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