Bug#839686: forked-daapd: does not recreate stuff in /var/cache after deletion

[Balint Reczey]

Control: notfound -1 24.1-1+b1

Hi Dominik,

On Mon, 03 Oct 2016 23:23:26 +0200 Dominik George <nik at naturalnet.de> wrote:
> Package: forked-daapd
> Version: 24.1-1+b1
> Severity: serious
> Justification: Policy 9.1.1
> 
> After deleting /var/cache/forked-daapd, forked-daapd cannot start up
> again because it fails to open the database.
> 
> forked-daapd seems to require its data files there, while the FHS
> unmistakably states:
> 
> "Unlike /var/spool, the cached files can be deleted without data loss.
> The data must remain valid between invocations of the application and
> rebooting the system.
> 
> Files located under /var/cache may be expired in an application specific
> manner, by the system administrator, or both. The application must
> always be able to recover from manual deletion of these files (generally
> because of a disk space shortage). No other requirements are made on the
> data format of the cache directories."

I have tested unstable's forked-daapd and if I remove cache files they
get recreated but the directory structure is not.

IMO it is unreasonable to think that removing the whole
/var/cache/forked-daapd directory can be deleted and is expected to be
recreated because many services drop root privileges thus can't create
dirs in /var/cache:

total 64
drwxr-xr-x 16 root  root 4096 Oct  6 20:56 .
drwxr-xr-x 11 root  root 4096 Sep  5 23:27 ..
drwxr-xr-x  3 root  root 4096 Sep  7 14:08 app-info
drwxr-xr-x  3 root  root 4096 Oct  6 20:56 apt
drwxr-xr-x  2 root  root 4096 Sep  7 14:08 cracklib
drwxr-xr-x  2 root  root 4096 Oct  5 09:25 debconf
drwxr-xr-x  2 root  root 4096 Sep  5 23:28 dictionaries-common
drwxr-xr-x  2 root  root 4096 Sep  8 20:40 fontconfig
drwxr-xr-x  2 root  root 4096 Feb 22  2016 fonts
drwxr-xr-x  2 daapd root 4096 Oct  6 21:01 forked-daapd
drwxr-xr-x  2 root  root 4096 Aug 31 08:28 gdm
drwx------  2 root  root 4096 Oct  6 20:56 ldconfig
drwx--x--x  3 root  root 4096 Sep  7 15:39 lightdm
drwxr-sr-x 37 man   root 4096 Oct  6 21:00 man
drwxr-xr-x  3 root  root 4096 Sep  7 14:08 PackageKit
drwxr-xr-x  2 root  root 4096 Aug 15 11:17 realmd

In my interpretation of the FHS the _files_ can be removed and are
expected to be recreated, while _directory structures_ need to be kept
for applications to operate.

Cheers,
Balint