wpipe->pipe_atime = wpipe->pipe_mtime = rpipe->pipe_ctime;
rpipe->pipe_peer = wpipe;
rpipe->pipe_pair = pp;
wpipe->pipe_peer = rpipe;
wpipe->pipe_pair = pp;
/*
* Mark both endpoints as present; they will later get free'd
* one at a time. When both are free'd, then the whole pair
* is released.
*/
rpipe->pipe_present = PIPE_ACTIVE;
wpipe->pipe_present = PIPE_ACTIVE;
/*
* Eventually, the MAC Framework may initialize the label
* in ctor or init, but for now we do it elswhere to avoid
* blocking in ctor or init.
*/
pp->pp_label = NULL;
return (0);
}
static int
pipe_zone_init(void *mem, int size, int flags)
{
struct pipepair *pp;
KASSERT(size == sizeof(*pp), ("pipe_zone_init: wrong size"));
pp = (struct pipepair *)mem;
mtx_init(&pp->pp_mtx, "pipe mutex", NULL, MTX_DEF | MTX_RECURSE);
return (0);
}
static void
pipe_zone_fini(void *mem, int size)
{
struct pipepair *pp;
KASSERT(size == sizeof(*pp), ("pipe_zone_fini: wrong size"));
pp = (struct pipepair *)mem;
mtx_destroy(&pp->pp_mtx);
}
static int
pipe_paircreate(struct thread *td, struct pipepair **p_pp)
{
struct pipepair *pp;
struct pipe *rpipe, *wpipe;
int error;
*p_pp = pp = uma_zalloc(pipe_zone, M_WAITOK);
#ifdef MAC
/*
* The MAC label is shared between the connected endpoints. As a
* result mac_pipe_init() and mac_pipe_create() are called once
* for the pair, and not on the endpoints.
*/
mac_pipe_init(pp);
mac_pipe_create(td->td_ucred, pp);
#endif
rpipe = &pp->pp_rpipe;
wpipe = &pp->pp_wpipe;
knlist_init_mtx(&rpipe->pipe_sel.si_note, PIPE_MTX(rpipe));
knlist_init_mtx(&wpipe->pipe_sel.si_note, PIPE_MTX(wpipe));
/* Only the forward direction pipe is backed by default */
if ((error = pipe_create(rpipe, 1)) != 0 ||
(error = pipe_create(wpipe, 0)) != 0) {
pipeclose(rpipe);
pipeclose(wpipe);
return (error);
}
rpipe->pipe_state |= PIPE_DIRECTOK;
wpipe->pipe_state |= PIPE_DIRECTOK;
return (0);
}
int
pipe_named_ctor(struct pipe **ppipe, struct thread *td)
{
struct pipepair *pp;
int error;
error = pipe_paircreate(td, &pp);
if (error != 0)
return (error);
pp->pp_rpipe.pipe_state |= PIPE_NAMED;
*ppipe = &pp->pp_rpipe;
return (0);
}
void
pipe_dtor(struct pipe *dpipe)
{
ino_t ino;
ino = dpipe->pipe_ino;
funsetown(&dpipe->pipe_sigio);
pipeclose(dpipe);
if (dpipe->pipe_state & PIPE_NAMED) {
dpipe = dpipe->pipe_peer;
funsetown(&dpipe->pipe_sigio);
pipeclose(dpipe);
}
if (ino != 0 && ino != (ino_t)-1)
free_unr(pipeino_unr, ino);
}
/*
* The pipe system call for the DTYPE_PIPE type of pipes. If we fail, let
* the zone pick up the pieces via pipeclose().
*/
int
kern_pipe(struct thread *td, int fildes[2])
{
return (do_pipe(td, fildes, 0));
}
int
do_pipe(struct thread *td, int fildes[2], int flags)
{
struct filedesc *fdp;
struct file *rf, *wf;
struct pipe *rpipe, *wpipe;
struct pipepair *pp;
int fd, fflags, error;
fdp = td->td_proc->p_fd;
error = pipe_paircreate(td, &pp);
if (error != 0)
return (error);
rpipe = &pp->pp_rpipe;
wpipe = &pp->pp_wpipe;
error = falloc(td, &rf, &fd, flags);
if (error) {
pipeclose(rpipe);
pipeclose(wpipe);
return (error);
}
/* An extra reference on `rf' has been held for us by falloc(). */
fildes[0] = fd;
fflags = FREAD | FWRITE;
if ((flags & O_NONBLOCK) != 0)
fflags |= FNONBLOCK;
/*
* Warning: once we've gotten past allocation of the fd for the
* read-side, we can only drop the read side via fdrop() in order
* to avoid races against processes which manage to dup() the read
* side while we are blocked trying to allocate the write side.
*/
finit(rf, fflags, DTYPE_PIPE, rpipe, &pipeops);
error = falloc(td, &wf, &fd, flags);
if (error) {
fdclose(fdp, rf, fildes[0], td);
fdrop(rf, td);
/* rpipe has been closed by fdrop(). */
pipeclose(wpipe);
return (error);
}
/* An extra reference on `wf' has been held for us by falloc(). */
finit(wf, fflags, DTYPE_PIPE, wpipe, &pipeops);
fdrop(wf, td);
fildes[1] = fd;
fdrop(rf, td);
return (0);
}
/* ARGSUSED */
int
sys_pipe(struct thread *td, struct pipe_args *uap)
{
int error;
int fildes[2];
error = kern_pipe(td, fildes);
if (error)
return (error);
td->td_retval[0] = fildes[0];
td->td_retval[1] = fildes[1];
return (0);
}
/*
* Allocate kva for pipe circular buffer, the space is pageable
* This routine will 'realloc' the size of a pipe safely, if it fails
* it will retain the old buffer.
* If it fails it will return ENOMEM.
*/
static int
pipespace_new(cpipe, size)
struct pipe *cpipe;
int size;
{
caddr_t buffer;
int error, cnt, firstseg;
static int curfail = 0;
static struct timeval lastfail;
KASSERT(!mtx_owned(PIPE_MTX(cpipe)), ("pipespace: pipe mutex locked"));
KASSERT(!(cpipe->pipe_state & PIPE_DIRECTW),
("pipespace: resize of direct writes not allowed"));
retry:
cnt = cpipe->pipe_buffer.cnt;
if (cnt > size)
size = cnt;
size = round_page(size);
buffer = (caddr_t) vm_map_min(pipe_map);
error = vm_map_find(pipe_map, NULL, 0,
(vm_offset_t *) &buffer, size, 1,
VM_PROT_ALL, VM_PROT_ALL, 0);
if (error != KERN_SUCCESS) {
if ((cpipe->pipe_buffer.buffer == NULL) &&
(size > SMALL_PIPE_SIZE)) {
size = SMALL_PIPE_SIZE;
pipefragretry++;
goto retry;
}
if (cpipe->pipe_buffer.buffer == NULL) {
pipeallocfail++;
if (ppsratecheck(&lastfail, &curfail, 1))
printf("kern.ipc.maxpipekva exceeded; see tuning(7)\n");
} else {
piperesizefail++;
}
return (ENOMEM);
}
/* copy data, then free old resources if we're resizing */
if (cnt > 0) {
if (cpipe->pipe_buffer.in <= cpipe->pipe_buffer.out) {
firstseg = cpipe->pipe_buffer.size - cpipe->pipe_buffer.out;
bcopy(&cpipe->pipe_buffer.buffer[cpipe->pipe_buffer.out],
buffer, firstseg);
if ((cnt - firstseg) > 0)
bcopy(cpipe->pipe_buffer.buffer, &buffer[firstseg],
cpipe->pipe_buffer.in);
} else {
bcopy(&cpipe->pipe_buffer.buffer[cpipe->pipe_buffer.out],
buffer, cnt);
}
}
pipe_free_kmem(cpipe);
cpipe->pipe_buffer.buffer = buffer;
cpipe->pipe_buffer.size = size;
cpipe->pipe_buffer.in = cnt;
cpipe->pipe_buffer.out = 0;
cpipe->pipe_buffer.cnt = cnt;
atomic_add_long(&amountpipekva, cpipe->pipe_buffer.size);
return (0);
}
/*
* Wrapper for pipespace_new() that performs locking assertions.
*/
static int
pipespace(cpipe, size)
struct pipe *cpipe;
int size;
{
KASSERT(cpipe->pipe_state & PIPE_LOCKFL,
("Unlocked pipe passed to pipespace"));
return (pipespace_new(cpipe, size));
}
/*
* lock a pipe for I/O, blocking other access
*/
static __inline int
pipelock(cpipe, catch)
struct pipe *cpipe;
int catch;
{
int error;
PIPE_LOCK_ASSERT(cpipe, MA_OWNED);
while (cpipe->pipe_state & PIPE_LOCKFL) {
cpipe->pipe_state |= PIPE_LWANT;
error = msleep(cpipe, PIPE_MTX(cpipe),
catch ? (PRIBIO | PCATCH) : PRIBIO,
"pipelk", 0);
if (error != 0)
return (error);
}
cpipe->pipe_state |= PIPE_LOCKFL;
return (0);
}
/*
* unlock a pipe I/O lock
*/
static __inline void
pipeunlock(cpipe)
struct pipe *cpipe;
{
PIPE_LOCK_ASSERT(cpipe, MA_OWNED);
KASSERT(cpipe->pipe_state & PIPE_LOCKFL,
("Unlocked pipe passed to pipeunlock"));
cpipe->pipe_state &= ~PIPE_LOCKFL;
if (cpipe->pipe_state & PIPE_LWANT) {
cpipe->pipe_state &= ~PIPE_LWANT;
wakeup(cpipe);
}
}
void
pipeselwakeup(cpipe)
struct pipe *cpipe;
{
PIPE_LOCK_ASSERT(cpipe, MA_OWNED);
if (cpipe->pipe_state & PIPE_SEL) {
selwakeuppri(&cpipe->pipe_sel, PSOCK);
if (!SEL_WAITING(&cpipe->pipe_sel))
cpipe->pipe_state &= ~PIPE_SEL;
}
if ((cpipe->pipe_state & PIPE_ASYNC) && cpipe->pipe_sigio)
pgsigio(&cpipe->pipe_sigio, SIGIO, 0);
KNOTE_LOCKED(&cpipe->pipe_sel.si_note, 0);
}
/*
* Initialize and allocate VM and memory for pipe. The structure
* will start out zero'd from the ctor, so we just manage the kmem.
*/
static int
pipe_create(pipe, backing)
struct pipe *pipe;
int backing;
{
int error;
if (backing) {
if (amountpipekva > maxpipekva / 2)
error = pipespace_new(pipe, SMALL_PIPE_SIZE);
else
error = pipespace_new(pipe, PIPE_SIZE);
} else {
/* If we're not backing this pipe, no need to do anything. */
error = 0;
}
pipe->pipe_ino = -1;
return (error);
}
/* ARGSUSED */
static int
pipe_read(fp, uio, active_cred, flags, td)
struct file *fp;
struct uio *uio;
struct ucred *active_cred;
struct thread *td;
int flags;
{
struct pipe *rpipe;
int error;
int nread = 0;
int size;
rpipe = fp->f_data;
PIPE_LOCK(rpipe);
++rpipe->pipe_busy;
error = pipelock(rpipe, 1);
if (error)
goto unlocked_error;
#ifdef MAC
error = mac_pipe_check_read(active_cred, rpipe->pipe_pair);
if (error)
goto locked_error;
#endif
if (amountpipekva > (3 * maxpipekva) / 4) {
if (!(rpipe->pipe_state & PIPE_DIRECTW) &&
(rpipe->pipe_buffer.size > SMALL_PIPE_SIZE) &&
(rpipe->pipe_buffer.cnt <= SMALL_PIPE_SIZE) &&
(piperesizeallowed == 1)) {
PIPE_UNLOCK(rpipe);
pipespace(rpipe, SMALL_PIPE_SIZE);
PIPE_LOCK(rpipe);
}
}
while (uio->uio_resid) {
/*
* normal pipe buffer receive
*/
if (rpipe->pipe_buffer.cnt > 0) {
size = rpipe->pipe_buffer.size - rpipe->pipe_buffer.out;
if (size > rpipe->pipe_buffer.cnt)
size = rpipe->pipe_buffer.cnt;
if (size > uio->uio_resid)
size = uio->uio_resid;
PIPE_UNLOCK(rpipe);
error = uiomove(
&rpipe->pipe_buffer.buffer[rpipe->pipe_buffer.out],
size, uio);
PIPE_LOCK(rpipe);
if (error)
break;
rpipe->pipe_buffer.out += size;
if (rpipe->pipe_buffer.out >= rpipe->pipe_buffer.size)
rpipe->pipe_buffer.out = 0;
rpipe->pipe_buffer.cnt -= size;
/*
* If there is no more to read in the pipe, reset
* its pointers to the beginning. This improves
* cache hit stats.
*/
if (rpipe->pipe_buffer.cnt == 0) {
rpipe->pipe_buffer.in = 0;
rpipe->pipe_buffer.out = 0;
}
nread += size;
#ifndef PIPE_NODIRECT
/*
* Direct copy, bypassing a kernel buffer.
*/
} else if ((size = rpipe->pipe_map.cnt) &&
(rpipe->pipe_state & PIPE_DIRECTW)) {
if (size > uio->uio_resid)
size = (u_int) uio->uio_resid;
PIPE_UNLOCK(rpipe);
error = uiomove_fromphys(rpipe->pipe_map.ms,
rpipe->pipe_map.pos, size, uio);
PIPE_LOCK(rpipe);
if (error)
break;
nread += size;
rpipe->pipe_map.pos += size;
rpipe->pipe_map.cnt -= size;
if (rpipe->pipe_map.cnt == 0) {
rpipe->pipe_state &= ~(PIPE_DIRECTW|PIPE_WANTW);
wakeup(rpipe);
}
#endif
} else {
/*
* detect EOF condition
* read returns 0 on EOF, no need to set error
*/
if (rpipe->pipe_state & PIPE_EOF)
break;
/*
* If the "write-side" has been blocked, wake it up now.
*/
if (rpipe->pipe_state & PIPE_WANTW) {
rpipe->pipe_state &= ~PIPE_WANTW;
wakeup(rpipe);
}
/*
* Break if some data was read.
*/
if (nread > 0)
break;
/*
* Unlock the pipe buffer for our remaining processing.
* We will either break out with an error or we will
* sleep and relock to loop.
*/
pipeunlock(rpipe);
/*
* Handle non-blocking mode operation or
* wait for more data.
*/
if (fp->f_flag & FNONBLOCK) {
error = EAGAIN;
} else {
rpipe->pipe_state |= PIPE_WANTR;
if ((error = msleep(rpipe, PIPE_MTX(rpipe),
PRIBIO | PCATCH,
"piperd", 0)) == 0)
error = pipelock(rpipe, 1);
}
if (error)
goto unlocked_error;
}
}
#ifdef MAC
locked_error:
#endif
pipeunlock(rpipe);
/* XXX: should probably do this before getting any locks. */
if (error == 0)
vfs_timestamp(&rpipe->pipe_atime);
unlocked_error:
--rpipe->pipe_busy;
/*
* PIPE_WANT processing only makes sense if pipe_busy is 0.
*/
if ((rpipe->pipe_busy == 0) && (rpipe->pipe_state & PIPE_WANT)) {
rpipe->pipe_state &= ~(PIPE_WANT|PIPE_WANTW);
wakeup(rpipe);
} else if (rpipe->pipe_buffer.cnt < MINPIPESIZE) {
/*
* Handle write blocking hysteresis.
*/
if (rpipe->pipe_state & PIPE_WANTW) {
rpipe->pipe_state &= ~PIPE_WANTW;
wakeup(rpipe);
}
}
if ((rpipe->pipe_buffer.size - rpipe->pipe_buffer.cnt) >= PIPE_BUF)
pipeselwakeup(rpipe);
PIPE_UNLOCK(rpipe);
return (error);
}
#ifndef PIPE_NODIRECT
/*
* Map the sending processes' buffer into kernel space and wire it.
* This is similar to a physical write operation.
*/
static int
pipe_build_write_buffer(wpipe, uio)
struct pipe *wpipe;
struct uio *uio;
{
u_int size;
int i;
PIPE_LOCK_ASSERT(wpipe, MA_NOTOWNED);
KASSERT(wpipe->pipe_state & PIPE_DIRECTW,
("Clone attempt on non-direct write pipe!"));
if (uio->uio_iov->iov_len > wpipe->pipe_buffer.size)
size = wpipe->pipe_buffer.size;
else
size = uio->uio_iov->iov_len;
if ((i = vm_fault_quick_hold_pages(&curproc->p_vmspace->vm_map,
(vm_offset_t)uio->uio_iov->iov_base, size, VM_PROT_READ,
wpipe->pipe_map.ms, PIPENPAGES)) < 0)
return (EFAULT);
/*
* set up the control block
*/
wpipe->pipe_map.npages = i;
wpipe->pipe_map.pos =
((vm_offset_t) uio->uio_iov->iov_base) & PAGE_MASK;
wpipe->pipe_map.cnt = size;
/*
* and update the uio data
*/
uio->uio_iov->iov_len -= size;
uio->uio_iov->iov_base = (char *)uio->uio_iov->iov_base + size;
if (uio->uio_iov->iov_len == 0)
uio->uio_iov++;
uio->uio_resid -= size;
uio->uio_offset += size;
return (0);
}
/*
* unmap and unwire the process buffer
*/
static void
pipe_destroy_write_buffer(wpipe)
struct pipe *wpipe;
{
PIPE_LOCK_ASSERT(wpipe, MA_OWNED);
vm_page_unhold_pages(wpipe->pipe_map.ms, wpipe->pipe_map.npages);
wpipe->pipe_map.npages = 0;
}
/*
* In the case of a signal, the writing process might go away. This
* code copies the data into the circular buffer so that the source
* pages can be freed without loss of data.
*/
static void
pipe_clone_write_buffer(wpipe)
struct pipe *wpipe;
{
struct uio uio;
struct iovec iov;
int size;
int pos;
PIPE_LOCK_ASSERT(wpipe, MA_OWNED);
size = wpipe->pipe_map.cnt;
pos = wpipe->pipe_map.pos;
wpipe->pipe_buffer.in = size;
wpipe->pipe_buffer.out = 0;
wpipe->pipe_buffer.cnt = size;
wpipe->pipe_state &= ~PIPE_DIRECTW;
PIPE_UNLOCK(wpipe);
iov.iov_base = wpipe->pipe_buffer.buffer;
iov.iov_len = size;
uio.uio_iov = &iov;
uio.uio_iovcnt = 1;
uio.uio_offset = 0;
uio.uio_resid = size;
uio.uio_segflg = UIO_SYSSPACE;
uio.uio_rw = UIO_READ;
uio.uio_td = curthread;
uiomove_fromphys(wpipe->pipe_map.ms, pos, size, &uio);
PIPE_LOCK(wpipe);
pipe_destroy_write_buffer(wpipe);
}
/*
* This implements the pipe buffer write mechanism. Note that only
* a direct write OR a normal pipe write can be pending at any given time.
* If there are any characters in the pipe buffer, the direct write will
* be deferred until the receiving process grabs all of the bytes from
* the pipe buffer. Then the direct mapping write is set-up.
*/
static int
pipe_direct_write(wpipe, uio)
struct pipe *wpipe;
struct uio *uio;
{
int error;
retry:
PIPE_LOCK_ASSERT(wpipe, MA_OWNED);
error = pipelock(wpipe, 1);
if (wpipe->pipe_state & PIPE_EOF)
error = EPIPE;
if (error) {
pipeunlock(wpipe);
goto error1;
}
while (wpipe->pipe_state & PIPE_DIRECTW) {
if (wpipe->pipe_state & PIPE_WANTR) {
wpipe->pipe_state &= ~PIPE_WANTR;
wakeup(wpipe);
}
pipeselwakeup(wpipe);
wpipe->pipe_state |= PIPE_WANTW;
pipeunlock(wpipe);
error = msleep(wpipe, PIPE_MTX(wpipe),
PRIBIO | PCATCH, "pipdww", 0);
if (error)
goto error1;
else
goto retry;
}
wpipe->pipe_map.cnt = 0; /* transfer not ready yet */
if (wpipe->pipe_buffer.cnt > 0) {
if (wpipe->pipe_state & PIPE_WANTR) {
wpipe->pipe_state &= ~PIPE_WANTR;
wakeup(wpipe);
}
pipeselwakeup(wpipe);
wpipe->pipe_state |= PIPE_WANTW;
pipeunlock(wpipe);
error = msleep(wpipe, PIPE_MTX(wpipe),
PRIBIO | PCATCH, "pipdwc", 0);
if (error)
goto error1;
else
goto retry;
}
wpipe->pipe_state |= PIPE_DIRECTW;
PIPE_UNLOCK(wpipe);
error = pipe_build_write_buffer(wpipe, uio);
PIPE_LOCK(wpipe);
if (error) {
wpipe->pipe_state &= ~PIPE_DIRECTW;
pipeunlock(wpipe);
goto error1;
}
error = 0;
while (!error && (wpipe->pipe_state & PIPE_DIRECTW)) {
if (wpipe->pipe_state & PIPE_EOF) {
pipe_destroy_write_buffer(wpipe);
pipeselwakeup(wpipe);
pipeunlock(wpipe);
error = EPIPE;
goto error1;
}
if (wpipe->pipe_state & PIPE_WANTR) {
wpipe->pipe_state &= ~PIPE_WANTR;
wakeup(wpipe);
}
pipeselwakeup(wpipe);
wpipe->pipe_state |= PIPE_WANTW;
pipeunlock(wpipe);
error = msleep(wpipe, PIPE_MTX(wpipe), PRIBIO | PCATCH,
"pipdwt", 0);
pipelock(wpipe, 0);
}
if (wpipe->pipe_state & PIPE_EOF)
error = EPIPE;
if (wpipe->pipe_state & PIPE_DIRECTW) {
/*
* this bit of trickery substitutes a kernel buffer for
* the process that might be going away.
*/
pipe_clone_write_buffer(wpipe);
} else {
pipe_destroy_write_buffer(wpipe);
}
pipeunlock(wpipe);
return (error);
error1:
wakeup(wpipe);
return (error);
}
#endif
static int
pipe_write(fp, uio, active_cred, flags, td)
struct file *fp;
struct uio *uio;
struct ucred *active_cred;
struct thread *td;
int flags;
{
int error = 0;
int desiredsize;
ssize_t orig_resid;
struct pipe *wpipe, *rpipe;
rpipe = fp->f_data;
wpipe = PIPE_PEER(rpipe);
PIPE_LOCK(rpipe);
error = pipelock(wpipe, 1);
if (error) {
PIPE_UNLOCK(rpipe);
return (error);
}
/*
* detect loss of pipe read side, issue SIGPIPE if lost.
*/
if (wpipe->pipe_present != PIPE_ACTIVE ||
(wpipe->pipe_state & PIPE_EOF)) {
pipeunlock(wpipe);
PIPE_UNLOCK(rpipe);
return (EPIPE);
}
#ifdef MAC
error = mac_pipe_check_write(active_cred, wpipe->pipe_pair);
if (error) {
pipeunlock(wpipe);
PIPE_UNLOCK(rpipe);
return (error);
}
#endif
++wpipe->pipe_busy;
/* Choose a larger size if it's advantageous */
desiredsize = max(SMALL_PIPE_SIZE, wpipe->pipe_buffer.size);
while (desiredsize < wpipe->pipe_buffer.cnt + uio->uio_resid) {
if (piperesizeallowed != 1)
break;
if (amountpipekva > maxpipekva / 2)
break;
if (desiredsize == BIG_PIPE_SIZE)
break;
desiredsize = desiredsize * 2;
}
/* Choose a smaller size if we're in a OOM situation */
if ((amountpipekva > (3 * maxpipekva) / 4) &&
(wpipe->pipe_buffer.size > SMALL_PIPE_SIZE) &&
(wpipe->pipe_buffer.cnt <= SMALL_PIPE_SIZE) &&
(piperesizeallowed == 1))
desiredsize = SMALL_PIPE_SIZE;
/* Resize if the above determined that a new size was necessary */
if ((desiredsize != wpipe->pipe_buffer.size) &&
((wpipe->pipe_state & PIPE_DIRECTW) == 0)) {
PIPE_UNLOCK(wpipe);
pipespace(wpipe, desiredsize);
PIPE_LOCK(wpipe);
}
if (wpipe->pipe_buffer.size == 0) {
/*
* This can only happen for reverse direction use of pipes
* in a complete OOM situation.
*/
error = ENOMEM;
--wpipe->pipe_busy;
pipeunlock(wpipe);
PIPE_UNLOCK(wpipe);
return (error);
}
pipeunlock(wpipe);
orig_resid = uio->uio_resid;
while (uio->uio_resid) {
int space;
pipelock(wpipe, 0);
if (wpipe->pipe_state & PIPE_EOF) {
pipeunlock(wpipe);
error = EPIPE;
break;
}
#ifndef PIPE_NODIRECT
/*
* If the transfer is large, we can gain performance if
* we do process-to-process copies directly.
* If the write is non-blocking, we don't use the
* direct write mechanism.
*
* The direct write mechanism will detect the reader going
* away on us.
*/
if (uio->uio_segflg == UIO_USERSPACE &&
uio->uio_iov->iov_len >= PIPE_MINDIRECT &&
wpipe->pipe_buffer.size >= PIPE_MINDIRECT &&
(fp->f_flag & FNONBLOCK) == 0) {
pipeunlock(wpipe);
error = pipe_direct_write(wpipe, uio);
if (error)
break;
continue;
}
#endif
/*
* Pipe buffered writes cannot be coincidental with
* direct writes. We wait until the currently executing
* direct write is completed before we start filling the
* pipe buffer. We break out if a signal occurs or the
* reader goes away.
*/
if (wpipe->pipe_state & PIPE_DIRECTW) {
if (wpipe->pipe_state & PIPE_WANTR) {
wpipe->pipe_state &= ~PIPE_WANTR;
wakeup(wpipe);
}
pipeselwakeup(wpipe);
wpipe->pipe_state |= PIPE_WANTW;
pipeunlock(wpipe);
error = msleep(wpipe, PIPE_MTX(rpipe), PRIBIO | PCATCH,
"pipbww", 0);
if (error)
break;
else
continue;
}
space = wpipe->pipe_buffer.size - wpipe->pipe_buffer.cnt;
/* Writes of size <= PIPE_BUF must be atomic. */
if ((space < uio->uio_resid) && (orig_resid <= PIPE_BUF))
space = 0;
if (space > 0) {
int size; /* Transfer size */
int segsize; /* first segment to transfer */
/*
* Transfer size is minimum of uio transfer
* and free space in pipe buffer.
*/
if (space > uio->uio_resid)
size = uio->uio_resid;
else
size = space;
/*
* First segment to transfer is minimum of
* transfer size and contiguous space in
* pipe buffer. If first segment to transfer
* is less than the transfer size, we've got
* a wraparound in the buffer.
*/
segsize = wpipe->pipe_buffer.size -
wpipe->pipe_buffer.in;
if (segsize > size)
segsize = size;
/* Transfer first segment */
PIPE_UNLOCK(rpipe);
error = uiomove(&wpipe->pipe_buffer.buffer[wpipe->pipe_buffer.in],
segsize, uio);
PIPE_LOCK(rpipe);
if (error == 0 && segsize < size) {
KASSERT(wpipe->pipe_buffer.in + segsize ==
wpipe->pipe_buffer.size,
("Pipe buffer wraparound disappeared"));
/*
* Transfer remaining part now, to
* support atomic writes. Wraparound
* happened.
*/
PIPE_UNLOCK(rpipe);
error = uiomove(
&wpipe->pipe_buffer.buffer[0],
size - segsize, uio);
PIPE_LOCK(rpipe);
}
if (error == 0) {
wpipe->pipe_buffer.in += size;
if (wpipe->pipe_buffer.in >=
wpipe->pipe_buffer.size) {
KASSERT(wpipe->pipe_buffer.in ==
size - segsize +
wpipe->pipe_buffer.size,
("Expected wraparound bad"));
wpipe->pipe_buffer.in = size - segsize;
}
wpipe->pipe_buffer.cnt += size;
KASSERT(wpipe->pipe_buffer.cnt <=
wpipe->pipe_buffer.size,
("Pipe buffer overflow"));
}
pipeunlock(wpipe);
if (error != 0)
break;
} else {
/*
* If the "read-side" has been blocked, wake it up now.
*/
if (wpipe->pipe_state & PIPE_WANTR) {
wpipe->pipe_state &= ~PIPE_WANTR;
wakeup(wpipe);
}
/*
* don't block on non-blocking I/O
*/
if (fp->f_flag & FNONBLOCK) {
error = EAGAIN;
pipeunlock(wpipe);
break;
}
/*
* We have no more space and have something to offer,
* wake up select/poll.
*/
pipeselwakeup(wpipe);
wpipe->pipe_state |= PIPE_WANTW;
pipeunlock(wpipe);
error = msleep(wpipe, PIPE_MTX(rpipe),
PRIBIO | PCATCH, "pipewr", 0);
if (error != 0)
break;
}
}
pipelock(wpipe, 0);
--wpipe->pipe_busy;
if ((wpipe->pipe_busy == 0) && (wpipe->pipe_state & PIPE_WANT)) {
wpipe->pipe_state &= ~(PIPE_WANT | PIPE_WANTR);
wakeup(wpipe);
} else if (wpipe->pipe_buffer.cnt > 0) {
/*
* If we have put any characters in the buffer, we wake up
* the reader.
*/
if (wpipe->pipe_state & PIPE_WANTR) {
wpipe->pipe_state &= ~PIPE_WANTR;
wakeup(wpipe);
}
}
/*
* Don't return EPIPE if I/O was successful
*/
if ((wpipe->pipe_buffer.cnt == 0) &&
(uio->uio_resid == 0) &&
(error == EPIPE)) {
error = 0;
}
if (error == 0)
vfs_timestamp(&wpipe->pipe_mtime);
/*
* We have something to offer,
* wake up select/poll.
*/
if (wpipe->pipe_buffer.cnt)
pipeselwakeup(wpipe);
pipeunlock(wpipe);
PIPE_UNLOCK(rpipe);
return (error);
}
/* ARGSUSED */
static int
pipe_truncate(fp, length, active_cred, td)
struct file *fp;
off_t length;
struct ucred *active_cred;
struct thread *td;
{
/* For named pipes call the vnode operation. */
if (fp->f_vnode != NULL)
return (vnops.fo_truncate(fp, length, active_cred, td));
return (EINVAL);
}
/*
* we implement a very minimal set of ioctls for compatibility with sockets.
*/
static int
pipe_ioctl(fp, cmd, data, active_cred, td)
struct file *fp;
u_long cmd;
void *data;
struct ucred *active_cred;
struct thread *td;
{
struct pipe *mpipe = fp->f_data;
int error;
PIPE_LOCK(mpipe);
#ifdef MAC
error = mac_pipe_check_ioctl(active_cred, mpipe->pipe_pair, cmd, data);
if (error) {
PIPE_UNLOCK(mpipe);
return (error);
}
#endif
error = 0;
switch (cmd) {
case FIONBIO:
break;
case FIOASYNC:
if (*(int *)data) {
mpipe->pipe_state |= PIPE_ASYNC;
} else {
mpipe->pipe_state &= ~PIPE_ASYNC;
}
break;
case FIONREAD:
if (!(fp->f_flag & FREAD)) {
*(int *)data = 0;
PIPE_UNLOCK(mpipe);
return (0);
}
if (mpipe->pipe_state & PIPE_DIRECTW)
*(int *)data = mpipe->pipe_map.cnt;
else
*(int *)data = mpipe->pipe_buffer.cnt;
break;
case FIOSETOWN:
PIPE_UNLOCK(mpipe);
error = fsetown(*(int *)data, &mpipe->pipe_sigio);
goto out_unlocked;
case FIOGETOWN:
*(int *)data = fgetown(&mpipe->pipe_sigio);
break;
/* This is deprecated, FIOSETOWN should be used instead. */
case TIOCSPGRP:
PIPE_UNLOCK(mpipe);
error = fsetown(-(*(int *)data), &mpipe->pipe_sigio);
goto out_unlocked;
/* This is deprecated, FIOGETOWN should be used instead. */
case TIOCGPGRP:
*(int *)data = -fgetown(&mpipe->pipe_sigio);
break;
default:
error = ENOTTY;
break;
}
PIPE_UNLOCK(mpipe);
out_unlocked:
return (error);
}
static int
pipe_poll(fp, events, active_cred, td)
struct file *fp;
int events;
struct ucred *active_cred;
struct thread *td;
{
struct pipe *rpipe;
struct pipe *wpipe;
int levents, revents;
#ifdef MAC
int error;
#endif
revents = 0;
rpipe = fp->f_data;
wpipe = PIPE_PEER(rpipe);
PIPE_LOCK(rpipe);
#ifdef MAC
error = mac_pipe_check_poll(active_cred, rpipe->pipe_pair);
if (error)
goto locked_error;
#endif
if (fp->f_flag & FREAD && events & (POLLIN | POLLRDNORM))
if ((rpipe->pipe_state & PIPE_DIRECTW) ||
(rpipe->pipe_buffer.cnt > 0))
revents |= events & (POLLIN | POLLRDNORM);
if (fp->f_flag & FWRITE && events & (POLLOUT | POLLWRNORM))
if (wpipe->pipe_present != PIPE_ACTIVE ||
(wpipe->pipe_state & PIPE_EOF) ||
(((wpipe->pipe_state & PIPE_DIRECTW) == 0) &&
((wpipe->pipe_buffer.size - wpipe->pipe_buffer.cnt) >= PIPE_BUF ||
wpipe->pipe_buffer.size == 0)))
revents |= events & (POLLOUT | POLLWRNORM);
levents = events &
(POLLIN | POLLINIGNEOF | POLLPRI | POLLRDNORM | POLLRDBAND);
if (rpipe->pipe_state & PIPE_NAMED && fp->f_flag & FREAD && levents &&
fp->f_seqcount == rpipe->pipe_wgen)
events |= POLLINIGNEOF;
if ((events & POLLINIGNEOF) == 0) {
if (rpipe->pipe_state & PIPE_EOF) {
revents |= (events & (POLLIN | POLLRDNORM));
if (wpipe->pipe_present != PIPE_ACTIVE ||
(wpipe->pipe_state & PIPE_EOF))
revents |= POLLHUP;
}
}
if (revents == 0) {
if (fp->f_flag & FREAD && events & (POLLIN | POLLRDNORM)) {
selrecord(td, &rpipe->pipe_sel);
if (SEL_WAITING(&rpipe->pipe_sel))
rpipe->pipe_state |= PIPE_SEL;
}
if (fp->f_flag & FWRITE && events & (POLLOUT | POLLWRNORM)) {
selrecord(td, &wpipe->pipe_sel);
if (SEL_WAITING(&wpipe->pipe_sel))
wpipe->pipe_state |= PIPE_SEL;
}
}
#ifdef MAC
locked_error:
#endif
PIPE_UNLOCK(rpipe);
return (revents);
}
/*
* We shouldn't need locks here as we're doing a read and this should
* be a natural race.
*/
static int
pipe_stat(fp, ub, active_cred, td)
struct file *fp;
struct stat *ub;
struct ucred *active_cred;
struct thread *td;
{
struct pipe *pipe;
int new_unr;
#ifdef MAC
int error;
#endif
pipe = fp->f_data;
PIPE_LOCK(pipe);
#ifdef MAC
error = mac_pipe_check_stat(active_cred, pipe->pipe_pair);
if (error) {
PIPE_UNLOCK(pipe);
return (error);
}
#endif
/* For named pipes ask the underlying filesystem. */
if (pipe->pipe_state & PIPE_NAMED) {
PIPE_UNLOCK(pipe);
return (vnops.fo_stat(fp, ub, active_cred, td));
}
/*
* Lazily allocate an inode number for the pipe. Most pipe
* users do not call fstat(2) on the pipe, which means that
* postponing the inode allocation until it is must be
* returned to userland is useful. If alloc_unr failed,
* assign st_ino zero instead of returning an error.
* Special pipe_ino values:
* -1 - not yet initialized;
* 0 - alloc_unr failed, return 0 as st_ino forever.
*/
if (pipe->pipe_ino == (ino_t)-1) {
new_unr = alloc_unr(pipeino_unr);
if (new_unr != -1)
pipe->pipe_ino = new_unr;
else
pipe->pipe_ino = 0;
}
PIPE_UNLOCK(pipe);
bzero(ub, sizeof(*ub));
ub->st_mode = S_IFIFO;
ub->st_blksize = PAGE_SIZE;
if (pipe->pipe_state & PIPE_DIRECTW)
ub->st_size = pipe->pipe_map.cnt;
else
ub->st_size = pipe->pipe_buffer.cnt;
ub->st_blocks = (ub->st_size + ub->st_blksize - 1) / ub->st_blksize;
ub->st_atim = pipe->pipe_atime;
ub->st_mtim = pipe->pipe_mtime;
ub->st_ctim = pipe->pipe_ctime;
ub->st_uid = fp->f_cred->cr_uid;
ub->st_gid = fp->f_cred->cr_gid;
ub->st_dev = pipedev_ino;
ub->st_ino = pipe->pipe_ino;
/*
* Left as 0: st_nlink, st_rdev, st_flags, st_gen.
*/
return (0);
}
/* ARGSUSED */
static int
pipe_close(fp, td)
struct file *fp;
struct thread *td;
{
if (fp->f_vnode != NULL)
return vnops.fo_close(fp, td);
fp->f_ops = &badfileops;
pipe_dtor(fp->f_data);
fp->f_data = NULL;
return (0);
}
static int
pipe_chmod(struct file *fp, mode_t mode, struct ucred *active_cred, struct thread *td)
{
struct pipe *cpipe;
int error;
cpipe = fp->f_data;
if (cpipe->pipe_state & PIPE_NAMED)
error = vn_chmod(fp, mode, active_cred, td);
else
error = invfo_chmod(fp, mode, active_cred, td);
return (error);
}
static int
pipe_chown(fp, uid, gid, active_cred, td)
struct file *fp;
uid_t uid;
gid_t gid;
struct ucred *active_cred;
struct thread *td;
{
struct pipe *cpipe;
int error;
cpipe = fp->f_data;
if (cpipe->pipe_state & PIPE_NAMED)
error = vn_chown(fp, uid, gid, active_cred, td);
else
error = invfo_chown(fp, uid, gid, active_cred, td);
return (error);
}
static void
pipe_free_kmem(cpipe)
struct pipe *cpipe;
{
KASSERT(!mtx_owned(PIPE_MTX(cpipe)),
("pipe_free_kmem: pipe mutex locked"));
if (cpipe->pipe_buffer.buffer != NULL) {
atomic_subtract_long(&amountpipekva, cpipe->pipe_buffer.size);
vm_map_remove(pipe_map,
(vm_offset_t)cpipe->pipe_buffer.buffer,
(vm_offset_t)cpipe->pipe_buffer.buffer + cpipe->pipe_buffer.size);
cpipe->pipe_buffer.buffer = NULL;
}
#ifndef PIPE_NODIRECT
{
cpipe->pipe_map.cnt = 0;
cpipe->pipe_map.pos = 0;
cpipe->pipe_map.npages = 0;
}
#endif
}
/*
* shutdown the pipe
*/
static void
pipeclose(cpipe)
struct pipe *cpipe;
{
struct pipepair *pp;
struct pipe *ppipe;
KASSERT(cpipe != NULL, ("pipeclose: cpipe == NULL"));
PIPE_LOCK(cpipe);
pipelock(cpipe, 0);
pp = cpipe->pipe_pair;
pipeselwakeup(cpipe);
/*
* If the other side is blocked, wake it up saying that
* we want to close it down.
*/
cpipe->pipe_state |= PIPE_EOF;
while (cpipe->pipe_busy) {
wakeup(cpipe);
cpipe->pipe_state |= PIPE_WANT;
pipeunlock(cpipe);
msleep(cpipe, PIPE_MTX(cpipe), PRIBIO, "pipecl", 0);
pipelock(cpipe, 0);
}
/*
* Disconnect from peer, if any.
*/
ppipe = cpipe->pipe_peer;
if (ppipe->pipe_present == PIPE_ACTIVE) {
pipeselwakeup(ppipe);
ppipe->pipe_state |= PIPE_EOF;
wakeup(ppipe);
KNOTE_LOCKED(&ppipe->pipe_sel.si_note, 0);
}
/*
* Mark this endpoint as free. Release kmem resources. We
* don't mark this endpoint as unused until we've finished
* doing that, or the pipe might disappear out from under
* us.
*/
PIPE_UNLOCK(cpipe);
pipe_free_kmem(cpipe);
PIPE_LOCK(cpipe);
cpipe->pipe_present = PIPE_CLOSING;
pipeunlock(cpipe);
/*
* knlist_clear() may sleep dropping the PIPE_MTX. Set the
* PIPE_FINALIZED, that allows other end to free the
* pipe_pair, only after the knotes are completely dismantled.
*/
knlist_clear(&cpipe->pipe_sel.si_note, 1);
cpipe->pipe_present = PIPE_FINALIZED;
seldrain(&cpipe->pipe_sel);
knlist_destroy(&cpipe->pipe_sel.si_note);
/*
* If both endpoints are now closed, release the memory for the
* pipe pair. If not, unlock.
*/
if (ppipe->pipe_present == PIPE_FINALIZED) {
PIPE_UNLOCK(cpipe);
#ifdef MAC
mac_pipe_destroy(pp);
#endif
uma_zfree(pipe_zone, cpipe->pipe_pair);
} else
PIPE_UNLOCK(cpipe);
}
/*ARGSUSED*/
static int
pipe_kqfilter(struct file *fp, struct knote *kn)
{
struct pipe *cpipe;
/*
* If a filter is requested that is not supported by this file
* descriptor, don't return an error, but also don't ever generate an
* event.
*/
if ((kn->kn_filter == EVFILT_READ) && !(fp->f_flag & FREAD)) {
kn->kn_fop = &pipe_nfiltops;
return (0);
}
if ((kn->kn_filter == EVFILT_WRITE) && !(fp->f_flag & FWRITE)) {
kn->kn_fop = &pipe_nfiltops;
return (0);
}
cpipe = fp->f_data;
PIPE_LOCK(cpipe);
switch (kn->kn_filter) {
case EVFILT_READ:
kn->kn_fop = &pipe_rfiltops;
break;
case EVFILT_WRITE:
kn->kn_fop = &pipe_wfiltops;
if (cpipe->pipe_peer->pipe_present != PIPE_ACTIVE) {
/* other end of pipe has been closed */
PIPE_UNLOCK(cpipe);
return (EPIPE);
}
cpipe = PIPE_PEER(cpipe);
break;
default:
PIPE_UNLOCK(cpipe);
return (EINVAL);
}
kn->kn_hook = cpipe;
knlist_add(&cpipe->pipe_sel.si_note, kn, 1);
PIPE_UNLOCK(cpipe);
return (0);
}
static void
filt_pipedetach(struct knote *kn)
{
struct pipe *cpipe = kn->kn_hook;
PIPE_LOCK(cpipe);
knlist_remove(&cpipe->pipe_sel.si_note, kn, 1);
PIPE_UNLOCK(cpipe);
}
/*ARGSUSED*/
static int
filt_piperead(struct knote *kn, long hint)
{
struct pipe *rpipe = kn->kn_hook;
struct pipe *wpipe = rpipe->pipe_peer;
int ret;
PIPE_LOCK(rpipe);
kn->kn_data = rpipe->pipe_buffer.cnt;
if ((kn->kn_data == 0) && (rpipe->pipe_state & PIPE_DIRECTW))
kn->kn_data = rpipe->pipe_map.cnt;
if ((rpipe->pipe_state & PIPE_EOF) ||
wpipe->pipe_present != PIPE_ACTIVE ||
(wpipe->pipe_state & PIPE_EOF)) {
kn->kn_flags |= EV_EOF;
PIPE_UNLOCK(rpipe);
return (1);
}
ret = kn->kn_data > 0;
PIPE_UNLOCK(rpipe);
return ret;
}
/*ARGSUSED*/
static int
filt_pipewrite(struct knote *kn, long hint)
{
struct pipe *wpipe;
wpipe = kn->kn_hook;
PIPE_LOCK(wpipe);
if (wpipe->pipe_present != PIPE_ACTIVE ||
(wpipe->pipe_state & PIPE_EOF)) {
kn->kn_data = 0;
kn->kn_flags |= EV_EOF;
PIPE_UNLOCK(wpipe);
return (1);
}
kn->kn_data = (wpipe->pipe_buffer.size > 0) ?
(wpipe->pipe_buffer.size - wpipe->pipe_buffer.cnt) : PIPE_BUF;
if (wpipe->pipe_state & PIPE_DIRECTW)
kn->kn_data = 0;
PIPE_UNLOCK(wpipe);
return (kn->kn_data >= PIPE_BUF);
}
static void
filt_pipedetach_notsup(struct knote *kn)
{
}
static int
filt_pipenotsup(struct knote *kn, long hint)
{
return (0);
}