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 "cache.h"
   9 #include "exec_cmd.h"
  10
  11 #define MAXNAME (256)
  12
  13 static FILE *config_file;
  14 static const char *config_file_name;
  15 static int config_linenr;
  16 static int config_file_eof;
  17 static int zlib_compression_seen;
  18
  19 static int get_next_char(void)
  20 {
  21         int c;
  22         FILE *f;
  23
  24         c = '\n';
  25         if ((f = config_file) != NULL) {
  26                 c = fgetc(f);
  27                 if (c == '\r') {
  28                         /* DOS like systems */
  29                         c = fgetc(f);
  30                         if (c != '\n') {
  31                                 ungetc(c, f);
  32                                 c = '\r';
  33                         }
  34                 }
  35                 if (c == '\n')
  36                         config_linenr++;
  37                 if (c == EOF) {
  38                         config_file_eof = 1;
  39                         c = '\n';
  40                 }
  41         }
  42         return c;
  43 }
  44
  45 static char *parse_value(void)
  46 {
  47         static char value[1024];
  48         int quote = 0, comment = 0, len = 0, space = 0;
  49
  50         for (;;) {
  51                 int c = get_next_char();
  52                 if (len >= sizeof(value))
  53                         return NULL;
  54                 if (c == '\n') {
  55                         if (quote)
  56                                 return NULL;
  57                         value[len] = 0;
  58                         return value;
  59                 }
  60                 if (comment)
  61                         continue;
  62                 if (isspace(c) && !quote) {
  63                         space = 1;
  64                         continue;
  65                 }
  66                 if (!quote) {
  67                         if (c == ';' || c == '#') {
  68                                 comment = 1;
  69                                 continue;
  70                         }
  71                 }
  72                 if (space) {
  73                         if (len)
  74                                 value[len++] = ' ';
  75                         space = 0;
  76                 }
  77                 if (c == '\\') {
  78                         c = get_next_char();
  79                         switch (c) {
  80                         case '\n':
  81                                 continue;
  82                         case 't':
  83                                 c = '\t';
  84                                 break;
  85                         case 'b':
  86                                 c = '\b';
  87                                 break;
  88                         case 'n':
  89                                 c = '\n';
  90                                 break;
  91                         /* Some characters escape as themselves */
  92                         case '\\': case '"':
  93                                 break;
  94                         /* Reject unknown escape sequences */
  95                         default:
  96                                 return NULL;
  97                         }
  98                         value[len++] = c;
  99                         continue;
 100                 }
 101                 if (c == '"') {
 102                         quote = 1-quote;
 103                         continue;
 104                 }
 105                 value[len++] = c;
 106         }
 107 }
 108
 109 static inline int iskeychar(int c)
 110 {
 111         return isalnum(c) || c == '-';
 112 }
 113
 114 static int get_value(config_fn_t fn, char *name, unsigned int len)
 115 {
 116         int c;
 117         char *value;
 118
 119         /* Get the full name */
 120         for (;;) {
 121                 c = get_next_char();
 122                 if (config_file_eof)
 123                         break;
 124                 if (!iskeychar(c))
 125                         break;
 126                 name[len++] = tolower(c);
 127                 if (len >= MAXNAME)
 128                         return -1;
 129         }
 130         name[len] = 0;
 131         while (c == ' ' || c == '\t')
 132                 c = get_next_char();
 133
 134         value = NULL;
 135         if (c != '\n') {
 136                 if (c != '=')
 137                         return -1;
 138                 value = parse_value();
 139                 if (!value)
 140                         return -1;
 141         }
 142         return fn(name, value);
 143 }
 144
 145 static int get_extended_base_var(char *name, int baselen, int c)
 146 {
 147         do {
 148                 if (c == '\n')
 149                         return -1;
 150                 c = get_next_char();
 151         } while (isspace(c));
 152
 153         /* We require the format to be '[base "extension"]' */
 154         if (c != '"')
 155                 return -1;
 156         name[baselen++] = '.';
 157
 158         for (;;) {
 159                 int c = get_next_char();
 160                 if (c == '\n')
 161                         return -1;
 162                 if (c == '"')
 163                         break;
 164                 if (c == '\\') {
 165                         c = get_next_char();
 166                         if (c == '\n')
 167                                 return -1;
 168                 }
 169                 name[baselen++] = c;
 170                 if (baselen > MAXNAME / 2)
 171                         return -1;
 172         }
 173
 174         /* Final ']' */
 175         if (get_next_char() != ']')
 176                 return -1;
 177         return baselen;
 178 }
 179
 180 static int get_base_var(char *name)
 181 {
 182         int baselen = 0;
 183
 184         for (;;) {
 185                 int c = get_next_char();
 186                 if (config_file_eof)
 187                         return -1;
 188                 if (c == ']')
 189                         return baselen;
 190                 if (isspace(c))
 191                         return get_extended_base_var(name, baselen, c);
 192                 if (!iskeychar(c) && c != '.')
 193                         return -1;
 194                 if (baselen > MAXNAME / 2)
 195                         return -1;
 196                 name[baselen++] = tolower(c);
 197         }
 198 }
 199
 200 static int git_parse_file(config_fn_t fn)
 201 {
 202         int comment = 0;
 203         int baselen = 0;
 204         static char var[MAXNAME];
 205
 206         for (;;) {
 207                 int c = get_next_char();
 208                 if (c == '\n') {
 209                         if (config_file_eof)
 210                                 return 0;
 211                         comment = 0;
 212                         continue;
 213                 }
 214                 if (comment || isspace(c))
 215                         continue;
 216                 if (c == '#' || c == ';') {
 217                         comment = 1;
 218                         continue;
 219                 }
 220                 if (c == '[') {
 221                         baselen = get_base_var(var);
 222                         if (baselen <= 0)
 223                                 break;
 224                         var[baselen++] = '.';
 225                         var[baselen] = 0;
 226                         continue;
 227                 }
 228                 if (!isalpha(c))
 229                         break;
 230                 var[baselen] = tolower(c);
 231                 if (get_value(fn, var, baselen+1) < 0)
 232                         break;
 233         }
 234         die("bad config file line %d in %s", config_linenr, config_file_name);
 235 }
 236
 237 static int parse_unit_factor(const char *end, unsigned long *val)
 238 {
 239         if (!*end)
 240                 return 1;
 241         else if (!strcasecmp(end, "k")) {
 242                 *val *= 1024;
 243                 return 1;
 244         }
 245         else if (!strcasecmp(end, "m")) {
 246                 *val *= 1024 * 1024;
 247                 return 1;
 248         }
 249         else if (!strcasecmp(end, "g")) {
 250                 *val *= 1024 * 1024 * 1024;
 251                 return 1;
 252         }
 253         return 0;
 254 }
 255
 256 int git_parse_long(const char *value, long *ret)
 257 {
 258         if (value && *value) {
 259                 char *end;
 260                 long val = strtol(value, &end, 0);
 261                 unsigned long factor = 1;
 262                 if (!parse_unit_factor(end, &factor))
 263                         return 0;
 264                 *ret = val * factor;
 265                 return 1;
 266         }
 267         return 0;
 268 }
 269
 270 int git_parse_ulong(const char *value, unsigned long *ret)
 271 {
 272         if (value && *value) {
 273                 char *end;
 274                 unsigned long val = strtoul(value, &end, 0);
 275                 if (!parse_unit_factor(end, &val))
 276                         return 0;
 277                 *ret = val;
 278                 return 1;
 279         }
 280         return 0;
 281 }
 282
 283 int git_config_int(const char *name, const char *value)
 284 {
 285         long ret;
 286         if (!git_parse_long(value, &ret))
 287                 die("bad config value for '%s' in %s", name, config_file_name);
 288         return ret;
 289 }
 290
 291 unsigned long git_config_ulong(const char *name, const char *value)
 292 {
 293         unsigned long ret;
 294         if (!git_parse_ulong(value, &ret))
 295                 die("bad config value for '%s' in %s", name, config_file_name);
 296         return ret;
 297 }
 298
 299 int git_config_bool(const char *name, const char *value)
 300 {
 301         if (!value)
 302                 return 1;
 303         if (!*value)
 304                 return 0;
 305         if (!strcasecmp(value, "true") || !strcasecmp(value, "yes"))
 306                 return 1;
 307         if (!strcasecmp(value, "false") || !strcasecmp(value, "no"))
 308                 return 0;
 309         return git_config_int(name, value) != 0;
 310 }
 311
 312 int git_default_config(const char *var, const char *value)
 313 {
 314         /* This needs a better name */
 315         if (!strcmp(var, "core.filemode")) {
 316                 trust_executable_bit = git_config_bool(var, value);
 317                 return 0;
 318         }
 319
 320         if (!strcmp(var, "core.quotepath")) {
 321                 quote_path_fully = git_config_bool(var, value);
 322                 return 0;
 323         }
 324
 325         if (!strcmp(var, "core.symlinks")) {
 326                 has_symlinks = git_config_bool(var, value);
 327                 return 0;
 328         }
 329
 330         if (!strcmp(var, "core.bare")) {
 331                 is_bare_repository_cfg = git_config_bool(var, value);
 332                 return 0;
 333         }
 334
 335         if (!strcmp(var, "core.ignorestat")) {
 336                 assume_unchanged = git_config_bool(var, value);
 337                 return 0;
 338         }
 339
 340         if (!strcmp(var, "core.prefersymlinkrefs")) {
 341                 prefer_symlink_refs = git_config_bool(var, value);
 342                 return 0;
 343         }
 344
 345         if (!strcmp(var, "core.logallrefupdates")) {
 346                 log_all_ref_updates = git_config_bool(var, value);
 347                 return 0;
 348         }
 349
 350         if (!strcmp(var, "core.warnambiguousrefs")) {
 351                 warn_ambiguous_refs = git_config_bool(var, value);
 352                 return 0;
 353         }
 354
 355         if (!strcmp(var, "core.loosecompression")) {
 356                 int level = git_config_int(var, value);
 357                 if (level == -1)
 358                         level = Z_DEFAULT_COMPRESSION;
 359                 else if (level < 0 || level > Z_BEST_COMPRESSION)
 360                         die("bad zlib compression level %d", level);
 361                 zlib_compression_level = level;
 362                 zlib_compression_seen = 1;
 363                 return 0;
 364         }
 365
 366         if (!strcmp(var, "core.compression")) {
 367                 int level = git_config_int(var, value);
 368                 if (level == -1)
 369                         level = Z_DEFAULT_COMPRESSION;
 370                 else if (level < 0 || level > Z_BEST_COMPRESSION)
 371                         die("bad zlib compression level %d", level);
 372                 core_compression_level = level;
 373                 core_compression_seen = 1;
 374                 if (!zlib_compression_seen)
 375                         zlib_compression_level = level;
 376                 return 0;
 377         }
 378
 379         if (!strcmp(var, "core.packedgitwindowsize")) {
 380                 int pgsz_x2 = getpagesize() * 2;
 381                 packed_git_window_size = git_config_int(var, value);
 382
 383                 /* This value must be multiple of (pagesize * 2) */
 384                 packed_git_window_size /= pgsz_x2;
 385                 if (packed_git_window_size < 1)
 386                         packed_git_window_size = 1;
 387                 packed_git_window_size *= pgsz_x2;
 388                 return 0;
 389         }
 390
 391         if (!strcmp(var, "core.packedgitlimit")) {
 392                 packed_git_limit = git_config_int(var, value);
 393                 return 0;
 394         }
 395
 396         if (!strcmp(var, "core.deltabasecachelimit")) {
 397                 delta_base_cache_limit = git_config_int(var, value);
 398                 return 0;
 399         }
 400
 401         if (!strcmp(var, "core.autocrlf")) {
 402                 if (value && !strcasecmp(value, "input")) {
 403                         auto_crlf = -1;
 404                         return 0;
 405                 }
 406                 auto_crlf = git_config_bool(var, value);
 407                 return 0;
 408         }
 409
 410         if (!strcmp(var, "user.name")) {
 411                 strlcpy(git_default_name, value, sizeof(git_default_name));
 412                 return 0;
 413         }
 414
 415         if (!strcmp(var, "user.email")) {
 416                 strlcpy(git_default_email, value, sizeof(git_default_email));
 417                 return 0;
 418         }
 419
 420         if (!strcmp(var, "i18n.commitencoding")) {
 421                 git_commit_encoding = xstrdup(value);
 422                 return 0;
 423         }
 424
 425         if (!strcmp(var, "i18n.logoutputencoding")) {
 426                 git_log_output_encoding = xstrdup(value);
 427                 return 0;
 428         }
 429
 430
 431         if (!strcmp(var, "pager.color") || !strcmp(var, "color.pager")) {
 432                 pager_use_color = git_config_bool(var,value);
 433                 return 0;
 434         }
 435
 436         if (!strcmp(var, "core.pager")) {
 437                 pager_program = xstrdup(value);
 438                 return 0;
 439         }
 440
 441         if (!strcmp(var, "core.editor")) {
 442                 editor_program = xstrdup(value);
 443                 return 0;
 444         }
 445
 446         if (!strcmp(var, "core.excludesfile")) {
 447                 if (!value)
 448                         die("core.excludesfile without value");
 449                 excludes_file = xstrdup(value);
 450                 return 0;
 451         }
 452
 453         if (!strcmp(var, "core.whitespace")) {
 454                 whitespace_rule_cfg = parse_whitespace_rule(value);
 455                 return 0;
 456         }
 457
 458         /* Add other config variables here and to Documentation/config.txt. */
 459         return 0;
 460 }
 461
 462 int git_config_from_file(config_fn_t fn, const char *filename)
 463 {
 464         int ret;
 465         FILE *f = fopen(filename, "r");
 466
 467         ret = -1;
 468         if (f) {
 469                 config_file = f;
 470                 config_file_name = filename;
 471                 config_linenr = 1;
 472                 config_file_eof = 0;
 473                 ret = git_parse_file(fn);
 474                 fclose(f);
 475                 config_file_name = NULL;
 476         }
 477         return ret;
 478 }
 479
 480 const char *git_etc_gitconfig(void)
 481 {
 482         static const char *system_wide;
 483         if (!system_wide) {
 484                 system_wide = ETC_GITCONFIG;
 485                 if (!is_absolute_path(system_wide)) {
 486                         /* interpret path relative to exec-dir */
 487                         const char *exec_path = git_exec_path();
 488                         system_wide = prefix_path(exec_path, strlen(exec_path),
 489                                                 system_wide);
 490                 }
 491         }
 492         return system_wide;
 493 }
 494
 495 int git_config(config_fn_t fn)
 496 {
 497         int ret = 0;
 498         char *repo_config = NULL;
 499         const char *home = NULL, *filename;
 500
 501         /* $GIT_CONFIG makes git read _only_ the given config file,
 502          * $GIT_CONFIG_LOCAL will make it process it in addition to the
 503          * global config file, the same way it would the per-repository
 504          * config file otherwise. */
 505         filename = getenv(CONFIG_ENVIRONMENT);
 506         if (!filename) {
 507                 if (!access(git_etc_gitconfig(), R_OK))
 508                         ret += git_config_from_file(fn, git_etc_gitconfig());
 509                 home = getenv("HOME");
 510                 filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
 511                 if (!filename)
 512                         filename = repo_config = xstrdup(git_path("config"));
 513         }
 514
 515         if (home) {
 516                 char *user_config = xstrdup(mkpath("%s/.gitconfig", home));
 517                 if (!access(user_config, R_OK))
 518                         ret = git_config_from_file(fn, user_config);
 519                 free(user_config);
 520         }
 521
 522         ret += git_config_from_file(fn, filename);
 523         free(repo_config);
 524         return ret;
 525 }
 526
 527 /*
 528  * Find all the stuff for git_config_set() below.
 529  */
 530
 531 #define MAX_MATCHES 512
 532
 533 static struct {
 534         int baselen;
 535         char* key;
 536         int do_not_match;
 537         regex_t* value_regex;
 538         int multi_replace;
 539         size_t offset[MAX_MATCHES];
 540         enum { START, SECTION_SEEN, SECTION_END_SEEN, KEY_SEEN } state;
 541         int seen;
 542 } store;
 543
 544 static int matches(const char* key, const char* value)
 545 {
 546         return !strcmp(key, store.key) &&
 547                 (store.value_regex == NULL ||
 548                  (store.do_not_match ^
 549                   !regexec(store.value_regex, value, 0, NULL, 0)));
 550 }
 551
 552 static int store_aux(const char* key, const char* value)
 553 {
 554         const char *ep;
 555         size_t section_len;
 556
 557         switch (store.state) {
 558         case KEY_SEEN:
 559                 if (matches(key, value)) {
 560                         if (store.seen == 1 && store.multi_replace == 0) {
 561                                 fprintf(stderr,
 562                                         "Warning: %s has multiple values\n",
 563                                         key);
 564                         } else if (store.seen >= MAX_MATCHES) {
 565                                 fprintf(stderr, "Too many matches\n");
 566                                 return 1;
 567                         }
 568
 569                         store.offset[store.seen] = ftell(config_file);
 570                         store.seen++;
 571                 }
 572                 break;
 573         case SECTION_SEEN:
 574                 /*
 575                  * What we are looking for is in store.key (both
 576                  * section and var), and its section part is baselen
 577                  * long.  We found key (again, both section and var).
 578                  * We would want to know if this key is in the same
 579                  * section as what we are looking for.  We already
 580                  * know we are in the same section as what should
 581                  * hold store.key.
 582                  */
 583                 ep = strrchr(key, '.');
 584                 section_len = ep - key;
 585
 586                 if ((section_len != store.baselen) ||
 587                     memcmp(key, store.key, section_len+1)) {
 588                         store.state = SECTION_END_SEEN;
 589                         break;
 590                 }
 591
 592                 /*
 593                  * Do not increment matches: this is no match, but we
 594                  * just made sure we are in the desired section.
 595                  */
 596                 store.offset[store.seen] = ftell(config_file);
 597                 /* fallthru */
 598         case SECTION_END_SEEN:
 599         case START:
 600                 if (matches(key, value)) {
 601                         store.offset[store.seen] = ftell(config_file);
 602                         store.state = KEY_SEEN;
 603                         store.seen++;
 604                 } else {
 605                         if (strrchr(key, '.') - key == store.baselen &&
 606                               !strncmp(key, store.key, store.baselen)) {
 607                                         store.state = SECTION_SEEN;
 608                                         store.offset[store.seen] = ftell(config_file);
 609                         }
 610                 }
 611         }
 612         return 0;
 613 }
 614
 615 static int write_error(void)
 616 {
 617         fprintf(stderr, "Failed to write new configuration file\n");
 618
 619         /* Same error code as "failed to rename". */
 620         return 4;
 621 }
 622
 623 static int store_write_section(int fd, const char* key)
 624 {
 625         const char *dot;
 626         int i, success;
 627         struct strbuf sb;
 628
 629         strbuf_init(&sb, 0);
 630         dot = memchr(key, '.', store.baselen);
 631         if (dot) {
 632                 strbuf_addf(&sb, "[%.*s \"", (int)(dot - key), key);
 633                 for (i = dot - key + 1; i < store.baselen; i++) {
 634                         if (key[i] == '"')
 635                                 strbuf_addch(&sb, '\\');
 636                         strbuf_addch(&sb, key[i]);
 637                 }
 638                 strbuf_addstr(&sb, "\"]\n");
 639         } else {
 640                 strbuf_addf(&sb, "[%.*s]\n", store.baselen, key);
 641         }
 642
 643         success = write_in_full(fd, sb.buf, sb.len) == sb.len;
 644         strbuf_release(&sb);
 645
 646         return success;
 647 }
 648
 649 static int store_write_pair(int fd, const char* key, const char* value)
 650 {
 651         int i, success;
 652         int length = strlen(key + store.baselen + 1);
 653         const char *quote = "";
 654         struct strbuf sb;
 655
 656         /*
 657          * Check to see if the value needs to be surrounded with a dq pair.
 658          * Note that problematic characters are always backslash-quoted; this
 659          * check is about not losing leading or trailing SP and strings that
 660          * follow beginning-of-comment characters (i.e. ';' and '#') by the
 661          * configuration parser.
 662          */
 663         if (value[0] == ' ')
 664                 quote = "\"";
 665         for (i = 0; value[i]; i++)
 666                 if (value[i] == ';' || value[i] == '#')
 667                         quote = "\"";
 668         if (i && value[i - 1] == ' ')
 669                 quote = "\"";
 670
 671         strbuf_init(&sb, 0);
 672         strbuf_addf(&sb, "\t%.*s = %s",
 673                     length, key + store.baselen + 1, quote);
 674
 675         for (i = 0; value[i]; i++)
 676                 switch (value[i]) {
 677                 case '\n':
 678                         strbuf_addstr(&sb, "\\n");
 679                         break;
 680                 case '\t':
 681                         strbuf_addstr(&sb, "\\t");
 682                         break;
 683                 case '"':
 684                 case '\\':
 685                         strbuf_addch(&sb, '\\');
 686                 default:
 687                         strbuf_addch(&sb, value[i]);
 688                         break;
 689                 }
 690         strbuf_addf(&sb, "%s\n", quote);
 691
 692         success = write_in_full(fd, sb.buf, sb.len) == sb.len;
 693         strbuf_release(&sb);
 694
 695         return success;
 696 }
 697
 698 static ssize_t find_beginning_of_line(const char* contents, size_t size,
 699         size_t offset_, int* found_bracket)
 700 {
 701         size_t equal_offset = size, bracket_offset = size;
 702         ssize_t offset;
 703
 704 contline:
 705         for (offset = offset_-2; offset > 0
 706                         && contents[offset] != '\n'; offset--)
 707                 switch (contents[offset]) {
 708                         case '=': equal_offset = offset; break;
 709                         case ']': bracket_offset = offset; break;
 710                 }
 711         if (offset > 0 && contents[offset-1] == '\\') {
 712                 offset_ = offset;
 713                 goto contline;
 714         }
 715         if (bracket_offset < equal_offset) {
 716                 *found_bracket = 1;
 717                 offset = bracket_offset+1;
 718         } else
 719                 offset++;
 720
 721         return offset;
 722 }
 723
 724 int git_config_set(const char* key, const char* value)
 725 {
 726         return git_config_set_multivar(key, value, NULL, 0);
 727 }
 728
 729 /*
 730  * If value==NULL, unset in (remove from) config,
 731  * if value_regex!=NULL, disregard key/value pairs where value does not match.
 732  * if multi_replace==0, nothing, or only one matching key/value is replaced,
 733  *     else all matching key/values (regardless how many) are removed,
 734  *     before the new pair is written.
 735  *
 736  * Returns 0 on success.
 737  *
 738  * This function does this:
 739  *
 740  * - it locks the config file by creating ".git/config.lock"
 741  *
 742  * - it then parses the config using store_aux() as validator to find
 743  *   the position on the key/value pair to replace. If it is to be unset,
 744  *   it must be found exactly once.
 745  *
 746  * - the config file is mmap()ed and the part before the match (if any) is
 747  *   written to the lock file, then the changed part and the rest.
 748  *
 749  * - the config file is removed and the lock file rename()d to it.
 750  *
 751  */
 752 int git_config_set_multivar(const char* key, const char* value,
 753         const char* value_regex, int multi_replace)
 754 {
 755         int i, dot;
 756         int fd = -1, in_fd;
 757         int ret;
 758         char* config_filename;
 759         struct lock_file *lock = NULL;
 760         const char* last_dot = strrchr(key, '.');
 761
 762         config_filename = getenv(CONFIG_ENVIRONMENT);
 763         if (!config_filename) {
 764                 config_filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
 765                 if (!config_filename)
 766                         config_filename  = git_path("config");
 767         }
 768         config_filename = xstrdup(config_filename);
 769
 770         /*
 771          * Since "key" actually contains the section name and the real
 772          * key name separated by a dot, we have to know where the dot is.
 773          */
 774
 775         if (last_dot == NULL) {
 776                 fprintf(stderr, "key does not contain a section: %s\n", key);
 777                 ret = 2;
 778                 goto out_free;
 779         }
 780         store.baselen = last_dot - key;
 781
 782         store.multi_replace = multi_replace;
 783
 784         /*
 785          * Validate the key and while at it, lower case it for matching.
 786          */
 787         store.key = xmalloc(strlen(key) + 1);
 788         dot = 0;
 789         for (i = 0; key[i]; i++) {
 790                 unsigned char c = key[i];
 791                 if (c == '.')
 792                         dot = 1;
 793                 /* Leave the extended basename untouched.. */
 794                 if (!dot || i > store.baselen) {
 795                         if (!iskeychar(c) || (i == store.baselen+1 && !isalpha(c))) {
 796                                 fprintf(stderr, "invalid key: %s\n", key);
 797                                 free(store.key);
 798                                 ret = 1;
 799                                 goto out_free;
 800                         }
 801                         c = tolower(c);
 802                 } else if (c == '\n') {
 803                         fprintf(stderr, "invalid key (newline): %s\n", key);
 804                         free(store.key);
 805                         ret = 1;
 806                         goto out_free;
 807                 }
 808                 store.key[i] = c;
 809         }
 810         store.key[i] = 0;
 811
 812         /*
 813          * The lock serves a purpose in addition to locking: the new
 814          * contents of .git/config will be written into it.
 815          */
 816         lock = xcalloc(sizeof(struct lock_file), 1);
 817         fd = hold_lock_file_for_update(lock, config_filename, 0);
 818         if (fd < 0) {
 819                 fprintf(stderr, "could not lock config file\n");
 820                 free(store.key);
 821                 ret = -1;
 822                 goto out_free;
 823         }
 824
 825         /*
 826          * If .git/config does not exist yet, write a minimal version.
 827          */
 828         in_fd = open(config_filename, O_RDONLY);
 829         if ( in_fd < 0 ) {
 830                 free(store.key);
 831
 832                 if ( ENOENT != errno ) {
 833                         error("opening %s: %s", config_filename,
 834                               strerror(errno));
 835                         ret = 3; /* same as "invalid config file" */
 836                         goto out_free;
 837                 }
 838                 /* if nothing to unset, error out */
 839                 if (value == NULL) {
 840                         ret = 5;
 841                         goto out_free;
 842                 }
 843
 844                 store.key = (char*)key;
 845                 if (!store_write_section(fd, key) ||
 846                     !store_write_pair(fd, key, value))
 847                         goto write_err_out;
 848         } else {
 849                 struct stat st;
 850                 char* contents;
 851                 size_t contents_sz, copy_begin, copy_end;
 852                 int i, new_line = 0;
 853
 854                 if (value_regex == NULL)
 855                         store.value_regex = NULL;
 856                 else {
 857                         if (value_regex[0] == '!') {
 858                                 store.do_not_match = 1;
 859                                 value_regex++;
 860                         } else
 861                                 store.do_not_match = 0;
 862
 863                         store.value_regex = (regex_t*)xmalloc(sizeof(regex_t));
 864                         if (regcomp(store.value_regex, value_regex,
 865                                         REG_EXTENDED)) {
 866                                 fprintf(stderr, "Invalid pattern: %s\n",
 867                                         value_regex);
 868                                 free(store.value_regex);
 869                                 ret = 6;
 870                                 goto out_free;
 871                         }
 872                 }
 873
 874                 store.offset[0] = 0;
 875                 store.state = START;
 876                 store.seen = 0;
 877
 878                 /*
 879                  * After this, store.offset will contain the *end* offset
 880                  * of the last match, or remain at 0 if no match was found.
 881                  * As a side effect, we make sure to transform only a valid
 882                  * existing config file.
 883                  */
 884                 if (git_config_from_file(store_aux, config_filename)) {
 885                         fprintf(stderr, "invalid config file\n");
 886                         free(store.key);
 887                         if (store.value_regex != NULL) {
 888                                 regfree(store.value_regex);
 889                                 free(store.value_regex);
 890                         }
 891                         ret = 3;
 892                         goto out_free;
 893                 }
 894
 895                 free(store.key);
 896                 if (store.value_regex != NULL) {
 897                         regfree(store.value_regex);
 898                         free(store.value_regex);
 899                 }
 900
 901                 /* if nothing to unset, or too many matches, error out */
 902                 if ((store.seen == 0 && value == NULL) ||
 903                                 (store.seen > 1 && multi_replace == 0)) {
 904                         ret = 5;
 905                         goto out_free;
 906                 }
 907
 908                 fstat(in_fd, &st);
 909                 contents_sz = xsize_t(st.st_size);
 910                 contents = xmmap(NULL, contents_sz, PROT_READ,
 911                         MAP_PRIVATE, in_fd, 0);
 912                 close(in_fd);
 913
 914                 if (store.seen == 0)
 915                         store.seen = 1;
 916
 917                 for (i = 0, copy_begin = 0; i < store.seen; i++) {
 918                         if (store.offset[i] == 0) {
 919                                 store.offset[i] = copy_end = contents_sz;
 920                         } else if (store.state != KEY_SEEN) {
 921                                 copy_end = store.offset[i];
 922                         } else
 923                                 copy_end = find_beginning_of_line(
 924                                         contents, contents_sz,
 925                                         store.offset[i]-2, &new_line);
 926
 927                         if (copy_end > 0 && contents[copy_end-1] != '\n')
 928                                 new_line = 1;
 929
 930                         /* write the first part of the config */
 931                         if (copy_end > copy_begin) {
 932                                 if (write_in_full(fd, contents + copy_begin,
 933                                                   copy_end - copy_begin) <
 934                                     copy_end - copy_begin)
 935                                         goto write_err_out;
 936                                 if (new_line &&
 937                                     write_in_full(fd, "\n", 1) != 1)
 938                                         goto write_err_out;
 939                         }
 940                         copy_begin = store.offset[i];
 941                 }
 942
 943                 /* write the pair (value == NULL means unset) */
 944                 if (value != NULL) {
 945                         if (store.state == START) {
 946                                 if (!store_write_section(fd, key))
 947                                         goto write_err_out;
 948                         }
 949                         if (!store_write_pair(fd, key, value))
 950                                 goto write_err_out;
 951                 }
 952
 953                 /* write the rest of the config */
 954                 if (copy_begin < contents_sz)
 955                         if (write_in_full(fd, contents + copy_begin,
 956                                           contents_sz - copy_begin) <
 957                             contents_sz - copy_begin)
 958                                 goto write_err_out;
 959
 960                 munmap(contents, contents_sz);
 961         }
 962
 963         if (commit_lock_file(lock) < 0) {
 964                 fprintf(stderr, "Cannot commit config file!\n");
 965                 ret = 4;
 966                 goto out_free;
 967         }
 968
 969         /*
 970          * lock is committed, so don't try to roll it back below.
 971          * NOTE: Since lockfile.c keeps a linked list of all created
 972          * lock_file structures, it isn't safe to free(lock).  It's
 973          * better to just leave it hanging around.
 974          */
 975         lock = NULL;
 976         ret = 0;
 977
 978 out_free:
 979         if (lock)
 980                 rollback_lock_file(lock);
 981         free(config_filename);
 982         return ret;
 983
 984 write_err_out:
 985         ret = write_error();
 986         goto out_free;
 987
 988 }
 989
 990 static int section_name_match (const char *buf, const char *name)
 991 {
 992         int i = 0, j = 0, dot = 0;
 993         for (; buf[i] && buf[i] != ']'; i++) {
 994                 if (!dot && isspace(buf[i])) {
 995                         dot = 1;
 996                         if (name[j++] != '.')
 997                                 break;
 998                         for (i++; isspace(buf[i]); i++)
 999                                 ; /* do nothing */
1000                         if (buf[i] != '"')
1001                                 break;
1002                         continue;
1003                 }
1004                 if (buf[i] == '\\' && dot)
1005                         i++;
1006                 else if (buf[i] == '"' && dot) {
1007                         for (i++; isspace(buf[i]); i++)
1008                                 ; /* do_nothing */
1009                         break;
1010                 }
1011                 if (buf[i] != name[j++])
1012                         break;
1013         }
1014         return (buf[i] == ']' && name[j] == 0);
1015 }
1016
1017 /* if new_name == NULL, the section is removed instead */
1018 int git_config_rename_section(const char *old_name, const char *new_name)
1019 {
1020         int ret = 0, remove = 0;
1021         char *config_filename;
1022         struct lock_file *lock = xcalloc(sizeof(struct lock_file), 1);
1023         int out_fd;
1024         char buf[1024];
1025
1026         config_filename = getenv(CONFIG_ENVIRONMENT);
1027         if (!config_filename) {
1028                 config_filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
1029                 if (!config_filename)
1030                         config_filename  = git_path("config");
1031         }
1032         config_filename = xstrdup(config_filename);
1033         out_fd = hold_lock_file_for_update(lock, config_filename, 0);
1034         if (out_fd < 0) {
1035                 ret = error("Could not lock config file!");
1036                 goto out;
1037         }
1038
1039         if (!(config_file = fopen(config_filename, "rb"))) {
1040                 /* no config file means nothing to rename, no error */
1041                 goto unlock_and_out;
1042         }
1043
1044         while (fgets(buf, sizeof(buf), config_file)) {
1045                 int i;
1046                 int length;
1047                 for (i = 0; buf[i] && isspace(buf[i]); i++)
1048                         ; /* do nothing */
1049                 if (buf[i] == '[') {
1050                         /* it's a section */
1051                         if (section_name_match (&buf[i+1], old_name)) {
1052                                 ret++;
1053                                 if (new_name == NULL) {
1054                                         remove = 1;
1055                                         continue;
1056                                 }
1057                                 store.baselen = strlen(new_name);
1058                                 if (!store_write_section(out_fd, new_name)) {
1059                                         ret = write_error();
1060                                         goto out;
1061                                 }
1062                                 continue;
1063                         }
1064                         remove = 0;
1065                 }
1066                 if (remove)
1067                         continue;
1068                 length = strlen(buf);
1069                 if (write_in_full(out_fd, buf, length) != length) {
1070                         ret = write_error();
1071                         goto out;
1072                 }
1073         }
1074         fclose(config_file);
1075  unlock_and_out:
1076         if (commit_lock_file(lock) < 0)
1077                         ret = error("Cannot commit config file!");
1078  out:
1079         free(config_filename);
1080         return ret;
1081 }