kconfig: KCONFIG_OVERWRITECONFIG

If you set KCONFIG_OVERWRITECONFIG in environment, Kconfig will not break
symlinks when .config is a symlink to somewhere else.

Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>

3 files changed, 33 insertions, 21 deletions

diff --git a/Makefile b/Makefile
index 3c55de99ed31..3cb9270c584d 100644
--- a/Makefile
+++ b/Makefile
@@ -178,6 +178,8 @@ CROSS_COMPILE	?=
 # Architecture as present in compile.h
 UTS_MACHINE := $(ARCH)
 
+KCONFIG_CONFIG  ?= .config
+
 # SHELL used by kbuild
 CONFIG_SHELL := $(shell if [ -x "$$BASH" ]; then echo $$BASH; \
           else if [ -x /bin/bash ]; then echo /bin/bash; \
@@ -437,13 +439,13 @@ ifeq ($(dot-config),1)
 -include include/config/auto.conf
 
 # To avoid any implicit rule to kick in, define an empty command
-.config include/config/auto.conf.cmd: ;
+$(KCONFIG_CONFIG) include/config/auto.conf.cmd: ;
 
 # If .config is newer than include/config/auto.conf, someone tinkered
 # with it and forgot to run make oldconfig.
 # if auto.conf.cmd is missing then we are probarly in a cleaned tree so
 # we execute the config step to be sure to catch updated Kconfig files
-include/config/auto.conf: .config include/config/auto.conf.cmd
+include/config/auto.conf: $(KCONFIG_CONFIG) include/config/auto.conf.cmd
         $(Q)$(MAKE) -f $(srctree)/Makefile silentoldconfig
 
 else
diff --git a/scripts/kconfig/confdata.c b/scripts/kconfig/confdata.c
index 5bd66f451189..2ee48c377b66 100644
--- a/scripts/kconfig/confdata.c
+++ b/scripts/kconfig/confdata.c
@@ -21,8 +21,6 @@ static void conf_warning(const char *fmt, ...)
 static const char *conf_filename;
 static int conf_lineno, conf_warnings, conf_unsaved;
 
-const char conf_def_filename[] = ".config";
-
 const char conf_defname[] = "arch/$ARCH/defconfig";
 
 static void conf_warning(const char *fmt, ...)
@@ -36,6 +34,13 @@ static void conf_warning(const char *fmt, ...)
         conf_warnings++;
 }
 
+const char *conf_get_configname(void)
+{
+        char *name = getenv("KCONFIG_CONFIG");
+
+        return name ? name : ".config";
+}
+
 static char *conf_expand_value(const char *in)
 {
         struct symbol *sym;
@@ -91,7 +96,7 @@ int conf_read_simple(const char *name, int def)
         } else {
                 struct property *prop;
 
-                name = conf_def_filename;
+                name = conf_get_configname();
                 in = zconf_fopen(name);
                 if (in)
                         goto load;
@@ -381,7 +386,7 @@ int conf_write(const char *name)
                 if (!stat(name, &st) && S_ISDIR(st.st_mode)) {
                         strcpy(dirname, name);
                         strcat(dirname, "/");
-                        basename = conf_def_filename;
+                        basename = conf_get_configname();
                 } else if ((slash = strrchr(name, '/'))) {
                         int size = slash - name + 1;
                         memcpy(dirname, name, size);
@@ -389,16 +394,24 @@ int conf_write(const char *name)
                         if (slash[1])
                                 basename = slash + 1;
                         else
-                                basename = conf_def_filename;
+                                basename = conf_get_configname();
                 } else
                         basename = name;
         } else
-                basename = conf_def_filename;
+                basename = conf_get_configname();
 
-        sprintf(newname, "%s.tmpconfig.%d", dirname, (int)getpid());
-        out = fopen(newname, "w");
+        sprintf(newname, "%s%s", dirname, basename);
+        env = getenv("KCONFIG_OVERWRITECONFIG");
+        if (!env || !*env) {
+                sprintf(tmpname, "%s.tmpconfig.%d", dirname, (int)getpid());
+                out = fopen(tmpname, "w");
+        } else {
+                *tmpname = 0;
+                out = fopen(newname, "w");
+        }
         if (!out)
                 return 1;
+
         sym = sym_lookup("KERNELVERSION", 0);
         sym_calc_value(sym);
         time(&now);
@@ -498,19 +511,18 @@ int conf_write(const char *name)
                 }
         }
         fclose(out);
-        if (!name || basename != conf_def_filename) {
-                if (!name)
-                        name = conf_def_filename;
-                sprintf(tmpname, "%s.old", name);
-                rename(name, tmpname);
+
+        if (*tmpname) {
+                strcat(dirname, name ? name : conf_get_configname());
+                strcat(dirname, ".old");
+                rename(newname, dirname);
+                if (rename(tmpname, newname))
+                        return 1;
         }
-        sprintf(tmpname, "%s%s", dirname, basename);
-        if (rename(newname, tmpname))
-                return 1;
 
         printf(_("#\n"
                  "# configuration written to %s\n"
-                 "#\n"), tmpname);
+                 "#\n"), newname);
 
         sym_change_count = 0;
 
diff --git a/scripts/kconfig/lkc.h b/scripts/kconfig/lkc.h
index 2d3d4ed3c9f2..2628023a1fe1 100644
--- a/scripts/kconfig/lkc.h
+++ b/scripts/kconfig/lkc.h
@@ -64,8 +64,6 @@ int zconf_lineno(void);
 char *zconf_curname(void);
 
 /* confdata.c */
-extern const char conf_def_filename[];
-
 char *conf_get_default_confname(void);
 
 /* kconfig_load.c */