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

On 21/02/2021 09:47, Masahiro Yamada wrote:

On Tue, Feb 16, 2021 at 3:14 AM Mickaël Salaün [off-list ref] wrote:

quoted

From: Mickaël Salaün <redacted>

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.

It is not the behavior wished for LSM stacking.

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

What do you suggest to ensure that users will be asked to update the
CONFIG_LSM string if they add or remove an LSM?

quoted

Cc: Casey Schaufler <casey@schaufler-ca.com>
Cc: James Morris <jmorris@namei.org>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Serge E. Hallyn <serge@hallyn.com>
Signed-off-by: Mickaël Salaün <redacted>
Link: https://lore.kernel.org/r/20210215181511.2840674-3-mic@digikod.net (local)
---
 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