[apparmor] Bug#883584: A reload deletes /etc/apparmor.d/cache/CACHEDIR.TAG

[John Johansen]

On 01/08/2018 04:28 AM, Simon McVittie wrote:
> On Mon, 08 Jan 2018 at 02:21:26 -0800, John Johansen wrote:
>> On 01/07/2018 07:26 AM, intrigeri wrote:
>>>>> Dear upstream/parser developers, would it feel crazy to modify
>>>>> clear_cache_cb to ignore the passed file if its basename is
>>>>> CACHEDIR.TAG?
>>
>> Well that isn't reason [not?] to add another file type that will be skipped. It
>> should be a fairly easy modification. In fact the cache isn't necessarily
>> the only dir we might want to skip so
>>
>>   SKIPDIR.TAG
>> or
>>   IGNOREDIR.TAG
>>
>> might even be better to have
> 
> For context, CACHEDIR.TAG is not a new thing that intrigeri invented
> recently: it's a pre-existing standard for marking cache directories
> to be skipped by backup software and similar consumers. For example,
> VLC, ccache and fontconfig all create it in their cache directories,
> and GNU tar, Borg Backup and Obnam have an --exclude-caches option
> that avoids backing up the tagged directories.  More information:
> http://www.brynosaurus.com/cachedir/
> 
> At the moment it's mostly seen in desktop applications (creating it)
> and in backup/sync software (detecting it), but there's no particular
> reason for system components not to participate in that mechanism too.
> 
> If AppArmor created this tag itself, that might be even better, but at
> the moment intrigeri is only asking for it to not be deleted, so that a
> sysadmin or OS vendor can create it and have it persist.
> 
ah, thanks. I'll see if I can't get a patch together today