~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

TOMOYO Linux Cross Reference
Linux/fs/fcntl.c

Version: ~ [ linux-5.11 ] ~ [ linux-5.10.17 ] ~ [ linux-5.9.16 ] ~ [ linux-5.8.18 ] ~ [ linux-5.7.19 ] ~ [ linux-5.6.19 ] ~ [ linux-5.5.19 ] ~ [ linux-5.4.99 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.176 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.221 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.257 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.257 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.140 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.85 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

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

~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

kernel.org | git.kernel.org | LWN.net | Project Home | Wiki (Japanese) | Wiki (English) | SVN repository | Mail admin

Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.

osdn.jp