Let's be extra careful whenever we return from recvmsg() and see
MSG_CTRUNC set. This generally means we ran into a programming error, as
we didn't size the control buffer large enough. It's an error condition
we should at least log about, or propagate up. Hence do that.
This is particularly important when receiving fds, since for those the
control data can be of any size. In particular on stream sockets that's
nasty, because if we miss an fd because of control data truncation we
cannot recover, we might not even realize that we are one off.
(Also, when failing early, if there's any chance the socket might be
AF_UNIX let's close all received fds, all the time. We got this right
most of the time, but there were a few cases missing. God, UNIX is hard
to use)
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.
When the stub listener is disabled, stub-resolv.conf is useless. Instead of
warning about this, let's just make stub-resolv.conf point to the private
resolv.conf file. (The original bug report asked for "mirroring", but I think
a symlink is nicer than a copy because it is easier to see that a redirection
was made.)
Fixes#14700.
All callers ignore the return value.
This is almost entirely theoretical, since writing to /run is unlikely to
fail..., but the user is almost certainly better off keeping the old copy
around and having working dns resolution with an out-of-date dns server list
than having having a dangling /etc/resolv.conf symlink.
An error with a full path is immediately clear. OTOH, a user might not be
familiar with concenpt like "private resolv.conf".
I opted to use %s-formatting for the path, because the code is much easier to
read this way. Any difference in t speed of execution is not important.
This is useful to raise the log level for a single transaction or a few,
without affecting other state of the resolved as a restart would.
The log level can only be set, I didn't bother with having the ability
to restore the original as in pid1.
There are legitimate reasons to access the file directly, as currently
discussed on fedora-devel. Hence tone things down from "must" to "should
typically not".
Also, let's use fputs() instead of fputs_unlocked() here,
fopen_temporary_label() turns off stdio locking anyway for the whole
FILE*, hence no need to do this manually each time.
On certain distributions such as NixOS the mtime of `/etc/hosts` is
locked to a fixed value. In such cases, only checking the last mtime of
`/etc/hosts` is not enough - we also need to check if the st_ino/st_dev
match up. Thus, let's make sure make sure that systemd-resolved also
rereads `/etc/hosts` if the inode or the device containing `/etc/hosts` changes.
Test script:
```bash
hosts="/etc/hosts"
echo "127.0.0.1 testpr" > "hosts_new"
mv "hosts_new" "$hosts"
resolvectl query testpr || exit 1
mtime="$(stat -c %y "$hosts")"
echo "127.0.0.1 newhost" > "hosts_tmp"
touch -d "$mtime" "hosts_tmp"
install -p "hosts_tmp" "$hosts"
sleep 10
resolvectl query newhost || exit 1
rm -f "hosts_tmp"
```
Closes#14456.
Widely accepted certificates for IP addresses are expensive and only
affordable for larger organizations. Therefore if the user provides
the hostname in the DNS= option, we should use it instead of the IP
address.
Section 6.2 of RFC4034 requires that "all uppercase US-ASCII letters in
the DNS names contained within the RDATA are replaced by the corresponding
lowercase US-ASCII letters" for a long list of RR types.
Fixes#14891
In subsequent commits, calls to if_nametoindex() will be replaced by a wrapper
that falls back to alternative name resolution over netlink. netlink support
requires libsystemd (for sd-netlink), and we don't want to add any functions
that require netlink in basic/. So stuff that calls if_nametoindex() for user
supplied interface names, and everything that depends on that, needs to be
moved.
We don't need a seperate output parameter that is of type int. glibc() says
that the type is "unsigned", but the kernel thinks it's "int". And the
"alternative names" interface also uses ints. So let's standarize on ints,
since it's clearly not realisitic to have interface numbers in the upper half
of unsigned int range.
If a daemon is not started as root, most likely it also can't create its
directory and let's not try to resolve the user in that case either.
Create /run/systemd/netif/lldp with tmpfiles.d like other netif directories.
This is also very helpful for preparing a RootImage for the daemons as NSS crud
is not needed.
This cleans up and unifies the outut of --help texts a bit:
1. Highlight the human friendly description string, not the command
line via ANSI sequences. Previously both this description string and
the brief command line summary was marked with the same ANSI
highlight sequence, but given we auto-page to less and less does not
honour multi-line highlights only the command line summary was
affectively highlighted. Rationale: for highlighting the description
instead of the command line: the command line summary is relatively
boring, and mostly the same for out tools, the description on the
other hand is pregnant, important and captions the whole thing and
hence deserves highlighting.
2. Always suffix "Options" with ":" in the help text
3. Rename "Flags" → "Options" in one case
4. Move commands to the top in a few cases
5. add coloring to many more help pages
6. Unify on COMMAND instead of {COMMAND} in the command line summary.
Some tools did it one way, others the other way. I am not sure what
precisely {} is supposed to mean, that uppercasing doesn't, hence
let's simplify and stick to the {}-less syntax
And minor other tweaks.
Validate the IP address in the certificate for DNS-over-TLS in strict mode when GnuTLS is used. As this is not yet the case in contrast to the documentation.
Increase the required version to ensure TLS 1.3 is always supported when using GnuTLS for DNS-over-TLS and allow further changes to use recent API additions.
Notifications are only sent for the top object, and not for individual
links. This should be enough for the most obvious cases where somebody
just cares about the effective set of servers.
Fixes#13721.
