47 lines
1 KiB
C
47 lines
1 KiB
C
|
/*
|
||
|
|
* bpf-script-test-prologue.c
|
||
|
|
* Test BPF prologue
|
||
|
|
*/
|
||
|
|
#ifndef LINUX_VERSION_CODE
|
||
|
|
# error Need LINUX_VERSION_CODE
|
||
|
|
# error Example: for 4.2 kernel, put 'clang-opt="-DLINUX_VERSION_CODE=0x40200" into llvm section of ~/.perfconfig'
|
||
|
|
#endif
|
||
|
|
#define SEC(NAME) __attribute__((section(NAME), used))
|
||
|
|
|
||
|
|
#include <uapi/linux/fs.h>
|
||
|
|
|
||
|
|
/*
|
||
|
|
* If CONFIG_PROFILE_ALL_BRANCHES is selected,
|
||
|
|
* 'if' is redefined after include kernel header.
|
||
|
|
* Recover 'if' for BPF object code.
|
||
|
|
*/
|
||
|
|
#ifdef if
|
||
|
|
# undef if
|
||
|
|
#endif
|
||
|
|
|
||
|
|
#define FMODE_READ 0x1
|
||
|
|
#define FMODE_WRITE 0x2
|
||
|
|
|
||
|
|
static void (*bpf_trace_printk)(const char *fmt, int fmt_size, ...) =
|
||
|
|
(void *) 6;
|
||
|
|
|
||
|
|
SEC("func=null_lseek file->f_mode offset orig")
|
||
|
|
int bpf_func__null_lseek(void *ctx, int err, unsigned long _f_mode,
|
||
|
|
unsigned long offset, unsigned long orig)
|
||
|
|
{
|
||
|
|
fmode_t f_mode = (fmode_t)_f_mode;
|
||
|
|
|
||
|
|
if (err)
|
||
|
|
return 0;
|
||
|
|
if (f_mode & FMODE_WRITE)
|
||
|
|
return 0;
|
||
|
|
if (offset & 1)
|
||
|
|
return 0;
|
||
|
|
if (orig == SEEK_CUR)
|
||
|
|
return 0;
|
||
|
|
return 1;
|
||
|
|
}
|
||
|
|
|
||
|
|
char _license[] SEC("license") = "GPL";
|
||
|
|
int _version SEC("version") = LINUX_VERSION_CODE;
|