1 /*- 2 * Implementation of SVID semaphores 3 * 4 * Author: Daniel Boulet 5 * 6 * This software is provided ``AS IS'' without any warranties of any kind. 7 */ 8 /*- 9 * Copyright (c) 2003-2005 McAfee, Inc. 10 * All rights reserved. 11 * 12 * This software was developed for the FreeBSD Project in part by McAfee 13 * Research, the Security Research Division of McAfee, Inc under DARPA/SPAWAR 14 * contract N66001-01-C-8035 ("CBOSS"), as part of the DARPA CHATS research 15 * program. 16 * 17 * Redistribution and use in source and binary forms, with or without 18 * modification, are permitted provided that the following conditions 19 * are met: 20 * 1. Redistributions of source code must retain the above copyright 21 * notice, this list of conditions and the following disclaimer. 22 * 2. Redistributions in binary form must reproduce the above copyright 23 * notice, this list of conditions and the following disclaimer in the 24 * documentation and/or other materials provided with the distribution. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 */ 38 39 #include <sys/cdefs.h> 40 __FBSDID("$FreeBSD$"); 41 42 #include "opt_sysvipc.h" 43 #include "opt_mac.h" 44 45 #include <sys/param.h> 46 #include <sys/systm.h> 47 #include <sys/sysproto.h> 48 #include <sys/eventhandler.h> 49 #include <sys/kernel.h> 50 #include <sys/proc.h> 51 #include <sys/lock.h> 52 #include <sys/module.h> 53 #include <sys/mutex.h> 54 #include <sys/sem.h> 55 #include <sys/syscall.h> 56 #include <sys/sysent.h> 57 #include <sys/sysctl.h> 58 #include <sys/malloc.h> 59 #include <sys/jail.h> 60 #include <sys/mac.h> 61 62 static MALLOC_DEFINE(M_SEM, "sem", "SVID compatible semaphores"); 63 64 #ifdef SEM_DEBUG 65 #define DPRINTF(a) printf a 66 #else 67 #define DPRINTF(a) 68 #endif 69 #ifdef MAC_DEBUG 70 #define MPRINTF(a) printf a 71 #else 72 #define MPRINTF(a) 73 #endif 74 75 static void seminit(void); 76 static int sysvsem_modload(struct module *, int, void *); 77 static int semunload(void); 78 static void semexit_myhook(void *arg, struct proc *p); 79 static int sysctl_sema(SYSCTL_HANDLER_ARGS); 80 static int semvalid(int semid, struct semid_kernel *semakptr); 81 82 #ifndef _SYS_SYSPROTO_H_ 83 struct __semctl_args; 84 int __semctl(struct thread *td, struct __semctl_args *uap); 85 struct semget_args; 86 int semget(struct thread *td, struct semget_args *uap); 87 struct semop_args; 88 int semop(struct thread *td, struct semop_args *uap); 89 #endif 90 91 static struct sem_undo *semu_alloc(struct thread *td); 92 static int semundo_adjust(struct thread *td, struct sem_undo **supptr, 93 int semid, int semnum, int adjval); 94 static void semundo_clear(int semid, int semnum); 95 96 /* XXX casting to (sy_call_t *) is bogus, as usual. */ 97 static sy_call_t *semcalls[] = { 98 (sy_call_t *)__semctl, (sy_call_t *)semget, 99 (sy_call_t *)semop 100 }; 101 102 static struct mtx sem_mtx; /* semaphore global lock */ 103 static int semtot = 0; 104 static struct semid_kernel *sema; /* semaphore id pool */ 105 static struct mtx *sema_mtx; /* semaphore id pool mutexes*/ 106 static struct sem *sem; /* semaphore pool */ 107 SLIST_HEAD(, sem_undo) semu_list; /* list of active undo structures */ 108 static int *semu; /* undo structure pool */ 109 static eventhandler_tag semexit_tag; 110 111 #define SEMUNDO_MTX sem_mtx 112 #define SEMUNDO_LOCK() mtx_lock(&SEMUNDO_MTX); 113 #define SEMUNDO_UNLOCK() mtx_unlock(&SEMUNDO_MTX); 114 #define SEMUNDO_LOCKASSERT(how) mtx_assert(&SEMUNDO_MTX, (how)); 115 116 struct sem { 117 u_short semval; /* semaphore value */ 118 pid_t sempid; /* pid of last operation */ 119 u_short semncnt; /* # awaiting semval > cval */ 120 u_short semzcnt; /* # awaiting semval = 0 */ 121 }; 122 123 /* 124 * Undo structure (one per process) 125 */ 126 struct sem_undo { 127 SLIST_ENTRY(sem_undo) un_next; /* ptr to next active undo structure */ 128 struct proc *un_proc; /* owner of this structure */ 129 short un_cnt; /* # of active entries */ 130 struct undo { 131 short un_adjval; /* adjust on exit values */ 132 short un_num; /* semaphore # */ 133 int un_id; /* semid */ 134 } un_ent[1]; /* undo entries */ 135 }; 136 137 /* 138 * Configuration parameters 139 */ 140 #ifndef SEMMNI 141 #define SEMMNI 10 /* # of semaphore identifiers */ 142 #endif 143 #ifndef SEMMNS 144 #define SEMMNS 60 /* # of semaphores in system */ 145 #endif 146 #ifndef SEMUME 147 #define SEMUME 10 /* max # of undo entries per process */ 148 #endif 149 #ifndef SEMMNU 150 #define SEMMNU 30 /* # of undo structures in system */ 151 #endif 152 153 /* shouldn't need tuning */ 154 #ifndef SEMMAP 155 #define SEMMAP 30 /* # of entries in semaphore map */ 156 #endif 157 #ifndef SEMMSL 158 #define SEMMSL SEMMNS /* max # of semaphores per id */ 159 #endif 160 #ifndef SEMOPM 161 #define SEMOPM 100 /* max # of operations per semop call */ 162 #endif 163 164 #define SEMVMX 32767 /* semaphore maximum value */ 165 #define SEMAEM 16384 /* adjust on exit max value */ 166 167 /* 168 * Due to the way semaphore memory is allocated, we have to ensure that 169 * SEMUSZ is properly aligned. 170 */ 171 172 #define SEM_ALIGN(bytes) (((bytes) + (sizeof(long) - 1)) & ~(sizeof(long) - 1)) 173 174 /* actual size of an undo structure */ 175 #define SEMUSZ SEM_ALIGN(offsetof(struct sem_undo, un_ent[SEMUME])) 176 177 /* 178 * Macro to find a particular sem_undo vector 179 */ 180 #define SEMU(ix) \ 181 ((struct sem_undo *)(((intptr_t)semu)+ix * seminfo.semusz)) 182 183 /* 184 * semaphore info struct 185 */ 186 struct seminfo seminfo = { 187 SEMMAP, /* # of entries in semaphore map */ 188 SEMMNI, /* # of semaphore identifiers */ 189 SEMMNS, /* # of semaphores in system */ 190 SEMMNU, /* # of undo structures in system */ 191 SEMMSL, /* max # of semaphores per id */ 192 SEMOPM, /* max # of operations per semop call */ 193 SEMUME, /* max # of undo entries per process */ 194 SEMUSZ, /* size in bytes of undo structure */ 195 SEMVMX, /* semaphore maximum value */ 196 SEMAEM /* adjust on exit max value */ 197 }; 198 199 SYSCTL_DECL(_kern_ipc); 200 SYSCTL_INT(_kern_ipc, OID_AUTO, semmap, CTLFLAG_RW, &seminfo.semmap, 0, ""); 201 SYSCTL_INT(_kern_ipc, OID_AUTO, semmni, CTLFLAG_RDTUN, &seminfo.semmni, 0, ""); 202 SYSCTL_INT(_kern_ipc, OID_AUTO, semmns, CTLFLAG_RDTUN, &seminfo.semmns, 0, ""); 203 SYSCTL_INT(_kern_ipc, OID_AUTO, semmnu, CTLFLAG_RDTUN, &seminfo.semmnu, 0, ""); 204 SYSCTL_INT(_kern_ipc, OID_AUTO, semmsl, CTLFLAG_RW, &seminfo.semmsl, 0, ""); 205 SYSCTL_INT(_kern_ipc, OID_AUTO, semopm, CTLFLAG_RDTUN, &seminfo.semopm, 0, ""); 206 SYSCTL_INT(_kern_ipc, OID_AUTO, semume, CTLFLAG_RDTUN, &seminfo.semume, 0, ""); 207 SYSCTL_INT(_kern_ipc, OID_AUTO, semusz, CTLFLAG_RDTUN, &seminfo.semusz, 0, ""); 208 SYSCTL_INT(_kern_ipc, OID_AUTO, semvmx, CTLFLAG_RW, &seminfo.semvmx, 0, ""); 209 SYSCTL_INT(_kern_ipc, OID_AUTO, semaem, CTLFLAG_RW, &seminfo.semaem, 0, ""); 210 SYSCTL_PROC(_kern_ipc, OID_AUTO, sema, CTLFLAG_RD, 211 NULL, 0, sysctl_sema, "", ""); 212 213 static void 214 seminit(void) 215 { 216 int i; 217 218 TUNABLE_INT_FETCH("kern.ipc.semmap", &seminfo.semmap); 219 TUNABLE_INT_FETCH("kern.ipc.semmni", &seminfo.semmni); 220 TUNABLE_INT_FETCH("kern.ipc.semmns", &seminfo.semmns); 221 TUNABLE_INT_FETCH("kern.ipc.semmnu", &seminfo.semmnu); 222 TUNABLE_INT_FETCH("kern.ipc.semmsl", &seminfo.semmsl); 223 TUNABLE_INT_FETCH("kern.ipc.semopm", &seminfo.semopm); 224 TUNABLE_INT_FETCH("kern.ipc.semume", &seminfo.semume); 225 TUNABLE_INT_FETCH("kern.ipc.semusz", &seminfo.semusz); 226 TUNABLE_INT_FETCH("kern.ipc.semvmx", &seminfo.semvmx); 227 TUNABLE_INT_FETCH("kern.ipc.semaem", &seminfo.semaem); 228 229 sem = malloc(sizeof(struct sem) * seminfo.semmns, M_SEM, M_WAITOK); 230 sema = malloc(sizeof(struct semid_kernel) * seminfo.semmni, M_SEM, 231 M_WAITOK); 232 sema_mtx = malloc(sizeof(struct mtx) * seminfo.semmni, M_SEM, 233 M_WAITOK | M_ZERO); 234 semu = malloc(seminfo.semmnu * seminfo.semusz, M_SEM, M_WAITOK); 235 236 for (i = 0; i < seminfo.semmni; i++) { 237 sema[i].u.sem_base = 0; 238 sema[i].u.sem_perm.mode = 0; 239 sema[i].u.sem_perm.seq = 0; 240 #ifdef MAC 241 mac_init_sysv_sema(&sema[i]); 242 #endif 243 } 244 for (i = 0; i < seminfo.semmni; i++) 245 mtx_init(&sema_mtx[i], "semid", NULL, MTX_DEF); 246 for (i = 0; i < seminfo.semmnu; i++) { 247 struct sem_undo *suptr = SEMU(i); 248 suptr->un_proc = NULL; 249 } 250 SLIST_INIT(&semu_list); 251 mtx_init(&sem_mtx, "sem", NULL, MTX_DEF); 252 semexit_tag = EVENTHANDLER_REGISTER(process_exit, semexit_myhook, NULL, 253 EVENTHANDLER_PRI_ANY); 254 } 255 256 static int 257 semunload(void) 258 { 259 int i; 260 261 if (semtot != 0) 262 return (EBUSY); 263 264 EVENTHANDLER_DEREGISTER(process_exit, semexit_tag); 265 #ifdef MAC 266 for (i = 0; i < seminfo.semmni; i++) 267 mac_destroy_sysv_sema(&sema[i]); 268 #endif 269 free(sem, M_SEM); 270 free(sema, M_SEM); 271 free(semu, M_SEM); 272 for (i = 0; i < seminfo.semmni; i++) 273 mtx_destroy(&sema_mtx[i]); 274 mtx_destroy(&sem_mtx); 275 return (0); 276 } 277 278 static int 279 sysvsem_modload(struct module *module, int cmd, void *arg) 280 { 281 int error = 0; 282 283 switch (cmd) { 284 case MOD_LOAD: 285 seminit(); 286 break; 287 case MOD_UNLOAD: 288 error = semunload(); 289 break; 290 case MOD_SHUTDOWN: 291 break; 292 default: 293 error = EINVAL; 294 break; 295 } 296 return (error); 297 } 298 299 static moduledata_t sysvsem_mod = { 300 "sysvsem", 301 &sysvsem_modload, 302 NULL 303 }; 304 305 SYSCALL_MODULE_HELPER(semsys); 306 SYSCALL_MODULE_HELPER(__semctl); 307 SYSCALL_MODULE_HELPER(semget); 308 SYSCALL_MODULE_HELPER(semop); 309 310 DECLARE_MODULE(sysvsem, sysvsem_mod, 311 SI_SUB_SYSV_SEM, SI_ORDER_FIRST); 312 MODULE_VERSION(sysvsem, 1); 313 314 /* 315 * Entry point for all SEM calls 316 * 317 * MPSAFE 318 */ 319 int 320 semsys(td, uap) 321 struct thread *td; 322 /* XXX actually varargs. */ 323 struct semsys_args /* { 324 int which; 325 int a2; 326 int a3; 327 int a4; 328 int a5; 329 } */ *uap; 330 { 331 int error; 332 333 if (!jail_sysvipc_allowed && jailed(td->td_ucred)) 334 return (ENOSYS); 335 if (uap->which < 0 || 336 uap->which >= sizeof(semcalls)/sizeof(semcalls[0])) 337 return (EINVAL); 338 error = (*semcalls[uap->which])(td, &uap->a2); 339 return (error); 340 } 341 342 /* 343 * Allocate a new sem_undo structure for a process 344 * (returns ptr to structure or NULL if no more room) 345 */ 346 347 static struct sem_undo * 348 semu_alloc(td) 349 struct thread *td; 350 { 351 int i; 352 struct sem_undo *suptr; 353 struct sem_undo **supptr; 354 int attempt; 355 356 SEMUNDO_LOCKASSERT(MA_OWNED); 357 /* 358 * Try twice to allocate something. 359 * (we'll purge an empty structure after the first pass so 360 * two passes are always enough) 361 */ 362 363 for (attempt = 0; attempt < 2; attempt++) { 364 /* 365 * Look for a free structure. 366 * Fill it in and return it if we find one. 367 */ 368 369 for (i = 0; i < seminfo.semmnu; i++) { 370 suptr = SEMU(i); 371 if (suptr->un_proc == NULL) { 372 SLIST_INSERT_HEAD(&semu_list, suptr, un_next); 373 suptr->un_cnt = 0; 374 suptr->un_proc = td->td_proc; 375 return(suptr); 376 } 377 } 378 379 /* 380 * We didn't find a free one, if this is the first attempt 381 * then try to free a structure. 382 */ 383 384 if (attempt == 0) { 385 /* All the structures are in use - try to free one */ 386 int did_something = 0; 387 388 SLIST_FOREACH_PREVPTR(suptr, supptr, &semu_list, 389 un_next) { 390 if (suptr->un_cnt == 0) { 391 suptr->un_proc = NULL; 392 did_something = 1; 393 *supptr = SLIST_NEXT(suptr, un_next); 394 break; 395 } 396 } 397 398 /* If we didn't free anything then just give-up */ 399 if (!did_something) 400 return(NULL); 401 } else { 402 /* 403 * The second pass failed even though we freed 404 * something after the first pass! 405 * This is IMPOSSIBLE! 406 */ 407 panic("semu_alloc - second attempt failed"); 408 } 409 } 410 return (NULL); 411 } 412 413 /* 414 * Adjust a particular entry for a particular proc 415 */ 416 417 static int 418 semundo_adjust(td, supptr, semid, semnum, adjval) 419 struct thread *td; 420 struct sem_undo **supptr; 421 int semid, semnum; 422 int adjval; 423 { 424 struct proc *p = td->td_proc; 425 struct sem_undo *suptr; 426 struct undo *sunptr; 427 int i; 428 429 SEMUNDO_LOCKASSERT(MA_OWNED); 430 /* Look for and remember the sem_undo if the caller doesn't provide 431 it */ 432 433 suptr = *supptr; 434 if (suptr == NULL) { 435 SLIST_FOREACH(suptr, &semu_list, un_next) { 436 if (suptr->un_proc == p) { 437 *supptr = suptr; 438 break; 439 } 440 } 441 if (suptr == NULL) { 442 if (adjval == 0) 443 return(0); 444 suptr = semu_alloc(td); 445 if (suptr == NULL) 446 return(ENOSPC); 447 *supptr = suptr; 448 } 449 } 450 451 /* 452 * Look for the requested entry and adjust it (delete if adjval becomes 453 * 0). 454 */ 455 sunptr = &suptr->un_ent[0]; 456 for (i = 0; i < suptr->un_cnt; i++, sunptr++) { 457 if (sunptr->un_id != semid || sunptr->un_num != semnum) 458 continue; 459 if (adjval != 0) { 460 adjval += sunptr->un_adjval; 461 if (adjval > seminfo.semaem || adjval < -seminfo.semaem) 462 return (ERANGE); 463 } 464 sunptr->un_adjval = adjval; 465 if (sunptr->un_adjval == 0) { 466 suptr->un_cnt--; 467 if (i < suptr->un_cnt) 468 suptr->un_ent[i] = 469 suptr->un_ent[suptr->un_cnt]; 470 } 471 return(0); 472 } 473 474 /* Didn't find the right entry - create it */ 475 if (adjval == 0) 476 return(0); 477 if (adjval > seminfo.semaem || adjval < -seminfo.semaem) 478 return (ERANGE); 479 if (suptr->un_cnt != seminfo.semume) { 480 sunptr = &suptr->un_ent[suptr->un_cnt]; 481 suptr->un_cnt++; 482 sunptr->un_adjval = adjval; 483 sunptr->un_id = semid; sunptr->un_num = semnum; 484 } else 485 return(EINVAL); 486 return(0); 487 } 488 489 static void 490 semundo_clear(semid, semnum) 491 int semid, semnum; 492 { 493 struct sem_undo *suptr; 494 495 SEMUNDO_LOCKASSERT(MA_OWNED); 496 SLIST_FOREACH(suptr, &semu_list, un_next) { 497 struct undo *sunptr = &suptr->un_ent[0]; 498 int i = 0; 499 500 while (i < suptr->un_cnt) { 501 if (sunptr->un_id == semid) { 502 if (semnum == -1 || sunptr->un_num == semnum) { 503 suptr->un_cnt--; 504 if (i < suptr->un_cnt) { 505 suptr->un_ent[i] = 506 suptr->un_ent[suptr->un_cnt]; 507 continue; 508 } 509 } 510 if (semnum != -1) 511 break; 512 } 513 i++, sunptr++; 514 } 515 } 516 } 517 518 static int 519 semvalid(semid, semakptr) 520 int semid; 521 struct semid_kernel *semakptr; 522 { 523 524 return ((semakptr->u.sem_perm.mode & SEM_ALLOC) == 0 || 525 semakptr->u.sem_perm.seq != IPCID_TO_SEQ(semid) ? EINVAL : 0); 526 } 527 528 /* 529 * Note that the user-mode half of this passes a union, not a pointer 530 */ 531 #ifndef _SYS_SYSPROTO_H_ 532 struct __semctl_args { 533 int semid; 534 int semnum; 535 int cmd; 536 union semun *arg; 537 }; 538 #endif 539 540 /* 541 * MPSAFE 542 */ 543 int 544 __semctl(td, uap) 545 struct thread *td; 546 struct __semctl_args *uap; 547 { 548 int semid = uap->semid; 549 int semnum = uap->semnum; 550 int cmd = uap->cmd; 551 u_short *array; 552 union semun *arg = uap->arg; 553 union semun real_arg; 554 struct ucred *cred = td->td_ucred; 555 int i, rval, error; 556 struct semid_ds sbuf; 557 struct semid_kernel *semakptr; 558 struct mtx *sema_mtxp; 559 u_short usval, count; 560 561 DPRINTF(("call to semctl(%d, %d, %d, 0x%x)\n", 562 semid, semnum, cmd, arg)); 563 if (!jail_sysvipc_allowed && jailed(td->td_ucred)) 564 return (ENOSYS); 565 566 array = NULL; 567 568 switch(cmd) { 569 case SEM_STAT: 570 if (semid < 0 || semid >= seminfo.semmni) 571 return (EINVAL); 572 if ((error = copyin(arg, &real_arg, sizeof(real_arg))) != 0) 573 return (error); 574 semakptr = &sema[semid]; 575 sema_mtxp = &sema_mtx[semid]; 576 mtx_lock(sema_mtxp); 577 if ((semakptr->u.sem_perm.mode & SEM_ALLOC) == 0) { 578 error = EINVAL; 579 goto done2; 580 } 581 if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_R))) 582 goto done2; 583 #ifdef MAC 584 error = mac_check_sysv_semctl(cred, semakptr, cmd); 585 if (error != 0) { 586 MPRINTF(("mac_check_sysv_semctl returned %d\n", 587 error)); 588 goto done2; 589 } 590 #endif 591 mtx_unlock(sema_mtxp); 592 error = copyout(&semakptr->u, real_arg.buf, 593 sizeof(struct semid_ds)); 594 rval = IXSEQ_TO_IPCID(semid, semakptr->u.sem_perm); 595 if (error == 0) 596 td->td_retval[0] = rval; 597 return (error); 598 } 599 600 semid = IPCID_TO_IX(semid); 601 if (semid < 0 || semid >= seminfo.semmni) 602 return (EINVAL); 603 604 semakptr = &sema[semid]; 605 sema_mtxp = &sema_mtx[semid]; 606 #ifdef MAC 607 mtx_lock(sema_mtxp); 608 error = mac_check_sysv_semctl(cred, semakptr, cmd); 609 if (error != 0) { 610 MPRINTF(("mac_check_sysv_semctl returned %d\n", error)); 611 mtx_unlock(sema_mtxp); 612 return (error); 613 } 614 mtx_unlock(sema_mtxp); 615 #endif 616 617 error = 0; 618 rval = 0; 619 620 switch (cmd) { 621 case IPC_RMID: 622 mtx_lock(sema_mtxp); 623 if ((error = semvalid(uap->semid, semakptr)) != 0) 624 goto done2; 625 if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_M))) 626 goto done2; 627 semakptr->u.sem_perm.cuid = cred->cr_uid; 628 semakptr->u.sem_perm.uid = cred->cr_uid; 629 semtot -= semakptr->u.sem_nsems; 630 for (i = semakptr->u.sem_base - sem; i < semtot; i++) 631 sem[i] = sem[i + semakptr->u.sem_nsems]; 632 for (i = 0; i < seminfo.semmni; i++) { 633 if ((sema[i].u.sem_perm.mode & SEM_ALLOC) && 634 sema[i].u.sem_base > semakptr->u.sem_base) 635 sema[i].u.sem_base -= semakptr->u.sem_nsems; 636 } 637 semakptr->u.sem_perm.mode = 0; 638 #ifdef MAC 639 mac_cleanup_sysv_sema(semakptr); 640 #endif 641 SEMUNDO_LOCK(); 642 semundo_clear(semid, -1); 643 SEMUNDO_UNLOCK(); 644 wakeup(semakptr); 645 break; 646 647 case IPC_SET: 648 if ((error = copyin(arg, &real_arg, sizeof(real_arg))) != 0) 649 goto done2; 650 if ((error = copyin(real_arg.buf, &sbuf, sizeof(sbuf))) != 0) 651 goto done2; 652 mtx_lock(sema_mtxp); 653 if ((error = semvalid(uap->semid, semakptr)) != 0) 654 goto done2; 655 if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_M))) 656 goto done2; 657 semakptr->u.sem_perm.uid = sbuf.sem_perm.uid; 658 semakptr->u.sem_perm.gid = sbuf.sem_perm.gid; 659 semakptr->u.sem_perm.mode = (semakptr->u.sem_perm.mode & 660 ~0777) | (sbuf.sem_perm.mode & 0777); 661 semakptr->u.sem_ctime = time_second; 662 break; 663 664 case IPC_STAT: 665 if ((error = copyin(arg, &real_arg, sizeof(real_arg))) != 0) 666 goto done2; 667 mtx_lock(sema_mtxp); 668 if ((error = semvalid(uap->semid, semakptr)) != 0) 669 goto done2; 670 if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_R))) 671 goto done2; 672 sbuf = semakptr->u; 673 mtx_unlock(sema_mtxp); 674 error = copyout(&semakptr->u, real_arg.buf, 675 sizeof(struct semid_ds)); 676 break; 677 678 case GETNCNT: 679 mtx_lock(sema_mtxp); 680 if ((error = semvalid(uap->semid, semakptr)) != 0) 681 goto done2; 682 if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_R))) 683 goto done2; 684 if (semnum < 0 || semnum >= semakptr->u.sem_nsems) { 685 error = EINVAL; 686 goto done2; 687 } 688 rval = semakptr->u.sem_base[semnum].semncnt; 689 break; 690 691 case GETPID: 692 mtx_lock(sema_mtxp); 693 if ((error = semvalid(uap->semid, semakptr)) != 0) 694 goto done2; 695 if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_R))) 696 goto done2; 697 if (semnum < 0 || semnum >= semakptr->u.sem_nsems) { 698 error = EINVAL; 699 goto done2; 700 } 701 rval = semakptr->u.sem_base[semnum].sempid; 702 break; 703 704 case GETVAL: 705 mtx_lock(sema_mtxp); 706 if ((error = semvalid(uap->semid, semakptr)) != 0) 707 goto done2; 708 if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_R))) 709 goto done2; 710 if (semnum < 0 || semnum >= semakptr->u.sem_nsems) { 711 error = EINVAL; 712 goto done2; 713 } 714 rval = semakptr->u.sem_base[semnum].semval; 715 break; 716 717 case GETALL: 718 if ((error = copyin(arg, &real_arg, sizeof(real_arg))) != 0) 719 goto done2; 720 array = malloc(sizeof(*array) * semakptr->u.sem_nsems, M_TEMP, 721 M_WAITOK); 722 mtx_lock(sema_mtxp); 723 if ((error = semvalid(uap->semid, semakptr)) != 0) 724 goto done2; 725 if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_R))) 726 goto done2; 727 for (i = 0; i < semakptr->u.sem_nsems; i++) 728 array[i] = semakptr->u.sem_base[i].semval; 729 mtx_unlock(sema_mtxp); 730 error = copyout(array, real_arg.array, 731 i * sizeof(real_arg.array[0])); 732 break; 733 734 case GETZCNT: 735 mtx_lock(sema_mtxp); 736 if ((error = semvalid(uap->semid, semakptr)) != 0) 737 goto done2; 738 if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_R))) 739 goto done2; 740 if (semnum < 0 || semnum >= semakptr->u.sem_nsems) { 741 error = EINVAL; 742 goto done2; 743 } 744 rval = semakptr->u.sem_base[semnum].semzcnt; 745 break; 746 747 case SETVAL: 748 if ((error = copyin(arg, &real_arg, sizeof(real_arg))) != 0) 749 goto done2; 750 mtx_lock(sema_mtxp); 751 if ((error = semvalid(uap->semid, semakptr)) != 0) 752 goto done2; 753 if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_W))) 754 goto done2; 755 if (semnum < 0 || semnum >= semakptr->u.sem_nsems) { 756 error = EINVAL; 757 goto done2; 758 } 759 if (real_arg.val < 0 || real_arg.val > seminfo.semvmx) { 760 error = ERANGE; 761 goto done2; 762 } 763 semakptr->u.sem_base[semnum].semval = real_arg.val; 764 SEMUNDO_LOCK(); 765 semundo_clear(semid, semnum); 766 SEMUNDO_UNLOCK(); 767 wakeup(semakptr); 768 break; 769 770 case SETALL: 771 mtx_lock(sema_mtxp); 772 raced: 773 if ((error = semvalid(uap->semid, semakptr)) != 0) 774 goto done2; 775 count = semakptr->u.sem_nsems; 776 mtx_unlock(sema_mtxp); 777 if ((error = copyin(arg, &real_arg, sizeof(real_arg))) != 0) 778 goto done2; 779 array = malloc(sizeof(*array) * count, M_TEMP, M_WAITOK); 780 copyin(real_arg.array, array, count * sizeof(*array)); 781 if (error) 782 break; 783 mtx_lock(sema_mtxp); 784 if ((error = semvalid(uap->semid, semakptr)) != 0) 785 goto done2; 786 /* we could have raced? */ 787 if (count != semakptr->u.sem_nsems) { 788 free(array, M_TEMP); 789 array = NULL; 790 goto raced; 791 } 792 if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_W))) 793 goto done2; 794 for (i = 0; i < semakptr->u.sem_nsems; i++) { 795 usval = array[i]; 796 if (usval > seminfo.semvmx) { 797 error = ERANGE; 798 break; 799 } 800 semakptr->u.sem_base[i].semval = usval; 801 } 802 SEMUNDO_LOCK(); 803 semundo_clear(semid, -1); 804 SEMUNDO_UNLOCK(); 805 wakeup(semakptr); 806 break; 807 808 default: 809 error = EINVAL; 810 break; 811 } 812 813 if (error == 0) 814 td->td_retval[0] = rval; 815 done2: 816 if (mtx_owned(sema_mtxp)) 817 mtx_unlock(sema_mtxp); 818 if (array != NULL) 819 free(array, M_TEMP); 820 return(error); 821 } 822 823 #ifndef _SYS_SYSPROTO_H_ 824 struct semget_args { 825 key_t key; 826 int nsems; 827 int semflg; 828 }; 829 #endif 830 831 /* 832 * MPSAFE 833 */ 834 int 835 semget(td, uap) 836 struct thread *td; 837 struct semget_args *uap; 838 { 839 int semid, error = 0; 840 int key = uap->key; 841 int nsems = uap->nsems; 842 int semflg = uap->semflg; 843 struct ucred *cred = td->td_ucred; 844 845 DPRINTF(("semget(0x%x, %d, 0%o)\n", key, nsems, semflg)); 846 if (!jail_sysvipc_allowed && jailed(td->td_ucred)) 847 return (ENOSYS); 848 849 mtx_lock(&Giant); 850 if (key != IPC_PRIVATE) { 851 for (semid = 0; semid < seminfo.semmni; semid++) { 852 if ((sema[semid].u.sem_perm.mode & SEM_ALLOC) && 853 sema[semid].u.sem_perm.key == key) 854 break; 855 } 856 if (semid < seminfo.semmni) { 857 DPRINTF(("found public key\n")); 858 if ((error = ipcperm(td, &sema[semid].u.sem_perm, 859 semflg & 0700))) { 860 goto done2; 861 } 862 if (nsems > 0 && sema[semid].u.sem_nsems < nsems) { 863 DPRINTF(("too small\n")); 864 error = EINVAL; 865 goto done2; 866 } 867 if ((semflg & IPC_CREAT) && (semflg & IPC_EXCL)) { 868 DPRINTF(("not exclusive\n")); 869 error = EEXIST; 870 goto done2; 871 } 872 #ifdef MAC 873 error = mac_check_sysv_semget(cred, &sema[semid]); 874 if (error != 0) { 875 MPRINTF(("mac_check_sysv_semget returned %d\n", 876 error)); 877 goto done2; 878 } 879 #endif 880 goto found; 881 } 882 } 883 884 DPRINTF(("need to allocate the semid_kernel\n")); 885 if (key == IPC_PRIVATE || (semflg & IPC_CREAT)) { 886 if (nsems <= 0 || nsems > seminfo.semmsl) { 887 DPRINTF(("nsems out of range (0<%d<=%d)\n", nsems, 888 seminfo.semmsl)); 889 error = EINVAL; 890 goto done2; 891 } 892 if (nsems > seminfo.semmns - semtot) { 893 DPRINTF(( 894 "not enough semaphores left (need %d, got %d)\n", 895 nsems, seminfo.semmns - semtot)); 896 error = ENOSPC; 897 goto done2; 898 } 899 for (semid = 0; semid < seminfo.semmni; semid++) { 900 if ((sema[semid].u.sem_perm.mode & SEM_ALLOC) == 0) 901 break; 902 } 903 if (semid == seminfo.semmni) { 904 DPRINTF(("no more semid_kernel's available\n")); 905 error = ENOSPC; 906 goto done2; 907 } 908 DPRINTF(("semid %d is available\n", semid)); 909 sema[semid].u.sem_perm.key = key; 910 sema[semid].u.sem_perm.cuid = cred->cr_uid; 911 sema[semid].u.sem_perm.uid = cred->cr_uid; 912 sema[semid].u.sem_perm.cgid = cred->cr_gid; 913 sema[semid].u.sem_perm.gid = cred->cr_gid; 914 sema[semid].u.sem_perm.mode = (semflg & 0777) | SEM_ALLOC; 915 sema[semid].u.sem_perm.seq = 916 (sema[semid].u.sem_perm.seq + 1) & 0x7fff; 917 sema[semid].u.sem_nsems = nsems; 918 sema[semid].u.sem_otime = 0; 919 sema[semid].u.sem_ctime = time_second; 920 sema[semid].u.sem_base = &sem[semtot]; 921 semtot += nsems; 922 bzero(sema[semid].u.sem_base, 923 sizeof(sema[semid].u.sem_base[0])*nsems); 924 #ifdef MAC 925 mac_create_sysv_sema(cred, &sema[semid]); 926 #endif 927 DPRINTF(("sembase = 0x%x, next = 0x%x\n", 928 sema[semid].u.sem_base, &sem[semtot])); 929 } else { 930 DPRINTF(("didn't find it and wasn't asked to create it\n")); 931 error = ENOENT; 932 goto done2; 933 } 934 935 found: 936 td->td_retval[0] = IXSEQ_TO_IPCID(semid, sema[semid].u.sem_perm); 937 done2: 938 mtx_unlock(&Giant); 939 return (error); 940 } 941 942 #ifndef _SYS_SYSPROTO_H_ 943 struct semop_args { 944 int semid; 945 struct sembuf *sops; 946 size_t nsops; 947 }; 948 #endif 949 950 /* 951 * MPSAFE 952 */ 953 int 954 semop(td, uap) 955 struct thread *td; 956 struct semop_args *uap; 957 { 958 #define SMALL_SOPS 8 959 struct sembuf small_sops[SMALL_SOPS]; 960 int semid = uap->semid; 961 size_t nsops = uap->nsops; 962 struct sembuf *sops; 963 struct semid_kernel *semakptr; 964 struct sembuf *sopptr = 0; 965 struct sem *semptr = 0; 966 struct sem_undo *suptr; 967 struct mtx *sema_mtxp; 968 size_t i, j, k; 969 int error; 970 int do_wakeup, do_undos; 971 972 DPRINTF(("call to semop(%d, 0x%x, %u)\n", semid, sops, nsops)); 973 974 if (!jail_sysvipc_allowed && jailed(td->td_ucred)) 975 return (ENOSYS); 976 977 semid = IPCID_TO_IX(semid); /* Convert back to zero origin */ 978 979 if (semid < 0 || semid >= seminfo.semmni) 980 return (EINVAL); 981 982 /* Allocate memory for sem_ops */ 983 if (nsops <= SMALL_SOPS) 984 sops = small_sops; 985 else if (nsops <= seminfo.semopm) 986 sops = malloc(nsops * sizeof(*sops), M_TEMP, M_WAITOK); 987 else { 988 DPRINTF(("too many sops (max=%d, nsops=%d)\n", seminfo.semopm, 989 nsops)); 990 return (E2BIG); 991 } 992 if ((error = copyin(uap->sops, sops, nsops * sizeof(sops[0]))) != 0) { 993 DPRINTF(("error = %d from copyin(%08x, %08x, %d)\n", error, 994 uap->sops, sops, nsops * sizeof(sops[0]))); 995 if (sops != small_sops) 996 free(sops, M_SEM); 997 return (error); 998 } 999 1000 semakptr = &sema[semid]; 1001 sema_mtxp = &sema_mtx[semid]; 1002 mtx_lock(sema_mtxp); 1003 if ((semakptr->u.sem_perm.mode & SEM_ALLOC) == 0) { 1004 error = EINVAL; 1005 goto done2; 1006 } 1007 if (semakptr->u.sem_perm.seq != IPCID_TO_SEQ(uap->semid)) { 1008 error = EINVAL; 1009 goto done2; 1010 } 1011 /* 1012 * Initial pass thru sops to see what permissions are needed. 1013 * Also perform any checks that don't need repeating on each 1014 * attempt to satisfy the request vector. 1015 */ 1016 j = 0; /* permission needed */ 1017 do_undos = 0; 1018 for (i = 0; i < nsops; i++) { 1019 sopptr = &sops[i]; 1020 if (sopptr->sem_num >= semakptr->u.sem_nsems) { 1021 error = EFBIG; 1022 goto done2; 1023 } 1024 if (sopptr->sem_flg & SEM_UNDO && sopptr->sem_op != 0) 1025 do_undos = 1; 1026 j |= (sopptr->sem_op == 0) ? SEM_R : SEM_A; 1027 } 1028 1029 if ((error = ipcperm(td, &semakptr->u.sem_perm, j))) { 1030 DPRINTF(("error = %d from ipaccess\n", error)); 1031 goto done2; 1032 } 1033 #ifdef MAC 1034 error = mac_check_sysv_semop(td->td_ucred, semakptr, j); 1035 if (error != 0) { 1036 MPRINTF(("mac_check_sysv_semop returned %d\n", error)); 1037 goto done2; 1038 } 1039 #endif 1040 1041 /* 1042 * Loop trying to satisfy the vector of requests. 1043 * If we reach a point where we must wait, any requests already 1044 * performed are rolled back and we go to sleep until some other 1045 * process wakes us up. At this point, we start all over again. 1046 * 1047 * This ensures that from the perspective of other tasks, a set 1048 * of requests is atomic (never partially satisfied). 1049 */ 1050 for (;;) { 1051 do_wakeup = 0; 1052 error = 0; /* error return if necessary */ 1053 1054 for (i = 0; i < nsops; i++) { 1055 sopptr = &sops[i]; 1056 semptr = &semakptr->u.sem_base[sopptr->sem_num]; 1057 1058 DPRINTF(( 1059 "semop: semakptr=%x, sem_base=%x, " 1060 "semptr=%x, sem[%d]=%d : op=%d, flag=%s\n", 1061 semakptr, semakptr->u.sem_base, semptr, 1062 sopptr->sem_num, semptr->semval, sopptr->sem_op, 1063 (sopptr->sem_flg & IPC_NOWAIT) ? 1064 "nowait" : "wait")); 1065 1066 if (sopptr->sem_op < 0) { 1067 if (semptr->semval + sopptr->sem_op < 0) { 1068 DPRINTF(("semop: can't do it now\n")); 1069 break; 1070 } else { 1071 semptr->semval += sopptr->sem_op; 1072 if (semptr->semval == 0 && 1073 semptr->semzcnt > 0) 1074 do_wakeup = 1; 1075 } 1076 } else if (sopptr->sem_op == 0) { 1077 if (semptr->semval != 0) { 1078 DPRINTF(("semop: not zero now\n")); 1079 break; 1080 } 1081 } else if (semptr->semval + sopptr->sem_op > 1082 seminfo.semvmx) { 1083 error = ERANGE; 1084 break; 1085 } else { 1086 if (semptr->semncnt > 0) 1087 do_wakeup = 1; 1088 semptr->semval += sopptr->sem_op; 1089 } 1090 } 1091 1092 /* 1093 * Did we get through the entire vector? 1094 */ 1095 if (i >= nsops) 1096 goto done; 1097 1098 /* 1099 * No ... rollback anything that we've already done 1100 */ 1101 DPRINTF(("semop: rollback 0 through %d\n", i-1)); 1102 for (j = 0; j < i; j++) 1103 semakptr->u.sem_base[sops[j].sem_num].semval -= 1104 sops[j].sem_op; 1105 1106 /* If we detected an error, return it */ 1107 if (error != 0) 1108 goto done2; 1109 1110 /* 1111 * If the request that we couldn't satisfy has the 1112 * NOWAIT flag set then return with EAGAIN. 1113 */ 1114 if (sopptr->sem_flg & IPC_NOWAIT) { 1115 error = EAGAIN; 1116 goto done2; 1117 } 1118 1119 if (sopptr->sem_op == 0) 1120 semptr->semzcnt++; 1121 else 1122 semptr->semncnt++; 1123 1124 DPRINTF(("semop: good night!\n")); 1125 error = msleep(semakptr, sema_mtxp, (PZERO - 4) | PCATCH, 1126 "semwait", 0); 1127 DPRINTF(("semop: good morning (error=%d)!\n", error)); 1128 /* return code is checked below, after sem[nz]cnt-- */ 1129 1130 /* 1131 * Make sure that the semaphore still exists 1132 */ 1133 if ((semakptr->u.sem_perm.mode & SEM_ALLOC) == 0 || 1134 semakptr->u.sem_perm.seq != IPCID_TO_SEQ(uap->semid)) { 1135 error = EIDRM; 1136 goto done2; 1137 } 1138 1139 /* 1140 * The semaphore is still alive. Readjust the count of 1141 * waiting processes. 1142 */ 1143 if (sopptr->sem_op == 0) 1144 semptr->semzcnt--; 1145 else 1146 semptr->semncnt--; 1147 1148 /* 1149 * Is it really morning, or was our sleep interrupted? 1150 * (Delayed check of msleep() return code because we 1151 * need to decrement sem[nz]cnt either way.) 1152 */ 1153 if (error != 0) { 1154 error = EINTR; 1155 goto done2; 1156 } 1157 DPRINTF(("semop: good morning!\n")); 1158 } 1159 1160 done: 1161 /* 1162 * Process any SEM_UNDO requests. 1163 */ 1164 if (do_undos) { 1165 SEMUNDO_LOCK(); 1166 suptr = NULL; 1167 for (i = 0; i < nsops; i++) { 1168 /* 1169 * We only need to deal with SEM_UNDO's for non-zero 1170 * op's. 1171 */ 1172 int adjval; 1173 1174 if ((sops[i].sem_flg & SEM_UNDO) == 0) 1175 continue; 1176 adjval = sops[i].sem_op; 1177 if (adjval == 0) 1178 continue; 1179 error = semundo_adjust(td, &suptr, semid, 1180 sops[i].sem_num, -adjval); 1181 if (error == 0) 1182 continue; 1183 1184 /* 1185 * Oh-Oh! We ran out of either sem_undo's or undo's. 1186 * Rollback the adjustments to this point and then 1187 * rollback the semaphore ups and down so we can return 1188 * with an error with all structures restored. We 1189 * rollback the undo's in the exact reverse order that 1190 * we applied them. This guarantees that we won't run 1191 * out of space as we roll things back out. 1192 */ 1193 for (j = 0; j < i; j++) { 1194 k = i - j - 1; 1195 if ((sops[k].sem_flg & SEM_UNDO) == 0) 1196 continue; 1197 adjval = sops[k].sem_op; 1198 if (adjval == 0) 1199 continue; 1200 if (semundo_adjust(td, &suptr, semid, 1201 sops[k].sem_num, adjval) != 0) 1202 panic("semop - can't undo undos"); 1203 } 1204 1205 for (j = 0; j < nsops; j++) 1206 semakptr->u.sem_base[sops[j].sem_num].semval -= 1207 sops[j].sem_op; 1208 1209 DPRINTF(("error = %d from semundo_adjust\n", error)); 1210 SEMUNDO_UNLOCK(); 1211 goto done2; 1212 } /* loop through the sops */ 1213 SEMUNDO_UNLOCK(); 1214 } /* if (do_undos) */ 1215 1216 /* We're definitely done - set the sempid's and time */ 1217 for (i = 0; i < nsops; i++) { 1218 sopptr = &sops[i]; 1219 semptr = &semakptr->u.sem_base[sopptr->sem_num]; 1220 semptr->sempid = td->td_proc->p_pid; 1221 } 1222 semakptr->u.sem_otime = time_second; 1223 1224 /* 1225 * Do a wakeup if any semaphore was up'd whilst something was 1226 * sleeping on it. 1227 */ 1228 if (do_wakeup) { 1229 DPRINTF(("semop: doing wakeup\n")); 1230 wakeup(semakptr); 1231 DPRINTF(("semop: back from wakeup\n")); 1232 } 1233 DPRINTF(("semop: done\n")); 1234 td->td_retval[0] = 0; 1235 done2: 1236 mtx_unlock(sema_mtxp); 1237 if (sops != small_sops) 1238 free(sops, M_SEM); 1239 return (error); 1240 } 1241 1242 /* 1243 * Go through the undo structures for this process and apply the adjustments to 1244 * semaphores. 1245 */ 1246 static void 1247 semexit_myhook(arg, p) 1248 void *arg; 1249 struct proc *p; 1250 { 1251 struct sem_undo *suptr; 1252 struct sem_undo **supptr; 1253 1254 /* 1255 * Go through the chain of undo vectors looking for one 1256 * associated with this process. 1257 */ 1258 SEMUNDO_LOCK(); 1259 SLIST_FOREACH_PREVPTR(suptr, supptr, &semu_list, un_next) { 1260 if (suptr->un_proc == p) 1261 break; 1262 } 1263 SEMUNDO_UNLOCK(); 1264 1265 if (suptr == NULL) 1266 return; 1267 1268 DPRINTF(("proc @%08x has undo structure with %d entries\n", p, 1269 suptr->un_cnt)); 1270 1271 /* 1272 * If there are any active undo elements then process them. 1273 */ 1274 if (suptr->un_cnt > 0) { 1275 int ix; 1276 1277 for (ix = 0; ix < suptr->un_cnt; ix++) { 1278 int semid = suptr->un_ent[ix].un_id; 1279 int semnum = suptr->un_ent[ix].un_num; 1280 int adjval = suptr->un_ent[ix].un_adjval; 1281 struct semid_kernel *semakptr; 1282 struct mtx *sema_mtxp; 1283 1284 semakptr = &sema[semid]; 1285 sema_mtxp = &sema_mtx[semid]; 1286 mtx_lock(sema_mtxp); 1287 SEMUNDO_LOCK(); 1288 if ((semakptr->u.sem_perm.mode & SEM_ALLOC) == 0) 1289 panic("semexit - semid not allocated"); 1290 if (semnum >= semakptr->u.sem_nsems) 1291 panic("semexit - semnum out of range"); 1292 1293 DPRINTF(( 1294 "semexit: %08x id=%d num=%d(adj=%d) ; sem=%d\n", 1295 suptr->un_proc, suptr->un_ent[ix].un_id, 1296 suptr->un_ent[ix].un_num, 1297 suptr->un_ent[ix].un_adjval, 1298 semakptr->u.sem_base[semnum].semval)); 1299 1300 if (adjval < 0) { 1301 if (semakptr->u.sem_base[semnum].semval < 1302 -adjval) 1303 semakptr->u.sem_base[semnum].semval = 0; 1304 else 1305 semakptr->u.sem_base[semnum].semval += 1306 adjval; 1307 } else 1308 semakptr->u.sem_base[semnum].semval += adjval; 1309 1310 wakeup(semakptr); 1311 DPRINTF(("semexit: back from wakeup\n")); 1312 mtx_unlock(sema_mtxp); 1313 SEMUNDO_UNLOCK(); 1314 } 1315 } 1316 1317 /* 1318 * Deallocate the undo vector. 1319 */ 1320 DPRINTF(("removing vector\n")); 1321 suptr->un_proc = NULL; 1322 *supptr = SLIST_NEXT(suptr, un_next); 1323 } 1324 1325 static int 1326 sysctl_sema(SYSCTL_HANDLER_ARGS) 1327 { 1328 1329 return (SYSCTL_OUT(req, sema, 1330 sizeof(struct semid_kernel) * seminfo.semmni)); 1331 } 1332