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sysv_ipc.c revision 1.4 
      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. The name of the author may not be used to endorse or promote products
     11  *    derived from this software without specific prior written permission
     12  *
     13  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     14  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     15  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     16  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     17  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
     18  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     19  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     20  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     21  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
     22  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     23  *
     24  */
     25 
     26 #include <sys/param.h>
     27 #include <sys/kernel.h>
     28 #include <sys/proc.h>
     29 #include <sys/ipc.h>
     30 #include <sys/systm.h>
     31 
     32 /*
     33  * Check for ipc permission
     34  */
     35 
     36 int
     37 ipcperm(uc, perm, mode)
     38 	struct ucred *uc;
     39 	struct ipc_perm *perm;
     40 	int mode;
     41 {
     42 	int i = 0;
     43 
     44 	if (uc->cr_uid == 0)
     45 		return(0);
     46 
     47 	/*
     48 	 * Does the user have permission?
     49 	 */
     50 	if (uc->cr_uid != perm->cuid && uc->cr_uid != perm->uid) {
     51 		i = 3;
     52 		/*
     53 		 * Does the group have permission?
     54 		 */
     55 		if (!groupmember(perm->gid, uc) && !groupmember(perm->cgid, uc))
     56 			i += 3;
     57 	}
     58 
     59 	if (((mode&0700) & (perm->mode << i)) != mode)
     60 		return(EACCES);
     61 }
     62