From: corinna DOT vinschen AT cityweb DOT de (Corinna Vinschen)
Subject: Re: [rdparker AT butlermfg DOT org: RE: B20 patch: UNC device path handling]
4 Nov 1998 19:10:19 -0800
Message-ID: <36410720.1DD9EBE9.cygnus.cygwin32.developers@cityweb.de>
References: <19981102194431 DOT B25468 AT cygnus DOT com>
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To: Christopher Faylor <cgf AT cygnus DOT com>,
        "Parker, Ron" <rdparker AT butlermfg DOT org>, cygwin32-developers AT cygnus DOT com

Hello Chris, hello Ron,

sorry for the fantastic line wrapping :-( 

Christopher Faylor wrote:
> 
> Corinna, do you agree with this change?
> 
> cgf
> 
> ----- Forwarded message from "Parker, Ron" <rdparker AT butlermfg DOT org> 
> [...]
> +         if (pathbuf[mount[i].pathlen] != '/' &&
> +               strncmp (mount[i].device, "\\\\.\\", 4) == 0 &&
> +               strchr(mount[i].device[mount[i].devicelen-1] + 4, '\\'))
> [...]

The above patch is incorrect, the strchr crashes:
mount[i].device[foo]	is last char in ...device
.... + 4			is the same char + 4 (e.g. 'E' instead of 'A')
--> 1st parameter to strchr is illegal ptr value.

I think, the following is ment:

+        if (pathbuf[mount[i].pathlen] != '/' &&
+            !(strncmp (mount[i].device, "\\\\.\\", 4) == 0 &&
+              strchr (mount[i].device + 4, '\\') == NULL))

Checks, if the device path has an additional `\' in it.

Another theme is: Do such UNC paths exist???
As I know, only the following device paths exist:
	\\.\X:
	\\.\physicaldriveX
	\\.\tapeX
	\\.\mailslot\foo\bar...
	\\.\pipe\pipename

Ordinary UNC paths are never beginning with \\.\, but with \\foo\...
with the exception of wide character syntax in WinNT. Then, paths are
beginning with \\?\X:\ on standard paths with drive letter and \\?\UNC\ 
on UNC paths.

If the above presentation is correct, my original patch is also correct.
If I'm wrong, I would appreciate, if somebody could explain the meaning
of \\.\UNC\

Regards,
Corinna