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/*
*
* This file is part of the XForms library package.
*
* XForms is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1, or
* (at your option) any later version.
*
* XForms 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with XForms; see the file COPYING. If not, write to
* the Free Software Foundation, 59 Temple Place - Suite 330, Boston,
* MA 02111-1307, USA.
*
*/
/*
* $Id: signal.c,v 1.0 2002/05/08 05:16:30 zhao Release $
*.
* This file is part of the XForms library package.
* Copyright (c) 1996-2002 T.C. Zhao
* All rights reserved.
*.
*
*
* Simple minded quick&dirty signal handling.
*
* Only permit a specific signal to have one handler
*/
#include "forms.h"
#include <stdlib.h>
#include <signal.h>
static void
handle_signal(void)
{
FL_SIGNAL_REC *rec = fl_context->signal_rec;
for (; rec; rec = rec->next)
if (rec->expired)
{
rec->expired = 0;
rec->callback(rec->signum, rec->data);
}
}
#ifndef FL_WIN32
#define IsDangerous(s) (s == SIGBUS || s==SIGSEGV || s==SIGILL || s==SIGFPE)
#else
#define IsDangerous(s) 0
#endif
static int sig_direct;
static FL_SIGRET
default_signal_handler(int sig)
{
fl_signal_caught(sig);
/* if the signal is one of those that can cause infinite loops, handle it
and then exit */
if (IsDangerous(sig))
{
handle_signal();
fprintf(stderr, "Can't continue upon receiving signal %d\n", sig);
exit(sig);
}
#if !defined(M_XENIX) && !defined(_WIN32)
#if !defined( FL_SIGRET_IS_VOID )
return 0;
#endif
#endif
}
void
fl_add_signal_callback(int s, void (*cb) (int, void *), void *data)
{
FL_SIGNAL_REC *sig_rec, *rec = fl_context->signal_rec;
if (!fl_handle_signal)
fl_handle_signal = handle_signal;
for (; rec && rec->signum != s; rec = rec->next)
;
if (rec)
{
rec->data = data;
rec->callback = cb;
}
else
{
sig_rec = fl_calloc(1, sizeof(*sig_rec));
sig_rec->next = 0;
sig_rec->data = data;
sig_rec->callback = cb;
sig_rec->signum = s;
if (!sig_direct)
{
errno = 0;
sig_rec->ocallback = signal(s, default_signal_handler);
if (sig_rec->ocallback == (FL_OSSIG_HANDLER) - 1L || errno)
{
M_err("AddSignal", "Can't add");
fl_free(sig_rec);
return;
}
}
if (fl_context->signal_rec)
sig_rec->next = fl_context->signal_rec;
fl_context->signal_rec = sig_rec;
}
}
void
fl_remove_signal_callback(int s)
{
FL_SIGNAL_REC *last, *rec = fl_context->signal_rec;
for (last = rec; rec && rec->signum != s; last = rec, rec = rec->next)
;
if (rec)
{
if (rec == fl_context->signal_rec)
fl_context->signal_rec = rec->next;
else
last->next = rec->next;
fl_addto_freelist(rec);
if (!sig_direct)
signal(s, rec->ocallback);
}
else
{
M_err("RemoveSignalCallback", "No handler exists for signal %d", s);
}
}
void
fl_signal_caught(int s)
{
FL_SIGNAL_REC *rec = fl_context->signal_rec;
for (; rec && rec->signum != s; rec = rec->next)
;
if (rec)
{
rec->expired = 1;
if (!sig_direct && !IsDangerous(s))
signal(s, default_signal_handler);
}
else
M_err("SignalCaught", "Caught bogus signal %d", s);
}
void
fl_app_signal_direct(int y)
{
if (!fl_handle_signal)
fl_handle_signal = handle_signal;
sig_direct = y;
}
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