/*
 * Ejemplo de control de subprocesos:
 *	primer parametro:  Num. maximo de segundos
 *	segundo y sucesivos: proceso a ejecutar
 * Nota: se deberia usar primero kill -TERM, y si falla, -KILL, no -KILL
 * directamente.
 */

#include <stdio.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/wait.h>

int launch( char *cmd[], int time, int *status );

extern int errno;

char	*app;

main(int argc, char **argv )
{
	char *excmd[2]={NULL,NULL};
	int error, status;

	if (argc < 3 )
	{
		fprintf(stderr,"%s: SPDsoft 1994\n", argv[0]);
		fprintf(stderr,"Use %s: Max_seconds Cmd [arg...]\n", argv[0]);
		fprintf(stderr,
"Cmd will be executed, and aborted (if still alive) after Max_seconds\n");
		exit(-1);
	}

	app = argv[0];
	excmd[0]=argv[2];

	if(0==(error=launch( &argv[2], atoi(argv[1]), &status)))
	{
		exit(status);
	}
	else if (error == -4)
	{
		fprintf(stderr,"%s: %s aborted after %s seconds\n",
		argv[0],argv[2],argv[1]);
		exit(error);
	}
	else
	{
		fprintf(stderr,"%s: %s failed (%d)\n",
		argv[0],argv[2],error);
		exit(error);
	}

}

int launch( char *cmd[], int time, int *status )
{
	int res=0;
	int st, alive=0;
	int pid, wdog_pid, wpid;
	char stime[256];
	char *wdog[3]={"sleep",NULL,NULL};

	wdog[1]=stime;
	sprintf( wdog[1], "%d", time);

	switch ( pid = fork() )
	{
	case -1:	/* error */
			perror ( "fork" );
			res = -1;
			break;

	case 0:		execvp ( cmd[0], &cmd[0] );
			fprintf(stderr, "%s: execvp %s: %s\n",
			app, cmd[0], strerror(errno));
			exit(-2);
			break;

	default:	
			*status = 0;
			if((wdog_pid=fork())==0)
			{
				execvp ( wdog[0], &wdog[0] );
				perror("fork wdog");
				exit(-5);
			}
			else if(wdog_pid == -1)
			{
				perror("fork wdog");
				res = -3;
			}
			else
			{
				/* esperando un final */

				alive = 1;

				while ( pid !=(wpid= wait ( &st )) )
				if ( wpid == wdog_pid )
				{
					/* sleep acaba antes */
					kill( pid, 9 );
					res=-4;
					alive = 0;
				}

				if(alive) kill(wdog_pid,9);

				if (res!=-4)
				{
				if (WIFSTOPPED(st))
				{
				printf("%s: %s stoped %d\n",
				app, cmd[0], WSTOPSIG(st));
				res = -6;
				}
				else if(WIFEXITED(st))
				{
					*status = WEXITSTATUS(st);
				}
				else if(WIFSIGNALED(st))
				{
				printf("%s: %s signaled %d\n",
				app, cmd[0],WTERMSIG(st));
				res = -6;
				}

				if(st&0200)
					printf("%s: %s core dumped\n",
					app, cmd[0]);

				}
				wait(&st);
			}
			break;

	}   /* Fin del   switch */

	return res;
}