1 files changed, 248 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/prog_tests/btf_dump.c b/tools/testing/selftests/bpf/prog_tests/btf_dump.c
new file mode 100644
index 000000000..c60091ee8
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/btf_dump.c
@@ -0,0 +1,248 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <test_progs.h>
+#include <bpf/btf.h>
+
+static int duration = 0;
+
+void btf_dump_printf(void *ctx, const char *fmt, va_list args)
+{
+	vfprintf(ctx, fmt, args);
+}
+
+static struct btf_dump_test_case {
+	const char *name;
+	const char *file;
+	bool known_ptr_sz;
+	struct btf_dump_opts opts;
+} btf_dump_test_cases[] = {
+	{"btf_dump: syntax", "btf_dump_test_case_syntax", true, {}},
+	{"btf_dump: ordering", "btf_dump_test_case_ordering", false, {}},
+	{"btf_dump: padding", "btf_dump_test_case_padding", true, {}},
+	{"btf_dump: packing", "btf_dump_test_case_packing", true, {}},
+	{"btf_dump: bitfields", "btf_dump_test_case_bitfields", true, {}},
+	{"btf_dump: multidim", "btf_dump_test_case_multidim", false, {}},
+	{"btf_dump: namespacing", "btf_dump_test_case_namespacing", false, {}},
+};
+
+static int btf_dump_all_types(const struct btf *btf,
+			      const struct btf_dump_opts *opts)
+{
+	size_t type_cnt = btf__get_nr_types(btf);
+	struct btf_dump *d;
+	int err = 0, id;
+
+	d = btf_dump__new(btf, NULL, opts, btf_dump_printf);
+	if (IS_ERR(d))
+		return PTR_ERR(d);
+
+	for (id = 1; id <= type_cnt; id++) {
+		err = btf_dump__dump_type(d, id);
+		if (err)
+			goto done;
+	}
+
+done:
+	btf_dump__free(d);
+	return err;
+}
+
+static int test_btf_dump_case(int n, struct btf_dump_test_case *t)
+{
+	char test_file[256], out_file[256], diff_cmd[1024];
+	struct btf *btf = NULL;
+	int err = 0, fd = -1;
+	FILE *f = NULL;
+
+	snprintf(test_file, sizeof(test_file), "%s.o", t->file);
+
+	btf = btf__parse_elf(test_file, NULL);
+	if (CHECK(IS_ERR(btf), "btf_parse_elf",
+	    "failed to load test BTF: %ld\n", PTR_ERR(btf))) {
+		err = -PTR_ERR(btf);
+		btf = NULL;
+		goto done;
+	}
+
+	/* tests with t->known_ptr_sz have no "long" or "unsigned long" type,
+	 * so it's impossible to determine correct pointer size; but if they
+	 * do, it should be 8 regardless of host architecture, becaues BPF
+	 * target is always 64-bit
+	 */
+	if (!t->known_ptr_sz) {
+		btf__set_pointer_size(btf, 8);
+	} else {
+		CHECK(btf__pointer_size(btf) != 8, "ptr_sz", "exp %d, got %zu\n",
+		      8, btf__pointer_size(btf));
+	}
+
+	snprintf(out_file, sizeof(out_file), "/tmp/%s.output.XXXXXX", t->file);
+	fd = mkstemp(out_file);
+	if (CHECK(fd < 0, "create_tmp", "failed to create file: %d\n", fd)) {
+		err = fd;
+		goto done;
+	}
+	f = fdopen(fd, "w");
+	if (CHECK(f == NULL, "open_tmp",  "failed to open file: %s(%d)\n",
+		  strerror(errno), errno)) {
+		close(fd);
+		goto done;
+	}
+
+	t->opts.ctx = f;
+	err = btf_dump_all_types(btf, &t->opts);
+	fclose(f);
+	close(fd);
+	if (CHECK(err, "btf_dump", "failure during C dumping: %d\n", err)) {
+		goto done;
+	}
+
+	snprintf(test_file, sizeof(test_file), "progs/%s.c", t->file);
+	if (access(test_file, R_OK) == -1)
+		/*
+		 * When the test is run with O=, kselftest copies TEST_FILES
+		 * without preserving the directory structure.
+		 */
+		snprintf(test_file, sizeof(test_file), "%s.c", t->file);
+	/*
+	 * Diff test output and expected test output, contained between
+	 * START-EXPECTED-OUTPUT and END-EXPECTED-OUTPUT lines in test case.
+	 * For expected output lines, everything before '*' is stripped out.
+	 * Also lines containing comment start and comment end markers are
+	 * ignored. 
+	 */
+	snprintf(diff_cmd, sizeof(diff_cmd),
+		 "awk '/START-EXPECTED-OUTPUT/{out=1;next} "
+		 "/END-EXPECTED-OUTPUT/{out=0} "
+		 "/\\/\\*|\\*\\//{next} " /* ignore comment start/end lines */
+		 "out {sub(/^[ \\t]*\\*/, \"\"); print}' '%s' | diff -u - '%s'",
+		 test_file, out_file);
+	err = system(diff_cmd);
+	if (CHECK(err, "diff",
+		  "differing test output, output=%s, err=%d, diff cmd:\n%s\n",
+		  out_file, err, diff_cmd))
+		goto done;
+
+	remove(out_file);
+
+done:
+	btf__free(btf);
+	return err;
+}
+
+static char *dump_buf;
+static size_t dump_buf_sz;
+static FILE *dump_buf_file;
+
+void test_btf_dump_incremental(void)
+{
+	struct btf *btf = NULL;
+	struct btf_dump *d = NULL;
+	struct btf_dump_opts opts;
+	int id, err, i;
+
+	dump_buf_file = open_memstream(&dump_buf, &dump_buf_sz);
+	if (!ASSERT_OK_PTR(dump_buf_file, "dump_memstream"))
+		return;
+	btf = btf__new_empty();
+	if (!ASSERT_OK_PTR(btf, "new_empty"))
+		goto err_out;
+	opts.ctx = dump_buf_file;
+	d = btf_dump__new(btf, NULL, &opts, btf_dump_printf);
+	if (!ASSERT_OK(libbpf_get_error(d), "btf_dump__new"))
+		goto err_out;
+
+	/* First, generate BTF corresponding to the following C code:
+	 *
+	 * enum { VAL = 1 };
+	 *
+	 * struct s { int x; };
+	 *
+	 */
+	id = btf__add_enum(btf, NULL, 4);
+	ASSERT_EQ(id, 1, "enum_id");
+	err = btf__add_enum_value(btf, "VAL", 1);
+	ASSERT_OK(err, "enum_val_ok");
+
+	id = btf__add_int(btf, "int", 4, BTF_INT_SIGNED);
+	ASSERT_EQ(id, 2, "int_id");
+
+	id = btf__add_struct(btf, "s", 4);
+	ASSERT_EQ(id, 3, "struct_id");
+	err = btf__add_field(btf, "x", 2, 0, 0);
+	ASSERT_OK(err, "field_ok");
+
+	for (i = 1; i <= btf__get_nr_types(btf); i++) {
+		err = btf_dump__dump_type(d, i);
+		ASSERT_OK(err, "dump_type_ok");
+	}
+
+	fflush(dump_buf_file);
+	dump_buf[dump_buf_sz] = 0; /* some libc implementations don't do this */
+	ASSERT_STREQ(dump_buf,
+"enum {\n"
+"	VAL = 1,\n"
+"};\n"
+"\n"
+"struct s {\n"
+"	int x;\n"
+"};\n\n", "c_dump1");
+
+	/* Now, after dumping original BTF, append another struct that embeds
+	 * anonymous enum. It also has a name conflict with the first struct:
+	 *
+	 * struct s___2 {
+	 *     enum { VAL___2 = 1 } x;
+	 *     struct s s;
+	 * };
+	 *
+	 * This will test that btf_dump'er maintains internal state properly.
+	 * Note that VAL___2 enum value. It's because we've already emitted
+	 * that enum as a global anonymous enum, so btf_dump will ensure that
+	 * enum values don't conflict;
+	 *
+	 */
+	fseek(dump_buf_file, 0, SEEK_SET);
+
+	id = btf__add_struct(btf, "s", 4);
+	ASSERT_EQ(id, 4, "struct_id");
+	err = btf__add_field(btf, "x", 1, 0, 0);
+	ASSERT_OK(err, "field_ok");
+	err = btf__add_field(btf, "s", 3, 32, 0);
+	ASSERT_OK(err, "field_ok");
+
+	for (i = 1; i <= btf__get_nr_types(btf); i++) {
+		err = btf_dump__dump_type(d, i);
+		ASSERT_OK(err, "dump_type_ok");
+	}
+
+	fflush(dump_buf_file);
+	dump_buf[dump_buf_sz] = 0; /* some libc implementations don't do this */
+	ASSERT_STREQ(dump_buf,
+"struct s___2 {\n"
+"	enum {\n"
+"		VAL___2 = 1,\n"
+"	} x;\n"
+"	struct s s;\n"
+"};\n\n" , "c_dump1");
+
+err_out:
+	fclose(dump_buf_file);
+	free(dump_buf);
+	btf_dump__free(d);
+	btf__free(btf);
+}
+
+void test_btf_dump() {
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(btf_dump_test_cases); i++) {
+		struct btf_dump_test_case *t = &btf_dump_test_cases[i];
+
+		if (!test__start_subtest(t->name))
+			continue;
+
+		test_btf_dump_case(i, &btf_dump_test_cases[i]);
+	}
+	if (test__start_subtest("btf_dump: incremental"))
+		test_btf_dump_incremental();
+}