1// SPDX-License-Identifier: GPL-2.0
 2// Copyright (c) 2020 Facebook
 3
 4#include <linux/bpf.h>
 5#include <bpf/bpf_helpers.h>
 6
 7char _license[] SEC("license") = "GPL";
 8
 9struct sample {
10	int pid;
11	int seq;
12	long value;
13	char comm[16];
14};
15
16struct ringbuf_map {
17	__uint(type, BPF_MAP_TYPE_RINGBUF);
18	/* libbpf will adjust to valid page size */
19	__uint(max_entries, 1000);
20} ringbuf1 SEC(".maps"),
21  ringbuf2 SEC(".maps");
22
23struct {
24	__uint(type, BPF_MAP_TYPE_ARRAY_OF_MAPS);
25	__uint(max_entries, 4);
26	__type(key, int);
27	__array(values, struct ringbuf_map);
28} ringbuf_arr SEC(".maps") = {
29	.values = {
30		[0] = &ringbuf1,
31		[2] = &ringbuf2,
32	},
33};
34
35struct {
36	__uint(type, BPF_MAP_TYPE_HASH_OF_MAPS);
37	__uint(max_entries, 1);
38	__type(key, int);
39	__array(values, struct ringbuf_map);
40} ringbuf_hash SEC(".maps") = {
41	.values = {
42		[0] = &ringbuf1,
43	},
44};
45
46/* inputs */
47int pid = 0;
48int target_ring = 0;
49long value = 0;
50
51/* outputs */
52long total = 0;
53long dropped = 0;
54long skipped = 0;
55
56SEC("tp/syscalls/sys_enter_getpgid")
57int test_ringbuf(void *ctx)
58{
59	int cur_pid = bpf_get_current_pid_tgid() >> 32;
60	struct sample *sample;
61	void *rb;
 
62
63	if (cur_pid != pid)
64		return 0;
65
66	rb = bpf_map_lookup_elem(&ringbuf_arr, &target_ring);
67	if (!rb) {
68		skipped += 1;
69		return 1;
70	}
71
72	sample = bpf_ringbuf_reserve(rb, sizeof(*sample), 0);
73	if (!sample) {
74		dropped += 1;
75		return 1;
76	}
77
78	sample->pid = pid;
79	bpf_get_current_comm(sample->comm, sizeof(sample->comm));
80	sample->value = value;
81
82	sample->seq = total;
83	total += 1;
84
85	bpf_ringbuf_submit(sample, 0);
86
87	return 0;
88}

 1// SPDX-License-Identifier: GPL-2.0
 2// Copyright (c) 2020 Facebook
 3
 4#include <linux/bpf.h>
 5#include <bpf/bpf_helpers.h>
 6
 7char _license[] SEC("license") = "GPL";
 8
 9struct sample {
10	int pid;
11	int seq;
12	long value;
13	char comm[16];
14};
15
16struct ringbuf_map {
17	__uint(type, BPF_MAP_TYPE_RINGBUF);
 
 
18} ringbuf1 SEC(".maps"),
19  ringbuf2 SEC(".maps");
20
21struct {
22	__uint(type, BPF_MAP_TYPE_ARRAY_OF_MAPS);
23	__uint(max_entries, 4);
24	__type(key, int);
25	__array(values, struct ringbuf_map);
26} ringbuf_arr SEC(".maps") = {
27	.values = {
28		[0] = &ringbuf1,
29		[2] = &ringbuf2,
30	},
31};
32
33struct {
34	__uint(type, BPF_MAP_TYPE_HASH_OF_MAPS);
35	__uint(max_entries, 1);
36	__type(key, int);
37	__array(values, struct ringbuf_map);
38} ringbuf_hash SEC(".maps") = {
39	.values = {
40		[0] = &ringbuf1,
41	},
42};
43
44/* inputs */
45int pid = 0;
46int target_ring = 0;
47long value = 0;
48
49/* outputs */
50long total = 0;
51long dropped = 0;
52long skipped = 0;
53
54SEC("tp/syscalls/sys_enter_getpgid")
55int test_ringbuf(void *ctx)
56{
57	int cur_pid = bpf_get_current_pid_tgid() >> 32;
58	struct sample *sample;
59	void *rb;
60	int zero = 0;
61
62	if (cur_pid != pid)
63		return 0;
64
65	rb = bpf_map_lookup_elem(&ringbuf_arr, &target_ring);
66	if (!rb) {
67		skipped += 1;
68		return 1;
69	}
70
71	sample = bpf_ringbuf_reserve(rb, sizeof(*sample), 0);
72	if (!sample) {
73		dropped += 1;
74		return 1;
75	}
76
77	sample->pid = pid;
78	bpf_get_current_comm(sample->comm, sizeof(sample->comm));
79	sample->value = value;
80
81	sample->seq = total;
82	total += 1;
83
84	bpf_ringbuf_submit(sample, 0);
85
86	return 0;
87}