+
+/* ordinary daemon functions use these to indicate errors */
+extern void reply_with_error (const char *fs, ...)
+ __attribute__((format (printf,1,2)));
+extern void reply_with_perror (const char *fs, ...)
+ __attribute__((format (printf,1,2)));
+
+/* daemon functions that receive files (FileIn) should call
+ * receive_file for each FileIn parameter.
+ */
+typedef int (*receive_cb) (void *opaque, const void *buf, int len);
+extern int receive_file (receive_cb cb, void *opaque);
+
+/* daemon functions that receive files (FileIn) can call this
+ * to cancel incoming transfers (eg. if there is a local error),
+ * but they MUST then call reply_with_error or reply_with_perror.
+ */
+extern void cancel_receive (void);
+
+/* daemon functions that return files (FileOut) should call
+ * reply, then send_file_* for each FileOut parameter.
+ * Note max write size if GUESTFS_MAX_CHUNK_SIZE.
+ */
+extern int send_file_write (const void *buf, int len);
+extern void send_file_end (int cancel);
+
+/* only call this if there is a FileOut parameter */
+extern void reply (xdrproc_t xdrp, char *ret);
+
+/* Helper for functions that need a root filesystem mounted.
+ * NB. Cannot be used for FileIn functions.
+ */
+#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)
+
+/* Helper for functions that need an argument ("path") that is absolute.
+ * NB. Cannot be used for FileIn functions.
+ */
+#define ABS_PATH(path,errcode) \
+ do { \
+ if ((path)[0] != '/') { \
+ reply_with_error ("%s: path must start with a / character", __func__); \
+ return (errcode); \
+ } \
+ } while (0)
+
+/* Helper for functions that need an argument ("path") that is a device.
+ * NB. Cannot be used for FileIn functions.
+ */
+#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)
+
+/* Helper for functions which need either an absolute path in the
+ * mounted filesystem, OR a /dev/ device which exists.
+ * NB. Cannot be used for FileIn functions.
+ */
+#define NEED_ROOT_OR_IS_DEVICE(path,errcode) \
+ do { \
+ if (strncmp ((path), "/dev/", 5) == 0) \
+ IS_DEVICE ((path),(errcode)); \
+ else { \
+ NEED_ROOT ((errcode)); \
+ ABS_PATH ((path),(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)
+
+/* Marks functions which are not implemented.
+ * NB. Cannot be used for FileIn functions.
+ */
+#define XXX_NOT_IMPL(errcode) \
+ do { \
+ reply_with_error ("%s: function not implemented", __func__); \
+ return (errcode); \
+ } \
+ while (0)