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
8 char _license[] SEC("license") = "GPL";
9
10 struct sample {
11 int pid;
12 int seq;
13 long value;
14 char comm[16];
15 };
16
17 struct {
18 __uint(type, BPF_MAP_TYPE_RINGBUF);
19 } ringbuf SEC(".maps");
20
21 struct {
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 */
29 int pid = 0;
30
31 /* inner state */
32 long seq = 0;
33
34 SEC("fentry/" SYS_PREFIX "sys_getpgid")
35 int 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
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