Wireshark · Wireshark-users: Re: [Wireshark-users] Reading a zero-terminated string in Lua dissector

[Carsten Fuchs <carsten.fuchs@xxxxxxx>]

Hi Jeff,

thanks for your reply.

Am 2012-06-01 23:47, schrieb Jeff Morriss:
> To use 'string' fields you'll need to determine the string length first.
>
> 'stringz' fields are strings that you're sure are NULL-terminated and so you should be
> able to use a length of -1 (which means "continue to the NULL terminator") but I'm not
> sure how that can be done in the Lua API (maybe you can just past -1 to the length in
> buffer()?).

Well, as I need the string length in order to progress my read offset into the buffer, I 
now just loop until I find the terminating NULL character, counting loop iterations.

It's not particularly elegant (at least it feels so, remember that I'm still new to 
writing Wireshark dissectors), but I've now used it for a while and it works very well.

If anyone is interested, my current dissector code is at:
http://trac.cafu.de/browser/cafu/trunk/Ca3DE/wireshark-cafu.lua

Best regards,
Carsten



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