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