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Re: cvs pserver issue with new cygwin packages
On Thu, 11 May 2006, Charles Wilson wrote:
> Eric Blake wrote:
> > > > $ cvs co test
> > > > cannot mkdir /tmp/cvs-serv3172/.
> > > > No such file or directory
> > > This was a bug in Cygwin 1.5.19, which returned the wrong error code for
> > > creating this directory, and CVS didn't know to ignore it. Try a
> > > snapshot.
> >
> > It wasn't the 'wrong' errno, so much as a different errno than Linux
> > used in the same situation, and a bug that still exists in CVS for
> > blindly assuming that only the Linux errno will be used even on
> > non-Linux platforms. POSIX allows any number of errno
> > returns when more than one simultaneous error condition exists.
>
> Well now. That's news to me. I thought it WAS a pure cygwin bug, not a
> misinterpretation of POSIX by the cvs guys. After folks discovered the
> errno issue and it was "fixed" in the cygwin snapshots, I said "I don't
> want to clutter up the cvs sourcecode with a workaround for a bug that's
> already fixed. We'll just wait for cygwin-1.5.20"
There was some analysis of this back in February. The problem was that
Cygwin's behavior was contrary to POSIX. POSIX states:
The mkdir() function shall fail if:
[ENOENT]
A component of the path prefix specified by path does not name an
existing directory or path is an empty string.
[EEXIST]
The named file exists.
Cygwin set errno to ENOENT for somedir/., even if somedir existed. This
was just plain wrong (i.e., nothing in the above allows such behavior).
> Given Eric's explanation, that was the wrong decision. Given the
> controversy over cvs-1.11.21, I'll release an update of cvs-1.11.17 with
> a workaround for this...difference of opinion? as soon as I can. Which
> would be sooner if someone sent me a P to TC.
Chuck, the problem with adding a workaround is that there may be a
legitimate ENOENT (e.g., you call mkdir("/path/to/somedir/."), and "/path"
doesn't exist). So, even the hack you proposed in
<http://cygwin.com/ml/cygwin/2006-02/msg00175.html> will not work... The
only safe (but very inefficient) fix is to test every path component, and
ignore ENOENT only if all of them exist.
Igor
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