Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 69eaab04 authored by Andrii Nakryiko's avatar Andrii Nakryiko Committed by Daniel Borkmann
Browse files

btf: extract BTF type size calculation 



This pre-patch extracts calculation of amount of space taken by BTF type descriptor
for later reuse by btf_dedup functionality.

Signed-off-by: default avatarAndrii Nakryiko <andriin@fb.com>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
parent a8a1f7d0

tools/lib/bpf/btf.c

+46 −52
Original line number Diff line number Diff line
@@ -182,50 +182,53 @@ static int btf_parse_str_sec(struct btf *btf) 
	return 0;

}



static int btf_parse_type_sec(struct btf *btf)

static int btf_type_size(struct btf_type *t)

{

	struct btf_header *hdr = btf->hdr;

	void *nohdr_data = btf->nohdr_data;

	void *next_type = nohdr_data + hdr->type_off;

	void *end_type = nohdr_data + hdr->str_off;



	while (next_type < end_type) {

		struct btf_type *t = next_type;

	int base_size = sizeof(struct btf_type);

	__u16 vlen = BTF_INFO_VLEN(t->info);

		int err;



		next_type += sizeof(*t);

	switch (BTF_INFO_KIND(t->info)) {

	case BTF_KIND_FWD:

	case BTF_KIND_CONST:

	case BTF_KIND_VOLATILE:

	case BTF_KIND_RESTRICT:

	case BTF_KIND_PTR:

	case BTF_KIND_TYPEDEF:

	case BTF_KIND_FUNC:

		return base_size;

	case BTF_KIND_INT:

			next_type += sizeof(int);

			break;

		return base_size + sizeof(__u32);

	case BTF_KIND_ENUM:

		return base_size + vlen * sizeof(struct btf_enum);

	case BTF_KIND_ARRAY:

			next_type += sizeof(struct btf_array);

			break;

		return base_size + sizeof(struct btf_array);

	case BTF_KIND_STRUCT:

	case BTF_KIND_UNION:

			next_type += vlen * sizeof(struct btf_member);

			break;

		case BTF_KIND_ENUM:

			next_type += vlen * sizeof(struct btf_enum);

			break;

		return base_size + vlen * sizeof(struct btf_member);

	case BTF_KIND_FUNC_PROTO:

			next_type += vlen * sizeof(struct btf_param);

			break;

		case BTF_KIND_FUNC:

		case BTF_KIND_TYPEDEF:

		case BTF_KIND_PTR:

		case BTF_KIND_FWD:

		case BTF_KIND_VOLATILE:

		case BTF_KIND_CONST:

		case BTF_KIND_RESTRICT:

			break;

		return base_size + vlen * sizeof(struct btf_param);

	default:

			pr_debug("Unsupported BTF_KIND:%u\n",

			     BTF_INFO_KIND(t->info));

		pr_debug("Unsupported BTF_KIND:%u\n", BTF_INFO_KIND(t->info));

		return -EINVAL;

	}

}



static int btf_parse_type_sec(struct btf *btf)

{

	struct btf_header *hdr = btf->hdr;

	void *nohdr_data = btf->nohdr_data;

	void *next_type = nohdr_data + hdr->type_off;

	void *end_type = nohdr_data + hdr->str_off;



	while (next_type < end_type) {

		struct btf_type *t = next_type;

		int type_size;

		int err;



		type_size = btf_type_size(t);

		if (type_size < 0)

			return type_size;

		next_type += type_size;

		err = btf_add_type(btf, t);

		if (err)

			return err;
@@ -252,21 +255,6 @@ static bool btf_type_is_void_or_null(const struct btf_type *t) 
	return !t || btf_type_is_void(t);

}



static __s64 btf_type_size(const struct btf_type *t)

{

	switch (BTF_INFO_KIND(t->info)) {

	case BTF_KIND_INT:

	case BTF_KIND_STRUCT:

	case BTF_KIND_UNION:

	case BTF_KIND_ENUM:

		return t->size;

	case BTF_KIND_PTR:

		return sizeof(void *);

	default:

		return -EINVAL;

	}

}



#define MAX_RESOLVE_DEPTH 32



__s64 btf__resolve_size(const struct btf *btf, __u32 type_id)
@@ -280,11 +268,16 @@ __s64 btf__resolve_size(const struct btf *btf, __u32 type_id) 
	t = btf__type_by_id(btf, type_id);

	for (i = 0; i < MAX_RESOLVE_DEPTH && !btf_type_is_void_or_null(t);

	     i++) {

		size = btf_type_size(t);

		if (size >= 0)

			break;



		switch (BTF_INFO_KIND(t->info)) {

		case BTF_KIND_INT:

		case BTF_KIND_STRUCT:

		case BTF_KIND_UNION:

		case BTF_KIND_ENUM:

			size = t->size;

			goto done;

		case BTF_KIND_PTR:

			size = sizeof(void *);

			goto done;

		case BTF_KIND_TYPEDEF:

		case BTF_KIND_VOLATILE:

		case BTF_KIND_CONST:
@@ -308,6 +301,7 @@ __s64 btf__resolve_size(const struct btf *btf, __u32 type_id) 
	if (size < 0)

		return -EINVAL;



done:

	if (nelems && size > UINT32_MAX / nelems)

		return -E2BIG;