1157 lines
26 KiB
C
1157 lines
26 KiB
C
/* $FreeBSD$ */
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/*
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* Implementation of SVID semaphores
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*
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* Author: Daniel Boulet
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*
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* This software is provided ``AS IS'' without any warranties of any kind.
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*/
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#include "opt_sysvipc.h"
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/sysproto.h>
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#include <sys/kernel.h>
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#include <sys/proc.h>
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#include <sys/lock.h>
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#include <sys/mutex.h>
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#include <sys/sem.h>
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#include <sys/syscall.h>
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#include <sys/sysent.h>
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#include <sys/sysctl.h>
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#include <sys/malloc.h>
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#include <sys/jail.h>
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static MALLOC_DEFINE(M_SEM, "sem", "SVID compatible semaphores");
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static void seminit __P((void));
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static int sysvsem_modload __P((struct module *, int, void *));
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static int semunload __P((void));
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static void semexit_myhook __P((struct proc *p));
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static int sysctl_sema __P((SYSCTL_HANDLER_ARGS));
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#ifndef _SYS_SYSPROTO_H_
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struct __semctl_args;
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int __semctl __P((struct proc *p, struct __semctl_args *uap));
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struct semget_args;
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int semget __P((struct proc *p, struct semget_args *uap));
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struct semop_args;
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int semop __P((struct proc *p, struct semop_args *uap));
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#endif
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static struct sem_undo *semu_alloc __P((struct proc *p));
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static int semundo_adjust __P((struct proc *p, struct sem_undo **supptr,
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int semid, int semnum, int adjval));
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static void semundo_clear __P((int semid, int semnum));
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/* XXX casting to (sy_call_t *) is bogus, as usual. */
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static sy_call_t *semcalls[] = {
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(sy_call_t *)__semctl, (sy_call_t *)semget,
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(sy_call_t *)semop
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};
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static int semtot = 0;
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static struct semid_ds *sema; /* semaphore id pool */
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static struct sem *sem; /* semaphore pool */
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static struct sem_undo *semu_list; /* list of active undo structures */
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static int *semu; /* undo structure pool */
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struct sem {
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u_short semval; /* semaphore value */
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pid_t sempid; /* pid of last operation */
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u_short semncnt; /* # awaiting semval > cval */
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u_short semzcnt; /* # awaiting semval = 0 */
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};
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/*
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* Undo structure (one per process)
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*/
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struct sem_undo {
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struct sem_undo *un_next; /* ptr to next active undo structure */
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struct proc *un_proc; /* owner of this structure */
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short un_cnt; /* # of active entries */
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struct undo {
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short un_adjval; /* adjust on exit values */
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short un_num; /* semaphore # */
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int un_id; /* semid */
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} un_ent[1]; /* undo entries */
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};
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/*
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* Configuration parameters
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*/
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#ifndef SEMMNI
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#define SEMMNI 10 /* # of semaphore identifiers */
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#endif
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#ifndef SEMMNS
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#define SEMMNS 60 /* # of semaphores in system */
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#endif
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#ifndef SEMUME
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#define SEMUME 10 /* max # of undo entries per process */
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#endif
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#ifndef SEMMNU
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#define SEMMNU 30 /* # of undo structures in system */
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#endif
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/* shouldn't need tuning */
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#ifndef SEMMAP
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#define SEMMAP 30 /* # of entries in semaphore map */
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#endif
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#ifndef SEMMSL
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#define SEMMSL SEMMNS /* max # of semaphores per id */
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#endif
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#ifndef SEMOPM
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#define SEMOPM 100 /* max # of operations per semop call */
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#endif
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#define SEMVMX 32767 /* semaphore maximum value */
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#define SEMAEM 16384 /* adjust on exit max value */
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/*
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* Due to the way semaphore memory is allocated, we have to ensure that
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* SEMUSZ is properly aligned.
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*/
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#define SEM_ALIGN(bytes) (((bytes) + (sizeof(long) - 1)) & ~(sizeof(long) - 1))
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/* actual size of an undo structure */
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#define SEMUSZ SEM_ALIGN(offsetof(struct sem_undo, un_ent[SEMUME]))
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/*
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* Macro to find a particular sem_undo vector
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*/
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#define SEMU(ix) ((struct sem_undo *)(((intptr_t)semu)+ix * seminfo.semusz))
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/*
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* semaphore info struct
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*/
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struct seminfo seminfo = {
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SEMMAP, /* # of entries in semaphore map */
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SEMMNI, /* # of semaphore identifiers */
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SEMMNS, /* # of semaphores in system */
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SEMMNU, /* # of undo structures in system */
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SEMMSL, /* max # of semaphores per id */
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SEMOPM, /* max # of operations per semop call */
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SEMUME, /* max # of undo entries per process */
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SEMUSZ, /* size in bytes of undo structure */
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SEMVMX, /* semaphore maximum value */
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SEMAEM /* adjust on exit max value */
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};
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SYSCTL_DECL(_kern_ipc);
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SYSCTL_INT(_kern_ipc, OID_AUTO, semmap, CTLFLAG_RW, &seminfo.semmap, 0, "");
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SYSCTL_INT(_kern_ipc, OID_AUTO, semmni, CTLFLAG_RD, &seminfo.semmni, 0, "");
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SYSCTL_INT(_kern_ipc, OID_AUTO, semmns, CTLFLAG_RD, &seminfo.semmns, 0, "");
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SYSCTL_INT(_kern_ipc, OID_AUTO, semmnu, CTLFLAG_RD, &seminfo.semmnu, 0, "");
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SYSCTL_INT(_kern_ipc, OID_AUTO, semmsl, CTLFLAG_RW, &seminfo.semmsl, 0, "");
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SYSCTL_INT(_kern_ipc, OID_AUTO, semopm, CTLFLAG_RD, &seminfo.semopm, 0, "");
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SYSCTL_INT(_kern_ipc, OID_AUTO, semume, CTLFLAG_RD, &seminfo.semume, 0, "");
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SYSCTL_INT(_kern_ipc, OID_AUTO, semusz, CTLFLAG_RD, &seminfo.semusz, 0, "");
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SYSCTL_INT(_kern_ipc, OID_AUTO, semvmx, CTLFLAG_RW, &seminfo.semvmx, 0, "");
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SYSCTL_INT(_kern_ipc, OID_AUTO, semaem, CTLFLAG_RW, &seminfo.semaem, 0, "");
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SYSCTL_PROC(_kern_ipc, OID_AUTO, sema, CTLFLAG_RD,
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NULL, 0, sysctl_sema, "", "");
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#if 0
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RO seminfo.semmap /* SEMMAP unused */
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RO seminfo.semmni
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RO seminfo.semmns
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RO seminfo.semmnu /* undo entries per system */
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RW seminfo.semmsl
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RO seminfo.semopm /* SEMOPM unused */
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RO seminfo.semume
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RO seminfo.semusz /* param - derived from SEMUME for per-proc sizeof */
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RO seminfo.semvmx /* SEMVMX unused - user param */
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RO seminfo.semaem /* SEMAEM unused - user param */
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#endif
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static void
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seminit(void)
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{
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register int i;
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sem = malloc(sizeof(struct sem) * seminfo.semmns, M_SEM, M_WAITOK);
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if (sem == NULL)
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panic("sem is NULL");
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sema = malloc(sizeof(struct semid_ds) * seminfo.semmni, M_SEM, M_WAITOK);
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if (sema == NULL)
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panic("sema is NULL");
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semu = malloc(seminfo.semmnu * seminfo.semusz, M_SEM, M_WAITOK);
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if (semu == NULL)
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panic("semu is NULL");
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for (i = 0; i < seminfo.semmni; i++) {
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sema[i].sem_base = 0;
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sema[i].sem_perm.mode = 0;
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}
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for (i = 0; i < seminfo.semmnu; i++) {
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register struct sem_undo *suptr = SEMU(i);
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suptr->un_proc = NULL;
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}
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semu_list = NULL;
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semexit_hook = &semexit_myhook;
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}
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static int
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semunload(void)
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{
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if (semtot != 0)
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return (EBUSY);
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free(sem, M_SEM);
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free(sema, M_SEM);
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free(semu, M_SEM);
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semexit_hook = NULL;
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return (0);
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}
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static int
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sysvsem_modload(struct module *module, int cmd, void *arg)
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{
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int error = 0;
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switch (cmd) {
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case MOD_LOAD:
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seminit();
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break;
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case MOD_UNLOAD:
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error = semunload();
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break;
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case MOD_SHUTDOWN:
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break;
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default:
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error = EINVAL;
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break;
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}
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return (error);
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}
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static moduledata_t sysvsem_mod = {
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"sysvsem",
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&sysvsem_modload,
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NULL
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};
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SYSCALL_MODULE_HELPER(semsys, 5);
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SYSCALL_MODULE_HELPER(__semctl, 4);
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SYSCALL_MODULE_HELPER(semget, 3);
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SYSCALL_MODULE_HELPER(semop, 3);
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DECLARE_MODULE(sysvsem, sysvsem_mod,
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SI_SUB_SYSV_SEM, SI_ORDER_FIRST);
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MODULE_VERSION(sysvsem, 1);
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/*
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* Entry point for all SEM calls
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*
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* MPSAFE
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*/
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int
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semsys(p, uap)
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struct proc *p;
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/* XXX actually varargs. */
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struct semsys_args /* {
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u_int which;
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int a2;
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int a3;
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int a4;
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int a5;
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} */ *uap;
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{
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int error;
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mtx_lock(&Giant);
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if (!jail_sysvipc_allowed && jailed(p->p_ucred)) {
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error = ENOSYS;
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goto done2;
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}
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if (uap->which >= sizeof(semcalls)/sizeof(semcalls[0])) {
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error = EINVAL;
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goto done2;
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}
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error = (*semcalls[uap->which])(p, &uap->a2);
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done2:
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mtx_unlock(&Giant);
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return (error);
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}
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/*
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* Allocate a new sem_undo structure for a process
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* (returns ptr to structure or NULL if no more room)
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*/
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static struct sem_undo *
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semu_alloc(p)
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struct proc *p;
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{
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register int i;
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register struct sem_undo *suptr;
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register struct sem_undo **supptr;
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int attempt;
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/*
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* Try twice to allocate something.
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* (we'll purge any empty structures after the first pass so
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* two passes are always enough)
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*/
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for (attempt = 0; attempt < 2; attempt++) {
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/*
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* Look for a free structure.
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* Fill it in and return it if we find one.
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*/
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for (i = 0; i < seminfo.semmnu; i++) {
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suptr = SEMU(i);
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if (suptr->un_proc == NULL) {
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suptr->un_next = semu_list;
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semu_list = suptr;
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suptr->un_cnt = 0;
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suptr->un_proc = p;
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return(suptr);
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}
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}
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/*
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* We didn't find a free one, if this is the first attempt
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* then try to free some structures.
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*/
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if (attempt == 0) {
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/* All the structures are in use - try to free some */
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int did_something = 0;
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supptr = &semu_list;
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while ((suptr = *supptr) != NULL) {
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if (suptr->un_cnt == 0) {
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suptr->un_proc = NULL;
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*supptr = suptr->un_next;
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did_something = 1;
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} else
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supptr = &(suptr->un_next);
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}
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/* If we didn't free anything then just give-up */
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if (!did_something)
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return(NULL);
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} else {
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/*
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* The second pass failed even though we freed
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* something after the first pass!
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* This is IMPOSSIBLE!
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*/
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panic("semu_alloc - second attempt failed");
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}
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}
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return (NULL);
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}
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/*
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* Adjust a particular entry for a particular proc
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*/
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static int
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semundo_adjust(p, supptr, semid, semnum, adjval)
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register struct proc *p;
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struct sem_undo **supptr;
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int semid, semnum;
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int adjval;
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{
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register struct sem_undo *suptr;
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register struct undo *sunptr;
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int i;
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/* Look for and remember the sem_undo if the caller doesn't provide
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it */
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suptr = *supptr;
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if (suptr == NULL) {
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for (suptr = semu_list; suptr != NULL;
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suptr = suptr->un_next) {
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if (suptr->un_proc == p) {
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*supptr = suptr;
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break;
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}
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}
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if (suptr == NULL) {
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if (adjval == 0)
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return(0);
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suptr = semu_alloc(p);
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if (suptr == NULL)
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return(ENOSPC);
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*supptr = suptr;
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}
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}
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/*
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* Look for the requested entry and adjust it (delete if adjval becomes
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* 0).
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*/
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sunptr = &suptr->un_ent[0];
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for (i = 0; i < suptr->un_cnt; i++, sunptr++) {
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if (sunptr->un_id != semid || sunptr->un_num != semnum)
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continue;
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if (adjval == 0)
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sunptr->un_adjval = 0;
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else
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sunptr->un_adjval += adjval;
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if (sunptr->un_adjval == 0) {
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suptr->un_cnt--;
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if (i < suptr->un_cnt)
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suptr->un_ent[i] =
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suptr->un_ent[suptr->un_cnt];
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}
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return(0);
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}
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/* Didn't find the right entry - create it */
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if (adjval == 0)
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return(0);
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if (suptr->un_cnt != seminfo.semume) {
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sunptr = &suptr->un_ent[suptr->un_cnt];
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suptr->un_cnt++;
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sunptr->un_adjval = adjval;
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sunptr->un_id = semid; sunptr->un_num = semnum;
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} else
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return(EINVAL);
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return(0);
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}
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static void
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semundo_clear(semid, semnum)
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int semid, semnum;
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{
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register struct sem_undo *suptr;
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for (suptr = semu_list; suptr != NULL; suptr = suptr->un_next) {
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register struct undo *sunptr = &suptr->un_ent[0];
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register int i = 0;
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while (i < suptr->un_cnt) {
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if (sunptr->un_id == semid) {
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if (semnum == -1 || sunptr->un_num == semnum) {
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suptr->un_cnt--;
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if (i < suptr->un_cnt) {
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suptr->un_ent[i] =
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suptr->un_ent[suptr->un_cnt];
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continue;
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}
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}
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if (semnum != -1)
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break;
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}
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i++, sunptr++;
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}
|
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}
|
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}
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|
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/*
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* Note that the user-mode half of this passes a union, not a pointer
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*/
|
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#ifndef _SYS_SYSPROTO_H_
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struct __semctl_args {
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int semid;
|
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int semnum;
|
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int cmd;
|
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union semun *arg;
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};
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#endif
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|
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/*
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* MPSAFE
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*/
|
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int
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__semctl(p, uap)
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struct proc *p;
|
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register struct __semctl_args *uap;
|
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{
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int semid = uap->semid;
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int semnum = uap->semnum;
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int cmd = uap->cmd;
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union semun *arg = uap->arg;
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union semun real_arg;
|
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struct ucred *cred = p->p_ucred;
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int i, rval, error;
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struct semid_ds sbuf;
|
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register struct semid_ds *semaptr;
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|
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#ifdef SEM_DEBUG
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printf("call to semctl(%d, %d, %d, 0x%x)\n", semid, semnum, cmd, arg);
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#endif
|
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mtx_lock(&Giant);
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|
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if (!jail_sysvipc_allowed && jailed(p->p_ucred)) {
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error = ENOSYS;
|
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goto done2;
|
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}
|
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|
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semid = IPCID_TO_IX(semid);
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if (semid < 0 || semid >= seminfo.semmsl) {
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error = EINVAL;
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goto done2;
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}
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|
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semaptr = &sema[semid];
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if ((semaptr->sem_perm.mode & SEM_ALLOC) == 0 ||
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semaptr->sem_perm.seq != IPCID_TO_SEQ(uap->semid)) {
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error = EINVAL;
|
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goto done2;
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}
|
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|
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error = 0;
|
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rval = 0;
|
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|
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switch (cmd) {
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case IPC_RMID:
|
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if ((error = ipcperm(p, &semaptr->sem_perm, IPC_M)))
|
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goto done2;
|
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semaptr->sem_perm.cuid = cred->cr_uid;
|
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semaptr->sem_perm.uid = cred->cr_uid;
|
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semtot -= semaptr->sem_nsems;
|
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for (i = semaptr->sem_base - sem; i < semtot; i++)
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sem[i] = sem[i + semaptr->sem_nsems];
|
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for (i = 0; i < seminfo.semmni; i++) {
|
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if ((sema[i].sem_perm.mode & SEM_ALLOC) &&
|
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sema[i].sem_base > semaptr->sem_base)
|
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sema[i].sem_base -= semaptr->sem_nsems;
|
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}
|
|
semaptr->sem_perm.mode = 0;
|
|
semundo_clear(semid, -1);
|
|
wakeup((caddr_t)semaptr);
|
|
break;
|
|
|
|
case IPC_SET:
|
|
if ((error = ipcperm(p, &semaptr->sem_perm, IPC_M)))
|
|
goto done2;
|
|
if ((error = copyin(arg, &real_arg, sizeof(real_arg))) != 0)
|
|
goto done2;
|
|
if ((error = copyin(real_arg.buf, (caddr_t)&sbuf,
|
|
sizeof(sbuf))) != 0) {
|
|
goto done2;
|
|
}
|
|
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_second;
|
|
break;
|
|
|
|
case IPC_STAT:
|
|
if ((error = ipcperm(p, &semaptr->sem_perm, IPC_R)))
|
|
goto done2;
|
|
if ((error = copyin(arg, &real_arg, sizeof(real_arg))) != 0)
|
|
goto done2;
|
|
error = copyout((caddr_t)semaptr, real_arg.buf,
|
|
sizeof(struct semid_ds));
|
|
break;
|
|
|
|
case GETNCNT:
|
|
if ((error = ipcperm(p, &semaptr->sem_perm, IPC_R)))
|
|
goto done2;
|
|
if (semnum < 0 || semnum >= semaptr->sem_nsems) {
|
|
error = EINVAL;
|
|
goto done2;
|
|
}
|
|
rval = semaptr->sem_base[semnum].semncnt;
|
|
break;
|
|
|
|
case GETPID:
|
|
if ((error = ipcperm(p, &semaptr->sem_perm, IPC_R)))
|
|
goto done2;
|
|
if (semnum < 0 || semnum >= semaptr->sem_nsems) {
|
|
error = EINVAL;
|
|
goto done2;
|
|
}
|
|
rval = semaptr->sem_base[semnum].sempid;
|
|
break;
|
|
|
|
case GETVAL:
|
|
if ((error = ipcperm(p, &semaptr->sem_perm, IPC_R)))
|
|
goto done2;
|
|
if (semnum < 0 || semnum >= semaptr->sem_nsems) {
|
|
error = EINVAL;
|
|
goto done2;
|
|
}
|
|
rval = semaptr->sem_base[semnum].semval;
|
|
break;
|
|
|
|
case GETALL:
|
|
if ((error = ipcperm(p, &semaptr->sem_perm, IPC_R)))
|
|
goto done2;
|
|
if ((error = copyin(arg, &real_arg, sizeof(real_arg))) != 0)
|
|
goto done2;
|
|
for (i = 0; i < semaptr->sem_nsems; i++) {
|
|
error = copyout((caddr_t)&semaptr->sem_base[i].semval,
|
|
&real_arg.array[i], sizeof(real_arg.array[0]));
|
|
if (error != 0)
|
|
break;
|
|
}
|
|
break;
|
|
|
|
case GETZCNT:
|
|
if ((error = ipcperm(p, &semaptr->sem_perm, IPC_R)))
|
|
goto done2;
|
|
if (semnum < 0 || semnum >= semaptr->sem_nsems) {
|
|
error = EINVAL;
|
|
goto done2;
|
|
}
|
|
rval = semaptr->sem_base[semnum].semzcnt;
|
|
break;
|
|
|
|
case SETVAL:
|
|
if ((error = ipcperm(p, &semaptr->sem_perm, IPC_W)))
|
|
goto done2;
|
|
if (semnum < 0 || semnum >= semaptr->sem_nsems) {
|
|
error = EINVAL;
|
|
goto done2;
|
|
}
|
|
if ((error = copyin(arg, &real_arg, sizeof(real_arg))) != 0)
|
|
goto done2;
|
|
semaptr->sem_base[semnum].semval = real_arg.val;
|
|
semundo_clear(semid, semnum);
|
|
wakeup((caddr_t)semaptr);
|
|
break;
|
|
|
|
case SETALL:
|
|
if ((error = ipcperm(p, &semaptr->sem_perm, IPC_W)))
|
|
goto done2;
|
|
if ((error = copyin(arg, &real_arg, sizeof(real_arg))) != 0)
|
|
goto done2;
|
|
for (i = 0; i < semaptr->sem_nsems; i++) {
|
|
error = copyin(&real_arg.array[i],
|
|
(caddr_t)&semaptr->sem_base[i].semval,
|
|
sizeof(real_arg.array[0]));
|
|
if (error != 0)
|
|
break;
|
|
}
|
|
semundo_clear(semid, -1);
|
|
wakeup((caddr_t)semaptr);
|
|
break;
|
|
|
|
default:
|
|
error = EINVAL;
|
|
break;
|
|
}
|
|
|
|
if (error == 0)
|
|
p->p_retval[0] = rval;
|
|
done2:
|
|
mtx_unlock(&Giant);
|
|
return(error);
|
|
}
|
|
|
|
#ifndef _SYS_SYSPROTO_H_
|
|
struct semget_args {
|
|
key_t key;
|
|
int nsems;
|
|
int semflg;
|
|
};
|
|
#endif
|
|
|
|
/*
|
|
* MPSAFE
|
|
*/
|
|
int
|
|
semget(p, uap)
|
|
struct proc *p;
|
|
register struct semget_args *uap;
|
|
{
|
|
int semid, error = 0;
|
|
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
|
|
mtx_lock(&Giant);
|
|
|
|
if (!jail_sysvipc_allowed && jailed(p->p_ucred)) {
|
|
error = ENOSYS;
|
|
goto done2;
|
|
}
|
|
|
|
if (key != IPC_PRIVATE) {
|
|
for (semid = 0; semid < seminfo.semmni; semid++) {
|
|
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 ((error = ipcperm(p, &sema[semid].sem_perm,
|
|
semflg & 0700))) {
|
|
goto done2;
|
|
}
|
|
if (nsems > 0 && sema[semid].sem_nsems < nsems) {
|
|
#ifdef SEM_DEBUG
|
|
printf("too small\n");
|
|
#endif
|
|
error = EINVAL;
|
|
goto done2;
|
|
}
|
|
if ((semflg & IPC_CREAT) && (semflg & IPC_EXCL)) {
|
|
#ifdef SEM_DEBUG
|
|
printf("not exclusive\n");
|
|
#endif
|
|
error = EEXIST;
|
|
goto done2;
|
|
}
|
|
goto found;
|
|
}
|
|
}
|
|
|
|
#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
|
|
error = EINVAL;
|
|
goto done2;
|
|
}
|
|
if (nsems > seminfo.semmns - semtot) {
|
|
#ifdef SEM_DEBUG
|
|
printf("not enough semaphores left (need %d, got %d)\n",
|
|
nsems, seminfo.semmns - semtot);
|
|
#endif
|
|
error = ENOSPC;
|
|
goto done2;
|
|
}
|
|
for (semid = 0; semid < seminfo.semmni; semid++) {
|
|
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
|
|
error = ENOSPC;
|
|
goto done2;
|
|
}
|
|
#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;
|
|
sema[semid].sem_nsems = nsems;
|
|
sema[semid].sem_otime = 0;
|
|
sema[semid].sem_ctime = time_second;
|
|
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
|
|
error = ENOENT;
|
|
goto done2;
|
|
}
|
|
|
|
found:
|
|
p->p_retval[0] = IXSEQ_TO_IPCID(semid, sema[semid].sem_perm);
|
|
done2:
|
|
mtx_unlock(&Giant);
|
|
return (error);
|
|
}
|
|
|
|
#ifndef _SYS_SYSPROTO_H_
|
|
struct semop_args {
|
|
int semid;
|
|
struct sembuf *sops;
|
|
int nsops;
|
|
};
|
|
#endif
|
|
|
|
/*
|
|
* MPSAFE
|
|
*/
|
|
int
|
|
semop(p, uap)
|
|
struct proc *p;
|
|
register struct semop_args *uap;
|
|
{
|
|
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;
|
|
int i, j, error = 0;
|
|
int do_wakeup, do_undos;
|
|
|
|
#ifdef SEM_DEBUG
|
|
printf("call to semop(%d, 0x%x, %d)\n", semid, sops, nsops);
|
|
#endif
|
|
|
|
mtx_lock(&Giant);
|
|
|
|
if (!jail_sysvipc_allowed && jailed(p->p_ucred)) {
|
|
error = ENOSYS;
|
|
goto done2;
|
|
}
|
|
|
|
semid = IPCID_TO_IX(semid); /* Convert back to zero origin */
|
|
|
|
if (semid < 0 || semid >= seminfo.semmsl) {
|
|
error = EINVAL;
|
|
goto done2;
|
|
}
|
|
|
|
semaptr = &sema[semid];
|
|
if ((semaptr->sem_perm.mode & SEM_ALLOC) == 0) {
|
|
error = EINVAL;
|
|
goto done2;
|
|
}
|
|
if (semaptr->sem_perm.seq != IPCID_TO_SEQ(uap->semid)) {
|
|
error = EINVAL;
|
|
goto done2;
|
|
}
|
|
|
|
if ((error = ipcperm(p, &semaptr->sem_perm, IPC_W))) {
|
|
#ifdef SEM_DEBUG
|
|
printf("error = %d from ipaccess\n", error);
|
|
#endif
|
|
goto done2;
|
|
}
|
|
|
|
if (nsops > MAX_SOPS) {
|
|
#ifdef SEM_DEBUG
|
|
printf("too many sops (max=%d, nsops=%d)\n", MAX_SOPS, nsops);
|
|
#endif
|
|
error = E2BIG;
|
|
goto done2;
|
|
}
|
|
|
|
if ((error = copyin(uap->sops, &sops, nsops * sizeof(sops[0]))) != 0) {
|
|
#ifdef SEM_DEBUG
|
|
printf("error = %d from copyin(%08x, %08x, %d)\n", error,
|
|
uap->sops, &sops, nsops * sizeof(sops[0]));
|
|
#endif
|
|
goto done2;
|
|
}
|
|
|
|
/*
|
|
* 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;
|
|
|
|
for (;;) {
|
|
do_wakeup = 0;
|
|
|
|
for (i = 0; i < nsops; i++) {
|
|
sopptr = &sops[i];
|
|
|
|
if (sopptr->sem_num >= semaptr->sem_nsems) {
|
|
error = EFBIG;
|
|
goto done2;
|
|
}
|
|
|
|
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)
|
|
goto done;
|
|
|
|
/*
|
|
* 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++)
|
|
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) {
|
|
error = EAGAIN;
|
|
goto done2;
|
|
}
|
|
|
|
if (sopptr->sem_op == 0)
|
|
semptr->semzcnt++;
|
|
else
|
|
semptr->semncnt++;
|
|
|
|
#ifdef SEM_DEBUG
|
|
printf("semop: good night!\n");
|
|
#endif
|
|
error = tsleep((caddr_t)semaptr, (PZERO - 4) | PCATCH,
|
|
"semwait", 0);
|
|
#ifdef SEM_DEBUG
|
|
printf("semop: good morning (error=%d)!\n", error);
|
|
#endif
|
|
|
|
suptr = NULL; /* sem_undo may have been reallocated */
|
|
|
|
if (error != 0) {
|
|
error = EINTR;
|
|
goto done2;
|
|
}
|
|
#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)) {
|
|
error = EIDRM;
|
|
goto done2;
|
|
}
|
|
|
|
/*
|
|
* The semaphore is still alive. Readjust the count of
|
|
* waiting processes.
|
|
*/
|
|
if (sopptr->sem_op == 0)
|
|
semptr->semzcnt--;
|
|
else
|
|
semptr->semncnt--;
|
|
}
|
|
|
|
done:
|
|
/*
|
|
* Process any SEM_UNDO requests.
|
|
*/
|
|
if (do_undos) {
|
|
for (i = 0; i < nsops; i++) {
|
|
/*
|
|
* We only need to deal with SEM_UNDO's for non-zero
|
|
* op's.
|
|
*/
|
|
int adjval;
|
|
|
|
if ((sops[i].sem_flg & SEM_UNDO) == 0)
|
|
continue;
|
|
adjval = sops[i].sem_op;
|
|
if (adjval == 0)
|
|
continue;
|
|
error = semundo_adjust(p, &suptr, semid,
|
|
sops[i].sem_num, -adjval);
|
|
if (error == 0)
|
|
continue;
|
|
|
|
/*
|
|
* 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--) {
|
|
if ((sops[j].sem_flg & SEM_UNDO) == 0)
|
|
continue;
|
|
adjval = sops[j].sem_op;
|
|
if (adjval == 0)
|
|
continue;
|
|
if (semundo_adjust(p, &suptr, semid,
|
|
sops[j].sem_num, adjval) != 0)
|
|
panic("semop - can't undo undos");
|
|
}
|
|
|
|
for (j = 0; j < nsops; j++)
|
|
semaptr->sem_base[sops[j].sem_num].semval -=
|
|
sops[j].sem_op;
|
|
|
|
#ifdef SEM_DEBUG
|
|
printf("error = %d from semundo_adjust\n", error);
|
|
#endif
|
|
goto done2;
|
|
} /* loop through the sops */
|
|
} /* if (do_undos) */
|
|
|
|
/* We're definitely done - set the sempid's */
|
|
for (i = 0; i < nsops; i++) {
|
|
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");
|
|
#endif
|
|
wakeup((caddr_t)semaptr);
|
|
#ifdef SEM_DEBUG
|
|
printf("semop: back from wakeup\n");
|
|
#endif
|
|
}
|
|
#ifdef SEM_DEBUG
|
|
printf("semop: done\n");
|
|
#endif
|
|
p->p_retval[0] = 0;
|
|
done2:
|
|
mtx_unlock(&Giant);
|
|
return (error);
|
|
}
|
|
|
|
/*
|
|
* Go through the undo structures for this process and apply the adjustments to
|
|
* semaphores.
|
|
*/
|
|
static void
|
|
semexit_myhook(p)
|
|
struct proc *p;
|
|
{
|
|
register struct sem_undo *suptr;
|
|
register struct sem_undo **supptr;
|
|
int did_something;
|
|
|
|
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)
|
|
break;
|
|
}
|
|
|
|
if (suptr == NULL)
|
|
return;
|
|
|
|
#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++) {
|
|
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;
|
|
|
|
wakeup((caddr_t)semaptr);
|
|
#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;
|
|
}
|
|
|
|
static int
|
|
sysctl_sema(SYSCTL_HANDLER_ARGS)
|
|
{
|
|
|
|
return (SYSCTL_OUT(req, sema,
|
|
sizeof(struct semid_ds) * seminfo.semmni));
|
|
}
|