/* * 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;