2011-01-06

IPC cheatsheet for HelenOS

Sometimes as a last resort when debugging HelenOS you need to use the kernel console. If the problem has something to do with IPC, you will end deciphering the IPC communication with ipc command. If you also do not remember that 1031 means request to VFS for file closing, you might find the following cheat sheet useful.

In HelenOS, IPC methods are numbered and enums are used for these. That means that you cannot search the source code for particular number to find the method name. Thus, you would spent a lot of time counting what is the nth item to find out the name (to find out the corresponding handler). I had enough of that very soon. Thus I wanted to get a pencil and rewrite the names on a piece of paper. Well... I stopped even before writing down VFS methods because there are about 30 of them. So I decided to write a script for it...

The PDF I created can be downloaded here. The list is definitely not complete but contains the methods I was dealing with.

If you think the cheat sheet might be useful to you to and you want to extend it, the sources are available as well. I had them placed in /contrib/tools but there is not strict rule about it. You only need to set the PATH2ROOT variable in the Makefile when they are placed elsewhere.

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