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1 | /* |
2 | * linux/fs/fcntl.c |
3 | * |
4 | * Copyright (C) 1991, 1992 Linus Torvalds |
5 | */ |
6 | |
7 | #include <linux/syscalls.h> |
8 | #include <linux/init.h> |
9 | #include <linux/mm.h> |
10 | #include <linux/fs.h> |
11 | #include <linux/file.h> |
12 | #include <linux/fdtable.h> |
13 | #include <linux/capability.h> |
14 | #include <linux/dnotify.h> |
15 | #include <linux/slab.h> |
16 | #include <linux/module.h> |
17 | #include <linux/pipe_fs_i.h> |
18 | #include <linux/security.h> |
19 | #include <linux/ptrace.h> |
20 | #include <linux/signal.h> |
21 | #include <linux/rcupdate.h> |
22 | #include <linux/pid_namespace.h> |
23 | #include <linux/user_namespace.h> |
24 | |
25 | #include <asm/poll.h> |
26 | #include <asm/siginfo.h> |
27 | #include <asm/uaccess.h> |
28 | |
29 | #define SETFL_MASK (O_APPEND | O_NONBLOCK | O_NDELAY | O_DIRECT | O_NOATIME) |
30 | |
31 | static int setfl(int fd, struct file * filp, unsigned long arg) |
32 | { |
33 | struct inode * inode = file_inode(filp); |
34 | int error = 0; |
35 | |
36 | /* |
37 | * O_APPEND cannot be cleared if the file is marked as append-only |
38 | * and the file is open for write. |
39 | */ |
40 | if (((arg ^ filp->f_flags) & O_APPEND) && IS_APPEND(inode)) |
41 | return -EPERM; |
42 | |
43 | /* O_NOATIME can only be set by the owner or superuser */ |
44 | if ((arg & O_NOATIME) && !(filp->f_flags & O_NOATIME)) |
45 | if (!inode_owner_or_capable(inode)) |
46 | return -EPERM; |
47 | |
48 | /* required for strict SunOS emulation */ |
49 | if (O_NONBLOCK != O_NDELAY) |
50 | if (arg & O_NDELAY) |
51 | arg |= O_NONBLOCK; |
52 | |
53 | if (arg & O_DIRECT) { |
54 | if (!filp->f_mapping || !filp->f_mapping->a_ops || |
55 | !filp->f_mapping->a_ops->direct_IO) |
56 | return -EINVAL; |
57 | } |
58 | |
59 | if (filp->f_op->check_flags) |
60 | error = filp->f_op->check_flags(arg); |
61 | if (error) |
62 | return error; |
63 | |
64 | /* |
65 | * ->fasync() is responsible for setting the FASYNC bit. |
66 | */ |
67 | if (((arg ^ filp->f_flags) & FASYNC) && filp->f_op->fasync) { |
68 | error = filp->f_op->fasync(fd, filp, (arg & FASYNC) != 0); |
69 | if (error < 0) |
70 | goto out; |
71 | if (error > 0) |
72 | error = 0; |
73 | } |
74 | spin_lock(&filp->f_lock); |
75 | filp->f_flags = (arg & SETFL_MASK) | (filp->f_flags & ~SETFL_MASK); |
76 | spin_unlock(&filp->f_lock); |
77 | |
78 | out: |
79 | return error; |
80 | } |
81 | |
82 | static void f_modown(struct file *filp, struct pid *pid, enum pid_type type, |
83 | int force) |
84 | { |
85 | write_lock_irq(&filp->f_owner.lock); |
86 | if (force || !filp->f_owner.pid) { |
87 | put_pid(filp->f_owner.pid); |
88 | filp->f_owner.pid = get_pid(pid); |
89 | filp->f_owner.pid_type = type; |
90 | |
91 | if (pid) { |
92 | const struct cred *cred = current_cred(); |
93 | filp->f_owner.uid = cred->uid; |
94 | filp->f_owner.euid = cred->euid; |
95 | } |
96 | } |
97 | write_unlock_irq(&filp->f_owner.lock); |
98 | } |
99 | |
100 | int __f_setown(struct file *filp, struct pid *pid, enum pid_type type, |
101 | int force) |
102 | { |
103 | int err; |
104 | |
105 | err = security_file_set_fowner(filp); |
106 | if (err) |
107 | return err; |
108 | |
109 | f_modown(filp, pid, type, force); |
110 | return 0; |
111 | } |
112 | EXPORT_SYMBOL(__f_setown); |
113 | |
114 | int f_setown(struct file *filp, unsigned long arg, int force) |
115 | { |
116 | enum pid_type type; |
117 | struct pid *pid; |
118 | int who = arg; |
119 | int result; |
120 | type = PIDTYPE_PID; |
121 | if (who < 0) { |
122 | type = PIDTYPE_PGID; |
123 | who = -who; |
124 | } |
125 | rcu_read_lock(); |
126 | pid = find_vpid(who); |
127 | result = __f_setown(filp, pid, type, force); |
128 | rcu_read_unlock(); |
129 | return result; |
130 | } |
131 | EXPORT_SYMBOL(f_setown); |
132 | |
133 | void f_delown(struct file *filp) |
134 | { |
135 | f_modown(filp, NULL, PIDTYPE_PID, 1); |
136 | } |
137 | |
138 | pid_t f_getown(struct file *filp) |
139 | { |
140 | pid_t pid; |
141 | read_lock(&filp->f_owner.lock); |
142 | pid = pid_vnr(filp->f_owner.pid); |
143 | if (filp->f_owner.pid_type == PIDTYPE_PGID) |
144 | pid = -pid; |
145 | read_unlock(&filp->f_owner.lock); |
146 | return pid; |
147 | } |
148 | |
149 | static int f_setown_ex(struct file *filp, unsigned long arg) |
150 | { |
151 | struct f_owner_ex __user *owner_p = (void __user *)arg; |
152 | struct f_owner_ex owner; |
153 | struct pid *pid; |
154 | int type; |
155 | int ret; |
156 | |
157 | ret = copy_from_user(&owner, owner_p, sizeof(owner)); |
158 | if (ret) |
159 | return -EFAULT; |
160 | |
161 | switch (owner.type) { |
162 | case F_OWNER_TID: |
163 | type = PIDTYPE_MAX; |
164 | break; |
165 | |
166 | case F_OWNER_PID: |
167 | type = PIDTYPE_PID; |
168 | break; |
169 | |
170 | case F_OWNER_PGRP: |
171 | type = PIDTYPE_PGID; |
172 | break; |
173 | |
174 | default: |
175 | return -EINVAL; |
176 | } |
177 | |
178 | rcu_read_lock(); |
179 | pid = find_vpid(owner.pid); |
180 | if (owner.pid && !pid) |
181 | ret = -ESRCH; |
182 | else |
183 | ret = __f_setown(filp, pid, type, 1); |
184 | rcu_read_unlock(); |
185 | |
186 | return ret; |
187 | } |
188 | |
189 | static int f_getown_ex(struct file *filp, unsigned long arg) |
190 | { |
191 | struct f_owner_ex __user *owner_p = (void __user *)arg; |
192 | struct f_owner_ex owner; |
193 | int ret = 0; |
194 | |
195 | read_lock(&filp->f_owner.lock); |
196 | owner.pid = pid_vnr(filp->f_owner.pid); |
197 | switch (filp->f_owner.pid_type) { |
198 | case PIDTYPE_MAX: |
199 | owner.type = F_OWNER_TID; |
200 | break; |
201 | |
202 | case PIDTYPE_PID: |
203 | owner.type = F_OWNER_PID; |
204 | break; |
205 | |
206 | case PIDTYPE_PGID: |
207 | owner.type = F_OWNER_PGRP; |
208 | break; |
209 | |
210 | default: |
211 | WARN_ON(1); |
212 | ret = -EINVAL; |
213 | break; |
214 | } |
215 | read_unlock(&filp->f_owner.lock); |
216 | |
217 | if (!ret) { |
218 | ret = copy_to_user(owner_p, &owner, sizeof(owner)); |
219 | if (ret) |
220 | ret = -EFAULT; |
221 | } |
222 | return ret; |
223 | } |
224 | |
225 | #ifdef CONFIG_CHECKPOINT_RESTORE |
226 | static int f_getowner_uids(struct file *filp, unsigned long arg) |
227 | { |
228 | struct user_namespace *user_ns = current_user_ns(); |
229 | uid_t __user *dst = (void __user *)arg; |
230 | uid_t src[2]; |
231 | int err; |
232 | |
233 | read_lock(&filp->f_owner.lock); |
234 | src[0] = from_kuid(user_ns, filp->f_owner.uid); |
235 | src[1] = from_kuid(user_ns, filp->f_owner.euid); |
236 | read_unlock(&filp->f_owner.lock); |
237 | |
238 | err = put_user(src[0], &dst[0]); |
239 | err |= put_user(src[1], &dst[1]); |
240 | |
241 | return err; |
242 | } |
243 | #else |
244 | static int f_getowner_uids(struct file *filp, unsigned long arg) |
245 | { |
246 | return -EINVAL; |
247 | } |
248 | #endif |
249 | |
250 | static long do_fcntl(int fd, unsigned int cmd, unsigned long arg, |
251 | struct file *filp) |
252 | { |
253 | long err = -EINVAL; |
254 | |
255 | switch (cmd) { |
256 | case F_DUPFD: |
257 | err = f_dupfd(arg, filp, 0); |
258 | break; |
259 | case F_DUPFD_CLOEXEC: |
260 | err = f_dupfd(arg, filp, O_CLOEXEC); |
261 | break; |
262 | case F_GETFD: |
263 | err = get_close_on_exec(fd) ? FD_CLOEXEC : 0; |
264 | break; |
265 | case F_SETFD: |
266 | err = 0; |
267 | set_close_on_exec(fd, arg & FD_CLOEXEC); |
268 | break; |
269 | case F_GETFL: |
270 | err = filp->f_flags; |
271 | break; |
272 | case F_SETFL: |
273 | err = setfl(fd, filp, arg); |
274 | break; |
275 | #if BITS_PER_LONG != 32 |
276 | /* 32-bit arches must use fcntl64() */ |
277 | case F_OFD_GETLK: |
278 | #endif |
279 | case F_GETLK: |
280 | err = fcntl_getlk(filp, cmd, (struct flock __user *) arg); |
281 | break; |
282 | #if BITS_PER_LONG != 32 |
283 | /* 32-bit arches must use fcntl64() */ |
284 | case F_OFD_SETLK: |
285 | case F_OFD_SETLKW: |
286 | #endif |
287 | /* Fallthrough */ |
288 | case F_SETLK: |
289 | case F_SETLKW: |
290 | err = fcntl_setlk(fd, filp, cmd, (struct flock __user *) arg); |
291 | break; |
292 | case F_GETOWN: |
293 | /* |
294 | * XXX If f_owner is a process group, the |
295 | * negative return value will get converted |
296 | * into an error. Oops. If we keep the |
297 | * current syscall conventions, the only way |
298 | * to fix this will be in libc. |
299 | */ |
300 | err = f_getown(filp); |
301 | force_successful_syscall_return(); |
302 | break; |
303 | case F_SETOWN: |
304 | err = f_setown(filp, arg, 1); |
305 | break; |
306 | case F_GETOWN_EX: |
307 | err = f_getown_ex(filp, arg); |
308 | break; |
309 | case F_SETOWN_EX: |
310 | err = f_setown_ex(filp, arg); |
311 | break; |
312 | case F_GETOWNER_UIDS: |
313 | err = f_getowner_uids(filp, arg); |
314 | break; |
315 | case F_GETSIG: |
316 | err = filp->f_owner.signum; |
317 | break; |
318 | case F_SETSIG: |
319 | /* arg == 0 restores default behaviour. */ |
320 | if (!valid_signal(arg)) { |
321 | break; |
322 | } |
323 | err = 0; |
324 | filp->f_owner.signum = arg; |
325 | break; |
326 | case F_GETLEASE: |
327 | err = fcntl_getlease(filp); |
328 | break; |
329 | case F_SETLEASE: |
330 | err = fcntl_setlease(fd, filp, arg); |
331 | break; |
332 | case F_NOTIFY: |
333 | err = fcntl_dirnotify(fd, filp, arg); |
334 | break; |
335 | case F_SETPIPE_SZ: |
336 | case F_GETPIPE_SZ: |
337 | err = pipe_fcntl(filp, cmd, arg); |
338 | break; |
339 | default: |
340 | break; |
341 | } |
342 | return err; |
343 | } |
344 | |
345 | static int check_fcntl_cmd(unsigned cmd) |
346 | { |
347 | switch (cmd) { |
348 | case F_DUPFD: |
349 | case F_DUPFD_CLOEXEC: |
350 | case F_GETFD: |
351 | case F_SETFD: |
352 | case F_GETFL: |
353 | return 1; |
354 | } |
355 | return 0; |
356 | } |
357 | |
358 | SYSCALL_DEFINE3(fcntl, unsigned int, fd, unsigned int, cmd, unsigned long, arg) |
359 | { |
360 | struct fd f = fdget_raw(fd); |
361 | long err = -EBADF; |
362 | |
363 | if (!f.file) |
364 | goto out; |
365 | |
366 | if (unlikely(f.file->f_mode & FMODE_PATH)) { |
367 | if (!check_fcntl_cmd(cmd)) |
368 | goto out1; |
369 | } |
370 | |
371 | err = security_file_fcntl(f.file, cmd, arg); |
372 | if (!err) |
373 | err = do_fcntl(fd, cmd, arg, f.file); |
374 | |
375 | out1: |
376 | fdput(f); |
377 | out: |
378 | return err; |
379 | } |
380 | |
381 | #if BITS_PER_LONG == 32 |
382 | SYSCALL_DEFINE3(fcntl64, unsigned int, fd, unsigned int, cmd, |
383 | unsigned long, arg) |
384 | { |
385 | struct fd f = fdget_raw(fd); |
386 | long err = -EBADF; |
387 | |
388 | if (!f.file) |
389 | goto out; |
390 | |
391 | if (unlikely(f.file->f_mode & FMODE_PATH)) { |
392 | if (!check_fcntl_cmd(cmd)) |
393 | goto out1; |
394 | } |
395 | |
396 | err = security_file_fcntl(f.file, cmd, arg); |
397 | if (err) |
398 | goto out1; |
399 | |
400 | switch (cmd) { |
401 | case F_GETLK64: |
402 | case F_OFD_GETLK: |
403 | err = fcntl_getlk64(f.file, cmd, (struct flock64 __user *) arg); |
404 | break; |
405 | case F_SETLK64: |
406 | case F_SETLKW64: |
407 | case F_OFD_SETLK: |
408 | case F_OFD_SETLKW: |
409 | err = fcntl_setlk64(fd, f.file, cmd, |
410 | (struct flock64 __user *) arg); |
411 | break; |
412 | default: |
413 | err = do_fcntl(fd, cmd, arg, f.file); |
414 | break; |
415 | } |
416 | out1: |
417 | fdput(f); |
418 | out: |
419 | return err; |
420 | } |
421 | #endif |
422 | |
423 | /* Table to convert sigio signal codes into poll band bitmaps */ |
424 | |
425 | static const long band_table[NSIGPOLL] = { |
426 | POLLIN | POLLRDNORM, /* POLL_IN */ |
427 | POLLOUT | POLLWRNORM | POLLWRBAND, /* POLL_OUT */ |
428 | POLLIN | POLLRDNORM | POLLMSG, /* POLL_MSG */ |
429 | POLLERR, /* POLL_ERR */ |
430 | POLLPRI | POLLRDBAND, /* POLL_PRI */ |
431 | POLLHUP | POLLERR /* POLL_HUP */ |
432 | }; |
433 | |
434 | static inline int sigio_perm(struct task_struct *p, |
435 | struct fown_struct *fown, int sig) |
436 | { |
437 | const struct cred *cred; |
438 | int ret; |
439 | |
440 | rcu_read_lock(); |
441 | cred = __task_cred(p); |
442 | ret = ((uid_eq(fown->euid, GLOBAL_ROOT_UID) || |
443 | uid_eq(fown->euid, cred->suid) || uid_eq(fown->euid, cred->uid) || |
444 | uid_eq(fown->uid, cred->suid) || uid_eq(fown->uid, cred->uid)) && |
445 | !security_file_send_sigiotask(p, fown, sig)); |
446 | rcu_read_unlock(); |
447 | return ret; |
448 | } |
449 | |
450 | static void send_sigio_to_task(struct task_struct *p, |
451 | struct fown_struct *fown, |
452 | int fd, int reason, int group) |
453 | { |
454 | /* |
455 | * F_SETSIG can change ->signum lockless in parallel, make |
456 | * sure we read it once and use the same value throughout. |
457 | */ |
458 | int signum = ACCESS_ONCE(fown->signum); |
459 | |
460 | if (!sigio_perm(p, fown, signum)) |
461 | return; |
462 | |
463 | switch (signum) { |
464 | siginfo_t si; |
465 | default: |
466 | /* Queue a rt signal with the appropriate fd as its |
467 | value. We use SI_SIGIO as the source, not |
468 | SI_KERNEL, since kernel signals always get |
469 | delivered even if we can't queue. Failure to |
470 | queue in this case _should_ be reported; we fall |
471 | back to SIGIO in that case. --sct */ |
472 | si.si_signo = signum; |
473 | si.si_errno = 0; |
474 | si.si_code = reason; |
475 | /* Make sure we are called with one of the POLL_* |
476 | reasons, otherwise we could leak kernel stack into |
477 | userspace. */ |
478 | BUG_ON((reason & __SI_MASK) != __SI_POLL); |
479 | if (reason - POLL_IN >= NSIGPOLL) |
480 | si.si_band = ~0L; |
481 | else |
482 | si.si_band = band_table[reason - POLL_IN]; |
483 | si.si_fd = fd; |
484 | if (!do_send_sig_info(signum, &si, p, group)) |
485 | break; |
486 | /* fall-through: fall back on the old plain SIGIO signal */ |
487 | case 0: |
488 | do_send_sig_info(SIGIO, SEND_SIG_PRIV, p, group); |
489 | } |
490 | } |
491 | |
492 | void send_sigio(struct fown_struct *fown, int fd, int band) |
493 | { |
494 | struct task_struct *p; |
495 | enum pid_type type; |
496 | struct pid *pid; |
497 | int group = 1; |
498 | |
499 | read_lock(&fown->lock); |
500 | |
501 | type = fown->pid_type; |
502 | if (type == PIDTYPE_MAX) { |
503 | group = 0; |
504 | type = PIDTYPE_PID; |
505 | } |
506 | |
507 | pid = fown->pid; |
508 | if (!pid) |
509 | goto out_unlock_fown; |
510 | |
511 | read_lock(&tasklist_lock); |
512 | do_each_pid_task(pid, type, p) { |
513 | send_sigio_to_task(p, fown, fd, band, group); |
514 | } while_each_pid_task(pid, type, p); |
515 | read_unlock(&tasklist_lock); |
516 | out_unlock_fown: |
517 | read_unlock(&fown->lock); |
518 | } |
519 | |
520 | static void send_sigurg_to_task(struct task_struct *p, |
521 | struct fown_struct *fown, int group) |
522 | { |
523 | if (sigio_perm(p, fown, SIGURG)) |
524 | do_send_sig_info(SIGURG, SEND_SIG_PRIV, p, group); |
525 | } |
526 | |
527 | int send_sigurg(struct fown_struct *fown) |
528 | { |
529 | struct task_struct *p; |
530 | enum pid_type type; |
531 | struct pid *pid; |
532 | int group = 1; |
533 | int ret = 0; |
534 | |
535 | read_lock(&fown->lock); |
536 | |
537 | type = fown->pid_type; |
538 | if (type == PIDTYPE_MAX) { |
539 | group = 0; |
540 | type = PIDTYPE_PID; |
541 | } |
542 | |
543 | pid = fown->pid; |
544 | if (!pid) |
545 | goto out_unlock_fown; |
546 | |
547 | ret = 1; |
548 | |
549 | read_lock(&tasklist_lock); |
550 | do_each_pid_task(pid, type, p) { |
551 | send_sigurg_to_task(p, fown, group); |
552 | } while_each_pid_task(pid, type, p); |
553 | read_unlock(&tasklist_lock); |
554 | out_unlock_fown: |
555 | read_unlock(&fown->lock); |
556 | return ret; |
557 | } |
558 | |
559 | static DEFINE_SPINLOCK(fasync_lock); |
560 | static struct kmem_cache *fasync_cache __read_mostly; |
561 | |
562 | static void fasync_free_rcu(struct rcu_head *head) |
563 | { |
564 | kmem_cache_free(fasync_cache, |
565 | container_of(head, struct fasync_struct, fa_rcu)); |
566 | } |
567 | |
568 | /* |
569 | * Remove a fasync entry. If successfully removed, return |
570 | * positive and clear the FASYNC flag. If no entry exists, |
571 | * do nothing and return 0. |
572 | * |
573 | * NOTE! It is very important that the FASYNC flag always |
574 | * match the state "is the filp on a fasync list". |
575 | * |
576 | */ |
577 | int fasync_remove_entry(struct file *filp, struct fasync_struct **fapp) |
578 | { |
579 | struct fasync_struct *fa, **fp; |
580 | int result = 0; |
581 | |
582 | spin_lock(&filp->f_lock); |
583 | spin_lock(&fasync_lock); |
584 | for (fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) { |
585 | if (fa->fa_file != filp) |
586 | continue; |
587 | |
588 | spin_lock_irq(&fa->fa_lock); |
589 | fa->fa_file = NULL; |
590 | spin_unlock_irq(&fa->fa_lock); |
591 | |
592 | *fp = fa->fa_next; |
593 | call_rcu(&fa->fa_rcu, fasync_free_rcu); |
594 | filp->f_flags &= ~FASYNC; |
595 | result = 1; |
596 | break; |
597 | } |
598 | spin_unlock(&fasync_lock); |
599 | spin_unlock(&filp->f_lock); |
600 | return result; |
601 | } |
602 | |
603 | struct fasync_struct *fasync_alloc(void) |
604 | { |
605 | return kmem_cache_alloc(fasync_cache, GFP_KERNEL); |
606 | } |
607 | |
608 | /* |
609 | * NOTE! This can be used only for unused fasync entries: |
610 | * entries that actually got inserted on the fasync list |
611 | * need to be released by rcu - see fasync_remove_entry. |
612 | */ |
613 | void fasync_free(struct fasync_struct *new) |
614 | { |
615 | kmem_cache_free(fasync_cache, new); |
616 | } |
617 | |
618 | /* |
619 | * Insert a new entry into the fasync list. Return the pointer to the |
620 | * old one if we didn't use the new one. |
621 | * |
622 | * NOTE! It is very important that the FASYNC flag always |
623 | * match the state "is the filp on a fasync list". |
624 | */ |
625 | struct fasync_struct *fasync_insert_entry(int fd, struct file *filp, struct fasync_struct **fapp, struct fasync_struct *new) |
626 | { |
627 | struct fasync_struct *fa, **fp; |
628 | |
629 | spin_lock(&filp->f_lock); |
630 | spin_lock(&fasync_lock); |
631 | for (fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) { |
632 | if (fa->fa_file != filp) |
633 | continue; |
634 | |
635 | spin_lock_irq(&fa->fa_lock); |
636 | fa->fa_fd = fd; |
637 | spin_unlock_irq(&fa->fa_lock); |
638 | goto out; |
639 | } |
640 | |
641 | spin_lock_init(&new->fa_lock); |
642 | new->magic = FASYNC_MAGIC; |
643 | new->fa_file = filp; |
644 | new->fa_fd = fd; |
645 | new->fa_next = *fapp; |
646 | rcu_assign_pointer(*fapp, new); |
647 | filp->f_flags |= FASYNC; |
648 | |
649 | out: |
650 | spin_unlock(&fasync_lock); |
651 | spin_unlock(&filp->f_lock); |
652 | return fa; |
653 | } |
654 | |
655 | /* |
656 | * Add a fasync entry. Return negative on error, positive if |
657 | * added, and zero if did nothing but change an existing one. |
658 | */ |
659 | static int fasync_add_entry(int fd, struct file *filp, struct fasync_struct **fapp) |
660 | { |
661 | struct fasync_struct *new; |
662 | |
663 | new = fasync_alloc(); |
664 | if (!new) |
665 | return -ENOMEM; |
666 | |
667 | /* |
668 | * fasync_insert_entry() returns the old (update) entry if |
669 | * it existed. |
670 | * |
671 | * So free the (unused) new entry and return 0 to let the |
672 | * caller know that we didn't add any new fasync entries. |
673 | */ |
674 | if (fasync_insert_entry(fd, filp, fapp, new)) { |
675 | fasync_free(new); |
676 | return 0; |
677 | } |
678 | |
679 | return 1; |
680 | } |
681 | |
682 | /* |
683 | * fasync_helper() is used by almost all character device drivers |
684 | * to set up the fasync queue, and for regular files by the file |
685 | * lease code. It returns negative on error, 0 if it did no changes |
686 | * and positive if it added/deleted the entry. |
687 | */ |
688 | int fasync_helper(int fd, struct file * filp, int on, struct fasync_struct **fapp) |
689 | { |
690 | if (!on) |
691 | return fasync_remove_entry(filp, fapp); |
692 | return fasync_add_entry(fd, filp, fapp); |
693 | } |
694 | |
695 | EXPORT_SYMBOL(fasync_helper); |
696 | |
697 | /* |
698 | * rcu_read_lock() is held |
699 | */ |
700 | static void kill_fasync_rcu(struct fasync_struct *fa, int sig, int band) |
701 | { |
702 | while (fa) { |
703 | struct fown_struct *fown; |
704 | unsigned long flags; |
705 | |
706 | if (fa->magic != FASYNC_MAGIC) { |
707 | printk(KERN_ERR "kill_fasync: bad magic number in " |
708 | "fasync_struct!\n"); |
709 | return; |
710 | } |
711 | spin_lock_irqsave(&fa->fa_lock, flags); |
712 | if (fa->fa_file) { |
713 | fown = &fa->fa_file->f_owner; |
714 | /* Don't send SIGURG to processes which have not set a |
715 | queued signum: SIGURG has its own default signalling |
716 | mechanism. */ |
717 | if (!(sig == SIGURG && fown->signum == 0)) |
718 | send_sigio(fown, fa->fa_fd, band); |
719 | } |
720 | spin_unlock_irqrestore(&fa->fa_lock, flags); |
721 | fa = rcu_dereference(fa->fa_next); |
722 | } |
723 | } |
724 | |
725 | void kill_fasync(struct fasync_struct **fp, int sig, int band) |
726 | { |
727 | /* First a quick test without locking: usually |
728 | * the list is empty. |
729 | */ |
730 | if (*fp) { |
731 | rcu_read_lock(); |
732 | kill_fasync_rcu(rcu_dereference(*fp), sig, band); |
733 | rcu_read_unlock(); |
734 | } |
735 | } |
736 | EXPORT_SYMBOL(kill_fasync); |
737 | |
738 | static int __init fcntl_init(void) |
739 | { |
740 | /* |
741 | * Please add new bits here to ensure allocation uniqueness. |
742 | * Exceptions: O_NONBLOCK is a two bit define on parisc; O_NDELAY |
743 | * is defined as O_NONBLOCK on some platforms and not on others. |
744 | */ |
745 | BUILD_BUG_ON(20 - 1 /* for O_RDONLY being 0 */ != HWEIGHT32( |
746 | O_RDONLY | O_WRONLY | O_RDWR | |
747 | O_CREAT | O_EXCL | O_NOCTTY | |
748 | O_TRUNC | O_APPEND | /* O_NONBLOCK | */ |
749 | __O_SYNC | O_DSYNC | FASYNC | |
750 | O_DIRECT | O_LARGEFILE | O_DIRECTORY | |
751 | O_NOFOLLOW | O_NOATIME | O_CLOEXEC | |
752 | __FMODE_EXEC | O_PATH | __O_TMPFILE |
753 | )); |
754 | |
755 | fasync_cache = kmem_cache_create("fasync_cache", |
756 | sizeof(struct fasync_struct), 0, SLAB_PANIC, NULL); |
757 | return 0; |
758 | } |
759 | |
760 | module_init(fcntl_init) |
761 |
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javiroman/ks7010
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v2.6.34-rc5
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