xref: /linux/scripts/kconfig/confdata.c (revision 90d32e92011eaae8e70a9169b4e7acf4ca8f9d3a)
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 "internal.h"
22 #include "lkc.h"
23 
24 struct gstr autoconf_cmd;
25 
26 /* return true if 'path' exists, false otherwise */
27 static bool is_present(const char *path)
28 {
29 	struct stat st;
30 
31 	return !stat(path, &st);
32 }
33 
34 /* return true if 'path' exists and it is a directory, false otherwise */
35 static bool is_dir(const char *path)
36 {
37 	struct stat st;
38 
39 	if (stat(path, &st))
40 		return false;
41 
42 	return S_ISDIR(st.st_mode);
43 }
44 
45 /* return true if the given two files are the same, false otherwise */
46 static bool is_same(const char *file1, const char *file2)
47 {
48 	int fd1, fd2;
49 	struct stat st1, st2;
50 	void *map1, *map2;
51 	bool ret = false;
52 
53 	fd1 = open(file1, O_RDONLY);
54 	if (fd1 < 0)
55 		return ret;
56 
57 	fd2 = open(file2, O_RDONLY);
58 	if (fd2 < 0)
59 		goto close1;
60 
61 	ret = fstat(fd1, &st1);
62 	if (ret)
63 		goto close2;
64 	ret = fstat(fd2, &st2);
65 	if (ret)
66 		goto close2;
67 
68 	if (st1.st_size != st2.st_size)
69 		goto close2;
70 
71 	map1 = mmap(NULL, st1.st_size, PROT_READ, MAP_PRIVATE, fd1, 0);
72 	if (map1 == MAP_FAILED)
73 		goto close2;
74 
75 	map2 = mmap(NULL, st2.st_size, PROT_READ, MAP_PRIVATE, fd2, 0);
76 	if (map2 == MAP_FAILED)
77 		goto close2;
78 
79 	if (bcmp(map1, map2, st1.st_size))
80 		goto close2;
81 
82 	ret = true;
83 close2:
84 	close(fd2);
85 close1:
86 	close(fd1);
87 
88 	return ret;
89 }
90 
91 /*
92  * Create the parent directory of the given path.
93  *
94  * For example, if 'include/config/auto.conf' is given, create 'include/config'.
95  */
96 static int make_parent_dir(const char *path)
97 {
98 	char tmp[PATH_MAX + 1];
99 	char *p;
100 
101 	strncpy(tmp, path, sizeof(tmp));
102 	tmp[sizeof(tmp) - 1] = 0;
103 
104 	/* Remove the base name. Just return if nothing is left */
105 	p = strrchr(tmp, '/');
106 	if (!p)
107 		return 0;
108 	*(p + 1) = 0;
109 
110 	/* Just in case it is an absolute path */
111 	p = tmp;
112 	while (*p == '/')
113 		p++;
114 
115 	while ((p = strchr(p, '/'))) {
116 		*p = 0;
117 
118 		/* skip if the directory exists */
119 		if (!is_dir(tmp) && mkdir(tmp, 0755))
120 			return -1;
121 
122 		*p = '/';
123 		while (*p == '/')
124 			p++;
125 	}
126 
127 	return 0;
128 }
129 
130 static char depfile_path[PATH_MAX];
131 static size_t depfile_prefix_len;
132 
133 /* touch depfile for symbol 'name' */
134 static int conf_touch_dep(const char *name)
135 {
136 	int fd;
137 
138 	/* check overflow: prefix + name + '\0' must fit in buffer. */
139 	if (depfile_prefix_len + strlen(name) + 1 > sizeof(depfile_path))
140 		return -1;
141 
142 	strcpy(depfile_path + depfile_prefix_len, name);
143 
144 	fd = open(depfile_path, O_WRONLY | O_CREAT | O_TRUNC, 0644);
145 	if (fd == -1)
146 		return -1;
147 	close(fd);
148 
149 	return 0;
150 }
151 
152 static void conf_warning(const char *fmt, ...)
153 	__attribute__ ((format (printf, 1, 2)));
154 
155 static void conf_message(const char *fmt, ...)
156 	__attribute__ ((format (printf, 1, 2)));
157 
158 static const char *conf_filename;
159 static int conf_lineno, conf_warnings;
160 
161 bool conf_errors(void)
162 {
163 	if (conf_warnings)
164 		return getenv("KCONFIG_WERROR");
165 	return false;
166 }
167 
168 static void conf_warning(const char *fmt, ...)
169 {
170 	va_list ap;
171 	va_start(ap, fmt);
172 	fprintf(stderr, "%s:%d:warning: ", conf_filename, conf_lineno);
173 	vfprintf(stderr, fmt, ap);
174 	fprintf(stderr, "\n");
175 	va_end(ap);
176 	conf_warnings++;
177 }
178 
179 static void conf_default_message_callback(const char *s)
180 {
181 	printf("#\n# ");
182 	printf("%s", s);
183 	printf("\n#\n");
184 }
185 
186 static void (*conf_message_callback)(const char *s) =
187 	conf_default_message_callback;
188 void conf_set_message_callback(void (*fn)(const char *s))
189 {
190 	conf_message_callback = fn;
191 }
192 
193 static void conf_message(const char *fmt, ...)
194 {
195 	va_list ap;
196 	char buf[4096];
197 
198 	if (!conf_message_callback)
199 		return;
200 
201 	va_start(ap, fmt);
202 
203 	vsnprintf(buf, sizeof(buf), fmt, ap);
204 	conf_message_callback(buf);
205 	va_end(ap);
206 }
207 
208 const char *conf_get_configname(void)
209 {
210 	char *name = getenv("KCONFIG_CONFIG");
211 
212 	return name ? name : ".config";
213 }
214 
215 static const char *conf_get_autoconfig_name(void)
216 {
217 	char *name = getenv("KCONFIG_AUTOCONFIG");
218 
219 	return name ? name : "include/config/auto.conf";
220 }
221 
222 static const char *conf_get_autoheader_name(void)
223 {
224 	char *name = getenv("KCONFIG_AUTOHEADER");
225 
226 	return name ? name : "include/generated/autoconf.h";
227 }
228 
229 static const char *conf_get_rustccfg_name(void)
230 {
231 	char *name = getenv("KCONFIG_RUSTCCFG");
232 
233 	return name ? name : "include/generated/rustc_cfg";
234 }
235 
236 static int conf_set_sym_val(struct symbol *sym, int def, int def_flags, char *p)
237 {
238 	char *p2;
239 
240 	switch (sym->type) {
241 	case S_TRISTATE:
242 		if (p[0] == 'm') {
243 			sym->def[def].tri = mod;
244 			sym->flags |= def_flags;
245 			break;
246 		}
247 		/* fall through */
248 	case S_BOOLEAN:
249 		if (p[0] == 'y') {
250 			sym->def[def].tri = yes;
251 			sym->flags |= def_flags;
252 			break;
253 		}
254 		if (p[0] == 'n') {
255 			sym->def[def].tri = no;
256 			sym->flags |= def_flags;
257 			break;
258 		}
259 		if (def != S_DEF_AUTO)
260 			conf_warning("symbol value '%s' invalid for %s",
261 				     p, sym->name);
262 		return 1;
263 	case S_STRING:
264 		/* No escaping for S_DEF_AUTO (include/config/auto.conf) */
265 		if (def != S_DEF_AUTO) {
266 			if (*p++ != '"')
267 				break;
268 			for (p2 = p; (p2 = strpbrk(p2, "\"\\")); p2++) {
269 				if (*p2 == '"') {
270 					*p2 = 0;
271 					break;
272 				}
273 				memmove(p2, p2 + 1, strlen(p2));
274 			}
275 			if (!p2) {
276 				conf_warning("invalid string found");
277 				return 1;
278 			}
279 		}
280 		/* fall through */
281 	case S_INT:
282 	case S_HEX:
283 		if (sym_string_valid(sym, p)) {
284 			sym->def[def].val = xstrdup(p);
285 			sym->flags |= def_flags;
286 		} else {
287 			if (def != S_DEF_AUTO)
288 				conf_warning("symbol value '%s' invalid for %s",
289 					     p, sym->name);
290 			return 1;
291 		}
292 		break;
293 	default:
294 		;
295 	}
296 	return 0;
297 }
298 
299 /* like getline(), but the newline character is stripped away */
300 static ssize_t getline_stripped(char **lineptr, size_t *n, FILE *stream)
301 {
302 	ssize_t len;
303 
304 	len = getline(lineptr, n, stream);
305 
306 	if (len > 0 && (*lineptr)[len - 1] == '\n') {
307 		len--;
308 		(*lineptr)[len] = '\0';
309 
310 		if (len > 0 && (*lineptr)[len - 1] == '\r') {
311 			len--;
312 			(*lineptr)[len] = '\0';
313 		}
314 	}
315 
316 	return len;
317 }
318 
319 int conf_read_simple(const char *name, int def)
320 {
321 	FILE *in = NULL;
322 	char   *line = NULL;
323 	size_t  line_asize = 0;
324 	char *p, *val;
325 	struct symbol *sym;
326 	int def_flags;
327 	const char *warn_unknown, *sym_name;
328 
329 	warn_unknown = getenv("KCONFIG_WARN_UNKNOWN_SYMBOLS");
330 	if (name) {
331 		in = zconf_fopen(name);
332 	} else {
333 		char *env;
334 
335 		name = conf_get_configname();
336 		in = zconf_fopen(name);
337 		if (in)
338 			goto load;
339 		conf_set_changed(true);
340 
341 		env = getenv("KCONFIG_DEFCONFIG_LIST");
342 		if (!env)
343 			return 1;
344 
345 		while (1) {
346 			bool is_last;
347 
348 			while (isspace(*env))
349 				env++;
350 
351 			if (!*env)
352 				break;
353 
354 			p = env;
355 			while (*p && !isspace(*p))
356 				p++;
357 
358 			is_last = (*p == '\0');
359 
360 			*p = '\0';
361 
362 			in = zconf_fopen(env);
363 			if (in) {
364 				conf_message("using defaults found in %s",
365 					     env);
366 				goto load;
367 			}
368 
369 			if (is_last)
370 				break;
371 
372 			env = p + 1;
373 		}
374 	}
375 	if (!in)
376 		return 1;
377 
378 load:
379 	conf_filename = name;
380 	conf_lineno = 0;
381 	conf_warnings = 0;
382 
383 	def_flags = SYMBOL_DEF << def;
384 	for_all_symbols(sym) {
385 		sym->flags |= SYMBOL_CHANGED;
386 		sym->flags &= ~(def_flags|SYMBOL_VALID);
387 		if (sym_is_choice(sym))
388 			sym->flags |= def_flags;
389 		switch (sym->type) {
390 		case S_INT:
391 		case S_HEX:
392 		case S_STRING:
393 			free(sym->def[def].val);
394 			/* fall through */
395 		default:
396 			sym->def[def].val = NULL;
397 			sym->def[def].tri = no;
398 		}
399 	}
400 
401 	while (getline_stripped(&line, &line_asize, in) != -1) {
402 		conf_lineno++;
403 
404 		if (!line[0]) /* blank line */
405 			continue;
406 
407 		if (line[0] == '#') {
408 			if (line[1] != ' ')
409 				continue;
410 			p = line + 2;
411 			if (memcmp(p, CONFIG_, strlen(CONFIG_)))
412 				continue;
413 			sym_name = p + strlen(CONFIG_);
414 			p = strchr(sym_name, ' ');
415 			if (!p)
416 				continue;
417 			*p++ = 0;
418 			if (strcmp(p, "is not set"))
419 				continue;
420 
421 			val = "n";
422 		} else {
423 			if (memcmp(line, CONFIG_, strlen(CONFIG_))) {
424 				conf_warning("unexpected data: %s", line);
425 				continue;
426 			}
427 
428 			sym_name = line + strlen(CONFIG_);
429 			p = strchr(sym_name, '=');
430 			if (!p) {
431 				conf_warning("unexpected data: %s", line);
432 				continue;
433 			}
434 			*p = 0;
435 			val = p + 1;
436 		}
437 
438 		sym = sym_find(sym_name);
439 		if (!sym) {
440 			if (def == S_DEF_AUTO) {
441 				/*
442 				 * Reading from include/config/auto.conf.
443 				 * If CONFIG_FOO previously existed in auto.conf
444 				 * but it is missing now, include/config/FOO
445 				 * must be touched.
446 				 */
447 				conf_touch_dep(sym_name);
448 			} else {
449 				if (warn_unknown)
450 					conf_warning("unknown symbol: %s", sym_name);
451 
452 				conf_set_changed(true);
453 			}
454 			continue;
455 		}
456 
457 		if (sym->flags & def_flags)
458 			conf_warning("override: reassigning to symbol %s", sym->name);
459 
460 		if (conf_set_sym_val(sym, def, def_flags, val))
461 			continue;
462 
463 		if (sym && sym_is_choice_value(sym)) {
464 			struct symbol *cs = prop_get_symbol(sym_get_choice_prop(sym));
465 			switch (sym->def[def].tri) {
466 			case no:
467 				break;
468 			case mod:
469 				if (cs->def[def].tri == yes) {
470 					conf_warning("%s creates inconsistent choice state", sym->name);
471 					cs->flags &= ~def_flags;
472 				}
473 				break;
474 			case yes:
475 				if (cs->def[def].tri != no)
476 					conf_warning("override: %s changes choice state", sym->name);
477 				cs->def[def].val = sym;
478 				break;
479 			}
480 			cs->def[def].tri = EXPR_OR(cs->def[def].tri, sym->def[def].tri);
481 		}
482 	}
483 	free(line);
484 	fclose(in);
485 
486 	return 0;
487 }
488 
489 int conf_read(const char *name)
490 {
491 	struct symbol *sym;
492 	int conf_unsaved = 0;
493 
494 	conf_set_changed(false);
495 
496 	if (conf_read_simple(name, S_DEF_USER)) {
497 		sym_calc_value(modules_sym);
498 		return 1;
499 	}
500 
501 	sym_calc_value(modules_sym);
502 
503 	for_all_symbols(sym) {
504 		sym_calc_value(sym);
505 		if (sym_is_choice(sym))
506 			continue;
507 		if (sym_has_value(sym) && (sym->flags & SYMBOL_WRITE)) {
508 			/* check that calculated value agrees with saved value */
509 			switch (sym->type) {
510 			case S_BOOLEAN:
511 			case S_TRISTATE:
512 				if (sym->def[S_DEF_USER].tri == sym_get_tristate_value(sym))
513 					continue;
514 				break;
515 			default:
516 				if (!strcmp(sym->curr.val, sym->def[S_DEF_USER].val))
517 					continue;
518 				break;
519 			}
520 		} else if (!sym_has_value(sym) && !(sym->flags & SYMBOL_WRITE))
521 			/* no previous value and not saved */
522 			continue;
523 		conf_unsaved++;
524 		/* maybe print value in verbose mode... */
525 	}
526 
527 	for_all_symbols(sym) {
528 		if (sym_has_value(sym) && !sym_is_choice_value(sym)) {
529 			/* Reset values of generates values, so they'll appear
530 			 * as new, if they should become visible, but that
531 			 * doesn't quite work if the Kconfig and the saved
532 			 * configuration disagree.
533 			 */
534 			if (sym->visible == no && !conf_unsaved)
535 				sym->flags &= ~SYMBOL_DEF_USER;
536 			switch (sym->type) {
537 			case S_STRING:
538 			case S_INT:
539 			case S_HEX:
540 				/* Reset a string value if it's out of range */
541 				if (sym_string_within_range(sym, sym->def[S_DEF_USER].val))
542 					break;
543 				sym->flags &= ~SYMBOL_VALID;
544 				conf_unsaved++;
545 				break;
546 			default:
547 				break;
548 			}
549 		}
550 	}
551 
552 	if (conf_warnings || conf_unsaved)
553 		conf_set_changed(true);
554 
555 	return 0;
556 }
557 
558 struct comment_style {
559 	const char *decoration;
560 	const char *prefix;
561 	const char *postfix;
562 };
563 
564 static const struct comment_style comment_style_pound = {
565 	.decoration = "#",
566 	.prefix = "#",
567 	.postfix = "#",
568 };
569 
570 static const struct comment_style comment_style_c = {
571 	.decoration = " *",
572 	.prefix = "/*",
573 	.postfix = " */",
574 };
575 
576 static void conf_write_heading(FILE *fp, const struct comment_style *cs)
577 {
578 	if (!cs)
579 		return;
580 
581 	fprintf(fp, "%s\n", cs->prefix);
582 
583 	fprintf(fp, "%s Automatically generated file; DO NOT EDIT.\n",
584 		cs->decoration);
585 
586 	fprintf(fp, "%s %s\n", cs->decoration, rootmenu.prompt->text);
587 
588 	fprintf(fp, "%s\n", cs->postfix);
589 }
590 
591 /* The returned pointer must be freed on the caller side */
592 static char *escape_string_value(const char *in)
593 {
594 	const char *p;
595 	char *out;
596 	size_t len;
597 
598 	len = strlen(in) + strlen("\"\"") + 1;
599 
600 	p = in;
601 	while (1) {
602 		p += strcspn(p, "\"\\");
603 
604 		if (p[0] == '\0')
605 			break;
606 
607 		len++;
608 		p++;
609 	}
610 
611 	out = xmalloc(len);
612 	out[0] = '\0';
613 
614 	strcat(out, "\"");
615 
616 	p = in;
617 	while (1) {
618 		len = strcspn(p, "\"\\");
619 		strncat(out, p, len);
620 		p += len;
621 
622 		if (p[0] == '\0')
623 			break;
624 
625 		strcat(out, "\\");
626 		strncat(out, p++, 1);
627 	}
628 
629 	strcat(out, "\"");
630 
631 	return out;
632 }
633 
634 enum output_n { OUTPUT_N, OUTPUT_N_AS_UNSET, OUTPUT_N_NONE };
635 
636 static void __print_symbol(FILE *fp, struct symbol *sym, enum output_n output_n,
637 			   bool escape_string)
638 {
639 	const char *val;
640 	char *escaped = NULL;
641 
642 	if (sym->type == S_UNKNOWN)
643 		return;
644 
645 	val = sym_get_string_value(sym);
646 
647 	if ((sym->type == S_BOOLEAN || sym->type == S_TRISTATE) &&
648 	    output_n != OUTPUT_N && *val == 'n') {
649 		if (output_n == OUTPUT_N_AS_UNSET)
650 			fprintf(fp, "# %s%s is not set\n", CONFIG_, sym->name);
651 		return;
652 	}
653 
654 	if (sym->type == S_STRING && escape_string) {
655 		escaped = escape_string_value(val);
656 		val = escaped;
657 	}
658 
659 	fprintf(fp, "%s%s=%s\n", CONFIG_, sym->name, val);
660 
661 	free(escaped);
662 }
663 
664 static void print_symbol_for_dotconfig(FILE *fp, struct symbol *sym)
665 {
666 	__print_symbol(fp, sym, OUTPUT_N_AS_UNSET, true);
667 }
668 
669 static void print_symbol_for_autoconf(FILE *fp, struct symbol *sym)
670 {
671 	__print_symbol(fp, sym, OUTPUT_N_NONE, false);
672 }
673 
674 void print_symbol_for_listconfig(struct symbol *sym)
675 {
676 	__print_symbol(stdout, sym, OUTPUT_N, true);
677 }
678 
679 static void print_symbol_for_c(FILE *fp, struct symbol *sym)
680 {
681 	const char *val;
682 	const char *sym_suffix = "";
683 	const char *val_prefix = "";
684 	char *escaped = NULL;
685 
686 	if (sym->type == S_UNKNOWN)
687 		return;
688 
689 	val = sym_get_string_value(sym);
690 
691 	switch (sym->type) {
692 	case S_BOOLEAN:
693 	case S_TRISTATE:
694 		switch (*val) {
695 		case 'n':
696 			return;
697 		case 'm':
698 			sym_suffix = "_MODULE";
699 			/* fall through */
700 		default:
701 			val = "1";
702 		}
703 		break;
704 	case S_HEX:
705 		if (val[0] != '0' || (val[1] != 'x' && val[1] != 'X'))
706 			val_prefix = "0x";
707 		break;
708 	case S_STRING:
709 		escaped = escape_string_value(val);
710 		val = escaped;
711 	default:
712 		break;
713 	}
714 
715 	fprintf(fp, "#define %s%s%s %s%s\n", CONFIG_, sym->name, sym_suffix,
716 		val_prefix, val);
717 
718 	free(escaped);
719 }
720 
721 static void print_symbol_for_rustccfg(FILE *fp, struct symbol *sym)
722 {
723 	const char *val;
724 	const char *val_prefix = "";
725 	char *val_prefixed = NULL;
726 	size_t val_prefixed_len;
727 	char *escaped = NULL;
728 
729 	if (sym->type == S_UNKNOWN)
730 		return;
731 
732 	val = sym_get_string_value(sym);
733 
734 	switch (sym->type) {
735 	case S_BOOLEAN:
736 	case S_TRISTATE:
737 		/*
738 		 * We do not care about disabled ones, i.e. no need for
739 		 * what otherwise are "comments" in other printers.
740 		 */
741 		if (*val == 'n')
742 			return;
743 
744 		/*
745 		 * To have similar functionality to the C macro `IS_ENABLED()`
746 		 * we provide an empty `--cfg CONFIG_X` here in both `y`
747 		 * and `m` cases.
748 		 *
749 		 * Then, the common `fprintf()` below will also give us
750 		 * a `--cfg CONFIG_X="y"` or `--cfg CONFIG_X="m"`, which can
751 		 * be used as the equivalent of `IS_BUILTIN()`/`IS_MODULE()`.
752 		 */
753 		fprintf(fp, "--cfg=%s%s\n", CONFIG_, sym->name);
754 		break;
755 	case S_HEX:
756 		if (val[0] != '0' || (val[1] != 'x' && val[1] != 'X'))
757 			val_prefix = "0x";
758 		break;
759 	default:
760 		break;
761 	}
762 
763 	if (strlen(val_prefix) > 0) {
764 		val_prefixed_len = strlen(val) + strlen(val_prefix) + 1;
765 		val_prefixed = xmalloc(val_prefixed_len);
766 		snprintf(val_prefixed, val_prefixed_len, "%s%s", val_prefix, val);
767 		val = val_prefixed;
768 	}
769 
770 	/* All values get escaped: the `--cfg` option only takes strings */
771 	escaped = escape_string_value(val);
772 	val = escaped;
773 
774 	fprintf(fp, "--cfg=%s%s=%s\n", CONFIG_, sym->name, val);
775 
776 	free(escaped);
777 	free(val_prefixed);
778 }
779 
780 /*
781  * Write out a minimal config.
782  * All values that has default values are skipped as this is redundant.
783  */
784 int conf_write_defconfig(const char *filename)
785 {
786 	struct symbol *sym;
787 	struct menu *menu;
788 	FILE *out;
789 
790 	out = fopen(filename, "w");
791 	if (!out)
792 		return 1;
793 
794 	sym_clear_all_valid();
795 
796 	menu_for_each_entry(menu) {
797 		struct menu *choice;
798 
799 		sym = menu->sym;
800 		if (sym && !sym_is_choice(sym)) {
801 			sym_calc_value(sym);
802 			if (!(sym->flags & SYMBOL_WRITE))
803 				continue;
804 			sym->flags &= ~SYMBOL_WRITE;
805 			/* If we cannot change the symbol - skip */
806 			if (!sym_is_changeable(sym))
807 				continue;
808 			/* If symbol equals to default value - skip */
809 			if (strcmp(sym_get_string_value(sym), sym_get_string_default(sym)) == 0)
810 				continue;
811 
812 			/*
813 			 * If symbol is a choice value and equals to the
814 			 * default for a choice - skip.
815 			 */
816 			choice = sym_get_choice_menu(sym);
817 			if (choice) {
818 				struct symbol *ds;
819 
820 				ds = sym_choice_default(choice->sym);
821 				if (sym == ds) {
822 					if ((sym->type == S_BOOLEAN) &&
823 					    sym_get_tristate_value(sym) == yes)
824 						continue;
825 				}
826 			}
827 			print_symbol_for_dotconfig(out, sym);
828 		}
829 	}
830 	fclose(out);
831 	return 0;
832 }
833 
834 int conf_write(const char *name)
835 {
836 	FILE *out;
837 	struct symbol *sym;
838 	struct menu *menu;
839 	const char *str;
840 	char tmpname[PATH_MAX + 1], oldname[PATH_MAX + 1];
841 	char *env;
842 	bool need_newline = false;
843 
844 	if (!name)
845 		name = conf_get_configname();
846 
847 	if (!*name) {
848 		fprintf(stderr, "config name is empty\n");
849 		return -1;
850 	}
851 
852 	if (is_dir(name)) {
853 		fprintf(stderr, "%s: Is a directory\n", name);
854 		return -1;
855 	}
856 
857 	if (make_parent_dir(name))
858 		return -1;
859 
860 	env = getenv("KCONFIG_OVERWRITECONFIG");
861 	if (env && *env) {
862 		*tmpname = 0;
863 		out = fopen(name, "w");
864 	} else {
865 		snprintf(tmpname, sizeof(tmpname), "%s.%d.tmp",
866 			 name, (int)getpid());
867 		out = fopen(tmpname, "w");
868 	}
869 	if (!out)
870 		return 1;
871 
872 	conf_write_heading(out, &comment_style_pound);
873 
874 	if (!conf_get_changed())
875 		sym_clear_all_valid();
876 
877 	menu = rootmenu.list;
878 	while (menu) {
879 		sym = menu->sym;
880 		if (!sym) {
881 			if (!menu_is_visible(menu))
882 				goto next;
883 			str = menu_get_prompt(menu);
884 			fprintf(out, "\n"
885 				     "#\n"
886 				     "# %s\n"
887 				     "#\n", str);
888 			need_newline = false;
889 		} else if (!sym_is_choice(sym) &&
890 			   !(sym->flags & SYMBOL_WRITTEN)) {
891 			sym_calc_value(sym);
892 			if (!(sym->flags & SYMBOL_WRITE))
893 				goto next;
894 			if (need_newline) {
895 				fprintf(out, "\n");
896 				need_newline = false;
897 			}
898 			sym->flags |= SYMBOL_WRITTEN;
899 			print_symbol_for_dotconfig(out, sym);
900 		}
901 
902 next:
903 		if (menu->list) {
904 			menu = menu->list;
905 			continue;
906 		}
907 
908 end_check:
909 		if (!menu->sym && menu_is_visible(menu) && menu != &rootmenu &&
910 		    menu->prompt->type == P_MENU) {
911 			fprintf(out, "# end of %s\n", menu_get_prompt(menu));
912 			need_newline = true;
913 		}
914 
915 		if (menu->next) {
916 			menu = menu->next;
917 		} else {
918 			menu = menu->parent;
919 			if (menu)
920 				goto end_check;
921 		}
922 	}
923 	fclose(out);
924 
925 	for_all_symbols(sym)
926 		sym->flags &= ~SYMBOL_WRITTEN;
927 
928 	if (*tmpname) {
929 		if (is_same(name, tmpname)) {
930 			conf_message("No change to %s", name);
931 			unlink(tmpname);
932 			conf_set_changed(false);
933 			return 0;
934 		}
935 
936 		snprintf(oldname, sizeof(oldname), "%s.old", name);
937 		rename(name, oldname);
938 		if (rename(tmpname, name))
939 			return 1;
940 	}
941 
942 	conf_message("configuration written to %s", name);
943 
944 	conf_set_changed(false);
945 
946 	return 0;
947 }
948 
949 /* write a dependency file as used by kbuild to track dependencies */
950 static int conf_write_autoconf_cmd(const char *autoconf_name)
951 {
952 	char name[PATH_MAX], tmp[PATH_MAX];
953 	FILE *out;
954 	int ret;
955 
956 	ret = snprintf(name, sizeof(name), "%s.cmd", autoconf_name);
957 	if (ret >= sizeof(name)) /* check truncation */
958 		return -1;
959 
960 	if (make_parent_dir(name))
961 		return -1;
962 
963 	ret = snprintf(tmp, sizeof(tmp), "%s.cmd.tmp", autoconf_name);
964 	if (ret >= sizeof(tmp)) /* check truncation */
965 		return -1;
966 
967 	out = fopen(tmp, "w");
968 	if (!out) {
969 		perror("fopen");
970 		return -1;
971 	}
972 
973 	fprintf(out, "autoconfig := %s\n", autoconf_name);
974 
975 	fputs(str_get(&autoconf_cmd), out);
976 
977 	fflush(out);
978 	ret = ferror(out); /* error check for all fprintf() calls */
979 	fclose(out);
980 	if (ret)
981 		return -1;
982 
983 	if (rename(tmp, name)) {
984 		perror("rename");
985 		return -1;
986 	}
987 
988 	return 0;
989 }
990 
991 static int conf_touch_deps(void)
992 {
993 	const char *name, *tmp;
994 	struct symbol *sym;
995 	int res;
996 
997 	name = conf_get_autoconfig_name();
998 	tmp = strrchr(name, '/');
999 	depfile_prefix_len = tmp ? tmp - name + 1 : 0;
1000 	if (depfile_prefix_len + 1 > sizeof(depfile_path))
1001 		return -1;
1002 
1003 	strncpy(depfile_path, name, depfile_prefix_len);
1004 	depfile_path[depfile_prefix_len] = 0;
1005 
1006 	conf_read_simple(name, S_DEF_AUTO);
1007 	sym_calc_value(modules_sym);
1008 
1009 	for_all_symbols(sym) {
1010 		sym_calc_value(sym);
1011 		if (sym_is_choice(sym))
1012 			continue;
1013 		if (sym->flags & SYMBOL_WRITE) {
1014 			if (sym->flags & SYMBOL_DEF_AUTO) {
1015 				/*
1016 				 * symbol has old and new value,
1017 				 * so compare them...
1018 				 */
1019 				switch (sym->type) {
1020 				case S_BOOLEAN:
1021 				case S_TRISTATE:
1022 					if (sym_get_tristate_value(sym) ==
1023 					    sym->def[S_DEF_AUTO].tri)
1024 						continue;
1025 					break;
1026 				case S_STRING:
1027 				case S_HEX:
1028 				case S_INT:
1029 					if (!strcmp(sym_get_string_value(sym),
1030 						    sym->def[S_DEF_AUTO].val))
1031 						continue;
1032 					break;
1033 				default:
1034 					break;
1035 				}
1036 			} else {
1037 				/*
1038 				 * If there is no old value, only 'no' (unset)
1039 				 * is allowed as new value.
1040 				 */
1041 				switch (sym->type) {
1042 				case S_BOOLEAN:
1043 				case S_TRISTATE:
1044 					if (sym_get_tristate_value(sym) == no)
1045 						continue;
1046 					break;
1047 				default:
1048 					break;
1049 				}
1050 			}
1051 		} else if (!(sym->flags & SYMBOL_DEF_AUTO))
1052 			/* There is neither an old nor a new value. */
1053 			continue;
1054 		/* else
1055 		 *	There is an old value, but no new value ('no' (unset)
1056 		 *	isn't saved in auto.conf, so the old value is always
1057 		 *	different from 'no').
1058 		 */
1059 
1060 		res = conf_touch_dep(sym->name);
1061 		if (res)
1062 			return res;
1063 	}
1064 
1065 	return 0;
1066 }
1067 
1068 static int __conf_write_autoconf(const char *filename,
1069 				 void (*print_symbol)(FILE *, struct symbol *),
1070 				 const struct comment_style *comment_style)
1071 {
1072 	char tmp[PATH_MAX];
1073 	FILE *file;
1074 	struct symbol *sym;
1075 	int ret;
1076 
1077 	if (make_parent_dir(filename))
1078 		return -1;
1079 
1080 	ret = snprintf(tmp, sizeof(tmp), "%s.tmp", filename);
1081 	if (ret >= sizeof(tmp)) /* check truncation */
1082 		return -1;
1083 
1084 	file = fopen(tmp, "w");
1085 	if (!file) {
1086 		perror("fopen");
1087 		return -1;
1088 	}
1089 
1090 	conf_write_heading(file, comment_style);
1091 
1092 	for_all_symbols(sym)
1093 		if ((sym->flags & SYMBOL_WRITE) && sym->name)
1094 			print_symbol(file, sym);
1095 
1096 	fflush(file);
1097 	/* check possible errors in conf_write_heading() and print_symbol() */
1098 	ret = ferror(file);
1099 	fclose(file);
1100 	if (ret)
1101 		return -1;
1102 
1103 	if (rename(tmp, filename)) {
1104 		perror("rename");
1105 		return -1;
1106 	}
1107 
1108 	return 0;
1109 }
1110 
1111 int conf_write_autoconf(int overwrite)
1112 {
1113 	struct symbol *sym;
1114 	const char *autoconf_name = conf_get_autoconfig_name();
1115 	int ret;
1116 
1117 	if (!overwrite && is_present(autoconf_name))
1118 		return 0;
1119 
1120 	ret = conf_write_autoconf_cmd(autoconf_name);
1121 	if (ret)
1122 		return -1;
1123 
1124 	if (conf_touch_deps())
1125 		return 1;
1126 
1127 	for_all_symbols(sym)
1128 		sym_calc_value(sym);
1129 
1130 	ret = __conf_write_autoconf(conf_get_autoheader_name(),
1131 				    print_symbol_for_c,
1132 				    &comment_style_c);
1133 	if (ret)
1134 		return ret;
1135 
1136 	ret = __conf_write_autoconf(conf_get_rustccfg_name(),
1137 				    print_symbol_for_rustccfg,
1138 				    NULL);
1139 	if (ret)
1140 		return ret;
1141 
1142 	/*
1143 	 * Create include/config/auto.conf. This must be the last step because
1144 	 * Kbuild has a dependency on auto.conf and this marks the successful
1145 	 * completion of the previous steps.
1146 	 */
1147 	ret = __conf_write_autoconf(conf_get_autoconfig_name(),
1148 				    print_symbol_for_autoconf,
1149 				    &comment_style_pound);
1150 	if (ret)
1151 		return ret;
1152 
1153 	return 0;
1154 }
1155 
1156 static bool conf_changed;
1157 static void (*conf_changed_callback)(void);
1158 
1159 void conf_set_changed(bool val)
1160 {
1161 	bool changed = conf_changed != val;
1162 
1163 	conf_changed = val;
1164 
1165 	if (conf_changed_callback && changed)
1166 		conf_changed_callback();
1167 }
1168 
1169 bool conf_get_changed(void)
1170 {
1171 	return conf_changed;
1172 }
1173 
1174 void conf_set_changed_callback(void (*fn)(void))
1175 {
1176 	conf_changed_callback = fn;
1177 }
1178 
1179 void set_all_choice_values(struct symbol *csym)
1180 {
1181 	struct property *prop;
1182 	struct symbol *sym;
1183 	struct expr *e;
1184 
1185 	prop = sym_get_choice_prop(csym);
1186 
1187 	/*
1188 	 * Set all non-assinged choice values to no
1189 	 */
1190 	expr_list_for_each_sym(prop->expr, e, sym) {
1191 		if (!sym_has_value(sym))
1192 			sym->def[S_DEF_USER].tri = no;
1193 	}
1194 	csym->flags |= SYMBOL_DEF_USER;
1195 	/* clear VALID to get value calculated */
1196 	csym->flags &= ~(SYMBOL_VALID | SYMBOL_NEED_SET_CHOICE_VALUES);
1197 }
1198