Re: [Qemu-devel] [RFC PATCH 2/2] qga: add --getenv option to get env. vars from fw_cfg

[Daniel P. Berrange]

On Tue, Feb 24, 2015 at 02:43:07PM -0500, Gabriel L. Somlo wrote:
> The new "-g" (or "--getenv") command line option causes qemu-ga to extract
> and parse the "etc/guestenv" blob from fw_cfg, and return the value of
> the requested key (if available) on stdout.
> 
> Warnings and error messages are printed to stderr, and only the actual
> value portion of a "key=value" string matching the "--getenv key" argument
> will be printed to stdout. Strings are searched in reverse order to
> implement a sort of "last dupe wins" policy -- but I expect to refine
> things quite a bit after receiving some feedback.
> 
> I've added a flag to qemu-ga instead of creating a completely separate
> binary, but I don't feel strongly about keeping it that way. I just need
> something that would end up tightly integrated with the "qemu guest tools"
> package...

It should really be a separate binary. Overloading multiple functions in
one binary makes it very hard to write a security policy to confine what
the binary can do, as you can't get the kernel to apply different policies
based on what CLI flag was passed.

Regards,
Daniel
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