1 /* $NetBSD: signals.c,v 1.1.1.1 2016/01/14 00:11:29 christos Exp $ */
2
3 /* signals.c -- install and maintain signal handlers.
4 Id: signals.c,v 1.7 2004/04/11 17:56:46 karl Exp
5
6 Copyright (C) 1993, 1994, 1995, 1998, 2002, 2003, 2004 Free Software
7 Foundation, Inc.
8
9 This program is free software; you can redistribute it and/or modify
10 it under the terms of the GNU General Public License as published by
11 the Free Software Foundation; either version 2, or (at your option)
12 any later version.
13
14 This program is distributed in the hope that it will be useful,
15 but WITHOUT ANY WARRANTY; without even the implied warranty of
16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 GNU General Public License for more details.
18
19 You should have received a copy of the GNU General Public License
20 along with this program; if not, write to the Free Software
21 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
22
23 Originally written by Brian Fox (bfox@ai.mit.edu). */
24
25 #include "info.h"
26 #include "signals.h"
27
28 void initialize_info_signal_handler (void);
29
30 /* **************************************************************** */
31 /* */
32 /* Pretending That We Have POSIX Signals */
33 /* */
34 /* **************************************************************** */
35
36 #if !defined (HAVE_SIGPROCMASK) && defined (HAVE_SIGSETMASK)
37 /* Perform OPERATION on NEWSET, perhaps leaving information in OLDSET. */
38 static void
sigprocmask(int operation,int * newset,int * oldset)39 sigprocmask (int operation, int *newset, int *oldset)
40 {
41 switch (operation)
42 {
43 case SIG_UNBLOCK:
44 sigsetmask (sigblock (0) & ~(*newset));
45 break;
46
47 case SIG_BLOCK:
48 *oldset = sigblock (*newset);
49 break;
50
51 case SIG_SETMASK:
52 sigsetmask (*newset);
53 break;
54
55 default:
56 abort ();
57 }
58 }
59 #endif /* !HAVE_SIGPROCMASK && HAVE_SIGSETMASK */
60
61 /* **************************************************************** */
62 /* */
63 /* Signal Handling for Info */
64 /* */
65 /* **************************************************************** */
66
67 #if defined (HAVE_SIGACTION) || defined (HAVE_SIGPROCMASK) ||\
68 defined (HAVE_SIGSETMASK)
69 static void
mask_termsig(sigset_t * set)70 mask_termsig (sigset_t *set)
71 {
72 # if defined (SIGTSTP)
73 sigaddset (set, SIGTSTP);
74 sigaddset (set, SIGTTOU);
75 sigaddset (set, SIGTTIN);
76 # endif
77 # if defined (SIGWINCH)
78 sigaddset (set, SIGWINCH);
79 # endif
80 #if defined (SIGQUIT)
81 sigaddset (set, SIGQUIT);
82 #endif
83 #if defined (SIGINT)
84 sigaddset (set, SIGINT);
85 #endif
86 # if defined (SIGUSR1)
87 sigaddset (set, SIGUSR1);
88 # endif
89 }
90 #endif /* HAVE_SIGACTION || HAVE_SIGPROCMASK || HAVE_SIGSETMASK */
91
92 static RETSIGTYPE info_signal_proc (int sig);
93 #if defined (HAVE_SIGACTION)
94 typedef struct sigaction signal_info;
95 signal_info info_signal_handler;
96
97 static void
set_termsig(int sig,signal_info * old)98 set_termsig (int sig, signal_info *old)
99 {
100 sigaction (sig, &info_signal_handler, old);
101 }
102
103 static void
restore_termsig(int sig,const signal_info * saved)104 restore_termsig (int sig, const signal_info *saved)
105 {
106 sigaction (sig, saved, NULL);
107 }
108 #else /* !HAVE_SIGACTION */
109 typedef RETSIGTYPE (*signal_info) ();
110 #define set_termsig(sig, old) (void)(*(old) = signal (sig, info_signal_proc))
111 #define restore_termsig(sig, saved) (void)signal (sig, *(saved))
112 #define info_signal_handler info_signal_proc
113 static int term_conf_busy = 0;
114 #endif /* !HAVE_SIGACTION */
115
116 static signal_info old_TSTP, old_TTOU, old_TTIN;
117 static signal_info old_WINCH, old_INT, old_USR1;
118 static signal_info old_QUIT;
119
120 void
initialize_info_signal_handler(void)121 initialize_info_signal_handler (void)
122 {
123 #ifdef SA_NOCLDSTOP
124 /* (Based on info from Paul Eggert found in coreutils.) Don't use
125 HAVE_SIGACTION to decide whether to use the sa_handler, sa_flags,
126 sa_mask members, as some systems (Solaris 7+) don't define them. Use
127 SA_NOCLDSTOP instead; it's been part of POSIX.1 since day 1 (in 1988). */
128 info_signal_handler.sa_handler = info_signal_proc;
129 info_signal_handler.sa_flags = 0;
130 mask_termsig (&info_signal_handler.sa_mask);
131 #endif /* SA_NOCLDSTOP */
132
133 #if defined (SIGTSTP)
134 set_termsig (SIGTSTP, &old_TSTP);
135 set_termsig (SIGTTOU, &old_TTOU);
136 set_termsig (SIGTTIN, &old_TTIN);
137 #endif /* SIGTSTP */
138
139 #if defined (SIGWINCH)
140 set_termsig (SIGWINCH, &old_WINCH);
141 #endif
142
143 #if defined (SIGQUIT)
144 set_termsig (SIGQUIT, &old_QUIT);
145 #endif
146
147 #if defined (SIGINT)
148 set_termsig (SIGINT, &old_INT);
149 #endif
150
151 #if defined (SIGUSR1)
152 /* Used by DJGPP to simulate SIGTSTP on Ctrl-Z. */
153 set_termsig (SIGUSR1, &old_USR1);
154 #endif
155 }
156
157 static void
redisplay_after_signal(void)158 redisplay_after_signal (void)
159 {
160 terminal_clear_screen ();
161 display_clear_display (the_display);
162 window_mark_chain (windows, W_UpdateWindow);
163 display_update_display (windows);
164 display_cursor_at_point (active_window);
165 fflush (stdout);
166 }
167
168 static void
reset_info_window_sizes(void)169 reset_info_window_sizes (void)
170 {
171 terminal_goto_xy (0, 0);
172 fflush (stdout);
173 terminal_unprep_terminal ();
174 terminal_get_screen_size ();
175 terminal_prep_terminal ();
176 display_initialize_display (screenwidth, screenheight);
177 window_new_screen_size (screenwidth, screenheight);
178 redisplay_after_signal ();
179 }
180
181 static RETSIGTYPE
info_signal_proc(int sig)182 info_signal_proc (int sig)
183 {
184 signal_info *old_signal_handler = NULL;
185
186 #if !defined (HAVE_SIGACTION)
187 /* best effort: first increment this counter and later block signals */
188 if (term_conf_busy)
189 return;
190 term_conf_busy++;
191 #if defined (HAVE_SIGPROCMASK) || defined (HAVE_SIGSETMASK)
192 {
193 sigset_t nvar, ovar;
194 sigemptyset (&nvar);
195 mask_termsig (&nvar);
196 sigprocmask (SIG_BLOCK, &nvar, &ovar);
197 }
198 #endif /* HAVE_SIGPROCMASK || HAVE_SIGSETMASK */
199 #endif /* !HAVE_SIGACTION */
200 switch (sig)
201 {
202 #if defined (SIGTSTP)
203 case SIGTSTP:
204 case SIGTTOU:
205 case SIGTTIN:
206 #endif
207 #if defined (SIGQUIT)
208 case SIGQUIT:
209 #endif
210 #if defined (SIGINT)
211 case SIGINT:
212 #endif
213 {
214 #if defined (SIGTSTP)
215 if (sig == SIGTSTP)
216 old_signal_handler = &old_TSTP;
217 if (sig == SIGTTOU)
218 old_signal_handler = &old_TTOU;
219 if (sig == SIGTTIN)
220 old_signal_handler = &old_TTIN;
221 #endif /* SIGTSTP */
222 #if defined (SIGQUIT)
223 if (sig == SIGQUIT)
224 old_signal_handler = &old_QUIT;
225 #endif /* SIGQUIT */
226 #if defined (SIGINT)
227 if (sig == SIGINT)
228 old_signal_handler = &old_INT;
229 #endif /* SIGINT */
230
231 /* For stop signals, restore the terminal IO, leave the cursor
232 at the bottom of the window, and stop us. */
233 terminal_goto_xy (0, screenheight - 1);
234 terminal_clear_to_eol ();
235 fflush (stdout);
236 terminal_unprep_terminal ();
237 restore_termsig (sig, old_signal_handler);
238 UNBLOCK_SIGNAL (sig);
239 kill (getpid (), sig);
240
241 /* The program is returning now. Restore our signal handler,
242 turn on terminal handling, redraw the screen, and place the
243 cursor where it belongs. */
244 terminal_prep_terminal ();
245 set_termsig (sig, old_signal_handler);
246 /* window size might be changed while sleeping */
247 reset_info_window_sizes ();
248 }
249 break;
250
251 #if defined (SIGWINCH) || defined (SIGUSR1)
252 #ifdef SIGWINCH
253 case SIGWINCH:
254 #endif
255 #ifdef SIGUSR1
256 case SIGUSR1:
257 #endif
258 {
259 /* Turn off terminal IO, tell our parent that the window has changed,
260 then reinitialize the terminal and rebuild our windows. */
261 #ifdef SIGWINCH
262 if (sig == SIGWINCH)
263 old_signal_handler = &old_WINCH;
264 #endif
265 #ifdef SIGUSR1
266 if (sig == SIGUSR1)
267 old_signal_handler = &old_USR1;
268 #endif
269 terminal_goto_xy (0, 0);
270 fflush (stdout);
271 terminal_unprep_terminal (); /* needless? */
272 restore_termsig (sig, old_signal_handler);
273 UNBLOCK_SIGNAL (sig);
274 kill (getpid (), sig);
275
276 /* After our old signal handler returns... */
277 set_termsig (sig, old_signal_handler); /* needless? */
278 terminal_prep_terminal ();
279 reset_info_window_sizes ();
280 }
281 break;
282 #endif /* SIGWINCH || SIGUSR1 */
283 }
284 #if !defined (HAVE_SIGACTION)
285 /* at this time it is safer to perform unblock after decrement */
286 term_conf_busy--;
287 #if defined (HAVE_SIGPROCMASK) || defined (HAVE_SIGSETMASK)
288 {
289 sigset_t nvar, ovar;
290 sigemptyset (&nvar);
291 mask_termsig (&nvar);
292 sigprocmask (SIG_UNBLOCK, &nvar, &ovar);
293 }
294 #endif /* HAVE_SIGPROCMASK || HAVE_SIGSETMASK */
295 #endif /* !HAVE_SIGACTION */
296 }
297 /* vim: set sw=2 cino={1s>2sn-s^-se-s: */
298