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

   1 // SPDX-License-Identifier: GPL-2.0
   2 /* Copyright (c) 2021 Facebook */
   3
   4 #include "vmlinux.h"
   5 #include <bpf/bpf_helpers.h>
   6 #include <bpf/bpf_tracing.h>
   7
   8 char _license[] SEC("license") = "GPL";
   9
  10 struct {
  11         __uint(type, BPF_MAP_TYPE_TASK_STORAGE);
  12         __uint(map_flags, BPF_F_NO_PREALLOC);
  13         __type(key, int);
  14         __type(value, long);
  15 } enter_id SEC(".maps");
  16
  17 #define MAGIC_VALUE 0xabcd1234
  18
  19 pid_t target_pid = 0;
  20 int mismatch_cnt = 0;
  21 int enter_cnt = 0;
  22 int exit_cnt = 0;
  23
  24 SEC("tp_btf/sys_enter")
  25 int BPF_PROG(on_enter, struct pt_regs *regs, long id)
  26 {
  27         struct task_struct *task;
  28         long *ptr;
  29
  30         task = bpf_get_current_task_btf();
  31         if (task->pid != target_pid)
  32                 return 0;
  33
  34         ptr = bpf_task_storage_get(&enter_id, task, 0,
  35                                    BPF_LOCAL_STORAGE_GET_F_CREATE);
  36         if (!ptr)
  37                 return 0;
  38
  39         __sync_fetch_and_add(&enter_cnt, 1);
  40         *ptr = MAGIC_VALUE + enter_cnt;
  41
  42         return 0;
  43 }
  44
  45 SEC("tp_btf/sys_exit")
  46 int BPF_PROG(on_exit, struct pt_regs *regs, long id)
  47 {
  48         struct task_struct *task;
  49         long *ptr;
  50
  51         task = bpf_get_current_task_btf();
  52         if (task->pid != target_pid)
  53                 return 0;
  54
  55         ptr = bpf_task_storage_get(&enter_id, task, 0,
  56                                    BPF_LOCAL_STORAGE_GET_F_CREATE);
  57         if (!ptr)
  58                 return 0;
  59
  60         __sync_fetch_and_add(&exit_cnt, 1);
  61         if (*ptr != MAGIC_VALUE + exit_cnt)
  62                 __sync_fetch_and_add(&mismatch_cnt, 1);
  63         return 0;
  64 }