#!/usr/bin/perl
# -*- Mode: perl -*-
#template by ~tconnors/bin/newplscript
#Sat Dec 20 14:56:09 EST 2003

# $Revision: 1.2 $ $Date: 2004/02/01 10:00:17 $
# $Id: mailoops,v 1.2 2004/02/01 10:00:17 tconnors Exp $
# $Header: /home/office/tconnors/cvsroot/bin/mailoops,v 1.2 2004/02/01 10:00:17 tconnors Exp $
# $RCSfile: mailoops,v $

# This program tail -f's /var/log/syslog, and mails any OOPs of BUGs to root
use strict;
use warnings;

sub usageerror {
  my ($error)=(@_);
  if (defined($error)) {
    print STDERR "Usage error: $error\n";
  }
  usage(1);
}

sub usage {
  my ($exit)=(@_);
  print STDERR "Usage: $0 [--file|-f <syslogfile>]\n";
  $exit=defined($exit) ? $exit : 0;
  exit $exit;
}

my ($syslog);

sub parseinput {
  sub setsyslog {
    $syslog=shift (@ARGV) || usageerror("no syslog file supplied");
  }
  $syslog="/var/log/syslog";

  while ($_= shift (@ARGV)) {
    /^(--file|-f)$/ && setsyslog() ||
    /^--help$/ && usage() ||
    /^-/ && usageerror("Unrecognised switch: $_") ||
    usageerror("Unrecognised option: $_");
  }
}

#########################

parseinput();

open(FH,"tail -n 10000 --follow=name \"$syslog\"|") or die "Can't open tail -f $syslog for read.";

my ($oopsing, $lastoopsing, $oopstime, $line, $then, $thenstr, $currenthost, $timeout, $noline, @last, $oopstimestr);
use POSIX;

chomp ($currenthost=`hostname`);
$oopsing=$lastoopsing=0;
@last=();
$| = 1;
$timeout=5;
while (1) {
  $noline=0;
  #set up alarm;
  eval {
    local $SIG{ALRM} = sub { die "alarm\n" }; # NB: \n required
    alarm $timeout;
    chomp ($_=<FH>);
    alarm 0;
  };
  #detect alarm;
  if ($@) {
    die unless $@ eq "alarm\n";   # propagate unexpected errors
    $noline=1;
    print "#";
  } else {
    print ".";
  }
  /kernel: (Unable to handle kernel paging request|Badness in)/ && do {
    $oopsing=1;
    ( $thenstr = $_ ) =~ s/^([^ ]*  *[^ ]*  *[^ ]*) .*/$1/ ;
    chomp ($then=`date -d "$thenstr" +%s`);
    $oopstime=$then;
    $oopstimestr=$thenstr;
  };
  if ($oopsing) {
    if (!$lastoopsing) {
      print "\nOops or BUG detected...";
      print "\nOpening mail file";
      open (MAIL, "|mail -s \"Oops or BUG detected at $oopstimestr\" root") or die "can't open mail for writing to";
      foreach $line (@last) {
        print "!";
        ( $thenstr = $line ) =~ s/^([^ ]*  *[^ ]*  *[^ ]*) .*/$1/;
        chomp ($then=`date -d "$thenstr" +%s`);
        if ($then>$oopstime) {
          last;
        } elsif ($oopstime - $then < 60) { #find everything in the past that heppened within 60 seconds of the oops/bug
          print MAIL "$line\n";
        }
      }
    }
    ( $thenstr = $_ ) =~ s/^([^ ]*  *[^ ]*  *[^ ]*) .*/$1/ ;
    chomp ($then=`date -d "$thenstr" +%s`);
#    print "$thenstr -> $then\n";
    if (!$noline && $then-$oopstime < 60) { #keep printing until a minute has elapsed from the most recent oops
      print MAIL "$_\n";
    } else {
      $oopsing=0;
      print "\nClosing mail file";
      close MAIL;
    }
    @last=();
  } elsif (!$noline) {
    push @last, $_;
  }
  $lastoopsing=$oopsing;
}


close FH;