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/* signals.c -- install and maintain signal handlers.
$Id: signals.c,v 1.10 2007/07/01 21:20:31 karl Exp $
Copyright (C) 1993, 1994, 1995, 1998, 2002, 2003, 2004, 2007
Free Software Foundation, Inc.
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
Originally written by Brian Fox (bfox@ai.mit.edu). */
#include "info.h"
#include "signals.h"
void initialize_info_signal_handler (void);
/* **************************************************************** */
/* */
/* Pretending That We Have POSIX Signals */
/* */
/* **************************************************************** */
#if !defined (HAVE_SIGPROCMASK) && defined (HAVE_SIGSETMASK)
/* Perform OPERATION on NEWSET, perhaps leaving information in OLDSET. */
static void
sigprocmask (int operation, int *newset, int *oldset)
{
switch (operation)
{
case SIG_UNBLOCK:
sigsetmask (sigblock (0) & ~(*newset));
break;
case SIG_BLOCK:
*oldset = sigblock (*newset);
break;
case SIG_SETMASK:
sigsetmask (*newset);
break;
default:
abort ();
}
}
#endif /* !HAVE_SIGPROCMASK && HAVE_SIGSETMASK */
/* **************************************************************** */
/* */
/* Signal Handling for Info */
/* */
/* **************************************************************** */
#if defined (HAVE_SIGACTION) || defined (HAVE_SIGPROCMASK) ||\
defined (HAVE_SIGSETMASK)
static void
mask_termsig (sigset_t *set)
{
# if defined (SIGTSTP)
sigaddset (set, SIGTSTP);
sigaddset (set, SIGTTOU);
sigaddset (set, SIGTTIN);
# endif
# if defined (SIGWINCH)
sigaddset (set, SIGWINCH);
# endif
#if defined (SIGQUIT)
sigaddset (set, SIGQUIT);
#endif
#if defined (SIGINT)
sigaddset (set, SIGINT);
#endif
# if defined (SIGUSR1)
sigaddset (set, SIGUSR1);
# endif
}
#endif /* HAVE_SIGACTION || HAVE_SIGPROCMASK || HAVE_SIGSETMASK */
static RETSIGTYPE info_signal_proc (int sig);
#if defined (HAVE_SIGACTION)
typedef struct sigaction signal_info;
signal_info info_signal_handler;
static void
set_termsig (int sig, signal_info *old)
{
sigaction (sig, &info_signal_handler, old);
}
static void
restore_termsig (int sig, const signal_info *saved)
{
sigaction (sig, saved, NULL);
}
#else /* !HAVE_SIGACTION */
typedef RETSIGTYPE (*signal_info) ();
#define set_termsig(sig, old) (void)(*(old) = signal (sig, info_signal_proc))
#define restore_termsig(sig, saved) (void)signal (sig, *(saved))
#define info_signal_handler info_signal_proc
static int term_conf_busy = 0;
#endif /* !HAVE_SIGACTION */
static signal_info old_TSTP, old_TTOU, old_TTIN;
static signal_info old_WINCH, old_INT, old_USR1;
static signal_info old_QUIT;
void
initialize_info_signal_handler (void)
{
#ifdef SA_NOCLDSTOP
/* (Based on info from Paul Eggert found in coreutils.) Don't use
HAVE_SIGACTION to decide whether to use the sa_handler, sa_flags,
sa_mask members, as some systems (Solaris 7+) don't define them. Use
SA_NOCLDSTOP instead; it's been part of POSIX.1 since day 1 (in 1988). */
info_signal_handler.sa_handler = info_signal_proc;
info_signal_handler.sa_flags = 0;
mask_termsig (&info_signal_handler.sa_mask);
#endif /* SA_NOCLDSTOP */
#if defined (SIGTSTP)
set_termsig (SIGTSTP, &old_TSTP);
set_termsig (SIGTTOU, &old_TTOU);
set_termsig (SIGTTIN, &old_TTIN);
#endif /* SIGTSTP */
#if defined (SIGWINCH)
set_termsig (SIGWINCH, &old_WINCH);
#endif
#if defined (SIGQUIT)
set_termsig (SIGQUIT, &old_QUIT);
#endif
#if defined (SIGINT)
set_termsig (SIGINT, &old_INT);
#endif
#if defined (SIGUSR1)
/* Used by DJGPP to simulate SIGTSTP on Ctrl-Z. */
set_termsig (SIGUSR1, &old_USR1);
#endif
}
static void
redisplay_after_signal (void)
{
terminal_clear_screen ();
display_clear_display (the_display);
window_mark_chain (windows, W_UpdateWindow);
display_update_display (windows);
display_cursor_at_point (active_window);
fflush (stdout);
}
static void
reset_info_window_sizes (void)
{
terminal_goto_xy (0, 0);
fflush (stdout);
terminal_unprep_terminal ();
terminal_get_screen_size ();
terminal_prep_terminal ();
display_initialize_display (screenwidth, screenheight);
window_new_screen_size (screenwidth, screenheight);
redisplay_after_signal ();
}
static RETSIGTYPE
info_signal_proc (int sig)
{
signal_info *old_signal_handler = NULL;
#if !defined (HAVE_SIGACTION)
/* best effort: first increment this counter and later block signals */
if (term_conf_busy)
return;
term_conf_busy++;
#if defined (HAVE_SIGPROCMASK) || defined (HAVE_SIGSETMASK)
{
sigset_t nvar, ovar;
sigemptyset (&nvar);
mask_termsig (&nvar);
sigprocmask (SIG_BLOCK, &nvar, &ovar);
}
#endif /* HAVE_SIGPROCMASK || HAVE_SIGSETMASK */
#endif /* !HAVE_SIGACTION */
switch (sig)
{
#if defined (SIGTSTP)
case SIGTSTP:
case SIGTTOU:
case SIGTTIN:
#endif
#if defined (SIGQUIT)
case SIGQUIT:
#endif
#if defined (SIGINT)
case SIGINT:
#endif
{
#if defined (SIGTSTP)
if (sig == SIGTSTP)
old_signal_handler = &old_TSTP;
if (sig == SIGTTOU)
old_signal_handler = &old_TTOU;
if (sig == SIGTTIN)
old_signal_handler = &old_TTIN;
#endif /* SIGTSTP */
#if defined (SIGQUIT)
if (sig == SIGQUIT)
old_signal_handler = &old_QUIT;
#endif /* SIGQUIT */
#if defined (SIGINT)
if (sig == SIGINT)
old_signal_handler = &old_INT;
#endif /* SIGINT */
/* For stop signals, restore the terminal IO, leave the cursor
at the bottom of the window, and stop us. */
terminal_goto_xy (0, screenheight - 1);
terminal_clear_to_eol ();
fflush (stdout);
terminal_unprep_terminal ();
restore_termsig (sig, old_signal_handler);
UNBLOCK_SIGNAL (sig);
kill (getpid (), sig);
/* The program is returning now. Restore our signal handler,
turn on terminal handling, redraw the screen, and place the
cursor where it belongs. */
terminal_prep_terminal ();
set_termsig (sig, old_signal_handler);
/* window size might be changed while sleeping */
reset_info_window_sizes ();
}
break;
#if defined (SIGWINCH) || defined (SIGUSR1)
#ifdef SIGWINCH
case SIGWINCH:
#endif
#ifdef SIGUSR1
case SIGUSR1:
#endif
{
/* Turn off terminal IO, tell our parent that the window has changed,
then reinitialize the terminal and rebuild our windows. */
#ifdef SIGWINCH
if (sig == SIGWINCH)
old_signal_handler = &old_WINCH;
#endif
#ifdef SIGUSR1
if (sig == SIGUSR1)
old_signal_handler = &old_USR1;
#endif
terminal_goto_xy (0, 0);
fflush (stdout);
terminal_unprep_terminal (); /* needless? */
restore_termsig (sig, old_signal_handler);
UNBLOCK_SIGNAL (sig);
kill (getpid (), sig);
/* After our old signal handler returns... */
set_termsig (sig, old_signal_handler); /* needless? */
terminal_prep_terminal ();
reset_info_window_sizes ();
}
break;
#endif /* SIGWINCH || SIGUSR1 */
}
#if !defined (HAVE_SIGACTION)
/* at this time it is safer to perform unblock after decrement */
term_conf_busy--;
#if defined (HAVE_SIGPROCMASK) || defined (HAVE_SIGSETMASK)
{
sigset_t nvar, ovar;
sigemptyset (&nvar);
mask_termsig (&nvar);
sigprocmask (SIG_UNBLOCK, &nvar, &ovar);
}
#endif /* HAVE_SIGPROCMASK || HAVE_SIGSETMASK */
#endif /* !HAVE_SIGACTION */
}
/* vim: set sw=2 cino={1s>2sn-s^-se-s: */
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