Re: [Qemu-devel] [PATCH v5 05/10] qemu-io: allow specifying image as a set of options args

[Eric Blake <eblake@redhat.com>]

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On 02/02/2016 05:57 AM, Daniel P. Berrange wrote:
> Currently qemu-io allows an image filename to be passed on the
> command line, but unless using the JSON format, it does not have
> a way to set any options except the format eg
> 
>  qemu-io https://127.0.0.1/images/centos7.iso
>  qemu-io /home/berrange/demo.qcow2
> 
> This adds a --image-opts arg that indicates that the positional
> filename should be interpreted as a full option string, not
> just a filename.
> 
>  qemu-io --image-opts driver=https,url=https://127.0.0.1/images,sslverify=off
>  qemu-io --image-opts driver=file,filename=/home/berrange/demo.qcow2
> 
> This flag is mutually exclusive with the '-f' flag.

I guess it's easier to enforce the mutual exclusion, than it is to try
and figure out how to make -f work with the --image-opts filename as
long as the two aren't specifying conflicting formats.  Seems okay as
long as it is documented well.

> 
> Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
> ---
>  qemu-io.c | 31 ++++++++++++++++++++++++++++++-
>  1 file changed, 30 insertions(+), 1 deletion(-)
> 

> @@ -515,7 +531,20 @@ int main(int argc, char **argv)
>          flags |= BDRV_O_RDWR;
>      }
>  
> -    if ((argc - optind) == 1) {
> +    if (imageOpts) {
> +        QemuOpts *qopts;
> +        qopts = qemu_opts_parse_noisily(&file_opts, argv[optind], false);

Ouch. If argc == optind (possible if I type 'qemu-io --image-opts'
without a filename), then argv[optind] == NULL, and you end up calling
strncmp(NULL, "id=", 3) inside opts_parse().

Also, I noticed that running 'qemu-io' without arguments puts you into a
shell mode, where you can then open files after the fact via the
open_f() callback function (the 'open' command) - either that function
should that function be given --image-opts support, or use of
--image-opts from the command line should globally affect all subsequent
use of open_f().

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org


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