Linux Perf
bpf-script-test-prologue.c
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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 /*
14  * If CONFIG_PROFILE_ALL_BRANCHES is selected,
15  * 'if' is redefined after include kernel header.
16  * Recover 'if' for BPF object code.
17  */
18 #ifdef if
19 # undef if
20 #endif
21 
22 #define FMODE_READ 0x1
23 #define FMODE_WRITE 0x2
24 
25 static void (*bpf_trace_printk)(const char *fmt, int fmt_size, ...) =
26  (void *) 6;
27 
28 SEC("func=null_lseek file->f_mode offset orig")
29 int bpf_func__null_lseek(void *ctx, int err, unsigned long _f_mode,
30  unsigned long offset, unsigned long orig)
31 {
32  fmode_t f_mode = (fmode_t)_f_mode;
33 
34  if (err)
35  return 0;
36  if (f_mode & FMODE_WRITE)
37  return 0;
38  if (offset & 1)
39  return 0;
40  if (orig == SEEK_CUR)
41  return 0;
42  return 1;
43 }
44 
45 char _license[] SEC("license") = "GPL";
46 int _version SEC("version") = LINUX_VERSION_CODE;
int int err
Definition: 5sec.c:44
const char * fmt
Definition: dso.c:193
#define FMODE_WRITE
#define SEC(NAME)
static void(* bpf_trace_printk)(const char *fmt, int fmt_size,...)
int bpf_func__null_lseek(void *ctx, int err, unsigned long _f_mode, unsigned long offset, unsigned long orig)