bin/ksh/tty.c

   1 /*      $OpenBSD: tty.c,v 1.17 2018/03/15 16:51:29 anton Exp $  */
   2
   3 #include <errno.h>
   4 #include <fcntl.h>
   5 #include <string.h>
   6 #include <unistd.h>
   7
   8 #include "sh.h"
   9 #include "tty.h"
  10
  11 int             tty_fd = -1;    /* dup'd tty file descriptor */
  12 int             tty_devtty;     /* true if tty_fd is from /dev/tty */
  13 struct termios  tty_state;      /* saved tty state */
  14
  15 void
  16 tty_close(void)
  17 {
  18         if (tty_fd >= 0) {
  19                 close(tty_fd);
  20                 tty_fd = -1;
  21         }
  22 }
  23
  24 /* Initialize tty_fd.  Used for saving/resetting tty modes upon
  25  * foreground job completion and for setting up tty process group.
  26  */
  27 void
  28 tty_init(int init_ttystate)
  29 {
  30         int     do_close = 1;
  31         int     tfd;
  32
  33         tty_close();
  34         tty_devtty = 1;
  35
  36         tfd = open("/dev/tty", O_RDWR, 0);
  37         if (tfd < 0) {
  38                 tty_devtty = 0;
  39                 warningf(false, "No controlling tty (open /dev/tty: %s)",
  40                     strerror(errno));
  41
  42                 do_close = 0;
  43                 if (isatty(0))
  44                         tfd = 0;
  45                 else if (isatty(2))
  46                         tfd = 2;
  47                 else {
  48                         warningf(false, "Can't find tty file descriptor");
  49                         return;
  50                 }
  51         }
  52         if ((tty_fd = fcntl(tfd, F_DUPFD_CLOEXEC, FDBASE)) < 0) {
  53                 warningf(false, "%s: dup of tty fd failed: %s",
  54                     __func__, strerror(errno));
  55         } else if (init_ttystate)
  56                 tcgetattr(tty_fd, &tty_state);
  57         if (do_close)
  58                 close(tfd);
  59 }