1350 lines
34 KiB
C
1350 lines
34 KiB
C
/*-
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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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/*-
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* Copyright (c) 2003-2005 McAfee, Inc.
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* All rights reserved.
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*
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* This software was developed for the FreeBSD Project in part by McAfee
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* Research, the Security Research Division of McAfee, Inc under DARPA/SPAWAR
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* contract N66001-01-C-8035 ("CBOSS"), as part of the DARPA CHATS research
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* program.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include "opt_sysvipc.h"
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#include "opt_mac.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/eventhandler.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/module.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/syscallsubr.h>
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#include <sys/sysent.h>
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#include <sys/sysctl.h>
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#include <sys/uio.h>
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#include <sys/malloc.h>
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#include <sys/jail.h>
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#include <security/mac/mac_framework.h>
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static MALLOC_DEFINE(M_SEM, "sem", "SVID compatible semaphores");
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#ifdef SEM_DEBUG
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#define DPRINTF(a) printf a
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#else
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#define DPRINTF(a)
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#endif
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static void seminit(void);
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static int sysvsem_modload(struct module *, int, void *);
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static int semunload(void);
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static void semexit_myhook(void *arg, struct proc *p);
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static int sysctl_sema(SYSCTL_HANDLER_ARGS);
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static int semvalid(int semid, struct semid_kernel *semakptr);
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#ifndef _SYS_SYSPROTO_H_
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struct __semctl_args;
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int __semctl(struct thread *td, struct __semctl_args *uap);
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struct semget_args;
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int semget(struct thread *td, struct semget_args *uap);
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struct semop_args;
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int semop(struct thread *td, struct semop_args *uap);
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#endif
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static struct sem_undo *semu_alloc(struct thread *td);
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static int semundo_adjust(struct thread *td, struct sem_undo **supptr,
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int semid, int semseq, int semnum, int adjval);
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static void semundo_clear(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 struct mtx sem_mtx; /* semaphore global lock */
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static struct mtx sem_undo_mtx;
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static int semtot = 0;
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static struct semid_kernel *sema; /* semaphore id pool */
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static struct mtx *sema_mtx; /* semaphore id pool mutexes*/
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static struct sem *sem; /* semaphore pool */
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LIST_HEAD(, sem_undo) semu_list; /* list of active undo structures */
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LIST_HEAD(, sem_undo) semu_free_list; /* list of free undo structures */
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static int *semu; /* undo structure pool */
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static eventhandler_tag semexit_tag;
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#define SEMUNDO_MTX sem_undo_mtx
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#define SEMUNDO_LOCK() mtx_lock(&SEMUNDO_MTX);
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#define SEMUNDO_UNLOCK() mtx_unlock(&SEMUNDO_MTX);
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#define SEMUNDO_LOCKASSERT(how) mtx_assert(&SEMUNDO_MTX, (how));
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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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LIST_ENTRY(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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unsigned short un_seq;
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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) \
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((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_INT(_kern_ipc, OID_AUTO, semmap, CTLFLAG_RW, &seminfo.semmap, 0,
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"Number of entries in the semaphore map");
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SYSCTL_INT(_kern_ipc, OID_AUTO, semmni, CTLFLAG_RDTUN, &seminfo.semmni, 0,
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"Number of semaphore identifiers");
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SYSCTL_INT(_kern_ipc, OID_AUTO, semmns, CTLFLAG_RDTUN, &seminfo.semmns, 0,
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"Maximum number of semaphores in the system");
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SYSCTL_INT(_kern_ipc, OID_AUTO, semmnu, CTLFLAG_RDTUN, &seminfo.semmnu, 0,
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"Maximum number of undo structures in the system");
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SYSCTL_INT(_kern_ipc, OID_AUTO, semmsl, CTLFLAG_RW, &seminfo.semmsl, 0,
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"Max semaphores per id");
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SYSCTL_INT(_kern_ipc, OID_AUTO, semopm, CTLFLAG_RDTUN, &seminfo.semopm, 0,
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"Max operations per semop call");
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SYSCTL_INT(_kern_ipc, OID_AUTO, semume, CTLFLAG_RDTUN, &seminfo.semume, 0,
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"Max undo entries per process");
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SYSCTL_INT(_kern_ipc, OID_AUTO, semusz, CTLFLAG_RDTUN, &seminfo.semusz, 0,
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"Size in bytes of undo structure");
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SYSCTL_INT(_kern_ipc, OID_AUTO, semvmx, CTLFLAG_RW, &seminfo.semvmx, 0,
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"Semaphore maximum value");
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SYSCTL_INT(_kern_ipc, OID_AUTO, semaem, CTLFLAG_RW, &seminfo.semaem, 0,
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"Adjust on exit max value");
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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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static void
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seminit(void)
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{
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int i;
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TUNABLE_INT_FETCH("kern.ipc.semmap", &seminfo.semmap);
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TUNABLE_INT_FETCH("kern.ipc.semmni", &seminfo.semmni);
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TUNABLE_INT_FETCH("kern.ipc.semmns", &seminfo.semmns);
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TUNABLE_INT_FETCH("kern.ipc.semmnu", &seminfo.semmnu);
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TUNABLE_INT_FETCH("kern.ipc.semmsl", &seminfo.semmsl);
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TUNABLE_INT_FETCH("kern.ipc.semopm", &seminfo.semopm);
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TUNABLE_INT_FETCH("kern.ipc.semume", &seminfo.semume);
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TUNABLE_INT_FETCH("kern.ipc.semusz", &seminfo.semusz);
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TUNABLE_INT_FETCH("kern.ipc.semvmx", &seminfo.semvmx);
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TUNABLE_INT_FETCH("kern.ipc.semaem", &seminfo.semaem);
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sem = malloc(sizeof(struct sem) * seminfo.semmns, M_SEM, M_WAITOK);
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sema = malloc(sizeof(struct semid_kernel) * seminfo.semmni, M_SEM,
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M_WAITOK);
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sema_mtx = malloc(sizeof(struct mtx) * seminfo.semmni, M_SEM,
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M_WAITOK | M_ZERO);
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semu = malloc(seminfo.semmnu * seminfo.semusz, M_SEM, M_WAITOK);
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for (i = 0; i < seminfo.semmni; i++) {
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sema[i].u.sem_base = 0;
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sema[i].u.sem_perm.mode = 0;
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sema[i].u.sem_perm.seq = 0;
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#ifdef MAC
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mac_sysvsem_init(&sema[i]);
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#endif
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}
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for (i = 0; i < seminfo.semmni; i++)
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mtx_init(&sema_mtx[i], "semid", NULL, MTX_DEF);
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LIST_INIT(&semu_free_list);
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for (i = 0; i < seminfo.semmnu; i++) {
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struct sem_undo *suptr = SEMU(i);
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suptr->un_proc = NULL;
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LIST_INSERT_HEAD(&semu_free_list, suptr, un_next);
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}
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LIST_INIT(&semu_list);
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mtx_init(&sem_mtx, "sem", NULL, MTX_DEF);
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mtx_init(&sem_undo_mtx, "semu", NULL, MTX_DEF);
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semexit_tag = EVENTHANDLER_REGISTER(process_exit, semexit_myhook, NULL,
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EVENTHANDLER_PRI_ANY);
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}
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static int
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semunload(void)
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{
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int i;
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/* XXXKIB */
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if (semtot != 0)
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return (EBUSY);
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EVENTHANDLER_DEREGISTER(process_exit, semexit_tag);
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#ifdef MAC
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for (i = 0; i < seminfo.semmni; i++)
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mac_sysvsem_destroy(&sema[i]);
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#endif
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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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for (i = 0; i < seminfo.semmni; i++)
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mtx_destroy(&sema_mtx[i]);
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free(sema_mtx, M_SEM);
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mtx_destroy(&sem_mtx);
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mtx_destroy(&sem_undo_mtx);
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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);
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SYSCALL_MODULE_HELPER(__semctl);
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SYSCALL_MODULE_HELPER(semget);
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SYSCALL_MODULE_HELPER(semop);
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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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int
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semsys(td, uap)
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struct thread *td;
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/* XXX actually varargs. */
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struct semsys_args /* {
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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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if (!jail_sysvipc_allowed && jailed(td->td_ucred))
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return (ENOSYS);
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if (uap->which < 0 ||
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uap->which >= sizeof(semcalls)/sizeof(semcalls[0]))
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return (EINVAL);
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error = (*semcalls[uap->which])(td, &uap->a2);
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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(struct thread *td)
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{
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struct sem_undo *suptr;
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SEMUNDO_LOCKASSERT(MA_OWNED);
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if ((suptr = LIST_FIRST(&semu_free_list)) == NULL)
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return (NULL);
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LIST_REMOVE(suptr, un_next);
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LIST_INSERT_HEAD(&semu_list, suptr, un_next);
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suptr->un_cnt = 0;
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suptr->un_proc = td->td_proc;
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return (suptr);
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}
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static int
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semu_try_free(struct sem_undo *suptr)
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{
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SEMUNDO_LOCKASSERT(MA_OWNED);
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if (suptr->un_cnt != 0)
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return (0);
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LIST_REMOVE(suptr, un_next);
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LIST_INSERT_HEAD(&semu_free_list, suptr, un_next);
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return (1);
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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(struct thread *td, struct sem_undo **supptr, int semid,
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int semseq, int semnum, int adjval)
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{
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struct proc *p = td->td_proc;
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struct sem_undo *suptr;
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struct undo *sunptr;
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int i;
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SEMUNDO_LOCKASSERT(MA_OWNED);
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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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LIST_FOREACH(suptr, &semu_list, 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(td);
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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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adjval += sunptr->un_adjval;
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if (adjval > seminfo.semaem || adjval < -seminfo.semaem)
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return (ERANGE);
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}
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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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if (suptr->un_cnt == 0)
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semu_try_free(suptr);
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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 (adjval > seminfo.semaem || adjval < -seminfo.semaem)
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return (ERANGE);
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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;
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sunptr->un_num = semnum;
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sunptr->un_seq = semseq;
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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(int semid, int semnum)
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{
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struct sem_undo *suptr, *suptr1;
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struct undo *sunptr;
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int i;
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SEMUNDO_LOCKASSERT(MA_OWNED);
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LIST_FOREACH_SAFE(suptr, &semu_list, un_next, suptr1) {
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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)
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continue;
|
|
if (semnum == -1 || sunptr->un_num == semnum) {
|
|
suptr->un_cnt--;
|
|
if (i < suptr->un_cnt) {
|
|
suptr->un_ent[i] =
|
|
suptr->un_ent[suptr->un_cnt];
|
|
continue;
|
|
}
|
|
semu_try_free(suptr);
|
|
}
|
|
if (semnum != -1)
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
static int
|
|
semvalid(int semid, struct semid_kernel *semakptr)
|
|
{
|
|
|
|
return ((semakptr->u.sem_perm.mode & SEM_ALLOC) == 0 ||
|
|
semakptr->u.sem_perm.seq != IPCID_TO_SEQ(semid) ? EINVAL : 0);
|
|
}
|
|
|
|
/*
|
|
* Note that the user-mode half of this passes a union, not a pointer.
|
|
*/
|
|
#ifndef _SYS_SYSPROTO_H_
|
|
struct __semctl_args {
|
|
int semid;
|
|
int semnum;
|
|
int cmd;
|
|
union semun *arg;
|
|
};
|
|
#endif
|
|
int
|
|
__semctl(struct thread *td, struct __semctl_args *uap)
|
|
{
|
|
struct semid_ds dsbuf;
|
|
union semun arg, semun;
|
|
register_t rval;
|
|
int error;
|
|
|
|
switch (uap->cmd) {
|
|
case SEM_STAT:
|
|
case IPC_SET:
|
|
case IPC_STAT:
|
|
case GETALL:
|
|
case SETVAL:
|
|
case SETALL:
|
|
error = copyin(uap->arg, &arg, sizeof(arg));
|
|
if (error)
|
|
return (error);
|
|
break;
|
|
}
|
|
|
|
switch (uap->cmd) {
|
|
case SEM_STAT:
|
|
case IPC_STAT:
|
|
semun.buf = &dsbuf;
|
|
break;
|
|
case IPC_SET:
|
|
error = copyin(arg.buf, &dsbuf, sizeof(dsbuf));
|
|
if (error)
|
|
return (error);
|
|
semun.buf = &dsbuf;
|
|
break;
|
|
case GETALL:
|
|
case SETALL:
|
|
semun.array = arg.array;
|
|
break;
|
|
case SETVAL:
|
|
semun.val = arg.val;
|
|
break;
|
|
}
|
|
|
|
error = kern_semctl(td, uap->semid, uap->semnum, uap->cmd, &semun,
|
|
&rval);
|
|
if (error)
|
|
return (error);
|
|
|
|
switch (uap->cmd) {
|
|
case SEM_STAT:
|
|
case IPC_STAT:
|
|
error = copyout(&dsbuf, arg.buf, sizeof(dsbuf));
|
|
break;
|
|
}
|
|
|
|
if (error == 0)
|
|
td->td_retval[0] = rval;
|
|
return (error);
|
|
}
|
|
|
|
int
|
|
kern_semctl(struct thread *td, int semid, int semnum, int cmd,
|
|
union semun *arg, register_t *rval)
|
|
{
|
|
u_short *array;
|
|
struct ucred *cred = td->td_ucred;
|
|
int i, error;
|
|
struct semid_ds *sbuf;
|
|
struct semid_kernel *semakptr;
|
|
struct mtx *sema_mtxp;
|
|
u_short usval, count;
|
|
int semidx;
|
|
|
|
DPRINTF(("call to semctl(%d, %d, %d, 0x%p)\n",
|
|
semid, semnum, cmd, arg));
|
|
if (!jail_sysvipc_allowed && jailed(td->td_ucred))
|
|
return (ENOSYS);
|
|
|
|
array = NULL;
|
|
|
|
switch(cmd) {
|
|
case SEM_STAT:
|
|
/*
|
|
* For this command we assume semid is an array index
|
|
* rather than an IPC id.
|
|
*/
|
|
if (semid < 0 || semid >= seminfo.semmni)
|
|
return (EINVAL);
|
|
semakptr = &sema[semid];
|
|
sema_mtxp = &sema_mtx[semid];
|
|
mtx_lock(sema_mtxp);
|
|
if ((semakptr->u.sem_perm.mode & SEM_ALLOC) == 0) {
|
|
error = EINVAL;
|
|
goto done2;
|
|
}
|
|
if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_R)))
|
|
goto done2;
|
|
#ifdef MAC
|
|
error = mac_sysvsem_check_semctl(cred, semakptr, cmd);
|
|
if (error != 0)
|
|
goto done2;
|
|
#endif
|
|
bcopy(&semakptr->u, arg->buf, sizeof(struct semid_ds));
|
|
*rval = IXSEQ_TO_IPCID(semid, semakptr->u.sem_perm);
|
|
mtx_unlock(sema_mtxp);
|
|
return (0);
|
|
}
|
|
|
|
semidx = IPCID_TO_IX(semid);
|
|
if (semidx < 0 || semidx >= seminfo.semmni)
|
|
return (EINVAL);
|
|
|
|
semakptr = &sema[semidx];
|
|
sema_mtxp = &sema_mtx[semidx];
|
|
if (cmd == IPC_RMID)
|
|
mtx_lock(&sem_mtx);
|
|
mtx_lock(sema_mtxp);
|
|
#ifdef MAC
|
|
error = mac_sysvsem_check_semctl(cred, semakptr, cmd);
|
|
if (error != 0)
|
|
goto done2;
|
|
#endif
|
|
|
|
error = 0;
|
|
*rval = 0;
|
|
|
|
switch (cmd) {
|
|
case IPC_RMID:
|
|
if ((error = semvalid(semid, semakptr)) != 0)
|
|
goto done2;
|
|
if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_M)))
|
|
goto done2;
|
|
semakptr->u.sem_perm.cuid = cred->cr_uid;
|
|
semakptr->u.sem_perm.uid = cred->cr_uid;
|
|
semakptr->u.sem_perm.mode = 0;
|
|
SEMUNDO_LOCK();
|
|
semundo_clear(semidx, -1);
|
|
SEMUNDO_UNLOCK();
|
|
#ifdef MAC
|
|
mac_sysvsem_cleanup(semakptr);
|
|
#endif
|
|
wakeup(semakptr);
|
|
for (i = 0; i < seminfo.semmni; i++) {
|
|
if ((sema[i].u.sem_perm.mode & SEM_ALLOC) &&
|
|
sema[i].u.sem_base > semakptr->u.sem_base)
|
|
mtx_lock_flags(&sema_mtx[i], LOP_DUPOK);
|
|
}
|
|
for (i = semakptr->u.sem_base - sem; i < semtot; i++)
|
|
sem[i] = sem[i + semakptr->u.sem_nsems];
|
|
for (i = 0; i < seminfo.semmni; i++) {
|
|
if ((sema[i].u.sem_perm.mode & SEM_ALLOC) &&
|
|
sema[i].u.sem_base > semakptr->u.sem_base) {
|
|
sema[i].u.sem_base -= semakptr->u.sem_nsems;
|
|
mtx_unlock(&sema_mtx[i]);
|
|
}
|
|
}
|
|
semtot -= semakptr->u.sem_nsems;
|
|
break;
|
|
|
|
case IPC_SET:
|
|
if ((error = semvalid(semid, semakptr)) != 0)
|
|
goto done2;
|
|
if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_M)))
|
|
goto done2;
|
|
sbuf = arg->buf;
|
|
semakptr->u.sem_perm.uid = sbuf->sem_perm.uid;
|
|
semakptr->u.sem_perm.gid = sbuf->sem_perm.gid;
|
|
semakptr->u.sem_perm.mode = (semakptr->u.sem_perm.mode &
|
|
~0777) | (sbuf->sem_perm.mode & 0777);
|
|
semakptr->u.sem_ctime = time_second;
|
|
break;
|
|
|
|
case IPC_STAT:
|
|
if ((error = semvalid(semid, semakptr)) != 0)
|
|
goto done2;
|
|
if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_R)))
|
|
goto done2;
|
|
bcopy(&semakptr->u, arg->buf, sizeof(struct semid_ds));
|
|
break;
|
|
|
|
case GETNCNT:
|
|
if ((error = semvalid(semid, semakptr)) != 0)
|
|
goto done2;
|
|
if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_R)))
|
|
goto done2;
|
|
if (semnum < 0 || semnum >= semakptr->u.sem_nsems) {
|
|
error = EINVAL;
|
|
goto done2;
|
|
}
|
|
*rval = semakptr->u.sem_base[semnum].semncnt;
|
|
break;
|
|
|
|
case GETPID:
|
|
if ((error = semvalid(semid, semakptr)) != 0)
|
|
goto done2;
|
|
if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_R)))
|
|
goto done2;
|
|
if (semnum < 0 || semnum >= semakptr->u.sem_nsems) {
|
|
error = EINVAL;
|
|
goto done2;
|
|
}
|
|
*rval = semakptr->u.sem_base[semnum].sempid;
|
|
break;
|
|
|
|
case GETVAL:
|
|
if ((error = semvalid(semid, semakptr)) != 0)
|
|
goto done2;
|
|
if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_R)))
|
|
goto done2;
|
|
if (semnum < 0 || semnum >= semakptr->u.sem_nsems) {
|
|
error = EINVAL;
|
|
goto done2;
|
|
}
|
|
*rval = semakptr->u.sem_base[semnum].semval;
|
|
break;
|
|
|
|
case GETALL:
|
|
/*
|
|
* Unfortunately, callers of this function don't know
|
|
* in advance how many semaphores are in this set.
|
|
* While we could just allocate the maximum size array
|
|
* and pass the actual size back to the caller, that
|
|
* won't work for SETALL since we can't copyin() more
|
|
* data than the user specified as we may return a
|
|
* spurious EFAULT.
|
|
*
|
|
* Note that the number of semaphores in a set is
|
|
* fixed for the life of that set. The only way that
|
|
* the 'count' could change while are blocked in
|
|
* malloc() is if this semaphore set were destroyed
|
|
* and a new one created with the same index.
|
|
* However, semvalid() will catch that due to the
|
|
* sequence number unless exactly 0x8000 (or a
|
|
* multiple thereof) semaphore sets for the same index
|
|
* are created and destroyed while we are in malloc!
|
|
*
|
|
*/
|
|
count = semakptr->u.sem_nsems;
|
|
mtx_unlock(sema_mtxp);
|
|
array = malloc(sizeof(*array) * count, M_TEMP, M_WAITOK);
|
|
mtx_lock(sema_mtxp);
|
|
if ((error = semvalid(semid, semakptr)) != 0)
|
|
goto done2;
|
|
KASSERT(count == semakptr->u.sem_nsems, ("nsems changed"));
|
|
if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_R)))
|
|
goto done2;
|
|
for (i = 0; i < semakptr->u.sem_nsems; i++)
|
|
array[i] = semakptr->u.sem_base[i].semval;
|
|
mtx_unlock(sema_mtxp);
|
|
error = copyout(array, arg->array, count * sizeof(*array));
|
|
mtx_lock(sema_mtxp);
|
|
break;
|
|
|
|
case GETZCNT:
|
|
if ((error = semvalid(semid, semakptr)) != 0)
|
|
goto done2;
|
|
if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_R)))
|
|
goto done2;
|
|
if (semnum < 0 || semnum >= semakptr->u.sem_nsems) {
|
|
error = EINVAL;
|
|
goto done2;
|
|
}
|
|
*rval = semakptr->u.sem_base[semnum].semzcnt;
|
|
break;
|
|
|
|
case SETVAL:
|
|
if ((error = semvalid(semid, semakptr)) != 0)
|
|
goto done2;
|
|
if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_W)))
|
|
goto done2;
|
|
if (semnum < 0 || semnum >= semakptr->u.sem_nsems) {
|
|
error = EINVAL;
|
|
goto done2;
|
|
}
|
|
if (arg->val < 0 || arg->val > seminfo.semvmx) {
|
|
error = ERANGE;
|
|
goto done2;
|
|
}
|
|
semakptr->u.sem_base[semnum].semval = arg->val;
|
|
SEMUNDO_LOCK();
|
|
semundo_clear(semidx, semnum);
|
|
SEMUNDO_UNLOCK();
|
|
wakeup(semakptr);
|
|
break;
|
|
|
|
case SETALL:
|
|
/*
|
|
* See comment on GETALL for why 'count' shouldn't change
|
|
* and why we require a userland buffer.
|
|
*/
|
|
count = semakptr->u.sem_nsems;
|
|
mtx_unlock(sema_mtxp);
|
|
array = malloc(sizeof(*array) * count, M_TEMP, M_WAITOK);
|
|
error = copyin(arg->array, array, count * sizeof(*array));
|
|
mtx_lock(sema_mtxp);
|
|
if (error)
|
|
break;
|
|
if ((error = semvalid(semid, semakptr)) != 0)
|
|
goto done2;
|
|
KASSERT(count == semakptr->u.sem_nsems, ("nsems changed"));
|
|
if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_W)))
|
|
goto done2;
|
|
for (i = 0; i < semakptr->u.sem_nsems; i++) {
|
|
usval = array[i];
|
|
if (usval > seminfo.semvmx) {
|
|
error = ERANGE;
|
|
break;
|
|
}
|
|
semakptr->u.sem_base[i].semval = usval;
|
|
}
|
|
SEMUNDO_LOCK();
|
|
semundo_clear(semidx, -1);
|
|
SEMUNDO_UNLOCK();
|
|
wakeup(semakptr);
|
|
break;
|
|
|
|
default:
|
|
error = EINVAL;
|
|
break;
|
|
}
|
|
|
|
done2:
|
|
mtx_unlock(sema_mtxp);
|
|
if (cmd == IPC_RMID)
|
|
mtx_unlock(&sem_mtx);
|
|
if (array != NULL)
|
|
free(array, M_TEMP);
|
|
return(error);
|
|
}
|
|
|
|
#ifndef _SYS_SYSPROTO_H_
|
|
struct semget_args {
|
|
key_t key;
|
|
int nsems;
|
|
int semflg;
|
|
};
|
|
#endif
|
|
int
|
|
semget(struct thread *td, struct semget_args *uap)
|
|
{
|
|
int semid, error = 0;
|
|
int key = uap->key;
|
|
int nsems = uap->nsems;
|
|
int semflg = uap->semflg;
|
|
struct ucred *cred = td->td_ucred;
|
|
|
|
DPRINTF(("semget(0x%x, %d, 0%o)\n", key, nsems, semflg));
|
|
if (!jail_sysvipc_allowed && jailed(td->td_ucred))
|
|
return (ENOSYS);
|
|
|
|
mtx_lock(&sem_mtx);
|
|
if (key != IPC_PRIVATE) {
|
|
for (semid = 0; semid < seminfo.semmni; semid++) {
|
|
if ((sema[semid].u.sem_perm.mode & SEM_ALLOC) &&
|
|
sema[semid].u.sem_perm.key == key)
|
|
break;
|
|
}
|
|
if (semid < seminfo.semmni) {
|
|
DPRINTF(("found public key\n"));
|
|
if ((error = ipcperm(td, &sema[semid].u.sem_perm,
|
|
semflg & 0700))) {
|
|
goto done2;
|
|
}
|
|
if (nsems > 0 && sema[semid].u.sem_nsems < nsems) {
|
|
DPRINTF(("too small\n"));
|
|
error = EINVAL;
|
|
goto done2;
|
|
}
|
|
if ((semflg & IPC_CREAT) && (semflg & IPC_EXCL)) {
|
|
DPRINTF(("not exclusive\n"));
|
|
error = EEXIST;
|
|
goto done2;
|
|
}
|
|
#ifdef MAC
|
|
error = mac_sysvsem_check_semget(cred, &sema[semid]);
|
|
if (error != 0)
|
|
goto done2;
|
|
#endif
|
|
goto found;
|
|
}
|
|
}
|
|
|
|
DPRINTF(("need to allocate the semid_kernel\n"));
|
|
if (key == IPC_PRIVATE || (semflg & IPC_CREAT)) {
|
|
if (nsems <= 0 || nsems > seminfo.semmsl) {
|
|
DPRINTF(("nsems out of range (0<%d<=%d)\n", nsems,
|
|
seminfo.semmsl));
|
|
error = EINVAL;
|
|
goto done2;
|
|
}
|
|
if (nsems > seminfo.semmns - semtot) {
|
|
DPRINTF((
|
|
"not enough semaphores left (need %d, got %d)\n",
|
|
nsems, seminfo.semmns - semtot));
|
|
error = ENOSPC;
|
|
goto done2;
|
|
}
|
|
for (semid = 0; semid < seminfo.semmni; semid++) {
|
|
if ((sema[semid].u.sem_perm.mode & SEM_ALLOC) == 0)
|
|
break;
|
|
}
|
|
if (semid == seminfo.semmni) {
|
|
DPRINTF(("no more semid_kernel's available\n"));
|
|
error = ENOSPC;
|
|
goto done2;
|
|
}
|
|
DPRINTF(("semid %d is available\n", semid));
|
|
mtx_lock(&sema_mtx[semid]);
|
|
KASSERT((sema[semid].u.sem_perm.mode & SEM_ALLOC) == 0,
|
|
("Lost semaphore %d", semid));
|
|
sema[semid].u.sem_perm.key = key;
|
|
sema[semid].u.sem_perm.cuid = cred->cr_uid;
|
|
sema[semid].u.sem_perm.uid = cred->cr_uid;
|
|
sema[semid].u.sem_perm.cgid = cred->cr_gid;
|
|
sema[semid].u.sem_perm.gid = cred->cr_gid;
|
|
sema[semid].u.sem_perm.mode = (semflg & 0777) | SEM_ALLOC;
|
|
sema[semid].u.sem_perm.seq =
|
|
(sema[semid].u.sem_perm.seq + 1) & 0x7fff;
|
|
sema[semid].u.sem_nsems = nsems;
|
|
sema[semid].u.sem_otime = 0;
|
|
sema[semid].u.sem_ctime = time_second;
|
|
sema[semid].u.sem_base = &sem[semtot];
|
|
semtot += nsems;
|
|
bzero(sema[semid].u.sem_base,
|
|
sizeof(sema[semid].u.sem_base[0])*nsems);
|
|
#ifdef MAC
|
|
mac_sysvsem_create(cred, &sema[semid]);
|
|
#endif
|
|
mtx_unlock(&sema_mtx[semid]);
|
|
DPRINTF(("sembase = %p, next = %p\n",
|
|
sema[semid].u.sem_base, &sem[semtot]));
|
|
} else {
|
|
DPRINTF(("didn't find it and wasn't asked to create it\n"));
|
|
error = ENOENT;
|
|
goto done2;
|
|
}
|
|
|
|
found:
|
|
td->td_retval[0] = IXSEQ_TO_IPCID(semid, sema[semid].u.sem_perm);
|
|
done2:
|
|
mtx_unlock(&sem_mtx);
|
|
return (error);
|
|
}
|
|
|
|
#ifndef _SYS_SYSPROTO_H_
|
|
struct semop_args {
|
|
int semid;
|
|
struct sembuf *sops;
|
|
size_t nsops;
|
|
};
|
|
#endif
|
|
int
|
|
semop(struct thread *td, struct semop_args *uap)
|
|
{
|
|
#define SMALL_SOPS 8
|
|
struct sembuf small_sops[SMALL_SOPS];
|
|
int semid = uap->semid;
|
|
size_t nsops = uap->nsops;
|
|
struct sembuf *sops;
|
|
struct semid_kernel *semakptr;
|
|
struct sembuf *sopptr = 0;
|
|
struct sem *semptr = 0;
|
|
struct sem_undo *suptr;
|
|
struct mtx *sema_mtxp;
|
|
size_t i, j, k;
|
|
int error;
|
|
int do_wakeup, do_undos;
|
|
unsigned short seq;
|
|
|
|
#ifdef SEM_DEBUG
|
|
sops = NULL;
|
|
#endif
|
|
DPRINTF(("call to semop(%d, %p, %u)\n", semid, sops, nsops));
|
|
|
|
if (!jail_sysvipc_allowed && jailed(td->td_ucred))
|
|
return (ENOSYS);
|
|
|
|
semid = IPCID_TO_IX(semid); /* Convert back to zero origin */
|
|
|
|
if (semid < 0 || semid >= seminfo.semmni)
|
|
return (EINVAL);
|
|
|
|
/* Allocate memory for sem_ops */
|
|
if (nsops <= SMALL_SOPS)
|
|
sops = small_sops;
|
|
else if (nsops <= seminfo.semopm)
|
|
sops = malloc(nsops * sizeof(*sops), M_TEMP, M_WAITOK);
|
|
else {
|
|
DPRINTF(("too many sops (max=%d, nsops=%d)\n", seminfo.semopm,
|
|
nsops));
|
|
return (E2BIG);
|
|
}
|
|
if ((error = copyin(uap->sops, sops, nsops * sizeof(sops[0]))) != 0) {
|
|
DPRINTF(("error = %d from copyin(%p, %p, %d)\n", error,
|
|
uap->sops, sops, nsops * sizeof(sops[0])));
|
|
if (sops != small_sops)
|
|
free(sops, M_SEM);
|
|
return (error);
|
|
}
|
|
|
|
semakptr = &sema[semid];
|
|
sema_mtxp = &sema_mtx[semid];
|
|
mtx_lock(sema_mtxp);
|
|
if ((semakptr->u.sem_perm.mode & SEM_ALLOC) == 0) {
|
|
error = EINVAL;
|
|
goto done2;
|
|
}
|
|
seq = semakptr->u.sem_perm.seq;
|
|
if (seq != IPCID_TO_SEQ(uap->semid)) {
|
|
error = EINVAL;
|
|
goto done2;
|
|
}
|
|
/*
|
|
* Initial pass thru sops to see what permissions are needed.
|
|
* Also perform any checks that don't need repeating on each
|
|
* attempt to satisfy the request vector.
|
|
*/
|
|
j = 0; /* permission needed */
|
|
do_undos = 0;
|
|
for (i = 0; i < nsops; i++) {
|
|
sopptr = &sops[i];
|
|
if (sopptr->sem_num >= semakptr->u.sem_nsems) {
|
|
error = EFBIG;
|
|
goto done2;
|
|
}
|
|
if (sopptr->sem_flg & SEM_UNDO && sopptr->sem_op != 0)
|
|
do_undos = 1;
|
|
j |= (sopptr->sem_op == 0) ? SEM_R : SEM_A;
|
|
}
|
|
|
|
if ((error = ipcperm(td, &semakptr->u.sem_perm, j))) {
|
|
DPRINTF(("error = %d from ipaccess\n", error));
|
|
goto done2;
|
|
}
|
|
#ifdef MAC
|
|
error = mac_sysvsem_check_semop(td->td_ucred, semakptr, j);
|
|
if (error != 0)
|
|
goto done2;
|
|
#endif
|
|
|
|
/*
|
|
* 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).
|
|
*/
|
|
for (;;) {
|
|
do_wakeup = 0;
|
|
error = 0; /* error return if necessary */
|
|
|
|
for (i = 0; i < nsops; i++) {
|
|
sopptr = &sops[i];
|
|
semptr = &semakptr->u.sem_base[sopptr->sem_num];
|
|
|
|
DPRINTF((
|
|
"semop: semakptr=%p, sem_base=%p, "
|
|
"semptr=%p, sem[%d]=%d : op=%d, flag=%s\n",
|
|
semakptr, semakptr->u.sem_base, semptr,
|
|
sopptr->sem_num, semptr->semval, sopptr->sem_op,
|
|
(sopptr->sem_flg & IPC_NOWAIT) ?
|
|
"nowait" : "wait"));
|
|
|
|
if (sopptr->sem_op < 0) {
|
|
if (semptr->semval + sopptr->sem_op < 0) {
|
|
DPRINTF(("semop: can't do it now\n"));
|
|
break;
|
|
} else {
|
|
semptr->semval += sopptr->sem_op;
|
|
if (semptr->semval == 0 &&
|
|
semptr->semzcnt > 0)
|
|
do_wakeup = 1;
|
|
}
|
|
} else if (sopptr->sem_op == 0) {
|
|
if (semptr->semval != 0) {
|
|
DPRINTF(("semop: not zero now\n"));
|
|
break;
|
|
}
|
|
} else if (semptr->semval + sopptr->sem_op >
|
|
seminfo.semvmx) {
|
|
error = ERANGE;
|
|
break;
|
|
} else {
|
|
if (semptr->semncnt > 0)
|
|
do_wakeup = 1;
|
|
semptr->semval += sopptr->sem_op;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Did we get through the entire vector?
|
|
*/
|
|
if (i >= nsops)
|
|
goto done;
|
|
|
|
/*
|
|
* No ... rollback anything that we've already done
|
|
*/
|
|
DPRINTF(("semop: rollback 0 through %d\n", i-1));
|
|
for (j = 0; j < i; j++)
|
|
semakptr->u.sem_base[sops[j].sem_num].semval -=
|
|
sops[j].sem_op;
|
|
|
|
/* If we detected an error, return it */
|
|
if (error != 0)
|
|
goto done2;
|
|
|
|
/*
|
|
* 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++;
|
|
|
|
DPRINTF(("semop: good night!\n"));
|
|
error = msleep(semakptr, sema_mtxp, (PZERO - 4) | PCATCH,
|
|
"semwait", 0);
|
|
DPRINTF(("semop: good morning (error=%d)!\n", error));
|
|
/* return code is checked below, after sem[nz]cnt-- */
|
|
|
|
/*
|
|
* Make sure that the semaphore still exists
|
|
*/
|
|
seq = semakptr->u.sem_perm.seq;
|
|
if ((semakptr->u.sem_perm.mode & SEM_ALLOC) == 0 ||
|
|
seq != IPCID_TO_SEQ(uap->semid)) {
|
|
error = EIDRM;
|
|
goto done2;
|
|
}
|
|
|
|
/*
|
|
* Renew the semaphore's pointer after wakeup since
|
|
* during msleep sem_base may have been modified and semptr
|
|
* is not valid any more
|
|
*/
|
|
semptr = &semakptr->u.sem_base[sopptr->sem_num];
|
|
|
|
/*
|
|
* The semaphore is still alive. Readjust the count of
|
|
* waiting processes.
|
|
*/
|
|
if (sopptr->sem_op == 0)
|
|
semptr->semzcnt--;
|
|
else
|
|
semptr->semncnt--;
|
|
|
|
/*
|
|
* Is it really morning, or was our sleep interrupted?
|
|
* (Delayed check of msleep() return code because we
|
|
* need to decrement sem[nz]cnt either way.)
|
|
*/
|
|
if (error != 0) {
|
|
error = EINTR;
|
|
goto done2;
|
|
}
|
|
DPRINTF(("semop: good morning!\n"));
|
|
}
|
|
|
|
done:
|
|
/*
|
|
* Process any SEM_UNDO requests.
|
|
*/
|
|
if (do_undos) {
|
|
SEMUNDO_LOCK();
|
|
suptr = NULL;
|
|
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(td, &suptr, semid, seq,
|
|
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 = 0; j < i; j++) {
|
|
k = i - j - 1;
|
|
if ((sops[k].sem_flg & SEM_UNDO) == 0)
|
|
continue;
|
|
adjval = sops[k].sem_op;
|
|
if (adjval == 0)
|
|
continue;
|
|
if (semundo_adjust(td, &suptr, semid, seq,
|
|
sops[k].sem_num, adjval) != 0)
|
|
panic("semop - can't undo undos");
|
|
}
|
|
|
|
for (j = 0; j < nsops; j++)
|
|
semakptr->u.sem_base[sops[j].sem_num].semval -=
|
|
sops[j].sem_op;
|
|
|
|
DPRINTF(("error = %d from semundo_adjust\n", error));
|
|
SEMUNDO_UNLOCK();
|
|
goto done2;
|
|
} /* loop through the sops */
|
|
SEMUNDO_UNLOCK();
|
|
} /* if (do_undos) */
|
|
|
|
/* We're definitely done - set the sempid's and time */
|
|
for (i = 0; i < nsops; i++) {
|
|
sopptr = &sops[i];
|
|
semptr = &semakptr->u.sem_base[sopptr->sem_num];
|
|
semptr->sempid = td->td_proc->p_pid;
|
|
}
|
|
semakptr->u.sem_otime = time_second;
|
|
|
|
/*
|
|
* Do a wakeup if any semaphore was up'd whilst something was
|
|
* sleeping on it.
|
|
*/
|
|
if (do_wakeup) {
|
|
DPRINTF(("semop: doing wakeup\n"));
|
|
wakeup(semakptr);
|
|
DPRINTF(("semop: back from wakeup\n"));
|
|
}
|
|
DPRINTF(("semop: done\n"));
|
|
td->td_retval[0] = 0;
|
|
done2:
|
|
mtx_unlock(sema_mtxp);
|
|
if (sops != small_sops)
|
|
free(sops, M_SEM);
|
|
return (error);
|
|
}
|
|
|
|
/*
|
|
* Go through the undo structures for this process and apply the adjustments to
|
|
* semaphores.
|
|
*/
|
|
static void
|
|
semexit_myhook(void *arg, struct proc *p)
|
|
{
|
|
struct sem_undo *suptr;
|
|
struct semid_kernel *semakptr;
|
|
struct mtx *sema_mtxp;
|
|
int semid, semnum, adjval, ix;
|
|
unsigned short seq;
|
|
|
|
/*
|
|
* Go through the chain of undo vectors looking for one
|
|
* associated with this process.
|
|
*/
|
|
SEMUNDO_LOCK();
|
|
LIST_FOREACH(suptr, &semu_list, un_next) {
|
|
if (suptr->un_proc == p)
|
|
break;
|
|
}
|
|
if (suptr == NULL) {
|
|
SEMUNDO_UNLOCK();
|
|
return;
|
|
}
|
|
LIST_REMOVE(suptr, un_next);
|
|
|
|
DPRINTF(("proc @%p has undo structure with %d entries\n", p,
|
|
suptr->un_cnt));
|
|
|
|
/*
|
|
* If there are any active undo elements then process them.
|
|
*/
|
|
if (suptr->un_cnt > 0) {
|
|
SEMUNDO_UNLOCK();
|
|
for (ix = 0; ix < suptr->un_cnt; ix++) {
|
|
semid = suptr->un_ent[ix].un_id;
|
|
semnum = suptr->un_ent[ix].un_num;
|
|
adjval = suptr->un_ent[ix].un_adjval;
|
|
seq = suptr->un_ent[ix].un_seq;
|
|
semakptr = &sema[semid];
|
|
sema_mtxp = &sema_mtx[semid];
|
|
|
|
mtx_lock(sema_mtxp);
|
|
if ((semakptr->u.sem_perm.mode & SEM_ALLOC) == 0 ||
|
|
(semakptr->u.sem_perm.seq != seq)) {
|
|
mtx_unlock(sema_mtxp);
|
|
continue;
|
|
}
|
|
if (semnum >= semakptr->u.sem_nsems)
|
|
panic("semexit - semnum out of range");
|
|
|
|
DPRINTF((
|
|
"semexit: %p 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,
|
|
semakptr->u.sem_base[semnum].semval));
|
|
|
|
if (adjval < 0 && semakptr->u.sem_base[semnum].semval <
|
|
-adjval)
|
|
semakptr->u.sem_base[semnum].semval = 0;
|
|
else
|
|
semakptr->u.sem_base[semnum].semval += adjval;
|
|
|
|
wakeup(semakptr);
|
|
DPRINTF(("semexit: back from wakeup\n"));
|
|
mtx_unlock(sema_mtxp);
|
|
}
|
|
SEMUNDO_LOCK();
|
|
}
|
|
|
|
/*
|
|
* Deallocate the undo vector.
|
|
*/
|
|
DPRINTF(("removing vector\n"));
|
|
suptr->un_proc = NULL;
|
|
suptr->un_cnt = 0;
|
|
LIST_INSERT_HEAD(&semu_free_list, suptr, un_next);
|
|
SEMUNDO_UNLOCK();
|
|
}
|
|
|
|
static int
|
|
sysctl_sema(SYSCTL_HANDLER_ARGS)
|
|
{
|
|
|
|
return (SYSCTL_OUT(req, sema,
|
|
sizeof(struct semid_kernel) * seminfo.semmni));
|
|
}
|