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