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 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 (space) {
  64                         if (len)
  65                                 value[len++] = ' ';
  66                         space = 0;
  67                 }
  68                 if (c == '\\') {
  69                         c = get_next_char();
  70                         switch (c) {
  71                         case '\n':
  72                                 continue;
  73                         case 't':
  74                                 c = '\t';
  75                                 break;
  76                         case 'b':
  77                                 c = '\b';
  78                                 break;
  79                         case 'n':
  80                                 c = '\n';
  81                                 break;
  82                         /* Some characters escape as themselves */
  83                         case '\\': case '"':
  84                                 break;
  85                         /* Reject unknown escape sequences */
  86                         default:
  87                                 return NULL;
  88                         }
  89                         value[len++] = c;
  90                         continue;
  91                 }
  92                 if (c == '"') {
  93                         quote = 1-quote;
  94                         continue;
  95                 }
  96                 if (!quote) {
  97                         if (c == ';' || c == '#') {
  98                                 comment = 1;
  99                                 continue;
 100                         }
 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_base_var(char *name)
 138 {
 139         int baselen = 0;
 140
 141         for (;;) {
 142                 int c = get_next_char();
 143                 if (c == EOF)
 144                         return -1;
 145                 if (c == ']')
 146                         return baselen;
 147                 if (!isalnum(c) && c != '.')
 148                         return -1;
 149                 if (baselen > MAXNAME / 2)
 150                         return -1;
 151                 name[baselen++] = tolower(c);
 152         }
 153 }
 154
 155 static int git_parse_file(config_fn_t fn)
 156 {
 157         int comment = 0;
 158         int baselen = 0;
 159         static char var[MAXNAME];
 160
 161         for (;;) {
 162                 int c = get_next_char();
 163                 if (c == '\n') {
 164                         /* EOF? */
 165                         if (!config_file)
 166                                 return 0;
 167                         comment = 0;
 168                         continue;
 169                 }
 170                 if (comment || isspace(c))
 171                         continue;
 172                 if (c == '#' || c == ';') {
 173                         comment = 1;
 174                         continue;
 175                 }
 176                 if (c == '[') {
 177                         baselen = get_base_var(var);
 178                         if (baselen <= 0)
 179                                 break;
 180                         var[baselen++] = '.';
 181                         var[baselen] = 0;
 182                         continue;
 183                 }
 184                 if (!isalpha(c))
 185                         break;
 186                 var[baselen] = tolower(c);
 187                 if (get_value(fn, var, baselen+1) < 0)
 188                         break;
 189         }
 190         die("bad config file line %d in %s", config_linenr, config_file_name);
 191 }
 192
 193 int git_config_int(const char *name, const char *value)
 194 {
 195         if (value && *value) {
 196                 char *end;
 197                 int val = strtol(value, &end, 0);
 198                 if (!*end)
 199                         return val;
 200         }
 201         die("bad config value for '%s' in %s", name, config_file_name);
 202 }
 203
 204 int git_config_bool(const char *name, const char *value)
 205 {
 206         if (!value)
 207                 return 1;
 208         if (!*value)
 209                 return 0;
 210         if (!strcasecmp(value, "true"))
 211                 return 1;
 212         if (!strcasecmp(value, "false"))
 213                 return 0;
 214         return git_config_int(name, value) != 0;
 215 }
 216
 217 int git_default_config(const char *var, const char *value)
 218 {
 219         /* This needs a better name */
 220         if (!strcmp(var, "core.filemode")) {
 221                 trust_executable_bit = git_config_bool(var, value);
 222                 return 0;
 223         }
 224
 225         if (!strcmp(var, "core.symrefsonly")) {
 226                 only_use_symrefs = git_config_bool(var, value);
 227                 return 0;
 228         }
 229
 230         if (!strcmp(var, "user.name")) {
 231                 strncpy(git_default_name, value, sizeof(git_default_name));
 232                 return 0;
 233         }
 234
 235         if (!strcmp(var, "user.email")) {
 236                 strncpy(git_default_email, value, sizeof(git_default_email));
 237                 return 0;
 238         }
 239
 240         /* Add other config variables here.. */
 241         return 0;
 242 }
 243
 244 int git_config_from_file(config_fn_t fn, const char *filename)
 245 {
 246         int ret;
 247         FILE *f = fopen(filename, "r");
 248
 249         ret = -1;
 250         if (f) {
 251                 config_file = f;
 252                 config_file_name = filename;
 253                 config_linenr = 1;
 254                 ret = git_parse_file(fn);
 255                 fclose(f);
 256                 config_file_name = NULL;
 257         }
 258         return ret;
 259 }
 260
 261 int git_config(config_fn_t fn)
 262 {
 263         return git_config_from_file(fn, git_path("config"));
 264 }
 265
 266 /*
 267  * Find all the stuff for git_config_set() below.
 268  */
 269
 270 #define MAX_MATCHES 512
 271
 272 static struct {
 273         int baselen;
 274         char* key;
 275         int do_not_match;
 276         regex_t* value_regex;
 277         int multi_replace;
 278         off_t offset[MAX_MATCHES];
 279         enum { START, SECTION_SEEN, SECTION_END_SEEN, KEY_SEEN } state;
 280         int seen;
 281 } store;
 282
 283 static int matches(const char* key, const char* value)
 284 {
 285         return !strcmp(key, store.key) &&
 286                 (store.value_regex == NULL ||
 287                  (store.do_not_match ^
 288                   !regexec(store.value_regex, value, 0, NULL, 0)));
 289 }
 290
 291 static int store_aux(const char* key, const char* value)
 292 {
 293         switch (store.state) {
 294         case KEY_SEEN:
 295                 if (matches(key, value)) {
 296                         if (store.seen == 1 && store.multi_replace == 0) {
 297                                 fprintf(stderr,
 298                                         "Warning: %s has multiple values\n",
 299                                         key);
 300                         } else if (store.seen >= MAX_MATCHES) {
 301                                 fprintf(stderr, "Too many matches\n");
 302                                 return 1;
 303                         }
 304
 305                         store.offset[store.seen] = ftell(config_file);
 306                         store.seen++;
 307                 }
 308                 break;
 309         case SECTION_SEEN:
 310                 if (strncmp(key, store.key, store.baselen+1)) {
 311                         store.state = SECTION_END_SEEN;
 312                         break;
 313                 } else
 314                         /* do not increment matches: this is no match */
 315                         store.offset[store.seen] = ftell(config_file);
 316                 /* fallthru */
 317         case SECTION_END_SEEN:
 318         case START:
 319                 if (matches(key, value)) {
 320                         store.offset[store.seen] = ftell(config_file);
 321                         store.state = KEY_SEEN;
 322                         store.seen++;
 323                 } else if(!strncmp(key, store.key, store.baselen))
 324                         store.state = SECTION_SEEN;
 325         }
 326         return 0;
 327 }
 328
 329 static void store_write_section(int fd, const char* key)
 330 {
 331         write(fd, "[", 1);
 332         write(fd, key, store.baselen);
 333         write(fd, "]\n", 2);
 334 }
 335
 336 static void store_write_pair(int fd, const char* key, const char* value)
 337 {
 338         int i;
 339
 340         write(fd, "\t", 1);
 341         write(fd, key+store.baselen+1,
 342                 strlen(key+store.baselen+1));
 343         write(fd, " = ", 3);
 344         for (i = 0; value[i]; i++)
 345                 switch (value[i]) {
 346                 case '\n': write(fd, "\\n", 2); break;
 347                 case '\t': write(fd, "\\t", 2); break;
 348                 case '"': case '\\': write(fd, "\\", 1);
 349                 default: write(fd, value+i, 1);
 350         }
 351         write(fd, "\n", 1);
 352 }
 353
 354 static int find_beginning_of_line(const char* contents, int size,
 355         int offset_, int* found_bracket)
 356 {
 357         int equal_offset = size, bracket_offset = size;
 358         int offset;
 359
 360         for (offset = offset_-2; offset > 0
 361                         && contents[offset] != '\n'; offset--)
 362                 switch (contents[offset]) {
 363                         case '=': equal_offset = offset; break;
 364                         case ']': bracket_offset = offset; break;
 365                 }
 366         if (bracket_offset < equal_offset) {
 367                 *found_bracket = 1;
 368                 offset = bracket_offset+1;
 369         } else
 370                 offset++;
 371
 372         return offset;
 373 }
 374
 375 int git_config_set(const char* key, const char* value)
 376 {
 377         return git_config_set_multivar(key, value, NULL, 0);
 378 }
 379
 380 /*
 381  * If value==NULL, unset in (remove from) config,
 382  * if value_regex!=NULL, disregard key/value pairs where value does not match.
 383  * if multi_replace==0, nothing, or only one matching key/value is replaced,
 384  *     else all matching key/values (regardless how many) are removed,
 385  *     before the new pair is written.
 386  *
 387  * Returns 0 on success.
 388  *
 389  * This function does this:
 390  *
 391  * - it locks the config file by creating ".git/config.lock"
 392  *
 393  * - it then parses the config using store_aux() as validator to find
 394  *   the position on the key/value pair to replace. If it is to be unset,
 395  *   it must be found exactly once.
 396  *
 397  * - the config file is mmap()ed and the part before the match (if any) is
 398  *   written to the lock file, then the changed part and the rest.
 399  *
 400  * - the config file is removed and the lock file rename()d to it.
 401  *
 402  */
 403 int git_config_set_multivar(const char* key, const char* value,
 404         const char* value_regex, int multi_replace)
 405 {
 406         int i;
 407         struct stat st;
 408         int fd;
 409         char* config_filename = strdup(git_path("config"));
 410         char* lock_file = strdup(git_path("config.lock"));
 411         const char* last_dot = strrchr(key, '.');
 412
 413         /*
 414          * Since "key" actually contains the section name and the real
 415          * key name separated by a dot, we have to know where the dot is.
 416          */
 417
 418         if (last_dot == NULL) {
 419                 fprintf(stderr, "key does not contain a section: %s\n", key);
 420                 return 2;
 421         }
 422         store.baselen = last_dot - key;
 423
 424         store.multi_replace = multi_replace;
 425
 426         /*
 427          * Validate the key and while at it, lower case it for matching.
 428          */
 429         store.key = (char*)malloc(strlen(key)+1);
 430         for (i = 0; key[i]; i++)
 431                 if (i != store.baselen &&
 432                                 ((!isalnum(key[i]) && key[i] != '.') ||
 433                                  (i == store.baselen+1 && !isalpha(key[i])))) {
 434                         fprintf(stderr, "invalid key: %s\n", key);
 435                         free(store.key);
 436                         return 1;
 437                 } else
 438                         store.key[i] = tolower(key[i]);
 439         store.key[i] = 0;
 440
 441         /*
 442          * The lock_file serves a purpose in addition to locking: the new
 443          * contents of .git/config will be written into it.
 444          */
 445         fd = open(lock_file, O_WRONLY | O_CREAT | O_EXCL, 0666);
 446         if (fd < 0) {
 447                 fprintf(stderr, "could not lock config file\n");
 448                 free(store.key);
 449                 return -1;
 450         }
 451
 452         /*
 453          * If .git/config does not exist yet, write a minimal version.
 454          */
 455         if (stat(config_filename, &st)) {
 456                 static const char contents[] =
 457                         "#\n"
 458                         "# This is the config file\n"
 459                         "#\n"
 460                         "\n";
 461
 462                 free(store.key);
 463
 464                 /* if nothing to unset, error out */
 465                 if (value == NULL) {
 466                         close(fd);
 467                         unlink(lock_file);
 468                         return 5;
 469                 }
 470
 471                 store.key = (char*)key;
 472
 473                 write(fd, contents, sizeof(contents)-1);
 474                 store_write_section(fd, key);
 475                 store_write_pair(fd, key, value);
 476         } else{
 477                 int in_fd;
 478                 char* contents;
 479                 int i, copy_begin, copy_end, new_line = 0;
 480
 481                 if (value_regex == NULL)
 482                         store.value_regex = NULL;
 483                 else {
 484                         if (value_regex[0] == '!') {
 485                                 store.do_not_match = 1;
 486                                 value_regex++;
 487                         } else
 488                                 store.do_not_match = 0;
 489
 490                         store.value_regex = (regex_t*)malloc(sizeof(regex_t));
 491                         if (regcomp(store.value_regex, value_regex,
 492                                         REG_EXTENDED)) {
 493                                 fprintf(stderr, "Invalid pattern: %s",
 494                                         value_regex);
 495                                 free(store.value_regex);
 496                                 return 6;
 497                         }
 498                 }
 499
 500                 store.offset[0] = 0;
 501                 store.state = START;
 502                 store.seen = 0;
 503
 504                 /*
 505                  * After this, store.offset will contain the *end* offset
 506                  * of the last match, or remain at 0 if no match was found.
 507                  * As a side effect, we make sure to transform only a valid
 508                  * existing config file.
 509                  */
 510                 if (git_config(store_aux)) {
 511                         fprintf(stderr, "invalid config file\n");
 512                         free(store.key);
 513                         if (store.value_regex != NULL) {
 514                                 regfree(store.value_regex);
 515                                 free(store.value_regex);
 516                         }
 517                         return 3;
 518                 }
 519
 520                 free(store.key);
 521                 if (store.value_regex != NULL) {
 522                         regfree(store.value_regex);
 523                         free(store.value_regex);
 524                 }
 525
 526                 /* if nothing to unset, or too many matches, error out */
 527                 if ((store.seen == 0 && value == NULL) ||
 528                                 (store.seen > 1 && multi_replace == 0)) {
 529                         close(fd);
 530                         unlink(lock_file);
 531                         return 5;
 532                 }
 533
 534                 in_fd = open(config_filename, O_RDONLY, 0666);
 535                 contents = mmap(NULL, st.st_size, PROT_READ,
 536                         MAP_PRIVATE, in_fd, 0);
 537                 close(in_fd);
 538
 539                 if (store.seen == 0)
 540                         store.seen = 1;
 541
 542                 for (i = 0, copy_begin = 0; i < store.seen; i++) {
 543                         if (store.offset[i] == 0) {
 544                                 store.offset[i] = copy_end = st.st_size;
 545                         } else if (store.state != KEY_SEEN) {
 546                                 copy_end = store.offset[i];
 547                         } else
 548                                 copy_end = find_beginning_of_line(
 549                                         contents, st.st_size,
 550                                         store.offset[i]-2, &new_line);
 551
 552                         /* write the first part of the config */
 553                         if (copy_end > copy_begin) {
 554                                 write(fd, contents + copy_begin,
 555                                 copy_end - copy_begin);
 556                                 if (new_line)
 557                                         write(fd, "\n", 1);
 558                         }
 559                         copy_begin = store.offset[i];
 560                 }
 561
 562                 /* write the pair (value == NULL means unset) */
 563                 if (value != NULL) {
 564                         if (store.state == START)
 565                                 store_write_section(fd, key);
 566                         store_write_pair(fd, key, value);
 567                 }
 568
 569                 /* write the rest of the config */
 570                 if (copy_begin < st.st_size)
 571                         write(fd, contents + copy_begin,
 572                                 st.st_size - copy_begin);
 573
 574                 munmap(contents, st.st_size);
 575                 unlink(config_filename);
 576         }
 577
 578         close(fd);
 579
 580         if (rename(lock_file, config_filename) < 0) {
 581                 fprintf(stderr, "Could not rename the lock file?\n");
 582                 return 4;
 583         }
 584
 585         return 0;
 586 }
 587
 588