1// SPDX-License-Identifier: GPL-2.0
2/* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */
3
4#include <linux/bpf.h>
5#include <bpf/bpf_helpers.h>
6#include "bpf_misc.h"
7
8char _license[] SEC("license") = "GPL";
9
10struct sample {
11	int pid;
12	int seq;
13	long value;
14	char comm[16];
15};
16
17struct {
18	__uint(type, BPF_MAP_TYPE_RINGBUF);
19} ringbuf SEC(".maps");
20
21struct {
22	__uint(type, BPF_MAP_TYPE_HASH);
23	__uint(max_entries, 1000);
24	__type(key, struct sample);
25	__type(value, int);
26} hash_map SEC(".maps");
27
28/* inputs */
29int pid = 0;
30
31/* inner state */
32long seq = 0;
33
34SEC("fentry/" SYS_PREFIX "sys_getpgid")
35int test_ringbuf_mem_map_key(void *ctx)
36{
37	int cur_pid = bpf_get_current_pid_tgid() >> 32;
38	struct sample *sample, sample_copy;
39	int *lookup_val;
40
41	if (cur_pid != pid)
42		return 0;
43
44	sample = bpf_ringbuf_reserve(&ringbuf, sizeof(*sample), 0);
45	if (!sample)
46		return 0;
47
48	sample->pid = pid;
49	bpf_get_current_comm(sample->comm, sizeof(sample->comm));
50	sample->seq = ++seq;
51	sample->value = 42;
52
53	/* test using 'sample' (PTR_TO_MEM | MEM_ALLOC) as map key arg
54	 */
55	lookup_val = (int *)bpf_map_lookup_elem(&hash_map, sample);
56	__sink(lookup_val);
57
58	/* workaround - memcpy is necessary so that verifier doesn't
59	 * complain with:
60	 *   verifier internal error: more than one arg with ref_obj_id R3
61	 * when trying to do bpf_map_update_elem(&hash_map, sample, &sample->seq, BPF_ANY);
62	 *
63	 * Since bpf_map_lookup_elem above uses 'sample' as key, test using
64	 * sample field as value below
65	 */
66	__builtin_memcpy(&sample_copy, sample, sizeof(struct sample));
67	bpf_map_update_elem(&hash_map, &sample_copy, &sample->seq, BPF_ANY);
68
69	bpf_ringbuf_submit(sample, 0);
70	return 0;
71}
72