xref: /openbmc/linux/scripts/kconfig/confdata.c (revision aac28965) 
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (C) 2002 Roman Zippel <zippel@linux-m68k.org>
4  */
5 
6 #include <sys/mman.h>
7 #include <sys/stat.h>
8 #include <sys/types.h>
9 #include <ctype.h>
10 #include <errno.h>
11 #include <fcntl.h>
12 #include <limits.h>
13 #include <stdarg.h>
14 #include <stdbool.h>
15 #include <stdio.h>
16 #include <stdlib.h>
17 #include <string.h>
18 #include <time.h>
19 #include <unistd.h>
20 
21 #include "lkc.h"
22 
23 /* return true if 'path' exists, false otherwise */
24 static bool is_present(const char *path)
25 {
26 	struct stat st;
27 
28 	return !stat(path, &st);
29 }
30 
31 /* return true if 'path' exists and it is a directory, false otherwise */
32 static bool is_dir(const char *path)
33 {
34 	struct stat st;
35 
36 	if (stat(path, &st))
37 		return false;
38 
39 	return S_ISDIR(st.st_mode);
40 }
41 
42 /* return true if the given two files are the same, false otherwise */
43 static bool is_same(const char *file1, const char *file2)
44 {
45 	int fd1, fd2;
46 	struct stat st1, st2;
47 	void *map1, *map2;
48 	bool ret = false;
49 
50 	fd1 = open(file1, O_RDONLY);
51 	if (fd1 < 0)
52 		return ret;
53 
54 	fd2 = open(file2, O_RDONLY);
55 	if (fd2 < 0)
56 		goto close1;
57 
58 	ret = fstat(fd1, &st1);
59 	if (ret)
60 		goto close2;
61 	ret = fstat(fd2, &st2);
62 	if (ret)
63 		goto close2;
64 
65 	if (st1.st_size != st2.st_size)
66 		goto close2;
67 
68 	map1 = mmap(NULL, st1.st_size, PROT_READ, MAP_PRIVATE, fd1, 0);
69 	if (map1 == MAP_FAILED)
70 		goto close2;
71 
72 	map2 = mmap(NULL, st2.st_size, PROT_READ, MAP_PRIVATE, fd2, 0);
73 	if (map2 == MAP_FAILED)
74 		goto close2;
75 
76 	if (bcmp(map1, map2, st1.st_size))
77 		goto close2;
78 
79 	ret = true;
80 close2:
81 	close(fd2);
82 close1:
83 	close(fd1);
84 
85 	return ret;
86 }
87 
88 /*
89  * Create the parent directory of the given path.
90  *
91  * For example, if 'include/config/auto.conf' is given, create 'include/config'.
92  */
93 static int make_parent_dir(const char *path)
94 {
95 	char tmp[PATH_MAX + 1];
96 	char *p;
97 
98 	strncpy(tmp, path, sizeof(tmp));
99 	tmp[sizeof(tmp) - 1] = 0;
100 
101 	/* Remove the base name. Just return if nothing is left */
102 	p = strrchr(tmp, '/');
103 	if (!p)
104 		return 0;
105 	*(p + 1) = 0;
106 
107 	/* Just in case it is an absolute path */
108 	p = tmp;
109 	while (*p == '/')
110 		p++;
111 
112 	while ((p = strchr(p, '/'))) {
113 		*p = 0;
114 
115 		/* skip if the directory exists */
116 		if (!is_dir(tmp) && mkdir(tmp, 0755))
117 			return -1;
118 
119 		*p = '/';
120 		while (*p == '/')
121 			p++;
122 	}
123 
124 	return 0;
125 }
126 
127 static char depfile_path[PATH_MAX];
128 static size_t depfile_prefix_len;
129 
130 /* touch depfile for symbol 'name' */
131 static int conf_touch_dep(const char *name)
132 {
133 	int fd;
134 
135 	/* check overflow: prefix + name + '\0' must fit in buffer. */
136 	if (depfile_prefix_len + strlen(name) + 1 > sizeof(depfile_path))
137 		return -1;
138 
139 	strcpy(depfile_path + depfile_prefix_len, name);
140 
141 	fd = open(depfile_path, O_WRONLY | O_CREAT | O_TRUNC, 0644);
142 	if (fd == -1)
143 		return -1;
144 	close(fd);
145 
146 	return 0;
147 }
148 
149 static void conf_warning(const char *fmt, ...)
150 	__attribute__ ((format (printf, 1, 2)));
151 
152 static void conf_message(const char *fmt, ...)
153 	__attribute__ ((format (printf, 1, 2)));
154 
155 static const char *conf_filename;
156 static int conf_lineno, conf_warnings;
157 
158 static void conf_warning(const char *fmt, ...)
159 {
160 	va_list ap;
161 	va_start(ap, fmt);
162 	fprintf(stderr, "%s:%d:warning: ", conf_filename, conf_lineno);
163 	vfprintf(stderr, fmt, ap);
164 	fprintf(stderr, "\n");
165 	va_end(ap);
166 	conf_warnings++;
167 }
168 
169 static void conf_default_message_callback(const char *s)
170 {
171 	printf("#\n# ");
172 	printf("%s", s);
173 	printf("\n#\n");
174 }
175 
176 static void (*conf_message_callback)(const char *s) =
177 	conf_default_message_callback;
178 void conf_set_message_callback(void (*fn)(const char *s))
179 {
180 	conf_message_callback = fn;
181 }
182 
183 static void conf_message(const char *fmt, ...)
184 {
185 	va_list ap;
186 	char buf[4096];
187 
188 	if (!conf_message_callback)
189 		return;
190 
191 	va_start(ap, fmt);
192 
193 	vsnprintf(buf, sizeof(buf), fmt, ap);
194 	conf_message_callback(buf);
195 	va_end(ap);
196 }
197 
198 const char *conf_get_configname(void)
199 {
200 	char *name = getenv("KCONFIG_CONFIG");
201 
202 	return name ? name : ".config";
203 }
204 
205 static const char *conf_get_autoconfig_name(void)
206 {
207 	char *name = getenv("KCONFIG_AUTOCONFIG");
208 
209 	return name ? name : "include/config/auto.conf";
210 }
211 
212 static const char *conf_get_autoheader_name(void)
213 {
214 	char *name = getenv("KCONFIG_AUTOHEADER");
215 
216 	return name ? name : "include/generated/autoconf.h";
217 }
218 
219 static int conf_set_sym_val(struct symbol *sym, int def, int def_flags, char *p)
220 {
221 	char *p2;
222 
223 	switch (sym->type) {
224 	case S_TRISTATE:
225 		if (p[0] == 'm') {
226 			sym->def[def].tri = mod;
227 			sym->flags |= def_flags;
228 			break;
229 		}
230 		/* fall through */
231 	case S_BOOLEAN:
232 		if (p[0] == 'y') {
233 			sym->def[def].tri = yes;
234 			sym->flags |= def_flags;
235 			break;
236 		}
237 		if (p[0] == 'n') {
238 			sym->def[def].tri = no;
239 			sym->flags |= def_flags;
240 			break;
241 		}
242 		if (def != S_DEF_AUTO)
243 			conf_warning("symbol value '%s' invalid for %s",
244 				     p, sym->name);
245 		return 1;
246 	case S_STRING:
247 		/* No escaping for S_DEF_AUTO (include/config/auto.conf) */
248 		if (def != S_DEF_AUTO) {
249 			if (*p++ != '"')
250 				break;
251 			for (p2 = p; (p2 = strpbrk(p2, "\"\\")); p2++) {
252 				if (*p2 == '"') {
253 					*p2 = 0;
254 					break;
255 				}
256 				memmove(p2, p2 + 1, strlen(p2));
257 			}
258 			if (!p2) {
259 				conf_warning("invalid string found");
260 				return 1;
261 			}
262 		}
263 		/* fall through */
264 	case S_INT:
265 	case S_HEX:
266 		if (sym_string_valid(sym, p)) {
267 			sym->def[def].val = xstrdup(p);
268 			sym->flags |= def_flags;
269 		} else {
270 			if (def != S_DEF_AUTO)
271 				conf_warning("symbol value '%s' invalid for %s",
272 					     p, sym->name);
273 			return 1;
274 		}
275 		break;
276 	default:
277 		;
278 	}
279 	return 0;
280 }
281 
282 #define LINE_GROWTH 16
283 static int add_byte(int c, char **lineptr, size_t slen, size_t *n)
284 {
285 	char *nline;
286 	size_t new_size = slen + 1;
287 	if (new_size > *n) {
288 		new_size += LINE_GROWTH - 1;
289 		new_size *= 2;
290 		nline = xrealloc(*lineptr, new_size);
291 		if (!nline)
292 			return -1;
293 
294 		*lineptr = nline;
295 		*n = new_size;
296 	}
297 
298 	(*lineptr)[slen] = c;
299 
300 	return 0;
301 }
302 
303 static ssize_t compat_getline(char **lineptr, size_t *n, FILE *stream)
304 {
305 	char *line = *lineptr;
306 	size_t slen = 0;
307 
308 	for (;;) {
309 		int c = getc(stream);
310 
311 		switch (c) {
312 		case '\n':
313 			if (add_byte(c, &line, slen, n) < 0)
314 				goto e_out;
315 			slen++;
316 			/* fall through */
317 		case EOF:
318 			if (add_byte('\0', &line, slen, n) < 0)
319 				goto e_out;
320 			*lineptr = line;
321 			if (slen == 0)
322 				return -1;
323 			return slen;
324 		default:
325 			if (add_byte(c, &line, slen, n) < 0)
326 				goto e_out;
327 			slen++;
328 		}
329 	}
330 
331 e_out:
332 	line[slen-1] = '\0';
333 	*lineptr = line;
334 	return -1;
335 }
336 
337 int conf_read_simple(const char *name, int def)
338 {
339 	FILE *in = NULL;
340 	char   *line = NULL;
341 	size_t  line_asize = 0;
342 	char *p, *p2;
343 	struct symbol *sym;
344 	int i, def_flags;
345 
346 	if (name) {
347 		in = zconf_fopen(name);
348 	} else {
349 		char *env;
350 
351 		name = conf_get_configname();
352 		in = zconf_fopen(name);
353 		if (in)
354 			goto load;
355 		conf_set_changed(true);
356 
357 		env = getenv("KCONFIG_DEFCONFIG_LIST");
358 		if (!env)
359 			return 1;
360 
361 		while (1) {
362 			bool is_last;
363 
364 			while (isspace(*env))
365 				env++;
366 
367 			if (!*env)
368 				break;
369 
370 			p = env;
371 			while (*p && !isspace(*p))
372 				p++;
373 
374 			is_last = (*p == '\0');
375 
376 			*p = '\0';
377 
378 			in = zconf_fopen(env);
379 			if (in) {
380 				conf_message("using defaults found in %s",
381 					     env);
382 				goto load;
383 			}
384 
385 			if (is_last)
386 				break;
387 
388 			env = p + 1;
389 		}
390 	}
391 	if (!in)
392 		return 1;
393 
394 load:
395 	conf_filename = name;
396 	conf_lineno = 0;
397 	conf_warnings = 0;
398 
399 	def_flags = SYMBOL_DEF << def;
400 	for_all_symbols(i, sym) {
401 		sym->flags |= SYMBOL_CHANGED;
402 		sym->flags &= ~(def_flags|SYMBOL_VALID);
403 		if (sym_is_choice(sym))
404 			sym->flags |= def_flags;
405 		switch (sym->type) {
406 		case S_INT:
407 		case S_HEX:
408 		case S_STRING:
409 			if (sym->def[def].val)
410 				free(sym->def[def].val);
411 			/* fall through */
412 		default:
413 			sym->def[def].val = NULL;
414 			sym->def[def].tri = no;
415 		}
416 	}
417 
418 	while (compat_getline(&line, &line_asize, in) != -1) {
419 		conf_lineno++;
420 		sym = NULL;
421 		if (line[0] == '#') {
422 			if (memcmp(line + 2, CONFIG_, strlen(CONFIG_)))
423 				continue;
424 			p = strchr(line + 2 + strlen(CONFIG_), ' ');
425 			if (!p)
426 				continue;
427 			*p++ = 0;
428 			if (strncmp(p, "is not set", 10))
429 				continue;
430 			if (def == S_DEF_USER) {
431 				sym = sym_find(line + 2 + strlen(CONFIG_));
432 				if (!sym) {
433 					conf_set_changed(true);
434 					continue;
435 				}
436 			} else {
437 				sym = sym_lookup(line + 2 + strlen(CONFIG_), 0);
438 				if (sym->type == S_UNKNOWN)
439 					sym->type = S_BOOLEAN;
440 			}
441 			if (sym->flags & def_flags) {
442 				conf_warning("override: reassigning to symbol %s", sym->name);
443 			}
444 			switch (sym->type) {
445 			case S_BOOLEAN:
446 			case S_TRISTATE:
447 				sym->def[def].tri = no;
448 				sym->flags |= def_flags;
449 				break;
450 			default:
451 				;
452 			}
453 		} else if (memcmp(line, CONFIG_, strlen(CONFIG_)) == 0) {
454 			p = strchr(line + strlen(CONFIG_), '=');
455 			if (!p)
456 				continue;
457 			*p++ = 0;
458 			p2 = strchr(p, '\n');
459 			if (p2) {
460 				*p2-- = 0;
461 				if (*p2 == '\r')
462 					*p2 = 0;
463 			}
464 
465 			sym = sym_find(line + strlen(CONFIG_));
466 			if (!sym) {
467 				if (def == S_DEF_AUTO)
468 					/*
469 					 * Reading from include/config/auto.conf
470 					 * If CONFIG_FOO previously existed in
471 					 * auto.conf but it is missing now,
472 					 * include/config/FOO must be touched.
473 					 */
474 					conf_touch_dep(line + strlen(CONFIG_));
475 				else
476 					conf_set_changed(true);
477 				continue;
478 			}
479 
480 			if (sym->flags & def_flags) {
481 				conf_warning("override: reassigning to symbol %s", sym->name);
482 			}
483 			if (conf_set_sym_val(sym, def, def_flags, p))
484 				continue;
485 		} else {
486 			if (line[0] != '\r' && line[0] != '\n')
487 				conf_warning("unexpected data: %.*s",
488 					     (int)strcspn(line, "\r\n"), line);
489 
490 			continue;
491 		}
492 
493 		if (sym && sym_is_choice_value(sym)) {
494 			struct symbol *cs = prop_get_symbol(sym_get_choice_prop(sym));
495 			switch (sym->def[def].tri) {
496 			case no:
497 				break;
498 			case mod:
499 				if (cs->def[def].tri == yes) {
500 					conf_warning("%s creates inconsistent choice state", sym->name);
501 					cs->flags &= ~def_flags;
502 				}
503 				break;
504 			case yes:
505 				if (cs->def[def].tri != no)
506 					conf_warning("override: %s changes choice state", sym->name);
507 				cs->def[def].val = sym;
508 				break;
509 			}
510 			cs->def[def].tri = EXPR_OR(cs->def[def].tri, sym->def[def].tri);
511 		}
512 	}
513 	free(line);
514 	fclose(in);
515 	return 0;
516 }
517 
518 int conf_read(const char *name)
519 {
520 	struct symbol *sym;
521 	int conf_unsaved = 0;
522 	int i;
523 
524 	conf_set_changed(false);
525 
526 	if (conf_read_simple(name, S_DEF_USER)) {
527 		sym_calc_value(modules_sym);
528 		return 1;
529 	}
530 
531 	sym_calc_value(modules_sym);
532 
533 	for_all_symbols(i, sym) {
534 		sym_calc_value(sym);
535 		if (sym_is_choice(sym) || (sym->flags & SYMBOL_NO_WRITE))
536 			continue;
537 		if (sym_has_value(sym) && (sym->flags & SYMBOL_WRITE)) {
538 			/* check that calculated value agrees with saved value */
539 			switch (sym->type) {
540 			case S_BOOLEAN:
541 			case S_TRISTATE:
542 				if (sym->def[S_DEF_USER].tri == sym_get_tristate_value(sym))
543 					continue;
544 				break;
545 			default:
546 				if (!strcmp(sym->curr.val, sym->def[S_DEF_USER].val))
547 					continue;
548 				break;
549 			}
550 		} else if (!sym_has_value(sym) && !(sym->flags & SYMBOL_WRITE))
551 			/* no previous value and not saved */
552 			continue;
553 		conf_unsaved++;
554 		/* maybe print value in verbose mode... */
555 	}
556 
557 	for_all_symbols(i, sym) {
558 		if (sym_has_value(sym) && !sym_is_choice_value(sym)) {
559 			/* Reset values of generates values, so they'll appear
560 			 * as new, if they should become visible, but that
561 			 * doesn't quite work if the Kconfig and the saved
562 			 * configuration disagree.
563 			 */
564 			if (sym->visible == no && !conf_unsaved)
565 				sym->flags &= ~SYMBOL_DEF_USER;
566 			switch (sym->type) {
567 			case S_STRING:
568 			case S_INT:
569 			case S_HEX:
570 				/* Reset a string value if it's out of range */
571 				if (sym_string_within_range(sym, sym->def[S_DEF_USER].val))
572 					break;
573 				sym->flags &= ~(SYMBOL_VALID|SYMBOL_DEF_USER);
574 				conf_unsaved++;
575 				break;
576 			default:
577 				break;
578 			}
579 		}
580 	}
581 
582 	if (conf_warnings || conf_unsaved)
583 		conf_set_changed(true);
584 
585 	return 0;
586 }
587 
588 struct comment_style {
589 	const char *decoration;
590 	const char *prefix;
591 	const char *postfix;
592 };
593 
594 static const struct comment_style comment_style_pound = {
595 	.decoration = "#",
596 	.prefix = "#",
597 	.postfix = "#",
598 };
599 
600 static const struct comment_style comment_style_c = {
601 	.decoration = " *",
602 	.prefix = "/*",
603 	.postfix = " */",
604 };
605 
606 static void conf_write_heading(FILE *fp, const struct comment_style *cs)
607 {
608 	fprintf(fp, "%s\n", cs->prefix);
609 
610 	fprintf(fp, "%s Automatically generated file; DO NOT EDIT.\n",
611 		cs->decoration);
612 
613 	fprintf(fp, "%s %s\n", cs->decoration, rootmenu.prompt->text);
614 
615 	fprintf(fp, "%s\n", cs->postfix);
616 }
617 
618 /* The returned pointer must be freed on the caller side */
619 static char *escape_string_value(const char *in)
620 {
621 	const char *p;
622 	char *out;
623 	size_t len;
624 
625 	len = strlen(in) + strlen("\"\"") + 1;
626 
627 	p = in;
628 	while (1) {
629 		p += strcspn(p, "\"\\");
630 
631 		if (p[0] == '\0')
632 			break;
633 
634 		len++;
635 		p++;
636 	}
637 
638 	out = xmalloc(len);
639 	out[0] = '\0';
640 
641 	strcat(out, "\"");
642 
643 	p = in;
644 	while (1) {
645 		len = strcspn(p, "\"\\");
646 		strncat(out, p, len);
647 		p += len;
648 
649 		if (p[0] == '\0')
650 			break;
651 
652 		strcat(out, "\\");
653 		strncat(out, p++, 1);
654 	}
655 
656 	strcat(out, "\"");
657 
658 	return out;
659 }
660 
661 enum output_n { OUTPUT_N, OUTPUT_N_AS_UNSET, OUTPUT_N_NONE };
662 
663 static void __print_symbol(FILE *fp, struct symbol *sym, enum output_n output_n,
664 			   bool escape_string)
665 {
666 	const char *val;
667 	char *escaped = NULL;
668 
669 	if (sym->type == S_UNKNOWN)
670 		return;
671 
672 	val = sym_get_string_value(sym);
673 
674 	if ((sym->type == S_BOOLEAN || sym->type == S_TRISTATE) &&
675 	    output_n != OUTPUT_N && *val == 'n') {
676 		if (output_n == OUTPUT_N_AS_UNSET)
677 			fprintf(fp, "# %s%s is not set\n", CONFIG_, sym->name);
678 		return;
679 	}
680 
681 	if (sym->type == S_STRING && escape_string) {
682 		escaped = escape_string_value(val);
683 		val = escaped;
684 	}
685 
686 	fprintf(fp, "%s%s=%s\n", CONFIG_, sym->name, val);
687 
688 	free(escaped);
689 }
690 
691 static void print_symbol_for_dotconfig(FILE *fp, struct symbol *sym)
692 {
693 	__print_symbol(fp, sym, OUTPUT_N_AS_UNSET, true);
694 }
695 
696 static void print_symbol_for_autoconf(FILE *fp, struct symbol *sym)
697 {
698 	__print_symbol(fp, sym, OUTPUT_N_NONE, false);
699 }
700 
701 void print_symbol_for_listconfig(struct symbol *sym)
702 {
703 	__print_symbol(stdout, sym, OUTPUT_N, true);
704 }
705 
706 static void print_symbol_for_c(FILE *fp, struct symbol *sym)
707 {
708 	const char *val;
709 	const char *sym_suffix = "";
710 	const char *val_prefix = "";
711 	char *escaped = NULL;
712 
713 	if (sym->type == S_UNKNOWN)
714 		return;
715 
716 	val = sym_get_string_value(sym);
717 
718 	switch (sym->type) {
719 	case S_BOOLEAN:
720 	case S_TRISTATE:
721 		switch (*val) {
722 		case 'n':
723 			return;
724 		case 'm':
725 			sym_suffix = "_MODULE";
726 			/* fall through */
727 		default:
728 			val = "1";
729 		}
730 		break;
731 	case S_HEX:
732 		if (val[0] != '0' || (val[1] != 'x' && val[1] != 'X'))
733 			val_prefix = "0x";
734 		break;
735 	case S_STRING:
736 		escaped = escape_string_value(val);
737 		val = escaped;
738 	default:
739 		break;
740 	}
741 
742 	fprintf(fp, "#define %s%s%s %s%s\n", CONFIG_, sym->name, sym_suffix,
743 		val_prefix, val);
744 
745 	free(escaped);
746 }
747 
748 /*
749  * Write out a minimal config.
750  * All values that has default values are skipped as this is redundant.
751  */
752 int conf_write_defconfig(const char *filename)
753 {
754 	struct symbol *sym;
755 	struct menu *menu;
756 	FILE *out;
757 
758 	out = fopen(filename, "w");
759 	if (!out)
760 		return 1;
761 
762 	sym_clear_all_valid();
763 
764 	/* Traverse all menus to find all relevant symbols */
765 	menu = rootmenu.list;
766 
767 	while (menu != NULL)
768 	{
769 		sym = menu->sym;
770 		if (sym == NULL) {
771 			if (!menu_is_visible(menu))
772 				goto next_menu;
773 		} else if (!sym_is_choice(sym)) {
774 			sym_calc_value(sym);
775 			if (!(sym->flags & SYMBOL_WRITE))
776 				goto next_menu;
777 			sym->flags &= ~SYMBOL_WRITE;
778 			/* If we cannot change the symbol - skip */
779 			if (!sym_is_changeable(sym))
780 				goto next_menu;
781 			/* If symbol equals to default value - skip */
782 			if (strcmp(sym_get_string_value(sym), sym_get_string_default(sym)) == 0)
783 				goto next_menu;
784 
785 			/*
786 			 * If symbol is a choice value and equals to the
787 			 * default for a choice - skip.
788 			 * But only if value is bool and equal to "y" and
789 			 * choice is not "optional".
790 			 * (If choice is "optional" then all values can be "n")
791 			 */
792 			if (sym_is_choice_value(sym)) {
793 				struct symbol *cs;
794 				struct symbol *ds;
795 
796 				cs = prop_get_symbol(sym_get_choice_prop(sym));
797 				ds = sym_choice_default(cs);
798 				if (!sym_is_optional(cs) && sym == ds) {
799 					if ((sym->type == S_BOOLEAN) &&
800 					    sym_get_tristate_value(sym) == yes)
801 						goto next_menu;
802 				}
803 			}
804 			print_symbol_for_dotconfig(out, sym);
805 		}
806 next_menu:
807 		if (menu->list != NULL) {
808 			menu = menu->list;
809 		}
810 		else if (menu->next != NULL) {
811 			menu = menu->next;
812 		} else {
813 			while ((menu = menu->parent)) {
814 				if (menu->next != NULL) {
815 					menu = menu->next;
816 					break;
817 				}
818 			}
819 		}
820 	}
821 	fclose(out);
822 	return 0;
823 }
824 
825 int conf_write(const char *name)
826 {
827 	FILE *out;
828 	struct symbol *sym;
829 	struct menu *menu;
830 	const char *str;
831 	char tmpname[PATH_MAX + 1], oldname[PATH_MAX + 1];
832 	char *env;
833 	int i;
834 	bool need_newline = false;
835 
836 	if (!name)
837 		name = conf_get_configname();
838 
839 	if (!*name) {
840 		fprintf(stderr, "config name is empty\n");
841 		return -1;
842 	}
843 
844 	if (is_dir(name)) {
845 		fprintf(stderr, "%s: Is a directory\n", name);
846 		return -1;
847 	}
848 
849 	if (make_parent_dir(name))
850 		return -1;
851 
852 	env = getenv("KCONFIG_OVERWRITECONFIG");
853 	if (env && *env) {
854 		*tmpname = 0;
855 		out = fopen(name, "w");
856 	} else {
857 		snprintf(tmpname, sizeof(tmpname), "%s.%d.tmp",
858 			 name, (int)getpid());
859 		out = fopen(tmpname, "w");
860 	}
861 	if (!out)
862 		return 1;
863 
864 	conf_write_heading(out, &comment_style_pound);
865 
866 	if (!conf_get_changed())
867 		sym_clear_all_valid();
868 
869 	menu = rootmenu.list;
870 	while (menu) {
871 		sym = menu->sym;
872 		if (!sym) {
873 			if (!menu_is_visible(menu))
874 				goto next;
875 			str = menu_get_prompt(menu);
876 			fprintf(out, "\n"
877 				     "#\n"
878 				     "# %s\n"
879 				     "#\n", str);
880 			need_newline = false;
881 		} else if (!(sym->flags & SYMBOL_CHOICE) &&
882 			   !(sym->flags & SYMBOL_WRITTEN)) {
883 			sym_calc_value(sym);
884 			if (!(sym->flags & SYMBOL_WRITE))
885 				goto next;
886 			if (need_newline) {
887 				fprintf(out, "\n");
888 				need_newline = false;
889 			}
890 			sym->flags |= SYMBOL_WRITTEN;
891 			print_symbol_for_dotconfig(out, sym);
892 		}
893 
894 next:
895 		if (menu->list) {
896 			menu = menu->list;
897 			continue;
898 		}
899 
900 end_check:
901 		if (!menu->sym && menu_is_visible(menu) && menu != &rootmenu &&
902 		    menu->prompt->type == P_MENU) {
903 			fprintf(out, "# end of %s\n", menu_get_prompt(menu));
904 			need_newline = true;
905 		}
906 
907 		if (menu->next) {
908 			menu = menu->next;
909 		} else {
910 			menu = menu->parent;
911 			if (menu)
912 				goto end_check;
913 		}
914 	}
915 	fclose(out);
916 
917 	for_all_symbols(i, sym)
918 		sym->flags &= ~SYMBOL_WRITTEN;
919 
920 	if (*tmpname) {
921 		if (is_same(name, tmpname)) {
922 			conf_message("No change to %s", name);
923 			unlink(tmpname);
924 			conf_set_changed(false);
925 			return 0;
926 		}
927 
928 		snprintf(oldname, sizeof(oldname), "%s.old", name);
929 		rename(name, oldname);
930 		if (rename(tmpname, name))
931 			return 1;
932 	}
933 
934 	conf_message("configuration written to %s", name);
935 
936 	conf_set_changed(false);
937 
938 	return 0;
939 }
940 
941 /* write a dependency file as used by kbuild to track dependencies */
942 static int conf_write_autoconf_cmd(const char *autoconf_name)
943 {
944 	char name[PATH_MAX], tmp[PATH_MAX];
945 	struct file *file;
946 	FILE *out;
947 	int ret;
948 
949 	ret = snprintf(name, sizeof(name), "%s.cmd", autoconf_name);
950 	if (ret >= sizeof(name)) /* check truncation */
951 		return -1;
952 
953 	if (make_parent_dir(name))
954 		return -1;
955 
956 	ret = snprintf(tmp, sizeof(tmp), "%s.cmd.tmp", autoconf_name);
957 	if (ret >= sizeof(tmp)) /* check truncation */
958 		return -1;
959 
960 	out = fopen(tmp, "w");
961 	if (!out) {
962 		perror("fopen");
963 		return -1;
964 	}
965 
966 	fprintf(out, "deps_config := \\\n");
967 	for (file = file_list; file; file = file->next)
968 		fprintf(out, "\t%s \\\n", file->name);
969 
970 	fprintf(out, "\n%s: $(deps_config)\n\n", autoconf_name);
971 
972 	env_write_dep(out, autoconf_name);
973 
974 	fprintf(out, "\n$(deps_config): ;\n");
975 
976 	fflush(out);
977 	ret = ferror(out); /* error check for all fprintf() calls */
978 	fclose(out);
979 	if (ret)
980 		return -1;
981 
982 	if (rename(tmp, name)) {
983 		perror("rename");
984 		return -1;
985 	}
986 
987 	return 0;
988 }
989 
990 static int conf_touch_deps(void)
991 {
992 	const char *name, *tmp;
993 	struct symbol *sym;
994 	int res, i;
995 
996 	name = conf_get_autoconfig_name();
997 	tmp = strrchr(name, '/');
998 	depfile_prefix_len = tmp ? tmp - name + 1 : 0;
999 	if (depfile_prefix_len + 1 > sizeof(depfile_path))
1000 		return -1;
1001 
1002 	strncpy(depfile_path, name, depfile_prefix_len);
1003 	depfile_path[depfile_prefix_len] = 0;
1004 
1005 	conf_read_simple(name, S_DEF_AUTO);
1006 	sym_calc_value(modules_sym);
1007 
1008 	for_all_symbols(i, sym) {
1009 		sym_calc_value(sym);
1010 		if ((sym->flags & SYMBOL_NO_WRITE) || !sym->name)
1011 			continue;
1012 		if (sym->flags & SYMBOL_WRITE) {
1013 			if (sym->flags & SYMBOL_DEF_AUTO) {
1014 				/*
1015 				 * symbol has old and new value,
1016 				 * so compare them...
1017 				 */
1018 				switch (sym->type) {
1019 				case S_BOOLEAN:
1020 				case S_TRISTATE:
1021 					if (sym_get_tristate_value(sym) ==
1022 					    sym->def[S_DEF_AUTO].tri)
1023 						continue;
1024 					break;
1025 				case S_STRING:
1026 				case S_HEX:
1027 				case S_INT:
1028 					if (!strcmp(sym_get_string_value(sym),
1029 						    sym->def[S_DEF_AUTO].val))
1030 						continue;
1031 					break;
1032 				default:
1033 					break;
1034 				}
1035 			} else {
1036 				/*
1037 				 * If there is no old value, only 'no' (unset)
1038 				 * is allowed as new value.
1039 				 */
1040 				switch (sym->type) {
1041 				case S_BOOLEAN:
1042 				case S_TRISTATE:
1043 					if (sym_get_tristate_value(sym) == no)
1044 						continue;
1045 					break;
1046 				default:
1047 					break;
1048 				}
1049 			}
1050 		} else if (!(sym->flags & SYMBOL_DEF_AUTO))
1051 			/* There is neither an old nor a new value. */
1052 			continue;
1053 		/* else
1054 		 *	There is an old value, but no new value ('no' (unset)
1055 		 *	isn't saved in auto.conf, so the old value is always
1056 		 *	different from 'no').
1057 		 */
1058 
1059 		res = conf_touch_dep(sym->name);
1060 		if (res)
1061 			return res;
1062 	}
1063 
1064 	return 0;
1065 }
1066 
1067 static int __conf_write_autoconf(const char *filename,
1068 				 void (*print_symbol)(FILE *, struct symbol *),
1069 				 const struct comment_style *comment_style)
1070 {
1071 	char tmp[PATH_MAX];
1072 	FILE *file;
1073 	struct symbol *sym;
1074 	int ret, i;
1075 
1076 	if (make_parent_dir(filename))
1077 		return -1;
1078 
1079 	ret = snprintf(tmp, sizeof(tmp), "%s.tmp", filename);
1080 	if (ret >= sizeof(tmp)) /* check truncation */
1081 		return -1;
1082 
1083 	file = fopen(tmp, "w");
1084 	if (!file) {
1085 		perror("fopen");
1086 		return -1;
1087 	}
1088 
1089 	conf_write_heading(file, comment_style);
1090 
1091 	for_all_symbols(i, sym)
1092 		if ((sym->flags & SYMBOL_WRITE) && sym->name)
1093 			print_symbol(file, sym);
1094 
1095 	fflush(file);
1096 	/* check possible errors in conf_write_heading() and print_symbol() */
1097 	ret = ferror(file);
1098 	fclose(file);
1099 	if (ret)
1100 		return -1;
1101 
1102 	if (rename(tmp, filename)) {
1103 		perror("rename");
1104 		return -1;
1105 	}
1106 
1107 	return 0;
1108 }
1109 
1110 int conf_write_autoconf(int overwrite)
1111 {
1112 	struct symbol *sym;
1113 	const char *autoconf_name = conf_get_autoconfig_name();
1114 	int ret, i;
1115 
1116 	if (!overwrite && is_present(autoconf_name))
1117 		return 0;
1118 
1119 	ret = conf_write_autoconf_cmd(autoconf_name);
1120 	if (ret)
1121 		return -1;
1122 
1123 	if (conf_touch_deps())
1124 		return 1;
1125 
1126 	for_all_symbols(i, sym)
1127 		sym_calc_value(sym);
1128 
1129 	ret = __conf_write_autoconf(conf_get_autoheader_name(),
1130 				    print_symbol_for_c,
1131 				    &comment_style_c);
1132 	if (ret)
1133 		return ret;
1134 
1135 	/*
1136 	 * Create include/config/auto.conf. This must be the last step because
1137 	 * Kbuild has a dependency on auto.conf and this marks the successful
1138 	 * completion of the previous steps.
1139 	 */
1140 	ret = __conf_write_autoconf(conf_get_autoconfig_name(),
1141 				    print_symbol_for_autoconf,
1142 				    &comment_style_pound);
1143 	if (ret)
1144 		return ret;
1145 
1146 	return 0;
1147 }
1148 
1149 static bool conf_changed;
1150 static void (*conf_changed_callback)(void);
1151 
1152 void conf_set_changed(bool val)
1153 {
1154 	if (conf_changed_callback && conf_changed != val)
1155 		conf_changed_callback();
1156 
1157 	conf_changed = val;
1158 }
1159 
1160 bool conf_get_changed(void)
1161 {
1162 	return conf_changed;
1163 }
1164 
1165 void conf_set_changed_callback(void (*fn)(void))
1166 {
1167 	conf_changed_callback = fn;
1168 }
1169 
1170 void set_all_choice_values(struct symbol *csym)
1171 {
1172 	struct property *prop;
1173 	struct symbol *sym;
1174 	struct expr *e;
1175 
1176 	prop = sym_get_choice_prop(csym);
1177 
1178 	/*
1179 	 * Set all non-assinged choice values to no
1180 	 */
1181 	expr_list_for_each_sym(prop->expr, e, sym) {
1182 		if (!sym_has_value(sym))
1183 			sym->def[S_DEF_USER].tri = no;
1184 	}
1185 	csym->flags |= SYMBOL_DEF_USER;
1186 	/* clear VALID to get value calculated */
1187 	csym->flags &= ~(SYMBOL_VALID | SYMBOL_NEED_SET_CHOICE_VALUES);
1188 }
1189