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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>
1da177e4
LT
24
25#include <asm/poll.h>
26#include <asm/siginfo.h>
27#include <asm/uaccess.h>
28
fc9b52cd 29void set_close_on_exec(unsigned int fd, int flag)
1da177e4
LT
30{
31 struct files_struct *files = current->files;
badf1662 32 struct fdtable *fdt;
1da177e4 33 spin_lock(&files->file_lock);
badf1662 34 fdt = files_fdtable(files);
1da177e4 35 if (flag)
1dce27c5 36 __set_close_on_exec(fd, fdt);
1da177e4 37 else
1dce27c5 38 __clear_close_on_exec(fd, fdt);
1da177e4
LT
39 spin_unlock(&files->file_lock);
40}
41
1dce27c5 42static bool get_close_on_exec(unsigned int fd)
1da177e4
LT
43{
44 struct files_struct *files = current->files;
badf1662 45 struct fdtable *fdt;
1dce27c5 46 bool res;
b835996f 47 rcu_read_lock();
badf1662 48 fdt = files_fdtable(files);
1dce27c5 49 res = close_on_exec(fd, fdt);
b835996f 50 rcu_read_unlock();
1da177e4
LT
51 return res;
52}
53
a26eab24 54SYSCALL_DEFINE3(dup3, unsigned int, oldfd, unsigned int, newfd, int, flags)
1da177e4
LT
55{
56 int err = -EBADF;
57 struct file * file, *tofree;
58 struct files_struct * files = current->files;
badf1662 59 struct fdtable *fdt;
1da177e4 60
336dd1f7
UD
61 if ((flags & ~O_CLOEXEC) != 0)
62 return -EINVAL;
63
6c5d0512
AV
64 if (unlikely(oldfd == newfd))
65 return -EINVAL;
66
1da177e4 67 spin_lock(&files->file_lock);
1da177e4 68 err = expand_files(files, newfd);
1b7e190b
AV
69 file = fcheck(oldfd);
70 if (unlikely(!file))
71 goto Ebadf;
4e1e018e
AV
72 if (unlikely(err < 0)) {
73 if (err == -EMFILE)
1b7e190b
AV
74 goto Ebadf;
75 goto out_unlock;
4e1e018e 76 }
1b7e190b
AV
77 /*
78 * We need to detect attempts to do dup2() over allocated but still
79 * not finished descriptor. NB: OpenBSD avoids that at the price of
80 * extra work in their equivalent of fget() - they insert struct
81 * file immediately after grabbing descriptor, mark it larval if
82 * more work (e.g. actual opening) is needed and make sure that
83 * fget() treats larval files as absent. Potentially interesting,
84 * but while extra work in fget() is trivial, locking implications
85 * and amount of surgery on open()-related paths in VFS are not.
86 * FreeBSD fails with -EBADF in the same situation, NetBSD "solution"
87 * deadlocks in rather amusing ways, AFAICS. All of that is out of
88 * scope of POSIX or SUS, since neither considers shared descriptor
89 * tables and this condition does not arise without those.
90 */
1da177e4 91 err = -EBUSY;
badf1662
DS
92 fdt = files_fdtable(files);
93 tofree = fdt->fd[newfd];
1dce27c5 94 if (!tofree && fd_is_open(newfd, fdt))
1b7e190b
AV
95 goto out_unlock;
96 get_file(file);
ab2af1f5 97 rcu_assign_pointer(fdt->fd[newfd], file);
1dce27c5 98 __set_open_fd(newfd, fdt);
336dd1f7 99 if (flags & O_CLOEXEC)
1dce27c5 100 __set_close_on_exec(newfd, fdt);
336dd1f7 101 else
1dce27c5 102 __clear_close_on_exec(newfd, fdt);
1da177e4
LT
103 spin_unlock(&files->file_lock);
104
105 if (tofree)
106 filp_close(tofree, files);
1da177e4 107
1b7e190b
AV
108 return newfd;
109
110Ebadf:
111 err = -EBADF;
112out_unlock:
1da177e4 113 spin_unlock(&files->file_lock);
1b7e190b 114 return err;
1da177e4 115}
336dd1f7 116
a26eab24 117SYSCALL_DEFINE2(dup2, unsigned int, oldfd, unsigned int, newfd)
336dd1f7 118{
6c5d0512
AV
119 if (unlikely(newfd == oldfd)) { /* corner case */
120 struct files_struct *files = current->files;
2b79bc4f
JM
121 int retval = oldfd;
122
6c5d0512
AV
123 rcu_read_lock();
124 if (!fcheck_files(files, oldfd))
2b79bc4f 125 retval = -EBADF;
6c5d0512 126 rcu_read_unlock();
2b79bc4f 127 return retval;
6c5d0512 128 }
336dd1f7
UD
129 return sys_dup3(oldfd, newfd, 0);
130}
1da177e4 131
a26eab24 132SYSCALL_DEFINE1(dup, unsigned int, fildes)
1da177e4
LT
133{
134 int ret = -EBADF;
1abf0c71 135 struct file *file = fget_raw(fildes);
1027abe8
AV
136
137 if (file) {
138 ret = get_unused_fd();
139 if (ret >= 0)
140 fd_install(ret, file);
141 else
142 fput(file);
143 }
1da177e4
LT
144 return ret;
145}
146
76398425 147#define SETFL_MASK (O_APPEND | O_NONBLOCK | O_NDELAY | O_DIRECT | O_NOATIME)
1da177e4
LT
148
149static int setfl(int fd, struct file * filp, unsigned long arg)
150{
0f7fc9e4 151 struct inode * inode = filp->f_path.dentry->d_inode;
1da177e4
LT
152 int error = 0;
153
7d95c8f2 154 /*
155 * O_APPEND cannot be cleared if the file is marked as append-only
156 * and the file is open for write.
157 */
158 if (((arg ^ filp->f_flags) & O_APPEND) && IS_APPEND(inode))
1da177e4
LT
159 return -EPERM;
160
161 /* O_NOATIME can only be set by the owner or superuser */
162 if ((arg & O_NOATIME) && !(filp->f_flags & O_NOATIME))
2e149670 163 if (!inode_owner_or_capable(inode))
1da177e4
LT
164 return -EPERM;
165
166 /* required for strict SunOS emulation */
167 if (O_NONBLOCK != O_NDELAY)
168 if (arg & O_NDELAY)
169 arg |= O_NONBLOCK;
170
171 if (arg & O_DIRECT) {
172 if (!filp->f_mapping || !filp->f_mapping->a_ops ||
173 !filp->f_mapping->a_ops->direct_IO)
174 return -EINVAL;
175 }
176
177 if (filp->f_op && filp->f_op->check_flags)
178 error = filp->f_op->check_flags(arg);
179 if (error)
180 return error;
181
218d11a8 182 /*
76398425 183 * ->fasync() is responsible for setting the FASYNC bit.
218d11a8 184 */
76398425
JC
185 if (((arg ^ filp->f_flags) & FASYNC) && filp->f_op &&
186 filp->f_op->fasync) {
187 error = filp->f_op->fasync(fd, filp, (arg & FASYNC) != 0);
188 if (error < 0)
189 goto out;
60aa4924
JC
190 if (error > 0)
191 error = 0;
1da177e4 192 }
db1dd4d3 193 spin_lock(&filp->f_lock);
1da177e4 194 filp->f_flags = (arg & SETFL_MASK) | (filp->f_flags & ~SETFL_MASK);
db1dd4d3 195 spin_unlock(&filp->f_lock);
76398425 196
1da177e4 197 out:
1da177e4
LT
198 return error;
199}
200
609d7fa9 201static void f_modown(struct file *filp, struct pid *pid, enum pid_type type,
2f38d70f 202 int force)
1da177e4 203{
80e1e823 204 write_lock_irq(&filp->f_owner.lock);
1da177e4 205 if (force || !filp->f_owner.pid) {
609d7fa9
EB
206 put_pid(filp->f_owner.pid);
207 filp->f_owner.pid = get_pid(pid);
208 filp->f_owner.pid_type = type;
2f38d70f
ON
209
210 if (pid) {
211 const struct cred *cred = current_cred();
212 filp->f_owner.uid = cred->uid;
213 filp->f_owner.euid = cred->euid;
214 }
1da177e4 215 }
80e1e823 216 write_unlock_irq(&filp->f_owner.lock);
1da177e4
LT
217}
218
609d7fa9
EB
219int __f_setown(struct file *filp, struct pid *pid, enum pid_type type,
220 int force)
1da177e4
LT
221{
222 int err;
2f38d70f 223
1da177e4
LT
224 err = security_file_set_fowner(filp);
225 if (err)
226 return err;
227
2f38d70f 228 f_modown(filp, pid, type, force);
1da177e4
LT
229 return 0;
230}
609d7fa9 231EXPORT_SYMBOL(__f_setown);
1da177e4 232
609d7fa9
EB
233int f_setown(struct file *filp, unsigned long arg, int force)
234{
235 enum pid_type type;
236 struct pid *pid;
237 int who = arg;
238 int result;
239 type = PIDTYPE_PID;
240 if (who < 0) {
241 type = PIDTYPE_PGID;
242 who = -who;
243 }
244 rcu_read_lock();
b488893a 245 pid = find_vpid(who);
609d7fa9
EB
246 result = __f_setown(filp, pid, type, force);
247 rcu_read_unlock();
248 return result;
249}
1da177e4
LT
250EXPORT_SYMBOL(f_setown);
251
252void f_delown(struct file *filp)
253{
2f38d70f 254 f_modown(filp, NULL, PIDTYPE_PID, 1);
609d7fa9
EB
255}
256
257pid_t f_getown(struct file *filp)
258{
259 pid_t pid;
43fa1adb 260 read_lock(&filp->f_owner.lock);
6c5f3e7b 261 pid = pid_vnr(filp->f_owner.pid);
609d7fa9
EB
262 if (filp->f_owner.pid_type == PIDTYPE_PGID)
263 pid = -pid;
43fa1adb 264 read_unlock(&filp->f_owner.lock);
609d7fa9 265 return pid;
1da177e4
LT
266}
267
ba0a6c9f
PZ
268static int f_setown_ex(struct file *filp, unsigned long arg)
269{
270 struct f_owner_ex * __user owner_p = (void * __user)arg;
271 struct f_owner_ex owner;
272 struct pid *pid;
273 int type;
274 int ret;
275
276 ret = copy_from_user(&owner, owner_p, sizeof(owner));
277 if (ret)
5b54470d 278 return -EFAULT;
ba0a6c9f
PZ
279
280 switch (owner.type) {
281 case F_OWNER_TID:
282 type = PIDTYPE_MAX;
283 break;
284
285 case F_OWNER_PID:
286 type = PIDTYPE_PID;
287 break;
288
978b4053 289 case F_OWNER_PGRP:
ba0a6c9f
PZ
290 type = PIDTYPE_PGID;
291 break;
292
293 default:
294 return -EINVAL;
295 }
296
297 rcu_read_lock();
298 pid = find_vpid(owner.pid);
299 if (owner.pid && !pid)
300 ret = -ESRCH;
301 else
302 ret = __f_setown(filp, pid, type, 1);
303 rcu_read_unlock();
304
305 return ret;
306}
307
308static int f_getown_ex(struct file *filp, unsigned long arg)
309{
310 struct f_owner_ex * __user owner_p = (void * __user)arg;
311 struct f_owner_ex owner;
312 int ret = 0;
313
314 read_lock(&filp->f_owner.lock);
315 owner.pid = pid_vnr(filp->f_owner.pid);
316 switch (filp->f_owner.pid_type) {
317 case PIDTYPE_MAX:
318 owner.type = F_OWNER_TID;
319 break;
320
321 case PIDTYPE_PID:
322 owner.type = F_OWNER_PID;
323 break;
324
325 case PIDTYPE_PGID:
978b4053 326 owner.type = F_OWNER_PGRP;
ba0a6c9f
PZ
327 break;
328
329 default:
330 WARN_ON(1);
331 ret = -EINVAL;
332 break;
333 }
334 read_unlock(&filp->f_owner.lock);
335
5b54470d 336 if (!ret) {
ba0a6c9f 337 ret = copy_to_user(owner_p, &owner, sizeof(owner));
5b54470d
DC
338 if (ret)
339 ret = -EFAULT;
340 }
ba0a6c9f
PZ
341 return ret;
342}
343
1d151c33
CG
344#ifdef CONFIG_CHECKPOINT_RESTORE
345static int f_getowner_uids(struct file *filp, unsigned long arg)
346{
347 struct user_namespace *user_ns = current_user_ns();
348 uid_t * __user dst = (void * __user)arg;
349 uid_t src[2];
350 int err;
351
352 read_lock(&filp->f_owner.lock);
353 src[0] = from_kuid(user_ns, filp->f_owner.uid);
354 src[1] = from_kuid(user_ns, filp->f_owner.euid);
355 read_unlock(&filp->f_owner.lock);
356
357 err = put_user(src[0], &dst[0]);
358 err |= put_user(src[1], &dst[1]);
359
360 return err;
361}
362#else
363static int f_getowner_uids(struct file *filp, unsigned long arg)
364{
365 return -EINVAL;
366}
367#endif
368
1da177e4
LT
369static long do_fcntl(int fd, unsigned int cmd, unsigned long arg,
370 struct file *filp)
371{
372 long err = -EINVAL;
373
374 switch (cmd) {
375 case F_DUPFD:
22d2b35b 376 case F_DUPFD_CLOEXEC:
d554ed89 377 if (arg >= rlimit(RLIMIT_NOFILE))
4e1e018e 378 break;
1027abe8
AV
379 err = alloc_fd(arg, cmd == F_DUPFD_CLOEXEC ? O_CLOEXEC : 0);
380 if (err >= 0) {
381 get_file(filp);
382 fd_install(err, filp);
383 }
1da177e4
LT
384 break;
385 case F_GETFD:
386 err = get_close_on_exec(fd) ? FD_CLOEXEC : 0;
387 break;
388 case F_SETFD:
389 err = 0;
390 set_close_on_exec(fd, arg & FD_CLOEXEC);
391 break;
392 case F_GETFL:
393 err = filp->f_flags;
394 break;
395 case F_SETFL:
396 err = setfl(fd, filp, arg);
397 break;
398 case F_GETLK:
399 err = fcntl_getlk(filp, (struct flock __user *) arg);
400 break;
401 case F_SETLK:
402 case F_SETLKW:
c293621b 403 err = fcntl_setlk(fd, filp, cmd, (struct flock __user *) arg);
1da177e4
LT
404 break;
405 case F_GETOWN:
406 /*
407 * XXX If f_owner is a process group, the
408 * negative return value will get converted
409 * into an error. Oops. If we keep the
410 * current syscall conventions, the only way
411 * to fix this will be in libc.
412 */
609d7fa9 413 err = f_getown(filp);
1da177e4
LT
414 force_successful_syscall_return();
415 break;
416 case F_SETOWN:
417 err = f_setown(filp, arg, 1);
418 break;
ba0a6c9f
PZ
419 case F_GETOWN_EX:
420 err = f_getown_ex(filp, arg);
421 break;
422 case F_SETOWN_EX:
423 err = f_setown_ex(filp, arg);
424 break;
1d151c33
CG
425 case F_GETOWNER_UIDS:
426 err = f_getowner_uids(filp, arg);
427 break;
1da177e4
LT
428 case F_GETSIG:
429 err = filp->f_owner.signum;
430 break;
431 case F_SETSIG:
432 /* arg == 0 restores default behaviour. */
7ed20e1a 433 if (!valid_signal(arg)) {
1da177e4
LT
434 break;
435 }
436 err = 0;
437 filp->f_owner.signum = arg;
438 break;
439 case F_GETLEASE:
440 err = fcntl_getlease(filp);
441 break;
442 case F_SETLEASE:
443 err = fcntl_setlease(fd, filp, arg);
444 break;
445 case F_NOTIFY:
446 err = fcntl_dirnotify(fd, filp, arg);
447 break;
35f3d14d
JA
448 case F_SETPIPE_SZ:
449 case F_GETPIPE_SZ:
450 err = pipe_fcntl(filp, cmd, arg);
451 break;
1da177e4
LT
452 default:
453 break;
454 }
455 return err;
456}
457
1abf0c71
AV
458static int check_fcntl_cmd(unsigned cmd)
459{
460 switch (cmd) {
461 case F_DUPFD:
462 case F_DUPFD_CLOEXEC:
463 case F_GETFD:
464 case F_SETFD:
465 case F_GETFL:
466 return 1;
467 }
468 return 0;
469}
470
a26eab24 471SYSCALL_DEFINE3(fcntl, unsigned int, fd, unsigned int, cmd, unsigned long, arg)
1da177e4
LT
472{
473 struct file *filp;
545ec2c7 474 int fput_needed;
1da177e4
LT
475 long err = -EBADF;
476
545ec2c7 477 filp = fget_raw_light(fd, &fput_needed);
1da177e4
LT
478 if (!filp)
479 goto out;
480
1abf0c71 481 if (unlikely(filp->f_mode & FMODE_PATH)) {
545ec2c7
AV
482 if (!check_fcntl_cmd(cmd))
483 goto out1;
1abf0c71
AV
484 }
485
1da177e4 486 err = security_file_fcntl(filp, cmd, arg);
545ec2c7
AV
487 if (!err)
488 err = do_fcntl(fd, cmd, arg, filp);
1da177e4 489
545ec2c7
AV
490out1:
491 fput_light(filp, fput_needed);
1da177e4
LT
492out:
493 return err;
494}
495
496#if BITS_PER_LONG == 32
a26eab24
HC
497SYSCALL_DEFINE3(fcntl64, unsigned int, fd, unsigned int, cmd,
498 unsigned long, arg)
1da177e4
LT
499{
500 struct file * filp;
545ec2c7
AV
501 long err = -EBADF;
502 int fput_needed;
1da177e4 503
545ec2c7 504 filp = fget_raw_light(fd, &fput_needed);
1da177e4
LT
505 if (!filp)
506 goto out;
507
1abf0c71 508 if (unlikely(filp->f_mode & FMODE_PATH)) {
545ec2c7
AV
509 if (!check_fcntl_cmd(cmd))
510 goto out1;
1abf0c71
AV
511 }
512
1da177e4 513 err = security_file_fcntl(filp, cmd, arg);
545ec2c7
AV
514 if (err)
515 goto out1;
1da177e4
LT
516
517 switch (cmd) {
518 case F_GETLK64:
519 err = fcntl_getlk64(filp, (struct flock64 __user *) arg);
520 break;
521 case F_SETLK64:
522 case F_SETLKW64:
c293621b
PS
523 err = fcntl_setlk64(fd, filp, cmd,
524 (struct flock64 __user *) arg);
1da177e4
LT
525 break;
526 default:
527 err = do_fcntl(fd, cmd, arg, filp);
528 break;
529 }
545ec2c7
AV
530out1:
531 fput_light(filp, fput_needed);
1da177e4
LT
532out:
533 return err;
534}
535#endif
536
537/* Table to convert sigio signal codes into poll band bitmaps */
538
fa3536cc 539static const long band_table[NSIGPOLL] = {
1da177e4
LT
540 POLLIN | POLLRDNORM, /* POLL_IN */
541 POLLOUT | POLLWRNORM | POLLWRBAND, /* POLL_OUT */
542 POLLIN | POLLRDNORM | POLLMSG, /* POLL_MSG */
543 POLLERR, /* POLL_ERR */
544 POLLPRI | POLLRDBAND, /* POLL_PRI */
545 POLLHUP | POLLERR /* POLL_HUP */
546};
547
548static inline int sigio_perm(struct task_struct *p,
549 struct fown_struct *fown, int sig)
550{
c69e8d9c
DH
551 const struct cred *cred;
552 int ret;
553
554 rcu_read_lock();
555 cred = __task_cred(p);
8e96e3b7
EB
556 ret = ((uid_eq(fown->euid, GLOBAL_ROOT_UID) ||
557 uid_eq(fown->euid, cred->suid) || uid_eq(fown->euid, cred->uid) ||
558 uid_eq(fown->uid, cred->suid) || uid_eq(fown->uid, cred->uid)) &&
c69e8d9c
DH
559 !security_file_send_sigiotask(p, fown, sig));
560 rcu_read_unlock();
561 return ret;
1da177e4
LT
562}
563
564static void send_sigio_to_task(struct task_struct *p,
8eeee4e2 565 struct fown_struct *fown,
ba0a6c9f 566 int fd, int reason, int group)
1da177e4 567{
8eeee4e2
ON
568 /*
569 * F_SETSIG can change ->signum lockless in parallel, make
570 * sure we read it once and use the same value throughout.
571 */
572 int signum = ACCESS_ONCE(fown->signum);
573
574 if (!sigio_perm(p, fown, signum))
1da177e4
LT
575 return;
576
8eeee4e2 577 switch (signum) {
1da177e4
LT
578 siginfo_t si;
579 default:
580 /* Queue a rt signal with the appropriate fd as its
581 value. We use SI_SIGIO as the source, not
582 SI_KERNEL, since kernel signals always get
583 delivered even if we can't queue. Failure to
584 queue in this case _should_ be reported; we fall
585 back to SIGIO in that case. --sct */
8eeee4e2 586 si.si_signo = signum;
1da177e4
LT
587 si.si_errno = 0;
588 si.si_code = reason;
589 /* Make sure we are called with one of the POLL_*
590 reasons, otherwise we could leak kernel stack into
591 userspace. */
f6298aab 592 BUG_ON((reason & __SI_MASK) != __SI_POLL);
1da177e4
LT
593 if (reason - POLL_IN >= NSIGPOLL)
594 si.si_band = ~0L;
595 else
596 si.si_band = band_table[reason - POLL_IN];
597 si.si_fd = fd;
ba0a6c9f 598 if (!do_send_sig_info(signum, &si, p, group))
1da177e4
LT
599 break;
600 /* fall-through: fall back on the old plain SIGIO signal */
601 case 0:
ba0a6c9f 602 do_send_sig_info(SIGIO, SEND_SIG_PRIV, p, group);
1da177e4
LT
603 }
604}
605
606void send_sigio(struct fown_struct *fown, int fd, int band)
607{
608 struct task_struct *p;
609d7fa9
EB
609 enum pid_type type;
610 struct pid *pid;
ba0a6c9f 611 int group = 1;
1da177e4
LT
612
613 read_lock(&fown->lock);
ba0a6c9f 614
609d7fa9 615 type = fown->pid_type;
ba0a6c9f
PZ
616 if (type == PIDTYPE_MAX) {
617 group = 0;
618 type = PIDTYPE_PID;
619 }
620
1da177e4
LT
621 pid = fown->pid;
622 if (!pid)
623 goto out_unlock_fown;
624
625 read_lock(&tasklist_lock);
609d7fa9 626 do_each_pid_task(pid, type, p) {
ba0a6c9f 627 send_sigio_to_task(p, fown, fd, band, group);
609d7fa9 628 } while_each_pid_task(pid, type, p);
1da177e4
LT
629 read_unlock(&tasklist_lock);
630 out_unlock_fown:
631 read_unlock(&fown->lock);
632}
633
634static void send_sigurg_to_task(struct task_struct *p,
ba0a6c9f 635 struct fown_struct *fown, int group)
1da177e4
LT
636{
637 if (sigio_perm(p, fown, SIGURG))
ba0a6c9f 638 do_send_sig_info(SIGURG, SEND_SIG_PRIV, p, group);
1da177e4
LT
639}
640
641int send_sigurg(struct fown_struct *fown)
642{
643 struct task_struct *p;
609d7fa9
EB
644 enum pid_type type;
645 struct pid *pid;
ba0a6c9f 646 int group = 1;
609d7fa9 647 int ret = 0;
1da177e4
LT
648
649 read_lock(&fown->lock);
ba0a6c9f 650
609d7fa9 651 type = fown->pid_type;
ba0a6c9f
PZ
652 if (type == PIDTYPE_MAX) {
653 group = 0;
654 type = PIDTYPE_PID;
655 }
656
1da177e4
LT
657 pid = fown->pid;
658 if (!pid)
659 goto out_unlock_fown;
660
661 ret = 1;
662
663 read_lock(&tasklist_lock);
609d7fa9 664 do_each_pid_task(pid, type, p) {
ba0a6c9f 665 send_sigurg_to_task(p, fown, group);
609d7fa9 666 } while_each_pid_task(pid, type, p);
1da177e4
LT
667 read_unlock(&tasklist_lock);
668 out_unlock_fown:
669 read_unlock(&fown->lock);
670 return ret;
671}
672
989a2979 673static DEFINE_SPINLOCK(fasync_lock);
e18b890b 674static struct kmem_cache *fasync_cache __read_mostly;
1da177e4 675
989a2979
ED
676static void fasync_free_rcu(struct rcu_head *head)
677{
678 kmem_cache_free(fasync_cache,
679 container_of(head, struct fasync_struct, fa_rcu));
680}
681
1da177e4 682/*
53281b6d
LT
683 * Remove a fasync entry. If successfully removed, return
684 * positive and clear the FASYNC flag. If no entry exists,
685 * do nothing and return 0.
686 *
687 * NOTE! It is very important that the FASYNC flag always
688 * match the state "is the filp on a fasync list".
689 *
1da177e4 690 */
f7347ce4 691int fasync_remove_entry(struct file *filp, struct fasync_struct **fapp)
1da177e4
LT
692{
693 struct fasync_struct *fa, **fp;
1da177e4
LT
694 int result = 0;
695
53281b6d 696 spin_lock(&filp->f_lock);
989a2979 697 spin_lock(&fasync_lock);
53281b6d
LT
698 for (fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) {
699 if (fa->fa_file != filp)
700 continue;
989a2979
ED
701
702 spin_lock_irq(&fa->fa_lock);
703 fa->fa_file = NULL;
704 spin_unlock_irq(&fa->fa_lock);
705
53281b6d 706 *fp = fa->fa_next;
989a2979 707 call_rcu(&fa->fa_rcu, fasync_free_rcu);
53281b6d
LT
708 filp->f_flags &= ~FASYNC;
709 result = 1;
710 break;
1da177e4 711 }
989a2979 712 spin_unlock(&fasync_lock);
53281b6d
LT
713 spin_unlock(&filp->f_lock);
714 return result;
715}
716
f7347ce4
LT
717struct fasync_struct *fasync_alloc(void)
718{
719 return kmem_cache_alloc(fasync_cache, GFP_KERNEL);
720}
721
53281b6d 722/*
f7347ce4
LT
723 * NOTE! This can be used only for unused fasync entries:
724 * entries that actually got inserted on the fasync list
725 * need to be released by rcu - see fasync_remove_entry.
53281b6d 726 */
f7347ce4 727void fasync_free(struct fasync_struct *new)
53281b6d 728{
f7347ce4
LT
729 kmem_cache_free(fasync_cache, new);
730}
53281b6d 731
f7347ce4
LT
732/*
733 * Insert a new entry into the fasync list. Return the pointer to the
734 * old one if we didn't use the new one.
55f335a8
LT
735 *
736 * NOTE! It is very important that the FASYNC flag always
737 * match the state "is the filp on a fasync list".
f7347ce4
LT
738 */
739struct fasync_struct *fasync_insert_entry(int fd, struct file *filp, struct fasync_struct **fapp, struct fasync_struct *new)
740{
741 struct fasync_struct *fa, **fp;
4a6a4499 742
4a6a4499 743 spin_lock(&filp->f_lock);
989a2979 744 spin_lock(&fasync_lock);
1da177e4 745 for (fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) {
53281b6d
LT
746 if (fa->fa_file != filp)
747 continue;
989a2979
ED
748
749 spin_lock_irq(&fa->fa_lock);
53281b6d 750 fa->fa_fd = fd;
989a2979 751 spin_unlock_irq(&fa->fa_lock);
53281b6d 752 goto out;
1da177e4
LT
753 }
754
989a2979 755 spin_lock_init(&new->fa_lock);
53281b6d
LT
756 new->magic = FASYNC_MAGIC;
757 new->fa_file = filp;
758 new->fa_fd = fd;
759 new->fa_next = *fapp;
989a2979 760 rcu_assign_pointer(*fapp, new);
53281b6d
LT
761 filp->f_flags |= FASYNC;
762
1da177e4 763out:
989a2979 764 spin_unlock(&fasync_lock);
4a6a4499 765 spin_unlock(&filp->f_lock);
f7347ce4
LT
766 return fa;
767}
768
769/*
770 * Add a fasync entry. Return negative on error, positive if
771 * added, and zero if did nothing but change an existing one.
f7347ce4
LT
772 */
773static int fasync_add_entry(int fd, struct file *filp, struct fasync_struct **fapp)
774{
775 struct fasync_struct *new;
776
777 new = fasync_alloc();
778 if (!new)
779 return -ENOMEM;
780
781 /*
782 * fasync_insert_entry() returns the old (update) entry if
783 * it existed.
784 *
785 * So free the (unused) new entry and return 0 to let the
786 * caller know that we didn't add any new fasync entries.
787 */
788 if (fasync_insert_entry(fd, filp, fapp, new)) {
789 fasync_free(new);
790 return 0;
791 }
792
793 return 1;
1da177e4
LT
794}
795
53281b6d
LT
796/*
797 * fasync_helper() is used by almost all character device drivers
798 * to set up the fasync queue, and for regular files by the file
799 * lease code. It returns negative on error, 0 if it did no changes
800 * and positive if it added/deleted the entry.
801 */
802int fasync_helper(int fd, struct file * filp, int on, struct fasync_struct **fapp)
803{
804 if (!on)
805 return fasync_remove_entry(filp, fapp);
806 return fasync_add_entry(fd, filp, fapp);
807}
808
1da177e4
LT
809EXPORT_SYMBOL(fasync_helper);
810
989a2979
ED
811/*
812 * rcu_read_lock() is held
813 */
814static void kill_fasync_rcu(struct fasync_struct *fa, int sig, int band)
1da177e4
LT
815{
816 while (fa) {
989a2979 817 struct fown_struct *fown;
f4985dc7
AM
818 unsigned long flags;
819
1da177e4
LT
820 if (fa->magic != FASYNC_MAGIC) {
821 printk(KERN_ERR "kill_fasync: bad magic number in "
822 "fasync_struct!\n");
823 return;
824 }
f4985dc7 825 spin_lock_irqsave(&fa->fa_lock, flags);
989a2979
ED
826 if (fa->fa_file) {
827 fown = &fa->fa_file->f_owner;
828 /* Don't send SIGURG to processes which have not set a
829 queued signum: SIGURG has its own default signalling
830 mechanism. */
831 if (!(sig == SIGURG && fown->signum == 0))
832 send_sigio(fown, fa->fa_fd, band);
833 }
f4985dc7 834 spin_unlock_irqrestore(&fa->fa_lock, flags);
989a2979 835 fa = rcu_dereference(fa->fa_next);
1da177e4
LT
836 }
837}
838
1da177e4
LT
839void kill_fasync(struct fasync_struct **fp, int sig, int band)
840{
841 /* First a quick test without locking: usually
842 * the list is empty.
843 */
844 if (*fp) {
989a2979
ED
845 rcu_read_lock();
846 kill_fasync_rcu(rcu_dereference(*fp), sig, band);
847 rcu_read_unlock();
1da177e4
LT
848 }
849}
850EXPORT_SYMBOL(kill_fasync);
851
454eedb8 852static int __init fcntl_init(void)
1da177e4 853{
3ab04d5c
JB
854 /*
855 * Please add new bits here to ensure allocation uniqueness.
856 * Exceptions: O_NONBLOCK is a two bit define on parisc; O_NDELAY
857 * is defined as O_NONBLOCK on some platforms and not on others.
858 */
1abf0c71 859 BUILD_BUG_ON(19 - 1 /* for O_RDONLY being 0 */ != HWEIGHT32(
454eedb8
WF
860 O_RDONLY | O_WRONLY | O_RDWR |
861 O_CREAT | O_EXCL | O_NOCTTY |
3ab04d5c 862 O_TRUNC | O_APPEND | /* O_NONBLOCK | */
454eedb8
WF
863 __O_SYNC | O_DSYNC | FASYNC |
864 O_DIRECT | O_LARGEFILE | O_DIRECTORY |
865 O_NOFOLLOW | O_NOATIME | O_CLOEXEC |
1abf0c71 866 __FMODE_EXEC | O_PATH
454eedb8
WF
867 ));
868
1da177e4 869 fasync_cache = kmem_cache_create("fasync_cache",
20c2df83 870 sizeof(struct fasync_struct), 0, SLAB_PANIC, NULL);
1da177e4
LT
871 return 0;
872}
873
454eedb8 874module_init(fcntl_init)