Add echo_daemon command

echo_daemon is a simple echo which can be used to test connectivity between the
client and daemon.

daemon/Makefile.am

@@ -36,6 +36,7 @@ guestfsd_SOURCES = \
 	dmesg.c \
 	dropcaches.c \
 	du.c \
+	echo_daemon.c \
 	ext2.c \
 	fallocate.c \
 	file.c \

daemon/echo_daemon.c

@@ -0,0 +1,73 @@
+/* libguestfs - the guestfsd daemon
+ * 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., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <config.h>
+
+#include <string.h>
+
+#include "actions.h"
+#include "daemon.h"
+
+char *
+do_echo_daemon (char *const *argv)
+{
+  char *out = NULL;
+  size_t out_len = 0;
+
+  /* Iterate over argv entries until reaching the NULL terminator */
+  while (*argv) {
+    char add_space = 0;
+
+    /* Store the end of current output */
+    size_t out_end = out_len;
+
+    /* Calculate the new output size */
+    size_t arg_len = strlen(*argv);
+    out_len += arg_len;
+
+    /* We will prepend a space if this isn't the first argument added */
+    if (NULL != out) {
+      out_len++;
+      add_space = 1;
+    }
+
+    /* Make the output buffer big enough for the string and its terminator */
+    char *out_new = realloc (out, out_len + 1);
+    if (NULL == out_new) {
+      reply_with_perror ("realloc");
+      free(out);
+      return 0;
+    }
+    out = out_new;
+
+    /* Prepend a space if required */
+    if (add_space) {
+      out[out_end++] = ' ';
+    }
+
+    /* Copy the argument to the output */
+    memcpy(&out[out_end], *argv, arg_len);
+
+    argv++;
+  }
+
+  /* NULL terminate the output */
+  out[out_len] = '\0';
+
+  return out;
+}

po/POTFILES.in

@@ -12,6 +12,7 @@ daemon/dir.c
 daemon/dmesg.c
 daemon/dropcaches.c
 daemon/du.c
+daemon/echo_daemon.c
 daemon/ext2.c
 daemon/fallocate.c
 daemon/file.c

src/MAX_PROC_NR

@@ -1 +1 @@
-194
+195

src/generator.ml

@@ -3569,6 +3569,19 @@ This loads a kernel module in the appliance.
 The kernel module must have been whitelisted when libguestfs
 was built (see C<appliance/kmod.whitelist.in> in the source).");
 
+  ("echo_daemon", (RString "output", [StringList "words"]), 195, [],
+   [InitNone, Always, TestOutput (
+     [["echo_daemon"; "This is a test"]], "This is a test"
+   )],
+   "echo arguments back to the client",
+   "\
+This command concatenate the list of C<words> passed with single spaces between
+them and returns the resulting string.
+
+You can use this command to test the connection through to the daemon.
+
+See also C<guestfs_ping_daemon>.");
+
 ]
 
 let all_functions = non_daemon_functions @ daemon_functions