scripts/kconfig/symbol.c

   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 }