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Turns out Coccinelle can handle compound literals just fine, the parsing
errors were caused by incorrectly parsed macros in code before the
literals, so let's just provide simplified versions for such macros.
The parsing error in `Type *foo[ELEMENTSOF(bar)] = {};` is actually
harmless; it occurs only when creating an array of pointers for a type
that's in an external header and it occurs only on the first parser's
pass, subsequent passes resolve the type correctly.
Also, unset ENABLE_DEBUG_HASHMAP, so Coccinelle doesn't expand the
hashmap debug macros.
As for the remaining FIXMEs, I opened a couple of issues in the
Coccinelle upstream to see if they can be fixed there (or at least
properly analyzed).
Turns out I _really_ underestimated the impact of
--include-headers-for-types, as it significantly reduces both runtime
and storage penalties. For example, on my machine the runtime of
uncached run goes down from ~15 minutes to ~2 minutes, and similarly the
total storage needed by the cache goes from ~15 GiB down to ~3 GiB.
Drop the original macro file, since it's not needed anymore thanks to
resolving includes properly, but introduce a similar file -
parsing_hacks.h - that helps Coccinelle in some specific corner cases.
This eliminates most of the outstanding parsing errors in source files.
The remaining ones are limitations of the parsing engine (see the FIXMEs
in pasing_hacks.h) and need further investigation.
Since Coccinelle is originally a kernel tool, it doesn't search the
system include path by default for header files. Without this we're
missing a lot of types provides by stdlib (and other libraries we make
use of).
Turns out that the original way we did things was quite broken, as it
skipped a _lot_ of code. This was because we just threw everything into
one pile and tried to spatch it, but this made Coccinelle sad, like when
man page examples redefined some of our macros, causing typedef
conflicts.
For example, with a minimal reproducer that defines a cleanup macro in
two source files, Coccinelle has no issues when spatch-ing each one
separately:
$ spatch --verbose-parsing --sp-file zz-drop-braces.cocci main.c
init_defs_builtins: /usr/lib64/coccinelle/standard.h
HANDLING: main.c
SPECIAL NAMES: adding _cleanup_ as a attribute with arguments
SPECIAL NAMES: adding _cleanup_free_ as a attribute
$ spatch --verbose-parsing --sp-file zz-drop-braces.cocci
logcontrol-example.c
init_defs_builtins: /usr/lib64/coccinelle/standard.h
HANDLING: logcontrol-example.c
SPECIAL NAMES: adding _cleanup_ as a attribute with arguments
But when you try to spatch both of them at once, Coccinelle starts
complaining and skipping the "bad" code:
$ spatch --verbose-parsing --sp-file zz-drop-braces.cocci main.c logcontrol-example.c
init_defs_builtins: /usr/lib64/coccinelle/standard.h
HANDLING: main.c logcontrol-example.c
SPECIAL NAMES: adding _cleanup_ as a attribute with arguments
SPECIAL NAMES: adding _cleanup_free_ as a attribute
remapping: _cleanup_ to an ident in macro name
ERROR-RECOV: found sync end of #define, line 44
parsing pass2: try again
ERROR-RECOV: found sync end of #define, line 44
parse error
= File "logcontrol-example.c", line 44, column 21, charpos = 1719
around = '__attribute__',
whole content = #define _cleanup_(f) __attribute__((cleanup(f)))
badcount: 2
bad: #include <systemd/sd-journal.h>
bad:
BAD:!!!!! #define _cleanup_(f) __attribute__((cleanup(f)))
This was, unfortunately, hidden as it is visible only with
--verbose-parsing (or --parse-error-msg).
Another issue was how we handled includes. The original way of throwing
them into the pile of source files doesn't really work, leading up to
similar issues as above. The better way is to let Coccinelle properly
resolve all includes by telling it where to find our own include files
(basically the same thing we already do during compilation).
After fixing all this, Coccinelle now has a chance to process much more
of our code (there are still some issues in more complex macros, but
that requires further investigation). However, there's a huge downside
from all of this - doing a _proper_ code analysis is surprisingly time
and resource heavy; meaning that processing just one Coccinelle rule now
takes 15 - 30 minutes.
To make this slightly less painful, Coccinelle supports caching the
generated ASTs, which actually helps a lot - it gets the runtime of one
rule from 15 - 30 minutes down to ~1 minute. It, of course, has its own
downside - the cache is _really_ big (ATTOW the cache takes ~15 GiB).
However, even with the aggressive AST caching you're still looking at
~1 hour for one full Coccinelle run, which is a bit annoying, but I
guess that's the price of doing things _properly_ (but I'll definitely
look into ways of further optimizing this).
As the result is a bit funky (but still valid), i.e.:
static inline void iovec_done_erase(struct iovec *iovec) {
assert(iovec);
- iovec->iov_base = erase_and_free(iovec->iov_base);
- iovec->iov_len = 0;
+ *iovec = IOVEC_MAKE(erase_and_free(iovec->iov_base), 0);
}
Since the empty_to_null() function was "macrofied", we need to use a bit
of black magic to make Coccinelle avoid running the transformation on
the macro itself.
Follow-up to ef2409cbde.
-1 was used everywhere, but -EBADF or -EBADFD started being used in various
places. Let's make things consistent in the new style.
Note that there are two candidates:
EBADF 9 Bad file descriptor
EBADFD 77 File descriptor in bad state
Since we're initializating the fd, we're just assigning a value that means
"no fd yet", so it's just a bad file descriptor, and the first errno fits
better. If instead we had a valid file descriptor that became invalid because
of some operation or state change, the other errno would fit better.
In some places, initialization is dropped if unnecessary.
RUN_WITH_UMASK was initially conceived for spawning externals progs with the
umask set. But nowadays we use it various syscalls and stuff that doesn't "run"
anything, so the "RUN_" prefix has outlived its usefulness.
This was a trivial wrapper that didn't provide any added value. With more
complicated structures like strvs, hashmaps, sets, and arrays, it is possible
to have an empty container. But in case of a list, the list is empty only when
the head is missing.
Also, we generally want the positive condition, so we replace many
if (!LIST_IS_EMPTY(x)) with just if (x).
Let's define two helpers strdupa_safe() + strndupa_safe() which do the
same as their non-safe counterparts, except that they abort if called
with allocations larger than ALLOCA_MAX.
This should ensure that all our alloca() based allocations are subject
to this limit.
afaics glibc offers three alloca() based APIs: alloca() itself,
strndupa() + strdupa(). With this we have now replacements for all of
them, that take the limit into account.
* flag-set.cocci: perform the transformation only if the second
argument is a constant
* sd-journal/lookup3.c: skip the cocci completely for this file, since
it's not "ours"
* strjoina.cocci: skip the transformation on the "test_strjoina" test,
since it intentionally tests the "incorrect" expression we're trying to
transform (the same thing was already done in strjoin.cocci)
to drop braces around single-line if statements. Also, prefix it with
zz- so it runs as the last one, so it's able to fix stuff tweaked by
previous transformations.
Coccinelle can't do this automagically and requires we supply it
respective header files. Unfortunately, the option for this
(--macro-file=) can be used only once, so let's create our own
macro file by collecting macros needed for the semantic parser
to be happy.
The original issue with this transformation was that we were replacing
the whole if statement instead of just the expression inside. That
caused the code to be weirdly formatted, as Coccinelle put a new block
around each replaced if statement.
This version replaces just the inner expression if it's in its incorrect
form, otherwise it just accepts it (to avoid recursion).
