On Tue, Feb 05, 2019 at 04:29:49PM -0800, Andrii Nakryiko wrote:
> This patch exposes two new APIs btf__get_raw_data_size() and
> btf__get_raw_data() that allows to get a copy of raw BTF data out of
> struct btf. This is useful for external programs that need to manipulate
> raw data, e.g., pahole using btf__dedup() to deduplicate BTF type info
> and then writing it back to file.
>
> Signed-off-by: Andrii Nakryiko <andr...@fb.com>
> Acked-by: Song Liu <songliubrav...@fb.com>
> ---
> tools/lib/bpf/btf.c | 10 ++++++++++
> tools/lib/bpf/btf.h | 2 ++
> tools/lib/bpf/libbpf.map | 2 ++
> 3 files changed, 14 insertions(+)
>
> diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c
> index 1c2ba7182400..34bfb3641aac 100644
> --- a/tools/lib/bpf/btf.c
> +++ b/tools/lib/bpf/btf.c
> @@ -437,6 +437,16 @@ int btf__fd(const struct btf *btf)
> return btf->fd;
> }
>
> +__u32 btf__get_raw_data_size(const struct btf *btf)
> +{
> + return btf->data_size;
> +}
> +
> +void btf__get_raw_data(const struct btf *btf, char *data)
> +{
> + memcpy(data, btf->data, btf->data_size);
> +}
I cannot think of any other way to use this api,
but to call btf__get_raw_data_size() first,
then malloc that much memory and then call btf__get_raw_data()
to store btf into it.
If so, may be api should be single call that allocates, copies,
and returns pointer to new mem and its size?
Probably less error prone?
