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sysv_ipc.c revision 1.6 
      1 /*
      2  * Copyright (c) 1994 Herb Peyerl <hpeyerl (at) novatel.ca>
      3  * All rights reserved.
      4  *
      5  * Redistribution and use in source and binary forms, with or without
      6  * modification, are permitted provided that the following conditions
      7  * are met:
      8  * 1. Redistributions of source code must retain the above copyright
      9  *    notice, this list of conditions and the following disclaimer.
     10  * 2. Redistributions in binary form must reproduce the above copyright
     11  *    notice, this list of conditions and the following disclaimer in the
     12  *    documentation and/or other materials provided with the distribution.
     13  * 3. All advertising materials mentioning features or use of this software
     14  *    must display the following acknowledgement:
     15  *      This product includes software developed by Herb Peyerl.
     16  * 4. The name of Herb Peyerl may not be used to endorse or promote products
     17  *    derived from this software without specific prior written permission.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     20  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     21  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     22  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     23  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
     24  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     25  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     26  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     27  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
     28  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     29  *
     30  */
     31 
     32 #include <sys/param.h>
     33 #include <sys/kernel.h>
     34 #include <sys/proc.h>
     35 #include <sys/ipc.h>
     36 #include <sys/systm.h>
     37 
     38 /*
     39  * Check for ipc permission
     40  */
     41 
     42 int
     43 ipcperm(cred, perm, mode)
     44 	struct ucred *cred;
     45 	struct ipc_perm *perm;
     46 	int mode;
     47 {
     48 
     49 	if (cred->cr_uid == 0)
     50 		return (0);
     51 
     52 	/* Check for user match. */
     53 	if (cred->cr_uid != perm->cuid && cred->cr_uid != perm->uid) {
     54 		if (mode & IPC_M)
     55 			return (EPERM);
     56 		/* Check for group match. */
     57 		mode >>= 3;
     58 		if (!groupmember(perm->gid, cred) &&
     59 		    !groupmember(perm->cgid, cred))
     60 			/* Check for `other' match. */
     61 			mode >>= 3;
     62 	}
     63 
     64 	if (mode & IPC_M)
     65 		return (0);
     66 	return ((mode & perm->mode) == mode ? 0 : EACCES);
     67 }
     68