samples/bpf/syscall_tp_kern.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /* Copyright (c) 2017 Facebook
   3  */
   4 #include <uapi/linux/bpf.h>
   5 #include "bpf_helpers.h"
   6
   7 struct syscalls_enter_open_args {
   8         unsigned long long unused;
   9         long syscall_nr;
  10         long filename_ptr;
  11         long flags;
  12         long mode;
  13 };
  14
  15 struct syscalls_exit_open_args {
  16         unsigned long long unused;
  17         long syscall_nr;
  18         long ret;
  19 };
  20
  21 struct bpf_map_def SEC("maps") enter_open_map = {
  22         .type = BPF_MAP_TYPE_ARRAY,
  23         .key_size = sizeof(u32),
  24         .value_size = sizeof(u32),
  25         .max_entries = 1,
  26 };
  27
  28 struct bpf_map_def SEC("maps") exit_open_map = {
  29         .type = BPF_MAP_TYPE_ARRAY,
  30         .key_size = sizeof(u32),
  31         .value_size = sizeof(u32),
  32         .max_entries = 1,
  33 };
  34
  35 static __always_inline void count(void *map)
  36 {
  37         u32 key = 0;
  38         u32 *value, init_val = 1;
  39
  40         value = bpf_map_lookup_elem(map, &key);
  41         if (value)
  42                 *value += 1;
  43         else
  44                 bpf_map_update_elem(map, &key, &init_val, BPF_NOEXIST);
  45 }
  46
  47 SEC("tracepoint/syscalls/sys_enter_open")
  48 int trace_enter_open(struct syscalls_enter_open_args *ctx)
  49 {
  50         count((void *)&enter_open_map);
  51         return 0;
  52 }
  53
  54 SEC("tracepoint/syscalls/sys_exit_open")
  55 int trace_enter_exit(struct syscalls_exit_open_args *ctx)
  56 {
  57         count((void *)&exit_open_map);
  58         return 0;
  59 }