server/request.c - wine - Git at Google

 /*
  * Server-side request handling
  *
  * Copyright (C) 1998 Alexandre Julliard
  */

 #include "config.h"

 #include <assert.h>
 #include <errno.h>
 #include <fcntl.h>
 #include <pwd.h>
 #include <signal.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <stdarg.h>
 #include <string.h>
 #include <sys/stat.h>
 #include <sys/time.h>
 #include <sys/types.h>
 #ifdef HAVE_SYS_SOCKET_H
 # include <sys/socket.h>
 #endif
 #include <sys/uio.h>
 #include <sys/un.h>
 #include <unistd.h>

 #include "winnt.h"
 #include "winbase.h"
 #include "wincon.h"
 #include "thread.h"
 #include "process.h"
 #include "server.h"
 #define WANT_REQUEST_HANDLERS
 #include "request.h"
 #include "wine/port.h"

 /* Some versions of glibc don't define this */
 #ifndef SCM_RIGHTS
 #define SCM_RIGHTS 1
 #endif

  /* path names for server master Unix socket */
 #define CONFDIR    "/.wine"        /* directory for Wine config relative to $HOME */
 #define SERVERDIR  "/wineserver-"  /* server socket directory (hostname appended) */
 #define SOCKETNAME "socket"        /* name of the socket file */

 struct master_socket
 {
     struct object       obj;         /* object header */
 };

 static void master_socket_dump( struct object *obj, int verbose );
 static void master_socket_poll_event( struct object *obj, int event );
 static void master_socket_destroy( struct object *obj );

 static const struct object_ops master_socket_ops =
 {
     sizeof(struct master_socket),  /* size */
     master_socket_dump,            /* dump */
     no_add_queue,                  /* add_queue */
     NULL,                          /* remove_queue */
     NULL,                          /* signaled */
     NULL,                          /* satisfied */
     NULL,                          /* get_poll_events */
     master_socket_poll_event,      /* poll_event */
     no_get_fd,                     /* get_fd */
     no_flush,                      /* flush */
     no_get_file_info,              /* get_file_info */
     master_socket_destroy          /* destroy */
 };


 struct thread *current = NULL;  /* thread handling the current request */
 unsigned int global_error = 0;  /* global error code for when no thread is current */

 static struct master_socket *master_socket;  /* the master socket object */

 /* socket communication static structures */
 static struct iovec myiovec;
 static struct msghdr msghdr;
 #ifndef HAVE_MSGHDR_ACCRIGHTS
 struct cmsg_fd
 {
     int len;   /* sizeof structure */
     int level; /* SOL_SOCKET */
     int type;  /* SCM_RIGHTS */
     int fd;    /* fd to pass */
 };
 static struct cmsg_fd cmsg = { sizeof(cmsg), SOL_SOCKET, SCM_RIGHTS, -1 };
 #endif  /* HAVE_MSGHDR_ACCRIGHTS */

 /* complain about a protocol error and terminate the client connection */
 void fatal_protocol_error( struct thread *thread, const char *err, ... )
 {
     va_list args;

     va_start( args, err );
     fprintf( stderr, "Protocol error:%p: ", thread );
     vfprintf( stderr, err, args );
     va_end( args );
     thread->exit_code = 1;
     kill_thread( thread, 1 );
 }

 /* complain about a protocol error and terminate the client connection */
 void fatal_protocol_perror( struct thread *thread, const char *err, ... )
 {
     va_list args;

     va_start( args, err );
     fprintf( stderr, "Protocol error:%p: ", thread );
     vfprintf( stderr, err, args );
     perror( " " );
     va_end( args );
     thread->exit_code = 1;
     kill_thread( thread, 1 );
 }

 /* die on a fatal error */
 void fatal_error( const char *err, ... )
 {
     va_list args;

     va_start( args, err );
     fprintf( stderr, "wineserver: " );
     vfprintf( stderr, err, args );
     va_end( args );
     exit(1);
 }

 /* die on a fatal error */
 void fatal_perror( const char *err, ... )
 {
     va_list args;

     va_start( args, err );
     fprintf( stderr, "wineserver: " );
     vfprintf( stderr, err, args );
     perror( " " );
     va_end( args );
     exit(1);
 }

 /* call a request handler */
 static inline void call_req_handler( struct thread *thread, union generic_request *request )
 {
     enum request req = request->header.req;

     current = thread;
     clear_error();

     if (debug_level) trace_request( thread, request );

     if (request->header.var_size)
     {
         if ((unsigned int)request->header.var_offset +
                           request->header.var_size > MAX_REQUEST_LENGTH)
         {
             fatal_protocol_error( current, "bad request offset/size %d/%d\n",
                                   request->header.var_offset, request->header.var_size );
             return;
         }
     }

     if (req < REQ_NB_REQUESTS)
     {
         req_handlers[req]( request );
         if (current) send_reply( current, request );
         current = NULL;
         return;
     }
     fatal_protocol_error( current, "bad request %d\n", req );
 }

 /* read a request from a thread */
 void read_request( struct thread *thread )
 {
     union generic_request req;
     int ret;

     if ((ret = read( thread->obj.fd, &req, sizeof(req) )) == sizeof(req))
     {
         call_req_handler( thread, &req );
         return;
     }
     if (!ret)  /* closed pipe */
         kill_thread( thread, 0 );
     else if (ret > 0)
         fatal_protocol_error( thread, "partial read %d\n", ret );
     else
         fatal_protocol_perror( thread, "read" );
 }

 /* send a reply to a thread */
 void send_reply( struct thread *thread, union generic_request *request )
 {
     int ret;

     if (debug_level) trace_reply( thread, request );

     request->header.error = thread->error;

     if ((ret = write( thread->reply_fd, request, sizeof(*request) )) != sizeof(*request))
     {
         if (ret >= 0)
             fatal_protocol_error( thread, "partial write %d\n", ret );
         else if (errno == EPIPE)
             kill_thread( thread, 0 );  /* normal death */
         else
             fatal_protocol_perror( thread, "reply write" );
     }
 }

 /* receive a file descriptor on the process socket */
 int receive_fd( struct process *process )
 {
     struct send_fd data;
     int fd, ret;

 #ifdef HAVE_MSGHDR_ACCRIGHTS
     msghdr.msg_accrightslen = sizeof(int);
     msghdr.msg_accrights = (void *)&fd;
 #else  /* HAVE_MSGHDR_ACCRIGHTS */
     msghdr.msg_control    = &cmsg;
     msghdr.msg_controllen = sizeof(cmsg);
     cmsg.fd = -1;
 #endif  /* HAVE_MSGHDR_ACCRIGHTS */

     myiovec.iov_base = &data;
     myiovec.iov_len  = sizeof(data);

     ret = recvmsg( process->obj.fd, &msghdr, 0 );
 #ifndef HAVE_MSGHDR_ACCRIGHTS
     fd = cmsg.fd;
 #endif

     if (ret == sizeof(data))
     {
         struct thread *thread;

         if (data.tid) thread = get_thread_from_id( data.tid );
         else thread = (struct thread *)grab_object( process->thread_list );

         if (!thread || thread->process != process)
         {
             if (debug_level)
                 fprintf( stderr, "%08x: *fd* %d <- %d bad thread id\n",
                          (unsigned int)data.tid, data.fd, fd );
             close( fd );
         }
         else
         {
             if (debug_level)
                 fprintf( stderr, "%08x: *fd* %d <- %d\n",
                          (unsigned int)thread, data.fd, fd );
             thread_add_inflight_fd( thread, data.fd, fd );
         }
         if (thread) release_object( thread );
         return 0;
     }

     if (ret >= 0)
     {
         fprintf( stderr, "Protocol error: process %p: partial recvmsg %d for fd\n", process, ret );
         kill_process( process, NULL, 1 );
     }
     else
     {
         if (errno != EWOULDBLOCK && errno != EAGAIN)
         {
             fprintf( stderr, "Protocol error: process %p: ", process );
             perror( "recvmsg" );
             kill_process( process, NULL, 1 );
         }
     }
     return -1;
 }

 /* send an fd to a client */
 int send_client_fd( struct process *process, int fd, handle_t handle )
 {
     int ret;

     if (debug_level)
         fprintf( stderr, "%08x: *fd* %d -> %d\n", (unsigned int)current, handle, fd );

 #ifdef HAVE_MSGHDR_ACCRIGHTS
     msghdr.msg_accrightslen = sizeof(fd);
     msghdr.msg_accrights = (void *)&fd;
 #else  /* HAVE_MSGHDR_ACCRIGHTS */
     msghdr.msg_control    = &cmsg;
     msghdr.msg_controllen = sizeof(cmsg);
     cmsg.fd = fd;
 #endif  /* HAVE_MSGHDR_ACCRIGHTS */

     myiovec.iov_base = (void *)&handle;
     myiovec.iov_len  = sizeof(handle);

     ret = sendmsg( process->obj.fd, &msghdr, 0 );

     if (ret == sizeof(handle)) return 0;

     if (ret >= 0)
     {
         fprintf( stderr, "Protocol error: process %p: partial sendmsg %d\n", process, ret );
         kill_process( process, NULL, 1 );
     }
     else
     {
         fprintf( stderr, "Protocol error: process %p: ", process );
         perror( "sendmsg" );
         kill_process( process, NULL, 1 );
     }
     return -1;
 }

 static void master_socket_dump( struct object *obj, int verbose )
 {
     struct master_socket *sock = (struct master_socket *)obj;
     assert( obj->ops == &master_socket_ops );
     fprintf( stderr, "Master socket fd=%d\n", sock->obj.fd );
 }

 /* handle a socket event */
 static void master_socket_poll_event( struct object *obj, int event )
 {
     struct master_socket *sock = (struct master_socket *)obj;
     assert( obj->ops == &master_socket_ops );

     assert( sock == master_socket );  /* there is only one master socket */

     if (event & (POLLERR | POLLHUP))
     {
         /* this is not supposed to happen */
         fprintf( stderr, "wineserver: Error on master socket\n" );
         release_object( obj );
     }
     else if (event & POLLIN)
     {
         struct sockaddr_un dummy;
         int len = sizeof(dummy);
         int client = accept( master_socket->obj.fd, (struct sockaddr *) &dummy, &len );
         if (client != -1) create_process( client );
     }
 }

 /* remove the socket upon exit */
 static void socket_cleanup(void)
 {
     static int do_it_once;
     if (!do_it_once++) unlink( SOCKETNAME );
 }

 static void master_socket_destroy( struct object *obj )
 {
     socket_cleanup();
 }

 /* return the configuration directory ($WINEPREFIX or $HOME/.wine) */
 const char *get_config_dir(void)
 {
     static char *confdir;
     if (!confdir)
     {
         const char *prefix = getenv( "WINEPREFIX" );
         if (prefix)
         {
             int len = strlen(prefix);
             if (!(confdir = strdup( prefix ))) fatal_error( "out of memory\n" );
             if (len > 1 && confdir[len-1] == '/') confdir[len-1] = 0;
         }
         else
         {
             const char *home = getenv( "HOME" );
             if (!home)
             {
                 struct passwd *pwd = getpwuid( getuid() );
                 if (!pwd) fatal_error( "could not find your home directory\n" );
                 home = pwd->pw_dir;
             }
             if (!(confdir = malloc( strlen(home) + strlen(CONFDIR) + 1 )))
                 fatal_error( "out of memory\n" );
             strcpy( confdir, home );
             strcat( confdir, CONFDIR );
         }
         mkdir( confdir, 0755 );  /* just in case */
     }
     return confdir;
 }

 /* create the server directory and chdir to it */
 static void create_server_dir(void)
 {
     char hostname[64];
     char *serverdir;
     const char *confdir = get_config_dir();
     struct stat st;

     if (gethostname( hostname, sizeof(hostname) ) == -1) fatal_perror( "gethostname" );

     if (!(serverdir = malloc( strlen(confdir) + strlen(SERVERDIR) + strlen(hostname) + 1 )))
         fatal_error( "out of memory\n" );

     strcpy( serverdir, confdir );
     strcat( serverdir, SERVERDIR );
     strcat( serverdir, hostname );

     if (chdir( serverdir ) == -1)
     {
         if (errno != ENOENT) fatal_perror( "chdir %s", serverdir );
         if (mkdir( serverdir, 0700 ) == -1) fatal_perror( "mkdir %s", serverdir );
         if (chdir( serverdir ) == -1) fatal_perror( "chdir %s", serverdir );
     }
     if (stat( ".", &st ) == -1) fatal_perror( "stat %s", serverdir );
     if (!S_ISDIR(st.st_mode)) fatal_error( "%s is not a directory\n", serverdir );
     if (st.st_uid != getuid()) fatal_error( "%s is not owned by you\n", serverdir );
     if (st.st_mode & 077) fatal_error( "%s must not be accessible by other users\n", serverdir );
 }

 /* open the master server socket and start waiting for new clients */
 void open_master_socket(void)
 {
     struct sockaddr_un addr;
     int fd, slen;

     /* make sure no request is larger than the maximum size */
     assert( sizeof(union generic_request) == sizeof(struct request_max_size) );

     create_server_dir();
     if ((fd = socket( AF_UNIX, SOCK_STREAM, 0 )) == -1) fatal_perror( "socket" );
     addr.sun_family = AF_UNIX;
     strcpy( addr.sun_path, SOCKETNAME );
     slen = sizeof(addr) - sizeof(addr.sun_path) + strlen(addr.sun_path) + 1;
 #ifdef HAVE_SOCKADDR_SUN_LEN
     addr.sun_len = slen;
 #endif
     if (bind( fd, (struct sockaddr *)&addr, slen ) == -1)
     {
         if ((errno == EEXIST) || (errno == EADDRINUSE))
             exit(0);  /* pretend we succeeded to start */
         else
             fatal_perror( "bind" );
     }
     atexit( socket_cleanup );

     chmod( SOCKETNAME, 0600 );  /* make sure no other user can connect */
     if (listen( fd, 5 ) == -1) fatal_perror( "listen" );

     if (!(master_socket = alloc_object( &master_socket_ops, fd )))
         fatal_error( "out of memory\n" );
     set_select_events( &master_socket->obj, POLLIN );

     /* setup msghdr structure constant fields */
     msghdr.msg_name    = NULL;
     msghdr.msg_namelen = 0;
     msghdr.msg_iov     = &myiovec;
     msghdr.msg_iovlen  = 1;

     /* go in the background */
     switch(fork())
     {
     case -1:
         fatal_perror( "fork" );
     case 0:
         setsid();
         break;
     default:
         _exit(0);  /* do not call atexit functions */
     }
 }

 /* close the master socket and stop waiting for new clients */
 void close_master_socket(void)
 {
     /* if a new client is waiting, we keep on running */
     if (!check_select_events( master_socket->obj.fd, POLLIN ))
         release_object( master_socket );
 }

 /* lock/unlock the master socket to stop accepting new clients */
 void lock_master_socket( int locked )
 {
     set_select_events( &master_socket->obj, locked ? 0 : POLLIN );
 }
	/*
	* Server-side request handling
	*
	* Copyright (C) 1998 Alexandre Julliard
	*/

	#include "config.h"

	#include <assert.h>
	#include <errno.h>
	#include <fcntl.h>
	#include <pwd.h>
	#include <signal.h>
	#include <stdio.h>
	#include <stdlib.h>
	#include <stdarg.h>
	#include <string.h>
	#include <sys/stat.h>
	#include <sys/time.h>
	#include <sys/types.h>
	#ifdef HAVE_SYS_SOCKET_H
	# include <sys/socket.h>
	#endif
	#include <sys/uio.h>
	#include <sys/un.h>
	#include <unistd.h>

	#include "winnt.h"
	#include "winbase.h"
	#include "wincon.h"
	#include "thread.h"
	#include "process.h"
	#include "server.h"
	#define WANT_REQUEST_HANDLERS
	#include "request.h"
	#include "wine/port.h"

	/* Some versions of glibc don't define this */
	#ifndef SCM_RIGHTS
	#define SCM_RIGHTS 1
	#endif

	/* path names for server master Unix socket */
	#define CONFDIR "/.wine" /* directory for Wine config relative to $HOME */
	#define SERVERDIR "/wineserver-" /* server socket directory (hostname appended) */
	#define SOCKETNAME "socket" /* name of the socket file */

	struct master_socket
	{
	struct object obj; /* object header */
	};

	static void master_socket_dump( struct object *obj, int verbose );
	static void master_socket_poll_event( struct object *obj, int event );
	static void master_socket_destroy( struct object *obj );

	static const struct object_ops master_socket_ops =
	{
	sizeof(struct master_socket), /* size */
	master_socket_dump, /* dump */
	no_add_queue, /* add_queue */
	NULL, /* remove_queue */
	NULL, /* signaled */
	NULL, /* satisfied */
	NULL, /* get_poll_events */
	master_socket_poll_event, /* poll_event */
	no_get_fd, /* get_fd */
	no_flush, /* flush */
	no_get_file_info, /* get_file_info */
	master_socket_destroy /* destroy */
	};


	struct thread current = NULL; / thread handling the current request */
	unsigned int global_error = 0; /* global error code for when no thread is current */

	static struct master_socket master_socket; / the master socket object */

	/* socket communication static structures */
	static struct iovec myiovec;
	static struct msghdr msghdr;
	#ifndef HAVE_MSGHDR_ACCRIGHTS
	struct cmsg_fd
	{
	int len; /* sizeof structure */
	int level; /* SOL_SOCKET */
	int type; /* SCM_RIGHTS */
	int fd; /* fd to pass */
	};
	static struct cmsg_fd cmsg = { sizeof(cmsg), SOL_SOCKET, SCM_RIGHTS, -1 };
	#endif /* HAVE_MSGHDR_ACCRIGHTS */

	/* complain about a protocol error and terminate the client connection */
	void fatal_protocol_error( struct thread thread, const char err, ... )
	{
	va_list args;

	va_start( args, err );
	fprintf( stderr, "Protocol error:%p: ", thread );
	vfprintf( stderr, err, args );
	va_end( args );
	thread->exit_code = 1;
	kill_thread( thread, 1 );
	}

	/* complain about a protocol error and terminate the client connection */
	void fatal_protocol_perror( struct thread thread, const char err, ... )
	{
	va_list args;

	va_start( args, err );
	fprintf( stderr, "Protocol error:%p: ", thread );
	vfprintf( stderr, err, args );
	perror( " " );
	va_end( args );
	thread->exit_code = 1;
	kill_thread( thread, 1 );
	}

	/* die on a fatal error */
	void fatal_error( const char *err, ... )
	{
	va_list args;

	va_start( args, err );
	fprintf( stderr, "wineserver: " );
	vfprintf( stderr, err, args );
	va_end( args );
	exit(1);
	}

	/* die on a fatal error */
	void fatal_perror( const char *err, ... )
	{
	va_list args;

	va_start( args, err );
	fprintf( stderr, "wineserver: " );
	vfprintf( stderr, err, args );
	perror( " " );
	va_end( args );
	exit(1);
	}

	/* call a request handler */
	static inline void call_req_handler( struct thread thread, union generic_request request )
	{
	enum request req = request->header.req;

	current = thread;
	clear_error();

	if (debug_level) trace_request( thread, request );

	if (request->header.var_size)
	{
	if ((unsigned int)request->header.var_offset +
	request->header.var_size > MAX_REQUEST_LENGTH)
	{
	fatal_protocol_error( current, "bad request offset/size %d/%d\n",
	request->header.var_offset, request->header.var_size );
	return;
	}
	}

	if (req < REQ_NB_REQUESTS)
	{
	req_handlers[req]( request );
	if (current) send_reply( current, request );
	current = NULL;
	return;
	}
	fatal_protocol_error( current, "bad request %d\n", req );
	}

	/* read a request from a thread */
	void read_request( struct thread *thread )
	{
	union generic_request req;
	int ret;

	if ((ret = read( thread->obj.fd, &req, sizeof(req) )) == sizeof(req))
	{
	call_req_handler( thread, &req );
	return;
	}
	if (!ret) /* closed pipe */
	kill_thread( thread, 0 );
	else if (ret > 0)
	fatal_protocol_error( thread, "partial read %d\n", ret );
	else
	fatal_protocol_perror( thread, "read" );
	}

	/* send a reply to a thread */
	void send_reply( struct thread thread, union generic_request request )
	{
	int ret;

	if (debug_level) trace_reply( thread, request );

	request->header.error = thread->error;

	if ((ret = write( thread->reply_fd, request, sizeof(request) )) != sizeof(request))
	{
	if (ret >= 0)
	fatal_protocol_error( thread, "partial write %d\n", ret );
	else if (errno == EPIPE)
	kill_thread( thread, 0 ); /* normal death */
	else
	fatal_protocol_perror( thread, "reply write" );
	}
	}

	/* receive a file descriptor on the process socket */
	int receive_fd( struct process *process )
	{
	struct send_fd data;
	int fd, ret;

	#ifdef HAVE_MSGHDR_ACCRIGHTS
	msghdr.msg_accrightslen = sizeof(int);
	msghdr.msg_accrights = (void *)&fd;
	#else /* HAVE_MSGHDR_ACCRIGHTS */
	msghdr.msg_control = &cmsg;
	msghdr.msg_controllen = sizeof(cmsg);
	cmsg.fd = -1;
	#endif /* HAVE_MSGHDR_ACCRIGHTS */

	myiovec.iov_base = &data;
	myiovec.iov_len = sizeof(data);

	ret = recvmsg( process->obj.fd, &msghdr, 0 );
	#ifndef HAVE_MSGHDR_ACCRIGHTS
	fd = cmsg.fd;
	#endif

	if (ret == sizeof(data))
	{
	struct thread *thread;

	if (data.tid) thread = get_thread_from_id( data.tid );
	else thread = (struct thread *)grab_object( process->thread_list );

	if (!thread \|\| thread->process != process)
	{
	if (debug_level)
	fprintf( stderr, "%08x: fd %d <- %d bad thread id\n",
	(unsigned int)data.tid, data.fd, fd );
	close( fd );
	}
	else
	{
	if (debug_level)
	fprintf( stderr, "%08x: fd %d <- %d\n",
	(unsigned int)thread, data.fd, fd );
	thread_add_inflight_fd( thread, data.fd, fd );
	}
	if (thread) release_object( thread );
	return 0;
	}

	if (ret >= 0)
	{
	fprintf( stderr, "Protocol error: process %p: partial recvmsg %d for fd\n", process, ret );
	kill_process( process, NULL, 1 );
	}
	else
	{
	if (errno != EWOULDBLOCK && errno != EAGAIN)
	{
	fprintf( stderr, "Protocol error: process %p: ", process );
	perror( "recvmsg" );
	kill_process( process, NULL, 1 );
	}
	}
	return -1;
	}

	/* send an fd to a client */
	int send_client_fd( struct process *process, int fd, handle_t handle )
	{
	int ret;

	if (debug_level)
	fprintf( stderr, "%08x: fd %d -> %d\n", (unsigned int)current, handle, fd );

	#ifdef HAVE_MSGHDR_ACCRIGHTS
	msghdr.msg_accrightslen = sizeof(fd);
	msghdr.msg_accrights = (void *)&fd;
	#else /* HAVE_MSGHDR_ACCRIGHTS */
	msghdr.msg_control = &cmsg;
	msghdr.msg_controllen = sizeof(cmsg);
	cmsg.fd = fd;
	#endif /* HAVE_MSGHDR_ACCRIGHTS */

	myiovec.iov_base = (void *)&handle;
	myiovec.iov_len = sizeof(handle);

	ret = sendmsg( process->obj.fd, &msghdr, 0 );

	if (ret == sizeof(handle)) return 0;

	if (ret >= 0)
	{
	fprintf( stderr, "Protocol error: process %p: partial sendmsg %d\n", process, ret );
	kill_process( process, NULL, 1 );
	}
	else
	{
	fprintf( stderr, "Protocol error: process %p: ", process );
	perror( "sendmsg" );
	kill_process( process, NULL, 1 );
	}
	return -1;
	}

	static void master_socket_dump( struct object *obj, int verbose )
	{
	struct master_socket sock = (struct master_socket )obj;
	assert( obj->ops == &master_socket_ops );
	fprintf( stderr, "Master socket fd=%d\n", sock->obj.fd );
	}

	/* handle a socket event */
	static void master_socket_poll_event( struct object *obj, int event )
	{
	struct master_socket sock = (struct master_socket )obj;
	assert( obj->ops == &master_socket_ops );

	assert( sock == master_socket ); /* there is only one master socket */

	if (event & (POLLERR \| POLLHUP))
	{
	/* this is not supposed to happen */
	fprintf( stderr, "wineserver: Error on master socket\n" );
	release_object( obj );
	}
	else if (event & POLLIN)
	{
	struct sockaddr_un dummy;
	int len = sizeof(dummy);
	int client = accept( master_socket->obj.fd, (struct sockaddr *) &dummy, &len );
	if (client != -1) create_process( client );
	}
	}

	/* remove the socket upon exit */
	static void socket_cleanup(void)
	{
	static int do_it_once;
	if (!do_it_once++) unlink( SOCKETNAME );
	}

	static void master_socket_destroy( struct object *obj )
	{
	socket_cleanup();
	}

	/* return the configuration directory ($WINEPREFIX or $HOME/.wine) */
	const char *get_config_dir(void)
	{
	static char *confdir;
	if (!confdir)
	{
	const char *prefix = getenv( "WINEPREFIX" );
	if (prefix)
	{
	int len = strlen(prefix);
	if (!(confdir = strdup( prefix ))) fatal_error( "out of memory\n" );
	if (len > 1 && confdir[len-1] == '/') confdir[len-1] = 0;
	}
	else
	{
	const char *home = getenv( "HOME" );
	if (!home)
	{
	struct passwd *pwd = getpwuid( getuid() );
	if (!pwd) fatal_error( "could not find your home directory\n" );
	home = pwd->pw_dir;
	}
	if (!(confdir = malloc( strlen(home) + strlen(CONFDIR) + 1 )))
	fatal_error( "out of memory\n" );
	strcpy( confdir, home );
	strcat( confdir, CONFDIR );
	}
	mkdir( confdir, 0755 ); /* just in case */
	}
	return confdir;
	}

	/* create the server directory and chdir to it */
	static void create_server_dir(void)
	{
	char hostname[64];
	char *serverdir;
	const char *confdir = get_config_dir();
	struct stat st;

	if (gethostname( hostname, sizeof(hostname) ) == -1) fatal_perror( "gethostname" );

	if (!(serverdir = malloc( strlen(confdir) + strlen(SERVERDIR) + strlen(hostname) + 1 )))
	fatal_error( "out of memory\n" );

	strcpy( serverdir, confdir );
	strcat( serverdir, SERVERDIR );
	strcat( serverdir, hostname );

	if (chdir( serverdir ) == -1)
	{
	if (errno != ENOENT) fatal_perror( "chdir %s", serverdir );
	if (mkdir( serverdir, 0700 ) == -1) fatal_perror( "mkdir %s", serverdir );
	if (chdir( serverdir ) == -1) fatal_perror( "chdir %s", serverdir );
	}
	if (stat( ".", &st ) == -1) fatal_perror( "stat %s", serverdir );
	if (!S_ISDIR(st.st_mode)) fatal_error( "%s is not a directory\n", serverdir );
	if (st.st_uid != getuid()) fatal_error( "%s is not owned by you\n", serverdir );
	if (st.st_mode & 077) fatal_error( "%s must not be accessible by other users\n", serverdir );
	}

	/* open the master server socket and start waiting for new clients */
	void open_master_socket(void)
	{
	struct sockaddr_un addr;
	int fd, slen;

	/* make sure no request is larger than the maximum size */
	assert( sizeof(union generic_request) == sizeof(struct request_max_size) );

	create_server_dir();
	if ((fd = socket( AF_UNIX, SOCK_STREAM, 0 )) == -1) fatal_perror( "socket" );
	addr.sun_family = AF_UNIX;
	strcpy( addr.sun_path, SOCKETNAME );
	slen = sizeof(addr) - sizeof(addr.sun_path) + strlen(addr.sun_path) + 1;
	#ifdef HAVE_SOCKADDR_SUN_LEN
	addr.sun_len = slen;
	#endif
	if (bind( fd, (struct sockaddr *)&addr, slen ) == -1)
	{
	if ((errno == EEXIST) \|\| (errno == EADDRINUSE))
	exit(0); /* pretend we succeeded to start */
	else
	fatal_perror( "bind" );
	}
	atexit( socket_cleanup );

	chmod( SOCKETNAME, 0600 ); /* make sure no other user can connect */
	if (listen( fd, 5 ) == -1) fatal_perror( "listen" );

	if (!(master_socket = alloc_object( &master_socket_ops, fd )))
	fatal_error( "out of memory\n" );
	set_select_events( &master_socket->obj, POLLIN );

	/* setup msghdr structure constant fields */
	msghdr.msg_name = NULL;
	msghdr.msg_namelen = 0;
	msghdr.msg_iov = &myiovec;
	msghdr.msg_iovlen = 1;

	/* go in the background */
	switch(fork())
	{
	case -1:
	fatal_perror( "fork" );
	case 0:
	setsid();
	break;
	default:
	_exit(0); /* do not call atexit functions */
	}
	}

	/* close the master socket and stop waiting for new clients */
	void close_master_socket(void)
	{
	/* if a new client is waiting, we keep on running */
	if (!check_select_events( master_socket->obj.fd, POLLIN ))
	release_object( master_socket );
	}

	/* lock/unlock the master socket to stop accepting new clients */
	void lock_master_socket( int locked )
	{
	set_select_events( &master_socket->obj, locked ? 0 : POLLIN );
	}