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 | ||
3e7ee3e7 JA |
102 | buf->flags &= ~PIPE_BUF_FLAG_STOLEN; |
103 | ||
5274f052 JA |
104 | /* |
105 | * If nobody else uses this page, and we don't already have a | |
106 | * temporary page, let's keep track of it as a one-deep | |
341b446b | 107 | * allocation cache. (Otherwise just release our reference to it) |
5274f052 | 108 | */ |
341b446b | 109 | if (page_count(page) == 1 && !pipe->tmp_page) |
923f4f23 | 110 | pipe->tmp_page = page; |
341b446b IM |
111 | else |
112 | page_cache_release(page); | |
1da177e4 LT |
113 | } |
114 | ||
341b446b IM |
115 | static void * anon_pipe_buf_map(struct file *file, struct pipe_inode_info *pipe, |
116 | struct pipe_buffer *buf) | |
1da177e4 LT |
117 | { |
118 | return kmap(buf->page); | |
119 | } | |
120 | ||
341b446b IM |
121 | static void anon_pipe_buf_unmap(struct pipe_inode_info *pipe, |
122 | struct pipe_buffer *buf) | |
1da177e4 LT |
123 | { |
124 | kunmap(buf->page); | |
125 | } | |
126 | ||
923f4f23 | 127 | static int anon_pipe_buf_steal(struct pipe_inode_info *pipe, |
5abc97aa JA |
128 | struct pipe_buffer *buf) |
129 | { | |
3e7ee3e7 | 130 | buf->flags |= PIPE_BUF_FLAG_STOLEN; |
5abc97aa JA |
131 | return 0; |
132 | } | |
133 | ||
70524490 JA |
134 | static void anon_pipe_buf_get(struct pipe_inode_info *info, |
135 | struct pipe_buffer *buf) | |
136 | { | |
137 | page_cache_get(buf->page); | |
138 | } | |
139 | ||
1da177e4 LT |
140 | static struct pipe_buf_operations anon_pipe_buf_ops = { |
141 | .can_merge = 1, | |
142 | .map = anon_pipe_buf_map, | |
143 | .unmap = anon_pipe_buf_unmap, | |
144 | .release = anon_pipe_buf_release, | |
5abc97aa | 145 | .steal = anon_pipe_buf_steal, |
70524490 | 146 | .get = anon_pipe_buf_get, |
1da177e4 LT |
147 | }; |
148 | ||
149 | static ssize_t | |
150 | pipe_readv(struct file *filp, const struct iovec *_iov, | |
151 | unsigned long nr_segs, loff_t *ppos) | |
152 | { | |
153 | struct inode *inode = filp->f_dentry->d_inode; | |
923f4f23 | 154 | struct pipe_inode_info *pipe; |
1da177e4 LT |
155 | int do_wakeup; |
156 | ssize_t ret; | |
157 | struct iovec *iov = (struct iovec *)_iov; | |
158 | size_t total_len; | |
159 | ||
160 | total_len = iov_length(iov, nr_segs); | |
161 | /* Null read succeeds. */ | |
162 | if (unlikely(total_len == 0)) | |
163 | return 0; | |
164 | ||
165 | do_wakeup = 0; | |
166 | ret = 0; | |
9aeedfc4 | 167 | mutex_lock(&inode->i_mutex); |
923f4f23 | 168 | pipe = inode->i_pipe; |
1da177e4 | 169 | for (;;) { |
923f4f23 | 170 | int bufs = pipe->nrbufs; |
1da177e4 | 171 | if (bufs) { |
923f4f23 IM |
172 | int curbuf = pipe->curbuf; |
173 | struct pipe_buffer *buf = pipe->bufs + curbuf; | |
1da177e4 LT |
174 | struct pipe_buf_operations *ops = buf->ops; |
175 | void *addr; | |
176 | size_t chars = buf->len; | |
177 | int error; | |
178 | ||
179 | if (chars > total_len) | |
180 | chars = total_len; | |
181 | ||
923f4f23 | 182 | addr = ops->map(filp, pipe, buf); |
5274f052 JA |
183 | if (IS_ERR(addr)) { |
184 | if (!ret) | |
185 | ret = PTR_ERR(addr); | |
186 | break; | |
187 | } | |
1da177e4 | 188 | error = pipe_iov_copy_to_user(iov, addr + buf->offset, chars); |
923f4f23 | 189 | ops->unmap(pipe, buf); |
1da177e4 | 190 | if (unlikely(error)) { |
341b446b IM |
191 | if (!ret) |
192 | ret = -EFAULT; | |
1da177e4 LT |
193 | break; |
194 | } | |
195 | ret += chars; | |
196 | buf->offset += chars; | |
197 | buf->len -= chars; | |
198 | if (!buf->len) { | |
199 | buf->ops = NULL; | |
923f4f23 | 200 | ops->release(pipe, buf); |
1da177e4 | 201 | curbuf = (curbuf + 1) & (PIPE_BUFFERS-1); |
923f4f23 IM |
202 | pipe->curbuf = curbuf; |
203 | pipe->nrbufs = --bufs; | |
1da177e4 LT |
204 | do_wakeup = 1; |
205 | } | |
206 | total_len -= chars; | |
207 | if (!total_len) | |
208 | break; /* common path: read succeeded */ | |
209 | } | |
210 | if (bufs) /* More to do? */ | |
211 | continue; | |
923f4f23 | 212 | if (!pipe->writers) |
1da177e4 | 213 | break; |
923f4f23 | 214 | if (!pipe->waiting_writers) { |
1da177e4 LT |
215 | /* syscall merging: Usually we must not sleep |
216 | * if O_NONBLOCK is set, or if we got some data. | |
217 | * But if a writer sleeps in kernel space, then | |
218 | * we can wait for that data without violating POSIX. | |
219 | */ | |
220 | if (ret) | |
221 | break; | |
222 | if (filp->f_flags & O_NONBLOCK) { | |
223 | ret = -EAGAIN; | |
224 | break; | |
225 | } | |
226 | } | |
227 | if (signal_pending(current)) { | |
341b446b IM |
228 | if (!ret) |
229 | ret = -ERESTARTSYS; | |
1da177e4 LT |
230 | break; |
231 | } | |
232 | if (do_wakeup) { | |
923f4f23 IM |
233 | wake_up_interruptible_sync(&pipe->wait); |
234 | kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); | |
1da177e4 | 235 | } |
923f4f23 | 236 | pipe_wait(pipe); |
1da177e4 | 237 | } |
9aeedfc4 | 238 | mutex_unlock(&inode->i_mutex); |
341b446b IM |
239 | |
240 | /* Signal writers asynchronously that there is more room. */ | |
1da177e4 | 241 | if (do_wakeup) { |
923f4f23 IM |
242 | wake_up_interruptible(&pipe->wait); |
243 | kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); | |
1da177e4 LT |
244 | } |
245 | if (ret > 0) | |
246 | file_accessed(filp); | |
247 | return ret; | |
248 | } | |
249 | ||
250 | static ssize_t | |
251 | pipe_read(struct file *filp, char __user *buf, size_t count, loff_t *ppos) | |
252 | { | |
253 | struct iovec iov = { .iov_base = buf, .iov_len = count }; | |
341b446b | 254 | |
1da177e4 LT |
255 | return pipe_readv(filp, &iov, 1, ppos); |
256 | } | |
257 | ||
258 | static ssize_t | |
259 | pipe_writev(struct file *filp, const struct iovec *_iov, | |
260 | unsigned long nr_segs, loff_t *ppos) | |
261 | { | |
262 | struct inode *inode = filp->f_dentry->d_inode; | |
923f4f23 | 263 | struct pipe_inode_info *pipe; |
1da177e4 LT |
264 | ssize_t ret; |
265 | int do_wakeup; | |
266 | struct iovec *iov = (struct iovec *)_iov; | |
267 | size_t total_len; | |
268 | ssize_t chars; | |
269 | ||
270 | total_len = iov_length(iov, nr_segs); | |
271 | /* Null write succeeds. */ | |
272 | if (unlikely(total_len == 0)) | |
273 | return 0; | |
274 | ||
275 | do_wakeup = 0; | |
276 | ret = 0; | |
9aeedfc4 | 277 | mutex_lock(&inode->i_mutex); |
923f4f23 | 278 | pipe = inode->i_pipe; |
1da177e4 | 279 | |
923f4f23 | 280 | if (!pipe->readers) { |
1da177e4 LT |
281 | send_sig(SIGPIPE, current, 0); |
282 | ret = -EPIPE; | |
283 | goto out; | |
284 | } | |
285 | ||
286 | /* We try to merge small writes */ | |
287 | chars = total_len & (PAGE_SIZE-1); /* size of the last buffer */ | |
923f4f23 | 288 | if (pipe->nrbufs && chars != 0) { |
341b446b IM |
289 | int lastbuf = (pipe->curbuf + pipe->nrbufs - 1) & |
290 | (PIPE_BUFFERS-1); | |
923f4f23 | 291 | struct pipe_buffer *buf = pipe->bufs + lastbuf; |
1da177e4 LT |
292 | struct pipe_buf_operations *ops = buf->ops; |
293 | int offset = buf->offset + buf->len; | |
341b446b | 294 | |
1da177e4 | 295 | if (ops->can_merge && offset + chars <= PAGE_SIZE) { |
5274f052 JA |
296 | void *addr; |
297 | int error; | |
298 | ||
923f4f23 | 299 | addr = ops->map(filp, pipe, buf); |
5274f052 JA |
300 | if (IS_ERR(addr)) { |
301 | error = PTR_ERR(addr); | |
302 | goto out; | |
303 | } | |
304 | error = pipe_iov_copy_from_user(offset + addr, iov, | |
305 | chars); | |
923f4f23 | 306 | ops->unmap(pipe, buf); |
1da177e4 LT |
307 | ret = error; |
308 | do_wakeup = 1; | |
309 | if (error) | |
310 | goto out; | |
311 | buf->len += chars; | |
312 | total_len -= chars; | |
313 | ret = chars; | |
314 | if (!total_len) | |
315 | goto out; | |
316 | } | |
317 | } | |
318 | ||
319 | for (;;) { | |
320 | int bufs; | |
341b446b | 321 | |
923f4f23 | 322 | if (!pipe->readers) { |
1da177e4 | 323 | send_sig(SIGPIPE, current, 0); |
341b446b IM |
324 | if (!ret) |
325 | ret = -EPIPE; | |
1da177e4 LT |
326 | break; |
327 | } | |
923f4f23 | 328 | bufs = pipe->nrbufs; |
1da177e4 | 329 | if (bufs < PIPE_BUFFERS) { |
923f4f23 IM |
330 | int newbuf = (pipe->curbuf + bufs) & (PIPE_BUFFERS-1); |
331 | struct pipe_buffer *buf = pipe->bufs + newbuf; | |
332 | struct page *page = pipe->tmp_page; | |
1da177e4 LT |
333 | int error; |
334 | ||
335 | if (!page) { | |
336 | page = alloc_page(GFP_HIGHUSER); | |
337 | if (unlikely(!page)) { | |
338 | ret = ret ? : -ENOMEM; | |
339 | break; | |
340 | } | |
923f4f23 | 341 | pipe->tmp_page = page; |
1da177e4 | 342 | } |
341b446b | 343 | /* Always wake up, even if the copy fails. Otherwise |
1da177e4 LT |
344 | * we lock up (O_NONBLOCK-)readers that sleep due to |
345 | * syscall merging. | |
346 | * FIXME! Is this really true? | |
347 | */ | |
348 | do_wakeup = 1; | |
349 | chars = PAGE_SIZE; | |
350 | if (chars > total_len) | |
351 | chars = total_len; | |
352 | ||
353 | error = pipe_iov_copy_from_user(kmap(page), iov, chars); | |
354 | kunmap(page); | |
355 | if (unlikely(error)) { | |
341b446b IM |
356 | if (!ret) |
357 | ret = -EFAULT; | |
1da177e4 LT |
358 | break; |
359 | } | |
360 | ret += chars; | |
361 | ||
362 | /* Insert it into the buffer array */ | |
363 | buf->page = page; | |
364 | buf->ops = &anon_pipe_buf_ops; | |
365 | buf->offset = 0; | |
366 | buf->len = chars; | |
923f4f23 IM |
367 | pipe->nrbufs = ++bufs; |
368 | pipe->tmp_page = NULL; | |
1da177e4 LT |
369 | |
370 | total_len -= chars; | |
371 | if (!total_len) | |
372 | break; | |
373 | } | |
374 | if (bufs < PIPE_BUFFERS) | |
375 | continue; | |
376 | if (filp->f_flags & O_NONBLOCK) { | |
341b446b IM |
377 | if (!ret) |
378 | ret = -EAGAIN; | |
1da177e4 LT |
379 | break; |
380 | } | |
381 | if (signal_pending(current)) { | |
341b446b IM |
382 | if (!ret) |
383 | ret = -ERESTARTSYS; | |
1da177e4 LT |
384 | break; |
385 | } | |
386 | if (do_wakeup) { | |
923f4f23 IM |
387 | wake_up_interruptible_sync(&pipe->wait); |
388 | kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); | |
1da177e4 LT |
389 | do_wakeup = 0; |
390 | } | |
923f4f23 IM |
391 | pipe->waiting_writers++; |
392 | pipe_wait(pipe); | |
393 | pipe->waiting_writers--; | |
1da177e4 LT |
394 | } |
395 | out: | |
9aeedfc4 | 396 | mutex_unlock(&inode->i_mutex); |
1da177e4 | 397 | if (do_wakeup) { |
923f4f23 IM |
398 | wake_up_interruptible(&pipe->wait); |
399 | kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); | |
1da177e4 LT |
400 | } |
401 | if (ret > 0) | |
870f4817 | 402 | file_update_time(filp); |
1da177e4 LT |
403 | return ret; |
404 | } | |
405 | ||
406 | static ssize_t | |
407 | pipe_write(struct file *filp, const char __user *buf, | |
408 | size_t count, loff_t *ppos) | |
409 | { | |
410 | struct iovec iov = { .iov_base = (void __user *)buf, .iov_len = count }; | |
341b446b | 411 | |
1da177e4 LT |
412 | return pipe_writev(filp, &iov, 1, ppos); |
413 | } | |
414 | ||
415 | static ssize_t | |
416 | bad_pipe_r(struct file *filp, char __user *buf, size_t count, loff_t *ppos) | |
417 | { | |
418 | return -EBADF; | |
419 | } | |
420 | ||
421 | static ssize_t | |
341b446b IM |
422 | bad_pipe_w(struct file *filp, const char __user *buf, size_t count, |
423 | loff_t *ppos) | |
1da177e4 LT |
424 | { |
425 | return -EBADF; | |
426 | } | |
427 | ||
428 | static int | |
429 | pipe_ioctl(struct inode *pino, struct file *filp, | |
430 | unsigned int cmd, unsigned long arg) | |
431 | { | |
432 | struct inode *inode = filp->f_dentry->d_inode; | |
923f4f23 | 433 | struct pipe_inode_info *pipe; |
1da177e4 LT |
434 | int count, buf, nrbufs; |
435 | ||
436 | switch (cmd) { | |
437 | case FIONREAD: | |
9aeedfc4 | 438 | mutex_lock(&inode->i_mutex); |
923f4f23 | 439 | pipe = inode->i_pipe; |
1da177e4 | 440 | count = 0; |
923f4f23 IM |
441 | buf = pipe->curbuf; |
442 | nrbufs = pipe->nrbufs; | |
1da177e4 | 443 | while (--nrbufs >= 0) { |
923f4f23 | 444 | count += pipe->bufs[buf].len; |
1da177e4 LT |
445 | buf = (buf+1) & (PIPE_BUFFERS-1); |
446 | } | |
9aeedfc4 | 447 | mutex_unlock(&inode->i_mutex); |
923f4f23 | 448 | |
1da177e4 LT |
449 | return put_user(count, (int __user *)arg); |
450 | default: | |
451 | return -EINVAL; | |
452 | } | |
453 | } | |
454 | ||
455 | /* No kernel lock held - fine */ | |
456 | static unsigned int | |
457 | pipe_poll(struct file *filp, poll_table *wait) | |
458 | { | |
459 | unsigned int mask; | |
460 | struct inode *inode = filp->f_dentry->d_inode; | |
923f4f23 | 461 | struct pipe_inode_info *pipe = inode->i_pipe; |
1da177e4 LT |
462 | int nrbufs; |
463 | ||
923f4f23 | 464 | poll_wait(filp, &pipe->wait, wait); |
1da177e4 LT |
465 | |
466 | /* Reading only -- no need for acquiring the semaphore. */ | |
923f4f23 | 467 | nrbufs = pipe->nrbufs; |
1da177e4 LT |
468 | mask = 0; |
469 | if (filp->f_mode & FMODE_READ) { | |
470 | mask = (nrbufs > 0) ? POLLIN | POLLRDNORM : 0; | |
923f4f23 | 471 | if (!pipe->writers && filp->f_version != pipe->w_counter) |
1da177e4 LT |
472 | mask |= POLLHUP; |
473 | } | |
474 | ||
475 | if (filp->f_mode & FMODE_WRITE) { | |
476 | mask |= (nrbufs < PIPE_BUFFERS) ? POLLOUT | POLLWRNORM : 0; | |
5e5d7a22 PE |
477 | /* |
478 | * Most Unices do not set POLLERR for FIFOs but on Linux they | |
479 | * behave exactly like pipes for poll(). | |
480 | */ | |
923f4f23 | 481 | if (!pipe->readers) |
1da177e4 LT |
482 | mask |= POLLERR; |
483 | } | |
484 | ||
485 | return mask; | |
486 | } | |
487 | ||
1da177e4 LT |
488 | static int |
489 | pipe_release(struct inode *inode, int decr, int decw) | |
490 | { | |
923f4f23 IM |
491 | struct pipe_inode_info *pipe; |
492 | ||
9aeedfc4 | 493 | mutex_lock(&inode->i_mutex); |
923f4f23 IM |
494 | pipe = inode->i_pipe; |
495 | pipe->readers -= decr; | |
496 | pipe->writers -= decw; | |
341b446b | 497 | |
923f4f23 | 498 | if (!pipe->readers && !pipe->writers) { |
1da177e4 LT |
499 | free_pipe_info(inode); |
500 | } else { | |
923f4f23 IM |
501 | wake_up_interruptible(&pipe->wait); |
502 | kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); | |
503 | kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); | |
1da177e4 | 504 | } |
9aeedfc4 | 505 | mutex_unlock(&inode->i_mutex); |
1da177e4 LT |
506 | |
507 | return 0; | |
508 | } | |
509 | ||
510 | static int | |
511 | pipe_read_fasync(int fd, struct file *filp, int on) | |
512 | { | |
513 | struct inode *inode = filp->f_dentry->d_inode; | |
514 | int retval; | |
515 | ||
9aeedfc4 IM |
516 | mutex_lock(&inode->i_mutex); |
517 | retval = fasync_helper(fd, filp, on, &inode->i_pipe->fasync_readers); | |
518 | mutex_unlock(&inode->i_mutex); | |
1da177e4 LT |
519 | |
520 | if (retval < 0) | |
521 | return retval; | |
522 | ||
523 | return 0; | |
524 | } | |
525 | ||
526 | ||
527 | static int | |
528 | pipe_write_fasync(int fd, struct file *filp, int on) | |
529 | { | |
530 | struct inode *inode = filp->f_dentry->d_inode; | |
531 | int retval; | |
532 | ||
9aeedfc4 IM |
533 | mutex_lock(&inode->i_mutex); |
534 | retval = fasync_helper(fd, filp, on, &inode->i_pipe->fasync_writers); | |
535 | mutex_unlock(&inode->i_mutex); | |
1da177e4 LT |
536 | |
537 | if (retval < 0) | |
538 | return retval; | |
539 | ||
540 | return 0; | |
541 | } | |
542 | ||
543 | ||
544 | static int | |
545 | pipe_rdwr_fasync(int fd, struct file *filp, int on) | |
546 | { | |
547 | struct inode *inode = filp->f_dentry->d_inode; | |
341b446b | 548 | struct pipe_inode_info *pipe = inode->i_pipe; |
1da177e4 LT |
549 | int retval; |
550 | ||
9aeedfc4 | 551 | mutex_lock(&inode->i_mutex); |
1da177e4 | 552 | |
341b446b | 553 | retval = fasync_helper(fd, filp, on, &pipe->fasync_readers); |
1da177e4 LT |
554 | |
555 | if (retval >= 0) | |
341b446b | 556 | retval = fasync_helper(fd, filp, on, &pipe->fasync_writers); |
1da177e4 | 557 | |
9aeedfc4 | 558 | mutex_unlock(&inode->i_mutex); |
1da177e4 LT |
559 | |
560 | if (retval < 0) | |
561 | return retval; | |
562 | ||
563 | return 0; | |
564 | } | |
565 | ||
566 | ||
567 | static int | |
568 | pipe_read_release(struct inode *inode, struct file *filp) | |
569 | { | |
570 | pipe_read_fasync(-1, filp, 0); | |
571 | return pipe_release(inode, 1, 0); | |
572 | } | |
573 | ||
574 | static int | |
575 | pipe_write_release(struct inode *inode, struct file *filp) | |
576 | { | |
577 | pipe_write_fasync(-1, filp, 0); | |
578 | return pipe_release(inode, 0, 1); | |
579 | } | |
580 | ||
581 | static int | |
582 | pipe_rdwr_release(struct inode *inode, struct file *filp) | |
583 | { | |
584 | int decr, decw; | |
585 | ||
586 | pipe_rdwr_fasync(-1, filp, 0); | |
587 | decr = (filp->f_mode & FMODE_READ) != 0; | |
588 | decw = (filp->f_mode & FMODE_WRITE) != 0; | |
589 | return pipe_release(inode, decr, decw); | |
590 | } | |
591 | ||
592 | static int | |
593 | pipe_read_open(struct inode *inode, struct file *filp) | |
594 | { | |
595 | /* We could have perhaps used atomic_t, but this and friends | |
596 | below are the only places. So it doesn't seem worthwhile. */ | |
9aeedfc4 IM |
597 | mutex_lock(&inode->i_mutex); |
598 | inode->i_pipe->readers++; | |
599 | mutex_unlock(&inode->i_mutex); | |
1da177e4 LT |
600 | |
601 | return 0; | |
602 | } | |
603 | ||
604 | static int | |
605 | pipe_write_open(struct inode *inode, struct file *filp) | |
606 | { | |
9aeedfc4 IM |
607 | mutex_lock(&inode->i_mutex); |
608 | inode->i_pipe->writers++; | |
609 | mutex_unlock(&inode->i_mutex); | |
1da177e4 LT |
610 | |
611 | return 0; | |
612 | } | |
613 | ||
614 | static int | |
615 | pipe_rdwr_open(struct inode *inode, struct file *filp) | |
616 | { | |
9aeedfc4 | 617 | mutex_lock(&inode->i_mutex); |
1da177e4 | 618 | if (filp->f_mode & FMODE_READ) |
9aeedfc4 | 619 | inode->i_pipe->readers++; |
1da177e4 | 620 | if (filp->f_mode & FMODE_WRITE) |
9aeedfc4 IM |
621 | inode->i_pipe->writers++; |
622 | mutex_unlock(&inode->i_mutex); | |
1da177e4 LT |
623 | |
624 | return 0; | |
625 | } | |
626 | ||
627 | /* | |
628 | * The file_operations structs are not static because they | |
629 | * are also used in linux/fs/fifo.c to do operations on FIFOs. | |
630 | */ | |
4b6f5d20 | 631 | const struct file_operations read_fifo_fops = { |
1da177e4 LT |
632 | .llseek = no_llseek, |
633 | .read = pipe_read, | |
634 | .readv = pipe_readv, | |
635 | .write = bad_pipe_w, | |
5e5d7a22 | 636 | .poll = pipe_poll, |
1da177e4 LT |
637 | .ioctl = pipe_ioctl, |
638 | .open = pipe_read_open, | |
639 | .release = pipe_read_release, | |
640 | .fasync = pipe_read_fasync, | |
641 | }; | |
642 | ||
4b6f5d20 | 643 | const struct file_operations write_fifo_fops = { |
1da177e4 LT |
644 | .llseek = no_llseek, |
645 | .read = bad_pipe_r, | |
646 | .write = pipe_write, | |
647 | .writev = pipe_writev, | |
5e5d7a22 | 648 | .poll = pipe_poll, |
1da177e4 LT |
649 | .ioctl = pipe_ioctl, |
650 | .open = pipe_write_open, | |
651 | .release = pipe_write_release, | |
652 | .fasync = pipe_write_fasync, | |
653 | }; | |
654 | ||
4b6f5d20 | 655 | const struct file_operations rdwr_fifo_fops = { |
1da177e4 LT |
656 | .llseek = no_llseek, |
657 | .read = pipe_read, | |
658 | .readv = pipe_readv, | |
659 | .write = pipe_write, | |
660 | .writev = pipe_writev, | |
5e5d7a22 | 661 | .poll = pipe_poll, |
1da177e4 LT |
662 | .ioctl = pipe_ioctl, |
663 | .open = pipe_rdwr_open, | |
664 | .release = pipe_rdwr_release, | |
665 | .fasync = pipe_rdwr_fasync, | |
666 | }; | |
667 | ||
a19cbd4b | 668 | static struct file_operations read_pipe_fops = { |
1da177e4 LT |
669 | .llseek = no_llseek, |
670 | .read = pipe_read, | |
671 | .readv = pipe_readv, | |
672 | .write = bad_pipe_w, | |
673 | .poll = pipe_poll, | |
674 | .ioctl = pipe_ioctl, | |
675 | .open = pipe_read_open, | |
676 | .release = pipe_read_release, | |
677 | .fasync = pipe_read_fasync, | |
678 | }; | |
679 | ||
a19cbd4b | 680 | static struct file_operations write_pipe_fops = { |
1da177e4 LT |
681 | .llseek = no_llseek, |
682 | .read = bad_pipe_r, | |
683 | .write = pipe_write, | |
684 | .writev = pipe_writev, | |
685 | .poll = pipe_poll, | |
686 | .ioctl = pipe_ioctl, | |
687 | .open = pipe_write_open, | |
688 | .release = pipe_write_release, | |
689 | .fasync = pipe_write_fasync, | |
690 | }; | |
691 | ||
a19cbd4b | 692 | static struct file_operations rdwr_pipe_fops = { |
1da177e4 LT |
693 | .llseek = no_llseek, |
694 | .read = pipe_read, | |
695 | .readv = pipe_readv, | |
696 | .write = pipe_write, | |
697 | .writev = pipe_writev, | |
698 | .poll = pipe_poll, | |
699 | .ioctl = pipe_ioctl, | |
700 | .open = pipe_rdwr_open, | |
701 | .release = pipe_rdwr_release, | |
702 | .fasync = pipe_rdwr_fasync, | |
703 | }; | |
704 | ||
3a326a2c IM |
705 | struct pipe_inode_info * alloc_pipe_info(struct inode *inode) |
706 | { | |
923f4f23 | 707 | struct pipe_inode_info *pipe; |
3a326a2c | 708 | |
923f4f23 IM |
709 | pipe = kzalloc(sizeof(struct pipe_inode_info), GFP_KERNEL); |
710 | if (pipe) { | |
711 | init_waitqueue_head(&pipe->wait); | |
712 | pipe->r_counter = pipe->w_counter = 1; | |
713 | pipe->inode = inode; | |
3a326a2c IM |
714 | } |
715 | ||
923f4f23 | 716 | return pipe; |
3a326a2c IM |
717 | } |
718 | ||
923f4f23 | 719 | void __free_pipe_info(struct pipe_inode_info *pipe) |
1da177e4 LT |
720 | { |
721 | int i; | |
1da177e4 | 722 | |
1da177e4 | 723 | for (i = 0; i < PIPE_BUFFERS; i++) { |
923f4f23 | 724 | struct pipe_buffer *buf = pipe->bufs + i; |
1da177e4 | 725 | if (buf->ops) |
923f4f23 | 726 | buf->ops->release(pipe, buf); |
1da177e4 | 727 | } |
923f4f23 IM |
728 | if (pipe->tmp_page) |
729 | __free_page(pipe->tmp_page); | |
730 | kfree(pipe); | |
1da177e4 LT |
731 | } |
732 | ||
b92ce558 JA |
733 | void free_pipe_info(struct inode *inode) |
734 | { | |
735 | __free_pipe_info(inode->i_pipe); | |
736 | inode->i_pipe = NULL; | |
737 | } | |
738 | ||
fa3536cc | 739 | static struct vfsmount *pipe_mnt __read_mostly; |
1da177e4 LT |
740 | static int pipefs_delete_dentry(struct dentry *dentry) |
741 | { | |
742 | return 1; | |
743 | } | |
341b446b | 744 | |
1da177e4 LT |
745 | static struct dentry_operations pipefs_dentry_operations = { |
746 | .d_delete = pipefs_delete_dentry, | |
747 | }; | |
748 | ||
749 | static struct inode * get_pipe_inode(void) | |
750 | { | |
751 | struct inode *inode = new_inode(pipe_mnt->mnt_sb); | |
923f4f23 | 752 | struct pipe_inode_info *pipe; |
1da177e4 LT |
753 | |
754 | if (!inode) | |
755 | goto fail_inode; | |
756 | ||
923f4f23 IM |
757 | pipe = alloc_pipe_info(inode); |
758 | if (!pipe) | |
1da177e4 | 759 | goto fail_iput; |
923f4f23 | 760 | inode->i_pipe = pipe; |
3a326a2c | 761 | |
923f4f23 | 762 | pipe->readers = pipe->writers = 1; |
1da177e4 LT |
763 | inode->i_fop = &rdwr_pipe_fops; |
764 | ||
765 | /* | |
766 | * Mark the inode dirty from the very beginning, | |
767 | * that way it will never be moved to the dirty | |
768 | * list because "mark_inode_dirty()" will think | |
769 | * that it already _is_ on the dirty list. | |
770 | */ | |
771 | inode->i_state = I_DIRTY; | |
772 | inode->i_mode = S_IFIFO | S_IRUSR | S_IWUSR; | |
773 | inode->i_uid = current->fsuid; | |
774 | inode->i_gid = current->fsgid; | |
775 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; | |
776 | inode->i_blksize = PAGE_SIZE; | |
923f4f23 | 777 | |
1da177e4 LT |
778 | return inode; |
779 | ||
780 | fail_iput: | |
781 | iput(inode); | |
341b446b | 782 | |
1da177e4 LT |
783 | fail_inode: |
784 | return NULL; | |
785 | } | |
786 | ||
787 | int do_pipe(int *fd) | |
788 | { | |
789 | struct qstr this; | |
790 | char name[32]; | |
791 | struct dentry *dentry; | |
792 | struct inode * inode; | |
793 | struct file *f1, *f2; | |
794 | int error; | |
341b446b | 795 | int i, j; |
1da177e4 LT |
796 | |
797 | error = -ENFILE; | |
798 | f1 = get_empty_filp(); | |
799 | if (!f1) | |
800 | goto no_files; | |
801 | ||
802 | f2 = get_empty_filp(); | |
803 | if (!f2) | |
804 | goto close_f1; | |
805 | ||
806 | inode = get_pipe_inode(); | |
807 | if (!inode) | |
808 | goto close_f12; | |
809 | ||
810 | error = get_unused_fd(); | |
811 | if (error < 0) | |
812 | goto close_f12_inode; | |
813 | i = error; | |
814 | ||
815 | error = get_unused_fd(); | |
816 | if (error < 0) | |
817 | goto close_f12_inode_i; | |
818 | j = error; | |
819 | ||
820 | error = -ENOMEM; | |
821 | sprintf(name, "[%lu]", inode->i_ino); | |
822 | this.name = name; | |
823 | this.len = strlen(name); | |
824 | this.hash = inode->i_ino; /* will go */ | |
825 | dentry = d_alloc(pipe_mnt->mnt_sb->s_root, &this); | |
826 | if (!dentry) | |
827 | goto close_f12_inode_i_j; | |
341b446b | 828 | |
1da177e4 LT |
829 | dentry->d_op = &pipefs_dentry_operations; |
830 | d_add(dentry, inode); | |
831 | f1->f_vfsmnt = f2->f_vfsmnt = mntget(mntget(pipe_mnt)); | |
832 | f1->f_dentry = f2->f_dentry = dget(dentry); | |
833 | f1->f_mapping = f2->f_mapping = inode->i_mapping; | |
834 | ||
835 | /* read file */ | |
836 | f1->f_pos = f2->f_pos = 0; | |
837 | f1->f_flags = O_RDONLY; | |
838 | f1->f_op = &read_pipe_fops; | |
839 | f1->f_mode = FMODE_READ; | |
840 | f1->f_version = 0; | |
841 | ||
842 | /* write file */ | |
843 | f2->f_flags = O_WRONLY; | |
844 | f2->f_op = &write_pipe_fops; | |
845 | f2->f_mode = FMODE_WRITE; | |
846 | f2->f_version = 0; | |
847 | ||
848 | fd_install(i, f1); | |
849 | fd_install(j, f2); | |
850 | fd[0] = i; | |
851 | fd[1] = j; | |
341b446b | 852 | |
1da177e4 LT |
853 | return 0; |
854 | ||
855 | close_f12_inode_i_j: | |
856 | put_unused_fd(j); | |
857 | close_f12_inode_i: | |
858 | put_unused_fd(i); | |
859 | close_f12_inode: | |
860 | free_pipe_info(inode); | |
861 | iput(inode); | |
862 | close_f12: | |
863 | put_filp(f2); | |
864 | close_f1: | |
865 | put_filp(f1); | |
866 | no_files: | |
867 | return error; | |
868 | } | |
869 | ||
870 | /* | |
871 | * pipefs should _never_ be mounted by userland - too much of security hassle, | |
872 | * no real gain from having the whole whorehouse mounted. So we don't need | |
873 | * any operations on the root directory. However, we need a non-trivial | |
874 | * d_name - pipe: will go nicely and kill the special-casing in procfs. | |
875 | */ | |
876 | ||
341b446b IM |
877 | static struct super_block * |
878 | pipefs_get_sb(struct file_system_type *fs_type, int flags, | |
879 | const char *dev_name, void *data) | |
1da177e4 LT |
880 | { |
881 | return get_sb_pseudo(fs_type, "pipe:", NULL, PIPEFS_MAGIC); | |
882 | } | |
883 | ||
884 | static struct file_system_type pipe_fs_type = { | |
885 | .name = "pipefs", | |
886 | .get_sb = pipefs_get_sb, | |
887 | .kill_sb = kill_anon_super, | |
888 | }; | |
889 | ||
890 | static int __init init_pipe_fs(void) | |
891 | { | |
892 | int err = register_filesystem(&pipe_fs_type); | |
341b446b | 893 | |
1da177e4 LT |
894 | if (!err) { |
895 | pipe_mnt = kern_mount(&pipe_fs_type); | |
896 | if (IS_ERR(pipe_mnt)) { | |
897 | err = PTR_ERR(pipe_mnt); | |
898 | unregister_filesystem(&pipe_fs_type); | |
899 | } | |
900 | } | |
901 | return err; | |
902 | } | |
903 | ||
904 | static void __exit exit_pipe_fs(void) | |
905 | { | |
906 | unregister_filesystem(&pipe_fs_type); | |
907 | mntput(pipe_mnt); | |
908 | } | |
909 | ||
910 | fs_initcall(init_pipe_fs); | |
911 | module_exit(exit_pipe_fs); |