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/sched/task.h> 11 #include <linux/fs.h> 12 #include <linux/file.h> 13 #include <linux/fdtable.h> 14 #include <linux/capability.h> 15 #include <linux/dnotify.h> 16 #include <linux/slab.h> 17 #include <linux/module.h> 18 #include <linux/pipe_fs_i.h> 19 #include <linux/security.h> 20 #include <linux/ptrace.h> 21 #include <linux/signal.h> 22 #include <linux/rcupdate.h> 23 #include <linux/pid_namespace.h> 24 #include <linux/user_namespace.h> 25 #include <linux/shmem_fs.h> 26 #include <linux/compat.h> 27 28 #include <asm/poll.h> 29 #include <asm/siginfo.h> 30 #include <linux/uaccess.h> 31 32 #define SETFL_MASK (O_APPEND | O_NONBLOCK | O_NDELAY | O_DIRECT | O_NOATIME) 33 34 static int setfl(int fd, struct file * filp, unsigned long arg) 35 { 36 struct inode * inode = file_inode(filp); 37 int error = 0; 38 39 /* 40 * O_APPEND cannot be cleared if the file is marked as append-only 41 * and the file is open for write. 42 */ 43 if (((arg ^ filp->f_flags) & O_APPEND) && IS_APPEND(inode)) 44 return -EPERM; 45 46 /* O_NOATIME can only be set by the owner or superuser */ 47 if ((arg & O_NOATIME) && !(filp->f_flags & O_NOATIME)) 48 if (!inode_owner_or_capable(inode)) 49 return -EPERM; 50 51 /* required for strict SunOS emulation */ 52 if (O_NONBLOCK != O_NDELAY) 53 if (arg & O_NDELAY) 54 arg |= O_NONBLOCK; 55 56 /* Pipe packetized mode is controlled by O_DIRECT flag */ 57 if (!S_ISFIFO(inode->i_mode) && (arg & O_DIRECT)) { 58 if (!filp->f_mapping || !filp->f_mapping->a_ops || 59 !filp->f_mapping->a_ops->direct_IO) 60 return -EINVAL; 61 } 62 63 if (filp->f_op->check_flags) 64 error = filp->f_op->check_flags(arg); 65 if (error) 66 return error; 67 68 /* 69 * ->fasync() is responsible for setting the FASYNC bit. 70 */ 71 if (((arg ^ filp->f_flags) & FASYNC) && filp->f_op->fasync) { 72 error = filp->f_op->fasync(fd, filp, (arg & FASYNC) != 0); 73 if (error < 0) 74 goto out; 75 if (error > 0) 76 error = 0; 77 } 78 spin_lock(&filp->f_lock); 79 filp->f_flags = (arg & SETFL_MASK) | (filp->f_flags & ~SETFL_MASK); 80 spin_unlock(&filp->f_lock); 81 82 out: 83 return error; 84 } 85 86 static void f_modown(struct file *filp, struct pid *pid, enum pid_type type, 87 int force) 88 { 89 write_lock_irq(&filp->f_owner.lock); 90 if (force || !filp->f_owner.pid) { 91 put_pid(filp->f_owner.pid); 92 filp->f_owner.pid = get_pid(pid); 93 filp->f_owner.pid_type = type; 94 95 if (pid) { 96 const struct cred *cred = current_cred(); 97 filp->f_owner.uid = cred->uid; 98 filp->f_owner.euid = cred->euid; 99 } 100 } 101 write_unlock_irq(&filp->f_owner.lock); 102 } 103 104 void __f_setown(struct file *filp, struct pid *pid, enum pid_type type, 105 int force) 106 { 107 security_file_set_fowner(filp); 108 f_modown(filp, pid, type, force); 109 } 110 EXPORT_SYMBOL(__f_setown); 111 112 int f_setown(struct file *filp, unsigned long arg, int force) 113 { 114 enum pid_type type; 115 struct pid *pid = NULL; 116 int who = arg, ret = 0; 117 118 type = PIDTYPE_PID; 119 if (who < 0) { 120 /* avoid overflow below */ 121 if (who == INT_MIN) 122 return -EINVAL; 123 124 type = PIDTYPE_PGID; 125 who = -who; 126 } 127 128 rcu_read_lock(); 129 if (who) { 130 pid = find_vpid(who); 131 if (!pid) 132 ret = -ESRCH; 133 } 134 135 if (!ret) 136 __f_setown(filp, pid, type, force); 137 rcu_read_unlock(); 138 139 return ret; 140 } 141 EXPORT_SYMBOL(f_setown); 142 143 void f_delown(struct file *filp) 144 { 145 f_modown(filp, NULL, PIDTYPE_PID, 1); 146 } 147 148 pid_t f_getown(struct file *filp) 149 { 150 pid_t pid; 151 read_lock(&filp->f_owner.lock); 152 pid = pid_vnr(filp->f_owner.pid); 153 if (filp->f_owner.pid_type == PIDTYPE_PGID) 154 pid = -pid; 155 read_unlock(&filp->f_owner.lock); 156 return pid; 157 } 158 159 static int f_setown_ex(struct file *filp, unsigned long arg) 160 { 161 struct f_owner_ex __user *owner_p = (void __user *)arg; 162 struct f_owner_ex owner; 163 struct pid *pid; 164 int type; 165 int ret; 166 167 ret = copy_from_user(&owner, owner_p, sizeof(owner)); 168 if (ret) 169 return -EFAULT; 170 171 switch (owner.type) { 172 case F_OWNER_TID: 173 type = PIDTYPE_MAX; 174 break; 175 176 case F_OWNER_PID: 177 type = PIDTYPE_PID; 178 break; 179 180 case F_OWNER_PGRP: 181 type = PIDTYPE_PGID; 182 break; 183 184 default: 185 return -EINVAL; 186 } 187 188 rcu_read_lock(); 189 pid = find_vpid(owner.pid); 190 if (owner.pid && !pid) 191 ret = -ESRCH; 192 else 193 __f_setown(filp, pid, type, 1); 194 rcu_read_unlock(); 195 196 return ret; 197 } 198 199 static int f_getown_ex(struct file *filp, unsigned long arg) 200 { 201 struct f_owner_ex __user *owner_p = (void __user *)arg; 202 struct f_owner_ex owner; 203 int ret = 0; 204 205 read_lock(&filp->f_owner.lock); 206 owner.pid = pid_vnr(filp->f_owner.pid); 207 switch (filp->f_owner.pid_type) { 208 case PIDTYPE_MAX: 209 owner.type = F_OWNER_TID; 210 break; 211 212 case PIDTYPE_PID: 213 owner.type = F_OWNER_PID; 214 break; 215 216 case PIDTYPE_PGID: 217 owner.type = F_OWNER_PGRP; 218 break; 219 220 default: 221 WARN_ON(1); 222 ret = -EINVAL; 223 break; 224 } 225 read_unlock(&filp->f_owner.lock); 226 227 if (!ret) { 228 ret = copy_to_user(owner_p, &owner, sizeof(owner)); 229 if (ret) 230 ret = -EFAULT; 231 } 232 return ret; 233 } 234 235 #ifdef CONFIG_CHECKPOINT_RESTORE 236 static int f_getowner_uids(struct file *filp, unsigned long arg) 237 { 238 struct user_namespace *user_ns = current_user_ns(); 239 uid_t __user *dst = (void __user *)arg; 240 uid_t src[2]; 241 int err; 242 243 read_lock(&filp->f_owner.lock); 244 src[0] = from_kuid(user_ns, filp->f_owner.uid); 245 src[1] = from_kuid(user_ns, filp->f_owner.euid); 246 read_unlock(&filp->f_owner.lock); 247 248 err = put_user(src[0], &dst[0]); 249 err |= put_user(src[1], &dst[1]); 250 251 return err; 252 } 253 #else 254 static int f_getowner_uids(struct file *filp, unsigned long arg) 255 { 256 return -EINVAL; 257 } 258 #endif 259 260 static bool rw_hint_valid(enum rw_hint hint) 261 { 262 switch (hint) { 263 case RWF_WRITE_LIFE_NOT_SET: 264 case RWH_WRITE_LIFE_NONE: 265 case RWH_WRITE_LIFE_SHORT: 266 case RWH_WRITE_LIFE_MEDIUM: 267 case RWH_WRITE_LIFE_LONG: 268 case RWH_WRITE_LIFE_EXTREME: 269 return true; 270 default: 271 return false; 272 } 273 } 274 275 static long fcntl_rw_hint(struct file *file, unsigned int cmd, 276 unsigned long arg) 277 { 278 struct inode *inode = file_inode(file); 279 u64 *argp = (u64 __user *)arg; 280 enum rw_hint hint; 281 u64 h; 282 283 switch (cmd) { 284 case F_GET_FILE_RW_HINT: 285 h = file_write_hint(file); 286 if (copy_to_user(argp, &h, sizeof(*argp))) 287 return -EFAULT; 288 return 0; 289 case F_SET_FILE_RW_HINT: 290 if (copy_from_user(&h, argp, sizeof(h))) 291 return -EFAULT; 292 hint = (enum rw_hint) h; 293 if (!rw_hint_valid(hint)) 294 return -EINVAL; 295 296 spin_lock(&file->f_lock); 297 file->f_write_hint = hint; 298 spin_unlock(&file->f_lock); 299 return 0; 300 case F_GET_RW_HINT: 301 h = inode->i_write_hint; 302 if (copy_to_user(argp, &h, sizeof(*argp))) 303 return -EFAULT; 304 return 0; 305 case F_SET_RW_HINT: 306 if (copy_from_user(&h, argp, sizeof(h))) 307 return -EFAULT; 308 hint = (enum rw_hint) h; 309 if (!rw_hint_valid(hint)) 310 return -EINVAL; 311 312 inode_lock(inode); 313 inode->i_write_hint = hint; 314 inode_unlock(inode); 315 return 0; 316 default: 317 return -EINVAL; 318 } 319 } 320 321 static long do_fcntl(int fd, unsigned int cmd, unsigned long arg, 322 struct file *filp) 323 { 324 void __user *argp = (void __user *)arg; 325 struct flock flock; 326 long err = -EINVAL; 327 328 switch (cmd) { 329 case F_DUPFD: 330 err = f_dupfd(arg, filp, 0); 331 break; 332 case F_DUPFD_CLOEXEC: 333 err = f_dupfd(arg, filp, O_CLOEXEC); 334 break; 335 case F_GETFD: 336 err = get_close_on_exec(fd) ? FD_CLOEXEC : 0; 337 break; 338 case F_SETFD: 339 err = 0; 340 set_close_on_exec(fd, arg & FD_CLOEXEC); 341 break; 342 case F_GETFL: 343 err = filp->f_flags; 344 break; 345 case F_SETFL: 346 err = setfl(fd, filp, arg); 347 break; 348 #if BITS_PER_LONG != 32 349 /* 32-bit arches must use fcntl64() */ 350 case F_OFD_GETLK: 351 #endif 352 case F_GETLK: 353 if (copy_from_user(&flock, argp, sizeof(flock))) 354 return -EFAULT; 355 err = fcntl_getlk(filp, cmd, &flock); 356 if (!err && copy_to_user(argp, &flock, sizeof(flock))) 357 return -EFAULT; 358 break; 359 #if BITS_PER_LONG != 32 360 /* 32-bit arches must use fcntl64() */ 361 case F_OFD_SETLK: 362 case F_OFD_SETLKW: 363 #endif 364 /* Fallthrough */ 365 case F_SETLK: 366 case F_SETLKW: 367 if (copy_from_user(&flock, argp, sizeof(flock))) 368 return -EFAULT; 369 err = fcntl_setlk(fd, filp, cmd, &flock); 370 break; 371 case F_GETOWN: 372 /* 373 * XXX If f_owner is a process group, the 374 * negative return value will get converted 375 * into an error. Oops. If we keep the 376 * current syscall conventions, the only way 377 * to fix this will be in libc. 378 */ 379 err = f_getown(filp); 380 force_successful_syscall_return(); 381 break; 382 case F_SETOWN: 383 err = f_setown(filp, arg, 1); 384 break; 385 case F_GETOWN_EX: 386 err = f_getown_ex(filp, arg); 387 break; 388 case F_SETOWN_EX: 389 err = f_setown_ex(filp, arg); 390 break; 391 case F_GETOWNER_UIDS: 392 err = f_getowner_uids(filp, arg); 393 break; 394 case F_GETSIG: 395 err = filp->f_owner.signum; 396 break; 397 case F_SETSIG: 398 /* arg == 0 restores default behaviour. */ 399 if (!valid_signal(arg)) { 400 break; 401 } 402 err = 0; 403 filp->f_owner.signum = arg; 404 break; 405 case F_GETLEASE: 406 err = fcntl_getlease(filp); 407 break; 408 case F_SETLEASE: 409 err = fcntl_setlease(fd, filp, arg); 410 break; 411 case F_NOTIFY: 412 err = fcntl_dirnotify(fd, filp, arg); 413 break; 414 case F_SETPIPE_SZ: 415 case F_GETPIPE_SZ: 416 err = pipe_fcntl(filp, cmd, arg); 417 break; 418 case F_ADD_SEALS: 419 case F_GET_SEALS: 420 err = shmem_fcntl(filp, cmd, arg); 421 break; 422 case F_GET_RW_HINT: 423 case F_SET_RW_HINT: 424 case F_GET_FILE_RW_HINT: 425 case F_SET_FILE_RW_HINT: 426 err = fcntl_rw_hint(filp, cmd, arg); 427 break; 428 default: 429 break; 430 } 431 return err; 432 } 433 434 static int check_fcntl_cmd(unsigned cmd) 435 { 436 switch (cmd) { 437 case F_DUPFD: 438 case F_DUPFD_CLOEXEC: 439 case F_GETFD: 440 case F_SETFD: 441 case F_GETFL: 442 return 1; 443 } 444 return 0; 445 } 446 447 SYSCALL_DEFINE3(fcntl, unsigned int, fd, unsigned int, cmd, unsigned long, arg) 448 { 449 struct fd f = fdget_raw(fd); 450 long err = -EBADF; 451 452 if (!f.file) 453 goto out; 454 455 if (unlikely(f.file->f_mode & FMODE_PATH)) { 456 if (!check_fcntl_cmd(cmd)) 457 goto out1; 458 } 459 460 err = security_file_fcntl(f.file, cmd, arg); 461 if (!err) 462 err = do_fcntl(fd, cmd, arg, f.file); 463 464 out1: 465 fdput(f); 466 out: 467 return err; 468 } 469 470 #if BITS_PER_LONG == 32 471 SYSCALL_DEFINE3(fcntl64, unsigned int, fd, unsigned int, cmd, 472 unsigned long, arg) 473 { 474 void __user *argp = (void __user *)arg; 475 struct fd f = fdget_raw(fd); 476 struct flock64 flock; 477 long err = -EBADF; 478 479 if (!f.file) 480 goto out; 481 482 if (unlikely(f.file->f_mode & FMODE_PATH)) { 483 if (!check_fcntl_cmd(cmd)) 484 goto out1; 485 } 486 487 err = security_file_fcntl(f.file, cmd, arg); 488 if (err) 489 goto out1; 490 491 switch (cmd) { 492 case F_GETLK64: 493 case F_OFD_GETLK: 494 err = -EFAULT; 495 if (copy_from_user(&flock, argp, sizeof(flock))) 496 break; 497 err = fcntl_getlk64(f.file, cmd, &flock); 498 if (!err && copy_to_user(argp, &flock, sizeof(flock))) 499 err = -EFAULT; 500 break; 501 case F_SETLK64: 502 case F_SETLKW64: 503 case F_OFD_SETLK: 504 case F_OFD_SETLKW: 505 err = -EFAULT; 506 if (copy_from_user(&flock, argp, sizeof(flock))) 507 break; 508 err = fcntl_setlk64(fd, f.file, cmd, &flock); 509 break; 510 default: 511 err = do_fcntl(fd, cmd, arg, f.file); 512 break; 513 } 514 out1: 515 fdput(f); 516 out: 517 return err; 518 } 519 #endif 520 521 #ifdef CONFIG_COMPAT 522 /* careful - don't use anywhere else */ 523 #define copy_flock_fields(dst, src) \ 524 (dst)->l_type = (src)->l_type; \ 525 (dst)->l_whence = (src)->l_whence; \ 526 (dst)->l_start = (src)->l_start; \ 527 (dst)->l_len = (src)->l_len; \ 528 (dst)->l_pid = (src)->l_pid; 529 530 static int get_compat_flock(struct flock *kfl, const struct compat_flock __user *ufl) 531 { 532 struct compat_flock fl; 533 534 if (copy_from_user(&fl, ufl, sizeof(struct compat_flock))) 535 return -EFAULT; 536 copy_flock_fields(kfl, &fl); 537 return 0; 538 } 539 540 static int get_compat_flock64(struct flock *kfl, const struct compat_flock64 __user *ufl) 541 { 542 struct compat_flock64 fl; 543 544 if (copy_from_user(&fl, ufl, sizeof(struct compat_flock64))) 545 return -EFAULT; 546 copy_flock_fields(kfl, &fl); 547 return 0; 548 } 549 550 static int put_compat_flock(const struct flock *kfl, struct compat_flock __user *ufl) 551 { 552 struct compat_flock fl; 553 554 memset(&fl, 0, sizeof(struct compat_flock)); 555 copy_flock_fields(&fl, kfl); 556 if (copy_to_user(ufl, &fl, sizeof(struct compat_flock))) 557 return -EFAULT; 558 return 0; 559 } 560 561 static int put_compat_flock64(const struct flock *kfl, struct compat_flock64 __user *ufl) 562 { 563 struct compat_flock64 fl; 564 565 memset(&fl, 0, sizeof(struct compat_flock64)); 566 copy_flock_fields(&fl, kfl); 567 if (copy_to_user(ufl, &fl, sizeof(struct compat_flock64))) 568 return -EFAULT; 569 return 0; 570 } 571 #undef copy_flock_fields 572 573 static unsigned int 574 convert_fcntl_cmd(unsigned int cmd) 575 { 576 switch (cmd) { 577 case F_GETLK64: 578 return F_GETLK; 579 case F_SETLK64: 580 return F_SETLK; 581 case F_SETLKW64: 582 return F_SETLKW; 583 } 584 585 return cmd; 586 } 587 588 /* 589 * GETLK was successful and we need to return the data, but it needs to fit in 590 * the compat structure. 591 * l_start shouldn't be too big, unless the original start + end is greater than 592 * COMPAT_OFF_T_MAX, in which case the app was asking for trouble, so we return 593 * -EOVERFLOW in that case. l_len could be too big, in which case we just 594 * truncate it, and only allow the app to see that part of the conflicting lock 595 * that might make sense to it anyway 596 */ 597 static int fixup_compat_flock(struct flock *flock) 598 { 599 if (flock->l_start > COMPAT_OFF_T_MAX) 600 return -EOVERFLOW; 601 if (flock->l_len > COMPAT_OFF_T_MAX) 602 flock->l_len = COMPAT_OFF_T_MAX; 603 return 0; 604 } 605 606 COMPAT_SYSCALL_DEFINE3(fcntl64, unsigned int, fd, unsigned int, cmd, 607 compat_ulong_t, arg) 608 { 609 struct fd f = fdget_raw(fd); 610 struct flock flock; 611 long err = -EBADF; 612 613 if (!f.file) 614 return err; 615 616 if (unlikely(f.file->f_mode & FMODE_PATH)) { 617 if (!check_fcntl_cmd(cmd)) 618 goto out_put; 619 } 620 621 err = security_file_fcntl(f.file, cmd, arg); 622 if (err) 623 goto out_put; 624 625 switch (cmd) { 626 case F_GETLK: 627 err = get_compat_flock(&flock, compat_ptr(arg)); 628 if (err) 629 break; 630 err = fcntl_getlk(f.file, convert_fcntl_cmd(cmd), &flock); 631 if (err) 632 break; 633 err = fixup_compat_flock(&flock); 634 if (err) 635 return err; 636 err = put_compat_flock(&flock, compat_ptr(arg)); 637 break; 638 case F_GETLK64: 639 case F_OFD_GETLK: 640 err = get_compat_flock64(&flock, compat_ptr(arg)); 641 if (err) 642 break; 643 err = fcntl_getlk(f.file, convert_fcntl_cmd(cmd), &flock); 644 if (err) 645 break; 646 err = fixup_compat_flock(&flock); 647 if (err) 648 return err; 649 err = put_compat_flock64(&flock, compat_ptr(arg)); 650 break; 651 case F_SETLK: 652 case F_SETLKW: 653 err = get_compat_flock(&flock, compat_ptr(arg)); 654 if (err) 655 break; 656 err = fcntl_setlk(fd, f.file, convert_fcntl_cmd(cmd), &flock); 657 break; 658 case F_SETLK64: 659 case F_SETLKW64: 660 case F_OFD_SETLK: 661 case F_OFD_SETLKW: 662 err = get_compat_flock64(&flock, compat_ptr(arg)); 663 if (err) 664 break; 665 err = fcntl_setlk(fd, f.file, convert_fcntl_cmd(cmd), &flock); 666 break; 667 default: 668 err = do_fcntl(fd, cmd, arg, f.file); 669 break; 670 } 671 out_put: 672 fdput(f); 673 return err; 674 } 675 676 COMPAT_SYSCALL_DEFINE3(fcntl, unsigned int, fd, unsigned int, cmd, 677 compat_ulong_t, arg) 678 { 679 switch (cmd) { 680 case F_GETLK64: 681 case F_SETLK64: 682 case F_SETLKW64: 683 case F_OFD_GETLK: 684 case F_OFD_SETLK: 685 case F_OFD_SETLKW: 686 return -EINVAL; 687 } 688 return compat_sys_fcntl64(fd, cmd, arg); 689 } 690 #endif 691 692 /* Table to convert sigio signal codes into poll band bitmaps */ 693 694 static const long band_table[NSIGPOLL] = { 695 POLLIN | POLLRDNORM, /* POLL_IN */ 696 POLLOUT | POLLWRNORM | POLLWRBAND, /* POLL_OUT */ 697 POLLIN | POLLRDNORM | POLLMSG, /* POLL_MSG */ 698 POLLERR, /* POLL_ERR */ 699 POLLPRI | POLLRDBAND, /* POLL_PRI */ 700 POLLHUP | POLLERR /* POLL_HUP */ 701 }; 702 703 static inline int sigio_perm(struct task_struct *p, 704 struct fown_struct *fown, int sig) 705 { 706 const struct cred *cred; 707 int ret; 708 709 rcu_read_lock(); 710 cred = __task_cred(p); 711 ret = ((uid_eq(fown->euid, GLOBAL_ROOT_UID) || 712 uid_eq(fown->euid, cred->suid) || uid_eq(fown->euid, cred->uid) || 713 uid_eq(fown->uid, cred->suid) || uid_eq(fown->uid, cred->uid)) && 714 !security_file_send_sigiotask(p, fown, sig)); 715 rcu_read_unlock(); 716 return ret; 717 } 718 719 static void send_sigio_to_task(struct task_struct *p, 720 struct fown_struct *fown, 721 int fd, int reason, int group) 722 { 723 /* 724 * F_SETSIG can change ->signum lockless in parallel, make 725 * sure we read it once and use the same value throughout. 726 */ 727 int signum = ACCESS_ONCE(fown->signum); 728 729 if (!sigio_perm(p, fown, signum)) 730 return; 731 732 switch (signum) { 733 siginfo_t si; 734 default: 735 /* Queue a rt signal with the appropriate fd as its 736 value. We use SI_SIGIO as the source, not 737 SI_KERNEL, since kernel signals always get 738 delivered even if we can't queue. Failure to 739 queue in this case _should_ be reported; we fall 740 back to SIGIO in that case. --sct */ 741 si.si_signo = signum; 742 si.si_errno = 0; 743 si.si_code = reason; 744 /* 745 * Posix definies POLL_IN and friends to be signal 746 * specific si_codes for SIG_POLL. Linux extended 747 * these si_codes to other signals in a way that is 748 * ambiguous if other signals also have signal 749 * specific si_codes. In that case use SI_SIGIO instead 750 * to remove the ambiguity. 751 */ 752 if ((signum != SIGPOLL) && sig_specific_sicodes(signum)) 753 si.si_code = SI_SIGIO; 754 755 /* Make sure we are called with one of the POLL_* 756 reasons, otherwise we could leak kernel stack into 757 userspace. */ 758 BUG_ON((reason < POLL_IN) || ((reason - POLL_IN) >= NSIGPOLL)); 759 if (reason - POLL_IN >= NSIGPOLL) 760 si.si_band = ~0L; 761 else 762 si.si_band = band_table[reason - POLL_IN]; 763 si.si_fd = fd; 764 if (!do_send_sig_info(signum, &si, p, group)) 765 break; 766 /* fall-through: fall back on the old plain SIGIO signal */ 767 case 0: 768 do_send_sig_info(SIGIO, SEND_SIG_PRIV, p, group); 769 } 770 } 771 772 void send_sigio(struct fown_struct *fown, int fd, int band) 773 { 774 struct task_struct *p; 775 enum pid_type type; 776 struct pid *pid; 777 int group = 1; 778 779 read_lock(&fown->lock); 780 781 type = fown->pid_type; 782 if (type == PIDTYPE_MAX) { 783 group = 0; 784 type = PIDTYPE_PID; 785 } 786 787 pid = fown->pid; 788 if (!pid) 789 goto out_unlock_fown; 790 791 read_lock(&tasklist_lock); 792 do_each_pid_task(pid, type, p) { 793 send_sigio_to_task(p, fown, fd, band, group); 794 } while_each_pid_task(pid, type, p); 795 read_unlock(&tasklist_lock); 796 out_unlock_fown: 797 read_unlock(&fown->lock); 798 } 799 800 static void send_sigurg_to_task(struct task_struct *p, 801 struct fown_struct *fown, int group) 802 { 803 if (sigio_perm(p, fown, SIGURG)) 804 do_send_sig_info(SIGURG, SEND_SIG_PRIV, p, group); 805 } 806 807 int send_sigurg(struct fown_struct *fown) 808 { 809 struct task_struct *p; 810 enum pid_type type; 811 struct pid *pid; 812 int group = 1; 813 int ret = 0; 814 815 read_lock(&fown->lock); 816 817 type = fown->pid_type; 818 if (type == PIDTYPE_MAX) { 819 group = 0; 820 type = PIDTYPE_PID; 821 } 822 823 pid = fown->pid; 824 if (!pid) 825 goto out_unlock_fown; 826 827 ret = 1; 828 829 read_lock(&tasklist_lock); 830 do_each_pid_task(pid, type, p) { 831 send_sigurg_to_task(p, fown, group); 832 } while_each_pid_task(pid, type, p); 833 read_unlock(&tasklist_lock); 834 out_unlock_fown: 835 read_unlock(&fown->lock); 836 return ret; 837 } 838 839 static DEFINE_SPINLOCK(fasync_lock); 840 static struct kmem_cache *fasync_cache __read_mostly; 841 842 static void fasync_free_rcu(struct rcu_head *head) 843 { 844 kmem_cache_free(fasync_cache, 845 container_of(head, struct fasync_struct, fa_rcu)); 846 } 847 848 /* 849 * Remove a fasync entry. If successfully removed, return 850 * positive and clear the FASYNC flag. If no entry exists, 851 * do nothing and return 0. 852 * 853 * NOTE! It is very important that the FASYNC flag always 854 * match the state "is the filp on a fasync list". 855 * 856 */ 857 int fasync_remove_entry(struct file *filp, struct fasync_struct **fapp) 858 { 859 struct fasync_struct *fa, **fp; 860 int result = 0; 861 862 spin_lock(&filp->f_lock); 863 spin_lock(&fasync_lock); 864 for (fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) { 865 if (fa->fa_file != filp) 866 continue; 867 868 spin_lock_irq(&fa->fa_lock); 869 fa->fa_file = NULL; 870 spin_unlock_irq(&fa->fa_lock); 871 872 *fp = fa->fa_next; 873 call_rcu(&fa->fa_rcu, fasync_free_rcu); 874 filp->f_flags &= ~FASYNC; 875 result = 1; 876 break; 877 } 878 spin_unlock(&fasync_lock); 879 spin_unlock(&filp->f_lock); 880 return result; 881 } 882 883 struct fasync_struct *fasync_alloc(void) 884 { 885 return kmem_cache_alloc(fasync_cache, GFP_KERNEL); 886 } 887 888 /* 889 * NOTE! This can be used only for unused fasync entries: 890 * entries that actually got inserted on the fasync list 891 * need to be released by rcu - see fasync_remove_entry. 892 */ 893 void fasync_free(struct fasync_struct *new) 894 { 895 kmem_cache_free(fasync_cache, new); 896 } 897 898 /* 899 * Insert a new entry into the fasync list. Return the pointer to the 900 * old one if we didn't use the new one. 901 * 902 * NOTE! It is very important that the FASYNC flag always 903 * match the state "is the filp on a fasync list". 904 */ 905 struct fasync_struct *fasync_insert_entry(int fd, struct file *filp, struct fasync_struct **fapp, struct fasync_struct *new) 906 { 907 struct fasync_struct *fa, **fp; 908 909 spin_lock(&filp->f_lock); 910 spin_lock(&fasync_lock); 911 for (fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) { 912 if (fa->fa_file != filp) 913 continue; 914 915 spin_lock_irq(&fa->fa_lock); 916 fa->fa_fd = fd; 917 spin_unlock_irq(&fa->fa_lock); 918 goto out; 919 } 920 921 spin_lock_init(&new->fa_lock); 922 new->magic = FASYNC_MAGIC; 923 new->fa_file = filp; 924 new->fa_fd = fd; 925 new->fa_next = *fapp; 926 rcu_assign_pointer(*fapp, new); 927 filp->f_flags |= FASYNC; 928 929 out: 930 spin_unlock(&fasync_lock); 931 spin_unlock(&filp->f_lock); 932 return fa; 933 } 934 935 /* 936 * Add a fasync entry. Return negative on error, positive if 937 * added, and zero if did nothing but change an existing one. 938 */ 939 static int fasync_add_entry(int fd, struct file *filp, struct fasync_struct **fapp) 940 { 941 struct fasync_struct *new; 942 943 new = fasync_alloc(); 944 if (!new) 945 return -ENOMEM; 946 947 /* 948 * fasync_insert_entry() returns the old (update) entry if 949 * it existed. 950 * 951 * So free the (unused) new entry and return 0 to let the 952 * caller know that we didn't add any new fasync entries. 953 */ 954 if (fasync_insert_entry(fd, filp, fapp, new)) { 955 fasync_free(new); 956 return 0; 957 } 958 959 return 1; 960 } 961 962 /* 963 * fasync_helper() is used by almost all character device drivers 964 * to set up the fasync queue, and for regular files by the file 965 * lease code. It returns negative on error, 0 if it did no changes 966 * and positive if it added/deleted the entry. 967 */ 968 int fasync_helper(int fd, struct file * filp, int on, struct fasync_struct **fapp) 969 { 970 if (!on) 971 return fasync_remove_entry(filp, fapp); 972 return fasync_add_entry(fd, filp, fapp); 973 } 974 975 EXPORT_SYMBOL(fasync_helper); 976 977 /* 978 * rcu_read_lock() is held 979 */ 980 static void kill_fasync_rcu(struct fasync_struct *fa, int sig, int band) 981 { 982 while (fa) { 983 struct fown_struct *fown; 984 unsigned long flags; 985 986 if (fa->magic != FASYNC_MAGIC) { 987 printk(KERN_ERR "kill_fasync: bad magic number in " 988 "fasync_struct!\n"); 989 return; 990 } 991 spin_lock_irqsave(&fa->fa_lock, flags); 992 if (fa->fa_file) { 993 fown = &fa->fa_file->f_owner; 994 /* Don't send SIGURG to processes which have not set a 995 queued signum: SIGURG has its own default signalling 996 mechanism. */ 997 if (!(sig == SIGURG && fown->signum == 0)) 998 send_sigio(fown, fa->fa_fd, band); 999 } 1000 spin_unlock_irqrestore(&fa->fa_lock, flags); 1001 fa = rcu_dereference(fa->fa_next); 1002 } 1003 } 1004 1005 void kill_fasync(struct fasync_struct **fp, int sig, int band) 1006 { 1007 /* First a quick test without locking: usually 1008 * the list is empty. 1009 */ 1010 if (*fp) { 1011 rcu_read_lock(); 1012 kill_fasync_rcu(rcu_dereference(*fp), sig, band); 1013 rcu_read_unlock(); 1014 } 1015 } 1016 EXPORT_SYMBOL(kill_fasync); 1017 1018 static int __init fcntl_init(void) 1019 { 1020 /* 1021 * Please add new bits here to ensure allocation uniqueness. 1022 * Exceptions: O_NONBLOCK is a two bit define on parisc; O_NDELAY 1023 * is defined as O_NONBLOCK on some platforms and not on others. 1024 */ 1025 BUILD_BUG_ON(21 - 1 /* for O_RDONLY being 0 */ != 1026 HWEIGHT32( 1027 (VALID_OPEN_FLAGS & ~(O_NONBLOCK | O_NDELAY)) | 1028 __FMODE_EXEC | __FMODE_NONOTIFY)); 1029 1030 fasync_cache = kmem_cache_create("fasync_cache", 1031 sizeof(struct fasync_struct), 0, SLAB_PANIC, NULL); 1032 return 0; 1033 } 1034 1035 module_init(fcntl_init) 1036