It is almost always incorrect to allow DHCP or other sources of
transient host names to override an explicitly configured static host
name.
This commit changes things so that if a static host name is set, this
will override the transient host name (eg: provided via DHCP). Transient
host names can still be used to provide host names for machines that have
not been explicitly configured with a static host name.
The exception to this rule is if the static host name is set to
"localhost". In those cases we act as if no
static host name has been explicitly set.
As discussed elsewhere, systemd may want to have an fd based ownership
of the transient name. That part is not included in this commit.
Existing --pretty, --transient, --static options, used previously
for 'set-hostname' verb, are reused for the 'status' verb. If one
of them is given, only the specified hostname is printed. This
way there's no need to employ awk to get the hostname in a script.
Use proper grammar, word usage, adjective hyphenation, commas,
capitalization, spelling, etc.
To improve readability, some run-on sentences or sentence fragments were
revised.
[zj: remove the space from 'file name', 'host name', and 'time zone'.]
Option listings seemed to be pretty much random, some were short opt,
long opt, others were long opt, short opt. This just makes every option
with a short and long opt that I could find in the order short opt, long
opt, for formatting's sake.
man rules were repeating the same information in too many places,
which was error prone. Those rules can be easily generated from .xml
files. For efficiency and because python is not a required dependency,
Makefile-man.am is only regenerated when requested with
make update-man-list
If no metadata in man/*.xml changed, this file should not change. So
only when a new man page or a new alias is added, this file should
show up in 'git diff'. The change should then be committed.
If the support for building from git without python was dropped, we
could drop Makefile-man.am from version control. This would also
increase the partial build time (since more stuff would be rebuild
whenever sources in man/*.xml would be modified), so it would probably
wouldn't be worth it.
For many usecases it is useful to store the chassis type somewhere, and
/etc/machine-info sounds like a good place. Ideally we could always
detect the chassis type from firmware, but frequently that's not
available and in many embedded devices probably entirely unrealistic.
This patch adds a configurable setting CHASSIS= to /etc/machine-info and
exposes this via hostnamectl/hostnamed. hostnamed will guess the chassis
type from DMI if nothing is set explicitly. I also added support for
detecting it from ACPI, which should be more useful as ACPI 5.0 actually
knows a "tablet" chassis type, which neither DMI nor previous ACPI
versions knew.
This also enables DMI-based and ACPI-based detection for non-x86 systems
as ACPI is apparently coming to ARM platforms soon.
I tried to minimize the vocabulary of chassis types understood and
added: desktop, laptop, server, tablet, handset. This is much less than
either APCI or DMI know. If we need more types later on we can easily
add them.
