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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  19  */
  20
  21 #include "config.h"
  22
  23 #include <signal.h>
  24 #include <stdio.h>
  25 #ifdef HAVE_SYS_POLL_H
  26 #include <sys/poll.h>
  27 #endif
  28 #include <unistd.h>
  29
  30 #include "file.h"
  31 #include "object.h"
  32 #include "process.h"
  33 #include "thread.h"
  34
  35 #if defined(linux) && defined(__SIGRTMIN)
  36 /* the signal used by linuxthreads as exit signal for clone() threads */
  37 # define SIG_PTHREAD_CANCEL (__SIGRTMIN+1)
  38 #endif
  39
  40 typedef void (*signal_callback)(void);
  41
  42 struct handler
  43 {
  44     struct object    obj;         /* object header */
  45     struct fd       *fd;          /* file descriptor for the pipe side */
  46     int              pipe_write;  /* unix fd for the pipe write side */
  47     volatile int     pending;     /* is signal pending? */
  48     signal_callback  callback;    /* callback function */
  49 };
  50
  51 static void handler_dump( struct object *obj, int verbose );
  52 static void handler_destroy( struct object *obj );
  53
  54 static const struct object_ops handler_ops =
  55 {
  56     sizeof(struct handler),   /* size */
  57     handler_dump,             /* dump */
  58     no_add_queue,             /* add_queue */
  59     NULL,                     /* remove_queue */
  60     NULL,                     /* signaled */
  61     NULL,                     /* satisfied */
  62     no_get_fd,                /* get_fd */
  63     handler_destroy           /* destroy */
  64 };
  65
  66 static void handler_poll_event( struct fd *fd, int event );
  67
  68 static const struct fd_ops handler_fd_ops =
  69 {
  70     NULL,                     /* get_poll_events */
  71     handler_poll_event,       /* poll_event */
  72     no_flush,                 /* flush */
  73     no_get_file_info,         /* get_file_info */
  74     no_queue_async            /* queue_async */
  75 };
  76
  77 static struct handler *handler_sighup;
  78 static struct handler *handler_sigterm;
  79 static struct handler *handler_sigint;
  80 static struct handler *handler_sigchld;
  81 static struct handler *handler_sigio;
  82
  83 static sigset_t blocked_sigset;
  84
  85 /* create a signal handler */
  86 static struct handler *create_handler( signal_callback callback )
  87 {
  88     struct handler *handler;
  89     int fd[2];
  90
  91     if (pipe( fd ) == -1) return NULL;
  92     if (!(handler = alloc_object( &handler_ops )))
  93     {
  94         close( fd[0] );
  95         close( fd[1] );
  96         return NULL;
  97     }
  98     handler->pipe_write = fd[1];
  99     handler->pending    = 0;
 100     handler->callback   = callback;
 101
 102     if (!(handler->fd = create_anonymous_fd( &handler_fd_ops, fd[0], &handler->obj )))
 103     {
 104         release_object( handler );
 105         return NULL;
 106     }
 107     set_fd_events( handler->fd, POLLIN );
 108     return handler;
 109 }
 110
 111 /* handle a signal received for a given handler */
 112 static void do_signal( struct handler *handler )
 113 {
 114     if (!handler->pending)
 115     {
 116         char dummy = 0;
 117         handler->pending = 1;
 118         write( handler->pipe_write, &dummy, 1 );
 119     }
 120 }
 121
 122 static void handler_dump( struct object *obj, int verbose )
 123 {
 124     struct handler *handler = (struct handler *)obj;
 125     fprintf( stderr, "Signal handler fd=%p\n", handler->fd );
 126 }
 127
 128 static void handler_destroy( struct object *obj )
 129 {
 130     struct handler *handler = (struct handler *)obj;
 131     if (handler->fd) release_object( handler->fd );
 132     close( handler->pipe_write );
 133 }
 134
 135 static void handler_poll_event( struct fd *fd, int event )
 136 {
 137     struct handler *handler = get_fd_user( fd );
 138
 139     if (event & (POLLERR | POLLHUP))
 140     {
 141         /* this is not supposed to happen */
 142         fprintf( stderr, "wineserver: Error on signal handler pipe\n" );
 143         release_object( handler );
 144     }
 145     else if (event & POLLIN)
 146     {
 147         char dummy;
 148
 149         handler->pending = 0;
 150         read( get_unix_fd( handler->fd ), &dummy, 1 );
 151         handler->callback();
 152     }
 153 }
 154
 155 /* SIGHUP callback */
 156 static void sighup_callback(void)
 157 {
 158 #ifdef DEBUG_OBJECTS
 159     dump_objects();
 160 #endif
 161 }
 162
 163 /* SIGTERM callback */
 164 static void sigterm_callback(void)
 165 {
 166     flush_registry();
 167     exit(1);
 168 }
 169
 170 /* SIGINT callback */
 171 static void sigint_callback(void)
 172 {
 173     kill_all_processes( NULL, 1 );
 174     flush_registry();
 175     exit(1);
 176 }
 177
 178 /* SIGHUP handler */
 179 static void do_sighup()
 180 {
 181     do_signal( handler_sighup );
 182 }
 183
 184 /* SIGTERM handler */
 185 static void do_sigterm()
 186 {
 187     do_signal( handler_sigterm );
 188 }
 189
 190 /* SIGINT handler */
 191 static void do_sigint()
 192 {
 193     do_signal( handler_sigint );
 194 }
 195
 196 /* SIGCHLD handler */
 197 static void do_sigchld()
 198 {
 199     do_signal( handler_sigchld );
 200 }
 201
 202 /* SIGIO handler */
 203 #ifdef HAVE_SIGINFO_T_SI_FD
 204 static void do_sigio( int signum, siginfo_t *si, void *x )
 205 {
 206     do_signal( handler_sigio );
 207     do_change_notify( si->si_fd );
 208 }
 209 #endif
 210
 211 void init_signals(void)
 212 {
 213     struct sigaction action;
 214
 215     if (!(handler_sighup  = create_handler( sighup_callback ))) goto error;
 216     if (!(handler_sigterm = create_handler( sigterm_callback ))) goto error;
 217     if (!(handler_sigint  = create_handler( sigint_callback ))) goto error;
 218     if (!(handler_sigchld = create_handler( sigchld_callback ))) goto error;
 219     if (!(handler_sigio   = create_handler( sigio_callback ))) goto error;
 220
 221     sigemptyset( &blocked_sigset );
 222     sigaddset( &blocked_sigset, SIGCHLD );
 223     sigaddset( &blocked_sigset, SIGHUP );
 224     sigaddset( &blocked_sigset, SIGINT );
 225     sigaddset( &blocked_sigset, SIGIO );
 226     sigaddset( &blocked_sigset, SIGQUIT );
 227     sigaddset( &blocked_sigset, SIGTERM );
 228 #ifdef SIG_PTHREAD_CANCEL
 229     sigaddset( &blocked_sigset, SIG_PTHREAD_CANCEL );
 230 #endif
 231
 232     action.sa_mask = blocked_sigset;
 233     action.sa_flags = 0;
 234     action.sa_handler = do_sigchld;
 235     sigaction( SIGCHLD, &action, NULL );
 236 #ifdef SIG_PTHREAD_CANCEL
 237     sigaction( SIG_PTHREAD_CANCEL, &action, NULL );
 238 #endif
 239     action.sa_handler = do_sighup;
 240     sigaction( SIGHUP, &action, NULL );
 241     action.sa_handler = do_sigint;
 242     sigaction( SIGINT, &action, NULL );
 243     action.sa_handler = do_sigterm;
 244     sigaction( SIGQUIT, &action, NULL );
 245     sigaction( SIGTERM, &action, NULL );
 246     action.sa_handler = SIG_IGN;
 247     sigaction( SIGXFSZ, &action, NULL );
 248 #ifdef HAVE_SIGINFO_T_SI_FD
 249     action.sa_sigaction = do_sigio;
 250     action.sa_flags = SA_SIGINFO;
 251     sigaction( SIGIO, &action, NULL );
 252 #endif
 253     return;
 254
 255 error:
 256     fprintf( stderr, "failed to initialize signal handlers\n" );
 257     exit(1);
 258 }
 259
 260 void close_signals(void)
 261 {
 262     sigprocmask( SIG_BLOCK, &blocked_sigset, NULL );
 263     release_object( handler_sighup );
 264     release_object( handler_sigterm );
 265     release_object( handler_sigint );
 266     release_object( handler_sigchld );
 267     release_object( handler_sigio );
 268 }