server/signal.c

   1 /*
   2  * Server signal handling
   3  *
   4  * Copyright (C) 2003 Alexandre Julliard
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2.1 of the License, or (at your option) any later version.
  10  *
  11  * This library is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with this library; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
  19  */
  20
  21 #include "config.h"
  22
  23 #include <signal.h>
  24 #include <stdio.h>
  25 #include <sys/time.h>
  26 #ifdef HAVE_POLL_H
  27 #include <poll.h>
  28 #endif
  29 #ifdef HAVE_SYS_POLL_H
  30 #include <sys/poll.h>
  31 #endif
  32 #ifdef HAVE_SYS_RESOURCE_H
  33 #include <sys/resource.h>
  34 #endif
  35 #include <unistd.h>
  36
  37 #include "file.h"
  38 #include "object.h"
  39 #include "process.h"
  40 #include "thread.h"
  41
  42 #if defined(linux) && defined(__SIGRTMIN)
  43 /* the signal used by linuxthreads as exit signal for clone() threads */
  44 # define SIG_PTHREAD_CANCEL (__SIGRTMIN+1)
  45 #endif
  46
  47 typedef void (*signal_callback)(void);
  48
  49 struct handler
  50 {
  51     struct object    obj;         /* object header */
  52     struct fd       *fd;          /* file descriptor for the pipe side */
  53     int              pipe_write;  /* unix fd for the pipe write side */
  54     volatile int     pending;     /* is signal pending? */
  55     signal_callback  callback;    /* callback function */
  56 };
  57
  58 static void handler_dump( struct object *obj, int verbose );
  59 static void handler_destroy( struct object *obj );
  60
  61 static const struct object_ops handler_ops =
  62 {
  63     sizeof(struct handler),   /* size */
  64     handler_dump,             /* dump */
  65     no_add_queue,             /* add_queue */
  66     NULL,                     /* remove_queue */
  67     NULL,                     /* signaled */
  68     NULL,                     /* satisfied */
  69     no_signal,                /* signal */
  70     no_get_fd,                /* get_fd */
  71     no_map_access,            /* map_access */
  72     no_lookup_name,           /* lookup_name */
  73     no_close_handle,          /* close_handle */
  74     handler_destroy           /* destroy */
  75 };
  76
  77 static void handler_poll_event( struct fd *fd, int event );
  78
  79 static const struct fd_ops handler_fd_ops =
  80 {
  81     NULL,                     /* get_poll_events */
  82     handler_poll_event,       /* poll_event */
  83     no_flush,                 /* flush */
  84     no_get_file_info,         /* get_file_info */
  85     no_queue_async,           /* queue_async */
  86     no_cancel_async           /* cancel_async */
  87 };
  88
  89 static struct handler *handler_sighup;
  90 static struct handler *handler_sigterm;
  91 static struct handler *handler_sigint;
  92 static struct handler *handler_sigchld;
  93 static struct handler *handler_sigio;
  94
  95 static int watchdog;
  96
  97 /* create a signal handler */
  98 static struct handler *create_handler( signal_callback callback )
  99 {
 100     struct handler *handler;
 101     int fd[2];
 102
 103     if (pipe( fd ) == -1) return NULL;
 104     if (!(handler = alloc_object( &handler_ops )))
 105     {
 106         close( fd[0] );
 107         close( fd[1] );
 108         return NULL;
 109     }
 110     handler->pipe_write = fd[1];
 111     handler->pending    = 0;
 112     handler->callback   = callback;
 113
 114     if (!(handler->fd = create_anonymous_fd( &handler_fd_ops, fd[0], &handler->obj )))
 115     {
 116         release_object( handler );
 117         return NULL;
 118     }
 119     set_fd_events( handler->fd, POLLIN );
 120     make_object_static( &handler->obj );
 121     return handler;
 122 }
 123
 124 /* handle a signal received for a given handler */
 125 static void do_signal( struct handler *handler )
 126 {
 127     if (!handler->pending)
 128     {
 129         char dummy = 0;
 130         handler->pending = 1;
 131         write( handler->pipe_write, &dummy, 1 );
 132     }
 133 }
 134
 135 static void handler_dump( struct object *obj, int verbose )
 136 {
 137     struct handler *handler = (struct handler *)obj;
 138     fprintf( stderr, "Signal handler fd=%p\n", handler->fd );
 139 }
 140
 141 static void handler_destroy( struct object *obj )
 142 {
 143     struct handler *handler = (struct handler *)obj;
 144     if (handler->fd) release_object( handler->fd );
 145     close( handler->pipe_write );
 146 }
 147
 148 static void handler_poll_event( struct fd *fd, int event )
 149 {
 150     struct handler *handler = get_fd_user( fd );
 151
 152     if (event & (POLLERR | POLLHUP))
 153     {
 154         /* this is not supposed to happen */
 155         fprintf( stderr, "wineserver: Error on signal handler pipe\n" );
 156         release_object( handler );
 157     }
 158     else if (event & POLLIN)
 159     {
 160         char dummy;
 161
 162         handler->pending = 0;
 163         read( get_unix_fd( handler->fd ), &dummy, 1 );
 164         handler->callback();
 165     }
 166 }
 167
 168 /* SIGHUP callback */
 169 static void sighup_callback(void)
 170 {
 171 #ifdef DEBUG_OBJECTS
 172     dump_objects();
 173 #endif
 174 }
 175
 176 /* SIGTERM callback */
 177 static void sigterm_callback(void)
 178 {
 179     flush_registry();
 180     exit(1);
 181 }
 182
 183 /* SIGINT callback */
 184 static void sigint_callback(void)
 185 {
 186     kill_all_processes( NULL, 1 );
 187     flush_registry();
 188     exit(1);
 189 }
 190
 191 /* SIGHUP handler */
 192 static void do_sighup( int signum )
 193 {
 194     do_signal( handler_sighup );
 195 }
 196
 197 /* SIGTERM handler */
 198 static void do_sigterm( int signum )
 199 {
 200     do_signal( handler_sigterm );
 201 }
 202
 203 /* SIGINT handler */
 204 static void do_sigint( int signum )
 205 {
 206     do_signal( handler_sigint );
 207 }
 208
 209 /* SIGALRM handler */
 210 static void do_sigalrm( int signum )
 211 {
 212     watchdog = 1;
 213 }
 214
 215 /* SIGCHLD handler */
 216 static void do_sigchld( int signum )
 217 {
 218     do_signal( handler_sigchld );
 219 }
 220
 221 /* SIGSEGV handler */
 222 static void do_sigsegv( int signum )
 223 {
 224     fprintf( stderr, "wineserver crashed, please report this.\n");
 225     abort();
 226 }
 227
 228 /* SIGIO handler */
 229 #ifdef HAVE_SIGINFO_T_SI_FD
 230 static void do_sigio( int signum, siginfo_t *si, void *x )
 231 {
 232     do_signal( handler_sigio );
 233     do_change_notify( si->si_fd );
 234 }
 235 #endif
 236
 237 void start_watchdog(void)
 238 {
 239     alarm( 3 );
 240     watchdog = 0;
 241 }
 242
 243 void stop_watchdog(void)
 244 {
 245     alarm( 0 );
 246     watchdog = 0;
 247 }
 248
 249 int watchdog_triggered(void)
 250 {
 251     return watchdog != 0;
 252 }
 253
 254 static int core_dump_disabled( void )
 255 {
 256     int r = 0;
 257 #ifdef RLIMIT_CORE
 258     struct rlimit lim;
 259
 260     r = !getrlimit(RLIMIT_CORE, &lim) && (lim.rlim_cur == 0);
 261 #endif
 262     return r;
 263 }
 264
 265 void init_signals(void)
 266 {
 267     struct sigaction action;
 268     sigset_t blocked_sigset;
 269
 270     if (!(handler_sighup  = create_handler( sighup_callback ))) goto error;
 271     if (!(handler_sigterm = create_handler( sigterm_callback ))) goto error;
 272     if (!(handler_sigint  = create_handler( sigint_callback ))) goto error;
 273     if (!(handler_sigchld = create_handler( sigchld_callback ))) goto error;
 274     if (!(handler_sigio   = create_handler( sigio_callback ))) goto error;
 275
 276     sigemptyset( &blocked_sigset );
 277     sigaddset( &blocked_sigset, SIGCHLD );
 278     sigaddset( &blocked_sigset, SIGHUP );
 279     sigaddset( &blocked_sigset, SIGINT );
 280     sigaddset( &blocked_sigset, SIGALRM );
 281     sigaddset( &blocked_sigset, SIGIO );
 282     sigaddset( &blocked_sigset, SIGQUIT );
 283     sigaddset( &blocked_sigset, SIGTERM );
 284 #ifdef SIG_PTHREAD_CANCEL
 285     sigaddset( &blocked_sigset, SIG_PTHREAD_CANCEL );
 286 #endif
 287
 288     action.sa_mask = blocked_sigset;
 289     action.sa_flags = 0;
 290     action.sa_handler = do_sigchld;
 291     sigaction( SIGCHLD, &action, NULL );
 292 #ifdef SIG_PTHREAD_CANCEL
 293     sigaction( SIG_PTHREAD_CANCEL, &action, NULL );
 294 #endif
 295     action.sa_handler = do_sighup;
 296     sigaction( SIGHUP, &action, NULL );
 297     action.sa_handler = do_sigint;
 298     sigaction( SIGINT, &action, NULL );
 299     action.sa_handler = do_sigalrm;
 300     sigaction( SIGALRM, &action, NULL );
 301     action.sa_handler = do_sigterm;
 302     sigaction( SIGQUIT, &action, NULL );
 303     sigaction( SIGTERM, &action, NULL );
 304     if (core_dump_disabled())
 305     {
 306         action.sa_handler = do_sigsegv;
 307         sigaction( SIGSEGV, &action, NULL );
 308     }
 309     action.sa_handler = SIG_IGN;
 310     sigaction( SIGXFSZ, &action, NULL );
 311 #ifdef HAVE_SIGINFO_T_SI_FD
 312     action.sa_sigaction = do_sigio;
 313     action.sa_flags = SA_SIGINFO;
 314     sigaction( SIGIO, &action, NULL );
 315 #endif
 316     return;
 317
 318 error:
 319     fprintf( stderr, "failed to initialize signal handlers\n" );
 320     exit(1);
 321 }