Contents of /alx-src/tags/kernel26-2.6.12-alx-r9/fs/pipe.c
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Wed Mar 4 11:03:09 2009 UTC (15 years, 6 months ago) by niro
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Wed Mar 4 11:03:09 2009 UTC (15 years, 6 months ago) by niro
File MIME type: text/plain
File size: 18682 byte(s)
Tag kernel26-2.6.12-alx-r9
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 | /* |
43 | * Pipes are system-local resources, so sleeping on them |
44 | * is considered a noninteractive wait: |
45 | */ |
46 | prepare_to_wait(PIPE_WAIT(*inode), &wait, TASK_INTERRUPTIBLE|TASK_NONINTERACTIVE); |
47 | up(PIPE_SEM(*inode)); |
48 | schedule(); |
49 | finish_wait(PIPE_WAIT(*inode), &wait); |
50 | down(PIPE_SEM(*inode)); |
51 | } |
52 | |
53 | static inline int |
54 | pipe_iov_copy_from_user(void *to, struct iovec *iov, unsigned long len) |
55 | { |
56 | unsigned long copy; |
57 | |
58 | while (len > 0) { |
59 | while (!iov->iov_len) |
60 | iov++; |
61 | copy = min_t(unsigned long, len, iov->iov_len); |
62 | |
63 | if (copy_from_user(to, iov->iov_base, copy)) |
64 | return -EFAULT; |
65 | to += copy; |
66 | len -= copy; |
67 | iov->iov_base += copy; |
68 | iov->iov_len -= copy; |
69 | } |
70 | return 0; |
71 | } |
72 | |
73 | static inline int |
74 | pipe_iov_copy_to_user(struct iovec *iov, const void *from, unsigned long len) |
75 | { |
76 | unsigned long copy; |
77 | |
78 | while (len > 0) { |
79 | while (!iov->iov_len) |
80 | iov++; |
81 | copy = min_t(unsigned long, len, iov->iov_len); |
82 | |
83 | if (copy_to_user(iov->iov_base, from, copy)) |
84 | return -EFAULT; |
85 | from += copy; |
86 | len -= copy; |
87 | iov->iov_base += copy; |
88 | iov->iov_len -= copy; |
89 | } |
90 | return 0; |
91 | } |
92 | |
93 | static void anon_pipe_buf_release(struct pipe_inode_info *info, struct pipe_buffer *buf) |
94 | { |
95 | struct page *page = buf->page; |
96 | |
97 | if (info->tmp_page) { |
98 | __free_page(page); |
99 | return; |
100 | } |
101 | info->tmp_page = page; |
102 | } |
103 | |
104 | static void *anon_pipe_buf_map(struct file *file, struct pipe_inode_info *info, struct pipe_buffer *buf) |
105 | { |
106 | return kmap(buf->page); |
107 | } |
108 | |
109 | static void anon_pipe_buf_unmap(struct pipe_inode_info *info, struct pipe_buffer *buf) |
110 | { |
111 | kunmap(buf->page); |
112 | } |
113 | |
114 | static struct pipe_buf_operations anon_pipe_buf_ops = { |
115 | .can_merge = 1, |
116 | .map = anon_pipe_buf_map, |
117 | .unmap = anon_pipe_buf_unmap, |
118 | .release = anon_pipe_buf_release, |
119 | }; |
120 | |
121 | static ssize_t |
122 | pipe_readv(struct file *filp, const struct iovec *_iov, |
123 | unsigned long nr_segs, loff_t *ppos) |
124 | { |
125 | struct inode *inode = filp->f_dentry->d_inode; |
126 | struct pipe_inode_info *info; |
127 | int do_wakeup; |
128 | ssize_t ret; |
129 | struct iovec *iov = (struct iovec *)_iov; |
130 | size_t total_len; |
131 | |
132 | total_len = iov_length(iov, nr_segs); |
133 | /* Null read succeeds. */ |
134 | if (unlikely(total_len == 0)) |
135 | return 0; |
136 | |
137 | do_wakeup = 0; |
138 | ret = 0; |
139 | down(PIPE_SEM(*inode)); |
140 | info = inode->i_pipe; |
141 | for (;;) { |
142 | int bufs = info->nrbufs; |
143 | if (bufs) { |
144 | int curbuf = info->curbuf; |
145 | struct pipe_buffer *buf = info->bufs + curbuf; |
146 | struct pipe_buf_operations *ops = buf->ops; |
147 | void *addr; |
148 | size_t chars = buf->len; |
149 | int error; |
150 | |
151 | if (chars > total_len) |
152 | chars = total_len; |
153 | |
154 | addr = ops->map(filp, info, buf); |
155 | error = pipe_iov_copy_to_user(iov, addr + buf->offset, chars); |
156 | ops->unmap(info, buf); |
157 | if (unlikely(error)) { |
158 | if (!ret) ret = -EFAULT; |
159 | break; |
160 | } |
161 | ret += chars; |
162 | buf->offset += chars; |
163 | buf->len -= chars; |
164 | if (!buf->len) { |
165 | buf->ops = NULL; |
166 | ops->release(info, buf); |
167 | curbuf = (curbuf + 1) & (PIPE_BUFFERS-1); |
168 | info->curbuf = curbuf; |
169 | info->nrbufs = --bufs; |
170 | do_wakeup = 1; |
171 | } |
172 | total_len -= chars; |
173 | if (!total_len) |
174 | break; /* common path: read succeeded */ |
175 | } |
176 | if (bufs) /* More to do? */ |
177 | continue; |
178 | if (!PIPE_WRITERS(*inode)) |
179 | break; |
180 | if (!PIPE_WAITING_WRITERS(*inode)) { |
181 | /* syscall merging: Usually we must not sleep |
182 | * if O_NONBLOCK is set, or if we got some data. |
183 | * But if a writer sleeps in kernel space, then |
184 | * we can wait for that data without violating POSIX. |
185 | */ |
186 | if (ret) |
187 | break; |
188 | if (filp->f_flags & O_NONBLOCK) { |
189 | ret = -EAGAIN; |
190 | break; |
191 | } |
192 | } |
193 | if (signal_pending(current)) { |
194 | if (!ret) ret = -ERESTARTSYS; |
195 | break; |
196 | } |
197 | if (do_wakeup) { |
198 | wake_up_interruptible_sync(PIPE_WAIT(*inode)); |
199 | kill_fasync(PIPE_FASYNC_WRITERS(*inode), SIGIO, POLL_OUT); |
200 | } |
201 | pipe_wait(inode); |
202 | } |
203 | up(PIPE_SEM(*inode)); |
204 | /* Signal writers asynchronously that there is more room. */ |
205 | if (do_wakeup) { |
206 | wake_up_interruptible(PIPE_WAIT(*inode)); |
207 | kill_fasync(PIPE_FASYNC_WRITERS(*inode), SIGIO, POLL_OUT); |
208 | } |
209 | if (ret > 0) |
210 | file_accessed(filp); |
211 | return ret; |
212 | } |
213 | |
214 | static ssize_t |
215 | pipe_read(struct file *filp, char __user *buf, size_t count, loff_t *ppos) |
216 | { |
217 | struct iovec iov = { .iov_base = buf, .iov_len = count }; |
218 | return pipe_readv(filp, &iov, 1, ppos); |
219 | } |
220 | |
221 | static ssize_t |
222 | pipe_writev(struct file *filp, const struct iovec *_iov, |
223 | unsigned long nr_segs, loff_t *ppos) |
224 | { |
225 | struct inode *inode = filp->f_dentry->d_inode; |
226 | struct pipe_inode_info *info; |
227 | ssize_t ret; |
228 | int do_wakeup; |
229 | struct iovec *iov = (struct iovec *)_iov; |
230 | size_t total_len; |
231 | ssize_t chars; |
232 | |
233 | total_len = iov_length(iov, nr_segs); |
234 | /* Null write succeeds. */ |
235 | if (unlikely(total_len == 0)) |
236 | return 0; |
237 | |
238 | do_wakeup = 0; |
239 | ret = 0; |
240 | down(PIPE_SEM(*inode)); |
241 | info = inode->i_pipe; |
242 | |
243 | if (!PIPE_READERS(*inode)) { |
244 | send_sig(SIGPIPE, current, 0); |
245 | ret = -EPIPE; |
246 | goto out; |
247 | } |
248 | |
249 | /* We try to merge small writes */ |
250 | chars = total_len & (PAGE_SIZE-1); /* size of the last buffer */ |
251 | if (info->nrbufs && chars != 0) { |
252 | int lastbuf = (info->curbuf + info->nrbufs - 1) & (PIPE_BUFFERS-1); |
253 | struct pipe_buffer *buf = info->bufs + lastbuf; |
254 | struct pipe_buf_operations *ops = buf->ops; |
255 | int offset = buf->offset + buf->len; |
256 | if (ops->can_merge && offset + chars <= PAGE_SIZE) { |
257 | void *addr = ops->map(filp, info, buf); |
258 | int error = pipe_iov_copy_from_user(offset + addr, iov, chars); |
259 | ops->unmap(info, buf); |
260 | ret = error; |
261 | do_wakeup = 1; |
262 | if (error) |
263 | goto out; |
264 | buf->len += chars; |
265 | total_len -= chars; |
266 | ret = chars; |
267 | if (!total_len) |
268 | goto out; |
269 | } |
270 | } |
271 | |
272 | for (;;) { |
273 | int bufs; |
274 | if (!PIPE_READERS(*inode)) { |
275 | send_sig(SIGPIPE, current, 0); |
276 | if (!ret) ret = -EPIPE; |
277 | break; |
278 | } |
279 | bufs = info->nrbufs; |
280 | if (bufs < PIPE_BUFFERS) { |
281 | int newbuf = (info->curbuf + bufs) & (PIPE_BUFFERS-1); |
282 | struct pipe_buffer *buf = info->bufs + newbuf; |
283 | struct page *page = info->tmp_page; |
284 | int error; |
285 | |
286 | if (!page) { |
287 | page = alloc_page(GFP_HIGHUSER); |
288 | if (unlikely(!page)) { |
289 | ret = ret ? : -ENOMEM; |
290 | break; |
291 | } |
292 | info->tmp_page = page; |
293 | } |
294 | /* Always wakeup, even if the copy fails. Otherwise |
295 | * we lock up (O_NONBLOCK-)readers that sleep due to |
296 | * syscall merging. |
297 | * FIXME! Is this really true? |
298 | */ |
299 | do_wakeup = 1; |
300 | chars = PAGE_SIZE; |
301 | if (chars > total_len) |
302 | chars = total_len; |
303 | |
304 | error = pipe_iov_copy_from_user(kmap(page), iov, chars); |
305 | kunmap(page); |
306 | if (unlikely(error)) { |
307 | if (!ret) ret = -EFAULT; |
308 | break; |
309 | } |
310 | ret += chars; |
311 | |
312 | /* Insert it into the buffer array */ |
313 | buf->page = page; |
314 | buf->ops = &anon_pipe_buf_ops; |
315 | buf->offset = 0; |
316 | buf->len = chars; |
317 | info->nrbufs = ++bufs; |
318 | info->tmp_page = NULL; |
319 | |
320 | total_len -= chars; |
321 | if (!total_len) |
322 | break; |
323 | } |
324 | if (bufs < PIPE_BUFFERS) |
325 | continue; |
326 | if (filp->f_flags & O_NONBLOCK) { |
327 | if (!ret) ret = -EAGAIN; |
328 | break; |
329 | } |
330 | if (signal_pending(current)) { |
331 | if (!ret) ret = -ERESTARTSYS; |
332 | break; |
333 | } |
334 | if (do_wakeup) { |
335 | wake_up_interruptible_sync(PIPE_WAIT(*inode)); |
336 | kill_fasync(PIPE_FASYNC_READERS(*inode), SIGIO, POLL_IN); |
337 | do_wakeup = 0; |
338 | } |
339 | PIPE_WAITING_WRITERS(*inode)++; |
340 | pipe_wait(inode); |
341 | PIPE_WAITING_WRITERS(*inode)--; |
342 | } |
343 | out: |
344 | up(PIPE_SEM(*inode)); |
345 | if (do_wakeup) { |
346 | wake_up_interruptible(PIPE_WAIT(*inode)); |
347 | kill_fasync(PIPE_FASYNC_READERS(*inode), SIGIO, POLL_IN); |
348 | } |
349 | if (ret > 0) |
350 | inode_update_time(inode, 1); /* mtime and ctime */ |
351 | return ret; |
352 | } |
353 | |
354 | static ssize_t |
355 | pipe_write(struct file *filp, const char __user *buf, |
356 | size_t count, loff_t *ppos) |
357 | { |
358 | struct iovec iov = { .iov_base = (void __user *)buf, .iov_len = count }; |
359 | return pipe_writev(filp, &iov, 1, ppos); |
360 | } |
361 | |
362 | static ssize_t |
363 | bad_pipe_r(struct file *filp, char __user *buf, size_t count, loff_t *ppos) |
364 | { |
365 | return -EBADF; |
366 | } |
367 | |
368 | static ssize_t |
369 | bad_pipe_w(struct file *filp, const char __user *buf, size_t count, loff_t *ppos) |
370 | { |
371 | return -EBADF; |
372 | } |
373 | |
374 | static int |
375 | pipe_ioctl(struct inode *pino, struct file *filp, |
376 | unsigned int cmd, unsigned long arg) |
377 | { |
378 | struct inode *inode = filp->f_dentry->d_inode; |
379 | struct pipe_inode_info *info; |
380 | int count, buf, nrbufs; |
381 | |
382 | switch (cmd) { |
383 | case FIONREAD: |
384 | down(PIPE_SEM(*inode)); |
385 | info = inode->i_pipe; |
386 | count = 0; |
387 | buf = info->curbuf; |
388 | nrbufs = info->nrbufs; |
389 | while (--nrbufs >= 0) { |
390 | count += info->bufs[buf].len; |
391 | buf = (buf+1) & (PIPE_BUFFERS-1); |
392 | } |
393 | up(PIPE_SEM(*inode)); |
394 | return put_user(count, (int __user *)arg); |
395 | default: |
396 | return -EINVAL; |
397 | } |
398 | } |
399 | |
400 | /* No kernel lock held - fine */ |
401 | static unsigned int |
402 | pipe_poll(struct file *filp, poll_table *wait) |
403 | { |
404 | unsigned int mask; |
405 | struct inode *inode = filp->f_dentry->d_inode; |
406 | struct pipe_inode_info *info = inode->i_pipe; |
407 | int nrbufs; |
408 | |
409 | poll_wait(filp, PIPE_WAIT(*inode), wait); |
410 | |
411 | /* Reading only -- no need for acquiring the semaphore. */ |
412 | nrbufs = info->nrbufs; |
413 | mask = 0; |
414 | if (filp->f_mode & FMODE_READ) { |
415 | mask = (nrbufs > 0) ? POLLIN | POLLRDNORM : 0; |
416 | if (!PIPE_WRITERS(*inode) && filp->f_version != PIPE_WCOUNTER(*inode)) |
417 | mask |= POLLHUP; |
418 | } |
419 | |
420 | if (filp->f_mode & FMODE_WRITE) { |
421 | mask |= (nrbufs < PIPE_BUFFERS) ? POLLOUT | POLLWRNORM : 0; |
422 | if (!PIPE_READERS(*inode)) |
423 | mask |= POLLERR; |
424 | } |
425 | |
426 | return mask; |
427 | } |
428 | |
429 | /* FIXME: most Unices do not set POLLERR for fifos */ |
430 | #define fifo_poll pipe_poll |
431 | |
432 | static int |
433 | pipe_release(struct inode *inode, int decr, int decw) |
434 | { |
435 | down(PIPE_SEM(*inode)); |
436 | PIPE_READERS(*inode) -= decr; |
437 | PIPE_WRITERS(*inode) -= decw; |
438 | if (!PIPE_READERS(*inode) && !PIPE_WRITERS(*inode)) { |
439 | free_pipe_info(inode); |
440 | } else { |
441 | wake_up_interruptible(PIPE_WAIT(*inode)); |
442 | kill_fasync(PIPE_FASYNC_READERS(*inode), SIGIO, POLL_IN); |
443 | kill_fasync(PIPE_FASYNC_WRITERS(*inode), SIGIO, POLL_OUT); |
444 | } |
445 | up(PIPE_SEM(*inode)); |
446 | |
447 | return 0; |
448 | } |
449 | |
450 | static int |
451 | pipe_read_fasync(int fd, struct file *filp, int on) |
452 | { |
453 | struct inode *inode = filp->f_dentry->d_inode; |
454 | int retval; |
455 | |
456 | down(PIPE_SEM(*inode)); |
457 | retval = fasync_helper(fd, filp, on, PIPE_FASYNC_READERS(*inode)); |
458 | up(PIPE_SEM(*inode)); |
459 | |
460 | if (retval < 0) |
461 | return retval; |
462 | |
463 | return 0; |
464 | } |
465 | |
466 | |
467 | static int |
468 | pipe_write_fasync(int fd, struct file *filp, int on) |
469 | { |
470 | struct inode *inode = filp->f_dentry->d_inode; |
471 | int retval; |
472 | |
473 | down(PIPE_SEM(*inode)); |
474 | retval = fasync_helper(fd, filp, on, PIPE_FASYNC_WRITERS(*inode)); |
475 | up(PIPE_SEM(*inode)); |
476 | |
477 | if (retval < 0) |
478 | return retval; |
479 | |
480 | return 0; |
481 | } |
482 | |
483 | |
484 | static int |
485 | pipe_rdwr_fasync(int fd, struct file *filp, int on) |
486 | { |
487 | struct inode *inode = filp->f_dentry->d_inode; |
488 | int retval; |
489 | |
490 | down(PIPE_SEM(*inode)); |
491 | |
492 | retval = fasync_helper(fd, filp, on, PIPE_FASYNC_READERS(*inode)); |
493 | |
494 | if (retval >= 0) |
495 | retval = fasync_helper(fd, filp, on, PIPE_FASYNC_WRITERS(*inode)); |
496 | |
497 | up(PIPE_SEM(*inode)); |
498 | |
499 | if (retval < 0) |
500 | return retval; |
501 | |
502 | return 0; |
503 | } |
504 | |
505 | |
506 | static int |
507 | pipe_read_release(struct inode *inode, struct file *filp) |
508 | { |
509 | pipe_read_fasync(-1, filp, 0); |
510 | return pipe_release(inode, 1, 0); |
511 | } |
512 | |
513 | static int |
514 | pipe_write_release(struct inode *inode, struct file *filp) |
515 | { |
516 | pipe_write_fasync(-1, filp, 0); |
517 | return pipe_release(inode, 0, 1); |
518 | } |
519 | |
520 | static int |
521 | pipe_rdwr_release(struct inode *inode, struct file *filp) |
522 | { |
523 | int decr, decw; |
524 | |
525 | pipe_rdwr_fasync(-1, filp, 0); |
526 | decr = (filp->f_mode & FMODE_READ) != 0; |
527 | decw = (filp->f_mode & FMODE_WRITE) != 0; |
528 | return pipe_release(inode, decr, decw); |
529 | } |
530 | |
531 | static int |
532 | pipe_read_open(struct inode *inode, struct file *filp) |
533 | { |
534 | /* We could have perhaps used atomic_t, but this and friends |
535 | below are the only places. So it doesn't seem worthwhile. */ |
536 | down(PIPE_SEM(*inode)); |
537 | PIPE_READERS(*inode)++; |
538 | up(PIPE_SEM(*inode)); |
539 | |
540 | return 0; |
541 | } |
542 | |
543 | static int |
544 | pipe_write_open(struct inode *inode, struct file *filp) |
545 | { |
546 | down(PIPE_SEM(*inode)); |
547 | PIPE_WRITERS(*inode)++; |
548 | up(PIPE_SEM(*inode)); |
549 | |
550 | return 0; |
551 | } |
552 | |
553 | static int |
554 | pipe_rdwr_open(struct inode *inode, struct file *filp) |
555 | { |
556 | down(PIPE_SEM(*inode)); |
557 | if (filp->f_mode & FMODE_READ) |
558 | PIPE_READERS(*inode)++; |
559 | if (filp->f_mode & FMODE_WRITE) |
560 | PIPE_WRITERS(*inode)++; |
561 | up(PIPE_SEM(*inode)); |
562 | |
563 | return 0; |
564 | } |
565 | |
566 | /* |
567 | * The file_operations structs are not static because they |
568 | * are also used in linux/fs/fifo.c to do operations on FIFOs. |
569 | */ |
570 | struct file_operations read_fifo_fops = { |
571 | .llseek = no_llseek, |
572 | .read = pipe_read, |
573 | .readv = pipe_readv, |
574 | .write = bad_pipe_w, |
575 | .poll = fifo_poll, |
576 | .ioctl = pipe_ioctl, |
577 | .open = pipe_read_open, |
578 | .release = pipe_read_release, |
579 | .fasync = pipe_read_fasync, |
580 | }; |
581 | |
582 | struct file_operations write_fifo_fops = { |
583 | .llseek = no_llseek, |
584 | .read = bad_pipe_r, |
585 | .write = pipe_write, |
586 | .writev = pipe_writev, |
587 | .poll = fifo_poll, |
588 | .ioctl = pipe_ioctl, |
589 | .open = pipe_write_open, |
590 | .release = pipe_write_release, |
591 | .fasync = pipe_write_fasync, |
592 | }; |
593 | |
594 | struct file_operations rdwr_fifo_fops = { |
595 | .llseek = no_llseek, |
596 | .read = pipe_read, |
597 | .readv = pipe_readv, |
598 | .write = pipe_write, |
599 | .writev = pipe_writev, |
600 | .poll = fifo_poll, |
601 | .ioctl = pipe_ioctl, |
602 | .open = pipe_rdwr_open, |
603 | .release = pipe_rdwr_release, |
604 | .fasync = pipe_rdwr_fasync, |
605 | }; |
606 | |
607 | struct file_operations read_pipe_fops = { |
608 | .llseek = no_llseek, |
609 | .read = pipe_read, |
610 | .readv = pipe_readv, |
611 | .write = bad_pipe_w, |
612 | .poll = pipe_poll, |
613 | .ioctl = pipe_ioctl, |
614 | .open = pipe_read_open, |
615 | .release = pipe_read_release, |
616 | .fasync = pipe_read_fasync, |
617 | }; |
618 | |
619 | struct file_operations write_pipe_fops = { |
620 | .llseek = no_llseek, |
621 | .read = bad_pipe_r, |
622 | .write = pipe_write, |
623 | .writev = pipe_writev, |
624 | .poll = pipe_poll, |
625 | .ioctl = pipe_ioctl, |
626 | .open = pipe_write_open, |
627 | .release = pipe_write_release, |
628 | .fasync = pipe_write_fasync, |
629 | }; |
630 | |
631 | struct file_operations rdwr_pipe_fops = { |
632 | .llseek = no_llseek, |
633 | .read = pipe_read, |
634 | .readv = pipe_readv, |
635 | .write = pipe_write, |
636 | .writev = pipe_writev, |
637 | .poll = pipe_poll, |
638 | .ioctl = pipe_ioctl, |
639 | .open = pipe_rdwr_open, |
640 | .release = pipe_rdwr_release, |
641 | .fasync = pipe_rdwr_fasync, |
642 | }; |
643 | |
644 | void free_pipe_info(struct inode *inode) |
645 | { |
646 | int i; |
647 | struct pipe_inode_info *info = inode->i_pipe; |
648 | |
649 | inode->i_pipe = NULL; |
650 | for (i = 0; i < PIPE_BUFFERS; i++) { |
651 | struct pipe_buffer *buf = info->bufs + i; |
652 | if (buf->ops) |
653 | buf->ops->release(info, buf); |
654 | } |
655 | if (info->tmp_page) |
656 | __free_page(info->tmp_page); |
657 | kfree(info); |
658 | } |
659 | |
660 | struct inode* pipe_new(struct inode* inode) |
661 | { |
662 | struct pipe_inode_info *info; |
663 | |
664 | info = kmalloc(sizeof(struct pipe_inode_info), GFP_KERNEL); |
665 | if (!info) |
666 | goto fail_page; |
667 | memset(info, 0, sizeof(*info)); |
668 | inode->i_pipe = info; |
669 | |
670 | init_waitqueue_head(PIPE_WAIT(*inode)); |
671 | PIPE_RCOUNTER(*inode) = PIPE_WCOUNTER(*inode) = 1; |
672 | |
673 | return inode; |
674 | fail_page: |
675 | return NULL; |
676 | } |
677 | |
678 | static struct vfsmount *pipe_mnt; |
679 | static int pipefs_delete_dentry(struct dentry *dentry) |
680 | { |
681 | return 1; |
682 | } |
683 | static struct dentry_operations pipefs_dentry_operations = { |
684 | .d_delete = pipefs_delete_dentry, |
685 | }; |
686 | |
687 | static struct inode * get_pipe_inode(void) |
688 | { |
689 | struct inode *inode = new_inode(pipe_mnt->mnt_sb); |
690 | |
691 | if (!inode) |
692 | goto fail_inode; |
693 | |
694 | if(!pipe_new(inode)) |
695 | goto fail_iput; |
696 | PIPE_READERS(*inode) = PIPE_WRITERS(*inode) = 1; |
697 | inode->i_fop = &rdwr_pipe_fops; |
698 | |
699 | /* |
700 | * Mark the inode dirty from the very beginning, |
701 | * that way it will never be moved to the dirty |
702 | * list because "mark_inode_dirty()" will think |
703 | * that it already _is_ on the dirty list. |
704 | */ |
705 | inode->i_state = I_DIRTY; |
706 | inode->i_mode = S_IFIFO | S_IRUSR | S_IWUSR; |
707 | inode->i_uid = current->fsuid; |
708 | inode->i_gid = current->fsgid; |
709 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; |
710 | inode->i_blksize = PAGE_SIZE; |
711 | return inode; |
712 | |
713 | fail_iput: |
714 | iput(inode); |
715 | fail_inode: |
716 | return NULL; |
717 | } |
718 | |
719 | int do_pipe(int *fd) |
720 | { |
721 | struct qstr this; |
722 | char name[32]; |
723 | struct dentry *dentry; |
724 | struct inode * inode; |
725 | struct file *f1, *f2; |
726 | int error; |
727 | int i,j; |
728 | |
729 | error = -ENFILE; |
730 | f1 = get_empty_filp(); |
731 | if (!f1) |
732 | goto no_files; |
733 | |
734 | f2 = get_empty_filp(); |
735 | if (!f2) |
736 | goto close_f1; |
737 | |
738 | inode = get_pipe_inode(); |
739 | if (!inode) |
740 | goto close_f12; |
741 | |
742 | error = get_unused_fd(); |
743 | if (error < 0) |
744 | goto close_f12_inode; |
745 | i = error; |
746 | |
747 | error = get_unused_fd(); |
748 | if (error < 0) |
749 | goto close_f12_inode_i; |
750 | j = error; |
751 | |
752 | error = -ENOMEM; |
753 | sprintf(name, "[%lu]", inode->i_ino); |
754 | this.name = name; |
755 | this.len = strlen(name); |
756 | this.hash = inode->i_ino; /* will go */ |
757 | dentry = d_alloc(pipe_mnt->mnt_sb->s_root, &this); |
758 | if (!dentry) |
759 | goto close_f12_inode_i_j; |
760 | dentry->d_op = &pipefs_dentry_operations; |
761 | d_add(dentry, inode); |
762 | f1->f_vfsmnt = f2->f_vfsmnt = mntget(mntget(pipe_mnt)); |
763 | f1->f_dentry = f2->f_dentry = dget(dentry); |
764 | f1->f_mapping = f2->f_mapping = inode->i_mapping; |
765 | |
766 | /* read file */ |
767 | f1->f_pos = f2->f_pos = 0; |
768 | f1->f_flags = O_RDONLY; |
769 | f1->f_op = &read_pipe_fops; |
770 | f1->f_mode = FMODE_READ; |
771 | f1->f_version = 0; |
772 | |
773 | /* write file */ |
774 | f2->f_flags = O_WRONLY; |
775 | f2->f_op = &write_pipe_fops; |
776 | f2->f_mode = FMODE_WRITE; |
777 | f2->f_version = 0; |
778 | |
779 | fd_install(i, f1); |
780 | fd_install(j, f2); |
781 | fd[0] = i; |
782 | fd[1] = j; |
783 | return 0; |
784 | |
785 | close_f12_inode_i_j: |
786 | put_unused_fd(j); |
787 | close_f12_inode_i: |
788 | put_unused_fd(i); |
789 | close_f12_inode: |
790 | free_pipe_info(inode); |
791 | iput(inode); |
792 | close_f12: |
793 | put_filp(f2); |
794 | close_f1: |
795 | put_filp(f1); |
796 | no_files: |
797 | return error; |
798 | } |
799 | |
800 | /* |
801 | * pipefs should _never_ be mounted by userland - too much of security hassle, |
802 | * no real gain from having the whole whorehouse mounted. So we don't need |
803 | * any operations on the root directory. However, we need a non-trivial |
804 | * d_name - pipe: will go nicely and kill the special-casing in procfs. |
805 | */ |
806 | |
807 | static struct super_block *pipefs_get_sb(struct file_system_type *fs_type, |
808 | int flags, const char *dev_name, void *data) |
809 | { |
810 | return get_sb_pseudo(fs_type, "pipe:", NULL, PIPEFS_MAGIC); |
811 | } |
812 | |
813 | static struct file_system_type pipe_fs_type = { |
814 | .name = "pipefs", |
815 | .get_sb = pipefs_get_sb, |
816 | .kill_sb = kill_anon_super, |
817 | }; |
818 | |
819 | static int __init init_pipe_fs(void) |
820 | { |
821 | int err = register_filesystem(&pipe_fs_type); |
822 | if (!err) { |
823 | pipe_mnt = kern_mount(&pipe_fs_type); |
824 | if (IS_ERR(pipe_mnt)) { |
825 | err = PTR_ERR(pipe_mnt); |
826 | unregister_filesystem(&pipe_fs_type); |
827 | } |
828 | } |
829 | return err; |
830 | } |
831 | |
832 | static void __exit exit_pipe_fs(void) |
833 | { |
834 | unregister_filesystem(&pipe_fs_type); |
835 | mntput(pipe_mnt); |
836 | } |
837 | |
838 | fs_initcall(init_pipe_fs); |
839 | module_exit(exit_pipe_fs); |