selftests/bpf: convert test_bpftool_metadata.sh into test_progs framework

The test_bpftool_metadata.sh script validates that bpftool properly
returns in its ouptput any metadata generated by bpf programs through
some .rodata sections.

Port this test to the test_progs framework so that it can be executed
automatically in CI. The new test, similarly to the former script,
checks that valid data appears both for textual output and json output,
as well as for both data not used at all and used data. For the json
check part, the expected json string is hardcoded to avoid bringing a
new external dependency (eg: a json deserializer) for test_progs.
As the test is now converted into test_progs, remove the former script.

The newly converted test brings two new subtests:

  #37/1    bpftool_metadata/metadata_unused:OK
  #37/2    bpftool_metadata/metadata_used:OK
  #37      bpftool_metadata:OK
  Summary: 1/2 PASSED, 0 SKIPPED, 0 FAILED

Signed-off-by: Alexis Lothoré (eBPF Foundation) <[email protected]>
---
Changes in v2:
- move the new test in prog_tests directory
- use power of 2 for bpftool output buffer size
- check snprintf return when building commands
- target program by pin path rather than prog name
- remove a few blank lines

Author: Tropicao

tools/testing/selftests/bpf/Makefile

@@ -109,7 +109,6 @@ TEST_PROGS := test_kmod.sh \
 	test_bpftool_build.sh \
 	test_bpftool.sh \
 	test_bpftool_map.sh \
-	test_bpftool_metadata.sh \
 	test_doc_build.sh \
 	test_xsk.sh \
 	test_xdp_features.sh

tools/testing/selftests/bpf/prog_tests/bpftool_metadata.c

@@ -0,0 +1,134 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <bpftool_helpers.h>
+#include <test_progs.h>
+#include <linux/bpf.h>
+#include <string.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/stat.h>
+#include <stdbool.h>
+
+#define BPFFS_DIR	"/sys/fs/bpf/test_metadata"
+#define BPFFS_USED	BPFFS_DIR "/used"
+#define BPFFS_UNUSED	BPFFS_DIR "/unused"
+
+#define BPF_FILE_USED	"metadata_used.bpf.o"
+#define BPF_FILE_UNUSED "metadata_unused.bpf.o"
+
+#define MAX_BPFTOOL_OUTPUT_LEN	(64*1024)
+
+#define MAX_TOKENS_TO_CHECK	3
+static char output[MAX_BPFTOOL_OUTPUT_LEN];
+
+struct test_desc {
+	char *name;
+	char *bpf_prog;
+	char *bpffs_path;
+	char *expected_output[MAX_TOKENS_TO_CHECK];
+	char *expected_output_json[MAX_TOKENS_TO_CHECK];
+};
+
+static int setup(struct test_desc *test)
+{
+	return mkdir(BPFFS_DIR, 0700);
+}
+
+static void cleanup(struct test_desc *test)
+{
+	unlink(test->bpffs_path);
+	rmdir(BPFFS_DIR);
+}
+
+static int check_metadata(char *buf, char * const *tokens, int count)
+{
+	int i;
+
+	for (i = 0; i < count && tokens[i]; i++)
+		if (!strstr(buf, tokens[i]))
+			return 1;
+
+	return 0;
+}
+
+static void run_test(struct test_desc *test)
+{
+	int ret;
+	char cmd[MAX_BPFTOOL_CMD_LEN];
+
+	ret = snprintf(cmd, MAX_BPFTOOL_CMD_LEN, "prog load %s %s",
+			test->bpf_prog, test->bpffs_path);
+	if (!ASSERT_GT(ret, 0, "format prog insert command"))
+		return;
+	ret = run_bpftool_command(cmd);
+	if (!ASSERT_OK(ret, "load program"))
+		return;
+
+	/* Check output with default format */
+	ret = snprintf(cmd, MAX_BPFTOOL_CMD_LEN, "prog show pinned %s",
+		       test->bpffs_path);
+	if (!ASSERT_GT(ret, 0, "format pinned prog check command"))
+		return;
+	ret = get_bpftool_command_output(cmd, output,
+			MAX_BPFTOOL_OUTPUT_LEN);
+	if (ASSERT_OK(ret, "get program info")) {
+		ret = check_metadata(output, test->expected_output,
+				ARRAY_SIZE(test->expected_output));
+		ASSERT_OK(ret, "find metadata");
+	}
+
+	/* Check output with json format */
+	ret = snprintf(cmd, MAX_BPFTOOL_CMD_LEN, "prog -j show pinned %s",
+		       test->bpffs_path);
+	if (!ASSERT_GT(ret, 0, "format pinned prog check command in json"))
+		return;
+	ret = get_bpftool_command_output(cmd, output,
+					 MAX_BPFTOOL_OUTPUT_LEN);
+	if (ASSERT_OK(ret, "get program info in json")) {
+		ret = check_metadata(output, test->expected_output_json,
+				ARRAY_SIZE(test->expected_output_json));
+		ASSERT_OK(ret, "find metadata in json");
+	}
+
+}
+
+static struct test_desc tests[] = {
+	{
+		.name = "metadata_unused",
+		.bpf_prog = BPF_FILE_UNUSED,
+		.bpffs_path = BPFFS_UNUSED,
+		.expected_output = {
+			"a = \"foo\"",
+			"b = 1"
+		},
+		.expected_output_json = {
+			"\"metadata\":{\"a\":\"foo\",\"b\":1}"
+		}
+	},
+	{
+		.name = "metadata_used",
+		.bpf_prog = BPF_FILE_USED,
+		.bpffs_path = BPFFS_USED,
+		.expected_output = {
+			"a = \"bar\"",
+			"b = 2"
+		},
+		.expected_output_json = {
+			"\"metadata\":{\"a\":\"bar\",\"b\":2}"
+		}
+	}
+};
+static const int tests_count = ARRAY_SIZE(tests);
+
+void test_bpftool_metadata(void)
+{
+	int i;
+
+	for (i = 0; i < tests_count; i++) {
+		if (!test__start_subtest(tests[i].name))
+			continue;
+		if (ASSERT_OK(setup(&tests[i]), "setup bpffs pin dir")) {
+			run_test(&tests[i]);
+			cleanup(&tests[i]);
+		}
+	}
+}