Xdummy

#!/bin/sh
#
# Xdummy: an LD_PRELOAD hack to run a stock XFree86(1) or Xorg(1) server
# with the "dummy" video driver to make it avoid Linux VT switching, etc.
#
# Run "Xdummy -help" for more info.
#
xserver=""
geom=""
install=""
uninstall=""
root=1
debug=""
strace=""
runit=1
prconf=""
noconf=""

PATH=$PATH:/bin:/usr/bin
export PATH

program=`basename "$0"`

help () {
	${PAGER:-more} << END

$program: a hack to run a stock XFree86(1) or Xorg(1) server with the
"dummy" video driver such that it AVOIDS the Linux VT switching, keyboard
mouse conflicts, etc associated with normal use of "dummy".  

In other words, try to make XFree86/Xorg with the Device "dummy" driver
act more like Xvfb(1).

To achieve this, while running the real Xserver $program intercepts system
and library calls via the LD_PRELOAD method and modifies the behavior
to make it work correctly (i.e. avoid the VT stuff).  LD_PRELOAD tricks
are usually "clever hacks" and so might not work in all circumstances.

The primary motivation for the Xdummy script is to provide a virtual X
server for x11vnc but with more features than Xvfb (or Xvnc), however
it could be used for other reasons (e.g. better automated testing than
with Xvfb).

Currently this program needs to be run as root, since it is too difficult
to trick it otherwise.  Hopefully this will be relaxed at a later date
if the needed tricks are discovered.

Also, gcc/cc is required to compile the LD_PRELOAD shared object.
See -install and -uninstall described below.


Usage:

	$program <${program}-args> [--] <Xserver-args>


Examples:

	$program :1

	$program -debug -tmpdir ~/mytmp :1

	$program -install

startx example:

	startx -e bash -- $program :2 -depth 16

	(startx needs to be run as root, you can su(1) to a normal user
	in the bash shell and then launch ~/.xinitrc or ~/.xsession,
	gnome-session, startkde, startxfce4, etc.)

xdm example:

	xdm -config /usr/local/dummy/xdm-config -nodaemon

	where the xdm-config file has line:

	     DisplayManager.servers:         /usr/local/dummy/Xservers

	and /usr/local/dummy/Xservers has lines:

	     :1 local /usr/local/dummy/Xdummy :1 -debug
	     :2 local /usr/local/dummy/Xdummy :2 -debug

gdm/kdm example:

	TBD.

Root permission and x11vnc:

	This program needs to be run as root.  One could run x11vnc as
	root with -unixpw (it switches to the user that logs in) and
	that may be OK, some other ideas:

	- add this to sudo via visudo:

		ALL ALL = NOPASSWD: /usr/local/bin/Xdummy

	- use this little suid wrapper:
/* 
 * xdummy.c
 *
   cc -o ./xdummy xdummy.c
   sudo cp ./xdummy /usr/local/bin/xdummy
   sudo chown root:root /usr/local/bin/xdummy
   sudo chmod u+s /usr/local/bin/xdummy
 *
 */
#include <unistd.h>
#include <stdlib.h>
#include <sys/types.h>
#include <stdio.h>

int main (int argc, char *argv[]) {
	extern char **environ;
	char str[100];
	sprintf(str, "XDUMMY_UID=%d", (int) getuid());
	putenv(str);
	setuid(0);  
	setgid(0);
	execv("/usr/local/bin/Xdummy", argv); 
	exit(1);
	return 1;
}


Options:

    ${program}-args:

	-install	Compile the LD_PRELOAD shared object and install it
			next to the $program script file as: $0.so

			When that file exists it is used as the LD_PRELOAD
			shared object without recompiling.  Otherwise,
			each time $program is run the LD_PRELOAD shared
			object is compiled as a file in /tmp (or -tmpdir).

	-uninstall	Remove the file: $0.so
			The LD_PRELOAD shared object will then be compiled
			each time this program is run.

	Note: the X server is not started under -install or -uninstall.


	:N		The DISPLAY can be the first $program argument.
			It is passed to the real X server.  This is to
			aid use with startx(1), xinit(1), xdm(1), etc.

	-geom geom1[,geom2...]  Take the geometry (e.g. 1024x768) or
			list of geometries and insert them into the
			Screen section of the tweaked X server 
			config file.  Use this to have a smaller geometry
			than the one in the system config file.

	-tmpdir dir	Specify a temporary directory, owned by you and
			only writable by you.  This is used in place of
			/tmp/Xdummy.\$USER/  to placed the $program.so
			shared object, tweaked config files, etc.

	-nonroot	Try to run in non-root mode (XXX NOT yet working).

	-nosudo		Do not try to use sudo(1) when re-running as root,
			use su(1) instead.

	-xserver path	Specify the path to the Xserver to use.  Default
			is to try "Xorg" first and then "XFree86".  If
			those are not in \$PATH, use these locations:
				/usr/X11R6/bin/Xorg
				/usr/X11R6/bin/XFree86

	-n		Do not run the command to start the X server,
			just show the command that $program would run.
			The LD_PRELOAD shared object will be built,
			if needed.

	-prconf		Print, to stdout, the tweaked Xorg or XFree86
			config file (-config and -xf86config server
			options, respectively).  The Xserver is not
			started.

	-noconf		Do not tweak the Xorg or XFree86 config file
			(system or server command line) at all.  It is
			up to you to make sure it is a working config
			file (e.g. "dummy" driver, etc).  Perhaps you
			want to use a file based on -prconf output.

	-debug		Extra debugging output.

	-strace		strace(1) the Xserver process (for debugging).

	-h, -help	Print out this help.


    Xserver-args:

	Most of the XFree86 and Xorg options will work.  Important ones
	that may be supplied if missing:

	:N		X Display number for server to use.

	vtNN		Linux virtual terminal (VT) to use (a VT is currently
			still used, just not switched to and from).

	-config file		Driver "dummy" tweaked config file, a
	-xf86config file	number of settings are tweaked besides Driver.

	If -config/-xf86config is not given, the system one is used.
	Any settings in the config file that are not consistent with
	"dummy" mode will be overwritten (unless -noconf is used).

Notes:

    The XFree86/Xorg "dummy" driver is currently undocmented.  It works
    well in this mode, but it is evidently not intended for end users.

    If the display Xserver-arg (e.g. :1) is not given, or ":" or ":9999"
    is given that indicates $program should try to find a free one.

    If the display virtual terminal, VT, (e.g. vt9) is not given that
    indicates $program should try to find a free one (or guess a high one). 
    
    This program is not completely secure WRT files in /tmp (but it
    tries to some degree).  Better is to use the -tmpdir option to supply a
    directory only writable by you.  Even better is to get rid of users on
    the local machine you do not trust :-)

END
}

warn() {
	echo "$*" 1>&2
}
#set -xv

if [ "X$XDUMMY_UID" = "X" ]; then
	XDUMMY_UID=`id -u`
	export XDUMMY_UID
fi
if [ "X$XDUMMY_UID" = "X0" ]; then
	if [ "X$SUDO_UID" != "X" ]; then
		XDUMMY_UID=$SUDO_UID
		export XDUMMY_UID
	fi
fi

#warn "id: `id -u`"
# See if it needs to be run as root:
if [ "X$XDUMMY_SU_EXEC" = "X" -a "X`id -u`" != "X0"  ]; then
	dosu=1
	nosudo=""
	XDUMMY_SU_EXEC=1
	export XDUMMY_SU_EXEC
	for arg in $*
	do
		#echo "arg=$arg"
		if [ "X$arg" = "X-nonroot" ]; then
			dosu=""
		elif [ "X$arg" = "X-noroot" ]; then
			dosu=""
		elif [ "X$arg" = "X-nosudo" ]; then
			nosudo="1"
		elif [ "X$arg" = "X-help" ]; then
			dosu=""
		elif [ "X$arg" = "X-h" ]; then
			dosu=""
		elif [ "X$arg" = "X-install" ]; then
			dosu=""
		elif [ "X$arg" = "X-uninstall" ]; then
			dosu=""
		elif [ "X$arg" = "X-n" ]; then
			dosu=""
		elif [ "X$arg" = "X-prconf" ]; then
			dosu=""
		elif [ "X$arg" = "X--" ]; then
			break
		fi
	done
	if [ $dosu ]; then
		warn "$program: currently needs to be run as root to work."
		if type sudo > /dev/null 2>&1; then
			:
		else
			nosudo=1
		fi
		if [ "X$nosudo" = "X" ]; then
			warn "$program: supply the sudo password to restart as root:"
			if [ "X$XDUMMY_UID" != "X" ]; then
				exec sudo $0 -uid $XDUMMY_UID "$@"
			else
				exec sudo $0 "$@"
			fi
		else
			warn "$program: supply the root password to restart as root:"
			if [ "X$XDUMMY_UID" != "X" ]; then
				exec su -c "$0 -uid $XDUMMY_UID $*"
			else
				exec su -c "$0 $*"
			fi
		fi
		exit
	fi
fi

#warn "args: $*"
disp=""
# Process Xdummy args:
while [ "X$1" != "X" ]
do
    case $1 in 
	":"*)	disp=$1
                ;;
	"-install") install=1
                ;;
	"-uninstall") uninstall=1
                ;;
	"-nonroot") root=""
                ;;
	"-noroot") root=""
                ;;
	"-nosudo") nosudo=1
                ;;
	"-xserver") xserver="$2"; shift
                ;;
	"-uid") XDUMMY_UID="$2"; shift
		export XDUMMY_UID
                ;;
	"-geom"*) geom="$2"; shift
                ;;
	"-tmpdir") XDUMMY_TMPDIR="$2"; shift
                ;;
	"-n") runit=""
                ;;
	"-no") runit=""
                ;;
	"-prconf") prconf=1
                ;;
	"-noconf") noconf=1
                ;;
	"-debug") debug=1
                ;;
	"-nodebug") debug=""
                ;;
	"-strace") strace=1
                ;;
	"-h"*)	help; exit 0
                ;;
	"--")	shift; break
                ;;
	*)	break
                ;;
    esac
    shift
done

# Try to get a username for use in our tmp directory, etc.
user=""
if [ X`id -u` = "X0"  ]; then
	user=root	# this will also be used below for id=0
elif [ "X$USER" != "X" ]; then
	user=$USER
elif [ "X$LOGNAME" != "X" ]; then
	user=$LOGNAME
fi
# keep trying...
if [ "X$user" = "X" ]; then
	user=`whoami 2>/dev/null`
fi
if [ "X$user" = "X" ]; then
	user=`basename "$HOME"`
fi
if [ "X$user" = "X" -o "X$user" = "X." ]; then
	user="u$$"
fi

if [ "X$debug" = "X1" ]; then
	echo ""
	echo "/usr/bin/env:"
	env
	echo ""
fi

# Function to compile the LD_PRELOAD shared object:
make_so() {

	# extract code embedded in this script into a tmp C file: 
	n1=`grep -n '^#code_begin' $0 | head -1 | awk -F: '{print $1}'`
	n2=`grep -n '^#code_end'   $0 | head -1 | awk -F: '{print $1}'`
	n1=`expr $n1 + 1`
	dn=`expr $n2 - $n1`

	tmp=$tdir/Xdummy.$$.c
	rm -f $tmp
	if [ -e $tmp -o -h $tmp ]; then
		warn "$tmp still exists."
		exit 1
	fi
	#tail +$n1 $0 | head -$dn > $tmp
	tail -n +$n1 $0 | head -n $dn > $tmp

	# compile it to Xdummy.so:
	rm -f $SO
	touch $SO
	if [ ! -f $SO ]; then
		SO=$tdir/Xdummy.$user.so
		warn "warning switch LD_PRELOAD shared object to: $SO"
	fi
	rm -f $SO

	# we assume gcc:
	cc -shared -fPIC -o $SO $tmp
	rc=$?
	rm -f $tmp
	if [ $rc != 0 ]; then
		warn "$program: cannot build $SO"
		exit 1
	fi
	if [ "X$debug" != "X" -o "X$install" != "X" ]; then
		warn "$program: created $SO"
		ls -l "$SO"
	fi
}

# Set tdir to tmp dir for make_so():
if [ "X$XDUMMY_TMPDIR" != "X" ]; then
	tdir=$XDUMMY_TMPDIR
	mkdir -p $tdir
else
	tdir="/tmp"
fi

# Handle -install/-uninstall case:
SO=$0.so
if [ "X$install" != "X" -o "X$uninstall" != "X" ]; then
	if [ -e $SO -o -h $SO ]; then
		warn "removing $SO"
	fi
	rm -f $SO
	if [ -e $SO -o -h $SO ]; then
		# not good...
		warn "warning: $SO still exists."
		exit 1
	fi
	if [ $install ]; then
		make_so
		if [ ! -f $SO ]; then
			exit 1
		fi
	fi
	exit 0
fi

# We need a tmp directory for the .so, tweaked config file, and for
# redirecting filenames we cannot create (under -nonroot, not yet
# working).
#
if [ "X$XDUMMY_TMPDIR" = "X" ]; then
	XDUMMY_TMPDIR="/tmp/Xdummy.$user"
fi
tmp=$XDUMMY_TMPDIR
if echo "$tmp" | grep '^/tmp' > /dev/null; then
	if [ "X$tmp" != "X/tmp" -a "X$tmp" != "X/tmp/" ]; then
		# clean this subdir of /tmp out, otherwise leave it...
		rm -rf $XDUMMY_TMPDIR
		if [ -e $XDUMMY_TMPDIR ]; then
			warn "$XDUMMY_TMPDIR still exists"
			exit 1
		fi
	fi
fi

mkdir -p $XDUMMY_TMPDIR
chmod 700 $XDUMMY_TMPDIR

# see if we can write something there:
tfile="$XDUMMY_TMPDIR/test.file"
touch $tfile
if [ ! -f $tfile ]; then
	XDUMMY_TMPDIR="/tmp/Xdummy.$$.$USER"
	warn "warning: setting tmpdir to $XDUMMY_TMPDIR ..."
	rm -rf $XDUMMY_TMPDIR || exit 1
	mkdir -p $XDUMMY_TMPDIR || exit 1
fi
rm -f $tfile

export XDUMMY_TMPDIR

# compile the LD_PRELOAD shared object if needed:
if [ ! -f $SO ]; then
	SO="$XDUMMY_TMPDIR/Xdummy.so"
	make_so
fi

# decide which X server to use:
if [ "X$xserver" = "X" ]; then
	if type Xorg >/dev/null 2>&1; then
		xserver="Xorg"
	elif type XFree86 >/dev/null 2>&1; then
		xserver="XFree86"
	elif -x /usr/X11R6/bin/Xorg; then
		xserver="/usr/X11R6/bin/Xorg"
	elif -x /usr/bin/Xorg; then
		xserver="/usr/bin/Xorg"
	elif -x /usr/X11R6/bin/XFree86; then
		xserver="/usr/X11R6/bin/XFree86"
	fi
	if [ "X$xserver" = "X" ]; then
		# just let it fail below.
		xserver="/usr/X11R6/bin/Xorg"
		warn "$program: cannot locate a stock Xserver... assuming $xserver"
	fi
fi

# see if the binary is suid or not readable under -nonroot (XXX not yet useful):
xserver_path=`type -p $xserver 2>/dev/null`
if [ -e "$xserver_path" -a "X$root" = "X" -a "X$runit" != "X" ]; then
	if [ ! -r $xserver_path -o -u $xserver_path ]; then
		# XXX not quite correct with rm -rf $XDUMMY_TMPDIR ...
		base=`basename "$xserver_path"`
		#new="$tdir/$base.$user"
		new="/tmp/$base.$user"
		if [ ! -e $new ]; then
			warn "NEED TO COPY UNREADABLE $xserver_path to $new as root:"
			warn ""
			ls -l $xserver_path 1>&2
			warn ""
			warn "This only needs to be done once."
			warn "Please supply root passwd to 'su -c'"
			touch $new || exit 1
			chmod 700 $new || exit 1
			su -c "cat $xserver_path > $new"
			ls -l $new
			warn "Please restart."
			exit 0
		elif [ ! -O $new ]; then
			warn "file \"$new\" not owned by us!"
			ls -l $new
			exit 1
		fi
		xserver=$new
	fi 
fi

# work out display:
if [ "X$disp" != "X" ]; then
	:
elif [ "X$1" != "X" ]; then
	if echo "$1" | grep '^:[0-9]' > /dev/null; then
		disp=$1
		shift
	elif [ "X$1" = "X:" ]; then
		# ":" means for us to find one.
		shift
	fi
fi
if [ "X$disp" = "X" -o "X$disp" = "X:" ]; then
	# try to find an open display port:
	ports=`netstat -ant | grep LISTEN | awk '{print $4}' | sed -e 's/^.*://'`
	n=0
	while [ $n -le 20 ]
	do
		port=`printf "60%02d" $n`
		if echo "$ports" | grep "^${port}\$" > /dev/null; then
			:
		else
			disp=":$n"
			warn "$program: auto-selected DISPLAY $disp"
			break	
		fi
		n=`expr $n + 1`
	done
fi

# work out which vt to use, try to find an open one if necessary.
vt=""
for arg in $*
do
	if echo "$arg" | grep '^vt' > /dev/null; then
		vt=$arg
		break
	fi
done
if [ "X$vt" = "X" ]; then
	if [ "X$user" = "Xroot" ]; then
		# root can user fuser(1) to see if it is in use:
		if type fuser >/dev/null 2>&1; then
			# try /dev/tty17 thru /dev/tty32
			n=17
			while [ $n -le 32 ]
			do
				dev="/dev/tty$n"
				if fuser $dev >/dev/null 2>&1; then
					:
				else
					vt="vt$n"
					warn "$program: auto-selected VT $vt => $dev"
					break
				fi
				n=`expr $n + 1`
			done
		fi
	fi
	if [ "X$vt" = "X" ]; then
		# take a wild guess...
		vt=vt16
		warn "$program: selected VT $vt"
	fi
else
	vt=""
fi

# decide flavor of Xserver:
stype=`basename "$xserver"`
if echo "$stype" | grep -i xorg > /dev/null; then
	stype=xorg
else
	stype=xfree86
fi

# work out config file and tweak it.
next=""
config=""
got_config=""
for arg in $*
do
	if [ $next ]; then
		config="$arg"
		got_config=1
		break
	fi
	if [ "X$arg" = "X-xf86config" ]; then
		stype="xfree86"
		next=1
	elif [ "X$arg" = "X-config" ]; then
		stype="xorg"
		next=1
	fi
done

tweak_config() {
    in="$1"
    config2="$XDUMMY_TMPDIR/xconfig"
    if [ "X$disp" != "X" ]; then
    	d=`echo "$disp" | sed -e 's,/,,g' -e 's/:/_:/g'`
	config2="$config2$d"
    fi
    
    # perl script to tweak the config file... add/delete options, etc.
    XDUMMY_GEOM=$geom; export XDUMMY_GEOM
    perl > $config2 < $in -e '
    $n = 0;
    $geom = $ENV{XDUMMY_GEOM};
    if ($geom ne "") {
    	$tmp = "";
	foreach $g (split(/,/, $geom)) {
		$tmp .= "\"$g\" ";
	}
	$tmp =~ s/\s*$//;
	$geom = $tmp;
    }
    while (<>) {
	$n++;
	if (/^\s*#/) {
		# pass comments straight thru
		print;
		next;
	}
	if (/^\s*Section\s+(\S+)/i) {
		# start of Section
		$sect = $1;
		$sect =~ s/\W//g;
		$sect =~ y/A-Z/a-z/;
		$sects{$sect} = 1;
		print;
		next;
	}
	if (/^\s*EndSection/) {
		# end of Section
		if ($sect eq "serverflags") {
			if (!$got_DontVTSwitch) {
				print "  ##Xdummy:##\n";
				print "  Option \"DontVTSwitch\" \"true\"\n";
			}
			if (!$got_AllowMouseOpenFail) {
				print "  ##Xdummy:##\n";
				print "  Option \"AllowMouseOpenFail\" \"true\"\n";
			}
			if (!$got_PciForceNone) {
				print "  ##Xdummy:##\n";
				print "  Option \"PciForceNone\" \"true\"\n";
			}
		} elsif ($sect eq "device") {
			if (!$got_Driver) {
				print "  ##Xdummy:##\n";
				print "  Driver \"dummy\"\n";
			}
			if (!$got_VideoRam) {
				print "  ##Xdummy:##\n";
				print "  VideoRam 16000\n";
			}
		}
		$sect = "";
		print;
		next;
	}
	$l = $_;
	$l =~ s/#.*$//;
	if ($sect eq "serverflags") {
		if ($l =~ /^\s*Option.*DontVTSwitch/i) {
			$_ =~ s/false/true/ig;
			$got_DontVTSwitch = 1;
		}
		if ($l =~ /^\s*Option.*AllowMouseOpenFail/i) {
			$_ =~ s/false/true/ig;
			$got_AllowMouseOpenFail = 1;
		}
		if ($l =~ /^\s*Option.*PciForceNone/i) {
			$_ =~ s/false/true/ig;
			$got_PciForceNone= 1;
		}
	}
	if ($sect eq "module") {
		if ($l =~ /^\s*Load.*\b(dri|fbdevhw)\b/i) {
			$_ = "##Xdummy## $_";
		}
	}
	if ($sect eq "device") {
		if ($l =~ /^(\s*Driver)\b/i) {
			$_ = "$1 \"dummy\"\n";
			$got_Driver = 1;
		}
		if ($l =~ /^\s*VideoRam/i) {
			$got_VideoRam= 1;
		}
	}
	if ($sect eq "inputdevice") {
		if ($l =~ /^\s*Option.*\bDevice\b/i) {
			print "  ##Xdummy:##\n";
			$_ = "  Option \"Device\" \"/dev/dilbert$n\"\n";
		}
	}
	if ($sect eq "screen") {
		if ($geom ne "") {
			if ($l =~ /^(\s*Modes)\b/i) {
				$_ = "$1 $geom\n";
				print "  ##Xdummy:##\n";
				$got_Modes = 1;
			}
		}
	}
	print;
    }
    # create any crucial sections that are missing:
    if (! exists($sects{serverflags})) {
	print "\n##Xdummy:##\n";
    	print "Section \"ServerFlags\"\n";
    	print "  Option \"DontVTSwitch\" \"true\"\n";
    	print "  Option \"AllowMouseOpenFail\" \"true\"\n";
    	print "  Option \"PciForceNone\" \"true\"\n";
    	print "EndSection\n";
    }
    if (! exists($sects{device})) {
	print "\n##Xdummy:##\n";
    	print "Section \"Device\"\n";
    	print "  Identifier \"Videocard0\"\n";
    	print "  Driver \"dummy\"\n";
	print "  VideoRam 16000\n";
    	print "EndSection\n";
    }
    if (! exists($sects{monitor})) {
	print "\n##Xdummy:##\n";
    	print "Section \"Monitor\"\n";
    	print "  Identifier \"Monitor0\"\n";
    	print "  HorizSync   30.0 - 130.0\n";
    	print "  VertRefresh 50.0 - 250.0\n";
    	print "EndSection\n";
    }
    if (! exists($sects{screen})) {
	print "\n##Xdummy:##\n";
    	print "Section \"Screen\"\n";
    	print "  Identifier \"Screen0\"\n";
    	print "  Device \"Videocard0\"\n";
    	print "  Monitor \"Monitor0\"\n";
    	print "  DefaultDepth 16\n";
    	print "  SubSection \"Display\"\n";
    	print "    Viewport 0 0\n";
    	print "    Depth 16\n";
    	print "    Modes \"1024x768\" \"800x600\" \"640x480\"\n";
    	print "  EndSubSection\n";
    	print "EndSection\n";
    }
';
}

args="$*"
if [ ! $noconf ]; then
	# tweaked config will be put in $config2:
	config2=""
	if [ "X$config" != "X" ]; then
		if [ ! -f $config ]; then
			config="/etc/X11/$config"
		fi
	else
		# use the default one:
		if [ "X$stype" = "Xxorg" ]; then
			config=/etc/X11/xorg.conf
		else
			if [ -f "/etc/X11/XF86Config-4" ]; then
				config="/etc/X11/XF86Config-4"
			else
				config="/etc/X11/XF86Config"
			fi
		fi
		if [ ! -f $config ]; then
			for c in /etc/X11/xorg.conf /etc/X11/XF86Config-4 /etc/X11/XF86Config
			do
				if [ -f $c ]; then
					config=$c
					break
				fi
			done
		fi
	fi

	if [ -f $config ]; then
		tweak_config $config
	fi

	# now we need to get our tweaked config file onto the command line:
	if [ ! $got_config ]; then
		# append:
		if [ "X$stype" = "Xxorg" ]; then
			args="$args -config FUBAR"
		else
			args="$args -xf86config FUBAR"
		fi
	fi
	if [ "X$config2" != "X" ]; then
		# or modify $args:
		args=`echo "$args" | sed \
			-e "s,-config  *[^ ][^ ]*,-config $config2,g" \
			-e "s,-xf86config  *[^ ][^ ]*,-xf86config $config2,g"`
	fi
fi

if [ $prconf ]; then
	warn ""
	warn "The Xorg/XFree86 server config file is:"
	warn ""
	if [ "X$config2" = "X" ]; then
		warn "NO CONFIG GENERATED."
	else
		cat "$config2"
	fi
	exit
fi

if [ $debug ]; then
	XDUMMY_DEBUG=1
	export XDUMMY_DEBUG
fi
if [ $root ]; then
	XDUMMY_ROOT=1
	export XDUMMY_ROOT
fi

# finally, run it:
if [ "X$debug" != "X" -o "X$runit" = "X" ]; then
	warn ""
	warn "The command to run is:"
	warn ""
	so=$SO
	pwd=`pwd`
	if echo "$so" | grep '^\./' > /dev/null; then
		so=`echo "$so" | sed -e "s,^\.,$pwd,"`
	fi
	if echo "$so" | grep '/' > /dev/null; then
		:
	else
		so="$pwd/$so"
	fi
	warn "env LD_PRELOAD=$so $xserver $disp $args $vt"
	warn ""
	if [ ! $runit ]; then
		exit 0
	fi
fi
if [ $strace ]; then
	strace -f env LD_PRELOAD=$SO $xserver $disp $args $vt
else
	exec env LD_PRELOAD=$SO $xserver $disp $args $vt
fi

exit $?
#########################################################################

code() {
#code_begin
#include <stdio.h>
#define O_ACCMODE          0003
#define O_RDONLY             00
#define O_WRONLY             01
#define O_RDWR               02
#define O_CREAT            0100 /* not fcntl */
#define O_EXCL             0200 /* not fcntl */
#define O_NOCTTY           0400 /* not fcntl */
#define O_TRUNC           01000 /* not fcntl */
#define O_APPEND          02000
#define O_NONBLOCK        04000
#define O_NDELAY        O_NONBLOCK
#define O_SYNC           010000
#define O_FSYNC          O_SYNC
#define O_ASYNC          020000

#include <unistd.h>
#include <stdlib.h>
#include <string.h>

#include <linux/vt.h>
#include <linux/kd.h>

#define __USE_GNU
#include <dlfcn.h>

static char tmpdir[1024];
static char str1[1024];
static char str2[1024];

static char devs[256][1024];
static int debug = -1;
static int root = -1;
static int changed_uid = 0;
static int saw_fonts = 0;

#if 0
typedef long time_t;
#endif
static time_t start = 0; 

void check_debug(void) {
	if (debug < 0) {
		if (getenv("XDUMMY_DEBUG") != NULL) {
			debug = 1;
		} else {
			debug = 0;
		}
		putenv("LD_PRELOAD=");
	}
}
void check_root(void) {
	if (root < 0) {
		if (getenv("XDUMMY_ROOT") != NULL) {
			root = 1;
		} else {
			root = 0;
		}
	}
}

void check_uid(void) {
	if (start == 0) {
		start = time(NULL);
		if (debug) fprintf(stderr, "START: %d\n", start);
		return;
	} else if (changed_uid == 0) {
		if (saw_fonts || time(NULL) > start + 20) {
			if (getenv("XDUMMY_UID")) {
				int uid = atoi(getenv("XDUMMY_UID"));
				if (debug) fprintf(stderr, "SETREUID: %d\n", uid);
				if (uid >= 0) {
					setreuid(uid, -1);
				}
			}
			changed_uid = 1;
		}
	}
}

#define CHECKIT if (debug < 0) check_debug(); \
		if (root  < 0) check_root(); \
		check_uid();

static void set_tmpdir(void) {
	char *s;
	static int didset = 0;
	if (didset) {
		return;
	}
	s = getenv("XDUMMY_TMPDIR");
	if (! s) {
		s = "/tmp";
	}
	tmpdir[0] = '\0';
	strcat(tmpdir, s);
	strcat(tmpdir, "/");
	didset = 1;
}

static char *tmpdir_path(const char *path) {
	char *str;
	set_tmpdir();
	strcpy(str2, path);
	str = str2;
	while (*str) {
		if (*str == '/') {
			*str = '_';
		}
		str++;
	}
	strcpy(str1, tmpdir);
	strcat(str1, str2);
	return str1;
}

int open(const char *pathname, int flags, unsigned short mode) {
	int fd;
	char *store_dev = NULL;
	static int (*real_open)(const char *, int , unsigned short) = NULL;

	CHECKIT
	if (! real_open) {
		real_open = (int (*)(const char *, int , unsigned short))
			dlsym(RTLD_NEXT, "open");
	}

	if (! root) {
		if (!strcmp(pathname, "/dev/mem")) {
			;
		} else if (!strcmp(pathname, "/dev/tty")) {
			;
		} else if (strstr(pathname, "/dev") == pathname) {
			store_dev = strdup(pathname);
			pathname = tmpdir_path(pathname);
			if (debug) fprintf(stderr, "OPEN: -> %s\n", pathname);
			fd = real_open(pathname, O_WRONLY|O_CREAT, 0777);
			close(fd);
		}
	}

	fd = real_open(pathname, flags, mode);

	if (debug) fprintf(stderr, "OPEN: %s %d %d fd=%d\n",
	    pathname, flags, mode, fd);

	if (! root) {
		if (store_dev && fd < 256) {
			if (fd < 256) {
				strcpy(devs[fd], store_dev);
			}
			free(store_dev);
		}
	}

	return(fd);
}

int open64(const char *pathname, int flags, unsigned short mode) {
	int fd;

	CHECKIT
	if (debug) fprintf(stderr, "OPEN64: %s %d %d\n", pathname, flags, mode);

	fd = open(pathname, flags, mode);
	return(fd);
}

FILE *fopen(const char *pathname, const char *mode) {
	static FILE* (*real_fopen)(const char *, const char *) = NULL;
	char *str;

	if (! saw_fonts) {
		if (strstr(pathname, "/fonts/")) {
			if (strstr(pathname, "fonts.dir")) {
				saw_fonts = 1;
			} else if (strstr(pathname, "fonts.alias")) {
				saw_fonts = 1;
			}
		}
	}

	CHECKIT
	if (! real_fopen) {
		real_fopen = (FILE* (*)(const char *, const char *))
			dlsym(RTLD_NEXT, "fopen");
	}
	if (debug) fprintf(stderr, "FOPEN: %s %s\n", pathname, mode);

	if (root) {
		return(real_fopen(pathname, mode));
	}

	str = (char *) pathname;
	if (strstr(pathname, "/var/log") == pathname) {
		str = tmpdir_path(pathname);
		if (debug) fprintf(stderr, "FOPEN: -> %s\n", str);
	}

}


#define RETURN0 if (debug) \
	{fprintf(stderr, "IOCTL: covered %d 0x%x\n", fd, req);} return 0;
#define RETURN1 if (debug) \
	{fprintf(stderr, "IOCTL: covered %d 0x%x\n", fd, req);} return -1;

int ioctl(int fd, int req, void *ptr) {
	static int closed_xf86Info_consoleFd = 0;
	static int (*real_ioctl)(int, int , void *) = NULL;

	CHECKIT
	if (! real_ioctl) {
		real_ioctl = (int (*)(int, int , void *))
			dlsym(RTLD_NEXT, "open");
	}
	if (debug) fprintf(stderr, "IOCTL: %d 0x%x %p\n", fd, req, ptr);

	/* based on xorg-x11-6.8.1-dualhead.patch */
	if (req == VT_GETMODE) {
		/* close(xf86Info.consoleFd) */
		if (0 && ! closed_xf86Info_consoleFd) {
			/* I think better not to close it... */
			close(fd);
			closed_xf86Info_consoleFd = 1;
		}
		RETURN0
	} else if (req == VT_SETMODE) {
		RETURN0
	} else if (req == VT_GETSTATE) {
		RETURN0
	} else if (req == KDSETMODE) {
		RETURN0
	} else if (req == KDSETLED) {
		RETURN0
	} else if (req == KDGKBMODE) {
		RETURN0
	} else if (req == VT_ACTIVATE) {
		RETURN0
	} else if (req == VT_WAITACTIVE) {
		RETURN0
	} else if (req == VT_RELDISP) {
		if (ptr == (void *) 1) {
			RETURN1
		} else if (ptr == (void *) VT_ACKACQ) {
			RETURN0
		}
	}

	return(real_ioctl(fd, req, ptr));
}

typedef void (*sighandler_t)(int);
#define SIGUSR1       10
#define SIG_DFL       ((sighandler_t)0)

sighandler_t signal(int signum, sighandler_t handler) {
	static sighandler_t (*real_signal)(int, sighandler_t) = NULL;

	CHECKIT
	if (! real_signal) {
		real_signal = (sighandler_t (*)(int, sighandler_t))
			dlsym(RTLD_NEXT, "signal");
	}

	if (debug) fprintf(stderr, "SIGNAL: %d %p\n", signum, handler);

	if (signum == SIGUSR1) {
		if (debug) fprintf(stderr, "SIGNAL: skip SIGUSR1\n");
		return SIG_DFL;
	}
	
	return(real_signal(signum, handler));
}

int close(int fd) {
	static int (*real_close)(int) = NULL;

	CHECKIT
	if (! real_close) {
		real_close = (int (*)(int)) dlsym(RTLD_NEXT, "close");
	}

	if (debug) fprintf(stderr, "CLOSE: %d\n", fd);
	if (! root) {
		if (fd < 256) {
			devs[fd][0] = '\0';
		}
	}
	return(real_close(fd));
}

struct stat {
	int foo;
};

int stat(const char *path, struct stat *buf) {
	static int (*real_stat)(const char *, struct stat *) = NULL;

	CHECKIT
	if (! real_stat) {
		real_stat = (int (*)(const char *, struct stat *))
			dlsym(RTLD_NEXT, "stat");
	}

	if (debug) fprintf(stderr, "STAT: %s\n", path);

	return(real_stat(path, buf));
}

int stat64(const char *path, struct stat *buf) {
	static int (*real_stat64)(const char *, struct stat *) = NULL;

	CHECKIT
	if (! real_stat64) {
		real_stat64 = (int (*)(const char *, struct stat *))
			dlsym(RTLD_NEXT, "stat64");
	}

	if (debug) fprintf(stderr, "STAT64: %s\n", path);

	return(real_stat64(path, buf));
}

/*
 * Note: the following just call the real function if root is
 * true.  They will be used if -nonroot is ever figured out.
 */

int chown(const char *path, uid_t owner, gid_t group) {
	static int (*real_chown)(const char *, uid_t, gid_t) = NULL;

	CHECKIT
	if (! real_chown) {
		real_chown = (int (*)(const char *, uid_t, gid_t))
			dlsym(RTLD_NEXT, "chown");
	}

	if (root) {
		return(real_chown(path, owner, group));
	}

	if (debug) fprintf(stderr, "CHOWN: %s %d %d\n", path, owner, group);

	if (strstr(path, "/dev") == path) {
		if (debug) fprintf(stderr, "CHOWN: return 0\n");
		return 0;
	}

	return(real_chown(path, owner, group));
}


int ioperm(unsigned long from, unsigned long num, int turn_on) {
	static int (*real_ioperm)(unsigned long, unsigned long, int) = NULL;
	CHECKIT
	if (! real_ioperm) {
		real_ioperm = (int (*)(unsigned long, unsigned long, int))
			dlsym(RTLD_NEXT, "ioperm");
	}
	if (root) {
		return(real_ioperm(from, num, turn_on));
	}
	return 0;
}

int iopl(int level) {
	static int (*real_iopl)(int) = NULL;
	CHECKIT
	if (! real_iopl) {
		real_iopl = (int (*)(int)) dlsym(RTLD_NEXT, "iopl");
	}
	if (root) {
		return(real_iopl(level));
	}
	return 0;
}

uid_t getuid(void) {
	static uid_t (*real_getuid)(void) = NULL;
	CHECKIT
	if (! real_getuid) {
		real_getuid = (uid_t (*)(void)) dlsym(RTLD_NEXT, "getuid");
	}
	if (root) {
		return(real_getuid());
	}
	if (debug) fprintf(stderr, "GETUID: 0\n");
	return 0;
}
uid_t geteuid(void) {
	static uid_t (*real_geteuid)(void) = NULL;
	CHECKIT
	if (! real_geteuid) {
		real_geteuid = (uid_t (*)(void)) dlsym(RTLD_NEXT, "geteuid");
	}
	if (root) {
		return(real_geteuid());
	}
	if (debug) fprintf(stderr, "GETEUID: 0\n");
	return 0;
}
uid_t getuid32(void) {
	static uid_t (*real_getuid32)(void) = NULL;
	CHECKIT
	if (! real_getuid32) {
		real_getuid32 = (uid_t (*)(void)) dlsym(RTLD_NEXT, "getuid32");
	}
	if (root) {
		return(real_getuid32());
	}
	if (debug) fprintf(stderr, "GETUID32: 0\n");
	return 0;
}
uid_t geteuid32(void) {
	static uid_t (*real_geteuid32)(void) = NULL;
	CHECKIT
	if (! real_geteuid32) {
		real_geteuid32 = (uid_t (*)(void)) dlsym(RTLD_NEXT, "geteuid32");
	}
	if (root) {
		return(real_geteuid32());
	}
	if (debug) fprintf(stderr, "GETEUID32: 0\n");
	return 0;
}

gid_t getgid(void) {
	static gid_t (*real_getgid)(void) = NULL;
	CHECKIT
	if (! real_getgid) {
		real_getgid = (gid_t (*)(void)) dlsym(RTLD_NEXT, "getgid");
	}
	if (root) {
		return(real_getgid());
	}
	if (debug) fprintf(stderr, "GETGID: 0\n");
	return 0;
}
gid_t getegid(void) {
	static gid_t (*real_getegid)(void) = NULL;
	CHECKIT
	if (! real_getegid) {
		real_getegid = (gid_t (*)(void)) dlsym(RTLD_NEXT, "getegid");
	}
	if (root) {
		return(real_getegid());
	}
	if (debug) fprintf(stderr, "GETEGID: 0\n");
	return 0;
}
gid_t getgid32(void) {
	static gid_t (*real_getgid32)(void) = NULL;
	CHECKIT
	if (! real_getgid32) {
		real_getgid32 = (gid_t (*)(void)) dlsym(RTLD_NEXT, "getgid32");
	}
	if (root) {
		return(real_getgid32());
	}
	if (debug) fprintf(stderr, "GETGID32: 0\n");
	return 0;
}
gid_t getegid32(void) {
	static gid_t (*real_getegid32)(void) = NULL;
	CHECKIT
	if (! real_getegid32) {
		real_getegid32 = (gid_t (*)(void)) dlsym(RTLD_NEXT, "getegid32");
	}
	if (root) {
		return(real_getegid32());
	}
	if (debug) fprintf(stderr, "GETEGID32: 0\n");
	return 0;
}

#if 0
int xf86PathIsSafe(char *path) {
	fprintf(stderr, "xf86pathIsSafe: %s\n", path);
	return 1;
}
#endif

#if 0
int strcmp(const char *s1, const char *s2) {
	static int (*real_strcmp)(const char *, const char *) = NULL;
	CHECKIT
	if (! real_strcmp) {
		real_strcmp = (int (*)(const char *, const char *)) dlsym(RTLD_NEXT, "strcmp");
	}
	if (debug) fprintf(stderr, "STRCMP: '%s' '%s'\n", s1, s2);
	return(real_strcmp(s1, s2));
}
#endif

#code_end
}