This makes the output more predictable. Also, interesting interfaces
are often the low-numbered ones (actual hardware links, not virtual
devices stacked on top), and this makes them more visible.
Those lists are very long and use up a significant chunk of screen real estate.
But the contents are mostly static (usually they just reflect built-in
configuration). Let's just not show them in 'status' output. They can still
be viewed with 'nta' verb.
This is a follow-up for 9f83091e3c.
Instead of reading the mtime off the configuration files after reading,
let's do so before reading, but with the fd we read the data from. This
is not only cleaner (as it allows us to save one stat()), but also has
the benefit that we'll detect changes that happen while we read the
files.
This also reworks unit file drop-ins to use the common code for
determining drop-in mtime, instead of reading system clock for that.
We ask for the TTL, then have enough space for it.
We probably can drop the extra cmsg space now, but let's figure that out
another time, since the extra cmsg space is used elsewhere in resolved
as well.
Resolved can't reliably determine on whether "it makes sense" to query
AAAA records when not explicitly specifying it in the request, so we
shouldn't remove them.
After having done the resolving, applications can use RFC6724 to
determine whether that address is reachable.
We can't know whether an address is reachable before having resolved it
and inspecting the routing table, and not resolving AAAA just because
there's no IPv6 default route on the main interface link them breaks
various setups, including IPv6-providing wireguard tunnels on a
non-dualstacked environment.
Fixes#5782Fixes#5915Fixes#8017
This also makes sure the control buffer is properly aligned. This
matters, as otherwise the control buffer might not be aligned and the
cmsg buffer counting might be off. The incorrect alignment is becoming
visible by using recvmsg_safe() as we suddenly notice the MSG_CTRUNC bit
set because of this.
That said, apparently this isn't enough to make this work on all
kernels. Since I couldn't figure this out, we now add 1K to the buffer
to be sure. We do this once already, also for a pktinfo structure
(though an IPv4/IPv6) one. I am puzzled by this, but this shouldn't
matter much. it works locally just fine, except for those ubuntu CI
kernels...
While we are at it, make some other changes too, to simplify and
modernize the function.
We always need to make them unions with a "struct cmsghdr" in them, so
that things properly aligned. Otherwise we might end up at an unaligned
address and the counting goes all wrong, possibly making the kernel
refuse our buffers.
Also, let's make sure we initialize the control buffers to zero when
sending, but leave them uninitialized when reading.
Both the alignment and the initialization thing is mentioned in the
cmsg(3) man page.
We need to use the CMSG_SPACE() macro to size the control buffers, not
CMSG_LEN(). The former is rounded up to next alignment boundary, the
latter is not. The former should be used for allocations, the latter for
encoding how much of it is actually initialized. See cmsg(3) man page
for details about this.
Given how confusing this is, I guess we don't have to be too ashamed
here, in most cases we actually did get this right.
If we're using a set with _put_strdup(), most of the time we want to use
string hash ops on the set, and free the strings when done. This defines
the appropriate a new string_hash_ops_free structure to automatically free
the keys when removing the set, and makes set_put_strdup() and set_put_strdupv()
instantiate the set with those hash ops.
hashmap_put_strdup() was already doing something similar.
(It is OK to instantiate the set earlier, possibly with a different hash ops
structure. set_put_strdup() will then use the existing set. It is also OK
to call set_free_free() instead of set_free() on a set with
string_hash_ops_free, the effect is the same, we're just overriding the
override of the cleanup function.)
No functional change intended.
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.