Messages in this thread | | | Date | Sat, 12 Sep 2020 16:43:13 +0200 (CEST) | From | Julia Lawall <> | Subject | Re: [PATCH v2] coccinelle: misc: add flexible_array.cocci script |
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On Mon, 10 Aug 2020, Denis Efremov wrote:
> Commit 68e4cd17e218 ("docs: deprecated.rst: Add zero-length and one-element > arrays") marks one-element and zero-length arrays as deprecated. Kernel > code should always use "flexible array members" instead. > > The script warns about one-element and zero-length arrays in structs. > > Cc: Kees Cook <keescook@chromium.org> > Cc: Gustavo A. R. Silva <gustavoars@kernel.org> > Signed-off-by: Denis Efremov <efremov@linux.com> > --- > Changes in v2: > - all uapi headers are now filtered-out. Unfortunately, coccinelle > doesn't provide structure names in Location.current_element. > For structures the field is always "something_else". Thus, there is > no easy way to create a list of existing structures in uapi headers > and suppress the warning only for them, but not for the newly added > uapi structures. > - The pattern doesn't require 2+ fields in a structure/union anymore. > Now it also checks single field structures/unions. > - The pattern simplified and now uses disjuction in array elements > (Thanks, Markus) > - Unions are removed from patch mode > - one-element arrays are removed from patch mode. Correct patch may > involve turning the array to a simple field instead of a flexible > array. > > On the current master branch, the rule generates: > - context: https://gist.github.com/evdenis/e2b4323491f9eff35376372df07f723c > - patch: https://gist.github.com/evdenis/46081da9d68ecefd07edc3769cebcf32 > > scripts/coccinelle/misc/flexible_array.cocci | 88 ++++++++++++++++++++ > 1 file changed, 88 insertions(+) > create mode 100644 scripts/coccinelle/misc/flexible_array.cocci > > diff --git a/scripts/coccinelle/misc/flexible_array.cocci b/scripts/coccinelle/misc/flexible_array.cocci > new file mode 100644 > index 000000000000..bf6dcda1783e > --- /dev/null > +++ b/scripts/coccinelle/misc/flexible_array.cocci > @@ -0,0 +1,88 @@ > +// SPDX-License-Identifier: GPL-2.0-only > +/// > +/// Zero-length and one-element arrays are deprecated, see > +/// Documentation/process/deprecated.rst > +/// Flexible-array members should be used instead. > +/// > +// > +// Confidence: High > +// Copyright: (C) 2020 Denis Efremov ISPRAS. > +// Comments: > +// Options: --no-includes --include-headers > + > +virtual context > +virtual report > +virtual org > +virtual patch > + > +@initialize:python@ > +@@ > +def relevant(positions): > + for p in positions: > + if "uapi" in p.file: > + return False > + return True > + > +@r depends on !patch@ > +identifier name, array; > +type T; > +position p : script:python() { relevant(p) }; > +@@ > + > +( > + struct name { > + ... > +* T array@p[\(0\|1\)]; > + }; > +| > + struct { > + ... > +* T array@p[\(0\|1\)]; > + }; > +| > + union name { > + ... > +* T array@p[\(0\|1\)]; > + }; > +| > + union { > + ... > +* T array@p[\(0\|1\)]; > + }; > +) > + > +@depends on patch exists@
exists is not necessary here. There are not multiple control-flow paths through a structure declaration.
> +identifier name, array; > +type T; > +position p : script:python() { relevant(p) }; > +@@ > + > +( > + struct name { > + ... > + T array@p[ > +- 0 > + ]; > + }; > +| > + struct { > + ... > + T array@p[ > +- 0 > + ]; > + }; > +) > + > +@script: python depends on report@ > +p << r.p; > +@@ > + > +msg = "WARNING: use flexible-array member instead" > +coccilib.report.print_report(p[0], msg) > + > +@script: python depends on org@ > +p << r.p; > +@@ > + > +msg = "WARNING: use flexible-array member instead" > +coccilib.org.print_todo(p, msg)
This should be coccilib.org.print_todo(p[0], msg)
julia
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