On 30Jan2017 13:49, Steve D'Aprano <steve+pyt...@pearwood.info> wrote:
This code contains a Time Of Check to Time Of Use bug:if os.path.exists(destination) raise ValueError('destination already exists') os.rename(oldname, destination) In the microsecond between checking for the existence of the destination and actually doing the rename, it is possible that another process may create the destination, resulting in data loss. Apart from keeping my fingers crossed, how should I fix this TOCTOU bug?
For files this is a problem at the Python level. At the UNIX level you can play neat games with open(2) and the various O_* modes.
however, with directories things are more cut and dry. Do you have much freedom here? What's the wider context of the question?
Cheers, Cameron Simpson <c...@zip.com.au> -- https://mail.python.org/mailman/listinfo/python-list
