/*

 * utmpwatcher.c

 *

 * Copyright (C) 2006 Red Hat 

 * see file 'COPYING' for use and warranty information

 *

 * This program is free software; you can redistribute it and/or

 * modify it under the terms of the GNU General Public License as

 * published by the Free Software Foundation; either version 2 of

 * the License, or (at your option) any later version.

 * 

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

.* 

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA     

 * 02111-1307  USA

 *

 * Authors:  

 *   Dan Walsh <dwalsh@redhat.com>

 *

 *

*/

#define _GNU_SOURCE

#include <sys/inotify.h>

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <sys/types.h>

#include <sys/stat.h>

#include <syslog.h>

#include <limits.h>

#include <utmp.h>

#include <sys/types.h>

#include <pwd.h>

#include "restorecond.h"

#include "utmpwatcher.h"

#include "stringslist.h"

static struct stringsList *utmp_ptr = NULL;

static int utmp_wd = -1;

unsigned int utmpwatcher_handle(int inotify_fd, int wd)

{

	int changed = 0;

	struct utmp u;

	const char *utmp_path = "/var/run/utmp";

	struct stringsList *prev_utmp_ptr = utmp_ptr;

	if (wd != utmp_wd)

		return -1;

	utmp_ptr = NULL;

	FILE *cfg = fopen(utmp_path, "r");

	if (!cfg)

		exitApp("Error reading utmp file.");

	while (fread(&u, sizeof(struct utmp), 1, cfg) > 0) {

		if (u.ut_type == USER_PROCESS)

			strings_list_add(&utmp_ptr, u.ut_user);

	}

	fclose(cfg);

	if (utmp_wd >= 0)

		inotify_rm_watch(inotify_fd, utmp_wd);

	utmp_wd =

	    inotify_add_watch(inotify_fd, utmp_path, IN_MOVED_FROM | IN_MODIFY);

	if (utmp_wd == -1)

		exitApp("Error watching utmp file.");

	changed = strings_list_diff(prev_utmp_ptr, utmp_ptr);

	if (prev_utmp_ptr) {

		strings_list_free(prev_utmp_ptr);

	}

	return changed;

}

static void watch_file(int inotify_fd, const char *file)

{

	struct stringsList *ptr = utmp_ptr;

	while (ptr) {

		struct passwd *pwd = getpwnam(ptr->string);

		if (pwd) {

			char *path = NULL;

			if (asprintf(&path, "%s%s", pwd->pw_dir, file) < 0)

				exitApp("Error allocating memory.");

			watch_list_add(inotify_fd, path);

			free(path);

		}

		ptr = ptr->next;

	}

}

void utmpwatcher_add(int inotify_fd, const char *path)

{

	if (utmp_ptr == NULL) {

		utmpwatcher_handle(inotify_fd, utmp_wd);

	}

	watch_file(inotify_fd, path);

}

void utmpwatcher_free(void)

{

	if (utmp_ptr)

		strings_list_free(utmp_ptr);

}

#ifdef TEST

int main(int argc, char **argv)

{

	read_utmp();

	return 0;

}

#endif