linux-kernel - Re: [PATCH v2] Enable 'make CONFIG

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Date:	Fri, 29 Jul 2011 21:15:49 -0400
From:	Arnaud Lacombe <lacombar@...il.com>
To:	David Woodhouse <dwmw2@...radead.org>
Cc:	Michal Marek <mmarek@...e.cz>, "Ted Ts'o" <tytso@....edu>,
	Ingo Molnar <mingo@...e.hu>, x86@...nel.org,
	linux-kernel@...r.kernel.org, linux-kbuild@...r.kernel.org,
	hpa@...or.com
Subject: Re: [PATCH v2] Enable 'make CONFIG_FOO=y oldconfig'

Hi,

On Fri, Jul 29, 2011 at 7:32 PM, David Woodhouse <dwmw2@...radead.org> wrote:
> This allows you to set (and clear) config options on the make command
> line, for all config targets. For example:
>
>   make CONFIG_64BIT=n randconfig
>   make CONFIG_64BIT=n allmodconfig
>   make CONFIG_64BIT=y CONFIG_SATA_MV=y oldconfig
>
Technically, kconfig already provides you all the interfaces to set
symbol to a given value, for `randconfig' via "rand.config", for
`all{yes,mod,no}config', via all.{yes,mod,no}config, for oldconfig via
.config. Why another interface ?

> Signed-off-by: David Woodhouse <David.Woodhouse@...el.com>
> ---
> v2: Add call to sym_calc_value() before sym_set_string_value(), to set
>    symbol visibility. 'make ARCH=arm CONFIG_ARCH_OMAP=y allnoconfig'
>    should work correctly now.
>
>  scripts/kconfig/conf.c     |    7 ++++++-
>  scripts/kconfig/confdata.c |   42 ++++++++++++++++++++++++++++++++++++++++++
>  scripts/kconfig/lkc.h      |    1 +
>  3 files changed, 49 insertions(+), 1 deletions(-)
>
> diff --git a/scripts/kconfig/conf.c b/scripts/kconfig/conf.c
> index 006ad81..2b91e3b 100644
> --- a/scripts/kconfig/conf.c
> +++ b/scripts/kconfig/conf.c
> @@ -456,7 +456,7 @@ static struct option long_opts[] = {
>        {NULL, 0, NULL, 0}
>  };
>
> -int main(int ac, char **av)
> +int main(int ac, char **av, char **ep)
>  {
>        int opt;
>        const char *name;
> @@ -563,6 +563,11 @@ int main(int ac, char **av)
>                break;
>        }
>
> +       for ( ; *ep;  ep++) {
> +               if (!strncmp(*ep, CONFIG_, strlen(CONFIG_)))
> +                       conf_set_symbol_from_env(*ep);
> +       }
> +
>        if (sync_kconfig) {
>                if (conf_get_changed()) {
>                        name = getenv("KCONFIG_NOSILENTUPDATE");
> diff --git a/scripts/kconfig/confdata.c b/scripts/kconfig/confdata.c
> index 2bafd9a..ada3c4b 100644
> --- a/scripts/kconfig/confdata.c
> +++ b/scripts/kconfig/confdata.c
> @@ -338,6 +338,48 @@ setsym:
>        return 0;
>  }
>
> +void conf_set_symbol_from_env(char *str)
> +{
> +       char *p = strchr(str, '=');
> +       struct symbol *sym;
> +       int def = S_DEF_USER;
> +       int def_flags = SYMBOL_DEF << def;
> +
> +       if (!p)
> +               return;
the environment should already gives you the guarantee that `p' won't
be NULL. If that's not the case, the environment is likely to be
broken.

> +
> +       *p = 0;
> +       sym = sym_find(str + strlen(CONFIG_));
> +       *p++ = '=';
> +
> +       if (!sym)
> +               return;
> +
> +       sym_calc_value(sym);
> +       if (!sym_set_string_value(sym, p))
> +               return;
> +       conf_message("CONFIG_%s set to %s from environment", sym->name, p);
please do not hardcode the prefix.

> +       if (sym && sym_is_choice_value(sym)) {
you do not need to test for the validity of a pointer you
unconditionally dereference right before :)

> +               struct symbol *cs = prop_get_symbol(sym_get_choice_prop(sym));
> +               switch (sym->def[def].tri) {
> +               case no:
> +                       break;
> +               case mod:
> +                       if (cs->def[def].tri == yes) {
> +                               conf_warning("%s creates inconsistent choice state", sym->name);
> +                               cs->flags &= ~def_flags;
> +                       }
> +                       break;
> +               case yes:
> +                       if (cs->def[def].tri != no)
> +                               conf_warning("override: %s changes choice state", sym->name);
> +                       cs->def[def].val = sym;
> +                       break;
> +               }
> +               cs->def[def].tri = EXPR_OR(cs->def[def].tri, sym->def[def].tri);
> +       }
> +}
> +
>  int conf_read(const char *name)
>  {
>        struct symbol *sym, *choice_sym;
> diff --git a/scripts/kconfig/lkc.h b/scripts/kconfig/lkc.h
> index f34a0a9..fc2f3ad 100644
> --- a/scripts/kconfig/lkc.h
> +++ b/scripts/kconfig/lkc.h
> @@ -89,6 +89,7 @@ char *conf_get_default_confname(void);
>  void sym_set_change_count(int count);
>  void sym_add_change_count(int count);
>  void conf_set_all_new_symbols(enum conf_def_mode mode);
> +void conf_set_symbol_from_env(char *);
>
>  /* confdata.c and expr.c */
>  static inline void xfwrite(const void *str, size_t len, size_t count, FILE *out)
> --
> 1.7.6
>
>
> --
> dwmw2
>
>
--
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