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

pid_t child_pid;
void print_usage(void){
	
	printf("usage: timeout <num> cmd\n");
}

void timedout(int signal){

	kill(child_pid, SIGTERM);
}

int main(int argc, char *argv[]){
	int secs;
	int child_status;

	if(argc <  3 ){
		print_usage();
		exit( 1 );
	}
	
	secs = atoi(argv[ 1 ]);
	if(secs <=  0 ){
		print_usage();
		exit( 1 );
	}

	switch(child_pid = fork()){
		case  0 :	execv(argv[ 2 ], argv +  2 );
				break;
		case - 1 :	printf("failed to execute command\n");
				break;
		default:	signal(SIGALRM, timedout);
				alarm(secs);
				wait(&child_status);
				return child_status;
	}
}