Why am I here?

To turn you into a libyahoo2 hacker

A brief history of IM

• gAIM (Mark Spencer)
• gaim2 and everybuddy (Torrey Searle)
• gaiming the system (Rob Flynn)
• everyone else joins in

chmod +wx bluesmoon

• In late 2000, I started using everybuddy - my first IM
• Fixed a few bugs in the Yahoo! code in Jan 2001
• In March 2001, I'd unknowingly become maintainer of the Yahoo! plugin
• In December 2002, Colin, Meredydd and I forked everybuddy into ayttm and eb-lite

Protocols and the catch-up gaim

• In March 2001, Yahoo! changed their authentication protocol - tested in India!
• Everyone tried to break it, Sean Egan does it first for gaim
• I ported gaim's Yahoo! code to everybuddy
• The code worked as a standalone library
• Still distributed as part of everybuddy codebase

fresh meat

• gaim did not plan on releasing yahoo code as a library
• split libyahoo2 out of everybuddy into a separate project
• announce on freshmeat (22^nd July, 2002)
• downloads start immediately (avg 100 per month)

building the community

• Mailing list gets active from Oct 2002, downloads to 300/m
• Rodney Dawes helps with autofoo funk
• Kopete (Duncan), Fire (Alan), Miranda (Gena), CenterICQ (Konst) come on board
• Tim Ringenbach merges code back into gaim (Controversy)

pedantics

• Rules for writing libyahoo2 code
  • Must be pure C (no C++)
  • Must compile with -ansi -pedantic
  • Must not assume byte order or word size
  • Don't pollute namespaces as far as possible
  • Document all APIs well (loosely doxygen style)

• No copyright sign-off on submitted code

tech talk

• data structures
• callback structure
• async pink
• utilities
• logging

data structures

• Borrowed heavily from gaim - at the start
• yahoo2_types.h
  • yahoo_data and yahoo_buddy
  • addressbook
  • types for callback function
  • several enums and #defines

callback structure

• callback structure or callback functions (YAHOO_CALLBACK_TYPE)
• structure doesn't pollute namespace
• all callbacks MUST be defined
• yahoo2_callbacks.h
  • ext_*

unsynching

• built to be asynchronous
• all calls that are expected to block take in a callback function and callback data
• ext_yahoo_add_handler, yahoo_read_ready and yahoo_write_ready

utilities

• Conditionally implemented libraries from glib to drop dependency
  • YList
  • y_new, y_new0, y_renew, y_memdup, y_strsplit, etc.

• http library
  • yahoo_tcp_readline
  • yahoo_http_post, yahoo_http_get, yahoo_get_url_fd
  • yahoo_urlencode, yahoo_urldecode

logging

• 7 log levels
• NONE=0, FATAL, ERR, WARNING, NOTICE, INFO, DEBUG=6
• Verbosity increases from left to right
• log_level=DEBUG for webcams inspired screens in the matrix

given enough eyeballs...

• security vuln, stack corruption possible
• memory leak in yahoo_process_auth_0x0b
• Memory leak in yahoo_process_chat

...and features too

• Michaël Kamp adds webcam support
• Wayne Parrott adds chatroom support
• Wilmer van der Gaast fixes auth and leaks
• Matt Rogers and Ben Reser help with 64bit
• Gena pulls in stuff from Miranda
• Konst adds Yahoo! Search

Letting go

• March 2004 I have to quit the project
• Project is stable and requires no maintenance
• Craig West chips in till August 2004 (last release)
• 2006 — Gennady Feldman takes over as maintainer
• This week (2006/11/21), Kartik Mistry joins as Debian release technician

What's needed now?

• Only 75% done (hence version 0.7.5)
• Voice support
• IMVironments, Audibles and Avatars
• Stealth
• What's your most desired feature? Add it!

Why should you work on it?

• There is a lot to learn
• The community is full of really smart people
• The user base is exponential
• The thrill of looking at someone's desktop and thinking, deep down, that's my code you're running.
• Get your picture in the paper, and maybe on television too

libyahoo2

http://libyahoo2.sourceforge.net/

libyahoo2-users@lists.sourceforge.net

Greetz

• The great Torrey Searle for being such an inspiration
• My friend, Colin Leroy for doing everything else on ayttm
• Madhu M Kurup

Note: The background image on these slides is a webcam packet capture. Manish contends that it's of my nose.