Re: QEMU policy for real file tests

["Daniel P. Berrangé" <berrange@redhat.com>]

On Thu, Sep 17, 2020 at 10:26:36AM +0100, Alex Bennée wrote:
> 
> Christian Schoenebeck <qemu_oss@crudebyte.com> writes:
> 
> > Hi,
> >
> > is there a QEMU policy for test cases that create/write/read/delete real files 
> > and directories? E.g. should they be situated at a certain location and is any 
> > measure of sandboxing required?
> 
> I don't think we have a hard and fast policy. It also depends on what
> you are doing the test in - but ideally you should use a secure mktempd
> (that can't clash) and clean-up after you are finished. This is a bit
> easier in python than shell I think.

mktempd will end up on /tmp usually which can be tmpfs and size limited,
so be mindful of the size of files you create. Don't assume you can
create multi-GB sized files !  Creating a temp dir underneath the build
dir (effectively CWD of the test) is a reasonable alternative.

> For example iotests end up in $BUILD_DIR/scratch (driven by TEST_DIR
> being set somewhere) whereas the gdb stub tests use socket_dir =
> TemporaryDirectory("qemu-gdbstub") which get auto-cleaned when it
> finishes.

Regards,
Daniel
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