Writing to a file atomically without renaming

[nomis80]

Hello monk masters,

For the sake of exception safety, I want to write to a file atomically. In the process of writing to a file exceptions could be thrown if for example there is no more disk space. I know of the module IO::AtomicFile, which, it would seem, should make me happy.

However, this module uses the old trick of writing to a temporary file and then renaming it. This is nice for atomicity, but causes one problem: it clobbers the file attributes like owner and permissions. For example, I have this file:

-rw--w---- 1 user1 group1 ... filename

Let's assume I am running my program as "user2", which is a member of "group1". If I write to a temporary file and then move it, the owner of the file will have changed to "user2". Only root can change the owner of a file, so I'm stuck.

Is there a way to write to a file atomically without using rename()?

Thanks!