Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * linux/fs/pipe.c | |
3 | * | |
4 | * Copyright (C) 1991, 1992, 1999 Linus Torvalds | |
5 | */ | |
6 | ||
7 | #include <linux/mm.h> | |
8 | #include <linux/file.h> | |
9 | #include <linux/poll.h> | |
10 | #include <linux/slab.h> | |
11 | #include <linux/module.h> | |
12 | #include <linux/init.h> | |
13 | #include <linux/fs.h> | |
14 | #include <linux/mount.h> | |
15 | #include <linux/pipe_fs_i.h> | |
16 | #include <linux/uio.h> | |
17 | #include <linux/highmem.h> | |
5274f052 | 18 | #include <linux/pagemap.h> |
1da177e4 LT |
19 | |
20 | #include <asm/uaccess.h> | |
21 | #include <asm/ioctls.h> | |
22 | ||
23 | /* | |
24 | * We use a start+len construction, which provides full use of the | |
25 | * allocated memory. | |
26 | * -- Florian Coosmann (FGC) | |
27 | * | |
28 | * Reads with count = 0 should always return 0. | |
29 | * -- Julian Bradfield 1999-06-07. | |
30 | * | |
31 | * FIFOs and Pipes now generate SIGIO for both readers and writers. | |
32 | * -- Jeremy Elson <jelson@circlemud.org> 2001-08-16 | |
33 | * | |
34 | * pipe_read & write cleanup | |
35 | * -- Manfred Spraul <manfred@colorfullife.com> 2002-05-09 | |
36 | */ | |
37 | ||
38 | /* Drop the inode semaphore and wait for a pipe event, atomically */ | |
3a326a2c | 39 | void pipe_wait(struct pipe_inode_info *pipe) |
1da177e4 LT |
40 | { |
41 | DEFINE_WAIT(wait); | |
42 | ||
d79fc0fc IM |
43 | /* |
44 | * Pipes are system-local resources, so sleeping on them | |
45 | * is considered a noninteractive wait: | |
46 | */ | |
3a326a2c IM |
47 | prepare_to_wait(&pipe->wait, &wait, TASK_INTERRUPTIBLE|TASK_NONINTERACTIVE); |
48 | if (pipe->inode) | |
49 | mutex_unlock(&pipe->inode->i_mutex); | |
1da177e4 | 50 | schedule(); |
3a326a2c IM |
51 | finish_wait(&pipe->wait, &wait); |
52 | if (pipe->inode) | |
53 | mutex_lock(&pipe->inode->i_mutex); | |
1da177e4 LT |
54 | } |
55 | ||
858119e1 | 56 | static int |
1da177e4 LT |
57 | pipe_iov_copy_from_user(void *to, struct iovec *iov, unsigned long len) |
58 | { | |
59 | unsigned long copy; | |
60 | ||
61 | while (len > 0) { | |
62 | while (!iov->iov_len) | |
63 | iov++; | |
64 | copy = min_t(unsigned long, len, iov->iov_len); | |
65 | ||
66 | if (copy_from_user(to, iov->iov_base, copy)) | |
67 | return -EFAULT; | |
68 | to += copy; | |
69 | len -= copy; | |
70 | iov->iov_base += copy; | |
71 | iov->iov_len -= copy; | |
72 | } | |
73 | return 0; | |
74 | } | |
75 | ||
858119e1 | 76 | static int |
1da177e4 LT |
77 | pipe_iov_copy_to_user(struct iovec *iov, const void *from, unsigned long len) |
78 | { | |
79 | unsigned long copy; | |
80 | ||
81 | while (len > 0) { | |
82 | while (!iov->iov_len) | |
83 | iov++; | |
84 | copy = min_t(unsigned long, len, iov->iov_len); | |
85 | ||
86 | if (copy_to_user(iov->iov_base, from, copy)) | |
87 | return -EFAULT; | |
88 | from += copy; | |
89 | len -= copy; | |
90 | iov->iov_base += copy; | |
91 | iov->iov_len -= copy; | |
92 | } | |
93 | return 0; | |
94 | } | |
95 | ||
96 | static void anon_pipe_buf_release(struct pipe_inode_info *info, struct pipe_buffer *buf) | |
97 | { | |
98 | struct page *page = buf->page; | |
99 | ||
3e7ee3e7 JA |
100 | buf->flags &= ~PIPE_BUF_FLAG_STOLEN; |
101 | ||
5274f052 JA |
102 | /* |
103 | * If nobody else uses this page, and we don't already have a | |
104 | * temporary page, let's keep track of it as a one-deep | |
105 | * allocation cache | |
106 | */ | |
107 | if (page_count(page) == 1 && !info->tmp_page) { | |
108 | info->tmp_page = page; | |
1da177e4 LT |
109 | return; |
110 | } | |
5274f052 JA |
111 | |
112 | /* | |
113 | * Otherwise just release our reference to it | |
114 | */ | |
115 | page_cache_release(page); | |
1da177e4 LT |
116 | } |
117 | ||
118 | static void *anon_pipe_buf_map(struct file *file, struct pipe_inode_info *info, struct pipe_buffer *buf) | |
119 | { | |
120 | return kmap(buf->page); | |
121 | } | |
122 | ||
123 | static void anon_pipe_buf_unmap(struct pipe_inode_info *info, struct pipe_buffer *buf) | |
124 | { | |
125 | kunmap(buf->page); | |
126 | } | |
127 | ||
5abc97aa JA |
128 | static int anon_pipe_buf_steal(struct pipe_inode_info *info, |
129 | struct pipe_buffer *buf) | |
130 | { | |
3e7ee3e7 | 131 | buf->flags |= PIPE_BUF_FLAG_STOLEN; |
5abc97aa JA |
132 | return 0; |
133 | } | |
134 | ||
1da177e4 LT |
135 | static struct pipe_buf_operations anon_pipe_buf_ops = { |
136 | .can_merge = 1, | |
137 | .map = anon_pipe_buf_map, | |
138 | .unmap = anon_pipe_buf_unmap, | |
139 | .release = anon_pipe_buf_release, | |
5abc97aa | 140 | .steal = anon_pipe_buf_steal, |
1da177e4 LT |
141 | }; |
142 | ||
143 | static ssize_t | |
144 | pipe_readv(struct file *filp, const struct iovec *_iov, | |
145 | unsigned long nr_segs, loff_t *ppos) | |
146 | { | |
147 | struct inode *inode = filp->f_dentry->d_inode; | |
148 | struct pipe_inode_info *info; | |
149 | int do_wakeup; | |
150 | ssize_t ret; | |
151 | struct iovec *iov = (struct iovec *)_iov; | |
152 | size_t total_len; | |
153 | ||
154 | total_len = iov_length(iov, nr_segs); | |
155 | /* Null read succeeds. */ | |
156 | if (unlikely(total_len == 0)) | |
157 | return 0; | |
158 | ||
159 | do_wakeup = 0; | |
160 | ret = 0; | |
1b1dcc1b | 161 | mutex_lock(PIPE_MUTEX(*inode)); |
1da177e4 LT |
162 | info = inode->i_pipe; |
163 | for (;;) { | |
164 | int bufs = info->nrbufs; | |
165 | if (bufs) { | |
166 | int curbuf = info->curbuf; | |
167 | struct pipe_buffer *buf = info->bufs + curbuf; | |
168 | struct pipe_buf_operations *ops = buf->ops; | |
169 | void *addr; | |
170 | size_t chars = buf->len; | |
171 | int error; | |
172 | ||
173 | if (chars > total_len) | |
174 | chars = total_len; | |
175 | ||
176 | addr = ops->map(filp, info, buf); | |
5274f052 JA |
177 | if (IS_ERR(addr)) { |
178 | if (!ret) | |
179 | ret = PTR_ERR(addr); | |
180 | break; | |
181 | } | |
1da177e4 LT |
182 | error = pipe_iov_copy_to_user(iov, addr + buf->offset, chars); |
183 | ops->unmap(info, buf); | |
184 | if (unlikely(error)) { | |
185 | if (!ret) ret = -EFAULT; | |
186 | break; | |
187 | } | |
188 | ret += chars; | |
189 | buf->offset += chars; | |
190 | buf->len -= chars; | |
191 | if (!buf->len) { | |
192 | buf->ops = NULL; | |
193 | ops->release(info, buf); | |
194 | curbuf = (curbuf + 1) & (PIPE_BUFFERS-1); | |
195 | info->curbuf = curbuf; | |
196 | info->nrbufs = --bufs; | |
197 | do_wakeup = 1; | |
198 | } | |
199 | total_len -= chars; | |
200 | if (!total_len) | |
201 | break; /* common path: read succeeded */ | |
202 | } | |
203 | if (bufs) /* More to do? */ | |
204 | continue; | |
205 | if (!PIPE_WRITERS(*inode)) | |
206 | break; | |
207 | if (!PIPE_WAITING_WRITERS(*inode)) { | |
208 | /* syscall merging: Usually we must not sleep | |
209 | * if O_NONBLOCK is set, or if we got some data. | |
210 | * But if a writer sleeps in kernel space, then | |
211 | * we can wait for that data without violating POSIX. | |
212 | */ | |
213 | if (ret) | |
214 | break; | |
215 | if (filp->f_flags & O_NONBLOCK) { | |
216 | ret = -EAGAIN; | |
217 | break; | |
218 | } | |
219 | } | |
220 | if (signal_pending(current)) { | |
221 | if (!ret) ret = -ERESTARTSYS; | |
222 | break; | |
223 | } | |
224 | if (do_wakeup) { | |
225 | wake_up_interruptible_sync(PIPE_WAIT(*inode)); | |
226 | kill_fasync(PIPE_FASYNC_WRITERS(*inode), SIGIO, POLL_OUT); | |
227 | } | |
3a326a2c | 228 | pipe_wait(inode->i_pipe); |
1da177e4 | 229 | } |
1b1dcc1b | 230 | mutex_unlock(PIPE_MUTEX(*inode)); |
1da177e4 LT |
231 | /* Signal writers asynchronously that there is more room. */ |
232 | if (do_wakeup) { | |
233 | wake_up_interruptible(PIPE_WAIT(*inode)); | |
234 | kill_fasync(PIPE_FASYNC_WRITERS(*inode), SIGIO, POLL_OUT); | |
235 | } | |
236 | if (ret > 0) | |
237 | file_accessed(filp); | |
238 | return ret; | |
239 | } | |
240 | ||
241 | static ssize_t | |
242 | pipe_read(struct file *filp, char __user *buf, size_t count, loff_t *ppos) | |
243 | { | |
244 | struct iovec iov = { .iov_base = buf, .iov_len = count }; | |
245 | return pipe_readv(filp, &iov, 1, ppos); | |
246 | } | |
247 | ||
248 | static ssize_t | |
249 | pipe_writev(struct file *filp, const struct iovec *_iov, | |
250 | unsigned long nr_segs, loff_t *ppos) | |
251 | { | |
252 | struct inode *inode = filp->f_dentry->d_inode; | |
253 | struct pipe_inode_info *info; | |
254 | ssize_t ret; | |
255 | int do_wakeup; | |
256 | struct iovec *iov = (struct iovec *)_iov; | |
257 | size_t total_len; | |
258 | ssize_t chars; | |
259 | ||
260 | total_len = iov_length(iov, nr_segs); | |
261 | /* Null write succeeds. */ | |
262 | if (unlikely(total_len == 0)) | |
263 | return 0; | |
264 | ||
265 | do_wakeup = 0; | |
266 | ret = 0; | |
1b1dcc1b | 267 | mutex_lock(PIPE_MUTEX(*inode)); |
1da177e4 LT |
268 | info = inode->i_pipe; |
269 | ||
270 | if (!PIPE_READERS(*inode)) { | |
271 | send_sig(SIGPIPE, current, 0); | |
272 | ret = -EPIPE; | |
273 | goto out; | |
274 | } | |
275 | ||
276 | /* We try to merge small writes */ | |
277 | chars = total_len & (PAGE_SIZE-1); /* size of the last buffer */ | |
278 | if (info->nrbufs && chars != 0) { | |
279 | int lastbuf = (info->curbuf + info->nrbufs - 1) & (PIPE_BUFFERS-1); | |
280 | struct pipe_buffer *buf = info->bufs + lastbuf; | |
281 | struct pipe_buf_operations *ops = buf->ops; | |
282 | int offset = buf->offset + buf->len; | |
283 | if (ops->can_merge && offset + chars <= PAGE_SIZE) { | |
5274f052 JA |
284 | void *addr; |
285 | int error; | |
286 | ||
287 | addr = ops->map(filp, info, buf); | |
288 | if (IS_ERR(addr)) { | |
289 | error = PTR_ERR(addr); | |
290 | goto out; | |
291 | } | |
292 | error = pipe_iov_copy_from_user(offset + addr, iov, | |
293 | chars); | |
1da177e4 LT |
294 | ops->unmap(info, buf); |
295 | ret = error; | |
296 | do_wakeup = 1; | |
297 | if (error) | |
298 | goto out; | |
299 | buf->len += chars; | |
300 | total_len -= chars; | |
301 | ret = chars; | |
302 | if (!total_len) | |
303 | goto out; | |
304 | } | |
305 | } | |
306 | ||
307 | for (;;) { | |
308 | int bufs; | |
309 | if (!PIPE_READERS(*inode)) { | |
310 | send_sig(SIGPIPE, current, 0); | |
311 | if (!ret) ret = -EPIPE; | |
312 | break; | |
313 | } | |
314 | bufs = info->nrbufs; | |
315 | if (bufs < PIPE_BUFFERS) { | |
316 | int newbuf = (info->curbuf + bufs) & (PIPE_BUFFERS-1); | |
317 | struct pipe_buffer *buf = info->bufs + newbuf; | |
318 | struct page *page = info->tmp_page; | |
319 | int error; | |
320 | ||
321 | if (!page) { | |
322 | page = alloc_page(GFP_HIGHUSER); | |
323 | if (unlikely(!page)) { | |
324 | ret = ret ? : -ENOMEM; | |
325 | break; | |
326 | } | |
327 | info->tmp_page = page; | |
328 | } | |
329 | /* Always wakeup, even if the copy fails. Otherwise | |
330 | * we lock up (O_NONBLOCK-)readers that sleep due to | |
331 | * syscall merging. | |
332 | * FIXME! Is this really true? | |
333 | */ | |
334 | do_wakeup = 1; | |
335 | chars = PAGE_SIZE; | |
336 | if (chars > total_len) | |
337 | chars = total_len; | |
338 | ||
339 | error = pipe_iov_copy_from_user(kmap(page), iov, chars); | |
340 | kunmap(page); | |
341 | if (unlikely(error)) { | |
342 | if (!ret) ret = -EFAULT; | |
343 | break; | |
344 | } | |
345 | ret += chars; | |
346 | ||
347 | /* Insert it into the buffer array */ | |
348 | buf->page = page; | |
349 | buf->ops = &anon_pipe_buf_ops; | |
350 | buf->offset = 0; | |
351 | buf->len = chars; | |
352 | info->nrbufs = ++bufs; | |
353 | info->tmp_page = NULL; | |
354 | ||
355 | total_len -= chars; | |
356 | if (!total_len) | |
357 | break; | |
358 | } | |
359 | if (bufs < PIPE_BUFFERS) | |
360 | continue; | |
361 | if (filp->f_flags & O_NONBLOCK) { | |
362 | if (!ret) ret = -EAGAIN; | |
363 | break; | |
364 | } | |
365 | if (signal_pending(current)) { | |
366 | if (!ret) ret = -ERESTARTSYS; | |
367 | break; | |
368 | } | |
369 | if (do_wakeup) { | |
370 | wake_up_interruptible_sync(PIPE_WAIT(*inode)); | |
371 | kill_fasync(PIPE_FASYNC_READERS(*inode), SIGIO, POLL_IN); | |
372 | do_wakeup = 0; | |
373 | } | |
374 | PIPE_WAITING_WRITERS(*inode)++; | |
3a326a2c | 375 | pipe_wait(inode->i_pipe); |
1da177e4 LT |
376 | PIPE_WAITING_WRITERS(*inode)--; |
377 | } | |
378 | out: | |
1b1dcc1b | 379 | mutex_unlock(PIPE_MUTEX(*inode)); |
1da177e4 LT |
380 | if (do_wakeup) { |
381 | wake_up_interruptible(PIPE_WAIT(*inode)); | |
382 | kill_fasync(PIPE_FASYNC_READERS(*inode), SIGIO, POLL_IN); | |
383 | } | |
384 | if (ret > 0) | |
870f4817 | 385 | file_update_time(filp); |
1da177e4 LT |
386 | return ret; |
387 | } | |
388 | ||
389 | static ssize_t | |
390 | pipe_write(struct file *filp, const char __user *buf, | |
391 | size_t count, loff_t *ppos) | |
392 | { | |
393 | struct iovec iov = { .iov_base = (void __user *)buf, .iov_len = count }; | |
394 | return pipe_writev(filp, &iov, 1, ppos); | |
395 | } | |
396 | ||
397 | static ssize_t | |
398 | bad_pipe_r(struct file *filp, char __user *buf, size_t count, loff_t *ppos) | |
399 | { | |
400 | return -EBADF; | |
401 | } | |
402 | ||
403 | static ssize_t | |
404 | bad_pipe_w(struct file *filp, const char __user *buf, size_t count, loff_t *ppos) | |
405 | { | |
406 | return -EBADF; | |
407 | } | |
408 | ||
409 | static int | |
410 | pipe_ioctl(struct inode *pino, struct file *filp, | |
411 | unsigned int cmd, unsigned long arg) | |
412 | { | |
413 | struct inode *inode = filp->f_dentry->d_inode; | |
414 | struct pipe_inode_info *info; | |
415 | int count, buf, nrbufs; | |
416 | ||
417 | switch (cmd) { | |
418 | case FIONREAD: | |
1b1dcc1b | 419 | mutex_lock(PIPE_MUTEX(*inode)); |
1da177e4 LT |
420 | info = inode->i_pipe; |
421 | count = 0; | |
422 | buf = info->curbuf; | |
423 | nrbufs = info->nrbufs; | |
424 | while (--nrbufs >= 0) { | |
425 | count += info->bufs[buf].len; | |
426 | buf = (buf+1) & (PIPE_BUFFERS-1); | |
427 | } | |
1b1dcc1b | 428 | mutex_unlock(PIPE_MUTEX(*inode)); |
1da177e4 LT |
429 | return put_user(count, (int __user *)arg); |
430 | default: | |
431 | return -EINVAL; | |
432 | } | |
433 | } | |
434 | ||
435 | /* No kernel lock held - fine */ | |
436 | static unsigned int | |
437 | pipe_poll(struct file *filp, poll_table *wait) | |
438 | { | |
439 | unsigned int mask; | |
440 | struct inode *inode = filp->f_dentry->d_inode; | |
441 | struct pipe_inode_info *info = inode->i_pipe; | |
442 | int nrbufs; | |
443 | ||
444 | poll_wait(filp, PIPE_WAIT(*inode), wait); | |
445 | ||
446 | /* Reading only -- no need for acquiring the semaphore. */ | |
447 | nrbufs = info->nrbufs; | |
448 | mask = 0; | |
449 | if (filp->f_mode & FMODE_READ) { | |
450 | mask = (nrbufs > 0) ? POLLIN | POLLRDNORM : 0; | |
451 | if (!PIPE_WRITERS(*inode) && filp->f_version != PIPE_WCOUNTER(*inode)) | |
452 | mask |= POLLHUP; | |
453 | } | |
454 | ||
455 | if (filp->f_mode & FMODE_WRITE) { | |
456 | mask |= (nrbufs < PIPE_BUFFERS) ? POLLOUT | POLLWRNORM : 0; | |
5e5d7a22 PE |
457 | /* |
458 | * Most Unices do not set POLLERR for FIFOs but on Linux they | |
459 | * behave exactly like pipes for poll(). | |
460 | */ | |
1da177e4 LT |
461 | if (!PIPE_READERS(*inode)) |
462 | mask |= POLLERR; | |
463 | } | |
464 | ||
465 | return mask; | |
466 | } | |
467 | ||
1da177e4 LT |
468 | static int |
469 | pipe_release(struct inode *inode, int decr, int decw) | |
470 | { | |
1b1dcc1b | 471 | mutex_lock(PIPE_MUTEX(*inode)); |
1da177e4 LT |
472 | PIPE_READERS(*inode) -= decr; |
473 | PIPE_WRITERS(*inode) -= decw; | |
474 | if (!PIPE_READERS(*inode) && !PIPE_WRITERS(*inode)) { | |
475 | free_pipe_info(inode); | |
476 | } else { | |
477 | wake_up_interruptible(PIPE_WAIT(*inode)); | |
478 | kill_fasync(PIPE_FASYNC_READERS(*inode), SIGIO, POLL_IN); | |
479 | kill_fasync(PIPE_FASYNC_WRITERS(*inode), SIGIO, POLL_OUT); | |
480 | } | |
1b1dcc1b | 481 | mutex_unlock(PIPE_MUTEX(*inode)); |
1da177e4 LT |
482 | |
483 | return 0; | |
484 | } | |
485 | ||
486 | static int | |
487 | pipe_read_fasync(int fd, struct file *filp, int on) | |
488 | { | |
489 | struct inode *inode = filp->f_dentry->d_inode; | |
490 | int retval; | |
491 | ||
1b1dcc1b | 492 | mutex_lock(PIPE_MUTEX(*inode)); |
1da177e4 | 493 | retval = fasync_helper(fd, filp, on, PIPE_FASYNC_READERS(*inode)); |
1b1dcc1b | 494 | mutex_unlock(PIPE_MUTEX(*inode)); |
1da177e4 LT |
495 | |
496 | if (retval < 0) | |
497 | return retval; | |
498 | ||
499 | return 0; | |
500 | } | |
501 | ||
502 | ||
503 | static int | |
504 | pipe_write_fasync(int fd, struct file *filp, int on) | |
505 | { | |
506 | struct inode *inode = filp->f_dentry->d_inode; | |
507 | int retval; | |
508 | ||
1b1dcc1b | 509 | mutex_lock(PIPE_MUTEX(*inode)); |
1da177e4 | 510 | retval = fasync_helper(fd, filp, on, PIPE_FASYNC_WRITERS(*inode)); |
1b1dcc1b | 511 | mutex_unlock(PIPE_MUTEX(*inode)); |
1da177e4 LT |
512 | |
513 | if (retval < 0) | |
514 | return retval; | |
515 | ||
516 | return 0; | |
517 | } | |
518 | ||
519 | ||
520 | static int | |
521 | pipe_rdwr_fasync(int fd, struct file *filp, int on) | |
522 | { | |
523 | struct inode *inode = filp->f_dentry->d_inode; | |
524 | int retval; | |
525 | ||
1b1dcc1b | 526 | mutex_lock(PIPE_MUTEX(*inode)); |
1da177e4 LT |
527 | |
528 | retval = fasync_helper(fd, filp, on, PIPE_FASYNC_READERS(*inode)); | |
529 | ||
530 | if (retval >= 0) | |
531 | retval = fasync_helper(fd, filp, on, PIPE_FASYNC_WRITERS(*inode)); | |
532 | ||
1b1dcc1b | 533 | mutex_unlock(PIPE_MUTEX(*inode)); |
1da177e4 LT |
534 | |
535 | if (retval < 0) | |
536 | return retval; | |
537 | ||
538 | return 0; | |
539 | } | |
540 | ||
541 | ||
542 | static int | |
543 | pipe_read_release(struct inode *inode, struct file *filp) | |
544 | { | |
545 | pipe_read_fasync(-1, filp, 0); | |
546 | return pipe_release(inode, 1, 0); | |
547 | } | |
548 | ||
549 | static int | |
550 | pipe_write_release(struct inode *inode, struct file *filp) | |
551 | { | |
552 | pipe_write_fasync(-1, filp, 0); | |
553 | return pipe_release(inode, 0, 1); | |
554 | } | |
555 | ||
556 | static int | |
557 | pipe_rdwr_release(struct inode *inode, struct file *filp) | |
558 | { | |
559 | int decr, decw; | |
560 | ||
561 | pipe_rdwr_fasync(-1, filp, 0); | |
562 | decr = (filp->f_mode & FMODE_READ) != 0; | |
563 | decw = (filp->f_mode & FMODE_WRITE) != 0; | |
564 | return pipe_release(inode, decr, decw); | |
565 | } | |
566 | ||
567 | static int | |
568 | pipe_read_open(struct inode *inode, struct file *filp) | |
569 | { | |
570 | /* We could have perhaps used atomic_t, but this and friends | |
571 | below are the only places. So it doesn't seem worthwhile. */ | |
1b1dcc1b | 572 | mutex_lock(PIPE_MUTEX(*inode)); |
1da177e4 | 573 | PIPE_READERS(*inode)++; |
1b1dcc1b | 574 | mutex_unlock(PIPE_MUTEX(*inode)); |
1da177e4 LT |
575 | |
576 | return 0; | |
577 | } | |
578 | ||
579 | static int | |
580 | pipe_write_open(struct inode *inode, struct file *filp) | |
581 | { | |
1b1dcc1b | 582 | mutex_lock(PIPE_MUTEX(*inode)); |
1da177e4 | 583 | PIPE_WRITERS(*inode)++; |
1b1dcc1b | 584 | mutex_unlock(PIPE_MUTEX(*inode)); |
1da177e4 LT |
585 | |
586 | return 0; | |
587 | } | |
588 | ||
589 | static int | |
590 | pipe_rdwr_open(struct inode *inode, struct file *filp) | |
591 | { | |
1b1dcc1b | 592 | mutex_lock(PIPE_MUTEX(*inode)); |
1da177e4 LT |
593 | if (filp->f_mode & FMODE_READ) |
594 | PIPE_READERS(*inode)++; | |
595 | if (filp->f_mode & FMODE_WRITE) | |
596 | PIPE_WRITERS(*inode)++; | |
1b1dcc1b | 597 | mutex_unlock(PIPE_MUTEX(*inode)); |
1da177e4 LT |
598 | |
599 | return 0; | |
600 | } | |
601 | ||
602 | /* | |
603 | * The file_operations structs are not static because they | |
604 | * are also used in linux/fs/fifo.c to do operations on FIFOs. | |
605 | */ | |
4b6f5d20 | 606 | const struct file_operations read_fifo_fops = { |
1da177e4 LT |
607 | .llseek = no_llseek, |
608 | .read = pipe_read, | |
609 | .readv = pipe_readv, | |
610 | .write = bad_pipe_w, | |
5e5d7a22 | 611 | .poll = pipe_poll, |
1da177e4 LT |
612 | .ioctl = pipe_ioctl, |
613 | .open = pipe_read_open, | |
614 | .release = pipe_read_release, | |
615 | .fasync = pipe_read_fasync, | |
616 | }; | |
617 | ||
4b6f5d20 | 618 | const struct file_operations write_fifo_fops = { |
1da177e4 LT |
619 | .llseek = no_llseek, |
620 | .read = bad_pipe_r, | |
621 | .write = pipe_write, | |
622 | .writev = pipe_writev, | |
5e5d7a22 | 623 | .poll = pipe_poll, |
1da177e4 LT |
624 | .ioctl = pipe_ioctl, |
625 | .open = pipe_write_open, | |
626 | .release = pipe_write_release, | |
627 | .fasync = pipe_write_fasync, | |
628 | }; | |
629 | ||
4b6f5d20 | 630 | const struct file_operations rdwr_fifo_fops = { |
1da177e4 LT |
631 | .llseek = no_llseek, |
632 | .read = pipe_read, | |
633 | .readv = pipe_readv, | |
634 | .write = pipe_write, | |
635 | .writev = pipe_writev, | |
5e5d7a22 | 636 | .poll = pipe_poll, |
1da177e4 LT |
637 | .ioctl = pipe_ioctl, |
638 | .open = pipe_rdwr_open, | |
639 | .release = pipe_rdwr_release, | |
640 | .fasync = pipe_rdwr_fasync, | |
641 | }; | |
642 | ||
a19cbd4b | 643 | static struct file_operations read_pipe_fops = { |
1da177e4 LT |
644 | .llseek = no_llseek, |
645 | .read = pipe_read, | |
646 | .readv = pipe_readv, | |
647 | .write = bad_pipe_w, | |
648 | .poll = pipe_poll, | |
649 | .ioctl = pipe_ioctl, | |
650 | .open = pipe_read_open, | |
651 | .release = pipe_read_release, | |
652 | .fasync = pipe_read_fasync, | |
653 | }; | |
654 | ||
a19cbd4b | 655 | static struct file_operations write_pipe_fops = { |
1da177e4 LT |
656 | .llseek = no_llseek, |
657 | .read = bad_pipe_r, | |
658 | .write = pipe_write, | |
659 | .writev = pipe_writev, | |
660 | .poll = pipe_poll, | |
661 | .ioctl = pipe_ioctl, | |
662 | .open = pipe_write_open, | |
663 | .release = pipe_write_release, | |
664 | .fasync = pipe_write_fasync, | |
665 | }; | |
666 | ||
a19cbd4b | 667 | static struct file_operations rdwr_pipe_fops = { |
1da177e4 LT |
668 | .llseek = no_llseek, |
669 | .read = pipe_read, | |
670 | .readv = pipe_readv, | |
671 | .write = pipe_write, | |
672 | .writev = pipe_writev, | |
673 | .poll = pipe_poll, | |
674 | .ioctl = pipe_ioctl, | |
675 | .open = pipe_rdwr_open, | |
676 | .release = pipe_rdwr_release, | |
677 | .fasync = pipe_rdwr_fasync, | |
678 | }; | |
679 | ||
3a326a2c IM |
680 | struct pipe_inode_info * alloc_pipe_info(struct inode *inode) |
681 | { | |
682 | struct pipe_inode_info *info; | |
683 | ||
684 | info = kzalloc(sizeof(struct pipe_inode_info), GFP_KERNEL); | |
685 | if (info) { | |
686 | init_waitqueue_head(&info->wait); | |
687 | info->r_counter = info->w_counter = 1; | |
688 | info->inode = inode; | |
689 | } | |
690 | ||
691 | return info; | |
692 | } | |
693 | ||
1da177e4 LT |
694 | void free_pipe_info(struct inode *inode) |
695 | { | |
696 | int i; | |
697 | struct pipe_inode_info *info = inode->i_pipe; | |
698 | ||
699 | inode->i_pipe = NULL; | |
700 | for (i = 0; i < PIPE_BUFFERS; i++) { | |
701 | struct pipe_buffer *buf = info->bufs + i; | |
702 | if (buf->ops) | |
703 | buf->ops->release(info, buf); | |
704 | } | |
705 | if (info->tmp_page) | |
706 | __free_page(info->tmp_page); | |
707 | kfree(info); | |
708 | } | |
709 | ||
fa3536cc | 710 | static struct vfsmount *pipe_mnt __read_mostly; |
1da177e4 LT |
711 | static int pipefs_delete_dentry(struct dentry *dentry) |
712 | { | |
713 | return 1; | |
714 | } | |
715 | static struct dentry_operations pipefs_dentry_operations = { | |
716 | .d_delete = pipefs_delete_dentry, | |
717 | }; | |
718 | ||
719 | static struct inode * get_pipe_inode(void) | |
720 | { | |
721 | struct inode *inode = new_inode(pipe_mnt->mnt_sb); | |
722 | ||
723 | if (!inode) | |
724 | goto fail_inode; | |
725 | ||
3a326a2c IM |
726 | inode->i_pipe = alloc_pipe_info(inode); |
727 | if (!inode->i_pipe) | |
1da177e4 | 728 | goto fail_iput; |
3a326a2c | 729 | |
1da177e4 LT |
730 | PIPE_READERS(*inode) = PIPE_WRITERS(*inode) = 1; |
731 | inode->i_fop = &rdwr_pipe_fops; | |
732 | ||
733 | /* | |
734 | * Mark the inode dirty from the very beginning, | |
735 | * that way it will never be moved to the dirty | |
736 | * list because "mark_inode_dirty()" will think | |
737 | * that it already _is_ on the dirty list. | |
738 | */ | |
739 | inode->i_state = I_DIRTY; | |
740 | inode->i_mode = S_IFIFO | S_IRUSR | S_IWUSR; | |
741 | inode->i_uid = current->fsuid; | |
742 | inode->i_gid = current->fsgid; | |
743 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; | |
744 | inode->i_blksize = PAGE_SIZE; | |
745 | return inode; | |
746 | ||
747 | fail_iput: | |
748 | iput(inode); | |
749 | fail_inode: | |
750 | return NULL; | |
751 | } | |
752 | ||
753 | int do_pipe(int *fd) | |
754 | { | |
755 | struct qstr this; | |
756 | char name[32]; | |
757 | struct dentry *dentry; | |
758 | struct inode * inode; | |
759 | struct file *f1, *f2; | |
760 | int error; | |
761 | int i,j; | |
762 | ||
763 | error = -ENFILE; | |
764 | f1 = get_empty_filp(); | |
765 | if (!f1) | |
766 | goto no_files; | |
767 | ||
768 | f2 = get_empty_filp(); | |
769 | if (!f2) | |
770 | goto close_f1; | |
771 | ||
772 | inode = get_pipe_inode(); | |
773 | if (!inode) | |
774 | goto close_f12; | |
775 | ||
776 | error = get_unused_fd(); | |
777 | if (error < 0) | |
778 | goto close_f12_inode; | |
779 | i = error; | |
780 | ||
781 | error = get_unused_fd(); | |
782 | if (error < 0) | |
783 | goto close_f12_inode_i; | |
784 | j = error; | |
785 | ||
786 | error = -ENOMEM; | |
787 | sprintf(name, "[%lu]", inode->i_ino); | |
788 | this.name = name; | |
789 | this.len = strlen(name); | |
790 | this.hash = inode->i_ino; /* will go */ | |
791 | dentry = d_alloc(pipe_mnt->mnt_sb->s_root, &this); | |
792 | if (!dentry) | |
793 | goto close_f12_inode_i_j; | |
794 | dentry->d_op = &pipefs_dentry_operations; | |
795 | d_add(dentry, inode); | |
796 | f1->f_vfsmnt = f2->f_vfsmnt = mntget(mntget(pipe_mnt)); | |
797 | f1->f_dentry = f2->f_dentry = dget(dentry); | |
798 | f1->f_mapping = f2->f_mapping = inode->i_mapping; | |
799 | ||
800 | /* read file */ | |
801 | f1->f_pos = f2->f_pos = 0; | |
802 | f1->f_flags = O_RDONLY; | |
803 | f1->f_op = &read_pipe_fops; | |
804 | f1->f_mode = FMODE_READ; | |
805 | f1->f_version = 0; | |
806 | ||
807 | /* write file */ | |
808 | f2->f_flags = O_WRONLY; | |
809 | f2->f_op = &write_pipe_fops; | |
810 | f2->f_mode = FMODE_WRITE; | |
811 | f2->f_version = 0; | |
812 | ||
813 | fd_install(i, f1); | |
814 | fd_install(j, f2); | |
815 | fd[0] = i; | |
816 | fd[1] = j; | |
817 | return 0; | |
818 | ||
819 | close_f12_inode_i_j: | |
820 | put_unused_fd(j); | |
821 | close_f12_inode_i: | |
822 | put_unused_fd(i); | |
823 | close_f12_inode: | |
824 | free_pipe_info(inode); | |
825 | iput(inode); | |
826 | close_f12: | |
827 | put_filp(f2); | |
828 | close_f1: | |
829 | put_filp(f1); | |
830 | no_files: | |
831 | return error; | |
832 | } | |
833 | ||
834 | /* | |
835 | * pipefs should _never_ be mounted by userland - too much of security hassle, | |
836 | * no real gain from having the whole whorehouse mounted. So we don't need | |
837 | * any operations on the root directory. However, we need a non-trivial | |
838 | * d_name - pipe: will go nicely and kill the special-casing in procfs. | |
839 | */ | |
840 | ||
841 | static struct super_block *pipefs_get_sb(struct file_system_type *fs_type, | |
842 | int flags, const char *dev_name, void *data) | |
843 | { | |
844 | return get_sb_pseudo(fs_type, "pipe:", NULL, PIPEFS_MAGIC); | |
845 | } | |
846 | ||
847 | static struct file_system_type pipe_fs_type = { | |
848 | .name = "pipefs", | |
849 | .get_sb = pipefs_get_sb, | |
850 | .kill_sb = kill_anon_super, | |
851 | }; | |
852 | ||
853 | static int __init init_pipe_fs(void) | |
854 | { | |
855 | int err = register_filesystem(&pipe_fs_type); | |
856 | if (!err) { | |
857 | pipe_mnt = kern_mount(&pipe_fs_type); | |
858 | if (IS_ERR(pipe_mnt)) { | |
859 | err = PTR_ERR(pipe_mnt); | |
860 | unregister_filesystem(&pipe_fs_type); | |
861 | } | |
862 | } | |
863 | return err; | |
864 | } | |
865 | ||
866 | static void __exit exit_pipe_fs(void) | |
867 | { | |
868 | unregister_filesystem(&pipe_fs_type); | |
869 | mntput(pipe_mnt); | |
870 | } | |
871 | ||
872 | fs_initcall(init_pipe_fs); | |
873 | module_exit(exit_pipe_fs); |