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gnupg/common/signal.c

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/* signal.c - signal handling
* Copyright (C) 1998, 1999, 2000, 2001, 2002,
* 2005 Free Software Foundation, Inc.
*
* This file is part of GnuPG.
*
* This file is free software; you can redistribute it and/or modify
* it under the terms of either
*
* - the GNU Lesser General Public License as published by the Free
* Software Foundation; either version 3 of the License, or (at
* your option) any later version.
*
* or
*
* - 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.
*
* or both in parallel, as here.
*
* This file 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 <https://www.gnu.org/licenses/>.
*/
#include <config.h>
#include <stdio.h>
#include <stdlib.h>
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#ifdef HAVE_SIGNAL_H
# include <signal.h>
#endif
#include <unistd.h>
#include <string.h>
#include <errno.h>
#include <assert.h>
#include "util.h"
#ifndef HAVE_DOSISH_SYSTEM
static volatile int caught_fatal_sig;
static volatile int caught_sigusr1;
#endif
static void (*cleanup_fnc)(void);
#ifndef HAVE_DOSISH_SYSTEM
static void
init_one_signal (int sig, void (*handler)(int), int check_ign )
{
# ifdef HAVE_SIGACTION
struct sigaction oact, nact;
if (check_ign)
{
/* we don't want to change an IGN handler */
sigaction (sig, NULL, &oact );
if (oact.sa_handler == SIG_IGN )
return;
}
nact.sa_handler = handler;
sigemptyset (&nact.sa_mask);
nact.sa_flags = 0;
sigaction ( sig, &nact, NULL);
# else
void (*ohandler)(int);
ohandler = signal (sig, handler);
if (check_ign && ohandler == SIG_IGN)
{
/* Change it back if it was already set to IGN */
signal (sig, SIG_IGN);
}
# endif
}
#endif /*!HAVE_DOSISH_SYSTEM*/
#ifndef HAVE_DOSISH_SYSTEM
static const char *
get_signal_name( int signum )
{
/* Note that we can't use strsignal(), because it is not
reentrant. */
#if HAVE_DECL_SYS_SIGLIST && defined(NSIG)
return (signum >= 0 && signum < NSIG) ? sys_siglist[signum] : "?";
#else
return NULL;
#endif
}
#endif /*!HAVE_DOSISH_SYSTEM*/
#ifndef HAVE_DOSISH_SYSTEM
static void
got_fatal_signal (int sig)
{
const char *s;
if (caught_fatal_sig)
raise (sig);
caught_fatal_sig = 1;
if (cleanup_fnc)
cleanup_fnc ();
/* Better don't translate these messages. */
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(void)write (2, "\n", 1 );
s = log_get_prefix (NULL);
if (s)
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(void)write(2, s, strlen (s));
(void)write (2, ": signal ", 9 );
s = get_signal_name(sig);
if (s)
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(void) write (2, s, strlen(s) );
else
{
/* We are in a signal handler so we can't use any kind of printf
even not sprintf. So we use a straightforward algorithm. We
got a report that on one particular system, raising a signal
while in this handler, the parameter SIG get sclobbered and
things are messed up because we modify its value. Although
this is a bug in that system, we will protect against it. */
if (sig < 0 || sig >= 100000)
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(void)write (2, "?", 1);
else
{
int i, value, any=0;
for (value=sig,i=10000; i; i /= 10)
{
if (value >= i || ((any || i==1) && !(value/i)))
{
(void)write (2, &"0123456789"[value/i], 1);
if ((value/i))
any = 1;
value %= i;
}
}
}
}
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(void)write (2, " caught ... exiting\n", 20);
/* Reset action to default action and raise signal again */
init_one_signal (sig, SIG_DFL, 0);
/* Fixme: remove_lockfiles ();*/
#ifdef __riscos__
close_fds ();
#endif /* __riscos__ */
raise( sig );
}
#endif /*!HAVE_DOSISH_SYSTEM*/
#ifndef HAVE_DOSISH_SYSTEM
static void
got_usr_signal (int sig)
{
(void)sig;
caught_sigusr1 = 1;
}
#endif /*!HAVE_DOSISH_SYSTEM*/
void
gnupg_init_signals (int mode, void (*fast_cleanup)(void))
{
assert (!mode);
cleanup_fnc = fast_cleanup;
#ifndef HAVE_DOSISH_SYSTEM
init_one_signal (SIGINT, got_fatal_signal, 1 );
init_one_signal (SIGHUP, got_fatal_signal, 1 );
init_one_signal (SIGTERM, got_fatal_signal, 1 );
init_one_signal (SIGQUIT, got_fatal_signal, 1 );
init_one_signal (SIGSEGV, got_fatal_signal, 1 );
init_one_signal (SIGUSR1, got_usr_signal, 0 );
init_one_signal (SIGPIPE, SIG_IGN, 0 );
#endif
}
static void
do_block (int block)
{
#ifdef HAVE_DOSISH_SYSTEM
(void)block;
#else /*!HAVE_DOSISH_SYSTEM*/
static int is_blocked;
#ifdef HAVE_SIGPROCMASK
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;
}
#else /*!HAVE_SIGPROCMASK*/
static void (*disposition[MAXSIG])();
int sig;
if (block)
{
if (is_blocked)
log_bug("signals are already blocked\n");
for (sig=1; sig < MAXSIG; sig++)
{
disposition[sig] = sigset (sig, SIG_HOLD);
}
is_blocked = 1;
}
else
{
if (!is_blocked)
log_bug ("signals are not blocked\n");
for (sig=1; sig < MAXSIG; sig++) {
sigset (sig, disposition[sig]);
}
is_blocked = 0;
}
#endif /*!HAVE_SIGPROCMASK*/
#endif /*!HAVE_DOSISH_SYSTEM*/
}
void
gnupg_block_all_signals ()
{
do_block(1);
}
void
gnupg_unblock_all_signals ()
{
do_block(0);
}