From 9af869c4145a668b6db9accdea554eb57895a25e Mon Sep 17 00:00:00 2001 From: Sean Anderson Date: Thu, 11 Mar 2021 00:15:42 -0500 Subject: lib: string: Implement strlcat This introduces strlcat, which provides a safer interface than strncat. It never copies more than its size bytes, including the terminating nul. In addition, it never reads past dest[size - 1], even if dest is not nul-terminated. This also removes the stub for dwc3 now that we have a proper implementation. Signed-off-by: Sean Anderson Reviewed-by: Simon Glass --- lib/string.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) (limited to 'lib') diff --git a/lib/string.c b/lib/string.c index 1b867ac09d..a0cff8fe88 100644 --- a/lib/string.c +++ b/lib/string.c @@ -180,6 +180,25 @@ char * strncat(char *dest, const char *src, size_t count) } #endif +#ifndef __HAVE_ARCH_STRLCAT +/** + * strlcat - Append a length-limited, %NUL-terminated string to another + * @dest: The string to be appended to + * @src: The string to append to it + * @size: The size of @dest + * + * Compatible with *BSD: the result is always a valid NUL-terminated string that + * fits in the buffer (unless, of course, the buffer size is zero). It does not + * write past @size like strncat() does. + */ +size_t strlcat(char *dest, const char *src, size_t size) +{ + size_t len = strnlen(dest, size); + + return len + strlcpy(dest + len, src, size - len); +} +#endif + #ifndef __HAVE_ARCH_STRCMP /** * strcmp - Compare two strings -- cgit v1.2.3