2003-03-11 10:54:23

by Torsten Foertsch

Subject: [PATCH] vsscanf do not convert hex numbers starting with a non-digit

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Hi,

I found the following little bug in 2.4.19. I did not try newer kernels.

vsscanf refuses to convert a hex number starting with a nondecimal digit like:

char *buf="ff";
unsigned ff=0;
sscanf( buf, "%x", &ff ); /* fails: nothing is converted */

Here is a patch that corrects that behaviour:

- --- linux/lib/vsprintf.c 2001-10-11 20:17:22.000000000 +0200
+++ linux.patched/lib/vsprintf.c 2003-03-11 11:52:08.000000000 +0100
@@ -637,7 +637,7 @@
while (isspace(*str))
str++;

- - if (!*str || !isdigit(*str))
+ if (!*str || !(isdigit(*str) || (base==16 && isxdigit(*str))))
break;

switch(qualifier) {


Torsten
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2003-03-11 11:26:04

by Marc-Christian Petersen

Subject: Re: [PATCH] vsscanf do not convert hex numbers starting with a non-digit

On Tuesday 11 March 2003 12:02, Torsten Foertsch wrote:

Hi Torsten,


> I found the following little bug in 2.4.19. I did not try newer kernels.
> vsscanf refuses to convert a hex number starting with a nondecimal digit
> like:
> char *buf="ff";
> unsigned ff=0;
> sscanf( buf, "%x", &ff ); /* fails: nothing is converted */
>
> Here is a patch that corrects that behaviour:
>
> --- linux/lib/vsprintf.c 2001-10-11 20:17:22.000000000 +0200
> +++ linux.patched/lib/vsprintf.c 2003-03-11 11:52:08.000000000 +0100
> @@ -637,7 +637,7 @@
> while (isspace(*str))
> str++;
>
> - if (!*str || !isdigit(*str))
> + if (!*str || !(isdigit(*str) || (base==16 &&
> isxdigit(*str)))) break;
>
> switch(qualifier) {

http://marc.theaimsgroup.com/?l=linux-kernel&m=104687957102846&w=2

This fix was first posted since early 2.4.18-pre stage.

ciao, Marc