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// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
/* Copyright (c) 2021 Facebook */
/* Copyright (c) 2024, Oracle and/or its affiliates. */
#ifdef __KERNEL__
#include <linux/bpf.h>
#include <linux/btf.h>
#define btf_var_secinfos(t) (struct btf_var_secinfo *)btf_type_var_secinfo(t)
#else
#include "btf.h"
#include "libbpf_internal.h"
#endif
int btf_field_iter_init(struct btf_field_iter *it, struct btf_type *t,
enum btf_field_iter_kind iter_kind)
{
it->p = NULL;
it->m_idx = -1;
it->off_idx = 0;
it->vlen = 0;
switch (iter_kind) {
case BTF_FIELD_ITER_IDS:
switch (btf_kind(t)) {
case BTF_KIND_UNKN:
case BTF_KIND_INT:
case BTF_KIND_FLOAT:
case BTF_KIND_ENUM:
case BTF_KIND_ENUM64:
it->desc = (struct btf_field_desc) {};
break;
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:
case BTF_KIND_VAR:
case BTF_KIND_DECL_TAG:
case BTF_KIND_TYPE_TAG:
it->desc = (struct btf_field_desc) { 1, {offsetof(struct btf_type, type)} };
break;
case BTF_KIND_ARRAY:
it->desc = (struct btf_field_desc) {
2, {sizeof(struct btf_type) + offsetof(struct btf_array, type),
sizeof(struct btf_type) + offsetof(struct btf_array, index_type)}
};
break;
case BTF_KIND_STRUCT:
case BTF_KIND_UNION:
it->desc = (struct btf_field_desc) {
0, {},
sizeof(struct btf_member),
1, {offsetof(struct btf_member, type)}
};
break;
case BTF_KIND_FUNC_PROTO:
it->desc = (struct btf_field_desc) {
1, {offsetof(struct btf_type, type)},
sizeof(struct btf_param),
1, {offsetof(struct btf_param, type)}
};
break;
case BTF_KIND_DATASEC:
it->desc = (struct btf_field_desc) {
0, {},
sizeof(struct btf_var_secinfo),
1, {offsetof(struct btf_var_secinfo, type)}
};
break;
default:
return -EINVAL;
}
break;
case BTF_FIELD_ITER_STRS:
switch (btf_kind(t)) {
case BTF_KIND_UNKN:
it->desc = (struct btf_field_desc) {};
break;
case BTF_KIND_INT:
case BTF_KIND_FLOAT:
case BTF_KIND_FWD:
case BTF_KIND_ARRAY:
case BTF_KIND_CONST:
case BTF_KIND_VOLATILE:
case BTF_KIND_RESTRICT:
case BTF_KIND_PTR:
case BTF_KIND_TYPEDEF:
case BTF_KIND_FUNC:
case BTF_KIND_VAR:
case BTF_KIND_DECL_TAG:
case BTF_KIND_TYPE_TAG:
case BTF_KIND_DATASEC:
it->desc = (struct btf_field_desc) {
1, {offsetof(struct btf_type, name_off)}
};
break;
case BTF_KIND_ENUM:
it->desc = (struct btf_field_desc) {
1, {offsetof(struct btf_type, name_off)},
sizeof(struct btf_enum),
1, {offsetof(struct btf_enum, name_off)}
};
break;
case BTF_KIND_ENUM64:
it->desc = (struct btf_field_desc) {
1, {offsetof(struct btf_type, name_off)},
sizeof(struct btf_enum64),
1, {offsetof(struct btf_enum64, name_off)}
};
break;
case BTF_KIND_STRUCT:
case BTF_KIND_UNION:
it->desc = (struct btf_field_desc) {
1, {offsetof(struct btf_type, name_off)},
sizeof(struct btf_member),
1, {offsetof(struct btf_member, name_off)}
};
break;
case BTF_KIND_FUNC_PROTO:
it->desc = (struct btf_field_desc) {
1, {offsetof(struct btf_type, name_off)},
sizeof(struct btf_param),
1, {offsetof(struct btf_param, name_off)}
};
break;
default:
return -EINVAL;
}
break;
default:
return -EINVAL;
}
if (it->desc.m_sz)
it->vlen = btf_vlen(t);
it->p = t;
return 0;
}
__u32 *btf_field_iter_next(struct btf_field_iter *it)
{
if (!it->p)
return NULL;
if (it->m_idx < 0) {
if (it->off_idx < it->desc.t_off_cnt)
return it->p + it->desc.t_offs[it->off_idx++];
/* move to per-member iteration */
it->m_idx = 0;
it->p += sizeof(struct btf_type);
it->off_idx = 0;
}
/* if type doesn't have members, stop */
if (it->desc.m_sz == 0) {
it->p = NULL;
return NULL;
}
if (it->off_idx >= it->desc.m_off_cnt) {
/* exhausted this member's fields, go to the next member */
it->m_idx++;
it->p += it->desc.m_sz;
it->off_idx = 0;
}
if (it->m_idx < it->vlen)
return it->p + it->desc.m_offs[it->off_idx++];
it->p = NULL;
return NULL;
}
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