When trying to mount a partition that is encrypted without the
encryption first having been set up we want to return a
recognizable error (EUNATCH). This was broken by
80ce8580f5 which added an allowlist check
for permissible file systems first. Let's reverse the check order, so
that we get EUNATCH again, as before. (And leave EIDRM as error for the
failed allowlist check).
See added code comment for a longer explanation. TLDR: Linux maintains
distinct block device caches for partition and "whole" block devices,
and a simply BLKFLSBUF should make the worst confusions this causes go
away.
The function path_prefix_root_cwd() was introduced for prefixing the
result from chaseat() with root, but
- it is named slightly generic,
- the logic is different from what chase() does.
This makes the name more explanative and specific for the result of the
chaseat(), and make the logic consistent with chase().
Fixes https://github.com/systemd/systemd/pull/27199#issuecomment-1511387731.
Follow-up for #27199.
E.g. in logs on jammy-ppc64el in https://github.com/systemd/systemd/pull/27294:
Apr 16 17:42:50 H systemd-gpt-auto-generator[300]: Failed to dissect partition table of block device /dev/sda: No message of desired type
Apr 16 17:42:50 H (sd-execu[295]: /usr/lib/systemd/system-generators/systemd-gpt-auto-generator failed with exit status 1.
ee0e6e476e made this particular condition not an
error. But for other errnos we want to print a better message too.
dissect_loop_device_and_warn() already does this, but it always prints the
error at error level. We want to suppress some of the errors, so let's make the
print helper public and do the error suppression in the caller.
This makes the bpf LSM check generic, so that we can use it elsewhere.
it also drops the caching inside it, given that bpf-lsm code in PID1
will cache it a second time a stack frame further up when it checks for
various other bpf functionality.
Running systemd with IP accounting enabled generates many bpf maps (two
per unit for accounting, another two if IPAddressAllow/Deny are used).
Systemd itself knows which maps belong to what unit and commands like
`systemctl status <unit>` can be used to query what service has which
map, but monitoring these values all the time costs 4 dbus requests
(calling the .IP{E,I}gress{Bytes,Packets} method for each unit) and
makes services like the prometheus systemd_exporter[1] somewhat slow
when doing that for every units, while less precise information could
quickly be obtained by looking directly at the maps.
Unfortunately, bpf map names are rather limited:
- only 15 characters in length (16, but last byte must be 0)
- only allows isalnum(), _ and . characters
If it wasn't for the length limit we could use the normal unit escape
functions but I've opted to just make any forbidden character into
underscores for maximum brievty -- the map prefix is also rather short:
This isn't meant as a precise mapping, but as a hint for admins who want
to look at these.
(Note there is no problem if multiple maps have the same name)
Link: https://github.com/povilasv/systemd_exporter [1]
This removes remaining hardcoded occurences of `/sbin/fsck`, and instead
uses `find_executable` to find `fsck`.
We also use `fsck_exists_for_fstype` to check for the `fsck.*`
executable, which also checks in `$PATH`, so it's fair to assume fsck
itself is also available.
The ignore directive specifies to not do anything with the given
unit and leave existing configuration intact. This allows distributions
to gradually adopt preset files by shipping a ignore * preset file.
strstrafter() is like strstr() but returns a pointer to the first
character *after* the found substring, not on the substring itself.
Quite often this is what we actually want.
Inspired by #27267 I think it makes sense to add a helper for this,
to avoid the potentially fragile manual pointer increment afterwards.
Oftentimes it is useful to allow the per-service fd store to survive
longer than for a restart. This is useful in various scenarios:
1. An fd to some security relevant object needs to be stashed somewhere,
that should not be cleaned automatically, because the security
enforcement would be dropped then.
2. A user namespace fd should be allocated on first invocation and be
kept around until the user logs out (i.e. systemd --user ends), á la
#16328 (This does not implement what #16318 asks for, but should
solve the use-case discussed there.)
3. There's interest in allow a concept of "userspace reboots" where the
kernel stays running, and userspace is swapped out (i.e. all services
exit, and the rootfs transitioned into a new version of it) while
keeping some select resources pinned, very similar to how we
implement a switch root. Thus it is useful to allow services to exit,
while leaving their fds around till the very end.
This is exposed through a new FileDescriptorStorePreserve= setting that
is closely modelled after RuntimeDirectoryPreserve= (in fact it reused
the same internal type), since we want similar behaviour in the end, and
quite often they probably want to be used together.
Let's honour the flag if it is set, just to be safe.
(This only handles the case for the writing side: whenever the client
code hands us a json object with the flag set we'll honour it till the
it's out of reach for us. This does *not* handle the reading side, which
is left for a later patch once needed. We probably should add a
per-connection flag that simply globally enables the sensitive logic for
all messages coming in on a specific varlink conneciton.)
Let's add infrastructure to implement fd passing in varlink, when used
over AF_UNIX.
This will optionally associate one or more fds with a message sent via
varlink and deliver it to the server.
Some minor refactoring. This adds a helper call whose only job is to
unref the JSON object of the currently processed incoming message.
This doesn't make too much sense on its own, given this just replaces
one line by another. However, in a later patch when we'll add fd passing
we'll extend the function to also destroy associated fds, and then it
will start to make more sense.
So far, if we do a synchronous varlink call from the client side via
varlink_call(), we'll
move the returned json object from "v->current" into "v->reply", and
keep it referenced there until the next call. We then return a pointer
to it. This ensures that the json object remains valid between two
varlink_call() invocations.
But the thing is, we don't need a separate field for that, we can just
leave the data in "v->current". This means VARLINK_IDLE_CLIENT state
will be permitted with and without v->current initialized. Initially,
after connection setup it will be set to NULL, but after the first
varlink_call() it will be set to the most recent response, pinning it
into memory.
Neither of the callers of bus_deserialize_and_dump_unit_file_changes()
touches the changes array, so let's simplify things and keep it internal
to the function.
David Tardon
Luca Boccassi
Frantisek Sumsal
Lennart Poettering
Daan De Meyer
Quintin Hill
Yu Watanabe
Zbigniew Jędrzejewski-Szmek
Dominique Martinet
Florian Klink
OMOJOLA JOSHUA DAMILOLA
Mike Yuan