Re: [Valgrind-users] using valgrind to debug uninitialized mem in servern

[Matthias A. <gu...@un...>]

El día jueves, febrero 04, 2021 a las 09:48:23a. m. +0000, Tom Hughes escribió:

> On 04/02/2021 09:26, Matthias Apitz wrote:
> 
> > At the moment we use the following "trick": the librarian runs in
> > parallel to the client on the desktop a second window with a "tail -f ..."
> > on valgrinds log file (STDOUT) and the full screen is recorded with
> > Microsoft teams functionality. So we can use the timestamps in the log
> > to go to the replay of the recording and can see what the user did
> > exactly, which data was entered and which button pressed etc.
> > 
> > Are there other ideas to bring together the valgrind log and the usage
> > of the application?
> 
> You could instrument the request processing logic to log details
> of the request if any errors are detected while processing it, so
> something like:
> 
>   #include "valgrind/valgrind.h"
> 
>   return_type process_request(...)
>   {
>     int errors = VALGRIND_COUNT_ERRORS;
> 
>     // process request as normal
> 
>     if (VALGRIND_COUNT_ERRORS > errors)
>     {
>       VALGRIND_PRINTF("Saw errors processing request %s", request_name);
>     }
>   }
> 
> Obviously you can change it to log whatever details you want.

Thanks, this looks like a good plan!

The above are macros, are there additional shared libs to link with our
process?

> 
> The only issue might be that if the code is multithreaded and can
> process multiple requests in parallel then you won't know which
> thread the errors came from.

No, they're singlethreaded. A master daemon forks for any connecting
client a new server proc.

	matthias

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Matthias Apitz, ✉ gu...@un..., http://www.unixarea.de/ +49-176-38902045
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