#!/usr/bin/perl -w
# sanada2.pl - Don Yang (uguu.org)
#
# 11/26/03


use strict;
use Socket;

local (*SERVER, *CLIENT, *FILE);
my ($Name, $Port, $Type, $Size, $HEADER, $EOL);
my ($rin, $rout, $i, $j);

sub Text
{
   print "$$: ", (scalar(localtime)), ": @_\n";
}

die "$0 <file> [port] [type]\n" unless( $#ARGV > -1 );
($Name, $Port, $Type) = @ARGV;
die "$Name is empty\n" unless( (-f $Name) && ($Size = -s $Name) > 0 );
$Port ||= 80;
$Type ||= "application/octet-stream";
$EOL = "\r\n";
$HEADER =
   "Server: Sanada-san$EOL" .
   "Accept-Ranges: bytes$EOL" .
   "Content-Type: $Type$EOL" .
   "Connection: close$EOL$EOL";

$SIG{"CHLD"} = "IGNORE";
die "$!\n" unless(
   socket(SERVER, PF_INET, SOCK_STREAM, getprotobyname("tcp")) &&
   bind(SERVER, sockaddr_in($Port, INADDR_ANY)) &&
   listen(SERVER, 5) &&
   binmode(SERVER));
$rin = "";
vec($rin, fileno(SERVER), 1) = 1;
Text("serving $Name (type=$Type, size=$Size)");
Text("listening on port $Port");
while( select($rout = $rin, undef, undef, undef) )
{
   if( vec($rout, fileno(SERVER), 1) )
   {
      $j = accept(CLIENT, SERVER);
      ($j, $i) = sockaddr_in($j);
      $i = inet_ntoa($i);
      if( fork )
      {
         close(CLIENT);
      }
      else
      {
         Text("request from $i:$j");

         binmode(CLIENT);
         defined(recv(CLIENT, $rin, 1024, 0)) || die $!;

         $i = 0;
         $j = $Size - 1;
         if( $rin =~ /\s+user-agent:\s*([^\r\n]+)/i )
         {
            Text("agent=$1");
         }
         if( $rin =~ /\s+referer:\s*([^\r\n]+)/i )
         {
            Text("referer=$1");
         }
         if( $rin =~ /\s+range:\s*bytes=(\d+)-(\d+)/i )
         {
            $i = $1;
            $j = $2;
         }
         elsif( $rin =~ /\s+range:\s*bytes=(\d+)-/i )
         {
            $i = $1;
         }
         elsif( $rin =~ /\s+range:\s*bytes=-(\d+)/i )
         {
            $i = $Size - $1;
         }

         # Header
         if( $i >= $Size || $j >= $Size || $j < $i )
         {
            $rout =
               "HTTP/1.1 416 Requested Range Not Satisfiable$EOL" .
               "Content-Range: bytes */$Size$EOL";
            $Type = 0;
         }
         else
         {
            if( $i > 0 || $j < $Size - 1 )
            {
               $rout =
                  "HTTP/1.1 206 Partial Content$EOL" .
                  "Content-Range: bytes $i-$j/$Size$EOL";
            }
            else
            {
               $rout = "HTTP/1.1 200 OK$EOL";
            }
            $rout .= "Content-Length: " . ($j - $i + 1) . $EOL;
            $Type = 1;
         }
         $rout .= $HEADER;

         send(CLIENT, $rout, 0) || die $!;
         if( $Type && ($rin =~ /^GET /) )
         {
            $Type = 0;
            open(FILE, "< $Name");
            $j++;
            for(seek(FILE, $i, 0); $i < $j; $i += $Port)
            {
               if( ($Port = $j - $i) > 0x4000 )
               {
                  $Port = 0x4000;
               }
               read(FILE, $rout, $Port);
               last unless defined(send(CLIENT, $rout, 0));
               $Type += $Port;
            }
            close(FILE);
            $Type = "~" . $Type if( $i < $j );
            Text("sent $Type bytes");
         }
         shutdown(CLIENT, 2);
         close(CLIENT);
         exit(0);
      }
   }
}
die "$!\n";