xref: /linux/scripts/kconfig/symbol.c (revision 8832266dae4f4b401fedce537448bf0cda233b1a) 
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (C) 2002 Roman Zippel <zippel@linux-m68k.org>
4  */
5 
6 #include <sys/types.h>
7 #include <ctype.h>
8 #include <stdlib.h>
9 #include <string.h>
10 #include <regex.h>
11 
12 #include "internal.h"
13 #include "lkc.h"
14 
15 struct symbol symbol_yes = {
16 	.name = "y",
17 	.type = S_TRISTATE,
18 	.curr = { "y", yes },
19 	.menus = LIST_HEAD_INIT(symbol_yes.menus),
20 	.flags = SYMBOL_CONST|SYMBOL_VALID,
21 };
22 
23 struct symbol symbol_mod = {
24 	.name = "m",
25 	.type = S_TRISTATE,
26 	.curr = { "m", mod },
27 	.menus = LIST_HEAD_INIT(symbol_mod.menus),
28 	.flags = SYMBOL_CONST|SYMBOL_VALID,
29 };
30 
31 struct symbol symbol_no = {
32 	.name = "n",
33 	.type = S_TRISTATE,
34 	.curr = { "n", no },
35 	.menus = LIST_HEAD_INIT(symbol_no.menus),
36 	.flags = SYMBOL_CONST|SYMBOL_VALID,
37 };
38 
39 struct symbol *modules_sym;
40 static tristate modules_val;
41 static int sym_warnings;
42 
43 enum symbol_type sym_get_type(struct symbol *sym)
44 {
45 	enum symbol_type type = sym->type;
46 
47 	if (type == S_TRISTATE) {
48 		if (sym_is_choice_value(sym) && sym->visible == yes)
49 			type = S_BOOLEAN;
50 		else if (modules_val == no)
51 			type = S_BOOLEAN;
52 	}
53 	return type;
54 }
55 
56 const char *sym_type_name(enum symbol_type type)
57 {
58 	switch (type) {
59 	case S_BOOLEAN:
60 		return "bool";
61 	case S_TRISTATE:
62 		return "tristate";
63 	case S_INT:
64 		return "integer";
65 	case S_HEX:
66 		return "hex";
67 	case S_STRING:
68 		return "string";
69 	case S_UNKNOWN:
70 		return "unknown";
71 	}
72 	return "???";
73 }
74 
75 struct property *sym_get_choice_prop(struct symbol *sym)
76 {
77 	struct property *prop;
78 
79 	for_all_choices(sym, prop)
80 		return prop;
81 	return NULL;
82 }
83 
84 /**
85  * sym_get_choice_menu - get the parent choice menu if present
86  *
87  * @sym: a symbol pointer
88  *
89  * Return: a choice menu if this function is called against a choice member.
90  */
91 struct menu *sym_get_choice_menu(struct symbol *sym)
92 {
93 	struct menu *menu = NULL;
94 	struct menu *m;
95 
96 	/*
97 	 * Choice members must have a prompt. Find a menu entry with a prompt,
98 	 * and assume it resides inside a choice block.
99 	 */
100 	list_for_each_entry(m, &sym->menus, link)
101 		if (m->prompt) {
102 			menu = m;
103 			break;
104 		}
105 
106 	if (!menu)
107 		return NULL;
108 
109 	do {
110 		menu = menu->parent;
111 	} while (menu && !menu->sym);
112 
113 	if (menu && menu->sym && sym_is_choice(menu->sym))
114 		return menu;
115 
116 	return NULL;
117 }
118 
119 static struct property *sym_get_default_prop(struct symbol *sym)
120 {
121 	struct property *prop;
122 
123 	for_all_defaults(sym, prop) {
124 		prop->visible.tri = expr_calc_value(prop->visible.expr);
125 		if (prop->visible.tri != no)
126 			return prop;
127 	}
128 	return NULL;
129 }
130 
131 struct property *sym_get_range_prop(struct symbol *sym)
132 {
133 	struct property *prop;
134 
135 	for_all_properties(sym, prop, P_RANGE) {
136 		prop->visible.tri = expr_calc_value(prop->visible.expr);
137 		if (prop->visible.tri != no)
138 			return prop;
139 	}
140 	return NULL;
141 }
142 
143 static long long sym_get_range_val(struct symbol *sym, int base)
144 {
145 	sym_calc_value(sym);
146 	switch (sym->type) {
147 	case S_INT:
148 		base = 10;
149 		break;
150 	case S_HEX:
151 		base = 16;
152 		break;
153 	default:
154 		break;
155 	}
156 	return strtoll(sym->curr.val, NULL, base);
157 }
158 
159 static void sym_validate_range(struct symbol *sym)
160 {
161 	struct property *prop;
162 	struct symbol *range_sym;
163 	int base;
164 	long long val, val2;
165 
166 	switch (sym->type) {
167 	case S_INT:
168 		base = 10;
169 		break;
170 	case S_HEX:
171 		base = 16;
172 		break;
173 	default:
174 		return;
175 	}
176 	prop = sym_get_range_prop(sym);
177 	if (!prop)
178 		return;
179 	val = strtoll(sym->curr.val, NULL, base);
180 	range_sym = prop->expr->left.sym;
181 	val2 = sym_get_range_val(range_sym, base);
182 	if (val >= val2) {
183 		range_sym = prop->expr->right.sym;
184 		val2 = sym_get_range_val(range_sym, base);
185 		if (val <= val2)
186 			return;
187 	}
188 	sym->curr.val = range_sym->curr.val;
189 }
190 
191 static void sym_set_changed(struct symbol *sym)
192 {
193 	struct menu *menu;
194 
195 	sym->flags |= SYMBOL_CHANGED;
196 	list_for_each_entry(menu, &sym->menus, link)
197 		menu->flags |= MENU_CHANGED;
198 }
199 
200 static void sym_set_all_changed(void)
201 {
202 	struct symbol *sym;
203 
204 	for_all_symbols(sym)
205 		sym_set_changed(sym);
206 }
207 
208 static void sym_calc_visibility(struct symbol *sym)
209 {
210 	struct property *prop;
211 	struct symbol *choice_sym = NULL;
212 	tristate tri;
213 
214 	/* any prompt visible? */
215 	tri = no;
216 
217 	if (sym_is_choice_value(sym))
218 		choice_sym = prop_get_symbol(sym_get_choice_prop(sym));
219 
220 	for_all_prompts(sym, prop) {
221 		prop->visible.tri = expr_calc_value(prop->visible.expr);
222 		/*
223 		 * Tristate choice_values with visibility 'mod' are
224 		 * not visible if the corresponding choice's value is
225 		 * 'yes'.
226 		 */
227 		if (choice_sym && sym->type == S_TRISTATE &&
228 		    prop->visible.tri == mod && choice_sym->curr.tri == yes)
229 			prop->visible.tri = no;
230 
231 		tri = EXPR_OR(tri, prop->visible.tri);
232 	}
233 	if (tri == mod && (sym->type != S_TRISTATE || modules_val == no))
234 		tri = yes;
235 	if (sym->visible != tri) {
236 		sym->visible = tri;
237 		sym_set_changed(sym);
238 	}
239 	if (sym_is_choice_value(sym))
240 		return;
241 	/* defaulting to "yes" if no explicit "depends on" are given */
242 	tri = yes;
243 	if (sym->dir_dep.expr)
244 		tri = expr_calc_value(sym->dir_dep.expr);
245 	if (tri == mod && sym_get_type(sym) == S_BOOLEAN)
246 		tri = yes;
247 	if (sym->dir_dep.tri != tri) {
248 		sym->dir_dep.tri = tri;
249 		sym_set_changed(sym);
250 	}
251 	tri = no;
252 	if (sym->rev_dep.expr)
253 		tri = expr_calc_value(sym->rev_dep.expr);
254 	if (tri == mod && sym_get_type(sym) == S_BOOLEAN)
255 		tri = yes;
256 	if (sym->rev_dep.tri != tri) {
257 		sym->rev_dep.tri = tri;
258 		sym_set_changed(sym);
259 	}
260 	tri = no;
261 	if (sym->implied.expr)
262 		tri = expr_calc_value(sym->implied.expr);
263 	if (tri == mod && sym_get_type(sym) == S_BOOLEAN)
264 		tri = yes;
265 	if (sym->implied.tri != tri) {
266 		sym->implied.tri = tri;
267 		sym_set_changed(sym);
268 	}
269 }
270 
271 /*
272  * Find the default symbol for a choice.
273  * First try the default values for the choice symbol
274  * Next locate the first visible choice value
275  * Return NULL if none was found
276  */
277 struct symbol *sym_choice_default(struct symbol *sym)
278 {
279 	struct symbol *def_sym;
280 	struct property *prop;
281 	struct expr *e;
282 
283 	/* any of the defaults visible? */
284 	for_all_defaults(sym, prop) {
285 		prop->visible.tri = expr_calc_value(prop->visible.expr);
286 		if (prop->visible.tri == no)
287 			continue;
288 		def_sym = prop_get_symbol(prop);
289 		if (def_sym->visible != no)
290 			return def_sym;
291 	}
292 
293 	/* just get the first visible value */
294 	prop = sym_get_choice_prop(sym);
295 	expr_list_for_each_sym(prop->expr, e, def_sym)
296 		if (def_sym->visible != no)
297 			return def_sym;
298 
299 	/* failed to locate any defaults */
300 	return NULL;
301 }
302 
303 static struct symbol *sym_calc_choice(struct symbol *sym)
304 {
305 	struct symbol *def_sym;
306 	struct property *prop;
307 	struct expr *e;
308 	int flags;
309 
310 	/* first calculate all choice values' visibilities */
311 	flags = sym->flags;
312 	prop = sym_get_choice_prop(sym);
313 	expr_list_for_each_sym(prop->expr, e, def_sym) {
314 		sym_calc_visibility(def_sym);
315 		if (def_sym->visible != no)
316 			flags &= def_sym->flags;
317 	}
318 
319 	sym->flags &= flags | ~SYMBOL_DEF_USER;
320 
321 	/* is the user choice visible? */
322 	def_sym = sym->def[S_DEF_USER].val;
323 	if (def_sym && def_sym->visible != no)
324 		return def_sym;
325 
326 	def_sym = sym_choice_default(sym);
327 
328 	if (def_sym == NULL)
329 		/* no choice? reset tristate value */
330 		sym->curr.tri = no;
331 
332 	return def_sym;
333 }
334 
335 static void sym_warn_unmet_dep(struct symbol *sym)
336 {
337 	struct gstr gs = str_new();
338 
339 	str_printf(&gs,
340 		   "\nWARNING: unmet direct dependencies detected for %s\n",
341 		   sym->name);
342 	str_printf(&gs,
343 		   "  Depends on [%c]: ",
344 		   sym->dir_dep.tri == mod ? 'm' : 'n');
345 	expr_gstr_print(sym->dir_dep.expr, &gs);
346 	str_printf(&gs, "\n");
347 
348 	expr_gstr_print_revdep(sym->rev_dep.expr, &gs, yes,
349 			       "  Selected by [y]:\n");
350 	expr_gstr_print_revdep(sym->rev_dep.expr, &gs, mod,
351 			       "  Selected by [m]:\n");
352 
353 	fputs(str_get(&gs), stderr);
354 	sym_warnings++;
355 }
356 
357 bool sym_dep_errors(void)
358 {
359 	if (sym_warnings)
360 		return getenv("KCONFIG_WERROR");
361 	return false;
362 }
363 
364 void sym_calc_value(struct symbol *sym)
365 {
366 	struct symbol_value newval, oldval;
367 	struct property *prop;
368 	struct expr *e;
369 
370 	if (!sym)
371 		return;
372 
373 	if (sym->flags & SYMBOL_VALID)
374 		return;
375 
376 	if (sym_is_choice_value(sym) &&
377 	    sym->flags & SYMBOL_NEED_SET_CHOICE_VALUES) {
378 		sym->flags &= ~SYMBOL_NEED_SET_CHOICE_VALUES;
379 		prop = sym_get_choice_prop(sym);
380 		sym_calc_value(prop_get_symbol(prop));
381 	}
382 
383 	sym->flags |= SYMBOL_VALID;
384 
385 	oldval = sym->curr;
386 
387 	newval.tri = no;
388 
389 	switch (sym->type) {
390 	case S_INT:
391 		newval.val = "0";
392 		break;
393 	case S_HEX:
394 		newval.val = "0x0";
395 		break;
396 	case S_STRING:
397 		newval.val = "";
398 		break;
399 	case S_BOOLEAN:
400 	case S_TRISTATE:
401 		newval.val = "n";
402 		break;
403 	default:
404 		sym->curr.val = sym->name;
405 		sym->curr.tri = no;
406 		return;
407 	}
408 	sym->flags &= ~SYMBOL_WRITE;
409 
410 	sym_calc_visibility(sym);
411 
412 	if (sym->visible != no)
413 		sym->flags |= SYMBOL_WRITE;
414 
415 	/* set default if recursively called */
416 	sym->curr = newval;
417 
418 	switch (sym_get_type(sym)) {
419 	case S_BOOLEAN:
420 	case S_TRISTATE:
421 		if (sym_is_choice_value(sym) && sym->visible == yes) {
422 			prop = sym_get_choice_prop(sym);
423 			newval.tri = (prop_get_symbol(prop)->curr.val == sym) ? yes : no;
424 		} else {
425 			if (sym->visible != no) {
426 				/* if the symbol is visible use the user value
427 				 * if available, otherwise try the default value
428 				 */
429 				if (sym_has_value(sym)) {
430 					newval.tri = EXPR_AND(sym->def[S_DEF_USER].tri,
431 							      sym->visible);
432 					goto calc_newval;
433 				}
434 			}
435 			if (sym->rev_dep.tri != no)
436 				sym->flags |= SYMBOL_WRITE;
437 			if (!sym_is_choice(sym)) {
438 				prop = sym_get_default_prop(sym);
439 				if (prop) {
440 					newval.tri = EXPR_AND(expr_calc_value(prop->expr),
441 							      prop->visible.tri);
442 					if (newval.tri != no)
443 						sym->flags |= SYMBOL_WRITE;
444 				}
445 				if (sym->implied.tri != no) {
446 					sym->flags |= SYMBOL_WRITE;
447 					newval.tri = EXPR_OR(newval.tri, sym->implied.tri);
448 					newval.tri = EXPR_AND(newval.tri,
449 							      sym->dir_dep.tri);
450 				}
451 			}
452 		calc_newval:
453 			if (sym->dir_dep.tri < sym->rev_dep.tri)
454 				sym_warn_unmet_dep(sym);
455 			newval.tri = EXPR_OR(newval.tri, sym->rev_dep.tri);
456 		}
457 		if (newval.tri == mod && sym_get_type(sym) == S_BOOLEAN)
458 			newval.tri = yes;
459 		break;
460 	case S_STRING:
461 	case S_HEX:
462 	case S_INT:
463 		if (sym->visible != no && sym_has_value(sym)) {
464 			newval.val = sym->def[S_DEF_USER].val;
465 			break;
466 		}
467 		prop = sym_get_default_prop(sym);
468 		if (prop) {
469 			struct symbol *ds = prop_get_symbol(prop);
470 			if (ds) {
471 				sym->flags |= SYMBOL_WRITE;
472 				sym_calc_value(ds);
473 				newval.val = ds->curr.val;
474 			}
475 		}
476 		break;
477 	default:
478 		;
479 	}
480 
481 	sym->curr = newval;
482 	if (sym_is_choice(sym) && newval.tri == yes)
483 		sym->curr.val = sym_calc_choice(sym);
484 	sym_validate_range(sym);
485 
486 	if (memcmp(&oldval, &sym->curr, sizeof(oldval))) {
487 		sym_set_changed(sym);
488 		if (modules_sym == sym) {
489 			sym_set_all_changed();
490 			modules_val = modules_sym->curr.tri;
491 		}
492 	}
493 
494 	if (sym_is_choice(sym)) {
495 		struct symbol *choice_sym;
496 
497 		prop = sym_get_choice_prop(sym);
498 		expr_list_for_each_sym(prop->expr, e, choice_sym) {
499 			if ((sym->flags & SYMBOL_WRITE) &&
500 			    choice_sym->visible != no)
501 				choice_sym->flags |= SYMBOL_WRITE;
502 			if (sym->flags & SYMBOL_CHANGED)
503 				sym_set_changed(choice_sym);
504 		}
505 
506 		sym->flags &= ~SYMBOL_WRITE;
507 	}
508 
509 	if (sym->flags & SYMBOL_NEED_SET_CHOICE_VALUES)
510 		set_all_choice_values(sym);
511 }
512 
513 void sym_clear_all_valid(void)
514 {
515 	struct symbol *sym;
516 
517 	for_all_symbols(sym)
518 		sym->flags &= ~SYMBOL_VALID;
519 	conf_set_changed(true);
520 	sym_calc_value(modules_sym);
521 }
522 
523 bool sym_tristate_within_range(struct symbol *sym, tristate val)
524 {
525 	int type = sym_get_type(sym);
526 
527 	if (sym->visible == no)
528 		return false;
529 
530 	if (type != S_BOOLEAN && type != S_TRISTATE)
531 		return false;
532 
533 	if (type == S_BOOLEAN && val == mod)
534 		return false;
535 	if (sym->visible <= sym->rev_dep.tri)
536 		return false;
537 	if (sym_is_choice_value(sym) && sym->visible == yes)
538 		return val == yes;
539 	return val >= sym->rev_dep.tri && val <= sym->visible;
540 }
541 
542 bool sym_set_tristate_value(struct symbol *sym, tristate val)
543 {
544 	tristate oldval = sym_get_tristate_value(sym);
545 
546 	if (oldval != val && !sym_tristate_within_range(sym, val))
547 		return false;
548 
549 	if (!(sym->flags & SYMBOL_DEF_USER)) {
550 		sym->flags |= SYMBOL_DEF_USER;
551 		sym_set_changed(sym);
552 	}
553 	/*
554 	 * setting a choice value also resets the new flag of the choice
555 	 * symbol and all other choice values.
556 	 */
557 	if (sym_is_choice_value(sym) && val == yes) {
558 		struct symbol *cs = prop_get_symbol(sym_get_choice_prop(sym));
559 		struct property *prop;
560 		struct expr *e;
561 
562 		cs->def[S_DEF_USER].val = sym;
563 		cs->flags |= SYMBOL_DEF_USER;
564 		prop = sym_get_choice_prop(cs);
565 		for (e = prop->expr; e; e = e->left.expr) {
566 			if (e->right.sym->visible != no)
567 				e->right.sym->flags |= SYMBOL_DEF_USER;
568 		}
569 	}
570 
571 	sym->def[S_DEF_USER].tri = val;
572 	if (oldval != val)
573 		sym_clear_all_valid();
574 
575 	return true;
576 }
577 
578 tristate sym_toggle_tristate_value(struct symbol *sym)
579 {
580 	tristate oldval, newval;
581 
582 	oldval = newval = sym_get_tristate_value(sym);
583 	do {
584 		switch (newval) {
585 		case no:
586 			newval = mod;
587 			break;
588 		case mod:
589 			newval = yes;
590 			break;
591 		case yes:
592 			newval = no;
593 			break;
594 		}
595 		if (sym_set_tristate_value(sym, newval))
596 			break;
597 	} while (oldval != newval);
598 	return newval;
599 }
600 
601 bool sym_string_valid(struct symbol *sym, const char *str)
602 {
603 	signed char ch;
604 
605 	switch (sym->type) {
606 	case S_STRING:
607 		return true;
608 	case S_INT:
609 		ch = *str++;
610 		if (ch == '-')
611 			ch = *str++;
612 		if (!isdigit(ch))
613 			return false;
614 		if (ch == '0' && *str != 0)
615 			return false;
616 		while ((ch = *str++)) {
617 			if (!isdigit(ch))
618 				return false;
619 		}
620 		return true;
621 	case S_HEX:
622 		if (str[0] == '0' && (str[1] == 'x' || str[1] == 'X'))
623 			str += 2;
624 		ch = *str++;
625 		do {
626 			if (!isxdigit(ch))
627 				return false;
628 		} while ((ch = *str++));
629 		return true;
630 	case S_BOOLEAN:
631 	case S_TRISTATE:
632 		switch (str[0]) {
633 		case 'y': case 'Y':
634 		case 'm': case 'M':
635 		case 'n': case 'N':
636 			return true;
637 		}
638 		return false;
639 	default:
640 		return false;
641 	}
642 }
643 
644 bool sym_string_within_range(struct symbol *sym, const char *str)
645 {
646 	struct property *prop;
647 	long long val;
648 
649 	switch (sym->type) {
650 	case S_STRING:
651 		return sym_string_valid(sym, str);
652 	case S_INT:
653 		if (!sym_string_valid(sym, str))
654 			return false;
655 		prop = sym_get_range_prop(sym);
656 		if (!prop)
657 			return true;
658 		val = strtoll(str, NULL, 10);
659 		return val >= sym_get_range_val(prop->expr->left.sym, 10) &&
660 		       val <= sym_get_range_val(prop->expr->right.sym, 10);
661 	case S_HEX:
662 		if (!sym_string_valid(sym, str))
663 			return false;
664 		prop = sym_get_range_prop(sym);
665 		if (!prop)
666 			return true;
667 		val = strtoll(str, NULL, 16);
668 		return val >= sym_get_range_val(prop->expr->left.sym, 16) &&
669 		       val <= sym_get_range_val(prop->expr->right.sym, 16);
670 	case S_BOOLEAN:
671 	case S_TRISTATE:
672 		switch (str[0]) {
673 		case 'y': case 'Y':
674 			return sym_tristate_within_range(sym, yes);
675 		case 'm': case 'M':
676 			return sym_tristate_within_range(sym, mod);
677 		case 'n': case 'N':
678 			return sym_tristate_within_range(sym, no);
679 		}
680 		return false;
681 	default:
682 		return false;
683 	}
684 }
685 
686 bool sym_set_string_value(struct symbol *sym, const char *newval)
687 {
688 	const char *oldval;
689 	char *val;
690 	int size;
691 
692 	switch (sym->type) {
693 	case S_BOOLEAN:
694 	case S_TRISTATE:
695 		switch (newval[0]) {
696 		case 'y': case 'Y':
697 			return sym_set_tristate_value(sym, yes);
698 		case 'm': case 'M':
699 			return sym_set_tristate_value(sym, mod);
700 		case 'n': case 'N':
701 			return sym_set_tristate_value(sym, no);
702 		}
703 		return false;
704 	default:
705 		;
706 	}
707 
708 	if (!sym_string_within_range(sym, newval))
709 		return false;
710 
711 	if (!(sym->flags & SYMBOL_DEF_USER)) {
712 		sym->flags |= SYMBOL_DEF_USER;
713 		sym_set_changed(sym);
714 	}
715 
716 	oldval = sym->def[S_DEF_USER].val;
717 	size = strlen(newval) + 1;
718 	if (sym->type == S_HEX && (newval[0] != '0' || (newval[1] != 'x' && newval[1] != 'X'))) {
719 		size += 2;
720 		sym->def[S_DEF_USER].val = val = xmalloc(size);
721 		*val++ = '0';
722 		*val++ = 'x';
723 	} else if (!oldval || strcmp(oldval, newval))
724 		sym->def[S_DEF_USER].val = val = xmalloc(size);
725 	else
726 		return true;
727 
728 	strcpy(val, newval);
729 	free((void *)oldval);
730 	sym_clear_all_valid();
731 
732 	return true;
733 }
734 
735 /*
736  * Find the default value associated to a symbol.
737  * For tristate symbol handle the modules=n case
738  * in which case "m" becomes "y".
739  * If the symbol does not have any default then fallback
740  * to the fixed default values.
741  */
742 const char *sym_get_string_default(struct symbol *sym)
743 {
744 	struct property *prop;
745 	struct symbol *ds;
746 	const char *str = "";
747 	tristate val;
748 
749 	sym_calc_visibility(sym);
750 	sym_calc_value(modules_sym);
751 	val = symbol_no.curr.tri;
752 
753 	/* If symbol has a default value look it up */
754 	prop = sym_get_default_prop(sym);
755 	if (prop != NULL) {
756 		switch (sym->type) {
757 		case S_BOOLEAN:
758 		case S_TRISTATE:
759 			/* The visibility may limit the value from yes => mod */
760 			val = EXPR_AND(expr_calc_value(prop->expr), prop->visible.tri);
761 			break;
762 		default:
763 			/*
764 			 * The following fails to handle the situation
765 			 * where a default value is further limited by
766 			 * the valid range.
767 			 */
768 			ds = prop_get_symbol(prop);
769 			if (ds != NULL) {
770 				sym_calc_value(ds);
771 				str = (const char *)ds->curr.val;
772 			}
773 		}
774 	}
775 
776 	/* Handle select statements */
777 	val = EXPR_OR(val, sym->rev_dep.tri);
778 
779 	/* transpose mod to yes if modules are not enabled */
780 	if (val == mod)
781 		if (!sym_is_choice_value(sym) && modules_sym->curr.tri == no)
782 			val = yes;
783 
784 	/* transpose mod to yes if type is bool */
785 	if (sym->type == S_BOOLEAN && val == mod)
786 		val = yes;
787 
788 	/* adjust the default value if this symbol is implied by another */
789 	if (val < sym->implied.tri)
790 		val = sym->implied.tri;
791 
792 	switch (sym->type) {
793 	case S_BOOLEAN:
794 	case S_TRISTATE:
795 		switch (val) {
796 		case no: return "n";
797 		case mod: return "m";
798 		case yes: return "y";
799 		}
800 	case S_INT:
801 		if (!str[0])
802 			str = "0";
803 		break;
804 	case S_HEX:
805 		if (!str[0])
806 			str = "0x0";
807 		break;
808 	default:
809 		break;
810 	}
811 	return str;
812 }
813 
814 const char *sym_get_string_value(struct symbol *sym)
815 {
816 	tristate val;
817 
818 	switch (sym->type) {
819 	case S_BOOLEAN:
820 	case S_TRISTATE:
821 		val = sym_get_tristate_value(sym);
822 		switch (val) {
823 		case no:
824 			return "n";
825 		case mod:
826 			return "m";
827 		case yes:
828 			return "y";
829 		}
830 		break;
831 	default:
832 		;
833 	}
834 	return (const char *)sym->curr.val;
835 }
836 
837 bool sym_is_changeable(struct symbol *sym)
838 {
839 	return sym->visible > sym->rev_dep.tri;
840 }
841 
842 HASHTABLE_DEFINE(sym_hashtable, SYMBOL_HASHSIZE);
843 
844 struct symbol *sym_lookup(const char *name, int flags)
845 {
846 	struct symbol *symbol;
847 	char *new_name;
848 	int hash;
849 
850 	if (name) {
851 		if (name[0] && !name[1]) {
852 			switch (name[0]) {
853 			case 'y': return &symbol_yes;
854 			case 'm': return &symbol_mod;
855 			case 'n': return &symbol_no;
856 			}
857 		}
858 		hash = strhash(name);
859 
860 		hash_for_each_possible(sym_hashtable, symbol, node, hash) {
861 			if (symbol->name &&
862 			    !strcmp(symbol->name, name) &&
863 			    (flags ? symbol->flags & flags
864 				   : !(symbol->flags & SYMBOL_CONST)))
865 				return symbol;
866 		}
867 		new_name = xstrdup(name);
868 	} else {
869 		new_name = NULL;
870 		hash = 0;
871 	}
872 
873 	symbol = xmalloc(sizeof(*symbol));
874 	memset(symbol, 0, sizeof(*symbol));
875 	symbol->name = new_name;
876 	symbol->type = S_UNKNOWN;
877 	symbol->flags = flags;
878 	INIT_LIST_HEAD(&symbol->menus);
879 
880 	hash_add(sym_hashtable, &symbol->node, hash);
881 
882 	return symbol;
883 }
884 
885 struct symbol *sym_find(const char *name)
886 {
887 	struct symbol *symbol = NULL;
888 	int hash = 0;
889 
890 	if (!name)
891 		return NULL;
892 
893 	if (name[0] && !name[1]) {
894 		switch (name[0]) {
895 		case 'y': return &symbol_yes;
896 		case 'm': return &symbol_mod;
897 		case 'n': return &symbol_no;
898 		}
899 	}
900 	hash = strhash(name);
901 
902 	hash_for_each_possible(sym_hashtable, symbol, node, hash) {
903 		if (symbol->name &&
904 		    !strcmp(symbol->name, name) &&
905 		    !(symbol->flags & SYMBOL_CONST))
906 				break;
907 	}
908 
909 	return symbol;
910 }
911 
912 struct sym_match {
913 	struct symbol	*sym;
914 	off_t		so, eo;
915 };
916 
917 /* Compare matched symbols as thus:
918  * - first, symbols that match exactly
919  * - then, alphabetical sort
920  */
921 static int sym_rel_comp(const void *sym1, const void *sym2)
922 {
923 	const struct sym_match *s1 = sym1;
924 	const struct sym_match *s2 = sym2;
925 	int exact1, exact2;
926 
927 	/* Exact match:
928 	 * - if matched length on symbol s1 is the length of that symbol,
929 	 *   then this symbol should come first;
930 	 * - if matched length on symbol s2 is the length of that symbol,
931 	 *   then this symbol should come first.
932 	 * Note: since the search can be a regexp, both symbols may match
933 	 * exactly; if this is the case, we can't decide which comes first,
934 	 * and we fallback to sorting alphabetically.
935 	 */
936 	exact1 = (s1->eo - s1->so) == strlen(s1->sym->name);
937 	exact2 = (s2->eo - s2->so) == strlen(s2->sym->name);
938 	if (exact1 && !exact2)
939 		return -1;
940 	if (!exact1 && exact2)
941 		return 1;
942 
943 	/* As a fallback, sort symbols alphabetically */
944 	return strcmp(s1->sym->name, s2->sym->name);
945 }
946 
947 struct symbol **sym_re_search(const char *pattern)
948 {
949 	struct symbol *sym, **sym_arr = NULL;
950 	struct sym_match *sym_match_arr = NULL;
951 	int i, cnt, size;
952 	regex_t re;
953 	regmatch_t match[1];
954 
955 	cnt = size = 0;
956 	/* Skip if empty */
957 	if (strlen(pattern) == 0)
958 		return NULL;
959 	if (regcomp(&re, pattern, REG_EXTENDED|REG_ICASE))
960 		return NULL;
961 
962 	for_all_symbols(sym) {
963 		if (sym->flags & SYMBOL_CONST || !sym->name)
964 			continue;
965 		if (regexec(&re, sym->name, 1, match, 0))
966 			continue;
967 		if (cnt >= size) {
968 			void *tmp;
969 			size += 16;
970 			tmp = realloc(sym_match_arr, size * sizeof(struct sym_match));
971 			if (!tmp)
972 				goto sym_re_search_free;
973 			sym_match_arr = tmp;
974 		}
975 		sym_calc_value(sym);
976 		/* As regexec returned 0, we know we have a match, so
977 		 * we can use match[0].rm_[se]o without further checks
978 		 */
979 		sym_match_arr[cnt].so = match[0].rm_so;
980 		sym_match_arr[cnt].eo = match[0].rm_eo;
981 		sym_match_arr[cnt++].sym = sym;
982 	}
983 	if (sym_match_arr) {
984 		qsort(sym_match_arr, cnt, sizeof(struct sym_match), sym_rel_comp);
985 		sym_arr = malloc((cnt+1) * sizeof(struct symbol *));
986 		if (!sym_arr)
987 			goto sym_re_search_free;
988 		for (i = 0; i < cnt; i++)
989 			sym_arr[i] = sym_match_arr[i].sym;
990 		sym_arr[cnt] = NULL;
991 	}
992 sym_re_search_free:
993 	/* sym_match_arr can be NULL if no match, but free(NULL) is OK */
994 	free(sym_match_arr);
995 	regfree(&re);
996 
997 	return sym_arr;
998 }
999 
1000 /*
1001  * When we check for recursive dependencies we use a stack to save
1002  * current state so we can print out relevant info to user.
1003  * The entries are located on the call stack so no need to free memory.
1004  * Note insert() remove() must always match to properly clear the stack.
1005  */
1006 static struct dep_stack {
1007 	struct dep_stack *prev, *next;
1008 	struct symbol *sym;
1009 	struct property *prop;
1010 	struct expr **expr;
1011 } *check_top;
1012 
1013 static void dep_stack_insert(struct dep_stack *stack, struct symbol *sym)
1014 {
1015 	memset(stack, 0, sizeof(*stack));
1016 	if (check_top)
1017 		check_top->next = stack;
1018 	stack->prev = check_top;
1019 	stack->sym = sym;
1020 	check_top = stack;
1021 }
1022 
1023 static void dep_stack_remove(void)
1024 {
1025 	check_top = check_top->prev;
1026 	if (check_top)
1027 		check_top->next = NULL;
1028 }
1029 
1030 /*
1031  * Called when we have detected a recursive dependency.
1032  * check_top point to the top of the stact so we use
1033  * the ->prev pointer to locate the bottom of the stack.
1034  */
1035 static void sym_check_print_recursive(struct symbol *last_sym)
1036 {
1037 	struct dep_stack *stack;
1038 	struct symbol *sym, *next_sym;
1039 	struct menu *menu = NULL;
1040 	struct property *prop;
1041 	struct dep_stack cv_stack;
1042 
1043 	if (sym_is_choice_value(last_sym)) {
1044 		dep_stack_insert(&cv_stack, last_sym);
1045 		last_sym = prop_get_symbol(sym_get_choice_prop(last_sym));
1046 	}
1047 
1048 	for (stack = check_top; stack != NULL; stack = stack->prev)
1049 		if (stack->sym == last_sym)
1050 			break;
1051 	if (!stack) {
1052 		fprintf(stderr, "unexpected recursive dependency error\n");
1053 		return;
1054 	}
1055 
1056 	for (; stack; stack = stack->next) {
1057 		sym = stack->sym;
1058 		next_sym = stack->next ? stack->next->sym : last_sym;
1059 		prop = stack->prop;
1060 		if (prop == NULL)
1061 			prop = stack->sym->prop;
1062 
1063 		/* for choice values find the menu entry (used below) */
1064 		if (sym_is_choice(sym) || sym_is_choice_value(sym)) {
1065 			for (prop = sym->prop; prop; prop = prop->next) {
1066 				menu = prop->menu;
1067 				if (prop->menu)
1068 					break;
1069 			}
1070 		}
1071 		if (stack->sym == last_sym)
1072 			fprintf(stderr, "%s:%d:error: recursive dependency detected!\n",
1073 				prop->filename, prop->lineno);
1074 
1075 		if (sym_is_choice(sym)) {
1076 			fprintf(stderr, "%s:%d:\tchoice %s contains symbol %s\n",
1077 				menu->filename, menu->lineno,
1078 				sym->name ? sym->name : "<choice>",
1079 				next_sym->name ? next_sym->name : "<choice>");
1080 		} else if (sym_is_choice_value(sym)) {
1081 			fprintf(stderr, "%s:%d:\tsymbol %s is part of choice %s\n",
1082 				menu->filename, menu->lineno,
1083 				sym->name ? sym->name : "<choice>",
1084 				next_sym->name ? next_sym->name : "<choice>");
1085 		} else if (stack->expr == &sym->dir_dep.expr) {
1086 			fprintf(stderr, "%s:%d:\tsymbol %s depends on %s\n",
1087 				prop->filename, prop->lineno,
1088 				sym->name ? sym->name : "<choice>",
1089 				next_sym->name ? next_sym->name : "<choice>");
1090 		} else if (stack->expr == &sym->rev_dep.expr) {
1091 			fprintf(stderr, "%s:%d:\tsymbol %s is selected by %s\n",
1092 				prop->filename, prop->lineno,
1093 				sym->name ? sym->name : "<choice>",
1094 				next_sym->name ? next_sym->name : "<choice>");
1095 		} else if (stack->expr == &sym->implied.expr) {
1096 			fprintf(stderr, "%s:%d:\tsymbol %s is implied by %s\n",
1097 				prop->filename, prop->lineno,
1098 				sym->name ? sym->name : "<choice>",
1099 				next_sym->name ? next_sym->name : "<choice>");
1100 		} else if (stack->expr) {
1101 			fprintf(stderr, "%s:%d:\tsymbol %s %s value contains %s\n",
1102 				prop->filename, prop->lineno,
1103 				sym->name ? sym->name : "<choice>",
1104 				prop_get_type_name(prop->type),
1105 				next_sym->name ? next_sym->name : "<choice>");
1106 		} else {
1107 			fprintf(stderr, "%s:%d:\tsymbol %s %s is visible depending on %s\n",
1108 				prop->filename, prop->lineno,
1109 				sym->name ? sym->name : "<choice>",
1110 				prop_get_type_name(prop->type),
1111 				next_sym->name ? next_sym->name : "<choice>");
1112 		}
1113 	}
1114 
1115 	fprintf(stderr,
1116 		"For a resolution refer to Documentation/kbuild/kconfig-language.rst\n"
1117 		"subsection \"Kconfig recursive dependency limitations\"\n"
1118 		"\n");
1119 
1120 	if (check_top == &cv_stack)
1121 		dep_stack_remove();
1122 }
1123 
1124 static struct symbol *sym_check_expr_deps(struct expr *e)
1125 {
1126 	struct symbol *sym;
1127 
1128 	if (!e)
1129 		return NULL;
1130 	switch (e->type) {
1131 	case E_OR:
1132 	case E_AND:
1133 		sym = sym_check_expr_deps(e->left.expr);
1134 		if (sym)
1135 			return sym;
1136 		return sym_check_expr_deps(e->right.expr);
1137 	case E_NOT:
1138 		return sym_check_expr_deps(e->left.expr);
1139 	case E_EQUAL:
1140 	case E_GEQ:
1141 	case E_GTH:
1142 	case E_LEQ:
1143 	case E_LTH:
1144 	case E_UNEQUAL:
1145 		sym = sym_check_deps(e->left.sym);
1146 		if (sym)
1147 			return sym;
1148 		return sym_check_deps(e->right.sym);
1149 	case E_SYMBOL:
1150 		return sym_check_deps(e->left.sym);
1151 	default:
1152 		break;
1153 	}
1154 	fprintf(stderr, "Oops! How to check %d?\n", e->type);
1155 	return NULL;
1156 }
1157 
1158 /* return NULL when dependencies are OK */
1159 static struct symbol *sym_check_sym_deps(struct symbol *sym)
1160 {
1161 	struct symbol *sym2;
1162 	struct property *prop;
1163 	struct dep_stack stack;
1164 
1165 	dep_stack_insert(&stack, sym);
1166 
1167 	stack.expr = &sym->dir_dep.expr;
1168 	sym2 = sym_check_expr_deps(sym->dir_dep.expr);
1169 	if (sym2)
1170 		goto out;
1171 
1172 	stack.expr = &sym->rev_dep.expr;
1173 	sym2 = sym_check_expr_deps(sym->rev_dep.expr);
1174 	if (sym2)
1175 		goto out;
1176 
1177 	stack.expr = &sym->implied.expr;
1178 	sym2 = sym_check_expr_deps(sym->implied.expr);
1179 	if (sym2)
1180 		goto out;
1181 
1182 	stack.expr = NULL;
1183 
1184 	for (prop = sym->prop; prop; prop = prop->next) {
1185 		if (prop->type == P_CHOICE || prop->type == P_SELECT ||
1186 		    prop->type == P_IMPLY)
1187 			continue;
1188 		stack.prop = prop;
1189 		sym2 = sym_check_expr_deps(prop->visible.expr);
1190 		if (sym2)
1191 			break;
1192 		if (prop->type != P_DEFAULT || sym_is_choice(sym))
1193 			continue;
1194 		stack.expr = &prop->expr;
1195 		sym2 = sym_check_expr_deps(prop->expr);
1196 		if (sym2)
1197 			break;
1198 		stack.expr = NULL;
1199 	}
1200 
1201 out:
1202 	dep_stack_remove();
1203 
1204 	return sym2;
1205 }
1206 
1207 static struct symbol *sym_check_choice_deps(struct symbol *choice)
1208 {
1209 	struct menu *choice_menu, *menu;
1210 	struct symbol *sym2;
1211 	struct dep_stack stack;
1212 
1213 	dep_stack_insert(&stack, choice);
1214 
1215 	choice_menu = list_first_entry(&choice->menus, struct menu, link);
1216 
1217 	menu_for_each_sub_entry(menu, choice_menu) {
1218 		if (menu->sym)
1219 			menu->sym->flags |= SYMBOL_CHECK | SYMBOL_CHECKED;
1220 	}
1221 
1222 	choice->flags |= (SYMBOL_CHECK | SYMBOL_CHECKED);
1223 	sym2 = sym_check_sym_deps(choice);
1224 	choice->flags &= ~SYMBOL_CHECK;
1225 	if (sym2)
1226 		goto out;
1227 
1228 	menu_for_each_sub_entry(menu, choice_menu) {
1229 		if (!menu->sym)
1230 			continue;
1231 		sym2 = sym_check_sym_deps(menu->sym);
1232 		if (sym2)
1233 			break;
1234 	}
1235 out:
1236 	menu_for_each_sub_entry(menu, choice_menu)
1237 		if (menu->sym)
1238 			menu->sym->flags &= ~SYMBOL_CHECK;
1239 
1240 	if (sym2 && sym_is_choice_value(sym2) &&
1241 	    prop_get_symbol(sym_get_choice_prop(sym2)) == choice)
1242 		sym2 = choice;
1243 
1244 	dep_stack_remove();
1245 
1246 	return sym2;
1247 }
1248 
1249 struct symbol *sym_check_deps(struct symbol *sym)
1250 {
1251 	struct symbol *sym2;
1252 	struct property *prop;
1253 
1254 	if (sym->flags & SYMBOL_CHECK) {
1255 		sym_check_print_recursive(sym);
1256 		return sym;
1257 	}
1258 	if (sym->flags & SYMBOL_CHECKED)
1259 		return NULL;
1260 
1261 	if (sym_is_choice_value(sym)) {
1262 		struct dep_stack stack;
1263 
1264 		/* for choice groups start the check with main choice symbol */
1265 		dep_stack_insert(&stack, sym);
1266 		prop = sym_get_choice_prop(sym);
1267 		sym2 = sym_check_deps(prop_get_symbol(prop));
1268 		dep_stack_remove();
1269 	} else if (sym_is_choice(sym)) {
1270 		sym2 = sym_check_choice_deps(sym);
1271 	} else {
1272 		sym->flags |= (SYMBOL_CHECK | SYMBOL_CHECKED);
1273 		sym2 = sym_check_sym_deps(sym);
1274 		sym->flags &= ~SYMBOL_CHECK;
1275 	}
1276 
1277 	return sym2;
1278 }
1279 
1280 struct symbol *prop_get_symbol(struct property *prop)
1281 {
1282 	if (prop->expr && (prop->expr->type == E_SYMBOL ||
1283 			   prop->expr->type == E_LIST))
1284 		return prop->expr->left.sym;
1285 	return NULL;
1286 }
1287 
1288 const char *prop_get_type_name(enum prop_type type)
1289 {
1290 	switch (type) {
1291 	case P_PROMPT:
1292 		return "prompt";
1293 	case P_COMMENT:
1294 		return "comment";
1295 	case P_MENU:
1296 		return "menu";
1297 	case P_DEFAULT:
1298 		return "default";
1299 	case P_CHOICE:
1300 		return "choice";
1301 	case P_SELECT:
1302 		return "select";
1303 	case P_IMPLY:
1304 		return "imply";
1305 	case P_RANGE:
1306 		return "range";
1307 	case P_SYMBOL:
1308 		return "symbol";
1309 	case P_UNKNOWN:
1310 		break;
1311 	}
1312 	return "unknown";
1313 }
1314