1 /* signals.c -- signal handling support for readline. */
2
3 /* Copyright (C) 1987, 1989, 1992 Free Software Foundation, Inc.
4
5 This file is part of the GNU Readline Library, a library for
6 reading lines of text with interactive input and history editing.
7
8 The GNU Readline Library is free software; you can redistribute it
9 and/or modify it under the terms of the GNU General Public License
10 as published by the Free Software Foundation; either version 2, or
11 (at your option) any later version.
12
13 The GNU Readline Library is distributed in the hope that it will be
14 useful, but WITHOUT ANY WARRANTY; without even the implied warranty
15 of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
17
18 The GNU General Public License is often shipped with GNU software, and
19 is generally kept in a file called COPYING or LICENSE. If you do not
20 have a copy of the license, write to the Free Software Foundation,
21 59 Temple Place, Suite 330, Boston, MA 02111 USA. */
22 #define READLINE_LIBRARY
23
24 #if defined (HAVE_CONFIG_H)
25 # include <config.h>
26 #endif
27
28 #include <stdio.h> /* Just for NULL. Yuck. */
29 #include <sys/types.h>
30 #include <signal.h>
31
32 #if defined (HAVE_UNISTD_H)
33 # include <unistd.h>
34 #endif /* HAVE_UNISTD_H */
35
36 /* System-specific feature definitions and include files. */
37 #include "rldefs.h"
38
39 #if defined (GWINSZ_IN_SYS_IOCTL)
40 # include <sys/ioctl.h>
41 #endif /* GWINSZ_IN_SYS_IOCTL */
42
43 #if defined (HANDLE_SIGNALS)
44 /* Some standard library routines. */
45 #include "readline.h"
46 #include "history.h"
47
48 #include "rlprivate.h"
49
50 #if !defined (RETSIGTYPE)
51 # if defined (VOID_SIGHANDLER)
52 # define RETSIGTYPE void
53 # else
54 # define RETSIGTYPE int
55 # endif /* !VOID_SIGHANDLER */
56 #endif /* !RETSIGTYPE */
57
58 #if defined (VOID_SIGHANDLER)
59 # define SIGHANDLER_RETURN return
60 #else
61 # define SIGHANDLER_RETURN return (0)
62 #endif
63
64 /* This typedef is equivalent to the one for Function; it allows us
65 to say SigHandler *foo = signal (SIGKILL, SIG_IGN); */
66 typedef RETSIGTYPE SigHandler ();
67
68 #if defined (HAVE_POSIX_SIGNALS)
69 typedef struct sigaction sighandler_cxt;
70 # define rl_sigaction(s, nh, oh) sigaction(s, nh, oh)
71 #else
72 typedef struct { SigHandler *sa_handler; int sa_mask, sa_flags; } sighandler_cxt;
73 # define sigemptyset(m)
74 #endif /* !HAVE_POSIX_SIGNALS */
75
76 static SigHandler *rl_set_sighandler PARAMS((int, SigHandler *, sighandler_cxt *));
77 static void rl_maybe_set_sighandler PARAMS((int, SigHandler *, sighandler_cxt *));
78
79 /* Exported variables for use by applications. */
80
81 /* If non-zero, readline will install its own signal handlers for
82 SIGINT, SIGTERM, SIGQUIT, SIGALRM, SIGTSTP, SIGTTIN, and SIGTTOU. */
83 int rl_catch_signals = 1;
84
85 /* If non-zero, readline will install a signal handler for SIGWINCH. */
86 #ifdef SIGWINCH
87 int rl_catch_sigwinch = 1;
88 #endif
89
90 static int signals_set_flag;
91 static int sigwinch_set_flag;
92
93 /* **************************************************************** */
94 /* */
95 /* Signal Handling */
96 /* */
97 /* **************************************************************** */
98
99 static sighandler_cxt old_int, old_term, old_alrm, old_quit;
100 #if defined (SIGTSTP)
101 static sighandler_cxt old_tstp, old_ttou, old_ttin;
102 #endif
103 #if defined (SIGWINCH)
104 static sighandler_cxt old_winch;
105 #endif
106
107 /* Readline signal handler functions. */
108
109 static RETSIGTYPE
rl_signal_handler(sig)110 rl_signal_handler (sig)
111 int sig;
112 {
113 #if defined (HAVE_POSIX_SIGNALS)
114 sigset_t set;
115 #else /* !HAVE_POSIX_SIGNALS */
116 # if defined (HAVE_BSD_SIGNALS)
117 long omask;
118 # else /* !HAVE_BSD_SIGNALS */
119 sighandler_cxt dummy_cxt; /* needed for rl_set_sighandler call */
120 # endif /* !HAVE_BSD_SIGNALS */
121 #endif /* !HAVE_POSIX_SIGNALS */
122
123 RL_SETSTATE(RL_STATE_SIGHANDLER);
124
125 #if !defined (HAVE_BSD_SIGNALS) && !defined (HAVE_POSIX_SIGNALS)
126 /* Since the signal will not be blocked while we are in the signal
127 handler, ignore it until rl_clear_signals resets the catcher. */
128 if (sig == SIGINT || sig == SIGALRM)
129 rl_set_sighandler (sig, SIG_IGN, &dummy_cxt);
130 #endif /* !HAVE_BSD_SIGNALS && !HAVE_POSIX_SIGNALS */
131
132 switch (sig)
133 {
134 case SIGINT:
135 rl_free_line_state ();
136 /* FALLTHROUGH */
137
138 #if defined (SIGTSTP)
139 case SIGTSTP:
140 case SIGTTOU:
141 case SIGTTIN:
142 #endif /* SIGTSTP */
143 case SIGALRM:
144 case SIGTERM:
145 case SIGQUIT:
146 rl_cleanup_after_signal ();
147
148 #if defined (HAVE_POSIX_SIGNALS)
149 sigprocmask (SIG_BLOCK, (sigset_t *)NULL, &set);
150 sigdelset (&set, sig);
151 #else /* !HAVE_POSIX_SIGNALS */
152 # if defined (HAVE_BSD_SIGNALS)
153 omask = sigblock (0);
154 # endif /* HAVE_BSD_SIGNALS */
155 #endif /* !HAVE_POSIX_SIGNALS */
156
157 #if defined (__EMX__)
158 signal (sig, SIG_ACK);
159 #endif
160
161 kill (getpid (), sig);
162
163 /* Let the signal that we just sent through. */
164 #if defined (HAVE_POSIX_SIGNALS)
165 sigprocmask (SIG_SETMASK, &set, (sigset_t *)NULL);
166 #else /* !HAVE_POSIX_SIGNALS */
167 # if defined (HAVE_BSD_SIGNALS)
168 sigsetmask (omask & ~(sigmask (sig)));
169 # endif /* HAVE_BSD_SIGNALS */
170 #endif /* !HAVE_POSIX_SIGNALS */
171
172 rl_reset_after_signal ();
173 }
174
175 RL_UNSETSTATE(RL_STATE_SIGHANDLER);
176 SIGHANDLER_RETURN;
177 }
178
179 #if defined (SIGWINCH)
180 static RETSIGTYPE
rl_sigwinch_handler(sig)181 rl_sigwinch_handler (sig)
182 int sig;
183 {
184 SigHandler *oh;
185
186 #if defined (MUST_REINSTALL_SIGHANDLERS)
187 sighandler_cxt dummy_winch;
188
189 /* We don't want to change old_winch -- it holds the state of SIGWINCH
190 disposition set by the calling application. We need this state
191 because we call the application's SIGWINCH handler after updating
192 our own idea of the screen size. */
193 rl_set_sighandler (SIGWINCH, rl_sigwinch_handler, &dummy_winch);
194 #endif
195
196 RL_SETSTATE(RL_STATE_SIGHANDLER);
197 rl_resize_terminal ();
198
199 /* If another sigwinch handler has been installed, call it. */
200 oh = (SigHandler *)old_winch.sa_handler;
201 if (oh && oh != (SigHandler *)SIG_IGN && oh != (SigHandler *)SIG_DFL)
202 (*oh) (sig);
203
204 RL_UNSETSTATE(RL_STATE_SIGHANDLER);
205 SIGHANDLER_RETURN;
206 }
207 #endif /* SIGWINCH */
208
209 /* Functions to manage signal handling. */
210
211 #if !defined (HAVE_POSIX_SIGNALS)
212 static int
rl_sigaction(sig,nh,oh)213 rl_sigaction (sig, nh, oh)
214 int sig;
215 sighandler_cxt *nh, *oh;
216 {
217 oh->sa_handler = signal (sig, nh->sa_handler);
218 return 0;
219 }
220 #endif /* !HAVE_POSIX_SIGNALS */
221
222 /* Set up a readline-specific signal handler, saving the old signal
223 information in OHANDLER. Return the old signal handler, like
224 signal(). */
225 static SigHandler *
rl_set_sighandler(sig,handler,ohandler)226 rl_set_sighandler (sig, handler, ohandler)
227 int sig;
228 SigHandler *handler;
229 sighandler_cxt *ohandler;
230 {
231 sighandler_cxt old_handler;
232 #if defined (HAVE_POSIX_SIGNALS)
233 struct sigaction act;
234
235 act.sa_handler = handler;
236 act.sa_flags = 0; /* XXX - should we set SA_RESTART for SIGWINCH? */
237 sigemptyset (&act.sa_mask);
238 sigemptyset (&ohandler->sa_mask);
239 sigaction (sig, &act, &old_handler);
240 #else
241 old_handler.sa_handler = (SigHandler *)signal (sig, handler);
242 #endif /* !HAVE_POSIX_SIGNALS */
243
244 /* XXX -- assume we have memcpy */
245 /* If rl_set_signals is called twice in a row, don't set the old handler to
246 rl_signal_handler, because that would cause infinite recursion. */
247 if (handler != rl_signal_handler || old_handler.sa_handler != rl_signal_handler)
248 memcpy (ohandler, &old_handler, sizeof (sighandler_cxt));
249
250 return (ohandler->sa_handler);
251 }
252
253 static void
rl_maybe_set_sighandler(sig,handler,ohandler)254 rl_maybe_set_sighandler (sig, handler, ohandler)
255 int sig;
256 SigHandler *handler;
257 sighandler_cxt *ohandler;
258 {
259 sighandler_cxt dummy;
260 SigHandler *oh;
261
262 sigemptyset (&dummy.sa_mask);
263 oh = rl_set_sighandler (sig, handler, ohandler);
264 if (oh == (SigHandler *)SIG_IGN)
265 rl_sigaction (sig, ohandler, &dummy);
266 }
267
268 int
rl_set_signals()269 rl_set_signals ()
270 {
271 sighandler_cxt dummy;
272 SigHandler *oh;
273
274 if (rl_catch_signals && signals_set_flag == 0)
275 {
276 rl_maybe_set_sighandler (SIGINT, rl_signal_handler, &old_int);
277 rl_maybe_set_sighandler (SIGTERM, rl_signal_handler, &old_term);
278 rl_maybe_set_sighandler (SIGQUIT, rl_signal_handler, &old_quit);
279
280 oh = rl_set_sighandler (SIGALRM, rl_signal_handler, &old_alrm);
281 if (oh == (SigHandler *)SIG_IGN)
282 rl_sigaction (SIGALRM, &old_alrm, &dummy);
283 #if defined (HAVE_POSIX_SIGNALS) && defined (SA_RESTART)
284 /* If the application using readline has already installed a signal
285 handler with SA_RESTART, SIGALRM will cause reads to be restarted
286 automatically, so readline should just get out of the way. Since
287 we tested for SIG_IGN above, we can just test for SIG_DFL here. */
288 if (oh != (SigHandler *)SIG_DFL && (old_alrm.sa_flags & SA_RESTART))
289 rl_sigaction (SIGALRM, &old_alrm, &dummy);
290 #endif /* HAVE_POSIX_SIGNALS */
291
292 #if defined (SIGTSTP)
293 rl_maybe_set_sighandler (SIGTSTP, rl_signal_handler, &old_tstp);
294 #endif /* SIGTSTP */
295
296 #if defined (SIGTTOU)
297 rl_maybe_set_sighandler (SIGTTOU, rl_signal_handler, &old_ttou);
298 #endif /* SIGTTOU */
299
300 #if defined (SIGTTIN)
301 rl_maybe_set_sighandler (SIGTTIN, rl_signal_handler, &old_ttin);
302 #endif /* SIGTTIN */
303
304 signals_set_flag = 1;
305 }
306
307 #if defined (SIGWINCH)
308 if (rl_catch_sigwinch && sigwinch_set_flag == 0)
309 {
310 rl_maybe_set_sighandler (SIGWINCH, rl_sigwinch_handler, &old_winch);
311 sigwinch_set_flag = 1;
312 }
313 #endif /* SIGWINCH */
314
315 return 0;
316 }
317
318 int
rl_clear_signals()319 rl_clear_signals ()
320 {
321 sighandler_cxt dummy;
322
323 if (rl_catch_signals && signals_set_flag == 1)
324 {
325 sigemptyset (&dummy.sa_mask);
326
327 rl_sigaction (SIGINT, &old_int, &dummy);
328 rl_sigaction (SIGTERM, &old_term, &dummy);
329 rl_sigaction (SIGQUIT, &old_quit, &dummy);
330 rl_sigaction (SIGALRM, &old_alrm, &dummy);
331
332 #if defined (SIGTSTP)
333 rl_sigaction (SIGTSTP, &old_tstp, &dummy);
334 #endif /* SIGTSTP */
335
336 #if defined (SIGTTOU)
337 rl_sigaction (SIGTTOU, &old_ttou, &dummy);
338 #endif /* SIGTTOU */
339
340 #if defined (SIGTTIN)
341 rl_sigaction (SIGTTIN, &old_ttin, &dummy);
342 #endif /* SIGTTIN */
343
344 signals_set_flag = 0;
345 }
346
347 #if defined (SIGWINCH)
348 if (rl_catch_sigwinch && sigwinch_set_flag == 1)
349 {
350 sigemptyset (&dummy.sa_mask);
351 rl_sigaction (SIGWINCH, &old_winch, &dummy);
352 sigwinch_set_flag = 0;
353 }
354 #endif
355
356 return 0;
357 }
358
359 /* Clean up the terminal and readline state after catching a signal, before
360 resending it to the calling application. */
361 void
rl_cleanup_after_signal()362 rl_cleanup_after_signal ()
363 {
364 _rl_clean_up_for_exit ();
365 (*rl_deprep_term_function) ();
366 rl_clear_signals ();
367 rl_clear_pending_input ();
368 }
369
370 /* Reset the terminal and readline state after a signal handler returns. */
371 void
rl_reset_after_signal()372 rl_reset_after_signal ()
373 {
374 (*rl_prep_term_function) (_rl_meta_flag);
375 rl_set_signals ();
376 }
377
378 /* Free up the readline variable line state for the current line (undo list,
379 any partial history entry, any keyboard macros in progress, and any
380 numeric arguments in process) after catching a signal, before calling
381 rl_cleanup_after_signal(). */
382 void
rl_free_line_state()383 rl_free_line_state ()
384 {
385 register HIST_ENTRY *entry;
386
387 rl_free_undo_list ();
388
389 entry = current_history ();
390 if (entry)
391 entry->data = (char *)NULL;
392
393 _rl_kill_kbd_macro ();
394 rl_clear_message ();
395 _rl_init_argument ();
396 }
397
398 #endif /* HANDLE_SIGNALS */
399