Reverts systemd/systemd#38680
After taking a closer look I'm not convinced by the approach, see below.
First of all, all other SD_PATH_SEARCH_* are either somewhat generic,
i.e. encode the common prefix for configurations, binaries, etc., or are
subdirectories under systemd/ hence in our own "domain". The
tmpfiles/sysctl/binfmt we don't prefix with "systemd" precisely because
the concept is generic and there're actually other impls of them. A
specific SD_PATH_SEARCH_SYSCTL doesn't fit into our existing scheme.
Instead something along the lines of "SEARCH_SYSTEM_CONFIGURATION" shall
be introduced, and consumers will just suffix
sysctl.d/tmpfiles.d/binfmt.d for the final result.
And secondly, I don't grok why systemd-sysctl now unnecessarily calls
into sd-path to obtain the fixed search path. None of our other tools do
that.
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An alternate approach, SD_PATH_SYSTEM_SEARCH_CONFIGURATION, which does
exactly above, will be introduced instead. It provides a universal
interface for querying any system config with our idiomatic
/etc/:/run/:/usr/local/lib/:/usr/lib/ hierarchy.
Its value depends on how strerror_r() implemented, and the
implementations of the function in glibc and musl are actually
different. Let's drop the checks.
Defer and exit event sources are marked pending once when they are added
and never again afterwards. This means their pending_iteration is never
incremented after they are initially added, which breaks fairness among
event sources with equal priority which depend on the pending_iteration
variable getting updated in source_set_pending(). To fix this, let's assign
iterations for defer and exit sources in source_dispatch() instead so that
those get their pending_iteration updated as well.
Sometimes it's hard to assign responsibility to a specific event source
for exiting when there's no more work to be done. So let's add exit-on-idle
support where we exit when there are no more event sources.
As documented in sd_event_add_memory_pressure(), we can only add
the memory pressure fd to epoll once we've written the watch string,
so make sure we don't register the memory pressure in
event_source_online() until we've written the watch string.
More post event sources might get added during dispatching, we want
to make sure those become pending as well if we're dispatching a non-post
event source.
If we're switching users but not entering a container, then we can
assume that new switches for systemd-stdio-bridge are available, so
make use of them in that case.
This provides functionality to replace what was provided by the preceding
revert:
$ build/systemd-path system-search-configuration --suffix=sysctl.d
/etc/sysctl.d:/run/sysctl.d:/usr/local/lib/sysctl.d:/usr/lib/sysctl.d
The result is identical, but more generic, since by changing suffix we can also
get the answer for sysusers.d, tmpfiles.d, and any other of the directories
which follow the same general rule.
Add the new type SD_PATH_SEARCH_SYSCTL to libsystemd.
With this new type sd_path_lookup() and sd_path_lookup_strv() will
return the paths used by systemd-sysctl(1) to search the .conf files:
/etc/sysctl.d/
/run/sysctl.d/
/usr/local/lib/sysctl.d/
/usr/lib/sysctl.d/
Refer to sysctl.d(5) man page.
Note: the old type SD_PATH_SYSCTL is still available, and returns the
last path (/usr/lib/sysctl.d/).
In many cases we want to expose enums for which we have the usual
xyz_to_string()/xyz_from_string() via Varlink as enums. Let's add some
infra to test the tables against each other, to automatically detect
when they deviate.
In order to implement this properly, let's export/introduce clean
json_underscorefy()/json_dashify(), for dealing with the fact that our
enums usually use dash separates ames, but Varlink doesn't allow that.
(This does not add the test cases for all enum types we expose right
now, but only adds the general infra).
Let's use the proper uint32_t parsers initially, so that the usual logic
of formatting integers as decimal strings, works too for uids/gids. Not
because it made any sense to encode them like that, but just to be
systematic here.
Most of our dispatch helpers already do something useful in case they
are invoked on a null JSON value: they translate this to the appropriate
niche value for the type, if there is one.
Add the same for *all* dispatchers we have, to make this fully
systematic.
For various types it's not always clear which niche value to pick. I
opted for UINT{8,16,32,64}_MAX for the various unsigned integers, which
maps our own use in most cases. I opted for -1 for the various signed
integer types. For arrays/blobs of stuff I opted for the empty
array/blob, and for booleans I opted for false.
Of course, in various cases this is not going to be the right niche
value, but that's entirely fine, after all before a json value reaches a
dispatcher function it must pass one of two type checks first:
1. Either the .type field of sd_json_dispatch_field must be
_SD_JSON_VARIANT_TYPE_INVALID to not do a type check at all
2. Or the .type field is set, but then the SD_JSON_NULLABLE flag must be
set in .flags.
This means, accidentally generating the niche values on null is not
really likely.
Although extremely unlikely, there is a race present in solely checking the
$LISTEN_PID environment variable, due to PID recycling. Fix that by introducing
$LISTEN_PIDFDID, which contains the 64-bit ID of a pidfd for the child process
that is not subject to recycling.
- Make sure forward headers have the iwyu pragma to always keep them
- Make sure we always include the daemon specific forward header
instead of shared-forward.h
- Remove shared-forward.h include where the daemon specific forward
header is already included
Needed to implement support for RootHashSignature=/RootVerity=/RootHash=
and friends when going through mountfsd, for example with user units,
so that system and user units provide the same features at the same
level
When varlink parameters are empty, omit the "parameters" field entirely
rather than sending "parameters":{}. This reduces message size and
follows varlink specification which allows parameters to be omitted.
The implementation supports three equivalent representations for empty
parameters: field omission, JSON null, and empty object {}. All three
are accepted on input for backward compatibility.
Fixes: #38474
Let's not leak details from src/shared and src/libsystemd into
src/basic, even though you can't actually do anything useful with
just forward declarations from src/shared.
The sd-forward.h header is put in src/libsystemd/sd-common as we
don't have a directory for shared internal headers for libsystemd
yet.
Let's also rename forward.h to basic-forward.h to keep things
self-explanatory.
Yu Watanabe
Jelle van der Waa
Daan De Meyer
Zbigniew Jędrzejewski-Szmek
Mike Yuan
Goffredo Baroncelli
Lennart Poettering
Luca Boccassi
Daniel Foster
Luca Boccassi
Govind Venugopal