Re: [Qemu-devel] [PATCH v2 1/2] blkdebug: Simplify and improve filename generation

[Max Reitz]

On 2014-11-10 at 20:15, Eric Blake wrote:
> On 11/10/2014 09:59 AM, Max Reitz wrote:
> > Instead of actually recreating the options from scratch, just reuse the
> > options given for creating the BDS, which are the configuration file
> > name and additional options. In case there are no additional options we
> > can thus create a plain filename.
> >
> > This obviously results in a different output for qemu-iotest 099 which
> > exactly tests this filename generation. Fix it up as well.
> >
> > Signed-off-by: Max Reitz <address@hidden>
> > ---
> >   block/blkdebug.c           | 98 +++++++++++++---------------------------------
> >   tests/qemu-iotests/099.out |  4 +-
> >   2 files changed, 29 insertions(+), 73 deletions(-)
> >
> >   
> > +    if (!force_json && bs->file->exact_filename[0]) {
> > +        snprintf(bs->exact_filename, sizeof(bs->exact_filename),
> > +                 "blkdebug:%s:%s", qdict_get_try_str(bs->options, "config"),
> If there is no "config" entry, this can pass NULL as a %s counterpart to
> snprintf, which is undefined behavior (works on glibc, but might crash
> elsewhere).

Well, depends on the definition of "works". "blkdebug:(null):foo" isn't 
that great either.

> Everything else looked okay, but I'm afraid I may have given you reason
> to post a v3 and make a kitten cry :(

I do have a reason to post a v3, but the kitten would have to cry only 
if I had to post a v3 because there were no reviews. This way, 
everything is fine, thank you very much for your reviews (on the other 
series as well). :-)

Max