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 static void die_bad_config(const char *name)
 284 {
 285         if (config_file_name)
 286                 die("bad config value for '%s' in %s", name, config_file_name);
 287         die("bad config value for '%s'", name);
 288 }
 289
 290 int git_config_int(const char *name, const char *value)
 291 {
 292         long ret;
 293         if (!git_parse_long(value, &ret))
 294                 die_bad_config(name);
 295         return ret;
 296 }
 297
 298 unsigned long git_config_ulong(const char *name, const char *value)
 299 {
 300         unsigned long ret;
 301         if (!git_parse_ulong(value, &ret))
 302                 die_bad_config(name);
 303         return ret;
 304 }
 305
 306 int git_config_bool(const char *name, const char *value)
 307 {
 308         if (!value)
 309                 return 1;
 310         if (!*value)
 311                 return 0;
 312         if (!strcasecmp(value, "true") || !strcasecmp(value, "yes"))
 313                 return 1;
 314         if (!strcasecmp(value, "false") || !strcasecmp(value, "no"))
 315                 return 0;
 316         return git_config_int(name, value) != 0;
 317 }
 318
 319 int git_config_string(const char **dest, const char *var, const char *value)
 320 {
 321         if (!value)
 322                 return config_error_nonbool(var);
 323         *dest = xstrdup(value);
 324         return 0;
 325 }
 326
 327 int git_default_config(const char *var, const char *value)
 328 {
 329         /* This needs a better name */
 330         if (!strcmp(var, "core.filemode")) {
 331                 trust_executable_bit = git_config_bool(var, value);
 332                 return 0;
 333         }
 334
 335         if (!strcmp(var, "core.quotepath")) {
 336                 quote_path_fully = git_config_bool(var, value);
 337                 return 0;
 338         }
 339
 340         if (!strcmp(var, "core.symlinks")) {
 341                 has_symlinks = git_config_bool(var, value);
 342                 return 0;
 343         }
 344
 345         if (!strcmp(var, "core.bare")) {
 346                 is_bare_repository_cfg = git_config_bool(var, value);
 347                 return 0;
 348         }
 349
 350         if (!strcmp(var, "core.ignorestat")) {
 351                 assume_unchanged = git_config_bool(var, value);
 352                 return 0;
 353         }
 354
 355         if (!strcmp(var, "core.prefersymlinkrefs")) {
 356                 prefer_symlink_refs = git_config_bool(var, value);
 357                 return 0;
 358         }
 359
 360         if (!strcmp(var, "core.logallrefupdates")) {
 361                 log_all_ref_updates = git_config_bool(var, value);
 362                 return 0;
 363         }
 364
 365         if (!strcmp(var, "core.warnambiguousrefs")) {
 366                 warn_ambiguous_refs = git_config_bool(var, value);
 367                 return 0;
 368         }
 369
 370         if (!strcmp(var, "core.loosecompression")) {
 371                 int level = git_config_int(var, value);
 372                 if (level == -1)
 373                         level = Z_DEFAULT_COMPRESSION;
 374                 else if (level < 0 || level > Z_BEST_COMPRESSION)
 375                         die("bad zlib compression level %d", level);
 376                 zlib_compression_level = level;
 377                 zlib_compression_seen = 1;
 378                 return 0;
 379         }
 380
 381         if (!strcmp(var, "core.compression")) {
 382                 int level = git_config_int(var, value);
 383                 if (level == -1)
 384                         level = Z_DEFAULT_COMPRESSION;
 385                 else if (level < 0 || level > Z_BEST_COMPRESSION)
 386                         die("bad zlib compression level %d", level);
 387                 core_compression_level = level;
 388                 core_compression_seen = 1;
 389                 if (!zlib_compression_seen)
 390                         zlib_compression_level = level;
 391                 return 0;
 392         }
 393
 394         if (!strcmp(var, "core.packedgitwindowsize")) {
 395                 int pgsz_x2 = getpagesize() * 2;
 396                 packed_git_window_size = git_config_int(var, value);
 397
 398                 /* This value must be multiple of (pagesize * 2) */
 399                 packed_git_window_size /= pgsz_x2;
 400                 if (packed_git_window_size < 1)
 401                         packed_git_window_size = 1;
 402                 packed_git_window_size *= pgsz_x2;
 403                 return 0;
 404         }
 405
 406         if (!strcmp(var, "core.packedgitlimit")) {
 407                 packed_git_limit = git_config_int(var, value);
 408                 return 0;
 409         }
 410
 411         if (!strcmp(var, "core.deltabasecachelimit")) {
 412                 delta_base_cache_limit = git_config_int(var, value);
 413                 return 0;
 414         }
 415
 416         if (!strcmp(var, "core.autocrlf")) {
 417                 if (value && !strcasecmp(value, "input")) {
 418                         auto_crlf = -1;
 419                         return 0;
 420                 }
 421                 auto_crlf = git_config_bool(var, value);
 422                 return 0;
 423         }
 424
 425         if (!strcmp(var, "core.safecrlf")) {
 426                 if (value && !strcasecmp(value, "warn")) {
 427                         safe_crlf = SAFE_CRLF_WARN;
 428                         return 0;
 429                 }
 430                 safe_crlf = git_config_bool(var, value);
 431                 return 0;
 432         }
 433
 434         if (!strcmp(var, "user.name")) {
 435                 if (!value)
 436                         return config_error_nonbool(var);
 437                 strlcpy(git_default_name, value, sizeof(git_default_name));
 438                 return 0;
 439         }
 440
 441         if (!strcmp(var, "user.email")) {
 442                 if (!value)
 443                         return config_error_nonbool(var);
 444                 strlcpy(git_default_email, value, sizeof(git_default_email));
 445                 return 0;
 446         }
 447
 448         if (!strcmp(var, "i18n.commitencoding"))
 449                 return git_config_string(&git_commit_encoding, var, value);
 450
 451         if (!strcmp(var, "i18n.logoutputencoding"))
 452                 return git_config_string(&git_log_output_encoding, var, value);
 453
 454         if (!strcmp(var, "pager.color") || !strcmp(var, "color.pager")) {
 455                 pager_use_color = git_config_bool(var,value);
 456                 return 0;
 457         }
 458
 459         if (!strcmp(var, "core.pager"))
 460                 return git_config_string(&pager_program, var, value);
 461
 462         if (!strcmp(var, "core.editor"))
 463                 return git_config_string(&editor_program, var, value);
 464
 465         if (!strcmp(var, "core.excludesfile"))
 466                 return git_config_string(&excludes_file, var, value);
 467
 468         if (!strcmp(var, "core.whitespace")) {
 469                 if (!value)
 470                         return config_error_nonbool(var);
 471                 whitespace_rule_cfg = parse_whitespace_rule(value);
 472                 return 0;
 473         }
 474         if (!strcmp(var, "branch.autosetupmerge")) {
 475                 if (value && !strcasecmp(value, "always")) {
 476                         git_branch_track = BRANCH_TRACK_ALWAYS;
 477                         return 0;
 478                 }
 479                 git_branch_track = git_config_bool(var, value);
 480                 return 0;
 481         }
 482
 483         /* Add other config variables here and to Documentation/config.txt. */
 484         return 0;
 485 }
 486
 487 int git_config_from_file(config_fn_t fn, const char *filename)
 488 {
 489         int ret;
 490         FILE *f = fopen(filename, "r");
 491
 492         ret = -1;
 493         if (f) {
 494                 config_file = f;
 495                 config_file_name = filename;
 496                 config_linenr = 1;
 497                 config_file_eof = 0;
 498                 ret = git_parse_file(fn);
 499                 fclose(f);
 500                 config_file_name = NULL;
 501         }
 502         return ret;
 503 }
 504
 505 const char *git_etc_gitconfig(void)
 506 {
 507         static const char *system_wide;
 508         if (!system_wide) {
 509                 system_wide = ETC_GITCONFIG;
 510                 if (!is_absolute_path(system_wide)) {
 511                         /* interpret path relative to exec-dir */
 512                         struct strbuf d = STRBUF_INIT;
 513                         strbuf_addf(&d, "%s/%s", git_exec_path(), system_wide);
 514                         system_wide = strbuf_detach(&d, NULL);
 515                 }
 516         }
 517         return system_wide;
 518 }
 519
 520 int git_env_bool(const char *k, int def)
 521 {
 522         const char *v = getenv(k);
 523         return v ? git_config_bool(k, v) : def;
 524 }
 525
 526 int git_config_system(void)
 527 {
 528         return !git_env_bool("GIT_CONFIG_NOSYSTEM", 0);
 529 }
 530
 531 int git_config_global(void)
 532 {
 533         return !git_env_bool("GIT_CONFIG_NOGLOBAL", 0);
 534 }
 535
 536 int git_config(config_fn_t fn)
 537 {
 538         int ret = 0;
 539         char *repo_config = NULL;
 540         const char *home = NULL, *filename;
 541
 542         /* $GIT_CONFIG makes git read _only_ the given config file,
 543          * $GIT_CONFIG_LOCAL will make it process it in addition to the
 544          * global config file, the same way it would the per-repository
 545          * config file otherwise. */
 546         filename = getenv(CONFIG_ENVIRONMENT);
 547         if (!filename) {
 548                 if (git_config_system() && !access(git_etc_gitconfig(), R_OK))
 549                         ret += git_config_from_file(fn, git_etc_gitconfig());
 550                 home = getenv("HOME");
 551                 filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
 552                 if (!filename)
 553                         filename = repo_config = xstrdup(git_path("config"));
 554         }
 555
 556         if (git_config_global() && home) {
 557                 char *user_config = xstrdup(mkpath("%s/.gitconfig", home));
 558                 if (!access(user_config, R_OK))
 559                         ret = git_config_from_file(fn, user_config);
 560                 free(user_config);
 561         }
 562
 563         ret += git_config_from_file(fn, filename);
 564         free(repo_config);
 565         return ret;
 566 }
 567
 568 /*
 569  * Find all the stuff for git_config_set() below.
 570  */
 571
 572 #define MAX_MATCHES 512
 573
 574 static struct {
 575         int baselen;
 576         char* key;
 577         int do_not_match;
 578         enum {
 579                 VALUE_NONE,
 580                 VALUE_REGEX,
 581                 VALUE_STRING,
 582         } value_type;
 583         union {
 584                 regex_t* regex;
 585                 const char *string;
 586         } value;
 587         int multi_replace;
 588         size_t offset[MAX_MATCHES];
 589         enum { START, SECTION_SEEN, SECTION_END_SEEN, KEY_SEEN } state;
 590         int seen;
 591 } store;
 592
 593 static int matches(const char* key, const char* value)
 594 {
 595         if (strcmp(key, store.key))
 596                 return 0;
 597         switch(store.value_type) {
 598         case VALUE_NONE:
 599                 return 1;
 600         case VALUE_REGEX:
 601                 return store.do_not_match ^
 602                         !regexec(store.value.regex, value, 0, NULL, 0);
 603         case VALUE_STRING:
 604                 return store.do_not_match ^
 605                         !strcmp(value, store.value.string);
 606         }
 607         die("bug in config.c:matches");
 608 }
 609
 610 static int store_aux(const char* key, const char* value)
 611 {
 612         const char *ep;
 613         size_t section_len;
 614
 615         switch (store.state) {
 616         case KEY_SEEN:
 617                 if (matches(key, value)) {
 618                         if (store.seen == 1 && store.multi_replace == 0) {
 619                                 fprintf(stderr,
 620                                         "Warning: %s has multiple values\n",
 621                                         key);
 622                         } else if (store.seen >= MAX_MATCHES) {
 623                                 fprintf(stderr, "Too many matches\n");
 624                                 return 1;
 625                         }
 626
 627                         store.offset[store.seen] = ftell(config_file);
 628                         store.seen++;
 629                 }
 630                 break;
 631         case SECTION_SEEN:
 632                 /*
 633                  * What we are looking for is in store.key (both
 634                  * section and var), and its section part is baselen
 635                  * long.  We found key (again, both section and var).
 636                  * We would want to know if this key is in the same
 637                  * section as what we are looking for.  We already
 638                  * know we are in the same section as what should
 639                  * hold store.key.
 640                  */
 641                 ep = strrchr(key, '.');
 642                 section_len = ep - key;
 643
 644                 if ((section_len != store.baselen) ||
 645                     memcmp(key, store.key, section_len+1)) {
 646                         store.state = SECTION_END_SEEN;
 647                         break;
 648                 }
 649
 650                 /*
 651                  * Do not increment matches: this is no match, but we
 652                  * just made sure we are in the desired section.
 653                  */
 654                 store.offset[store.seen] = ftell(config_file);
 655                 /* fallthru */
 656         case SECTION_END_SEEN:
 657         case START:
 658                 if (matches(key, value)) {
 659                         store.offset[store.seen] = ftell(config_file);
 660                         store.state = KEY_SEEN;
 661                         store.seen++;
 662                 } else {
 663                         if (strrchr(key, '.') - key == store.baselen &&
 664                               !strncmp(key, store.key, store.baselen)) {
 665                                         store.state = SECTION_SEEN;
 666                                         store.offset[store.seen] = ftell(config_file);
 667                         }
 668                 }
 669         }
 670         return 0;
 671 }
 672
 673 static int write_error(void)
 674 {
 675         fprintf(stderr, "Failed to write new configuration file\n");
 676
 677         /* Same error code as "failed to rename". */
 678         return 4;
 679 }
 680
 681 static int store_write_section(int fd, const char* key)
 682 {
 683         const char *dot;
 684         int i, success;
 685         struct strbuf sb;
 686
 687         strbuf_init(&sb, 0);
 688         dot = memchr(key, '.', store.baselen);
 689         if (dot) {
 690                 strbuf_addf(&sb, "[%.*s \"", (int)(dot - key), key);
 691                 for (i = dot - key + 1; i < store.baselen; i++) {
 692                         if (key[i] == '"')
 693                                 strbuf_addch(&sb, '\\');
 694                         strbuf_addch(&sb, key[i]);
 695                 }
 696                 strbuf_addstr(&sb, "\"]\n");
 697         } else {
 698                 strbuf_addf(&sb, "[%.*s]\n", store.baselen, key);
 699         }
 700
 701         success = write_in_full(fd, sb.buf, sb.len) == sb.len;
 702         strbuf_release(&sb);
 703
 704         return success;
 705 }
 706
 707 static int store_write_pair(int fd, const char* key, const char* value)
 708 {
 709         int i, success;
 710         int length = strlen(key + store.baselen + 1);
 711         const char *quote = "";
 712         struct strbuf sb;
 713
 714         /*
 715          * Check to see if the value needs to be surrounded with a dq pair.
 716          * Note that problematic characters are always backslash-quoted; this
 717          * check is about not losing leading or trailing SP and strings that
 718          * follow beginning-of-comment characters (i.e. ';' and '#') by the
 719          * configuration parser.
 720          */
 721         if (value[0] == ' ')
 722                 quote = "\"";
 723         for (i = 0; value[i]; i++)
 724                 if (value[i] == ';' || value[i] == '#')
 725                         quote = "\"";
 726         if (i && value[i - 1] == ' ')
 727                 quote = "\"";
 728
 729         strbuf_init(&sb, 0);
 730         strbuf_addf(&sb, "\t%.*s = %s",
 731                     length, key + store.baselen + 1, quote);
 732
 733         for (i = 0; value[i]; i++)
 734                 switch (value[i]) {
 735                 case '\n':
 736                         strbuf_addstr(&sb, "\\n");
 737                         break;
 738                 case '\t':
 739                         strbuf_addstr(&sb, "\\t");
 740                         break;
 741                 case '"':
 742                 case '\\':
 743                         strbuf_addch(&sb, '\\');
 744                 default:
 745                         strbuf_addch(&sb, value[i]);
 746                         break;
 747                 }
 748         strbuf_addf(&sb, "%s\n", quote);
 749
 750         success = write_in_full(fd, sb.buf, sb.len) == sb.len;
 751         strbuf_release(&sb);
 752
 753         return success;
 754 }
 755
 756 static ssize_t find_beginning_of_line(const char* contents, size_t size,
 757         size_t offset_, int* found_bracket)
 758 {
 759         size_t equal_offset = size, bracket_offset = size;
 760         ssize_t offset;
 761
 762 contline:
 763         for (offset = offset_-2; offset > 0
 764                         && contents[offset] != '\n'; offset--)
 765                 switch (contents[offset]) {
 766                         case '=': equal_offset = offset; break;
 767                         case ']': bracket_offset = offset; break;
 768                 }
 769         if (offset > 0 && contents[offset-1] == '\\') {
 770                 offset_ = offset;
 771                 goto contline;
 772         }
 773         if (bracket_offset < equal_offset) {
 774                 *found_bracket = 1;
 775                 offset = bracket_offset+1;
 776         } else
 777                 offset++;
 778
 779         return offset;
 780 }
 781
 782 int git_config_set(const char* key, const char* value)
 783 {
 784         return git_config_set_multivar(key, value, NULL, 0, 0);
 785 }
 786
 787 /*
 788  * If value==NULL, unset in (remove from) config,
 789  * if value_match!=NULL, disregard key/value pairs where value does not match.
 790  * if multi_replace==0, nothing, or only one matching key/value is replaced,
 791  *     else all matching key/values (regardless how many) are removed,
 792  *     before the new pair is written.
 793  *
 794  * Returns 0 on success.
 795  *
 796  * This function does this:
 797  *
 798  * - it locks the config file by creating ".git/config.lock"
 799  *
 800  * - it then parses the config using store_aux() as validator to find
 801  *   the position on the key/value pair to replace. If it is to be unset,
 802  *   it must be found exactly once.
 803  *
 804  * - the config file is mmap()ed and the part before the match (if any) is
 805  *   written to the lock file, then the changed part and the rest.
 806  *
 807  * - the config file is removed and the lock file rename()d to it.
 808  *
 809  */
 810 int git_config_set_multivar(const char* key, const char* value,
 811         const char* value_match, int literal_match, int multi_replace)
 812 {
 813         int i, dot;
 814         int fd = -1, in_fd;
 815         int ret;
 816         char* config_filename;
 817         struct lock_file *lock = NULL;
 818         const char* last_dot = strrchr(key, '.');
 819
 820         config_filename = getenv(CONFIG_ENVIRONMENT);
 821         if (!config_filename) {
 822                 config_filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
 823                 if (!config_filename)
 824                         config_filename  = git_path("config");
 825         }
 826         config_filename = xstrdup(config_filename);
 827
 828         /*
 829          * Since "key" actually contains the section name and the real
 830          * key name separated by a dot, we have to know where the dot is.
 831          */
 832
 833         if (last_dot == NULL) {
 834                 fprintf(stderr, "key does not contain a section: %s\n", key);
 835                 ret = 2;
 836                 goto out_free;
 837         }
 838         store.baselen = last_dot - key;
 839
 840         store.multi_replace = multi_replace;
 841
 842         /*
 843          * Validate the key and while at it, lower case it for matching.
 844          */
 845         store.key = xmalloc(strlen(key) + 1);
 846         dot = 0;
 847         for (i = 0; key[i]; i++) {
 848                 unsigned char c = key[i];
 849                 if (c == '.')
 850                         dot = 1;
 851                 /* Leave the extended basename untouched.. */
 852                 if (!dot || i > store.baselen) {
 853                         if (!iskeychar(c) || (i == store.baselen+1 && !isalpha(c))) {
 854                                 fprintf(stderr, "invalid key: %s\n", key);
 855                                 free(store.key);
 856                                 ret = 1;
 857                                 goto out_free;
 858                         }
 859                         c = tolower(c);
 860                 } else if (c == '\n') {
 861                         fprintf(stderr, "invalid key (newline): %s\n", key);
 862                         free(store.key);
 863                         ret = 1;
 864                         goto out_free;
 865                 }
 866                 store.key[i] = c;
 867         }
 868         store.key[i] = 0;
 869
 870         /*
 871          * The lock serves a purpose in addition to locking: the new
 872          * contents of .git/config will be written into it.
 873          */
 874         lock = xcalloc(sizeof(struct lock_file), 1);
 875         fd = hold_lock_file_for_update(lock, config_filename, 0);
 876         if (fd < 0) {
 877                 fprintf(stderr, "could not lock config file\n");
 878                 free(store.key);
 879                 ret = -1;
 880                 goto out_free;
 881         }
 882
 883         /*
 884          * If .git/config does not exist yet, write a minimal version.
 885          */
 886         in_fd = open(config_filename, O_RDONLY);
 887         if ( in_fd < 0 ) {
 888                 free(store.key);
 889
 890                 if ( ENOENT != errno ) {
 891                         error("opening %s: %s", config_filename,
 892                               strerror(errno));
 893                         ret = 3; /* same as "invalid config file" */
 894                         goto out_free;
 895                 }
 896                 /* if nothing to unset, error out */
 897                 if (value == NULL) {
 898                         ret = 5;
 899                         goto out_free;
 900                 }
 901
 902                 store.key = (char*)key;
 903                 if (!store_write_section(fd, key) ||
 904                     !store_write_pair(fd, key, value))
 905                         goto write_err_out;
 906         } else {
 907                 struct stat st;
 908                 char* contents;
 909                 size_t contents_sz, copy_begin, copy_end;
 910                 int i, new_line = 0;
 911
 912                 if (value_match == NULL)
 913                         store.value_type = VALUE_NONE;
 914                 else if(literal_match) {
 915                         store.value_type = VALUE_STRING;
 916                         store.do_not_match = 0;
 917                         store.value.string = value_match;
 918                 }
 919                 else {
 920                         store.value_type = VALUE_REGEX;
 921                         if (value_match[0] == '!') {
 922                                 store.do_not_match = 1;
 923                                 value_match++;
 924                         } else
 925                                 store.do_not_match = 0;
 926
 927                         store.value.regex = (regex_t*)xmalloc(sizeof(regex_t));
 928                         if (regcomp(store.value.regex, value_match,
 929                                         REG_EXTENDED)) {
 930                                 fprintf(stderr, "Invalid pattern: %s\n",
 931                                         value_match);
 932                                 free(store.value.regex);
 933                                 ret = 6;
 934                                 goto out_free;
 935                         }
 936                 }
 937
 938                 store.offset[0] = 0;
 939                 store.state = START;
 940                 store.seen = 0;
 941
 942                 /*
 943                  * After this, store.offset will contain the *end* offset
 944                  * of the last match, or remain at 0 if no match was found.
 945                  * As a side effect, we make sure to transform only a valid
 946                  * existing config file.
 947                  */
 948                 if (git_config_from_file(store_aux, config_filename)) {
 949                         fprintf(stderr, "invalid config file\n");
 950                         free(store.key);
 951                         if (store.value_type == VALUE_REGEX) {
 952                                 regfree(store.value.regex);
 953                                 free(store.value.regex);
 954                         }
 955                         ret = 3;
 956                         goto out_free;
 957                 }
 958
 959                 free(store.key);
 960                 if (store.value_type == VALUE_REGEX) {
 961                         regfree(store.value.regex);
 962                         free(store.value.regex);
 963                 }
 964
 965                 /* if nothing to unset, or too many matches, error out */
 966                 if ((store.seen == 0 && value == NULL) ||
 967                                 (store.seen > 1 && multi_replace == 0)) {
 968                         ret = 5;
 969                         goto out_free;
 970                 }
 971
 972                 fstat(in_fd, &st);
 973                 contents_sz = xsize_t(st.st_size);
 974                 contents = xmmap(NULL, contents_sz, PROT_READ,
 975                         MAP_PRIVATE, in_fd, 0);
 976                 close(in_fd);
 977
 978                 if (store.seen == 0)
 979                         store.seen = 1;
 980
 981                 for (i = 0, copy_begin = 0; i < store.seen; i++) {
 982                         if (store.offset[i] == 0) {
 983                                 store.offset[i] = copy_end = contents_sz;
 984                         } else if (store.state != KEY_SEEN) {
 985                                 copy_end = store.offset[i];
 986                         } else
 987                                 copy_end = find_beginning_of_line(
 988                                         contents, contents_sz,
 989                                         store.offset[i]-2, &new_line);
 990
 991                         if (copy_end > 0 && contents[copy_end-1] != '\n')
 992                                 new_line = 1;
 993
 994                         /* write the first part of the config */
 995                         if (copy_end > copy_begin) {
 996                                 if (write_in_full(fd, contents + copy_begin,
 997                                                   copy_end - copy_begin) <
 998                                     copy_end - copy_begin)
 999                                         goto write_err_out;
1000                                 if (new_line &&
1001                                     write_in_full(fd, "\n", 1) != 1)
1002                                         goto write_err_out;
1003                         }
1004                         copy_begin = store.offset[i];
1005                 }
1006
1007                 /* write the pair (value == NULL means unset) */
1008                 if (value != NULL) {
1009                         if (store.state == START) {
1010                                 if (!store_write_section(fd, key))
1011                                         goto write_err_out;
1012                         }
1013                         if (!store_write_pair(fd, key, value))
1014                                 goto write_err_out;
1015                 }
1016
1017                 /* write the rest of the config */
1018                 if (copy_begin < contents_sz)
1019                         if (write_in_full(fd, contents + copy_begin,
1020                                           contents_sz - copy_begin) <
1021                             contents_sz - copy_begin)
1022                                 goto write_err_out;
1023
1024                 munmap(contents, contents_sz);
1025         }
1026
1027         if (commit_lock_file(lock) < 0) {
1028                 fprintf(stderr, "Cannot commit config file!\n");
1029                 ret = 4;
1030                 goto out_free;
1031         }
1032
1033         /*
1034          * lock is committed, so don't try to roll it back below.
1035          * NOTE: Since lockfile.c keeps a linked list of all created
1036          * lock_file structures, it isn't safe to free(lock).  It's
1037          * better to just leave it hanging around.
1038          */
1039         lock = NULL;
1040         ret = 0;
1041
1042 out_free:
1043         if (lock)
1044                 rollback_lock_file(lock);
1045         free(config_filename);
1046         return ret;
1047
1048 write_err_out:
1049         ret = write_error();
1050         goto out_free;
1051
1052 }
1053
1054 static int section_name_match (const char *buf, const char *name)
1055 {
1056         int i = 0, j = 0, dot = 0;
1057         for (; buf[i] && buf[i] != ']'; i++) {
1058                 if (!dot && isspace(buf[i])) {
1059                         dot = 1;
1060                         if (name[j++] != '.')
1061                                 break;
1062                         for (i++; isspace(buf[i]); i++)
1063                                 ; /* do nothing */
1064                         if (buf[i] != '"')
1065                                 break;
1066                         continue;
1067                 }
1068                 if (buf[i] == '\\' && dot)
1069                         i++;
1070                 else if (buf[i] == '"' && dot) {
1071                         for (i++; isspace(buf[i]); i++)
1072                                 ; /* do_nothing */
1073                         break;
1074                 }
1075                 if (buf[i] != name[j++])
1076                         break;
1077         }
1078         return (buf[i] == ']' && name[j] == 0);
1079 }
1080
1081 /* if new_name == NULL, the section is removed instead */
1082 int git_config_rename_section(const char *old_name, const char *new_name)
1083 {
1084         int ret = 0, remove = 0;
1085         char *config_filename;
1086         struct lock_file *lock = xcalloc(sizeof(struct lock_file), 1);
1087         int out_fd;
1088         char buf[1024];
1089
1090         config_filename = getenv(CONFIG_ENVIRONMENT);
1091         if (!config_filename) {
1092                 config_filename = getenv(CONFIG_LOCAL_ENVIRONMENT);
1093                 if (!config_filename)
1094                         config_filename  = git_path("config");
1095         }
1096         config_filename = xstrdup(config_filename);
1097         out_fd = hold_lock_file_for_update(lock, config_filename, 0);
1098         if (out_fd < 0) {
1099                 ret = error("Could not lock config file!");
1100                 goto out;
1101         }
1102
1103         if (!(config_file = fopen(config_filename, "rb"))) {
1104                 /* no config file means nothing to rename, no error */
1105                 goto unlock_and_out;
1106         }
1107
1108         while (fgets(buf, sizeof(buf), config_file)) {
1109                 int i;
1110                 int length;
1111                 for (i = 0; buf[i] && isspace(buf[i]); i++)
1112                         ; /* do nothing */
1113                 if (buf[i] == '[') {
1114                         /* it's a section */
1115                         if (section_name_match (&buf[i+1], old_name)) {
1116                                 ret++;
1117                                 if (new_name == NULL) {
1118                                         remove = 1;
1119                                         continue;
1120                                 }
1121                                 store.baselen = strlen(new_name);
1122                                 if (!store_write_section(out_fd, new_name)) {
1123                                         ret = write_error();
1124                                         goto out;
1125                                 }
1126                                 continue;
1127                         }
1128                         remove = 0;
1129                 }
1130                 if (remove)
1131                         continue;
1132                 length = strlen(buf);
1133                 if (write_in_full(out_fd, buf, length) != length) {
1134                         ret = write_error();
1135                         goto out;
1136                 }
1137         }
1138         fclose(config_file);
1139  unlock_and_out:
1140         if (commit_lock_file(lock) < 0)
1141                         ret = error("Cannot commit config file!");
1142  out:
1143         free(config_filename);
1144         return ret;
1145 }
1146
1147 /*
1148  * Call this to report error for your variable that should not
1149  * get a boolean value (i.e. "[my] var" means "true").
1150  */
1151 int config_error_nonbool(const char *var)
1152 {
1153         return error("Missing value for '%s'", var);
1154 }