On Wed, Mar 6, 2024 at 2:45 AM Eduard Zingerman <eddyz87@xxxxxxxxx> wrote:
>
> The intent is to allow libbpf to use SEC("?.struct_ops") to identify
> struct_ops maps that are optional, e.g. like in the following BPF code:
>
> SEC("?.struct_ops")
> struct test_ops optional_map = { ... };
>
> Which yields the following BTF:
>
> ...
> [13] DATASEC '?.struct_ops' size=0 vlen=...
> ...
>
> To load such BTF libbpf rewrites DATASEC name before load.
> After this patch the rewrite won't be necessary.
>
> Signed-off-by: Eduard Zingerman <eddyz87@xxxxxxxxx>
> ---
> kernel/bpf/btf.c | 16 +++++++++++++++-
> 1 file changed, 15 insertions(+), 1 deletion(-)
>
> diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
> index 6ff0bd1a91d5..170d017e8e4a 100644
> --- a/kernel/bpf/btf.c
> +++ b/kernel/bpf/btf.c
> @@ -809,9 +809,23 @@ static bool btf_name_valid_identifier(const struct btf *btf, u32 offset)
> return __btf_name_valid(btf, offset);
We should just rename __btf_name_valid() into
btf_name_valid_indentifier() and use that everywhere. Please consider
a clean up patch as a follow up, thanks!
> }
>
> +/* Allow any printable character in DATASEC names */
> static bool btf_name_valid_section(const struct btf *btf, u32 offset)
> {
> - return __btf_name_valid(btf, offset);
> + /* offset must be valid */
> + const char *src = btf_str_by_offset(btf, offset);
> + const char *src_limit;
> +
> + /* set a limit on identifier length */
> + src_limit = src + KSYM_NAME_LEN;
> + src++;
> + while (*src && src < src_limit) {
> + if (!isprint(*src))
> + return false;
> + src++;
> + }
> +
> + return !*src;
> }
>
> static const char *__btf_name_by_offset(const struct btf *btf, u32 offset)
> --
> 2.43.0
>
