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/racct.h>
55#include <sys/sem.h>
56#include <sys/syscall.h>
57#include <sys/syscallsubr.h>
58#include <sys/sysent.h>
59#include <sys/sysctl.h>
60#include <sys/uio.h>
61#include <sys/malloc.h>
62#include <sys/jail.h>
63
64#include <security/mac/mac_framework.h>
65
66FEATURE(sysv_sem, "System V semaphores support");
67
68static MALLOC_DEFINE(M_SEM, "sem", "SVID compatible semaphores");
69
70#ifdef SEM_DEBUG
71#define DPRINTF(a) printf a
72#else
73#define DPRINTF(a)
74#endif
75
76static int seminit(void);
77static int sysvsem_modload(struct module *, int, void *);
78static int semunload(void);
79static void semexit_myhook(void *arg, struct proc *p);
80static int sysctl_sema(SYSCTL_HANDLER_ARGS);
81static int semvalid(int semid, struct semid_kernel *semakptr);
82
83#ifndef _SYS_SYSPROTO_H_
84struct __semctl_args;
85int __semctl(struct thread *td, struct __semctl_args *uap);
86struct semget_args;
87int semget(struct thread *td, struct semget_args *uap);
88struct semop_args;
89int semop(struct thread *td, struct semop_args *uap);
90#endif
91
92static struct sem_undo *semu_alloc(struct thread *td);
93static int semundo_adjust(struct thread *td, struct sem_undo **supptr,
94 int semid, int semseq, int semnum, int adjval);
95static void semundo_clear(int semid, int semnum);
96
97static struct mtx sem_mtx; /* semaphore global lock */
98static struct mtx sem_undo_mtx;
99static int semtot = 0;
100static struct semid_kernel *sema; /* semaphore id pool */
101static struct mtx *sema_mtx; /* semaphore id pool mutexes*/
102static struct sem *sem; /* semaphore pool */
103LIST_HEAD(, sem_undo) semu_list; /* list of active undo structures */
104LIST_HEAD(, sem_undo) semu_free_list; /* list of free undo structures */
105static int *semu; /* undo structure pool */
106static eventhandler_tag semexit_tag;
107
108#define SEMUNDO_MTX sem_undo_mtx
109#define SEMUNDO_LOCK() mtx_lock(&SEMUNDO_MTX);
110#define SEMUNDO_UNLOCK() mtx_unlock(&SEMUNDO_MTX);
111#define SEMUNDO_LOCKASSERT(how) mtx_assert(&SEMUNDO_MTX, (how));
112
113struct sem {
114 u_short semval; /* semaphore value */
115 pid_t sempid; /* pid of last operation */
116 u_short semncnt; /* # awaiting semval > cval */
117 u_short semzcnt; /* # awaiting semval = 0 */
118};
119
120/*
121 * Undo structure (one per process)
122 */
123struct sem_undo {
124 LIST_ENTRY(sem_undo) un_next; /* ptr to next active undo structure */
125 struct proc *un_proc; /* owner of this structure */
126 short un_cnt; /* # of active entries */
127 struct undo {
128 short un_adjval; /* adjust on exit values */
129 short un_num; /* semaphore # */
130 int un_id; /* semid */
131 unsigned short un_seq;
132 } un_ent[1]; /* undo entries */
133};
134
135/*
136 * Configuration parameters
137 */
138#ifndef SEMMNI
139#define SEMMNI 50 /* # of semaphore identifiers */
140#endif
141#ifndef SEMMNS
142#define SEMMNS 340 /* # of semaphores in system */
143#endif
144#ifndef SEMUME
145#define SEMUME 50 /* max # of undo entries per process */
146#endif
147#ifndef SEMMNU
148#define SEMMNU 150 /* # of undo structures in system */
149#endif
150
151/* shouldn't need tuning */
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 */
181struct seminfo seminfo = {
182 SEMMNI, /* # of semaphore identifiers */
183 SEMMNS, /* # of semaphores in system */
184 SEMMNU, /* # of undo structures in system */
185 SEMMSL, /* max # of semaphores per id */
186 SEMOPM, /* max # of operations per semop call */
187 SEMUME, /* max # of undo entries per process */
188 SEMUSZ, /* size in bytes of undo structure */
189 SEMVMX, /* semaphore maximum value */
190 SEMAEM /* adjust on exit max value */
191};
192
193SYSCTL_INT(_kern_ipc, OID_AUTO, semmni, CTLFLAG_RDTUN, &seminfo.semmni, 0,
194 "Number of semaphore identifiers");
195SYSCTL_INT(_kern_ipc, OID_AUTO, semmns, CTLFLAG_RDTUN, &seminfo.semmns, 0,
196 "Maximum number of semaphores in the system");
197SYSCTL_INT(_kern_ipc, OID_AUTO, semmnu, CTLFLAG_RDTUN, &seminfo.semmnu, 0,
198 "Maximum number of undo structures in the system");
199SYSCTL_INT(_kern_ipc, OID_AUTO, semmsl, CTLFLAG_RWTUN, &seminfo.semmsl, 0,
200 "Max semaphores per id");
201SYSCTL_INT(_kern_ipc, OID_AUTO, semopm, CTLFLAG_RDTUN, &seminfo.semopm, 0,
202 "Max operations per semop call");
203SYSCTL_INT(_kern_ipc, OID_AUTO, semume, CTLFLAG_RDTUN, &seminfo.semume, 0,
204 "Max undo entries per process");
205SYSCTL_INT(_kern_ipc, OID_AUTO, semusz, CTLFLAG_RDTUN, &seminfo.semusz, 0,
206 "Size in bytes of undo structure");
207SYSCTL_INT(_kern_ipc, OID_AUTO, semvmx, CTLFLAG_RWTUN, &seminfo.semvmx, 0,
208 "Semaphore maximum value");
209SYSCTL_INT(_kern_ipc, OID_AUTO, semaem, CTLFLAG_RWTUN, &seminfo.semaem, 0,
210 "Adjust on exit max value");
211SYSCTL_PROC(_kern_ipc, OID_AUTO, sema, CTLTYPE_OPAQUE | CTLFLAG_RD,
212 NULL, 0, sysctl_sema, "", "Semaphore id pool");
213
214static struct syscall_helper_data sem_syscalls[] = {
215 SYSCALL_INIT_HELPER(__semctl),
216 SYSCALL_INIT_HELPER(semget),
217 SYSCALL_INIT_HELPER(semop),
218#if defined(COMPAT_FREEBSD4) || defined(COMPAT_FREEBSD5) || \
219 defined(COMPAT_FREEBSD6) || defined(COMPAT_FREEBSD7)
220 SYSCALL_INIT_HELPER(semsys),
221 SYSCALL_INIT_HELPER_COMPAT(freebsd7___semctl),
222#endif
223 SYSCALL_INIT_LAST
224};
225
226#ifdef COMPAT_FREEBSD32
227#include <compat/freebsd32/freebsd32.h>
228#include <compat/freebsd32/freebsd32_ipc.h>
229#include <compat/freebsd32/freebsd32_proto.h>
230#include <compat/freebsd32/freebsd32_signal.h>
231#include <compat/freebsd32/freebsd32_syscall.h>
232#include <compat/freebsd32/freebsd32_util.h>
233
234static struct syscall_helper_data sem32_syscalls[] = {
235 SYSCALL32_INIT_HELPER(freebsd32_semctl),
236 SYSCALL32_INIT_HELPER_COMPAT(semget),
237 SYSCALL32_INIT_HELPER_COMPAT(semop),
238 SYSCALL32_INIT_HELPER(freebsd32_semsys),
239#if defined(COMPAT_FREEBSD4) || defined(COMPAT_FREEBSD5) || \
240 defined(COMPAT_FREEBSD6) || defined(COMPAT_FREEBSD7)
241 SYSCALL32_INIT_HELPER(freebsd7_freebsd32_semctl),
242#endif
243 SYSCALL_INIT_LAST
244};
245#endif
246
247static int
248seminit(void)
249{
250 int i, error;
251
252 sem = malloc(sizeof(struct sem) * seminfo.semmns, M_SEM, M_WAITOK);
253 sema = malloc(sizeof(struct semid_kernel) * seminfo.semmni, M_SEM,
254 M_WAITOK);
255 sema_mtx = malloc(sizeof(struct mtx) * seminfo.semmni, M_SEM,
256 M_WAITOK | M_ZERO);
257 semu = malloc(seminfo.semmnu * seminfo.semusz, M_SEM, M_WAITOK);
258
259 for (i = 0; i < seminfo.semmni; i++) {
260 sema[i].u.sem_base = 0;
261 sema[i].u.sem_perm.mode = 0;
262 sema[i].u.sem_perm.seq = 0;
263#ifdef MAC
264 mac_sysvsem_init(&sema[i]);
265#endif
266 }
267 for (i = 0; i < seminfo.semmni; i++)
268 mtx_init(&sema_mtx[i], "semid", NULL, MTX_DEF);
269 LIST_INIT(&semu_free_list);
270 for (i = 0; i < seminfo.semmnu; i++) {
271 struct sem_undo *suptr = SEMU(i);
272 suptr->un_proc = NULL;
273 LIST_INSERT_HEAD(&semu_free_list, suptr, un_next);
274 }
275 LIST_INIT(&semu_list);
276 mtx_init(&sem_mtx, "sem", NULL, MTX_DEF);
277 mtx_init(&sem_undo_mtx, "semu", NULL, MTX_DEF);
278 semexit_tag = EVENTHANDLER_REGISTER(process_exit, semexit_myhook, NULL,
279 EVENTHANDLER_PRI_ANY);
280
281 error = syscall_helper_register(sem_syscalls, SY_THR_STATIC_KLD);
282 if (error != 0)
283 return (error);
284#ifdef COMPAT_FREEBSD32
285 error = syscall32_helper_register(sem32_syscalls, SY_THR_STATIC_KLD);
286 if (error != 0)
287 return (error);
288#endif
289 return (0);
290}
291
292static int
293semunload(void)
294{
295 int i;
296
297 /* XXXKIB */
298 if (semtot != 0)
299 return (EBUSY);
300
301#ifdef COMPAT_FREEBSD32
302 syscall32_helper_unregister(sem32_syscalls);
303#endif
304 syscall_helper_unregister(sem_syscalls);
305 EVENTHANDLER_DEREGISTER(process_exit, semexit_tag);
306#ifdef MAC
307 for (i = 0; i < seminfo.semmni; i++)
308 mac_sysvsem_destroy(&sema[i]);
309#endif
310 free(sem, M_SEM);
311 free(sema, M_SEM);
312 free(semu, M_SEM);
313 for (i = 0; i < seminfo.semmni; i++)
314 mtx_destroy(&sema_mtx[i]);
315 free(sema_mtx, M_SEM);
316 mtx_destroy(&sem_mtx);
317 mtx_destroy(&sem_undo_mtx);
318 return (0);
319}
320
321static int
322sysvsem_modload(struct module *module, int cmd, void *arg)
323{
324 int error = 0;
325
326 switch (cmd) {
327 case MOD_LOAD:
328 error = seminit();
329 if (error != 0)
330 semunload();
331 break;
332 case MOD_UNLOAD:
333 error = semunload();
334 break;
335 case MOD_SHUTDOWN:
336 break;
337 default:
338 error = EINVAL;
339 break;
340 }
341 return (error);
342}
343
344static moduledata_t sysvsem_mod = {
345 "sysvsem",
346 &sysvsem_modload,
347 NULL
348};
349
350DECLARE_MODULE(sysvsem, sysvsem_mod, SI_SUB_SYSV_SEM, SI_ORDER_FIRST);
351MODULE_VERSION(sysvsem, 1);
352
353/*
354 * Allocate a new sem_undo structure for a process
355 * (returns ptr to structure or NULL if no more room)
356 */
357
358static struct sem_undo *
359semu_alloc(struct thread *td)
360{
361 struct sem_undo *suptr;
362
363 SEMUNDO_LOCKASSERT(MA_OWNED);
364 if ((suptr = LIST_FIRST(&semu_free_list)) == NULL)
365 return (NULL);
366 LIST_REMOVE(suptr, un_next);
367 LIST_INSERT_HEAD(&semu_list, suptr, un_next);
368 suptr->un_cnt = 0;
369 suptr->un_proc = td->td_proc;
370 return (suptr);
371}
372
373static int
374semu_try_free(struct sem_undo *suptr)
375{
376
377 SEMUNDO_LOCKASSERT(MA_OWNED);
378
379 if (suptr->un_cnt != 0)
380 return (0);
381 LIST_REMOVE(suptr, un_next);
382 LIST_INSERT_HEAD(&semu_free_list, suptr, un_next);
383 return (1);
384}
385
386/*
387 * Adjust a particular entry for a particular proc
388 */
389
390static int
391semundo_adjust(struct thread *td, struct sem_undo **supptr, int semid,
392 int semseq, int semnum, int adjval)
393{
394 struct proc *p = td->td_proc;
395 struct sem_undo *suptr;
396 struct undo *sunptr;
397 int i;
398
399 SEMUNDO_LOCKASSERT(MA_OWNED);
400 /* Look for and remember the sem_undo if the caller doesn't provide
401 it */
402
403 suptr = *supptr;
404 if (suptr == NULL) {
405 LIST_FOREACH(suptr, &semu_list, un_next) {
406 if (suptr->un_proc == p) {
407 *supptr = suptr;
408 break;
409 }
410 }
411 if (suptr == NULL) {
412 if (adjval == 0)
413 return(0);
414 suptr = semu_alloc(td);
415 if (suptr == NULL)
416 return (ENOSPC);
417 *supptr = suptr;
418 }
419 }
420
421 /*
422 * Look for the requested entry and adjust it (delete if adjval becomes
423 * 0).
424 */
425 sunptr = &suptr->un_ent[0];
426 for (i = 0; i < suptr->un_cnt; i++, sunptr++) {
427 if (sunptr->un_id != semid || sunptr->un_num != semnum)
428 continue;
429 if (adjval != 0) {
430 adjval += sunptr->un_adjval;
431 if (adjval > seminfo.semaem || adjval < -seminfo.semaem)
432 return (ERANGE);
433 }
434 sunptr->un_adjval = adjval;
435 if (sunptr->un_adjval == 0) {
436 suptr->un_cnt--;
437 if (i < suptr->un_cnt)
438 suptr->un_ent[i] =
439 suptr->un_ent[suptr->un_cnt];
440 if (suptr->un_cnt == 0)
441 semu_try_free(suptr);
442 }
443 return (0);
444 }
445
446 /* Didn't find the right entry - create it */
447 if (adjval == 0)
448 return (0);
449 if (adjval > seminfo.semaem || adjval < -seminfo.semaem)
450 return (ERANGE);
451 if (suptr->un_cnt != seminfo.semume) {
452 sunptr = &suptr->un_ent[suptr->un_cnt];
453 suptr->un_cnt++;
454 sunptr->un_adjval = adjval;
455 sunptr->un_id = semid;
456 sunptr->un_num = semnum;
457 sunptr->un_seq = semseq;
458 } else
459 return (EINVAL);
460 return (0);
461}
462
463static void
464semundo_clear(int semid, int semnum)
465{
466 struct sem_undo *suptr, *suptr1;
467 struct undo *sunptr;
468 int i;
469
470 SEMUNDO_LOCKASSERT(MA_OWNED);
471 LIST_FOREACH_SAFE(suptr, &semu_list, un_next, suptr1) {
472 sunptr = &suptr->un_ent[0];
473 for (i = 0; i < suptr->un_cnt; i++, sunptr++) {
474 if (sunptr->un_id != semid)
475 continue;
476 if (semnum == -1 || sunptr->un_num == semnum) {
477 suptr->un_cnt--;
478 if (i < suptr->un_cnt) {
479 suptr->un_ent[i] =
480 suptr->un_ent[suptr->un_cnt];
481 continue;
482 }
483 semu_try_free(suptr);
484 }
485 if (semnum != -1)
486 break;
487 }
488 }
489}
490
491static int
492semvalid(int semid, struct semid_kernel *semakptr)
493{
494
495 return ((semakptr->u.sem_perm.mode & SEM_ALLOC) == 0 ||
496 semakptr->u.sem_perm.seq != IPCID_TO_SEQ(semid) ? EINVAL : 0);
497}
498
499/*
500 * Note that the user-mode half of this passes a union, not a pointer.
501 */
502#ifndef _SYS_SYSPROTO_H_
503struct __semctl_args {
504 int semid;
505 int semnum;
506 int cmd;
507 union semun *arg;
508};
509#endif
510int
511sys___semctl(struct thread *td, struct __semctl_args *uap)
512{
513 struct semid_ds dsbuf;
514 union semun arg, semun;
515 register_t rval;
516 int error;
517
518 switch (uap->cmd) {
519 case SEM_STAT:
520 case IPC_SET:
521 case IPC_STAT:
522 case GETALL:
523 case SETVAL:
524 case SETALL:
525 error = copyin(uap->arg, &arg, sizeof(arg));
526 if (error)
527 return (error);
528 break;
529 }
530
531 switch (uap->cmd) {
532 case SEM_STAT:
533 case IPC_STAT:
534 semun.buf = &dsbuf;
535 break;
536 case IPC_SET:
537 error = copyin(arg.buf, &dsbuf, sizeof(dsbuf));
538 if (error)
539 return (error);
540 semun.buf = &dsbuf;
541 break;
542 case GETALL:
543 case SETALL:
544 semun.array = arg.array;
545 break;
546 case SETVAL:
547 semun.val = arg.val;
548 break;
549 }
550
551 error = kern_semctl(td, uap->semid, uap->semnum, uap->cmd, &semun,
552 &rval);
553 if (error)
554 return (error);
555
556 switch (uap->cmd) {
557 case SEM_STAT:
558 case IPC_STAT:
559 error = copyout(&dsbuf, arg.buf, sizeof(dsbuf));
560 break;
561 }
562
563 if (error == 0)
564 td->td_retval[0] = rval;
565 return (error);
566}
567
568int
569kern_semctl(struct thread *td, int semid, int semnum, int cmd,
570 union semun *arg, register_t *rval)
571{
572 u_short *array;
573 struct ucred *cred = td->td_ucred;
574 int i, error;
575 struct semid_ds *sbuf;
576 struct semid_kernel *semakptr;
577 struct mtx *sema_mtxp;
578 u_short usval, count;
579 int semidx;
580
581 DPRINTF(("call to semctl(%d, %d, %d, 0x%p)\n",
582 semid, semnum, cmd, arg));
583 if (!prison_allow(td->td_ucred, PR_ALLOW_SYSVIPC))
584 return (ENOSYS);
585
586 array = NULL;
587
588 switch(cmd) {
589 case SEM_STAT:
590 /*
591 * For this command we assume semid is an array index
592 * rather than an IPC id.
593 */
594 if (semid < 0 || semid >= seminfo.semmni)
595 return (EINVAL);
596 semakptr = &sema[semid];
597 sema_mtxp = &sema_mtx[semid];
598 mtx_lock(sema_mtxp);
599 if ((semakptr->u.sem_perm.mode & SEM_ALLOC) == 0) {
600 error = EINVAL;
601 goto done2;
602 }
603 if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_R)))
604 goto done2;
605#ifdef MAC
606 error = mac_sysvsem_check_semctl(cred, semakptr, cmd);
607 if (error != 0)
608 goto done2;
609#endif
610 bcopy(&semakptr->u, arg->buf, sizeof(struct semid_ds));
611 *rval = IXSEQ_TO_IPCID(semid, semakptr->u.sem_perm);
612 mtx_unlock(sema_mtxp);
613 return (0);
614 }
615
616 semidx = IPCID_TO_IX(semid);
617 if (semidx < 0 || semidx >= seminfo.semmni)
618 return (EINVAL);
619
620 semakptr = &sema[semidx];
621 sema_mtxp = &sema_mtx[semidx];
622 if (cmd == IPC_RMID)
623 mtx_lock(&sem_mtx);
624 mtx_lock(sema_mtxp);
625#ifdef MAC
626 error = mac_sysvsem_check_semctl(cred, semakptr, cmd);
627 if (error != 0)
628 goto done2;
629#endif
630
631 error = 0;
632 *rval = 0;
633
634 switch (cmd) {
635 case IPC_RMID:
636 if ((error = semvalid(semid, semakptr)) != 0)
637 goto done2;
638 if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_M)))
639 goto done2;
640 semakptr->u.sem_perm.cuid = cred->cr_uid;
641 semakptr->u.sem_perm.uid = cred->cr_uid;
642 semakptr->u.sem_perm.mode = 0;
643 racct_sub_cred(semakptr->cred, RACCT_NSEM, semakptr->u.sem_nsems);
644 crfree(semakptr->cred);
645 semakptr->cred = NULL;
646 SEMUNDO_LOCK();
647 semundo_clear(semidx, -1);
648 SEMUNDO_UNLOCK();
649#ifdef MAC
650 mac_sysvsem_cleanup(semakptr);
651#endif
652 wakeup(semakptr);
653 for (i = 0; i < seminfo.semmni; i++) {
654 if ((sema[i].u.sem_perm.mode & SEM_ALLOC) &&
655 sema[i].u.sem_base > semakptr->u.sem_base)
656 mtx_lock_flags(&sema_mtx[i], LOP_DUPOK);
657 }
658 for (i = semakptr->u.sem_base - sem; i < semtot; i++)
659 sem[i] = sem[i + semakptr->u.sem_nsems];
660 for (i = 0; i < seminfo.semmni; i++) {
661 if ((sema[i].u.sem_perm.mode & SEM_ALLOC) &&
662 sema[i].u.sem_base > semakptr->u.sem_base) {
663 sema[i].u.sem_base -= semakptr->u.sem_nsems;
664 mtx_unlock(&sema_mtx[i]);
665 }
666 }
667 semtot -= semakptr->u.sem_nsems;
668 break;
669
670 case IPC_SET:
671 if ((error = semvalid(semid, semakptr)) != 0)
672 goto done2;
673 if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_M)))
674 goto done2;
675 sbuf = arg->buf;
676 semakptr->u.sem_perm.uid = sbuf->sem_perm.uid;
677 semakptr->u.sem_perm.gid = sbuf->sem_perm.gid;
678 semakptr->u.sem_perm.mode = (semakptr->u.sem_perm.mode &
679 ~0777) | (sbuf->sem_perm.mode & 0777);
680 semakptr->u.sem_ctime = time_second;
681 break;
682
683 case IPC_STAT:
684 if ((error = semvalid(semid, semakptr)) != 0)
685 goto done2;
686 if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_R)))
687 goto done2;
688 bcopy(&semakptr->u, arg->buf, sizeof(struct semid_ds));
689 break;
690
691 case GETNCNT:
692 if ((error = semvalid(semid, semakptr)) != 0)
693 goto done2;
694 if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_R)))
695 goto done2;
696 if (semnum < 0 || semnum >= semakptr->u.sem_nsems) {
697 error = EINVAL;
698 goto done2;
699 }
700 *rval = semakptr->u.sem_base[semnum].semncnt;
701 break;
702
703 case GETPID:
704 if ((error = semvalid(semid, semakptr)) != 0)
705 goto done2;
706 if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_R)))
707 goto done2;
708 if (semnum < 0 || semnum >= semakptr->u.sem_nsems) {
709 error = EINVAL;
710 goto done2;
711 }
712 *rval = semakptr->u.sem_base[semnum].sempid;
713 break;
714
715 case GETVAL:
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].semval;
725 break;
726
727 case GETALL:
728 /*
729 * Unfortunately, callers of this function don't know
730 * in advance how many semaphores are in this set.
731 * While we could just allocate the maximum size array
732 * and pass the actual size back to the caller, that
733 * won't work for SETALL since we can't copyin() more
734 * data than the user specified as we may return a
735 * spurious EFAULT.
736 *
737 * Note that the number of semaphores in a set is
738 * fixed for the life of that set. The only way that
739 * the 'count' could change while are blocked in
740 * malloc() is if this semaphore set were destroyed
741 * and a new one created with the same index.
742 * However, semvalid() will catch that due to the
743 * sequence number unless exactly 0x8000 (or a
744 * multiple thereof) semaphore sets for the same index
745 * are created and destroyed while we are in malloc!
746 *
747 */
748 count = semakptr->u.sem_nsems;
749 mtx_unlock(sema_mtxp);
750 array = malloc(sizeof(*array) * count, M_TEMP, M_WAITOK);
751 mtx_lock(sema_mtxp);
752 if ((error = semvalid(semid, semakptr)) != 0)
753 goto done2;
754 KASSERT(count == semakptr->u.sem_nsems, ("nsems changed"));
755 if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_R)))
756 goto done2;
757 for (i = 0; i < semakptr->u.sem_nsems; i++)
758 array[i] = semakptr->u.sem_base[i].semval;
759 mtx_unlock(sema_mtxp);
760 error = copyout(array, arg->array, count * sizeof(*array));
761 mtx_lock(sema_mtxp);
762 break;
763
764 case GETZCNT:
765 if ((error = semvalid(semid, semakptr)) != 0)
766 goto done2;
767 if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_R)))
768 goto done2;
769 if (semnum < 0 || semnum >= semakptr->u.sem_nsems) {
770 error = EINVAL;
771 goto done2;
772 }
773 *rval = semakptr->u.sem_base[semnum].semzcnt;
774 break;
775
776 case SETVAL:
777 if ((error = semvalid(semid, semakptr)) != 0)
778 goto done2;
779 if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_W)))
780 goto done2;
781 if (semnum < 0 || semnum >= semakptr->u.sem_nsems) {
782 error = EINVAL;
783 goto done2;
784 }
785 if (arg->val < 0 || arg->val > seminfo.semvmx) {
786 error = ERANGE;
787 goto done2;
788 }
789 semakptr->u.sem_base[semnum].semval = arg->val;
790 SEMUNDO_LOCK();
791 semundo_clear(semidx, semnum);
792 SEMUNDO_UNLOCK();
793 wakeup(semakptr);
794 break;
795
796 case SETALL:
797 /*
798 * See comment on GETALL for why 'count' shouldn't change
799 * and why we require a userland buffer.
800 */
801 count = semakptr->u.sem_nsems;
802 mtx_unlock(sema_mtxp);
803 array = malloc(sizeof(*array) * count, M_TEMP, M_WAITOK);
804 error = copyin(arg->array, array, count * sizeof(*array));
805 mtx_lock(sema_mtxp);
806 if (error)
807 break;
808 if ((error = semvalid(semid, semakptr)) != 0)
809 goto done2;
810 KASSERT(count == semakptr->u.sem_nsems, ("nsems changed"));
811 if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_W)))
812 goto done2;
813 for (i = 0; i < semakptr->u.sem_nsems; i++) {
814 usval = array[i];
815 if (usval > seminfo.semvmx) {
816 error = ERANGE;
817 break;
818 }
819 semakptr->u.sem_base[i].semval = usval;
820 }
821 SEMUNDO_LOCK();
822 semundo_clear(semidx, -1);
823 SEMUNDO_UNLOCK();
824 wakeup(semakptr);
825 break;
826
827 default:
828 error = EINVAL;
829 break;
830 }
831
832done2:
833 mtx_unlock(sema_mtxp);
834 if (cmd == IPC_RMID)
835 mtx_unlock(&sem_mtx);
836 if (array != NULL)
837 free(array, M_TEMP);
838 return(error);
839}
840
841#ifndef _SYS_SYSPROTO_H_
842struct semget_args {
843 key_t key;
844 int nsems;
845 int semflg;
846};
847#endif
848int
849sys_semget(struct thread *td, struct semget_args *uap)
850{
851 int semid, error = 0;
852 int key = uap->key;
853 int nsems = uap->nsems;
854 int semflg = uap->semflg;
855 struct ucred *cred = td->td_ucred;
856
857 DPRINTF(("semget(0x%x, %d, 0%o)\n", key, nsems, semflg));
858 if (!prison_allow(td->td_ucred, PR_ALLOW_SYSVIPC))
859 return (ENOSYS);
860
861 mtx_lock(&sem_mtx);
862 if (key != IPC_PRIVATE) {
863 for (semid = 0; semid < seminfo.semmni; semid++) {
864 if ((sema[semid].u.sem_perm.mode & SEM_ALLOC) &&
865 sema[semid].u.sem_perm.key == key)
866 break;
867 }
868 if (semid < seminfo.semmni) {
869 DPRINTF(("found public key\n"));
870 if ((semflg & IPC_CREAT) && (semflg & IPC_EXCL)) {
871 DPRINTF(("not exclusive\n"));
872 error = EEXIST;
873 goto done2;
874 }
875 if ((error = ipcperm(td, &sema[semid].u.sem_perm,
876 semflg & 0700))) {
877 goto done2;
878 }
879 if (nsems > 0 && sema[semid].u.sem_nsems < nsems) {
880 DPRINTF(("too small\n"));
881 error = EINVAL;
882 goto done2;
883 }
884#ifdef MAC
885 error = mac_sysvsem_check_semget(cred, &sema[semid]);
886 if (error != 0)
887 goto done2;
888#endif
889 goto found;
890 }
891 }
892
893 DPRINTF(("need to allocate the semid_kernel\n"));
894 if (key == IPC_PRIVATE || (semflg & IPC_CREAT)) {
895 if (nsems <= 0 || nsems > seminfo.semmsl) {
896 DPRINTF(("nsems out of range (0<%d<=%d)\n", nsems,
897 seminfo.semmsl));
898 error = EINVAL;
899 goto done2;
900 }
901 if (nsems > seminfo.semmns - semtot) {
902 DPRINTF((
903 "not enough semaphores left (need %d, got %d)\n",
904 nsems, seminfo.semmns - semtot));
905 error = ENOSPC;
906 goto done2;
907 }
908 for (semid = 0; semid < seminfo.semmni; semid++) {
909 if ((sema[semid].u.sem_perm.mode & SEM_ALLOC) == 0)
910 break;
911 }
912 if (semid == seminfo.semmni) {
913 DPRINTF(("no more semid_kernel's available\n"));
914 error = ENOSPC;
915 goto done2;
916 }
917#ifdef RACCT
918 if (racct_enable) {
919 PROC_LOCK(td->td_proc);
920 error = racct_add(td->td_proc, RACCT_NSEM, nsems);
921 PROC_UNLOCK(td->td_proc);
922 if (error != 0) {
923 error = ENOSPC;
924 goto done2;
925 }
926 }
927#endif
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].cred = crhold(cred);
939 sema[semid].u.sem_perm.seq =
940 (sema[semid].u.sem_perm.seq + 1) & 0x7fff;
941 sema[semid].u.sem_nsems = nsems;
942 sema[semid].u.sem_otime = 0;
943 sema[semid].u.sem_ctime = time_second;
944 sema[semid].u.sem_base = &sem[semtot];
945 semtot += nsems;
946 bzero(sema[semid].u.sem_base,
947 sizeof(sema[semid].u.sem_base[0])*nsems);
948#ifdef MAC
949 mac_sysvsem_create(cred, &sema[semid]);
950#endif
951 mtx_unlock(&sema_mtx[semid]);
952 DPRINTF(("sembase = %p, next = %p\n",
953 sema[semid].u.sem_base, &sem[semtot]));
954 } else {
955 DPRINTF(("didn't find it and wasn't asked to create it\n"));
956 error = ENOENT;
957 goto done2;
958 }
959
960found:
961 td->td_retval[0] = IXSEQ_TO_IPCID(semid, sema[semid].u.sem_perm);
962done2:
963 mtx_unlock(&sem_mtx);
964 return (error);
965}
966
967#ifndef _SYS_SYSPROTO_H_
968struct semop_args {
969 int semid;
970 struct sembuf *sops;
971 size_t nsops;
972};
973#endif
974int
975sys_semop(struct thread *td, struct semop_args *uap)
976{
977#define SMALL_SOPS 8
978 struct sembuf small_sops[SMALL_SOPS];
979 int semid = uap->semid;
980 size_t nsops = uap->nsops;
981 struct sembuf *sops;
982 struct semid_kernel *semakptr;
| 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/racct.h>
55#include <sys/sem.h>
56#include <sys/syscall.h>
57#include <sys/syscallsubr.h>
58#include <sys/sysent.h>
59#include <sys/sysctl.h>
60#include <sys/uio.h>
61#include <sys/malloc.h>
62#include <sys/jail.h>
63
64#include <security/mac/mac_framework.h>
65
66FEATURE(sysv_sem, "System V semaphores support");
67
68static MALLOC_DEFINE(M_SEM, "sem", "SVID compatible semaphores");
69
70#ifdef SEM_DEBUG
71#define DPRINTF(a) printf a
72#else
73#define DPRINTF(a)
74#endif
75
76static int seminit(void);
77static int sysvsem_modload(struct module *, int, void *);
78static int semunload(void);
79static void semexit_myhook(void *arg, struct proc *p);
80static int sysctl_sema(SYSCTL_HANDLER_ARGS);
81static int semvalid(int semid, struct semid_kernel *semakptr);
82
83#ifndef _SYS_SYSPROTO_H_
84struct __semctl_args;
85int __semctl(struct thread *td, struct __semctl_args *uap);
86struct semget_args;
87int semget(struct thread *td, struct semget_args *uap);
88struct semop_args;
89int semop(struct thread *td, struct semop_args *uap);
90#endif
91
92static struct sem_undo *semu_alloc(struct thread *td);
93static int semundo_adjust(struct thread *td, struct sem_undo **supptr,
94 int semid, int semseq, int semnum, int adjval);
95static void semundo_clear(int semid, int semnum);
96
97static struct mtx sem_mtx; /* semaphore global lock */
98static struct mtx sem_undo_mtx;
99static int semtot = 0;
100static struct semid_kernel *sema; /* semaphore id pool */
101static struct mtx *sema_mtx; /* semaphore id pool mutexes*/
102static struct sem *sem; /* semaphore pool */
103LIST_HEAD(, sem_undo) semu_list; /* list of active undo structures */
104LIST_HEAD(, sem_undo) semu_free_list; /* list of free undo structures */
105static int *semu; /* undo structure pool */
106static eventhandler_tag semexit_tag;
107
108#define SEMUNDO_MTX sem_undo_mtx
109#define SEMUNDO_LOCK() mtx_lock(&SEMUNDO_MTX);
110#define SEMUNDO_UNLOCK() mtx_unlock(&SEMUNDO_MTX);
111#define SEMUNDO_LOCKASSERT(how) mtx_assert(&SEMUNDO_MTX, (how));
112
113struct sem {
114 u_short semval; /* semaphore value */
115 pid_t sempid; /* pid of last operation */
116 u_short semncnt; /* # awaiting semval > cval */
117 u_short semzcnt; /* # awaiting semval = 0 */
118};
119
120/*
121 * Undo structure (one per process)
122 */
123struct sem_undo {
124 LIST_ENTRY(sem_undo) un_next; /* ptr to next active undo structure */
125 struct proc *un_proc; /* owner of this structure */
126 short un_cnt; /* # of active entries */
127 struct undo {
128 short un_adjval; /* adjust on exit values */
129 short un_num; /* semaphore # */
130 int un_id; /* semid */
131 unsigned short un_seq;
132 } un_ent[1]; /* undo entries */
133};
134
135/*
136 * Configuration parameters
137 */
138#ifndef SEMMNI
139#define SEMMNI 50 /* # of semaphore identifiers */
140#endif
141#ifndef SEMMNS
142#define SEMMNS 340 /* # of semaphores in system */
143#endif
144#ifndef SEMUME
145#define SEMUME 50 /* max # of undo entries per process */
146#endif
147#ifndef SEMMNU
148#define SEMMNU 150 /* # of undo structures in system */
149#endif
150
151/* shouldn't need tuning */
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 */
181struct seminfo seminfo = {
182 SEMMNI, /* # of semaphore identifiers */
183 SEMMNS, /* # of semaphores in system */
184 SEMMNU, /* # of undo structures in system */
185 SEMMSL, /* max # of semaphores per id */
186 SEMOPM, /* max # of operations per semop call */
187 SEMUME, /* max # of undo entries per process */
188 SEMUSZ, /* size in bytes of undo structure */
189 SEMVMX, /* semaphore maximum value */
190 SEMAEM /* adjust on exit max value */
191};
192
193SYSCTL_INT(_kern_ipc, OID_AUTO, semmni, CTLFLAG_RDTUN, &seminfo.semmni, 0,
194 "Number of semaphore identifiers");
195SYSCTL_INT(_kern_ipc, OID_AUTO, semmns, CTLFLAG_RDTUN, &seminfo.semmns, 0,
196 "Maximum number of semaphores in the system");
197SYSCTL_INT(_kern_ipc, OID_AUTO, semmnu, CTLFLAG_RDTUN, &seminfo.semmnu, 0,
198 "Maximum number of undo structures in the system");
199SYSCTL_INT(_kern_ipc, OID_AUTO, semmsl, CTLFLAG_RWTUN, &seminfo.semmsl, 0,
200 "Max semaphores per id");
201SYSCTL_INT(_kern_ipc, OID_AUTO, semopm, CTLFLAG_RDTUN, &seminfo.semopm, 0,
202 "Max operations per semop call");
203SYSCTL_INT(_kern_ipc, OID_AUTO, semume, CTLFLAG_RDTUN, &seminfo.semume, 0,
204 "Max undo entries per process");
205SYSCTL_INT(_kern_ipc, OID_AUTO, semusz, CTLFLAG_RDTUN, &seminfo.semusz, 0,
206 "Size in bytes of undo structure");
207SYSCTL_INT(_kern_ipc, OID_AUTO, semvmx, CTLFLAG_RWTUN, &seminfo.semvmx, 0,
208 "Semaphore maximum value");
209SYSCTL_INT(_kern_ipc, OID_AUTO, semaem, CTLFLAG_RWTUN, &seminfo.semaem, 0,
210 "Adjust on exit max value");
211SYSCTL_PROC(_kern_ipc, OID_AUTO, sema, CTLTYPE_OPAQUE | CTLFLAG_RD,
212 NULL, 0, sysctl_sema, "", "Semaphore id pool");
213
214static struct syscall_helper_data sem_syscalls[] = {
215 SYSCALL_INIT_HELPER(__semctl),
216 SYSCALL_INIT_HELPER(semget),
217 SYSCALL_INIT_HELPER(semop),
218#if defined(COMPAT_FREEBSD4) || defined(COMPAT_FREEBSD5) || \
219 defined(COMPAT_FREEBSD6) || defined(COMPAT_FREEBSD7)
220 SYSCALL_INIT_HELPER(semsys),
221 SYSCALL_INIT_HELPER_COMPAT(freebsd7___semctl),
222#endif
223 SYSCALL_INIT_LAST
224};
225
226#ifdef COMPAT_FREEBSD32
227#include <compat/freebsd32/freebsd32.h>
228#include <compat/freebsd32/freebsd32_ipc.h>
229#include <compat/freebsd32/freebsd32_proto.h>
230#include <compat/freebsd32/freebsd32_signal.h>
231#include <compat/freebsd32/freebsd32_syscall.h>
232#include <compat/freebsd32/freebsd32_util.h>
233
234static struct syscall_helper_data sem32_syscalls[] = {
235 SYSCALL32_INIT_HELPER(freebsd32_semctl),
236 SYSCALL32_INIT_HELPER_COMPAT(semget),
237 SYSCALL32_INIT_HELPER_COMPAT(semop),
238 SYSCALL32_INIT_HELPER(freebsd32_semsys),
239#if defined(COMPAT_FREEBSD4) || defined(COMPAT_FREEBSD5) || \
240 defined(COMPAT_FREEBSD6) || defined(COMPAT_FREEBSD7)
241 SYSCALL32_INIT_HELPER(freebsd7_freebsd32_semctl),
242#endif
243 SYSCALL_INIT_LAST
244};
245#endif
246
247static int
248seminit(void)
249{
250 int i, error;
251
252 sem = malloc(sizeof(struct sem) * seminfo.semmns, M_SEM, M_WAITOK);
253 sema = malloc(sizeof(struct semid_kernel) * seminfo.semmni, M_SEM,
254 M_WAITOK);
255 sema_mtx = malloc(sizeof(struct mtx) * seminfo.semmni, M_SEM,
256 M_WAITOK | M_ZERO);
257 semu = malloc(seminfo.semmnu * seminfo.semusz, M_SEM, M_WAITOK);
258
259 for (i = 0; i < seminfo.semmni; i++) {
260 sema[i].u.sem_base = 0;
261 sema[i].u.sem_perm.mode = 0;
262 sema[i].u.sem_perm.seq = 0;
263#ifdef MAC
264 mac_sysvsem_init(&sema[i]);
265#endif
266 }
267 for (i = 0; i < seminfo.semmni; i++)
268 mtx_init(&sema_mtx[i], "semid", NULL, MTX_DEF);
269 LIST_INIT(&semu_free_list);
270 for (i = 0; i < seminfo.semmnu; i++) {
271 struct sem_undo *suptr = SEMU(i);
272 suptr->un_proc = NULL;
273 LIST_INSERT_HEAD(&semu_free_list, suptr, un_next);
274 }
275 LIST_INIT(&semu_list);
276 mtx_init(&sem_mtx, "sem", NULL, MTX_DEF);
277 mtx_init(&sem_undo_mtx, "semu", NULL, MTX_DEF);
278 semexit_tag = EVENTHANDLER_REGISTER(process_exit, semexit_myhook, NULL,
279 EVENTHANDLER_PRI_ANY);
280
281 error = syscall_helper_register(sem_syscalls, SY_THR_STATIC_KLD);
282 if (error != 0)
283 return (error);
284#ifdef COMPAT_FREEBSD32
285 error = syscall32_helper_register(sem32_syscalls, SY_THR_STATIC_KLD);
286 if (error != 0)
287 return (error);
288#endif
289 return (0);
290}
291
292static int
293semunload(void)
294{
295 int i;
296
297 /* XXXKIB */
298 if (semtot != 0)
299 return (EBUSY);
300
301#ifdef COMPAT_FREEBSD32
302 syscall32_helper_unregister(sem32_syscalls);
303#endif
304 syscall_helper_unregister(sem_syscalls);
305 EVENTHANDLER_DEREGISTER(process_exit, semexit_tag);
306#ifdef MAC
307 for (i = 0; i < seminfo.semmni; i++)
308 mac_sysvsem_destroy(&sema[i]);
309#endif
310 free(sem, M_SEM);
311 free(sema, M_SEM);
312 free(semu, M_SEM);
313 for (i = 0; i < seminfo.semmni; i++)
314 mtx_destroy(&sema_mtx[i]);
315 free(sema_mtx, M_SEM);
316 mtx_destroy(&sem_mtx);
317 mtx_destroy(&sem_undo_mtx);
318 return (0);
319}
320
321static int
322sysvsem_modload(struct module *module, int cmd, void *arg)
323{
324 int error = 0;
325
326 switch (cmd) {
327 case MOD_LOAD:
328 error = seminit();
329 if (error != 0)
330 semunload();
331 break;
332 case MOD_UNLOAD:
333 error = semunload();
334 break;
335 case MOD_SHUTDOWN:
336 break;
337 default:
338 error = EINVAL;
339 break;
340 }
341 return (error);
342}
343
344static moduledata_t sysvsem_mod = {
345 "sysvsem",
346 &sysvsem_modload,
347 NULL
348};
349
350DECLARE_MODULE(sysvsem, sysvsem_mod, SI_SUB_SYSV_SEM, SI_ORDER_FIRST);
351MODULE_VERSION(sysvsem, 1);
352
353/*
354 * Allocate a new sem_undo structure for a process
355 * (returns ptr to structure or NULL if no more room)
356 */
357
358static struct sem_undo *
359semu_alloc(struct thread *td)
360{
361 struct sem_undo *suptr;
362
363 SEMUNDO_LOCKASSERT(MA_OWNED);
364 if ((suptr = LIST_FIRST(&semu_free_list)) == NULL)
365 return (NULL);
366 LIST_REMOVE(suptr, un_next);
367 LIST_INSERT_HEAD(&semu_list, suptr, un_next);
368 suptr->un_cnt = 0;
369 suptr->un_proc = td->td_proc;
370 return (suptr);
371}
372
373static int
374semu_try_free(struct sem_undo *suptr)
375{
376
377 SEMUNDO_LOCKASSERT(MA_OWNED);
378
379 if (suptr->un_cnt != 0)
380 return (0);
381 LIST_REMOVE(suptr, un_next);
382 LIST_INSERT_HEAD(&semu_free_list, suptr, un_next);
383 return (1);
384}
385
386/*
387 * Adjust a particular entry for a particular proc
388 */
389
390static int
391semundo_adjust(struct thread *td, struct sem_undo **supptr, int semid,
392 int semseq, int semnum, int adjval)
393{
394 struct proc *p = td->td_proc;
395 struct sem_undo *suptr;
396 struct undo *sunptr;
397 int i;
398
399 SEMUNDO_LOCKASSERT(MA_OWNED);
400 /* Look for and remember the sem_undo if the caller doesn't provide
401 it */
402
403 suptr = *supptr;
404 if (suptr == NULL) {
405 LIST_FOREACH(suptr, &semu_list, un_next) {
406 if (suptr->un_proc == p) {
407 *supptr = suptr;
408 break;
409 }
410 }
411 if (suptr == NULL) {
412 if (adjval == 0)
413 return(0);
414 suptr = semu_alloc(td);
415 if (suptr == NULL)
416 return (ENOSPC);
417 *supptr = suptr;
418 }
419 }
420
421 /*
422 * Look for the requested entry and adjust it (delete if adjval becomes
423 * 0).
424 */
425 sunptr = &suptr->un_ent[0];
426 for (i = 0; i < suptr->un_cnt; i++, sunptr++) {
427 if (sunptr->un_id != semid || sunptr->un_num != semnum)
428 continue;
429 if (adjval != 0) {
430 adjval += sunptr->un_adjval;
431 if (adjval > seminfo.semaem || adjval < -seminfo.semaem)
432 return (ERANGE);
433 }
434 sunptr->un_adjval = adjval;
435 if (sunptr->un_adjval == 0) {
436 suptr->un_cnt--;
437 if (i < suptr->un_cnt)
438 suptr->un_ent[i] =
439 suptr->un_ent[suptr->un_cnt];
440 if (suptr->un_cnt == 0)
441 semu_try_free(suptr);
442 }
443 return (0);
444 }
445
446 /* Didn't find the right entry - create it */
447 if (adjval == 0)
448 return (0);
449 if (adjval > seminfo.semaem || adjval < -seminfo.semaem)
450 return (ERANGE);
451 if (suptr->un_cnt != seminfo.semume) {
452 sunptr = &suptr->un_ent[suptr->un_cnt];
453 suptr->un_cnt++;
454 sunptr->un_adjval = adjval;
455 sunptr->un_id = semid;
456 sunptr->un_num = semnum;
457 sunptr->un_seq = semseq;
458 } else
459 return (EINVAL);
460 return (0);
461}
462
463static void
464semundo_clear(int semid, int semnum)
465{
466 struct sem_undo *suptr, *suptr1;
467 struct undo *sunptr;
468 int i;
469
470 SEMUNDO_LOCKASSERT(MA_OWNED);
471 LIST_FOREACH_SAFE(suptr, &semu_list, un_next, suptr1) {
472 sunptr = &suptr->un_ent[0];
473 for (i = 0; i < suptr->un_cnt; i++, sunptr++) {
474 if (sunptr->un_id != semid)
475 continue;
476 if (semnum == -1 || sunptr->un_num == semnum) {
477 suptr->un_cnt--;
478 if (i < suptr->un_cnt) {
479 suptr->un_ent[i] =
480 suptr->un_ent[suptr->un_cnt];
481 continue;
482 }
483 semu_try_free(suptr);
484 }
485 if (semnum != -1)
486 break;
487 }
488 }
489}
490
491static int
492semvalid(int semid, struct semid_kernel *semakptr)
493{
494
495 return ((semakptr->u.sem_perm.mode & SEM_ALLOC) == 0 ||
496 semakptr->u.sem_perm.seq != IPCID_TO_SEQ(semid) ? EINVAL : 0);
497}
498
499/*
500 * Note that the user-mode half of this passes a union, not a pointer.
501 */
502#ifndef _SYS_SYSPROTO_H_
503struct __semctl_args {
504 int semid;
505 int semnum;
506 int cmd;
507 union semun *arg;
508};
509#endif
510int
511sys___semctl(struct thread *td, struct __semctl_args *uap)
512{
513 struct semid_ds dsbuf;
514 union semun arg, semun;
515 register_t rval;
516 int error;
517
518 switch (uap->cmd) {
519 case SEM_STAT:
520 case IPC_SET:
521 case IPC_STAT:
522 case GETALL:
523 case SETVAL:
524 case SETALL:
525 error = copyin(uap->arg, &arg, sizeof(arg));
526 if (error)
527 return (error);
528 break;
529 }
530
531 switch (uap->cmd) {
532 case SEM_STAT:
533 case IPC_STAT:
534 semun.buf = &dsbuf;
535 break;
536 case IPC_SET:
537 error = copyin(arg.buf, &dsbuf, sizeof(dsbuf));
538 if (error)
539 return (error);
540 semun.buf = &dsbuf;
541 break;
542 case GETALL:
543 case SETALL:
544 semun.array = arg.array;
545 break;
546 case SETVAL:
547 semun.val = arg.val;
548 break;
549 }
550
551 error = kern_semctl(td, uap->semid, uap->semnum, uap->cmd, &semun,
552 &rval);
553 if (error)
554 return (error);
555
556 switch (uap->cmd) {
557 case SEM_STAT:
558 case IPC_STAT:
559 error = copyout(&dsbuf, arg.buf, sizeof(dsbuf));
560 break;
561 }
562
563 if (error == 0)
564 td->td_retval[0] = rval;
565 return (error);
566}
567
568int
569kern_semctl(struct thread *td, int semid, int semnum, int cmd,
570 union semun *arg, register_t *rval)
571{
572 u_short *array;
573 struct ucred *cred = td->td_ucred;
574 int i, error;
575 struct semid_ds *sbuf;
576 struct semid_kernel *semakptr;
577 struct mtx *sema_mtxp;
578 u_short usval, count;
579 int semidx;
580
581 DPRINTF(("call to semctl(%d, %d, %d, 0x%p)\n",
582 semid, semnum, cmd, arg));
583 if (!prison_allow(td->td_ucred, PR_ALLOW_SYSVIPC))
584 return (ENOSYS);
585
586 array = NULL;
587
588 switch(cmd) {
589 case SEM_STAT:
590 /*
591 * For this command we assume semid is an array index
592 * rather than an IPC id.
593 */
594 if (semid < 0 || semid >= seminfo.semmni)
595 return (EINVAL);
596 semakptr = &sema[semid];
597 sema_mtxp = &sema_mtx[semid];
598 mtx_lock(sema_mtxp);
599 if ((semakptr->u.sem_perm.mode & SEM_ALLOC) == 0) {
600 error = EINVAL;
601 goto done2;
602 }
603 if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_R)))
604 goto done2;
605#ifdef MAC
606 error = mac_sysvsem_check_semctl(cred, semakptr, cmd);
607 if (error != 0)
608 goto done2;
609#endif
610 bcopy(&semakptr->u, arg->buf, sizeof(struct semid_ds));
611 *rval = IXSEQ_TO_IPCID(semid, semakptr->u.sem_perm);
612 mtx_unlock(sema_mtxp);
613 return (0);
614 }
615
616 semidx = IPCID_TO_IX(semid);
617 if (semidx < 0 || semidx >= seminfo.semmni)
618 return (EINVAL);
619
620 semakptr = &sema[semidx];
621 sema_mtxp = &sema_mtx[semidx];
622 if (cmd == IPC_RMID)
623 mtx_lock(&sem_mtx);
624 mtx_lock(sema_mtxp);
625#ifdef MAC
626 error = mac_sysvsem_check_semctl(cred, semakptr, cmd);
627 if (error != 0)
628 goto done2;
629#endif
630
631 error = 0;
632 *rval = 0;
633
634 switch (cmd) {
635 case IPC_RMID:
636 if ((error = semvalid(semid, semakptr)) != 0)
637 goto done2;
638 if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_M)))
639 goto done2;
640 semakptr->u.sem_perm.cuid = cred->cr_uid;
641 semakptr->u.sem_perm.uid = cred->cr_uid;
642 semakptr->u.sem_perm.mode = 0;
643 racct_sub_cred(semakptr->cred, RACCT_NSEM, semakptr->u.sem_nsems);
644 crfree(semakptr->cred);
645 semakptr->cred = NULL;
646 SEMUNDO_LOCK();
647 semundo_clear(semidx, -1);
648 SEMUNDO_UNLOCK();
649#ifdef MAC
650 mac_sysvsem_cleanup(semakptr);
651#endif
652 wakeup(semakptr);
653 for (i = 0; i < seminfo.semmni; i++) {
654 if ((sema[i].u.sem_perm.mode & SEM_ALLOC) &&
655 sema[i].u.sem_base > semakptr->u.sem_base)
656 mtx_lock_flags(&sema_mtx[i], LOP_DUPOK);
657 }
658 for (i = semakptr->u.sem_base - sem; i < semtot; i++)
659 sem[i] = sem[i + semakptr->u.sem_nsems];
660 for (i = 0; i < seminfo.semmni; i++) {
661 if ((sema[i].u.sem_perm.mode & SEM_ALLOC) &&
662 sema[i].u.sem_base > semakptr->u.sem_base) {
663 sema[i].u.sem_base -= semakptr->u.sem_nsems;
664 mtx_unlock(&sema_mtx[i]);
665 }
666 }
667 semtot -= semakptr->u.sem_nsems;
668 break;
669
670 case IPC_SET:
671 if ((error = semvalid(semid, semakptr)) != 0)
672 goto done2;
673 if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_M)))
674 goto done2;
675 sbuf = arg->buf;
676 semakptr->u.sem_perm.uid = sbuf->sem_perm.uid;
677 semakptr->u.sem_perm.gid = sbuf->sem_perm.gid;
678 semakptr->u.sem_perm.mode = (semakptr->u.sem_perm.mode &
679 ~0777) | (sbuf->sem_perm.mode & 0777);
680 semakptr->u.sem_ctime = time_second;
681 break;
682
683 case IPC_STAT:
684 if ((error = semvalid(semid, semakptr)) != 0)
685 goto done2;
686 if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_R)))
687 goto done2;
688 bcopy(&semakptr->u, arg->buf, sizeof(struct semid_ds));
689 break;
690
691 case GETNCNT:
692 if ((error = semvalid(semid, semakptr)) != 0)
693 goto done2;
694 if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_R)))
695 goto done2;
696 if (semnum < 0 || semnum >= semakptr->u.sem_nsems) {
697 error = EINVAL;
698 goto done2;
699 }
700 *rval = semakptr->u.sem_base[semnum].semncnt;
701 break;
702
703 case GETPID:
704 if ((error = semvalid(semid, semakptr)) != 0)
705 goto done2;
706 if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_R)))
707 goto done2;
708 if (semnum < 0 || semnum >= semakptr->u.sem_nsems) {
709 error = EINVAL;
710 goto done2;
711 }
712 *rval = semakptr->u.sem_base[semnum].sempid;
713 break;
714
715 case GETVAL:
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].semval;
725 break;
726
727 case GETALL:
728 /*
729 * Unfortunately, callers of this function don't know
730 * in advance how many semaphores are in this set.
731 * While we could just allocate the maximum size array
732 * and pass the actual size back to the caller, that
733 * won't work for SETALL since we can't copyin() more
734 * data than the user specified as we may return a
735 * spurious EFAULT.
736 *
737 * Note that the number of semaphores in a set is
738 * fixed for the life of that set. The only way that
739 * the 'count' could change while are blocked in
740 * malloc() is if this semaphore set were destroyed
741 * and a new one created with the same index.
742 * However, semvalid() will catch that due to the
743 * sequence number unless exactly 0x8000 (or a
744 * multiple thereof) semaphore sets for the same index
745 * are created and destroyed while we are in malloc!
746 *
747 */
748 count = semakptr->u.sem_nsems;
749 mtx_unlock(sema_mtxp);
750 array = malloc(sizeof(*array) * count, M_TEMP, M_WAITOK);
751 mtx_lock(sema_mtxp);
752 if ((error = semvalid(semid, semakptr)) != 0)
753 goto done2;
754 KASSERT(count == semakptr->u.sem_nsems, ("nsems changed"));
755 if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_R)))
756 goto done2;
757 for (i = 0; i < semakptr->u.sem_nsems; i++)
758 array[i] = semakptr->u.sem_base[i].semval;
759 mtx_unlock(sema_mtxp);
760 error = copyout(array, arg->array, count * sizeof(*array));
761 mtx_lock(sema_mtxp);
762 break;
763
764 case GETZCNT:
765 if ((error = semvalid(semid, semakptr)) != 0)
766 goto done2;
767 if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_R)))
768 goto done2;
769 if (semnum < 0 || semnum >= semakptr->u.sem_nsems) {
770 error = EINVAL;
771 goto done2;
772 }
773 *rval = semakptr->u.sem_base[semnum].semzcnt;
774 break;
775
776 case SETVAL:
777 if ((error = semvalid(semid, semakptr)) != 0)
778 goto done2;
779 if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_W)))
780 goto done2;
781 if (semnum < 0 || semnum >= semakptr->u.sem_nsems) {
782 error = EINVAL;
783 goto done2;
784 }
785 if (arg->val < 0 || arg->val > seminfo.semvmx) {
786 error = ERANGE;
787 goto done2;
788 }
789 semakptr->u.sem_base[semnum].semval = arg->val;
790 SEMUNDO_LOCK();
791 semundo_clear(semidx, semnum);
792 SEMUNDO_UNLOCK();
793 wakeup(semakptr);
794 break;
795
796 case SETALL:
797 /*
798 * See comment on GETALL for why 'count' shouldn't change
799 * and why we require a userland buffer.
800 */
801 count = semakptr->u.sem_nsems;
802 mtx_unlock(sema_mtxp);
803 array = malloc(sizeof(*array) * count, M_TEMP, M_WAITOK);
804 error = copyin(arg->array, array, count * sizeof(*array));
805 mtx_lock(sema_mtxp);
806 if (error)
807 break;
808 if ((error = semvalid(semid, semakptr)) != 0)
809 goto done2;
810 KASSERT(count == semakptr->u.sem_nsems, ("nsems changed"));
811 if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_W)))
812 goto done2;
813 for (i = 0; i < semakptr->u.sem_nsems; i++) {
814 usval = array[i];
815 if (usval > seminfo.semvmx) {
816 error = ERANGE;
817 break;
818 }
819 semakptr->u.sem_base[i].semval = usval;
820 }
821 SEMUNDO_LOCK();
822 semundo_clear(semidx, -1);
823 SEMUNDO_UNLOCK();
824 wakeup(semakptr);
825 break;
826
827 default:
828 error = EINVAL;
829 break;
830 }
831
832done2:
833 mtx_unlock(sema_mtxp);
834 if (cmd == IPC_RMID)
835 mtx_unlock(&sem_mtx);
836 if (array != NULL)
837 free(array, M_TEMP);
838 return(error);
839}
840
841#ifndef _SYS_SYSPROTO_H_
842struct semget_args {
843 key_t key;
844 int nsems;
845 int semflg;
846};
847#endif
848int
849sys_semget(struct thread *td, struct semget_args *uap)
850{
851 int semid, error = 0;
852 int key = uap->key;
853 int nsems = uap->nsems;
854 int semflg = uap->semflg;
855 struct ucred *cred = td->td_ucred;
856
857 DPRINTF(("semget(0x%x, %d, 0%o)\n", key, nsems, semflg));
858 if (!prison_allow(td->td_ucred, PR_ALLOW_SYSVIPC))
859 return (ENOSYS);
860
861 mtx_lock(&sem_mtx);
862 if (key != IPC_PRIVATE) {
863 for (semid = 0; semid < seminfo.semmni; semid++) {
864 if ((sema[semid].u.sem_perm.mode & SEM_ALLOC) &&
865 sema[semid].u.sem_perm.key == key)
866 break;
867 }
868 if (semid < seminfo.semmni) {
869 DPRINTF(("found public key\n"));
870 if ((semflg & IPC_CREAT) && (semflg & IPC_EXCL)) {
871 DPRINTF(("not exclusive\n"));
872 error = EEXIST;
873 goto done2;
874 }
875 if ((error = ipcperm(td, &sema[semid].u.sem_perm,
876 semflg & 0700))) {
877 goto done2;
878 }
879 if (nsems > 0 && sema[semid].u.sem_nsems < nsems) {
880 DPRINTF(("too small\n"));
881 error = EINVAL;
882 goto done2;
883 }
884#ifdef MAC
885 error = mac_sysvsem_check_semget(cred, &sema[semid]);
886 if (error != 0)
887 goto done2;
888#endif
889 goto found;
890 }
891 }
892
893 DPRINTF(("need to allocate the semid_kernel\n"));
894 if (key == IPC_PRIVATE || (semflg & IPC_CREAT)) {
895 if (nsems <= 0 || nsems > seminfo.semmsl) {
896 DPRINTF(("nsems out of range (0<%d<=%d)\n", nsems,
897 seminfo.semmsl));
898 error = EINVAL;
899 goto done2;
900 }
901 if (nsems > seminfo.semmns - semtot) {
902 DPRINTF((
903 "not enough semaphores left (need %d, got %d)\n",
904 nsems, seminfo.semmns - semtot));
905 error = ENOSPC;
906 goto done2;
907 }
908 for (semid = 0; semid < seminfo.semmni; semid++) {
909 if ((sema[semid].u.sem_perm.mode & SEM_ALLOC) == 0)
910 break;
911 }
912 if (semid == seminfo.semmni) {
913 DPRINTF(("no more semid_kernel's available\n"));
914 error = ENOSPC;
915 goto done2;
916 }
917#ifdef RACCT
918 if (racct_enable) {
919 PROC_LOCK(td->td_proc);
920 error = racct_add(td->td_proc, RACCT_NSEM, nsems);
921 PROC_UNLOCK(td->td_proc);
922 if (error != 0) {
923 error = ENOSPC;
924 goto done2;
925 }
926 }
927#endif
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].cred = crhold(cred);
939 sema[semid].u.sem_perm.seq =
940 (sema[semid].u.sem_perm.seq + 1) & 0x7fff;
941 sema[semid].u.sem_nsems = nsems;
942 sema[semid].u.sem_otime = 0;
943 sema[semid].u.sem_ctime = time_second;
944 sema[semid].u.sem_base = &sem[semtot];
945 semtot += nsems;
946 bzero(sema[semid].u.sem_base,
947 sizeof(sema[semid].u.sem_base[0])*nsems);
948#ifdef MAC
949 mac_sysvsem_create(cred, &sema[semid]);
950#endif
951 mtx_unlock(&sema_mtx[semid]);
952 DPRINTF(("sembase = %p, next = %p\n",
953 sema[semid].u.sem_base, &sem[semtot]));
954 } else {
955 DPRINTF(("didn't find it and wasn't asked to create it\n"));
956 error = ENOENT;
957 goto done2;
958 }
959
960found:
961 td->td_retval[0] = IXSEQ_TO_IPCID(semid, sema[semid].u.sem_perm);
962done2:
963 mtx_unlock(&sem_mtx);
964 return (error);
965}
966
967#ifndef _SYS_SYSPROTO_H_
968struct semop_args {
969 int semid;
970 struct sembuf *sops;
971 size_t nsops;
972};
973#endif
974int
975sys_semop(struct thread *td, struct semop_args *uap)
976{
977#define SMALL_SOPS 8
978 struct sembuf small_sops[SMALL_SOPS];
979 int semid = uap->semid;
980 size_t nsops = uap->nsops;
981 struct sembuf *sops;
982 struct semid_kernel *semakptr;
|
985 struct sem_undo *suptr;
986 struct mtx *sema_mtxp;
987 size_t i, j, k;
988 int error;
989 int do_wakeup, do_undos;
990 unsigned short seq;
991
992#ifdef SEM_DEBUG
993 sops = NULL;
994#endif
995 DPRINTF(("call to semop(%d, %p, %u)\n", semid, sops, nsops));
996
997 if (!prison_allow(td->td_ucred, PR_ALLOW_SYSVIPC))
998 return (ENOSYS);
999
1000 semid = IPCID_TO_IX(semid); /* Convert back to zero origin */
1001
1002 if (semid < 0 || semid >= seminfo.semmni)
1003 return (EINVAL);
1004
1005 /* Allocate memory for sem_ops */
1006 if (nsops <= SMALL_SOPS)
1007 sops = small_sops;
1008 else if (nsops > seminfo.semopm) {
1009 DPRINTF(("too many sops (max=%d, nsops=%d)\n", seminfo.semopm,
1010 nsops));
1011 return (E2BIG);
1012 } else {
1013#ifdef RACCT
1014 if (racct_enable) {
1015 PROC_LOCK(td->td_proc);
1016 if (nsops >
1017 racct_get_available(td->td_proc, RACCT_NSEMOP)) {
1018 PROC_UNLOCK(td->td_proc);
1019 return (E2BIG);
1020 }
1021 PROC_UNLOCK(td->td_proc);
1022 }
1023#endif
1024
1025 sops = malloc(nsops * sizeof(*sops), M_TEMP, M_WAITOK);
1026 }
1027 if ((error = copyin(uap->sops, sops, nsops * sizeof(sops[0]))) != 0) {
1028 DPRINTF(("error = %d from copyin(%p, %p, %d)\n", error,
1029 uap->sops, sops, nsops * sizeof(sops[0])));
1030 if (sops != small_sops)
1031 free(sops, M_SEM);
1032 return (error);
1033 }
1034
1035 semakptr = &sema[semid];
1036 sema_mtxp = &sema_mtx[semid];
1037 mtx_lock(sema_mtxp);
1038 if ((semakptr->u.sem_perm.mode & SEM_ALLOC) == 0) {
1039 error = EINVAL;
1040 goto done2;
1041 }
1042 seq = semakptr->u.sem_perm.seq;
1043 if (seq != IPCID_TO_SEQ(uap->semid)) {
1044 error = EINVAL;
1045 goto done2;
1046 }
1047 /*
1048 * Initial pass thru sops to see what permissions are needed.
1049 * Also perform any checks that don't need repeating on each
1050 * attempt to satisfy the request vector.
1051 */
1052 j = 0; /* permission needed */
1053 do_undos = 0;
1054 for (i = 0; i < nsops; i++) {
1055 sopptr = &sops[i];
1056 if (sopptr->sem_num >= semakptr->u.sem_nsems) {
1057 error = EFBIG;
1058 goto done2;
1059 }
1060 if (sopptr->sem_flg & SEM_UNDO && sopptr->sem_op != 0)
1061 do_undos = 1;
1062 j |= (sopptr->sem_op == 0) ? SEM_R : SEM_A;
1063 }
1064
1065 if ((error = ipcperm(td, &semakptr->u.sem_perm, j))) {
1066 DPRINTF(("error = %d from ipaccess\n", error));
1067 goto done2;
1068 }
1069#ifdef MAC
1070 error = mac_sysvsem_check_semop(td->td_ucred, semakptr, j);
1071 if (error != 0)
1072 goto done2;
1073#endif
1074
1075 /*
1076 * Loop trying to satisfy the vector of requests.
1077 * If we reach a point where we must wait, any requests already
1078 * performed are rolled back and we go to sleep until some other
1079 * process wakes us up. At this point, we start all over again.
1080 *
1081 * This ensures that from the perspective of other tasks, a set
1082 * of requests is atomic (never partially satisfied).
1083 */
1084 for (;;) {
1085 do_wakeup = 0;
1086 error = 0; /* error return if necessary */
1087
1088 for (i = 0; i < nsops; i++) {
1089 sopptr = &sops[i];
1090 semptr = &semakptr->u.sem_base[sopptr->sem_num];
1091
1092 DPRINTF((
1093 "semop: semakptr=%p, sem_base=%p, "
1094 "semptr=%p, sem[%d]=%d : op=%d, flag=%s\n",
1095 semakptr, semakptr->u.sem_base, semptr,
1096 sopptr->sem_num, semptr->semval, sopptr->sem_op,
1097 (sopptr->sem_flg & IPC_NOWAIT) ?
1098 "nowait" : "wait"));
1099
1100 if (sopptr->sem_op < 0) {
1101 if (semptr->semval + sopptr->sem_op < 0) {
1102 DPRINTF(("semop: can't do it now\n"));
1103 break;
1104 } else {
1105 semptr->semval += sopptr->sem_op;
1106 if (semptr->semval == 0 &&
1107 semptr->semzcnt > 0)
1108 do_wakeup = 1;
1109 }
1110 } else if (sopptr->sem_op == 0) {
1111 if (semptr->semval != 0) {
1112 DPRINTF(("semop: not zero now\n"));
1113 break;
1114 }
1115 } else if (semptr->semval + sopptr->sem_op >
1116 seminfo.semvmx) {
1117 error = ERANGE;
1118 break;
1119 } else {
1120 if (semptr->semncnt > 0)
1121 do_wakeup = 1;
1122 semptr->semval += sopptr->sem_op;
1123 }
1124 }
1125
1126 /*
1127 * Did we get through the entire vector?
1128 */
1129 if (i >= nsops)
1130 goto done;
1131
1132 /*
1133 * No ... rollback anything that we've already done
1134 */
1135 DPRINTF(("semop: rollback 0 through %d\n", i-1));
1136 for (j = 0; j < i; j++)
1137 semakptr->u.sem_base[sops[j].sem_num].semval -=
1138 sops[j].sem_op;
1139
1140 /* If we detected an error, return it */
1141 if (error != 0)
1142 goto done2;
1143
1144 /*
1145 * If the request that we couldn't satisfy has the
1146 * NOWAIT flag set then return with EAGAIN.
1147 */
1148 if (sopptr->sem_flg & IPC_NOWAIT) {
1149 error = EAGAIN;
1150 goto done2;
1151 }
1152
1153 if (sopptr->sem_op == 0)
1154 semptr->semzcnt++;
1155 else
1156 semptr->semncnt++;
1157
1158 DPRINTF(("semop: good night!\n"));
1159 error = msleep(semakptr, sema_mtxp, (PZERO - 4) | PCATCH,
1160 "semwait", 0);
1161 DPRINTF(("semop: good morning (error=%d)!\n", error));
1162 /* return code is checked below, after sem[nz]cnt-- */
1163
1164 /*
1165 * Make sure that the semaphore still exists
1166 */
1167 seq = semakptr->u.sem_perm.seq;
1168 if ((semakptr->u.sem_perm.mode & SEM_ALLOC) == 0 ||
1169 seq != IPCID_TO_SEQ(uap->semid)) {
1170 error = EIDRM;
1171 goto done2;
1172 }
1173
1174 /*
1175 * Renew the semaphore's pointer after wakeup since
1176 * during msleep sem_base may have been modified and semptr
1177 * is not valid any more
1178 */
1179 semptr = &semakptr->u.sem_base[sopptr->sem_num];
1180
1181 /*
1182 * The semaphore is still alive. Readjust the count of
1183 * waiting processes.
1184 */
1185 if (sopptr->sem_op == 0)
1186 semptr->semzcnt--;
1187 else
1188 semptr->semncnt--;
1189
1190 /*
1191 * Is it really morning, or was our sleep interrupted?
1192 * (Delayed check of msleep() return code because we
1193 * need to decrement sem[nz]cnt either way.)
1194 */
1195 if (error != 0) {
1196 error = EINTR;
1197 goto done2;
1198 }
1199 DPRINTF(("semop: good morning!\n"));
1200 }
1201
1202done:
1203 /*
1204 * Process any SEM_UNDO requests.
1205 */
1206 if (do_undos) {
1207 SEMUNDO_LOCK();
1208 suptr = NULL;
1209 for (i = 0; i < nsops; i++) {
1210 /*
1211 * We only need to deal with SEM_UNDO's for non-zero
1212 * op's.
1213 */
1214 int adjval;
1215
1216 if ((sops[i].sem_flg & SEM_UNDO) == 0)
1217 continue;
1218 adjval = sops[i].sem_op;
1219 if (adjval == 0)
1220 continue;
1221 error = semundo_adjust(td, &suptr, semid, seq,
1222 sops[i].sem_num, -adjval);
1223 if (error == 0)
1224 continue;
1225
1226 /*
1227 * Oh-Oh! We ran out of either sem_undo's or undo's.
1228 * Rollback the adjustments to this point and then
1229 * rollback the semaphore ups and down so we can return
1230 * with an error with all structures restored. We
1231 * rollback the undo's in the exact reverse order that
1232 * we applied them. This guarantees that we won't run
1233 * out of space as we roll things back out.
1234 */
1235 for (j = 0; j < i; j++) {
1236 k = i - j - 1;
1237 if ((sops[k].sem_flg & SEM_UNDO) == 0)
1238 continue;
1239 adjval = sops[k].sem_op;
1240 if (adjval == 0)
1241 continue;
1242 if (semundo_adjust(td, &suptr, semid, seq,
1243 sops[k].sem_num, adjval) != 0)
1244 panic("semop - can't undo undos");
1245 }
1246
1247 for (j = 0; j < nsops; j++)
1248 semakptr->u.sem_base[sops[j].sem_num].semval -=
1249 sops[j].sem_op;
1250
1251 DPRINTF(("error = %d from semundo_adjust\n", error));
1252 SEMUNDO_UNLOCK();
1253 goto done2;
1254 } /* loop through the sops */
1255 SEMUNDO_UNLOCK();
1256 } /* if (do_undos) */
1257
1258 /* We're definitely done - set the sempid's and time */
1259 for (i = 0; i < nsops; i++) {
1260 sopptr = &sops[i];
1261 semptr = &semakptr->u.sem_base[sopptr->sem_num];
1262 semptr->sempid = td->td_proc->p_pid;
1263 }
1264 semakptr->u.sem_otime = time_second;
1265
1266 /*
1267 * Do a wakeup if any semaphore was up'd whilst something was
1268 * sleeping on it.
1269 */
1270 if (do_wakeup) {
1271 DPRINTF(("semop: doing wakeup\n"));
1272 wakeup(semakptr);
1273 DPRINTF(("semop: back from wakeup\n"));
1274 }
1275 DPRINTF(("semop: done\n"));
1276 td->td_retval[0] = 0;
1277done2:
1278 mtx_unlock(sema_mtxp);
1279 if (sops != small_sops)
1280 free(sops, M_SEM);
1281 return (error);
1282}
1283
1284/*
1285 * Go through the undo structures for this process and apply the adjustments to
1286 * semaphores.
1287 */
1288static void
1289semexit_myhook(void *arg, struct proc *p)
1290{
1291 struct sem_undo *suptr;
1292 struct semid_kernel *semakptr;
1293 struct mtx *sema_mtxp;
1294 int semid, semnum, adjval, ix;
1295 unsigned short seq;
1296
1297 /*
1298 * Go through the chain of undo vectors looking for one
1299 * associated with this process.
1300 */
1301 SEMUNDO_LOCK();
1302 LIST_FOREACH(suptr, &semu_list, un_next) {
1303 if (suptr->un_proc == p)
1304 break;
1305 }
1306 if (suptr == NULL) {
1307 SEMUNDO_UNLOCK();
1308 return;
1309 }
1310 LIST_REMOVE(suptr, un_next);
1311
1312 DPRINTF(("proc @%p has undo structure with %d entries\n", p,
1313 suptr->un_cnt));
1314
1315 /*
1316 * If there are any active undo elements then process them.
1317 */
1318 if (suptr->un_cnt > 0) {
1319 SEMUNDO_UNLOCK();
1320 for (ix = 0; ix < suptr->un_cnt; ix++) {
1321 semid = suptr->un_ent[ix].un_id;
1322 semnum = suptr->un_ent[ix].un_num;
1323 adjval = suptr->un_ent[ix].un_adjval;
1324 seq = suptr->un_ent[ix].un_seq;
1325 semakptr = &sema[semid];
1326 sema_mtxp = &sema_mtx[semid];
1327
1328 mtx_lock(sema_mtxp);
1329 if ((semakptr->u.sem_perm.mode & SEM_ALLOC) == 0 ||
1330 (semakptr->u.sem_perm.seq != seq)) {
1331 mtx_unlock(sema_mtxp);
1332 continue;
1333 }
1334 if (semnum >= semakptr->u.sem_nsems)
1335 panic("semexit - semnum out of range");
1336
1337 DPRINTF((
1338 "semexit: %p id=%d num=%d(adj=%d) ; sem=%d\n",
1339 suptr->un_proc, suptr->un_ent[ix].un_id,
1340 suptr->un_ent[ix].un_num,
1341 suptr->un_ent[ix].un_adjval,
1342 semakptr->u.sem_base[semnum].semval));
1343
1344 if (adjval < 0 && semakptr->u.sem_base[semnum].semval <
1345 -adjval)
1346 semakptr->u.sem_base[semnum].semval = 0;
1347 else
1348 semakptr->u.sem_base[semnum].semval += adjval;
1349
1350 wakeup(semakptr);
1351 DPRINTF(("semexit: back from wakeup\n"));
1352 mtx_unlock(sema_mtxp);
1353 }
1354 SEMUNDO_LOCK();
1355 }
1356
1357 /*
1358 * Deallocate the undo vector.
1359 */
1360 DPRINTF(("removing vector\n"));
1361 suptr->un_proc = NULL;
1362 suptr->un_cnt = 0;
1363 LIST_INSERT_HEAD(&semu_free_list, suptr, un_next);
1364 SEMUNDO_UNLOCK();
1365}
1366
1367static int
1368sysctl_sema(SYSCTL_HANDLER_ARGS)
1369{
1370
1371 return (SYSCTL_OUT(req, sema,
1372 sizeof(struct semid_kernel) * seminfo.semmni));
1373}
1374
1375#if defined(COMPAT_FREEBSD4) || defined(COMPAT_FREEBSD5) || \
1376 defined(COMPAT_FREEBSD6) || defined(COMPAT_FREEBSD7)
1377
1378/* XXX casting to (sy_call_t *) is bogus, as usual. */
1379static sy_call_t *semcalls[] = {
1380 (sy_call_t *)freebsd7___semctl, (sy_call_t *)sys_semget,
1381 (sy_call_t *)sys_semop
1382};
1383
1384/*
1385 * Entry point for all SEM calls.
1386 */
1387int
1388sys_semsys(td, uap)
1389 struct thread *td;
1390 /* XXX actually varargs. */
1391 struct semsys_args /* {
1392 int which;
1393 int a2;
1394 int a3;
1395 int a4;
1396 int a5;
1397 } */ *uap;
1398{
1399 int error;
1400
1401 if (!prison_allow(td->td_ucred, PR_ALLOW_SYSVIPC))
1402 return (ENOSYS);
1403 if (uap->which < 0 ||
1404 uap->which >= sizeof(semcalls)/sizeof(semcalls[0]))
1405 return (EINVAL);
1406 error = (*semcalls[uap->which])(td, &uap->a2);
1407 return (error);
1408}
1409
1410#ifndef CP
1411#define CP(src, dst, fld) do { (dst).fld = (src).fld; } while (0)
1412#endif
1413
1414#ifndef _SYS_SYSPROTO_H_
1415struct freebsd7___semctl_args {
1416 int semid;
1417 int semnum;
1418 int cmd;
1419 union semun_old *arg;
1420};
1421#endif
1422int
1423freebsd7___semctl(struct thread *td, struct freebsd7___semctl_args *uap)
1424{
1425 struct semid_ds_old dsold;
1426 struct semid_ds dsbuf;
1427 union semun_old arg;
1428 union semun semun;
1429 register_t rval;
1430 int error;
1431
1432 switch (uap->cmd) {
1433 case SEM_STAT:
1434 case IPC_SET:
1435 case IPC_STAT:
1436 case GETALL:
1437 case SETVAL:
1438 case SETALL:
1439 error = copyin(uap->arg, &arg, sizeof(arg));
1440 if (error)
1441 return (error);
1442 break;
1443 }
1444
1445 switch (uap->cmd) {
1446 case SEM_STAT:
1447 case IPC_STAT:
1448 semun.buf = &dsbuf;
1449 break;
1450 case IPC_SET:
1451 error = copyin(arg.buf, &dsold, sizeof(dsold));
1452 if (error)
1453 return (error);
1454 ipcperm_old2new(&dsold.sem_perm, &dsbuf.sem_perm);
1455 CP(dsold, dsbuf, sem_base);
1456 CP(dsold, dsbuf, sem_nsems);
1457 CP(dsold, dsbuf, sem_otime);
1458 CP(dsold, dsbuf, sem_ctime);
1459 semun.buf = &dsbuf;
1460 break;
1461 case GETALL:
1462 case SETALL:
1463 semun.array = arg.array;
1464 break;
1465 case SETVAL:
1466 semun.val = arg.val;
1467 break;
1468 }
1469
1470 error = kern_semctl(td, uap->semid, uap->semnum, uap->cmd, &semun,
1471 &rval);
1472 if (error)
1473 return (error);
1474
1475 switch (uap->cmd) {
1476 case SEM_STAT:
1477 case IPC_STAT:
1478 bzero(&dsold, sizeof(dsold));
1479 ipcperm_new2old(&dsbuf.sem_perm, &dsold.sem_perm);
1480 CP(dsbuf, dsold, sem_base);
1481 CP(dsbuf, dsold, sem_nsems);
1482 CP(dsbuf, dsold, sem_otime);
1483 CP(dsbuf, dsold, sem_ctime);
1484 error = copyout(&dsold, arg.buf, sizeof(dsold));
1485 break;
1486 }
1487
1488 if (error == 0)
1489 td->td_retval[0] = rval;
1490 return (error);
1491}
1492
1493#endif /* COMPAT_FREEBSD{4,5,6,7} */
1494
1495#ifdef COMPAT_FREEBSD32
1496
1497int
1498freebsd32_semsys(struct thread *td, struct freebsd32_semsys_args *uap)
1499{
1500
1501#if defined(COMPAT_FREEBSD4) || defined(COMPAT_FREEBSD5) || \
1502 defined(COMPAT_FREEBSD6) || defined(COMPAT_FREEBSD7)
1503 switch (uap->which) {
1504 case 0:
1505 return (freebsd7_freebsd32_semctl(td,
1506 (struct freebsd7_freebsd32_semctl_args *)&uap->a2));
1507 default:
1508 return (sys_semsys(td, (struct semsys_args *)uap));
1509 }
1510#else
1511 return (nosys(td, NULL));
1512#endif
1513}
1514
1515#if defined(COMPAT_FREEBSD4) || defined(COMPAT_FREEBSD5) || \
1516 defined(COMPAT_FREEBSD6) || defined(COMPAT_FREEBSD7)
1517int
1518freebsd7_freebsd32_semctl(struct thread *td,
1519 struct freebsd7_freebsd32_semctl_args *uap)
1520{
1521 struct semid_ds32_old dsbuf32;
1522 struct semid_ds dsbuf;
1523 union semun semun;
1524 union semun32 arg;
1525 register_t rval;
1526 int error;
1527
1528 switch (uap->cmd) {
1529 case SEM_STAT:
1530 case IPC_SET:
1531 case IPC_STAT:
1532 case GETALL:
1533 case SETVAL:
1534 case SETALL:
1535 error = copyin(uap->arg, &arg, sizeof(arg));
1536 if (error)
1537 return (error);
1538 break;
1539 }
1540
1541 switch (uap->cmd) {
1542 case SEM_STAT:
1543 case IPC_STAT:
1544 semun.buf = &dsbuf;
1545 break;
1546 case IPC_SET:
1547 error = copyin(PTRIN(arg.buf), &dsbuf32, sizeof(dsbuf32));
1548 if (error)
1549 return (error);
1550 freebsd32_ipcperm_old_in(&dsbuf32.sem_perm, &dsbuf.sem_perm);
1551 PTRIN_CP(dsbuf32, dsbuf, sem_base);
1552 CP(dsbuf32, dsbuf, sem_nsems);
1553 CP(dsbuf32, dsbuf, sem_otime);
1554 CP(dsbuf32, dsbuf, sem_ctime);
1555 semun.buf = &dsbuf;
1556 break;
1557 case GETALL:
1558 case SETALL:
1559 semun.array = PTRIN(arg.array);
1560 break;
1561 case SETVAL:
1562 semun.val = arg.val;
1563 break;
1564 }
1565
1566 error = kern_semctl(td, uap->semid, uap->semnum, uap->cmd, &semun,
1567 &rval);
1568 if (error)
1569 return (error);
1570
1571 switch (uap->cmd) {
1572 case SEM_STAT:
1573 case IPC_STAT:
1574 bzero(&dsbuf32, sizeof(dsbuf32));
1575 freebsd32_ipcperm_old_out(&dsbuf.sem_perm, &dsbuf32.sem_perm);
1576 PTROUT_CP(dsbuf, dsbuf32, sem_base);
1577 CP(dsbuf, dsbuf32, sem_nsems);
1578 CP(dsbuf, dsbuf32, sem_otime);
1579 CP(dsbuf, dsbuf32, sem_ctime);
1580 error = copyout(&dsbuf32, PTRIN(arg.buf), sizeof(dsbuf32));
1581 break;
1582 }
1583
1584 if (error == 0)
1585 td->td_retval[0] = rval;
1586 return (error);
1587}
1588#endif
1589
1590int
1591freebsd32_semctl(struct thread *td, struct freebsd32_semctl_args *uap)
1592{
1593 struct semid_ds32 dsbuf32;
1594 struct semid_ds dsbuf;
1595 union semun semun;
1596 union semun32 arg;
1597 register_t rval;
1598 int error;
1599
1600 switch (uap->cmd) {
1601 case SEM_STAT:
1602 case IPC_SET:
1603 case IPC_STAT:
1604 case GETALL:
1605 case SETVAL:
1606 case SETALL:
1607 error = copyin(uap->arg, &arg, sizeof(arg));
1608 if (error)
1609 return (error);
1610 break;
1611 }
1612
1613 switch (uap->cmd) {
1614 case SEM_STAT:
1615 case IPC_STAT:
1616 semun.buf = &dsbuf;
1617 break;
1618 case IPC_SET:
1619 error = copyin(PTRIN(arg.buf), &dsbuf32, sizeof(dsbuf32));
1620 if (error)
1621 return (error);
1622 freebsd32_ipcperm_in(&dsbuf32.sem_perm, &dsbuf.sem_perm);
1623 PTRIN_CP(dsbuf32, dsbuf, sem_base);
1624 CP(dsbuf32, dsbuf, sem_nsems);
1625 CP(dsbuf32, dsbuf, sem_otime);
1626 CP(dsbuf32, dsbuf, sem_ctime);
1627 semun.buf = &dsbuf;
1628 break;
1629 case GETALL:
1630 case SETALL:
1631 semun.array = PTRIN(arg.array);
1632 break;
1633 case SETVAL:
1634 semun.val = arg.val;
1635 break;
1636 }
1637
1638 error = kern_semctl(td, uap->semid, uap->semnum, uap->cmd, &semun,
1639 &rval);
1640 if (error)
1641 return (error);
1642
1643 switch (uap->cmd) {
1644 case SEM_STAT:
1645 case IPC_STAT:
1646 bzero(&dsbuf32, sizeof(dsbuf32));
1647 freebsd32_ipcperm_out(&dsbuf.sem_perm, &dsbuf32.sem_perm);
1648 PTROUT_CP(dsbuf, dsbuf32, sem_base);
1649 CP(dsbuf, dsbuf32, sem_nsems);
1650 CP(dsbuf, dsbuf32, sem_otime);
1651 CP(dsbuf, dsbuf32, sem_ctime);
1652 error = copyout(&dsbuf32, PTRIN(arg.buf), sizeof(dsbuf32));
1653 break;
1654 }
1655
1656 if (error == 0)
1657 td->td_retval[0] = rval;
1658 return (error);
1659}
1660
1661#endif /* COMPAT_FREEBSD32 */
| 985 struct sem_undo *suptr;
986 struct mtx *sema_mtxp;
987 size_t i, j, k;
988 int error;
989 int do_wakeup, do_undos;
990 unsigned short seq;
991
992#ifdef SEM_DEBUG
993 sops = NULL;
994#endif
995 DPRINTF(("call to semop(%d, %p, %u)\n", semid, sops, nsops));
996
997 if (!prison_allow(td->td_ucred, PR_ALLOW_SYSVIPC))
998 return (ENOSYS);
999
1000 semid = IPCID_TO_IX(semid); /* Convert back to zero origin */
1001
1002 if (semid < 0 || semid >= seminfo.semmni)
1003 return (EINVAL);
1004
1005 /* Allocate memory for sem_ops */
1006 if (nsops <= SMALL_SOPS)
1007 sops = small_sops;
1008 else if (nsops > seminfo.semopm) {
1009 DPRINTF(("too many sops (max=%d, nsops=%d)\n", seminfo.semopm,
1010 nsops));
1011 return (E2BIG);
1012 } else {
1013#ifdef RACCT
1014 if (racct_enable) {
1015 PROC_LOCK(td->td_proc);
1016 if (nsops >
1017 racct_get_available(td->td_proc, RACCT_NSEMOP)) {
1018 PROC_UNLOCK(td->td_proc);
1019 return (E2BIG);
1020 }
1021 PROC_UNLOCK(td->td_proc);
1022 }
1023#endif
1024
1025 sops = malloc(nsops * sizeof(*sops), M_TEMP, M_WAITOK);
1026 }
1027 if ((error = copyin(uap->sops, sops, nsops * sizeof(sops[0]))) != 0) {
1028 DPRINTF(("error = %d from copyin(%p, %p, %d)\n", error,
1029 uap->sops, sops, nsops * sizeof(sops[0])));
1030 if (sops != small_sops)
1031 free(sops, M_SEM);
1032 return (error);
1033 }
1034
1035 semakptr = &sema[semid];
1036 sema_mtxp = &sema_mtx[semid];
1037 mtx_lock(sema_mtxp);
1038 if ((semakptr->u.sem_perm.mode & SEM_ALLOC) == 0) {
1039 error = EINVAL;
1040 goto done2;
1041 }
1042 seq = semakptr->u.sem_perm.seq;
1043 if (seq != IPCID_TO_SEQ(uap->semid)) {
1044 error = EINVAL;
1045 goto done2;
1046 }
1047 /*
1048 * Initial pass thru sops to see what permissions are needed.
1049 * Also perform any checks that don't need repeating on each
1050 * attempt to satisfy the request vector.
1051 */
1052 j = 0; /* permission needed */
1053 do_undos = 0;
1054 for (i = 0; i < nsops; i++) {
1055 sopptr = &sops[i];
1056 if (sopptr->sem_num >= semakptr->u.sem_nsems) {
1057 error = EFBIG;
1058 goto done2;
1059 }
1060 if (sopptr->sem_flg & SEM_UNDO && sopptr->sem_op != 0)
1061 do_undos = 1;
1062 j |= (sopptr->sem_op == 0) ? SEM_R : SEM_A;
1063 }
1064
1065 if ((error = ipcperm(td, &semakptr->u.sem_perm, j))) {
1066 DPRINTF(("error = %d from ipaccess\n", error));
1067 goto done2;
1068 }
1069#ifdef MAC
1070 error = mac_sysvsem_check_semop(td->td_ucred, semakptr, j);
1071 if (error != 0)
1072 goto done2;
1073#endif
1074
1075 /*
1076 * Loop trying to satisfy the vector of requests.
1077 * If we reach a point where we must wait, any requests already
1078 * performed are rolled back and we go to sleep until some other
1079 * process wakes us up. At this point, we start all over again.
1080 *
1081 * This ensures that from the perspective of other tasks, a set
1082 * of requests is atomic (never partially satisfied).
1083 */
1084 for (;;) {
1085 do_wakeup = 0;
1086 error = 0; /* error return if necessary */
1087
1088 for (i = 0; i < nsops; i++) {
1089 sopptr = &sops[i];
1090 semptr = &semakptr->u.sem_base[sopptr->sem_num];
1091
1092 DPRINTF((
1093 "semop: semakptr=%p, sem_base=%p, "
1094 "semptr=%p, sem[%d]=%d : op=%d, flag=%s\n",
1095 semakptr, semakptr->u.sem_base, semptr,
1096 sopptr->sem_num, semptr->semval, sopptr->sem_op,
1097 (sopptr->sem_flg & IPC_NOWAIT) ?
1098 "nowait" : "wait"));
1099
1100 if (sopptr->sem_op < 0) {
1101 if (semptr->semval + sopptr->sem_op < 0) {
1102 DPRINTF(("semop: can't do it now\n"));
1103 break;
1104 } else {
1105 semptr->semval += sopptr->sem_op;
1106 if (semptr->semval == 0 &&
1107 semptr->semzcnt > 0)
1108 do_wakeup = 1;
1109 }
1110 } else if (sopptr->sem_op == 0) {
1111 if (semptr->semval != 0) {
1112 DPRINTF(("semop: not zero now\n"));
1113 break;
1114 }
1115 } else if (semptr->semval + sopptr->sem_op >
1116 seminfo.semvmx) {
1117 error = ERANGE;
1118 break;
1119 } else {
1120 if (semptr->semncnt > 0)
1121 do_wakeup = 1;
1122 semptr->semval += sopptr->sem_op;
1123 }
1124 }
1125
1126 /*
1127 * Did we get through the entire vector?
1128 */
1129 if (i >= nsops)
1130 goto done;
1131
1132 /*
1133 * No ... rollback anything that we've already done
1134 */
1135 DPRINTF(("semop: rollback 0 through %d\n", i-1));
1136 for (j = 0; j < i; j++)
1137 semakptr->u.sem_base[sops[j].sem_num].semval -=
1138 sops[j].sem_op;
1139
1140 /* If we detected an error, return it */
1141 if (error != 0)
1142 goto done2;
1143
1144 /*
1145 * If the request that we couldn't satisfy has the
1146 * NOWAIT flag set then return with EAGAIN.
1147 */
1148 if (sopptr->sem_flg & IPC_NOWAIT) {
1149 error = EAGAIN;
1150 goto done2;
1151 }
1152
1153 if (sopptr->sem_op == 0)
1154 semptr->semzcnt++;
1155 else
1156 semptr->semncnt++;
1157
1158 DPRINTF(("semop: good night!\n"));
1159 error = msleep(semakptr, sema_mtxp, (PZERO - 4) | PCATCH,
1160 "semwait", 0);
1161 DPRINTF(("semop: good morning (error=%d)!\n", error));
1162 /* return code is checked below, after sem[nz]cnt-- */
1163
1164 /*
1165 * Make sure that the semaphore still exists
1166 */
1167 seq = semakptr->u.sem_perm.seq;
1168 if ((semakptr->u.sem_perm.mode & SEM_ALLOC) == 0 ||
1169 seq != IPCID_TO_SEQ(uap->semid)) {
1170 error = EIDRM;
1171 goto done2;
1172 }
1173
1174 /*
1175 * Renew the semaphore's pointer after wakeup since
1176 * during msleep sem_base may have been modified and semptr
1177 * is not valid any more
1178 */
1179 semptr = &semakptr->u.sem_base[sopptr->sem_num];
1180
1181 /*
1182 * The semaphore is still alive. Readjust the count of
1183 * waiting processes.
1184 */
1185 if (sopptr->sem_op == 0)
1186 semptr->semzcnt--;
1187 else
1188 semptr->semncnt--;
1189
1190 /*
1191 * Is it really morning, or was our sleep interrupted?
1192 * (Delayed check of msleep() return code because we
1193 * need to decrement sem[nz]cnt either way.)
1194 */
1195 if (error != 0) {
1196 error = EINTR;
1197 goto done2;
1198 }
1199 DPRINTF(("semop: good morning!\n"));
1200 }
1201
1202done:
1203 /*
1204 * Process any SEM_UNDO requests.
1205 */
1206 if (do_undos) {
1207 SEMUNDO_LOCK();
1208 suptr = NULL;
1209 for (i = 0; i < nsops; i++) {
1210 /*
1211 * We only need to deal with SEM_UNDO's for non-zero
1212 * op's.
1213 */
1214 int adjval;
1215
1216 if ((sops[i].sem_flg & SEM_UNDO) == 0)
1217 continue;
1218 adjval = sops[i].sem_op;
1219 if (adjval == 0)
1220 continue;
1221 error = semundo_adjust(td, &suptr, semid, seq,
1222 sops[i].sem_num, -adjval);
1223 if (error == 0)
1224 continue;
1225
1226 /*
1227 * Oh-Oh! We ran out of either sem_undo's or undo's.
1228 * Rollback the adjustments to this point and then
1229 * rollback the semaphore ups and down so we can return
1230 * with an error with all structures restored. We
1231 * rollback the undo's in the exact reverse order that
1232 * we applied them. This guarantees that we won't run
1233 * out of space as we roll things back out.
1234 */
1235 for (j = 0; j < i; j++) {
1236 k = i - j - 1;
1237 if ((sops[k].sem_flg & SEM_UNDO) == 0)
1238 continue;
1239 adjval = sops[k].sem_op;
1240 if (adjval == 0)
1241 continue;
1242 if (semundo_adjust(td, &suptr, semid, seq,
1243 sops[k].sem_num, adjval) != 0)
1244 panic("semop - can't undo undos");
1245 }
1246
1247 for (j = 0; j < nsops; j++)
1248 semakptr->u.sem_base[sops[j].sem_num].semval -=
1249 sops[j].sem_op;
1250
1251 DPRINTF(("error = %d from semundo_adjust\n", error));
1252 SEMUNDO_UNLOCK();
1253 goto done2;
1254 } /* loop through the sops */
1255 SEMUNDO_UNLOCK();
1256 } /* if (do_undos) */
1257
1258 /* We're definitely done - set the sempid's and time */
1259 for (i = 0; i < nsops; i++) {
1260 sopptr = &sops[i];
1261 semptr = &semakptr->u.sem_base[sopptr->sem_num];
1262 semptr->sempid = td->td_proc->p_pid;
1263 }
1264 semakptr->u.sem_otime = time_second;
1265
1266 /*
1267 * Do a wakeup if any semaphore was up'd whilst something was
1268 * sleeping on it.
1269 */
1270 if (do_wakeup) {
1271 DPRINTF(("semop: doing wakeup\n"));
1272 wakeup(semakptr);
1273 DPRINTF(("semop: back from wakeup\n"));
1274 }
1275 DPRINTF(("semop: done\n"));
1276 td->td_retval[0] = 0;
1277done2:
1278 mtx_unlock(sema_mtxp);
1279 if (sops != small_sops)
1280 free(sops, M_SEM);
1281 return (error);
1282}
1283
1284/*
1285 * Go through the undo structures for this process and apply the adjustments to
1286 * semaphores.
1287 */
1288static void
1289semexit_myhook(void *arg, struct proc *p)
1290{
1291 struct sem_undo *suptr;
1292 struct semid_kernel *semakptr;
1293 struct mtx *sema_mtxp;
1294 int semid, semnum, adjval, ix;
1295 unsigned short seq;
1296
1297 /*
1298 * Go through the chain of undo vectors looking for one
1299 * associated with this process.
1300 */
1301 SEMUNDO_LOCK();
1302 LIST_FOREACH(suptr, &semu_list, un_next) {
1303 if (suptr->un_proc == p)
1304 break;
1305 }
1306 if (suptr == NULL) {
1307 SEMUNDO_UNLOCK();
1308 return;
1309 }
1310 LIST_REMOVE(suptr, un_next);
1311
1312 DPRINTF(("proc @%p has undo structure with %d entries\n", p,
1313 suptr->un_cnt));
1314
1315 /*
1316 * If there are any active undo elements then process them.
1317 */
1318 if (suptr->un_cnt > 0) {
1319 SEMUNDO_UNLOCK();
1320 for (ix = 0; ix < suptr->un_cnt; ix++) {
1321 semid = suptr->un_ent[ix].un_id;
1322 semnum = suptr->un_ent[ix].un_num;
1323 adjval = suptr->un_ent[ix].un_adjval;
1324 seq = suptr->un_ent[ix].un_seq;
1325 semakptr = &sema[semid];
1326 sema_mtxp = &sema_mtx[semid];
1327
1328 mtx_lock(sema_mtxp);
1329 if ((semakptr->u.sem_perm.mode & SEM_ALLOC) == 0 ||
1330 (semakptr->u.sem_perm.seq != seq)) {
1331 mtx_unlock(sema_mtxp);
1332 continue;
1333 }
1334 if (semnum >= semakptr->u.sem_nsems)
1335 panic("semexit - semnum out of range");
1336
1337 DPRINTF((
1338 "semexit: %p id=%d num=%d(adj=%d) ; sem=%d\n",
1339 suptr->un_proc, suptr->un_ent[ix].un_id,
1340 suptr->un_ent[ix].un_num,
1341 suptr->un_ent[ix].un_adjval,
1342 semakptr->u.sem_base[semnum].semval));
1343
1344 if (adjval < 0 && semakptr->u.sem_base[semnum].semval <
1345 -adjval)
1346 semakptr->u.sem_base[semnum].semval = 0;
1347 else
1348 semakptr->u.sem_base[semnum].semval += adjval;
1349
1350 wakeup(semakptr);
1351 DPRINTF(("semexit: back from wakeup\n"));
1352 mtx_unlock(sema_mtxp);
1353 }
1354 SEMUNDO_LOCK();
1355 }
1356
1357 /*
1358 * Deallocate the undo vector.
1359 */
1360 DPRINTF(("removing vector\n"));
1361 suptr->un_proc = NULL;
1362 suptr->un_cnt = 0;
1363 LIST_INSERT_HEAD(&semu_free_list, suptr, un_next);
1364 SEMUNDO_UNLOCK();
1365}
1366
1367static int
1368sysctl_sema(SYSCTL_HANDLER_ARGS)
1369{
1370
1371 return (SYSCTL_OUT(req, sema,
1372 sizeof(struct semid_kernel) * seminfo.semmni));
1373}
1374
1375#if defined(COMPAT_FREEBSD4) || defined(COMPAT_FREEBSD5) || \
1376 defined(COMPAT_FREEBSD6) || defined(COMPAT_FREEBSD7)
1377
1378/* XXX casting to (sy_call_t *) is bogus, as usual. */
1379static sy_call_t *semcalls[] = {
1380 (sy_call_t *)freebsd7___semctl, (sy_call_t *)sys_semget,
1381 (sy_call_t *)sys_semop
1382};
1383
1384/*
1385 * Entry point for all SEM calls.
1386 */
1387int
1388sys_semsys(td, uap)
1389 struct thread *td;
1390 /* XXX actually varargs. */
1391 struct semsys_args /* {
1392 int which;
1393 int a2;
1394 int a3;
1395 int a4;
1396 int a5;
1397 } */ *uap;
1398{
1399 int error;
1400
1401 if (!prison_allow(td->td_ucred, PR_ALLOW_SYSVIPC))
1402 return (ENOSYS);
1403 if (uap->which < 0 ||
1404 uap->which >= sizeof(semcalls)/sizeof(semcalls[0]))
1405 return (EINVAL);
1406 error = (*semcalls[uap->which])(td, &uap->a2);
1407 return (error);
1408}
1409
1410#ifndef CP
1411#define CP(src, dst, fld) do { (dst).fld = (src).fld; } while (0)
1412#endif
1413
1414#ifndef _SYS_SYSPROTO_H_
1415struct freebsd7___semctl_args {
1416 int semid;
1417 int semnum;
1418 int cmd;
1419 union semun_old *arg;
1420};
1421#endif
1422int
1423freebsd7___semctl(struct thread *td, struct freebsd7___semctl_args *uap)
1424{
1425 struct semid_ds_old dsold;
1426 struct semid_ds dsbuf;
1427 union semun_old arg;
1428 union semun semun;
1429 register_t rval;
1430 int error;
1431
1432 switch (uap->cmd) {
1433 case SEM_STAT:
1434 case IPC_SET:
1435 case IPC_STAT:
1436 case GETALL:
1437 case SETVAL:
1438 case SETALL:
1439 error = copyin(uap->arg, &arg, sizeof(arg));
1440 if (error)
1441 return (error);
1442 break;
1443 }
1444
1445 switch (uap->cmd) {
1446 case SEM_STAT:
1447 case IPC_STAT:
1448 semun.buf = &dsbuf;
1449 break;
1450 case IPC_SET:
1451 error = copyin(arg.buf, &dsold, sizeof(dsold));
1452 if (error)
1453 return (error);
1454 ipcperm_old2new(&dsold.sem_perm, &dsbuf.sem_perm);
1455 CP(dsold, dsbuf, sem_base);
1456 CP(dsold, dsbuf, sem_nsems);
1457 CP(dsold, dsbuf, sem_otime);
1458 CP(dsold, dsbuf, sem_ctime);
1459 semun.buf = &dsbuf;
1460 break;
1461 case GETALL:
1462 case SETALL:
1463 semun.array = arg.array;
1464 break;
1465 case SETVAL:
1466 semun.val = arg.val;
1467 break;
1468 }
1469
1470 error = kern_semctl(td, uap->semid, uap->semnum, uap->cmd, &semun,
1471 &rval);
1472 if (error)
1473 return (error);
1474
1475 switch (uap->cmd) {
1476 case SEM_STAT:
1477 case IPC_STAT:
1478 bzero(&dsold, sizeof(dsold));
1479 ipcperm_new2old(&dsbuf.sem_perm, &dsold.sem_perm);
1480 CP(dsbuf, dsold, sem_base);
1481 CP(dsbuf, dsold, sem_nsems);
1482 CP(dsbuf, dsold, sem_otime);
1483 CP(dsbuf, dsold, sem_ctime);
1484 error = copyout(&dsold, arg.buf, sizeof(dsold));
1485 break;
1486 }
1487
1488 if (error == 0)
1489 td->td_retval[0] = rval;
1490 return (error);
1491}
1492
1493#endif /* COMPAT_FREEBSD{4,5,6,7} */
1494
1495#ifdef COMPAT_FREEBSD32
1496
1497int
1498freebsd32_semsys(struct thread *td, struct freebsd32_semsys_args *uap)
1499{
1500
1501#if defined(COMPAT_FREEBSD4) || defined(COMPAT_FREEBSD5) || \
1502 defined(COMPAT_FREEBSD6) || defined(COMPAT_FREEBSD7)
1503 switch (uap->which) {
1504 case 0:
1505 return (freebsd7_freebsd32_semctl(td,
1506 (struct freebsd7_freebsd32_semctl_args *)&uap->a2));
1507 default:
1508 return (sys_semsys(td, (struct semsys_args *)uap));
1509 }
1510#else
1511 return (nosys(td, NULL));
1512#endif
1513}
1514
1515#if defined(COMPAT_FREEBSD4) || defined(COMPAT_FREEBSD5) || \
1516 defined(COMPAT_FREEBSD6) || defined(COMPAT_FREEBSD7)
1517int
1518freebsd7_freebsd32_semctl(struct thread *td,
1519 struct freebsd7_freebsd32_semctl_args *uap)
1520{
1521 struct semid_ds32_old dsbuf32;
1522 struct semid_ds dsbuf;
1523 union semun semun;
1524 union semun32 arg;
1525 register_t rval;
1526 int error;
1527
1528 switch (uap->cmd) {
1529 case SEM_STAT:
1530 case IPC_SET:
1531 case IPC_STAT:
1532 case GETALL:
1533 case SETVAL:
1534 case SETALL:
1535 error = copyin(uap->arg, &arg, sizeof(arg));
1536 if (error)
1537 return (error);
1538 break;
1539 }
1540
1541 switch (uap->cmd) {
1542 case SEM_STAT:
1543 case IPC_STAT:
1544 semun.buf = &dsbuf;
1545 break;
1546 case IPC_SET:
1547 error = copyin(PTRIN(arg.buf), &dsbuf32, sizeof(dsbuf32));
1548 if (error)
1549 return (error);
1550 freebsd32_ipcperm_old_in(&dsbuf32.sem_perm, &dsbuf.sem_perm);
1551 PTRIN_CP(dsbuf32, dsbuf, sem_base);
1552 CP(dsbuf32, dsbuf, sem_nsems);
1553 CP(dsbuf32, dsbuf, sem_otime);
1554 CP(dsbuf32, dsbuf, sem_ctime);
1555 semun.buf = &dsbuf;
1556 break;
1557 case GETALL:
1558 case SETALL:
1559 semun.array = PTRIN(arg.array);
1560 break;
1561 case SETVAL:
1562 semun.val = arg.val;
1563 break;
1564 }
1565
1566 error = kern_semctl(td, uap->semid, uap->semnum, uap->cmd, &semun,
1567 &rval);
1568 if (error)
1569 return (error);
1570
1571 switch (uap->cmd) {
1572 case SEM_STAT:
1573 case IPC_STAT:
1574 bzero(&dsbuf32, sizeof(dsbuf32));
1575 freebsd32_ipcperm_old_out(&dsbuf.sem_perm, &dsbuf32.sem_perm);
1576 PTROUT_CP(dsbuf, dsbuf32, sem_base);
1577 CP(dsbuf, dsbuf32, sem_nsems);
1578 CP(dsbuf, dsbuf32, sem_otime);
1579 CP(dsbuf, dsbuf32, sem_ctime);
1580 error = copyout(&dsbuf32, PTRIN(arg.buf), sizeof(dsbuf32));
1581 break;
1582 }
1583
1584 if (error == 0)
1585 td->td_retval[0] = rval;
1586 return (error);
1587}
1588#endif
1589
1590int
1591freebsd32_semctl(struct thread *td, struct freebsd32_semctl_args *uap)
1592{
1593 struct semid_ds32 dsbuf32;
1594 struct semid_ds dsbuf;
1595 union semun semun;
1596 union semun32 arg;
1597 register_t rval;
1598 int error;
1599
1600 switch (uap->cmd) {
1601 case SEM_STAT:
1602 case IPC_SET:
1603 case IPC_STAT:
1604 case GETALL:
1605 case SETVAL:
1606 case SETALL:
1607 error = copyin(uap->arg, &arg, sizeof(arg));
1608 if (error)
1609 return (error);
1610 break;
1611 }
1612
1613 switch (uap->cmd) {
1614 case SEM_STAT:
1615 case IPC_STAT:
1616 semun.buf = &dsbuf;
1617 break;
1618 case IPC_SET:
1619 error = copyin(PTRIN(arg.buf), &dsbuf32, sizeof(dsbuf32));
1620 if (error)
1621 return (error);
1622 freebsd32_ipcperm_in(&dsbuf32.sem_perm, &dsbuf.sem_perm);
1623 PTRIN_CP(dsbuf32, dsbuf, sem_base);
1624 CP(dsbuf32, dsbuf, sem_nsems);
1625 CP(dsbuf32, dsbuf, sem_otime);
1626 CP(dsbuf32, dsbuf, sem_ctime);
1627 semun.buf = &dsbuf;
1628 break;
1629 case GETALL:
1630 case SETALL:
1631 semun.array = PTRIN(arg.array);
1632 break;
1633 case SETVAL:
1634 semun.val = arg.val;
1635 break;
1636 }
1637
1638 error = kern_semctl(td, uap->semid, uap->semnum, uap->cmd, &semun,
1639 &rval);
1640 if (error)
1641 return (error);
1642
1643 switch (uap->cmd) {
1644 case SEM_STAT:
1645 case IPC_STAT:
1646 bzero(&dsbuf32, sizeof(dsbuf32));
1647 freebsd32_ipcperm_out(&dsbuf.sem_perm, &dsbuf32.sem_perm);
1648 PTROUT_CP(dsbuf, dsbuf32, sem_base);
1649 CP(dsbuf, dsbuf32, sem_nsems);
1650 CP(dsbuf, dsbuf32, sem_otime);
1651 CP(dsbuf, dsbuf32, sem_ctime);
1652 error = copyout(&dsbuf32, PTRIN(arg.buf), sizeof(dsbuf32));
1653 break;
1654 }
1655
1656 if (error == 0)
1657 td->td_retval[0] = rval;
1658 return (error);
1659}
1660
1661#endif /* COMPAT_FREEBSD32 */
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