File /etc/66/service/dbus has this:
[main]
@type = longrun
@version = 0.0.6
@description = "dbus system daemon"
@user = ( root dbus )
@maxdeath = 3
@notify = 4
@options = ( log env )
@timeout-up = 3000
[start]
@build = auto
@execute = (
execl-toc -S ${socket_name} -m 0755
foreground { dbus-uuidgen --ensure=/etc/machine-id }
execl-cmdline -s { dbus-daemon ${cmd_args} }
)
[stop]
@build = auto
@execute = ( s6-rmrf ${socket_name} )
[environment]
cmd_args=!--system --print-pid=4 --nofork --nopidfile
socket_name=!/run/dbus/system_bus_socket
This line is interesting:
foreground { dbus-uuidgen --ensure=/etc/machine-id }
From man dbus-uuidgen:
BTW, I just cat-ed /etc/machine-id and /var/lib/dbus/machine-id and they are different. Running lsattr on them reveals they both have only 'e' flag set.