+extern void reply_with_perror (const char *fs, ...);
+extern void reply (xdrproc_t xdrp, char *ret);
+
+#define NEED_ROOT(errcode) \
+ do { \
+ if (!root_mounted) { \
+ reply_with_error ("%s: you must call 'mount' first to mount the root filesystem", __func__); \
+ return (errcode); \
+ } \
+ } \
+ while (0)
+
+#define ABS_PATH(path,errcode) \
+ do { \
+ if ((path)[0] != '/') { \
+ reply_with_error ("%s: path must start with a / character", __func__); \
+ return (errcode); \
+ } \
+ } while (0)
+
+#define IS_DEVICE(path,errcode) \
+ do { \
+ struct stat statbuf; \
+ if (strncmp ((path), "/dev/", 5) != 0) { \
+ reply_with_error ("%s: %s: expecting a device name", __func__, (path)); \
+ return (errcode); \
+ } \
+ if (stat ((path), &statbuf) == -1) { \
+ reply_with_perror ("%s: %s", __func__, (path)); \
+ return (errcode); \
+ } \
+ } while (0)
+
+/* NB:
+ * (1) You must match CHROOT_IN and CHROOT_OUT even along error paths.
+ * (2) You must not change directory! cwd must always be "/", otherwise
+ * we can't escape our own chroot.
+ * (3) All paths specified must be absolute.
+ * (4) CHROOT_OUT does not affect errno.
+ */
+#define CHROOT_IN chroot ("/sysroot");
+#define CHROOT_OUT \
+ do { int old_errno = errno; chroot ("."); errno = old_errno; } while (0)
+
+#define XXX_NOT_IMPL(errcode) \
+ do { \
+ reply_with_error ("%s: function not implemented", __func__); \
+ return (errcode); \
+ } \
+ while (0)