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/*
* fatalsig.cc: Part of GNU CSSC.
*
*
* Copyright (C) 2000,2001 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 2 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, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111, USA.
*
*
*
* Handle fatal signals...
*
*/
#include "cssc.h"
#include "version.h"
#include "quit.h"
#include <signal.h> /* TODO: consider using sigaction(). */
static const char rcs_id[] = "CSSC $Id: fatalsig.cc,v 1.3 2001/09/29 19:39:41 james_youngman Exp $";
/* The expansion of RETSIGTYPE is automatically decided by the configure
* script; its value is define in config.h.
*/
typedef RETSIGTYPE (*sighandler)(int);
/* fatal_signals_to_trap contains a list of signals whose
* receipt is normally fatal and for which we wish to perform
* cleanup.
*/
static const int fatal_signals_to_trap[] =
{
SIGHUP, SIGINT, SIGQUIT, SIGPIPE
};
#define N_TRAPPED_SIGS (sizeof(fatal_signals_to_trap) / \
sizeof(fatal_signals_to_trap[0]))
/* In the array set_sig_handlers() we keep the initial disposition
* of the signals whose dispositions we alter, in order to
* restore them inside the signal handler.
*/
static sighandler initial_dispositions[N_TRAPPED_SIGS];
static int already_called = 0;
/* set_sig_handlers
*
* This function sets up signal handers for various fatal signals and
* remembers the original settings.
*/
static void set_sig_handlers( sighandler pfn )
{
unsigned int i;
for (i=0u; i<N_TRAPPED_SIGS; ++i)
{
int sig = fatal_signals_to_trap[i];
sighandler orighand = signal(sig, pfn);
if (SIG_ERR == orighand)
{
/* This is a nonfatal error. */
errormsg_with_errno("Failed to set signal handler for signal %d",
sig);
initial_dispositions[i] = SIG_DFL;
}
else
{
initial_dispositions[i] = orighand;
}
}
}
/* reset_sig_handlers
*
* Resets the original signal handlers for the fatal signals
* as saved in the array initial_dispositions.
*/
static void reset_sig_handlers( void )
{
unsigned int i;
for (i=0u; i; ++i)
{
int sig = fatal_signals_to_trap[i];
if (SIG_ERR == signal(sig, initial_dispositions[i]))
{
/* This is a nonfatal error. */
errormsg_with_errno("Failed to reset signal handler for signal %d",
sig);
}
}
}
/* handle_fatal_sig
*
* This is the signal handler function for fatal signals.
* It does some cleanup and exits the program.
*/
static RETSIGTYPE
handle_fatal_sig(int /* whatsig */ )
{
/* Reset the signal handler to the original setting. */
/* Also reset all the others too. This is in order to
* handle a "stuck" program in a useful way, and helps to
* ensure that the cleanup operation is itself interruptible
*/
reset_sig_handlers();
/* The cleanups will delete any existing lockfile.
* However, at the moment we do not delete an incomplete
* g-file.
*/
cleanup::run_cleanups();
/* Here, we exit with exit() rather than _exit(). Experience
* may show that that is a bad idea.
*/
exit(1);
}
void quit_on_fatal_signals (void)
{
ASSERT(already_called == 0);
set_sig_handlers(handle_fatal_sig);
already_called = 1;
}
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