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
  16 static void (*bpf_trace_printk)(const char *fmt, int fmt_size, ...) =
  17         (void *) 6;
  18
  19 SEC("func=null_lseek file->f_mode offset orig")
  20 int 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
  34 char _license[] SEC("license") = "GPL";
  35 int _version SEC("version") = LINUX_VERSION_CODE;