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     NULL,                     /* flush */
  86     NULL,                     /* get_fd_type */
  87     NULL,                     /* ioctl */
  88     NULL,                     /* queue_async */
  89     NULL,                     /* reselect_async */
  90     NULL                      /* cancel_async */
  91 };
  92
  93 static struct handler *handler_sighup;
  94 static struct handler *handler_sigterm;
  95 static struct handler *handler_sigint;
  96 static struct handler *handler_sigchld;
  97 static struct handler *handler_sigio;
  98
  99 static int watchdog;
 100
 101 /* create a signal handler */
 102 static struct handler *create_handler( signal_callback callback )
 103 {
 104     struct handler *handler;
 105     int fd[2];
 106
 107     if (pipe( fd ) == -1) return NULL;
 108     if (!(handler = alloc_object( &handler_ops )))
 109     {
 110         close( fd[0] );
 111         close( fd[1] );
 112         return NULL;
 113     }
 114     handler->pipe_write = fd[1];
 115     handler->pending    = 0;
 116     handler->callback   = callback;
 117
 118     if (!(handler->fd = create_anonymous_fd( &handler_fd_ops, fd[0], &handler->obj, 0 )))
 119     {
 120         release_object( handler );
 121         return NULL;
 122     }
 123     set_fd_events( handler->fd, POLLIN );
 124     make_object_static( &handler->obj );
 125     return handler;
 126 }
 127
 128 /* handle a signal received for a given handler */
 129 static void do_signal( struct handler *handler )
 130 {
 131     if (!handler->pending)
 132     {
 133         char dummy = 0;
 134         handler->pending = 1;
 135         write( handler->pipe_write, &dummy, 1 );
 136     }
 137 }
 138
 139 static void handler_dump( struct object *obj, int verbose )
 140 {
 141     struct handler *handler = (struct handler *)obj;
 142     fprintf( stderr, "Signal handler fd=%p\n", handler->fd );
 143 }
 144
 145 static void handler_destroy( struct object *obj )
 146 {
 147     struct handler *handler = (struct handler *)obj;
 148     if (handler->fd) release_object( handler->fd );
 149     close( handler->pipe_write );
 150 }
 151
 152 static void handler_poll_event( struct fd *fd, int event )
 153 {
 154     struct handler *handler = get_fd_user( fd );
 155
 156     if (event & (POLLERR | POLLHUP))
 157     {
 158         /* this is not supposed to happen */
 159         fprintf( stderr, "wineserver: Error on signal handler pipe\n" );
 160         release_object( handler );
 161     }
 162     else if (event & POLLIN)
 163     {
 164         char dummy;
 165
 166         handler->pending = 0;
 167         read( get_unix_fd( handler->fd ), &dummy, 1 );
 168         handler->callback();
 169     }
 170 }
 171
 172 /* SIGHUP callback */
 173 static void sighup_callback(void)
 174 {
 175 #ifdef DEBUG_OBJECTS
 176     dump_objects();
 177 #endif
 178 }
 179
 180 /* SIGTERM callback */
 181 static void sigterm_callback(void)
 182 {
 183     flush_registry();
 184     exit(1);
 185 }
 186
 187 /* SIGINT callback */
 188 static void sigint_callback(void)
 189 {
 190     kill_all_processes( NULL, 1 );
 191     flush_registry();
 192     shutdown_master_socket();
 193 }
 194
 195 /* SIGHUP handler */
 196 static void do_sighup( int signum )
 197 {
 198     do_signal( handler_sighup );
 199 }
 200
 201 /* SIGTERM handler */
 202 static void do_sigterm( int signum )
 203 {
 204     do_signal( handler_sigterm );
 205 }
 206
 207 /* SIGINT handler */
 208 static void do_sigint( int signum )
 209 {
 210     do_signal( handler_sigint );
 211 }
 212
 213 /* SIGALRM handler */
 214 static void do_sigalrm( int signum )
 215 {
 216     watchdog = 1;
 217 }
 218
 219 /* SIGCHLD handler */
 220 static void do_sigchld( int signum )
 221 {
 222     do_signal( handler_sigchld );
 223 }
 224
 225 /* SIGSEGV handler */
 226 static void do_sigsegv( int signum )
 227 {
 228     fprintf( stderr, "wineserver crashed, please enable coredumps (ulimit -c unlimited) and restart.\n");
 229     abort();
 230 }
 231
 232 /* SIGIO handler */
 233 #ifdef HAVE_SIGINFO_T_SI_FD
 234 static void do_sigio( int signum, siginfo_t *si, void *x )
 235 {
 236     do_signal( handler_sigio );
 237     do_change_notify( si->si_fd );
 238 }
 239 #endif
 240
 241 void start_watchdog(void)
 242 {
 243     alarm( 3 );
 244     watchdog = 0;
 245 }
 246
 247 void stop_watchdog(void)
 248 {
 249     alarm( 0 );
 250     watchdog = 0;
 251 }
 252
 253 int watchdog_triggered(void)
 254 {
 255     return watchdog != 0;
 256 }
 257
 258 static int core_dump_disabled( void )
 259 {
 260     int r = 0;
 261 #ifdef RLIMIT_CORE
 262     struct rlimit lim;
 263
 264     r = !getrlimit(RLIMIT_CORE, &lim) && (lim.rlim_cur == 0);
 265 #endif
 266     return r;
 267 }
 268
 269 void init_signals(void)
 270 {
 271     struct sigaction action;
 272     sigset_t blocked_sigset;
 273
 274     if (!(handler_sighup  = create_handler( sighup_callback ))) goto error;
 275     if (!(handler_sigterm = create_handler( sigterm_callback ))) goto error;
 276     if (!(handler_sigint  = create_handler( sigint_callback ))) goto error;
 277     if (!(handler_sigchld = create_handler( sigchld_callback ))) goto error;
 278     if (!(handler_sigio   = create_handler( sigio_callback ))) goto error;
 279
 280     sigemptyset( &blocked_sigset );
 281     sigaddset( &blocked_sigset, SIGCHLD );
 282     sigaddset( &blocked_sigset, SIGHUP );
 283     sigaddset( &blocked_sigset, SIGINT );
 284     sigaddset( &blocked_sigset, SIGALRM );
 285     sigaddset( &blocked_sigset, SIGIO );
 286     sigaddset( &blocked_sigset, SIGQUIT );
 287     sigaddset( &blocked_sigset, SIGTERM );
 288 #ifdef SIG_PTHREAD_CANCEL
 289     sigaddset( &blocked_sigset, SIG_PTHREAD_CANCEL );
 290 #endif
 291
 292     action.sa_mask = blocked_sigset;
 293     action.sa_flags = 0;
 294     action.sa_handler = do_sigchld;
 295     sigaction( SIGCHLD, &action, NULL );
 296 #ifdef SIG_PTHREAD_CANCEL
 297     sigaction( SIG_PTHREAD_CANCEL, &action, NULL );
 298 #endif
 299     action.sa_handler = do_sighup;
 300     sigaction( SIGHUP, &action, NULL );
 301     action.sa_handler = do_sigint;
 302     sigaction( SIGINT, &action, NULL );
 303     action.sa_handler = do_sigalrm;
 304     sigaction( SIGALRM, &action, NULL );
 305     action.sa_handler = do_sigterm;
 306     sigaction( SIGQUIT, &action, NULL );
 307     sigaction( SIGTERM, &action, NULL );
 308     if (core_dump_disabled())
 309     {
 310         action.sa_handler = do_sigsegv;
 311         sigaction( SIGSEGV, &action, NULL );
 312     }
 313     action.sa_handler = SIG_IGN;
 314     sigaction( SIGXFSZ, &action, NULL );
 315 #ifdef HAVE_SIGINFO_T_SI_FD
 316     action.sa_sigaction = do_sigio;
 317     action.sa_flags = SA_SIGINFO;
 318     sigaction( SIGIO, &action, NULL );
 319 #endif
 320     return;
 321
 322 error:
 323     fprintf( stderr, "failed to initialize signal handlers\n" );
 324     exit(1);
 325 }