usr/src/cmd/ypcmd/yppasswd/yplckpwdf.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License, Version 1.0 only
   6  * (the "License").  You may not use this file except in compliance
   7  * with the License.
   8  *
   9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
  10  * or http://www.opensolaris.org/os/licensing.
  11  * See the License for the specific language governing permissions
  12  * and limitations under the License.
  13  *
  14  * When distributing Covered Code, include this CDDL HEADER in each
  15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  16  * If applicable, add the following below this CDDL HEADER, with the
  17  * fields enclosed by brackets "[]" replaced with your own identifying
  18  * information: Portions Copyright [yyyy] [name of copyright owner]
  19  *
  20  * CDDL HEADER END
  21  */
  22 /*
  23  * Copyright (c) 1996-2001 by Sun Microsystems, Inc.
  24  * All rights reserved.
  25  */
  26
  27 /*      Copyright (c) 1988 AT&T */
  28 /*        All Rights Reserved   */
  29
  30
  31 #pragma ident   "%Z%%M% %I%     %E% SMI"
  32
  33 #include <stdio.h>
  34 #include <signal.h>
  35 #include <fcntl.h>
  36 #include <unistd.h> /* alarm() */
  37
  38 #define S_WAITTIME      15
  39
  40 static struct flock flock =     {
  41                         0,      /* l_type */
  42                         0,      /* l_whence */
  43                         0,      /* l_start */
  44                         0,      /* l_len */
  45                         0,      /* l_sysid */
  46                         0       /* l_pid */
  47                         };
  48
  49 /*
  50  *      yplckpwdf() returns a 0 for a successful lock within W_WAITTIME
  51  *      and -1 otherwise
  52  */
  53
  54 static int fildes = -1;
  55 extern char lockfile[];
  56
  57 /* ARGSUSED */
  58 static void
  59 almhdlr(int sig)
  60 {
  61 }
  62
  63 int
  64 yplckpwdf()
  65 {
  66         int retval;
  67         if ((fildes = creat(lockfile, 0600)) == -1)
  68                 return (-1);
  69
  70         flock.l_type = F_WRLCK;
  71         (void) sigset(SIGALRM, almhdlr);
  72         (void) alarm(S_WAITTIME);
  73         retval = fcntl(fildes, F_SETLKW, (int)&flock);
  74         (void) alarm(0);
  75         (void) sigset(SIGALRM, SIG_DFL);
  76         return (retval);
  77
  78 }
  79
  80 /*
  81  *      ypulckpwdf() returns 0 for a successful unlock and -1 otherwise
  82  */
  83 int
  84 ypulckpwdf()
  85 {
  86         if (fildes == -1)
  87                 return (-1);
  88
  89         flock.l_type = F_UNLCK;
  90         (void) fcntl(fildes, F_SETLK, (int)&flock);
  91         (void) close(fildes);
  92         fildes = -1;
  93         return (0);
  94
  95 }