Re: [Qemu-devel] [PATCH for-2.9 2/2] block/curl: Check protocol prefix

[Eric Blake <eblake@redhat.com>]

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On 03/31/2017 07:04 AM, Max Reitz wrote:
> If the user has explicitly specified a block driver and thus a protocol,
> we have to make sure the URL's protocol prefix matches. Otherwise the
> latter will silently override the former which might catch some users by
> surprise.
> 
> Signed-off-by: Max Reitz <mreitz@redhat.com>
> ---
>  block/curl.c | 10 ++++++++++
>  1 file changed, 10 insertions(+)
> 

It feels a little bit dirty that we are parsing the URL rather than
having a distinct discriminator, but I'm okay with the approach (with a
distinct discriminator, we would have to reconstruct a URL from the
discriminator + the rest of the server/path information, and that's more
work to libvirt to split a URL into the distinct JSON fields just to
have qemu rebuild a URL).

> +    if (!strstart(file, bs->drv->protocol_name, &protocol_delimiter) ||
> +        !strstart(protocol_delimiter, "://", NULL))
> +    {
> +        error_setg(errp, "%s curl driver cannot handle the URL '%s' (does not "
> +                   "start with '%s://')", bs->drv->protocol_name, file,
> +                   bs->drv->protocol_name);

Perhaps splitting the message with an error_append_hint() for the
parenthetical half would also be appropriate, but the line is not too
terribly long so I won't insist on a respin.

Reviewed-by: Eric Blake <eblake@redhat.com>

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


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