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version 2.0

/*************************************************************************
 * (C) 2009 AITNET - Sofia/Bulgaria - <office@aitbg.com>
 *  by Michael Pounov <misho@aitbg.com>
 *
 * $Author: misho $
 * $Id: cfexec.c,v 1.5 2014/02/05 15:44:05 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"


cfg_root_t cfg;
int Verbose, Timeout, kq;
ait_val_t User, Mount, Dev, Chroot;
char szSess[MAXPATHLEN], szConfig[MAXPATHLEN];
extern char compiled[], compiledby[], compilehost[];


static void
Usage()
{

	printf(	"CFExec is tool for managment R/W operation with CompactFlash\n"
		"=== %s === %s@%s ===\n\n"
		"  Syntax: cfexec [options] [exec_file]\n\n"
		"\t-v\t\tVerbose ...\n"
		"\t-c <dir>\tAfter execute chroot to dir [default=/]\n"
		"\t-u <user>\tAfter execute suid to user [default=root]\n"
		"\t-d <dev>\tOther device [default=/dev/ufs/elwix]\n"
		"\t-m <mnt>\tOther mount dir [default=/]\n"
		"\t-t <sec>\tTimeout for autolock mount dir after seconds [default=300]\n"
		"\n", compiled, compiledby, compilehost);
}

static int
update(int flags)
{
	struct ufs_args mnt;

	memset(&mnt, 0, sizeof mnt);
	mnt.fspec = AIT_GET_STR(&Dev);
#ifdef __NetBSD__
	if (mount("ufs", AIT_GET_STR(&Mount), flags, &mnt, sizeof mnt) == -1) {
#else
	if (mount("ufs", AIT_GET_STR(&Mount), flags, &mnt) == -1) {
#endif
		printf("Error:: can`t update mount %s #%d - %s\n", AIT_GET_STR(&Mount), 
				errno, strerror(errno));
		return -1;
	}

	VERB(5) printf("Info(5):: safe mount for device %s to %s operation (%s)\n", 
			AIT_GET_STR(&Dev), AIT_GET_STR(&Mount), (flags & MNT_RDONLY) ? "ro" : "rw");
	return 0;
}

static void
setuser()
{
	struct passwd *pw;

	pw = getpwnam(AIT_GET_LIKE(&User, char*));
	if (pw) {
		setuid(pw->pw_uid);
		setgid(pw->pw_gid);
		endpwent();

		VERB(5) printf("Info(5):: Suid to user %s.\n", AIT_GET_STR(&User));
	} else
		VERB(5) printf("Info(5):: Can`t suid to user %s !\n", AIT_GET_STR(&User));
}

static int
mkevent(struct kevent *chg, struct kevent *evt)
{
	int f;
	char szStr[STRSIZ];

	f = open(szSess, O_CREAT | O_WRONLY | O_TRUNC, 0644);
	if (f == -1) {
		printf("Error:: can`t lock session #%d - %s\n", errno, strerror(errno));
		return -1;
	} else {
		memset(szStr, 0, sizeof szStr);
		snprintf(szStr, sizeof szStr, "%d", getpid());
		write(f, szStr, strlen(szStr));
	}
	VERB(3) printf("Created lock file %s\n", szSess);

	kq = kqueue();
	if (kq == -1) {
		printf("Error:: can`t execute safe mount #%d - %s\n", errno, strerror(errno));
		close(f);
		unlink(szSess);
		return -1;
	} else {
		memset(chg, 0, sizeof(struct kevent));
		memset(evt, 0, sizeof(struct kevent));

		EV_SET(chg, f, EVFILT_VNODE, EV_ADD, NOTE_DELETE | NOTE_RENAME | NOTE_REVOKE, 
				0, NULL);
	}

	return f;
}

static void
cleanexit()
{
	AIT_FREE_VAL(&User);
	AIT_FREE_VAL(&Dev);
	AIT_FREE_VAL(&Mount);
	AIT_FREE_VAL(&Chroot);

	cfgUnloadConfig(&cfg);
}


int
main(int argc, char **argv)
{
	char ch;
	const char *err = NULL;
	struct kevent chg, evt;
	struct timespec ts;
	pid_t pid;
	int f, stat = 0;

	strlcpy(szConfig, DEFAULT_CONFIG, MAXPATHLEN);
	/* Load variables from config if exists */
	if (!cfgLoadConfig(szConfig, &cfg)) {
		cfg_loadAttribute(&cfg, "cfexec", "timeout", &User, DEFAULT_TIMEOUT);
#ifndef HAVE_STRTONUM
		Timeout = (int) strtol(szUser, NULL, 0);
#else
		Timeout = strtonum(AIT_GET_STR(&User), 0, 3600, &err);
#endif
		AIT_FREE_VAL(&User);
		if (!Timeout && err) {
			printf("Error:: in seconds for timeout %s - %s\n", optarg, err);
			cfgUnloadConfig(&cfg);
			return 1;
		}
		cfg_loadAttribute(&cfg, "cfexec", "suid", &User, DEFAULT_USER);
		cfg_loadAttribute(&cfg, "cfexec", "mount", &Mount, DEFAULT_MOUNT);
		cfg_loadAttribute(&cfg, "cfexec", "device", &Dev, DEFAULT_DEVICE);
		cfg_loadAttribute(&cfg, "cfexec", "chroot", &Chroot, DEFAULT_CHROOT);

		cfgUnloadConfig(&cfg);
	} else {
		Timeout = atoi(DEFAULT_TIMEOUT);
		AIT_SET_STR(&User, DEFAULT_USER);
		AIT_SET_STR(&Mount, DEFAULT_MOUNT);
		AIT_SET_STR(&Dev, DEFAULT_DEVICE);
		AIT_SET_STR(&Chroot, DEFAULT_CHROOT);
	}

	atexit(cleanexit);

	/* Load variables from arguments if exists */
	while ((ch = getopt(argc, argv, "hvu:c:d:m:t:")) != -1)
		switch (ch) {
			case 'v':
				Verbose++;
				break;
			case 'u':
				AIT_SET_STR(&User, optarg);
				break;
			case 'c':
				AIT_SET_STR(&Chroot, optarg);
				break;
			case 'd':
				AIT_SET_STR(&Dev, optarg);
				break;
			case 'm':
				AIT_SET_STR(&Mount, optarg);
				break;
			case 't':
#ifndef HAVE_STRTONUM
				Timeout = (int) strtol(optarg, NULL, 0);
#else
				Timeout = strtonum(optarg, 0, 3600, &err);
#endif
				if (!Timeout && err) {
					printf("Error:: in seconds for timeout %s - %s\n",
							optarg, err);
					return 1;
				}
				break;
			case 'h':
			default:
				Usage();
				return 1;
		}
	argc -= optind;
	argv += optind;

	memset(szSess, 0, MAXPATHLEN);
	snprintf(szSess, MAXPATHLEN, "%s%s-cfexec.LCK", DEFAULT_TMP, AIT_GET_STR(&Mount));

	VERB(3) printf("Info(3):: Chroot=%s SUID=%s Device=%s Mount=%s Timeout=%d Session=%s\n", 
			AIT_GET_STR(&Chroot), AIT_GET_STR(&User), AIT_GET_STR(&Dev), 
			AIT_GET_STR(&Mount), Timeout, szSess);

	if (!access(szSess, F_OK)) {
		printf("cfexec already running ...\n");
		return 127;
	}

	if (!argc) {
		switch (fork()) {
			case -1:
				printf("Error:: can`t execute safe mount #%d - %s\n", 
						errno, strerror(errno));
				return 3;
			case 0:
				VERB(5) printf("Info(5):: Go safe mount.\n");
				setsid();

				if (update(MNT_UPDATE) == -1)
					return 4;

				if ((f = mkevent(&chg, &evt)) == -1)
					return 5;

				if (Timeout) {
					memset(&ts, 0, sizeof ts);
					ts.tv_sec = Timeout;
				}
				switch (kevent(kq, &chg, 1, &evt, 1, !Timeout ? NULL : &ts)) {
					case -1:
						printf("Error:: can`t execute safe mount #%d - %s\n", 
								errno, strerror(errno));
						stat = 7;
						break;
					case 0:
						VERB(1) printf("Timeout reached - secure mount\n");
					default:
						VERB(1) printf("Lock file is deleted - secure mount\n");
						if (update(MNT_UPDATE | MNT_RDONLY) == -1)
							stat = 8;
				}

				close(kq);
				close(f);
				unlink(szSess);
				break;
		}
	} else {
		/*
		sigemptyset(&sig);
		sigaddset(&sig, SIGINT);
		sigaddset(&sig, SIGTSTP);
		sigprocmask(SIG_BLOCK, &sig, &oldsig);
		*/

		if (update(MNT_UPDATE) == -1)
			return 4;

		switch ((pid = vfork())) {
			case -1:
				printf("Error:: can`t execute safe mount #%d - %s\n", 
						errno, strerror(errno));
				return 5;
			case 0:
				VERB(5) printf("Go to running process %s\n", *argv);
				if (chroot(AIT_GET_STR(&Chroot)) == -1) {
					printf("Error:: can`t chroot to dir %s #%d - %s\n", 
							AIT_GET_STR(&Chroot), errno, strerror(errno));
				} else {
					if (strncmp(AIT_GET_STR(&User), "root", 5))
						setuser();

					/* chdir("/"); */
					execvp(*argv, argv);
				}
				exit(127);
				break;
			default:
				waitpid(pid, &stat, 0);
				VERB(3) printf("Return code: %d\n", stat);
				if (stat == 32512) 
					stat = 127;

				if (update(MNT_UPDATE | MNT_RDONLY) == -1)
					return 8;
		}
	}

	return stat;
}