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> | |
35f3d14d | 14 | #include <linux/log2.h> |
1da177e4 | 15 | #include <linux/mount.h> |
b502bd11 | 16 | #include <linux/magic.h> |
1da177e4 LT |
17 | #include <linux/pipe_fs_i.h> |
18 | #include <linux/uio.h> | |
19 | #include <linux/highmem.h> | |
5274f052 | 20 | #include <linux/pagemap.h> |
db349509 | 21 | #include <linux/audit.h> |
ba719bae | 22 | #include <linux/syscalls.h> |
b492e95b | 23 | #include <linux/fcntl.h> |
a27bb332 | 24 | #include <linux/aio.h> |
1da177e4 LT |
25 | |
26 | #include <asm/uaccess.h> | |
27 | #include <asm/ioctls.h> | |
28 | ||
599a0ac1 AV |
29 | #include "internal.h" |
30 | ||
b492e95b JA |
31 | /* |
32 | * The max size that a non-root user is allowed to grow the pipe. Can | |
ff9da691 | 33 | * be set by root in /proc/sys/fs/pipe-max-size |
b492e95b | 34 | */ |
ff9da691 JA |
35 | unsigned int pipe_max_size = 1048576; |
36 | ||
37 | /* | |
38 | * Minimum pipe size, as required by POSIX | |
39 | */ | |
40 | unsigned int pipe_min_size = PAGE_SIZE; | |
b492e95b | 41 | |
1da177e4 LT |
42 | /* |
43 | * We use a start+len construction, which provides full use of the | |
44 | * allocated memory. | |
45 | * -- Florian Coosmann (FGC) | |
46 | * | |
47 | * Reads with count = 0 should always return 0. | |
48 | * -- Julian Bradfield 1999-06-07. | |
49 | * | |
50 | * FIFOs and Pipes now generate SIGIO for both readers and writers. | |
51 | * -- Jeremy Elson <jelson@circlemud.org> 2001-08-16 | |
52 | * | |
53 | * pipe_read & write cleanup | |
54 | * -- Manfred Spraul <manfred@colorfullife.com> 2002-05-09 | |
55 | */ | |
56 | ||
61e0d47c MS |
57 | static void pipe_lock_nested(struct pipe_inode_info *pipe, int subclass) |
58 | { | |
6447a3cf | 59 | if (pipe->files) |
72b0d9aa | 60 | mutex_lock_nested(&pipe->mutex, subclass); |
61e0d47c MS |
61 | } |
62 | ||
63 | void pipe_lock(struct pipe_inode_info *pipe) | |
64 | { | |
65 | /* | |
66 | * pipe_lock() nests non-pipe inode locks (for writing to a file) | |
67 | */ | |
68 | pipe_lock_nested(pipe, I_MUTEX_PARENT); | |
69 | } | |
70 | EXPORT_SYMBOL(pipe_lock); | |
71 | ||
72 | void pipe_unlock(struct pipe_inode_info *pipe) | |
73 | { | |
6447a3cf | 74 | if (pipe->files) |
72b0d9aa | 75 | mutex_unlock(&pipe->mutex); |
61e0d47c MS |
76 | } |
77 | EXPORT_SYMBOL(pipe_unlock); | |
78 | ||
ebec73f4 AV |
79 | static inline void __pipe_lock(struct pipe_inode_info *pipe) |
80 | { | |
81 | mutex_lock_nested(&pipe->mutex, I_MUTEX_PARENT); | |
82 | } | |
83 | ||
84 | static inline void __pipe_unlock(struct pipe_inode_info *pipe) | |
85 | { | |
86 | mutex_unlock(&pipe->mutex); | |
87 | } | |
88 | ||
61e0d47c MS |
89 | void pipe_double_lock(struct pipe_inode_info *pipe1, |
90 | struct pipe_inode_info *pipe2) | |
91 | { | |
92 | BUG_ON(pipe1 == pipe2); | |
93 | ||
94 | if (pipe1 < pipe2) { | |
95 | pipe_lock_nested(pipe1, I_MUTEX_PARENT); | |
96 | pipe_lock_nested(pipe2, I_MUTEX_CHILD); | |
97 | } else { | |
023d43c7 PZ |
98 | pipe_lock_nested(pipe2, I_MUTEX_PARENT); |
99 | pipe_lock_nested(pipe1, I_MUTEX_CHILD); | |
61e0d47c MS |
100 | } |
101 | } | |
102 | ||
1da177e4 | 103 | /* Drop the inode semaphore and wait for a pipe event, atomically */ |
3a326a2c | 104 | void pipe_wait(struct pipe_inode_info *pipe) |
1da177e4 LT |
105 | { |
106 | DEFINE_WAIT(wait); | |
107 | ||
d79fc0fc IM |
108 | /* |
109 | * Pipes are system-local resources, so sleeping on them | |
110 | * is considered a noninteractive wait: | |
111 | */ | |
af927232 | 112 | prepare_to_wait(&pipe->wait, &wait, TASK_INTERRUPTIBLE); |
61e0d47c | 113 | pipe_unlock(pipe); |
1da177e4 | 114 | schedule(); |
3a326a2c | 115 | finish_wait(&pipe->wait, &wait); |
61e0d47c | 116 | pipe_lock(pipe); |
1da177e4 LT |
117 | } |
118 | ||
858119e1 | 119 | static int |
f6762b7a JA |
120 | pipe_iov_copy_from_user(void *to, struct iovec *iov, unsigned long len, |
121 | int atomic) | |
1da177e4 LT |
122 | { |
123 | unsigned long copy; | |
124 | ||
125 | while (len > 0) { | |
126 | while (!iov->iov_len) | |
127 | iov++; | |
128 | copy = min_t(unsigned long, len, iov->iov_len); | |
129 | ||
f6762b7a JA |
130 | if (atomic) { |
131 | if (__copy_from_user_inatomic(to, iov->iov_base, copy)) | |
132 | return -EFAULT; | |
133 | } else { | |
134 | if (copy_from_user(to, iov->iov_base, copy)) | |
135 | return -EFAULT; | |
136 | } | |
1da177e4 LT |
137 | to += copy; |
138 | len -= copy; | |
139 | iov->iov_base += copy; | |
140 | iov->iov_len -= copy; | |
141 | } | |
142 | return 0; | |
143 | } | |
144 | ||
858119e1 | 145 | static int |
f6762b7a JA |
146 | pipe_iov_copy_to_user(struct iovec *iov, const void *from, unsigned long len, |
147 | int atomic) | |
1da177e4 LT |
148 | { |
149 | unsigned long copy; | |
150 | ||
151 | while (len > 0) { | |
152 | while (!iov->iov_len) | |
153 | iov++; | |
154 | copy = min_t(unsigned long, len, iov->iov_len); | |
155 | ||
f6762b7a JA |
156 | if (atomic) { |
157 | if (__copy_to_user_inatomic(iov->iov_base, from, copy)) | |
158 | return -EFAULT; | |
159 | } else { | |
160 | if (copy_to_user(iov->iov_base, from, copy)) | |
161 | return -EFAULT; | |
162 | } | |
1da177e4 LT |
163 | from += copy; |
164 | len -= copy; | |
165 | iov->iov_base += copy; | |
166 | iov->iov_len -= copy; | |
167 | } | |
168 | return 0; | |
169 | } | |
170 | ||
f6762b7a JA |
171 | /* |
172 | * Attempt to pre-fault in the user memory, so we can use atomic copies. | |
173 | * Returns the number of bytes not faulted in. | |
174 | */ | |
175 | static int iov_fault_in_pages_write(struct iovec *iov, unsigned long len) | |
176 | { | |
177 | while (!iov->iov_len) | |
178 | iov++; | |
179 | ||
180 | while (len > 0) { | |
181 | unsigned long this_len; | |
182 | ||
183 | this_len = min_t(unsigned long, len, iov->iov_len); | |
184 | if (fault_in_pages_writeable(iov->iov_base, this_len)) | |
185 | break; | |
186 | ||
187 | len -= this_len; | |
188 | iov++; | |
189 | } | |
190 | ||
191 | return len; | |
192 | } | |
193 | ||
194 | /* | |
195 | * Pre-fault in the user memory, so we can use atomic copies. | |
196 | */ | |
197 | static void iov_fault_in_pages_read(struct iovec *iov, unsigned long len) | |
198 | { | |
199 | while (!iov->iov_len) | |
200 | iov++; | |
201 | ||
202 | while (len > 0) { | |
203 | unsigned long this_len; | |
204 | ||
205 | this_len = min_t(unsigned long, len, iov->iov_len); | |
206 | fault_in_pages_readable(iov->iov_base, this_len); | |
207 | len -= this_len; | |
208 | iov++; | |
209 | } | |
210 | } | |
211 | ||
341b446b IM |
212 | static void anon_pipe_buf_release(struct pipe_inode_info *pipe, |
213 | struct pipe_buffer *buf) | |
1da177e4 LT |
214 | { |
215 | struct page *page = buf->page; | |
216 | ||
5274f052 JA |
217 | /* |
218 | * If nobody else uses this page, and we don't already have a | |
219 | * temporary page, let's keep track of it as a one-deep | |
341b446b | 220 | * allocation cache. (Otherwise just release our reference to it) |
5274f052 | 221 | */ |
341b446b | 222 | if (page_count(page) == 1 && !pipe->tmp_page) |
923f4f23 | 223 | pipe->tmp_page = page; |
341b446b IM |
224 | else |
225 | page_cache_release(page); | |
1da177e4 LT |
226 | } |
227 | ||
0845718d | 228 | /** |
b51d63c6 | 229 | * generic_pipe_buf_steal - attempt to take ownership of a &pipe_buffer |
0845718d JA |
230 | * @pipe: the pipe that the buffer belongs to |
231 | * @buf: the buffer to attempt to steal | |
232 | * | |
233 | * Description: | |
b51d63c6 | 234 | * This function attempts to steal the &struct page attached to |
0845718d JA |
235 | * @buf. If successful, this function returns 0 and returns with |
236 | * the page locked. The caller may then reuse the page for whatever | |
b51d63c6 | 237 | * he wishes; the typical use is insertion into a different file |
0845718d JA |
238 | * page cache. |
239 | */ | |
330ab716 JA |
240 | int generic_pipe_buf_steal(struct pipe_inode_info *pipe, |
241 | struct pipe_buffer *buf) | |
5abc97aa | 242 | { |
46e678c9 JA |
243 | struct page *page = buf->page; |
244 | ||
0845718d JA |
245 | /* |
246 | * A reference of one is golden, that means that the owner of this | |
247 | * page is the only one holding a reference to it. lock the page | |
248 | * and return OK. | |
249 | */ | |
46e678c9 | 250 | if (page_count(page) == 1) { |
46e678c9 JA |
251 | lock_page(page); |
252 | return 0; | |
253 | } | |
254 | ||
255 | return 1; | |
5abc97aa | 256 | } |
51921cb7 | 257 | EXPORT_SYMBOL(generic_pipe_buf_steal); |
5abc97aa | 258 | |
0845718d | 259 | /** |
b51d63c6 | 260 | * generic_pipe_buf_get - get a reference to a &struct pipe_buffer |
0845718d JA |
261 | * @pipe: the pipe that the buffer belongs to |
262 | * @buf: the buffer to get a reference to | |
263 | * | |
264 | * Description: | |
265 | * This function grabs an extra reference to @buf. It's used in | |
266 | * in the tee() system call, when we duplicate the buffers in one | |
267 | * pipe into another. | |
268 | */ | |
269 | void generic_pipe_buf_get(struct pipe_inode_info *pipe, struct pipe_buffer *buf) | |
70524490 JA |
270 | { |
271 | page_cache_get(buf->page); | |
272 | } | |
51921cb7 | 273 | EXPORT_SYMBOL(generic_pipe_buf_get); |
70524490 | 274 | |
0845718d JA |
275 | /** |
276 | * generic_pipe_buf_confirm - verify contents of the pipe buffer | |
79685b8d | 277 | * @info: the pipe that the buffer belongs to |
0845718d JA |
278 | * @buf: the buffer to confirm |
279 | * | |
280 | * Description: | |
281 | * This function does nothing, because the generic pipe code uses | |
282 | * pages that are always good when inserted into the pipe. | |
283 | */ | |
cac36bb0 JA |
284 | int generic_pipe_buf_confirm(struct pipe_inode_info *info, |
285 | struct pipe_buffer *buf) | |
f84d7519 JA |
286 | { |
287 | return 0; | |
288 | } | |
51921cb7 | 289 | EXPORT_SYMBOL(generic_pipe_buf_confirm); |
f84d7519 | 290 | |
6818173b MS |
291 | /** |
292 | * generic_pipe_buf_release - put a reference to a &struct pipe_buffer | |
293 | * @pipe: the pipe that the buffer belongs to | |
294 | * @buf: the buffer to put a reference to | |
295 | * | |
296 | * Description: | |
297 | * This function releases a reference to @buf. | |
298 | */ | |
299 | void generic_pipe_buf_release(struct pipe_inode_info *pipe, | |
300 | struct pipe_buffer *buf) | |
301 | { | |
302 | page_cache_release(buf->page); | |
303 | } | |
51921cb7 | 304 | EXPORT_SYMBOL(generic_pipe_buf_release); |
6818173b | 305 | |
d4c3cca9 | 306 | static const struct pipe_buf_operations anon_pipe_buf_ops = { |
1da177e4 | 307 | .can_merge = 1, |
cac36bb0 | 308 | .confirm = generic_pipe_buf_confirm, |
1da177e4 | 309 | .release = anon_pipe_buf_release, |
330ab716 | 310 | .steal = generic_pipe_buf_steal, |
f84d7519 | 311 | .get = generic_pipe_buf_get, |
1da177e4 LT |
312 | }; |
313 | ||
9883035a LT |
314 | static const struct pipe_buf_operations packet_pipe_buf_ops = { |
315 | .can_merge = 0, | |
9883035a LT |
316 | .confirm = generic_pipe_buf_confirm, |
317 | .release = anon_pipe_buf_release, | |
318 | .steal = generic_pipe_buf_steal, | |
319 | .get = generic_pipe_buf_get, | |
320 | }; | |
321 | ||
1da177e4 | 322 | static ssize_t |
ee0b3e67 BP |
323 | pipe_read(struct kiocb *iocb, const struct iovec *_iov, |
324 | unsigned long nr_segs, loff_t pos) | |
1da177e4 | 325 | { |
ee0b3e67 | 326 | struct file *filp = iocb->ki_filp; |
de32ec4c | 327 | struct pipe_inode_info *pipe = filp->private_data; |
1da177e4 LT |
328 | int do_wakeup; |
329 | ssize_t ret; | |
330 | struct iovec *iov = (struct iovec *)_iov; | |
331 | size_t total_len; | |
332 | ||
333 | total_len = iov_length(iov, nr_segs); | |
334 | /* Null read succeeds. */ | |
335 | if (unlikely(total_len == 0)) | |
336 | return 0; | |
337 | ||
338 | do_wakeup = 0; | |
339 | ret = 0; | |
ebec73f4 | 340 | __pipe_lock(pipe); |
1da177e4 | 341 | for (;;) { |
923f4f23 | 342 | int bufs = pipe->nrbufs; |
1da177e4 | 343 | if (bufs) { |
923f4f23 IM |
344 | int curbuf = pipe->curbuf; |
345 | struct pipe_buffer *buf = pipe->bufs + curbuf; | |
d4c3cca9 | 346 | const struct pipe_buf_operations *ops = buf->ops; |
1da177e4 LT |
347 | void *addr; |
348 | size_t chars = buf->len; | |
f6762b7a | 349 | int error, atomic; |
1da177e4 LT |
350 | |
351 | if (chars > total_len) | |
352 | chars = total_len; | |
353 | ||
cac36bb0 | 354 | error = ops->confirm(pipe, buf); |
f84d7519 | 355 | if (error) { |
5274f052 | 356 | if (!ret) |
e5953cbd | 357 | ret = error; |
5274f052 JA |
358 | break; |
359 | } | |
f84d7519 | 360 | |
f6762b7a JA |
361 | atomic = !iov_fault_in_pages_write(iov, chars); |
362 | redo: | |
fbb32750 AV |
363 | if (atomic) |
364 | addr = kmap_atomic(buf->page); | |
365 | else | |
366 | addr = kmap(buf->page); | |
f6762b7a | 367 | error = pipe_iov_copy_to_user(iov, addr + buf->offset, chars, atomic); |
fbb32750 AV |
368 | if (atomic) |
369 | kunmap_atomic(addr); | |
370 | else | |
371 | kunmap(buf->page); | |
1da177e4 | 372 | if (unlikely(error)) { |
f6762b7a JA |
373 | /* |
374 | * Just retry with the slow path if we failed. | |
375 | */ | |
376 | if (atomic) { | |
377 | atomic = 0; | |
378 | goto redo; | |
379 | } | |
341b446b | 380 | if (!ret) |
f6762b7a | 381 | ret = error; |
1da177e4 LT |
382 | break; |
383 | } | |
384 | ret += chars; | |
385 | buf->offset += chars; | |
386 | buf->len -= chars; | |
9883035a LT |
387 | |
388 | /* Was it a packet buffer? Clean up and exit */ | |
389 | if (buf->flags & PIPE_BUF_FLAG_PACKET) { | |
390 | total_len = chars; | |
391 | buf->len = 0; | |
392 | } | |
393 | ||
1da177e4 LT |
394 | if (!buf->len) { |
395 | buf->ops = NULL; | |
923f4f23 | 396 | ops->release(pipe, buf); |
35f3d14d | 397 | curbuf = (curbuf + 1) & (pipe->buffers - 1); |
923f4f23 IM |
398 | pipe->curbuf = curbuf; |
399 | pipe->nrbufs = --bufs; | |
1da177e4 LT |
400 | do_wakeup = 1; |
401 | } | |
402 | total_len -= chars; | |
403 | if (!total_len) | |
404 | break; /* common path: read succeeded */ | |
405 | } | |
406 | if (bufs) /* More to do? */ | |
407 | continue; | |
923f4f23 | 408 | if (!pipe->writers) |
1da177e4 | 409 | break; |
923f4f23 | 410 | if (!pipe->waiting_writers) { |
1da177e4 LT |
411 | /* syscall merging: Usually we must not sleep |
412 | * if O_NONBLOCK is set, or if we got some data. | |
413 | * But if a writer sleeps in kernel space, then | |
414 | * we can wait for that data without violating POSIX. | |
415 | */ | |
416 | if (ret) | |
417 | break; | |
418 | if (filp->f_flags & O_NONBLOCK) { | |
419 | ret = -EAGAIN; | |
420 | break; | |
421 | } | |
422 | } | |
423 | if (signal_pending(current)) { | |
341b446b IM |
424 | if (!ret) |
425 | ret = -ERESTARTSYS; | |
1da177e4 LT |
426 | break; |
427 | } | |
428 | if (do_wakeup) { | |
28e58ee8 | 429 | wake_up_interruptible_sync_poll(&pipe->wait, POLLOUT | POLLWRNORM); |
923f4f23 | 430 | kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); |
1da177e4 | 431 | } |
923f4f23 | 432 | pipe_wait(pipe); |
1da177e4 | 433 | } |
ebec73f4 | 434 | __pipe_unlock(pipe); |
341b446b IM |
435 | |
436 | /* Signal writers asynchronously that there is more room. */ | |
1da177e4 | 437 | if (do_wakeup) { |
28e58ee8 | 438 | wake_up_interruptible_sync_poll(&pipe->wait, POLLOUT | POLLWRNORM); |
923f4f23 | 439 | kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); |
1da177e4 LT |
440 | } |
441 | if (ret > 0) | |
442 | file_accessed(filp); | |
443 | return ret; | |
444 | } | |
445 | ||
9883035a LT |
446 | static inline int is_packetized(struct file *file) |
447 | { | |
448 | return (file->f_flags & O_DIRECT) != 0; | |
449 | } | |
450 | ||
1da177e4 | 451 | static ssize_t |
ee0b3e67 BP |
452 | pipe_write(struct kiocb *iocb, const struct iovec *_iov, |
453 | unsigned long nr_segs, loff_t ppos) | |
1da177e4 | 454 | { |
ee0b3e67 | 455 | struct file *filp = iocb->ki_filp; |
de32ec4c | 456 | struct pipe_inode_info *pipe = filp->private_data; |
1da177e4 LT |
457 | ssize_t ret; |
458 | int do_wakeup; | |
459 | struct iovec *iov = (struct iovec *)_iov; | |
460 | size_t total_len; | |
461 | ssize_t chars; | |
462 | ||
463 | total_len = iov_length(iov, nr_segs); | |
464 | /* Null write succeeds. */ | |
465 | if (unlikely(total_len == 0)) | |
466 | return 0; | |
467 | ||
468 | do_wakeup = 0; | |
469 | ret = 0; | |
ebec73f4 | 470 | __pipe_lock(pipe); |
1da177e4 | 471 | |
923f4f23 | 472 | if (!pipe->readers) { |
1da177e4 LT |
473 | send_sig(SIGPIPE, current, 0); |
474 | ret = -EPIPE; | |
475 | goto out; | |
476 | } | |
477 | ||
478 | /* We try to merge small writes */ | |
479 | chars = total_len & (PAGE_SIZE-1); /* size of the last buffer */ | |
923f4f23 | 480 | if (pipe->nrbufs && chars != 0) { |
341b446b | 481 | int lastbuf = (pipe->curbuf + pipe->nrbufs - 1) & |
35f3d14d | 482 | (pipe->buffers - 1); |
923f4f23 | 483 | struct pipe_buffer *buf = pipe->bufs + lastbuf; |
d4c3cca9 | 484 | const struct pipe_buf_operations *ops = buf->ops; |
1da177e4 | 485 | int offset = buf->offset + buf->len; |
341b446b | 486 | |
1da177e4 | 487 | if (ops->can_merge && offset + chars <= PAGE_SIZE) { |
f6762b7a | 488 | int error, atomic = 1; |
5274f052 | 489 | void *addr; |
5274f052 | 490 | |
cac36bb0 | 491 | error = ops->confirm(pipe, buf); |
f84d7519 | 492 | if (error) |
5274f052 | 493 | goto out; |
f84d7519 | 494 | |
f6762b7a JA |
495 | iov_fault_in_pages_read(iov, chars); |
496 | redo1: | |
fbb32750 AV |
497 | if (atomic) |
498 | addr = kmap_atomic(buf->page); | |
499 | else | |
500 | addr = kmap(buf->page); | |
5274f052 | 501 | error = pipe_iov_copy_from_user(offset + addr, iov, |
f6762b7a | 502 | chars, atomic); |
fbb32750 AV |
503 | if (atomic) |
504 | kunmap_atomic(addr); | |
505 | else | |
506 | kunmap(buf->page); | |
1da177e4 LT |
507 | ret = error; |
508 | do_wakeup = 1; | |
f6762b7a JA |
509 | if (error) { |
510 | if (atomic) { | |
511 | atomic = 0; | |
512 | goto redo1; | |
513 | } | |
1da177e4 | 514 | goto out; |
f6762b7a | 515 | } |
1da177e4 LT |
516 | buf->len += chars; |
517 | total_len -= chars; | |
518 | ret = chars; | |
519 | if (!total_len) | |
520 | goto out; | |
521 | } | |
522 | } | |
523 | ||
524 | for (;;) { | |
525 | int bufs; | |
341b446b | 526 | |
923f4f23 | 527 | if (!pipe->readers) { |
1da177e4 | 528 | send_sig(SIGPIPE, current, 0); |
341b446b IM |
529 | if (!ret) |
530 | ret = -EPIPE; | |
1da177e4 LT |
531 | break; |
532 | } | |
923f4f23 | 533 | bufs = pipe->nrbufs; |
35f3d14d JA |
534 | if (bufs < pipe->buffers) { |
535 | int newbuf = (pipe->curbuf + bufs) & (pipe->buffers-1); | |
923f4f23 IM |
536 | struct pipe_buffer *buf = pipe->bufs + newbuf; |
537 | struct page *page = pipe->tmp_page; | |
f6762b7a JA |
538 | char *src; |
539 | int error, atomic = 1; | |
1da177e4 LT |
540 | |
541 | if (!page) { | |
542 | page = alloc_page(GFP_HIGHUSER); | |
543 | if (unlikely(!page)) { | |
544 | ret = ret ? : -ENOMEM; | |
545 | break; | |
546 | } | |
923f4f23 | 547 | pipe->tmp_page = page; |
1da177e4 | 548 | } |
341b446b | 549 | /* Always wake up, even if the copy fails. Otherwise |
1da177e4 LT |
550 | * we lock up (O_NONBLOCK-)readers that sleep due to |
551 | * syscall merging. | |
552 | * FIXME! Is this really true? | |
553 | */ | |
554 | do_wakeup = 1; | |
555 | chars = PAGE_SIZE; | |
556 | if (chars > total_len) | |
557 | chars = total_len; | |
558 | ||
f6762b7a JA |
559 | iov_fault_in_pages_read(iov, chars); |
560 | redo2: | |
561 | if (atomic) | |
e8e3c3d6 | 562 | src = kmap_atomic(page); |
f6762b7a JA |
563 | else |
564 | src = kmap(page); | |
565 | ||
566 | error = pipe_iov_copy_from_user(src, iov, chars, | |
567 | atomic); | |
568 | if (atomic) | |
e8e3c3d6 | 569 | kunmap_atomic(src); |
f6762b7a JA |
570 | else |
571 | kunmap(page); | |
572 | ||
1da177e4 | 573 | if (unlikely(error)) { |
f6762b7a JA |
574 | if (atomic) { |
575 | atomic = 0; | |
576 | goto redo2; | |
577 | } | |
341b446b | 578 | if (!ret) |
f6762b7a | 579 | ret = error; |
1da177e4 LT |
580 | break; |
581 | } | |
582 | ret += chars; | |
583 | ||
584 | /* Insert it into the buffer array */ | |
585 | buf->page = page; | |
586 | buf->ops = &anon_pipe_buf_ops; | |
587 | buf->offset = 0; | |
588 | buf->len = chars; | |
9883035a LT |
589 | buf->flags = 0; |
590 | if (is_packetized(filp)) { | |
591 | buf->ops = &packet_pipe_buf_ops; | |
592 | buf->flags = PIPE_BUF_FLAG_PACKET; | |
593 | } | |
923f4f23 IM |
594 | pipe->nrbufs = ++bufs; |
595 | pipe->tmp_page = NULL; | |
1da177e4 LT |
596 | |
597 | total_len -= chars; | |
598 | if (!total_len) | |
599 | break; | |
600 | } | |
35f3d14d | 601 | if (bufs < pipe->buffers) |
1da177e4 LT |
602 | continue; |
603 | if (filp->f_flags & O_NONBLOCK) { | |
341b446b IM |
604 | if (!ret) |
605 | ret = -EAGAIN; | |
1da177e4 LT |
606 | break; |
607 | } | |
608 | if (signal_pending(current)) { | |
341b446b IM |
609 | if (!ret) |
610 | ret = -ERESTARTSYS; | |
1da177e4 LT |
611 | break; |
612 | } | |
613 | if (do_wakeup) { | |
28e58ee8 | 614 | wake_up_interruptible_sync_poll(&pipe->wait, POLLIN | POLLRDNORM); |
923f4f23 | 615 | kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); |
1da177e4 LT |
616 | do_wakeup = 0; |
617 | } | |
923f4f23 IM |
618 | pipe->waiting_writers++; |
619 | pipe_wait(pipe); | |
620 | pipe->waiting_writers--; | |
1da177e4 LT |
621 | } |
622 | out: | |
ebec73f4 | 623 | __pipe_unlock(pipe); |
1da177e4 | 624 | if (do_wakeup) { |
28e58ee8 | 625 | wake_up_interruptible_sync_poll(&pipe->wait, POLLIN | POLLRDNORM); |
923f4f23 | 626 | kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); |
1da177e4 | 627 | } |
7e775f46 | 628 | if (ret > 0 && sb_start_write_trylock(file_inode(filp)->i_sb)) { |
c3b2da31 JB |
629 | int err = file_update_time(filp); |
630 | if (err) | |
631 | ret = err; | |
7e775f46 | 632 | sb_end_write(file_inode(filp)->i_sb); |
c3b2da31 | 633 | } |
1da177e4 LT |
634 | return ret; |
635 | } | |
636 | ||
d59d0b1b | 637 | static long pipe_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) |
1da177e4 | 638 | { |
de32ec4c | 639 | struct pipe_inode_info *pipe = filp->private_data; |
1da177e4 LT |
640 | int count, buf, nrbufs; |
641 | ||
642 | switch (cmd) { | |
643 | case FIONREAD: | |
ebec73f4 | 644 | __pipe_lock(pipe); |
1da177e4 | 645 | count = 0; |
923f4f23 IM |
646 | buf = pipe->curbuf; |
647 | nrbufs = pipe->nrbufs; | |
1da177e4 | 648 | while (--nrbufs >= 0) { |
923f4f23 | 649 | count += pipe->bufs[buf].len; |
35f3d14d | 650 | buf = (buf+1) & (pipe->buffers - 1); |
1da177e4 | 651 | } |
ebec73f4 | 652 | __pipe_unlock(pipe); |
923f4f23 | 653 | |
1da177e4 LT |
654 | return put_user(count, (int __user *)arg); |
655 | default: | |
46ce341b | 656 | return -ENOIOCTLCMD; |
1da177e4 LT |
657 | } |
658 | } | |
659 | ||
660 | /* No kernel lock held - fine */ | |
661 | static unsigned int | |
662 | pipe_poll(struct file *filp, poll_table *wait) | |
663 | { | |
664 | unsigned int mask; | |
de32ec4c | 665 | struct pipe_inode_info *pipe = filp->private_data; |
1da177e4 LT |
666 | int nrbufs; |
667 | ||
923f4f23 | 668 | poll_wait(filp, &pipe->wait, wait); |
1da177e4 LT |
669 | |
670 | /* Reading only -- no need for acquiring the semaphore. */ | |
923f4f23 | 671 | nrbufs = pipe->nrbufs; |
1da177e4 LT |
672 | mask = 0; |
673 | if (filp->f_mode & FMODE_READ) { | |
674 | mask = (nrbufs > 0) ? POLLIN | POLLRDNORM : 0; | |
923f4f23 | 675 | if (!pipe->writers && filp->f_version != pipe->w_counter) |
1da177e4 LT |
676 | mask |= POLLHUP; |
677 | } | |
678 | ||
679 | if (filp->f_mode & FMODE_WRITE) { | |
35f3d14d | 680 | mask |= (nrbufs < pipe->buffers) ? POLLOUT | POLLWRNORM : 0; |
5e5d7a22 PE |
681 | /* |
682 | * Most Unices do not set POLLERR for FIFOs but on Linux they | |
683 | * behave exactly like pipes for poll(). | |
684 | */ | |
923f4f23 | 685 | if (!pipe->readers) |
1da177e4 LT |
686 | mask |= POLLERR; |
687 | } | |
688 | ||
689 | return mask; | |
690 | } | |
691 | ||
b0d8d229 LT |
692 | static void put_pipe_info(struct inode *inode, struct pipe_inode_info *pipe) |
693 | { | |
694 | int kill = 0; | |
695 | ||
696 | spin_lock(&inode->i_lock); | |
697 | if (!--pipe->files) { | |
698 | inode->i_pipe = NULL; | |
699 | kill = 1; | |
700 | } | |
701 | spin_unlock(&inode->i_lock); | |
702 | ||
703 | if (kill) | |
704 | free_pipe_info(pipe); | |
705 | } | |
706 | ||
1da177e4 | 707 | static int |
599a0ac1 | 708 | pipe_release(struct inode *inode, struct file *file) |
1da177e4 | 709 | { |
b0d8d229 | 710 | struct pipe_inode_info *pipe = file->private_data; |
923f4f23 | 711 | |
ebec73f4 | 712 | __pipe_lock(pipe); |
599a0ac1 AV |
713 | if (file->f_mode & FMODE_READ) |
714 | pipe->readers--; | |
715 | if (file->f_mode & FMODE_WRITE) | |
716 | pipe->writers--; | |
341b446b | 717 | |
ba5bb147 | 718 | if (pipe->readers || pipe->writers) { |
28e58ee8 | 719 | wake_up_interruptible_sync_poll(&pipe->wait, POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM | POLLERR | POLLHUP); |
923f4f23 IM |
720 | kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); |
721 | kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); | |
1da177e4 | 722 | } |
ebec73f4 | 723 | __pipe_unlock(pipe); |
ba5bb147 | 724 | |
b0d8d229 | 725 | put_pipe_info(inode, pipe); |
1da177e4 LT |
726 | return 0; |
727 | } | |
728 | ||
729 | static int | |
599a0ac1 | 730 | pipe_fasync(int fd, struct file *filp, int on) |
1da177e4 | 731 | { |
de32ec4c | 732 | struct pipe_inode_info *pipe = filp->private_data; |
599a0ac1 | 733 | int retval = 0; |
1da177e4 | 734 | |
ebec73f4 | 735 | __pipe_lock(pipe); |
599a0ac1 AV |
736 | if (filp->f_mode & FMODE_READ) |
737 | retval = fasync_helper(fd, filp, on, &pipe->fasync_readers); | |
738 | if ((filp->f_mode & FMODE_WRITE) && retval >= 0) { | |
341b446b | 739 | retval = fasync_helper(fd, filp, on, &pipe->fasync_writers); |
599a0ac1 AV |
740 | if (retval < 0 && (filp->f_mode & FMODE_READ)) |
741 | /* this can happen only if on == T */ | |
e5bc49ba ON |
742 | fasync_helper(-1, filp, 0, &pipe->fasync_readers); |
743 | } | |
ebec73f4 | 744 | __pipe_unlock(pipe); |
60aa4924 | 745 | return retval; |
1da177e4 LT |
746 | } |
747 | ||
7bee130e | 748 | struct pipe_inode_info *alloc_pipe_info(void) |
3a326a2c | 749 | { |
923f4f23 | 750 | struct pipe_inode_info *pipe; |
3a326a2c | 751 | |
923f4f23 IM |
752 | pipe = kzalloc(sizeof(struct pipe_inode_info), GFP_KERNEL); |
753 | if (pipe) { | |
35f3d14d JA |
754 | pipe->bufs = kzalloc(sizeof(struct pipe_buffer) * PIPE_DEF_BUFFERS, GFP_KERNEL); |
755 | if (pipe->bufs) { | |
756 | init_waitqueue_head(&pipe->wait); | |
757 | pipe->r_counter = pipe->w_counter = 1; | |
35f3d14d | 758 | pipe->buffers = PIPE_DEF_BUFFERS; |
72b0d9aa | 759 | mutex_init(&pipe->mutex); |
35f3d14d JA |
760 | return pipe; |
761 | } | |
762 | kfree(pipe); | |
3a326a2c IM |
763 | } |
764 | ||
35f3d14d | 765 | return NULL; |
3a326a2c IM |
766 | } |
767 | ||
4b8a8f1e | 768 | void free_pipe_info(struct pipe_inode_info *pipe) |
1da177e4 LT |
769 | { |
770 | int i; | |
1da177e4 | 771 | |
35f3d14d | 772 | for (i = 0; i < pipe->buffers; i++) { |
923f4f23 | 773 | struct pipe_buffer *buf = pipe->bufs + i; |
1da177e4 | 774 | if (buf->ops) |
923f4f23 | 775 | buf->ops->release(pipe, buf); |
1da177e4 | 776 | } |
923f4f23 IM |
777 | if (pipe->tmp_page) |
778 | __free_page(pipe->tmp_page); | |
35f3d14d | 779 | kfree(pipe->bufs); |
923f4f23 | 780 | kfree(pipe); |
1da177e4 LT |
781 | } |
782 | ||
fa3536cc | 783 | static struct vfsmount *pipe_mnt __read_mostly; |
341b446b | 784 | |
c23fbb6b ED |
785 | /* |
786 | * pipefs_dname() is called from d_path(). | |
787 | */ | |
788 | static char *pipefs_dname(struct dentry *dentry, char *buffer, int buflen) | |
789 | { | |
790 | return dynamic_dname(dentry, buffer, buflen, "pipe:[%lu]", | |
791 | dentry->d_inode->i_ino); | |
792 | } | |
793 | ||
3ba13d17 | 794 | static const struct dentry_operations pipefs_dentry_operations = { |
c23fbb6b | 795 | .d_dname = pipefs_dname, |
1da177e4 LT |
796 | }; |
797 | ||
798 | static struct inode * get_pipe_inode(void) | |
799 | { | |
a209dfc7 | 800 | struct inode *inode = new_inode_pseudo(pipe_mnt->mnt_sb); |
923f4f23 | 801 | struct pipe_inode_info *pipe; |
1da177e4 LT |
802 | |
803 | if (!inode) | |
804 | goto fail_inode; | |
805 | ||
85fe4025 CH |
806 | inode->i_ino = get_next_ino(); |
807 | ||
7bee130e | 808 | pipe = alloc_pipe_info(); |
923f4f23 | 809 | if (!pipe) |
1da177e4 | 810 | goto fail_iput; |
3a326a2c | 811 | |
ba5bb147 AV |
812 | inode->i_pipe = pipe; |
813 | pipe->files = 2; | |
923f4f23 | 814 | pipe->readers = pipe->writers = 1; |
599a0ac1 | 815 | inode->i_fop = &pipefifo_fops; |
1da177e4 LT |
816 | |
817 | /* | |
818 | * Mark the inode dirty from the very beginning, | |
819 | * that way it will never be moved to the dirty | |
820 | * list because "mark_inode_dirty()" will think | |
821 | * that it already _is_ on the dirty list. | |
822 | */ | |
823 | inode->i_state = I_DIRTY; | |
824 | inode->i_mode = S_IFIFO | S_IRUSR | S_IWUSR; | |
da9592ed DH |
825 | inode->i_uid = current_fsuid(); |
826 | inode->i_gid = current_fsgid(); | |
1da177e4 | 827 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; |
923f4f23 | 828 | |
1da177e4 LT |
829 | return inode; |
830 | ||
831 | fail_iput: | |
832 | iput(inode); | |
341b446b | 833 | |
1da177e4 LT |
834 | fail_inode: |
835 | return NULL; | |
836 | } | |
837 | ||
e4fad8e5 | 838 | int create_pipe_files(struct file **res, int flags) |
1da177e4 | 839 | { |
d6cbd281 | 840 | int err; |
e4fad8e5 | 841 | struct inode *inode = get_pipe_inode(); |
d6cbd281 | 842 | struct file *f; |
2c48b9c4 | 843 | struct path path; |
e4fad8e5 | 844 | static struct qstr name = { .name = "" }; |
1da177e4 | 845 | |
1da177e4 | 846 | if (!inode) |
e4fad8e5 | 847 | return -ENFILE; |
1da177e4 | 848 | |
d6cbd281 | 849 | err = -ENOMEM; |
4b936885 | 850 | path.dentry = d_alloc_pseudo(pipe_mnt->mnt_sb, &name); |
2c48b9c4 | 851 | if (!path.dentry) |
d6cbd281 | 852 | goto err_inode; |
2c48b9c4 | 853 | path.mnt = mntget(pipe_mnt); |
341b446b | 854 | |
2c48b9c4 | 855 | d_instantiate(path.dentry, inode); |
430e285e DH |
856 | |
857 | err = -ENFILE; | |
599a0ac1 | 858 | f = alloc_file(&path, FMODE_WRITE, &pipefifo_fops); |
39b65252 | 859 | if (IS_ERR(f)) |
430e285e | 860 | goto err_dentry; |
341b446b | 861 | |
9883035a | 862 | f->f_flags = O_WRONLY | (flags & (O_NONBLOCK | O_DIRECT)); |
de32ec4c | 863 | f->private_data = inode->i_pipe; |
d6cbd281 | 864 | |
599a0ac1 | 865 | res[0] = alloc_file(&path, FMODE_READ, &pipefifo_fops); |
39b65252 | 866 | if (IS_ERR(res[0])) |
e4fad8e5 AV |
867 | goto err_file; |
868 | ||
869 | path_get(&path); | |
de32ec4c | 870 | res[0]->private_data = inode->i_pipe; |
e4fad8e5 AV |
871 | res[0]->f_flags = O_RDONLY | (flags & O_NONBLOCK); |
872 | res[1] = f; | |
873 | return 0; | |
1da177e4 | 874 | |
e4fad8e5 AV |
875 | err_file: |
876 | put_filp(f); | |
877 | err_dentry: | |
4b8a8f1e | 878 | free_pipe_info(inode->i_pipe); |
2c48b9c4 | 879 | path_put(&path); |
e4fad8e5 | 880 | return err; |
ed152437 | 881 | |
e4fad8e5 | 882 | err_inode: |
4b8a8f1e | 883 | free_pipe_info(inode->i_pipe); |
1da177e4 | 884 | iput(inode); |
e4fad8e5 | 885 | return err; |
d6cbd281 AK |
886 | } |
887 | ||
5b249b1b | 888 | static int __do_pipe_flags(int *fd, struct file **files, int flags) |
d6cbd281 | 889 | { |
d6cbd281 AK |
890 | int error; |
891 | int fdw, fdr; | |
892 | ||
9883035a | 893 | if (flags & ~(O_CLOEXEC | O_NONBLOCK | O_DIRECT)) |
ed8cae8b UD |
894 | return -EINVAL; |
895 | ||
e4fad8e5 AV |
896 | error = create_pipe_files(files, flags); |
897 | if (error) | |
898 | return error; | |
d6cbd281 | 899 | |
ed8cae8b | 900 | error = get_unused_fd_flags(flags); |
d6cbd281 AK |
901 | if (error < 0) |
902 | goto err_read_pipe; | |
903 | fdr = error; | |
904 | ||
ed8cae8b | 905 | error = get_unused_fd_flags(flags); |
d6cbd281 AK |
906 | if (error < 0) |
907 | goto err_fdr; | |
908 | fdw = error; | |
909 | ||
157cf649 | 910 | audit_fd_pair(fdr, fdw); |
d6cbd281 AK |
911 | fd[0] = fdr; |
912 | fd[1] = fdw; | |
d6cbd281 AK |
913 | return 0; |
914 | ||
915 | err_fdr: | |
916 | put_unused_fd(fdr); | |
917 | err_read_pipe: | |
e4fad8e5 AV |
918 | fput(files[0]); |
919 | fput(files[1]); | |
d6cbd281 | 920 | return error; |
1da177e4 LT |
921 | } |
922 | ||
5b249b1b AV |
923 | int do_pipe_flags(int *fd, int flags) |
924 | { | |
925 | struct file *files[2]; | |
926 | int error = __do_pipe_flags(fd, files, flags); | |
927 | if (!error) { | |
928 | fd_install(fd[0], files[0]); | |
929 | fd_install(fd[1], files[1]); | |
930 | } | |
931 | return error; | |
932 | } | |
933 | ||
d35c7b0e UD |
934 | /* |
935 | * sys_pipe() is the normal C calling standard for creating | |
936 | * a pipe. It's not the way Unix traditionally does this, though. | |
937 | */ | |
d4e82042 | 938 | SYSCALL_DEFINE2(pipe2, int __user *, fildes, int, flags) |
d35c7b0e | 939 | { |
5b249b1b | 940 | struct file *files[2]; |
d35c7b0e UD |
941 | int fd[2]; |
942 | int error; | |
943 | ||
5b249b1b | 944 | error = __do_pipe_flags(fd, files, flags); |
d35c7b0e | 945 | if (!error) { |
5b249b1b AV |
946 | if (unlikely(copy_to_user(fildes, fd, sizeof(fd)))) { |
947 | fput(files[0]); | |
948 | fput(files[1]); | |
949 | put_unused_fd(fd[0]); | |
950 | put_unused_fd(fd[1]); | |
d35c7b0e | 951 | error = -EFAULT; |
5b249b1b AV |
952 | } else { |
953 | fd_install(fd[0], files[0]); | |
954 | fd_install(fd[1], files[1]); | |
ba719bae | 955 | } |
d35c7b0e UD |
956 | } |
957 | return error; | |
958 | } | |
959 | ||
2b664219 | 960 | SYSCALL_DEFINE1(pipe, int __user *, fildes) |
ed8cae8b UD |
961 | { |
962 | return sys_pipe2(fildes, 0); | |
963 | } | |
964 | ||
fc7478a2 | 965 | static int wait_for_partner(struct pipe_inode_info *pipe, unsigned int *cnt) |
f776c738 AV |
966 | { |
967 | int cur = *cnt; | |
968 | ||
969 | while (cur == *cnt) { | |
fc7478a2 | 970 | pipe_wait(pipe); |
f776c738 AV |
971 | if (signal_pending(current)) |
972 | break; | |
973 | } | |
974 | return cur == *cnt ? -ERESTARTSYS : 0; | |
975 | } | |
976 | ||
fc7478a2 | 977 | static void wake_up_partner(struct pipe_inode_info *pipe) |
f776c738 | 978 | { |
fc7478a2 | 979 | wake_up_interruptible(&pipe->wait); |
f776c738 AV |
980 | } |
981 | ||
982 | static int fifo_open(struct inode *inode, struct file *filp) | |
983 | { | |
984 | struct pipe_inode_info *pipe; | |
599a0ac1 | 985 | bool is_pipe = inode->i_sb->s_magic == PIPEFS_MAGIC; |
f776c738 AV |
986 | int ret; |
987 | ||
ba5bb147 AV |
988 | filp->f_version = 0; |
989 | ||
990 | spin_lock(&inode->i_lock); | |
991 | if (inode->i_pipe) { | |
992 | pipe = inode->i_pipe; | |
993 | pipe->files++; | |
994 | spin_unlock(&inode->i_lock); | |
995 | } else { | |
996 | spin_unlock(&inode->i_lock); | |
7bee130e | 997 | pipe = alloc_pipe_info(); |
f776c738 | 998 | if (!pipe) |
ba5bb147 AV |
999 | return -ENOMEM; |
1000 | pipe->files = 1; | |
1001 | spin_lock(&inode->i_lock); | |
1002 | if (unlikely(inode->i_pipe)) { | |
1003 | inode->i_pipe->files++; | |
1004 | spin_unlock(&inode->i_lock); | |
4b8a8f1e | 1005 | free_pipe_info(pipe); |
ba5bb147 AV |
1006 | pipe = inode->i_pipe; |
1007 | } else { | |
1008 | inode->i_pipe = pipe; | |
1009 | spin_unlock(&inode->i_lock); | |
1010 | } | |
f776c738 | 1011 | } |
de32ec4c | 1012 | filp->private_data = pipe; |
ba5bb147 AV |
1013 | /* OK, we have a pipe and it's pinned down */ |
1014 | ||
ebec73f4 | 1015 | __pipe_lock(pipe); |
f776c738 AV |
1016 | |
1017 | /* We can only do regular read/write on fifos */ | |
1018 | filp->f_mode &= (FMODE_READ | FMODE_WRITE); | |
1019 | ||
1020 | switch (filp->f_mode) { | |
1021 | case FMODE_READ: | |
1022 | /* | |
1023 | * O_RDONLY | |
1024 | * POSIX.1 says that O_NONBLOCK means return with the FIFO | |
1025 | * opened, even when there is no process writing the FIFO. | |
1026 | */ | |
f776c738 AV |
1027 | pipe->r_counter++; |
1028 | if (pipe->readers++ == 0) | |
fc7478a2 | 1029 | wake_up_partner(pipe); |
f776c738 | 1030 | |
599a0ac1 | 1031 | if (!is_pipe && !pipe->writers) { |
f776c738 AV |
1032 | if ((filp->f_flags & O_NONBLOCK)) { |
1033 | /* suppress POLLHUP until we have | |
1034 | * seen a writer */ | |
1035 | filp->f_version = pipe->w_counter; | |
1036 | } else { | |
fc7478a2 | 1037 | if (wait_for_partner(pipe, &pipe->w_counter)) |
f776c738 AV |
1038 | goto err_rd; |
1039 | } | |
1040 | } | |
1041 | break; | |
1042 | ||
1043 | case FMODE_WRITE: | |
1044 | /* | |
1045 | * O_WRONLY | |
1046 | * POSIX.1 says that O_NONBLOCK means return -1 with | |
1047 | * errno=ENXIO when there is no process reading the FIFO. | |
1048 | */ | |
1049 | ret = -ENXIO; | |
599a0ac1 | 1050 | if (!is_pipe && (filp->f_flags & O_NONBLOCK) && !pipe->readers) |
f776c738 AV |
1051 | goto err; |
1052 | ||
f776c738 AV |
1053 | pipe->w_counter++; |
1054 | if (!pipe->writers++) | |
fc7478a2 | 1055 | wake_up_partner(pipe); |
f776c738 | 1056 | |
599a0ac1 | 1057 | if (!is_pipe && !pipe->readers) { |
fc7478a2 | 1058 | if (wait_for_partner(pipe, &pipe->r_counter)) |
f776c738 AV |
1059 | goto err_wr; |
1060 | } | |
1061 | break; | |
1062 | ||
1063 | case FMODE_READ | FMODE_WRITE: | |
1064 | /* | |
1065 | * O_RDWR | |
1066 | * POSIX.1 leaves this case "undefined" when O_NONBLOCK is set. | |
1067 | * This implementation will NEVER block on a O_RDWR open, since | |
1068 | * the process can at least talk to itself. | |
1069 | */ | |
f776c738 AV |
1070 | |
1071 | pipe->readers++; | |
1072 | pipe->writers++; | |
1073 | pipe->r_counter++; | |
1074 | pipe->w_counter++; | |
1075 | if (pipe->readers == 1 || pipe->writers == 1) | |
fc7478a2 | 1076 | wake_up_partner(pipe); |
f776c738 AV |
1077 | break; |
1078 | ||
1079 | default: | |
1080 | ret = -EINVAL; | |
1081 | goto err; | |
1082 | } | |
1083 | ||
1084 | /* Ok! */ | |
ebec73f4 | 1085 | __pipe_unlock(pipe); |
f776c738 AV |
1086 | return 0; |
1087 | ||
1088 | err_rd: | |
1089 | if (!--pipe->readers) | |
1090 | wake_up_interruptible(&pipe->wait); | |
1091 | ret = -ERESTARTSYS; | |
1092 | goto err; | |
1093 | ||
1094 | err_wr: | |
1095 | if (!--pipe->writers) | |
1096 | wake_up_interruptible(&pipe->wait); | |
1097 | ret = -ERESTARTSYS; | |
1098 | goto err; | |
1099 | ||
1100 | err: | |
ebec73f4 | 1101 | __pipe_unlock(pipe); |
b0d8d229 LT |
1102 | |
1103 | put_pipe_info(inode, pipe); | |
f776c738 AV |
1104 | return ret; |
1105 | } | |
1106 | ||
599a0ac1 AV |
1107 | const struct file_operations pipefifo_fops = { |
1108 | .open = fifo_open, | |
1109 | .llseek = no_llseek, | |
1110 | .read = do_sync_read, | |
1111 | .aio_read = pipe_read, | |
1112 | .write = do_sync_write, | |
1113 | .aio_write = pipe_write, | |
1114 | .poll = pipe_poll, | |
1115 | .unlocked_ioctl = pipe_ioctl, | |
1116 | .release = pipe_release, | |
1117 | .fasync = pipe_fasync, | |
f776c738 AV |
1118 | }; |
1119 | ||
35f3d14d JA |
1120 | /* |
1121 | * Allocate a new array of pipe buffers and copy the info over. Returns the | |
1122 | * pipe size if successful, or return -ERROR on error. | |
1123 | */ | |
b9598db3 | 1124 | static long pipe_set_size(struct pipe_inode_info *pipe, unsigned long nr_pages) |
35f3d14d JA |
1125 | { |
1126 | struct pipe_buffer *bufs; | |
1127 | ||
35f3d14d JA |
1128 | /* |
1129 | * We can shrink the pipe, if arg >= pipe->nrbufs. Since we don't | |
1130 | * expect a lot of shrink+grow operations, just free and allocate | |
1131 | * again like we would do for growing. If the pipe currently | |
1132 | * contains more buffers than arg, then return busy. | |
1133 | */ | |
b9598db3 | 1134 | if (nr_pages < pipe->nrbufs) |
35f3d14d JA |
1135 | return -EBUSY; |
1136 | ||
2ccd4f4d | 1137 | bufs = kcalloc(nr_pages, sizeof(*bufs), GFP_KERNEL | __GFP_NOWARN); |
35f3d14d JA |
1138 | if (unlikely(!bufs)) |
1139 | return -ENOMEM; | |
1140 | ||
1141 | /* | |
1142 | * The pipe array wraps around, so just start the new one at zero | |
1143 | * and adjust the indexes. | |
1144 | */ | |
1145 | if (pipe->nrbufs) { | |
1d862f41 MS |
1146 | unsigned int tail; |
1147 | unsigned int head; | |
35f3d14d | 1148 | |
1d862f41 MS |
1149 | tail = pipe->curbuf + pipe->nrbufs; |
1150 | if (tail < pipe->buffers) | |
1151 | tail = 0; | |
1152 | else | |
1153 | tail &= (pipe->buffers - 1); | |
1154 | ||
1155 | head = pipe->nrbufs - tail; | |
35f3d14d JA |
1156 | if (head) |
1157 | memcpy(bufs, pipe->bufs + pipe->curbuf, head * sizeof(struct pipe_buffer)); | |
1158 | if (tail) | |
1d862f41 | 1159 | memcpy(bufs + head, pipe->bufs, tail * sizeof(struct pipe_buffer)); |
35f3d14d JA |
1160 | } |
1161 | ||
1162 | pipe->curbuf = 0; | |
1163 | kfree(pipe->bufs); | |
1164 | pipe->bufs = bufs; | |
b9598db3 JA |
1165 | pipe->buffers = nr_pages; |
1166 | return nr_pages * PAGE_SIZE; | |
35f3d14d JA |
1167 | } |
1168 | ||
ff9da691 JA |
1169 | /* |
1170 | * Currently we rely on the pipe array holding a power-of-2 number | |
1171 | * of pages. | |
1172 | */ | |
1173 | static inline unsigned int round_pipe_size(unsigned int size) | |
1174 | { | |
1175 | unsigned long nr_pages; | |
1176 | ||
1177 | nr_pages = (size + PAGE_SIZE - 1) >> PAGE_SHIFT; | |
1178 | return roundup_pow_of_two(nr_pages) << PAGE_SHIFT; | |
1179 | } | |
1180 | ||
1181 | /* | |
1182 | * This should work even if CONFIG_PROC_FS isn't set, as proc_dointvec_minmax | |
1183 | * will return an error. | |
1184 | */ | |
1185 | int pipe_proc_fn(struct ctl_table *table, int write, void __user *buf, | |
1186 | size_t *lenp, loff_t *ppos) | |
1187 | { | |
1188 | int ret; | |
1189 | ||
1190 | ret = proc_dointvec_minmax(table, write, buf, lenp, ppos); | |
1191 | if (ret < 0 || !write) | |
1192 | return ret; | |
1193 | ||
1194 | pipe_max_size = round_pipe_size(pipe_max_size); | |
1195 | return ret; | |
1196 | } | |
1197 | ||
72083646 LT |
1198 | /* |
1199 | * After the inode slimming patch, i_pipe/i_bdev/i_cdev share the same | |
1200 | * location, so checking ->i_pipe is not enough to verify that this is a | |
1201 | * pipe. | |
1202 | */ | |
1203 | struct pipe_inode_info *get_pipe_info(struct file *file) | |
1204 | { | |
de32ec4c | 1205 | return file->f_op == &pipefifo_fops ? file->private_data : NULL; |
72083646 LT |
1206 | } |
1207 | ||
35f3d14d JA |
1208 | long pipe_fcntl(struct file *file, unsigned int cmd, unsigned long arg) |
1209 | { | |
1210 | struct pipe_inode_info *pipe; | |
1211 | long ret; | |
1212 | ||
c66fb347 | 1213 | pipe = get_pipe_info(file); |
35f3d14d JA |
1214 | if (!pipe) |
1215 | return -EBADF; | |
1216 | ||
ebec73f4 | 1217 | __pipe_lock(pipe); |
35f3d14d JA |
1218 | |
1219 | switch (cmd) { | |
b9598db3 | 1220 | case F_SETPIPE_SZ: { |
ff9da691 | 1221 | unsigned int size, nr_pages; |
b9598db3 | 1222 | |
ff9da691 JA |
1223 | size = round_pipe_size(arg); |
1224 | nr_pages = size >> PAGE_SHIFT; | |
b9598db3 | 1225 | |
6db40cf0 MS |
1226 | ret = -EINVAL; |
1227 | if (!nr_pages) | |
1228 | goto out; | |
1229 | ||
ff9da691 | 1230 | if (!capable(CAP_SYS_RESOURCE) && size > pipe_max_size) { |
b4ca7615 | 1231 | ret = -EPERM; |
cc967be5 | 1232 | goto out; |
cc967be5 | 1233 | } |
ff9da691 | 1234 | ret = pipe_set_size(pipe, nr_pages); |
35f3d14d | 1235 | break; |
b9598db3 | 1236 | } |
35f3d14d | 1237 | case F_GETPIPE_SZ: |
b9598db3 | 1238 | ret = pipe->buffers * PAGE_SIZE; |
35f3d14d JA |
1239 | break; |
1240 | default: | |
1241 | ret = -EINVAL; | |
1242 | break; | |
1243 | } | |
1244 | ||
cc967be5 | 1245 | out: |
ebec73f4 | 1246 | __pipe_unlock(pipe); |
35f3d14d JA |
1247 | return ret; |
1248 | } | |
1249 | ||
ff0c7d15 NP |
1250 | static const struct super_operations pipefs_ops = { |
1251 | .destroy_inode = free_inode_nonrcu, | |
d70ef97b | 1252 | .statfs = simple_statfs, |
ff0c7d15 NP |
1253 | }; |
1254 | ||
1da177e4 LT |
1255 | /* |
1256 | * pipefs should _never_ be mounted by userland - too much of security hassle, | |
1257 | * no real gain from having the whole whorehouse mounted. So we don't need | |
1258 | * any operations on the root directory. However, we need a non-trivial | |
1259 | * d_name - pipe: will go nicely and kill the special-casing in procfs. | |
1260 | */ | |
51139ada AV |
1261 | static struct dentry *pipefs_mount(struct file_system_type *fs_type, |
1262 | int flags, const char *dev_name, void *data) | |
1da177e4 | 1263 | { |
c74a1cbb AV |
1264 | return mount_pseudo(fs_type, "pipe:", &pipefs_ops, |
1265 | &pipefs_dentry_operations, PIPEFS_MAGIC); | |
1da177e4 LT |
1266 | } |
1267 | ||
1268 | static struct file_system_type pipe_fs_type = { | |
1269 | .name = "pipefs", | |
51139ada | 1270 | .mount = pipefs_mount, |
1da177e4 LT |
1271 | .kill_sb = kill_anon_super, |
1272 | }; | |
1273 | ||
1274 | static int __init init_pipe_fs(void) | |
1275 | { | |
1276 | int err = register_filesystem(&pipe_fs_type); | |
341b446b | 1277 | |
1da177e4 LT |
1278 | if (!err) { |
1279 | pipe_mnt = kern_mount(&pipe_fs_type); | |
1280 | if (IS_ERR(pipe_mnt)) { | |
1281 | err = PTR_ERR(pipe_mnt); | |
1282 | unregister_filesystem(&pipe_fs_type); | |
1283 | } | |
1284 | } | |
1285 | return err; | |
1286 | } | |
1287 | ||
1da177e4 | 1288 | fs_initcall(init_pipe_fs); |