Re: [Qemu-block] [RFC for-3.1? v1 1/1] qemu-iotests: Don't run the test when user is root

[Eric Blake]

On 11/29/18 4:32 PM, Farhan Ali wrote:
> Test 232 creates image files with read-only permission and
> expects an error message when trying to access the image
> files with read-only and auto-read-only turned off.
>
> Don't run as root user, since root can open files with read/write
> access for read-only files.
>
> Signed-off-by: Farhan Ali <address@hidden>
> ---
>   tests/qemu-iotests/232 | 5 +++++
>   1 file changed, 5 insertions(+)
>
> diff --git a/tests/qemu-iotests/232 b/tests/qemu-iotests/232
> index 0708b8b..40d6692 100755
> --- a/tests/qemu-iotests/232
> +++ b/tests/qemu-iotests/232
> @@ -41,6 +41,11 @@ _supported_fmt generic
>   _supported_proto file
>   _supported_os Linux
>   
> +if [ "$EUID" -eq 0 ]

That's rather fragile. Can we instead do something like:

touch file
chmod a-w file
if [ -w file ]

to probe the actual problem of having sufficient privilege of being able 
to write to a read-only file, without regards to which uids have which 
privileges?

> +then
> +    _notrun "Cannot run this test as root user"
> +fi

Otherwise, it makes sense to me.

If we have a reason to spin 3.1-rc4, we could include this as a 
testsuite robustness fix; but it's not a reason for -rc4 on its own, and 
few enough people are brave enough to run iotests as root that its not a 
showstopper in my mind if this slips to 4.0.

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