Some transformations generate results we don't want to keep, so
let's disable such transformations for specific files.
Also, disable const-strlen.cocci everywhere, as the STRLEN macro has a
pretty limited scope, so the transformation generates false positives in
most cases.
There's no point in running these transformation for certain files,
mainly anything from src/boot/efi and src/shared/linux, as this code
doesn't have access to our internal utility functions
For example, following transformation:
- isempty(s) ? NULL : s
+ empty_to_null(s)
would get applied to the empty_to_null function itself as well,
causing an infinite recursion, like:
--- src/basic/string-util.h
+++ /tmp/cocci-output-307-9f76e6-string-util.h
@@ -50,11 +50,11 @@ static inline bool isempty(const char *p
}
static inline const char *empty_to_null(const char *p) {
- return isempty(p) ? NULL : p;
+ return empty_to_null(p);
}
Let's avoid that by checking the current match position
For example, the following transformation:
- sizeof(s)-1
+ STRLEN(s)
would replace sizeof by STRLEN even in the STRLEN macro definition
itself, which generates following nonsensical patch:
--- src/basic/macro.h
+++ /tmp/cocci-output-8753-b50773-macro.h
@@ -182,7 +182,7 @@ static inline unsigned long ALIGN_POWER2
* Contrary to strlen(), this is a constant expression.
* @x: a string literal.
*/
-#define STRLEN(x) (sizeof(""x"") - 1)
+#define STRLEN(x) (STRLEN("" x ""))
/*
* container_of - cast a member of a structure out to the containing structure
Let's exclude the macro itself from the transformation to avoid this
The `coccinelle/take-fd.cocci` transformation file attempts to rewrite
r = fd;
fd = -1;
to
r = TAKE_FD(fd);
Unfortunately, using `identifier` or `idexpression` as a metavariable
type in this case wouldn't match more complex location descriptions,
like:
x->fd = fd
fd = -1;
Using 'expression' metavariable type generates false positives,
as you can't specify scope of such expression. The only real example
from the current codebase is the global 'errno' variable, which results
in following patch generated by `spatch`:
--- src/basic/errno-util.h
+++ /tmp/cocci-output-28263-971baa-errno-util.h
@@ -15,8 +15,7 @@ static inline void _reset_errno_(int *sa
#define UNPROTECT_ERRNO \
do { \
- errno = _saved_errno_; \
- _saved_errno_ = -1; \
+ errno = TAKE_FD(_saved_errno_); \
} while (false)
static inline int negative_errno(void) {
Let's explicitly state that the matched expression should not equal
'errno' to avoid this. It's not particularly nice, but it should be
enough, at least for now.
Coccinelle needs a custom isomorphism file with rules (isomorphisms) how
to correctly rewrite conditions with explicit NULL checks (i.e.
if (ptr == NULL)) to their shorter form (i.e. if (!ptr)). Coccinelle
already contains such isomorphisms in its default .iso file, however,
they're in the opposite direction, which results in useless output from
coccinelle/equals-null.cocci.
With this fix, `spatch` should no longer report patches like:
@@ -628,8 +628,9 @@ static int path_deserialize_item(Unit *u
f = path_result_from_string(value);
if (f < 0)
log_unit_debug(u, "Failed to parse result value: %s", value);
- else if (f != PATH_SUCCESS)
- p->result = f;
+ else {if (f != PATH_SUCCESS)
+ p->result = f;
+ }
} else
log_unit_debug(u, "Unknown serialization key: %s", key);
This is partially a refactoring, but also makes many more places use
unlocked operations implicitly, i.e. all users of fopen_temporary().
AFAICT, the uses are always for short-lived files which are not shared
externally, and are just used within the same context. Locking is not
necessary.
We had all kinds of indentation: 2 sp, 3 sp, 4 sp, 8 sp, and mixed.
4 sp was the most common, in particular the majority of scripts under test/
used that. Let's standarize on 4 sp, because many commandlines are long and
there's a lot of nesting, and with 8sp indentation less stuff fits. 4 sp
also seems to be the default indentation, so this will make it less likely
that people will mess up if they don't load the editor config. (I think people
often use vi, and vi has no support to load project-wide configuration
automatically. We distribute a .vimrc file, but it is not loaded by default,
and even the instructions in it seem to discourage its use for security
reasons.)
Also remove the few vim config lines that were left. We should either have them
on all files, or none.
Also remove some strange stuff like '#!/bin/env bash', yikes.
Ideally, coccinelle would strip unnecessary braces too. But I do not see any
option in coccinelle for this, so instead, I edited the patch text using
search&replace to remove the braces. Unfortunately this is not fully automatic,
in particular it didn't deal well with if-else-if-else blocks and ifdefs, so
there is an increased likelikehood be some bugs in such spots.
I also removed part of the patch that coccinelle generated for udev, where we
returns -1 for failure. This should be fixed independently.
They are not needed, because anything that is non-zero is converted
to true.
C11:
> 6.3.1.2: When any scalar value is converted to _Bool, the result is 0 if the
> value compares equal to 0; otherwise, the result is 1.
https://stackoverflow.com/questions/31551888/casting-int-to-bool-in-c-c
spatch is single-threaded, i.e. slow. On my machine it allocates 5 GB of memory
and starts swapping, which makes it even slower. Using parallel makes the whole
thing pleasantly fast.
This way we don't need to repeat the argument twice.
I didn't replace all instances. I think it's better to leave out:
- asserts
- comparisons like x & y == x, which are mathematically equivalent, but
here we aren't checking if flags are set, but if the argument fits in the
flags.
Also, allow run-cocinnelle.sh to be started from any directory.
Unfortunately set -x does not work nicely anymore, because the list is
too verbose. Replace it by an echo line.
We check the same condition at various places. Let's add a trivial,
common helper for this, and use it everywhere.
It's not going to make things much faster or much shorter, but I think a
lot more readable
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.
This macro will read a pointer of any type, return it, and set the
pointer to NULL. This is useful as an explicit concept of passing
ownership of a memory area between pointers.
This takes inspiration from Rust:
https://doc.rust-lang.org/std/option/enum.Option.html#method.take
and was suggested by Alan Jenkins (@sourcejedi).
It drops ~160 lines of code from our codebase, which makes me like it.
Also, I think it clarifies passing of ownership, and thus helps
readability a bit (at least for the initiated who know the new macro)
Let's include the command line to use to get the requested output. This
makes it easy to copy/paste the command line out, and add "--in-place"
to actually apply the changes "run-coccinelle.sh" outputs.
At various places we only want to close fds if they are not
stdin/stdout/stderr, i.e. fds 0, 1, 2. Let's add a unified helper call
for that, and port everything over.
It doesn't work, spits out only rubbish and was already excluded of
run-coccinelle.sh. It's a pitty it doesn't work, but let's drop this
dead piece of code for now.
Apparently O_NONBLOCK is the modern name used in most documentation and
for most cases in our sources. Let's hence replace the old alias
O_NDELAY and stick to O_NONBLOCK everywhere.
On Linux the former is a compat alias to the latter, and that's really
weird, as inside the kernel the two are distinct. Which means we really
should stay away from it.
With these additions, coccinelle finds everything fixed by the first
commit in PR #7695. In order not to needlessly conflict with that PR
this PR won't include those fixes, but only the coccinelle changes to
detect them automatically in the future.
This makes things a bit easier to read I think, and also makes sure we
always use the _unlikely_ wrapper around it, which so far we used
sometimes and other times we didn't. Let's clean that up.
Frantisek Sumsal