1 files changed, 168 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/test_bpftool_build.sh b/tools/testing/selftests/bpf/test_bpftool_build.sh
new file mode 100755
index 000000000..2db3c60e1
--- /dev/null
+++ b/tools/testing/selftests/bpf/test_bpftool_build.sh
@@ -0,0 +1,168 @@
+#!/bin/bash
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+
+case $1 in
+	-h|--help)
+		echo -e "$0 [-j <n>]"
+		echo -e "\tTest the different ways of building bpftool."
+		echo -e ""
+		echo -e "\tOptions:"
+		echo -e "\t\t-j <n>:\tPass -j flag to 'make'."
+		exit 0
+		;;
+esac
+
+J=$*
+
+# Assume script is located under tools/testing/selftests/bpf/. We want to start
+# build attempts from the top of kernel repository.
+SCRIPT_REL_PATH=$(realpath --relative-to=$PWD $0)
+SCRIPT_REL_DIR=$(dirname $SCRIPT_REL_PATH)
+KDIR_ROOT_DIR=$(realpath $PWD/$SCRIPT_REL_DIR/../../../../)
+cd $KDIR_ROOT_DIR
+if [ ! -e tools/bpf/bpftool/Makefile ]; then
+	echo -e "skip:    bpftool files not found!\n"
+	exit 0
+fi
+
+ERROR=0
+TMPDIR=
+
+# If one build fails, continue but return non-0 on exit.
+return_value() {
+	if [ -d "$TMPDIR" ] ; then
+		rm -rf -- $TMPDIR
+	fi
+	exit $ERROR
+}
+trap return_value EXIT
+
+check() {
+	local dir=$(realpath $1)
+
+	echo -n "binary:  "
+	# Returns non-null if file is found (and "false" is run)
+	find $dir -type f -executable -name bpftool -print -exec false {} + && \
+		ERROR=1 && printf "FAILURE: Did not find bpftool\n"
+}
+
+make_and_clean() {
+	echo -e "\$PWD:    $PWD"
+	echo -e "command: make -s $* >/dev/null"
+	make $J -s $* >/dev/null
+	if [ $? -ne 0 ] ; then
+		ERROR=1
+	fi
+	if [ $# -ge 1 ] ; then
+		check ${@: -1}
+	else
+		check .
+	fi
+	(
+		if [ $# -ge 1 ] ; then
+			cd ${@: -1}
+		fi
+		make -s clean
+	)
+	echo
+}
+
+make_with_tmpdir() {
+	local ARGS
+
+	TMPDIR=$(mktemp -d)
+	if [ $# -ge 2 ] ; then
+		ARGS=${@:1:(($# - 1))}
+	fi
+	echo -e "\$PWD:    $PWD"
+	echo -e "command: make -s $ARGS ${@: -1}=$TMPDIR/ >/dev/null"
+	make $J -s $ARGS ${@: -1}=$TMPDIR/ >/dev/null
+	if [ $? -ne 0 ] ; then
+		ERROR=1
+	fi
+	check $TMPDIR
+	rm -rf -- $TMPDIR
+	echo
+}
+
+make_doc_and_clean() {
+	echo -e "\$PWD:    $PWD"
+	echo -e "command: make -s $* doc >/dev/null"
+	RST2MAN_OPTS="--exit-status=1" make $J -s $* doc
+	if [ $? -ne 0 ] ; then
+		ERROR=1
+		printf "FAILURE: Errors or warnings when building documentation\n"
+	fi
+	(
+		if [ $# -ge 1 ] ; then
+			cd ${@: -1}
+		fi
+		make -s doc-clean
+	)
+	echo
+}
+
+echo "Trying to build bpftool"
+echo -e "... through kbuild\n"
+
+if [ -f ".config" ] ; then
+	make_and_clean tools/bpf
+
+	## $OUTPUT is overwritten in kbuild Makefile, and thus cannot be passed
+	## down from toplevel Makefile to bpftool's Makefile.
+
+	# make_with_tmpdir tools/bpf OUTPUT
+	echo -e "skip:    make tools/bpf OUTPUT=<dir> (not supported)\n"
+
+	make_with_tmpdir tools/bpf O
+else
+	echo -e "skip:    make tools/bpf (no .config found)\n"
+	echo -e "skip:    make tools/bpf OUTPUT=<dir> (not supported)\n"
+	echo -e "skip:    make tools/bpf O=<dir> (no .config found)\n"
+fi
+
+echo -e "... from kernel source tree\n"
+
+make_and_clean -C tools/bpf/bpftool
+
+make_with_tmpdir -C tools/bpf/bpftool OUTPUT
+
+make_with_tmpdir -C tools/bpf/bpftool O
+
+echo -e "... from tools/\n"
+cd tools/
+
+make_and_clean bpf
+
+## In tools/bpf/Makefile, function "descend" is called and passes $(O) and
+## $(OUTPUT). We would like $(OUTPUT) to have "bpf/bpftool/" appended before
+## calling bpftool's Makefile, but this is not the case as the "descend"
+## function focuses on $(O)/$(subdir). However, in the present case, updating
+## $(O) to have $(OUTPUT) recomputed from it in bpftool's Makefile does not
+## work, because $(O) is not defined from command line and $(OUTPUT) is not
+## updated in tools/scripts/Makefile.include.
+##
+## Workarounds would require to a) edit "descend" or use an alternative way to
+## call bpftool's Makefile, b) modify the conditions to update $(OUTPUT) and
+## other variables in tools/scripts/Makefile.include (at the risk of breaking
+## the build of other tools), or c) append manually the "bpf/bpftool" suffix to
+## $(OUTPUT) in bpf's Makefile, which may break if targets for other directories
+## use "descend" in the future.
+
+# make_with_tmpdir bpf OUTPUT
+echo -e "skip:    make bpf OUTPUT=<dir> (not supported)\n"
+
+make_with_tmpdir bpf O
+
+echo -e "... from bpftool's dir\n"
+cd bpf/bpftool
+
+make_and_clean
+
+make_with_tmpdir OUTPUT
+
+make_with_tmpdir O
+
+echo -e "Checking documentation build\n"
+# From tools/bpf/bpftool
+make_doc_and_clean