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