server/request.c

   1 /*
   2  * Server-side request handling
   3  *
   4  * Copyright (C) 1998 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 #include "wine/port.h"
  23
  24 #include <assert.h>
  25 #include <errno.h>
  26 #include <fcntl.h>
  27 #include <pwd.h>
  28 #include <signal.h>
  29 #include <stdio.h>
  30 #include <stdlib.h>
  31 #include <stdarg.h>
  32 #include <string.h>
  33 #include <sys/stat.h>
  34 #include <sys/time.h>
  35 #include <sys/types.h>
  36 #ifdef HAVE_SYS_SOCKET_H
  37 # include <sys/socket.h>
  38 #endif
  39 #ifdef HAVE_SYS_WAIT_H
  40 # include <sys/wait.h>
  41 #endif
  42 #include <sys/uio.h>
  43 #include <sys/un.h>
  44 #include <unistd.h>
  45
  46 #include "winnt.h"
  47 #include "winbase.h"
  48 #include "wincon.h"
  49 #include "wine/library.h"
  50
  51 #include "handle.h"
  52 #include "thread.h"
  53 #include "process.h"
  54 #include "user.h"
  55 #define WANT_REQUEST_HANDLERS
  56 #include "request.h"
  57
  58 /* Some versions of glibc don't define this */
  59 #ifndef SCM_RIGHTS
  60 #define SCM_RIGHTS 1
  61 #endif
  62
  63 /* path names for server master Unix socket */
  64 static const char * const server_socket_name = "socket";   /* name of the socket file */
  65 static const char * const server_lock_name = "lock";       /* name of the server lock file */
  66
  67 struct master_socket
  68 {
  69     struct object        obj;         /* object header */
  70     struct timeout_user *timeout;    /* timeout on last process exit */
  71 };
  72
  73 static void master_socket_dump( struct object *obj, int verbose );
  74 static void master_socket_poll_event( struct object *obj, int event );
  75
  76 static const struct object_ops master_socket_ops =
  77 {
  78     sizeof(struct master_socket),  /* size */
  79     master_socket_dump,            /* dump */
  80     no_add_queue,                  /* add_queue */
  81     NULL,                          /* remove_queue */
  82     NULL,                          /* signaled */
  83     NULL,                          /* satisfied */
  84     NULL,                          /* get_poll_events */
  85     master_socket_poll_event,      /* poll_event */
  86     no_get_fd,                     /* get_fd */
  87     no_flush,                      /* flush */
  88     no_get_file_info,              /* get_file_info */
  89     NULL,                          /* queue_async */
  90     no_destroy                     /* destroy */
  91 };
  92
  93
  94 struct thread *current = NULL;  /* thread handling the current request */
  95 unsigned int global_error = 0;  /* global error code for when no thread is current */
  96 unsigned int server_start_ticks = 0;  /* tick count offset from server startup */
  97
  98 static struct master_socket *master_socket;  /* the master socket object */
  99
 100 /* socket communication static structures */
 101 static struct iovec myiovec;
 102 static struct msghdr msghdr;
 103 #ifndef HAVE_MSGHDR_ACCRIGHTS
 104 struct cmsg_fd
 105 {
 106     int len;   /* sizeof structure */
 107     int level; /* SOL_SOCKET */
 108     int type;  /* SCM_RIGHTS */
 109     int fd;    /* fd to pass */
 110 };
 111 static struct cmsg_fd cmsg = { sizeof(cmsg), SOL_SOCKET, SCM_RIGHTS, -1 };
 112 #endif  /* HAVE_MSGHDR_ACCRIGHTS */
 113
 114 /* complain about a protocol error and terminate the client connection */
 115 void fatal_protocol_error( struct thread *thread, const char *err, ... )
 116 {
 117     va_list args;
 118
 119     va_start( args, err );
 120     fprintf( stderr, "Protocol error:%p: ", thread );
 121     vfprintf( stderr, err, args );
 122     va_end( args );
 123     thread->exit_code = 1;
 124     kill_thread( thread, 1 );
 125 }
 126
 127 /* complain about a protocol error and terminate the client connection */
 128 void fatal_protocol_perror( struct thread *thread, const char *err, ... )
 129 {
 130     va_list args;
 131
 132     va_start( args, err );
 133     fprintf( stderr, "Protocol error:%p: ", thread );
 134     vfprintf( stderr, err, args );
 135     perror( " " );
 136     va_end( args );
 137     thread->exit_code = 1;
 138     kill_thread( thread, 1 );
 139 }
 140
 141 /* die on a fatal error */
 142 void fatal_error( const char *err, ... )
 143 {
 144     va_list args;
 145
 146     va_start( args, err );
 147     fprintf( stderr, "wineserver: " );
 148     vfprintf( stderr, err, args );
 149     va_end( args );
 150     exit(1);
 151 }
 152
 153 /* die on a fatal error */
 154 void fatal_perror( const char *err, ... )
 155 {
 156     va_list args;
 157
 158     va_start( args, err );
 159     fprintf( stderr, "wineserver: " );
 160     vfprintf( stderr, err, args );
 161     perror( " " );
 162     va_end( args );
 163     exit(1);
 164 }
 165
 166 /* allocate the reply data */
 167 void *set_reply_data_size( size_t size )
 168 {
 169     assert( size <= get_reply_max_size() );
 170     if (size && !(current->reply_data = mem_alloc( size ))) size = 0;
 171     current->reply_size = size;
 172     return current->reply_data;
 173 }
 174
 175 /* write the remaining part of the reply */
 176 void write_reply( struct thread *thread )
 177 {
 178     int ret;
 179
 180     if ((ret = write( thread->reply_fd,
 181                       (char *)thread->reply_data + thread->reply_size - thread->reply_towrite,
 182                       thread->reply_towrite )) >= 0)
 183     {
 184         if (!(thread->reply_towrite -= ret))
 185         {
 186             free( thread->reply_data );
 187             thread->reply_data = NULL;
 188             /* sent everything, can go back to waiting for requests */
 189             change_select_fd( &thread->obj, thread->request_fd, POLLIN );
 190         }
 191         return;
 192     }
 193     if (errno == EPIPE)
 194         kill_thread( thread, 0 );  /* normal death */
 195     else if (errno != EWOULDBLOCK && errno != EAGAIN)
 196         fatal_protocol_perror( thread, "reply write" );
 197 }
 198
 199 /* send a reply to the current thread */
 200 static void send_reply( union generic_reply *reply )
 201 {
 202     int ret;
 203
 204     if (!current->reply_size)
 205     {
 206         if ((ret = write( current->reply_fd, reply, sizeof(*reply) )) != sizeof(*reply)) goto error;
 207     }
 208     else
 209     {
 210         struct iovec vec[2];
 211
 212         vec[0].iov_base = (void *)reply;
 213         vec[0].iov_len  = sizeof(*reply);
 214         vec[1].iov_base = current->reply_data;
 215         vec[1].iov_len  = current->reply_size;
 216
 217         if ((ret = writev( current->reply_fd, vec, 2 )) < sizeof(*reply)) goto error;
 218
 219         if ((current->reply_towrite = current->reply_size - (ret - sizeof(*reply))))
 220         {
 221             /* couldn't write it all, wait for POLLOUT */
 222             change_select_fd( &current->obj, current->reply_fd, POLLOUT );
 223             return;
 224         }
 225     }
 226     if (current->reply_data)
 227     {
 228         free( current->reply_data );
 229         current->reply_data = NULL;
 230     }
 231     return;
 232
 233  error:
 234     if (ret >= 0)
 235         fatal_protocol_error( current, "partial write %d\n", ret );
 236     else if (errno == EPIPE)
 237         kill_thread( current, 0 );  /* normal death */
 238     else
 239         fatal_protocol_perror( current, "reply write" );
 240 }
 241
 242 /* call a request handler */
 243 static void call_req_handler( struct thread *thread )
 244 {
 245     union generic_reply reply;
 246     enum request req = thread->req.request_header.req;
 247
 248     current = thread;
 249     current->reply_size = 0;
 250     clear_error();
 251     memset( &reply, 0, sizeof(reply) );
 252
 253     if (debug_level) trace_request();
 254
 255     if (req < REQ_NB_REQUESTS)
 256     {
 257         req_handlers[req]( &current->req, &reply );
 258         if (current)
 259         {
 260             reply.reply_header.error = current->error;
 261             reply.reply_header.reply_size = current->reply_size;
 262             if (debug_level) trace_reply( req, &reply );
 263             send_reply( &reply );
 264         }
 265         current = NULL;
 266         return;
 267     }
 268     fatal_protocol_error( current, "bad request %d\n", req );
 269 }
 270
 271 /* read a request from a thread */
 272 void read_request( struct thread *thread )
 273 {
 274     int ret;
 275
 276     if (!thread->req_toread)  /* no pending request */
 277     {
 278         if ((ret = read( thread->obj.fd, &thread->req,
 279                          sizeof(thread->req) )) != sizeof(thread->req)) goto error;
 280         if (!(thread->req_toread = thread->req.request_header.request_size))
 281         {
 282             /* no data, handle request at once */
 283             call_req_handler( thread );
 284             return;
 285         }
 286         if (!(thread->req_data = malloc( thread->req_toread )))
 287             fatal_protocol_error( thread, "no memory for %d bytes request\n", thread->req_toread );
 288     }
 289
 290     /* read the variable sized data */
 291     for (;;)
 292     {
 293         ret = read( thread->obj.fd, ((char *)thread->req_data +
 294                                      thread->req.request_header.request_size - thread->req_toread),
 295                     thread->req_toread );
 296         if (ret <= 0) break;
 297         if (!(thread->req_toread -= ret))
 298         {
 299             call_req_handler( thread );
 300             free( thread->req_data );
 301             thread->req_data = NULL;
 302             return;
 303         }
 304     }
 305
 306 error:
 307     if (!ret)  /* closed pipe */
 308         kill_thread( thread, 0 );
 309     else if (ret > 0)
 310         fatal_protocol_error( thread, "partial read %d\n", ret );
 311     else if (errno != EWOULDBLOCK && errno != EAGAIN)
 312         fatal_protocol_perror( thread, "read" );
 313 }
 314
 315 /* receive a file descriptor on the process socket */
 316 int receive_fd( struct process *process )
 317 {
 318     struct send_fd data;
 319     int fd, ret;
 320
 321 #ifdef HAVE_MSGHDR_ACCRIGHTS
 322     msghdr.msg_accrightslen = sizeof(int);
 323     msghdr.msg_accrights = (void *)&fd;
 324 #else  /* HAVE_MSGHDR_ACCRIGHTS */
 325     msghdr.msg_control    = &cmsg;
 326     msghdr.msg_controllen = sizeof(cmsg);
 327     cmsg.fd = -1;
 328 #endif  /* HAVE_MSGHDR_ACCRIGHTS */
 329
 330     myiovec.iov_base = (void *)&data;
 331     myiovec.iov_len  = sizeof(data);
 332
 333     ret = recvmsg( process->obj.fd, &msghdr, 0 );
 334 #ifndef HAVE_MSGHDR_ACCRIGHTS
 335     fd = cmsg.fd;
 336 #endif
 337
 338     if (ret == sizeof(data))
 339     {
 340         struct thread *thread;
 341
 342         if (data.tid) thread = get_thread_from_id( data.tid );
 343         else thread = (struct thread *)grab_object( process->thread_list );
 344
 345         if (!thread || thread->process != process || thread->state == TERMINATED)
 346         {
 347             if (debug_level)
 348                 fprintf( stderr, "%08x: *fd* %d <- %d bad thread id\n",
 349                          (unsigned int)data.tid, data.fd, fd );
 350             close( fd );
 351         }
 352         else
 353         {
 354             if (debug_level)
 355                 fprintf( stderr, "%08x: *fd* %d <- %d\n",
 356                          (unsigned int)thread, data.fd, fd );
 357             thread_add_inflight_fd( thread, data.fd, fd );
 358         }
 359         if (thread) release_object( thread );
 360         return 0;
 361     }
 362
 363     if (ret >= 0)
 364     {
 365         if (ret > 0)
 366             fprintf( stderr, "Protocol error: process %p: partial recvmsg %d for fd\n",
 367                      process, ret );
 368         kill_process( process, NULL, 1 );
 369     }
 370     else
 371     {
 372         if (errno != EWOULDBLOCK && errno != EAGAIN)
 373         {
 374             fprintf( stderr, "Protocol error: process %p: ", process );
 375             perror( "recvmsg" );
 376             kill_process( process, NULL, 1 );
 377         }
 378     }
 379     return -1;
 380 }
 381
 382 /* send an fd to a client */
 383 int send_client_fd( struct process *process, int fd, obj_handle_t handle )
 384 {
 385     int ret;
 386
 387     if (debug_level)
 388         fprintf( stderr, "%08x: *fd* %p -> %d\n", (unsigned int)current, handle, fd );
 389
 390 #ifdef HAVE_MSGHDR_ACCRIGHTS
 391     msghdr.msg_accrightslen = sizeof(fd);
 392     msghdr.msg_accrights = (void *)&fd;
 393 #else  /* HAVE_MSGHDR_ACCRIGHTS */
 394     msghdr.msg_control    = &cmsg;
 395     msghdr.msg_controllen = sizeof(cmsg);
 396     cmsg.fd = fd;
 397 #endif  /* HAVE_MSGHDR_ACCRIGHTS */
 398
 399     myiovec.iov_base = (void *)&handle;
 400     myiovec.iov_len  = sizeof(handle);
 401
 402     ret = sendmsg( process->obj.fd, &msghdr, 0 );
 403
 404     if (ret == sizeof(handle)) return 0;
 405
 406     if (ret >= 0)
 407     {
 408         fprintf( stderr, "Protocol error: process %p: partial sendmsg %d\n", process, ret );
 409         kill_process( process, NULL, 1 );
 410     }
 411     else if (errno == EPIPE)
 412     {
 413         kill_process( process, NULL, 0 );
 414     }
 415     else
 416     {
 417         fprintf( stderr, "Protocol error: process %p: ", process );
 418         perror( "sendmsg" );
 419         kill_process( process, NULL, 1 );
 420     }
 421     return -1;
 422 }
 423
 424 /* get current tick count to return to client */
 425 unsigned int get_tick_count(void)
 426 {
 427     struct timeval t;
 428     gettimeofday( &t, NULL );
 429     return (t.tv_sec * 1000) + (t.tv_usec / 1000) - server_start_ticks;
 430 }
 431
 432 static void master_socket_dump( struct object *obj, int verbose )
 433 {
 434     struct master_socket *sock = (struct master_socket *)obj;
 435     assert( obj->ops == &master_socket_ops );
 436     fprintf( stderr, "Master socket fd=%d\n", sock->obj.fd );
 437 }
 438
 439 /* handle a socket event */
 440 static void master_socket_poll_event( struct object *obj, int event )
 441 {
 442     struct master_socket *sock = (struct master_socket *)obj;
 443     assert( obj->ops == &master_socket_ops );
 444
 445     assert( sock == master_socket );  /* there is only one master socket */
 446
 447     if (event & (POLLERR | POLLHUP))
 448     {
 449         /* this is not supposed to happen */
 450         fprintf( stderr, "wineserver: Error on master socket\n" );
 451         release_object( obj );
 452     }
 453     else if (event & POLLIN)
 454     {
 455         struct sockaddr_un dummy;
 456         int len = sizeof(dummy);
 457         int client = accept( master_socket->obj.fd, (struct sockaddr *) &dummy, &len );
 458         if (client == -1) return;
 459         if (sock->timeout)
 460         {
 461             remove_timeout_user( sock->timeout );
 462             sock->timeout = NULL;
 463         }
 464         fcntl( client, F_SETFL, O_NONBLOCK );
 465         create_process( client );
 466     }
 467 }
 468
 469 /* remove the socket upon exit */
 470 static void socket_cleanup(void)
 471 {
 472     static int do_it_once;
 473     if (!do_it_once++) unlink( server_socket_name );
 474 }
 475
 476 /* create a directory and check its permissions */
 477 static void create_dir( const char *name, struct stat *st )
 478 {
 479     if (lstat( name, st ) == -1)
 480     {
 481         if (errno != ENOENT) fatal_perror( "lstat %s", name );
 482         if (mkdir( name, 0700 ) == -1) fatal_perror( "mkdir %s", name );
 483         if (lstat( name, st ) == -1) fatal_perror( "lstat %s", name );
 484     }
 485     if (!S_ISDIR(st->st_mode)) fatal_error( "%s is not a directory\n", name );
 486     if (st->st_uid != getuid()) fatal_error( "%s is not owned by you\n", name );
 487     if (st->st_mode & 077) fatal_error( "%s must not be accessible by other users\n", name );
 488 }
 489
 490 /* create the server directory and chdir to it */
 491 static void create_server_dir(void)
 492 {
 493     char *p, *server_dir;
 494     struct stat st, st2;
 495
 496     if (!(server_dir = strdup( wine_get_server_dir() ))) fatal_error( "out of memory\n" );
 497
 498     /* first create the base directory if needed */
 499
 500     p = strrchr( server_dir, '/' );
 501     *p = 0;
 502     create_dir( server_dir, &st );
 503
 504     /* now create the server directory */
 505
 506     *p = '/';
 507     create_dir( server_dir, &st );
 508
 509     if (chdir( server_dir ) == -1) fatal_perror( "chdir %s", server_dir );
 510     if (stat( ".", &st2 ) == -1) fatal_perror( "stat %s", server_dir );
 511     if (st.st_dev != st2.st_dev || st.st_ino != st2.st_ino)
 512         fatal_error( "chdir did not end up in %s\n", server_dir );
 513
 514     free( server_dir );
 515 }
 516
 517 /* create the lock file and return its file descriptor */
 518 static int create_server_lock(void)
 519 {
 520     struct stat st;
 521     int fd;
 522
 523     if (lstat( server_lock_name, &st ) == -1)
 524     {
 525         if (errno != ENOENT)
 526             fatal_perror( "lstat %s/%s", wine_get_server_dir(), server_lock_name );
 527     }
 528     else
 529     {
 530         if (!S_ISREG(st.st_mode))
 531             fatal_error( "%s/%s is not a regular file\n", wine_get_server_dir(), server_lock_name );
 532     }
 533
 534     if ((fd = open( server_lock_name, O_CREAT|O_TRUNC|O_WRONLY, 0600 )) == -1)
 535         fatal_perror( "error creating %s/%s", wine_get_server_dir(), server_lock_name );
 536     return fd;
 537 }
 538
 539 /* wait for the server lock */
 540 int wait_for_lock(void)
 541 {
 542     int fd, r;
 543     struct flock fl;
 544
 545     create_server_dir();
 546     fd = create_server_lock();
 547
 548     fl.l_type   = F_WRLCK;
 549     fl.l_whence = SEEK_SET;
 550     fl.l_start  = 0;
 551     fl.l_len    = 1;
 552     r = fcntl( fd, F_SETLKW, &fl );
 553     close(fd);
 554
 555     return r;
 556 }
 557
 558 /* kill the wine server holding the lock */
 559 int kill_lock_owner( int sig )
 560 {
 561     int fd, i, ret = 0;
 562     pid_t pid = 0;
 563     struct flock fl;
 564
 565     create_server_dir();
 566     fd = create_server_lock();
 567
 568     for (i = 0; i < 10; i++)
 569     {
 570         fl.l_type   = F_WRLCK;
 571         fl.l_whence = SEEK_SET;
 572         fl.l_start  = 0;
 573         fl.l_len    = 1;
 574         if (fcntl( fd, F_GETLK, &fl ) == -1) goto done;
 575         if (fl.l_type != F_WRLCK) goto done;  /* the file is not locked */
 576         if (!pid)  /* first time around */
 577         {
 578             if (!(pid = fl.l_pid)) goto done;  /* shouldn't happen */
 579             if (sig == -1)
 580             {
 581                 if (kill( pid, SIGINT ) == -1) goto done;
 582                 kill( pid, SIGCONT );
 583                 ret = 1;
 584             }
 585             else  /* just send the specified signal and return */
 586             {
 587                 ret = (kill( pid, sig ) != -1);
 588                 goto done;
 589             }
 590         }
 591         else if (fl.l_pid != pid) goto done;  /* no longer the same process */
 592         sleep( 1 );
 593     }
 594     /* waited long enough, now kill it */
 595     kill( pid, SIGKILL );
 596
 597  done:
 598     close( fd );
 599     return ret;
 600 }
 601
 602 /* acquire the main server lock */
 603 static void acquire_lock(void)
 604 {
 605     struct sockaddr_un addr;
 606     struct stat st;
 607     struct flock fl;
 608     int fd, slen, got_lock = 0;
 609
 610     fd = create_server_lock();
 611
 612     fl.l_type   = F_WRLCK;
 613     fl.l_whence = SEEK_SET;
 614     fl.l_start  = 0;
 615     fl.l_len    = 1;
 616     if (fcntl( fd, F_SETLK, &fl ) != -1)
 617     {
 618         /* check for crashed server */
 619         if (stat( server_socket_name, &st ) != -1 &&   /* there is a leftover socket */
 620             stat( "core", &st ) != -1 && st.st_size)   /* and there is a non-empty core file */
 621         {
 622             fprintf( stderr,
 623                      "Warning: a previous instance of the wine server seems to have crashed.\n"
 624                      "Please run 'gdb %s %s/core',\n"
 625                      "type 'backtrace' at the gdb prompt and report the results. Thanks.\n\n",
 626                      server_argv0, wine_get_server_dir() );
 627         }
 628         unlink( server_socket_name ); /* we got the lock, we can safely remove the socket */
 629         got_lock = 1;
 630         /* in that case we reuse fd without closing it, this ensures
 631          * that we hold the lock until the process exits */
 632     }
 633     else
 634     {
 635         switch(errno)
 636         {
 637         case ENOLCK:
 638             break;
 639         case EACCES:
 640             /* check whether locks work at all on this file system */
 641             if (fcntl( fd, F_GETLK, &fl ) == -1) break;
 642             /* fall through */
 643         case EAGAIN:
 644             exit(2); /* we didn't get the lock, exit with special status */
 645         default:
 646             fatal_perror( "fcntl %s/%s", wine_get_server_dir(), server_lock_name );
 647         }
 648         /* it seems we can't use locks on this fs, so we will use the socket existence as lock */
 649         close( fd );
 650     }
 651
 652     if ((fd = socket( AF_UNIX, SOCK_STREAM, 0 )) == -1) fatal_perror( "socket" );
 653     addr.sun_family = AF_UNIX;
 654     strcpy( addr.sun_path, server_socket_name );
 655     slen = sizeof(addr) - sizeof(addr.sun_path) + strlen(addr.sun_path) + 1;
 656 #ifdef HAVE_SOCKADDR_SUN_LEN
 657     addr.sun_len = slen;
 658 #endif
 659     if (bind( fd, (struct sockaddr *)&addr, slen ) == -1)
 660     {
 661         if ((errno == EEXIST) || (errno == EADDRINUSE))
 662         {
 663             if (got_lock)
 664                 fatal_error( "couldn't bind to the socket even though we hold the lock\n" );
 665             exit(2); /* we didn't get the lock, exit with special status */
 666         }
 667         fatal_perror( "bind" );
 668     }
 669     atexit( socket_cleanup );
 670     chmod( server_socket_name, 0600 );  /* make sure no other user can connect */
 671     if (listen( fd, 5 ) == -1) fatal_perror( "listen" );
 672
 673     if (!(master_socket = alloc_object( &master_socket_ops, fd )))
 674         fatal_error( "out of memory\n" );
 675     master_socket->timeout = NULL;
 676     set_select_events( &master_socket->obj, POLLIN );
 677 }
 678
 679 /* open the master server socket and start waiting for new clients */
 680 void open_master_socket(void)
 681 {
 682     int pid, status, sync_pipe[2];
 683     char dummy;
 684
 685     /* make sure no request is larger than the maximum size */
 686     assert( sizeof(union generic_request) == sizeof(struct request_max_size) );
 687     assert( sizeof(union generic_reply) == sizeof(struct request_max_size) );
 688
 689     create_server_dir();
 690     if (pipe( sync_pipe ) == -1) fatal_perror( "pipe" );
 691
 692     pid = fork();
 693     switch( pid )
 694     {
 695     case 0:  /* child */
 696         setsid();
 697         close( sync_pipe[0] );
 698
 699         acquire_lock();
 700
 701         /* signal parent */
 702         write( sync_pipe[1], &dummy, 1 );
 703         close( sync_pipe[1] );
 704         break;
 705
 706     case -1:
 707         fatal_perror( "fork" );
 708         break;
 709
 710     default:  /* parent */
 711         close( sync_pipe[1] );
 712
 713         /* wait for child to signal us and then exit */
 714         if (read( sync_pipe[0], &dummy, 1 ) == 1) _exit(0);
 715
 716         /* child terminated, propagate exit status */
 717         wait4( pid, &status, 0, NULL );
 718         if (WIFEXITED(status)) _exit( WEXITSTATUS(status) );
 719         _exit(1);
 720     }
 721
 722     /* setup msghdr structure constant fields */
 723     msghdr.msg_name    = NULL;
 724     msghdr.msg_namelen = 0;
 725     msghdr.msg_iov     = &myiovec;
 726     msghdr.msg_iovlen  = 1;
 727
 728     /* init startup ticks */
 729     server_start_ticks = get_tick_count();
 730 }
 731
 732 /* master socket timer expiration handler */
 733 static void close_socket_timeout( void *arg )
 734 {
 735     master_socket->timeout = NULL;
 736     flush_registry();
 737
 738     /* if a new client is waiting, we keep on running */
 739     if (check_select_events( master_socket->obj.fd, POLLIN )) return;
 740
 741     if (debug_level) fprintf( stderr, "wineserver: exiting (pid=%ld)\n", (long) getpid() );
 742
 743 #ifdef DEBUG_OBJECTS
 744     /* shut down everything properly */
 745     release_object( master_socket );
 746     close_global_hooks();
 747     close_global_handles();
 748     close_registry();
 749     close_atom_table();
 750 #else
 751     exit(0);
 752 #endif
 753 }
 754
 755 /* close the master socket and stop waiting for new clients */
 756 void close_master_socket(void)
 757 {
 758     struct timeval when;
 759
 760     if (master_socket_timeout == -1) return;  /* just keep running forever */
 761
 762     if (master_socket_timeout)
 763     {
 764         gettimeofday( &when, 0 );
 765         add_timeout( &when, master_socket_timeout * 1000 );
 766         master_socket->timeout = add_timeout_user( &when, close_socket_timeout, NULL );
 767     }
 768     else close_socket_timeout( NULL );  /* close it right away */
 769 }
 770
 771 /* lock/unlock the master socket to stop accepting new clients */
 772 void lock_master_socket( int locked )
 773 {
 774     set_select_events( &master_socket->obj, locked ? 0 : POLLIN );
 775 }