#!/usr/bin/perl

#   MailScanner - SMTP E-Mail Virus Scanner
#   Copyright (C) 2001  Julian Field
#
#   This program 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 program 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 program; if not, write to the Free Software
#   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
#
#   The author, Julian Field, can be contacted by email at
#      Jules@JulianField.net
#   or by paper mail at
#      Julian Field
#      Dept of Electronics & Computer Science
#      University of Southampton
#      Southampton
#      SO17 1BJ
#      United Kingdom
#

#
# Vexira updater. Original code by Julian Field. Timeout code by
# Alessandro Bianchi. Timeout code is not perfect but should be okay.
#

use Sys::Syslog;

# If you have a web proxy or cache server, put its value in the next line
# in the syntax "full.host.name:port".
$HTTPproxy = "";

$PackageDir = shift || "/usr/local/vexira";
$Signatures    = "vexira8.vdb";
$SignaturesNew = "vexira8.vdb.new";
$DownloadPath = "ftp://upd.vexira.com/pub/vexira/vdb.8/vexira8.vdb";

$LockFile = "/tmp/VexiraBusy.lock";

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

eval { Sys::Syslog::setlogsock('unix'); }; # This may fail!
Sys::Syslog::openlog("Vexira-autoupdate", 'pid, nowait', 'mail');

#
# Check we can find all the external programs we need
#
$result = system("wget --version < /dev/null > /dev/null 2>&1");
BailOut("Could not find wget on your path. Please install it or fix your path")
  if $result==127;

#
# Download update information from the update server
#
$SIG{ALRM} = sub { die "timeout" };

eval {
  # Timeout prevention
  alarm 300;

  $result = system("wget --output-document=$PackageDir/$SignaturesNew " .
                   "--tries=3 '$DownloadPath' > /dev/null 2>&1");
  BailOut("wget command failed. You need the latest version installed, $!")
    if $result==127;
  BailOut("Updates download from $DownloadPath failed. " .
          "Suspect server could not be reached, $!")
    if $result!=0;

  # Only do this if it succeeded within the timeout
  &LockVexira;
  unlink "$PackageDir/$Signatures";
  rename "$PackageDir/$SignaturesNew", "$PackageDir/$Signatures";
  &UnlockVexira;
  alarm 0;
};

if ($@) {
  if ($@ =~ /timeout/) {
    # We timed out!
    Sys::Syslog::syslog('err', "WARNING: Vexira update timed out");
    alarm 0;
    unlink "$PackageDir/$SignaturesNew";
  } else {
    Sys::Syslog::syslog('err', "Vexira update cannot be run");
  }
} else {
  Sys::Syslog::syslog('notice', "Vexira update completed");
}

Sys::Syslog::closelog();
exit 0;

sub BailOut {
  Sys::Syslog::syslog('err', @_);
  Sys::Syslog::closelog();
  warn "@_, $!";
  exit 1;
}

sub LockVexira {
  open(LOCK, ">$LockFile") or return;
  flock(LOCK, $LOCK_EX);
  print LOCK "Locked for updating Vexira definitions by $$\n";
}

sub UnlockVexira {
  print LOCK "Unlocked after updating Vexira definitions by $$\n";
  unlink $LockFile;
  flock(LOCK, $LOCK_UN);
  close LOCK;
}