/*++
/* NAME
/*	timeout 1
/* SUMMARY
/*	run command with bounded time
/* SYNOPSIS
/*	\fBtimeout\fR [-\fIsignal\fR] \fItime\fR \fIcommand\fR ...
/* DESCRIPTION
/*	\fBtimeout\fR executes a command and imposes an elapsed time limit.
/*	The command is run in a separate POSIX process group so that the
/*	right thing happens with commands that spawn child processes.
/*
/*	Arguments:
/* .IP \fI-signal\fR
/*	Specify an optional signal to send to the controlled process.
/*	By default, \fBtimeout\fR sends SIGKILL, which cannot be caught
/*	or ignored.
/* .IP \fItime\fR
/*	The elapsed time limit after which the command is terminated.
/* .IP \fIcommand\fR
/*	The command to be executed.
/* DIAGNOSTICS
/*	The command exit status is the exit status of the command
/*	(status 1 in case of a usage error).
/* AUTHOR(S)
/*	Wietse Venema
/*	This program is part of SATAN.
/*--*/

/* System libraries. */

#include <sys/types.h>
#include <signal.h>
#include <stdlib.h>
#include <unistd.h>
#include <stdio.h>

extern int optind;

/* Application-specific. */

#define perrorexit(s) { perror(s); exit(1); }

static int kill_signal = SIGKILL;
static char *progname;
static char *commandname;

static void usage()
{
    fprintf(stderr, "usage: %s [-signal] time command...\n", progname);
    exit(1);
}

static void terminate(sig)
int     sig;
{
    signal(kill_signal, SIG_DFL);
    fprintf(stderr, "Timeout: aborting command ``%s'' with signal %d\n",
	    commandname, kill_signal);
    kill(0, kill_signal);
}

int     main(argc, argv)
int     argc;
char  **argv;
{
    int     time_to_run;
    pid_t   pid;
    pid_t   child_pid;
    int     status;

    progname = argv[0];

    /*
     * Parse JCL.
     */
    while (--argc && *++argv && **argv == '-')
	if ((kill_signal = atoi(*argv + 1)) <= 0)
	    usage();

    if (argc < 2 || (time_to_run = atoi(argv[0])) <= 0)
	usage();

    commandname = argv[1];

    /*
     * Run the command and its watchdog in a separate process group so that
     * both can be killed off with one signal.
     */
    setsid();
    switch (child_pid = fork()) {
    case -1:					/* error */
	perrorexit("timeout: fork");
    case 00:					/* run controlled command */
	execvp(argv[1], argv + 1);
	perrorexit(argv[1]);
    default:					/* become watchdog */
	(void) signal(SIGHUP, terminate);
	(void) signal(SIGINT, terminate);
	(void) signal(SIGQUIT, terminate);
	(void) signal(SIGTERM, terminate);
	(void) signal(SIGALRM, terminate);
	alarm(time_to_run);
	while ((pid = wait(&status)) != -1 && pid != child_pid)
	     /* void */ ;
	return (pid == child_pid ? status : -1);
    }
}
