Re: [Qemu-devel] [PATCH 4/4][RFC] Add logic to QEMU to read command line options from qcow2 images

["Carlos A. M. dos Santos" <unixmania@gmail.com>]

On 8/10/07, dmc <dmc@filteredperception.org> wrote:
> Brian Wheeler wrote:
> > On Thu, 2007-08-09 at 15:32 -0500, Anthony Liguori wrote:
> >> Avi Kivity wrote:
> >>> Anthony Liguori wrote:
> >>>> If you're looking for a low-end solution, another possibility would
> >>>> be having a "new" file format which consisted of:
> >>>>
> >>>> #!/path/to/qemu [<args> ...] <nl>
> >>>> <standard disk image>
> >>>>
> >>>> And then make the appropriate changes to QEMU such that it can skip
> >>>> the first line in a disk image file.  This has a few nice side
> >>>> effects.  The disk image is directly executable and it makes it very
> >>>> clear to the user that they have to trust the disk image.  The other
> >>>> nice thing is that it would work with file formats other than qcow2.
> >>> Well, it would be nice to align the disk image to a sector boundary
> >>> (or, better, a page boundary).  But yes, a very good idea.
> >> That has the very nice side effect of allowing you to edit the command
> >> line with a text editor provided you don't cross the sector boundary.
> >> Filling with spaces would be pretty nice.
> >>
> >
> >
> > Its a bad idea.  Either have a line terminated file, or a pure binary
> > file, but don't mix them.  Besides firing up an editor to modify it
> > being a royal pain, mystery breakages will occur when someone has their
> > editor set to "insert mode" (which is the default) vs "overwrite mode"
> > and doesn't notice those extra spaces moving beyond the 512-byte mark.
>
> how about xml appended to image file, and size of xml appended to that?
>   And a tool to easily extract/replace the xml.  Just my $0.02...

Keep it *simple*, please!

-- 
Carlos A. M. dos Santos