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 */ | |
39 | void pipe_wait(struct inode * inode) | |
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 | */ | |
47 | prepare_to_wait(PIPE_WAIT(*inode), &wait, TASK_INTERRUPTIBLE|TASK_NONINTERACTIVE); | |
1b1dcc1b | 48 | mutex_unlock(PIPE_MUTEX(*inode)); |
1da177e4 LT |
49 | schedule(); |
50 | finish_wait(PIPE_WAIT(*inode), &wait); | |
1b1dcc1b | 51 | mutex_lock(PIPE_MUTEX(*inode)); |
1da177e4 LT |
52 | } |
53 | ||
858119e1 | 54 | static int |
1da177e4 LT |
55 | pipe_iov_copy_from_user(void *to, struct iovec *iov, unsigned long len) |
56 | { | |
57 | unsigned long copy; | |
58 | ||
59 | while (len > 0) { | |
60 | while (!iov->iov_len) | |
61 | iov++; | |
62 | copy = min_t(unsigned long, len, iov->iov_len); | |
63 | ||
64 | if (copy_from_user(to, iov->iov_base, copy)) | |
65 | return -EFAULT; | |
66 | to += copy; | |
67 | len -= copy; | |
68 | iov->iov_base += copy; | |
69 | iov->iov_len -= copy; | |
70 | } | |
71 | return 0; | |
72 | } | |
73 | ||
858119e1 | 74 | static int |
1da177e4 LT |
75 | pipe_iov_copy_to_user(struct iovec *iov, const void *from, unsigned long len) |
76 | { | |
77 | unsigned long copy; | |
78 | ||
79 | while (len > 0) { | |
80 | while (!iov->iov_len) | |
81 | iov++; | |
82 | copy = min_t(unsigned long, len, iov->iov_len); | |
83 | ||
84 | if (copy_to_user(iov->iov_base, from, copy)) | |
85 | return -EFAULT; | |
86 | from += copy; | |
87 | len -= copy; | |
88 | iov->iov_base += copy; | |
89 | iov->iov_len -= copy; | |
90 | } | |
91 | return 0; | |
92 | } | |
93 | ||
94 | static void anon_pipe_buf_release(struct pipe_inode_info *info, struct pipe_buffer *buf) | |
95 | { | |
96 | struct page *page = buf->page; | |
97 | ||
5274f052 JA |
98 | /* |
99 | * If nobody else uses this page, and we don't already have a | |
100 | * temporary page, let's keep track of it as a one-deep | |
101 | * allocation cache | |
102 | */ | |
103 | if (page_count(page) == 1 && !info->tmp_page) { | |
104 | info->tmp_page = page; | |
1da177e4 LT |
105 | return; |
106 | } | |
5274f052 JA |
107 | |
108 | /* | |
109 | * Otherwise just release our reference to it | |
110 | */ | |
111 | page_cache_release(page); | |
1da177e4 LT |
112 | } |
113 | ||
114 | static void *anon_pipe_buf_map(struct file *file, struct pipe_inode_info *info, struct pipe_buffer *buf) | |
115 | { | |
116 | return kmap(buf->page); | |
117 | } | |
118 | ||
119 | static void anon_pipe_buf_unmap(struct pipe_inode_info *info, struct pipe_buffer *buf) | |
120 | { | |
121 | kunmap(buf->page); | |
122 | } | |
123 | ||
5abc97aa JA |
124 | static int anon_pipe_buf_steal(struct pipe_inode_info *info, |
125 | struct pipe_buffer *buf) | |
126 | { | |
5abc97aa JA |
127 | return 0; |
128 | } | |
129 | ||
1da177e4 LT |
130 | static struct pipe_buf_operations anon_pipe_buf_ops = { |
131 | .can_merge = 1, | |
132 | .map = anon_pipe_buf_map, | |
133 | .unmap = anon_pipe_buf_unmap, | |
134 | .release = anon_pipe_buf_release, | |
5abc97aa | 135 | .steal = anon_pipe_buf_steal, |
1da177e4 LT |
136 | }; |
137 | ||
138 | static ssize_t | |
139 | pipe_readv(struct file *filp, const struct iovec *_iov, | |
140 | unsigned long nr_segs, loff_t *ppos) | |
141 | { | |
142 | struct inode *inode = filp->f_dentry->d_inode; | |
143 | struct pipe_inode_info *info; | |
144 | int do_wakeup; | |
145 | ssize_t ret; | |
146 | struct iovec *iov = (struct iovec *)_iov; | |
147 | size_t total_len; | |
148 | ||
149 | total_len = iov_length(iov, nr_segs); | |
150 | /* Null read succeeds. */ | |
151 | if (unlikely(total_len == 0)) | |
152 | return 0; | |
153 | ||
154 | do_wakeup = 0; | |
155 | ret = 0; | |
1b1dcc1b | 156 | mutex_lock(PIPE_MUTEX(*inode)); |
1da177e4 LT |
157 | info = inode->i_pipe; |
158 | for (;;) { | |
159 | int bufs = info->nrbufs; | |
160 | if (bufs) { | |
161 | int curbuf = info->curbuf; | |
162 | struct pipe_buffer *buf = info->bufs + curbuf; | |
163 | struct pipe_buf_operations *ops = buf->ops; | |
164 | void *addr; | |
165 | size_t chars = buf->len; | |
166 | int error; | |
167 | ||
168 | if (chars > total_len) | |
169 | chars = total_len; | |
170 | ||
171 | addr = ops->map(filp, info, buf); | |
5274f052 JA |
172 | if (IS_ERR(addr)) { |
173 | if (!ret) | |
174 | ret = PTR_ERR(addr); | |
175 | break; | |
176 | } | |
1da177e4 LT |
177 | error = pipe_iov_copy_to_user(iov, addr + buf->offset, chars); |
178 | ops->unmap(info, buf); | |
179 | if (unlikely(error)) { | |
180 | if (!ret) ret = -EFAULT; | |
181 | break; | |
182 | } | |
183 | ret += chars; | |
184 | buf->offset += chars; | |
185 | buf->len -= chars; | |
186 | if (!buf->len) { | |
187 | buf->ops = NULL; | |
188 | ops->release(info, buf); | |
189 | curbuf = (curbuf + 1) & (PIPE_BUFFERS-1); | |
190 | info->curbuf = curbuf; | |
191 | info->nrbufs = --bufs; | |
192 | do_wakeup = 1; | |
193 | } | |
194 | total_len -= chars; | |
195 | if (!total_len) | |
196 | break; /* common path: read succeeded */ | |
197 | } | |
198 | if (bufs) /* More to do? */ | |
199 | continue; | |
200 | if (!PIPE_WRITERS(*inode)) | |
201 | break; | |
202 | if (!PIPE_WAITING_WRITERS(*inode)) { | |
203 | /* syscall merging: Usually we must not sleep | |
204 | * if O_NONBLOCK is set, or if we got some data. | |
205 | * But if a writer sleeps in kernel space, then | |
206 | * we can wait for that data without violating POSIX. | |
207 | */ | |
208 | if (ret) | |
209 | break; | |
210 | if (filp->f_flags & O_NONBLOCK) { | |
211 | ret = -EAGAIN; | |
212 | break; | |
213 | } | |
214 | } | |
215 | if (signal_pending(current)) { | |
216 | if (!ret) ret = -ERESTARTSYS; | |
217 | break; | |
218 | } | |
219 | if (do_wakeup) { | |
220 | wake_up_interruptible_sync(PIPE_WAIT(*inode)); | |
221 | kill_fasync(PIPE_FASYNC_WRITERS(*inode), SIGIO, POLL_OUT); | |
222 | } | |
223 | pipe_wait(inode); | |
224 | } | |
1b1dcc1b | 225 | mutex_unlock(PIPE_MUTEX(*inode)); |
1da177e4 LT |
226 | /* Signal writers asynchronously that there is more room. */ |
227 | if (do_wakeup) { | |
228 | wake_up_interruptible(PIPE_WAIT(*inode)); | |
229 | kill_fasync(PIPE_FASYNC_WRITERS(*inode), SIGIO, POLL_OUT); | |
230 | } | |
231 | if (ret > 0) | |
232 | file_accessed(filp); | |
233 | return ret; | |
234 | } | |
235 | ||
236 | static ssize_t | |
237 | pipe_read(struct file *filp, char __user *buf, size_t count, loff_t *ppos) | |
238 | { | |
239 | struct iovec iov = { .iov_base = buf, .iov_len = count }; | |
240 | return pipe_readv(filp, &iov, 1, ppos); | |
241 | } | |
242 | ||
243 | static ssize_t | |
244 | pipe_writev(struct file *filp, const struct iovec *_iov, | |
245 | unsigned long nr_segs, loff_t *ppos) | |
246 | { | |
247 | struct inode *inode = filp->f_dentry->d_inode; | |
248 | struct pipe_inode_info *info; | |
249 | ssize_t ret; | |
250 | int do_wakeup; | |
251 | struct iovec *iov = (struct iovec *)_iov; | |
252 | size_t total_len; | |
253 | ssize_t chars; | |
254 | ||
255 | total_len = iov_length(iov, nr_segs); | |
256 | /* Null write succeeds. */ | |
257 | if (unlikely(total_len == 0)) | |
258 | return 0; | |
259 | ||
260 | do_wakeup = 0; | |
261 | ret = 0; | |
1b1dcc1b | 262 | mutex_lock(PIPE_MUTEX(*inode)); |
1da177e4 LT |
263 | info = inode->i_pipe; |
264 | ||
265 | if (!PIPE_READERS(*inode)) { | |
266 | send_sig(SIGPIPE, current, 0); | |
267 | ret = -EPIPE; | |
268 | goto out; | |
269 | } | |
270 | ||
271 | /* We try to merge small writes */ | |
272 | chars = total_len & (PAGE_SIZE-1); /* size of the last buffer */ | |
273 | if (info->nrbufs && chars != 0) { | |
274 | int lastbuf = (info->curbuf + info->nrbufs - 1) & (PIPE_BUFFERS-1); | |
275 | struct pipe_buffer *buf = info->bufs + lastbuf; | |
276 | struct pipe_buf_operations *ops = buf->ops; | |
277 | int offset = buf->offset + buf->len; | |
278 | if (ops->can_merge && offset + chars <= PAGE_SIZE) { | |
5274f052 JA |
279 | void *addr; |
280 | int error; | |
281 | ||
282 | addr = ops->map(filp, info, buf); | |
283 | if (IS_ERR(addr)) { | |
284 | error = PTR_ERR(addr); | |
285 | goto out; | |
286 | } | |
287 | error = pipe_iov_copy_from_user(offset + addr, iov, | |
288 | chars); | |
1da177e4 LT |
289 | ops->unmap(info, buf); |
290 | ret = error; | |
291 | do_wakeup = 1; | |
292 | if (error) | |
293 | goto out; | |
294 | buf->len += chars; | |
295 | total_len -= chars; | |
296 | ret = chars; | |
297 | if (!total_len) | |
298 | goto out; | |
299 | } | |
300 | } | |
301 | ||
302 | for (;;) { | |
303 | int bufs; | |
304 | if (!PIPE_READERS(*inode)) { | |
305 | send_sig(SIGPIPE, current, 0); | |
306 | if (!ret) ret = -EPIPE; | |
307 | break; | |
308 | } | |
309 | bufs = info->nrbufs; | |
310 | if (bufs < PIPE_BUFFERS) { | |
311 | int newbuf = (info->curbuf + bufs) & (PIPE_BUFFERS-1); | |
312 | struct pipe_buffer *buf = info->bufs + newbuf; | |
313 | struct page *page = info->tmp_page; | |
314 | int error; | |
315 | ||
316 | if (!page) { | |
317 | page = alloc_page(GFP_HIGHUSER); | |
318 | if (unlikely(!page)) { | |
319 | ret = ret ? : -ENOMEM; | |
320 | break; | |
321 | } | |
322 | info->tmp_page = page; | |
323 | } | |
324 | /* Always wakeup, even if the copy fails. Otherwise | |
325 | * we lock up (O_NONBLOCK-)readers that sleep due to | |
326 | * syscall merging. | |
327 | * FIXME! Is this really true? | |
328 | */ | |
329 | do_wakeup = 1; | |
330 | chars = PAGE_SIZE; | |
331 | if (chars > total_len) | |
332 | chars = total_len; | |
333 | ||
334 | error = pipe_iov_copy_from_user(kmap(page), iov, chars); | |
335 | kunmap(page); | |
336 | if (unlikely(error)) { | |
337 | if (!ret) ret = -EFAULT; | |
338 | break; | |
339 | } | |
340 | ret += chars; | |
341 | ||
342 | /* Insert it into the buffer array */ | |
343 | buf->page = page; | |
344 | buf->ops = &anon_pipe_buf_ops; | |
345 | buf->offset = 0; | |
346 | buf->len = chars; | |
347 | info->nrbufs = ++bufs; | |
348 | info->tmp_page = NULL; | |
349 | ||
350 | total_len -= chars; | |
351 | if (!total_len) | |
352 | break; | |
353 | } | |
354 | if (bufs < PIPE_BUFFERS) | |
355 | continue; | |
356 | if (filp->f_flags & O_NONBLOCK) { | |
357 | if (!ret) ret = -EAGAIN; | |
358 | break; | |
359 | } | |
360 | if (signal_pending(current)) { | |
361 | if (!ret) ret = -ERESTARTSYS; | |
362 | break; | |
363 | } | |
364 | if (do_wakeup) { | |
365 | wake_up_interruptible_sync(PIPE_WAIT(*inode)); | |
366 | kill_fasync(PIPE_FASYNC_READERS(*inode), SIGIO, POLL_IN); | |
367 | do_wakeup = 0; | |
368 | } | |
369 | PIPE_WAITING_WRITERS(*inode)++; | |
370 | pipe_wait(inode); | |
371 | PIPE_WAITING_WRITERS(*inode)--; | |
372 | } | |
373 | out: | |
1b1dcc1b | 374 | mutex_unlock(PIPE_MUTEX(*inode)); |
1da177e4 LT |
375 | if (do_wakeup) { |
376 | wake_up_interruptible(PIPE_WAIT(*inode)); | |
377 | kill_fasync(PIPE_FASYNC_READERS(*inode), SIGIO, POLL_IN); | |
378 | } | |
379 | if (ret > 0) | |
870f4817 | 380 | file_update_time(filp); |
1da177e4 LT |
381 | return ret; |
382 | } | |
383 | ||
384 | static ssize_t | |
385 | pipe_write(struct file *filp, const char __user *buf, | |
386 | size_t count, loff_t *ppos) | |
387 | { | |
388 | struct iovec iov = { .iov_base = (void __user *)buf, .iov_len = count }; | |
389 | return pipe_writev(filp, &iov, 1, ppos); | |
390 | } | |
391 | ||
392 | static ssize_t | |
393 | bad_pipe_r(struct file *filp, char __user *buf, size_t count, loff_t *ppos) | |
394 | { | |
395 | return -EBADF; | |
396 | } | |
397 | ||
398 | static ssize_t | |
399 | bad_pipe_w(struct file *filp, const char __user *buf, size_t count, loff_t *ppos) | |
400 | { | |
401 | return -EBADF; | |
402 | } | |
403 | ||
404 | static int | |
405 | pipe_ioctl(struct inode *pino, struct file *filp, | |
406 | unsigned int cmd, unsigned long arg) | |
407 | { | |
408 | struct inode *inode = filp->f_dentry->d_inode; | |
409 | struct pipe_inode_info *info; | |
410 | int count, buf, nrbufs; | |
411 | ||
412 | switch (cmd) { | |
413 | case FIONREAD: | |
1b1dcc1b | 414 | mutex_lock(PIPE_MUTEX(*inode)); |
1da177e4 LT |
415 | info = inode->i_pipe; |
416 | count = 0; | |
417 | buf = info->curbuf; | |
418 | nrbufs = info->nrbufs; | |
419 | while (--nrbufs >= 0) { | |
420 | count += info->bufs[buf].len; | |
421 | buf = (buf+1) & (PIPE_BUFFERS-1); | |
422 | } | |
1b1dcc1b | 423 | mutex_unlock(PIPE_MUTEX(*inode)); |
1da177e4 LT |
424 | return put_user(count, (int __user *)arg); |
425 | default: | |
426 | return -EINVAL; | |
427 | } | |
428 | } | |
429 | ||
430 | /* No kernel lock held - fine */ | |
431 | static unsigned int | |
432 | pipe_poll(struct file *filp, poll_table *wait) | |
433 | { | |
434 | unsigned int mask; | |
435 | struct inode *inode = filp->f_dentry->d_inode; | |
436 | struct pipe_inode_info *info = inode->i_pipe; | |
437 | int nrbufs; | |
438 | ||
439 | poll_wait(filp, PIPE_WAIT(*inode), wait); | |
440 | ||
441 | /* Reading only -- no need for acquiring the semaphore. */ | |
442 | nrbufs = info->nrbufs; | |
443 | mask = 0; | |
444 | if (filp->f_mode & FMODE_READ) { | |
445 | mask = (nrbufs > 0) ? POLLIN | POLLRDNORM : 0; | |
446 | if (!PIPE_WRITERS(*inode) && filp->f_version != PIPE_WCOUNTER(*inode)) | |
447 | mask |= POLLHUP; | |
448 | } | |
449 | ||
450 | if (filp->f_mode & FMODE_WRITE) { | |
451 | mask |= (nrbufs < PIPE_BUFFERS) ? POLLOUT | POLLWRNORM : 0; | |
5e5d7a22 PE |
452 | /* |
453 | * Most Unices do not set POLLERR for FIFOs but on Linux they | |
454 | * behave exactly like pipes for poll(). | |
455 | */ | |
1da177e4 LT |
456 | if (!PIPE_READERS(*inode)) |
457 | mask |= POLLERR; | |
458 | } | |
459 | ||
460 | return mask; | |
461 | } | |
462 | ||
1da177e4 LT |
463 | static int |
464 | pipe_release(struct inode *inode, int decr, int decw) | |
465 | { | |
1b1dcc1b | 466 | mutex_lock(PIPE_MUTEX(*inode)); |
1da177e4 LT |
467 | PIPE_READERS(*inode) -= decr; |
468 | PIPE_WRITERS(*inode) -= decw; | |
469 | if (!PIPE_READERS(*inode) && !PIPE_WRITERS(*inode)) { | |
470 | free_pipe_info(inode); | |
471 | } else { | |
472 | wake_up_interruptible(PIPE_WAIT(*inode)); | |
473 | kill_fasync(PIPE_FASYNC_READERS(*inode), SIGIO, POLL_IN); | |
474 | kill_fasync(PIPE_FASYNC_WRITERS(*inode), SIGIO, POLL_OUT); | |
475 | } | |
1b1dcc1b | 476 | mutex_unlock(PIPE_MUTEX(*inode)); |
1da177e4 LT |
477 | |
478 | return 0; | |
479 | } | |
480 | ||
481 | static int | |
482 | pipe_read_fasync(int fd, struct file *filp, int on) | |
483 | { | |
484 | struct inode *inode = filp->f_dentry->d_inode; | |
485 | int retval; | |
486 | ||
1b1dcc1b | 487 | mutex_lock(PIPE_MUTEX(*inode)); |
1da177e4 | 488 | retval = fasync_helper(fd, filp, on, PIPE_FASYNC_READERS(*inode)); |
1b1dcc1b | 489 | mutex_unlock(PIPE_MUTEX(*inode)); |
1da177e4 LT |
490 | |
491 | if (retval < 0) | |
492 | return retval; | |
493 | ||
494 | return 0; | |
495 | } | |
496 | ||
497 | ||
498 | static int | |
499 | pipe_write_fasync(int fd, struct file *filp, int on) | |
500 | { | |
501 | struct inode *inode = filp->f_dentry->d_inode; | |
502 | int retval; | |
503 | ||
1b1dcc1b | 504 | mutex_lock(PIPE_MUTEX(*inode)); |
1da177e4 | 505 | retval = fasync_helper(fd, filp, on, PIPE_FASYNC_WRITERS(*inode)); |
1b1dcc1b | 506 | mutex_unlock(PIPE_MUTEX(*inode)); |
1da177e4 LT |
507 | |
508 | if (retval < 0) | |
509 | return retval; | |
510 | ||
511 | return 0; | |
512 | } | |
513 | ||
514 | ||
515 | static int | |
516 | pipe_rdwr_fasync(int fd, struct file *filp, int on) | |
517 | { | |
518 | struct inode *inode = filp->f_dentry->d_inode; | |
519 | int retval; | |
520 | ||
1b1dcc1b | 521 | mutex_lock(PIPE_MUTEX(*inode)); |
1da177e4 LT |
522 | |
523 | retval = fasync_helper(fd, filp, on, PIPE_FASYNC_READERS(*inode)); | |
524 | ||
525 | if (retval >= 0) | |
526 | retval = fasync_helper(fd, filp, on, PIPE_FASYNC_WRITERS(*inode)); | |
527 | ||
1b1dcc1b | 528 | mutex_unlock(PIPE_MUTEX(*inode)); |
1da177e4 LT |
529 | |
530 | if (retval < 0) | |
531 | return retval; | |
532 | ||
533 | return 0; | |
534 | } | |
535 | ||
536 | ||
537 | static int | |
538 | pipe_read_release(struct inode *inode, struct file *filp) | |
539 | { | |
540 | pipe_read_fasync(-1, filp, 0); | |
541 | return pipe_release(inode, 1, 0); | |
542 | } | |
543 | ||
544 | static int | |
545 | pipe_write_release(struct inode *inode, struct file *filp) | |
546 | { | |
547 | pipe_write_fasync(-1, filp, 0); | |
548 | return pipe_release(inode, 0, 1); | |
549 | } | |
550 | ||
551 | static int | |
552 | pipe_rdwr_release(struct inode *inode, struct file *filp) | |
553 | { | |
554 | int decr, decw; | |
555 | ||
556 | pipe_rdwr_fasync(-1, filp, 0); | |
557 | decr = (filp->f_mode & FMODE_READ) != 0; | |
558 | decw = (filp->f_mode & FMODE_WRITE) != 0; | |
559 | return pipe_release(inode, decr, decw); | |
560 | } | |
561 | ||
562 | static int | |
563 | pipe_read_open(struct inode *inode, struct file *filp) | |
564 | { | |
565 | /* We could have perhaps used atomic_t, but this and friends | |
566 | below are the only places. So it doesn't seem worthwhile. */ | |
1b1dcc1b | 567 | mutex_lock(PIPE_MUTEX(*inode)); |
1da177e4 | 568 | PIPE_READERS(*inode)++; |
1b1dcc1b | 569 | mutex_unlock(PIPE_MUTEX(*inode)); |
1da177e4 LT |
570 | |
571 | return 0; | |
572 | } | |
573 | ||
574 | static int | |
575 | pipe_write_open(struct inode *inode, struct file *filp) | |
576 | { | |
1b1dcc1b | 577 | mutex_lock(PIPE_MUTEX(*inode)); |
1da177e4 | 578 | PIPE_WRITERS(*inode)++; |
1b1dcc1b | 579 | mutex_unlock(PIPE_MUTEX(*inode)); |
1da177e4 LT |
580 | |
581 | return 0; | |
582 | } | |
583 | ||
584 | static int | |
585 | pipe_rdwr_open(struct inode *inode, struct file *filp) | |
586 | { | |
1b1dcc1b | 587 | mutex_lock(PIPE_MUTEX(*inode)); |
1da177e4 LT |
588 | if (filp->f_mode & FMODE_READ) |
589 | PIPE_READERS(*inode)++; | |
590 | if (filp->f_mode & FMODE_WRITE) | |
591 | PIPE_WRITERS(*inode)++; | |
1b1dcc1b | 592 | mutex_unlock(PIPE_MUTEX(*inode)); |
1da177e4 LT |
593 | |
594 | return 0; | |
595 | } | |
596 | ||
597 | /* | |
598 | * The file_operations structs are not static because they | |
599 | * are also used in linux/fs/fifo.c to do operations on FIFOs. | |
600 | */ | |
4b6f5d20 | 601 | const struct file_operations read_fifo_fops = { |
1da177e4 LT |
602 | .llseek = no_llseek, |
603 | .read = pipe_read, | |
604 | .readv = pipe_readv, | |
605 | .write = bad_pipe_w, | |
5e5d7a22 | 606 | .poll = pipe_poll, |
1da177e4 LT |
607 | .ioctl = pipe_ioctl, |
608 | .open = pipe_read_open, | |
609 | .release = pipe_read_release, | |
610 | .fasync = pipe_read_fasync, | |
611 | }; | |
612 | ||
4b6f5d20 | 613 | const struct file_operations write_fifo_fops = { |
1da177e4 LT |
614 | .llseek = no_llseek, |
615 | .read = bad_pipe_r, | |
616 | .write = pipe_write, | |
617 | .writev = pipe_writev, | |
5e5d7a22 | 618 | .poll = pipe_poll, |
1da177e4 LT |
619 | .ioctl = pipe_ioctl, |
620 | .open = pipe_write_open, | |
621 | .release = pipe_write_release, | |
622 | .fasync = pipe_write_fasync, | |
623 | }; | |
624 | ||
4b6f5d20 | 625 | const struct file_operations rdwr_fifo_fops = { |
1da177e4 LT |
626 | .llseek = no_llseek, |
627 | .read = pipe_read, | |
628 | .readv = pipe_readv, | |
629 | .write = pipe_write, | |
630 | .writev = pipe_writev, | |
5e5d7a22 | 631 | .poll = pipe_poll, |
1da177e4 LT |
632 | .ioctl = pipe_ioctl, |
633 | .open = pipe_rdwr_open, | |
634 | .release = pipe_rdwr_release, | |
635 | .fasync = pipe_rdwr_fasync, | |
636 | }; | |
637 | ||
a19cbd4b | 638 | static struct file_operations read_pipe_fops = { |
1da177e4 LT |
639 | .llseek = no_llseek, |
640 | .read = pipe_read, | |
641 | .readv = pipe_readv, | |
642 | .write = bad_pipe_w, | |
643 | .poll = pipe_poll, | |
644 | .ioctl = pipe_ioctl, | |
645 | .open = pipe_read_open, | |
646 | .release = pipe_read_release, | |
647 | .fasync = pipe_read_fasync, | |
648 | }; | |
649 | ||
a19cbd4b | 650 | static struct file_operations write_pipe_fops = { |
1da177e4 LT |
651 | .llseek = no_llseek, |
652 | .read = bad_pipe_r, | |
653 | .write = pipe_write, | |
654 | .writev = pipe_writev, | |
655 | .poll = pipe_poll, | |
656 | .ioctl = pipe_ioctl, | |
657 | .open = pipe_write_open, | |
658 | .release = pipe_write_release, | |
659 | .fasync = pipe_write_fasync, | |
660 | }; | |
661 | ||
a19cbd4b | 662 | static struct file_operations rdwr_pipe_fops = { |
1da177e4 LT |
663 | .llseek = no_llseek, |
664 | .read = pipe_read, | |
665 | .readv = pipe_readv, | |
666 | .write = pipe_write, | |
667 | .writev = pipe_writev, | |
668 | .poll = pipe_poll, | |
669 | .ioctl = pipe_ioctl, | |
670 | .open = pipe_rdwr_open, | |
671 | .release = pipe_rdwr_release, | |
672 | .fasync = pipe_rdwr_fasync, | |
673 | }; | |
674 | ||
675 | void free_pipe_info(struct inode *inode) | |
676 | { | |
677 | int i; | |
678 | struct pipe_inode_info *info = inode->i_pipe; | |
679 | ||
680 | inode->i_pipe = NULL; | |
681 | for (i = 0; i < PIPE_BUFFERS; i++) { | |
682 | struct pipe_buffer *buf = info->bufs + i; | |
683 | if (buf->ops) | |
684 | buf->ops->release(info, buf); | |
685 | } | |
686 | if (info->tmp_page) | |
687 | __free_page(info->tmp_page); | |
688 | kfree(info); | |
689 | } | |
690 | ||
691 | struct inode* pipe_new(struct inode* inode) | |
692 | { | |
693 | struct pipe_inode_info *info; | |
694 | ||
11b0b5ab | 695 | info = kzalloc(sizeof(struct pipe_inode_info), GFP_KERNEL); |
1da177e4 LT |
696 | if (!info) |
697 | goto fail_page; | |
1da177e4 LT |
698 | inode->i_pipe = info; |
699 | ||
700 | init_waitqueue_head(PIPE_WAIT(*inode)); | |
701 | PIPE_RCOUNTER(*inode) = PIPE_WCOUNTER(*inode) = 1; | |
702 | ||
703 | return inode; | |
704 | fail_page: | |
705 | return NULL; | |
706 | } | |
707 | ||
fa3536cc | 708 | static struct vfsmount *pipe_mnt __read_mostly; |
1da177e4 LT |
709 | static int pipefs_delete_dentry(struct dentry *dentry) |
710 | { | |
711 | return 1; | |
712 | } | |
713 | static struct dentry_operations pipefs_dentry_operations = { | |
714 | .d_delete = pipefs_delete_dentry, | |
715 | }; | |
716 | ||
717 | static struct inode * get_pipe_inode(void) | |
718 | { | |
719 | struct inode *inode = new_inode(pipe_mnt->mnt_sb); | |
720 | ||
721 | if (!inode) | |
722 | goto fail_inode; | |
723 | ||
724 | if(!pipe_new(inode)) | |
725 | goto fail_iput; | |
726 | PIPE_READERS(*inode) = PIPE_WRITERS(*inode) = 1; | |
727 | inode->i_fop = &rdwr_pipe_fops; | |
728 | ||
729 | /* | |
730 | * Mark the inode dirty from the very beginning, | |
731 | * that way it will never be moved to the dirty | |
732 | * list because "mark_inode_dirty()" will think | |
733 | * that it already _is_ on the dirty list. | |
734 | */ | |
735 | inode->i_state = I_DIRTY; | |
736 | inode->i_mode = S_IFIFO | S_IRUSR | S_IWUSR; | |
737 | inode->i_uid = current->fsuid; | |
738 | inode->i_gid = current->fsgid; | |
739 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; | |
740 | inode->i_blksize = PAGE_SIZE; | |
741 | return inode; | |
742 | ||
743 | fail_iput: | |
744 | iput(inode); | |
745 | fail_inode: | |
746 | return NULL; | |
747 | } | |
748 | ||
749 | int do_pipe(int *fd) | |
750 | { | |
751 | struct qstr this; | |
752 | char name[32]; | |
753 | struct dentry *dentry; | |
754 | struct inode * inode; | |
755 | struct file *f1, *f2; | |
756 | int error; | |
757 | int i,j; | |
758 | ||
759 | error = -ENFILE; | |
760 | f1 = get_empty_filp(); | |
761 | if (!f1) | |
762 | goto no_files; | |
763 | ||
764 | f2 = get_empty_filp(); | |
765 | if (!f2) | |
766 | goto close_f1; | |
767 | ||
768 | inode = get_pipe_inode(); | |
769 | if (!inode) | |
770 | goto close_f12; | |
771 | ||
772 | error = get_unused_fd(); | |
773 | if (error < 0) | |
774 | goto close_f12_inode; | |
775 | i = error; | |
776 | ||
777 | error = get_unused_fd(); | |
778 | if (error < 0) | |
779 | goto close_f12_inode_i; | |
780 | j = error; | |
781 | ||
782 | error = -ENOMEM; | |
783 | sprintf(name, "[%lu]", inode->i_ino); | |
784 | this.name = name; | |
785 | this.len = strlen(name); | |
786 | this.hash = inode->i_ino; /* will go */ | |
787 | dentry = d_alloc(pipe_mnt->mnt_sb->s_root, &this); | |
788 | if (!dentry) | |
789 | goto close_f12_inode_i_j; | |
790 | dentry->d_op = &pipefs_dentry_operations; | |
791 | d_add(dentry, inode); | |
792 | f1->f_vfsmnt = f2->f_vfsmnt = mntget(mntget(pipe_mnt)); | |
793 | f1->f_dentry = f2->f_dentry = dget(dentry); | |
794 | f1->f_mapping = f2->f_mapping = inode->i_mapping; | |
795 | ||
796 | /* read file */ | |
797 | f1->f_pos = f2->f_pos = 0; | |
798 | f1->f_flags = O_RDONLY; | |
799 | f1->f_op = &read_pipe_fops; | |
800 | f1->f_mode = FMODE_READ; | |
801 | f1->f_version = 0; | |
802 | ||
803 | /* write file */ | |
804 | f2->f_flags = O_WRONLY; | |
805 | f2->f_op = &write_pipe_fops; | |
806 | f2->f_mode = FMODE_WRITE; | |
807 | f2->f_version = 0; | |
808 | ||
809 | fd_install(i, f1); | |
810 | fd_install(j, f2); | |
811 | fd[0] = i; | |
812 | fd[1] = j; | |
813 | return 0; | |
814 | ||
815 | close_f12_inode_i_j: | |
816 | put_unused_fd(j); | |
817 | close_f12_inode_i: | |
818 | put_unused_fd(i); | |
819 | close_f12_inode: | |
820 | free_pipe_info(inode); | |
821 | iput(inode); | |
822 | close_f12: | |
823 | put_filp(f2); | |
824 | close_f1: | |
825 | put_filp(f1); | |
826 | no_files: | |
827 | return error; | |
828 | } | |
829 | ||
830 | /* | |
831 | * pipefs should _never_ be mounted by userland - too much of security hassle, | |
832 | * no real gain from having the whole whorehouse mounted. So we don't need | |
833 | * any operations on the root directory. However, we need a non-trivial | |
834 | * d_name - pipe: will go nicely and kill the special-casing in procfs. | |
835 | */ | |
836 | ||
837 | static struct super_block *pipefs_get_sb(struct file_system_type *fs_type, | |
838 | int flags, const char *dev_name, void *data) | |
839 | { | |
840 | return get_sb_pseudo(fs_type, "pipe:", NULL, PIPEFS_MAGIC); | |
841 | } | |
842 | ||
843 | static struct file_system_type pipe_fs_type = { | |
844 | .name = "pipefs", | |
845 | .get_sb = pipefs_get_sb, | |
846 | .kill_sb = kill_anon_super, | |
847 | }; | |
848 | ||
849 | static int __init init_pipe_fs(void) | |
850 | { | |
851 | int err = register_filesystem(&pipe_fs_type); | |
852 | if (!err) { | |
853 | pipe_mnt = kern_mount(&pipe_fs_type); | |
854 | if (IS_ERR(pipe_mnt)) { | |
855 | err = PTR_ERR(pipe_mnt); | |
856 | unregister_filesystem(&pipe_fs_type); | |
857 | } | |
858 | } | |
859 | return err; | |
860 | } | |
861 | ||
862 | static void __exit exit_pipe_fs(void) | |
863 | { | |
864 | unregister_filesystem(&pipe_fs_type); | |
865 | mntput(pipe_mnt); | |
866 | } | |
867 | ||
868 | fs_initcall(init_pipe_fs); | |
869 | module_exit(exit_pipe_fs); |