#!/usr/bin/perl
#
# DownCounter+x: CGI Program for counting downloaded times
#  file: downcntx.cgi
#
#  Copyright (C) 2001 KOMORIYA Takeru
#
# 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 http://www.paken.org:8080/aaf/download/GPL for more details.
#
# Contact to author:
#   KOMORIYA Takeru, AAF Sendai Lab., Japan
#   E-mail: komoriya@paken.org
#      URL: http://www.paken.org:8080/
#
#---------------------------------------------------------------------
# Ver 1.0(12/15,2001): Changed file invoking method.
# Ver 0.9(10/13,2001): Bug fixed for multiple domain.
# Ver 0.1(8/21,2001) : First release
#-------------------------------------------------------------------
# Usage
#  1.Save this file as "/cgi-bin/downcntx.cgi".
#  2.Edit this file and give correct path to perl(at first line),
#    give $password, $serverurl and $local_ip.
#  3.Change permission of this file "chmod 755 downcntx.cgi"
#  4.Create file "touch downcntx.log" and "chmod 666 downcntx.log"
#  5.Create directory "mkdir downcntx_data" and "chmod 777 downcntx_data"
#
#  To invoke DownCounter by link:
#   <A HREF="/cgi-bin/downcntx.cgi?name=PROGRAM_NAME&url=PATH_TO_TARGET_FILE">
#   ex) <A HREF="/cgi-bin/downcntx.cgi?name=foo&url=/programs/foo.tar.gz">
#
#  To show result:
#   access to "/cgi-bin/downcntx.cgi?mode=view"
#-------------------------------------------------------------------

# Password for administration
$password = 'password';

# Server URL
$serverurl ="http://www.yourserver.com";

# Local IP (do not count if accessed from this address)
$local_ip ="192.168.1.2";

# Test mode
$testmode = 0;

# Log file
$logfile = './downcntx.log';

# Path for data directory
$basedir = './downcntx_data/';

# Lock for inhibit multiple invocation
# 0: Don't lock, 1: Lock(symlink), 2: Lock(mkdir)
$lock_key = 1;

# Lock-file
$lockfile = $basedir . ".lock";

#-------------------------------------------------------------------

if ($ENV{'REQUEST_METHOD'} eq "POST") {
    read(STDIN, $buffer, $ENV{'CONTENT_LENGTH'});
} else { $buffer = $ENV{'QUERY_STRING'}; }

@pairs = split(/&/,$buffer);
foreach $pair (@pairs) {

	($name,$value) = split(/=/,$pair);
	$value =~ s/%([a-fA-F0-9][a-fA-F0-9])/pack("C",hex($1))/eg;
	$in{$name} = $value;
}

# Input parameters
$url = $in{'url'};
$nickname = $in{'name'};

# Full-path to log file for given name
$accesslog = $basedir . $nickname;

# View mode
if ($in{'mode'} eq "view"){

    &report;
    exit;
}
# View access-log mode
if ($in{'mode'} eq "accesslog"){
    if ($password eq $in{'passwd'}){
	&report_accesslog;
	exit;
    }
}

# Check wrong file name
if ($nickname =~ /[^\w\.+-]|^$/) { &error('ERROR',"Wrong name: $nickname"); }

# Accessed from Local PC?
if($ENV{'REMOTE_ADDR'} =~ /$local_ip/){
    $fromserverurl=0;
}else{
    $fromserverurl=1;
}

if (($fromserverurl == 1) || ($testmode == 1)){
    # Lock
    &lock if ($lockkey);
    
    # Open and read log-file
    open(IN,"$logfile") || &error("ERROR","Cannot open logfile.");
    @lines = <IN>;
    close(IN);
    
    # Increment matched entry
    $flag=0;
    @new=();
    foreach $line (@lines) {
	($name,$count) = split(/\t/, $line);
	chomp($count);
	if ($nickname eq "$name") {
	    $flag=1;
	    $count++;
	    $newcount=$count;
	    $line = "$name\t$count\n";
	}
	push(@new,$line);
    }

    # Update logfile
    if ($flag == 1) {
	open(OUT,">$logfile") || &error("ERROR","Cannot open logfile.");
	print OUT @new;
	close(OUT);
    }
    # Add to logfile
    elsif ($flag == 0 && $nickname ne "") {
	$newcount=1;
	open(OUT,">>$logfile") || &error("ERROR","Cannot open logfile.");
	print OUT "$nickname\t$newcount\n";
	close(OUT);
    }
    
    # Format Date and Time
    $ENV{'TZ'} = "JST-9";
    ($sec,$min,$hour,$mday,$mon,$year,$wday,$yday,$isdst) = localtime(time);
    $year +=1900;
    $new_date = sprintf("%04d/%02d/%02d", $year , $mon + 1, $mday);
    $new_hour = sprintf("%02d:%02d", $hour,$min);

    # Get remote host
    if($ENV{'REMOTE_HOST'} !~/[a-zA-Z]/){
	$n_host = $ENV{'REMOTE_ADDR'};
	$ENV{'REMOTE_HOST'} = gethostbyaddr(pack('C4',split(/\./,$n_host)),2) || $n_host;
    }

    # Create access log file for given name
    if (!-e $accesslog) {
	if (!open(OUT,"> $accesslog")) { &error('ERROR',"Cannot create: $accesslog"); }
	$newaccesslog = 1;
    }else{
	if (!open(OUT,">> $accesslog")) { &error('ERROR',"Cannot create: $accesslog"); }
    }
    print OUT "$newcount"."\t";
    print OUT "$ENV{'REMOTE_HOST'}"."\t";
    print OUT "$new_date"."\t";
    print OUT "$new_hour"."\n";
    close OUT;
    
    # Change file permission
    if ($newaccesslog == 1) {
	chmod(0666,$accesslog);
    }
    
    # unlock
    &unlock if ($lockkey);
}
if($fromserverurl == 1){
    $url = $serverurl . $url;
}else{
    $url = "http://" . $local_ip . $url;
}

# invoke target file
print <<"EOF";
Content-type: text/html

<HTML><HEAD>
<TITLE>ダウンロード</TITLE>
<META HTTP-EQUIV="Content-type" CONTENT="text/html; charset=Shift_JIS">
</HEAD>
<BODY BGCOLOR="#FFFFFF">
<CENTER>
↓右クリックして保存してください．<P>
<A HREF="$url">$url</A>
</CENTER>
</BODY></HTML>
EOF

exit;

sub lock {
    local($retry)=5;
    # delete old lock (older than 3 minutes)
    if (-e $lockfile) {
	($mtime) = (stat($lockfile))[9];
	if ($mtime && $mtime < time - 180) { &unlock; }
    }
    # symlink lock
    if ($lockkey == 1) {
	while (!symlink(".", $lockfile)) {
	    if (--$retry <= 0) { &error('Server Busy',"Please retry later."); }
	    sleep(1);
	}
    # mkdir lock
    } elsif ($lockkey == 2) {
	while (!mkdir($lockfile, 0755)) {
	    if (--$retry <= 0) { &error('Server Busy',"Please retry later."); }
	    sleep(1);
	}
    }
}
sub unlock {
    if ($lockkey == 1) { unlink($lockfile); }
    elsif ($lockkey == 2) { rmdir($lockfile); }
}

sub error {

	if (-e $lockfile) { unlink($lockfile); }

	print "Content-type: text/html\n\n";
        print "<body>\n";
        print "<h1>$_[0]</h1>\n";
	print "<h3>$_[1]</h3>\n";
        print "</body></html>\n";
        exit;
}

sub report {
    # Lock
    &lock if ($lockkey);
    # Open and read log-file
    open(IN,"$logfile") || &error("ERROR","Cannot open logfile.");
    @lines = <IN>;
    close(IN);
    # Unlock
    &unlock if ($lockkey);

    print "Content-type: text/html\n"."\n";
    print <<"__HEAD__";
<HTML><HEAD><TITLE>Download Count</TITLE></HEAD>
<BODY BGCOLOR="#FFFFFF">
<CENTER>
<H2>Download Statistics</H2>
<TABLE BORDER="1">
<TR>
<TH>Name</TH>
<TH>Count</TH>
</TR>
__HEAD__

    # Print entries
    foreach $line (@lines) {
	($name,$count) = split(/\t/, $line);
	print "<TR>";
	if ($password eq $in{'passwd'}){
	    print "<TD><A HREF='downcntx.cgi?mode=accesslog&name=$name&passwd=$password'>";
	    print "$name</A></TD>";
	}else{
	    print "<TD>$name</TD>";
	}
	print "<TD>$count</TD>";
	print "</TR>\n";
    }

    print <<"__FOOT__";
</TABLE>
<P>
<FORM ACTION="downcntx.cgi" METHOD="post">
<INPUT TYPE="hidden" NAME="mode" VALUE="view">
<INPUT TYPE="password" NAME="passwd" SIZE=8>
<INPUT TYPE="submit" VALUE="admin">
</FORM>
</CENTER>
</BODY></HTML>
__FOOT__
}

sub report_accesslog {
    # Lock
    &lock if ($lockkey);
    # Open and read log-file
    open(IN,"$accesslog") || &error("ERROR","Cannot open access-log file.");
    @lines = <IN>;
    close(IN);
    # Unlock
    &unlock if ($lockkey);

    print "Content-type: text/html\n"."\n";
    print <<"__HEAD__";
<HTML><HEAD><TITLE>Download Log of $nickname</TITLE></HEAD>
<BODY BGCOLOR="#FFFFFF">
<CENTER>
<H2>Download Log of $nickname</H2>
<TABLE BORDER="1">
<TR>
<TH>Count</TH>
<TH>Host</TH>
<TH>Date</TH>
<TH>Time</TH>
</TR>
__HEAD__

    # Print entries
    foreach $line (@lines) {
	($count,$host,$date,$time) = split(/\t/, $line);
	print "<TR>";
	print "<TD>$count</TD>";
	print "<TD>$host</TD>";
	print "<TD>$date</TD>";
	print "<TD>$time</TD>";
	print "</TR>\n";
    }

    print <<"__FOOT__";
</TABLE>
</CENTER>
</BODY></HTML>
__FOOT__
}