kconfig: warn of unhandled characters in Kconfig commands

In Kconfig, definitions of options take the following form:
"<COMMAND> <PARAM> <PARAM> ...". COMMANDs and PARAMs are treated
slightly different by the underlying parser.

While commit 2e0d737fc76f ("kconfig: don't silently ignore unhandled
characters") introduced a warning for unsupported characters around
PARAMs, it does not cover situations where a COMMAND has additional
characters before it.

This change makes Kconfig emit a warning if superfluous characters
are found before COMMANDs. As the 'help' statement sometimes is
written as '---help---', the '-' character would now also be regarded
as unhandled and generate a warning. To avoid that, '-' is added to
the list of allowed characters, and the token '---help---' is included
in the zconf.gperf file.

Reported-by: Valentin Rothberg <valentinrothberg@gmail.com>
Signed-off-by: Andreas Ruprecht <andreas.ruprecht@fau.de>
Reviewed-by: Ulf Magnusson <ulfalizer@gmail.com>
Tested-by: Ulf Magnusson <ulfalizer@gmail.com>
Signed-off-by: Michal Marek <mmarek@suse.com>

2 files changed, 12 insertions, 9 deletions

diff --git a/scripts/kconfig/zconf.gperf b/scripts/kconfig/zconf.gperf
index b6ac02d604f1..ac498f01b449 100644
--- a/scripts/kconfig/zconf.gperf
+++ b/scripts/kconfig/zconf.gperf
@@ -22,6 +22,7 @@ comment,	T_COMMENT,	TF_COMMAND
 config,         T_CONFIG,       TF_COMMAND
 menuconfig,     T_MENUCONFIG,   TF_COMMAND
 help,           T_HELP,         TF_COMMAND
+---help---,     T_HELP,         TF_COMMAND
 if,             T_IF,           TF_COMMAND|TF_PARAM
 endif,          T_ENDIF,        TF_COMMAND
 depends,        T_DEPENDS,      TF_COMMAND
diff --git a/scripts/kconfig/zconf.l b/scripts/kconfig/zconf.l
index 200a3fe30091..c410d257da06 100644
--- a/scripts/kconfig/zconf.l
+++ b/scripts/kconfig/zconf.l
@@ -66,9 +66,16 @@ static void alloc_string(const char *str, int size)
         memcpy(text, str, size);
         text[size] = 0;
 }
+
+static void warn_ignored_character(char chr)
+{
+        fprintf(stderr,
+                "%s:%d:warning: ignoring unsupported character '%c'\n",
+                zconf_curname(), zconf_lineno(), chr);
+}
 %}
 
-n       [A-Za-z0-9_]
+n       [A-Za-z0-9_-]
 
 %%
         int str = 0;
@@ -106,7 +113,7 @@ n	[A-Za-z0-9_]
                 zconflval.string = text;
                 return T_WORD;
         }
-        .
+        .       warn_ignored_character(*yytext);
         \n      {
                 BEGIN(INITIAL);
                 current_file->lineno++;
@@ -132,8 +139,7 @@ n	[A-Za-z0-9_]
                 BEGIN(STRING);
         }
         \n      BEGIN(INITIAL); current_file->lineno++; return T_EOL;
-        ---     /* ignore */
-        ({n}|[-/.])+    {
+        ({n}|[/.])+     {
                 const struct kconf_id *id = kconf_id_lookup(yytext, yyleng);
                 if (id && id->flags & TF_PARAM) {
                         zconflval.id = id;
@@ -146,11 +152,7 @@ n	[A-Za-z0-9_]
         #.*     /* comment */
         \\\n    current_file->lineno++;
         [[:blank:]]+
-        .       {
-                fprintf(stderr,
-                        "%s:%d:warning: ignoring unsupported character '%c'\n",
-                        zconf_curname(), zconf_lineno(), *yytext);
-        }
+        .       warn_ignored_character(*yytext);
         <<EOF>> {
                 BEGIN(INITIAL);
         }