Commit e7ac331b authored by Alan Maguire's avatar Alan Maguire Committed by Andrii Nakryiko
Browse files

libbpf: Split field iter code into its own file kernel 



This will allow it to be shared with the kernel.  No functional change.

Suggested-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Signed-off-by: default avatarAlan Maguire <alan.maguire@oracle.com>
Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20240620091733.1967885-4-alan.maguire@oracle.com
parent d4e48e3d

tools/lib/bpf/Build

+1 −1
Original line number Diff line number Diff line 
libbpf-y := libbpf.o bpf.o nlattr.o btf.o libbpf_errno.o str_error.o \

	    netlink.o bpf_prog_linfo.o libbpf_probes.o hashmap.o \

	    btf_dump.o ringbuf.o strset.o linker.o gen_loader.o relo_core.o \

	    usdt.o zip.o elf.o features.o btf_relocate.o
 
	    usdt.o zip.o elf.o features.o btf_iter.o btf_relocate.o

tools/lib/bpf/btf.c

+0 −162
Original line number Diff line number Diff line
@@ -5093,168 +5093,6 @@ struct btf *btf__load_module_btf(const char *module_name, struct btf *vmlinux_bt 
	return btf__parse_split(path, vmlinux_btf);

}



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;

}



int btf_ext_visit_type_ids(struct btf_ext *btf_ext, type_id_visit_fn visit, void *ctx)

{

	const struct btf_ext_info *seg;

tools/lib/bpf/btf_iter.c

0 → 100644
+169 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)

/* Copyright (c) 2021 Facebook */

/* Copyright (c) 2024, Oracle and/or its affiliates. */



#include "btf.h"

#include "libbpf_internal.h"



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;

}