tools/perf/util/config.c

   1 /*
   2  * GIT - The information manager from hell
   3  *
   4  * Copyright (C) Linus Torvalds, 2005
   5  * Copyright (C) Johannes Schindelin, 2005
   6  *
   7  */
   8 #include "util.h"
   9 #include "cache.h"
  10 #include "exec_cmd.h"
  11
  12 #define MAXNAME (256)
  13
  14 static FILE *config_file;
  15 static const char *config_file_name;
  16 static int config_linenr;
  17 static int config_file_eof;
  18
  19 const char *config_exclusive_filename = NULL;
  20
  21 static int get_next_char(void)
  22 {
  23         int c;
  24         FILE *f;
  25
  26         c = '\n';
  27         if ((f = config_file) != NULL) {
  28                 c = fgetc(f);
  29                 if (c == '\r') {
  30                         /* DOS like systems */
  31                         c = fgetc(f);
  32                         if (c != '\n') {
  33                                 ungetc(c, f);
  34                                 c = '\r';
  35                         }
  36                 }
  37                 if (c == '\n')
  38                         config_linenr++;
  39                 if (c == EOF) {
  40                         config_file_eof = 1;
  41                         c = '\n';
  42                 }
  43         }
  44         return c;
  45 }
  46
  47 static char *parse_value(void)
  48 {
  49         static char value[1024];
  50         int quote = 0, comment = 0, space = 0;
  51         size_t len = 0;
  52
  53         for (;;) {
  54                 int c = get_next_char();
  55
  56                 if (len >= sizeof(value) - 1)
  57                         return NULL;
  58                 if (c == '\n') {
  59                         if (quote)
  60                                 return NULL;
  61                         value[len] = 0;
  62                         return value;
  63                 }
  64                 if (comment)
  65                         continue;
  66                 if (isspace(c) && !quote) {
  67                         space = 1;
  68                         continue;
  69                 }
  70                 if (!quote) {
  71                         if (c == ';' || c == '#') {
  72                                 comment = 1;
  73                                 continue;
  74                         }
  75                 }
  76                 if (space) {
  77                         if (len)
  78                                 value[len++] = ' ';
  79                         space = 0;
  80                 }
  81                 if (c == '\\') {
  82                         c = get_next_char();
  83                         switch (c) {
  84                         case '\n':
  85                                 continue;
  86                         case 't':
  87                                 c = '\t';
  88                                 break;
  89                         case 'b':
  90                                 c = '\b';
  91                                 break;
  92                         case 'n':
  93                                 c = '\n';
  94                                 break;
  95                         /* Some characters escape as themselves */
  96                         case '\\': case '"':
  97                                 break;
  98                         /* Reject unknown escape sequences */
  99                         default:
 100                                 return NULL;
 101                         }
 102                         value[len++] = c;
 103                         continue;
 104                 }
 105                 if (c == '"') {
 106                         quote = 1-quote;
 107                         continue;
 108                 }
 109                 value[len++] = c;
 110         }
 111 }
 112
 113 static inline int iskeychar(int c)
 114 {
 115         return isalnum(c) || c == '-';
 116 }
 117
 118 static int get_value(config_fn_t fn, void *data, char *name, unsigned int len)
 119 {
 120         int c;
 121         char *value;
 122
 123         /* Get the full name */
 124         for (;;) {
 125                 c = get_next_char();
 126                 if (config_file_eof)
 127                         break;
 128                 if (!iskeychar(c))
 129                         break;
 130                 name[len++] = tolower(c);
 131                 if (len >= MAXNAME)
 132                         return -1;
 133         }
 134         name[len] = 0;
 135         while (c == ' ' || c == '\t')
 136                 c = get_next_char();
 137
 138         value = NULL;
 139         if (c != '\n') {
 140                 if (c != '=')
 141                         return -1;
 142                 value = parse_value();
 143                 if (!value)
 144                         return -1;
 145         }
 146         return fn(name, value, data);
 147 }
 148
 149 static int get_extended_base_var(char *name, int baselen, int c)
 150 {
 151         do {
 152                 if (c == '\n')
 153                         return -1;
 154                 c = get_next_char();
 155         } while (isspace(c));
 156
 157         /* We require the format to be '[base "extension"]' */
 158         if (c != '"')
 159                 return -1;
 160         name[baselen++] = '.';
 161
 162         for (;;) {
 163                 int ch = get_next_char();
 164
 165                 if (ch == '\n')
 166                         return -1;
 167                 if (ch == '"')
 168                         break;
 169                 if (ch == '\\') {
 170                         ch = get_next_char();
 171                         if (ch == '\n')
 172                                 return -1;
 173                 }
 174                 name[baselen++] = ch;
 175                 if (baselen > MAXNAME / 2)
 176                         return -1;
 177         }
 178
 179         /* Final ']' */
 180         if (get_next_char() != ']')
 181                 return -1;
 182         return baselen;
 183 }
 184
 185 static int get_base_var(char *name)
 186 {
 187         int baselen = 0;
 188
 189         for (;;) {
 190                 int c = get_next_char();
 191                 if (config_file_eof)
 192                         return -1;
 193                 if (c == ']')
 194                         return baselen;
 195                 if (isspace(c))
 196                         return get_extended_base_var(name, baselen, c);
 197                 if (!iskeychar(c) && c != '.')
 198                         return -1;
 199                 if (baselen > MAXNAME / 2)
 200                         return -1;
 201                 name[baselen++] = tolower(c);
 202         }
 203 }
 204
 205 static int perf_parse_file(config_fn_t fn, void *data)
 206 {
 207         int comment = 0;
 208         int baselen = 0;
 209         static char var[MAXNAME];
 210
 211         /* U+FEFF Byte Order Mark in UTF8 */
 212         static const unsigned char *utf8_bom = (unsigned char *) "\xef\xbb\xbf";
 213         const unsigned char *bomptr = utf8_bom;
 214
 215         for (;;) {
 216                 int c = get_next_char();
 217                 if (bomptr && *bomptr) {
 218                         /* We are at the file beginning; skip UTF8-encoded BOM
 219                          * if present. Sane editors won't put this in on their
 220                          * own, but e.g. Windows Notepad will do it happily. */
 221                         if ((unsigned char) c == *bomptr) {
 222                                 bomptr++;
 223                                 continue;
 224                         } else {
 225                                 /* Do not tolerate partial BOM. */
 226                                 if (bomptr != utf8_bom)
 227                                         break;
 228                                 /* No BOM at file beginning. Cool. */
 229                                 bomptr = NULL;
 230                         }
 231                 }
 232                 if (c == '\n') {
 233                         if (config_file_eof)
 234                                 return 0;
 235                         comment = 0;
 236                         continue;
 237                 }
 238                 if (comment || isspace(c))
 239                         continue;
 240                 if (c == '#' || c == ';') {
 241                         comment = 1;
 242                         continue;
 243                 }
 244                 if (c == '[') {
 245                         baselen = get_base_var(var);
 246                         if (baselen <= 0)
 247                                 break;
 248                         var[baselen++] = '.';
 249                         var[baselen] = 0;
 250                         continue;
 251                 }
 252                 if (!isalpha(c))
 253                         break;
 254                 var[baselen] = tolower(c);
 255                 if (get_value(fn, data, var, baselen+1) < 0)
 256                         break;
 257         }
 258         die("bad config file line %d in %s", config_linenr, config_file_name);
 259 }
 260
 261 static int parse_unit_factor(const char *end, unsigned long *val)
 262 {
 263         if (!*end)
 264                 return 1;
 265         else if (!strcasecmp(end, "k")) {
 266                 *val *= 1024;
 267                 return 1;
 268         }
 269         else if (!strcasecmp(end, "m")) {
 270                 *val *= 1024 * 1024;
 271                 return 1;
 272         }
 273         else if (!strcasecmp(end, "g")) {
 274                 *val *= 1024 * 1024 * 1024;
 275                 return 1;
 276         }
 277         return 0;
 278 }
 279
 280 static int perf_parse_long(const char *value, long *ret)
 281 {
 282         if (value && *value) {
 283                 char *end;
 284                 long val = strtol(value, &end, 0);
 285                 unsigned long factor = 1;
 286                 if (!parse_unit_factor(end, &factor))
 287                         return 0;
 288                 *ret = val * factor;
 289                 return 1;
 290         }
 291         return 0;
 292 }
 293
 294 int perf_parse_ulong(const char *value, unsigned long *ret)
 295 {
 296         if (value && *value) {
 297                 char *end;
 298                 unsigned long val = strtoul(value, &end, 0);
 299                 if (!parse_unit_factor(end, &val))
 300                         return 0;
 301                 *ret = val;
 302                 return 1;
 303         }
 304         return 0;
 305 }
 306
 307 static void die_bad_config(const char *name)
 308 {
 309         if (config_file_name)
 310                 die("bad config value for '%s' in %s", name, config_file_name);
 311         die("bad config value for '%s'", name);
 312 }
 313
 314 int perf_config_int(const char *name, const char *value)
 315 {
 316         long ret = 0;
 317         if (!perf_parse_long(value, &ret))
 318                 die_bad_config(name);
 319         return ret;
 320 }
 321
 322 unsigned long perf_config_ulong(const char *name, const char *value)
 323 {
 324         unsigned long ret;
 325         if (!perf_parse_ulong(value, &ret))
 326                 die_bad_config(name);
 327         return ret;
 328 }
 329
 330 int perf_config_bool_or_int(const char *name, const char *value, int *is_bool)
 331 {
 332         *is_bool = 1;
 333         if (!value)
 334                 return 1;
 335         if (!*value)
 336                 return 0;
 337         if (!strcasecmp(value, "true") || !strcasecmp(value, "yes") || !strcasecmp(value, "on"))
 338                 return 1;
 339         if (!strcasecmp(value, "false") || !strcasecmp(value, "no") || !strcasecmp(value, "off"))
 340                 return 0;
 341         *is_bool = 0;
 342         return perf_config_int(name, value);
 343 }
 344
 345 int perf_config_bool(const char *name, const char *value)
 346 {
 347         int discard;
 348         return !!perf_config_bool_or_int(name, value, &discard);
 349 }
 350
 351 int perf_config_string(const char **dest, const char *var, const char *value)
 352 {
 353         if (!value)
 354                 return config_error_nonbool(var);
 355         *dest = strdup(value);
 356         return 0;
 357 }
 358
 359 static int perf_default_core_config(const char *var __used, const char *value __used)
 360 {
 361         /* Add other config variables here and to Documentation/config.txt. */
 362         return 0;
 363 }
 364
 365 int perf_default_config(const char *var, const char *value, void *dummy __used)
 366 {
 367         if (!prefixcmp(var, "core."))
 368                 return perf_default_core_config(var, value);
 369
 370         /* Add other config variables here and to Documentation/config.txt. */
 371         return 0;
 372 }
 373
 374 int perf_config_from_file(config_fn_t fn, const char *filename, void *data)
 375 {
 376         int ret;
 377         FILE *f = fopen(filename, "r");
 378
 379         ret = -1;
 380         if (f) {
 381                 config_file = f;
 382                 config_file_name = filename;
 383                 config_linenr = 1;
 384                 config_file_eof = 0;
 385                 ret = perf_parse_file(fn, data);
 386                 fclose(f);
 387                 config_file_name = NULL;
 388         }
 389         return ret;
 390 }
 391
 392 const char *perf_etc_perfconfig(void)
 393 {
 394         static const char *system_wide;
 395         if (!system_wide)
 396                 system_wide = system_path(ETC_PERFCONFIG);
 397         return system_wide;
 398 }
 399
 400 static int perf_env_bool(const char *k, int def)
 401 {
 402         const char *v = getenv(k);
 403         return v ? perf_config_bool(k, v) : def;
 404 }
 405
 406 int perf_config_system(void)
 407 {
 408         return !perf_env_bool("PERF_CONFIG_NOSYSTEM", 0);
 409 }
 410
 411 int perf_config_global(void)
 412 {
 413         return !perf_env_bool("PERF_CONFIG_NOGLOBAL", 0);
 414 }
 415
 416 int perf_config(config_fn_t fn, void *data)
 417 {
 418         int ret = 0, found = 0;
 419         const char *home = NULL;
 420
 421         /* Setting $PERF_CONFIG makes perf read _only_ the given config file. */
 422         if (config_exclusive_filename)
 423                 return perf_config_from_file(fn, config_exclusive_filename, data);
 424         if (perf_config_system() && !access(perf_etc_perfconfig(), R_OK)) {
 425                 ret += perf_config_from_file(fn, perf_etc_perfconfig(),
 426                                             data);
 427                 found += 1;
 428         }
 429
 430         home = getenv("HOME");
 431         if (perf_config_global() && home) {
 432                 char *user_config = strdup(mkpath("%s/.perfconfig", home));
 433                 if (!access(user_config, R_OK)) {
 434                         ret += perf_config_from_file(fn, user_config, data);
 435                         found += 1;
 436                 }
 437                 free(user_config);
 438         }
 439
 440         if (found == 0)
 441                 return -1;
 442         return ret;
 443 }
 444
 445 /*
 446  * Find all the stuff for perf_config_set() below.
 447  */
 448
 449 #define MAX_MATCHES 512
 450
 451 static struct {
 452         int baselen;
 453         char* key;
 454         int do_not_match;
 455         regex_t* value_regex;
 456         int multi_replace;
 457         size_t offset[MAX_MATCHES];
 458         enum { START, SECTION_SEEN, SECTION_END_SEEN, KEY_SEEN } state;
 459         int seen;
 460 } store;
 461
 462 static int matches(const char* key, const char* value)
 463 {
 464         return !strcmp(key, store.key) &&
 465                 (store.value_regex == NULL ||
 466                  (store.do_not_match ^
 467                   !regexec(store.value_regex, value, 0, NULL, 0)));
 468 }
 469
 470 static int store_aux(const char* key, const char* value, void *cb __used)
 471 {
 472         int section_len;
 473         const char *ep;
 474
 475         switch (store.state) {
 476         case KEY_SEEN:
 477                 if (matches(key, value)) {
 478                         if (store.seen == 1 && store.multi_replace == 0) {
 479                                 warning("%s has multiple values", key);
 480                         } else if (store.seen >= MAX_MATCHES) {
 481                                 error("too many matches for %s", key);
 482                                 return 1;
 483                         }
 484
 485                         store.offset[store.seen] = ftell(config_file);
 486                         store.seen++;
 487                 }
 488                 break;
 489         case SECTION_SEEN:
 490                 /*
 491                  * What we are looking for is in store.key (both
 492                  * section and var), and its section part is baselen
 493                  * long.  We found key (again, both section and var).
 494                  * We would want to know if this key is in the same
 495                  * section as what we are looking for.  We already
 496                  * know we are in the same section as what should
 497                  * hold store.key.
 498                  */
 499                 ep = strrchr(key, '.');
 500                 section_len = ep - key;
 501
 502                 if ((section_len != store.baselen) ||
 503                     memcmp(key, store.key, section_len+1)) {
 504                         store.state = SECTION_END_SEEN;
 505                         break;
 506                 }
 507
 508                 /*
 509                  * Do not increment matches: this is no match, but we
 510                  * just made sure we are in the desired section.
 511                  */
 512                 store.offset[store.seen] = ftell(config_file);
 513                 /* fallthru */
 514         case SECTION_END_SEEN:
 515         case START:
 516                 if (matches(key, value)) {
 517                         store.offset[store.seen] = ftell(config_file);
 518                         store.state = KEY_SEEN;
 519                         store.seen++;
 520                 } else {
 521                         if (strrchr(key, '.') - key == store.baselen &&
 522                               !strncmp(key, store.key, store.baselen)) {
 523                                         store.state = SECTION_SEEN;
 524                                         store.offset[store.seen] = ftell(config_file);
 525                         }
 526                 }
 527         default:
 528                 break;
 529         }
 530         return 0;
 531 }
 532
 533 static int store_write_section(int fd, const char* key)
 534 {
 535         const char *dot;
 536         int i, success;
 537         struct strbuf sb = STRBUF_INIT;
 538
 539         dot = memchr(key, '.', store.baselen);
 540         if (dot) {
 541                 strbuf_addf(&sb, "[%.*s \"", (int)(dot - key), key);
 542                 for (i = dot - key + 1; i < store.baselen; i++) {
 543                         if (key[i] == '"' || key[i] == '\\')
 544                                 strbuf_addch(&sb, '\\');
 545                         strbuf_addch(&sb, key[i]);
 546                 }
 547                 strbuf_addstr(&sb, "\"]\n");
 548         } else {
 549                 strbuf_addf(&sb, "[%.*s]\n", store.baselen, key);
 550         }
 551
 552         success = (write_in_full(fd, sb.buf, sb.len) == (ssize_t)sb.len);
 553         strbuf_release(&sb);
 554
 555         return success;
 556 }
 557
 558 static int store_write_pair(int fd, const char* key, const char* value)
 559 {
 560         int i, success;
 561         int length = strlen(key + store.baselen + 1);
 562         const char *quote = "";
 563         struct strbuf sb = STRBUF_INIT;
 564
 565         /*
 566          * Check to see if the value needs to be surrounded with a dq pair.
 567          * Note that problematic characters are always backslash-quoted; this
 568          * check is about not losing leading or trailing SP and strings that
 569          * follow beginning-of-comment characters (i.e. ';' and '#') by the
 570          * configuration parser.
 571          */
 572         if (value[0] == ' ')
 573                 quote = "\"";
 574         for (i = 0; value[i]; i++)
 575                 if (value[i] == ';' || value[i] == '#')
 576                         quote = "\"";
 577         if (i && value[i - 1] == ' ')
 578                 quote = "\"";
 579
 580         strbuf_addf(&sb, "\t%.*s = %s",
 581                     length, key + store.baselen + 1, quote);
 582
 583         for (i = 0; value[i]; i++)
 584                 switch (value[i]) {
 585                 case '\n':
 586                         strbuf_addstr(&sb, "\\n");
 587                         break;
 588                 case '\t':
 589                         strbuf_addstr(&sb, "\\t");
 590                         break;
 591                 case '"':
 592                 case '\\':
 593                         strbuf_addch(&sb, '\\');
 594                 default:
 595                         strbuf_addch(&sb, value[i]);
 596                         break;
 597                 }
 598         strbuf_addf(&sb, "%s\n", quote);
 599
 600         success = (write_in_full(fd, sb.buf, sb.len) == (ssize_t)sb.len);
 601         strbuf_release(&sb);
 602
 603         return success;
 604 }
 605
 606 static ssize_t find_beginning_of_line(const char* contents, size_t size,
 607         size_t offset_, int* found_bracket)
 608 {
 609         size_t equal_offset = size, bracket_offset = size;
 610         ssize_t offset;
 611
 612 contline:
 613         for (offset = offset_-2; offset > 0
 614                         && contents[offset] != '\n'; offset--)
 615                 switch (contents[offset]) {
 616                         case '=': equal_offset = offset; break;
 617                         case ']': bracket_offset = offset; break;
 618                         default: break;
 619                 }
 620         if (offset > 0 && contents[offset-1] == '\\') {
 621                 offset_ = offset;
 622                 goto contline;
 623         }
 624         if (bracket_offset < equal_offset) {
 625                 *found_bracket = 1;
 626                 offset = bracket_offset+1;
 627         } else
 628                 offset++;
 629
 630         return offset;
 631 }
 632
 633 int perf_config_set(const char* key, const char* value)
 634 {
 635         return perf_config_set_multivar(key, value, NULL, 0);
 636 }
 637
 638 /*
 639  * If value==NULL, unset in (remove from) config,
 640  * if value_regex!=NULL, disregard key/value pairs where value does not match.
 641  * if multi_replace==0, nothing, or only one matching key/value is replaced,
 642  *     else all matching key/values (regardless how many) are removed,
 643  *     before the new pair is written.
 644  *
 645  * Returns 0 on success.
 646  *
 647  * This function does this:
 648  *
 649  * - it locks the config file by creating ".perf/config.lock"
 650  *
 651  * - it then parses the config using store_aux() as validator to find
 652  *   the position on the key/value pair to replace. If it is to be unset,
 653  *   it must be found exactly once.
 654  *
 655  * - the config file is mmap()ed and the part before the match (if any) is
 656  *   written to the lock file, then the changed part and the rest.
 657  *
 658  * - the config file is removed and the lock file rename()d to it.
 659  *
 660  */
 661 int perf_config_set_multivar(const char* key, const char* value,
 662         const char* value_regex, int multi_replace)
 663 {
 664         int i, dot;
 665         int fd = -1, in_fd;
 666         int ret = 0;
 667         char* config_filename;
 668         const char* last_dot = strrchr(key, '.');
 669
 670         if (config_exclusive_filename)
 671                 config_filename = strdup(config_exclusive_filename);
 672         else
 673                 config_filename = perf_pathdup("config");
 674
 675         /*
 676          * Since "key" actually contains the section name and the real
 677          * key name separated by a dot, we have to know where the dot is.
 678          */
 679
 680         if (last_dot == NULL) {
 681                 error("key does not contain a section: %s", key);
 682                 ret = 2;
 683                 goto out_free;
 684         }
 685         store.baselen = last_dot - key;
 686
 687         store.multi_replace = multi_replace;
 688
 689         /*
 690          * Validate the key and while at it, lower case it for matching.
 691          */
 692         store.key = malloc(strlen(key) + 1);
 693         dot = 0;
 694         for (i = 0; key[i]; i++) {
 695                 unsigned char c = key[i];
 696                 if (c == '.')
 697                         dot = 1;
 698                 /* Leave the extended basename untouched.. */
 699                 if (!dot || i > store.baselen) {
 700                         if (!iskeychar(c) || (i == store.baselen+1 && !isalpha(c))) {
 701                                 error("invalid key: %s", key);
 702                                 free(store.key);
 703                                 ret = 1;
 704                                 goto out_free;
 705                         }
 706                         c = tolower(c);
 707                 } else if (c == '\n') {
 708                         error("invalid key (newline): %s", key);
 709                         free(store.key);
 710                         ret = 1;
 711                         goto out_free;
 712                 }
 713                 store.key[i] = c;
 714         }
 715         store.key[i] = 0;
 716
 717         /*
 718          * If .perf/config does not exist yet, write a minimal version.
 719          */
 720         in_fd = open(config_filename, O_RDONLY);
 721         if ( in_fd < 0 ) {
 722                 free(store.key);
 723
 724                 if ( ENOENT != errno ) {
 725                         error("opening %s: %s", config_filename,
 726                               strerror(errno));
 727                         ret = 3; /* same as "invalid config file" */
 728                         goto out_free;
 729                 }
 730                 /* if nothing to unset, error out */
 731                 if (value == NULL) {
 732                         ret = 5;
 733                         goto out_free;
 734                 }
 735
 736                 store.key = (char*)key;
 737                 if (!store_write_section(fd, key) ||
 738                     !store_write_pair(fd, key, value))
 739                         goto write_err_out;
 740         } else {
 741                 struct stat st;
 742                 char *contents;
 743                 ssize_t contents_sz, copy_begin, copy_end;
 744                 int new_line = 0;
 745
 746                 if (value_regex == NULL)
 747                         store.value_regex = NULL;
 748                 else {
 749                         if (value_regex[0] == '!') {
 750                                 store.do_not_match = 1;
 751                                 value_regex++;
 752                         } else
 753                                 store.do_not_match = 0;
 754
 755                         store.value_regex = (regex_t*)malloc(sizeof(regex_t));
 756                         if (regcomp(store.value_regex, value_regex,
 757                                         REG_EXTENDED)) {
 758                                 error("invalid pattern: %s", value_regex);
 759                                 free(store.value_regex);
 760                                 ret = 6;
 761                                 goto out_free;
 762                         }
 763                 }
 764
 765                 store.offset[0] = 0;
 766                 store.state = START;
 767                 store.seen = 0;
 768
 769                 /*
 770                  * After this, store.offset will contain the *end* offset
 771                  * of the last match, or remain at 0 if no match was found.
 772                  * As a side effect, we make sure to transform only a valid
 773                  * existing config file.
 774                  */
 775                 if (perf_config_from_file(store_aux, config_filename, NULL)) {
 776                         error("invalid config file %s", config_filename);
 777                         free(store.key);
 778                         if (store.value_regex != NULL) {
 779                                 regfree(store.value_regex);
 780                                 free(store.value_regex);
 781                         }
 782                         ret = 3;
 783                         goto out_free;
 784                 }
 785
 786                 free(store.key);
 787                 if (store.value_regex != NULL) {
 788                         regfree(store.value_regex);
 789                         free(store.value_regex);
 790                 }
 791
 792                 /* if nothing to unset, or too many matches, error out */
 793                 if ((store.seen == 0 && value == NULL) ||
 794                                 (store.seen > 1 && multi_replace == 0)) {
 795                         ret = 5;
 796                         goto out_free;
 797                 }
 798
 799                 fstat(in_fd, &st);
 800                 contents_sz = xsize_t(st.st_size);
 801                 contents = mmap(NULL, contents_sz, PROT_READ,
 802                         MAP_PRIVATE, in_fd, 0);
 803                 close(in_fd);
 804
 805                 if (store.seen == 0)
 806                         store.seen = 1;
 807
 808                 for (i = 0, copy_begin = 0; i < store.seen; i++) {
 809                         if (store.offset[i] == 0) {
 810                                 store.offset[i] = copy_end = contents_sz;
 811                         } else if (store.state != KEY_SEEN) {
 812                                 copy_end = store.offset[i];
 813                         } else
 814                                 copy_end = find_beginning_of_line(
 815                                         contents, contents_sz,
 816                                         store.offset[i]-2, &new_line);
 817
 818                         if (copy_end > 0 && contents[copy_end-1] != '\n')
 819                                 new_line = 1;
 820
 821                         /* write the first part of the config */
 822                         if (copy_end > copy_begin) {
 823                                 if (write_in_full(fd, contents + copy_begin,
 824                                                   copy_end - copy_begin) <
 825                                     copy_end - copy_begin)
 826                                         goto write_err_out;
 827                                 if (new_line &&
 828                                     write_in_full(fd, "\n", 1) != 1)
 829                                         goto write_err_out;
 830                         }
 831                         copy_begin = store.offset[i];
 832                 }
 833
 834                 /* write the pair (value == NULL means unset) */
 835                 if (value != NULL) {
 836                         if (store.state == START) {
 837                                 if (!store_write_section(fd, key))
 838                                         goto write_err_out;
 839                         }
 840                         if (!store_write_pair(fd, key, value))
 841                                 goto write_err_out;
 842                 }
 843
 844                 /* write the rest of the config */
 845                 if (copy_begin < contents_sz)
 846                         if (write_in_full(fd, contents + copy_begin,
 847                                           contents_sz - copy_begin) <
 848                             contents_sz - copy_begin)
 849                                 goto write_err_out;
 850
 851                 munmap(contents, contents_sz);
 852         }
 853
 854         ret = 0;
 855
 856 out_free:
 857         free(config_filename);
 858         return ret;
 859
 860 write_err_out:
 861         goto out_free;
 862
 863 }
 864
 865 /*
 866  * Call this to report error for your variable that should not
 867  * get a boolean value (i.e. "[my] var" means "true").
 868  */
 869 int config_error_nonbool(const char *var)
 870 {
 871         return error("Missing value for '%s'", var);
 872 }