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 {
 302                         if (sym->visible != no) {
 303                                 /* if the symbol is visible use the user value
 304                                  * if available, otherwise try the default value
 305                                  */
 306                                 sym->flags |= SYMBOL_WRITE;
 307                                 if (sym_has_value(sym)) {
 308                                         newval.tri = EXPR_AND(sym->def[S_DEF_USER].tri,
 309                                                               sym->visible);
 310                                         goto calc_newval;
 311                                 }
 312                         }
 313                         if (sym->rev_dep.tri != no)
 314                                 sym->flags |= SYMBOL_WRITE;
 315                         if (!sym_is_choice(sym)) {
 316                                 prop = sym_get_default_prop(sym);
 317                                 if (prop) {
 318                                         sym->flags |= SYMBOL_WRITE;
 319                                         newval.tri = EXPR_AND(expr_calc_value(prop->expr),
 320                                                               prop->visible.tri);
 321                                 }
 322                         }
 323                 calc_newval:
 324                         newval.tri = EXPR_OR(newval.tri, sym->rev_dep.tri);
 325                 }
 326                 if (newval.tri == mod && sym_get_type(sym) == S_BOOLEAN)
 327                         newval.tri = yes;
 328                 break;
 329         case S_STRING:
 330         case S_HEX:
 331         case S_INT:
 332                 if (sym->visible != no) {
 333                         sym->flags |= SYMBOL_WRITE;
 334                         if (sym_has_value(sym)) {
 335                                 newval.val = sym->def[S_DEF_USER].val;
 336                                 break;
 337                         }
 338                 }
 339                 prop = sym_get_default_prop(sym);
 340                 if (prop) {
 341                         struct symbol *ds = prop_get_symbol(prop);
 342                         if (ds) {
 343                                 sym->flags |= SYMBOL_WRITE;
 344                                 sym_calc_value(ds);
 345                                 newval.val = ds->curr.val;
 346                         }
 347                 }
 348                 break;
 349         default:
 350                 ;
 351         }
 352
 353         if (sym->flags & SYMBOL_AUTO)
 354                 sym->flags &= ~SYMBOL_WRITE;
 355
 356         sym->curr = newval;
 357         if (sym_is_choice(sym) && newval.tri == yes)
 358                 sym->curr.val = sym_calc_choice(sym);
 359         sym_validate_range(sym);
 360
 361         if (memcmp(&oldval, &sym->curr, sizeof(oldval))) {
 362                 sym_set_changed(sym);
 363                 if (modules_sym == sym) {
 364                         sym_set_all_changed();
 365                         modules_val = modules_sym->curr.tri;
 366                 }
 367         }
 368
 369         if (sym_is_choice(sym)) {
 370                 struct symbol *choice_sym;
 371                 int flags = sym->flags & (SYMBOL_CHANGED | SYMBOL_WRITE);
 372
 373                 prop = sym_get_choice_prop(sym);
 374                 expr_list_for_each_sym(prop->expr, e, choice_sym) {
 375                         choice_sym->flags |= flags;
 376                         if (flags & SYMBOL_CHANGED)
 377                                 sym_set_changed(choice_sym);
 378                 }
 379         }
 380 }
 381
 382 void sym_clear_all_valid(void)
 383 {
 384         struct symbol *sym;
 385         int i;
 386
 387         for_all_symbols(i, sym)
 388                 sym->flags &= ~SYMBOL_VALID;
 389         sym_add_change_count(1);
 390         if (modules_sym)
 391                 sym_calc_value(modules_sym);
 392 }
 393
 394 void sym_set_changed(struct symbol *sym)
 395 {
 396         struct property *prop;
 397
 398         sym->flags |= SYMBOL_CHANGED;
 399         for (prop = sym->prop; prop; prop = prop->next) {
 400                 if (prop->menu)
 401                         prop->menu->flags |= MENU_CHANGED;
 402         }
 403 }
 404
 405 void sym_set_all_changed(void)
 406 {
 407         struct symbol *sym;
 408         int i;
 409
 410         for_all_symbols(i, sym)
 411                 sym_set_changed(sym);
 412 }
 413
 414 bool sym_tristate_within_range(struct symbol *sym, tristate val)
 415 {
 416         int type = sym_get_type(sym);
 417
 418         if (sym->visible == no)
 419                 return false;
 420
 421         if (type != S_BOOLEAN && type != S_TRISTATE)
 422                 return false;
 423
 424         if (type == S_BOOLEAN && val == mod)
 425                 return false;
 426         if (sym->visible <= sym->rev_dep.tri)
 427                 return false;
 428         if (sym_is_choice_value(sym) && sym->visible == yes)
 429                 return val == yes;
 430         return val >= sym->rev_dep.tri && val <= sym->visible;
 431 }
 432
 433 bool sym_set_tristate_value(struct symbol *sym, tristate val)
 434 {
 435         tristate oldval = sym_get_tristate_value(sym);
 436
 437         if (oldval != val && !sym_tristate_within_range(sym, val))
 438                 return false;
 439
 440         if (!(sym->flags & SYMBOL_DEF_USER)) {
 441                 sym->flags |= SYMBOL_DEF_USER;
 442                 sym_set_changed(sym);
 443         }
 444         /*
 445          * setting a choice value also resets the new flag of the choice
 446          * symbol and all other choice values.
 447          */
 448         if (sym_is_choice_value(sym) && val == yes) {
 449                 struct symbol *cs = prop_get_symbol(sym_get_choice_prop(sym));
 450                 struct property *prop;
 451                 struct expr *e;
 452
 453                 cs->def[S_DEF_USER].val = sym;
 454                 cs->flags |= SYMBOL_DEF_USER;
 455                 prop = sym_get_choice_prop(cs);
 456                 for (e = prop->expr; e; e = e->left.expr) {
 457                         if (e->right.sym->visible != no)
 458                                 e->right.sym->flags |= SYMBOL_DEF_USER;
 459                 }
 460         }
 461
 462         sym->def[S_DEF_USER].tri = val;
 463         if (oldval != val)
 464                 sym_clear_all_valid();
 465
 466         return true;
 467 }
 468
 469 tristate sym_toggle_tristate_value(struct symbol *sym)
 470 {
 471         tristate oldval, newval;
 472
 473         oldval = newval = sym_get_tristate_value(sym);
 474         do {
 475                 switch (newval) {
 476                 case no:
 477                         newval = mod;
 478                         break;
 479                 case mod:
 480                         newval = yes;
 481                         break;
 482                 case yes:
 483                         newval = no;
 484                         break;
 485                 }
 486                 if (sym_set_tristate_value(sym, newval))
 487                         break;
 488         } while (oldval != newval);
 489         return newval;
 490 }
 491
 492 bool sym_string_valid(struct symbol *sym, const char *str)
 493 {
 494         signed char ch;
 495
 496         switch (sym->type) {
 497         case S_STRING:
 498                 return true;
 499         case S_INT:
 500                 ch = *str++;
 501                 if (ch == '-')
 502                         ch = *str++;
 503                 if (!isdigit(ch))
 504                         return false;
 505                 if (ch == '0' && *str != 0)
 506                         return false;
 507                 while ((ch = *str++)) {
 508                         if (!isdigit(ch))
 509                                 return false;
 510                 }
 511                 return true;
 512         case S_HEX:
 513                 if (str[0] == '0' && (str[1] == 'x' || str[1] == 'X'))
 514                         str += 2;
 515                 ch = *str++;
 516                 do {
 517                         if (!isxdigit(ch))
 518                                 return false;
 519                 } while ((ch = *str++));
 520                 return true;
 521         case S_BOOLEAN:
 522         case S_TRISTATE:
 523                 switch (str[0]) {
 524                 case 'y': case 'Y':
 525                 case 'm': case 'M':
 526                 case 'n': case 'N':
 527                         return true;
 528                 }
 529                 return false;
 530         default:
 531                 return false;
 532         }
 533 }
 534
 535 bool sym_string_within_range(struct symbol *sym, const char *str)
 536 {
 537         struct property *prop;
 538         int val;
 539
 540         switch (sym->type) {
 541         case S_STRING:
 542                 return sym_string_valid(sym, str);
 543         case S_INT:
 544                 if (!sym_string_valid(sym, str))
 545                         return false;
 546                 prop = sym_get_range_prop(sym);
 547                 if (!prop)
 548                         return true;
 549                 val = strtol(str, NULL, 10);
 550                 return val >= sym_get_range_val(prop->expr->left.sym, 10) &&
 551                        val <= sym_get_range_val(prop->expr->right.sym, 10);
 552         case S_HEX:
 553                 if (!sym_string_valid(sym, str))
 554                         return false;
 555                 prop = sym_get_range_prop(sym);
 556                 if (!prop)
 557                         return true;
 558                 val = strtol(str, NULL, 16);
 559                 return val >= sym_get_range_val(prop->expr->left.sym, 16) &&
 560                        val <= sym_get_range_val(prop->expr->right.sym, 16);
 561         case S_BOOLEAN:
 562         case S_TRISTATE:
 563                 switch (str[0]) {
 564                 case 'y': case 'Y':
 565                         return sym_tristate_within_range(sym, yes);
 566                 case 'm': case 'M':
 567                         return sym_tristate_within_range(sym, mod);
 568                 case 'n': case 'N':
 569                         return sym_tristate_within_range(sym, no);
 570                 }
 571                 return false;
 572         default:
 573                 return false;
 574         }
 575 }
 576
 577 bool sym_set_string_value(struct symbol *sym, const char *newval)
 578 {
 579         const char *oldval;
 580         char *val;
 581         int size;
 582
 583         switch (sym->type) {
 584         case S_BOOLEAN:
 585         case S_TRISTATE:
 586                 switch (newval[0]) {
 587                 case 'y': case 'Y':
 588                         return sym_set_tristate_value(sym, yes);
 589                 case 'm': case 'M':
 590                         return sym_set_tristate_value(sym, mod);
 591                 case 'n': case 'N':
 592                         return sym_set_tristate_value(sym, no);
 593                 }
 594                 return false;
 595         default:
 596                 ;
 597         }
 598
 599         if (!sym_string_within_range(sym, newval))
 600                 return false;
 601
 602         if (!(sym->flags & SYMBOL_DEF_USER)) {
 603                 sym->flags |= SYMBOL_DEF_USER;
 604                 sym_set_changed(sym);
 605         }
 606
 607         oldval = sym->def[S_DEF_USER].val;
 608         size = strlen(newval) + 1;
 609         if (sym->type == S_HEX && (newval[0] != '0' || (newval[1] != 'x' && newval[1] != 'X'))) {
 610                 size += 2;
 611                 sym->def[S_DEF_USER].val = val = malloc(size);
 612                 *val++ = '0';
 613                 *val++ = 'x';
 614         } else if (!oldval || strcmp(oldval, newval))
 615                 sym->def[S_DEF_USER].val = val = malloc(size);
 616         else
 617                 return true;
 618
 619         strcpy(val, newval);
 620         free((void *)oldval);
 621         sym_clear_all_valid();
 622
 623         return true;
 624 }
 625
 626 const char *sym_get_string_value(struct symbol *sym)
 627 {
 628         tristate val;
 629
 630         switch (sym->type) {
 631         case S_BOOLEAN:
 632         case S_TRISTATE:
 633                 val = sym_get_tristate_value(sym);
 634                 switch (val) {
 635                 case no:
 636                         return "n";
 637                 case mod:
 638                         return "m";
 639                 case yes:
 640                         return "y";
 641                 }
 642                 break;
 643         default:
 644                 ;
 645         }
 646         return (const char *)sym->curr.val;
 647 }
 648
 649 bool sym_is_changable(struct symbol *sym)
 650 {
 651         return sym->visible > sym->rev_dep.tri;
 652 }
 653
 654 struct symbol *sym_lookup(const char *name, int isconst)
 655 {
 656         struct symbol *symbol;
 657         const char *ptr;
 658         char *new_name;
 659         int hash = 0;
 660
 661         if (name) {
 662                 if (name[0] && !name[1]) {
 663                         switch (name[0]) {
 664                         case 'y': return &symbol_yes;
 665                         case 'm': return &symbol_mod;
 666                         case 'n': return &symbol_no;
 667                         }
 668                 }
 669                 for (ptr = name; *ptr; ptr++)
 670                         hash += *ptr;
 671                 hash &= 0xff;
 672
 673                 for (symbol = symbol_hash[hash]; symbol; symbol = symbol->next) {
 674                         if (!strcmp(symbol->name, name)) {
 675                                 if ((isconst && symbol->flags & SYMBOL_CONST) ||
 676                                     (!isconst && !(symbol->flags & SYMBOL_CONST)))
 677                                         return symbol;
 678                         }
 679                 }
 680                 new_name = strdup(name);
 681         } else {
 682                 new_name = NULL;
 683                 hash = 256;
 684         }
 685
 686         symbol = malloc(sizeof(*symbol));
 687         memset(symbol, 0, sizeof(*symbol));
 688         symbol->name = new_name;
 689         symbol->type = S_UNKNOWN;
 690         if (isconst)
 691                 symbol->flags |= SYMBOL_CONST;
 692
 693         symbol->next = symbol_hash[hash];
 694         symbol_hash[hash] = symbol;
 695
 696         return symbol;
 697 }
 698
 699 struct symbol *sym_find(const char *name)
 700 {
 701         struct symbol *symbol = NULL;
 702         const char *ptr;
 703         int hash = 0;
 704
 705         if (!name)
 706                 return NULL;
 707
 708         if (name[0] && !name[1]) {
 709                 switch (name[0]) {
 710                 case 'y': return &symbol_yes;
 711                 case 'm': return &symbol_mod;
 712                 case 'n': return &symbol_no;
 713                 }
 714         }
 715         for (ptr = name; *ptr; ptr++)
 716                 hash += *ptr;
 717         hash &= 0xff;
 718
 719         for (symbol = symbol_hash[hash]; symbol; symbol = symbol->next) {
 720                 if (!strcmp(symbol->name, name) &&
 721                     !(symbol->flags & SYMBOL_CONST))
 722                                 break;
 723         }
 724
 725         return symbol;
 726 }
 727
 728 struct symbol **sym_re_search(const char *pattern)
 729 {
 730         struct symbol *sym, **sym_arr = NULL;
 731         int i, cnt, size;
 732         regex_t re;
 733
 734         cnt = size = 0;
 735         /* Skip if empty */
 736         if (strlen(pattern) == 0)
 737                 return NULL;
 738         if (regcomp(&re, pattern, REG_EXTENDED|REG_NOSUB|REG_ICASE))
 739                 return NULL;
 740
 741         for_all_symbols(i, sym) {
 742                 if (sym->flags & SYMBOL_CONST || !sym->name)
 743                         continue;
 744                 if (regexec(&re, sym->name, 0, NULL, 0))
 745                         continue;
 746                 if (cnt + 1 >= size) {
 747                         void *tmp = sym_arr;
 748                         size += 16;
 749                         sym_arr = realloc(sym_arr, size * sizeof(struct symbol *));
 750                         if (!sym_arr) {
 751                                 free(tmp);
 752                                 return NULL;
 753                         }
 754                 }
 755                 sym_arr[cnt++] = sym;
 756         }
 757         if (sym_arr)
 758                 sym_arr[cnt] = NULL;
 759         regfree(&re);
 760
 761         return sym_arr;
 762 }
 763
 764
 765 struct symbol *sym_check_deps(struct symbol *sym);
 766
 767 static struct symbol *sym_check_expr_deps(struct expr *e)
 768 {
 769         struct symbol *sym;
 770
 771         if (!e)
 772                 return NULL;
 773         switch (e->type) {
 774         case E_OR:
 775         case E_AND:
 776                 sym = sym_check_expr_deps(e->left.expr);
 777                 if (sym)
 778                         return sym;
 779                 return sym_check_expr_deps(e->right.expr);
 780         case E_NOT:
 781                 return sym_check_expr_deps(e->left.expr);
 782         case E_EQUAL:
 783         case E_UNEQUAL:
 784                 sym = sym_check_deps(e->left.sym);
 785                 if (sym)
 786                         return sym;
 787                 return sym_check_deps(e->right.sym);
 788         case E_SYMBOL:
 789                 return sym_check_deps(e->left.sym);
 790         default:
 791                 break;
 792         }
 793         printf("Oops! How to check %d?\n", e->type);
 794         return NULL;
 795 }
 796
 797 /* return NULL when dependencies are OK */
 798 struct symbol *sym_check_deps(struct symbol *sym)
 799 {
 800         struct symbol *sym2;
 801         struct property *prop;
 802
 803         if (sym->flags & SYMBOL_CHECK) {
 804                 fprintf(stderr, "%s:%d:error: found recursive dependency: %s",
 805                         sym->prop->file->name, sym->prop->lineno, sym->name);
 806                 return sym;
 807         }
 808         if (sym->flags & SYMBOL_CHECKED)
 809                 return NULL;
 810
 811         sym->flags |= (SYMBOL_CHECK | SYMBOL_CHECKED);
 812         sym2 = sym_check_expr_deps(sym->rev_dep.expr);
 813         if (sym2)
 814                 goto out;
 815
 816         for (prop = sym->prop; prop; prop = prop->next) {
 817                 if (prop->type == P_CHOICE || prop->type == P_SELECT)
 818                         continue;
 819                 sym2 = sym_check_expr_deps(prop->visible.expr);
 820                 if (sym2)
 821                         goto out;
 822                 if (prop->type != P_DEFAULT || sym_is_choice(sym))
 823                         continue;
 824                 sym2 = sym_check_expr_deps(prop->expr);
 825                 if (sym2)
 826                         goto out;
 827         }
 828 out:
 829         if (sym2)
 830                 fprintf(stderr, " -> %s%s", sym->name, sym2 == sym? "\n": "");
 831         sym->flags &= ~SYMBOL_CHECK;
 832         return sym2;
 833 }
 834
 835 struct property *prop_alloc(enum prop_type type, struct symbol *sym)
 836 {
 837         struct property *prop;
 838         struct property **propp;
 839
 840         prop = malloc(sizeof(*prop));
 841         memset(prop, 0, sizeof(*prop));
 842         prop->type = type;
 843         prop->sym = sym;
 844         prop->file = current_file;
 845         prop->lineno = zconf_lineno();
 846
 847         /* append property to the prop list of symbol */
 848         if (sym) {
 849                 for (propp = &sym->prop; *propp; propp = &(*propp)->next)
 850                         ;
 851                 *propp = prop;
 852         }
 853
 854         return prop;
 855 }
 856
 857 struct symbol *prop_get_symbol(struct property *prop)
 858 {
 859         if (prop->expr && (prop->expr->type == E_SYMBOL ||
 860                            prop->expr->type == E_LIST))
 861                 return prop->expr->left.sym;
 862         return NULL;
 863 }
 864
 865 const char *prop_get_type_name(enum prop_type type)
 866 {
 867         switch (type) {
 868         case P_PROMPT:
 869                 return "prompt";
 870         case P_ENV:
 871                 return "env";
 872         case P_COMMENT:
 873                 return "comment";
 874         case P_MENU:
 875                 return "menu";
 876         case P_DEFAULT:
 877                 return "default";
 878         case P_CHOICE:
 879                 return "choice";
 880         case P_SELECT:
 881                 return "select";
 882         case P_RANGE:
 883                 return "range";
 884         case P_UNKNOWN:
 885                 break;
 886         }
 887         return "unknown";
 888 }
 889
 890 void prop_add_env(const char *env)
 891 {
 892         struct symbol *sym, *sym2;
 893         struct property *prop;
 894         char *p;
 895
 896         sym = current_entry->sym;
 897         sym->flags |= SYMBOL_AUTO;
 898         for_all_properties(sym, prop, P_ENV) {
 899                 sym2 = prop_get_symbol(prop);
 900                 if (strcmp(sym2->name, env))
 901                         menu_warn(current_entry, "redefining environment symbol from %s",
 902                                   sym2->name);
 903                 return;
 904         }
 905
 906         prop = prop_alloc(P_ENV, sym);
 907         prop->expr = expr_alloc_symbol(sym_lookup(env, 1));
 908
 909         sym_env_list = expr_alloc_one(E_LIST, sym_env_list);
 910         sym_env_list->right.sym = sym;
 911
 912         p = getenv(env);
 913         if (p)
 914                 sym_add_default(sym, p);
 915         else
 916                 menu_warn(current_entry, "environment variable %s undefined", env);
 917 }