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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 LT |
15 | #include <linux/mount.h> |
16 | #include <linux/pipe_fs_i.h> | |
17 | #include <linux/uio.h> | |
18 | #include <linux/highmem.h> | |
5274f052 | 19 | #include <linux/pagemap.h> |
db349509 | 20 | #include <linux/audit.h> |
ba719bae | 21 | #include <linux/syscalls.h> |
1da177e4 LT |
22 | |
23 | #include <asm/uaccess.h> | |
24 | #include <asm/ioctls.h> | |
25 | ||
26 | /* | |
27 | * We use a start+len construction, which provides full use of the | |
28 | * allocated memory. | |
29 | * -- Florian Coosmann (FGC) | |
30 | * | |
31 | * Reads with count = 0 should always return 0. | |
32 | * -- Julian Bradfield 1999-06-07. | |
33 | * | |
34 | * FIFOs and Pipes now generate SIGIO for both readers and writers. | |
35 | * -- Jeremy Elson <jelson@circlemud.org> 2001-08-16 | |
36 | * | |
37 | * pipe_read & write cleanup | |
38 | * -- Manfred Spraul <manfred@colorfullife.com> 2002-05-09 | |
39 | */ | |
40 | ||
61e0d47c MS |
41 | static void pipe_lock_nested(struct pipe_inode_info *pipe, int subclass) |
42 | { | |
43 | if (pipe->inode) | |
44 | mutex_lock_nested(&pipe->inode->i_mutex, subclass); | |
45 | } | |
46 | ||
47 | void pipe_lock(struct pipe_inode_info *pipe) | |
48 | { | |
49 | /* | |
50 | * pipe_lock() nests non-pipe inode locks (for writing to a file) | |
51 | */ | |
52 | pipe_lock_nested(pipe, I_MUTEX_PARENT); | |
53 | } | |
54 | EXPORT_SYMBOL(pipe_lock); | |
55 | ||
56 | void pipe_unlock(struct pipe_inode_info *pipe) | |
57 | { | |
58 | if (pipe->inode) | |
59 | mutex_unlock(&pipe->inode->i_mutex); | |
60 | } | |
61 | EXPORT_SYMBOL(pipe_unlock); | |
62 | ||
63 | void pipe_double_lock(struct pipe_inode_info *pipe1, | |
64 | struct pipe_inode_info *pipe2) | |
65 | { | |
66 | BUG_ON(pipe1 == pipe2); | |
67 | ||
68 | if (pipe1 < pipe2) { | |
69 | pipe_lock_nested(pipe1, I_MUTEX_PARENT); | |
70 | pipe_lock_nested(pipe2, I_MUTEX_CHILD); | |
71 | } else { | |
023d43c7 PZ |
72 | pipe_lock_nested(pipe2, I_MUTEX_PARENT); |
73 | pipe_lock_nested(pipe1, I_MUTEX_CHILD); | |
61e0d47c MS |
74 | } |
75 | } | |
76 | ||
1da177e4 | 77 | /* Drop the inode semaphore and wait for a pipe event, atomically */ |
3a326a2c | 78 | void pipe_wait(struct pipe_inode_info *pipe) |
1da177e4 LT |
79 | { |
80 | DEFINE_WAIT(wait); | |
81 | ||
d79fc0fc IM |
82 | /* |
83 | * Pipes are system-local resources, so sleeping on them | |
84 | * is considered a noninteractive wait: | |
85 | */ | |
af927232 | 86 | prepare_to_wait(&pipe->wait, &wait, TASK_INTERRUPTIBLE); |
61e0d47c | 87 | pipe_unlock(pipe); |
1da177e4 | 88 | schedule(); |
3a326a2c | 89 | finish_wait(&pipe->wait, &wait); |
61e0d47c | 90 | pipe_lock(pipe); |
1da177e4 LT |
91 | } |
92 | ||
858119e1 | 93 | static int |
f6762b7a JA |
94 | pipe_iov_copy_from_user(void *to, struct iovec *iov, unsigned long len, |
95 | int atomic) | |
1da177e4 LT |
96 | { |
97 | unsigned long copy; | |
98 | ||
99 | while (len > 0) { | |
100 | while (!iov->iov_len) | |
101 | iov++; | |
102 | copy = min_t(unsigned long, len, iov->iov_len); | |
103 | ||
f6762b7a JA |
104 | if (atomic) { |
105 | if (__copy_from_user_inatomic(to, iov->iov_base, copy)) | |
106 | return -EFAULT; | |
107 | } else { | |
108 | if (copy_from_user(to, iov->iov_base, copy)) | |
109 | return -EFAULT; | |
110 | } | |
1da177e4 LT |
111 | to += copy; |
112 | len -= copy; | |
113 | iov->iov_base += copy; | |
114 | iov->iov_len -= copy; | |
115 | } | |
116 | return 0; | |
117 | } | |
118 | ||
858119e1 | 119 | static int |
f6762b7a JA |
120 | pipe_iov_copy_to_user(struct iovec *iov, const void *from, 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_to_user_inatomic(iov->iov_base, from, copy)) | |
132 | return -EFAULT; | |
133 | } else { | |
134 | if (copy_to_user(iov->iov_base, from, copy)) | |
135 | return -EFAULT; | |
136 | } | |
1da177e4 LT |
137 | from += copy; |
138 | len -= copy; | |
139 | iov->iov_base += copy; | |
140 | iov->iov_len -= copy; | |
141 | } | |
142 | return 0; | |
143 | } | |
144 | ||
f6762b7a JA |
145 | /* |
146 | * Attempt to pre-fault in the user memory, so we can use atomic copies. | |
147 | * Returns the number of bytes not faulted in. | |
148 | */ | |
149 | static int iov_fault_in_pages_write(struct iovec *iov, unsigned long len) | |
150 | { | |
151 | while (!iov->iov_len) | |
152 | iov++; | |
153 | ||
154 | while (len > 0) { | |
155 | unsigned long this_len; | |
156 | ||
157 | this_len = min_t(unsigned long, len, iov->iov_len); | |
158 | if (fault_in_pages_writeable(iov->iov_base, this_len)) | |
159 | break; | |
160 | ||
161 | len -= this_len; | |
162 | iov++; | |
163 | } | |
164 | ||
165 | return len; | |
166 | } | |
167 | ||
168 | /* | |
169 | * Pre-fault in the user memory, so we can use atomic copies. | |
170 | */ | |
171 | static void iov_fault_in_pages_read(struct iovec *iov, unsigned long len) | |
172 | { | |
173 | while (!iov->iov_len) | |
174 | iov++; | |
175 | ||
176 | while (len > 0) { | |
177 | unsigned long this_len; | |
178 | ||
179 | this_len = min_t(unsigned long, len, iov->iov_len); | |
180 | fault_in_pages_readable(iov->iov_base, this_len); | |
181 | len -= this_len; | |
182 | iov++; | |
183 | } | |
184 | } | |
185 | ||
341b446b IM |
186 | static void anon_pipe_buf_release(struct pipe_inode_info *pipe, |
187 | struct pipe_buffer *buf) | |
1da177e4 LT |
188 | { |
189 | struct page *page = buf->page; | |
190 | ||
5274f052 JA |
191 | /* |
192 | * If nobody else uses this page, and we don't already have a | |
193 | * temporary page, let's keep track of it as a one-deep | |
341b446b | 194 | * allocation cache. (Otherwise just release our reference to it) |
5274f052 | 195 | */ |
341b446b | 196 | if (page_count(page) == 1 && !pipe->tmp_page) |
923f4f23 | 197 | pipe->tmp_page = page; |
341b446b IM |
198 | else |
199 | page_cache_release(page); | |
1da177e4 LT |
200 | } |
201 | ||
0845718d JA |
202 | /** |
203 | * generic_pipe_buf_map - virtually map a pipe buffer | |
204 | * @pipe: the pipe that the buffer belongs to | |
205 | * @buf: the buffer that should be mapped | |
206 | * @atomic: whether to use an atomic map | |
207 | * | |
208 | * Description: | |
209 | * This function returns a kernel virtual address mapping for the | |
b51d63c6 | 210 | * pipe_buffer passed in @buf. If @atomic is set, an atomic map is provided |
0845718d JA |
211 | * and the caller has to be careful not to fault before calling |
212 | * the unmap function. | |
213 | * | |
214 | * Note that this function occupies KM_USER0 if @atomic != 0. | |
215 | */ | |
f84d7519 | 216 | void *generic_pipe_buf_map(struct pipe_inode_info *pipe, |
f6762b7a | 217 | struct pipe_buffer *buf, int atomic) |
1da177e4 | 218 | { |
f6762b7a JA |
219 | if (atomic) { |
220 | buf->flags |= PIPE_BUF_FLAG_ATOMIC; | |
221 | return kmap_atomic(buf->page, KM_USER0); | |
222 | } | |
223 | ||
1da177e4 LT |
224 | return kmap(buf->page); |
225 | } | |
226 | ||
0845718d JA |
227 | /** |
228 | * generic_pipe_buf_unmap - unmap a previously mapped pipe buffer | |
229 | * @pipe: the pipe that the buffer belongs to | |
230 | * @buf: the buffer that should be unmapped | |
231 | * @map_data: the data that the mapping function returned | |
232 | * | |
233 | * Description: | |
234 | * This function undoes the mapping that ->map() provided. | |
235 | */ | |
f84d7519 | 236 | void generic_pipe_buf_unmap(struct pipe_inode_info *pipe, |
f6762b7a | 237 | struct pipe_buffer *buf, void *map_data) |
1da177e4 | 238 | { |
f6762b7a JA |
239 | if (buf->flags & PIPE_BUF_FLAG_ATOMIC) { |
240 | buf->flags &= ~PIPE_BUF_FLAG_ATOMIC; | |
241 | kunmap_atomic(map_data, KM_USER0); | |
242 | } else | |
243 | kunmap(buf->page); | |
1da177e4 LT |
244 | } |
245 | ||
0845718d | 246 | /** |
b51d63c6 | 247 | * generic_pipe_buf_steal - attempt to take ownership of a &pipe_buffer |
0845718d JA |
248 | * @pipe: the pipe that the buffer belongs to |
249 | * @buf: the buffer to attempt to steal | |
250 | * | |
251 | * Description: | |
b51d63c6 | 252 | * This function attempts to steal the &struct page attached to |
0845718d JA |
253 | * @buf. If successful, this function returns 0 and returns with |
254 | * the page locked. The caller may then reuse the page for whatever | |
b51d63c6 | 255 | * he wishes; the typical use is insertion into a different file |
0845718d JA |
256 | * page cache. |
257 | */ | |
330ab716 JA |
258 | int generic_pipe_buf_steal(struct pipe_inode_info *pipe, |
259 | struct pipe_buffer *buf) | |
5abc97aa | 260 | { |
46e678c9 JA |
261 | struct page *page = buf->page; |
262 | ||
0845718d JA |
263 | /* |
264 | * A reference of one is golden, that means that the owner of this | |
265 | * page is the only one holding a reference to it. lock the page | |
266 | * and return OK. | |
267 | */ | |
46e678c9 | 268 | if (page_count(page) == 1) { |
46e678c9 JA |
269 | lock_page(page); |
270 | return 0; | |
271 | } | |
272 | ||
273 | return 1; | |
5abc97aa JA |
274 | } |
275 | ||
0845718d | 276 | /** |
b51d63c6 | 277 | * generic_pipe_buf_get - get a reference to a &struct pipe_buffer |
0845718d JA |
278 | * @pipe: the pipe that the buffer belongs to |
279 | * @buf: the buffer to get a reference to | |
280 | * | |
281 | * Description: | |
282 | * This function grabs an extra reference to @buf. It's used in | |
283 | * in the tee() system call, when we duplicate the buffers in one | |
284 | * pipe into another. | |
285 | */ | |
286 | void generic_pipe_buf_get(struct pipe_inode_info *pipe, struct pipe_buffer *buf) | |
70524490 JA |
287 | { |
288 | page_cache_get(buf->page); | |
289 | } | |
290 | ||
0845718d JA |
291 | /** |
292 | * generic_pipe_buf_confirm - verify contents of the pipe buffer | |
79685b8d | 293 | * @info: the pipe that the buffer belongs to |
0845718d JA |
294 | * @buf: the buffer to confirm |
295 | * | |
296 | * Description: | |
297 | * This function does nothing, because the generic pipe code uses | |
298 | * pages that are always good when inserted into the pipe. | |
299 | */ | |
cac36bb0 JA |
300 | int generic_pipe_buf_confirm(struct pipe_inode_info *info, |
301 | struct pipe_buffer *buf) | |
f84d7519 JA |
302 | { |
303 | return 0; | |
304 | } | |
305 | ||
6818173b MS |
306 | /** |
307 | * generic_pipe_buf_release - put a reference to a &struct pipe_buffer | |
308 | * @pipe: the pipe that the buffer belongs to | |
309 | * @buf: the buffer to put a reference to | |
310 | * | |
311 | * Description: | |
312 | * This function releases a reference to @buf. | |
313 | */ | |
314 | void generic_pipe_buf_release(struct pipe_inode_info *pipe, | |
315 | struct pipe_buffer *buf) | |
316 | { | |
317 | page_cache_release(buf->page); | |
318 | } | |
319 | ||
d4c3cca9 | 320 | static const struct pipe_buf_operations anon_pipe_buf_ops = { |
1da177e4 | 321 | .can_merge = 1, |
f84d7519 JA |
322 | .map = generic_pipe_buf_map, |
323 | .unmap = generic_pipe_buf_unmap, | |
cac36bb0 | 324 | .confirm = generic_pipe_buf_confirm, |
1da177e4 | 325 | .release = anon_pipe_buf_release, |
330ab716 | 326 | .steal = generic_pipe_buf_steal, |
f84d7519 | 327 | .get = generic_pipe_buf_get, |
1da177e4 LT |
328 | }; |
329 | ||
330 | static ssize_t | |
ee0b3e67 BP |
331 | pipe_read(struct kiocb *iocb, const struct iovec *_iov, |
332 | unsigned long nr_segs, loff_t pos) | |
1da177e4 | 333 | { |
ee0b3e67 | 334 | struct file *filp = iocb->ki_filp; |
0f7fc9e4 | 335 | struct inode *inode = filp->f_path.dentry->d_inode; |
923f4f23 | 336 | struct pipe_inode_info *pipe; |
1da177e4 LT |
337 | int do_wakeup; |
338 | ssize_t ret; | |
339 | struct iovec *iov = (struct iovec *)_iov; | |
340 | size_t total_len; | |
341 | ||
342 | total_len = iov_length(iov, nr_segs); | |
343 | /* Null read succeeds. */ | |
344 | if (unlikely(total_len == 0)) | |
345 | return 0; | |
346 | ||
347 | do_wakeup = 0; | |
348 | ret = 0; | |
9aeedfc4 | 349 | mutex_lock(&inode->i_mutex); |
923f4f23 | 350 | pipe = inode->i_pipe; |
1da177e4 | 351 | for (;;) { |
923f4f23 | 352 | int bufs = pipe->nrbufs; |
1da177e4 | 353 | if (bufs) { |
923f4f23 IM |
354 | int curbuf = pipe->curbuf; |
355 | struct pipe_buffer *buf = pipe->bufs + curbuf; | |
d4c3cca9 | 356 | const struct pipe_buf_operations *ops = buf->ops; |
1da177e4 LT |
357 | void *addr; |
358 | size_t chars = buf->len; | |
f6762b7a | 359 | int error, atomic; |
1da177e4 LT |
360 | |
361 | if (chars > total_len) | |
362 | chars = total_len; | |
363 | ||
cac36bb0 | 364 | error = ops->confirm(pipe, buf); |
f84d7519 | 365 | if (error) { |
5274f052 | 366 | if (!ret) |
f84d7519 | 367 | error = ret; |
5274f052 JA |
368 | break; |
369 | } | |
f84d7519 | 370 | |
f6762b7a JA |
371 | atomic = !iov_fault_in_pages_write(iov, chars); |
372 | redo: | |
373 | addr = ops->map(pipe, buf, atomic); | |
374 | error = pipe_iov_copy_to_user(iov, addr + buf->offset, chars, atomic); | |
375 | ops->unmap(pipe, buf, addr); | |
1da177e4 | 376 | if (unlikely(error)) { |
f6762b7a JA |
377 | /* |
378 | * Just retry with the slow path if we failed. | |
379 | */ | |
380 | if (atomic) { | |
381 | atomic = 0; | |
382 | goto redo; | |
383 | } | |
341b446b | 384 | if (!ret) |
f6762b7a | 385 | ret = error; |
1da177e4 LT |
386 | break; |
387 | } | |
388 | ret += chars; | |
389 | buf->offset += chars; | |
390 | buf->len -= chars; | |
391 | if (!buf->len) { | |
392 | buf->ops = NULL; | |
923f4f23 | 393 | ops->release(pipe, buf); |
35f3d14d | 394 | curbuf = (curbuf + 1) & (pipe->buffers - 1); |
923f4f23 IM |
395 | pipe->curbuf = curbuf; |
396 | pipe->nrbufs = --bufs; | |
1da177e4 LT |
397 | do_wakeup = 1; |
398 | } | |
399 | total_len -= chars; | |
400 | if (!total_len) | |
401 | break; /* common path: read succeeded */ | |
402 | } | |
403 | if (bufs) /* More to do? */ | |
404 | continue; | |
923f4f23 | 405 | if (!pipe->writers) |
1da177e4 | 406 | break; |
923f4f23 | 407 | if (!pipe->waiting_writers) { |
1da177e4 LT |
408 | /* syscall merging: Usually we must not sleep |
409 | * if O_NONBLOCK is set, or if we got some data. | |
410 | * But if a writer sleeps in kernel space, then | |
411 | * we can wait for that data without violating POSIX. | |
412 | */ | |
413 | if (ret) | |
414 | break; | |
415 | if (filp->f_flags & O_NONBLOCK) { | |
416 | ret = -EAGAIN; | |
417 | break; | |
418 | } | |
419 | } | |
420 | if (signal_pending(current)) { | |
341b446b IM |
421 | if (!ret) |
422 | ret = -ERESTARTSYS; | |
1da177e4 LT |
423 | break; |
424 | } | |
425 | if (do_wakeup) { | |
923f4f23 IM |
426 | wake_up_interruptible_sync(&pipe->wait); |
427 | kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); | |
1da177e4 | 428 | } |
923f4f23 | 429 | pipe_wait(pipe); |
1da177e4 | 430 | } |
9aeedfc4 | 431 | mutex_unlock(&inode->i_mutex); |
341b446b IM |
432 | |
433 | /* Signal writers asynchronously that there is more room. */ | |
1da177e4 | 434 | if (do_wakeup) { |
71e20f18 | 435 | wake_up_interruptible_sync(&pipe->wait); |
923f4f23 | 436 | kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); |
1da177e4 LT |
437 | } |
438 | if (ret > 0) | |
439 | file_accessed(filp); | |
440 | return ret; | |
441 | } | |
442 | ||
443 | static ssize_t | |
ee0b3e67 BP |
444 | pipe_write(struct kiocb *iocb, const struct iovec *_iov, |
445 | unsigned long nr_segs, loff_t ppos) | |
1da177e4 | 446 | { |
ee0b3e67 | 447 | struct file *filp = iocb->ki_filp; |
0f7fc9e4 | 448 | struct inode *inode = filp->f_path.dentry->d_inode; |
923f4f23 | 449 | struct pipe_inode_info *pipe; |
1da177e4 LT |
450 | ssize_t ret; |
451 | int do_wakeup; | |
452 | struct iovec *iov = (struct iovec *)_iov; | |
453 | size_t total_len; | |
454 | ssize_t chars; | |
455 | ||
456 | total_len = iov_length(iov, nr_segs); | |
457 | /* Null write succeeds. */ | |
458 | if (unlikely(total_len == 0)) | |
459 | return 0; | |
460 | ||
461 | do_wakeup = 0; | |
462 | ret = 0; | |
9aeedfc4 | 463 | mutex_lock(&inode->i_mutex); |
923f4f23 | 464 | pipe = inode->i_pipe; |
1da177e4 | 465 | |
923f4f23 | 466 | if (!pipe->readers) { |
1da177e4 LT |
467 | send_sig(SIGPIPE, current, 0); |
468 | ret = -EPIPE; | |
469 | goto out; | |
470 | } | |
471 | ||
472 | /* We try to merge small writes */ | |
473 | chars = total_len & (PAGE_SIZE-1); /* size of the last buffer */ | |
923f4f23 | 474 | if (pipe->nrbufs && chars != 0) { |
341b446b | 475 | int lastbuf = (pipe->curbuf + pipe->nrbufs - 1) & |
35f3d14d | 476 | (pipe->buffers - 1); |
923f4f23 | 477 | struct pipe_buffer *buf = pipe->bufs + lastbuf; |
d4c3cca9 | 478 | const struct pipe_buf_operations *ops = buf->ops; |
1da177e4 | 479 | int offset = buf->offset + buf->len; |
341b446b | 480 | |
1da177e4 | 481 | if (ops->can_merge && offset + chars <= PAGE_SIZE) { |
f6762b7a | 482 | int error, atomic = 1; |
5274f052 | 483 | void *addr; |
5274f052 | 484 | |
cac36bb0 | 485 | error = ops->confirm(pipe, buf); |
f84d7519 | 486 | if (error) |
5274f052 | 487 | goto out; |
f84d7519 | 488 | |
f6762b7a JA |
489 | iov_fault_in_pages_read(iov, chars); |
490 | redo1: | |
491 | addr = ops->map(pipe, buf, atomic); | |
5274f052 | 492 | error = pipe_iov_copy_from_user(offset + addr, iov, |
f6762b7a JA |
493 | chars, atomic); |
494 | ops->unmap(pipe, buf, addr); | |
1da177e4 LT |
495 | ret = error; |
496 | do_wakeup = 1; | |
f6762b7a JA |
497 | if (error) { |
498 | if (atomic) { | |
499 | atomic = 0; | |
500 | goto redo1; | |
501 | } | |
1da177e4 | 502 | goto out; |
f6762b7a | 503 | } |
1da177e4 LT |
504 | buf->len += chars; |
505 | total_len -= chars; | |
506 | ret = chars; | |
507 | if (!total_len) | |
508 | goto out; | |
509 | } | |
510 | } | |
511 | ||
512 | for (;;) { | |
513 | int bufs; | |
341b446b | 514 | |
923f4f23 | 515 | if (!pipe->readers) { |
1da177e4 | 516 | send_sig(SIGPIPE, current, 0); |
341b446b IM |
517 | if (!ret) |
518 | ret = -EPIPE; | |
1da177e4 LT |
519 | break; |
520 | } | |
923f4f23 | 521 | bufs = pipe->nrbufs; |
35f3d14d JA |
522 | if (bufs < pipe->buffers) { |
523 | int newbuf = (pipe->curbuf + bufs) & (pipe->buffers-1); | |
923f4f23 IM |
524 | struct pipe_buffer *buf = pipe->bufs + newbuf; |
525 | struct page *page = pipe->tmp_page; | |
f6762b7a JA |
526 | char *src; |
527 | int error, atomic = 1; | |
1da177e4 LT |
528 | |
529 | if (!page) { | |
530 | page = alloc_page(GFP_HIGHUSER); | |
531 | if (unlikely(!page)) { | |
532 | ret = ret ? : -ENOMEM; | |
533 | break; | |
534 | } | |
923f4f23 | 535 | pipe->tmp_page = page; |
1da177e4 | 536 | } |
341b446b | 537 | /* Always wake up, even if the copy fails. Otherwise |
1da177e4 LT |
538 | * we lock up (O_NONBLOCK-)readers that sleep due to |
539 | * syscall merging. | |
540 | * FIXME! Is this really true? | |
541 | */ | |
542 | do_wakeup = 1; | |
543 | chars = PAGE_SIZE; | |
544 | if (chars > total_len) | |
545 | chars = total_len; | |
546 | ||
f6762b7a JA |
547 | iov_fault_in_pages_read(iov, chars); |
548 | redo2: | |
549 | if (atomic) | |
550 | src = kmap_atomic(page, KM_USER0); | |
551 | else | |
552 | src = kmap(page); | |
553 | ||
554 | error = pipe_iov_copy_from_user(src, iov, chars, | |
555 | atomic); | |
556 | if (atomic) | |
557 | kunmap_atomic(src, KM_USER0); | |
558 | else | |
559 | kunmap(page); | |
560 | ||
1da177e4 | 561 | if (unlikely(error)) { |
f6762b7a JA |
562 | if (atomic) { |
563 | atomic = 0; | |
564 | goto redo2; | |
565 | } | |
341b446b | 566 | if (!ret) |
f6762b7a | 567 | ret = error; |
1da177e4 LT |
568 | break; |
569 | } | |
570 | ret += chars; | |
571 | ||
572 | /* Insert it into the buffer array */ | |
573 | buf->page = page; | |
574 | buf->ops = &anon_pipe_buf_ops; | |
575 | buf->offset = 0; | |
576 | buf->len = chars; | |
923f4f23 IM |
577 | pipe->nrbufs = ++bufs; |
578 | pipe->tmp_page = NULL; | |
1da177e4 LT |
579 | |
580 | total_len -= chars; | |
581 | if (!total_len) | |
582 | break; | |
583 | } | |
35f3d14d | 584 | if (bufs < pipe->buffers) |
1da177e4 LT |
585 | continue; |
586 | if (filp->f_flags & O_NONBLOCK) { | |
341b446b IM |
587 | if (!ret) |
588 | ret = -EAGAIN; | |
1da177e4 LT |
589 | break; |
590 | } | |
591 | if (signal_pending(current)) { | |
341b446b IM |
592 | if (!ret) |
593 | ret = -ERESTARTSYS; | |
1da177e4 LT |
594 | break; |
595 | } | |
596 | if (do_wakeup) { | |
923f4f23 IM |
597 | wake_up_interruptible_sync(&pipe->wait); |
598 | kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); | |
1da177e4 LT |
599 | do_wakeup = 0; |
600 | } | |
923f4f23 IM |
601 | pipe->waiting_writers++; |
602 | pipe_wait(pipe); | |
603 | pipe->waiting_writers--; | |
1da177e4 LT |
604 | } |
605 | out: | |
9aeedfc4 | 606 | mutex_unlock(&inode->i_mutex); |
1da177e4 | 607 | if (do_wakeup) { |
71e20f18 | 608 | wake_up_interruptible_sync(&pipe->wait); |
923f4f23 | 609 | kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); |
1da177e4 LT |
610 | } |
611 | if (ret > 0) | |
870f4817 | 612 | file_update_time(filp); |
1da177e4 LT |
613 | return ret; |
614 | } | |
615 | ||
1da177e4 LT |
616 | static ssize_t |
617 | bad_pipe_r(struct file *filp, char __user *buf, size_t count, loff_t *ppos) | |
618 | { | |
619 | return -EBADF; | |
620 | } | |
621 | ||
622 | static ssize_t | |
341b446b IM |
623 | bad_pipe_w(struct file *filp, const char __user *buf, size_t count, |
624 | loff_t *ppos) | |
1da177e4 LT |
625 | { |
626 | return -EBADF; | |
627 | } | |
628 | ||
d59d0b1b | 629 | static long pipe_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) |
1da177e4 | 630 | { |
0f7fc9e4 | 631 | struct inode *inode = filp->f_path.dentry->d_inode; |
923f4f23 | 632 | struct pipe_inode_info *pipe; |
1da177e4 LT |
633 | int count, buf, nrbufs; |
634 | ||
635 | switch (cmd) { | |
636 | case FIONREAD: | |
9aeedfc4 | 637 | mutex_lock(&inode->i_mutex); |
923f4f23 | 638 | pipe = inode->i_pipe; |
1da177e4 | 639 | count = 0; |
923f4f23 IM |
640 | buf = pipe->curbuf; |
641 | nrbufs = pipe->nrbufs; | |
1da177e4 | 642 | while (--nrbufs >= 0) { |
923f4f23 | 643 | count += pipe->bufs[buf].len; |
35f3d14d | 644 | buf = (buf+1) & (pipe->buffers - 1); |
1da177e4 | 645 | } |
9aeedfc4 | 646 | mutex_unlock(&inode->i_mutex); |
923f4f23 | 647 | |
1da177e4 LT |
648 | return put_user(count, (int __user *)arg); |
649 | default: | |
650 | return -EINVAL; | |
651 | } | |
652 | } | |
653 | ||
654 | /* No kernel lock held - fine */ | |
655 | static unsigned int | |
656 | pipe_poll(struct file *filp, poll_table *wait) | |
657 | { | |
658 | unsigned int mask; | |
0f7fc9e4 | 659 | struct inode *inode = filp->f_path.dentry->d_inode; |
923f4f23 | 660 | struct pipe_inode_info *pipe = inode->i_pipe; |
1da177e4 LT |
661 | int nrbufs; |
662 | ||
923f4f23 | 663 | poll_wait(filp, &pipe->wait, wait); |
1da177e4 LT |
664 | |
665 | /* Reading only -- no need for acquiring the semaphore. */ | |
923f4f23 | 666 | nrbufs = pipe->nrbufs; |
1da177e4 LT |
667 | mask = 0; |
668 | if (filp->f_mode & FMODE_READ) { | |
669 | mask = (nrbufs > 0) ? POLLIN | POLLRDNORM : 0; | |
923f4f23 | 670 | if (!pipe->writers && filp->f_version != pipe->w_counter) |
1da177e4 LT |
671 | mask |= POLLHUP; |
672 | } | |
673 | ||
674 | if (filp->f_mode & FMODE_WRITE) { | |
35f3d14d | 675 | mask |= (nrbufs < pipe->buffers) ? POLLOUT | POLLWRNORM : 0; |
5e5d7a22 PE |
676 | /* |
677 | * Most Unices do not set POLLERR for FIFOs but on Linux they | |
678 | * behave exactly like pipes for poll(). | |
679 | */ | |
923f4f23 | 680 | if (!pipe->readers) |
1da177e4 LT |
681 | mask |= POLLERR; |
682 | } | |
683 | ||
684 | return mask; | |
685 | } | |
686 | ||
1da177e4 LT |
687 | static int |
688 | pipe_release(struct inode *inode, int decr, int decw) | |
689 | { | |
923f4f23 IM |
690 | struct pipe_inode_info *pipe; |
691 | ||
9aeedfc4 | 692 | mutex_lock(&inode->i_mutex); |
923f4f23 IM |
693 | pipe = inode->i_pipe; |
694 | pipe->readers -= decr; | |
695 | pipe->writers -= decw; | |
341b446b | 696 | |
923f4f23 | 697 | if (!pipe->readers && !pipe->writers) { |
1da177e4 LT |
698 | free_pipe_info(inode); |
699 | } else { | |
71e20f18 | 700 | wake_up_interruptible_sync(&pipe->wait); |
923f4f23 IM |
701 | kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); |
702 | kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); | |
1da177e4 | 703 | } |
9aeedfc4 | 704 | mutex_unlock(&inode->i_mutex); |
1da177e4 LT |
705 | |
706 | return 0; | |
707 | } | |
708 | ||
709 | static int | |
710 | pipe_read_fasync(int fd, struct file *filp, int on) | |
711 | { | |
0f7fc9e4 | 712 | struct inode *inode = filp->f_path.dentry->d_inode; |
1da177e4 LT |
713 | int retval; |
714 | ||
9aeedfc4 IM |
715 | mutex_lock(&inode->i_mutex); |
716 | retval = fasync_helper(fd, filp, on, &inode->i_pipe->fasync_readers); | |
717 | mutex_unlock(&inode->i_mutex); | |
1da177e4 | 718 | |
60aa4924 | 719 | return retval; |
1da177e4 LT |
720 | } |
721 | ||
722 | ||
723 | static int | |
724 | pipe_write_fasync(int fd, struct file *filp, int on) | |
725 | { | |
0f7fc9e4 | 726 | struct inode *inode = filp->f_path.dentry->d_inode; |
1da177e4 LT |
727 | int retval; |
728 | ||
9aeedfc4 IM |
729 | mutex_lock(&inode->i_mutex); |
730 | retval = fasync_helper(fd, filp, on, &inode->i_pipe->fasync_writers); | |
731 | mutex_unlock(&inode->i_mutex); | |
1da177e4 | 732 | |
60aa4924 | 733 | return retval; |
1da177e4 LT |
734 | } |
735 | ||
736 | ||
737 | static int | |
738 | pipe_rdwr_fasync(int fd, struct file *filp, int on) | |
739 | { | |
0f7fc9e4 | 740 | struct inode *inode = filp->f_path.dentry->d_inode; |
341b446b | 741 | struct pipe_inode_info *pipe = inode->i_pipe; |
1da177e4 LT |
742 | int retval; |
743 | ||
9aeedfc4 | 744 | mutex_lock(&inode->i_mutex); |
341b446b | 745 | retval = fasync_helper(fd, filp, on, &pipe->fasync_readers); |
e5bc49ba | 746 | if (retval >= 0) { |
341b446b | 747 | retval = fasync_helper(fd, filp, on, &pipe->fasync_writers); |
e5bc49ba ON |
748 | if (retval < 0) /* this can happen only if on == T */ |
749 | fasync_helper(-1, filp, 0, &pipe->fasync_readers); | |
750 | } | |
9aeedfc4 | 751 | mutex_unlock(&inode->i_mutex); |
60aa4924 | 752 | return retval; |
1da177e4 LT |
753 | } |
754 | ||
755 | ||
756 | static int | |
757 | pipe_read_release(struct inode *inode, struct file *filp) | |
758 | { | |
1da177e4 LT |
759 | return pipe_release(inode, 1, 0); |
760 | } | |
761 | ||
762 | static int | |
763 | pipe_write_release(struct inode *inode, struct file *filp) | |
764 | { | |
1da177e4 LT |
765 | return pipe_release(inode, 0, 1); |
766 | } | |
767 | ||
768 | static int | |
769 | pipe_rdwr_release(struct inode *inode, struct file *filp) | |
770 | { | |
771 | int decr, decw; | |
772 | ||
1da177e4 LT |
773 | decr = (filp->f_mode & FMODE_READ) != 0; |
774 | decw = (filp->f_mode & FMODE_WRITE) != 0; | |
775 | return pipe_release(inode, decr, decw); | |
776 | } | |
777 | ||
778 | static int | |
779 | pipe_read_open(struct inode *inode, struct file *filp) | |
780 | { | |
ad396024 EC |
781 | int ret = -ENOENT; |
782 | ||
9aeedfc4 | 783 | mutex_lock(&inode->i_mutex); |
ad396024 EC |
784 | |
785 | if (inode->i_pipe) { | |
786 | ret = 0; | |
787 | inode->i_pipe->readers++; | |
788 | } | |
789 | ||
9aeedfc4 | 790 | mutex_unlock(&inode->i_mutex); |
1da177e4 | 791 | |
ad396024 | 792 | return ret; |
1da177e4 LT |
793 | } |
794 | ||
795 | static int | |
796 | pipe_write_open(struct inode *inode, struct file *filp) | |
797 | { | |
ad396024 EC |
798 | int ret = -ENOENT; |
799 | ||
9aeedfc4 | 800 | mutex_lock(&inode->i_mutex); |
ad396024 EC |
801 | |
802 | if (inode->i_pipe) { | |
803 | ret = 0; | |
804 | inode->i_pipe->writers++; | |
805 | } | |
806 | ||
9aeedfc4 | 807 | mutex_unlock(&inode->i_mutex); |
1da177e4 | 808 | |
ad396024 | 809 | return ret; |
1da177e4 LT |
810 | } |
811 | ||
812 | static int | |
813 | pipe_rdwr_open(struct inode *inode, struct file *filp) | |
814 | { | |
ad396024 EC |
815 | int ret = -ENOENT; |
816 | ||
9aeedfc4 | 817 | mutex_lock(&inode->i_mutex); |
ad396024 EC |
818 | |
819 | if (inode->i_pipe) { | |
820 | ret = 0; | |
821 | if (filp->f_mode & FMODE_READ) | |
822 | inode->i_pipe->readers++; | |
823 | if (filp->f_mode & FMODE_WRITE) | |
824 | inode->i_pipe->writers++; | |
825 | } | |
826 | ||
9aeedfc4 | 827 | mutex_unlock(&inode->i_mutex); |
1da177e4 | 828 | |
ad396024 | 829 | return ret; |
1da177e4 LT |
830 | } |
831 | ||
832 | /* | |
833 | * The file_operations structs are not static because they | |
834 | * are also used in linux/fs/fifo.c to do operations on FIFOs. | |
d2d9648e DV |
835 | * |
836 | * Pipes reuse fifos' file_operations structs. | |
1da177e4 | 837 | */ |
d2d9648e | 838 | const struct file_operations read_pipefifo_fops = { |
1da177e4 | 839 | .llseek = no_llseek, |
ee0b3e67 BP |
840 | .read = do_sync_read, |
841 | .aio_read = pipe_read, | |
1da177e4 LT |
842 | .write = bad_pipe_w, |
843 | .poll = pipe_poll, | |
d59d0b1b | 844 | .unlocked_ioctl = pipe_ioctl, |
1da177e4 LT |
845 | .open = pipe_read_open, |
846 | .release = pipe_read_release, | |
847 | .fasync = pipe_read_fasync, | |
848 | }; | |
849 | ||
d2d9648e | 850 | const struct file_operations write_pipefifo_fops = { |
1da177e4 LT |
851 | .llseek = no_llseek, |
852 | .read = bad_pipe_r, | |
ee0b3e67 BP |
853 | .write = do_sync_write, |
854 | .aio_write = pipe_write, | |
1da177e4 | 855 | .poll = pipe_poll, |
d59d0b1b | 856 | .unlocked_ioctl = pipe_ioctl, |
1da177e4 LT |
857 | .open = pipe_write_open, |
858 | .release = pipe_write_release, | |
859 | .fasync = pipe_write_fasync, | |
860 | }; | |
861 | ||
d2d9648e | 862 | const struct file_operations rdwr_pipefifo_fops = { |
1da177e4 | 863 | .llseek = no_llseek, |
ee0b3e67 BP |
864 | .read = do_sync_read, |
865 | .aio_read = pipe_read, | |
866 | .write = do_sync_write, | |
867 | .aio_write = pipe_write, | |
1da177e4 | 868 | .poll = pipe_poll, |
d59d0b1b | 869 | .unlocked_ioctl = pipe_ioctl, |
1da177e4 LT |
870 | .open = pipe_rdwr_open, |
871 | .release = pipe_rdwr_release, | |
872 | .fasync = pipe_rdwr_fasync, | |
873 | }; | |
874 | ||
3a326a2c IM |
875 | struct pipe_inode_info * alloc_pipe_info(struct inode *inode) |
876 | { | |
923f4f23 | 877 | struct pipe_inode_info *pipe; |
3a326a2c | 878 | |
923f4f23 IM |
879 | pipe = kzalloc(sizeof(struct pipe_inode_info), GFP_KERNEL); |
880 | if (pipe) { | |
35f3d14d JA |
881 | pipe->bufs = kzalloc(sizeof(struct pipe_buffer) * PIPE_DEF_BUFFERS, GFP_KERNEL); |
882 | if (pipe->bufs) { | |
883 | init_waitqueue_head(&pipe->wait); | |
884 | pipe->r_counter = pipe->w_counter = 1; | |
885 | pipe->inode = inode; | |
886 | pipe->buffers = PIPE_DEF_BUFFERS; | |
887 | return pipe; | |
888 | } | |
889 | kfree(pipe); | |
3a326a2c IM |
890 | } |
891 | ||
35f3d14d | 892 | return NULL; |
3a326a2c IM |
893 | } |
894 | ||
923f4f23 | 895 | void __free_pipe_info(struct pipe_inode_info *pipe) |
1da177e4 LT |
896 | { |
897 | int i; | |
1da177e4 | 898 | |
35f3d14d | 899 | for (i = 0; i < pipe->buffers; i++) { |
923f4f23 | 900 | struct pipe_buffer *buf = pipe->bufs + i; |
1da177e4 | 901 | if (buf->ops) |
923f4f23 | 902 | buf->ops->release(pipe, buf); |
1da177e4 | 903 | } |
923f4f23 IM |
904 | if (pipe->tmp_page) |
905 | __free_page(pipe->tmp_page); | |
35f3d14d | 906 | kfree(pipe->bufs); |
923f4f23 | 907 | kfree(pipe); |
1da177e4 LT |
908 | } |
909 | ||
b92ce558 JA |
910 | void free_pipe_info(struct inode *inode) |
911 | { | |
912 | __free_pipe_info(inode->i_pipe); | |
913 | inode->i_pipe = NULL; | |
914 | } | |
915 | ||
fa3536cc | 916 | static struct vfsmount *pipe_mnt __read_mostly; |
341b446b | 917 | |
c23fbb6b ED |
918 | /* |
919 | * pipefs_dname() is called from d_path(). | |
920 | */ | |
921 | static char *pipefs_dname(struct dentry *dentry, char *buffer, int buflen) | |
922 | { | |
923 | return dynamic_dname(dentry, buffer, buflen, "pipe:[%lu]", | |
924 | dentry->d_inode->i_ino); | |
925 | } | |
926 | ||
3ba13d17 | 927 | static const struct dentry_operations pipefs_dentry_operations = { |
c23fbb6b | 928 | .d_dname = pipefs_dname, |
1da177e4 LT |
929 | }; |
930 | ||
931 | static struct inode * get_pipe_inode(void) | |
932 | { | |
933 | struct inode *inode = new_inode(pipe_mnt->mnt_sb); | |
923f4f23 | 934 | struct pipe_inode_info *pipe; |
1da177e4 LT |
935 | |
936 | if (!inode) | |
937 | goto fail_inode; | |
938 | ||
923f4f23 IM |
939 | pipe = alloc_pipe_info(inode); |
940 | if (!pipe) | |
1da177e4 | 941 | goto fail_iput; |
923f4f23 | 942 | inode->i_pipe = pipe; |
3a326a2c | 943 | |
923f4f23 | 944 | pipe->readers = pipe->writers = 1; |
d2d9648e | 945 | inode->i_fop = &rdwr_pipefifo_fops; |
1da177e4 LT |
946 | |
947 | /* | |
948 | * Mark the inode dirty from the very beginning, | |
949 | * that way it will never be moved to the dirty | |
950 | * list because "mark_inode_dirty()" will think | |
951 | * that it already _is_ on the dirty list. | |
952 | */ | |
953 | inode->i_state = I_DIRTY; | |
954 | inode->i_mode = S_IFIFO | S_IRUSR | S_IWUSR; | |
da9592ed DH |
955 | inode->i_uid = current_fsuid(); |
956 | inode->i_gid = current_fsgid(); | |
1da177e4 | 957 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; |
923f4f23 | 958 | |
1da177e4 LT |
959 | return inode; |
960 | ||
961 | fail_iput: | |
962 | iput(inode); | |
341b446b | 963 | |
1da177e4 LT |
964 | fail_inode: |
965 | return NULL; | |
966 | } | |
967 | ||
be61a86d | 968 | struct file *create_write_pipe(int flags) |
1da177e4 | 969 | { |
d6cbd281 AK |
970 | int err; |
971 | struct inode *inode; | |
972 | struct file *f; | |
2c48b9c4 | 973 | struct path path; |
c23fbb6b | 974 | struct qstr name = { .name = "" }; |
1da177e4 | 975 | |
d6cbd281 | 976 | err = -ENFILE; |
1da177e4 LT |
977 | inode = get_pipe_inode(); |
978 | if (!inode) | |
430e285e | 979 | goto err; |
1da177e4 | 980 | |
d6cbd281 | 981 | err = -ENOMEM; |
2c48b9c4 AV |
982 | path.dentry = d_alloc(pipe_mnt->mnt_sb->s_root, &name); |
983 | if (!path.dentry) | |
d6cbd281 | 984 | goto err_inode; |
2c48b9c4 | 985 | path.mnt = mntget(pipe_mnt); |
341b446b | 986 | |
2c48b9c4 | 987 | path.dentry->d_op = &pipefs_dentry_operations; |
2c48b9c4 | 988 | d_instantiate(path.dentry, inode); |
430e285e DH |
989 | |
990 | err = -ENFILE; | |
2c48b9c4 | 991 | f = alloc_file(&path, FMODE_WRITE, &write_pipefifo_fops); |
430e285e DH |
992 | if (!f) |
993 | goto err_dentry; | |
d6cbd281 | 994 | f->f_mapping = inode->i_mapping; |
341b446b | 995 | |
be61a86d | 996 | f->f_flags = O_WRONLY | (flags & O_NONBLOCK); |
d6cbd281 AK |
997 | f->f_version = 0; |
998 | ||
999 | return f; | |
1da177e4 | 1000 | |
430e285e | 1001 | err_dentry: |
ed152437 | 1002 | free_pipe_info(inode); |
2c48b9c4 | 1003 | path_put(&path); |
ed152437 AV |
1004 | return ERR_PTR(err); |
1005 | ||
d6cbd281 | 1006 | err_inode: |
1da177e4 LT |
1007 | free_pipe_info(inode); |
1008 | iput(inode); | |
430e285e | 1009 | err: |
d6cbd281 AK |
1010 | return ERR_PTR(err); |
1011 | } | |
1012 | ||
1013 | void free_write_pipe(struct file *f) | |
1014 | { | |
5ccac88e | 1015 | free_pipe_info(f->f_dentry->d_inode); |
c8e7f449 | 1016 | path_put(&f->f_path); |
d6cbd281 AK |
1017 | put_filp(f); |
1018 | } | |
1019 | ||
be61a86d | 1020 | struct file *create_read_pipe(struct file *wrf, int flags) |
d6cbd281 | 1021 | { |
d231412d AV |
1022 | /* Grab pipe from the writer */ |
1023 | struct file *f = alloc_file(&wrf->f_path, FMODE_READ, | |
1024 | &read_pipefifo_fops); | |
d6cbd281 AK |
1025 | if (!f) |
1026 | return ERR_PTR(-ENFILE); | |
1027 | ||
c8e7f449 | 1028 | path_get(&wrf->f_path); |
be61a86d | 1029 | f->f_flags = O_RDONLY | (flags & O_NONBLOCK); |
d6cbd281 AK |
1030 | |
1031 | return f; | |
1032 | } | |
1033 | ||
ed8cae8b | 1034 | int do_pipe_flags(int *fd, int flags) |
d6cbd281 AK |
1035 | { |
1036 | struct file *fw, *fr; | |
1037 | int error; | |
1038 | int fdw, fdr; | |
1039 | ||
be61a86d | 1040 | if (flags & ~(O_CLOEXEC | O_NONBLOCK)) |
ed8cae8b UD |
1041 | return -EINVAL; |
1042 | ||
be61a86d | 1043 | fw = create_write_pipe(flags); |
d6cbd281 AK |
1044 | if (IS_ERR(fw)) |
1045 | return PTR_ERR(fw); | |
be61a86d | 1046 | fr = create_read_pipe(fw, flags); |
d6cbd281 AK |
1047 | error = PTR_ERR(fr); |
1048 | if (IS_ERR(fr)) | |
1049 | goto err_write_pipe; | |
1050 | ||
ed8cae8b | 1051 | error = get_unused_fd_flags(flags); |
d6cbd281 AK |
1052 | if (error < 0) |
1053 | goto err_read_pipe; | |
1054 | fdr = error; | |
1055 | ||
ed8cae8b | 1056 | error = get_unused_fd_flags(flags); |
d6cbd281 AK |
1057 | if (error < 0) |
1058 | goto err_fdr; | |
1059 | fdw = error; | |
1060 | ||
157cf649 | 1061 | audit_fd_pair(fdr, fdw); |
d6cbd281 AK |
1062 | fd_install(fdr, fr); |
1063 | fd_install(fdw, fw); | |
1064 | fd[0] = fdr; | |
1065 | fd[1] = fdw; | |
1066 | ||
1067 | return 0; | |
1068 | ||
1069 | err_fdr: | |
1070 | put_unused_fd(fdr); | |
1071 | err_read_pipe: | |
c8e7f449 | 1072 | path_put(&fr->f_path); |
d6cbd281 AK |
1073 | put_filp(fr); |
1074 | err_write_pipe: | |
1075 | free_write_pipe(fw); | |
1076 | return error; | |
1da177e4 LT |
1077 | } |
1078 | ||
d35c7b0e UD |
1079 | /* |
1080 | * sys_pipe() is the normal C calling standard for creating | |
1081 | * a pipe. It's not the way Unix traditionally does this, though. | |
1082 | */ | |
d4e82042 | 1083 | SYSCALL_DEFINE2(pipe2, int __user *, fildes, int, flags) |
d35c7b0e UD |
1084 | { |
1085 | int fd[2]; | |
1086 | int error; | |
1087 | ||
ed8cae8b | 1088 | error = do_pipe_flags(fd, flags); |
d35c7b0e | 1089 | if (!error) { |
ba719bae UD |
1090 | if (copy_to_user(fildes, fd, sizeof(fd))) { |
1091 | sys_close(fd[0]); | |
1092 | sys_close(fd[1]); | |
d35c7b0e | 1093 | error = -EFAULT; |
ba719bae | 1094 | } |
d35c7b0e UD |
1095 | } |
1096 | return error; | |
1097 | } | |
1098 | ||
2b664219 | 1099 | SYSCALL_DEFINE1(pipe, int __user *, fildes) |
ed8cae8b UD |
1100 | { |
1101 | return sys_pipe2(fildes, 0); | |
1102 | } | |
1103 | ||
35f3d14d JA |
1104 | /* |
1105 | * Allocate a new array of pipe buffers and copy the info over. Returns the | |
1106 | * pipe size if successful, or return -ERROR on error. | |
1107 | */ | |
1108 | static long pipe_set_size(struct pipe_inode_info *pipe, unsigned long arg) | |
1109 | { | |
1110 | struct pipe_buffer *bufs; | |
1111 | ||
1112 | /* | |
1113 | * Must be a power-of-2 currently | |
1114 | */ | |
1115 | if (!is_power_of_2(arg)) | |
1116 | return -EINVAL; | |
1117 | ||
1118 | /* | |
1119 | * We can shrink the pipe, if arg >= pipe->nrbufs. Since we don't | |
1120 | * expect a lot of shrink+grow operations, just free and allocate | |
1121 | * again like we would do for growing. If the pipe currently | |
1122 | * contains more buffers than arg, then return busy. | |
1123 | */ | |
1124 | if (arg < pipe->nrbufs) | |
1125 | return -EBUSY; | |
1126 | ||
1127 | bufs = kcalloc(arg, sizeof(struct pipe_buffer), GFP_KERNEL); | |
1128 | if (unlikely(!bufs)) | |
1129 | return -ENOMEM; | |
1130 | ||
1131 | /* | |
1132 | * The pipe array wraps around, so just start the new one at zero | |
1133 | * and adjust the indexes. | |
1134 | */ | |
1135 | if (pipe->nrbufs) { | |
1136 | const unsigned int tail = pipe->nrbufs & (pipe->buffers - 1); | |
1137 | const unsigned int head = pipe->nrbufs - tail; | |
1138 | ||
1139 | if (head) | |
1140 | memcpy(bufs, pipe->bufs + pipe->curbuf, head * sizeof(struct pipe_buffer)); | |
1141 | if (tail) | |
1142 | memcpy(bufs + head, pipe->bufs + pipe->curbuf, tail * sizeof(struct pipe_buffer)); | |
1143 | } | |
1144 | ||
1145 | pipe->curbuf = 0; | |
1146 | kfree(pipe->bufs); | |
1147 | pipe->bufs = bufs; | |
1148 | pipe->buffers = arg; | |
1149 | return arg; | |
1150 | } | |
1151 | ||
1152 | long pipe_fcntl(struct file *file, unsigned int cmd, unsigned long arg) | |
1153 | { | |
1154 | struct pipe_inode_info *pipe; | |
1155 | long ret; | |
1156 | ||
1157 | pipe = file->f_path.dentry->d_inode->i_pipe; | |
1158 | if (!pipe) | |
1159 | return -EBADF; | |
1160 | ||
1161 | mutex_lock(&pipe->inode->i_mutex); | |
1162 | ||
1163 | switch (cmd) { | |
1164 | case F_SETPIPE_SZ: | |
1165 | ret = pipe_set_size(pipe, arg); | |
1166 | break; | |
1167 | case F_GETPIPE_SZ: | |
1168 | ret = pipe->buffers; | |
1169 | break; | |
1170 | default: | |
1171 | ret = -EINVAL; | |
1172 | break; | |
1173 | } | |
1174 | ||
1175 | mutex_unlock(&pipe->inode->i_mutex); | |
1176 | return ret; | |
1177 | } | |
1178 | ||
1da177e4 LT |
1179 | /* |
1180 | * pipefs should _never_ be mounted by userland - too much of security hassle, | |
1181 | * no real gain from having the whole whorehouse mounted. So we don't need | |
1182 | * any operations on the root directory. However, we need a non-trivial | |
1183 | * d_name - pipe: will go nicely and kill the special-casing in procfs. | |
1184 | */ | |
454e2398 DH |
1185 | static int pipefs_get_sb(struct file_system_type *fs_type, |
1186 | int flags, const char *dev_name, void *data, | |
1187 | struct vfsmount *mnt) | |
1da177e4 | 1188 | { |
454e2398 | 1189 | return get_sb_pseudo(fs_type, "pipe:", NULL, PIPEFS_MAGIC, mnt); |
1da177e4 LT |
1190 | } |
1191 | ||
1192 | static struct file_system_type pipe_fs_type = { | |
1193 | .name = "pipefs", | |
1194 | .get_sb = pipefs_get_sb, | |
1195 | .kill_sb = kill_anon_super, | |
1196 | }; | |
1197 | ||
1198 | static int __init init_pipe_fs(void) | |
1199 | { | |
1200 | int err = register_filesystem(&pipe_fs_type); | |
341b446b | 1201 | |
1da177e4 LT |
1202 | if (!err) { |
1203 | pipe_mnt = kern_mount(&pipe_fs_type); | |
1204 | if (IS_ERR(pipe_mnt)) { | |
1205 | err = PTR_ERR(pipe_mnt); | |
1206 | unregister_filesystem(&pipe_fs_type); | |
1207 | } | |
1208 | } | |
1209 | return err; | |
1210 | } | |
1211 | ||
1212 | static void __exit exit_pipe_fs(void) | |
1213 | { | |
1214 | unregister_filesystem(&pipe_fs_type); | |
1215 | mntput(pipe_mnt); | |
1216 | } | |
1217 | ||
1218 | fs_initcall(init_pipe_fs); | |
1219 | module_exit(exit_pipe_fs); |