selftests/bpf: Test load and dump metadata with btftool and skel

This is a simple test to check that loading and dumping metadata
in btftool works, whether or not metadata contents are used by the
program.

A C test is also added to make sure the skeleton code can read the
metadata values.

Signed-off-by: YiFei Zhu <zhuyifei@google.com>
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Cc: YiFei Zhu <zhuyifei1999@gmail.com>
Link: https://lore.kernel.org/bpf/20200915234543.3220146-6-sdf@google.com

1 files changed, 82 insertions, 0 deletions

diff --git a/tools/testing/selftests/bpf/test_bpftool_metadata.sh b/tools/testing/selftests/bpf/test_bpftool_metadata.sh
new file mode 100755
index 000000000000..1bf81b49457a
--- /dev/null
+++ b/tools/testing/selftests/bpf/test_bpftool_metadata.sh
@@ -0,0 +1,82 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+
+# Kselftest framework requirement - SKIP code is 4.
+ksft_skip=4
+
+TESTNAME=bpftool_metadata
+BPF_FS=$(awk '$3 == "bpf" {print $2; exit}' /proc/mounts)
+BPF_DIR=$BPF_FS/test_$TESTNAME
+
+_cleanup()
+{
+	set +e
+	rm -rf $BPF_DIR 2> /dev/null
+}
+
+cleanup_skip()
+{
+	echo "selftests: $TESTNAME [SKIP]"
+	_cleanup
+
+	exit $ksft_skip
+}
+
+cleanup()
+{
+	if [ "$?" = 0 ]; then
+		echo "selftests: $TESTNAME [PASS]"
+	else
+		echo "selftests: $TESTNAME [FAILED]"
+	fi
+	_cleanup
+}
+
+if [ $(id -u) -ne 0 ]; then
+	echo "selftests: $TESTNAME [SKIP] Need root privileges"
+	exit $ksft_skip
+fi
+
+if [ -z "$BPF_FS" ]; then
+	echo "selftests: $TESTNAME [SKIP] Could not run test without bpffs mounted"
+	exit $ksft_skip
+fi
+
+if ! bpftool version > /dev/null 2>&1; then
+	echo "selftests: $TESTNAME [SKIP] Could not run test without bpftool"
+	exit $ksft_skip
+fi
+
+set -e
+
+trap cleanup_skip EXIT
+
+mkdir $BPF_DIR
+
+trap cleanup EXIT
+
+bpftool prog load metadata_unused.o $BPF_DIR/unused
+
+METADATA_PLAIN="$(bpftool prog)"
+echo "$METADATA_PLAIN" | grep 'a = "foo"' > /dev/null
+echo "$METADATA_PLAIN" | grep 'b = 1' > /dev/null
+
+bpftool prog --json | grep '"metadata":{"a":"foo","b":1}' > /dev/null
+
+bpftool map | grep 'metadata.rodata' > /dev/null
+
+rm $BPF_DIR/unused
+
+bpftool prog load metadata_used.o $BPF_DIR/used
+
+METADATA_PLAIN="$(bpftool prog)"
+echo "$METADATA_PLAIN" | grep 'a = "bar"' > /dev/null
+echo "$METADATA_PLAIN" | grep 'b = 2' > /dev/null
+
+bpftool prog --json | grep '"metadata":{"a":"bar","b":2}' > /dev/null
+
+bpftool map | grep 'metadata.rodata' > /dev/null
+
+rm $BPF_DIR/used
+
+exit 0