From 0d8024c6ebadb68f1154377c2e1996b4e649e4c8 Mon Sep 17 00:00:00 2001 From: "Yann E. MORIN" Date: Sat, 13 Apr 2013 22:49:13 +0200 Subject: kconfig: allow specifying the seed for randconfig 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 deletion(-) diff --git a/Documentation/kbuild/kconfig.txt b/Documentation/kbuild/kconfig.txt index b8b77bbc784f..dbf746b70553 100644 --- a/Documentation/kbuild/kconfig.txt +++ b/Documentation/kbuild/kconfig.txt @@ -89,6 +89,15 @@ These examples will disable most options (allnoconfig) but enable or 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' diff --git a/scripts/kconfig/conf.c b/scripts/kconfig/conf.c index e39fcd8143ea..bde5b95c8c19 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; } -- cgit