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sysv_ipc.c revision 1.2 
      1 /*
      2  * Copyright (c) 1988 University of Utah.
      3  * Copyright (c) 1990 The Regents of the University of California.
      4  * All rights reserved.
      5  *
      6  * This code is derived from software contributed to Berkeley by
      7  * the Systems Programming Group of the University of Utah Computer
      8  * Science Department. Originally from University of Wisconsin.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  * 3. All advertising materials mentioning features or use of this software
     19  *    must display the following acknowledgement:
     20  *	This product includes software developed by the University of
     21  *	California, Berkeley and its contributors.
     22  * 4. Neither the name of the University nor the names of its contributors
     23  *    may be used to endorse or promote products derived from this software
     24  *    without specific prior written permission.
     25  *
     26  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     27  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     29  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     30  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     31  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     32  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     34  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     35  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     36  * SUCH DAMAGE.
     37  *
     38  * from: Utah $Hdr: uipc_shm.c 1.9 89/08/14$
     39  *
     40  *	from: @(#)sysv_shm.c	7.15 (Berkeley) 5/13/91
     41  *	$Id: sysv_ipc.c,v 1.2 1993/12/18 04:21:46 mycroft Exp $
     42  */
     43 
     44 /*
     45  * IPC routines shared by some or all of the SYSV IPC system calls.
     46  */
     47 
     48 #ifndef SYSVIPC
     49 
     50 #ifdef SYSVSHM
     51 #define SYSVIPC
     52 #endif
     53 
     54 #ifdef SYSVSEM
     55 #define SYSVIPC
     56 #endif
     57 
     58 #ifdef SYSVMSG
     59 #define SYSVIPC
     60 #endif
     61 
     62 #endif
     63 
     64 #ifdef SYSVIPC
     65 
     66 #include <sys/param.h>
     67 #include <sys/systm.h>
     68 #include <sys/kernel.h>
     69 #include <sys/proc.h>
     70 #include <sys/ipc.h>
     71 #include <sys/shm.h>
     72 
     73 /*
     74  * Perform access checking.
     75  */
     76 
     77 ipcaccess(ipc, mode, cred)
     78 	register struct ipc_perm *ipc;
     79 	int mode;
     80 	register struct ucred *cred;
     81 {
     82 	register int m;
     83 
     84 	if (cred->cr_uid == 0)
     85 		return(0);
     86 	/*
     87 	 * Access check is based on only one of owner, group, public.
     88 	 * If not owner, then check group.
     89 	 * If not a member of the group, then check public access.
     90 	 */
     91 	mode &= 0700;
     92 	m = ipc->mode;
     93 	if (cred->cr_uid != ipc->uid && cred->cr_uid != ipc->cuid) {
     94 		m <<= 3;
     95 		if (!groupmember(ipc->gid, cred) &&
     96 		    !groupmember(ipc->cgid, cred))
     97 			m <<= 3;
     98 	}
     99 	if ((mode&m) == mode)
    100 		return (0);
    101 	return (EACCES);
    102 }
    103 #endif /* SYSVSHM */
    104