scripts/kconfig/confdata.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2002 Roman Zippel <[email protected]>
   4  */
   5
   6 #include <sys/mman.h>
   7 #include <sys/stat.h>
   8 #include <sys/types.h>
   9 #include <ctype.h>
  10 #include <errno.h>
  11 #include <fcntl.h>
  12 #include <limits.h>
  13 #include <stdarg.h>
  14 #include <stdbool.h>
  15 #include <stdio.h>
  16 #include <stdlib.h>
  17 #include <string.h>
  18 #include <time.h>
  19 #include <unistd.h>
  20
  21 #include "internal.h"
  22 #include "lkc.h"
  23
  24 struct gstr autoconf_cmd;
  25
  26 /* return true if 'path' exists, false otherwise */
  27 static bool is_present(const char *path)
  28 {
  29         struct stat st;
  30
  31         return !stat(path, &st);
  32 }
  33
  34 /* return true if 'path' exists and it is a directory, false otherwise */
  35 static bool is_dir(const char *path)
  36 {
  37         struct stat st;
  38
  39         if (stat(path, &st))
  40                 return false;
  41
  42         return S_ISDIR(st.st_mode);
  43 }
  44
  45 /* return true if the given two files are the same, false otherwise */
  46 static bool is_same(const char *file1, const char *file2)
  47 {
  48         int fd1, fd2;
  49         struct stat st1, st2;
  50         void *map1, *map2;
  51         bool ret = false;
  52
  53         fd1 = open(file1, O_RDONLY);
  54         if (fd1 < 0)
  55                 return ret;
  56
  57         fd2 = open(file2, O_RDONLY);
  58         if (fd2 < 0)
  59                 goto close1;
  60
  61         ret = fstat(fd1, &st1);
  62         if (ret)
  63                 goto close2;
  64         ret = fstat(fd2, &st2);
  65         if (ret)
  66                 goto close2;
  67
  68         if (st1.st_size != st2.st_size)
  69                 goto close2;
  70
  71         map1 = mmap(NULL, st1.st_size, PROT_READ, MAP_PRIVATE, fd1, 0);
  72         if (map1 == MAP_FAILED)
  73                 goto close2;
  74
  75         map2 = mmap(NULL, st2.st_size, PROT_READ, MAP_PRIVATE, fd2, 0);
  76         if (map2 == MAP_FAILED)
  77                 goto close2;
  78
  79         if (bcmp(map1, map2, st1.st_size))
  80                 goto close2;
  81
  82         ret = true;
  83 close2:
  84         close(fd2);
  85 close1:
  86         close(fd1);
  87
  88         return ret;
  89 }
  90
  91 /*
  92  * Create the parent directory of the given path.
  93  *
  94  * For example, if 'include/config/auto.conf' is given, create 'include/config'.
  95  */
  96 static int make_parent_dir(const char *path)
  97 {
  98         char tmp[PATH_MAX + 1];
  99         char *p;
 100
 101         strncpy(tmp, path, sizeof(tmp));
 102         tmp[sizeof(tmp) - 1] = 0;
 103
 104         /* Remove the base name. Just return if nothing is left */
 105         p = strrchr(tmp, '/');
 106         if (!p)
 107                 return 0;
 108         *(p + 1) = 0;
 109
 110         /* Just in case it is an absolute path */
 111         p = tmp;
 112         while (*p == '/')
 113                 p++;
 114
 115         while ((p = strchr(p, '/'))) {
 116                 *p = 0;
 117
 118                 /* skip if the directory exists */
 119                 if (!is_dir(tmp) && mkdir(tmp, 0755))
 120                         return -1;
 121
 122                 *p = '/';
 123                 while (*p == '/')
 124                         p++;
 125         }
 126
 127         return 0;
 128 }
 129
 130 static char depfile_path[PATH_MAX];
 131 static size_t depfile_prefix_len;
 132
 133 /* touch depfile for symbol 'name' */
 134 static int conf_touch_dep(const char *name)
 135 {
 136         int fd;
 137
 138         /* check overflow: prefix + name + '\0' must fit in buffer. */
 139         if (depfile_prefix_len + strlen(name) + 1 > sizeof(depfile_path))
 140                 return -1;
 141
 142         strcpy(depfile_path + depfile_prefix_len, name);
 143
 144         fd = open(depfile_path, O_WRONLY | O_CREAT | O_TRUNC, 0644);
 145         if (fd == -1)
 146                 return -1;
 147         close(fd);
 148
 149         return 0;
 150 }
 151
 152 static void conf_warning(const char *fmt, ...)
 153         __attribute__ ((format (printf, 1, 2)));
 154
 155 static void conf_message(const char *fmt, ...)
 156         __attribute__ ((format (printf, 1, 2)));
 157
 158 static const char *conf_filename;
 159 static int conf_lineno, conf_warnings;
 160
 161 bool conf_errors(void)
 162 {
 163         if (conf_warnings)
 164                 return getenv("KCONFIG_WERROR");
 165         return false;
 166 }
 167
 168 static void conf_warning(const char *fmt, ...)
 169 {
 170         va_list ap;
 171         va_start(ap, fmt);
 172         fprintf(stderr, "%s:%d:warning: ", conf_filename, conf_lineno);
 173         vfprintf(stderr, fmt, ap);
 174         fprintf(stderr, "\n");
 175         va_end(ap);
 176         conf_warnings++;
 177 }
 178
 179 static void conf_default_message_callback(const char *s)
 180 {
 181         printf("#\n# ");
 182         printf("%s", s);
 183         printf("\n#\n");
 184 }
 185
 186 static void (*conf_message_callback)(const char *s) =
 187         conf_default_message_callback;
 188 void conf_set_message_callback(void (*fn)(const char *s))
 189 {
 190         conf_message_callback = fn;
 191 }
 192
 193 static void conf_message(const char *fmt, ...)
 194 {
 195         va_list ap;
 196         char buf[4096];
 197
 198         if (!conf_message_callback)
 199                 return;
 200
 201         va_start(ap, fmt);
 202
 203         vsnprintf(buf, sizeof(buf), fmt, ap);
 204         conf_message_callback(buf);
 205         va_end(ap);
 206 }
 207
 208 const char *conf_get_configname(void)
 209 {
 210         char *name = getenv("KCONFIG_CONFIG");
 211
 212         return name ? name : ".config";
 213 }
 214
 215 static const char *conf_get_autoconfig_name(void)
 216 {
 217         char *name = getenv("KCONFIG_AUTOCONFIG");
 218
 219         return name ? name : "include/config/auto.conf";
 220 }
 221
 222 static const char *conf_get_autoheader_name(void)
 223 {
 224         char *name = getenv("KCONFIG_AUTOHEADER");
 225
 226         return name ? name : "include/generated/autoconf.h";
 227 }
 228
 229 static const char *conf_get_rustccfg_name(void)
 230 {
 231         char *name = getenv("KCONFIG_RUSTCCFG");
 232
 233         return name ? name : "include/generated/rustc_cfg";
 234 }
 235
 236 static int conf_set_sym_val(struct symbol *sym, int def, int def_flags, char *p)
 237 {
 238         char *p2;
 239
 240         switch (sym->type) {
 241         case S_TRISTATE:
 242                 if (p[0] == 'm') {
 243                         sym->def[def].tri = mod;
 244                         sym->flags |= def_flags;
 245                         break;
 246                 }
 247                 /* fall through */
 248         case S_BOOLEAN:
 249                 if (p[0] == 'y') {
 250                         sym->def[def].tri = yes;
 251                         sym->flags |= def_flags;
 252                         break;
 253                 }
 254                 if (p[0] == 'n') {
 255                         sym->def[def].tri = no;
 256                         sym->flags |= def_flags;
 257                         break;
 258                 }
 259                 if (def != S_DEF_AUTO)
 260                         conf_warning("symbol value '%s' invalid for %s",
 261                                      p, sym->name);
 262                 return 1;
 263         case S_STRING:
 264                 /* No escaping for S_DEF_AUTO (include/config/auto.conf) */
 265                 if (def != S_DEF_AUTO) {
 266                         if (*p++ != '"')
 267                                 break;
 268                         for (p2 = p; (p2 = strpbrk(p2, "\"\\")); p2++) {
 269                                 if (*p2 == '"') {
 270                                         *p2 = 0;
 271                                         break;
 272                                 }
 273                                 memmove(p2, p2 + 1, strlen(p2));
 274                         }
 275                         if (!p2) {
 276                                 conf_warning("invalid string found");
 277                                 return 1;
 278                         }
 279                 }
 280                 /* fall through */
 281         case S_INT:
 282         case S_HEX:
 283                 if (sym_string_valid(sym, p)) {
 284                         sym->def[def].val = xstrdup(p);
 285                         sym->flags |= def_flags;
 286                 } else {
 287                         if (def != S_DEF_AUTO)
 288                                 conf_warning("symbol value '%s' invalid for %s",
 289                                              p, sym->name);
 290                         return 1;
 291                 }
 292                 break;
 293         default:
 294                 ;
 295         }
 296         return 0;
 297 }
 298
 299 /* like getline(), but the newline character is stripped away */
 300 static ssize_t getline_stripped(char **lineptr, size_t *n, FILE *stream)
 301 {
 302         ssize_t len;
 303
 304         len = getline(lineptr, n, stream);
 305
 306         if (len > 0 && (*lineptr)[len - 1] == '\n') {
 307                 len--;
 308                 (*lineptr)[len] = '\0';
 309
 310                 if (len > 0 && (*lineptr)[len - 1] == '\r') {
 311                         len--;
 312                         (*lineptr)[len] = '\0';
 313                 }
 314         }
 315
 316         return len;
 317 }
 318
 319 int conf_read_simple(const char *name, int def)
 320 {
 321         FILE *in = NULL;
 322         char   *line = NULL;
 323         size_t  line_asize = 0;
 324         char *p, *val;
 325         struct symbol *sym;
 326         int def_flags;
 327         const char *warn_unknown, *sym_name;
 328
 329         warn_unknown = getenv("KCONFIG_WARN_UNKNOWN_SYMBOLS");
 330         if (name) {
 331                 in = zconf_fopen(name);
 332         } else {
 333                 char *env;
 334
 335                 name = conf_get_configname();
 336                 in = zconf_fopen(name);
 337                 if (in)
 338                         goto load;
 339                 conf_set_changed(true);
 340
 341                 env = getenv("KCONFIG_DEFCONFIG_LIST");
 342                 if (!env)
 343                         return 1;
 344
 345                 while (1) {
 346                         bool is_last;
 347
 348                         while (isspace(*env))
 349                                 env++;
 350
 351                         if (!*env)
 352                                 break;
 353
 354                         p = env;
 355                         while (*p && !isspace(*p))
 356                                 p++;
 357
 358                         is_last = (*p == '\0');
 359
 360                         *p = '\0';
 361
 362                         in = zconf_fopen(env);
 363                         if (in) {
 364                                 conf_message("using defaults found in %s",
 365                                              env);
 366                                 goto load;
 367                         }
 368
 369                         if (is_last)
 370                                 break;
 371
 372                         env = p + 1;
 373                 }
 374         }
 375         if (!in)
 376                 return 1;
 377
 378 load:
 379         conf_filename = name;
 380         conf_lineno = 0;
 381         conf_warnings = 0;
 382
 383         def_flags = SYMBOL_DEF << def;
 384         for_all_symbols(sym) {
 385                 sym->flags &= ~(def_flags|SYMBOL_VALID);
 386                 switch (sym->type) {
 387                 case S_INT:
 388                 case S_HEX:
 389                 case S_STRING:
 390                         free(sym->def[def].val);
 391                         /* fall through */
 392                 default:
 393                         sym->def[def].val = NULL;
 394                         sym->def[def].tri = no;
 395                 }
 396         }
 397
 398         while (getline_stripped(&line, &line_asize, in) != -1) {
 399                 struct menu *choice;
 400
 401                 conf_lineno++;
 402
 403                 if (!line[0]) /* blank line */
 404                         continue;
 405
 406                 if (line[0] == '#') {
 407                         if (line[1] != ' ')
 408                                 continue;
 409                         p = line + 2;
 410                         if (memcmp(p, CONFIG_, strlen(CONFIG_)))
 411                                 continue;
 412                         sym_name = p + strlen(CONFIG_);
 413                         p = strchr(sym_name, ' ');
 414                         if (!p)
 415                                 continue;
 416                         *p++ = 0;
 417                         if (strcmp(p, "is not set"))
 418                                 continue;
 419
 420                         val = "n";
 421                 } else {
 422                         if (memcmp(line, CONFIG_, strlen(CONFIG_))) {
 423                                 conf_warning("unexpected data: %s", line);
 424                                 continue;
 425                         }
 426
 427                         sym_name = line + strlen(CONFIG_);
 428                         p = strchr(sym_name, '=');
 429                         if (!p) {
 430                                 conf_warning("unexpected data: %s", line);
 431                                 continue;
 432                         }
 433                         *p = 0;
 434                         val = p + 1;
 435                 }
 436
 437                 sym = sym_find(sym_name);
 438                 if (!sym) {
 439                         if (def == S_DEF_AUTO) {
 440                                 /*
 441                                  * Reading from include/config/auto.conf.
 442                                  * If CONFIG_FOO previously existed in auto.conf
 443                                  * but it is missing now, include/config/FOO
 444                                  * must be touched.
 445                                  */
 446                                 conf_touch_dep(sym_name);
 447                         } else {
 448                                 if (warn_unknown)
 449                                         conf_warning("unknown symbol: %s", sym_name);
 450
 451                                 conf_set_changed(true);
 452                         }
 453                         continue;
 454                 }
 455
 456                 if (sym->flags & def_flags)
 457                         conf_warning("override: reassigning to symbol %s", sym->name);
 458
 459                 if (conf_set_sym_val(sym, def, def_flags, val))
 460                         continue;
 461
 462                 /*
 463                  * If this is a choice member, give it the highest priority.
 464                  * If conflicting CONFIG options are given from an input file,
 465                  * the last one wins.
 466                  */
 467                 choice = sym_get_choice_menu(sym);
 468                 if (choice)
 469                         list_move(&sym->choice_link, &choice->choice_members);
 470         }
 471         free(line);
 472         fclose(in);
 473
 474         return 0;
 475 }
 476
 477 int conf_read(const char *name)
 478 {
 479         struct symbol *sym;
 480
 481         conf_set_changed(false);
 482
 483         if (conf_read_simple(name, S_DEF_USER)) {
 484                 sym_calc_value(modules_sym);
 485                 return 1;
 486         }
 487
 488         sym_calc_value(modules_sym);
 489
 490         for_all_symbols(sym) {
 491                 sym_calc_value(sym);
 492                 if (sym_is_choice(sym))
 493                         continue;
 494                 if (sym_has_value(sym) && (sym->flags & SYMBOL_WRITE)) {
 495                         /* check that calculated value agrees with saved value */
 496                         switch (sym->type) {
 497                         case S_BOOLEAN:
 498                         case S_TRISTATE:
 499                                 if (sym->def[S_DEF_USER].tri == sym_get_tristate_value(sym))
 500                                         continue;
 501                                 break;
 502                         default:
 503                                 if (!strcmp(sym->curr.val, sym->def[S_DEF_USER].val))
 504                                         continue;
 505                                 break;
 506                         }
 507                 } else if (!sym_has_value(sym) && !(sym->flags & SYMBOL_WRITE))
 508                         /* no previous value and not saved */
 509                         continue;
 510                 conf_set_changed(true);
 511                 /* maybe print value in verbose mode... */
 512         }
 513
 514         if (conf_warnings)
 515                 conf_set_changed(true);
 516
 517         return 0;
 518 }
 519
 520 struct comment_style {
 521         const char *decoration;
 522         const char *prefix;
 523         const char *postfix;
 524 };
 525
 526 static const struct comment_style comment_style_pound = {
 527         .decoration = "#",
 528         .prefix = "#",
 529         .postfix = "#",
 530 };
 531
 532 static const struct comment_style comment_style_c = {
 533         .decoration = " *",
 534         .prefix = "/*",
 535         .postfix = " */",
 536 };
 537
 538 static void conf_write_heading(FILE *fp, const struct comment_style *cs)
 539 {
 540         if (!cs)
 541                 return;
 542
 543         fprintf(fp, "%s\n", cs->prefix);
 544
 545         fprintf(fp, "%s Automatically generated file; DO NOT EDIT.\n",
 546                 cs->decoration);
 547
 548         fprintf(fp, "%s %s\n", cs->decoration, rootmenu.prompt->text);
 549
 550         fprintf(fp, "%s\n", cs->postfix);
 551 }
 552
 553 /* The returned pointer must be freed on the caller side */
 554 static char *escape_string_value(const char *in)
 555 {
 556         const char *p;
 557         char *out;
 558         size_t len;
 559
 560         len = strlen(in) + strlen("\"\"") + 1;
 561
 562         p = in;
 563         while (1) {
 564                 p += strcspn(p, "\"\\");
 565
 566                 if (p[0] == '\0')
 567                         break;
 568
 569                 len++;
 570                 p++;
 571         }
 572
 573         out = xmalloc(len);
 574         out[0] = '\0';
 575
 576         strcat(out, "\"");
 577
 578         p = in;
 579         while (1) {
 580                 len = strcspn(p, "\"\\");
 581                 strncat(out, p, len);
 582                 p += len;
 583
 584                 if (p[0] == '\0')
 585                         break;
 586
 587                 strcat(out, "\\");
 588                 strncat(out, p++, 1);
 589         }
 590
 591         strcat(out, "\"");
 592
 593         return out;
 594 }
 595
 596 enum output_n { OUTPUT_N, OUTPUT_N_AS_UNSET, OUTPUT_N_NONE };
 597
 598 static void __print_symbol(FILE *fp, struct symbol *sym, enum output_n output_n,
 599                            bool escape_string)
 600 {
 601         const char *val;
 602         char *escaped = NULL;
 603
 604         if (sym->type == S_UNKNOWN)
 605                 return;
 606
 607         val = sym_get_string_value(sym);
 608
 609         if ((sym->type == S_BOOLEAN || sym->type == S_TRISTATE) &&
 610             output_n != OUTPUT_N && *val == 'n') {
 611                 if (output_n == OUTPUT_N_AS_UNSET)
 612                         fprintf(fp, "# %s%s is not set\n", CONFIG_, sym->name);
 613                 return;
 614         }
 615
 616         if (sym->type == S_STRING && escape_string) {
 617                 escaped = escape_string_value(val);
 618                 val = escaped;
 619         }
 620
 621         fprintf(fp, "%s%s=%s\n", CONFIG_, sym->name, val);
 622
 623         free(escaped);
 624 }
 625
 626 static void print_symbol_for_dotconfig(FILE *fp, struct symbol *sym)
 627 {
 628         __print_symbol(fp, sym, OUTPUT_N_AS_UNSET, true);
 629 }
 630
 631 static void print_symbol_for_autoconf(FILE *fp, struct symbol *sym)
 632 {
 633         __print_symbol(fp, sym, OUTPUT_N_NONE, false);
 634 }
 635
 636 void print_symbol_for_listconfig(struct symbol *sym)
 637 {
 638         __print_symbol(stdout, sym, OUTPUT_N, true);
 639 }
 640
 641 static void print_symbol_for_c(FILE *fp, struct symbol *sym)
 642 {
 643         const char *val;
 644         const char *sym_suffix = "";
 645         const char *val_prefix = "";
 646         char *escaped = NULL;
 647
 648         if (sym->type == S_UNKNOWN)
 649                 return;
 650
 651         val = sym_get_string_value(sym);
 652
 653         switch (sym->type) {
 654         case S_BOOLEAN:
 655         case S_TRISTATE:
 656                 switch (*val) {
 657                 case 'n':
 658                         return;
 659                 case 'm':
 660                         sym_suffix = "_MODULE";
 661                         /* fall through */
 662                 default:
 663                         val = "1";
 664                 }
 665                 break;
 666         case S_HEX:
 667                 if (val[0] != '0' || (val[1] != 'x' && val[1] != 'X'))
 668                         val_prefix = "0x";
 669                 break;
 670         case S_STRING:
 671                 escaped = escape_string_value(val);
 672                 val = escaped;
 673         default:
 674                 break;
 675         }
 676
 677         fprintf(fp, "#define %s%s%s %s%s\n", CONFIG_, sym->name, sym_suffix,
 678                 val_prefix, val);
 679
 680         free(escaped);
 681 }
 682
 683 static void print_symbol_for_rustccfg(FILE *fp, struct symbol *sym)
 684 {
 685         const char *val;
 686         const char *val_prefix = "";
 687         char *val_prefixed = NULL;
 688         size_t val_prefixed_len;
 689         char *escaped = NULL;
 690
 691         if (sym->type == S_UNKNOWN)
 692                 return;
 693
 694         val = sym_get_string_value(sym);
 695
 696         switch (sym->type) {
 697         case S_BOOLEAN:
 698         case S_TRISTATE:
 699                 /*
 700                  * We do not care about disabled ones, i.e. no need for
 701                  * what otherwise are "comments" in other printers.
 702                  */
 703                 if (*val == 'n')
 704                         return;
 705
 706                 /*
 707                  * To have similar functionality to the C macro `IS_ENABLED()`
 708                  * we provide an empty `--cfg CONFIG_X` here in both `y`
 709                  * and `m` cases.
 710                  *
 711                  * Then, the common `fprintf()` below will also give us
 712                  * a `--cfg CONFIG_X="y"` or `--cfg CONFIG_X="m"`, which can
 713                  * be used as the equivalent of `IS_BUILTIN()`/`IS_MODULE()`.
 714                  */
 715                 fprintf(fp, "--cfg=%s%s\n", CONFIG_, sym->name);
 716                 break;
 717         case S_HEX:
 718                 if (val[0] != '0' || (val[1] != 'x' && val[1] != 'X'))
 719                         val_prefix = "0x";
 720                 break;
 721         default:
 722                 break;
 723         }
 724
 725         if (strlen(val_prefix) > 0) {
 726                 val_prefixed_len = strlen(val) + strlen(val_prefix) + 1;
 727                 val_prefixed = xmalloc(val_prefixed_len);
 728                 snprintf(val_prefixed, val_prefixed_len, "%s%s", val_prefix, val);
 729                 val = val_prefixed;
 730         }
 731
 732         /* All values get escaped: the `--cfg` option only takes strings */
 733         escaped = escape_string_value(val);
 734         val = escaped;
 735
 736         fprintf(fp, "--cfg=%s%s=%s\n", CONFIG_, sym->name, val);
 737
 738         free(escaped);
 739         free(val_prefixed);
 740 }
 741
 742 /*
 743  * Write out a minimal config.
 744  * All values that has default values are skipped as this is redundant.
 745  */
 746 int conf_write_defconfig(const char *filename)
 747 {
 748         struct symbol *sym;
 749         struct menu *menu;
 750         FILE *out;
 751
 752         out = fopen(filename, "w");
 753         if (!out)
 754                 return 1;
 755
 756         sym_clear_all_valid();
 757
 758         menu_for_each_entry(menu) {
 759                 struct menu *choice;
 760
 761                 sym = menu->sym;
 762
 763                 if (!sym || sym_is_choice(sym))
 764                         continue;
 765
 766                 sym_calc_value(sym);
 767                 if (!(sym->flags & SYMBOL_WRITE))
 768                         continue;
 769                 sym->flags &= ~SYMBOL_WRITE;
 770                 /* Skip unchangeable symbols */
 771                 if (!sym_is_changeable(sym))
 772                         continue;
 773                 /* Skip symbols that are equal to the default */
 774                 if (!strcmp(sym_get_string_value(sym), sym_get_string_default(sym)))
 775                         continue;
 776
 777                 /* Skip choice values that are equal to the default */
 778                 choice = sym_get_choice_menu(sym);
 779                 if (choice) {
 780                         struct symbol *ds;
 781
 782                         ds = sym_choice_default(choice);
 783                         if (sym == ds && sym_get_tristate_value(sym) == yes)
 784                                 continue;
 785                 }
 786                 print_symbol_for_dotconfig(out, sym);
 787         }
 788         fclose(out);
 789         return 0;
 790 }
 791
 792 int conf_write(const char *name)
 793 {
 794         FILE *out;
 795         struct symbol *sym;
 796         struct menu *menu;
 797         const char *str;
 798         char tmpname[PATH_MAX + 1], oldname[PATH_MAX + 1];
 799         char *env;
 800         bool need_newline = false;
 801
 802         if (!name)
 803                 name = conf_get_configname();
 804
 805         if (!*name) {
 806                 fprintf(stderr, "config name is empty\n");
 807                 return -1;
 808         }
 809
 810         if (is_dir(name)) {
 811                 fprintf(stderr, "%s: Is a directory\n", name);
 812                 return -1;
 813         }
 814
 815         if (make_parent_dir(name))
 816                 return -1;
 817
 818         env = getenv("KCONFIG_OVERWRITECONFIG");
 819         if (env && *env) {
 820                 *tmpname = 0;
 821                 out = fopen(name, "w");
 822         } else {
 823                 snprintf(tmpname, sizeof(tmpname), "%s.%d.tmp",
 824                          name, (int)getpid());
 825                 out = fopen(tmpname, "w");
 826         }
 827         if (!out)
 828                 return 1;
 829
 830         conf_write_heading(out, &comment_style_pound);
 831
 832         if (!conf_get_changed())
 833                 sym_clear_all_valid();
 834
 835         menu = rootmenu.list;
 836         while (menu) {
 837                 sym = menu->sym;
 838                 if (!sym) {
 839                         if (!menu_is_visible(menu))
 840                                 goto next;
 841                         str = menu_get_prompt(menu);
 842                         fprintf(out, "\n"
 843                                      "#\n"
 844                                      "# %s\n"
 845                                      "#\n", str);
 846                         need_newline = false;
 847                 } else if (!sym_is_choice(sym) &&
 848                            !(sym->flags & SYMBOL_WRITTEN)) {
 849                         sym_calc_value(sym);
 850                         if (!(sym->flags & SYMBOL_WRITE))
 851                                 goto next;
 852                         if (need_newline) {
 853                                 fprintf(out, "\n");
 854                                 need_newline = false;
 855                         }
 856                         sym->flags |= SYMBOL_WRITTEN;
 857                         print_symbol_for_dotconfig(out, sym);
 858                 }
 859
 860 next:
 861                 if (menu->list) {
 862                         menu = menu->list;
 863                         continue;
 864                 }
 865
 866 end_check:
 867                 if (!menu->sym && menu_is_visible(menu) && menu != &rootmenu &&
 868                     menu->prompt->type == P_MENU) {
 869                         fprintf(out, "# end of %s\n", menu_get_prompt(menu));
 870                         need_newline = true;
 871                 }
 872
 873                 if (menu->next) {
 874                         menu = menu->next;
 875                 } else {
 876                         menu = menu->parent;
 877                         if (menu)
 878                                 goto end_check;
 879                 }
 880         }
 881         fclose(out);
 882
 883         for_all_symbols(sym)
 884                 sym->flags &= ~SYMBOL_WRITTEN;
 885
 886         if (*tmpname) {
 887                 if (is_same(name, tmpname)) {
 888                         conf_message("No change to %s", name);
 889                         unlink(tmpname);
 890                         conf_set_changed(false);
 891                         return 0;
 892                 }
 893
 894                 snprintf(oldname, sizeof(oldname), "%s.old", name);
 895                 rename(name, oldname);
 896                 if (rename(tmpname, name))
 897                         return 1;
 898         }
 899
 900         conf_message("configuration written to %s", name);
 901
 902         conf_set_changed(false);
 903
 904         return 0;
 905 }
 906
 907 /* write a dependency file as used by kbuild to track dependencies */
 908 static int conf_write_autoconf_cmd(const char *autoconf_name)
 909 {
 910         char name[PATH_MAX], tmp[PATH_MAX];
 911         FILE *out;
 912         int ret;
 913
 914         ret = snprintf(name, sizeof(name), "%s.cmd", autoconf_name);
 915         if (ret >= sizeof(name)) /* check truncation */
 916                 return -1;
 917
 918         if (make_parent_dir(name))
 919                 return -1;
 920
 921         ret = snprintf(tmp, sizeof(tmp), "%s.cmd.tmp", autoconf_name);
 922         if (ret >= sizeof(tmp)) /* check truncation */
 923                 return -1;
 924
 925         out = fopen(tmp, "w");
 926         if (!out) {
 927                 perror("fopen");
 928                 return -1;
 929         }
 930
 931         fprintf(out, "autoconfig := %s\n", autoconf_name);
 932
 933         fputs(str_get(&autoconf_cmd), out);
 934
 935         fflush(out);
 936         ret = ferror(out); /* error check for all fprintf() calls */
 937         fclose(out);
 938         if (ret)
 939                 return -1;
 940
 941         if (rename(tmp, name)) {
 942                 perror("rename");
 943                 return -1;
 944         }
 945
 946         return 0;
 947 }
 948
 949 static int conf_touch_deps(void)
 950 {
 951         const char *name, *tmp;
 952         struct symbol *sym;
 953         int res;
 954
 955         name = conf_get_autoconfig_name();
 956         tmp = strrchr(name, '/');
 957         depfile_prefix_len = tmp ? tmp - name + 1 : 0;
 958         if (depfile_prefix_len + 1 > sizeof(depfile_path))
 959                 return -1;
 960
 961         strncpy(depfile_path, name, depfile_prefix_len);
 962         depfile_path[depfile_prefix_len] = 0;
 963
 964         conf_read_simple(name, S_DEF_AUTO);
 965         sym_calc_value(modules_sym);
 966
 967         for_all_symbols(sym) {
 968                 sym_calc_value(sym);
 969                 if (sym_is_choice(sym))
 970                         continue;
 971                 if (sym->flags & SYMBOL_WRITE) {
 972                         if (sym->flags & SYMBOL_DEF_AUTO) {
 973                                 /*
 974                                  * symbol has old and new value,
 975                                  * so compare them...
 976                                  */
 977                                 switch (sym->type) {
 978                                 case S_BOOLEAN:
 979                                 case S_TRISTATE:
 980                                         if (sym_get_tristate_value(sym) ==
 981                                             sym->def[S_DEF_AUTO].tri)
 982                                                 continue;
 983                                         break;
 984                                 case S_STRING:
 985                                 case S_HEX:
 986                                 case S_INT:
 987                                         if (!strcmp(sym_get_string_value(sym),
 988                                                     sym->def[S_DEF_AUTO].val))
 989                                                 continue;
 990                                         break;
 991                                 default:
 992                                         break;
 993                                 }
 994                         } else {
 995                                 /*
 996                                  * If there is no old value, only 'no' (unset)
 997                                  * is allowed as new value.
 998                                  */
 999                                 switch (sym->type) {
1000                                 case S_BOOLEAN:
1001                                 case S_TRISTATE:
1002                                         if (sym_get_tristate_value(sym) == no)
1003                                                 continue;
1004                                         break;
1005                                 default:
1006                                         break;
1007                                 }
1008                         }
1009                 } else if (!(sym->flags & SYMBOL_DEF_AUTO))
1010                         /* There is neither an old nor a new value. */
1011                         continue;
1012                 /* else
1013                  *      There is an old value, but no new value ('no' (unset)
1014                  *      isn't saved in auto.conf, so the old value is always
1015                  *      different from 'no').
1016                  */
1017
1018                 res = conf_touch_dep(sym->name);
1019                 if (res)
1020                         return res;
1021         }
1022
1023         return 0;
1024 }
1025
1026 static int __conf_write_autoconf(const char *filename,
1027                                  void (*print_symbol)(FILE *, struct symbol *),
1028                                  const struct comment_style *comment_style)
1029 {
1030         char tmp[PATH_MAX];
1031         FILE *file;
1032         struct symbol *sym;
1033         int ret;
1034
1035         if (make_parent_dir(filename))
1036                 return -1;
1037
1038         ret = snprintf(tmp, sizeof(tmp), "%s.tmp", filename);
1039         if (ret >= sizeof(tmp)) /* check truncation */
1040                 return -1;
1041
1042         file = fopen(tmp, "w");
1043         if (!file) {
1044                 perror("fopen");
1045                 return -1;
1046         }
1047
1048         conf_write_heading(file, comment_style);
1049
1050         for_all_symbols(sym)
1051                 if ((sym->flags & SYMBOL_WRITE) && sym->name)
1052                         print_symbol(file, sym);
1053
1054         fflush(file);
1055         /* check possible errors in conf_write_heading() and print_symbol() */
1056         ret = ferror(file);
1057         fclose(file);
1058         if (ret)
1059                 return -1;
1060
1061         if (rename(tmp, filename)) {
1062                 perror("rename");
1063                 return -1;
1064         }
1065
1066         return 0;
1067 }
1068
1069 int conf_write_autoconf(int overwrite)
1070 {
1071         struct symbol *sym;
1072         const char *autoconf_name = conf_get_autoconfig_name();
1073         int ret;
1074
1075         if (!overwrite && is_present(autoconf_name))
1076                 return 0;
1077
1078         ret = conf_write_autoconf_cmd(autoconf_name);
1079         if (ret)
1080                 return -1;
1081
1082         if (conf_touch_deps())
1083                 return 1;
1084
1085         for_all_symbols(sym)
1086                 sym_calc_value(sym);
1087
1088         ret = __conf_write_autoconf(conf_get_autoheader_name(),
1089                                     print_symbol_for_c,
1090                                     &comment_style_c);
1091         if (ret)
1092                 return ret;
1093
1094         ret = __conf_write_autoconf(conf_get_rustccfg_name(),
1095                                     print_symbol_for_rustccfg,
1096                                     NULL);
1097         if (ret)
1098                 return ret;
1099
1100         /*
1101          * Create include/config/auto.conf. This must be the last step because
1102          * Kbuild has a dependency on auto.conf and this marks the successful
1103          * completion of the previous steps.
1104          */
1105         ret = __conf_write_autoconf(conf_get_autoconfig_name(),
1106                                     print_symbol_for_autoconf,
1107                                     &comment_style_pound);
1108         if (ret)
1109                 return ret;
1110
1111         return 0;
1112 }
1113
1114 static bool conf_changed;
1115 static void (*conf_changed_callback)(bool);
1116
1117 void conf_set_changed(bool val)
1118 {
1119         if (conf_changed_callback && conf_changed != val)
1120                 conf_changed_callback(val);
1121
1122         conf_changed = val;
1123 }
1124
1125 bool conf_get_changed(void)
1126 {
1127         return conf_changed;
1128 }
1129
1130 void conf_set_changed_callback(void (*fn)(bool))
1131 {
1132         conf_changed_callback = fn;
1133 }