Let's modernize userdbd furzer, and use the common child handling we
nowadays have in sd-event, instead of rolling our own.
This also means we'll start using pidfds where we can.
Let's make use of SD_EVENT_SIGNAL_PROCMASK so that we don't have to mask
the signals manually. Let's use sd_event_set_exit_signal() instead of
rolling our own SIGTERM/SIGINT handling. Let's use "floating" event
sources instead of keeping references on our own.
Let's also debug log if we can't enable watchdog handling.
-1 was used everywhere, but -EBADF or -EBADFD started being used in various
places. Let's make things consistent in the new style.
Note that there are two candidates:
EBADF 9 Bad file descriptor
EBADFD 77 File descriptor in bad state
Since we're initializating the fd, we're just assigning a value that means
"no fd yet", so it's just a bad file descriptor, and the first errno fits
better. If instead we had a valid file descriptor that became invalid because
of some operation or state change, the other errno would fit better.
In some places, initialization is dropped if unnecessary.
RUN_WITH_UMASK was initially conceived for spawning externals progs with the
umask set. But nowadays we use it various syscalls and stuff that doesn't "run"
anything, so the "RUN_" prefix has outlived its usefulness.
(s) is just ugly with a vibe of DOS. In most cases just using the normal plural
form is more natural and gramatically correct.
There are some log_debug() statements left, and texts in foreign licenses or
headers. Those are not touched on purpose.
All users were setting this to some static string (usually "-"), so let's
simplify things by not doing strdup, but instead limiting callers to a fixed
set of values. In preparation for the next commit, the function is renamed from
"empty" to "replacement", because it'll be used for more than empty fields. I
didn't do the whole string-table setup, because it's all used internally in one
file and this way we can immediately assert if an invalid value is passed in.
Some callers were (void)ing the error, others were ignoring it, and others
propagating. It's nicer to remove the boilerplate.
This renames UidRange -> UidRangeEntry, and reintroduces UidRange which
contains the array of UidRangeEntry and its size.
No fucntional changes, just refactoring.
Containers generally have a smaller UID range assigned than host
systems. Let's visualize this in the user/group tables. We insert
markers for unavailable regions. This way display is identical to status
quo ante on host systems, but in containers unavailable ranges will be
shown as that.
And while we are at it, also hide well-known UID ranges when they are
outside of userns uid_map range. This is mostly about the "container"
range. It's pointless showing the cotnainer range (i.e. a range UID >
65535) if that range isn#t available in the container anyway.
The approach to use '''…'''.split() instead of a list of strings was initially
used when converting from automake because it allowed identical blocks of lines
to be used for both, making the conversion easier.
But over the years we have been using normal lists more and more, especially
when there were just a few filenames listed. This converts the rest.
No functional change.
Similar in style to previous commit, let's handle these two errors
properly, i.e. as equivalent to no entries found. Let's debug log about
them, to make things either to deal with when debugging (after all
userdbctl to a large degree are debugging tools).
The lower-level userdb code will return ENOLINK if varlink lookups are
disabled explicitly and we couldn#t find an answer any other way. Let's
not propagate this to clients, since they don't have control over this
feature anyway: we decide internally when to disable varlink lookups
(e.g. if DropIn lookups are requested we disable them) and to the client
side that should not be visible: if we can't find a record with the
flags we pick then we should report then we can't find any, and that's
it.
Fixes: #21223
LLVM 13 introduced `-Wunused-but-set-variable` diagnostic flag, which
trips over some intentionally set-but-not-used variables or variables
attached to cleanup handlers with side effects (`_cleanup_umask_`,
`_cleanup_(notify_on_cleanup)`, `_cleanup_(restore_sigsetp)`, etc.):
```
../src/basic/process-util.c:1257:46: error: variable 'saved_ssp' set but not used [-Werror,-Wunused-but-set-variable]
_cleanup_(restore_sigsetp) sigset_t *saved_ssp = NULL;
^
1 error generated.
```
In general we almost never hit those asserts in production code, so users see
them very rarely, if ever. But either way, we just need something that users
can pass to the developers.
We have quite a few of those asserts, and some have fairly nice messages, but
many are like "WTF?" or "???" or "unexpected something". The error that is
printed includes the file location, and function name. In almost all functions
there's at most one assert, so the function name alone is enough to identify
the failure for a developer. So we don't get much extra from the message, and
we might just as well drop them.
Dropping them makes our code a tiny bit smaller, and most importantly, improves
development experience by making it easy to insert such an assert in the code
without thinking how to phrase the argument.
We want user records to be extensible, hence we shouldn't complain about
fields we can't parse. In particular we want them to be extensible for
our own future extensions.
Some code already turned the permissive flag when parsing the JSON data,
but most did not. Fix that. A few select cases remain where the bit is
not set: where we just gnerated the JSON data ourselves, and thus can be
reasonably sure that if we can't parse it it's our immediate programming
error and not just us processing a user record from some other tool or a
newer version of ourselves.
So far we basically had two ways to iterate through NSS records: one via
the varlink IPC and one via the userdb.[ch] infra, with slightly
different implementations.
Let's clean this up, and always use userdb.[ch] also when resolving via
userdbd. The different codepaths for the NameServiceSwitch and the
Multiplexer varlink service now differ only in the different flags
passed to the userdb lookup.
Behaviour shouldn't change by this. This is mostly refactoring, reducing
redundant codepaths.
Let's use "exclude" for flags that really exclude records from our
lookup. Let's use "avoid" referring to concepts that when flag is set
we'll not use but we have a fallback path for that should yield the same
result. Let' use "suppress" for suppressing partial info, even if we
return the record otherwise.
So far we used "avoid" for all these cases, which was confusing.
Whiel we are at it, let's reassign the bits a bit, leaving some space
for bits follow-up commits are going to add.
Lennart Poettering
Jan Janssen
Zbigniew Jędrzejewski-Szmek
Yu Watanabe
David Tardon
Thomas Weißschuh
Dan Streetman
Frantisek Sumsal