1 /* $NetBSD: signal.c,v 1.5 2023/10/06 05:49:49 simonb Exp $ */
2
3 /*
4 * Copyright (C) 1984-2023 Mark Nudelman
5 *
6 * You may distribute under the terms of either the GNU General Public
7 * License or the Less License, as specified in the README file.
8 *
9 * For more information, see the README file.
10 */
11
12
13 /*
14 * Routines dealing with signals.
15 *
16 * A signal usually merely causes a bit to be set in the "signals" word.
17 * At some convenient time, the mainline code checks to see if any
18 * signals need processing by calling psignal().
19 * If we happen to be reading from a file [in iread()] at the time
20 * the signal is received, we call intread to interrupt the iread.
21 */
22
23 #include "less.h"
24 #include <signal.h>
25
26 /*
27 * "sigs" contains bits indicating signals which need to be processed.
28 */
29 public int sigs;
30
31 static RETSIGTYPE u_interrupt __P((int));
32 static RETSIGTYPE stop __P((int));
33 #if MSDOS_COMPILER==WIN32C
34 static BOOL WINAPI wbreak_handler __P((DWORD));
35 #endif
36
37 extern int sc_width, sc_height;
38 extern int screen_trashed;
39 extern int lnloop;
40 extern int linenums;
41 extern int wscroll;
42 extern int reading;
43 extern int quit_on_intr;
44 extern int secure;
45 extern long jump_sline_fraction;
46
47 /*
48 * Interrupt signal handler.
49 */
50 #if MSDOS_COMPILER!=WIN32C
51 /* ARGSUSED*/
u_interrupt(int type)52 static RETSIGTYPE u_interrupt(int type)
53 {
54 bell();
55 #if OS2
56 LSIGNAL(SIGINT, SIG_ACK);
57 #endif
58 LSIGNAL(SIGINT, u_interrupt);
59 sigs |= S_INTERRUPT;
60 #if MSDOS_COMPILER==DJGPPC
61 /*
62 * If a keyboard has been hit, it must be Ctrl-C
63 * (as opposed to Ctrl-Break), so consume it.
64 * (Otherwise, Less will beep when it sees Ctrl-C from keyboard.)
65 */
66 if (kbhit())
67 getkey();
68 #endif
69 #if HILITE_SEARCH
70 set_filter_pattern(NULL, 0);
71 #endif
72 if (reading)
73 intread(); /* May longjmp */
74 }
75 #endif
76
77 #ifdef SIGTSTP
78 /*
79 * "Stop" (^Z) signal handler.
80 */
81 /* ARGSUSED*/
stop(int type)82 static RETSIGTYPE stop(int type)
83 {
84 LSIGNAL(SIGTSTP, stop);
85 sigs |= S_STOP;
86 if (reading)
87 intread();
88 }
89 #endif
90
91 #undef SIG_LESSWINDOW
92 #ifdef SIGWINCH
93 #define SIG_LESSWINDOW SIGWINCH
94 #else
95 #ifdef SIGWIND
96 #define SIG_LESSWINDOW SIGWIND
97 #endif
98 #endif
99
100 #ifdef SIG_LESSWINDOW
101 /*
102 * "Window" change handler
103 */
104 /* ARGSUSED*/
winch(int type)105 public RETSIGTYPE winch(int type)
106 {
107 LSIGNAL(SIG_LESSWINDOW, winch);
108 sigs |= S_WINCH;
109 if (reading)
110 intread();
111 }
112 #endif
113
114 #if MSDOS_COMPILER==WIN32C
115 /*
116 * Handle CTRL-C and CTRL-BREAK keys.
117 */
118 #define WIN32_LEAN_AND_MEAN
119 #include <windows.h>
120
wbreak_handler(DWORD dwCtrlType)121 static BOOL WINAPI wbreak_handler(DWORD dwCtrlType)
122 {
123 switch (dwCtrlType)
124 {
125 case CTRL_C_EVENT:
126 case CTRL_BREAK_EVENT:
127 sigs |= S_INTERRUPT;
128 #if HILITE_SEARCH
129 set_filter_pattern(NULL, 0);
130 #endif
131 return (TRUE);
132 default:
133 break;
134 }
135 return (FALSE);
136 }
137 #endif
138
terminate(int type)139 static RETSIGTYPE terminate(int type)
140 {
141 quit(15);
142 }
143
144 /*
145 * Set up the signal handlers.
146 */
init_signals(int on)147 public void init_signals(int on)
148 {
149 if (on)
150 {
151 /*
152 * Set signal handlers.
153 */
154 #if MSDOS_COMPILER==WIN32C
155 SetConsoleCtrlHandler(wbreak_handler, TRUE);
156 #else
157 (void) LSIGNAL(SIGINT, u_interrupt);
158 #endif
159 #ifdef SIGTSTP
160 (void) LSIGNAL(SIGTSTP, secure ? SIG_IGN : stop);
161 #endif
162 #ifdef SIGWINCH
163 (void) LSIGNAL(SIGWINCH, winch);
164 #endif
165 #ifdef SIGWIND
166 (void) LSIGNAL(SIGWIND, winch);
167 #endif
168 #ifdef SIGQUIT
169 (void) LSIGNAL(SIGQUIT, SIG_IGN);
170 #endif
171 #ifdef SIGTERM
172 (void) LSIGNAL(SIGTERM, terminate);
173 #endif
174 } else
175 {
176 /*
177 * Restore signals to defaults.
178 */
179 #if MSDOS_COMPILER==WIN32C
180 SetConsoleCtrlHandler(wbreak_handler, FALSE);
181 #else
182 (void) LSIGNAL(SIGINT, SIG_DFL);
183 #endif
184 #ifdef SIGTSTP
185 (void) LSIGNAL(SIGTSTP, SIG_DFL);
186 #endif
187 #ifdef SIGWINCH
188 (void) LSIGNAL(SIGWINCH, SIG_IGN);
189 #endif
190 #ifdef SIGWIND
191 (void) LSIGNAL(SIGWIND, SIG_IGN);
192 #endif
193 #ifdef SIGQUIT
194 (void) LSIGNAL(SIGQUIT, SIG_DFL);
195 #endif
196 #ifdef SIGTERM
197 (void) LSIGNAL(SIGTERM, SIG_DFL);
198 #endif
199 }
200 }
201
202 /*
203 * Process any signals we have received.
204 * A received signal cause a bit to be set in "sigs".
205 */
psignals(void)206 public void psignals(void)
207 {
208 int tsignals;
209
210 if ((tsignals = sigs) == 0)
211 return;
212 sigs = 0;
213
214 #ifdef SIGTSTP
215 if (tsignals & S_STOP)
216 {
217 /*
218 * Clean up the terminal.
219 */
220 #ifdef SIGTTOU
221 LSIGNAL(SIGTTOU, SIG_IGN);
222 #endif
223 clear_bot();
224 deinit();
225 flush();
226 raw_mode(0);
227 #ifdef SIGTTOU
228 LSIGNAL(SIGTTOU, SIG_DFL);
229 #endif
230 LSIGNAL(SIGTSTP, SIG_DFL);
231 kill(getpid(), SIGTSTP);
232 /*
233 * ... Bye bye. ...
234 * Hopefully we'll be back later and resume here...
235 * Reset the terminal and arrange to repaint the
236 * screen when we get back to the main command loop.
237 */
238 LSIGNAL(SIGTSTP, stop);
239 raw_mode(1);
240 init();
241 screen_trashed = 1;
242 tsignals |= S_WINCH;
243 }
244 #endif
245 #ifdef S_WINCH
246 if (tsignals & S_WINCH)
247 {
248 int old_width, old_height;
249 /*
250 * Re-execute scrsize() to read the new window size.
251 */
252 old_width = sc_width;
253 old_height = sc_height;
254 get_term();
255 if (sc_width != old_width || sc_height != old_height)
256 {
257 wscroll = (sc_height + 1) / 2;
258 calc_jump_sline();
259 calc_shift_count();
260 }
261 screen_trashed = 1;
262 }
263 #endif
264 if (tsignals & S_INTERRUPT)
265 {
266 if (quit_on_intr)
267 quit(QUIT_INTERRUPT);
268 }
269 }
270