1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * linux/fs/fcntl.c 4 * 5 * Copyright (C) 1991, 1992 Linus Torvalds 6 */ 7 8 #include <linux/syscalls.h> 9 #include <linux/init.h> 10 #include <linux/mm.h> 11 #include <linux/sched/task.h> 12 #include <linux/fs.h> 13 #include <linux/file.h> 14 #include <linux/fdtable.h> 15 #include <linux/capability.h> 16 #include <linux/dnotify.h> 17 #include <linux/slab.h> 18 #include <linux/module.h> 19 #include <linux/pipe_fs_i.h> 20 #include <linux/security.h> 21 #include <linux/ptrace.h> 22 #include <linux/signal.h> 23 #include <linux/rcupdate.h> 24 #include <linux/pid_namespace.h> 25 #include <linux/user_namespace.h> 26 #include <linux/memfd.h> 27 #include <linux/compat.h> 28 #include <linux/mount.h> 29 30 #include <linux/poll.h> 31 #include <asm/siginfo.h> 32 #include <linux/uaccess.h> 33 34 #define SETFL_MASK (O_APPEND | O_NONBLOCK | O_NDELAY | O_DIRECT | O_NOATIME) 35 36 static int setfl(int fd, struct file * filp, unsigned long arg) 37 { 38 struct inode * inode = file_inode(filp); 39 int error = 0; 40 41 /* 42 * O_APPEND cannot be cleared if the file is marked as append-only 43 * and the file is open for write. 44 */ 45 if (((arg ^ filp->f_flags) & O_APPEND) && IS_APPEND(inode)) 46 return -EPERM; 47 48 /* O_NOATIME can only be set by the owner or superuser */ 49 if ((arg & O_NOATIME) && !(filp->f_flags & O_NOATIME)) 50 if (!inode_owner_or_capable(file_mnt_user_ns(filp), inode)) 51 return -EPERM; 52 53 /* required for strict SunOS emulation */ 54 if (O_NONBLOCK != O_NDELAY) 55 if (arg & O_NDELAY) 56 arg |= O_NONBLOCK; 57 58 /* Pipe packetized mode is controlled by O_DIRECT flag */ 59 if (!S_ISFIFO(inode->i_mode) && 60 (arg & O_DIRECT) && 61 !(filp->f_mode & FMODE_CAN_ODIRECT)) 62 return -EINVAL; 63 64 if (filp->f_op->check_flags) 65 error = filp->f_op->check_flags(arg); 66 if (error) 67 return error; 68 69 /* 70 * ->fasync() is responsible for setting the FASYNC bit. 71 */ 72 if (((arg ^ filp->f_flags) & FASYNC) && filp->f_op->fasync) { 73 error = filp->f_op->fasync(fd, filp, (arg & FASYNC) != 0); 74 if (error < 0) 75 goto out; 76 if (error > 0) 77 error = 0; 78 } 79 spin_lock(&filp->f_lock); 80 filp->f_flags = (arg & SETFL_MASK) | (filp->f_flags & ~SETFL_MASK); 81 spin_unlock(&filp->f_lock); 82 83 out: 84 return error; 85 } 86 87 static void f_modown(struct file *filp, struct pid *pid, enum pid_type type, 88 int force) 89 { 90 write_lock_irq(&filp->f_owner.lock); 91 if (force || !filp->f_owner.pid) { 92 put_pid(filp->f_owner.pid); 93 filp->f_owner.pid = get_pid(pid); 94 filp->f_owner.pid_type = type; 95 96 if (pid) { 97 const struct cred *cred = current_cred(); 98 filp->f_owner.uid = cred->uid; 99 filp->f_owner.euid = cred->euid; 100 } 101 } 102 write_unlock_irq(&filp->f_owner.lock); 103 } 104 105 void __f_setown(struct file *filp, struct pid *pid, enum pid_type type, 106 int force) 107 { 108 security_file_set_fowner(filp); 109 f_modown(filp, pid, type, force); 110 } 111 EXPORT_SYMBOL(__f_setown); 112 113 int f_setown(struct file *filp, unsigned long arg, int force) 114 { 115 enum pid_type type; 116 struct pid *pid = NULL; 117 int who = arg, ret = 0; 118 119 type = PIDTYPE_TGID; 120 if (who < 0) { 121 /* avoid overflow below */ 122 if (who == INT_MIN) 123 return -EINVAL; 124 125 type = PIDTYPE_PGID; 126 who = -who; 127 } 128 129 rcu_read_lock(); 130 if (who) { 131 pid = find_vpid(who); 132 if (!pid) 133 ret = -ESRCH; 134 } 135 136 if (!ret) 137 __f_setown(filp, pid, type, force); 138 rcu_read_unlock(); 139 140 return ret; 141 } 142 EXPORT_SYMBOL(f_setown); 143 144 void f_delown(struct file *filp) 145 { 146 f_modown(filp, NULL, PIDTYPE_TGID, 1); 147 } 148 149 pid_t f_getown(struct file *filp) 150 { 151 pid_t pid = 0; 152 153 read_lock_irq(&filp->f_owner.lock); 154 rcu_read_lock(); 155 if (pid_task(filp->f_owner.pid, filp->f_owner.pid_type)) { 156 pid = pid_vnr(filp->f_owner.pid); 157 if (filp->f_owner.pid_type == PIDTYPE_PGID) 158 pid = -pid; 159 } 160 rcu_read_unlock(); 161 read_unlock_irq(&filp->f_owner.lock); 162 return pid; 163 } 164 165 static int f_setown_ex(struct file *filp, unsigned long arg) 166 { 167 struct f_owner_ex __user *owner_p = (void __user *)arg; 168 struct f_owner_ex owner; 169 struct pid *pid; 170 int type; 171 int ret; 172 173 ret = copy_from_user(&owner, owner_p, sizeof(owner)); 174 if (ret) 175 return -EFAULT; 176 177 switch (owner.type) { 178 case F_OWNER_TID: 179 type = PIDTYPE_PID; 180 break; 181 182 case F_OWNER_PID: 183 type = PIDTYPE_TGID; 184 break; 185 186 case F_OWNER_PGRP: 187 type = PIDTYPE_PGID; 188 break; 189 190 default: 191 return -EINVAL; 192 } 193 194 rcu_read_lock(); 195 pid = find_vpid(owner.pid); 196 if (owner.pid && !pid) 197 ret = -ESRCH; 198 else 199 __f_setown(filp, pid, type, 1); 200 rcu_read_unlock(); 201 202 return ret; 203 } 204 205 static int f_getown_ex(struct file *filp, unsigned long arg) 206 { 207 struct f_owner_ex __user *owner_p = (void __user *)arg; 208 struct f_owner_ex owner = {}; 209 int ret = 0; 210 211 read_lock_irq(&filp->f_owner.lock); 212 rcu_read_lock(); 213 if (pid_task(filp->f_owner.pid, filp->f_owner.pid_type)) 214 owner.pid = pid_vnr(filp->f_owner.pid); 215 rcu_read_unlock(); 216 switch (filp->f_owner.pid_type) { 217 case PIDTYPE_PID: 218 owner.type = F_OWNER_TID; 219 break; 220 221 case PIDTYPE_TGID: 222 owner.type = F_OWNER_PID; 223 break; 224 225 case PIDTYPE_PGID: 226 owner.type = F_OWNER_PGRP; 227 break; 228 229 default: 230 WARN_ON(1); 231 ret = -EINVAL; 232 break; 233 } 234 read_unlock_irq(&filp->f_owner.lock); 235 236 if (!ret) { 237 ret = copy_to_user(owner_p, &owner, sizeof(owner)); 238 if (ret) 239 ret = -EFAULT; 240 } 241 return ret; 242 } 243 244 #ifdef CONFIG_CHECKPOINT_RESTORE 245 static int f_getowner_uids(struct file *filp, unsigned long arg) 246 { 247 struct user_namespace *user_ns = current_user_ns(); 248 uid_t __user *dst = (void __user *)arg; 249 uid_t src[2]; 250 int err; 251 252 read_lock_irq(&filp->f_owner.lock); 253 src[0] = from_kuid(user_ns, filp->f_owner.uid); 254 src[1] = from_kuid(user_ns, filp->f_owner.euid); 255 read_unlock_irq(&filp->f_owner.lock); 256 257 err = put_user(src[0], &dst[0]); 258 err |= put_user(src[1], &dst[1]); 259 260 return err; 261 } 262 #else 263 static int f_getowner_uids(struct file *filp, unsigned long arg) 264 { 265 return -EINVAL; 266 } 267 #endif 268 269 static bool rw_hint_valid(enum rw_hint hint) 270 { 271 switch (hint) { 272 case RWH_WRITE_LIFE_NOT_SET: 273 case RWH_WRITE_LIFE_NONE: 274 case RWH_WRITE_LIFE_SHORT: 275 case RWH_WRITE_LIFE_MEDIUM: 276 case RWH_WRITE_LIFE_LONG: 277 case RWH_WRITE_LIFE_EXTREME: 278 return true; 279 default: 280 return false; 281 } 282 } 283 284 static long fcntl_rw_hint(struct file *file, unsigned int cmd, 285 unsigned long arg) 286 { 287 struct inode *inode = file_inode(file); 288 u64 __user *argp = (u64 __user *)arg; 289 enum rw_hint hint; 290 u64 h; 291 292 switch (cmd) { 293 case F_GET_RW_HINT: 294 h = inode->i_write_hint; 295 if (copy_to_user(argp, &h, sizeof(*argp))) 296 return -EFAULT; 297 return 0; 298 case F_SET_RW_HINT: 299 if (copy_from_user(&h, argp, sizeof(h))) 300 return -EFAULT; 301 hint = (enum rw_hint) h; 302 if (!rw_hint_valid(hint)) 303 return -EINVAL; 304 305 inode_lock(inode); 306 inode->i_write_hint = hint; 307 inode_unlock(inode); 308 return 0; 309 default: 310 return -EINVAL; 311 } 312 } 313 314 static long do_fcntl(int fd, unsigned int cmd, unsigned long arg, 315 struct file *filp) 316 { 317 void __user *argp = (void __user *)arg; 318 struct flock flock; 319 long err = -EINVAL; 320 321 switch (cmd) { 322 case F_DUPFD: 323 err = f_dupfd(arg, filp, 0); 324 break; 325 case F_DUPFD_CLOEXEC: 326 err = f_dupfd(arg, filp, O_CLOEXEC); 327 break; 328 case F_GETFD: 329 err = get_close_on_exec(fd) ? FD_CLOEXEC : 0; 330 break; 331 case F_SETFD: 332 err = 0; 333 set_close_on_exec(fd, arg & FD_CLOEXEC); 334 break; 335 case F_GETFL: 336 err = filp->f_flags; 337 break; 338 case F_SETFL: 339 err = setfl(fd, filp, arg); 340 break; 341 #if BITS_PER_LONG != 32 342 /* 32-bit arches must use fcntl64() */ 343 case F_OFD_GETLK: 344 #endif 345 case F_GETLK: 346 if (copy_from_user(&flock, argp, sizeof(flock))) 347 return -EFAULT; 348 err = fcntl_getlk(filp, cmd, &flock); 349 if (!err && copy_to_user(argp, &flock, sizeof(flock))) 350 return -EFAULT; 351 break; 352 #if BITS_PER_LONG != 32 353 /* 32-bit arches must use fcntl64() */ 354 case F_OFD_SETLK: 355 case F_OFD_SETLKW: 356 fallthrough; 357 #endif 358 case F_SETLK: 359 case F_SETLKW: 360 if (copy_from_user(&flock, argp, sizeof(flock))) 361 return -EFAULT; 362 err = fcntl_setlk(fd, filp, cmd, &flock); 363 break; 364 case F_GETOWN: 365 /* 366 * XXX If f_owner is a process group, the 367 * negative return value will get converted 368 * into an error. Oops. If we keep the 369 * current syscall conventions, the only way 370 * to fix this will be in libc. 371 */ 372 err = f_getown(filp); 373 force_successful_syscall_return(); 374 break; 375 case F_SETOWN: 376 err = f_setown(filp, arg, 1); 377 break; 378 case F_GETOWN_EX: 379 err = f_getown_ex(filp, arg); 380 break; 381 case F_SETOWN_EX: 382 err = f_setown_ex(filp, arg); 383 break; 384 case F_GETOWNER_UIDS: 385 err = f_getowner_uids(filp, arg); 386 break; 387 case F_GETSIG: 388 err = filp->f_owner.signum; 389 break; 390 case F_SETSIG: 391 /* arg == 0 restores default behaviour. */ 392 if (!valid_signal(arg)) { 393 break; 394 } 395 err = 0; 396 filp->f_owner.signum = arg; 397 break; 398 case F_GETLEASE: 399 err = fcntl_getlease(filp); 400 break; 401 case F_SETLEASE: 402 err = fcntl_setlease(fd, filp, arg); 403 break; 404 case F_NOTIFY: 405 err = fcntl_dirnotify(fd, filp, arg); 406 break; 407 case F_SETPIPE_SZ: 408 case F_GETPIPE_SZ: 409 err = pipe_fcntl(filp, cmd, arg); 410 break; 411 case F_ADD_SEALS: 412 case F_GET_SEALS: 413 err = memfd_fcntl(filp, cmd, arg); 414 break; 415 case F_GET_RW_HINT: 416 case F_SET_RW_HINT: 417 err = fcntl_rw_hint(filp, cmd, arg); 418 break; 419 default: 420 break; 421 } 422 return err; 423 } 424 425 static int check_fcntl_cmd(unsigned cmd) 426 { 427 switch (cmd) { 428 case F_DUPFD: 429 case F_DUPFD_CLOEXEC: 430 case F_GETFD: 431 case F_SETFD: 432 case F_GETFL: 433 return 1; 434 } 435 return 0; 436 } 437 438 SYSCALL_DEFINE3(fcntl, unsigned int, fd, unsigned int, cmd, unsigned long, arg) 439 { 440 struct fd f = fdget_raw(fd); 441 long err = -EBADF; 442 443 if (!f.file) 444 goto out; 445 446 if (unlikely(f.file->f_mode & FMODE_PATH)) { 447 if (!check_fcntl_cmd(cmd)) 448 goto out1; 449 } 450 451 err = security_file_fcntl(f.file, cmd, arg); 452 if (!err) 453 err = do_fcntl(fd, cmd, arg, f.file); 454 455 out1: 456 fdput(f); 457 out: 458 return err; 459 } 460 461 #if BITS_PER_LONG == 32 462 SYSCALL_DEFINE3(fcntl64, unsigned int, fd, unsigned int, cmd, 463 unsigned long, arg) 464 { 465 void __user *argp = (void __user *)arg; 466 struct fd f = fdget_raw(fd); 467 struct flock64 flock; 468 long err = -EBADF; 469 470 if (!f.file) 471 goto out; 472 473 if (unlikely(f.file->f_mode & FMODE_PATH)) { 474 if (!check_fcntl_cmd(cmd)) 475 goto out1; 476 } 477 478 err = security_file_fcntl(f.file, cmd, arg); 479 if (err) 480 goto out1; 481 482 switch (cmd) { 483 case F_GETLK64: 484 case F_OFD_GETLK: 485 err = -EFAULT; 486 if (copy_from_user(&flock, argp, sizeof(flock))) 487 break; 488 err = fcntl_getlk64(f.file, cmd, &flock); 489 if (!err && copy_to_user(argp, &flock, sizeof(flock))) 490 err = -EFAULT; 491 break; 492 case F_SETLK64: 493 case F_SETLKW64: 494 case F_OFD_SETLK: 495 case F_OFD_SETLKW: 496 err = -EFAULT; 497 if (copy_from_user(&flock, argp, sizeof(flock))) 498 break; 499 err = fcntl_setlk64(fd, f.file, cmd, &flock); 500 break; 501 default: 502 err = do_fcntl(fd, cmd, arg, f.file); 503 break; 504 } 505 out1: 506 fdput(f); 507 out: 508 return err; 509 } 510 #endif 511 512 #ifdef CONFIG_COMPAT 513 /* careful - don't use anywhere else */ 514 #define copy_flock_fields(dst, src) \ 515 (dst)->l_type = (src)->l_type; \ 516 (dst)->l_whence = (src)->l_whence; \ 517 (dst)->l_start = (src)->l_start; \ 518 (dst)->l_len = (src)->l_len; \ 519 (dst)->l_pid = (src)->l_pid; 520 521 static int get_compat_flock(struct flock *kfl, const struct compat_flock __user *ufl) 522 { 523 struct compat_flock fl; 524 525 if (copy_from_user(&fl, ufl, sizeof(struct compat_flock))) 526 return -EFAULT; 527 copy_flock_fields(kfl, &fl); 528 return 0; 529 } 530 531 static int get_compat_flock64(struct flock *kfl, const struct compat_flock64 __user *ufl) 532 { 533 struct compat_flock64 fl; 534 535 if (copy_from_user(&fl, ufl, sizeof(struct compat_flock64))) 536 return -EFAULT; 537 copy_flock_fields(kfl, &fl); 538 return 0; 539 } 540 541 static int put_compat_flock(const struct flock *kfl, struct compat_flock __user *ufl) 542 { 543 struct compat_flock fl; 544 545 memset(&fl, 0, sizeof(struct compat_flock)); 546 copy_flock_fields(&fl, kfl); 547 if (copy_to_user(ufl, &fl, sizeof(struct compat_flock))) 548 return -EFAULT; 549 return 0; 550 } 551 552 static int put_compat_flock64(const struct flock *kfl, struct compat_flock64 __user *ufl) 553 { 554 struct compat_flock64 fl; 555 556 BUILD_BUG_ON(sizeof(kfl->l_start) > sizeof(ufl->l_start)); 557 BUILD_BUG_ON(sizeof(kfl->l_len) > sizeof(ufl->l_len)); 558 559 memset(&fl, 0, sizeof(struct compat_flock64)); 560 copy_flock_fields(&fl, kfl); 561 if (copy_to_user(ufl, &fl, sizeof(struct compat_flock64))) 562 return -EFAULT; 563 return 0; 564 } 565 #undef copy_flock_fields 566 567 static unsigned int 568 convert_fcntl_cmd(unsigned int cmd) 569 { 570 switch (cmd) { 571 case F_GETLK64: 572 return F_GETLK; 573 case F_SETLK64: 574 return F_SETLK; 575 case F_SETLKW64: 576 return F_SETLKW; 577 } 578 579 return cmd; 580 } 581 582 /* 583 * GETLK was successful and we need to return the data, but it needs to fit in 584 * the compat structure. 585 * l_start shouldn't be too big, unless the original start + end is greater than 586 * COMPAT_OFF_T_MAX, in which case the app was asking for trouble, so we return 587 * -EOVERFLOW in that case. l_len could be too big, in which case we just 588 * truncate it, and only allow the app to see that part of the conflicting lock 589 * that might make sense to it anyway 590 */ 591 static int fixup_compat_flock(struct flock *flock) 592 { 593 if (flock->l_start > COMPAT_OFF_T_MAX) 594 return -EOVERFLOW; 595 if (flock->l_len > COMPAT_OFF_T_MAX) 596 flock->l_len = COMPAT_OFF_T_MAX; 597 return 0; 598 } 599 600 static long do_compat_fcntl64(unsigned int fd, unsigned int cmd, 601 compat_ulong_t arg) 602 { 603 struct fd f = fdget_raw(fd); 604 struct flock flock; 605 long err = -EBADF; 606 607 if (!f.file) 608 return err; 609 610 if (unlikely(f.file->f_mode & FMODE_PATH)) { 611 if (!check_fcntl_cmd(cmd)) 612 goto out_put; 613 } 614 615 err = security_file_fcntl(f.file, cmd, arg); 616 if (err) 617 goto out_put; 618 619 switch (cmd) { 620 case F_GETLK: 621 err = get_compat_flock(&flock, compat_ptr(arg)); 622 if (err) 623 break; 624 err = fcntl_getlk(f.file, convert_fcntl_cmd(cmd), &flock); 625 if (err) 626 break; 627 err = fixup_compat_flock(&flock); 628 if (!err) 629 err = put_compat_flock(&flock, compat_ptr(arg)); 630 break; 631 case F_GETLK64: 632 case F_OFD_GETLK: 633 err = get_compat_flock64(&flock, compat_ptr(arg)); 634 if (err) 635 break; 636 err = fcntl_getlk(f.file, convert_fcntl_cmd(cmd), &flock); 637 if (!err) 638 err = put_compat_flock64(&flock, compat_ptr(arg)); 639 break; 640 case F_SETLK: 641 case F_SETLKW: 642 err = get_compat_flock(&flock, compat_ptr(arg)); 643 if (err) 644 break; 645 err = fcntl_setlk(fd, f.file, convert_fcntl_cmd(cmd), &flock); 646 break; 647 case F_SETLK64: 648 case F_SETLKW64: 649 case F_OFD_SETLK: 650 case F_OFD_SETLKW: 651 err = get_compat_flock64(&flock, compat_ptr(arg)); 652 if (err) 653 break; 654 err = fcntl_setlk(fd, f.file, convert_fcntl_cmd(cmd), &flock); 655 break; 656 default: 657 err = do_fcntl(fd, cmd, arg, f.file); 658 break; 659 } 660 out_put: 661 fdput(f); 662 return err; 663 } 664 665 COMPAT_SYSCALL_DEFINE3(fcntl64, unsigned int, fd, unsigned int, cmd, 666 compat_ulong_t, arg) 667 { 668 return do_compat_fcntl64(fd, cmd, arg); 669 } 670 671 COMPAT_SYSCALL_DEFINE3(fcntl, unsigned int, fd, unsigned int, cmd, 672 compat_ulong_t, arg) 673 { 674 switch (cmd) { 675 case F_GETLK64: 676 case F_SETLK64: 677 case F_SETLKW64: 678 case F_OFD_GETLK: 679 case F_OFD_SETLK: 680 case F_OFD_SETLKW: 681 return -EINVAL; 682 } 683 return do_compat_fcntl64(fd, cmd, arg); 684 } 685 #endif 686 687 /* Table to convert sigio signal codes into poll band bitmaps */ 688 689 static const __poll_t band_table[NSIGPOLL] = { 690 EPOLLIN | EPOLLRDNORM, /* POLL_IN */ 691 EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND, /* POLL_OUT */ 692 EPOLLIN | EPOLLRDNORM | EPOLLMSG, /* POLL_MSG */ 693 EPOLLERR, /* POLL_ERR */ 694 EPOLLPRI | EPOLLRDBAND, /* POLL_PRI */ 695 EPOLLHUP | EPOLLERR /* POLL_HUP */ 696 }; 697 698 static inline int sigio_perm(struct task_struct *p, 699 struct fown_struct *fown, int sig) 700 { 701 const struct cred *cred; 702 int ret; 703 704 rcu_read_lock(); 705 cred = __task_cred(p); 706 ret = ((uid_eq(fown->euid, GLOBAL_ROOT_UID) || 707 uid_eq(fown->euid, cred->suid) || uid_eq(fown->euid, cred->uid) || 708 uid_eq(fown->uid, cred->suid) || uid_eq(fown->uid, cred->uid)) && 709 !security_file_send_sigiotask(p, fown, sig)); 710 rcu_read_unlock(); 711 return ret; 712 } 713 714 static void send_sigio_to_task(struct task_struct *p, 715 struct fown_struct *fown, 716 int fd, int reason, enum pid_type type) 717 { 718 /* 719 * F_SETSIG can change ->signum lockless in parallel, make 720 * sure we read it once and use the same value throughout. 721 */ 722 int signum = READ_ONCE(fown->signum); 723 724 if (!sigio_perm(p, fown, signum)) 725 return; 726 727 switch (signum) { 728 default: { 729 kernel_siginfo_t si; 730 731 /* Queue a rt signal with the appropriate fd as its 732 value. We use SI_SIGIO as the source, not 733 SI_KERNEL, since kernel signals always get 734 delivered even if we can't queue. Failure to 735 queue in this case _should_ be reported; we fall 736 back to SIGIO in that case. --sct */ 737 clear_siginfo(&si); 738 si.si_signo = signum; 739 si.si_errno = 0; 740 si.si_code = reason; 741 /* 742 * Posix definies POLL_IN and friends to be signal 743 * specific si_codes for SIG_POLL. Linux extended 744 * these si_codes to other signals in a way that is 745 * ambiguous if other signals also have signal 746 * specific si_codes. In that case use SI_SIGIO instead 747 * to remove the ambiguity. 748 */ 749 if ((signum != SIGPOLL) && sig_specific_sicodes(signum)) 750 si.si_code = SI_SIGIO; 751 752 /* Make sure we are called with one of the POLL_* 753 reasons, otherwise we could leak kernel stack into 754 userspace. */ 755 BUG_ON((reason < POLL_IN) || ((reason - POLL_IN) >= NSIGPOLL)); 756 if (reason - POLL_IN >= NSIGPOLL) 757 si.si_band = ~0L; 758 else 759 si.si_band = mangle_poll(band_table[reason - POLL_IN]); 760 si.si_fd = fd; 761 if (!do_send_sig_info(signum, &si, p, type)) 762 break; 763 } 764 fallthrough; /* fall back on the old plain SIGIO signal */ 765 case 0: 766 do_send_sig_info(SIGIO, SEND_SIG_PRIV, p, type); 767 } 768 } 769 770 void send_sigio(struct fown_struct *fown, int fd, int band) 771 { 772 struct task_struct *p; 773 enum pid_type type; 774 unsigned long flags; 775 struct pid *pid; 776 777 read_lock_irqsave(&fown->lock, flags); 778 779 type = fown->pid_type; 780 pid = fown->pid; 781 if (!pid) 782 goto out_unlock_fown; 783 784 if (type <= PIDTYPE_TGID) { 785 rcu_read_lock(); 786 p = pid_task(pid, PIDTYPE_PID); 787 if (p) 788 send_sigio_to_task(p, fown, fd, band, type); 789 rcu_read_unlock(); 790 } else { 791 read_lock(&tasklist_lock); 792 do_each_pid_task(pid, type, p) { 793 send_sigio_to_task(p, fown, fd, band, type); 794 } while_each_pid_task(pid, type, p); 795 read_unlock(&tasklist_lock); 796 } 797 out_unlock_fown: 798 read_unlock_irqrestore(&fown->lock, flags); 799 } 800 801 static void send_sigurg_to_task(struct task_struct *p, 802 struct fown_struct *fown, enum pid_type type) 803 { 804 if (sigio_perm(p, fown, SIGURG)) 805 do_send_sig_info(SIGURG, SEND_SIG_PRIV, p, type); 806 } 807 808 int send_sigurg(struct fown_struct *fown) 809 { 810 struct task_struct *p; 811 enum pid_type type; 812 struct pid *pid; 813 unsigned long flags; 814 int ret = 0; 815 816 read_lock_irqsave(&fown->lock, flags); 817 818 type = fown->pid_type; 819 pid = fown->pid; 820 if (!pid) 821 goto out_unlock_fown; 822 823 ret = 1; 824 825 if (type <= PIDTYPE_TGID) { 826 rcu_read_lock(); 827 p = pid_task(pid, PIDTYPE_PID); 828 if (p) 829 send_sigurg_to_task(p, fown, type); 830 rcu_read_unlock(); 831 } else { 832 read_lock(&tasklist_lock); 833 do_each_pid_task(pid, type, p) { 834 send_sigurg_to_task(p, fown, type); 835 } while_each_pid_task(pid, type, p); 836 read_unlock(&tasklist_lock); 837 } 838 out_unlock_fown: 839 read_unlock_irqrestore(&fown->lock, flags); 840 return ret; 841 } 842 843 static DEFINE_SPINLOCK(fasync_lock); 844 static struct kmem_cache *fasync_cache __read_mostly; 845 846 static void fasync_free_rcu(struct rcu_head *head) 847 { 848 kmem_cache_free(fasync_cache, 849 container_of(head, struct fasync_struct, fa_rcu)); 850 } 851 852 /* 853 * Remove a fasync entry. If successfully removed, return 854 * positive and clear the FASYNC flag. If no entry exists, 855 * do nothing and return 0. 856 * 857 * NOTE! It is very important that the FASYNC flag always 858 * match the state "is the filp on a fasync list". 859 * 860 */ 861 int fasync_remove_entry(struct file *filp, struct fasync_struct **fapp) 862 { 863 struct fasync_struct *fa, **fp; 864 int result = 0; 865 866 spin_lock(&filp->f_lock); 867 spin_lock(&fasync_lock); 868 for (fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) { 869 if (fa->fa_file != filp) 870 continue; 871 872 write_lock_irq(&fa->fa_lock); 873 fa->fa_file = NULL; 874 write_unlock_irq(&fa->fa_lock); 875 876 *fp = fa->fa_next; 877 call_rcu(&fa->fa_rcu, fasync_free_rcu); 878 filp->f_flags &= ~FASYNC; 879 result = 1; 880 break; 881 } 882 spin_unlock(&fasync_lock); 883 spin_unlock(&filp->f_lock); 884 return result; 885 } 886 887 struct fasync_struct *fasync_alloc(void) 888 { 889 return kmem_cache_alloc(fasync_cache, GFP_KERNEL); 890 } 891 892 /* 893 * NOTE! This can be used only for unused fasync entries: 894 * entries that actually got inserted on the fasync list 895 * need to be released by rcu - see fasync_remove_entry. 896 */ 897 void fasync_free(struct fasync_struct *new) 898 { 899 kmem_cache_free(fasync_cache, new); 900 } 901 902 /* 903 * Insert a new entry into the fasync list. Return the pointer to the 904 * old one if we didn't use the new one. 905 * 906 * NOTE! It is very important that the FASYNC flag always 907 * match the state "is the filp on a fasync list". 908 */ 909 struct fasync_struct *fasync_insert_entry(int fd, struct file *filp, struct fasync_struct **fapp, struct fasync_struct *new) 910 { 911 struct fasync_struct *fa, **fp; 912 913 spin_lock(&filp->f_lock); 914 spin_lock(&fasync_lock); 915 for (fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) { 916 if (fa->fa_file != filp) 917 continue; 918 919 write_lock_irq(&fa->fa_lock); 920 fa->fa_fd = fd; 921 write_unlock_irq(&fa->fa_lock); 922 goto out; 923 } 924 925 rwlock_init(&new->fa_lock); 926 new->magic = FASYNC_MAGIC; 927 new->fa_file = filp; 928 new->fa_fd = fd; 929 new->fa_next = *fapp; 930 rcu_assign_pointer(*fapp, new); 931 filp->f_flags |= FASYNC; 932 933 out: 934 spin_unlock(&fasync_lock); 935 spin_unlock(&filp->f_lock); 936 return fa; 937 } 938 939 /* 940 * Add a fasync entry. Return negative on error, positive if 941 * added, and zero if did nothing but change an existing one. 942 */ 943 static int fasync_add_entry(int fd, struct file *filp, struct fasync_struct **fapp) 944 { 945 struct fasync_struct *new; 946 947 new = fasync_alloc(); 948 if (!new) 949 return -ENOMEM; 950 951 /* 952 * fasync_insert_entry() returns the old (update) entry if 953 * it existed. 954 * 955 * So free the (unused) new entry and return 0 to let the 956 * caller know that we didn't add any new fasync entries. 957 */ 958 if (fasync_insert_entry(fd, filp, fapp, new)) { 959 fasync_free(new); 960 return 0; 961 } 962 963 return 1; 964 } 965 966 /* 967 * fasync_helper() is used by almost all character device drivers 968 * to set up the fasync queue, and for regular files by the file 969 * lease code. It returns negative on error, 0 if it did no changes 970 * and positive if it added/deleted the entry. 971 */ 972 int fasync_helper(int fd, struct file * filp, int on, struct fasync_struct **fapp) 973 { 974 if (!on) 975 return fasync_remove_entry(filp, fapp); 976 return fasync_add_entry(fd, filp, fapp); 977 } 978 979 EXPORT_SYMBOL(fasync_helper); 980 981 /* 982 * rcu_read_lock() is held 983 */ 984 static void kill_fasync_rcu(struct fasync_struct *fa, int sig, int band) 985 { 986 while (fa) { 987 struct fown_struct *fown; 988 unsigned long flags; 989 990 if (fa->magic != FASYNC_MAGIC) { 991 printk(KERN_ERR "kill_fasync: bad magic number in " 992 "fasync_struct!\n"); 993 return; 994 } 995 read_lock_irqsave(&fa->fa_lock, flags); 996 if (fa->fa_file) { 997 fown = &fa->fa_file->f_owner; 998 /* Don't send SIGURG to processes which have not set a 999 queued signum: SIGURG has its own default signalling 1000 mechanism. */ 1001 if (!(sig == SIGURG && fown->signum == 0)) 1002 send_sigio(fown, fa->fa_fd, band); 1003 } 1004 read_unlock_irqrestore(&fa->fa_lock, flags); 1005 fa = rcu_dereference(fa->fa_next); 1006 } 1007 } 1008 1009 void kill_fasync(struct fasync_struct **fp, int sig, int band) 1010 { 1011 /* First a quick test without locking: usually 1012 * the list is empty. 1013 */ 1014 if (*fp) { 1015 rcu_read_lock(); 1016 kill_fasync_rcu(rcu_dereference(*fp), sig, band); 1017 rcu_read_unlock(); 1018 } 1019 } 1020 EXPORT_SYMBOL(kill_fasync); 1021 1022 static int __init fcntl_init(void) 1023 { 1024 /* 1025 * Please add new bits here to ensure allocation uniqueness. 1026 * Exceptions: O_NONBLOCK is a two bit define on parisc; O_NDELAY 1027 * is defined as O_NONBLOCK on some platforms and not on others. 1028 */ 1029 BUILD_BUG_ON(21 - 1 /* for O_RDONLY being 0 */ != 1030 HWEIGHT32( 1031 (VALID_OPEN_FLAGS & ~(O_NONBLOCK | O_NDELAY)) | 1032 __FMODE_EXEC | __FMODE_NONOTIFY)); 1033 1034 fasync_cache = kmem_cache_create("fasync_cache", 1035 sizeof(struct fasync_struct), 0, 1036 SLAB_PANIC | SLAB_ACCOUNT, NULL); 1037 return 0; 1038 } 1039 1040 module_init(fcntl_init) 1041