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

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

File Facts

System
Linux kernel
Corpus path
tools/testing/selftests/bpf/progs/test_ringbuf_map_key.c
Extension
.c
Size
1353 bytes
Lines
67
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 sample {
	int pid;
	int seq;
	long value;
	char comm[16];
};

struct {
	__uint(type, BPF_MAP_TYPE_RINGBUF);
} ringbuf SEC(".maps");

struct {
	__uint(type, BPF_MAP_TYPE_HASH);
	__uint(max_entries, 1000);
	__type(key, struct sample);
	__type(value, int);
} hash_map SEC(".maps");

/* inputs */
int pid = 0;

/* inner state */
long seq = 0;

SEC("fentry/" SYS_PREFIX "sys_getpgid")
int test_ringbuf_mem_map_key(void *ctx)
{
	int cur_pid = bpf_get_current_pid_tgid() >> 32;
	struct sample *sample;
	int *lookup_val;

	if (cur_pid != pid)
		return 0;

	sample = bpf_ringbuf_reserve(&ringbuf, sizeof(*sample), 0);
	if (!sample)
		return 0;

	sample->pid = pid;
	bpf_get_current_comm(sample->comm, sizeof(sample->comm));
	sample->seq = ++seq;
	sample->value = 42;

	/* test using 'sample' (PTR_TO_MEM | MEM_ALLOC) as map key arg
	 */
	lookup_val = (int *)bpf_map_lookup_elem(&hash_map, sample);
	__sink(lookup_val);

	/*
	 * Since bpf_map_lookup_elem above uses 'sample' as key, test using
	 * sample field as value below
	 */
	bpf_map_update_elem(&hash_map, sample, &sample->seq, BPF_ANY);

	bpf_ringbuf_submit(sample, 0);
	return 0;
}

Annotation

Implementation Notes