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

Source file repositories/reference/linux-study-clean/tools/testing/selftests/bpf/progs/mmap_inner_array.c

File Facts

System
Linux kernel
Corpus path
tools/testing/selftests/bpf/progs/mmap_inner_array.c
Extension
.c
Size
1196 bytes
Lines
58
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.

Dependency Surface

Detected Declarations

Annotated Snippet

struct inner_array_type {
	__uint(type, BPF_MAP_TYPE_ARRAY);
	__uint(map_flags, BPF_F_MMAPABLE);
	__type(key, __u32);
	__type(value, __u64);
	__uint(max_entries, 1);
} inner_array SEC(".maps");

struct {
	__uint(type, BPF_MAP_TYPE_HASH_OF_MAPS);
	__uint(key_size, 4);
	__uint(value_size, 4);
	__uint(max_entries, 1);
	__array(values, struct inner_array_type);
} outer_map SEC(".maps");

int pid = 0;
__u64 match_value = 0x13572468;
bool done = false;
bool pid_match = false;
bool outer_map_match = false;

SEC("fentry/" SYS_PREFIX "sys_nanosleep")
int add_to_list_in_inner_array(void *ctx)
{
	__u32 curr_pid, zero = 0;
	struct bpf_map *map;
	__u64 *value;

	curr_pid = (u32)bpf_get_current_pid_tgid();
	if (done || curr_pid != pid)
		return 0;

	pid_match = true;
	map = bpf_map_lookup_elem(&outer_map, &curr_pid);
	if (!map)
		return 0;

	outer_map_match = true;
	value = bpf_map_lookup_elem(map, &zero);
	if (!value)
		return 0;

	*value = match_value;
	done = true;
	return 0;
}

Annotation

Implementation Notes