linux-kernel - [PATCH] vscnprintf/scnprintf return incorrent len

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Date:	Wed, 11 Mar 2009 11:43:37 +0100
From:	Vitaly Mayatskikh <v.mayatskih@...il.com>
To:	linux-kernel@...r.kernel.org
Cc:	Linus Torvalds <torvalds@...ux-foundation.org>
Subject: [PATCH] vscnprintf/scnprintf return incorrent len

(v)scnprintf says it should return 0 when size is 0, but doesn't do
so. Also size_t is unsigned, it can't be less then 0. Fix the code and
comments.

diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index 0fbd012..8e75c7e 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -947,7 +947,7 @@ EXPORT_SYMBOL(vsnprintf);
  * @args: Arguments for the format string
  *
  * The return value is the number of characters which have been written into
- * the @buf not including the trailing '\0'. If @size is <= 0 the function
+ * the @buf not including the trailing '\0'. If @size is == 0 the function
  * returns 0.
  *
  * Call this function if you are already dealing with a va_list.
@@ -958,7 +958,8 @@ EXPORT_SYMBOL(vsnprintf);
 int vscnprintf(char *buf, size_t size, const char *fmt, va_list args)
 {
        int i;
-
+       if (!size)
+               return 0;
        i=vsnprintf(buf,size,fmt,args);
        return (i >= size) ? (size - 1) : i;
 }
@@ -998,7 +999,7 @@ EXPORT_SYMBOL(snprintf);
  * @...: Arguments for the format string
  *
  * The return value is the number of characters written into @buf not including
- * the trailing '\0'. If @size is <= 0 the function returns 0.
+ * the trailing '\0'. If @size is == 0 the function returns 0.
  */
 
 int scnprintf(char * buf, size_t size, const char *fmt, ...)
@@ -1006,6 +1007,8 @@ int scnprintf(char * buf, size_t size, const char *fmt, ...)
        va_list args;
        int i;
 
+       if (!size)
+               return 0;
        va_start(args, fmt);
        i = vsnprintf(buf, size, fmt, args);
        va_end(args);

-- 
wbr, Vitaly
--
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