Added `comint-password-function' hook

* etc/NEWS:
* lisp/comint.el (comint-password-function): New variable.
  (comint-send-invisible): Use it.
* test/lisp/comint-tests.el (comint-test-no-password-function,
  comint-test-password-function-with-value,
  comint-test-password-function-with-nil): Test new variable.

1 files changed, 14 insertions, 2 deletions

diff --git a/lisp/comint.el b/lisp/comint.el
index 4bb43670354..c06a63fbd24 100644
--- a/lisp/comint.el
+++ b/lisp/comint.el
@@ -2356,6 +2356,13 @@ a buffer local variable."
 ;; saved -- typically passwords to ftp, telnet, or somesuch.
 ;; Just enter m-x comint-send-invisible and type in your line.
 
+(defvar comint-password-function nil
+  "Abnormal hook run when prompted for a password.
+This function gets one argument, a string containing the prompt.
+It may return a string containing the password, or nil if normal
+password prompting should occur.")
+(make-variable-buffer-local 'comint-password-function)
+
 (defun comint-send-invisible (&optional prompt)
   "Read a string without echoing.
 Then send it to the process running in the current buffer.
@@ -2370,8 +2377,13 @@ Security bug: your string can still be temporarily recovered with
            (format "(In buffer %s) "
                    (current-buffer)))))
     (if proc
-        (let ((str (read-passwd (concat prefix
-                                        (or prompt "Non-echoed text: ")))))
+        (let ((prefix-prompt (concat prefix
+                                     (or prompt "Non-echoed text: ")))
+              str)
+          (when comint-password-function
+            (setq str (funcall comint-password-function prefix-prompt)))
+          (unless str
+            (setq str (read-passwd prefix-prompt)))
           (if (stringp str)
               (progn
                 (comint-snapshot-last-prompt)