This adds an additional name check when cross-matching new group
entries against existing users, which allows coalescing entries
matching both ID and name.
It provides a small idempotence enhancement when creating groups
in cases where matching user entries are in place. By fine-tuning
the conflict detection logic, this avoids picking up new random
IDs and correctly prefers configuration values instead.
In the Xen case, it's the hypervisor which manages kexec. We thus
have to ask it whether a kernel is loaded, instead of relying on
/sys/kernel/kexec_loaded.
Also, fix a race condition introduced by d16684fe13:
```
[ 16.904218] H testsuite-26.sh[394]: + systemd-run --unit failed.service /bin/false
[ 16.964783] H systemd[845]: failed.service: Executing: /bin/false
[ 16.965062] H systemd[1]: Started failed.service.
[ 16.965462] H testsuite-26.sh[844]: Running as unit: failed.service
[ 16.966390] H testsuite-26.sh[394]: + systemctl is-failed failed.service
[ 16.977970] H testsuite-26.sh[846]: active
[ 16.978403] H systemd[1]: failed.service: Main process exited, code=exited, status=1/FAILURE
[ 16.978478] H systemd[1]: failed.service: Failed with result 'exit-code'.
```
If another bound interface (dummy98) will be removed before that dummy99
is processed by udevd, then removing dummy98 in the next step makes the
target interface (test1) bring down.
Follow-up for 3e2f7c46da.
Many long-running services will reload configuration and therefore
credentials on reload. Therefore its useful if a service reload will
also update credentials.
Tested in https://github.com/numtide/systemd-vaultd/pull/12
Using fsopen()/fsconfig(), we can check if hidepid/subset are supported to
avoid the noisy logs from the kernel if they aren't supported. This works
on centos/redhat 8 as well since they've backported fsopen()/fsconfig().
Instead of succeeding when either the firmware reports a TPM device
or we find a TPM device, let's check that the firmware reports a TPM
device and the TPM subsystem is enabled in the kernel.
To check whether the subsystem enabled, we check if the relevant
subdirectory in /sys exists at all.
