Some PIDs can remain in the watched list even though their processes have
exited since a long time. It can easily happen if the main process of a forking
service manages to spawn a child before the control process exits for example.
However when a pid is about to be mapped to a unit by calling unit_watch_pid(),
the caller usually knows if the pid should belong to this unit exclusively: if
we just forked() off a child, then we can be sure that its PID is otherwise
unused. In this case we take this opportunity to remove any stalled PIDs from
the watched process list.
If we learnt about a PID in any other form (for example via PID file, via
searching, MAINPID= and so on), then we can't assume anything.
The function so far always returned -ECANCELLED, which is ignored in all
cases the function is invoked, except one: in unit_test_start_limit()
where -ECANCELLED is returned when the start limit is hit, which is part
of unit_start()'s protocol of return values.
Since the emergency_action() logic should be relatively generic and is
used in many places, let's drop the return value from it, since it's
constant anyway, and in alll cases useless. Instead, let's return it in
unit_test_start_limit(), where it's part of the protocol.
No change in behaviour.
Let's add a safety precaution: if the start condition checks for a unit
are tested too often and fail each time, let's rate limit this too.
This should add extra safety in case people define .path, .timer or
.automount units that trigger a service that as a conditoin that always
fails.
Just some renaming, no change in behaviour.
Background: I'd like to add more functions unit_test_xyz() that test
various things, hence let's streamline the naming a bit.
unit_require_mounts_for may be passed path arguments that contain "."
components like for user's home directories where "." is sometimes used
to specify some form of anchor point.
This change stops considering such path as an error and removes the "."
components instead.
Closes: #11910
KillMode=mixed and control group are used to indicate that all
process should be killed off. SendSIGKILL is used for services
that require a clean shutdown. These are typically database
service where a SigKilled process would result in a lengthy
recovery and who's shutdown or startup time is quite variable
(so Timeout settings aren't of use).
Here we take these two factors and refuse to start a service if
there are existing processes within a control group. Databases,
while generally having some protection against multiple instances
running, lets not stress the rigor of these. Also ExecStartPre
parts of the service aren't as rigoriously written to protect
against against multiple use.
closes#8630
Fixes: #11499
Let's return -EAGAIN so that on state change, unit_process_job tries to
add our job to run_queue again so that all the reloads that coalesced
into the installed reload (which itself merged into a running one)
inititally atleast runs *once*. This should ensure service picks up all
config changes reliably.
See the issue being fixed for a detailed explanation.
It would be very wrong if any of the specfier printf calls modified
any of the objects or data being printed. Let's mark all arguments as const
(primarily to make it easier for the reader to see where modifications cannot
occur).
Previously, we'd immediately propagate unit state changes into any jobs
pending for them, always. With this we only do this if the manager is
out of the "reload" state. This fixes the problem #8803 tried to
address, by simply not completing jobs until after the reload (and thus
reestablishment of the dbus connection) is complete.
Note that there's no need to later on explicitly catch up with the
missed job state changes (i.e. there's no need to call
unit_process_job() later one explicitly). That's because for jobs in
JOB_WAITING state on deserialization all jobs are requeued into the run
queue anyway, and thus checked again if they can complete now. And for
JOB_RUNNING jobs unit_catchup() phase is going to trigger missed out
state changes *after* the reload complete anyway (after all that's what
distinguishes from unit_coldplug()).
Replaces: #8803
Let's add a helper call unit_deserialize_job() for this purpose, and
let's move registration in the global jobs hash table into
job_install_deserialized() so that it it is done after all superficial
checks are done, and before transitioning into installed states, so that
rollback code is not necessary anymore.
This splits out a bunch of functions from fileio.c that have to do with
temporary files. Simply to make the header files a bit shorter, and to
group things more nicely.
No code changes, just some rearranging of source files.
Previously, we'd enqueue a unit to the dbus queue whenever the state
changed, after we processed the state change fully. This commit to the
beginning of the state change. This has the benefit that when the state
change causes a job to complete the unit is already in the dbus queue,
and thus we get the guarantee that any unit change can be sent out to
clients before the job change.
Let's inform the clients about assert/condition property changes as they
happen, it's basically for free because assert/condition property
changes generally coincide with other unit state changes (after all
these checks are done on unit_start())
add new "systemd-run-generator" for running arbitrary commands from the kernel command line as system services using the "systemd.run=" kernel command line switch
This adds SuccessActionExitStatus= and FailureActionExitStatus= that may
be used to configure the exit status to propagate in when
SuccessAction=exit or FailureAction=exit is used.
When not specified let's also propagate the exit status of the main
process we fork off for the unit.
Let's highlight the unit description string in the status updates, to
separate them a bit more the english sentence they are part of, and thus
make the different casing less surprising.
This way we can corectly ensure that when a unit that requires some
controller goes away, we propagate the removal of it all the way up, so
that the controller is turned off in all the parents too.
Previously we tried to be smart: when a new unit appeared and it only
added controllers to the cgroup mask we'd update the cached members mask
in all parents by ORing in the controller flags in their cached values.
Unfortunately this was quite broken, as we missed some conditions when
this cache had to be reset (for example, when a unit got unloaded),
moreover the optimization doesn't work when a controller is removed
anyway (as in that case there's no other way for the parent to iterate
though all children if any other, remaining child unit still needs it).
Hence, let's simplify the logic substantially: instead of updating the
cache on the right events (which we didn't get right), let's simply
invalidate the cache, and generate it lazily when we encounter it later.
This should actually result in better behaviour as we don't have to
calculate the new members mask for a whole subtree whever we have the
suspicion something changed, but can delay it to the point where we
actually need the members mask.
This allows us to simplify things quite a bit, which is good, since
validating this cache for correctness is hard enough.
Fixes: #9512
Ideally we'd even propagate this all the way to the client, by having a
separate JobType enum value for this. But it's hard to add this without
breaking compat, hence for now let's at least internally propagate this
case differently from the case "already on it".
This is then used to call job_finish_and_invalidate() slightly
differently, with the already= parameter false, as in the failed
condition case no message was likely produced so far.
This call is only used by job.c and very specific to job handling.
Moreover the very similar logic of job_emit_status_message() is already
in job.c.
Hence, let's clean this up, and move both sets of functions to job.c,
and rename them a bit so that they express precisely what they do:
1. unit_status_emit_starting_stopping_reloading() →
job_emit_begin_status_message()
2. job_emit_status_message() → job_emit_done_status_message()
The first call is after all what we call when we begin with the
execution of a job, and the second call what we call when we are done
wiht it.
Just some moving and renaming, not other changes, and hence no change in
behaviour.
Add unit name in StartLimitAction=, FailureAction= and SuccessAction=
emergency_action() reason messages, so that the problematic unit is
easily visible, for example:
"unit dbus.service failed"
This splits the "environment" field of Manager into two:
transient_environment and client_environment. The former is generated
from configuration file, kernel cmdline, environment generators. The
latter is the one the user can control with "systemctl set-environment"
and similar.
Both sets are merged transparently whenever needed. Separating the two
sets has the benefit that we can safely flush out the former while
keeping the latter during daemon reload cycles, so that env var settings
from env generators or configuration files do not accumulate, but
dynamic API changes are kept around.
Note that this change is not entirely transparent to users: if the user
first uses "set-environment" to override a transient variable, and then
uses "unset-environment" to unset it again things will revert to the
original transient variable now, while previously the variable was fully
removed. This change in behaviour should not matter too much though I
figure.
Fixes: #9972
Let's be more careful with what we serialize: let's ensure we never
serialize strings that are longer than LONG_LINE_MAX, so that we know we
can read them back with read_line(…, LONG_LINE_MAX, …) safely.
In order to implement this all serialization functions are move to
serialize.[ch], and internally will do line size checks. We'd rather
skip a serialization line (with a loud warning) than write an overly
long line out. Of course, this is just a second level protection, after
all the data we serialize shouldn't be this long in the first place.
While we are at it also clean up logging: while serializing make sure to
always log about errors immediately. Also, (void)ify all calls we don't
expect errors in (or catch errors as part of the general
fflush_and_check() at the end.
This should be much better than fgets(), as we can read substantially
longer lines and overly long lines result in proper errors.
Fixes a vulnerability discovered by Jann Horn at Google.
CVE-2018-15686
LP: #1796402https://bugzilla.redhat.com/show_bug.cgi?id=1639071
Don't add an implicit RequiresMountsFor depenency for the
WorkingDirectory of a unit if the "-" character was used to
indicate that "a missing working directory is not considered fatal"
(see systemd.exec(5)). Otherwise systemd might fail the unit
because of missing dependencies.
