xref: /openbmc/linux/scripts/kconfig/confdata.c (revision ae213c44)
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 <ctype.h>
9 #include <errno.h>
10 #include <fcntl.h>
11 #include <limits.h>
12 #include <stdarg.h>
13 #include <stdio.h>
14 #include <stdlib.h>
15 #include <string.h>
16 #include <time.h>
17 #include <unistd.h>
18 
19 #include "lkc.h"
20 
21 /* return true if 'path' exists, false otherwise */
22 static bool is_present(const char *path)
23 {
24 	struct stat st;
25 
26 	return !stat(path, &st);
27 }
28 
29 /* return true if 'path' exists and it is a directory, false otherwise */
30 static bool is_dir(const char *path)
31 {
32 	struct stat st;
33 
34 	if (stat(path, &st))
35 		return 0;
36 
37 	return S_ISDIR(st.st_mode);
38 }
39 
40 /* return true if the given two files are the same, false otherwise */
41 static bool is_same(const char *file1, const char *file2)
42 {
43 	int fd1, fd2;
44 	struct stat st1, st2;
45 	void *map1, *map2;
46 	bool ret = false;
47 
48 	fd1 = open(file1, O_RDONLY);
49 	if (fd1 < 0)
50 		return ret;
51 
52 	fd2 = open(file2, O_RDONLY);
53 	if (fd2 < 0)
54 		goto close1;
55 
56 	ret = fstat(fd1, &st1);
57 	if (ret)
58 		goto close2;
59 	ret = fstat(fd2, &st2);
60 	if (ret)
61 		goto close2;
62 
63 	if (st1.st_size != st2.st_size)
64 		goto close2;
65 
66 	map1 = mmap(NULL, st1.st_size, PROT_READ, MAP_PRIVATE, fd1, 0);
67 	if (map1 == MAP_FAILED)
68 		goto close2;
69 
70 	map2 = mmap(NULL, st2.st_size, PROT_READ, MAP_PRIVATE, fd2, 0);
71 	if (map2 == MAP_FAILED)
72 		goto close2;
73 
74 	if (bcmp(map1, map2, st1.st_size))
75 		goto close2;
76 
77 	ret = true;
78 close2:
79 	close(fd2);
80 close1:
81 	close(fd1);
82 
83 	return ret;
84 }
85 
86 /*
87  * Create the parent directory of the given path.
88  *
89  * For example, if 'include/config/auto.conf' is given, create 'include/config'.
90  */
91 static int make_parent_dir(const char *path)
92 {
93 	char tmp[PATH_MAX + 1];
94 	char *p;
95 
96 	strncpy(tmp, path, sizeof(tmp));
97 	tmp[sizeof(tmp) - 1] = 0;
98 
99 	/* Remove the base name. Just return if nothing is left */
100 	p = strrchr(tmp, '/');
101 	if (!p)
102 		return 0;
103 	*(p + 1) = 0;
104 
105 	/* Just in case it is an absolute path */
106 	p = tmp;
107 	while (*p == '/')
108 		p++;
109 
110 	while ((p = strchr(p, '/'))) {
111 		*p = 0;
112 
113 		/* skip if the directory exists */
114 		if (!is_dir(tmp) && mkdir(tmp, 0755))
115 			return -1;
116 
117 		*p = '/';
118 		while (*p == '/')
119 			p++;
120 	}
121 
122 	return 0;
123 }
124 
125 static char depfile_path[PATH_MAX];
126 static size_t depfile_prefix_len;
127 
128 /* touch depfile for symbol 'name' */
129 static int conf_touch_dep(const char *name)
130 {
131 	int fd, ret;
132 	const char *s;
133 	char *d, c;
134 
135 	/* check overflow: prefix + name + ".h" + '\0' must fit in buffer. */
136 	if (depfile_prefix_len + strlen(name) + 3 > sizeof(depfile_path))
137 		return -1;
138 
139 	d = depfile_path + depfile_prefix_len;
140 	s = name;
141 
142 	while ((c = *s++))
143 		*d++ = (c == '_') ? '/' : tolower(c);
144 	strcpy(d, ".h");
145 
146 	/* Assume directory path already exists. */
147 	fd = open(depfile_path, O_WRONLY | O_CREAT | O_TRUNC, 0644);
148 	if (fd == -1) {
149 		if (errno != ENOENT)
150 			return -1;
151 
152 		ret = make_parent_dir(depfile_path);
153 		if (ret)
154 			return ret;
155 
156 		/* Try it again. */
157 		fd = open(depfile_path, O_WRONLY | O_CREAT | O_TRUNC, 0644);
158 		if (fd == -1)
159 			return -1;
160 	}
161 	close(fd);
162 
163 	return 0;
164 }
165 
166 struct conf_printer {
167 	void (*print_symbol)(FILE *, struct symbol *, const char *, void *);
168 	void (*print_comment)(FILE *, const char *, void *);
169 };
170 
171 static void conf_warning(const char *fmt, ...)
172 	__attribute__ ((format (printf, 1, 2)));
173 
174 static void conf_message(const char *fmt, ...)
175 	__attribute__ ((format (printf, 1, 2)));
176 
177 static const char *conf_filename;
178 static int conf_lineno, conf_warnings;
179 
180 const char conf_defname[] = "arch/$(ARCH)/defconfig";
181 
182 static void conf_warning(const char *fmt, ...)
183 {
184 	va_list ap;
185 	va_start(ap, fmt);
186 	fprintf(stderr, "%s:%d:warning: ", conf_filename, conf_lineno);
187 	vfprintf(stderr, fmt, ap);
188 	fprintf(stderr, "\n");
189 	va_end(ap);
190 	conf_warnings++;
191 }
192 
193 static void conf_default_message_callback(const char *s)
194 {
195 	printf("#\n# ");
196 	printf("%s", s);
197 	printf("\n#\n");
198 }
199 
200 static void (*conf_message_callback)(const char *s) =
201 	conf_default_message_callback;
202 void conf_set_message_callback(void (*fn)(const char *s))
203 {
204 	conf_message_callback = fn;
205 }
206 
207 static void conf_message(const char *fmt, ...)
208 {
209 	va_list ap;
210 	char buf[4096];
211 
212 	if (!conf_message_callback)
213 		return;
214 
215 	va_start(ap, fmt);
216 
217 	vsnprintf(buf, sizeof(buf), fmt, ap);
218 	conf_message_callback(buf);
219 	va_end(ap);
220 }
221 
222 const char *conf_get_configname(void)
223 {
224 	char *name = getenv("KCONFIG_CONFIG");
225 
226 	return name ? name : ".config";
227 }
228 
229 static const char *conf_get_autoconfig_name(void)
230 {
231 	char *name = getenv("KCONFIG_AUTOCONFIG");
232 
233 	return name ? name : "include/config/auto.conf";
234 }
235 
236 char *conf_get_default_confname(void)
237 {
238 	static char fullname[PATH_MAX+1];
239 	char *env, *name;
240 
241 	name = expand_string(conf_defname);
242 	env = getenv(SRCTREE);
243 	if (env) {
244 		snprintf(fullname, sizeof(fullname), "%s/%s", env, name);
245 		if (is_present(fullname))
246 			return fullname;
247 	}
248 	return name;
249 }
250 
251 static int conf_set_sym_val(struct symbol *sym, int def, int def_flags, char *p)
252 {
253 	char *p2;
254 
255 	switch (sym->type) {
256 	case S_TRISTATE:
257 		if (p[0] == 'm') {
258 			sym->def[def].tri = mod;
259 			sym->flags |= def_flags;
260 			break;
261 		}
262 		/* fall through */
263 	case S_BOOLEAN:
264 		if (p[0] == 'y') {
265 			sym->def[def].tri = yes;
266 			sym->flags |= def_flags;
267 			break;
268 		}
269 		if (p[0] == 'n') {
270 			sym->def[def].tri = no;
271 			sym->flags |= def_flags;
272 			break;
273 		}
274 		if (def != S_DEF_AUTO)
275 			conf_warning("symbol value '%s' invalid for %s",
276 				     p, sym->name);
277 		return 1;
278 	case S_STRING:
279 		if (*p++ != '"')
280 			break;
281 		for (p2 = p; (p2 = strpbrk(p2, "\"\\")); p2++) {
282 			if (*p2 == '"') {
283 				*p2 = 0;
284 				break;
285 			}
286 			memmove(p2, p2 + 1, strlen(p2));
287 		}
288 		if (!p2) {
289 			if (def != S_DEF_AUTO)
290 				conf_warning("invalid string found");
291 			return 1;
292 		}
293 		/* fall through */
294 	case S_INT:
295 	case S_HEX:
296 		if (sym_string_valid(sym, p)) {
297 			sym->def[def].val = xstrdup(p);
298 			sym->flags |= def_flags;
299 		} else {
300 			if (def != S_DEF_AUTO)
301 				conf_warning("symbol value '%s' invalid for %s",
302 					     p, sym->name);
303 			return 1;
304 		}
305 		break;
306 	default:
307 		;
308 	}
309 	return 0;
310 }
311 
312 #define LINE_GROWTH 16
313 static int add_byte(int c, char **lineptr, size_t slen, size_t *n)
314 {
315 	char *nline;
316 	size_t new_size = slen + 1;
317 	if (new_size > *n) {
318 		new_size += LINE_GROWTH - 1;
319 		new_size *= 2;
320 		nline = xrealloc(*lineptr, new_size);
321 		if (!nline)
322 			return -1;
323 
324 		*lineptr = nline;
325 		*n = new_size;
326 	}
327 
328 	(*lineptr)[slen] = c;
329 
330 	return 0;
331 }
332 
333 static ssize_t compat_getline(char **lineptr, size_t *n, FILE *stream)
334 {
335 	char *line = *lineptr;
336 	size_t slen = 0;
337 
338 	for (;;) {
339 		int c = getc(stream);
340 
341 		switch (c) {
342 		case '\n':
343 			if (add_byte(c, &line, slen, n) < 0)
344 				goto e_out;
345 			slen++;
346 			/* fall through */
347 		case EOF:
348 			if (add_byte('\0', &line, slen, n) < 0)
349 				goto e_out;
350 			*lineptr = line;
351 			if (slen == 0)
352 				return -1;
353 			return slen;
354 		default:
355 			if (add_byte(c, &line, slen, n) < 0)
356 				goto e_out;
357 			slen++;
358 		}
359 	}
360 
361 e_out:
362 	line[slen-1] = '\0';
363 	*lineptr = line;
364 	return -1;
365 }
366 
367 int conf_read_simple(const char *name, int def)
368 {
369 	FILE *in = NULL;
370 	char   *line = NULL;
371 	size_t  line_asize = 0;
372 	char *p, *p2;
373 	struct symbol *sym;
374 	int i, def_flags;
375 
376 	if (name) {
377 		in = zconf_fopen(name);
378 	} else {
379 		struct property *prop;
380 
381 		name = conf_get_configname();
382 		in = zconf_fopen(name);
383 		if (in)
384 			goto load;
385 		sym_add_change_count(1);
386 		if (!sym_defconfig_list)
387 			return 1;
388 
389 		for_all_defaults(sym_defconfig_list, prop) {
390 			if (expr_calc_value(prop->visible.expr) == no ||
391 			    prop->expr->type != E_SYMBOL)
392 				continue;
393 			sym_calc_value(prop->expr->left.sym);
394 			name = sym_get_string_value(prop->expr->left.sym);
395 			in = zconf_fopen(name);
396 			if (in) {
397 				conf_message("using defaults found in %s",
398 					 name);
399 				goto load;
400 			}
401 		}
402 	}
403 	if (!in)
404 		return 1;
405 
406 load:
407 	conf_filename = name;
408 	conf_lineno = 0;
409 	conf_warnings = 0;
410 
411 	def_flags = SYMBOL_DEF << def;
412 	for_all_symbols(i, sym) {
413 		sym->flags |= SYMBOL_CHANGED;
414 		sym->flags &= ~(def_flags|SYMBOL_VALID);
415 		if (sym_is_choice(sym))
416 			sym->flags |= def_flags;
417 		switch (sym->type) {
418 		case S_INT:
419 		case S_HEX:
420 		case S_STRING:
421 			if (sym->def[def].val)
422 				free(sym->def[def].val);
423 			/* fall through */
424 		default:
425 			sym->def[def].val = NULL;
426 			sym->def[def].tri = no;
427 		}
428 	}
429 
430 	while (compat_getline(&line, &line_asize, in) != -1) {
431 		conf_lineno++;
432 		sym = NULL;
433 		if (line[0] == '#') {
434 			if (memcmp(line + 2, CONFIG_, strlen(CONFIG_)))
435 				continue;
436 			p = strchr(line + 2 + strlen(CONFIG_), ' ');
437 			if (!p)
438 				continue;
439 			*p++ = 0;
440 			if (strncmp(p, "is not set", 10))
441 				continue;
442 			if (def == S_DEF_USER) {
443 				sym = sym_find(line + 2 + strlen(CONFIG_));
444 				if (!sym) {
445 					sym_add_change_count(1);
446 					continue;
447 				}
448 			} else {
449 				sym = sym_lookup(line + 2 + strlen(CONFIG_), 0);
450 				if (sym->type == S_UNKNOWN)
451 					sym->type = S_BOOLEAN;
452 			}
453 			if (sym->flags & def_flags) {
454 				conf_warning("override: reassigning to symbol %s", sym->name);
455 			}
456 			switch (sym->type) {
457 			case S_BOOLEAN:
458 			case S_TRISTATE:
459 				sym->def[def].tri = no;
460 				sym->flags |= def_flags;
461 				break;
462 			default:
463 				;
464 			}
465 		} else if (memcmp(line, CONFIG_, strlen(CONFIG_)) == 0) {
466 			p = strchr(line + strlen(CONFIG_), '=');
467 			if (!p)
468 				continue;
469 			*p++ = 0;
470 			p2 = strchr(p, '\n');
471 			if (p2) {
472 				*p2-- = 0;
473 				if (*p2 == '\r')
474 					*p2 = 0;
475 			}
476 
477 			sym = sym_find(line + strlen(CONFIG_));
478 			if (!sym) {
479 				if (def == S_DEF_AUTO)
480 					/*
481 					 * Reading from include/config/auto.conf
482 					 * If CONFIG_FOO previously existed in
483 					 * auto.conf but it is missing now,
484 					 * include/config/foo.h must be touched.
485 					 */
486 					conf_touch_dep(line + strlen(CONFIG_));
487 				else
488 					sym_add_change_count(1);
489 				continue;
490 			}
491 
492 			if (sym->flags & def_flags) {
493 				conf_warning("override: reassigning to symbol %s", sym->name);
494 			}
495 			if (conf_set_sym_val(sym, def, def_flags, p))
496 				continue;
497 		} else {
498 			if (line[0] != '\r' && line[0] != '\n')
499 				conf_warning("unexpected data: %.*s",
500 					     (int)strcspn(line, "\r\n"), line);
501 
502 			continue;
503 		}
504 
505 		if (sym && sym_is_choice_value(sym)) {
506 			struct symbol *cs = prop_get_symbol(sym_get_choice_prop(sym));
507 			switch (sym->def[def].tri) {
508 			case no:
509 				break;
510 			case mod:
511 				if (cs->def[def].tri == yes) {
512 					conf_warning("%s creates inconsistent choice state", sym->name);
513 					cs->flags &= ~def_flags;
514 				}
515 				break;
516 			case yes:
517 				if (cs->def[def].tri != no)
518 					conf_warning("override: %s changes choice state", sym->name);
519 				cs->def[def].val = sym;
520 				break;
521 			}
522 			cs->def[def].tri = EXPR_OR(cs->def[def].tri, sym->def[def].tri);
523 		}
524 	}
525 	free(line);
526 	fclose(in);
527 	return 0;
528 }
529 
530 int conf_read(const char *name)
531 {
532 	struct symbol *sym;
533 	int conf_unsaved = 0;
534 	int i;
535 
536 	sym_set_change_count(0);
537 
538 	if (conf_read_simple(name, S_DEF_USER)) {
539 		sym_calc_value(modules_sym);
540 		return 1;
541 	}
542 
543 	sym_calc_value(modules_sym);
544 
545 	for_all_symbols(i, sym) {
546 		sym_calc_value(sym);
547 		if (sym_is_choice(sym) || (sym->flags & SYMBOL_NO_WRITE))
548 			continue;
549 		if (sym_has_value(sym) && (sym->flags & SYMBOL_WRITE)) {
550 			/* check that calculated value agrees with saved value */
551 			switch (sym->type) {
552 			case S_BOOLEAN:
553 			case S_TRISTATE:
554 				if (sym->def[S_DEF_USER].tri != sym_get_tristate_value(sym))
555 					break;
556 				if (!sym_is_choice(sym))
557 					continue;
558 				/* fall through */
559 			default:
560 				if (!strcmp(sym->curr.val, sym->def[S_DEF_USER].val))
561 					continue;
562 				break;
563 			}
564 		} else if (!sym_has_value(sym) && !(sym->flags & SYMBOL_WRITE))
565 			/* no previous value and not saved */
566 			continue;
567 		conf_unsaved++;
568 		/* maybe print value in verbose mode... */
569 	}
570 
571 	for_all_symbols(i, sym) {
572 		if (sym_has_value(sym) && !sym_is_choice_value(sym)) {
573 			/* Reset values of generates values, so they'll appear
574 			 * as new, if they should become visible, but that
575 			 * doesn't quite work if the Kconfig and the saved
576 			 * configuration disagree.
577 			 */
578 			if (sym->visible == no && !conf_unsaved)
579 				sym->flags &= ~SYMBOL_DEF_USER;
580 			switch (sym->type) {
581 			case S_STRING:
582 			case S_INT:
583 			case S_HEX:
584 				/* Reset a string value if it's out of range */
585 				if (sym_string_within_range(sym, sym->def[S_DEF_USER].val))
586 					break;
587 				sym->flags &= ~(SYMBOL_VALID|SYMBOL_DEF_USER);
588 				conf_unsaved++;
589 				break;
590 			default:
591 				break;
592 			}
593 		}
594 	}
595 
596 	sym_add_change_count(conf_warnings || conf_unsaved);
597 
598 	return 0;
599 }
600 
601 /*
602  * Kconfig configuration printer
603  *
604  * This printer is used when generating the resulting configuration after
605  * kconfig invocation and `defconfig' files. Unset symbol might be omitted by
606  * passing a non-NULL argument to the printer.
607  *
608  */
609 static void
610 kconfig_print_symbol(FILE *fp, struct symbol *sym, const char *value, void *arg)
611 {
612 
613 	switch (sym->type) {
614 	case S_BOOLEAN:
615 	case S_TRISTATE:
616 		if (*value == 'n') {
617 			bool skip_unset = (arg != NULL);
618 
619 			if (!skip_unset)
620 				fprintf(fp, "# %s%s is not set\n",
621 				    CONFIG_, sym->name);
622 			return;
623 		}
624 		break;
625 	default:
626 		break;
627 	}
628 
629 	fprintf(fp, "%s%s=%s\n", CONFIG_, sym->name, value);
630 }
631 
632 static void
633 kconfig_print_comment(FILE *fp, const char *value, void *arg)
634 {
635 	const char *p = value;
636 	size_t l;
637 
638 	for (;;) {
639 		l = strcspn(p, "\n");
640 		fprintf(fp, "#");
641 		if (l) {
642 			fprintf(fp, " ");
643 			xfwrite(p, l, 1, fp);
644 			p += l;
645 		}
646 		fprintf(fp, "\n");
647 		if (*p++ == '\0')
648 			break;
649 	}
650 }
651 
652 static struct conf_printer kconfig_printer_cb =
653 {
654 	.print_symbol = kconfig_print_symbol,
655 	.print_comment = kconfig_print_comment,
656 };
657 
658 /*
659  * Header printer
660  *
661  * This printer is used when generating the `include/generated/autoconf.h' file.
662  */
663 static void
664 header_print_symbol(FILE *fp, struct symbol *sym, const char *value, void *arg)
665 {
666 
667 	switch (sym->type) {
668 	case S_BOOLEAN:
669 	case S_TRISTATE: {
670 		const char *suffix = "";
671 
672 		switch (*value) {
673 		case 'n':
674 			break;
675 		case 'm':
676 			suffix = "_MODULE";
677 			/* fall through */
678 		default:
679 			fprintf(fp, "#define %s%s%s 1\n",
680 			    CONFIG_, sym->name, suffix);
681 		}
682 		break;
683 	}
684 	case S_HEX: {
685 		const char *prefix = "";
686 
687 		if (value[0] != '0' || (value[1] != 'x' && value[1] != 'X'))
688 			prefix = "0x";
689 		fprintf(fp, "#define %s%s %s%s\n",
690 		    CONFIG_, sym->name, prefix, value);
691 		break;
692 	}
693 	case S_STRING:
694 	case S_INT:
695 		fprintf(fp, "#define %s%s %s\n",
696 		    CONFIG_, sym->name, value);
697 		break;
698 	default:
699 		break;
700 	}
701 
702 }
703 
704 static void
705 header_print_comment(FILE *fp, const char *value, void *arg)
706 {
707 	const char *p = value;
708 	size_t l;
709 
710 	fprintf(fp, "/*\n");
711 	for (;;) {
712 		l = strcspn(p, "\n");
713 		fprintf(fp, " *");
714 		if (l) {
715 			fprintf(fp, " ");
716 			xfwrite(p, l, 1, fp);
717 			p += l;
718 		}
719 		fprintf(fp, "\n");
720 		if (*p++ == '\0')
721 			break;
722 	}
723 	fprintf(fp, " */\n");
724 }
725 
726 static struct conf_printer header_printer_cb =
727 {
728 	.print_symbol = header_print_symbol,
729 	.print_comment = header_print_comment,
730 };
731 
732 /*
733  * Tristate printer
734  *
735  * This printer is used when generating the `include/config/tristate.conf' file.
736  */
737 static void
738 tristate_print_symbol(FILE *fp, struct symbol *sym, const char *value, void *arg)
739 {
740 
741 	if (sym->type == S_TRISTATE && *value != 'n')
742 		fprintf(fp, "%s%s=%c\n", CONFIG_, sym->name, (char)toupper(*value));
743 }
744 
745 static struct conf_printer tristate_printer_cb =
746 {
747 	.print_symbol = tristate_print_symbol,
748 	.print_comment = kconfig_print_comment,
749 };
750 
751 static void conf_write_symbol(FILE *fp, struct symbol *sym,
752 			      struct conf_printer *printer, void *printer_arg)
753 {
754 	const char *str;
755 
756 	switch (sym->type) {
757 	case S_UNKNOWN:
758 		break;
759 	case S_STRING:
760 		str = sym_get_string_value(sym);
761 		str = sym_escape_string_value(str);
762 		printer->print_symbol(fp, sym, str, printer_arg);
763 		free((void *)str);
764 		break;
765 	default:
766 		str = sym_get_string_value(sym);
767 		printer->print_symbol(fp, sym, str, printer_arg);
768 	}
769 }
770 
771 static void
772 conf_write_heading(FILE *fp, struct conf_printer *printer, void *printer_arg)
773 {
774 	char buf[256];
775 
776 	snprintf(buf, sizeof(buf),
777 	    "\n"
778 	    "Automatically generated file; DO NOT EDIT.\n"
779 	    "%s\n",
780 	    rootmenu.prompt->text);
781 
782 	printer->print_comment(fp, buf, printer_arg);
783 }
784 
785 /*
786  * Write out a minimal config.
787  * All values that has default values are skipped as this is redundant.
788  */
789 int conf_write_defconfig(const char *filename)
790 {
791 	struct symbol *sym;
792 	struct menu *menu;
793 	FILE *out;
794 
795 	out = fopen(filename, "w");
796 	if (!out)
797 		return 1;
798 
799 	sym_clear_all_valid();
800 
801 	/* Traverse all menus to find all relevant symbols */
802 	menu = rootmenu.list;
803 
804 	while (menu != NULL)
805 	{
806 		sym = menu->sym;
807 		if (sym == NULL) {
808 			if (!menu_is_visible(menu))
809 				goto next_menu;
810 		} else if (!sym_is_choice(sym)) {
811 			sym_calc_value(sym);
812 			if (!(sym->flags & SYMBOL_WRITE))
813 				goto next_menu;
814 			sym->flags &= ~SYMBOL_WRITE;
815 			/* If we cannot change the symbol - skip */
816 			if (!sym_is_changable(sym))
817 				goto next_menu;
818 			/* If symbol equals to default value - skip */
819 			if (strcmp(sym_get_string_value(sym), sym_get_string_default(sym)) == 0)
820 				goto next_menu;
821 
822 			/*
823 			 * If symbol is a choice value and equals to the
824 			 * default for a choice - skip.
825 			 * But only if value is bool and equal to "y" and
826 			 * choice is not "optional".
827 			 * (If choice is "optional" then all values can be "n")
828 			 */
829 			if (sym_is_choice_value(sym)) {
830 				struct symbol *cs;
831 				struct symbol *ds;
832 
833 				cs = prop_get_symbol(sym_get_choice_prop(sym));
834 				ds = sym_choice_default(cs);
835 				if (!sym_is_optional(cs) && sym == ds) {
836 					if ((sym->type == S_BOOLEAN) &&
837 					    sym_get_tristate_value(sym) == yes)
838 						goto next_menu;
839 				}
840 			}
841 			conf_write_symbol(out, sym, &kconfig_printer_cb, NULL);
842 		}
843 next_menu:
844 		if (menu->list != NULL) {
845 			menu = menu->list;
846 		}
847 		else if (menu->next != NULL) {
848 			menu = menu->next;
849 		} else {
850 			while ((menu = menu->parent)) {
851 				if (menu->next != NULL) {
852 					menu = menu->next;
853 					break;
854 				}
855 			}
856 		}
857 	}
858 	fclose(out);
859 	return 0;
860 }
861 
862 int conf_write(const char *name)
863 {
864 	FILE *out;
865 	struct symbol *sym;
866 	struct menu *menu;
867 	const char *str;
868 	char tmpname[PATH_MAX + 1], oldname[PATH_MAX + 1];
869 	char *env;
870 	bool need_newline = false;
871 
872 	if (!name)
873 		name = conf_get_configname();
874 
875 	if (!*name) {
876 		fprintf(stderr, "config name is empty\n");
877 		return -1;
878 	}
879 
880 	if (is_dir(name)) {
881 		fprintf(stderr, "%s: Is a directory\n", name);
882 		return -1;
883 	}
884 
885 	if (make_parent_dir(name))
886 		return -1;
887 
888 	env = getenv("KCONFIG_OVERWRITECONFIG");
889 	if (env && *env) {
890 		*tmpname = 0;
891 		out = fopen(name, "w");
892 	} else {
893 		snprintf(tmpname, sizeof(tmpname), "%s.%d.tmp",
894 			 name, (int)getpid());
895 		out = fopen(tmpname, "w");
896 	}
897 	if (!out)
898 		return 1;
899 
900 	conf_write_heading(out, &kconfig_printer_cb, NULL);
901 
902 	if (!conf_get_changed())
903 		sym_clear_all_valid();
904 
905 	menu = rootmenu.list;
906 	while (menu) {
907 		sym = menu->sym;
908 		if (!sym) {
909 			if (!menu_is_visible(menu))
910 				goto next;
911 			str = menu_get_prompt(menu);
912 			fprintf(out, "\n"
913 				     "#\n"
914 				     "# %s\n"
915 				     "#\n", str);
916 			need_newline = false;
917 		} else if (!(sym->flags & SYMBOL_CHOICE)) {
918 			sym_calc_value(sym);
919 			if (!(sym->flags & SYMBOL_WRITE))
920 				goto next;
921 			if (need_newline) {
922 				fprintf(out, "\n");
923 				need_newline = false;
924 			}
925 			sym->flags &= ~SYMBOL_WRITE;
926 			conf_write_symbol(out, sym, &kconfig_printer_cb, NULL);
927 		}
928 
929 next:
930 		if (menu->list) {
931 			menu = menu->list;
932 			continue;
933 		}
934 		if (menu->next)
935 			menu = menu->next;
936 		else while ((menu = menu->parent)) {
937 			if (!menu->sym && menu_is_visible(menu) &&
938 			    menu != &rootmenu) {
939 				str = menu_get_prompt(menu);
940 				fprintf(out, "# end of %s\n", str);
941 				need_newline = true;
942 			}
943 			if (menu->next) {
944 				menu = menu->next;
945 				break;
946 			}
947 		}
948 	}
949 	fclose(out);
950 
951 	if (*tmpname) {
952 		if (is_same(name, tmpname)) {
953 			conf_message("No change to %s", name);
954 			unlink(tmpname);
955 			sym_set_change_count(0);
956 			return 0;
957 		}
958 
959 		snprintf(oldname, sizeof(oldname), "%s.old", name);
960 		rename(name, oldname);
961 		if (rename(tmpname, name))
962 			return 1;
963 	}
964 
965 	conf_message("configuration written to %s", name);
966 
967 	sym_set_change_count(0);
968 
969 	return 0;
970 }
971 
972 /* write a dependency file as used by kbuild to track dependencies */
973 static int conf_write_dep(const char *name)
974 {
975 	struct file *file;
976 	FILE *out;
977 
978 	out = fopen("..config.tmp", "w");
979 	if (!out)
980 		return 1;
981 	fprintf(out, "deps_config := \\\n");
982 	for (file = file_list; file; file = file->next) {
983 		if (file->next)
984 			fprintf(out, "\t%s \\\n", file->name);
985 		else
986 			fprintf(out, "\t%s\n", file->name);
987 	}
988 	fprintf(out, "\n%s: \\\n"
989 		     "\t$(deps_config)\n\n", conf_get_autoconfig_name());
990 
991 	env_write_dep(out, conf_get_autoconfig_name());
992 
993 	fprintf(out, "\n$(deps_config): ;\n");
994 	fclose(out);
995 
996 	if (make_parent_dir(name))
997 		return 1;
998 	rename("..config.tmp", name);
999 	return 0;
1000 }
1001 
1002 static int conf_touch_deps(void)
1003 {
1004 	const char *name;
1005 	struct symbol *sym;
1006 	int res, i;
1007 
1008 	strcpy(depfile_path, "include/config/");
1009 	depfile_prefix_len = strlen(depfile_path);
1010 
1011 	name = conf_get_autoconfig_name();
1012 	conf_read_simple(name, S_DEF_AUTO);
1013 	sym_calc_value(modules_sym);
1014 
1015 	for_all_symbols(i, sym) {
1016 		sym_calc_value(sym);
1017 		if ((sym->flags & SYMBOL_NO_WRITE) || !sym->name)
1018 			continue;
1019 		if (sym->flags & SYMBOL_WRITE) {
1020 			if (sym->flags & SYMBOL_DEF_AUTO) {
1021 				/*
1022 				 * symbol has old and new value,
1023 				 * so compare them...
1024 				 */
1025 				switch (sym->type) {
1026 				case S_BOOLEAN:
1027 				case S_TRISTATE:
1028 					if (sym_get_tristate_value(sym) ==
1029 					    sym->def[S_DEF_AUTO].tri)
1030 						continue;
1031 					break;
1032 				case S_STRING:
1033 				case S_HEX:
1034 				case S_INT:
1035 					if (!strcmp(sym_get_string_value(sym),
1036 						    sym->def[S_DEF_AUTO].val))
1037 						continue;
1038 					break;
1039 				default:
1040 					break;
1041 				}
1042 			} else {
1043 				/*
1044 				 * If there is no old value, only 'no' (unset)
1045 				 * is allowed as new value.
1046 				 */
1047 				switch (sym->type) {
1048 				case S_BOOLEAN:
1049 				case S_TRISTATE:
1050 					if (sym_get_tristate_value(sym) == no)
1051 						continue;
1052 					break;
1053 				default:
1054 					break;
1055 				}
1056 			}
1057 		} else if (!(sym->flags & SYMBOL_DEF_AUTO))
1058 			/* There is neither an old nor a new value. */
1059 			continue;
1060 		/* else
1061 		 *	There is an old value, but no new value ('no' (unset)
1062 		 *	isn't saved in auto.conf, so the old value is always
1063 		 *	different from 'no').
1064 		 */
1065 
1066 		res = conf_touch_dep(sym->name);
1067 		if (res)
1068 			return res;
1069 	}
1070 
1071 	return 0;
1072 }
1073 
1074 int conf_write_autoconf(int overwrite)
1075 {
1076 	struct symbol *sym;
1077 	const char *name;
1078 	const char *autoconf_name = conf_get_autoconfig_name();
1079 	FILE *out, *tristate, *out_h;
1080 	int i;
1081 
1082 	if (!overwrite && is_present(autoconf_name))
1083 		return 0;
1084 
1085 	sym_clear_all_valid();
1086 
1087 	conf_write_dep("include/config/auto.conf.cmd");
1088 
1089 	if (conf_touch_deps())
1090 		return 1;
1091 
1092 	out = fopen(".tmpconfig", "w");
1093 	if (!out)
1094 		return 1;
1095 
1096 	tristate = fopen(".tmpconfig_tristate", "w");
1097 	if (!tristate) {
1098 		fclose(out);
1099 		return 1;
1100 	}
1101 
1102 	out_h = fopen(".tmpconfig.h", "w");
1103 	if (!out_h) {
1104 		fclose(out);
1105 		fclose(tristate);
1106 		return 1;
1107 	}
1108 
1109 	conf_write_heading(out, &kconfig_printer_cb, NULL);
1110 
1111 	conf_write_heading(tristate, &tristate_printer_cb, NULL);
1112 
1113 	conf_write_heading(out_h, &header_printer_cb, NULL);
1114 
1115 	for_all_symbols(i, sym) {
1116 		sym_calc_value(sym);
1117 		if (!(sym->flags & SYMBOL_WRITE) || !sym->name)
1118 			continue;
1119 
1120 		/* write symbol to auto.conf, tristate and header files */
1121 		conf_write_symbol(out, sym, &kconfig_printer_cb, (void *)1);
1122 
1123 		conf_write_symbol(tristate, sym, &tristate_printer_cb, (void *)1);
1124 
1125 		conf_write_symbol(out_h, sym, &header_printer_cb, NULL);
1126 	}
1127 	fclose(out);
1128 	fclose(tristate);
1129 	fclose(out_h);
1130 
1131 	name = getenv("KCONFIG_AUTOHEADER");
1132 	if (!name)
1133 		name = "include/generated/autoconf.h";
1134 	if (make_parent_dir(name))
1135 		return 1;
1136 	if (rename(".tmpconfig.h", name))
1137 		return 1;
1138 
1139 	name = getenv("KCONFIG_TRISTATE");
1140 	if (!name)
1141 		name = "include/config/tristate.conf";
1142 	if (make_parent_dir(name))
1143 		return 1;
1144 	if (rename(".tmpconfig_tristate", name))
1145 		return 1;
1146 
1147 	if (make_parent_dir(autoconf_name))
1148 		return 1;
1149 	/*
1150 	 * This must be the last step, kbuild has a dependency on auto.conf
1151 	 * and this marks the successful completion of the previous steps.
1152 	 */
1153 	if (rename(".tmpconfig", autoconf_name))
1154 		return 1;
1155 
1156 	return 0;
1157 }
1158 
1159 static int sym_change_count;
1160 static void (*conf_changed_callback)(void);
1161 
1162 void sym_set_change_count(int count)
1163 {
1164 	int _sym_change_count = sym_change_count;
1165 	sym_change_count = count;
1166 	if (conf_changed_callback &&
1167 	    (bool)_sym_change_count != (bool)count)
1168 		conf_changed_callback();
1169 }
1170 
1171 void sym_add_change_count(int count)
1172 {
1173 	sym_set_change_count(count + sym_change_count);
1174 }
1175 
1176 bool conf_get_changed(void)
1177 {
1178 	return sym_change_count;
1179 }
1180 
1181 void conf_set_changed_callback(void (*fn)(void))
1182 {
1183 	conf_changed_callback = fn;
1184 }
1185 
1186 static bool randomize_choice_values(struct symbol *csym)
1187 {
1188 	struct property *prop;
1189 	struct symbol *sym;
1190 	struct expr *e;
1191 	int cnt, def;
1192 
1193 	/*
1194 	 * If choice is mod then we may have more items selected
1195 	 * and if no then no-one.
1196 	 * In both cases stop.
1197 	 */
1198 	if (csym->curr.tri != yes)
1199 		return false;
1200 
1201 	prop = sym_get_choice_prop(csym);
1202 
1203 	/* count entries in choice block */
1204 	cnt = 0;
1205 	expr_list_for_each_sym(prop->expr, e, sym)
1206 		cnt++;
1207 
1208 	/*
1209 	 * find a random value and set it to yes,
1210 	 * set the rest to no so we have only one set
1211 	 */
1212 	def = (rand() % cnt);
1213 
1214 	cnt = 0;
1215 	expr_list_for_each_sym(prop->expr, e, sym) {
1216 		if (def == cnt++) {
1217 			sym->def[S_DEF_USER].tri = yes;
1218 			csym->def[S_DEF_USER].val = sym;
1219 		}
1220 		else {
1221 			sym->def[S_DEF_USER].tri = no;
1222 		}
1223 		sym->flags |= SYMBOL_DEF_USER;
1224 		/* clear VALID to get value calculated */
1225 		sym->flags &= ~SYMBOL_VALID;
1226 	}
1227 	csym->flags |= SYMBOL_DEF_USER;
1228 	/* clear VALID to get value calculated */
1229 	csym->flags &= ~(SYMBOL_VALID);
1230 
1231 	return true;
1232 }
1233 
1234 void set_all_choice_values(struct symbol *csym)
1235 {
1236 	struct property *prop;
1237 	struct symbol *sym;
1238 	struct expr *e;
1239 
1240 	prop = sym_get_choice_prop(csym);
1241 
1242 	/*
1243 	 * Set all non-assinged choice values to no
1244 	 */
1245 	expr_list_for_each_sym(prop->expr, e, sym) {
1246 		if (!sym_has_value(sym))
1247 			sym->def[S_DEF_USER].tri = no;
1248 	}
1249 	csym->flags |= SYMBOL_DEF_USER;
1250 	/* clear VALID to get value calculated */
1251 	csym->flags &= ~(SYMBOL_VALID | SYMBOL_NEED_SET_CHOICE_VALUES);
1252 }
1253 
1254 bool conf_set_all_new_symbols(enum conf_def_mode mode)
1255 {
1256 	struct symbol *sym, *csym;
1257 	int i, cnt, pby, pty, ptm;	/* pby: probability of bool     = y
1258 					 * pty: probability of tristate = y
1259 					 * ptm: probability of tristate = m
1260 					 */
1261 
1262 	pby = 50; pty = ptm = 33; /* can't go as the default in switch-case
1263 				   * below, otherwise gcc whines about
1264 				   * -Wmaybe-uninitialized */
1265 	if (mode == def_random) {
1266 		int n, p[3];
1267 		char *env = getenv("KCONFIG_PROBABILITY");
1268 		n = 0;
1269 		while( env && *env ) {
1270 			char *endp;
1271 			int tmp = strtol( env, &endp, 10 );
1272 			if( tmp >= 0 && tmp <= 100 ) {
1273 				p[n++] = tmp;
1274 			} else {
1275 				errno = ERANGE;
1276 				perror( "KCONFIG_PROBABILITY" );
1277 				exit( 1 );
1278 			}
1279 			env = (*endp == ':') ? endp+1 : endp;
1280 			if( n >=3 ) {
1281 				break;
1282 			}
1283 		}
1284 		switch( n ) {
1285 		case 1:
1286 			pby = p[0]; ptm = pby/2; pty = pby-ptm;
1287 			break;
1288 		case 2:
1289 			pty = p[0]; ptm = p[1]; pby = pty + ptm;
1290 			break;
1291 		case 3:
1292 			pby = p[0]; pty = p[1]; ptm = p[2];
1293 			break;
1294 		}
1295 
1296 		if( pty+ptm > 100 ) {
1297 			errno = ERANGE;
1298 			perror( "KCONFIG_PROBABILITY" );
1299 			exit( 1 );
1300 		}
1301 	}
1302 	bool has_changed = false;
1303 
1304 	for_all_symbols(i, sym) {
1305 		if (sym_has_value(sym) || (sym->flags & SYMBOL_VALID))
1306 			continue;
1307 		switch (sym_get_type(sym)) {
1308 		case S_BOOLEAN:
1309 		case S_TRISTATE:
1310 			has_changed = true;
1311 			switch (mode) {
1312 			case def_yes:
1313 				sym->def[S_DEF_USER].tri = yes;
1314 				break;
1315 			case def_mod:
1316 				sym->def[S_DEF_USER].tri = mod;
1317 				break;
1318 			case def_no:
1319 				if (sym->flags & SYMBOL_ALLNOCONFIG_Y)
1320 					sym->def[S_DEF_USER].tri = yes;
1321 				else
1322 					sym->def[S_DEF_USER].tri = no;
1323 				break;
1324 			case def_random:
1325 				sym->def[S_DEF_USER].tri = no;
1326 				cnt = rand() % 100;
1327 				if (sym->type == S_TRISTATE) {
1328 					if (cnt < pty)
1329 						sym->def[S_DEF_USER].tri = yes;
1330 					else if (cnt < (pty+ptm))
1331 						sym->def[S_DEF_USER].tri = mod;
1332 				} else if (cnt < pby)
1333 					sym->def[S_DEF_USER].tri = yes;
1334 				break;
1335 			default:
1336 				continue;
1337 			}
1338 			if (!(sym_is_choice(sym) && mode == def_random))
1339 				sym->flags |= SYMBOL_DEF_USER;
1340 			break;
1341 		default:
1342 			break;
1343 		}
1344 
1345 	}
1346 
1347 	sym_clear_all_valid();
1348 
1349 	/*
1350 	 * We have different type of choice blocks.
1351 	 * If curr.tri equals to mod then we can select several
1352 	 * choice symbols in one block.
1353 	 * In this case we do nothing.
1354 	 * If curr.tri equals yes then only one symbol can be
1355 	 * selected in a choice block and we set it to yes,
1356 	 * and the rest to no.
1357 	 */
1358 	if (mode != def_random) {
1359 		for_all_symbols(i, csym) {
1360 			if ((sym_is_choice(csym) && !sym_has_value(csym)) ||
1361 			    sym_is_choice_value(csym))
1362 				csym->flags |= SYMBOL_NEED_SET_CHOICE_VALUES;
1363 		}
1364 	}
1365 
1366 	for_all_symbols(i, csym) {
1367 		if (sym_has_value(csym) || !sym_is_choice(csym))
1368 			continue;
1369 
1370 		sym_calc_value(csym);
1371 		if (mode == def_random)
1372 			has_changed = randomize_choice_values(csym);
1373 		else {
1374 			set_all_choice_values(csym);
1375 			has_changed = true;
1376 		}
1377 	}
1378 
1379 	return has_changed;
1380 }
1381