* net/tramp-adb.el (tramp-adb-maybe-open-connection): Cache,

whether the "su" command is available on the device.

2 files changed, 15 insertions, 1 deletions

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index 8b6ffeed01d..a19ebaf473f 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,8 @@
+2013-03-03  Michael Albinus  <michael.albinus@gmx.de>
+
+        * net/tramp-adb.el (tramp-adb-maybe-open-connection): Cache,
+        whether the "su" command is available on the device.
+
 2013-03-01  Michael Albinus  <michael.albinus@gmx.de>
 
         * net/tramp-adb.el (tramp-adb-prompt): Extend regexp.
diff --git a/lisp/net/tramp-adb.el b/lisp/net/tramp-adb.el
index 910356fbb6c..2d683a4d3d2 100644
--- a/lisp/net/tramp-adb.el
+++ b/lisp/net/tramp-adb.el
@@ -1074,6 +1074,13 @@ connection if a previous connection has died for some reason."
          (host (tramp-file-name-host vec))
          (user (tramp-file-name-user vec))
          (devices (mapcar 'cadr (tramp-adb-parse-device-names nil))))
+
+    ;; Maybe we know already that "su" is not supported.  We cannot
+    ;; use a connection property, because we have not checked yet
+    ;; whether it is still the same device.
+    (when (and user (not (tramp-get-file-property vec "" "su-command-p" t)))
+      (tramp-error vec 'file-error "Cannot switch to user `%s'" user))
+
     (unless
         (and p (processp p) (memq (process-status p) '(run open)))
       (save-match-data
@@ -1133,7 +1140,9 @@ connection if a previous connection has died for some reason."
               (tramp-adb-send-command vec (format "su %s" user))
               (unless (zerop (tramp-adb-command-exit-status vec nil))
                 (delete-process p)
-                (tramp-error vec 'file-error "Cannot switch to user %s" user)))
+                (tramp-set-file-property vec "" "su-command-p" nil)
+                (tramp-error
+                 vec 'file-error "Cannot switch to user `%s'" user)))
 
             ;; Set "remote-path" connection property.  This is needed
             ;; for eshell.