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#!/usr/bin/perl
#
# Licensed to the Apache Software Foundation (ASF) under one or more
# contributor license agreements. See the NOTICE file distributed with
# this work for additional information regarding copyright ownership.
# The ASF licenses this file to You under the Apache License, Version 2.0
# (the "License"); you may not use this file except in compliance with
# the License. You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
#
# logresolve.pl
#
# v 1.2 by robh @ imdb.com
#
# usage: logresolve.pl <infile >outfile
#
# input = Apache/NCSA/.. logfile with IP numbers at start of lines
# output = same logfile with IP addresses resolved to hostnames where
# name lookups succeeded.
#
# this differs from the C based 'logresolve' in that this script
# spawns a number ($CHILDREN) of subprocesses to resolve addresses
# concurrently and sets a short timeout ($TIMEOUT) for each lookup in
# order to keep things moving quickly.
#
# the parent process handles caching of IP->hostnames using a Perl hash
# it also avoids sending the same IP to multiple child processes to be
# resolved multiple times concurrently.
#
# Depending on the settings of $CHILDREN and $TIMEOUT you should see
# significant reductions in the overall time taken to resolve your
# logfiles. With $CHILDREN=40 and $TIMEOUT=5 I've seen 200,000 - 300,000
# logfile lines processed per hour compared to ~45,000 per hour
# with 'logresolve'.
#
# I haven't yet seen any noticable reduction in the percentage of IPs
# that fail to get resolved. Your mileage will no doubt vary. 5s is long
# enough to wait IMO.
#
# Known to work with FreeBSD 2.2
# Known to have problems with Solaris
#
# 980417 - use 'sockaddr_un' for bind/connect to make the script work
# with linux. Fix from Luuk de Boer <luuk_de_boer@pi.net>
require 5.004;
$|=1;
use FileHandle;
use Socket;
use strict;
no strict 'refs';
use vars qw($PROTOCOL);
$PROTOCOL = 0;
my $CHILDREN = 40;
my $TIMEOUT = 5;
my $filename;
my %hash = ();
my $parent = $$;
my @children = ();
for (my $child = 1; $child <=$CHILDREN; $child++) {
my $f = fork();
if (!$f) {
$filename = "./.socket.$parent.$child";
if (-e $filename) { unlink($filename) || warn "$filename .. $!\n";}
&child($child);
exit(0);
}
push(@children, $f);
}
&parent;
&cleanup;
## remove all temporary files before shutting down
sub cleanup {
# die kiddies, die
kill(15, @children);
for (my $child = 1; $child <=$CHILDREN; $child++) {
if (-e "./.socket.$parent.$child") {
unlink("./.socket.$parent.$child")
|| warn ".socket.$parent.$child $!";
}
}
}
sub parent {
# Trap some possible signals to trigger temp file cleanup
$SIG{'KILL'} = $SIG{'INT'} = $SIG{'PIPE'} = \&cleanup;
my %CHILDSOCK;
my $filename;
## fork child processes. Each child will create a socket connection
## to this parent and use an unique temp filename to do so.
for (my $child = 1; $child <=$CHILDREN; $child++) {
$CHILDSOCK{$child}= FileHandle->new;
if (!socket($CHILDSOCK{$child}, AF_UNIX, SOCK_STREAM, $PROTOCOL)) {
warn "parent socket to child failed $!";
}
$filename = "./.socket.$parent.$child";
my $response;
do {
$response = connect($CHILDSOCK{$child}, sockaddr_un($filename));
if ($response != 1) {
sleep(1);
}
} while ($response != 1);
$CHILDSOCK{$child}->autoflush;
}
## All child processes should now be ready or at worst warming up
my (@buffer, $child, $ip, $rest, $hostname, $response);
## read the logfile lines from STDIN
while(<STDIN>) {
@buffer = (); # empty the logfile line buffer array.
$child = 1; # children are numbered 1..N, start with #1
# while we have a child to talk to and data to give it..
do {
push(@buffer, $_); # buffer the line
($ip, $rest) = split(/ /, $_, 2); # separate IP form rest
unless ($hash{$ip}) { # resolve if unseen IP
$CHILDSOCK{$child}->print("$ip\n"); # pass IP to next child
$hash{$ip} = $ip; # don't look it up again.
$child++;
}
} while (($child < ($CHILDREN-1)) and ($_ = <STDIN>));
## now poll each child for a response
while (--$child > 0) {
$response = $CHILDSOCK{$child}->getline;
chomp($response);
# child sends us back both the IP and HOSTNAME, no need for us
# to remember what child received any given IP, and no worries
# what order we talk to the children
($ip, $hostname) = split(/\|/, $response, 2);
$hash{$ip} = $hostname;
}
# resolve all the logfiles lines held in the log buffer array..
for (my $line = 0; $line <=$#buffer; $line++) {
# get next buffered line
($ip, $rest) = split(/ /, $buffer[$line], 2);
# separate IP from rest and replace with cached hostname
printf STDOUT ("%s %s", $hash{$ip}, $rest);
}
}
}
########################################
sub child {
# arg = numeric ID - how the parent refers to me
my $me = shift;
# add trap for alarm signals.
$SIG{'ALRM'} = sub { die "alarmed"; };
# create a socket to communicate with parent
socket(INBOUND, AF_UNIX, SOCK_STREAM, $PROTOCOL)
|| die "Error with Socket: !$\n";
$filename = "./.socket.$parent.$me";
bind(INBOUND, sockaddr_un($filename))
|| die "Error Binding $filename: $!\n";
listen(INBOUND, 5) || die "Error Listening: $!\n";
my ($ip, $send_back);
my $talk = FileHandle->new;
# accept a connection from the parent process. We only ever have
# have one connection where we exchange 1 line of info with the
# parent.. 1 line in (IP address), 1 line out (IP + hostname).
accept($talk, INBOUND) || die "Error Accepting: $!\n";
# disable I/O buffering just in case
$talk->autoflush;
# while the parent keeps sending data, we keep responding..
while(($ip = $talk->getline)) {
chomp($ip);
# resolve the IP if time permits and send back what we found..
$send_back = sprintf("%s|%s", $ip, &nslookup($ip));
$talk->print($send_back."\n");
}
}
# perform a time restricted hostname lookup.
sub nslookup {
# get the IP as an arg
my $ip = shift;
my $hostname = undef;
# do the hostname lookup inside an eval. The eval will use the
# already configured SIGnal handler and drop out of the {} block
# regardless of whether the alarm occured or not.
eval {
alarm($TIMEOUT);
$hostname = gethostbyaddr(gethostbyname($ip), AF_INET);
alarm(0);
};
if ($@ =~ /alarm/) {
# useful for debugging perhaps..
# print "alarming, isn't it? ($ip)";
}
# return the hostname or the IP address itself if there is no hostname
$hostname ne "" ? $hostname : $ip;
}
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