1#!/bin/sh
2# SPDX-License-Identifier: GPL-2.0-only
3set -e
4
5# Argument 1: Source file to build.
6IN="$1"
7shift
8# Extract just the filename for error messages below.
9FILE="${IN##*/}"
10# Extract the function name for error messages below.
11FUNC="${FILE#*-}"
12FUNC="${FUNC%%-*}"
13FUNC="${FUNC%%.*}"
14# Extract the symbol to test for in build/symbol test below.
15WANT="__${FILE%%-*}"
16
17# Argument 2: Where to write the build log.
18OUT="$1"
19shift
20TMP="${OUT}.tmp"
21
22# Argument 3: Path to "nm" tool.
23NM="$1"
24shift
25
26# Remaining arguments are: $(CC) $(c_flags)
27
28# Clean up temporary file at exit.
29__cleanup() {
30	rm -f "$TMP"
31}
32trap __cleanup EXIT
33
34# Function names in warnings are wrapped in backticks under UTF-8 locales.
35# Run the commands with LANG=C so that grep output will not change.
36export LANG=C
37
38status=
39# Attempt to build a source that is expected to fail with a specific warning.
40if "$@" -Werror -c "$IN" -o "$OUT".o 2> "$TMP" ; then
41	# If the build succeeds, either the test has failed or the
42	# warning may only happen at link time (Clang). In that case,
43	# make sure the expected symbol is unresolved in the symbol list.
44	# If so, FORTIFY is working for this case.
45	if ! $NM -A "$OUT".o | grep -m1 "\bU ${WANT}$" >>"$TMP" ; then
46		status="warning: unsafe ${FUNC}() usage lacked '$WANT' symbol in $IN"
47	fi
48else
49	# If the build failed, check for the warning in the stderr.
50	# GCC:
51	# ./include/linux/fortify-string.h:316:25: error: call to '__write_overflow_field' declared with attribute warning: detected write beyond size of field (1st parameter); maybe use struct_group()? [-Werror=attribute-warning]
52	# Clang 14:
53	# ./include/linux/fortify-string.h:316:4: error: call to __write_overflow_field declared with 'warning' attribute: detected write beyond size of field (1st parameter); maybe use struct_group()? [-Werror,-Wattribute-warning]
54	if ! grep -Eq -m1 "error: call to .?\b${WANT}\b.?" "$TMP" ; then
55		status="warning: unsafe ${FUNC}() usage lacked '$WANT' warning in $IN"
56	fi
57fi
58
59if [ -n "$status" ]; then
60	# Report on failure results, including compilation warnings.
61	echo "$status" | tee "$OUT" >&2
62else
63	# Report on good results, and save any compilation output to log.
64	echo "ok: unsafe ${FUNC}() usage correctly detected with '$WANT' in $IN" >"$OUT"
65fi
66cat "$TMP" >>"$OUT"
67