2 files changed, 31 insertions, 2 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index c7502104ddf..648f14a61e4 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,5 +1,11 @@
 2012-12-23  Eli Zaretskii  <eliz@gnu.org>
 
+        * w32.c (acl_set_file): If setting the file security descriptor
+        fails, and the new DACL is identical to the existing one, silently
+        return success.  This fixes problems for users backing up their
+        own files without having the necessary privileges for setting
+        security descriptors.
+
         * w32proc.c (reader_thread): Do not index fd_info[] with negative
         values.
         (reader_thread): Exit when cp->status becomes STATUS_READ_ERROR
diff --git a/src/w32.c b/src/w32.c
index 47b950668b0..9ebc97088d0 100644
--- a/src/w32.c
+++ b/src/w32.c
@@ -4876,8 +4876,31 @@ acl_set_file (const char *fname, acl_type_t type, acl_t acl)
       retval = 0;
       errno = e;
     }
-  else if (err == ERROR_INVALID_OWNER)
-    errno = EPERM;
+  else if (err == ERROR_INVALID_OWNER || err == ERROR_NOT_ALL_ASSIGNED)
+    {
+      /* Maybe the requested ACL and the one the file already has are
+         identical, in which case we can silently ignore the
+         failure.  (And no, Windows doesn't.)  */
+      acl_t current_acl = acl_get_file (fname, ACL_TYPE_ACCESS);
+
+      errno = EPERM;
+      if (current_acl)
+        {
+          char *acl_from = acl_to_text (current_acl, NULL);
+          char *acl_to = acl_to_text (acl, NULL);
+
+          if (acl_from && acl_to && xstrcasecmp (acl_from, acl_to) == 0)
+            {
+              retval = 0;
+              errno = e;
+            }
+          if (acl_from)
+            acl_free (acl_from);
+          if (acl_to)
+            acl_free (acl_to);
+          acl_free (current_acl);
+        }
+    }
   else if (err == ERROR_FILE_NOT_FOUND || err == ERROR_PATH_NOT_FOUND)
     errno = ENOENT;