README

A LKL and APR based FTP daemon.


Prerequisites:
	a) APR library - The Apache Portable Runtime Library.
		- a set of minimalistic C wrappers over system calls
		  that permits writing portable and fast code in C.
		- on Debian/Ubuntu just do [sudo] apt-get install libapr1-dev.
		  You'll need to install the "-dev" package to get the header files.
		  LKLFTPD (currently) looks for the headers in /usr/include/apr-1.0/;
		  you may need to tweak this on your system.
		- a 1.2.1 or better version will do just fine (but later versions
		  have more bugfixes and better support for some platforms).
	b) A multi-threaded operating system.
		LKLFTPD starts at least one new thread per client.
	c) LKL - if you want to run LKLFTPD through LKL you'll obviously need LKL.
		- check on http://cs.pub.ro/~ixlabs/?page_id=134 for details about LKL.

Documentation:
	a) APR - http://apr.apache.org/docs/apr/1.2/modules.html
	b) LKL - http://cs.pub.ro/~ixlabs/?page_id=134


Design:
	LISTENER-THREAD - main thread
	- waits for connection on a given TCP port (standart default: 21).
	WORKER-THREADS - for each accepted connection we start a new thread.
	- all commands issued by the client are handled on this separate thread.
	- for data transmissions other threads may be started durring the
	  lifetime of the client
	- data relevant to the connection is held in a lfd_sess structure,
	  and a pointer to this structure is passed to all functions
	  called from the connection command loop.



LKL:
	To aid developement and o give LKLFTPD more functionality we have wrapped
	  all file IO functions under lkl_file_t based operations.
	These are by default mapped "1-1" to apr_file_t, but by defining LKL_FILE_APIS at
	  compile time you can use lkl based file IO.
	a) If LKL_FILE_APIS is NOT DEFINED (which means lkl_file_t is defined as apr_file_t)
	     you will use the OS APIs to access files.
	     No LKL code is run/called. You need not link to liblkl.
	     In this mode you can use LKLFTPD as a standalone ftp server.
	b) If LKL_FILE_APIS is DEFINED, lkl_file_t is implemented as a wrapper
	     over LKL's sys_* functions. In this mode you'll need to link to LKL.
	     You'll be bound to Linux' licence (currently GPLv2) by linking
	     directly to Linux code.