TEST-26-SYSTEMCTL is racy as we call systemctl is-active immediately
after systemctl kill. Let's implement --wait for systemctl kill and
use it in TEST-26-SYSTEMCTL to avoid the race.
This allows accompanying a signal with a value (as supported for Linux
Realtime signals). This is particularly useful as it allows us to do
stuff like this:
systemctl kill --kill-whom=main --kill-value=0x300 systemd-journald
In order to ask journald to flush its allocation caches and compact
memory.
getopt allows non-ambiguous abbreviations, so backwards-compat is maintained, and
people can use --kill-who (or even shorter abbreviations). English is flexible,
so in common speach people would use both forms, even if "whom" is technically
more correct. The advantage of using the longer form in the code is that we
effectively allow both forms, so we stop punishing people who DTGCT¹, but still
allow people to use the spoken form if they prefer.
1. Do the gramatically correct thing
Let's clean up our function naming a bit, and always name the
verb_xyz(), where the xyz maps to the command line verb as closely as
possible.
No actual code changes, just an attempt to make the systemctl sources a
bit more systematic, and less surprising.
When fuzzing, the following happens:
- we parse 'data' and produce an argv array,
- one of the items in argv is assigned to arg_host,
- the argv array is subsequently freed by strv_freep(), and arg_host has a dangling symlink.
In normal use, argv is static, so arg_host can never become a dangling pointer.
In fuzz-systemctl-parse-argv, if we repeatedly parse the same array, we
have some dangling pointers while we're in the middle of parsing. If we parse
the same array a second time, at the end all the dangling pointers will have been
replaced again. But for a short time, if parsing one of the arguments uses another
argument, we would use a dangling pointer.
Such a case occurs when we have --host=… --boot-loader-entry=help. The latter calls
acquire_bus() which uses arg_host.
I'm not particularly happy with making the code more complicated just for
fuzzing, but I think it's better to resolve this, even if the issue cannot
occur in normal invocations, than to deal with fuzzer reports.
Should fix https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=31714.
This is just some refactoring: shifting around of code, not change in
codeflow.
This splits up the way too huge systemctl.c in multiple more easily
digestable files. It roughly follows the rule that each family of verbs
gets its own .c/.h file pair, and so do all the compat executable names
we support. Plus three extra files for sysv compat (which existed before
already, but I renamed slightly, to get the systemctl- prefix lik
everything else), a -util file with generic stuff everything uses, and a
-logind file with everything that talks directly to logind instead of
PID1.
systemctl is still a bit too complex for my taste, but I think this way
itc omes in a more digestable bits at least.
No change of behaviour, just reshuffling of some code.
Lennart Poettering
Daan De Meyer
Zbigniew Jędrzejewski-Szmek
Yu Watanabe