From 75f32f047cc380bdb648faf3ee277f7dc3cdd007 Mon Sep 17 00:00:00 2001 From: Zbigniew Jędrzejewski-Szmek Date: Mon, 1 Feb 2016 21:57:41 -0500 Subject: Add memcpy_safe MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit ISO/IEC 9899:1999 §7.21.1/2 says: Where an argument declared as size_t n specifies the length of the array for a function, n can have the value zero on a call to that function. Unless explicitly stated otherwise in the description of a particular function in this subclause, pointer arguments on such a call shall still have valid values, as described in 7.1.4. In base64_append_width memcpy was called as memcpy(x, NULL, 0). GCC 4.9 started making use of this and assumes This worked fine under -O0, but does something strange under -O3. This patch fixes a bug in base64_append_width(), fixes a possible bug in journal_file_append_entry_internal(), and makes use of the new function to simplify the code in other places. --- src/basic/util.h | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'src/basic/util.h') diff --git a/src/basic/util.h b/src/basic/util.h index 76a06822b7..b7bad76212 100644 --- a/src/basic/util.h +++ b/src/basic/util.h @@ -104,6 +104,16 @@ static inline void qsort_safe(void *base, size_t nmemb, size_t size, comparison_ qsort(base, nmemb, size, compar); } +/** + * Normal memcpy requires src to be nonnull. We do nothing if n is 0. + */ +static inline void memcpy_safe(void *dst, const void *src, size_t n) { + if (n == 0) + return; + assert(src); + memcpy(dst, src, n); +} + int on_ac_power(void); #define memzero(x,l) (memset((x), 0, (l))) -- cgit v1.2.3-54-g00ecf