1 /* $FreeBSD: src/sys/kern/sysv_sem.c,v 1.69 2004/03/17 09:37:13 cperciva Exp $ */
4 * Implementation of SVID semaphores
6 * Author: Daniel Boulet
8 * This software is provided ``AS IS'' without any warranties of any kind.
11 #include "opt_sysvipc.h"
13 #include <sys/param.h>
14 #include <sys/systm.h>
15 #include <sys/sysproto.h>
16 #include <sys/kernel.h>
19 #include <sys/sysent.h>
20 #include <sys/sysctl.h>
21 #include <sys/malloc.h>
23 #include <sys/thread.h>
25 #include <sys/thread2.h>
27 static MALLOC_DEFINE(M_SEM, "sem", "SVID compatible semaphores");
29 static void seminit (void *);
31 static struct sem_undo *semu_alloc (struct proc *p);
32 static int semundo_adjust (struct proc *p, struct sem_undo **supptr,
33 int semid, int semnum, int adjval);
34 static void semundo_clear (int semid, int semnum);
36 /* XXX casting to (sy_call_t *) is bogus, as usual. */
37 static sy_call_t *semcalls[] = {
38 (sy_call_t *)sys___semctl, (sy_call_t *)sys_semget,
39 (sy_call_t *)sys_semop
42 static int semtot = 0;
43 static struct semid_ds *sema; /* semaphore id pool */
44 static struct sem *sem; /* semaphore pool */
45 static struct sem_undo *semu_list; /* list of active undo structures */
46 static int *semu; /* undo structure pool */
49 u_short semval; /* semaphore value */
50 pid_t sempid; /* pid of last operation */
51 u_short semncnt; /* # awaiting semval > cval */
52 u_short semzcnt; /* # awaiting semval = 0 */
56 * Undo structure (one per process)
59 struct sem_undo *un_next; /* ptr to next active undo structure */
60 struct proc *un_proc; /* owner of this structure */
61 short un_cnt; /* # of active entries */
63 short un_adjval; /* adjust on exit values */
64 short un_num; /* semaphore # */
65 int un_id; /* semid */
66 } un_ent[1]; /* undo entries */
70 * Configuration parameters
73 #define SEMMNI 22 /* # of semaphore identifiers */
76 #define SEMMNS 341 /* # of semaphores in system */
79 #define SEMUME 10 /* max # of undo entries per process */
82 #define SEMMNU 30 /* # of undo structures in system */
85 /* shouldn't need tuning */
87 #define SEMMAP 30 /* # of entries in semaphore map */
90 #define SEMMSL SEMMNS /* max # of semaphores per id */
93 #define SEMOPM 100 /* max # of operations per semop call */
96 #define SEMVMX 32767 /* semaphore maximum value */
97 #define SEMAEM 16384 /* adjust on exit max value */
100 * Due to the way semaphore memory is allocated, we have to ensure that
101 * SEMUSZ is properly aligned.
104 #define SEM_ALIGN(bytes) (((bytes) + (sizeof(long) - 1)) & ~(sizeof(long) - 1))
106 /* actual size of an undo structure */
107 #define SEMUSZ SEM_ALIGN(offsetof(struct sem_undo, un_ent[SEMUME]))
110 * Macro to find a particular sem_undo vector
112 #define SEMU(ix) ((struct sem_undo *)(((intptr_t)semu)+ix * seminfo.semusz))
115 * semaphore info struct
117 struct seminfo seminfo = {
118 SEMMAP, /* # of entries in semaphore map */
119 SEMMNI, /* # of semaphore identifiers */
120 SEMMNS, /* # of semaphores in system */
121 SEMMNU, /* # of undo structures in system */
122 SEMMSL, /* max # of semaphores per id */
123 SEMOPM, /* max # of operations per semop call */
124 SEMUME, /* max # of undo entries per process */
125 SEMUSZ, /* size in bytes of undo structure */
126 SEMVMX, /* semaphore maximum value */
127 SEMAEM /* adjust on exit max value */
130 TUNABLE_INT("kern.ipc.semmap", &seminfo.semmap);
131 TUNABLE_INT("kern.ipc.semmni", &seminfo.semmni);
132 TUNABLE_INT("kern.ipc.semmns", &seminfo.semmns);
133 TUNABLE_INT("kern.ipc.semmnu", &seminfo.semmnu);
134 TUNABLE_INT("kern.ipc.semmsl", &seminfo.semmsl);
135 TUNABLE_INT("kern.ipc.semopm", &seminfo.semopm);
136 TUNABLE_INT("kern.ipc.semume", &seminfo.semume);
137 TUNABLE_INT("kern.ipc.semusz", &seminfo.semusz);
138 TUNABLE_INT("kern.ipc.semvmx", &seminfo.semvmx);
139 TUNABLE_INT("kern.ipc.semaem", &seminfo.semaem);
141 SYSCTL_INT(_kern_ipc, OID_AUTO, semmap, CTLFLAG_RW, &seminfo.semmap, 0,
142 "Number of entries in semaphore map");
143 SYSCTL_INT(_kern_ipc, OID_AUTO, semmni, CTLFLAG_RD, &seminfo.semmni, 0,
144 "Number of semaphore identifiers");
145 SYSCTL_INT(_kern_ipc, OID_AUTO, semmns, CTLFLAG_RD, &seminfo.semmns, 0,
146 "Total number of semaphores");
147 SYSCTL_INT(_kern_ipc, OID_AUTO, semmnu, CTLFLAG_RD, &seminfo.semmnu, 0,
148 "Total number of undo structures");
149 SYSCTL_INT(_kern_ipc, OID_AUTO, semmsl, CTLFLAG_RW, &seminfo.semmsl, 0,
150 "Max number of semaphores per id");
151 SYSCTL_INT(_kern_ipc, OID_AUTO, semopm, CTLFLAG_RD, &seminfo.semopm, 0,
152 "Max number of operations per semop call");
153 SYSCTL_INT(_kern_ipc, OID_AUTO, semume, CTLFLAG_RD, &seminfo.semume, 0,
154 "Max number of undo entries per process");
155 SYSCTL_INT(_kern_ipc, OID_AUTO, semusz, CTLFLAG_RD, &seminfo.semusz, 0,
156 "Size in bytes of undo structure");
157 SYSCTL_INT(_kern_ipc, OID_AUTO, semvmx, CTLFLAG_RW, &seminfo.semvmx, 0,
158 "Semaphore maximum value");
159 SYSCTL_INT(_kern_ipc, OID_AUTO, semaem, CTLFLAG_RW, &seminfo.semaem, 0,
160 "Adjust on exit max value");
163 RO seminfo.semmap /* SEMMAP unused */
166 RO seminfo.semmnu /* undo entries per system */
168 RO seminfo.semopm /* SEMOPM unused */
170 RO seminfo.semusz /* param - derived from SEMUME for per-proc sizeof */
171 RO seminfo.semvmx /* SEMVMX unused - user param */
172 RO seminfo.semaem /* SEMAEM unused - user param */
180 sem = kmalloc(sizeof(struct sem) * seminfo.semmns, M_SEM, M_WAITOK);
181 sema = kmalloc(sizeof(struct semid_ds) * seminfo.semmni, M_SEM, M_WAITOK);
182 semu = kmalloc(seminfo.semmnu * seminfo.semusz, M_SEM, M_WAITOK);
184 for (i = 0; i < seminfo.semmni; i++) {
185 sema[i].sem_base = 0;
186 sema[i].sem_perm.mode = 0;
188 for (i = 0; i < seminfo.semmnu; i++) {
189 struct sem_undo *suptr = SEMU(i);
190 suptr->un_proc = NULL;
194 SYSINIT(sysv_sem, SI_SUB_SYSV_SEM, SI_ORDER_FIRST, seminit, NULL)
197 * Entry point for all SEM calls
199 * semsys_args(int which, a2, a3, ...) (VARARGS)
204 sys_semsys(struct semsys_args *uap)
206 struct thread *td = curthread;
207 unsigned int which = (unsigned int)uap->which;
210 if (!jail_sysvipc_allowed && td->td_ucred->cr_prison != NULL)
213 if (which >= NELEM(semcalls))
215 bcopy(&uap->a2, &uap->which,
216 sizeof(struct semsys_args) - offsetof(struct semsys_args, a2));
217 error = (*semcalls[which])(uap);
222 * Allocate a new sem_undo structure for a process
223 * (returns ptr to structure or NULL if no more room)
226 static struct sem_undo *
227 semu_alloc(struct proc *p)
230 struct sem_undo *suptr;
231 struct sem_undo **supptr;
235 * Try twice to allocate something.
236 * (we'll purge any empty structures after the first pass so
237 * two passes are always enough)
240 for (attempt = 0; attempt < 2; attempt++) {
242 * Look for a free structure.
243 * Fill it in and return it if we find one.
246 for (i = 0; i < seminfo.semmnu; i++) {
248 if (suptr->un_proc == NULL) {
249 suptr->un_next = semu_list;
258 * We didn't find a free one, if this is the first attempt
259 * then try to free some structures.
263 /* All the structures are in use - try to free some */
264 int did_something = 0;
267 while ((suptr = *supptr) != NULL) {
268 if (suptr->un_cnt == 0) {
269 suptr->un_proc = NULL;
270 *supptr = suptr->un_next;
273 supptr = &(suptr->un_next);
276 /* If we didn't free anything then just give-up */
281 * The second pass failed even though we freed
282 * something after the first pass!
283 * This is IMPOSSIBLE!
285 panic("semu_alloc - second attempt failed");
292 * Adjust a particular entry for a particular proc
296 semundo_adjust(struct proc *p, struct sem_undo **supptr, int semid, int semnum,
299 struct sem_undo *suptr;
303 /* Look for and remember the sem_undo if the caller doesn't provide
308 for (suptr = semu_list; suptr != NULL;
309 suptr = suptr->un_next) {
310 if (suptr->un_proc == p) {
318 suptr = semu_alloc(p);
326 * Look for the requested entry and adjust it (delete if adjval becomes
329 sunptr = &suptr->un_ent[0];
330 for (i = 0; i < suptr->un_cnt; i++, sunptr++) {
331 if (sunptr->un_id != semid || sunptr->un_num != semnum)
334 sunptr->un_adjval = 0;
336 sunptr->un_adjval += adjval;
337 if (sunptr->un_adjval == 0) {
339 if (i < suptr->un_cnt)
341 suptr->un_ent[suptr->un_cnt];
346 /* Didn't find the right entry - create it */
349 if (suptr->un_cnt != seminfo.semume) {
350 sunptr = &suptr->un_ent[suptr->un_cnt];
352 sunptr->un_adjval = adjval;
353 sunptr->un_id = semid; sunptr->un_num = semnum;
360 semundo_clear(int semid, int semnum)
362 struct sem_undo *suptr;
364 for (suptr = semu_list; suptr != NULL; suptr = suptr->un_next) {
365 struct undo *sunptr = &suptr->un_ent[0];
368 while (i < suptr->un_cnt) {
369 if (sunptr->un_id == semid) {
370 if (semnum == -1 || sunptr->un_num == semnum) {
372 if (i < suptr->un_cnt) {
374 suptr->un_ent[suptr->un_cnt];
387 * Note that the user-mode half of this passes a union, not a pointer
392 sys___semctl(struct __semctl_args *uap)
394 struct thread *td = curthread;
395 int semid = uap->semid;
396 int semnum = uap->semnum;
398 union semun *arg = uap->arg;
399 union semun real_arg;
400 struct ucred *cred = td->td_ucred;
402 struct semid_ds sbuf;
403 struct semid_ds *semaptr;
404 struct semid_ds *semakptr;
407 kprintf("call to semctl(%d, %d, %d, 0x%x)\n", semid, semnum, cmd, arg);
410 if (!jail_sysvipc_allowed && cred->cr_prison != NULL)
416 * For this command we assume semid is an array index
417 * rather than an IPC id.
419 if (semid < 0 || semid >= seminfo.semmni) {
423 semakptr = &sema[semid];
424 lwkt_getpooltoken(semakptr);
425 if ((semakptr->sem_perm.mode & SEM_ALLOC) == 0) {
427 lwkt_relpooltoken(semakptr);
430 if ((eval = ipcperm(td->td_proc, &semakptr->sem_perm, IPC_R))) {
431 lwkt_relpooltoken(semakptr);
434 bcopy(&semakptr, arg->buf, sizeof(struct semid_ds));
435 rval = IXSEQ_TO_IPCID(semid, semakptr->sem_perm);
436 lwkt_relpooltoken(semakptr);
440 semid = IPCID_TO_IX(semid);
441 if (semid < 0 || semid >= seminfo.semmni) {
444 semaptr = &sema[semid];
445 lwkt_getpooltoken(semaptr);
447 if ((semaptr->sem_perm.mode & SEM_ALLOC) == 0 ||
448 semaptr->sem_perm.seq != IPCID_TO_SEQ(uap->semid)) {
449 lwkt_relpooltoken(semaptr);
458 if ((eval = ipcperm(td->td_proc, &semaptr->sem_perm, IPC_M)) != 0)
460 semaptr->sem_perm.cuid = cred->cr_uid;
461 semaptr->sem_perm.uid = cred->cr_uid;
462 semtot -= semaptr->sem_nsems;
463 for (i = semaptr->sem_base - sem; i < semtot; i++)
464 sem[i] = sem[i + semaptr->sem_nsems];
465 for (i = 0; i < seminfo.semmni; i++) {
466 if ((sema[i].sem_perm.mode & SEM_ALLOC) &&
467 sema[i].sem_base > semaptr->sem_base)
468 sema[i].sem_base -= semaptr->sem_nsems;
470 semaptr->sem_perm.mode = 0;
471 semundo_clear(semid, -1);
472 wakeup((caddr_t)semaptr);
476 eval = ipcperm(td->td_proc, &semaptr->sem_perm, IPC_M);
479 if ((eval = copyin(arg, &real_arg, sizeof(real_arg))) != 0)
481 if ((eval = copyin(real_arg.buf, (caddr_t)&sbuf,
482 sizeof(sbuf))) != 0) {
485 semaptr->sem_perm.uid = sbuf.sem_perm.uid;
486 semaptr->sem_perm.gid = sbuf.sem_perm.gid;
487 semaptr->sem_perm.mode = (semaptr->sem_perm.mode & ~0777) |
488 (sbuf.sem_perm.mode & 0777);
489 semaptr->sem_ctime = time_second;
493 if ((eval = ipcperm(td->td_proc, &semaptr->sem_perm, IPC_R)))
495 if ((eval = copyin(arg, &real_arg, sizeof(real_arg))) != 0)
497 eval = copyout(semaptr, real_arg.buf, sizeof(struct semid_ds));
501 eval = ipcperm(td->td_proc, &semaptr->sem_perm, IPC_R);
504 if (semnum < 0 || semnum >= semaptr->sem_nsems) {
508 rval = semaptr->sem_base[semnum].semncnt;
512 eval = ipcperm(td->td_proc, &semaptr->sem_perm, IPC_R);
515 if (semnum < 0 || semnum >= semaptr->sem_nsems) {
519 rval = semaptr->sem_base[semnum].sempid;
523 eval = ipcperm(td->td_proc, &semaptr->sem_perm, IPC_R);
526 if (semnum < 0 || semnum >= semaptr->sem_nsems) {
530 rval = semaptr->sem_base[semnum].semval;
534 eval = ipcperm(td->td_proc, &semaptr->sem_perm, IPC_R);
537 if ((eval = copyin(arg, &real_arg, sizeof(real_arg))) != 0)
539 for (i = 0; i < semaptr->sem_nsems; i++) {
540 eval = copyout(&semaptr->sem_base[i].semval,
542 sizeof(real_arg.array[0]));
549 eval = ipcperm(td->td_proc, &semaptr->sem_perm, IPC_R);
552 if (semnum < 0 || semnum >= semaptr->sem_nsems) {
556 rval = semaptr->sem_base[semnum].semzcnt;
560 eval = ipcperm(td->td_proc, &semaptr->sem_perm, IPC_W);
563 if (semnum < 0 || semnum >= semaptr->sem_nsems) {
567 if ((eval = copyin(arg, &real_arg, sizeof(real_arg))) != 0)
569 semaptr->sem_base[semnum].semval = real_arg.val;
570 semundo_clear(semid, semnum);
571 wakeup((caddr_t)semaptr);
575 eval = ipcperm(td->td_proc, &semaptr->sem_perm, IPC_W);
578 if ((eval = copyin(arg, &real_arg, sizeof(real_arg))) != 0)
580 for (i = 0; i < semaptr->sem_nsems; i++) {
581 eval = copyin(&real_arg.array[i],
582 (caddr_t)&semaptr->sem_base[i].semval,
583 sizeof(real_arg.array[0]));
587 semundo_clear(semid, -1);
588 wakeup((caddr_t)semaptr);
595 lwkt_relpooltoken(semaptr);
598 uap->sysmsg_result = rval;
606 sys_semget(struct semget_args *uap)
608 struct thread *td = curthread;
611 int nsems = uap->nsems;
612 int semflg = uap->semflg;
613 struct ucred *cred = td->td_ucred;
616 kprintf("semget(0x%x, %d, 0%o)\n", key, nsems, semflg);
619 if (!jail_sysvipc_allowed && cred->cr_prison != NULL)
624 if (key != IPC_PRIVATE) {
625 for (semid = 0; semid < seminfo.semmni; semid++) {
626 if ((sema[semid].sem_perm.mode & SEM_ALLOC) == 0 ||
627 sema[semid].sem_perm.key != key) {
630 lwkt_getpooltoken(&sema[semid]);
631 if ((sema[semid].sem_perm.mode & SEM_ALLOC) == 0 ||
632 sema[semid].sem_perm.key != key) {
633 lwkt_relpooltoken(&sema[semid]);
638 if (semid < seminfo.semmni) {
640 kprintf("found public key\n");
642 if ((eval = ipcperm(td->td_proc,
643 &sema[semid].sem_perm,
645 lwkt_relpooltoken(&sema[semid]);
648 if (nsems > 0 && sema[semid].sem_nsems < nsems) {
650 kprintf("too small\n");
653 lwkt_relpooltoken(&sema[semid]);
656 if ((semflg & IPC_CREAT) && (semflg & IPC_EXCL)) {
658 kprintf("not exclusive\n");
661 lwkt_relpooltoken(&sema[semid]);
669 kprintf("need to allocate the semid_ds\n");
671 if (key == IPC_PRIVATE || (semflg & IPC_CREAT)) {
672 if (nsems <= 0 || nsems > seminfo.semmsl) {
674 kprintf("nsems out of range (0<%d<=%d)\n",
675 nsems, seminfo.semmsl);
680 if (nsems > seminfo.semmns - semtot) {
682 kprintf("not enough semaphores left "
683 "(need %d, got %d)\n",
684 nsems, seminfo.semmns - semtot);
689 for (semid = 0; semid < seminfo.semmni; semid++) {
690 if (sema[semid].sem_perm.mode & SEM_ALLOC)
692 lwkt_getpooltoken(&sema[semid]);
693 if (sema[semid].sem_perm.mode & SEM_ALLOC) {
694 lwkt_relpooltoken(&sema[semid]);
699 if (semid == seminfo.semmni) {
701 kprintf("no more semid_ds's available\n");
707 kprintf("semid %d is available\n", semid);
709 sema[semid].sem_perm.key = key;
710 sema[semid].sem_perm.cuid = cred->cr_uid;
711 sema[semid].sem_perm.uid = cred->cr_uid;
712 sema[semid].sem_perm.cgid = cred->cr_gid;
713 sema[semid].sem_perm.gid = cred->cr_gid;
714 sema[semid].sem_perm.mode = (semflg & 0777) | SEM_ALLOC;
715 sema[semid].sem_perm.seq =
716 (sema[semid].sem_perm.seq + 1) & 0x7fff;
717 sema[semid].sem_nsems = nsems;
718 sema[semid].sem_otime = 0;
719 sema[semid].sem_ctime = time_second;
720 sema[semid].sem_base = &sem[semtot];
722 bzero(sema[semid].sem_base,
723 sizeof(sema[semid].sem_base[0])*nsems);
725 kprintf("sembase = 0x%x, next = 0x%x\n",
726 sema[semid].sem_base, &sem[semtot]);
731 kprintf("didn't find it and wasn't asked to create it\n");
739 IXSEQ_TO_IPCID(semid, sema[semid].sem_perm);
740 lwkt_relpooltoken(&sema[semid]);
749 sys_semop(struct semop_args *uap)
751 struct thread *td = curthread;
752 int semid = uap->semid;
753 u_int nsops = uap->nsops;
754 struct sembuf sops[MAX_SOPS];
755 struct semid_ds *semaptr;
756 struct sembuf *sopptr;
758 struct sem_undo *suptr = NULL;
760 int do_wakeup, do_undos;
763 kprintf("call to semop(%d, 0x%x, %u)\n", semid, sops, nsops);
766 if (!jail_sysvipc_allowed && td->td_ucred->cr_prison != NULL)
769 semid = IPCID_TO_IX(semid); /* Convert back to zero origin */
771 if (semid < 0 || semid >= seminfo.semmni) {
775 semaptr = &sema[semid];
776 lwkt_getpooltoken(semaptr);
777 if ((semaptr->sem_perm.mode & SEM_ALLOC) == 0) {
781 if (semaptr->sem_perm.seq != IPCID_TO_SEQ(uap->semid)) {
786 if ((eval = ipcperm(td->td_proc, &semaptr->sem_perm, IPC_W))) {
788 kprintf("eval = %d from ipaccess\n", eval);
793 if (nsops > MAX_SOPS) {
795 kprintf("too many sops (max=%d, nsops=%u)\n", MAX_SOPS, nsops);
801 if ((eval = copyin(uap->sops, &sops, nsops * sizeof(sops[0]))) != 0) {
803 kprintf("eval = %d from copyin(%08x, %08x, %u)\n", eval,
804 uap->sops, &sops, nsops * sizeof(sops[0]));
810 * Loop trying to satisfy the vector of requests.
811 * If we reach a point where we must wait, any requests already
812 * performed are rolled back and we go to sleep until some other
813 * process wakes us up. At this point, we start all over again.
815 * This ensures that from the perspective of other tasks, a set
816 * of requests is atomic (never partially satisfied).
823 for (i = 0; i < nsops; i++) {
826 if (sopptr->sem_num >= semaptr->sem_nsems) {
831 semptr = &semaptr->sem_base[sopptr->sem_num];
834 kprintf("semop: semaptr=%x, sem_base=%x, semptr=%x, sem[%d]=%d : op=%d, flag=%s\n",
835 semaptr, semaptr->sem_base, semptr,
836 sopptr->sem_num, semptr->semval, sopptr->sem_op,
837 (sopptr->sem_flg & IPC_NOWAIT) ? "nowait" : "wait");
840 if (sopptr->sem_op < 0) {
841 if (semptr->semval + sopptr->sem_op < 0) {
843 kprintf("semop: can't do it now\n");
847 semptr->semval += sopptr->sem_op;
848 if (semptr->semval == 0 &&
852 if (sopptr->sem_flg & SEM_UNDO)
854 } else if (sopptr->sem_op == 0) {
855 if (semptr->semval > 0) {
857 kprintf("semop: not zero now\n");
862 if (semptr->semncnt > 0)
864 semptr->semval += sopptr->sem_op;
865 if (sopptr->sem_flg & SEM_UNDO)
871 * Did we get through the entire vector?
877 * No ... rollback anything that we've already done
880 kprintf("semop: rollback 0 through %d\n", i-1);
882 for (j = 0; j < i; j++)
883 semaptr->sem_base[sops[j].sem_num].semval -=
887 * If the request that we couldn't satisfy has the
888 * NOWAIT flag set then return with EAGAIN.
890 if (sopptr->sem_flg & IPC_NOWAIT) {
895 if (sopptr->sem_op == 0)
901 kprintf("semop: good night!\n");
903 eval = tsleep((caddr_t)semaptr, PCATCH, "semwait", 0);
905 kprintf("semop: good morning (eval=%d)!\n", eval);
908 suptr = NULL; /* sem_undo may have been reallocated */
910 /* return code is checked below, after sem[nz]cnt-- */
913 * Make sure that the semaphore still exists
915 if ((semaptr->sem_perm.mode & SEM_ALLOC) == 0 ||
916 semaptr->sem_perm.seq != IPCID_TO_SEQ(uap->semid)) {
922 * The semaphore is still alive. Readjust the count of
925 if (sopptr->sem_op == 0)
931 * Is it really morning, or was our sleep interrupted?
932 * (Delayed check of tsleep() return code because we
933 * need to decrement sem[nz]cnt either way.)
940 kprintf("semop: good morning!\n");
946 * Process any SEM_UNDO requests.
949 for (i = 0; i < nsops; i++) {
951 * We only need to deal with SEM_UNDO's for non-zero
956 if ((sops[i].sem_flg & SEM_UNDO) == 0)
958 adjval = sops[i].sem_op;
961 eval = semundo_adjust(td->td_proc, &suptr, semid,
962 sops[i].sem_num, -adjval);
967 * Oh-Oh! We ran out of either sem_undo's or undo's.
968 * Rollback the adjustments to this point and then
969 * rollback the semaphore ups and down so we can return
970 * with an error with all structures restored. We
971 * rollback the undo's in the exact reverse order that
972 * we applied them. This guarantees that we won't run
973 * out of space as we roll things back out.
975 for (j = i - 1; j >= 0; j--) {
976 if ((sops[j].sem_flg & SEM_UNDO) == 0)
978 adjval = sops[j].sem_op;
981 if (semundo_adjust(td->td_proc, &suptr, semid,
982 sops[j].sem_num, adjval) != 0)
983 panic("semop - can't undo undos");
986 for (j = 0; j < nsops; j++)
987 semaptr->sem_base[sops[j].sem_num].semval -=
991 kprintf("eval = %d from semundo_adjust\n", eval);
994 } /* loop through the sops */
995 } /* if (do_undos) */
997 /* We're definitely done - set the sempid's */
998 for (i = 0; i < nsops; i++) {
1000 semptr = &semaptr->sem_base[sopptr->sem_num];
1001 semptr->sempid = td->td_proc->p_pid;
1004 /* Do a wakeup if any semaphore was up'd. */
1007 kprintf("semop: doing wakeup\n");
1009 wakeup((caddr_t)semaptr);
1011 kprintf("semop: back from wakeup\n");
1015 kprintf("semop: done\n");
1017 uap->sysmsg_result = 0;
1020 lwkt_relpooltoken(semaptr);
1026 * Go through the undo structures for this process and apply the adjustments to
1030 semexit(struct proc *p)
1032 struct sem_undo *suptr;
1033 struct sem_undo **supptr;
1039 * Go through the chain of undo vectors looking for one
1040 * associated with this process.
1043 for (supptr = &semu_list; (suptr = *supptr) != NULL;
1044 supptr = &suptr->un_next) {
1045 if (suptr->un_proc == p)
1053 kprintf("proc @%08x has undo structure with %d entries\n", p,
1058 * If there are any active undo elements then process them.
1060 if (suptr->un_cnt > 0) {
1063 for (ix = 0; ix < suptr->un_cnt; ix++) {
1064 int semid = suptr->un_ent[ix].un_id;
1065 int semnum = suptr->un_ent[ix].un_num;
1066 int adjval = suptr->un_ent[ix].un_adjval;
1067 struct semid_ds *semaptr;
1069 semaptr = &sema[semid];
1070 if ((semaptr->sem_perm.mode & SEM_ALLOC) == 0)
1071 panic("semexit - semid not allocated");
1072 if (semnum >= semaptr->sem_nsems)
1073 panic("semexit - semnum out of range");
1076 kprintf("semexit: %08x id=%d num=%d(adj=%d) ; sem=%d\n",
1077 suptr->un_proc, suptr->un_ent[ix].un_id,
1078 suptr->un_ent[ix].un_num,
1079 suptr->un_ent[ix].un_adjval,
1080 semaptr->sem_base[semnum].semval);
1084 if (semaptr->sem_base[semnum].semval < -adjval)
1085 semaptr->sem_base[semnum].semval = 0;
1087 semaptr->sem_base[semnum].semval +=
1090 semaptr->sem_base[semnum].semval += adjval;
1092 wakeup((caddr_t)semaptr);
1094 kprintf("semexit: back from wakeup\n");
1100 * Deallocate the undo vector.
1103 kprintf("removing vector\n");
1105 suptr->un_proc = NULL;
1106 *supptr = suptr->un_next;