/*
 * lxc: linux Container library
 *
 * (C) Copyright IBM Corp. 2007, 2008
 *
 * Authors:
 * Daniel Lezcano <daniel.lezcano at free.fr>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <libgen.h>
#include <unistd.h>
#include <regex.h>
#include <sys/types.h>

#include <lxc/lxc.h>
#include <lxc/log.h>
#include <lxc/monitor.h>
#include "arguments.h"

lxc_log_define(lxc_monitor_ui, lxc_monitor);

static const struct option my_longopts[] = {
	LXC_COMMON_OPTIONS
};

static struct lxc_arguments my_args = {
	.progname = "lxc-monitor",
	.help     = "\
[--name=NAME]\n\
\n\
lxc-monitor monitors the state of the NAME container\n\
\n\
Options :\n\
  -n, --name=NAME   NAME for name of the container\n\
                    NAME may be a regular expression",
	.name     = ".*",
	.options  = my_longopts,
	.parser   = NULL,
	.checker  = NULL,
	.lxcpath_additional = -1,
};

int main(int argc, char *argv[])
{
	char *regexp;
	struct lxc_msg msg;
	regex_t preg;
	fd_set rfds, rfds_save;
	int len, rc, i, nfds = -1;

	if (lxc_arguments_parse(&my_args, argc, argv))
		return -1;

	if (!my_args.log_file)
		my_args.log_file = "none";

	if (lxc_log_init(my_args.name, my_args.log_file, my_args.log_priority,
			 my_args.progname, my_args.quiet, my_args.lxcpath[0]))
		return -1;

	len = strlen(my_args.name) + 3;
	regexp = malloc(len + 3);
	if (!regexp) {
		ERROR("failed to allocate memory");
		return -1;
	}
	rc = snprintf(regexp, len, "^%s$", my_args.name);
	if (rc < 0 || rc >= len) {
		ERROR("Name too long");
		free(regexp);
		return -1;
	}

	if (regcomp(&preg, regexp, REG_NOSUB|REG_EXTENDED)) {
		ERROR("failed to compile the regex '%s'", my_args.name);
		return -1;
	}

	if (my_args.lxcpath_cnt > FD_SETSIZE) {
		ERROR("too many paths requested, only the first %d will be monitored", FD_SETSIZE);
		my_args.lxcpath_cnt = FD_SETSIZE;
	}

	FD_ZERO(&rfds);
	for (i = 0; i < my_args.lxcpath_cnt; i++) {
		int fd;

		lxc_monitord_spawn(my_args.lxcpath[i]);

		fd = lxc_monitor_open(my_args.lxcpath[i]);
		if (fd < 0)
			return -1;
		FD_SET(fd, &rfds);
		if (fd > nfds)
			nfds = fd;
	}
	memcpy(&rfds_save, &rfds, sizeof(rfds_save));
	nfds++;

	setlinebuf(stdout);

	for (;;) {
		memcpy(&rfds, &rfds_save, sizeof(rfds));

		if (lxc_monitor_read_fdset(&rfds, nfds, &msg, -1) < 0)
			return -1;

		msg.name[sizeof(msg.name)-1] = '\0';
		if (regexec(&preg, msg.name, 0, NULL, 0))
			continue;

		switch (msg.type) {
		case lxc_msg_state:
			printf("'%s' changed state to [%s]\n",
			       msg.name, lxc_state2str(msg.value));
			break;
		default:
			/* ignore garbage */
			break;
		}
	}

	regfree(&preg);

	return 0;
}
