Name

ftpd - Tcl FTP server implementation

Table Of Contents

• Table Of Contents
• Synopsis
• Description
• COMMANDS
• CALLBACKS
• VARIABLES
• Bugs, Ideas, Feedback
• Keywords
• Category

Synopsis

Description

The ftpd package provides a simple Tcl-only server library for the FTP protocol as specified in RFC 959 (http://www.rfc-editor.org/rfc/rfc959.txt). It works by listening on the standard FTP socket. Most server errors are returned as error messages with the appropriate code attached to them. Since the server code for the ftp daemon is executed in the event loop, it is possible that a bgerror will be thrown on the server if there are problems with the code in the module.

COMMANDS

::ftpd::server ?myaddr?

Open a listening socket to listen to and accept ftp connections. myaddr is an optional argument. myaddr is the domain-style name or numerical IP address of the client-side network interface to use for the connection.

::ftpd::config ?option value? ?option value ...?

The value is always the name of the command to call as the callback. The option specifies which callback should be configured. See section CALLBACKS for descriptions of the arguments and return values for each of the callbacks.

-authIpCmd proc

Callback to authenticate new connections based on the ip-address of the peer.

-authUsrCmd proc

Callback to authenticate new connections based on the user logging in (and the users password).

-authFileCmd proc

Callback to accept or deny a users access to read and write to a specific path or file.

-logCmd proc

Callback for log information generated by the FTP engine.

-fsCmd proc

Callback to connect the engine to the filesystem it operates on.

-closeCmd proc

Callback to be called when a connection is closed. This allows the embedding application to perform its own cleanup operations.

-xferDoneCmd proc

Callback for transfer completion notification. In other words, it is called whenever a transfer of data to or from the client has completed.

CALLBACKS

authIpCmd callback

The authIpCmd receives the ip-address of the peer attempting to connect to the ftp server as its argument. It returns a 1 to allow users from the specified IP to attempt to login and a 0 to reject the login attempt from the specified IP.

authUsrCmd callback

The authUsrCmd receives the username and password as its two arguments. It returns a 1 to accept the attempted login to the ftpd and a 0 to reject the attempted login.

authFileCmd callback

The authFileCmd receives the user (that is currently logged in), the path or filename that is about to be read or written, and read or write as its three arguments. It returns a 1 to allow the path or filename to be read or written, and a 0 to reject the attempted read or write with a permissions error code.

logCmd callback

The logCmd receives a severity and a message as its two arguments. The severities used within the ftpd package are note, debug, and error. The logCmd doesn't return anything.

fsCmd callback

The fsCmd receives a subcommand, a filename or path, and optional additional arguments (depending on the subcommand).

The subcommands supported by the fsCmd are:

fsCmd append path

The append subcommand receives the filename to append to as its argument. It returns a writable tcl channel as its return value.

fsCmd delete path channel

The delete subcommand receives the filename to delete, and a channel to write to as its two arguments. The file specified is deleted and the appropriate ftp message is written to the channel that is passed as the second argument. The delete subcommand returns nothing.

fsCmd dlist path style channel

The dlist subcommand receives the path that it should list the files that are in, the style in which the files should be listed which is either nlst or list, and a channel to write to as its three arguments. The files in the specified path are printed to the specified channel one per line. If the style is nlst only the name of the file is printed to the channel. If the style is list then the file permissions, number of links to the file, the name of the user that owns the file, the name of the group that owns the file, the size (in bytes) of the file, the modify time of the file, and the filename are printed out to the channel in a formatted space separated format. The dlist subcommand returns nothing.

fsCmd exists path

The exists subcommand receives the name of a file to check the existence of as its only argument. The exists subcommand returns a 1 if the path specified exists and the path is not a directory.

fsCmd mkdir path channel

The mkdir subcommand receives the path of a directory to create and a channel to write to as its two arguments. The mkdir subcommand creates the specified directory if necessary and possible. The mkdir subcommand then prints the appropriate success or failure message to the channel. The mkdir subcommand returns nothing.

fsCmd mtime path channel

The mtime subcommand receives the path of a file to check the modify time on and a channel as its two arguments. If the file exists the mtime is printed to the channel in the proper FTP format, otherwise an appropriate error message and code are printed to the channel. The mtime subcommand returns nothing.

fsCmd permissions path

The permissions subcommand receives the path of a file to retrieve the permissions of. The permissions subcommand returns the octal file permissions of the specified file. The file is expected to exist.

fsCmd rename path newpath channel

The rename subcommand receives the path of the current file, the new file path, and a channel to write to as its three arguments. The rename subcommand renames the current file to the new file path if the path to the new file exists, and then prints out the appropriate message to the channel. If the new file path doesn't exist the appropriate error message is printed to the channel. The rename subcommand returns nothing.

fsCmd retr path

The retr subcommand receives the path of a file to read as its only argument. The retr subcommand returns a readable channel that the specified file can be read from.

fsCmd rmdir path channel

The rmdir subcommand receives the path of a directory to remove and a channel to write to as its two arguments. The rmdir subcommand removes the specified directory (if possible) and prints the appropriate message to the channel (which may be an error if the specified directory does not exist or is not empty). The rmdir subcommand returns nothing.

fsCmd size path channel

The size subcommand receives the path of a file to get the size (in bytes) of and a channel to write to as its two arguments. The size subcommand prints the appropriate code and the size of the file if the specified path is a file, otherwise an appropriate error code and message are printed to the channel. The size subcommand returns nothing.

fsCmd store path

The store subcommand receives the path of a file to write as its only argument. The store subcommand returns a writable channel.

closeCmd

The closeCmd receives no arguments when it is invoked, and any return value it may generate is discarded.

xferDoneCmd sock sock2 file bytes filename err

The xferDoneCmd receives six arguments when invoked. These are, in this order, the channel handle of the control socket for the connection, the channel handle of the data socket used for the transfer (already closed), the handle of the channel containing the transfered file, the number of bytes transfered, the path of the file which was transfered, and a (possibly empty) error message. Any return value it may generate is discarded.

VARIABLES

::ftpd::cwd

The current working directory for a session when someone first connects to the FTPD or when the REIN ftp command is received.

::ftpd::contact

The e-mail address of the person that is the contact for the ftp server. This address is printed out as part of the response to the FTP HELP command.

::ftpd::port

The port that the ftp server should listen on. If port is specified as zero, the operating system will allocate an unused port for use as a server socket; afterwards, the variable will contain the port number that was allocated.

::ftpd::welcome

The message that is printed out when the user first connects to the ftp server.

::ftpd::CurrentSocket

Accessible to all callbacks and all filesystem commands (which are a special form of callback) and contains the handle of the socket channel which was active when the callback was invoked.

Bugs, Ideas, Feedback

This document, and the package it describes, will undoubtedly contain bugs and other problems. Please report such in the category ftpd of the Tcllib Trackers. Please also report any ideas for enhancements you may have for either package and/or documentation.

When proposing code changes, please provide unified diffs, i.e the output of diff -u.

Note further that attachments are strongly preferred over inlined patches. Attachments can be made by going to the Edit form of the ticket immediately after its creation, and then using the left-most button in the secondary navigation bar.

Keywords

ftp, ftpd, ftpserver, rfc 959, services

Category

Networking