From 30035e45753b708e7d47a98398500ca005e02b86 Mon Sep 17 00:00:00 2001 From: Chris Metcalf Date: Wed, 29 Apr 2015 12:52:04 -0400 Subject: string: provide strscpy() The strscpy() API is intended to be used instead of strlcpy(), and instead of most uses of strncpy(). - Unlike strlcpy(), it doesn't read from memory beyond (src + size). - Unlike strlcpy() or strncpy(), the API provides an easy way to check for destination buffer overflow: an -E2BIG error return value. - The provided implementation is robust in the face of the source buffer being asynchronously changed during the copy, unlike the current implementation of strlcpy(). - Unlike strncpy(), the destination buffer will be NUL-terminated if the string in the source buffer is too long. - Also unlike strncpy(), the destination buffer will not be updated beyond the NUL termination, avoiding strncpy's behavior of zeroing the entire tail end of the destination buffer. (A memset() after the strscpy() can be used if this behavior is desired.) - The implementation should be reasonably performant on all platforms since it uses the asm/word-at-a-time.h API rather than simple byte copy. Kernel-to-kernel string copy is not considered to be performance critical in any case. Signed-off-by: Chris Metcalf --- include/linux/string.h | 3 +++ 1 file changed, 3 insertions(+) (limited to 'include/linux/string.h') diff --git a/include/linux/string.h b/include/linux/string.h index a8d90db9c4b0..9ef7795e65e4 100644 --- a/include/linux/string.h +++ b/include/linux/string.h @@ -25,6 +25,9 @@ extern char * strncpy(char *,const char *, __kernel_size_t); #ifndef __HAVE_ARCH_STRLCPY size_t strlcpy(char *, const char *, size_t); #endif +#ifndef __HAVE_ARCH_STRSCPY +ssize_t __must_check strscpy(char *, const char *, size_t); +#endif #ifndef __HAVE_ARCH_STRCAT extern char * strcat(char *, const char *); #endif -- cgit v1.2.3