This reworks the logic introduced in
a5cede8c24 (#13693).
First of all, let's move this out of util.c, since only PID 1 really
needs this, and there's no real need to have it in util.c.
Then, fix freeing of the variable. It previously relied on
STATIC_DESTRUCTOR_REGISTER() which however relies on static_destruct()
to be called explicitly. Currently only the main-func.h macros do that,
and PID 1 does not. (It might be worth investigating whether to do that,
but it's not trivial.) Hence the freeing wasn't applied.
Finally, an OOM check was missing, add it in.
PID1 may modified the environment passed by the kernel when it starts
running. Commit 9d48671c62 unset $HOME for
example.
In case PID1 is going to switch to a new root and execute a new system manager
which is not systemd, we should restore the original environment as the new
manager might expect some variables to be set by default (more specifically
$HOME).
We have the problem that many early boot or late shutdown issues are harder
to solve than they could be because we have no logs. When journald is not
running, messages are redirected to /dev/kmsg. It is also the time when many
things happen in a rapid succession, so we tend to hit the kernel printk
ratelimit fairly reliably. The end result is that we get no logs from the time
where they would be most useful. Thus let's disable the kernels ratelimit.
Once the system is up and running, the ratelimit is not a problem. But during
normal runtime, things also log to journald, and not to /dev/kmsg, so the
ratelimit is not useful. Hence, there doesn't seem to be much point in trying
to restore the ratelimit after boot is finished and journald is up and running.
See kernel's commit 750afe7babd117daabebf4855da18e4418ea845e for the
description of the kenrel interface. Our setting has lower precedence than
explicit configuration on the kenrel command line.
I was debugging stuff during early boot, and was confused that I never
found the logs for it in kmsg. The reason for that was that /proc is
generally not mounted the first time we do log_open() and hence
log_set_target(LOG_TARGET_KMSG) we do when running as PID 1 had not
effect. A lot later during start-up we call log_open() again where this
is fixed (after the point where we close all remaining fds still open),
but in the meantime no logs every got written to kmsg. This patch fixes
that.
This option is only used on reboot, not on other types of shutdown
modes, so it is misleading.
Keep the old name working for backward compatibility, but remove it
from the documentation.
Rather than always enabling the shutdown WD on kexec, which might be
dangerous in case the kernel driver and/or the hardware implementation
does not reset the wd on kexec, add a new timer, disabled by default,
to let users optionally enable the shutdown WD on kexec separately
from the runtime and reboot ones. Advise in the documentation to
also use the runtime WD in conjunction with it.
Fixes: a637d0f9ec ("core: set shutdown watchdog on kexec too")
At the moment the shutdown watchdog is set only when rebooting.
The set of "things that can go wrong" is not too far off when kexec'ing
and in fact we have a use case where it would be useful - moving to a
new kernel image.
Commit fb39af4ce4 forgot to restore the default
rlimit values (RLIMIT_NOFILE and RLIMIT_MEMLOCK) while PID1 is reloading.
This patch extracts the code in charge of initializing the default values for
those rlimits in order to create dedicated functions, which take care of their
initialization.
These functions are then called in parse_configuration() so we make sure that
the default values for these rlimits get restored every time PID1 is reloading
its configuration.
Make possible to set NUMA allocation policy for manager. Manager's
policy is by default inherited to all forked off processes. However, it
is possible to override the policy on per-service basis. Currently we
support, these policies: default, prefer, bind, interleave, local.
See man 2 set_mempolicy for details on each policy.
Overall NUMA policy actually consists of two parts. Policy itself and
bitmask representing NUMA nodes where is policy effective. Node mask can
be specified using related option, NUMAMask. Default mask can be
overwritten on per-service level.
Since kernel 5.2 the kernel thankfully returns proper errors when we
write a value out of range to the sysctl. Which however breaks writing
ULONG_MAX to request the maximum value. Hence let's write the new
maximum value instead, LONG_MAX.
/cc @brauner
Fixes: #12803
If we had a configuration setting from a configuration file, and it was
removed, we'd still remember the old value, because there's was no mechanism to
"reset" everything, just to assign new values.
Note that the effect of this is limited. For settings that have an "ongoing" effect,
like systemd.confirm_spawn, the new value is simply used. But some settings can only
be set at start.
In particular, CPUAffinity= will be updated if set to a new value, but if
CPUAffinity= is fully removed, it will not be reset, simply because we don't
know what to reset it to. We might have inherited a setting, or we might have
set it ourselves. In principle we could remember the "original" value that was
set when we were executed, but propagate this over reloads and reexecs, but
that would be a lot of work for little gain. So this corner case of removal of
CPUAffinity= is not handled fully, and a reboot is needed to execute the
change. As a work-around, a full mask of CPUAffinity=0-8191 can be specified.
We have settings which may be set on the kernel command line, and also
in /proc/cmdline (for pid1). The settings in /proc/cmdline have higher priority
of course. When a reload was done, we'd reload just the configuration file,
losing the overrides.
So read /proc/cmdline again during reload.
Also, when initially reading the configuration file when program starts,
don't treat any errors as fatal. The configuration done in there doesn't
seem important enough to refuse boot.
This makes the handling of this option match what we do in unit files. I think
consistency is important here. (As it happens, it is the only option in
system.conf that is "non-atomic", i.e. where there's a list of things which can
be split over multiple assignments. All other options are single-valued, so
there's no issue of how to handle multiple assignments.)
The CPU_SET_S api is pretty bad. In particular, it has a parameter for the size
of the array, but operations which take two (CPU_EQUAL_S) or even three arrays
(CPU_{AND,OR,XOR}_S) still take just one size. This means that all arrays must
be of the same size, or buffer overruns will occur. This is exactly what our
code would do, if it received an array of unexpected size over the network.
("Unexpected" here means anything different from what cpu_set_malloc() detects
as the "right" size.)
Let's rework this, and store the size in bytes of the allocated storage area.
The code will now parse any number up to 8191, independently of what the current
kernel supports. This matches the kernel maximum setting for any architecture,
to make things more portable.
Fixes#12605.
When shooting down a service with SIGABRT the user might want to have a
much longer stop timeout than on regular stops/shutdowns. Especially in
the face of short stop timeouts the time might not be sufficient to
write huge core dumps before the service is killed.
This commit adds a dedicated (Default)TimeoutAbortSec= timer that is
used when stopping a service via SIGABRT. In all other cases the
existing TimeoutStopSec= is used. The timer value is unset by default
to skip the special handling and use TimeoutStopSec= for state
'stop-watchdog' to keep the old behaviour.
If the service is in state 'stop-watchdog' and the service should be
stopped explicitly we still go to 'stop-sigterm' and re-apply the usual
TimeoutStopSec= timeout.
This adds a new per-service OOMPolicy= (along with a global
DefaultOOMPolicy=) that controls what to do if a process of the service
is killed by the kernel's OOM killer. It has three different values:
"continue" (old behaviour), "stop" (terminate the service), "kill" (let
the kernel kill all the service's processes).
On top of that, track OOM killer events per unit: generate a per-unit
structured, recognizable log message when we see an OOM killer event,
and put the service in a failure state if an OOM killer event was seen
and the selected policy was not "continue". A new "result" is defined
for this case: "oom-kill".
All of this relies on new cgroupv2 kernel functionality: the
"memory.events" notification interface and the "memory.oom.group"
attribute (which makes the kernel kill all cgroup processes
automatically).
Initially, the check was that /usr is not a separate fs, and was later relaxed
to allow /usr to be mounted in the initramfs. Documentation was updated in 9e93f6f092,
but this comment wasn't. Let's update it too.
When we synthesize a "struct rlimit" structure to pass on for
RLIMIT_NOFILE to our children, let's explicitly make sure that the soft
limit is not above FD_SETSIZE, for compat reason with select().
Note this only applies when we derive the "struct rlimit" from what we
inherited. If the user configures something explicitly it always takes
precedence.
$ build/systemctl --version
systemd 239-3555-g6178cbb5b5
+PAM +AUDIT +SELINUX +IMA -APPARMOR +SMACK +SYSVINIT +UTMP +LIBCRYPTSETUP +GCRYPT +GNUTLS +ACL +XZ +LZ4 +SECCOMP +BLKID +ELFUTILS +KMOD -IDN2 +IDN +PCRE2 default-hierarchy=hybrid
$ git tag v240 -m 'v240'
$ ninja -C build
ninja: Entering directory `build'
[76/76] Linking target fuzz-unit-file.
$ build/systemctl --version
systemd 240
+PAM +AUDIT +SELINUX +IMA -APPARMOR +SMACK +SYSVINIT +UTMP +LIBCRYPTSETUP +GCRYPT +GNUTLS +ACL +XZ +LZ4 +SECCOMP +BLKID +ELFUTILS +KMOD -IDN2 +IDN +PCRE2 default-hierarchy=hybrid
This is very useful during development, because a precise version string is
embedded in the build product and displayed during boot, so we don't have to
guess answers for questions like "did I just boot the latest version or the one
from before?".
This change creates an overhead for "noop" builds. On my laptop, 'ninja -C
build' that does nothing goes from 0.1 to 0.5 s. It would be nice to avoid
this, but I think that <1 s is still acceptable.
Fixes#7183.
PACKAGE_VERSION is renamed to GIT_VERSION, to make it obvious that this is the
more dynamically changing version string.
Why save to a file? It would be easy to generate the version tag using
run_command(), but we want to go through a file so that stuff gets rebuilt when
this file changes. If we just defined an variable in meson, ninja wouldn't know
it needs to rebuild things.
PACKAGE_VERSION is more explicit, and also, we don't pretend that changing the
project name in meson.build has any real effect. "systemd" is embedded in a
thousand different places, so let's just use the hardcoded string consistently.
This is mostly in preparation for future changes.
Whenever we invoke external, foreign code from code that has
RLIMIT_NOFILE's soft limit bumped to high values, revert it to 1024
first. This is a safety precaution for compatibility with programs using
select() which cannot operate with fds > 1024.
This commit adds the call to rlimit_nofile_safe() to all invocations of
exec{v,ve,l}() and friends that either are in code that we know runs
with RLIMIT_NOFILE bumped up (which is PID 1 and all journal code for
starters) or that is part of shared code that might end up there.
The calls are placed as early as we can in processes invoking a flavour
of execve(), but after the last time we do fd manipulations, so that we
can still take benefit of the high fd limits for that.
