Before this patch, there was no way to request all running user instances for
reexecuting. However this can be useful especially during package updates
otherwise user instances are never updated and keep running a potentially very
old version of the binaries.
Now assuming that we have enough priviledge, it's possible to request
reexecution of all user instances:
systemctl kill --signal=SIGRTMIN+25 "user@*.service"
Note that this request is obviously asynchronous as it relies on a
signal. Keeping "systemctl kill" as the only interface should be good enough to
make this obvious and that's the reason why another interface, such as
"systemctl --global daemon-reexec" has not been considered.
PID1 already uses SIGTERM for reexecuting hence sending it SIGRTMIN+25 is a
nop.
* Fixed typo
Before, the file claimed that some systemd units are created "from other
configuration". It should have read "from other configuration files".
Co-authored-by: Nozz <nozolo90@gmail.com>
Some extra safety when invoked via "sudo". With this we address a
genuine design flaw of sudo, and we shouldn't need to deal with this.
But it's still a good idea to disable this surface given how exotic it
is.
Prompted by #5666
I'm not sure if the LogTarget property is sufficiently general to be made into
a property that can be generally implemented. It is very closely tied to the internal
systemd logic. The other two seem fine thoough.
Add note for change of behaviour in systemd-notify, where parent pid trick
is only used when --no-block is passed, and with enough privileges ofcourse.
Also, fix a small error in systemd(1).
As usual, the formatting was fixed and various obvious updates
were done, but nothing major.
I removed documentation of snapshots and related methods though.
