So far StopWhenUnneeded= handling and UpheldBy= handling was already
processed by a queue that is dispatched in a deferred mode of operation
instead of instantly. This changes BoundBy= handling to be processed the
same way.
This should ensure that all *event*-to-job propagation is done directly
from unit_notify(), while all *state*-to-job propagation is done from a
deferred work queue, quite systematically. The work queue is submitted
to by unit_notify() too.
Key really is the difference between event and state: some jobs shall be
queued one-time on events (think: OnFailure= + OnSuccess= and similar),
others shall be queued continuously when a specific state is in effect
(think: UpheldBy=). The latter cases are usually effect of the
combination of states of a few units (e.g. StopWhenUnneeded= checks
wether any of the Wants=/Requires=/… deps are still up before acting),
and hence it makes sense to trigger them to be run after an individual
unit's state changed, but process them on a queue that runs whenever
there's nothing else to do that ensures the decision on them is only
taken after all jobs/queued IO events are dispatched, and things
settled, so that it makes sense to come to a combined conclusion. If
we'd dispatch this work immediately inside of unit_notify() we'd always
act instantly, even though another event from another unit that is
already queued might make the work unnecessary or invalid.
This is mostly a commit to make things philosophically clean. It does
not add features, but it should make corner cases more robust.
This is like a really strong version of Wants=, that keeps starting the
specified unit if it is ever found inactive.
This is an alternative to Restart= inside a unit, acknowledging the fact
that whether to keep restarting the unit is sometimes not a property of
the unit itself but the state of the system.
This implements a part of what #4263 requests. i.e. there's no
distinction between "always" and "opportunistic". We just dumbly
implement "always" and become active whenever we see no job queued for
an inactive unit that is supposed to be upheld.
$ SYSTEMD_LOG_LEVEL=debug build/systemd --test --user
...
Failed to lookup RuntimeDirectory path: No such device or address <---- this line is new
Failed to allocate manager object: No such device or address
We would fail and only say "Failed to allocate manager object: ENODEV" which is
not entirely self-explanatory. Let's add a better log message.
With some versions of the compiler, the _cleanup_ attr makes it think
the variable might be freed/closed when uninitialized, even though it
cannot happen. The added cost is small enough to be worth the benefit,
and optimized builds will help reduce it even further.
Let's drop unused function arguments, and needless double pointers where
we can.
no actual change in behaviour, just simplifications
(I tried to track down #14026 without success, and this came out of it)
The last release of Upstart was July 2014 [1], and there have been no new
commits to the repo. We should move on too.
[1] https://lists.ubuntu.com/archives/upstart-devel/2014-July/003313.html
The only real support was in the code that looked for $PREVLEVEL.
https://codesearch.debian.net/search?q=PREVLEVEL&literal=1&perpkg=1 shows this
string in our own code (or the copy in elogind), our own man pages, and init
scripts for two packages (brltty, salt), which shouldn't be used with systemd.
(And both *check* for PREVLEVEL, and don't set it. So most likely nothing at
all sets it.)
Apparently SELinux inserts control data into AF_UNIX datagrams where we
don't expect it, thus miscalculating the control data. This looks like
something to fix in SELinux, but we still should handle this gracefully
and just drop the offending datagram and continue.
recvmsg_safe() actually already drops the datagram, it's just a matter
of actually ignoring EXFULL (which it generates if control data is too
large) in the right places.
This does this wherever an AF_UNIX/SOCK_DGRAM socket is used with
recvmsg_safe() that is not just internal communication.
Fixes: #17795
Follow-up for: 3691bcf3c5
When manager_{set|override}_watchdog is called, set the watchdog timeout
regardless of whether the hardware watchdog was successfully initialized. If
the watchdog was requested but could not be initialized, then instead of
pinging it, attempt to initialize it again. This ensures that the hardware
watchdog is initialized even if the kernel module for it isn't loaded when
systemd starts (which is quite likely, unless it is compiled in).
This builds on work by @danc86 in https://github.com/systemd/systemd/pull/17460,
but fixes the issue of not updating the watchdog timeout with the actual value
from the hardware.
Fixes https://github.com/systemd/systemd/issues/17838
Co-authored-by: Dan Callaghan <djc@djc.id.au>
Co-authored-by: Michael Marley <michael@michaelmarley.com>
Instead of assuming that more-recently modified directories have higher mtime,
just look for any mtime changes, up or down. Since we don't want to remember
individual mtimes, hash them to obtain a single value.
This should help us behave properly in the case when the time jumps backwards
during boot: various files might have mtimes that in the future, but we won't
care. This fixes the following scenario:
We have /etc/systemd/system with T1. T1 is initially far in the past.
We have /run/systemd/generator with time T2.
The time is adjusted backwards, so T2 will be always in the future for a while.
Now the user writes new files to /etc/systemd/system, and T1 is updated to T1'.
Nevertheless, T1 < T1' << T2.
We would consider our cache to be up-to-date, falsely.
This check was added in d904afc730. It would only
apply in the case where the cache hasn't been loaded yet. I think we pretty
much always have the cache loaded when we reach this point, but even if we
didn't, it seems better to try to reload the unit. So let's drop this check.
We really only care if the cache has been reloaded between the time when we
last attempted to load this unit and now. So instead of recording the actual
time we try to load the unit, just store the timestamp of the cache. This has
the advantage that we'll notice if the cache mtime jumps forward or backward.
Also rename fragment_loadtime to fragment_not_found_time. It only gets set when
we failed to load the unit and the old name was suggesting it is always set.
In https://bugzilla.redhat.com/show_bug.cgi?id=1871327
(and most likely https://bugzilla.redhat.com/show_bug.cgi?id=1867930
and most likely https://bugzilla.redhat.com/show_bug.cgi?id=1872068) we try
to load a non-existent unit over and over from transaction_add_job_and_dependencies().
My understanding is that the clock was in the future during inital boot,
so cache_mtime is always in the future (since we don't touch the fs after initial boot),
so no matter how many times we try to load the unit and set
fragment_loadtime / fragment_not_found_time, it is always higher than cache_mtime,
so manager_unit_cache_should_retry_load() always returns true.
The name is misleading, since we aren't really loading the unit from cache — if
this function returns true, we'll try to load the unit from disk, updating the
cache in the process.
Similarly to "setup" vs. "set up", "fallback" is a noun, and "fall back"
is the verb. (This is pretty clear when we construct a sentence in the
present continous: "we are falling back" not "we are fallbacking").
Read-only /var/tmp is more likely, because it's backed by a real device. /tmp
is (by default) backed by tmpfs, but it doesn't have to be. In both cases the
same consideration applies.
If we boot with read-only /var/tmp, any unit with PrivateTmp=yes would fail
because we cannot create the subdir under /var/tmp to mount the private directory.
But many services actually don't require /var/tmp (either because they only use
it occasionally, or because they only use /tmp, or even because they don't use the
temporary directories at all, and PrivateTmp=yes is used to isolate them from
the rest of the system).
To handle both cases let's create a read-only directory under /run/systemd and
mount it as the private /tmp or /var/tmp. (Read-only to not fool the service into
dumping too much data in /run.)
$ sudo systemd-run -t -p PrivateTmp=yes bash
Running as unit: run-u14.service
Press ^] three times within 1s to disconnect TTY.
[root@workstation /]# ls -l /tmp/
total 0
[root@workstation /]# ls -l /var/tmp/
total 0
[root@workstation /]# touch /tmp/f
[root@workstation /]# touch /var/tmp/f
touch: cannot touch '/var/tmp/f': Read-only file system
This commit has more changes than I like to put in one commit, but it's touching all
the same paths so it's hard to split.
exec_runtime_make() was using the wrong cleanup function, so the directory would be
left behind on error.
When a command asks to load a unit directly and it is in state
UNIT_NOT_FOUND, and the cache is outdated, we refresh it and
attempto to load again.
Use the same logic when building up a transaction and a dependency in
UNIT_NOT_FOUND state is encountered.
Update the unit test to exercise this code path.
When the system is under heavy load, it can happen that the unit cache
is refreshed for an unrelated reason (in the test I simulate this by
attempting to start a non-existing unit). The new unit is found and
accounted for in the cache, but it's ignored since we are loading
something else.
When we actually look for it, by attempting to start it, the cache is
up to date so no refresh happens, and starting fails although we have
it loaded in the cache.
When the unit state is set to UNIT_NOT_FOUND, mark the timestamp in
u->fragment_loadtime. Then when attempting to load again we can check
both if the cache itself needs a refresh, OR if it was refreshed AFTER
the last failed attempt that resulted in the state being
UNIT_NOT_FOUND.
Update the test so that this issue reproduces more often.
Patch contains a coccinelle script, but it only works in some cases. Many
parts were converted by hand.
Note: I did not fix errors in return value handing. This will be done separate
to keep the patch comprehensible. No functional change is intended in this
patch.
