Re: [PATCH] (Minor) Bugfixes to vsprintf.c, vsscanf().

johan verrept (johan.verrept@pandora.be)
Thu, 18 Oct 2001 03:19:34 +0200


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johan verrept wrote:
>
> hello,
>
> minor bugfix for vsprintf.c, vsscanf did not discard whitespace in input:
> - when encoutering whitespace in fmt not followed by '%'
> - in conversion where result is ignored with '*'
>
> There is another bugfix in this, don't know from who. (picked it up with uml)
> (vsscanf used to skip two characters in the fmt for a single char in the input if not in
> conversion.)
>
> Patch against 2.4.12, I am afraid.

Attached patch is beter. Both bugs are fixed and it adds fieldwidth support for conversions with
ignored results.
Again against 2.4.12.

J.
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--- linux-2.4.12-clean/lib/vsprintf.c Sun Sep 16 20:26:10 2001
+++ linux-2.4.12-devel/lib/vsprintf.c Thu Oct 18 03:06:47 2001
@@ -525,12 +525,15 @@
for (; *fmt; fmt++) {
/* skip any white space in format */
if (isspace(*fmt)) {
+ /* space in fmt skips all space in input */
+ while (isspace(*str)) str++;
continue;
}

/* anything that is not a conversion must match exactly */
if (*fmt != '%') {
- if (*fmt++ != *str++)
+ /* Don't bump fmt because the for header will do it */
+ if (*fmt != *str++)
return num;
continue;
}
@@ -540,10 +543,25 @@
* advance both strings to next white space
*/
if (*fmt == '*') {
- while (!isspace(*fmt))
+ fmt++;
+ /* get fieldwidth */
+ field_width = 0xffffffffUL;
+ if (isdigit(*fmt))
+ field_width = skip_atoi(&fmt);
+
+ /* skip possible conversion qualifier */
+ if (*fmt == 'h' || *fmt == 'l' || *fmt == 'L' || *fmt == 'Z')
fmt++;
- while(!isspace(*str))
+
+ /* do not skip conversion char, the for loop will do this */
+
+ /* eat all whitespace before conversion! */
+ while(isspace(*str))
+ str++;
+ while(!isspace(*str) && field_width) {
+ field_width--;
str++;
+ }
continue;
}

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