Re: [PATCH bpf-next 2/6] libbpf: add internal helper to load BTF data by FD

On Fri, Nov 20, 2020 at 10:20 AM Martin KaFai Lau [off-list ref] wrote:

On Thu, Nov 19, 2020 at 03:22:40PM -0800, Andrii Nakryiko wrote:
[ ... ]

quoted

+int btf__get_from_id(__u32 id, struct btf **btf)
+{
+     struct btf *res;
+     int btf_fd;
+
+     *btf = NULL;
+     btf_fd = bpf_btf_get_fd_by_id(id);
+     if (btf_fd < 0)
+             return 0;

It should return an error.

That would break the original behavior with (ret == 0 && btf == NULL),
but I think it's more consistent, so I'll fix this and will add Fixes:
tag.

quoted

+
+     res = btf_get_from_fd(btf_fd, NULL);
+     close(btf_fd);
+     if (IS_ERR(res))
+             return PTR_ERR(res);
+
+     *btf = res;
+     return 0;
 }