Commit bd70a8fb authored by Eduard Zingerman's avatar Eduard Zingerman Committed by Andrii Nakryiko
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bpf: Allow all printable characters in BTF DATASEC names 



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: default avatarEduard Zingerman <eddyz87@gmail.com>
Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20240306104529.6453-15-eddyz87@gmail.com
parent 733e5e87

kernel/bpf/btf.c

+15 −1
Original line number Diff line number Diff line
@@ -809,9 +809,23 @@ static bool btf_name_valid_identifier(const struct btf *btf, u32 offset) 
	return __btf_name_valid(btf, offset);

}



/* 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)