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Fix "ls: not found" problem during buildworld. mdate.sh script
[dragonfly.git] / sys / kern / sysv_sem.c
blob14c4cdf599644f231bd63858257649ed467fc522
1 /* $FreeBSD: src/sys/kern/sysv_sem.c,v 1.69 2004/03/17 09:37:13 cperciva Exp $ */
2 /* $DragonFly: src/sys/kern/sysv_sem.c,v 1.14 2004/05/26 14:12:34 hmp Exp $ */
3
4 /*
5 * Implementation of SVID semaphores
6 *
7 * Author: Daniel Boulet
8 *
9 * This software is provided ``AS IS'' without any warranties of any kind.
10 */
11
12 #include "opt_sysvipc.h"
13
14 #include <sys/param.h>
15 #include <sys/systm.h>
16 #include <sys/sysproto.h>
17 #include <sys/kernel.h>
18 #include <sys/proc.h>
19 #include <sys/sem.h>
20 #include <sys/sysent.h>
21 #include <sys/sysctl.h>
22 #include <sys/malloc.h>
23 #include <sys/jail.h>
24
25 static MALLOC_DEFINE(M_SEM, "sem", "SVID compatible semaphores");
26
27 static void seminit (void *);
28
29 #ifndef _SYS_SYSPROTO_H_
30 struct __semctl_args;
31 int __semctl (struct proc *p, struct __semctl_args *uap);
32 struct semget_args;
33 int semget (struct proc *p, struct semget_args *uap);
34 struct semop_args;
35 int semop (struct proc *p, struct semop_args *uap);
36 #endif
37
38 static struct sem_undo *semu_alloc (struct proc *p);
39 static int semundo_adjust (struct proc *p, struct sem_undo **supptr,
40 int semid, int semnum, int adjval);
41 static void semundo_clear (int semid, int semnum);
42
43 /* XXX casting to (sy_call_t *) is bogus, as usual. */
44 static sy_call_t *semcalls[] = {
45 (sy_call_t *)__semctl, (sy_call_t *)semget,
46 (sy_call_t *)semop
47 };
48
49 static int semtot = 0;
50 static struct semid_ds *sema; /* semaphore id pool */
51 static struct sem *sem; /* semaphore pool */
52 static struct sem_undo *semu_list; /* list of active undo structures */
53 static int *semu; /* undo structure pool */
54
55 struct sem {
56 u_short semval; /* semaphore value */
57 pid_t sempid; /* pid of last operation */
58 u_short semncnt; /* # awaiting semval > cval */
59 u_short semzcnt; /* # awaiting semval = 0 */
60 };
61
62 /*
63 * Undo structure (one per process)
64 */
65 struct sem_undo {
66 struct sem_undo *un_next; /* ptr to next active undo structure */
67 struct proc *un_proc; /* owner of this structure */
68 short un_cnt; /* # of active entries */
69 struct undo {
70 short un_adjval; /* adjust on exit values */
71 short un_num; /* semaphore # */
72 int un_id; /* semid */
73 } un_ent[1]; /* undo entries */
74 };
75
76 /*
77 * Configuration parameters
78 */
79 #ifndef SEMMNI
80 #define SEMMNI 10 /* # of semaphore identifiers */
81 #endif
82 #ifndef SEMMNS
83 #define SEMMNS 60 /* # of semaphores in system */
84 #endif
85 #ifndef SEMUME
86 #define SEMUME 10 /* max # of undo entries per process */
87 #endif
88 #ifndef SEMMNU
89 #define SEMMNU 30 /* # of undo structures in system */
90 #endif
91
92 /* shouldn't need tuning */
93 #ifndef SEMMAP
94 #define SEMMAP 30 /* # of entries in semaphore map */
95 #endif
96 #ifndef SEMMSL
97 #define SEMMSL SEMMNS /* max # of semaphores per id */
98 #endif
99 #ifndef SEMOPM
100 #define SEMOPM 100 /* max # of operations per semop call */
101 #endif
102
103 #define SEMVMX 32767 /* semaphore maximum value */
104 #define SEMAEM 16384 /* adjust on exit max value */
105
106 /*
107 * Due to the way semaphore memory is allocated, we have to ensure that
108 * SEMUSZ is properly aligned.
109 */
110
111 #define SEM_ALIGN(bytes) (((bytes) + (sizeof(long) - 1)) & ~(sizeof(long) - 1))
112
113 /* actual size of an undo structure */
114 #define SEMUSZ SEM_ALIGN(offsetof(struct sem_undo, un_ent[SEMUME]))
115
116 /*
117 * Macro to find a particular sem_undo vector
118 */
119 #define SEMU(ix) ((struct sem_undo *)(((intptr_t)semu)+ix * seminfo.semusz))
120
121 /*
122 * semaphore info struct
123 */
124 struct seminfo seminfo = {
125 SEMMAP, /* # of entries in semaphore map */
126 SEMMNI, /* # of semaphore identifiers */
127 SEMMNS, /* # of semaphores in system */
128 SEMMNU, /* # of undo structures in system */
129 SEMMSL, /* max # of semaphores per id */
130 SEMOPM, /* max # of operations per semop call */
131 SEMUME, /* max # of undo entries per process */
132 SEMUSZ, /* size in bytes of undo structure */
133 SEMVMX, /* semaphore maximum value */
134 SEMAEM /* adjust on exit max value */
135 };
136
137 TUNABLE_INT("kern.ipc.semmap", &seminfo.semmap);
138 TUNABLE_INT("kern.ipc.semmni", &seminfo.semmni);
139 TUNABLE_INT("kern.ipc.semmns", &seminfo.semmns);
140 TUNABLE_INT("kern.ipc.semmnu", &seminfo.semmnu);
141 TUNABLE_INT("kern.ipc.semmsl", &seminfo.semmsl);
142 TUNABLE_INT("kern.ipc.semopm", &seminfo.semopm);
143 TUNABLE_INT("kern.ipc.semume", &seminfo.semume);
144 TUNABLE_INT("kern.ipc.semusz", &seminfo.semusz);
145 TUNABLE_INT("kern.ipc.semvmx", &seminfo.semvmx);
146 TUNABLE_INT("kern.ipc.semaem", &seminfo.semaem);
147
148 SYSCTL_INT(_kern_ipc, OID_AUTO, semmap, CTLFLAG_RW, &seminfo.semmap, 0, "");
149 SYSCTL_INT(_kern_ipc, OID_AUTO, semmni, CTLFLAG_RD, &seminfo.semmni, 0, "");
150 SYSCTL_INT(_kern_ipc, OID_AUTO, semmns, CTLFLAG_RD, &seminfo.semmns, 0, "");
151 SYSCTL_INT(_kern_ipc, OID_AUTO, semmnu, CTLFLAG_RD, &seminfo.semmnu, 0, "");
152 SYSCTL_INT(_kern_ipc, OID_AUTO, semmsl, CTLFLAG_RW, &seminfo.semmsl, 0, "");
153 SYSCTL_INT(_kern_ipc, OID_AUTO, semopm, CTLFLAG_RD, &seminfo.semopm, 0, "");
154 SYSCTL_INT(_kern_ipc, OID_AUTO, semume, CTLFLAG_RD, &seminfo.semume, 0, "");
155 SYSCTL_INT(_kern_ipc, OID_AUTO, semusz, CTLFLAG_RD, &seminfo.semusz, 0, "");
156 SYSCTL_INT(_kern_ipc, OID_AUTO, semvmx, CTLFLAG_RW, &seminfo.semvmx, 0, "");
157 SYSCTL_INT(_kern_ipc, OID_AUTO, semaem, CTLFLAG_RW, &seminfo.semaem, 0, "");
158
159 #if 0
160 RO seminfo.semmap /* SEMMAP unused */
161 RO seminfo.semmni
162 RO seminfo.semmns
163 RO seminfo.semmnu /* undo entries per system */
164 RW seminfo.semmsl
165 RO seminfo.semopm /* SEMOPM unused */
166 RO seminfo.semume
167 RO seminfo.semusz /* param - derived from SEMUME for per-proc sizeof */
168 RO seminfo.semvmx /* SEMVMX unused - user param */
169 RO seminfo.semaem /* SEMAEM unused - user param */
170 #endif
171
172 static void
173 seminit(dummy)
174 void *dummy;
175 {
176 int i;
177
178 sem = malloc(sizeof(struct sem) * seminfo.semmns, M_SEM, M_WAITOK);
179 if (sem == NULL)
180 panic("sem is NULL");
181 sema = malloc(sizeof(struct semid_ds) * seminfo.semmni, M_SEM, M_WAITOK);
182 if (sema == NULL)
183 panic("sema is NULL");
184 semu = malloc(seminfo.semmnu * seminfo.semusz, M_SEM, M_WAITOK);
185 if (semu == NULL)
186 panic("semu is NULL");
187
188 for (i = 0; i < seminfo.semmni; i++) {
189 sema[i].sem_base = 0;
190 sema[i].sem_perm.mode = 0;
191 }
192 for (i = 0; i < seminfo.semmnu; i++) {
193 struct sem_undo *suptr = SEMU(i);
194 suptr->un_proc = NULL;
195 }
196 semu_list = NULL;
197 }
198 SYSINIT(sysv_sem, SI_SUB_SYSV_SEM, SI_ORDER_FIRST, seminit, NULL)
199
200 /*
201 * Entry point for all SEM calls
202 *
203 * semsys_args(int which, a2, a3, ...) (VARARGS)
204 */
205 int
206 semsys(struct semsys_args *uap)
207 {
208 struct proc *p = curproc;
209 unsigned int which = (unsigned int)uap->which;
210
211 if (!jail_sysvipc_allowed && p->p_ucred->cr_prison != NULL)
212 return (ENOSYS);
213
214 if (which >= sizeof(semcalls)/sizeof(semcalls[0]))
215 return (EINVAL);
216 bcopy(&uap->a2, &uap->which,
217 sizeof(struct semsys_args) - offsetof(struct semsys_args, a2));
218 return ((*semcalls[which])(uap));
219 }
220
221 /*
222 * Allocate a new sem_undo structure for a process
223 * (returns ptr to structure or NULL if no more room)
224 */
225
226 static struct sem_undo *
227 semu_alloc(p)
228 struct proc *p;
229 {
230 int i;
231 struct sem_undo *suptr;
232 struct sem_undo **supptr;
233 int attempt;
234
235 /*
236 * Try twice to allocate something.
237 * (we'll purge any empty structures after the first pass so
238 * two passes are always enough)
239 */
240
241 for (attempt = 0; attempt < 2; attempt++) {
242 /*
243 * Look for a free structure.
244 * Fill it in and return it if we find one.
245 */
246
247 for (i = 0; i < seminfo.semmnu; i++) {
248 suptr = SEMU(i);
249 if (suptr->un_proc == NULL) {
250 suptr->un_next = semu_list;
251 semu_list = suptr;
252 suptr->un_cnt = 0;
253 suptr->un_proc = p;
254 return(suptr);
255 }
256 }
257
258 /*
259 * We didn't find a free one, if this is the first attempt
260 * then try to free some structures.
261 */
262
263 if (attempt == 0) {
264 /* All the structures are in use - try to free some */
265 int did_something = 0;
266
267 supptr = &semu_list;
268 while ((suptr = *supptr) != NULL) {
269 if (suptr->un_cnt == 0) {
270 suptr->un_proc = NULL;
271 *supptr = suptr->un_next;
272 did_something = 1;
273 } else
274 supptr = &(suptr->un_next);
275 }
276
277 /* If we didn't free anything then just give-up */
278 if (!did_something)
279 return(NULL);
280 } else {
281 /*
282 * The second pass failed even though we freed
283 * something after the first pass!
284 * This is IMPOSSIBLE!
285 */
286 panic("semu_alloc - second attempt failed");
287 }
288 }
289 return (NULL);
290 }
291
292 /*
293 * Adjust a particular entry for a particular proc
294 */
295
296 static int
297 semundo_adjust(p, supptr, semid, semnum, adjval)
298 struct proc *p;
299 struct sem_undo **supptr;
300 int semid, semnum;
301 int adjval;
302 {
303 struct sem_undo *suptr;
304 struct undo *sunptr;
305 int i;
306
307 /* Look for and remember the sem_undo if the caller doesn't provide
308 it */
309
310 suptr = *supptr;
311 if (suptr == NULL) {
312 for (suptr = semu_list; suptr != NULL;
313 suptr = suptr->un_next) {
314 if (suptr->un_proc == p) {
315 *supptr = suptr;
316 break;
317 }
318 }
319 if (suptr == NULL) {
320 if (adjval == 0)
321 return(0);
322 suptr = semu_alloc(p);
323 if (suptr == NULL)
324 return(ENOSPC);
325 *supptr = suptr;
326 }
327 }
328
329 /*
330 * Look for the requested entry and adjust it (delete if adjval becomes
331 * 0).
332 */
333 sunptr = &suptr->un_ent[0];
334 for (i = 0; i < suptr->un_cnt; i++, sunptr++) {
335 if (sunptr->un_id != semid || sunptr->un_num != semnum)
336 continue;
337 if (adjval == 0)
338 sunptr->un_adjval = 0;
339 else
340 sunptr->un_adjval += adjval;
341 if (sunptr->un_adjval == 0) {
342 suptr->un_cnt--;
343 if (i < suptr->un_cnt)
344 suptr->un_ent[i] =
345 suptr->un_ent[suptr->un_cnt];
346 }
347 return(0);
348 }
349
350 /* Didn't find the right entry - create it */
351 if (adjval == 0)
352 return(0);
353 if (suptr->un_cnt != seminfo.semume) {
354 sunptr = &suptr->un_ent[suptr->un_cnt];
355 suptr->un_cnt++;
356 sunptr->un_adjval = adjval;
357 sunptr->un_id = semid; sunptr->un_num = semnum;
358 } else
359 return(EINVAL);
360 return(0);
361 }
362
363 static void
364 semundo_clear(semid, semnum)
365 int semid, semnum;
366 {
367 struct sem_undo *suptr;
368
369 for (suptr = semu_list; suptr != NULL; suptr = suptr->un_next) {
370 struct undo *sunptr = &suptr->un_ent[0];
371 int i = 0;
372
373 while (i < suptr->un_cnt) {
374 if (sunptr->un_id == semid) {
375 if (semnum == -1 || sunptr->un_num == semnum) {
376 suptr->un_cnt--;
377 if (i < suptr->un_cnt) {
378 suptr->un_ent[i] =
379 suptr->un_ent[suptr->un_cnt];
380 continue;
381 }
382 }
383 if (semnum != -1)
384 break;
385 }
386 i++, sunptr++;
387 }
388 }
389 }
390
391 /*
392 * Note that the user-mode half of this passes a union, not a pointer
393 */
394
395 int
396 __semctl(struct __semctl_args *uap)
397 {
398 struct proc *p = curproc;
399 int semid = uap->semid;
400 int semnum = uap->semnum;
401 int cmd = uap->cmd;
402 union semun *arg = uap->arg;
403 union semun real_arg;
404 struct ucred *cred = p->p_ucred;
405 int i, rval, eval;
406 struct semid_ds sbuf;
407 struct semid_ds *semaptr;
408
409 #ifdef SEM_DEBUG
410 printf("call to semctl(%d, %d, %d, 0x%x)\n", semid, semnum, cmd, arg);
411 #endif
412
413 if (!jail_sysvipc_allowed && p->p_ucred->cr_prison != NULL)
414 return (ENOSYS);
415
416 semid = IPCID_TO_IX(semid);
417 if (semid < 0 || semid >= seminfo.semmni)
418 return(EINVAL);
419
420 semaptr = &sema[semid];
421 if ((semaptr->sem_perm.mode & SEM_ALLOC) == 0 ||
422 semaptr->sem_perm.seq != IPCID_TO_SEQ(uap->semid))
423 return(EINVAL);
424
425 eval = 0;
426 rval = 0;
427
428 switch (cmd) {
429 case IPC_RMID:
430 if ((eval = ipcperm(p, &semaptr->sem_perm, IPC_M)))
431 return(eval);
432 semaptr->sem_perm.cuid = cred->cr_uid;
433 semaptr->sem_perm.uid = cred->cr_uid;
434 semtot -= semaptr->sem_nsems;
435 for (i = semaptr->sem_base - sem; i < semtot; i++)
436 sem[i] = sem[i + semaptr->sem_nsems];
437 for (i = 0; i < seminfo.semmni; i++) {
438 if ((sema[i].sem_perm.mode & SEM_ALLOC) &&
439 sema[i].sem_base > semaptr->sem_base)
440 sema[i].sem_base -= semaptr->sem_nsems;
441 }
442 semaptr->sem_perm.mode = 0;
443 semundo_clear(semid, -1);
444 wakeup((caddr_t)semaptr);
445 break;
446
447 case IPC_SET:
448 if ((eval = ipcperm(p, &semaptr->sem_perm, IPC_M)))
449 return(eval);
450 if ((eval = copyin(arg, &real_arg, sizeof(real_arg))) != 0)
451 return(eval);
452 if ((eval = copyin(real_arg.buf, (caddr_t)&sbuf,
453 sizeof(sbuf))) != 0)
454 return(eval);
455 semaptr->sem_perm.uid = sbuf.sem_perm.uid;
456 semaptr->sem_perm.gid = sbuf.sem_perm.gid;
457 semaptr->sem_perm.mode = (semaptr->sem_perm.mode & ~0777) |
458 (sbuf.sem_perm.mode & 0777);
459 semaptr->sem_ctime = time_second;
460 break;
461
462 case IPC_STAT:
463 if ((eval = ipcperm(p, &semaptr->sem_perm, IPC_R)))
464 return(eval);
465 if ((eval = copyin(arg, &real_arg, sizeof(real_arg))) != 0)
466 return(eval);
467 eval = copyout((caddr_t)semaptr, real_arg.buf,
468 sizeof(struct semid_ds));
469 break;
470
471 case GETNCNT:
472 if ((eval = ipcperm(p, &semaptr->sem_perm, IPC_R)))
473 return(eval);
474 if (semnum < 0 || semnum >= semaptr->sem_nsems)
475 return(EINVAL);
476 rval = semaptr->sem_base[semnum].semncnt;
477 break;
478
479 case GETPID:
480 if ((eval = ipcperm(p, &semaptr->sem_perm, IPC_R)))
481 return(eval);
482 if (semnum < 0 || semnum >= semaptr->sem_nsems)
483 return(EINVAL);
484 rval = semaptr->sem_base[semnum].sempid;
485 break;
486
487 case GETVAL:
488 if ((eval = ipcperm(p, &semaptr->sem_perm, IPC_R)))
489 return(eval);
490 if (semnum < 0 || semnum >= semaptr->sem_nsems)
491 return(EINVAL);
492 rval = semaptr->sem_base[semnum].semval;
493 break;
494
495 case GETALL:
496 if ((eval = ipcperm(p, &semaptr->sem_perm, IPC_R)))
497 return(eval);
498 if ((eval = copyin(arg, &real_arg, sizeof(real_arg))) != 0)
499 return(eval);
500 for (i = 0; i < semaptr->sem_nsems; i++) {
501 eval = copyout((caddr_t)&semaptr->sem_base[i].semval,
502 &real_arg.array[i], sizeof(real_arg.array[0]));
503 if (eval != 0)
504 break;
505 }
506 break;
507
508 case GETZCNT:
509 if ((eval = ipcperm(p, &semaptr->sem_perm, IPC_R)))
510 return(eval);
511 if (semnum < 0 || semnum >= semaptr->sem_nsems)
512 return(EINVAL);
513 rval = semaptr->sem_base[semnum].semzcnt;
514 break;
515
516 case SETVAL:
517 if ((eval = ipcperm(p, &semaptr->sem_perm, IPC_W)))
518 return(eval);
519 if (semnum < 0 || semnum >= semaptr->sem_nsems)
520 return(EINVAL);
521 if ((eval = copyin(arg, &real_arg, sizeof(real_arg))) != 0)
522 return(eval);
523 semaptr->sem_base[semnum].semval = real_arg.val;
524 semundo_clear(semid, semnum);
525 wakeup((caddr_t)semaptr);
526 break;
527
528 case SETALL:
529 if ((eval = ipcperm(p, &semaptr->sem_perm, IPC_W)))
530 return(eval);
531 if ((eval = copyin(arg, &real_arg, sizeof(real_arg))) != 0)
532 return(eval);
533 for (i = 0; i < semaptr->sem_nsems; i++) {
534 eval = copyin(&real_arg.array[i],
535 (caddr_t)&semaptr->sem_base[i].semval,
536 sizeof(real_arg.array[0]));
537 if (eval != 0)
538 break;
539 }
540 semundo_clear(semid, -1);
541 wakeup((caddr_t)semaptr);
542 break;
543
544 default:
545 return(EINVAL);
546 }
547
548 if (eval == 0)
549 uap->sysmsg_result = rval;
550 return(eval);
551 }
552
553 int
554 semget(struct semget_args *uap)
555 {
556 struct proc *p = curproc;
557 int semid, eval;
558 int key = uap->key;
559 int nsems = uap->nsems;
560 int semflg = uap->semflg;
561 struct ucred *cred = p->p_ucred;
562
563 #ifdef SEM_DEBUG
564 printf("semget(0x%x, %d, 0%o)\n", key, nsems, semflg);
565 #endif
566
567 if (!jail_sysvipc_allowed && p->p_ucred->cr_prison != NULL)
568 return (ENOSYS);
569
570 if (key != IPC_PRIVATE) {
571 for (semid = 0; semid < seminfo.semmni; semid++) {
572 if ((sema[semid].sem_perm.mode & SEM_ALLOC) &&
573 sema[semid].sem_perm.key == key)
574 break;
575 }
576 if (semid < seminfo.semmni) {
577 #ifdef SEM_DEBUG
578 printf("found public key\n");
579 #endif
580 if ((eval = ipcperm(p, &sema[semid].sem_perm,
581 semflg & 0700)))
582 return(eval);
583 if (nsems > 0 && sema[semid].sem_nsems < nsems) {
584 #ifdef SEM_DEBUG
585 printf("too small\n");
586 #endif
587 return(EINVAL);
588 }
589 if ((semflg & IPC_CREAT) && (semflg & IPC_EXCL)) {
590 #ifdef SEM_DEBUG
591 printf("not exclusive\n");
592 #endif
593 return(EEXIST);
594 }
595 goto found;
596 }
597 }
598
599 #ifdef SEM_DEBUG
600 printf("need to allocate the semid_ds\n");
601 #endif
602 if (key == IPC_PRIVATE || (semflg & IPC_CREAT)) {
603 if (nsems <= 0 || nsems > seminfo.semmsl) {
604 #ifdef SEM_DEBUG
605 printf("nsems out of range (0<%d<=%d)\n", nsems,
606 seminfo.semmsl);
607 #endif
608 return(EINVAL);
609 }
610 if (nsems > seminfo.semmns - semtot) {
611 #ifdef SEM_DEBUG
612 printf("not enough semaphores left (need %d, got %d)\n",
613 nsems, seminfo.semmns - semtot);
614 #endif
615 return(ENOSPC);
616 }
617 for (semid = 0; semid < seminfo.semmni; semid++) {
618 if ((sema[semid].sem_perm.mode & SEM_ALLOC) == 0)
619 break;
620 }
621 if (semid == seminfo.semmni) {
622 #ifdef SEM_DEBUG
623 printf("no more semid_ds's available\n");
624 #endif
625 return(ENOSPC);
626 }
627 #ifdef SEM_DEBUG
628 printf("semid %d is available\n", semid);
629 #endif
630 sema[semid].sem_perm.key = key;
631 sema[semid].sem_perm.cuid = cred->cr_uid;
632 sema[semid].sem_perm.uid = cred->cr_uid;
633 sema[semid].sem_perm.cgid = cred->cr_gid;
634 sema[semid].sem_perm.gid = cred->cr_gid;
635 sema[semid].sem_perm.mode = (semflg & 0777) | SEM_ALLOC;
636 sema[semid].sem_perm.seq =
637 (sema[semid].sem_perm.seq + 1) & 0x7fff;
638 sema[semid].sem_nsems = nsems;
639 sema[semid].sem_otime = 0;
640 sema[semid].sem_ctime = time_second;
641 sema[semid].sem_base = &sem[semtot];
642 semtot += nsems;
643 bzero(sema[semid].sem_base,
644 sizeof(sema[semid].sem_base[0])*nsems);
645 #ifdef SEM_DEBUG
646 printf("sembase = 0x%x, next = 0x%x\n", sema[semid].sem_base,
647 &sem[semtot]);
648 #endif
649 } else {
650 #ifdef SEM_DEBUG
651 printf("didn't find it and wasn't asked to create it\n");
652 #endif
653 return(ENOENT);
654 }
655
656 found:
657 uap->sysmsg_result = IXSEQ_TO_IPCID(semid, sema[semid].sem_perm);
658 return(0);
659 }
660
661 int
662 semop(struct semop_args *uap)
663 {
664 struct proc *p = curproc;
665 int semid = uap->semid;
666 u_int nsops = uap->nsops;
667 struct sembuf sops[MAX_SOPS];
668 struct semid_ds *semaptr;
669 struct sembuf *sopptr;
670 struct sem *semptr;
671 struct sem_undo *suptr = NULL;
672 int i, j, eval;
673 int do_wakeup, do_undos;
674
675 #ifdef SEM_DEBUG
676 printf("call to semop(%d, 0x%x, %u)\n", semid, sops, nsops);
677 #endif
678
679 if (!jail_sysvipc_allowed && p->p_ucred->cr_prison != NULL)
680 return (ENOSYS);
681
682 semid = IPCID_TO_IX(semid); /* Convert back to zero origin */
683
684 if (semid < 0 || semid >= seminfo.semmni)
685 return(EINVAL);
686
687 semaptr = &sema[semid];
688 if ((semaptr->sem_perm.mode & SEM_ALLOC) == 0)
689 return(EINVAL);
690 if (semaptr->sem_perm.seq != IPCID_TO_SEQ(uap->semid))
691 return(EINVAL);
692
693 if ((eval = ipcperm(p, &semaptr->sem_perm, IPC_W))) {
694 #ifdef SEM_DEBUG
695 printf("eval = %d from ipaccess\n", eval);
696 #endif
697 return(eval);
698 }
699
700 if (nsops > MAX_SOPS) {
701 #ifdef SEM_DEBUG
702 printf("too many sops (max=%d, nsops=%u)\n", MAX_SOPS, nsops);
703 #endif
704 return(E2BIG);
705 }
706
707 if ((eval = copyin(uap->sops, &sops, nsops * sizeof(sops[0]))) != 0) {
708 #ifdef SEM_DEBUG
709 printf("eval = %d from copyin(%08x, %08x, %u)\n", eval,
710 uap->sops, &sops, nsops * sizeof(sops[0]));
711 #endif
712 return(eval);
713 }
714
715 /*
716 * Loop trying to satisfy the vector of requests.
717 * If we reach a point where we must wait, any requests already
718 * performed are rolled back and we go to sleep until some other
719 * process wakes us up. At this point, we start all over again.
720 *
721 * This ensures that from the perspective of other tasks, a set
722 * of requests is atomic (never partially satisfied).
723 */
724 do_undos = 0;
725
726 for (;;) {
727 do_wakeup = 0;
728
729 for (i = 0; i < nsops; i++) {
730 sopptr = &sops[i];
731
732 if (sopptr->sem_num >= semaptr->sem_nsems)
733 return(EFBIG);
734
735 semptr = &semaptr->sem_base[sopptr->sem_num];
736
737 #ifdef SEM_DEBUG
738 printf("semop: semaptr=%x, sem_base=%x, semptr=%x, sem[%d]=%d : op=%d, flag=%s\n",
739 semaptr, semaptr->sem_base, semptr,
740 sopptr->sem_num, semptr->semval, sopptr->sem_op,
741 (sopptr->sem_flg & IPC_NOWAIT) ? "nowait" : "wait");
742 #endif
743
744 if (sopptr->sem_op < 0) {
745 if (semptr->semval + sopptr->sem_op < 0) {
746 #ifdef SEM_DEBUG
747 printf("semop: can't do it now\n");
748 #endif
749 break;
750 } else {
751 semptr->semval += sopptr->sem_op;
752 if (semptr->semval == 0 &&
753 semptr->semzcnt > 0)
754 do_wakeup = 1;
755 }
756 if (sopptr->sem_flg & SEM_UNDO)
757 do_undos = 1;
758 } else if (sopptr->sem_op == 0) {
759 if (semptr->semval > 0) {
760 #ifdef SEM_DEBUG
761 printf("semop: not zero now\n");
762 #endif
763 break;
764 }
765 } else {
766 if (semptr->semncnt > 0)
767 do_wakeup = 1;
768 semptr->semval += sopptr->sem_op;
769 if (sopptr->sem_flg & SEM_UNDO)
770 do_undos = 1;
771 }
772 }
773
774 /*
775 * Did we get through the entire vector?
776 */
777 if (i >= nsops)
778 goto done;
779
780 /*
781 * No ... rollback anything that we've already done
782 */
783 #ifdef SEM_DEBUG
784 printf("semop: rollback 0 through %d\n", i-1);
785 #endif
786 for (j = 0; j < i; j++)
787 semaptr->sem_base[sops[j].sem_num].semval -=
788 sops[j].sem_op;
789
790 /*
791 * If the request that we couldn't satisfy has the
792 * NOWAIT flag set then return with EAGAIN.
793 */
794 if (sopptr->sem_flg & IPC_NOWAIT)
795 return(EAGAIN);
796
797 if (sopptr->sem_op == 0)
798 semptr->semzcnt++;
799 else
800 semptr->semncnt++;
801
802 #ifdef SEM_DEBUG
803 printf("semop: good night!\n");
804 #endif
805 eval = tsleep((caddr_t)semaptr, PCATCH, "semwait", 0);
806 #ifdef SEM_DEBUG
807 printf("semop: good morning (eval=%d)!\n", eval);
808 #endif
809
810 suptr = NULL; /* sem_undo may have been reallocated */
811
812 /* return code is checked below, after sem[nz]cnt-- */
813
814 /*
815 * Make sure that the semaphore still exists
816 */
817 if ((semaptr->sem_perm.mode & SEM_ALLOC) == 0 ||
818 semaptr->sem_perm.seq != IPCID_TO_SEQ(uap->semid))
819 return(EIDRM);
820
821 /*
822 * The semaphore is still alive. Readjust the count of
823 * waiting processes.
824 */
825 if (sopptr->sem_op == 0)
826 semptr->semzcnt--;
827 else
828 semptr->semncnt--;
829
830 /*
831 * Is it really morning, or was our sleep interrupted?
832 * (Delayed check of msleep() return code because we
833 * need to decrement sem[nz]cnt either way.)
834 */
835 if (eval != 0)
836 return(EINTR);
837 #ifdef SEM_DEBUG
838 printf("semop: good morning!\n");
839 #endif
840 }
841
842 done:
843 /*
844 * Process any SEM_UNDO requests.
845 */
846 if (do_undos) {
847 for (i = 0; i < nsops; i++) {
848 /*
849 * We only need to deal with SEM_UNDO's for non-zero
850 * op's.
851 */
852 int adjval;
853
854 if ((sops[i].sem_flg & SEM_UNDO) == 0)
855 continue;
856 adjval = sops[i].sem_op;
857 if (adjval == 0)
858 continue;
859 eval = semundo_adjust(p, &suptr, semid,
860 sops[i].sem_num, -adjval);
861 if (eval == 0)
862 continue;
863
864 /*
865 * Oh-Oh! We ran out of either sem_undo's or undo's.
866 * Rollback the adjustments to this point and then
867 * rollback the semaphore ups and down so we can return
868 * with an error with all structures restored. We
869 * rollback the undo's in the exact reverse order that
870 * we applied them. This guarantees that we won't run
871 * out of space as we roll things back out.
872 */
873 for (j = i - 1; j >= 0; j--) {
874 if ((sops[j].sem_flg & SEM_UNDO) == 0)
875 continue;
876 adjval = sops[j].sem_op;
877 if (adjval == 0)
878 continue;
879 if (semundo_adjust(p, &suptr, semid,
880 sops[j].sem_num, adjval) != 0)
881 panic("semop - can't undo undos");
882 }
883
884 for (j = 0; j < nsops; j++)
885 semaptr->sem_base[sops[j].sem_num].semval -=
886 sops[j].sem_op;
887
888 #ifdef SEM_DEBUG
889 printf("eval = %d from semundo_adjust\n", eval);
890 #endif
891 return(eval);
892 } /* loop through the sops */
893 } /* if (do_undos) */
894
895 /* We're definitely done - set the sempid's */
896 for (i = 0; i < nsops; i++) {
897 sopptr = &sops[i];
898 semptr = &semaptr->sem_base[sopptr->sem_num];
899 semptr->sempid = p->p_pid;
900 }
901
902 /* Do a wakeup if any semaphore was up'd. */
903 if (do_wakeup) {
904 #ifdef SEM_DEBUG
905 printf("semop: doing wakeup\n");
906 #endif
907 wakeup((caddr_t)semaptr);
908 #ifdef SEM_DEBUG
909 printf("semop: back from wakeup\n");
910 #endif
911 }
912 #ifdef SEM_DEBUG
913 printf("semop: done\n");
914 #endif
915 uap->sysmsg_result = 0;
916 return(0);
917 }
918
919 /*
920 * Go through the undo structures for this process and apply the adjustments to
921 * semaphores.
922 */
923 void
924 semexit(p)
925 struct proc *p;
926 {
927 struct sem_undo *suptr;
928 struct sem_undo **supptr;
929 int did_something;
930
931 did_something = 0;
932
933 /*
934 * Go through the chain of undo vectors looking for one
935 * associated with this process.
936 */
937
938 for (supptr = &semu_list; (suptr = *supptr) != NULL;
939 supptr = &suptr->un_next) {
940 if (suptr->un_proc == p)
941 break;
942 }
943
944 if (suptr == NULL)
945 return;
946
947 #ifdef SEM_DEBUG
948 printf("proc @%08x has undo structure with %d entries\n", p,
949 suptr->un_cnt);
950 #endif
951
952 /*
953 * If there are any active undo elements then process them.
954 */
955 if (suptr->un_cnt > 0) {
956 int ix;
957
958 for (ix = 0; ix < suptr->un_cnt; ix++) {
959 int semid = suptr->un_ent[ix].un_id;
960 int semnum = suptr->un_ent[ix].un_num;
961 int adjval = suptr->un_ent[ix].un_adjval;
962 struct semid_ds *semaptr;
963
964 semaptr = &sema[semid];
965 if ((semaptr->sem_perm.mode & SEM_ALLOC) == 0)
966 panic("semexit - semid not allocated");
967 if (semnum >= semaptr->sem_nsems)
968 panic("semexit - semnum out of range");
969
970 #ifdef SEM_DEBUG
971 printf("semexit: %08x id=%d num=%d(adj=%d) ; sem=%d\n",
972 suptr->un_proc, suptr->un_ent[ix].un_id,
973 suptr->un_ent[ix].un_num,
974 suptr->un_ent[ix].un_adjval,
975 semaptr->sem_base[semnum].semval);
976 #endif
977
978 if (adjval < 0) {
979 if (semaptr->sem_base[semnum].semval < -adjval)
980 semaptr->sem_base[semnum].semval = 0;
981 else
982 semaptr->sem_base[semnum].semval +=
983 adjval;
984 } else
985 semaptr->sem_base[semnum].semval += adjval;
986
987 wakeup((caddr_t)semaptr);
988 #ifdef SEM_DEBUG
989 printf("semexit: back from wakeup\n");
990 #endif
991 }
992 }
993
994 /*
995 * Deallocate the undo vector.
996 */
997 #ifdef SEM_DEBUG
998 printf("removing vector\n");
999 #endif
1000 suptr->un_proc = NULL;
1001 *supptr = suptr->un_next;
1002 }
DragonFly BSD