The fix in 8f1751a111 made me wonder if we could automatically detect
when pointers are accessed but when this might not be safe. Systemd
is already using a lot of `assert(dst)` and this change now forces
us to use them.
So this commit (ab)uses coccinelle to flag any pointer parameter
dereference not preceded by assert(param), ASSERT_PTR(param), or an
explicit NULL check. It adds integration into meson as a new "coccinelle"
test suite (just like clang-tidy) and is run in CI. The check is not
perfect but seems a reasonable heuristic.
For this RFC commit it is scoped to a subset, it excludes 25 dirs right
now and includes around 100. About 300 warnings left. Busywork that I am
happy to do if there is agreement that it is worth it.
With this in place we would have caught the bug from 8f1751a111 in CI:
```
FAIL: check-pointer-deref.cocci found issues in systemd/src/boot:
diff -u -p systemd/src/boot/measure.c /tmp/nothing/measure.c
--- systemd/src/boot/measure.c
+++ /tmp/nothing/measure.c
@@ -312,7 +312,6 @@ EFI_STATUS tpm_log_tagged_event(
if (err != EFI_SUCCESS)
return err;
- *ret_measured = true;
return EFI_SUCCESS;
}
```
This also adds a new POINTER_MAY_BE_NULL() for the cases when the
called function will do the NULL check (like `iovec_is_set()`).
We often have a pattern where the same verb function is used for
multiple actions. This leads to an antipattern where we figure out what
action needs to be taken from argv[0] multiple times: often once in
parse_argv() to figure out what options are allowed, then once again
implicitly in dispatch_verb(), and then again in the action verb itself.
Let's allow passing a parameter into the verb to simplify this.
This matches a pattern we have in conf-parser.h, where we have both
void *userdata (more global) and void *data (per-config item). Here,
I opted for uintptr_t userdata. It seems that most of the time we'll
want to just pass an enum value. This works OK with no casts. I also
tried a void* and union. In both cases, much more boilerplate is needed:
either a cast or a macro to help avoid compiler warnings. uintptr_t
seems generic enough to cover foreseeable usecases with no fuss.
This is a noop refactoring. See next commit for an example.
Admittedly, some of our glyphs _are_ special, e.g. "O=" for SPECIAL_GLYPH_TOUCH ;)
But we don't need this in the name. The very long names make some invocations
very wordy, e.g. special_glyph(SPECIAL_GLYPH_SLIGHTLY_UNHAPPY_SMILEY).
Also, I want to add GLYPH_SPACE, which is not special at all.
These operations might require slow I/O, and thus might block PID1's main
loop for an undeterminated amount of time. Instead of performing them
inline, fork a worker process and stash away the D-Bus message, and reply
once we get a SIGCHILD indicating they have completed. That way we don't
break compatibility and callers can continue to rely on the fact that when
they get the method reply the operation either succeeded or failed.
To keep backward compatibility, unlike reload control processes, these
are ran inside init.scope and not the target cgroup. Unlike ExecReload,
this is under our control and is not defined by the unit. This is necessary
because previously the operation also wasn't ran from the target cgroup,
so suddenly forking a copy-on-write copy of pid1 into the target cgroup
will make memory usage spike, and if there is a MemoryMax= or MemoryHigh=
set and the cgroup is already close to the limit, it will cause an OOM
kill, where previously it would have worked fine.
This is a lot of stuff, and sometimes quite wild, let's turn this into
its own header.
All stuff color-related that just generates sequences is now in
ansi-color.h (no .c file!), and everything more complex that
probes/ineracts with terminals remains in termina-util.[ch]
Let's clean up our function naming a bit, and always name the
verb_xyz(), where the xyz maps to the command line verb as closely as
possible.
No actual code changes, just an attempt to make the systemctl sources a
bit more systematic, and less surprising.
This is just some refactoring: shifting around of code, not change in
codeflow.
This splits up the way too huge systemctl.c in multiple more easily
digestable files. It roughly follows the rule that each family of verbs
gets its own .c/.h file pair, and so do all the compat executable names
we support. Plus three extra files for sysv compat (which existed before
already, but I renamed slightly, to get the systemctl- prefix lik
everything else), a -util file with generic stuff everything uses, and a
-logind file with everything that talks directly to logind instead of
PID1.
systemctl is still a bit too complex for my taste, but I think this way
itc omes in a more digestable bits at least.
No change of behaviour, just reshuffling of some code.
Michael Vogt
Zbigniew Jędrzejewski-Szmek
Yu Watanabe
Daan De Meyer
Zbigniew Jędrzejewski-Szmek
Luca Boccassi
Lennart Poettering
David Tardon
Mike Yuan
Jiehong