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sysv_ipc.c revision 1.12 
      1 /*	$NetBSD: sysv_ipc.c,v 1.12 1997/05/08 17:16:15 mycroft Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1995 Charles M. Hannum.  All rights reserved.
      5  *
      6  * Redistribution and use in source and binary forms, with or without
      7  * modification, are permitted provided that the following conditions
      8  * are met:
      9  * 1. Redistributions of source code must retain the above copyright
     10  *    notice, this list of conditions and the following disclaimer.
     11  * 2. Redistributions in binary form must reproduce the above copyright
     12  *    notice, this list of conditions and the following disclaimer in the
     13  *    documentation and/or other materials provided with the distribution.
     14  * 3. All advertising materials mentioning features or use of this software
     15  *    must display the following acknowledgement:
     16  *      This product includes software developed by Charles M. Hannum.
     17  * 4. The name of the author may not be used to endorse or promote products
     18  *    derived from this software without specific prior written permission.
     19  *
     20  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     21  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     22  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     23  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     24  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
     25  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     26  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     27  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     28  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
     29  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     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 #include <sys/mount.h>
     38 #include <sys/vnode.h>
     39 #include <sys/stat.h>
     40 
     41 /*
     42  * Check for ipc permission
     43  */
     44 
     45 int
     46 ipcperm(cred, perm, mode)
     47 	struct ucred *cred;
     48 	struct ipc_perm *perm;
     49 	int mode;
     50 {
     51 	mode_t mask;
     52 
     53 	if (cred->cr_uid == 0)
     54 		return (0);
     55 
     56 	if (mode == IPC_M) {
     57 		if (cred->cr_uid == perm->uid ||
     58 		    cred->cr_uid == perm->cuid)
     59 			return (0);
     60 		return (EPERM);
     61 	}
     62 
     63 	mask = 0;
     64 
     65 	if (cred->cr_uid == perm->uid ||
     66 	    cred->cr_uid == perm->cuid) {
     67 		if (mode & IPC_R)
     68 			mask |= S_IRUSR;
     69 		if (mode & IPC_W)
     70 			mask |= S_IWUSR;
     71 		return ((perm->mode & mask) == mask ? 0 : EACCES);
     72 	}
     73 
     74 	if (cred->cr_gid == perm->gid || groupmember(perm->gid, cred) ||
     75 	    cred->cr_gid == perm->cgid || groupmember(perm->cgid, cred)) {
     76 		if (mode & IPC_R)
     77 			mask |= S_IRGRP;
     78 		if (mode & IPC_W)
     79 			mask |= S_IWGRP;
     80 		return ((perm->mode & mask) == mask ? 0 : EACCES);
     81 	}
     82 
     83 	if (mode & IPC_R)
     84 		mask |= S_IROTH;
     85 	if (mode & IPC_W)
     86 		mask |= S_IWOTH;
     87 	return ((perm->mode & mask) == mask ? 0 : EACCES);
     88 }
     89