IOError - cannot create file (linux daemon-invoked script)

[cassiope]

On Jan 2, 3:46 pm, Steve Holden <st... at holdenweb.com> wrote:
> cassiope wrote:
> > I have a daemon on a Linux system that supports a number of Windows
> > clients.  Among the functions is to send e-mails, which is
> > sufficiently complicated that I fork() a separate process which gets
> > setuid to a lesser user, and calls a python script which does the
> > actual formatting and emailing (the daemon is written in C).  I want
> > to save a copy of the email in a particular directory which is
> > accessible to the Windows clients via samba.
>
> > The strange thing is that even with the right user-id, I cannot seem
> > to write to the directory, getting an IOError exception.  Changing the
> > directory to world-writable fixes this.  I can confirm the uid and gid
> > for the script by having the script print these values just before
> > trying to create/write the file.  Becoming the same lesser user, I
> > have no problem writing a file to the same directory.
>
> Have you looked at the IOError's errno attribute to find out exactly why
> the Python subprocess is unable to write to the directory?

It's errno=13 ... "permission denied".

> > Is there anything that I can do to diagnose why this script is
> > failing?  For various reasons I don't want to make the directory world-
> > writable.
>
> I'd concur on that decision.
>
> > This is on a Debian "squeeze" system, with python 2.5.
>
> > Thanks for any insights!
>
> Take a closer look at the exception, that might stimulate a thought or two.
>
> regards
>  Steve
> --
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