Re: strace trap tool needed?

[Christoph Höger]

Am Freitag, den 25.07.2008, 09:56 +1000 schrieb Dave Airlie:
>  On Fri, 2008-07-25 at 01:48 +0200, Christoph Höger wrote:
>  > Hi,
>  > 
>  > a little tool came up to my mind today: How about the possibility to
>  > strace a given binary upon execution and write the output to some file?
>  > That could be easy to do (I've already roughly written the code down),
>  > so I am not going to make a package of it.
>  > 
>  > To demonstrate my idea:
>  > if you invoke the script like:
>  > 
>  > trap-strace /usr/bin/less -o /tmp/less.strace
>  > 
>  > after invoking less you cat /tmp/less.strace to see what was going on.
>  > 
>  > Does anyone else need such a tool?
>  > If so, what package could collect it, and what constraints (language,
>  > i/o, etc.) should it comply with?
>  > 
>  
>  any reason
>  
>  strace -o /tmp/less.strace /usr/bin/less
>  
>  won't work?
>  
>  Or did I miss something?
>  
>  Dave.
>   
well, strace starts the process itself, that is not always usefull.
Consider complex scripts or applications that fork-exec alot around.
Sometimes you (or, at least I ;) ) just do not want the complete strace
with fork() or clone() but just the output of one particular binary in
the chain. My tool would set up a trap which invokes strace when the
binary is executed (basically you could do that by replacing the binary
with a script wrapper).