[PATCH] Improve Windows Minidump File Specification

[Richard Fearn]

Hi,

> It seems like you are asking for a similar piece of functionality as
> Richard(cc:d) did:
> http://mail.openjdk.java.net/pipermail/hotspot-dev/2013-July/010390.html

Yes, sounds very similar...

> Since Windows is the only platform where we can decide on the file name of
> the mdmp/core file it would be good if we could make this into a
> platform-independent flag -XX:CrashFileDirectory or something to that
> effect.
>
> Then we could change the code to create the hs_err_pid<num>.log in that
> directory

The location of that file (the fatal error log) can already be
specified by -XX:ErrorFile, though.

> and
> * change the Windows code to create the mdmp in that directory
> * change the *nix code to chdir(2) to the target directory before calling
> abort(3)

As an experiment, I added a -XX:CoreDumpDirectory option, and did the
chdir quite early - before the fatal error log was written. This meant
the fatal error log went into the CoreDumpDirectory, too, which I
wasn't happy with, given the option name. However, if the option was
called CrashFileDirectory, it would make more sense if the fatal error
log were written into that directory as well.

I moved the chdir later, but hit another problem: the fatal error log
gives the current directory as a suggestion as to where the core dump
can be found. If the current directory is changed later on, that will
be incorrect. A nice side effect of allowing the fatal error log to go
into the CrashFileDirectory would be that the current directory
*could* be changed earlier (unless there's something else that would
be affected by this, that I haven't spotted).

I'd be happy to provide patches for the changes I've made, though I
agree that it might be good to have a unified approach to this.

Rich

-- 
Richard Fearn
richardfearn at gmail.com