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 int config_linenr;
  15 static int get_next_char(void)
  16 {
  17         int c;
  18         FILE *f;
  19
  20         c = '\n';
  21         if ((f = config_file) != NULL) {
  22                 c = fgetc(f);
  23                 if (c == '\r') {
  24                         /* DOS like systems */
  25                         c = fgetc(f);
  26                         if (c != '\n') {
  27                                 ungetc(c, f);
  28                                 c = '\r';
  29                         }
  30                 }
  31                 if (c == '\n')
  32                         config_linenr++;
  33                 if (c == EOF) {
  34                         config_file = NULL;
  35                         c = '\n';
  36                 }
  37         }
  38         return c;
  39 }
  40
  41 static char *parse_value(void)
  42 {
  43         static char value[1024];
  44         int quote = 0, comment = 0, len = 0, space = 0;
  45
  46         for (;;) {
  47                 int c = get_next_char();
  48                 if (len >= sizeof(value))
  49                         return NULL;
  50                 if (c == '\n') {
  51                         if (quote)
  52                                 return NULL;
  53                         value[len] = 0;
  54                         return value;
  55                 }
  56                 if (comment)
  57                         continue;
  58                 if (isspace(c) && !quote) {
  59                         space = 1;
  60                         continue;
  61                 }
  62                 if (space) {
  63                         if (len)
  64                                 value[len++] = ' ';
  65                         space = 0;
  66                 }
  67                 if (c == '\\') {
  68                         c = get_next_char();
  69                         switch (c) {
  70                         case '\n':
  71                                 continue;
  72                         case 't':
  73                                 c = '\t';
  74                                 break;
  75                         case 'b':
  76                                 c = '\b';
  77                                 break;
  78                         case 'n':
  79                                 c = '\n';
  80                                 break;
  81                         /* Some characters escape as themselves */
  82                         case '\\': case '"':
  83                                 break;
  84                         /* Reject unknown escape sequences */
  85                         default:
  86                                 return NULL;
  87                         }
  88                         value[len++] = c;
  89                         continue;
  90                 }
  91                 if (c == '"') {
  92                         quote = 1-quote;
  93                         continue;
  94                 }
  95                 if (!quote) {
  96                         if (c == ';' || c == '#') {
  97                                 comment = 1;
  98                                 continue;
  99                         }
 100                 }
 101                 value[len++] = c;
 102         }
 103 }
 104
 105 static int get_value(config_fn_t fn, char *name, unsigned int len)
 106 {
 107         int c;
 108         char *value;
 109
 110         /* Get the full name */
 111         for (;;) {
 112                 c = get_next_char();
 113                 if (c == EOF)
 114                         break;
 115                 if (!isalnum(c))
 116                         break;
 117                 name[len++] = tolower(c);
 118                 if (len >= MAXNAME)
 119                         return -1;
 120         }
 121         name[len] = 0;
 122         while (c == ' ' || c == '\t')
 123                 c = get_next_char();
 124
 125         value = NULL;
 126         if (c != '\n') {
 127                 if (c != '=')
 128                         return -1;
 129                 value = parse_value();
 130                 if (!value)
 131                         return -1;
 132         }
 133         return fn(name, value);
 134 }
 135
 136 static int get_base_var(char *name)
 137 {
 138         int baselen = 0;
 139
 140         for (;;) {
 141                 int c = get_next_char();
 142                 if (c == EOF)
 143                         return -1;
 144                 if (c == ']')
 145                         return baselen;
 146                 if (!isalnum(c))
 147                         return -1;
 148                 if (baselen > MAXNAME / 2)
 149                         return -1;
 150                 name[baselen++] = tolower(c);
 151         }
 152 }
 153
 154 static int git_parse_file(config_fn_t fn)
 155 {
 156         int comment = 0;
 157         int baselen = 0;
 158         static char var[MAXNAME];
 159
 160         for (;;) {
 161                 int c = get_next_char();
 162                 if (c == '\n') {
 163                         /* EOF? */
 164                         if (!config_file)
 165                                 return 0;
 166                         comment = 0;
 167                         continue;
 168                 }
 169                 if (comment || isspace(c))
 170                         continue;
 171                 if (c == '#' || c == ';') {
 172                         comment = 1;
 173                         continue;
 174                 }
 175                 if (c == '[') {
 176                         baselen = get_base_var(var);
 177                         if (baselen <= 0)
 178                                 break;
 179                         var[baselen++] = '.';
 180                         var[baselen] = 0;
 181                         continue;
 182                 }
 183                 if (!isalpha(c))
 184                         break;
 185                 var[baselen] = tolower(c);
 186                 if (get_value(fn, var, baselen+1) < 0)
 187                         break;
 188         }
 189         die("bad config file line %d", config_linenr);
 190 }
 191
 192 int git_config_int(const char *name, const char *value)
 193 {
 194         if (value && *value) {
 195                 char *end;
 196                 int val = strtol(value, &end, 0);
 197                 if (!*end)
 198                         return val;
 199         }
 200         die("bad config value for '%s'", name);
 201 }
 202
 203 int git_config_bool(const char *name, const char *value)
 204 {
 205         if (!value)
 206                 return 1;
 207         if (!*value)
 208                 return 0;
 209         if (!strcasecmp(value, "true"))
 210                 return 1;
 211         if (!strcasecmp(value, "false"))
 212                 return 0;
 213         return git_config_int(name, value) != 0;
 214 }
 215
 216 int git_default_config(const char *var, const char *value)
 217 {
 218         /* This needs a better name */
 219         if (!strcmp(var, "core.filemode")) {
 220                 trust_executable_bit = git_config_bool(var, value);
 221                 return 0;
 222         }
 223
 224         if (!strcmp(var, "core.symrefsonly")) {
 225                 only_use_symrefs = git_config_bool(var, value);
 226                 return 0;
 227         }
 228
 229         if (!strcmp(var, "user.name")) {
 230                 strncpy(git_default_name, value, sizeof(git_default_name));
 231                 return 0;
 232         }
 233
 234         if (!strcmp(var, "user.email")) {
 235                 strncpy(git_default_email, value, sizeof(git_default_email));
 236                 return 0;
 237         }
 238
 239         if (!strcmp(var, "diff.renamelimit")) {
 240                 diff_rename_limit_default = git_config_int(var, value);
 241                 return 0;
 242         }
 243
 244         /* Add other config variables here.. */
 245         return 0;
 246 }
 247
 248 int git_config(config_fn_t fn)
 249 {
 250         int ret;
 251         FILE *f = fopen(git_path("config"), "r");
 252
 253         ret = -1;
 254         if (f) {
 255                 config_file = f;
 256                 config_linenr = 1;
 257                 ret = git_parse_file(fn);
 258                 fclose(f);
 259         }
 260         return ret;
 261 }
 262
 263 /*
 264  * Find all the stuff for git_config_set() below.
 265  */
 266
 267 #define MAX_MATCHES 512
 268
 269 static struct {
 270         int baselen;
 271         char* key;
 272         int do_not_match;
 273         regex_t* value_regex;
 274         int multi_replace;
 275         off_t offset[MAX_MATCHES];
 276         enum { START, SECTION_SEEN, SECTION_END_SEEN, KEY_SEEN } state;
 277         int seen;
 278 } store;
 279
 280 static int matches(const char* key, const char* value)
 281 {
 282         return !strcmp(key, store.key) &&
 283                 (store.value_regex == NULL ||
 284                  (store.do_not_match ^
 285                   !regexec(store.value_regex, value, 0, NULL, 0)));
 286 }
 287
 288 static int store_aux(const char* key, const char* value)
 289 {
 290         switch (store.state) {
 291         case KEY_SEEN:
 292                 if (matches(key, value)) {
 293                         if (store.seen == 1 && store.multi_replace == 0) {
 294                                 fprintf(stderr,
 295                                         "Warning: %s has multiple values\n",
 296                                         key);
 297                         } else if (store.seen >= MAX_MATCHES) {
 298                                 fprintf(stderr, "Too many matches\n");
 299                                 return 1;
 300                         }
 301
 302                         store.offset[store.seen] = ftell(config_file);
 303                         store.seen++;
 304                 }
 305                 break;
 306         case SECTION_SEEN:
 307                 if (strncmp(key, store.key, store.baselen+1)) {
 308                         store.state = SECTION_END_SEEN;
 309                         break;
 310                 } else
 311                         /* do not increment matches: this is no match */
 312                         store.offset[store.seen] = ftell(config_file);
 313                 /* fallthru */
 314         case SECTION_END_SEEN:
 315         case START:
 316                 if (matches(key, value)) {
 317                         store.offset[store.seen] = ftell(config_file);
 318                         store.state = KEY_SEEN;
 319                         store.seen++;
 320                 } else if(!strncmp(key, store.key, store.baselen))
 321                         store.state = SECTION_SEEN;
 322         }
 323         return 0;
 324 }
 325
 326 static void store_write_section(int fd, const char* key)
 327 {
 328         write(fd, "[", 1);
 329         write(fd, key, store.baselen);
 330         write(fd, "]\n", 2);
 331 }
 332
 333 static void store_write_pair(int fd, const char* key, const char* value)
 334 {
 335         int i;
 336
 337         write(fd, "\t", 1);
 338         write(fd, key+store.baselen+1,
 339                 strlen(key+store.baselen+1));
 340         write(fd, " = ", 3);
 341         for (i = 0; value[i]; i++)
 342                 switch (value[i]) {
 343                 case '\n': write(fd, "\\n", 2); break;
 344                 case '\t': write(fd, "\\t", 2); break;
 345                 case '"': case '\\': write(fd, "\\", 1);
 346                 default: write(fd, value+i, 1);
 347         }
 348         write(fd, "\n", 1);
 349 }
 350
 351 static int find_beginning_of_line(const char* contents, int size,
 352         int offset_, int* found_bracket)
 353 {
 354         int equal_offset = size, bracket_offset = size;
 355         int offset;
 356
 357         for (offset = offset_-2; offset > 0
 358                         && contents[offset] != '\n'; offset--)
 359                 switch (contents[offset]) {
 360                         case '=': equal_offset = offset; break;
 361                         case ']': bracket_offset = offset; break;
 362                 }
 363         if (bracket_offset < equal_offset) {
 364                 *found_bracket = 1;
 365                 offset = bracket_offset+1;
 366         } else
 367                 offset++;
 368
 369         return offset;
 370 }
 371
 372 int git_config_set(const char* key, const char* value)
 373 {
 374         return git_config_set_multivar(key, value, NULL, 0);
 375 }
 376
 377 /*
 378  * If value==NULL, unset in (remove from) config,
 379  * if value_regex!=NULL, disregard key/value pairs where value does not match.
 380  * if multi_replace==0, nothing, or only one matching key/value is replaced,
 381  *     else all matching key/values (regardless how many) are removed,
 382  *     before the new pair is written.
 383  *
 384  * Returns 0 on success.
 385  *
 386  * This function does this:
 387  *
 388  * - it locks the config file by creating ".git/config.lock"
 389  *
 390  * - it then parses the config using store_aux() as validator to find
 391  *   the position on the key/value pair to replace. If it is to be unset,
 392  *   it must be found exactly once.
 393  *
 394  * - the config file is mmap()ed and the part before the match (if any) is
 395  *   written to the lock file, then the changed part and the rest.
 396  *
 397  * - the config file is removed and the lock file rename()d to it.
 398  *
 399  */
 400 int git_config_set_multivar(const char* key, const char* value,
 401         const char* value_regex, int multi_replace)
 402 {
 403         int i;
 404         struct stat st;
 405         int fd;
 406         char* config_file = strdup(git_path("config"));
 407         char* lock_file = strdup(git_path("config.lock"));
 408
 409         store.multi_replace = multi_replace;
 410
 411         /*
 412          * Since "key" actually contains the section name and the real
 413          * key name separated by a dot, we have to know where the dot is.
 414          */
 415         for (store.baselen = 0;
 416                         key[store.baselen] != '.' && key[store.baselen];
 417                         store.baselen++);
 418         if (!key[store.baselen] || !key[store.baselen+1]) {
 419                 fprintf(stderr, "key does not contain a section: %s\n", key);
 420                 return 2;
 421         }
 422
 423         /*
 424          * Validate the key and while at it, lower case it for matching.
 425          */
 426         store.key = (char*)malloc(strlen(key)+1);
 427         for (i = 0; key[i]; i++)
 428                 if (i != store.baselen && (!isalnum(key[i]) ||
 429                                 (i == store.baselen+1 && !isalpha(key[i])))) {
 430                         fprintf(stderr, "invalid key: %s\n", key);
 431                         free(store.key);
 432                         return 1;
 433                 } else
 434                         store.key[i] = tolower(key[i]);
 435
 436         /*
 437          * The lock_file serves a purpose in addition to locking: the new
 438          * contents of .git/config will be written into it.
 439          */
 440         fd = open(lock_file, O_WRONLY | O_CREAT | O_EXCL, 0666);
 441         if (fd < 0) {
 442                 fprintf(stderr, "could not lock config file\n");
 443                 free(store.key);
 444                 return -1;
 445         }
 446
 447         /*
 448          * If .git/config does not exist yet, write a minimal version.
 449          */
 450         if (stat(config_file, &st)) {
 451                 static const char contents[] =
 452                         "#\n"
 453                         "# This is the config file\n"
 454                         "#\n"
 455                         "\n";
 456
 457                 free(store.key);
 458
 459                 /* if nothing to unset, error out */
 460                 if (value == NULL) {
 461                         close(fd);
 462                         unlink(lock_file);
 463                         return 5;
 464                 }
 465
 466                 store.key = (char*)key;
 467
 468                 write(fd, contents, sizeof(contents)-1);
 469                 store_write_section(fd, key);
 470                 store_write_pair(fd, key, value);
 471         } else{
 472                 int in_fd;
 473                 char* contents;
 474                 int i, copy_begin, copy_end, new_line = 0;
 475
 476                 if (value_regex == NULL)
 477                         store.value_regex = NULL;
 478                 else {
 479                         if (value_regex[0] == '!') {
 480                                 store.do_not_match = 1;
 481                                 value_regex++;
 482                         } else
 483                                 store.do_not_match = 0;
 484
 485                         store.value_regex = (regex_t*)malloc(sizeof(regex_t));
 486                         if (regcomp(store.value_regex, value_regex,
 487                                         REG_EXTENDED)) {
 488                                 fprintf(stderr, "Invalid pattern: %s",
 489                                         value_regex);
 490                                 free(store.value_regex);
 491                                 return 6;
 492                         }
 493                 }
 494
 495                 store.offset[0] = 0;
 496                 store.state = START;
 497                 store.seen = 0;
 498
 499                 /*
 500                  * After this, store.offset will contain the *end* offset
 501                  * of the last match, or remain at 0 if no match was found.
 502                  * As a side effect, we make sure to transform only a valid
 503                  * existing config file.
 504                  */
 505                 if (git_config(store_aux)) {
 506                         fprintf(stderr, "invalid config file\n");
 507                         free(store.key);
 508                         if (store.value_regex != NULL) {
 509                                 regfree(store.value_regex);
 510                                 free(store.value_regex);
 511                         }
 512                         return 3;
 513                 }
 514
 515                 free(store.key);
 516                 if (store.value_regex != NULL) {
 517                         regfree(store.value_regex);
 518                         free(store.value_regex);
 519                 }
 520
 521                 /* if nothing to unset, or too many matches, error out */
 522                 if ((store.seen == 0 && value == NULL) ||
 523                                 (store.seen > 1 && multi_replace == 0)) {
 524                         close(fd);
 525                         unlink(lock_file);
 526                         return 5;
 527                 }
 528
 529                 in_fd = open(config_file, O_RDONLY, 0666);
 530                 contents = mmap(NULL, st.st_size, PROT_READ,
 531                         MAP_PRIVATE, in_fd, 0);
 532                 close(in_fd);
 533
 534                 if (store.seen == 0)
 535                         store.seen = 1;
 536
 537                 for (i = 0, copy_begin = 0; i < store.seen; i++) {
 538                         if (store.offset[i] == 0) {
 539                                 store.offset[i] = copy_end = st.st_size;
 540                         } else if (store.state != KEY_SEEN) {
 541                                 copy_end = store.offset[i];
 542                         } else
 543                                 copy_end = find_beginning_of_line(
 544                                         contents, st.st_size,
 545                                         store.offset[i]-2, &new_line);
 546
 547                         /* write the first part of the config */
 548                         if (copy_end > copy_begin) {
 549                                 write(fd, contents + copy_begin,
 550                                 copy_end - copy_begin);
 551                                 if (new_line)
 552                                         write(fd, "\n", 1);
 553                         }
 554                         copy_begin = store.offset[i];
 555                 }
 556
 557                 /* write the pair (value == NULL means unset) */
 558                 if (value != NULL) {
 559                         if (store.state == START)
 560                                 store_write_section(fd, key);
 561                         store_write_pair(fd, key, value);
 562                 }
 563
 564                 /* write the rest of the config */
 565                 if (copy_begin < st.st_size)
 566                         write(fd, contents + copy_begin,
 567                                 st.st_size - copy_begin);
 568
 569                 munmap(contents, st.st_size);
 570                 unlink(config_file);
 571         }
 572
 573         close(fd);
 574
 575         if (rename(lock_file, config_file) < 0) {
 576                 fprintf(stderr, "Could not rename the lock file?\n");
 577                 return 4;
 578         }
 579
 580         return 0;
 581 }
 582
 583