content interface, DENIED mounting $SNAP/mydir

[Simon Fels]

On 03.03.2017 01:06, Michi Henning wrote:
> 
>> On 3 Mar 2017, at 4:33 , knitzsche <kyle.nitzsche at canonical.com
>> <mailto:kyle.nitzsche at canonical.com>> wrote:
>>
>> Hi,
>>
>> I am trying to use the wifi-ap content sharing interface.
>>
>> It is DENIED (see below) when I try to use a $SNAP directory.
>>
>> It works when I instead use $SNAP_DATA directory for the content
>> sharing. But, I have to create that directory at run time: I can't
>> figure out so far how to create (from snapcraft.yaml) an empty dir in
>> $SNAP_COMMON or $SNAP_DATA at install time. (Knowing this would solve
>> my problem.)
> 
> 
> We do this to create a directory:
> 
> install: |
>       # Make sure we have a mount point for ubuntu-app-platform
>       mkdir -p $SNAPCRAFT_PART_INSTALL/ubuntu-app-platform

That doesn't help much here as we're bind-mounting read/write data and
that seems to be not possible to go into somewhere below $SNAP.

I fear the only answer to this problem are interface hooks which would
allow us to create the relevant directory before the bind-mount happens
inside $SNAP_DATA.

regards,
Simon