Otherwise we keep collecting stuff from env generators, and we really
shouldn't.
This was working properly on reexec but not on reload, as for reexec we
would always start fresh, but for reload would reuse the Manager object
and hence its default environment set.
Fixes: #10671
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 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
If unit_deserialize() fails (because one read line is overly long), it returns
an error and we would have assumed that the next read would point to the next
unit to deserialize.
But instead unit_deserialize() can leave the file offset in the middle of a
line.
Therefore we need to ignore and skip the current unit in this case too.
While at it, move unit deserialization in a dedicated functions. That should
make the code easier to read.
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.
The predicate function manager_timestamp_shall_serialize() simply says
whether to serialize or not serialize a timestamp, and should make
things a bit easier to read.
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
For example in a container we'd log:
Oct 17 17:01:10 rawhide systemd[1]: Started Power-Off.
Oct 17 17:01:10 rawhide systemd[1]: Forcibly powering off: unit succeeded
Oct 17 17:01:10 rawhide systemd[1]: Reached target Power-Off.
Oct 17 17:01:10 rawhide systemd[1]: Shutting down.
and on the console we'd write (in red)
[ !! ] Forcibly powering off: unit succeeded
This is not useful in any way, and the fact that we're calling an "emergency action"
is an internal implementation detail. Let's log about c-a-d and the watchdog actions
only.
The setting is now only looked at when considering an action for a job timeout
or unit start limit. It is ignored for ctrl-alt-del, SuccessAction, SuccessFailure.
v2: turn the parameter into a flag field
v3: rename Options to Flags
All over the place we define local variables for the various sockopts
that take a bool-like "int" value. Sometimes they are const, sometimes
static, sometimes both, sometimes neither.
Let's clean this up, introduce a common const variable "const_int_one"
(as well as one matching "const_int_zero") and use it everywhere, all
acorss the codebase.
If a memory error occurred, we would still go through the path which sets the
error on ferror(). It is unlikely that ferror() returns true, but it's seems
cleaner to just propagate the error we already have.
The handling of fgets() returning NULL is also simplified: according to the man
page, it returns NULL only on EOF or error. So if feof() returns true, I don't
think we should call ferror() again.
While at it, let's set errno to 0 and check that it is set before returning it
as an error. The man pages for fgets() and feof() do not say anything about
setting errno.
Here the behaviour is nominally changed, because we will decrease the
counter on error. But the only caller quits the program if error occurs,
so this makes no practical difference.
Currently they aren't covered and it probably isn't worth adding another
kind of timestamp just for this, hence simply include it in the regular
generator timestamps.
Let's do so already when we are about to complete startup/reload, so
that manager_catchup() is run in a context where MANAGER_IS_RUNNING()
returns true, as the intention is.
Fixes: #9518
Both functions do partly the same, let's make sure they do it in the
same order, and that we don't miss some calls.
This makes a number of changes:
1. Moves exec_runtime_vacuum() two calls down in manager_startup(). This
should not have any effect but makes manager_startup() more like
manager_reload().
2. Calls manager_recheck_journal(), manager_recheck_dbus(),
manager_enqueue_sync_bus_names() in manager_startup() too. This is a
good idea since during reeexec we pass through manager_startup() and
hence can't assume dbus and journald weren't up yet, hence let's
check if they are ready to be connected to.
3. Include manager_enumerate_perpetual() in manager_reload(), too. This
is not strictly necessary, since these units are included in the
serialization anyway, but it's still a nice thing, in particular as
theoretically the deserialization could fail.
let's clean up error handling and logging in manager_reload() a bit.
Specifically: make sure we log about every error we might encounter at
least and at most once.
When we encounter an error before the "point of no return" then log at
LOG_ERR about it and propagate it. Otherwise, eat it up, but warn about
it and proceed, it's the best we can do.
If manager_serialize() fails in the middle (which it hopefully doesn't)
make sure to fix up m->n_reloading correctly again so that we don't
leave it > 0 when it really shouldn't be.
Let's make them typesafe, and let's add a nice macro helper for checking
if we are in a test run, which should make testing for this much easier
to read for most cases.
Instead of blacklisting when not to trim the cgroup tree, let's instead
whitelist when to do it, as an excercise of being careful when being
destructive.
This should not change behaviour with exception that during switch roots
we now won't attempt to trim the cgroup tree anymore. Which is more
correct behaviour after all we serialize/deserialize during the
transition and should be needlessly destructive.
"ExitCode" is a bit of a misnomer in two ways: it suggests this was
about the "exit code" concept that exit()/waitid() deal with, but really
isn't. Moreover, it's not event just about exiting either, but more
often about reloading/reexecing or rebooting. Let's hence pick a new
name for this that is a bit more correct.
I initially thought about naming this the "state", but that'd be a
misnomer too, as the value really encodes a "goal" more than a current
state. Also we already have the externally visible ManagerState.
No actual changes in behaviour, just the rename.
Previously, we'd act immediately on StopWhenUnneeded= when a unit state
changes. With this rework we'll maintain a queue instead: whenever
there's the chance that StopWhenUneeded= might have an effect we enqueue
the unit, and process it later when we have nothing better to do.
This should make the implementation a bit more reliable, as the unit notify event
cannot immediately enqueue tons of side-effect jobs that might
contradict each other, but we do so only in a strictly ordered fashion,
from the main event loop.
This slightly changes the check when to consider a unit "unneeded".
Previously, we'd assume that a unit in "deactivating" state could also
be cleaned up. With this new logic we'll only consider units unneeded
that are fully up and have no job queued. This means that whenever
there's something pending for a unit we won't clean it up.
Looking at a recent Bad Day, my log contains over 100 lines of
systemd[23895]: Failed to connect to API bus: Connection refused
It is due to "systemd --user" retrying to connect to an API bus.[*] I
would prefer to avoid spamming the logs. I don't think it is good for us
to retry so much like this.
systemd was mislead by something setting DBUS_SESSION_BUS_ADDRESS. My best
guess is an unfortunate series of events caused gdm to set this. gdm has
code to start a session dbus if there is not a bus available already (and
in this case it exports the environment variable). I believe it does not
normally do this when running under systemd, because "systemd --user" and
hence "dbus.service" would already have been started by pam_systemd.
I see two possibilities
1. Rip out the check for DBUS_SESSION_BUS_ADDRESS entirely.
2. Only check for DBUS_SESSION_BUS_ADDRESS on startup. Not in the
"recheck" logic.
The justification for 2), is that the recheck is called from unit_notify(),
this is used to check whether the service just started (or stopped) was
"dbus.service". This reason for rechecking does not apply if we think
the session bus was started outside our logic.
But I think we can justify 1). dbus-daemon ships a statically-enabled
/usr/lib/systemd/user/dbus.service, which would conflict with an attempt to
use an external dbus. Also "systemd --user" is started from user@.service;
if you try to start it manually so that it inherits an environment
variable, it will conflict if user@.service was started by pam_systemd
(or loginctl enable-linger).
We add n_installed_jobs and n_failed_jobs to our inner state after
deserialization. This is fine during daemon-reexec when we start with clear
Manager (and some jobs possibly queued before deserialization), however,
daemon-reload works with the same manager and adding the values would
effectively double the counters. Reset the counters before we deserialize and
add their values again.
These lines are generally out-of-date, incomplete and unnecessary. With
SPDX and git repository much more accurate and fine grained information
about licensing and authorship is available, hence let's drop the
per-file copyright notice. Of course, removing copyright lines of others
is problematic, hence this commit only removes my own lines and leaves
all others untouched. It might be nicer if sooner or later those could
go away too, making git the only and accurate source of authorship
information.
This part of the copyright blurb stems from the GPL use recommendations:
https://www.gnu.org/licenses/gpl-howto.en.html
The concept appears to originate in times where version control was per
file, instead of per tree, and was a way to glue the files together.
Ultimately, we nowadays don't live in that world anymore, and this
information is entirely useless anyway, as people are very welcome to
copy these files into any projects they like, and they shouldn't have to
change bits that are part of our copyright header for that.
hence, let's just get rid of this old cruft, and shorten our codebase a
bit.
To make debugging easier, this patches allows one to change the log target and
do reload/reexec without modifying configuration permanently, which makes
debugging easier.
Indeed if one changed the log target at runtime (via the bus or via signals),
the change was lost on the next reload/reexecution.
In order to restore back the default value (set via system.conf, environment
variables or any other means ), the empty string in the "LogTarget" property is
now supported as well as sending SIGTRMIN+26 signal.
To make debugging easier, this patches allows one to change the log level and
do reload/reexec without modifying configuration permanently, which makes
debugging easier.
Indeed if one changed the log max level at runtime (via the bus or via
signals), the change was lost on the next daemon reload/reexecution.
In order to restore the original value back (set via system.conf, environment
variables or any other means), the empty string in the "LogLevel" property is
now supported as well as sending SIGRTMIN+23 signal.
Previously the enumerate() callback defined for each unit type would do
two things:
1. It would create perpetual units (i.e. -.slice, system.slice, -.mount and
init.scope)
2. It would enumerate units from /proc/self/mountinfo, /proc/swaps and
the udev database
With this change these two parts are split into two seperate methods:
enumerate() now only does #2, while enumerate_perpetual() is responsible
for #1. Why make this change? Well, perpetual units should have a
slightly different effect that those found through enumeration: as
perpetual units should be up unconditionally, perpetually and thus never
change state, they should also not pull in deps by their state changing,
not even when the state is first set to active. Thus, their state is
generally initialized through the per-device coldplug() method in
similar fashion to the deserialized state from a previous run would be
put into place. OTOH units found through regular enumeration should
result in state changes (and thus pull in deps due to state changes),
hence their state should be put in effect in the catchup() method
instead. Hence, given this difference, let's also separate the
functions, so that the rule is:
1. What is created in enumerate_perpetual() should be started in
coldplug()
2. What is created in enumerate() should be started in catchup().
This is very similar to the existing unit method coldplug() but is
called a bit later. The idea is that that coldplug() restores the unit
state from before any prior reload/restart, i.e. puts the deserialized
state in effect. The catchup() call is then called a bit later, to
catch up with the system state for which we missed notifications while
we were reloading. This is only really useful for mount, swap and device
mount points were we should be careful to generate all missing unit
state change events (i.e. call unit_notify() appropriately) for
everything that happened while we were reloading.
It's a bit prettier that day as the function won't silently overwrite
any possibly pre-initialized field, and destroy it right before we
allocate a new event source.
The function is similar to path_kill_slashes() but also removes
initial './', trailing '/.', and '/./' in the path.
When the second argument of path_simplify() is false, then it
behaves as the same as path_kill_slashes(). Hence, this also
replaces path_kill_slashes() with path_simplify().
When "systemctl daemon-reload" is run at the same time as "systemctl
start foo", the latter might hang. That's because commands like start
wait for JobRemoved signal to know when the job is finished. But if the
job is finished during reloading, the signal is never sent.
The hang can be easily reproduced by running
# for ((N=1; N>0; N++)) ; do echo $N ; systemctl daemon-reload ; done
# for ((N=1; N>0; N++)) ; do echo $N ; systemctl start systemd-coredump.socket ; done
in two different terminals. The start command will hang after 1-2
iterations.
This keeps track of jobs that were started before reload and finished
during it and sends JobRemoved after the reload has finished.
We'd write a sequence that was invalid unicode and this caused the d-bus
connection to be terminated:
$ busctl get-property org.freedesktop.systemd1 /org/freedesktop/systemd1/unit/dbus_2esocket org.freedesktop.systemd1.Unit SubState
s "running"
$ busctl get-property org.freedesktop.systemd1 /org/freedesktop/systemd1/unit/dbus_e2socket org.freedesktop.systemd1.Unit SubState
Remote peer disconnected
$ busctl get-property org.freedesktop.systemd1 /org/freedesktop/systemd1/unit/dbus_e2socket org.freedesktop.systemd1.Unit SubState
(hangs)
Fixes#8978.
When I see "test", I have to think three times what the return value
means. With "below" this is immediately clear. ratelimit_below(&limit)
sounds almost like English and is imho immediately obvious.
(I also considered ratelimit_ok, but this strongly implies that being under the
limit is somehow better. Most of the times this is true, but then we use the
ratelimit to detect triple-c-a-d, and "ok" doesn't fit so well there.)
C.f. a1bcaa07.
Previously we were a bit sloppy with the index and size types of arrays,
we'd regularly use unsigned. While I don't think this ever resulted in
real issues I think we should be more careful there and follow a
stricter regime: unless there's a strong reason not to use size_t for
array sizes and indexes, size_t it should be. Any allocations we do
ultimately will use size_t anyway, and converting forth and back between
unsigned and size_t will always be a source of problems.
Note that on 32bit machines "unsigned" and "size_t" are equivalent, and
on 64bit machines our arrays shouldn't grow that large anyway, and if
they do we have a problem, however that kind of overly large allocation
we have protections for usually, but for overflows we do not have that
so much, hence let's add it.
So yeah, it's a story of the current code being already "good enough",
but I think some extra type hygiene is better.
This patch tries to be comprehensive, but it probably isn't and I missed
a few cases. But I guess we can cover that later as we notice it. Among
smaller fixes, this changes:
1. strv_length()' return type becomes size_t
2. the unit file changes array size becomes size_t
3. DNS answer and query array sizes become size_t
Fixes: https://bugs.freedesktop.org/show_bug.cgi?id=76745
Files which are installed as-is (any .service and other unit files, .conf
files, .policy files, etc), are left as is. My assumption is that SPDX
identifiers are not yet that well known, so it's better to retain the
extended header to avoid any doubt.
I also kept any copyright lines. We can probably remove them, but it'd nice to
obtain explicit acks from all involved authors before doing that.
Currently we add target dependencies while we are loading units. This
can create ordering loops even if configuration doesn't contain any
loop. Take for example following configuration,
$ systemctl get-default
multi-user.target
$ cat /etc/systemd/system/test.service
[Unit]
After=default.target
[Service]
ExecStart=/bin/true
[Install]
WantedBy=multi-user.target
If we encounter such unit file early during manager start-up (e.g. load
queue is dispatched while enumerating devices due to SYSTEMD_WANTS in
udev rules) we would add stub unit default.target and we order it Before
test.service. At the same time we add implicit Before to
multi-user.target. Later we merge two units and we create ordering cycle
in the process.
To fix the issue we will now never add any target dependencies until we
loaded all the unit files and resolved all the aliases.
This is similar to TAKE_PTR() but operates on file descriptors, and thus
assigns -1 to the fd parameter after returning it.
Removes 60 lines from our codebase. Pretty good too I think.
Let's better check this inside of the call than before it, so that we
never issue this while reloading, even should these calls be called due
to other reasons than just the unit notify.
This makes sure the reload state is unset a bit earlier in
manager_reload() so that we can safely call this function from there and
they do the right thing.
Follow-up for e63ebf71ed.
When running tests like test-unit-name, there is not point in setting
up the cgroup and signals and interacting with the environment. Similarly
when running fuzz testing of the parser.
Add new MANAGER_TEST_RUN_BASIC which takes the role of MANAGER_TEST_RUN_MINIMAL,
and redefine MANAGER_TEST_RUN_MINIMAL to just create the basic data structures.
