1 /*
2 * Copyright (c) 1981, 1993
3 * The Regents of the University of California. All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. All advertising materials mentioning features or use of this software
14 * must display the following acknowledgement:
15 * This product includes software developed by the University of
16 * California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 */
33
34 #ifndef lint
35 static char sccsid[] = "@(#)tstp.c 8.2 (Berkeley) 1/2/94";
36 #endif /* not lint */
37
38 #include <curses.h>
39 #include <errno.h>
40 #include <signal.h>
41 #include <termios.h>
42 #include <unistd.h>
43
44
45 /*
46 * stop_signal_handler --
47 * Handle stop signals.
48 */
49 void
__stop_signal_handler(signo)50 __stop_signal_handler(signo)
51 int signo;
52 {
53 struct termios save;
54 sigset_t oset, set;
55
56 /* Get the current terminal state (which the user may have changed). */
57 if (tcgetattr(STDIN_FILENO, &save))
58 return;
59
60 /*
61 * Block window change and timer signals. The latter is because
62 * applications use timers to decide when to repaint the screen.
63 */
64 (void)sigemptyset(&set);
65 (void)sigaddset(&set, SIGALRM);
66 (void)sigaddset(&set, SIGWINCH);
67 (void)sigprocmask(SIG_BLOCK, &set, &oset);
68
69 /*
70 * End the window, which also resets the terminal state to the
71 * original modes.
72 */
73 endwin();
74
75 /* Unblock SIGTSTP. */
76 (void)sigemptyset(&set);
77 (void)sigaddset(&set, SIGTSTP);
78 (void)sigprocmask(SIG_UNBLOCK, &set, NULL);
79
80 /* Stop ourselves. */
81 __restore_stophandler();
82 (void)kill(0, SIGTSTP);
83
84 /* Time passes ... */
85
86 /* Reset the curses SIGTSTP signal handler. */
87 __set_stophandler();
88
89 /* save the new "default" terminal state */
90 (void)tcgetattr(STDIN_FILENO, &__orig_termios);
91
92 /* Reset the terminal state to the mode just before we stopped. */
93 (void)tcsetattr(STDIN_FILENO, __tcaction ?
94 TCSASOFT | TCSADRAIN : TCSADRAIN, &save);
95
96 /* Restart the screen. */
97 __startwin();
98
99 /* Repaint the screen. */
100 wrefresh(curscr);
101
102 /* Reset the signals. */
103 (void)sigprocmask(SIG_SETMASK, &oset, NULL);
104 }
105
106 static void (*otstpfn)() = SIG_DFL;
107
108 /*
109 * Set the TSTP handler.
110 */
111 void
__set_stophandler()112 __set_stophandler()
113 {
114 otstpfn = signal(SIGTSTP, __stop_signal_handler);
115 }
116
117 /*
118 * Restore the TSTP handler.
119 */
120 void
__restore_stophandler()121 __restore_stophandler()
122 {
123 (void)signal(SIGTSTP, otstpfn);
124 }
125