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 <keesc...@chromium.org> Cc: Gustavo A. R. Silva <gustavo...@kernel.org> Signed-off-by: Denis Efremov <efre...@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@ +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) -- 2.26.2
