libbpf: Make destructors more robust by handling ERR_PTR(err) cases
Most of libbpf "constructors" on failure return ERR_PTR(err) result encoded as
a pointer. It's a common mistake to eventually pass such malformed pointers
into xxx__destroy()/xxx__free() "destructors". So instead of fixing up
clean up code in selftests and user programs, handle such error pointers in
destructors themselves. This works beautifully for NULL pointers passed to
destructors, so might as well just work for error pointers.
Suggested-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20200729232148.896125-1-andriin@fb.com
diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c
index c9e760e..ded5b29 100644
--- a/tools/lib/bpf/btf.c
+++ b/tools/lib/bpf/btf.c
@@ -386,7 +386,7 @@ __s32 btf__find_by_name_kind(const struct btf *btf, const char *type_name,
void btf__free(struct btf *btf)
{
- if (!btf)
+ if (IS_ERR_OR_NULL(btf))
return;
if (btf->fd >= 0)
@@ -1025,7 +1025,7 @@ static int btf_ext_parse_hdr(__u8 *data, __u32 data_size)
void btf_ext__free(struct btf_ext *btf_ext)
{
- if (!btf_ext)
+ if (IS_ERR_OR_NULL(btf_ext))
return;
free(btf_ext->data);
free(btf_ext);