So far we had various ad hoc APIs to query search paths:
systemd-analyze unit-paths, lookup_paths_log(), the pkgconfig file,
debug logs emitted by systemd-analyze cat-config.
But answering a simple question "what is the search path for tmpfiles,
sysusers, .network files, ..." is surprisingly hard.
I think we should have an api that makes it easy to query this. Pkgconfig is
not bad, but it is primarily a development tool, so it's not available in many
context. Also it can't provide support for paths which are influenced by
environment variables, and I'd like to be able to answer the question "what is
the search path for ..., assuming that VAR_FOO=... is set?".
Extending sd-path to support more of our internal paths seems to be most
flexible solution. We already have systemd-path which provides a nice
way to query, and we can add stuff like optional descriptions later on.
We we essentially get a nice programmatic and commmandline apis for the price
of one.
The two functions were duplicating a lot of functionality and more
importantly, they both had explicit lists of types which are search
paths. I want to add more types, and I don't want to have to remember
to add them to both lists.
I think the two names were both pretty bad. They did not give a proper hint
what the difference between the two functions is, and sd_path_home sounds like
it is somehow related to /home or home directories or whatever, when in fact
both functions return the same set of paths as either a colon-delimited string
or a strv. "_strv" suffix is used by various functions in sd-bus, so let's
reuse that.
Those functions are not public yet, so let's rename.
In those functions where bus defaults to the m->bus, we should also
resolve the magic parameters. And if neither called with bus=NULL
and an unattached message, return properly instead of crashing in assert
later.
It fully initializes the address structure, so no need for pre-initialization,
and also returns the length of the address, so no need to recalculate using
SOCKADDR_UN_LEN().
socklen_t is unsigned, so let's not use an int for it. (It doesn't matter, but
seems cleaner and more portable to not assume anything about the type.)
When authorizing via PolicyKit we want to process incoming method calls
twice: once to process and figure out that we need PK authentication,
and a second time after we aquired PK authentication to actually execute
the operation. With this new call sd_bus_enqueue_for_read() we have a
way to put an incoming message back into the read queue for this
purpose.
This might have other uses too, for example debugging.
Let's remove a function of questionnable utility.
strv_clear() frees the items of a string array, but not the array
itself. i.e. it half-drestructs a string array and makes it empty. This
is not too useful an operation since we almost never need to just do
that, we also want to free the whole thing. In fact, strv_clear() is
only used in one of our .c file, and there it appears like unnecessary
optimization, given that for each array with n elements it leaves the
number of free()s we need to at O(n) which is not really an optimization
at all (it goes from n+1 to n, that's all).
Prompted by the discussions on #14605
