1 | /* $NetBSD: sys_pipe.c,v 1.140 2014/09/05 09:20:59 matt Exp $ */ |
2 | |
3 | /*- |
4 | * Copyright (c) 2003, 2007, 2008, 2009 The NetBSD Foundation, Inc. |
5 | * All rights reserved. |
6 | * |
7 | * This code is derived from software contributed to The NetBSD Foundation |
8 | * by Paul Kranenburg, and by Andrew Doran. |
9 | * |
10 | * Redistribution and use in source and binary forms, with or without |
11 | * modification, are permitted provided that the following conditions |
12 | * are met: |
13 | * 1. Redistributions of source code must retain the above copyright |
14 | * notice, this list of conditions and the following disclaimer. |
15 | * 2. Redistributions in binary form must reproduce the above copyright |
16 | * notice, this list of conditions and the following disclaimer in the |
17 | * documentation and/or other materials provided with the distribution. |
18 | * |
19 | * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS |
20 | * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED |
21 | * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR |
22 | * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS |
23 | * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
24 | * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
25 | * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
26 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
27 | * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
28 | * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
29 | * POSSIBILITY OF SUCH DAMAGE. |
30 | */ |
31 | |
32 | /* |
33 | * Copyright (c) 1996 John S. Dyson |
34 | * All rights reserved. |
35 | * |
36 | * Redistribution and use in source and binary forms, with or without |
37 | * modification, are permitted provided that the following conditions |
38 | * are met: |
39 | * 1. Redistributions of source code must retain the above copyright |
40 | * notice immediately at the beginning of the file, without modification, |
41 | * this list of conditions, and the following disclaimer. |
42 | * 2. Redistributions in binary form must reproduce the above copyright |
43 | * notice, this list of conditions and the following disclaimer in the |
44 | * documentation and/or other materials provided with the distribution. |
45 | * 3. Absolutely no warranty of function or purpose is made by the author |
46 | * John S. Dyson. |
47 | * 4. Modifications may be freely made to this file if the above conditions |
48 | * are met. |
49 | */ |
50 | |
51 | /* |
52 | * This file contains a high-performance replacement for the socket-based |
53 | * pipes scheme originally used. It does not support all features of |
54 | * sockets, but does do everything that pipes normally do. |
55 | * |
56 | * This code has two modes of operation, a small write mode and a large |
57 | * write mode. The small write mode acts like conventional pipes with |
58 | * a kernel buffer. If the buffer is less than PIPE_MINDIRECT, then the |
59 | * "normal" pipe buffering is done. If the buffer is between PIPE_MINDIRECT |
60 | * and PIPE_SIZE in size it is mapped read-only into the kernel address space |
61 | * using the UVM page loan facility from where the receiving process can copy |
62 | * the data directly from the pages in the sending process. |
63 | * |
64 | * The constant PIPE_MINDIRECT is chosen to make sure that buffering will |
65 | * happen for small transfers so that the system will not spend all of |
66 | * its time context switching. PIPE_SIZE is constrained by the |
67 | * amount of kernel virtual memory. |
68 | */ |
69 | |
70 | #include <sys/cdefs.h> |
71 | __KERNEL_RCSID(0, "$NetBSD: sys_pipe.c,v 1.140 2014/09/05 09:20:59 matt Exp $" ); |
72 | |
73 | #include <sys/param.h> |
74 | #include <sys/systm.h> |
75 | #include <sys/proc.h> |
76 | #include <sys/fcntl.h> |
77 | #include <sys/file.h> |
78 | #include <sys/filedesc.h> |
79 | #include <sys/filio.h> |
80 | #include <sys/kernel.h> |
81 | #include <sys/ttycom.h> |
82 | #include <sys/stat.h> |
83 | #include <sys/poll.h> |
84 | #include <sys/signalvar.h> |
85 | #include <sys/vnode.h> |
86 | #include <sys/uio.h> |
87 | #include <sys/select.h> |
88 | #include <sys/mount.h> |
89 | #include <sys/syscallargs.h> |
90 | #include <sys/sysctl.h> |
91 | #include <sys/kauth.h> |
92 | #include <sys/atomic.h> |
93 | #include <sys/pipe.h> |
94 | |
95 | #include <uvm/uvm_extern.h> |
96 | |
97 | /* |
98 | * Use this to disable direct I/O and decrease the code size: |
99 | * #define PIPE_NODIRECT |
100 | */ |
101 | |
102 | /* XXX Disabled for now; rare hangs switching between direct/buffered */ |
103 | #define PIPE_NODIRECT |
104 | |
105 | static int pipe_read(file_t *, off_t *, struct uio *, kauth_cred_t, int); |
106 | static int pipe_write(file_t *, off_t *, struct uio *, kauth_cred_t, int); |
107 | static int pipe_close(file_t *); |
108 | static int pipe_poll(file_t *, int); |
109 | static int pipe_kqfilter(file_t *, struct knote *); |
110 | static int pipe_stat(file_t *, struct stat *); |
111 | static int pipe_ioctl(file_t *, u_long, void *); |
112 | static void pipe_restart(file_t *); |
113 | |
114 | static const struct fileops pipeops = { |
115 | .fo_read = pipe_read, |
116 | .fo_write = pipe_write, |
117 | .fo_ioctl = pipe_ioctl, |
118 | .fo_fcntl = fnullop_fcntl, |
119 | .fo_poll = pipe_poll, |
120 | .fo_stat = pipe_stat, |
121 | .fo_close = pipe_close, |
122 | .fo_kqfilter = pipe_kqfilter, |
123 | .fo_restart = pipe_restart, |
124 | }; |
125 | |
126 | /* |
127 | * Default pipe buffer size(s), this can be kind-of large now because pipe |
128 | * space is pageable. The pipe code will try to maintain locality of |
129 | * reference for performance reasons, so small amounts of outstanding I/O |
130 | * will not wipe the cache. |
131 | */ |
132 | #define MINPIPESIZE (PIPE_SIZE / 3) |
133 | #define MAXPIPESIZE (2 * PIPE_SIZE / 3) |
134 | |
135 | /* |
136 | * Maximum amount of kva for pipes -- this is kind-of a soft limit, but |
137 | * is there so that on large systems, we don't exhaust it. |
138 | */ |
139 | #define MAXPIPEKVA (8 * 1024 * 1024) |
140 | static u_int maxpipekva = MAXPIPEKVA; |
141 | |
142 | /* |
143 | * Limit for direct transfers, we cannot, of course limit |
144 | * the amount of kva for pipes in general though. |
145 | */ |
146 | #define LIMITPIPEKVA (16 * 1024 * 1024) |
147 | static u_int limitpipekva = LIMITPIPEKVA; |
148 | |
149 | /* |
150 | * Limit the number of "big" pipes |
151 | */ |
152 | #define LIMITBIGPIPES 32 |
153 | static u_int maxbigpipes = LIMITBIGPIPES; |
154 | static u_int nbigpipe = 0; |
155 | |
156 | /* |
157 | * Amount of KVA consumed by pipe buffers. |
158 | */ |
159 | static u_int amountpipekva = 0; |
160 | |
161 | static void pipeclose(struct pipe *); |
162 | static void pipe_free_kmem(struct pipe *); |
163 | static int pipe_create(struct pipe **, pool_cache_t); |
164 | static int pipelock(struct pipe *, bool); |
165 | static inline void pipeunlock(struct pipe *); |
166 | static void pipeselwakeup(struct pipe *, struct pipe *, int); |
167 | #ifndef PIPE_NODIRECT |
168 | static int pipe_direct_write(file_t *, struct pipe *, struct uio *); |
169 | #endif |
170 | static int pipespace(struct pipe *, int); |
171 | static int pipe_ctor(void *, void *, int); |
172 | static void pipe_dtor(void *, void *); |
173 | |
174 | #ifndef PIPE_NODIRECT |
175 | static int pipe_loan_alloc(struct pipe *, int); |
176 | static void pipe_loan_free(struct pipe *); |
177 | #endif /* PIPE_NODIRECT */ |
178 | |
179 | static pool_cache_t pipe_wr_cache; |
180 | static pool_cache_t pipe_rd_cache; |
181 | |
182 | void |
183 | pipe_init(void) |
184 | { |
185 | |
186 | /* Writer side is not automatically allocated KVA. */ |
187 | pipe_wr_cache = pool_cache_init(sizeof(struct pipe), 0, 0, 0, "pipewr" , |
188 | NULL, IPL_NONE, pipe_ctor, pipe_dtor, NULL); |
189 | KASSERT(pipe_wr_cache != NULL); |
190 | |
191 | /* Reader side gets preallocated KVA. */ |
192 | pipe_rd_cache = pool_cache_init(sizeof(struct pipe), 0, 0, 0, "piperd" , |
193 | NULL, IPL_NONE, pipe_ctor, pipe_dtor, (void *)1); |
194 | KASSERT(pipe_rd_cache != NULL); |
195 | } |
196 | |
197 | static int |
198 | pipe_ctor(void *arg, void *obj, int flags) |
199 | { |
200 | struct pipe *pipe; |
201 | vaddr_t va; |
202 | |
203 | pipe = obj; |
204 | |
205 | memset(pipe, 0, sizeof(struct pipe)); |
206 | if (arg != NULL) { |
207 | /* Preallocate space. */ |
208 | va = uvm_km_alloc(kernel_map, PIPE_SIZE, 0, |
209 | UVM_KMF_PAGEABLE | UVM_KMF_WAITVA); |
210 | KASSERT(va != 0); |
211 | pipe->pipe_kmem = va; |
212 | atomic_add_int(&amountpipekva, PIPE_SIZE); |
213 | } |
214 | cv_init(&pipe->pipe_rcv, "pipe_rd" ); |
215 | cv_init(&pipe->pipe_wcv, "pipe_wr" ); |
216 | cv_init(&pipe->pipe_draincv, "pipe_drn" ); |
217 | cv_init(&pipe->pipe_lkcv, "pipe_lk" ); |
218 | selinit(&pipe->pipe_sel); |
219 | pipe->pipe_state = PIPE_SIGNALR; |
220 | |
221 | return 0; |
222 | } |
223 | |
224 | static void |
225 | pipe_dtor(void *arg, void *obj) |
226 | { |
227 | struct pipe *pipe; |
228 | |
229 | pipe = obj; |
230 | |
231 | cv_destroy(&pipe->pipe_rcv); |
232 | cv_destroy(&pipe->pipe_wcv); |
233 | cv_destroy(&pipe->pipe_draincv); |
234 | cv_destroy(&pipe->pipe_lkcv); |
235 | seldestroy(&pipe->pipe_sel); |
236 | if (pipe->pipe_kmem != 0) { |
237 | uvm_km_free(kernel_map, pipe->pipe_kmem, PIPE_SIZE, |
238 | UVM_KMF_PAGEABLE); |
239 | atomic_add_int(&amountpipekva, -PIPE_SIZE); |
240 | } |
241 | } |
242 | |
243 | /* |
244 | * The pipe system call for the DTYPE_PIPE type of pipes |
245 | */ |
246 | int |
247 | pipe1(struct lwp *l, register_t *retval, int flags) |
248 | { |
249 | struct pipe *rpipe, *wpipe; |
250 | file_t *rf, *wf; |
251 | int fd, error; |
252 | proc_t *p; |
253 | |
254 | if (flags & ~(O_CLOEXEC|O_NONBLOCK|O_NOSIGPIPE)) |
255 | return EINVAL; |
256 | p = curproc; |
257 | rpipe = wpipe = NULL; |
258 | if ((error = pipe_create(&rpipe, pipe_rd_cache)) || |
259 | (error = pipe_create(&wpipe, pipe_wr_cache))) { |
260 | goto free2; |
261 | } |
262 | rpipe->pipe_lock = mutex_obj_alloc(MUTEX_DEFAULT, IPL_NONE); |
263 | wpipe->pipe_lock = rpipe->pipe_lock; |
264 | mutex_obj_hold(wpipe->pipe_lock); |
265 | |
266 | error = fd_allocfile(&rf, &fd); |
267 | if (error) |
268 | goto free2; |
269 | retval[0] = fd; |
270 | |
271 | error = fd_allocfile(&wf, &fd); |
272 | if (error) |
273 | goto free3; |
274 | retval[1] = fd; |
275 | |
276 | rf->f_flag = FREAD | flags; |
277 | rf->f_type = DTYPE_PIPE; |
278 | rf->f_pipe = rpipe; |
279 | rf->f_ops = &pipeops; |
280 | fd_set_exclose(l, (int)retval[0], (flags & O_CLOEXEC) != 0); |
281 | |
282 | wf->f_flag = FWRITE | flags; |
283 | wf->f_type = DTYPE_PIPE; |
284 | wf->f_pipe = wpipe; |
285 | wf->f_ops = &pipeops; |
286 | fd_set_exclose(l, (int)retval[1], (flags & O_CLOEXEC) != 0); |
287 | |
288 | rpipe->pipe_peer = wpipe; |
289 | wpipe->pipe_peer = rpipe; |
290 | |
291 | fd_affix(p, rf, (int)retval[0]); |
292 | fd_affix(p, wf, (int)retval[1]); |
293 | return (0); |
294 | free3: |
295 | fd_abort(p, rf, (int)retval[0]); |
296 | free2: |
297 | pipeclose(wpipe); |
298 | pipeclose(rpipe); |
299 | |
300 | return (error); |
301 | } |
302 | |
303 | /* |
304 | * Allocate kva for pipe circular buffer, the space is pageable |
305 | * This routine will 'realloc' the size of a pipe safely, if it fails |
306 | * it will retain the old buffer. |
307 | * If it fails it will return ENOMEM. |
308 | */ |
309 | static int |
310 | pipespace(struct pipe *pipe, int size) |
311 | { |
312 | void *buffer; |
313 | |
314 | /* |
315 | * Allocate pageable virtual address space. Physical memory is |
316 | * allocated on demand. |
317 | */ |
318 | if (size == PIPE_SIZE && pipe->pipe_kmem != 0) { |
319 | buffer = (void *)pipe->pipe_kmem; |
320 | } else { |
321 | buffer = (void *)uvm_km_alloc(kernel_map, round_page(size), |
322 | 0, UVM_KMF_PAGEABLE); |
323 | if (buffer == NULL) |
324 | return (ENOMEM); |
325 | atomic_add_int(&amountpipekva, size); |
326 | } |
327 | |
328 | /* free old resources if we're resizing */ |
329 | pipe_free_kmem(pipe); |
330 | pipe->pipe_buffer.buffer = buffer; |
331 | pipe->pipe_buffer.size = size; |
332 | pipe->pipe_buffer.in = 0; |
333 | pipe->pipe_buffer.out = 0; |
334 | pipe->pipe_buffer.cnt = 0; |
335 | return (0); |
336 | } |
337 | |
338 | /* |
339 | * Initialize and allocate VM and memory for pipe. |
340 | */ |
341 | static int |
342 | pipe_create(struct pipe **pipep, pool_cache_t cache) |
343 | { |
344 | struct pipe *pipe; |
345 | int error; |
346 | |
347 | pipe = pool_cache_get(cache, PR_WAITOK); |
348 | KASSERT(pipe != NULL); |
349 | *pipep = pipe; |
350 | error = 0; |
351 | getnanotime(&pipe->pipe_btime); |
352 | pipe->pipe_atime = pipe->pipe_mtime = pipe->pipe_btime; |
353 | pipe->pipe_lock = NULL; |
354 | if (cache == pipe_rd_cache) { |
355 | error = pipespace(pipe, PIPE_SIZE); |
356 | } else { |
357 | pipe->pipe_buffer.buffer = NULL; |
358 | pipe->pipe_buffer.size = 0; |
359 | pipe->pipe_buffer.in = 0; |
360 | pipe->pipe_buffer.out = 0; |
361 | pipe->pipe_buffer.cnt = 0; |
362 | } |
363 | return error; |
364 | } |
365 | |
366 | /* |
367 | * Lock a pipe for I/O, blocking other access |
368 | * Called with pipe spin lock held. |
369 | */ |
370 | static int |
371 | pipelock(struct pipe *pipe, bool catch_p) |
372 | { |
373 | int error; |
374 | |
375 | KASSERT(mutex_owned(pipe->pipe_lock)); |
376 | |
377 | while (pipe->pipe_state & PIPE_LOCKFL) { |
378 | pipe->pipe_state |= PIPE_LWANT; |
379 | if (catch_p) { |
380 | error = cv_wait_sig(&pipe->pipe_lkcv, pipe->pipe_lock); |
381 | if (error != 0) |
382 | return error; |
383 | } else |
384 | cv_wait(&pipe->pipe_lkcv, pipe->pipe_lock); |
385 | } |
386 | |
387 | pipe->pipe_state |= PIPE_LOCKFL; |
388 | |
389 | return 0; |
390 | } |
391 | |
392 | /* |
393 | * unlock a pipe I/O lock |
394 | */ |
395 | static inline void |
396 | pipeunlock(struct pipe *pipe) |
397 | { |
398 | |
399 | KASSERT(pipe->pipe_state & PIPE_LOCKFL); |
400 | |
401 | pipe->pipe_state &= ~PIPE_LOCKFL; |
402 | if (pipe->pipe_state & PIPE_LWANT) { |
403 | pipe->pipe_state &= ~PIPE_LWANT; |
404 | cv_broadcast(&pipe->pipe_lkcv); |
405 | } |
406 | } |
407 | |
408 | /* |
409 | * Select/poll wakup. This also sends SIGIO to peer connected to |
410 | * 'sigpipe' side of pipe. |
411 | */ |
412 | static void |
413 | pipeselwakeup(struct pipe *selp, struct pipe *sigp, int code) |
414 | { |
415 | int band; |
416 | |
417 | switch (code) { |
418 | case POLL_IN: |
419 | band = POLLIN|POLLRDNORM; |
420 | break; |
421 | case POLL_OUT: |
422 | band = POLLOUT|POLLWRNORM; |
423 | break; |
424 | case POLL_HUP: |
425 | band = POLLHUP; |
426 | break; |
427 | case POLL_ERR: |
428 | band = POLLERR; |
429 | break; |
430 | default: |
431 | band = 0; |
432 | #ifdef DIAGNOSTIC |
433 | printf("bad siginfo code %d in pipe notification.\n" , code); |
434 | #endif |
435 | break; |
436 | } |
437 | |
438 | selnotify(&selp->pipe_sel, band, NOTE_SUBMIT); |
439 | |
440 | if (sigp == NULL || (sigp->pipe_state & PIPE_ASYNC) == 0) |
441 | return; |
442 | |
443 | fownsignal(sigp->pipe_pgid, SIGIO, code, band, selp); |
444 | } |
445 | |
446 | static int |
447 | pipe_read(file_t *fp, off_t *offset, struct uio *uio, kauth_cred_t cred, |
448 | int flags) |
449 | { |
450 | struct pipe *rpipe = fp->f_pipe; |
451 | struct pipebuf *bp = &rpipe->pipe_buffer; |
452 | kmutex_t *lock = rpipe->pipe_lock; |
453 | int error; |
454 | size_t nread = 0; |
455 | size_t size; |
456 | size_t ocnt; |
457 | unsigned int wakeup_state = 0; |
458 | |
459 | mutex_enter(lock); |
460 | ++rpipe->pipe_busy; |
461 | ocnt = bp->cnt; |
462 | |
463 | again: |
464 | error = pipelock(rpipe, true); |
465 | if (error) |
466 | goto unlocked_error; |
467 | |
468 | while (uio->uio_resid) { |
469 | /* |
470 | * Normal pipe buffer receive. |
471 | */ |
472 | if (bp->cnt > 0) { |
473 | size = bp->size - bp->out; |
474 | if (size > bp->cnt) |
475 | size = bp->cnt; |
476 | if (size > uio->uio_resid) |
477 | size = uio->uio_resid; |
478 | |
479 | mutex_exit(lock); |
480 | error = uiomove((char *)bp->buffer + bp->out, size, uio); |
481 | mutex_enter(lock); |
482 | if (error) |
483 | break; |
484 | |
485 | bp->out += size; |
486 | if (bp->out >= bp->size) |
487 | bp->out = 0; |
488 | |
489 | bp->cnt -= size; |
490 | |
491 | /* |
492 | * If there is no more to read in the pipe, reset |
493 | * its pointers to the beginning. This improves |
494 | * cache hit stats. |
495 | */ |
496 | if (bp->cnt == 0) { |
497 | bp->in = 0; |
498 | bp->out = 0; |
499 | } |
500 | nread += size; |
501 | continue; |
502 | } |
503 | |
504 | #ifndef PIPE_NODIRECT |
505 | if ((rpipe->pipe_state & PIPE_DIRECTR) != 0) { |
506 | struct pipemapping * const rmap = &rpipe->pipe_map; |
507 | /* |
508 | * Direct copy, bypassing a kernel buffer. |
509 | */ |
510 | void *va; |
511 | u_int gen; |
512 | |
513 | KASSERT(rpipe->pipe_state & PIPE_DIRECTW); |
514 | |
515 | size = rmap->cnt; |
516 | if (size > uio->uio_resid) |
517 | size = uio->uio_resid; |
518 | |
519 | va = (char *)rmap->kva + rmap->pos; |
520 | gen = rmap->egen; |
521 | mutex_exit(lock); |
522 | |
523 | /* |
524 | * Consume emap and read the data from loaned pages. |
525 | */ |
526 | uvm_emap_consume(gen); |
527 | error = uiomove(va, size, uio); |
528 | |
529 | mutex_enter(lock); |
530 | if (error) |
531 | break; |
532 | nread += size; |
533 | rmap->pos += size; |
534 | rmap->cnt -= size; |
535 | if (rmap->cnt == 0) { |
536 | rpipe->pipe_state &= ~PIPE_DIRECTR; |
537 | cv_broadcast(&rpipe->pipe_wcv); |
538 | } |
539 | continue; |
540 | } |
541 | #endif |
542 | /* |
543 | * Break if some data was read. |
544 | */ |
545 | if (nread > 0) |
546 | break; |
547 | |
548 | /* |
549 | * Detect EOF condition. |
550 | * Read returns 0 on EOF, no need to set error. |
551 | */ |
552 | if (rpipe->pipe_state & PIPE_EOF) |
553 | break; |
554 | |
555 | /* |
556 | * Don't block on non-blocking I/O. |
557 | */ |
558 | if (fp->f_flag & FNONBLOCK) { |
559 | error = EAGAIN; |
560 | break; |
561 | } |
562 | |
563 | /* |
564 | * Unlock the pipe buffer for our remaining processing. |
565 | * We will either break out with an error or we will |
566 | * sleep and relock to loop. |
567 | */ |
568 | pipeunlock(rpipe); |
569 | |
570 | /* |
571 | * Re-check to see if more direct writes are pending. |
572 | */ |
573 | if ((rpipe->pipe_state & PIPE_DIRECTR) != 0) |
574 | goto again; |
575 | |
576 | #if 1 /* XXX (dsl) I'm sure these aren't needed here ... */ |
577 | /* |
578 | * We want to read more, wake up select/poll. |
579 | */ |
580 | pipeselwakeup(rpipe, rpipe->pipe_peer, POLL_OUT); |
581 | |
582 | /* |
583 | * If the "write-side" is blocked, wake it up now. |
584 | */ |
585 | cv_broadcast(&rpipe->pipe_wcv); |
586 | #endif |
587 | |
588 | if (wakeup_state & PIPE_RESTART) { |
589 | error = ERESTART; |
590 | goto unlocked_error; |
591 | } |
592 | |
593 | /* Now wait until the pipe is filled */ |
594 | error = cv_wait_sig(&rpipe->pipe_rcv, lock); |
595 | if (error != 0) |
596 | goto unlocked_error; |
597 | wakeup_state = rpipe->pipe_state; |
598 | goto again; |
599 | } |
600 | |
601 | if (error == 0) |
602 | getnanotime(&rpipe->pipe_atime); |
603 | pipeunlock(rpipe); |
604 | |
605 | unlocked_error: |
606 | --rpipe->pipe_busy; |
607 | if (rpipe->pipe_busy == 0) { |
608 | rpipe->pipe_state &= ~PIPE_RESTART; |
609 | cv_broadcast(&rpipe->pipe_draincv); |
610 | } |
611 | if (bp->cnt < MINPIPESIZE) { |
612 | cv_broadcast(&rpipe->pipe_wcv); |
613 | } |
614 | |
615 | /* |
616 | * If anything was read off the buffer, signal to the writer it's |
617 | * possible to write more data. Also send signal if we are here for the |
618 | * first time after last write. |
619 | */ |
620 | if ((bp->size - bp->cnt) >= PIPE_BUF |
621 | && (ocnt != bp->cnt || (rpipe->pipe_state & PIPE_SIGNALR))) { |
622 | pipeselwakeup(rpipe, rpipe->pipe_peer, POLL_OUT); |
623 | rpipe->pipe_state &= ~PIPE_SIGNALR; |
624 | } |
625 | |
626 | mutex_exit(lock); |
627 | return (error); |
628 | } |
629 | |
630 | #ifndef PIPE_NODIRECT |
631 | /* |
632 | * Allocate structure for loan transfer. |
633 | */ |
634 | static int |
635 | pipe_loan_alloc(struct pipe *wpipe, int npages) |
636 | { |
637 | struct pipemapping * const wmap = &wpipe->pipe_map; |
638 | const vsize_t len = ptoa(npages); |
639 | |
640 | atomic_add_int(&amountpipekva, len); |
641 | wmap->kva = uvm_km_alloc(kernel_map, len, 0, |
642 | UVM_KMF_COLORMATCH | UVM_KMF_VAONLY | UVM_KMF_WAITVA); |
643 | if (wmap->kva == 0) { |
644 | atomic_add_int(&amountpipekva, -len); |
645 | return (ENOMEM); |
646 | } |
647 | |
648 | wmap->npages = npages; |
649 | wmap->pgs = kmem_alloc(npages * sizeof(struct vm_page *), KM_SLEEP); |
650 | return (0); |
651 | } |
652 | |
653 | /* |
654 | * Free resources allocated for loan transfer. |
655 | */ |
656 | static void |
657 | pipe_loan_free(struct pipe *wpipe) |
658 | { |
659 | struct pipemapping * const wmap = &wpipe->pipe_map; |
660 | const vsize_t len = ptoa(wmap->npages); |
661 | |
662 | uvm_emap_remove(wmap->kva, len); /* XXX */ |
663 | uvm_km_free(kernel_map, wmap->kva, len, UVM_KMF_VAONLY); |
664 | wmap->kva = 0; |
665 | atomic_add_int(&amountpipekva, -len); |
666 | kmem_free(wmap->pgs, wmap->npages * sizeof(struct vm_page *)); |
667 | wmap->pgs = NULL; |
668 | #if 0 |
669 | wmap->npages = 0; |
670 | wmap->pos = 0; |
671 | wmap->cnt = 0; |
672 | #endif |
673 | } |
674 | |
675 | /* |
676 | * NetBSD direct write, using uvm_loan() mechanism. |
677 | * This implements the pipe buffer write mechanism. Note that only |
678 | * a direct write OR a normal pipe write can be pending at any given time. |
679 | * If there are any characters in the pipe buffer, the direct write will |
680 | * be deferred until the receiving process grabs all of the bytes from |
681 | * the pipe buffer. Then the direct mapping write is set-up. |
682 | * |
683 | * Called with the long-term pipe lock held. |
684 | */ |
685 | static int |
686 | pipe_direct_write(file_t *fp, struct pipe *wpipe, struct uio *uio) |
687 | { |
688 | struct pipemapping * const wmap = &wpipe->pipe_map; |
689 | kmutex_t * const lock = wpipe->pipe_lock; |
690 | struct vm_page **pgs; |
691 | vaddr_t bbase, base, bend; |
692 | vsize_t blen, bcnt; |
693 | int error, npages; |
694 | voff_t bpos; |
695 | u_int starting_color; |
696 | |
697 | KASSERT(mutex_owned(wpipe->pipe_lock)); |
698 | KASSERT(wmap->cnt == 0); |
699 | |
700 | mutex_exit(lock); |
701 | |
702 | /* |
703 | * Handle first PIPE_CHUNK_SIZE bytes of buffer. Deal with buffers |
704 | * not aligned to PAGE_SIZE. |
705 | */ |
706 | bbase = (vaddr_t)uio->uio_iov->iov_base; |
707 | base = trunc_page(bbase); |
708 | bend = round_page(bbase + uio->uio_iov->iov_len); |
709 | blen = bend - base; |
710 | bpos = bbase - base; |
711 | |
712 | if (blen > PIPE_DIRECT_CHUNK) { |
713 | blen = PIPE_DIRECT_CHUNK; |
714 | bend = base + blen; |
715 | bcnt = PIPE_DIRECT_CHUNK - bpos; |
716 | } else { |
717 | bcnt = uio->uio_iov->iov_len; |
718 | } |
719 | npages = atop(blen); |
720 | starting_color = atop(base) & uvmexp.colormask; |
721 | |
722 | /* |
723 | * Free the old kva if we need more pages than we have |
724 | * allocated. |
725 | */ |
726 | if (wmap->kva != 0 && starting_color + npages > wmap->npages) |
727 | pipe_loan_free(wpipe); |
728 | |
729 | /* Allocate new kva. */ |
730 | if (wmap->kva == 0) { |
731 | error = pipe_loan_alloc(wpipe, starting_color + npages); |
732 | if (error) { |
733 | mutex_enter(lock); |
734 | return (error); |
735 | } |
736 | } |
737 | |
738 | /* Loan the write buffer memory from writer process */ |
739 | pgs = wmap->pgs + starting_color; |
740 | error = uvm_loan(&uio->uio_vmspace->vm_map, base, blen, |
741 | pgs, UVM_LOAN_TOPAGE); |
742 | if (error) { |
743 | pipe_loan_free(wpipe); |
744 | mutex_enter(lock); |
745 | return (ENOMEM); /* so that caller fallback to ordinary write */ |
746 | } |
747 | |
748 | /* Enter the loaned pages to KVA, produce new emap generation number. */ |
749 | uvm_emap_enter(wmap->kva + ptoa(starting_color), pgs, npages); |
750 | wmap->egen = uvm_emap_produce(); |
751 | |
752 | /* Now we can put the pipe in direct write mode */ |
753 | wmap->pos = bpos + ptoa(starting_color); |
754 | wmap->cnt = bcnt; |
755 | |
756 | /* |
757 | * But before we can let someone do a direct read, we |
758 | * have to wait until the pipe is drained. Release the |
759 | * pipe lock while we wait. |
760 | */ |
761 | mutex_enter(lock); |
762 | wpipe->pipe_state |= PIPE_DIRECTW; |
763 | pipeunlock(wpipe); |
764 | |
765 | while (error == 0 && wpipe->pipe_buffer.cnt > 0) { |
766 | cv_broadcast(&wpipe->pipe_rcv); |
767 | error = cv_wait_sig(&wpipe->pipe_wcv, lock); |
768 | if (error == 0 && wpipe->pipe_state & PIPE_EOF) |
769 | error = EPIPE; |
770 | } |
771 | |
772 | /* Pipe is drained; next read will off the direct buffer */ |
773 | wpipe->pipe_state |= PIPE_DIRECTR; |
774 | |
775 | /* Wait until the reader is done */ |
776 | while (error == 0 && (wpipe->pipe_state & PIPE_DIRECTR)) { |
777 | cv_broadcast(&wpipe->pipe_rcv); |
778 | pipeselwakeup(wpipe, wpipe, POLL_IN); |
779 | error = cv_wait_sig(&wpipe->pipe_wcv, lock); |
780 | if (error == 0 && wpipe->pipe_state & PIPE_EOF) |
781 | error = EPIPE; |
782 | } |
783 | |
784 | /* Take pipe out of direct write mode */ |
785 | wpipe->pipe_state &= ~(PIPE_DIRECTW | PIPE_DIRECTR); |
786 | |
787 | /* Acquire the pipe lock and cleanup */ |
788 | (void)pipelock(wpipe, false); |
789 | mutex_exit(lock); |
790 | |
791 | if (pgs != NULL) { |
792 | /* XXX: uvm_emap_remove */ |
793 | uvm_unloan(pgs, npages, UVM_LOAN_TOPAGE); |
794 | } |
795 | if (error || amountpipekva > maxpipekva) |
796 | pipe_loan_free(wpipe); |
797 | |
798 | mutex_enter(lock); |
799 | if (error) { |
800 | pipeselwakeup(wpipe, wpipe, POLL_ERR); |
801 | |
802 | /* |
803 | * If nothing was read from what we offered, return error |
804 | * straight on. Otherwise update uio resid first. Caller |
805 | * will deal with the error condition, returning short |
806 | * write, error, or restarting the write(2) as appropriate. |
807 | */ |
808 | if (wmap->cnt == bcnt) { |
809 | wmap->cnt = 0; |
810 | cv_broadcast(&wpipe->pipe_wcv); |
811 | return (error); |
812 | } |
813 | |
814 | bcnt -= wpipe->cnt; |
815 | } |
816 | |
817 | uio->uio_resid -= bcnt; |
818 | /* uio_offset not updated, not set/used for write(2) */ |
819 | uio->uio_iov->iov_base = (char *)uio->uio_iov->iov_base + bcnt; |
820 | uio->uio_iov->iov_len -= bcnt; |
821 | if (uio->uio_iov->iov_len == 0) { |
822 | uio->uio_iov++; |
823 | uio->uio_iovcnt--; |
824 | } |
825 | |
826 | wmap->cnt = 0; |
827 | return (error); |
828 | } |
829 | #endif /* !PIPE_NODIRECT */ |
830 | |
831 | static int |
832 | pipe_write(file_t *fp, off_t *offset, struct uio *uio, kauth_cred_t cred, |
833 | int flags) |
834 | { |
835 | struct pipe *wpipe, *rpipe; |
836 | struct pipebuf *bp; |
837 | kmutex_t *lock; |
838 | int error; |
839 | unsigned int wakeup_state = 0; |
840 | |
841 | /* We want to write to our peer */ |
842 | rpipe = fp->f_pipe; |
843 | lock = rpipe->pipe_lock; |
844 | error = 0; |
845 | |
846 | mutex_enter(lock); |
847 | wpipe = rpipe->pipe_peer; |
848 | |
849 | /* |
850 | * Detect loss of pipe read side, issue SIGPIPE if lost. |
851 | */ |
852 | if (wpipe == NULL || (wpipe->pipe_state & PIPE_EOF) != 0) { |
853 | mutex_exit(lock); |
854 | return EPIPE; |
855 | } |
856 | ++wpipe->pipe_busy; |
857 | |
858 | /* Aquire the long-term pipe lock */ |
859 | if ((error = pipelock(wpipe, true)) != 0) { |
860 | --wpipe->pipe_busy; |
861 | if (wpipe->pipe_busy == 0) { |
862 | wpipe->pipe_state &= ~PIPE_RESTART; |
863 | cv_broadcast(&wpipe->pipe_draincv); |
864 | } |
865 | mutex_exit(lock); |
866 | return (error); |
867 | } |
868 | |
869 | bp = &wpipe->pipe_buffer; |
870 | |
871 | /* |
872 | * If it is advantageous to resize the pipe buffer, do so. |
873 | */ |
874 | if ((uio->uio_resid > PIPE_SIZE) && |
875 | (nbigpipe < maxbigpipes) && |
876 | #ifndef PIPE_NODIRECT |
877 | (wpipe->pipe_state & PIPE_DIRECTW) == 0 && |
878 | #endif |
879 | (bp->size <= PIPE_SIZE) && (bp->cnt == 0)) { |
880 | |
881 | if (pipespace(wpipe, BIG_PIPE_SIZE) == 0) |
882 | atomic_inc_uint(&nbigpipe); |
883 | } |
884 | |
885 | while (uio->uio_resid) { |
886 | size_t space; |
887 | |
888 | #ifndef PIPE_NODIRECT |
889 | /* |
890 | * Pipe buffered writes cannot be coincidental with |
891 | * direct writes. Also, only one direct write can be |
892 | * in progress at any one time. We wait until the currently |
893 | * executing direct write is completed before continuing. |
894 | * |
895 | * We break out if a signal occurs or the reader goes away. |
896 | */ |
897 | while (error == 0 && wpipe->pipe_state & PIPE_DIRECTW) { |
898 | cv_broadcast(&wpipe->pipe_rcv); |
899 | pipeunlock(wpipe); |
900 | error = cv_wait_sig(&wpipe->pipe_wcv, lock); |
901 | (void)pipelock(wpipe, false); |
902 | if (wpipe->pipe_state & PIPE_EOF) |
903 | error = EPIPE; |
904 | } |
905 | if (error) |
906 | break; |
907 | |
908 | /* |
909 | * If the transfer is large, we can gain performance if |
910 | * we do process-to-process copies directly. |
911 | * If the write is non-blocking, we don't use the |
912 | * direct write mechanism. |
913 | * |
914 | * The direct write mechanism will detect the reader going |
915 | * away on us. |
916 | */ |
917 | if ((uio->uio_iov->iov_len >= PIPE_MINDIRECT) && |
918 | (fp->f_flag & FNONBLOCK) == 0 && |
919 | (wmap->kva || (amountpipekva < limitpipekva))) { |
920 | error = pipe_direct_write(fp, wpipe, uio); |
921 | |
922 | /* |
923 | * Break out if error occurred, unless it's ENOMEM. |
924 | * ENOMEM means we failed to allocate some resources |
925 | * for direct write, so we just fallback to ordinary |
926 | * write. If the direct write was successful, |
927 | * process rest of data via ordinary write. |
928 | */ |
929 | if (error == 0) |
930 | continue; |
931 | |
932 | if (error != ENOMEM) |
933 | break; |
934 | } |
935 | #endif /* PIPE_NODIRECT */ |
936 | |
937 | space = bp->size - bp->cnt; |
938 | |
939 | /* Writes of size <= PIPE_BUF must be atomic. */ |
940 | if ((space < uio->uio_resid) && (uio->uio_resid <= PIPE_BUF)) |
941 | space = 0; |
942 | |
943 | if (space > 0) { |
944 | int size; /* Transfer size */ |
945 | int segsize; /* first segment to transfer */ |
946 | |
947 | /* |
948 | * Transfer size is minimum of uio transfer |
949 | * and free space in pipe buffer. |
950 | */ |
951 | if (space > uio->uio_resid) |
952 | size = uio->uio_resid; |
953 | else |
954 | size = space; |
955 | /* |
956 | * First segment to transfer is minimum of |
957 | * transfer size and contiguous space in |
958 | * pipe buffer. If first segment to transfer |
959 | * is less than the transfer size, we've got |
960 | * a wraparound in the buffer. |
961 | */ |
962 | segsize = bp->size - bp->in; |
963 | if (segsize > size) |
964 | segsize = size; |
965 | |
966 | /* Transfer first segment */ |
967 | mutex_exit(lock); |
968 | error = uiomove((char *)bp->buffer + bp->in, segsize, |
969 | uio); |
970 | |
971 | if (error == 0 && segsize < size) { |
972 | /* |
973 | * Transfer remaining part now, to |
974 | * support atomic writes. Wraparound |
975 | * happened. |
976 | */ |
977 | KASSERT(bp->in + segsize == bp->size); |
978 | error = uiomove(bp->buffer, |
979 | size - segsize, uio); |
980 | } |
981 | mutex_enter(lock); |
982 | if (error) |
983 | break; |
984 | |
985 | bp->in += size; |
986 | if (bp->in >= bp->size) { |
987 | KASSERT(bp->in == size - segsize + bp->size); |
988 | bp->in = size - segsize; |
989 | } |
990 | |
991 | bp->cnt += size; |
992 | KASSERT(bp->cnt <= bp->size); |
993 | wakeup_state = 0; |
994 | } else { |
995 | /* |
996 | * If the "read-side" has been blocked, wake it up now. |
997 | */ |
998 | cv_broadcast(&wpipe->pipe_rcv); |
999 | |
1000 | /* |
1001 | * Don't block on non-blocking I/O. |
1002 | */ |
1003 | if (fp->f_flag & FNONBLOCK) { |
1004 | error = EAGAIN; |
1005 | break; |
1006 | } |
1007 | |
1008 | /* |
1009 | * We have no more space and have something to offer, |
1010 | * wake up select/poll. |
1011 | */ |
1012 | if (bp->cnt) |
1013 | pipeselwakeup(wpipe, wpipe, POLL_IN); |
1014 | |
1015 | if (wakeup_state & PIPE_RESTART) { |
1016 | error = ERESTART; |
1017 | break; |
1018 | } |
1019 | |
1020 | pipeunlock(wpipe); |
1021 | error = cv_wait_sig(&wpipe->pipe_wcv, lock); |
1022 | (void)pipelock(wpipe, false); |
1023 | if (error != 0) |
1024 | break; |
1025 | /* |
1026 | * If read side wants to go away, we just issue a signal |
1027 | * to ourselves. |
1028 | */ |
1029 | if (wpipe->pipe_state & PIPE_EOF) { |
1030 | error = EPIPE; |
1031 | break; |
1032 | } |
1033 | wakeup_state = wpipe->pipe_state; |
1034 | } |
1035 | } |
1036 | |
1037 | --wpipe->pipe_busy; |
1038 | if (wpipe->pipe_busy == 0) { |
1039 | wpipe->pipe_state &= ~PIPE_RESTART; |
1040 | cv_broadcast(&wpipe->pipe_draincv); |
1041 | } |
1042 | if (bp->cnt > 0) { |
1043 | cv_broadcast(&wpipe->pipe_rcv); |
1044 | } |
1045 | |
1046 | /* |
1047 | * Don't return EPIPE if I/O was successful |
1048 | */ |
1049 | if (error == EPIPE && bp->cnt == 0 && uio->uio_resid == 0) |
1050 | error = 0; |
1051 | |
1052 | if (error == 0) |
1053 | getnanotime(&wpipe->pipe_mtime); |
1054 | |
1055 | /* |
1056 | * We have something to offer, wake up select/poll. |
1057 | * wmap->cnt is always 0 in this point (direct write |
1058 | * is only done synchronously), so check only wpipe->pipe_buffer.cnt |
1059 | */ |
1060 | if (bp->cnt) |
1061 | pipeselwakeup(wpipe, wpipe, POLL_IN); |
1062 | |
1063 | /* |
1064 | * Arrange for next read(2) to do a signal. |
1065 | */ |
1066 | wpipe->pipe_state |= PIPE_SIGNALR; |
1067 | |
1068 | pipeunlock(wpipe); |
1069 | mutex_exit(lock); |
1070 | return (error); |
1071 | } |
1072 | |
1073 | /* |
1074 | * We implement a very minimal set of ioctls for compatibility with sockets. |
1075 | */ |
1076 | int |
1077 | pipe_ioctl(file_t *fp, u_long cmd, void *data) |
1078 | { |
1079 | struct pipe *pipe = fp->f_pipe; |
1080 | kmutex_t *lock = pipe->pipe_lock; |
1081 | |
1082 | switch (cmd) { |
1083 | |
1084 | case FIONBIO: |
1085 | return (0); |
1086 | |
1087 | case FIOASYNC: |
1088 | mutex_enter(lock); |
1089 | if (*(int *)data) { |
1090 | pipe->pipe_state |= PIPE_ASYNC; |
1091 | } else { |
1092 | pipe->pipe_state &= ~PIPE_ASYNC; |
1093 | } |
1094 | mutex_exit(lock); |
1095 | return (0); |
1096 | |
1097 | case FIONREAD: |
1098 | mutex_enter(lock); |
1099 | #ifndef PIPE_NODIRECT |
1100 | if (pipe->pipe_state & PIPE_DIRECTW) |
1101 | *(int *)data = pipe->pipe_map.cnt; |
1102 | else |
1103 | #endif |
1104 | *(int *)data = pipe->pipe_buffer.cnt; |
1105 | mutex_exit(lock); |
1106 | return (0); |
1107 | |
1108 | case FIONWRITE: |
1109 | /* Look at other side */ |
1110 | pipe = pipe->pipe_peer; |
1111 | mutex_enter(lock); |
1112 | #ifndef PIPE_NODIRECT |
1113 | if (pipe->pipe_state & PIPE_DIRECTW) |
1114 | *(int *)data = pipe->pipe_map.cnt; |
1115 | else |
1116 | #endif |
1117 | *(int *)data = pipe->pipe_buffer.cnt; |
1118 | mutex_exit(lock); |
1119 | return (0); |
1120 | |
1121 | case FIONSPACE: |
1122 | /* Look at other side */ |
1123 | pipe = pipe->pipe_peer; |
1124 | mutex_enter(lock); |
1125 | #ifndef PIPE_NODIRECT |
1126 | /* |
1127 | * If we're in direct-mode, we don't really have a |
1128 | * send queue, and any other write will block. Thus |
1129 | * zero seems like the best answer. |
1130 | */ |
1131 | if (pipe->pipe_state & PIPE_DIRECTW) |
1132 | *(int *)data = 0; |
1133 | else |
1134 | #endif |
1135 | *(int *)data = pipe->pipe_buffer.size - |
1136 | pipe->pipe_buffer.cnt; |
1137 | mutex_exit(lock); |
1138 | return (0); |
1139 | |
1140 | case TIOCSPGRP: |
1141 | case FIOSETOWN: |
1142 | return fsetown(&pipe->pipe_pgid, cmd, data); |
1143 | |
1144 | case TIOCGPGRP: |
1145 | case FIOGETOWN: |
1146 | return fgetown(pipe->pipe_pgid, cmd, data); |
1147 | |
1148 | } |
1149 | return (EPASSTHROUGH); |
1150 | } |
1151 | |
1152 | int |
1153 | pipe_poll(file_t *fp, int events) |
1154 | { |
1155 | struct pipe *rpipe = fp->f_pipe; |
1156 | struct pipe *wpipe; |
1157 | int eof = 0; |
1158 | int revents = 0; |
1159 | |
1160 | mutex_enter(rpipe->pipe_lock); |
1161 | wpipe = rpipe->pipe_peer; |
1162 | |
1163 | if (events & (POLLIN | POLLRDNORM)) |
1164 | if ((rpipe->pipe_buffer.cnt > 0) || |
1165 | #ifndef PIPE_NODIRECT |
1166 | (rpipe->pipe_state & PIPE_DIRECTR) || |
1167 | #endif |
1168 | (rpipe->pipe_state & PIPE_EOF)) |
1169 | revents |= events & (POLLIN | POLLRDNORM); |
1170 | |
1171 | eof |= (rpipe->pipe_state & PIPE_EOF); |
1172 | |
1173 | if (wpipe == NULL) |
1174 | revents |= events & (POLLOUT | POLLWRNORM); |
1175 | else { |
1176 | if (events & (POLLOUT | POLLWRNORM)) |
1177 | if ((wpipe->pipe_state & PIPE_EOF) || ( |
1178 | #ifndef PIPE_NODIRECT |
1179 | (wpipe->pipe_state & PIPE_DIRECTW) == 0 && |
1180 | #endif |
1181 | (wpipe->pipe_buffer.size - wpipe->pipe_buffer.cnt) >= PIPE_BUF)) |
1182 | revents |= events & (POLLOUT | POLLWRNORM); |
1183 | |
1184 | eof |= (wpipe->pipe_state & PIPE_EOF); |
1185 | } |
1186 | |
1187 | if (wpipe == NULL || eof) |
1188 | revents |= POLLHUP; |
1189 | |
1190 | if (revents == 0) { |
1191 | if (events & (POLLIN | POLLRDNORM)) |
1192 | selrecord(curlwp, &rpipe->pipe_sel); |
1193 | |
1194 | if (events & (POLLOUT | POLLWRNORM)) |
1195 | selrecord(curlwp, &wpipe->pipe_sel); |
1196 | } |
1197 | mutex_exit(rpipe->pipe_lock); |
1198 | |
1199 | return (revents); |
1200 | } |
1201 | |
1202 | static int |
1203 | pipe_stat(file_t *fp, struct stat *ub) |
1204 | { |
1205 | struct pipe *pipe = fp->f_pipe; |
1206 | |
1207 | mutex_enter(pipe->pipe_lock); |
1208 | memset(ub, 0, sizeof(*ub)); |
1209 | ub->st_mode = S_IFIFO | S_IRUSR | S_IWUSR; |
1210 | ub->st_blksize = pipe->pipe_buffer.size; |
1211 | if (ub->st_blksize == 0 && pipe->pipe_peer) |
1212 | ub->st_blksize = pipe->pipe_peer->pipe_buffer.size; |
1213 | ub->st_size = pipe->pipe_buffer.cnt; |
1214 | ub->st_blocks = (ub->st_size) ? 1 : 0; |
1215 | ub->st_atimespec = pipe->pipe_atime; |
1216 | ub->st_mtimespec = pipe->pipe_mtime; |
1217 | ub->st_ctimespec = ub->st_birthtimespec = pipe->pipe_btime; |
1218 | ub->st_uid = kauth_cred_geteuid(fp->f_cred); |
1219 | ub->st_gid = kauth_cred_getegid(fp->f_cred); |
1220 | |
1221 | /* |
1222 | * Left as 0: st_dev, st_ino, st_nlink, st_rdev, st_flags, st_gen. |
1223 | * XXX (st_dev, st_ino) should be unique. |
1224 | */ |
1225 | mutex_exit(pipe->pipe_lock); |
1226 | return 0; |
1227 | } |
1228 | |
1229 | static int |
1230 | pipe_close(file_t *fp) |
1231 | { |
1232 | struct pipe *pipe = fp->f_pipe; |
1233 | |
1234 | fp->f_pipe = NULL; |
1235 | pipeclose(pipe); |
1236 | return (0); |
1237 | } |
1238 | |
1239 | static void |
1240 | pipe_restart(file_t *fp) |
1241 | { |
1242 | struct pipe *pipe = fp->f_pipe; |
1243 | |
1244 | /* |
1245 | * Unblock blocked reads/writes in order to allow close() to complete. |
1246 | * System calls return ERESTART so that the fd is revalidated. |
1247 | * (Partial writes return the transfer length.) |
1248 | */ |
1249 | mutex_enter(pipe->pipe_lock); |
1250 | pipe->pipe_state |= PIPE_RESTART; |
1251 | /* Wakeup both cvs, maybe we only need one, but maybe there are some |
1252 | * other paths where wakeup is needed, and it saves deciding which! */ |
1253 | cv_broadcast(&pipe->pipe_rcv); |
1254 | cv_broadcast(&pipe->pipe_wcv); |
1255 | mutex_exit(pipe->pipe_lock); |
1256 | } |
1257 | |
1258 | static void |
1259 | pipe_free_kmem(struct pipe *pipe) |
1260 | { |
1261 | |
1262 | if (pipe->pipe_buffer.buffer != NULL) { |
1263 | if (pipe->pipe_buffer.size > PIPE_SIZE) { |
1264 | atomic_dec_uint(&nbigpipe); |
1265 | } |
1266 | if (pipe->pipe_buffer.buffer != (void *)pipe->pipe_kmem) { |
1267 | uvm_km_free(kernel_map, |
1268 | (vaddr_t)pipe->pipe_buffer.buffer, |
1269 | pipe->pipe_buffer.size, UVM_KMF_PAGEABLE); |
1270 | atomic_add_int(&amountpipekva, |
1271 | -pipe->pipe_buffer.size); |
1272 | } |
1273 | pipe->pipe_buffer.buffer = NULL; |
1274 | } |
1275 | #ifndef PIPE_NODIRECT |
1276 | if (pipe->pipe_map.kva != 0) { |
1277 | pipe_loan_free(pipe); |
1278 | pipe->pipe_map.cnt = 0; |
1279 | pipe->pipe_map.pos = 0; |
1280 | pipe->pipe_map.npages = 0; |
1281 | } |
1282 | #endif /* !PIPE_NODIRECT */ |
1283 | } |
1284 | |
1285 | /* |
1286 | * Shutdown the pipe. |
1287 | */ |
1288 | static void |
1289 | pipeclose(struct pipe *pipe) |
1290 | { |
1291 | kmutex_t *lock; |
1292 | struct pipe *ppipe; |
1293 | |
1294 | if (pipe == NULL) |
1295 | return; |
1296 | |
1297 | KASSERT(cv_is_valid(&pipe->pipe_rcv)); |
1298 | KASSERT(cv_is_valid(&pipe->pipe_wcv)); |
1299 | KASSERT(cv_is_valid(&pipe->pipe_draincv)); |
1300 | KASSERT(cv_is_valid(&pipe->pipe_lkcv)); |
1301 | |
1302 | lock = pipe->pipe_lock; |
1303 | if (lock == NULL) |
1304 | /* Must have failed during create */ |
1305 | goto free_resources; |
1306 | |
1307 | mutex_enter(lock); |
1308 | pipeselwakeup(pipe, pipe, POLL_HUP); |
1309 | |
1310 | /* |
1311 | * If the other side is blocked, wake it up saying that |
1312 | * we want to close it down. |
1313 | */ |
1314 | pipe->pipe_state |= PIPE_EOF; |
1315 | if (pipe->pipe_busy) { |
1316 | while (pipe->pipe_busy) { |
1317 | cv_broadcast(&pipe->pipe_wcv); |
1318 | cv_wait_sig(&pipe->pipe_draincv, lock); |
1319 | } |
1320 | } |
1321 | |
1322 | /* |
1323 | * Disconnect from peer. |
1324 | */ |
1325 | if ((ppipe = pipe->pipe_peer) != NULL) { |
1326 | pipeselwakeup(ppipe, ppipe, POLL_HUP); |
1327 | ppipe->pipe_state |= PIPE_EOF; |
1328 | cv_broadcast(&ppipe->pipe_rcv); |
1329 | ppipe->pipe_peer = NULL; |
1330 | } |
1331 | |
1332 | /* |
1333 | * Any knote objects still left in the list are |
1334 | * the one attached by peer. Since no one will |
1335 | * traverse this list, we just clear it. |
1336 | */ |
1337 | SLIST_INIT(&pipe->pipe_sel.sel_klist); |
1338 | |
1339 | KASSERT((pipe->pipe_state & PIPE_LOCKFL) == 0); |
1340 | mutex_exit(lock); |
1341 | mutex_obj_free(lock); |
1342 | |
1343 | /* |
1344 | * Free resources. |
1345 | */ |
1346 | free_resources: |
1347 | pipe->pipe_pgid = 0; |
1348 | pipe->pipe_state = PIPE_SIGNALR; |
1349 | pipe_free_kmem(pipe); |
1350 | if (pipe->pipe_kmem != 0) { |
1351 | pool_cache_put(pipe_rd_cache, pipe); |
1352 | } else { |
1353 | pool_cache_put(pipe_wr_cache, pipe); |
1354 | } |
1355 | } |
1356 | |
1357 | static void |
1358 | filt_pipedetach(struct knote *kn) |
1359 | { |
1360 | struct pipe *pipe; |
1361 | kmutex_t *lock; |
1362 | |
1363 | pipe = ((file_t *)kn->kn_obj)->f_pipe; |
1364 | lock = pipe->pipe_lock; |
1365 | |
1366 | mutex_enter(lock); |
1367 | |
1368 | switch(kn->kn_filter) { |
1369 | case EVFILT_WRITE: |
1370 | /* Need the peer structure, not our own. */ |
1371 | pipe = pipe->pipe_peer; |
1372 | |
1373 | /* If reader end already closed, just return. */ |
1374 | if (pipe == NULL) { |
1375 | mutex_exit(lock); |
1376 | return; |
1377 | } |
1378 | |
1379 | break; |
1380 | default: |
1381 | /* Nothing to do. */ |
1382 | break; |
1383 | } |
1384 | |
1385 | KASSERT(kn->kn_hook == pipe); |
1386 | SLIST_REMOVE(&pipe->pipe_sel.sel_klist, kn, knote, kn_selnext); |
1387 | mutex_exit(lock); |
1388 | } |
1389 | |
1390 | static int |
1391 | filt_piperead(struct knote *kn, long hint) |
1392 | { |
1393 | struct pipe *rpipe = ((file_t *)kn->kn_obj)->f_pipe; |
1394 | struct pipe *wpipe; |
1395 | |
1396 | if ((hint & NOTE_SUBMIT) == 0) { |
1397 | mutex_enter(rpipe->pipe_lock); |
1398 | } |
1399 | wpipe = rpipe->pipe_peer; |
1400 | kn->kn_data = rpipe->pipe_buffer.cnt; |
1401 | |
1402 | if ((kn->kn_data == 0) && (rpipe->pipe_state & PIPE_DIRECTW)) |
1403 | kn->kn_data = rpipe->pipe_map.cnt; |
1404 | |
1405 | if ((rpipe->pipe_state & PIPE_EOF) || |
1406 | (wpipe == NULL) || (wpipe->pipe_state & PIPE_EOF)) { |
1407 | kn->kn_flags |= EV_EOF; |
1408 | if ((hint & NOTE_SUBMIT) == 0) { |
1409 | mutex_exit(rpipe->pipe_lock); |
1410 | } |
1411 | return (1); |
1412 | } |
1413 | |
1414 | if ((hint & NOTE_SUBMIT) == 0) { |
1415 | mutex_exit(rpipe->pipe_lock); |
1416 | } |
1417 | return (kn->kn_data > 0); |
1418 | } |
1419 | |
1420 | static int |
1421 | filt_pipewrite(struct knote *kn, long hint) |
1422 | { |
1423 | struct pipe *rpipe = ((file_t *)kn->kn_obj)->f_pipe; |
1424 | struct pipe *wpipe; |
1425 | |
1426 | if ((hint & NOTE_SUBMIT) == 0) { |
1427 | mutex_enter(rpipe->pipe_lock); |
1428 | } |
1429 | wpipe = rpipe->pipe_peer; |
1430 | |
1431 | if ((wpipe == NULL) || (wpipe->pipe_state & PIPE_EOF)) { |
1432 | kn->kn_data = 0; |
1433 | kn->kn_flags |= EV_EOF; |
1434 | if ((hint & NOTE_SUBMIT) == 0) { |
1435 | mutex_exit(rpipe->pipe_lock); |
1436 | } |
1437 | return (1); |
1438 | } |
1439 | kn->kn_data = wpipe->pipe_buffer.size - wpipe->pipe_buffer.cnt; |
1440 | if (wpipe->pipe_state & PIPE_DIRECTW) |
1441 | kn->kn_data = 0; |
1442 | |
1443 | if ((hint & NOTE_SUBMIT) == 0) { |
1444 | mutex_exit(rpipe->pipe_lock); |
1445 | } |
1446 | return (kn->kn_data >= PIPE_BUF); |
1447 | } |
1448 | |
1449 | static const struct filterops pipe_rfiltops = |
1450 | { 1, NULL, filt_pipedetach, filt_piperead }; |
1451 | static const struct filterops pipe_wfiltops = |
1452 | { 1, NULL, filt_pipedetach, filt_pipewrite }; |
1453 | |
1454 | static int |
1455 | pipe_kqfilter(file_t *fp, struct knote *kn) |
1456 | { |
1457 | struct pipe *pipe; |
1458 | kmutex_t *lock; |
1459 | |
1460 | pipe = ((file_t *)kn->kn_obj)->f_pipe; |
1461 | lock = pipe->pipe_lock; |
1462 | |
1463 | mutex_enter(lock); |
1464 | |
1465 | switch (kn->kn_filter) { |
1466 | case EVFILT_READ: |
1467 | kn->kn_fop = &pipe_rfiltops; |
1468 | break; |
1469 | case EVFILT_WRITE: |
1470 | kn->kn_fop = &pipe_wfiltops; |
1471 | pipe = pipe->pipe_peer; |
1472 | if (pipe == NULL) { |
1473 | /* Other end of pipe has been closed. */ |
1474 | mutex_exit(lock); |
1475 | return (EBADF); |
1476 | } |
1477 | break; |
1478 | default: |
1479 | mutex_exit(lock); |
1480 | return (EINVAL); |
1481 | } |
1482 | |
1483 | kn->kn_hook = pipe; |
1484 | SLIST_INSERT_HEAD(&pipe->pipe_sel.sel_klist, kn, kn_selnext); |
1485 | mutex_exit(lock); |
1486 | |
1487 | return (0); |
1488 | } |
1489 | |
1490 | /* |
1491 | * Handle pipe sysctls. |
1492 | */ |
1493 | SYSCTL_SETUP(sysctl_kern_pipe_setup, "sysctl kern.pipe subtree setup" ) |
1494 | { |
1495 | |
1496 | sysctl_createv(clog, 0, NULL, NULL, |
1497 | CTLFLAG_PERMANENT, |
1498 | CTLTYPE_NODE, "pipe" , |
1499 | SYSCTL_DESCR("Pipe settings" ), |
1500 | NULL, 0, NULL, 0, |
1501 | CTL_KERN, KERN_PIPE, CTL_EOL); |
1502 | |
1503 | sysctl_createv(clog, 0, NULL, NULL, |
1504 | CTLFLAG_PERMANENT|CTLFLAG_READWRITE, |
1505 | CTLTYPE_INT, "maxkvasz" , |
1506 | SYSCTL_DESCR("Maximum amount of kernel memory to be " |
1507 | "used for pipes" ), |
1508 | NULL, 0, &maxpipekva, 0, |
1509 | CTL_KERN, KERN_PIPE, KERN_PIPE_MAXKVASZ, CTL_EOL); |
1510 | sysctl_createv(clog, 0, NULL, NULL, |
1511 | CTLFLAG_PERMANENT|CTLFLAG_READWRITE, |
1512 | CTLTYPE_INT, "maxloankvasz" , |
1513 | SYSCTL_DESCR("Limit for direct transfers via page loan" ), |
1514 | NULL, 0, &limitpipekva, 0, |
1515 | CTL_KERN, KERN_PIPE, KERN_PIPE_LIMITKVA, CTL_EOL); |
1516 | sysctl_createv(clog, 0, NULL, NULL, |
1517 | CTLFLAG_PERMANENT|CTLFLAG_READWRITE, |
1518 | CTLTYPE_INT, "maxbigpipes" , |
1519 | SYSCTL_DESCR("Maximum number of \"big\" pipes" ), |
1520 | NULL, 0, &maxbigpipes, 0, |
1521 | CTL_KERN, KERN_PIPE, KERN_PIPE_MAXBIGPIPES, CTL_EOL); |
1522 | sysctl_createv(clog, 0, NULL, NULL, |
1523 | CTLFLAG_PERMANENT, |
1524 | CTLTYPE_INT, "nbigpipes" , |
1525 | SYSCTL_DESCR("Number of \"big\" pipes" ), |
1526 | NULL, 0, &nbigpipe, 0, |
1527 | CTL_KERN, KERN_PIPE, KERN_PIPE_NBIGPIPES, CTL_EOL); |
1528 | sysctl_createv(clog, 0, NULL, NULL, |
1529 | CTLFLAG_PERMANENT, |
1530 | CTLTYPE_INT, "kvasize" , |
1531 | SYSCTL_DESCR("Amount of kernel memory consumed by pipe " |
1532 | "buffers" ), |
1533 | NULL, 0, &amountpipekva, 0, |
1534 | CTL_KERN, KERN_PIPE, KERN_PIPE_KVASIZE, CTL_EOL); |
1535 | } |
1536 | |