kconfig: fix .config dependencies

This fixes one of the worst kbuild warts left - the broken dependencies used
to check and regenerate the .config file.  This was done via an indirect
dependency and the .config itself had an empty command, which can cause make
not to reread the changed .config file.

Instead of this we generate now a new file include/config/auto.conf from
.config, which is used for kbuild and has the proper dependencies.  It's also
the main make target now for all files generated during this step (and thus
replaces include/linux/autoconf.h).

This also means we can now relax the syntax requirements for the .config file
and we don't have to rewrite it all the time, i.e.  silentoldconfig only
writes .config now when it's necessary to keep it in sync with the Kconfig
files and even this can be suppressed by setting the environment variable
KCONFIG_NOSILENTUPDATE, so the update can (and must) be done manually.

Signed-off-by: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>

1 files changed, 124 insertions, 53 deletions

diff --git a/scripts/kconfig/confdata.c b/scripts/kconfig/confdata.c
index a9e3b6abf661..2da4a8d775a5 100644
--- a/scripts/kconfig/confdata.c
+++ b/scripts/kconfig/confdata.c
@@ -342,7 +342,7 @@ int conf_read(const char *name)
 
 int conf_write(const char *name)
 {
-	FILE *out, *out_h;
+	FILE *out;
 	struct symbol *sym;
 	struct menu *menu;
 	const char *basename;
@@ -379,13 +379,6 @@ int conf_write(const char *name)
 	out = fopen(newname, "w");
 	if (!out)
 		return 1;
-	out_h = NULL;
-	if (!name) {
-		out_h = fopen(".tmpconfig.h", "w");
-		if (!out_h)
-			return 1;
-		file_write_dep(NULL);
-	}
 	sym = sym_lookup("KERNELVERSION", 0);
 	sym_calc_value(sym);
 	time(&now);
@@ -401,16 +394,6 @@ int conf_write(const char *name)
 		     sym_get_string_value(sym),
 		     use_timestamp ? "# " : "",
 		     use_timestamp ? ctime(&now) : "");
-	if (out_h)
-		fprintf(out_h, "/*\n"
-			       " * Automatically generated C config: don't edit\n"
-			       " * Linux kernel version: %s\n"
-			       "%s%s"
-			       " */\n"
-			       "#define AUTOCONF_INCLUDED\n",
-			       sym_get_string_value(sym),
-			       use_timestamp ? " * " : "",
-			       use_timestamp ? ctime(&now) : "");
 
 	if (!sym_change_count)
 		sym_clear_all_valid();
@@ -426,11 +409,6 @@ int conf_write(const char *name)
 				     "#\n"
 				     "# %s\n"
 				     "#\n", str);
-			if (out_h)
-				fprintf(out_h, "\n"
-					       "/*\n"
-					       " * %s\n"
-					       " */\n", str);
 		} else if (!(sym->flags & SYMBOL_CHOICE)) {
 			sym_calc_value(sym);
 			if (!(sym->flags & SYMBOL_WRITE))
@@ -448,59 +426,39 @@ int conf_write(const char *name)
 				switch (sym_get_tristate_value(sym)) {
 				case no:
 					fprintf(out, "# CONFIG_%s is not set\n", sym->name);
-					if (out_h)
-						fprintf(out_h, "#undef CONFIG_%s\n", sym->name);
 					break;
 				case mod:
 					fprintf(out, "CONFIG_%s=m\n", sym->name);
-					if (out_h)
-						fprintf(out_h, "#define CONFIG_%s_MODULE 1\n", sym->name);
 					break;
 				case yes:
 					fprintf(out, "CONFIG_%s=y\n", sym->name);
-					if (out_h)
-						fprintf(out_h, "#define CONFIG_%s 1\n", sym->name);
 					break;
 				}
 				break;
 			case S_STRING:
-				// fix me
 				str = sym_get_string_value(sym);
 				fprintf(out, "CONFIG_%s=\"", sym->name);
-				if (out_h)
-					fprintf(out_h, "#define CONFIG_%s \"", sym->name);
-				do {
+				while (1) {
 					l = strcspn(str, "\"\\");
 					if (l) {
 						fwrite(str, l, 1, out);
-						if (out_h)
-							fwrite(str, l, 1, out_h);
-					}
-					str += l;
-					while (*str == '\\' || *str == '"') {
-						fprintf(out, "\\%c", *str);
-						if (out_h)
-							fprintf(out_h, "\\%c", *str);
-						str++;
+						str += l;
 					}
-				} while (*str);
+					if (!*str)
+						break;
+					fprintf(out, "\\%c", *str++);
+				}
 				fputs("\"\n", out);
-				if (out_h)
-					fputs("\"\n", out_h);
 				break;
 			case S_HEX:
 				str = sym_get_string_value(sym);
 				if (str[0] != '0' || (str[1] != 'x' && str[1] != 'X')) {
 					fprintf(out, "CONFIG_%s=%s\n", sym->name, str);
-					if (out_h)
-						fprintf(out_h, "#define CONFIG_%s 0x%s\n", sym->name, str);
 					break;
 				}
 			case S_INT:
 				str = sym_get_string_value(sym);
 				fprintf(out, "CONFIG_%s=%s\n", sym->name, str);
-				if (out_h)
-					fprintf(out_h, "#define CONFIG_%s %s\n", sym->name, str);
 				break;
 			}
 		}
@@ -520,10 +478,6 @@ int conf_write(const char *name)
 		}
 	}
 	fclose(out);
-	if (out_h) {
-		fclose(out_h);
-		rename(".tmpconfig.h", "include/linux/autoconf.h");
-	}
 	if (!name || basename != conf_def_filename) {
 		if (!name)
 			name = conf_def_filename;
@@ -542,3 +496,120 @@ int conf_write(const char *name)
 
 	return 0;
 }
+
+int conf_write_autoconf(void)
+{
+	struct symbol *sym;
+	const char *str;
+	char *name;
+	FILE *out, *out_h;
+	time_t now;
+	int i, l;
+
+	file_write_dep("include/config/auto.conf.cmd");
+
+	out = fopen(".tmpconfig", "w");
+	if (!out)
+		return 1;
+
+	out_h = fopen(".tmpconfig.h", "w");
+	if (!out_h) {
+		fclose(out);
+		return 1;
+	}
+
+	sym = sym_lookup("KERNELVERSION", 0);
+	sym_calc_value(sym);
+	time(&now);
+	fprintf(out, "#\n"
+		     "# Automatically generated make config: don't edit\n"
+		     "# Linux kernel version: %s\n"
+		     "# %s"
+		     "#\n",
+		     sym_get_string_value(sym), ctime(&now));
+	fprintf(out_h, "/*\n"
+		       " * Automatically generated C config: don't edit\n"
+		       " * Linux kernel version: %s\n"
+		       " * %s"
+		       " */\n"
+		       "#define AUTOCONF_INCLUDED\n",
+		       sym_get_string_value(sym), ctime(&now));
+
+	sym_clear_all_valid();
+
+	for_all_symbols(i, sym) {
+		sym_calc_value(sym);
+		if (!(sym->flags & SYMBOL_WRITE) || !sym->name)
+			continue;
+		switch (sym->type) {
+		case S_BOOLEAN:
+		case S_TRISTATE:
+			switch (sym_get_tristate_value(sym)) {
+			case no:
+				break;
+			case mod:
+				fprintf(out, "CONFIG_%s=m\n", sym->name);
+				fprintf(out_h, "#define CONFIG_%s_MODULE 1\n", sym->name);
+				break;
+			case yes:
+				fprintf(out, "CONFIG_%s=y\n", sym->name);
+				fprintf(out_h, "#define CONFIG_%s 1\n", sym->name);
+				break;
+			}
+			break;
+		case S_STRING:
+			str = sym_get_string_value(sym);
+			fprintf(out, "CONFIG_%s=\"", sym->name);
+			fprintf(out_h, "#define CONFIG_%s \"", sym->name);
+			while (1) {
+				l = strcspn(str, "\"\\");
+				if (l) {
+					fwrite(str, l, 1, out);
+					fwrite(str, l, 1, out_h);
+					str += l;
+				}
+				if (!*str)
+					break;
+				fprintf(out, "\\%c", *str);
+				fprintf(out_h, "\\%c", *str);
+				str++;
+			}
+			fputs("\"\n", out);
+			fputs("\"\n", out_h);
+			break;
+		case S_HEX:
+			str = sym_get_string_value(sym);
+			if (str[0] != '0' || (str[1] != 'x' && str[1] != 'X')) {
+				fprintf(out, "CONFIG_%s=%s\n", sym->name, str);
+				fprintf(out_h, "#define CONFIG_%s 0x%s\n", sym->name, str);
+				break;
+			}
+		case S_INT:
+			str = sym_get_string_value(sym);
+			fprintf(out, "CONFIG_%s=%s\n", sym->name, str);
+			fprintf(out_h, "#define CONFIG_%s %s\n", sym->name, str);
+			break;
+		default:
+			break;
+		}
+	}
+	fclose(out);
+	fclose(out_h);
+
+	name = getenv("KCONFIG_AUTOHEADER");
+	if (!name)
+		name = "include/linux/autoconf.h";
+	if (rename(".tmpconfig.h", name))
+		return 1;
+	name = getenv("KCONFIG_AUTOCONFIG");
+	if (!name)
+		name = "include/config/auto.conf";
+	/*
+	 * This must be the last step, kbuild has a dependency on auto.conf
+	 * and this marks the successful completion of the previous steps.
+	 */
+	if (rename(".tmpconfig", name))
+		return 1;
+
+	return 0;
+}