xref: /linux/scripts/kconfig/confdata.c (revision 53c5adff34d77166ed69a4e4bdae3694fe961476)
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 const char *conf_get_rustccfg_name(void)
220 {
221 	char *name = getenv("KCONFIG_RUSTCCFG");
222 
223 	return name ? name : "include/generated/rustc_cfg";
224 }
225 
226 static int conf_set_sym_val(struct symbol *sym, int def, int def_flags, char *p)
227 {
228 	char *p2;
229 
230 	switch (sym->type) {
231 	case S_TRISTATE:
232 		if (p[0] == 'm') {
233 			sym->def[def].tri = mod;
234 			sym->flags |= def_flags;
235 			break;
236 		}
237 		/* fall through */
238 	case S_BOOLEAN:
239 		if (p[0] == 'y') {
240 			sym->def[def].tri = yes;
241 			sym->flags |= def_flags;
242 			break;
243 		}
244 		if (p[0] == 'n') {
245 			sym->def[def].tri = no;
246 			sym->flags |= def_flags;
247 			break;
248 		}
249 		if (def != S_DEF_AUTO)
250 			conf_warning("symbol value '%s' invalid for %s",
251 				     p, sym->name);
252 		return 1;
253 	case S_STRING:
254 		/* No escaping for S_DEF_AUTO (include/config/auto.conf) */
255 		if (def != S_DEF_AUTO) {
256 			if (*p++ != '"')
257 				break;
258 			for (p2 = p; (p2 = strpbrk(p2, "\"\\")); p2++) {
259 				if (*p2 == '"') {
260 					*p2 = 0;
261 					break;
262 				}
263 				memmove(p2, p2 + 1, strlen(p2));
264 			}
265 			if (!p2) {
266 				conf_warning("invalid string found");
267 				return 1;
268 			}
269 		}
270 		/* fall through */
271 	case S_INT:
272 	case S_HEX:
273 		if (sym_string_valid(sym, p)) {
274 			sym->def[def].val = xstrdup(p);
275 			sym->flags |= def_flags;
276 		} else {
277 			if (def != S_DEF_AUTO)
278 				conf_warning("symbol value '%s' invalid for %s",
279 					     p, sym->name);
280 			return 1;
281 		}
282 		break;
283 	default:
284 		;
285 	}
286 	return 0;
287 }
288 
289 #define LINE_GROWTH 16
290 static int add_byte(int c, char **lineptr, size_t slen, size_t *n)
291 {
292 	size_t new_size = slen + 1;
293 
294 	if (new_size > *n) {
295 		new_size += LINE_GROWTH - 1;
296 		new_size *= 2;
297 		*lineptr = xrealloc(*lineptr, new_size);
298 		*n = new_size;
299 	}
300 
301 	(*lineptr)[slen] = c;
302 
303 	return 0;
304 }
305 
306 static ssize_t compat_getline(char **lineptr, size_t *n, FILE *stream)
307 {
308 	char *line = *lineptr;
309 	size_t slen = 0;
310 
311 	for (;;) {
312 		int c = getc(stream);
313 
314 		switch (c) {
315 		case '\n':
316 			if (add_byte(c, &line, slen, n) < 0)
317 				goto e_out;
318 			slen++;
319 			/* fall through */
320 		case EOF:
321 			if (add_byte('\0', &line, slen, n) < 0)
322 				goto e_out;
323 			*lineptr = line;
324 			if (slen == 0)
325 				return -1;
326 			return slen;
327 		default:
328 			if (add_byte(c, &line, slen, n) < 0)
329 				goto e_out;
330 			slen++;
331 		}
332 	}
333 
334 e_out:
335 	line[slen-1] = '\0';
336 	*lineptr = line;
337 	return -1;
338 }
339 
340 /* like getline(), but the newline character is stripped away */
341 static ssize_t getline_stripped(char **lineptr, size_t *n, FILE *stream)
342 {
343 	ssize_t len;
344 
345 	len = compat_getline(lineptr, n, stream);
346 
347 	if (len > 0 && (*lineptr)[len - 1] == '\n') {
348 		len--;
349 		(*lineptr)[len] = '\0';
350 
351 		if (len > 0 && (*lineptr)[len - 1] == '\r') {
352 			len--;
353 			(*lineptr)[len] = '\0';
354 		}
355 	}
356 
357 	return len;
358 }
359 
360 int conf_read_simple(const char *name, int def)
361 {
362 	FILE *in = NULL;
363 	char   *line = NULL;
364 	size_t  line_asize = 0;
365 	char *p, *val;
366 	struct symbol *sym;
367 	int i, def_flags;
368 	const char *warn_unknown, *werror, *sym_name;
369 
370 	warn_unknown = getenv("KCONFIG_WARN_UNKNOWN_SYMBOLS");
371 	werror = getenv("KCONFIG_WERROR");
372 	if (name) {
373 		in = zconf_fopen(name);
374 	} else {
375 		char *env;
376 
377 		name = conf_get_configname();
378 		in = zconf_fopen(name);
379 		if (in)
380 			goto load;
381 		conf_set_changed(true);
382 
383 		env = getenv("KCONFIG_DEFCONFIG_LIST");
384 		if (!env)
385 			return 1;
386 
387 		while (1) {
388 			bool is_last;
389 
390 			while (isspace(*env))
391 				env++;
392 
393 			if (!*env)
394 				break;
395 
396 			p = env;
397 			while (*p && !isspace(*p))
398 				p++;
399 
400 			is_last = (*p == '\0');
401 
402 			*p = '\0';
403 
404 			in = zconf_fopen(env);
405 			if (in) {
406 				conf_message("using defaults found in %s",
407 					     env);
408 				goto load;
409 			}
410 
411 			if (is_last)
412 				break;
413 
414 			env = p + 1;
415 		}
416 	}
417 	if (!in)
418 		return 1;
419 
420 load:
421 	conf_filename = name;
422 	conf_lineno = 0;
423 	conf_warnings = 0;
424 
425 	def_flags = SYMBOL_DEF << def;
426 	for_all_symbols(i, sym) {
427 		sym->flags |= SYMBOL_CHANGED;
428 		sym->flags &= ~(def_flags|SYMBOL_VALID);
429 		if (sym_is_choice(sym))
430 			sym->flags |= def_flags;
431 		switch (sym->type) {
432 		case S_INT:
433 		case S_HEX:
434 		case S_STRING:
435 			if (sym->def[def].val)
436 				free(sym->def[def].val);
437 			/* fall through */
438 		default:
439 			sym->def[def].val = NULL;
440 			sym->def[def].tri = no;
441 		}
442 	}
443 
444 	while (getline_stripped(&line, &line_asize, in) != -1) {
445 		conf_lineno++;
446 
447 		if (!line[0]) /* blank line */
448 			continue;
449 
450 		if (line[0] == '#') {
451 			if (line[1] != ' ')
452 				continue;
453 			p = line + 2;
454 			if (memcmp(p, CONFIG_, strlen(CONFIG_)))
455 				continue;
456 			sym_name = p + strlen(CONFIG_);
457 			p = strchr(sym_name, ' ');
458 			if (!p)
459 				continue;
460 			*p++ = 0;
461 			if (strcmp(p, "is not set"))
462 				continue;
463 
464 			val = "n";
465 		} else {
466 			if (memcmp(line, CONFIG_, strlen(CONFIG_))) {
467 				conf_warning("unexpected data: %s", line);
468 				continue;
469 			}
470 
471 			sym_name = line + strlen(CONFIG_);
472 			p = strchr(sym_name, '=');
473 			if (!p) {
474 				conf_warning("unexpected data: %s", line);
475 				continue;
476 			}
477 			*p = 0;
478 			val = p + 1;
479 		}
480 
481 		sym = sym_find(sym_name);
482 		if (!sym) {
483 			if (def == S_DEF_AUTO) {
484 				/*
485 				 * Reading from include/config/auto.conf.
486 				 * If CONFIG_FOO previously existed in auto.conf
487 				 * but it is missing now, include/config/FOO
488 				 * must be touched.
489 				 */
490 				conf_touch_dep(sym_name);
491 			} else {
492 				if (warn_unknown)
493 					conf_warning("unknown symbol: %s", sym_name);
494 
495 				conf_set_changed(true);
496 			}
497 			continue;
498 		}
499 
500 		if (sym->flags & def_flags)
501 			conf_warning("override: reassigning to symbol %s", sym->name);
502 
503 		if (conf_set_sym_val(sym, def, def_flags, val))
504 			continue;
505 
506 		if (sym && sym_is_choice_value(sym)) {
507 			struct symbol *cs = prop_get_symbol(sym_get_choice_prop(sym));
508 			switch (sym->def[def].tri) {
509 			case no:
510 				break;
511 			case mod:
512 				if (cs->def[def].tri == yes) {
513 					conf_warning("%s creates inconsistent choice state", sym->name);
514 					cs->flags &= ~def_flags;
515 				}
516 				break;
517 			case yes:
518 				if (cs->def[def].tri != no)
519 					conf_warning("override: %s changes choice state", sym->name);
520 				cs->def[def].val = sym;
521 				break;
522 			}
523 			cs->def[def].tri = EXPR_OR(cs->def[def].tri, sym->def[def].tri);
524 		}
525 	}
526 	free(line);
527 	fclose(in);
528 
529 	if (conf_warnings && werror)
530 		exit(1);
531 
532 	return 0;
533 }
534 
535 int conf_read(const char *name)
536 {
537 	struct symbol *sym;
538 	int conf_unsaved = 0;
539 	int i;
540 
541 	conf_set_changed(false);
542 
543 	if (conf_read_simple(name, S_DEF_USER)) {
544 		sym_calc_value(modules_sym);
545 		return 1;
546 	}
547 
548 	sym_calc_value(modules_sym);
549 
550 	for_all_symbols(i, sym) {
551 		sym_calc_value(sym);
552 		if (sym_is_choice(sym) || (sym->flags & SYMBOL_NO_WRITE))
553 			continue;
554 		if (sym_has_value(sym) && (sym->flags & SYMBOL_WRITE)) {
555 			/* check that calculated value agrees with saved value */
556 			switch (sym->type) {
557 			case S_BOOLEAN:
558 			case S_TRISTATE:
559 				if (sym->def[S_DEF_USER].tri == sym_get_tristate_value(sym))
560 					continue;
561 				break;
562 			default:
563 				if (!strcmp(sym->curr.val, sym->def[S_DEF_USER].val))
564 					continue;
565 				break;
566 			}
567 		} else if (!sym_has_value(sym) && !(sym->flags & SYMBOL_WRITE))
568 			/* no previous value and not saved */
569 			continue;
570 		conf_unsaved++;
571 		/* maybe print value in verbose mode... */
572 	}
573 
574 	for_all_symbols(i, sym) {
575 		if (sym_has_value(sym) && !sym_is_choice_value(sym)) {
576 			/* Reset values of generates values, so they'll appear
577 			 * as new, if they should become visible, but that
578 			 * doesn't quite work if the Kconfig and the saved
579 			 * configuration disagree.
580 			 */
581 			if (sym->visible == no && !conf_unsaved)
582 				sym->flags &= ~SYMBOL_DEF_USER;
583 			switch (sym->type) {
584 			case S_STRING:
585 			case S_INT:
586 			case S_HEX:
587 				/* Reset a string value if it's out of range */
588 				if (sym_string_within_range(sym, sym->def[S_DEF_USER].val))
589 					break;
590 				sym->flags &= ~SYMBOL_VALID;
591 				conf_unsaved++;
592 				break;
593 			default:
594 				break;
595 			}
596 		}
597 	}
598 
599 	if (conf_warnings || conf_unsaved)
600 		conf_set_changed(true);
601 
602 	return 0;
603 }
604 
605 struct comment_style {
606 	const char *decoration;
607 	const char *prefix;
608 	const char *postfix;
609 };
610 
611 static const struct comment_style comment_style_pound = {
612 	.decoration = "#",
613 	.prefix = "#",
614 	.postfix = "#",
615 };
616 
617 static const struct comment_style comment_style_c = {
618 	.decoration = " *",
619 	.prefix = "/*",
620 	.postfix = " */",
621 };
622 
623 static void conf_write_heading(FILE *fp, const struct comment_style *cs)
624 {
625 	if (!cs)
626 		return;
627 
628 	fprintf(fp, "%s\n", cs->prefix);
629 
630 	fprintf(fp, "%s Automatically generated file; DO NOT EDIT.\n",
631 		cs->decoration);
632 
633 	fprintf(fp, "%s %s\n", cs->decoration, rootmenu.prompt->text);
634 
635 	fprintf(fp, "%s\n", cs->postfix);
636 }
637 
638 /* The returned pointer must be freed on the caller side */
639 static char *escape_string_value(const char *in)
640 {
641 	const char *p;
642 	char *out;
643 	size_t len;
644 
645 	len = strlen(in) + strlen("\"\"") + 1;
646 
647 	p = in;
648 	while (1) {
649 		p += strcspn(p, "\"\\");
650 
651 		if (p[0] == '\0')
652 			break;
653 
654 		len++;
655 		p++;
656 	}
657 
658 	out = xmalloc(len);
659 	out[0] = '\0';
660 
661 	strcat(out, "\"");
662 
663 	p = in;
664 	while (1) {
665 		len = strcspn(p, "\"\\");
666 		strncat(out, p, len);
667 		p += len;
668 
669 		if (p[0] == '\0')
670 			break;
671 
672 		strcat(out, "\\");
673 		strncat(out, p++, 1);
674 	}
675 
676 	strcat(out, "\"");
677 
678 	return out;
679 }
680 
681 enum output_n { OUTPUT_N, OUTPUT_N_AS_UNSET, OUTPUT_N_NONE };
682 
683 static void __print_symbol(FILE *fp, struct symbol *sym, enum output_n output_n,
684 			   bool escape_string)
685 {
686 	const char *val;
687 	char *escaped = NULL;
688 
689 	if (sym->type == S_UNKNOWN)
690 		return;
691 
692 	val = sym_get_string_value(sym);
693 
694 	if ((sym->type == S_BOOLEAN || sym->type == S_TRISTATE) &&
695 	    output_n != OUTPUT_N && *val == 'n') {
696 		if (output_n == OUTPUT_N_AS_UNSET)
697 			fprintf(fp, "# %s%s is not set\n", CONFIG_, sym->name);
698 		return;
699 	}
700 
701 	if (sym->type == S_STRING && escape_string) {
702 		escaped = escape_string_value(val);
703 		val = escaped;
704 	}
705 
706 	fprintf(fp, "%s%s=%s\n", CONFIG_, sym->name, val);
707 
708 	free(escaped);
709 }
710 
711 static void print_symbol_for_dotconfig(FILE *fp, struct symbol *sym)
712 {
713 	__print_symbol(fp, sym, OUTPUT_N_AS_UNSET, true);
714 }
715 
716 static void print_symbol_for_autoconf(FILE *fp, struct symbol *sym)
717 {
718 	__print_symbol(fp, sym, OUTPUT_N_NONE, false);
719 }
720 
721 void print_symbol_for_listconfig(struct symbol *sym)
722 {
723 	__print_symbol(stdout, sym, OUTPUT_N, true);
724 }
725 
726 static void print_symbol_for_c(FILE *fp, struct symbol *sym)
727 {
728 	const char *val;
729 	const char *sym_suffix = "";
730 	const char *val_prefix = "";
731 	char *escaped = NULL;
732 
733 	if (sym->type == S_UNKNOWN)
734 		return;
735 
736 	val = sym_get_string_value(sym);
737 
738 	switch (sym->type) {
739 	case S_BOOLEAN:
740 	case S_TRISTATE:
741 		switch (*val) {
742 		case 'n':
743 			return;
744 		case 'm':
745 			sym_suffix = "_MODULE";
746 			/* fall through */
747 		default:
748 			val = "1";
749 		}
750 		break;
751 	case S_HEX:
752 		if (val[0] != '0' || (val[1] != 'x' && val[1] != 'X'))
753 			val_prefix = "0x";
754 		break;
755 	case S_STRING:
756 		escaped = escape_string_value(val);
757 		val = escaped;
758 	default:
759 		break;
760 	}
761 
762 	fprintf(fp, "#define %s%s%s %s%s\n", CONFIG_, sym->name, sym_suffix,
763 		val_prefix, val);
764 
765 	free(escaped);
766 }
767 
768 static void print_symbol_for_rustccfg(FILE *fp, struct symbol *sym)
769 {
770 	const char *val;
771 	const char *val_prefix = "";
772 	char *val_prefixed = NULL;
773 	size_t val_prefixed_len;
774 	char *escaped = NULL;
775 
776 	if (sym->type == S_UNKNOWN)
777 		return;
778 
779 	val = sym_get_string_value(sym);
780 
781 	switch (sym->type) {
782 	case S_BOOLEAN:
783 	case S_TRISTATE:
784 		/*
785 		 * We do not care about disabled ones, i.e. no need for
786 		 * what otherwise are "comments" in other printers.
787 		 */
788 		if (*val == 'n')
789 			return;
790 
791 		/*
792 		 * To have similar functionality to the C macro `IS_ENABLED()`
793 		 * we provide an empty `--cfg CONFIG_X` here in both `y`
794 		 * and `m` cases.
795 		 *
796 		 * Then, the common `fprintf()` below will also give us
797 		 * a `--cfg CONFIG_X="y"` or `--cfg CONFIG_X="m"`, which can
798 		 * be used as the equivalent of `IS_BUILTIN()`/`IS_MODULE()`.
799 		 */
800 		fprintf(fp, "--cfg=%s%s\n", CONFIG_, sym->name);
801 		break;
802 	case S_HEX:
803 		if (val[0] != '0' || (val[1] != 'x' && val[1] != 'X'))
804 			val_prefix = "0x";
805 		break;
806 	default:
807 		break;
808 	}
809 
810 	if (strlen(val_prefix) > 0) {
811 		val_prefixed_len = strlen(val) + strlen(val_prefix) + 1;
812 		val_prefixed = xmalloc(val_prefixed_len);
813 		snprintf(val_prefixed, val_prefixed_len, "%s%s", val_prefix, val);
814 		val = val_prefixed;
815 	}
816 
817 	/* All values get escaped: the `--cfg` option only takes strings */
818 	escaped = escape_string_value(val);
819 	val = escaped;
820 
821 	fprintf(fp, "--cfg=%s%s=%s\n", CONFIG_, sym->name, val);
822 
823 	free(escaped);
824 	free(val_prefixed);
825 }
826 
827 /*
828  * Write out a minimal config.
829  * All values that has default values are skipped as this is redundant.
830  */
831 int conf_write_defconfig(const char *filename)
832 {
833 	struct symbol *sym;
834 	struct menu *menu;
835 	FILE *out;
836 
837 	out = fopen(filename, "w");
838 	if (!out)
839 		return 1;
840 
841 	sym_clear_all_valid();
842 
843 	/* Traverse all menus to find all relevant symbols */
844 	menu = rootmenu.list;
845 
846 	while (menu != NULL)
847 	{
848 		sym = menu->sym;
849 		if (sym == NULL) {
850 			if (!menu_is_visible(menu))
851 				goto next_menu;
852 		} else if (!sym_is_choice(sym)) {
853 			sym_calc_value(sym);
854 			if (!(sym->flags & SYMBOL_WRITE))
855 				goto next_menu;
856 			sym->flags &= ~SYMBOL_WRITE;
857 			/* If we cannot change the symbol - skip */
858 			if (!sym_is_changeable(sym))
859 				goto next_menu;
860 			/* If symbol equals to default value - skip */
861 			if (strcmp(sym_get_string_value(sym), sym_get_string_default(sym)) == 0)
862 				goto next_menu;
863 
864 			/*
865 			 * If symbol is a choice value and equals to the
866 			 * default for a choice - skip.
867 			 * But only if value is bool and equal to "y" and
868 			 * choice is not "optional".
869 			 * (If choice is "optional" then all values can be "n")
870 			 */
871 			if (sym_is_choice_value(sym)) {
872 				struct symbol *cs;
873 				struct symbol *ds;
874 
875 				cs = prop_get_symbol(sym_get_choice_prop(sym));
876 				ds = sym_choice_default(cs);
877 				if (!sym_is_optional(cs) && sym == ds) {
878 					if ((sym->type == S_BOOLEAN) &&
879 					    sym_get_tristate_value(sym) == yes)
880 						goto next_menu;
881 				}
882 			}
883 			print_symbol_for_dotconfig(out, sym);
884 		}
885 next_menu:
886 		if (menu->list != NULL) {
887 			menu = menu->list;
888 		}
889 		else if (menu->next != NULL) {
890 			menu = menu->next;
891 		} else {
892 			while ((menu = menu->parent)) {
893 				if (menu->next != NULL) {
894 					menu = menu->next;
895 					break;
896 				}
897 			}
898 		}
899 	}
900 	fclose(out);
901 	return 0;
902 }
903 
904 int conf_write(const char *name)
905 {
906 	FILE *out;
907 	struct symbol *sym;
908 	struct menu *menu;
909 	const char *str;
910 	char tmpname[PATH_MAX + 1], oldname[PATH_MAX + 1];
911 	char *env;
912 	int i;
913 	bool need_newline = false;
914 
915 	if (!name)
916 		name = conf_get_configname();
917 
918 	if (!*name) {
919 		fprintf(stderr, "config name is empty\n");
920 		return -1;
921 	}
922 
923 	if (is_dir(name)) {
924 		fprintf(stderr, "%s: Is a directory\n", name);
925 		return -1;
926 	}
927 
928 	if (make_parent_dir(name))
929 		return -1;
930 
931 	env = getenv("KCONFIG_OVERWRITECONFIG");
932 	if (env && *env) {
933 		*tmpname = 0;
934 		out = fopen(name, "w");
935 	} else {
936 		snprintf(tmpname, sizeof(tmpname), "%s.%d.tmp",
937 			 name, (int)getpid());
938 		out = fopen(tmpname, "w");
939 	}
940 	if (!out)
941 		return 1;
942 
943 	conf_write_heading(out, &comment_style_pound);
944 
945 	if (!conf_get_changed())
946 		sym_clear_all_valid();
947 
948 	menu = rootmenu.list;
949 	while (menu) {
950 		sym = menu->sym;
951 		if (!sym) {
952 			if (!menu_is_visible(menu))
953 				goto next;
954 			str = menu_get_prompt(menu);
955 			fprintf(out, "\n"
956 				     "#\n"
957 				     "# %s\n"
958 				     "#\n", str);
959 			need_newline = false;
960 		} else if (!(sym->flags & SYMBOL_CHOICE) &&
961 			   !(sym->flags & SYMBOL_WRITTEN)) {
962 			sym_calc_value(sym);
963 			if (!(sym->flags & SYMBOL_WRITE))
964 				goto next;
965 			if (need_newline) {
966 				fprintf(out, "\n");
967 				need_newline = false;
968 			}
969 			sym->flags |= SYMBOL_WRITTEN;
970 			print_symbol_for_dotconfig(out, sym);
971 		}
972 
973 next:
974 		if (menu->list) {
975 			menu = menu->list;
976 			continue;
977 		}
978 
979 end_check:
980 		if (!menu->sym && menu_is_visible(menu) && menu != &rootmenu &&
981 		    menu->prompt->type == P_MENU) {
982 			fprintf(out, "# end of %s\n", menu_get_prompt(menu));
983 			need_newline = true;
984 		}
985 
986 		if (menu->next) {
987 			menu = menu->next;
988 		} else {
989 			menu = menu->parent;
990 			if (menu)
991 				goto end_check;
992 		}
993 	}
994 	fclose(out);
995 
996 	for_all_symbols(i, sym)
997 		sym->flags &= ~SYMBOL_WRITTEN;
998 
999 	if (*tmpname) {
1000 		if (is_same(name, tmpname)) {
1001 			conf_message("No change to %s", name);
1002 			unlink(tmpname);
1003 			conf_set_changed(false);
1004 			return 0;
1005 		}
1006 
1007 		snprintf(oldname, sizeof(oldname), "%s.old", name);
1008 		rename(name, oldname);
1009 		if (rename(tmpname, name))
1010 			return 1;
1011 	}
1012 
1013 	conf_message("configuration written to %s", name);
1014 
1015 	conf_set_changed(false);
1016 
1017 	return 0;
1018 }
1019 
1020 /* write a dependency file as used by kbuild to track dependencies */
1021 static int conf_write_autoconf_cmd(const char *autoconf_name)
1022 {
1023 	char name[PATH_MAX], tmp[PATH_MAX];
1024 	struct file *file;
1025 	FILE *out;
1026 	int ret;
1027 
1028 	ret = snprintf(name, sizeof(name), "%s.cmd", autoconf_name);
1029 	if (ret >= sizeof(name)) /* check truncation */
1030 		return -1;
1031 
1032 	if (make_parent_dir(name))
1033 		return -1;
1034 
1035 	ret = snprintf(tmp, sizeof(tmp), "%s.cmd.tmp", autoconf_name);
1036 	if (ret >= sizeof(tmp)) /* check truncation */
1037 		return -1;
1038 
1039 	out = fopen(tmp, "w");
1040 	if (!out) {
1041 		perror("fopen");
1042 		return -1;
1043 	}
1044 
1045 	fprintf(out, "deps_config := \\\n");
1046 	for (file = file_list; file; file = file->next)
1047 		fprintf(out, "\t%s \\\n", file->name);
1048 
1049 	fprintf(out, "\n%s: $(deps_config)\n\n", autoconf_name);
1050 
1051 	env_write_dep(out, autoconf_name);
1052 
1053 	fprintf(out, "\n$(deps_config): ;\n");
1054 
1055 	fflush(out);
1056 	ret = ferror(out); /* error check for all fprintf() calls */
1057 	fclose(out);
1058 	if (ret)
1059 		return -1;
1060 
1061 	if (rename(tmp, name)) {
1062 		perror("rename");
1063 		return -1;
1064 	}
1065 
1066 	return 0;
1067 }
1068 
1069 static int conf_touch_deps(void)
1070 {
1071 	const char *name, *tmp;
1072 	struct symbol *sym;
1073 	int res, i;
1074 
1075 	name = conf_get_autoconfig_name();
1076 	tmp = strrchr(name, '/');
1077 	depfile_prefix_len = tmp ? tmp - name + 1 : 0;
1078 	if (depfile_prefix_len + 1 > sizeof(depfile_path))
1079 		return -1;
1080 
1081 	strncpy(depfile_path, name, depfile_prefix_len);
1082 	depfile_path[depfile_prefix_len] = 0;
1083 
1084 	conf_read_simple(name, S_DEF_AUTO);
1085 	sym_calc_value(modules_sym);
1086 
1087 	for_all_symbols(i, sym) {
1088 		sym_calc_value(sym);
1089 		if ((sym->flags & SYMBOL_NO_WRITE) || !sym->name)
1090 			continue;
1091 		if (sym->flags & SYMBOL_WRITE) {
1092 			if (sym->flags & SYMBOL_DEF_AUTO) {
1093 				/*
1094 				 * symbol has old and new value,
1095 				 * so compare them...
1096 				 */
1097 				switch (sym->type) {
1098 				case S_BOOLEAN:
1099 				case S_TRISTATE:
1100 					if (sym_get_tristate_value(sym) ==
1101 					    sym->def[S_DEF_AUTO].tri)
1102 						continue;
1103 					break;
1104 				case S_STRING:
1105 				case S_HEX:
1106 				case S_INT:
1107 					if (!strcmp(sym_get_string_value(sym),
1108 						    sym->def[S_DEF_AUTO].val))
1109 						continue;
1110 					break;
1111 				default:
1112 					break;
1113 				}
1114 			} else {
1115 				/*
1116 				 * If there is no old value, only 'no' (unset)
1117 				 * is allowed as new value.
1118 				 */
1119 				switch (sym->type) {
1120 				case S_BOOLEAN:
1121 				case S_TRISTATE:
1122 					if (sym_get_tristate_value(sym) == no)
1123 						continue;
1124 					break;
1125 				default:
1126 					break;
1127 				}
1128 			}
1129 		} else if (!(sym->flags & SYMBOL_DEF_AUTO))
1130 			/* There is neither an old nor a new value. */
1131 			continue;
1132 		/* else
1133 		 *	There is an old value, but no new value ('no' (unset)
1134 		 *	isn't saved in auto.conf, so the old value is always
1135 		 *	different from 'no').
1136 		 */
1137 
1138 		res = conf_touch_dep(sym->name);
1139 		if (res)
1140 			return res;
1141 	}
1142 
1143 	return 0;
1144 }
1145 
1146 static int __conf_write_autoconf(const char *filename,
1147 				 void (*print_symbol)(FILE *, struct symbol *),
1148 				 const struct comment_style *comment_style)
1149 {
1150 	char tmp[PATH_MAX];
1151 	FILE *file;
1152 	struct symbol *sym;
1153 	int ret, i;
1154 
1155 	if (make_parent_dir(filename))
1156 		return -1;
1157 
1158 	ret = snprintf(tmp, sizeof(tmp), "%s.tmp", filename);
1159 	if (ret >= sizeof(tmp)) /* check truncation */
1160 		return -1;
1161 
1162 	file = fopen(tmp, "w");
1163 	if (!file) {
1164 		perror("fopen");
1165 		return -1;
1166 	}
1167 
1168 	conf_write_heading(file, comment_style);
1169 
1170 	for_all_symbols(i, sym)
1171 		if ((sym->flags & SYMBOL_WRITE) && sym->name)
1172 			print_symbol(file, sym);
1173 
1174 	fflush(file);
1175 	/* check possible errors in conf_write_heading() and print_symbol() */
1176 	ret = ferror(file);
1177 	fclose(file);
1178 	if (ret)
1179 		return -1;
1180 
1181 	if (rename(tmp, filename)) {
1182 		perror("rename");
1183 		return -1;
1184 	}
1185 
1186 	return 0;
1187 }
1188 
1189 int conf_write_autoconf(int overwrite)
1190 {
1191 	struct symbol *sym;
1192 	const char *autoconf_name = conf_get_autoconfig_name();
1193 	int ret, i;
1194 
1195 	if (!overwrite && is_present(autoconf_name))
1196 		return 0;
1197 
1198 	ret = conf_write_autoconf_cmd(autoconf_name);
1199 	if (ret)
1200 		return -1;
1201 
1202 	if (conf_touch_deps())
1203 		return 1;
1204 
1205 	for_all_symbols(i, sym)
1206 		sym_calc_value(sym);
1207 
1208 	ret = __conf_write_autoconf(conf_get_autoheader_name(),
1209 				    print_symbol_for_c,
1210 				    &comment_style_c);
1211 	if (ret)
1212 		return ret;
1213 
1214 	ret = __conf_write_autoconf(conf_get_rustccfg_name(),
1215 				    print_symbol_for_rustccfg,
1216 				    NULL);
1217 	if (ret)
1218 		return ret;
1219 
1220 	/*
1221 	 * Create include/config/auto.conf. This must be the last step because
1222 	 * Kbuild has a dependency on auto.conf and this marks the successful
1223 	 * completion of the previous steps.
1224 	 */
1225 	ret = __conf_write_autoconf(conf_get_autoconfig_name(),
1226 				    print_symbol_for_autoconf,
1227 				    &comment_style_pound);
1228 	if (ret)
1229 		return ret;
1230 
1231 	return 0;
1232 }
1233 
1234 static bool conf_changed;
1235 static void (*conf_changed_callback)(void);
1236 
1237 void conf_set_changed(bool val)
1238 {
1239 	bool changed = conf_changed != val;
1240 
1241 	conf_changed = val;
1242 
1243 	if (conf_changed_callback && changed)
1244 		conf_changed_callback();
1245 }
1246 
1247 bool conf_get_changed(void)
1248 {
1249 	return conf_changed;
1250 }
1251 
1252 void conf_set_changed_callback(void (*fn)(void))
1253 {
1254 	conf_changed_callback = fn;
1255 }
1256 
1257 void set_all_choice_values(struct symbol *csym)
1258 {
1259 	struct property *prop;
1260 	struct symbol *sym;
1261 	struct expr *e;
1262 
1263 	prop = sym_get_choice_prop(csym);
1264 
1265 	/*
1266 	 * Set all non-assinged choice values to no
1267 	 */
1268 	expr_list_for_each_sym(prop->expr, e, sym) {
1269 		if (!sym_has_value(sym))
1270 			sym->def[S_DEF_USER].tri = no;
1271 	}
1272 	csym->flags |= SYMBOL_DEF_USER;
1273 	/* clear VALID to get value calculated */
1274 	csym->flags &= ~(SYMBOL_VALID | SYMBOL_NEED_SET_CHOICE_VALUES);
1275 }
1276