Sometimes we have to connect to the system manager directly (early boot,
initrd, late boot, ...), sometimes through the system bus (unprivileged,
remote, logind, ...). Instead of guessing in advance, which kind of
connection we require (and sometimes guessing incorrectly), let's make
sure each time we need bus connection we request the right bus
explicitly.
This way, we set up exactly the bus connections require, never guess
incorrectly, and do so only immediately when necessary.
As effect this reworks avoid_bus() into install_client_side(), since
that's all it determines now: whether to install unit files client-side
or server-side (i.e. in PID 1).
In sd-bus, the sd_bus_open_xyz() family of calls allocates a new bus,
while sd_bus_default_xyz() family tries to reuse the thread's default
bus. bus_open_transport() sometimes internally uses the former,
sometimes the latter family, but suggests it only calls the former via
its name. Hence, let's avoid this confusion, and generically rename the
call to bus_connect_transport().
Similar for all related calls.
And while we are at it, also change cgls + cgtop to do direct systemd
connections where possible, since all they do is talk to systemd itself.
Previously, we'd allocate it sometimes from the heap, but otherwise let
it point directly int argv[]. Let's clean this up, so that we know
exactly how to release its resources, and do so at the end.
logind sends out wall messages now, let's remove this from the systemctl
client side hence. If people build systemd without logind support they
won't get wall messages now, but that's OK.
This sounds like the better place to expose this than in "systemd-notify
--booted".
Also document the so far undocumented "unknown" state the command might
return. And rearrange the table of states documented to be more like the
one for "is-running".
Also, don't document the precise exit code of this function, just say
errors are reported != 0 or > 0...
This also allows us to drop build.h from a ton of files, hence do so.
Since we touched the #includes of those files, let's order them properly
according to CODING_STYLE.
Let's underline the header line of the table shown by cgtop, how it is
customary for tables. In order to do this, let's introduce new ANSI
underline macros, and clean up the existing ones as side effect.
If code enqueues a message on one of the default busses, but doesn't
sync on it, and immediately drops the reference to the bus again, it
will stay queued and consume memory. Intrdouce a new call
sd_bus_default_flush_close() that can be invoked at the end of programs
(or threads) and flushes out all unsent messages on any of the default
busses.
When a systemd service running in a container exits with a non-zero
code, it can be useful to terminate the container immediately and get
the exit code back to the host, when systemd-nspawn returns. This was
not possible to do. This patch adds the following to make it possible:
- Add a read-only "ExitCode" property on PID 1's "Manager" bus object.
By default, it is 0 so the behaviour stays the same as previously.
- Add a method "SetExitCode" on the same object. The method fails when
called on baremetal: it is only allowed in containers or in user
session.
- Add support in systemctl to call "systemctl exit 42". It reuses the
existing code for user session.
- Add exit.target and systemd-exit.service to the system instance.
- Change main() to actually call systemd-shutdown to exit() with the
correct value.
- Add verb 'exit' in systemd-shutdown with parameter --exit-code
- Update systemctl manpage.
I used the following to test it:
| $ sudo rkt --debug --insecure-skip-verify run \
| --mds-register=false --local docker://busybox \
| --exec=/bin/chroot -- /proc/1/root \
| systemctl --force exit 42
| ...
| Container rkt-895a0cba-5c66-4fa5-831c-e3f8ddc5810d failed with error code 42.
| $ echo $?
| 42
Fixes https://github.com/systemd/systemd/issues/1290
