Commit 33ecca57 authored by Donglin Peng's avatar Donglin Peng Committed by Andrii Nakryiko
Browse files

libbpf: Verify BTF sorting 



This patch checks whether the BTF is sorted by name in ascending
order. If sorted, binary search will be used when looking up types.

Signed-off-by: default avatarDonglin Peng <pengdonglin@xiaomi.com>
Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Acked-by: default avatarEduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/bpf/20260109130003.3313716-6-dolinux.peng@gmail.com
parent d836e5e6

tools/lib/bpf/btf.c

+25 −0
Original line number Diff line number Diff line
@@ -899,6 +899,30 @@ int btf__resolve_type(const struct btf *btf, __u32 type_id) 
	return type_id;

}



static void btf_check_sorted(struct btf *btf)

{

	__u32 i, n, named_start_id = 0;



	n = btf__type_cnt(btf);

	for (i = btf->start_id + 1; i < n; i++) {

		struct btf_type *ta = btf_type_by_id(btf, i - 1);

		struct btf_type *tb = btf_type_by_id(btf, i);

		const char *na = btf__str_by_offset(btf, ta->name_off);

		const char *nb = btf__str_by_offset(btf, tb->name_off);



		if (strcmp(na, nb) > 0)

			return;



		if (named_start_id == 0 && na[0] != '\0')

			named_start_id = i - 1;

		if (named_start_id == 0 && nb[0] != '\0')

			named_start_id = i;

	}



	if (named_start_id)

		btf->named_start_id = named_start_id;

}



static __s32 btf_find_type_by_name_bsearch(const struct btf *btf, const char *name,

					   __s32 start_id)

{
@@ -1130,6 +1154,7 @@ static struct btf *btf_new(const void *data, __u32 size, struct btf *base_btf, b 
	err = err ?: btf_sanity_check(btf);

	if (err)

		goto done;

	btf_check_sorted(btf);



done:

	if (err) {