Guestfish feature: remote control of guestfish over a pipe.

The use case is to have a long-running guestfish process in
a shell script, and thus to avoid the overhead of starting
guestfish each time.  Do:

 eval `guestfish --listen`

 guestfish --remote somecmd
 guestfish --remote someothercmd
 guestfish --remote exit

This patch also supports having multiple guestfish processes
at the same time.

The protocol is simple XDR messages over a Unix domain socket.

1 files changed, 36 insertions, 0 deletions

diff --git a/fish/rc_protocol.x b/fish/rc_protocol.x
new file mode 100644
index 00000000..9d8f0e9f
--- /dev/null
+++ b/fish/rc_protocol.x
@@ -0,0 +1,36 @@
+/* libguestfs - guestfish remote control protocol -*- c -*-
+ * Copyright (C) 2009 Red Hat Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+typedef string str<>;
+
+struct guestfish_hello {
+  /* Client and server version strings must match exactly.  We change
+   * this protocol whenever we want to.
+   */
+  string vers<>;
+};
+
+struct guestfish_call {
+  string cmd<>;
+  str args<>;
+  bool exit_on_error;
+};
+
+struct guestfish_reply {
+  int r;			/* 0 or -1 only. */
+};