fs/fcntl.c

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