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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * linux/fs/fcntl.c
4 *
5 * Copyright (C) 1991, 1992 Linus Torvalds
6 */
7
8#include <linux/syscalls.h>
9#include <linux/init.h>
10#include <linux/mm.h>
11#include <linux/sched/task.h>
12#include <linux/fs.h>
13#include <linux/file.h>
14#include <linux/fdtable.h>
15#include <linux/capability.h>
16#include <linux/dnotify.h>
17#include <linux/slab.h>
18#include <linux/module.h>
19#include <linux/pipe_fs_i.h>
20#include <linux/security.h>
21#include <linux/ptrace.h>
22#include <linux/signal.h>
23#include <linux/rcupdate.h>
24#include <linux/pid_namespace.h>
25#include <linux/user_namespace.h>
26#include <linux/memfd.h>
27#include <linux/compat.h>
28
29#include <linux/poll.h>
30#include <asm/siginfo.h>
31#include <linux/uaccess.h>
32
33#define SETFL_MASK (O_APPEND | O_NONBLOCK | O_NDELAY | O_DIRECT | O_NOATIME)
34
35static int setfl(int fd, struct file * filp, unsigned long arg)
36{
37 struct inode * inode = file_inode(filp);
38 int error = 0;
39
40 /*
41 * O_APPEND cannot be cleared if the file is marked as append-only
42 * and the file is open for write.
43 */
44 if (((arg ^ filp->f_flags) & O_APPEND) && IS_APPEND(inode))
45 return -EPERM;
46
47 /* O_NOATIME can only be set by the owner or superuser */
48 if ((arg & O_NOATIME) && !(filp->f_flags & O_NOATIME))
49 if (!inode_owner_or_capable(inode))
50 return -EPERM;
51
52 /* required for strict SunOS emulation */
53 if (O_NONBLOCK != O_NDELAY)
54 if (arg & O_NDELAY)
55 arg |= O_NONBLOCK;
56
57 /* Pipe packetized mode is controlled by O_DIRECT flag */
58 if (!S_ISFIFO(inode->i_mode) && (arg & O_DIRECT)) {
59 if (!filp->f_mapping || !filp->f_mapping->a_ops ||
60 !filp->f_mapping->a_ops->direct_IO)
61 return -EINVAL;
62 }
63
64 if (filp->f_op->check_flags)
65 error = filp->f_op->check_flags(arg);
66 if (error)
67 return error;
68
69 /*
70 * ->fasync() is responsible for setting the FASYNC bit.
71 */
72 if (((arg ^ filp->f_flags) & FASYNC) && filp->f_op->fasync) {
73 error = filp->f_op->fasync(fd, filp, (arg & FASYNC) != 0);
74 if (error < 0)
75 goto out;
76 if (error > 0)
77 error = 0;
78 }
79 spin_lock(&filp->f_lock);
80 filp->f_flags = (arg & SETFL_MASK) | (filp->f_flags & ~SETFL_MASK);
81 spin_unlock(&filp->f_lock);
82
83 out:
84 return error;
85}
86
87static void f_modown(struct file *filp, struct pid *pid, enum pid_type type,
88 int force)
89{
90 write_lock_irq(&filp->f_owner.lock);
91 if (force || !filp->f_owner.pid) {
92 put_pid(filp->f_owner.pid);
93 filp->f_owner.pid = get_pid(pid);
94 filp->f_owner.pid_type = type;
95
96 if (pid) {
97 const struct cred *cred = current_cred();
98 filp->f_owner.uid = cred->uid;
99 filp->f_owner.euid = cred->euid;
100 }
101 }
102 write_unlock_irq(&filp->f_owner.lock);
103}
104
105void __f_setown(struct file *filp, struct pid *pid, enum pid_type type,
106 int force)
107{
108 security_file_set_fowner(filp);
109 f_modown(filp, pid, type, force);
110}
111EXPORT_SYMBOL(__f_setown);
112
113int f_setown(struct file *filp, unsigned long arg, int force)
114{
115 enum pid_type type;
116 struct pid *pid = NULL;
117 int who = arg, ret = 0;
118
119 type = PIDTYPE_TGID;
120 if (who < 0) {
121 /* avoid overflow below */
122 if (who == INT_MIN)
123 return -EINVAL;
124
125 type = PIDTYPE_PGID;
126 who = -who;
127 }
128
129 rcu_read_lock();
130 if (who) {
131 pid = find_vpid(who);
132 if (!pid)
133 ret = -ESRCH;
134 }
135
136 if (!ret)
137 __f_setown(filp, pid, type, force);
138 rcu_read_unlock();
139
140 return ret;
141}
142EXPORT_SYMBOL(f_setown);
143
144void f_delown(struct file *filp)
145{
146 f_modown(filp, NULL, PIDTYPE_TGID, 1);
147}
148
149pid_t f_getown(struct file *filp)
150{
151 pid_t pid;
152 read_lock(&filp->f_owner.lock);
153 pid = pid_vnr(filp->f_owner.pid);
154 if (filp->f_owner.pid_type == PIDTYPE_PGID)
155 pid = -pid;
156 read_unlock(&filp->f_owner.lock);
157 return pid;
158}
159
160static int f_setown_ex(struct file *filp, unsigned long arg)
161{
162 struct f_owner_ex __user *owner_p = (void __user *)arg;
163 struct f_owner_ex owner;
164 struct pid *pid;
165 int type;
166 int ret;
167
168 ret = copy_from_user(&owner, owner_p, sizeof(owner));
169 if (ret)
170 return -EFAULT;
171
172 switch (owner.type) {
173 case F_OWNER_TID:
174 type = PIDTYPE_PID;
175 break;
176
177 case F_OWNER_PID:
178 type = PIDTYPE_TGID;
179 break;
180
181 case F_OWNER_PGRP:
182 type = PIDTYPE_PGID;
183 break;
184
185 default:
186 return -EINVAL;
187 }
188
189 rcu_read_lock();
190 pid = find_vpid(owner.pid);
191 if (owner.pid && !pid)
192 ret = -ESRCH;
193 else
194 __f_setown(filp, pid, type, 1);
195 rcu_read_unlock();
196
197 return ret;
198}
199
200static int f_getown_ex(struct file *filp, unsigned long arg)
201{
202 struct f_owner_ex __user *owner_p = (void __user *)arg;
203 struct f_owner_ex owner;
204 int ret = 0;
205
206 read_lock(&filp->f_owner.lock);
207 owner.pid = pid_vnr(filp->f_owner.pid);
208 switch (filp->f_owner.pid_type) {
209 case PIDTYPE_PID:
210 owner.type = F_OWNER_TID;
211 break;
212
213 case PIDTYPE_TGID:
214 owner.type = F_OWNER_PID;
215 break;
216
217 case PIDTYPE_PGID:
218 owner.type = F_OWNER_PGRP;
219 break;
220
221 default:
222 WARN_ON(1);
223 ret = -EINVAL;
224 break;
225 }
226 read_unlock(&filp->f_owner.lock);
227
228 if (!ret) {
229 ret = copy_to_user(owner_p, &owner, sizeof(owner));
230 if (ret)
231 ret = -EFAULT;
232 }
233 return ret;
234}
235
236#ifdef CONFIG_CHECKPOINT_RESTORE
237static int f_getowner_uids(struct file *filp, unsigned long arg)
238{
239 struct user_namespace *user_ns = current_user_ns();
240 uid_t __user *dst = (void __user *)arg;
241 uid_t src[2];
242 int err;
243
244 read_lock(&filp->f_owner.lock);
245 src[0] = from_kuid(user_ns, filp->f_owner.uid);
246 src[1] = from_kuid(user_ns, filp->f_owner.euid);
247 read_unlock(&filp->f_owner.lock);
248
249 err = put_user(src[0], &dst[0]);
250 err |= put_user(src[1], &dst[1]);
251
252 return err;
253}
254#else
255static int f_getowner_uids(struct file *filp, unsigned long arg)
256{
257 return -EINVAL;
258}
259#endif
260
261static bool rw_hint_valid(enum rw_hint hint)
262{
263 switch (hint) {
264 case RWH_WRITE_LIFE_NOT_SET:
265 case RWH_WRITE_LIFE_NONE:
266 case RWH_WRITE_LIFE_SHORT:
267 case RWH_WRITE_LIFE_MEDIUM:
268 case RWH_WRITE_LIFE_LONG:
269 case RWH_WRITE_LIFE_EXTREME:
270 return true;
271 default:
272 return false;
273 }
274}
275
276static long fcntl_rw_hint(struct file *file, unsigned int cmd,
277 unsigned long arg)
278{
279 struct inode *inode = file_inode(file);
280 u64 __user *argp = (u64 __user *)arg;
281 enum rw_hint hint;
282 u64 h;
283
284 switch (cmd) {
285 case F_GET_FILE_RW_HINT:
286 h = file_write_hint(file);
287 if (copy_to_user(argp, &h, sizeof(*argp)))
288 return -EFAULT;
289 return 0;
290 case F_SET_FILE_RW_HINT:
291 if (copy_from_user(&h, argp, sizeof(h)))
292 return -EFAULT;
293 hint = (enum rw_hint) h;
294 if (!rw_hint_valid(hint))
295 return -EINVAL;
296
297 spin_lock(&file->f_lock);
298 file->f_write_hint = hint;
299 spin_unlock(&file->f_lock);
300 return 0;
301 case F_GET_RW_HINT:
302 h = inode->i_write_hint;
303 if (copy_to_user(argp, &h, sizeof(*argp)))
304 return -EFAULT;
305 return 0;
306 case F_SET_RW_HINT:
307 if (copy_from_user(&h, argp, sizeof(h)))
308 return -EFAULT;
309 hint = (enum rw_hint) h;
310 if (!rw_hint_valid(hint))
311 return -EINVAL;
312
313 inode_lock(inode);
314 inode->i_write_hint = hint;
315 inode_unlock(inode);
316 return 0;
317 default:
318 return -EINVAL;
319 }
320}
321
322static long do_fcntl(int fd, unsigned int cmd, unsigned long arg,
323 struct file *filp)
324{
325 void __user *argp = (void __user *)arg;
326 struct flock flock;
327 long err = -EINVAL;
328
329 switch (cmd) {
330 case F_DUPFD:
331 err = f_dupfd(arg, filp, 0);
332 break;
333 case F_DUPFD_CLOEXEC:
334 err = f_dupfd(arg, filp, O_CLOEXEC);
335 break;
336 case F_GETFD:
337 err = get_close_on_exec(fd) ? FD_CLOEXEC : 0;
338 break;
339 case F_SETFD:
340 err = 0;
341 set_close_on_exec(fd, arg & FD_CLOEXEC);
342 break;
343 case F_GETFL:
344 err = filp->f_flags;
345 break;
346 case F_SETFL:
347 err = setfl(fd, filp, arg);
348 break;
349#if BITS_PER_LONG != 32
350 /* 32-bit arches must use fcntl64() */
351 case F_OFD_GETLK:
352#endif
353 case F_GETLK:
354 if (copy_from_user(&flock, argp, sizeof(flock)))
355 return -EFAULT;
356 err = fcntl_getlk(filp, cmd, &flock);
357 if (!err && copy_to_user(argp, &flock, sizeof(flock)))
358 return -EFAULT;
359 break;
360#if BITS_PER_LONG != 32
361 /* 32-bit arches must use fcntl64() */
362 case F_OFD_SETLK:
363 case F_OFD_SETLKW:
364#endif
365 fallthrough;
366 case F_SETLK:
367 case F_SETLKW:
368 if (copy_from_user(&flock, argp, sizeof(flock)))
369 return -EFAULT;
370 err = fcntl_setlk(fd, filp, cmd, &flock);
371 break;
372 case F_GETOWN:
373 /*
374 * XXX If f_owner is a process group, the
375 * negative return value will get converted
376 * into an error. Oops. If we keep the
377 * current syscall conventions, the only way
378 * to fix this will be in libc.
379 */
380 err = f_getown(filp);
381 force_successful_syscall_return();
382 break;
383 case F_SETOWN:
384 err = f_setown(filp, arg, 1);
385 break;
386 case F_GETOWN_EX:
387 err = f_getown_ex(filp, arg);
388 break;
389 case F_SETOWN_EX:
390 err = f_setown_ex(filp, arg);
391 break;
392 case F_GETOWNER_UIDS:
393 err = f_getowner_uids(filp, arg);
394 break;
395 case F_GETSIG:
396 err = filp->f_owner.signum;
397 break;
398 case F_SETSIG:
399 /* arg == 0 restores default behaviour. */
400 if (!valid_signal(arg)) {
401 break;
402 }
403 err = 0;
404 filp->f_owner.signum = arg;
405 break;
406 case F_GETLEASE:
407 err = fcntl_getlease(filp);
408 break;
409 case F_SETLEASE:
410 err = fcntl_setlease(fd, filp, arg);
411 break;
412 case F_NOTIFY:
413 err = fcntl_dirnotify(fd, filp, arg);
414 break;
415 case F_SETPIPE_SZ:
416 case F_GETPIPE_SZ:
417 err = pipe_fcntl(filp, cmd, arg);
418 break;
419 case F_ADD_SEALS:
420 case F_GET_SEALS:
421 err = memfd_fcntl(filp, cmd, arg);
422 break;
423 case F_GET_RW_HINT:
424 case F_SET_RW_HINT:
425 case F_GET_FILE_RW_HINT:
426 case F_SET_FILE_RW_HINT:
427 err = fcntl_rw_hint(filp, cmd, arg);
428 break;
429 default:
430 break;
431 }
432 return err;
433}
434
435static int check_fcntl_cmd(unsigned cmd)
436{
437 switch (cmd) {
438 case F_DUPFD:
439 case F_DUPFD_CLOEXEC:
440 case F_GETFD:
441 case F_SETFD:
442 case F_GETFL:
443 return 1;
444 }
445 return 0;
446}
447
448SYSCALL_DEFINE3(fcntl, unsigned int, fd, unsigned int, cmd, unsigned long, arg)
449{
450 struct fd f = fdget_raw(fd);
451 long err = -EBADF;
452
453 if (!f.file)
454 goto out;
455
456 if (unlikely(f.file->f_mode & FMODE_PATH)) {
457 if (!check_fcntl_cmd(cmd))
458 goto out1;
459 }
460
461 err = security_file_fcntl(f.file, cmd, arg);
462 if (!err)
463 err = do_fcntl(fd, cmd, arg, f.file);
464
465out1:
466 fdput(f);
467out:
468 return err;
469}
470
471#if BITS_PER_LONG == 32
472SYSCALL_DEFINE3(fcntl64, unsigned int, fd, unsigned int, cmd,
473 unsigned long, arg)
474{
475 void __user *argp = (void __user *)arg;
476 struct fd f = fdget_raw(fd);
477 struct flock64 flock;
478 long err = -EBADF;
479
480 if (!f.file)
481 goto out;
482
483 if (unlikely(f.file->f_mode & FMODE_PATH)) {
484 if (!check_fcntl_cmd(cmd))
485 goto out1;
486 }
487
488 err = security_file_fcntl(f.file, cmd, arg);
489 if (err)
490 goto out1;
491
492 switch (cmd) {
493 case F_GETLK64:
494 case F_OFD_GETLK:
495 err = -EFAULT;
496 if (copy_from_user(&flock, argp, sizeof(flock)))
497 break;
498 err = fcntl_getlk64(f.file, cmd, &flock);
499 if (!err && copy_to_user(argp, &flock, sizeof(flock)))
500 err = -EFAULT;
501 break;
502 case F_SETLK64:
503 case F_SETLKW64:
504 case F_OFD_SETLK:
505 case F_OFD_SETLKW:
506 err = -EFAULT;
507 if (copy_from_user(&flock, argp, sizeof(flock)))
508 break;
509 err = fcntl_setlk64(fd, f.file, cmd, &flock);
510 break;
511 default:
512 err = do_fcntl(fd, cmd, arg, f.file);
513 break;
514 }
515out1:
516 fdput(f);
517out:
518 return err;
519}
520#endif
521
522#ifdef CONFIG_COMPAT
523/* careful - don't use anywhere else */
524#define copy_flock_fields(dst, src) \
525 (dst)->l_type = (src)->l_type; \
526 (dst)->l_whence = (src)->l_whence; \
527 (dst)->l_start = (src)->l_start; \
528 (dst)->l_len = (src)->l_len; \
529 (dst)->l_pid = (src)->l_pid;
530
531static int get_compat_flock(struct flock *kfl, const struct compat_flock __user *ufl)
532{
533 struct compat_flock fl;
534
535 if (copy_from_user(&fl, ufl, sizeof(struct compat_flock)))
536 return -EFAULT;
537 copy_flock_fields(kfl, &fl);
538 return 0;
539}
540
541static int get_compat_flock64(struct flock *kfl, const struct compat_flock64 __user *ufl)
542{
543 struct compat_flock64 fl;
544
545 if (copy_from_user(&fl, ufl, sizeof(struct compat_flock64)))
546 return -EFAULT;
547 copy_flock_fields(kfl, &fl);
548 return 0;
549}
550
551static int put_compat_flock(const struct flock *kfl, struct compat_flock __user *ufl)
552{
553 struct compat_flock fl;
554
555 memset(&fl, 0, sizeof(struct compat_flock));
556 copy_flock_fields(&fl, kfl);
557 if (copy_to_user(ufl, &fl, sizeof(struct compat_flock)))
558 return -EFAULT;
559 return 0;
560}
561
562static int put_compat_flock64(const struct flock *kfl, struct compat_flock64 __user *ufl)
563{
564 struct compat_flock64 fl;
565
566 BUILD_BUG_ON(sizeof(kfl->l_start) > sizeof(ufl->l_start));
567 BUILD_BUG_ON(sizeof(kfl->l_len) > sizeof(ufl->l_len));
568
569 memset(&fl, 0, sizeof(struct compat_flock64));
570 copy_flock_fields(&fl, kfl);
571 if (copy_to_user(ufl, &fl, sizeof(struct compat_flock64)))
572 return -EFAULT;
573 return 0;
574}
575#undef copy_flock_fields
576
577static unsigned int
578convert_fcntl_cmd(unsigned int cmd)
579{
580 switch (cmd) {
581 case F_GETLK64:
582 return F_GETLK;
583 case F_SETLK64:
584 return F_SETLK;
585 case F_SETLKW64:
586 return F_SETLKW;
587 }
588
589 return cmd;
590}
591
592/*
593 * GETLK was successful and we need to return the data, but it needs to fit in
594 * the compat structure.
595 * l_start shouldn't be too big, unless the original start + end is greater than
596 * COMPAT_OFF_T_MAX, in which case the app was asking for trouble, so we return
597 * -EOVERFLOW in that case. l_len could be too big, in which case we just
598 * truncate it, and only allow the app to see that part of the conflicting lock
599 * that might make sense to it anyway
600 */
601static int fixup_compat_flock(struct flock *flock)
602{
603 if (flock->l_start > COMPAT_OFF_T_MAX)
604 return -EOVERFLOW;
605 if (flock->l_len > COMPAT_OFF_T_MAX)
606 flock->l_len = COMPAT_OFF_T_MAX;
607 return 0;
608}
609
610static long do_compat_fcntl64(unsigned int fd, unsigned int cmd,
611 compat_ulong_t arg)
612{
613 struct fd f = fdget_raw(fd);
614 struct flock flock;
615 long err = -EBADF;
616
617 if (!f.file)
618 return err;
619
620 if (unlikely(f.file->f_mode & FMODE_PATH)) {
621 if (!check_fcntl_cmd(cmd))
622 goto out_put;
623 }
624
625 err = security_file_fcntl(f.file, cmd, arg);
626 if (err)
627 goto out_put;
628
629 switch (cmd) {
630 case F_GETLK:
631 err = get_compat_flock(&flock, compat_ptr(arg));
632 if (err)
633 break;
634 err = fcntl_getlk(f.file, convert_fcntl_cmd(cmd), &flock);
635 if (err)
636 break;
637 err = fixup_compat_flock(&flock);
638 if (!err)
639 err = put_compat_flock(&flock, compat_ptr(arg));
640 break;
641 case F_GETLK64:
642 case F_OFD_GETLK:
643 err = get_compat_flock64(&flock, compat_ptr(arg));
644 if (err)
645 break;
646 err = fcntl_getlk(f.file, convert_fcntl_cmd(cmd), &flock);
647 if (!err)
648 err = put_compat_flock64(&flock, compat_ptr(arg));
649 break;
650 case F_SETLK:
651 case F_SETLKW:
652 err = get_compat_flock(&flock, compat_ptr(arg));
653 if (err)
654 break;
655 err = fcntl_setlk(fd, f.file, convert_fcntl_cmd(cmd), &flock);
656 break;
657 case F_SETLK64:
658 case F_SETLKW64:
659 case F_OFD_SETLK:
660 case F_OFD_SETLKW:
661 err = get_compat_flock64(&flock, compat_ptr(arg));
662 if (err)
663 break;
664 err = fcntl_setlk(fd, f.file, convert_fcntl_cmd(cmd), &flock);
665 break;
666 default:
667 err = do_fcntl(fd, cmd, arg, f.file);
668 break;
669 }
670out_put:
671 fdput(f);
672 return err;
673}
674
675COMPAT_SYSCALL_DEFINE3(fcntl64, unsigned int, fd, unsigned int, cmd,
676 compat_ulong_t, arg)
677{
678 return do_compat_fcntl64(fd, cmd, arg);
679}
680
681COMPAT_SYSCALL_DEFINE3(fcntl, unsigned int, fd, unsigned int, cmd,
682 compat_ulong_t, arg)
683{
684 switch (cmd) {
685 case F_GETLK64:
686 case F_SETLK64:
687 case F_SETLKW64:
688 case F_OFD_GETLK:
689 case F_OFD_SETLK:
690 case F_OFD_SETLKW:
691 return -EINVAL;
692 }
693 return do_compat_fcntl64(fd, cmd, arg);
694}
695#endif
696
697/* Table to convert sigio signal codes into poll band bitmaps */
698
699static const __poll_t band_table[NSIGPOLL] = {
700 EPOLLIN | EPOLLRDNORM, /* POLL_IN */
701 EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND, /* POLL_OUT */
702 EPOLLIN | EPOLLRDNORM | EPOLLMSG, /* POLL_MSG */
703 EPOLLERR, /* POLL_ERR */
704 EPOLLPRI | EPOLLRDBAND, /* POLL_PRI */
705 EPOLLHUP | EPOLLERR /* POLL_HUP */
706};
707
708static inline int sigio_perm(struct task_struct *p,
709 struct fown_struct *fown, int sig)
710{
711 const struct cred *cred;
712 int ret;
713
714 rcu_read_lock();
715 cred = __task_cred(p);
716 ret = ((uid_eq(fown->euid, GLOBAL_ROOT_UID) ||
717 uid_eq(fown->euid, cred->suid) || uid_eq(fown->euid, cred->uid) ||
718 uid_eq(fown->uid, cred->suid) || uid_eq(fown->uid, cred->uid)) &&
719 !security_file_send_sigiotask(p, fown, sig));
720 rcu_read_unlock();
721 return ret;
722}
723
724static void send_sigio_to_task(struct task_struct *p,
725 struct fown_struct *fown,
726 int fd, int reason, enum pid_type type)
727{
728 /*
729 * F_SETSIG can change ->signum lockless in parallel, make
730 * sure we read it once and use the same value throughout.
731 */
732 int signum = READ_ONCE(fown->signum);
733
734 if (!sigio_perm(p, fown, signum))
735 return;
736
737 switch (signum) {
738 default: {
739 kernel_siginfo_t si;
740
741 /* Queue a rt signal with the appropriate fd as its
742 value. We use SI_SIGIO as the source, not
743 SI_KERNEL, since kernel signals always get
744 delivered even if we can't queue. Failure to
745 queue in this case _should_ be reported; we fall
746 back to SIGIO in that case. --sct */
747 clear_siginfo(&si);
748 si.si_signo = signum;
749 si.si_errno = 0;
750 si.si_code = reason;
751 /*
752 * Posix definies POLL_IN and friends to be signal
753 * specific si_codes for SIG_POLL. Linux extended
754 * these si_codes to other signals in a way that is
755 * ambiguous if other signals also have signal
756 * specific si_codes. In that case use SI_SIGIO instead
757 * to remove the ambiguity.
758 */
759 if ((signum != SIGPOLL) && sig_specific_sicodes(signum))
760 si.si_code = SI_SIGIO;
761
762 /* Make sure we are called with one of the POLL_*
763 reasons, otherwise we could leak kernel stack into
764 userspace. */
765 BUG_ON((reason < POLL_IN) || ((reason - POLL_IN) >= NSIGPOLL));
766 if (reason - POLL_IN >= NSIGPOLL)
767 si.si_band = ~0L;
768 else
769 si.si_band = mangle_poll(band_table[reason - POLL_IN]);
770 si.si_fd = fd;
771 if (!do_send_sig_info(signum, &si, p, type))
772 break;
773 }
774 fallthrough; /* fall back on the old plain SIGIO signal */
775 case 0:
776 do_send_sig_info(SIGIO, SEND_SIG_PRIV, p, type);
777 }
778}
779
780void send_sigio(struct fown_struct *fown, int fd, int band)
781{
782 struct task_struct *p;
783 enum pid_type type;
784 struct pid *pid;
785
786 read_lock(&fown->lock);
787
788 type = fown->pid_type;
789 pid = fown->pid;
790 if (!pid)
791 goto out_unlock_fown;
792
793 if (type <= PIDTYPE_TGID) {
794 rcu_read_lock();
795 p = pid_task(pid, PIDTYPE_PID);
796 if (p)
797 send_sigio_to_task(p, fown, fd, band, type);
798 rcu_read_unlock();
799 } else {
800 read_lock(&tasklist_lock);
801 do_each_pid_task(pid, type, p) {
802 send_sigio_to_task(p, fown, fd, band, type);
803 } while_each_pid_task(pid, type, p);
804 read_unlock(&tasklist_lock);
805 }
806 out_unlock_fown:
807 read_unlock(&fown->lock);
808}
809
810static void send_sigurg_to_task(struct task_struct *p,
811 struct fown_struct *fown, enum pid_type type)
812{
813 if (sigio_perm(p, fown, SIGURG))
814 do_send_sig_info(SIGURG, SEND_SIG_PRIV, p, type);
815}
816
817int send_sigurg(struct fown_struct *fown)
818{
819 struct task_struct *p;
820 enum pid_type type;
821 struct pid *pid;
822 int ret = 0;
823
824 read_lock(&fown->lock);
825
826 type = fown->pid_type;
827 pid = fown->pid;
828 if (!pid)
829 goto out_unlock_fown;
830
831 ret = 1;
832
833 if (type <= PIDTYPE_TGID) {
834 rcu_read_lock();
835 p = pid_task(pid, PIDTYPE_PID);
836 if (p)
837 send_sigurg_to_task(p, fown, type);
838 rcu_read_unlock();
839 } else {
840 read_lock(&tasklist_lock);
841 do_each_pid_task(pid, type, p) {
842 send_sigurg_to_task(p, fown, type);
843 } while_each_pid_task(pid, type, p);
844 read_unlock(&tasklist_lock);
845 }
846 out_unlock_fown:
847 read_unlock(&fown->lock);
848 return ret;
849}
850
851static DEFINE_SPINLOCK(fasync_lock);
852static struct kmem_cache *fasync_cache __read_mostly;
853
854static void fasync_free_rcu(struct rcu_head *head)
855{
856 kmem_cache_free(fasync_cache,
857 container_of(head, struct fasync_struct, fa_rcu));
858}
859
860/*
861 * Remove a fasync entry. If successfully removed, return
862 * positive and clear the FASYNC flag. If no entry exists,
863 * do nothing and return 0.
864 *
865 * NOTE! It is very important that the FASYNC flag always
866 * match the state "is the filp on a fasync list".
867 *
868 */
869int fasync_remove_entry(struct file *filp, struct fasync_struct **fapp)
870{
871 struct fasync_struct *fa, **fp;
872 int result = 0;
873
874 spin_lock(&filp->f_lock);
875 spin_lock(&fasync_lock);
876 for (fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) {
877 if (fa->fa_file != filp)
878 continue;
879
880 write_lock_irq(&fa->fa_lock);
881 fa->fa_file = NULL;
882 write_unlock_irq(&fa->fa_lock);
883
884 *fp = fa->fa_next;
885 call_rcu(&fa->fa_rcu, fasync_free_rcu);
886 filp->f_flags &= ~FASYNC;
887 result = 1;
888 break;
889 }
890 spin_unlock(&fasync_lock);
891 spin_unlock(&filp->f_lock);
892 return result;
893}
894
895struct fasync_struct *fasync_alloc(void)
896{
897 return kmem_cache_alloc(fasync_cache, GFP_KERNEL);
898}
899
900/*
901 * NOTE! This can be used only for unused fasync entries:
902 * entries that actually got inserted on the fasync list
903 * need to be released by rcu - see fasync_remove_entry.
904 */
905void fasync_free(struct fasync_struct *new)
906{
907 kmem_cache_free(fasync_cache, new);
908}
909
910/*
911 * Insert a new entry into the fasync list. Return the pointer to the
912 * old one if we didn't use the new one.
913 *
914 * NOTE! It is very important that the FASYNC flag always
915 * match the state "is the filp on a fasync list".
916 */
917struct fasync_struct *fasync_insert_entry(int fd, struct file *filp, struct fasync_struct **fapp, struct fasync_struct *new)
918{
919 struct fasync_struct *fa, **fp;
920
921 spin_lock(&filp->f_lock);
922 spin_lock(&fasync_lock);
923 for (fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) {
924 if (fa->fa_file != filp)
925 continue;
926
927 write_lock_irq(&fa->fa_lock);
928 fa->fa_fd = fd;
929 write_unlock_irq(&fa->fa_lock);
930 goto out;
931 }
932
933 rwlock_init(&new->fa_lock);
934 new->magic = FASYNC_MAGIC;
935 new->fa_file = filp;
936 new->fa_fd = fd;
937 new->fa_next = *fapp;
938 rcu_assign_pointer(*fapp, new);
939 filp->f_flags |= FASYNC;
940
941out:
942 spin_unlock(&fasync_lock);
943 spin_unlock(&filp->f_lock);
944 return fa;
945}
946
947/*
948 * Add a fasync entry. Return negative on error, positive if
949 * added, and zero if did nothing but change an existing one.
950 */
951static int fasync_add_entry(int fd, struct file *filp, struct fasync_struct **fapp)
952{
953 struct fasync_struct *new;
954
955 new = fasync_alloc();
956 if (!new)
957 return -ENOMEM;
958
959 /*
960 * fasync_insert_entry() returns the old (update) entry if
961 * it existed.
962 *
963 * So free the (unused) new entry and return 0 to let the
964 * caller know that we didn't add any new fasync entries.
965 */
966 if (fasync_insert_entry(fd, filp, fapp, new)) {
967 fasync_free(new);
968 return 0;
969 }
970
971 return 1;
972}
973
974/*
975 * fasync_helper() is used by almost all character device drivers
976 * to set up the fasync queue, and for regular files by the file
977 * lease code. It returns negative on error, 0 if it did no changes
978 * and positive if it added/deleted the entry.
979 */
980int fasync_helper(int fd, struct file * filp, int on, struct fasync_struct **fapp)
981{
982 if (!on)
983 return fasync_remove_entry(filp, fapp);
984 return fasync_add_entry(fd, filp, fapp);
985}
986
987EXPORT_SYMBOL(fasync_helper);
988
989/*
990 * rcu_read_lock() is held
991 */
992static void kill_fasync_rcu(struct fasync_struct *fa, int sig, int band)
993{
994 while (fa) {
995 struct fown_struct *fown;
996
997 if (fa->magic != FASYNC_MAGIC) {
998 printk(KERN_ERR "kill_fasync: bad magic number in "
999 "fasync_struct!\n");
1000 return;
1001 }
1002 read_lock(&fa->fa_lock);
1003 if (fa->fa_file) {
1004 fown = &fa->fa_file->f_owner;
1005 /* Don't send SIGURG to processes which have not set a
1006 queued signum: SIGURG has its own default signalling
1007 mechanism. */
1008 if (!(sig == SIGURG && fown->signum == 0))
1009 send_sigio(fown, fa->fa_fd, band);
1010 }
1011 read_unlock(&fa->fa_lock);
1012 fa = rcu_dereference(fa->fa_next);
1013 }
1014}
1015
1016void kill_fasync(struct fasync_struct **fp, int sig, int band)
1017{
1018 /* First a quick test without locking: usually
1019 * the list is empty.
1020 */
1021 if (*fp) {
1022 rcu_read_lock();
1023 kill_fasync_rcu(rcu_dereference(*fp), sig, band);
1024 rcu_read_unlock();
1025 }
1026}
1027EXPORT_SYMBOL(kill_fasync);
1028
1029static int __init fcntl_init(void)
1030{
1031 /*
1032 * Please add new bits here to ensure allocation uniqueness.
1033 * Exceptions: O_NONBLOCK is a two bit define on parisc; O_NDELAY
1034 * is defined as O_NONBLOCK on some platforms and not on others.
1035 */
1036 BUILD_BUG_ON(21 - 1 /* for O_RDONLY being 0 */ !=
1037 HWEIGHT32(
1038 (VALID_OPEN_FLAGS & ~(O_NONBLOCK | O_NDELAY)) |
1039 __FMODE_EXEC | __FMODE_NONOTIFY));
1040
1041 fasync_cache = kmem_cache_create("fasync_cache",
1042 sizeof(struct fasync_struct), 0, SLAB_PANIC, NULL);
1043 return 0;
1044}
1045
1046module_init(fcntl_init)
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
24#include <asm/poll.h>
25#include <asm/siginfo.h>
26#include <asm/uaccess.h>
27
28void set_close_on_exec(unsigned int fd, int flag)
29{
30 struct files_struct *files = current->files;
31 struct fdtable *fdt;
32 spin_lock(&files->file_lock);
33 fdt = files_fdtable(files);
34 if (flag)
35 __set_close_on_exec(fd, fdt);
36 else
37 __clear_close_on_exec(fd, fdt);
38 spin_unlock(&files->file_lock);
39}
40
41static bool get_close_on_exec(unsigned int fd)
42{
43 struct files_struct *files = current->files;
44 struct fdtable *fdt;
45 bool res;
46 rcu_read_lock();
47 fdt = files_fdtable(files);
48 res = close_on_exec(fd, fdt);
49 rcu_read_unlock();
50 return res;
51}
52
53SYSCALL_DEFINE3(dup3, unsigned int, oldfd, unsigned int, newfd, int, flags)
54{
55 int err = -EBADF;
56 struct file * file, *tofree;
57 struct files_struct * files = current->files;
58 struct fdtable *fdt;
59
60 if ((flags & ~O_CLOEXEC) != 0)
61 return -EINVAL;
62
63 if (unlikely(oldfd == newfd))
64 return -EINVAL;
65
66 spin_lock(&files->file_lock);
67 err = expand_files(files, newfd);
68 file = fcheck(oldfd);
69 if (unlikely(!file))
70 goto Ebadf;
71 if (unlikely(err < 0)) {
72 if (err == -EMFILE)
73 goto Ebadf;
74 goto out_unlock;
75 }
76 /*
77 * We need to detect attempts to do dup2() over allocated but still
78 * not finished descriptor. NB: OpenBSD avoids that at the price of
79 * extra work in their equivalent of fget() - they insert struct
80 * file immediately after grabbing descriptor, mark it larval if
81 * more work (e.g. actual opening) is needed and make sure that
82 * fget() treats larval files as absent. Potentially interesting,
83 * but while extra work in fget() is trivial, locking implications
84 * and amount of surgery on open()-related paths in VFS are not.
85 * FreeBSD fails with -EBADF in the same situation, NetBSD "solution"
86 * deadlocks in rather amusing ways, AFAICS. All of that is out of
87 * scope of POSIX or SUS, since neither considers shared descriptor
88 * tables and this condition does not arise without those.
89 */
90 err = -EBUSY;
91 fdt = files_fdtable(files);
92 tofree = fdt->fd[newfd];
93 if (!tofree && fd_is_open(newfd, fdt))
94 goto out_unlock;
95 get_file(file);
96 rcu_assign_pointer(fdt->fd[newfd], file);
97 __set_open_fd(newfd, fdt);
98 if (flags & O_CLOEXEC)
99 __set_close_on_exec(newfd, fdt);
100 else
101 __clear_close_on_exec(newfd, fdt);
102 spin_unlock(&files->file_lock);
103
104 if (tofree)
105 filp_close(tofree, files);
106
107 return newfd;
108
109Ebadf:
110 err = -EBADF;
111out_unlock:
112 spin_unlock(&files->file_lock);
113 return err;
114}
115
116SYSCALL_DEFINE2(dup2, unsigned int, oldfd, unsigned int, newfd)
117{
118 if (unlikely(newfd == oldfd)) { /* corner case */
119 struct files_struct *files = current->files;
120 int retval = oldfd;
121
122 rcu_read_lock();
123 if (!fcheck_files(files, oldfd))
124 retval = -EBADF;
125 rcu_read_unlock();
126 return retval;
127 }
128 return sys_dup3(oldfd, newfd, 0);
129}
130
131SYSCALL_DEFINE1(dup, unsigned int, fildes)
132{
133 int ret = -EBADF;
134 struct file *file = fget_raw(fildes);
135
136 if (file) {
137 ret = get_unused_fd();
138 if (ret >= 0)
139 fd_install(ret, file);
140 else
141 fput(file);
142 }
143 return ret;
144}
145
146#define SETFL_MASK (O_APPEND | O_NONBLOCK | O_NDELAY | O_DIRECT | O_NOATIME)
147
148static int setfl(int fd, struct file * filp, unsigned long arg)
149{
150 struct inode * inode = filp->f_path.dentry->d_inode;
151 int error = 0;
152
153 /*
154 * O_APPEND cannot be cleared if the file is marked as append-only
155 * and the file is open for write.
156 */
157 if (((arg ^ filp->f_flags) & O_APPEND) && IS_APPEND(inode))
158 return -EPERM;
159
160 /* O_NOATIME can only be set by the owner or superuser */
161 if ((arg & O_NOATIME) && !(filp->f_flags & O_NOATIME))
162 if (!inode_owner_or_capable(inode))
163 return -EPERM;
164
165 /* required for strict SunOS emulation */
166 if (O_NONBLOCK != O_NDELAY)
167 if (arg & O_NDELAY)
168 arg |= O_NONBLOCK;
169
170 if (arg & O_DIRECT) {
171 if (!filp->f_mapping || !filp->f_mapping->a_ops ||
172 !filp->f_mapping->a_ops->direct_IO)
173 return -EINVAL;
174 }
175
176 if (filp->f_op && filp->f_op->check_flags)
177 error = filp->f_op->check_flags(arg);
178 if (error)
179 return error;
180
181 /*
182 * ->fasync() is responsible for setting the FASYNC bit.
183 */
184 if (((arg ^ filp->f_flags) & FASYNC) && filp->f_op &&
185 filp->f_op->fasync) {
186 error = filp->f_op->fasync(fd, filp, (arg & FASYNC) != 0);
187 if (error < 0)
188 goto out;
189 if (error > 0)
190 error = 0;
191 }
192 spin_lock(&filp->f_lock);
193 filp->f_flags = (arg & SETFL_MASK) | (filp->f_flags & ~SETFL_MASK);
194 spin_unlock(&filp->f_lock);
195
196 out:
197 return error;
198}
199
200static void f_modown(struct file *filp, struct pid *pid, enum pid_type type,
201 int force)
202{
203 write_lock_irq(&filp->f_owner.lock);
204 if (force || !filp->f_owner.pid) {
205 put_pid(filp->f_owner.pid);
206 filp->f_owner.pid = get_pid(pid);
207 filp->f_owner.pid_type = type;
208
209 if (pid) {
210 const struct cred *cred = current_cred();
211 filp->f_owner.uid = cred->uid;
212 filp->f_owner.euid = cred->euid;
213 }
214 }
215 write_unlock_irq(&filp->f_owner.lock);
216}
217
218int __f_setown(struct file *filp, struct pid *pid, enum pid_type type,
219 int force)
220{
221 int err;
222
223 err = security_file_set_fowner(filp);
224 if (err)
225 return err;
226
227 f_modown(filp, pid, type, force);
228 return 0;
229}
230EXPORT_SYMBOL(__f_setown);
231
232int f_setown(struct file *filp, unsigned long arg, int force)
233{
234 enum pid_type type;
235 struct pid *pid;
236 int who = arg;
237 int result;
238 type = PIDTYPE_PID;
239 if (who < 0) {
240 type = PIDTYPE_PGID;
241 who = -who;
242 }
243 rcu_read_lock();
244 pid = find_vpid(who);
245 result = __f_setown(filp, pid, type, force);
246 rcu_read_unlock();
247 return result;
248}
249EXPORT_SYMBOL(f_setown);
250
251void f_delown(struct file *filp)
252{
253 f_modown(filp, NULL, PIDTYPE_PID, 1);
254}
255
256pid_t f_getown(struct file *filp)
257{
258 pid_t pid;
259 read_lock(&filp->f_owner.lock);
260 pid = pid_vnr(filp->f_owner.pid);
261 if (filp->f_owner.pid_type == PIDTYPE_PGID)
262 pid = -pid;
263 read_unlock(&filp->f_owner.lock);
264 return pid;
265}
266
267static int f_setown_ex(struct file *filp, unsigned long arg)
268{
269 struct f_owner_ex * __user owner_p = (void * __user)arg;
270 struct f_owner_ex owner;
271 struct pid *pid;
272 int type;
273 int ret;
274
275 ret = copy_from_user(&owner, owner_p, sizeof(owner));
276 if (ret)
277 return -EFAULT;
278
279 switch (owner.type) {
280 case F_OWNER_TID:
281 type = PIDTYPE_MAX;
282 break;
283
284 case F_OWNER_PID:
285 type = PIDTYPE_PID;
286 break;
287
288 case F_OWNER_PGRP:
289 type = PIDTYPE_PGID;
290 break;
291
292 default:
293 return -EINVAL;
294 }
295
296 rcu_read_lock();
297 pid = find_vpid(owner.pid);
298 if (owner.pid && !pid)
299 ret = -ESRCH;
300 else
301 ret = __f_setown(filp, pid, type, 1);
302 rcu_read_unlock();
303
304 return ret;
305}
306
307static int f_getown_ex(struct file *filp, unsigned long arg)
308{
309 struct f_owner_ex * __user owner_p = (void * __user)arg;
310 struct f_owner_ex owner;
311 int ret = 0;
312
313 read_lock(&filp->f_owner.lock);
314 owner.pid = pid_vnr(filp->f_owner.pid);
315 switch (filp->f_owner.pid_type) {
316 case PIDTYPE_MAX:
317 owner.type = F_OWNER_TID;
318 break;
319
320 case PIDTYPE_PID:
321 owner.type = F_OWNER_PID;
322 break;
323
324 case PIDTYPE_PGID:
325 owner.type = F_OWNER_PGRP;
326 break;
327
328 default:
329 WARN_ON(1);
330 ret = -EINVAL;
331 break;
332 }
333 read_unlock(&filp->f_owner.lock);
334
335 if (!ret) {
336 ret = copy_to_user(owner_p, &owner, sizeof(owner));
337 if (ret)
338 ret = -EFAULT;
339 }
340 return ret;
341}
342
343static long do_fcntl(int fd, unsigned int cmd, unsigned long arg,
344 struct file *filp)
345{
346 long err = -EINVAL;
347
348 switch (cmd) {
349 case F_DUPFD:
350 case F_DUPFD_CLOEXEC:
351 if (arg >= rlimit(RLIMIT_NOFILE))
352 break;
353 err = alloc_fd(arg, cmd == F_DUPFD_CLOEXEC ? O_CLOEXEC : 0);
354 if (err >= 0) {
355 get_file(filp);
356 fd_install(err, filp);
357 }
358 break;
359 case F_GETFD:
360 err = get_close_on_exec(fd) ? FD_CLOEXEC : 0;
361 break;
362 case F_SETFD:
363 err = 0;
364 set_close_on_exec(fd, arg & FD_CLOEXEC);
365 break;
366 case F_GETFL:
367 err = filp->f_flags;
368 break;
369 case F_SETFL:
370 err = setfl(fd, filp, arg);
371 break;
372 case F_GETLK:
373 err = fcntl_getlk(filp, (struct flock __user *) arg);
374 break;
375 case F_SETLK:
376 case F_SETLKW:
377 err = fcntl_setlk(fd, filp, cmd, (struct flock __user *) arg);
378 break;
379 case F_GETOWN:
380 /*
381 * XXX If f_owner is a process group, the
382 * negative return value will get converted
383 * into an error. Oops. If we keep the
384 * current syscall conventions, the only way
385 * to fix this will be in libc.
386 */
387 err = f_getown(filp);
388 force_successful_syscall_return();
389 break;
390 case F_SETOWN:
391 err = f_setown(filp, arg, 1);
392 break;
393 case F_GETOWN_EX:
394 err = f_getown_ex(filp, arg);
395 break;
396 case F_SETOWN_EX:
397 err = f_setown_ex(filp, arg);
398 break;
399 case F_GETSIG:
400 err = filp->f_owner.signum;
401 break;
402 case F_SETSIG:
403 /* arg == 0 restores default behaviour. */
404 if (!valid_signal(arg)) {
405 break;
406 }
407 err = 0;
408 filp->f_owner.signum = arg;
409 break;
410 case F_GETLEASE:
411 err = fcntl_getlease(filp);
412 break;
413 case F_SETLEASE:
414 err = fcntl_setlease(fd, filp, arg);
415 break;
416 case F_NOTIFY:
417 err = fcntl_dirnotify(fd, filp, arg);
418 break;
419 case F_SETPIPE_SZ:
420 case F_GETPIPE_SZ:
421 err = pipe_fcntl(filp, cmd, arg);
422 break;
423 default:
424 break;
425 }
426 return err;
427}
428
429static int check_fcntl_cmd(unsigned cmd)
430{
431 switch (cmd) {
432 case F_DUPFD:
433 case F_DUPFD_CLOEXEC:
434 case F_GETFD:
435 case F_SETFD:
436 case F_GETFL:
437 return 1;
438 }
439 return 0;
440}
441
442SYSCALL_DEFINE3(fcntl, unsigned int, fd, unsigned int, cmd, unsigned long, arg)
443{
444 struct file *filp;
445 int fput_needed;
446 long err = -EBADF;
447
448 filp = fget_raw_light(fd, &fput_needed);
449 if (!filp)
450 goto out;
451
452 if (unlikely(filp->f_mode & FMODE_PATH)) {
453 if (!check_fcntl_cmd(cmd))
454 goto out1;
455 }
456
457 err = security_file_fcntl(filp, cmd, arg);
458 if (!err)
459 err = do_fcntl(fd, cmd, arg, filp);
460
461out1:
462 fput_light(filp, fput_needed);
463out:
464 return err;
465}
466
467#if BITS_PER_LONG == 32
468SYSCALL_DEFINE3(fcntl64, unsigned int, fd, unsigned int, cmd,
469 unsigned long, arg)
470{
471 struct file * filp;
472 long err = -EBADF;
473 int fput_needed;
474
475 filp = fget_raw_light(fd, &fput_needed);
476 if (!filp)
477 goto out;
478
479 if (unlikely(filp->f_mode & FMODE_PATH)) {
480 if (!check_fcntl_cmd(cmd))
481 goto out1;
482 }
483
484 err = security_file_fcntl(filp, cmd, arg);
485 if (err)
486 goto out1;
487
488 switch (cmd) {
489 case F_GETLK64:
490 err = fcntl_getlk64(filp, (struct flock64 __user *) arg);
491 break;
492 case F_SETLK64:
493 case F_SETLKW64:
494 err = fcntl_setlk64(fd, filp, cmd,
495 (struct flock64 __user *) arg);
496 break;
497 default:
498 err = do_fcntl(fd, cmd, arg, filp);
499 break;
500 }
501out1:
502 fput_light(filp, fput_needed);
503out:
504 return err;
505}
506#endif
507
508/* Table to convert sigio signal codes into poll band bitmaps */
509
510static const long band_table[NSIGPOLL] = {
511 POLLIN | POLLRDNORM, /* POLL_IN */
512 POLLOUT | POLLWRNORM | POLLWRBAND, /* POLL_OUT */
513 POLLIN | POLLRDNORM | POLLMSG, /* POLL_MSG */
514 POLLERR, /* POLL_ERR */
515 POLLPRI | POLLRDBAND, /* POLL_PRI */
516 POLLHUP | POLLERR /* POLL_HUP */
517};
518
519static inline int sigio_perm(struct task_struct *p,
520 struct fown_struct *fown, int sig)
521{
522 const struct cred *cred;
523 int ret;
524
525 rcu_read_lock();
526 cred = __task_cred(p);
527 ret = ((uid_eq(fown->euid, GLOBAL_ROOT_UID) ||
528 uid_eq(fown->euid, cred->suid) || uid_eq(fown->euid, cred->uid) ||
529 uid_eq(fown->uid, cred->suid) || uid_eq(fown->uid, cred->uid)) &&
530 !security_file_send_sigiotask(p, fown, sig));
531 rcu_read_unlock();
532 return ret;
533}
534
535static void send_sigio_to_task(struct task_struct *p,
536 struct fown_struct *fown,
537 int fd, int reason, int group)
538{
539 /*
540 * F_SETSIG can change ->signum lockless in parallel, make
541 * sure we read it once and use the same value throughout.
542 */
543 int signum = ACCESS_ONCE(fown->signum);
544
545 if (!sigio_perm(p, fown, signum))
546 return;
547
548 switch (signum) {
549 siginfo_t si;
550 default:
551 /* Queue a rt signal with the appropriate fd as its
552 value. We use SI_SIGIO as the source, not
553 SI_KERNEL, since kernel signals always get
554 delivered even if we can't queue. Failure to
555 queue in this case _should_ be reported; we fall
556 back to SIGIO in that case. --sct */
557 si.si_signo = signum;
558 si.si_errno = 0;
559 si.si_code = reason;
560 /* Make sure we are called with one of the POLL_*
561 reasons, otherwise we could leak kernel stack into
562 userspace. */
563 BUG_ON((reason & __SI_MASK) != __SI_POLL);
564 if (reason - POLL_IN >= NSIGPOLL)
565 si.si_band = ~0L;
566 else
567 si.si_band = band_table[reason - POLL_IN];
568 si.si_fd = fd;
569 if (!do_send_sig_info(signum, &si, p, group))
570 break;
571 /* fall-through: fall back on the old plain SIGIO signal */
572 case 0:
573 do_send_sig_info(SIGIO, SEND_SIG_PRIV, p, group);
574 }
575}
576
577void send_sigio(struct fown_struct *fown, int fd, int band)
578{
579 struct task_struct *p;
580 enum pid_type type;
581 struct pid *pid;
582 int group = 1;
583
584 read_lock(&fown->lock);
585
586 type = fown->pid_type;
587 if (type == PIDTYPE_MAX) {
588 group = 0;
589 type = PIDTYPE_PID;
590 }
591
592 pid = fown->pid;
593 if (!pid)
594 goto out_unlock_fown;
595
596 read_lock(&tasklist_lock);
597 do_each_pid_task(pid, type, p) {
598 send_sigio_to_task(p, fown, fd, band, group);
599 } while_each_pid_task(pid, type, p);
600 read_unlock(&tasklist_lock);
601 out_unlock_fown:
602 read_unlock(&fown->lock);
603}
604
605static void send_sigurg_to_task(struct task_struct *p,
606 struct fown_struct *fown, int group)
607{
608 if (sigio_perm(p, fown, SIGURG))
609 do_send_sig_info(SIGURG, SEND_SIG_PRIV, p, group);
610}
611
612int send_sigurg(struct fown_struct *fown)
613{
614 struct task_struct *p;
615 enum pid_type type;
616 struct pid *pid;
617 int group = 1;
618 int ret = 0;
619
620 read_lock(&fown->lock);
621
622 type = fown->pid_type;
623 if (type == PIDTYPE_MAX) {
624 group = 0;
625 type = PIDTYPE_PID;
626 }
627
628 pid = fown->pid;
629 if (!pid)
630 goto out_unlock_fown;
631
632 ret = 1;
633
634 read_lock(&tasklist_lock);
635 do_each_pid_task(pid, type, p) {
636 send_sigurg_to_task(p, fown, group);
637 } while_each_pid_task(pid, type, p);
638 read_unlock(&tasklist_lock);
639 out_unlock_fown:
640 read_unlock(&fown->lock);
641 return ret;
642}
643
644static DEFINE_SPINLOCK(fasync_lock);
645static struct kmem_cache *fasync_cache __read_mostly;
646
647static void fasync_free_rcu(struct rcu_head *head)
648{
649 kmem_cache_free(fasync_cache,
650 container_of(head, struct fasync_struct, fa_rcu));
651}
652
653/*
654 * Remove a fasync entry. If successfully removed, return
655 * positive and clear the FASYNC flag. If no entry exists,
656 * do nothing and return 0.
657 *
658 * NOTE! It is very important that the FASYNC flag always
659 * match the state "is the filp on a fasync list".
660 *
661 */
662int fasync_remove_entry(struct file *filp, struct fasync_struct **fapp)
663{
664 struct fasync_struct *fa, **fp;
665 int result = 0;
666
667 spin_lock(&filp->f_lock);
668 spin_lock(&fasync_lock);
669 for (fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) {
670 if (fa->fa_file != filp)
671 continue;
672
673 spin_lock_irq(&fa->fa_lock);
674 fa->fa_file = NULL;
675 spin_unlock_irq(&fa->fa_lock);
676
677 *fp = fa->fa_next;
678 call_rcu(&fa->fa_rcu, fasync_free_rcu);
679 filp->f_flags &= ~FASYNC;
680 result = 1;
681 break;
682 }
683 spin_unlock(&fasync_lock);
684 spin_unlock(&filp->f_lock);
685 return result;
686}
687
688struct fasync_struct *fasync_alloc(void)
689{
690 return kmem_cache_alloc(fasync_cache, GFP_KERNEL);
691}
692
693/*
694 * NOTE! This can be used only for unused fasync entries:
695 * entries that actually got inserted on the fasync list
696 * need to be released by rcu - see fasync_remove_entry.
697 */
698void fasync_free(struct fasync_struct *new)
699{
700 kmem_cache_free(fasync_cache, new);
701}
702
703/*
704 * Insert a new entry into the fasync list. Return the pointer to the
705 * old one if we didn't use the new one.
706 *
707 * NOTE! It is very important that the FASYNC flag always
708 * match the state "is the filp on a fasync list".
709 */
710struct fasync_struct *fasync_insert_entry(int fd, struct file *filp, struct fasync_struct **fapp, struct fasync_struct *new)
711{
712 struct fasync_struct *fa, **fp;
713
714 spin_lock(&filp->f_lock);
715 spin_lock(&fasync_lock);
716 for (fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) {
717 if (fa->fa_file != filp)
718 continue;
719
720 spin_lock_irq(&fa->fa_lock);
721 fa->fa_fd = fd;
722 spin_unlock_irq(&fa->fa_lock);
723 goto out;
724 }
725
726 spin_lock_init(&new->fa_lock);
727 new->magic = FASYNC_MAGIC;
728 new->fa_file = filp;
729 new->fa_fd = fd;
730 new->fa_next = *fapp;
731 rcu_assign_pointer(*fapp, new);
732 filp->f_flags |= FASYNC;
733
734out:
735 spin_unlock(&fasync_lock);
736 spin_unlock(&filp->f_lock);
737 return fa;
738}
739
740/*
741 * Add a fasync entry. Return negative on error, positive if
742 * added, and zero if did nothing but change an existing one.
743 */
744static int fasync_add_entry(int fd, struct file *filp, struct fasync_struct **fapp)
745{
746 struct fasync_struct *new;
747
748 new = fasync_alloc();
749 if (!new)
750 return -ENOMEM;
751
752 /*
753 * fasync_insert_entry() returns the old (update) entry if
754 * it existed.
755 *
756 * So free the (unused) new entry and return 0 to let the
757 * caller know that we didn't add any new fasync entries.
758 */
759 if (fasync_insert_entry(fd, filp, fapp, new)) {
760 fasync_free(new);
761 return 0;
762 }
763
764 return 1;
765}
766
767/*
768 * fasync_helper() is used by almost all character device drivers
769 * to set up the fasync queue, and for regular files by the file
770 * lease code. It returns negative on error, 0 if it did no changes
771 * and positive if it added/deleted the entry.
772 */
773int fasync_helper(int fd, struct file * filp, int on, struct fasync_struct **fapp)
774{
775 if (!on)
776 return fasync_remove_entry(filp, fapp);
777 return fasync_add_entry(fd, filp, fapp);
778}
779
780EXPORT_SYMBOL(fasync_helper);
781
782/*
783 * rcu_read_lock() is held
784 */
785static void kill_fasync_rcu(struct fasync_struct *fa, int sig, int band)
786{
787 while (fa) {
788 struct fown_struct *fown;
789 unsigned long flags;
790
791 if (fa->magic != FASYNC_MAGIC) {
792 printk(KERN_ERR "kill_fasync: bad magic number in "
793 "fasync_struct!\n");
794 return;
795 }
796 spin_lock_irqsave(&fa->fa_lock, flags);
797 if (fa->fa_file) {
798 fown = &fa->fa_file->f_owner;
799 /* Don't send SIGURG to processes which have not set a
800 queued signum: SIGURG has its own default signalling
801 mechanism. */
802 if (!(sig == SIGURG && fown->signum == 0))
803 send_sigio(fown, fa->fa_fd, band);
804 }
805 spin_unlock_irqrestore(&fa->fa_lock, flags);
806 fa = rcu_dereference(fa->fa_next);
807 }
808}
809
810void kill_fasync(struct fasync_struct **fp, int sig, int band)
811{
812 /* First a quick test without locking: usually
813 * the list is empty.
814 */
815 if (*fp) {
816 rcu_read_lock();
817 kill_fasync_rcu(rcu_dereference(*fp), sig, band);
818 rcu_read_unlock();
819 }
820}
821EXPORT_SYMBOL(kill_fasync);
822
823static int __init fcntl_init(void)
824{
825 /*
826 * Please add new bits here to ensure allocation uniqueness.
827 * Exceptions: O_NONBLOCK is a two bit define on parisc; O_NDELAY
828 * is defined as O_NONBLOCK on some platforms and not on others.
829 */
830 BUILD_BUG_ON(19 - 1 /* for O_RDONLY being 0 */ != HWEIGHT32(
831 O_RDONLY | O_WRONLY | O_RDWR |
832 O_CREAT | O_EXCL | O_NOCTTY |
833 O_TRUNC | O_APPEND | /* O_NONBLOCK | */
834 __O_SYNC | O_DSYNC | FASYNC |
835 O_DIRECT | O_LARGEFILE | O_DIRECTORY |
836 O_NOFOLLOW | O_NOATIME | O_CLOEXEC |
837 __FMODE_EXEC | O_PATH
838 ));
839
840 fasync_cache = kmem_cache_create("fasync_cache",
841 sizeof(struct fasync_struct), 0, SLAB_PANIC, NULL);
842 return 0;
843}
844
845module_init(fcntl_init)