[rtems-libbsd commit] PIPE(2): Import from FreeBSD
Sebastian Huber
sebh at rtems.org
Fri Dec 23 07:26:41 UTC 2016
Module: rtems-libbsd
Branch: master
Commit: 6959face72eeb3c0bf9e36eed3255ac9bd64424e
Changeset: http://git.rtems.org/rtems-libbsd/commit/?id=6959face72eeb3c0bf9e36eed3255ac9bd64424e
Author: Kevin Kirspel <kevin-kirspel at idexx.com>
Date: Wed Dec 21 11:01:26 2016 -0800
PIPE(2): Import from FreeBSD
---
freebsd/sys/kern/sys_pipe.c | 1689 +++++++++++++++++++++++++++++++++++++++++++
freebsd/sys/sys/pipe.h | 142 ++++
2 files changed, 1831 insertions(+)
diff --git a/freebsd/sys/kern/sys_pipe.c b/freebsd/sys/kern/sys_pipe.c
new file mode 100644
index 0000000..5565c00
--- /dev/null
+++ b/freebsd/sys/kern/sys_pipe.c
@@ -0,0 +1,1689 @@
+#include <machine/rtems-bsd-kernel-space.h>
+
+/*-
+ * Copyright (c) 1996 John S. Dyson
+ * 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 <rtems/bsd/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 <rtems/bsd/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 */
+
+/*
+ * 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 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 = invfo_chmod,
+ .fo_chown = invfo_chown,
+ .fo_flags = DFLAG_PASSABLE
+};
+
+static void filt_pipedetach(struct knote *kn);
+static int filt_piperead(struct knote *kn, long hint);
+static int filt_pipewrite(struct knote *kn, long hint);
+
+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 __inline int pipelock(struct pipe *cpipe, int catch);
+static __inline void pipeunlock(struct pipe *cpipe);
+static __inline void pipeselwakeup(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);
+}
+
+/*
+ * 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 = td->td_proc->p_fd;
+ struct file *rf, *wf;
+ struct pipepair *pp;
+ struct pipe *rpipe, *wpipe;
+ int fd, fflags, error;
+
+ 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;
+
+ 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);
+ }
+}
+
+static __inline 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 = fp->f_data;
+ int error;
+ int nread = 0;
+ int size;
+
+ 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;
+ 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);
+ 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 = rpipe->pipe_peer;
+
+ 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;
+{
+
+ 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 (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 = fp->f_data;
+ struct pipe *wpipe;
+ int revents = 0;
+#ifdef MAC
+ int error;
+#endif
+
+ wpipe = rpipe->pipe_peer;
+ PIPE_LOCK(rpipe);
+#ifdef MAC
+ error = mac_pipe_check_poll(active_cred, rpipe->pipe_pair);
+ if (error)
+ goto locked_error;
+#endif
+ if (events & (POLLIN | POLLRDNORM))
+ if ((rpipe->pipe_state & PIPE_DIRECTW) ||
+ (rpipe->pipe_buffer.cnt > 0))
+ revents |= events & (POLLIN | POLLRDNORM);
+
+ if (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);
+
+ 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 (events & (POLLIN | POLLRDNORM)) {
+ selrecord(td, &rpipe->pipe_sel);
+ if (SEL_WAITING(&rpipe->pipe_sel))
+ rpipe->pipe_state |= PIPE_SEL;
+ }
+
+ if (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
+ /*
+ * 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;
+{
+ struct pipe *cpipe = fp->f_data;
+
+ fp->f_ops = &badfileops;
+ fp->f_data = NULL;
+ funsetown(&cpipe->pipe_sigio);
+ pipeclose(cpipe);
+ return (0);
+}
+
+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;
+ ino_t ino;
+
+ 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);
+
+ /*
+ * Postpone the destroy of the fake inode number allocated for
+ * our end, until pipe mtx is unlocked.
+ */
+ ino = cpipe->pipe_ino;
+
+ /*
+ * 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);
+
+ if (ino != 0 && ino != (ino_t)-1)
+ free_unr(pipeino_unr, ino);
+}
+
+/*ARGSUSED*/
+static int
+pipe_kqfilter(struct file *fp, struct knote *kn)
+{
+ struct pipe *cpipe;
+
+ cpipe = kn->kn_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 = cpipe->pipe_peer;
+ break;
+ default:
+ PIPE_UNLOCK(cpipe);
+ return (EINVAL);
+ }
+
+ knlist_add(&cpipe->pipe_sel.si_note, kn, 1);
+ PIPE_UNLOCK(cpipe);
+ return (0);
+}
+
+static void
+filt_pipedetach(struct knote *kn)
+{
+ struct pipe *cpipe = (struct pipe *)kn->kn_fp->f_data;
+
+ PIPE_LOCK(cpipe);
+ if (kn->kn_filter == EVFILT_WRITE)
+ cpipe = cpipe->pipe_peer;
+ 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_fp->f_data;
+ 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 *rpipe = kn->kn_fp->f_data;
+ struct pipe *wpipe = rpipe->pipe_peer;
+
+ PIPE_LOCK(rpipe);
+ if (wpipe->pipe_present != PIPE_ACTIVE ||
+ (wpipe->pipe_state & PIPE_EOF)) {
+ kn->kn_data = 0;
+ kn->kn_flags |= EV_EOF;
+ PIPE_UNLOCK(rpipe);
+ 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(rpipe);
+ return (kn->kn_data >= PIPE_BUF);
+}
diff --git a/freebsd/sys/sys/pipe.h b/freebsd/sys/sys/pipe.h
new file mode 100644
index 0000000..444c8fb
--- /dev/null
+++ b/freebsd/sys/sys/pipe.h
@@ -0,0 +1,142 @@
+/*-
+ * Copyright (c) 1996 John S. Dyson
+ * 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. This work was done expressly for inclusion into FreeBSD. Other use
+ * is allowed if this notation is included.
+ * 5. Modifications may be freely made to this file if the above conditions
+ * are met.
+ *
+ * $FreeBSD$
+ */
+
+#ifndef _SYS_PIPE_H_
+#define _SYS_PIPE_H_
+
+#ifndef _KERNEL
+#error "no user-servicable parts inside"
+#endif
+
+/*
+ * Pipe buffer size, keep moderate in value, pipes take kva space.
+ */
+#ifndef PIPE_SIZE
+#define PIPE_SIZE 16384
+#endif
+
+#ifndef BIG_PIPE_SIZE
+#define BIG_PIPE_SIZE (64*1024)
+#endif
+
+#ifndef SMALL_PIPE_SIZE
+#define SMALL_PIPE_SIZE PAGE_SIZE
+#endif
+
+/*
+ * PIPE_MINDIRECT MUST be smaller than PIPE_SIZE and MUST be bigger
+ * than PIPE_BUF.
+ */
+#ifndef PIPE_MINDIRECT
+#define PIPE_MINDIRECT 8192
+#endif
+
+#define PIPENPAGES (BIG_PIPE_SIZE / PAGE_SIZE + 1)
+
+/*
+ * See sys_pipe.c for info on what these limits mean.
+ */
+extern long maxpipekva;
+
+/*
+ * Pipe buffer information.
+ * Separate in, out, cnt are used to simplify calculations.
+ * Buffered write is active when the buffer.cnt field is set.
+ */
+struct pipebuf {
+ u_int cnt; /* number of chars currently in buffer */
+ u_int in; /* in pointer */
+ u_int out; /* out pointer */
+ u_int size; /* size of buffer */
+ caddr_t buffer; /* kva of buffer */
+};
+
+/*
+ * Information to support direct transfers between processes for pipes.
+ */
+struct pipemapping {
+ vm_size_t cnt; /* number of chars in buffer */
+ vm_size_t pos; /* current position of transfer */
+ int npages; /* number of pages */
+ vm_page_t ms[PIPENPAGES]; /* pages in source process */
+};
+
+/*
+ * Bits in pipe_state.
+ */
+#define PIPE_ASYNC 0x004 /* Async? I/O. */
+#define PIPE_WANTR 0x008 /* Reader wants some characters. */
+#define PIPE_WANTW 0x010 /* Writer wants space to put characters. */
+#define PIPE_WANT 0x020 /* Pipe is wanted to be run-down. */
+#define PIPE_SEL 0x040 /* Pipe has a select active. */
+#define PIPE_EOF 0x080 /* Pipe is in EOF condition. */
+#define PIPE_LOCKFL 0x100 /* Process has exclusive access to pointers/data. */
+#define PIPE_LWANT 0x200 /* Process wants exclusive access to pointers/data. */
+#define PIPE_DIRECTW 0x400 /* Pipe direct write active. */
+#define PIPE_DIRECTOK 0x800 /* Direct mode ok. */
+
+/*
+ * Per-pipe data structure.
+ * Two of these are linked together to produce bi-directional pipes.
+ */
+struct pipe {
+ struct pipebuf pipe_buffer; /* data storage */
+ struct pipemapping pipe_map; /* pipe mapping for direct I/O */
+ struct selinfo pipe_sel; /* for compat with select */
+ struct timespec pipe_atime; /* time of last access */
+ struct timespec pipe_mtime; /* time of last modify */
+ struct timespec pipe_ctime; /* time of status change */
+ struct sigio *pipe_sigio; /* information for async I/O */
+ struct pipe *pipe_peer; /* link with other direction */
+ struct pipepair *pipe_pair; /* container structure pointer */
+ u_int pipe_state; /* pipe status info */
+ int pipe_busy; /* busy flag, mostly to handle rundown sanely */
+ int pipe_present; /* still present? */
+ ino_t pipe_ino; /* fake inode for stat(2) */
+};
+
+/*
+ * Values for the pipe_present.
+ */
+#define PIPE_ACTIVE 1
+#define PIPE_CLOSING 2
+#define PIPE_FINALIZED 3
+
+/*
+ * Container structure to hold the two pipe endpoints, mutex, and label
+ * pointer.
+ */
+struct pipepair {
+ struct pipe pp_rpipe;
+ struct pipe pp_wpipe;
+ struct mtx pp_mtx;
+ struct label *pp_label;
+};
+
+#define PIPE_MTX(pipe) (&(pipe)->pipe_pair->pp_mtx)
+#define PIPE_LOCK(pipe) mtx_lock(PIPE_MTX(pipe))
+#define PIPE_UNLOCK(pipe) mtx_unlock(PIPE_MTX(pipe))
+#define PIPE_LOCK_ASSERT(pipe, type) mtx_assert(PIPE_MTX(pipe), (type))
+
+
+#endif /* !_SYS_PIPE_H_ */
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