LXR linux/tools/perf/tests/bpf-script-test-prologue.c

   1/*
   2 * bpf-script-test-prologue.c
   3 * Test BPF prologue
   4 */
   5#ifndef LINUX_VERSION_CODE
   6# error Need LINUX_VERSION_CODE
   7# error Example: for 4.2 kernel, put 'clang-opt="-DLINUX_VERSION_CODE=0x40200" into llvm section of ~/.perfconfig'
   8#endif
   9#define SEC(NAME) __attribute__((section(NAME), used))
  10
  11#include <uapi/linux/fs.h>
  12
  13#define FMODE_READ              0x1
  14#define FMODE_WRITE             0x2
  15
  16static void (*bpf_trace_printk)(const char *fmt, int fmt_size, ...) =
  17        (void *) 6;
  18
  19SEC("func=null_lseek file->f_mode offset orig")
  20int bpf_func__null_lseek(void *ctx, int err, unsigned long f_mode,
  21                         unsigned long offset, unsigned long orig)
  22{
  23        if (err)
  24                return 0;
  25        if (f_mode & FMODE_WRITE)
  26                return 0;
  27        if (offset & 1)
  28                return 0;
  29        if (orig == SEEK_CUR)
  30                return 0;
  31        return 1;
  32}
  33
  34char _license[] SEC("license") = "GPL";
  35int _version SEC("version") = LINUX_VERSION_CODE;
  36