1 /*
2 * Copyright (C) 1984-2021 Mark Nudelman
3 *
4 * You may distribute under the terms of either the GNU General Public
5 * License or the Less License, as specified in the README file.
6 *
7 * For more information, see the README file.
8 */
9
10 /* $FreeBSD$ */
11
12 /*
13 * Routines dealing with signals.
14 *
15 * A signal usually merely causes a bit to be set in the "signals" word.
16 * At some convenient time, the mainline code checks to see if any
17 * signals need processing by calling psignal().
18 * If we happen to be reading from a file [in iread()] at the time
19 * the signal is received, we call intread to interrupt the iread.
20 */
21
22 #include "less.h"
23 #include <signal.h>
24
25 /*
26 * "sigs" contains bits indicating signals which need to be processed.
27 */
28 public int sigs;
29
30 extern int sc_width, sc_height;
31 extern int screen_trashed;
32 extern int lnloop;
33 extern int linenums;
34 extern int wscroll;
35 extern int reading;
36 extern int quit_on_intr;
37 extern int secure;
38 extern long jump_sline_fraction;
39
40 extern int less_is_more;
41
42 /*
43 * Interrupt signal handler.
44 */
45 #if MSDOS_COMPILER!=WIN32C
46 /* ARGSUSED*/
47 static RETSIGTYPE
u_interrupt(type)48 u_interrupt(type)
49 int type;
50 {
51 bell();
52 #if OS2
53 LSIGNAL(SIGINT, SIG_ACK);
54 #endif
55 LSIGNAL(SIGINT, u_interrupt);
56 sigs |= S_INTERRUPT;
57 #if MSDOS_COMPILER==DJGPPC
58 /*
59 * If a keyboard has been hit, it must be Ctrl-C
60 * (as opposed to Ctrl-Break), so consume it.
61 * (Otherwise, Less will beep when it sees Ctrl-C from keyboard.)
62 */
63 if (kbhit())
64 getkey();
65 #endif
66 if (less_is_more)
67 quit(0);
68 #if HILITE_SEARCH
69 set_filter_pattern(NULL, 0);
70 #endif
71 if (reading)
72 intread(); /* May longjmp */
73 }
74 #endif
75
76 #ifdef SIGTSTP
77 /*
78 * "Stop" (^Z) signal handler.
79 */
80 /* ARGSUSED*/
81 static RETSIGTYPE
stop(type)82 stop(type)
83 int type;
84 {
85 LSIGNAL(SIGTSTP, stop);
86 sigs |= S_STOP;
87 if (reading)
88 intread();
89 }
90 #endif
91
92 #undef SIG_LESSWINDOW
93 #ifdef SIGWINCH
94 #define SIG_LESSWINDOW SIGWINCH
95 #else
96 #ifdef SIGWIND
97 #define SIG_LESSWINDOW SIGWIND
98 #endif
99 #endif
100
101 #ifdef SIG_LESSWINDOW
102 /*
103 * "Window" change handler
104 */
105 /* ARGSUSED*/
106 public RETSIGTYPE
winch(type)107 winch(type)
108 int type;
109 {
110 LSIGNAL(SIG_LESSWINDOW, winch);
111 sigs |= S_WINCH;
112 if (reading)
113 intread();
114 }
115 #endif
116
117 #if MSDOS_COMPILER==WIN32C
118 /*
119 * Handle CTRL-C and CTRL-BREAK keys.
120 */
121 #define WIN32_LEAN_AND_MEAN
122 #include <windows.h>
123
124 static BOOL WINAPI
wbreak_handler(dwCtrlType)125 wbreak_handler(dwCtrlType)
126 DWORD dwCtrlType;
127 {
128 switch (dwCtrlType)
129 {
130 case CTRL_C_EVENT:
131 case CTRL_BREAK_EVENT:
132 sigs |= S_INTERRUPT;
133 #if HILITE_SEARCH
134 set_filter_pattern(NULL, 0);
135 #endif
136 return (TRUE);
137 default:
138 break;
139 }
140 return (FALSE);
141 }
142 #endif
143
144 static RETSIGTYPE
terminate(type)145 terminate(type)
146 int type;
147 {
148 quit(15);
149 }
150
151 /*
152 * Set up the signal handlers.
153 */
154 public void
init_signals(on)155 init_signals(on)
156 int on;
157 {
158 if (on)
159 {
160 /*
161 * Set signal handlers.
162 */
163 #if MSDOS_COMPILER==WIN32C
164 SetConsoleCtrlHandler(wbreak_handler, TRUE);
165 #else
166 (void) LSIGNAL(SIGINT, u_interrupt);
167 #endif
168 #ifdef SIGTSTP
169 (void) LSIGNAL(SIGTSTP, secure ? SIG_IGN : stop);
170 #endif
171 #ifdef SIGWINCH
172 (void) LSIGNAL(SIGWINCH, winch);
173 #endif
174 #ifdef SIGWIND
175 (void) LSIGNAL(SIGWIND, winch);
176 #endif
177 #ifdef SIGQUIT
178 (void) LSIGNAL(SIGQUIT, SIG_IGN);
179 #endif
180 #ifdef SIGTERM
181 (void) LSIGNAL(SIGTERM, terminate);
182 #endif
183 } else
184 {
185 /*
186 * Restore signals to defaults.
187 */
188 #if MSDOS_COMPILER==WIN32C
189 SetConsoleCtrlHandler(wbreak_handler, FALSE);
190 #else
191 (void) LSIGNAL(SIGINT, SIG_DFL);
192 #endif
193 #ifdef SIGTSTP
194 (void) LSIGNAL(SIGTSTP, SIG_DFL);
195 #endif
196 #ifdef SIGWINCH
197 (void) LSIGNAL(SIGWINCH, SIG_IGN);
198 #endif
199 #ifdef SIGWIND
200 (void) LSIGNAL(SIGWIND, SIG_IGN);
201 #endif
202 #ifdef SIGQUIT
203 (void) LSIGNAL(SIGQUIT, SIG_DFL);
204 #endif
205 #ifdef SIGTERM
206 (void) LSIGNAL(SIGTERM, SIG_DFL);
207 #endif
208 }
209 }
210
211 /*
212 * Process any signals we have received.
213 * A received signal cause a bit to be set in "sigs".
214 */
215 public void
psignals(VOID_PARAM)216 psignals(VOID_PARAM)
217 {
218 int tsignals;
219
220 if ((tsignals = sigs) == 0)
221 return;
222 sigs = 0;
223
224 #ifdef SIGTSTP
225 if (tsignals & S_STOP)
226 {
227 /*
228 * Clean up the terminal.
229 */
230 #ifdef SIGTTOU
231 LSIGNAL(SIGTTOU, SIG_IGN);
232 #endif
233 clear_bot();
234 deinit();
235 flush();
236 raw_mode(0);
237 #ifdef SIGTTOU
238 LSIGNAL(SIGTTOU, SIG_DFL);
239 #endif
240 LSIGNAL(SIGTSTP, SIG_DFL);
241 kill(getpid(), SIGTSTP);
242 /*
243 * ... Bye bye. ...
244 * Hopefully we'll be back later and resume here...
245 * Reset the terminal and arrange to repaint the
246 * screen when we get back to the main command loop.
247 */
248 LSIGNAL(SIGTSTP, stop);
249 raw_mode(1);
250 init();
251 screen_trashed = 1;
252 tsignals |= S_WINCH;
253 }
254 #endif
255 #ifdef S_WINCH
256 if (tsignals & S_WINCH)
257 {
258 int old_width, old_height;
259 /*
260 * Re-execute scrsize() to read the new window size.
261 */
262 old_width = sc_width;
263 old_height = sc_height;
264 get_term();
265 if (sc_width != old_width || sc_height != old_height)
266 {
267 wscroll = (sc_height + 1) / 2;
268 calc_jump_sline();
269 calc_shift_count();
270 }
271 screen_trashed = 1;
272 }
273 #endif
274 if (tsignals & S_INTERRUPT)
275 {
276 if (quit_on_intr)
277 quit(QUIT_INTERRUPT);
278 }
279 }
280