1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0
2*4882a593Smuzhiyun /*
3*4882a593Smuzhiyun * bpf-script-test-prologue.c
4*4882a593Smuzhiyun * Test BPF prologue
5*4882a593Smuzhiyun */
6*4882a593Smuzhiyun #ifndef LINUX_VERSION_CODE
7*4882a593Smuzhiyun # error Need LINUX_VERSION_CODE
8*4882a593Smuzhiyun # error Example: for 4.2 kernel, put 'clang-opt="-DLINUX_VERSION_CODE=0x40200" into llvm section of ~/.perfconfig'
9*4882a593Smuzhiyun #endif
10*4882a593Smuzhiyun #define SEC(NAME) __attribute__((section(NAME), used))
11*4882a593Smuzhiyun
12*4882a593Smuzhiyun #include <uapi/linux/fs.h>
13*4882a593Smuzhiyun
14*4882a593Smuzhiyun /*
15*4882a593Smuzhiyun * If CONFIG_PROFILE_ALL_BRANCHES is selected,
16*4882a593Smuzhiyun * 'if' is redefined after include kernel header.
17*4882a593Smuzhiyun * Recover 'if' for BPF object code.
18*4882a593Smuzhiyun */
19*4882a593Smuzhiyun #ifdef if
20*4882a593Smuzhiyun # undef if
21*4882a593Smuzhiyun #endif
22*4882a593Smuzhiyun
23*4882a593Smuzhiyun #define FMODE_READ 0x1
24*4882a593Smuzhiyun #define FMODE_WRITE 0x2
25*4882a593Smuzhiyun
26*4882a593Smuzhiyun static void (*bpf_trace_printk)(const char *fmt, int fmt_size, ...) =
27*4882a593Smuzhiyun (void *) 6;
28*4882a593Smuzhiyun
29*4882a593Smuzhiyun SEC("func=null_lseek file->f_mode offset orig")
bpf_func__null_lseek(void * ctx,int err,unsigned long _f_mode,unsigned long offset,unsigned long orig)30*4882a593Smuzhiyun int bpf_func__null_lseek(void *ctx, int err, unsigned long _f_mode,
31*4882a593Smuzhiyun unsigned long offset, unsigned long orig)
32*4882a593Smuzhiyun {
33*4882a593Smuzhiyun fmode_t f_mode = (fmode_t)_f_mode;
34*4882a593Smuzhiyun
35*4882a593Smuzhiyun if (err)
36*4882a593Smuzhiyun return 0;
37*4882a593Smuzhiyun if (f_mode & FMODE_WRITE)
38*4882a593Smuzhiyun return 0;
39*4882a593Smuzhiyun if (offset & 1)
40*4882a593Smuzhiyun return 0;
41*4882a593Smuzhiyun if (orig == SEEK_CUR)
42*4882a593Smuzhiyun return 0;
43*4882a593Smuzhiyun return 1;
44*4882a593Smuzhiyun }
45*4882a593Smuzhiyun
46*4882a593Smuzhiyun char _license[] SEC("license") = "GPL";
47*4882a593Smuzhiyun int _version SEC("version") = LINUX_VERSION_CODE;
48