Bug#1016064: rpcbind: rpcbind.service fails with "cannot get uid of '_rpc': Success"

[Martin Pitt]

Package: rpcbind
Version: 1.2.6-4
Severity: serious

A fresh installation of rpcbind fails to start the service:

systemd[1]: Starting RPC bind portmap service...
rpcbind[314]: cannot get uid of '_rpc': Success
systemd[1]: rpcbind.service: Main process exited, code=exited, status=1/FAILURE
systemd[1]: rpcbind.service: Failed with result 'exit-code'.
systemd[1]: Failed to start RPC bind portmap service.

That's because the `_rpc` user does not exist. Upgrading from an earlier image
(with 1.2.6-3) works because earlier versions created it:

# id _rpc
uid=108(_rpc) gid=65534(nogroup) groups=65534(nogroup)

Release -4 said "Remove obsolete debian/postinst file", and most of it may be
obsolete, but not this bit:

if [ "$1" = configure ] ; then
# run daemon as non-root (see #852066)
adduser --force-badname --system --quiet --home /run/rpcbind --no-create-home _rpc

Please put this back. Or better yet, use systemd's User=, DynamicUser=, and
RuntimeDirectory= options to contain all of the setup in the unit.

Thanks!

Martin