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CommitLineData
1da177e4
LT
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>
9f3acc31 12#include <linux/fdtable.h>
16f7e0fe 13#include <linux/capability.h>
1da177e4 14#include <linux/dnotify.h>
1da177e4
LT
15#include <linux/slab.h>
16#include <linux/module.h>
35f3d14d 17#include <linux/pipe_fs_i.h>
1da177e4
LT
18#include <linux/security.h>
19#include <linux/ptrace.h>
7ed20e1a 20#include <linux/signal.h>
ab2af1f5 21#include <linux/rcupdate.h>
b488893a 22#include <linux/pid_namespace.h>
1d151c33 23#include <linux/user_namespace.h>
40e041a2 24#include <linux/shmem_fs.h>
1da177e4
LT
25
26#include <asm/poll.h>
27#include <asm/siginfo.h>
28#include <asm/uaccess.h>
29
76398425 30#define SETFL_MASK (O_APPEND | O_NONBLOCK | O_NDELAY | O_DIRECT | O_NOATIME)
1da177e4
LT
31
32static int setfl(int fd, struct file * filp, unsigned long arg)
33{
496ad9aa 34 struct inode * inode = file_inode(filp);
1da177e4
LT
35 int error = 0;
36
7d95c8f2 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))
1da177e4
LT
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))
2e149670 46 if (!inode_owner_or_capable(inode))
1da177e4
LT
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 if (arg & O_DIRECT) {
55 if (!filp->f_mapping || !filp->f_mapping->a_ops ||
56 !filp->f_mapping->a_ops->direct_IO)
57 return -EINVAL;
58 }
59
72c2d531 60 if (filp->f_op->check_flags)
1da177e4
LT
61 error = filp->f_op->check_flags(arg);
62 if (error)
63 return error;
64
218d11a8 65 /*
76398425 66 * ->fasync() is responsible for setting the FASYNC bit.
218d11a8 67 */
72c2d531 68 if (((arg ^ filp->f_flags) & FASYNC) && filp->f_op->fasync) {
76398425
JC
69 error = filp->f_op->fasync(fd, filp, (arg & FASYNC) != 0);
70 if (error < 0)
71 goto out;
60aa4924
JC
72 if (error > 0)
73 error = 0;
1da177e4 74 }
db1dd4d3 75 spin_lock(&filp->f_lock);
1da177e4 76 filp->f_flags = (arg & SETFL_MASK) | (filp->f_flags & ~SETFL_MASK);
db1dd4d3 77 spin_unlock(&filp->f_lock);
76398425 78
1da177e4 79 out:
1da177e4
LT
80 return error;
81}
82
609d7fa9 83static void f_modown(struct file *filp, struct pid *pid, enum pid_type type,
2f38d70f 84 int force)
1da177e4 85{
80e1e823 86 write_lock_irq(&filp->f_owner.lock);
1da177e4 87 if (force || !filp->f_owner.pid) {
609d7fa9
EB
88 put_pid(filp->f_owner.pid);
89 filp->f_owner.pid = get_pid(pid);
90 filp->f_owner.pid_type = type;
2f38d70f
ON
91
92 if (pid) {
93 const struct cred *cred = current_cred();
94 filp->f_owner.uid = cred->uid;
95 filp->f_owner.euid = cred->euid;
96 }
1da177e4 97 }
80e1e823 98 write_unlock_irq(&filp->f_owner.lock);
1da177e4
LT
99}
100
e0b93edd 101void __f_setown(struct file *filp, struct pid *pid, enum pid_type type,
609d7fa9 102 int force)
1da177e4 103{
e0b93edd 104 security_file_set_fowner(filp);
2f38d70f 105 f_modown(filp, pid, type, force);
1da177e4 106}
609d7fa9 107EXPORT_SYMBOL(__f_setown);
1da177e4 108
e0b93edd 109void f_setown(struct file *filp, unsigned long arg, int force)
609d7fa9
EB
110{
111 enum pid_type type;
112 struct pid *pid;
113 int who = arg;
609d7fa9
EB
114 type = PIDTYPE_PID;
115 if (who < 0) {
116 type = PIDTYPE_PGID;
117 who = -who;
118 }
119 rcu_read_lock();
b488893a 120 pid = find_vpid(who);
e0b93edd 121 __f_setown(filp, pid, type, force);
609d7fa9 122 rcu_read_unlock();
609d7fa9 123}
1da177e4
LT
124EXPORT_SYMBOL(f_setown);
125
126void f_delown(struct file *filp)
127{
2f38d70f 128 f_modown(filp, NULL, PIDTYPE_PID, 1);
609d7fa9
EB
129}
130
131pid_t f_getown(struct file *filp)
132{
133 pid_t pid;
43fa1adb 134 read_lock(&filp->f_owner.lock);
6c5f3e7b 135 pid = pid_vnr(filp->f_owner.pid);
609d7fa9
EB
136 if (filp->f_owner.pid_type == PIDTYPE_PGID)
137 pid = -pid;
43fa1adb 138 read_unlock(&filp->f_owner.lock);
609d7fa9 139 return pid;
1da177e4
LT
140}
141
ba0a6c9f
PZ
142static int f_setown_ex(struct file *filp, unsigned long arg)
143{
63784dd0 144 struct f_owner_ex __user *owner_p = (void __user *)arg;
ba0a6c9f
PZ
145 struct f_owner_ex owner;
146 struct pid *pid;
147 int type;
148 int ret;
149
150 ret = copy_from_user(&owner, owner_p, sizeof(owner));
151 if (ret)
5b54470d 152 return -EFAULT;
ba0a6c9f
PZ
153
154 switch (owner.type) {
155 case F_OWNER_TID:
156 type = PIDTYPE_MAX;
157 break;
158
159 case F_OWNER_PID:
160 type = PIDTYPE_PID;
161 break;
162
978b4053 163 case F_OWNER_PGRP:
ba0a6c9f
PZ
164 type = PIDTYPE_PGID;
165 break;
166
167 default:
168 return -EINVAL;
169 }
170
171 rcu_read_lock();
172 pid = find_vpid(owner.pid);
173 if (owner.pid && !pid)
174 ret = -ESRCH;
175 else
e0b93edd 176 __f_setown(filp, pid, type, 1);
ba0a6c9f
PZ
177 rcu_read_unlock();
178
179 return ret;
180}
181
182static int f_getown_ex(struct file *filp, unsigned long arg)
183{
63784dd0 184 struct f_owner_ex __user *owner_p = (void __user *)arg;
ba0a6c9f
PZ
185 struct f_owner_ex owner;
186 int ret = 0;
187
188 read_lock(&filp->f_owner.lock);
189 owner.pid = pid_vnr(filp->f_owner.pid);
190 switch (filp->f_owner.pid_type) {
191 case PIDTYPE_MAX:
192 owner.type = F_OWNER_TID;
193 break;
194
195 case PIDTYPE_PID:
196 owner.type = F_OWNER_PID;
197 break;
198
199 case PIDTYPE_PGID:
978b4053 200 owner.type = F_OWNER_PGRP;
ba0a6c9f
PZ
201 break;
202
203 default:
204 WARN_ON(1);
205 ret = -EINVAL;
206 break;
207 }
208 read_unlock(&filp->f_owner.lock);
209
5b54470d 210 if (!ret) {
ba0a6c9f 211 ret = copy_to_user(owner_p, &owner, sizeof(owner));
5b54470d
DC
212 if (ret)
213 ret = -EFAULT;
214 }
ba0a6c9f
PZ
215 return ret;
216}
217
1d151c33
CG
218#ifdef CONFIG_CHECKPOINT_RESTORE
219static int f_getowner_uids(struct file *filp, unsigned long arg)
220{
221 struct user_namespace *user_ns = current_user_ns();
63784dd0 222 uid_t __user *dst = (void __user *)arg;
1d151c33
CG
223 uid_t src[2];
224 int err;
225
226 read_lock(&filp->f_owner.lock);
227 src[0] = from_kuid(user_ns, filp->f_owner.uid);
228 src[1] = from_kuid(user_ns, filp->f_owner.euid);
229 read_unlock(&filp->f_owner.lock);
230
231 err = put_user(src[0], &dst[0]);
232 err |= put_user(src[1], &dst[1]);
233
234 return err;
235}
236#else
237static int f_getowner_uids(struct file *filp, unsigned long arg)
238{
239 return -EINVAL;
240}
241#endif
242
1da177e4
LT
243static long do_fcntl(int fd, unsigned int cmd, unsigned long arg,
244 struct file *filp)
245{
246 long err = -EINVAL;
247
248 switch (cmd) {
249 case F_DUPFD:
fe17f22d
AV
250 err = f_dupfd(arg, filp, 0);
251 break;
22d2b35b 252 case F_DUPFD_CLOEXEC:
12197718 253 err = f_dupfd(arg, filp, O_CLOEXEC);
1da177e4
LT
254 break;
255 case F_GETFD:
256 err = get_close_on_exec(fd) ? FD_CLOEXEC : 0;
257 break;
258 case F_SETFD:
259 err = 0;
260 set_close_on_exec(fd, arg & FD_CLOEXEC);
261 break;
262 case F_GETFL:
263 err = filp->f_flags;
264 break;
265 case F_SETFL:
266 err = setfl(fd, filp, arg);
267 break;
5d50ffd7
JL
268#if BITS_PER_LONG != 32
269 /* 32-bit arches must use fcntl64() */
0d3f7a2d 270 case F_OFD_GETLK:
5d50ffd7 271#endif
1da177e4 272 case F_GETLK:
c1e62b8f 273 err = fcntl_getlk(filp, cmd, (struct flock __user *) arg);
1da177e4 274 break;
5d50ffd7
JL
275#if BITS_PER_LONG != 32
276 /* 32-bit arches must use fcntl64() */
0d3f7a2d
JL
277 case F_OFD_SETLK:
278 case F_OFD_SETLKW:
5d50ffd7
JL
279#endif
280 /* Fallthrough */
1da177e4
LT
281 case F_SETLK:
282 case F_SETLKW:
c293621b 283 err = fcntl_setlk(fd, filp, cmd, (struct flock __user *) arg);
1da177e4
LT
284 break;
285 case F_GETOWN:
286 /*
287 * XXX If f_owner is a process group, the
288 * negative return value will get converted
289 * into an error. Oops. If we keep the
290 * current syscall conventions, the only way
291 * to fix this will be in libc.
292 */
609d7fa9 293 err = f_getown(filp);
1da177e4
LT
294 force_successful_syscall_return();
295 break;
296 case F_SETOWN:
e0b93edd
JL
297 f_setown(filp, arg, 1);
298 err = 0;
1da177e4 299 break;
ba0a6c9f
PZ
300 case F_GETOWN_EX:
301 err = f_getown_ex(filp, arg);
302 break;
303 case F_SETOWN_EX:
304 err = f_setown_ex(filp, arg);
305 break;
1d151c33
CG
306 case F_GETOWNER_UIDS:
307 err = f_getowner_uids(filp, arg);
308 break;
1da177e4
LT
309 case F_GETSIG:
310 err = filp->f_owner.signum;
311 break;
312 case F_SETSIG:
313 /* arg == 0 restores default behaviour. */
7ed20e1a 314 if (!valid_signal(arg)) {
1da177e4
LT
315 break;
316 }
317 err = 0;
318 filp->f_owner.signum = arg;
319 break;
320 case F_GETLEASE:
321 err = fcntl_getlease(filp);
322 break;
323 case F_SETLEASE:
324 err = fcntl_setlease(fd, filp, arg);
325 break;
326 case F_NOTIFY:
327 err = fcntl_dirnotify(fd, filp, arg);
328 break;
35f3d14d
JA
329 case F_SETPIPE_SZ:
330 case F_GETPIPE_SZ:
331 err = pipe_fcntl(filp, cmd, arg);
332 break;
40e041a2
DH
333 case F_ADD_SEALS:
334 case F_GET_SEALS:
335 err = shmem_fcntl(filp, cmd, arg);
336 break;
1da177e4
LT
337 default:
338 break;
339 }
340 return err;
341}
342
1abf0c71
AV
343static int check_fcntl_cmd(unsigned cmd)
344{
345 switch (cmd) {
346 case F_DUPFD:
347 case F_DUPFD_CLOEXEC:
348 case F_GETFD:
349 case F_SETFD:
350 case F_GETFL:
351 return 1;
352 }
353 return 0;
354}
355
a26eab24 356SYSCALL_DEFINE3(fcntl, unsigned int, fd, unsigned int, cmd, unsigned long, arg)
1da177e4 357{
2903ff01 358 struct fd f = fdget_raw(fd);
1da177e4
LT
359 long err = -EBADF;
360
2903ff01 361 if (!f.file)
1da177e4
LT
362 goto out;
363
2903ff01 364 if (unlikely(f.file->f_mode & FMODE_PATH)) {
545ec2c7
AV
365 if (!check_fcntl_cmd(cmd))
366 goto out1;
1abf0c71
AV
367 }
368
2903ff01 369 err = security_file_fcntl(f.file, cmd, arg);
545ec2c7 370 if (!err)
2903ff01 371 err = do_fcntl(fd, cmd, arg, f.file);
1da177e4 372
545ec2c7 373out1:
2903ff01 374 fdput(f);
1da177e4
LT
375out:
376 return err;
377}
378
379#if BITS_PER_LONG == 32
a26eab24
HC
380SYSCALL_DEFINE3(fcntl64, unsigned int, fd, unsigned int, cmd,
381 unsigned long, arg)
1da177e4 382{
2903ff01 383 struct fd f = fdget_raw(fd);
545ec2c7 384 long err = -EBADF;
1da177e4 385
2903ff01 386 if (!f.file)
1da177e4
LT
387 goto out;
388
2903ff01 389 if (unlikely(f.file->f_mode & FMODE_PATH)) {
545ec2c7
AV
390 if (!check_fcntl_cmd(cmd))
391 goto out1;
1abf0c71
AV
392 }
393
2903ff01 394 err = security_file_fcntl(f.file, cmd, arg);
545ec2c7
AV
395 if (err)
396 goto out1;
1da177e4
LT
397
398 switch (cmd) {
5d50ffd7 399 case F_GETLK64:
0d3f7a2d 400 case F_OFD_GETLK:
5d50ffd7
JL
401 err = fcntl_getlk64(f.file, cmd, (struct flock64 __user *) arg);
402 break;
403 case F_SETLK64:
404 case F_SETLKW64:
0d3f7a2d
JL
405 case F_OFD_SETLK:
406 case F_OFD_SETLKW:
5d50ffd7
JL
407 err = fcntl_setlk64(fd, f.file, cmd,
408 (struct flock64 __user *) arg);
409 break;
410 default:
411 err = do_fcntl(fd, cmd, arg, f.file);
412 break;
1da177e4 413 }
545ec2c7 414out1:
2903ff01 415 fdput(f);
1da177e4
LT
416out:
417 return err;
418}
419#endif
420
421/* Table to convert sigio signal codes into poll band bitmaps */
422
fa3536cc 423static const long band_table[NSIGPOLL] = {
1da177e4
LT
424 POLLIN | POLLRDNORM, /* POLL_IN */
425 POLLOUT | POLLWRNORM | POLLWRBAND, /* POLL_OUT */
426 POLLIN | POLLRDNORM | POLLMSG, /* POLL_MSG */
427 POLLERR, /* POLL_ERR */
428 POLLPRI | POLLRDBAND, /* POLL_PRI */
429 POLLHUP | POLLERR /* POLL_HUP */
430};
431
432static inline int sigio_perm(struct task_struct *p,
433 struct fown_struct *fown, int sig)
434{
c69e8d9c
DH
435 const struct cred *cred;
436 int ret;
437
438 rcu_read_lock();
439 cred = __task_cred(p);
8e96e3b7
EB
440 ret = ((uid_eq(fown->euid, GLOBAL_ROOT_UID) ||
441 uid_eq(fown->euid, cred->suid) || uid_eq(fown->euid, cred->uid) ||
442 uid_eq(fown->uid, cred->suid) || uid_eq(fown->uid, cred->uid)) &&
c69e8d9c
DH
443 !security_file_send_sigiotask(p, fown, sig));
444 rcu_read_unlock();
445 return ret;
1da177e4
LT
446}
447
448static void send_sigio_to_task(struct task_struct *p,
8eeee4e2 449 struct fown_struct *fown,
ba0a6c9f 450 int fd, int reason, int group)
1da177e4 451{
8eeee4e2
ON
452 /*
453 * F_SETSIG can change ->signum lockless in parallel, make
454 * sure we read it once and use the same value throughout.
455 */
456 int signum = ACCESS_ONCE(fown->signum);
457
458 if (!sigio_perm(p, fown, signum))
1da177e4
LT
459 return;
460
8eeee4e2 461 switch (signum) {
1da177e4
LT
462 siginfo_t si;
463 default:
464 /* Queue a rt signal with the appropriate fd as its
465 value. We use SI_SIGIO as the source, not
466 SI_KERNEL, since kernel signals always get
467 delivered even if we can't queue. Failure to
468 queue in this case _should_ be reported; we fall
469 back to SIGIO in that case. --sct */
8eeee4e2 470 si.si_signo = signum;
1da177e4
LT
471 si.si_errno = 0;
472 si.si_code = reason;
473 /* Make sure we are called with one of the POLL_*
474 reasons, otherwise we could leak kernel stack into
475 userspace. */
f6298aab 476 BUG_ON((reason & __SI_MASK) != __SI_POLL);
1da177e4
LT
477 if (reason - POLL_IN >= NSIGPOLL)
478 si.si_band = ~0L;
479 else
480 si.si_band = band_table[reason - POLL_IN];
481 si.si_fd = fd;
ba0a6c9f 482 if (!do_send_sig_info(signum, &si, p, group))
1da177e4
LT
483 break;
484 /* fall-through: fall back on the old plain SIGIO signal */
485 case 0:
ba0a6c9f 486 do_send_sig_info(SIGIO, SEND_SIG_PRIV, p, group);
1da177e4
LT
487 }
488}
489
490void send_sigio(struct fown_struct *fown, int fd, int band)
491{
492 struct task_struct *p;
609d7fa9
EB
493 enum pid_type type;
494 struct pid *pid;
ba0a6c9f 495 int group = 1;
1da177e4
LT
496
497 read_lock(&fown->lock);
ba0a6c9f 498
609d7fa9 499 type = fown->pid_type;
ba0a6c9f
PZ
500 if (type == PIDTYPE_MAX) {
501 group = 0;
502 type = PIDTYPE_PID;
503 }
504
1da177e4
LT
505 pid = fown->pid;
506 if (!pid)
507 goto out_unlock_fown;
508
509 read_lock(&tasklist_lock);
609d7fa9 510 do_each_pid_task(pid, type, p) {
ba0a6c9f 511 send_sigio_to_task(p, fown, fd, band, group);
609d7fa9 512 } while_each_pid_task(pid, type, p);
1da177e4
LT
513 read_unlock(&tasklist_lock);
514 out_unlock_fown:
515 read_unlock(&fown->lock);
516}
517
518static void send_sigurg_to_task(struct task_struct *p,
ba0a6c9f 519 struct fown_struct *fown, int group)
1da177e4
LT
520{
521 if (sigio_perm(p, fown, SIGURG))
ba0a6c9f 522 do_send_sig_info(SIGURG, SEND_SIG_PRIV, p, group);
1da177e4
LT
523}
524
525int send_sigurg(struct fown_struct *fown)
526{
527 struct task_struct *p;
609d7fa9
EB
528 enum pid_type type;
529 struct pid *pid;
ba0a6c9f 530 int group = 1;
609d7fa9 531 int ret = 0;
1da177e4
LT
532
533 read_lock(&fown->lock);
ba0a6c9f 534
609d7fa9 535 type = fown->pid_type;
ba0a6c9f
PZ
536 if (type == PIDTYPE_MAX) {
537 group = 0;
538 type = PIDTYPE_PID;
539 }
540
1da177e4
LT
541 pid = fown->pid;
542 if (!pid)
543 goto out_unlock_fown;
544
545 ret = 1;
546
547 read_lock(&tasklist_lock);
609d7fa9 548 do_each_pid_task(pid, type, p) {
ba0a6c9f 549 send_sigurg_to_task(p, fown, group);
609d7fa9 550 } while_each_pid_task(pid, type, p);
1da177e4
LT
551 read_unlock(&tasklist_lock);
552 out_unlock_fown:
553 read_unlock(&fown->lock);
554 return ret;
555}
556
989a2979 557static DEFINE_SPINLOCK(fasync_lock);
e18b890b 558static struct kmem_cache *fasync_cache __read_mostly;
1da177e4 559
989a2979
ED
560static void fasync_free_rcu(struct rcu_head *head)
561{
562 kmem_cache_free(fasync_cache,
563 container_of(head, struct fasync_struct, fa_rcu));
564}
565
1da177e4 566/*
53281b6d
LT
567 * Remove a fasync entry. If successfully removed, return
568 * positive and clear the FASYNC flag. If no entry exists,
569 * do nothing and return 0.
570 *
571 * NOTE! It is very important that the FASYNC flag always
572 * match the state "is the filp on a fasync list".
573 *
1da177e4 574 */
f7347ce4 575int fasync_remove_entry(struct file *filp, struct fasync_struct **fapp)
1da177e4
LT
576{
577 struct fasync_struct *fa, **fp;
1da177e4
LT
578 int result = 0;
579
53281b6d 580 spin_lock(&filp->f_lock);
989a2979 581 spin_lock(&fasync_lock);
53281b6d
LT
582 for (fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) {
583 if (fa->fa_file != filp)
584 continue;
989a2979
ED
585
586 spin_lock_irq(&fa->fa_lock);
587 fa->fa_file = NULL;
588 spin_unlock_irq(&fa->fa_lock);
589
53281b6d 590 *fp = fa->fa_next;
989a2979 591 call_rcu(&fa->fa_rcu, fasync_free_rcu);
53281b6d
LT
592 filp->f_flags &= ~FASYNC;
593 result = 1;
594 break;
1da177e4 595 }
989a2979 596 spin_unlock(&fasync_lock);
53281b6d
LT
597 spin_unlock(&filp->f_lock);
598 return result;
599}
600
f7347ce4
LT
601struct fasync_struct *fasync_alloc(void)
602{
603 return kmem_cache_alloc(fasync_cache, GFP_KERNEL);
604}
605
53281b6d 606/*
f7347ce4
LT
607 * NOTE! This can be used only for unused fasync entries:
608 * entries that actually got inserted on the fasync list
609 * need to be released by rcu - see fasync_remove_entry.
53281b6d 610 */
f7347ce4 611void fasync_free(struct fasync_struct *new)
53281b6d 612{
f7347ce4
LT
613 kmem_cache_free(fasync_cache, new);
614}
53281b6d 615
f7347ce4
LT
616/*
617 * Insert a new entry into the fasync list. Return the pointer to the
618 * old one if we didn't use the new one.
55f335a8
LT
619 *
620 * NOTE! It is very important that the FASYNC flag always
621 * match the state "is the filp on a fasync list".
f7347ce4
LT
622 */
623struct fasync_struct *fasync_insert_entry(int fd, struct file *filp, struct fasync_struct **fapp, struct fasync_struct *new)
624{
625 struct fasync_struct *fa, **fp;
4a6a4499 626
4a6a4499 627 spin_lock(&filp->f_lock);
989a2979 628 spin_lock(&fasync_lock);
1da177e4 629 for (fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) {
53281b6d
LT
630 if (fa->fa_file != filp)
631 continue;
989a2979
ED
632
633 spin_lock_irq(&fa->fa_lock);
53281b6d 634 fa->fa_fd = fd;
989a2979 635 spin_unlock_irq(&fa->fa_lock);
53281b6d 636 goto out;
1da177e4
LT
637 }
638
989a2979 639 spin_lock_init(&new->fa_lock);
53281b6d
LT
640 new->magic = FASYNC_MAGIC;
641 new->fa_file = filp;
642 new->fa_fd = fd;
643 new->fa_next = *fapp;
989a2979 644 rcu_assign_pointer(*fapp, new);
53281b6d
LT
645 filp->f_flags |= FASYNC;
646
1da177e4 647out:
989a2979 648 spin_unlock(&fasync_lock);
4a6a4499 649 spin_unlock(&filp->f_lock);
f7347ce4
LT
650 return fa;
651}
652
653/*
654 * Add a fasync entry. Return negative on error, positive if
655 * added, and zero if did nothing but change an existing one.
f7347ce4
LT
656 */
657static int fasync_add_entry(int fd, struct file *filp, struct fasync_struct **fapp)
658{
659 struct fasync_struct *new;
660
661 new = fasync_alloc();
662 if (!new)
663 return -ENOMEM;
664
665 /*
666 * fasync_insert_entry() returns the old (update) entry if
667 * it existed.
668 *
669 * So free the (unused) new entry and return 0 to let the
670 * caller know that we didn't add any new fasync entries.
671 */
672 if (fasync_insert_entry(fd, filp, fapp, new)) {
673 fasync_free(new);
674 return 0;
675 }
676
677 return 1;
1da177e4
LT
678}
679
53281b6d
LT
680/*
681 * fasync_helper() is used by almost all character device drivers
682 * to set up the fasync queue, and for regular files by the file
683 * lease code. It returns negative on error, 0 if it did no changes
684 * and positive if it added/deleted the entry.
685 */
686int fasync_helper(int fd, struct file * filp, int on, struct fasync_struct **fapp)
687{
688 if (!on)
689 return fasync_remove_entry(filp, fapp);
690 return fasync_add_entry(fd, filp, fapp);
691}
692
1da177e4
LT
693EXPORT_SYMBOL(fasync_helper);
694
989a2979
ED
695/*
696 * rcu_read_lock() is held
697 */
698static void kill_fasync_rcu(struct fasync_struct *fa, int sig, int band)
1da177e4
LT
699{
700 while (fa) {
989a2979 701 struct fown_struct *fown;
f4985dc7
AM
702 unsigned long flags;
703
1da177e4
LT
704 if (fa->magic != FASYNC_MAGIC) {
705 printk(KERN_ERR "kill_fasync: bad magic number in "
706 "fasync_struct!\n");
707 return;
708 }
f4985dc7 709 spin_lock_irqsave(&fa->fa_lock, flags);
989a2979
ED
710 if (fa->fa_file) {
711 fown = &fa->fa_file->f_owner;
712 /* Don't send SIGURG to processes which have not set a
713 queued signum: SIGURG has its own default signalling
714 mechanism. */
715 if (!(sig == SIGURG && fown->signum == 0))
716 send_sigio(fown, fa->fa_fd, band);
717 }
f4985dc7 718 spin_unlock_irqrestore(&fa->fa_lock, flags);
989a2979 719 fa = rcu_dereference(fa->fa_next);
1da177e4
LT
720 }
721}
722
1da177e4
LT
723void kill_fasync(struct fasync_struct **fp, int sig, int band)
724{
725 /* First a quick test without locking: usually
726 * the list is empty.
727 */
728 if (*fp) {
989a2979
ED
729 rcu_read_lock();
730 kill_fasync_rcu(rcu_dereference(*fp), sig, band);
731 rcu_read_unlock();
1da177e4
LT
732 }
733}
734EXPORT_SYMBOL(kill_fasync);
735
454eedb8 736static int __init fcntl_init(void)
1da177e4 737{
3ab04d5c
JB
738 /*
739 * Please add new bits here to ensure allocation uniqueness.
740 * Exceptions: O_NONBLOCK is a two bit define on parisc; O_NDELAY
741 * is defined as O_NONBLOCK on some platforms and not on others.
742 */
75069f2b 743 BUILD_BUG_ON(21 - 1 /* for O_RDONLY being 0 */ != HWEIGHT32(
454eedb8
WF
744 O_RDONLY | O_WRONLY | O_RDWR |
745 O_CREAT | O_EXCL | O_NOCTTY |
3ab04d5c 746 O_TRUNC | O_APPEND | /* O_NONBLOCK | */
454eedb8
WF
747 __O_SYNC | O_DSYNC | FASYNC |
748 O_DIRECT | O_LARGEFILE | O_DIRECTORY |
749 O_NOFOLLOW | O_NOATIME | O_CLOEXEC |
75069f2b
DD
750 __FMODE_EXEC | O_PATH | __O_TMPFILE |
751 __FMODE_NONOTIFY
454eedb8
WF
752 ));
753
1da177e4 754 fasync_cache = kmem_cache_create("fasync_cache",
20c2df83 755 sizeof(struct fasync_struct), 0, SLAB_PANIC, NULL);
1da177e4
LT
756 return 0;
757}
758
454eedb8 759module_init(fcntl_init)