From bdc373bf456de464b44836b11826705c0aef70b1 Mon Sep 17 00:00:00 2001
From: Rasmus Pank Roulund <emacs@pank.eu>
Date: Wed, 10 Dec 2014 17:47:53 +0100
Subject: [PATCH] (ange-ftp-switches-ok): Disallow flags causing trouble with
 ls over ftp.

Fixes: debbugs:19192

* net/ange-ftp.el (ange-ftp-switches-ok): Disallow flags causing
trouble with ls over ftp.  These flags result in ls returning no
output, causing Tramp-breakage.
---
 lisp/ChangeLog       |  6 ++++++
 lisp/net/ange-ftp.el | 20 ++++++++++++++------
 2 files changed, 20 insertions(+), 6 deletions(-)

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index 454ee000c9a..53c03e0f106 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,9 @@
+2014-12-10  Rasmus Pank Roulund  <emacs@pank.eu>
+
+	* net/ange-ftp.el (ange-ftp-switches-ok): Disallow flags causing
+	trouble with ls over ftp.  These flags result in ls returning no
+	output, causing Tramp-breakage.  (bug#19192)
+
 2014-12-10  Andreas Schwab  <schwab@suse.de>
 
 	* files.el (file-tree-walk): Use file-name-as-directory
diff --git a/lisp/net/ange-ftp.el b/lisp/net/ange-ftp.el
index d7632ed5e1b..db79c0d6675 100644
--- a/lisp/net/ange-ftp.el
+++ b/lisp/net/ange-ftp.el
@@ -2831,16 +2831,24 @@ match subdirectories as well.")
 		      files ange-ftp-files-hashtable)))
 
 (defun ange-ftp-switches-ok (switches)
-  "Return SWITCHES (a string) if suitable for our use."
+  "Return SWITCHES (a string) if suitable for use with ls over ftp."
   (and (stringp switches)
-       ;; We allow the A switch, which lists all files except "." and
-       ;; "..".  This is OK because we manually insert these entries
-       ;; in the hash table.
+       ;; We allow the --almost-all switch, which lists all files
+       ;; except "." and "..".  This is OK because we manually
+       ;; insert these entries in the hash table.
        (string-match
-	"--\\(almost-\\)?all\\>\\|\\(\\`\\| \\)-[[:alpha:]]*[aA]" switches)
+        "--\\(almost-\\)?all\\>\\|\\(\\`\\| \\)-[[:alpha:]]*[aA]"
+        switches)
+       ;; Disallow other long flags except --(almost-)all.
+       (not (string-match "\\(\\`\\| \\)--\\w+"
+                          (replace-regexp-in-string
+                           "--\\(almost-\\)?all\\>" ""
+                           switches)))
+       ;; Must include 'l'.
        (string-match "\\(\\`\\| \\)-[[:alpha:]]*l" switches)
+       ;; Disallow recursive flag.
        (not (string-match
-	     "--recursive\\>\\|\\(\\`\\| \\)-[[:alpha:]]*R" switches))
+             "\\(\\`\\| \\)-[[:alpha:]]*R" switches))
        switches))
 
 (defun ange-ftp-get-files (directory &optional no-error)
-- 
2.39.2