#!/usr/local/perl/bin/perl
#
# Copyright (C) 1999 AT&T Laboratories Cambridge. All Rights Reserved.
#
# This is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This software is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this software; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
# USA.
#
#
# vncserver - wrapper script to start an X VNC server.
#
#
# First make sure we're operating in a sane environment.
#
&SanityCheck();
#
# Global variables. You may want to configure some of these for 
your site.
#
$geometry = "1024x768";
$depth = 8;
$desktopName = "X";
$vncClasses = "/usr/local/vnc/classes";
$vncUserDir = "$ENV{HOME}/.vnc";
$xauthorityFile = "$ENV{HOME}/.Xauthority";
$defaultXStartup
= ("#!/bin/sh\n\n".
"xrdb \$HOME/.Xresources\n".
"xsetroot -solid grey\n".
"xterm -geometry 80x24+10+10 -ls -title \"\$VNCDESKTOP 
Desktop\" &\n".
"twm &\n");
chop($host = `uname -n`);# Check command line options
&ParseOptions("-geometry",1,"-depth",1,"-pixelformat",1,"-name",1,"-kill",1,
"-help",0,"-h",0,"--help",0);
&Usage() if ($opt{'-help'} || $opt{'-h'} || $opt{'--help'});
&Kill() if ($opt{'-kill'});
# Uncomment this line if you want default geometry, depth and pixelformat
# to match the current X display:
# &GetXDisplayDefaults();
if ($opt{'-geometry'}) {
	$geometry = $opt{'-geometry'};
}
if ($opt{'-depth'}) {
	$depth = $opt{'-depth'};
	$pixelformat = "";
}
if ($opt{'-pixelformat'}) {
	$pixelformat = $opt{'-pixelformat'};
}
&CheckGeometryAndDepth();
if ($opt{'-name'}) {
	$desktopName = $opt{'-name'};
}# Create the user's vnc directory if necessary.
if (!(-e $vncUserDir)) {
	if (!mkdir($vncUserDir,0755)) {
		die "$prog: Could not create $vncUserDir.\n";
	}
}

# Make sure the user has a password.
($z,$z,$mode) = stat("$vncUserDir/passwd");
if (!(-e "$vncUserDir/passwd") || ($mode & 077)) {
	warn "\nYou will require a password to access your desktops.\n\n";
	system("vncpasswd $vncUserDir/passwd"); 
	if (($? >> 8) != 0) {
		exit 1;
	}
}
# Find display number.
if ((@ARGV > 0) && ($ARGV[0] =~ /^:(\d+)$/)) {
	$displayNumber = $1;
	shift(@ARGV);
	if (!&CheckDisplayNumber($displayNumber)) {
		die "A VNC server is already running as :$displayNumber\n";
	}
} elsif ((@ARGV > 0) && ($ARGV[0] !~ /^-/)) {
	&Usage();
} else {
	$displayNumber = &GetDisplayNumber();
}
$vncPort = 5900 + $displayNumber;
$desktopLog = "$vncUserDir/$host:$displayNumber.log";
unlink($desktopLog);
# Make an X server cookie - use as the seed the sum of the current 
time, our
# PID and part of the encrypted form of the password. Ideally we'd 
use
# /dev/urandom, but that's only available on Linux.
srand(time+$$+unpack("L",`cat $vncUserDir/passwd`));
$cookie = "";
for (1..16) {
	$cookie .= sprintf("%02x", int(rand(256)));
}

system("xauth -f $xauthorityFile add $host:$displayNumber . 
$cookie");
system("xauth -f $xauthorityFile add $host/unix:$displayNumber 
. $cookie"); 
# Now start the X VNC Server
$cmd = "Xvnc :$displayNumber";
$cmd .= " -desktop " . "edString($desktopName);
$cmd .= " -httpd $vncClasses";
$cmd .= " -auth $xauthorityFile";
$cmd .= " -geometry $geometry" if ($geometry);
$cmd .= " -depth $depth" if ($depth);
$cmd .= " -pixelformat $pixelformat" if ($pixelformat);
$cmd .= " -rfbwait 120000";
$cmd .= " -rfbauth $vncUserDir/passwd";
$cmd .= " -rfbport $vncPort";
# Add font path and color database stuff here, e.g.:
#
# $cmd .= " -fp /usr/lib/X11/fonts/misc/,/usr/lib/X11/fonts/75dpi/";
# $cmd .= " -co /usr/lib/X11/rgb";
#
foreach $arg (@ARGV) {
	$cmd .= " " . "edString($arg);
}
$cmd .= " >> " . "edString($desktopLog) . " 
2>&1";
# Run $cmd and record the process ID.
$pidFile = "$vncUserDir/$host:$displayNumber.pid";
system("$cmd & echo \$! >$pidFile");
# Give Xvnc a chance to start up
sleep(3); 
warn "\nNew '$desktopName' desktop is $host:$displayNumber\n\n";
# Create the user's xstartup script if necessary.
if (!(-e "$vncUserDir/xstartup")) {
	warn "Creating default startup script $vncUserDir/xstartup\n";
open(XSTARTUP, ">$vncUserDir/xstartup");
print XSTARTUP $defaultXStartup;
close(XSTARTUP);
chmod 0755, "$vncUserDir/xstartup";
}
# Run the X startup script.
warn "Starting applications specified in $vncUserDir/xstartup\n";
warn "Log file is $desktopLog\n\n";
# If the unix domain socket exists then use that (DISPLAY=:n) otherwise 
use
# TCP (DISPLAY=host:n)
if (-e "/tmp/.X11-unix/X$displayNumber") {
	$ENV{DISPLAY}= ":$displayNumber";
} else {
	$ENV{DISPLAY}= "$host:$displayNumber";
}
$ENV{VNCDESKTOP}= $desktopName;
system("$vncUserDir/xstartup >> " . "edString($desktopLog) 
. " 2>&1 &");
exit;################################################################
#
# CheckGeometryAndDepth simply makes sure that the geometry and 
depth values
# are sensible.
#
sub CheckGeometryAndDepth
{
	if ($geometry =~ /^(\d+)x(\d+)$/) {
		$width = $1; $height = $2;
		if (($width<1) || ($height<1)) {
			die "$prog: geometry $geometry is invalid\n";
		}
		while (($width % 4)!=0) {
			$width = $width + 1;
		}
		while (($height % 2)!=0) {
			$height = $height + 1;
		}
		$geometry = "${width}x$height";
	} else {
		die "$prog: geometry $geometry is invalid\n";
	}
	if (($depth < 8) || ($depth > 32)) {
		die "Depth must be between 8 and 32\n";
	}
}#
# GetDisplayNumber gets the lowest available display number. A display number
# n is taken if something is listening on the VNC server port (5900+n) or the
# X server port (6000+n).
#
sub GetDisplayNumber
{
	foreach $n (1..99) {
		if (&CheckDisplayNumber($n)) {
			return $n+0; # Bruce Mah's workaround for bug in perl 5.005_02
		}
	}

	die "$prog: no free display number on $host.\n";
}#
# CheckDisplayNumber checks if the given display number is available. 
A
# display number n is taken if something is listening on the VNC 
server port
# (5900+n) or the X server port (6000+n).
#
sub CheckDisplayNumber
{
	local ($n) = @_;
	socket(S, $AF_INET, $SOCK_STREAM, 0) || die "$prog: socket 
	failed: $!\n";
	eval 'setsockopt(S, &SOL_SOCKET, &SO_REUSEADDR, pack("l", 1))';
	if (!bind(S, pack('S n x12', $AF_INET, 6000 + $n))) {
		close(S);
		return 0;
	}
	close(S);
	socket(S, $AF_INET, $SOCK_STREAM, 0) || die "$prog: socket 
	failed: $!\n";
	eval 'setsockopt(S, &SOL_SOCKET, &SO_REUSEADDR, pack("l", 1))';
	if (!bind(S, pack('S n x12', $AF_INET, 5900 + $n))) {
		close(S);
		return 0;
	}
	close(S);
	if (-e "/tmp/.X$n-lock") {
		warn "\nWarning: $host:$n is taken because of /tmp/.X$n-lock\n";
		warn "Remove this file if there is no X server $host:$n\n";
		return 0;
	}
	if (-e "/tmp/.X11-unix/X$n") {
		warn "\nWarning: $host:$n is taken because of /tmp/.X11-unix/X$n\n";
		warn "Remove this file if there is no X server $host:$n\n";
		return 0;
	}
	return 1;
}#
# GetXDisplayDefaults uses xdpyinfo to find out the geometry, depth and pixel
# format of the current X display being used. If successful, it sets the
# options as appropriate so that the X VNC server will use the same settings
# (minus an allowance for window manager decorations on the geometry).  Using
# the same depth and pixel format means that the VNC server won't have to
# translate pixels when the desktop is being viewed on this X display (for
# TrueColor displays anyway).
#
sub GetXDisplayDefaults
{
	local (@lines, @matchlines, $width, $height, $defaultVisualId, $i, $red, $green, $blue);
	$wmDecorationWidth = 4; # a guess at typical size for window manager
	$wmDecorationHeight = 24; # decoration size
	return if (!defined($ENV{DISPLAY}));
	@lines = `xdpyinfo 2>/dev/null`;
	return if ($? != 0);
	@matchlines = grep(/dimensions/, @lines);
	if (@matchlines) {
		($width, $height) = ($matchlines[0] =~ /(\d+)x(\d+) pixels/);
		$width -= $wmDecorationWidth;
		$height -= $wmDecorationHeight;
		$geometry = "${width}x$height";
	}
	@matchlines = grep(/default visual id/, @lines);
	if (@matchlines) {
		($defaultVisualId) = ($matchlines[0] =~ /id:\s+(\S+)/);
		for ($i = 0; $i < @lines; $i++) {
			if ($lines[$i] =~ /^\s*visual id:\s+$defaultVisualId$/) {
				if (($lines[$i+1] !~ /TrueColor/) ||
				($lines[$i+2] !~ /depth/) ||
				($lines[$i+4] !~ /red, green, blue masks/))
				{
					return;
				}
				last;
			}
		}
		return if ($i >= @lines);
		($depth) = ($lines[$i+2] =~ /depth:\s+(\d+)/);
		($red,$green,$blue) = ($lines[$i+4] =~ /masks:\s+0x([0-9a-f]+), 0x([0-9a-f]+), 0x([0-9a-f]+)/);
		$red = hex($red);
		$green = hex($green);
		$blue = hex($blue);
		if ($red > $blue) {
			$red = int(log($red) / log(2)) - int(log($green) / log(2));
			$green = int(log($green) / log(2)) - int(log($blue) / log(2));
			$blue = int(log($blue) / log(2)) + 1;
			$pixelformat = "rgb$red$green$blue";
		} else {
			$blue = int(log($blue) / log(2)) - int(log($green) / log(2));
			$green = int(log($green) / log(2)) - int(log($red) / log(2));
			$red = int(log($red) / log(2)) + 1;
			$pixelformat = "bgr$blue$green$red";
		}
	}
}#
# quotedString returns a string which yields the original string 
when parsed
# by a shell.
#
sub quotedString
{
	local ($in) = @_;
	$in =~ s/\'/\'\"\'\"\'/g;
	return "'$in'";
}#
# removeSlashes turns slashes into underscores for use as a file 
name.
#
sub removeSlashes
{
	local ($in) = @_;
	$in =~ s|/|_|g;
	return "$in";
}#
# Usage
#
sub Usage
{
	die("\nusage: $prog [:] [-name ] [-depth ]\n".
	" [-geometry x]\n".
	" [-pixelformat rgbNNN|bgrNNN]\n".
	" ...\n\n".
	" $prog -kill \n\n");
}#
# Kill
#
sub Kill
{
	$opt{'-kill'} =~ s/(:\d+)\.\d+$/$1/; # e.g. turn :1.0 into :1
	if ($opt{'-kill'} =~ /^:\d+$/) {
		$pidFile = "$vncUserDir/$host$opt{'-kill'}.pid";
	} else {
		if ($opt{'-kill'} !~ /^$host:/) {
			die "\nCan't tell if $opt{'-kill'} is on $host\n".
			"Use -kill : instead\n\n";
		}
		$pidFile = "$vncUserDir/$opt{'-kill'}.pid";
	}
	if (! -r $pidFile) {
		die "\nCan't find file $pidFile\n".
		"You'll have to kill the Xvnc process manually\n\n";
	}
	$SIG{'HUP'} = 'IGNORE';
	chop($pid = `cat $pidFile`);
	warn "Killing Xvnc process ID $pid\n";
	system("kill $pid");
	unlink $pidFile;
	exit;
}#
# ParseOptions takes a list of possible options and a boolean indicating
# whether the option has a value following, and sets up an associative 
array
# %opt of the values of the options given on the command line. It 
removes all
# the arguments it uses from @ARGV and returns them in @optArgs.
#
sub ParseOptions
{
	local (@optval) = @_;
	local ($opt, @opts, %valFollows, @newargs);
	while (@optval) {
		$opt = shift(@optval);
		push(@opts,$opt);
		$valFollows{$opt} = shift(@optval);
	}
	@optArgs = ();
	%opt = ();
	arg: while (defined($arg = shift(@ARGV))) {
		foreach $opt (@opts) {
			if ($arg eq $opt) {
				push(@optArgs, $arg);
				if ($valFollows{$opt}) {
					if (@ARGV == 0) {
						&Usage();
					}
					$opt{$opt} = shift(@ARGV);
					push(@optArgs, $opt{$opt});
				} else {
					$opt{$opt} = 1;
				}
				next arg;
			}
		}
	push(@newargs,$arg);
	}
	@ARGV = @newargs;
}#
# Routine to make sure we're operating in a sane environment.
#
sub SanityCheck
{
	local ($cmd);
	#
	# Get the program name
	#
	($prog) = ($0 =~ m|([^/]+)$|);
	#
	# Check we have all the commands we'll need on the path.
	#
	cmd:
	foreach $cmd ("uname","xauth","Xvnc","vncpasswd") 
	{
		for (split(/:/,$ENV{PATH})) {
			if (-x "$_/$cmd") {
				next cmd;
			}
		}
		die "$prog: couldn't find \"$cmd\" on your PATH.\n";
	}
	#
	# Check the HOME environment variable is set
	#
	if (!defined($ENV{HOME})) {
		die "$prog: The HOME environment variable is not set.\n";
	}
	#
	# Find socket constants. 'use Socket' is a perl5-ism, so we wrap it in an
	# eval, and if it fails we try 'require "sys/socket.ph"'.  If this fails,
	# we just guess at the values. If you find perl moaning here, just
	# hard-code the values of AF_INET and SOCK_STREAM. You can find these out
	# for your platform by looking in /usr/include/sys/socket.h and related
	# files.
	#
	chop($os = `uname`);
	chop($osrev = `uname -r`);
	eval 'use Socket';
	if ($@) {
		eval 'require "sys/socket.ph"';
		if ($@) {
			if (($os eq "SunOS") && ($osrev !~ /^4/)) {
				$AF_INET = 2;
				$SOCK_STREAM = 2;
			} else {
				$AF_INET = 2;
				$SOCK_STREAM = 1;
			}
		} else {
			$AF_INET = &AF_INET;
			$SOCK_STREAM = &SOCK_STREAM;
		}
	} else {
		$AF_INET = &AF_INET;
		$SOCK_STREAM = &SOCK_STREAM;
	}
}