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        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 && 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 &&
  69                        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
 102int __f_setown(struct file *filp, struct pid *pid, enum pid_type type,
 103                int force)
 104{
 105        int err;
 106
 107        err = security_file_set_fowner(filp);
 108        if (err)
 109                return err;
 110
 111        f_modown(filp, pid, type, force);
 112        return 0;
 113}
 114EXPORT_SYMBOL(__f_setown);
 115
 116int f_setown(struct file *filp, unsigned long arg, int force)
 117{
 118        enum pid_type type;
 119        struct pid *pid;
 120        int who = arg;
 121        int result;
 122        type = PIDTYPE_PID;
 123        if (who < 0) {
 124                type = PIDTYPE_PGID;
 125                who = -who;
 126        }
 127        rcu_read_lock();
 128        pid = find_vpid(who);
 129        result = __f_setown(filp, pid, type, force);
 130        rcu_read_unlock();
 131        return result;
 132}
 133EXPORT_SYMBOL(f_setown);
 134
 135void f_delown(struct file *filp)
 136{
 137        f_modown(filp, NULL, PIDTYPE_PID, 1);
 138}
 139
 140pid_t f_getown(struct file *filp)
 141{
 142        pid_t pid;
 143        read_lock(&filp->f_owner.lock);
 144        pid = pid_vnr(filp->f_owner.pid);
 145        if (filp->f_owner.pid_type == PIDTYPE_PGID)
 146                pid = -pid;
 147        read_unlock(&filp->f_owner.lock);
 148        return pid;
 149}
 150
 151static int f_setown_ex(struct file *filp, unsigned long arg)
 152{
 153        struct f_owner_ex __user *owner_p = (void __user *)arg;
 154        struct f_owner_ex owner;
 155        struct pid *pid;
 156        int type;
 157        int ret;
 158
 159        ret = copy_from_user(&owner, owner_p, sizeof(owner));
 160        if (ret)
 161                return -EFAULT;
 162
 163        switch (owner.type) {
 164        case F_OWNER_TID:
 165                type = PIDTYPE_MAX;
 166                break;
 167
 168        case F_OWNER_PID:
 169                type = PIDTYPE_PID;
 170                break;
 171
 172        case F_OWNER_PGRP:
 173                type = PIDTYPE_PGID;
 174                break;
 175
 176        default:
 177                return -EINVAL;
 178        }
 179
 180        rcu_read_lock();
 181        pid = find_vpid(owner.pid);
 182        if (owner.pid && !pid)
 183                ret = -ESRCH;
 184        else
 185                ret = __f_setown(filp, pid, type, 1);
 186        rcu_read_unlock();
 187
 188        return ret;
 189}
 190
 191static int f_getown_ex(struct file *filp, unsigned long arg)
 192{
 193        struct f_owner_ex __user *owner_p = (void __user *)arg;
 194        struct f_owner_ex owner;
 195        int ret = 0;
 196
 197        read_lock(&filp->f_owner.lock);
 198        owner.pid = pid_vnr(filp->f_owner.pid);
 199        switch (filp->f_owner.pid_type) {
 200        case PIDTYPE_MAX:
 201                owner.type = F_OWNER_TID;
 202                break;
 203
 204        case PIDTYPE_PID:
 205                owner.type = F_OWNER_PID;
 206                break;
 207
 208        case PIDTYPE_PGID:
 209                owner.type = F_OWNER_PGRP;
 210                break;
 211
 212        default:
 213                WARN_ON(1);
 214                ret = -EINVAL;
 215                break;
 216        }
 217        read_unlock(&filp->f_owner.lock);
 218
 219        if (!ret) {
 220                ret = copy_to_user(owner_p, &owner, sizeof(owner));
 221                if (ret)
 222                        ret = -EFAULT;
 223        }
 224        return ret;
 225}
 226
 227#ifdef CONFIG_CHECKPOINT_RESTORE
 228static int f_getowner_uids(struct file *filp, unsigned long arg)
 229{
 230        struct user_namespace *user_ns = current_user_ns();
 231        uid_t __user *dst = (void __user *)arg;
 232        uid_t src[2];
 233        int err;
 234
 235        read_lock(&filp->f_owner.lock);
 236        src[0] = from_kuid(user_ns, filp->f_owner.uid);
 237        src[1] = from_kuid(user_ns, filp->f_owner.euid);
 238        read_unlock(&filp->f_owner.lock);
 239
 240        err  = put_user(src[0], &dst[0]);
 241        err |= put_user(src[1], &dst[1]);
 242
 243        return err;
 244}
 245#else
 246static int f_getowner_uids(struct file *filp, unsigned long arg)
 247{
 248        return -EINVAL;
 249}
 250#endif
 251
 252static long do_fcntl(int fd, unsigned int cmd, unsigned long arg,
 253                struct file *filp)
 254{
 255        void __user *argp = (void __user *)arg;
 256        struct flock flock;
 257        long err = -EINVAL;
 258
 259        switch (cmd) {
 260        case F_DUPFD:
 261                err = f_dupfd(arg, filp, 0);
 262                break;
 263        case F_DUPFD_CLOEXEC:
 264                err = f_dupfd(arg, filp, O_CLOEXEC);
 265                break;
 266        case F_GETFD:
 267                err = get_close_on_exec(fd) ? FD_CLOEXEC : 0;
 268                break;
 269        case F_SETFD:
 270                err = 0;
 271                set_close_on_exec(fd, arg & FD_CLOEXEC);
 272                break;
 273        case F_GETFL:
 274                err = filp->f_flags;
 275                break;
 276        case F_SETFL:
 277                err = setfl(fd, filp, arg);
 278                break;
 279#if BITS_PER_LONG != 32
 280        /* 32-bit arches must use fcntl64() */
 281        case F_OFD_GETLK:
 282#endif
 283        case F_GETLK:
 284                if (copy_from_user(&flock, argp, sizeof(flock)))
 285                        return -EFAULT;
 286                err = fcntl_getlk(filp, cmd, &flock);
 287                if (!err && copy_to_user(argp, &flock, sizeof(flock)))
 288                        return -EFAULT;
 289                break;
 290#if BITS_PER_LONG != 32
 291        /* 32-bit arches must use fcntl64() */
 292        case F_OFD_SETLK:
 293        case F_OFD_SETLKW:
 294#endif
 295                /* Fallthrough */
 296        case F_SETLK:
 297        case F_SETLKW:
 298                if (copy_from_user(&flock, argp, sizeof(flock)))
 299                        return -EFAULT;
 300                err = fcntl_setlk(fd, filp, cmd, &flock);
 301                break;
 302        case F_GETOWN:
 303                /*
 304                 * XXX If f_owner is a process group, the
 305                 * negative return value will get converted
 306                 * into an error.  Oops.  If we keep the
 307                 * current syscall conventions, the only way
 308                 * to fix this will be in libc.
 309                 */
 310                err = f_getown(filp);
 311                force_successful_syscall_return();
 312                break;
 313        case F_SETOWN:
 314                err = f_setown(filp, arg, 1);
 315                break;
 316        case F_GETOWN_EX:
 317                err = f_getown_ex(filp, arg);
 318                break;
 319        case F_SETOWN_EX:
 320                err = f_setown_ex(filp, arg);
 321                break;
 322        case F_GETOWNER_UIDS:
 323                err = f_getowner_uids(filp, arg);
 324                break;
 325        case F_GETSIG:
 326                err = filp->f_owner.signum;
 327                break;
 328        case F_SETSIG:
 329                /* arg == 0 restores default behaviour. */
 330                if (!valid_signal(arg)) {
 331                        break;
 332                }
 333                err = 0;
 334                filp->f_owner.signum = arg;
 335                break;
 336        case F_GETLEASE:
 337                err = fcntl_getlease(filp);
 338                break;
 339        case F_SETLEASE:
 340                err = fcntl_setlease(fd, filp, arg);
 341                break;
 342        case F_NOTIFY:
 343                err = fcntl_dirnotify(fd, filp, arg);
 344                break;
 345        case F_SETPIPE_SZ:
 346        case F_GETPIPE_SZ:
 347                err = pipe_fcntl(filp, cmd, arg);
 348                break;
 349        case F_ADD_SEALS:
 350        case F_GET_SEALS:
 351                err = shmem_fcntl(filp, cmd, arg);
 352                break;
 353        default:
 354                break;
 355        }
 356        return err;
 357}
 358
 359static int check_fcntl_cmd(unsigned cmd)
 360{
 361        switch (cmd) {
 362        case F_DUPFD:
 363        case F_DUPFD_CLOEXEC:
 364        case F_GETFD:
 365        case F_SETFD:
 366        case F_GETFL:
 367                return 1;
 368        }
 369        return 0;
 370}
 371
 372SYSCALL_DEFINE3(fcntl, unsigned int, fd, unsigned int, cmd, unsigned long, arg)
 373{       
 374        struct fd f = fdget_raw(fd);
 375        long err = -EBADF;
 376
 377        if (!f.file)
 378                goto out;
 379
 380        if (unlikely(f.file->f_mode & FMODE_PATH)) {
 381                if (!check_fcntl_cmd(cmd))
 382                        goto out1;
 383        }
 384
 385        err = security_file_fcntl(f.file, cmd, arg);
 386        if (!err)
 387                err = do_fcntl(fd, cmd, arg, f.file);
 388
 389out1:
 390        fdput(f);
 391out:
 392        return err;
 393}
 394
 395#if BITS_PER_LONG == 32
 396SYSCALL_DEFINE3(fcntl64, unsigned int, fd, unsigned int, cmd,
 397                unsigned long, arg)
 398{       
 399        void __user *argp = (void __user *)arg;
 400        struct fd f = fdget_raw(fd);
 401        struct flock64 flock;
 402        long err = -EBADF;
 403
 404        if (!f.file)
 405                goto out;
 406
 407        if (unlikely(f.file->f_mode & FMODE_PATH)) {
 408                if (!check_fcntl_cmd(cmd))
 409                        goto out1;
 410        }
 411
 412        err = security_file_fcntl(f.file, cmd, arg);
 413        if (err)
 414                goto out1;
 415        
 416        switch (cmd) {
 417        case F_GETLK64:
 418        case F_OFD_GETLK:
 419                err = -EFAULT;
 420                if (copy_from_user(&flock, argp, sizeof(flock)))
 421                        break;
 422                err = fcntl_getlk64(f.file, cmd, &flock);
 423                if (!err && copy_to_user(argp, &flock, sizeof(flock)))
 424                        err = -EFAULT;
 425                break;
 426        case F_SETLK64:
 427        case F_SETLKW64:
 428        case F_OFD_SETLK:
 429        case F_OFD_SETLKW:
 430                err = -EFAULT;
 431                if (copy_from_user(&flock, argp, sizeof(flock)))
 432                        break;
 433                err = fcntl_setlk64(fd, f.file, cmd, &flock);
 434                break;
 435        default:
 436                err = do_fcntl(fd, cmd, arg, f.file);
 437                break;
 438        }
 439out1:
 440        fdput(f);
 441out:
 442        return err;
 443}
 444#endif
 445
 446/* Table to convert sigio signal codes into poll band bitmaps */
 447
 448static const long band_table[NSIGPOLL] = {
 449        POLLIN | POLLRDNORM,                    /* POLL_IN */
 450        POLLOUT | POLLWRNORM | POLLWRBAND,      /* POLL_OUT */
 451        POLLIN | POLLRDNORM | POLLMSG,          /* POLL_MSG */
 452        POLLERR,                                /* POLL_ERR */
 453        POLLPRI | POLLRDBAND,                   /* POLL_PRI */
 454        POLLHUP | POLLERR                       /* POLL_HUP */
 455};
 456
 457static inline int sigio_perm(struct task_struct *p,
 458                             struct fown_struct *fown, int sig)
 459{
 460        const struct cred *cred;
 461        int ret;
 462
 463        rcu_read_lock();
 464        cred = __task_cred(p);
 465        ret = ((uid_eq(fown->euid, GLOBAL_ROOT_UID) ||
 466                uid_eq(fown->euid, cred->suid) || uid_eq(fown->euid, cred->uid) ||
 467                uid_eq(fown->uid,  cred->suid) || uid_eq(fown->uid,  cred->uid)) &&
 468               !security_file_send_sigiotask(p, fown, sig));
 469        rcu_read_unlock();
 470        return ret;
 471}
 472
 473static void send_sigio_to_task(struct task_struct *p,
 474                               struct fown_struct *fown,
 475                               int fd, int reason, int group)
 476{
 477        /*
 478         * F_SETSIG can change ->signum lockless in parallel, make
 479         * sure we read it once and use the same value throughout.
 480         */
 481        int signum = ACCESS_ONCE(fown->signum);
 482
 483        if (!sigio_perm(p, fown, signum))
 484                return;
 485
 486        switch (signum) {
 487                siginfo_t si;
 488                default:
 489                        /* Queue a rt signal with the appropriate fd as its
 490                           value.  We use SI_SIGIO as the source, not 
 491                           SI_KERNEL, since kernel signals always get 
 492                           delivered even if we can't queue.  Failure to
 493                           queue in this case _should_ be reported; we fall
 494                           back to SIGIO in that case. --sct */
 495                        si.si_signo = signum;
 496                        si.si_errno = 0;
 497                        si.si_code  = reason;
 498                        /* Make sure we are called with one of the POLL_*
 499                           reasons, otherwise we could leak kernel stack into
 500                           userspace.  */
 501                        BUG_ON((reason & __SI_MASK) != __SI_POLL);
 502                        if (reason - POLL_IN >= NSIGPOLL)
 503                                si.si_band  = ~0L;
 504                        else
 505                                si.si_band = band_table[reason - POLL_IN];
 506                        si.si_fd    = fd;
 507                        if (!do_send_sig_info(signum, &si, p, group))
 508                                break;
 509                /* fall-through: fall back on the old plain SIGIO signal */
 510                case 0:
 511                        do_send_sig_info(SIGIO, SEND_SIG_PRIV, p, group);
 512        }
 513}
 514
 515void send_sigio(struct fown_struct *fown, int fd, int band)
 516{
 517        struct task_struct *p;
 518        enum pid_type type;
 519        struct pid *pid;
 520        int group = 1;
 521        
 522        read_lock(&fown->lock);
 523
 524        type = fown->pid_type;
 525        if (type == PIDTYPE_MAX) {
 526                group = 0;
 527                type = PIDTYPE_PID;
 528        }
 529
 530        pid = fown->pid;
 531        if (!pid)
 532                goto out_unlock_fown;
 533        
 534        qread_lock(&tasklist_lock);
 535        do_each_pid_task(pid, type, p) {
 536                send_sigio_to_task(p, fown, fd, band, group);
 537        } while_each_pid_task(pid, type, p);
 538        qread_unlock(&tasklist_lock);
 539 out_unlock_fown:
 540        read_unlock(&fown->lock);
 541}
 542
 543static void send_sigurg_to_task(struct task_struct *p,
 544                                struct fown_struct *fown, int group)
 545{
 546        if (sigio_perm(p, fown, SIGURG))
 547                do_send_sig_info(SIGURG, SEND_SIG_PRIV, p, group);
 548}
 549
 550int send_sigurg(struct fown_struct *fown)
 551{
 552        struct task_struct *p;
 553        enum pid_type type;
 554        struct pid *pid;
 555        int group = 1;
 556        int ret = 0;
 557        
 558        read_lock(&fown->lock);
 559
 560        type = fown->pid_type;
 561        if (type == PIDTYPE_MAX) {
 562                group = 0;
 563                type = PIDTYPE_PID;
 564        }
 565
 566        pid = fown->pid;
 567        if (!pid)
 568                goto out_unlock_fown;
 569
 570        ret = 1;
 571        
 572        qread_lock(&tasklist_lock);
 573        do_each_pid_task(pid, type, p) {
 574                send_sigurg_to_task(p, fown, group);
 575        } while_each_pid_task(pid, type, p);
 576        qread_unlock(&tasklist_lock);
 577 out_unlock_fown:
 578        read_unlock(&fown->lock);
 579        return ret;
 580}
 581
 582static DEFINE_SPINLOCK(fasync_lock);
 583static struct kmem_cache *fasync_cache __read_mostly;
 584
 585static void fasync_free_rcu(struct rcu_head *head)
 586{
 587        kmem_cache_free(fasync_cache,
 588                        container_of(head, struct fasync_struct, fa_rcu));
 589}
 590
 591/*
 592 * Remove a fasync entry. If successfully removed, return
 593 * positive and clear the FASYNC flag. If no entry exists,
 594 * do nothing and return 0.
 595 *
 596 * NOTE! It is very important that the FASYNC flag always
 597 * match the state "is the filp on a fasync list".
 598 *
 599 */
 600int fasync_remove_entry(struct file *filp, struct fasync_struct **fapp)
 601{
 602        struct fasync_struct *fa, **fp;
 603        int result = 0;
 604
 605        spin_lock(&filp->f_lock);
 606        spin_lock(&fasync_lock);
 607        for (fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) {
 608                if (fa->fa_file != filp)
 609                        continue;
 610
 611                spin_lock_irq(&fa->fa_lock);
 612                fa->fa_file = NULL;
 613                spin_unlock_irq(&fa->fa_lock);
 614
 615                *fp = fa->fa_next;
 616                call_rcu(&fa->fa_rcu, fasync_free_rcu);
 617                filp->f_flags &= ~FASYNC;
 618                result = 1;
 619                break;
 620        }
 621        spin_unlock(&fasync_lock);
 622        spin_unlock(&filp->f_lock);
 623        return result;
 624}
 625
 626struct fasync_struct *fasync_alloc(void)
 627{
 628        return kmem_cache_alloc(fasync_cache, GFP_KERNEL);
 629}
 630
 631/*
 632 * NOTE! This can be used only for unused fasync entries:
 633 * entries that actually got inserted on the fasync list
 634 * need to be released by rcu - see fasync_remove_entry.
 635 */
 636void fasync_free(struct fasync_struct *new)
 637{
 638        kmem_cache_free(fasync_cache, new);
 639}
 640
 641/*
 642 * Insert a new entry into the fasync list.  Return the pointer to the
 643 * old one if we didn't use the new one.
 644 *
 645 * NOTE! It is very important that the FASYNC flag always
 646 * match the state "is the filp on a fasync list".
 647 */
 648struct fasync_struct *fasync_insert_entry(int fd, struct file *filp, struct fasync_struct **fapp, struct fasync_struct *new)
 649{
 650        struct fasync_struct *fa, **fp;
 651
 652        spin_lock(&filp->f_lock);
 653        spin_lock(&fasync_lock);
 654        for (fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) {
 655                if (fa->fa_file != filp)
 656                        continue;
 657
 658                spin_lock_irq(&fa->fa_lock);
 659                fa->fa_fd = fd;
 660                spin_unlock_irq(&fa->fa_lock);
 661                goto out;
 662        }
 663
 664        spin_lock_init(&new->fa_lock);
 665        new->magic = FASYNC_MAGIC;
 666        new->fa_file = filp;
 667        new->fa_fd = fd;
 668        new->fa_next = *fapp;
 669        rcu_assign_pointer(*fapp, new);
 670        filp->f_flags |= FASYNC;
 671
 672out:
 673        spin_unlock(&fasync_lock);
 674        spin_unlock(&filp->f_lock);
 675        return fa;
 676}
 677
 678/*
 679 * Add a fasync entry. Return negative on error, positive if
 680 * added, and zero if did nothing but change an existing one.
 681 */
 682static int fasync_add_entry(int fd, struct file *filp, struct fasync_struct **fapp)
 683{
 684        struct fasync_struct *new;
 685
 686        new = fasync_alloc();
 687        if (!new)
 688                return -ENOMEM;
 689
 690        /*
 691         * fasync_insert_entry() returns the old (update) entry if
 692         * it existed.
 693         *
 694         * So free the (unused) new entry and return 0 to let the
 695         * caller know that we didn't add any new fasync entries.
 696         */
 697        if (fasync_insert_entry(fd, filp, fapp, new)) {
 698                fasync_free(new);
 699                return 0;
 700        }
 701
 702        return 1;
 703}
 704
 705/*
 706 * fasync_helper() is used by almost all character device drivers
 707 * to set up the fasync queue, and for regular files by the file
 708 * lease code. It returns negative on error, 0 if it did no changes
 709 * and positive if it added/deleted the entry.
 710 */
 711int fasync_helper(int fd, struct file * filp, int on, struct fasync_struct **fapp)
 712{
 713        if (!on)
 714                return fasync_remove_entry(filp, fapp);
 715        return fasync_add_entry(fd, filp, fapp);
 716}
 717
 718EXPORT_SYMBOL(fasync_helper);
 719
 720/*
 721 * rcu_read_lock() is held
 722 */
 723static void kill_fasync_rcu(struct fasync_struct *fa, int sig, int band)
 724{
 725        while (fa) {
 726                struct fown_struct *fown;
 727                unsigned long flags;
 728
 729                if (fa->magic != FASYNC_MAGIC) {
 730                        printk(KERN_ERR "kill_fasync: bad magic number in "
 731                               "fasync_struct!\n");
 732                        return;
 733                }
 734                spin_lock_irqsave(&fa->fa_lock, flags);
 735                if (fa->fa_file) {
 736                        fown = &fa->fa_file->f_owner;
 737                        /* Don't send SIGURG to processes which have not set a
 738                           queued signum: SIGURG has its own default signalling
 739                           mechanism. */
 740                        if (!(sig == SIGURG && fown->signum == 0))
 741                                send_sigio(fown, fa->fa_fd, band);
 742                }
 743                spin_unlock_irqrestore(&fa->fa_lock, flags);
 744                fa = rcu_dereference(fa->fa_next);
 745        }
 746}
 747
 748void kill_fasync(struct fasync_struct **fp, int sig, int band)
 749{
 750        /* First a quick test without locking: usually
 751         * the list is empty.
 752         */
 753        if (*fp) {
 754                rcu_read_lock();
 755                kill_fasync_rcu(rcu_dereference(*fp), sig, band);
 756                rcu_read_unlock();
 757        }
 758}
 759EXPORT_SYMBOL(kill_fasync);
 760
 761static int __init fcntl_init(void)
 762{
 763        /*
 764         * Please add new bits here to ensure allocation uniqueness.
 765         * Exceptions: O_NONBLOCK is a two bit define on parisc; O_NDELAY
 766         * is defined as O_NONBLOCK on some platforms and not on others.
 767         */
 768        BUILD_BUG_ON(19 - 1 /* for O_RDONLY being 0 */ != HWEIGHT32(
 769                O_RDONLY        | O_WRONLY      | O_RDWR        |
 770                O_CREAT         | O_EXCL        | O_NOCTTY      |
 771                O_TRUNC         | O_APPEND      | /* O_NONBLOCK | */
 772                __O_SYNC        | O_DSYNC       | FASYNC        |
 773                O_DIRECT        | O_LARGEFILE   | O_DIRECTORY   |
 774                O_NOFOLLOW      | O_NOATIME     | O_CLOEXEC     |
 775                __FMODE_EXEC    | O_PATH
 776                ));
 777
 778        fasync_cache = kmem_cache_create("fasync_cache",
 779                sizeof(struct fasync_struct), 0, SLAB_PANIC, NULL);
 780        return 0;
 781}
 782
 783module_init(fcntl_init)
 784