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 | */ | |
341b446b IM |
47 | prepare_to_wait(&pipe->wait, &wait, |
48 | TASK_INTERRUPTIBLE | TASK_NONINTERACTIVE); | |
3a326a2c IM |
49 | if (pipe->inode) |
50 | mutex_unlock(&pipe->inode->i_mutex); | |
1da177e4 | 51 | schedule(); |
3a326a2c IM |
52 | finish_wait(&pipe->wait, &wait); |
53 | if (pipe->inode) | |
54 | mutex_lock(&pipe->inode->i_mutex); | |
1da177e4 LT |
55 | } |
56 | ||
858119e1 | 57 | static int |
1da177e4 LT |
58 | pipe_iov_copy_from_user(void *to, struct iovec *iov, unsigned long len) |
59 | { | |
60 | unsigned long copy; | |
61 | ||
62 | while (len > 0) { | |
63 | while (!iov->iov_len) | |
64 | iov++; | |
65 | copy = min_t(unsigned long, len, iov->iov_len); | |
66 | ||
67 | if (copy_from_user(to, iov->iov_base, copy)) | |
68 | return -EFAULT; | |
69 | to += copy; | |
70 | len -= copy; | |
71 | iov->iov_base += copy; | |
72 | iov->iov_len -= copy; | |
73 | } | |
74 | return 0; | |
75 | } | |
76 | ||
858119e1 | 77 | static int |
1da177e4 LT |
78 | pipe_iov_copy_to_user(struct iovec *iov, const void *from, unsigned long len) |
79 | { | |
80 | unsigned long copy; | |
81 | ||
82 | while (len > 0) { | |
83 | while (!iov->iov_len) | |
84 | iov++; | |
85 | copy = min_t(unsigned long, len, iov->iov_len); | |
86 | ||
87 | if (copy_to_user(iov->iov_base, from, copy)) | |
88 | return -EFAULT; | |
89 | from += copy; | |
90 | len -= copy; | |
91 | iov->iov_base += copy; | |
92 | iov->iov_len -= copy; | |
93 | } | |
94 | return 0; | |
95 | } | |
96 | ||
341b446b IM |
97 | static void anon_pipe_buf_release(struct pipe_inode_info *pipe, |
98 | struct pipe_buffer *buf) | |
1da177e4 LT |
99 | { |
100 | struct page *page = buf->page; | |
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 | |
341b446b | 105 | * allocation cache. (Otherwise just release our reference to it) |
5274f052 | 106 | */ |
341b446b | 107 | if (page_count(page) == 1 && !pipe->tmp_page) |
923f4f23 | 108 | pipe->tmp_page = page; |
341b446b IM |
109 | else |
110 | page_cache_release(page); | |
1da177e4 LT |
111 | } |
112 | ||
341b446b IM |
113 | static void * anon_pipe_buf_map(struct file *file, struct pipe_inode_info *pipe, |
114 | struct pipe_buffer *buf) | |
1da177e4 LT |
115 | { |
116 | return kmap(buf->page); | |
117 | } | |
118 | ||
341b446b IM |
119 | static void anon_pipe_buf_unmap(struct pipe_inode_info *pipe, |
120 | struct pipe_buffer *buf) | |
1da177e4 LT |
121 | { |
122 | kunmap(buf->page); | |
123 | } | |
124 | ||
923f4f23 | 125 | static int anon_pipe_buf_steal(struct pipe_inode_info *pipe, |
5abc97aa JA |
126 | struct pipe_buffer *buf) |
127 | { | |
46e678c9 JA |
128 | struct page *page = buf->page; |
129 | ||
130 | if (page_count(page) == 1) { | |
46e678c9 JA |
131 | lock_page(page); |
132 | return 0; | |
133 | } | |
134 | ||
135 | return 1; | |
5abc97aa JA |
136 | } |
137 | ||
70524490 JA |
138 | static void anon_pipe_buf_get(struct pipe_inode_info *info, |
139 | struct pipe_buffer *buf) | |
140 | { | |
141 | page_cache_get(buf->page); | |
142 | } | |
143 | ||
1da177e4 LT |
144 | static struct pipe_buf_operations anon_pipe_buf_ops = { |
145 | .can_merge = 1, | |
146 | .map = anon_pipe_buf_map, | |
147 | .unmap = anon_pipe_buf_unmap, | |
148 | .release = anon_pipe_buf_release, | |
5abc97aa | 149 | .steal = anon_pipe_buf_steal, |
70524490 | 150 | .get = anon_pipe_buf_get, |
1da177e4 LT |
151 | }; |
152 | ||
153 | static ssize_t | |
154 | pipe_readv(struct file *filp, const struct iovec *_iov, | |
155 | unsigned long nr_segs, loff_t *ppos) | |
156 | { | |
157 | struct inode *inode = filp->f_dentry->d_inode; | |
923f4f23 | 158 | struct pipe_inode_info *pipe; |
1da177e4 LT |
159 | int do_wakeup; |
160 | ssize_t ret; | |
161 | struct iovec *iov = (struct iovec *)_iov; | |
162 | size_t total_len; | |
163 | ||
164 | total_len = iov_length(iov, nr_segs); | |
165 | /* Null read succeeds. */ | |
166 | if (unlikely(total_len == 0)) | |
167 | return 0; | |
168 | ||
169 | do_wakeup = 0; | |
170 | ret = 0; | |
9aeedfc4 | 171 | mutex_lock(&inode->i_mutex); |
923f4f23 | 172 | pipe = inode->i_pipe; |
1da177e4 | 173 | for (;;) { |
923f4f23 | 174 | int bufs = pipe->nrbufs; |
1da177e4 | 175 | if (bufs) { |
923f4f23 IM |
176 | int curbuf = pipe->curbuf; |
177 | struct pipe_buffer *buf = pipe->bufs + curbuf; | |
1da177e4 LT |
178 | struct pipe_buf_operations *ops = buf->ops; |
179 | void *addr; | |
180 | size_t chars = buf->len; | |
181 | int error; | |
182 | ||
183 | if (chars > total_len) | |
184 | chars = total_len; | |
185 | ||
923f4f23 | 186 | addr = ops->map(filp, pipe, buf); |
5274f052 JA |
187 | if (IS_ERR(addr)) { |
188 | if (!ret) | |
189 | ret = PTR_ERR(addr); | |
190 | break; | |
191 | } | |
1da177e4 | 192 | error = pipe_iov_copy_to_user(iov, addr + buf->offset, chars); |
923f4f23 | 193 | ops->unmap(pipe, buf); |
1da177e4 | 194 | if (unlikely(error)) { |
341b446b IM |
195 | if (!ret) |
196 | ret = -EFAULT; | |
1da177e4 LT |
197 | break; |
198 | } | |
199 | ret += chars; | |
200 | buf->offset += chars; | |
201 | buf->len -= chars; | |
202 | if (!buf->len) { | |
203 | buf->ops = NULL; | |
923f4f23 | 204 | ops->release(pipe, buf); |
1da177e4 | 205 | curbuf = (curbuf + 1) & (PIPE_BUFFERS-1); |
923f4f23 IM |
206 | pipe->curbuf = curbuf; |
207 | pipe->nrbufs = --bufs; | |
1da177e4 LT |
208 | do_wakeup = 1; |
209 | } | |
210 | total_len -= chars; | |
211 | if (!total_len) | |
212 | break; /* common path: read succeeded */ | |
213 | } | |
214 | if (bufs) /* More to do? */ | |
215 | continue; | |
923f4f23 | 216 | if (!pipe->writers) |
1da177e4 | 217 | break; |
923f4f23 | 218 | if (!pipe->waiting_writers) { |
1da177e4 LT |
219 | /* syscall merging: Usually we must not sleep |
220 | * if O_NONBLOCK is set, or if we got some data. | |
221 | * But if a writer sleeps in kernel space, then | |
222 | * we can wait for that data without violating POSIX. | |
223 | */ | |
224 | if (ret) | |
225 | break; | |
226 | if (filp->f_flags & O_NONBLOCK) { | |
227 | ret = -EAGAIN; | |
228 | break; | |
229 | } | |
230 | } | |
231 | if (signal_pending(current)) { | |
341b446b IM |
232 | if (!ret) |
233 | ret = -ERESTARTSYS; | |
1da177e4 LT |
234 | break; |
235 | } | |
236 | if (do_wakeup) { | |
923f4f23 IM |
237 | wake_up_interruptible_sync(&pipe->wait); |
238 | kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); | |
1da177e4 | 239 | } |
923f4f23 | 240 | pipe_wait(pipe); |
1da177e4 | 241 | } |
9aeedfc4 | 242 | mutex_unlock(&inode->i_mutex); |
341b446b IM |
243 | |
244 | /* Signal writers asynchronously that there is more room. */ | |
1da177e4 | 245 | if (do_wakeup) { |
923f4f23 IM |
246 | wake_up_interruptible(&pipe->wait); |
247 | kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); | |
1da177e4 LT |
248 | } |
249 | if (ret > 0) | |
250 | file_accessed(filp); | |
251 | return ret; | |
252 | } | |
253 | ||
254 | static ssize_t | |
255 | pipe_read(struct file *filp, char __user *buf, size_t count, loff_t *ppos) | |
256 | { | |
257 | struct iovec iov = { .iov_base = buf, .iov_len = count }; | |
341b446b | 258 | |
1da177e4 LT |
259 | return pipe_readv(filp, &iov, 1, ppos); |
260 | } | |
261 | ||
262 | static ssize_t | |
263 | pipe_writev(struct file *filp, const struct iovec *_iov, | |
264 | unsigned long nr_segs, loff_t *ppos) | |
265 | { | |
266 | struct inode *inode = filp->f_dentry->d_inode; | |
923f4f23 | 267 | struct pipe_inode_info *pipe; |
1da177e4 LT |
268 | ssize_t ret; |
269 | int do_wakeup; | |
270 | struct iovec *iov = (struct iovec *)_iov; | |
271 | size_t total_len; | |
272 | ssize_t chars; | |
273 | ||
274 | total_len = iov_length(iov, nr_segs); | |
275 | /* Null write succeeds. */ | |
276 | if (unlikely(total_len == 0)) | |
277 | return 0; | |
278 | ||
279 | do_wakeup = 0; | |
280 | ret = 0; | |
9aeedfc4 | 281 | mutex_lock(&inode->i_mutex); |
923f4f23 | 282 | pipe = inode->i_pipe; |
1da177e4 | 283 | |
923f4f23 | 284 | if (!pipe->readers) { |
1da177e4 LT |
285 | send_sig(SIGPIPE, current, 0); |
286 | ret = -EPIPE; | |
287 | goto out; | |
288 | } | |
289 | ||
290 | /* We try to merge small writes */ | |
291 | chars = total_len & (PAGE_SIZE-1); /* size of the last buffer */ | |
923f4f23 | 292 | if (pipe->nrbufs && chars != 0) { |
341b446b IM |
293 | int lastbuf = (pipe->curbuf + pipe->nrbufs - 1) & |
294 | (PIPE_BUFFERS-1); | |
923f4f23 | 295 | struct pipe_buffer *buf = pipe->bufs + lastbuf; |
1da177e4 LT |
296 | struct pipe_buf_operations *ops = buf->ops; |
297 | int offset = buf->offset + buf->len; | |
341b446b | 298 | |
1da177e4 | 299 | if (ops->can_merge && offset + chars <= PAGE_SIZE) { |
5274f052 JA |
300 | void *addr; |
301 | int error; | |
302 | ||
923f4f23 | 303 | addr = ops->map(filp, pipe, buf); |
5274f052 JA |
304 | if (IS_ERR(addr)) { |
305 | error = PTR_ERR(addr); | |
306 | goto out; | |
307 | } | |
308 | error = pipe_iov_copy_from_user(offset + addr, iov, | |
309 | chars); | |
923f4f23 | 310 | ops->unmap(pipe, buf); |
1da177e4 LT |
311 | ret = error; |
312 | do_wakeup = 1; | |
313 | if (error) | |
314 | goto out; | |
315 | buf->len += chars; | |
316 | total_len -= chars; | |
317 | ret = chars; | |
318 | if (!total_len) | |
319 | goto out; | |
320 | } | |
321 | } | |
322 | ||
323 | for (;;) { | |
324 | int bufs; | |
341b446b | 325 | |
923f4f23 | 326 | if (!pipe->readers) { |
1da177e4 | 327 | send_sig(SIGPIPE, current, 0); |
341b446b IM |
328 | if (!ret) |
329 | ret = -EPIPE; | |
1da177e4 LT |
330 | break; |
331 | } | |
923f4f23 | 332 | bufs = pipe->nrbufs; |
1da177e4 | 333 | if (bufs < PIPE_BUFFERS) { |
923f4f23 IM |
334 | int newbuf = (pipe->curbuf + bufs) & (PIPE_BUFFERS-1); |
335 | struct pipe_buffer *buf = pipe->bufs + newbuf; | |
336 | struct page *page = pipe->tmp_page; | |
1da177e4 LT |
337 | int error; |
338 | ||
339 | if (!page) { | |
340 | page = alloc_page(GFP_HIGHUSER); | |
341 | if (unlikely(!page)) { | |
342 | ret = ret ? : -ENOMEM; | |
343 | break; | |
344 | } | |
923f4f23 | 345 | pipe->tmp_page = page; |
1da177e4 | 346 | } |
341b446b | 347 | /* Always wake up, even if the copy fails. Otherwise |
1da177e4 LT |
348 | * we lock up (O_NONBLOCK-)readers that sleep due to |
349 | * syscall merging. | |
350 | * FIXME! Is this really true? | |
351 | */ | |
352 | do_wakeup = 1; | |
353 | chars = PAGE_SIZE; | |
354 | if (chars > total_len) | |
355 | chars = total_len; | |
356 | ||
357 | error = pipe_iov_copy_from_user(kmap(page), iov, chars); | |
358 | kunmap(page); | |
359 | if (unlikely(error)) { | |
341b446b IM |
360 | if (!ret) |
361 | ret = -EFAULT; | |
1da177e4 LT |
362 | break; |
363 | } | |
364 | ret += chars; | |
365 | ||
366 | /* Insert it into the buffer array */ | |
367 | buf->page = page; | |
368 | buf->ops = &anon_pipe_buf_ops; | |
369 | buf->offset = 0; | |
370 | buf->len = chars; | |
923f4f23 IM |
371 | pipe->nrbufs = ++bufs; |
372 | pipe->tmp_page = NULL; | |
1da177e4 LT |
373 | |
374 | total_len -= chars; | |
375 | if (!total_len) | |
376 | break; | |
377 | } | |
378 | if (bufs < PIPE_BUFFERS) | |
379 | continue; | |
380 | if (filp->f_flags & O_NONBLOCK) { | |
341b446b IM |
381 | if (!ret) |
382 | ret = -EAGAIN; | |
1da177e4 LT |
383 | break; |
384 | } | |
385 | if (signal_pending(current)) { | |
341b446b IM |
386 | if (!ret) |
387 | ret = -ERESTARTSYS; | |
1da177e4 LT |
388 | break; |
389 | } | |
390 | if (do_wakeup) { | |
923f4f23 IM |
391 | wake_up_interruptible_sync(&pipe->wait); |
392 | kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); | |
1da177e4 LT |
393 | do_wakeup = 0; |
394 | } | |
923f4f23 IM |
395 | pipe->waiting_writers++; |
396 | pipe_wait(pipe); | |
397 | pipe->waiting_writers--; | |
1da177e4 LT |
398 | } |
399 | out: | |
9aeedfc4 | 400 | mutex_unlock(&inode->i_mutex); |
1da177e4 | 401 | if (do_wakeup) { |
923f4f23 IM |
402 | wake_up_interruptible(&pipe->wait); |
403 | kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); | |
1da177e4 LT |
404 | } |
405 | if (ret > 0) | |
870f4817 | 406 | file_update_time(filp); |
1da177e4 LT |
407 | return ret; |
408 | } | |
409 | ||
410 | static ssize_t | |
411 | pipe_write(struct file *filp, const char __user *buf, | |
412 | size_t count, loff_t *ppos) | |
413 | { | |
414 | struct iovec iov = { .iov_base = (void __user *)buf, .iov_len = count }; | |
341b446b | 415 | |
1da177e4 LT |
416 | return pipe_writev(filp, &iov, 1, ppos); |
417 | } | |
418 | ||
419 | static ssize_t | |
420 | bad_pipe_r(struct file *filp, char __user *buf, size_t count, loff_t *ppos) | |
421 | { | |
422 | return -EBADF; | |
423 | } | |
424 | ||
425 | static ssize_t | |
341b446b IM |
426 | bad_pipe_w(struct file *filp, const char __user *buf, size_t count, |
427 | loff_t *ppos) | |
1da177e4 LT |
428 | { |
429 | return -EBADF; | |
430 | } | |
431 | ||
432 | static int | |
433 | pipe_ioctl(struct inode *pino, struct file *filp, | |
434 | unsigned int cmd, unsigned long arg) | |
435 | { | |
436 | struct inode *inode = filp->f_dentry->d_inode; | |
923f4f23 | 437 | struct pipe_inode_info *pipe; |
1da177e4 LT |
438 | int count, buf, nrbufs; |
439 | ||
440 | switch (cmd) { | |
441 | case FIONREAD: | |
9aeedfc4 | 442 | mutex_lock(&inode->i_mutex); |
923f4f23 | 443 | pipe = inode->i_pipe; |
1da177e4 | 444 | count = 0; |
923f4f23 IM |
445 | buf = pipe->curbuf; |
446 | nrbufs = pipe->nrbufs; | |
1da177e4 | 447 | while (--nrbufs >= 0) { |
923f4f23 | 448 | count += pipe->bufs[buf].len; |
1da177e4 LT |
449 | buf = (buf+1) & (PIPE_BUFFERS-1); |
450 | } | |
9aeedfc4 | 451 | mutex_unlock(&inode->i_mutex); |
923f4f23 | 452 | |
1da177e4 LT |
453 | return put_user(count, (int __user *)arg); |
454 | default: | |
455 | return -EINVAL; | |
456 | } | |
457 | } | |
458 | ||
459 | /* No kernel lock held - fine */ | |
460 | static unsigned int | |
461 | pipe_poll(struct file *filp, poll_table *wait) | |
462 | { | |
463 | unsigned int mask; | |
464 | struct inode *inode = filp->f_dentry->d_inode; | |
923f4f23 | 465 | struct pipe_inode_info *pipe = inode->i_pipe; |
1da177e4 LT |
466 | int nrbufs; |
467 | ||
923f4f23 | 468 | poll_wait(filp, &pipe->wait, wait); |
1da177e4 LT |
469 | |
470 | /* Reading only -- no need for acquiring the semaphore. */ | |
923f4f23 | 471 | nrbufs = pipe->nrbufs; |
1da177e4 LT |
472 | mask = 0; |
473 | if (filp->f_mode & FMODE_READ) { | |
474 | mask = (nrbufs > 0) ? POLLIN | POLLRDNORM : 0; | |
923f4f23 | 475 | if (!pipe->writers && filp->f_version != pipe->w_counter) |
1da177e4 LT |
476 | mask |= POLLHUP; |
477 | } | |
478 | ||
479 | if (filp->f_mode & FMODE_WRITE) { | |
480 | mask |= (nrbufs < PIPE_BUFFERS) ? POLLOUT | POLLWRNORM : 0; | |
5e5d7a22 PE |
481 | /* |
482 | * Most Unices do not set POLLERR for FIFOs but on Linux they | |
483 | * behave exactly like pipes for poll(). | |
484 | */ | |
923f4f23 | 485 | if (!pipe->readers) |
1da177e4 LT |
486 | mask |= POLLERR; |
487 | } | |
488 | ||
489 | return mask; | |
490 | } | |
491 | ||
1da177e4 LT |
492 | static int |
493 | pipe_release(struct inode *inode, int decr, int decw) | |
494 | { | |
923f4f23 IM |
495 | struct pipe_inode_info *pipe; |
496 | ||
9aeedfc4 | 497 | mutex_lock(&inode->i_mutex); |
923f4f23 IM |
498 | pipe = inode->i_pipe; |
499 | pipe->readers -= decr; | |
500 | pipe->writers -= decw; | |
341b446b | 501 | |
923f4f23 | 502 | if (!pipe->readers && !pipe->writers) { |
1da177e4 LT |
503 | free_pipe_info(inode); |
504 | } else { | |
923f4f23 IM |
505 | wake_up_interruptible(&pipe->wait); |
506 | kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); | |
507 | kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); | |
1da177e4 | 508 | } |
9aeedfc4 | 509 | mutex_unlock(&inode->i_mutex); |
1da177e4 LT |
510 | |
511 | return 0; | |
512 | } | |
513 | ||
514 | static int | |
515 | pipe_read_fasync(int fd, struct file *filp, int on) | |
516 | { | |
517 | struct inode *inode = filp->f_dentry->d_inode; | |
518 | int retval; | |
519 | ||
9aeedfc4 IM |
520 | mutex_lock(&inode->i_mutex); |
521 | retval = fasync_helper(fd, filp, on, &inode->i_pipe->fasync_readers); | |
522 | mutex_unlock(&inode->i_mutex); | |
1da177e4 LT |
523 | |
524 | if (retval < 0) | |
525 | return retval; | |
526 | ||
527 | return 0; | |
528 | } | |
529 | ||
530 | ||
531 | static int | |
532 | pipe_write_fasync(int fd, struct file *filp, int on) | |
533 | { | |
534 | struct inode *inode = filp->f_dentry->d_inode; | |
535 | int retval; | |
536 | ||
9aeedfc4 IM |
537 | mutex_lock(&inode->i_mutex); |
538 | retval = fasync_helper(fd, filp, on, &inode->i_pipe->fasync_writers); | |
539 | mutex_unlock(&inode->i_mutex); | |
1da177e4 LT |
540 | |
541 | if (retval < 0) | |
542 | return retval; | |
543 | ||
544 | return 0; | |
545 | } | |
546 | ||
547 | ||
548 | static int | |
549 | pipe_rdwr_fasync(int fd, struct file *filp, int on) | |
550 | { | |
551 | struct inode *inode = filp->f_dentry->d_inode; | |
341b446b | 552 | struct pipe_inode_info *pipe = inode->i_pipe; |
1da177e4 LT |
553 | int retval; |
554 | ||
9aeedfc4 | 555 | mutex_lock(&inode->i_mutex); |
1da177e4 | 556 | |
341b446b | 557 | retval = fasync_helper(fd, filp, on, &pipe->fasync_readers); |
1da177e4 LT |
558 | |
559 | if (retval >= 0) | |
341b446b | 560 | retval = fasync_helper(fd, filp, on, &pipe->fasync_writers); |
1da177e4 | 561 | |
9aeedfc4 | 562 | mutex_unlock(&inode->i_mutex); |
1da177e4 LT |
563 | |
564 | if (retval < 0) | |
565 | return retval; | |
566 | ||
567 | return 0; | |
568 | } | |
569 | ||
570 | ||
571 | static int | |
572 | pipe_read_release(struct inode *inode, struct file *filp) | |
573 | { | |
574 | pipe_read_fasync(-1, filp, 0); | |
575 | return pipe_release(inode, 1, 0); | |
576 | } | |
577 | ||
578 | static int | |
579 | pipe_write_release(struct inode *inode, struct file *filp) | |
580 | { | |
581 | pipe_write_fasync(-1, filp, 0); | |
582 | return pipe_release(inode, 0, 1); | |
583 | } | |
584 | ||
585 | static int | |
586 | pipe_rdwr_release(struct inode *inode, struct file *filp) | |
587 | { | |
588 | int decr, decw; | |
589 | ||
590 | pipe_rdwr_fasync(-1, filp, 0); | |
591 | decr = (filp->f_mode & FMODE_READ) != 0; | |
592 | decw = (filp->f_mode & FMODE_WRITE) != 0; | |
593 | return pipe_release(inode, decr, decw); | |
594 | } | |
595 | ||
596 | static int | |
597 | pipe_read_open(struct inode *inode, struct file *filp) | |
598 | { | |
599 | /* We could have perhaps used atomic_t, but this and friends | |
600 | below are the only places. So it doesn't seem worthwhile. */ | |
9aeedfc4 IM |
601 | mutex_lock(&inode->i_mutex); |
602 | inode->i_pipe->readers++; | |
603 | mutex_unlock(&inode->i_mutex); | |
1da177e4 LT |
604 | |
605 | return 0; | |
606 | } | |
607 | ||
608 | static int | |
609 | pipe_write_open(struct inode *inode, struct file *filp) | |
610 | { | |
9aeedfc4 IM |
611 | mutex_lock(&inode->i_mutex); |
612 | inode->i_pipe->writers++; | |
613 | mutex_unlock(&inode->i_mutex); | |
1da177e4 LT |
614 | |
615 | return 0; | |
616 | } | |
617 | ||
618 | static int | |
619 | pipe_rdwr_open(struct inode *inode, struct file *filp) | |
620 | { | |
9aeedfc4 | 621 | mutex_lock(&inode->i_mutex); |
1da177e4 | 622 | if (filp->f_mode & FMODE_READ) |
9aeedfc4 | 623 | inode->i_pipe->readers++; |
1da177e4 | 624 | if (filp->f_mode & FMODE_WRITE) |
9aeedfc4 IM |
625 | inode->i_pipe->writers++; |
626 | mutex_unlock(&inode->i_mutex); | |
1da177e4 LT |
627 | |
628 | return 0; | |
629 | } | |
630 | ||
631 | /* | |
632 | * The file_operations structs are not static because they | |
633 | * are also used in linux/fs/fifo.c to do operations on FIFOs. | |
634 | */ | |
4b6f5d20 | 635 | const struct file_operations read_fifo_fops = { |
1da177e4 LT |
636 | .llseek = no_llseek, |
637 | .read = pipe_read, | |
638 | .readv = pipe_readv, | |
639 | .write = bad_pipe_w, | |
5e5d7a22 | 640 | .poll = pipe_poll, |
1da177e4 LT |
641 | .ioctl = pipe_ioctl, |
642 | .open = pipe_read_open, | |
643 | .release = pipe_read_release, | |
644 | .fasync = pipe_read_fasync, | |
645 | }; | |
646 | ||
4b6f5d20 | 647 | const struct file_operations write_fifo_fops = { |
1da177e4 LT |
648 | .llseek = no_llseek, |
649 | .read = bad_pipe_r, | |
650 | .write = pipe_write, | |
651 | .writev = pipe_writev, | |
5e5d7a22 | 652 | .poll = pipe_poll, |
1da177e4 LT |
653 | .ioctl = pipe_ioctl, |
654 | .open = pipe_write_open, | |
655 | .release = pipe_write_release, | |
656 | .fasync = pipe_write_fasync, | |
657 | }; | |
658 | ||
4b6f5d20 | 659 | const struct file_operations rdwr_fifo_fops = { |
1da177e4 LT |
660 | .llseek = no_llseek, |
661 | .read = pipe_read, | |
662 | .readv = pipe_readv, | |
663 | .write = pipe_write, | |
664 | .writev = pipe_writev, | |
5e5d7a22 | 665 | .poll = pipe_poll, |
1da177e4 LT |
666 | .ioctl = pipe_ioctl, |
667 | .open = pipe_rdwr_open, | |
668 | .release = pipe_rdwr_release, | |
669 | .fasync = pipe_rdwr_fasync, | |
670 | }; | |
671 | ||
a19cbd4b | 672 | static struct file_operations read_pipe_fops = { |
1da177e4 LT |
673 | .llseek = no_llseek, |
674 | .read = pipe_read, | |
675 | .readv = pipe_readv, | |
676 | .write = bad_pipe_w, | |
677 | .poll = pipe_poll, | |
678 | .ioctl = pipe_ioctl, | |
679 | .open = pipe_read_open, | |
680 | .release = pipe_read_release, | |
681 | .fasync = pipe_read_fasync, | |
682 | }; | |
683 | ||
a19cbd4b | 684 | static struct file_operations write_pipe_fops = { |
1da177e4 LT |
685 | .llseek = no_llseek, |
686 | .read = bad_pipe_r, | |
687 | .write = pipe_write, | |
688 | .writev = pipe_writev, | |
689 | .poll = pipe_poll, | |
690 | .ioctl = pipe_ioctl, | |
691 | .open = pipe_write_open, | |
692 | .release = pipe_write_release, | |
693 | .fasync = pipe_write_fasync, | |
694 | }; | |
695 | ||
a19cbd4b | 696 | static struct file_operations rdwr_pipe_fops = { |
1da177e4 LT |
697 | .llseek = no_llseek, |
698 | .read = pipe_read, | |
699 | .readv = pipe_readv, | |
700 | .write = pipe_write, | |
701 | .writev = pipe_writev, | |
702 | .poll = pipe_poll, | |
703 | .ioctl = pipe_ioctl, | |
704 | .open = pipe_rdwr_open, | |
705 | .release = pipe_rdwr_release, | |
706 | .fasync = pipe_rdwr_fasync, | |
707 | }; | |
708 | ||
3a326a2c IM |
709 | struct pipe_inode_info * alloc_pipe_info(struct inode *inode) |
710 | { | |
923f4f23 | 711 | struct pipe_inode_info *pipe; |
3a326a2c | 712 | |
923f4f23 IM |
713 | pipe = kzalloc(sizeof(struct pipe_inode_info), GFP_KERNEL); |
714 | if (pipe) { | |
715 | init_waitqueue_head(&pipe->wait); | |
716 | pipe->r_counter = pipe->w_counter = 1; | |
717 | pipe->inode = inode; | |
3a326a2c IM |
718 | } |
719 | ||
923f4f23 | 720 | return pipe; |
3a326a2c IM |
721 | } |
722 | ||
923f4f23 | 723 | void __free_pipe_info(struct pipe_inode_info *pipe) |
1da177e4 LT |
724 | { |
725 | int i; | |
1da177e4 | 726 | |
1da177e4 | 727 | for (i = 0; i < PIPE_BUFFERS; i++) { |
923f4f23 | 728 | struct pipe_buffer *buf = pipe->bufs + i; |
1da177e4 | 729 | if (buf->ops) |
923f4f23 | 730 | buf->ops->release(pipe, buf); |
1da177e4 | 731 | } |
923f4f23 IM |
732 | if (pipe->tmp_page) |
733 | __free_page(pipe->tmp_page); | |
734 | kfree(pipe); | |
1da177e4 LT |
735 | } |
736 | ||
b92ce558 JA |
737 | void free_pipe_info(struct inode *inode) |
738 | { | |
739 | __free_pipe_info(inode->i_pipe); | |
740 | inode->i_pipe = NULL; | |
741 | } | |
742 | ||
fa3536cc | 743 | static struct vfsmount *pipe_mnt __read_mostly; |
1da177e4 LT |
744 | static int pipefs_delete_dentry(struct dentry *dentry) |
745 | { | |
746 | return 1; | |
747 | } | |
341b446b | 748 | |
1da177e4 LT |
749 | static struct dentry_operations pipefs_dentry_operations = { |
750 | .d_delete = pipefs_delete_dentry, | |
751 | }; | |
752 | ||
753 | static struct inode * get_pipe_inode(void) | |
754 | { | |
755 | struct inode *inode = new_inode(pipe_mnt->mnt_sb); | |
923f4f23 | 756 | struct pipe_inode_info *pipe; |
1da177e4 LT |
757 | |
758 | if (!inode) | |
759 | goto fail_inode; | |
760 | ||
923f4f23 IM |
761 | pipe = alloc_pipe_info(inode); |
762 | if (!pipe) | |
1da177e4 | 763 | goto fail_iput; |
923f4f23 | 764 | inode->i_pipe = pipe; |
3a326a2c | 765 | |
923f4f23 | 766 | pipe->readers = pipe->writers = 1; |
1da177e4 LT |
767 | inode->i_fop = &rdwr_pipe_fops; |
768 | ||
769 | /* | |
770 | * Mark the inode dirty from the very beginning, | |
771 | * that way it will never be moved to the dirty | |
772 | * list because "mark_inode_dirty()" will think | |
773 | * that it already _is_ on the dirty list. | |
774 | */ | |
775 | inode->i_state = I_DIRTY; | |
776 | inode->i_mode = S_IFIFO | S_IRUSR | S_IWUSR; | |
777 | inode->i_uid = current->fsuid; | |
778 | inode->i_gid = current->fsgid; | |
779 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; | |
780 | inode->i_blksize = PAGE_SIZE; | |
923f4f23 | 781 | |
1da177e4 LT |
782 | return inode; |
783 | ||
784 | fail_iput: | |
785 | iput(inode); | |
341b446b | 786 | |
1da177e4 LT |
787 | fail_inode: |
788 | return NULL; | |
789 | } | |
790 | ||
791 | int do_pipe(int *fd) | |
792 | { | |
793 | struct qstr this; | |
794 | char name[32]; | |
795 | struct dentry *dentry; | |
796 | struct inode * inode; | |
797 | struct file *f1, *f2; | |
798 | int error; | |
341b446b | 799 | int i, j; |
1da177e4 LT |
800 | |
801 | error = -ENFILE; | |
802 | f1 = get_empty_filp(); | |
803 | if (!f1) | |
804 | goto no_files; | |
805 | ||
806 | f2 = get_empty_filp(); | |
807 | if (!f2) | |
808 | goto close_f1; | |
809 | ||
810 | inode = get_pipe_inode(); | |
811 | if (!inode) | |
812 | goto close_f12; | |
813 | ||
814 | error = get_unused_fd(); | |
815 | if (error < 0) | |
816 | goto close_f12_inode; | |
817 | i = error; | |
818 | ||
819 | error = get_unused_fd(); | |
820 | if (error < 0) | |
821 | goto close_f12_inode_i; | |
822 | j = error; | |
823 | ||
824 | error = -ENOMEM; | |
825 | sprintf(name, "[%lu]", inode->i_ino); | |
826 | this.name = name; | |
827 | this.len = strlen(name); | |
828 | this.hash = inode->i_ino; /* will go */ | |
829 | dentry = d_alloc(pipe_mnt->mnt_sb->s_root, &this); | |
830 | if (!dentry) | |
831 | goto close_f12_inode_i_j; | |
341b446b | 832 | |
1da177e4 LT |
833 | dentry->d_op = &pipefs_dentry_operations; |
834 | d_add(dentry, inode); | |
835 | f1->f_vfsmnt = f2->f_vfsmnt = mntget(mntget(pipe_mnt)); | |
836 | f1->f_dentry = f2->f_dentry = dget(dentry); | |
837 | f1->f_mapping = f2->f_mapping = inode->i_mapping; | |
838 | ||
839 | /* read file */ | |
840 | f1->f_pos = f2->f_pos = 0; | |
841 | f1->f_flags = O_RDONLY; | |
842 | f1->f_op = &read_pipe_fops; | |
843 | f1->f_mode = FMODE_READ; | |
844 | f1->f_version = 0; | |
845 | ||
846 | /* write file */ | |
847 | f2->f_flags = O_WRONLY; | |
848 | f2->f_op = &write_pipe_fops; | |
849 | f2->f_mode = FMODE_WRITE; | |
850 | f2->f_version = 0; | |
851 | ||
852 | fd_install(i, f1); | |
853 | fd_install(j, f2); | |
854 | fd[0] = i; | |
855 | fd[1] = j; | |
341b446b | 856 | |
1da177e4 LT |
857 | return 0; |
858 | ||
859 | close_f12_inode_i_j: | |
860 | put_unused_fd(j); | |
861 | close_f12_inode_i: | |
862 | put_unused_fd(i); | |
863 | close_f12_inode: | |
864 | free_pipe_info(inode); | |
865 | iput(inode); | |
866 | close_f12: | |
867 | put_filp(f2); | |
868 | close_f1: | |
869 | put_filp(f1); | |
870 | no_files: | |
871 | return error; | |
872 | } | |
873 | ||
874 | /* | |
875 | * pipefs should _never_ be mounted by userland - too much of security hassle, | |
876 | * no real gain from having the whole whorehouse mounted. So we don't need | |
877 | * any operations on the root directory. However, we need a non-trivial | |
878 | * d_name - pipe: will go nicely and kill the special-casing in procfs. | |
879 | */ | |
880 | ||
341b446b IM |
881 | static struct super_block * |
882 | pipefs_get_sb(struct file_system_type *fs_type, int flags, | |
883 | const char *dev_name, void *data) | |
1da177e4 LT |
884 | { |
885 | return get_sb_pseudo(fs_type, "pipe:", NULL, PIPEFS_MAGIC); | |
886 | } | |
887 | ||
888 | static struct file_system_type pipe_fs_type = { | |
889 | .name = "pipefs", | |
890 | .get_sb = pipefs_get_sb, | |
891 | .kill_sb = kill_anon_super, | |
892 | }; | |
893 | ||
894 | static int __init init_pipe_fs(void) | |
895 | { | |
896 | int err = register_filesystem(&pipe_fs_type); | |
341b446b | 897 | |
1da177e4 LT |
898 | if (!err) { |
899 | pipe_mnt = kern_mount(&pipe_fs_type); | |
900 | if (IS_ERR(pipe_mnt)) { | |
901 | err = PTR_ERR(pipe_mnt); | |
902 | unregister_filesystem(&pipe_fs_type); | |
903 | } | |
904 | } | |
905 | return err; | |
906 | } | |
907 | ||
908 | static void __exit exit_pipe_fs(void) | |
909 | { | |
910 | unregister_filesystem(&pipe_fs_type); | |
911 | mntput(pipe_mnt); | |
912 | } | |
913 | ||
914 | fs_initcall(init_pipe_fs); | |
915 | module_exit(exit_pipe_fs); |