FreeBSD/Linux Kernel Cross Reference
sys/kern/sysv_sem.c
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: releng/8.3/sys/kern/sysv_sem.c 215629 2010-11-21 12:47:54Z brucec $");
41
42 #include "opt_compat.h"
43 #include "opt_sysvipc.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 int 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 semseq, int semnum, int adjval);
92 static void semundo_clear(int semid, int semnum);
93
94 static struct mtx sem_mtx; /* semaphore global lock */
95 static struct mtx sem_undo_mtx;
96 static int semtot = 0;
97 static struct semid_kernel *sema; /* semaphore id pool */
98 static struct mtx *sema_mtx; /* semaphore id pool mutexes*/
99 static struct sem *sem; /* semaphore pool */
100 LIST_HEAD(, sem_undo) semu_list; /* list of active undo structures */
101 LIST_HEAD(, sem_undo) semu_free_list; /* list of free undo structures */
102 static int *semu; /* undo structure pool */
103 static eventhandler_tag semexit_tag;
104
105 #define SEMUNDO_MTX sem_undo_mtx
106 #define SEMUNDO_LOCK() mtx_lock(&SEMUNDO_MTX);
107 #define SEMUNDO_UNLOCK() mtx_unlock(&SEMUNDO_MTX);
108 #define SEMUNDO_LOCKASSERT(how) mtx_assert(&SEMUNDO_MTX, (how));
109
110 struct sem {
111 u_short semval; /* semaphore value */
112 pid_t sempid; /* pid of last operation */
113 u_short semncnt; /* # awaiting semval > cval */
114 u_short semzcnt; /* # awaiting semval = 0 */
115 };
116
117 /*
118 * Undo structure (one per process)
119 */
120 struct sem_undo {
121 LIST_ENTRY(sem_undo) un_next; /* ptr to next active undo structure */
122 struct proc *un_proc; /* owner of this structure */
123 short un_cnt; /* # of active entries */
124 struct undo {
125 short un_adjval; /* adjust on exit values */
126 short un_num; /* semaphore # */
127 int un_id; /* semid */
128 unsigned short un_seq;
129 } un_ent[1]; /* undo entries */
130 };
131
132 /*
133 * Configuration parameters
134 */
135 #ifndef SEMMNI
136 #define SEMMNI 10 /* # of semaphore identifiers */
137 #endif
138 #ifndef SEMMNS
139 #define SEMMNS 60 /* # of semaphores in system */
140 #endif
141 #ifndef SEMUME
142 #define SEMUME 10 /* max # of undo entries per process */
143 #endif
144 #ifndef SEMMNU
145 #define SEMMNU 30 /* # of undo structures in system */
146 #endif
147
148 /* shouldn't need tuning */
149 #ifndef SEMMAP
150 #define SEMMAP 30 /* # of entries in semaphore map */
151 #endif
152 #ifndef SEMMSL
153 #define SEMMSL SEMMNS /* max # of semaphores per id */
154 #endif
155 #ifndef SEMOPM
156 #define SEMOPM 100 /* max # of operations per semop call */
157 #endif
158
159 #define SEMVMX 32767 /* semaphore maximum value */
160 #define SEMAEM 16384 /* adjust on exit max value */
161
162 /*
163 * Due to the way semaphore memory is allocated, we have to ensure that
164 * SEMUSZ is properly aligned.
165 */
166
167 #define SEM_ALIGN(bytes) (((bytes) + (sizeof(long) - 1)) & ~(sizeof(long) - 1))
168
169 /* actual size of an undo structure */
170 #define SEMUSZ SEM_ALIGN(offsetof(struct sem_undo, un_ent[SEMUME]))
171
172 /*
173 * Macro to find a particular sem_undo vector
174 */
175 #define SEMU(ix) \
176 ((struct sem_undo *)(((intptr_t)semu)+ix * seminfo.semusz))
177
178 /*
179 * semaphore info struct
180 */
181 struct seminfo seminfo = {
182 SEMMAP, /* # of entries in semaphore map */
183 SEMMNI, /* # of semaphore identifiers */
184 SEMMNS, /* # of semaphores in system */
185 SEMMNU, /* # of undo structures in system */
186 SEMMSL, /* max # of semaphores per id */
187 SEMOPM, /* max # of operations per semop call */
188 SEMUME, /* max # of undo entries per process */
189 SEMUSZ, /* size in bytes of undo structure */
190 SEMVMX, /* semaphore maximum value */
191 SEMAEM /* adjust on exit max value */
192 };
193
194 SYSCTL_INT(_kern_ipc, OID_AUTO, semmap, CTLFLAG_RW, &seminfo.semmap, 0,
195 "Number of entries in the semaphore map");
196 SYSCTL_INT(_kern_ipc, OID_AUTO, semmni, CTLFLAG_RDTUN, &seminfo.semmni, 0,
197 "Number of semaphore identifiers");
198 SYSCTL_INT(_kern_ipc, OID_AUTO, semmns, CTLFLAG_RDTUN, &seminfo.semmns, 0,
199 "Maximum number of semaphores in the system");
200 SYSCTL_INT(_kern_ipc, OID_AUTO, semmnu, CTLFLAG_RDTUN, &seminfo.semmnu, 0,
201 "Maximum number of undo structures in the system");
202 SYSCTL_INT(_kern_ipc, OID_AUTO, semmsl, CTLFLAG_RW, &seminfo.semmsl, 0,
203 "Max semaphores per id");
204 SYSCTL_INT(_kern_ipc, OID_AUTO, semopm, CTLFLAG_RDTUN, &seminfo.semopm, 0,
205 "Max operations per semop call");
206 SYSCTL_INT(_kern_ipc, OID_AUTO, semume, CTLFLAG_RDTUN, &seminfo.semume, 0,
207 "Max undo entries per process");
208 SYSCTL_INT(_kern_ipc, OID_AUTO, semusz, CTLFLAG_RDTUN, &seminfo.semusz, 0,
209 "Size in bytes of undo structure");
210 SYSCTL_INT(_kern_ipc, OID_AUTO, semvmx, CTLFLAG_RW, &seminfo.semvmx, 0,
211 "Semaphore maximum value");
212 SYSCTL_INT(_kern_ipc, OID_AUTO, semaem, CTLFLAG_RW, &seminfo.semaem, 0,
213 "Adjust on exit max value");
214 SYSCTL_PROC(_kern_ipc, OID_AUTO, sema, CTLFLAG_RD,
215 NULL, 0, sysctl_sema, "", "Semaphore id pool");
216
217 static struct syscall_helper_data sem_syscalls[] = {
218 SYSCALL_INIT_HELPER(__semctl),
219 SYSCALL_INIT_HELPER(semget),
220 SYSCALL_INIT_HELPER(semop),
221 #if defined(COMPAT_FREEBSD4) || defined(COMPAT_FREEBSD5) || \
222 defined(COMPAT_FREEBSD6) || defined(COMPAT_FREEBSD7)
223 SYSCALL_INIT_HELPER(semsys),
224 SYSCALL_INIT_HELPER(freebsd7___semctl),
225 #endif
226 SYSCALL_INIT_LAST
227 };
228
229 #ifdef COMPAT_FREEBSD32
230 #include <compat/freebsd32/freebsd32.h>
231 #include <compat/freebsd32/freebsd32_ipc.h>
232 #include <compat/freebsd32/freebsd32_proto.h>
233 #include <compat/freebsd32/freebsd32_signal.h>
234 #include <compat/freebsd32/freebsd32_syscall.h>
235 #include <compat/freebsd32/freebsd32_util.h>
236
237 static struct syscall_helper_data sem32_syscalls[] = {
238 SYSCALL32_INIT_HELPER(freebsd32_semctl),
239 SYSCALL32_INIT_HELPER(semget),
240 SYSCALL32_INIT_HELPER(semop),
241 SYSCALL32_INIT_HELPER(freebsd32_semsys),
242 #if defined(COMPAT_FREEBSD4) || defined(COMPAT_FREEBSD5) || \
243 defined(COMPAT_FREEBSD6) || defined(COMPAT_FREEBSD7)
244 SYSCALL32_INIT_HELPER(freebsd7_freebsd32_semctl),
245 #endif
246 SYSCALL_INIT_LAST
247 };
248 #endif
249
250 static int
251 seminit(void)
252 {
253 int i, error;
254
255 TUNABLE_INT_FETCH("kern.ipc.semmap", &seminfo.semmap);
256 TUNABLE_INT_FETCH("kern.ipc.semmni", &seminfo.semmni);
257 TUNABLE_INT_FETCH("kern.ipc.semmns", &seminfo.semmns);
258 TUNABLE_INT_FETCH("kern.ipc.semmnu", &seminfo.semmnu);
259 TUNABLE_INT_FETCH("kern.ipc.semmsl", &seminfo.semmsl);
260 TUNABLE_INT_FETCH("kern.ipc.semopm", &seminfo.semopm);
261 TUNABLE_INT_FETCH("kern.ipc.semume", &seminfo.semume);
262 TUNABLE_INT_FETCH("kern.ipc.semusz", &seminfo.semusz);
263 TUNABLE_INT_FETCH("kern.ipc.semvmx", &seminfo.semvmx);
264 TUNABLE_INT_FETCH("kern.ipc.semaem", &seminfo.semaem);
265
266 sem = malloc(sizeof(struct sem) * seminfo.semmns, M_SEM, M_WAITOK);
267 sema = malloc(sizeof(struct semid_kernel) * seminfo.semmni, M_SEM,
268 M_WAITOK);
269 sema_mtx = malloc(sizeof(struct mtx) * seminfo.semmni, M_SEM,
270 M_WAITOK | M_ZERO);
271 semu = malloc(seminfo.semmnu * seminfo.semusz, M_SEM, M_WAITOK);
272
273 for (i = 0; i < seminfo.semmni; i++) {
274 sema[i].u.sem_base = 0;
275 sema[i].u.sem_perm.mode = 0;
276 sema[i].u.sem_perm.seq = 0;
277 #ifdef MAC
278 mac_sysvsem_init(&sema[i]);
279 #endif
280 }
281 for (i = 0; i < seminfo.semmni; i++)
282 mtx_init(&sema_mtx[i], "semid", NULL, MTX_DEF);
283 LIST_INIT(&semu_free_list);
284 for (i = 0; i < seminfo.semmnu; i++) {
285 struct sem_undo *suptr = SEMU(i);
286 suptr->un_proc = NULL;
287 LIST_INSERT_HEAD(&semu_free_list, suptr, un_next);
288 }
289 LIST_INIT(&semu_list);
290 mtx_init(&sem_mtx, "sem", NULL, MTX_DEF);
291 mtx_init(&sem_undo_mtx, "semu", NULL, MTX_DEF);
292 semexit_tag = EVENTHANDLER_REGISTER(process_exit, semexit_myhook, NULL,
293 EVENTHANDLER_PRI_ANY);
294
295 error = syscall_helper_register(sem_syscalls);
296 if (error != 0)
297 return (error);
298 #ifdef COMPAT_FREEBSD32
299 error = syscall32_helper_register(sem32_syscalls);
300 if (error != 0)
301 return (error);
302 #endif
303 return (0);
304 }
305
306 static int
307 semunload(void)
308 {
309 int i;
310
311 /* XXXKIB */
312 if (semtot != 0)
313 return (EBUSY);
314
315 #ifdef COMPAT_FREEBSD32
316 syscall32_helper_unregister(sem32_syscalls);
317 #endif
318 syscall_helper_unregister(sem_syscalls);
319 EVENTHANDLER_DEREGISTER(process_exit, semexit_tag);
320 #ifdef MAC
321 for (i = 0; i < seminfo.semmni; i++)
322 mac_sysvsem_destroy(&sema[i]);
323 #endif
324 free(sem, M_SEM);
325 free(sema, M_SEM);
326 free(semu, M_SEM);
327 for (i = 0; i < seminfo.semmni; i++)
328 mtx_destroy(&sema_mtx[i]);
329 free(sema_mtx, M_SEM);
330 mtx_destroy(&sem_mtx);
331 mtx_destroy(&sem_undo_mtx);
332 return (0);
333 }
334
335 static int
336 sysvsem_modload(struct module *module, int cmd, void *arg)
337 {
338 int error = 0;
339
340 switch (cmd) {
341 case MOD_LOAD:
342 error = seminit();
343 if (error != 0)
344 semunload();
345 break;
346 case MOD_UNLOAD:
347 error = semunload();
348 break;
349 case MOD_SHUTDOWN:
350 break;
351 default:
352 error = EINVAL;
353 break;
354 }
355 return (error);
356 }
357
358 static moduledata_t sysvsem_mod = {
359 "sysvsem",
360 &sysvsem_modload,
361 NULL
362 };
363
364 DECLARE_MODULE(sysvsem, sysvsem_mod, SI_SUB_SYSV_SEM, SI_ORDER_FIRST);
365 MODULE_VERSION(sysvsem, 1);
366
367 /*
368 * Allocate a new sem_undo structure for a process
369 * (returns ptr to structure or NULL if no more room)
370 */
371
372 static struct sem_undo *
373 semu_alloc(struct thread *td)
374 {
375 struct sem_undo *suptr;
376
377 SEMUNDO_LOCKASSERT(MA_OWNED);
378 if ((suptr = LIST_FIRST(&semu_free_list)) == NULL)
379 return (NULL);
380 LIST_REMOVE(suptr, un_next);
381 LIST_INSERT_HEAD(&semu_list, suptr, un_next);
382 suptr->un_cnt = 0;
383 suptr->un_proc = td->td_proc;
384 return (suptr);
385 }
386
387 static int
388 semu_try_free(struct sem_undo *suptr)
389 {
390
391 SEMUNDO_LOCKASSERT(MA_OWNED);
392
393 if (suptr->un_cnt != 0)
394 return (0);
395 LIST_REMOVE(suptr, un_next);
396 LIST_INSERT_HEAD(&semu_free_list, suptr, un_next);
397 return (1);
398 }
399
400 /*
401 * Adjust a particular entry for a particular proc
402 */
403
404 static int
405 semundo_adjust(struct thread *td, struct sem_undo **supptr, int semid,
406 int semseq, int semnum, int adjval)
407 {
408 struct proc *p = td->td_proc;
409 struct sem_undo *suptr;
410 struct undo *sunptr;
411 int i;
412
413 SEMUNDO_LOCKASSERT(MA_OWNED);
414 /* Look for and remember the sem_undo if the caller doesn't provide
415 it */
416
417 suptr = *supptr;
418 if (suptr == NULL) {
419 LIST_FOREACH(suptr, &semu_list, un_next) {
420 if (suptr->un_proc == p) {
421 *supptr = suptr;
422 break;
423 }
424 }
425 if (suptr == NULL) {
426 if (adjval == 0)
427 return(0);
428 suptr = semu_alloc(td);
429 if (suptr == NULL)
430 return (ENOSPC);
431 *supptr = suptr;
432 }
433 }
434
435 /*
436 * Look for the requested entry and adjust it (delete if adjval becomes
437 * 0).
438 */
439 sunptr = &suptr->un_ent[0];
440 for (i = 0; i < suptr->un_cnt; i++, sunptr++) {
441 if (sunptr->un_id != semid || sunptr->un_num != semnum)
442 continue;
443 if (adjval != 0) {
444 adjval += sunptr->un_adjval;
445 if (adjval > seminfo.semaem || adjval < -seminfo.semaem)
446 return (ERANGE);
447 }
448 sunptr->un_adjval = adjval;
449 if (sunptr->un_adjval == 0) {
450 suptr->un_cnt--;
451 if (i < suptr->un_cnt)
452 suptr->un_ent[i] =
453 suptr->un_ent[suptr->un_cnt];
454 if (suptr->un_cnt == 0)
455 semu_try_free(suptr);
456 }
457 return (0);
458 }
459
460 /* Didn't find the right entry - create it */
461 if (adjval == 0)
462 return (0);
463 if (adjval > seminfo.semaem || adjval < -seminfo.semaem)
464 return (ERANGE);
465 if (suptr->un_cnt != seminfo.semume) {
466 sunptr = &suptr->un_ent[suptr->un_cnt];
467 suptr->un_cnt++;
468 sunptr->un_adjval = adjval;
469 sunptr->un_id = semid;
470 sunptr->un_num = semnum;
471 sunptr->un_seq = semseq;
472 } else
473 return (EINVAL);
474 return (0);
475 }
476
477 static void
478 semundo_clear(int semid, int semnum)
479 {
480 struct sem_undo *suptr, *suptr1;
481 struct undo *sunptr;
482 int i;
483
484 SEMUNDO_LOCKASSERT(MA_OWNED);
485 LIST_FOREACH_SAFE(suptr, &semu_list, un_next, suptr1) {
486 sunptr = &suptr->un_ent[0];
487 for (i = 0; i < suptr->un_cnt; i++, sunptr++) {
488 if (sunptr->un_id != semid)
489 continue;
490 if (semnum == -1 || sunptr->un_num == semnum) {
491 suptr->un_cnt--;
492 if (i < suptr->un_cnt) {
493 suptr->un_ent[i] =
494 suptr->un_ent[suptr->un_cnt];
495 continue;
496 }
497 semu_try_free(suptr);
498 }
499 if (semnum != -1)
500 break;
501 }
502 }
503 }
504
505 static int
506 semvalid(int semid, struct semid_kernel *semakptr)
507 {
508
509 return ((semakptr->u.sem_perm.mode & SEM_ALLOC) == 0 ||
510 semakptr->u.sem_perm.seq != IPCID_TO_SEQ(semid) ? EINVAL : 0);
511 }
512
513 /*
514 * Note that the user-mode half of this passes a union, not a pointer.
515 */
516 #ifndef _SYS_SYSPROTO_H_
517 struct __semctl_args {
518 int semid;
519 int semnum;
520 int cmd;
521 union semun *arg;
522 };
523 #endif
524 int
525 __semctl(struct thread *td, struct __semctl_args *uap)
526 {
527 struct semid_ds dsbuf;
528 union semun arg, semun;
529 register_t rval;
530 int error;
531
532 switch (uap->cmd) {
533 case SEM_STAT:
534 case IPC_SET:
535 case IPC_STAT:
536 case GETALL:
537 case SETVAL:
538 case SETALL:
539 error = copyin(uap->arg, &arg, sizeof(arg));
540 if (error)
541 return (error);
542 break;
543 }
544
545 switch (uap->cmd) {
546 case SEM_STAT:
547 case IPC_STAT:
548 semun.buf = &dsbuf;
549 break;
550 case IPC_SET:
551 error = copyin(arg.buf, &dsbuf, sizeof(dsbuf));
552 if (error)
553 return (error);
554 semun.buf = &dsbuf;
555 break;
556 case GETALL:
557 case SETALL:
558 semun.array = arg.array;
559 break;
560 case SETVAL:
561 semun.val = arg.val;
562 break;
563 }
564
565 error = kern_semctl(td, uap->semid, uap->semnum, uap->cmd, &semun,
566 &rval);
567 if (error)
568 return (error);
569
570 switch (uap->cmd) {
571 case SEM_STAT:
572 case IPC_STAT:
573 error = copyout(&dsbuf, arg.buf, sizeof(dsbuf));
574 break;
575 }
576
577 if (error == 0)
578 td->td_retval[0] = rval;
579 return (error);
580 }
581
582 int
583 kern_semctl(struct thread *td, int semid, int semnum, int cmd,
584 union semun *arg, register_t *rval)
585 {
586 u_short *array;
587 struct ucred *cred = td->td_ucred;
588 int i, error;
589 struct semid_ds *sbuf;
590 struct semid_kernel *semakptr;
591 struct mtx *sema_mtxp;
592 u_short usval, count;
593 int semidx;
594
595 DPRINTF(("call to semctl(%d, %d, %d, 0x%p)\n",
596 semid, semnum, cmd, arg));
597 if (!prison_allow(td->td_ucred, PR_ALLOW_SYSVIPC))
598 return (ENOSYS);
599
600 array = NULL;
601
602 switch(cmd) {
603 case SEM_STAT:
604 /*
605 * For this command we assume semid is an array index
606 * rather than an IPC id.
607 */
608 if (semid < 0 || semid >= seminfo.semmni)
609 return (EINVAL);
610 semakptr = &sema[semid];
611 sema_mtxp = &sema_mtx[semid];
612 mtx_lock(sema_mtxp);
613 if ((semakptr->u.sem_perm.mode & SEM_ALLOC) == 0) {
614 error = EINVAL;
615 goto done2;
616 }
617 if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_R)))
618 goto done2;
619 #ifdef MAC
620 error = mac_sysvsem_check_semctl(cred, semakptr, cmd);
621 if (error != 0)
622 goto done2;
623 #endif
624 bcopy(&semakptr->u, arg->buf, sizeof(struct semid_ds));
625 *rval = IXSEQ_TO_IPCID(semid, semakptr->u.sem_perm);
626 mtx_unlock(sema_mtxp);
627 return (0);
628 }
629
630 semidx = IPCID_TO_IX(semid);
631 if (semidx < 0 || semidx >= seminfo.semmni)
632 return (EINVAL);
633
634 semakptr = &sema[semidx];
635 sema_mtxp = &sema_mtx[semidx];
636 if (cmd == IPC_RMID)
637 mtx_lock(&sem_mtx);
638 mtx_lock(sema_mtxp);
639 #ifdef MAC
640 error = mac_sysvsem_check_semctl(cred, semakptr, cmd);
641 if (error != 0)
642 goto done2;
643 #endif
644
645 error = 0;
646 *rval = 0;
647
648 switch (cmd) {
649 case IPC_RMID:
650 if ((error = semvalid(semid, semakptr)) != 0)
651 goto done2;
652 if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_M)))
653 goto done2;
654 semakptr->u.sem_perm.cuid = cred->cr_uid;
655 semakptr->u.sem_perm.uid = cred->cr_uid;
656 semakptr->u.sem_perm.mode = 0;
657 SEMUNDO_LOCK();
658 semundo_clear(semidx, -1);
659 SEMUNDO_UNLOCK();
660 #ifdef MAC
661 mac_sysvsem_cleanup(semakptr);
662 #endif
663 wakeup(semakptr);
664 for (i = 0; i < seminfo.semmni; i++) {
665 if ((sema[i].u.sem_perm.mode & SEM_ALLOC) &&
666 sema[i].u.sem_base > semakptr->u.sem_base)
667 mtx_lock_flags(&sema_mtx[i], LOP_DUPOK);
668 }
669 for (i = semakptr->u.sem_base - sem; i < semtot; i++)
670 sem[i] = sem[i + semakptr->u.sem_nsems];
671 for (i = 0; i < seminfo.semmni; i++) {
672 if ((sema[i].u.sem_perm.mode & SEM_ALLOC) &&
673 sema[i].u.sem_base > semakptr->u.sem_base) {
674 sema[i].u.sem_base -= semakptr->u.sem_nsems;
675 mtx_unlock(&sema_mtx[i]);
676 }
677 }
678 semtot -= semakptr->u.sem_nsems;
679 break;
680
681 case IPC_SET:
682 if ((error = semvalid(semid, semakptr)) != 0)
683 goto done2;
684 if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_M)))
685 goto done2;
686 sbuf = arg->buf;
687 semakptr->u.sem_perm.uid = sbuf->sem_perm.uid;
688 semakptr->u.sem_perm.gid = sbuf->sem_perm.gid;
689 semakptr->u.sem_perm.mode = (semakptr->u.sem_perm.mode &
690 ~0777) | (sbuf->sem_perm.mode & 0777);
691 semakptr->u.sem_ctime = time_second;
692 break;
693
694 case IPC_STAT:
695 if ((error = semvalid(semid, semakptr)) != 0)
696 goto done2;
697 if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_R)))
698 goto done2;
699 bcopy(&semakptr->u, arg->buf, sizeof(struct semid_ds));
700 break;
701
702 case GETNCNT:
703 if ((error = semvalid(semid, semakptr)) != 0)
704 goto done2;
705 if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_R)))
706 goto done2;
707 if (semnum < 0 || semnum >= semakptr->u.sem_nsems) {
708 error = EINVAL;
709 goto done2;
710 }
711 *rval = semakptr->u.sem_base[semnum].semncnt;
712 break;
713
714 case GETPID:
715 if ((error = semvalid(semid, semakptr)) != 0)
716 goto done2;
717 if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_R)))
718 goto done2;
719 if (semnum < 0 || semnum >= semakptr->u.sem_nsems) {
720 error = EINVAL;
721 goto done2;
722 }
723 *rval = semakptr->u.sem_base[semnum].sempid;
724 break;
725
726 case GETVAL:
727 if ((error = semvalid(semid, semakptr)) != 0)
728 goto done2;
729 if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_R)))
730 goto done2;
731 if (semnum < 0 || semnum >= semakptr->u.sem_nsems) {
732 error = EINVAL;
733 goto done2;
734 }
735 *rval = semakptr->u.sem_base[semnum].semval;
736 break;
737
738 case GETALL:
739 /*
740 * Unfortunately, callers of this function don't know
741 * in advance how many semaphores are in this set.
742 * While we could just allocate the maximum size array
743 * and pass the actual size back to the caller, that
744 * won't work for SETALL since we can't copyin() more
745 * data than the user specified as we may return a
746 * spurious EFAULT.
747 *
748 * Note that the number of semaphores in a set is
749 * fixed for the life of that set. The only way that
750 * the 'count' could change while are blocked in
751 * malloc() is if this semaphore set were destroyed
752 * and a new one created with the same index.
753 * However, semvalid() will catch that due to the
754 * sequence number unless exactly 0x8000 (or a
755 * multiple thereof) semaphore sets for the same index
756 * are created and destroyed while we are in malloc!
757 *
758 */
759 count = semakptr->u.sem_nsems;
760 mtx_unlock(sema_mtxp);
761 array = malloc(sizeof(*array) * count, M_TEMP, M_WAITOK);
762 mtx_lock(sema_mtxp);
763 if ((error = semvalid(semid, semakptr)) != 0)
764 goto done2;
765 KASSERT(count == semakptr->u.sem_nsems, ("nsems changed"));
766 if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_R)))
767 goto done2;
768 for (i = 0; i < semakptr->u.sem_nsems; i++)
769 array[i] = semakptr->u.sem_base[i].semval;
770 mtx_unlock(sema_mtxp);
771 error = copyout(array, arg->array, count * sizeof(*array));
772 mtx_lock(sema_mtxp);
773 break;
774
775 case GETZCNT:
776 if ((error = semvalid(semid, semakptr)) != 0)
777 goto done2;
778 if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_R)))
779 goto done2;
780 if (semnum < 0 || semnum >= semakptr->u.sem_nsems) {
781 error = EINVAL;
782 goto done2;
783 }
784 *rval = semakptr->u.sem_base[semnum].semzcnt;
785 break;
786
787 case SETVAL:
788 if ((error = semvalid(semid, semakptr)) != 0)
789 goto done2;
790 if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_W)))
791 goto done2;
792 if (semnum < 0 || semnum >= semakptr->u.sem_nsems) {
793 error = EINVAL;
794 goto done2;
795 }
796 if (arg->val < 0 || arg->val > seminfo.semvmx) {
797 error = ERANGE;
798 goto done2;
799 }
800 semakptr->u.sem_base[semnum].semval = arg->val;
801 SEMUNDO_LOCK();
802 semundo_clear(semidx, semnum);
803 SEMUNDO_UNLOCK();
804 wakeup(semakptr);
805 break;
806
807 case SETALL:
808 /*
809 * See comment on GETALL for why 'count' shouldn't change
810 * and why we require a userland buffer.
811 */
812 count = semakptr->u.sem_nsems;
813 mtx_unlock(sema_mtxp);
814 array = malloc(sizeof(*array) * count, M_TEMP, M_WAITOK);
815 error = copyin(arg->array, array, count * sizeof(*array));
816 mtx_lock(sema_mtxp);
817 if (error)
818 break;
819 if ((error = semvalid(semid, semakptr)) != 0)
820 goto done2;
821 KASSERT(count == semakptr->u.sem_nsems, ("nsems changed"));
822 if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_W)))
823 goto done2;
824 for (i = 0; i < semakptr->u.sem_nsems; i++) {
825 usval = array[i];
826 if (usval > seminfo.semvmx) {
827 error = ERANGE;
828 break;
829 }
830 semakptr->u.sem_base[i].semval = usval;
831 }
832 SEMUNDO_LOCK();
833 semundo_clear(semidx, -1);
834 SEMUNDO_UNLOCK();
835 wakeup(semakptr);
836 break;
837
838 default:
839 error = EINVAL;
840 break;
841 }
842
843 done2:
844 mtx_unlock(sema_mtxp);
845 if (cmd == IPC_RMID)
846 mtx_unlock(&sem_mtx);
847 if (array != NULL)
848 free(array, M_TEMP);
849 return(error);
850 }
851
852 #ifndef _SYS_SYSPROTO_H_
853 struct semget_args {
854 key_t key;
855 int nsems;
856 int semflg;
857 };
858 #endif
859 int
860 semget(struct thread *td, struct semget_args *uap)
861 {
862 int semid, error = 0;
863 int key = uap->key;
864 int nsems = uap->nsems;
865 int semflg = uap->semflg;
866 struct ucred *cred = td->td_ucred;
867
868 DPRINTF(("semget(0x%x, %d, 0%o)\n", key, nsems, semflg));
869 if (!prison_allow(td->td_ucred, PR_ALLOW_SYSVIPC))
870 return (ENOSYS);
871
872 mtx_lock(&sem_mtx);
873 if (key != IPC_PRIVATE) {
874 for (semid = 0; semid < seminfo.semmni; semid++) {
875 if ((sema[semid].u.sem_perm.mode & SEM_ALLOC) &&
876 sema[semid].u.sem_perm.key == key)
877 break;
878 }
879 if (semid < seminfo.semmni) {
880 DPRINTF(("found public key\n"));
881 if ((error = ipcperm(td, &sema[semid].u.sem_perm,
882 semflg & 0700))) {
883 goto done2;
884 }
885 if (nsems > 0 && sema[semid].u.sem_nsems < nsems) {
886 DPRINTF(("too small\n"));
887 error = EINVAL;
888 goto done2;
889 }
890 if ((semflg & IPC_CREAT) && (semflg & IPC_EXCL)) {
891 DPRINTF(("not exclusive\n"));
892 error = EEXIST;
893 goto done2;
894 }
895 #ifdef MAC
896 error = mac_sysvsem_check_semget(cred, &sema[semid]);
897 if (error != 0)
898 goto done2;
899 #endif
900 goto found;
901 }
902 }
903
904 DPRINTF(("need to allocate the semid_kernel\n"));
905 if (key == IPC_PRIVATE || (semflg & IPC_CREAT)) {
906 if (nsems <= 0 || nsems > seminfo.semmsl) {
907 DPRINTF(("nsems out of range (0<%d<=%d)\n", nsems,
908 seminfo.semmsl));
909 error = EINVAL;
910 goto done2;
911 }
912 if (nsems > seminfo.semmns - semtot) {
913 DPRINTF((
914 "not enough semaphores left (need %d, got %d)\n",
915 nsems, seminfo.semmns - semtot));
916 error = ENOSPC;
917 goto done2;
918 }
919 for (semid = 0; semid < seminfo.semmni; semid++) {
920 if ((sema[semid].u.sem_perm.mode & SEM_ALLOC) == 0)
921 break;
922 }
923 if (semid == seminfo.semmni) {
924 DPRINTF(("no more semid_kernel's available\n"));
925 error = ENOSPC;
926 goto done2;
927 }
928 DPRINTF(("semid %d is available\n", semid));
929 mtx_lock(&sema_mtx[semid]);
930 KASSERT((sema[semid].u.sem_perm.mode & SEM_ALLOC) == 0,
931 ("Lost semaphore %d", semid));
932 sema[semid].u.sem_perm.key = key;
933 sema[semid].u.sem_perm.cuid = cred->cr_uid;
934 sema[semid].u.sem_perm.uid = cred->cr_uid;
935 sema[semid].u.sem_perm.cgid = cred->cr_gid;
936 sema[semid].u.sem_perm.gid = cred->cr_gid;
937 sema[semid].u.sem_perm.mode = (semflg & 0777) | SEM_ALLOC;
938 sema[semid].u.sem_perm.seq =
939 (sema[semid].u.sem_perm.seq + 1) & 0x7fff;
940 sema[semid].u.sem_nsems = nsems;
941 sema[semid].u.sem_otime = 0;
942 sema[semid].u.sem_ctime = time_second;
943 sema[semid].u.sem_base = &sem[semtot];
944 semtot += nsems;
945 bzero(sema[semid].u.sem_base,
946 sizeof(sema[semid].u.sem_base[0])*nsems);
947 #ifdef MAC
948 mac_sysvsem_create(cred, &sema[semid]);
949 #endif
950 mtx_unlock(&sema_mtx[semid]);
951 DPRINTF(("sembase = %p, next = %p\n",
952 sema[semid].u.sem_base, &sem[semtot]));
953 } else {
954 DPRINTF(("didn't find it and wasn't asked to create it\n"));
955 error = ENOENT;
956 goto done2;
957 }
958
959 found:
960 td->td_retval[0] = IXSEQ_TO_IPCID(semid, sema[semid].u.sem_perm);
961 done2:
962 mtx_unlock(&sem_mtx);
963 return (error);
964 }
965
966 #ifndef _SYS_SYSPROTO_H_
967 struct semop_args {
968 int semid;
969 struct sembuf *sops;
970 size_t nsops;
971 };
972 #endif
973 int
974 semop(struct thread *td, struct semop_args *uap)
975 {
976 #define SMALL_SOPS 8
977 struct sembuf small_sops[SMALL_SOPS];
978 int semid = uap->semid;
979 size_t nsops = uap->nsops;
980 struct sembuf *sops;
981 struct semid_kernel *semakptr;
982 struct sembuf *sopptr = 0;
983 struct sem *semptr = 0;
984 struct sem_undo *suptr;
985 struct mtx *sema_mtxp;
986 size_t i, j, k;
987 int error;
988 int do_wakeup, do_undos;
989 unsigned short seq;
990
991 #ifdef SEM_DEBUG
992 sops = NULL;
993 #endif
994 DPRINTF(("call to semop(%d, %p, %u)\n", semid, sops, nsops));
995
996 if (!prison_allow(td->td_ucred, PR_ALLOW_SYSVIPC))
997 return (ENOSYS);
998
999 semid = IPCID_TO_IX(semid); /* Convert back to zero origin */
1000
1001 if (semid < 0 || semid >= seminfo.semmni)
1002 return (EINVAL);
1003
1004 /* Allocate memory for sem_ops */
1005 if (nsops <= SMALL_SOPS)
1006 sops = small_sops;
1007 else if (nsops <= seminfo.semopm)
1008 sops = malloc(nsops * sizeof(*sops), M_TEMP, M_WAITOK);
1009 else {
1010 DPRINTF(("too many sops (max=%d, nsops=%d)\n", seminfo.semopm,
1011 nsops));
1012 return (E2BIG);
1013 }
1014 if ((error = copyin(uap->sops, sops, nsops * sizeof(sops[0]))) != 0) {
1015 DPRINTF(("error = %d from copyin(%p, %p, %d)\n", error,
1016 uap->sops, sops, nsops * sizeof(sops[0])));
1017 if (sops != small_sops)
1018 free(sops, M_SEM);
1019 return (error);
1020 }
1021
1022 semakptr = &sema[semid];
1023 sema_mtxp = &sema_mtx[semid];
1024 mtx_lock(sema_mtxp);
1025 if ((semakptr->u.sem_perm.mode & SEM_ALLOC) == 0) {
1026 error = EINVAL;
1027 goto done2;
1028 }
1029 seq = semakptr->u.sem_perm.seq;
1030 if (seq != IPCID_TO_SEQ(uap->semid)) {
1031 error = EINVAL;
1032 goto done2;
1033 }
1034 /*
1035 * Initial pass thru sops to see what permissions are needed.
1036 * Also perform any checks that don't need repeating on each
1037 * attempt to satisfy the request vector.
1038 */
1039 j = 0; /* permission needed */
1040 do_undos = 0;
1041 for (i = 0; i < nsops; i++) {
1042 sopptr = &sops[i];
1043 if (sopptr->sem_num >= semakptr->u.sem_nsems) {
1044 error = EFBIG;
1045 goto done2;
1046 }
1047 if (sopptr->sem_flg & SEM_UNDO && sopptr->sem_op != 0)
1048 do_undos = 1;
1049 j |= (sopptr->sem_op == 0) ? SEM_R : SEM_A;
1050 }
1051
1052 if ((error = ipcperm(td, &semakptr->u.sem_perm, j))) {
1053 DPRINTF(("error = %d from ipaccess\n", error));
1054 goto done2;
1055 }
1056 #ifdef MAC
1057 error = mac_sysvsem_check_semop(td->td_ucred, semakptr, j);
1058 if (error != 0)
1059 goto done2;
1060 #endif
1061
1062 /*
1063 * Loop trying to satisfy the vector of requests.
1064 * If we reach a point where we must wait, any requests already
1065 * performed are rolled back and we go to sleep until some other
1066 * process wakes us up. At this point, we start all over again.
1067 *
1068 * This ensures that from the perspective of other tasks, a set
1069 * of requests is atomic (never partially satisfied).
1070 */
1071 for (;;) {
1072 do_wakeup = 0;
1073 error = 0; /* error return if necessary */
1074
1075 for (i = 0; i < nsops; i++) {
1076 sopptr = &sops[i];
1077 semptr = &semakptr->u.sem_base[sopptr->sem_num];
1078
1079 DPRINTF((
1080 "semop: semakptr=%p, sem_base=%p, "
1081 "semptr=%p, sem[%d]=%d : op=%d, flag=%s\n",
1082 semakptr, semakptr->u.sem_base, semptr,
1083 sopptr->sem_num, semptr->semval, sopptr->sem_op,
1084 (sopptr->sem_flg & IPC_NOWAIT) ?
1085 "nowait" : "wait"));
1086
1087 if (sopptr->sem_op < 0) {
1088 if (semptr->semval + sopptr->sem_op < 0) {
1089 DPRINTF(("semop: can't do it now\n"));
1090 break;
1091 } else {
1092 semptr->semval += sopptr->sem_op;
1093 if (semptr->semval == 0 &&
1094 semptr->semzcnt > 0)
1095 do_wakeup = 1;
1096 }
1097 } else if (sopptr->sem_op == 0) {
1098 if (semptr->semval != 0) {
1099 DPRINTF(("semop: not zero now\n"));
1100 break;
1101 }
1102 } else if (semptr->semval + sopptr->sem_op >
1103 seminfo.semvmx) {
1104 error = ERANGE;
1105 break;
1106 } else {
1107 if (semptr->semncnt > 0)
1108 do_wakeup = 1;
1109 semptr->semval += sopptr->sem_op;
1110 }
1111 }
1112
1113 /*
1114 * Did we get through the entire vector?
1115 */
1116 if (i >= nsops)
1117 goto done;
1118
1119 /*
1120 * No ... rollback anything that we've already done
1121 */
1122 DPRINTF(("semop: rollback 0 through %d\n", i-1));
1123 for (j = 0; j < i; j++)
1124 semakptr->u.sem_base[sops[j].sem_num].semval -=
1125 sops[j].sem_op;
1126
1127 /* If we detected an error, return it */
1128 if (error != 0)
1129 goto done2;
1130
1131 /*
1132 * If the request that we couldn't satisfy has the
1133 * NOWAIT flag set then return with EAGAIN.
1134 */
1135 if (sopptr->sem_flg & IPC_NOWAIT) {
1136 error = EAGAIN;
1137 goto done2;
1138 }
1139
1140 if (sopptr->sem_op == 0)
1141 semptr->semzcnt++;
1142 else
1143 semptr->semncnt++;
1144
1145 DPRINTF(("semop: good night!\n"));
1146 error = msleep(semakptr, sema_mtxp, (PZERO - 4) | PCATCH,
1147 "semwait", 0);
1148 DPRINTF(("semop: good morning (error=%d)!\n", error));
1149 /* return code is checked below, after sem[nz]cnt-- */
1150
1151 /*
1152 * Make sure that the semaphore still exists
1153 */
1154 seq = semakptr->u.sem_perm.seq;
1155 if ((semakptr->u.sem_perm.mode & SEM_ALLOC) == 0 ||
1156 seq != IPCID_TO_SEQ(uap->semid)) {
1157 error = EIDRM;
1158 goto done2;
1159 }
1160
1161 /*
1162 * Renew the semaphore's pointer after wakeup since
1163 * during msleep sem_base may have been modified and semptr
1164 * is not valid any more
1165 */
1166 semptr = &semakptr->u.sem_base[sopptr->sem_num];
1167
1168 /*
1169 * The semaphore is still alive. Readjust the count of
1170 * waiting processes.
1171 */
1172 if (sopptr->sem_op == 0)
1173 semptr->semzcnt--;
1174 else
1175 semptr->semncnt--;
1176
1177 /*
1178 * Is it really morning, or was our sleep interrupted?
1179 * (Delayed check of msleep() return code because we
1180 * need to decrement sem[nz]cnt either way.)
1181 */
1182 if (error != 0) {
1183 error = EINTR;
1184 goto done2;
1185 }
1186 DPRINTF(("semop: good morning!\n"));
1187 }
1188
1189 done:
1190 /*
1191 * Process any SEM_UNDO requests.
1192 */
1193 if (do_undos) {
1194 SEMUNDO_LOCK();
1195 suptr = NULL;
1196 for (i = 0; i < nsops; i++) {
1197 /*
1198 * We only need to deal with SEM_UNDO's for non-zero
1199 * op's.
1200 */
1201 int adjval;
1202
1203 if ((sops[i].sem_flg & SEM_UNDO) == 0)
1204 continue;
1205 adjval = sops[i].sem_op;
1206 if (adjval == 0)
1207 continue;
1208 error = semundo_adjust(td, &suptr, semid, seq,
1209 sops[i].sem_num, -adjval);
1210 if (error == 0)
1211 continue;
1212
1213 /*
1214 * Oh-Oh! We ran out of either sem_undo's or undo's.
1215 * Rollback the adjustments to this point and then
1216 * rollback the semaphore ups and down so we can return
1217 * with an error with all structures restored. We
1218 * rollback the undo's in the exact reverse order that
1219 * we applied them. This guarantees that we won't run
1220 * out of space as we roll things back out.
1221 */
1222 for (j = 0; j < i; j++) {
1223 k = i - j - 1;
1224 if ((sops[k].sem_flg & SEM_UNDO) == 0)
1225 continue;
1226 adjval = sops[k].sem_op;
1227 if (adjval == 0)
1228 continue;
1229 if (semundo_adjust(td, &suptr, semid, seq,
1230 sops[k].sem_num, adjval) != 0)
1231 panic("semop - can't undo undos");
1232 }
1233
1234 for (j = 0; j < nsops; j++)
1235 semakptr->u.sem_base[sops[j].sem_num].semval -=
1236 sops[j].sem_op;
1237
1238 DPRINTF(("error = %d from semundo_adjust\n", error));
1239 SEMUNDO_UNLOCK();
1240 goto done2;
1241 } /* loop through the sops */
1242 SEMUNDO_UNLOCK();
1243 } /* if (do_undos) */
1244
1245 /* We're definitely done - set the sempid's and time */
1246 for (i = 0; i < nsops; i++) {
1247 sopptr = &sops[i];
1248 semptr = &semakptr->u.sem_base[sopptr->sem_num];
1249 semptr->sempid = td->td_proc->p_pid;
1250 }
1251 semakptr->u.sem_otime = time_second;
1252
1253 /*
1254 * Do a wakeup if any semaphore was up'd whilst something was
1255 * sleeping on it.
1256 */
1257 if (do_wakeup) {
1258 DPRINTF(("semop: doing wakeup\n"));
1259 wakeup(semakptr);
1260 DPRINTF(("semop: back from wakeup\n"));
1261 }
1262 DPRINTF(("semop: done\n"));
1263 td->td_retval[0] = 0;
1264 done2:
1265 mtx_unlock(sema_mtxp);
1266 if (sops != small_sops)
1267 free(sops, M_SEM);
1268 return (error);
1269 }
1270
1271 /*
1272 * Go through the undo structures for this process and apply the adjustments to
1273 * semaphores.
1274 */
1275 static void
1276 semexit_myhook(void *arg, struct proc *p)
1277 {
1278 struct sem_undo *suptr;
1279 struct semid_kernel *semakptr;
1280 struct mtx *sema_mtxp;
1281 int semid, semnum, adjval, ix;
1282 unsigned short seq;
1283
1284 /*
1285 * Go through the chain of undo vectors looking for one
1286 * associated with this process.
1287 */
1288 SEMUNDO_LOCK();
1289 LIST_FOREACH(suptr, &semu_list, un_next) {
1290 if (suptr->un_proc == p)
1291 break;
1292 }
1293 if (suptr == NULL) {
1294 SEMUNDO_UNLOCK();
1295 return;
1296 }
1297 LIST_REMOVE(suptr, un_next);
1298
1299 DPRINTF(("proc @%p has undo structure with %d entries\n", p,
1300 suptr->un_cnt));
1301
1302 /*
1303 * If there are any active undo elements then process them.
1304 */
1305 if (suptr->un_cnt > 0) {
1306 SEMUNDO_UNLOCK();
1307 for (ix = 0; ix < suptr->un_cnt; ix++) {
1308 semid = suptr->un_ent[ix].un_id;
1309 semnum = suptr->un_ent[ix].un_num;
1310 adjval = suptr->un_ent[ix].un_adjval;
1311 seq = suptr->un_ent[ix].un_seq;
1312 semakptr = &sema[semid];
1313 sema_mtxp = &sema_mtx[semid];
1314
1315 mtx_lock(sema_mtxp);
1316 if ((semakptr->u.sem_perm.mode & SEM_ALLOC) == 0 ||
1317 (semakptr->u.sem_perm.seq != seq)) {
1318 mtx_unlock(sema_mtxp);
1319 continue;
1320 }
1321 if (semnum >= semakptr->u.sem_nsems)
1322 panic("semexit - semnum out of range");
1323
1324 DPRINTF((
1325 "semexit: %p id=%d num=%d(adj=%d) ; sem=%d\n",
1326 suptr->un_proc, suptr->un_ent[ix].un_id,
1327 suptr->un_ent[ix].un_num,
1328 suptr->un_ent[ix].un_adjval,
1329 semakptr->u.sem_base[semnum].semval));
1330
1331 if (adjval < 0 && semakptr->u.sem_base[semnum].semval <
1332 -adjval)
1333 semakptr->u.sem_base[semnum].semval = 0;
1334 else
1335 semakptr->u.sem_base[semnum].semval += adjval;
1336
1337 wakeup(semakptr);
1338 DPRINTF(("semexit: back from wakeup\n"));
1339 mtx_unlock(sema_mtxp);
1340 }
1341 SEMUNDO_LOCK();
1342 }
1343
1344 /*
1345 * Deallocate the undo vector.
1346 */
1347 DPRINTF(("removing vector\n"));
1348 suptr->un_proc = NULL;
1349 suptr->un_cnt = 0;
1350 LIST_INSERT_HEAD(&semu_free_list, suptr, un_next);
1351 SEMUNDO_UNLOCK();
1352 }
1353
1354 static int
1355 sysctl_sema(SYSCTL_HANDLER_ARGS)
1356 {
1357
1358 return (SYSCTL_OUT(req, sema,
1359 sizeof(struct semid_kernel) * seminfo.semmni));
1360 }
1361
1362 #if defined(COMPAT_FREEBSD4) || defined(COMPAT_FREEBSD5) || \
1363 defined(COMPAT_FREEBSD6) || defined(COMPAT_FREEBSD7)
1364
1365 /* XXX casting to (sy_call_t *) is bogus, as usual. */
1366 static sy_call_t *semcalls[] = {
1367 (sy_call_t *)freebsd7___semctl, (sy_call_t *)semget,
1368 (sy_call_t *)semop
1369 };
1370
1371 /*
1372 * Entry point for all SEM calls.
1373 */
1374 int
1375 semsys(td, uap)
1376 struct thread *td;
1377 /* XXX actually varargs. */
1378 struct semsys_args /* {
1379 int which;
1380 int a2;
1381 int a3;
1382 int a4;
1383 int a5;
1384 } */ *uap;
1385 {
1386 int error;
1387
1388 if (!prison_allow(td->td_ucred, PR_ALLOW_SYSVIPC))
1389 return (ENOSYS);
1390 if (uap->which < 0 ||
1391 uap->which >= sizeof(semcalls)/sizeof(semcalls[0]))
1392 return (EINVAL);
1393 error = (*semcalls[uap->which])(td, &uap->a2);
1394 return (error);
1395 }
1396
1397 #ifndef CP
1398 #define CP(src, dst, fld) do { (dst).fld = (src).fld; } while (0)
1399 #endif
1400
1401 #ifndef _SYS_SYSPROTO_H_
1402 struct freebsd7___semctl_args {
1403 int semid;
1404 int semnum;
1405 int cmd;
1406 union semun_old *arg;
1407 };
1408 #endif
1409 int
1410 freebsd7___semctl(struct thread *td, struct freebsd7___semctl_args *uap)
1411 {
1412 struct semid_ds_old dsold;
1413 struct semid_ds dsbuf;
1414 union semun_old arg;
1415 union semun semun;
1416 register_t rval;
1417 int error;
1418
1419 switch (uap->cmd) {
1420 case SEM_STAT:
1421 case IPC_SET:
1422 case IPC_STAT:
1423 case GETALL:
1424 case SETVAL:
1425 case SETALL:
1426 error = copyin(uap->arg, &arg, sizeof(arg));
1427 if (error)
1428 return (error);
1429 break;
1430 }
1431
1432 switch (uap->cmd) {
1433 case SEM_STAT:
1434 case IPC_STAT:
1435 semun.buf = &dsbuf;
1436 break;
1437 case IPC_SET:
1438 error = copyin(arg.buf, &dsold, sizeof(dsold));
1439 if (error)
1440 return (error);
1441 ipcperm_old2new(&dsold.sem_perm, &dsbuf.sem_perm);
1442 CP(dsold, dsbuf, sem_base);
1443 CP(dsold, dsbuf, sem_nsems);
1444 CP(dsold, dsbuf, sem_otime);
1445 CP(dsold, dsbuf, sem_ctime);
1446 semun.buf = &dsbuf;
1447 break;
1448 case GETALL:
1449 case SETALL:
1450 semun.array = arg.array;
1451 break;
1452 case SETVAL:
1453 semun.val = arg.val;
1454 break;
1455 }
1456
1457 error = kern_semctl(td, uap->semid, uap->semnum, uap->cmd, &semun,
1458 &rval);
1459 if (error)
1460 return (error);
1461
1462 switch (uap->cmd) {
1463 case SEM_STAT:
1464 case IPC_STAT:
1465 bzero(&dsold, sizeof(dsold));
1466 ipcperm_new2old(&dsbuf.sem_perm, &dsold.sem_perm);
1467 CP(dsbuf, dsold, sem_base);
1468 CP(dsbuf, dsold, sem_nsems);
1469 CP(dsbuf, dsold, sem_otime);
1470 CP(dsbuf, dsold, sem_ctime);
1471 error = copyout(&dsold, arg.buf, sizeof(dsold));
1472 break;
1473 }
1474
1475 if (error == 0)
1476 td->td_retval[0] = rval;
1477 return (error);
1478 }
1479
1480 #endif /* COMPAT_FREEBSD{4,5,6,7} */
1481
1482 #ifdef COMPAT_FREEBSD32
1483
1484 int
1485 freebsd32_semsys(struct thread *td, struct freebsd32_semsys_args *uap)
1486 {
1487
1488 #if defined(COMPAT_FREEBSD4) || defined(COMPAT_FREEBSD5) || \
1489 defined(COMPAT_FREEBSD6) || defined(COMPAT_FREEBSD7)
1490 switch (uap->which) {
1491 case 0:
1492 return (freebsd7_freebsd32_semctl(td,
1493 (struct freebsd7_freebsd32_semctl_args *)&uap->a2));
1494 default:
1495 return (semsys(td, (struct semsys_args *)uap));
1496 }
1497 #else
1498 return (nosys(td, NULL));
1499 #endif
1500 }
1501
1502 #if defined(COMPAT_FREEBSD4) || defined(COMPAT_FREEBSD5) || \
1503 defined(COMPAT_FREEBSD6) || defined(COMPAT_FREEBSD7)
1504 int
1505 freebsd7_freebsd32_semctl(struct thread *td,
1506 struct freebsd7_freebsd32_semctl_args *uap)
1507 {
1508 struct semid_ds32_old dsbuf32;
1509 struct semid_ds dsbuf;
1510 union semun semun;
1511 union semun32 arg;
1512 register_t rval;
1513 int error;
1514
1515 switch (uap->cmd) {
1516 case SEM_STAT:
1517 case IPC_SET:
1518 case IPC_STAT:
1519 case GETALL:
1520 case SETVAL:
1521 case SETALL:
1522 error = copyin(uap->arg, &arg, sizeof(arg));
1523 if (error)
1524 return (error);
1525 break;
1526 }
1527
1528 switch (uap->cmd) {
1529 case SEM_STAT:
1530 case IPC_STAT:
1531 semun.buf = &dsbuf;
1532 break;
1533 case IPC_SET:
1534 error = copyin(PTRIN(arg.buf), &dsbuf32, sizeof(dsbuf32));
1535 if (error)
1536 return (error);
1537 freebsd32_ipcperm_old_in(&dsbuf32.sem_perm, &dsbuf.sem_perm);
1538 PTRIN_CP(dsbuf32, dsbuf, sem_base);
1539 CP(dsbuf32, dsbuf, sem_nsems);
1540 CP(dsbuf32, dsbuf, sem_otime);
1541 CP(dsbuf32, dsbuf, sem_ctime);
1542 semun.buf = &dsbuf;
1543 break;
1544 case GETALL:
1545 case SETALL:
1546 semun.array = PTRIN(arg.array);
1547 break;
1548 case SETVAL:
1549 semun.val = arg.val;
1550 break;
1551 }
1552
1553 error = kern_semctl(td, uap->semid, uap->semnum, uap->cmd, &semun,
1554 &rval);
1555 if (error)
1556 return (error);
1557
1558 switch (uap->cmd) {
1559 case SEM_STAT:
1560 case IPC_STAT:
1561 bzero(&dsbuf32, sizeof(dsbuf32));
1562 freebsd32_ipcperm_old_out(&dsbuf.sem_perm, &dsbuf32.sem_perm);
1563 PTROUT_CP(dsbuf, dsbuf32, sem_base);
1564 CP(dsbuf, dsbuf32, sem_nsems);
1565 CP(dsbuf, dsbuf32, sem_otime);
1566 CP(dsbuf, dsbuf32, sem_ctime);
1567 error = copyout(&dsbuf32, PTRIN(arg.buf), sizeof(dsbuf32));
1568 break;
1569 }
1570
1571 if (error == 0)
1572 td->td_retval[0] = rval;
1573 return (error);
1574 }
1575 #endif
1576
1577 int
1578 freebsd32_semctl(struct thread *td, struct freebsd32_semctl_args *uap)
1579 {
1580 struct semid_ds32 dsbuf32;
1581 struct semid_ds dsbuf;
1582 union semun semun;
1583 union semun32 arg;
1584 register_t rval;
1585 int error;
1586
1587 switch (uap->cmd) {
1588 case SEM_STAT:
1589 case IPC_SET:
1590 case IPC_STAT:
1591 case GETALL:
1592 case SETVAL:
1593 case SETALL:
1594 error = copyin(uap->arg, &arg, sizeof(arg));
1595 if (error)
1596 return (error);
1597 break;
1598 }
1599
1600 switch (uap->cmd) {
1601 case SEM_STAT:
1602 case IPC_STAT:
1603 semun.buf = &dsbuf;
1604 break;
1605 case IPC_SET:
1606 error = copyin(PTRIN(arg.buf), &dsbuf32, sizeof(dsbuf32));
1607 if (error)
1608 return (error);
1609 freebsd32_ipcperm_in(&dsbuf32.sem_perm, &dsbuf.sem_perm);
1610 PTRIN_CP(dsbuf32, dsbuf, sem_base);
1611 CP(dsbuf32, dsbuf, sem_nsems);
1612 CP(dsbuf32, dsbuf, sem_otime);
1613 CP(dsbuf32, dsbuf, sem_ctime);
1614 semun.buf = &dsbuf;
1615 break;
1616 case GETALL:
1617 case SETALL:
1618 semun.array = PTRIN(arg.array);
1619 break;
1620 case SETVAL:
1621 semun.val = arg.val;
1622 break;
1623 }
1624
1625 error = kern_semctl(td, uap->semid, uap->semnum, uap->cmd, &semun,
1626 &rval);
1627 if (error)
1628 return (error);
1629
1630 switch (uap->cmd) {
1631 case SEM_STAT:
1632 case IPC_STAT:
1633 bzero(&dsbuf32, sizeof(dsbuf32));
1634 freebsd32_ipcperm_out(&dsbuf.sem_perm, &dsbuf32.sem_perm);
1635 PTROUT_CP(dsbuf, dsbuf32, sem_base);
1636 CP(dsbuf, dsbuf32, sem_nsems);
1637 CP(dsbuf, dsbuf32, sem_otime);
1638 CP(dsbuf, dsbuf32, sem_ctime);
1639 error = copyout(&dsbuf32, PTRIN(arg.buf), sizeof(dsbuf32));
1640 break;
1641 }
1642
1643 if (error == 0)
1644 td->td_retval[0] = rval;
1645 return (error);
1646 }
1647
1648 #endif /* COMPAT_FREEBSD32 */
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