This code is executed before we parse command line/configuration
parameters, hence let's not use arg_system to figure our how to clean up
things, but instead PID == 1. Let's move that check inside of the
function, to make things a bit more robust abstract from the outside.
Also, let's add a log message about this, that was so far missing.
Let's place them in initialize_runtime(), where they appear to fit best.
Effectively this is just a move a little bit down, swapping places with
log_execution_mode(), which should require neither call to be done
first.
Note that changes the conditionalization a bit for these calls, from
(PID == 1) to (arg_system && arg_action == ACTION_RUN). At this point this is pretty much the same
however, as we don't allow PID 1 without ACTION_RUN and without
arg_system set, safety_checks() ensures that.
It's part of finalizing our runtime parameters, hence let's move this
into load_configuration() after we loaded everything else. This is safe,
since we don't use it between the location where it was and where we
place it now yet.
This just sets up some variables the loaded configuration will then
modify. Let's invoke it hence right before loading the configuration.
This moves the initialization just a tiny bit later, but that shouldn't
matter, since we never access it in-between.
Let's make sure that if we are PID 1 we are invoked in ACTION_RUN mode,
and in arg_system mode, as well as the opposite.
Everything else is untested and probably not worth supporting hence
let's bail out early if people try anyway.
Let's shorten main() a bit, and split out everything that loads our
configuration and runtime parameters into a function of its own.
No changes in behaviour.
This makes things a bit easier to read I think, and also makes sure we
always use the _unlikely_ wrapper around it, which so far we used
sometimes and other times we didn't. Let's clean that up.
Dec 14 14:10:54 krowka systemd[1]: System is tainted: overflowgid-not-65534
-- Subject: The system is configured in a way that might cause problems
-- Defined-By: systemd
-- Support: https://lists.freedesktop.org/mailman/listinfo/systemd-devel
--
-- The following "tags" are possible:
-- - "split-usr" — /usr is a separate file system and was not mounted when systemd
-- was booted
-- - "cgroups-missing" — the kernel was compiled without cgroup support or access
-- to expected interface files is resticted
-- - "var-run-bad" — /var/run is not a symlink to /run
-- - "overflowuid-not-65534" — the kernel user ID used for "unknown" users (with
-- NFS or user namespaces) is not 65534
-- - "overflowgid-not-65534" — the kernel group ID used for "unknown" users (with
-- NFS or user namespaces) is not 65534
-- Current system is tagged as overflowgid-not-65534.
We have a check and warning at compile time. The user cannot do anything about
this at runtime, and all other taints are about checks that happen at runtime
and are specific to that system (and at least potentially correctable).
(The logic in the compilation-time check was updated to treat "nogroup" as OK,
but not the runtime check. But I think it's better to remove the runtime check
for this altogether, so this becomes moot.)
Followup to previous commit. Suggested by @poettering.
Reindented the `verbs[]` tables to match the apparent previous
whitespace rules (indent to one flag, allow multiple flags to overflow?).
A lot of code references the `running_in_chroot()` function; while
I didn't dig I'm pretty certain this arose to deal with situations
like RPM package builds in `mock` - there we don't want the `%post`s
to `systemctl start` for example.
And actually this exact same use case arises for
[rpm-ostree](https://github.com/projectatomic/rpm-ostree/)
where we implement offline upgrades by default; the `%post`s are
always run in a new chroot using [bwrap](https://github.com/projectatomic/bubblewrap).
And here's the problem: bwrap creates proper mount roots, so it
passes `running_in_chroot()`, and then if a script tries to do
`systemctl start` we get:
`System has not been booted with systemd as init system (PID 1)`
but that's an *error*, unlike the `running_in_chroot()` case where we ignore.
Further complicating things is there are real world RPM packages
like `glusterfs` which end up invoking `systemctl start`.
A while ago, the `SYSTEMD_IGNORE_CHROOT` environment variable was
added for the inverse case of running in a chroot, but still wanting
to use systemd as PID 1 (presumably some broken initramfs setups?).
Let's introduce a `SYSTEMD_OFFLINE` environment variable for cases like
mock/rpm-ostree so we can force on the "ignore everything except preset" logic.
This way we'll still not start services even if mock switches to use nspawn or
bwrap or something else that isn't a chroot.
We also cleanly supercede the `SYSTEMD_IGNORE_CHROOT=1` which is now spelled
`SYSTEMD_OFFLINE=0`. (Suggested by @poettering)
Also I made things slightly nicer here and we now print the ignored operation.
This is useful to debug things, but also to hook up external post-up
scripts with resolved.
Eventually this code might be useful to implement a
resolvconf(8)-compatible interface for compatibility purposes. Since the
semantics don't map entirely cleanly as first step we add a native
interface for pushing DNS configuration into resolved, that exposes the
correct semantics, before adding any compatibility interface.
See: #7202
memset() is weird anyway, since it expects an "int" as second parameter,
which it then uses as a byte, i.e. as uint8_t or something like that.
But by passing -1 to it, things get particularly weird, as that relies
on sign expansion to do the right thing.
In similar fashion to the previous change, sync() operations can stall
endlessly if cache is unable to be written out. In order to avoid an
unbounded hang, the sync takes place within a child process. Every 10
seconds (SYNC_TIMEOUT_USEC), the value of /proc/meminfo "Dirty" is checked
to verify it is smaller than the last iteration. If the sync is not making
progress for 3 successive iterations (SYNC_PROGRESS_ATTEMPTS), a SIGKILL is
sent to the sync process and the shutdown continues.
Remount, and subsequent umount, attempts can hang for inaccessible network
based mount points. This can leave a system in a hard hang state that
requires a hard reset in order to recover. This change moves the remount,
and umount attempts into separate child processes. The remount and umount
operations will block for up to 90 seconds (DEFAULT_TIMEOUT_USEC). Should
those waits fail, the parent will issue a SIGKILL to the child and continue
with the shutdown efforts.
In addition, instead of only reporting some additional errors on the final
attempt, failures are reported as they occur.
Lennart Poettering
Yu Watanabe
Zbigniew Jędrzejewski-Szmek
Colin Walters
Kyle Walker
Cong Wang