tools/testing/selftests/bpf/progs/test_libbpf_get_fd_by_id_opts.c

File Facts

System

Linux kernel

Corpus path

tools/testing/selftests/bpf/progs/test_libbpf_get_fd_by_id_opts.c

Extension

.c

Size

706 bytes

Lines

38

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

• vmlinux.h
• errno.h
• bpf/bpf_helpers.h
• bpf/bpf_tracing.h

Detected Declarations

• function BPF_PROG

Annotated Snippet

// SPDX-License-Identifier: GPL-2.0

/*
 * Copyright (C) 2022 Huawei Technologies Duesseldorf GmbH
 *
 * Author: Roberto Sassu <roberto.sassu@huawei.com>
 */

#include "vmlinux.h"
#include <errno.h>
#include <bpf/bpf_helpers.h>
#include <bpf/bpf_tracing.h>

/* From include/linux/mm.h. */
#define FMODE_WRITE	0x2

struct {
	__uint(type, BPF_MAP_TYPE_ARRAY);
	__uint(max_entries, 1);
	__type(key, __u32);
	__type(value, __u32);
} data_input SEC(".maps");

char _license[] SEC("license") = "GPL";

SEC("lsm/bpf_map")
int BPF_PROG(check_access, struct bpf_map *map, fmode_t fmode)
{
	if (map != (struct bpf_map *)&data_input)
		return 0;

	if (fmode & FMODE_WRITE)
		return -EACCES;
	barrier();

	return 0;
}

Annotation

• Immediate include surface: `vmlinux.h`, `errno.h`, `bpf/bpf_helpers.h`, `bpf/bpf_tracing.h`.
• Detected declarations: `function BPF_PROG`.
• 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.