1 /*- 2 * Copyright (c) 2002 Alfred Perlstein <alfred@FreeBSD.org> 3 * Copyright (c) 2003-2005 SPARTA, Inc. 4 * Copyright (c) 2005 Robert N. M. Watson 5 * All rights reserved. 6 * 7 * This software was developed for the FreeBSD Project in part by Network 8 * Associates Laboratories, the Security Research Division of Network 9 * Associates, Inc. under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), 10 * as part of the DARPA CHATS research program. 11 * 12 * Redistribution and use in source and binary forms, with or without 13 * modification, are permitted provided that the following conditions 14 * are met: 15 * 1. Redistributions of source code must retain the above copyright 16 * notice, this list of conditions and the following disclaimer. 17 * 2. Redistributions in binary form must reproduce the above copyright 18 * notice, this list of conditions and the following disclaimer in the 19 * documentation and/or other materials provided with the distribution. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 */ 33 34 #include <sys/cdefs.h> 35 __FBSDID("$FreeBSD$"); 36 37 #include "opt_compat.h" 38 #include "opt_posix.h" 39 40 #include <sys/param.h> 41 #include <sys/capability.h> 42 #include <sys/condvar.h> 43 #include <sys/fcntl.h> 44 #include <sys/file.h> 45 #include <sys/filedesc.h> 46 #include <sys/fnv_hash.h> 47 #include <sys/kernel.h> 48 #include <sys/ksem.h> 49 #include <sys/lock.h> 50 #include <sys/malloc.h> 51 #include <sys/module.h> 52 #include <sys/mutex.h> 53 #include <sys/priv.h> 54 #include <sys/proc.h> 55 #include <sys/posix4.h> 56 #include <sys/_semaphore.h> 57 #include <sys/stat.h> 58 #include <sys/syscall.h> 59 #include <sys/syscallsubr.h> 60 #include <sys/sysctl.h> 61 #include <sys/sysent.h> 62 #include <sys/sysproto.h> 63 #include <sys/systm.h> 64 #include <sys/sx.h> 65 #include <sys/vnode.h> 66 67 #include <security/mac/mac_framework.h> 68 69 FEATURE(p1003_1b_semaphores, "POSIX P1003.1B semaphores support"); 70 /* 71 * TODO 72 * 73 * - Resource limits? 74 * - Replace global sem_lock with mtx_pool locks? 75 * - Add a MAC check_create() hook for creating new named semaphores. 76 */ 77 78 #ifndef SEM_MAX 79 #define SEM_MAX 30 80 #endif 81 82 #ifdef SEM_DEBUG 83 #define DP(x) printf x 84 #else 85 #define DP(x) 86 #endif 87 88 struct ksem_mapping { 89 char *km_path; 90 Fnv32_t km_fnv; 91 struct ksem *km_ksem; 92 LIST_ENTRY(ksem_mapping) km_link; 93 }; 94 95 static MALLOC_DEFINE(M_KSEM, "ksem", "semaphore file descriptor"); 96 static LIST_HEAD(, ksem_mapping) *ksem_dictionary; 97 static struct sx ksem_dict_lock; 98 static struct mtx ksem_count_lock; 99 static struct mtx sem_lock; 100 static u_long ksem_hash; 101 static int ksem_dead; 102 103 #define KSEM_HASH(fnv) (&ksem_dictionary[(fnv) & ksem_hash]) 104 105 static int nsems = 0; 106 SYSCTL_DECL(_p1003_1b); 107 SYSCTL_INT(_p1003_1b, OID_AUTO, nsems, CTLFLAG_RD, &nsems, 0, 108 "Number of active kernel POSIX semaphores"); 109 110 static int kern_sem_wait(struct thread *td, semid_t id, int tryflag, 111 struct timespec *abstime); 112 static int ksem_access(struct ksem *ks, struct ucred *ucred); 113 static struct ksem *ksem_alloc(struct ucred *ucred, mode_t mode, 114 unsigned int value); 115 static int ksem_create(struct thread *td, const char *path, 116 semid_t *semidp, mode_t mode, unsigned int value, 117 int flags, int compat32); 118 static void ksem_drop(struct ksem *ks); 119 static int ksem_get(struct thread *td, semid_t id, cap_rights_t rights, 120 struct file **fpp); 121 static struct ksem *ksem_hold(struct ksem *ks); 122 static void ksem_insert(char *path, Fnv32_t fnv, struct ksem *ks); 123 static struct ksem *ksem_lookup(char *path, Fnv32_t fnv); 124 static void ksem_module_destroy(void); 125 static int ksem_module_init(void); 126 static int ksem_remove(char *path, Fnv32_t fnv, struct ucred *ucred); 127 static int sem_modload(struct module *module, int cmd, void *arg); 128 129 static fo_rdwr_t ksem_read; 130 static fo_rdwr_t ksem_write; 131 static fo_truncate_t ksem_truncate; 132 static fo_ioctl_t ksem_ioctl; 133 static fo_poll_t ksem_poll; 134 static fo_kqfilter_t ksem_kqfilter; 135 static fo_stat_t ksem_stat; 136 static fo_close_t ksem_closef; 137 static fo_chmod_t ksem_chmod; 138 static fo_chown_t ksem_chown; 139 140 /* File descriptor operations. */ 141 static struct fileops ksem_ops = { 142 .fo_read = ksem_read, 143 .fo_write = ksem_write, 144 .fo_truncate = ksem_truncate, 145 .fo_ioctl = ksem_ioctl, 146 .fo_poll = ksem_poll, 147 .fo_kqfilter = ksem_kqfilter, 148 .fo_stat = ksem_stat, 149 .fo_close = ksem_closef, 150 .fo_chmod = ksem_chmod, 151 .fo_chown = ksem_chown, 152 .fo_sendfile = invfo_sendfile, 153 .fo_flags = DFLAG_PASSABLE 154 }; 155 156 FEATURE(posix_sem, "POSIX semaphores"); 157 158 static int 159 ksem_read(struct file *fp, struct uio *uio, struct ucred *active_cred, 160 int flags, struct thread *td) 161 { 162 163 return (EOPNOTSUPP); 164 } 165 166 static int 167 ksem_write(struct file *fp, struct uio *uio, struct ucred *active_cred, 168 int flags, struct thread *td) 169 { 170 171 return (EOPNOTSUPP); 172 } 173 174 static int 175 ksem_truncate(struct file *fp, off_t length, struct ucred *active_cred, 176 struct thread *td) 177 { 178 179 return (EINVAL); 180 } 181 182 static int 183 ksem_ioctl(struct file *fp, u_long com, void *data, 184 struct ucred *active_cred, struct thread *td) 185 { 186 187 return (EOPNOTSUPP); 188 } 189 190 static int 191 ksem_poll(struct file *fp, int events, struct ucred *active_cred, 192 struct thread *td) 193 { 194 195 return (EOPNOTSUPP); 196 } 197 198 static int 199 ksem_kqfilter(struct file *fp, struct knote *kn) 200 { 201 202 return (EOPNOTSUPP); 203 } 204 205 static int 206 ksem_stat(struct file *fp, struct stat *sb, struct ucred *active_cred, 207 struct thread *td) 208 { 209 struct ksem *ks; 210 #ifdef MAC 211 int error; 212 #endif 213 214 ks = fp->f_data; 215 216 #ifdef MAC 217 error = mac_posixsem_check_stat(active_cred, fp->f_cred, ks); 218 if (error) 219 return (error); 220 #endif 221 222 /* 223 * Attempt to return sanish values for fstat() on a semaphore 224 * file descriptor. 225 */ 226 bzero(sb, sizeof(*sb)); 227 228 mtx_lock(&sem_lock); 229 sb->st_atim = ks->ks_atime; 230 sb->st_ctim = ks->ks_ctime; 231 sb->st_mtim = ks->ks_mtime; 232 sb->st_birthtim = ks->ks_birthtime; 233 sb->st_uid = ks->ks_uid; 234 sb->st_gid = ks->ks_gid; 235 sb->st_mode = S_IFREG | ks->ks_mode; /* XXX */ 236 mtx_unlock(&sem_lock); 237 238 return (0); 239 } 240 241 static int 242 ksem_chmod(struct file *fp, mode_t mode, struct ucred *active_cred, 243 struct thread *td) 244 { 245 struct ksem *ks; 246 int error; 247 248 error = 0; 249 ks = fp->f_data; 250 mtx_lock(&sem_lock); 251 #ifdef MAC 252 error = mac_posixsem_check_setmode(active_cred, ks, mode); 253 if (error != 0) 254 goto out; 255 #endif 256 error = vaccess(VREG, ks->ks_mode, ks->ks_uid, ks->ks_gid, VADMIN, 257 active_cred, NULL); 258 if (error != 0) 259 goto out; 260 ks->ks_mode = mode & ACCESSPERMS; 261 out: 262 mtx_unlock(&sem_lock); 263 return (error); 264 } 265 266 static int 267 ksem_chown(struct file *fp, uid_t uid, gid_t gid, struct ucred *active_cred, 268 struct thread *td) 269 { 270 struct ksem *ks; 271 int error; 272 273 error = 0; 274 ks = fp->f_data; 275 mtx_lock(&sem_lock); 276 #ifdef MAC 277 error = mac_posixsem_check_setowner(active_cred, ks, uid, gid); 278 if (error != 0) 279 goto out; 280 #endif 281 if (uid == (uid_t)-1) 282 uid = ks->ks_uid; 283 if (gid == (gid_t)-1) 284 gid = ks->ks_gid; 285 if (((uid != ks->ks_uid && uid != active_cred->cr_uid) || 286 (gid != ks->ks_gid && !groupmember(gid, active_cred))) && 287 (error = priv_check_cred(active_cred, PRIV_VFS_CHOWN, 0))) 288 goto out; 289 ks->ks_uid = uid; 290 ks->ks_gid = gid; 291 out: 292 mtx_unlock(&sem_lock); 293 return (error); 294 } 295 296 static int 297 ksem_closef(struct file *fp, struct thread *td) 298 { 299 struct ksem *ks; 300 301 ks = fp->f_data; 302 fp->f_data = NULL; 303 ksem_drop(ks); 304 305 return (0); 306 } 307 308 /* 309 * ksem object management including creation and reference counting 310 * routines. 311 */ 312 static struct ksem * 313 ksem_alloc(struct ucred *ucred, mode_t mode, unsigned int value) 314 { 315 struct ksem *ks; 316 317 mtx_lock(&ksem_count_lock); 318 if (nsems == p31b_getcfg(CTL_P1003_1B_SEM_NSEMS_MAX) || ksem_dead) { 319 mtx_unlock(&ksem_count_lock); 320 return (NULL); 321 } 322 nsems++; 323 mtx_unlock(&ksem_count_lock); 324 ks = malloc(sizeof(*ks), M_KSEM, M_WAITOK | M_ZERO); 325 ks->ks_uid = ucred->cr_uid; 326 ks->ks_gid = ucred->cr_gid; 327 ks->ks_mode = mode; 328 ks->ks_value = value; 329 cv_init(&ks->ks_cv, "ksem"); 330 vfs_timestamp(&ks->ks_birthtime); 331 ks->ks_atime = ks->ks_mtime = ks->ks_ctime = ks->ks_birthtime; 332 refcount_init(&ks->ks_ref, 1); 333 #ifdef MAC 334 mac_posixsem_init(ks); 335 mac_posixsem_create(ucred, ks); 336 #endif 337 338 return (ks); 339 } 340 341 static struct ksem * 342 ksem_hold(struct ksem *ks) 343 { 344 345 refcount_acquire(&ks->ks_ref); 346 return (ks); 347 } 348 349 static void 350 ksem_drop(struct ksem *ks) 351 { 352 353 if (refcount_release(&ks->ks_ref)) { 354 #ifdef MAC 355 mac_posixsem_destroy(ks); 356 #endif 357 cv_destroy(&ks->ks_cv); 358 free(ks, M_KSEM); 359 mtx_lock(&ksem_count_lock); 360 nsems--; 361 mtx_unlock(&ksem_count_lock); 362 } 363 } 364 365 /* 366 * Determine if the credentials have sufficient permissions for read 367 * and write access. 368 */ 369 static int 370 ksem_access(struct ksem *ks, struct ucred *ucred) 371 { 372 int error; 373 374 error = vaccess(VREG, ks->ks_mode, ks->ks_uid, ks->ks_gid, 375 VREAD | VWRITE, ucred, NULL); 376 if (error) 377 error = priv_check_cred(ucred, PRIV_SEM_WRITE, 0); 378 return (error); 379 } 380 381 /* 382 * Dictionary management. We maintain an in-kernel dictionary to map 383 * paths to semaphore objects. We use the FNV hash on the path to 384 * store the mappings in a hash table. 385 */ 386 static struct ksem * 387 ksem_lookup(char *path, Fnv32_t fnv) 388 { 389 struct ksem_mapping *map; 390 391 LIST_FOREACH(map, KSEM_HASH(fnv), km_link) { 392 if (map->km_fnv != fnv) 393 continue; 394 if (strcmp(map->km_path, path) == 0) 395 return (map->km_ksem); 396 } 397 398 return (NULL); 399 } 400 401 static void 402 ksem_insert(char *path, Fnv32_t fnv, struct ksem *ks) 403 { 404 struct ksem_mapping *map; 405 406 map = malloc(sizeof(struct ksem_mapping), M_KSEM, M_WAITOK); 407 map->km_path = path; 408 map->km_fnv = fnv; 409 map->km_ksem = ksem_hold(ks); 410 ks->ks_path = path; 411 LIST_INSERT_HEAD(KSEM_HASH(fnv), map, km_link); 412 } 413 414 static int 415 ksem_remove(char *path, Fnv32_t fnv, struct ucred *ucred) 416 { 417 struct ksem_mapping *map; 418 int error; 419 420 LIST_FOREACH(map, KSEM_HASH(fnv), km_link) { 421 if (map->km_fnv != fnv) 422 continue; 423 if (strcmp(map->km_path, path) == 0) { 424 #ifdef MAC 425 error = mac_posixsem_check_unlink(ucred, map->km_ksem); 426 if (error) 427 return (error); 428 #endif 429 error = ksem_access(map->km_ksem, ucred); 430 if (error) 431 return (error); 432 map->km_ksem->ks_path = NULL; 433 LIST_REMOVE(map, km_link); 434 ksem_drop(map->km_ksem); 435 free(map->km_path, M_KSEM); 436 free(map, M_KSEM); 437 return (0); 438 } 439 } 440 441 return (ENOENT); 442 } 443 444 static void 445 ksem_info_impl(struct ksem *ks, char *path, size_t size, uint32_t *value) 446 { 447 448 if (ks->ks_path == NULL) 449 return; 450 sx_slock(&ksem_dict_lock); 451 if (ks->ks_path != NULL) 452 strlcpy(path, ks->ks_path, size); 453 if (value != NULL) 454 *value = ks->ks_value; 455 sx_sunlock(&ksem_dict_lock); 456 } 457 458 static int 459 ksem_create_copyout_semid(struct thread *td, semid_t *semidp, int fd, 460 int compat32) 461 { 462 semid_t semid; 463 #ifdef COMPAT_FREEBSD32 464 int32_t semid32; 465 #endif 466 void *ptr; 467 size_t ptrs; 468 469 #ifdef COMPAT_FREEBSD32 470 if (compat32) { 471 semid32 = fd; 472 ptr = &semid32; 473 ptrs = sizeof(semid32); 474 } else { 475 #endif 476 semid = fd; 477 ptr = &semid; 478 ptrs = sizeof(semid); 479 compat32 = 0; /* silence gcc */ 480 #ifdef COMPAT_FREEBSD32 481 } 482 #endif 483 484 return (copyout(ptr, semidp, ptrs)); 485 } 486 487 /* Other helper routines. */ 488 static int 489 ksem_create(struct thread *td, const char *name, semid_t *semidp, mode_t mode, 490 unsigned int value, int flags, int compat32) 491 { 492 struct filedesc *fdp; 493 struct ksem *ks; 494 struct file *fp; 495 char *path; 496 Fnv32_t fnv; 497 int error, fd; 498 499 if (value > SEM_VALUE_MAX) 500 return (EINVAL); 501 502 fdp = td->td_proc->p_fd; 503 mode = (mode & ~fdp->fd_cmask) & ACCESSPERMS; 504 error = falloc(td, &fp, &fd, O_CLOEXEC); 505 if (error) { 506 if (name == NULL) 507 error = ENOSPC; 508 return (error); 509 } 510 511 /* 512 * Go ahead and copyout the file descriptor now. This is a bit 513 * premature, but it is a lot easier to handle errors as opposed 514 * to later when we've possibly created a new semaphore, etc. 515 */ 516 error = ksem_create_copyout_semid(td, semidp, fd, compat32); 517 if (error) { 518 fdclose(fdp, fp, fd, td); 519 fdrop(fp, td); 520 return (error); 521 } 522 523 if (name == NULL) { 524 /* Create an anonymous semaphore. */ 525 ks = ksem_alloc(td->td_ucred, mode, value); 526 if (ks == NULL) 527 error = ENOSPC; 528 else 529 ks->ks_flags |= KS_ANONYMOUS; 530 } else { 531 path = malloc(MAXPATHLEN, M_KSEM, M_WAITOK); 532 error = copyinstr(name, path, MAXPATHLEN, NULL); 533 534 /* Require paths to start with a '/' character. */ 535 if (error == 0 && path[0] != '/') 536 error = EINVAL; 537 if (error) { 538 fdclose(fdp, fp, fd, td); 539 fdrop(fp, td); 540 free(path, M_KSEM); 541 return (error); 542 } 543 544 fnv = fnv_32_str(path, FNV1_32_INIT); 545 sx_xlock(&ksem_dict_lock); 546 ks = ksem_lookup(path, fnv); 547 if (ks == NULL) { 548 /* Object does not exist, create it if requested. */ 549 if (flags & O_CREAT) { 550 ks = ksem_alloc(td->td_ucred, mode, value); 551 if (ks == NULL) 552 error = ENFILE; 553 else { 554 ksem_insert(path, fnv, ks); 555 path = NULL; 556 } 557 } else 558 error = ENOENT; 559 } else { 560 /* 561 * Object already exists, obtain a new 562 * reference if requested and permitted. 563 */ 564 if ((flags & (O_CREAT | O_EXCL)) == 565 (O_CREAT | O_EXCL)) 566 error = EEXIST; 567 else { 568 #ifdef MAC 569 error = mac_posixsem_check_open(td->td_ucred, 570 ks); 571 if (error == 0) 572 #endif 573 error = ksem_access(ks, td->td_ucred); 574 } 575 if (error == 0) 576 ksem_hold(ks); 577 #ifdef INVARIANTS 578 else 579 ks = NULL; 580 #endif 581 } 582 sx_xunlock(&ksem_dict_lock); 583 if (path) 584 free(path, M_KSEM); 585 } 586 587 if (error) { 588 KASSERT(ks == NULL, ("ksem_create error with a ksem")); 589 fdclose(fdp, fp, fd, td); 590 fdrop(fp, td); 591 return (error); 592 } 593 KASSERT(ks != NULL, ("ksem_create w/o a ksem")); 594 595 finit(fp, FREAD | FWRITE, DTYPE_SEM, ks, &ksem_ops); 596 597 fdrop(fp, td); 598 599 return (0); 600 } 601 602 static int 603 ksem_get(struct thread *td, semid_t id, cap_rights_t rights, struct file **fpp) 604 { 605 struct ksem *ks; 606 struct file *fp; 607 int error; 608 609 error = fget(td, id, rights, &fp); 610 if (error) 611 return (EINVAL); 612 if (fp->f_type != DTYPE_SEM) { 613 fdrop(fp, td); 614 return (EINVAL); 615 } 616 ks = fp->f_data; 617 if (ks->ks_flags & KS_DEAD) { 618 fdrop(fp, td); 619 return (EINVAL); 620 } 621 *fpp = fp; 622 return (0); 623 } 624 625 /* System calls. */ 626 #ifndef _SYS_SYSPROTO_H_ 627 struct ksem_init_args { 628 unsigned int value; 629 semid_t *idp; 630 }; 631 #endif 632 int 633 sys_ksem_init(struct thread *td, struct ksem_init_args *uap) 634 { 635 636 return (ksem_create(td, NULL, uap->idp, S_IRWXU | S_IRWXG, uap->value, 637 0, 0)); 638 } 639 640 #ifndef _SYS_SYSPROTO_H_ 641 struct ksem_open_args { 642 char *name; 643 int oflag; 644 mode_t mode; 645 unsigned int value; 646 semid_t *idp; 647 }; 648 #endif 649 int 650 sys_ksem_open(struct thread *td, struct ksem_open_args *uap) 651 { 652 653 DP((">>> ksem_open start, pid=%d\n", (int)td->td_proc->p_pid)); 654 655 if ((uap->oflag & ~(O_CREAT | O_EXCL)) != 0) 656 return (EINVAL); 657 return (ksem_create(td, uap->name, uap->idp, uap->mode, uap->value, 658 uap->oflag, 0)); 659 } 660 661 #ifndef _SYS_SYSPROTO_H_ 662 struct ksem_unlink_args { 663 char *name; 664 }; 665 #endif 666 int 667 sys_ksem_unlink(struct thread *td, struct ksem_unlink_args *uap) 668 { 669 char *path; 670 Fnv32_t fnv; 671 int error; 672 673 path = malloc(MAXPATHLEN, M_TEMP, M_WAITOK); 674 error = copyinstr(uap->name, path, MAXPATHLEN, NULL); 675 if (error) { 676 free(path, M_TEMP); 677 return (error); 678 } 679 680 fnv = fnv_32_str(path, FNV1_32_INIT); 681 sx_xlock(&ksem_dict_lock); 682 error = ksem_remove(path, fnv, td->td_ucred); 683 sx_xunlock(&ksem_dict_lock); 684 free(path, M_TEMP); 685 686 return (error); 687 } 688 689 #ifndef _SYS_SYSPROTO_H_ 690 struct ksem_close_args { 691 semid_t id; 692 }; 693 #endif 694 int 695 sys_ksem_close(struct thread *td, struct ksem_close_args *uap) 696 { 697 struct ksem *ks; 698 struct file *fp; 699 int error; 700 701 /* No capability rights required to close a semaphore. */ 702 error = ksem_get(td, uap->id, 0, &fp); 703 if (error) 704 return (error); 705 ks = fp->f_data; 706 if (ks->ks_flags & KS_ANONYMOUS) { 707 fdrop(fp, td); 708 return (EINVAL); 709 } 710 error = kern_close(td, uap->id); 711 fdrop(fp, td); 712 return (error); 713 } 714 715 #ifndef _SYS_SYSPROTO_H_ 716 struct ksem_post_args { 717 semid_t id; 718 }; 719 #endif 720 int 721 sys_ksem_post(struct thread *td, struct ksem_post_args *uap) 722 { 723 struct file *fp; 724 struct ksem *ks; 725 int error; 726 727 error = ksem_get(td, uap->id, CAP_SEM_POST, &fp); 728 if (error) 729 return (error); 730 ks = fp->f_data; 731 732 mtx_lock(&sem_lock); 733 #ifdef MAC 734 error = mac_posixsem_check_post(td->td_ucred, fp->f_cred, ks); 735 if (error) 736 goto err; 737 #endif 738 if (ks->ks_value == SEM_VALUE_MAX) { 739 error = EOVERFLOW; 740 goto err; 741 } 742 ++ks->ks_value; 743 if (ks->ks_waiters > 0) 744 cv_signal(&ks->ks_cv); 745 error = 0; 746 vfs_timestamp(&ks->ks_ctime); 747 err: 748 mtx_unlock(&sem_lock); 749 fdrop(fp, td); 750 return (error); 751 } 752 753 #ifndef _SYS_SYSPROTO_H_ 754 struct ksem_wait_args { 755 semid_t id; 756 }; 757 #endif 758 int 759 sys_ksem_wait(struct thread *td, struct ksem_wait_args *uap) 760 { 761 762 return (kern_sem_wait(td, uap->id, 0, NULL)); 763 } 764 765 #ifndef _SYS_SYSPROTO_H_ 766 struct ksem_timedwait_args { 767 semid_t id; 768 const struct timespec *abstime; 769 }; 770 #endif 771 int 772 sys_ksem_timedwait(struct thread *td, struct ksem_timedwait_args *uap) 773 { 774 struct timespec abstime; 775 struct timespec *ts; 776 int error; 777 778 /* 779 * We allow a null timespec (wait forever). 780 */ 781 if (uap->abstime == NULL) 782 ts = NULL; 783 else { 784 error = copyin(uap->abstime, &abstime, sizeof(abstime)); 785 if (error != 0) 786 return (error); 787 if (abstime.tv_nsec >= 1000000000 || abstime.tv_nsec < 0) 788 return (EINVAL); 789 ts = &abstime; 790 } 791 return (kern_sem_wait(td, uap->id, 0, ts)); 792 } 793 794 #ifndef _SYS_SYSPROTO_H_ 795 struct ksem_trywait_args { 796 semid_t id; 797 }; 798 #endif 799 int 800 sys_ksem_trywait(struct thread *td, struct ksem_trywait_args *uap) 801 { 802 803 return (kern_sem_wait(td, uap->id, 1, NULL)); 804 } 805 806 static int 807 kern_sem_wait(struct thread *td, semid_t id, int tryflag, 808 struct timespec *abstime) 809 { 810 struct timespec ts1, ts2; 811 struct timeval tv; 812 struct file *fp; 813 struct ksem *ks; 814 int error; 815 816 DP((">>> kern_sem_wait entered! pid=%d\n", (int)td->td_proc->p_pid)); 817 error = ksem_get(td, id, CAP_SEM_WAIT, &fp); 818 if (error) 819 return (error); 820 ks = fp->f_data; 821 mtx_lock(&sem_lock); 822 DP((">>> kern_sem_wait critical section entered! pid=%d\n", 823 (int)td->td_proc->p_pid)); 824 #ifdef MAC 825 error = mac_posixsem_check_wait(td->td_ucred, fp->f_cred, ks); 826 if (error) { 827 DP(("kern_sem_wait mac failed\n")); 828 goto err; 829 } 830 #endif 831 DP(("kern_sem_wait value = %d, tryflag %d\n", ks->ks_value, tryflag)); 832 vfs_timestamp(&ks->ks_atime); 833 while (ks->ks_value == 0) { 834 ks->ks_waiters++; 835 if (tryflag != 0) 836 error = EAGAIN; 837 else if (abstime == NULL) 838 error = cv_wait_sig(&ks->ks_cv, &sem_lock); 839 else { 840 for (;;) { 841 ts1 = *abstime; 842 getnanotime(&ts2); 843 timespecsub(&ts1, &ts2); 844 TIMESPEC_TO_TIMEVAL(&tv, &ts1); 845 if (tv.tv_sec < 0) { 846 error = ETIMEDOUT; 847 break; 848 } 849 error = cv_timedwait_sig(&ks->ks_cv, 850 &sem_lock, tvtohz(&tv)); 851 if (error != EWOULDBLOCK) 852 break; 853 } 854 } 855 ks->ks_waiters--; 856 if (error) 857 goto err; 858 } 859 ks->ks_value--; 860 DP(("kern_sem_wait value post-decrement = %d\n", ks->ks_value)); 861 error = 0; 862 err: 863 mtx_unlock(&sem_lock); 864 fdrop(fp, td); 865 DP(("<<< kern_sem_wait leaving, pid=%d, error = %d\n", 866 (int)td->td_proc->p_pid, error)); 867 return (error); 868 } 869 870 #ifndef _SYS_SYSPROTO_H_ 871 struct ksem_getvalue_args { 872 semid_t id; 873 int *val; 874 }; 875 #endif 876 int 877 sys_ksem_getvalue(struct thread *td, struct ksem_getvalue_args *uap) 878 { 879 struct file *fp; 880 struct ksem *ks; 881 int error, val; 882 883 error = ksem_get(td, uap->id, CAP_SEM_GETVALUE, &fp); 884 if (error) 885 return (error); 886 ks = fp->f_data; 887 888 mtx_lock(&sem_lock); 889 #ifdef MAC 890 error = mac_posixsem_check_getvalue(td->td_ucred, fp->f_cred, ks); 891 if (error) { 892 mtx_unlock(&sem_lock); 893 fdrop(fp, td); 894 return (error); 895 } 896 #endif 897 val = ks->ks_value; 898 vfs_timestamp(&ks->ks_atime); 899 mtx_unlock(&sem_lock); 900 fdrop(fp, td); 901 error = copyout(&val, uap->val, sizeof(val)); 902 return (error); 903 } 904 905 #ifndef _SYS_SYSPROTO_H_ 906 struct ksem_destroy_args { 907 semid_t id; 908 }; 909 #endif 910 int 911 sys_ksem_destroy(struct thread *td, struct ksem_destroy_args *uap) 912 { 913 struct file *fp; 914 struct ksem *ks; 915 int error; 916 917 /* No capability rights required to close a semaphore. */ 918 error = ksem_get(td, uap->id, 0, &fp); 919 if (error) 920 return (error); 921 ks = fp->f_data; 922 if (!(ks->ks_flags & KS_ANONYMOUS)) { 923 fdrop(fp, td); 924 return (EINVAL); 925 } 926 mtx_lock(&sem_lock); 927 if (ks->ks_waiters != 0) { 928 mtx_unlock(&sem_lock); 929 error = EBUSY; 930 goto err; 931 } 932 ks->ks_flags |= KS_DEAD; 933 mtx_unlock(&sem_lock); 934 935 error = kern_close(td, uap->id); 936 err: 937 fdrop(fp, td); 938 return (error); 939 } 940 941 static struct syscall_helper_data ksem_syscalls[] = { 942 SYSCALL_INIT_HELPER(ksem_init), 943 SYSCALL_INIT_HELPER(ksem_open), 944 SYSCALL_INIT_HELPER(ksem_unlink), 945 SYSCALL_INIT_HELPER(ksem_close), 946 SYSCALL_INIT_HELPER(ksem_post), 947 SYSCALL_INIT_HELPER(ksem_wait), 948 SYSCALL_INIT_HELPER(ksem_timedwait), 949 SYSCALL_INIT_HELPER(ksem_trywait), 950 SYSCALL_INIT_HELPER(ksem_getvalue), 951 SYSCALL_INIT_HELPER(ksem_destroy), 952 SYSCALL_INIT_LAST 953 }; 954 955 #ifdef COMPAT_FREEBSD32 956 #include <compat/freebsd32/freebsd32.h> 957 #include <compat/freebsd32/freebsd32_proto.h> 958 #include <compat/freebsd32/freebsd32_signal.h> 959 #include <compat/freebsd32/freebsd32_syscall.h> 960 #include <compat/freebsd32/freebsd32_util.h> 961 962 int 963 freebsd32_ksem_init(struct thread *td, struct freebsd32_ksem_init_args *uap) 964 { 965 966 return (ksem_create(td, NULL, uap->idp, S_IRWXU | S_IRWXG, uap->value, 967 0, 1)); 968 } 969 970 int 971 freebsd32_ksem_open(struct thread *td, struct freebsd32_ksem_open_args *uap) 972 { 973 974 if ((uap->oflag & ~(O_CREAT | O_EXCL)) != 0) 975 return (EINVAL); 976 return (ksem_create(td, uap->name, uap->idp, uap->mode, uap->value, 977 uap->oflag, 1)); 978 } 979 980 int 981 freebsd32_ksem_timedwait(struct thread *td, 982 struct freebsd32_ksem_timedwait_args *uap) 983 { 984 struct timespec32 abstime32; 985 struct timespec *ts, abstime; 986 int error; 987 988 /* 989 * We allow a null timespec (wait forever). 990 */ 991 if (uap->abstime == NULL) 992 ts = NULL; 993 else { 994 error = copyin(uap->abstime, &abstime32, sizeof(abstime32)); 995 if (error != 0) 996 return (error); 997 CP(abstime32, abstime, tv_sec); 998 CP(abstime32, abstime, tv_nsec); 999 if (abstime.tv_nsec >= 1000000000 || abstime.tv_nsec < 0) 1000 return (EINVAL); 1001 ts = &abstime; 1002 } 1003 return (kern_sem_wait(td, uap->id, 0, ts)); 1004 } 1005 1006 static struct syscall_helper_data ksem32_syscalls[] = { 1007 SYSCALL32_INIT_HELPER(freebsd32_ksem_init), 1008 SYSCALL32_INIT_HELPER(freebsd32_ksem_open), 1009 SYSCALL32_INIT_HELPER_COMPAT(ksem_unlink), 1010 SYSCALL32_INIT_HELPER_COMPAT(ksem_close), 1011 SYSCALL32_INIT_HELPER_COMPAT(ksem_post), 1012 SYSCALL32_INIT_HELPER_COMPAT(ksem_wait), 1013 SYSCALL32_INIT_HELPER(freebsd32_ksem_timedwait), 1014 SYSCALL32_INIT_HELPER_COMPAT(ksem_trywait), 1015 SYSCALL32_INIT_HELPER_COMPAT(ksem_getvalue), 1016 SYSCALL32_INIT_HELPER_COMPAT(ksem_destroy), 1017 SYSCALL_INIT_LAST 1018 }; 1019 #endif 1020 1021 static int 1022 ksem_module_init(void) 1023 { 1024 int error; 1025 1026 mtx_init(&sem_lock, "sem", NULL, MTX_DEF); 1027 mtx_init(&ksem_count_lock, "ksem count", NULL, MTX_DEF); 1028 sx_init(&ksem_dict_lock, "ksem dictionary"); 1029 ksem_dictionary = hashinit(1024, M_KSEM, &ksem_hash); 1030 p31b_setcfg(CTL_P1003_1B_SEMAPHORES, 200112L); 1031 p31b_setcfg(CTL_P1003_1B_SEM_NSEMS_MAX, SEM_MAX); 1032 p31b_setcfg(CTL_P1003_1B_SEM_VALUE_MAX, SEM_VALUE_MAX); 1033 ksem_info = ksem_info_impl; 1034 1035 error = syscall_helper_register(ksem_syscalls); 1036 if (error) 1037 return (error); 1038 #ifdef COMPAT_FREEBSD32 1039 error = syscall32_helper_register(ksem32_syscalls); 1040 if (error) 1041 return (error); 1042 #endif 1043 return (0); 1044 } 1045 1046 static void 1047 ksem_module_destroy(void) 1048 { 1049 1050 #ifdef COMPAT_FREEBSD32 1051 syscall32_helper_unregister(ksem32_syscalls); 1052 #endif 1053 syscall_helper_unregister(ksem_syscalls); 1054 1055 ksem_info = NULL; 1056 p31b_setcfg(CTL_P1003_1B_SEMAPHORES, 0); 1057 hashdestroy(ksem_dictionary, M_KSEM, ksem_hash); 1058 sx_destroy(&ksem_dict_lock); 1059 mtx_destroy(&ksem_count_lock); 1060 mtx_destroy(&sem_lock); 1061 p31b_unsetcfg(CTL_P1003_1B_SEM_VALUE_MAX); 1062 p31b_unsetcfg(CTL_P1003_1B_SEM_NSEMS_MAX); 1063 } 1064 1065 static int 1066 sem_modload(struct module *module, int cmd, void *arg) 1067 { 1068 int error = 0; 1069 1070 switch (cmd) { 1071 case MOD_LOAD: 1072 error = ksem_module_init(); 1073 if (error) 1074 ksem_module_destroy(); 1075 break; 1076 1077 case MOD_UNLOAD: 1078 mtx_lock(&ksem_count_lock); 1079 if (nsems != 0) { 1080 error = EOPNOTSUPP; 1081 mtx_unlock(&ksem_count_lock); 1082 break; 1083 } 1084 ksem_dead = 1; 1085 mtx_unlock(&ksem_count_lock); 1086 ksem_module_destroy(); 1087 break; 1088 1089 case MOD_SHUTDOWN: 1090 break; 1091 default: 1092 error = EINVAL; 1093 break; 1094 } 1095 return (error); 1096 } 1097 1098 static moduledata_t sem_mod = { 1099 "sem", 1100 &sem_modload, 1101 NULL 1102 }; 1103 1104 DECLARE_MODULE(sem, sem_mod, SI_SUB_SYSV_SEM, SI_ORDER_FIRST); 1105 MODULE_VERSION(sem, 1); 1106