connection.c

远程桌面连接工具

/* $TOG: connection.c /main/156 1997/06/05 18:43:01 sekhar $ */
/***********************************************************

Copyright (c) 1987, 1989  X Consortium

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
X CONSORTIUM BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

Except as contained in this notice, the name of the X Consortium shall not be
used in advertising or otherwise to promote the sale, use or other dealings
in this Software without prior written authorization from the X Consortium.


Copyright 1987, 1989 by Digital Equipment Corporation, Maynard, Massachusetts.

                        All Rights Reserved

Permission to use, copy, modify, and distribute this software and its 
documentation for any purpose and without fee is hereby granted, 
provided that the above copyright notice appear in all copies and that
both that copyright notice and this permission notice appear in 
supporting documentation, and that the name of Digital not be
used in advertising or publicity pertaining to distribution of the
software without specific, written prior permission.  

DIGITAL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING
ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL
DIGITAL BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR
ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
SOFTWARE.

******************************************************************/
/* $XFree86: xc/programs/Xserver/os/connection.c,v 3.25.2.2 1997/07/05 15:55:45 dawes Exp $ */
/*****************************************************************
 *  Stuff to create connections --- OS dependent
 *
 *      EstablishNewConnections, CreateWellKnownSockets, ResetWellKnownSockets,
 *      CloseDownConnection, CheckConnections, AddEnabledDevice,
 *	RemoveEnabledDevice, OnlyListToOneClient,
 *      ListenToAllClients,
 *
 *      (WaitForSomething is in its own file)
 *
 *      In this implementation, a client socket table is not kept.
 *      Instead, what would be the index into the table is just the
 *      file descriptor of the socket.  This won't work for if the
 *      socket ids aren't small nums (0 - 2^8)
 *
 *****************************************************************/

#ifdef WIN32
#include <X11/Xwinsock.h>
#endif
#include "X.h"
#include "Xproto.h"
#include <X11/Xtrans.h>
#include <errno.h>
#ifdef X_NOT_STDC_ENV
extern int errno;
#endif

#include <signal.h>
#include <stdio.h>

#ifndef WIN32
#ifndef MINIX
#ifndef Lynx
#include <sys/socket.h>
#else
#include <socket.h>
#endif
#endif

#ifdef hpux
#include <sys/utsname.h>
#include <sys/ioctl.h>
#endif

#ifdef AIXV3
#include <sys/ioctl.h>
#endif

#ifdef MINIX
#include <sys/nbio.h>

#define select(n,r,w,x,t) nbio_select(n,r,w,x,t)
#endif

#ifdef __EMX__
#define select(n,r,w,x,t) os2PseudoSelect(n,r,w,x,t)
extern __const__ int _nfiles;
#endif

#if defined(TCPCONN) || defined(STREAMSCONN)
# include <netinet/in.h>

/*================================================================
   BEGIN ORL VNC modification
   include arpa/inet.h for inet_ntoa function prototype */

#include <arpa/inet.h>

/* END ORL VNC modification
================================================================*/

# ifndef hpux
#  ifdef apollo
#   ifndef NO_TCP_H
#    include <netinet/tcp.h>
#   endif
#  else
#   ifdef CSRG_BASED
#    include <sys/param.h>
#   endif
#    ifndef __EMX__
#     include <netinet/tcp.h>
#    endif
#  endif
# endif
#endif

#ifdef AMTCPCONN
#include <server/ip/types.h>
#include <server/ip/gen/in.h>
#include <server/ip/gen/inet.h>
#endif

#if !defined(AMOEBA) && !defined(_MINIX) && !defined(__EMX__)
#ifndef Lynx
#include <sys/uio.h>
#else
#include <uio.h>
#endif
#endif
#endif /* WIN32 */
#include "misc.h"		/* for typedef of pointer */
#include <X11/Xpoll.h>
#include "osdep.h"
#include "opaque.h"
#include "dixstruct.h"
#ifdef XAPPGROUP
#include "extensions/Xagsrv.h"
#endif
#ifdef XCSECURITY
#define _SECURITY_SERVER
#include "extensions/security.h"
#endif
#ifdef LBX
#include "lbxserve.h"
#endif

#ifdef X_NOT_POSIX
#define Pid_t int
#else
#define Pid_t pid_t
#endif

#ifdef DNETCONN
#include <netdnet/dn.h>
#endif /* DNETCONN */

extern char *display;		/* The display number */
int lastfdesc;			/* maximum file descriptor */

fd_set WellKnownConnections;	/* Listener mask */
fd_set EnabledDevices;		/* mask for input devices that are on */
fd_set AllSockets;		/* select on this */
fd_set AllClients;		/* available clients */
fd_set LastSelectMask;		/* mask returned from last select call */
fd_set ClientsWithInput;	/* clients with FULL requests in buffer */
fd_set ClientsWriteBlocked;	/* clients who cannot receive output */
fd_set OutputPending;		/* clients with reply/event data ready to go */
int MaxClients = MAXSOCKS;
Bool NewOutputPending;		/* not yet attempted to write some new output */
Bool AnyClientsWriteBlocked;	/* true if some client blocked on write */

Bool RunFromSmartParent;	/* send SIGUSR1 to parent process */
Bool PartialNetwork;		/* continue even if unable to bind all addrs */
char *protNoListen;             /* don't listen on this protocol */
static Pid_t ParentProcess;

static Bool debug_conns = FALSE;

fd_set IgnoredClientsWithInput;
static fd_set GrabImperviousClients;
static fd_set SavedAllClients;
static fd_set SavedAllSockets;
static fd_set SavedClientsWithInput;
int GrabInProgress = 0;

#ifndef WIN32
int ConnectionTranslation[MAXSOCKS];
#else
/* SPAM ALERT !!!
 * On NT fds are not between 0 and MAXSOCKS, they are unrelated, and there is
 * not even a known maximum value, so use something quite arbitrary for now.
 * This is clearly boggus and another form of storage which doesn't use the fd
 * as a direct index should really be implemented for NT.
 */
#define MAXFD 500
int ConnectionTranslation[MAXFD];
#endif

XtransConnInfo 	*ListenTransConns = NULL;
int	       	*ListenTransFds = NULL;
int		ListenTransCount;

extern int auditTrailLevel;

static void ErrorConnMax(
#if NeedFunctionPrototypes
XtransConnInfo /* trans_conn */
#endif
);

#ifndef LBX
static
#endif
void CloseDownFileDescriptor(
#if NeedFunctionPrototypes
#ifdef LBX
    ClientPtr	client
#else
    register OsCommPtr /*oc*/
#endif
#endif
);

#ifdef LBX
extern int LbxFlushClient();
extern void LbxCloseClient();
#endif /* LBX */

static XtransConnInfo
lookup_trans_conn (fd)
    int fd;
{
    if (ListenTransFds)
    {
	int i;
	for (i = 0; i < ListenTransCount; i++)
	    if (ListenTransFds[i] == fd)
		return ListenTransConns[i];
    }

    return (NULL);
}

#ifdef XDMCP
void XdmcpOpenDisplay(), XdmcpInit(), XdmcpReset(), XdmcpCloseDisplay();
#endif

/*****************
 * CreateWellKnownSockets
 *    At initialization, create the sockets to listen on for new clients.
 *****************/

void
CreateWellKnownSockets()
{
    int		request, i;
    int		partial;
    char 	port[20];

    FD_ZERO(&AllSockets);
    FD_ZERO(&AllClients);
    FD_ZERO(&LastSelectMask);
    FD_ZERO(&ClientsWithInput);

#ifndef WIN32
    for (i=0; i<MAXSOCKS; i++) ConnectionTranslation[i] = 0;
#else
    for (i=0; i<MAXFD; i++) ConnectionTranslation[i] = 0;
#endif
#ifdef XNO_SYSCONF      /* should only be on FreeBSD 1.x and NetBSD 0.x */
#undef _SC_OPEN_MAX
#endif
#ifndef __EMX__
#ifdef _SC_OPEN_MAX
    lastfdesc = sysconf(_SC_OPEN_MAX) - 1;
#else
#ifdef hpux /* || defined(__EMX__) ? */
    lastfdesc = _NFILE - 1;
#else
    lastfdesc = getdtablesize() - 1;
#endif
#endif
#else
    lastfdesc = _nfiles - 1;
#endif

    if (lastfdesc > MAXSOCKS)
    {
	lastfdesc = MAXSOCKS;
	if (debug_conns)
	    ErrorF( "GOT TO END OF SOCKETS %d\n", MAXSOCKS);
    }

    FD_ZERO (&WellKnownConnections);

    sprintf (port, "%d", atoi (display));

    if (protNoListen)
        if (_XSERVTransNoListen(protNoListen))
        {
	    FatalError ("Failed to disable listen for %s", protNoListen);
	}
    
    if ((_XSERVTransMakeAllCOTSServerListeners (port, &partial,
	&ListenTransCount, &ListenTransConns) >= 0) &&
	(ListenTransCount >= 1))
    {
	if (!PartialNetwork && partial)
	{
	    FatalError ("Failed to establish all listening sockets");
	}
	else
	{
	    ListenTransFds = (int *) xalloc (ListenTransCount * sizeof (int));

	    for (i = 0; i < ListenTransCount; i++)
	    {
		int fd = _XSERVTransGetConnectionNumber (ListenTransConns[i]);
		
		ListenTransFds[i] = fd;
		FD_SET (fd, &WellKnownConnections);

		if (!_XSERVTransIsLocal (ListenTransConns[i]))
		{
		    DefineSelf (fd);
		}
	    }
	}
    }

    if (!XFD_ANYSET (&WellKnownConnections))
        FatalError ("Cannot establish any listening sockets - Make sure an X server isn't already running");
#ifndef WIN32
    OsSignal (SIGPIPE, SIG_IGN);
    OsSignal (SIGHUP, AutoResetServer);
#endif
    OsSignal (SIGINT, GiveUp);
    OsSignal (SIGTERM, GiveUp);
    XFD_COPYSET (&WellKnownConnections, &AllSockets);
    ResetHosts(display);
    /*
     * Magic:  If SIGUSR1 was set to SIG_IGN when
     * the server started, assume that either
     *
     *  a- The parent process is ignoring SIGUSR1
     *
     * or
     *
     *  b- The parent process is expecting a SIGUSR1
     *     when the server is ready to accept connections
     *
     * In the first case, the signal will be harmless,
     * in the second case, the signal will be quite
     * useful
     */
#ifndef WIN32
    if (OsSignal (SIGUSR1, SIG_IGN) == SIG_IGN)
	RunFromSmartParent = TRUE;
    ParentProcess = getppid ();
    if (RunFromSmartParent) {
	if (ParentProcess > 0) {
	    kill (ParentProcess, SIGUSR1);
	}
    }
#endif
#ifdef XDMCP
    XdmcpInit ();
#endif
}

void
ResetWellKnownSockets ()
{
    int i;

    ResetOsBuffers();

    for (i = 0; i < ListenTransCount; i++)
    {
	int status = _XSERVTransResetListener (ListenTransConns[i]);

	if (status != TRANS_RESET_NOOP)
	{
	    if (status == TRANS_RESET_FAILURE)
	    {
		/*
		 * ListenTransConns[i] freed by xtrans.
		 * Remove it from out list.
		 */

		FD_CLR (ListenTransFds[i], &WellKnownConnections);
		ListenTransFds[i] = ListenTransFds[ListenTransCount - 1];
		ListenTransConns[i] = ListenTransConns[ListenTransCount - 1];
		ListenTransCount -= 1;
		i -= 1;
	    }
	    else if (status == TRANS_RESET_NEW_FD)
	    {
		/*
		 * A new file descriptor was allocated (the old one was closed)
		 */

		int newfd = _XSERVTransGetConnectionNumber (ListenTransConns[i]);

		FD_CLR (ListenTransFds[i], &WellKnownConnections);
		ListenTransFds[i] = newfd;
		FD_SET(newfd, &WellKnownConnections);
	    }
	}
    }

    ResetAuthorization ();
    ResetHosts(display);