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 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, len = 0, space = 0;
  51
  52         for (;;) {
  53                 int c = get_next_char();
  54                 if (len >= sizeof(value))
  55                         return NULL;
  56                 if (c == '\n') {
  57                         if (quote)
  58                                 return NULL;
  59                         value[len] = 0;
  60                         return value;
  61                 }
  62                 if (comment)
  63                         continue;
  64                 if (isspace(c) && !quote) {
  65                         space = 1;
  66                         continue;
  67                 }
  68                 if (!quote) {
  69                         if (c == ';' || c == '#') {
  70                                 comment = 1;
  71                                 continue;
  72                         }
  73                 }
  74                 if (space) {
  75                         if (len)
  76                                 value[len++] = ' ';
  77                         space = 0;
  78                 }
  79                 if (c == '\\') {
  80                         c = get_next_char();
  81                         switch (c) {
  82                         case '\n':
  83                                 continue;
  84                         case 't':
  85                                 c = '\t';
  86                                 break;
  87                         case 'b':
  88                                 c = '\b';
  89                                 break;
  90                         case 'n':
  91                                 c = '\n';
  92                                 break;
  93                         /* Some characters escape as themselves */
  94                         case '\\': case '"':
  95                                 break;
  96                         /* Reject unknown escape sequences */
  97                         default:
  98                                 return NULL;
  99                         }
 100                         value[len++] = c;
 101                         continue;
 102                 }
 103                 if (c == '"') {
 104                         quote = 1-quote;
 105                         continue;
 106                 }
 107                 value[len++] = c;
 108         }
 109 }
 110
 111 static inline int iskeychar(int c)
 112 {
 113         return isalnum(c) || c == '-';
 114 }
 115
 116 static int get_value(config_fn_t fn, void *data, char *name, unsigned int len)
 117 {
 118         int c;
 119         char *value;
 120
 121         /* Get the full name */
 122         for (;;) {
 123                 c = get_next_char();
 124                 if (config_file_eof)
 125                         break;
 126                 if (!iskeychar(c))
 127                         break;
 128                 name[len++] = tolower(c);
 129                 if (len >= MAXNAME)
 130                         return -1;
 131         }
 132         name[len] = 0;
 133         while (c == ' ' || c == '\t')
 134                 c = get_next_char();
 135
 136         value = NULL;
 137         if (c != '\n') {
 138                 if (c != '=')
 139                         return -1;
 140                 value = parse_value();
 141                 if (!value)
 142                         return -1;
 143         }
 144         return fn(name, value, data);
 145 }
 146
 147 static int get_extended_base_var(char *name, int baselen, int c)
 148 {
 149         do {
 150                 if (c == '\n')
 151                         return -1;
 152                 c = get_next_char();
 153         } while (isspace(c));
 154
 155         /* We require the format to be '[base "extension"]' */
 156         if (c != '"')
 157                 return -1;
 158         name[baselen++] = '.';
 159
 160         for (;;) {
 161                 int c = get_next_char();
 162                 if (c == '\n')
 163                         return -1;
 164                 if (c == '"')
 165                         break;
 166                 if (c == '\\') {
 167                         c = get_next_char();
 168                         if (c == '\n')
 169                                 return -1;
 170                 }
 171                 name[baselen++] = c;
 172                 if (baselen > MAXNAME / 2)
 173                         return -1;
 174         }
 175
 176         /* Final ']' */
 177         if (get_next_char() != ']')
 178                 return -1;
 179         return baselen;
 180 }
 181
 182 static int get_base_var(char *name)
 183 {
 184         int baselen = 0;
 185
 186         for (;;) {
 187                 int c = get_next_char();
 188                 if (config_file_eof)
 189                         return -1;
 190                 if (c == ']')
 191                         return baselen;
 192                 if (isspace(c))
 193                         return get_extended_base_var(name, baselen, c);
 194                 if (!iskeychar(c) && c != '.')
 195                         return -1;
 196                 if (baselen > MAXNAME / 2)
 197                         return -1;
 198                 name[baselen++] = tolower(c);
 199         }
 200 }
 201
 202 static int git_parse_file(config_fn_t fn, void *data)
 203 {
 204         int comment = 0;
 205         int baselen = 0;
 206         static char var[MAXNAME];
 207
 208         /* U+FEFF Byte Order Mark in UTF8 */
 209         static const unsigned char *utf8_bom = (unsigned char *) "\xef\xbb\xbf";
 210         const unsigned char *bomptr = utf8_bom;
 211
 212         for (;;) {
 213                 int c = get_next_char();
 214                 if (bomptr && *bomptr) {
 215                         /* We are at the file beginning; skip UTF8-encoded BOM
 216                          * if present. Sane editors won't put this in on their
 217                          * own, but e.g. Windows Notepad will do it happily. */
 218                         if ((unsigned char) c == *bomptr) {
 219                                 bomptr++;
 220                                 continue;
 221                         } else {
 222                                 /* Do not tolerate partial BOM. */
 223                                 if (bomptr != utf8_bom)
 224                                         break;
 225                                 /* No BOM at file beginning. Cool. */
 226                                 bomptr = NULL;
 227                         }
 228                 }
 229                 if (c == '\n') {
 230                         if (config_file_eof)
 231                                 return 0;
 232                         comment = 0;
 233                         continue;
 234                 }
 235                 if (comment || isspace(c))
 236                         continue;
 237                 if (c == '#' || c == ';') {
 238                         comment = 1;
 239                         continue;
 240                 }
 241                 if (c == '[') {
 242                         baselen = get_base_var(var);
 243                         if (baselen <= 0)
 244                                 break;
 245                         var[baselen++] = '.';
 246                         var[baselen] = 0;
 247                         continue;
 248                 }
 249                 if (!isalpha(c))
 250                         break;
 251                 var[baselen] = tolower(c);
 252                 if (get_value(fn, data, var, baselen+1) < 0)
 253                         break;
 254         }
 255         die("bad config file line %d in %s", config_linenr, config_file_name);
 256 }
 257
 258 static int parse_unit_factor(const char *end, unsigned long *val)
 259 {
 260         if (!*end)
 261                 return 1;
 262         else if (!strcasecmp(end, "k")) {
 263                 *val *= 1024;
 264                 return 1;
 265         }
 266         else if (!strcasecmp(end, "m")) {
 267                 *val *= 1024 * 1024;
 268                 return 1;
 269         }
 270         else if (!strcasecmp(end, "g")) {
 271                 *val *= 1024 * 1024 * 1024;
 272                 return 1;
 273         }
 274         return 0;
 275 }
 276
 277 static int git_parse_long(const char *value, long *ret)
 278 {
 279         if (value && *value) {
 280                 char *end;
 281                 long val = strtol(value, &end, 0);
 282                 unsigned long factor = 1;
 283                 if (!parse_unit_factor(end, &factor))
 284                         return 0;
 285                 *ret = val * factor;
 286                 return 1;
 287         }
 288         return 0;
 289 }
 290
 291 int git_parse_ulong(const char *value, unsigned long *ret)
 292 {
 293         if (value && *value) {
 294                 char *end;
 295                 unsigned long val = strtoul(value, &end, 0);
 296                 if (!parse_unit_factor(end, &val))
 297                         return 0;
 298                 *ret = val;
 299                 return 1;
 300         }
 301         return 0;
 302 }
 303
 304 static void die_bad_config(const char *name)
 305 {
 306         if (config_file_name)
 307                 die("bad config value for '%s' in %s", name, config_file_name);
 308         die("bad config value for '%s'", name);
 309 }
 310
 311 int git_config_int(const char *name, const char *value)
 312 {
 313         long ret = 0;
 314         if (!git_parse_long(value, &ret))
 315                 die_bad_config(name);
 316         return ret;
 317 }
 318
 319 unsigned long git_config_ulong(const char *name, const char *value)
 320 {
 321         unsigned long ret;
 322         if (!git_parse_ulong(value, &ret))
 323                 die_bad_config(name);
 324         return ret;
 325 }
 326
 327 int git_config_bool_or_int(const char *name, const char *value, int *is_bool)
 328 {
 329         *is_bool = 1;
 330         if (!value)
 331                 return 1;
 332         if (!*value)
 333                 return 0;
 334         if (!strcasecmp(value, "true") || !strcasecmp(value, "yes"))
 335                 return 1;
 336         if (!strcasecmp(value, "false") || !strcasecmp(value, "no"))
 337                 return 0;
 338         *is_bool = 0;
 339         return git_config_int(name, value);
 340 }
 341
 342 int git_config_bool(const char *name, const char *value)
 343 {
 344         int discard;
 345         return !!git_config_bool_or_int(name, value, &discard);
 346 }
 347
 348 int git_config_string(const char **dest, const char *var, const char *value)
 349 {
 350         if (!value)
 351                 return config_error_nonbool(var);
 352         *dest = xstrdup(value);
 353         return 0;
 354 }
 355
 356 static int git_default_core_config(const char *var, const char *value)
 357 {
 358         /* This needs a better name */
 359         if (!strcmp(var, "core.filemode")) {
 360                 trust_executable_bit = git_config_bool(var, value);
 361                 return 0;
 362         }
 363         if (!strcmp(var, "core.trustctime")) {
 364                 trust_ctime = git_config_bool(var, value);
 365                 return 0;
 366         }
 367
 368         if (!strcmp(var, "core.quotepath")) {
 369                 quote_path_fully = git_config_bool(var, value);
 370                 return 0;
 371         }
 372
 373         if (!strcmp(var, "core.symlinks")) {
 374                 has_symlinks = git_config_bool(var, value);
 375                 return 0;
 376         }
 377
 378         if (!strcmp(var, "core.ignorecase")) {
 379                 ignore_case = git_config_bool(var, value);
 380                 return 0;
 381         }
 382
 383         if (!strcmp(var, "core.bare")) {
 384                 is_bare_repository_cfg = git_config_bool(var, value);
 385                 return 0;
 386         }
 387
 388         if (!strcmp(var, "core.ignorestat")) {
 389                 assume_unchanged = git_config_bool(var, value);
 390                 return 0;
 391         }
 392
 393         if (!strcmp(var, "core.prefersymlinkrefs")) {
 394                 prefer_symlink_refs = git_config_bool(var, value);
 395                 return 0;
 396         }
 397
 398         if (!strcmp(var, "core.logallrefupdates")) {
 399                 log_all_ref_updates = git_config_bool(var, value);
 400                 return 0;
 401         }
 402
 403         if (!strcmp(var, "core.warnambiguousrefs")) {
 404                 warn_ambiguous_refs = git_config_bool(var, value);
 405                 return 0;
 406         }
 407
 408         if (!strcmp(var, "core.loosecompression")) {
 409                 int level = git_config_int(var, value);
 410                 if (level == -1)
 411                         level = Z_DEFAULT_COMPRESSION;
 412                 else if (level < 0 || level > Z_BEST_COMPRESSION)
 413                         die("bad zlib compression level %d", level);
 414                 zlib_compression_level = level;
 415                 zlib_compression_seen = 1;
 416                 return 0;
 417         }
 418
 419         if (!strcmp(var, "core.compression")) {
 420                 int level = git_config_int(var, value);
 421                 if (level == -1)
 422                         level = Z_DEFAULT_COMPRESSION;
 423                 else if (level < 0 || level > Z_BEST_COMPRESSION)
 424                         die("bad zlib compression level %d", level);
 425                 core_compression_level = level;
 426                 core_compression_seen = 1;
 427                 if (!zlib_compression_seen)
 428                         zlib_compression_level = level;
 429                 return 0;
 430         }
 431
 432         if (!strcmp(var, "core.packedgitwindowsize")) {
 433                 int pgsz_x2 = getpagesize() * 2;
 434                 packed_git_window_size = git_config_int(var, value);
 435
 436                 /* This value must be multiple of (pagesize * 2) */
 437                 packed_git_window_size /= pgsz_x2;
 438                 if (packed_git_window_size < 1)
 439                         packed_git_window_size = 1;
 440                 packed_git_window_size *= pgsz_x2;
 441                 return 0;
 442         }
 443
 444         if (!strcmp(var, "core.packedgitlimit")) {
 445                 packed_git_limit = git_config_int(var, value);
 446                 return 0;
 447         }
 448
 449         if (!strcmp(var, "core.deltabasecachelimit")) {
 450                 delta_base_cache_limit = git_config_int(var, value);
 451                 return 0;
 452         }
 453
 454         if (!strcmp(var, "core.autocrlf")) {
 455                 if (value && !strcasecmp(value, "input")) {
 456                         auto_crlf = -1;
 457                         return 0;
 458                 }
 459                 auto_crlf = git_config_bool(var, value);
 460                 return 0;
 461         }
 462
 463         if (!strcmp(var, "core.safecrlf")) {
 464                 if (value && !strcasecmp(value, "warn")) {
 465                         safe_crlf = SAFE_CRLF_WARN;
 466                         return 0;
 467                 }
 468                 safe_crlf = git_config_bool(var, value);
 469                 return 0;
 470         }
 471
 472         if (!strcmp(var, "core.pager"))
 473                 return git_config_string(&pager_program, var, value);
 474
 475         if (!strcmp(var, "core.editor"))
 476                 return git_config_string(&editor_program, var, value);
 477
 478         if (!strcmp(var, "core.excludesfile"))
 479                 return git_config_string(&excludes_file, var, value);
 480
 481         if (!strcmp(var, "core.whitespace")) {
 482                 if (!value)
 483                         return config_error_nonbool(var);
 484                 whitespace_rule_cfg = parse_whitespace_rule(value);
 485                 return 0;
 486         }
 487
 488         if (!strcmp(var, "core.fsyncobjectfiles")) {
 489                 fsync_object_files = git_config_bool(var, value);
 490                 return 0;
 491         }
 492
 493         /* Add other config variables here and to Documentation/config.txt. */
 494         return 0;
 495 }
 496
 497 static int git_default_user_config(const char *var, const char *value)
 498 {
 499         if (!strcmp(var, "user.name")) {
 500                 if (!value)
 501                         return config_error_nonbool(var);
 502                 strlcpy(git_default_name, value, sizeof(git_default_name));
 503                 if (git_default_email[0])
 504                         user_ident_explicitly_given = 1;
 505                 return 0;
 506         }
 507
 508         if (!strcmp(var, "user.email")) {
 509                 if (!value)
 510                         return config_error_nonbool(var);
 511                 strlcpy(git_default_email, value, sizeof(git_default_email));
 512                 if (git_default_name[0])
 513                         user_ident_explicitly_given = 1;
 514                 return 0;
 515         }
 516
 517         /* Add other config variables here and to Documentation/config.txt. */
 518         return 0;
 519 }
 520
 521 static int git_default_i18n_config(const char *var, const char *value)
 522 {
 523         if (!strcmp(var, "i18n.commitencoding"))
 524                 return git_config_string(&git_commit_encoding, var, value);
 525
 526         if (!strcmp(var, "i18n.logoutputencoding"))
 527                 return git_config_string(&git_log_output_encoding, var, value);
 528
 529         /* Add other config variables here and to Documentation/config.txt. */
 530         return 0;
 531 }
 532
 533 static int git_default_branch_config(const char *var, const char *value)
 534 {
 535         if (!strcmp(var, "branch.autosetupmerge")) {
 536                 if (value && !strcasecmp(value, "always")) {
 537                         git_branch_track = BRANCH_TRACK_ALWAYS;
 538                         return 0;
 539                 }
 540                 git_branch_track = git_config_bool(var, value);
 541                 return 0;
 542         }
 543         if (!strcmp(var, "branch.autosetuprebase")) {
 544                 if (!value)
 545                         return config_error_nonbool(var);
 546                 else if (!strcmp(value, "never"))
 547                         autorebase = AUTOREBASE_NEVER;
 548                 else if (!strcmp(value, "local"))
 549                         autorebase = AUTOREBASE_LOCAL;
 550                 else if (!strcmp(value, "remote"))
 551                         autorebase = AUTOREBASE_REMOTE;
 552                 else if (!strcmp(value, "always"))
 553                         autorebase = AUTOREBASE_ALWAYS;
 554                 else
 555                         return error("Malformed value for %s", var);
 556                 return 0;
 557         }
 558
 559         /* Add other config variables here and to Documentation/config.txt. */
 560         return 0;
 561 }
 562
 563 int git_default_config(const char *var, const char *value, void *dummy)
 564 {
 565         if (!prefixcmp(var, "core."))
 566                 return git_default_core_config(var, value);
 567
 568         if (!prefixcmp(var, "user."))
 569                 return git_default_user_config(var, value);
 570
 571         if (!prefixcmp(var, "i18n."))
 572                 return git_default_i18n_config(var, value);
 573
 574         if (!prefixcmp(var, "branch."))
 575                 return git_default_branch_config(var, value);
 576
 577         if (!strcmp(var, "pager.color") || !strcmp(var, "color.pager")) {
 578                 pager_use_color = git_config_bool(var,value);
 579                 return 0;
 580         }
 581
 582         /* Add other config variables here and to Documentation/config.txt. */
 583         return 0;
 584 }
 585
 586 int git_config_from_file(config_fn_t fn, const char *filename, void *data)
 587 {
 588         int ret;
 589         FILE *f = fopen(filename, "r");
 590
 591         ret = -1;
 592         if (f) {
 593                 config_file = f;
 594                 config_file_name = filename;
 595                 config_linenr = 1;
 596                 config_file_eof = 0;
 597                 ret = git_parse_file(fn, data);
 598                 fclose(f);
 599                 config_file_name = NULL;
 600         }
 601         return ret;
 602 }
 603
 604 const char *git_etc_gitconfig(void)
 605 {
 606         static const char *system_wide;
 607         if (!system_wide)
 608                 system_wide = system_path(ETC_GITCONFIG);
 609         return system_wide;
 610 }
 611
 612 static int git_env_bool(const char *k, int def)
 613 {
 614         const char *v = getenv(k);
 615         return v ? git_config_bool(k, v) : def;
 616 }
 617
 618 int git_config_system(void)
 619 {
 620         return !git_env_bool("GIT_CONFIG_NOSYSTEM", 0);
 621 }
 622
 623 int git_config_global(void)
 624 {
 625         return !git_env_bool("GIT_CONFIG_NOGLOBAL", 0);
 626 }
 627
 628 int git_config(config_fn_t fn, void *data)
 629 {
 630         int ret = 0;
 631         char *repo_config = NULL;
 632         const char *home = NULL;
 633
 634         /* $GIT_CONFIG makes git read _only_ the given config file,
 635          * $GIT_CONFIG_LOCAL will make it process it in addition to the
 636          * global config file, the same way it would the per-repository
 637          * config file otherwise. */
 638         if (config_exclusive_filename)
 639                 return git_config_from_file(fn, config_exclusive_filename, data);
 640         if (git_config_system() && !access(git_etc_gitconfig(), R_OK))
 641                 ret += git_config_from_file(fn, git_etc_gitconfig(),
 642                                             data);
 643
 644         home = getenv("HOME");
 645         if (git_config_global() && home) {
 646                 char *user_config = xstrdup(mkpath("%s/.gitconfig", home));
 647                 if (!access(user_config, R_OK))
 648                         ret += git_config_from_file(fn, user_config, data);
 649                 free(user_config);
 650         }
 651
 652         repo_config = xstrdup(git_path("config"));
 653         ret += git_config_from_file(fn, repo_config, data);
 654         free(repo_config);
 655         return ret;
 656 }
 657
 658 /*
 659  * Find all the stuff for git_config_set() below.
 660  */
 661
 662 #define MAX_MATCHES 512
 663
 664 static struct {
 665         int baselen;
 666         char* key;
 667         int do_not_match;
 668         regex_t* value_regex;
 669         int multi_replace;
 670         size_t offset[MAX_MATCHES];
 671         enum { START, SECTION_SEEN, SECTION_END_SEEN, KEY_SEEN } state;
 672         int seen;
 673 } store;
 674
 675 static int matches(const char* key, const char* value)
 676 {
 677         return !strcmp(key, store.key) &&
 678                 (store.value_regex == NULL ||
 679                  (store.do_not_match ^
 680                   !regexec(store.value_regex, value, 0, NULL, 0)));
 681 }
 682
 683 static int store_aux(const char* key, const char* value, void *cb)
 684 {
 685         const char *ep;
 686         size_t section_len;
 687
 688         switch (store.state) {
 689         case KEY_SEEN:
 690                 if (matches(key, value)) {
 691                         if (store.seen == 1 && store.multi_replace == 0) {
 692                                 warning("%s has multiple values", key);
 693                         } else if (store.seen >= MAX_MATCHES) {
 694                                 error("too many matches for %s", key);
 695                                 return 1;
 696                         }
 697
 698                         store.offset[store.seen] = ftell(config_file);
 699                         store.seen++;
 700                 }
 701                 break;
 702         case SECTION_SEEN:
 703                 /*
 704                  * What we are looking for is in store.key (both
 705                  * section and var), and its section part is baselen
 706                  * long.  We found key (again, both section and var).
 707                  * We would want to know if this key is in the same
 708                  * section as what we are looking for.  We already
 709                  * know we are in the same section as what should
 710                  * hold store.key.
 711                  */
 712                 ep = strrchr(key, '.');
 713                 section_len = ep - key;
 714
 715                 if ((section_len != store.baselen) ||
 716                     memcmp(key, store.key, section_len+1)) {
 717                         store.state = SECTION_END_SEEN;
 718                         break;
 719                 }
 720
 721                 /*
 722                  * Do not increment matches: this is no match, but we
 723                  * just made sure we are in the desired section.
 724                  */
 725                 store.offset[store.seen] = ftell(config_file);
 726                 /* fallthru */
 727         case SECTION_END_SEEN:
 728         case START:
 729                 if (matches(key, value)) {
 730                         store.offset[store.seen] = ftell(config_file);
 731                         store.state = KEY_SEEN;
 732                         store.seen++;
 733                 } else {
 734                         if (strrchr(key, '.') - key == store.baselen &&
 735                               !strncmp(key, store.key, store.baselen)) {
 736                                         store.state = SECTION_SEEN;
 737                                         store.offset[store.seen] = ftell(config_file);
 738                         }
 739                 }
 740         }
 741         return 0;
 742 }
 743
 744 static int write_error(const char *filename)
 745 {
 746         error("failed to write new configuration file %s", filename);
 747
 748         /* Same error code as "failed to rename". */
 749         return 4;
 750 }
 751
 752 static int store_write_section(int fd, const char* key)
 753 {
 754         const char *dot;
 755         int i, success;
 756         struct strbuf sb;
 757
 758         strbuf_init(&sb, 0);
 759         dot = memchr(key, '.', store.baselen);
 760         if (dot) {
 761                 strbuf_addf(&sb, "[%.*s \"", (int)(dot - key), key);
 762                 for (i = dot - key + 1; i < store.baselen; i++) {
 763                         if (key[i] == '"' || key[i] == '\\')
 764                                 strbuf_addch(&sb, '\\');
 765                         strbuf_addch(&sb, key[i]);
 766                 }
 767                 strbuf_addstr(&sb, "\"]\n");
 768         } else {
 769                 strbuf_addf(&sb, "[%.*s]\n", store.baselen, key);
 770         }
 771
 772         success = write_in_full(fd, sb.buf, sb.len) == sb.len;
 773         strbuf_release(&sb);
 774
 775         return success;
 776 }
 777
 778 static int store_write_pair(int fd, const char* key, const char* value)
 779 {
 780         int i, success;
 781         int length = strlen(key + store.baselen + 1);
 782         const char *quote = "";
 783         struct strbuf sb;
 784
 785         /*
 786          * Check to see if the value needs to be surrounded with a dq pair.
 787          * Note that problematic characters are always backslash-quoted; this
 788          * check is about not losing leading or trailing SP and strings that
 789          * follow beginning-of-comment characters (i.e. ';' and '#') by the
 790          * configuration parser.
 791          */
 792         if (value[0] == ' ')
 793                 quote = "\"";
 794         for (i = 0; value[i]; i++)
 795                 if (value[i] == ';' || value[i] == '#')
 796                         quote = "\"";
 797         if (i && value[i - 1] == ' ')
 798                 quote = "\"";
 799
 800         strbuf_init(&sb, 0);
 801         strbuf_addf(&sb, "\t%.*s = %s",
 802                     length, key + store.baselen + 1, quote);
 803
 804         for (i = 0; value[i]; i++)
 805                 switch (value[i]) {
 806                 case '\n':
 807                         strbuf_addstr(&sb, "\\n");
 808                         break;
 809                 case '\t':
 810                         strbuf_addstr(&sb, "\\t");
 811                         break;
 812                 case '"':
 813                 case '\\':
 814                         strbuf_addch(&sb, '\\');
 815                 default:
 816                         strbuf_addch(&sb, value[i]);
 817                         break;
 818                 }
 819         strbuf_addf(&sb, "%s\n", quote);
 820
 821         success = write_in_full(fd, sb.buf, sb.len) == sb.len;
 822         strbuf_release(&sb);
 823
 824         return success;
 825 }
 826
 827 static ssize_t find_beginning_of_line(const char* contents, size_t size,
 828         size_t offset_, int* found_bracket)
 829 {
 830         size_t equal_offset = size, bracket_offset = size;
 831         ssize_t offset;
 832
 833 contline:
 834         for (offset = offset_-2; offset > 0
 835                         && contents[offset] != '\n'; offset--)
 836                 switch (contents[offset]) {
 837                         case '=': equal_offset = offset; break;
 838                         case ']': bracket_offset = offset; break;
 839                 }
 840         if (offset > 0 && contents[offset-1] == '\\') {
 841                 offset_ = offset;
 842                 goto contline;
 843         }
 844         if (bracket_offset < equal_offset) {
 845                 *found_bracket = 1;
 846                 offset = bracket_offset+1;
 847         } else
 848                 offset++;
 849
 850         return offset;
 851 }
 852
 853 int git_config_set(const char* key, const char* value)
 854 {
 855         return git_config_set_multivar(key, value, NULL, 0);
 856 }
 857
 858 /*
 859  * If value==NULL, unset in (remove from) config,
 860  * if value_regex!=NULL, disregard key/value pairs where value does not match.
 861  * if multi_replace==0, nothing, or only one matching key/value is replaced,
 862  *     else all matching key/values (regardless how many) are removed,
 863  *     before the new pair is written.
 864  *
 865  * Returns 0 on success.
 866  *
 867  * This function does this:
 868  *
 869  * - it locks the config file by creating ".git/config.lock"
 870  *
 871  * - it then parses the config using store_aux() as validator to find
 872  *   the position on the key/value pair to replace. If it is to be unset,
 873  *   it must be found exactly once.
 874  *
 875  * - the config file is mmap()ed and the part before the match (if any) is
 876  *   written to the lock file, then the changed part and the rest.
 877  *
 878  * - the config file is removed and the lock file rename()d to it.
 879  *
 880  */
 881 int git_config_set_multivar(const char* key, const char* value,
 882         const char* value_regex, int multi_replace)
 883 {
 884         int i, dot;
 885         int fd = -1, in_fd;
 886         int ret;
 887         char* config_filename;
 888         struct lock_file *lock = NULL;
 889         const char* last_dot = strrchr(key, '.');
 890
 891         if (config_exclusive_filename)
 892                 config_filename = xstrdup(config_exclusive_filename);
 893         else
 894                 config_filename = xstrdup(git_path("config"));
 895
 896         /*
 897          * Since "key" actually contains the section name and the real
 898          * key name separated by a dot, we have to know where the dot is.
 899          */
 900
 901         if (last_dot == NULL) {
 902                 error("key does not contain a section: %s", key);
 903                 ret = 2;
 904                 goto out_free;
 905         }
 906         store.baselen = last_dot - key;
 907
 908         store.multi_replace = multi_replace;
 909
 910         /*
 911          * Validate the key and while at it, lower case it for matching.
 912          */
 913         store.key = xmalloc(strlen(key) + 1);
 914         dot = 0;
 915         for (i = 0; key[i]; i++) {
 916                 unsigned char c = key[i];
 917                 if (c == '.')
 918                         dot = 1;
 919                 /* Leave the extended basename untouched.. */
 920                 if (!dot || i > store.baselen) {
 921                         if (!iskeychar(c) || (i == store.baselen+1 && !isalpha(c))) {
 922                                 error("invalid key: %s", key);
 923                                 free(store.key);
 924                                 ret = 1;
 925                                 goto out_free;
 926                         }
 927                         c = tolower(c);
 928                 } else if (c == '\n') {
 929                         error("invalid key (newline): %s", key);
 930                         free(store.key);
 931                         ret = 1;
 932                         goto out_free;
 933                 }
 934                 store.key[i] = c;
 935         }
 936         store.key[i] = 0;
 937
 938         /*
 939          * The lock serves a purpose in addition to locking: the new
 940          * contents of .git/config will be written into it.
 941          */
 942         lock = xcalloc(sizeof(struct lock_file), 1);
 943         fd = hold_lock_file_for_update(lock, config_filename, 0);
 944         if (fd < 0) {
 945                 error("could not lock config file %s", config_filename);
 946                 free(store.key);
 947                 ret = -1;
 948                 goto out_free;
 949         }
 950
 951         /*
 952          * If .git/config does not exist yet, write a minimal version.
 953          */
 954         in_fd = open(config_filename, O_RDONLY);
 955         if ( in_fd < 0 ) {
 956                 free(store.key);
 957
 958                 if ( ENOENT != errno ) {
 959                         error("opening %s: %s", config_filename,
 960                               strerror(errno));
 961                         ret = 3; /* same as "invalid config file" */
 962                         goto out_free;
 963                 }
 964                 /* if nothing to unset, error out */
 965                 if (value == NULL) {
 966                         ret = 5;
 967                         goto out_free;
 968                 }
 969
 970                 store.key = (char*)key;
 971                 if (!store_write_section(fd, key) ||
 972                     !store_write_pair(fd, key, value))
 973                         goto write_err_out;
 974         } else {
 975                 struct stat st;
 976                 char* contents;
 977                 size_t contents_sz, copy_begin, copy_end;
 978                 int i, new_line = 0;
 979
 980                 if (value_regex == NULL)
 981                         store.value_regex = NULL;
 982                 else {
 983                         if (value_regex[0] == '!') {
 984                                 store.do_not_match = 1;
 985                                 value_regex++;
 986                         } else
 987                                 store.do_not_match = 0;
 988
 989                         store.value_regex = (regex_t*)xmalloc(sizeof(regex_t));
 990                         if (regcomp(store.value_regex, value_regex,
 991                                         REG_EXTENDED)) {
 992                                 error("invalid pattern: %s", value_regex);
 993                                 free(store.value_regex);
 994                                 ret = 6;
 995                                 goto out_free;
 996                         }
 997                 }
 998
 999                 store.offset[0] = 0;
1000                 store.state = START;
1001                 store.seen = 0;
1002
1003                 /*
1004                  * After this, store.offset will contain the *end* offset
1005                  * of the last match, or remain at 0 if no match was found.
1006                  * As a side effect, we make sure to transform only a valid
1007                  * existing config file.
1008                  */
1009                 if (git_config_from_file(store_aux, config_filename, NULL)) {
1010                         error("invalid config file %s", config_filename);
1011                         free(store.key);
1012                         if (store.value_regex != NULL) {
1013                                 regfree(store.value_regex);
1014                                 free(store.value_regex);
1015                         }
1016                         ret = 3;
1017                         goto out_free;
1018                 }
1019
1020                 free(store.key);
1021                 if (store.value_regex != NULL) {
1022                         regfree(store.value_regex);
1023                         free(store.value_regex);
1024                 }
1025
1026                 /* if nothing to unset, or too many matches, error out */
1027                 if ((store.seen == 0 && value == NULL) ||
1028                                 (store.seen > 1 && multi_replace == 0)) {
1029                         ret = 5;
1030                         goto out_free;
1031                 }
1032
1033                 fstat(in_fd, &st);
1034                 contents_sz = xsize_t(st.st_size);
1035                 contents = xmmap(NULL, contents_sz, PROT_READ,
1036                         MAP_PRIVATE, in_fd, 0);
1037                 close(in_fd);
1038
1039                 if (store.seen == 0)
1040                         store.seen = 1;
1041
1042                 for (i = 0, copy_begin = 0; i < store.seen; i++) {
1043                         if (store.offset[i] == 0) {
1044                                 store.offset[i] = copy_end = contents_sz;
1045                         } else if (store.state != KEY_SEEN) {
1046                                 copy_end = store.offset[i];
1047                         } else
1048                                 copy_end = find_beginning_of_line(
1049                                         contents, contents_sz,
1050                                         store.offset[i]-2, &new_line);
1051
1052                         if (copy_end > 0 && contents[copy_end-1] != '\n')
1053                                 new_line = 1;
1054
1055                         /* write the first part of the config */
1056                         if (copy_end > copy_begin) {
1057                                 if (write_in_full(fd, contents + copy_begin,
1058                                                   copy_end - copy_begin) <
1059                                     copy_end - copy_begin)
1060                                         goto write_err_out;
1061                                 if (new_line &&
1062                                     write_in_full(fd, "\n", 1) != 1)
1063                                         goto write_err_out;
1064                         }
1065                         copy_begin = store.offset[i];
1066                 }
1067
1068                 /* write the pair (value == NULL means unset) */
1069                 if (value != NULL) {
1070                         if (store.state == START) {
1071                                 if (!store_write_section(fd, key))
1072                                         goto write_err_out;
1073                         }
1074                         if (!store_write_pair(fd, key, value))
1075                                 goto write_err_out;
1076                 }
1077
1078                 /* write the rest of the config */
1079                 if (copy_begin < contents_sz)
1080                         if (write_in_full(fd, contents + copy_begin,
1081                                           contents_sz - copy_begin) <
1082                             contents_sz - copy_begin)
1083                                 goto write_err_out;
1084
1085                 munmap(contents, contents_sz);
1086         }
1087
1088         if (commit_lock_file(lock) < 0) {
1089                 error("could not commit config file %s", config_filename);
1090                 ret = 4;
1091                 goto out_free;
1092         }
1093
1094         /*
1095          * lock is committed, so don't try to roll it back below.
1096          * NOTE: Since lockfile.c keeps a linked list of all created
1097          * lock_file structures, it isn't safe to free(lock).  It's
1098          * better to just leave it hanging around.
1099          */
1100         lock = NULL;
1101         ret = 0;
1102
1103 out_free:
1104         if (lock)
1105                 rollback_lock_file(lock);
1106         free(config_filename);
1107         return ret;
1108
1109 write_err_out:
1110         ret = write_error(lock->filename);
1111         goto out_free;
1112
1113 }
1114
1115 static int section_name_match (const char *buf, const char *name)
1116 {
1117         int i = 0, j = 0, dot = 0;
1118         for (; buf[i] && buf[i] != ']'; i++) {
1119                 if (!dot && isspace(buf[i])) {
1120                         dot = 1;
1121                         if (name[j++] != '.')
1122                                 break;
1123                         for (i++; isspace(buf[i]); i++)
1124                                 ; /* do nothing */
1125                         if (buf[i] != '"')
1126                                 break;
1127                         continue;
1128                 }
1129                 if (buf[i] == '\\' && dot)
1130                         i++;
1131                 else if (buf[i] == '"' && dot) {
1132                         for (i++; isspace(buf[i]); i++)
1133                                 ; /* do_nothing */
1134                         break;
1135                 }
1136                 if (buf[i] != name[j++])
1137                         break;
1138         }
1139         return (buf[i] == ']' && name[j] == 0);
1140 }
1141
1142 /* if new_name == NULL, the section is removed instead */
1143 int git_config_rename_section(const char *old_name, const char *new_name)
1144 {
1145         int ret = 0, remove = 0;
1146         char *config_filename;
1147         struct lock_file *lock = xcalloc(sizeof(struct lock_file), 1);
1148         int out_fd;
1149         char buf[1024];
1150
1151         if (config_exclusive_filename)
1152                 config_filename = xstrdup(config_exclusive_filename);
1153         else
1154                 config_filename = xstrdup(git_path("config"));
1155         out_fd = hold_lock_file_for_update(lock, config_filename, 0);
1156         if (out_fd < 0) {
1157                 ret = error("could not lock config file %s", config_filename);
1158                 goto out;
1159         }
1160
1161         if (!(config_file = fopen(config_filename, "rb"))) {
1162                 /* no config file means nothing to rename, no error */
1163                 goto unlock_and_out;
1164         }
1165
1166         while (fgets(buf, sizeof(buf), config_file)) {
1167                 int i;
1168                 int length;
1169                 for (i = 0; buf[i] && isspace(buf[i]); i++)
1170                         ; /* do nothing */
1171                 if (buf[i] == '[') {
1172                         /* it's a section */
1173                         if (section_name_match (&buf[i+1], old_name)) {
1174                                 ret++;
1175                                 if (new_name == NULL) {
1176                                         remove = 1;
1177                                         continue;
1178                                 }
1179                                 store.baselen = strlen(new_name);
1180                                 if (!store_write_section(out_fd, new_name)) {
1181                                         ret = write_error(lock->filename);
1182                                         goto out;
1183                                 }
1184                                 continue;
1185                         }
1186                         remove = 0;
1187                 }
1188                 if (remove)
1189                         continue;
1190                 length = strlen(buf);
1191                 if (write_in_full(out_fd, buf, length) != length) {
1192                         ret = write_error(lock->filename);
1193                         goto out;
1194                 }
1195         }
1196         fclose(config_file);
1197  unlock_and_out:
1198         if (commit_lock_file(lock) < 0)
1199                 ret = error("could not commit config file %s", config_filename);
1200  out:
1201         free(config_filename);
1202         return ret;
1203 }
1204
1205 /*
1206  * Call this to report error for your variable that should not
1207  * get a boolean value (i.e. "[my] var" means "true").
1208  */
1209 int config_error_nonbool(const char *var)
1210 {
1211         return error("Missing value for '%s'", var);
1212 }