2 * Copyright (c) 1996 John S. Dyson
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice immediately at the beginning of the file, without modification,
10 * this list of conditions, and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * 3. Absolutely no warranty of function or purpose is made by the author
16 * 4. Modifications may be freely made to this file if the above conditions
19 * $FreeBSD: src/sys/kern/sys_pipe.c,v 1.60.2.13 2002/08/05 15:05:15 des Exp $
23 * This file contains a high-performance replacement for the socket-based
24 * pipes scheme originally used in FreeBSD/4.4Lite. It does not support
25 * all features of sockets, but does do everything that pipes normally
28 #include <sys/param.h>
29 #include <sys/systm.h>
30 #include <sys/kernel.h>
32 #include <sys/fcntl.h>
34 #include <sys/filedesc.h>
35 #include <sys/filio.h>
36 #include <sys/ttycom.h>
38 #include <sys/signalvar.h>
39 #include <sys/sysproto.h>
41 #include <sys/vnode.h>
43 #include <sys/event.h>
44 #include <sys/globaldata.h>
45 #include <sys/module.h>
46 #include <sys/malloc.h>
47 #include <sys/sysctl.h>
48 #include <sys/socket.h>
49 #include <sys/kern_syscall.h>
52 #include <vm/vm_param.h>
54 #include <vm/vm_object.h>
55 #include <vm/vm_kern.h>
56 #include <vm/vm_extern.h>
58 #include <vm/vm_map.h>
59 #include <vm/vm_page.h>
60 #include <vm/vm_zone.h>
62 #include <sys/file2.h>
63 #include <sys/signal2.h>
65 #include <machine/cpufunc.h>
68 * interfaces to the outside world
70 static int pipe_read (struct file *fp, struct uio *uio,
71 struct ucred *cred, int flags);
72 static int pipe_write (struct file *fp, struct uio *uio,
73 struct ucred *cred, int flags);
74 static int pipe_close (struct file *fp);
75 static int pipe_shutdown (struct file *fp, int how);
76 static int pipe_kqfilter (struct file *fp, struct knote *kn);
77 static int pipe_stat (struct file *fp, struct stat *sb, struct ucred *cred);
78 static int pipe_ioctl (struct file *fp, u_long cmd, caddr_t data,
79 struct ucred *cred, struct sysmsg *msg);
81 static struct fileops pipeops = {
83 .fo_write = pipe_write,
84 .fo_ioctl = pipe_ioctl,
85 .fo_kqfilter = pipe_kqfilter,
87 .fo_close = pipe_close,
88 .fo_shutdown = pipe_shutdown
91 static void filt_pipedetach(struct knote *kn);
92 static int filt_piperead(struct knote *kn, long hint);
93 static int filt_pipewrite(struct knote *kn, long hint);
95 static struct filterops pipe_rfiltops =
96 { FILTEROP_ISFD|FILTEROP_MPSAFE, NULL, filt_pipedetach, filt_piperead };
97 static struct filterops pipe_wfiltops =
98 { FILTEROP_ISFD|FILTEROP_MPSAFE, NULL, filt_pipedetach, filt_pipewrite };
100 MALLOC_DEFINE(M_PIPE, "pipe", "pipe structures");
103 * Default pipe buffer size(s), this can be kind-of large now because pipe
104 * space is pageable. The pipe code will try to maintain locality of
105 * reference for performance reasons, so small amounts of outstanding I/O
106 * will not wipe the cache.
108 #define MINPIPESIZE (PIPE_SIZE/3)
109 #define MAXPIPESIZE (2*PIPE_SIZE/3)
112 * Limit the number of "big" pipes
114 #define LIMITBIGPIPES 64
115 #define PIPEQ_MAX_CACHE 16 /* per-cpu pipe structure cache */
117 static int pipe_maxbig = LIMITBIGPIPES;
118 static int pipe_maxcache = PIPEQ_MAX_CACHE;
119 static int pipe_bigcount;
120 static int pipe_nbig;
121 static int pipe_bcache_alloc;
122 static int pipe_bkmem_alloc;
123 static int pipe_rblocked_count;
124 static int pipe_wblocked_count;
126 SYSCTL_NODE(_kern, OID_AUTO, pipe, CTLFLAG_RW, 0, "Pipe operation");
127 SYSCTL_INT(_kern_pipe, OID_AUTO, nbig,
128 CTLFLAG_RD, &pipe_nbig, 0, "number of big pipes allocated");
129 SYSCTL_INT(_kern_pipe, OID_AUTO, bigcount,
130 CTLFLAG_RW, &pipe_bigcount, 0, "number of times pipe expanded");
131 SYSCTL_INT(_kern_pipe, OID_AUTO, rblocked,
132 CTLFLAG_RW, &pipe_rblocked_count, 0, "number of times pipe expanded");
133 SYSCTL_INT(_kern_pipe, OID_AUTO, wblocked,
134 CTLFLAG_RW, &pipe_wblocked_count, 0, "number of times pipe expanded");
135 SYSCTL_INT(_kern_pipe, OID_AUTO, maxcache,
136 CTLFLAG_RW, &pipe_maxcache, 0, "max pipes cached per-cpu");
137 SYSCTL_INT(_kern_pipe, OID_AUTO, maxbig,
138 CTLFLAG_RW, &pipe_maxbig, 0, "max number of big pipes");
139 static int pipe_delay = 5000; /* 5uS default */
140 SYSCTL_INT(_kern_pipe, OID_AUTO, delay,
141 CTLFLAG_RW, &pipe_delay, 0, "SMP delay optimization in ns");
142 #if !defined(NO_PIPE_SYSCTL_STATS)
143 SYSCTL_INT(_kern_pipe, OID_AUTO, bcache_alloc,
144 CTLFLAG_RW, &pipe_bcache_alloc, 0, "pipe buffer from pcpu cache");
145 SYSCTL_INT(_kern_pipe, OID_AUTO, bkmem_alloc,
146 CTLFLAG_RW, &pipe_bkmem_alloc, 0, "pipe buffer from kmem");
150 * Auto-size pipe cache to reduce kmem allocations and frees.
154 pipeinit(void *dummy)
156 size_t mbytes = kmem_lim_size();
158 if (pipe_maxbig == LIMITBIGPIPES) {
159 if (mbytes >= 7 * 1024)
161 if (mbytes >= 15 * 1024)
164 if (pipe_maxcache == PIPEQ_MAX_CACHE) {
165 if (mbytes >= 7 * 1024)
167 if (mbytes >= 15 * 1024)
171 SYSINIT(kmem, SI_BOOT2_MACHDEP, SI_ORDER_ANY, pipeinit, NULL);
173 static void pipeclose (struct pipe *cpipe);
174 static void pipe_free_kmem (struct pipe *cpipe);
175 static int pipe_create (struct pipe **cpipep);
176 static int pipespace (struct pipe *cpipe, int size);
179 pipewakeup(struct pipe *cpipe, int dosigio)
181 if (dosigio && (cpipe->pipe_state & PIPE_ASYNC) && cpipe->pipe_sigio) {
182 lwkt_gettoken(&sigio_token);
183 pgsigio(cpipe->pipe_sigio, SIGIO, 0);
184 lwkt_reltoken(&sigio_token);
186 KNOTE(&cpipe->pipe_kq.ki_note, 0);
190 * These routines are called before and after a UIO. The UIO
191 * may block, causing our held tokens to be lost temporarily.
193 * We use these routines to serialize reads against other reads
194 * and writes against other writes.
196 * The read token is held on entry so *ipp does not race.
199 pipe_start_uio(struct pipe *cpipe, int *ipp)
205 error = tsleep(ipp, PCATCH, "pipexx", 0);
214 pipe_end_uio(struct pipe *cpipe, int *ipp)
226 * The pipe system call for the DTYPE_PIPE type of pipes
228 * pipe_args(int dummy)
233 sys_pipe(struct pipe_args *uap)
235 return kern_pipe(uap->sysmsg_fds, 0);
239 sys_pipe2(struct pipe2_args *uap)
241 return kern_pipe(uap->sysmsg_fds, uap->flags);
245 kern_pipe(long *fds, int flags)
247 struct thread *td = curthread;
248 struct filedesc *fdp = td->td_proc->p_fd;
249 struct file *rf, *wf;
250 struct pipe *rpipe, *wpipe;
253 rpipe = wpipe = NULL;
254 if (pipe_create(&rpipe) || pipe_create(&wpipe)) {
260 error = falloc(td->td_lwp, &rf, &fd1);
269 * Warning: once we've gotten past allocation of the fd for the
270 * read-side, we can only drop the read side via fdrop() in order
271 * to avoid races against processes which manage to dup() the read
272 * side while we are blocked trying to allocate the write side.
274 rf->f_type = DTYPE_PIPE;
275 rf->f_flag = FREAD | FWRITE;
276 rf->f_ops = &pipeops;
278 if (flags & O_NONBLOCK)
279 rf->f_flag |= O_NONBLOCK;
280 if (flags & O_CLOEXEC)
281 fdp->fd_files[fd1].fileflags |= UF_EXCLOSE;
283 error = falloc(td->td_lwp, &wf, &fd2);
285 fsetfd(fdp, NULL, fd1);
287 /* rpipe has been closed by fdrop(). */
291 wf->f_type = DTYPE_PIPE;
292 wf->f_flag = FREAD | FWRITE;
293 wf->f_ops = &pipeops;
295 if (flags & O_NONBLOCK)
296 wf->f_flag |= O_NONBLOCK;
297 if (flags & O_CLOEXEC)
298 fdp->fd_files[fd2].fileflags |= UF_EXCLOSE;
302 rpipe->pipe_slock = kmalloc(sizeof(struct lock),
303 M_PIPE, M_WAITOK|M_ZERO);
304 wpipe->pipe_slock = rpipe->pipe_slock;
305 rpipe->pipe_peer = wpipe;
306 wpipe->pipe_peer = rpipe;
307 lockinit(rpipe->pipe_slock, "pipecl", 0, 0);
310 * Once activated the peer relationship remains valid until
311 * both sides are closed.
313 fsetfd(fdp, rf, fd1);
314 fsetfd(fdp, wf, fd2);
322 * Allocate kva for pipe circular buffer, the space is pageable
323 * This routine will 'realloc' the size of a pipe safely, if it fails
324 * it will retain the old buffer.
325 * If it fails it will return ENOMEM.
328 pipespace(struct pipe *cpipe, int size)
330 struct vm_object *object;
334 npages = round_page(size) / PAGE_SIZE;
335 object = cpipe->pipe_buffer.object;
338 * [re]create the object if necessary and reserve space for it
339 * in the kernel_map. The object and memory are pageable. On
340 * success, free the old resources before assigning the new
343 if (object == NULL || object->size != npages) {
344 object = vm_object_allocate(OBJT_DEFAULT, npages);
345 buffer = (caddr_t)vm_map_min(&kernel_map);
347 error = vm_map_find(&kernel_map, object, NULL,
348 0, (vm_offset_t *)&buffer, size,
350 1, VM_MAPTYPE_NORMAL,
351 VM_PROT_ALL, VM_PROT_ALL, 0);
353 if (error != KERN_SUCCESS) {
354 vm_object_deallocate(object);
357 pipe_free_kmem(cpipe);
358 cpipe->pipe_buffer.object = object;
359 cpipe->pipe_buffer.buffer = buffer;
360 cpipe->pipe_buffer.size = size;
365 cpipe->pipe_buffer.rindex = 0;
366 cpipe->pipe_buffer.windex = 0;
371 * Initialize and allocate VM and memory for pipe, pulling the pipe from
372 * our per-cpu cache if possible. For now make sure it is sized for the
373 * smaller PIPE_SIZE default.
376 pipe_create(struct pipe **cpipep)
378 globaldata_t gd = mycpu;
382 if ((cpipe = gd->gd_pipeq) != NULL) {
383 gd->gd_pipeq = cpipe->pipe_peer;
385 cpipe->pipe_peer = NULL;
386 cpipe->pipe_wantwcnt = 0;
388 cpipe = kmalloc(sizeof(struct pipe), M_PIPE, M_WAITOK|M_ZERO);
391 if ((error = pipespace(cpipe, PIPE_SIZE)) != 0)
393 vfs_timestamp(&cpipe->pipe_ctime);
394 cpipe->pipe_atime = cpipe->pipe_ctime;
395 cpipe->pipe_mtime = cpipe->pipe_ctime;
396 lwkt_token_init(&cpipe->pipe_rlock, "piper");
397 lwkt_token_init(&cpipe->pipe_wlock, "pipew");
402 pipe_read(struct file *fp, struct uio *uio, struct ucred *cred, int fflags)
409 u_int size; /* total bytes available */
410 u_int nsize; /* total bytes to read */
411 u_int rindex; /* contiguous bytes available */
416 atomic_set_int(&curthread->td_mpflags, TDF_MP_BATCH_DEMARC);
418 if (uio->uio_resid == 0)
422 * Setup locks, calculate nbio
424 rpipe = (struct pipe *)fp->f_data;
425 wpipe = rpipe->pipe_peer;
426 lwkt_gettoken(&rpipe->pipe_rlock);
428 if (fflags & O_FBLOCKING)
430 else if (fflags & O_FNONBLOCKING)
432 else if (fp->f_flag & O_NONBLOCK)
438 * Reads are serialized. Note however that pipe_buffer.buffer and
439 * pipe_buffer.size can change out from under us when the number
440 * of bytes in the buffer are zero due to the write-side doing a
443 error = pipe_start_uio(rpipe, &rpipe->pipe_rip);
445 lwkt_reltoken(&rpipe->pipe_rlock);
450 bigread = (uio->uio_resid > 10 * 1024 * 1024);
453 while (uio->uio_resid) {
457 if (bigread && --bigcount == 0) {
460 if (CURSIG(curthread->td_lwp)) {
466 size = rpipe->pipe_buffer.windex - rpipe->pipe_buffer.rindex;
469 rindex = rpipe->pipe_buffer.rindex &
470 (rpipe->pipe_buffer.size - 1);
472 if (nsize > rpipe->pipe_buffer.size - rindex)
473 nsize = rpipe->pipe_buffer.size - rindex;
474 nsize = szmin(nsize, uio->uio_resid);
476 error = uiomove(&rpipe->pipe_buffer.buffer[rindex],
481 rpipe->pipe_buffer.rindex += nsize;
485 * If the FIFO is still over half full just continue
486 * and do not try to notify the writer yet.
488 if (size - nsize >= (rpipe->pipe_buffer.size >> 1)) {
494 * When the FIFO is less then half full notify any
495 * waiting writer. WANTW can be checked while
496 * holding just the rlock.
499 if ((rpipe->pipe_state & PIPE_WANTW) == 0)
504 * If the "write-side" was blocked we wake it up. This code
505 * is reached either when the buffer is completely emptied
506 * or if it becomes more then half-empty.
508 * Pipe_state can only be modified if both the rlock and
511 if (rpipe->pipe_state & PIPE_WANTW) {
512 lwkt_gettoken(&rpipe->pipe_wlock);
513 if (rpipe->pipe_state & PIPE_WANTW) {
514 rpipe->pipe_state &= ~PIPE_WANTW;
515 lwkt_reltoken(&rpipe->pipe_wlock);
518 lwkt_reltoken(&rpipe->pipe_wlock);
523 * Pick up our copy loop again if the writer sent data to
524 * us while we were messing around.
526 * On a SMP box poll up to pipe_delay nanoseconds for new
527 * data. Typically a value of 2000 to 4000 is sufficient
528 * to eradicate most IPIs/tsleeps/wakeups when a pipe
529 * is used for synchronous communications with small packets,
530 * and 8000 or so (8uS) will pipeline large buffer xfers
531 * between cpus over a pipe.
533 * For synchronous communications a hit means doing a
534 * full Awrite-Bread-Bwrite-Aread cycle in less then 2uS,
535 * where as miss requiring a tsleep/wakeup sequence
536 * will take 7uS or more.
538 if (rpipe->pipe_buffer.windex != rpipe->pipe_buffer.rindex)
541 #ifdef _RDTSC_SUPPORTED_
546 tsc_target = tsc_get_target(pipe_delay);
547 while (tsc_test_target(tsc_target) == 0) {
548 if (rpipe->pipe_buffer.windex !=
549 rpipe->pipe_buffer.rindex) {
560 * Detect EOF condition, do not set error.
562 if (rpipe->pipe_state & PIPE_REOF)
566 * Break if some data was read, or if this was a non-blocking
578 * Last chance, interlock with WANTR.
580 lwkt_gettoken(&rpipe->pipe_wlock);
581 size = rpipe->pipe_buffer.windex - rpipe->pipe_buffer.rindex;
583 lwkt_reltoken(&rpipe->pipe_wlock);
588 * Retest EOF - acquiring a new token can temporarily release
589 * tokens already held.
591 if (rpipe->pipe_state & PIPE_REOF) {
592 lwkt_reltoken(&rpipe->pipe_wlock);
597 * If there is no more to read in the pipe, reset its
598 * pointers to the beginning. This improves cache hit
601 * We need both locks to modify both pointers, and there
602 * must also not be a write in progress or the uiomove()
603 * in the write might block and temporarily release
604 * its wlock, then reacquire and update windex. We are
605 * only serialized against reads, not writes.
607 * XXX should we even bother resetting the indices? It
608 * might actually be more cache efficient not to.
610 if (rpipe->pipe_buffer.rindex == rpipe->pipe_buffer.windex &&
611 rpipe->pipe_wip == 0) {
612 rpipe->pipe_buffer.rindex = 0;
613 rpipe->pipe_buffer.windex = 0;
617 * Wait for more data.
619 * Pipe_state can only be set if both the rlock and wlock
622 rpipe->pipe_state |= PIPE_WANTR;
623 tsleep_interlock(rpipe, PCATCH);
624 lwkt_reltoken(&rpipe->pipe_wlock);
625 error = tsleep(rpipe, PCATCH | PINTERLOCKED, "piperd", 0);
626 ++pipe_rblocked_count;
630 pipe_end_uio(rpipe, &rpipe->pipe_rip);
633 * Uptime last access time
635 if (error == 0 && nread)
636 vfs_timestamp(&rpipe->pipe_atime);
639 * If we drained the FIFO more then half way then handle
640 * write blocking hysteresis.
642 * Note that PIPE_WANTW cannot be set by the writer without
643 * it holding both rlock and wlock, so we can test it
644 * while holding just rlock.
648 * Synchronous blocking is done on the pipe involved
650 if (rpipe->pipe_state & PIPE_WANTW) {
651 lwkt_gettoken(&rpipe->pipe_wlock);
652 if (rpipe->pipe_state & PIPE_WANTW) {
653 rpipe->pipe_state &= ~PIPE_WANTW;
654 lwkt_reltoken(&rpipe->pipe_wlock);
657 lwkt_reltoken(&rpipe->pipe_wlock);
662 * But we may also have to deal with a kqueue which is
663 * stored on the same pipe as its descriptor, so a
664 * EVFILT_WRITE event waiting for our side to drain will
665 * be on the other side.
667 lwkt_gettoken(&wpipe->pipe_wlock);
668 pipewakeup(wpipe, 0);
669 lwkt_reltoken(&wpipe->pipe_wlock);
671 /*size = rpipe->pipe_buffer.windex - rpipe->pipe_buffer.rindex;*/
672 lwkt_reltoken(&rpipe->pipe_rlock);
678 pipe_write(struct file *fp, struct uio *uio, struct ucred *cred, int fflags)
692 * Writes go to the peer. The peer will always exist.
694 rpipe = (struct pipe *) fp->f_data;
695 wpipe = rpipe->pipe_peer;
696 lwkt_gettoken(&wpipe->pipe_wlock);
697 if (wpipe->pipe_state & PIPE_WEOF) {
698 lwkt_reltoken(&wpipe->pipe_wlock);
703 * Degenerate case (EPIPE takes prec)
705 if (uio->uio_resid == 0) {
706 lwkt_reltoken(&wpipe->pipe_wlock);
711 * Writes are serialized (start_uio must be called with wlock)
713 error = pipe_start_uio(wpipe, &wpipe->pipe_wip);
715 lwkt_reltoken(&wpipe->pipe_wlock);
719 if (fflags & O_FBLOCKING)
721 else if (fflags & O_FNONBLOCKING)
723 else if (fp->f_flag & O_NONBLOCK)
729 * If it is advantageous to resize the pipe buffer, do
730 * so. We are write-serialized so we can block safely.
732 if ((wpipe->pipe_buffer.size <= PIPE_SIZE) &&
733 (pipe_nbig < pipe_maxbig) &&
734 wpipe->pipe_wantwcnt > 4 &&
735 (wpipe->pipe_buffer.rindex == wpipe->pipe_buffer.windex)) {
737 * Recheck after lock.
739 lwkt_gettoken(&wpipe->pipe_rlock);
740 if ((wpipe->pipe_buffer.size <= PIPE_SIZE) &&
741 (pipe_nbig < pipe_maxbig) &&
742 (wpipe->pipe_buffer.rindex == wpipe->pipe_buffer.windex)) {
743 atomic_add_int(&pipe_nbig, 1);
744 if (pipespace(wpipe, BIG_PIPE_SIZE) == 0)
747 atomic_subtract_int(&pipe_nbig, 1);
749 lwkt_reltoken(&wpipe->pipe_rlock);
752 orig_resid = uio->uio_resid;
755 bigwrite = (uio->uio_resid > 10 * 1024 * 1024);
758 while (uio->uio_resid) {
759 if (wpipe->pipe_state & PIPE_WEOF) {
767 if (bigwrite && --bigcount == 0) {
770 if (CURSIG(curthread->td_lwp)) {
776 windex = wpipe->pipe_buffer.windex &
777 (wpipe->pipe_buffer.size - 1);
778 space = wpipe->pipe_buffer.size -
779 (wpipe->pipe_buffer.windex - wpipe->pipe_buffer.rindex);
782 /* Writes of size <= PIPE_BUF must be atomic. */
783 if ((space < uio->uio_resid) && (orig_resid <= PIPE_BUF))
787 * Write to fill, read size handles write hysteresis. Also
788 * additional restrictions can cause select-based non-blocking
795 * Transfer size is minimum of uio transfer
796 * and free space in pipe buffer.
798 * Limit each uiocopy to no more then PIPE_SIZE
799 * so we can keep the gravy train going on a
800 * SMP box. This doubles the performance for
801 * write sizes > 16K. Otherwise large writes
802 * wind up doing an inefficient synchronous
805 space = szmin(space, uio->uio_resid);
806 if (space > PIPE_SIZE)
810 * First segment to transfer is minimum of
811 * transfer size and contiguous space in
812 * pipe buffer. If first segment to transfer
813 * is less than the transfer size, we've got
814 * a wraparound in the buffer.
816 segsize = wpipe->pipe_buffer.size - windex;
821 * If this is the first loop and the reader is
822 * blocked, do a preemptive wakeup of the reader.
824 * On SMP the IPI latency plus the wlock interlock
825 * on the reader side is the fastest way to get the
826 * reader going. (The scheduler will hard loop on
829 * NOTE: We can't clear WANTR here without acquiring
830 * the rlock, which we don't want to do here!
832 if ((wpipe->pipe_state & PIPE_WANTR))
836 * Transfer segment, which may include a wrap-around.
837 * Update windex to account for both all in one go
838 * so the reader can read() the data atomically.
840 error = uiomove(&wpipe->pipe_buffer.buffer[windex],
842 if (error == 0 && segsize < space) {
843 segsize = space - segsize;
844 error = uiomove(&wpipe->pipe_buffer.buffer[0],
850 wpipe->pipe_buffer.windex += space;
856 * We need both the rlock and the wlock to interlock against
857 * the EOF, WANTW, and size checks, and to modify pipe_state.
859 * These are token locks so we do not have to worry about
862 lwkt_gettoken(&wpipe->pipe_rlock);
865 * If the "read-side" has been blocked, wake it up now
866 * and yield to let it drain synchronously rather
869 if (wpipe->pipe_state & PIPE_WANTR) {
870 wpipe->pipe_state &= ~PIPE_WANTR;
875 * don't block on non-blocking I/O
878 lwkt_reltoken(&wpipe->pipe_rlock);
884 * re-test whether we have to block in the writer after
885 * acquiring both locks, in case the reader opened up
888 space = wpipe->pipe_buffer.size -
889 (wpipe->pipe_buffer.windex - wpipe->pipe_buffer.rindex);
891 if ((space < uio->uio_resid) && (orig_resid <= PIPE_BUF))
895 * Retest EOF - acquiring a new token can temporarily release
896 * tokens already held.
898 if (wpipe->pipe_state & PIPE_WEOF) {
899 lwkt_reltoken(&wpipe->pipe_rlock);
905 * We have no more space and have something to offer,
906 * wake up select/poll/kq.
909 wpipe->pipe_state |= PIPE_WANTW;
910 ++wpipe->pipe_wantwcnt;
911 pipewakeup(wpipe, 1);
912 if (wpipe->pipe_state & PIPE_WANTW)
913 error = tsleep(wpipe, PCATCH, "pipewr", 0);
914 ++pipe_wblocked_count;
916 lwkt_reltoken(&wpipe->pipe_rlock);
919 * Break out if we errored or the read side wants us to go
924 if (wpipe->pipe_state & PIPE_WEOF) {
929 pipe_end_uio(wpipe, &wpipe->pipe_wip);
932 * If we have put any characters in the buffer, we wake up
935 * Both rlock and wlock are required to be able to modify pipe_state.
937 if (wpipe->pipe_buffer.windex != wpipe->pipe_buffer.rindex) {
938 if (wpipe->pipe_state & PIPE_WANTR) {
939 lwkt_gettoken(&wpipe->pipe_rlock);
940 if (wpipe->pipe_state & PIPE_WANTR) {
941 wpipe->pipe_state &= ~PIPE_WANTR;
942 lwkt_reltoken(&wpipe->pipe_rlock);
945 lwkt_reltoken(&wpipe->pipe_rlock);
948 lwkt_gettoken(&wpipe->pipe_rlock);
949 pipewakeup(wpipe, 1);
950 lwkt_reltoken(&wpipe->pipe_rlock);
954 * Don't return EPIPE if I/O was successful
956 if ((wpipe->pipe_buffer.rindex == wpipe->pipe_buffer.windex) &&
957 (uio->uio_resid == 0) &&
963 vfs_timestamp(&wpipe->pipe_mtime);
966 * We have something to offer,
967 * wake up select/poll/kq.
969 /*space = wpipe->pipe_buffer.windex - wpipe->pipe_buffer.rindex;*/
970 lwkt_reltoken(&wpipe->pipe_wlock);
975 * we implement a very minimal set of ioctls for compatibility with sockets.
978 pipe_ioctl(struct file *fp, u_long cmd, caddr_t data,
979 struct ucred *cred, struct sysmsg *msg)
984 mpipe = (struct pipe *)fp->f_data;
986 lwkt_gettoken(&mpipe->pipe_rlock);
987 lwkt_gettoken(&mpipe->pipe_wlock);
992 mpipe->pipe_state |= PIPE_ASYNC;
994 mpipe->pipe_state &= ~PIPE_ASYNC;
999 *(int *)data = mpipe->pipe_buffer.windex -
1000 mpipe->pipe_buffer.rindex;
1004 error = fsetown(*(int *)data, &mpipe->pipe_sigio);
1007 *(int *)data = fgetown(&mpipe->pipe_sigio);
1011 /* This is deprecated, FIOSETOWN should be used instead. */
1012 error = fsetown(-(*(int *)data), &mpipe->pipe_sigio);
1016 /* This is deprecated, FIOGETOWN should be used instead. */
1017 *(int *)data = -fgetown(&mpipe->pipe_sigio);
1024 lwkt_reltoken(&mpipe->pipe_wlock);
1025 lwkt_reltoken(&mpipe->pipe_rlock);
1034 pipe_stat(struct file *fp, struct stat *ub, struct ucred *cred)
1038 pipe = (struct pipe *)fp->f_data;
1040 bzero((caddr_t)ub, sizeof(*ub));
1041 ub->st_mode = S_IFIFO;
1042 ub->st_blksize = pipe->pipe_buffer.size;
1043 ub->st_size = pipe->pipe_buffer.windex - pipe->pipe_buffer.rindex;
1044 ub->st_blocks = (ub->st_size + ub->st_blksize - 1) / ub->st_blksize;
1045 ub->st_atimespec = pipe->pipe_atime;
1046 ub->st_mtimespec = pipe->pipe_mtime;
1047 ub->st_ctimespec = pipe->pipe_ctime;
1049 * Left as 0: st_dev, st_ino, st_nlink, st_uid, st_gid, st_rdev,
1051 * XXX (st_dev, st_ino) should be unique.
1057 pipe_close(struct file *fp)
1061 cpipe = (struct pipe *)fp->f_data;
1062 fp->f_ops = &badfileops;
1064 funsetown(&cpipe->pipe_sigio);
1070 * Shutdown one or both directions of a full-duplex pipe.
1073 pipe_shutdown(struct file *fp, int how)
1079 rpipe = (struct pipe *)fp->f_data;
1080 wpipe = rpipe->pipe_peer;
1083 * We modify pipe_state on both pipes, which means we need
1086 lwkt_gettoken(&rpipe->pipe_rlock);
1087 lwkt_gettoken(&rpipe->pipe_wlock);
1088 lwkt_gettoken(&wpipe->pipe_rlock);
1089 lwkt_gettoken(&wpipe->pipe_wlock);
1094 rpipe->pipe_state |= PIPE_REOF; /* my reads */
1095 rpipe->pipe_state |= PIPE_WEOF; /* peer writes */
1096 if (rpipe->pipe_state & PIPE_WANTR) {
1097 rpipe->pipe_state &= ~PIPE_WANTR;
1100 if (rpipe->pipe_state & PIPE_WANTW) {
1101 rpipe->pipe_state &= ~PIPE_WANTW;
1109 wpipe->pipe_state |= PIPE_REOF; /* peer reads */
1110 wpipe->pipe_state |= PIPE_WEOF; /* my writes */
1111 if (wpipe->pipe_state & PIPE_WANTR) {
1112 wpipe->pipe_state &= ~PIPE_WANTR;
1115 if (wpipe->pipe_state & PIPE_WANTW) {
1116 wpipe->pipe_state &= ~PIPE_WANTW;
1122 pipewakeup(rpipe, 1);
1123 pipewakeup(wpipe, 1);
1125 lwkt_reltoken(&wpipe->pipe_wlock);
1126 lwkt_reltoken(&wpipe->pipe_rlock);
1127 lwkt_reltoken(&rpipe->pipe_wlock);
1128 lwkt_reltoken(&rpipe->pipe_rlock);
1134 pipe_free_kmem(struct pipe *cpipe)
1136 if (cpipe->pipe_buffer.buffer != NULL) {
1137 if (cpipe->pipe_buffer.size > PIPE_SIZE)
1138 atomic_subtract_int(&pipe_nbig, 1);
1139 kmem_free(&kernel_map,
1140 (vm_offset_t)cpipe->pipe_buffer.buffer,
1141 cpipe->pipe_buffer.size);
1142 cpipe->pipe_buffer.buffer = NULL;
1143 cpipe->pipe_buffer.object = NULL;
1148 * Close the pipe. The slock must be held to interlock against simultanious
1149 * closes. The rlock and wlock must be held to adjust the pipe_state.
1152 pipeclose(struct pipe *cpipe)
1161 * The slock may not have been allocated yet (close during
1164 * We need both the read and write tokens to modify pipe_state.
1166 if (cpipe->pipe_slock)
1167 lockmgr(cpipe->pipe_slock, LK_EXCLUSIVE);
1168 lwkt_gettoken(&cpipe->pipe_rlock);
1169 lwkt_gettoken(&cpipe->pipe_wlock);
1172 * Set our state, wakeup anyone waiting in select/poll/kq, and
1173 * wakeup anyone blocked on our pipe.
1175 cpipe->pipe_state |= PIPE_CLOSED | PIPE_REOF | PIPE_WEOF;
1176 pipewakeup(cpipe, 1);
1177 if (cpipe->pipe_state & (PIPE_WANTR | PIPE_WANTW)) {
1178 cpipe->pipe_state &= ~(PIPE_WANTR | PIPE_WANTW);
1183 * Disconnect from peer.
1185 if ((ppipe = cpipe->pipe_peer) != NULL) {
1186 lwkt_gettoken(&ppipe->pipe_rlock);
1187 lwkt_gettoken(&ppipe->pipe_wlock);
1188 ppipe->pipe_state |= PIPE_REOF | PIPE_WEOF;
1189 pipewakeup(ppipe, 1);
1190 if (ppipe->pipe_state & (PIPE_WANTR | PIPE_WANTW)) {
1191 ppipe->pipe_state &= ~(PIPE_WANTR | PIPE_WANTW);
1194 if (SLIST_FIRST(&ppipe->pipe_kq.ki_note))
1195 KNOTE(&ppipe->pipe_kq.ki_note, 0);
1196 lwkt_reltoken(&ppipe->pipe_wlock);
1197 lwkt_reltoken(&ppipe->pipe_rlock);
1201 * If the peer is also closed we can free resources for both
1202 * sides, otherwise we leave our side intact to deal with any
1203 * races (since we only have the slock).
1205 if (ppipe && (ppipe->pipe_state & PIPE_CLOSED)) {
1206 cpipe->pipe_peer = NULL;
1207 ppipe->pipe_peer = NULL;
1208 ppipe->pipe_slock = NULL; /* we will free the slock */
1213 lwkt_reltoken(&cpipe->pipe_wlock);
1214 lwkt_reltoken(&cpipe->pipe_rlock);
1215 if (cpipe->pipe_slock)
1216 lockmgr(cpipe->pipe_slock, LK_RELEASE);
1219 * If we disassociated from our peer we can free resources
1221 if (ppipe == NULL) {
1223 if (cpipe->pipe_slock) {
1224 kfree(cpipe->pipe_slock, M_PIPE);
1225 cpipe->pipe_slock = NULL;
1227 if (gd->gd_pipeqcount >= pipe_maxcache ||
1228 cpipe->pipe_buffer.size != PIPE_SIZE
1230 pipe_free_kmem(cpipe);
1231 kfree(cpipe, M_PIPE);
1233 cpipe->pipe_state = 0;
1234 cpipe->pipe_peer = gd->gd_pipeq;
1235 gd->gd_pipeq = cpipe;
1236 ++gd->gd_pipeqcount;
1242 pipe_kqfilter(struct file *fp, struct knote *kn)
1246 cpipe = (struct pipe *)kn->kn_fp->f_data;
1248 switch (kn->kn_filter) {
1250 kn->kn_fop = &pipe_rfiltops;
1253 kn->kn_fop = &pipe_wfiltops;
1254 if (cpipe->pipe_peer == NULL) {
1255 /* other end of pipe has been closed */
1260 return (EOPNOTSUPP);
1262 kn->kn_hook = (caddr_t)cpipe;
1264 knote_insert(&cpipe->pipe_kq.ki_note, kn);
1270 filt_pipedetach(struct knote *kn)
1272 struct pipe *cpipe = (struct pipe *)kn->kn_hook;
1274 knote_remove(&cpipe->pipe_kq.ki_note, kn);
1279 filt_piperead(struct knote *kn, long hint)
1281 struct pipe *rpipe = (struct pipe *)kn->kn_fp->f_data;
1284 lwkt_gettoken(&rpipe->pipe_rlock);
1285 lwkt_gettoken(&rpipe->pipe_wlock);
1287 kn->kn_data = rpipe->pipe_buffer.windex - rpipe->pipe_buffer.rindex;
1289 if (rpipe->pipe_state & PIPE_REOF) {
1291 * Only set NODATA if all data has been exhausted
1293 if (kn->kn_data == 0)
1294 kn->kn_flags |= EV_NODATA;
1295 kn->kn_flags |= EV_EOF;
1299 lwkt_reltoken(&rpipe->pipe_wlock);
1300 lwkt_reltoken(&rpipe->pipe_rlock);
1303 ready = kn->kn_data > 0;
1310 filt_pipewrite(struct knote *kn, long hint)
1312 struct pipe *rpipe = (struct pipe *)kn->kn_fp->f_data;
1313 struct pipe *wpipe = rpipe->pipe_peer;
1317 if (wpipe == NULL) {
1318 kn->kn_flags |= (EV_EOF | EV_NODATA);
1322 lwkt_gettoken(&wpipe->pipe_rlock);
1323 lwkt_gettoken(&wpipe->pipe_wlock);
1325 if (wpipe->pipe_state & PIPE_WEOF) {
1326 kn->kn_flags |= (EV_EOF | EV_NODATA);
1331 kn->kn_data = wpipe->pipe_buffer.size -
1332 (wpipe->pipe_buffer.windex -
1333 wpipe->pipe_buffer.rindex);
1335 lwkt_reltoken(&wpipe->pipe_wlock);
1336 lwkt_reltoken(&wpipe->pipe_rlock);
1339 ready = kn->kn_data >= PIPE_BUF;