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version 2.0

/*************************************************************************
 * (C) 2010 AITNET - Sofia/Bulgaria - <office@aitbg.com>
 *  by Michael Pounov <misho@aitbg.com>
 *
 * $Author: misho $
 * $Id: wdog.c,v 1.4 2014/02/05 15:44:06 misho Exp $
 *
 *************************************************************************
The ELWIX and AITNET software is distributed under the following
terms:

All of the documentation and software included in the ELWIX and AITNET
Releases is copyrighted by ELWIX - Sofia/Bulgaria <info@elwix.org>

Copyright 2004 - 2014
	by Michael Pounov <misho@elwix.org>.  All rights reserved.

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 Michael Pounov <misho@elwix.org>
ELWIX - Embedded LightWeight unIX and its contributors.
4. Neither the name of AITNET 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 AITNET 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.
*/
#include "global.h"


int Verbose, Kill, Log;
extern char compiled[], compiledby[], compilehost[];


static void
Usage()
{

	printf(	"WatchDog tool for risk process managment\n"
		"=== %s === %s@%s ===\n\n"
		"  Syntax: wdog [options] [exec_file]\n\n"
		"\t-v\t\tVerbose ...\n"
		"\t-c <dir>\tBefore execute chroot to dir [default=/]\n"
		"\t-u <user>\tBefore execute change user\n"
		"\t-P\t\tInfinit loop, bypass penalty timeout\n"
		"\t-S\t\tDisable send log events to syslog\n"
		"\n", compiled, compiledby, compilehost);
}

static void
sigHand(int sig)
{
	int stat;

	switch (sig) {
		case SIGTERM:
			Kill++;
			break;
		case SIGCHLD:
			while (waitpid(-1, &stat, WNOHANG) > 0);
			break;
	}
}

static void
logmsg(int prio, const char *fmt, ...)
{
	va_list lst;

	va_start(lst, fmt);
	if (!Log)
		vsyslog(prio, fmt, lst);
	else
		vprintf(fmt, lst);
	va_end(lst);
}


int
main(int argc, char **argv)
{
	char ch, bypass = 0, szChroot[MAXPATHLEN] = DEFAULT_CHROOT;
	int status = 0, ret = 1;
	struct sigaction sa;
	struct passwd *pass = NULL;
	u_int penalty = 1;
	uid_t uid = getuid();

	while ((ch = getopt(argc, argv, "vhSPc:u:")) != -1)
		switch (ch) {
			case 'v':
				Verbose++;
				break;
			case 'P':
				bypass = 1;
				break;
			case 'S':
				Log = 1;
				break;
			case 'c':
				if (uid) {
					printf("Error:: can`t chroot, please run as root!\n");
					goto end;
				}
				if (access(optarg, R_OK)) {
					printf("Error:: can`t chroot to %s #%d - %s\n", optarg, 
							errno, strerror(errno));
					goto end;
				} else
					strlcpy(szChroot, optarg, MAXPATHLEN);
				status |= 1;
				break;
			case 'u':
				if (uid) {
					printf("Error:: can`t setuid, please run as root!\n");
					goto end;
				}
				pass = getpwnam(optarg);
				if (!pass) {
					printf("Error:: can`t find user %s\n", optarg);
					goto end;
				} else
					uid = pass->pw_uid;
				endpwent();
				status |= 2;
				break;
			case 'h':
			default:
				Usage();
				goto end;
		}
	argc -= optind;
	argv += optind;
	if (!argc || !argv || !*argv) {
		Usage();
		goto end;
	}

	if (!Log)
		openlog("wdog", LOG_PID, LOG_USER);

	VERB(2) logmsg(LOG_NOTICE, "Info:: Chroot=%s Run=%s\n", szChroot, *argv);

	memset(&sa, 0, sizeof sa);
	sa.sa_handler = sigHand;
	sigemptyset(&sa.sa_mask);
	sigaction(SIGTERM, &sa, NULL);
	sigaction(SIGCHLD, &sa, NULL);
	sa.sa_handler = SIG_IGN;
	sigaction(SIGHUP, &sa, NULL);
	sigaction(SIGINT, &sa, NULL);
	sigaction(SIGQUIT, &sa, NULL);
	sigaction(SIGPIPE, &sa, NULL);
	sigaction(SIGTSTP, &sa, NULL);
	sigaction(SIGSTOP, &sa, NULL);
	VERB(5) logmsg(LOG_NOTICE, "Info:: Catched signals ...\n");

	if (status & 1 && (ret = chroot(szChroot)) == -1) {
		printf("Error:: error in chroot to %s #%d - %s\n", szChroot, errno, strerror(errno));
		ret = 3;
		goto end;
	} else
		VERB(1) logmsg(LOG_NOTICE, "Info:: chrooted to %s\n", szChroot);

	if (status & 2 && setuid(uid) == -1) {
		printf("Error:: error in setuid to %u #%d - %s\n", uid, errno, strerror(errno));
		ret = 4;
		goto end;
	} else
		VERB(1) logmsg(LOG_NOTICE, "Info:: setuid to %u\n", uid);

	status ^= status;
	while (!Kill && penalty) {
		switch ((ret = fork())) {
			case -1:
				logmsg(LOG_ERR, "Error:: error in fork #%d - %s\n", errno, strerror(errno));
				ret = 5;
				goto end;
			case 0:
				VERB(3) logmsg(LOG_NOTICE, "Info:: I`m child of shadows ...\n");
				if (execvp(*argv, argv) == -1) {
					logmsg(LOG_ERR, "Error:: error in exec %s #%d - %s\n", 
							*argv, errno, strerror(errno));
					ret = 6;
					goto end;
				}
				/* never reached !!! */
				break;
			default:
				wait(&status);
				kill(ret, SIGTERM);
				ret = status;
		}
		/* penalty timeout retry */
		usleep(penalty);
		if (!bypass) {
			penalty <<= 1;
			VERB(2) logmsg(LOG_NOTICE, "Info:: penalty timeout %u microseconds\n", penalty);
		}
	}
	if (!penalty)
		ret = 9;
end:
	if (!Log)
		closelog();
	return ret;
}