From 39f8c7961dcd530e88d13c600145097106647d2e Mon Sep 17 00:00:00 2001 From: Ganesh Ajjanagadde Date: Sun, 6 Dec 2015 21:10:21 -0500 Subject: [PATCH] lavu/random_seed: use arc4random() when available arc4random() was designed as a superior interface for system random number generation, designed for OpenBSD and subsequently incorporated by other BSD's, Mac OS X, and some non-standard libc's. It is thus an improvement to use it whenever available. As a side note, this may or may not get included in glibc, and there is a proposal to create a posix_random family based on these ideas: http://austingroupbugs.net/view.php?id=859. Tested on Mac OS X. Signed-off-by: Ganesh Ajjanagadde --- configure | 2 ++ libavutil/random_seed.c | 4 ++++ 2 files changed, 6 insertions(+) diff --git a/configure b/configure index 7662f37133..dc1d2eb807 100755 --- a/configure +++ b/configure @@ -1841,6 +1841,7 @@ MATH_FUNCS=" SYSTEM_FUNCS=" access aligned_malloc + arc4random clock_gettime closesocket CommandLineToArgvW @@ -5232,6 +5233,7 @@ check_func ${malloc_prefix}memalign && enable memalign check_func ${malloc_prefix}posix_memalign && enable posix_memalign check_func access +check_func arc4random check_func_headers time.h clock_gettime || { check_func_headers time.h clock_gettime -lrt && add_extralibs -lrt && LIBRT="-lrt"; } check_func fcntl check_func fork diff --git a/libavutil/random_seed.c b/libavutil/random_seed.c index 8aa8c3879b..205a636f92 100644 --- a/libavutil/random_seed.c +++ b/libavutil/random_seed.c @@ -121,6 +121,10 @@ uint32_t av_get_random_seed(void) } #endif +#if HAVE_ARC4RANDOM + return arc4random(); +#endif + if (read_random(&seed, "/dev/urandom") == sizeof(seed)) return seed; if (read_random(&seed, "/dev/random") == sizeof(seed))