Let's not bother contributors with spurious failures nobody can't
seem to reproduce. There is an issue about that where we're trying
to figure out what's going on: https://github.com/systemd/systemd/issues/10696.
These lines are generally out-of-date, incomplete and unnecessary. With
SPDX and git repository much more accurate and fine grained information
about licensing and authorship is available, hence let's drop the
per-file copyright notice. Of course, removing copyright lines of others
is problematic, hence this commit only removes my own lines and leaves
all others untouched. It might be nicer if sooner or later those could
go away too, making git the only and accurate source of authorship
information.
This part of the copyright blurb stems from the GPL use recommendations:
https://www.gnu.org/licenses/gpl-howto.en.html
The concept appears to originate in times where version control was per
file, instead of per tree, and was a way to glue the files together.
Ultimately, we nowadays don't live in that world anymore, and this
information is entirely useless anyway, as people are very welcome to
copy these files into any projects they like, and they shouldn't have to
change bits that are part of our copyright header for that.
hence, let's just get rid of this old cruft, and shorten our codebase a
bit.
Files which are installed as-is (any .service and other unit files, .conf
files, .policy files, etc), are left as is. My assumption is that SPDX
identifiers are not yet that well known, so it's better to retain the
extended header to avoid any doubt.
I also kept any copyright lines. We can probably remove them, but it'd nice to
obtain explicit acks from all involved authors before doing that.
Without this "meson test" will end up running all tests in the same
cgroup root, and they all will try to manage it. Which usually isn't too
bad, except when they end up clearing up each other's cgroups. This race
is hard to trigger but has caused various CI runs to fail spuriously.
With this change we simply move every test that runs a manager object
into their own private cgroup. Note that we don't clean up the cgroup at
the end, we leave that to the cgroup manager around it.
This fixes races that become visible by test runs throwing out errors
like this:
```
exec-systemcallfilter-failing.service: Passing 0 fds to service
exec-systemcallfilter-failing.service: About to execute: /bin/echo 'This should not be seen'
exec-systemcallfilter-failing.service: Forked /bin/echo as 5693
exec-systemcallfilter-failing.service: Changed dead -> start
exec-systemcallfilter-failing.service: Failed to attach to cgroup /exec-systemcallfilter-failing.service: No such file or directory
Received SIGCHLD from PID 5693 ((echo)).
Child 5693 ((echo)) died (code=exited, status=219/CGROUP)
exec-systemcallfilter-failing.service: Child 5693 belongs to exec-systemcallfilter-failing.service
exec-systemcallfilter-failing.service: Main process exited, code=exited, status=219/CGROUP
exec-systemcallfilter-failing.service: Changed start -> failed
exec-systemcallfilter-failing.service: Unit entered failed state.
exec-systemcallfilter-failing.service: Failed with result 'exit-code'.
exec-systemcallfilter-failing.service: cgroup is empty
Assertion 'service->main_exec_status.status == status_expected' failed at ../src/src/test/test-execute.c:71, function check(). Aborting.
```
BTW, I tracked this race down by using perf:
```
# perf record -e cgroup:cgroup_mkdir,cgroup_rmdir
…
# perf script
```
Thanks a lot @iaguis, @alban for helping me how to use perf for this.
Fixes#5895.
Evgeny Vereshchagin