[PATCH v1 2/3] kconfig: Ask user if string needs to be changed when dependency changed

From: Mickaël Salaün
Date: Mon Feb 15 2021 - 07:30:52 EST


From: Mickaël Salaün <mic@xxxxxxxxxxxxxxxxxxx>

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.

Cc: Casey Schaufler <casey@xxxxxxxxxxxxxxxx>
Cc: James Morris <jmorris@xxxxxxxxx>
Cc: Masahiro Yamada <masahiroy@xxxxxxxxxx>
Cc: Serge E. Hallyn <serge@xxxxxxxxxx>
Signed-off-by: Mickaël Salaün <mic@xxxxxxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20210215122513.1773897-3-mic@xxxxxxxxxxx
---
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