Re: [Qemu-stable] [PATCH 1/2] qemu-img: Fix dd with skip= and count=

[Eric Blake]

On 08/15/2018 09:03 PM, Max Reitz wrote:

> > @@ -4559,19 +4559,23 @@ static int img_dd(int argc, char **argv)
> >           goto out;
> >       }
> >
> > +    /* Overflow means the specified offset is beyond input image's size */
> > +    if (dd.flags & C_SKIP && (in.offset > INT64_MAX / in.bsz ||
> > +                              size < in.bsz * in.offset)) {
> > +        size = 0;
> > +        error_report("%s: cannot skip to specified offset", in.filename);
>
> in_pos should be initialized as well (to "size", I suppose), or my gcc
> will continue to complain. :-)

Serves me right for compiling with -g instead of -O2 (gcc only does that 
warning on optimized builds, for some weird reason).  Will fix in v2.


> > +++ b/tests/qemu-iotests/160
> > @@ -44,6 +44,7 @@ _supported_os Linux
> >   TEST_SKIP_BLOCKS="1 2 30 30K"
> >
> >   for skip in $TEST_SKIP_BLOCKS; do
> > +  for count in '' 'count=1 '; do
>
> Ah, so this is why we indent everything by four spaces!  So you can
> squeeze in three more block headers without having to re-indent
> everything.  I finally see. O:-)

I'm seriously thinking of reindenting things in this and the next patch, 
rather than my initial quick-and-dirty "squeeze it in".  'git diff -w' 
is not that hard to use, after all.

> (Not sure why you put a space after the 'count=1', though, but OK)

For this line:

+    echo "== Converting the image with dd with ${count}skip=$skip =="

so that when $count is empty, the .out file doesn't end up with a double 
space.  Okay, I do have some sense of output aesthetics, even if my 
re-indentation skills are lacking ;=)

--
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org