[PATCH bpf-next v4 04/17] selftests/bpf: Build BTF fixtures in btf_to_tmpfile()

[Ihor Solodrai <ihor.solodrai@linux.dev>]

test_bpftool_btf_dump() builds each BTF fixture, writes it to a
temporary file, and frees the BTF after the subtests on that file
finish, although they only read the file. Each fixture repeats this
handling, and one that fails to build skips the subtests of all later
fixtures.

Pass the fixture constructor to btf_to_tmpfile(), which frees the BTF
once it is written. A fixture that fails to build now skips only its
own subtests.

Signed-off-by: Ihor Solodrai <ihor.solodrai@linux.dev>
---
 .../bpf/prog_tests/bpftool_btf_dump.c         | 58 +++++++++----------
 1 file changed, 26 insertions(+), 32 deletions(-)

diff --git a/tools/testing/selftests/bpf/prog_tests/bpftool_btf_dump.c b/tools/testing/selftests/bpf/prog_tests/bpftool_btf_dump.c
index 534aa79a4278..80e8e435d702 100644
--- a/tools/testing/selftests/bpf/prog_tests/bpftool_btf_dump.c
+++ b/tools/testing/selftests/bpf/prog_tests/bpftool_btf_dump.c
@@ -109,30 +109,39 @@ static struct btf *mk_loc_btf(void)
 	return btf;
 }
 
-static int btf_to_tmpfile(const struct btf *btf, char *path)
+static int btf_to_tmpfile(struct btf *(*mk)(void), char *path)
 {
 	ssize_t written;
+	struct btf *btf;
 	const void *raw;
+	int err = -1;
 	__u32 sz;
 	int fd;
 
+	btf = mk();
+	if (!btf)
+		return -1;
+
 	raw = btf__raw_data(btf, &sz);
 	if (!ASSERT_OK_PTR(raw, "raw_data"))
-		return -1;
+		goto out;
 
 	snprintf(path, PATH_MAX, "/tmp/bpftool_btf_dump.XXXXXX");
 	fd = mkstemp(path);
 	if (!ASSERT_OK_FD(fd, "mkstemp_btf"))
-		return -1;
+		goto out;
 
 	written = write(fd, raw, sz);
 	close(fd);
 	if (!ASSERT_EQ(written, sz, "write_btf")) {
 		unlink(path);
-		return -1;
+		goto out;
 	}
 
-	return 0;
+	err = 0;
+out:
+	btf__free(btf);
+	return err;
 }
 
 static char *dump_c(const char *btf_path, bool sorted)
@@ -265,33 +274,18 @@ static void test_loc_dump(const char *btf_path)
 void test_bpftool_btf_dump(void)
 {
 	char path[PATH_MAX];
-	struct btf *btf = NULL;
-
-	btf = mk_btf();
-	if (!btf)
-		return;
-
-	if (btf_to_tmpfile(btf, path))
-		goto out_btf;
 
-	if (test__start_subtest("c_sorted"))
-		test_dump(path, true);
-	if (test__start_subtest("c_unsorted"))
-		test_dump(path, false);
-	unlink(path);
-
-	btf__free(btf);
-
-	btf = mk_loc_btf();
-	if (!btf)
-		return;
-
-	if (btf_to_tmpfile(btf, path))
-		goto out_btf;
+	if (!btf_to_tmpfile(mk_btf, path)) {
+		if (test__start_subtest("c_sorted"))
+			test_dump(path, true);
+		if (test__start_subtest("c_unsorted"))
+			test_dump(path, false);
+		unlink(path);
+	}
 
-	if (test__start_subtest("loc_dump"))
-		test_loc_dump(path);
-	unlink(path);
-out_btf:
-	btf__free(btf);
+	if (!btf_to_tmpfile(mk_loc_btf, path)) {
+		if (test__start_subtest("loc_dump"))
+			test_loc_dump(path);
+		unlink(path);
+	}
 }
-- 
2.56.0