#!/usr/bin/perl
#
# List the most frequent messages in the apache error log file
#
# Usage: errstats.pl error_log
#
# Earl Fogel, February 2000

$mincount = 5;		# ignore errors which occur fewer times than this
$minpercent = 0.25;	# ignore errors which account for less than this
			# percent of the total
$skipimages = 0;	# include gif,jpg,ico... files in report
$DocumentRoot = "/var/www/html";

while ($_ = $ARGV[0], /^-/) {
   shift;
   last if /^--$/;
   /^-image/ && ($skipimages = 1) && next;
   /^-mincount=(.*)/ && ($mincount=$1) && next;
   /^-minpercent=(.*)/ && ($minpercent=$1) && next;
   &usage;
}

while (<>) {

    next if /\[notice\]/;	# we're only interested in errors

    chop;
    s/^\[.*?\] *//;		# throw away [date]
    s/^\[.*?\] *//;		# throw away [warning|error|...]
    my $client = $1 if s/^\[client ([^\]]+)\] *//;
    s#$DocumentRoot##o;		# throw away Document Root

    #
    # some common types of errors
    #
    if (/^access to (.*) failed for .* reason: (.* does not exist)/
         || /^File does not exist: (.*)/) {
	my $file = $1;
	next if $skipimages && $file =~ /\.(gif|jpg|jpeg|ico)$/i;
	$badfile{$file}++;	# file does not exist

    } elsif (/^access to (.*) failed for .* reason: (script not found)/
         || /^script not found or unable to stat: (.*)/) {
	$badscript{"$1"}++;	# script does not exist

    } elsif (/^access to (.*) failed for .* reason: (malformed .* script)/) {
	$errscript{"$1"}++;	# bad header from script

    } elsif (/^access to (.*) failed for .* reason: krb[^:]*: (.*)/) {
	$badperms{"$1 Kerberos $2"}++;	# kerberos permission problems

    } elsif (/^.*Permission denied: (.*)/) {
	$badperms{"$1"}++;	# permission problems

    } else {
	s/ for \d+\.\d+\.\d+\.\d+//;
	s/^\d+\.\d+\.\d+\.\d+ +//;
	s/(lost connection to client).*/$1/;
	s/, referer: .*//;
	$err{"$_"}++;
    }
}

&DisplayTop(*badfile,"File does not exist");
&DisplayTop(*badscript,"Script not found or unable to stat");
&DisplayTop(*errscript,"Malformed header from script");
&DisplayTop(*badperms,"Bad permissions");
&DisplayTop(*err,"Other errors");

sub DisplayTop {
local(*hash,$heading) = @_;
my($n,$limit,$msg,$total);

    if (defined(%hash)) {
	$n = keys(%hash);
        foreach $msg (keys(%hash)) {
	    $total += $hash{$msg};
	    delete $hash{$msg} if $hash{$msg} < $mincount;
        }
        foreach $msg (keys(%hash)) {
	    delete $hash{$msg} if $hash{$msg} < $total * ($minpercent / 100);
        }
	$limit = keys(%hash);
        return unless $limit;
	print "\n$heading (displaying top $limit of $n lines):\n";
	foreach $msg (sort {$hash{$b}-$hash{$a}} keys(%hash)) {
	    printf("%5d %s\n",$hash{$msg},$msg);
	}
    }
}