source: trunk/third/readline/signals.c @ 12992

Revision 12992, 10.5 KB checked in by kcr, 26 years ago (diff)
This commit was generated by cvs2svn to compensate for changes in r12991, which included commits to RCS files with non-trunk default branches.
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[12991]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 1, 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   675 Mass Ave, Cambridge, MA 02139, 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 (__GO32__)
44#  undef HANDLE_SIGNALS
45#endif /* __GO32__ */
46
47#if defined (HANDLE_SIGNALS)
48/* Some standard library routines. */
49#include "readline.h"
50#include "history.h"
51
52#if !defined (RETSIGTYPE)
53#  if defined (VOID_SIGHANDLER)
54#    define RETSIGTYPE void
55#  else
56#    define RETSIGTYPE int
57#  endif /* !VOID_SIGHANDLER */
58#endif /* !RETSIGTYPE */
59
60#if defined (VOID_SIGHANDLER)
61#  define SIGHANDLER_RETURN return
62#else
63#  define SIGHANDLER_RETURN return (0)
64#endif
65
66/* This typedef is equivalant to the one for Function; it allows us
67   to say SigHandler *foo = signal (SIGKILL, SIG_IGN); */
68typedef RETSIGTYPE SigHandler ();
69
70extern int readline_echoing_p;
71extern int rl_pending_input;
72extern int _rl_meta_flag;
73
74extern void free_undo_list ();
75extern void _rl_get_screen_size ();
76extern void _rl_redisplay_after_sigwinch ();
77extern void _rl_clean_up_for_exit ();
78extern void _rl_kill_kbd_macro ();
79extern void _rl_init_argument ();
80extern void rl_deprep_terminal (), rl_prep_terminal ();
81
82static SigHandler *rl_set_sighandler ();
83
84/* Exported variables for use by applications. */
85
86/* If non-zero, readline will install its own signal handlers for
87   SIGINT, SIGTERM, SIGQUIT, SIGALRM, SIGTSTP, SIGTTIN, and SIGTTOU. */
88int rl_catch_signals = 1;
89
90/* If non-zero, readline will install a signal handler for SIGWINCH. */
91#ifdef SIGWINCH
92int rl_catch_sigwinch = 1;
93#endif
94
95static int signals_set_flag;
96static int sigwinch_set_flag;
97
98/* **************************************************************** */
99/*                                                                  */
100/*                         Signal Handling                          */
101/*                                                                  */
102/* **************************************************************** */
103
104#if defined (HAVE_POSIX_SIGNALS)
105typedef struct sigaction sighandler_cxt;
106#  define rl_sigaction(s, nh, oh)       sigaction(s, nh, oh)
107#else
108typedef struct { SigHandler *sa_handler; int sa_mask, sa_flags; } sighandler_cxt;
109#  define sigemptyset(m)
110#endif /* !HAVE_POSIX_SIGNALS */
111
112static sighandler_cxt old_int, old_term, old_alrm, old_quit;
113#if defined (SIGTSTP)
114static sighandler_cxt old_tstp, old_ttou, old_ttin;
115#endif
116#if defined (SIGWINCH)
117static sighandler_cxt old_winch;
118#endif
119
120/* Readline signal handler functions. */
121
122static RETSIGTYPE
123rl_signal_handler (sig)
124     int sig;
125{
126#if defined (HAVE_POSIX_SIGNALS)
127  sigset_t set;
128#else /* !HAVE_POSIX_SIGNALS */
129#  if defined (HAVE_BSD_SIGNALS)
130  long omask;
131#  else /* !HAVE_BSD_SIGNALS */
132  sighandler_cxt dummy_cxt;     /* needed for rl_set_sighandler call */
133#  endif /* !HAVE_BSD_SIGNALS */
134#endif /* !HAVE_POSIX_SIGNALS */
135
136#if !defined (HAVE_BSD_SIGNALS) && !defined (HAVE_POSIX_SIGNALS)
137  /* Since the signal will not be blocked while we are in the signal
138     handler, ignore it until rl_clear_signals resets the catcher. */
139  if (sig == SIGINT || sig == SIGALRM)
140    rl_set_sighandler (sig, SIG_IGN, &dummy_cxt);
141#endif /* !HAVE_BSD_SIGNALS && !HAVE_POSIX_SIGNALS */
142
143  switch (sig)
144    {
145    case SIGINT:
146      rl_free_line_state ();
147      /* FALLTHROUGH */
148
149#if defined (SIGTSTP)
150    case SIGTSTP:
151    case SIGTTOU:
152    case SIGTTIN:
153#endif /* SIGTSTP */
154    case SIGALRM:
155    case SIGTERM:
156    case SIGQUIT:
157      rl_cleanup_after_signal ();
158
159#if defined (HAVE_POSIX_SIGNALS)
160      sigprocmask (SIG_BLOCK, (sigset_t *)NULL, &set);
161      sigdelset (&set, sig);
162#else /* !HAVE_POSIX_SIGNALS */
163#  if defined (HAVE_BSD_SIGNALS)
164      omask = sigblock (0);
165#  endif /* HAVE_BSD_SIGNALS */
166#endif /* !HAVE_POSIX_SIGNALS */
167
168      kill (getpid (), sig);
169
170      /* Let the signal that we just sent through.  */
171#if defined (HAVE_POSIX_SIGNALS)
172      sigprocmask (SIG_SETMASK, &set, (sigset_t *)NULL);
173#else /* !HAVE_POSIX_SIGNALS */
174#  if defined (HAVE_BSD_SIGNALS)
175      sigsetmask (omask & ~(sigmask (sig)));
176#  endif /* HAVE_BSD_SIGNALS */
177#endif /* !HAVE_POSIX_SIGNALS */
178
179      rl_reset_after_signal ();
180    }
181
182  SIGHANDLER_RETURN;
183}
184
185#if defined (SIGWINCH)
186static RETSIGTYPE
187rl_sigwinch_handler (sig)
188     int sig;
189{
190  SigHandler *oh;
191
192#if defined (MUST_REINSTALL_SIGHANDLERS)
193  sighandler_cxt dummy_winch;
194
195  /* We don't want to change old_winch -- it holds the state of SIGWINCH
196     disposition set by the calling application.  We need this state
197     because we call the application's SIGWINCH handler after updating
198     our own idea of the screen size. */
199  rl_set_sighandler (SIGWINCH, rl_sigwinch_handler, &dummy_winch);
200#endif
201
202  rl_resize_terminal ();
203
204  /* If another sigwinch handler has been installed, call it. */
205  oh = (SigHandler *)old_winch.sa_handler;
206  if (oh &&  oh != (SigHandler *)SIG_IGN && oh != (SigHandler *)SIG_DFL)
207    (*oh) (sig);
208
209  SIGHANDLER_RETURN;
210}
211#endif  /* SIGWINCH */
212
213/* Functions to manage signal handling. */
214
215#if !defined (HAVE_POSIX_SIGNALS)
216static int
217rl_sigaction (sig, nh, oh)
218     int sig;
219     sighandler_cxt *nh, *oh;
220{
221  oh->sa_handler = signal (sig, nh->sa_handler);
222  return 0;
223}
224#endif /* !HAVE_POSIX_SIGNALS */
225
226/* Set up a readline-specific signal handler, saving the old signal
227   information in OHANDLER.  Return the old signal handler, like
228   signal(). */
229static SigHandler *
230rl_set_sighandler (sig, handler, ohandler)
231     int sig;
232     SigHandler *handler;
233     sighandler_cxt *ohandler;
234{
235#if defined (HAVE_POSIX_SIGNALS)
236  struct sigaction act;
237
238  act.sa_handler = handler;
239  act.sa_flags = 0;
240  sigemptyset (&act.sa_mask);
241  sigemptyset (&ohandler->sa_mask);
242  sigaction (sig, &act, ohandler);
243#else
244  ohandler->sa_handler = (SigHandler *)signal (sig, handler);
245#endif /* !HAVE_POSIX_SIGNALS */
246  return (ohandler->sa_handler);
247}
248
249static void
250rl_maybe_set_sighandler (sig, handler, ohandler)
251     int sig;
252     SigHandler *handler;
253     sighandler_cxt *ohandler;
254{
255  sighandler_cxt dummy;
256  SigHandler *oh;
257
258  sigemptyset (&dummy.sa_mask);
259  oh = rl_set_sighandler (sig, handler, ohandler);
260  if (oh == (SigHandler *)SIG_IGN)
261    rl_sigaction (sig, ohandler, &dummy);
262}
263
264int
265rl_set_signals ()
266{
267  sighandler_cxt dummy;
268  SigHandler *oh;
269
270  if (rl_catch_signals && signals_set_flag == 0)
271    {
272      rl_maybe_set_sighandler (SIGINT, rl_signal_handler, &old_int);
273      rl_maybe_set_sighandler (SIGTERM, rl_signal_handler, &old_term);
274      rl_maybe_set_sighandler (SIGQUIT, rl_signal_handler, &old_quit);
275
276      oh = rl_set_sighandler (SIGALRM, rl_signal_handler, &old_alrm);
277      if (oh == (SigHandler *)SIG_IGN)
278        rl_sigaction (SIGALRM, &old_alrm, &dummy);
279#if defined (HAVE_POSIX_SIGNALS) && defined (SA_RESTART)
280      /* If the application using readline has already installed a signal
281         handler with SA_RESTART, SIGALRM will cause reads to be restarted
282         automatically, so readline should just get out of the way.  Since
283         we tested for SIG_IGN above, we can just test for SIG_DFL here. */
284      if (oh != (SigHandler *)SIG_DFL && (old_alrm.sa_flags & SA_RESTART))
285        rl_sigaction (SIGALRM, &old_alrm, &dummy);
286#endif /* HAVE_POSIX_SIGNALS */
287
288#if defined (SIGTSTP)
289      rl_maybe_set_sighandler (SIGTSTP, rl_signal_handler, &old_tstp);
290#endif /* SIGTSTP */
291
292#if defined (SIGTTOU)
293      rl_maybe_set_sighandler (SIGTTOU, rl_signal_handler, &old_ttou);
294#endif /* SIGTTOU */
295
296#if defined (SIGTTIN)
297      rl_maybe_set_sighandler (SIGTTIN, rl_signal_handler, &old_ttin);
298#endif /* SIGTTIN */
299
300      signals_set_flag = 1;
301    }
302
303#if defined (SIGWINCH)
304  if (rl_catch_sigwinch && sigwinch_set_flag == 0)
305    {
306      rl_maybe_set_sighandler (SIGWINCH, rl_sigwinch_handler, &old_winch);
307      sigwinch_set_flag = 1;
308    }
309#endif /* SIGWINCH */
310
311  return 0;
312}
313
314int
315rl_clear_signals ()
316{
317  sighandler_cxt dummy;
318
319  if (rl_catch_signals && signals_set_flag == 1)
320    {
321      sigemptyset (&dummy.sa_mask);
322
323      rl_sigaction (SIGINT, &old_int, &dummy);
324      rl_sigaction (SIGTERM, &old_term, &dummy);
325      rl_sigaction (SIGQUIT, &old_quit, &dummy);
326      rl_sigaction (SIGALRM, &old_alrm, &dummy);
327
328#if defined (SIGTSTP)
329      rl_sigaction (SIGTSTP, &old_tstp, &dummy);
330#endif /* SIGTSTP */
331
332#if defined (SIGTTOU)
333      rl_sigaction (SIGTTOU, &old_ttou, &dummy);
334#endif /* SIGTTOU */
335
336#if defined (SIGTTIN)
337      rl_sigaction (SIGTTIN, &old_ttin, &dummy);
338#endif /* SIGTTIN */
339
340      signals_set_flag = 0;
341    }
342
343#if defined (SIGWINCH)
344  if (rl_catch_sigwinch && sigwinch_set_flag == 1)
345    {
346      sigemptyset (&dummy.sa_mask);
347      rl_sigaction (SIGWINCH, &old_winch, &dummy);
348      sigwinch_set_flag = 0;
349    }
350#endif
351
352  return 0;
353}
354
355/* Clean up the terminal and readline state after catching a signal, before
356   resending it to the calling application. */
357void
358rl_cleanup_after_signal ()
359{
360  _rl_clean_up_for_exit ();
361  (*rl_deprep_term_function) ();
362  rl_clear_signals ();
363  rl_pending_input = 0;
364}
365
366/* Reset the terminal and readline state after a signal handler returns. */
367void
368rl_reset_after_signal ()
369{
370  (*rl_prep_term_function) (_rl_meta_flag);
371  rl_set_signals ();
372}
373
374/* Free up the readline variable line state for the current line (undo list,
375   any partial history entry, any keyboard macros in progress, and any
376   numeric arguments in process) after catching a signal, before calling
377   rl_cleanup_after_signal(). */
378void
379rl_free_line_state ()
380{
381  register HIST_ENTRY *entry;
382
383  free_undo_list ();
384
385  entry = current_history ();
386  if (entry)
387    entry->data = (char *)NULL;
388
389  _rl_kill_kbd_macro ();
390  rl_clear_message ();
391  _rl_init_argument ();
392}
393
394#endif  /* HANDLE_SIGNALS */
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