When "str >= end", necessary to reset 'str' to "end - 1", or the return value will be larger than the real one, the callers which depend on the return value, may cause memory overflow.
When for copying constant string, 'str' is point to destination buffer, so it need add 'copy' (for destination buffer), not 'read' (for source buffer). Also add white space between variable and operator to make code cleaner. Signed-off-by: Chen Gang <gang.c...@asianux.com> --- lib/vsprintf.c | 8 +++++--- 1 files changed, 5 insertions(+), 3 deletions(-) diff --git a/lib/vsprintf.c b/lib/vsprintf.c index 739a363..b153768 100644 --- a/lib/vsprintf.c +++ b/lib/vsprintf.c @@ -1542,7 +1542,7 @@ int vsnprintf(char *buf, size_t size, const char *fmt, va_list args) copy = end - str; memcpy(str, old_fmt, copy); } - str += read; + str += copy; break; } @@ -1662,12 +1662,14 @@ int vsnprintf(char *buf, size_t size, const char *fmt, va_list args) if (size > 0) { if (str < end) *str = '\0'; - else + else { end[-1] = '\0'; + str = end - 1; + } } /* the trailing null byte doesn't count towards the total */ - return str-buf; + return str - buf; } EXPORT_SYMBOL(vsnprintf); -- 1.7.7.6 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/