Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965180Ab3DPRoJ (ORCPT ); Tue, 16 Apr 2013 13:44:09 -0400 Received: from mail-wi0-f179.google.com ([209.85.212.179]:45596 "EHLO mail-wi0-f179.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965099Ab3DPRna (ORCPT ); Tue, 16 Apr 2013 13:43:30 -0400 From: "Yann E. MORIN" To: linux-kbuild@vger.kernel.org Cc: Michal Marek , linux-kernel@vger.kernel.org, "Yann E. MORIN" Subject: [PATCH 2/4] kconfig: allow specifying the seed for randconfig Date: Tue, 16 Apr 2013 19:43:11 +0200 Message-Id: <1366134193-22030-3-git-send-email-yann.morin.1998@free.fr> X-Mailer: git-send-email 1.7.2.5 In-Reply-To: <1366134193-22030-1-git-send-email-yann.morin.1998@free.fr> References: <1366134193-22030-1-git-send-email-yann.morin.1998@free.fr> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2570 Lines: 85 For reproducibility, it can be useful to be able to specify the seed to use to seed the RNG. Add a new KCONFIG_SEED environment variable which can be set to the seed to use: $ make KCONFIG_SEED=42 randconfig $ sha1sum .config 70a128c8dcc61303069e1be352cce64114dfcbca .config $ make KCONFIG_SEED=42 randconfig $ sha1sum .config 70a128c8dcc61303069e1be352cce64114dfcbca .config It's very usefull for eg. debugging the kconfig parser. Signed-off-by: "Yann E. MORIN" --- Documentation/kbuild/kconfig.txt | 9 +++++++++ scripts/kconfig/conf.c | 12 +++++++++++- 2 files changed, 20 insertions(+), 1 deletions(-) diff --git a/Documentation/kbuild/kconfig.txt b/Documentation/kbuild/kconfig.txt index b8b77bb..dbf746b 100644 --- a/Documentation/kbuild/kconfig.txt +++ b/Documentation/kbuild/kconfig.txt @@ -90,6 +90,15 @@ disable the options that are explicitly listed in the specified mini-config files. ______________________________________________________________________ +Environment variables for 'randconfig' + +KCONFIG_SEED +-------------------------------------------------- +You can set this to the integer value used to seed the RNG, if you want +to somehow debug the behaviour of the kconfig parser/frontends. +If not set, the current time will be used. + +______________________________________________________________________ Environment variables for 'silentoldconfig' KCONFIG_NOSILENTUPDATE diff --git a/scripts/kconfig/conf.c b/scripts/kconfig/conf.c index e39fcd8..bde5b95 100644 --- a/scripts/kconfig/conf.c +++ b/scripts/kconfig/conf.c @@ -13,6 +13,7 @@ #include #include #include +#include #include "lkc.h" @@ -514,14 +515,23 @@ int main(int ac, char **av) { struct timeval now; unsigned int seed; + char *seed_env; /* * Use microseconds derived seed, * compensate for systems where it may be zero */ gettimeofday(&now, NULL); - seed = (unsigned int)((now.tv_sec + 1) * (now.tv_usec + 1)); + + seed_env = getenv("KCONFIG_SEED"); + if( seed_env && *seed_env ) { + char *endp; + int tmp = (int)strtol(seed_env, &endp, 10); + if (*endp == '\0') { + seed = tmp; + } + } srand(seed); break; } -- 1.7.2.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/