1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause 3 * 4 * Copyright (c) 2002 Alfred Perlstein <alfred@FreeBSD.org> 5 * Copyright (c) 2003-2005 SPARTA, Inc. 6 * Copyright (c) 2005, 2016-2017 Robert N. M. Watson 7 * All rights reserved. 8 * 9 * This software was developed for the FreeBSD Project in part by Network 10 * Associates Laboratories, the Security Research Division of Network 11 * Associates, Inc. under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), 12 * as part of the DARPA CHATS research program. 13 * 14 * Portions of this software were developed by BAE Systems, the University of 15 * Cambridge Computer Laboratory, and Memorial University under DARPA/AFRL 16 * contract FA8650-15-C-7558 ("CADETS"), as part of the DARPA Transparent 17 * Computing (TC) research program. 18 * 19 * Redistribution and use in source and binary forms, with or without 20 * modification, are permitted provided that the following conditions 21 * are met: 22 * 1. Redistributions of source code must retain the above copyright 23 * notice, this list of conditions and the following disclaimer. 24 * 2. Redistributions in binary form must reproduce the above copyright 25 * notice, this list of conditions and the following disclaimer in the 26 * documentation and/or other materials provided with the distribution. 27 * 28 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 29 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 30 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 31 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 32 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 33 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 34 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 35 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 36 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 37 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 38 * SUCH DAMAGE. 39 */ 40 41 #include <sys/cdefs.h> 42 #include "opt_posix.h" 43 44 #include <sys/param.h> 45 #include <sys/capsicum.h> 46 #include <sys/condvar.h> 47 #include <sys/fcntl.h> 48 #include <sys/file.h> 49 #include <sys/filedesc.h> 50 #include <sys/fnv_hash.h> 51 #include <sys/jail.h> 52 #include <sys/kernel.h> 53 #include <sys/ksem.h> 54 #include <sys/lock.h> 55 #include <sys/malloc.h> 56 #include <sys/module.h> 57 #include <sys/mutex.h> 58 #include <sys/priv.h> 59 #include <sys/proc.h> 60 #include <sys/posix4.h> 61 #include <sys/_semaphore.h> 62 #include <sys/stat.h> 63 #include <sys/syscall.h> 64 #include <sys/syscallsubr.h> 65 #include <sys/sysctl.h> 66 #include <sys/sysent.h> 67 #include <sys/sysproto.h> 68 #include <sys/systm.h> 69 #include <sys/sx.h> 70 #include <sys/user.h> 71 #include <sys/vnode.h> 72 73 #include <security/audit/audit.h> 74 #include <security/mac/mac_framework.h> 75 76 FEATURE(p1003_1b_semaphores, "POSIX P1003.1B semaphores support"); 77 /* 78 * TODO 79 * 80 * - Resource limits? 81 * - Replace global sem_lock with mtx_pool locks? 82 * - Add a MAC check_create() hook for creating new named semaphores. 83 */ 84 85 #ifndef SEM_MAX 86 #define SEM_MAX 30 87 #endif 88 89 #ifdef SEM_DEBUG 90 #define DP(x) printf x 91 #else 92 #define DP(x) 93 #endif 94 95 struct ksem_mapping { 96 char *km_path; 97 Fnv32_t km_fnv; 98 struct ksem *km_ksem; 99 LIST_ENTRY(ksem_mapping) km_link; 100 }; 101 102 static MALLOC_DEFINE(M_KSEM, "ksem", "semaphore file descriptor"); 103 static LIST_HEAD(, ksem_mapping) *ksem_dictionary; 104 static struct sx ksem_dict_lock; 105 static struct mtx ksem_count_lock; 106 static struct mtx sem_lock; 107 static u_long ksem_hash; 108 static int ksem_dead; 109 110 #define KSEM_HASH(fnv) (&ksem_dictionary[(fnv) & ksem_hash]) 111 112 static int nsems = 0; 113 SYSCTL_DECL(_p1003_1b); 114 SYSCTL_INT(_p1003_1b, OID_AUTO, nsems, CTLFLAG_RD, &nsems, 0, 115 "Number of active kernel POSIX semaphores"); 116 117 static int kern_sem_wait(struct thread *td, semid_t id, int tryflag, 118 struct timespec *abstime); 119 static int ksem_access(struct ksem *ks, struct ucred *ucred); 120 static struct ksem *ksem_alloc(struct ucred *ucred, mode_t mode, 121 unsigned int value); 122 static int ksem_create(struct thread *td, const char *path, 123 semid_t *semidp, mode_t mode, unsigned int value, 124 int flags, int compat32); 125 static void ksem_drop(struct ksem *ks); 126 static int ksem_get(struct thread *td, semid_t id, cap_rights_t *rightsp, 127 struct file **fpp); 128 static struct ksem *ksem_hold(struct ksem *ks); 129 static void ksem_insert(char *path, Fnv32_t fnv, struct ksem *ks); 130 static struct ksem *ksem_lookup(char *path, Fnv32_t fnv); 131 static void ksem_module_destroy(void); 132 static int ksem_module_init(void); 133 static int ksem_remove(char *path, Fnv32_t fnv, struct ucred *ucred); 134 static int sem_modload(struct module *module, int cmd, void *arg); 135 136 static fo_stat_t ksem_stat; 137 static fo_close_t ksem_closef; 138 static fo_chmod_t ksem_chmod; 139 static fo_chown_t ksem_chown; 140 static fo_fill_kinfo_t ksem_fill_kinfo; 141 142 /* File descriptor operations. */ 143 static struct fileops ksem_ops = { 144 .fo_read = invfo_rdwr, 145 .fo_write = invfo_rdwr, 146 .fo_truncate = invfo_truncate, 147 .fo_ioctl = invfo_ioctl, 148 .fo_poll = invfo_poll, 149 .fo_kqfilter = invfo_kqfilter, 150 .fo_stat = ksem_stat, 151 .fo_close = ksem_closef, 152 .fo_chmod = ksem_chmod, 153 .fo_chown = ksem_chown, 154 .fo_sendfile = invfo_sendfile, 155 .fo_fill_kinfo = ksem_fill_kinfo, 156 .fo_cmp = file_kcmp_generic, 157 .fo_flags = DFLAG_PASSABLE 158 }; 159 160 FEATURE(posix_sem, "POSIX semaphores"); 161 162 static int 163 ksem_stat(struct file *fp, struct stat *sb, struct ucred *active_cred) 164 { 165 struct ksem *ks; 166 #ifdef MAC 167 int error; 168 #endif 169 170 ks = fp->f_data; 171 172 #ifdef MAC 173 error = mac_posixsem_check_stat(active_cred, fp->f_cred, ks); 174 if (error) 175 return (error); 176 #endif 177 178 /* 179 * Attempt to return sanish values for fstat() on a semaphore 180 * file descriptor. 181 */ 182 bzero(sb, sizeof(*sb)); 183 184 mtx_lock(&sem_lock); 185 sb->st_atim = ks->ks_atime; 186 sb->st_ctim = ks->ks_ctime; 187 sb->st_mtim = ks->ks_mtime; 188 sb->st_birthtim = ks->ks_birthtime; 189 sb->st_uid = ks->ks_uid; 190 sb->st_gid = ks->ks_gid; 191 sb->st_mode = S_IFREG | ks->ks_mode; /* XXX */ 192 mtx_unlock(&sem_lock); 193 194 return (0); 195 } 196 197 static int 198 ksem_chmod(struct file *fp, mode_t mode, struct ucred *active_cred, 199 struct thread *td) 200 { 201 struct ksem *ks; 202 int error; 203 204 error = 0; 205 ks = fp->f_data; 206 mtx_lock(&sem_lock); 207 #ifdef MAC 208 error = mac_posixsem_check_setmode(active_cred, ks, mode); 209 if (error != 0) 210 goto out; 211 #endif 212 error = vaccess(VREG, ks->ks_mode, ks->ks_uid, ks->ks_gid, VADMIN, 213 active_cred); 214 if (error != 0) 215 goto out; 216 ks->ks_mode = mode & ACCESSPERMS; 217 out: 218 mtx_unlock(&sem_lock); 219 return (error); 220 } 221 222 static int 223 ksem_chown(struct file *fp, uid_t uid, gid_t gid, struct ucred *active_cred, 224 struct thread *td) 225 { 226 struct ksem *ks; 227 int error; 228 229 error = 0; 230 ks = fp->f_data; 231 mtx_lock(&sem_lock); 232 #ifdef MAC 233 error = mac_posixsem_check_setowner(active_cred, ks, uid, gid); 234 if (error != 0) 235 goto out; 236 #endif 237 if (uid == (uid_t)-1) 238 uid = ks->ks_uid; 239 if (gid == (gid_t)-1) 240 gid = ks->ks_gid; 241 if (((uid != ks->ks_uid && uid != active_cred->cr_uid) || 242 (gid != ks->ks_gid && !groupmember(gid, active_cred))) && 243 (error = priv_check_cred(active_cred, PRIV_VFS_CHOWN))) 244 goto out; 245 ks->ks_uid = uid; 246 ks->ks_gid = gid; 247 out: 248 mtx_unlock(&sem_lock); 249 return (error); 250 } 251 252 static int 253 ksem_closef(struct file *fp, struct thread *td) 254 { 255 struct ksem *ks; 256 257 ks = fp->f_data; 258 fp->f_data = NULL; 259 ksem_drop(ks); 260 261 return (0); 262 } 263 264 static int 265 ksem_fill_kinfo(struct file *fp, struct kinfo_file *kif, struct filedesc *fdp) 266 { 267 const char *path, *pr_path; 268 struct ksem *ks; 269 size_t pr_pathlen; 270 271 kif->kf_type = KF_TYPE_SEM; 272 ks = fp->f_data; 273 mtx_lock(&sem_lock); 274 kif->kf_un.kf_sem.kf_sem_value = ks->ks_value; 275 kif->kf_un.kf_sem.kf_sem_mode = S_IFREG | ks->ks_mode; /* XXX */ 276 mtx_unlock(&sem_lock); 277 if (ks->ks_path != NULL) { 278 sx_slock(&ksem_dict_lock); 279 if (ks->ks_path != NULL) { 280 path = ks->ks_path; 281 pr_path = curthread->td_ucred->cr_prison->pr_path; 282 if (strcmp(pr_path, "/") != 0) { 283 /* Return the jail-rooted pathname. */ 284 pr_pathlen = strlen(pr_path); 285 if (strncmp(path, pr_path, pr_pathlen) == 0 && 286 path[pr_pathlen] == '/') 287 path += pr_pathlen; 288 } 289 strlcpy(kif->kf_path, path, sizeof(kif->kf_path)); 290 } 291 sx_sunlock(&ksem_dict_lock); 292 } 293 return (0); 294 } 295 296 /* 297 * ksem object management including creation and reference counting 298 * routines. 299 */ 300 static struct ksem * 301 ksem_alloc(struct ucred *ucred, mode_t mode, unsigned int value) 302 { 303 struct ksem *ks; 304 305 mtx_lock(&ksem_count_lock); 306 if (nsems == p31b_getcfg(CTL_P1003_1B_SEM_NSEMS_MAX) || ksem_dead) { 307 mtx_unlock(&ksem_count_lock); 308 return (NULL); 309 } 310 nsems++; 311 mtx_unlock(&ksem_count_lock); 312 ks = malloc(sizeof(*ks), M_KSEM, M_WAITOK | M_ZERO); 313 ks->ks_uid = ucred->cr_uid; 314 ks->ks_gid = ucred->cr_gid; 315 ks->ks_mode = mode; 316 ks->ks_value = value; 317 cv_init(&ks->ks_cv, "ksem"); 318 vfs_timestamp(&ks->ks_birthtime); 319 ks->ks_atime = ks->ks_mtime = ks->ks_ctime = ks->ks_birthtime; 320 refcount_init(&ks->ks_ref, 1); 321 #ifdef MAC 322 mac_posixsem_init(ks); 323 mac_posixsem_create(ucred, ks); 324 #endif 325 326 return (ks); 327 } 328 329 static struct ksem * 330 ksem_hold(struct ksem *ks) 331 { 332 333 refcount_acquire(&ks->ks_ref); 334 return (ks); 335 } 336 337 static void 338 ksem_drop(struct ksem *ks) 339 { 340 341 if (refcount_release(&ks->ks_ref)) { 342 #ifdef MAC 343 mac_posixsem_destroy(ks); 344 #endif 345 cv_destroy(&ks->ks_cv); 346 free(ks, M_KSEM); 347 mtx_lock(&ksem_count_lock); 348 nsems--; 349 mtx_unlock(&ksem_count_lock); 350 } 351 } 352 353 /* 354 * Determine if the credentials have sufficient permissions for read 355 * and write access. 356 */ 357 static int 358 ksem_access(struct ksem *ks, struct ucred *ucred) 359 { 360 int error; 361 362 error = vaccess(VREG, ks->ks_mode, ks->ks_uid, ks->ks_gid, 363 VREAD | VWRITE, ucred); 364 if (error) 365 error = priv_check_cred(ucred, PRIV_SEM_WRITE); 366 return (error); 367 } 368 369 /* 370 * Dictionary management. We maintain an in-kernel dictionary to map 371 * paths to semaphore objects. We use the FNV hash on the path to 372 * store the mappings in a hash table. 373 */ 374 static struct ksem * 375 ksem_lookup(char *path, Fnv32_t fnv) 376 { 377 struct ksem_mapping *map; 378 379 LIST_FOREACH(map, KSEM_HASH(fnv), km_link) { 380 if (map->km_fnv != fnv) 381 continue; 382 if (strcmp(map->km_path, path) == 0) 383 return (map->km_ksem); 384 } 385 386 return (NULL); 387 } 388 389 static void 390 ksem_insert(char *path, Fnv32_t fnv, struct ksem *ks) 391 { 392 struct ksem_mapping *map; 393 394 map = malloc(sizeof(struct ksem_mapping), M_KSEM, M_WAITOK); 395 map->km_path = path; 396 map->km_fnv = fnv; 397 map->km_ksem = ksem_hold(ks); 398 ks->ks_path = path; 399 LIST_INSERT_HEAD(KSEM_HASH(fnv), map, km_link); 400 } 401 402 static int 403 ksem_remove(char *path, Fnv32_t fnv, struct ucred *ucred) 404 { 405 struct ksem_mapping *map; 406 int error; 407 408 LIST_FOREACH(map, KSEM_HASH(fnv), km_link) { 409 if (map->km_fnv != fnv) 410 continue; 411 if (strcmp(map->km_path, path) == 0) { 412 #ifdef MAC 413 error = mac_posixsem_check_unlink(ucred, map->km_ksem); 414 if (error) 415 return (error); 416 #endif 417 error = ksem_access(map->km_ksem, ucred); 418 if (error) 419 return (error); 420 map->km_ksem->ks_path = NULL; 421 LIST_REMOVE(map, km_link); 422 ksem_drop(map->km_ksem); 423 free(map->km_path, M_KSEM); 424 free(map, M_KSEM); 425 return (0); 426 } 427 } 428 429 return (ENOENT); 430 } 431 432 static int 433 ksem_create_copyout_semid(struct thread *td, semid_t *semidp, int fd, 434 int compat32) 435 { 436 semid_t semid; 437 #ifdef COMPAT_FREEBSD32 438 int32_t semid32; 439 #endif 440 void *ptr; 441 size_t ptrs; 442 443 #ifdef COMPAT_FREEBSD32 444 if (compat32) { 445 semid32 = fd; 446 ptr = &semid32; 447 ptrs = sizeof(semid32); 448 } else { 449 #endif 450 semid = fd; 451 ptr = &semid; 452 ptrs = sizeof(semid); 453 compat32 = 0; /* silence gcc */ 454 #ifdef COMPAT_FREEBSD32 455 } 456 #endif 457 458 return (copyout(ptr, semidp, ptrs)); 459 } 460 461 /* Other helper routines. */ 462 static int 463 ksem_create(struct thread *td, const char *name, semid_t *semidp, mode_t mode, 464 unsigned int value, int flags, int compat32) 465 { 466 struct pwddesc *pdp; 467 struct ksem *ks; 468 struct file *fp; 469 char *path; 470 const char *pr_path; 471 size_t pr_pathlen; 472 Fnv32_t fnv; 473 int error, fd; 474 475 AUDIT_ARG_FFLAGS(flags); 476 AUDIT_ARG_MODE(mode); 477 AUDIT_ARG_VALUE(value); 478 479 if (value > SEM_VALUE_MAX) 480 return (EINVAL); 481 482 pdp = td->td_proc->p_pd; 483 mode = (mode & ~pdp->pd_cmask) & ACCESSPERMS; 484 error = falloc(td, &fp, &fd, O_CLOEXEC); 485 if (error) { 486 if (name == NULL) 487 error = ENOSPC; 488 return (error); 489 } 490 491 /* 492 * Go ahead and copyout the file descriptor now. This is a bit 493 * premature, but it is a lot easier to handle errors as opposed 494 * to later when we've possibly created a new semaphore, etc. 495 */ 496 error = ksem_create_copyout_semid(td, semidp, fd, compat32); 497 if (error) { 498 fdclose(td, fp, fd); 499 fdrop(fp, td); 500 return (error); 501 } 502 503 if (name == NULL) { 504 /* Create an anonymous semaphore. */ 505 ks = ksem_alloc(td->td_ucred, mode, value); 506 if (ks == NULL) 507 error = ENOSPC; 508 else 509 ks->ks_flags |= KS_ANONYMOUS; 510 } else { 511 path = malloc(MAXPATHLEN, M_KSEM, M_WAITOK); 512 pr_path = td->td_ucred->cr_prison->pr_path; 513 514 /* Construct a full pathname for jailed callers. */ 515 pr_pathlen = strcmp(pr_path, "/") == 0 ? 0 516 : strlcpy(path, pr_path, MAXPATHLEN); 517 error = copyinstr(name, path + pr_pathlen, 518 MAXPATHLEN - pr_pathlen, NULL); 519 520 /* Require paths to start with a '/' character. */ 521 if (error == 0 && path[pr_pathlen] != '/') 522 error = EINVAL; 523 if (error) { 524 fdclose(td, fp, fd); 525 fdrop(fp, td); 526 free(path, M_KSEM); 527 return (error); 528 } 529 530 AUDIT_ARG_UPATH1_CANON(path); 531 fnv = fnv_32_str(path, FNV1_32_INIT); 532 sx_xlock(&ksem_dict_lock); 533 ks = ksem_lookup(path, fnv); 534 if (ks == NULL) { 535 /* Object does not exist, create it if requested. */ 536 if (flags & O_CREAT) { 537 ks = ksem_alloc(td->td_ucred, mode, value); 538 if (ks == NULL) 539 error = ENFILE; 540 else { 541 ksem_insert(path, fnv, ks); 542 path = NULL; 543 } 544 } else 545 error = ENOENT; 546 } else { 547 /* 548 * Object already exists, obtain a new 549 * reference if requested and permitted. 550 */ 551 if ((flags & (O_CREAT | O_EXCL)) == 552 (O_CREAT | O_EXCL)) 553 error = EEXIST; 554 else { 555 #ifdef MAC 556 error = mac_posixsem_check_open(td->td_ucred, 557 ks); 558 if (error == 0) 559 #endif 560 error = ksem_access(ks, td->td_ucred); 561 } 562 if (error == 0) 563 ksem_hold(ks); 564 #ifdef INVARIANTS 565 else 566 ks = NULL; 567 #endif 568 } 569 sx_xunlock(&ksem_dict_lock); 570 if (path) 571 free(path, M_KSEM); 572 } 573 574 if (error) { 575 KASSERT(ks == NULL, ("ksem_create error with a ksem")); 576 fdclose(td, fp, fd); 577 fdrop(fp, td); 578 return (error); 579 } 580 KASSERT(ks != NULL, ("ksem_create w/o a ksem")); 581 582 finit(fp, FREAD | FWRITE, DTYPE_SEM, ks, &ksem_ops); 583 584 fdrop(fp, td); 585 586 return (0); 587 } 588 589 static int 590 ksem_get(struct thread *td, semid_t id, cap_rights_t *rightsp, 591 struct file **fpp) 592 { 593 struct ksem *ks; 594 struct file *fp; 595 int error; 596 597 error = fget(td, id, rightsp, &fp); 598 if (error) 599 return (EINVAL); 600 if (fp->f_type != DTYPE_SEM) { 601 fdrop(fp, td); 602 return (EINVAL); 603 } 604 ks = fp->f_data; 605 if (ks->ks_flags & KS_DEAD) { 606 fdrop(fp, td); 607 return (EINVAL); 608 } 609 *fpp = fp; 610 return (0); 611 } 612 613 /* System calls. */ 614 #ifndef _SYS_SYSPROTO_H_ 615 struct ksem_init_args { 616 unsigned int value; 617 semid_t *idp; 618 }; 619 #endif 620 int 621 sys_ksem_init(struct thread *td, struct ksem_init_args *uap) 622 { 623 624 return (ksem_create(td, NULL, uap->idp, S_IRWXU | S_IRWXG, uap->value, 625 0, 0)); 626 } 627 628 #ifndef _SYS_SYSPROTO_H_ 629 struct ksem_open_args { 630 char *name; 631 int oflag; 632 mode_t mode; 633 unsigned int value; 634 semid_t *idp; 635 }; 636 #endif 637 int 638 sys_ksem_open(struct thread *td, struct ksem_open_args *uap) 639 { 640 641 DP((">>> ksem_open start, pid=%d\n", (int)td->td_proc->p_pid)); 642 643 if ((uap->oflag & ~(O_CREAT | O_EXCL)) != 0) 644 return (EINVAL); 645 return (ksem_create(td, uap->name, uap->idp, uap->mode, uap->value, 646 uap->oflag, 0)); 647 } 648 649 #ifndef _SYS_SYSPROTO_H_ 650 struct ksem_unlink_args { 651 char *name; 652 }; 653 #endif 654 int 655 sys_ksem_unlink(struct thread *td, struct ksem_unlink_args *uap) 656 { 657 char *path; 658 const char *pr_path; 659 size_t pr_pathlen; 660 Fnv32_t fnv; 661 int error; 662 663 path = malloc(MAXPATHLEN, M_TEMP, M_WAITOK); 664 pr_path = td->td_ucred->cr_prison->pr_path; 665 pr_pathlen = strcmp(pr_path, "/") == 0 ? 0 666 : strlcpy(path, pr_path, MAXPATHLEN); 667 error = copyinstr(uap->name, path + pr_pathlen, MAXPATHLEN - pr_pathlen, 668 NULL); 669 if (error) { 670 free(path, M_TEMP); 671 return (error); 672 } 673 674 AUDIT_ARG_UPATH1_CANON(path); 675 fnv = fnv_32_str(path, FNV1_32_INIT); 676 sx_xlock(&ksem_dict_lock); 677 error = ksem_remove(path, fnv, td->td_ucred); 678 sx_xunlock(&ksem_dict_lock); 679 free(path, M_TEMP); 680 681 return (error); 682 } 683 684 #ifndef _SYS_SYSPROTO_H_ 685 struct ksem_close_args { 686 semid_t id; 687 }; 688 #endif 689 int 690 sys_ksem_close(struct thread *td, struct ksem_close_args *uap) 691 { 692 struct ksem *ks; 693 struct file *fp; 694 int error; 695 696 /* No capability rights required to close a semaphore. */ 697 AUDIT_ARG_FD(uap->id); 698 error = ksem_get(td, uap->id, &cap_no_rights, &fp); 699 if (error) 700 return (error); 701 ks = fp->f_data; 702 if (ks->ks_flags & KS_ANONYMOUS) { 703 fdrop(fp, td); 704 return (EINVAL); 705 } 706 error = kern_close(td, uap->id); 707 fdrop(fp, td); 708 return (error); 709 } 710 711 #ifndef _SYS_SYSPROTO_H_ 712 struct ksem_post_args { 713 semid_t id; 714 }; 715 #endif 716 int 717 sys_ksem_post(struct thread *td, struct ksem_post_args *uap) 718 { 719 cap_rights_t rights; 720 struct file *fp; 721 struct ksem *ks; 722 int error; 723 724 AUDIT_ARG_FD(uap->id); 725 error = ksem_get(td, uap->id, 726 cap_rights_init_one(&rights, CAP_SEM_POST), &fp); 727 if (error) 728 return (error); 729 ks = fp->f_data; 730 731 mtx_lock(&sem_lock); 732 #ifdef MAC 733 error = mac_posixsem_check_post(td->td_ucred, fp->f_cred, ks); 734 if (error) 735 goto err; 736 #endif 737 if (ks->ks_value == SEM_VALUE_MAX) { 738 error = EOVERFLOW; 739 goto err; 740 } 741 ++ks->ks_value; 742 if (ks->ks_waiters > 0) 743 cv_signal(&ks->ks_cv); 744 error = 0; 745 vfs_timestamp(&ks->ks_ctime); 746 err: 747 mtx_unlock(&sem_lock); 748 fdrop(fp, td); 749 return (error); 750 } 751 752 #ifndef _SYS_SYSPROTO_H_ 753 struct ksem_wait_args { 754 semid_t id; 755 }; 756 #endif 757 int 758 sys_ksem_wait(struct thread *td, struct ksem_wait_args *uap) 759 { 760 761 return (kern_sem_wait(td, uap->id, 0, NULL)); 762 } 763 764 #ifndef _SYS_SYSPROTO_H_ 765 struct ksem_timedwait_args { 766 semid_t id; 767 const struct timespec *abstime; 768 }; 769 #endif 770 int 771 sys_ksem_timedwait(struct thread *td, struct ksem_timedwait_args *uap) 772 { 773 struct timespec abstime; 774 struct timespec *ts; 775 int error; 776 777 /* 778 * We allow a null timespec (wait forever). 779 */ 780 if (uap->abstime == NULL) 781 ts = NULL; 782 else { 783 error = copyin(uap->abstime, &abstime, sizeof(abstime)); 784 if (error != 0) 785 return (error); 786 if (abstime.tv_nsec >= 1000000000 || abstime.tv_nsec < 0) 787 return (EINVAL); 788 ts = &abstime; 789 } 790 return (kern_sem_wait(td, uap->id, 0, ts)); 791 } 792 793 #ifndef _SYS_SYSPROTO_H_ 794 struct ksem_trywait_args { 795 semid_t id; 796 }; 797 #endif 798 int 799 sys_ksem_trywait(struct thread *td, struct ksem_trywait_args *uap) 800 { 801 802 return (kern_sem_wait(td, uap->id, 1, NULL)); 803 } 804 805 static int 806 kern_sem_wait(struct thread *td, semid_t id, int tryflag, 807 struct timespec *abstime) 808 { 809 struct timespec ts1, ts2; 810 struct timeval tv; 811 cap_rights_t rights; 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 AUDIT_ARG_FD(id); 818 error = ksem_get(td, id, cap_rights_init_one(&rights, CAP_SEM_WAIT), 819 &fp); 820 if (error) 821 return (error); 822 ks = fp->f_data; 823 mtx_lock(&sem_lock); 824 DP((">>> kern_sem_wait critical section entered! pid=%d\n", 825 (int)td->td_proc->p_pid)); 826 #ifdef MAC 827 error = mac_posixsem_check_wait(td->td_ucred, fp->f_cred, ks); 828 if (error) { 829 DP(("kern_sem_wait mac failed\n")); 830 goto err; 831 } 832 #endif 833 DP(("kern_sem_wait value = %d, tryflag %d\n", ks->ks_value, tryflag)); 834 vfs_timestamp(&ks->ks_atime); 835 while (ks->ks_value == 0) { 836 ks->ks_waiters++; 837 if (tryflag != 0) 838 error = EAGAIN; 839 else if (abstime == NULL) 840 error = cv_wait_sig(&ks->ks_cv, &sem_lock); 841 else { 842 for (;;) { 843 ts1 = *abstime; 844 getnanotime(&ts2); 845 timespecsub(&ts1, &ts2, &ts1); 846 TIMESPEC_TO_TIMEVAL(&tv, &ts1); 847 if (tv.tv_sec < 0) { 848 error = ETIMEDOUT; 849 break; 850 } 851 error = cv_timedwait_sig(&ks->ks_cv, 852 &sem_lock, tvtohz(&tv)); 853 if (error != EWOULDBLOCK) 854 break; 855 } 856 } 857 ks->ks_waiters--; 858 if (error) 859 goto err; 860 } 861 ks->ks_value--; 862 DP(("kern_sem_wait value post-decrement = %d\n", ks->ks_value)); 863 error = 0; 864 err: 865 mtx_unlock(&sem_lock); 866 fdrop(fp, td); 867 DP(("<<< kern_sem_wait leaving, pid=%d, error = %d\n", 868 (int)td->td_proc->p_pid, error)); 869 return (error); 870 } 871 872 #ifndef _SYS_SYSPROTO_H_ 873 struct ksem_getvalue_args { 874 semid_t id; 875 int *val; 876 }; 877 #endif 878 int 879 sys_ksem_getvalue(struct thread *td, struct ksem_getvalue_args *uap) 880 { 881 cap_rights_t rights; 882 struct file *fp; 883 struct ksem *ks; 884 int error, val; 885 886 AUDIT_ARG_FD(uap->id); 887 error = ksem_get(td, uap->id, 888 cap_rights_init_one(&rights, CAP_SEM_GETVALUE), &fp); 889 if (error) 890 return (error); 891 ks = fp->f_data; 892 893 mtx_lock(&sem_lock); 894 #ifdef MAC 895 error = mac_posixsem_check_getvalue(td->td_ucred, fp->f_cred, ks); 896 if (error) { 897 mtx_unlock(&sem_lock); 898 fdrop(fp, td); 899 return (error); 900 } 901 #endif 902 val = ks->ks_value; 903 vfs_timestamp(&ks->ks_atime); 904 mtx_unlock(&sem_lock); 905 fdrop(fp, td); 906 error = copyout(&val, uap->val, sizeof(val)); 907 return (error); 908 } 909 910 #ifndef _SYS_SYSPROTO_H_ 911 struct ksem_destroy_args { 912 semid_t id; 913 }; 914 #endif 915 int 916 sys_ksem_destroy(struct thread *td, struct ksem_destroy_args *uap) 917 { 918 struct file *fp; 919 struct ksem *ks; 920 int error; 921 922 /* No capability rights required to close a semaphore. */ 923 AUDIT_ARG_FD(uap->id); 924 error = ksem_get(td, uap->id, &cap_no_rights, &fp); 925 if (error) 926 return (error); 927 ks = fp->f_data; 928 if (!(ks->ks_flags & KS_ANONYMOUS)) { 929 fdrop(fp, td); 930 return (EINVAL); 931 } 932 mtx_lock(&sem_lock); 933 if (ks->ks_waiters != 0) { 934 mtx_unlock(&sem_lock); 935 error = EBUSY; 936 goto err; 937 } 938 ks->ks_flags |= KS_DEAD; 939 mtx_unlock(&sem_lock); 940 941 error = kern_close(td, uap->id); 942 err: 943 fdrop(fp, td); 944 return (error); 945 } 946 947 static struct syscall_helper_data ksem_syscalls[] = { 948 SYSCALL_INIT_HELPER(ksem_init), 949 SYSCALL_INIT_HELPER(ksem_open), 950 SYSCALL_INIT_HELPER(ksem_unlink), 951 SYSCALL_INIT_HELPER(ksem_close), 952 SYSCALL_INIT_HELPER(ksem_post), 953 SYSCALL_INIT_HELPER(ksem_wait), 954 SYSCALL_INIT_HELPER(ksem_timedwait), 955 SYSCALL_INIT_HELPER(ksem_trywait), 956 SYSCALL_INIT_HELPER(ksem_getvalue), 957 SYSCALL_INIT_HELPER(ksem_destroy), 958 SYSCALL_INIT_LAST 959 }; 960 961 #ifdef COMPAT_FREEBSD32 962 #include <compat/freebsd32/freebsd32.h> 963 #include <compat/freebsd32/freebsd32_proto.h> 964 #include <compat/freebsd32/freebsd32_signal.h> 965 #include <compat/freebsd32/freebsd32_syscall.h> 966 #include <compat/freebsd32/freebsd32_util.h> 967 968 int 969 freebsd32_ksem_init(struct thread *td, struct freebsd32_ksem_init_args *uap) 970 { 971 972 return (ksem_create(td, NULL, (semid_t *)uap->idp, S_IRWXU | S_IRWXG, uap->value, 973 0, 1)); 974 } 975 976 int 977 freebsd32_ksem_open(struct thread *td, struct freebsd32_ksem_open_args *uap) 978 { 979 980 if ((uap->oflag & ~(O_CREAT | O_EXCL)) != 0) 981 return (EINVAL); 982 return (ksem_create(td, uap->name, (semid_t *)uap->idp, uap->mode, uap->value, 983 uap->oflag, 1)); 984 } 985 986 int 987 freebsd32_ksem_timedwait(struct thread *td, 988 struct freebsd32_ksem_timedwait_args *uap) 989 { 990 struct timespec32 abstime32; 991 struct timespec *ts, abstime; 992 int error; 993 994 /* 995 * We allow a null timespec (wait forever). 996 */ 997 if (uap->abstime == NULL) 998 ts = NULL; 999 else { 1000 error = copyin(uap->abstime, &abstime32, sizeof(abstime32)); 1001 if (error != 0) 1002 return (error); 1003 CP(abstime32, abstime, tv_sec); 1004 CP(abstime32, abstime, tv_nsec); 1005 if (abstime.tv_nsec >= 1000000000 || abstime.tv_nsec < 0) 1006 return (EINVAL); 1007 ts = &abstime; 1008 } 1009 return (kern_sem_wait(td, uap->id, 0, ts)); 1010 } 1011 1012 static struct syscall_helper_data ksem32_syscalls[] = { 1013 SYSCALL32_INIT_HELPER(freebsd32_ksem_init), 1014 SYSCALL32_INIT_HELPER(freebsd32_ksem_open), 1015 SYSCALL32_INIT_HELPER_COMPAT(ksem_unlink), 1016 SYSCALL32_INIT_HELPER_COMPAT(ksem_close), 1017 SYSCALL32_INIT_HELPER_COMPAT(ksem_post), 1018 SYSCALL32_INIT_HELPER_COMPAT(ksem_wait), 1019 SYSCALL32_INIT_HELPER(freebsd32_ksem_timedwait), 1020 SYSCALL32_INIT_HELPER_COMPAT(ksem_trywait), 1021 SYSCALL32_INIT_HELPER_COMPAT(ksem_getvalue), 1022 SYSCALL32_INIT_HELPER_COMPAT(ksem_destroy), 1023 SYSCALL_INIT_LAST 1024 }; 1025 #endif 1026 1027 static int 1028 ksem_module_init(void) 1029 { 1030 int error; 1031 1032 mtx_init(&sem_lock, "sem", NULL, MTX_DEF); 1033 mtx_init(&ksem_count_lock, "ksem count", NULL, MTX_DEF); 1034 sx_init(&ksem_dict_lock, "ksem dictionary"); 1035 ksem_dictionary = hashinit(1024, M_KSEM, &ksem_hash); 1036 p31b_setcfg(CTL_P1003_1B_SEMAPHORES, 200112L); 1037 p31b_setcfg(CTL_P1003_1B_SEM_NSEMS_MAX, SEM_MAX); 1038 p31b_setcfg(CTL_P1003_1B_SEM_VALUE_MAX, SEM_VALUE_MAX); 1039 1040 error = syscall_helper_register(ksem_syscalls, SY_THR_STATIC_KLD); 1041 if (error) 1042 return (error); 1043 #ifdef COMPAT_FREEBSD32 1044 error = syscall32_helper_register(ksem32_syscalls, SY_THR_STATIC_KLD); 1045 if (error) 1046 return (error); 1047 #endif 1048 return (0); 1049 } 1050 1051 static void 1052 ksem_module_destroy(void) 1053 { 1054 1055 #ifdef COMPAT_FREEBSD32 1056 syscall32_helper_unregister(ksem32_syscalls); 1057 #endif 1058 syscall_helper_unregister(ksem_syscalls); 1059 1060 p31b_setcfg(CTL_P1003_1B_SEMAPHORES, 0); 1061 hashdestroy(ksem_dictionary, M_KSEM, ksem_hash); 1062 sx_destroy(&ksem_dict_lock); 1063 mtx_destroy(&ksem_count_lock); 1064 mtx_destroy(&sem_lock); 1065 p31b_unsetcfg(CTL_P1003_1B_SEM_VALUE_MAX); 1066 p31b_unsetcfg(CTL_P1003_1B_SEM_NSEMS_MAX); 1067 } 1068 1069 static int 1070 sem_modload(struct module *module, int cmd, void *arg) 1071 { 1072 int error = 0; 1073 1074 switch (cmd) { 1075 case MOD_LOAD: 1076 error = ksem_module_init(); 1077 if (error) 1078 ksem_module_destroy(); 1079 break; 1080 1081 case MOD_UNLOAD: 1082 mtx_lock(&ksem_count_lock); 1083 if (nsems != 0) { 1084 error = EOPNOTSUPP; 1085 mtx_unlock(&ksem_count_lock); 1086 break; 1087 } 1088 ksem_dead = 1; 1089 mtx_unlock(&ksem_count_lock); 1090 ksem_module_destroy(); 1091 break; 1092 1093 case MOD_SHUTDOWN: 1094 break; 1095 default: 1096 error = EINVAL; 1097 break; 1098 } 1099 return (error); 1100 } 1101 1102 static moduledata_t sem_mod = { 1103 "sem", 1104 &sem_modload, 1105 NULL 1106 }; 1107 1108 DECLARE_MODULE(sem, sem_mod, SI_SUB_SYSV_SEM, SI_ORDER_FIRST); 1109 MODULE_VERSION(sem, 1); 1110