linux-kernel - [PATCH] Fix isspace() and other ctype.h functions to ignore chars 128-255

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Message-Id: <DF41BB75-679F-4B6A-90F3-77DF228B6D3D@mac.com>
Date:	Wed, 7 Nov 2007 05:56:05 -0500
From:	Kyle Moffett <mrlinuxman@....com>
To:	Linus Torvalds <torvalds@...ux-foundation.org>
Cc:	"Ahmed S. Darwish" <darwish.07@...il.com>,
	Adrian Bunk <bunk@...nel.org>,
	Casey Schaufler <casey@...aufler-ca.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	linux-security-module@...r.kernel.org,
	LKML Kernel <linux-kernel@...r.kernel.org>
Subject: [PATCH] Fix isspace() and other ctype.h functions to ignore chars 128-255

Originally isspace() and other similar functions in ctype.h ignored  
any character with the high bit set; however this was changed during  
the linux 2.1 days to map Latin-1.  As following Latin-1 will most  
likely break UTF-8 any any *other* encoding that is backwards- 
compatible with 7-bit-ASCII, change ctype.c to ignore such characters  
completely (the way they were before).  Linus seems to think this is  
a good thing, and he's the one that wrote the code in the first place.

Signed-off-by: Kyle Moffett <mrlinuxman@....com>

---

On Nov 06, 2007, at 10:53:08, Linus Torvalds wrote:
> On Tue, 6 Nov 2007, Kyle Moffett wrote:
>> Personally I think that isspace() accepting character 0xA0 is a bug
>
> I think I agree with you. As far as the kernel is concerned,  
> "isspace()" should just accept the obvious spaces (hardspace, tab,  
> newline), and *perhaps* the VT/FF kind of things.
>
> You should realize that the kernel <ctype.h> thing is *ancient*.  
> It's basically there from v0.01, and while the really original one  
> (I just checked) had all the non-ascii characters not trigger  
> anything, it was converted to be latin1 in the 2.1.x timeframe.
>
> That's a *loong* time ago. Way before UTF-8 and other things were  
> really common.
>
> So we should probably just make all the upper 128 bytes go back to  
> "don't trigger anything in ctype.h" - they'd not be spaces, but  
> they'd not be control characters or anything else either.


View attachment "fix-isspace-patch.txt" of type "text/plain" (1362 bytes)