OverrideImmutableRename() new file inherits immutable flag of old

When renaming a file using the OverrideImmutableRename() function, the
immutable bit is temporarily removed from both the old and new (if it
already exists). The immutable bit is then inherited from old to new
file.

Signed-off-by: Lars Erik Wik <lars.erik.wik@northern.tech>

Author: larsewi

libpromises/override_fsattrs.c

@@ -168,22 +168,26 @@ bool OverrideImmutableRename(
     assert(old_filename != NULL);
     assert(new_filename != NULL);
 
-    bool is_immutable;
-    FSAttrsResult res =
-        TemporarilyClearImmutableBit(new_filename, override, &is_immutable);
+    bool new_is_immutable;
+    TemporarilyClearImmutableBit(new_filename, override, &new_is_immutable);
+
+    bool old_is_immutable;
+    FSAttrsResult res_old = TemporarilyClearImmutableBit(
+        old_filename, override, &old_is_immutable);
 
     if (rename(old_filename, new_filename) == -1)
     {
         Log(LOG_LEVEL_ERR,
-            "Failed to replace original file '%s' with copy '%s'",
+            "Failed to replace original file '%s' with copy '%s': %s",
             new_filename,
-            old_filename);
+            old_filename,
+            GetErrorStr());
         unlink(old_filename);
         return false;
     }
 
     ResetTemporarilyClearedImmutableBit(
-        new_filename, override, res, is_immutable);
+        new_filename, override, res_old, old_is_immutable);
 
     return true;
 }