#!/usr/bin/perl

use Sys::Syslog;

#
# Place version number (in both forms) here
#

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

$Lynx = "/usr/bin/lynx -dump";
$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
chdir "$SophosRoot/bin/$VDLDir";
opendir(LIBDIR, ".") || &BailOut("Cannot open Sophos/lib directory");
foreach $vdlname (sort readdir(LIBDIR)) {
	next unless $vdlname =~ /^vdl-(\d+)\.(\d+)\.dat$/;
	$MajorVer = $1;
	$MinorVer = $2;
}
closedir(LIBDIR);
&BailOut("Could not calculate Sophos version number")
  unless defined($MajorVer) && defined($MinorVer);
$SophosVersion = "$MajorVer$MinorVer";
$VDLVersion = "$MajorVer.$MinorVer";

# Derive other filenames and URLs from this
$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);
#print "Sophos Version is $SophosVersion\n";
#print "VDL Version    is $VDLVersion\n";

# 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 directory for today
umask 0022;
mkdir $IDEDir, 0755;

chdir $IDEDir or &BailOut("Cannot cd $IDEDir, $!");

# Fetch and unpack the IDE zip file from Sophos
$result = system("$Lynx $URL > $ZipName");
&BailOut("Lynx failed with error return " . ($result>>8) . "\n") if $result>>8;
$result = system("$Unzip $ZipName");
&BailOut("Unzip failed with error return " . ($result>>8) . "\n") if $result>>8;
symlink("$VDLDir/vdl-$VDLVersion.dat", "vdl.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";
	flock(LOCK, $LOCK_UN);
	close LOCK;
}