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

TOMOYO Linux Cross Reference
Linux/fs/fcntl.c

Version: ~ [ linux-5.4-rc3 ] ~ [ linux-5.3.6 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.79 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.149 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.196 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.196 ] ~ [ 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-3.16.75 ] ~ [ 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-3.9.11 ] ~ [ linux-3.8.13 ] ~ [ linux-3.7.10 ] ~ [ linux-3.6.11 ] ~ [ linux-3.5.7 ] ~ [ linux-3.4.113 ] ~ [ linux-3.3.8 ] ~ [ linux-3.2.102 ] ~ [ linux-3.1.10 ] ~ [ linux-3.0.101 ] ~ [ 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/sched/task.h>
 11 #include <linux/fs.h>
 12 #include <linux/file.h>
 13 #include <linux/fdtable.h>
 14 #include <linux/capability.h>
 15 #include <linux/dnotify.h>
 16 #include <linux/slab.h>
 17 #include <linux/module.h>
 18 #include <linux/pipe_fs_i.h>
 19 #include <linux/security.h>
 20 #include <linux/ptrace.h>
 21 #include <linux/signal.h>
 22 #include <linux/rcupdate.h>
 23 #include <linux/pid_namespace.h>
 24 #include <linux/user_namespace.h>
 25 #include <linux/shmem_fs.h>
 26 #include <linux/compat.h>
 27 
 28 #include <asm/poll.h>
 29 #include <asm/siginfo.h>
 30 #include <linux/uaccess.h>
 31 
 32 #define SETFL_MASK (O_APPEND | O_NONBLOCK | O_NDELAY | O_DIRECT | O_NOATIME)
 33 
 34 static int setfl(int fd, struct file * filp, unsigned long arg)
 35 {
 36         struct inode * inode = file_inode(filp);
 37         int error = 0;
 38 
 39         /*
 40          * O_APPEND cannot be cleared if the file is marked as append-only
 41          * and the file is open for write.
 42          */
 43         if (((arg ^ filp->f_flags) & O_APPEND) && IS_APPEND(inode))
 44                 return -EPERM;
 45 
 46         /* O_NOATIME can only be set by the owner or superuser */
 47         if ((arg & O_NOATIME) && !(filp->f_flags & O_NOATIME))
 48                 if (!inode_owner_or_capable(inode))
 49                         return -EPERM;
 50 
 51         /* required for strict SunOS emulation */
 52         if (O_NONBLOCK != O_NDELAY)
 53                if (arg & O_NDELAY)
 54                    arg |= O_NONBLOCK;
 55 
 56         /* Pipe packetized mode is controlled by O_DIRECT flag */
 57         if (!S_ISFIFO(inode->i_mode) && (arg & O_DIRECT)) {
 58                 if (!filp->f_mapping || !filp->f_mapping->a_ops ||
 59                         !filp->f_mapping->a_ops->direct_IO)
 60                                 return -EINVAL;
 61         }
 62 
 63         if (filp->f_op->check_flags)
 64                 error = filp->f_op->check_flags(arg);
 65         if (error)
 66                 return error;
 67 
 68         /*
 69          * ->fasync() is responsible for setting the FASYNC bit.
 70          */
 71         if (((arg ^ filp->f_flags) & FASYNC) && filp->f_op->fasync) {
 72                 error = filp->f_op->fasync(fd, filp, (arg & FASYNC) != 0);
 73                 if (error < 0)
 74                         goto out;
 75                 if (error > 0)
 76                         error = 0;
 77         }
 78         spin_lock(&filp->f_lock);
 79         filp->f_flags = (arg & SETFL_MASK) | (filp->f_flags & ~SETFL_MASK);
 80         spin_unlock(&filp->f_lock);
 81 
 82  out:
 83         return error;
 84 }
 85 
 86 static void f_modown(struct file *filp, struct pid *pid, enum pid_type type,
 87                      int force)
 88 {
 89         write_lock_irq(&filp->f_owner.lock);
 90         if (force || !filp->f_owner.pid) {
 91                 put_pid(filp->f_owner.pid);
 92                 filp->f_owner.pid = get_pid(pid);
 93                 filp->f_owner.pid_type = type;
 94 
 95                 if (pid) {
 96                         const struct cred *cred = current_cred();
 97                         filp->f_owner.uid = cred->uid;
 98                         filp->f_owner.euid = cred->euid;
 99                 }
100         }
101         write_unlock_irq(&filp->f_owner.lock);
102 }
103 
104 void __f_setown(struct file *filp, struct pid *pid, enum pid_type type,
105                 int force)
106 {
107         security_file_set_fowner(filp);
108         f_modown(filp, pid, type, force);
109 }
110 EXPORT_SYMBOL(__f_setown);
111 
112 int f_setown(struct file *filp, unsigned long arg, int force)
113 {
114         enum pid_type type;
115         struct pid *pid = NULL;
116         int who = arg, ret = 0;
117 
118         type = PIDTYPE_PID;
119         if (who < 0) {
120                 /* avoid overflow below */
121                 if (who == INT_MIN)
122                         return -EINVAL;
123 
124                 type = PIDTYPE_PGID;
125                 who = -who;
126         }
127 
128         rcu_read_lock();
129         if (who) {
130                 pid = find_vpid(who);
131                 if (!pid)
132                         ret = -ESRCH;
133         }
134 
135         if (!ret)
136                 __f_setown(filp, pid, type, force);
137         rcu_read_unlock();
138 
139         return ret;
140 }
141 EXPORT_SYMBOL(f_setown);
142 
143 void f_delown(struct file *filp)
144 {
145         f_modown(filp, NULL, PIDTYPE_PID, 1);
146 }
147 
148 pid_t f_getown(struct file *filp)
149 {
150         pid_t pid;
151         read_lock(&filp->f_owner.lock);
152         pid = pid_vnr(filp->f_owner.pid);
153         if (filp->f_owner.pid_type == PIDTYPE_PGID)
154                 pid = -pid;
155         read_unlock(&filp->f_owner.lock);
156         return pid;
157 }
158 
159 static int f_setown_ex(struct file *filp, unsigned long arg)
160 {
161         struct f_owner_ex __user *owner_p = (void __user *)arg;
162         struct f_owner_ex owner;
163         struct pid *pid;
164         int type;
165         int ret;
166 
167         ret = copy_from_user(&owner, owner_p, sizeof(owner));
168         if (ret)
169                 return -EFAULT;
170 
171         switch (owner.type) {
172         case F_OWNER_TID:
173                 type = PIDTYPE_MAX;
174                 break;
175 
176         case F_OWNER_PID:
177                 type = PIDTYPE_PID;
178                 break;
179 
180         case F_OWNER_PGRP:
181                 type = PIDTYPE_PGID;
182                 break;
183 
184         default:
185                 return -EINVAL;
186         }
187 
188         rcu_read_lock();
189         pid = find_vpid(owner.pid);
190         if (owner.pid && !pid)
191                 ret = -ESRCH;
192         else
193                  __f_setown(filp, pid, type, 1);
194         rcu_read_unlock();
195 
196         return ret;
197 }
198 
199 static int f_getown_ex(struct file *filp, unsigned long arg)
200 {
201         struct f_owner_ex __user *owner_p = (void __user *)arg;
202         struct f_owner_ex owner;
203         int ret = 0;
204 
205         read_lock(&filp->f_owner.lock);
206         owner.pid = pid_vnr(filp->f_owner.pid);
207         switch (filp->f_owner.pid_type) {
208         case PIDTYPE_MAX:
209                 owner.type = F_OWNER_TID;
210                 break;
211 
212         case PIDTYPE_PID:
213                 owner.type = F_OWNER_PID;
214                 break;
215 
216         case PIDTYPE_PGID:
217                 owner.type = F_OWNER_PGRP;
218                 break;
219 
220         default:
221                 WARN_ON(1);
222                 ret = -EINVAL;
223                 break;
224         }
225         read_unlock(&filp->f_owner.lock);
226 
227         if (!ret) {
228                 ret = copy_to_user(owner_p, &owner, sizeof(owner));
229                 if (ret)
230                         ret = -EFAULT;
231         }
232         return ret;
233 }
234 
235 #ifdef CONFIG_CHECKPOINT_RESTORE
236 static int f_getowner_uids(struct file *filp, unsigned long arg)
237 {
238         struct user_namespace *user_ns = current_user_ns();
239         uid_t __user *dst = (void __user *)arg;
240         uid_t src[2];
241         int err;
242 
243         read_lock(&filp->f_owner.lock);
244         src[0] = from_kuid(user_ns, filp->f_owner.uid);
245         src[1] = from_kuid(user_ns, filp->f_owner.euid);
246         read_unlock(&filp->f_owner.lock);
247 
248         err  = put_user(src[0], &dst[0]);
249         err |= put_user(src[1], &dst[1]);
250 
251         return err;
252 }
253 #else
254 static int f_getowner_uids(struct file *filp, unsigned long arg)
255 {
256         return -EINVAL;
257 }
258 #endif
259 
260 static bool rw_hint_valid(enum rw_hint hint)
261 {
262         switch (hint) {
263         case RWF_WRITE_LIFE_NOT_SET:
264         case RWH_WRITE_LIFE_NONE:
265         case RWH_WRITE_LIFE_SHORT:
266         case RWH_WRITE_LIFE_MEDIUM:
267         case RWH_WRITE_LIFE_LONG:
268         case RWH_WRITE_LIFE_EXTREME:
269                 return true;
270         default:
271                 return false;
272         }
273 }
274 
275 static long fcntl_rw_hint(struct file *file, unsigned int cmd,
276                           unsigned long arg)
277 {
278         struct inode *inode = file_inode(file);
279         u64 *argp = (u64 __user *)arg;
280         enum rw_hint hint;
281         u64 h;
282 
283         switch (cmd) {
284         case F_GET_FILE_RW_HINT:
285                 h = file_write_hint(file);
286                 if (copy_to_user(argp, &h, sizeof(*argp)))
287                         return -EFAULT;
288                 return 0;
289         case F_SET_FILE_RW_HINT:
290                 if (copy_from_user(&h, argp, sizeof(h)))
291                         return -EFAULT;
292                 hint = (enum rw_hint) h;
293                 if (!rw_hint_valid(hint))
294                         return -EINVAL;
295 
296                 spin_lock(&file->f_lock);
297                 file->f_write_hint = hint;
298                 spin_unlock(&file->f_lock);
299                 return 0;
300         case F_GET_RW_HINT:
301                 h = inode->i_write_hint;
302                 if (copy_to_user(argp, &h, sizeof(*argp)))
303                         return -EFAULT;
304                 return 0;
305         case F_SET_RW_HINT:
306                 if (copy_from_user(&h, argp, sizeof(h)))
307                         return -EFAULT;
308                 hint = (enum rw_hint) h;
309                 if (!rw_hint_valid(hint))
310                         return -EINVAL;
311 
312                 inode_lock(inode);
313                 inode->i_write_hint = hint;
314                 inode_unlock(inode);
315                 return 0;
316         default:
317                 return -EINVAL;
318         }
319 }
320 
321 static long do_fcntl(int fd, unsigned int cmd, unsigned long arg,
322                 struct file *filp)
323 {
324         void __user *argp = (void __user *)arg;
325         struct flock flock;
326         long err = -EINVAL;
327 
328         switch (cmd) {
329         case F_DUPFD:
330                 err = f_dupfd(arg, filp, 0);
331                 break;
332         case F_DUPFD_CLOEXEC:
333                 err = f_dupfd(arg, filp, O_CLOEXEC);
334                 break;
335         case F_GETFD:
336                 err = get_close_on_exec(fd) ? FD_CLOEXEC : 0;
337                 break;
338         case F_SETFD:
339                 err = 0;
340                 set_close_on_exec(fd, arg & FD_CLOEXEC);
341                 break;
342         case F_GETFL:
343                 err = filp->f_flags;
344                 break;
345         case F_SETFL:
346                 err = setfl(fd, filp, arg);
347                 break;
348 #if BITS_PER_LONG != 32
349         /* 32-bit arches must use fcntl64() */
350         case F_OFD_GETLK:
351 #endif
352         case F_GETLK:
353                 if (copy_from_user(&flock, argp, sizeof(flock)))
354                         return -EFAULT;
355                 err = fcntl_getlk(filp, cmd, &flock);
356                 if (!err && copy_to_user(argp, &flock, sizeof(flock)))
357                         return -EFAULT;
358                 break;
359 #if BITS_PER_LONG != 32
360         /* 32-bit arches must use fcntl64() */
361         case F_OFD_SETLK:
362         case F_OFD_SETLKW:
363 #endif
364                 /* Fallthrough */
365         case F_SETLK:
366         case F_SETLKW:
367                 if (copy_from_user(&flock, argp, sizeof(flock)))
368                         return -EFAULT;
369                 err = fcntl_setlk(fd, filp, cmd, &flock);
370                 break;
371         case F_GETOWN:
372                 /*
373                  * XXX If f_owner is a process group, the
374                  * negative return value will get converted
375                  * into an error.  Oops.  If we keep the
376                  * current syscall conventions, the only way
377                  * to fix this will be in libc.
378                  */
379                 err = f_getown(filp);
380                 force_successful_syscall_return();
381                 break;
382         case F_SETOWN:
383                 err = f_setown(filp, arg, 1);
384                 break;
385         case F_GETOWN_EX:
386                 err = f_getown_ex(filp, arg);
387                 break;
388         case F_SETOWN_EX:
389                 err = f_setown_ex(filp, arg);
390                 break;
391         case F_GETOWNER_UIDS:
392                 err = f_getowner_uids(filp, arg);
393                 break;
394         case F_GETSIG:
395                 err = filp->f_owner.signum;
396                 break;
397         case F_SETSIG:
398                 /* arg == 0 restores default behaviour. */
399                 if (!valid_signal(arg)) {
400                         break;
401                 }
402                 err = 0;
403                 filp->f_owner.signum = arg;
404                 break;
405         case F_GETLEASE:
406                 err = fcntl_getlease(filp);
407                 break;
408         case F_SETLEASE:
409                 err = fcntl_setlease(fd, filp, arg);
410                 break;
411         case F_NOTIFY:
412                 err = fcntl_dirnotify(fd, filp, arg);
413                 break;
414         case F_SETPIPE_SZ:
415         case F_GETPIPE_SZ:
416                 err = pipe_fcntl(filp, cmd, arg);
417                 break;
418         case F_ADD_SEALS:
419         case F_GET_SEALS:
420                 err = shmem_fcntl(filp, cmd, arg);
421                 break;
422         case F_GET_RW_HINT:
423         case F_SET_RW_HINT:
424         case F_GET_FILE_RW_HINT:
425         case F_SET_FILE_RW_HINT:
426                 err = fcntl_rw_hint(filp, cmd, arg);
427                 break;
428         default:
429                 break;
430         }
431         return err;
432 }
433 
434 static int check_fcntl_cmd(unsigned cmd)
435 {
436         switch (cmd) {
437         case F_DUPFD:
438         case F_DUPFD_CLOEXEC:
439         case F_GETFD:
440         case F_SETFD:
441         case F_GETFL:
442                 return 1;
443         }
444         return 0;
445 }
446 
447 SYSCALL_DEFINE3(fcntl, unsigned int, fd, unsigned int, cmd, unsigned long, arg)
448 {       
449         struct fd f = fdget_raw(fd);
450         long err = -EBADF;
451 
452         if (!f.file)
453                 goto out;
454 
455         if (unlikely(f.file->f_mode & FMODE_PATH)) {
456                 if (!check_fcntl_cmd(cmd))
457                         goto out1;
458         }
459 
460         err = security_file_fcntl(f.file, cmd, arg);
461         if (!err)
462                 err = do_fcntl(fd, cmd, arg, f.file);
463 
464 out1:
465         fdput(f);
466 out:
467         return err;
468 }
469 
470 #if BITS_PER_LONG == 32
471 SYSCALL_DEFINE3(fcntl64, unsigned int, fd, unsigned int, cmd,
472                 unsigned long, arg)
473 {       
474         void __user *argp = (void __user *)arg;
475         struct fd f = fdget_raw(fd);
476         struct flock64 flock;
477         long err = -EBADF;
478 
479         if (!f.file)
480                 goto out;
481 
482         if (unlikely(f.file->f_mode & FMODE_PATH)) {
483                 if (!check_fcntl_cmd(cmd))
484                         goto out1;
485         }
486 
487         err = security_file_fcntl(f.file, cmd, arg);
488         if (err)
489                 goto out1;
490         
491         switch (cmd) {
492         case F_GETLK64:
493         case F_OFD_GETLK:
494                 err = -EFAULT;
495                 if (copy_from_user(&flock, argp, sizeof(flock)))
496                         break;
497                 err = fcntl_getlk64(f.file, cmd, &flock);
498                 if (!err && copy_to_user(argp, &flock, sizeof(flock)))
499                         err = -EFAULT;
500                 break;
501         case F_SETLK64:
502         case F_SETLKW64:
503         case F_OFD_SETLK:
504         case F_OFD_SETLKW:
505                 err = -EFAULT;
506                 if (copy_from_user(&flock, argp, sizeof(flock)))
507                         break;
508                 err = fcntl_setlk64(fd, f.file, cmd, &flock);
509                 break;
510         default:
511                 err = do_fcntl(fd, cmd, arg, f.file);
512                 break;
513         }
514 out1:
515         fdput(f);
516 out:
517         return err;
518 }
519 #endif
520 
521 #ifdef CONFIG_COMPAT
522 /* careful - don't use anywhere else */
523 #define copy_flock_fields(dst, src)             \
524         (dst)->l_type = (src)->l_type;          \
525         (dst)->l_whence = (src)->l_whence;      \
526         (dst)->l_start = (src)->l_start;        \
527         (dst)->l_len = (src)->l_len;            \
528         (dst)->l_pid = (src)->l_pid;
529 
530 static int get_compat_flock(struct flock *kfl, const struct compat_flock __user *ufl)
531 {
532         struct compat_flock fl;
533 
534         if (copy_from_user(&fl, ufl, sizeof(struct compat_flock)))
535                 return -EFAULT;
536         copy_flock_fields(kfl, &fl);
537         return 0;
538 }
539 
540 static int get_compat_flock64(struct flock *kfl, const struct compat_flock64 __user *ufl)
541 {
542         struct compat_flock64 fl;
543 
544         if (copy_from_user(&fl, ufl, sizeof(struct compat_flock64)))
545                 return -EFAULT;
546         copy_flock_fields(kfl, &fl);
547         return 0;
548 }
549 
550 static int put_compat_flock(const struct flock *kfl, struct compat_flock __user *ufl)
551 {
552         struct compat_flock fl;
553 
554         memset(&fl, 0, sizeof(struct compat_flock));
555         copy_flock_fields(&fl, kfl);
556         if (copy_to_user(ufl, &fl, sizeof(struct compat_flock)))
557                 return -EFAULT;
558         return 0;
559 }
560 
561 static int put_compat_flock64(const struct flock *kfl, struct compat_flock64 __user *ufl)
562 {
563         struct compat_flock64 fl;
564 
565         memset(&fl, 0, sizeof(struct compat_flock64));
566         copy_flock_fields(&fl, kfl);
567         if (copy_to_user(ufl, &fl, sizeof(struct compat_flock64)))
568                 return -EFAULT;
569         return 0;
570 }
571 #undef copy_flock_fields
572 
573 static unsigned int
574 convert_fcntl_cmd(unsigned int cmd)
575 {
576         switch (cmd) {
577         case F_GETLK64:
578                 return F_GETLK;
579         case F_SETLK64:
580                 return F_SETLK;
581         case F_SETLKW64:
582                 return F_SETLKW;
583         }
584 
585         return cmd;
586 }
587 
588 /*
589  * GETLK was successful and we need to return the data, but it needs to fit in
590  * the compat structure.
591  * l_start shouldn't be too big, unless the original start + end is greater than
592  * COMPAT_OFF_T_MAX, in which case the app was asking for trouble, so we return
593  * -EOVERFLOW in that case.  l_len could be too big, in which case we just
594  * truncate it, and only allow the app to see that part of the conflicting lock
595  * that might make sense to it anyway
596  */
597 static int fixup_compat_flock(struct flock *flock)
598 {
599         if (flock->l_start > COMPAT_OFF_T_MAX)
600                 return -EOVERFLOW;
601         if (flock->l_len > COMPAT_OFF_T_MAX)
602                 flock->l_len = COMPAT_OFF_T_MAX;
603         return 0;
604 }
605 
606 COMPAT_SYSCALL_DEFINE3(fcntl64, unsigned int, fd, unsigned int, cmd,
607                        compat_ulong_t, arg)
608 {
609         struct fd f = fdget_raw(fd);
610         struct flock flock;
611         long err = -EBADF;
612 
613         if (!f.file)
614                 return err;
615 
616         if (unlikely(f.file->f_mode & FMODE_PATH)) {
617                 if (!check_fcntl_cmd(cmd))
618                         goto out_put;
619         }
620 
621         err = security_file_fcntl(f.file, cmd, arg);
622         if (err)
623                 goto out_put;
624 
625         switch (cmd) {
626         case F_GETLK:
627                 err = get_compat_flock(&flock, compat_ptr(arg));
628                 if (err)
629                         break;
630                 err = fcntl_getlk(f.file, convert_fcntl_cmd(cmd), &flock);
631                 if (err)
632                         break;
633                 err = fixup_compat_flock(&flock);
634                 if (err)
635                         return err;
636                 err = put_compat_flock(&flock, compat_ptr(arg));
637                 break;
638         case F_GETLK64:
639         case F_OFD_GETLK:
640                 err = get_compat_flock64(&flock, compat_ptr(arg));
641                 if (err)
642                         break;
643                 err = fcntl_getlk(f.file, convert_fcntl_cmd(cmd), &flock);
644                 if (err)
645                         break;
646                 err = fixup_compat_flock(&flock);
647                 if (err)
648                         return err;
649                 err = put_compat_flock64(&flock, compat_ptr(arg));
650                 break;
651         case F_SETLK:
652         case F_SETLKW:
653                 err = get_compat_flock(&flock, compat_ptr(arg));
654                 if (err)
655                         break;
656                 err = fcntl_setlk(fd, f.file, convert_fcntl_cmd(cmd), &flock);
657                 break;
658         case F_SETLK64:
659         case F_SETLKW64:
660         case F_OFD_SETLK:
661         case F_OFD_SETLKW:
662                 err = get_compat_flock64(&flock, compat_ptr(arg));
663                 if (err)
664                         break;
665                 err = fcntl_setlk(fd, f.file, convert_fcntl_cmd(cmd), &flock);
666                 break;
667         default:
668                 err = do_fcntl(fd, cmd, arg, f.file);
669                 break;
670         }
671 out_put:
672         fdput(f);
673         return err;
674 }
675 
676 COMPAT_SYSCALL_DEFINE3(fcntl, unsigned int, fd, unsigned int, cmd,
677                        compat_ulong_t, arg)
678 {
679         switch (cmd) {
680         case F_GETLK64:
681         case F_SETLK64:
682         case F_SETLKW64:
683         case F_OFD_GETLK:
684         case F_OFD_SETLK:
685         case F_OFD_SETLKW:
686                 return -EINVAL;
687         }
688         return compat_sys_fcntl64(fd, cmd, arg);
689 }
690 #endif
691 
692 /* Table to convert sigio signal codes into poll band bitmaps */
693 
694 static const long band_table[NSIGPOLL] = {
695         POLLIN | POLLRDNORM,                    /* POLL_IN */
696         POLLOUT | POLLWRNORM | POLLWRBAND,      /* POLL_OUT */
697         POLLIN | POLLRDNORM | POLLMSG,          /* POLL_MSG */
698         POLLERR,                                /* POLL_ERR */
699         POLLPRI | POLLRDBAND,                   /* POLL_PRI */
700         POLLHUP | POLLERR                       /* POLL_HUP */
701 };
702 
703 static inline int sigio_perm(struct task_struct *p,
704                              struct fown_struct *fown, int sig)
705 {
706         const struct cred *cred;
707         int ret;
708 
709         rcu_read_lock();
710         cred = __task_cred(p);
711         ret = ((uid_eq(fown->euid, GLOBAL_ROOT_UID) ||
712                 uid_eq(fown->euid, cred->suid) || uid_eq(fown->euid, cred->uid) ||
713                 uid_eq(fown->uid,  cred->suid) || uid_eq(fown->uid,  cred->uid)) &&
714                !security_file_send_sigiotask(p, fown, sig));
715         rcu_read_unlock();
716         return ret;
717 }
718 
719 static void send_sigio_to_task(struct task_struct *p,
720                                struct fown_struct *fown,
721                                int fd, int reason, int group)
722 {
723         /*
724          * F_SETSIG can change ->signum lockless in parallel, make
725          * sure we read it once and use the same value throughout.
726          */
727         int signum = ACCESS_ONCE(fown->signum);
728 
729         if (!sigio_perm(p, fown, signum))
730                 return;
731 
732         switch (signum) {
733                 siginfo_t si;
734                 default:
735                         /* Queue a rt signal with the appropriate fd as its
736                            value.  We use SI_SIGIO as the source, not 
737                            SI_KERNEL, since kernel signals always get 
738                            delivered even if we can't queue.  Failure to
739                            queue in this case _should_ be reported; we fall
740                            back to SIGIO in that case. --sct */
741                         si.si_signo = signum;
742                         si.si_errno = 0;
743                         si.si_code  = reason;
744                         /* Make sure we are called with one of the POLL_*
745                            reasons, otherwise we could leak kernel stack into
746                            userspace.  */
747                         BUG_ON((reason & __SI_MASK) != __SI_POLL);
748                         if (reason - POLL_IN >= NSIGPOLL)
749                                 si.si_band  = ~0L;
750                         else
751                                 si.si_band = band_table[reason - POLL_IN];
752                         si.si_fd    = fd;
753                         if (!do_send_sig_info(signum, &si, p, group))
754                                 break;
755                 /* fall-through: fall back on the old plain SIGIO signal */
756                 case 0:
757                         do_send_sig_info(SIGIO, SEND_SIG_PRIV, p, group);
758         }
759 }
760 
761 void send_sigio(struct fown_struct *fown, int fd, int band)
762 {
763         struct task_struct *p;
764         enum pid_type type;
765         struct pid *pid;
766         int group = 1;
767         
768         read_lock(&fown->lock);
769 
770         type = fown->pid_type;
771         if (type == PIDTYPE_MAX) {
772                 group = 0;
773                 type = PIDTYPE_PID;
774         }
775 
776         pid = fown->pid;
777         if (!pid)
778                 goto out_unlock_fown;
779         
780         read_lock(&tasklist_lock);
781         do_each_pid_task(pid, type, p) {
782                 send_sigio_to_task(p, fown, fd, band, group);
783         } while_each_pid_task(pid, type, p);
784         read_unlock(&tasklist_lock);
785  out_unlock_fown:
786         read_unlock(&fown->lock);
787 }
788 
789 static void send_sigurg_to_task(struct task_struct *p,
790                                 struct fown_struct *fown, int group)
791 {
792         if (sigio_perm(p, fown, SIGURG))
793                 do_send_sig_info(SIGURG, SEND_SIG_PRIV, p, group);
794 }
795 
796 int send_sigurg(struct fown_struct *fown)
797 {
798         struct task_struct *p;
799         enum pid_type type;
800         struct pid *pid;
801         int group = 1;
802         int ret = 0;
803         
804         read_lock(&fown->lock);
805 
806         type = fown->pid_type;
807         if (type == PIDTYPE_MAX) {
808                 group = 0;
809                 type = PIDTYPE_PID;
810         }
811 
812         pid = fown->pid;
813         if (!pid)
814                 goto out_unlock_fown;
815 
816         ret = 1;
817         
818         read_lock(&tasklist_lock);
819         do_each_pid_task(pid, type, p) {
820                 send_sigurg_to_task(p, fown, group);
821         } while_each_pid_task(pid, type, p);
822         read_unlock(&tasklist_lock);
823  out_unlock_fown:
824         read_unlock(&fown->lock);
825         return ret;
826 }
827 
828 static DEFINE_SPINLOCK(fasync_lock);
829 static struct kmem_cache *fasync_cache __read_mostly;
830 
831 static void fasync_free_rcu(struct rcu_head *head)
832 {
833         kmem_cache_free(fasync_cache,
834                         container_of(head, struct fasync_struct, fa_rcu));
835 }
836 
837 /*
838  * Remove a fasync entry. If successfully removed, return
839  * positive and clear the FASYNC flag. If no entry exists,
840  * do nothing and return 0.
841  *
842  * NOTE! It is very important that the FASYNC flag always
843  * match the state "is the filp on a fasync list".
844  *
845  */
846 int fasync_remove_entry(struct file *filp, struct fasync_struct **fapp)
847 {
848         struct fasync_struct *fa, **fp;
849         int result = 0;
850 
851         spin_lock(&filp->f_lock);
852         spin_lock(&fasync_lock);
853         for (fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) {
854                 if (fa->fa_file != filp)
855                         continue;
856 
857                 spin_lock_irq(&fa->fa_lock);
858                 fa->fa_file = NULL;
859                 spin_unlock_irq(&fa->fa_lock);
860 
861                 *fp = fa->fa_next;
862                 call_rcu(&fa->fa_rcu, fasync_free_rcu);
863                 filp->f_flags &= ~FASYNC;
864                 result = 1;
865                 break;
866         }
867         spin_unlock(&fasync_lock);
868         spin_unlock(&filp->f_lock);
869         return result;
870 }
871 
872 struct fasync_struct *fasync_alloc(void)
873 {
874         return kmem_cache_alloc(fasync_cache, GFP_KERNEL);
875 }
876 
877 /*
878  * NOTE! This can be used only for unused fasync entries:
879  * entries that actually got inserted on the fasync list
880  * need to be released by rcu - see fasync_remove_entry.
881  */
882 void fasync_free(struct fasync_struct *new)
883 {
884         kmem_cache_free(fasync_cache, new);
885 }
886 
887 /*
888  * Insert a new entry into the fasync list.  Return the pointer to the
889  * old one if we didn't use the new one.
890  *
891  * NOTE! It is very important that the FASYNC flag always
892  * match the state "is the filp on a fasync list".
893  */
894 struct fasync_struct *fasync_insert_entry(int fd, struct file *filp, struct fasync_struct **fapp, struct fasync_struct *new)
895 {
896         struct fasync_struct *fa, **fp;
897 
898         spin_lock(&filp->f_lock);
899         spin_lock(&fasync_lock);
900         for (fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) {
901                 if (fa->fa_file != filp)
902                         continue;
903 
904                 spin_lock_irq(&fa->fa_lock);
905                 fa->fa_fd = fd;
906                 spin_unlock_irq(&fa->fa_lock);
907                 goto out;
908         }
909 
910         spin_lock_init(&new->fa_lock);
911         new->magic = FASYNC_MAGIC;
912         new->fa_file = filp;
913         new->fa_fd = fd;
914         new->fa_next = *fapp;
915         rcu_assign_pointer(*fapp, new);
916         filp->f_flags |= FASYNC;
917 
918 out:
919         spin_unlock(&fasync_lock);
920         spin_unlock(&filp->f_lock);
921         return fa;
922 }
923 
924 /*
925  * Add a fasync entry. Return negative on error, positive if
926  * added, and zero if did nothing but change an existing one.
927  */
928 static int fasync_add_entry(int fd, struct file *filp, struct fasync_struct **fapp)
929 {
930         struct fasync_struct *new;
931 
932         new = fasync_alloc();
933         if (!new)
934                 return -ENOMEM;
935 
936         /*
937          * fasync_insert_entry() returns the old (update) entry if
938          * it existed.
939          *
940          * So free the (unused) new entry and return 0 to let the
941          * caller know that we didn't add any new fasync entries.
942          */
943         if (fasync_insert_entry(fd, filp, fapp, new)) {
944                 fasync_free(new);
945                 return 0;
946         }
947 
948         return 1;
949 }
950 
951 /*
952  * fasync_helper() is used by almost all character device drivers
953  * to set up the fasync queue, and for regular files by the file
954  * lease code. It returns negative on error, 0 if it did no changes
955  * and positive if it added/deleted the entry.
956  */
957 int fasync_helper(int fd, struct file * filp, int on, struct fasync_struct **fapp)
958 {
959         if (!on)
960                 return fasync_remove_entry(filp, fapp);
961         return fasync_add_entry(fd, filp, fapp);
962 }
963 
964 EXPORT_SYMBOL(fasync_helper);
965 
966 /*
967  * rcu_read_lock() is held
968  */
969 static void kill_fasync_rcu(struct fasync_struct *fa, int sig, int band)
970 {
971         while (fa) {
972                 struct fown_struct *fown;
973                 unsigned long flags;
974 
975                 if (fa->magic != FASYNC_MAGIC) {
976                         printk(KERN_ERR "kill_fasync: bad magic number in "
977                                "fasync_struct!\n");
978                         return;
979                 }
980                 spin_lock_irqsave(&fa->fa_lock, flags);
981                 if (fa->fa_file) {
982                         fown = &fa->fa_file->f_owner;
983                         /* Don't send SIGURG to processes which have not set a
984                            queued signum: SIGURG has its own default signalling
985                            mechanism. */
986                         if (!(sig == SIGURG && fown->signum == 0))
987                                 send_sigio(fown, fa->fa_fd, band);
988                 }
989                 spin_unlock_irqrestore(&fa->fa_lock, flags);
990                 fa = rcu_dereference(fa->fa_next);
991         }
992 }
993 
994 void kill_fasync(struct fasync_struct **fp, int sig, int band)
995 {
996         /* First a quick test without locking: usually
997          * the list is empty.
998          */
999         if (*fp) {
1000                 rcu_read_lock();
1001                 kill_fasync_rcu(rcu_dereference(*fp), sig, band);
1002                 rcu_read_unlock();
1003         }
1004 }
1005 EXPORT_SYMBOL(kill_fasync);
1006 
1007 static int __init fcntl_init(void)
1008 {
1009         /*
1010          * Please add new bits here to ensure allocation uniqueness.
1011          * Exceptions: O_NONBLOCK is a two bit define on parisc; O_NDELAY
1012          * is defined as O_NONBLOCK on some platforms and not on others.
1013          */
1014         BUILD_BUG_ON(21 - 1 /* for O_RDONLY being 0 */ !=
1015                 HWEIGHT32(
1016                         (VALID_OPEN_FLAGS & ~(O_NONBLOCK | O_NDELAY)) |
1017                         __FMODE_EXEC | __FMODE_NONOTIFY));
1018 
1019         fasync_cache = kmem_cache_create("fasync_cache",
1020                 sizeof(struct fasync_struct), 0, SLAB_PANIC, NULL);
1021         return 0;
1022 }
1023 
1024 module_init(fcntl_init)
1025 

~ [ 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