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

File Facts

System

Linux kernel

Corpus path

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

Extension

.c

Size

1005 bytes

Lines

44

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
• bpf/bpf_helpers.h
• bpf/bpf_core_read.h

Detected Declarations

• struct task_struct
• function handle_sys_enter

Annotated Snippet

struct task_struct {
	int tgid;
} __attribute__((preserve_access_index));

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

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

SEC("tp/raw_syscalls/sys_enter")
int handle_sys_enter(void *ctx)
{
	struct task_struct *task = (void *)bpf_get_current_task();
	int tgid = BPF_CORE_READ(task, tgid);
	int zero = 0;
	int real_tgid = bpf_get_current_pid_tgid() >> 32;
	int *exp_tgid = bpf_map_lookup_elem(&exp_tgid_map, &zero);

	/* only pass through sys_enters from test process */
	if (!exp_tgid || *exp_tgid != real_tgid)
		return 0;

	bpf_map_update_elem(&results, &zero, &tgid, 0);

	return 0;
}

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

Annotation

• Immediate include surface: `linux/bpf.h`, `bpf/bpf_helpers.h`, `bpf/bpf_core_read.h`.
• Detected declarations: `struct task_struct`, `function handle_sys_enter`.
• 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.