g10/signal.c

   1 /* signal.c - signal handling
   2  * Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003, 2004,
   3  *               2005 Free Software Foundation, Inc.
   4  *
   5  * This file is part of GnuPG.
   6  *
   7  * GnuPG is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * GnuPG is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
  20  * USA.
  21  */
  22
  23 #include <config.h>
  24 #include <stdio.h>
  25 #include <stdlib.h>
  26 #include <signal.h>
  27 #include <unistd.h>
  28 #include <string.h>
  29 #include <errno.h>
  30 #include <assert.h>
  31 #ifdef HAVE_LIBREADLINE
  32 #include <readline/readline.h>
  33 #include <readline/history.h>
  34 #endif
  35
  36 #include "options.h"
  37 #include "errors.h"
  38 #include "memory.h"
  39 #include "util.h"
  40 #include "main.h"
  41 #include "ttyio.h"
  42
  43 #ifdef HAVE_DOSISH_SYSTEM
  44 void init_signals(void) {}
  45 void pause_on_sigusr(int which) {}
  46 #else
  47 static volatile int caught_fatal_sig = 0;
  48 static volatile int caught_sigusr1 = 0;
  49
  50 static void
  51 init_one_signal (int sig, RETSIGTYPE (*handler)(int), int check_ign )
  52 {
  53 #if defined(HAVE_SIGACTION) && defined(HAVE_STRUCT_SIGACTION)
  54     struct sigaction oact, nact;
  55
  56     if (check_ign) {
  57         /* we don't want to change an IGN handler */
  58         sigaction (sig, NULL, &oact );
  59         if (oact.sa_handler == SIG_IGN )
  60             return;
  61     }
  62
  63     nact.sa_handler = handler;
  64     sigemptyset (&nact.sa_mask);
  65     nact.sa_flags = 0;
  66     sigaction ( sig, &nact, NULL);
  67 #else
  68     RETSIGTYPE (*ohandler)(int);
  69
  70     ohandler = signal (sig, handler);
  71     if (check_ign && ohandler == SIG_IGN) {
  72         /* Change it back if it was already set to IGN */
  73         signal (sig, SIG_IGN);
  74     }
  75 #endif
  76 }
  77
  78 static RETSIGTYPE
  79 got_fatal_signal( int sig )
  80 {
  81     const char *s;
  82
  83     if( caught_fatal_sig )
  84         raise( sig );
  85     caught_fatal_sig = 1;
  86
  87     secmem_term();
  88
  89 #ifdef HAVE_LIBREADLINE
  90     rl_free_line_state ();
  91     rl_cleanup_after_signal ();
  92 #endif
  93
  94     /* Better don't translate these messages. */
  95     write(2, "\n", 1 );
  96     s = log_get_name(); if( s ) write(2, s, strlen(s) );
  97     write(2, ": ", 2 );
  98
  99 #if HAVE_DECL_SYS_SIGLIST && defined(NSIG)
 100     s = (sig >= 0 && sig < NSIG) ? sys_siglist[sig] : "?";
 101     write (2, s, strlen(s) );
 102 #else
 103     write (2, "signal ", 7 );
 104     if (sig < 0 || sig >=100)
 105         write (2, "?", 1);
 106     else {
 107         if (sig >= 10)
 108             write (2, "0123456789"+(sig/10), 1 );
 109         write (2, "0123456789"+(sig%10), 1 );
 110     }
 111 #endif
 112     write(2, " caught ... exiting\n", 20 );
 113
 114     /* Reset action to default action and raise signal again. */
 115     init_one_signal (sig, SIG_DFL, 0);
 116     remove_lockfiles ();
 117 #ifdef __riscos__
 118     riscos_close_fds ();
 119 #endif /* __riscos__ */
 120     raise( sig );
 121 }
 122
 123
 124 static RETSIGTYPE
 125 got_usr_signal( int sig )
 126 {
 127     caught_sigusr1 = 1;
 128 }
 129
 130
 131 void
 132 init_signals()
 133 {
 134     init_one_signal (SIGINT, got_fatal_signal, 1 );
 135     init_one_signal (SIGHUP, got_fatal_signal, 1 );
 136     init_one_signal (SIGTERM, got_fatal_signal, 1 );
 137     init_one_signal (SIGQUIT, got_fatal_signal, 1 );
 138     init_one_signal (SIGSEGV, got_fatal_signal, 1 );
 139     init_one_signal (SIGUSR1, got_usr_signal, 0 );
 140     init_one_signal (SIGPIPE, SIG_IGN, 0 );
 141 }
 142
 143
 144 void
 145 pause_on_sigusr( int which )
 146 {
 147 #if defined(HAVE_SIGPROCMASK) && defined(HAVE_SIGSET_T)
 148     sigset_t mask, oldmask;
 149
 150     assert( which == 1 );
 151     sigemptyset( &mask );
 152     sigaddset( &mask, SIGUSR1 );
 153
 154     sigprocmask( SIG_BLOCK, &mask, &oldmask );
 155     while( !caught_sigusr1 )
 156         sigsuspend( &oldmask );
 157     caught_sigusr1 = 0;
 158     sigprocmask( SIG_UNBLOCK, &mask, NULL );
 159 #else
 160      assert (which == 1);
 161      sighold (SIGUSR1);
 162      while (!caught_sigusr1)
 163          sigpause(SIGUSR1);
 164      caught_sigusr1 = 0;
 165      sigrelse(SIGUSR1);
 166 #endif /*! HAVE_SIGPROCMASK && HAVE_SIGSET_T */
 167 }
 168
 169 /* Disabled - see comment in tdbio.c:tdbio_begin_transaction() */
 170 #if 0
 171 static void
 172 do_block( int block )
 173 {
 174     static int is_blocked;
 175 #if defined(HAVE_SIGPROCMASK) && defined(HAVE_SIGSET_T)
 176     static sigset_t oldmask;
 177
 178     if( block ) {
 179         sigset_t newmask;
 180
 181         if( is_blocked )
 182             log_bug("signals are already blocked\n");
 183         sigfillset( &newmask );
 184         sigprocmask( SIG_BLOCK, &newmask, &oldmask );
 185         is_blocked = 1;
 186     }
 187     else {
 188         if( !is_blocked )
 189             log_bug("signals are not blocked\n");
 190         sigprocmask( SIG_SETMASK, &oldmask, NULL );
 191         is_blocked = 0;
 192     }
 193 #else /*! HAVE_SIGPROCMASK && HAVE_SIGSET_T */
 194
 195 #if defined(NSIG)
 196 #define SIGSMAX (NSIG)
 197 #elif defined(MAXSIG)
 198 #define SIGSMAX (MAXSIG+1)
 199 #else
 200 #error "define SIGSMAX to the number of signals on your platform plus one"
 201 #endif
 202
 203     static void (*disposition[SIGSMAX])(int);
 204     int sig;
 205
 206     if( block ) {
 207         if( is_blocked )
 208             log_bug("signals are already blocked\n");
 209         for (sig=1; sig < SIGSMAX; sig++) {
 210             disposition[sig] = sigset (sig, SIG_HOLD);
 211         }
 212         is_blocked = 1;
 213     }
 214     else {
 215         if( !is_blocked )
 216             log_bug("signals are not blocked\n");
 217         for (sig=1; sig < SIGSMAX; sig++) {
 218             sigset (sig, disposition[sig]);
 219         }
 220         is_blocked = 0;
 221     }
 222 #endif /*! HAVE_SIGPROCMASK && HAVE_SIGSET_T */
 223 }
 224
 225 void
 226 block_all_signals()
 227 {
 228     do_block(1);
 229 }
 230
 231 void
 232 unblock_all_signals()
 233 {
 234     do_block(0);
 235 }
 236 #endif
 237
 238 #endif /* !HAVE_DOSISH_SYSTEM */