1 /****************************************************************************
2 * Copyright 2020 Thomas E. Dickey *
3 * Copyright 2016,2017 Free Software Foundation, Inc. *
4 * *
5 * Permission is hereby granted, free of charge, to any person obtaining a *
6 * copy of this software and associated documentation files (the *
7 * "Software"), to deal in the Software without restriction, including *
8 * without limitation the rights to use, copy, modify, merge, publish, *
9 * distribute, distribute with modifications, sublicense, and/or sell *
10 * copies of the Software, and to permit persons to whom the Software is *
11 * furnished to do so, subject to the following conditions: *
12 * *
13 * The above copyright notice and this permission notice shall be included *
14 * in all copies or substantial portions of the Software. *
15 * *
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS *
17 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF *
18 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. *
19 * IN NO EVENT SHALL THE ABOVE COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, *
20 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR *
21 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR *
22 * THE USE OR OTHER DEALINGS IN THE SOFTWARE. *
23 * *
24 * Except as contained in this notice, the name(s) of the above copyright *
25 * holders shall not be used in advertising or otherwise to promote the *
26 * sale, use or other dealings in this Software without prior written *
27 * authorization. *
28 ****************************************************************************/
29
30 /****************************************************************************
31 * Author: Thomas E. Dickey *
32 ****************************************************************************/
33
34 #define USE_LIBTINFO
35 #include <tty_settings.h>
36
37 #include <fcntl.h>
38
39 MODULE_ID("$Id: tty_settings.c,v 1.6 2020/02/02 23:34:34 tom Exp $")
40
41 static int my_fd;
42 static TTY original_settings;
43 static bool can_restore = FALSE;
44
45 static void
failed(const char * msg)46 failed(const char *msg)
47 {
48 int code = errno;
49
50 (void) fprintf(stderr, "%s: %s: %s\n", _nc_progname, msg, strerror(code));
51 restore_tty_settings();
52 (void) fprintf(stderr, "\n");
53 ExitProgram(ErrSystem(code));
54 /* NOTREACHED */
55 }
56
57 static bool
get_tty_settings(int fd,TTY * tty_settings)58 get_tty_settings(int fd, TTY * tty_settings)
59 {
60 bool success = TRUE;
61 my_fd = fd;
62 if (fd < 0 || GET_TTY(my_fd, tty_settings) < 0) {
63 success = FALSE;
64 }
65 return success;
66 }
67
68 /*
69 * Open a file descriptor on the current terminal, to obtain its settings.
70 * stderr is less likely to be redirected than stdout; try that first.
71 */
72 int
save_tty_settings(TTY * tty_settings,bool need_tty)73 save_tty_settings(TTY * tty_settings, bool need_tty)
74 {
75 if (!get_tty_settings(STDERR_FILENO, tty_settings) &&
76 !get_tty_settings(STDOUT_FILENO, tty_settings) &&
77 !get_tty_settings(STDIN_FILENO, tty_settings) &&
78 !get_tty_settings(open("/dev/tty", O_RDWR), tty_settings)) {
79 if (need_tty) {
80 failed("terminal attributes");
81 } else {
82 my_fd = fileno(stdout);
83 }
84 } else {
85 can_restore = TRUE;
86 original_settings = *tty_settings;
87 }
88 return my_fd;
89 }
90
91 void
restore_tty_settings(void)92 restore_tty_settings(void)
93 {
94 if (can_restore)
95 SET_TTY(my_fd, &original_settings);
96 }
97
98 /* Set the modes if they've changed. */
99 void
update_tty_settings(TTY * old_settings,TTY * new_settings)100 update_tty_settings(TTY * old_settings, TTY * new_settings)
101 {
102 if (memcmp(new_settings, old_settings, sizeof(TTY))) {
103 SET_TTY(my_fd, new_settings);
104 }
105 }
106