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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> | |
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> |
1da177e4 LT |
24 | |
25 | #include <asm/uaccess.h> | |
26 | #include <asm/ioctls.h> | |
27 | ||
599a0ac1 AV |
28 | #include "internal.h" |
29 | ||
b492e95b JA |
30 | /* |
31 | * The max size that a non-root user is allowed to grow the pipe. Can | |
ff9da691 | 32 | * be set by root in /proc/sys/fs/pipe-max-size |
b492e95b | 33 | */ |
ff9da691 JA |
34 | unsigned int pipe_max_size = 1048576; |
35 | ||
36 | /* | |
37 | * Minimum pipe size, as required by POSIX | |
38 | */ | |
39 | unsigned int pipe_min_size = PAGE_SIZE; | |
b492e95b | 40 | |
1da177e4 LT |
41 | /* |
42 | * We use a start+len construction, which provides full use of the | |
43 | * allocated memory. | |
44 | * -- Florian Coosmann (FGC) | |
45 | * | |
46 | * Reads with count = 0 should always return 0. | |
47 | * -- Julian Bradfield 1999-06-07. | |
48 | * | |
49 | * FIFOs and Pipes now generate SIGIO for both readers and writers. | |
50 | * -- Jeremy Elson <jelson@circlemud.org> 2001-08-16 | |
51 | * | |
52 | * pipe_read & write cleanup | |
53 | * -- Manfred Spraul <manfred@colorfullife.com> 2002-05-09 | |
54 | */ | |
55 | ||
61e0d47c MS |
56 | static void pipe_lock_nested(struct pipe_inode_info *pipe, int subclass) |
57 | { | |
6447a3cf | 58 | if (pipe->files) |
72b0d9aa | 59 | mutex_lock_nested(&pipe->mutex, subclass); |
61e0d47c MS |
60 | } |
61 | ||
62 | void pipe_lock(struct pipe_inode_info *pipe) | |
63 | { | |
64 | /* | |
65 | * pipe_lock() nests non-pipe inode locks (for writing to a file) | |
66 | */ | |
67 | pipe_lock_nested(pipe, I_MUTEX_PARENT); | |
68 | } | |
69 | EXPORT_SYMBOL(pipe_lock); | |
70 | ||
71 | void pipe_unlock(struct pipe_inode_info *pipe) | |
72 | { | |
6447a3cf | 73 | if (pipe->files) |
72b0d9aa | 74 | mutex_unlock(&pipe->mutex); |
61e0d47c MS |
75 | } |
76 | EXPORT_SYMBOL(pipe_unlock); | |
77 | ||
ebec73f4 AV |
78 | static inline void __pipe_lock(struct pipe_inode_info *pipe) |
79 | { | |
80 | mutex_lock_nested(&pipe->mutex, I_MUTEX_PARENT); | |
81 | } | |
82 | ||
83 | static inline void __pipe_unlock(struct pipe_inode_info *pipe) | |
84 | { | |
85 | mutex_unlock(&pipe->mutex); | |
86 | } | |
87 | ||
61e0d47c MS |
88 | void pipe_double_lock(struct pipe_inode_info *pipe1, |
89 | struct pipe_inode_info *pipe2) | |
90 | { | |
91 | BUG_ON(pipe1 == pipe2); | |
92 | ||
93 | if (pipe1 < pipe2) { | |
94 | pipe_lock_nested(pipe1, I_MUTEX_PARENT); | |
95 | pipe_lock_nested(pipe2, I_MUTEX_CHILD); | |
96 | } else { | |
023d43c7 PZ |
97 | pipe_lock_nested(pipe2, I_MUTEX_PARENT); |
98 | pipe_lock_nested(pipe1, I_MUTEX_CHILD); | |
61e0d47c MS |
99 | } |
100 | } | |
101 | ||
1da177e4 | 102 | /* Drop the inode semaphore and wait for a pipe event, atomically */ |
3a326a2c | 103 | void pipe_wait(struct pipe_inode_info *pipe) |
1da177e4 LT |
104 | { |
105 | DEFINE_WAIT(wait); | |
106 | ||
d79fc0fc IM |
107 | /* |
108 | * Pipes are system-local resources, so sleeping on them | |
109 | * is considered a noninteractive wait: | |
110 | */ | |
af927232 | 111 | prepare_to_wait(&pipe->wait, &wait, TASK_INTERRUPTIBLE); |
61e0d47c | 112 | pipe_unlock(pipe); |
1da177e4 | 113 | schedule(); |
3a326a2c | 114 | finish_wait(&pipe->wait, &wait); |
61e0d47c | 115 | pipe_lock(pipe); |
1da177e4 LT |
116 | } |
117 | ||
858119e1 | 118 | static int |
f6762b7a JA |
119 | pipe_iov_copy_from_user(void *to, struct iovec *iov, unsigned long len, |
120 | int atomic) | |
1da177e4 LT |
121 | { |
122 | unsigned long copy; | |
123 | ||
124 | while (len > 0) { | |
125 | while (!iov->iov_len) | |
126 | iov++; | |
127 | copy = min_t(unsigned long, len, iov->iov_len); | |
128 | ||
f6762b7a JA |
129 | if (atomic) { |
130 | if (__copy_from_user_inatomic(to, iov->iov_base, copy)) | |
131 | return -EFAULT; | |
132 | } else { | |
133 | if (copy_from_user(to, iov->iov_base, copy)) | |
134 | return -EFAULT; | |
135 | } | |
1da177e4 LT |
136 | to += copy; |
137 | len -= copy; | |
138 | iov->iov_base += copy; | |
139 | iov->iov_len -= copy; | |
140 | } | |
141 | return 0; | |
142 | } | |
143 | ||
858119e1 | 144 | static int |
f6762b7a JA |
145 | pipe_iov_copy_to_user(struct iovec *iov, const void *from, unsigned long len, |
146 | int atomic) | |
1da177e4 LT |
147 | { |
148 | unsigned long copy; | |
149 | ||
150 | while (len > 0) { | |
151 | while (!iov->iov_len) | |
152 | iov++; | |
153 | copy = min_t(unsigned long, len, iov->iov_len); | |
154 | ||
f6762b7a JA |
155 | if (atomic) { |
156 | if (__copy_to_user_inatomic(iov->iov_base, from, copy)) | |
157 | return -EFAULT; | |
158 | } else { | |
159 | if (copy_to_user(iov->iov_base, from, copy)) | |
160 | return -EFAULT; | |
161 | } | |
1da177e4 LT |
162 | from += copy; |
163 | len -= copy; | |
164 | iov->iov_base += copy; | |
165 | iov->iov_len -= copy; | |
166 | } | |
167 | return 0; | |
168 | } | |
169 | ||
f6762b7a JA |
170 | /* |
171 | * Attempt to pre-fault in the user memory, so we can use atomic copies. | |
172 | * Returns the number of bytes not faulted in. | |
173 | */ | |
174 | static int iov_fault_in_pages_write(struct iovec *iov, unsigned long len) | |
175 | { | |
176 | while (!iov->iov_len) | |
177 | iov++; | |
178 | ||
179 | while (len > 0) { | |
180 | unsigned long this_len; | |
181 | ||
182 | this_len = min_t(unsigned long, len, iov->iov_len); | |
183 | if (fault_in_pages_writeable(iov->iov_base, this_len)) | |
184 | break; | |
185 | ||
186 | len -= this_len; | |
187 | iov++; | |
188 | } | |
189 | ||
190 | return len; | |
191 | } | |
192 | ||
193 | /* | |
194 | * Pre-fault in the user memory, so we can use atomic copies. | |
195 | */ | |
196 | static void iov_fault_in_pages_read(struct iovec *iov, unsigned long len) | |
197 | { | |
198 | while (!iov->iov_len) | |
199 | iov++; | |
200 | ||
201 | while (len > 0) { | |
202 | unsigned long this_len; | |
203 | ||
204 | this_len = min_t(unsigned long, len, iov->iov_len); | |
205 | fault_in_pages_readable(iov->iov_base, this_len); | |
206 | len -= this_len; | |
207 | iov++; | |
208 | } | |
209 | } | |
210 | ||
341b446b IM |
211 | static void anon_pipe_buf_release(struct pipe_inode_info *pipe, |
212 | struct pipe_buffer *buf) | |
1da177e4 LT |
213 | { |
214 | struct page *page = buf->page; | |
215 | ||
5274f052 JA |
216 | /* |
217 | * If nobody else uses this page, and we don't already have a | |
218 | * temporary page, let's keep track of it as a one-deep | |
341b446b | 219 | * allocation cache. (Otherwise just release our reference to it) |
5274f052 | 220 | */ |
341b446b | 221 | if (page_count(page) == 1 && !pipe->tmp_page) |
923f4f23 | 222 | pipe->tmp_page = page; |
341b446b IM |
223 | else |
224 | page_cache_release(page); | |
1da177e4 LT |
225 | } |
226 | ||
0845718d JA |
227 | /** |
228 | * generic_pipe_buf_map - virtually map a pipe buffer | |
229 | * @pipe: the pipe that the buffer belongs to | |
230 | * @buf: the buffer that should be mapped | |
231 | * @atomic: whether to use an atomic map | |
232 | * | |
233 | * Description: | |
234 | * This function returns a kernel virtual address mapping for the | |
b51d63c6 | 235 | * pipe_buffer passed in @buf. If @atomic is set, an atomic map is provided |
0845718d JA |
236 | * and the caller has to be careful not to fault before calling |
237 | * the unmap function. | |
238 | * | |
2164d334 | 239 | * Note that this function calls kmap_atomic() if @atomic != 0. |
0845718d | 240 | */ |
f84d7519 | 241 | void *generic_pipe_buf_map(struct pipe_inode_info *pipe, |
f6762b7a | 242 | struct pipe_buffer *buf, int atomic) |
1da177e4 | 243 | { |
f6762b7a JA |
244 | if (atomic) { |
245 | buf->flags |= PIPE_BUF_FLAG_ATOMIC; | |
e8e3c3d6 | 246 | return kmap_atomic(buf->page); |
f6762b7a JA |
247 | } |
248 | ||
1da177e4 LT |
249 | return kmap(buf->page); |
250 | } | |
51921cb7 | 251 | EXPORT_SYMBOL(generic_pipe_buf_map); |
1da177e4 | 252 | |
0845718d JA |
253 | /** |
254 | * generic_pipe_buf_unmap - unmap a previously mapped pipe buffer | |
255 | * @pipe: the pipe that the buffer belongs to | |
256 | * @buf: the buffer that should be unmapped | |
257 | * @map_data: the data that the mapping function returned | |
258 | * | |
259 | * Description: | |
260 | * This function undoes the mapping that ->map() provided. | |
261 | */ | |
f84d7519 | 262 | void generic_pipe_buf_unmap(struct pipe_inode_info *pipe, |
f6762b7a | 263 | struct pipe_buffer *buf, void *map_data) |
1da177e4 | 264 | { |
f6762b7a JA |
265 | if (buf->flags & PIPE_BUF_FLAG_ATOMIC) { |
266 | buf->flags &= ~PIPE_BUF_FLAG_ATOMIC; | |
e8e3c3d6 | 267 | kunmap_atomic(map_data); |
f6762b7a JA |
268 | } else |
269 | kunmap(buf->page); | |
1da177e4 | 270 | } |
51921cb7 | 271 | EXPORT_SYMBOL(generic_pipe_buf_unmap); |
1da177e4 | 272 | |
0845718d | 273 | /** |
b51d63c6 | 274 | * generic_pipe_buf_steal - attempt to take ownership of a &pipe_buffer |
0845718d JA |
275 | * @pipe: the pipe that the buffer belongs to |
276 | * @buf: the buffer to attempt to steal | |
277 | * | |
278 | * Description: | |
b51d63c6 | 279 | * This function attempts to steal the &struct page attached to |
0845718d JA |
280 | * @buf. If successful, this function returns 0 and returns with |
281 | * the page locked. The caller may then reuse the page for whatever | |
b51d63c6 | 282 | * he wishes; the typical use is insertion into a different file |
0845718d JA |
283 | * page cache. |
284 | */ | |
330ab716 JA |
285 | int generic_pipe_buf_steal(struct pipe_inode_info *pipe, |
286 | struct pipe_buffer *buf) | |
5abc97aa | 287 | { |
46e678c9 JA |
288 | struct page *page = buf->page; |
289 | ||
0845718d JA |
290 | /* |
291 | * A reference of one is golden, that means that the owner of this | |
292 | * page is the only one holding a reference to it. lock the page | |
293 | * and return OK. | |
294 | */ | |
46e678c9 | 295 | if (page_count(page) == 1) { |
46e678c9 JA |
296 | lock_page(page); |
297 | return 0; | |
298 | } | |
299 | ||
300 | return 1; | |
5abc97aa | 301 | } |
51921cb7 | 302 | EXPORT_SYMBOL(generic_pipe_buf_steal); |
5abc97aa | 303 | |
0845718d | 304 | /** |
b51d63c6 | 305 | * generic_pipe_buf_get - get a reference to a &struct pipe_buffer |
0845718d JA |
306 | * @pipe: the pipe that the buffer belongs to |
307 | * @buf: the buffer to get a reference to | |
308 | * | |
309 | * Description: | |
310 | * This function grabs an extra reference to @buf. It's used in | |
311 | * in the tee() system call, when we duplicate the buffers in one | |
312 | * pipe into another. | |
313 | */ | |
314 | void generic_pipe_buf_get(struct pipe_inode_info *pipe, struct pipe_buffer *buf) | |
70524490 JA |
315 | { |
316 | page_cache_get(buf->page); | |
317 | } | |
51921cb7 | 318 | EXPORT_SYMBOL(generic_pipe_buf_get); |
70524490 | 319 | |
0845718d JA |
320 | /** |
321 | * generic_pipe_buf_confirm - verify contents of the pipe buffer | |
79685b8d | 322 | * @info: the pipe that the buffer belongs to |
0845718d JA |
323 | * @buf: the buffer to confirm |
324 | * | |
325 | * Description: | |
326 | * This function does nothing, because the generic pipe code uses | |
327 | * pages that are always good when inserted into the pipe. | |
328 | */ | |
cac36bb0 JA |
329 | int generic_pipe_buf_confirm(struct pipe_inode_info *info, |
330 | struct pipe_buffer *buf) | |
f84d7519 JA |
331 | { |
332 | return 0; | |
333 | } | |
51921cb7 | 334 | EXPORT_SYMBOL(generic_pipe_buf_confirm); |
f84d7519 | 335 | |
6818173b MS |
336 | /** |
337 | * generic_pipe_buf_release - put a reference to a &struct pipe_buffer | |
338 | * @pipe: the pipe that the buffer belongs to | |
339 | * @buf: the buffer to put a reference to | |
340 | * | |
341 | * Description: | |
342 | * This function releases a reference to @buf. | |
343 | */ | |
344 | void generic_pipe_buf_release(struct pipe_inode_info *pipe, | |
345 | struct pipe_buffer *buf) | |
346 | { | |
347 | page_cache_release(buf->page); | |
348 | } | |
51921cb7 | 349 | EXPORT_SYMBOL(generic_pipe_buf_release); |
6818173b | 350 | |
d4c3cca9 | 351 | static const struct pipe_buf_operations anon_pipe_buf_ops = { |
1da177e4 | 352 | .can_merge = 1, |
f84d7519 JA |
353 | .map = generic_pipe_buf_map, |
354 | .unmap = generic_pipe_buf_unmap, | |
cac36bb0 | 355 | .confirm = generic_pipe_buf_confirm, |
1da177e4 | 356 | .release = anon_pipe_buf_release, |
330ab716 | 357 | .steal = generic_pipe_buf_steal, |
f84d7519 | 358 | .get = generic_pipe_buf_get, |
1da177e4 LT |
359 | }; |
360 | ||
9883035a LT |
361 | static const struct pipe_buf_operations packet_pipe_buf_ops = { |
362 | .can_merge = 0, | |
363 | .map = generic_pipe_buf_map, | |
364 | .unmap = generic_pipe_buf_unmap, | |
365 | .confirm = generic_pipe_buf_confirm, | |
366 | .release = anon_pipe_buf_release, | |
367 | .steal = generic_pipe_buf_steal, | |
368 | .get = generic_pipe_buf_get, | |
369 | }; | |
370 | ||
1da177e4 | 371 | static ssize_t |
ee0b3e67 BP |
372 | pipe_read(struct kiocb *iocb, const struct iovec *_iov, |
373 | unsigned long nr_segs, loff_t pos) | |
1da177e4 | 374 | { |
ee0b3e67 | 375 | struct file *filp = iocb->ki_filp; |
de32ec4c | 376 | struct pipe_inode_info *pipe = filp->private_data; |
1da177e4 LT |
377 | int do_wakeup; |
378 | ssize_t ret; | |
379 | struct iovec *iov = (struct iovec *)_iov; | |
380 | size_t total_len; | |
381 | ||
382 | total_len = iov_length(iov, nr_segs); | |
383 | /* Null read succeeds. */ | |
384 | if (unlikely(total_len == 0)) | |
385 | return 0; | |
386 | ||
387 | do_wakeup = 0; | |
388 | ret = 0; | |
ebec73f4 | 389 | __pipe_lock(pipe); |
1da177e4 | 390 | for (;;) { |
923f4f23 | 391 | int bufs = pipe->nrbufs; |
1da177e4 | 392 | if (bufs) { |
923f4f23 IM |
393 | int curbuf = pipe->curbuf; |
394 | struct pipe_buffer *buf = pipe->bufs + curbuf; | |
d4c3cca9 | 395 | const struct pipe_buf_operations *ops = buf->ops; |
1da177e4 LT |
396 | void *addr; |
397 | size_t chars = buf->len; | |
f6762b7a | 398 | int error, atomic; |
1da177e4 LT |
399 | |
400 | if (chars > total_len) | |
401 | chars = total_len; | |
402 | ||
cac36bb0 | 403 | error = ops->confirm(pipe, buf); |
f84d7519 | 404 | if (error) { |
5274f052 | 405 | if (!ret) |
e5953cbd | 406 | ret = error; |
5274f052 JA |
407 | break; |
408 | } | |
f84d7519 | 409 | |
f6762b7a JA |
410 | atomic = !iov_fault_in_pages_write(iov, chars); |
411 | redo: | |
412 | addr = ops->map(pipe, buf, atomic); | |
413 | error = pipe_iov_copy_to_user(iov, addr + buf->offset, chars, atomic); | |
414 | ops->unmap(pipe, buf, addr); | |
1da177e4 | 415 | if (unlikely(error)) { |
f6762b7a JA |
416 | /* |
417 | * Just retry with the slow path if we failed. | |
418 | */ | |
419 | if (atomic) { | |
420 | atomic = 0; | |
421 | goto redo; | |
422 | } | |
341b446b | 423 | if (!ret) |
f6762b7a | 424 | ret = error; |
1da177e4 LT |
425 | break; |
426 | } | |
427 | ret += chars; | |
428 | buf->offset += chars; | |
429 | buf->len -= chars; | |
9883035a LT |
430 | |
431 | /* Was it a packet buffer? Clean up and exit */ | |
432 | if (buf->flags & PIPE_BUF_FLAG_PACKET) { | |
433 | total_len = chars; | |
434 | buf->len = 0; | |
435 | } | |
436 | ||
1da177e4 LT |
437 | if (!buf->len) { |
438 | buf->ops = NULL; | |
923f4f23 | 439 | ops->release(pipe, buf); |
35f3d14d | 440 | curbuf = (curbuf + 1) & (pipe->buffers - 1); |
923f4f23 IM |
441 | pipe->curbuf = curbuf; |
442 | pipe->nrbufs = --bufs; | |
1da177e4 LT |
443 | do_wakeup = 1; |
444 | } | |
445 | total_len -= chars; | |
446 | if (!total_len) | |
447 | break; /* common path: read succeeded */ | |
448 | } | |
449 | if (bufs) /* More to do? */ | |
450 | continue; | |
923f4f23 | 451 | if (!pipe->writers) |
1da177e4 | 452 | break; |
923f4f23 | 453 | if (!pipe->waiting_writers) { |
1da177e4 LT |
454 | /* syscall merging: Usually we must not sleep |
455 | * if O_NONBLOCK is set, or if we got some data. | |
456 | * But if a writer sleeps in kernel space, then | |
457 | * we can wait for that data without violating POSIX. | |
458 | */ | |
459 | if (ret) | |
460 | break; | |
461 | if (filp->f_flags & O_NONBLOCK) { | |
462 | ret = -EAGAIN; | |
463 | break; | |
464 | } | |
465 | } | |
466 | if (signal_pending(current)) { | |
341b446b IM |
467 | if (!ret) |
468 | ret = -ERESTARTSYS; | |
1da177e4 LT |
469 | break; |
470 | } | |
471 | if (do_wakeup) { | |
28e58ee8 | 472 | wake_up_interruptible_sync_poll(&pipe->wait, POLLOUT | POLLWRNORM); |
923f4f23 | 473 | kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); |
1da177e4 | 474 | } |
923f4f23 | 475 | pipe_wait(pipe); |
1da177e4 | 476 | } |
ebec73f4 | 477 | __pipe_unlock(pipe); |
341b446b IM |
478 | |
479 | /* Signal writers asynchronously that there is more room. */ | |
1da177e4 | 480 | if (do_wakeup) { |
28e58ee8 | 481 | wake_up_interruptible_sync_poll(&pipe->wait, POLLOUT | POLLWRNORM); |
923f4f23 | 482 | kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); |
1da177e4 LT |
483 | } |
484 | if (ret > 0) | |
485 | file_accessed(filp); | |
486 | return ret; | |
487 | } | |
488 | ||
9883035a LT |
489 | static inline int is_packetized(struct file *file) |
490 | { | |
491 | return (file->f_flags & O_DIRECT) != 0; | |
492 | } | |
493 | ||
1da177e4 | 494 | static ssize_t |
ee0b3e67 BP |
495 | pipe_write(struct kiocb *iocb, const struct iovec *_iov, |
496 | unsigned long nr_segs, loff_t ppos) | |
1da177e4 | 497 | { |
ee0b3e67 | 498 | struct file *filp = iocb->ki_filp; |
de32ec4c | 499 | struct pipe_inode_info *pipe = filp->private_data; |
1da177e4 LT |
500 | ssize_t ret; |
501 | int do_wakeup; | |
502 | struct iovec *iov = (struct iovec *)_iov; | |
503 | size_t total_len; | |
504 | ssize_t chars; | |
505 | ||
506 | total_len = iov_length(iov, nr_segs); | |
507 | /* Null write succeeds. */ | |
508 | if (unlikely(total_len == 0)) | |
509 | return 0; | |
510 | ||
511 | do_wakeup = 0; | |
512 | ret = 0; | |
ebec73f4 | 513 | __pipe_lock(pipe); |
1da177e4 | 514 | |
923f4f23 | 515 | if (!pipe->readers) { |
1da177e4 LT |
516 | send_sig(SIGPIPE, current, 0); |
517 | ret = -EPIPE; | |
518 | goto out; | |
519 | } | |
520 | ||
521 | /* We try to merge small writes */ | |
522 | chars = total_len & (PAGE_SIZE-1); /* size of the last buffer */ | |
923f4f23 | 523 | if (pipe->nrbufs && chars != 0) { |
341b446b | 524 | int lastbuf = (pipe->curbuf + pipe->nrbufs - 1) & |
35f3d14d | 525 | (pipe->buffers - 1); |
923f4f23 | 526 | struct pipe_buffer *buf = pipe->bufs + lastbuf; |
d4c3cca9 | 527 | const struct pipe_buf_operations *ops = buf->ops; |
1da177e4 | 528 | int offset = buf->offset + buf->len; |
341b446b | 529 | |
1da177e4 | 530 | if (ops->can_merge && offset + chars <= PAGE_SIZE) { |
f6762b7a | 531 | int error, atomic = 1; |
5274f052 | 532 | void *addr; |
5274f052 | 533 | |
cac36bb0 | 534 | error = ops->confirm(pipe, buf); |
f84d7519 | 535 | if (error) |
5274f052 | 536 | goto out; |
f84d7519 | 537 | |
f6762b7a JA |
538 | iov_fault_in_pages_read(iov, chars); |
539 | redo1: | |
540 | addr = ops->map(pipe, buf, atomic); | |
5274f052 | 541 | error = pipe_iov_copy_from_user(offset + addr, iov, |
f6762b7a JA |
542 | chars, atomic); |
543 | ops->unmap(pipe, buf, addr); | |
1da177e4 LT |
544 | ret = error; |
545 | do_wakeup = 1; | |
f6762b7a JA |
546 | if (error) { |
547 | if (atomic) { | |
548 | atomic = 0; | |
549 | goto redo1; | |
550 | } | |
1da177e4 | 551 | goto out; |
f6762b7a | 552 | } |
1da177e4 LT |
553 | buf->len += chars; |
554 | total_len -= chars; | |
555 | ret = chars; | |
556 | if (!total_len) | |
557 | goto out; | |
558 | } | |
559 | } | |
560 | ||
561 | for (;;) { | |
562 | int bufs; | |
341b446b | 563 | |
923f4f23 | 564 | if (!pipe->readers) { |
1da177e4 | 565 | send_sig(SIGPIPE, current, 0); |
341b446b IM |
566 | if (!ret) |
567 | ret = -EPIPE; | |
1da177e4 LT |
568 | break; |
569 | } | |
923f4f23 | 570 | bufs = pipe->nrbufs; |
35f3d14d JA |
571 | if (bufs < pipe->buffers) { |
572 | int newbuf = (pipe->curbuf + bufs) & (pipe->buffers-1); | |
923f4f23 IM |
573 | struct pipe_buffer *buf = pipe->bufs + newbuf; |
574 | struct page *page = pipe->tmp_page; | |
f6762b7a JA |
575 | char *src; |
576 | int error, atomic = 1; | |
1da177e4 LT |
577 | |
578 | if (!page) { | |
579 | page = alloc_page(GFP_HIGHUSER); | |
580 | if (unlikely(!page)) { | |
581 | ret = ret ? : -ENOMEM; | |
582 | break; | |
583 | } | |
923f4f23 | 584 | pipe->tmp_page = page; |
1da177e4 | 585 | } |
341b446b | 586 | /* Always wake up, even if the copy fails. Otherwise |
1da177e4 LT |
587 | * we lock up (O_NONBLOCK-)readers that sleep due to |
588 | * syscall merging. | |
589 | * FIXME! Is this really true? | |
590 | */ | |
591 | do_wakeup = 1; | |
592 | chars = PAGE_SIZE; | |
593 | if (chars > total_len) | |
594 | chars = total_len; | |
595 | ||
f6762b7a JA |
596 | iov_fault_in_pages_read(iov, chars); |
597 | redo2: | |
598 | if (atomic) | |
e8e3c3d6 | 599 | src = kmap_atomic(page); |
f6762b7a JA |
600 | else |
601 | src = kmap(page); | |
602 | ||
603 | error = pipe_iov_copy_from_user(src, iov, chars, | |
604 | atomic); | |
605 | if (atomic) | |
e8e3c3d6 | 606 | kunmap_atomic(src); |
f6762b7a JA |
607 | else |
608 | kunmap(page); | |
609 | ||
1da177e4 | 610 | if (unlikely(error)) { |
f6762b7a JA |
611 | if (atomic) { |
612 | atomic = 0; | |
613 | goto redo2; | |
614 | } | |
341b446b | 615 | if (!ret) |
f6762b7a | 616 | ret = error; |
1da177e4 LT |
617 | break; |
618 | } | |
619 | ret += chars; | |
620 | ||
621 | /* Insert it into the buffer array */ | |
622 | buf->page = page; | |
623 | buf->ops = &anon_pipe_buf_ops; | |
624 | buf->offset = 0; | |
625 | buf->len = chars; | |
9883035a LT |
626 | buf->flags = 0; |
627 | if (is_packetized(filp)) { | |
628 | buf->ops = &packet_pipe_buf_ops; | |
629 | buf->flags = PIPE_BUF_FLAG_PACKET; | |
630 | } | |
923f4f23 IM |
631 | pipe->nrbufs = ++bufs; |
632 | pipe->tmp_page = NULL; | |
1da177e4 LT |
633 | |
634 | total_len -= chars; | |
635 | if (!total_len) | |
636 | break; | |
637 | } | |
35f3d14d | 638 | if (bufs < pipe->buffers) |
1da177e4 LT |
639 | continue; |
640 | if (filp->f_flags & O_NONBLOCK) { | |
341b446b IM |
641 | if (!ret) |
642 | ret = -EAGAIN; | |
1da177e4 LT |
643 | break; |
644 | } | |
645 | if (signal_pending(current)) { | |
341b446b IM |
646 | if (!ret) |
647 | ret = -ERESTARTSYS; | |
1da177e4 LT |
648 | break; |
649 | } | |
650 | if (do_wakeup) { | |
28e58ee8 | 651 | wake_up_interruptible_sync_poll(&pipe->wait, POLLIN | POLLRDNORM); |
923f4f23 | 652 | kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); |
1da177e4 LT |
653 | do_wakeup = 0; |
654 | } | |
923f4f23 IM |
655 | pipe->waiting_writers++; |
656 | pipe_wait(pipe); | |
657 | pipe->waiting_writers--; | |
1da177e4 LT |
658 | } |
659 | out: | |
ebec73f4 | 660 | __pipe_unlock(pipe); |
1da177e4 | 661 | if (do_wakeup) { |
28e58ee8 | 662 | wake_up_interruptible_sync_poll(&pipe->wait, POLLIN | POLLRDNORM); |
923f4f23 | 663 | kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); |
1da177e4 | 664 | } |
c3b2da31 JB |
665 | if (ret > 0) { |
666 | int err = file_update_time(filp); | |
667 | if (err) | |
668 | ret = err; | |
669 | } | |
1da177e4 LT |
670 | return ret; |
671 | } | |
672 | ||
d59d0b1b | 673 | static long pipe_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) |
1da177e4 | 674 | { |
de32ec4c | 675 | struct pipe_inode_info *pipe = filp->private_data; |
1da177e4 LT |
676 | int count, buf, nrbufs; |
677 | ||
678 | switch (cmd) { | |
679 | case FIONREAD: | |
ebec73f4 | 680 | __pipe_lock(pipe); |
1da177e4 | 681 | count = 0; |
923f4f23 IM |
682 | buf = pipe->curbuf; |
683 | nrbufs = pipe->nrbufs; | |
1da177e4 | 684 | while (--nrbufs >= 0) { |
923f4f23 | 685 | count += pipe->bufs[buf].len; |
35f3d14d | 686 | buf = (buf+1) & (pipe->buffers - 1); |
1da177e4 | 687 | } |
ebec73f4 | 688 | __pipe_unlock(pipe); |
923f4f23 | 689 | |
1da177e4 LT |
690 | return put_user(count, (int __user *)arg); |
691 | default: | |
46ce341b | 692 | return -ENOIOCTLCMD; |
1da177e4 LT |
693 | } |
694 | } | |
695 | ||
696 | /* No kernel lock held - fine */ | |
697 | static unsigned int | |
698 | pipe_poll(struct file *filp, poll_table *wait) | |
699 | { | |
700 | unsigned int mask; | |
de32ec4c | 701 | struct pipe_inode_info *pipe = filp->private_data; |
1da177e4 LT |
702 | int nrbufs; |
703 | ||
923f4f23 | 704 | poll_wait(filp, &pipe->wait, wait); |
1da177e4 LT |
705 | |
706 | /* Reading only -- no need for acquiring the semaphore. */ | |
923f4f23 | 707 | nrbufs = pipe->nrbufs; |
1da177e4 LT |
708 | mask = 0; |
709 | if (filp->f_mode & FMODE_READ) { | |
710 | mask = (nrbufs > 0) ? POLLIN | POLLRDNORM : 0; | |
923f4f23 | 711 | if (!pipe->writers && filp->f_version != pipe->w_counter) |
1da177e4 LT |
712 | mask |= POLLHUP; |
713 | } | |
714 | ||
715 | if (filp->f_mode & FMODE_WRITE) { | |
35f3d14d | 716 | mask |= (nrbufs < pipe->buffers) ? POLLOUT | POLLWRNORM : 0; |
5e5d7a22 PE |
717 | /* |
718 | * Most Unices do not set POLLERR for FIFOs but on Linux they | |
719 | * behave exactly like pipes for poll(). | |
720 | */ | |
923f4f23 | 721 | if (!pipe->readers) |
1da177e4 LT |
722 | mask |= POLLERR; |
723 | } | |
724 | ||
725 | return mask; | |
726 | } | |
727 | ||
1da177e4 | 728 | static int |
599a0ac1 | 729 | pipe_release(struct inode *inode, struct file *file) |
1da177e4 | 730 | { |
ba5bb147 AV |
731 | struct pipe_inode_info *pipe = inode->i_pipe; |
732 | int kill = 0; | |
923f4f23 | 733 | |
ebec73f4 | 734 | __pipe_lock(pipe); |
599a0ac1 AV |
735 | if (file->f_mode & FMODE_READ) |
736 | pipe->readers--; | |
737 | if (file->f_mode & FMODE_WRITE) | |
738 | pipe->writers--; | |
341b446b | 739 | |
ba5bb147 | 740 | if (pipe->readers || pipe->writers) { |
28e58ee8 | 741 | wake_up_interruptible_sync_poll(&pipe->wait, POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM | POLLERR | POLLHUP); |
923f4f23 IM |
742 | kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); |
743 | kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); | |
1da177e4 | 744 | } |
ba5bb147 AV |
745 | spin_lock(&inode->i_lock); |
746 | if (!--pipe->files) { | |
747 | inode->i_pipe = NULL; | |
748 | kill = 1; | |
749 | } | |
750 | spin_unlock(&inode->i_lock); | |
ebec73f4 | 751 | __pipe_unlock(pipe); |
ba5bb147 AV |
752 | |
753 | if (kill) | |
4b8a8f1e | 754 | free_pipe_info(pipe); |
1da177e4 LT |
755 | |
756 | return 0; | |
757 | } | |
758 | ||
759 | static int | |
599a0ac1 | 760 | pipe_fasync(int fd, struct file *filp, int on) |
1da177e4 | 761 | { |
de32ec4c | 762 | struct pipe_inode_info *pipe = filp->private_data; |
599a0ac1 | 763 | int retval = 0; |
1da177e4 | 764 | |
ebec73f4 | 765 | __pipe_lock(pipe); |
599a0ac1 AV |
766 | if (filp->f_mode & FMODE_READ) |
767 | retval = fasync_helper(fd, filp, on, &pipe->fasync_readers); | |
768 | if ((filp->f_mode & FMODE_WRITE) && retval >= 0) { | |
341b446b | 769 | retval = fasync_helper(fd, filp, on, &pipe->fasync_writers); |
599a0ac1 AV |
770 | if (retval < 0 && (filp->f_mode & FMODE_READ)) |
771 | /* this can happen only if on == T */ | |
e5bc49ba ON |
772 | fasync_helper(-1, filp, 0, &pipe->fasync_readers); |
773 | } | |
ebec73f4 | 774 | __pipe_unlock(pipe); |
60aa4924 | 775 | return retval; |
1da177e4 LT |
776 | } |
777 | ||
7bee130e | 778 | struct pipe_inode_info *alloc_pipe_info(void) |
3a326a2c | 779 | { |
923f4f23 | 780 | struct pipe_inode_info *pipe; |
3a326a2c | 781 | |
923f4f23 IM |
782 | pipe = kzalloc(sizeof(struct pipe_inode_info), GFP_KERNEL); |
783 | if (pipe) { | |
35f3d14d JA |
784 | pipe->bufs = kzalloc(sizeof(struct pipe_buffer) * PIPE_DEF_BUFFERS, GFP_KERNEL); |
785 | if (pipe->bufs) { | |
786 | init_waitqueue_head(&pipe->wait); | |
787 | pipe->r_counter = pipe->w_counter = 1; | |
35f3d14d | 788 | pipe->buffers = PIPE_DEF_BUFFERS; |
72b0d9aa | 789 | mutex_init(&pipe->mutex); |
35f3d14d JA |
790 | return pipe; |
791 | } | |
792 | kfree(pipe); | |
3a326a2c IM |
793 | } |
794 | ||
35f3d14d | 795 | return NULL; |
3a326a2c IM |
796 | } |
797 | ||
4b8a8f1e | 798 | void free_pipe_info(struct pipe_inode_info *pipe) |
1da177e4 LT |
799 | { |
800 | int i; | |
1da177e4 | 801 | |
35f3d14d | 802 | for (i = 0; i < pipe->buffers; i++) { |
923f4f23 | 803 | struct pipe_buffer *buf = pipe->bufs + i; |
1da177e4 | 804 | if (buf->ops) |
923f4f23 | 805 | buf->ops->release(pipe, buf); |
1da177e4 | 806 | } |
923f4f23 IM |
807 | if (pipe->tmp_page) |
808 | __free_page(pipe->tmp_page); | |
35f3d14d | 809 | kfree(pipe->bufs); |
923f4f23 | 810 | kfree(pipe); |
1da177e4 LT |
811 | } |
812 | ||
fa3536cc | 813 | static struct vfsmount *pipe_mnt __read_mostly; |
341b446b | 814 | |
c23fbb6b ED |
815 | /* |
816 | * pipefs_dname() is called from d_path(). | |
817 | */ | |
818 | static char *pipefs_dname(struct dentry *dentry, char *buffer, int buflen) | |
819 | { | |
820 | return dynamic_dname(dentry, buffer, buflen, "pipe:[%lu]", | |
821 | dentry->d_inode->i_ino); | |
822 | } | |
823 | ||
3ba13d17 | 824 | static const struct dentry_operations pipefs_dentry_operations = { |
c23fbb6b | 825 | .d_dname = pipefs_dname, |
1da177e4 LT |
826 | }; |
827 | ||
828 | static struct inode * get_pipe_inode(void) | |
829 | { | |
a209dfc7 | 830 | struct inode *inode = new_inode_pseudo(pipe_mnt->mnt_sb); |
923f4f23 | 831 | struct pipe_inode_info *pipe; |
1da177e4 LT |
832 | |
833 | if (!inode) | |
834 | goto fail_inode; | |
835 | ||
85fe4025 CH |
836 | inode->i_ino = get_next_ino(); |
837 | ||
7bee130e | 838 | pipe = alloc_pipe_info(); |
923f4f23 | 839 | if (!pipe) |
1da177e4 | 840 | goto fail_iput; |
3a326a2c | 841 | |
ba5bb147 AV |
842 | inode->i_pipe = pipe; |
843 | pipe->files = 2; | |
923f4f23 | 844 | pipe->readers = pipe->writers = 1; |
599a0ac1 | 845 | inode->i_fop = &pipefifo_fops; |
1da177e4 LT |
846 | |
847 | /* | |
848 | * Mark the inode dirty from the very beginning, | |
849 | * that way it will never be moved to the dirty | |
850 | * list because "mark_inode_dirty()" will think | |
851 | * that it already _is_ on the dirty list. | |
852 | */ | |
853 | inode->i_state = I_DIRTY; | |
854 | inode->i_mode = S_IFIFO | S_IRUSR | S_IWUSR; | |
da9592ed DH |
855 | inode->i_uid = current_fsuid(); |
856 | inode->i_gid = current_fsgid(); | |
1da177e4 | 857 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; |
923f4f23 | 858 | |
1da177e4 LT |
859 | return inode; |
860 | ||
861 | fail_iput: | |
862 | iput(inode); | |
341b446b | 863 | |
1da177e4 LT |
864 | fail_inode: |
865 | return NULL; | |
866 | } | |
867 | ||
e4fad8e5 | 868 | int create_pipe_files(struct file **res, int flags) |
1da177e4 | 869 | { |
d6cbd281 | 870 | int err; |
e4fad8e5 | 871 | struct inode *inode = get_pipe_inode(); |
d6cbd281 | 872 | struct file *f; |
2c48b9c4 | 873 | struct path path; |
e4fad8e5 | 874 | static struct qstr name = { .name = "" }; |
1da177e4 | 875 | |
1da177e4 | 876 | if (!inode) |
e4fad8e5 | 877 | return -ENFILE; |
1da177e4 | 878 | |
d6cbd281 | 879 | err = -ENOMEM; |
4b936885 | 880 | path.dentry = d_alloc_pseudo(pipe_mnt->mnt_sb, &name); |
2c48b9c4 | 881 | if (!path.dentry) |
d6cbd281 | 882 | goto err_inode; |
2c48b9c4 | 883 | path.mnt = mntget(pipe_mnt); |
341b446b | 884 | |
2c48b9c4 | 885 | d_instantiate(path.dentry, inode); |
430e285e DH |
886 | |
887 | err = -ENFILE; | |
599a0ac1 | 888 | f = alloc_file(&path, FMODE_WRITE, &pipefifo_fops); |
39b65252 | 889 | if (IS_ERR(f)) |
430e285e | 890 | goto err_dentry; |
341b446b | 891 | |
9883035a | 892 | f->f_flags = O_WRONLY | (flags & (O_NONBLOCK | O_DIRECT)); |
de32ec4c | 893 | f->private_data = inode->i_pipe; |
d6cbd281 | 894 | |
599a0ac1 | 895 | res[0] = alloc_file(&path, FMODE_READ, &pipefifo_fops); |
39b65252 | 896 | if (IS_ERR(res[0])) |
e4fad8e5 AV |
897 | goto err_file; |
898 | ||
899 | path_get(&path); | |
de32ec4c | 900 | res[0]->private_data = inode->i_pipe; |
e4fad8e5 AV |
901 | res[0]->f_flags = O_RDONLY | (flags & O_NONBLOCK); |
902 | res[1] = f; | |
903 | return 0; | |
1da177e4 | 904 | |
e4fad8e5 AV |
905 | err_file: |
906 | put_filp(f); | |
907 | err_dentry: | |
4b8a8f1e | 908 | free_pipe_info(inode->i_pipe); |
2c48b9c4 | 909 | path_put(&path); |
e4fad8e5 | 910 | return err; |
ed152437 | 911 | |
e4fad8e5 | 912 | err_inode: |
4b8a8f1e | 913 | free_pipe_info(inode->i_pipe); |
1da177e4 | 914 | iput(inode); |
e4fad8e5 | 915 | return err; |
d6cbd281 AK |
916 | } |
917 | ||
5b249b1b | 918 | static int __do_pipe_flags(int *fd, struct file **files, int flags) |
d6cbd281 | 919 | { |
d6cbd281 AK |
920 | int error; |
921 | int fdw, fdr; | |
922 | ||
9883035a | 923 | if (flags & ~(O_CLOEXEC | O_NONBLOCK | O_DIRECT)) |
ed8cae8b UD |
924 | return -EINVAL; |
925 | ||
e4fad8e5 AV |
926 | error = create_pipe_files(files, flags); |
927 | if (error) | |
928 | return error; | |
d6cbd281 | 929 | |
ed8cae8b | 930 | error = get_unused_fd_flags(flags); |
d6cbd281 AK |
931 | if (error < 0) |
932 | goto err_read_pipe; | |
933 | fdr = error; | |
934 | ||
ed8cae8b | 935 | error = get_unused_fd_flags(flags); |
d6cbd281 AK |
936 | if (error < 0) |
937 | goto err_fdr; | |
938 | fdw = error; | |
939 | ||
157cf649 | 940 | audit_fd_pair(fdr, fdw); |
d6cbd281 AK |
941 | fd[0] = fdr; |
942 | fd[1] = fdw; | |
d6cbd281 AK |
943 | return 0; |
944 | ||
945 | err_fdr: | |
946 | put_unused_fd(fdr); | |
947 | err_read_pipe: | |
e4fad8e5 AV |
948 | fput(files[0]); |
949 | fput(files[1]); | |
d6cbd281 | 950 | return error; |
1da177e4 LT |
951 | } |
952 | ||
5b249b1b AV |
953 | int do_pipe_flags(int *fd, int flags) |
954 | { | |
955 | struct file *files[2]; | |
956 | int error = __do_pipe_flags(fd, files, flags); | |
957 | if (!error) { | |
958 | fd_install(fd[0], files[0]); | |
959 | fd_install(fd[1], files[1]); | |
960 | } | |
961 | return error; | |
962 | } | |
963 | ||
d35c7b0e UD |
964 | /* |
965 | * sys_pipe() is the normal C calling standard for creating | |
966 | * a pipe. It's not the way Unix traditionally does this, though. | |
967 | */ | |
d4e82042 | 968 | SYSCALL_DEFINE2(pipe2, int __user *, fildes, int, flags) |
d35c7b0e | 969 | { |
5b249b1b | 970 | struct file *files[2]; |
d35c7b0e UD |
971 | int fd[2]; |
972 | int error; | |
973 | ||
5b249b1b | 974 | error = __do_pipe_flags(fd, files, flags); |
d35c7b0e | 975 | if (!error) { |
5b249b1b AV |
976 | if (unlikely(copy_to_user(fildes, fd, sizeof(fd)))) { |
977 | fput(files[0]); | |
978 | fput(files[1]); | |
979 | put_unused_fd(fd[0]); | |
980 | put_unused_fd(fd[1]); | |
d35c7b0e | 981 | error = -EFAULT; |
5b249b1b AV |
982 | } else { |
983 | fd_install(fd[0], files[0]); | |
984 | fd_install(fd[1], files[1]); | |
ba719bae | 985 | } |
d35c7b0e UD |
986 | } |
987 | return error; | |
988 | } | |
989 | ||
2b664219 | 990 | SYSCALL_DEFINE1(pipe, int __user *, fildes) |
ed8cae8b UD |
991 | { |
992 | return sys_pipe2(fildes, 0); | |
993 | } | |
994 | ||
fc7478a2 | 995 | static int wait_for_partner(struct pipe_inode_info *pipe, unsigned int *cnt) |
f776c738 AV |
996 | { |
997 | int cur = *cnt; | |
998 | ||
999 | while (cur == *cnt) { | |
fc7478a2 | 1000 | pipe_wait(pipe); |
f776c738 AV |
1001 | if (signal_pending(current)) |
1002 | break; | |
1003 | } | |
1004 | return cur == *cnt ? -ERESTARTSYS : 0; | |
1005 | } | |
1006 | ||
fc7478a2 | 1007 | static void wake_up_partner(struct pipe_inode_info *pipe) |
f776c738 | 1008 | { |
fc7478a2 | 1009 | wake_up_interruptible(&pipe->wait); |
f776c738 AV |
1010 | } |
1011 | ||
1012 | static int fifo_open(struct inode *inode, struct file *filp) | |
1013 | { | |
1014 | struct pipe_inode_info *pipe; | |
599a0ac1 | 1015 | bool is_pipe = inode->i_sb->s_magic == PIPEFS_MAGIC; |
ba5bb147 | 1016 | int kill = 0; |
f776c738 AV |
1017 | int ret; |
1018 | ||
ba5bb147 AV |
1019 | filp->f_version = 0; |
1020 | ||
1021 | spin_lock(&inode->i_lock); | |
1022 | if (inode->i_pipe) { | |
1023 | pipe = inode->i_pipe; | |
1024 | pipe->files++; | |
1025 | spin_unlock(&inode->i_lock); | |
1026 | } else { | |
1027 | spin_unlock(&inode->i_lock); | |
7bee130e | 1028 | pipe = alloc_pipe_info(); |
f776c738 | 1029 | if (!pipe) |
ba5bb147 AV |
1030 | return -ENOMEM; |
1031 | pipe->files = 1; | |
1032 | spin_lock(&inode->i_lock); | |
1033 | if (unlikely(inode->i_pipe)) { | |
1034 | inode->i_pipe->files++; | |
1035 | spin_unlock(&inode->i_lock); | |
4b8a8f1e | 1036 | free_pipe_info(pipe); |
ba5bb147 AV |
1037 | pipe = inode->i_pipe; |
1038 | } else { | |
1039 | inode->i_pipe = pipe; | |
1040 | spin_unlock(&inode->i_lock); | |
1041 | } | |
f776c738 | 1042 | } |
de32ec4c | 1043 | filp->private_data = pipe; |
ba5bb147 AV |
1044 | /* OK, we have a pipe and it's pinned down */ |
1045 | ||
ebec73f4 | 1046 | __pipe_lock(pipe); |
f776c738 AV |
1047 | |
1048 | /* We can only do regular read/write on fifos */ | |
1049 | filp->f_mode &= (FMODE_READ | FMODE_WRITE); | |
1050 | ||
1051 | switch (filp->f_mode) { | |
1052 | case FMODE_READ: | |
1053 | /* | |
1054 | * O_RDONLY | |
1055 | * POSIX.1 says that O_NONBLOCK means return with the FIFO | |
1056 | * opened, even when there is no process writing the FIFO. | |
1057 | */ | |
f776c738 AV |
1058 | pipe->r_counter++; |
1059 | if (pipe->readers++ == 0) | |
fc7478a2 | 1060 | wake_up_partner(pipe); |
f776c738 | 1061 | |
599a0ac1 | 1062 | if (!is_pipe && !pipe->writers) { |
f776c738 AV |
1063 | if ((filp->f_flags & O_NONBLOCK)) { |
1064 | /* suppress POLLHUP until we have | |
1065 | * seen a writer */ | |
1066 | filp->f_version = pipe->w_counter; | |
1067 | } else { | |
fc7478a2 | 1068 | if (wait_for_partner(pipe, &pipe->w_counter)) |
f776c738 AV |
1069 | goto err_rd; |
1070 | } | |
1071 | } | |
1072 | break; | |
1073 | ||
1074 | case FMODE_WRITE: | |
1075 | /* | |
1076 | * O_WRONLY | |
1077 | * POSIX.1 says that O_NONBLOCK means return -1 with | |
1078 | * errno=ENXIO when there is no process reading the FIFO. | |
1079 | */ | |
1080 | ret = -ENXIO; | |
599a0ac1 | 1081 | if (!is_pipe && (filp->f_flags & O_NONBLOCK) && !pipe->readers) |
f776c738 AV |
1082 | goto err; |
1083 | ||
f776c738 AV |
1084 | pipe->w_counter++; |
1085 | if (!pipe->writers++) | |
fc7478a2 | 1086 | wake_up_partner(pipe); |
f776c738 | 1087 | |
599a0ac1 | 1088 | if (!is_pipe && !pipe->readers) { |
fc7478a2 | 1089 | if (wait_for_partner(pipe, &pipe->r_counter)) |
f776c738 AV |
1090 | goto err_wr; |
1091 | } | |
1092 | break; | |
1093 | ||
1094 | case FMODE_READ | FMODE_WRITE: | |
1095 | /* | |
1096 | * O_RDWR | |
1097 | * POSIX.1 leaves this case "undefined" when O_NONBLOCK is set. | |
1098 | * This implementation will NEVER block on a O_RDWR open, since | |
1099 | * the process can at least talk to itself. | |
1100 | */ | |
f776c738 AV |
1101 | |
1102 | pipe->readers++; | |
1103 | pipe->writers++; | |
1104 | pipe->r_counter++; | |
1105 | pipe->w_counter++; | |
1106 | if (pipe->readers == 1 || pipe->writers == 1) | |
fc7478a2 | 1107 | wake_up_partner(pipe); |
f776c738 AV |
1108 | break; |
1109 | ||
1110 | default: | |
1111 | ret = -EINVAL; | |
1112 | goto err; | |
1113 | } | |
1114 | ||
1115 | /* Ok! */ | |
ebec73f4 | 1116 | __pipe_unlock(pipe); |
f776c738 AV |
1117 | return 0; |
1118 | ||
1119 | err_rd: | |
1120 | if (!--pipe->readers) | |
1121 | wake_up_interruptible(&pipe->wait); | |
1122 | ret = -ERESTARTSYS; | |
1123 | goto err; | |
1124 | ||
1125 | err_wr: | |
1126 | if (!--pipe->writers) | |
1127 | wake_up_interruptible(&pipe->wait); | |
1128 | ret = -ERESTARTSYS; | |
1129 | goto err; | |
1130 | ||
1131 | err: | |
ba5bb147 AV |
1132 | spin_lock(&inode->i_lock); |
1133 | if (!--pipe->files) { | |
1134 | inode->i_pipe = NULL; | |
1135 | kill = 1; | |
1136 | } | |
1137 | spin_unlock(&inode->i_lock); | |
ebec73f4 | 1138 | __pipe_unlock(pipe); |
ba5bb147 | 1139 | if (kill) |
4b8a8f1e | 1140 | free_pipe_info(pipe); |
f776c738 AV |
1141 | return ret; |
1142 | } | |
1143 | ||
599a0ac1 AV |
1144 | const struct file_operations pipefifo_fops = { |
1145 | .open = fifo_open, | |
1146 | .llseek = no_llseek, | |
1147 | .read = do_sync_read, | |
1148 | .aio_read = pipe_read, | |
1149 | .write = do_sync_write, | |
1150 | .aio_write = pipe_write, | |
1151 | .poll = pipe_poll, | |
1152 | .unlocked_ioctl = pipe_ioctl, | |
1153 | .release = pipe_release, | |
1154 | .fasync = pipe_fasync, | |
f776c738 AV |
1155 | }; |
1156 | ||
35f3d14d JA |
1157 | /* |
1158 | * Allocate a new array of pipe buffers and copy the info over. Returns the | |
1159 | * pipe size if successful, or return -ERROR on error. | |
1160 | */ | |
b9598db3 | 1161 | static long pipe_set_size(struct pipe_inode_info *pipe, unsigned long nr_pages) |
35f3d14d JA |
1162 | { |
1163 | struct pipe_buffer *bufs; | |
1164 | ||
35f3d14d JA |
1165 | /* |
1166 | * We can shrink the pipe, if arg >= pipe->nrbufs. Since we don't | |
1167 | * expect a lot of shrink+grow operations, just free and allocate | |
1168 | * again like we would do for growing. If the pipe currently | |
1169 | * contains more buffers than arg, then return busy. | |
1170 | */ | |
b9598db3 | 1171 | if (nr_pages < pipe->nrbufs) |
35f3d14d JA |
1172 | return -EBUSY; |
1173 | ||
2ccd4f4d | 1174 | bufs = kcalloc(nr_pages, sizeof(*bufs), GFP_KERNEL | __GFP_NOWARN); |
35f3d14d JA |
1175 | if (unlikely(!bufs)) |
1176 | return -ENOMEM; | |
1177 | ||
1178 | /* | |
1179 | * The pipe array wraps around, so just start the new one at zero | |
1180 | * and adjust the indexes. | |
1181 | */ | |
1182 | if (pipe->nrbufs) { | |
1d862f41 MS |
1183 | unsigned int tail; |
1184 | unsigned int head; | |
35f3d14d | 1185 | |
1d862f41 MS |
1186 | tail = pipe->curbuf + pipe->nrbufs; |
1187 | if (tail < pipe->buffers) | |
1188 | tail = 0; | |
1189 | else | |
1190 | tail &= (pipe->buffers - 1); | |
1191 | ||
1192 | head = pipe->nrbufs - tail; | |
35f3d14d JA |
1193 | if (head) |
1194 | memcpy(bufs, pipe->bufs + pipe->curbuf, head * sizeof(struct pipe_buffer)); | |
1195 | if (tail) | |
1d862f41 | 1196 | memcpy(bufs + head, pipe->bufs, tail * sizeof(struct pipe_buffer)); |
35f3d14d JA |
1197 | } |
1198 | ||
1199 | pipe->curbuf = 0; | |
1200 | kfree(pipe->bufs); | |
1201 | pipe->bufs = bufs; | |
b9598db3 JA |
1202 | pipe->buffers = nr_pages; |
1203 | return nr_pages * PAGE_SIZE; | |
35f3d14d JA |
1204 | } |
1205 | ||
ff9da691 JA |
1206 | /* |
1207 | * Currently we rely on the pipe array holding a power-of-2 number | |
1208 | * of pages. | |
1209 | */ | |
1210 | static inline unsigned int round_pipe_size(unsigned int size) | |
1211 | { | |
1212 | unsigned long nr_pages; | |
1213 | ||
1214 | nr_pages = (size + PAGE_SIZE - 1) >> PAGE_SHIFT; | |
1215 | return roundup_pow_of_two(nr_pages) << PAGE_SHIFT; | |
1216 | } | |
1217 | ||
1218 | /* | |
1219 | * This should work even if CONFIG_PROC_FS isn't set, as proc_dointvec_minmax | |
1220 | * will return an error. | |
1221 | */ | |
1222 | int pipe_proc_fn(struct ctl_table *table, int write, void __user *buf, | |
1223 | size_t *lenp, loff_t *ppos) | |
1224 | { | |
1225 | int ret; | |
1226 | ||
1227 | ret = proc_dointvec_minmax(table, write, buf, lenp, ppos); | |
1228 | if (ret < 0 || !write) | |
1229 | return ret; | |
1230 | ||
1231 | pipe_max_size = round_pipe_size(pipe_max_size); | |
1232 | return ret; | |
1233 | } | |
1234 | ||
72083646 LT |
1235 | /* |
1236 | * After the inode slimming patch, i_pipe/i_bdev/i_cdev share the same | |
1237 | * location, so checking ->i_pipe is not enough to verify that this is a | |
1238 | * pipe. | |
1239 | */ | |
1240 | struct pipe_inode_info *get_pipe_info(struct file *file) | |
1241 | { | |
de32ec4c | 1242 | return file->f_op == &pipefifo_fops ? file->private_data : NULL; |
72083646 LT |
1243 | } |
1244 | ||
35f3d14d JA |
1245 | long pipe_fcntl(struct file *file, unsigned int cmd, unsigned long arg) |
1246 | { | |
1247 | struct pipe_inode_info *pipe; | |
1248 | long ret; | |
1249 | ||
c66fb347 | 1250 | pipe = get_pipe_info(file); |
35f3d14d JA |
1251 | if (!pipe) |
1252 | return -EBADF; | |
1253 | ||
ebec73f4 | 1254 | __pipe_lock(pipe); |
35f3d14d JA |
1255 | |
1256 | switch (cmd) { | |
b9598db3 | 1257 | case F_SETPIPE_SZ: { |
ff9da691 | 1258 | unsigned int size, nr_pages; |
b9598db3 | 1259 | |
ff9da691 JA |
1260 | size = round_pipe_size(arg); |
1261 | nr_pages = size >> PAGE_SHIFT; | |
b9598db3 | 1262 | |
6db40cf0 MS |
1263 | ret = -EINVAL; |
1264 | if (!nr_pages) | |
1265 | goto out; | |
1266 | ||
ff9da691 | 1267 | if (!capable(CAP_SYS_RESOURCE) && size > pipe_max_size) { |
b4ca7615 | 1268 | ret = -EPERM; |
cc967be5 | 1269 | goto out; |
cc967be5 | 1270 | } |
ff9da691 | 1271 | ret = pipe_set_size(pipe, nr_pages); |
35f3d14d | 1272 | break; |
b9598db3 | 1273 | } |
35f3d14d | 1274 | case F_GETPIPE_SZ: |
b9598db3 | 1275 | ret = pipe->buffers * PAGE_SIZE; |
35f3d14d JA |
1276 | break; |
1277 | default: | |
1278 | ret = -EINVAL; | |
1279 | break; | |
1280 | } | |
1281 | ||
cc967be5 | 1282 | out: |
ebec73f4 | 1283 | __pipe_unlock(pipe); |
35f3d14d JA |
1284 | return ret; |
1285 | } | |
1286 | ||
ff0c7d15 NP |
1287 | static const struct super_operations pipefs_ops = { |
1288 | .destroy_inode = free_inode_nonrcu, | |
d70ef97b | 1289 | .statfs = simple_statfs, |
ff0c7d15 NP |
1290 | }; |
1291 | ||
1da177e4 LT |
1292 | /* |
1293 | * pipefs should _never_ be mounted by userland - too much of security hassle, | |
1294 | * no real gain from having the whole whorehouse mounted. So we don't need | |
1295 | * any operations on the root directory. However, we need a non-trivial | |
1296 | * d_name - pipe: will go nicely and kill the special-casing in procfs. | |
1297 | */ | |
51139ada AV |
1298 | static struct dentry *pipefs_mount(struct file_system_type *fs_type, |
1299 | int flags, const char *dev_name, void *data) | |
1da177e4 | 1300 | { |
c74a1cbb AV |
1301 | return mount_pseudo(fs_type, "pipe:", &pipefs_ops, |
1302 | &pipefs_dentry_operations, PIPEFS_MAGIC); | |
1da177e4 LT |
1303 | } |
1304 | ||
1305 | static struct file_system_type pipe_fs_type = { | |
1306 | .name = "pipefs", | |
51139ada | 1307 | .mount = pipefs_mount, |
1da177e4 LT |
1308 | .kill_sb = kill_anon_super, |
1309 | }; | |
1310 | ||
1311 | static int __init init_pipe_fs(void) | |
1312 | { | |
1313 | int err = register_filesystem(&pipe_fs_type); | |
341b446b | 1314 | |
1da177e4 LT |
1315 | if (!err) { |
1316 | pipe_mnt = kern_mount(&pipe_fs_type); | |
1317 | if (IS_ERR(pipe_mnt)) { | |
1318 | err = PTR_ERR(pipe_mnt); | |
1319 | unregister_filesystem(&pipe_fs_type); | |
1320 | } | |
1321 | } | |
1322 | return err; | |
1323 | } | |
1324 | ||
1da177e4 | 1325 | fs_initcall(init_pipe_fs); |