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