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/*
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* CDDL HEADER START
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*
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* The contents of this file are subject to the terms of the
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* Common Development and Distribution License (the "License").
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* You may not use this file except in compliance with the License.
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*
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* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
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* or http://www.opensolaris.org/os/licensing.
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* See the License for the specific language governing permissions
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* and limitations under the License.
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*
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* When distributing Covered Code, include this CDDL HEADER in each
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* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
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* If applicable, add the following below this CDDL HEADER, with the
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* fields enclosed by brackets "[]" replaced with your own identifying
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* information: Portions Copyright [yyyy] [name of copyright owner]
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*
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* CDDL HEADER END
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*/
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/*
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* Copyright 2008 Sun Microsystems, Inc. All rights reserved.
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* Use is subject to license terms.
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*/
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/* Copyright (c) 1988 AT&T */
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/* All Rights Reserved */
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#pragma ident "%Z%%M% %I% %E% SMI"
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#include "lint.h"
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#include <sys/types.h>
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#include <stdio.h>
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#include <signal.h>
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#include <fcntl.h>
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#include <unistd.h>
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#include <shadow.h>
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#include <errno.h>
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#include <thread.h>
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#include "mtlib.h"
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#define LOCKFILE "/etc/.pwd.lock"
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#define S_WAITTIME 15
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static struct flock flock = {
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0, /* l_type */
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0, /* l_whence */
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0, /* l_start */
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0, /* l_len */
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0, /* l_sysid */
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0 /* l_pid */
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};
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/*
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* lckpwdf() returns a 0 for a successful lock within W_WAITTIME
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* seconds and -1 otherwise. We stand on our head to make it MT-safe.
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*/
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static pid_t lck_pid = 0; /* process's pid at last lock */
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static thread_t lck_tid = 0; /* thread that holds the lock */
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static int fildes = -1;
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static mutex_t lck_lock = DEFAULTMUTEX;
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int
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lckpwdf(void)
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{
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int seconds = 0;
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lmutex_lock(&lck_lock);
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for (;;) {
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if (lck_pid != 0 && lck_pid != getpid()) {
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/* somebody forked */
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lck_pid = 0;
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lck_tid = 0;
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}
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if (lck_tid == 0) {
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if ((fildes = creat(LOCKFILE, 0600)) == -1)
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break;
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flock.l_type = F_WRLCK;
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if (fcntl(fildes, F_SETLK, &flock) != -1) {
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lck_pid = getpid();
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lck_tid = thr_self();
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lmutex_unlock(&lck_lock);
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return (0);
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}
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(void) close(fildes);
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fildes = -1;
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}
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if (seconds++ >= S_WAITTIME) {
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/*
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* For compatibility with the past, pretend
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* that we were interrupted by SIGALRM.
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*/
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errno = EINTR;
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break;
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}
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lmutex_unlock(&lck_lock);
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(void) sleep(1);
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lmutex_lock(&lck_lock);
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}
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lmutex_unlock(&lck_lock);
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return (-1);
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}
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/*
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* ulckpwdf() returns 0 for a successful unlock and -1 otherwise
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*/
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int
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ulckpwdf(void)
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{
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lmutex_lock(&lck_lock);
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if (lck_tid == thr_self() && fildes >= 0) {
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flock.l_type = F_UNLCK;
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(void) fcntl(fildes, F_SETLK, &flock);
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(void) close(fildes);
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fildes = -1;
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lck_pid = 0;
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lck_tid = 0;
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lmutex_unlock(&lck_lock);
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return (0);
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}
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lmutex_unlock(&lck_lock);
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return (-1);
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}
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