When atomically replacing files, copy attributes

lib/ansible/module_common.py

@@ -594,6 +594,20 @@ class AnsibleModule(object):
             self.fail_json(msg='Could not make backup of %s to %s: %s' % (fn, backupdest, e))
         return backupdest
 
+    def atomic_replace(self, src, dest):
+        '''atomically replace dest with src, copying attributes from dest'''
+        st = os.stat(dest)
+        os.chmod(src, st.st_mode & 07777)
+        try:
+            os.chown(src, st.st_uid, st.st_gid)
+        except OSError, e:
+            if e.errno != errno.EPERM:
+                raise
+        if self.selinux_enabled():
+            context = self.selinux_context(dest)
+            self.set_context_if_different(src, context, False)
+        os.rename(src, dest)
+
 
 # == END DYNAMICALLY INSERTED CODE ===
 

library/authorized_key

@@ -125,13 +125,7 @@ def writekeys(module, filename, keys):
     except IOError, e:
         module.fail_json(msg="Failed to write to file %s: %s" % (tmp_path, str(e)))
     f.close()
-    try:
-        shutil.copyfile(tmp_path, filename)
-        os.unlink(tmp_path)
-    except IOError, e:
-        module.fail_json(msg="Failed to copy temp file to %s: %s" % (filename, str(e)))
-    except OSError, e:
-        module.fail_json(msg="Failed to remove temp file: %s" % str(e))
+    module.atomic_replace(tmp_path, filename)
 
 def enforce_state(module, params):
     """

library/copy

@@ -114,7 +114,7 @@ def main():
             # might be an issue with exceeding path length
             dest_tmp = "%s.%s.%s.tmp" % (dest,os.getpid(),time.time())
             shutil.copyfile(src, dest_tmp)
-            shutil.move(dest_tmp, dest)
+            module.atomic_replace(dest_tmp, dest)
         except shutil.Error:
             module.fail_json(msg="failed to copy: %s and %s are the same" % (src, dest))
         except IOError: