xref: /linux/scripts/kconfig/symbol.c (revision ed3174d93c342b8b2eeba6bbd124707d55304a7b) 
1 /*
2  * Copyright (C) 2002 Roman Zippel <zippel@linux-m68k.org>
3  * Released under the terms of the GNU GPL v2.0.
4  */
5 
6 #include <ctype.h>
7 #include <stdlib.h>
8 #include <string.h>
9 #include <regex.h>
10 #include <sys/utsname.h>
11 
12 #define LKC_DIRECT_LINK
13 #include "lkc.h"
14 
15 struct symbol symbol_yes = {
16 	.name = "y",
17 	.curr = { "y", yes },
18 	.flags = SYMBOL_CONST|SYMBOL_VALID,
19 }, symbol_mod = {
20 	.name = "m",
21 	.curr = { "m", mod },
22 	.flags = SYMBOL_CONST|SYMBOL_VALID,
23 }, symbol_no = {
24 	.name = "n",
25 	.curr = { "n", no },
26 	.flags = SYMBOL_CONST|SYMBOL_VALID,
27 }, symbol_empty = {
28 	.name = "",
29 	.curr = { "", no },
30 	.flags = SYMBOL_VALID,
31 };
32 
33 struct symbol *sym_defconfig_list;
34 struct symbol *modules_sym;
35 tristate modules_val;
36 
37 struct expr *sym_env_list;
38 
39 void sym_add_default(struct symbol *sym, const char *def)
40 {
41 	struct property *prop = prop_alloc(P_DEFAULT, sym);
42 
43 	prop->expr = expr_alloc_symbol(sym_lookup(def, 1));
44 }
45 
46 void sym_init(void)
47 {
48 	struct symbol *sym;
49 	struct utsname uts;
50 	static bool inited = false;
51 
52 	if (inited)
53 		return;
54 	inited = true;
55 
56 	uname(&uts);
57 
58 	sym = sym_lookup("UNAME_RELEASE", 0);
59 	sym->type = S_STRING;
60 	sym->flags |= SYMBOL_AUTO;
61 	sym_add_default(sym, uts.release);
62 }
63 
64 enum symbol_type sym_get_type(struct symbol *sym)
65 {
66 	enum symbol_type type = sym->type;
67 
68 	if (type == S_TRISTATE) {
69 		if (sym_is_choice_value(sym) && sym->visible == yes)
70 			type = S_BOOLEAN;
71 		else if (modules_val == no)
72 			type = S_BOOLEAN;
73 	}
74 	return type;
75 }
76 
77 const char *sym_type_name(enum symbol_type type)
78 {
79 	switch (type) {
80 	case S_BOOLEAN:
81 		return "boolean";
82 	case S_TRISTATE:
83 		return "tristate";
84 	case S_INT:
85 		return "integer";
86 	case S_HEX:
87 		return "hex";
88 	case S_STRING:
89 		return "string";
90 	case S_UNKNOWN:
91 		return "unknown";
92 	case S_OTHER:
93 		break;
94 	}
95 	return "???";
96 }
97 
98 struct property *sym_get_choice_prop(struct symbol *sym)
99 {
100 	struct property *prop;
101 
102 	for_all_choices(sym, prop)
103 		return prop;
104 	return NULL;
105 }
106 
107 struct property *sym_get_env_prop(struct symbol *sym)
108 {
109 	struct property *prop;
110 
111 	for_all_properties(sym, prop, P_ENV)
112 		return prop;
113 	return NULL;
114 }
115 
116 struct property *sym_get_default_prop(struct symbol *sym)
117 {
118 	struct property *prop;
119 
120 	for_all_defaults(sym, prop) {
121 		prop->visible.tri = expr_calc_value(prop->visible.expr);
122 		if (prop->visible.tri != no)
123 			return prop;
124 	}
125 	return NULL;
126 }
127 
128 struct property *sym_get_range_prop(struct symbol *sym)
129 {
130 	struct property *prop;
131 
132 	for_all_properties(sym, prop, P_RANGE) {
133 		prop->visible.tri = expr_calc_value(prop->visible.expr);
134 		if (prop->visible.tri != no)
135 			return prop;
136 	}
137 	return NULL;
138 }
139 
140 static int sym_get_range_val(struct symbol *sym, int base)
141 {
142 	sym_calc_value(sym);
143 	switch (sym->type) {
144 	case S_INT:
145 		base = 10;
146 		break;
147 	case S_HEX:
148 		base = 16;
149 		break;
150 	default:
151 		break;
152 	}
153 	return strtol(sym->curr.val, NULL, base);
154 }
155 
156 static void sym_validate_range(struct symbol *sym)
157 {
158 	struct property *prop;
159 	int base, val, val2;
160 	char str[64];
161 
162 	switch (sym->type) {
163 	case S_INT:
164 		base = 10;
165 		break;
166 	case S_HEX:
167 		base = 16;
168 		break;
169 	default:
170 		return;
171 	}
172 	prop = sym_get_range_prop(sym);
173 	if (!prop)
174 		return;
175 	val = strtol(sym->curr.val, NULL, base);
176 	val2 = sym_get_range_val(prop->expr->left.sym, base);
177 	if (val >= val2) {
178 		val2 = sym_get_range_val(prop->expr->right.sym, base);
179 		if (val <= val2)
180 			return;
181 	}
182 	if (sym->type == S_INT)
183 		sprintf(str, "%d", val2);
184 	else
185 		sprintf(str, "0x%x", val2);
186 	sym->curr.val = strdup(str);
187 }
188 
189 static void sym_calc_visibility(struct symbol *sym)
190 {
191 	struct property *prop;
192 	tristate tri;
193 
194 	/* any prompt visible? */
195 	tri = no;
196 	for_all_prompts(sym, prop) {
197 		prop->visible.tri = expr_calc_value(prop->visible.expr);
198 		tri = EXPR_OR(tri, prop->visible.tri);
199 	}
200 	if (tri == mod && (sym->type != S_TRISTATE || modules_val == no))
201 		tri = yes;
202 	if (sym->visible != tri) {
203 		sym->visible = tri;
204 		sym_set_changed(sym);
205 	}
206 	if (sym_is_choice_value(sym))
207 		return;
208 	tri = no;
209 	if (sym->rev_dep.expr)
210 		tri = expr_calc_value(sym->rev_dep.expr);
211 	if (tri == mod && sym_get_type(sym) == S_BOOLEAN)
212 		tri = yes;
213 	if (sym->rev_dep.tri != tri) {
214 		sym->rev_dep.tri = tri;
215 		sym_set_changed(sym);
216 	}
217 }
218 
219 static struct symbol *sym_calc_choice(struct symbol *sym)
220 {
221 	struct symbol *def_sym;
222 	struct property *prop;
223 	struct expr *e;
224 
225 	/* is the user choice visible? */
226 	def_sym = sym->def[S_DEF_USER].val;
227 	if (def_sym) {
228 		sym_calc_visibility(def_sym);
229 		if (def_sym->visible != no)
230 			return def_sym;
231 	}
232 
233 	/* any of the defaults visible? */
234 	for_all_defaults(sym, prop) {
235 		prop->visible.tri = expr_calc_value(prop->visible.expr);
236 		if (prop->visible.tri == no)
237 			continue;
238 		def_sym = prop_get_symbol(prop);
239 		sym_calc_visibility(def_sym);
240 		if (def_sym->visible != no)
241 			return def_sym;
242 	}
243 
244 	/* just get the first visible value */
245 	prop = sym_get_choice_prop(sym);
246 	expr_list_for_each_sym(prop->expr, e, def_sym) {
247 		sym_calc_visibility(def_sym);
248 		if (def_sym->visible != no)
249 			return def_sym;
250 	}
251 
252 	/* no choice? reset tristate value */
253 	sym->curr.tri = no;
254 	return NULL;
255 }
256 
257 void sym_calc_value(struct symbol *sym)
258 {
259 	struct symbol_value newval, oldval;
260 	struct property *prop;
261 	struct expr *e;
262 
263 	if (!sym)
264 		return;
265 
266 	if (sym->flags & SYMBOL_VALID)
267 		return;
268 	sym->flags |= SYMBOL_VALID;
269 
270 	oldval = sym->curr;
271 
272 	switch (sym->type) {
273 	case S_INT:
274 	case S_HEX:
275 	case S_STRING:
276 		newval = symbol_empty.curr;
277 		break;
278 	case S_BOOLEAN:
279 	case S_TRISTATE:
280 		newval = symbol_no.curr;
281 		break;
282 	default:
283 		sym->curr.val = sym->name;
284 		sym->curr.tri = no;
285 		return;
286 	}
287 	if (!sym_is_choice_value(sym))
288 		sym->flags &= ~SYMBOL_WRITE;
289 
290 	sym_calc_visibility(sym);
291 
292 	/* set default if recursively called */
293 	sym->curr = newval;
294 
295 	switch (sym_get_type(sym)) {
296 	case S_BOOLEAN:
297 	case S_TRISTATE:
298 		if (sym_is_choice_value(sym) && sym->visible == yes) {
299 			prop = sym_get_choice_prop(sym);
300 			newval.tri = (prop_get_symbol(prop)->curr.val == sym) ? yes : no;
301 		} else if (EXPR_OR(sym->visible, sym->rev_dep.tri) != no) {
302 			sym->flags |= SYMBOL_WRITE;
303 			if (sym_has_value(sym))
304 				newval.tri = sym->def[S_DEF_USER].tri;
305 			else if (!sym_is_choice(sym)) {
306 				prop = sym_get_default_prop(sym);
307 				if (prop)
308 					newval.tri = expr_calc_value(prop->expr);
309 			}
310 			newval.tri = EXPR_OR(EXPR_AND(newval.tri, sym->visible), sym->rev_dep.tri);
311 		} else if (!sym_is_choice(sym)) {
312 			prop = sym_get_default_prop(sym);
313 			if (prop) {
314 				sym->flags |= SYMBOL_WRITE;
315 				newval.tri = expr_calc_value(prop->expr);
316 			}
317 		}
318 		if (newval.tri == mod && sym_get_type(sym) == S_BOOLEAN)
319 			newval.tri = yes;
320 		break;
321 	case S_STRING:
322 	case S_HEX:
323 	case S_INT:
324 		if (sym->visible != no) {
325 			sym->flags |= SYMBOL_WRITE;
326 			if (sym_has_value(sym)) {
327 				newval.val = sym->def[S_DEF_USER].val;
328 				break;
329 			}
330 		}
331 		prop = sym_get_default_prop(sym);
332 		if (prop) {
333 			struct symbol *ds = prop_get_symbol(prop);
334 			if (ds) {
335 				sym->flags |= SYMBOL_WRITE;
336 				sym_calc_value(ds);
337 				newval.val = ds->curr.val;
338 			}
339 		}
340 		break;
341 	default:
342 		;
343 	}
344 
345 	if (sym->flags & SYMBOL_AUTO)
346 		sym->flags &= ~SYMBOL_WRITE;
347 
348 	sym->curr = newval;
349 	if (sym_is_choice(sym) && newval.tri == yes)
350 		sym->curr.val = sym_calc_choice(sym);
351 	sym_validate_range(sym);
352 
353 	if (memcmp(&oldval, &sym->curr, sizeof(oldval))) {
354 		sym_set_changed(sym);
355 		if (modules_sym == sym) {
356 			sym_set_all_changed();
357 			modules_val = modules_sym->curr.tri;
358 		}
359 	}
360 
361 	if (sym_is_choice(sym)) {
362 		struct symbol *choice_sym;
363 		int flags = sym->flags & (SYMBOL_CHANGED | SYMBOL_WRITE);
364 
365 		prop = sym_get_choice_prop(sym);
366 		expr_list_for_each_sym(prop->expr, e, choice_sym) {
367 			choice_sym->flags |= flags;
368 			if (flags & SYMBOL_CHANGED)
369 				sym_set_changed(choice_sym);
370 		}
371 	}
372 }
373 
374 void sym_clear_all_valid(void)
375 {
376 	struct symbol *sym;
377 	int i;
378 
379 	for_all_symbols(i, sym)
380 		sym->flags &= ~SYMBOL_VALID;
381 	sym_add_change_count(1);
382 	if (modules_sym)
383 		sym_calc_value(modules_sym);
384 }
385 
386 void sym_set_changed(struct symbol *sym)
387 {
388 	struct property *prop;
389 
390 	sym->flags |= SYMBOL_CHANGED;
391 	for (prop = sym->prop; prop; prop = prop->next) {
392 		if (prop->menu)
393 			prop->menu->flags |= MENU_CHANGED;
394 	}
395 }
396 
397 void sym_set_all_changed(void)
398 {
399 	struct symbol *sym;
400 	int i;
401 
402 	for_all_symbols(i, sym)
403 		sym_set_changed(sym);
404 }
405 
406 bool sym_tristate_within_range(struct symbol *sym, tristate val)
407 {
408 	int type = sym_get_type(sym);
409 
410 	if (sym->visible == no)
411 		return false;
412 
413 	if (type != S_BOOLEAN && type != S_TRISTATE)
414 		return false;
415 
416 	if (type == S_BOOLEAN && val == mod)
417 		return false;
418 	if (sym->visible <= sym->rev_dep.tri)
419 		return false;
420 	if (sym_is_choice_value(sym) && sym->visible == yes)
421 		return val == yes;
422 	return val >= sym->rev_dep.tri && val <= sym->visible;
423 }
424 
425 bool sym_set_tristate_value(struct symbol *sym, tristate val)
426 {
427 	tristate oldval = sym_get_tristate_value(sym);
428 
429 	if (oldval != val && !sym_tristate_within_range(sym, val))
430 		return false;
431 
432 	if (!(sym->flags & SYMBOL_DEF_USER)) {
433 		sym->flags |= SYMBOL_DEF_USER;
434 		sym_set_changed(sym);
435 	}
436 	/*
437 	 * setting a choice value also resets the new flag of the choice
438 	 * symbol and all other choice values.
439 	 */
440 	if (sym_is_choice_value(sym) && val == yes) {
441 		struct symbol *cs = prop_get_symbol(sym_get_choice_prop(sym));
442 		struct property *prop;
443 		struct expr *e;
444 
445 		cs->def[S_DEF_USER].val = sym;
446 		cs->flags |= SYMBOL_DEF_USER;
447 		prop = sym_get_choice_prop(cs);
448 		for (e = prop->expr; e; e = e->left.expr) {
449 			if (e->right.sym->visible != no)
450 				e->right.sym->flags |= SYMBOL_DEF_USER;
451 		}
452 	}
453 
454 	sym->def[S_DEF_USER].tri = val;
455 	if (oldval != val)
456 		sym_clear_all_valid();
457 
458 	return true;
459 }
460 
461 tristate sym_toggle_tristate_value(struct symbol *sym)
462 {
463 	tristate oldval, newval;
464 
465 	oldval = newval = sym_get_tristate_value(sym);
466 	do {
467 		switch (newval) {
468 		case no:
469 			newval = mod;
470 			break;
471 		case mod:
472 			newval = yes;
473 			break;
474 		case yes:
475 			newval = no;
476 			break;
477 		}
478 		if (sym_set_tristate_value(sym, newval))
479 			break;
480 	} while (oldval != newval);
481 	return newval;
482 }
483 
484 bool sym_string_valid(struct symbol *sym, const char *str)
485 {
486 	signed char ch;
487 
488 	switch (sym->type) {
489 	case S_STRING:
490 		return true;
491 	case S_INT:
492 		ch = *str++;
493 		if (ch == '-')
494 			ch = *str++;
495 		if (!isdigit(ch))
496 			return false;
497 		if (ch == '0' && *str != 0)
498 			return false;
499 		while ((ch = *str++)) {
500 			if (!isdigit(ch))
501 				return false;
502 		}
503 		return true;
504 	case S_HEX:
505 		if (str[0] == '0' && (str[1] == 'x' || str[1] == 'X'))
506 			str += 2;
507 		ch = *str++;
508 		do {
509 			if (!isxdigit(ch))
510 				return false;
511 		} while ((ch = *str++));
512 		return true;
513 	case S_BOOLEAN:
514 	case S_TRISTATE:
515 		switch (str[0]) {
516 		case 'y': case 'Y':
517 		case 'm': case 'M':
518 		case 'n': case 'N':
519 			return true;
520 		}
521 		return false;
522 	default:
523 		return false;
524 	}
525 }
526 
527 bool sym_string_within_range(struct symbol *sym, const char *str)
528 {
529 	struct property *prop;
530 	int val;
531 
532 	switch (sym->type) {
533 	case S_STRING:
534 		return sym_string_valid(sym, str);
535 	case S_INT:
536 		if (!sym_string_valid(sym, str))
537 			return false;
538 		prop = sym_get_range_prop(sym);
539 		if (!prop)
540 			return true;
541 		val = strtol(str, NULL, 10);
542 		return val >= sym_get_range_val(prop->expr->left.sym, 10) &&
543 		       val <= sym_get_range_val(prop->expr->right.sym, 10);
544 	case S_HEX:
545 		if (!sym_string_valid(sym, str))
546 			return false;
547 		prop = sym_get_range_prop(sym);
548 		if (!prop)
549 			return true;
550 		val = strtol(str, NULL, 16);
551 		return val >= sym_get_range_val(prop->expr->left.sym, 16) &&
552 		       val <= sym_get_range_val(prop->expr->right.sym, 16);
553 	case S_BOOLEAN:
554 	case S_TRISTATE:
555 		switch (str[0]) {
556 		case 'y': case 'Y':
557 			return sym_tristate_within_range(sym, yes);
558 		case 'm': case 'M':
559 			return sym_tristate_within_range(sym, mod);
560 		case 'n': case 'N':
561 			return sym_tristate_within_range(sym, no);
562 		}
563 		return false;
564 	default:
565 		return false;
566 	}
567 }
568 
569 bool sym_set_string_value(struct symbol *sym, const char *newval)
570 {
571 	const char *oldval;
572 	char *val;
573 	int size;
574 
575 	switch (sym->type) {
576 	case S_BOOLEAN:
577 	case S_TRISTATE:
578 		switch (newval[0]) {
579 		case 'y': case 'Y':
580 			return sym_set_tristate_value(sym, yes);
581 		case 'm': case 'M':
582 			return sym_set_tristate_value(sym, mod);
583 		case 'n': case 'N':
584 			return sym_set_tristate_value(sym, no);
585 		}
586 		return false;
587 	default:
588 		;
589 	}
590 
591 	if (!sym_string_within_range(sym, newval))
592 		return false;
593 
594 	if (!(sym->flags & SYMBOL_DEF_USER)) {
595 		sym->flags |= SYMBOL_DEF_USER;
596 		sym_set_changed(sym);
597 	}
598 
599 	oldval = sym->def[S_DEF_USER].val;
600 	size = strlen(newval) + 1;
601 	if (sym->type == S_HEX && (newval[0] != '0' || (newval[1] != 'x' && newval[1] != 'X'))) {
602 		size += 2;
603 		sym->def[S_DEF_USER].val = val = malloc(size);
604 		*val++ = '0';
605 		*val++ = 'x';
606 	} else if (!oldval || strcmp(oldval, newval))
607 		sym->def[S_DEF_USER].val = val = malloc(size);
608 	else
609 		return true;
610 
611 	strcpy(val, newval);
612 	free((void *)oldval);
613 	sym_clear_all_valid();
614 
615 	return true;
616 }
617 
618 const char *sym_get_string_value(struct symbol *sym)
619 {
620 	tristate val;
621 
622 	switch (sym->type) {
623 	case S_BOOLEAN:
624 	case S_TRISTATE:
625 		val = sym_get_tristate_value(sym);
626 		switch (val) {
627 		case no:
628 			return "n";
629 		case mod:
630 			return "m";
631 		case yes:
632 			return "y";
633 		}
634 		break;
635 	default:
636 		;
637 	}
638 	return (const char *)sym->curr.val;
639 }
640 
641 bool sym_is_changable(struct symbol *sym)
642 {
643 	return sym->visible > sym->rev_dep.tri;
644 }
645 
646 struct symbol *sym_lookup(const char *name, int isconst)
647 {
648 	struct symbol *symbol;
649 	const char *ptr;
650 	char *new_name;
651 	int hash = 0;
652 
653 	if (name) {
654 		if (name[0] && !name[1]) {
655 			switch (name[0]) {
656 			case 'y': return &symbol_yes;
657 			case 'm': return &symbol_mod;
658 			case 'n': return &symbol_no;
659 			}
660 		}
661 		for (ptr = name; *ptr; ptr++)
662 			hash += *ptr;
663 		hash &= 0xff;
664 
665 		for (symbol = symbol_hash[hash]; symbol; symbol = symbol->next) {
666 			if (!strcmp(symbol->name, name)) {
667 				if ((isconst && symbol->flags & SYMBOL_CONST) ||
668 				    (!isconst && !(symbol->flags & SYMBOL_CONST)))
669 					return symbol;
670 			}
671 		}
672 		new_name = strdup(name);
673 	} else {
674 		new_name = NULL;
675 		hash = 256;
676 	}
677 
678 	symbol = malloc(sizeof(*symbol));
679 	memset(symbol, 0, sizeof(*symbol));
680 	symbol->name = new_name;
681 	symbol->type = S_UNKNOWN;
682 	if (isconst)
683 		symbol->flags |= SYMBOL_CONST;
684 
685 	symbol->next = symbol_hash[hash];
686 	symbol_hash[hash] = symbol;
687 
688 	return symbol;
689 }
690 
691 struct symbol *sym_find(const char *name)
692 {
693 	struct symbol *symbol = NULL;
694 	const char *ptr;
695 	int hash = 0;
696 
697 	if (!name)
698 		return NULL;
699 
700 	if (name[0] && !name[1]) {
701 		switch (name[0]) {
702 		case 'y': return &symbol_yes;
703 		case 'm': return &symbol_mod;
704 		case 'n': return &symbol_no;
705 		}
706 	}
707 	for (ptr = name; *ptr; ptr++)
708 		hash += *ptr;
709 	hash &= 0xff;
710 
711 	for (symbol = symbol_hash[hash]; symbol; symbol = symbol->next) {
712 		if (!strcmp(symbol->name, name) &&
713 		    !(symbol->flags & SYMBOL_CONST))
714 				break;
715 	}
716 
717 	return symbol;
718 }
719 
720 struct symbol **sym_re_search(const char *pattern)
721 {
722 	struct symbol *sym, **sym_arr = NULL;
723 	int i, cnt, size;
724 	regex_t re;
725 
726 	cnt = size = 0;
727 	/* Skip if empty */
728 	if (strlen(pattern) == 0)
729 		return NULL;
730 	if (regcomp(&re, pattern, REG_EXTENDED|REG_NOSUB|REG_ICASE))
731 		return NULL;
732 
733 	for_all_symbols(i, sym) {
734 		if (sym->flags & SYMBOL_CONST || !sym->name)
735 			continue;
736 		if (regexec(&re, sym->name, 0, NULL, 0))
737 			continue;
738 		if (cnt + 1 >= size) {
739 			void *tmp = sym_arr;
740 			size += 16;
741 			sym_arr = realloc(sym_arr, size * sizeof(struct symbol *));
742 			if (!sym_arr) {
743 				free(tmp);
744 				return NULL;
745 			}
746 		}
747 		sym_arr[cnt++] = sym;
748 	}
749 	if (sym_arr)
750 		sym_arr[cnt] = NULL;
751 	regfree(&re);
752 
753 	return sym_arr;
754 }
755 
756 
757 struct symbol *sym_check_deps(struct symbol *sym);
758 
759 static struct symbol *sym_check_expr_deps(struct expr *e)
760 {
761 	struct symbol *sym;
762 
763 	if (!e)
764 		return NULL;
765 	switch (e->type) {
766 	case E_OR:
767 	case E_AND:
768 		sym = sym_check_expr_deps(e->left.expr);
769 		if (sym)
770 			return sym;
771 		return sym_check_expr_deps(e->right.expr);
772 	case E_NOT:
773 		return sym_check_expr_deps(e->left.expr);
774 	case E_EQUAL:
775 	case E_UNEQUAL:
776 		sym = sym_check_deps(e->left.sym);
777 		if (sym)
778 			return sym;
779 		return sym_check_deps(e->right.sym);
780 	case E_SYMBOL:
781 		return sym_check_deps(e->left.sym);
782 	default:
783 		break;
784 	}
785 	printf("Oops! How to check %d?\n", e->type);
786 	return NULL;
787 }
788 
789 /* return NULL when dependencies are OK */
790 struct symbol *sym_check_deps(struct symbol *sym)
791 {
792 	struct symbol *sym2;
793 	struct property *prop;
794 
795 	if (sym->flags & SYMBOL_CHECK) {
796 		fprintf(stderr, "%s:%d:error: found recursive dependency: %s",
797 		        sym->prop->file->name, sym->prop->lineno, sym->name);
798 		return sym;
799 	}
800 	if (sym->flags & SYMBOL_CHECKED)
801 		return NULL;
802 
803 	sym->flags |= (SYMBOL_CHECK | SYMBOL_CHECKED);
804 	sym2 = sym_check_expr_deps(sym->rev_dep.expr);
805 	if (sym2)
806 		goto out;
807 
808 	for (prop = sym->prop; prop; prop = prop->next) {
809 		if (prop->type == P_CHOICE || prop->type == P_SELECT)
810 			continue;
811 		sym2 = sym_check_expr_deps(prop->visible.expr);
812 		if (sym2)
813 			goto out;
814 		if (prop->type != P_DEFAULT || sym_is_choice(sym))
815 			continue;
816 		sym2 = sym_check_expr_deps(prop->expr);
817 		if (sym2)
818 			goto out;
819 	}
820 out:
821 	if (sym2)
822 		fprintf(stderr, " -> %s%s", sym->name, sym2 == sym? "\n": "");
823 	sym->flags &= ~SYMBOL_CHECK;
824 	return sym2;
825 }
826 
827 struct property *prop_alloc(enum prop_type type, struct symbol *sym)
828 {
829 	struct property *prop;
830 	struct property **propp;
831 
832 	prop = malloc(sizeof(*prop));
833 	memset(prop, 0, sizeof(*prop));
834 	prop->type = type;
835 	prop->sym = sym;
836 	prop->file = current_file;
837 	prop->lineno = zconf_lineno();
838 
839 	/* append property to the prop list of symbol */
840 	if (sym) {
841 		for (propp = &sym->prop; *propp; propp = &(*propp)->next)
842 			;
843 		*propp = prop;
844 	}
845 
846 	return prop;
847 }
848 
849 struct symbol *prop_get_symbol(struct property *prop)
850 {
851 	if (prop->expr && (prop->expr->type == E_SYMBOL ||
852 			   prop->expr->type == E_LIST))
853 		return prop->expr->left.sym;
854 	return NULL;
855 }
856 
857 const char *prop_get_type_name(enum prop_type type)
858 {
859 	switch (type) {
860 	case P_PROMPT:
861 		return "prompt";
862 	case P_ENV:
863 		return "env";
864 	case P_COMMENT:
865 		return "comment";
866 	case P_MENU:
867 		return "menu";
868 	case P_DEFAULT:
869 		return "default";
870 	case P_CHOICE:
871 		return "choice";
872 	case P_SELECT:
873 		return "select";
874 	case P_RANGE:
875 		return "range";
876 	case P_UNKNOWN:
877 		break;
878 	}
879 	return "unknown";
880 }
881 
882 void prop_add_env(const char *env)
883 {
884 	struct symbol *sym, *sym2;
885 	struct property *prop;
886 	char *p;
887 
888 	sym = current_entry->sym;
889 	sym->flags |= SYMBOL_AUTO;
890 	for_all_properties(sym, prop, P_ENV) {
891 		sym2 = prop_get_symbol(prop);
892 		if (strcmp(sym2->name, env))
893 			menu_warn(current_entry, "redefining environment symbol from %s",
894 				  sym2->name);
895 		return;
896 	}
897 
898 	prop = prop_alloc(P_ENV, sym);
899 	prop->expr = expr_alloc_symbol(sym_lookup(env, 1));
900 
901 	sym_env_list = expr_alloc_one(E_LIST, sym_env_list);
902 	sym_env_list->right.sym = sym;
903 
904 	p = getenv(env);
905 	if (p)
906 		sym_add_default(sym, p);
907 	else
908 		menu_warn(current_entry, "environment variable %s undefined", env);
909 }
910