Taking a stab at implementing #14479.
Add {Condition,Assert}CPUFeature to `systemd-analyze` & friends. Implement it
by executing the CPUID instruction. Add tables for common x86/i386
features.
Tested via unit tests + checked that commands such as:
```bash
systemd-analyze condition 'AssertCPUFeature = rdrand'
```
Succeed as expected and that commands such as
```bash
systemd-analyze condition 'AssertCPUFeature = foobar'
```
Fail as expected. Finally, I have amended the `systemd.unit` manual page
with the new condition and the list of all currently supported flags.
Use the right FD, and do a fd_reopen instead of a dup, since the
latter will still share the internal pointer which then gets
moved by FOREACH_DIRENT, affecting the caller's FD.
If the cleanup function returns the appropriate type, use that to reset the
variable. For other functions (usually the foreign ones which return void), add
an explicit value to reset to.
This causes a bit of code churn, but I think it might be worth it. In a
following patch static destructors will be called from a fuzzer, and this
change allows them to be called multiple times. But I think such a change might
help with detecting unitialized code reuse too. We hit various bugs like this,
and things are more obvious when a pointer has been set to NULL.
I was worried whether this change increases text size, but it doesn't seem to:
-Dbuildtype=debug:
before "tree-wide: return NULL from freeing functions":
-rwxrwxr-x 1 zbyszek zbyszek 4117672 Feb 16 14:36 build/libsystemd.so.0.30.0*
-rwxrwxr-x 1 zbyszek zbyszek 4494520 Feb 16 15:06 build/systemd*
after "tree-wide: return NULL from freeing functions":
-rwxrwxr-x 1 zbyszek zbyszek 4117672 Feb 16 14:36 build/libsystemd.so.0.30.0*
-rwxrwxr-x 1 zbyszek zbyszek 4494576 Feb 16 15:10 build/systemd*
now:
-rwxrwxr-x 1 zbyszek zbyszek 4117672 Feb 16 14:36 build/libsystemd.so.0.30.0*
-rwxrwxr-x 1 zbyszek zbyszek 4494640 Feb 16 15:15 build/systemd*
-Dbuildtype=release:
before "tree-wide: return NULL from freeing functions":
-rwxrwxr-x 1 zbyszek zbyszek 5252256 Feb 14 14:47 build-rawhide/libsystemd.so.0.30.0*
-rwxrwxr-x 1 zbyszek zbyszek 1834184 Feb 16 15:09 build-rawhide/systemd*
after "tree-wide: return NULL from freeing functions":
-rwxrwxr-x 1 zbyszek zbyszek 5252256 Feb 14 14:47 build-rawhide/libsystemd.so.0.30.0*
-rwxrwxr-x 1 zbyszek zbyszek 1834184 Feb 16 15:10 build-rawhide/systemd*
now:
-rwxrwxr-x 1 zbyszek zbyszek 5252256 Feb 14 14:47 build-rawhide/libsystemd.so.0.30.0*
-rwxrwxr-x 1 zbyszek zbyszek 1834184 Feb 16 15:16 build-rawhide/systemd*
I would expect that the compiler would be able to elide the setting of a
variable if the variable is never used again. And this seems to be the case:
in optimized builds there is no change in size whatsoever. And the change in
size in unoptimized build is negligible.
Something strange is happening with size of libsystemd: it's bigger in
optimized builds. Something to figure out, but unrelated to this patch.
I started working on this because I wanted to change how
DEFINE_TRIVIAL_CLEANUP_FUNC is defined. Even independently of that change, it's
nice to make make things more consistent and predictable.
All callers of strv_env_replace() would free the argument on error.
So let's follow the same pattern as with strv_consume (and similar
naming) and unconditionally "use up" the argument.
Numeric ifnames should be acceptable only if that's enabled by flag, and
refused otherwise. Hence, let's parse as ifindex first, and if that
works decide. Finally, let's refuse any numeric ifnames that are not
valid ifindexs, but look like them.
The property is never set by systemd, only reset after a stop or restart or
reload. It may externally be set to mark the unit for a later restart/reload.
I wasn't sure whether to configure the property only for the types where this
makes sense (Service, Swap, etc). But Restart() method is defined on the unit,
and also having this always under the same property name is more convenient.
The general idea is that when a unit file is "linked" (i.e. installed by
symlinking from outside of the search paths), the *destination* name is
irrelevant. It doesn't even have to be a valid unit name, or to match the type
or instance value. The obvious collorary is that we shouldn't look at the
symlink destination name to derive the unit name, instance value, or anything
else at all.
When building the name map, when we find a linked unit (possibly at the end
of a series of alias redirects), store the *source* of the final symlink as the
fragment path. This has two effects:
- we stop looking at the *target* file name to derive unit info, i.e. actually
implement the stuff described in the first paragraph.
- we load the unit fragment through the symlink. If someone were to remove the
symlink, we'll not load the unit. This seems like the right thing.
Fixes#18058.
Before this change, we were generally quite confused about unit alises for
linked units. Fortunately most poeple use the same symlink source and target,
so in practice we wouldn't hit this too often.
In unit_load_fragment() a comment is added to explain what we're doing there.
Docker doesn't set $container, so it cannot be detected that way. Instead, we
check for presence of /.dockerinit, which it creates. Podman does set
$container, but some Red Hat images (in particular, Fedora images) override
$container to equal "oci". So to correctly detect Podman containers, we check
for presence of /run/.containerenv, which is created by Podman and is now the
official way to get information about the container from within the container.
Fixes https://github.com/systemd/systemd/issues/15393
We'd return -1 (-EPERM), even though we have a general rule to use real errno
values. The particular case that caught my attention was:
$ sudo udevadm control -l asdf
Failed to parse log priority 'asdf': Operation not permitted
... but "git grep 'r =.*_from_string' src/" return 110 hits. Confusingly, some
of the _from_string functions already return a proper errno value, so not all
of those are broken, but probably quite a few.
As suggested in https://github.com/systemd/systemd/pull/11484#issuecomment-775288617.
This does not touch anything exposed in src/systemd. Changing the defines there
would be a compatibility break.
Note that tests are broken after this commit. They will be fixed in the next one.
There may be situations where a cgroup should be protected from killing
or deprioritized as a candidate. In FB oomd xattrs are used to bias oomd
away from supervisor cgroups and towards worker cgroups in container
tasks. On desktops this can be used to protect important units with
unpredictable resource consumption.
The patch allows systemd-oomd to understand 2 xattrs:
"user.oomd_avoid" and "user.oomd_omit". If systemd-oomd sees these
xattrs set to 1 on a candidate cgroup (i.e. while attempting to kill something)
AND the cgroup is owned by root, it will either deprioritize the cgroup as
a candidate (avoid) or remove it completely as a candidate (omit).
Usage is restricted to root owned cgroups to prevent situations where an
unprivileged user can set their own cgroups lower in the kill priority than
another user's (and prevent them from omitting their units from
systemd-oomd killing).
