This allows us to drop the special sigterm handling in spawn_wait()
as this will now be passed directly to the worker event loop.
We now log failing spawend processes at 'warning' level, and timeouts
are in terms of CLOCK_BOOTTIME when available, otherwise the behavior
is unchanged.
Rather than trying to schedule new events on every main-loop iteration, do it explicitly when
processing an event finishes, a worker is killed, a new uevent is received, or the event queue
is explicitly restarted.
The behavior is mostly unchanged, but rather than only ever calling these functions at
fixed points in the event loop, they are called directly whenever they are invoked.
This partly reverts:
commit 6d1b1e0bc6
Author: Tom Gundersen <teg@jklm.no>
Date: Sun May 24 15:10:04 2015 +0200
udevd: worker - fully clean up unnecessary fds
The inotify-fd _is_ used in the workers, so don't close it! Have a look at
udev-watch.c, which keeps track of the inotify-fd as a global variable
(ugh!).
We would enforce that events could only be added to the queue from the
main process, but that brake in daemonized mode. Relax the restriction
to only allow one process to add events to the queue.
Reported by Mantas Mikulėnas.
We were returning rather than continuing in some cases. The intention
was always to fully process all pending events before returning
from the SIGCHLD handler. Restore this behaviour.
This way it is more obvious that the queue flag file is always
up-to-date. Moreover, we only have to touch/unlink it when the
first/last event is allocated/freed.
This avoids updating the flag files twice for every loop, and also removes another dependency
in the main-loop, so we are freer to reshufle it as we want.
Rather than skippling ctrl handling whenever we have handlede inotify events
(and hence may have synthesized a 'change' event), just call the uevent
handling explicitly from on_inotify() so that the event queue is up-to-date.
Make the worker context have the same life-span as the worker process. It is created on fork()
and free'd on SIGCHLD.
The change means that we can get worker_returned() for a worker context that is no longer around,
this is not a problem and we can just drop the message. The only use for worker_returned() is to
know to reschedule events to workers that are still around, so if the worker has already exited
it is not important to keep track of. We still print a debug statement in this case to be on the
safe side.
If the main daemon is not notified about a worker finishing an event
the refcounting of the worker struct will be wrong, and we will lose
track of the number of children we have to wait for.
This should not happen, but if it does we better complain loudly about
it. Worst case udev will wait for 30 seconsd at shutdown waiting for
nonexistent workers.
Remove some redundant logging, and reduce the log-level in most cases. The only
case that is really critical is if a worker failed while hanlding an event, so
keep that at error level.
udev uses inotify to implement a scheme where when the user closes
a writable device node, a change uevent is forcefully generated.
In the case of block devices, it actually requests a partition rescan.
This currently can't be synchronized with "udevadm settle", i.e. this
is not reliable in a script:
sfdisk --change-id /dev/sda 1 81
udevadm settle
mount /dev/sda1 /foo
The settle call doesn't synchronize there, so at the same time we try
to mount the device, udevd is busy removing the partition device nodes and
readding them again. The mount call often happens in that moment where the
partition node has been removed but not readded yet.
This exact issue was fixed long ago:
http://git.kernel.org/cgit/linux/hotplug/udev.git/commit/?id=bb38678e3ccc02bcd970ccde3d8166a40edf92d3
but that fix is no longer valid now that sequence numbers are no longer
used.
Fix this by forcing another mainloop iteration after handling inotify events
before unblocking settle. If the inotify event caused us to generate a
"change" event, we'll pick that up in the following loop iteration, before
we reach the end of the loop where we respond to settle's control message,
unblocking it.
