OpenBSD-4.6/bin/ksh/tty.c

/*	$OpenBSD: tty.c,v 1.9 2006/03/14 22:08:01 deraadt Exp $	*/

#include "sh.h"
#include <sys/stat.h>
#define EXTERN
#include "tty.h"
#undef EXTERN

/* Initialize tty_fd.  Used for saving/reseting tty modes upon
 * foreground job completion and for setting up tty process group.
 */
void
tty_init(int init_ttystate)
{
	int	do_close = 1;
	int	tfd;

	if (tty_fd >= 0) {
		close(tty_fd);
		tty_fd = -1;
	}
	tty_devtty = 1;

	if ((tfd = open("/dev/tty", O_RDWR, 0)) < 0) {
		tty_devtty = 0;
		warningf(false, "No controlling tty (open /dev/tty: %s)",
		    strerror(errno));
	}

	if (tfd < 0) {
		do_close = 0;
		if (isatty(0))
			tfd = 0;
		else if (isatty(2))
			tfd = 2;
		else {
			warningf(false, "Can't find tty file descriptor");
			return;
		}
	}
	if ((tty_fd = fcntl(tfd, F_DUPFD, FDBASE)) < 0) {
		warningf(false, "j_ttyinit: dup of tty fd failed: %s",
		    strerror(errno));
	} else if (fcntl(tty_fd, F_SETFD, FD_CLOEXEC) < 0) {
		warningf(false, "j_ttyinit: can't set close-on-exec flag: %s",
		    strerror(errno));
		close(tty_fd);
		tty_fd = -1;
	} else if (init_ttystate)
		tcgetattr(tty_fd, &tty_state);
	if (do_close)
		close(tfd);
}

void
tty_close(void)
{
	if (tty_fd >= 0) {
		close(tty_fd);
		tty_fd = -1;
	}
}