tools/lib/bpf/btf_iter.c

File Facts

System

Linux kernel

Corpus path

tools/lib/bpf/btf_iter.c

Extension

.c

Size

4143 bytes

Lines

178

Domain

Support Tooling And Documentation

Bucket

tools

Inferred role

Support Tooling And Documentation: implementation source

Status

source implementation candidate

Why This File Exists

Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

• Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.
• Defines or uses C structs; map object ownership, embedded links, reference counts, and lock ownership.

Dependency Surface

• linux/bpf.h
• linux/btf.h
• btf.h
• libbpf_internal.h

Detected Declarations

• function btf_field_iter_init

Annotated Snippet

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:

Annotation

• Immediate include surface: `linux/bpf.h`, `linux/btf.h`, `btf.h`, `libbpf_internal.h`.
• Detected declarations: `function btf_field_iter_init`.
• Atlas domain: Support Tooling And Documentation / tools.
• Implementation status: source implementation candidate.

Implementation Notes

• This generated page is the file-by-file coverage layer; curated subsystem chapters should link here when they synthesize a multi-file control flow.
• Core OS pages should be promoted from atlas-only to deep-reviewed when they explain data structures, invariants, locking, lifecycle, and C implementation snippets.
• Driver-family pages are intentionally pattern-oriented unless they are part of the selected PCIe/NVMe representative device path.