The one that people came up with in the 1990s. There are quite a number of implementations to choose from. The shame of this hitting ASUS in 2023 is that this is a long-known problem and a long-since solved one. I have vague memories of grumpy posts on Usenet about this. It's that old a problem; and it has been solved for nigh on a quarter of a century.

See https://jdebp.uk/FGA/do-not-use-logrotate.html for everything from Bryan Cantrill to comments in GNU source code. (-: