minor formatting and comment changes; removed some old #if 0'd code.

[unix-history] / sys / kern / sysv_ipc.c

/*
* Copyright (c) 1988 University of Utah.
* Copyright (c) 1990 The Regents of the University of California.
* All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* the Systems Programming Group of the University of Utah Computer
* Science Department. Originally from University of Wisconsin.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in the
*    documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
*    must display the following acknowledgement:
*      This product includes software developed by the University of
*      California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
*    may be used to endorse or promote products derived from this software
*    without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* from: Utah $Hdr: uipc_shm.c 1.9 89/08/14$
*
*      @(#)sysv_shm.c  7.15 (Berkeley) 5/13/91
*/

/*
* IPC routines shared by some or all of the SYSV IPC system calls.
*/

#ifndef SYSVIPC

#ifdef SYSVSHM
#define SYSVIPC
#endif

#ifdef SYSVSEM
#define SYSVIPC
#endif

#ifdef SYSVMSG
#define SYSVIPC
#endif

#endif

#ifdef SYSVIPC

#include "param.h"
#include "systm.h"
#include "kernel.h"
#include "proc.h"
#include "ipc.h"
#include "shm.h"

/*
* Perform access checking.
*/

int
ipcaccess(ipc, mode, cred)
       register struct ipc_perm *ipc;
       int mode;
       register struct ucred *cred;
{
       register int m;

       if (cred->cr_uid == 0)
               return(0);
       /*
        * Access check is based on only one of owner, group, public.
        * If not owner, then check group.
        * If not a member of the group, then check public access.
        */
       mode &= 0700;
       m = ipc->mode;
       if (cred->cr_uid != ipc->uid && cred->cr_uid != ipc->cuid) {
               m <<= 3;
               if (!groupmember(ipc->gid, cred) &&
                   !groupmember(ipc->cgid, cred))
                       m <<= 3;
       }
       if ((mode&m) == mode)
               return (0);
       return (EACCES);
}
#endif /* SYSVSHM */