selftests/bpf: use btf__parse_elf to check presence of BTF/BTF.ext

Switch test_btf.c to rely on btf__parse_elf to check presence of BTF and
BTF.ext data, instead of implementing its own ELF parsing.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

diff --git a/tools/testing/selftests/bpf/test_btf.c b/tools/testing/selftests/bpf/test_btf.c
index 42c1ce9..289daf5 100644 (file)
--- a/tools/testing/selftests/bpf/test_btf.c
+++ b/tools/testing/selftests/bpf/test_btf.c
@@ -4025,62 +4025,13 @@ static struct btf_file_test file_tests[] = {
 },
 };
 
-static int file_has_btf_elf(const char *fn, bool *has_btf_ext)
-{
-       Elf_Scn *scn = NULL;
-       GElf_Ehdr ehdr;
-       int ret = 0;
-       int elf_fd;
-       Elf *elf;
-
-       if (CHECK(elf_version(EV_CURRENT) == EV_NONE,
-                 "elf_version(EV_CURRENT) == EV_NONE"))
-               return -1;
-
-       elf_fd = open(fn, O_RDONLY);
-       if (CHECK(elf_fd == -1, "open(%s): errno:%d", fn, errno))
-               return -1;
-
-       elf = elf_begin(elf_fd, ELF_C_READ, NULL);
-       if (CHECK(!elf, "elf_begin(%s): %s", fn, elf_errmsg(elf_errno()))) {
-               ret = -1;
-               goto done;
-       }
-
-       if (CHECK(!gelf_getehdr(elf, &ehdr), "!gelf_getehdr(%s)", fn)) {
-               ret = -1;
-               goto done;
-       }
-
-       while ((scn = elf_nextscn(elf, scn))) {
-               const char *sh_name;
-               GElf_Shdr sh;
-
-               if (CHECK(gelf_getshdr(scn, &sh) != &sh,
-                         "file:%s gelf_getshdr != &sh", fn)) {
-                       ret = -1;
-                       goto done;
-               }
-
-               sh_name = elf_strptr(elf, ehdr.e_shstrndx, sh.sh_name);
-               if (!strcmp(sh_name, BTF_ELF_SEC))
-                       ret = 1;
-               if (!strcmp(sh_name, BTF_EXT_ELF_SEC))
-                       *has_btf_ext = true;
-       }
-
-done:
-       close(elf_fd);
-       elf_end(elf);
-       return ret;
-}
-
 static int do_test_file(unsigned int test_num)
 {
        const struct btf_file_test *test = &file_tests[test_num - 1];
        const char *expected_fnames[] = {"_dummy_tracepoint",
                                         "test_long_fname_1",
                                         "test_long_fname_2"};
+       struct btf_ext *btf_ext = NULL;
        struct bpf_prog_info info = {};
        struct bpf_object *obj = NULL;
        struct bpf_func_info *finfo;
@@ -4095,15 +4046,19 @@ static int do_test_file(unsigned int test_num)
        fprintf(stderr, "BTF libbpf test[%u] (%s): ", test_num,
                test->file);
 
-       err = file_has_btf_elf(test->file, &has_btf_ext);
-       if (err == -1)
-               return err;
-
-       if (err == 0) {
-               fprintf(stderr, "SKIP. No ELF %s found", BTF_ELF_SEC);
-               skip_cnt++;
-               return 0;
+       btf = btf__parse_elf(test->file, &btf_ext);
+       if (IS_ERR(btf)) {
+               if (PTR_ERR(btf) == -ENOENT) {
+                       fprintf(stderr, "SKIP. No ELF %s found", BTF_ELF_SEC);
+                       skip_cnt++;
+                       return 0;
+               }
+               return PTR_ERR(btf);
        }
+       btf__free(btf);
+
+       has_btf_ext = btf_ext != NULL;
+       btf_ext__free(btf_ext);
 
        obj = bpf_object__open(test->file);
        if (CHECK(IS_ERR(obj), "obj: %ld", PTR_ERR(obj)))