From patchwork Wed Dec 28 23:34:57 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Michael Niedermayer X-Patchwork-Id: 1964 Delivered-To: ffmpegpatchwork@gmail.com Received: by 10.103.89.21 with SMTP id n21csp2176719vsb; Wed, 28 Dec 2016 15:35:10 -0800 (PST) X-Received: by 10.28.133.144 with SMTP id h138mr38962894wmd.12.1482968110160; Wed, 28 Dec 2016 15:35:10 -0800 (PST) Return-Path: Received: from ffbox0-bg.mplayerhq.hu (ffbox0-bg.ffmpeg.org. [79.124.17.100]) by mx.google.com with ESMTP id vt6si55681465wjb.55.2016.12.28.15.35.08; Wed, 28 Dec 2016 15:35:10 -0800 (PST) Received-SPF: pass (google.com: domain of ffmpeg-devel-bounces@ffmpeg.org designates 79.124.17.100 as permitted sender) client-ip=79.124.17.100; Authentication-Results: mx.google.com; spf=pass (google.com: domain of ffmpeg-devel-bounces@ffmpeg.org designates 79.124.17.100 as permitted sender) smtp.mailfrom=ffmpeg-devel-bounces@ffmpeg.org Received: from [127.0.1.1] (localhost [127.0.0.1]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTP id 40516689E48; Thu, 29 Dec 2016 01:35:03 +0200 (EET) X-Original-To: ffmpeg-devel@ffmpeg.org Delivered-To: ffmpeg-devel@ffmpeg.org Received: from vie01a-dmta-pe01-3.mx.upcmail.net (vie01a-dmta-pe01-3.mx.upcmail.net [62.179.121.156]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTPS id 35F7E689CF6 for ; Thu, 29 Dec 2016 01:34:56 +0200 (EET) Received: from [172.31.216.43] (helo=vie01a-pemc-psmtp-pe01) by vie01a-dmta-pe01.mx.upcmail.net with esmtp (Exim 4.87) (envelope-from ) id 1cMNkJ-0001db-7h for ffmpeg-devel@ffmpeg.org; Thu, 29 Dec 2016 00:34:59 +0100 Received: from localhost ([213.47.41.20]) by vie01a-pemc-psmtp-pe01 with SMTP @ mailcloud.upcmail.net id Rbay1u00C0S5wYM01baz6w; Thu, 29 Dec 2016 00:34:59 +0100 X-SourceIP: 213.47.41.20 From: Michael Niedermayer To: FFmpeg development discussions and patches Date: Thu, 29 Dec 2016 00:34:57 +0100 Message-Id: <20161228233457.12906-1-michael@niedermayer.cc> X-Mailer: git-send-email 2.11.0 Subject: [FFmpeg-devel] [PATCH] libavutil/random_seed: Ensure that get_generic_seed() spends at least 1/32 sec gathering entropy X-BeenThere: ffmpeg-devel@ffmpeg.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: FFmpeg development discussions and patches List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: FFmpeg development discussions and patches MIME-Version: 1.0 Errors-To: ffmpeg-devel-bounces@ffmpeg.org Sender: "ffmpeg-devel" This may fix the failures on windows Signed-off-by: Michael Niedermayer --- libavutil/random_seed.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/libavutil/random_seed.c b/libavutil/random_seed.c index 0c58c8ffa1..d1c9a3f704 100644 --- a/libavutil/random_seed.c +++ b/libavutil/random_seed.c @@ -68,6 +68,7 @@ static uint32_t get_generic_seed(void) struct AVSHA *sha = (void*)tmp; clock_t last_t = 0; clock_t last_td = 0; + clock_t init_t = 0; static uint64_t i = 0; static uint32_t buffer[512] = { 0 }; unsigned char digest[20]; @@ -93,10 +94,13 @@ static uint32_t get_generic_seed(void) } else { last_td = t - last_t; buffer[++i & 511] += last_td % 3294638521U; - if (last_i && i - last_i > 4 || i - last_i > 64 || TEST && i - last_i > 8) - break; + if ((t - init_t) >= CLOCKS_PER_SEC>>5) + if (last_i && i - last_i > 4 || i - last_i > 64 || TEST && i - last_i > 8) + break; } last_t = t; + if (!init_t) + init_t = t; } if(TEST) {