ProFTPD Developer's Guide: Handlers

ProFTPD Version 1.2

Table of Contents

There are three main types of handler functions for ProFTPD: configuration directive handlers, command handlers, and authentication handlers.

Configuration Handlers
Configuration handlers are used to process the configuration directives encountered in the main proftpd.conf configuration file, any Included configuration files, and any .ftpaccess files encountered. The context in which these functions operate is one without connected clients; much of the "processing" entails syntax and availability checks of directive arguments, and the setting of configuration records.

Command Handlers
The command handlers are responsible for the processing of the client-sent FTP commands; these are the heart of the server, providing the services requested by the connecting user.

Authentication Handlers
The last type, authentication handlers, are not really handlers so much as they are replacement functions, to be used by ProFTPD for the purposes of authentication in place of the system or library provided functions. These types of functions are not as frequently used as the other two types of functions. For the curious reader, however, the sources for mod_ldap, mod_auth_pam, and mod_auth_unix illustrate how these functions are implemented; note that the tracing of the calling of these functions in the course of a live connection can be tricky.

Response Handlers
While not quite true handlers, per se, the response functions are also important piece of module handler development. These functions deal with how ProFTPD sends its responses back to the connecting clients.

Handler Macros
There are also several pre-defined macros to help in the checking of various handler argument conditions, such as argument number and syntax. These macros are described here.

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Author: $Author: castaglia $
Last Updated: $Date: 2003/04/25 15:42:55 $

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