Import kconfig from the linux kernel

- commit: 0988a0ea791999ebbf95693f2676381825b05033
- path: scripts/kconfig

1 files changed, 1263 insertions, 0 deletions

diff --git a/tools/kconfig/confdata.c b/tools/kconfig/confdata.c
new file mode 100644
index 0000000..b7c9f1d
--- /dev/null
+++ b/tools/kconfig/confdata.c
@@ -0,0 +1,1263 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2002 Roman Zippel <zippel@linux-m68k.org>
+ */
+
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <ctype.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <limits.h>
+#include <stdarg.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+#include <unistd.h>
+
+#include "lkc.h"
+
+/* return true if 'path' exists, false otherwise */
+static bool is_present(const char *path)
+{
+	struct stat st;
+
+	return !stat(path, &st);
+}
+
+/* return true if 'path' exists and it is a directory, false otherwise */
+static bool is_dir(const char *path)
+{
+	struct stat st;
+
+	if (stat(path, &st))
+		return false;
+
+	return S_ISDIR(st.st_mode);
+}
+
+/* return true if the given two files are the same, false otherwise */
+static bool is_same(const char *file1, const char *file2)
+{
+	int fd1, fd2;
+	struct stat st1, st2;
+	void *map1, *map2;
+	bool ret = false;
+
+	fd1 = open(file1, O_RDONLY);
+	if (fd1 < 0)
+		return ret;
+
+	fd2 = open(file2, O_RDONLY);
+	if (fd2 < 0)
+		goto close1;
+
+	ret = fstat(fd1, &st1);
+	if (ret)
+		goto close2;
+	ret = fstat(fd2, &st2);
+	if (ret)
+		goto close2;
+
+	if (st1.st_size != st2.st_size)
+		goto close2;
+
+	map1 = mmap(NULL, st1.st_size, PROT_READ, MAP_PRIVATE, fd1, 0);
+	if (map1 == MAP_FAILED)
+		goto close2;
+
+	map2 = mmap(NULL, st2.st_size, PROT_READ, MAP_PRIVATE, fd2, 0);
+	if (map2 == MAP_FAILED)
+		goto close2;
+
+	if (bcmp(map1, map2, st1.st_size))
+		goto close2;
+
+	ret = true;
+close2:
+	close(fd2);
+close1:
+	close(fd1);
+
+	return ret;
+}
+
+/*
+ * Create the parent directory of the given path.
+ *
+ * For example, if 'include/config/auto.conf' is given, create 'include/config'.
+ */
+static int make_parent_dir(const char *path)
+{
+	char tmp[PATH_MAX + 1];
+	char *p;
+
+	strncpy(tmp, path, sizeof(tmp));
+	tmp[sizeof(tmp) - 1] = 0;
+
+	/* Remove the base name. Just return if nothing is left */
+	p = strrchr(tmp, '/');
+	if (!p)
+		return 0;
+	*(p + 1) = 0;
+
+	/* Just in case it is an absolute path */
+	p = tmp;
+	while (*p == '/')
+		p++;
+
+	while ((p = strchr(p, '/'))) {
+		*p = 0;
+
+		/* skip if the directory exists */
+		if (!is_dir(tmp) && mkdir(tmp, 0755))
+			return -1;
+
+		*p = '/';
+		while (*p == '/')
+			p++;
+	}
+
+	return 0;
+}
+
+static char depfile_path[PATH_MAX];
+static size_t depfile_prefix_len;
+
+/* touch depfile for symbol 'name' */
+static int conf_touch_dep(const char *name)
+{
+	int fd;
+
+	/* check overflow: prefix + name + '\0' must fit in buffer. */
+	if (depfile_prefix_len + strlen(name) + 1 > sizeof(depfile_path))
+		return -1;
+
+	strcpy(depfile_path + depfile_prefix_len, name);
+
+	fd = open(depfile_path, O_WRONLY | O_CREAT | O_TRUNC, 0644);
+	if (fd == -1)
+		return -1;
+	close(fd);
+
+	return 0;
+}
+
+static void conf_warning(const char *fmt, ...)
+	__attribute__ ((format (printf, 1, 2)));
+
+static void conf_message(const char *fmt, ...)
+	__attribute__ ((format (printf, 1, 2)));
+
+static const char *conf_filename;
+static int conf_lineno, conf_warnings;
+
+static void conf_warning(const char *fmt, ...)
+{
+	va_list ap;
+	va_start(ap, fmt);
+	fprintf(stderr, "%s:%d:warning: ", conf_filename, conf_lineno);
+	vfprintf(stderr, fmt, ap);
+	fprintf(stderr, "\n");
+	va_end(ap);
+	conf_warnings++;
+}
+
+static void conf_default_message_callback(const char *s)
+{
+	printf("#\n# ");
+	printf("%s", s);
+	printf("\n#\n");
+}
+
+static void (*conf_message_callback)(const char *s) =
+	conf_default_message_callback;
+void conf_set_message_callback(void (*fn)(const char *s))
+{
+	conf_message_callback = fn;
+}
+
+static void conf_message(const char *fmt, ...)
+{
+	va_list ap;
+	char buf[4096];
+
+	if (!conf_message_callback)
+		return;
+
+	va_start(ap, fmt);
+
+	vsnprintf(buf, sizeof(buf), fmt, ap);
+	conf_message_callback(buf);
+	va_end(ap);
+}
+
+const char *conf_get_configname(void)
+{
+	char *name = getenv("KCONFIG_CONFIG");
+
+	return name ? name : ".config";
+}
+
+static const char *conf_get_autoconfig_name(void)
+{
+	char *name = getenv("KCONFIG_AUTOCONFIG");
+
+	return name ? name : "include/config/auto.conf";
+}
+
+static const char *conf_get_autoheader_name(void)
+{
+	char *name = getenv("KCONFIG_AUTOHEADER");
+
+	return name ? name : "include/generated/autoconf.h";
+}
+
+static const char *conf_get_rustccfg_name(void)
+{
+	char *name = getenv("KCONFIG_RUSTCCFG");
+
+	return name ? name : "include/generated/rustc_cfg";
+}
+
+static int conf_set_sym_val(struct symbol *sym, int def, int def_flags, char *p)
+{
+	char *p2;
+
+	switch (sym->type) {
+	case S_TRISTATE:
+		if (p[0] == 'm') {
+			sym->def[def].tri = mod;
+			sym->flags |= def_flags;
+			break;
+		}
+		/* fall through */
+	case S_BOOLEAN:
+		if (p[0] == 'y') {
+			sym->def[def].tri = yes;
+			sym->flags |= def_flags;
+			break;
+		}
+		if (p[0] == 'n') {
+			sym->def[def].tri = no;
+			sym->flags |= def_flags;
+			break;
+		}
+		if (def != S_DEF_AUTO)
+			conf_warning("symbol value '%s' invalid for %s",
+				     p, sym->name);
+		return 1;
+	case S_STRING:
+		/* No escaping for S_DEF_AUTO (include/config/auto.conf) */
+		if (def != S_DEF_AUTO) {
+			if (*p++ != '"')
+				break;
+			for (p2 = p; (p2 = strpbrk(p2, "\"\\")); p2++) {
+				if (*p2 == '"') {
+					*p2 = 0;
+					break;
+				}
+				memmove(p2, p2 + 1, strlen(p2));
+			}
+			if (!p2) {
+				conf_warning("invalid string found");
+				return 1;
+			}
+		}
+		/* fall through */
+	case S_INT:
+	case S_HEX:
+		if (sym_string_valid(sym, p)) {
+			sym->def[def].val = xstrdup(p);
+			sym->flags |= def_flags;
+		} else {
+			if (def != S_DEF_AUTO)
+				conf_warning("symbol value '%s' invalid for %s",
+					     p, sym->name);
+			return 1;
+		}
+		break;
+	default:
+		;
+	}
+	return 0;
+}
+
+#define LINE_GROWTH 16
+static int add_byte(int c, char **lineptr, size_t slen, size_t *n)
+{
+	char *nline;
+	size_t new_size = slen + 1;
+	if (new_size > *n) {
+		new_size += LINE_GROWTH - 1;
+		new_size *= 2;
+		nline = xrealloc(*lineptr, new_size);
+		if (!nline)
+			return -1;
+
+		*lineptr = nline;
+		*n = new_size;
+	}
+
+	(*lineptr)[slen] = c;
+
+	return 0;
+}
+
+static ssize_t compat_getline(char **lineptr, size_t *n, FILE *stream)
+{
+	char *line = *lineptr;
+	size_t slen = 0;
+
+	for (;;) {
+		int c = getc(stream);
+
+		switch (c) {
+		case '\n':
+			if (add_byte(c, &line, slen, n) < 0)
+				goto e_out;
+			slen++;
+			/* fall through */
+		case EOF:
+			if (add_byte('\0', &line, slen, n) < 0)
+				goto e_out;
+			*lineptr = line;
+			if (slen == 0)
+				return -1;
+			return slen;
+		default:
+			if (add_byte(c, &line, slen, n) < 0)
+				goto e_out;
+			slen++;
+		}
+	}
+
+e_out:
+	line[slen-1] = '\0';
+	*lineptr = line;
+	return -1;
+}
+
+int conf_read_simple(const char *name, int def)
+{
+	FILE *in = NULL;
+	char   *line = NULL;
+	size_t  line_asize = 0;
+	char *p, *p2;
+	struct symbol *sym;
+	int i, def_flags;
+
+	if (name) {
+		in = zconf_fopen(name);
+	} else {
+		char *env;
+
+		name = conf_get_configname();
+		in = zconf_fopen(name);
+		if (in)
+			goto load;
+		conf_set_changed(true);
+
+		env = getenv("KCONFIG_DEFCONFIG_LIST");
+		if (!env)
+			return 1;
+
+		while (1) {
+			bool is_last;
+
+			while (isspace(*env))
+				env++;
+
+			if (!*env)
+				break;
+
+			p = env;
+			while (*p && !isspace(*p))
+				p++;
+
+			is_last = (*p == '\0');
+
+			*p = '\0';
+
+			in = zconf_fopen(env);
+			if (in) {
+				conf_message("using defaults found in %s",
+					     env);
+				goto load;
+			}
+
+			if (is_last)
+				break;
+
+			env = p + 1;
+		}
+	}
+	if (!in)
+		return 1;
+
+load:
+	conf_filename = name;
+	conf_lineno = 0;
+	conf_warnings = 0;
+
+	def_flags = SYMBOL_DEF << def;
+	for_all_symbols(i, sym) {
+		sym->flags |= SYMBOL_CHANGED;
+		sym->flags &= ~(def_flags|SYMBOL_VALID);
+		if (sym_is_choice(sym))
+			sym->flags |= def_flags;
+		switch (sym->type) {
+		case S_INT:
+		case S_HEX:
+		case S_STRING:
+			if (sym->def[def].val)
+				free(sym->def[def].val);
+			/* fall through */
+		default:
+			sym->def[def].val = NULL;
+			sym->def[def].tri = no;
+		}
+	}
+
+	while (compat_getline(&line, &line_asize, in) != -1) {
+		conf_lineno++;
+		sym = NULL;
+		if (line[0] == '#') {
+			if (memcmp(line + 2, CONFIG_, strlen(CONFIG_)))
+				continue;
+			p = strchr(line + 2 + strlen(CONFIG_), ' ');
+			if (!p)
+				continue;
+			*p++ = 0;
+			if (strncmp(p, "is not set", 10))
+				continue;
+			if (def == S_DEF_USER) {
+				sym = sym_find(line + 2 + strlen(CONFIG_));
+				if (!sym) {
+					conf_set_changed(true);
+					continue;
+				}
+			} else {
+				sym = sym_lookup(line + 2 + strlen(CONFIG_), 0);
+				if (sym->type == S_UNKNOWN)
+					sym->type = S_BOOLEAN;
+			}
+			if (sym->flags & def_flags) {
+				conf_warning("override: reassigning to symbol %s", sym->name);
+			}
+			switch (sym->type) {
+			case S_BOOLEAN:
+			case S_TRISTATE:
+				sym->def[def].tri = no;
+				sym->flags |= def_flags;
+				break;
+			default:
+				;
+			}
+		} else if (memcmp(line, CONFIG_, strlen(CONFIG_)) == 0) {
+			p = strchr(line + strlen(CONFIG_), '=');
+			if (!p)
+				continue;
+			*p++ = 0;
+			p2 = strchr(p, '\n');
+			if (p2) {
+				*p2-- = 0;
+				if (*p2 == '\r')
+					*p2 = 0;
+			}
+
+			sym = sym_find(line + strlen(CONFIG_));
+			if (!sym) {
+				if (def == S_DEF_AUTO)
+					/*
+					 * Reading from include/config/auto.conf
+					 * If CONFIG_FOO previously existed in
+					 * auto.conf but it is missing now,
+					 * include/config/FOO must be touched.
+					 */
+					conf_touch_dep(line + strlen(CONFIG_));
+				else
+					conf_set_changed(true);
+				continue;
+			}
+
+			if (sym->flags & def_flags) {
+				conf_warning("override: reassigning to symbol %s", sym->name);
+			}
+			if (conf_set_sym_val(sym, def, def_flags, p))
+				continue;
+		} else {
+			if (line[0] != '\r' && line[0] != '\n')
+				conf_warning("unexpected data: %.*s",
+					     (int)strcspn(line, "\r\n"), line);
+
+			continue;
+		}
+
+		if (sym && sym_is_choice_value(sym)) {
+			struct symbol *cs = prop_get_symbol(sym_get_choice_prop(sym));
+			switch (sym->def[def].tri) {
+			case no:
+				break;
+			case mod:
+				if (cs->def[def].tri == yes) {
+					conf_warning("%s creates inconsistent choice state", sym->name);
+					cs->flags &= ~def_flags;
+				}
+				break;
+			case yes:
+				if (cs->def[def].tri != no)
+					conf_warning("override: %s changes choice state", sym->name);
+				cs->def[def].val = sym;
+				break;
+			}
+			cs->def[def].tri = EXPR_OR(cs->def[def].tri, sym->def[def].tri);
+		}
+	}
+	free(line);
+	fclose(in);
+	return 0;
+}
+
+int conf_read(const char *name)
+{
+	struct symbol *sym;
+	int conf_unsaved = 0;
+	int i;
+
+	conf_set_changed(false);
+
+	if (conf_read_simple(name, S_DEF_USER)) {
+		sym_calc_value(modules_sym);
+		return 1;
+	}
+
+	sym_calc_value(modules_sym);
+
+	for_all_symbols(i, sym) {
+		sym_calc_value(sym);
+		if (sym_is_choice(sym) || (sym->flags & SYMBOL_NO_WRITE))
+			continue;
+		if (sym_has_value(sym) && (sym->flags & SYMBOL_WRITE)) {
+			/* check that calculated value agrees with saved value */
+			switch (sym->type) {
+			case S_BOOLEAN:
+			case S_TRISTATE:
+				if (sym->def[S_DEF_USER].tri == sym_get_tristate_value(sym))
+					continue;
+				break;
+			default:
+				if (!strcmp(sym->curr.val, sym->def[S_DEF_USER].val))
+					continue;
+				break;
+			}
+		} else if (!sym_has_value(sym) && !(sym->flags & SYMBOL_WRITE))
+			/* no previous value and not saved */
+			continue;
+		conf_unsaved++;
+		/* maybe print value in verbose mode... */
+	}
+
+	for_all_symbols(i, sym) {
+		if (sym_has_value(sym) && !sym_is_choice_value(sym)) {
+			/* Reset values of generates values, so they'll appear
+			 * as new, if they should become visible, but that
+			 * doesn't quite work if the Kconfig and the saved
+			 * configuration disagree.
+			 */
+			if (sym->visible == no && !conf_unsaved)
+				sym->flags &= ~SYMBOL_DEF_USER;
+			switch (sym->type) {
+			case S_STRING:
+			case S_INT:
+			case S_HEX:
+				/* Reset a string value if it's out of range */
+				if (sym_string_within_range(sym, sym->def[S_DEF_USER].val))
+					break;
+				sym->flags &= ~(SYMBOL_VALID|SYMBOL_DEF_USER);
+				conf_unsaved++;
+				break;
+			default:
+				break;
+			}
+		}
+	}
+
+	if (conf_warnings || conf_unsaved)
+		conf_set_changed(true);
+
+	return 0;
+}
+
+struct comment_style {
+	const char *decoration;
+	const char *prefix;
+	const char *postfix;
+};
+
+static const struct comment_style comment_style_pound = {
+	.decoration = "#",
+	.prefix = "#",
+	.postfix = "#",
+};
+
+static const struct comment_style comment_style_c = {
+	.decoration = " *",
+	.prefix = "/*",
+	.postfix = " */",
+};
+
+static void conf_write_heading(FILE *fp, const struct comment_style *cs)
+{
+	if (!cs)
+		return;
+
+	fprintf(fp, "%s\n", cs->prefix);
+
+	fprintf(fp, "%s Automatically generated file; DO NOT EDIT.\n",
+		cs->decoration);
+
+	fprintf(fp, "%s %s\n", cs->decoration, rootmenu.prompt->text);
+
+	fprintf(fp, "%s\n", cs->postfix);
+}
+
+/* The returned pointer must be freed on the caller side */
+static char *escape_string_value(const char *in)
+{
+	const char *p;
+	char *out;
+	size_t len;
+
+	len = strlen(in) + strlen("\"\"") + 1;
+
+	p = in;
+	while (1) {
+		p += strcspn(p, "\"\\");
+
+		if (p[0] == '\0')
+			break;
+
+		len++;
+		p++;
+	}
+
+	out = xmalloc(len);
+	out[0] = '\0';
+
+	strcat(out, "\"");
+
+	p = in;
+	while (1) {
+		len = strcspn(p, "\"\\");
+		strncat(out, p, len);
+		p += len;
+
+		if (p[0] == '\0')
+			break;
+
+		strcat(out, "\\");
+		strncat(out, p++, 1);
+	}
+
+	strcat(out, "\"");
+
+	return out;
+}
+
+enum output_n { OUTPUT_N, OUTPUT_N_AS_UNSET, OUTPUT_N_NONE };
+
+static void __print_symbol(FILE *fp, struct symbol *sym, enum output_n output_n,
+			   bool escape_string)
+{
+	const char *val;
+	char *escaped = NULL;
+
+	if (sym->type == S_UNKNOWN)
+		return;
+
+	val = sym_get_string_value(sym);
+
+	if ((sym->type == S_BOOLEAN || sym->type == S_TRISTATE) &&
+	    output_n != OUTPUT_N && *val == 'n') {
+		if (output_n == OUTPUT_N_AS_UNSET)
+			fprintf(fp, "# %s%s is not set\n", CONFIG_, sym->name);
+		return;
+	}
+
+	if (sym->type == S_STRING && escape_string) {
+		escaped = escape_string_value(val);
+		val = escaped;
+	}
+
+	fprintf(fp, "%s%s=%s\n", CONFIG_, sym->name, val);
+
+	free(escaped);
+}
+
+static void print_symbol_for_dotconfig(FILE *fp, struct symbol *sym)
+{
+	__print_symbol(fp, sym, OUTPUT_N_AS_UNSET, true);
+}
+
+static void print_symbol_for_autoconf(FILE *fp, struct symbol *sym)
+{
+	__print_symbol(fp, sym, OUTPUT_N_NONE, false);
+}
+
+void print_symbol_for_listconfig(struct symbol *sym)
+{
+	__print_symbol(stdout, sym, OUTPUT_N, true);
+}
+
+static void print_symbol_for_c(FILE *fp, struct symbol *sym)
+{
+	const char *val;
+	const char *sym_suffix = "";
+	const char *val_prefix = "";
+	char *escaped = NULL;
+
+	if (sym->type == S_UNKNOWN)
+		return;
+
+	val = sym_get_string_value(sym);
+
+	switch (sym->type) {
+	case S_BOOLEAN:
+	case S_TRISTATE:
+		switch (*val) {
+		case 'n':
+			return;
+		case 'm':
+			sym_suffix = "_MODULE";
+			/* fall through */
+		default:
+			val = "1";
+		}
+		break;
+	case S_HEX:
+		if (val[0] != '0' || (val[1] != 'x' && val[1] != 'X'))
+			val_prefix = "0x";
+		break;
+	case S_STRING:
+		escaped = escape_string_value(val);
+		val = escaped;
+	default:
+		break;
+	}
+
+	fprintf(fp, "#define %s%s%s %s%s\n", CONFIG_, sym->name, sym_suffix,
+		val_prefix, val);
+
+	free(escaped);
+}
+
+static void print_symbol_for_rustccfg(FILE *fp, struct symbol *sym)
+{
+	const char *val;
+	const char *val_prefix = "";
+	char *val_prefixed = NULL;
+	size_t val_prefixed_len;
+	char *escaped = NULL;
+
+	if (sym->type == S_UNKNOWN)
+		return;
+
+	val = sym_get_string_value(sym);
+
+	switch (sym->type) {
+	case S_BOOLEAN:
+	case S_TRISTATE:
+		/*
+		 * We do not care about disabled ones, i.e. no need for
+		 * what otherwise are "comments" in other printers.
+		 */
+		if (*val == 'n')
+			return;
+
+		/*
+		 * To have similar functionality to the C macro `IS_ENABLED()`
+		 * we provide an empty `--cfg CONFIG_X` here in both `y`
+		 * and `m` cases.
+		 *
+		 * Then, the common `fprintf()` below will also give us
+		 * a `--cfg CONFIG_X="y"` or `--cfg CONFIG_X="m"`, which can
+		 * be used as the equivalent of `IS_BUILTIN()`/`IS_MODULE()`.
+		 */
+		fprintf(fp, "--cfg=%s%s\n", CONFIG_, sym->name);
+		break;
+	case S_HEX:
+		if (val[0] != '0' || (val[1] != 'x' && val[1] != 'X'))
+			val_prefix = "0x";
+		break;
+	default:
+		break;
+	}
+
+	if (strlen(val_prefix) > 0) {
+		val_prefixed_len = strlen(val) + strlen(val_prefix) + 1;
+		val_prefixed = xmalloc(val_prefixed_len);
+		snprintf(val_prefixed, val_prefixed_len, "%s%s", val_prefix, val);
+		val = val_prefixed;
+	}
+
+	/* All values get escaped: the `--cfg` option only takes strings */
+	escaped = escape_string_value(val);
+	val = escaped;
+
+	fprintf(fp, "--cfg=%s%s=%s\n", CONFIG_, sym->name, val);
+
+	free(escaped);
+	free(val_prefixed);
+}
+
+/*
+ * Write out a minimal config.
+ * All values that has default values are skipped as this is redundant.
+ */
+int conf_write_defconfig(const char *filename)
+{
+	struct symbol *sym;
+	struct menu *menu;
+	FILE *out;
+
+	out = fopen(filename, "w");
+	if (!out)
+		return 1;
+
+	sym_clear_all_valid();
+
+	/* Traverse all menus to find all relevant symbols */
+	menu = rootmenu.list;
+
+	while (menu != NULL)
+	{
+		sym = menu->sym;
+		if (sym == NULL) {
+			if (!menu_is_visible(menu))
+				goto next_menu;
+		} else if (!sym_is_choice(sym)) {
+			sym_calc_value(sym);
+			if (!(sym->flags & SYMBOL_WRITE))
+				goto next_menu;
+			sym->flags &= ~SYMBOL_WRITE;
+			/* If we cannot change the symbol - skip */
+			if (!sym_is_changeable(sym))
+				goto next_menu;
+			/* If symbol equals to default value - skip */
+			if (strcmp(sym_get_string_value(sym), sym_get_string_default(sym)) == 0)
+				goto next_menu;
+
+			/*
+			 * If symbol is a choice value and equals to the
+			 * default for a choice - skip.
+			 * But only if value is bool and equal to "y" and
+			 * choice is not "optional".
+			 * (If choice is "optional" then all values can be "n")
+			 */
+			if (sym_is_choice_value(sym)) {
+				struct symbol *cs;
+				struct symbol *ds;
+
+				cs = prop_get_symbol(sym_get_choice_prop(sym));
+				ds = sym_choice_default(cs);
+				if (!sym_is_optional(cs) && sym == ds) {
+					if ((sym->type == S_BOOLEAN) &&
+					    sym_get_tristate_value(sym) == yes)
+						goto next_menu;
+				}
+			}
+			print_symbol_for_dotconfig(out, sym);
+		}
+next_menu:
+		if (menu->list != NULL) {
+			menu = menu->list;
+		}
+		else if (menu->next != NULL) {
+			menu = menu->next;
+		} else {
+			while ((menu = menu->parent)) {
+				if (menu->next != NULL) {
+					menu = menu->next;
+					break;
+				}
+			}
+		}
+	}
+	fclose(out);
+	return 0;
+}
+
+int conf_write(const char *name)
+{
+	FILE *out;
+	struct symbol *sym;
+	struct menu *menu;
+	const char *str;
+	char tmpname[PATH_MAX + 1], oldname[PATH_MAX + 1];
+	char *env;
+	int i;
+	bool need_newline = false;
+
+	if (!name)
+		name = conf_get_configname();
+
+	if (!*name) {
+		fprintf(stderr, "config name is empty\n");
+		return -1;
+	}
+
+	if (is_dir(name)) {
+		fprintf(stderr, "%s: Is a directory\n", name);
+		return -1;
+	}
+
+	if (make_parent_dir(name))
+		return -1;
+
+	env = getenv("KCONFIG_OVERWRITECONFIG");
+	if (env && *env) {
+		*tmpname = 0;
+		out = fopen(name, "w");
+	} else {
+		snprintf(tmpname, sizeof(tmpname), "%s.%d.tmp",
+			 name, (int)getpid());
+		out = fopen(tmpname, "w");
+	}
+	if (!out)
+		return 1;
+
+	conf_write_heading(out, &comment_style_pound);
+
+	if (!conf_get_changed())
+		sym_clear_all_valid();
+
+	menu = rootmenu.list;
+	while (menu) {
+		sym = menu->sym;
+		if (!sym) {
+			if (!menu_is_visible(menu))
+				goto next;
+			str = menu_get_prompt(menu);
+			fprintf(out, "\n"
+				     "#\n"
+				     "# %s\n"
+				     "#\n", str);
+			need_newline = false;
+		} else if (!(sym->flags & SYMBOL_CHOICE) &&
+			   !(sym->flags & SYMBOL_WRITTEN)) {
+			sym_calc_value(sym);
+			if (!(sym->flags & SYMBOL_WRITE))
+				goto next;
+			if (need_newline) {
+				fprintf(out, "\n");
+				need_newline = false;
+			}
+			sym->flags |= SYMBOL_WRITTEN;
+			print_symbol_for_dotconfig(out, sym);
+		}
+
+next:
+		if (menu->list) {
+			menu = menu->list;
+			continue;
+		}
+
+end_check:
+		if (!menu->sym && menu_is_visible(menu) && menu != &rootmenu &&
+		    menu->prompt->type == P_MENU) {
+			fprintf(out, "# end of %s\n", menu_get_prompt(menu));
+			need_newline = true;
+		}
+
+		if (menu->next) {
+			menu = menu->next;
+		} else {
+			menu = menu->parent;
+			if (menu)
+				goto end_check;
+		}
+	}
+	fclose(out);
+
+	for_all_symbols(i, sym)
+		sym->flags &= ~SYMBOL_WRITTEN;
+
+	if (*tmpname) {
+		if (is_same(name, tmpname)) {
+			conf_message("No change to %s", name);
+			unlink(tmpname);
+			conf_set_changed(false);
+			return 0;
+		}
+
+		snprintf(oldname, sizeof(oldname), "%s.old", name);
+		rename(name, oldname);
+		if (rename(tmpname, name))
+			return 1;
+	}
+
+	conf_message("configuration written to %s", name);
+
+	conf_set_changed(false);
+
+	return 0;
+}
+
+/* write a dependency file as used by kbuild to track dependencies */
+static int conf_write_autoconf_cmd(const char *autoconf_name)
+{
+	char name[PATH_MAX], tmp[PATH_MAX];
+	struct file *file;
+	FILE *out;
+	int ret;
+
+	ret = snprintf(name, sizeof(name), "%s.cmd", autoconf_name);
+	if (ret >= sizeof(name)) /* check truncation */
+		return -1;
+
+	if (make_parent_dir(name))
+		return -1;
+
+	ret = snprintf(tmp, sizeof(tmp), "%s.cmd.tmp", autoconf_name);
+	if (ret >= sizeof(tmp)) /* check truncation */
+		return -1;
+
+	out = fopen(tmp, "w");
+	if (!out) {
+		perror("fopen");
+		return -1;
+	}
+
+	fprintf(out, "deps_config := \\\n");
+	for (file = file_list; file; file = file->next)
+		fprintf(out, "\t%s \\\n", file->name);
+
+	fprintf(out, "\n%s: $(deps_config)\n\n", autoconf_name);
+
+	env_write_dep(out, autoconf_name);
+
+	fprintf(out, "\n$(deps_config): ;\n");
+
+	fflush(out);
+	ret = ferror(out); /* error check for all fprintf() calls */
+	fclose(out);
+	if (ret)
+		return -1;
+
+	if (rename(tmp, name)) {
+		perror("rename");
+		return -1;
+	}
+
+	return 0;
+}
+
+static int conf_touch_deps(void)
+{
+	const char *name, *tmp;
+	struct symbol *sym;
+	int res, i;
+
+	name = conf_get_autoconfig_name();
+	tmp = strrchr(name, '/');
+	depfile_prefix_len = tmp ? tmp - name + 1 : 0;
+	if (depfile_prefix_len + 1 > sizeof(depfile_path))
+		return -1;
+
+	strncpy(depfile_path, name, depfile_prefix_len);
+	depfile_path[depfile_prefix_len] = 0;
+
+	conf_read_simple(name, S_DEF_AUTO);
+	sym_calc_value(modules_sym);
+
+	for_all_symbols(i, sym) {
+		sym_calc_value(sym);
+		if ((sym->flags & SYMBOL_NO_WRITE) || !sym->name)
+			continue;
+		if (sym->flags & SYMBOL_WRITE) {
+			if (sym->flags & SYMBOL_DEF_AUTO) {
+				/*
+				 * symbol has old and new value,
+				 * so compare them...
+				 */
+				switch (sym->type) {
+				case S_BOOLEAN:
+				case S_TRISTATE:
+					if (sym_get_tristate_value(sym) ==
+					    sym->def[S_DEF_AUTO].tri)
+						continue;
+					break;
+				case S_STRING:
+				case S_HEX:
+				case S_INT:
+					if (!strcmp(sym_get_string_value(sym),
+						    sym->def[S_DEF_AUTO].val))
+						continue;
+					break;
+				default:
+					break;
+				}
+			} else {
+				/*
+				 * If there is no old value, only 'no' (unset)
+				 * is allowed as new value.
+				 */
+				switch (sym->type) {
+				case S_BOOLEAN:
+				case S_TRISTATE:
+					if (sym_get_tristate_value(sym) == no)
+						continue;
+					break;
+				default:
+					break;
+				}
+			}
+		} else if (!(sym->flags & SYMBOL_DEF_AUTO))
+			/* There is neither an old nor a new value. */
+			continue;
+		/* else
+		 *	There is an old value, but no new value ('no' (unset)
+		 *	isn't saved in auto.conf, so the old value is always
+		 *	different from 'no').
+		 */
+
+		res = conf_touch_dep(sym->name);
+		if (res)
+			return res;
+	}
+
+	return 0;
+}
+
+static int __conf_write_autoconf(const char *filename,
+				 void (*print_symbol)(FILE *, struct symbol *),
+				 const struct comment_style *comment_style)
+{
+	char tmp[PATH_MAX];
+	FILE *file;
+	struct symbol *sym;
+	int ret, i;
+
+	if (make_parent_dir(filename))
+		return -1;
+
+	ret = snprintf(tmp, sizeof(tmp), "%s.tmp", filename);
+	if (ret >= sizeof(tmp)) /* check truncation */
+		return -1;
+
+	file = fopen(tmp, "w");
+	if (!file) {
+		perror("fopen");
+		return -1;
+	}
+
+	conf_write_heading(file, comment_style);
+
+	for_all_symbols(i, sym)
+		if ((sym->flags & SYMBOL_WRITE) && sym->name)
+			print_symbol(file, sym);
+
+	fflush(file);
+	/* check possible errors in conf_write_heading() and print_symbol() */
+	ret = ferror(file);
+	fclose(file);
+	if (ret)
+		return -1;
+
+	if (rename(tmp, filename)) {
+		perror("rename");
+		return -1;
+	}
+
+	return 0;
+}
+
+int conf_write_autoconf(int overwrite)
+{
+	struct symbol *sym;
+	const char *autoconf_name = conf_get_autoconfig_name();
+	int ret, i;
+
+	if (!overwrite && is_present(autoconf_name))
+		return 0;
+
+	ret = conf_write_autoconf_cmd(autoconf_name);
+	if (ret)
+		return -1;
+
+	if (conf_touch_deps())
+		return 1;
+
+	for_all_symbols(i, sym)
+		sym_calc_value(sym);
+
+	ret = __conf_write_autoconf(conf_get_autoheader_name(),
+				    print_symbol_for_c,
+				    &comment_style_c);
+	if (ret)
+		return ret;
+
+	ret = __conf_write_autoconf(conf_get_rustccfg_name(),
+				    print_symbol_for_rustccfg,
+				    NULL);
+	if (ret)
+		return ret;
+
+	/*
+	 * Create include/config/auto.conf. This must be the last step because
+	 * Kbuild has a dependency on auto.conf and this marks the successful
+	 * completion of the previous steps.
+	 */
+	ret = __conf_write_autoconf(conf_get_autoconfig_name(),
+				    print_symbol_for_autoconf,
+				    &comment_style_pound);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static bool conf_changed;
+static void (*conf_changed_callback)(void);
+
+void conf_set_changed(bool val)
+{
+	if (conf_changed_callback && conf_changed != val)
+		conf_changed_callback();
+
+	conf_changed = val;
+}
+
+bool conf_get_changed(void)
+{
+	return conf_changed;
+}
+
+void conf_set_changed_callback(void (*fn)(void))
+{
+	conf_changed_callback = fn;
+}
+
+void set_all_choice_values(struct symbol *csym)
+{
+	struct property *prop;
+	struct symbol *sym;
+	struct expr *e;
+
+	prop = sym_get_choice_prop(csym);
+
+	/*
+	 * Set all non-assinged choice values to no
+	 */
+	expr_list_for_each_sym(prop->expr, e, sym) {
+		if (!sym_has_value(sym))
+			sym->def[S_DEF_USER].tri = no;
+	}
+	csym->flags |= SYMBOL_DEF_USER;
+	/* clear VALID to get value calculated */
+	csym->flags &= ~(SYMBOL_VALID | SYMBOL_NEED_SET_CHOICE_VALUES);
+}