htpdate 6.93 KB
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#!/usr/bin/perl
#
# htpdate time poller version 0.9.3
# Copyright (C) 2005 Eddy Vervest
# Copyright (C) 2010 T(A)ILS dev team <amnesia@boum.org>
#
# 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.
# http://www.gnu.org/copyleft/gpl.html

# Proxy setting are read from environment 
# e.g. in bash for setting environment variables:
#
# export HTTP_PROXY='http://wwwproxy.xs4all.nl:8080'
#
# or set the proxy value here
#
# $ENV{HTTP_PROXY} = 'http://wwwproxy.xs4all.nl:8080';
#
# If proxy authentication is required, specify your userid and password below.

use strict;
use warnings;

use version; our $VERSION = qv('0.9.3');

use Carp;
use Cwd;
use DateTime;
use DateTime::Format::DateParse;
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use English qw( -no_match_vars );
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use Fatal qw( open close );
use File::Temp qw/tempdir/;
use Getopt::Std;
use open qw{:utf8 :std};
use POSIX qw( WIFEXITED );

my $datecommand = '/bin/date';  # "date" command to set time
my $dateparam   = '-s';         # "date" parameter to set time
my $debug       = 0;
my $fullrequest = 0;
my $maxadjust   = 1800;         # maximum time step in seconds
my $minadjust   = 1;            # minimum time step in seconds
my $password    = '';           # password for proxy server
my $quiet       = 0;
my $set_date    = 1;
my $ssl_protocol = 'TLSv1';     # will be passed to wget's --secure-protocol
my $useragent   = "htpdate/$VERSION";
my $userid      = '';           # userid for proxy servers

our ($opt_d, $opt_h, $opt_q, $opt_x, $opt_u, $opt_a, $opt_f);

sub parseCommandLine () {
    # specify valid switches
    getopts('dhqxfu:a:') || usage();

    usage() if $opt_h;
    usage() unless $ARGV[0];

    $> = getpwnam($opt_u)   if $opt_u;
    $useragent = $opt_a     if $opt_a;
    $debug = 1              if $opt_d;
    $fullrequest = 1        if $opt_f;
    $quiet = 1              if $opt_q;
    $set_date = 0           if $opt_x;

    my @urls;
    foreach my $url (@ARGV) {
        unless ( $url =~ /^http/i ) {
            $url = 'https://'.$url;
        }
        push @urls, $url;
    }

    return @urls;
}

sub usage () {

    print STDERR <<USAGE;

htpdate version $VERSION
Usage: $0 [-dhqxf] [-u userid] [-a useragent] <URL> [<URL> ...]

        -d      debug
        -h      show this help
        -q      quiet
        -u      userid to run as
        -x      do not set the time (only show)
        -a      http user agent to use
        -f      request the full page and referenced resources rather than only its header

        e.g. $0 -x http://www.microsoft.com/ https://check.torproject.org/

USAGE

    exit;
}

sub newestDateHeader {
    my ($dir) = @_;

    my $origdir = getcwd;
    chdir $dir;

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    my @files = grep { ! ( $_ =~ m/^\.{1,2}$/ ) } glob('.* *');
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    @files or croak "No downloaded files can be found";

    my $newestdt;

    foreach my $file (@files) {
        next if -l $file || -d _;
        my $date;
        open(my $file_h, '<', $file);
        while (my $line = <$file_h>) {
            chomp $line;
            # empty line == we leave the headers to go into the content
            last if $line eq '';
            last if ($date) = ($line =~ m/^Date:\s+(.*)$/m);
        }
        close $file_h;
        if (defined $date) {
            # RFC 2616 (3.3.1) says Date headers MUST be represented in GMT
            my $dt = DateTime::Format::DateParse->parse_datetime( $date, 'GMT' );
            if (! defined $newestdt || DateTime->compare($dt, $newestdt) > 0) {
                $newestdt = $dt;
            }
        }
    }

    chdir $origdir;
    return $newestdt;
}

sub getRemoteDateDiff {
    my ($url, $fullrequest) = @_;

    defined $url or croak "getRemoteDateDiff must be passed an URL";
    $fullrequest = defined $fullrequest ? $fullrequest : 0;

    my $origdir = getcwd;

    my @wget_options = ( '-U', $useragent, '--quiet', '--no-cache',
                         '-e', 'robots=off', '--save-headers',
                         '--no-directories',
                         '--secure-protocol', $ssl_protocol,
                     );
    if ($fullrequest) {
        push @wget_options, ('--page-requisites', '--span-hosts');
    }
    my @cmdline = ('wget', @wget_options, $url);

    my $tmpdir = tempdir("XXXXXXXXXX", TMPDIR => 1);
    chdir $tmpdir;

    # fetch (the page and) referenced resources:
    # images, stylesheets, scripts, etc.
    WIFEXITED(system(@cmdline)) or croak "Failed to fetch content from $url: $!";
    my $localdt = DateTime->now;
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    my $newestdt;
    eval { $newestdt = newestDateHeader($tmpdir) };
    if ($EVAL_ERROR =~ m/No downloaded files can be found/) {
        croak "No file could be downloaded from $url.";
    }
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    defined $newestdt or croak "Could not get any Date header";

    my $diffdt = $newestdt - $localdt;
    my $diff   = $diffdt->in_units('seconds');
    print "$url => $diff second(s)\n" if $debug;

    chdir $origdir;
    return $diffdt;
}

sub adjustDate {
    my ($diffdt) = @_;

    defined $diffdt or croak "adjustDate was passed an undefined diff";

    my $localdt = DateTime->now;
    my $absdiffdt = $diffdt->is_positive() ? $diffdt : $diffdt->inverse();
    my $diff      = $diffdt->in_units('seconds');

    print "Median diff: $diff second(s)\n" if $debug;

    if ( DateTime::Duration->compare( $absdiffdt,
                                      DateTime::Duration->new(seconds => $maxadjust),
                                      $localdt )
          > 0 ) {
        print STDERR "Not setting clock as diff ($diff seconds) is too large.\n" unless $quiet;
    }
    elsif ( DateTime::Duration->compare($absdiffdt,
                                        DateTime::Duration->new(seconds => $minadjust),
                                        $localdt, )
          <= 0 ) {
        print STDERR "Not setting clock as diff ($diff seconds) is too small.\n" unless $quiet;
    }
    else {
        my $newtimedt = DateTime->now + $diffdt;
        my $newtime = scalar localtime($newtimedt->epoch);
        print "Setting time to $newtime...\n" unless $quiet;
        if ($set_date) {
            $> = 0 if $opt_u;
            open(my $fd, "-|", $datecommand, $dateparam, $newtime);
            if ( $? != 0 ) {
                print STDERR "An error occured setting the time\n";
                while (<$fd>) {
                    print STDERR $_;
                }
            }
            close($fd);
            $> = getpwnam($opt_u) if $opt_u;
        }
    }
}

my @urls = parseCommandLine();
my @diffdts;
foreach my $url (@urls) {
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    my $diffdt;
    eval { $diffdt = getRemoteDateDiff($url, $fullrequest) };
    if ($EVAL_ERROR) {
        print STDERR "$EVAL_ERROR\n";
    }
    else {
        push @diffdts, $diffdt;
    }
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}
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@diffdts or croak "No Date header could be received.";
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my @sorted_diffdts = sort {
    $a->in_units('seconds') <=> $b->in_units('seconds')
} @diffdts;
adjustDate($sorted_diffdts[int(@sorted_diffdts / 2)]);