char *crypt_loop_backing_file(const char *loop);
int crypt_loop_device(const char *loop);
int crypt_loop_attach(char **loop, const char *file, int offset,
char *crypt_loop_backing_file(const char *loop);
int crypt_loop_device(const char *loop);
int crypt_loop_attach(char **loop, const char *file, int offset,