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-rw-r--r--sys/kern/sysv_sem.c1114
1 files changed, 1114 insertions, 0 deletions
diff --git a/sys/kern/sysv_sem.c b/sys/kern/sysv_sem.c
new file mode 100644
index 000000000000..6344018d9514
--- /dev/null
+++ b/sys/kern/sysv_sem.c
@@ -0,0 +1,1114 @@
+/*
+ * Implementation of SVID semaphores
+ *
+ * Author: Daniel Boulet
+ *
+ * This software is provided ``AS IS'' without any warranties of any kind.
+ */
+
+#ifdef SYSVSEM
+
+#include "param.h"
+#include "systm.h"
+#include "kernel.h"
+#include "proc.h"
+#include "sem.h"
+#include "malloc.h"
+
+static int semctl(), semget(), semop(), semconfig();
+int (*semcalls[])() = { semctl, semget, semop, semconfig };
+int semtot = 0;
+
+static struct proc *semlock_holder = NULL;
+
+void
+seminit()
+{
+ register int i;
+ vm_offset_t whocares1, whocares2;
+
+ if ( sema == NULL ) {
+ panic("sema is NULL");
+ }
+ for ( i = 0; i < seminfo.semmni; i += 1 ) {
+ sema[i].sem_base = 0;
+ sema[i].sem_perm.mode = 0;
+ }
+ if ( semu == NULL ) {
+ panic("semu is NULL");
+ }
+ for ( i = 0; i < seminfo.semmnu; i += 1 ) {
+ register struct sem_undo *suptr = SEMU(i);
+ suptr->un_proc = NULL;
+ }
+ semu_list = NULL;
+}
+
+TEXT_SET(pseudo_set, seminit);
+
+/*
+ * Entry point for all SEM calls
+ */
+
+struct semsys_args {
+ u_int which;
+};
+
+int
+semsys(p, uap, retval)
+ struct proc *p;
+ struct semsys_args *uap;
+ int *retval;
+{
+ while ( semlock_holder != NULL && semlock_holder != p ) {
+ /* printf("semaphore facility locked - sleeping ...\n"); */
+ sleep( (caddr_t)&semlock_holder, (PZERO - 4) );
+ }
+
+ if (uap->which >= sizeof(semcalls)/sizeof(semcalls[0]))
+ return (EINVAL);
+ return ((*semcalls[uap->which])(p, &uap[1], retval));
+}
+
+/*
+ * Lock or unlock the entire semaphore facility.
+ *
+ * This will probably eventually evolve into a general purpose semaphore
+ * facility status enquiry mechanism (I don't like the "read /dev/kmem"
+ * approach currently taken by ipcs and the amount of info that we want
+ * to be able to extract for ipcs is probably beyond what the capability
+ * of the getkerninfo facility.
+ *
+ * At the time that the current version of semconfig was written, ipcs is
+ * the only user of the semconfig facility. It uses it to ensure that the
+ * semaphore facility data structures remain static while it fishes around
+ * in /dev/kmem.
+ */
+
+struct semconfig_args {
+ semconfig_ctl_t flag;
+};
+
+int
+semconfig(p, uap, retval)
+ struct proc *p;
+ struct semconfig_args *uap;
+ int *retval;
+{
+ int eval = 0;
+
+ switch ( uap->flag ) {
+ case SEM_CONFIG_FREEZE:
+ semlock_holder = p;
+ break;
+ case SEM_CONFIG_THAW:
+ semlock_holder = NULL;
+ wakeup( (caddr_t)&semlock_holder );
+ break;
+ default:
+ printf("semconfig: unknown flag parameter value (%d) - ignored\n",uap->flag);
+ eval = EINVAL;
+ break;
+ }
+
+ *retval = 0;
+ return(eval);
+}
+
+/*
+ * Allocate a new sem_undo structure for a process
+ * (returns ptr to structure or NULL if no more room)
+ */
+
+struct sem_undo *
+semu_alloc(struct proc *p)
+{
+ register int i;
+ register struct sem_undo *suptr;
+ register struct sem_undo **supptr;
+ int attempt;
+
+ /*
+ * Try twice to allocate something.
+ * (we'll purge any empty structures after the first pass so
+ * two passes are always enough)
+ */
+
+ for ( attempt = 0; attempt < 2; attempt += 1 ) {
+
+ /*
+ * Look for a free structure.
+ * Fill it in and return it if we find one.
+ */
+
+ for ( i = 0; i < seminfo.semmnu; i += 1 ) {
+ suptr = SEMU(i);
+ if ( suptr->un_proc == NULL ) {
+ suptr->un_next = semu_list;
+ semu_list = suptr;
+ suptr->un_cnt = 0;
+ suptr->un_proc = p;
+ return(suptr);
+ }
+ }
+
+ /*
+ * We didn't find a free one, if this is the first attempt
+ * then try to free some structures.
+ */
+
+ if ( attempt == 0 ) {
+
+ /* All the structures are in use - try to free some */
+
+ int did_something = 0;
+
+ supptr = &semu_list;
+ while ( (suptr = *supptr) != NULL ) {
+ if ( suptr->un_cnt == 0 ) {
+ suptr->un_proc = NULL;
+ *supptr = suptr->un_next;
+ did_something = 1;
+ } else {
+ supptr = &(suptr->un_next);
+ }
+ }
+
+ /* If we didn't free anything then just give-up */
+
+ if ( !did_something ) {
+ return(NULL);
+ }
+
+ } else {
+
+ /*
+ * The second pass failed even though we freed
+ * something after the first pass!
+ * This is IMPOSSIBLE!
+ */
+
+ panic("semu_alloc - second attempt failed");
+
+ }
+
+ }
+
+ /* NOTREACHED */
+ while (1);
+}
+
+/*
+ * Adjust a particular entry for a particular proc
+ */
+
+int
+semundo_adjust(register struct proc *p,struct sem_undo **supptr,int semid,int semnum,int adjval)
+{
+ register struct sem_undo *suptr;
+ register struct undo *sunptr;
+ int i;
+
+ /* Look for and remember the sem_undo if the caller doesn't provide it */
+
+ suptr = *supptr;
+ if ( suptr == NULL ) {
+ /* printf("adjust: need to find suptr\n"); */
+ for ( suptr = semu_list; suptr != NULL; suptr = suptr->un_next ) {
+ if ( suptr->un_proc == p ) {
+ /* printf("adjust: found suptr @%08x\n",suptr); */
+ *supptr = suptr;
+ break;
+ }
+ }
+ if ( suptr == NULL ) {
+ if ( adjval == 0 ) {
+ return(0); /* Don't create it if it doesn't exist */
+ }
+ suptr = semu_alloc(p);
+ if ( suptr == NULL ) {
+ return(ENOSPC);
+ }
+ /* printf("adjust: allocated suptr @%08x\n",suptr); */
+ *supptr = suptr;
+ }
+ }
+
+ /* Look for the requested entry and adjust it (delete if adjval becomes 0) */
+
+ sunptr = &(suptr->un_ent[0]);
+ for ( i = 0; i < suptr->un_cnt; i += 1, sunptr += 1 ) {
+
+ if ( sunptr->un_id == semid && sunptr->un_num == semnum ) {
+
+ /* Found the right entry - adjust it */
+
+ if ( adjval == 0 ) {
+ sunptr->un_adjval = 0;
+ } else {
+ /* printf("adjust: %08x %d:%d(%d) += %d\n",suptr->un_proc,semid,semnum,sunptr->un_adjval,adjval); */
+ sunptr->un_adjval += adjval;
+ }
+ if ( sunptr->un_adjval == 0 ) {
+ /* printf("adjust: %08x deleting entry %d:%d\n",suptr->un_proc,semid,semnum); */
+ suptr->un_cnt -= 1;
+ if ( i < suptr->un_cnt ) {
+ suptr->un_ent[i] = suptr->un_ent[suptr->un_cnt];
+ }
+ }
+ return(0);
+
+ }
+ }
+
+ /* Didn't find the right entry - create it */
+
+ if ( adjval == 0 ) {
+ return(0);
+ }
+ if ( suptr->un_cnt == SEMUME ) {
+ return(EINVAL);
+ } else {
+ /* printf("adjust: %08x allocating entry %d as %d:%d(%d)\n",suptr->un_proc,suptr->un_cnt,semid,semnum,adjval); */
+ sunptr = &(suptr->un_ent[suptr->un_cnt]);
+ suptr->un_cnt += 1;
+ sunptr->un_adjval = adjval;
+ sunptr->un_id = semid; sunptr->un_num = semnum;
+ }
+ return(0);
+}
+
+
+void
+semundo_clear(int semid,int semnum)
+{
+ register struct sem_undo *suptr;
+
+ for ( suptr = semu_list; suptr != NULL; suptr = suptr->un_next ) {
+
+ register struct undo *sunptr = &(suptr->un_ent[0]);
+ register int i = 0;
+
+ while ( i < suptr->un_cnt ) {
+ int advance = 1;
+
+ if ( sunptr->un_id == semid ) {
+ if ( semnum == -1 || sunptr->un_num == semnum ) {
+ /* printf("clear: %08x %d:%d(%d)\n",suptr->un_proc,semid,sunptr->un_num,sunptr->un_adjval); */
+ suptr->un_cnt -= 1;
+ if ( i < suptr->un_cnt ) {
+ suptr->un_ent[i] = suptr->un_ent[suptr->un_cnt];
+ advance = 0;
+ }
+ }
+ if ( semnum != -1 ) {
+ break;
+ }
+ }
+
+ if ( advance ) {
+ i += 1;
+ sunptr += 1;
+ }
+
+ }
+
+ }
+
+}
+
+struct semctl_args {
+ int semid;
+ int semnum;
+ int cmd;
+ union semun *arg;
+};
+
+int
+semctl(p, uap, retval)
+ struct proc *p;
+ register struct semctl_args *uap;
+ int *retval;
+{
+ int semid = uap->semid;
+ int semnum = uap->semnum;
+ int cmd = uap->cmd;
+ union semun *arg = uap->arg;
+ union semun real_arg;
+ struct ucred *cred = p->p_ucred;
+ int i, rval, eval;
+ struct semid_ds sbuf;
+ register struct semid_ds *semaptr;
+
+#ifdef SEM_DEBUG
+ printf("call to semctl(%d,%d,%d,0x%x)\n",semid,semnum,cmd,arg);
+#endif
+
+ semid = IPCID_TO_IX(semid);
+
+ if ( semid < 0 || semid >= seminfo.semmsl ) {
+ /* printf("semid out of range (0<=%d<%d)\n",semid,seminfo.semmsl); */
+ return(EINVAL);
+ }
+
+ semaptr = &sema[semid];
+
+ if ( semaptr->sem_perm.seq != IPCID_TO_SEQ(uap->semid) ) {
+ /* printf("invalid sequence number\n"); */
+ return(EINVAL);
+ }
+
+ if ( (semaptr->sem_perm.mode & SEM_ALLOC) == 0 ) {
+ /* printf("no such semaphore id\n"); */
+ return(EINVAL);
+ }
+
+ eval = 0;
+ rval = 0;
+
+ switch (cmd) {
+
+ case IPC_RMID:
+ if ( cred->cr_uid != 0
+ && semaptr->sem_perm.cuid != cred->cr_uid
+ && semaptr->sem_perm.uid != cred->cr_uid ) {
+ return(EPERM);
+ }
+ semaptr->sem_perm.cuid = cred->cr_uid;
+ semaptr->sem_perm.uid = cred->cr_uid;
+ semtot -= semaptr->sem_nsems;
+ for ( i = semaptr->sem_base - sem; i < semtot; i += 1 ) {
+ /* printf("0x%x = 0x%x; ",&sem[i],&sem[i + semaptr->sem_nsems]); */
+ sem[i] = sem[i + semaptr->sem_nsems];
+ }
+ /* printf("\n"); */
+ for ( i = 0; i < seminfo.semmni; i += 1 ) {
+ if ( (sema[i].sem_perm.mode & SEM_ALLOC)
+ && sema[i].sem_base > semaptr->sem_base ) {
+ /* printf("sema[%d].sem_base was 0x%x",i,sema[i].sem_base); */
+ sema[i].sem_base -= semaptr->sem_nsems;
+ /* printf(", now 0x%x\n",sema[i].sem_base); */
+ }
+ }
+ semaptr->sem_perm.mode = 0;
+
+ /* Delete any undo entries for this semid */
+
+ semundo_clear(semid,-1);
+
+ /* Make sure that anybody who is waiting notices the deletion */
+
+ wakeup( (caddr_t)semaptr );
+
+ break;
+
+ case IPC_SET:
+ /* printf("IPC_SET\n"); */
+ if ( cred->cr_uid != 0
+ && semaptr->sem_perm.cuid != cred->cr_uid
+ && semaptr->sem_perm.uid != cred->cr_uid ) {
+ return(EPERM);
+ }
+ if ( (eval = copyin(arg, &real_arg, sizeof(real_arg))) != 0 ) {
+ return(eval);
+ }
+ if ( (eval = copyin(real_arg.buf, (caddr_t)&sbuf, sizeof(sbuf)) ) != 0 ) {
+ return(eval);
+ }
+ semaptr->sem_perm.uid = sbuf.sem_perm.uid;
+ semaptr->sem_perm.gid = sbuf.sem_perm.gid;
+ semaptr->sem_perm.mode = (semaptr->sem_perm.mode & ~0777)
+ | (sbuf.sem_perm.mode & 0777);
+ semaptr->sem_ctime = time.tv_sec;
+ break;
+
+ case IPC_STAT:
+ /* printf("IPC_STAT\n"); */
+ if ( (eval = ipcaccess(&semaptr->sem_perm, IPC_R, cred)) ) {
+ return(eval);
+ }
+ rval = 0;
+ if ( (eval = copyin(arg, &real_arg, sizeof(real_arg))) != 0 ) {
+ return(eval);
+ }
+ eval = copyout((caddr_t)semaptr, real_arg.buf, sizeof(struct semid_ds)) ;
+ break;
+
+ case GETNCNT:
+ /* printf("GETNCNT(%d)\n",semnum); */
+ if ( (eval = ipcaccess(&semaptr->sem_perm, IPC_R, cred)) ) {
+ return(eval);
+ }
+ if ( semnum < 0 || semnum >= semaptr->sem_nsems ) return(EINVAL);
+ rval = semaptr->sem_base[semnum].semncnt;
+ break;
+
+ case GETPID:
+ /* printf("GETPID(%d)\n",semnum); */
+ if ( (eval = ipcaccess(&semaptr->sem_perm, IPC_R, cred)) ) {
+ return(eval);
+ }
+ if ( semnum < 0 || semnum >= semaptr->sem_nsems ) return(EINVAL);
+ rval = semaptr->sem_base[semnum].sempid;
+ break;
+
+ case GETVAL:
+ /* printf("GETVAL(%d)\n",semnum); */
+ if ( (eval = ipcaccess(&semaptr->sem_perm, IPC_R, cred)) ) {
+ return(eval);
+ }
+ if ( semnum < 0 || semnum >= semaptr->sem_nsems ) return(EINVAL);
+ rval = semaptr->sem_base[semnum].semval;
+ break;
+
+ case GETALL:
+ /* printf("GETALL\n"); */
+ if ( (eval = ipcaccess(&semaptr->sem_perm, IPC_R, cred)) ) {
+ return(eval);
+ }
+ rval = 0;
+ if ( (eval = copyin(arg, &real_arg, sizeof(real_arg))) != 0 ) {
+ /* printf("initial copyin failed (addr=0x%x)\n",arg); */
+ return(eval);
+ }
+ /* printf("%d semaphores\n",semaptr->sem_nsems); */
+ for ( i = 0; i < semaptr->sem_nsems; i += 1 ) {
+ /* printf("copyout to 0x%x\n",&real_arg.array[i]); */
+ eval =
+ copyout((caddr_t)&semaptr->sem_base[i].semval,
+ &real_arg.array[i],
+ sizeof(real_arg.array[0]));
+ if ( eval != 0 ) {
+ /* printf("copyout to 0x%x failed\n",&real_arg.array[i]); */
+ break;
+ }
+ }
+ break;
+
+ case GETZCNT:
+ if ( (eval = ipcaccess(&semaptr->sem_perm, IPC_R, cred)) ) {
+ return(eval);
+ }
+ /* printf("GETZCNT(%d)\n",semnum); */
+ if ( semnum < 0 || semnum >= semaptr->sem_nsems ) return(EINVAL);
+ rval = semaptr->sem_base[semnum].semzcnt;
+ break;
+
+ case SETVAL:
+#ifdef SEM_DEBUG
+ printf("SETVAL(%d)\n",semnum);
+#endif
+ if ( (eval = ipcaccess(&semaptr->sem_perm, IPC_W, cred)) ) {
+ return(eval);
+ }
+ if ( semnum < 0 || semnum >= semaptr->sem_nsems ) return(EINVAL);
+ rval = 0;
+ if ( (eval = copyin(arg, &real_arg, sizeof(real_arg))) != 0 ) {
+ return(eval);
+ }
+#ifdef SEM_DEBUG
+ printf("semaptr=%x, sem_base=%x, semptr=%x, oldval=%d, ",
+ semaptr,semaptr->sem_base,&semaptr->sem_base[semnum],semaptr->sem_base[semnum].semval);
+#endif
+ semaptr->sem_base[semnum].semval = real_arg.val;
+#ifdef SEM_DEBUG
+ printf(" newval=%d\n", semaptr->sem_base[semnum].semval);
+#endif
+ semundo_clear(semid,semnum);
+ wakeup( (caddr_t)semaptr ); /* somebody else might care */
+ break;
+
+ case SETALL:
+ /* printf("SETALL\n"); */
+ if ( (eval = ipcaccess(&semaptr->sem_perm, IPC_W, cred)) ) {
+ return(eval);
+ }
+ rval = 0;
+ if ( (eval = copyin(arg, &real_arg, sizeof(real_arg))) != 0 ) {
+ return(eval);
+ }
+ for ( i = 0; i < semaptr->sem_nsems; i += 1 ) {
+ eval =
+ copyin(&real_arg.array[i],
+ (caddr_t)&semaptr->sem_base[i].semval,
+ sizeof(real_arg.array[0]));
+ if ( eval != 0 ) {
+ break;
+ }
+ }
+ semundo_clear(semid,-1);
+ wakeup( (caddr_t)semaptr ); /* somebody else might care */
+ break;
+ default:
+ /* printf("invalid command %d\n",cmd); */
+ return(EINVAL);
+ }
+
+ if ( eval == 0 ) {
+ *retval = rval;
+ }
+ return(eval);
+}
+
+struct semget_args {
+ key_t key;
+ int nsems;
+ int semflg;
+};
+
+int
+semget(p, uap, retval)
+ struct proc *p;
+ register struct semget_args *uap;
+ int *retval;
+{
+ int semid, eval;
+ int key = uap->key;
+ int nsems = uap->nsems;
+ int semflg = uap->semflg;
+ struct ucred *cred = p->p_ucred;
+
+#ifdef SEM_DEBUG
+ printf("semget(0x%x,%d,0%o)\n",key,nsems,semflg);
+#endif
+
+ if ( key == IPC_PRIVATE ) {
+#ifdef SEM_DEBUG
+ printf("private key\n");
+#endif
+ semid = seminfo.semmni;
+ } else {
+ for ( semid = 0; semid < seminfo.semmni; semid += 1 ) {
+ if ( (sema[semid].sem_perm.mode & SEM_ALLOC)
+ && sema[semid].sem_perm.key == key ) {
+ break;
+ }
+ }
+ if ( semid < seminfo.semmni ) {
+#ifdef SEM_DEBUG
+ printf("found public key\n");
+#endif
+ if ( (eval = ipcaccess(&sema[semid].sem_perm, semflg & 0700, cred)) ) {
+ return(eval);
+ }
+ if ( nsems > 0 && sema[semid].sem_nsems < nsems ) {
+#ifdef SEM_DEBUG
+ printf("too small\n");
+#endif
+ return(EINVAL);
+ }
+ if ( (semflg & IPC_CREAT) && (semflg & IPC_EXCL) ) {
+#ifdef SEM_DEBUG
+ printf("not exclusive\n");
+#endif
+ return(EEXIST);
+ }
+ } else {
+#ifdef SEM_DEBUG
+ printf("didn't find public key\n");
+#endif
+ }
+ }
+
+ if ( semid == seminfo.semmni ) {
+#ifdef SEM_DEBUG
+ printf("need to allocate the semid_ds\n");
+#endif
+ if ( key == IPC_PRIVATE || (semflg & IPC_CREAT) ) {
+ if ( nsems <= 0 || nsems > seminfo.semmsl ) {
+#ifdef SEM_DEBUG
+ printf("nsems out of range (0<%d<=%d)\n",nsems,seminfo.semmsl);
+#endif
+ return(EINVAL);
+ }
+ if ( nsems > seminfo.semmns - semtot ) {
+#ifdef SEM_DEBUG
+ printf("not enough semaphores left (need %d, got %d)\n",
+ nsems,seminfo.semmns - semtot);
+#endif
+ return(ENOSPC);
+ }
+ for ( semid = 0; semid < seminfo.semmni; semid += 1 ) {
+ if ( (sema[semid].sem_perm.mode & SEM_ALLOC) == 0 ) {
+ break;
+ }
+ }
+ if ( semid == seminfo.semmni ) {
+#ifdef SEM_DEBUG
+ printf("no more semid_ds's available\n");
+#endif
+ return(ENOSPC);
+ }
+#ifdef SEM_DEBUG
+ printf("semid %d is available\n",semid);
+#endif
+ sema[semid].sem_perm.key = key;
+ sema[semid].sem_perm.cuid = cred->cr_uid;
+ sema[semid].sem_perm.uid = cred->cr_uid;
+ sema[semid].sem_perm.cgid = cred->cr_gid;
+ sema[semid].sem_perm.gid = cred->cr_gid;
+ sema[semid].sem_perm.mode = (semflg & 0777) | SEM_ALLOC;
+ sema[semid].sem_perm.seq = (sema[semid].sem_perm.seq + 1) & 0x7fff; /* avoid semid overflows */
+ sema[semid].sem_nsems = nsems;
+ sema[semid].sem_otime = 0;
+ sema[semid].sem_ctime = time.tv_sec;
+ sema[semid].sem_base = &sem[semtot];
+ semtot += nsems;
+ bzero(sema[semid].sem_base,sizeof(sema[semid].sem_base[0])*nsems);
+#ifdef SEM_DEBUG
+ printf("sembase = 0x%x, next = 0x%x\n",sema[semid].sem_base,&sem[semtot]);
+#endif
+ } else {
+#ifdef SEM_DEBUG
+ printf("didn't find it and wasn't asked to create it\n");
+#endif
+ return(ENOENT);
+ }
+ }
+
+ *retval = IXSEQ_TO_IPCID(semid,sema[semid].sem_perm); /* Convert to one origin */
+ return(0);
+}
+
+struct semop_args {
+ int semid;
+ struct sembuf *sops;
+ int nsops;
+};
+
+int
+semop(p, uap, retval)
+ struct proc *p;
+ register struct semop_args *uap;
+ int *retval;
+{
+ int semid = uap->semid;
+ int nsops = uap->nsops;
+ struct sembuf sops[MAX_SOPS];
+ register struct semid_ds *semaptr;
+ register struct sembuf *sopptr;
+ register struct sem *semptr;
+ struct sem_undo *suptr = NULL;
+ struct ucred *cred = p->p_ucred;
+ int i, j, eval;
+ int all_ok, do_wakeup, do_undos;
+
+#ifdef SEM_DEBUG
+ printf("call to semop(%d,0x%x,%d)\n",semid,sops,nsops);
+#endif
+
+ semid = IPCID_TO_IX(semid); /* Convert back to zero origin */
+
+ if ( semid < 0 || semid >= seminfo.semmsl ) {
+ /* printf("semid out of range (0<=%d<%d)\n",semid,seminfo.semmsl); */
+ return(EINVAL);
+ }
+
+ semaptr = &sema[semid];
+ if ( (semaptr->sem_perm.mode & SEM_ALLOC) == 0 ) {
+ /* printf("no such semaphore id\n"); */
+ return(EINVAL);
+ }
+
+ if ( semaptr->sem_perm.seq != IPCID_TO_SEQ(uap->semid) ) {
+ /* printf("invalid sequence number\n"); */
+ return(EINVAL);
+ }
+
+ if ( (eval = ipcaccess(&semaptr->sem_perm, IPC_W, cred)) ) {
+#ifdef SEM_DEBUG
+ printf("eval = %d from ipaccess\n",eval);
+#endif
+ return(eval);
+ }
+
+ if ( nsops > MAX_SOPS ) {
+#ifdef SEM_DEBUG
+ printf("too many sops (max=%d, nsops=%d)\n",MAX_SOPS,nsops);
+#endif
+ return(E2BIG);
+ }
+
+ if ( (eval = copyin(uap->sops, &sops, nsops * sizeof(sops[0]))) != 0 ) {
+#ifdef SEM_DEBUG
+ printf("eval = %d from copyin(%08x, %08x, %d)\n",eval,uap->sops,&sops,nsops * sizeof(sops[0]));
+#endif
+ return(eval);
+ }
+
+ /*
+ * Loop trying to satisfy the vector of requests.
+ * If we reach a point where we must wait, any requests already
+ * performed are rolled back and we go to sleep until some other
+ * process wakes us up. At this point, we start all over again.
+ *
+ * This ensures that from the perspective of other tasks, a set
+ * of requests is atomic (never partially satisfied).
+ */
+
+ do_undos = 0;
+
+ while (1) {
+
+ do_wakeup = 0;
+
+ for ( i = 0; i < nsops; i += 1 ) {
+
+ sopptr = &sops[i];
+
+ if ( sopptr->sem_num >= semaptr->sem_nsems ) {
+ return(EFBIG);
+ }
+
+ semptr = &semaptr->sem_base[sopptr->sem_num];
+
+#ifdef SEM_DEBUG
+ printf("semop: semaptr=%x, sem_base=%x, semptr=%x, sem[%d]=%d : op=%d, flag=%s\n",
+ semaptr,semaptr->sem_base,semptr,
+ sopptr->sem_num,semptr->semval,sopptr->sem_op,
+ (sopptr->sem_flg & IPC_NOWAIT) ? "nowait" : "wait");
+#endif
+
+ if ( sopptr->sem_op < 0 ) {
+
+ if ( semptr->semval + sopptr->sem_op < 0 ) {
+#ifdef SEM_DEBUG
+ printf("semop: can't do it now\n");
+#endif
+ break;
+ } else {
+ semptr->semval += sopptr->sem_op;
+ if ( semptr->semval == 0 && semptr->semzcnt > 0 ) {
+ do_wakeup = 1;
+ }
+ }
+ if ( sopptr->sem_flg & SEM_UNDO ) {
+ do_undos = 1;
+ }
+
+ } else if ( sopptr->sem_op == 0 ) {
+
+ if ( semptr->semval > 0 ) {
+#ifdef SEM_DEBUG
+ printf("semop: not zero now\n");
+#endif
+ break;
+ }
+
+ } else {
+
+ if ( semptr->semncnt > 0 ) {
+ do_wakeup = 1;
+ }
+ semptr->semval += sopptr->sem_op;
+ if ( sopptr->sem_flg & SEM_UNDO ) {
+ do_undos = 1;
+ }
+
+ }
+ }
+
+ /*
+ * Did we get through the entire vector?
+ */
+
+ if ( i < nsops ) {
+
+ /*
+ * No ... rollback anything that we've already done
+ */
+
+#ifdef SEM_DEBUG
+ printf("semop: rollback 0 through %d\n",i-1);
+#endif
+ for ( j = 0; j < i; j += 1 ) {
+ semaptr->sem_base[sops[j].sem_num].semval -= sops[j].sem_op;
+ }
+
+ /*
+ * If the request that we couldn't satisfy has the NOWAIT
+ * flag set then return with EAGAIN.
+ */
+
+ if ( sopptr->sem_flg & IPC_NOWAIT ) {
+ return(EAGAIN);
+ }
+
+ if ( sopptr->sem_op == 0 ) {
+ semptr->semzcnt += 1;
+ } else {
+ semptr->semncnt += 1;
+ }
+
+#ifdef SEM_DEBUG
+ printf("semop: good night!\n");
+#endif
+ eval = tsleep( (caddr_t)semaptr, (PZERO - 4) | PCATCH, "sem wait", 0 );
+#ifdef SEM_DEBUG
+ printf("semop: good morning (eval=%d)!\n",eval);
+#endif
+
+ suptr = NULL; /* The sem_undo may have been reallocated */
+
+ if ( eval != 0 ) {
+ /* printf("semop: interrupted system call\n"); */
+ return( EINTR );
+ }
+#ifdef SEM_DEBUG
+ printf("semop: good morning!\n");
+#endif
+
+ /*
+ * Make sure that the semaphore still exists
+ */
+
+ if ( (semaptr->sem_perm.mode & SEM_ALLOC) == 0
+ || semaptr->sem_perm.seq != IPCID_TO_SEQ(uap->semid) ) {
+
+ /* printf("semaphore id deleted\n"); */
+ /* The man page says to return EIDRM. */
+ /* Unfortunately, BSD doesn't define that code! */
+#ifdef EIDRM
+ return(EIDRM);
+#else
+ return(EINVAL);
+#endif
+ }
+
+ /*
+ * The semaphore is still alive. Readjust the count of
+ * waiting processes.
+ */
+
+ if ( sopptr->sem_op == 0 ) {
+ semptr->semzcnt -= 1;
+ } else {
+ semptr->semncnt -= 1;
+ }
+
+
+ } else {
+
+ /*
+ * Yes ... we're done.
+ * Process any SEM_UNDO requests.
+ */
+
+ if ( do_undos ) {
+
+ for ( i = 0; i < nsops; i += 1 ) {
+
+ /* We only need to deal with SEM_UNDO's for non-zero op's */
+ int adjval;
+
+ if ( (sops[i].sem_flg & SEM_UNDO) != 0 && (adjval = sops[i].sem_op) != 0 ) {
+
+ eval = semundo_adjust(p,&suptr,semid,sops[i].sem_num,-adjval);
+ if ( eval != 0 ) {
+
+ /*
+ * Oh-Oh! We ran out of either sem_undo's or undo's.
+ * Rollback the adjustments to this point and then
+ * rollback the semaphore ups and down so we can
+ * return with an error with all structures restored.
+ * We rollback the undo's in the exact reverse order that
+ * we applied them. This guarantees that we won't run
+ * out of space as we roll things back out.
+ */
+
+ for ( j = i - 1; j >= 0; j -= 1 ) {
+
+ if ( (sops[i].sem_flg & SEM_UNDO) != 0 && (adjval = sops[i].sem_op) != 0 ) {
+
+ if ( semundo_adjust(p,&suptr,semid,sops[j].sem_num,adjval) != 0 ) {
+
+ /* This is impossible! */
+ panic("semop - can't undo undos");
+
+ }
+ }
+
+ } /* loop backwards through sops */
+
+ for ( j = 0; j < nsops; j += 1 ) {
+ semaptr->sem_base[sops[j].sem_num].semval -= sops[j].sem_op;
+ }
+
+#ifdef SEM_DEBUG
+ printf("eval = %d from semundo_adjust\n",eval);
+#endif
+ return( eval );
+
+ } /* semundo_adjust failed */
+
+ } /* if ( SEM_UNDO && adjval != 0 ) */
+
+ } /* loop through the sops */
+
+ } /* if ( do_undos ) */
+
+ /* We're definitely done - set the sempid's */
+
+ for ( i = 0; i < nsops; i += 1 ) {
+
+ sopptr = &sops[i];
+ semptr = &semaptr->sem_base[sopptr->sem_num];
+ semptr->sempid = p->p_pid;
+
+ }
+
+ /* Do a wakeup if any semaphore was up'd. */
+
+ if ( do_wakeup ) {
+#ifdef SEM_DEBUG
+ printf("semop: doing wakeup\n");
+#ifdef SEM_WAKEUP
+ sem_wakeup( (caddr_t)semaptr );
+#else
+ wakeup( (caddr_t)semaptr );
+#endif
+ printf("semop: back from wakeup\n");
+#else
+ wakeup( (caddr_t)semaptr );
+#endif
+ }
+#ifdef SEM_DEBUG
+ printf("semop: done\n");
+#endif
+ *retval = 0;
+ return(0);
+
+ }
+
+ }
+
+ panic("semop: how did we get here???");
+}
+
+/*
+ * Go through the undo structures for this process and apply the
+ * adjustments to semaphores.
+ */
+
+void
+semexit(p)
+ struct proc *p;
+{
+ register struct sem_undo *suptr;
+ register struct sem_undo **supptr;
+ int did_something;
+
+ /*
+ * If somebody else is holding the global semaphore facility lock
+ * then sleep until it is released.
+ */
+
+ while ( semlock_holder != NULL && semlock_holder != p ) {
+#ifdef SEM_DEBUG
+ printf("semaphore facility locked - sleeping ...\n");
+#endif
+ sleep( (caddr_t)&semlock_holder, (PZERO - 4) );
+ }
+
+ did_something = 0;
+
+ /*
+ * Go through the chain of undo vectors looking for one
+ * associated with this process.
+ */
+
+ for ( supptr = &semu_list;
+ (suptr = *supptr) != NULL;
+ supptr = &(suptr->un_next)
+ ) {
+
+ if ( suptr->un_proc == p ) {
+
+#ifdef SEM_DEBUG
+ printf("proc @%08x has undo structure with %d entries\n",p,suptr->un_cnt);
+#endif
+
+ /*
+ * If there are any active undo elements then process them.
+ */
+
+ if ( suptr->un_cnt > 0 ) {
+
+ int ix;
+
+ for ( ix = 0; ix < suptr->un_cnt; ix += 1 ) {
+
+ int semid = suptr->un_ent[ix].un_id;
+ int semnum = suptr->un_ent[ix].un_num;
+ int adjval = suptr->un_ent[ix].un_adjval;
+ struct semid_ds *semaptr;
+
+ semaptr = &sema[semid];
+ if ( (semaptr->sem_perm.mode & SEM_ALLOC) == 0 ) {
+ panic("semexit - semid not allocated");
+ }
+ if ( semnum >= semaptr->sem_nsems ) {
+ panic("semexit - semnum out of range");
+ }
+
+#ifdef SEM_DEBUG
+ printf("semexit: %08x id=%d num=%d(adj=%d) ; sem=%d\n",suptr->un_proc,
+ suptr->un_ent[ix].un_id,suptr->un_ent[ix].un_num,suptr->un_ent[ix].un_adjval,
+ semaptr->sem_base[semnum].semval);
+#endif
+
+ if ( adjval < 0 ) {
+ if ( semaptr->sem_base[semnum].semval < -adjval ) {
+ semaptr->sem_base[semnum].semval = 0;
+ } else {
+ semaptr->sem_base[semnum].semval += adjval;
+ }
+ } else {
+ semaptr->sem_base[semnum].semval += adjval;
+ }
+
+ /* printf("semval now %d\n",semaptr->sem_base[semnum].semval); */
+
+#ifdef SEM_WAKEUP
+ sem_wakeup((caddr_t)semaptr); /* A little sloppy (we should KNOW if anybody is waiting). */
+#else
+ wakeup((caddr_t)semaptr); /* A little sloppy (we should KNOW if anybody is waiting). */
+#endif
+#ifdef SEM_DEBUG
+ printf("semexit: back from wakeup\n");
+#endif
+
+ }
+
+ }
+
+ /*
+ * Deallocate the undo vector.
+ */
+
+#ifdef SEM_DEBUG
+ printf("removing vector\n");
+#endif
+ suptr->un_proc = NULL;
+ *supptr = suptr->un_next;
+
+ /* Done. */
+
+ break;
+
+
+ }
+
+ }
+
+ /*
+ * If the exiting process is holding the global semaphore facility
+ * lock then release it.
+ */
+
+ if ( semlock_holder == p ) {
+ semlock_holder = NULL;
+ wakeup( (caddr_t)&semlock_holder );
+ }
+}
+#endif
generated by cgit v1.2.3 (git 2.25.1) at 2025-10-28 05:54:34 +0000