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

   1 // SPDX-License-Identifier: GPL-2.0
   2 // Copyright (c) 2024 Andrea Righi <[email protected]>
   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 }