]>
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 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> |
b492e95b | 22 | #include <linux/fcntl.h> |
1da177e4 LT |
23 | |
24 | #include <asm/uaccess.h> | |
25 | #include <asm/ioctls.h> | |
26 | ||
b492e95b JA |
27 | /* |
28 | * The max size that a non-root user is allowed to grow the pipe. Can | |
29 | * be set by root in /proc/sys/fs/pipe-max-pages | |
30 | */ | |
31 | unsigned int pipe_max_pages = PIPE_DEF_BUFFERS * 16; | |
32 | ||
1da177e4 LT |
33 | /* |
34 | * We use a start+len construction, which provides full use of the | |
35 | * allocated memory. | |
36 | * -- Florian Coosmann (FGC) | |
37 | * | |
38 | * Reads with count = 0 should always return 0. | |
39 | * -- Julian Bradfield 1999-06-07. | |
40 | * | |
41 | * FIFOs and Pipes now generate SIGIO for both readers and writers. | |
42 | * -- Jeremy Elson <jelson@circlemud.org> 2001-08-16 | |
43 | * | |
44 | * pipe_read & write cleanup | |
45 | * -- Manfred Spraul <manfred@colorfullife.com> 2002-05-09 | |
46 | */ | |
47 | ||
61e0d47c MS |
48 | static void pipe_lock_nested(struct pipe_inode_info *pipe, int subclass) |
49 | { | |
50 | if (pipe->inode) | |
51 | mutex_lock_nested(&pipe->inode->i_mutex, subclass); | |
52 | } | |
53 | ||
54 | void pipe_lock(struct pipe_inode_info *pipe) | |
55 | { | |
56 | /* | |
57 | * pipe_lock() nests non-pipe inode locks (for writing to a file) | |
58 | */ | |
59 | pipe_lock_nested(pipe, I_MUTEX_PARENT); | |
60 | } | |
61 | EXPORT_SYMBOL(pipe_lock); | |
62 | ||
63 | void pipe_unlock(struct pipe_inode_info *pipe) | |
64 | { | |
65 | if (pipe->inode) | |
66 | mutex_unlock(&pipe->inode->i_mutex); | |
67 | } | |
68 | EXPORT_SYMBOL(pipe_unlock); | |
69 | ||
70 | void pipe_double_lock(struct pipe_inode_info *pipe1, | |
71 | struct pipe_inode_info *pipe2) | |
72 | { | |
73 | BUG_ON(pipe1 == pipe2); | |
74 | ||
75 | if (pipe1 < pipe2) { | |
76 | pipe_lock_nested(pipe1, I_MUTEX_PARENT); | |
77 | pipe_lock_nested(pipe2, I_MUTEX_CHILD); | |
78 | } else { | |
023d43c7 PZ |
79 | pipe_lock_nested(pipe2, I_MUTEX_PARENT); |
80 | pipe_lock_nested(pipe1, I_MUTEX_CHILD); | |
61e0d47c MS |
81 | } |
82 | } | |
83 | ||
1da177e4 | 84 | /* Drop the inode semaphore and wait for a pipe event, atomically */ |
3a326a2c | 85 | void pipe_wait(struct pipe_inode_info *pipe) |
1da177e4 LT |
86 | { |
87 | DEFINE_WAIT(wait); | |
88 | ||
d79fc0fc IM |
89 | /* |
90 | * Pipes are system-local resources, so sleeping on them | |
91 | * is considered a noninteractive wait: | |
92 | */ | |
af927232 | 93 | prepare_to_wait(&pipe->wait, &wait, TASK_INTERRUPTIBLE); |
61e0d47c | 94 | pipe_unlock(pipe); |
1da177e4 | 95 | schedule(); |
3a326a2c | 96 | finish_wait(&pipe->wait, &wait); |
61e0d47c | 97 | pipe_lock(pipe); |
1da177e4 LT |
98 | } |
99 | ||
858119e1 | 100 | static int |
f6762b7a JA |
101 | pipe_iov_copy_from_user(void *to, struct iovec *iov, unsigned long len, |
102 | int atomic) | |
1da177e4 LT |
103 | { |
104 | unsigned long copy; | |
105 | ||
106 | while (len > 0) { | |
107 | while (!iov->iov_len) | |
108 | iov++; | |
109 | copy = min_t(unsigned long, len, iov->iov_len); | |
110 | ||
f6762b7a JA |
111 | if (atomic) { |
112 | if (__copy_from_user_inatomic(to, iov->iov_base, copy)) | |
113 | return -EFAULT; | |
114 | } else { | |
115 | if (copy_from_user(to, iov->iov_base, copy)) | |
116 | return -EFAULT; | |
117 | } | |
1da177e4 LT |
118 | to += copy; |
119 | len -= copy; | |
120 | iov->iov_base += copy; | |
121 | iov->iov_len -= copy; | |
122 | } | |
123 | return 0; | |
124 | } | |
125 | ||
858119e1 | 126 | static int |
f6762b7a JA |
127 | pipe_iov_copy_to_user(struct iovec *iov, const void *from, unsigned long len, |
128 | int atomic) | |
1da177e4 LT |
129 | { |
130 | unsigned long copy; | |
131 | ||
132 | while (len > 0) { | |
133 | while (!iov->iov_len) | |
134 | iov++; | |
135 | copy = min_t(unsigned long, len, iov->iov_len); | |
136 | ||
f6762b7a JA |
137 | if (atomic) { |
138 | if (__copy_to_user_inatomic(iov->iov_base, from, copy)) | |
139 | return -EFAULT; | |
140 | } else { | |
141 | if (copy_to_user(iov->iov_base, from, copy)) | |
142 | return -EFAULT; | |
143 | } | |
1da177e4 LT |
144 | from += copy; |
145 | len -= copy; | |
146 | iov->iov_base += copy; | |
147 | iov->iov_len -= copy; | |
148 | } | |
149 | return 0; | |
150 | } | |
151 | ||
f6762b7a JA |
152 | /* |
153 | * Attempt to pre-fault in the user memory, so we can use atomic copies. | |
154 | * Returns the number of bytes not faulted in. | |
155 | */ | |
156 | static int iov_fault_in_pages_write(struct iovec *iov, unsigned long len) | |
157 | { | |
158 | while (!iov->iov_len) | |
159 | iov++; | |
160 | ||
161 | while (len > 0) { | |
162 | unsigned long this_len; | |
163 | ||
164 | this_len = min_t(unsigned long, len, iov->iov_len); | |
165 | if (fault_in_pages_writeable(iov->iov_base, this_len)) | |
166 | break; | |
167 | ||
168 | len -= this_len; | |
169 | iov++; | |
170 | } | |
171 | ||
172 | return len; | |
173 | } | |
174 | ||
175 | /* | |
176 | * Pre-fault in the user memory, so we can use atomic copies. | |
177 | */ | |
178 | static void iov_fault_in_pages_read(struct iovec *iov, unsigned long len) | |
179 | { | |
180 | while (!iov->iov_len) | |
181 | iov++; | |
182 | ||
183 | while (len > 0) { | |
184 | unsigned long this_len; | |
185 | ||
186 | this_len = min_t(unsigned long, len, iov->iov_len); | |
187 | fault_in_pages_readable(iov->iov_base, this_len); | |
188 | len -= this_len; | |
189 | iov++; | |
190 | } | |
191 | } | |
192 | ||
341b446b IM |
193 | static void anon_pipe_buf_release(struct pipe_inode_info *pipe, |
194 | struct pipe_buffer *buf) | |
1da177e4 LT |
195 | { |
196 | struct page *page = buf->page; | |
197 | ||
5274f052 JA |
198 | /* |
199 | * If nobody else uses this page, and we don't already have a | |
200 | * temporary page, let's keep track of it as a one-deep | |
341b446b | 201 | * allocation cache. (Otherwise just release our reference to it) |
5274f052 | 202 | */ |
341b446b | 203 | if (page_count(page) == 1 && !pipe->tmp_page) |
923f4f23 | 204 | pipe->tmp_page = page; |
341b446b IM |
205 | else |
206 | page_cache_release(page); | |
1da177e4 LT |
207 | } |
208 | ||
0845718d JA |
209 | /** |
210 | * generic_pipe_buf_map - virtually map a pipe buffer | |
211 | * @pipe: the pipe that the buffer belongs to | |
212 | * @buf: the buffer that should be mapped | |
213 | * @atomic: whether to use an atomic map | |
214 | * | |
215 | * Description: | |
216 | * This function returns a kernel virtual address mapping for the | |
b51d63c6 | 217 | * pipe_buffer passed in @buf. If @atomic is set, an atomic map is provided |
0845718d JA |
218 | * and the caller has to be careful not to fault before calling |
219 | * the unmap function. | |
220 | * | |
221 | * Note that this function occupies KM_USER0 if @atomic != 0. | |
222 | */ | |
f84d7519 | 223 | void *generic_pipe_buf_map(struct pipe_inode_info *pipe, |
f6762b7a | 224 | struct pipe_buffer *buf, int atomic) |
1da177e4 | 225 | { |
f6762b7a JA |
226 | if (atomic) { |
227 | buf->flags |= PIPE_BUF_FLAG_ATOMIC; | |
228 | return kmap_atomic(buf->page, KM_USER0); | |
229 | } | |
230 | ||
1da177e4 LT |
231 | return kmap(buf->page); |
232 | } | |
233 | ||
0845718d JA |
234 | /** |
235 | * generic_pipe_buf_unmap - unmap a previously mapped pipe buffer | |
236 | * @pipe: the pipe that the buffer belongs to | |
237 | * @buf: the buffer that should be unmapped | |
238 | * @map_data: the data that the mapping function returned | |
239 | * | |
240 | * Description: | |
241 | * This function undoes the mapping that ->map() provided. | |
242 | */ | |
f84d7519 | 243 | void generic_pipe_buf_unmap(struct pipe_inode_info *pipe, |
f6762b7a | 244 | struct pipe_buffer *buf, void *map_data) |
1da177e4 | 245 | { |
f6762b7a JA |
246 | if (buf->flags & PIPE_BUF_FLAG_ATOMIC) { |
247 | buf->flags &= ~PIPE_BUF_FLAG_ATOMIC; | |
248 | kunmap_atomic(map_data, KM_USER0); | |
249 | } else | |
250 | kunmap(buf->page); | |
1da177e4 LT |
251 | } |
252 | ||
0845718d | 253 | /** |
b51d63c6 | 254 | * generic_pipe_buf_steal - attempt to take ownership of a &pipe_buffer |
0845718d JA |
255 | * @pipe: the pipe that the buffer belongs to |
256 | * @buf: the buffer to attempt to steal | |
257 | * | |
258 | * Description: | |
b51d63c6 | 259 | * This function attempts to steal the &struct page attached to |
0845718d JA |
260 | * @buf. If successful, this function returns 0 and returns with |
261 | * the page locked. The caller may then reuse the page for whatever | |
b51d63c6 | 262 | * he wishes; the typical use is insertion into a different file |
0845718d JA |
263 | * page cache. |
264 | */ | |
330ab716 JA |
265 | int generic_pipe_buf_steal(struct pipe_inode_info *pipe, |
266 | struct pipe_buffer *buf) | |
5abc97aa | 267 | { |
46e678c9 JA |
268 | struct page *page = buf->page; |
269 | ||
0845718d JA |
270 | /* |
271 | * A reference of one is golden, that means that the owner of this | |
272 | * page is the only one holding a reference to it. lock the page | |
273 | * and return OK. | |
274 | */ | |
46e678c9 | 275 | if (page_count(page) == 1) { |
46e678c9 JA |
276 | lock_page(page); |
277 | return 0; | |
278 | } | |
279 | ||
280 | return 1; | |
5abc97aa JA |
281 | } |
282 | ||
0845718d | 283 | /** |
b51d63c6 | 284 | * generic_pipe_buf_get - get a reference to a &struct pipe_buffer |
0845718d JA |
285 | * @pipe: the pipe that the buffer belongs to |
286 | * @buf: the buffer to get a reference to | |
287 | * | |
288 | * Description: | |
289 | * This function grabs an extra reference to @buf. It's used in | |
290 | * in the tee() system call, when we duplicate the buffers in one | |
291 | * pipe into another. | |
292 | */ | |
293 | void generic_pipe_buf_get(struct pipe_inode_info *pipe, struct pipe_buffer *buf) | |
70524490 JA |
294 | { |
295 | page_cache_get(buf->page); | |
296 | } | |
297 | ||
0845718d JA |
298 | /** |
299 | * generic_pipe_buf_confirm - verify contents of the pipe buffer | |
79685b8d | 300 | * @info: the pipe that the buffer belongs to |
0845718d JA |
301 | * @buf: the buffer to confirm |
302 | * | |
303 | * Description: | |
304 | * This function does nothing, because the generic pipe code uses | |
305 | * pages that are always good when inserted into the pipe. | |
306 | */ | |
cac36bb0 JA |
307 | int generic_pipe_buf_confirm(struct pipe_inode_info *info, |
308 | struct pipe_buffer *buf) | |
f84d7519 JA |
309 | { |
310 | return 0; | |
311 | } | |
312 | ||
6818173b MS |
313 | /** |
314 | * generic_pipe_buf_release - put a reference to a &struct pipe_buffer | |
315 | * @pipe: the pipe that the buffer belongs to | |
316 | * @buf: the buffer to put a reference to | |
317 | * | |
318 | * Description: | |
319 | * This function releases a reference to @buf. | |
320 | */ | |
321 | void generic_pipe_buf_release(struct pipe_inode_info *pipe, | |
322 | struct pipe_buffer *buf) | |
323 | { | |
324 | page_cache_release(buf->page); | |
325 | } | |
326 | ||
d4c3cca9 | 327 | static const struct pipe_buf_operations anon_pipe_buf_ops = { |
1da177e4 | 328 | .can_merge = 1, |
f84d7519 JA |
329 | .map = generic_pipe_buf_map, |
330 | .unmap = generic_pipe_buf_unmap, | |
cac36bb0 | 331 | .confirm = generic_pipe_buf_confirm, |
1da177e4 | 332 | .release = anon_pipe_buf_release, |
330ab716 | 333 | .steal = generic_pipe_buf_steal, |
f84d7519 | 334 | .get = generic_pipe_buf_get, |
1da177e4 LT |
335 | }; |
336 | ||
337 | static ssize_t | |
ee0b3e67 BP |
338 | pipe_read(struct kiocb *iocb, const struct iovec *_iov, |
339 | unsigned long nr_segs, loff_t pos) | |
1da177e4 | 340 | { |
ee0b3e67 | 341 | struct file *filp = iocb->ki_filp; |
0f7fc9e4 | 342 | struct inode *inode = filp->f_path.dentry->d_inode; |
923f4f23 | 343 | struct pipe_inode_info *pipe; |
1da177e4 LT |
344 | int do_wakeup; |
345 | ssize_t ret; | |
346 | struct iovec *iov = (struct iovec *)_iov; | |
347 | size_t total_len; | |
348 | ||
349 | total_len = iov_length(iov, nr_segs); | |
350 | /* Null read succeeds. */ | |
351 | if (unlikely(total_len == 0)) | |
352 | return 0; | |
353 | ||
354 | do_wakeup = 0; | |
355 | ret = 0; | |
9aeedfc4 | 356 | mutex_lock(&inode->i_mutex); |
923f4f23 | 357 | pipe = inode->i_pipe; |
1da177e4 | 358 | for (;;) { |
923f4f23 | 359 | int bufs = pipe->nrbufs; |
1da177e4 | 360 | if (bufs) { |
923f4f23 IM |
361 | int curbuf = pipe->curbuf; |
362 | struct pipe_buffer *buf = pipe->bufs + curbuf; | |
d4c3cca9 | 363 | const struct pipe_buf_operations *ops = buf->ops; |
1da177e4 LT |
364 | void *addr; |
365 | size_t chars = buf->len; | |
f6762b7a | 366 | int error, atomic; |
1da177e4 LT |
367 | |
368 | if (chars > total_len) | |
369 | chars = total_len; | |
370 | ||
cac36bb0 | 371 | error = ops->confirm(pipe, buf); |
f84d7519 | 372 | if (error) { |
5274f052 | 373 | if (!ret) |
f84d7519 | 374 | error = ret; |
5274f052 JA |
375 | break; |
376 | } | |
f84d7519 | 377 | |
f6762b7a JA |
378 | atomic = !iov_fault_in_pages_write(iov, chars); |
379 | redo: | |
380 | addr = ops->map(pipe, buf, atomic); | |
381 | error = pipe_iov_copy_to_user(iov, addr + buf->offset, chars, atomic); | |
382 | ops->unmap(pipe, buf, addr); | |
1da177e4 | 383 | if (unlikely(error)) { |
f6762b7a JA |
384 | /* |
385 | * Just retry with the slow path if we failed. | |
386 | */ | |
387 | if (atomic) { | |
388 | atomic = 0; | |
389 | goto redo; | |
390 | } | |
341b446b | 391 | if (!ret) |
f6762b7a | 392 | ret = error; |
1da177e4 LT |
393 | break; |
394 | } | |
395 | ret += chars; | |
396 | buf->offset += chars; | |
397 | buf->len -= chars; | |
398 | if (!buf->len) { | |
399 | buf->ops = NULL; | |
923f4f23 | 400 | ops->release(pipe, buf); |
35f3d14d | 401 | curbuf = (curbuf + 1) & (pipe->buffers - 1); |
923f4f23 IM |
402 | pipe->curbuf = curbuf; |
403 | pipe->nrbufs = --bufs; | |
1da177e4 LT |
404 | do_wakeup = 1; |
405 | } | |
406 | total_len -= chars; | |
407 | if (!total_len) | |
408 | break; /* common path: read succeeded */ | |
409 | } | |
410 | if (bufs) /* More to do? */ | |
411 | continue; | |
923f4f23 | 412 | if (!pipe->writers) |
1da177e4 | 413 | break; |
923f4f23 | 414 | if (!pipe->waiting_writers) { |
1da177e4 LT |
415 | /* syscall merging: Usually we must not sleep |
416 | * if O_NONBLOCK is set, or if we got some data. | |
417 | * But if a writer sleeps in kernel space, then | |
418 | * we can wait for that data without violating POSIX. | |
419 | */ | |
420 | if (ret) | |
421 | break; | |
422 | if (filp->f_flags & O_NONBLOCK) { | |
423 | ret = -EAGAIN; | |
424 | break; | |
425 | } | |
426 | } | |
427 | if (signal_pending(current)) { | |
341b446b IM |
428 | if (!ret) |
429 | ret = -ERESTARTSYS; | |
1da177e4 LT |
430 | break; |
431 | } | |
432 | if (do_wakeup) { | |
923f4f23 IM |
433 | wake_up_interruptible_sync(&pipe->wait); |
434 | kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); | |
1da177e4 | 435 | } |
923f4f23 | 436 | pipe_wait(pipe); |
1da177e4 | 437 | } |
9aeedfc4 | 438 | mutex_unlock(&inode->i_mutex); |
341b446b IM |
439 | |
440 | /* Signal writers asynchronously that there is more room. */ | |
1da177e4 | 441 | if (do_wakeup) { |
71e20f18 | 442 | wake_up_interruptible_sync(&pipe->wait); |
923f4f23 | 443 | kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); |
1da177e4 LT |
444 | } |
445 | if (ret > 0) | |
446 | file_accessed(filp); | |
447 | return ret; | |
448 | } | |
449 | ||
450 | static ssize_t | |
ee0b3e67 BP |
451 | pipe_write(struct kiocb *iocb, const struct iovec *_iov, |
452 | unsigned long nr_segs, loff_t ppos) | |
1da177e4 | 453 | { |
ee0b3e67 | 454 | struct file *filp = iocb->ki_filp; |
0f7fc9e4 | 455 | struct inode *inode = filp->f_path.dentry->d_inode; |
923f4f23 | 456 | struct pipe_inode_info *pipe; |
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; | |
9aeedfc4 | 470 | mutex_lock(&inode->i_mutex); |
923f4f23 | 471 | pipe = inode->i_pipe; |
1da177e4 | 472 | |
923f4f23 | 473 | if (!pipe->readers) { |
1da177e4 LT |
474 | send_sig(SIGPIPE, current, 0); |
475 | ret = -EPIPE; | |
476 | goto out; | |
477 | } | |
478 | ||
479 | /* We try to merge small writes */ | |
480 | chars = total_len & (PAGE_SIZE-1); /* size of the last buffer */ | |
923f4f23 | 481 | if (pipe->nrbufs && chars != 0) { |
341b446b | 482 | int lastbuf = (pipe->curbuf + pipe->nrbufs - 1) & |
35f3d14d | 483 | (pipe->buffers - 1); |
923f4f23 | 484 | struct pipe_buffer *buf = pipe->bufs + lastbuf; |
d4c3cca9 | 485 | const struct pipe_buf_operations *ops = buf->ops; |
1da177e4 | 486 | int offset = buf->offset + buf->len; |
341b446b | 487 | |
1da177e4 | 488 | if (ops->can_merge && offset + chars <= PAGE_SIZE) { |
f6762b7a | 489 | int error, atomic = 1; |
5274f052 | 490 | void *addr; |
5274f052 | 491 | |
cac36bb0 | 492 | error = ops->confirm(pipe, buf); |
f84d7519 | 493 | if (error) |
5274f052 | 494 | goto out; |
f84d7519 | 495 | |
f6762b7a JA |
496 | iov_fault_in_pages_read(iov, chars); |
497 | redo1: | |
498 | addr = ops->map(pipe, buf, atomic); | |
5274f052 | 499 | error = pipe_iov_copy_from_user(offset + addr, iov, |
f6762b7a JA |
500 | chars, atomic); |
501 | ops->unmap(pipe, buf, addr); | |
1da177e4 LT |
502 | ret = error; |
503 | do_wakeup = 1; | |
f6762b7a JA |
504 | if (error) { |
505 | if (atomic) { | |
506 | atomic = 0; | |
507 | goto redo1; | |
508 | } | |
1da177e4 | 509 | goto out; |
f6762b7a | 510 | } |
1da177e4 LT |
511 | buf->len += chars; |
512 | total_len -= chars; | |
513 | ret = chars; | |
514 | if (!total_len) | |
515 | goto out; | |
516 | } | |
517 | } | |
518 | ||
519 | for (;;) { | |
520 | int bufs; | |
341b446b | 521 | |
923f4f23 | 522 | if (!pipe->readers) { |
1da177e4 | 523 | send_sig(SIGPIPE, current, 0); |
341b446b IM |
524 | if (!ret) |
525 | ret = -EPIPE; | |
1da177e4 LT |
526 | break; |
527 | } | |
923f4f23 | 528 | bufs = pipe->nrbufs; |
35f3d14d JA |
529 | if (bufs < pipe->buffers) { |
530 | int newbuf = (pipe->curbuf + bufs) & (pipe->buffers-1); | |
923f4f23 IM |
531 | struct pipe_buffer *buf = pipe->bufs + newbuf; |
532 | struct page *page = pipe->tmp_page; | |
f6762b7a JA |
533 | char *src; |
534 | int error, atomic = 1; | |
1da177e4 LT |
535 | |
536 | if (!page) { | |
537 | page = alloc_page(GFP_HIGHUSER); | |
538 | if (unlikely(!page)) { | |
539 | ret = ret ? : -ENOMEM; | |
540 | break; | |
541 | } | |
923f4f23 | 542 | pipe->tmp_page = page; |
1da177e4 | 543 | } |
341b446b | 544 | /* Always wake up, even if the copy fails. Otherwise |
1da177e4 LT |
545 | * we lock up (O_NONBLOCK-)readers that sleep due to |
546 | * syscall merging. | |
547 | * FIXME! Is this really true? | |
548 | */ | |
549 | do_wakeup = 1; | |
550 | chars = PAGE_SIZE; | |
551 | if (chars > total_len) | |
552 | chars = total_len; | |
553 | ||
f6762b7a JA |
554 | iov_fault_in_pages_read(iov, chars); |
555 | redo2: | |
556 | if (atomic) | |
557 | src = kmap_atomic(page, KM_USER0); | |
558 | else | |
559 | src = kmap(page); | |
560 | ||
561 | error = pipe_iov_copy_from_user(src, iov, chars, | |
562 | atomic); | |
563 | if (atomic) | |
564 | kunmap_atomic(src, KM_USER0); | |
565 | else | |
566 | kunmap(page); | |
567 | ||
1da177e4 | 568 | if (unlikely(error)) { |
f6762b7a JA |
569 | if (atomic) { |
570 | atomic = 0; | |
571 | goto redo2; | |
572 | } | |
341b446b | 573 | if (!ret) |
f6762b7a | 574 | ret = error; |
1da177e4 LT |
575 | break; |
576 | } | |
577 | ret += chars; | |
578 | ||
579 | /* Insert it into the buffer array */ | |
580 | buf->page = page; | |
581 | buf->ops = &anon_pipe_buf_ops; | |
582 | buf->offset = 0; | |
583 | buf->len = chars; | |
923f4f23 IM |
584 | pipe->nrbufs = ++bufs; |
585 | pipe->tmp_page = NULL; | |
1da177e4 LT |
586 | |
587 | total_len -= chars; | |
588 | if (!total_len) | |
589 | break; | |
590 | } | |
35f3d14d | 591 | if (bufs < pipe->buffers) |
1da177e4 LT |
592 | continue; |
593 | if (filp->f_flags & O_NONBLOCK) { | |
341b446b IM |
594 | if (!ret) |
595 | ret = -EAGAIN; | |
1da177e4 LT |
596 | break; |
597 | } | |
598 | if (signal_pending(current)) { | |
341b446b IM |
599 | if (!ret) |
600 | ret = -ERESTARTSYS; | |
1da177e4 LT |
601 | break; |
602 | } | |
603 | if (do_wakeup) { | |
923f4f23 IM |
604 | wake_up_interruptible_sync(&pipe->wait); |
605 | kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); | |
1da177e4 LT |
606 | do_wakeup = 0; |
607 | } | |
923f4f23 IM |
608 | pipe->waiting_writers++; |
609 | pipe_wait(pipe); | |
610 | pipe->waiting_writers--; | |
1da177e4 LT |
611 | } |
612 | out: | |
9aeedfc4 | 613 | mutex_unlock(&inode->i_mutex); |
1da177e4 | 614 | if (do_wakeup) { |
71e20f18 | 615 | wake_up_interruptible_sync(&pipe->wait); |
923f4f23 | 616 | kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); |
1da177e4 LT |
617 | } |
618 | if (ret > 0) | |
870f4817 | 619 | file_update_time(filp); |
1da177e4 LT |
620 | return ret; |
621 | } | |
622 | ||
1da177e4 LT |
623 | static ssize_t |
624 | bad_pipe_r(struct file *filp, char __user *buf, size_t count, loff_t *ppos) | |
625 | { | |
626 | return -EBADF; | |
627 | } | |
628 | ||
629 | static ssize_t | |
341b446b IM |
630 | bad_pipe_w(struct file *filp, const char __user *buf, size_t count, |
631 | loff_t *ppos) | |
1da177e4 LT |
632 | { |
633 | return -EBADF; | |
634 | } | |
635 | ||
d59d0b1b | 636 | static long pipe_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) |
1da177e4 | 637 | { |
0f7fc9e4 | 638 | struct inode *inode = filp->f_path.dentry->d_inode; |
923f4f23 | 639 | struct pipe_inode_info *pipe; |
1da177e4 LT |
640 | int count, buf, nrbufs; |
641 | ||
642 | switch (cmd) { | |
643 | case FIONREAD: | |
9aeedfc4 | 644 | mutex_lock(&inode->i_mutex); |
923f4f23 | 645 | pipe = inode->i_pipe; |
1da177e4 | 646 | count = 0; |
923f4f23 IM |
647 | buf = pipe->curbuf; |
648 | nrbufs = pipe->nrbufs; | |
1da177e4 | 649 | while (--nrbufs >= 0) { |
923f4f23 | 650 | count += pipe->bufs[buf].len; |
35f3d14d | 651 | buf = (buf+1) & (pipe->buffers - 1); |
1da177e4 | 652 | } |
9aeedfc4 | 653 | mutex_unlock(&inode->i_mutex); |
923f4f23 | 654 | |
1da177e4 LT |
655 | return put_user(count, (int __user *)arg); |
656 | default: | |
657 | return -EINVAL; | |
658 | } | |
659 | } | |
660 | ||
661 | /* No kernel lock held - fine */ | |
662 | static unsigned int | |
663 | pipe_poll(struct file *filp, poll_table *wait) | |
664 | { | |
665 | unsigned int mask; | |
0f7fc9e4 | 666 | struct inode *inode = filp->f_path.dentry->d_inode; |
923f4f23 | 667 | struct pipe_inode_info *pipe = inode->i_pipe; |
1da177e4 LT |
668 | int nrbufs; |
669 | ||
923f4f23 | 670 | poll_wait(filp, &pipe->wait, wait); |
1da177e4 LT |
671 | |
672 | /* Reading only -- no need for acquiring the semaphore. */ | |
923f4f23 | 673 | nrbufs = pipe->nrbufs; |
1da177e4 LT |
674 | mask = 0; |
675 | if (filp->f_mode & FMODE_READ) { | |
676 | mask = (nrbufs > 0) ? POLLIN | POLLRDNORM : 0; | |
923f4f23 | 677 | if (!pipe->writers && filp->f_version != pipe->w_counter) |
1da177e4 LT |
678 | mask |= POLLHUP; |
679 | } | |
680 | ||
681 | if (filp->f_mode & FMODE_WRITE) { | |
35f3d14d | 682 | mask |= (nrbufs < pipe->buffers) ? POLLOUT | POLLWRNORM : 0; |
5e5d7a22 PE |
683 | /* |
684 | * Most Unices do not set POLLERR for FIFOs but on Linux they | |
685 | * behave exactly like pipes for poll(). | |
686 | */ | |
923f4f23 | 687 | if (!pipe->readers) |
1da177e4 LT |
688 | mask |= POLLERR; |
689 | } | |
690 | ||
691 | return mask; | |
692 | } | |
693 | ||
1da177e4 LT |
694 | static int |
695 | pipe_release(struct inode *inode, int decr, int decw) | |
696 | { | |
923f4f23 IM |
697 | struct pipe_inode_info *pipe; |
698 | ||
9aeedfc4 | 699 | mutex_lock(&inode->i_mutex); |
923f4f23 IM |
700 | pipe = inode->i_pipe; |
701 | pipe->readers -= decr; | |
702 | pipe->writers -= decw; | |
341b446b | 703 | |
923f4f23 | 704 | if (!pipe->readers && !pipe->writers) { |
1da177e4 LT |
705 | free_pipe_info(inode); |
706 | } else { | |
71e20f18 | 707 | wake_up_interruptible_sync(&pipe->wait); |
923f4f23 IM |
708 | kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); |
709 | kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); | |
1da177e4 | 710 | } |
9aeedfc4 | 711 | mutex_unlock(&inode->i_mutex); |
1da177e4 LT |
712 | |
713 | return 0; | |
714 | } | |
715 | ||
716 | static int | |
717 | pipe_read_fasync(int fd, struct file *filp, int on) | |
718 | { | |
0f7fc9e4 | 719 | struct inode *inode = filp->f_path.dentry->d_inode; |
1da177e4 LT |
720 | int retval; |
721 | ||
9aeedfc4 IM |
722 | mutex_lock(&inode->i_mutex); |
723 | retval = fasync_helper(fd, filp, on, &inode->i_pipe->fasync_readers); | |
724 | mutex_unlock(&inode->i_mutex); | |
1da177e4 | 725 | |
60aa4924 | 726 | return retval; |
1da177e4 LT |
727 | } |
728 | ||
729 | ||
730 | static int | |
731 | pipe_write_fasync(int fd, struct file *filp, int on) | |
732 | { | |
0f7fc9e4 | 733 | struct inode *inode = filp->f_path.dentry->d_inode; |
1da177e4 LT |
734 | int retval; |
735 | ||
9aeedfc4 IM |
736 | mutex_lock(&inode->i_mutex); |
737 | retval = fasync_helper(fd, filp, on, &inode->i_pipe->fasync_writers); | |
738 | mutex_unlock(&inode->i_mutex); | |
1da177e4 | 739 | |
60aa4924 | 740 | return retval; |
1da177e4 LT |
741 | } |
742 | ||
743 | ||
744 | static int | |
745 | pipe_rdwr_fasync(int fd, struct file *filp, int on) | |
746 | { | |
0f7fc9e4 | 747 | struct inode *inode = filp->f_path.dentry->d_inode; |
341b446b | 748 | struct pipe_inode_info *pipe = inode->i_pipe; |
1da177e4 LT |
749 | int retval; |
750 | ||
9aeedfc4 | 751 | mutex_lock(&inode->i_mutex); |
341b446b | 752 | retval = fasync_helper(fd, filp, on, &pipe->fasync_readers); |
e5bc49ba | 753 | if (retval >= 0) { |
341b446b | 754 | retval = fasync_helper(fd, filp, on, &pipe->fasync_writers); |
e5bc49ba ON |
755 | if (retval < 0) /* this can happen only if on == T */ |
756 | fasync_helper(-1, filp, 0, &pipe->fasync_readers); | |
757 | } | |
9aeedfc4 | 758 | mutex_unlock(&inode->i_mutex); |
60aa4924 | 759 | return retval; |
1da177e4 LT |
760 | } |
761 | ||
762 | ||
763 | static int | |
764 | pipe_read_release(struct inode *inode, struct file *filp) | |
765 | { | |
1da177e4 LT |
766 | return pipe_release(inode, 1, 0); |
767 | } | |
768 | ||
769 | static int | |
770 | pipe_write_release(struct inode *inode, struct file *filp) | |
771 | { | |
1da177e4 LT |
772 | return pipe_release(inode, 0, 1); |
773 | } | |
774 | ||
775 | static int | |
776 | pipe_rdwr_release(struct inode *inode, struct file *filp) | |
777 | { | |
778 | int decr, decw; | |
779 | ||
1da177e4 LT |
780 | decr = (filp->f_mode & FMODE_READ) != 0; |
781 | decw = (filp->f_mode & FMODE_WRITE) != 0; | |
782 | return pipe_release(inode, decr, decw); | |
783 | } | |
784 | ||
785 | static int | |
786 | pipe_read_open(struct inode *inode, struct file *filp) | |
787 | { | |
ad396024 EC |
788 | int ret = -ENOENT; |
789 | ||
9aeedfc4 | 790 | mutex_lock(&inode->i_mutex); |
ad396024 EC |
791 | |
792 | if (inode->i_pipe) { | |
793 | ret = 0; | |
794 | inode->i_pipe->readers++; | |
795 | } | |
796 | ||
9aeedfc4 | 797 | mutex_unlock(&inode->i_mutex); |
1da177e4 | 798 | |
ad396024 | 799 | return ret; |
1da177e4 LT |
800 | } |
801 | ||
802 | static int | |
803 | pipe_write_open(struct inode *inode, struct file *filp) | |
804 | { | |
ad396024 EC |
805 | int ret = -ENOENT; |
806 | ||
9aeedfc4 | 807 | mutex_lock(&inode->i_mutex); |
ad396024 EC |
808 | |
809 | if (inode->i_pipe) { | |
810 | ret = 0; | |
811 | inode->i_pipe->writers++; | |
812 | } | |
813 | ||
9aeedfc4 | 814 | mutex_unlock(&inode->i_mutex); |
1da177e4 | 815 | |
ad396024 | 816 | return ret; |
1da177e4 LT |
817 | } |
818 | ||
819 | static int | |
820 | pipe_rdwr_open(struct inode *inode, struct file *filp) | |
821 | { | |
ad396024 EC |
822 | int ret = -ENOENT; |
823 | ||
9aeedfc4 | 824 | mutex_lock(&inode->i_mutex); |
ad396024 EC |
825 | |
826 | if (inode->i_pipe) { | |
827 | ret = 0; | |
828 | if (filp->f_mode & FMODE_READ) | |
829 | inode->i_pipe->readers++; | |
830 | if (filp->f_mode & FMODE_WRITE) | |
831 | inode->i_pipe->writers++; | |
832 | } | |
833 | ||
9aeedfc4 | 834 | mutex_unlock(&inode->i_mutex); |
1da177e4 | 835 | |
ad396024 | 836 | return ret; |
1da177e4 LT |
837 | } |
838 | ||
839 | /* | |
840 | * The file_operations structs are not static because they | |
841 | * are also used in linux/fs/fifo.c to do operations on FIFOs. | |
d2d9648e DV |
842 | * |
843 | * Pipes reuse fifos' file_operations structs. | |
1da177e4 | 844 | */ |
d2d9648e | 845 | const struct file_operations read_pipefifo_fops = { |
1da177e4 | 846 | .llseek = no_llseek, |
ee0b3e67 BP |
847 | .read = do_sync_read, |
848 | .aio_read = pipe_read, | |
1da177e4 LT |
849 | .write = bad_pipe_w, |
850 | .poll = pipe_poll, | |
d59d0b1b | 851 | .unlocked_ioctl = pipe_ioctl, |
1da177e4 LT |
852 | .open = pipe_read_open, |
853 | .release = pipe_read_release, | |
854 | .fasync = pipe_read_fasync, | |
855 | }; | |
856 | ||
d2d9648e | 857 | const struct file_operations write_pipefifo_fops = { |
1da177e4 LT |
858 | .llseek = no_llseek, |
859 | .read = bad_pipe_r, | |
ee0b3e67 BP |
860 | .write = do_sync_write, |
861 | .aio_write = pipe_write, | |
1da177e4 | 862 | .poll = pipe_poll, |
d59d0b1b | 863 | .unlocked_ioctl = pipe_ioctl, |
1da177e4 LT |
864 | .open = pipe_write_open, |
865 | .release = pipe_write_release, | |
866 | .fasync = pipe_write_fasync, | |
867 | }; | |
868 | ||
d2d9648e | 869 | const struct file_operations rdwr_pipefifo_fops = { |
1da177e4 | 870 | .llseek = no_llseek, |
ee0b3e67 BP |
871 | .read = do_sync_read, |
872 | .aio_read = pipe_read, | |
873 | .write = do_sync_write, | |
874 | .aio_write = pipe_write, | |
1da177e4 | 875 | .poll = pipe_poll, |
d59d0b1b | 876 | .unlocked_ioctl = pipe_ioctl, |
1da177e4 LT |
877 | .open = pipe_rdwr_open, |
878 | .release = pipe_rdwr_release, | |
879 | .fasync = pipe_rdwr_fasync, | |
880 | }; | |
881 | ||
3a326a2c IM |
882 | struct pipe_inode_info * alloc_pipe_info(struct inode *inode) |
883 | { | |
923f4f23 | 884 | struct pipe_inode_info *pipe; |
3a326a2c | 885 | |
923f4f23 IM |
886 | pipe = kzalloc(sizeof(struct pipe_inode_info), GFP_KERNEL); |
887 | if (pipe) { | |
35f3d14d JA |
888 | pipe->bufs = kzalloc(sizeof(struct pipe_buffer) * PIPE_DEF_BUFFERS, GFP_KERNEL); |
889 | if (pipe->bufs) { | |
890 | init_waitqueue_head(&pipe->wait); | |
891 | pipe->r_counter = pipe->w_counter = 1; | |
892 | pipe->inode = inode; | |
893 | pipe->buffers = PIPE_DEF_BUFFERS; | |
894 | return pipe; | |
895 | } | |
896 | kfree(pipe); | |
3a326a2c IM |
897 | } |
898 | ||
35f3d14d | 899 | return NULL; |
3a326a2c IM |
900 | } |
901 | ||
923f4f23 | 902 | void __free_pipe_info(struct pipe_inode_info *pipe) |
1da177e4 LT |
903 | { |
904 | int i; | |
1da177e4 | 905 | |
35f3d14d | 906 | for (i = 0; i < pipe->buffers; i++) { |
923f4f23 | 907 | struct pipe_buffer *buf = pipe->bufs + i; |
1da177e4 | 908 | if (buf->ops) |
923f4f23 | 909 | buf->ops->release(pipe, buf); |
1da177e4 | 910 | } |
923f4f23 IM |
911 | if (pipe->tmp_page) |
912 | __free_page(pipe->tmp_page); | |
35f3d14d | 913 | kfree(pipe->bufs); |
923f4f23 | 914 | kfree(pipe); |
1da177e4 LT |
915 | } |
916 | ||
b92ce558 JA |
917 | void free_pipe_info(struct inode *inode) |
918 | { | |
919 | __free_pipe_info(inode->i_pipe); | |
920 | inode->i_pipe = NULL; | |
921 | } | |
922 | ||
fa3536cc | 923 | static struct vfsmount *pipe_mnt __read_mostly; |
341b446b | 924 | |
c23fbb6b ED |
925 | /* |
926 | * pipefs_dname() is called from d_path(). | |
927 | */ | |
928 | static char *pipefs_dname(struct dentry *dentry, char *buffer, int buflen) | |
929 | { | |
930 | return dynamic_dname(dentry, buffer, buflen, "pipe:[%lu]", | |
931 | dentry->d_inode->i_ino); | |
932 | } | |
933 | ||
3ba13d17 | 934 | static const struct dentry_operations pipefs_dentry_operations = { |
c23fbb6b | 935 | .d_dname = pipefs_dname, |
1da177e4 LT |
936 | }; |
937 | ||
938 | static struct inode * get_pipe_inode(void) | |
939 | { | |
940 | struct inode *inode = new_inode(pipe_mnt->mnt_sb); | |
923f4f23 | 941 | struct pipe_inode_info *pipe; |
1da177e4 LT |
942 | |
943 | if (!inode) | |
944 | goto fail_inode; | |
945 | ||
923f4f23 IM |
946 | pipe = alloc_pipe_info(inode); |
947 | if (!pipe) | |
1da177e4 | 948 | goto fail_iput; |
923f4f23 | 949 | inode->i_pipe = pipe; |
3a326a2c | 950 | |
923f4f23 | 951 | pipe->readers = pipe->writers = 1; |
d2d9648e | 952 | inode->i_fop = &rdwr_pipefifo_fops; |
1da177e4 LT |
953 | |
954 | /* | |
955 | * Mark the inode dirty from the very beginning, | |
956 | * that way it will never be moved to the dirty | |
957 | * list because "mark_inode_dirty()" will think | |
958 | * that it already _is_ on the dirty list. | |
959 | */ | |
960 | inode->i_state = I_DIRTY; | |
961 | inode->i_mode = S_IFIFO | S_IRUSR | S_IWUSR; | |
da9592ed DH |
962 | inode->i_uid = current_fsuid(); |
963 | inode->i_gid = current_fsgid(); | |
1da177e4 | 964 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; |
923f4f23 | 965 | |
1da177e4 LT |
966 | return inode; |
967 | ||
968 | fail_iput: | |
969 | iput(inode); | |
341b446b | 970 | |
1da177e4 LT |
971 | fail_inode: |
972 | return NULL; | |
973 | } | |
974 | ||
be61a86d | 975 | struct file *create_write_pipe(int flags) |
1da177e4 | 976 | { |
d6cbd281 AK |
977 | int err; |
978 | struct inode *inode; | |
979 | struct file *f; | |
2c48b9c4 | 980 | struct path path; |
c23fbb6b | 981 | struct qstr name = { .name = "" }; |
1da177e4 | 982 | |
d6cbd281 | 983 | err = -ENFILE; |
1da177e4 LT |
984 | inode = get_pipe_inode(); |
985 | if (!inode) | |
430e285e | 986 | goto err; |
1da177e4 | 987 | |
d6cbd281 | 988 | err = -ENOMEM; |
2c48b9c4 AV |
989 | path.dentry = d_alloc(pipe_mnt->mnt_sb->s_root, &name); |
990 | if (!path.dentry) | |
d6cbd281 | 991 | goto err_inode; |
2c48b9c4 | 992 | path.mnt = mntget(pipe_mnt); |
341b446b | 993 | |
2c48b9c4 | 994 | path.dentry->d_op = &pipefs_dentry_operations; |
2c48b9c4 | 995 | d_instantiate(path.dentry, inode); |
430e285e DH |
996 | |
997 | err = -ENFILE; | |
2c48b9c4 | 998 | f = alloc_file(&path, FMODE_WRITE, &write_pipefifo_fops); |
430e285e DH |
999 | if (!f) |
1000 | goto err_dentry; | |
d6cbd281 | 1001 | f->f_mapping = inode->i_mapping; |
341b446b | 1002 | |
be61a86d | 1003 | f->f_flags = O_WRONLY | (flags & O_NONBLOCK); |
d6cbd281 AK |
1004 | f->f_version = 0; |
1005 | ||
1006 | return f; | |
1da177e4 | 1007 | |
430e285e | 1008 | err_dentry: |
ed152437 | 1009 | free_pipe_info(inode); |
2c48b9c4 | 1010 | path_put(&path); |
ed152437 AV |
1011 | return ERR_PTR(err); |
1012 | ||
d6cbd281 | 1013 | err_inode: |
1da177e4 LT |
1014 | free_pipe_info(inode); |
1015 | iput(inode); | |
430e285e | 1016 | err: |
d6cbd281 AK |
1017 | return ERR_PTR(err); |
1018 | } | |
1019 | ||
1020 | void free_write_pipe(struct file *f) | |
1021 | { | |
5ccac88e | 1022 | free_pipe_info(f->f_dentry->d_inode); |
c8e7f449 | 1023 | path_put(&f->f_path); |
d6cbd281 AK |
1024 | put_filp(f); |
1025 | } | |
1026 | ||
be61a86d | 1027 | struct file *create_read_pipe(struct file *wrf, int flags) |
d6cbd281 | 1028 | { |
d231412d AV |
1029 | /* Grab pipe from the writer */ |
1030 | struct file *f = alloc_file(&wrf->f_path, FMODE_READ, | |
1031 | &read_pipefifo_fops); | |
d6cbd281 AK |
1032 | if (!f) |
1033 | return ERR_PTR(-ENFILE); | |
1034 | ||
c8e7f449 | 1035 | path_get(&wrf->f_path); |
be61a86d | 1036 | f->f_flags = O_RDONLY | (flags & O_NONBLOCK); |
d6cbd281 AK |
1037 | |
1038 | return f; | |
1039 | } | |
1040 | ||
ed8cae8b | 1041 | int do_pipe_flags(int *fd, int flags) |
d6cbd281 AK |
1042 | { |
1043 | struct file *fw, *fr; | |
1044 | int error; | |
1045 | int fdw, fdr; | |
1046 | ||
be61a86d | 1047 | if (flags & ~(O_CLOEXEC | O_NONBLOCK)) |
ed8cae8b UD |
1048 | return -EINVAL; |
1049 | ||
be61a86d | 1050 | fw = create_write_pipe(flags); |
d6cbd281 AK |
1051 | if (IS_ERR(fw)) |
1052 | return PTR_ERR(fw); | |
be61a86d | 1053 | fr = create_read_pipe(fw, flags); |
d6cbd281 AK |
1054 | error = PTR_ERR(fr); |
1055 | if (IS_ERR(fr)) | |
1056 | goto err_write_pipe; | |
1057 | ||
ed8cae8b | 1058 | error = get_unused_fd_flags(flags); |
d6cbd281 AK |
1059 | if (error < 0) |
1060 | goto err_read_pipe; | |
1061 | fdr = error; | |
1062 | ||
ed8cae8b | 1063 | error = get_unused_fd_flags(flags); |
d6cbd281 AK |
1064 | if (error < 0) |
1065 | goto err_fdr; | |
1066 | fdw = error; | |
1067 | ||
157cf649 | 1068 | audit_fd_pair(fdr, fdw); |
d6cbd281 AK |
1069 | fd_install(fdr, fr); |
1070 | fd_install(fdw, fw); | |
1071 | fd[0] = fdr; | |
1072 | fd[1] = fdw; | |
1073 | ||
1074 | return 0; | |
1075 | ||
1076 | err_fdr: | |
1077 | put_unused_fd(fdr); | |
1078 | err_read_pipe: | |
c8e7f449 | 1079 | path_put(&fr->f_path); |
d6cbd281 AK |
1080 | put_filp(fr); |
1081 | err_write_pipe: | |
1082 | free_write_pipe(fw); | |
1083 | return error; | |
1da177e4 LT |
1084 | } |
1085 | ||
d35c7b0e UD |
1086 | /* |
1087 | * sys_pipe() is the normal C calling standard for creating | |
1088 | * a pipe. It's not the way Unix traditionally does this, though. | |
1089 | */ | |
d4e82042 | 1090 | SYSCALL_DEFINE2(pipe2, int __user *, fildes, int, flags) |
d35c7b0e UD |
1091 | { |
1092 | int fd[2]; | |
1093 | int error; | |
1094 | ||
ed8cae8b | 1095 | error = do_pipe_flags(fd, flags); |
d35c7b0e | 1096 | if (!error) { |
ba719bae UD |
1097 | if (copy_to_user(fildes, fd, sizeof(fd))) { |
1098 | sys_close(fd[0]); | |
1099 | sys_close(fd[1]); | |
d35c7b0e | 1100 | error = -EFAULT; |
ba719bae | 1101 | } |
d35c7b0e UD |
1102 | } |
1103 | return error; | |
1104 | } | |
1105 | ||
2b664219 | 1106 | SYSCALL_DEFINE1(pipe, int __user *, fildes) |
ed8cae8b UD |
1107 | { |
1108 | return sys_pipe2(fildes, 0); | |
1109 | } | |
1110 | ||
35f3d14d JA |
1111 | /* |
1112 | * Allocate a new array of pipe buffers and copy the info over. Returns the | |
1113 | * pipe size if successful, or return -ERROR on error. | |
1114 | */ | |
1115 | static long pipe_set_size(struct pipe_inode_info *pipe, unsigned long arg) | |
1116 | { | |
1117 | struct pipe_buffer *bufs; | |
1118 | ||
1119 | /* | |
1120 | * Must be a power-of-2 currently | |
1121 | */ | |
1122 | if (!is_power_of_2(arg)) | |
1123 | return -EINVAL; | |
1124 | ||
1125 | /* | |
1126 | * We can shrink the pipe, if arg >= pipe->nrbufs. Since we don't | |
1127 | * expect a lot of shrink+grow operations, just free and allocate | |
1128 | * again like we would do for growing. If the pipe currently | |
1129 | * contains more buffers than arg, then return busy. | |
1130 | */ | |
1131 | if (arg < pipe->nrbufs) | |
1132 | return -EBUSY; | |
1133 | ||
1134 | bufs = kcalloc(arg, sizeof(struct pipe_buffer), GFP_KERNEL); | |
1135 | if (unlikely(!bufs)) | |
1136 | return -ENOMEM; | |
1137 | ||
1138 | /* | |
1139 | * The pipe array wraps around, so just start the new one at zero | |
1140 | * and adjust the indexes. | |
1141 | */ | |
1142 | if (pipe->nrbufs) { | |
1143 | const unsigned int tail = pipe->nrbufs & (pipe->buffers - 1); | |
1144 | const unsigned int head = pipe->nrbufs - tail; | |
1145 | ||
1146 | if (head) | |
1147 | memcpy(bufs, pipe->bufs + pipe->curbuf, head * sizeof(struct pipe_buffer)); | |
1148 | if (tail) | |
1149 | memcpy(bufs + head, pipe->bufs + pipe->curbuf, tail * sizeof(struct pipe_buffer)); | |
1150 | } | |
1151 | ||
1152 | pipe->curbuf = 0; | |
1153 | kfree(pipe->bufs); | |
1154 | pipe->bufs = bufs; | |
1155 | pipe->buffers = arg; | |
1156 | return arg; | |
1157 | } | |
1158 | ||
1159 | long pipe_fcntl(struct file *file, unsigned int cmd, unsigned long arg) | |
1160 | { | |
1161 | struct pipe_inode_info *pipe; | |
1162 | long ret; | |
1163 | ||
1164 | pipe = file->f_path.dentry->d_inode->i_pipe; | |
1165 | if (!pipe) | |
1166 | return -EBADF; | |
1167 | ||
1168 | mutex_lock(&pipe->inode->i_mutex); | |
1169 | ||
1170 | switch (cmd) { | |
1171 | case F_SETPIPE_SZ: | |
b492e95b JA |
1172 | if (!capable(CAP_SYS_ADMIN) && arg > pipe_max_pages) |
1173 | return -EINVAL; | |
1174 | /* | |
1175 | * The pipe needs to be at least 2 pages large to | |
1176 | * guarantee POSIX behaviour. | |
1177 | */ | |
1178 | if (arg < 2) | |
1179 | return -EINVAL; | |
35f3d14d JA |
1180 | ret = pipe_set_size(pipe, arg); |
1181 | break; | |
1182 | case F_GETPIPE_SZ: | |
1183 | ret = pipe->buffers; | |
1184 | break; | |
1185 | default: | |
1186 | ret = -EINVAL; | |
1187 | break; | |
1188 | } | |
1189 | ||
1190 | mutex_unlock(&pipe->inode->i_mutex); | |
1191 | return ret; | |
1192 | } | |
1193 | ||
1da177e4 LT |
1194 | /* |
1195 | * pipefs should _never_ be mounted by userland - too much of security hassle, | |
1196 | * no real gain from having the whole whorehouse mounted. So we don't need | |
1197 | * any operations on the root directory. However, we need a non-trivial | |
1198 | * d_name - pipe: will go nicely and kill the special-casing in procfs. | |
1199 | */ | |
454e2398 DH |
1200 | static int pipefs_get_sb(struct file_system_type *fs_type, |
1201 | int flags, const char *dev_name, void *data, | |
1202 | struct vfsmount *mnt) | |
1da177e4 | 1203 | { |
454e2398 | 1204 | return get_sb_pseudo(fs_type, "pipe:", NULL, PIPEFS_MAGIC, mnt); |
1da177e4 LT |
1205 | } |
1206 | ||
1207 | static struct file_system_type pipe_fs_type = { | |
1208 | .name = "pipefs", | |
1209 | .get_sb = pipefs_get_sb, | |
1210 | .kill_sb = kill_anon_super, | |
1211 | }; | |
1212 | ||
1213 | static int __init init_pipe_fs(void) | |
1214 | { | |
1215 | int err = register_filesystem(&pipe_fs_type); | |
341b446b | 1216 | |
1da177e4 LT |
1217 | if (!err) { |
1218 | pipe_mnt = kern_mount(&pipe_fs_type); | |
1219 | if (IS_ERR(pipe_mnt)) { | |
1220 | err = PTR_ERR(pipe_mnt); | |
1221 | unregister_filesystem(&pipe_fs_type); | |
1222 | } | |
1223 | } | |
1224 | return err; | |
1225 | } | |
1226 | ||
1227 | static void __exit exit_pipe_fs(void) | |
1228 | { | |
1229 | unregister_filesystem(&pipe_fs_type); | |
1230 | mntput(pipe_mnt); | |
1231 | } | |
1232 | ||
1233 | fs_initcall(init_pipe_fs); | |
1234 | module_exit(exit_pipe_fs); |