linux-kernel - [PATCH v2 05/21] kconfig: remove string expansion in file

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Date:   Tue, 27 Mar 2018 14:29:19 +0900
From:   Masahiro Yamada <yamada.masahiro@...ionext.com>
To:     linux-kbuild@...r.kernel.org
Cc:     Sam Ravnborg <sam@...nborg.org>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Arnd Bergmann <arnd@...db.de>,
        Ulf Magnusson <ulfalizer@...il.com>,
        Kees Cook <keescook@...omium.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Randy Dunlap <rdunlap@...radead.org>,
        "Luis R . Rodriguez" <mcgrof@...nel.org>,
        Nicolas Pitre <nico@...aro.org>,
        Masahiro Yamada <yamada.masahiro@...ionext.com>,
        linux-kernel@...r.kernel.org
Subject: [PATCH v2 05/21] kconfig: remove string expansion in file_lookup()

There are two callers of file_lookup().

[1] zconf_initscan()
    This is used to open the first Kconfig.  However, it cannot
    contain environments in the file path because zconf_fopen() is
    called before file_lookup().  By swapping the call order,
    KBUILD_KCONFIG would be able to contain environments, but I do
    not see practical benefits to support it.

[2] zconf_nextfile()
    This is used to open the next file from 'source' statement like
        source "arch/$SRCARCH/Kconfig"
    but this has already been expanded in the lexer phase.

So, file_lookup() does not need to expand the given path.

By the way, file_lookup() was already buggy; it expanded a given path,
but it used the path before expansion for look-up:
        if (!strcmp(name, file->name)) {

Signed-off-by: Masahiro Yamada <yamada.masahiro@...ionext.com>
---

Changes in v2:
  - Simplify the patch.  Just remove text expansion.

 scripts/kconfig/util.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/scripts/kconfig/util.c b/scripts/kconfig/util.c
index 136e497..3d27c49 100644
--- a/scripts/kconfig/util.c
+++ b/scripts/kconfig/util.c
@@ -58,18 +58,16 @@ char *expand_string_value(const char *in)
 struct file *file_lookup(const char *name)
 {
 	struct file *file;
-	char *file_name = expand_string_value(name);
 
 	for (file = file_list; file; file = file->next) {
 		if (!strcmp(name, file->name)) {
-			free(file_name);
 			return file;
 		}
 	}
 
 	file = xmalloc(sizeof(*file));
 	memset(file, 0, sizeof(*file));
-	file->name = file_name;
+	file->name = xstrdup(name);
 	file->next = file_list;
 	file_list = file;
 	return file;
-- 
2.7.4