(tramp-open-connection-setup-interactive-shell): Flush cache, and

restart `tramp-maybe-open-connection' when the remote system has
been changed. Throw 'uname-changed event.
(tramp-maybe-open-connection): Catch it.

2 files changed, 179 insertions, 165 deletions

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index 0d3d3a40638..6f7b1ce01b2 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -29,6 +29,10 @@
         modification time of the connection buffer.
         (tramp-sh-file-name-handler): Reset `tramp-locked' in case of
         error.
+        (tramp-open-connection-setup-interactive-shell): Flush cache, and
+        restart `tramp-maybe-open-connection' when the remote system has
+        been changed. Throw 'uname-changed event.
+        (tramp-maybe-open-connection): Catch it.
 
         * net/tramp-cmds.el (tramp-cleanup-all-connections): Reset
         `tramp-locked'.
diff --git a/lisp/net/tramp.el b/lisp/net/tramp.el
index 943a7a66b55..5918db6df4a 100644
--- a/lisp/net/tramp.el
+++ b/lisp/net/tramp.el
@@ -5846,7 +5846,8 @@ process to set up.  VEC specifies the connection."
 
   ;; Check whether the output of "uname -sr" has been changed.  If
   ;; yes, this is a strong indication that we must expire all
-  ;; connection properties.
+  ;; connection properties.  We start again with
+  ;; `tramp-maybe-open-connection', it will be catched there.
   (tramp-message vec 5 "Checking system information")
   (let ((old-uname (tramp-get-connection-property vec "uname" nil))
         (new-uname
@@ -5854,12 +5855,20 @@ process to set up.  VEC specifies the connection."
           vec "uname"
           (tramp-send-command-and-read vec "echo \\\"`uname -sr`\\\""))))
     (when (and (stringp old-uname) (not (string-equal old-uname new-uname)))
-      (funcall (symbol-function 'tramp-cleanup-connection) vec)
-      (signal
-       'quit
-       (list (format
-              "Connection reset, because remote host changed from `%s' to `%s'"
-              old-uname new-uname)))))
+      (with-current-buffer (tramp-get-debug-buffer vec)
+        ;; Keep the debug buffer
+        (rename-buffer " *temp*" 'unique)
+        (funcall (symbol-function 'tramp-cleanup-connection) vec)
+        (if (= (point-min) (point-max))
+            (kill-buffer nil)
+          (rename-buffer (tramp-debug-buffer-name vec) 'unique))
+        ;; We call `tramp-get-buffer' in order to keep the debug buffer.
+        (tramp-get-buffer vec)
+        (tramp-message
+         vec 3
+         "Connection reset, because remote host changed from `%s' to `%s'"
+         old-uname new-uname)
+        (throw 'uname-changed (tramp-maybe-open-connection vec)))))
 
   ;; Check whether the remote host suffers from buggy
   ;; `send-process-string'.  This is known for FreeBSD (see comment in
@@ -6222,167 +6231,168 @@ Gateway hops are already opened."
   "Maybe open a connection VEC.
 Does not do anything if a connection is already open, but re-opens the
 connection if a previous connection has died for some reason."
-  (let ((p (tramp-get-connection-process vec))
-        (process-environment (copy-sequence process-environment)))
-
-    ;; If too much time has passed since last command was sent, look
-    ;; whether process is still alive.  If it isn't, kill it.  When
-    ;; using ssh, it can sometimes happen that the remote end has hung
-    ;; up but the local ssh client doesn't recognize this until it
-    ;; tries to send some data to the remote end.  So that's why we
-    ;; try to send a command from time to time, then look again
-    ;; whether the process is really alive.
-    (condition-case nil
-        (when (and (> (tramp-time-diff
-                       (current-time)
-                       (tramp-get-connection-property
-                        p "last-cmd-time" '(0 0 0)))
-                      60)
-                   p (processp p) (memq (process-status p) '(run open)))
-          (tramp-send-command vec "echo are you awake" t t)
-          (unless (and (memq (process-status p) '(run open))
-                       (tramp-wait-for-output p 10))
-            ;; The error will be catched locally.
-            (tramp-error vec 'file-error "Awake did fail")))
-      (file-error
-       (tramp-flush-connection-property vec)
-       (tramp-flush-connection-property p)
-       (delete-process p)
-       (setq p nil)))
-
-    ;; New connection must be opened.
-    (unless (and p (processp p) (memq (process-status p) '(run open)))
-
-      ;; We call `tramp-get-buffer' in order to get a debug buffer for
-      ;; messages from the beginning.
-      (tramp-get-buffer vec)
-      (if (zerop (length (tramp-file-name-user vec)))
+  (catch 'uname-changed
+    (let ((p (tramp-get-connection-process vec))
+          (process-environment (copy-sequence process-environment)))
+
+      ;; If too much time has passed since last command was sent, look
+      ;; whether process is still alive.  If it isn't, kill it.  When
+      ;; using ssh, it can sometimes happen that the remote end has
+      ;; hung up but the local ssh client doesn't recognize this until
+      ;; it tries to send some data to the remote end.  So that's why
+      ;; we try to send a command from time to time, then look again
+      ;; whether the process is really alive.
+      (condition-case nil
+          (when (and (> (tramp-time-diff
+                         (current-time)
+                         (tramp-get-connection-property
+                          p "last-cmd-time" '(0 0 0)))
+                        60)
+                     p (processp p) (memq (process-status p) '(run open)))
+            (tramp-send-command vec "echo are you awake" t t)
+            (unless (and (memq (process-status p) '(run open))
+                         (tramp-wait-for-output p 10))
+              ;; The error will be catched locally.
+              (tramp-error vec 'file-error "Awake did fail")))
+        (file-error
+         (tramp-flush-connection-property vec)
+         (tramp-flush-connection-property p)
+         (delete-process p)
+         (setq p nil)))
+
+      ;; New connection must be opened.
+      (unless (and p (processp p) (memq (process-status p) '(run open)))
+
+        ;; We call `tramp-get-buffer' in order to get a debug buffer for
+        ;; messages from the beginning.
+        (tramp-get-buffer vec)
+        (if (zerop (length (tramp-file-name-user vec)))
+            (tramp-message
+             vec 3 "Opening connection for %s using %s..."
+             (tramp-file-name-host vec)
+             (tramp-file-name-method vec))
           (tramp-message
-           vec 3 "Opening connection for %s using %s..."
+           vec 3 "Opening connection for %s@%s using %s..."
+           (tramp-file-name-user vec)
            (tramp-file-name-host vec)
-           (tramp-file-name-method vec))
-        (tramp-message
-         vec 3 "Opening connection for %s@%s using %s..."
-         (tramp-file-name-user vec)
-         (tramp-file-name-host vec)
-         (tramp-file-name-method vec)))
-
-      ;; Start new process.
-      (when (and p (processp p))
-        (delete-process p))
-      (setenv "TERM" tramp-terminal-type)
-      (setenv "LC_ALL" "C")
-      (setenv "PROMPT_COMMAND")
-      (setenv "PS1" "$ ")
-      (let* ((target-alist (tramp-compute-multi-hops vec))
-             (process-connection-type tramp-process-connection-type)
-             (process-adaptive-read-buffering nil)
-             (coding-system-for-read nil)
-             ;; This must be done in order to avoid our file name handler.
-             (p (let ((default-directory
-                        (tramp-compat-temporary-file-directory)))
-                  (start-process
-                   (or (tramp-get-connection-property vec "process-name" nil)
-                       (tramp-buffer-name vec))
-                   (tramp-get-connection-buffer vec)
-                   tramp-encoding-shell)))
-             (first-hop t))
+           (tramp-file-name-method vec)))
+
+        ;; Start new process.
+        (when (and p (processp p))
+          (delete-process p))
+        (setenv "TERM" tramp-terminal-type)
+        (setenv "LC_ALL" "C")
+        (setenv "PROMPT_COMMAND")
+        (setenv "PS1" "$ ")
+        (let* ((target-alist (tramp-compute-multi-hops vec))
+               (process-connection-type tramp-process-connection-type)
+               (process-adaptive-read-buffering nil)
+               (coding-system-for-read nil)
+               ;; This must be done in order to avoid our file name handler.
+               (p (let ((default-directory
+                          (tramp-compat-temporary-file-directory)))
+                    (start-process
+                     (or (tramp-get-connection-property vec "process-name" nil)
+                         (tramp-buffer-name vec))
+                     (tramp-get-connection-buffer vec)
+                     tramp-encoding-shell)))
+               (first-hop t))
 
-        (tramp-message
-         vec 6 "%s" (mapconcat 'identity (process-command p) " "))
-
-        ;; Check whether process is alive.
-        (set-process-sentinel p 'tramp-process-sentinel)
-        (tramp-set-process-query-on-exit-flag p nil)
-        (tramp-message vec 3 "Waiting 60s for local shell to come up...")
-        (tramp-barf-if-no-shell-prompt
-         p 60 "Couldn't find local shell prompt %s" tramp-encoding-shell)
-
-        ;; Now do all the connections as specified.
-        (while target-alist
-          (let* ((hop (car target-alist))
-                 (l-method (tramp-file-name-method hop))
-                 (l-user (tramp-file-name-user hop))
-                 (l-host (tramp-file-name-host hop))
-                 (l-port nil)
-                 (login-program
-                  (tramp-get-method-parameter l-method 'tramp-login-program))
-                 (login-args
-                  (tramp-get-method-parameter l-method 'tramp-login-args))
-                 (gw-args
-                  (tramp-get-method-parameter l-method 'tramp-gw-args))
-                 (gw (tramp-get-file-property hop "" "gateway" nil))
-                 (g-method (and gw (tramp-file-name-method gw)))
-                 (g-user (and gw (tramp-file-name-user gw)))
-                 (g-host (and gw (tramp-file-name-host gw)))
-                 (command login-program)
-                 ;; We don't create the temporary file.  In fact, it
-                 ;; is just a prefix for the ControlPath option of
-                 ;; ssh; the real temporary file has another name, and
-                 ;; it is created and protected by ssh.  It is also
-                 ;; removed by ssh, when the connection is closed.
-                 (tmpfile
-                  (tramp-set-connection-property
-                   p "temp-file"
-                   (make-temp-name
-                    (expand-file-name
-                     tramp-temp-name-prefix
-                     (tramp-compat-temporary-file-directory)))))
-                 spec)
-
-            ;; Add gateway arguments if necessary.
-            (when (and gw gw-args)
-              (setq login-args (append login-args gw-args)))
-
-            ;; Check for port number.  Until now, there's no need for handling
-            ;; like method, user, host.
-            (when (string-match tramp-host-with-port-regexp l-host)
-              (setq l-port (match-string 2 l-host)
-                    l-host (match-string 1 l-host)))
-
-            ;; Set variables for computing the prompt for reading password.
-            ;; They can also be derived from a gatewy.
-            (setq tramp-current-method (or g-method l-method)
-                  tramp-current-user   (or g-user   l-user)
-                  tramp-current-host   (or g-host   l-host))
-
-            ;; Replace login-args place holders.
-            (setq
-             l-host (or l-host "")
-             l-user (or l-user "")
-             l-port (or l-port "")
-             spec `((?h . ,l-host) (?u . ,l-user) (?p . ,l-port)
-                    (?t . ,tmpfile))
-             command
-             (concat
-              command " "
-              (mapconcat
-               '(lambda (x)
-                  (setq x (mapcar '(lambda (y) (format-spec y spec)) x))
-                  (unless (member "" x) (mapconcat 'identity x " ")))
-               login-args " ")
-              ;; String to detect failed connection.  Every single word must
-              ;; be enclosed with '\"'; otherwise it is detected
-              ;; during connection setup.
-              ;; Local shell could be a Windows COMSPEC.  It doesn't know
-              ;; the ";" syntax, but we must exit always for `start-process'.
-              ;; "exec" does not work either.
-              (if first-hop
-                  " && exit || exit"
-                "; echo \"Tramp\" \"connection\" \"closed\"; sleep 1"))
-             ;; We don't reach a Windows shell.  Could be initial only.
-             first-hop nil)
-
-            ;; Send the command.
-            (tramp-message vec 3 "Sending command `%s'" command)
-            (tramp-send-command vec command t t)
-            (tramp-process-actions p vec tramp-actions-before-shell 60)
-            (tramp-message vec 3 "Found remote shell prompt on `%s'" l-host))
-          ;; Next hop.
-          (setq target-alist (cdr target-alist)))
-
-        ;; Make initial shell settings.
-        (tramp-open-connection-setup-interactive-shell p vec)))))
+          (tramp-message
+           vec 6 "%s" (mapconcat 'identity (process-command p) " "))
+
+          ;; Check whether process is alive.
+          (set-process-sentinel p 'tramp-process-sentinel)
+          (tramp-set-process-query-on-exit-flag p nil)
+          (tramp-message vec 3 "Waiting 60s for local shell to come up...")
+          (tramp-barf-if-no-shell-prompt
+           p 60 "Couldn't find local shell prompt %s" tramp-encoding-shell)
+
+          ;; Now do all the connections as specified.
+          (while target-alist
+            (let* ((hop (car target-alist))
+                   (l-method (tramp-file-name-method hop))
+                   (l-user (tramp-file-name-user hop))
+                   (l-host (tramp-file-name-host hop))
+                   (l-port nil)
+                   (login-program
+                    (tramp-get-method-parameter l-method 'tramp-login-program))
+                   (login-args
+                    (tramp-get-method-parameter l-method 'tramp-login-args))
+                   (gw-args
+                    (tramp-get-method-parameter l-method 'tramp-gw-args))
+                   (gw (tramp-get-file-property hop "" "gateway" nil))
+                   (g-method (and gw (tramp-file-name-method gw)))
+                   (g-user (and gw (tramp-file-name-user gw)))
+                   (g-host (and gw (tramp-file-name-host gw)))
+                   (command login-program)
+                   ;; We don't create the temporary file.  In fact, it
+                   ;; is just a prefix for the ControlPath option of
+                   ;; ssh; the real temporary file has another name, and
+                   ;; it is created and protected by ssh.  It is also
+                   ;; removed by ssh, when the connection is closed.
+                   (tmpfile
+                    (tramp-set-connection-property
+                     p "temp-file"
+                     (make-temp-name
+                      (expand-file-name
+                       tramp-temp-name-prefix
+                       (tramp-compat-temporary-file-directory)))))
+                   spec)
+
+              ;; Add gateway arguments if necessary.
+              (when (and gw gw-args)
+                (setq login-args (append login-args gw-args)))
+
+              ;; Check for port number.  Until now, there's no need
+              ;; for handling like method, user, host.
+              (when (string-match tramp-host-with-port-regexp l-host)
+                (setq l-port (match-string 2 l-host)
+                      l-host (match-string 1 l-host)))
+
+              ;; Set variables for computing the prompt for reading
+              ;; password.  They can also be derived from a gatewy.
+              (setq tramp-current-method (or g-method l-method)
+                    tramp-current-user   (or g-user   l-user)
+                    tramp-current-host   (or g-host   l-host))
+
+              ;; Replace login-args place holders.
+              (setq
+               l-host (or l-host "")
+               l-user (or l-user "")
+               l-port (or l-port "")
+               spec `((?h . ,l-host) (?u . ,l-user) (?p . ,l-port)
+                      (?t . ,tmpfile))
+               command
+               (concat
+                command " "
+                (mapconcat
+                 '(lambda (x)
+                    (setq x (mapcar '(lambda (y) (format-spec y spec)) x))
+                    (unless (member "" x) (mapconcat 'identity x " ")))
+                 login-args " ")
+                ;; String to detect failed connection.  Every single
+                ;; word must be enclosed with '\"'; otherwise it is
+                ;; detected during connection setup.
+                ;; Local shell could be a Windows COMSPEC.  It doesn't
+                ;; know the ";" syntax, but we must exit always for
+                ;; `start-process'.  "exec" does not work either.
+                (if first-hop
+                    " && exit || exit"
+                  "; echo \"Tramp\" \"connection\" \"closed\"; sleep 1"))
+               ;; We don't reach a Windows shell.  Could be initial only.
+               first-hop nil)
+
+              ;; Send the command.
+              (tramp-message vec 3 "Sending command `%s'" command)
+              (tramp-send-command vec command t t)
+              (tramp-process-actions p vec tramp-actions-before-shell 60)
+              (tramp-message vec 3 "Found remote shell prompt on `%s'" l-host))
+            ;; Next hop.
+            (setq target-alist (cdr target-alist)))
+
+          ;; Make initial shell settings.
+          (tramp-open-connection-setup-interactive-shell p vec))))))
 
 (defun tramp-send-command (vec command &optional neveropen nooutput)
   "Send the COMMAND to connection VEC.