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 24#include <asm/poll.h> 25#include <asm/siginfo.h> 26#include <asm/uaccess.h> 27 28void set_close_on_exec(unsigned int fd, int flag) 29{ 30 struct files_struct *files = current->files; 31 struct fdtable *fdt; 32 spin_lock(&files->file_lock); 33 fdt = files_fdtable(files); 34 if (flag) 35 FD_SET(fd, fdt->close_on_exec); 36 else 37 FD_CLR(fd, fdt->close_on_exec); 38 spin_unlock(&files->file_lock); 39} 40 41static int get_close_on_exec(unsigned int fd) 42{ 43 struct files_struct *files = current->files; 44 struct fdtable *fdt; 45 int res; 46 rcu_read_lock(); 47 fdt = files_fdtable(files); 48 res = FD_ISSET(fd, fdt->close_on_exec); 49 rcu_read_unlock(); 50 return res; 51} 52 53SYSCALL_DEFINE3(dup3, unsigned int, oldfd, unsigned int, newfd, int, flags) 54{ 55 int err = -EBADF; 56 struct file * file, *tofree; 57 struct files_struct * files = current->files; 58 struct fdtable *fdt; 59 60 if ((flags & ~O_CLOEXEC) != 0) 61 return -EINVAL; 62 63 if (unlikely(oldfd == newfd)) 64 return -EINVAL; 65 66 spin_lock(&files->file_lock); 67 err = expand_files(files, newfd); 68 file = fcheck(oldfd); 69 if (unlikely(!file)) 70 goto Ebadf; 71 if (unlikely(err < 0)) { 72 if (err == -EMFILE) 73 goto Ebadf; 74 goto out_unlock; 75 } 76 /* 77 * We need to detect attempts to do dup2() over allocated but still 78 * not finished descriptor. NB: OpenBSD avoids that at the price of 79 * extra work in their equivalent of fget() - they insert struct 80 * file immediately after grabbing descriptor, mark it larval if 81 * more work (e.g. actual opening) is needed and make sure that 82 * fget() treats larval files as absent. Potentially interesting, 83 * but while extra work in fget() is trivial, locking implications 84 * and amount of surgery on open()-related paths in VFS are not. 85 * FreeBSD fails with -EBADF in the same situation, NetBSD "solution" 86 * deadlocks in rather amusing ways, AFAICS. All of that is out of 87 * scope of POSIX or SUS, since neither considers shared descriptor 88 * tables and this condition does not arise without those. 89 */ 90 err = -EBUSY; 91 fdt = files_fdtable(files); 92 tofree = fdt->fd[newfd]; 93 if (!tofree && FD_ISSET(newfd, fdt->open_fds)) 94 goto out_unlock; 95 get_file(file); 96 rcu_assign_pointer(fdt->fd[newfd], file); 97 FD_SET(newfd, fdt->open_fds); 98 if (flags & O_CLOEXEC) 99 FD_SET(newfd, fdt->close_on_exec); 100 else 101 FD_CLR(newfd, fdt->close_on_exec); 102 spin_unlock(&files->file_lock); 103 104 if (tofree) 105 filp_close(tofree, files); 106 107 return newfd; 108 109Ebadf: 110 err = -EBADF; 111out_unlock: 112 spin_unlock(&files->file_lock); 113 return err; 114} 115 116SYSCALL_DEFINE2(dup2, unsigned int, oldfd, unsigned int, newfd) 117{ 118 if (unlikely(newfd == oldfd)) { /* corner case */ 119 struct files_struct *files = current->files; 120 int retval = oldfd; 121 122 rcu_read_lock(); 123 if (!fcheck_files(files, oldfd)) 124 retval = -EBADF; 125 rcu_read_unlock(); 126 return retval; 127 } 128 return sys_dup3(oldfd, newfd, 0); 129} 130 131SYSCALL_DEFINE1(dup, unsigned int, fildes) 132{ 133 int ret = -EBADF; 134 struct file *file = fget(fildes); 135 136 if (file) { 137 ret = get_unused_fd(); 138 if (ret >= 0) 139 fd_install(ret, file); 140 else 141 fput(file); 142 } 143 return ret; 144} 145 146#define SETFL_MASK (O_APPEND | O_NONBLOCK | O_NDELAY | O_DIRECT | O_NOATIME) 147 148static int setfl(int fd, struct file * filp, unsigned long arg) 149{ 150 struct inode * inode = filp->f_path.dentry->d_inode; 151 int error = 0; 152 153 /* 154 * O_APPEND cannot be cleared if the file is marked as append-only 155 * and the file is open for write. 156 */ 157 if (((arg ^ filp->f_flags) & O_APPEND) && IS_APPEND(inode)) 158 return -EPERM; 159 160 /* O_NOATIME can only be set by the owner or superuser */ 161 if ((arg & O_NOATIME) && !(filp->f_flags & O_NOATIME)) 162 if (!is_owner_or_cap(inode)) 163 return -EPERM; 164 165 /* required for strict SunOS emulation */ 166 if (O_NONBLOCK != O_NDELAY) 167 if (arg & O_NDELAY) 168 arg |= O_NONBLOCK; 169 170 if (arg & O_DIRECT) { 171 if (!filp->f_mapping || !filp->f_mapping->a_ops || 172 !filp->f_mapping->a_ops->direct_IO) 173 return -EINVAL; 174 } 175 176 if (filp->f_op && filp->f_op->check_flags) 177 error = filp->f_op->check_flags(arg); 178 if (error) 179 return error; 180 181 /* 182 * ->fasync() is responsible for setting the FASYNC bit. 183 */ 184 if (((arg ^ filp->f_flags) & FASYNC) && filp->f_op && 185 filp->f_op->fasync) { 186 error = filp->f_op->fasync(fd, filp, (arg & FASYNC) != 0); 187 if (error < 0) 188 goto out; 189 if (error > 0) 190 error = 0; 191 } 192 spin_lock(&filp->f_lock); 193 filp->f_flags = (arg & SETFL_MASK) | (filp->f_flags & ~SETFL_MASK); 194 spin_unlock(&filp->f_lock); 195 196 out: 197 return error; 198} 199 200static void f_modown(struct file *filp, struct pid *pid, enum pid_type type, 201 int force) 202{ 203 write_lock_irq(&filp->f_owner.lock); 204 if (force || !filp->f_owner.pid) { 205 put_pid(filp->f_owner.pid); 206 filp->f_owner.pid = get_pid(pid); 207 filp->f_owner.pid_type = type; 208 209 if (pid) { 210 const struct cred *cred = current_cred(); 211 filp->f_owner.uid = cred->uid; 212 filp->f_owner.euid = cred->euid; 213 } 214 } 215 write_unlock_irq(&filp->f_owner.lock); 216} 217 218int __f_setown(struct file *filp, struct pid *pid, enum pid_type type, 219 int force) 220{ 221 int err; 222 223 err = security_file_set_fowner(filp); 224 if (err) 225 return err; 226 227 f_modown(filp, pid, type, force); 228 return 0; 229} 230EXPORT_SYMBOL(__f_setown); 231 232int f_setown(struct file *filp, unsigned long arg, int force) 233{ 234 enum pid_type type; 235 struct pid *pid; 236 int who = arg; 237 int result; 238 type = PIDTYPE_PID; 239 if (who < 0) { 240 type = PIDTYPE_PGID; 241 who = -who; 242 } 243 rcu_read_lock(); 244 pid = find_vpid(who); 245 result = __f_setown(filp, pid, type, force); 246 rcu_read_unlock(); 247 return result; 248} 249EXPORT_SYMBOL(f_setown); 250 251void f_delown(struct file *filp) 252{ 253 f_modown(filp, NULL, PIDTYPE_PID, 1); 254} 255 256pid_t f_getown(struct file *filp) 257{ 258 pid_t pid; 259 read_lock(&filp->f_owner.lock); 260 pid = pid_vnr(filp->f_owner.pid); 261 if (filp->f_owner.pid_type == PIDTYPE_PGID) 262 pid = -pid; 263 read_unlock(&filp->f_owner.lock); 264 return pid; 265} 266 267static int f_setown_ex(struct file *filp, unsigned long arg) 268{ 269 struct f_owner_ex * __user owner_p = (void * __user)arg; 270 struct f_owner_ex owner; 271 struct pid *pid; 272 int type; 273 int ret; 274 275 ret = copy_from_user(&owner, owner_p, sizeof(owner)); 276 if (ret) 277 return -EFAULT; 278 279 switch (owner.type) { 280 case F_OWNER_TID: 281 type = PIDTYPE_MAX; 282 break; 283 284 case F_OWNER_PID: 285 type = PIDTYPE_PID; 286 break; 287 288 case F_OWNER_PGRP: 289 type = PIDTYPE_PGID; 290 break; 291 292 default: 293 return -EINVAL; 294 } 295 296 rcu_read_lock(); 297 pid = find_vpid(owner.pid); 298 if (owner.pid && !pid) 299 ret = -ESRCH; 300 else 301 ret = __f_setown(filp, pid, type, 1); 302 rcu_read_unlock(); 303 304 return ret; 305} 306 307static int f_getown_ex(struct file *filp, unsigned long arg) 308{ 309 struct f_owner_ex * __user owner_p = (void * __user)arg; 310 struct f_owner_ex owner; 311 int ret = 0; 312 313 read_lock(&filp->f_owner.lock); 314 owner.pid = pid_vnr(filp->f_owner.pid); 315 switch (filp->f_owner.pid_type) { 316 case PIDTYPE_MAX: 317 owner.type = F_OWNER_TID; 318 break; 319 320 case PIDTYPE_PID: 321 owner.type = F_OWNER_PID; 322 break; 323 324 case PIDTYPE_PGID: 325 owner.type = F_OWNER_PGRP; 326 break; 327 328 default: 329 WARN_ON(1); 330 ret = -EINVAL; 331 break; 332 } 333 read_unlock(&filp->f_owner.lock); 334 335 if (!ret) { 336 ret = copy_to_user(owner_p, &owner, sizeof(owner)); 337 if (ret) 338 ret = -EFAULT; 339 } 340 return ret; 341} 342 343static long do_fcntl(int fd, unsigned int cmd, unsigned long arg, 344 struct file *filp) 345{ 346 long err = -EINVAL; 347 348 switch (cmd) { 349 case F_DUPFD: 350 case F_DUPFD_CLOEXEC: 351 if (arg >= rlimit(RLIMIT_NOFILE)) 352 break; 353 err = alloc_fd(arg, cmd == F_DUPFD_CLOEXEC ? O_CLOEXEC : 0); 354 if (err >= 0) { 355 get_file(filp); 356 fd_install(err, filp); 357 } 358 break; 359 case F_GETFD: 360 err = get_close_on_exec(fd) ? FD_CLOEXEC : 0; 361 break; 362 case F_SETFD: 363 err = 0; 364 set_close_on_exec(fd, arg & FD_CLOEXEC); 365 break; 366 case F_GETFL: 367 err = filp->f_flags; 368 break; 369 case F_SETFL: 370 err = setfl(fd, filp, arg); 371 break; 372 case F_GETLK: 373 err = fcntl_getlk(filp, (struct flock __user *) arg); 374 break; 375 case F_SETLK: 376 case F_SETLKW: 377 err = fcntl_setlk(fd, filp, cmd, (struct flock __user *) arg); 378 break; 379 case F_GETOWN: 380 err = f_getown(filp); 381 force_successful_syscall_return(); 382 break; 383 case F_SETOWN: 384 err = f_setown(filp, arg, 1); 385 break; 386 case F_GETOWN_EX: 387 err = f_getown_ex(filp, arg); 388 break; 389 case F_SETOWN_EX: 390 err = f_setown_ex(filp, arg); 391 break; 392 case F_GETSIG: 393 err = filp->f_owner.signum; 394 break; 395 case F_SETSIG: 396 /* arg == 0 restores default behaviour. */ 397 if (!valid_signal(arg)) { 398 break; 399 } 400 err = 0; 401 filp->f_owner.signum = arg; 402 break; 403 case F_GETLEASE: 404 err = fcntl_getlease(filp); 405 break; 406 case F_SETLEASE: 407 err = fcntl_setlease(fd, filp, arg); 408 break; 409 case F_NOTIFY: 410 err = fcntl_dirnotify(fd, filp, arg); 411 break; 412 case F_SETPIPE_SZ: 413 case F_GETPIPE_SZ: 414 err = pipe_fcntl(filp, cmd, arg); 415 break; 416 default: 417 break; 418 } 419 return err; 420} 421 422SYSCALL_DEFINE3(fcntl, unsigned int, fd, unsigned int, cmd, unsigned long, arg) 423{ 424 struct file *filp; 425 long err = -EBADF; 426 427 filp = fget(fd); 428 if (!filp) 429 goto out; 430 431 err = security_file_fcntl(filp, cmd, arg); 432 if (err) { 433 fput(filp); 434 return err; 435 } 436 437 err = do_fcntl(fd, cmd, arg, filp); 438 439 fput(filp); 440out: 441 return err; 442} 443 444#if BITS_PER_LONG == 32 445SYSCALL_DEFINE3(fcntl64, unsigned int, fd, unsigned int, cmd, 446 unsigned long, arg) 447{ 448 struct file * filp; 449 long err; 450 451 err = -EBADF; 452 filp = fget(fd); 453 if (!filp) 454 goto out; 455 456 err = security_file_fcntl(filp, cmd, arg); 457 if (err) { 458 fput(filp); 459 return err; 460 } 461 err = -EBADF; 462 463 switch (cmd) { 464 case F_GETLK64: 465 err = fcntl_getlk64(filp, (struct flock64 __user *) arg); 466 break; 467 case F_SETLK64: 468 case F_SETLKW64: 469 err = fcntl_setlk64(fd, filp, cmd, 470 (struct flock64 __user *) arg); 471 break; 472 default: 473 err = do_fcntl(fd, cmd, arg, filp); 474 break; 475 } 476 fput(filp); 477out: 478 return err; 479} 480#endif 481 482/* Table to convert sigio signal codes into poll band bitmaps */ 483 484static const long band_table[NSIGPOLL] = { 485 POLLIN | POLLRDNORM, /* POLL_IN */ 486 POLLOUT | POLLWRNORM | POLLWRBAND, /* POLL_OUT */ 487 POLLIN | POLLRDNORM | POLLMSG, /* POLL_MSG */ 488 POLLERR, /* POLL_ERR */ 489 POLLPRI | POLLRDBAND, /* POLL_PRI */ 490 POLLHUP | POLLERR /* POLL_HUP */ 491}; 492 493static inline int sigio_perm(struct task_struct *p, 494 struct fown_struct *fown, int sig) 495{ 496 const struct cred *cred; 497 int ret; 498 499 rcu_read_lock(); 500 cred = __task_cred(p); 501 ret = ((fown->euid == 0 || 502 fown->euid == cred->suid || fown->euid == cred->uid || 503 fown->uid == cred->suid || fown->uid == cred->uid) && 504 !security_file_send_sigiotask(p, fown, sig)); 505 rcu_read_unlock(); 506 return ret; 507} 508 509static void send_sigio_to_task(struct task_struct *p, 510 struct fown_struct *fown, 511 int fd, int reason, int group) 512{ 513 /* 514 * F_SETSIG can change ->signum lockless in parallel, make 515 * sure we read it once and use the same value throughout. 516 */ 517 int signum = ACCESS_ONCE(fown->signum); 518 519 if (!sigio_perm(p, fown, signum)) 520 return; 521 522 switch (signum) { 523 siginfo_t si; 524 default: 525 /* Queue a rt signal with the appropriate fd as its 526 value. We use SI_SIGIO as the source, not 527 SI_KERNEL, since kernel signals always get 528 delivered even if we can't queue. Failure to 529 queue in this case _should_ be reported; we fall 530 back to SIGIO in that case. --sct */ 531 si.si_signo = signum; 532 si.si_errno = 0; 533 si.si_code = reason; 534 /* Make sure we are called with one of the POLL_* 535 reasons, otherwise we could leak kernel stack into 536 userspace. */ 537 BUG_ON((reason & __SI_MASK) != __SI_POLL); 538 if (reason - POLL_IN >= NSIGPOLL) 539 si.si_band = ~0L; 540 else 541 si.si_band = band_table[reason - POLL_IN]; 542 si.si_fd = fd; 543 if (!do_send_sig_info(signum, &si, p, group)) 544 break; 545 /* fall-through: fall back on the old plain SIGIO signal */ 546 case 0: 547 do_send_sig_info(SIGIO, SEND_SIG_PRIV, p, group); 548 } 549} 550 551void send_sigio(struct fown_struct *fown, int fd, int band) 552{ 553 struct task_struct *p; 554 enum pid_type type; 555 struct pid *pid; 556 int group = 1; 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 read_lock(&tasklist_lock); 571 do_each_pid_task(pid, type, p) { 572 send_sigio_to_task(p, fown, fd, band, group); 573 } while_each_pid_task(pid, type, p); 574 read_unlock(&tasklist_lock); 575 out_unlock_fown: 576 read_unlock(&fown->lock); 577} 578 579static void send_sigurg_to_task(struct task_struct *p, 580 struct fown_struct *fown, int group) 581{ 582 if (sigio_perm(p, fown, SIGURG)) 583 do_send_sig_info(SIGURG, SEND_SIG_PRIV, p, group); 584} 585 586int send_sigurg(struct fown_struct *fown) 587{ 588 struct task_struct *p; 589 enum pid_type type; 590 struct pid *pid; 591 int group = 1; 592 int ret = 0; 593 594 read_lock(&fown->lock); 595 596 type = fown->pid_type; 597 if (type == PIDTYPE_MAX) { 598 group = 0; 599 type = PIDTYPE_PID; 600 } 601 602 pid = fown->pid; 603 if (!pid) 604 goto out_unlock_fown; 605 606 ret = 1; 607 608 read_lock(&tasklist_lock); 609 do_each_pid_task(pid, type, p) { 610 send_sigurg_to_task(p, fown, group); 611 } while_each_pid_task(pid, type, p); 612 read_unlock(&tasklist_lock); 613 out_unlock_fown: 614 read_unlock(&fown->lock); 615 return ret; 616} 617 618static DEFINE_SPINLOCK(fasync_lock); 619static struct kmem_cache *fasync_cache __read_mostly; 620 621static void fasync_free_rcu(struct rcu_head *head) 622{ 623 kmem_cache_free(fasync_cache, 624 container_of(head, struct fasync_struct, fa_rcu)); 625} 626 627/* 628 * Remove a fasync entry. If successfully removed, return 629 * positive and clear the FASYNC flag. If no entry exists, 630 * do nothing and return 0. 631 * 632 * NOTE! It is very important that the FASYNC flag always 633 * match the state "is the filp on a fasync list". 634 * 635 */ 636static int fasync_remove_entry(struct file *filp, struct fasync_struct **fapp) 637{ 638 struct fasync_struct *fa, **fp; 639 int result = 0; 640 641 spin_lock(&filp->f_lock); 642 spin_lock(&fasync_lock); 643 for (fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) { 644 if (fa->fa_file != filp) 645 continue; 646 647 spin_lock_irq(&fa->fa_lock); 648 fa->fa_file = NULL; 649 spin_unlock_irq(&fa->fa_lock); 650 651 *fp = fa->fa_next; 652 call_rcu(&fa->fa_rcu, fasync_free_rcu); 653 filp->f_flags &= ~FASYNC; 654 result = 1; 655 break; 656 } 657 spin_unlock(&fasync_lock); 658 spin_unlock(&filp->f_lock); 659 return result; 660} 661 662/* 663 * Add a fasync entry. Return negative on error, positive if 664 * added, and zero if did nothing but change an existing one. 665 * 666 * NOTE! It is very important that the FASYNC flag always 667 * match the state "is the filp on a fasync list". 668 */ 669static int fasync_add_entry(int fd, struct file *filp, struct fasync_struct **fapp) 670{ 671 struct fasync_struct *new, *fa, **fp; 672 int result = 0; 673 674 new = kmem_cache_alloc(fasync_cache, GFP_KERNEL); 675 if (!new) 676 return -ENOMEM; 677 678 spin_lock(&filp->f_lock); 679 spin_lock(&fasync_lock); 680 for (fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) { 681 if (fa->fa_file != filp) 682 continue; 683 684 spin_lock_irq(&fa->fa_lock); 685 fa->fa_fd = fd; 686 spin_unlock_irq(&fa->fa_lock); 687 688 kmem_cache_free(fasync_cache, new); 689 goto out; 690 } 691 692 spin_lock_init(&new->fa_lock); 693 new->magic = FASYNC_MAGIC; 694 new->fa_file = filp; 695 new->fa_fd = fd; 696 new->fa_next = *fapp; 697 rcu_assign_pointer(*fapp, new); 698 result = 1; 699 filp->f_flags |= FASYNC; 700 701out: 702 spin_unlock(&fasync_lock); 703 spin_unlock(&filp->f_lock); 704 return result; 705} 706 707/* 708 * fasync_helper() is used by almost all character device drivers 709 * to set up the fasync queue, and for regular files by the file 710 * lease code. It returns negative on error, 0 if it did no changes 711 * and positive if it added/deleted the entry. 712 */ 713int fasync_helper(int fd, struct file * filp, int on, struct fasync_struct **fapp) 714{ 715 if (!on) 716 return fasync_remove_entry(filp, fapp); 717 return fasync_add_entry(fd, filp, fapp); 718} 719 720EXPORT_SYMBOL(fasync_helper); 721 722/* 723 * rcu_read_lock() is held 724 */ 725static void kill_fasync_rcu(struct fasync_struct *fa, int sig, int band) 726{ 727 while (fa) { 728 struct fown_struct *fown; 729 unsigned long flags; 730 731 if (fa->magic != FASYNC_MAGIC) { 732 printk(KERN_ERR "kill_fasync: bad magic number in " 733 "fasync_struct!\n"); 734 return; 735 } 736 spin_lock_irqsave(&fa->fa_lock, flags); 737 if (fa->fa_file) { 738 fown = &fa->fa_file->f_owner; 739 /* Don't send SIGURG to processes which have not set a 740 queued signum: SIGURG has its own default signalling 741 mechanism. */ 742 if (!(sig == SIGURG && fown->signum == 0)) 743 send_sigio(fown, fa->fa_fd, band); 744 } 745 spin_unlock_irqrestore(&fa->fa_lock, flags); 746 fa = rcu_dereference(fa->fa_next); 747 } 748} 749 750void kill_fasync(struct fasync_struct **fp, int sig, int band) 751{ 752 /* First a quick test without locking: usually 753 * the list is empty. 754 */ 755 if (*fp) { 756 rcu_read_lock(); 757 kill_fasync_rcu(rcu_dereference(*fp), sig, band); 758 rcu_read_unlock(); 759 } 760} 761EXPORT_SYMBOL(kill_fasync); 762 763static int __init fcntl_init(void) 764{ 765 /* 766 * Please add new bits here to ensure allocation uniqueness. 767 * Exceptions: O_NONBLOCK is a two bit define on parisc; O_NDELAY 768 * is defined as O_NONBLOCK on some platforms and not on others. 769 */ 770 BUILD_BUG_ON(18 - 1 /* for O_RDONLY being 0 */ != HWEIGHT32( 771 O_RDONLY | O_WRONLY | O_RDWR | 772 O_CREAT | O_EXCL | O_NOCTTY | 773 O_TRUNC | O_APPEND | /* O_NONBLOCK | */ 774 __O_SYNC | O_DSYNC | FASYNC | 775 O_DIRECT | O_LARGEFILE | O_DIRECTORY | 776 O_NOFOLLOW | O_NOATIME | O_CLOEXEC | 777 FMODE_EXEC 778 )); 779 780 fasync_cache = kmem_cache_create("fasync_cache", 781 sizeof(struct fasync_struct), 0, SLAB_PANIC, NULL); 782 return 0; 783} 784 785module_init(fcntl_init) 786