#!/usr/bin/perl

use Sys::Syslog;

$SophosRoot = shift || "/usr/local/Sophos";
$IDELink    = "$SophosRoot/ide";
$VDLDir     = "../lib";

#$Lynx = "/usr/local/bin/lynx -dump";
$Lynx = "/usr/bin/wget -q -O-"; # On Linux use this
$Unzip = "/usr/bin/unzip -joqq";
$rm = "/bin/rm";
$LockFile = "/tmp/SophosBusy.lock";

$LOCK_SH = 1;
$LOCK_EX = 2;
$LOCK_NB = 4;
$LOCK_UN = 8;

Sys::Syslog::openlog("Sophos-autoupdate", 'pid, nowait', 'mail');

# Work out the current VDL (and hence Sophos Sweep) version number
unless (chdir "$SophosRoot/bin/$VDLDir") {
  &BailOut("Could not find directory \"$SophosRoot/bin/$VDLDir\"");
}

opendir(LIBDIR, ".") || &BailOut("Cannot open Sophos/lib directory");
foreach $vdlname (sort readdir(LIBDIR)) {
	next unless $vdlname =~ /^vdl-(\d+)\.(\d+)([a-zA-Z]*)\.dat$/;
	$MajorVer = $1;
	$MinorVer = $2;
        $NSVFlag  = $3;
}
closedir(LIBDIR);
&BailOut("Could not calculate Sophos version number")
  unless defined($MajorVer) && defined($MinorVer);
$SophosVersion = "$MajorVer$MinorVer";
$VDLVersion = "$MajorVer.$MinorVer";

# Derive other variables, filenames and URLs from the version numbers
$ZipName = $SophosVersion . "_ides.zip";
$URL  = "http://www.sophos.com/downloads/ide/$ZipName";

($min,$hour,$date,$month,$year) = (localtime)[1,2,3,4,5];
$month++;
$year+=1900;
$IDEDir = "$SophosRoot/$SophosVersion." . sprintf("%04d%02d%02d%02d%02d", $year, $month, $date, $hour, $min);

# If the directory already exists, then we have already done the update
# for today, so quietly exit.
Sys::Syslog::syslog('info', "Sophos already up-to-date"),exit 0 if -d $IDEDir;

# Create the IDE files directory
umask 0022;
mkdir $IDEDir, 0755;
chdir $IDEDir or &BailOut("Cannot cd $IDEDir, $!");

# Fetch and unpack the IDE zip file from Sophos
#print STDERR "URL is $URL\n";
$result = system("$Lynx $URL > $ZipName");
if (($result>>8)==1) {
  Sys::Syslog::syslog('err', "Your Sophos installation may be too old. Please install the latest release of Sophos");
  print STDERR "Your Sophos installation may be too old. Please install the latest release of Sophos";
}
&BailOut("Lynx failed with error return " . ($result>>8) . "\n") if $result>>8;

$result = system("$Unzip $ZipName");
if ($result>>8) {
  Sys::Syslog::syslog('err', "Unzipping the new Sophos IDE files failed. This may well be because your Sophos installation is too old. Please install the latest release of Sophos");
  print STDERR "Unzipping the new Sophos IDE files failed. This may well be because your Sophos installation is too old. Please install the latest release of Sophos";
  &BailOut("Unzip failed with error return " . ($result>>8) . "\n");
}

symlink("$VDLDir/vdl-$VDLVersion$NSVFlag.dat", "vdl.dat");

# Add the new vdl*.vdb files if they are there
foreach $number (1..99) {
  $string = "vdl" . sprintf("%02d", $number) . ".vdb";
  symlink("$VDLDir/$string", $string) if -f "$VDLDir/$string";
}

# Add the new swpmess.dat and svext.dat files too
symlink("$VDLDir/swpmess.dat", "swpmess.dat") if -f "$VDLDir/swpmess.dat";
symlink("$VDLDir/svext.dat", "svext.dat") if -f "$VDLDir/svext.dat";

# Link in this new directory to Sophos
chdir $SophosRoot or &BailOut("Cannot cd $SophosRoot, $!");
$OldLinkTarget = readlink $IDELink;
&LockSophos();
unlink $IDELink if -l $IDELink;
symlink $IDEDir, $IDELink;
&UnlockSophos();
system("$rm -rf $OldLinkTarget") if defined $OldLinkTarget && -e $OldLinkTarget;
Sys::Syslog::syslog('info', "Sophos successfully updated in $IDEDir");
Sys::Syslog::closelog();
exit 0;

sub BailOut {
	Sys::Syslog::syslog('err', @_);
	Sys::Syslog::closelog();
	warn "@_, $!";
	chdir $SophosRoot or die "Cannot cd $SophosRoot, $!";
	system("$rm -rf $IDEDir") if -d $IDEDir;
	exit 1;
}

sub LockSophos {
	open(LOCK, ">$LockFile") or return;
	flock(LOCK, $LOCK_EX);
	print LOCK "Locked for updating Sophos IDE files by $$\n";
}

sub UnlockSophos {
	print LOCK "Unlocked after updating Sophos IDE files by $$\n";
	unlink $LockFile;
	flock(LOCK, $LOCK_UN);
	close LOCK;
}