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Ignore machine-check MSRs
[freebsd-src/fkvm-freebsd.git] / sys / kern / sysv_sem.c
blob80d07ba8dc38ffb4904bd7d0ad311e16ef9b22d1
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/syscallsubr.h>
57 #include <sys/sysent.h>
58 #include <sys/sysctl.h>
59 #include <sys/uio.h>
60 #include <sys/malloc.h>
61 #include <sys/jail.h>
62
63 #include <security/mac/mac_framework.h>
64
65 static MALLOC_DEFINE(M_SEM, "sem", "SVID compatible semaphores");
66
67 #ifdef SEM_DEBUG
68 #define DPRINTF(a) printf a
69 #else
70 #define DPRINTF(a)
71 #endif
72
73 static void seminit(void);
74 static int sysvsem_modload(struct module *, int, void *);
75 static int semunload(void);
76 static void semexit_myhook(void *arg, struct proc *p);
77 static int sysctl_sema(SYSCTL_HANDLER_ARGS);
78 static int semvalid(int semid, struct semid_kernel *semakptr);
79
80 #ifndef _SYS_SYSPROTO_H_
81 struct __semctl_args;
82 int __semctl(struct thread *td, struct __semctl_args *uap);
83 struct semget_args;
84 int semget(struct thread *td, struct semget_args *uap);
85 struct semop_args;
86 int semop(struct thread *td, struct semop_args *uap);
87 #endif
88
89 static struct sem_undo *semu_alloc(struct thread *td);
90 static int semundo_adjust(struct thread *td, struct sem_undo **supptr,
91 int semid, int semnum, int adjval);
92 static void semundo_clear(int semid, int semnum);
93
94 /* XXX casting to (sy_call_t *) is bogus, as usual. */
95 static sy_call_t *semcalls[] = {
96 (sy_call_t *)__semctl, (sy_call_t *)semget,
97 (sy_call_t *)semop
98 };
99
100 static struct mtx sem_mtx; /* semaphore global lock */
101 static int semtot = 0;
102 static struct semid_kernel *sema; /* semaphore id pool */
103 static struct mtx *sema_mtx; /* semaphore id pool mutexes*/
104 static struct sem *sem; /* semaphore pool */
105 SLIST_HEAD(, sem_undo) semu_list; /* list of active undo structures */
106 static int *semu; /* undo structure pool */
107 static eventhandler_tag semexit_tag;
108
109 #define SEMUNDO_MTX sem_mtx
110 #define SEMUNDO_LOCK() mtx_lock(&SEMUNDO_MTX);
111 #define SEMUNDO_UNLOCK() mtx_unlock(&SEMUNDO_MTX);
112 #define SEMUNDO_LOCKASSERT(how) mtx_assert(&SEMUNDO_MTX, (how));
113
114 struct sem {
115 u_short semval; /* semaphore value */
116 pid_t sempid; /* pid of last operation */
117 u_short semncnt; /* # awaiting semval > cval */
118 u_short semzcnt; /* # awaiting semval = 0 */
119 };
120
121 /*
122 * Undo structure (one per process)
123 */
124 struct sem_undo {
125 SLIST_ENTRY(sem_undo) un_next; /* ptr to next active undo structure */
126 struct proc *un_proc; /* owner of this structure */
127 short un_cnt; /* # of active entries */
128 struct undo {
129 short un_adjval; /* adjust on exit values */
130 short un_num; /* semaphore # */
131 int un_id; /* semid */
132 } un_ent[1]; /* undo entries */
133 };
134
135 /*
136 * Configuration parameters
137 */
138 #ifndef SEMMNI
139 #define SEMMNI 10 /* # of semaphore identifiers */
140 #endif
141 #ifndef SEMMNS
142 #define SEMMNS 60 /* # of semaphores in system */
143 #endif
144 #ifndef SEMUME
145 #define SEMUME 10 /* max # of undo entries per process */
146 #endif
147 #ifndef SEMMNU
148 #define SEMMNU 30 /* # of undo structures in system */
149 #endif
150
151 /* shouldn't need tuning */
152 #ifndef SEMMAP
153 #define SEMMAP 30 /* # of entries in semaphore map */
154 #endif
155 #ifndef SEMMSL
156 #define SEMMSL SEMMNS /* max # of semaphores per id */
157 #endif
158 #ifndef SEMOPM
159 #define SEMOPM 100 /* max # of operations per semop call */
160 #endif
161
162 #define SEMVMX 32767 /* semaphore maximum value */
163 #define SEMAEM 16384 /* adjust on exit max value */
164
165 /*
166 * Due to the way semaphore memory is allocated, we have to ensure that
167 * SEMUSZ is properly aligned.
168 */
169
170 #define SEM_ALIGN(bytes) (((bytes) + (sizeof(long) - 1)) & ~(sizeof(long) - 1))
171
172 /* actual size of an undo structure */
173 #define SEMUSZ SEM_ALIGN(offsetof(struct sem_undo, un_ent[SEMUME]))
174
175 /*
176 * Macro to find a particular sem_undo vector
177 */
178 #define SEMU(ix) \
179 ((struct sem_undo *)(((intptr_t)semu)+ix * seminfo.semusz))
180
181 /*
182 * semaphore info struct
183 */
184 struct seminfo seminfo = {
185 SEMMAP, /* # of entries in semaphore map */
186 SEMMNI, /* # of semaphore identifiers */
187 SEMMNS, /* # of semaphores in system */
188 SEMMNU, /* # of undo structures in system */
189 SEMMSL, /* max # of semaphores per id */
190 SEMOPM, /* max # of operations per semop call */
191 SEMUME, /* max # of undo entries per process */
192 SEMUSZ, /* size in bytes of undo structure */
193 SEMVMX, /* semaphore maximum value */
194 SEMAEM /* adjust on exit max value */
195 };
196
197 SYSCTL_INT(_kern_ipc, OID_AUTO, semmap, CTLFLAG_RW, &seminfo.semmap, 0,
198 "Number of entries in the semaphore map");
199 SYSCTL_INT(_kern_ipc, OID_AUTO, semmni, CTLFLAG_RDTUN, &seminfo.semmni, 0,
200 "Number of semaphore identifiers");
201 SYSCTL_INT(_kern_ipc, OID_AUTO, semmns, CTLFLAG_RDTUN, &seminfo.semmns, 0,
202 "Maximum number of semaphores in the system");
203 SYSCTL_INT(_kern_ipc, OID_AUTO, semmnu, CTLFLAG_RDTUN, &seminfo.semmnu, 0,
204 "Maximum number of undo structures in the system");
205 SYSCTL_INT(_kern_ipc, OID_AUTO, semmsl, CTLFLAG_RW, &seminfo.semmsl, 0,
206 "Max semaphores per id");
207 SYSCTL_INT(_kern_ipc, OID_AUTO, semopm, CTLFLAG_RDTUN, &seminfo.semopm, 0,
208 "Max operations per semop call");
209 SYSCTL_INT(_kern_ipc, OID_AUTO, semume, CTLFLAG_RDTUN, &seminfo.semume, 0,
210 "Max undo entries per process");
211 SYSCTL_INT(_kern_ipc, OID_AUTO, semusz, CTLFLAG_RDTUN, &seminfo.semusz, 0,
212 "Size in bytes of undo structure");
213 SYSCTL_INT(_kern_ipc, OID_AUTO, semvmx, CTLFLAG_RW, &seminfo.semvmx, 0,
214 "Semaphore maximum value");
215 SYSCTL_INT(_kern_ipc, OID_AUTO, semaem, CTLFLAG_RW, &seminfo.semaem, 0,
216 "Adjust on exit max value");
217 SYSCTL_PROC(_kern_ipc, OID_AUTO, sema, CTLFLAG_RD,
218 NULL, 0, sysctl_sema, "", "");
219
220 static void
221 seminit(void)
222 {
223 int i;
224
225 TUNABLE_INT_FETCH("kern.ipc.semmap", &seminfo.semmap);
226 TUNABLE_INT_FETCH("kern.ipc.semmni", &seminfo.semmni);
227 TUNABLE_INT_FETCH("kern.ipc.semmns", &seminfo.semmns);
228 TUNABLE_INT_FETCH("kern.ipc.semmnu", &seminfo.semmnu);
229 TUNABLE_INT_FETCH("kern.ipc.semmsl", &seminfo.semmsl);
230 TUNABLE_INT_FETCH("kern.ipc.semopm", &seminfo.semopm);
231 TUNABLE_INT_FETCH("kern.ipc.semume", &seminfo.semume);
232 TUNABLE_INT_FETCH("kern.ipc.semusz", &seminfo.semusz);
233 TUNABLE_INT_FETCH("kern.ipc.semvmx", &seminfo.semvmx);
234 TUNABLE_INT_FETCH("kern.ipc.semaem", &seminfo.semaem);
235
236 sem = malloc(sizeof(struct sem) * seminfo.semmns, M_SEM, M_WAITOK);
237 sema = malloc(sizeof(struct semid_kernel) * seminfo.semmni, M_SEM,
238 M_WAITOK);
239 sema_mtx = malloc(sizeof(struct mtx) * seminfo.semmni, M_SEM,
240 M_WAITOK | M_ZERO);
241 semu = malloc(seminfo.semmnu * seminfo.semusz, M_SEM, M_WAITOK);
242
243 for (i = 0; i < seminfo.semmni; i++) {
244 sema[i].u.sem_base = 0;
245 sema[i].u.sem_perm.mode = 0;
246 sema[i].u.sem_perm.seq = 0;
247 #ifdef MAC
248 mac_sysvsem_init(&sema[i]);
249 #endif
250 }
251 for (i = 0; i < seminfo.semmni; i++)
252 mtx_init(&sema_mtx[i], "semid", NULL, MTX_DEF);
253 for (i = 0; i < seminfo.semmnu; i++) {
254 struct sem_undo *suptr = SEMU(i);
255 suptr->un_proc = NULL;
256 }
257 SLIST_INIT(&semu_list);
258 mtx_init(&sem_mtx, "sem", NULL, MTX_DEF);
259 semexit_tag = EVENTHANDLER_REGISTER(process_exit, semexit_myhook, NULL,
260 EVENTHANDLER_PRI_ANY);
261 }
262
263 static int
264 semunload(void)
265 {
266 int i;
267
268 if (semtot != 0)
269 return (EBUSY);
270
271 EVENTHANDLER_DEREGISTER(process_exit, semexit_tag);
272 #ifdef MAC
273 for (i = 0; i < seminfo.semmni; i++)
274 mac_sysvsem_destroy(&sema[i]);
275 #endif
276 free(sem, M_SEM);
277 free(sema, M_SEM);
278 free(semu, M_SEM);
279 for (i = 0; i < seminfo.semmni; i++)
280 mtx_destroy(&sema_mtx[i]);
281 mtx_destroy(&sem_mtx);
282 return (0);
283 }
284
285 static int
286 sysvsem_modload(struct module *module, int cmd, void *arg)
287 {
288 int error = 0;
289
290 switch (cmd) {
291 case MOD_LOAD:
292 seminit();
293 break;
294 case MOD_UNLOAD:
295 error = semunload();
296 break;
297 case MOD_SHUTDOWN:
298 break;
299 default:
300 error = EINVAL;
301 break;
302 }
303 return (error);
304 }
305
306 static moduledata_t sysvsem_mod = {
307 "sysvsem",
308 &sysvsem_modload,
309 NULL
310 };
311
312 SYSCALL_MODULE_HELPER(semsys);
313 SYSCALL_MODULE_HELPER(__semctl);
314 SYSCALL_MODULE_HELPER(semget);
315 SYSCALL_MODULE_HELPER(semop);
316
317 DECLARE_MODULE(sysvsem, sysvsem_mod,
318 SI_SUB_SYSV_SEM, SI_ORDER_FIRST);
319 MODULE_VERSION(sysvsem, 1);
320
321 /*
322 * Entry point for all SEM calls.
323 */
324 int
325 semsys(td, uap)
326 struct thread *td;
327 /* XXX actually varargs. */
328 struct semsys_args /* {
329 int which;
330 int a2;
331 int a3;
332 int a4;
333 int a5;
334 } */ *uap;
335 {
336 int error;
337
338 if (!jail_sysvipc_allowed && jailed(td->td_ucred))
339 return (ENOSYS);
340 if (uap->which < 0 ||
341 uap->which >= sizeof(semcalls)/sizeof(semcalls[0]))
342 return (EINVAL);
343 error = (*semcalls[uap->which])(td, &uap->a2);
344 return (error);
345 }
346
347 /*
348 * Allocate a new sem_undo structure for a process
349 * (returns ptr to structure or NULL if no more room)
350 */
351
352 static struct sem_undo *
353 semu_alloc(td)
354 struct thread *td;
355 {
356 int i;
357 struct sem_undo *suptr;
358 struct sem_undo **supptr;
359 int attempt;
360
361 SEMUNDO_LOCKASSERT(MA_OWNED);
362 /*
363 * Try twice to allocate something.
364 * (we'll purge an empty structure after the first pass so
365 * two passes are always enough)
366 */
367
368 for (attempt = 0; attempt < 2; attempt++) {
369 /*
370 * Look for a free structure.
371 * Fill it in and return it if we find one.
372 */
373
374 for (i = 0; i < seminfo.semmnu; i++) {
375 suptr = SEMU(i);
376 if (suptr->un_proc == NULL) {
377 SLIST_INSERT_HEAD(&semu_list, suptr, un_next);
378 suptr->un_cnt = 0;
379 suptr->un_proc = td->td_proc;
380 return(suptr);
381 }
382 }
383
384 /*
385 * We didn't find a free one, if this is the first attempt
386 * then try to free a structure.
387 */
388
389 if (attempt == 0) {
390 /* All the structures are in use - try to free one */
391 int did_something = 0;
392
393 SLIST_FOREACH_PREVPTR(suptr, supptr, &semu_list,
394 un_next) {
395 if (suptr->un_cnt == 0) {
396 suptr->un_proc = NULL;
397 did_something = 1;
398 *supptr = SLIST_NEXT(suptr, un_next);
399 break;
400 }
401 }
402
403 /* If we didn't free anything then just give-up */
404 if (!did_something)
405 return(NULL);
406 } else {
407 /*
408 * The second pass failed even though we freed
409 * something after the first pass!
410 * This is IMPOSSIBLE!
411 */
412 panic("semu_alloc - second attempt failed");
413 }
414 }
415 return (NULL);
416 }
417
418 /*
419 * Adjust a particular entry for a particular proc
420 */
421
422 static int
423 semundo_adjust(td, supptr, semid, semnum, adjval)
424 struct thread *td;
425 struct sem_undo **supptr;
426 int semid, semnum;
427 int adjval;
428 {
429 struct proc *p = td->td_proc;
430 struct sem_undo *suptr;
431 struct undo *sunptr;
432 int i;
433
434 SEMUNDO_LOCKASSERT(MA_OWNED);
435 /* Look for and remember the sem_undo if the caller doesn't provide
436 it */
437
438 suptr = *supptr;
439 if (suptr == NULL) {
440 SLIST_FOREACH(suptr, &semu_list, un_next) {
441 if (suptr->un_proc == p) {
442 *supptr = suptr;
443 break;
444 }
445 }
446 if (suptr == NULL) {
447 if (adjval == 0)
448 return(0);
449 suptr = semu_alloc(td);
450 if (suptr == NULL)
451 return(ENOSPC);
452 *supptr = suptr;
453 }
454 }
455
456 /*
457 * Look for the requested entry and adjust it (delete if adjval becomes
458 * 0).
459 */
460 sunptr = &suptr->un_ent[0];
461 for (i = 0; i < suptr->un_cnt; i++, sunptr++) {
462 if (sunptr->un_id != semid || sunptr->un_num != semnum)
463 continue;
464 if (adjval != 0) {
465 adjval += sunptr->un_adjval;
466 if (adjval > seminfo.semaem || adjval < -seminfo.semaem)
467 return (ERANGE);
468 }
469 sunptr->un_adjval = adjval;
470 if (sunptr->un_adjval == 0) {
471 suptr->un_cnt--;
472 if (i < suptr->un_cnt)
473 suptr->un_ent[i] =
474 suptr->un_ent[suptr->un_cnt];
475 }
476 return(0);
477 }
478
479 /* Didn't find the right entry - create it */
480 if (adjval == 0)
481 return(0);
482 if (adjval > seminfo.semaem || adjval < -seminfo.semaem)
483 return (ERANGE);
484 if (suptr->un_cnt != seminfo.semume) {
485 sunptr = &suptr->un_ent[suptr->un_cnt];
486 suptr->un_cnt++;
487 sunptr->un_adjval = adjval;
488 sunptr->un_id = semid; sunptr->un_num = semnum;
489 } else
490 return(EINVAL);
491 return(0);
492 }
493
494 static void
495 semundo_clear(semid, semnum)
496 int semid, semnum;
497 {
498 struct sem_undo *suptr;
499
500 SEMUNDO_LOCKASSERT(MA_OWNED);
501 SLIST_FOREACH(suptr, &semu_list, un_next) {
502 struct undo *sunptr = &suptr->un_ent[0];
503 int i = 0;
504
505 while (i < suptr->un_cnt) {
506 if (sunptr->un_id == semid) {
507 if (semnum == -1 || sunptr->un_num == semnum) {
508 suptr->un_cnt--;
509 if (i < suptr->un_cnt) {
510 suptr->un_ent[i] =
511 suptr->un_ent[suptr->un_cnt];
512 continue;
513 }
514 }
515 if (semnum != -1)
516 break;
517 }
518 i++, sunptr++;
519 }
520 }
521 }
522
523 static int
524 semvalid(semid, semakptr)
525 int semid;
526 struct semid_kernel *semakptr;
527 {
528
529 return ((semakptr->u.sem_perm.mode & SEM_ALLOC) == 0 ||
530 semakptr->u.sem_perm.seq != IPCID_TO_SEQ(semid) ? EINVAL : 0);
531 }
532
533 /*
534 * Note that the user-mode half of this passes a union, not a pointer.
535 */
536 #ifndef _SYS_SYSPROTO_H_
537 struct __semctl_args {
538 int semid;
539 int semnum;
540 int cmd;
541 union semun *arg;
542 };
543 #endif
544 int
545 __semctl(td, uap)
546 struct thread *td;
547 struct __semctl_args *uap;
548 {
549 struct semid_ds dsbuf;
550 union semun arg, semun;
551 register_t rval;
552 int error;
553
554 switch (uap->cmd) {
555 case SEM_STAT:
556 case IPC_SET:
557 case IPC_STAT:
558 case GETALL:
559 case SETVAL:
560 case SETALL:
561 error = copyin(uap->arg, &arg, sizeof(arg));
562 if (error)
563 return (error);
564 break;
565 }
566
567 switch (uap->cmd) {
568 case SEM_STAT:
569 case IPC_STAT:
570 semun.buf = &dsbuf;
571 break;
572 case IPC_SET:
573 error = copyin(arg.buf, &dsbuf, sizeof(dsbuf));
574 if (error)
575 return (error);
576 semun.buf = &dsbuf;
577 break;
578 case GETALL:
579 case SETALL:
580 semun.array = arg.array;
581 break;
582 case SETVAL:
583 semun.val = arg.val;
584 break;
585 }
586
587 error = kern_semctl(td, uap->semid, uap->semnum, uap->cmd, &semun,
588 &rval);
589 if (error)
590 return (error);
591
592 switch (uap->cmd) {
593 case SEM_STAT:
594 case IPC_STAT:
595 error = copyout(&dsbuf, arg.buf, sizeof(dsbuf));
596 break;
597 }
598
599 if (error == 0)
600 td->td_retval[0] = rval;
601 return (error);
602 }
603
604 int
605 kern_semctl(struct thread *td, int semid, int semnum, int cmd,
606 union semun *arg, register_t *rval)
607 {
608 u_short *array;
609 struct ucred *cred = td->td_ucred;
610 int i, error;
611 struct semid_ds *sbuf;
612 struct semid_kernel *semakptr;
613 struct mtx *sema_mtxp;
614 u_short usval, count;
615 int semidx;
616
617 DPRINTF(("call to semctl(%d, %d, %d, 0x%p)\n",
618 semid, semnum, cmd, arg));
619 if (!jail_sysvipc_allowed && jailed(td->td_ucred))
620 return (ENOSYS);
621
622 array = NULL;
623
624 switch(cmd) {
625 case SEM_STAT:
626 /*
627 * For this command we assume semid is an array index
628 * rather than an IPC id.
629 */
630 if (semid < 0 || semid >= seminfo.semmni)
631 return (EINVAL);
632 semakptr = &sema[semid];
633 sema_mtxp = &sema_mtx[semid];
634 mtx_lock(sema_mtxp);
635 if ((semakptr->u.sem_perm.mode & SEM_ALLOC) == 0) {
636 error = EINVAL;
637 goto done2;
638 }
639 if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_R)))
640 goto done2;
641 #ifdef MAC
642 error = mac_sysvsem_check_semctl(cred, semakptr, cmd);
643 if (error != 0)
644 goto done2;
645 #endif
646 bcopy(&semakptr->u, arg->buf, sizeof(struct semid_ds));
647 *rval = IXSEQ_TO_IPCID(semid, semakptr->u.sem_perm);
648 mtx_unlock(sema_mtxp);
649 return (0);
650 }
651
652 semidx = IPCID_TO_IX(semid);
653 if (semidx < 0 || semidx >= seminfo.semmni)
654 return (EINVAL);
655
656 semakptr = &sema[semidx];
657 sema_mtxp = &sema_mtx[semidx];
658 mtx_lock(sema_mtxp);
659 #ifdef MAC
660 error = mac_sysvsem_check_semctl(cred, semakptr, cmd);
661 if (error != 0)
662 goto done2;
663 #endif
664
665 error = 0;
666 *rval = 0;
667
668 switch (cmd) {
669 case IPC_RMID:
670 if ((error = semvalid(semid, semakptr)) != 0)
671 goto done2;
672 if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_M)))
673 goto done2;
674 semakptr->u.sem_perm.cuid = cred->cr_uid;
675 semakptr->u.sem_perm.uid = cred->cr_uid;
676 semtot -= semakptr->u.sem_nsems;
677 for (i = semakptr->u.sem_base - sem; i < semtot; i++)
678 sem[i] = sem[i + semakptr->u.sem_nsems];
679 for (i = 0; i < seminfo.semmni; i++) {
680 if ((sema[i].u.sem_perm.mode & SEM_ALLOC) &&
681 sema[i].u.sem_base > semakptr->u.sem_base)
682 sema[i].u.sem_base -= semakptr->u.sem_nsems;
683 }
684 semakptr->u.sem_perm.mode = 0;
685 #ifdef MAC
686 mac_sysvsem_cleanup(semakptr);
687 #endif
688 SEMUNDO_LOCK();
689 semundo_clear(semidx, -1);
690 SEMUNDO_UNLOCK();
691 wakeup(semakptr);
692 break;
693
694 case IPC_SET:
695 if ((error = semvalid(semid, semakptr)) != 0)
696 goto done2;
697 if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_M)))
698 goto done2;
699 sbuf = arg->buf;
700 semakptr->u.sem_perm.uid = sbuf->sem_perm.uid;
701 semakptr->u.sem_perm.gid = sbuf->sem_perm.gid;
702 semakptr->u.sem_perm.mode = (semakptr->u.sem_perm.mode &
703 ~0777) | (sbuf->sem_perm.mode & 0777);
704 semakptr->u.sem_ctime = time_second;
705 break;
706
707 case IPC_STAT:
708 if ((error = semvalid(semid, semakptr)) != 0)
709 goto done2;
710 if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_R)))
711 goto done2;
712 bcopy(&semakptr->u, arg->buf, sizeof(struct semid_ds));
713 break;
714
715 case GETNCNT:
716 if ((error = semvalid(semid, semakptr)) != 0)
717 goto done2;
718 if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_R)))
719 goto done2;
720 if (semnum < 0 || semnum >= semakptr->u.sem_nsems) {
721 error = EINVAL;
722 goto done2;
723 }
724 *rval = semakptr->u.sem_base[semnum].semncnt;
725 break;
726
727 case GETPID:
728 if ((error = semvalid(semid, semakptr)) != 0)
729 goto done2;
730 if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_R)))
731 goto done2;
732 if (semnum < 0 || semnum >= semakptr->u.sem_nsems) {
733 error = EINVAL;
734 goto done2;
735 }
736 *rval = semakptr->u.sem_base[semnum].sempid;
737 break;
738
739 case GETVAL:
740 if ((error = semvalid(semid, semakptr)) != 0)
741 goto done2;
742 if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_R)))
743 goto done2;
744 if (semnum < 0 || semnum >= semakptr->u.sem_nsems) {
745 error = EINVAL;
746 goto done2;
747 }
748 *rval = semakptr->u.sem_base[semnum].semval;
749 break;
750
751 case GETALL:
752 /*
753 * Unfortunately, callers of this function don't know
754 * in advance how many semaphores are in this set.
755 * While we could just allocate the maximum size array
756 * and pass the actual size back to the caller, that
757 * won't work for SETALL since we can't copyin() more
758 * data than the user specified as we may return a
759 * spurious EFAULT.
760 *
761 * Note that the number of semaphores in a set is
762 * fixed for the life of that set. The only way that
763 * the 'count' could change while are blocked in
764 * malloc() is if this semaphore set were destroyed
765 * and a new one created with the same index.
766 * However, semvalid() will catch that due to the
767 * sequence number unless exactly 0x8000 (or a
768 * multiple thereof) semaphore sets for the same index
769 * are created and destroyed while we are in malloc!
770 *
771 */
772 count = semakptr->u.sem_nsems;
773 mtx_unlock(sema_mtxp);
774 array = malloc(sizeof(*array) * count, M_TEMP, M_WAITOK);
775 mtx_lock(sema_mtxp);
776 if ((error = semvalid(semid, semakptr)) != 0)
777 goto done2;
778 KASSERT(count == semakptr->u.sem_nsems, ("nsems changed"));
779 if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_R)))
780 goto done2;
781 for (i = 0; i < semakptr->u.sem_nsems; i++)
782 array[i] = semakptr->u.sem_base[i].semval;
783 mtx_unlock(sema_mtxp);
784 error = copyout(array, arg->array, count * sizeof(*array));
785 mtx_lock(sema_mtxp);
786 break;
787
788 case GETZCNT:
789 if ((error = semvalid(semid, semakptr)) != 0)
790 goto done2;
791 if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_R)))
792 goto done2;
793 if (semnum < 0 || semnum >= semakptr->u.sem_nsems) {
794 error = EINVAL;
795 goto done2;
796 }
797 *rval = semakptr->u.sem_base[semnum].semzcnt;
798 break;
799
800 case SETVAL:
801 if ((error = semvalid(semid, semakptr)) != 0)
802 goto done2;
803 if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_W)))
804 goto done2;
805 if (semnum < 0 || semnum >= semakptr->u.sem_nsems) {
806 error = EINVAL;
807 goto done2;
808 }
809 if (arg->val < 0 || arg->val > seminfo.semvmx) {
810 error = ERANGE;
811 goto done2;
812 }
813 semakptr->u.sem_base[semnum].semval = arg->val;
814 SEMUNDO_LOCK();
815 semundo_clear(semidx, semnum);
816 SEMUNDO_UNLOCK();
817 wakeup(semakptr);
818 break;
819
820 case SETALL:
821 /*
822 * See comment on GETALL for why 'count' shouldn't change
823 * and why we require a userland buffer.
824 */
825 count = semakptr->u.sem_nsems;
826 mtx_unlock(sema_mtxp);
827 array = malloc(sizeof(*array) * count, M_TEMP, M_WAITOK);
828 error = copyin(arg->array, array, count * sizeof(*array));
829 mtx_lock(sema_mtxp);
830 if (error)
831 break;
832 if ((error = semvalid(semid, semakptr)) != 0)
833 goto done2;
834 KASSERT(count == semakptr->u.sem_nsems, ("nsems changed"));
835 if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_W)))
836 goto done2;
837 for (i = 0; i < semakptr->u.sem_nsems; i++) {
838 usval = array[i];
839 if (usval > seminfo.semvmx) {
840 error = ERANGE;
841 break;
842 }
843 semakptr->u.sem_base[i].semval = usval;
844 }
845 SEMUNDO_LOCK();
846 semundo_clear(semidx, -1);
847 SEMUNDO_UNLOCK();
848 wakeup(semakptr);
849 break;
850
851 default:
852 error = EINVAL;
853 break;
854 }
855
856 done2:
857 mtx_unlock(sema_mtxp);
858 if (array != NULL)
859 free(array, M_TEMP);
860 return(error);
861 }
862
863 #ifndef _SYS_SYSPROTO_H_
864 struct semget_args {
865 key_t key;
866 int nsems;
867 int semflg;
868 };
869 #endif
870 int
871 semget(td, uap)
872 struct thread *td;
873 struct semget_args *uap;
874 {
875 int semid, error = 0;
876 int key = uap->key;
877 int nsems = uap->nsems;
878 int semflg = uap->semflg;
879 struct ucred *cred = td->td_ucred;
880
881 DPRINTF(("semget(0x%x, %d, 0%o)\n", key, nsems, semflg));
882 if (!jail_sysvipc_allowed && jailed(td->td_ucred))
883 return (ENOSYS);
884
885 mtx_lock(&Giant);
886 if (key != IPC_PRIVATE) {
887 for (semid = 0; semid < seminfo.semmni; semid++) {
888 if ((sema[semid].u.sem_perm.mode & SEM_ALLOC) &&
889 sema[semid].u.sem_perm.key == key)
890 break;
891 }
892 if (semid < seminfo.semmni) {
893 DPRINTF(("found public key\n"));
894 if ((error = ipcperm(td, &sema[semid].u.sem_perm,
895 semflg & 0700))) {
896 goto done2;
897 }
898 if (nsems > 0 && sema[semid].u.sem_nsems < nsems) {
899 DPRINTF(("too small\n"));
900 error = EINVAL;
901 goto done2;
902 }
903 if ((semflg & IPC_CREAT) && (semflg & IPC_EXCL)) {
904 DPRINTF(("not exclusive\n"));
905 error = EEXIST;
906 goto done2;
907 }
908 #ifdef MAC
909 error = mac_sysvsem_check_semget(cred, &sema[semid]);
910 if (error != 0)
911 goto done2;
912 #endif
913 goto found;
914 }
915 }
916
917 DPRINTF(("need to allocate the semid_kernel\n"));
918 if (key == IPC_PRIVATE || (semflg & IPC_CREAT)) {
919 if (nsems <= 0 || nsems > seminfo.semmsl) {
920 DPRINTF(("nsems out of range (0<%d<=%d)\n", nsems,
921 seminfo.semmsl));
922 error = EINVAL;
923 goto done2;
924 }
925 if (nsems > seminfo.semmns - semtot) {
926 DPRINTF((
927 "not enough semaphores left (need %d, got %d)\n",
928 nsems, seminfo.semmns - semtot));
929 error = ENOSPC;
930 goto done2;
931 }
932 for (semid = 0; semid < seminfo.semmni; semid++) {
933 if ((sema[semid].u.sem_perm.mode & SEM_ALLOC) == 0)
934 break;
935 }
936 if (semid == seminfo.semmni) {
937 DPRINTF(("no more semid_kernel's available\n"));
938 error = ENOSPC;
939 goto done2;
940 }
941 DPRINTF(("semid %d is available\n", semid));
942 sema[semid].u.sem_perm.key = key;
943 sema[semid].u.sem_perm.cuid = cred->cr_uid;
944 sema[semid].u.sem_perm.uid = cred->cr_uid;
945 sema[semid].u.sem_perm.cgid = cred->cr_gid;
946 sema[semid].u.sem_perm.gid = cred->cr_gid;
947 sema[semid].u.sem_perm.mode = (semflg & 0777) | SEM_ALLOC;
948 sema[semid].u.sem_perm.seq =
949 (sema[semid].u.sem_perm.seq + 1) & 0x7fff;
950 sema[semid].u.sem_nsems = nsems;
951 sema[semid].u.sem_otime = 0;
952 sema[semid].u.sem_ctime = time_second;
953 sema[semid].u.sem_base = &sem[semtot];
954 semtot += nsems;
955 bzero(sema[semid].u.sem_base,
956 sizeof(sema[semid].u.sem_base[0])*nsems);
957 #ifdef MAC
958 mac_sysvsem_create(cred, &sema[semid]);
959 #endif
960 DPRINTF(("sembase = %p, next = %p\n",
961 sema[semid].u.sem_base, &sem[semtot]));
962 } else {
963 DPRINTF(("didn't find it and wasn't asked to create it\n"));
964 error = ENOENT;
965 goto done2;
966 }
967
968 found:
969 td->td_retval[0] = IXSEQ_TO_IPCID(semid, sema[semid].u.sem_perm);
970 done2:
971 mtx_unlock(&Giant);
972 return (error);
973 }
974
975 #ifndef _SYS_SYSPROTO_H_
976 struct semop_args {
977 int semid;
978 struct sembuf *sops;
979 size_t nsops;
980 };
981 #endif
982 int
983 semop(td, uap)
984 struct thread *td;
985 struct semop_args *uap;
986 {
987 #define SMALL_SOPS 8
988 struct sembuf small_sops[SMALL_SOPS];
989 int semid = uap->semid;
990 size_t nsops = uap->nsops;
991 struct sembuf *sops;
992 struct semid_kernel *semakptr;
993 struct sembuf *sopptr = 0;
994 struct sem *semptr = 0;
995 struct sem_undo *suptr;
996 struct mtx *sema_mtxp;
997 size_t i, j, k;
998 int error;
999 int do_wakeup, do_undos;
1000
1001 #ifdef SEM_DEBUG
1002 sops = NULL;
1003 #endif
1004 DPRINTF(("call to semop(%d, %p, %u)\n", semid, sops, nsops));
1005
1006 if (!jail_sysvipc_allowed && jailed(td->td_ucred))
1007 return (ENOSYS);
1008
1009 semid = IPCID_TO_IX(semid); /* Convert back to zero origin */
1010
1011 if (semid < 0 || semid >= seminfo.semmni)
1012 return (EINVAL);
1013
1014 /* Allocate memory for sem_ops */
1015 if (nsops <= SMALL_SOPS)
1016 sops = small_sops;
1017 else if (nsops <= seminfo.semopm)
1018 sops = malloc(nsops * sizeof(*sops), M_TEMP, M_WAITOK);
1019 else {
1020 DPRINTF(("too many sops (max=%d, nsops=%d)\n", seminfo.semopm,
1021 nsops));
1022 return (E2BIG);
1023 }
1024 if ((error = copyin(uap->sops, sops, nsops * sizeof(sops[0]))) != 0) {
1025 DPRINTF(("error = %d from copyin(%p, %p, %d)\n", error,
1026 uap->sops, sops, nsops * sizeof(sops[0])));
1027 if (sops != small_sops)
1028 free(sops, M_SEM);
1029 return (error);
1030 }
1031
1032 semakptr = &sema[semid];
1033 sema_mtxp = &sema_mtx[semid];
1034 mtx_lock(sema_mtxp);
1035 if ((semakptr->u.sem_perm.mode & SEM_ALLOC) == 0) {
1036 error = EINVAL;
1037 goto done2;
1038 }
1039 if (semakptr->u.sem_perm.seq != IPCID_TO_SEQ(uap->semid)) {
1040 error = EINVAL;
1041 goto done2;
1042 }
1043 /*
1044 * Initial pass thru sops to see what permissions are needed.
1045 * Also perform any checks that don't need repeating on each
1046 * attempt to satisfy the request vector.
1047 */
1048 j = 0; /* permission needed */
1049 do_undos = 0;
1050 for (i = 0; i < nsops; i++) {
1051 sopptr = &sops[i];
1052 if (sopptr->sem_num >= semakptr->u.sem_nsems) {
1053 error = EFBIG;
1054 goto done2;
1055 }
1056 if (sopptr->sem_flg & SEM_UNDO && sopptr->sem_op != 0)
1057 do_undos = 1;
1058 j |= (sopptr->sem_op == 0) ? SEM_R : SEM_A;
1059 }
1060
1061 if ((error = ipcperm(td, &semakptr->u.sem_perm, j))) {
1062 DPRINTF(("error = %d from ipaccess\n", error));
1063 goto done2;
1064 }
1065 #ifdef MAC
1066 error = mac_sysvsem_check_semop(td->td_ucred, semakptr, j);
1067 if (error != 0)
1068 goto done2;
1069 #endif
1070
1071 /*
1072 * Loop trying to satisfy the vector of requests.
1073 * If we reach a point where we must wait, any requests already
1074 * performed are rolled back and we go to sleep until some other
1075 * process wakes us up. At this point, we start all over again.
1076 *
1077 * This ensures that from the perspective of other tasks, a set
1078 * of requests is atomic (never partially satisfied).
1079 */
1080 for (;;) {
1081 do_wakeup = 0;
1082 error = 0; /* error return if necessary */
1083
1084 for (i = 0; i < nsops; i++) {
1085 sopptr = &sops[i];
1086 semptr = &semakptr->u.sem_base[sopptr->sem_num];
1087
1088 DPRINTF((
1089 "semop: semakptr=%p, sem_base=%p, "
1090 "semptr=%p, sem[%d]=%d : op=%d, flag=%s\n",
1091 semakptr, semakptr->u.sem_base, semptr,
1092 sopptr->sem_num, semptr->semval, sopptr->sem_op,
1093 (sopptr->sem_flg & IPC_NOWAIT) ?
1094 "nowait" : "wait"));
1095
1096 if (sopptr->sem_op < 0) {
1097 if (semptr->semval + sopptr->sem_op < 0) {
1098 DPRINTF(("semop: can't do it now\n"));
1099 break;
1100 } else {
1101 semptr->semval += sopptr->sem_op;
1102 if (semptr->semval == 0 &&
1103 semptr->semzcnt > 0)
1104 do_wakeup = 1;
1105 }
1106 } else if (sopptr->sem_op == 0) {
1107 if (semptr->semval != 0) {
1108 DPRINTF(("semop: not zero now\n"));
1109 break;
1110 }
1111 } else if (semptr->semval + sopptr->sem_op >
1112 seminfo.semvmx) {
1113 error = ERANGE;
1114 break;
1115 } else {
1116 if (semptr->semncnt > 0)
1117 do_wakeup = 1;
1118 semptr->semval += sopptr->sem_op;
1119 }
1120 }
1121
1122 /*
1123 * Did we get through the entire vector?
1124 */
1125 if (i >= nsops)
1126 goto done;
1127
1128 /*
1129 * No ... rollback anything that we've already done
1130 */
1131 DPRINTF(("semop: rollback 0 through %d\n", i-1));
1132 for (j = 0; j < i; j++)
1133 semakptr->u.sem_base[sops[j].sem_num].semval -=
1134 sops[j].sem_op;
1135
1136 /* If we detected an error, return it */
1137 if (error != 0)
1138 goto done2;
1139
1140 /*
1141 * If the request that we couldn't satisfy has the
1142 * NOWAIT flag set then return with EAGAIN.
1143 */
1144 if (sopptr->sem_flg & IPC_NOWAIT) {
1145 error = EAGAIN;
1146 goto done2;
1147 }
1148
1149 if (sopptr->sem_op == 0)
1150 semptr->semzcnt++;
1151 else
1152 semptr->semncnt++;
1153
1154 DPRINTF(("semop: good night!\n"));
1155 error = msleep(semakptr, sema_mtxp, (PZERO - 4) | PCATCH,
1156 "semwait", 0);
1157 DPRINTF(("semop: good morning (error=%d)!\n", error));
1158 /* return code is checked below, after sem[nz]cnt-- */
1159
1160 /*
1161 * Make sure that the semaphore still exists
1162 */
1163 if ((semakptr->u.sem_perm.mode & SEM_ALLOC) == 0 ||
1164 semakptr->u.sem_perm.seq != IPCID_TO_SEQ(uap->semid)) {
1165 error = EIDRM;
1166 goto done2;
1167 }
1168
1169 /*
1170 * Renew the semaphore's pointer after wakeup since
1171 * during msleep sem_base may have been modified and semptr
1172 * is not valid any more
1173 */
1174 semptr = &semakptr->u.sem_base[sopptr->sem_num];
1175
1176 /*
1177 * The semaphore is still alive. Readjust the count of
1178 * waiting processes.
1179 */
1180 if (sopptr->sem_op == 0)
1181 semptr->semzcnt--;
1182 else
1183 semptr->semncnt--;
1184
1185 /*
1186 * Is it really morning, or was our sleep interrupted?
1187 * (Delayed check of msleep() return code because we
1188 * need to decrement sem[nz]cnt either way.)
1189 */
1190 if (error != 0) {
1191 error = EINTR;
1192 goto done2;
1193 }
1194 DPRINTF(("semop: good morning!\n"));
1195 }
1196
1197 done:
1198 /*
1199 * Process any SEM_UNDO requests.
1200 */
1201 if (do_undos) {
1202 SEMUNDO_LOCK();
1203 suptr = NULL;
1204 for (i = 0; i < nsops; i++) {
1205 /*
1206 * We only need to deal with SEM_UNDO's for non-zero
1207 * op's.
1208 */
1209 int adjval;
1210
1211 if ((sops[i].sem_flg & SEM_UNDO) == 0)
1212 continue;
1213 adjval = sops[i].sem_op;
1214 if (adjval == 0)
1215 continue;
1216 error = semundo_adjust(td, &suptr, semid,
1217 sops[i].sem_num, -adjval);
1218 if (error == 0)
1219 continue;
1220
1221 /*
1222 * Oh-Oh! We ran out of either sem_undo's or undo's.
1223 * Rollback the adjustments to this point and then
1224 * rollback the semaphore ups and down so we can return
1225 * with an error with all structures restored. We
1226 * rollback the undo's in the exact reverse order that
1227 * we applied them. This guarantees that we won't run
1228 * out of space as we roll things back out.
1229 */
1230 for (j = 0; j < i; j++) {
1231 k = i - j - 1;
1232 if ((sops[k].sem_flg & SEM_UNDO) == 0)
1233 continue;
1234 adjval = sops[k].sem_op;
1235 if (adjval == 0)
1236 continue;
1237 if (semundo_adjust(td, &suptr, semid,
1238 sops[k].sem_num, adjval) != 0)
1239 panic("semop - can't undo undos");
1240 }
1241
1242 for (j = 0; j < nsops; j++)
1243 semakptr->u.sem_base[sops[j].sem_num].semval -=
1244 sops[j].sem_op;
1245
1246 DPRINTF(("error = %d from semundo_adjust\n", error));
1247 SEMUNDO_UNLOCK();
1248 goto done2;
1249 } /* loop through the sops */
1250 SEMUNDO_UNLOCK();
1251 } /* if (do_undos) */
1252
1253 /* We're definitely done - set the sempid's and time */
1254 for (i = 0; i < nsops; i++) {
1255 sopptr = &sops[i];
1256 semptr = &semakptr->u.sem_base[sopptr->sem_num];
1257 semptr->sempid = td->td_proc->p_pid;
1258 }
1259 semakptr->u.sem_otime = time_second;
1260
1261 /*
1262 * Do a wakeup if any semaphore was up'd whilst something was
1263 * sleeping on it.
1264 */
1265 if (do_wakeup) {
1266 DPRINTF(("semop: doing wakeup\n"));
1267 wakeup(semakptr);
1268 DPRINTF(("semop: back from wakeup\n"));
1269 }
1270 DPRINTF(("semop: done\n"));
1271 td->td_retval[0] = 0;
1272 done2:
1273 mtx_unlock(sema_mtxp);
1274 if (sops != small_sops)
1275 free(sops, M_SEM);
1276 return (error);
1277 }
1278
1279 /*
1280 * Go through the undo structures for this process and apply the adjustments to
1281 * semaphores.
1282 */
1283 static void
1284 semexit_myhook(arg, p)
1285 void *arg;
1286 struct proc *p;
1287 {
1288 struct sem_undo *suptr;
1289 struct sem_undo **supptr;
1290
1291 /*
1292 * Go through the chain of undo vectors looking for one
1293 * associated with this process.
1294 */
1295 SEMUNDO_LOCK();
1296 SLIST_FOREACH_PREVPTR(suptr, supptr, &semu_list, un_next) {
1297 if (suptr->un_proc == p) {
1298 *supptr = SLIST_NEXT(suptr, un_next);
1299 break;
1300 }
1301 }
1302 SEMUNDO_UNLOCK();
1303
1304 if (suptr == NULL)
1305 return;
1306
1307 DPRINTF(("proc @%p has undo structure with %d entries\n", p,
1308 suptr->un_cnt));
1309
1310 /*
1311 * If there are any active undo elements then process them.
1312 */
1313 if (suptr->un_cnt > 0) {
1314 int ix;
1315
1316 for (ix = 0; ix < suptr->un_cnt; ix++) {
1317 int semid = suptr->un_ent[ix].un_id;
1318 int semnum = suptr->un_ent[ix].un_num;
1319 int adjval = suptr->un_ent[ix].un_adjval;
1320 struct semid_kernel *semakptr;
1321 struct mtx *sema_mtxp;
1322
1323 semakptr = &sema[semid];
1324 sema_mtxp = &sema_mtx[semid];
1325 mtx_lock(sema_mtxp);
1326 SEMUNDO_LOCK();
1327 if ((semakptr->u.sem_perm.mode & SEM_ALLOC) == 0)
1328 panic("semexit - semid not allocated");
1329 if (semnum >= semakptr->u.sem_nsems)
1330 panic("semexit - semnum out of range");
1331
1332 DPRINTF((
1333 "semexit: %p id=%d num=%d(adj=%d) ; sem=%d\n",
1334 suptr->un_proc, suptr->un_ent[ix].un_id,
1335 suptr->un_ent[ix].un_num,
1336 suptr->un_ent[ix].un_adjval,
1337 semakptr->u.sem_base[semnum].semval));
1338
1339 if (adjval < 0) {
1340 if (semakptr->u.sem_base[semnum].semval <
1341 -adjval)
1342 semakptr->u.sem_base[semnum].semval = 0;
1343 else
1344 semakptr->u.sem_base[semnum].semval +=
1345 adjval;
1346 } else
1347 semakptr->u.sem_base[semnum].semval += adjval;
1348
1349 wakeup(semakptr);
1350 DPRINTF(("semexit: back from wakeup\n"));
1351 mtx_unlock(sema_mtxp);
1352 SEMUNDO_UNLOCK();
1353 }
1354 }
1355
1356 /*
1357 * Deallocate the undo vector.
1358 */
1359 DPRINTF(("removing vector\n"));
1360 SEMUNDO_LOCK();
1361 suptr->un_proc = NULL;
1362 SEMUNDO_UNLOCK();
1363 }
1364
1365 static int
1366 sysctl_sema(SYSCTL_HANDLER_ARGS)
1367 {
1368
1369 return (SYSCTL_OUT(req, sema,
1370 sizeof(struct semid_kernel) * seminfo.semmni));
1371 }
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