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