/*      $OpenBSD: tty.c,v 1.19 2021/10/24 21:24:21 deraadt Exp $        */

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

#include "sh.h"
#include "tty.h"

int             tty_fd = -1;    /* dup'd tty file descriptor */
int             tty_devtty;     /* true if tty_fd is from /dev/tty */
struct termios  tty_state;      /* saved tty state */

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

/* Initialize tty_fd.  Used for saving/resetting 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;

        tty_close();
        tty_devtty = 1;

        tfd = open("/dev/tty", O_RDWR);
        if (tfd == -1) {
                tty_devtty = 0;
                warningf(false, "No controlling tty (open /dev/tty: %s)",
                    strerror(errno));

                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_CLOEXEC, FDBASE)) == -1) {
                warningf(false, "%s: dup of tty fd failed: %s",
                    __func__, strerror(errno));
        } else if (init_ttystate)
                tcgetattr(tty_fd, &tty_state);
        if (do_close)
                close(tfd);
}