/* signal.c - signal handling
 *	Copyright (C) 1998, 1999, 2000 Free Software Foundation, Inc.
 *
 * This file is part of GnuPG.
 *
 * GnuPG 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.
 *
 * GnuPG 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 02111-1307, USA
 */

#include <config.h>
#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>
#include <assert.h>

#include "options.h"
#include "errors.h"
#include "memory.h"
#include "util.h"
#include "main.h"
#include "ttyio.h"


static volatile int caught_fatal_sig = 0;
static volatile int caught_sigusr1 = 0;

static const char *
get_signal_name( int signum )
{
  #if defined(SYS_SIGLIST_DECLARED) && defined(NSIG)
    return (signum >= 0 && signum < NSIG) ? sys_siglist[signum] : "?";
  #else
    return "some signal";
  #endif
}


static RETSIGTYPE
got_fatal_signal( int sig )
{
    const char *s;

    if( caught_fatal_sig )
	raise( sig );
    caught_fatal_sig = 1;

    secmem_term();
    /* better don't transtale these messages */
    write(2, "\n", 1 );
    s = log_get_name(); if( s ) write(2, s, strlen(s) );
    write(2, ": ", 2 );
    s = get_signal_name(sig); write(2, s, strlen(s) );
    write(2, " caught ... exiting\n", 21 );

  #ifndef HAVE_DOSISH_SYSTEM
    {	/* reset action to default action and raise signal again */
	struct sigaction nact;
	nact.sa_handler = SIG_DFL;
	sigemptyset( &nact.sa_mask );
	nact.sa_flags = 0;
	sigaction( sig, &nact, NULL);
    }
  #endif
    raise( sig );
}


static RETSIGTYPE
got_usr_signal( int sig )
{
    caught_sigusr1 = 1;
}

#ifndef HAVE_DOSISH_SYSTEM

/** If this is a system with signals, then we check if the signal is ignored
    at the moment, then we continue to ignore it. Otherwise, we start doing
    whatever action we were just asked to do */
static void
do_sigaction( int sig, struct sigaction *nact )
{
    struct sigaction oact;

    sigaction( sig, NULL, &oact );
    if( oact.sa_handler != SIG_IGN )
	sigaction( sig, nact, NULL);
}
#endif

/** Define what actions should be taken for several types of signals */
void
init_signals()
{
  #ifndef HAVE_DOSISH_SYSTEM
  /** MS systems don't have signals */
    struct sigaction nact;

    nact.sa_handler = got_fatal_signal;
    sigemptyset( &nact.sa_mask );
    nact.sa_flags = 0;
    
    /** For each of the signals, we call do_sigaction, which will set the
	action to what we specify if the signal is not currently ignored */
    do_sigaction( SIGINT, &nact );
    do_sigaction( SIGHUP, &nact );
    do_sigaction( SIGTERM, &nact );
    do_sigaction( SIGQUIT, &nact );
    do_sigaction( SIGSEGV, &nact );
    nact.sa_handler = got_usr_signal;
    sigaction( SIGUSR1, &nact, NULL );
    nact.sa_handler = SIG_IGN;
    sigaction( SIGPIPE, &nact, NULL );
  #endif
}


void
pause_on_sigusr( int which )
{
  #ifndef HAVE_DOSISH_SYSTEM
    sigset_t mask, oldmask;

    assert( which == 1 );
    sigemptyset( &mask );
    sigaddset( &mask, SIGUSR1 );

    sigprocmask( SIG_BLOCK, &mask, &oldmask );
    while( !caught_sigusr1 )
	sigsuspend( &oldmask );
    caught_sigusr1 = 0;
    sigprocmask( SIG_UNBLOCK, &mask, NULL );
  #endif
}


static void
do_block( int block )
{
  #ifndef HAVE_DOSISH_SYSTEM
    static int is_blocked;
    static sigset_t oldmask;

    if( block ) {
	sigset_t newmask;

	if( is_blocked )
	    log_bug("signals are already blocked\n");
	sigfillset( &newmask );
	sigprocmask( SIG_BLOCK, &newmask, &oldmask );
	is_blocked = 1;
    }
    else {
	if( !is_blocked )
	    log_bug("signals are not blocked\n");
	sigprocmask( SIG_SETMASK, &oldmask, NULL );
	is_blocked = 0;
    }
  #endif /*HAVE_DOSISH_SYSTEM*/
}


void
block_all_signals()
{
    do_block(1);
}

void
unblock_all_signals()
{
    do_block(0);
}