#include <err.h>
#include <fcntl.h>
#include <stdio.h>
#include <string.h>
#include <sys/select.h>
#include <unistd.h>

#define MAXBUF 2048

int
main()
{
	char bufin[MAXBUF], bufout[MAXBUF];
	fd_set rfds0, rfds1;
	int c, fdin, fdout, flags, i, nin, nout, state;
	struct timeval tv;

	if(!(fdin = open("/var/tmp/r.in", O_WRONLY)))
		err(1, "open");
	if(!(fdout = open("/var/tmp/r.out", O_RDONLY)))
		err(1, "open");

	flags = fcntl(0, F_GETFL, 0);
	flags |= O_NONBLOCK;
	fcntl(0, F_SETFL, flags);

	FD_ZERO(&rfds0);
	FD_ZERO(&rfds1);

	tv.tv_sec = 0;
	tv.tv_usec = 1;

	for(;;){
		/* Read from named pipe (out) and print on standard in. */
		FD_SET(fdout, &rfds1);
		if(select(fdout+1, &rfds1, NULL, NULL, &tv) > 0){
			nout = read(fdout, bufout, MAXBUF);
			bufout[nout] = 0;

			/* Ignore repetition of typed command. */
			if(strcmp(bufout, bufin) == 0)
				bufin[0] = 0;
			else{
				printf("%s", bufout);
				fflush(stdout);
			}
		}

		/* Read from standard in and print on named pipe (in). */
		FD_SET(0, &rfds0);
		if(select(0+1, &rfds0, NULL, NULL, &tv) > 0){
			nout = read(0, bufin, MAXBUF);
			bufin[nout] = 0;
			dprintf(fdin, "%s", bufin);
			fflush(stdout);
		}
	}

}