uipc_sem.c revision 1.37
1 /* $NetBSD: uipc_sem.c,v 1.37 2012/03/09 21:03:46 joerg Exp $ */ 2 3 /*- 4 * Copyright (c) 2011 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Mindaugas Rasiukevicius. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 /* 33 * Copyright (c) 2002 Alfred Perlstein <alfred (at) FreeBSD.org> 34 * All rights reserved. 35 * 36 * Redistribution and use in source and binary forms, with or without 37 * modification, are permitted provided that the following conditions 38 * are met: 39 * 1. Redistributions of source code must retain the above copyright 40 * notice, this list of conditions and the following disclaimer. 41 * 2. Redistributions in binary form must reproduce the above copyright 42 * notice, this list of conditions and the following disclaimer in the 43 * documentation and/or other materials provided with the distribution. 44 * 45 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 46 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 47 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 48 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 49 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 50 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 51 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 52 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 53 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 54 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 55 * SUCH DAMAGE. 56 */ 57 58 /* 59 * Implementation of POSIX semaphore. 60 */ 61 62 #include <sys/cdefs.h> 63 __KERNEL_RCSID(0, "$NetBSD: uipc_sem.c,v 1.37 2012/03/09 21:03:46 joerg Exp $"); 64 65 #include <sys/param.h> 66 #include <sys/kernel.h> 67 68 #include <sys/atomic.h> 69 #include <sys/proc.h> 70 #include <sys/ksem.h> 71 #include <sys/syscall.h> 72 #include <sys/stat.h> 73 #include <sys/kmem.h> 74 #include <sys/fcntl.h> 75 #include <sys/file.h> 76 #include <sys/filedesc.h> 77 #include <sys/kauth.h> 78 #include <sys/module.h> 79 #include <sys/mount.h> 80 #include <sys/syscall.h> 81 #include <sys/syscallargs.h> 82 #include <sys/syscallvar.h> 83 84 MODULE(MODULE_CLASS_MISC, ksem, NULL); 85 86 #define SEM_MAX_NAMELEN 14 87 #define SEM_VALUE_MAX (~0U) 88 89 #define KS_UNLINKED 0x01 90 91 typedef struct ksem { 92 LIST_ENTRY(ksem) ks_entry; /* global list entry */ 93 kmutex_t ks_lock; /* lock on this ksem */ 94 kcondvar_t ks_cv; /* condition variable */ 95 u_int ks_ref; /* number of references */ 96 u_int ks_value; /* current value */ 97 u_int ks_waiters; /* number of waiters */ 98 char * ks_name; /* name, if named */ 99 size_t ks_namelen; /* length of name */ 100 int ks_flags; /* for KS_UNLINKED */ 101 mode_t ks_mode; /* protection bits */ 102 uid_t ks_uid; /* creator uid */ 103 gid_t ks_gid; /* creator gid */ 104 } ksem_t; 105 106 static kmutex_t ksem_lock __cacheline_aligned; 107 static LIST_HEAD(,ksem) ksem_head __cacheline_aligned; 108 static u_int nsems_total __cacheline_aligned; 109 static u_int nsems __cacheline_aligned; 110 111 static int ksem_sysinit(void); 112 static int ksem_sysfini(bool); 113 static int ksem_modcmd(modcmd_t, void *); 114 static int ksem_close_fop(file_t *); 115 116 static const struct fileops semops = { 117 .fo_read = fbadop_read, 118 .fo_write = fbadop_write, 119 .fo_ioctl = fbadop_ioctl, 120 .fo_fcntl = fnullop_fcntl, 121 .fo_poll = fnullop_poll, 122 .fo_stat = fbadop_stat, 123 .fo_close = ksem_close_fop, 124 .fo_kqfilter = fnullop_kqfilter, 125 .fo_restart = fnullop_restart, 126 }; 127 128 static const struct syscall_package ksem_syscalls[] = { 129 { SYS__ksem_init, 0, (sy_call_t *)sys__ksem_init }, 130 { SYS__ksem_open, 0, (sy_call_t *)sys__ksem_open }, 131 { SYS__ksem_unlink, 0, (sy_call_t *)sys__ksem_unlink }, 132 { SYS__ksem_close, 0, (sy_call_t *)sys__ksem_close }, 133 { SYS__ksem_post, 0, (sy_call_t *)sys__ksem_post }, 134 { SYS__ksem_wait, 0, (sy_call_t *)sys__ksem_wait }, 135 { SYS__ksem_trywait, 0, (sy_call_t *)sys__ksem_trywait }, 136 { SYS__ksem_getvalue, 0, (sy_call_t *)sys__ksem_getvalue }, 137 { SYS__ksem_destroy, 0, (sy_call_t *)sys__ksem_destroy }, 138 { SYS__ksem_timedwait, 0, (sy_call_t *)sys__ksem_timedwait }, 139 { 0, 0, NULL }, 140 }; 141 142 static int 143 ksem_sysinit(void) 144 { 145 int error; 146 147 mutex_init(&ksem_lock, MUTEX_DEFAULT, IPL_NONE); 148 LIST_INIT(&ksem_head); 149 nsems_total = 0; 150 nsems = 0; 151 152 error = syscall_establish(NULL, ksem_syscalls); 153 if (error) { 154 (void)ksem_sysfini(false); 155 } 156 return error; 157 } 158 159 static int 160 ksem_sysfini(bool interface) 161 { 162 int error; 163 164 if (interface) { 165 error = syscall_disestablish(NULL, ksem_syscalls); 166 if (error != 0) { 167 return error; 168 } 169 /* 170 * Make sure that no semaphores are in use. Note: semops 171 * must be unused at this point. 172 */ 173 if (nsems_total) { 174 error = syscall_establish(NULL, ksem_syscalls); 175 KASSERT(error == 0); 176 return EBUSY; 177 } 178 } 179 mutex_destroy(&ksem_lock); 180 return 0; 181 } 182 183 static int 184 ksem_modcmd(modcmd_t cmd, void *arg) 185 { 186 187 switch (cmd) { 188 case MODULE_CMD_INIT: 189 return ksem_sysinit(); 190 191 case MODULE_CMD_FINI: 192 return ksem_sysfini(true); 193 194 default: 195 return ENOTTY; 196 } 197 } 198 199 static ksem_t * 200 ksem_lookup(const char *name) 201 { 202 ksem_t *ks; 203 204 KASSERT(mutex_owned(&ksem_lock)); 205 206 LIST_FOREACH(ks, &ksem_head, ks_entry) { 207 if (strcmp(ks->ks_name, name) == 0) { 208 mutex_enter(&ks->ks_lock); 209 return ks; 210 } 211 } 212 return NULL; 213 } 214 215 static int 216 ksem_perm(lwp_t *l, ksem_t *ks) 217 { 218 kauth_cred_t uc = l->l_cred; 219 mode_t mode = ks->ks_mode; 220 221 KASSERT(mutex_owned(&ks->ks_lock)); 222 if ((kauth_cred_geteuid(uc) == ks->ks_uid && (mode & S_IWUSR) != 0) || 223 (kauth_cred_getegid(uc) == ks->ks_gid && (mode & S_IWGRP) != 0) || 224 (mode & S_IWOTH) != 0 || 225 kauth_authorize_generic(uc, KAUTH_GENERIC_ISSUSER, NULL) == 0) 226 return 0; 227 228 return EACCES; 229 } 230 231 /* 232 * ksem_get: get the semaphore from the descriptor. 233 * 234 * => locks the semaphore, if found. 235 * => holds a reference on the file descriptor. 236 */ 237 static int 238 ksem_get(int fd, ksem_t **ksret) 239 { 240 ksem_t *ks; 241 file_t *fp; 242 243 fp = fd_getfile(fd); 244 if (__predict_false(fp == NULL)) 245 return EINVAL; 246 if (__predict_false(fp->f_type != DTYPE_SEM)) { 247 fd_putfile(fd); 248 return EINVAL; 249 } 250 ks = fp->f_data; 251 mutex_enter(&ks->ks_lock); 252 253 *ksret = ks; 254 return 0; 255 } 256 257 /* 258 * ksem_create: allocate and setup a new semaphore structure. 259 */ 260 static int 261 ksem_create(lwp_t *l, const char *name, ksem_t **ksret, mode_t mode, u_int val) 262 { 263 ksem_t *ks; 264 kauth_cred_t uc; 265 char *kname; 266 size_t len; 267 268 /* Pre-check for the limit. */ 269 if (nsems >= ksem_max) { 270 return ENFILE; 271 } 272 273 if (val > SEM_VALUE_MAX) { 274 return EINVAL; 275 } 276 277 if (name != NULL) { 278 len = strlen(name); 279 if (len > SEM_MAX_NAMELEN) { 280 return ENAMETOOLONG; 281 } 282 /* Name must start with a '/' but not contain one. */ 283 if (*name != '/' || len < 2 || strchr(name + 1, '/') != NULL) { 284 return EINVAL; 285 } 286 kname = kmem_alloc(++len, KM_SLEEP); 287 strlcpy(kname, name, len); 288 } else { 289 kname = NULL; 290 len = 0; 291 } 292 293 ks = kmem_zalloc(sizeof(ksem_t), KM_SLEEP); 294 mutex_init(&ks->ks_lock, MUTEX_DEFAULT, IPL_NONE); 295 cv_init(&ks->ks_cv, "psem"); 296 ks->ks_name = kname; 297 ks->ks_namelen = len; 298 ks->ks_mode = mode; 299 ks->ks_value = val; 300 ks->ks_ref = 1; 301 302 uc = l->l_cred; 303 ks->ks_uid = kauth_cred_geteuid(uc); 304 ks->ks_gid = kauth_cred_getegid(uc); 305 306 atomic_inc_uint(&nsems_total); 307 *ksret = ks; 308 return 0; 309 } 310 311 static void 312 ksem_free(ksem_t *ks) 313 { 314 315 KASSERT(!cv_has_waiters(&ks->ks_cv)); 316 317 if (ks->ks_name) { 318 KASSERT(ks->ks_namelen > 0); 319 kmem_free(ks->ks_name, ks->ks_namelen); 320 } 321 mutex_destroy(&ks->ks_lock); 322 cv_destroy(&ks->ks_cv); 323 kmem_free(ks, sizeof(ksem_t)); 324 325 atomic_dec_uint(&nsems_total); 326 } 327 328 int 329 sys__ksem_init(struct lwp *l, const struct sys__ksem_init_args *uap, 330 register_t *retval) 331 { 332 /* { 333 unsigned int value; 334 intptr_t *idp; 335 } */ 336 337 return do_ksem_init(l, SCARG(uap, value), SCARG(uap, idp), copyout); 338 } 339 340 int 341 do_ksem_init(lwp_t *l, u_int val, intptr_t *idp, copyout_t docopyout) 342 { 343 proc_t *p = l->l_proc; 344 ksem_t *ks; 345 file_t *fp; 346 intptr_t id; 347 int fd, error; 348 349 error = fd_allocfile(&fp, &fd); 350 if (error) { 351 return error; 352 } 353 fp->f_type = DTYPE_SEM; 354 fp->f_flag = FREAD | FWRITE; 355 fp->f_ops = &semops; 356 357 id = (intptr_t)fd; 358 error = (*docopyout)(&id, idp, sizeof(*idp)); 359 if (error) { 360 fd_abort(p, fp, fd); 361 return error; 362 } 363 364 /* Note the mode does not matter for anonymous semaphores. */ 365 error = ksem_create(l, NULL, &ks, 0, val); 366 if (error) { 367 fd_abort(p, fp, fd); 368 return error; 369 } 370 fp->f_data = ks; 371 fd_affix(p, fp, fd); 372 return error; 373 } 374 375 int 376 sys__ksem_open(struct lwp *l, const struct sys__ksem_open_args *uap, 377 register_t *retval) 378 { 379 /* { 380 const char *name; 381 int oflag; 382 mode_t mode; 383 unsigned int value; 384 intptr_t *idp; 385 } */ 386 387 return do_ksem_open(l, SCARG(uap, name), SCARG(uap, oflag), 388 SCARG(uap, mode), SCARG(uap, value), SCARG(uap, idp), copyout); 389 } 390 391 int 392 do_ksem_open(struct lwp *l, const char *semname, int oflag, mode_t mode, 393 unsigned int value, intptr_t *idp, copyout_t docopyout) 394 { 395 char name[SEM_MAX_NAMELEN + 1]; 396 proc_t *p = l->l_proc; 397 ksem_t *ksnew = NULL, *ks; 398 file_t *fp; 399 intptr_t id; 400 int fd, error; 401 402 error = copyinstr(semname, name, sizeof(name), NULL); 403 if (error) { 404 return error; 405 } 406 error = fd_allocfile(&fp, &fd); 407 if (error) { 408 return error; 409 } 410 fp->f_type = DTYPE_SEM; 411 fp->f_flag = FREAD | FWRITE; 412 fp->f_ops = &semops; 413 414 /* 415 * The ID (file descriptor number) can be stored early. 416 * Note that zero is a special value for libpthread. 417 */ 418 id = (intptr_t)fd; 419 error = (*docopyout)(&id, idp, sizeof(*idp)); 420 if (error) { 421 goto err; 422 } 423 424 if (oflag & O_CREAT) { 425 /* Create a new semaphore. */ 426 error = ksem_create(l, name, &ksnew, mode, value); 427 if (error) { 428 goto err; 429 } 430 KASSERT(ksnew != NULL); 431 } 432 433 /* Lookup for a semaphore with such name. */ 434 mutex_enter(&ksem_lock); 435 ks = ksem_lookup(name); 436 if (ks) { 437 KASSERT(mutex_owned(&ks->ks_lock)); 438 mutex_exit(&ksem_lock); 439 440 /* Check for exclusive create. */ 441 if (oflag & O_EXCL) { 442 mutex_exit(&ks->ks_lock); 443 error = EEXIST; 444 goto err; 445 } 446 /* 447 * Verify permissions. If we can access it, 448 * add the reference of this thread. 449 */ 450 error = ksem_perm(l, ks); 451 if (error == 0) { 452 ks->ks_ref++; 453 } 454 mutex_exit(&ks->ks_lock); 455 if (error) { 456 goto err; 457 } 458 } else { 459 /* Fail if not found and not creating. */ 460 if ((oflag & O_CREAT) == 0) { 461 mutex_exit(&ksem_lock); 462 KASSERT(ksnew == NULL); 463 error = ENOENT; 464 goto err; 465 } 466 467 /* Check for the limit locked. */ 468 if (nsems >= ksem_max) { 469 mutex_exit(&ksem_lock); 470 error = ENFILE; 471 goto err; 472 } 473 474 /* 475 * Finally, insert semaphore into the list. 476 * Note: it already has the initial reference. 477 */ 478 ks = ksnew; 479 LIST_INSERT_HEAD(&ksem_head, ks, ks_entry); 480 nsems++; 481 mutex_exit(&ksem_lock); 482 483 ksnew = NULL; 484 } 485 KASSERT(ks != NULL); 486 fp->f_data = ks; 487 fd_affix(p, fp, fd); 488 err: 489 if (error) { 490 fd_abort(p, fp, fd); 491 } 492 if (ksnew) { 493 ksem_free(ksnew); 494 } 495 return error; 496 } 497 498 int 499 sys__ksem_close(struct lwp *l, const struct sys__ksem_close_args *uap, 500 register_t *retval) 501 { 502 /* { 503 intptr_t id; 504 } */ 505 int fd = (int)SCARG(uap, id); 506 507 if (fd_getfile(fd) == NULL) { 508 return EBADF; 509 } 510 return fd_close(fd); 511 } 512 513 static int 514 ksem_close_fop(file_t *fp) 515 { 516 ksem_t *ks = fp->f_data; 517 bool destroy = false; 518 519 mutex_enter(&ks->ks_lock); 520 KASSERT(ks->ks_ref > 0); 521 if (--ks->ks_ref == 0) { 522 /* 523 * Destroy if the last reference and semaphore is unnamed, 524 * or unlinked (for named semaphore). 525 */ 526 destroy = (ks->ks_flags & KS_UNLINKED) || (ks->ks_name == NULL); 527 } 528 mutex_exit(&ks->ks_lock); 529 530 if (destroy) { 531 ksem_free(ks); 532 } 533 return 0; 534 } 535 536 int 537 sys__ksem_unlink(struct lwp *l, const struct sys__ksem_unlink_args *uap, 538 register_t *retval) 539 { 540 /* { 541 const char *name; 542 } */ 543 char name[SEM_MAX_NAMELEN + 1]; 544 ksem_t *ks; 545 u_int refcnt; 546 int error; 547 548 error = copyinstr(SCARG(uap, name), name, sizeof(name), NULL); 549 if (error) 550 return error; 551 552 mutex_enter(&ksem_lock); 553 ks = ksem_lookup(name); 554 if (ks == NULL) { 555 mutex_exit(&ksem_lock); 556 return ENOENT; 557 } 558 KASSERT(mutex_owned(&ks->ks_lock)); 559 560 /* Verify permissions. */ 561 error = ksem_perm(l, ks); 562 if (error) { 563 mutex_exit(&ks->ks_lock); 564 mutex_exit(&ksem_lock); 565 return error; 566 } 567 568 /* Remove from the global list. */ 569 LIST_REMOVE(ks, ks_entry); 570 nsems--; 571 mutex_exit(&ksem_lock); 572 573 refcnt = ks->ks_ref; 574 if (refcnt) { 575 /* Mark as unlinked, if there are references. */ 576 ks->ks_flags |= KS_UNLINKED; 577 } 578 mutex_exit(&ks->ks_lock); 579 580 if (refcnt == 0) { 581 ksem_free(ks); 582 } 583 return 0; 584 } 585 586 int 587 sys__ksem_post(struct lwp *l, const struct sys__ksem_post_args *uap, 588 register_t *retval) 589 { 590 /* { 591 intptr_t id; 592 } */ 593 int fd = (int)SCARG(uap, id), error; 594 ksem_t *ks; 595 596 error = ksem_get(fd, &ks); 597 if (error) { 598 return error; 599 } 600 KASSERT(mutex_owned(&ks->ks_lock)); 601 if (ks->ks_value == SEM_VALUE_MAX) { 602 error = EOVERFLOW; 603 goto out; 604 } 605 ks->ks_value++; 606 if (ks->ks_waiters) { 607 cv_broadcast(&ks->ks_cv); 608 } 609 out: 610 mutex_exit(&ks->ks_lock); 611 fd_putfile(fd); 612 return error; 613 } 614 615 int 616 do_ksem_wait(lwp_t *l, intptr_t id, bool try, struct timespec *abstime) 617 { 618 int fd = (int)id, error, timeo; 619 ksem_t *ks; 620 621 error = ksem_get(fd, &ks); 622 if (error) { 623 return error; 624 } 625 KASSERT(mutex_owned(&ks->ks_lock)); 626 while (ks->ks_value == 0) { 627 ks->ks_waiters++; 628 if (!try && abstime != NULL) { 629 error = abstimeout2timo(abstime, &timeo); 630 if (error != 0) 631 goto out; 632 } else { 633 timeo = 0; 634 } 635 error = try ? EAGAIN : cv_timedwait_sig(&ks->ks_cv, 636 &ks->ks_lock, timeo); 637 ks->ks_waiters--; 638 if (error) 639 goto out; 640 } 641 ks->ks_value--; 642 out: 643 mutex_exit(&ks->ks_lock); 644 fd_putfile(fd); 645 return error; 646 } 647 648 int 649 sys__ksem_wait(struct lwp *l, const struct sys__ksem_wait_args *uap, 650 register_t *retval) 651 { 652 /* { 653 intptr_t id; 654 } */ 655 656 return do_ksem_wait(l, SCARG(uap, id), false, NULL); 657 } 658 659 int 660 sys__ksem_timedwait(struct lwp *l, const struct sys__ksem_timedwait_args *uap, 661 register_t *retval) 662 { 663 /* { 664 intptr_t id; 665 const struct timespec *abstime; 666 } */ 667 struct timespec ts; 668 int error; 669 670 error = copyin(SCARG(uap, abstime), &ts, sizeof(ts)); 671 if (error != 0) 672 return error; 673 674 if (ts.tv_sec < 0 || ts.tv_nsec < 0 || ts.tv_nsec >= 1000000000) 675 return EINVAL; 676 677 error = do_ksem_wait(l, SCARG(uap, id), false, &ts); 678 if (error == EWOULDBLOCK) 679 error = ETIMEDOUT; 680 return error; 681 } 682 683 int 684 sys__ksem_trywait(struct lwp *l, const struct sys__ksem_trywait_args *uap, 685 register_t *retval) 686 { 687 /* { 688 intptr_t id; 689 } */ 690 691 return do_ksem_wait(l, SCARG(uap, id), true, NULL); 692 } 693 694 int 695 sys__ksem_getvalue(struct lwp *l, const struct sys__ksem_getvalue_args *uap, 696 register_t *retval) 697 { 698 /* { 699 intptr_t id; 700 unsigned int *value; 701 } */ 702 int fd = (int)SCARG(uap, id), error; 703 ksem_t *ks; 704 unsigned int val; 705 706 error = ksem_get(fd, &ks); 707 if (error) { 708 return error; 709 } 710 KASSERT(mutex_owned(&ks->ks_lock)); 711 val = ks->ks_value; 712 mutex_exit(&ks->ks_lock); 713 fd_putfile(fd); 714 715 return copyout(&val, SCARG(uap, value), sizeof(val)); 716 } 717 718 int 719 sys__ksem_destroy(struct lwp *l, const struct sys__ksem_destroy_args *uap, 720 register_t *retval) 721 { 722 /* { 723 intptr_t id; 724 } */ 725 int fd = (int)SCARG(uap, id), error; 726 ksem_t *ks; 727 728 error = ksem_get(fd, &ks); 729 if (error) { 730 return error; 731 } 732 KASSERT(mutex_owned(&ks->ks_lock)); 733 734 /* Operation is only for unnamed semaphores. */ 735 if (ks->ks_name != NULL) { 736 error = EINVAL; 737 goto out; 738 } 739 /* Cannot destroy if there are waiters. */ 740 if (ks->ks_waiters) { 741 error = EBUSY; 742 goto out; 743 } 744 out: 745 mutex_exit(&ks->ks_lock); 746 if (error) { 747 fd_putfile(fd); 748 return error; 749 } 750 return fd_close(fd); 751 } 752
Indexes created Tue Sep 23 22:09:46 GMT 2025