Invoking %systemd_tmpfiles (in %post) without any arguments, while
possible, will cause systemd-tmpfiles to process the entire system
configuration, rather than just the newly installed configuration
files. In https://github.com/systemd/systemd/pull/12048, it was
established that processing everything constitutes unusual practice,
and should be flagged as a mistake at build time.
Furthermore, invoking %systemd_post without any arguments will cause
the underlying `systemctl preset` to outright return an error ("Too
few arguments") when run. This can be flagged during build time in
the same manner.
As I have found no ways to successfully nest %if clauses inside a
macro[1], I am helping myself by reusing the recursive variable
expansion technique pioneered in [2].
Now, when %systemd_post or %systemd_tmpfiles is incorrectly used,
rpm gives accurate line number reporting, too:
error: This macro requires some arguments
error: line 11: %{systemd_post}
error: This macro requires two arguments
error: line 13: %{tmpfiles_create_package meh more more}
[1] what has been tried: %{expand:%%if "%#" == 0 \\\
%%{error:you have given me %# args} \\\
%%endif}
[2] http://git.savannah.gnu.org/cgit/automake.git/commit/?id=e0bd4af16da88e4c2c61bde42675660eff7dff51
Logically, this is better, because we're describing a subset of possible
return values. Visually this also looks quite good because groff renders
refsect2 much less prominently.
Also rewrap things, add <constant> in various places, fix some typos.
No other changes, just some reshuffling and adding of section headers
(well, admittedly, I changed some "see above" and "see below" in the
text to match the new order.)
As general principle, we generally check command line args first, the
enviroment second, and external configuration and system state only later.
In case of the invocation ID, checking the keyring before the environment
was implemented as a poor-man's security measure. But this is not really
useful, since we're moving within the same security boundary. So let's just
do the expected thing, and check environment first.
Prompted by https://github.com/systemd/systemd/pull/11991#issuecomment-474647652.
This makes two changes:
1. Instead of resetting the configured service TTY each time after a
process exited, let's do so only when the service goes back to "dead"
state. This should be preferable in case the started processes leave
background child processes around that still reference the TTY.
2. chmod() and chown() the TTY at the same time. This should make it
safe to run "systemd-run -p DynamicUser=1 -p StandardInput=tty -p
TTYPath=/dev/tty8 /bin/bash" without leaving a TTY owned by a dynamic
user around.
Jan Engelhardt
Yu Watanabe
Zbigniew Jędrzejewski-Szmek
Lennart Poettering