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Unbreak kernel build and fix some warnings.
[dragonfly.git] / sys / kern / sys_pipe.c
bloba256737a3bdaf6ab1fe98cd4da67d1b60e1a0918
1 /*
2 * Copyright (c) 1996 John S. Dyson
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
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
15 * John S. Dyson.
16 * 4. Modifications may be freely made to this file if the above conditions
17 * are met.
18 *
19 * $FreeBSD: src/sys/kern/sys_pipe.c,v 1.60.2.13 2002/08/05 15:05:15 des Exp $
20 * $DragonFly: src/sys/kern/sys_pipe.c,v 1.50 2008/09/09 04:06:13 dillon Exp $
21 */
22
23 /*
24 * This file contains a high-performance replacement for the socket-based
25 * pipes scheme originally used in FreeBSD/4.4Lite. It does not support
26 * all features of sockets, but does do everything that pipes normally
27 * do.
28 */
29
30 /*
31 * This code has two modes of operation, a small write mode and a large
32 * write mode. The small write mode acts like conventional pipes with
33 * a kernel buffer. If the buffer is less than PIPE_MINDIRECT, then the
34 * "normal" pipe buffering is done. If the buffer is between PIPE_MINDIRECT
35 * and PIPE_SIZE in size, it is fully mapped and wired into the kernel, and
36 * the receiving process can copy it directly from the pages in the sending
37 * process.
38 *
39 * If the sending process receives a signal, it is possible that it will
40 * go away, and certainly its address space can change, because control
41 * is returned back to the user-mode side. In that case, the pipe code
42 * arranges to copy the buffer supplied by the user process, to a pageable
43 * kernel buffer, and the receiving process will grab the data from the
44 * pageable kernel buffer. Since signals don't happen all that often,
45 * the copy operation is normally eliminated.
46 *
47 * The constant PIPE_MINDIRECT is chosen to make sure that buffering will
48 * happen for small transfers so that the system will not spend all of
49 * its time context switching. PIPE_SIZE is constrained by the
50 * amount of kernel virtual memory.
51 */
52
53 #include <sys/param.h>
54 #include <sys/systm.h>
55 #include <sys/kernel.h>
56 #include <sys/proc.h>
57 #include <sys/fcntl.h>
58 #include <sys/file.h>
59 #include <sys/filedesc.h>
60 #include <sys/filio.h>
61 #include <sys/ttycom.h>
62 #include <sys/stat.h>
63 #include <sys/poll.h>
64 #include <sys/select.h>
65 #include <sys/signalvar.h>
66 #include <sys/sysproto.h>
67 #include <sys/pipe.h>
68 #include <sys/vnode.h>
69 #include <sys/uio.h>
70 #include <sys/event.h>
71 #include <sys/globaldata.h>
72 #include <sys/module.h>
73 #include <sys/malloc.h>
74 #include <sys/sysctl.h>
75 #include <sys/socket.h>
76
77 #include <vm/vm.h>
78 #include <vm/vm_param.h>
79 #include <sys/lock.h>
80 #include <vm/vm_object.h>
81 #include <vm/vm_kern.h>
82 #include <vm/vm_extern.h>
83 #include <vm/pmap.h>
84 #include <vm/vm_map.h>
85 #include <vm/vm_page.h>
86 #include <vm/vm_zone.h>
87
88 #include <sys/file2.h>
89
90 #include <machine/cpufunc.h>
91
92 /*
93 * interfaces to the outside world
94 */
95 static int pipe_read (struct file *fp, struct uio *uio,
96 struct ucred *cred, int flags);
97 static int pipe_write (struct file *fp, struct uio *uio,
98 struct ucred *cred, int flags);
99 static int pipe_close (struct file *fp);
100 static int pipe_shutdown (struct file *fp, int how);
101 static int pipe_poll (struct file *fp, int events, struct ucred *cred);
102 static int pipe_kqfilter (struct file *fp, struct knote *kn);
103 static int pipe_stat (struct file *fp, struct stat *sb, struct ucred *cred);
104 static int pipe_ioctl (struct file *fp, u_long cmd, caddr_t data, struct ucred *cred);
105
106 static struct fileops pipeops = {
107 .fo_read = pipe_read,
108 .fo_write = pipe_write,
109 .fo_ioctl = pipe_ioctl,
110 .fo_poll = pipe_poll,
111 .fo_kqfilter = pipe_kqfilter,
112 .fo_stat = pipe_stat,
113 .fo_close = pipe_close,
114 .fo_shutdown = pipe_shutdown
115 };
116
117 static void filt_pipedetach(struct knote *kn);
118 static int filt_piperead(struct knote *kn, long hint);
119 static int filt_pipewrite(struct knote *kn, long hint);
120
121 static struct filterops pipe_rfiltops =
122 { 1, NULL, filt_pipedetach, filt_piperead };
123 static struct filterops pipe_wfiltops =
124 { 1, NULL, filt_pipedetach, filt_pipewrite };
125
126 MALLOC_DEFINE(M_PIPE, "pipe", "pipe structures");
127
128 /*
129 * Default pipe buffer size(s), this can be kind-of large now because pipe
130 * space is pageable. The pipe code will try to maintain locality of
131 * reference for performance reasons, so small amounts of outstanding I/O
132 * will not wipe the cache.
133 */
134 #define MINPIPESIZE (PIPE_SIZE/3)
135 #define MAXPIPESIZE (2*PIPE_SIZE/3)
136
137 /*
138 * Maximum amount of kva for pipes -- this is kind-of a soft limit, but
139 * is there so that on large systems, we don't exhaust it.
140 */
141 #define MAXPIPEKVA (8*1024*1024)
142
143 /*
144 * Limit for direct transfers, we cannot, of course limit
145 * the amount of kva for pipes in general though.
146 */
147 #define LIMITPIPEKVA (16*1024*1024)
148
149 /*
150 * Limit the number of "big" pipes
151 */
152 #define LIMITBIGPIPES 32
153 #define PIPEQ_MAX_CACHE 16 /* per-cpu pipe structure cache */
154
155 static int pipe_maxbig = LIMITBIGPIPES;
156 static int pipe_maxcache = PIPEQ_MAX_CACHE;
157 static int pipe_bigcount;
158 static int pipe_nbig;
159 static int pipe_bcache_alloc;
160 static int pipe_bkmem_alloc;
161 /*
162 * There's a bug in the sfbuf-based direct write code, not yet located.
163 * Disable it for now.
164 */
165 static int pipe_dwrite_enable = 0; /* 0:copy, 1:kmem/sfbuf 2:force */
166 static int pipe_dwrite_sfbuf = 1; /* 0:kmem_map 1:sfbufs 2:sfbufs_dmap */
167 /* 3:sfbuf_dmap w/ forced invlpg */
168
169 SYSCTL_NODE(_kern, OID_AUTO, pipe, CTLFLAG_RW, 0, "Pipe operation");
170 SYSCTL_INT(_kern_pipe, OID_AUTO, nbig,
171 CTLFLAG_RD, &pipe_nbig, 0, "numer of big pipes allocated");
172 SYSCTL_INT(_kern_pipe, OID_AUTO, bigcount,
173 CTLFLAG_RW, &pipe_bigcount, 0, "number of times pipe expanded");
174 SYSCTL_INT(_kern_pipe, OID_AUTO, maxcache,
175 CTLFLAG_RW, &pipe_maxcache, 0, "max pipes cached per-cpu");
176 SYSCTL_INT(_kern_pipe, OID_AUTO, maxbig,
177 CTLFLAG_RW, &pipe_maxbig, 0, "max number of big pipes");
178 SYSCTL_INT(_kern_pipe, OID_AUTO, dwrite_enable,
179 CTLFLAG_RW, &pipe_dwrite_enable, 0, "1:enable/2:force direct writes");
180 SYSCTL_INT(_kern_pipe, OID_AUTO, dwrite_sfbuf,
181 CTLFLAG_RW, &pipe_dwrite_sfbuf, 0,
182 "(if dwrite_enable) 0:kmem 1:sfbuf 2:sfbuf_dmap 3:sfbuf_dmap_forceinvlpg");
183 #if !defined(NO_PIPE_SYSCTL_STATS)
184 SYSCTL_INT(_kern_pipe, OID_AUTO, bcache_alloc,
185 CTLFLAG_RW, &pipe_bcache_alloc, 0, "pipe buffer from pcpu cache");
186 SYSCTL_INT(_kern_pipe, OID_AUTO, bkmem_alloc,
187 CTLFLAG_RW, &pipe_bkmem_alloc, 0, "pipe buffer from kmem");
188 #endif
189
190 static void pipeclose (struct pipe *cpipe);
191 static void pipe_free_kmem (struct pipe *cpipe);
192 static int pipe_create (struct pipe **cpipep);
193 static __inline int pipelock (struct pipe *cpipe, int catch);
194 static __inline void pipeunlock (struct pipe *cpipe);
195 static __inline void pipeselwakeup (struct pipe *cpipe);
196 #ifndef PIPE_NODIRECT
197 static int pipe_build_write_buffer (struct pipe *wpipe, struct uio *uio);
198 static int pipe_direct_write (struct pipe *wpipe, struct uio *uio);
199 static void pipe_clone_write_buffer (struct pipe *wpipe);
200 #endif
201 static int pipespace (struct pipe *cpipe, int size);
202
203 /*
204 * The pipe system call for the DTYPE_PIPE type of pipes
205 *
206 * pipe_ARgs(int dummy)
207 */
208
209 /* ARGSUSED */
210 int
211 sys_pipe(struct pipe_args *uap)
212 {
213 struct thread *td = curthread;
214 struct proc *p = td->td_proc;
215 struct file *rf, *wf;
216 struct pipe *rpipe, *wpipe;
217 int fd1, fd2, error;
218
219 KKASSERT(p);
220
221 rpipe = wpipe = NULL;
222 if (pipe_create(&rpipe) || pipe_create(&wpipe)) {
223 pipeclose(rpipe);
224 pipeclose(wpipe);
225 return (ENFILE);
226 }
227
228 rpipe->pipe_state |= PIPE_DIRECTOK;
229 wpipe->pipe_state |= PIPE_DIRECTOK;
230
231 /*
232 * Select the direct-map features to use for this pipe. Since the
233 * sysctl's can change on the fly we record the settings when the
234 * pipe is created.
235 *
236 * Generally speaking the system will default to what we consider
237 * to be the best-balanced and most stable option. Right now this
238 * is SFBUF1. Modes 2 and 3 are considered experiemental at the
239 * moment.
240 */
241 wpipe->pipe_feature = PIPE_COPY;
242 if (pipe_dwrite_enable) {
243 switch(pipe_dwrite_sfbuf) {
244 case 0:
245 wpipe->pipe_feature = PIPE_KMEM;
246 break;
247 case 1:
248 wpipe->pipe_feature = PIPE_SFBUF1;
249 break;
250 case 2:
251 case 3:
252 wpipe->pipe_feature = PIPE_SFBUF2;
253 break;
254 }
255 }
256 rpipe->pipe_feature = wpipe->pipe_feature;
257
258 error = falloc(p, &rf, &fd1);
259 if (error) {
260 pipeclose(rpipe);
261 pipeclose(wpipe);
262 return (error);
263 }
264 uap->sysmsg_fds[0] = fd1;
265
266 /*
267 * Warning: once we've gotten past allocation of the fd for the
268 * read-side, we can only drop the read side via fdrop() in order
269 * to avoid races against processes which manage to dup() the read
270 * side while we are blocked trying to allocate the write side.
271 */
272 rf->f_type = DTYPE_PIPE;
273 rf->f_flag = FREAD | FWRITE;
274 rf->f_ops = &pipeops;
275 rf->f_data = rpipe;
276 error = falloc(p, &wf, &fd2);
277 if (error) {
278 fsetfd(p, NULL, fd1);
279 fdrop(rf);
280 /* rpipe has been closed by fdrop(). */
281 pipeclose(wpipe);
282 return (error);
283 }
284 wf->f_type = DTYPE_PIPE;
285 wf->f_flag = FREAD | FWRITE;
286 wf->f_ops = &pipeops;
287 wf->f_data = wpipe;
288 uap->sysmsg_fds[1] = fd2;
289
290 rpipe->pipe_peer = wpipe;
291 wpipe->pipe_peer = rpipe;
292
293 fsetfd(p, rf, fd1);
294 fsetfd(p, wf, fd2);
295 fdrop(rf);
296 fdrop(wf);
297
298 return (0);
299 }
300
301 /*
302 * Allocate kva for pipe circular buffer, the space is pageable
303 * This routine will 'realloc' the size of a pipe safely, if it fails
304 * it will retain the old buffer.
305 * If it fails it will return ENOMEM.
306 */
307 static int
308 pipespace(struct pipe *cpipe, int size)
309 {
310 struct vm_object *object;
311 caddr_t buffer;
312 int npages, error;
313
314 npages = round_page(size) / PAGE_SIZE;
315 object = cpipe->pipe_buffer.object;
316
317 /*
318 * [re]create the object if necessary and reserve space for it
319 * in the kernel_map. The object and memory are pageable. On
320 * success, free the old resources before assigning the new
321 * ones.
322 */
323 if (object == NULL || object->size != npages) {
324 object = vm_object_allocate(OBJT_DEFAULT, npages);
325 buffer = (caddr_t)vm_map_min(&kernel_map);
326
327 error = vm_map_find(&kernel_map, object, 0,
328 (vm_offset_t *)&buffer, size,
329 1,
330 VM_MAPTYPE_NORMAL,
331 VM_PROT_ALL, VM_PROT_ALL,
332 0);
333
334 if (error != KERN_SUCCESS) {
335 vm_object_deallocate(object);
336 return (ENOMEM);
337 }
338 pipe_free_kmem(cpipe);
339 cpipe->pipe_buffer.object = object;
340 cpipe->pipe_buffer.buffer = buffer;
341 cpipe->pipe_buffer.size = size;
342 ++pipe_bkmem_alloc;
343 } else {
344 ++pipe_bcache_alloc;
345 }
346 cpipe->pipe_buffer.in = 0;
347 cpipe->pipe_buffer.out = 0;
348 cpipe->pipe_buffer.cnt = 0;
349 return (0);
350 }
351
352 /*
353 * Initialize and allocate VM and memory for pipe, pulling the pipe from
354 * our per-cpu cache if possible. For now make sure it is sized for the
355 * smaller PIPE_SIZE default.
356 */
357 static int
358 pipe_create(struct pipe **cpipep)
359 {
360 globaldata_t gd = mycpu;
361 struct pipe *cpipe;
362 int error;
363
364 if ((cpipe = gd->gd_pipeq) != NULL) {
365 gd->gd_pipeq = cpipe->pipe_peer;
366 --gd->gd_pipeqcount;
367 cpipe->pipe_peer = NULL;
368 } else {
369 cpipe = kmalloc(sizeof(struct pipe), M_PIPE, M_WAITOK|M_ZERO);
370 }
371 *cpipep = cpipe;
372 if ((error = pipespace(cpipe, PIPE_SIZE)) != 0)
373 return (error);
374 vfs_timestamp(&cpipe->pipe_ctime);
375 cpipe->pipe_atime = cpipe->pipe_ctime;
376 cpipe->pipe_mtime = cpipe->pipe_ctime;
377 return (0);
378 }
379
380
381 /*
382 * lock a pipe for I/O, blocking other access
383 */
384 static __inline int
385 pipelock(struct pipe *cpipe, int catch)
386 {
387 int error;
388
389 while (cpipe->pipe_state & PIPE_LOCK) {
390 cpipe->pipe_state |= PIPE_LWANT;
391 error = tsleep(cpipe, (catch ? PCATCH : 0), "pipelk", 0);
392 if (error != 0)
393 return (error);
394 }
395 cpipe->pipe_state |= PIPE_LOCK;
396 return (0);
397 }
398
399 /*
400 * unlock a pipe I/O lock
401 */
402 static __inline void
403 pipeunlock(struct pipe *cpipe)
404 {
405
406 cpipe->pipe_state &= ~PIPE_LOCK;
407 if (cpipe->pipe_state & PIPE_LWANT) {
408 cpipe->pipe_state &= ~PIPE_LWANT;
409 wakeup(cpipe);
410 }
411 }
412
413 static __inline void
414 pipeselwakeup(struct pipe *cpipe)
415 {
416
417 if (cpipe->pipe_state & PIPE_SEL) {
418 cpipe->pipe_state &= ~PIPE_SEL;
419 selwakeup(&cpipe->pipe_sel);
420 }
421 if ((cpipe->pipe_state & PIPE_ASYNC) && cpipe->pipe_sigio)
422 pgsigio(cpipe->pipe_sigio, SIGIO, 0);
423 KNOTE(&cpipe->pipe_sel.si_note, 0);
424 }
425
426 /*
427 * MPALMOSTSAFE (acquires mplock)
428 */
429 static int
430 pipe_read(struct file *fp, struct uio *uio, struct ucred *cred, int fflags)
431 {
432 struct pipe *rpipe;
433 int error;
434 int nread = 0;
435 int nbio;
436 u_int size;
437
438 get_mplock();
439 rpipe = (struct pipe *) fp->f_data;
440 ++rpipe->pipe_busy;
441 error = pipelock(rpipe, 1);
442 if (error)
443 goto unlocked_error;
444
445 if (fflags & O_FBLOCKING)
446 nbio = 0;
447 else if (fflags & O_FNONBLOCKING)
448 nbio = 1;
449 else if (fp->f_flag & O_NONBLOCK)
450 nbio = 1;
451 else
452 nbio = 0;
453
454 while (uio->uio_resid) {
455 caddr_t va;
456
457 if (rpipe->pipe_buffer.cnt > 0) {
458 /*
459 * normal pipe buffer receive
460 */
461 size = rpipe->pipe_buffer.size - rpipe->pipe_buffer.out;
462 if (size > rpipe->pipe_buffer.cnt)
463 size = rpipe->pipe_buffer.cnt;
464 if (size > (u_int) uio->uio_resid)
465 size = (u_int) uio->uio_resid;
466
467 error = uiomove(&rpipe->pipe_buffer.buffer
468 [rpipe->pipe_buffer.out],
469 size, uio);
470 if (error)
471 break;
472
473 rpipe->pipe_buffer.out += size;
474 if (rpipe->pipe_buffer.out >= rpipe->pipe_buffer.size)
475 rpipe->pipe_buffer.out = 0;
476
477 rpipe->pipe_buffer.cnt -= size;
478
479 /*
480 * If there is no more to read in the pipe, reset
481 * its pointers to the beginning. This improves
482 * cache hit stats.
483 */
484 if (rpipe->pipe_buffer.cnt == 0) {
485 rpipe->pipe_buffer.in = 0;
486 rpipe->pipe_buffer.out = 0;
487 }
488 nread += size;
489 #ifndef PIPE_NODIRECT
490 } else if (rpipe->pipe_kva &&
491 rpipe->pipe_feature == PIPE_KMEM &&
492 (rpipe->pipe_state & (PIPE_DIRECTW|PIPE_DIRECTIP))
493 == PIPE_DIRECTW
494 ) {
495 /*
496 * Direct copy using source-side kva mapping
497 */
498 size = rpipe->pipe_map.xio_bytes -
499 rpipe->pipe_buffer.out;
500 if (size > (u_int)uio->uio_resid)
501 size = (u_int)uio->uio_resid;
502 va = (caddr_t)rpipe->pipe_kva +
503 xio_kvaoffset(&rpipe->pipe_map, rpipe->pipe_buffer.out);
504 error = uiomove(va, size, uio);
505 if (error)
506 break;
507 nread += size;
508 rpipe->pipe_buffer.out += size;
509 if (rpipe->pipe_buffer.out == rpipe->pipe_map.xio_bytes) {
510 rpipe->pipe_state |= PIPE_DIRECTIP;
511 rpipe->pipe_state &= ~PIPE_DIRECTW;
512 /* reset out index for copy mode */
513 rpipe->pipe_buffer.out = 0;
514 wakeup(rpipe);
515 }
516 } else if (rpipe->pipe_buffer.out != rpipe->pipe_map.xio_bytes &&
517 rpipe->pipe_kva &&
518 rpipe->pipe_feature == PIPE_SFBUF2 &&
519 (rpipe->pipe_state & (PIPE_DIRECTW|PIPE_DIRECTIP))
520 == PIPE_DIRECTW
521 ) {
522 /*
523 * Direct copy, bypassing a kernel buffer. We cannot
524 * mess with the direct-write buffer until
525 * PIPE_DIRECTIP is cleared. In order to prevent
526 * the pipe_write code from racing itself in
527 * direct_write, we set DIRECTIP when we clear
528 * DIRECTW after we have exhausted the buffer.
529 */
530 if (pipe_dwrite_sfbuf == 3)
531 rpipe->pipe_kvamask = 0;
532 pmap_qenter2(rpipe->pipe_kva, rpipe->pipe_map.xio_pages,
533 rpipe->pipe_map.xio_npages,
534 &rpipe->pipe_kvamask);
535 size = rpipe->pipe_map.xio_bytes -
536 rpipe->pipe_buffer.out;
537 if (size > (u_int)uio->uio_resid)
538 size = (u_int)uio->uio_resid;
539 va = (caddr_t)rpipe->pipe_kva + xio_kvaoffset(&rpipe->pipe_map, rpipe->pipe_buffer.out);
540 error = uiomove(va, size, uio);
541 if (error)
542 break;
543 nread += size;
544 rpipe->pipe_buffer.out += size;
545 if (rpipe->pipe_buffer.out == rpipe->pipe_map.xio_bytes) {
546 rpipe->pipe_state |= PIPE_DIRECTIP;
547 rpipe->pipe_state &= ~PIPE_DIRECTW;
548 /* reset out index for copy mode */
549 rpipe->pipe_buffer.out = 0;
550 wakeup(rpipe);
551 }
552 } else if (rpipe->pipe_buffer.out != rpipe->pipe_map.xio_bytes &&
553 rpipe->pipe_feature == PIPE_SFBUF1 &&
554 (rpipe->pipe_state & (PIPE_DIRECTW|PIPE_DIRECTIP))
555 == PIPE_DIRECTW
556 ) {
557 /*
558 * Direct copy, bypassing a kernel buffer. We cannot
559 * mess with the direct-write buffer until
560 * PIPE_DIRECTIP is cleared. In order to prevent
561 * the pipe_write code from racing itself in
562 * direct_write, we set DIRECTIP when we clear
563 * DIRECTW after we have exhausted the buffer.
564 */
565 error = xio_uio_copy(&rpipe->pipe_map, rpipe->pipe_buffer.out, uio, &size);
566 if (error)
567 break;
568 nread += size;
569 rpipe->pipe_buffer.out += size;
570 if (rpipe->pipe_buffer.out == rpipe->pipe_map.xio_bytes) {
571 rpipe->pipe_state |= PIPE_DIRECTIP;
572 rpipe->pipe_state &= ~PIPE_DIRECTW;
573 /* reset out index for copy mode */
574 rpipe->pipe_buffer.out = 0;
575 wakeup(rpipe);
576 }
577 #endif
578 } else {
579 /*
580 * detect EOF condition
581 * read returns 0 on EOF, no need to set error
582 */
583 if (rpipe->pipe_state & PIPE_EOF)
584 break;
585
586 /*
587 * If the "write-side" has been blocked, wake it up now.
588 */
589 if (rpipe->pipe_state & PIPE_WANTW) {
590 rpipe->pipe_state &= ~PIPE_WANTW;
591 wakeup(rpipe);
592 }
593
594 /*
595 * Break if some data was read.
596 */
597 if (nread > 0)
598 break;
599
600 /*
601 * Unlock the pipe buffer for our remaining
602 * processing. We will either break out with an
603 * error or we will sleep and relock to loop.
604 */
605 pipeunlock(rpipe);
606
607 /*
608 * Handle non-blocking mode operation or
609 * wait for more data.
610 */
611 if (nbio) {
612 error = EAGAIN;
613 } else {
614 rpipe->pipe_state |= PIPE_WANTR;
615 if ((error = tsleep(rpipe, PCATCH,
616 "piperd", 0)) == 0) {
617 error = pipelock(rpipe, 1);
618 }
619 }
620 if (error)
621 goto unlocked_error;
622 }
623 }
624 pipeunlock(rpipe);
625
626 if (error == 0)
627 vfs_timestamp(&rpipe->pipe_atime);
628 unlocked_error:
629 --rpipe->pipe_busy;
630
631 /*
632 * PIPE_WANT processing only makes sense if pipe_busy is 0.
633 */
634 if ((rpipe->pipe_busy == 0) && (rpipe->pipe_state & PIPE_WANT)) {
635 rpipe->pipe_state &= ~(PIPE_WANT|PIPE_WANTW);
636 wakeup(rpipe);
637 } else if (rpipe->pipe_buffer.cnt < MINPIPESIZE) {
638 /*
639 * Handle write blocking hysteresis.
640 */
641 if (rpipe->pipe_state & PIPE_WANTW) {
642 rpipe->pipe_state &= ~PIPE_WANTW;
643 wakeup(rpipe);
644 }
645 }
646
647 if ((rpipe->pipe_buffer.size - rpipe->pipe_buffer.cnt) >= PIPE_BUF)
648 pipeselwakeup(rpipe);
649 rel_mplock();
650 return (error);
651 }
652
653 #ifndef PIPE_NODIRECT
654 /*
655 * Map the sending processes' buffer into kernel space and wire it.
656 * This is similar to a physical write operation.
657 */
658 static int
659 pipe_build_write_buffer(struct pipe *wpipe, struct uio *uio)
660 {
661 int error;
662 u_int size;
663
664 size = (u_int) uio->uio_iov->iov_len;
665 if (size > wpipe->pipe_buffer.size)
666 size = wpipe->pipe_buffer.size;
667
668 if (uio->uio_segflg == UIO_SYSSPACE) {
669 error = xio_init_kbuf(&wpipe->pipe_map, uio->uio_iov->iov_base,
670 size);
671 } else {
672 error = xio_init_ubuf(&wpipe->pipe_map, uio->uio_iov->iov_base,
673 size, XIOF_READ);
674 }
675 wpipe->pipe_buffer.out = 0;
676 if (error)
677 return(error);
678
679 /*
680 * Create a kernel map for KMEM and SFBUF2 copy modes. SFBUF2 will
681 * map the pages on the target while KMEM maps the pages now.
682 */
683 switch(wpipe->pipe_feature) {
684 case PIPE_KMEM:
685 case PIPE_SFBUF2:
686 if (wpipe->pipe_kva == 0) {
687 wpipe->pipe_kva =
688 kmem_alloc_nofault(&kernel_map, XIO_INTERNAL_SIZE);
689 wpipe->pipe_kvamask = 0;
690 }
691 if (wpipe->pipe_feature == PIPE_KMEM) {
692 pmap_qenter(wpipe->pipe_kva, wpipe->pipe_map.xio_pages,
693 wpipe->pipe_map.xio_npages);
694 }
695 break;
696 default:
697 break;
698 }
699
700 /*
701 * And update the uio data. The XIO might have loaded fewer bytes
702 * then requested so reload 'size'.
703 */
704 size = wpipe->pipe_map.xio_bytes;
705 uio->uio_iov->iov_len -= size;
706 uio->uio_iov->iov_base = (char *)uio->uio_iov->iov_base + size;
707 if (uio->uio_iov->iov_len == 0)
708 uio->uio_iov++;
709 uio->uio_resid -= size;
710 uio->uio_offset += size;
711 return (0);
712 }
713
714 /*
715 * In the case of a signal, the writing process might go away. This
716 * code copies the data into the circular buffer so that the source
717 * pages can be freed without loss of data.
718 *
719 * Note that in direct mode pipe_buffer.out is used to track the
720 * XIO offset. We are converting the direct mode into buffered mode
721 * which changes the meaning of pipe_buffer.out.
722 */
723 static void
724 pipe_clone_write_buffer(struct pipe *wpipe)
725 {
726 int size;
727 int offset;
728
729 offset = wpipe->pipe_buffer.out;
730 size = wpipe->pipe_map.xio_bytes - offset;
731
732 KKASSERT(size <= wpipe->pipe_buffer.size);
733
734 wpipe->pipe_buffer.in = size;
735 wpipe->pipe_buffer.out = 0;
736 wpipe->pipe_buffer.cnt = size;
737 wpipe->pipe_state &= ~(PIPE_DIRECTW | PIPE_DIRECTIP);
738
739 xio_copy_xtok(&wpipe->pipe_map, offset, wpipe->pipe_buffer.buffer, size);
740 xio_release(&wpipe->pipe_map);
741 if (wpipe->pipe_kva) {
742 pmap_qremove(wpipe->pipe_kva, XIO_INTERNAL_PAGES);
743 kmem_free(&kernel_map, wpipe->pipe_kva, XIO_INTERNAL_SIZE);
744 wpipe->pipe_kva = 0;
745 }
746 }
747
748 /*
749 * This implements the pipe buffer write mechanism. Note that only
750 * a direct write OR a normal pipe write can be pending at any given time.
751 * If there are any characters in the pipe buffer, the direct write will
752 * be deferred until the receiving process grabs all of the bytes from
753 * the pipe buffer. Then the direct mapping write is set-up.
754 */
755 static int
756 pipe_direct_write(struct pipe *wpipe, struct uio *uio)
757 {
758 int error;
759
760 retry:
761 while (wpipe->pipe_state & (PIPE_DIRECTW|PIPE_DIRECTIP)) {
762 if (wpipe->pipe_state & PIPE_WANTR) {
763 wpipe->pipe_state &= ~PIPE_WANTR;
764 wakeup(wpipe);
765 }
766 wpipe->pipe_state |= PIPE_WANTW;
767 error = tsleep(wpipe, PCATCH, "pipdww", 0);
768 if (error)
769 goto error2;
770 if (wpipe->pipe_state & PIPE_EOF) {
771 error = EPIPE;
772 goto error2;
773 }
774 }
775 KKASSERT(wpipe->pipe_map.xio_bytes == 0);
776 if (wpipe->pipe_buffer.cnt > 0) {
777 if (wpipe->pipe_state & PIPE_WANTR) {
778 wpipe->pipe_state &= ~PIPE_WANTR;
779 wakeup(wpipe);
780 }
781
782 wpipe->pipe_state |= PIPE_WANTW;
783 error = tsleep(wpipe, PCATCH, "pipdwc", 0);
784 if (error)
785 goto error2;
786 if (wpipe->pipe_state & PIPE_EOF) {
787 error = EPIPE;
788 goto error2;
789 }
790 goto retry;
791 }
792
793 /*
794 * Build our direct-write buffer
795 */
796 wpipe->pipe_state |= PIPE_DIRECTW | PIPE_DIRECTIP;
797 error = pipe_build_write_buffer(wpipe, uio);
798 if (error)
799 goto error1;
800 wpipe->pipe_state &= ~PIPE_DIRECTIP;
801
802 /*
803 * Wait until the receiver has snarfed the data. Since we are likely
804 * going to sleep we optimize the case and yield synchronously,
805 * possibly avoiding the tsleep().
806 */
807 error = 0;
808 while (!error && (wpipe->pipe_state & PIPE_DIRECTW)) {
809 if (wpipe->pipe_state & PIPE_EOF) {
810 pipelock(wpipe, 0);
811 xio_release(&wpipe->pipe_map);
812 if (wpipe->pipe_kva) {
813 pmap_qremove(wpipe->pipe_kva, XIO_INTERNAL_PAGES);
814 kmem_free(&kernel_map, wpipe->pipe_kva, XIO_INTERNAL_SIZE);
815 wpipe->pipe_kva = 0;
816 }
817 pipeunlock(wpipe);
818 pipeselwakeup(wpipe);
819 error = EPIPE;
820 goto error1;
821 }
822 if (wpipe->pipe_state & PIPE_WANTR) {
823 wpipe->pipe_state &= ~PIPE_WANTR;
824 wakeup(wpipe);
825 }
826 pipeselwakeup(wpipe);
827 error = tsleep(wpipe, PCATCH, "pipdwt", 0);
828 }
829 pipelock(wpipe,0);
830 if (wpipe->pipe_state & PIPE_DIRECTW) {
831 /*
832 * this bit of trickery substitutes a kernel buffer for
833 * the process that might be going away.
834 */
835 pipe_clone_write_buffer(wpipe);
836 KKASSERT((wpipe->pipe_state & PIPE_DIRECTIP) == 0);
837 } else {
838 /*
839 * note: The pipe_kva mapping is not qremove'd here. For
840 * legacy PIPE_KMEM mode this constitutes an improvement
841 * over the original FreeBSD-4 algorithm. For PIPE_SFBUF2
842 * mode the kva mapping must not be removed to get the
843 * caching benefit.
844 *
845 * For testing purposes we will give the original algorithm
846 * the benefit of the doubt 'what it could have been', and
847 * keep the optimization.
848 */
849 KKASSERT(wpipe->pipe_state & PIPE_DIRECTIP);
850 xio_release(&wpipe->pipe_map);
851 wpipe->pipe_state &= ~PIPE_DIRECTIP;
852 }
853 pipeunlock(wpipe);
854 return (error);
855
856 /*
857 * Direct-write error, clear the direct write flags.
858 */
859 error1:
860 wpipe->pipe_state &= ~(PIPE_DIRECTW | PIPE_DIRECTIP);
861 /* fallthrough */
862
863 /*
864 * General error, wakeup the other side if it happens to be sleeping.
865 */
866 error2:
867 wakeup(wpipe);
868 return (error);
869 }
870 #endif
871
872 /*
873 * MPALMOSTSAFE - acquires mplock
874 */
875 static int
876 pipe_write(struct file *fp, struct uio *uio, struct ucred *cred, int fflags)
877 {
878 int error = 0;
879 int orig_resid;
880 int nbio;
881 struct pipe *wpipe, *rpipe;
882
883 get_mplock();
884 rpipe = (struct pipe *) fp->f_data;
885 wpipe = rpipe->pipe_peer;
886
887 /*
888 * detect loss of pipe read side, issue SIGPIPE if lost.
889 */
890 if ((wpipe == NULL) || (wpipe->pipe_state & PIPE_EOF)) {
891 rel_mplock();
892 return (EPIPE);
893 }
894 ++wpipe->pipe_busy;
895
896 if (fflags & O_FBLOCKING)
897 nbio = 0;
898 else if (fflags & O_FNONBLOCKING)
899 nbio = 1;
900 else if (fp->f_flag & O_NONBLOCK)
901 nbio = 1;
902 else
903 nbio = 0;
904
905 /*
906 * If it is advantageous to resize the pipe buffer, do
907 * so.
908 */
909 if ((uio->uio_resid > PIPE_SIZE) &&
910 (pipe_nbig < pipe_maxbig) &&
911 (wpipe->pipe_state & (PIPE_DIRECTW|PIPE_DIRECTIP)) == 0 &&
912 (wpipe->pipe_buffer.size <= PIPE_SIZE) &&
913 (wpipe->pipe_buffer.cnt == 0) &&
914 (error = pipelock(wpipe, 1)) == 0) {
915 /*
916 * Recheck after lock.
917 */
918 if ((pipe_nbig < pipe_maxbig) &&
919 (wpipe->pipe_state & (PIPE_DIRECTW|PIPE_DIRECTIP)) == 0 &&
920 (wpipe->pipe_buffer.size <= PIPE_SIZE) &&
921 (wpipe->pipe_buffer.cnt == 0)) {
922 if (pipespace(wpipe, BIG_PIPE_SIZE) == 0) {
923 ++pipe_bigcount;
924 pipe_nbig++;
925 }
926 }
927 pipeunlock(wpipe);
928 }
929
930 /*
931 * If an early error occured unbusy and return, waking up any pending
932 * readers.
933 */
934 if (error) {
935 --wpipe->pipe_busy;
936 if ((wpipe->pipe_busy == 0) &&
937 (wpipe->pipe_state & PIPE_WANT)) {
938 wpipe->pipe_state &= ~(PIPE_WANT | PIPE_WANTR);
939 wakeup(wpipe);
940 }
941 rel_mplock();
942 return(error);
943 }
944
945 KASSERT(wpipe->pipe_buffer.buffer != NULL, ("pipe buffer gone"));
946
947 orig_resid = uio->uio_resid;
948
949 while (uio->uio_resid) {
950 int space;
951
952 #ifndef PIPE_NODIRECT
953 /*
954 * If direct process-to-process writes are enabled and
955 * the buffer is large enough, and this is blocking IO,
956 * then use the direct write feature.
957 *
958 * If the pipe was opened at a time when the direct write
959 * feature was not enabled pipe_feature will be set to
960 * PIPE_COPY and we do not use the feature.
961 *
962 * The direct write mechanism will detect the reader going
963 * away on us.
964 */
965 if ((uio->uio_iov->iov_len >= PIPE_MINDIRECT ||
966 pipe_dwrite_enable > 1) &&
967 nbio == 0 && pipe_dwrite_enable &&
968 wpipe->pipe_feature != PIPE_COPY
969 ) {
970 error = pipe_direct_write( wpipe, uio);
971 if (error)
972 break;
973 continue;
974 }
975 #endif
976
977 /*
978 * Pipe buffered writes cannot be coincidental with
979 * direct writes. We wait until the currently executing
980 * direct write is completed before we start filling the
981 * pipe buffer. We break out if a signal occurs or the
982 * reader goes away.
983 */
984 retrywrite:
985 while (wpipe->pipe_state & (PIPE_DIRECTW|PIPE_DIRECTIP)) {
986 if (wpipe->pipe_state & PIPE_WANTR) {
987 wpipe->pipe_state &= ~PIPE_WANTR;
988 wakeup(wpipe);
989 }
990 error = tsleep(wpipe, PCATCH, "pipbww", 0);
991 if (wpipe->pipe_state & PIPE_EOF)
992 break;
993 if (error)
994 break;
995 }
996 if (wpipe->pipe_state & PIPE_EOF) {
997 error = EPIPE;
998 break;
999 }
1000
1001 space = wpipe->pipe_buffer.size - wpipe->pipe_buffer.cnt;
1002
1003 /* Writes of size <= PIPE_BUF must be atomic. */
1004 if ((space < uio->uio_resid) && (orig_resid <= PIPE_BUF))
1005 space = 0;
1006
1007 /*
1008 * Write to fill, read size handles write hysteresis. Also
1009 * additional restrictions can cause select-based non-blocking
1010 * writes to spin.
1011 */
1012 if (space > 0) {
1013 if ((error = pipelock(wpipe,1)) == 0) {
1014 int size; /* Transfer size */
1015 int segsize; /* first segment to transfer */
1016
1017 /*
1018 * It is possible for a direct write to
1019 * slip in on us... handle it here...
1020 */
1021 if (wpipe->pipe_state & (PIPE_DIRECTW|PIPE_DIRECTIP)) {
1022 pipeunlock(wpipe);
1023 goto retrywrite;
1024 }
1025 /*
1026 * If a process blocked in uiomove, our
1027 * value for space might be bad.
1028 *
1029 * XXX will we be ok if the reader has gone
1030 * away here?
1031 */
1032 if (space > wpipe->pipe_buffer.size -
1033 wpipe->pipe_buffer.cnt) {
1034 pipeunlock(wpipe);
1035 goto retrywrite;
1036 }
1037
1038 /*
1039 * Transfer size is minimum of uio transfer
1040 * and free space in pipe buffer.
1041 */
1042 if (space > uio->uio_resid)
1043 size = uio->uio_resid;
1044 else
1045 size = space;
1046 /*
1047 * First segment to transfer is minimum of
1048 * transfer size and contiguous space in
1049 * pipe buffer. If first segment to transfer
1050 * is less than the transfer size, we've got
1051 * a wraparound in the buffer.
1052 */
1053 segsize = wpipe->pipe_buffer.size -
1054 wpipe->pipe_buffer.in;
1055 if (segsize > size)
1056 segsize = size;
1057
1058 /* Transfer first segment */
1059
1060 error = uiomove(&wpipe->pipe_buffer.buffer
1061 [wpipe->pipe_buffer.in],
1062 segsize, uio);
1063
1064 if (error == 0 && segsize < size) {
1065 /*
1066 * Transfer remaining part now, to
1067 * support atomic writes. Wraparound
1068 * happened.
1069 */
1070 if (wpipe->pipe_buffer.in + segsize !=
1071 wpipe->pipe_buffer.size)
1072 panic("Expected pipe buffer wraparound disappeared");
1073
1074 error = uiomove(&wpipe->pipe_buffer.
1075 buffer[0],
1076 size - segsize, uio);
1077 }
1078 if (error == 0) {
1079 wpipe->pipe_buffer.in += size;
1080 if (wpipe->pipe_buffer.in >=
1081 wpipe->pipe_buffer.size) {
1082 if (wpipe->pipe_buffer.in != size - segsize + wpipe->pipe_buffer.size)
1083 panic("Expected wraparound bad");
1084 wpipe->pipe_buffer.in = size - segsize;
1085 }
1086
1087 wpipe->pipe_buffer.cnt += size;
1088 if (wpipe->pipe_buffer.cnt > wpipe->pipe_buffer.size)
1089 panic("Pipe buffer overflow");
1090
1091 }
1092 pipeunlock(wpipe);
1093 }
1094 if (error)
1095 break;
1096
1097 } else {
1098 /*
1099 * If the "read-side" has been blocked, wake it up now
1100 * and yield to let it drain synchronously rather
1101 * then block.
1102 */
1103 if (wpipe->pipe_state & PIPE_WANTR) {
1104 wpipe->pipe_state &= ~PIPE_WANTR;
1105 wakeup(wpipe);
1106 }
1107
1108 /*
1109 * don't block on non-blocking I/O
1110 */
1111 if (nbio) {
1112 error = EAGAIN;
1113 break;
1114 }
1115
1116 /*
1117 * We have no more space and have something to offer,
1118 * wake up select/poll.
1119 */
1120 pipeselwakeup(wpipe);
1121
1122 wpipe->pipe_state |= PIPE_WANTW;
1123 error = tsleep(wpipe, PCATCH, "pipewr", 0);
1124 if (error != 0)
1125 break;
1126 /*
1127 * If read side wants to go away, we just issue a signal
1128 * to ourselves.
1129 */
1130 if (wpipe->pipe_state & PIPE_EOF) {
1131 error = EPIPE;
1132 break;
1133 }
1134 }
1135 }
1136
1137 --wpipe->pipe_busy;
1138
1139 if ((wpipe->pipe_busy == 0) && (wpipe->pipe_state & PIPE_WANT)) {
1140 wpipe->pipe_state &= ~(PIPE_WANT | PIPE_WANTR);
1141 wakeup(wpipe);
1142 } else if (wpipe->pipe_buffer.cnt > 0) {
1143 /*
1144 * If we have put any characters in the buffer, we wake up
1145 * the reader.
1146 */
1147 if (wpipe->pipe_state & PIPE_WANTR) {
1148 wpipe->pipe_state &= ~PIPE_WANTR;
1149 wakeup(wpipe);
1150 }
1151 }
1152
1153 /*
1154 * Don't return EPIPE if I/O was successful
1155 */
1156 if ((wpipe->pipe_buffer.cnt == 0) &&
1157 (uio->uio_resid == 0) &&
1158 (error == EPIPE)) {
1159 error = 0;
1160 }
1161
1162 if (error == 0)
1163 vfs_timestamp(&wpipe->pipe_mtime);
1164
1165 /*
1166 * We have something to offer,
1167 * wake up select/poll.
1168 */
1169 if (wpipe->pipe_buffer.cnt)
1170 pipeselwakeup(wpipe);
1171 rel_mplock();
1172 return (error);
1173 }
1174
1175 /*
1176 * MPALMOSTSAFE - acquires mplock
1177 *
1178 * we implement a very minimal set of ioctls for compatibility with sockets.
1179 */
1180 int
1181 pipe_ioctl(struct file *fp, u_long cmd, caddr_t data, struct ucred *cred)
1182 {
1183 struct pipe *mpipe;
1184 int error;
1185
1186 get_mplock();
1187 mpipe = (struct pipe *)fp->f_data;
1188
1189 switch (cmd) {
1190 case FIOASYNC:
1191 if (*(int *)data) {
1192 mpipe->pipe_state |= PIPE_ASYNC;
1193 } else {
1194 mpipe->pipe_state &= ~PIPE_ASYNC;
1195 }
1196 error = 0;
1197 break;
1198 case FIONREAD:
1199 if (mpipe->pipe_state & PIPE_DIRECTW) {
1200 *(int *)data = mpipe->pipe_map.xio_bytes -
1201 mpipe->pipe_buffer.out;
1202 } else {
1203 *(int *)data = mpipe->pipe_buffer.cnt;
1204 }
1205 error = 0;
1206 break;
1207 case FIOSETOWN:
1208 error = fsetown(*(int *)data, &mpipe->pipe_sigio);
1209 break;
1210 case FIOGETOWN:
1211 *(int *)data = fgetown(mpipe->pipe_sigio);
1212 error = 0;
1213 break;
1214 case TIOCSPGRP:
1215 /* This is deprecated, FIOSETOWN should be used instead. */
1216 error = fsetown(-(*(int *)data), &mpipe->pipe_sigio);
1217 break;
1218
1219 case TIOCGPGRP:
1220 /* This is deprecated, FIOGETOWN should be used instead. */
1221 *(int *)data = -fgetown(mpipe->pipe_sigio);
1222 error = 0;
1223 break;
1224 default:
1225 error = ENOTTY;
1226 break;
1227 }
1228 rel_mplock();
1229 return (error);
1230 }
1231
1232 /*
1233 * MPALMOSTSAFE - acquires mplock
1234 */
1235 int
1236 pipe_poll(struct file *fp, int events, struct ucred *cred)
1237 {
1238 struct pipe *rpipe;
1239 struct pipe *wpipe;
1240 int revents = 0;
1241
1242 get_mplock();
1243 rpipe = (struct pipe *)fp->f_data;
1244 wpipe = rpipe->pipe_peer;
1245 if (events & (POLLIN | POLLRDNORM))
1246 if ((rpipe->pipe_state & PIPE_DIRECTW) ||
1247 (rpipe->pipe_buffer.cnt > 0) ||
1248 (rpipe->pipe_state & PIPE_EOF))
1249 revents |= events & (POLLIN | POLLRDNORM);
1250
1251 if (events & (POLLOUT | POLLWRNORM))
1252 if (wpipe == NULL || (wpipe->pipe_state & PIPE_EOF) ||
1253 (((wpipe->pipe_state & PIPE_DIRECTW) == 0) &&
1254 (wpipe->pipe_buffer.size - wpipe->pipe_buffer.cnt) >= PIPE_BUF))
1255 revents |= events & (POLLOUT | POLLWRNORM);
1256
1257 if ((rpipe->pipe_state & PIPE_EOF) ||
1258 (wpipe == NULL) ||
1259 (wpipe->pipe_state & PIPE_EOF))
1260 revents |= POLLHUP;
1261
1262 if (revents == 0) {
1263 if (events & (POLLIN | POLLRDNORM)) {
1264 selrecord(curthread, &rpipe->pipe_sel);
1265 rpipe->pipe_state |= PIPE_SEL;
1266 }
1267
1268 if (events & (POLLOUT | POLLWRNORM)) {
1269 selrecord(curthread, &wpipe->pipe_sel);
1270 wpipe->pipe_state |= PIPE_SEL;
1271 }
1272 }
1273 rel_mplock();
1274 return (revents);
1275 }
1276
1277 /*
1278 * MPALMOSTSAFE - acquires mplock
1279 */
1280 static int
1281 pipe_stat(struct file *fp, struct stat *ub, struct ucred *cred)
1282 {
1283 struct pipe *pipe;
1284
1285 get_mplock();
1286 pipe = (struct pipe *)fp->f_data;
1287
1288 bzero((caddr_t)ub, sizeof(*ub));
1289 ub->st_mode = S_IFIFO;
1290 ub->st_blksize = pipe->pipe_buffer.size;
1291 ub->st_size = pipe->pipe_buffer.cnt;
1292 if (ub->st_size == 0 && (pipe->pipe_state & PIPE_DIRECTW)) {
1293 ub->st_size = pipe->pipe_map.xio_bytes -
1294 pipe->pipe_buffer.out;
1295 }
1296 ub->st_blocks = (ub->st_size + ub->st_blksize - 1) / ub->st_blksize;
1297 ub->st_atimespec = pipe->pipe_atime;
1298 ub->st_mtimespec = pipe->pipe_mtime;
1299 ub->st_ctimespec = pipe->pipe_ctime;
1300 /*
1301 * Left as 0: st_dev, st_ino, st_nlink, st_uid, st_gid, st_rdev,
1302 * st_flags, st_gen.
1303 * XXX (st_dev, st_ino) should be unique.
1304 */
1305 rel_mplock();
1306 return (0);
1307 }
1308
1309 /*
1310 * MPALMOSTSAFE - acquires mplock
1311 */
1312 static int
1313 pipe_close(struct file *fp)
1314 {
1315 struct pipe *cpipe;
1316
1317 get_mplock();
1318 cpipe = (struct pipe *)fp->f_data;
1319 fp->f_ops = &badfileops;
1320 fp->f_data = NULL;
1321 funsetown(cpipe->pipe_sigio);
1322 pipeclose(cpipe);
1323 rel_mplock();
1324 return (0);
1325 }
1326
1327 /*
1328 * Shutdown one or both directions of a full-duplex pipe.
1329 *
1330 * MPALMOSTSAFE - acquires mplock
1331 */
1332 static int
1333 pipe_shutdown(struct file *fp, int how)
1334 {
1335 struct pipe *rpipe;
1336 struct pipe *wpipe;
1337 int error = EPIPE;
1338
1339 get_mplock();
1340 rpipe = (struct pipe *)fp->f_data;
1341
1342 switch(how) {
1343 case SHUT_RDWR:
1344 case SHUT_RD:
1345 if (rpipe) {
1346 rpipe->pipe_state |= PIPE_EOF;
1347 pipeselwakeup(rpipe);
1348 if (rpipe->pipe_busy)
1349 wakeup(rpipe);
1350 error = 0;
1351 }
1352 if (how == SHUT_RD)
1353 break;
1354 /* fall through */
1355 case SHUT_WR:
1356 if (rpipe && (wpipe = rpipe->pipe_peer) != NULL) {
1357 wpipe->pipe_state |= PIPE_EOF;
1358 pipeselwakeup(wpipe);
1359 if (wpipe->pipe_busy)
1360 wakeup(wpipe);
1361 error = 0;
1362 }
1363 }
1364 rel_mplock();
1365 return (error);
1366 }
1367
1368 static void
1369 pipe_free_kmem(struct pipe *cpipe)
1370 {
1371 if (cpipe->pipe_buffer.buffer != NULL) {
1372 if (cpipe->pipe_buffer.size > PIPE_SIZE)
1373 --pipe_nbig;
1374 kmem_free(&kernel_map,
1375 (vm_offset_t)cpipe->pipe_buffer.buffer,
1376 cpipe->pipe_buffer.size);
1377 cpipe->pipe_buffer.buffer = NULL;
1378 cpipe->pipe_buffer.object = NULL;
1379 }
1380 #ifndef PIPE_NODIRECT
1381 KKASSERT(cpipe->pipe_map.xio_bytes == 0 &&
1382 cpipe->pipe_map.xio_offset == 0 &&
1383 cpipe->pipe_map.xio_npages == 0);
1384 #endif
1385 }
1386
1387 /*
1388 * shutdown the pipe
1389 */
1390 static void
1391 pipeclose(struct pipe *cpipe)
1392 {
1393 globaldata_t gd;
1394 struct pipe *ppipe;
1395
1396 if (cpipe == NULL)
1397 return;
1398
1399 pipeselwakeup(cpipe);
1400
1401 /*
1402 * If the other side is blocked, wake it up saying that
1403 * we want to close it down.
1404 */
1405 while (cpipe->pipe_busy) {
1406 wakeup(cpipe);
1407 cpipe->pipe_state |= PIPE_WANT | PIPE_EOF;
1408 tsleep(cpipe, 0, "pipecl", 0);
1409 }
1410
1411 /*
1412 * Disconnect from peer
1413 */
1414 if ((ppipe = cpipe->pipe_peer) != NULL) {
1415 pipeselwakeup(ppipe);
1416
1417 ppipe->pipe_state |= PIPE_EOF;
1418 wakeup(ppipe);
1419 KNOTE(&ppipe->pipe_sel.si_note, 0);
1420 ppipe->pipe_peer = NULL;
1421 }
1422
1423 if (cpipe->pipe_kva) {
1424 pmap_qremove(cpipe->pipe_kva, XIO_INTERNAL_PAGES);
1425 kmem_free(&kernel_map, cpipe->pipe_kva, XIO_INTERNAL_SIZE);
1426 cpipe->pipe_kva = 0;
1427 }
1428
1429 /*
1430 * free or cache resources
1431 */
1432 gd = mycpu;
1433 if (gd->gd_pipeqcount >= pipe_maxcache ||
1434 cpipe->pipe_buffer.size != PIPE_SIZE
1435 ) {
1436 pipe_free_kmem(cpipe);
1437 kfree(cpipe, M_PIPE);
1438 } else {
1439 KKASSERT(cpipe->pipe_map.xio_npages == 0 &&
1440 cpipe->pipe_map.xio_bytes == 0 &&
1441 cpipe->pipe_map.xio_offset == 0);
1442 cpipe->pipe_state = 0;
1443 cpipe->pipe_busy = 0;
1444 cpipe->pipe_peer = gd->gd_pipeq;
1445 gd->gd_pipeq = cpipe;
1446 ++gd->gd_pipeqcount;
1447 }
1448 }
1449
1450 /*
1451 * MPALMOSTSAFE - acquires mplock
1452 */
1453 static int
1454 pipe_kqfilter(struct file *fp, struct knote *kn)
1455 {
1456 struct pipe *cpipe;
1457
1458 get_mplock();
1459 cpipe = (struct pipe *)kn->kn_fp->f_data;
1460
1461 switch (kn->kn_filter) {
1462 case EVFILT_READ:
1463 kn->kn_fop = &pipe_rfiltops;
1464 break;
1465 case EVFILT_WRITE:
1466 kn->kn_fop = &pipe_wfiltops;
1467 cpipe = cpipe->pipe_peer;
1468 if (cpipe == NULL) {
1469 /* other end of pipe has been closed */
1470 rel_mplock();
1471 return (EPIPE);
1472 }
1473 break;
1474 default:
1475 return (1);
1476 }
1477 kn->kn_hook = (caddr_t)cpipe;
1478
1479 SLIST_INSERT_HEAD(&cpipe->pipe_sel.si_note, kn, kn_selnext);
1480 rel_mplock();
1481 return (0);
1482 }
1483
1484 static void
1485 filt_pipedetach(struct knote *kn)
1486 {
1487 struct pipe *cpipe = (struct pipe *)kn->kn_hook;
1488
1489 SLIST_REMOVE(&cpipe->pipe_sel.si_note, kn, knote, kn_selnext);
1490 }
1491
1492 /*ARGSUSED*/
1493 static int
1494 filt_piperead(struct knote *kn, long hint)
1495 {
1496 struct pipe *rpipe = (struct pipe *)kn->kn_fp->f_data;
1497 struct pipe *wpipe = rpipe->pipe_peer;
1498
1499 kn->kn_data = rpipe->pipe_buffer.cnt;
1500 if ((kn->kn_data == 0) && (rpipe->pipe_state & PIPE_DIRECTW)) {
1501 kn->kn_data = rpipe->pipe_map.xio_bytes -
1502 rpipe->pipe_buffer.out;
1503 }
1504
1505 if ((rpipe->pipe_state & PIPE_EOF) ||
1506 (wpipe == NULL) || (wpipe->pipe_state & PIPE_EOF)) {
1507 kn->kn_flags |= EV_EOF;
1508 return (1);
1509 }
1510 return (kn->kn_data > 0);
1511 }
1512
1513 /*ARGSUSED*/
1514 static int
1515 filt_pipewrite(struct knote *kn, long hint)
1516 {
1517 struct pipe *rpipe = (struct pipe *)kn->kn_fp->f_data;
1518 struct pipe *wpipe = rpipe->pipe_peer;
1519
1520 if ((wpipe == NULL) || (wpipe->pipe_state & PIPE_EOF)) {
1521 kn->kn_data = 0;
1522 kn->kn_flags |= EV_EOF;
1523 return (1);
1524 }
1525 kn->kn_data = wpipe->pipe_buffer.size - wpipe->pipe_buffer.cnt;
1526 if (wpipe->pipe_state & PIPE_DIRECTW)
1527 kn->kn_data = 0;
1528
1529 return (kn->kn_data >= PIPE_BUF);
1530 }
DragonFly BSD