This commit is the first in the series, and they generally follow the same
idea: we had very detailed logging for message append operations which would
only fail either with some type error or intrinsic limit (and then they would
fail everywhere, so this would be noticed during development or in CI), or they
would fail with ENOMEM, in which case the exact location is not very interesting
since this is not repeatable.
I am in general in favour of detailed logging messages, because it helps with
diagnosis of errors, but I think case is an exception. Despite not being very
useful, those messages required a lot of effort, because they were customized
for each and every append operation. In fact some of the messages contained copy
errors. The text of the messages (since they are generally unique) also added up
to a considerable size.
This removes the log messages after each sd_netlink_message_append_*() in
fill_message_create() with a single line in netdev_create(). As described
above, we are just appending fields to a message, so those calls would almost
never fail.
A forgotten 'return' was added in one place.
$ size build/systemd-networkd{.0,}
text data bss dec hex filename
1878634 394016 36 2272686 22adae build/systemd-networkd.0
1842450 394080 36 2236566 222096 build/systemd-networkd
… so we save 30k too.
Kernel manages each genl family by its name, e.g. "nlctrl" or WG_GENL_NAME,
and its ID (used for nlmsg_type) is determined dynamically when the
corresponding module is loaded.
This commit makes sd-netlink follow the same way; now, sd_genl_family_t
is dropped, and sd_genl_message_new() takes a genl family name. Each
genl family is resolved when it is used first time, and its information
is stored in GenericNetlinkFamily.
Zbigniew Jędrzejewski-Szmek
Yu Watanabe
Frantisek Sumsal
Annika Wickert