#include <stdio.h>
#include <signal.h>
#include <errno.h>
#include <unistd.h>
#include <sys/time.h>
#include <sys/types.h>


#include <unistd.h>
#include <fcntl.h>

#define BUFSIZE	128

int read_to_buffer(int fd, char *buf);
int sh_unset_nodelay_mode (int fd);
int give_terminal_to (pid_t pgrp, int shell_tty, int force);

/* Function int main(int argc, char **argv) {{{ */
int main(int argc, char **argv)
{
	register int ret, pid;
	int pipe0[2], pipe1[2], pipe2[2];
	char buf[BUFSIZE];
	fd_set fds;

	if (argc <= 1) {
		printf("Usage: %s <command>\n", argv[0]);
		return 1;
	}

	if (pipe(pipe0)
							|| pipe(pipe1)
							|| pipe(pipe2)) {
		puts("pipe() failure");
		return 1;
	}

	/*
	   fcntl(pipe1[1], F_SETFL, O_NONBLOCK|O_NDELAY);
	   fcntl(pipe2[1], F_SETFL, O_NONBLOCK|O_NDELAY);
	   */

	sh_unset_nodelay_mode(0);
	sh_unset_nodelay_mode(pipe1[1]);
	sh_unset_nodelay_mode(pipe1[2]);

	switch (pid = fork()) {
		case -1:
			puts("fork() failure");
			return 1;
			break;

		case 0: /* Child */
			if (dup2(pipe0[0], 0) == -1
									|| dup2(pipe1[1], 1) == -1
									|| dup2(pipe2[1], 2) == -1) {
				puts("dup2() failure");
				return 1;
			}

			close(pipe0[0]);
			close(pipe0[1]);
			close(pipe1[0]);
			close(pipe1[1]);
			close(pipe2[0]);
			close(pipe2[1]);

			execvp(argv[1], argv + 1);
			break;

		default: /* Parent */
			break;
	};

	give_terminal_to(pid, 1, 0);

	while (1) {

		FD_ZERO(&fds);
		FD_SET(0, &fds);
		FD_SET(pipe1[0], &fds);
		FD_SET(pipe2[0], &fds);

		switch (select(FD_SETSIZE, &fds, NULL, NULL, NULL)) {
			case -1:
				puts("select() failure");
				return 1;
				break;

			default:
				if (FD_ISSET(0, &fds)) {
					ret = read_to_buffer(0, buf);
					write(pipe0[1], buf, ret);
				}
				if (FD_ISSET(pipe1[0], &fds)) {
					ret = read_to_buffer(pipe1[0], buf);
					write(1, buf, ret);
				}
				if (FD_ISSET(pipe2[0], &fds)) {
					ret = read_to_buffer(pipe2[0], buf);
					write(2, buf, ret);
				}

				break;
		}
	}


	return 0;
} /* }}} */

int read_to_buffer(int fd, char *buf)
{
	register int ret;
	ret = read(fd, buf, BUFSIZE);

	if (ret < 0) {
		printf("read() error, returned %d\n", ret);
		exit(-1 * ret);
	}
	else if (ret == 0) {
		printf("read() == 0, terminating\n");
		exit(0);
	}

	return ret;
}

/* Make sure no-delay mode is not set on file descriptor FD. */
int sh_unset_nodelay_mode (int fd)
{
	int flags, bflags;

	if ((flags = fcntl (fd, F_GETFL, 0)) < 0)
		return -1;

	bflags = 0;

	/* This is defined to O_NDELAY in filecntl.h if O_NONBLOCK is not present
	   and O_NDELAY is defined. */
#ifdef O_NONBLOCK
	bflags |= O_NONBLOCK;
#endif

#ifdef O_NDELAY
	bflags |= O_NDELAY;
#endif

	if (flags & bflags)
	{
		flags &= ~bflags;
		return (fcntl (fd, F_SETFL, flags));
	}

	return 0;
}

/* Give the terminal to PGRP.  */
int give_terminal_to (pid_t pgrp, int shell_tty, int force)
{
	sigset_t set, oset;
	int r;

	r = 0;
	if (/* job_control ||*/ force) {
		sigemptyset (&set);
		sigaddset (&set, SIGTTOU);
		sigaddset (&set, SIGTTIN);
		sigaddset (&set, SIGTSTP);
		sigaddset (&set, SIGCHLD);
		sigemptyset (&oset);
		sigprocmask (SIG_BLOCK, &set, &oset);

		if (tcsetpgrp (shell_tty, pgrp) < 0) {
			/* Maybe we should print an error message? */
#if 0
			sys_error ("tcsetpgrp(%d) failed: pid %ld to pgrp %ld",
									shell_tty, (long)getpid(), (long)pgrp);
#endif
			r = -1;
		}
		else {
			/* terminal_pgrp = pgrp; */
		}

		sigprocmask (SIG_SETMASK, &oset, (sigset_t *)NULL);
	}

	return r;
}

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