tree-wide: remove Emacs lines from all files This should be handled fine now by .dir-locals.el, so need to carry that stuff in every file.

sd-netlink: since whe acquire the netlink socket's sockaddr anyway, let's actually verify it

sd-netlink: don't take possesion of netlink fd from caller on failure Fixes: #2338

tree-wide: expose "p"-suffix unref calls in public APIs to make gcc cleanup easy GLIB has recently started to officially support the gcc cleanup attribute in its public API, hence let's do the same for our APIs. With this patch we'll define an xyz_unrefp() call for each public xyz_unref() call, to make it easy to use inside a __attribute__((cleanup())) expression. Then, all code is ported over to make use of this. The new calls are also documented in the man pages, with examples how to use them (well, I only added docs where the _unref() call itself already had docs, and the examples, only cover sd_bus_unrefp() and sd_event_unrefp()). This also renames sd_lldp_free() to sd_lldp_unref(), since that's how we tend to call our destructors these days. Note that this defines no public macro that wraps gcc's attribute and makes it easier to use. While I think it's our duty in the library to make our stuff easy to use, I figure it's not our duty to make gcc's own features easy to use on its own. Most likely, client code which wants to make use of this should define its own: #define _cleanup_(function) __attribute__((cleanup(function))) Or similar, to make the gcc feature easier to use. Making this logic public has the benefit that we can remove three header files whose only purpose was to define these functions internally. See #2008.

util-lib: split out allocation calls into alloc-util.[ch]

socket-util: move remaining socket-related calls from util.[ch] to socket-util.[ch]

util-lib: split out fd-related operations into fd-util.[ch] There are more than enough to deserve their own .c file, hence move them over.

util-lib: split our string related calls from util.[ch] into its own file string-util.[ch] There are more than enough calls doing string manipulations to deserve its own files, hence do something about it. This patch also sorts the #include blocks of all files that needed to be updated, according to the sorting suggestions from CODING_STYLE. Since pretty much every file needs our string manipulation functions this effectively means that most files have sorted #include blocks now. Also touches a few unrelated include files.

sd-netlink: refcount multicast groups Track the number of matches installed for a given multicast group, and leave the group once no matches depend on it. In order to handle passed-in sockets that are already members of multicast groups we initialize the refcount based on the membership once we take over the socket. This way we will leave the socket in the state we found it once we finish with it. On kernels that do not fully support reading out the multicast group membership we fall back to never leaving any groups (as before).

sd-netlink: add support for subscribing to ROUTE messages Also, explicitly don't support subscribing to GET or SET messages, as these will never be emitted by the kernel.

tree-wide: generate EBADF when we get invalid fds This is a follow-up to #907, and makes the same change for all our other public APIs.

sd-netlink: socket - move some functions from main source file

sd-netlink: drop the write-queue AF_NETLINK is not write-buffered, so this was actually never used.

sd-netlink: rename from sd-rtnl