From f6835b82a8dbb3a9688c7b28fd4d673dca371272 Mon Sep 17 00:00:00 2001 From: Mathieu Desnoyers Date: Mon, 16 May 2016 21:42:40 -0400 Subject: [PATCH] Implement lttng_strncpy safe string copy MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Signed-off-by: Mathieu Desnoyers Signed-off-by: Jérémie Galarneau --- src/common/macros.h | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) diff --git a/src/common/macros.h b/src/common/macros.h index 308d3d57a..930438855 100644 --- a/src/common/macros.h +++ b/src/common/macros.h @@ -20,6 +20,7 @@ #define _MACROS_H #include +#include /* * Takes a pointer x and transform it so we can use it to access members @@ -76,4 +77,28 @@ void *zmalloc(size_t len) #define LTTNG_HIDDEN __attribute__((visibility("hidden"))) #endif +/* + * lttng_strncpy returns 0 on success, or nonzero on failure. + * It checks that the @src string fits into @dst_len before performing + * the copy. On failure, no copy has been performed. + * + * dst_len includes the string's trailing NULL. + */ +static inline +int lttng_strncpy(char *dst, const char *src, size_t dst_len) +{ + if (strnlen(src, dst_len) == dst_len) { + /* Fail since copying would result in truncation. */ + return -1; + } + strncpy(dst, src, dst_len); + /* + * Be extra careful and put final \0 at the end after strncpy(), + * even though we checked the length before. This makes Coverity + * happy. + */ + dst[dst_len - 1] = '\0'; + return 0; +} + #endif /* _MACROS_H */ -- 2.34.1