Let's clean up hostname_is_valid() a bit: let's turn the second boolean
argument into a more explanatory flags field, and add a flag that
accepts the special name ".host" as valid. This is useful for the
container logic, where the special hostname ".host" refers to the "root
container", i.e. the host system itself, and can be specified at various
places.
let's also get rid of machine_name_is_valid(). It was just an alias,
which is confusing and even more so now that we have the flags param.
Back in 5248e7e1f1 (July 2017) we moved over to
"_gateway", with the old name declared to be temporary measure. Since we're
doing a bunch of changes to resolved now, it seems to be a good moment to make
this simplification and not add support for the compat name in new code.
As described in #15603, it is a fairly common setup to use a fqdn as the
configured hostname. But it is often convenient to use just the actual
hostname, i.e. until the first dot. This adds support in tmpfiles, sysusers,
and unit files for %l which expands to that.
Fixes#15603.
It's not that I think that "hostname" is vastly superior to "host name". Quite
the opposite — the difference is small, and in some context the two-word version
does fit better. But in the tree, there are ~200 occurrences of the first, and
>1600 of the other, and consistent spelling is more important than any particular
spelling choice.
All users of the macro (except for one, in serialize.c), use the macro in
connection with read_line(), so they must include fileio.h. Let's not play
libc games and require multiple header file to be included for the most common
use of a function.
The removal of def.h includes is not exact. I mostly went over the commits that
switch over to use read_line() and add def.h at the same time and reverted the
addition of def.h in those files.
These lines are generally out-of-date, incomplete and unnecessary.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.
This commit updates networkd behavior to check if the hostname option
received via DHCP is too long for Linux limit, and in case shorten it.
An overlong hostname will be truncated to the first dot or to
`HOST_MAX_LEN`, whatever comes earlier.
First of all, let's rename it to read_etc_hostname(), to make clearer
what kind of configuration it actually reads: the file format defined in
/etc/hostname and nothing else.
Secondly: let's port this to use read_line(), i.e. the new way to read
lines from a file in a safe, bounded way.
Thirdly: let's strip leading/trailing whitespace from what we are
reading. Given that we are already pretty lenient what we read (comments
and empty lines), let's be permissive regarding whitespace too.
Fourthly: let's actually validate the hostname when reading it. So far
we tried to make it valid, but that's not always possible (for example,
we can't make an empty hostname valid, ever).
This changes the symbolic name for the default gateway from "gateway" to
"_gateway". A new configuration option -Dcompat-gateway-hostname=true|false
is added. If it is set, the old name is also supported, but the new name
is used as the canonical name in either case. This is intended as a temporary
measure to make the transition easier, and the option should be removed
after a few releases, at which point only the new name will be used.
The old "gateway" name mostly works OK, but hasn't gained widespread acceptance
because of the following (potential) conflicts:
- it is completely legal to have a host called "gateway"
- there is no guarantee that "gateway" will not be registered as a TLD, even
though this currently seems unlikely. (Even then, there would be no
conflict except for the case when the top-level domain itself was being resolved.
The "gateway" or "_gateway" labels have only special meaning when the
whole name consists of a single label, so resolution of any subdomain
of the hypothetical gateway. TLD would still work OK. )
Moving to "_gateway" avoids those issues because underscores are not allowed
in host names (RFC 1123, §2.1) and avoids potential conflicts with local or
global names.
v2:
- simplify the logic to hardcode "_gateway" and allow
-Dcompat-gateway-hostname=true as a temporary measure.
Currently, if the hostname is not set gethostname_malloc() defaults to
the "sysname", which is "linux" on Linux. Let's change that to also
honour the compile-time fallback hostname as specified on the configure
command line.
Rework 17eb9a9ddb a bit.
Let's make sure we don't clobber the input parameter args[1], following our
coding style to not clobber parameters unless explicitly indicated. (in
particular, as we don't want to have our changes appear in the command line
shown in "ps"...)
No functional change.
".localdomain" is not a reserved suffix (or prefix). I'm not aware of any
product expecting *.localdomain to resolve to localhost, however I am aware of
at least one product that defaults to ".localdomain" as its DNS suffix provided
via DHCP (pfSense). This leads to unexpected results when attempting to access
a host that's offline (or a host that's online, when nsswitch.conf is
[mis-]configured to have myhostname ahead of DNS).
Operate on:
localhost (and localhost.)
*.localhost (and *.localhost.)
localhost.localdomain (and localhost.localdomain.)
*.localhost.localdomain (and *.localhost.localdomain.)
We should not cover:
*.localdomain (nor *.localdomain.)
localdomain (nor localdomain.)
Throughout the tree there's spurious use of spaces separating ++ and --
operators from their respective operands. Make ++ and -- operator
consistent with the majority of existing uses; discard the spaces.
Let's add some minimalistic LLDP sender support. The idea is that this is
either on or off, and all fields determined automatically rather than
configured explicitly.
There are more than enough calls doing string manipulations to deserve
its own files, hence do something about it.
This patch also sorts the #include blocks of all files that needed to be
updated, according to the sorting suggestions from CODING_STYLE. Since
pretty much every file needs our string manipulation functions this
effectively means that most files have sorted #include blocks now.
Also touches a few unrelated include files.
This moves is_gateway() from nss-myhostname into the basic APIs, and
makes it more like is_localhost(). Also, we rename it to
is_gateway_hostname() to make it more expressive.
Sharing this function in src/basic/ allows us to reuse the function for
routing name requests in resolved (in a later commit).
Tests are modified to check behaviour with relax and without relax.
New tests are added for hostname_cleanup().
Tests are moved a new file (test-hostname-util) because there's
now a bunch of them.
New parameter is not used anywhere, except in tests, so there should
be no observable change.
Lennart Poettering