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_POLL_H
  26 #include <poll.h>
  27 #endif
  28 #ifdef HAVE_SYS_POLL_H
  29 #include <sys/poll.h>
  30 #endif
  31 #include <unistd.h>
  32
  33 #include "file.h"
  34 #include "object.h"
  35 #include "process.h"
  36 #include "thread.h"
  37
  38 #if defined(linux) && defined(__SIGRTMIN)
  39 /* the signal used by linuxthreads as exit signal for clone() threads */
  40 # define SIG_PTHREAD_CANCEL (__SIGRTMIN+1)
  41 #endif
  42
  43 typedef void (*signal_callback)(void);
  44
  45 struct handler
  46 {
  47     struct object    obj;         /* object header */
  48     struct fd       *fd;          /* file descriptor for the pipe side */
  49     int              pipe_write;  /* unix fd for the pipe write side */
  50     volatile int     pending;     /* is signal pending? */
  51     signal_callback  callback;    /* callback function */
  52 };
  53
  54 static void handler_dump( struct object *obj, int verbose );
  55 static void handler_destroy( struct object *obj );
  56
  57 static const struct object_ops handler_ops =
  58 {
  59     sizeof(struct handler),   /* size */
  60     handler_dump,             /* dump */
  61     no_add_queue,             /* add_queue */
  62     NULL,                     /* remove_queue */
  63     NULL,                     /* signaled */
  64     NULL,                     /* satisfied */
  65     no_signal,                /* signal */
  66     no_get_fd,                /* get_fd */
  67     no_close_handle,          /* close_handle */
  68     handler_destroy           /* destroy */
  69 };
  70
  71 static void handler_poll_event( struct fd *fd, int event );
  72
  73 static const struct fd_ops handler_fd_ops =
  74 {
  75     NULL,                     /* get_poll_events */
  76     handler_poll_event,       /* poll_event */
  77     no_flush,                 /* flush */
  78     no_get_file_info,         /* get_file_info */
  79     no_queue_async,           /* queue_async */
  80     no_cancel_async           /* cancel_async */
  81 };
  82
  83 static struct handler *handler_sighup;
  84 static struct handler *handler_sigterm;
  85 static struct handler *handler_sigint;
  86 static struct handler *handler_sigchld;
  87 static struct handler *handler_sigio;
  88
  89 static sigset_t blocked_sigset;
  90
  91 /* create a signal handler */
  92 static struct handler *create_handler( signal_callback callback )
  93 {
  94     struct handler *handler;
  95     int fd[2];
  96
  97     if (pipe( fd ) == -1) return NULL;
  98     if (!(handler = alloc_object( &handler_ops )))
  99     {
 100         close( fd[0] );
 101         close( fd[1] );
 102         return NULL;
 103     }
 104     handler->pipe_write = fd[1];
 105     handler->pending    = 0;
 106     handler->callback   = callback;
 107
 108     if (!(handler->fd = create_anonymous_fd( &handler_fd_ops, fd[0], &handler->obj )))
 109     {
 110         release_object( handler );
 111         return NULL;
 112     }
 113     set_fd_events( handler->fd, POLLIN );
 114     return handler;
 115 }
 116
 117 /* handle a signal received for a given handler */
 118 static void do_signal( struct handler *handler )
 119 {
 120     if (!handler->pending)
 121     {
 122         char dummy = 0;
 123         handler->pending = 1;
 124         write( handler->pipe_write, &dummy, 1 );
 125     }
 126 }
 127
 128 static void handler_dump( struct object *obj, int verbose )
 129 {
 130     struct handler *handler = (struct handler *)obj;
 131     fprintf( stderr, "Signal handler fd=%p\n", handler->fd );
 132 }
 133
 134 static void handler_destroy( struct object *obj )
 135 {
 136     struct handler *handler = (struct handler *)obj;
 137     if (handler->fd) release_object( handler->fd );
 138     close( handler->pipe_write );
 139 }
 140
 141 static void handler_poll_event( struct fd *fd, int event )
 142 {
 143     struct handler *handler = get_fd_user( fd );
 144
 145     if (event & (POLLERR | POLLHUP))
 146     {
 147         /* this is not supposed to happen */
 148         fprintf( stderr, "wineserver: Error on signal handler pipe\n" );
 149         release_object( handler );
 150     }
 151     else if (event & POLLIN)
 152     {
 153         char dummy;
 154
 155         handler->pending = 0;
 156         read( get_unix_fd( handler->fd ), &dummy, 1 );
 157         handler->callback();
 158     }
 159 }
 160
 161 /* SIGHUP callback */
 162 static void sighup_callback(void)
 163 {
 164 #ifdef DEBUG_OBJECTS
 165     dump_objects();
 166 #endif
 167 }
 168
 169 /* SIGTERM callback */
 170 static void sigterm_callback(void)
 171 {
 172     flush_registry();
 173     exit(1);
 174 }
 175
 176 /* SIGINT callback */
 177 static void sigint_callback(void)
 178 {
 179     kill_all_processes( NULL, 1 );
 180     flush_registry();
 181     exit(1);
 182 }
 183
 184 /* SIGHUP handler */
 185 static void do_sighup( int signum )
 186 {
 187     do_signal( handler_sighup );
 188 }
 189
 190 /* SIGTERM handler */
 191 static void do_sigterm( int signum )
 192 {
 193     do_signal( handler_sigterm );
 194 }
 195
 196 /* SIGINT handler */
 197 static void do_sigint( int signum )
 198 {
 199     do_signal( handler_sigint );
 200 }
 201
 202 /* SIGCHLD handler */
 203 static void do_sigchld( int signum )
 204 {
 205     do_signal( handler_sigchld );
 206 }
 207
 208 /* SIGIO handler */
 209 #ifdef HAVE_SIGINFO_T_SI_FD
 210 static void do_sigio( int signum, siginfo_t *si, void *x )
 211 {
 212     do_signal( handler_sigio );
 213     do_change_notify( si->si_fd );
 214 }
 215 #endif
 216
 217 void init_signals(void)
 218 {
 219     struct sigaction action;
 220
 221     if (!(handler_sighup  = create_handler( sighup_callback ))) goto error;
 222     if (!(handler_sigterm = create_handler( sigterm_callback ))) goto error;
 223     if (!(handler_sigint  = create_handler( sigint_callback ))) goto error;
 224     if (!(handler_sigchld = create_handler( sigchld_callback ))) goto error;
 225     if (!(handler_sigio   = create_handler( sigio_callback ))) goto error;
 226
 227     sigemptyset( &blocked_sigset );
 228     sigaddset( &blocked_sigset, SIGCHLD );
 229     sigaddset( &blocked_sigset, SIGHUP );
 230     sigaddset( &blocked_sigset, SIGINT );
 231     sigaddset( &blocked_sigset, SIGIO );
 232     sigaddset( &blocked_sigset, SIGQUIT );
 233     sigaddset( &blocked_sigset, SIGTERM );
 234 #ifdef SIG_PTHREAD_CANCEL
 235     sigaddset( &blocked_sigset, SIG_PTHREAD_CANCEL );
 236 #endif
 237
 238     action.sa_mask = blocked_sigset;
 239     action.sa_flags = 0;
 240     action.sa_handler = do_sigchld;
 241     sigaction( SIGCHLD, &action, NULL );
 242 #ifdef SIG_PTHREAD_CANCEL
 243     sigaction( SIG_PTHREAD_CANCEL, &action, NULL );
 244 #endif
 245     action.sa_handler = do_sighup;
 246     sigaction( SIGHUP, &action, NULL );
 247     action.sa_handler = do_sigint;
 248     sigaction( SIGINT, &action, NULL );
 249     action.sa_handler = do_sigterm;
 250     sigaction( SIGQUIT, &action, NULL );
 251     sigaction( SIGTERM, &action, NULL );
 252     action.sa_handler = SIG_IGN;
 253     sigaction( SIGXFSZ, &action, NULL );
 254 #ifdef HAVE_SIGINFO_T_SI_FD
 255     action.sa_sigaction = do_sigio;
 256     action.sa_flags = SA_SIGINFO;
 257     sigaction( SIGIO, &action, NULL );
 258 #endif
 259     return;
 260
 261 error:
 262     fprintf( stderr, "failed to initialize signal handlers\n" );
 263     exit(1);
 264 }
 265
 266 void close_signals(void)
 267 {
 268     sigprocmask( SIG_BLOCK, &blocked_sigset, NULL );
 269     release_object( handler_sighup );
 270     release_object( handler_sigterm );
 271     release_object( handler_sigint );
 272     release_object( handler_sigchld );
 273     release_object( handler_sigio );
 274 }