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     no_cancel_async           /* cancel_async */
  76 };
  77
  78 static struct handler *handler_sighup;
  79 static struct handler *handler_sigterm;
  80 static struct handler *handler_sigint;
  81 static struct handler *handler_sigchld;
  82 static struct handler *handler_sigio;
  83
  84 static sigset_t blocked_sigset;
  85
  86 /* create a signal handler */
  87 static struct handler *create_handler( signal_callback callback )
  88 {
  89     struct handler *handler;
  90     int fd[2];
  91
  92     if (pipe( fd ) == -1) return NULL;
  93     if (!(handler = alloc_object( &handler_ops )))
  94     {
  95         close( fd[0] );
  96         close( fd[1] );
  97         return NULL;
  98     }
  99     handler->pipe_write = fd[1];
 100     handler->pending    = 0;
 101     handler->callback   = callback;
 102
 103     if (!(handler->fd = create_anonymous_fd( &handler_fd_ops, fd[0], &handler->obj )))
 104     {
 105         release_object( handler );
 106         return NULL;
 107     }
 108     set_fd_events( handler->fd, POLLIN );
 109     return handler;
 110 }
 111
 112 /* handle a signal received for a given handler */
 113 static void do_signal( struct handler *handler )
 114 {
 115     if (!handler->pending)
 116     {
 117         char dummy = 0;
 118         handler->pending = 1;
 119         write( handler->pipe_write, &dummy, 1 );
 120     }
 121 }
 122
 123 static void handler_dump( struct object *obj, int verbose )
 124 {
 125     struct handler *handler = (struct handler *)obj;
 126     fprintf( stderr, "Signal handler fd=%p\n", handler->fd );
 127 }
 128
 129 static void handler_destroy( struct object *obj )
 130 {
 131     struct handler *handler = (struct handler *)obj;
 132     if (handler->fd) release_object( handler->fd );
 133     close( handler->pipe_write );
 134 }
 135
 136 static void handler_poll_event( struct fd *fd, int event )
 137 {
 138     struct handler *handler = get_fd_user( fd );
 139
 140     if (event & (POLLERR | POLLHUP))
 141     {
 142         /* this is not supposed to happen */
 143         fprintf( stderr, "wineserver: Error on signal handler pipe\n" );
 144         release_object( handler );
 145     }
 146     else if (event & POLLIN)
 147     {
 148         char dummy;
 149
 150         handler->pending = 0;
 151         read( get_unix_fd( handler->fd ), &dummy, 1 );
 152         handler->callback();
 153     }
 154 }
 155
 156 /* SIGHUP callback */
 157 static void sighup_callback(void)
 158 {
 159 #ifdef DEBUG_OBJECTS
 160     dump_objects();
 161 #endif
 162 }
 163
 164 /* SIGTERM callback */
 165 static void sigterm_callback(void)
 166 {
 167     flush_registry();
 168     exit(1);
 169 }
 170
 171 /* SIGINT callback */
 172 static void sigint_callback(void)
 173 {
 174     kill_all_processes( NULL, 1 );
 175     flush_registry();
 176     exit(1);
 177 }
 178
 179 /* SIGHUP handler */
 180 static void do_sighup()
 181 {
 182     do_signal( handler_sighup );
 183 }
 184
 185 /* SIGTERM handler */
 186 static void do_sigterm()
 187 {
 188     do_signal( handler_sigterm );
 189 }
 190
 191 /* SIGINT handler */
 192 static void do_sigint()
 193 {
 194     do_signal( handler_sigint );
 195 }
 196
 197 /* SIGCHLD handler */
 198 static void do_sigchld()
 199 {
 200     do_signal( handler_sigchld );
 201 }
 202
 203 /* SIGIO handler */
 204 #ifdef HAVE_SIGINFO_T_SI_FD
 205 static void do_sigio( int signum, siginfo_t *si, void *x )
 206 {
 207     do_signal( handler_sigio );
 208     do_change_notify( si->si_fd );
 209 }
 210 #endif
 211
 212 void init_signals(void)
 213 {
 214     struct sigaction action;
 215
 216     if (!(handler_sighup  = create_handler( sighup_callback ))) goto error;
 217     if (!(handler_sigterm = create_handler( sigterm_callback ))) goto error;
 218     if (!(handler_sigint  = create_handler( sigint_callback ))) goto error;
 219     if (!(handler_sigchld = create_handler( sigchld_callback ))) goto error;
 220     if (!(handler_sigio   = create_handler( sigio_callback ))) goto error;
 221
 222     sigemptyset( &blocked_sigset );
 223     sigaddset( &blocked_sigset, SIGCHLD );
 224     sigaddset( &blocked_sigset, SIGHUP );
 225     sigaddset( &blocked_sigset, SIGINT );
 226     sigaddset( &blocked_sigset, SIGIO );
 227     sigaddset( &blocked_sigset, SIGQUIT );
 228     sigaddset( &blocked_sigset, SIGTERM );
 229 #ifdef SIG_PTHREAD_CANCEL
 230     sigaddset( &blocked_sigset, SIG_PTHREAD_CANCEL );
 231 #endif
 232
 233     action.sa_mask = blocked_sigset;
 234     action.sa_flags = 0;
 235     action.sa_handler = do_sigchld;
 236     sigaction( SIGCHLD, &action, NULL );
 237 #ifdef SIG_PTHREAD_CANCEL
 238     sigaction( SIG_PTHREAD_CANCEL, &action, NULL );
 239 #endif
 240     action.sa_handler = do_sighup;
 241     sigaction( SIGHUP, &action, NULL );
 242     action.sa_handler = do_sigint;
 243     sigaction( SIGINT, &action, NULL );
 244     action.sa_handler = do_sigterm;
 245     sigaction( SIGQUIT, &action, NULL );
 246     sigaction( SIGTERM, &action, NULL );
 247     action.sa_handler = SIG_IGN;
 248     sigaction( SIGXFSZ, &action, NULL );
 249 #ifdef HAVE_SIGINFO_T_SI_FD
 250     action.sa_sigaction = do_sigio;
 251     action.sa_flags = SA_SIGINFO;
 252     sigaction( SIGIO, &action, NULL );
 253 #endif
 254     return;
 255
 256 error:
 257     fprintf( stderr, "failed to initialize signal handlers\n" );
 258     exit(1);
 259 }
 260
 261 void close_signals(void)
 262 {
 263     sigprocmask( SIG_BLOCK, &blocked_sigset, NULL );
 264     release_object( handler_sighup );
 265     release_object( handler_sigterm );
 266     release_object( handler_sigint );
 267     release_object( handler_sigchld );
 268     release_object( handler_sigio );
 269 }