1 // SPDX-License-Identifier: GPL-2.0
2 // Copyright (c) 2024 Andrea Righi <andrea.righi@canonical.com>
3
4 #include <linux/bpf.h>
5 #include <sched.h>
6 #include <unistd.h>
7 #include <bpf/bpf_helpers.h>
8 #include "bpf_misc.h"
9
10 char _license[] SEC("license") = "GPL";
11
12 #define TASK_COMM_LEN 16
13
14 struct sample {
15 int pid;
16 long value;
17 char comm[16];
18 };
19
20 struct {
21 __uint(type, BPF_MAP_TYPE_RINGBUF);
22 } ringbuf SEC(".maps");
23
24 int pid = 0;
25 long value = 0;
26
27 SEC("fentry/" SYS_PREFIX "sys_getpgid")
28 int test_ringbuf_n(void *ctx)
29 {
30 int cur_pid = bpf_get_current_pid_tgid() >> 32;
31 struct sample *sample;
32
33 if (cur_pid != pid)
34 return 0;
35
36 sample = bpf_ringbuf_reserve(&ringbuf, sizeof(*sample), 0);
37 if (!sample)
38 return 0;
39
40 sample->pid = pid;
41 sample->value = value;
42 bpf_get_current_comm(sample->comm, sizeof(sample->comm));
43
44 bpf_ringbuf_submit(sample, 0);
45
46 return 0;
47 }
48
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