linux-kernel - Re: [PATCH v2 2/3] kconfig: Ask user if string needs to be changed when dependency changed

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Message-ID: <CAK7LNAS54Zw7d8Lp5BNs1JVktSLTFx0dNbLMA7W0U_sH2712_A@mail.gmail.com>
Date:   Sun, 21 Feb 2021 17:47:12 +0900
From:   Masahiro Yamada <masahiroy@...nel.org>
To:     Mickaël Salaün <mic@...ikod.net>
Cc:     James Morris <jmorris@...ei.org>,
        "Serge E . Hallyn" <serge@...lyn.com>,
        Casey Schaufler <casey@...aufler-ca.com>,
        Nicolas Iooss <nicolas.iooss@....org>,
        Linux Kbuild mailing list <linux-kbuild@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        linux-security-module <linux-security-module@...r.kernel.org>,
        Mickaël Salaün <mic@...ux.microsoft.com>
Subject: Re: [PATCH v2 2/3] kconfig: Ask user if string needs to be changed
 when dependency changed

On Tue, Feb 16, 2021 at 3:14 AM Mickaël Salaün <mic@...ikod.net> wrote:
>
> From: Mickaël Salaün <mic@...ux.microsoft.com>
>
> Content of string configuration may depend on related kernel
> configurations.  Modify oldconfig and syncconfig to inform users about
> possible required configuration update and give them the opportunity to
> update it:
> * if dependencies of this string has changed (e.g. enabled or disabled),
> * and if the current value of this string is different than the (new)
>   default one.
>
> This is particularly relevant for CONFIG_LSM which contains a list of
> LSMs enabled at boot, but users will not have a chance to update this
> list with a make oldconfig.

If CONFIG_LSM already exists in the .config,
oldconfig does not show a prompt.
This is the expected behavior.

You are trying to fix your problem in a wrong way.
NACK.



>
> Cc: Casey Schaufler <casey@...aufler-ca.com>
> Cc: James Morris <jmorris@...ei.org>
> Cc: Masahiro Yamada <masahiroy@...nel.org>
> Cc: Serge E. Hallyn <serge@...lyn.com>
> Signed-off-by: Mickaël Salaün <mic@...ux.microsoft.com>
> Link: https://lore.kernel.org/r/20210215181511.2840674-3-mic@digikod.net
> ---
>  scripts/kconfig/conf.c | 37 ++++++++++++++++++++++++++++++++++---
>  1 file changed, 34 insertions(+), 3 deletions(-)
>
> diff --git a/scripts/kconfig/conf.c b/scripts/kconfig/conf.c
> index 18a233d27a8d..8633dacd39a9 100644
> --- a/scripts/kconfig/conf.c
> +++ b/scripts/kconfig/conf.c
> @@ -82,6 +82,26 @@ static void xfgets(char *str, int size, FILE *in)
>                 printf("%s", str);
>  }
>
> +static bool may_need_string_update(struct symbol *sym, const char *def)
> +{
> +       const struct symbol *dep_sym;
> +       const struct expr *e;
> +
> +       if (sym->type != S_STRING)
> +               return false;
> +       if (strcmp(def, sym_get_string_default(sym)) == 0)
> +               return false;
> +       /*
> +        * The user may want to synchronize the content of a string related to
> +        * changed dependencies (e.g. CONFIG_LSM).
> +        */
> +       expr_list_for_each_sym(sym->dir_dep.expr, e, dep_sym) {
> +               if (dep_sym->flags & SYMBOL_CHANGED)
> +                       return true;
> +       }
> +       return false;
> +}
> +
>  static int conf_askvalue(struct symbol *sym, const char *def)
>  {
>         enum symbol_type type = sym_get_type(sym);
> @@ -102,7 +122,7 @@ static int conf_askvalue(struct symbol *sym, const char *def)
>         switch (input_mode) {
>         case oldconfig:
>         case syncconfig:
> -               if (sym_has_value(sym)) {
> +               if (sym_has_value(sym) && !may_need_string_update(sym, def)) {
>                         printf("%s\n", def);
>                         return 0;
>                 }
> @@ -137,8 +157,19 @@ static int conf_string(struct menu *menu)
>                 printf("%*s%s ", indent - 1, "", menu->prompt->text);
>                 printf("(%s) ", sym->name);
>                 def = sym_get_string_value(sym);
> -               if (def)
> -                       printf("[%s] ", def);
> +               if (def) {
> +                       if (may_need_string_update(sym, def)) {
> +                               indent += 2;
> +                               printf("\n%*sDefault value is [%s]\n",
> +                                               indent - 1, "",
> +                                               sym_get_string_default(sym));
> +                               printf("%*sCurrent value is [%s] ",
> +                                               indent - 1, "", def);
> +                               indent -= 2;
> +                       } else {
> +                               printf("[%s] ", def);
> +                       }
> +               }
>                 if (!conf_askvalue(sym, def))
>                         return 0;
>                 switch (line[0]) {
> --
> 2.30.0
>


-- 
Best Regards
Masahiro Yamada