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 #include "request.h"
  42
  43 #if defined(linux) && defined(__SIGRTMIN)
  44 /* the signal used by linuxthreads as exit signal for clone() threads */
  45 # define SIG_PTHREAD_CANCEL (__SIGRTMIN+1)
  46 #endif
  47
  48 typedef void (*signal_callback)(void);
  49
  50 struct handler
  51 {
  52     struct object    obj;         /* object header */
  53     struct fd       *fd;          /* file descriptor for the pipe side */
  54     int              pipe_write;  /* unix fd for the pipe write side */
  55     volatile int     pending;     /* is signal pending? */
  56     signal_callback  callback;    /* callback function */
  57 };
  58
  59 static void handler_dump( struct object *obj, int verbose );
  60 static void handler_destroy( struct object *obj );
  61
  62 static const struct object_ops handler_ops =
  63 {
  64     sizeof(struct handler),   /* size */
  65     handler_dump,             /* dump */
  66     no_add_queue,             /* add_queue */
  67     NULL,                     /* remove_queue */
  68     NULL,                     /* signaled */
  69     NULL,                     /* satisfied */
  70     no_signal,                /* signal */
  71     no_get_fd,                /* get_fd */
  72     no_map_access,            /* map_access */
  73     no_lookup_name,           /* lookup_name */
  74     no_open_file,             /* open_file */
  75     no_close_handle,          /* close_handle */
  76     handler_destroy           /* destroy */
  77 };
  78
  79 static void handler_poll_event( struct fd *fd, int event );
  80
  81 static const struct fd_ops handler_fd_ops =
  82 {
  83     NULL,                     /* get_poll_events */
  84     handler_poll_event,       /* poll_event */
  85     no_flush,                 /* flush */
  86     no_get_file_info,         /* get_file_info */
  87     no_queue_async,           /* queue_async */
  88     no_cancel_async           /* cancel_async */
  89 };
  90
  91 static struct handler *handler_sighup;
  92 static struct handler *handler_sigterm;
  93 static struct handler *handler_sigint;
  94 static struct handler *handler_sigchld;
  95 static struct handler *handler_sigio;
  96
  97 static int watchdog;
  98
  99 /* create a signal handler */
 100 static struct handler *create_handler( signal_callback callback )
 101 {
 102     struct handler *handler;
 103     int fd[2];
 104
 105     if (pipe( fd ) == -1) return NULL;
 106     if (!(handler = alloc_object( &handler_ops )))
 107     {
 108         close( fd[0] );
 109         close( fd[1] );
 110         return NULL;
 111     }
 112     handler->pipe_write = fd[1];
 113     handler->pending    = 0;
 114     handler->callback   = callback;
 115
 116     if (!(handler->fd = create_anonymous_fd( &handler_fd_ops, fd[0], &handler->obj )))
 117     {
 118         release_object( handler );
 119         return NULL;
 120     }
 121     set_fd_events( handler->fd, POLLIN );
 122     make_object_static( &handler->obj );
 123     return handler;
 124 }
 125
 126 /* handle a signal received for a given handler */
 127 static void do_signal( struct handler *handler )
 128 {
 129     if (!handler->pending)
 130     {
 131         char dummy = 0;
 132         handler->pending = 1;
 133         write( handler->pipe_write, &dummy, 1 );
 134     }
 135 }
 136
 137 static void handler_dump( struct object *obj, int verbose )
 138 {
 139     struct handler *handler = (struct handler *)obj;
 140     fprintf( stderr, "Signal handler fd=%p\n", handler->fd );
 141 }
 142
 143 static void handler_destroy( struct object *obj )
 144 {
 145     struct handler *handler = (struct handler *)obj;
 146     if (handler->fd) release_object( handler->fd );
 147     close( handler->pipe_write );
 148 }
 149
 150 static void handler_poll_event( struct fd *fd, int event )
 151 {
 152     struct handler *handler = get_fd_user( fd );
 153
 154     if (event & (POLLERR | POLLHUP))
 155     {
 156         /* this is not supposed to happen */
 157         fprintf( stderr, "wineserver: Error on signal handler pipe\n" );
 158         release_object( handler );
 159     }
 160     else if (event & POLLIN)
 161     {
 162         char dummy;
 163
 164         handler->pending = 0;
 165         read( get_unix_fd( handler->fd ), &dummy, 1 );
 166         handler->callback();
 167     }
 168 }
 169
 170 /* SIGHUP callback */
 171 static void sighup_callback(void)
 172 {
 173 #ifdef DEBUG_OBJECTS
 174     dump_objects();
 175 #endif
 176 }
 177
 178 /* SIGTERM callback */
 179 static void sigterm_callback(void)
 180 {
 181     flush_registry();
 182     exit(1);
 183 }
 184
 185 /* SIGINT callback */
 186 static void sigint_callback(void)
 187 {
 188     kill_all_processes( NULL, 1 );
 189     flush_registry();
 190     shutdown_master_socket();
 191 }
 192
 193 /* SIGHUP handler */
 194 static void do_sighup( int signum )
 195 {
 196     do_signal( handler_sighup );
 197 }
 198
 199 /* SIGTERM handler */
 200 static void do_sigterm( int signum )
 201 {
 202     do_signal( handler_sigterm );
 203 }
 204
 205 /* SIGINT handler */
 206 static void do_sigint( int signum )
 207 {
 208     do_signal( handler_sigint );
 209 }
 210
 211 /* SIGALRM handler */
 212 static void do_sigalrm( int signum )
 213 {
 214     watchdog = 1;
 215 }
 216
 217 /* SIGCHLD handler */
 218 static void do_sigchld( int signum )
 219 {
 220     do_signal( handler_sigchld );
 221 }
 222
 223 /* SIGSEGV handler */
 224 static void do_sigsegv( int signum )
 225 {
 226     fprintf( stderr, "wineserver crashed, please report this.\n");
 227     abort();
 228 }
 229
 230 /* SIGIO handler */
 231 #ifdef HAVE_SIGINFO_T_SI_FD
 232 static void do_sigio( int signum, siginfo_t *si, void *x )
 233 {
 234     do_signal( handler_sigio );
 235     do_change_notify( si->si_fd );
 236 }
 237 #endif
 238
 239 void start_watchdog(void)
 240 {
 241     alarm( 3 );
 242     watchdog = 0;
 243 }
 244
 245 void stop_watchdog(void)
 246 {
 247     alarm( 0 );
 248     watchdog = 0;
 249 }
 250
 251 int watchdog_triggered(void)
 252 {
 253     return watchdog != 0;
 254 }
 255
 256 static int core_dump_disabled( void )
 257 {
 258     int r = 0;
 259 #ifdef RLIMIT_CORE
 260     struct rlimit lim;
 261
 262     r = !getrlimit(RLIMIT_CORE, &lim) && (lim.rlim_cur == 0);
 263 #endif
 264     return r;
 265 }
 266
 267 void init_signals(void)
 268 {
 269     struct sigaction action;
 270     sigset_t blocked_sigset;
 271
 272     if (!(handler_sighup  = create_handler( sighup_callback ))) goto error;
 273     if (!(handler_sigterm = create_handler( sigterm_callback ))) goto error;
 274     if (!(handler_sigint  = create_handler( sigint_callback ))) goto error;
 275     if (!(handler_sigchld = create_handler( sigchld_callback ))) goto error;
 276     if (!(handler_sigio   = create_handler( sigio_callback ))) goto error;
 277
 278     sigemptyset( &blocked_sigset );
 279     sigaddset( &blocked_sigset, SIGCHLD );
 280     sigaddset( &blocked_sigset, SIGHUP );
 281     sigaddset( &blocked_sigset, SIGINT );
 282     sigaddset( &blocked_sigset, SIGALRM );
 283     sigaddset( &blocked_sigset, SIGIO );
 284     sigaddset( &blocked_sigset, SIGQUIT );
 285     sigaddset( &blocked_sigset, SIGTERM );
 286 #ifdef SIG_PTHREAD_CANCEL
 287     sigaddset( &blocked_sigset, SIG_PTHREAD_CANCEL );
 288 #endif
 289
 290     action.sa_mask = blocked_sigset;
 291     action.sa_flags = 0;
 292     action.sa_handler = do_sigchld;
 293     sigaction( SIGCHLD, &action, NULL );
 294 #ifdef SIG_PTHREAD_CANCEL
 295     sigaction( SIG_PTHREAD_CANCEL, &action, NULL );
 296 #endif
 297     action.sa_handler = do_sighup;
 298     sigaction( SIGHUP, &action, NULL );
 299     action.sa_handler = do_sigint;
 300     sigaction( SIGINT, &action, NULL );
 301     action.sa_handler = do_sigalrm;
 302     sigaction( SIGALRM, &action, NULL );
 303     action.sa_handler = do_sigterm;
 304     sigaction( SIGQUIT, &action, NULL );
 305     sigaction( SIGTERM, &action, NULL );
 306     if (core_dump_disabled())
 307     {
 308         action.sa_handler = do_sigsegv;
 309         sigaction( SIGSEGV, &action, NULL );
 310     }
 311     action.sa_handler = SIG_IGN;
 312     sigaction( SIGXFSZ, &action, NULL );
 313 #ifdef HAVE_SIGINFO_T_SI_FD
 314     action.sa_sigaction = do_sigio;
 315     action.sa_flags = SA_SIGINFO;
 316     sigaction( SIGIO, &action, NULL );
 317 #endif
 318     return;
 319
 320 error:
 321     fprintf( stderr, "failed to initialize signal handlers\n" );
 322     exit(1);
 323 }