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 28 void 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 __set_close_on_exec(fd, fdt); 36 else 37 __clear_close_on_exec(fd, fdt); 38 spin_unlock(&files->file_lock); 39 } 40 41 static bool get_close_on_exec(unsigned int fd) 42 { 43 struct files_struct *files = current->files; 44 struct fdtable *fdt; 45 bool res; 46 rcu_read_lock(); 47 fdt = files_fdtable(files); 48 res = close_on_exec(fd, fdt); 49 rcu_read_unlock(); 50 return res; 51 } 52 53 SYSCALL_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_is_open(newfd, fdt)) 94 goto out_unlock; 95 get_file(file); 96 rcu_assign_pointer(fdt->fd[newfd], file); 97 __set_open_fd(newfd, fdt); 98 if (flags & O_CLOEXEC) 99 __set_close_on_exec(newfd, fdt); 100 else 101 __clear_close_on_exec(newfd, fdt); 102 spin_unlock(&files->file_lock); 103 104 if (tofree) 105 filp_close(tofree, files); 106 107 return newfd; 108 109 Ebadf: 110 err = -EBADF; 111 out_unlock: 112 spin_unlock(&files->file_lock); 113 return err; 114 } 115 116 SYSCALL_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 } 130 131 SYSCALL_DEFINE1(dup, unsigned int, fildes) 132 { 133 int ret = -EBADF; 134 struct file *file = fget_raw(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) 147 148 static 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 (!inode_owner_or_capable(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 } 199 200 static 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 } 217 218 int __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 } 230 EXPORT_SYMBOL(__f_setown); 231 232 int 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 } 249 EXPORT_SYMBOL(f_setown); 250 251 void f_delown(struct file *filp) 252 { 253 f_modown(filp, NULL, PIDTYPE_PID, 1); 254 } 255 256 pid_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 } 266 267 static 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 } 306 307 static 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 } 342 343 static 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 /* 381 * XXX If f_owner is a process group, the 382 * negative return value will get converted 383 * into an error. Oops. If we keep the 384 * current syscall conventions, the only way 385 * to fix this will be in libc. 386 */ 387 err = f_getown(filp); 388 force_successful_syscall_return(); 389 break; 390 case F_SETOWN: 391 err = f_setown(filp, arg, 1); 392 break; 393 case F_GETOWN_EX: 394 err = f_getown_ex(filp, arg); 395 break; 396 case F_SETOWN_EX: 397 err = f_setown_ex(filp, arg); 398 break; 399 case F_GETSIG: 400 err = filp->f_owner.signum; 401 break; 402 case F_SETSIG: 403 /* arg == 0 restores default behaviour. */ 404 if (!valid_signal(arg)) { 405 break; 406 } 407 err = 0; 408 filp->f_owner.signum = arg; 409 break; 410 case F_GETLEASE: 411 err = fcntl_getlease(filp); 412 break; 413 case F_SETLEASE: 414 err = fcntl_setlease(fd, filp, arg); 415 break; 416 case F_NOTIFY: 417 err = fcntl_dirnotify(fd, filp, arg); 418 break; 419 case F_SETPIPE_SZ: 420 case F_GETPIPE_SZ: 421 err = pipe_fcntl(filp, cmd, arg); 422 break; 423 default: 424 break; 425 } 426 return err; 427 } 428 429 static int check_fcntl_cmd(unsigned cmd) 430 { 431 switch (cmd) { 432 case F_DUPFD: 433 case F_DUPFD_CLOEXEC: 434 case F_GETFD: 435 case F_SETFD: 436 case F_GETFL: 437 return 1; 438 } 439 return 0; 440 } 441 442 SYSCALL_DEFINE3(fcntl, unsigned int, fd, unsigned int, cmd, unsigned long, arg) 443 { 444 struct file *filp; 445 int fput_needed; 446 long err = -EBADF; 447 448 filp = fget_raw_light(fd, &fput_needed); 449 if (!filp) 450 goto out; 451 452 if (unlikely(filp->f_mode & FMODE_PATH)) { 453 if (!check_fcntl_cmd(cmd)) 454 goto out1; 455 } 456 457 err = security_file_fcntl(filp, cmd, arg); 458 if (!err) 459 err = do_fcntl(fd, cmd, arg, filp); 460 461 out1: 462 fput_light(filp, fput_needed); 463 out: 464 return err; 465 } 466 467 #if BITS_PER_LONG == 32 468 SYSCALL_DEFINE3(fcntl64, unsigned int, fd, unsigned int, cmd, 469 unsigned long, arg) 470 { 471 struct file * filp; 472 long err = -EBADF; 473 int fput_needed; 474 475 filp = fget_raw_light(fd, &fput_needed); 476 if (!filp) 477 goto out; 478 479 if (unlikely(filp->f_mode & FMODE_PATH)) { 480 if (!check_fcntl_cmd(cmd)) 481 goto out1; 482 } 483 484 err = security_file_fcntl(filp, cmd, arg); 485 if (err) 486 goto out1; 487 488 switch (cmd) { 489 case F_GETLK64: 490 err = fcntl_getlk64(filp, (struct flock64 __user *) arg); 491 break; 492 case F_SETLK64: 493 case F_SETLKW64: 494 err = fcntl_setlk64(fd, filp, cmd, 495 (struct flock64 __user *) arg); 496 break; 497 default: 498 err = do_fcntl(fd, cmd, arg, filp); 499 break; 500 } 501 out1: 502 fput_light(filp, fput_needed); 503 out: 504 return err; 505 } 506 #endif 507 508 /* Table to convert sigio signal codes into poll band bitmaps */ 509 510 static const long band_table[NSIGPOLL] = { 511 POLLIN | POLLRDNORM, /* POLL_IN */ 512 POLLOUT | POLLWRNORM | POLLWRBAND, /* POLL_OUT */ 513 POLLIN | POLLRDNORM | POLLMSG, /* POLL_MSG */ 514 POLLERR, /* POLL_ERR */ 515 POLLPRI | POLLRDBAND, /* POLL_PRI */ 516 POLLHUP | POLLERR /* POLL_HUP */ 517 }; 518 519 static inline int sigio_perm(struct task_struct *p, 520 struct fown_struct *fown, int sig) 521 { 522 const struct cred *cred; 523 int ret; 524 525 rcu_read_lock(); 526 cred = __task_cred(p); 527 ret = ((uid_eq(fown->euid, GLOBAL_ROOT_UID) || 528 uid_eq(fown->euid, cred->suid) || uid_eq(fown->euid, cred->uid) || 529 uid_eq(fown->uid, cred->suid) || uid_eq(fown->uid, cred->uid)) && 530 !security_file_send_sigiotask(p, fown, sig)); 531 rcu_read_unlock(); 532 return ret; 533 } 534 535 static void send_sigio_to_task(struct task_struct *p, 536 struct fown_struct *fown, 537 int fd, int reason, int group) 538 { 539 /* 540 * F_SETSIG can change ->signum lockless in parallel, make 541 * sure we read it once and use the same value throughout. 542 */ 543 int signum = ACCESS_ONCE(fown->signum); 544 545 if (!sigio_perm(p, fown, signum)) 546 return; 547 548 switch (signum) { 549 siginfo_t si; 550 default: 551 /* Queue a rt signal with the appropriate fd as its 552 value. We use SI_SIGIO as the source, not 553 SI_KERNEL, since kernel signals always get 554 delivered even if we can't queue. Failure to 555 queue in this case _should_ be reported; we fall 556 back to SIGIO in that case. --sct */ 557 si.si_signo = signum; 558 si.si_errno = 0; 559 si.si_code = reason; 560 /* Make sure we are called with one of the POLL_* 561 reasons, otherwise we could leak kernel stack into 562 userspace. */ 563 BUG_ON((reason & __SI_MASK) != __SI_POLL); 564 if (reason - POLL_IN >= NSIGPOLL) 565 si.si_band = ~0L; 566 else 567 si.si_band = band_table[reason - POLL_IN]; 568 si.si_fd = fd; 569 if (!do_send_sig_info(signum, &si, p, group)) 570 break; 571 /* fall-through: fall back on the old plain SIGIO signal */ 572 case 0: 573 do_send_sig_info(SIGIO, SEND_SIG_PRIV, p, group); 574 } 575 } 576 577 void send_sigio(struct fown_struct *fown, int fd, int band) 578 { 579 struct task_struct *p; 580 enum pid_type type; 581 struct pid *pid; 582 int group = 1; 583 584 read_lock(&fown->lock); 585 586 type = fown->pid_type; 587 if (type == PIDTYPE_MAX) { 588 group = 0; 589 type = PIDTYPE_PID; 590 } 591 592 pid = fown->pid; 593 if (!pid) 594 goto out_unlock_fown; 595 596 read_lock(&tasklist_lock); 597 do_each_pid_task(pid, type, p) { 598 send_sigio_to_task(p, fown, fd, band, group); 599 } while_each_pid_task(pid, type, p); 600 read_unlock(&tasklist_lock); 601 out_unlock_fown: 602 read_unlock(&fown->lock); 603 } 604 605 static void send_sigurg_to_task(struct task_struct *p, 606 struct fown_struct *fown, int group) 607 { 608 if (sigio_perm(p, fown, SIGURG)) 609 do_send_sig_info(SIGURG, SEND_SIG_PRIV, p, group); 610 } 611 612 int send_sigurg(struct fown_struct *fown) 613 { 614 struct task_struct *p; 615 enum pid_type type; 616 struct pid *pid; 617 int group = 1; 618 int ret = 0; 619 620 read_lock(&fown->lock); 621 622 type = fown->pid_type; 623 if (type == PIDTYPE_MAX) { 624 group = 0; 625 type = PIDTYPE_PID; 626 } 627 628 pid = fown->pid; 629 if (!pid) 630 goto out_unlock_fown; 631 632 ret = 1; 633 634 read_lock(&tasklist_lock); 635 do_each_pid_task(pid, type, p) { 636 send_sigurg_to_task(p, fown, group); 637 } while_each_pid_task(pid, type, p); 638 read_unlock(&tasklist_lock); 639 out_unlock_fown: 640 read_unlock(&fown->lock); 641 return ret; 642 } 643 644 static DEFINE_SPINLOCK(fasync_lock); 645 static struct kmem_cache *fasync_cache __read_mostly; 646 647 static void fasync_free_rcu(struct rcu_head *head) 648 { 649 kmem_cache_free(fasync_cache, 650 container_of(head, struct fasync_struct, fa_rcu)); 651 } 652 653 /* 654 * Remove a fasync entry. If successfully removed, return 655 * positive and clear the FASYNC flag. If no entry exists, 656 * do nothing and return 0. 657 * 658 * NOTE! It is very important that the FASYNC flag always 659 * match the state "is the filp on a fasync list". 660 * 661 */ 662 int fasync_remove_entry(struct file *filp, struct fasync_struct **fapp) 663 { 664 struct fasync_struct *fa, **fp; 665 int result = 0; 666 667 spin_lock(&filp->f_lock); 668 spin_lock(&fasync_lock); 669 for (fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) { 670 if (fa->fa_file != filp) 671 continue; 672 673 spin_lock_irq(&fa->fa_lock); 674 fa->fa_file = NULL; 675 spin_unlock_irq(&fa->fa_lock); 676 677 *fp = fa->fa_next; 678 call_rcu(&fa->fa_rcu, fasync_free_rcu); 679 filp->f_flags &= ~FASYNC; 680 result = 1; 681 break; 682 } 683 spin_unlock(&fasync_lock); 684 spin_unlock(&filp->f_lock); 685 return result; 686 } 687 688 struct fasync_struct *fasync_alloc(void) 689 { 690 return kmem_cache_alloc(fasync_cache, GFP_KERNEL); 691 } 692 693 /* 694 * NOTE! This can be used only for unused fasync entries: 695 * entries that actually got inserted on the fasync list 696 * need to be released by rcu - see fasync_remove_entry. 697 */ 698 void fasync_free(struct fasync_struct *new) 699 { 700 kmem_cache_free(fasync_cache, new); 701 } 702 703 /* 704 * Insert a new entry into the fasync list. Return the pointer to the 705 * old one if we didn't use the new one. 706 * 707 * NOTE! It is very important that the FASYNC flag always 708 * match the state "is the filp on a fasync list". 709 */ 710 struct fasync_struct *fasync_insert_entry(int fd, struct file *filp, struct fasync_struct **fapp, struct fasync_struct *new) 711 { 712 struct fasync_struct *fa, **fp; 713 714 spin_lock(&filp->f_lock); 715 spin_lock(&fasync_lock); 716 for (fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) { 717 if (fa->fa_file != filp) 718 continue; 719 720 spin_lock_irq(&fa->fa_lock); 721 fa->fa_fd = fd; 722 spin_unlock_irq(&fa->fa_lock); 723 goto out; 724 } 725 726 spin_lock_init(&new->fa_lock); 727 new->magic = FASYNC_MAGIC; 728 new->fa_file = filp; 729 new->fa_fd = fd; 730 new->fa_next = *fapp; 731 rcu_assign_pointer(*fapp, new); 732 filp->f_flags |= FASYNC; 733 734 out: 735 spin_unlock(&fasync_lock); 736 spin_unlock(&filp->f_lock); 737 return fa; 738 } 739 740 /* 741 * Add a fasync entry. Return negative on error, positive if 742 * added, and zero if did nothing but change an existing one. 743 */ 744 static int fasync_add_entry(int fd, struct file *filp, struct fasync_struct **fapp) 745 { 746 struct fasync_struct *new; 747 748 new = fasync_alloc(); 749 if (!new) 750 return -ENOMEM; 751 752 /* 753 * fasync_insert_entry() returns the old (update) entry if 754 * it existed. 755 * 756 * So free the (unused) new entry and return 0 to let the 757 * caller know that we didn't add any new fasync entries. 758 */ 759 if (fasync_insert_entry(fd, filp, fapp, new)) { 760 fasync_free(new); 761 return 0; 762 } 763 764 return 1; 765 } 766 767 /* 768 * fasync_helper() is used by almost all character device drivers 769 * to set up the fasync queue, and for regular files by the file 770 * lease code. It returns negative on error, 0 if it did no changes 771 * and positive if it added/deleted the entry. 772 */ 773 int fasync_helper(int fd, struct file * filp, int on, struct fasync_struct **fapp) 774 { 775 if (!on) 776 return fasync_remove_entry(filp, fapp); 777 return fasync_add_entry(fd, filp, fapp); 778 } 779 780 EXPORT_SYMBOL(fasync_helper); 781 782 /* 783 * rcu_read_lock() is held 784 */ 785 static void kill_fasync_rcu(struct fasync_struct *fa, int sig, int band) 786 { 787 while (fa) { 788 struct fown_struct *fown; 789 unsigned long flags; 790 791 if (fa->magic != FASYNC_MAGIC) { 792 printk(KERN_ERR "kill_fasync: bad magic number in " 793 "fasync_struct!\n"); 794 return; 795 } 796 spin_lock_irqsave(&fa->fa_lock, flags); 797 if (fa->fa_file) { 798 fown = &fa->fa_file->f_owner; 799 /* Don't send SIGURG to processes which have not set a 800 queued signum: SIGURG has its own default signalling 801 mechanism. */ 802 if (!(sig == SIGURG && fown->signum == 0)) 803 send_sigio(fown, fa->fa_fd, band); 804 } 805 spin_unlock_irqrestore(&fa->fa_lock, flags); 806 fa = rcu_dereference(fa->fa_next); 807 } 808 } 809 810 void kill_fasync(struct fasync_struct **fp, int sig, int band) 811 { 812 /* First a quick test without locking: usually 813 * the list is empty. 814 */ 815 if (*fp) { 816 rcu_read_lock(); 817 kill_fasync_rcu(rcu_dereference(*fp), sig, band); 818 rcu_read_unlock(); 819 } 820 } 821 EXPORT_SYMBOL(kill_fasync); 822 823 static int __init fcntl_init(void) 824 { 825 /* 826 * Please add new bits here to ensure allocation uniqueness. 827 * Exceptions: O_NONBLOCK is a two bit define on parisc; O_NDELAY 828 * is defined as O_NONBLOCK on some platforms and not on others. 829 */ 830 BUILD_BUG_ON(19 - 1 /* for O_RDONLY being 0 */ != HWEIGHT32( 831 O_RDONLY | O_WRONLY | O_RDWR | 832 O_CREAT | O_EXCL | O_NOCTTY | 833 O_TRUNC | O_APPEND | /* O_NONBLOCK | */ 834 __O_SYNC | O_DSYNC | FASYNC | 835 O_DIRECT | O_LARGEFILE | O_DIRECTORY | 836 O_NOFOLLOW | O_NOATIME | O_CLOEXEC | 837 __FMODE_EXEC | O_PATH 838 )); 839 840 fasync_cache = kmem_cache_create("fasync_cache", 841 sizeof(struct fasync_struct), 0, SLAB_PANIC, NULL); 842 return 0; 843 } 844 845 module_init(fcntl_init) 846