scripts/kconfig/confdata.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2002 Roman Zippel <zippel@linux-m68k.org>
   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 <xalloc.h>
  22 #include "internal.h"
  23 #include "lkc.h"
  24
  25 struct gstr autoconf_cmd;
  26
  27 /* return true if 'path' exists, false otherwise */
  28 static bool is_present(const char *path)
  29 {
  30         struct stat st;
  31
  32         return !stat(path, &st);
  33 }
  34
  35 /* return true if 'path' exists and it is a directory, false otherwise */
  36 static bool is_dir(const char *path)
  37 {
  38         struct stat st;
  39
  40         if (stat(path, &st))
  41                 return false;
  42
  43         return S_ISDIR(st.st_mode);
  44 }
  45
  46 /* return true if the given two files are the same, false otherwise */
  47 static bool is_same(const char *file1, const char *file2)
  48 {
  49         int fd1, fd2;
  50         struct stat st1, st2;
  51         void *map1, *map2;
  52         bool ret = false;
  53
  54         fd1 = open(file1, O_RDONLY);
  55         if (fd1 < 0)
  56                 return ret;
  57
  58         fd2 = open(file2, O_RDONLY);
  59         if (fd2 < 0)
  60                 goto close1;
  61
  62         ret = fstat(fd1, &st1);
  63         if (ret)
  64                 goto close2;
  65         ret = fstat(fd2, &st2);
  66         if (ret)
  67                 goto close2;
  68
  69         if (st1.st_size != st2.st_size)
  70                 goto close2;
  71
  72         map1 = mmap(NULL, st1.st_size, PROT_READ, MAP_PRIVATE, fd1, 0);
  73         if (map1 == MAP_FAILED)
  74                 goto close2;
  75
  76         map2 = mmap(NULL, st2.st_size, PROT_READ, MAP_PRIVATE, fd2, 0);
  77         if (map2 == MAP_FAILED)
  78                 goto close2;
  79
  80         if (bcmp(map1, map2, st1.st_size))
  81                 goto close2;
  82
  83         ret = true;
  84 close2:
  85         close(fd2);
  86 close1:
  87         close(fd1);
  88
  89         return ret;
  90 }
  91
  92 /*
  93  * Create the parent directory of the given path.
  94  *
  95  * For example, if 'include/config/auto.conf' is given, create 'include/config'.
  96  */
  97 static int make_parent_dir(const char *path)
  98 {
  99         char tmp[PATH_MAX + 1];
 100         char *p;
 101
 102         strncpy(tmp, path, sizeof(tmp));
 103         tmp[sizeof(tmp) - 1] = 0;
 104
 105         /* Remove the base name. Just return if nothing is left */
 106         p = strrchr(tmp, '/');
 107         if (!p)
 108                 return 0;
 109         *(p + 1) = 0;
 110
 111         /* Just in case it is an absolute path */
 112         p = tmp;
 113         while (*p == '/')
 114                 p++;
 115
 116         while ((p = strchr(p, '/'))) {
 117                 *p = 0;
 118
 119                 /* skip if the directory exists */
 120                 if (!is_dir(tmp) && mkdir(tmp, 0755))
 121                         return -1;
 122
 123                 *p = '/';
 124                 while (*p == '/')
 125                         p++;
 126         }
 127
 128         return 0;
 129 }
 130
 131 static char depfile_path[PATH_MAX];
 132 static size_t depfile_prefix_len;
 133
 134 /* touch depfile for symbol 'name' */
 135 static int conf_touch_dep(const char *name)
 136 {
 137         int fd;
 138
 139         /* check overflow: prefix + name + '\0' must fit in buffer. */
 140         if (depfile_prefix_len + strlen(name) + 1 > sizeof(depfile_path))
 141                 return -1;
 142
 143         strcpy(depfile_path + depfile_prefix_len, name);
 144
 145         fd = open(depfile_path, O_WRONLY | O_CREAT | O_TRUNC, 0644);
 146         if (fd == -1)
 147                 return -1;
 148         close(fd);
 149
 150         return 0;
 151 }
 152
 153 static void conf_warning(const char *fmt, ...)
 154         __attribute__ ((format (printf, 1, 2)));
 155
 156 static void conf_message(const char *fmt, ...)
 157         __attribute__ ((format (printf, 1, 2)));
 158
 159 static const char *conf_filename;
 160 static int conf_lineno, conf_warnings;
 161
 162 bool conf_errors(void)
 163 {
 164         if (conf_warnings)
 165                 return getenv("KCONFIG_WERROR");
 166         return false;
 167 }
 168
 169 static void conf_warning(const char *fmt, ...)
 170 {
 171         va_list ap;
 172         va_start(ap, fmt);
 173         fprintf(stderr, "%s:%d:warning: ", conf_filename, conf_lineno);
 174         vfprintf(stderr, fmt, ap);
 175         fprintf(stderr, "\n");
 176         va_end(ap);
 177         conf_warnings++;
 178 }
 179
 180 static void conf_default_message_callback(const char *s)
 181 {
 182         printf("#\n# ");
 183         printf("%s", s);
 184         printf("\n#\n");
 185 }
 186
 187 static void (*conf_message_callback)(const char *s) =
 188         conf_default_message_callback;
 189 void conf_set_message_callback(void (*fn)(const char *s))
 190 {
 191         conf_message_callback = fn;
 192 }
 193
 194 static void conf_message(const char *fmt, ...)
 195 {
 196         va_list ap;
 197         char buf[4096];
 198
 199         if (!conf_message_callback)
 200                 return;
 201
 202         va_start(ap, fmt);
 203
 204         vsnprintf(buf, sizeof(buf), fmt, ap);
 205         conf_message_callback(buf);
 206         va_end(ap);
 207 }
 208
 209 const char *conf_get_configname(void)
 210 {
 211         char *name = getenv("KCONFIG_CONFIG");
 212
 213         return name ? name : ".config";
 214 }
 215
 216 static const char *conf_get_autoconfig_name(void)
 217 {
 218         char *name = getenv("KCONFIG_AUTOCONFIG");
 219
 220         return name ? name : "include/config/auto.conf";
 221 }
 222
 223 static const char *conf_get_autoheader_name(void)
 224 {
 225         char *name = getenv("KCONFIG_AUTOHEADER");
 226
 227         return name ? name : "include/generated/autoconf.h";
 228 }
 229
 230 static const char *conf_get_rustccfg_name(void)
 231 {
 232         char *name = getenv("KCONFIG_RUSTCCFG");
 233
 234         return name ? name : "include/generated/rustc_cfg";
 235 }
 236
 237 static int conf_set_sym_val(struct symbol *sym, int def, int def_flags, char *p)
 238 {
 239         char *p2;
 240
 241         switch (sym->type) {
 242         case S_TRISTATE:
 243                 if (p[0] == 'm') {
 244                         sym->def[def].tri = mod;
 245                         sym->flags |= def_flags;
 246                         break;
 247                 }
 248                 /* fall through */
 249         case S_BOOLEAN:
 250                 if (p[0] == 'y') {
 251                         sym->def[def].tri = yes;
 252                         sym->flags |= def_flags;
 253                         break;
 254                 }
 255                 if (p[0] == 'n') {
 256                         sym->def[def].tri = no;
 257                         sym->flags |= def_flags;
 258                         break;
 259                 }
 260                 if (def != S_DEF_AUTO)
 261                         conf_warning("symbol value '%s' invalid for %s",
 262                                      p, sym->name);
 263                 return 1;
 264         case S_STRING:
 265                 /* No escaping for S_DEF_AUTO (include/config/auto.conf) */
 266                 if (def != S_DEF_AUTO) {
 267                         if (*p++ != '"')
 268                                 break;
 269                         for (p2 = p; (p2 = strpbrk(p2, "\"\\")); p2++) {
 270                                 if (*p2 == '"') {
 271                                         *p2 = 0;
 272                                         break;
 273                                 }
 274                                 memmove(p2, p2 + 1, strlen(p2));
 275                         }
 276                         if (!p2) {
 277                                 conf_warning("invalid string found");
 278                                 return 1;
 279                         }
 280                 }
 281                 /* fall through */
 282         case S_INT:
 283         case S_HEX:
 284                 if (sym_string_valid(sym, p)) {
 285                         sym->def[def].val = xstrdup(p);
 286                         sym->flags |= def_flags;
 287                 } else {
 288                         if (def != S_DEF_AUTO)
 289                                 conf_warning("symbol value '%s' invalid for %s",
 290                                              p, sym->name);
 291                         return 1;
 292                 }
 293                 break;
 294         default:
 295                 ;
 296         }
 297         return 0;
 298 }
 299
 300 /* like getline(), but the newline character is stripped away */
 301 static ssize_t getline_stripped(char **lineptr, size_t *n, FILE *stream)
 302 {
 303         ssize_t len;
 304
 305         len = getline(lineptr, n, stream);
 306
 307         if (len > 0 && (*lineptr)[len - 1] == '\n') {
 308                 len--;
 309                 (*lineptr)[len] = '\0';
 310
 311                 if (len > 0 && (*lineptr)[len - 1] == '\r') {
 312                         len--;
 313                         (*lineptr)[len] = '\0';
 314                 }
 315         }
 316
 317         return len;
 318 }
 319
 320 int conf_read_simple(const char *name, int def)
 321 {
 322         FILE *in = NULL;
 323         char   *line = NULL;
 324         size_t  line_asize = 0;
 325         char *p, *val;
 326         struct symbol *sym;
 327         int def_flags;
 328         const char *warn_unknown, *sym_name;
 329
 330         warn_unknown = getenv("KCONFIG_WARN_UNKNOWN_SYMBOLS");
 331         if (name) {
 332                 in = zconf_fopen(name);
 333         } else {
 334                 char *env;
 335
 336                 name = conf_get_configname();
 337                 in = zconf_fopen(name);
 338                 if (in)
 339                         goto load;
 340                 conf_set_changed(true);
 341
 342                 env = getenv("KCONFIG_DEFCONFIG_LIST");
 343                 if (!env)
 344                         return 1;
 345
 346                 while (1) {
 347                         bool is_last;
 348
 349                         while (isspace(*env))
 350                                 env++;
 351
 352                         if (!*env)
 353                                 break;
 354
 355                         p = env;
 356                         while (*p && !isspace(*p))
 357                                 p++;
 358
 359                         is_last = (*p == '\0');
 360
 361                         *p = '\0';
 362
 363                         in = zconf_fopen(env);
 364                         if (in) {
 365                                 conf_message("using defaults found in %s",
 366                                              env);
 367                                 goto load;
 368                         }
 369
 370                         if (is_last)
 371                                 break;
 372
 373                         env = p + 1;
 374                 }
 375         }
 376         if (!in)
 377                 return 1;
 378
 379 load:
 380         conf_filename = name;
 381         conf_lineno = 0;
 382         conf_warnings = 0;
 383
 384         def_flags = SYMBOL_DEF << def;
 385         for_all_symbols(sym) {
 386                 sym->flags &= ~(def_flags|SYMBOL_VALID);
 387                 switch (sym->type) {
 388                 case S_INT:
 389                 case S_HEX:
 390                 case S_STRING:
 391                         free(sym->def[def].val);
 392                         /* fall through */
 393                 default:
 394                         sym->def[def].val = NULL;
 395                         sym->def[def].tri = no;
 396                 }
 397         }
 398
 399         expr_invalidate_all();
 400
 401         while (getline_stripped(&line, &line_asize, in) != -1) {
 402                 struct menu *choice;
 403
 404                 conf_lineno++;
 405
 406                 if (!line[0]) /* blank line */
 407                         continue;
 408
 409                 if (line[0] == '#') {
 410                         if (line[1] != ' ')
 411                                 continue;
 412                         p = line + 2;
 413                         if (memcmp(p, CONFIG_, strlen(CONFIG_)))
 414                                 continue;
 415                         sym_name = p + strlen(CONFIG_);
 416                         p = strchr(sym_name, ' ');
 417                         if (!p)
 418                                 continue;
 419                         *p++ = 0;
 420                         if (strcmp(p, "is not set"))
 421                                 continue;
 422
 423                         val = "n";
 424                 } else {
 425                         if (memcmp(line, CONFIG_, strlen(CONFIG_))) {
 426                                 conf_warning("unexpected data: %s", line);
 427                                 continue;
 428                         }
 429
 430                         sym_name = line + strlen(CONFIG_);
 431                         p = strchr(sym_name, '=');
 432                         if (!p) {
 433                                 conf_warning("unexpected data: %s", line);
 434                                 continue;
 435                         }
 436                         *p = 0;
 437                         val = p + 1;
 438                 }
 439
 440                 sym = sym_find(sym_name);
 441                 if (!sym) {
 442                         if (def == S_DEF_AUTO) {
 443                                 /*
 444                                  * Reading from include/config/auto.conf.
 445                                  * If CONFIG_FOO previously existed in auto.conf
 446                                  * but it is missing now, include/config/FOO
 447                                  * must be touched.
 448                                  */
 449                                 conf_touch_dep(sym_name);
 450                         } else {
 451                                 if (warn_unknown)
 452                                         conf_warning("unknown symbol: %s", sym_name);
 453
 454                                 conf_set_changed(true);
 455                         }
 456                         continue;
 457                 }
 458
 459                 if (sym->flags & def_flags)
 460                         conf_warning("override: reassigning to symbol %s", sym->name);
 461
 462                 if (conf_set_sym_val(sym, def, def_flags, val))
 463                         continue;
 464
 465                 /*
 466                  * If this is a choice member, give it the highest priority.
 467                  * If conflicting CONFIG options are given from an input file,
 468                  * the last one wins.
 469                  */
 470                 choice = sym_get_choice_menu(sym);
 471                 if (choice)
 472                         list_move(&sym->choice_link, &choice->choice_members);
 473         }
 474         free(line);
 475         fclose(in);
 476
 477         return 0;
 478 }
 479
 480 int conf_read(const char *name)
 481 {
 482         struct symbol *sym;
 483
 484         conf_set_changed(false);
 485
 486         if (conf_read_simple(name, S_DEF_USER)) {
 487                 sym_calc_value(modules_sym);
 488                 return 1;
 489         }
 490
 491         sym_calc_value(modules_sym);
 492
 493         for_all_symbols(sym) {
 494                 sym_calc_value(sym);
 495                 if (sym_is_choice(sym))
 496                         continue;
 497                 if (sym_has_value(sym) && (sym->flags & SYMBOL_WRITE)) {
 498                         /* check that calculated value agrees with saved value */
 499                         switch (sym->type) {
 500                         case S_BOOLEAN:
 501                         case S_TRISTATE:
 502                                 if (sym->def[S_DEF_USER].tri == sym_get_tristate_value(sym))
 503                                         continue;
 504                                 break;
 505                         default:
 506                                 if (!strcmp(sym->curr.val, sym->def[S_DEF_USER].val))
 507                                         continue;
 508                                 break;
 509                         }
 510                 } else if (!sym_has_value(sym) && !(sym->flags & SYMBOL_WRITE))
 511                         /* no previous value and not saved */
 512                         continue;
 513                 conf_set_changed(true);
 514                 /* maybe print value in verbose mode... */
 515         }
 516
 517         if (conf_warnings)
 518                 conf_set_changed(true);
 519
 520         return 0;
 521 }
 522
 523 struct comment_style {
 524         const char *decoration;
 525         const char *prefix;
 526         const char *postfix;
 527 };
 528
 529 static const struct comment_style comment_style_pound = {
 530         .decoration = "#",
 531         .prefix = "#",
 532         .postfix = "#",
 533 };
 534
 535 static const struct comment_style comment_style_c = {
 536         .decoration = " *",
 537         .prefix = "/*",
 538         .postfix = " */",
 539 };
 540
 541 static void conf_write_heading(FILE *fp, const struct comment_style *cs)
 542 {
 543         if (!cs)
 544                 return;
 545
 546         fprintf(fp, "%s\n", cs->prefix);
 547
 548         fprintf(fp, "%s Automatically generated file; DO NOT EDIT.\n",
 549                 cs->decoration);
 550
 551         fprintf(fp, "%s %s\n", cs->decoration, rootmenu.prompt->text);
 552
 553         fprintf(fp, "%s\n", cs->postfix);
 554 }
 555
 556 /* The returned pointer must be freed on the caller side */
 557 static char *escape_string_value(const char *in)
 558 {
 559         const char *p;
 560         char *out;
 561         size_t len;
 562
 563         len = strlen(in) + strlen("\"\"") + 1;
 564
 565         p = in;
 566         while (1) {
 567                 p += strcspn(p, "\"\\");
 568
 569                 if (p[0] == '\0')
 570                         break;
 571
 572                 len++;
 573                 p++;
 574         }
 575
 576         out = xmalloc(len);
 577         out[0] = '\0';
 578
 579         strcat(out, "\"");
 580
 581         p = in;
 582         while (1) {
 583                 len = strcspn(p, "\"\\");
 584                 strncat(out, p, len);
 585                 p += len;
 586
 587                 if (p[0] == '\0')
 588                         break;
 589
 590                 strcat(out, "\\");
 591                 strncat(out, p++, 1);
 592         }
 593
 594         strcat(out, "\"");
 595
 596         return out;
 597 }
 598
 599 enum output_n { OUTPUT_N, OUTPUT_N_AS_UNSET, OUTPUT_N_NONE };
 600
 601 static void __print_symbol(FILE *fp, struct symbol *sym, enum output_n output_n,
 602                            bool escape_string)
 603 {
 604         const char *val;
 605         char *escaped = NULL;
 606
 607         if (sym->type == S_UNKNOWN)
 608                 return;
 609
 610         val = sym_get_string_value(sym);
 611
 612         if ((sym->type == S_BOOLEAN || sym->type == S_TRISTATE) &&
 613             output_n != OUTPUT_N && *val == 'n') {
 614                 if (output_n == OUTPUT_N_AS_UNSET)
 615                         fprintf(fp, "# %s%s is not set\n", CONFIG_, sym->name);
 616                 return;
 617         }
 618
 619         if (sym->type == S_STRING && escape_string) {
 620                 escaped = escape_string_value(val);
 621                 val = escaped;
 622         }
 623
 624         fprintf(fp, "%s%s=%s\n", CONFIG_, sym->name, val);
 625
 626         free(escaped);
 627 }
 628
 629 static void print_symbol_for_dotconfig(FILE *fp, struct symbol *sym)
 630 {
 631         __print_symbol(fp, sym, OUTPUT_N_AS_UNSET, true);
 632 }
 633
 634 static void print_symbol_for_autoconf(FILE *fp, struct symbol *sym)
 635 {
 636         __print_symbol(fp, sym, OUTPUT_N_NONE, false);
 637 }
 638
 639 void print_symbol_for_listconfig(struct symbol *sym)
 640 {
 641         __print_symbol(stdout, sym, OUTPUT_N, true);
 642 }
 643
 644 static void print_symbol_for_c(FILE *fp, struct symbol *sym)
 645 {
 646         const char *val;
 647         const char *sym_suffix = "";
 648         const char *val_prefix = "";
 649         char *escaped = NULL;
 650
 651         if (sym->type == S_UNKNOWN)
 652                 return;
 653
 654         val = sym_get_string_value(sym);
 655
 656         switch (sym->type) {
 657         case S_BOOLEAN:
 658         case S_TRISTATE:
 659                 switch (*val) {
 660                 case 'n':
 661                         return;
 662                 case 'm':
 663                         sym_suffix = "_MODULE";
 664                         /* fall through */
 665                 default:
 666                         val = "1";
 667                 }
 668                 break;
 669         case S_HEX:
 670                 if (val[0] != '0' || (val[1] != 'x' && val[1] != 'X'))
 671                         val_prefix = "0x";
 672                 break;
 673         case S_STRING:
 674                 escaped = escape_string_value(val);
 675                 val = escaped;
 676         default:
 677                 break;
 678         }
 679
 680         fprintf(fp, "#define %s%s%s %s%s\n", CONFIG_, sym->name, sym_suffix,
 681                 val_prefix, val);
 682
 683         free(escaped);
 684 }
 685
 686 static void print_symbol_for_rustccfg(FILE *fp, struct symbol *sym)
 687 {
 688         const char *val;
 689         const char *val_prefix = "";
 690         char *val_prefixed = NULL;
 691         size_t val_prefixed_len;
 692         char *escaped = NULL;
 693
 694         if (sym->type == S_UNKNOWN)
 695                 return;
 696
 697         val = sym_get_string_value(sym);
 698
 699         switch (sym->type) {
 700         case S_BOOLEAN:
 701         case S_TRISTATE:
 702                 /*
 703                  * We do not care about disabled ones, i.e. no need for
 704                  * what otherwise are "comments" in other printers.
 705                  */
 706                 if (*val == 'n')
 707                         return;
 708
 709                 /*
 710                  * To have similar functionality to the C macro `IS_ENABLED()`
 711                  * we provide an empty `--cfg CONFIG_X` here in both `y`
 712                  * and `m` cases.
 713                  *
 714                  * Then, the common `fprintf()` below will also give us
 715                  * a `--cfg CONFIG_X="y"` or `--cfg CONFIG_X="m"`, which can
 716                  * be used as the equivalent of `IS_BUILTIN()`/`IS_MODULE()`.
 717                  */
 718                 fprintf(fp, "--cfg=%s%s\n", CONFIG_, sym->name);
 719                 break;
 720         case S_HEX:
 721                 if (val[0] != '0' || (val[1] != 'x' && val[1] != 'X'))
 722                         val_prefix = "0x";
 723                 break;
 724         default:
 725                 break;
 726         }
 727
 728         if (strlen(val_prefix) > 0) {
 729                 val_prefixed_len = strlen(val) + strlen(val_prefix) + 1;
 730                 val_prefixed = xmalloc(val_prefixed_len);
 731                 snprintf(val_prefixed, val_prefixed_len, "%s%s", val_prefix, val);
 732                 val = val_prefixed;
 733         }
 734
 735         /* All values get escaped: the `--cfg` option only takes strings */
 736         escaped = escape_string_value(val);
 737         val = escaped;
 738
 739         fprintf(fp, "--cfg=%s%s=%s\n", CONFIG_, sym->name, val);
 740
 741         free(escaped);
 742         free(val_prefixed);
 743 }
 744
 745 /*
 746  * Write out a minimal config.
 747  * All values that has default values are skipped as this is redundant.
 748  */
 749 int conf_write_defconfig(const char *filename)
 750 {
 751         struct symbol *sym;
 752         struct menu *menu;
 753         FILE *out;
 754
 755         out = fopen(filename, "w");
 756         if (!out)
 757                 return 1;
 758
 759         sym_clear_all_valid();
 760
 761         menu_for_each_entry(menu) {
 762                 struct menu *choice;
 763
 764                 sym = menu->sym;
 765
 766                 if (!sym || sym_is_choice(sym))
 767                         continue;
 768
 769                 sym_calc_value(sym);
 770                 if (!(sym->flags & SYMBOL_WRITE))
 771                         continue;
 772                 sym->flags &= ~SYMBOL_WRITE;
 773                 /* Skip unchangeable symbols */
 774                 if (!sym_is_changeable(sym))
 775                         continue;
 776                 /* Skip symbols that are equal to the default */
 777                 if (!strcmp(sym_get_string_value(sym), sym_get_string_default(sym)))
 778                         continue;
 779
 780                 /* Skip choice values that are equal to the default */
 781                 choice = sym_get_choice_menu(sym);
 782                 if (choice) {
 783                         struct symbol *ds;
 784
 785                         ds = sym_choice_default(choice);
 786                         if (sym == ds && sym_get_tristate_value(sym) == yes)
 787                                 continue;
 788                 }
 789                 print_symbol_for_dotconfig(out, sym);
 790         }
 791         fclose(out);
 792         return 0;
 793 }
 794
 795 int conf_write(const char *name)
 796 {
 797         FILE *out;
 798         struct symbol *sym;
 799         struct menu *menu;
 800         const char *str;
 801         char tmpname[PATH_MAX + 1], oldname[PATH_MAX + 1];
 802         char *env;
 803         bool need_newline = false;
 804
 805         if (!name)
 806                 name = conf_get_configname();
 807
 808         if (!*name) {
 809                 fprintf(stderr, "config name is empty\n");
 810                 return -1;
 811         }
 812
 813         if (is_dir(name)) {
 814                 fprintf(stderr, "%s: Is a directory\n", name);
 815                 return -1;
 816         }
 817
 818         if (make_parent_dir(name))
 819                 return -1;
 820
 821         env = getenv("KCONFIG_OVERWRITECONFIG");
 822         if (env && *env) {
 823                 *tmpname = 0;
 824                 out = fopen(name, "w");
 825         } else {
 826                 snprintf(tmpname, sizeof(tmpname), "%s.%d.tmp",
 827                          name, (int)getpid());
 828                 out = fopen(tmpname, "w");
 829         }
 830         if (!out)
 831                 return 1;
 832
 833         conf_write_heading(out, &comment_style_pound);
 834
 835         if (!conf_get_changed())
 836                 sym_clear_all_valid();
 837
 838         menu = rootmenu.list;
 839         while (menu) {
 840                 sym = menu->sym;
 841                 if (!sym) {
 842                         if (!menu_is_visible(menu))
 843                                 goto next;
 844                         str = menu_get_prompt(menu);
 845                         fprintf(out, "\n"
 846                                      "#\n"
 847                                      "# %s\n"
 848                                      "#\n", str);
 849                         need_newline = false;
 850                 } else if (!sym_is_choice(sym) &&
 851                            !(sym->flags & SYMBOL_WRITTEN)) {
 852                         sym_calc_value(sym);
 853                         if (!(sym->flags & SYMBOL_WRITE))
 854                                 goto next;
 855                         if (need_newline) {
 856                                 fprintf(out, "\n");
 857                                 need_newline = false;
 858                         }
 859                         sym->flags |= SYMBOL_WRITTEN;
 860                         print_symbol_for_dotconfig(out, sym);
 861                 }
 862
 863 next:
 864                 if (menu->list) {
 865                         menu = menu->list;
 866                         continue;
 867                 }
 868
 869 end_check:
 870                 if (!menu->sym && menu_is_visible(menu) && menu != &rootmenu &&
 871                     menu->prompt->type == P_MENU) {
 872                         fprintf(out, "# end of %s\n", menu_get_prompt(menu));
 873                         need_newline = true;
 874                 }
 875
 876                 if (menu->next) {
 877                         menu = menu->next;
 878                 } else {
 879                         menu = menu->parent;
 880                         if (menu)
 881                                 goto end_check;
 882                 }
 883         }
 884         fclose(out);
 885
 886         for_all_symbols(sym)
 887                 sym->flags &= ~SYMBOL_WRITTEN;
 888
 889         if (*tmpname) {
 890                 if (is_same(name, tmpname)) {
 891                         conf_message("No change to %s", name);
 892                         unlink(tmpname);
 893                         conf_set_changed(false);
 894                         return 0;
 895                 }
 896
 897                 snprintf(oldname, sizeof(oldname), "%s.old", name);
 898                 rename(name, oldname);
 899                 if (rename(tmpname, name))
 900                         return 1;
 901         }
 902
 903         conf_message("configuration written to %s", name);
 904
 905         conf_set_changed(false);
 906
 907         return 0;
 908 }
 909
 910 /* write a dependency file as used by kbuild to track dependencies */
 911 static int conf_write_autoconf_cmd(const char *autoconf_name)
 912 {
 913         char name[PATH_MAX], tmp[PATH_MAX];
 914         FILE *out;
 915         int ret;
 916
 917         ret = snprintf(name, sizeof(name), "%s.cmd", autoconf_name);
 918         if (ret >= sizeof(name)) /* check truncation */
 919                 return -1;
 920
 921         if (make_parent_dir(name))
 922                 return -1;
 923
 924         ret = snprintf(tmp, sizeof(tmp), "%s.cmd.tmp", autoconf_name);
 925         if (ret >= sizeof(tmp)) /* check truncation */
 926                 return -1;
 927
 928         out = fopen(tmp, "w");
 929         if (!out) {
 930                 perror("fopen");
 931                 return -1;
 932         }
 933
 934         fprintf(out, "autoconfig := %s\n", autoconf_name);
 935
 936         fputs(str_get(&autoconf_cmd), out);
 937
 938         fflush(out);
 939         ret = ferror(out); /* error check for all fprintf() calls */
 940         fclose(out);
 941         if (ret)
 942                 return -1;
 943
 944         if (rename(tmp, name)) {
 945                 perror("rename");
 946                 return -1;
 947         }
 948
 949         return 0;
 950 }
 951
 952 static int conf_touch_deps(void)
 953 {
 954         const char *name, *tmp;
 955         struct symbol *sym;
 956         int res;
 957
 958         name = conf_get_autoconfig_name();
 959         tmp = strrchr(name, '/');
 960         depfile_prefix_len = tmp ? tmp - name + 1 : 0;
 961         if (depfile_prefix_len + 1 > sizeof(depfile_path))
 962                 return -1;
 963
 964         strncpy(depfile_path, name, depfile_prefix_len);
 965         depfile_path[depfile_prefix_len] = 0;
 966
 967         conf_read_simple(name, S_DEF_AUTO);
 968         sym_calc_value(modules_sym);
 969
 970         for_all_symbols(sym) {
 971                 sym_calc_value(sym);
 972                 if (sym_is_choice(sym))
 973                         continue;
 974                 if (sym->flags & SYMBOL_WRITE) {
 975                         if (sym->flags & SYMBOL_DEF_AUTO) {
 976                                 /*
 977                                  * symbol has old and new value,
 978                                  * so compare them...
 979                                  */
 980                                 switch (sym->type) {
 981                                 case S_BOOLEAN:
 982                                 case S_TRISTATE:
 983                                         if (sym_get_tristate_value(sym) ==
 984                                             sym->def[S_DEF_AUTO].tri)
 985                                                 continue;
 986                                         break;
 987                                 case S_STRING:
 988                                 case S_HEX:
 989                                 case S_INT:
 990                                         if (!strcmp(sym_get_string_value(sym),
 991                                                     sym->def[S_DEF_AUTO].val))
 992                                                 continue;
 993                                         break;
 994                                 default:
 995                                         break;
 996                                 }
 997                         } else {
 998                                 /*
 999                                  * If there is no old value, only 'no' (unset)
1000                                  * is allowed as new value.
1001                                  */
1002                                 switch (sym->type) {
1003                                 case S_BOOLEAN:
1004                                 case S_TRISTATE:
1005                                         if (sym_get_tristate_value(sym) == no)
1006                                                 continue;
1007                                         break;
1008                                 default:
1009                                         break;
1010                                 }
1011                         }
1012                 } else if (!(sym->flags & SYMBOL_DEF_AUTO))
1013                         /* There is neither an old nor a new value. */
1014                         continue;
1015                 /* else
1016                  *      There is an old value, but no new value ('no' (unset)
1017                  *      isn't saved in auto.conf, so the old value is always
1018                  *      different from 'no').
1019                  */
1020
1021                 res = conf_touch_dep(sym->name);
1022                 if (res)
1023                         return res;
1024         }
1025
1026         return 0;
1027 }
1028
1029 static int __conf_write_autoconf(const char *filename,
1030                                  void (*print_symbol)(FILE *, struct symbol *),
1031                                  const struct comment_style *comment_style)
1032 {
1033         char tmp[PATH_MAX];
1034         FILE *file;
1035         struct symbol *sym;
1036         int ret;
1037
1038         if (make_parent_dir(filename))
1039                 return -1;
1040
1041         ret = snprintf(tmp, sizeof(tmp), "%s.tmp", filename);
1042         if (ret >= sizeof(tmp)) /* check truncation */
1043                 return -1;
1044
1045         file = fopen(tmp, "w");
1046         if (!file) {
1047                 perror("fopen");
1048                 return -1;
1049         }
1050
1051         conf_write_heading(file, comment_style);
1052
1053         for_all_symbols(sym)
1054                 if ((sym->flags & SYMBOL_WRITE) && sym->name)
1055                         print_symbol(file, sym);
1056
1057         fflush(file);
1058         /* check possible errors in conf_write_heading() and print_symbol() */
1059         ret = ferror(file);
1060         fclose(file);
1061         if (ret)
1062                 return -1;
1063
1064         if (rename(tmp, filename)) {
1065                 perror("rename");
1066                 return -1;
1067         }
1068
1069         return 0;
1070 }
1071
1072 int conf_write_autoconf(int overwrite)
1073 {
1074         struct symbol *sym;
1075         const char *autoconf_name = conf_get_autoconfig_name();
1076         int ret;
1077
1078         if (!overwrite && is_present(autoconf_name))
1079                 return 0;
1080
1081         ret = conf_write_autoconf_cmd(autoconf_name);
1082         if (ret)
1083                 return -1;
1084
1085         if (conf_touch_deps())
1086                 return 1;
1087
1088         for_all_symbols(sym)
1089                 sym_calc_value(sym);
1090
1091         ret = __conf_write_autoconf(conf_get_autoheader_name(),
1092                                     print_symbol_for_c,
1093                                     &comment_style_c);
1094         if (ret)
1095                 return ret;
1096
1097         ret = __conf_write_autoconf(conf_get_rustccfg_name(),
1098                                     print_symbol_for_rustccfg,
1099                                     NULL);
1100         if (ret)
1101                 return ret;
1102
1103         /*
1104          * Create include/config/auto.conf. This must be the last step because
1105          * Kbuild has a dependency on auto.conf and this marks the successful
1106          * completion of the previous steps.
1107          */
1108         ret = __conf_write_autoconf(conf_get_autoconfig_name(),
1109                                     print_symbol_for_autoconf,
1110                                     &comment_style_pound);
1111         if (ret)
1112                 return ret;
1113
1114         return 0;
1115 }
1116
1117 static bool conf_changed;
1118 static void (*conf_changed_callback)(bool);
1119
1120 void conf_set_changed(bool val)
1121 {
1122         if (conf_changed_callback && conf_changed != val)
1123                 conf_changed_callback(val);
1124
1125         conf_changed = val;
1126 }
1127
1128 bool conf_get_changed(void)
1129 {
1130         return conf_changed;
1131 }
1132
1133 void conf_set_changed_callback(void (*fn)(bool))
1134 {
1135         conf_changed_callback = fn;
1136 }