launch: Make the "launched failed" message more explanatory.

Since this is the most common error seen by people who have
installation problems, buggy qemu, etc, and since no one reads the
FAQ, describe in this error message what resources are available to
debug launch problems.

Cherry picked from commit 840deea12079b05a9f588016af273843d5d6e1b8
and fixed for the stable branch.
Cherry picked from commit 58f190b2b8c507c6151fd86e6fef896f842b3e87.

1 files changed, 18 insertions, 2 deletions

diff --git a/src/launch.c b/src/launch.c
index 8f6be68d..69e2a8fb 100644
--- a/src/launch.c
+++ b/src/launch.c
@@ -989,12 +989,12 @@ launch_appliance (guestfs_h *g)
   free (buf);
 
   if (r == -1) {
-    error (g, _("guestfs_launch failed, see earlier error messages"));
+    guestfs___launch_failed_error (g);
     goto cleanup1;
   }
 
   if (size != GUESTFS_LAUNCH_FLAG) {
-    error (g, _("guestfs_launch failed, see earlier error messages"));
+    guestfs___launch_failed_error (g);
     goto cleanup1;
   }
 
@@ -1148,6 +1148,22 @@ guestfs___launch_send_progress (guestfs_h *g, int perdozen)
   }
 }
 
+/* Since this is the most common error seen by people who have
+ * installation problems, buggy qemu, etc, and since no one reads the
+ * FAQ, describe in this error message what resources are available to
+ * debug launch problems.
+ */
+void
+guestfs___launch_failed_error (guestfs_h *g)
+{
+  if (g->verbose)
+    error (g, _("guestfs_launch failed, see earlier error messages"));
+  else
+    error (g, _("guestfs_launch failed.\n"
+                "See http://libguestfs.org/guestfs-faq.1.html#debugging-libguestfs\n"
+                "and/or run 'libguestfs-test-tool'."));
+}
+
 /* Return the location of the tmpdir (eg. "/tmp") and allow users
  * to override it at runtime using $TMPDIR.
  * http://www.pathname.com/fhs/pub/fhs-2.3.html#TMPTEMPORARYFILES