xref: /linux/scripts/kconfig/confdata.c (revision 645323a7f4e55bb3abb0cb003b6b9dc715c8dc21)
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 <xalloc.h>
22 #include "internal.h"
23 #include "lkc.h"
24 
25 struct gstr autoconf_cmd;
26 
27 /* return true if 'path' exists, false otherwise */
28 static bool is_present(const char *path)
29 {
30 	struct stat st;
31 
32 	return !stat(path, &st);
33 }
34 
35 /* return true if 'path' exists and it is a directory, false otherwise */
36 static bool is_dir(const char *path)
37 {
38 	struct stat st;
39 
40 	if (stat(path, &st))
41 		return false;
42 
43 	return S_ISDIR(st.st_mode);
44 }
45 
46 /* return true if the given two files are the same, false otherwise */
47 static bool is_same(const char *file1, const char *file2)
48 {
49 	int fd1, fd2;
50 	struct stat st1, st2;
51 	void *map1, *map2;
52 	bool ret = false;
53 
54 	fd1 = open(file1, O_RDONLY);
55 	if (fd1 < 0)
56 		return ret;
57 
58 	fd2 = open(file2, O_RDONLY);
59 	if (fd2 < 0)
60 		goto close1;
61 
62 	ret = fstat(fd1, &st1);
63 	if (ret)
64 		goto close2;
65 	ret = fstat(fd2, &st2);
66 	if (ret)
67 		goto close2;
68 
69 	if (st1.st_size != st2.st_size)
70 		goto close2;
71 
72 	map1 = mmap(NULL, st1.st_size, PROT_READ, MAP_PRIVATE, fd1, 0);
73 	if (map1 == MAP_FAILED)
74 		goto close2;
75 
76 	map2 = mmap(NULL, st2.st_size, PROT_READ, MAP_PRIVATE, fd2, 0);
77 	if (map2 == MAP_FAILED)
78 		goto close2;
79 
80 	if (memcmp(map1, map2, st1.st_size))
81 		goto close2;
82 
83 	ret = true;
84 close2:
85 	close(fd2);
86 close1:
87 	close(fd1);
88 
89 	return ret;
90 }
91 
92 /*
93  * Create the parent directory of the given path.
94  *
95  * For example, if 'include/config/auto.conf' is given, create 'include/config'.
96  */
97 static int make_parent_dir(const char *path)
98 {
99 	char tmp[PATH_MAX + 1];
100 	char *p;
101 
102 	strncpy(tmp, path, sizeof(tmp));
103 	tmp[sizeof(tmp) - 1] = 0;
104 
105 	/* Remove the base name. Just return if nothing is left */
106 	p = strrchr(tmp, '/');
107 	if (!p)
108 		return 0;
109 	*(p + 1) = 0;
110 
111 	/* Just in case it is an absolute path */
112 	p = tmp;
113 	while (*p == '/')
114 		p++;
115 
116 	while ((p = strchr(p, '/'))) {
117 		*p = 0;
118 
119 		/* skip if the directory exists */
120 		if (!is_dir(tmp) && mkdir(tmp, 0755))
121 			return -1;
122 
123 		*p = '/';
124 		while (*p == '/')
125 			p++;
126 	}
127 
128 	return 0;
129 }
130 
131 static char depfile_path[PATH_MAX];
132 static size_t depfile_prefix_len;
133 
134 /* touch depfile for symbol 'name' */
135 static int conf_touch_dep(const char *name)
136 {
137 	int fd;
138 
139 	/* check overflow: prefix + name + '\0' must fit in buffer. */
140 	if (depfile_prefix_len + strlen(name) + 1 > sizeof(depfile_path))
141 		return -1;
142 
143 	strcpy(depfile_path + depfile_prefix_len, name);
144 
145 	fd = open(depfile_path, O_WRONLY | O_CREAT | O_TRUNC, 0644);
146 	if (fd == -1)
147 		return -1;
148 	close(fd);
149 
150 	return 0;
151 }
152 
153 static void conf_warning(const char *fmt, ...)
154 	__attribute__ ((format (printf, 1, 2)));
155 
156 static void conf_message(const char *fmt, ...)
157 	__attribute__ ((format (printf, 1, 2)));
158 
159 static const char *conf_filename;
160 static int conf_lineno, conf_warnings;
161 
162 bool conf_errors(void)
163 {
164 	if (conf_warnings)
165 		return getenv("KCONFIG_WERROR");
166 	return false;
167 }
168 
169 static void conf_warning(const char *fmt, ...)
170 {
171 	va_list ap;
172 	va_start(ap, fmt);
173 	fprintf(stderr, "%s:%d:warning: ", conf_filename, conf_lineno);
174 	vfprintf(stderr, fmt, ap);
175 	fprintf(stderr, "\n");
176 	va_end(ap);
177 	conf_warnings++;
178 }
179 
180 static void conf_default_message_callback(const char *s)
181 {
182 	printf("#\n# ");
183 	printf("%s", s);
184 	printf("\n#\n");
185 }
186 
187 static void (*conf_message_callback)(const char *s) =
188 	conf_default_message_callback;
189 void conf_set_message_callback(void (*fn)(const char *s))
190 {
191 	conf_message_callback = fn;
192 }
193 
194 static void conf_message(const char *fmt, ...)
195 {
196 	va_list ap;
197 	char buf[4096];
198 
199 	if (!conf_message_callback)
200 		return;
201 
202 	va_start(ap, fmt);
203 
204 	vsnprintf(buf, sizeof(buf), fmt, ap);
205 	conf_message_callback(buf);
206 	va_end(ap);
207 }
208 
209 static void conf_changed_input_warning(const char *s)
210 {
211 	fputs(s, stderr);
212 }
213 
214 static bool conf_warn_changed_input_enabled(void)
215 {
216 	const char *env = getenv("KCONFIG_WARN_CHANGED_INPUT");
217 
218 	return env && *env;
219 }
220 
221 static const char *sym_get_user_value_string(struct symbol *sym)
222 {
223 	switch (sym->type) {
224 	case S_BOOLEAN:
225 	case S_TRISTATE:
226 		switch (sym->def[S_DEF_USER].tri) {
227 		case yes:
228 			return "y";
229 		case mod:
230 			return "m";
231 		default:
232 			return "n";
233 		}
234 	default:
235 		return sym->def[S_DEF_USER].val ?: "";
236 	}
237 }
238 
239 static bool sym_user_value_changed(struct symbol *sym)
240 {
241 	if (!sym_has_value(sym) || sym->type == S_UNKNOWN)
242 		return false;
243 
244 	switch (sym->type) {
245 	case S_BOOLEAN:
246 	case S_TRISTATE:
247 		return sym->def[S_DEF_USER].tri != sym_get_tristate_value(sym);
248 	default:
249 		return strcmp(sym_get_user_value_string(sym),
250 			      sym_get_string_value(sym));
251 	}
252 }
253 
254 static void conf_clear_written_flags(void)
255 {
256 	struct symbol *sym;
257 
258 	for_all_symbols(sym)
259 		sym->flags &= ~SYMBOL_WRITTEN;
260 }
261 
262 static void conf_append_changed_input_warning(struct gstr *gs,
263 					      struct symbol *sym,
264 					      bool *changed_input_found)
265 {
266 	if (!sym_user_value_changed(sym))
267 		return;
268 
269 	if (!*changed_input_found) {
270 		str_printf(gs,
271 			   "warning: user-provided values changed by Kconfig:\n");
272 		*changed_input_found = true;
273 	}
274 
275 	str_printf(gs, "  %s%s: %s -> %s\n",
276 		   CONFIG_, sym->name,
277 		   sym_get_user_value_string(sym),
278 		   sym_get_string_value(sym));
279 }
280 
281 const char *conf_get_configname(void)
282 {
283 	char *name = getenv("KCONFIG_CONFIG");
284 
285 	return name ? name : ".config";
286 }
287 
288 static const char *conf_get_autoconfig_name(void)
289 {
290 	char *name = getenv("KCONFIG_AUTOCONFIG");
291 
292 	return name ? name : "include/config/auto.conf";
293 }
294 
295 static const char *conf_get_autoheader_name(void)
296 {
297 	char *name = getenv("KCONFIG_AUTOHEADER");
298 
299 	return name ? name : "include/generated/autoconf.h";
300 }
301 
302 static const char *conf_get_rustccfg_name(void)
303 {
304 	char *name = getenv("KCONFIG_RUSTCCFG");
305 
306 	return name ? name : "include/generated/rustc_cfg";
307 }
308 
309 static int conf_set_sym_val(struct symbol *sym, int def, int def_flags, char *p)
310 {
311 	char *p2;
312 
313 	switch (sym->type) {
314 	case S_TRISTATE:
315 		if (p[0] == 'm') {
316 			sym->def[def].tri = mod;
317 			sym->flags |= def_flags;
318 			break;
319 		}
320 		/* fall through */
321 	case S_BOOLEAN:
322 		if (p[0] == 'y') {
323 			sym->def[def].tri = yes;
324 			sym->flags |= def_flags;
325 			break;
326 		}
327 		if (p[0] == 'n') {
328 			sym->def[def].tri = no;
329 			sym->flags |= def_flags;
330 			break;
331 		}
332 		if (def != S_DEF_AUTO)
333 			conf_warning("symbol value '%s' invalid for %s",
334 				     p, sym->name);
335 		return 1;
336 	case S_STRING:
337 		/* No escaping for S_DEF_AUTO (include/config/auto.conf) */
338 		if (def != S_DEF_AUTO) {
339 			if (*p++ != '"')
340 				break;
341 			for (p2 = p; (p2 = strpbrk(p2, "\"\\")); p2++) {
342 				if (*p2 == '"') {
343 					*p2 = 0;
344 					break;
345 				}
346 				memmove(p2, p2 + 1, strlen(p2));
347 			}
348 			if (!p2) {
349 				conf_warning("invalid string found");
350 				return 1;
351 			}
352 		}
353 		/* fall through */
354 	case S_INT:
355 	case S_HEX:
356 		if (sym_string_valid(sym, p)) {
357 			sym->def[def].val = xstrdup(p);
358 			sym->flags |= def_flags;
359 		} else {
360 			if (def != S_DEF_AUTO)
361 				conf_warning("symbol value '%s' invalid for %s",
362 					     p, sym->name);
363 			return 1;
364 		}
365 		break;
366 	default:
367 		;
368 	}
369 	return 0;
370 }
371 
372 /* like getline(), but the newline character is stripped away */
373 static ssize_t getline_stripped(char **lineptr, size_t *n, FILE *stream)
374 {
375 	ssize_t len;
376 
377 	len = getline(lineptr, n, stream);
378 
379 	if (len > 0 && (*lineptr)[len - 1] == '\n') {
380 		len--;
381 		(*lineptr)[len] = '\0';
382 
383 		if (len > 0 && (*lineptr)[len - 1] == '\r') {
384 			len--;
385 			(*lineptr)[len] = '\0';
386 		}
387 	}
388 
389 	return len;
390 }
391 
392 int conf_read_simple(const char *name, int def)
393 {
394 	FILE *in = NULL;
395 	char   *line = NULL;
396 	size_t  line_asize = 0;
397 	char *p, *val;
398 	struct symbol *sym;
399 	int def_flags;
400 	const char *warn_unknown, *sym_name;
401 
402 	warn_unknown = getenv("KCONFIG_WARN_UNKNOWN_SYMBOLS");
403 	if (name) {
404 		in = zconf_fopen(name);
405 	} else {
406 		char *env;
407 
408 		name = conf_get_configname();
409 		in = zconf_fopen(name);
410 		if (in)
411 			goto load;
412 		conf_set_changed(true);
413 
414 		env = getenv("KCONFIG_DEFCONFIG_LIST");
415 		if (!env)
416 			return 1;
417 
418 		while (1) {
419 			bool is_last;
420 
421 			while (isspace(*env))
422 				env++;
423 
424 			if (!*env)
425 				break;
426 
427 			p = env;
428 			while (*p && !isspace(*p))
429 				p++;
430 
431 			is_last = (*p == '\0');
432 
433 			*p = '\0';
434 
435 			name = env;
436 
437 			in = zconf_fopen(name);
438 			if (in) {
439 				conf_message("using defaults found in %s",
440 					     name);
441 				goto load;
442 			}
443 
444 			if (is_last)
445 				break;
446 
447 			env = p + 1;
448 		}
449 	}
450 	if (!in)
451 		return 1;
452 
453 load:
454 	conf_filename = name;
455 	conf_lineno = 0;
456 	conf_warnings = 0;
457 
458 	def_flags = SYMBOL_DEF << def;
459 	for_all_symbols(sym) {
460 		sym->flags &= ~def_flags;
461 		switch (sym->type) {
462 		case S_INT:
463 		case S_HEX:
464 		case S_STRING:
465 			free(sym->def[def].val);
466 			/* fall through */
467 		default:
468 			sym->def[def].val = NULL;
469 			sym->def[def].tri = no;
470 		}
471 	}
472 
473 	if (def == S_DEF_USER) {
474 		for_all_symbols(sym)
475 			sym->flags &= ~SYMBOL_VALID;
476 		expr_invalidate_all();
477 	}
478 
479 	while (getline_stripped(&line, &line_asize, in) != -1) {
480 		struct menu *choice;
481 
482 		conf_lineno++;
483 
484 		if (!line[0]) /* blank line */
485 			continue;
486 
487 		if (line[0] == '#') {
488 			if (line[1] != ' ')
489 				continue;
490 			p = line + 2;
491 			if (memcmp(p, CONFIG_, strlen(CONFIG_)))
492 				continue;
493 			sym_name = p + strlen(CONFIG_);
494 			p = strchr(sym_name, ' ');
495 			if (!p)
496 				continue;
497 			*p++ = 0;
498 			if (strcmp(p, "is not set"))
499 				continue;
500 
501 			val = "n";
502 		} else {
503 			if (memcmp(line, CONFIG_, strlen(CONFIG_))) {
504 				conf_warning("unexpected data: %s", line);
505 				continue;
506 			}
507 
508 			sym_name = line + strlen(CONFIG_);
509 			p = strchr(sym_name, '=');
510 			if (!p) {
511 				conf_warning("unexpected data: %s", line);
512 				continue;
513 			}
514 			*p = 0;
515 			val = p + 1;
516 		}
517 
518 		sym = sym_find(sym_name);
519 		if (!sym) {
520 			if (def == S_DEF_AUTO) {
521 				/*
522 				 * Reading from include/config/auto.conf.
523 				 * If CONFIG_FOO previously existed in auto.conf
524 				 * but it is missing now, include/config/FOO
525 				 * must be touched.
526 				 */
527 				conf_touch_dep(sym_name);
528 			} else {
529 				if (warn_unknown)
530 					conf_warning("unknown symbol: %s", sym_name);
531 
532 				conf_set_changed(true);
533 			}
534 			continue;
535 		}
536 
537 		if (sym->flags & def_flags)
538 			conf_warning("override: reassigning to symbol %s", sym->name);
539 
540 		if (conf_set_sym_val(sym, def, def_flags, val))
541 			continue;
542 
543 		if (def != S_DEF_USER)
544 			continue;
545 
546 		/*
547 		 * If this is a choice member, give it the highest priority.
548 		 * If conflicting CONFIG options are given from an input file,
549 		 * the last one wins.
550 		 */
551 		choice = sym_get_choice_menu(sym);
552 		if (choice)
553 			list_move(&sym->choice_link, &choice->choice_members);
554 	}
555 	free(line);
556 	fclose(in);
557 
558 	return 0;
559 }
560 
561 int conf_read(const char *name)
562 {
563 	struct symbol *sym;
564 
565 	conf_set_changed(false);
566 
567 	if (conf_read_simple(name, S_DEF_USER)) {
568 		sym_calc_value(modules_sym);
569 		return 1;
570 	}
571 
572 	sym_calc_value(modules_sym);
573 
574 	for_all_symbols(sym) {
575 		sym_calc_value(sym);
576 		if (sym_is_choice(sym))
577 			continue;
578 		if (sym_has_value(sym) && (sym->flags & SYMBOL_WRITE)) {
579 			/* check that calculated value agrees with saved value */
580 			switch (sym->type) {
581 			case S_BOOLEAN:
582 			case S_TRISTATE:
583 				if (sym->def[S_DEF_USER].tri == sym_get_tristate_value(sym))
584 					continue;
585 				break;
586 			default:
587 				if (!strcmp(sym->curr.val, sym->def[S_DEF_USER].val))
588 					continue;
589 				break;
590 			}
591 		} else if (!sym_has_value(sym) && !(sym->flags & SYMBOL_WRITE))
592 			/* no previous value and not saved */
593 			continue;
594 		conf_set_changed(true);
595 		/* maybe print value in verbose mode... */
596 	}
597 
598 	if (conf_warnings)
599 		conf_set_changed(true);
600 
601 	return 0;
602 }
603 
604 struct comment_style {
605 	const char *decoration;
606 	const char *prefix;
607 	const char *postfix;
608 };
609 
610 static const struct comment_style comment_style_pound = {
611 	.decoration = "#",
612 	.prefix = "#",
613 	.postfix = "#",
614 };
615 
616 static const struct comment_style comment_style_c = {
617 	.decoration = " *",
618 	.prefix = "/*",
619 	.postfix = " */",
620 };
621 
622 static void conf_write_heading(FILE *fp, const struct comment_style *cs)
623 {
624 	if (!cs)
625 		return;
626 
627 	fprintf(fp, "%s\n", cs->prefix);
628 
629 	fprintf(fp, "%s Automatically generated file; DO NOT EDIT.\n",
630 		cs->decoration);
631 
632 	fprintf(fp, "%s %s\n", cs->decoration, rootmenu.prompt->text);
633 
634 	fprintf(fp, "%s\n", cs->postfix);
635 }
636 
637 /* The returned pointer must be freed on the caller side */
638 static char *escape_string_value(const char *in)
639 {
640 	const char *p;
641 	char *out;
642 	size_t len;
643 
644 	len = strlen(in) + strlen("\"\"") + 1;
645 
646 	p = in;
647 	while (1) {
648 		p += strcspn(p, "\"\\");
649 
650 		if (p[0] == '\0')
651 			break;
652 
653 		len++;
654 		p++;
655 	}
656 
657 	out = xmalloc(len);
658 	out[0] = '\0';
659 
660 	strcat(out, "\"");
661 
662 	p = in;
663 	while (1) {
664 		len = strcspn(p, "\"\\");
665 		strncat(out, p, len);
666 		p += len;
667 
668 		if (p[0] == '\0')
669 			break;
670 
671 		strcat(out, "\\");
672 		strncat(out, p++, 1);
673 	}
674 
675 	strcat(out, "\"");
676 
677 	return out;
678 }
679 
680 enum output_n { OUTPUT_N, OUTPUT_N_AS_UNSET, OUTPUT_N_NONE };
681 
682 static void __print_symbol(FILE *fp, struct symbol *sym, enum output_n output_n,
683 			   bool escape_string)
684 {
685 	const char *val;
686 	char *escaped = NULL;
687 
688 	if (sym->type == S_UNKNOWN)
689 		return;
690 
691 	val = sym_get_string_value(sym);
692 
693 	if ((sym->type == S_BOOLEAN || sym->type == S_TRISTATE) &&
694 	    output_n != OUTPUT_N && *val == 'n') {
695 		if (output_n == OUTPUT_N_AS_UNSET)
696 			fprintf(fp, "# %s%s is not set\n", CONFIG_, sym->name);
697 		return;
698 	}
699 
700 	if (sym->type == S_STRING && escape_string) {
701 		escaped = escape_string_value(val);
702 		val = escaped;
703 	}
704 
705 	fprintf(fp, "%s%s=%s\n", CONFIG_, sym->name, val);
706 
707 	free(escaped);
708 }
709 
710 static void print_symbol_for_dotconfig(FILE *fp, struct symbol *sym)
711 {
712 	__print_symbol(fp, sym, OUTPUT_N_AS_UNSET, true);
713 }
714 
715 static void print_symbol_for_autoconf(FILE *fp, struct symbol *sym)
716 {
717 	__print_symbol(fp, sym, OUTPUT_N_NONE, false);
718 }
719 
720 void print_symbol_for_listconfig(struct symbol *sym)
721 {
722 	__print_symbol(stdout, sym, OUTPUT_N, true);
723 }
724 
725 static void print_symbol_for_c(FILE *fp, struct symbol *sym)
726 {
727 	const char *val;
728 	const char *sym_suffix = "";
729 	const char *val_prefix = "";
730 	char *escaped = NULL;
731 
732 	if (sym->type == S_UNKNOWN)
733 		return;
734 
735 	val = sym_get_string_value(sym);
736 
737 	switch (sym->type) {
738 	case S_BOOLEAN:
739 	case S_TRISTATE:
740 		switch (*val) {
741 		case 'n':
742 			return;
743 		case 'm':
744 			sym_suffix = "_MODULE";
745 			/* fall through */
746 		default:
747 			val = "1";
748 		}
749 		break;
750 	case S_HEX:
751 		if (val[0] != '0' || (val[1] != 'x' && val[1] != 'X'))
752 			val_prefix = "0x";
753 		break;
754 	case S_STRING:
755 		escaped = escape_string_value(val);
756 		val = escaped;
757 	default:
758 		break;
759 	}
760 
761 	fprintf(fp, "#define %s%s%s %s%s\n", CONFIG_, sym->name, sym_suffix,
762 		val_prefix, val);
763 
764 	free(escaped);
765 }
766 
767 static void print_symbol_for_rustccfg(FILE *fp, struct symbol *sym)
768 {
769 	const char *val;
770 	const char *val_prefix = "";
771 	char *val_prefixed = NULL;
772 	size_t val_prefixed_len;
773 	char *escaped = NULL;
774 
775 	if (sym->type == S_UNKNOWN)
776 		return;
777 
778 	val = sym_get_string_value(sym);
779 
780 	switch (sym->type) {
781 	case S_BOOLEAN:
782 	case S_TRISTATE:
783 		/*
784 		 * We do not care about disabled ones, i.e. no need for
785 		 * what otherwise are "comments" in other printers.
786 		 */
787 		if (*val == 'n')
788 			return;
789 
790 		/*
791 		 * To have similar functionality to the C macro `IS_ENABLED()`
792 		 * we provide an empty `--cfg CONFIG_X` here in both `y`
793 		 * and `m` cases.
794 		 *
795 		 * Then, the common `fprintf()` below will also give us
796 		 * a `--cfg CONFIG_X="y"` or `--cfg CONFIG_X="m"`, which can
797 		 * be used as the equivalent of `IS_BUILTIN()`/`IS_MODULE()`.
798 		 */
799 		fprintf(fp, "--cfg=%s%s\n", CONFIG_, sym->name);
800 		break;
801 	case S_HEX:
802 		if (val[0] != '0' || (val[1] != 'x' && val[1] != 'X'))
803 			val_prefix = "0x";
804 		break;
805 	default:
806 		break;
807 	}
808 
809 	if (strlen(val_prefix) > 0) {
810 		val_prefixed_len = strlen(val) + strlen(val_prefix) + 1;
811 		val_prefixed = xmalloc(val_prefixed_len);
812 		snprintf(val_prefixed, val_prefixed_len, "%s%s", val_prefix, val);
813 		val = val_prefixed;
814 	}
815 
816 	/* All values get escaped: the `--cfg` option only takes strings */
817 	escaped = escape_string_value(val);
818 	val = escaped;
819 
820 	fprintf(fp, "--cfg=%s%s=%s\n", CONFIG_, sym->name, val);
821 
822 	free(escaped);
823 	free(val_prefixed);
824 }
825 
826 /*
827  * Write out a minimal config.
828  * All values that has default values are skipped as this is redundant.
829  */
830 int conf_write_defconfig(const char *filename)
831 {
832 	struct symbol *sym;
833 	struct menu *menu;
834 	struct gstr gs;
835 	FILE *out;
836 	bool warn_changed_input = conf_warn_changed_input_enabled();
837 	bool changed_input_found = false;
838 
839 	out = fopen(filename, "w");
840 	if (!out)
841 		return 1;
842 	gs = str_new();
843 
844 	sym_clear_all_valid();
845 
846 	menu_for_each_entry(menu) {
847 		struct menu *choice;
848 
849 		sym = menu->sym;
850 
851 		if (!sym || sym_is_choice(sym) || sym->flags & SYMBOL_WRITTEN)
852 			continue;
853 
854 		sym_calc_value(sym);
855 		if (warn_changed_input)
856 			conf_append_changed_input_warning(&gs, sym,
857 							  &changed_input_found);
858 		sym->flags |= SYMBOL_WRITTEN;
859 		if (!(sym->flags & SYMBOL_WRITE))
860 			continue;
861 		sym->flags &= ~SYMBOL_WRITE;
862 		/* Skip unchangeable symbols */
863 		if (!sym_is_changeable(sym))
864 			continue;
865 		/* Skip symbols that are equal to the default */
866 		if (!strcmp(sym_get_string_value(sym), sym_get_string_default(sym)))
867 			continue;
868 
869 		/* Skip choice values that are equal to the default */
870 		choice = sym_get_choice_menu(sym);
871 		if (choice) {
872 			struct symbol *ds;
873 
874 			ds = sym_choice_default(choice);
875 			if (sym == ds && sym_get_tristate_value(sym) == yes)
876 				continue;
877 		}
878 		print_symbol_for_dotconfig(out, sym);
879 	}
880 	fclose(out);
881 
882 	conf_clear_written_flags();
883 
884 	if (changed_input_found)
885 		conf_changed_input_warning(str_get(&gs));
886 
887 	str_free(&gs);
888 	return 0;
889 }
890 
891 int conf_write(const char *name)
892 {
893 	FILE *out;
894 	struct symbol *sym;
895 	struct menu *menu;
896 	const char *str;
897 	char tmpname[PATH_MAX + 1], oldname[PATH_MAX + 1];
898 	char *env;
899 	struct gstr gs;
900 	bool need_newline = false;
901 	bool warn_changed_input = conf_warn_changed_input_enabled();
902 	bool changed_input_found = false;
903 
904 	if (!name)
905 		name = conf_get_configname();
906 
907 	if (!*name) {
908 		fprintf(stderr, "config name is empty\n");
909 		return -1;
910 	}
911 
912 	if (is_dir(name)) {
913 		fprintf(stderr, "%s: Is a directory\n", name);
914 		return -1;
915 	}
916 
917 	if (make_parent_dir(name))
918 		return -1;
919 
920 	env = getenv("KCONFIG_OVERWRITECONFIG");
921 	if (env && *env) {
922 		*tmpname = 0;
923 		out = fopen(name, "w");
924 	} else {
925 		snprintf(tmpname, sizeof(tmpname), "%s.%d.tmp",
926 			 name, (int)getpid());
927 		out = fopen(tmpname, "w");
928 	}
929 	if (!out)
930 		return 1;
931 	gs = str_new();
932 
933 	conf_write_heading(out, &comment_style_pound);
934 
935 	if (!conf_get_changed())
936 		sym_clear_all_valid();
937 
938 	menu = rootmenu.list;
939 	while (menu) {
940 		sym = menu->sym;
941 		if (!sym) {
942 			if (!menu_is_visible(menu))
943 				goto next;
944 			str = menu_get_prompt(menu);
945 			fprintf(out, "\n"
946 				     "#\n"
947 				     "# %s\n"
948 				     "#\n", str);
949 			need_newline = false;
950 		} else if (!sym_is_choice(sym) &&
951 			   !(sym->flags & SYMBOL_WRITTEN)) {
952 			sym_calc_value(sym);
953 			if (warn_changed_input)
954 				conf_append_changed_input_warning(&gs, sym,
955 								  &changed_input_found);
956 			sym->flags |= SYMBOL_WRITTEN;
957 			if (!(sym->flags & SYMBOL_WRITE))
958 				goto next;
959 			if (need_newline) {
960 				fprintf(out, "\n");
961 				need_newline = false;
962 			}
963 			print_symbol_for_dotconfig(out, sym);
964 		}
965 
966 next:
967 		if (menu->list) {
968 			menu = menu->list;
969 			continue;
970 		}
971 
972 end_check:
973 		if (!menu->sym && menu_is_visible(menu) && menu != &rootmenu &&
974 		    menu->prompt->type == P_MENU) {
975 			fprintf(out, "# end of %s\n", menu_get_prompt(menu));
976 			need_newline = true;
977 		}
978 
979 		if (menu->next) {
980 			menu = menu->next;
981 		} else {
982 			menu = menu->parent;
983 			if (menu)
984 				goto end_check;
985 		}
986 	}
987 	fclose(out);
988 
989 	conf_clear_written_flags();
990 
991 	if (changed_input_found)
992 		conf_changed_input_warning(str_get(&gs));
993 
994 	str_free(&gs);
995 
996 	if (*tmpname) {
997 		if (is_same(name, tmpname)) {
998 			conf_message("No change to %s", name);
999 			unlink(tmpname);
1000 			conf_set_changed(false);
1001 			return 0;
1002 		}
1003 
1004 		snprintf(oldname, sizeof(oldname), "%s.old", name);
1005 		rename(name, oldname);
1006 		if (rename(tmpname, name))
1007 			return 1;
1008 	}
1009 
1010 	conf_message("configuration written to %s", name);
1011 
1012 	conf_set_changed(false);
1013 
1014 	return 0;
1015 }
1016 
1017 /* write a dependency file as used by kbuild to track dependencies */
1018 static int conf_write_autoconf_cmd(const char *autoconf_name)
1019 {
1020 	char name[PATH_MAX], tmp[PATH_MAX];
1021 	FILE *out;
1022 	int ret;
1023 
1024 	ret = snprintf(name, sizeof(name), "%s.cmd", autoconf_name);
1025 	if (ret >= sizeof(name)) /* check truncation */
1026 		return -1;
1027 
1028 	if (make_parent_dir(name))
1029 		return -1;
1030 
1031 	ret = snprintf(tmp, sizeof(tmp), "%s.cmd.tmp", autoconf_name);
1032 	if (ret >= sizeof(tmp)) /* check truncation */
1033 		return -1;
1034 
1035 	out = fopen(tmp, "w");
1036 	if (!out) {
1037 		perror("fopen");
1038 		return -1;
1039 	}
1040 
1041 	fprintf(out, "autoconfig := %s\n", autoconf_name);
1042 
1043 	fputs(str_get(&autoconf_cmd), out);
1044 
1045 	fflush(out);
1046 	ret = ferror(out); /* error check for all fprintf() calls */
1047 	fclose(out);
1048 	if (ret)
1049 		return -1;
1050 
1051 	if (rename(tmp, name)) {
1052 		perror("rename");
1053 		return -1;
1054 	}
1055 
1056 	return 0;
1057 }
1058 
1059 static int conf_touch_deps(void)
1060 {
1061 	const char *name, *tmp;
1062 	struct symbol *sym;
1063 	int res;
1064 
1065 	name = conf_get_autoconfig_name();
1066 	tmp = strrchr(name, '/');
1067 	depfile_prefix_len = tmp ? tmp - name + 1 : 0;
1068 	if (depfile_prefix_len + 1 > sizeof(depfile_path))
1069 		return -1;
1070 
1071 	strncpy(depfile_path, name, depfile_prefix_len);
1072 	depfile_path[depfile_prefix_len] = 0;
1073 
1074 	conf_read_simple(name, S_DEF_AUTO);
1075 
1076 	for_all_symbols(sym) {
1077 		if (sym_is_choice(sym))
1078 			continue;
1079 		if (sym->flags & SYMBOL_WRITE) {
1080 			if (sym->flags & SYMBOL_DEF_AUTO) {
1081 				/*
1082 				 * symbol has old and new value,
1083 				 * so compare them...
1084 				 */
1085 				switch (sym->type) {
1086 				case S_BOOLEAN:
1087 				case S_TRISTATE:
1088 					if (sym_get_tristate_value(sym) ==
1089 					    sym->def[S_DEF_AUTO].tri)
1090 						continue;
1091 					break;
1092 				case S_STRING:
1093 				case S_HEX:
1094 				case S_INT:
1095 					if (!strcmp(sym_get_string_value(sym),
1096 						    sym->def[S_DEF_AUTO].val))
1097 						continue;
1098 					break;
1099 				default:
1100 					break;
1101 				}
1102 			} else {
1103 				/*
1104 				 * If there is no old value, only 'no' (unset)
1105 				 * is allowed as new value.
1106 				 */
1107 				switch (sym->type) {
1108 				case S_BOOLEAN:
1109 				case S_TRISTATE:
1110 					if (sym_get_tristate_value(sym) == no)
1111 						continue;
1112 					break;
1113 				default:
1114 					break;
1115 				}
1116 			}
1117 		} else if (!(sym->flags & SYMBOL_DEF_AUTO))
1118 			/* There is neither an old nor a new value. */
1119 			continue;
1120 		/* else
1121 		 *	There is an old value, but no new value ('no' (unset)
1122 		 *	isn't saved in auto.conf, so the old value is always
1123 		 *	different from 'no').
1124 		 */
1125 
1126 		res = conf_touch_dep(sym->name);
1127 		if (res)
1128 			return res;
1129 	}
1130 
1131 	return 0;
1132 }
1133 
1134 static int __conf_write_autoconf(const char *filename,
1135 				 void (*print_symbol)(FILE *, struct symbol *),
1136 				 const struct comment_style *comment_style)
1137 {
1138 	char tmp[PATH_MAX];
1139 	FILE *file;
1140 	struct symbol *sym;
1141 	int ret;
1142 
1143 	if (make_parent_dir(filename))
1144 		return -1;
1145 
1146 	ret = snprintf(tmp, sizeof(tmp), "%s.tmp", filename);
1147 	if (ret >= sizeof(tmp)) /* check truncation */
1148 		return -1;
1149 
1150 	file = fopen(tmp, "w");
1151 	if (!file) {
1152 		perror("fopen");
1153 		return -1;
1154 	}
1155 
1156 	conf_write_heading(file, comment_style);
1157 
1158 	for_all_symbols(sym)
1159 		if ((sym->flags & SYMBOL_WRITE) && sym->name)
1160 			print_symbol(file, sym);
1161 
1162 	fflush(file);
1163 	/* check possible errors in conf_write_heading() and print_symbol() */
1164 	ret = ferror(file);
1165 	fclose(file);
1166 	if (ret)
1167 		return -1;
1168 
1169 	if (rename(tmp, filename)) {
1170 		perror("rename");
1171 		return -1;
1172 	}
1173 
1174 	return 0;
1175 }
1176 
1177 int conf_write_autoconf(int overwrite)
1178 {
1179 	struct symbol *sym;
1180 	const char *autoconf_name = conf_get_autoconfig_name();
1181 	int ret;
1182 
1183 	if (!overwrite && is_present(autoconf_name))
1184 		return 0;
1185 
1186 	ret = conf_write_autoconf_cmd(autoconf_name);
1187 	if (ret)
1188 		return -1;
1189 
1190 	for_all_symbols(sym)
1191 		sym_calc_value(sym);
1192 
1193 	if (conf_touch_deps())
1194 		return 1;
1195 
1196 	ret = __conf_write_autoconf(conf_get_autoheader_name(),
1197 				    print_symbol_for_c,
1198 				    &comment_style_c);
1199 	if (ret)
1200 		return ret;
1201 
1202 	ret = __conf_write_autoconf(conf_get_rustccfg_name(),
1203 				    print_symbol_for_rustccfg,
1204 				    NULL);
1205 	if (ret)
1206 		return ret;
1207 
1208 	/*
1209 	 * Create include/config/auto.conf. This must be the last step because
1210 	 * Kbuild has a dependency on auto.conf and this marks the successful
1211 	 * completion of the previous steps.
1212 	 */
1213 	ret = __conf_write_autoconf(conf_get_autoconfig_name(),
1214 				    print_symbol_for_autoconf,
1215 				    &comment_style_pound);
1216 	if (ret)
1217 		return ret;
1218 
1219 	return 0;
1220 }
1221 
1222 static bool conf_changed;
1223 static void (*conf_changed_callback)(bool);
1224 
1225 void conf_set_changed(bool val)
1226 {
1227 	if (conf_changed_callback && conf_changed != val)
1228 		conf_changed_callback(val);
1229 
1230 	conf_changed = val;
1231 }
1232 
1233 bool conf_get_changed(void)
1234 {
1235 	return conf_changed;
1236 }
1237 
1238 void conf_set_changed_callback(void (*fn)(bool))
1239 {
1240 	conf_changed_callback = fn;
1241 }
1242