/*-
 * Copyright (c) 2014 Baptiste Daroussin <bapt@FreeBSD.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
 *    in this position and unchanged.
 * 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.
 *~
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``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 AUTHOR(S) 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 <sys/types.h>
#include <sys/event.h>
#include <sys/time.h>
#include <sys/wait.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <getopt.h>
#include <err.h>
#include <spawn.h>
#include <errno.h>
#include <stdbool.h>

#define EXIT_TIMEOUT 124

extern char **environ;

static void
usage(void)
{
	fprintf(stderr, "Usage: %s [OPTIONS] <duration> <command>\n", getprogname());
	exit(EXIT_FAILURE);
}

static double
parse_duration(const char *duration)
{
	double ret;
	char *end;

	ret = strtod(duration, &end);
	if (ret == 0 && end == duration)
		errx(EXIT_FAILURE, "invalid duration");

	if (end == NULL || *end == '\0')
		return (ret);

	if (end != NULL && *(end + 1) == '\0')
		errx(EXIT_FAILURE, "invalid duration");

	switch (*end) {
	case 's':
		break;
	case 'm':
		ret *= 60;
		break;
	case 'h':
		ret *= 60 * 60;
		break;
	case 'd':
		ret *= 60 * 60 * 24;
		break;
	default:
		errx(EXIT_FAILURE, "invalid duration");
	}

	return (ret);
}

static int
parse_signal(const char *str)
{
	int sig, i;
	const char *err;

	sig = strtonum(str, 1, sys_nsig, &err);

	if (err == NULL)
		return (sig);

	if (strncasecmp(str, "SIG", 3) == 0)
		str += 3;

	for (i = 1; i < sys_nsig; i++) {
		if (strcasecmp(str, sys_signame[i]) == 0)
			return (i);
	}

	errx(EXIT_FAILURE, "invalid signal");

}

int
main(int argc, char **argv)
{
	int ch, kq, nev, i;
	int foreground, preserve;
	int error, pstat, sig;
	int killsig = SIGTERM;
	pid_t pgid, pid;
	double first_kill;
	double second_kill;
	struct kevent ke, evlist[2];
	bool timedout = false;

	foreground = preserve = 0;

	struct option longopts[] = {
		{ "preserve-status", no_argument,       &preserve,    1 },
		{ "foreground",      no_argument,       &foreground,  1 },
		{ "kill-after",      required_argument, NULL,        'k'},
		{ "signal",          required_argument, NULL,        's'},
		{ "help",            no_argument,       NULL,        'h'},
		{ NULL,              0,                 NULL,         0 }
	};

	while ((ch = getopt_long(argc, argv, "k:s:h", longopts, NULL)) != -1) {
		switch (ch) {
			case 'k':
				second_kill = parse_duration(optarg);
				break;
			case 's':
				killsig = parse_signal(optarg);
				break;
			case 0:
				break;
			case 'h':
			default:
				usage();
				break;
		}
	}

	argc -= optind;
	argv += optind;

	if (argc < 2)
		usage();

	first_kill = parse_duration(argv[0]);
	argc--;
	argv++;

	if (!foreground)
		pgid = setpgid(0,0);

	if ((error = posix_spawnp(&pid, argv[0], NULL, NULL, argv, environ)) != 0) {
		errno = error;
		err(EXIT_FAILURE, "posix_spawn()");
	}

	kq = kqueue();

	EV_SET(&ke, 1, EVFILT_TIMER, EV_ADD|EV_ONESHOT, 0, first_kill * 1000, NULL);
	kevent(kq, &ke, 1, NULL, 0, NULL);

	EV_SET(&ke, pid, EVFILT_PROC, EV_ADD, NOTE_EXIT, 0, NULL);
	kevent(kq, &ke, 1, NULL, 0, NULL);

	for (;;) {
		nev = kevent(kq, NULL, 0, evlist, 2, NULL);
		for (i = 0; i < nev; i++) {
			if (evlist[i].filter == EVFILT_PROC) {
				pstat = evlist[i].data;
				if (WEXITSTATUS(pstat) != 0)
					pstat = WEXITSTATUS(pstat);
				else if (WIFSIGNALED (pstat)) {
					sig = WTERMSIG (pstat);
					if (!timedout) {
						signal(sig, SIG_DFL);
						raise(sig);
					}
					pstat = sig + 128;
				}
				if (timedout && !preserve)
					return (EXIT_TIMEOUT);

				return (pstat);
			}

			if (evlist[i].filter == EVFILT_TIMER) {
				timedout = true;
				if (second_kill) {
					EV_SET(&ke, 1, EVFILT_TIMER, EV_ADD|EV_ONESHOT, 0, second_kill * 1000, NULL);
					kevent(kq, &ke, 1, NULL, 0, NULL);
				}
				if (pgid)
					killpg(pgid, killsig);
				else
					kill(pid, killsig);
			}
		}

	}

	return (pstat);
}