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)
Let's add flavours for copying stub/uplink resolv.conf versions.
Let's add a more brutal "replace" mode, where we'll replace any existing
destination file.
Let's also change what "auto" means: instead of copying the static file,
let's use the stub file, so that DNS search info is copied over.
Fixes: #15340
Some fdopendir() calls remain where safe_close() is manually
performed, those could be simplified as well by converting to
use the _cleanup_close_ machinery, but makes things less trivial
to review so left for a future cleanup.
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.
This has been requested many times before. Let's add it finally.
GPT auto-discovery for /var is a bit more complex than for other
partition types: the other partitions can to some degree be shared
between multiple OS installations on the same disk (think: swap, /home,
/srv). However, /var is inherently something bound to an installation,
i.e. specific to its identity, or actually *is* its identity, and hence
something that cannot be shared.
To deal with this this new code is particularly careful when it comes to
/var: it will not mount things blindly, but insist that the UUID of the
partition matches a hashed version of the machine-id of the
installation, so that each installation has a very specific /var
associated with it, and would never use any other. (We actually use
HMAC-SHA256 on the GPT partition type for /var, keyed by the machine-id,
since machine-id is something we want to keep somewhat private).
Setting the right UUID for installations takes extra care. To make
things a bit simpler to set up, we avoid this safety check for nspawn
and RootImage= in unit files, under the assumption that such container
and service images unlikely will have multiple installations on them.
The check is hence only required when booting full machines, i.e. in
in systemd-gpt-auto-generator.
To help with putting together images for full machines, PR #14368
introduces a repartition tool that can automatically fill in correctly
calculated UUIDs on first boot if images have the var partition UUID
initialized to all zeroes. With that in place systems can be put
together in a way that on first boot the machine ID is determined and
the partition table automatically adjusted to have the /var partition
with the right UUID.
To support ProtectHome=y in a user namespace (which mounts the inaccessible
nodes), the nodes need to be accessible by the user. Create these paths and
devices in the user runtime directory so they can be used later if needed.
This makes --overlay=+/foobar::/foobar work again, i.e. where the middle
parameter is left out. According to the documentation this is supposed
to generate a temporary writable work place in the midle. But it
apparently never did. Weird.
If /sys is read only filesystem, e.g., nspawn is running in container,
then usually udev is not running. In such a case, let's assume that
the interface is already initialized. Also, this makes nspawn refuse
to use the network interface which is under renaming.
Fixes#14223.
This will call json_variant_sensitive() internally while parsing for
each allocated sub-variant. This is better than calling it a posteriori
at the end, because partially parsed variants will always be properly
erased from memory this way.
