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 | ||
3e7ee3e7 JA |
98 | buf->flags &= ~PIPE_BUF_FLAG_STOLEN; |
99 | ||
5274f052 JA |
100 | /* |
101 | * If nobody else uses this page, and we don't already have a | |
102 | * temporary page, let's keep track of it as a one-deep | |
103 | * allocation cache | |
104 | */ | |
105 | if (page_count(page) == 1 && !info->tmp_page) { | |
106 | info->tmp_page = page; | |
1da177e4 LT |
107 | return; |
108 | } | |
5274f052 JA |
109 | |
110 | /* | |
111 | * Otherwise just release our reference to it | |
112 | */ | |
113 | page_cache_release(page); | |
1da177e4 LT |
114 | } |
115 | ||
116 | static void *anon_pipe_buf_map(struct file *file, struct pipe_inode_info *info, struct pipe_buffer *buf) | |
117 | { | |
118 | return kmap(buf->page); | |
119 | } | |
120 | ||
121 | static void anon_pipe_buf_unmap(struct pipe_inode_info *info, struct pipe_buffer *buf) | |
122 | { | |
123 | kunmap(buf->page); | |
124 | } | |
125 | ||
5abc97aa JA |
126 | static int anon_pipe_buf_steal(struct pipe_inode_info *info, |
127 | struct pipe_buffer *buf) | |
128 | { | |
3e7ee3e7 | 129 | buf->flags |= PIPE_BUF_FLAG_STOLEN; |
5abc97aa JA |
130 | return 0; |
131 | } | |
132 | ||
1da177e4 LT |
133 | static struct pipe_buf_operations anon_pipe_buf_ops = { |
134 | .can_merge = 1, | |
135 | .map = anon_pipe_buf_map, | |
136 | .unmap = anon_pipe_buf_unmap, | |
137 | .release = anon_pipe_buf_release, | |
5abc97aa | 138 | .steal = anon_pipe_buf_steal, |
1da177e4 LT |
139 | }; |
140 | ||
141 | static ssize_t | |
142 | pipe_readv(struct file *filp, const struct iovec *_iov, | |
143 | unsigned long nr_segs, loff_t *ppos) | |
144 | { | |
145 | struct inode *inode = filp->f_dentry->d_inode; | |
146 | struct pipe_inode_info *info; | |
147 | int do_wakeup; | |
148 | ssize_t ret; | |
149 | struct iovec *iov = (struct iovec *)_iov; | |
150 | size_t total_len; | |
151 | ||
152 | total_len = iov_length(iov, nr_segs); | |
153 | /* Null read succeeds. */ | |
154 | if (unlikely(total_len == 0)) | |
155 | return 0; | |
156 | ||
157 | do_wakeup = 0; | |
158 | ret = 0; | |
1b1dcc1b | 159 | mutex_lock(PIPE_MUTEX(*inode)); |
1da177e4 LT |
160 | info = inode->i_pipe; |
161 | for (;;) { | |
162 | int bufs = info->nrbufs; | |
163 | if (bufs) { | |
164 | int curbuf = info->curbuf; | |
165 | struct pipe_buffer *buf = info->bufs + curbuf; | |
166 | struct pipe_buf_operations *ops = buf->ops; | |
167 | void *addr; | |
168 | size_t chars = buf->len; | |
169 | int error; | |
170 | ||
171 | if (chars > total_len) | |
172 | chars = total_len; | |
173 | ||
174 | addr = ops->map(filp, info, buf); | |
5274f052 JA |
175 | if (IS_ERR(addr)) { |
176 | if (!ret) | |
177 | ret = PTR_ERR(addr); | |
178 | break; | |
179 | } | |
1da177e4 LT |
180 | error = pipe_iov_copy_to_user(iov, addr + buf->offset, chars); |
181 | ops->unmap(info, buf); | |
182 | if (unlikely(error)) { | |
183 | if (!ret) ret = -EFAULT; | |
184 | break; | |
185 | } | |
186 | ret += chars; | |
187 | buf->offset += chars; | |
188 | buf->len -= chars; | |
189 | if (!buf->len) { | |
190 | buf->ops = NULL; | |
191 | ops->release(info, buf); | |
192 | curbuf = (curbuf + 1) & (PIPE_BUFFERS-1); | |
193 | info->curbuf = curbuf; | |
194 | info->nrbufs = --bufs; | |
195 | do_wakeup = 1; | |
196 | } | |
197 | total_len -= chars; | |
198 | if (!total_len) | |
199 | break; /* common path: read succeeded */ | |
200 | } | |
201 | if (bufs) /* More to do? */ | |
202 | continue; | |
203 | if (!PIPE_WRITERS(*inode)) | |
204 | break; | |
205 | if (!PIPE_WAITING_WRITERS(*inode)) { | |
206 | /* syscall merging: Usually we must not sleep | |
207 | * if O_NONBLOCK is set, or if we got some data. | |
208 | * But if a writer sleeps in kernel space, then | |
209 | * we can wait for that data without violating POSIX. | |
210 | */ | |
211 | if (ret) | |
212 | break; | |
213 | if (filp->f_flags & O_NONBLOCK) { | |
214 | ret = -EAGAIN; | |
215 | break; | |
216 | } | |
217 | } | |
218 | if (signal_pending(current)) { | |
219 | if (!ret) ret = -ERESTARTSYS; | |
220 | break; | |
221 | } | |
222 | if (do_wakeup) { | |
223 | wake_up_interruptible_sync(PIPE_WAIT(*inode)); | |
224 | kill_fasync(PIPE_FASYNC_WRITERS(*inode), SIGIO, POLL_OUT); | |
225 | } | |
226 | pipe_wait(inode); | |
227 | } | |
1b1dcc1b | 228 | mutex_unlock(PIPE_MUTEX(*inode)); |
1da177e4 LT |
229 | /* Signal writers asynchronously that there is more room. */ |
230 | if (do_wakeup) { | |
231 | wake_up_interruptible(PIPE_WAIT(*inode)); | |
232 | kill_fasync(PIPE_FASYNC_WRITERS(*inode), SIGIO, POLL_OUT); | |
233 | } | |
234 | if (ret > 0) | |
235 | file_accessed(filp); | |
236 | return ret; | |
237 | } | |
238 | ||
239 | static ssize_t | |
240 | pipe_read(struct file *filp, char __user *buf, size_t count, loff_t *ppos) | |
241 | { | |
242 | struct iovec iov = { .iov_base = buf, .iov_len = count }; | |
243 | return pipe_readv(filp, &iov, 1, ppos); | |
244 | } | |
245 | ||
246 | static ssize_t | |
247 | pipe_writev(struct file *filp, const struct iovec *_iov, | |
248 | unsigned long nr_segs, loff_t *ppos) | |
249 | { | |
250 | struct inode *inode = filp->f_dentry->d_inode; | |
251 | struct pipe_inode_info *info; | |
252 | ssize_t ret; | |
253 | int do_wakeup; | |
254 | struct iovec *iov = (struct iovec *)_iov; | |
255 | size_t total_len; | |
256 | ssize_t chars; | |
257 | ||
258 | total_len = iov_length(iov, nr_segs); | |
259 | /* Null write succeeds. */ | |
260 | if (unlikely(total_len == 0)) | |
261 | return 0; | |
262 | ||
263 | do_wakeup = 0; | |
264 | ret = 0; | |
1b1dcc1b | 265 | mutex_lock(PIPE_MUTEX(*inode)); |
1da177e4 LT |
266 | info = inode->i_pipe; |
267 | ||
268 | if (!PIPE_READERS(*inode)) { | |
269 | send_sig(SIGPIPE, current, 0); | |
270 | ret = -EPIPE; | |
271 | goto out; | |
272 | } | |
273 | ||
274 | /* We try to merge small writes */ | |
275 | chars = total_len & (PAGE_SIZE-1); /* size of the last buffer */ | |
276 | if (info->nrbufs && chars != 0) { | |
277 | int lastbuf = (info->curbuf + info->nrbufs - 1) & (PIPE_BUFFERS-1); | |
278 | struct pipe_buffer *buf = info->bufs + lastbuf; | |
279 | struct pipe_buf_operations *ops = buf->ops; | |
280 | int offset = buf->offset + buf->len; | |
281 | if (ops->can_merge && offset + chars <= PAGE_SIZE) { | |
5274f052 JA |
282 | void *addr; |
283 | int error; | |
284 | ||
285 | addr = ops->map(filp, info, buf); | |
286 | if (IS_ERR(addr)) { | |
287 | error = PTR_ERR(addr); | |
288 | goto out; | |
289 | } | |
290 | error = pipe_iov_copy_from_user(offset + addr, iov, | |
291 | chars); | |
1da177e4 LT |
292 | ops->unmap(info, buf); |
293 | ret = error; | |
294 | do_wakeup = 1; | |
295 | if (error) | |
296 | goto out; | |
297 | buf->len += chars; | |
298 | total_len -= chars; | |
299 | ret = chars; | |
300 | if (!total_len) | |
301 | goto out; | |
302 | } | |
303 | } | |
304 | ||
305 | for (;;) { | |
306 | int bufs; | |
307 | if (!PIPE_READERS(*inode)) { | |
308 | send_sig(SIGPIPE, current, 0); | |
309 | if (!ret) ret = -EPIPE; | |
310 | break; | |
311 | } | |
312 | bufs = info->nrbufs; | |
313 | if (bufs < PIPE_BUFFERS) { | |
314 | int newbuf = (info->curbuf + bufs) & (PIPE_BUFFERS-1); | |
315 | struct pipe_buffer *buf = info->bufs + newbuf; | |
316 | struct page *page = info->tmp_page; | |
317 | int error; | |
318 | ||
319 | if (!page) { | |
320 | page = alloc_page(GFP_HIGHUSER); | |
321 | if (unlikely(!page)) { | |
322 | ret = ret ? : -ENOMEM; | |
323 | break; | |
324 | } | |
325 | info->tmp_page = page; | |
326 | } | |
327 | /* Always wakeup, even if the copy fails. Otherwise | |
328 | * we lock up (O_NONBLOCK-)readers that sleep due to | |
329 | * syscall merging. | |
330 | * FIXME! Is this really true? | |
331 | */ | |
332 | do_wakeup = 1; | |
333 | chars = PAGE_SIZE; | |
334 | if (chars > total_len) | |
335 | chars = total_len; | |
336 | ||
337 | error = pipe_iov_copy_from_user(kmap(page), iov, chars); | |
338 | kunmap(page); | |
339 | if (unlikely(error)) { | |
340 | if (!ret) ret = -EFAULT; | |
341 | break; | |
342 | } | |
343 | ret += chars; | |
344 | ||
345 | /* Insert it into the buffer array */ | |
346 | buf->page = page; | |
347 | buf->ops = &anon_pipe_buf_ops; | |
348 | buf->offset = 0; | |
349 | buf->len = chars; | |
350 | info->nrbufs = ++bufs; | |
351 | info->tmp_page = NULL; | |
352 | ||
353 | total_len -= chars; | |
354 | if (!total_len) | |
355 | break; | |
356 | } | |
357 | if (bufs < PIPE_BUFFERS) | |
358 | continue; | |
359 | if (filp->f_flags & O_NONBLOCK) { | |
360 | if (!ret) ret = -EAGAIN; | |
361 | break; | |
362 | } | |
363 | if (signal_pending(current)) { | |
364 | if (!ret) ret = -ERESTARTSYS; | |
365 | break; | |
366 | } | |
367 | if (do_wakeup) { | |
368 | wake_up_interruptible_sync(PIPE_WAIT(*inode)); | |
369 | kill_fasync(PIPE_FASYNC_READERS(*inode), SIGIO, POLL_IN); | |
370 | do_wakeup = 0; | |
371 | } | |
372 | PIPE_WAITING_WRITERS(*inode)++; | |
373 | pipe_wait(inode); | |
374 | PIPE_WAITING_WRITERS(*inode)--; | |
375 | } | |
376 | out: | |
1b1dcc1b | 377 | mutex_unlock(PIPE_MUTEX(*inode)); |
1da177e4 LT |
378 | if (do_wakeup) { |
379 | wake_up_interruptible(PIPE_WAIT(*inode)); | |
380 | kill_fasync(PIPE_FASYNC_READERS(*inode), SIGIO, POLL_IN); | |
381 | } | |
382 | if (ret > 0) | |
870f4817 | 383 | file_update_time(filp); |
1da177e4 LT |
384 | return ret; |
385 | } | |
386 | ||
387 | static ssize_t | |
388 | pipe_write(struct file *filp, const char __user *buf, | |
389 | size_t count, loff_t *ppos) | |
390 | { | |
391 | struct iovec iov = { .iov_base = (void __user *)buf, .iov_len = count }; | |
392 | return pipe_writev(filp, &iov, 1, ppos); | |
393 | } | |
394 | ||
395 | static ssize_t | |
396 | bad_pipe_r(struct file *filp, char __user *buf, size_t count, loff_t *ppos) | |
397 | { | |
398 | return -EBADF; | |
399 | } | |
400 | ||
401 | static ssize_t | |
402 | bad_pipe_w(struct file *filp, const char __user *buf, size_t count, loff_t *ppos) | |
403 | { | |
404 | return -EBADF; | |
405 | } | |
406 | ||
407 | static int | |
408 | pipe_ioctl(struct inode *pino, struct file *filp, | |
409 | unsigned int cmd, unsigned long arg) | |
410 | { | |
411 | struct inode *inode = filp->f_dentry->d_inode; | |
412 | struct pipe_inode_info *info; | |
413 | int count, buf, nrbufs; | |
414 | ||
415 | switch (cmd) { | |
416 | case FIONREAD: | |
1b1dcc1b | 417 | mutex_lock(PIPE_MUTEX(*inode)); |
1da177e4 LT |
418 | info = inode->i_pipe; |
419 | count = 0; | |
420 | buf = info->curbuf; | |
421 | nrbufs = info->nrbufs; | |
422 | while (--nrbufs >= 0) { | |
423 | count += info->bufs[buf].len; | |
424 | buf = (buf+1) & (PIPE_BUFFERS-1); | |
425 | } | |
1b1dcc1b | 426 | mutex_unlock(PIPE_MUTEX(*inode)); |
1da177e4 LT |
427 | return put_user(count, (int __user *)arg); |
428 | default: | |
429 | return -EINVAL; | |
430 | } | |
431 | } | |
432 | ||
433 | /* No kernel lock held - fine */ | |
434 | static unsigned int | |
435 | pipe_poll(struct file *filp, poll_table *wait) | |
436 | { | |
437 | unsigned int mask; | |
438 | struct inode *inode = filp->f_dentry->d_inode; | |
439 | struct pipe_inode_info *info = inode->i_pipe; | |
440 | int nrbufs; | |
441 | ||
442 | poll_wait(filp, PIPE_WAIT(*inode), wait); | |
443 | ||
444 | /* Reading only -- no need for acquiring the semaphore. */ | |
445 | nrbufs = info->nrbufs; | |
446 | mask = 0; | |
447 | if (filp->f_mode & FMODE_READ) { | |
448 | mask = (nrbufs > 0) ? POLLIN | POLLRDNORM : 0; | |
449 | if (!PIPE_WRITERS(*inode) && filp->f_version != PIPE_WCOUNTER(*inode)) | |
450 | mask |= POLLHUP; | |
451 | } | |
452 | ||
453 | if (filp->f_mode & FMODE_WRITE) { | |
454 | mask |= (nrbufs < PIPE_BUFFERS) ? POLLOUT | POLLWRNORM : 0; | |
5e5d7a22 PE |
455 | /* |
456 | * Most Unices do not set POLLERR for FIFOs but on Linux they | |
457 | * behave exactly like pipes for poll(). | |
458 | */ | |
1da177e4 LT |
459 | if (!PIPE_READERS(*inode)) |
460 | mask |= POLLERR; | |
461 | } | |
462 | ||
463 | return mask; | |
464 | } | |
465 | ||
1da177e4 LT |
466 | static int |
467 | pipe_release(struct inode *inode, int decr, int decw) | |
468 | { | |
1b1dcc1b | 469 | mutex_lock(PIPE_MUTEX(*inode)); |
1da177e4 LT |
470 | PIPE_READERS(*inode) -= decr; |
471 | PIPE_WRITERS(*inode) -= decw; | |
472 | if (!PIPE_READERS(*inode) && !PIPE_WRITERS(*inode)) { | |
473 | free_pipe_info(inode); | |
474 | } else { | |
475 | wake_up_interruptible(PIPE_WAIT(*inode)); | |
476 | kill_fasync(PIPE_FASYNC_READERS(*inode), SIGIO, POLL_IN); | |
477 | kill_fasync(PIPE_FASYNC_WRITERS(*inode), SIGIO, POLL_OUT); | |
478 | } | |
1b1dcc1b | 479 | mutex_unlock(PIPE_MUTEX(*inode)); |
1da177e4 LT |
480 | |
481 | return 0; | |
482 | } | |
483 | ||
484 | static int | |
485 | pipe_read_fasync(int fd, struct file *filp, int on) | |
486 | { | |
487 | struct inode *inode = filp->f_dentry->d_inode; | |
488 | int retval; | |
489 | ||
1b1dcc1b | 490 | mutex_lock(PIPE_MUTEX(*inode)); |
1da177e4 | 491 | retval = fasync_helper(fd, filp, on, PIPE_FASYNC_READERS(*inode)); |
1b1dcc1b | 492 | mutex_unlock(PIPE_MUTEX(*inode)); |
1da177e4 LT |
493 | |
494 | if (retval < 0) | |
495 | return retval; | |
496 | ||
497 | return 0; | |
498 | } | |
499 | ||
500 | ||
501 | static int | |
502 | pipe_write_fasync(int fd, struct file *filp, int on) | |
503 | { | |
504 | struct inode *inode = filp->f_dentry->d_inode; | |
505 | int retval; | |
506 | ||
1b1dcc1b | 507 | mutex_lock(PIPE_MUTEX(*inode)); |
1da177e4 | 508 | retval = fasync_helper(fd, filp, on, PIPE_FASYNC_WRITERS(*inode)); |
1b1dcc1b | 509 | mutex_unlock(PIPE_MUTEX(*inode)); |
1da177e4 LT |
510 | |
511 | if (retval < 0) | |
512 | return retval; | |
513 | ||
514 | return 0; | |
515 | } | |
516 | ||
517 | ||
518 | static int | |
519 | pipe_rdwr_fasync(int fd, struct file *filp, int on) | |
520 | { | |
521 | struct inode *inode = filp->f_dentry->d_inode; | |
522 | int retval; | |
523 | ||
1b1dcc1b | 524 | mutex_lock(PIPE_MUTEX(*inode)); |
1da177e4 LT |
525 | |
526 | retval = fasync_helper(fd, filp, on, PIPE_FASYNC_READERS(*inode)); | |
527 | ||
528 | if (retval >= 0) | |
529 | retval = fasync_helper(fd, filp, on, PIPE_FASYNC_WRITERS(*inode)); | |
530 | ||
1b1dcc1b | 531 | mutex_unlock(PIPE_MUTEX(*inode)); |
1da177e4 LT |
532 | |
533 | if (retval < 0) | |
534 | return retval; | |
535 | ||
536 | return 0; | |
537 | } | |
538 | ||
539 | ||
540 | static int | |
541 | pipe_read_release(struct inode *inode, struct file *filp) | |
542 | { | |
543 | pipe_read_fasync(-1, filp, 0); | |
544 | return pipe_release(inode, 1, 0); | |
545 | } | |
546 | ||
547 | static int | |
548 | pipe_write_release(struct inode *inode, struct file *filp) | |
549 | { | |
550 | pipe_write_fasync(-1, filp, 0); | |
551 | return pipe_release(inode, 0, 1); | |
552 | } | |
553 | ||
554 | static int | |
555 | pipe_rdwr_release(struct inode *inode, struct file *filp) | |
556 | { | |
557 | int decr, decw; | |
558 | ||
559 | pipe_rdwr_fasync(-1, filp, 0); | |
560 | decr = (filp->f_mode & FMODE_READ) != 0; | |
561 | decw = (filp->f_mode & FMODE_WRITE) != 0; | |
562 | return pipe_release(inode, decr, decw); | |
563 | } | |
564 | ||
565 | static int | |
566 | pipe_read_open(struct inode *inode, struct file *filp) | |
567 | { | |
568 | /* We could have perhaps used atomic_t, but this and friends | |
569 | below are the only places. So it doesn't seem worthwhile. */ | |
1b1dcc1b | 570 | mutex_lock(PIPE_MUTEX(*inode)); |
1da177e4 | 571 | PIPE_READERS(*inode)++; |
1b1dcc1b | 572 | mutex_unlock(PIPE_MUTEX(*inode)); |
1da177e4 LT |
573 | |
574 | return 0; | |
575 | } | |
576 | ||
577 | static int | |
578 | pipe_write_open(struct inode *inode, struct file *filp) | |
579 | { | |
1b1dcc1b | 580 | mutex_lock(PIPE_MUTEX(*inode)); |
1da177e4 | 581 | PIPE_WRITERS(*inode)++; |
1b1dcc1b | 582 | mutex_unlock(PIPE_MUTEX(*inode)); |
1da177e4 LT |
583 | |
584 | return 0; | |
585 | } | |
586 | ||
587 | static int | |
588 | pipe_rdwr_open(struct inode *inode, struct file *filp) | |
589 | { | |
1b1dcc1b | 590 | mutex_lock(PIPE_MUTEX(*inode)); |
1da177e4 LT |
591 | if (filp->f_mode & FMODE_READ) |
592 | PIPE_READERS(*inode)++; | |
593 | if (filp->f_mode & FMODE_WRITE) | |
594 | PIPE_WRITERS(*inode)++; | |
1b1dcc1b | 595 | mutex_unlock(PIPE_MUTEX(*inode)); |
1da177e4 LT |
596 | |
597 | return 0; | |
598 | } | |
599 | ||
600 | /* | |
601 | * The file_operations structs are not static because they | |
602 | * are also used in linux/fs/fifo.c to do operations on FIFOs. | |
603 | */ | |
4b6f5d20 | 604 | const struct file_operations read_fifo_fops = { |
1da177e4 LT |
605 | .llseek = no_llseek, |
606 | .read = pipe_read, | |
607 | .readv = pipe_readv, | |
608 | .write = bad_pipe_w, | |
5e5d7a22 | 609 | .poll = pipe_poll, |
1da177e4 LT |
610 | .ioctl = pipe_ioctl, |
611 | .open = pipe_read_open, | |
612 | .release = pipe_read_release, | |
613 | .fasync = pipe_read_fasync, | |
614 | }; | |
615 | ||
4b6f5d20 | 616 | const struct file_operations write_fifo_fops = { |
1da177e4 LT |
617 | .llseek = no_llseek, |
618 | .read = bad_pipe_r, | |
619 | .write = pipe_write, | |
620 | .writev = pipe_writev, | |
5e5d7a22 | 621 | .poll = pipe_poll, |
1da177e4 LT |
622 | .ioctl = pipe_ioctl, |
623 | .open = pipe_write_open, | |
624 | .release = pipe_write_release, | |
625 | .fasync = pipe_write_fasync, | |
626 | }; | |
627 | ||
4b6f5d20 | 628 | const struct file_operations rdwr_fifo_fops = { |
1da177e4 LT |
629 | .llseek = no_llseek, |
630 | .read = pipe_read, | |
631 | .readv = pipe_readv, | |
632 | .write = pipe_write, | |
633 | .writev = pipe_writev, | |
5e5d7a22 | 634 | .poll = pipe_poll, |
1da177e4 LT |
635 | .ioctl = pipe_ioctl, |
636 | .open = pipe_rdwr_open, | |
637 | .release = pipe_rdwr_release, | |
638 | .fasync = pipe_rdwr_fasync, | |
639 | }; | |
640 | ||
a19cbd4b | 641 | static struct file_operations read_pipe_fops = { |
1da177e4 LT |
642 | .llseek = no_llseek, |
643 | .read = pipe_read, | |
644 | .readv = pipe_readv, | |
645 | .write = bad_pipe_w, | |
646 | .poll = pipe_poll, | |
647 | .ioctl = pipe_ioctl, | |
648 | .open = pipe_read_open, | |
649 | .release = pipe_read_release, | |
650 | .fasync = pipe_read_fasync, | |
651 | }; | |
652 | ||
a19cbd4b | 653 | static struct file_operations write_pipe_fops = { |
1da177e4 LT |
654 | .llseek = no_llseek, |
655 | .read = bad_pipe_r, | |
656 | .write = pipe_write, | |
657 | .writev = pipe_writev, | |
658 | .poll = pipe_poll, | |
659 | .ioctl = pipe_ioctl, | |
660 | .open = pipe_write_open, | |
661 | .release = pipe_write_release, | |
662 | .fasync = pipe_write_fasync, | |
663 | }; | |
664 | ||
a19cbd4b | 665 | static struct file_operations rdwr_pipe_fops = { |
1da177e4 LT |
666 | .llseek = no_llseek, |
667 | .read = pipe_read, | |
668 | .readv = pipe_readv, | |
669 | .write = pipe_write, | |
670 | .writev = pipe_writev, | |
671 | .poll = pipe_poll, | |
672 | .ioctl = pipe_ioctl, | |
673 | .open = pipe_rdwr_open, | |
674 | .release = pipe_rdwr_release, | |
675 | .fasync = pipe_rdwr_fasync, | |
676 | }; | |
677 | ||
678 | void free_pipe_info(struct inode *inode) | |
679 | { | |
680 | int i; | |
681 | struct pipe_inode_info *info = inode->i_pipe; | |
682 | ||
683 | inode->i_pipe = NULL; | |
684 | for (i = 0; i < PIPE_BUFFERS; i++) { | |
685 | struct pipe_buffer *buf = info->bufs + i; | |
686 | if (buf->ops) | |
687 | buf->ops->release(info, buf); | |
688 | } | |
689 | if (info->tmp_page) | |
690 | __free_page(info->tmp_page); | |
691 | kfree(info); | |
692 | } | |
693 | ||
694 | struct inode* pipe_new(struct inode* inode) | |
695 | { | |
696 | struct pipe_inode_info *info; | |
697 | ||
11b0b5ab | 698 | info = kzalloc(sizeof(struct pipe_inode_info), GFP_KERNEL); |
1da177e4 LT |
699 | if (!info) |
700 | goto fail_page; | |
1da177e4 LT |
701 | inode->i_pipe = info; |
702 | ||
703 | init_waitqueue_head(PIPE_WAIT(*inode)); | |
704 | PIPE_RCOUNTER(*inode) = PIPE_WCOUNTER(*inode) = 1; | |
705 | ||
706 | return inode; | |
707 | fail_page: | |
708 | return NULL; | |
709 | } | |
710 | ||
fa3536cc | 711 | static struct vfsmount *pipe_mnt __read_mostly; |
1da177e4 LT |
712 | static int pipefs_delete_dentry(struct dentry *dentry) |
713 | { | |
714 | return 1; | |
715 | } | |
716 | static struct dentry_operations pipefs_dentry_operations = { | |
717 | .d_delete = pipefs_delete_dentry, | |
718 | }; | |
719 | ||
720 | static struct inode * get_pipe_inode(void) | |
721 | { | |
722 | struct inode *inode = new_inode(pipe_mnt->mnt_sb); | |
723 | ||
724 | if (!inode) | |
725 | goto fail_inode; | |
726 | ||
727 | if(!pipe_new(inode)) | |
728 | goto fail_iput; | |
729 | PIPE_READERS(*inode) = PIPE_WRITERS(*inode) = 1; | |
730 | inode->i_fop = &rdwr_pipe_fops; | |
731 | ||
732 | /* | |
733 | * Mark the inode dirty from the very beginning, | |
734 | * that way it will never be moved to the dirty | |
735 | * list because "mark_inode_dirty()" will think | |
736 | * that it already _is_ on the dirty list. | |
737 | */ | |
738 | inode->i_state = I_DIRTY; | |
739 | inode->i_mode = S_IFIFO | S_IRUSR | S_IWUSR; | |
740 | inode->i_uid = current->fsuid; | |
741 | inode->i_gid = current->fsgid; | |
742 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; | |
743 | inode->i_blksize = PAGE_SIZE; | |
744 | return inode; | |
745 | ||
746 | fail_iput: | |
747 | iput(inode); | |
748 | fail_inode: | |
749 | return NULL; | |
750 | } | |
751 | ||
752 | int do_pipe(int *fd) | |
753 | { | |
754 | struct qstr this; | |
755 | char name[32]; | |
756 | struct dentry *dentry; | |
757 | struct inode * inode; | |
758 | struct file *f1, *f2; | |
759 | int error; | |
760 | int i,j; | |
761 | ||
762 | error = -ENFILE; | |
763 | f1 = get_empty_filp(); | |
764 | if (!f1) | |
765 | goto no_files; | |
766 | ||
767 | f2 = get_empty_filp(); | |
768 | if (!f2) | |
769 | goto close_f1; | |
770 | ||
771 | inode = get_pipe_inode(); | |
772 | if (!inode) | |
773 | goto close_f12; | |
774 | ||
775 | error = get_unused_fd(); | |
776 | if (error < 0) | |
777 | goto close_f12_inode; | |
778 | i = error; | |
779 | ||
780 | error = get_unused_fd(); | |
781 | if (error < 0) | |
782 | goto close_f12_inode_i; | |
783 | j = error; | |
784 | ||
785 | error = -ENOMEM; | |
786 | sprintf(name, "[%lu]", inode->i_ino); | |
787 | this.name = name; | |
788 | this.len = strlen(name); | |
789 | this.hash = inode->i_ino; /* will go */ | |
790 | dentry = d_alloc(pipe_mnt->mnt_sb->s_root, &this); | |
791 | if (!dentry) | |
792 | goto close_f12_inode_i_j; | |
793 | dentry->d_op = &pipefs_dentry_operations; | |
794 | d_add(dentry, inode); | |
795 | f1->f_vfsmnt = f2->f_vfsmnt = mntget(mntget(pipe_mnt)); | |
796 | f1->f_dentry = f2->f_dentry = dget(dentry); | |
797 | f1->f_mapping = f2->f_mapping = inode->i_mapping; | |
798 | ||
799 | /* read file */ | |
800 | f1->f_pos = f2->f_pos = 0; | |
801 | f1->f_flags = O_RDONLY; | |
802 | f1->f_op = &read_pipe_fops; | |
803 | f1->f_mode = FMODE_READ; | |
804 | f1->f_version = 0; | |
805 | ||
806 | /* write file */ | |
807 | f2->f_flags = O_WRONLY; | |
808 | f2->f_op = &write_pipe_fops; | |
809 | f2->f_mode = FMODE_WRITE; | |
810 | f2->f_version = 0; | |
811 | ||
812 | fd_install(i, f1); | |
813 | fd_install(j, f2); | |
814 | fd[0] = i; | |
815 | fd[1] = j; | |
816 | return 0; | |
817 | ||
818 | close_f12_inode_i_j: | |
819 | put_unused_fd(j); | |
820 | close_f12_inode_i: | |
821 | put_unused_fd(i); | |
822 | close_f12_inode: | |
823 | free_pipe_info(inode); | |
824 | iput(inode); | |
825 | close_f12: | |
826 | put_filp(f2); | |
827 | close_f1: | |
828 | put_filp(f1); | |
829 | no_files: | |
830 | return error; | |
831 | } | |
832 | ||
833 | /* | |
834 | * pipefs should _never_ be mounted by userland - too much of security hassle, | |
835 | * no real gain from having the whole whorehouse mounted. So we don't need | |
836 | * any operations on the root directory. However, we need a non-trivial | |
837 | * d_name - pipe: will go nicely and kill the special-casing in procfs. | |
838 | */ | |
839 | ||
840 | static struct super_block *pipefs_get_sb(struct file_system_type *fs_type, | |
841 | int flags, const char *dev_name, void *data) | |
842 | { | |
843 | return get_sb_pseudo(fs_type, "pipe:", NULL, PIPEFS_MAGIC); | |
844 | } | |
845 | ||
846 | static struct file_system_type pipe_fs_type = { | |
847 | .name = "pipefs", | |
848 | .get_sb = pipefs_get_sb, | |
849 | .kill_sb = kill_anon_super, | |
850 | }; | |
851 | ||
852 | static int __init init_pipe_fs(void) | |
853 | { | |
854 | int err = register_filesystem(&pipe_fs_type); | |
855 | if (!err) { | |
856 | pipe_mnt = kern_mount(&pipe_fs_type); | |
857 | if (IS_ERR(pipe_mnt)) { | |
858 | err = PTR_ERR(pipe_mnt); | |
859 | unregister_filesystem(&pipe_fs_type); | |
860 | } | |
861 | } | |
862 | return err; | |
863 | } | |
864 | ||
865 | static void __exit exit_pipe_fs(void) | |
866 | { | |
867 | unregister_filesystem(&pipe_fs_type); | |
868 | mntput(pipe_mnt); | |
869 | } | |
870 | ||
871 | fs_initcall(init_pipe_fs); | |
872 | module_exit(exit_pipe_fs); |