curl/tests/ftpserver.pl

#!/usr/bin/env perl
#***************************************************************************
#                                  _   _ ____  _
#  Project                     ___| | | |  _ \| |
#                             / __| | | | |_) | |
#                            | (__| |_| |  _ <| |___
#                             \___|\___/|_| \_\_____|
#
# Copyright (C) 1998 - 2009, Daniel Stenberg, <daniel@haxx.se>, et al.
#
# This software is licensed as described in the file COPYING, which
# you should have received as part of this distribution. The terms
# are also available at http://curl.haxx.se/docs/copyright.html.
#
# You may opt to use, copy, modify, merge, publish, distribute and/or sell
# copies of the Software, and permit persons to whom the Software is
# furnished to do so, under the terms of the COPYING file.
#
# This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
# KIND, either express or implied.
#
# $Id$
###########################################################################

# This is a server designed for the curl test suite.
#
# In December 2009 we started remaking the server to support more protocols
# that are similar in spirit. Like POP3, IMAP and SMTP in addition to the
# FTP it already supported since a long time.
#
# It is meant to exercise curl, it is not meant to be a fully working
# or even very standard compliant server.
#
# You may optionally specify port on the command line, otherwise it'll
# default to port 8921.
#
# All socket/network/TCP related stuff is done by the 'sockfilt' program.
#

use strict;
use IPC::Open2;

require "getpart.pm";
require "ftp.pm";

#BEGIN {
#    if($] > 5.006) {
#        use Time::HiRes qw( gettimeofday );
#    }
#}

my $ftpdnum="";

my $logfilename = 'log/logfile.log'; # Override this for each test server

#######################################################################
# getlogfilename returns a log file name depending on given arguments.
#
sub getlogfilename {
    my ($proto, $ipversion, $ssl, $instance, $sockfilter) = @_;
    my $filename;

    # For now, simply mimic old behavior.
    $filename = "log/ftpd$ftpdnum.log";

    return $filename;
}

#######################################################################
# logmsg is general message logging subroutine for our test servers.
#
sub logmsg {
    my $now;
#   if($] > 5.006) {
#       my ($seconds, $usec) = gettimeofday();
#       my ($sec,$min,$hour,$mday,$mon,$year,$wday,$yday,$isdst) =
#           localtime($seconds);
#       $now = sprintf("%02d:%02d:%02d.%06d ", $hour, $min, $sec, $usec);
#   }
#   else {
        my $seconds = time();
        my ($sec,$min,$hour,$mday,$mon,$year,$wday,$yday,$isdst) =
            localtime($seconds);
        $now = sprintf("%02d:%02d:%02d ", $hour, $min, $sec);
#   }
    if(open(LOGFILEFH, ">>$logfilename")) {
        print LOGFILEFH $now;
        print LOGFILEFH @_;
        close(LOGFILEFH);
    }
}

sub ftpmsg {
  # append to the server.input file
  open(INPUT, ">>log/server$ftpdnum.input") ||
    logmsg "failed to open log/server$ftpdnum.input\n";

  print INPUT @_;
  close(INPUT);

  # use this, open->print->close system only to make the file
  # open as little as possible, to make the test suite run
  # better on windows/cygwin
}

my $verbose=0; # set to 1 for debugging
my $pasvbadip=0;
my $retrweirdo=0;
my $retrnosize=0;
my $srcdir=".";
my $nosave=0;
my $controldelay=0; # set to 1 to delay the control connect data sending to
 # test that curl deals with that nicely
my $slavepid; # for the DATA connection sockfilt slave process
my $ipv6;
my $ext; # append to log/pid file names
my $grok_eprt;
my $port = 8921; # just a default
my $listenaddr = "127.0.0.1"; # just a default
my $pidfile = ".ftpd.pid"; # a default, use --pidfile

my $SERVERLOGS_LOCK="log/serverlogs.lock"; # server logs advisor read lock
my $serverlogslocked=0;

my $proto="ftp";

do {
    if($ARGV[0] eq "-v") {
        $verbose=1;
    }
    elsif($ARGV[0] eq "-s") {
        $srcdir=$ARGV[1];
        shift @ARGV;
    }
    elsif($ARGV[0] eq "--id") {
        $ftpdnum=$ARGV[1];
        shift @ARGV;
    }
    elsif($ARGV[0] eq "--proto") {
        # ftp pop3 imap smtp
        $proto=$ARGV[1];
        shift @ARGV;
    }
    elsif($ARGV[0] eq "--pidfile") {
        $pidfile=$ARGV[1];
        shift @ARGV;
    }
    elsif($ARGV[0] eq "--ipv6") {
        $ipv6="--ipv6";
        $ext="ipv6";
        $grok_eprt = 1;
    }
    elsif($ARGV[0] eq "--port") {
        $port = $ARGV[1];
        shift @ARGV;
    }
    elsif($ARGV[0] eq "--addr") {
        $listenaddr = $ARGV[1];
        $listenaddr =~ s/^\[(.*)\]$/$1/;
        shift @ARGV;
    }
} while(shift @ARGV);

# a dedicated protocol has been selected, check that it's a fine one
if($proto !~ /^(ftp|imap|pop3|smtp)\z/) {
    die "unsupported protocol selected";
}

sub catch_zap {
    my $signame = shift;
    ftpkillslaves($verbose);
    unlink($pidfile);
    if($serverlogslocked) {
        $serverlogslocked = 0;
        clear_advisor_read_lock($SERVERLOGS_LOCK);
    }
    exit;
}
$SIG{INT} = \&catch_zap;
$SIG{TERM} = \&catch_zap;

my $sfpid;

local(*SFREAD, *SFWRITE);

sub sysread_or_die {
    my $FH     = shift;
    my $scalar = shift;
    my $length = shift;
    my $fcaller;
    my $lcaller;
    my $result;

    $result = sysread($$FH, $$scalar, $length);

    if(not defined $result) {
        ($fcaller, $lcaller) = (caller)[1,2];
        logmsg "Failed to read input\n";
        logmsg "Error: ftp$ftpdnum$ext sysread error: $!\n";
        killpid($verbose, $sfpid);
        logmsg "Exited from sysread_or_die() at $fcaller " .
               "line $lcaller. ftp$ftpdnum$ext sysread error: $!\n";
        unlink($pidfile);
        if($serverlogslocked) {
            $serverlogslocked = 0;
            clear_advisor_read_lock($SERVERLOGS_LOCK);
        }
        exit;
    }
    elsif($result == 0) {
        ($fcaller, $lcaller) = (caller)[1,2];
        logmsg "Failed to read input\n";
        logmsg "Error: ftp$ftpdnum$ext read zero\n";
        killpid($verbose, $sfpid);
        logmsg "Exited from sysread_or_die() at $fcaller " .
               "line $lcaller. ftp$ftpdnum$ext read zero\n";
        unlink($pidfile);
        if($serverlogslocked) {
            $serverlogslocked = 0;
            clear_advisor_read_lock($SERVERLOGS_LOCK);
        }
        exit;
    }

    return $result;
}

sub startsf {
    my $cmd="./server/sockfilt --port $port --logfile log/sockctrl$ftpdnum$ext.log --pidfile .sockfilt$ftpdnum$ext.pid $ipv6";
    $sfpid = open2(*SFREAD, *SFWRITE, $cmd);

    print STDERR "$cmd\n" if($verbose);

    print SFWRITE "PING\n";
    my $pong;
    sysread SFREAD, $pong, 5;

    if($pong !~ /^PONG/) {
        logmsg "Failed sockfilt command: $cmd\n";
        killpid($verbose, $sfpid);
        unlink($pidfile);
        if($serverlogslocked) {
            $serverlogslocked = 0;
            clear_advisor_read_lock($SERVERLOGS_LOCK);
        }
        die "Failed to start sockfilt!";
    }
}

$logfilename = getlogfilename();

startsf();

logmsg sprintf("%s server listens on port IPv%d/$port\n", uc($proto),
               $ipv6?6:4);
open(PID, ">$pidfile");
print PID $$."\n";
close(PID);

logmsg("logged pid $$ in $pidfile\n");

sub sockfilt {
    my $l;
    foreach $l (@_) {
        printf SFWRITE "DATA\n%04x\n", length($l);
        print SFWRITE $l;
    }
}


sub sockfiltsecondary {
    my $l;
    foreach $l (@_) {
        printf DWRITE "DATA\n%04x\n", length($l);
        print DWRITE $l;
    }
}


# Send data to the client on the control stream, which happens to be plain
# stdout.

sub sendcontrol {
    if(!$controldelay) {
        # spit it all out at once
        sockfilt @_;
    }
    else {
        my $a = join("", @_);
        my @a = split("", $a);

        for(@a) {
            sockfilt $_;
            select(undef, undef, undef, 0.01);
        }
    }
    my $log;
    foreach $log (@_) {
        my $l = $log;
        $l =~ s/[\r\n]//g;
        logmsg "> \"$l\"\n";
    }
}

# Send data to the client on the data stream

sub senddata {
    my $l;
    foreach $l (@_) {
      if(!$controldelay) {
        # spit it all out at once
        sockfiltsecondary $l;
      }
      else {
          # pause between each byte
          for (split(//,$l)) {
              sockfiltsecondary $_;
              select(undef, undef, undef, 0.01);
          }
      }
    }
}

my %displaytext;
my %commandfunc;

# callback functions for certain commands
# and text shown before the function specified below is run

if($proto eq "ftp") {
    %displaytext = ('USER' => '331 We are happy you popped in!',
                    'PASS' => '230 Welcome you silly person',
                    'PORT' => '200 You said PORT - I say FINE',
                    'TYPE' => '200 I modify TYPE as you wanted',
                    'LIST' => '150 here comes a directory',
                    'NLST' => '150 here comes a directory',
                    'CWD'  => '250 CWD command successful.',
                    'SYST' => '215 UNIX Type: L8', # just fake something
                    'QUIT' => '221 bye bye baby', # just reply something
                    'PWD'  => '257 "/nowhere/anywhere" is current directory',
                    'MKD'  => '257 Created your requested directory',
                    'REST' => '350 Yeah yeah we set it there for you',
                    'DELE' => '200 OK OK OK whatever you say',
                    'RNFR' => '350 Received your order. Please provide more',
                    'RNTO' => '250 Ok, thanks. File renaming completed.',
                    'NOOP' => '200 Yes, I\'m very good at doing nothing.',
                    'PBSZ' => '500 PBSZ not implemented',
                    'PROT' => '500 PROT not implemented',
        );

    %commandfunc = ( 'PORT' => \&PORT_ftp,
                     'EPRT' => \&PORT_ftp,
                     'LIST' => \&LIST_ftp,
                     'NLST' => \&NLST_ftp,
                     'PASV' => \&PASV_ftp,
                     'EPSV' => \&PASV_ftp,
                     'RETR' => \&RETR_ftp,   
                     'SIZE' => \&SIZE_ftp,
                     'REST' => \&REST_ftp,
                     'STOR' => \&STOR_ftp,
                     'APPE' => \&STOR_ftp, # append looks like upload
                     'MDTM' => \&MDTM_ftp,
        );
}
elsif($proto eq "pop3") {
    %commandfunc = ('RETR' => \&RETR_pop3,
        );

    %displaytext = ('USER' => '+OK We are happy you popped in!',
                    'PASS' => '+OK Access granted',
                    'QUIT' => '+OK byebye',
        );

}
elsif($proto eq "imap") {
    %commandfunc = ('FETCH' => \&FETCH_imap,
                    'SELECT' => \&SELECT_imap,
        );

    %displaytext = ('LOGIN' => ' OK We are happy you popped in!',
                    'SELECT' => ' OK selection done',
                    'LOGOUT' => ' OK thanks for the fish',
        );

}


sub close_dataconn {
    my ($closed)=@_; # non-zero if already disconnected

    if(!$closed) {
        logmsg "* disconnect data connection\n";
        print DWRITE "DISC\n";
        my $i;
        sysread DREAD, $i, 5;
    }
    else {
        logmsg "data connection already disconnected\n";
    }
    logmsg "=====> Closed data connection\n";

    logmsg "* quit sockfilt for data (pid $slavepid)\n";
    print DWRITE "QUIT\n";
    waitpid $slavepid, 0;
    $slavepid=0;
}

################
################ IMAP commands 
################

# global to allow the command functions to read it
my $cmdid;

# what was picked by SELECT
my $selected;

sub SELECT_imap {
    my ($testno) = @_;
    my @data;
    my $size;

    logmsg "SELECT_imap got test $testno\n";

    $selected = $testno;

    return 0;
}


sub FETCH_imap {
     my ($testno) = @_;
     my @data;
     my $size;

     logmsg "FETCH_imap got test $testno\n";

     $testno = $selected;

     if($testno =~ /^verifiedserver$/) {
         # this is the secret command that verifies that this actually is
         # the curl test server
         my $response = "WE ROOLZ: $$\r\n";
         if($verbose) {
             print STDERR "FTPD: We returned proof we are the test server\n";
         }
         $data[0] = $response;
         logmsg "return proof we are we\n";
     }
     else {
         logmsg "retrieve a mail\n";

         $testno =~ s/^([^0-9]*)//;
         my $testpart = "";
         if ($testno > 10000) {
             $testpart = $testno % 10000;
             $testno = int($testno / 10000);
         }

         # send mail content
         loadtest("$srcdir/data/test$testno");

         @data = getpart("reply", "data$testpart");
     }

     for (@data) {
         $size += length($_);
     }

     sendcontrol "* FETCH starts {$size}\r\n";

     for my $d (@data) {
         sendcontrol $d;
     }

     sendcontrol "$cmdid OK FETCH completed\r\n";
    
     return 0;
}

################
################ POP3 commands 
################

sub RETR_pop3 {
     my ($testno) = @_;
     my @data;

     if($testno =~ /^verifiedserver$/) {
         # this is the secret command that verifies that this actually is
         # the curl test server
         my $response = "WE ROOLZ: $$\r\n";
         if($verbose) {
             print STDERR "FTPD: We returned proof we are the test server\n";
         }
         $data[0] = $response;
         logmsg "return proof we are we\n";
     }
     else {
         logmsg "retrieve a mail\n";

         $testno =~ s/^([^0-9]*)//;
         my $testpart = "";
         if ($testno > 10000) {
             $testpart = $testno % 10000;
             $testno = int($testno / 10000);
         }

         # send mail content
         loadtest("$srcdir/data/test$testno");

         @data = getpart("reply", "data$testpart");
     }

     sendcontrol "+OK Mail transfer starts\r\n";

     for my $d (@data) {
         sendcontrol $d;
     }

     # end with the magic 5-byte end of mail marker
     sendcontrol "\r\n.\r\n";
    
     return 0;
}

################
################ FTP commands 
################
my $rest=0;
sub REST_ftp {
    $rest = $_[0];
    logmsg "Set REST position to $rest\n"
}

sub LIST_ftp {
  #  print "150 ASCII data connection for /bin/ls (193.15.23.1,59196) (0 bytes)\r\n";

# this is a built-in fake-dir ;-)
my @ftpdir=("total 20\r\n",
"drwxr-xr-x   8 98       98           512 Oct 22 13:06 .\r\n",
"drwxr-xr-x   8 98       98           512 Oct 22 13:06 ..\r\n",
"drwxr-xr-x   2 98       98           512 May  2  1996 .NeXT\r\n",
"-r--r--r--   1 0        1             35 Jul 16  1996 README\r\n",
"lrwxrwxrwx   1 0        1              7 Dec  9  1999 bin -> usr/bin\r\n",
"dr-xr-xr-x   2 0        1            512 Oct  1  1997 dev\r\n",
"drwxrwxrwx   2 98       98           512 May 29 16:04 download.html\r\n",
"dr-xr-xr-x   2 0        1            512 Nov 30  1995 etc\r\n",
"drwxrwxrwx   2 98       1            512 Oct 30 14:33 pub\r\n",
"dr-xr-xr-x   5 0        1            512 Oct  1  1997 usr\r\n");

    logmsg "pass LIST data on data connection\n";
    for(@ftpdir) {
        senddata $_;
    }
    close_dataconn(0);
    sendcontrol "226 ASCII transfer complete\r\n";
    return 0;
}

sub NLST_ftp {
    my @ftpdir=("file", "with space", "fake", "..", " ..", "funny", "README");
    logmsg "pass NLST data on data connection\n";
    for(@ftpdir) {
        senddata "$_\r\n";
    }
    close_dataconn(0);
    sendcontrol "226 ASCII transfer complete\r\n";
    return 0;
}

sub MDTM_ftp {
    my $testno = $_[0];
    my $testpart = "";
    if ($testno > 10000) {
        $testpart = $testno % 10000;
        $testno = int($testno / 10000);
    }

    loadtest("$srcdir/data/test$testno");

    my @data = getpart("reply", "mdtm");

    my $reply = $data[0];
    chomp $reply;

    if($reply <0) {
        sendcontrol "550 $testno: no such file.\r\n";
    }
    elsif($reply) {
        sendcontrol "$reply\r\n";
    }
    else {
        sendcontrol "500 MDTM: no such command.\r\n";
    }
    return 0;
}

sub SIZE_ftp {
    my $testno = $_[0];
    my $testpart = "";
    if ($testno > 10000) {
        $testpart = $testno % 10000;
        $testno = int($testno / 10000);
    }

    loadtest("$srcdir/data/test$testno");

    if($testno eq "verifiedserver") {
        my $response = "WE ROOLZ: $$\r\n";
        my $size = length($response);
        sendcontrol "213 $size\r\n";
        return 0;
    }

    my @data = getpart("reply", "size");

    my $size = $data[0];

    if($size) {
        if($size > -1) {
            sendcontrol "213 $size\r\n";
        }
        else {
            sendcontrol "550 $testno: No such file or directory.\r\n";
        }
    }
    else {
        $size=0;
        @data = getpart("reply", "data$testpart");
        for(@data) {
            $size += length($_);
        }
        if($size) {
            sendcontrol "213 $size\r\n";
        }
        else {
            sendcontrol "550 $testno: No such file or directory.\r\n";
        }
    }
    return 0;
}

sub RETR_ftp {
    my ($testno) = @_;

    if($testno =~ /^verifiedserver$/) {
        # this is the secret command that verifies that this actually is
        # the curl test server
        my $response = "WE ROOLZ: $$\r\n";
        my $len = length($response);
        sendcontrol "150 Binary junk ($len bytes).\r\n";
        senddata "WE ROOLZ: $$\r\n";
        close_dataconn(0);
        sendcontrol "226 File transfer complete\r\n";
        if($verbose) {
            print STDERR "FTPD: We returned proof we are the test server\n";
        }
        return 0;
    }

    $testno =~ s/^([^0-9]*)//;
    my $testpart = "";
    if ($testno > 10000) {
        $testpart = $testno % 10000;
        $testno = int($testno / 10000);
    }

    loadtest("$srcdir/data/test$testno");

    my @data = getpart("reply", "data$testpart");

    my $size=0;
    for(@data) {
        $size += length($_);
    }

    my %hash = getpartattr("reply", "data$testpart");

    if($size || $hash{'sendzero'}) {
    
        if($rest) {
            # move read pointer forward
            $size -= $rest;
            logmsg "REST $rest was removed from size, makes $size left\n";
            $rest = 0; # reset REST offset again
        }
        if($retrweirdo) {
            sendcontrol "150 Binary data connection for $testno () ($size bytes).\r\n",
            "226 File transfer complete\r\n";

            for(@data) {
                my $send = $_;
                senddata $send;
            }
            close_dataconn(0);
            $retrweirdo=0; # switch off the weirdo again!
        }
        else {
            my $sz = "($size bytes)";
            if($retrnosize) {
                $sz = "size?";
            }

            sendcontrol "150 Binary data connection for $testno () $sz.\r\n";

            for(@data) {
                my $send = $_;
                senddata $send;
            }
            close_dataconn(0);
            sendcontrol "226 File transfer complete\r\n";
        }
    }
    else {
        sendcontrol "550 $testno: No such file or directory.\r\n";
    }
    return 0;
}

sub STOR_ftp {
    my $testno=$_[0];

    my $filename = "log/upload.$testno";

    logmsg "STOR test number $testno in $filename\n";

    sendcontrol "125 Gimme gimme gimme!\r\n";

    open(FILE, ">$filename") ||
        return 0; # failed to open output

    my $line;
    my $ulsize=0;
    my $disc=0;
    while (5 == (sysread DREAD, $line, 5)) {
        if($line eq "DATA\n") {
            my $i;
            sysread DREAD, $i, 5;

            #print STDERR "  GOT: $i";

            my $size = hex($i);
            sysread DREAD, $line, $size;
            
            #print STDERR "  GOT: $size bytes\n";

            $ulsize += $size;
            print FILE $line if(!$nosave);
            logmsg "> Appending $size bytes to file\n";
        }
        elsif($line eq "DISC\n") {
            # disconnect!
            $disc=1;
            last;
        }
        else {
            logmsg "No support for: $line";
            last;
        }
    }
    if($nosave) {
        print FILE "$ulsize bytes would've been stored here\n";
    }
    close(FILE);
    close_dataconn($disc);
    logmsg "received $ulsize bytes upload\n";
    sendcontrol "226 File transfer complete\r\n";
    return 0;
}

sub PASV_ftp {
    my ($arg, $cmd)=@_;
    my $pasvport;
    my $pidf=".sockdata$ftpdnum$ext.pid";

    my $prev = processexists($pidf);
    if($prev > 0) {
        print "kill existing server: $prev\n" if($verbose);
        killpid($verbose, $prev);
    }

    # We fire up a new sockfilt to do the data transfer for us.
    $slavepid = open2(\*DREAD, \*DWRITE,
                      "./server/sockfilt --port 0 --logfile log/sockdata$ftpdnum$ext.log --pidfile $pidf $ipv6");

    print DWRITE "PING\n";
    my $pong;

    sysread_or_die(\*DREAD, \$pong, 5);

    if($pong !~ /^PONG/) {
        killpid($verbose, $slavepid);
        sendcontrol "500 no free ports!\r\n";
        logmsg "failed to run sockfilt for data connection\n";
        return 0;
    }

    logmsg "Run sockfilt for data on pid $slavepid\n";

    # Find out what port we listen on
    my $i;
    print DWRITE "PORT\n";
        
    # READ the response code
    sysread_or_die(\*DREAD, \$i, 5);

    # READ the response size
    sysread_or_die(\*DREAD, \$i, 5);

    my $size = hex($i);
        
    # READ the response data
    sysread_or_die(\*DREAD, \$i, $size);
        
    # The data is in the format
    # IPvX/NNN

    if($i =~ /IPv(\d)\/(\d+)/) {
        # FIX: deal with IP protocol version
        $pasvport = $2;
    }

    if($cmd ne "EPSV") {
        # PASV reply
        my $p=$listenaddr;
        $p =~ s/\./,/g;
        if($pasvbadip) {
            $p="1,2,3,4";
        }
        sendcontrol sprintf("227 Entering Passive Mode ($p,%d,%d)\n",
                            ($pasvport/256), ($pasvport%256));
    }
    else {
        # EPSV reply
        sendcontrol sprintf("229 Entering Passive Mode (|||%d|)\n", $pasvport);
    }

    eval {
        local $SIG{ALRM} = sub { die "alarm\n" };

        # assume swift operations unless explicitly slow
        alarm ($controldelay?20:10);

        # Wait for 'CNCT'
        my $input;

        while(sysread(DREAD, $input, 5)) {

            if($input !~ /^CNCT/) {
                # we wait for a connected client
                logmsg "Odd, we got $input from client\n";
                next;
            }
            logmsg "====> Client DATA connect\n";
            last;
        }
        alarm 0;
    };
    if ($@) {
        # timed out

        print DWRITE "QUIT\n";
        waitpid $slavepid, 0;
        logmsg "accept failed\n";
        $slavepid=0;
        return;
    }
    else {
        logmsg "data connection setup on port $pasvport\n";
    }

    return;
}

# Support both PORT and EPRT here. Consider LPRT too.

sub PORT_ftp {
    my ($arg, $cmd) = @_;
    my $port;
    my $addr;

    # We always ignore the given IP and use localhost.

    if($cmd eq "PORT") {
        if($arg !~ /(\d+),(\d+),(\d+),(\d+),(\d+),(\d+)/) {
            logmsg "bad PORT-line: $arg\n";
            sendcontrol "500 silly you, go away\r\n";
            return 0;
        }
        $port = ($5<<8)+$6;
        $addr = "$1.$2.$3.$4";
    }
    # EPRT |2|::1|49706|
    elsif(($cmd eq "EPRT") && ($grok_eprt)) {
        if($arg !~ /(\d+)\|([^\|]+)\|(\d+)/) {
            sendcontrol "500 silly you, go away\r\n";
            return 0;
        }
        sendcontrol "200 Thanks for dropping by. We contact you later\r\n";
        $port = $3;
        $addr = $2;
    }
    else {
        sendcontrol "500 we don't like $cmd now\r\n";
        return 0;
    }

    if(!$port || $port > 65535) {
        print STDERR "very illegal PORT number: $port\n";
        return 1;
    }

    # We fire up a new sockfilt to do the data transfer for us.
    # FIX: make it use IPv6 if need be
    my $filtcmd="./server/sockfilt --connect $port --addr $addr --logfile log/sockdata$ftpdnum$ext.log --pidfile .sockdata$ftpdnum$ext.pid $ipv6";
    $slavepid = open2(\*DREAD, \*DWRITE, $filtcmd);

    print STDERR "$filtcmd\n" if($verbose);

    print DWRITE "PING\n";
    my $pong;
    sysread DREAD, $pong, 5;

    if($pong !~ /^PONG/) {
        logmsg "Failed sockfilt for data connection\n";
        killpid($verbose, $slavepid);
    }

    logmsg "====> Client DATA connect to port $port\n";

    return;
}

my %customreply;
my %customcount;
my %delayreply;
sub customize {
    $nosave = 0; # default is to save as normal
    $controldelay = 0; # default is no delaying the responses
    $retrweirdo = 0;
    $retrnosize = 0;
    $pasvbadip = 0;
    $nosave = 0;
    %customreply = ();
    %customcount = ();
    %delayreply = ();

    open(CUSTOM, "<log/ftpserver.cmd") ||
        return 1;

    logmsg "FTPD: Getting commands from log/ftpserver.cmd\n";

    while(<CUSTOM>) {
        if($_ =~ /REPLY ([A-Z]+) (.*)/) {
            $customreply{$1}=eval "qq{$2}";
            logmsg "FTPD: set custom reply for $1\n";
        }
        if($_ =~ /COUNT ([A-Z]+) (.*)/) {
            # we blank the customreply for this command when having
            # been used this number of times
            $customcount{$1}=$2;
            logmsg "FTPD: blank custom reply for $1 after $2 uses\n";
        }
        elsif($_ =~ /DELAY ([A-Z]+) (\d*)/) {
            $delayreply{$1}=$2;
            logmsg "FTPD: delay reply for $1 with $2 seconds\n";
        }
        elsif($_ =~ /SLOWDOWN/) {
            $controldelay=1;
            logmsg "FTPD: send response with 0.1 sec delay between each byte\n";
        }
        elsif($_ =~ /RETRWEIRDO/) {
            logmsg "FTPD: instructed to use RETRWEIRDO\n";
            $retrweirdo=1;
        }
        elsif($_ =~ /RETRNOSIZE/) {
            logmsg "FTPD: instructed to use RETRNOSIZE\n";
            $retrnosize=1;
        }
        elsif($_ =~ /PASVBADIP/) {
            logmsg "FTPD: instructed to use PASVBADIP\n";
            $pasvbadip=1;
        }
        elsif($_ =~ /NOSAVE/) {
            # don't actually store the file we upload - to be used when
            # uploading insanely huge amounts
            $nosave = 1;
            logmsg "FTPD: NOSAVE prevents saving of uploaded data\n";
        }
    }
    close(CUSTOM);
}

my @welcome;

if($proto eq "ftp") {
    @welcome=(
        '220-        _   _ ____  _     '."\r\n",
        '220-    ___| | | |  _ \| |    '."\r\n",
        '220-   / __| | | | |_) | |    '."\r\n",
        '220-  | (__| |_| |  _ <| |___ '."\r\n",
        '220    \___|\___/|_| \_\_____|'."\r\n");
}
elsif($proto eq "pop3") {
    @welcome=(
        '        _   _ ____  _     '."\r\n",
        '    ___| | | |  _ \| |    '."\r\n",
        '   / __| | | | |_) | |    '."\r\n",
        '  | (__| |_| |  _ <| |___ '."\r\n",
        '   \___|\___/|_| \_\_____|'."\r\n",
        '+OK cURL POP3 server ready to serve'."\r\n");
}
elsif($proto eq "imap") {
    @welcome=(
        '        _   _ ____  _     '."\r\n",
        '    ___| | | |  _ \| |    '."\r\n",
        '   / __| | | | |_) | |    '."\r\n",
        '  | (__| |_| |  _ <| |___ '."\r\n",
        '   \___|\___/|_| \_\_____|'."\r\n",
        '* OK cURL IMAP server ready to serve'."\r\n");
}


while(1) {
    #
    # We read 'sockfilt' commands.
    # 
    my $input;

    logmsg "Awaiting input\n";
    sysread_or_die(\*SFREAD, \$input, 5);

    if($input !~ /^CNCT/) {
        # we wait for a connected client
        logmsg "sockfilt said: $input";
        next;
    }
    logmsg "====> Client connect\n";

    set_advisor_read_lock($SERVERLOGS_LOCK);
    $serverlogslocked = 1;

    # flush data:
    $| = 1;

    killpid($verbose, $slavepid);
    $slavepid=0;
        
    &customize(); # read test control instructions

    sendcontrol @welcome;
    if($verbose) {
        for(@welcome) {
            print STDERR "OUT: $_";
        }
    }

    while(1) {
        my $i;

        # Now we expect to read DATA\n[hex size]\n[prot], where the [prot]
        # part only is FTP lingo.

        # COMMAND
        sysread_or_die(\*SFREAD, \$i, 5);

        if($i !~ /^DATA/) {
            logmsg "sockfilt said $i";
            if($i =~ /^DISC/) {
                # disconnect
                last;
            }
            next;
        }

        # SIZE of data
        sysread_or_die(\*SFREAD, \$i, 5);

        my $size = hex($i);

        # data
        sysread SFREAD, $_, $size;
        
        ftpmsg $_;
        
        # Remove trailing CRLF.
        s/[\n\r]+$//;

        my $FTPCMD;
        my $FTPARG;
        my $full=$_;
        if($proto eq "imap") {
            # IMAP is different with its identifier first on the command line
            unless (m/^([^ ]+) ([^ ]+) (.*)/ ||
                    m/^([^ ]+) ([^ ]+)/) {
                sendcontrol "$1 '$_': command not understood.\r\n";
                last;
            }
            $cmdid=$1; # set the global variable
            $FTPCMD=$2;
            $FTPARG=$3;
        }
        else {
            unless (m/^([A-Z]{3,4})\s?(.*)/i) {
                sendcontrol "500 '$_': command not understood.\r\n";
                last;
            }
            $FTPCMD=$1;
            $FTPARG=$2;
        }
                 
        logmsg "< \"$full\"\n";

        if($verbose) {
            print STDERR "IN: $full\n";
        }

        my $delay = $delayreply{$FTPCMD};
        if($delay) {
            # just go sleep this many seconds!
            logmsg("Sleep for $delay seconds\n");
            sleep($delay);
        }

        my $text;
        $text = $customreply{$FTPCMD};
        my $fake = $text;
        if($text eq "") {
            $text = $displaytext{$FTPCMD};
        }
        else {
            if($customcount{$FTPCMD} && (!--$customcount{$FTPCMD})) {
                # used enough number of times, now blank the customreply
                $customreply{$FTPCMD}="";
            }
        }
        my $check;
        if($text) {
            sendcontrol "$cmdid$text\r\n";
        }
        else {
            $check=1; # no response yet
        }

        if($fake eq "") {
            # only perform this if we're not faking a reply
            my $func = $commandfunc{$FTPCMD};
            if($func) {
                &$func($FTPARG, $FTPCMD);
                $check=0; # taken care of
            }
        }

        if($check) {
            logmsg "$FTPCMD wasn't handled!\n";
            sendcontrol "500 $FTPCMD is not dealt with!\r\n";
        }
            
    } # while(1)
    logmsg "====> Client disconnected\n";

    if($serverlogslocked) {
        $serverlogslocked = 0;
        clear_advisor_read_lock($SERVERLOGS_LOCK);
    }
}

print SFWRITE "QUIT\n";
waitpid $sfpid, 0;

unlink($pidfile);

if($serverlogslocked) {
    $serverlogslocked = 0;
    clear_advisor_read_lock($SERVERLOGS_LOCK);
}

exit;