Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * linux/fs/pipe.c | |
3 | * | |
4 | * Copyright (C) 1991, 1992, 1999 Linus Torvalds | |
5 | */ | |
6 | ||
7 | #include <linux/mm.h> | |
8 | #include <linux/file.h> | |
9 | #include <linux/poll.h> | |
10 | #include <linux/slab.h> | |
11 | #include <linux/module.h> | |
12 | #include <linux/init.h> | |
13 | #include <linux/fs.h> | |
14 | #include <linux/mount.h> | |
15 | #include <linux/pipe_fs_i.h> | |
16 | #include <linux/uio.h> | |
17 | #include <linux/highmem.h> | |
18 | ||
19 | #include <asm/uaccess.h> | |
20 | #include <asm/ioctls.h> | |
21 | ||
22 | /* | |
23 | * We use a start+len construction, which provides full use of the | |
24 | * allocated memory. | |
25 | * -- Florian Coosmann (FGC) | |
26 | * | |
27 | * Reads with count = 0 should always return 0. | |
28 | * -- Julian Bradfield 1999-06-07. | |
29 | * | |
30 | * FIFOs and Pipes now generate SIGIO for both readers and writers. | |
31 | * -- Jeremy Elson <jelson@circlemud.org> 2001-08-16 | |
32 | * | |
33 | * pipe_read & write cleanup | |
34 | * -- Manfred Spraul <manfred@colorfullife.com> 2002-05-09 | |
35 | */ | |
36 | ||
37 | /* Drop the inode semaphore and wait for a pipe event, atomically */ | |
38 | void pipe_wait(struct inode * inode) | |
39 | { | |
40 | DEFINE_WAIT(wait); | |
41 | ||
42 | prepare_to_wait(PIPE_WAIT(*inode), &wait, TASK_INTERRUPTIBLE); | |
43 | up(PIPE_SEM(*inode)); | |
44 | schedule(); | |
45 | finish_wait(PIPE_WAIT(*inode), &wait); | |
46 | down(PIPE_SEM(*inode)); | |
47 | } | |
48 | ||
49 | static inline int | |
50 | pipe_iov_copy_from_user(void *to, struct iovec *iov, unsigned long len) | |
51 | { | |
52 | unsigned long copy; | |
53 | ||
54 | while (len > 0) { | |
55 | while (!iov->iov_len) | |
56 | iov++; | |
57 | copy = min_t(unsigned long, len, iov->iov_len); | |
58 | ||
59 | if (copy_from_user(to, iov->iov_base, copy)) | |
60 | return -EFAULT; | |
61 | to += copy; | |
62 | len -= copy; | |
63 | iov->iov_base += copy; | |
64 | iov->iov_len -= copy; | |
65 | } | |
66 | return 0; | |
67 | } | |
68 | ||
69 | static inline int | |
70 | pipe_iov_copy_to_user(struct iovec *iov, const void *from, unsigned long len) | |
71 | { | |
72 | unsigned long copy; | |
73 | ||
74 | while (len > 0) { | |
75 | while (!iov->iov_len) | |
76 | iov++; | |
77 | copy = min_t(unsigned long, len, iov->iov_len); | |
78 | ||
79 | if (copy_to_user(iov->iov_base, from, copy)) | |
80 | return -EFAULT; | |
81 | from += copy; | |
82 | len -= copy; | |
83 | iov->iov_base += copy; | |
84 | iov->iov_len -= copy; | |
85 | } | |
86 | return 0; | |
87 | } | |
88 | ||
89 | static void anon_pipe_buf_release(struct pipe_inode_info *info, struct pipe_buffer *buf) | |
90 | { | |
91 | struct page *page = buf->page; | |
92 | ||
93 | if (info->tmp_page) { | |
94 | __free_page(page); | |
95 | return; | |
96 | } | |
97 | info->tmp_page = page; | |
98 | } | |
99 | ||
100 | static void *anon_pipe_buf_map(struct file *file, struct pipe_inode_info *info, struct pipe_buffer *buf) | |
101 | { | |
102 | return kmap(buf->page); | |
103 | } | |
104 | ||
105 | static void anon_pipe_buf_unmap(struct pipe_inode_info *info, struct pipe_buffer *buf) | |
106 | { | |
107 | kunmap(buf->page); | |
108 | } | |
109 | ||
110 | static struct pipe_buf_operations anon_pipe_buf_ops = { | |
111 | .can_merge = 1, | |
112 | .map = anon_pipe_buf_map, | |
113 | .unmap = anon_pipe_buf_unmap, | |
114 | .release = anon_pipe_buf_release, | |
115 | }; | |
116 | ||
117 | static ssize_t | |
118 | pipe_readv(struct file *filp, const struct iovec *_iov, | |
119 | unsigned long nr_segs, loff_t *ppos) | |
120 | { | |
121 | struct inode *inode = filp->f_dentry->d_inode; | |
122 | struct pipe_inode_info *info; | |
123 | int do_wakeup; | |
124 | ssize_t ret; | |
125 | struct iovec *iov = (struct iovec *)_iov; | |
126 | size_t total_len; | |
127 | ||
128 | total_len = iov_length(iov, nr_segs); | |
129 | /* Null read succeeds. */ | |
130 | if (unlikely(total_len == 0)) | |
131 | return 0; | |
132 | ||
133 | do_wakeup = 0; | |
134 | ret = 0; | |
135 | down(PIPE_SEM(*inode)); | |
136 | info = inode->i_pipe; | |
137 | for (;;) { | |
138 | int bufs = info->nrbufs; | |
139 | if (bufs) { | |
140 | int curbuf = info->curbuf; | |
141 | struct pipe_buffer *buf = info->bufs + curbuf; | |
142 | struct pipe_buf_operations *ops = buf->ops; | |
143 | void *addr; | |
144 | size_t chars = buf->len; | |
145 | int error; | |
146 | ||
147 | if (chars > total_len) | |
148 | chars = total_len; | |
149 | ||
150 | addr = ops->map(filp, info, buf); | |
151 | error = pipe_iov_copy_to_user(iov, addr + buf->offset, chars); | |
152 | ops->unmap(info, buf); | |
153 | if (unlikely(error)) { | |
154 | if (!ret) ret = -EFAULT; | |
155 | break; | |
156 | } | |
157 | ret += chars; | |
158 | buf->offset += chars; | |
159 | buf->len -= chars; | |
160 | if (!buf->len) { | |
161 | buf->ops = NULL; | |
162 | ops->release(info, buf); | |
163 | curbuf = (curbuf + 1) & (PIPE_BUFFERS-1); | |
164 | info->curbuf = curbuf; | |
165 | info->nrbufs = --bufs; | |
166 | do_wakeup = 1; | |
167 | } | |
168 | total_len -= chars; | |
169 | if (!total_len) | |
170 | break; /* common path: read succeeded */ | |
171 | } | |
172 | if (bufs) /* More to do? */ | |
173 | continue; | |
174 | if (!PIPE_WRITERS(*inode)) | |
175 | break; | |
176 | if (!PIPE_WAITING_WRITERS(*inode)) { | |
177 | /* syscall merging: Usually we must not sleep | |
178 | * if O_NONBLOCK is set, or if we got some data. | |
179 | * But if a writer sleeps in kernel space, then | |
180 | * we can wait for that data without violating POSIX. | |
181 | */ | |
182 | if (ret) | |
183 | break; | |
184 | if (filp->f_flags & O_NONBLOCK) { | |
185 | ret = -EAGAIN; | |
186 | break; | |
187 | } | |
188 | } | |
189 | if (signal_pending(current)) { | |
190 | if (!ret) ret = -ERESTARTSYS; | |
191 | break; | |
192 | } | |
193 | if (do_wakeup) { | |
194 | wake_up_interruptible_sync(PIPE_WAIT(*inode)); | |
195 | kill_fasync(PIPE_FASYNC_WRITERS(*inode), SIGIO, POLL_OUT); | |
196 | } | |
197 | pipe_wait(inode); | |
198 | } | |
199 | up(PIPE_SEM(*inode)); | |
200 | /* Signal writers asynchronously that there is more room. */ | |
201 | if (do_wakeup) { | |
202 | wake_up_interruptible(PIPE_WAIT(*inode)); | |
203 | kill_fasync(PIPE_FASYNC_WRITERS(*inode), SIGIO, POLL_OUT); | |
204 | } | |
205 | if (ret > 0) | |
206 | file_accessed(filp); | |
207 | return ret; | |
208 | } | |
209 | ||
210 | static ssize_t | |
211 | pipe_read(struct file *filp, char __user *buf, size_t count, loff_t *ppos) | |
212 | { | |
213 | struct iovec iov = { .iov_base = buf, .iov_len = count }; | |
214 | return pipe_readv(filp, &iov, 1, ppos); | |
215 | } | |
216 | ||
217 | static ssize_t | |
218 | pipe_writev(struct file *filp, const struct iovec *_iov, | |
219 | unsigned long nr_segs, loff_t *ppos) | |
220 | { | |
221 | struct inode *inode = filp->f_dentry->d_inode; | |
222 | struct pipe_inode_info *info; | |
223 | ssize_t ret; | |
224 | int do_wakeup; | |
225 | struct iovec *iov = (struct iovec *)_iov; | |
226 | size_t total_len; | |
227 | ssize_t chars; | |
228 | ||
229 | total_len = iov_length(iov, nr_segs); | |
230 | /* Null write succeeds. */ | |
231 | if (unlikely(total_len == 0)) | |
232 | return 0; | |
233 | ||
234 | do_wakeup = 0; | |
235 | ret = 0; | |
236 | down(PIPE_SEM(*inode)); | |
237 | info = inode->i_pipe; | |
238 | ||
239 | if (!PIPE_READERS(*inode)) { | |
240 | send_sig(SIGPIPE, current, 0); | |
241 | ret = -EPIPE; | |
242 | goto out; | |
243 | } | |
244 | ||
245 | /* We try to merge small writes */ | |
246 | chars = total_len & (PAGE_SIZE-1); /* size of the last buffer */ | |
247 | if (info->nrbufs && chars != 0) { | |
248 | int lastbuf = (info->curbuf + info->nrbufs - 1) & (PIPE_BUFFERS-1); | |
249 | struct pipe_buffer *buf = info->bufs + lastbuf; | |
250 | struct pipe_buf_operations *ops = buf->ops; | |
251 | int offset = buf->offset + buf->len; | |
252 | if (ops->can_merge && offset + chars <= PAGE_SIZE) { | |
253 | void *addr = ops->map(filp, info, buf); | |
254 | int error = pipe_iov_copy_from_user(offset + addr, iov, chars); | |
255 | ops->unmap(info, buf); | |
256 | ret = error; | |
257 | do_wakeup = 1; | |
258 | if (error) | |
259 | goto out; | |
260 | buf->len += chars; | |
261 | total_len -= chars; | |
262 | ret = chars; | |
263 | if (!total_len) | |
264 | goto out; | |
265 | } | |
266 | } | |
267 | ||
268 | for (;;) { | |
269 | int bufs; | |
270 | if (!PIPE_READERS(*inode)) { | |
271 | send_sig(SIGPIPE, current, 0); | |
272 | if (!ret) ret = -EPIPE; | |
273 | break; | |
274 | } | |
275 | bufs = info->nrbufs; | |
276 | if (bufs < PIPE_BUFFERS) { | |
277 | int newbuf = (info->curbuf + bufs) & (PIPE_BUFFERS-1); | |
278 | struct pipe_buffer *buf = info->bufs + newbuf; | |
279 | struct page *page = info->tmp_page; | |
280 | int error; | |
281 | ||
282 | if (!page) { | |
283 | page = alloc_page(GFP_HIGHUSER); | |
284 | if (unlikely(!page)) { | |
285 | ret = ret ? : -ENOMEM; | |
286 | break; | |
287 | } | |
288 | info->tmp_page = page; | |
289 | } | |
290 | /* Always wakeup, even if the copy fails. Otherwise | |
291 | * we lock up (O_NONBLOCK-)readers that sleep due to | |
292 | * syscall merging. | |
293 | * FIXME! Is this really true? | |
294 | */ | |
295 | do_wakeup = 1; | |
296 | chars = PAGE_SIZE; | |
297 | if (chars > total_len) | |
298 | chars = total_len; | |
299 | ||
300 | error = pipe_iov_copy_from_user(kmap(page), iov, chars); | |
301 | kunmap(page); | |
302 | if (unlikely(error)) { | |
303 | if (!ret) ret = -EFAULT; | |
304 | break; | |
305 | } | |
306 | ret += chars; | |
307 | ||
308 | /* Insert it into the buffer array */ | |
309 | buf->page = page; | |
310 | buf->ops = &anon_pipe_buf_ops; | |
311 | buf->offset = 0; | |
312 | buf->len = chars; | |
313 | info->nrbufs = ++bufs; | |
314 | info->tmp_page = NULL; | |
315 | ||
316 | total_len -= chars; | |
317 | if (!total_len) | |
318 | break; | |
319 | } | |
320 | if (bufs < PIPE_BUFFERS) | |
321 | continue; | |
322 | if (filp->f_flags & O_NONBLOCK) { | |
323 | if (!ret) ret = -EAGAIN; | |
324 | break; | |
325 | } | |
326 | if (signal_pending(current)) { | |
327 | if (!ret) ret = -ERESTARTSYS; | |
328 | break; | |
329 | } | |
330 | if (do_wakeup) { | |
331 | wake_up_interruptible_sync(PIPE_WAIT(*inode)); | |
332 | kill_fasync(PIPE_FASYNC_READERS(*inode), SIGIO, POLL_IN); | |
333 | do_wakeup = 0; | |
334 | } | |
335 | PIPE_WAITING_WRITERS(*inode)++; | |
336 | pipe_wait(inode); | |
337 | PIPE_WAITING_WRITERS(*inode)--; | |
338 | } | |
339 | out: | |
340 | up(PIPE_SEM(*inode)); | |
341 | if (do_wakeup) { | |
342 | wake_up_interruptible(PIPE_WAIT(*inode)); | |
343 | kill_fasync(PIPE_FASYNC_READERS(*inode), SIGIO, POLL_IN); | |
344 | } | |
345 | if (ret > 0) | |
346 | inode_update_time(inode, 1); /* mtime and ctime */ | |
347 | return ret; | |
348 | } | |
349 | ||
350 | static ssize_t | |
351 | pipe_write(struct file *filp, const char __user *buf, | |
352 | size_t count, loff_t *ppos) | |
353 | { | |
354 | struct iovec iov = { .iov_base = (void __user *)buf, .iov_len = count }; | |
355 | return pipe_writev(filp, &iov, 1, ppos); | |
356 | } | |
357 | ||
358 | static ssize_t | |
359 | bad_pipe_r(struct file *filp, char __user *buf, size_t count, loff_t *ppos) | |
360 | { | |
361 | return -EBADF; | |
362 | } | |
363 | ||
364 | static ssize_t | |
365 | bad_pipe_w(struct file *filp, const char __user *buf, size_t count, loff_t *ppos) | |
366 | { | |
367 | return -EBADF; | |
368 | } | |
369 | ||
370 | static int | |
371 | pipe_ioctl(struct inode *pino, struct file *filp, | |
372 | unsigned int cmd, unsigned long arg) | |
373 | { | |
374 | struct inode *inode = filp->f_dentry->d_inode; | |
375 | struct pipe_inode_info *info; | |
376 | int count, buf, nrbufs; | |
377 | ||
378 | switch (cmd) { | |
379 | case FIONREAD: | |
380 | down(PIPE_SEM(*inode)); | |
381 | info = inode->i_pipe; | |
382 | count = 0; | |
383 | buf = info->curbuf; | |
384 | nrbufs = info->nrbufs; | |
385 | while (--nrbufs >= 0) { | |
386 | count += info->bufs[buf].len; | |
387 | buf = (buf+1) & (PIPE_BUFFERS-1); | |
388 | } | |
389 | up(PIPE_SEM(*inode)); | |
390 | return put_user(count, (int __user *)arg); | |
391 | default: | |
392 | return -EINVAL; | |
393 | } | |
394 | } | |
395 | ||
396 | /* No kernel lock held - fine */ | |
397 | static unsigned int | |
398 | pipe_poll(struct file *filp, poll_table *wait) | |
399 | { | |
400 | unsigned int mask; | |
401 | struct inode *inode = filp->f_dentry->d_inode; | |
402 | struct pipe_inode_info *info = inode->i_pipe; | |
403 | int nrbufs; | |
404 | ||
405 | poll_wait(filp, PIPE_WAIT(*inode), wait); | |
406 | ||
407 | /* Reading only -- no need for acquiring the semaphore. */ | |
408 | nrbufs = info->nrbufs; | |
409 | mask = 0; | |
410 | if (filp->f_mode & FMODE_READ) { | |
411 | mask = (nrbufs > 0) ? POLLIN | POLLRDNORM : 0; | |
412 | if (!PIPE_WRITERS(*inode) && filp->f_version != PIPE_WCOUNTER(*inode)) | |
413 | mask |= POLLHUP; | |
414 | } | |
415 | ||
416 | if (filp->f_mode & FMODE_WRITE) { | |
417 | mask |= (nrbufs < PIPE_BUFFERS) ? POLLOUT | POLLWRNORM : 0; | |
418 | if (!PIPE_READERS(*inode)) | |
419 | mask |= POLLERR; | |
420 | } | |
421 | ||
422 | return mask; | |
423 | } | |
424 | ||
425 | /* FIXME: most Unices do not set POLLERR for fifos */ | |
426 | #define fifo_poll pipe_poll | |
427 | ||
428 | static int | |
429 | pipe_release(struct inode *inode, int decr, int decw) | |
430 | { | |
431 | down(PIPE_SEM(*inode)); | |
432 | PIPE_READERS(*inode) -= decr; | |
433 | PIPE_WRITERS(*inode) -= decw; | |
434 | if (!PIPE_READERS(*inode) && !PIPE_WRITERS(*inode)) { | |
435 | free_pipe_info(inode); | |
436 | } else { | |
437 | wake_up_interruptible(PIPE_WAIT(*inode)); | |
438 | kill_fasync(PIPE_FASYNC_READERS(*inode), SIGIO, POLL_IN); | |
439 | kill_fasync(PIPE_FASYNC_WRITERS(*inode), SIGIO, POLL_OUT); | |
440 | } | |
441 | up(PIPE_SEM(*inode)); | |
442 | ||
443 | return 0; | |
444 | } | |
445 | ||
446 | static int | |
447 | pipe_read_fasync(int fd, struct file *filp, int on) | |
448 | { | |
449 | struct inode *inode = filp->f_dentry->d_inode; | |
450 | int retval; | |
451 | ||
452 | down(PIPE_SEM(*inode)); | |
453 | retval = fasync_helper(fd, filp, on, PIPE_FASYNC_READERS(*inode)); | |
454 | up(PIPE_SEM(*inode)); | |
455 | ||
456 | if (retval < 0) | |
457 | return retval; | |
458 | ||
459 | return 0; | |
460 | } | |
461 | ||
462 | ||
463 | static int | |
464 | pipe_write_fasync(int fd, struct file *filp, int on) | |
465 | { | |
466 | struct inode *inode = filp->f_dentry->d_inode; | |
467 | int retval; | |
468 | ||
469 | down(PIPE_SEM(*inode)); | |
470 | retval = fasync_helper(fd, filp, on, PIPE_FASYNC_WRITERS(*inode)); | |
471 | up(PIPE_SEM(*inode)); | |
472 | ||
473 | if (retval < 0) | |
474 | return retval; | |
475 | ||
476 | return 0; | |
477 | } | |
478 | ||
479 | ||
480 | static int | |
481 | pipe_rdwr_fasync(int fd, struct file *filp, int on) | |
482 | { | |
483 | struct inode *inode = filp->f_dentry->d_inode; | |
484 | int retval; | |
485 | ||
486 | down(PIPE_SEM(*inode)); | |
487 | ||
488 | retval = fasync_helper(fd, filp, on, PIPE_FASYNC_READERS(*inode)); | |
489 | ||
490 | if (retval >= 0) | |
491 | retval = fasync_helper(fd, filp, on, PIPE_FASYNC_WRITERS(*inode)); | |
492 | ||
493 | up(PIPE_SEM(*inode)); | |
494 | ||
495 | if (retval < 0) | |
496 | return retval; | |
497 | ||
498 | return 0; | |
499 | } | |
500 | ||
501 | ||
502 | static int | |
503 | pipe_read_release(struct inode *inode, struct file *filp) | |
504 | { | |
505 | pipe_read_fasync(-1, filp, 0); | |
506 | return pipe_release(inode, 1, 0); | |
507 | } | |
508 | ||
509 | static int | |
510 | pipe_write_release(struct inode *inode, struct file *filp) | |
511 | { | |
512 | pipe_write_fasync(-1, filp, 0); | |
513 | return pipe_release(inode, 0, 1); | |
514 | } | |
515 | ||
516 | static int | |
517 | pipe_rdwr_release(struct inode *inode, struct file *filp) | |
518 | { | |
519 | int decr, decw; | |
520 | ||
521 | pipe_rdwr_fasync(-1, filp, 0); | |
522 | decr = (filp->f_mode & FMODE_READ) != 0; | |
523 | decw = (filp->f_mode & FMODE_WRITE) != 0; | |
524 | return pipe_release(inode, decr, decw); | |
525 | } | |
526 | ||
527 | static int | |
528 | pipe_read_open(struct inode *inode, struct file *filp) | |
529 | { | |
530 | /* We could have perhaps used atomic_t, but this and friends | |
531 | below are the only places. So it doesn't seem worthwhile. */ | |
532 | down(PIPE_SEM(*inode)); | |
533 | PIPE_READERS(*inode)++; | |
534 | up(PIPE_SEM(*inode)); | |
535 | ||
536 | return 0; | |
537 | } | |
538 | ||
539 | static int | |
540 | pipe_write_open(struct inode *inode, struct file *filp) | |
541 | { | |
542 | down(PIPE_SEM(*inode)); | |
543 | PIPE_WRITERS(*inode)++; | |
544 | up(PIPE_SEM(*inode)); | |
545 | ||
546 | return 0; | |
547 | } | |
548 | ||
549 | static int | |
550 | pipe_rdwr_open(struct inode *inode, struct file *filp) | |
551 | { | |
552 | down(PIPE_SEM(*inode)); | |
553 | if (filp->f_mode & FMODE_READ) | |
554 | PIPE_READERS(*inode)++; | |
555 | if (filp->f_mode & FMODE_WRITE) | |
556 | PIPE_WRITERS(*inode)++; | |
557 | up(PIPE_SEM(*inode)); | |
558 | ||
559 | return 0; | |
560 | } | |
561 | ||
562 | /* | |
563 | * The file_operations structs are not static because they | |
564 | * are also used in linux/fs/fifo.c to do operations on FIFOs. | |
565 | */ | |
566 | struct file_operations read_fifo_fops = { | |
567 | .llseek = no_llseek, | |
568 | .read = pipe_read, | |
569 | .readv = pipe_readv, | |
570 | .write = bad_pipe_w, | |
571 | .poll = fifo_poll, | |
572 | .ioctl = pipe_ioctl, | |
573 | .open = pipe_read_open, | |
574 | .release = pipe_read_release, | |
575 | .fasync = pipe_read_fasync, | |
576 | }; | |
577 | ||
578 | struct file_operations write_fifo_fops = { | |
579 | .llseek = no_llseek, | |
580 | .read = bad_pipe_r, | |
581 | .write = pipe_write, | |
582 | .writev = pipe_writev, | |
583 | .poll = fifo_poll, | |
584 | .ioctl = pipe_ioctl, | |
585 | .open = pipe_write_open, | |
586 | .release = pipe_write_release, | |
587 | .fasync = pipe_write_fasync, | |
588 | }; | |
589 | ||
590 | struct file_operations rdwr_fifo_fops = { | |
591 | .llseek = no_llseek, | |
592 | .read = pipe_read, | |
593 | .readv = pipe_readv, | |
594 | .write = pipe_write, | |
595 | .writev = pipe_writev, | |
596 | .poll = fifo_poll, | |
597 | .ioctl = pipe_ioctl, | |
598 | .open = pipe_rdwr_open, | |
599 | .release = pipe_rdwr_release, | |
600 | .fasync = pipe_rdwr_fasync, | |
601 | }; | |
602 | ||
603 | struct file_operations read_pipe_fops = { | |
604 | .llseek = no_llseek, | |
605 | .read = pipe_read, | |
606 | .readv = pipe_readv, | |
607 | .write = bad_pipe_w, | |
608 | .poll = pipe_poll, | |
609 | .ioctl = pipe_ioctl, | |
610 | .open = pipe_read_open, | |
611 | .release = pipe_read_release, | |
612 | .fasync = pipe_read_fasync, | |
613 | }; | |
614 | ||
615 | struct file_operations write_pipe_fops = { | |
616 | .llseek = no_llseek, | |
617 | .read = bad_pipe_r, | |
618 | .write = pipe_write, | |
619 | .writev = pipe_writev, | |
620 | .poll = pipe_poll, | |
621 | .ioctl = pipe_ioctl, | |
622 | .open = pipe_write_open, | |
623 | .release = pipe_write_release, | |
624 | .fasync = pipe_write_fasync, | |
625 | }; | |
626 | ||
627 | struct file_operations rdwr_pipe_fops = { | |
628 | .llseek = no_llseek, | |
629 | .read = pipe_read, | |
630 | .readv = pipe_readv, | |
631 | .write = pipe_write, | |
632 | .writev = pipe_writev, | |
633 | .poll = pipe_poll, | |
634 | .ioctl = pipe_ioctl, | |
635 | .open = pipe_rdwr_open, | |
636 | .release = pipe_rdwr_release, | |
637 | .fasync = pipe_rdwr_fasync, | |
638 | }; | |
639 | ||
640 | void free_pipe_info(struct inode *inode) | |
641 | { | |
642 | int i; | |
643 | struct pipe_inode_info *info = inode->i_pipe; | |
644 | ||
645 | inode->i_pipe = NULL; | |
646 | for (i = 0; i < PIPE_BUFFERS; i++) { | |
647 | struct pipe_buffer *buf = info->bufs + i; | |
648 | if (buf->ops) | |
649 | buf->ops->release(info, buf); | |
650 | } | |
651 | if (info->tmp_page) | |
652 | __free_page(info->tmp_page); | |
653 | kfree(info); | |
654 | } | |
655 | ||
656 | struct inode* pipe_new(struct inode* inode) | |
657 | { | |
658 | struct pipe_inode_info *info; | |
659 | ||
660 | info = kmalloc(sizeof(struct pipe_inode_info), GFP_KERNEL); | |
661 | if (!info) | |
662 | goto fail_page; | |
663 | memset(info, 0, sizeof(*info)); | |
664 | inode->i_pipe = info; | |
665 | ||
666 | init_waitqueue_head(PIPE_WAIT(*inode)); | |
667 | PIPE_RCOUNTER(*inode) = PIPE_WCOUNTER(*inode) = 1; | |
668 | ||
669 | return inode; | |
670 | fail_page: | |
671 | return NULL; | |
672 | } | |
673 | ||
674 | static struct vfsmount *pipe_mnt; | |
675 | static int pipefs_delete_dentry(struct dentry *dentry) | |
676 | { | |
677 | return 1; | |
678 | } | |
679 | static struct dentry_operations pipefs_dentry_operations = { | |
680 | .d_delete = pipefs_delete_dentry, | |
681 | }; | |
682 | ||
683 | static struct inode * get_pipe_inode(void) | |
684 | { | |
685 | struct inode *inode = new_inode(pipe_mnt->mnt_sb); | |
686 | ||
687 | if (!inode) | |
688 | goto fail_inode; | |
689 | ||
690 | if(!pipe_new(inode)) | |
691 | goto fail_iput; | |
692 | PIPE_READERS(*inode) = PIPE_WRITERS(*inode) = 1; | |
693 | inode->i_fop = &rdwr_pipe_fops; | |
694 | ||
695 | /* | |
696 | * Mark the inode dirty from the very beginning, | |
697 | * that way it will never be moved to the dirty | |
698 | * list because "mark_inode_dirty()" will think | |
699 | * that it already _is_ on the dirty list. | |
700 | */ | |
701 | inode->i_state = I_DIRTY; | |
702 | inode->i_mode = S_IFIFO | S_IRUSR | S_IWUSR; | |
703 | inode->i_uid = current->fsuid; | |
704 | inode->i_gid = current->fsgid; | |
705 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; | |
706 | inode->i_blksize = PAGE_SIZE; | |
707 | return inode; | |
708 | ||
709 | fail_iput: | |
710 | iput(inode); | |
711 | fail_inode: | |
712 | return NULL; | |
713 | } | |
714 | ||
715 | int do_pipe(int *fd) | |
716 | { | |
717 | struct qstr this; | |
718 | char name[32]; | |
719 | struct dentry *dentry; | |
720 | struct inode * inode; | |
721 | struct file *f1, *f2; | |
722 | int error; | |
723 | int i,j; | |
724 | ||
725 | error = -ENFILE; | |
726 | f1 = get_empty_filp(); | |
727 | if (!f1) | |
728 | goto no_files; | |
729 | ||
730 | f2 = get_empty_filp(); | |
731 | if (!f2) | |
732 | goto close_f1; | |
733 | ||
734 | inode = get_pipe_inode(); | |
735 | if (!inode) | |
736 | goto close_f12; | |
737 | ||
738 | error = get_unused_fd(); | |
739 | if (error < 0) | |
740 | goto close_f12_inode; | |
741 | i = error; | |
742 | ||
743 | error = get_unused_fd(); | |
744 | if (error < 0) | |
745 | goto close_f12_inode_i; | |
746 | j = error; | |
747 | ||
748 | error = -ENOMEM; | |
749 | sprintf(name, "[%lu]", inode->i_ino); | |
750 | this.name = name; | |
751 | this.len = strlen(name); | |
752 | this.hash = inode->i_ino; /* will go */ | |
753 | dentry = d_alloc(pipe_mnt->mnt_sb->s_root, &this); | |
754 | if (!dentry) | |
755 | goto close_f12_inode_i_j; | |
756 | dentry->d_op = &pipefs_dentry_operations; | |
757 | d_add(dentry, inode); | |
758 | f1->f_vfsmnt = f2->f_vfsmnt = mntget(mntget(pipe_mnt)); | |
759 | f1->f_dentry = f2->f_dentry = dget(dentry); | |
760 | f1->f_mapping = f2->f_mapping = inode->i_mapping; | |
761 | ||
762 | /* read file */ | |
763 | f1->f_pos = f2->f_pos = 0; | |
764 | f1->f_flags = O_RDONLY; | |
765 | f1->f_op = &read_pipe_fops; | |
766 | f1->f_mode = FMODE_READ; | |
767 | f1->f_version = 0; | |
768 | ||
769 | /* write file */ | |
770 | f2->f_flags = O_WRONLY; | |
771 | f2->f_op = &write_pipe_fops; | |
772 | f2->f_mode = FMODE_WRITE; | |
773 | f2->f_version = 0; | |
774 | ||
775 | fd_install(i, f1); | |
776 | fd_install(j, f2); | |
777 | fd[0] = i; | |
778 | fd[1] = j; | |
779 | return 0; | |
780 | ||
781 | close_f12_inode_i_j: | |
782 | put_unused_fd(j); | |
783 | close_f12_inode_i: | |
784 | put_unused_fd(i); | |
785 | close_f12_inode: | |
786 | free_pipe_info(inode); | |
787 | iput(inode); | |
788 | close_f12: | |
789 | put_filp(f2); | |
790 | close_f1: | |
791 | put_filp(f1); | |
792 | no_files: | |
793 | return error; | |
794 | } | |
795 | ||
796 | /* | |
797 | * pipefs should _never_ be mounted by userland - too much of security hassle, | |
798 | * no real gain from having the whole whorehouse mounted. So we don't need | |
799 | * any operations on the root directory. However, we need a non-trivial | |
800 | * d_name - pipe: will go nicely and kill the special-casing in procfs. | |
801 | */ | |
802 | ||
803 | static struct super_block *pipefs_get_sb(struct file_system_type *fs_type, | |
804 | int flags, const char *dev_name, void *data) | |
805 | { | |
806 | return get_sb_pseudo(fs_type, "pipe:", NULL, PIPEFS_MAGIC); | |
807 | } | |
808 | ||
809 | static struct file_system_type pipe_fs_type = { | |
810 | .name = "pipefs", | |
811 | .get_sb = pipefs_get_sb, | |
812 | .kill_sb = kill_anon_super, | |
813 | }; | |
814 | ||
815 | static int __init init_pipe_fs(void) | |
816 | { | |
817 | int err = register_filesystem(&pipe_fs_type); | |
818 | if (!err) { | |
819 | pipe_mnt = kern_mount(&pipe_fs_type); | |
820 | if (IS_ERR(pipe_mnt)) { | |
821 | err = PTR_ERR(pipe_mnt); | |
822 | unregister_filesystem(&pipe_fs_type); | |
823 | } | |
824 | } | |
825 | return err; | |
826 | } | |
827 | ||
828 | static void __exit exit_pipe_fs(void) | |
829 | { | |
830 | unregister_filesystem(&pipe_fs_type); | |
831 | mntput(pipe_mnt); | |
832 | } | |
833 | ||
834 | fs_initcall(init_pipe_fs); | |
835 | module_exit(exit_pipe_fs); |