/* 
*	set time limit on a process 
* 
*  Yunliang Yu <yu@math.duke.edu>
* 
*  time ./a.out -10 ./a.out -50 sleep 56
*  
*/

#include <stdio.h>
#include <signal.h>

int pid;	/* child process id */
char *progname;
void onalarm(int s);

main(int argc,char** argv)
{
	int sec=5,status,atoi();

	progname=argv[0];
	if (argc>1 && argv[1][0] == '-')
	{	sec=atoi(&argv[1][1]);
		argc--;
		argv++;
	}
	if (argc<2)
	{
		fprintf(stderr,"Usage: %s [-5(seconds)] command args\n",progname);
		exit(1);
	}
	if ((pid=fork())==0)
	{	execvp(argv[1],&argv[1]);
		fprintf(stderr,"couldn't start %s\n",argv[1]);
		exit(1);
	}
	signal(SIGALRM, onalarm);
	alarm(sec);
	if (wait(&status) == -1 || (status & 0177) != 0)
	{
		exit(1);
	}
	exit(1);
}

void onalarm(int s)
{
	kill(/* 0 */ pid, SIGKILL); /* process group of the current process? */
}