Re: [RFA] Fix cygwin compilation failure due to nameless LOAD_DLL_DEBUG_EVENT causes ntdll.dll to be missing

Corinna Vinschen
2013-12-18T20:54:20Z

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On Dec 18 22:01, Eli Zaretskii wrote:
> > Date: Wed, 18 Dec 2013 20:17:57 +0100
> > From: Corinna Vinschen <vinschen@redhat.com>
> >
> > > > I don't know, but I doubt it. The filenames in case of calling the
> > > > _wfopen functions are probably sent directly to the underlying WIn32
> > > > functions.
> > >
> > > I don't think they can do that, because it would mean that relative
> > > file names, "../foo", etc. are forbidden for _wfopen. The CRT
> > > functions must go through file-name normalization, so unless they
> > > detect \\?\ file names up front and refrain from any processing, the
> > > long file names will not work, because the normalization routines are
> > > where these limitations live, AFAIK.
> >
> > There's a lot of theory here. Did you actually *try* it?
>
> No. Who can afford to try everything, unless they are paying you to
> do that?

Well, it might not take much more time than musings in email...

> > I just did:
> >
> > ===========================================
> > #include <stdio.h>
> > #include <errno.h>
> >
> > int main(void)
> > {
> > FILE *fp;
> >
> > fp = _wfopen (L"\\\\?\\C:\\Windows\\System32\\ntdll.dll", L"r");
> > if (!fp)
> > printf ("_wfopen w/ long pathname fails, errno = %d\n", errno);
> > else
> > {
> > printf ("_wfopen w/ long pathname works\n");
> > fclose(fp);
> > }
> > return 0;
> > }
> > ===========================================
>
> Thanks, that's good to know. But that's just one CRT function. There
> are a gazillion of them, and I'm quite sure some use MAX_PATH of 260
> internally. Just grep the sources of the CRT functions.

Sigh.

Corinna

--
Corinna Vinschen
Cygwin Maintainer
Red Hat

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