InfoMagic Internet Tools 1993 July/Internet Tools.iso/RockRidge/archival/mirror-2.1/ftp.pl

Perl Script | 1993-06-28 | 23.4 KB | 1,256 lines

#-*-perl-*-
# This is a wrapper to the chat2.pl routines that make life easier
# to do ftp type work.
# Mostly by Lee McLoughlin <[e-mail]>
# based on original version by Alan R. Martello <[e-mail]>
# And by [e-mail] for multi-homed hosts
#
# Basic usage:
#  $ftp_port = 21;
#  $retry_call = 1;
#  $attempts = 2;
#  if( &ftp'open( $site, $ftp_port, $retry_call, $attempts ) != 1 ){
#   die "failed to open ftp connection";
#  }
#  if( ! &ftp'login( $user, $pass ) ){
#   die "failed to login";
#  }
#  &ftp'type( $text_mode ? 'A' : 'I' );
#  if( ! &ftp'get( $remote_filename, $local_filename, 0 ) ){
#   die "failed to get file;
#  }
#  &ftp'quit();
#
#
# $Id: ftp.pl,v 2.1 1993/06/28 15:02:00 lmjm Exp lmjm $
# $Log: ftp.pl,v $
# Revision 2.1  1993/06/28  15:02:00  lmjm
# Full 2.1 release
#
#

require 'chat2.pl';
require 'socket.ph';


package ftp;

if( defined( &main'PF_INET ) ){
    $pf_inet = &main'PF_INET;
    $sock_stream = &main'SOCK_STREAM;
    local($name, $aliases, $proto) = getprotobyname( 'tcp' );
    $tcp_proto = $proto;
}
else {
    # XXX hardwired $PF_INET, $SOCK_STREAM, 'tcp'
    # but who the heck would change these anyway? (:-)
    $pf_inet = 2;
    $sock_stream = 1;
    $tcp_proto = 6;
}

# If the remote ftp daemon doesn't respond within this time presume its dead
# or something.
$timeout = 120;

# Timeout a read if I don't get data back within this many seconds
$timeout_read = 3 * $timeout;

# Timeout an open
$timeout_open = $timeout;

$ftp'version = '$Revision: 2.1 $';

# This is a "global" it contains the last response from the remote ftp server
# for use in error messages
$ftp'response = "";
# Also ftp'NS is the socket containing the data coming in from the remote ls
# command.

# The size of block to be read or written when talking to the remote
# ftp server
$ftp'ftpbufsize = 4096;

# How often to print a hash out, when debugging
$ftp'hashevery = 1024;
# Output a newline after this many hashes to prevent outputing very long lines
$ftp'hashnl = 70;

# Is there a connection open?
$ftp'service_open = 0;

# If a proxy connection then who am I really talking to?
$real_site = "";

# Where error/log reports are sent to
$ftp'showfd = 'STDERR';

# Name of a function to call on a pathname to map it into a remote
# pathname.
$ftp'mapunixout = '';
$ftp'manunixin = '';

# This is just a tracing aid.
$ftp_show = 0;

sub ftp'debug
{
    $ftp_show = @_[0];
    if( $ftp_show > 9 ){
        $chat'debug = 1;
    }
}

sub ftp'set_timeout
{
    local( $to ) = @_;
    return if $to == $timeout;
    $timeout = $to;
    $timeout_open = $timeout;
    $timeout_read = 3 * $timeout;
    if( $ftp_show ){
        print $ftp'showfd "ftp timeout set to $timeout\n";
    }
}


sub ftp'open_alarm
{
    die "timeout: open";
}

sub ftp'timed_open
{
    local( $site, $ftp_port, $retry_call, $attempts ) = @_;
    local( $connect_site, $connect_port );
    local( $res );

    alarm( $timeout_open );

    while( $attempts-- ){
        if( $ftp_show ){
            print $ftp'showfd "proxy connecting via $proxy_gateway [$proxy_ftp_port]\n" if $proxy;
            print $ftp'showfd "Connecting to $site";
            if( $ftp_port != 21 ){
                print $ftp'showfd " [port $ftp_port]";
            }
            print $ftp'showfd "\n";
        }

        if( $proxy ) {
            if( ! $proxy_gateway ) {
                # if not otherwise set
                $proxy_gateway = "internet-gateway";
            }
            if( $debug ) {
                print $ftp'showfd "using proxy services of $proxy_gateway, ";
                print $ftp'showfd "at $proxy_ftp_port\n";
            }
            $connect_site = $proxy_gateway;
            $connect_port = $proxy_ftp_port;
            $real_site = $site;
        }
        else {
            $connect_site = $site;
            $connect_port = $ftp_port;
        }
        if( ! &chat'open_port( $connect_site, $connect_port ) ){
            if( $retry_call ){
                print $ftp'showfd "Failed to connect\n" if $ftp_show;
                next;
            }
            else {
                print $ftp'showfd "proxy connection failed " if $proxy;
                print $ftp'showfd "Cannot open ftp to $connect_site\n" if $ftp_show;
                return 0;
            }
        }
        $res = &ftp'expect( $timeout,
            120, 0, # service unavailable to $site
            220, 1, # ready for login to $site
            421, 0); #service unavailable to $site closing connection
        if( ! $res ){
            &chat'close();
            next;
        }
        return 1;
    }
    continue {
        print $ftp'showfd "Pausing between retries\n";
        sleep( $retry_pause );
    }
    return 0;
}

sub main'ftp__sighandler
{
    local( $sig ) = @_;
    local( $msg ) = "Caught a SIG$sig flagging connection down";
    $ftp'service_open = 0;
    if( $ftp_logger ){
        eval "&$ftp_logger( \$msg )";
    }
}

sub ftp'set_signals
{
    $ftp_logger = @_;
    $SIG{ 'PIPE' } = "ftp__sighandler";
}

# Set the mapunixout and mapunixin functions
sub ftp'set_namemap
{
    ($ftp'mapunixout, $ftp'mapunixin) = @_;
    if( $debug ) {
        print $ftp'showfd "mapunixout = $ftp'mapunixout, $mapunixin = $ftp'mapunixin\n";
    }
}


sub ftp'open
{
    local( $site, $ftp_port, $retry_call, $attempts ) = @_;

    local( $old_sig ) = $SIG{ 'ALRM' };
    $SIG{ 'ALRM' } = "ftp\'open_alarm";

    local( $ret ) = eval "&timed_open( '$site', $ftp_port, $retry_call, $attempts )";
    alarm( 0 );
    $SIG{ 'ALRM' } = $old_sig;

    if( $@ =~ /^timeout/ ){
        return -1;
    }

    if( $ret ){
        $ftp'service_open = 1;
    }

    return $ret;
}

sub ftp'login
{
    local( $remote_user, $remote_password ) = @_;
        local( $ret );

    if( ! $ftp'service_open ){
        return 0;
    }

    if( $proxy ){
        &ftp'send( "USER $remote_user@$site" );
    }
    else {
        &ftp'send( "USER $remote_user" );
    }
    $ret = &ftp'expect( $timeout,
        230, 1, # $remote_user logged in
        331, 2, # send password for $remote_user

        500, 0, # syntax error
        501, 0, # syntax error
        530, 0, # not logged in
        332, 0, # account for login not supported

        421, 99 ); # service unavailable, closing connection
    if( $ret == 99 ){
        &service_closed();
        $ret = 0;
    }
    if( $ret == 1 ){
        # Logged in no password needed
        return 1;
    }
    elsif( $ret == 2 ){
        # A password is needed
        &ftp'send( "PASS $remote_password" );

        $ret = &ftp'expect( $timeout,
            230, 1, # $remote_user logged in

            202, 0, # command not implemented
            332, 0, # account for login not supported

            530, 0, # not logged in
            500, 0, # syntax error
            501, 0, # syntax error
            503, 0,  # bad sequence of commands

            421, 99 ); # service unavailable, closing connection
        if( $ret == 99 ){
            &service_closed();
            $ret = 0;
        }
        if( $ret == 1 ){
            # Logged in
            return 1;
        }
    }
    # If I got here I failed to login
    return 0;
}

sub service_closed
{
    $ftp'service_open = 0;
    &chat'close();
}

sub ftp'close
{
    &ftp'quit();
    $ftp'service_open = 0;
    &chat'close();
}

# Change directory
# return 1 if successful
# 0 on a failure
sub ftp'cwd
{
    local( $dir ) = @_;
    local( $ret );

    if( ! $ftp'service_open ){
        return 0;
    }

    if( $ftp'mapunixout ){
        $dir = eval "&$ftp'mapunixout( \$dir, 'd' )";
    }

    &ftp'send( "CWD $dir" );

    $ret = &ftp'expect( $timeout,
        200, 1, # working directory = $dir
        250, 1, # working directory = $dir

        500, 0, # syntax error
        501, 0, # syntax error
                502, 0, # command not implemented
        530, 0, # not logged in
                550, 0, # cannot change directory
        421, 99 ); # service unavailable, closing connection

    if( $ret == 99 ){
        &service_closed();
        $ret = 0;
    }

    return $ret;
}

# Get a full directory listing:
# &ftp'dir( remote LIST options )
# Start a list going with the given options.
# Presuming that the remote deamon uses the ls command to generate the
# data to send back then then you can send it some extra options (eg: -lRa)
# return 1 if sucessful and 0 on a failure
sub ftp'dir_open
{
    local( $options ) = @_;
    local( $ret );

    if( ! $ftp'service_open ){
        return 0;
    }

    if( ! &ftp'open_data_socket() ){
        return 0;
    }

    if( $options ){
        &ftp'send( "LIST $options" );
    }
    else {
        &ftp'send( "LIST" );
    }

    $ret = &ftp'expect( $timeout,
        150, 1, # reading directory

        125, 0, # data connection already open?

        450, 0, # file unavailable
        500, 0, # syntax error
        501, 0, # syntax error
        502, 0, # command not implemented
        530, 0, # not logged in

            421, 99 ); # service unavailable, closing connection
    if( $ret == 99 ){
        &service_closed();
        $ret = 0;
    }

    if( ! $ret ){
        &ftp'close_data_socket;
        return 0;
    }

    accept( NS, S ) || die "accept failed $!";

    #
    # the data should be coming at us now
    #

    return 1;
}


# Close down reading the result of a remote ls command
# return 1 if successful and 0 on failure
sub ftp'dir_close
{
    local( $ret );

    if( ! $ftp'service_open ){
        return 0;
    }

    # read the close
    #
    $ret = &ftp'expect($timeout,
            226, 1, # transfer complete, closing connection
            250, 1, # action completed

            425, 0, # can't open data connection
            426, 0, # connection closed, transfer aborted
            451, 0, # action aborted, local error
            421, 99 ); # service unavailable, closing connection
    if( $ret == 99 ){
        &service_closed();
        $ret = 0;
    }

    # shut down our end of the socket
    &ftp'close_data_socket;

    if( ! $ret ){
        return 0;
    }

    return 1;
}

# Quit from the remote ftp server
# return 1 if successful and 0 on failure
sub ftp'quit
{
    local( $ret );

    $site_command_check = 0;
    @site_command_list = ();

    if( ! $ftp'service_open ){
        return 0;
    }

    &ftp'send( "QUIT" );

    $ret = &ftp'expect( $timeout,
        221, 1, # transfer complete, closing connection
        500, 0, # error quitting??
        421, 99 ); # service unavailable, closing connection
    if( $ret == 99 ){
        &service_closed();
        $ret = 0;
    }
    return $ret;
}

sub ftp'read_alarm
{
    die "timeout: read";
}

sub ftp'timed_read
{
    alarm( $timeout_read );

    return sysread( NS, $ftpbuf, $ftpbufsize );
}

sub ftp'read
{
    $SIG{ 'ALRM' } = "ftp\'read_alarm";

    if( ! $ftp'service_open ){
        return -1;
    }

    local( $ret ) = eval '&timed_read()';
    alarm( 0 );

    if( $@ =~ /^timeout/ ){
        return -1;
    }
    return $ret;
}

# Get a remote file back into a local file.
# If no loc_fname passed then uses rem_fname.
# returns 1 on success and 0 on failure
sub ftp'get
{
    local($rem_fname, $loc_fname, $restart ) = @_;
    local( $ret );

    if( ! $ftp'service_open ){
        return 0;
    }

    if( $loc_fname eq "" ){
        $loc_fname = $rem_fname;
    }

    if( ! &ftp'open_data_socket() ){
        print $ftp'showfd "Cannot open data socket\n";
        return 0;
    }

    if( $loc_fname ne '-' ){
        # Find the size of the target file
        local( $restart_at ) = &ftp'filesize( $loc_fname );
        if( $restart && $restart_at > 0 && &ftp'restart( $restart_at ) ){
            $restart = 1;
            # Make sure the file can be updated
            chmod( 0644, $loc_fname );
        }
        else {
            $restart = 0;
            unlink( $loc_fname );
        }
    }

    if( $ftp'mapunixout ){
        $rem_fname = eval "&$ftp'mapunixout( \$rem_fname, 'f' )";
    }

    &ftp'send( "RETR $rem_fname" );

    $ret = &ftp'expect( $timeout,
        150, 1, # receiving $rem_fname

        125, 0, # data connection already open?
        450, 2, # file unavailable
        550, 2, # file unavailable
        500, 0, # syntax error
        501, 0, # syntax error
        530, 0, # not logged in

        421, 99 ); # service unavailable, closing connection
    if( $ret == 99 ){
        &service_closed();
        $ret = 0;
    }
    if( $ret != 1 ){
        print $ftp'showfd "Failure on 'RETR $rem_fname' command\n";

        # shut down our end of the socket
        &ftp'close_data_socket;

        return 0;
    }

    accept( NS, S ) || die "accept failed $!";

    #
    # the data should be coming at us now
    #

    #
    #  open the local fname
    #  concatenate on the end if restarting, else just overwrite
    if( !open( FH, ($restart ? '>>' : '>') . $loc_fname ) ){
        print $ftp'showfd "Cannot create local file $loc_fname\n";

        # shut down our end of the socket
        &ftp'close_data_socket;

        return 0;
    }

    local( $start_time ) = time;
    local( $bytes, $lasthash, $hashes ) = (0, 0, 0);
    while( ($len = &ftp'read()) > 0 ){
        $bytes += $len;
        if( $strip_cr ){
            $ftp'buf =~ s/\r//g;
        }
        if( $ftp_show ){
            while( $bytes > ($lasthash + $ftp'hashevery) ){
                print $ftp'showfd '#';
                $lasthash += $ftp'hashevery;
                $hashes++;
                if( ($hashes % $ftp'hashnl) == 0 ){
                    print $ftp'showfd "\n";
                }
            }
        }
        if( ! print FH $ftp'ftpbuf ){
            print $ftp'showfd "\nfailed to write data";
            $bytes = -1;
            last;
        }
    }
    close( FH );

    # shut down our end of the socket
    &ftp'close_data_socket;

    if( $len < 0 ){
        print $ftp'showfd "\ntimed out reading data!\n";

        return 0;
    }

    if( $ftp_show && $bytes > 0 ){
        if( $hashes && ($hashes % $ftp'hashnl) != 0 ){
            print $ftp'showfd "\n";
        }
        local( $secs ) = (time - $start_time);
        if( $secs <= 0 ){
            $secs = 1; # To avoid a divide by zero;
        }

        local( $rate ) = int( $bytes / $secs );
        print $ftp'showfd "Got $bytes bytes ($rate bytes/sec)\n";
    }

    #
    # read the close
    #

    $ret = &ftp'expect( $timeout,
        226, 1, # transfer complete, closing connection
            250, 1, # action completed

            110, 0, # restart not supported
            425, 0, # can't open data connection
            426, 0, # connection closed, transfer aborted
            451, 0, # action aborted, local error
        550, 0, # permission denied

        421, 99 ); # service unavailable, closing connection
    if( $ret == 99 ){
        &service_closed();
        $ret = 0;
    }

    if( $ret && $bytes < 0 ){
        $ret = 0;
    }

    return $ret;
}

sub ftp'delete
{
    local( $rem_fname ) = @_;
    local( $ret );

    if( ! $ftp'service_open ){
        return 0;
    }

    if( $ftp'mapunixout ){
        $rem_fname = eval "&$ftp'mapunixout( \$rem_fname, 'f' )";
    }

    &ftp'send( "DELE $rem_fname" );

    $ret = &ftp'expect( $timeout,
        250, 1, # Deleted $rem_fname
        550, 0, # Permission denied

        421, 99 ); # service unavailable, closing connection
    if( $ret == 99 ){
        &service_closed();
        $ret = 0;
    }

    return $ret == 1;
}

sub ftp'deldir
{
    local( $fname ) = @_;

    # not yet implemented
    # RMD
}

# UPDATE ME!!!!!!
# Add in the hash printing and newline conversion
sub ftp'put
{
    local( $loc_fname, $rem_fname ) = @_;
    local( $strip_cr );

    if( ! $ftp'service_open ){
        return 0;
    }

    if( $loc_fname eq "" ){
        $loc_fname = $rem_fname;
    }

    if( ! &ftp'open_data_socket() ){
        return 0;
    }

    if( $ftp'mapunixout ){
        $rem_fname = eval "&$ftp'mapunixout( \$rem_fname, 'f' )";
    }

    &ftp'send( "STOR $rem_fname" );

    #
    # the data should be coming at us now
    #

    local( $ret ) =
    &ftp'expect( $timeout,
        150, 1, # sending $loc_fname

        125, 0, # data connection already open?
        450, 0, # file unavailable
        532, 0, # need account for storing files
        452, 0, # insufficient storage on system
        553, 0, # file name not allowed
        500, 0, # syntax error
        501, 0, # syntax error
        530, 0, # not logged in

        421, 99 ); # service unavailable, closing connection
    if( $ret == 99 ){
        &service_closed();
        $ret = 0;
    }

    if( $ret != 1 ){
        # shut down our end of the socket
        &ftp'close_data_socket;

        return 0;
    }


    accept( NS, S ) || die "accept failed $!";

    #
    # the data should be coming at us now
    #

    #
    #  open the local fname
    #
    if( !open( FH, "<$loc_fname" ) ){
        print $ftp'showfd "Cannot open local file $loc_fname\n";

        # shut down our end of the socket
        &ftp'close_data_socket;

        return 0;
    }

    while( <FH> ){
        if( ! $ftp'service_open ){
            last;
        }
        print NS ;
    }
    close( FH );

    # shut down our end of the socket to signal EOF
    &ftp'close_data_socket;

    #
    # read the close
    #

    $ret = &ftp'expect( $timeout,
        226, 1, # transfer complete, closing connection
        250, 1, # action completed

        110, 0, # restart not supported
        425, 0, # can't open data connection
        426, 0, # connection closed, transfer aborted
        451, 0, # action aborted, local error
        551, 0, # page type unknown
        552, 0, # storage allocation exceeded

        421, 99 ); # service unavailable, closing connection
    if( $ret == 99 ){
        &service_closed();
        $ret = 0;
    }
    if( ! $ret ){
        print $ftp'showfd "Failure on 'STOR $loc_fname' command\n";
    }
    return $ret;
}

sub ftp'restart
{
    local( $restart_point, $ret ) = @_;

    if( ! $ftp'service_open ){
        return 0;
    }

    &ftp'send( "REST $restart_point" );

    #
    # see what they say

    $ret = &ftp'expect( $timeout,
        350, 1, # restarting at $restart_point

        500, 0, # syntax error
        501, 0, # syntax error
        502, 2, # REST not implemented
        530, 0, # not logged in
        554, 2, # REST not implemented

        421, 99 ); # service unavailable, closing connection
    if( $ret == 99 ){
        &service_closed();
        $ret = 0;
    }
    return $ret;
}

# Set the file transfer type
sub ftp'type
{
    local( $type ) = @_;

    if( ! $ftp'service_open ){
        return 0;
    }

    &ftp'send( "TYPE $type" );

    #
    # see what they say

    $ret = &ftp'expect( $timeout,
        200, 1, # file type set to $type

        500, 0, # syntax error
        501, 0, # syntax error
        504, 0, # Invalid form or byte size for type $type

        421, 99 ); # service unavailable, closing connection
    if( $ret == 99 ){
        &service_closed();
        $ret = 0;
    }
    return $ret;
}

$site_command_check = 0;
@site_command_list = ();

# routine to query the remote server for 'SITE' commands supported
sub ftp'site_commands
{
    local( $ret );

    if( ! $ftp'service_open ){
        return 0;
    }

    # if we havent sent a 'HELP SITE', send it now
    if( !$site_command_check ){

        $site_command_check = 1;

        &ftp'send( "HELP SITE" );

        # assume the line in the HELP SITE response with the 'HELP'
        # command is the one for us
        $ret = &ftp'expect( $timeout,
            ".*HELP.*", "\$1",
            214, "0",
            202, "0",
            421, "99" ); # service unavailable, closing connection
        if( $ret == 99 ){
            &service_closed();
            $ret = "0";
        }

        if( $ret eq "0" ){
            print $ftp'showfd "No response from HELP SITE\n" if( $ftp_show );
        }

        @site_command_list = split(/\s+/, $ret);
    }

    return @site_command_list;
}

# return the pwd, or null if we can't get the pwd
sub ftp'pwd
{
    local( $ret, $cwd );

    if( ! $ftp'service_open ){
        return 0;
    }

    &ftp'send( "PWD" );

    #
    # see what they say

    $ret = &ftp'expect( $timeout,
        257, 1, # working dir is
        500, 0, # syntax error
        501, 0, # syntax error
        502, 0, # PWD not implemented
        550, 0, # file unavailable

        421, 99 ); # service unavailable, closing connection
    if( $ret == 99 ){
        &service_closed();
        $ret = 0;
    }
    if( $ret ){
        if( $ftp'response =~ /^257\s"(.*)"\s.*$/ ){
            $cwd = $1;
        }
    }
    return $cwd;
}

# return 1 for success, 0 for failure
sub ftp'mkdir
{
    local( $path ) = @_;
    local( $ret );

    if( ! $ftp'service_open ){
        return 0;
    }

    if( $ftp'mapunixout ){
        $path = eval "&$ftp'mapunixout( \$path, 'f' )";
    }

    &ftp'send( "MKD $path" );

    #
    # see what they say

    $ret = &ftp'expect( $timeout,
        257, 1, # made directory $path

        500, 0, # syntax error
        501, 0, # syntax error
        502, 0, # MKD not implemented
        530, 0, # not logged in
        550, 0, # file unavailable

        421, 99 ); # service unavailable, closing connection
    if( $ret == 99 ){
        &service_closed();
        $ret = 0;
    }
    return $ret;
}

# return 1 for success, 0 for failure
sub ftp'chmod
{
    local( $path, $mode ) = @_;
    local( $ret );

    if( ! $ftp'service_open ){
        return 0;
    }

    if( $ftp'mapunixout ){
        $path = eval "&$ftp'mapunixout( \$path, 'f' )";
    }

    &ftp'send( sprintf( "SITE CHMOD %o $path", $mode ) );

    #
    # see what they say

    $ret = &ftp'expect( $timeout,
        200, 1, # chmod $mode $path succeeded

        500, 0, # syntax error
        501, 0, # syntax error
        502, 0, # CHMOD not implemented
        530, 0, # not logged in
        550, 0, # file unavailable

        421, 99 ); # service unavailable, closing connection
    if( $ret == 99 ){
        &service_closed();
        $ret = 0;
    }
    return $ret;
}

# rename a file
sub ftp'rename
{
    local( $old_name, $new_name ) = @_;
    local( $ret );

    if( ! $ftp'service_open ){
        return 0;
    }

    if( $ftp'mapunixout ){
        $old_name = eval "&$ftp'mapunixout( \$old_name, 'f' )";
    }

    &ftp'send( "RNFR $old_name" );

    #
    # see what they say

    $ret = &ftp'expect( $timeout,
        350, 1, #  OK

        500, 0, # syntax error
        501, 0, # syntax error
        502, 0, # RNFR not implemented
        530, 0, # not logged in
        550, 0, # file unavailable
        450, 0, # file unavailable

        421, 99 ); # service unavailable, closing connection
    if( $ret == 99 ){
        &service_closed();
        $ret = 0;
    }

    # check if the "rename from" occurred ok
    if( $ret ){
        if( $ftp'mapunixout ){
            $new_name = eval "&$ftp'mapunixout( \$new_name, 'f' )";
        }

        &ftp'send( "RNTO $new_name" );

        #
        # see what they say

        $ret = &ftp'expect( $timeout,
            250, 1,  # rename $old_name to $new_name

            500, 0, # syntax error
            501, 0, # syntax error
            502, 0, # RNTO not implemented
            503, 0, # bad sequence of commands
            530, 0, # not logged in
            532, 0, # need account for storing files
            553, 0, # file name not allowed

            421, 99 ); # service unavailable, closing connection
        if( $ret == 99 ){
            &service_closed();
            $ret = 0;
        }
    }

    return $ret;
}


sub ftp'quote
{
    local( $cmd ) = @_;
    local( $ret );

    if( ! $ftp'service_open ){
        return 0;
    }

    &ftp'send( $cmd );

    $ret = &ftp'expect( $timeout,
        200, 1, # Remote '$cmd' OK
        500, 0, # error in remote '$cmd'
        421, 99 ); # service unavailable, closing connection
    if( $ret == 99 ){
        &service_closed();
        $ret = 0;
    }
    return $ret;
}

# ------------------------------------------------------------------------------
# These are the lower level support routines

sub ftp'expectgot
{
    ($ftp'response, $ftp'fatalerror) = @_;
    if( $ftp_show ){
        print $ftp'showfd "$ftp'response\n";
    }
}

#
#  create the list of parameters for chat'expect
#
#  ftp'expect(time_out, {value, return value});
#  the last response is stored in $ftp'response
#
sub ftp'expect
{
    local( $ret );
    local( $time_out );
    local( @expect_args );
    local( $code, $pre );

    $ftp'response = '';
    $ftp'fatalerror = 0;

    $time_out = shift( @_ );

    while( @_ ){
        $code = shift( @_ );
        $pre = '^';
        if( $code =~ /^\d+$/ ){
            $pre = "[.|\n]*^";
        }
        push( @expect_args, "$pre(" . $code . " .*)\\015\\n" );
        push( @expect_args,
            "&expectgot( \$1, 0 ); " . shift( @_ ) );
    }

    # Treat all unrecognised lines as continuations
    push( @expect_args, "^(.*)\\015\\n" );
    push( @expect_args, "&expectgot( \$1, 0 ); 100" );

    # add patterns TIMEOUT and EOF

    push( @expect_args, 'TIMEOUT' );
    push( @expect_args, "&expectgot( 'timed out', 0 ); 0" );

    push( @expect_args, 'EOF' );
    push( @expect_args, "&expectgot( 'remote server gone away', 1 ); 99" );

    if( $ftp_show > 9 ){
        &printargs( $time_out, @expect_args );
    }

    $ret = &chat'expect( $time_out, @expect_args );
    if( $ret == 100 ){
        # we saw a continuation line, wait for the end
        push( @expect_args, "^.*\n" );
        push( @expect_args, "100" );

        while( $ret == 100 ){
            if( $ftp_show > 9 ){
                &printargs( $time_out, @expect_args );
            }
            $ret = &chat'expect( $time_out, @expect_args );
        }
    }

    return $ret;
}


#
#  opens NS for io
#
sub ftp'open_data_socket
{
    local( $sockaddr, $port );
    local( $type, $myaddr, $a, $b, $c, $d );
    local( $mysockaddr, $family, $hi, $lo );

    $sockaddr = 'S n a4 x8';

    ($a,$b,$c,$d) = unpack( 'C4', $chat'thisaddr );
    $this = $chat'thisproc;

    socket( S, $pf_inet, $sock_stream, $tcp_proto ) || die "socket: $!";
    bind( S, $this ) || die "bind: $!";

    # get the port number
    $mysockaddr = getsockname( S );
    ($family, $port, $myaddr) = unpack( $sockaddr, $mysockaddr );

    $hi = ($port >> 8) & 0x00ff;
    $lo = $port & 0x00ff;

    #
    # we MUST do a listen before sending the port otherwise
    # the PORT may fail
    #
    listen( S, 5 ) || die "listen";

    &ftp'send( "PORT $a,$b,$c,$d,$hi,$lo" );

    return &ftp'expect($timeout,
        200, 1, # PORT command successful
        250, 1, # PORT command successful

        500, 0, # syntax error
        501, 0, # syntax error
        530, 0, # not logged in

        421, 0); # service unavailable, closing connection
}

sub ftp'close_data_socket
{
    close( NS );
}

sub ftp'send
{
    local( $send_cmd ) = @_;

    if( $send_cmd =~ /\n/ ){
        print $ftp'showfd "ERROR, \\n in send string for $send_cmd\n";
    }

    if( $ftp_show ){
        local( $sc ) = $send_cmd;

        if( $send_cmd =~ /^PASS/){
            $sc = "PASS <somestring>";
        }
        print $ftp'showfd "---> $sc\n";
    }

    &chat'print( "$send_cmd\r\n" );
}

sub ftp'printargs
{
    while( @_ ){
        print $ftp'showfd shift( @_ ) . "\n";
    }
}

sub ftp'filesize
{
    local( $fname ) = @_;

    if( ! -f $fname ){
        return -1;
    }

    return (stat( _ ))[ 7 ];

}

# make this package return true
1;