bus: fake client side creds in the proxy to the caller's creds
bus: make gcc shut up
bus: fix hello ioctl buffer size calculation
util: unify SO_PEERCRED/SO_PEERSEC invocations

Introduce new call getpeercred() which internally just uses SO_PEERCRED
but checks if the returned data is actually useful due to namespace
quirks.
bus: only accept kdbus creds if they are valid

This allows userspace to fake kdbus creds via struct ucred in the proxy,
without making the recieving side choke on the missing fields of the
kdbus struct, more precisel pid_starttime and tid
util: don't accept an empty peer label as valid
log: log_error() and friends add a newline after each line anyway, so avoid including it in the log strings
busctl: show service/session a name belongs to in the list of names

Also, don't show machine name by default as this might cause timeouts on
non-responding peers.
bus: fix return message if StartServiceByName() in the driver fails due
to non-existing service
bus: properly shift cgroup data returned from kdbus by the container's root before parsing
man,units: tmpfiles.d(5) cleanup

Condition for /lib (necessary for split /usr) was missing from the unit.

Some changes which were done in tmpfiles.d(5) were not carried over to
systemd-tmpfiles(1).

Also use markup where possible.
tmpfiles: introduce the concept of unsafe operations

Various operations done by systemd-tmpfiles may only be safely done at
boot (e.g. removal of X lockfiles in /tmp, creation of /run/nologin).
Other operations may be done at any point in time (e.g. setting the
ownership on /{run,var}/log/journal). This distinction is largely
orthogonal to the type of operation.

A new switch --unsafe is added, and operations which should only be
executed during bootup are marked with an exclamation mark in the
configuration files. systemd-tmpfiles.service is modified to use this
switch, and guards are added so it is hard to re-start it by mistake.

If we install a new version of systemd, we actually want to enforce
some changes to tmpfiles configuration immediately. This should now be
possible to do safely, so distribution packages can be modified to
execute the "safe" subset at package installation time.

/run/nologin creation is split out into a separate service, to make it
easy to override.

https://bugzilla.redhat.com/show_bug.cgi?id=1043212
https://bugzilla.redhat.com/show_bug.cgi?id=1045849
sleep-config: fix useless check for swapfile type

Since 0c6f1f4ea49 the check was useless, because the kernel will
ever only write "partition" or "file" there.

OTOH, it is possible that "\\040(deleted)" (escaped " (deleted)")
will be added for removed files. This should not happen, so add
a warning to detect those cases.
unit: include peer identity in description of per-connection socket-activated services
shared: fix getpeername_pretty() for AF_UNIX sockets
bus: be a bit more verbose when debug mode is on
bus: also write debug logs about messages we send
bus: set cookie_reply and update kdbus.h
bus: update kdbus.h