1/* signals.c -- signal handling support for readline. */
2
3/* Copyright (C) 1987-2005 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 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
22#define READLINE_LIBRARY
23
24#if defined (HAVE_CONFIG_H)
25# include "config_readline.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); */
66typedef RETSIGTYPE SigHandler ();
67
68#if defined (HAVE_POSIX_SIGNALS)
69typedef struct sigaction sighandler_cxt;
70# define rl_sigaction(s, nh, oh) sigaction(s, nh, oh)
71#else
72typedef struct { SigHandler *sa_handler; int sa_mask, sa_flags; } sighandler_cxt;
73# define sigemptyset(m)
74#endif /* !HAVE_POSIX_SIGNALS */
75
76#ifndef SA_RESTART
77# define SA_RESTART 0
78#endif
79
80static SigHandler *rl_set_sighandler PARAMS((int, SigHandler *, sighandler_cxt *));
81static void rl_maybe_set_sighandler PARAMS((int, SigHandler *, sighandler_cxt *));
82
83/* Exported variables for use by applications. */
84
85/* If non-zero, readline will install its own signal handlers for
86 SIGINT, SIGTERM, SIGQUIT, SIGALRM, SIGTSTP, SIGTTIN, and SIGTTOU. */
87int rl_catch_signals = 1;
88
89/* If non-zero, readline will install a signal handler for SIGWINCH. */
90#ifdef SIGWINCH
91int rl_catch_sigwinch = 1;
92#else
93int rl_catch_sigwinch = 0; /* for the readline state struct in readline.c */
94#endif
95
96static int signals_set_flag;
97static int sigwinch_set_flag;
98
99/* **************************************************************** */
100/* */
101/* Signal Handling */
102/* */
103/* **************************************************************** */
104
105static sighandler_cxt old_int, old_term, old_alrm, old_quit;
106#if defined (SIGTSTP)
107static sighandler_cxt old_tstp, old_ttou, old_ttin;
108#endif
109#if defined (SIGWINCH)
110static sighandler_cxt old_winch;
111#endif
112
113/* Readline signal handler functions. */
114
115static RETSIGTYPE
116rl_signal_handler (sig)
117 int sig;
118{
119#if defined (HAVE_POSIX_SIGNALS)
120 sigset_t set;
121#else /* !HAVE_POSIX_SIGNALS */
122# if defined (HAVE_BSD_SIGNALS)
123 long omask;
124# else /* !HAVE_BSD_SIGNALS */
125 sighandler_cxt dummy_cxt; /* needed for rl_set_sighandler call */
126# endif /* !HAVE_BSD_SIGNALS */
127#endif /* !HAVE_POSIX_SIGNALS */
128
129 RL_SETSTATE(RL_STATE_SIGHANDLER);
130
131#if !defined (HAVE_BSD_SIGNALS) && !defined (HAVE_POSIX_SIGNALS)
132 /* Since the signal will not be blocked while we are in the signal
133 handler, ignore it until rl_clear_signals resets the catcher. */
134# if defined (SIGALRM)
135 if (sig == SIGINT || sig == SIGALRM)
136# else
137 if (sig == SIGINT)
138# endif
139 rl_set_sighandler (sig, SIG_IGN, &dummy_cxt);
140#endif /* !HAVE_BSD_SIGNALS && !HAVE_POSIX_SIGNALS */
141
142 switch (sig)
143 {
144 case SIGINT:
145 rl_free_line_state ();
146 /* FALLTHROUGH */
147
148 case SIGTERM:
149#if defined (SIGTSTP)
150 case SIGTSTP:
151 case SIGTTOU:
152 case SIGTTIN:
153#endif /* SIGTSTP */
154#if defined (SIGALRM)
155 case SIGALRM:
156#endif
157#if defined (SIGQUIT)
158 case SIGQUIT:
159#endif
160 rl_cleanup_after_signal ();
161
162#if defined (HAVE_POSIX_SIGNALS)
163 sigemptyset (&set);
164 sigprocmask (SIG_BLOCK, (sigset_t *)NULL, &set);
165 sigdelset (&set, sig);
166#else /* !HAVE_POSIX_SIGNALS */
167# if defined (HAVE_BSD_SIGNALS)
168 omask = sigblock (0);
169# endif /* HAVE_BSD_SIGNALS */
170#endif /* !HAVE_POSIX_SIGNALS */
171
172#if defined (__EMX__)
173 signal (sig, SIG_ACK);
174#endif
175
176#if defined (HAVE_KILL)
177 kill (getpid (), sig);
178#else
179 raise (sig); /* assume we have raise */
180#endif
181
182 /* Let the signal that we just sent through. */
183#if defined (HAVE_POSIX_SIGNALS)
184 sigprocmask (SIG_SETMASK, &set, (sigset_t *)NULL);
185#else /* !HAVE_POSIX_SIGNALS */
186# if defined (HAVE_BSD_SIGNALS)
187 sigsetmask (omask & ~(sigmask (sig)));
188# endif /* HAVE_BSD_SIGNALS */
189#endif /* !HAVE_POSIX_SIGNALS */
190
191 rl_reset_after_signal ();
192 }
193
194 RL_UNSETSTATE(RL_STATE_SIGHANDLER);
195 SIGHANDLER_RETURN;
196}
197
198#if defined (SIGWINCH)
199static RETSIGTYPE
200rl_sigwinch_handler (sig)
201 int sig;
202{
203 SigHandler *oh;
204
205#if defined (MUST_REINSTALL_SIGHANDLERS)
206 sighandler_cxt dummy_winch;
207
208 /* We don't want to change old_winch -- it holds the state of SIGWINCH
209 disposition set by the calling application. We need this state
210 because we call the application's SIGWINCH handler after updating
211 our own idea of the screen size. */
212 rl_set_sighandler (SIGWINCH, rl_sigwinch_handler, &dummy_winch);
213#endif
214
215 RL_SETSTATE(RL_STATE_SIGHANDLER);
216 rl_resize_terminal ();
217
218 /* If another sigwinch handler has been installed, call it. */
219 oh = (SigHandler *)old_winch.sa_handler;
220 if (oh && oh != (SigHandler *)SIG_IGN && oh != (SigHandler *)SIG_DFL)
221 (*oh) (sig);
222
223 RL_UNSETSTATE(RL_STATE_SIGHANDLER);
224 SIGHANDLER_RETURN;
225}
226#endif /* SIGWINCH */
227
228/* Functions to manage signal handling. */
229
230#if !defined (HAVE_POSIX_SIGNALS)
231static int
232rl_sigaction (sig, nh, oh)
233 int sig;
234 sighandler_cxt *nh, *oh;
235{
236 oh->sa_handler = signal (sig, nh->sa_handler);
237 return 0;
238}
239#endif /* !HAVE_POSIX_SIGNALS */
240
241/* Set up a readline-specific signal handler, saving the old signal
242 information in OHANDLER. Return the old signal handler, like
243 signal(). */
244static SigHandler *
245rl_set_sighandler (sig, handler, ohandler)
246 int sig;
247 SigHandler *handler;
248 sighandler_cxt *ohandler;
249{
250 sighandler_cxt old_handler;
251#if defined (HAVE_POSIX_SIGNALS)
252 struct sigaction act;
253
254 act.sa_handler = handler;
255 act.sa_flags = (sig == SIGWINCH) ? SA_RESTART : 0;
256 sigemptyset (&act.sa_mask);
257 sigemptyset (&ohandler->sa_mask);
258 sigaction (sig, &act, &old_handler);
259#else
260 old_handler.sa_handler = (SigHandler *)signal (sig, handler);
261#endif /* !HAVE_POSIX_SIGNALS */
262
263 /* XXX -- assume we have memcpy */
264 /* If rl_set_signals is called twice in a row, don't set the old handler to
265 rl_signal_handler, because that would cause infinite recursion. */
266 if (handler != rl_signal_handler || old_handler.sa_handler != rl_signal_handler)
267 memcpy (ohandler, &old_handler, sizeof (sighandler_cxt));
268
269 return (ohandler->sa_handler);
270}
271
272static void
273rl_maybe_set_sighandler (sig, handler, ohandler)
274 int sig;
275 SigHandler *handler;
276 sighandler_cxt *ohandler;
277{
278 sighandler_cxt dummy;
279 SigHandler *oh;
280
281 sigemptyset (&dummy.sa_mask);
282 oh = rl_set_sighandler (sig, handler, ohandler);
283 if (oh == (SigHandler *)SIG_IGN)
284 rl_sigaction (sig, ohandler, &dummy);
285}
286
287int
288rl_set_signals ()
289{
290 sighandler_cxt dummy;
291 SigHandler *oh;
292#if defined (HAVE_POSIX_SIGNALS)
293 static int sigmask_set = 0;
294 static sigset_t bset, oset;
295#endif
296
297#if defined (HAVE_POSIX_SIGNALS)
298 if (rl_catch_signals && sigmask_set == 0)
299 {
300 sigemptyset (&bset);
301
302 sigaddset (&bset, SIGINT);
303 sigaddset (&bset, SIGINT);
304#if defined (SIGQUIT)
305 sigaddset (&bset, SIGQUIT);
306#endif
307#if defined (SIGALRM)
308 sigaddset (&bset, SIGALRM);
309#endif
310#if defined (SIGTSTP)
311 sigaddset (&bset, SIGTSTP);
312#endif
313#if defined (SIGTTIN)
314 sigaddset (&bset, SIGTTIN);
315#endif
316#if defined (SIGTTOU)
317 sigaddset (&bset, SIGTTOU);
318#endif
319 sigmask_set = 1;
320 }
321#endif /* HAVE_POSIX_SIGNALS */
322
323 if (rl_catch_signals && signals_set_flag == 0)
324 {
325#if defined (HAVE_POSIX_SIGNALS)
326 sigemptyset (&oset);
327 sigprocmask (SIG_BLOCK, &bset, &oset);
328#endif
329
330 rl_maybe_set_sighandler (SIGINT, rl_signal_handler, &old_int);
331 rl_maybe_set_sighandler (SIGTERM, rl_signal_handler, &old_term);
332#if defined (SIGQUIT)
333 rl_maybe_set_sighandler (SIGQUIT, rl_signal_handler, &old_quit);
334#endif
335
336#if defined (SIGALRM)
337 oh = rl_set_sighandler (SIGALRM, rl_signal_handler, &old_alrm);
338 if (oh == (SigHandler *)SIG_IGN)
339 rl_sigaction (SIGALRM, &old_alrm, &dummy);
340#if defined (HAVE_POSIX_SIGNALS) && defined (SA_RESTART)
341 /* If the application using readline has already installed a signal
342 handler with SA_RESTART, SIGALRM will cause reads to be restarted
343 automatically, so readline should just get out of the way. Since
344 we tested for SIG_IGN above, we can just test for SIG_DFL here. */
345 if (oh != (SigHandler *)SIG_DFL && (old_alrm.sa_flags & SA_RESTART))
346 rl_sigaction (SIGALRM, &old_alrm, &dummy);
347#endif /* HAVE_POSIX_SIGNALS */
348#endif /* SIGALRM */
349
350#if defined (SIGTSTP)
351 rl_maybe_set_sighandler (SIGTSTP, rl_signal_handler, &old_tstp);
352#endif /* SIGTSTP */
353
354#if defined (SIGTTOU)
355 rl_maybe_set_sighandler (SIGTTOU, rl_signal_handler, &old_ttou);
356#endif /* SIGTTOU */
357
358#if defined (SIGTTIN)
359 rl_maybe_set_sighandler (SIGTTIN, rl_signal_handler, &old_ttin);
360#endif /* SIGTTIN */
361
362 signals_set_flag = 1;
363
364#if defined (HAVE_POSIX_SIGNALS)
365 sigprocmask (SIG_SETMASK, &oset, (sigset_t *)NULL);
366#endif
367 }
368
369#if defined (SIGWINCH)
370 if (rl_catch_sigwinch && sigwinch_set_flag == 0)
371 {
372 rl_maybe_set_sighandler (SIGWINCH, rl_sigwinch_handler, &old_winch);
373 sigwinch_set_flag = 1;
374 }
375#endif /* SIGWINCH */
376
377 return 0;
378}
379
380int
381rl_clear_signals ()
382{
383 sighandler_cxt dummy;
384
385 if (rl_catch_signals && signals_set_flag == 1)
386 {
387 sigemptyset (&dummy.sa_mask);
388
389 rl_sigaction (SIGINT, &old_int, &dummy);
390 rl_sigaction (SIGTERM, &old_term, &dummy);
391#if defined (SIGQUIT)
392 rl_sigaction (SIGQUIT, &old_quit, &dummy);
393#endif
394#if defined (SIGALRM)
395 rl_sigaction (SIGALRM, &old_alrm, &dummy);
396#endif
397
398#if defined (SIGTSTP)
399 rl_sigaction (SIGTSTP, &old_tstp, &dummy);
400#endif /* SIGTSTP */
401
402#if defined (SIGTTOU)
403 rl_sigaction (SIGTTOU, &old_ttou, &dummy);
404#endif /* SIGTTOU */
405
406#if defined (SIGTTIN)
407 rl_sigaction (SIGTTIN, &old_ttin, &dummy);
408#endif /* SIGTTIN */
409
410 signals_set_flag = 0;
411 }
412
413#if defined (SIGWINCH)
414 if (rl_catch_sigwinch && sigwinch_set_flag == 1)
415 {
416 sigemptyset (&dummy.sa_mask);
417 rl_sigaction (SIGWINCH, &old_winch, &dummy);
418 sigwinch_set_flag = 0;
419 }
420#endif
421
422 return 0;
423}
424
425/* Clean up the terminal and readline state after catching a signal, before
426 resending it to the calling application. */
427void
428rl_cleanup_after_signal ()
429{
430 _rl_clean_up_for_exit ();
431 if (rl_deprep_term_function)
432 (*rl_deprep_term_function) ();
433 rl_clear_pending_input ();
434 rl_clear_signals ();
435}
436
437/* Reset the terminal and readline state after a signal handler returns. */
438void
439rl_reset_after_signal ()
440{
441 if (rl_prep_term_function)
442 (*rl_prep_term_function) (_rl_meta_flag);
443 rl_set_signals ();
444}
445
446/* Free up the readline variable line state for the current line (undo list,
447 any partial history entry, any keyboard macros in progress, and any
448 numeric arguments in process) after catching a signal, before calling
449 rl_cleanup_after_signal(). */
450void
451rl_free_line_state ()
452{
453 register HIST_ENTRY *entry;
454
455 rl_free_undo_list ();
456
457 entry = current_history ();
458 if (entry)
459 entry->data = (char *)NULL;
460
461 _rl_kill_kbd_macro ();
462 rl_clear_message ();
463 _rl_reset_argument ();
464}
465
466#endif /* HANDLE_SIGNALS */
467