So here's the function in question (thanks for giving me the needed kick in the bats to go looking at it, gerritv - it was more straightforward than I feared):
Code:
def safe_write(filename, data, mode=0o644):
import os, tempfile
fd, fn = tempfile.mkstemp(dir=os.path.dirname(filename), prefix=os.path.basename(filename))
try:
os.write(fd, data)
os.close(fd)
fd = None
os.rename(fn, filename)
os.chmod(filename, mode)
finally:
if fd is not None:
os.close(fd)
if os.path.isfile(fn):
os.unlink(fn)
( from /usr/lib/python2.7/dist-packages/gladevcp/hal_sourceview.py )
It looks like the problem has nothing to do with creating the file... it's the chmod that kills it. Trying to chmod a file on a root-owned smb share as a non-root user gives "Operation not permitted" (and just silently fails when root tries it).
The question is, where do I go from here?
Just commenting out the chmod
seems to make things work (the only apparent difference being that the files in local - permission-aware - filesystems end up as rw/-/- instead of rw/r/r), but that sets me up for trouble if an update comes along & breaks my "fix", and does nothing to resolve the issue for anyone else who finds themselves in the same mess.
Would it possible (or advisable) to just silently fail if the chmod fails, instead of throwing a tantrum? Does python allow nested try/catch blocks like that?
And should there be more checking done before unlinking (potentially deleting) the original file at the end, if this is going to be called "safe_write()"?
Any thoughts?
Or is there someone more qualified (read: even
slightly qualified) that I can pass this off to?
-Bats
