>From bd576ed162cd3379cb945d8796d158d9563aa48e Mon Sep 17 00:00:00 2001
From: Noam Postavsky <npostavs@gmail.com>
Date: Sat, 11 Feb 2017 19:47:55 -0500
Subject: [PATCH v4 6/6] Escape NUL bytes in X selections (Bug#6991)

* lisp/term/w32-win.el (w32--set-selection):
* lisp/select.el (xselect--encode-string): Replace NUL bytes with
"\0".
* doc/emacs/killing.texi: Document new behavior.
* etc/NEWS (times): Announce it.
---
 doc/emacs/killing.texi | 4 ++++
 etc/NEWS               | 4 ++++
 lisp/select.el         | 3 +++
 lisp/term/w32-win.el   | 2 +-
 4 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/doc/emacs/killing.texi b/doc/emacs/killing.texi
index 47de053129..0b5efd04a1 100644
--- a/doc/emacs/killing.texi
+++ b/doc/emacs/killing.texi
@@ -519,6 +519,10 @@ Clipboard
 data to the clipboard manager, change the variable
 @code{x-select-enable-clipboard-manager} to @code{nil}.
 
+  Since strings containing NUL bytes are usually truncated when passed
+through the clipboard, Emacs replaces such characters with ``\0''
+before transfering them to the system's clipboard.
+
 @vindex select-enable-primary
 @findex clipboard-kill-region
 @findex clipboard-kill-ring-save
diff --git a/etc/NEWS b/etc/NEWS
index 21510fe539..281bacffd0 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -326,6 +326,10 @@ The old behaviour of using 'prin1' can be restored by customizing the
 new option 'debugger-print-function'.
 
 +++
+** NUL bytes in strings copied to the system clipboard are now
+replaced with "\0".
+
++++
 ** The new variable 'x-ctrl-keysym' has been added to the existing
 roster of X keysyms.  It can be used in combination with another
 variable of this kind to swap modifiers in Emacs.
diff --git a/lisp/select.el b/lisp/select.el
index 4849d7d515..579c5c7e2e 100644
--- a/lisp/select.el
+++ b/lisp/select.el
@@ -475,6 +475,9 @@ (defun xselect--encode-string (type str &optional can-modify)
 	   (t
 	    (error "Unknown selection type: %S" type)))))
 
+      ;; Most programs are unable to handle NUL bytes in strings.
+      (setq str (replace-regexp-in-string "\0" "\\0" str t t))
+
       (setq next-selection-coding-system nil)
       (cons type str))))
 
diff --git a/lisp/term/w32-win.el b/lisp/term/w32-win.el
index fda93884c4..be895a040d 100644
--- a/lisp/term/w32-win.el
+++ b/lisp/term/w32-win.el
@@ -396,7 +396,7 @@ (declare-function w32-selection-exists-p "w32select.c")
 ;;; Fix interface to (X-specific) mouse.el
 (defun w32--set-selection (type value)
   (if (eq type 'CLIPBOARD)
-      (w32-set-clipboard-data value)
+      (w32-set-clipboard-data (replace-regexp-in-string "\0" "\\0" value t t))
     (put 'x-selections (or type 'PRIMARY) value)))
 
 (defun w32--get-selection  (&optional type data-type)
-- 
2.11.1