[Pkg-utopia-maintainers] Bug#881342: dbus: apt-get install hangs when DBUS is setup, on a Minimal system

[Simon McVittie]

On Fri, 10 Nov 2017 at 20:28:55 +0530, Veek M wrote:
> Nov 10 19:52:01 deathstar dbus-daemon[17738]: Failed to start message bus: Could not get UID and GID for username "messagebus"

Your username database seems to be missing the dbus-daemon's required system
user. What do these commands output?

    cat /etc/nsswitch.conf
    getent passwd messagebus
    getent group messagebus
    ls -l /usr/lib/dbus-1.0/dbus-daemon-launch-helper

dbus.postinst invokes adduser(8) to create that user before
it starts the dbus-daemon. If you are using LDAP, NIS or other
remote/centralized/unusual sources of usernames and groups, you will
likely need to make sure the messagebus user is available on the local
system (even before networking comes up) to avoid circular dependencies
during boot.

Trying to run

    bash -x /var/lib/dpkg/info/dbus.postinst configure 1.10.22-0+deb9u1

might also provide useful information.

Trying to run

    adduser --system --home /nonexistent --no-create-home --disabled-password --group messagebus

might also be interesting; it might work around the issue, or it might
produce output that indicates what is wrong.

> Nov 10 19:52:26 deathstar systemd[1]: dbus.service: Main process exited, code=exited, status=1/FAILURE
> Nov 10 19:52:26 deathstar systemd[1]: dbus.service: Unit entered failed state.
> Nov 10 19:52:26 deathstar systemd[1]: dbus.service: Failed with result 'exit-code'.

If the messagebus user is not available, then this (and the rest of
the failures you quoted) is expected. The system dbus-daemon runs as a
dedicated system user (messagebus) for privilege-separation, and will
not work without it. The only way it could work without that user would
be to run as root, which is a significant security risk.

> Nov 10 19:51:02 deathstar systemd-udevd[233]: specified user 'usbmux' unknown

udev also complains about a missing user, although unlike for dbus, this
isn't immediately fatal, because udev doesn't immediately need to run a
daemon as that user.

Regards,
    smcv