diff options
| author | Yann E. MORIN <yann.morin.1998@free.fr> | 2013-04-13 22:49:13 +0200 |
|---|---|---|
| committer | Yann E. MORIN <yann.morin.1998@free.fr> | 2013-04-25 00:16:25 +0200 |
| commit | 0d8024c6ebadb68f1154377c2e1996b4e649e4c8 (patch) | |
| tree | bd38ec60a908adf8cf7c75aa7b3b19fab52d9e64 | |
| parent | 422c809f03f043d0950d8362214818e956a9daee (diff) | |
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" <yann.morin.1998@free.fr>
| -rw-r--r-- | Documentation/kbuild/kconfig.txt | 9 | ||||
| -rw-r--r-- | 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 b8b77bbc784f..dbf746b70553 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 e39fcd8143ea..bde5b95c8c19 100644 --- a/scripts/kconfig/conf.c +++ b/scripts/kconfig/conf.c @@ -13,6 +13,7 @@ #include <getopt.h> #include <sys/stat.h> #include <sys/time.h> +#include <errno.h> #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; } |