Do not rely on nl_pid == 0, but check the groups instead. We currently avoid using
nl_pid == 0 for unicast anyway, so this should be redundant, but let's try to be
correct.
The error code is called EDEADLK, stop using legacy names like EDEADLOCK.
Note that _some_ weird architectures define them differently (namely, mips
and sparc), but on all sane architectures they're exactly the same. So
stay with the widely used code, which is EDEADLK.
journal-remote buffers input, and then parses it handling one journal entry at a time.
It was possible for useful data to be left in the buffer after some entries were
processesed. But all data would be already read from the fd, so there would be
no reason for the event loop to call the handler again. After some new data came in,
the handler would be called again, and would then process the "old" data in the buffer.
Fix this by enabling a handler wherever we process input data and do not exhaust data
from the input buffer (i.e. when EAGAIN was not encountered). The handler runs until
we encounter EAGAIN.
Looping over the input data is done in this roundabout way to allow the event loop
to dispatch other events in the meanwhile. If the loop was inside the handler, a
source which produced data fast enough could completely monopolize the process.
https://bugs.freedesktop.org/show_bug.cgi?id=89516
"Notifications are of informal nature and no reply is expected, therefore the
sequence number is typically set to 0."[1]
If networkd is started soon after recent netlink activity, then there
will be messages with sequence number 0 in the buffer.
The first thing networkd does is to request a dump of all the links. If
it uses sequence number 0 for this, then it may confuse the dump request's
response with that of a notification.
This will result in it failing to properly enumerate all the links,
but more importantly, when it comes to enumerate all the addresses, it
will still have the link dump in progress, so the address enumeration
will fail with -EBUSY.
[1]: http://www.infradead.org/~tgr/libnl/doc/core.html#core_msg_types
[tomegun: sequence -> serial]
Newly added kernel drivers repeatedly pass our blacklist and
cause trouble for the devices, because they do not expect to
be examined by udev's default rules which include blkid.
This turns the blacklist into a whitelist. Device type which
need support for additional symlinks need to be added to the
whitelist now.
Note, that the by-id, by-path symlinks are only intended for
hotpluggable devices. There is no reason for exotic, or for
statically configured devices to provide them.
The information in the db is stale, so it does not make sense to
expose it any longer. Also, don't drop the kernel event, but simply
pass it on to userspace without ammending it.
We were explicitly eagerly loading the db, then deletenig the backing file and then processing the
rules/symlinks. Instead we delete the backnig db file as the last step and let the db loading be
lazy as everywhere else.
This may save us a bit of work in casese where the db is not needed, but more importantly it hides
some implementation details of libudev-device form udevd.
On kdbus, we get cgroups-agent messages via the system bus, not the
private systemd socket. Therefore, we must install the match properly or
we will never receive cgroup notifications.
Forwarding messages that are not rewinded will drop data. Fix this for
cgroups-agent messages that we might remarshal before forwarding to the
system bus.
If we receive an sd_bus_message from the kernel, m->kdbus will contain
additional items that cannot be used when sending a message. Therefore,
always remarshal the message if it is used again.
