/* test-pipe.c - Steven Arnow <s@rdw.se>,  2014 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/wait.h>

#define	FD_SET_NO_BLOCK(fd) 	(fcntl(fd, F_SETFL, fcntl(fd, F_GETFL, 0) | O_NONBLOCK))


int main(int argc, char **argv) {
	int pipeout[2], pipeerr[2];
	int pid, sz, outa, erra, max;
	siginfo_t info;
	char buff[512];
	fd_set set;

	pipe(pipeout);
	pipe(pipeerr);
	pid = fork();
	
	if (!pid) {
		dup2(pipeout[1], STDOUT_FILENO);
		dup2(pipeerr[1], STDERR_FILENO);
		close(pipeout[0]);
		close(pipeerr[0]);
		system("./test");
		exit(-1);
	} else {
		close(pipeout[1]);
		close(pipeerr[1]);
		FD_SET_NO_BLOCK(pipeout[0]);
		FD_SET_NO_BLOCK(pipeerr[0]);
		outa = erra = 1;
		max = ((pipeout[1] > pipeerr[1]) ? pipeout[1] : pipeerr[1]) + 1;

		while (outa || erra) {
			FD_ZERO(&set);
			if (outa) FD_SET(pipeout[0], &set);
			if (erra) FD_SET(pipeerr[0], &set);
			select(max, &set, NULL, NULL, NULL);

			if (FD_ISSET(pipeout[0], &set)) {
				sz = read(pipeout[0], buff, 512);
				write(STDOUT_FILENO, buff, sz);
				if (sz <= 0) outa = 0;
			} if (FD_ISSET(pipeerr[0], &set)) {
				sz = read(pipeerr[0], buff, 512);
				write(STDERR_FILENO, buff, sz);
				if (sz <= 0) erra = 0;
			}
		}

		/* Wait for process to die */
		waitid(P_PID, pid, &info, WEXITED);
		if (info.si_code != CLD_EXITED) {
			fprintf(stderr, "===== Abnormal termination =====\n");
			return -1;
		}
	}

	return info.si_status;
}