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 <regex.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 get_next_char(void)
  17 {
  18         int c;
  19         FILE *f;
  20
  21         c = '\n';
  22         if ((f = config_file) != NULL) {
  23                 c = fgetc(f);
  24                 if (c == '\r') {
  25                         /* DOS like systems */
  26                         c = fgetc(f);
  27                         if (c != '\n') {
  28                                 ungetc(c, f);
  29                                 c = '\r';
  30                         }
  31                 }
  32                 if (c == '\n')
  33                         config_linenr++;
  34                 if (c == EOF) {
  35                         config_file = NULL;
  36                         c = '\n';
  37                 }
  38         }
  39         return c;
  40 }
  41
  42 static char *parse_value(void)
  43 {
  44         static char value[1024];
  45         int quote = 0, comment = 0, len = 0, space = 0;
  46
  47         for (;;) {
  48                 int c = get_next_char();
  49                 if (len >= sizeof(value))
  50                         return NULL;
  51                 if (c == '\n') {
  52                         if (quote)
  53                                 return NULL;
  54                         value[len] = 0;
  55                         return value;
  56                 }
  57                 if (comment)
  58                         continue;
  59                 if (isspace(c) && !quote) {
  60                         space = 1;
  61                         continue;
  62                 }
  63                 if (!quote) {
  64                         if (c == ';' || c == '#') {
  65                                 comment = 1;
  66                                 continue;
  67                         }
  68                 }
  69                 if (space) {
  70                         if (len)
  71                                 value[len++] = ' ';
  72                         space = 0;
  73                 }
  74                 if (c == '\\') {
  75                         c = get_next_char();
  76                         switch (c) {
  77                         case '\n':
  78                                 continue;
  79                         case 't':
  80                                 c = '\t';
  81                                 break;
  82                         case 'b':
  83                                 c = '\b';
  84                                 break;
  85                         case 'n':
  86                                 c = '\n';
  87                                 break;
  88                         /* Some characters escape as themselves */
  89                         case '\\': case '"':
  90                                 break;
  91                         /* Reject unknown escape sequences */
  92                         default:
  93                                 return NULL;
  94                         }
  95                         value[len++] = c;
  96                         continue;
  97                 }
  98                 if (c == '"') {
  99                         quote = 1-quote;
 100                         continue;
 101                 }
 102                 value[len++] = c;
 103         }
 104 }
 105
 106 static int get_value(config_fn_t fn, char *name, unsigned int len)
 107 {
 108         int c;
 109         char *value;
 110
 111         /* Get the full name */
 112         for (;;) {
 113                 c = get_next_char();
 114                 if (c == EOF)
 115                         break;
 116                 if (!isalnum(c))
 117                         break;
 118                 name[len++] = tolower(c);
 119                 if (len >= MAXNAME)
 120                         return -1;
 121         }
 122         name[len] = 0;
 123         while (c == ' ' || c == '\t')
 124                 c = get_next_char();
 125
 126         value = NULL;
 127         if (c != '\n') {
 128                 if (c != '=')
 129                         return -1;
 130                 value = parse_value();
 131                 if (!value)
 132                         return -1;
 133         }
 134         return fn(name, value);
 135 }
 136
 137 static int get_extended_base_var(char *name, int baselen, int c)
 138 {
 139         do {
 140                 if (c == '\n')
 141                         return -1;
 142                 c = get_next_char();
 143         } while (isspace(c));
 144
 145         /* We require the format to be '[base "extension"]' */
 146         if (c != '"')
 147                 return -1;
 148         name[baselen++] = '.';
 149
 150         for (;;) {
 151                 int c = get_next_char();
 152                 if (c == '\n')
 153                         return -1;
 154                 if (c == '"')
 155                         break;
 156                 if (c == '\\') {
 157                         c = get_next_char();
 158                         if (c == '\n')
 159                                 return -1;
 160                 }
 161                 name[baselen++] = c;
 162                 if (baselen > MAXNAME / 2)
 163                         return -1;
 164         }
 165
 166         /* Final ']' */
 167         if (get_next_char() != ']')
 168                 return -1;
 169         return baselen;
 170 }
 171
 172 static int get_base_var(char *name)
 173 {
 174         int baselen = 0;
 175
 176         for (;;) {
 177                 int c = get_next_char();
 178                 if (c == EOF)
 179                         return -1;
 180                 if (c == ']')
 181                         return baselen;
 182                 if (isspace(c))
 183                         return get_extended_base_var(name, baselen, c);
 184                 if (!isalnum(c) && c != '.')
 185                         return -1;
 186                 if (baselen > MAXNAME / 2)
 187                         return -1;
 188                 name[baselen++] = tolower(c);
 189         }
 190 }
 191
 192 static int git_parse_file(config_fn_t fn)
 193 {
 194         int comment = 0;
 195         int baselen = 0;
 196         static char var[MAXNAME];
 197
 198         for (;;) {
 199                 int c = get_next_char();
 200                 if (c == '\n') {
 201                         /* EOF? */
 202                         if (!config_file)
 203                                 return 0;
 204                         comment = 0;
 205                         continue;
 206                 }
 207                 if (comment || isspace(c))
 208                         continue;
 209                 if (c == '#' || c == ';') {
 210                         comment = 1;
 211                         continue;
 212                 }
 213                 if (c == '[') {
 214                         baselen = get_base_var(var);
 215                         if (baselen <= 0)
 216                                 break;
 217                         var[baselen++] = '.';
 218                         var[baselen] = 0;
 219                         continue;
 220                 }
 221                 if (!isalpha(c))
 222                         break;
 223                 var[baselen] = tolower(c);
 224                 if (get_value(fn, var, baselen+1) < 0)
 225                         break;
 226         }
 227         die("bad config file line %d in %s", config_linenr, config_file_name);
 228 }
 229
 230 int git_config_int(const char *name, const char *value)
 231 {
 232         if (value && *value) {
 233                 char *end;
 234                 int val = strtol(value, &end, 0);
 235                 if (!*end)
 236                         return val;
 237         }
 238         die("bad config value for '%s' in %s", name, config_file_name);
 239 }
 240
 241 int git_config_bool(const char *name, const char *value)
 242 {
 243         if (!value)
 244                 return 1;
 245         if (!*value)
 246                 return 0;
 247         if (!strcasecmp(value, "true"))
 248                 return 1;
 249         if (!strcasecmp(value, "false"))
 250                 return 0;
 251         return git_config_int(name, value) != 0;
 252 }
 253
 254 int git_default_config(const char *var, const char *value)
 255 {
 256         /* This needs a better name */
 257         if (!strcmp(var, "core.filemode")) {
 258                 trust_executable_bit = git_config_bool(var, value);
 259                 return 0;
 260         }
 261
 262         if (!strcmp(var, "core.ignorestat")) {
 263                 assume_unchanged = git_config_bool(var, value);
 264                 return 0;
 265         }
 266
 267         if (!strcmp(var, "core.prefersymlinkrefs")) {
 268                 prefer_symlink_refs = git_config_bool(var, value);
 269                 return 0;
 270         }
 271
 272         if (!strcmp(var, "core.warnambiguousrefs")) {
 273                 warn_ambiguous_refs = git_config_bool(var, value);
 274                 return 0;
 275         }
 276
 277         if (!strcmp(var, "user.name")) {
 278                 strncpy(git_default_name, value, sizeof(git_default_name));
 279                 return 0;
 280         }
 281
 282         if (!strcmp(var, "user.email")) {
 283                 strncpy(git_default_email, value, sizeof(git_default_email));
 284                 return 0;
 285         }
 286
 287         if (!strcmp(var, "i18n.commitencoding")) {
 288                 strncpy(git_commit_encoding, value, sizeof(git_commit_encoding));
 289                 return 0;
 290         }
 291
 292         /* Add other config variables here and to Documentation/config.txt. */
 293         return 0;
 294 }
 295
 296 int git_config_from_file(config_fn_t fn, const char *filename)
 297 {
 298         int ret;
 299         FILE *f = fopen(filename, "r");
 300
 301         ret = -1;
 302         if (f) {
 303                 config_file = f;
 304                 config_file_name = filename;
 305                 config_linenr = 1;
 306                 ret = git_parse_file(fn);
 307                 fclose(f);
 308                 config_file_name = NULL;
 309         }
 310         return ret;
 311 }
 312
 313 int git_config(config_fn_t fn)
 314 {
 315         return git_config_from_file(fn, git_path("config"));
 316 }
 317
 318 /*
 319  * Find all the stuff for git_config_set() below.
 320  */
 321
 322 #define MAX_MATCHES 512
 323
 324 static struct {
 325         int baselen;
 326         char* key;
 327         int do_not_match;
 328         regex_t* value_regex;
 329         int multi_replace;
 330         off_t offset[MAX_MATCHES];
 331         enum { START, SECTION_SEEN, SECTION_END_SEEN, KEY_SEEN } state;
 332         int seen;
 333 } store;
 334
 335 static int matches(const char* key, const char* value)
 336 {
 337         return !strcmp(key, store.key) &&
 338                 (store.value_regex == NULL ||
 339                  (store.do_not_match ^
 340                   !regexec(store.value_regex, value, 0, NULL, 0)));
 341 }
 342
 343 static int store_aux(const char* key, const char* value)
 344 {
 345         switch (store.state) {
 346         case KEY_SEEN:
 347                 if (matches(key, value)) {
 348                         if (store.seen == 1 && store.multi_replace == 0) {
 349                                 fprintf(stderr,
 350                                         "Warning: %s has multiple values\n",
 351                                         key);
 352                         } else if (store.seen >= MAX_MATCHES) {
 353                                 fprintf(stderr, "Too many matches\n");
 354                                 return 1;
 355                         }
 356
 357                         store.offset[store.seen] = ftell(config_file);
 358                         store.seen++;
 359                 }
 360                 break;
 361         case SECTION_SEEN:
 362                 if (strncmp(key, store.key, store.baselen+1)) {
 363                         store.state = SECTION_END_SEEN;
 364                         break;
 365                 } else
 366                         /* do not increment matches: this is no match */
 367                         store.offset[store.seen] = ftell(config_file);
 368                 /* fallthru */
 369         case SECTION_END_SEEN:
 370         case START:
 371                 if (matches(key, value)) {
 372                         store.offset[store.seen] = ftell(config_file);
 373                         store.state = KEY_SEEN;
 374                         store.seen++;
 375                 } else {
 376                         if (strrchr(key, '.') - key == store.baselen &&
 377                               !strncmp(key, store.key, store.baselen)) {
 378                                         store.state = SECTION_SEEN;
 379                                         store.offset[store.seen] = ftell(config_file);
 380                         }
 381                 }
 382         }
 383         return 0;
 384 }
 385
 386 static void store_write_section(int fd, const char* key)
 387 {
 388         const char *dot = strchr(key, '.');
 389         int len1 = store.baselen, len2 = -1;
 390
 391         dot = strchr(key, '.');
 392         if (dot) {
 393                 int dotlen = dot - key;
 394                 if (dotlen < len1) {
 395                         len2 = len1 - dotlen - 1;
 396                         len1 = dotlen;
 397                 }
 398         }
 399
 400         write(fd, "[", 1);
 401         write(fd, key, len1);
 402         if (len2 >= 0) {
 403                 write(fd, " \"", 2);
 404                 while (--len2 >= 0) {
 405                         unsigned char c = *++dot;
 406                         if (c == '"')
 407                                 write(fd, "\\", 1);
 408                         write(fd, &c, 1);
 409                 }
 410                 write(fd, "\"", 1);
 411         }
 412         write(fd, "]\n", 2);
 413 }
 414
 415 static void store_write_pair(int fd, const char* key, const char* value)
 416 {
 417         int i;
 418
 419         write(fd, "\t", 1);
 420         write(fd, key+store.baselen+1,
 421                 strlen(key+store.baselen+1));
 422         write(fd, " = ", 3);
 423         for (i = 0; value[i]; i++)
 424                 switch (value[i]) {
 425                 case '\n': write(fd, "\\n", 2); break;
 426                 case '\t': write(fd, "\\t", 2); break;
 427                 case '"': case '\\': write(fd, "\\", 1);
 428                 default: write(fd, value+i, 1);
 429         }
 430         write(fd, "\n", 1);
 431 }
 432
 433 static int find_beginning_of_line(const char* contents, int size,
 434         int offset_, int* found_bracket)
 435 {
 436         int equal_offset = size, bracket_offset = size;
 437         int offset;
 438
 439         for (offset = offset_-2; offset > 0
 440                         && contents[offset] != '\n'; offset--)
 441                 switch (contents[offset]) {
 442                         case '=': equal_offset = offset; break;
 443                         case ']': bracket_offset = offset; break;
 444                 }
 445         if (bracket_offset < equal_offset) {
 446                 *found_bracket = 1;
 447                 offset = bracket_offset+1;
 448         } else
 449                 offset++;
 450
 451         return offset;
 452 }
 453
 454 int git_config_set(const char* key, const char* value)
 455 {
 456         return git_config_set_multivar(key, value, NULL, 0);
 457 }
 458
 459 /*
 460  * If value==NULL, unset in (remove from) config,
 461  * if value_regex!=NULL, disregard key/value pairs where value does not match.
 462  * if multi_replace==0, nothing, or only one matching key/value is replaced,
 463  *     else all matching key/values (regardless how many) are removed,
 464  *     before the new pair is written.
 465  *
 466  * Returns 0 on success.
 467  *
 468  * This function does this:
 469  *
 470  * - it locks the config file by creating ".git/config.lock"
 471  *
 472  * - it then parses the config using store_aux() as validator to find
 473  *   the position on the key/value pair to replace. If it is to be unset,
 474  *   it must be found exactly once.
 475  *
 476  * - the config file is mmap()ed and the part before the match (if any) is
 477  *   written to the lock file, then the changed part and the rest.
 478  *
 479  * - the config file is removed and the lock file rename()d to it.
 480  *
 481  */
 482 int git_config_set_multivar(const char* key, const char* value,
 483         const char* value_regex, int multi_replace)
 484 {
 485         int i, dot;
 486         int fd = -1, in_fd;
 487         int ret;
 488         char* config_filename = strdup(git_path("config"));
 489         char* lock_file = strdup(git_path("config.lock"));
 490         const char* last_dot = strrchr(key, '.');
 491
 492         /*
 493          * Since "key" actually contains the section name and the real
 494          * key name separated by a dot, we have to know where the dot is.
 495          */
 496
 497         if (last_dot == NULL) {
 498                 fprintf(stderr, "key does not contain a section: %s\n", key);
 499                 ret = 2;
 500                 goto out_free;
 501         }
 502         store.baselen = last_dot - key;
 503
 504         store.multi_replace = multi_replace;
 505
 506         /*
 507          * Validate the key and while at it, lower case it for matching.
 508          */
 509         store.key = (char*)malloc(strlen(key)+1);
 510         dot = 0;
 511         for (i = 0; key[i]; i++) {
 512                 unsigned char c = key[i];
 513                 if (c == '.')
 514                         dot = 1;
 515                 /* Leave the extended basename untouched.. */
 516                 if (!dot || i > store.baselen) {
 517                         if (!isalnum(c) || (i == store.baselen+1 && !isalpha(c))) {
 518                                 fprintf(stderr, "invalid key: %s\n", key);
 519                                 free(store.key);
 520                                 ret = 1;
 521                                 goto out_free;
 522                         }
 523                         c = tolower(c);
 524                 }
 525                 store.key[i] = c;
 526         }
 527         store.key[i] = 0;
 528
 529         /*
 530          * The lock_file serves a purpose in addition to locking: the new
 531          * contents of .git/config will be written into it.
 532          */
 533         fd = open(lock_file, O_WRONLY | O_CREAT | O_EXCL, 0666);
 534         if (fd < 0) {
 535                 fprintf(stderr, "could not lock config file\n");
 536                 free(store.key);
 537                 ret = -1;
 538                 goto out_free;
 539         }
 540
 541         /*
 542          * If .git/config does not exist yet, write a minimal version.
 543          */
 544         in_fd = open(config_filename, O_RDONLY);
 545         if ( in_fd < 0 ) {
 546                 free(store.key);
 547
 548                 if ( ENOENT != errno ) {
 549                         error("opening %s: %s", config_filename,
 550                               strerror(errno));
 551                         ret = 3; /* same as "invalid config file" */
 552                         goto out_free;
 553                 }
 554                 /* if nothing to unset, error out */
 555                 if (value == NULL) {
 556                         ret = 5;
 557                         goto out_free;
 558                 }
 559
 560                 store.key = (char*)key;
 561                 store_write_section(fd, key);
 562                 store_write_pair(fd, key, value);
 563         } else{
 564                 struct stat st;
 565                 char* contents;
 566                 int i, copy_begin, copy_end, new_line = 0;
 567
 568                 if (value_regex == NULL)
 569                         store.value_regex = NULL;
 570                 else {
 571                         if (value_regex[0] == '!') {
 572                                 store.do_not_match = 1;
 573                                 value_regex++;
 574                         } else
 575                                 store.do_not_match = 0;
 576
 577                         store.value_regex = (regex_t*)malloc(sizeof(regex_t));
 578                         if (regcomp(store.value_regex, value_regex,
 579                                         REG_EXTENDED)) {
 580                                 fprintf(stderr, "Invalid pattern: %s\n",
 581                                         value_regex);
 582                                 free(store.value_regex);
 583                                 ret = 6;
 584                                 goto out_free;
 585                         }
 586                 }
 587
 588                 store.offset[0] = 0;
 589                 store.state = START;
 590                 store.seen = 0;
 591
 592                 /*
 593                  * After this, store.offset will contain the *end* offset
 594                  * of the last match, or remain at 0 if no match was found.
 595                  * As a side effect, we make sure to transform only a valid
 596                  * existing config file.
 597                  */
 598                 if (git_config(store_aux)) {
 599                         fprintf(stderr, "invalid config file\n");
 600                         free(store.key);
 601                         if (store.value_regex != NULL) {
 602                                 regfree(store.value_regex);
 603                                 free(store.value_regex);
 604                         }
 605                         ret = 3;
 606                         goto out_free;
 607                 }
 608
 609                 free(store.key);
 610                 if (store.value_regex != NULL) {
 611                         regfree(store.value_regex);
 612                         free(store.value_regex);
 613                 }
 614
 615                 /* if nothing to unset, or too many matches, error out */
 616                 if ((store.seen == 0 && value == NULL) ||
 617                                 (store.seen > 1 && multi_replace == 0)) {
 618                         ret = 5;
 619                         goto out_free;
 620                 }
 621
 622                 fstat(in_fd, &st);
 623                 contents = mmap(NULL, st.st_size, PROT_READ,
 624                         MAP_PRIVATE, in_fd, 0);
 625                 close(in_fd);
 626
 627                 if (store.seen == 0)
 628                         store.seen = 1;
 629
 630                 for (i = 0, copy_begin = 0; i < store.seen; i++) {
 631                         if (store.offset[i] == 0) {
 632                                 store.offset[i] = copy_end = st.st_size;
 633                         } else if (store.state != KEY_SEEN) {
 634                                 copy_end = store.offset[i];
 635                         } else
 636                                 copy_end = find_beginning_of_line(
 637                                         contents, st.st_size,
 638                                         store.offset[i]-2, &new_line);
 639
 640                         /* write the first part of the config */
 641                         if (copy_end > copy_begin) {
 642                                 write(fd, contents + copy_begin,
 643                                 copy_end - copy_begin);
 644                                 if (new_line)
 645                                         write(fd, "\n", 1);
 646                         }
 647                         copy_begin = store.offset[i];
 648                 }
 649
 650                 /* write the pair (value == NULL means unset) */
 651                 if (value != NULL) {
 652                         if (store.state == START)
 653                                 store_write_section(fd, key);
 654                         store_write_pair(fd, key, value);
 655                 }
 656
 657                 /* write the rest of the config */
 658                 if (copy_begin < st.st_size)
 659                         write(fd, contents + copy_begin,
 660                                 st.st_size - copy_begin);
 661
 662                 munmap(contents, st.st_size);
 663                 unlink(config_filename);
 664         }
 665
 666         if (rename(lock_file, config_filename) < 0) {
 667                 fprintf(stderr, "Could not rename the lock file?\n");
 668                 ret = 4;
 669                 goto out_free;
 670         }
 671
 672         ret = 0;
 673
 674 out_free:
 675         if (0 <= fd)
 676                 close(fd);
 677         if (config_filename)
 678                 free(config_filename);
 679         if (lock_file) {
 680                 unlink(lock_file);
 681                 free(lock_file);
 682         }
 683         return ret;
 684 }
 685
 686