1 /* $OpenBSD: tty.c,v 1.19 2021/10/24 21:24:21 deraadt 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
tty_close(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
tty_init(int init_ttystate)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);
37 if (tfd == -1) {
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)) == -1) {
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 }
60