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_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.ignorestat")) {
 226                 assume_unchanged = git_config_bool(var, value);
 227                 return 0;
 228         }
 229
 230         if (!strcmp(var, "core.prefersymlinkrefs")) {
 231                 prefer_symlink_refs = git_config_bool(var, value);
 232                 return 0;
 233         }
 234
 235         if (!strcmp(var, "core.warnambiguousrefs")) {
 236                 warn_ambiguous_refs = git_config_bool(var, value);
 237                 return 0;
 238         }
 239
 240         if (!strcmp(var, "user.name")) {
 241                 strncpy(git_default_name, value, sizeof(git_default_name));
 242                 return 0;
 243         }
 244
 245         if (!strcmp(var, "user.email")) {
 246                 strncpy(git_default_email, value, sizeof(git_default_email));
 247                 return 0;
 248         }
 249
 250         if (!strcmp(var, "i18n.commitencoding")) {
 251                 strncpy(git_commit_encoding, value, sizeof(git_commit_encoding));
 252                 return 0;
 253         }
 254
 255         /* Add other config variables here and to Documentation/config.txt. */
 256         return 0;
 257 }
 258
 259 int git_config_from_file(config_fn_t fn, const char *filename)
 260 {
 261         int ret;
 262         FILE *f = fopen(filename, "r");
 263
 264         ret = -1;
 265         if (f) {
 266                 config_file = f;
 267                 config_file_name = filename;
 268                 config_linenr = 1;
 269                 ret = git_parse_file(fn);
 270                 fclose(f);
 271                 config_file_name = NULL;
 272         }
 273         return ret;
 274 }
 275
 276 int git_config(config_fn_t fn)
 277 {
 278         return git_config_from_file(fn, git_path("config"));
 279 }
 280
 281 /*
 282  * Find all the stuff for git_config_set() below.
 283  */
 284
 285 #define MAX_MATCHES 512
 286
 287 static struct {
 288         int baselen;
 289         char* key;
 290         int do_not_match;
 291         regex_t* value_regex;
 292         int multi_replace;
 293         off_t offset[MAX_MATCHES];
 294         enum { START, SECTION_SEEN, SECTION_END_SEEN, KEY_SEEN } state;
 295         int seen;
 296 } store;
 297
 298 static int matches(const char* key, const char* value)
 299 {
 300         return !strcmp(key, store.key) &&
 301                 (store.value_regex == NULL ||
 302                  (store.do_not_match ^
 303                   !regexec(store.value_regex, value, 0, NULL, 0)));
 304 }
 305
 306 static int store_aux(const char* key, const char* value)
 307 {
 308         switch (store.state) {
 309         case KEY_SEEN:
 310                 if (matches(key, value)) {
 311                         if (store.seen == 1 && store.multi_replace == 0) {
 312                                 fprintf(stderr,
 313                                         "Warning: %s has multiple values\n",
 314                                         key);
 315                         } else if (store.seen >= MAX_MATCHES) {
 316                                 fprintf(stderr, "Too many matches\n");
 317                                 return 1;
 318                         }
 319
 320                         store.offset[store.seen] = ftell(config_file);
 321                         store.seen++;
 322                 }
 323                 break;
 324         case SECTION_SEEN:
 325                 if (strncmp(key, store.key, store.baselen+1)) {
 326                         store.state = SECTION_END_SEEN;
 327                         break;
 328                 } else
 329                         /* do not increment matches: this is no match */
 330                         store.offset[store.seen] = ftell(config_file);
 331                 /* fallthru */
 332         case SECTION_END_SEEN:
 333         case START:
 334                 if (matches(key, value)) {
 335                         store.offset[store.seen] = ftell(config_file);
 336                         store.state = KEY_SEEN;
 337                         store.seen++;
 338                 } else if (strrchr(key, '.') - key == store.baselen &&
 339                               !strncmp(key, store.key, store.baselen)) {
 340                                         store.state = SECTION_SEEN;
 341                                         store.offset[store.seen] = ftell(config_file);
 342                 }
 343         }
 344         return 0;
 345 }
 346
 347 static void store_write_section(int fd, const char* key)
 348 {
 349         write(fd, "[", 1);
 350         write(fd, key, store.baselen);
 351         write(fd, "]\n", 2);
 352 }
 353
 354 static void store_write_pair(int fd, const char* key, const char* value)
 355 {
 356         int i;
 357
 358         write(fd, "\t", 1);
 359         write(fd, key+store.baselen+1,
 360                 strlen(key+store.baselen+1));
 361         write(fd, " = ", 3);
 362         for (i = 0; value[i]; i++)
 363                 switch (value[i]) {
 364                 case '\n': write(fd, "\\n", 2); break;
 365                 case '\t': write(fd, "\\t", 2); break;
 366                 case '"': case '\\': write(fd, "\\", 1);
 367                 default: write(fd, value+i, 1);
 368         }
 369         write(fd, "\n", 1);
 370 }
 371
 372 static int find_beginning_of_line(const char* contents, int size,
 373         int offset_, int* found_bracket)
 374 {
 375         int equal_offset = size, bracket_offset = size;
 376         int offset;
 377
 378         for (offset = offset_-2; offset > 0
 379                         && contents[offset] != '\n'; offset--)
 380                 switch (contents[offset]) {
 381                         case '=': equal_offset = offset; break;
 382                         case ']': bracket_offset = offset; break;
 383                 }
 384         if (bracket_offset < equal_offset) {
 385                 *found_bracket = 1;
 386                 offset = bracket_offset+1;
 387         } else
 388                 offset++;
 389
 390         return offset;
 391 }
 392
 393 int git_config_set(const char* key, const char* value)
 394 {
 395         return git_config_set_multivar(key, value, NULL, 0);
 396 }
 397
 398 /*
 399  * If value==NULL, unset in (remove from) config,
 400  * if value_regex!=NULL, disregard key/value pairs where value does not match.
 401  * if multi_replace==0, nothing, or only one matching key/value is replaced,
 402  *     else all matching key/values (regardless how many) are removed,
 403  *     before the new pair is written.
 404  *
 405  * Returns 0 on success.
 406  *
 407  * This function does this:
 408  *
 409  * - it locks the config file by creating ".git/config.lock"
 410  *
 411  * - it then parses the config using store_aux() as validator to find
 412  *   the position on the key/value pair to replace. If it is to be unset,
 413  *   it must be found exactly once.
 414  *
 415  * - the config file is mmap()ed and the part before the match (if any) is
 416  *   written to the lock file, then the changed part and the rest.
 417  *
 418  * - the config file is removed and the lock file rename()d to it.
 419  *
 420  */
 421 int git_config_set_multivar(const char* key, const char* value,
 422         const char* value_regex, int multi_replace)
 423 {
 424         int i;
 425         int fd, in_fd;
 426         int ret;
 427         char* config_filename = strdup(git_path("config"));
 428         char* lock_file = strdup(git_path("config.lock"));
 429         const char* last_dot = strrchr(key, '.');
 430
 431         /*
 432          * Since "key" actually contains the section name and the real
 433          * key name separated by a dot, we have to know where the dot is.
 434          */
 435
 436         if (last_dot == NULL) {
 437                 fprintf(stderr, "key does not contain a section: %s\n", key);
 438                 ret = 2;
 439                 goto out_free;
 440         }
 441         store.baselen = last_dot - key;
 442
 443         store.multi_replace = multi_replace;
 444
 445         /*
 446          * Validate the key and while at it, lower case it for matching.
 447          */
 448         store.key = (char*)malloc(strlen(key)+1);
 449         for (i = 0; key[i]; i++)
 450                 if (i != store.baselen &&
 451                                 ((!isalnum(key[i]) && key[i] != '.') ||
 452                                  (i == store.baselen+1 && !isalpha(key[i])))) {
 453                         fprintf(stderr, "invalid key: %s\n", key);
 454                         free(store.key);
 455                         ret = 1;
 456                         goto out_free;
 457                 } else
 458                         store.key[i] = tolower(key[i]);
 459         store.key[i] = 0;
 460
 461         /*
 462          * The lock_file serves a purpose in addition to locking: the new
 463          * contents of .git/config will be written into it.
 464          */
 465         fd = open(lock_file, O_WRONLY | O_CREAT | O_EXCL, 0666);
 466         if (fd < 0) {
 467                 fprintf(stderr, "could not lock config file\n");
 468                 free(store.key);
 469                 ret = -1;
 470                 goto out_free;
 471         }
 472
 473         /*
 474          * If .git/config does not exist yet, write a minimal version.
 475          */
 476         in_fd = open(config_filename, O_RDONLY);
 477         if ( in_fd < 0 ) {
 478                 free(store.key);
 479
 480                 if ( ENOENT != errno ) {
 481                         error("opening %s: %s", config_filename,
 482                               strerror(errno));
 483                         close(fd);
 484                         unlink(lock_file);
 485                         ret = 3; /* same as "invalid config file" */
 486                         goto out_free;
 487                 }
 488                 /* if nothing to unset, error out */
 489                 if (value == NULL) {
 490                         close(fd);
 491                         unlink(lock_file);
 492                         ret = 5;
 493                         goto out_free;
 494                 }
 495
 496                 store.key = (char*)key;
 497                 store_write_section(fd, key);
 498                 store_write_pair(fd, key, value);
 499         } else{
 500                 struct stat st;
 501                 char* contents;
 502                 int i, copy_begin, copy_end, new_line = 0;
 503
 504                 if (value_regex == NULL)
 505                         store.value_regex = NULL;
 506                 else {
 507                         if (value_regex[0] == '!') {
 508                                 store.do_not_match = 1;
 509                                 value_regex++;
 510                         } else
 511                                 store.do_not_match = 0;
 512
 513                         store.value_regex = (regex_t*)malloc(sizeof(regex_t));
 514                         if (regcomp(store.value_regex, value_regex,
 515                                         REG_EXTENDED)) {
 516                                 fprintf(stderr, "Invalid pattern: %s\n",
 517                                         value_regex);
 518                                 free(store.value_regex);
 519                                 close(fd);
 520                                 unlink(lock_file);
 521                                 ret = 6;
 522                                 goto out_free;
 523                         }
 524                 }
 525
 526                 store.offset[0] = 0;
 527                 store.state = START;
 528                 store.seen = 0;
 529
 530                 /*
 531                  * After this, store.offset will contain the *end* offset
 532                  * of the last match, or remain at 0 if no match was found.
 533                  * As a side effect, we make sure to transform only a valid
 534                  * existing config file.
 535                  */
 536                 if (git_config(store_aux)) {
 537                         fprintf(stderr, "invalid config file\n");
 538                         free(store.key);
 539                         if (store.value_regex != NULL) {
 540                                 regfree(store.value_regex);
 541                                 free(store.value_regex);
 542                         }
 543                         ret = 3;
 544                         goto out_free;
 545                 }
 546
 547                 free(store.key);
 548                 if (store.value_regex != NULL) {
 549                         regfree(store.value_regex);
 550                         free(store.value_regex);
 551                 }
 552
 553                 /* if nothing to unset, or too many matches, error out */
 554                 if ((store.seen == 0 && value == NULL) ||
 555                                 (store.seen > 1 && multi_replace == 0)) {
 556                         close(fd);
 557                         unlink(lock_file);
 558                         ret = 5;
 559                         goto out_free;
 560                 }
 561
 562                 fstat(in_fd, &st);
 563                 contents = mmap(NULL, st.st_size, PROT_READ,
 564                         MAP_PRIVATE, in_fd, 0);
 565                 close(in_fd);
 566
 567                 if (store.seen == 0)
 568                         store.seen = 1;
 569
 570                 for (i = 0, copy_begin = 0; i < store.seen; i++) {
 571                         if (store.offset[i] == 0) {
 572                                 store.offset[i] = copy_end = st.st_size;
 573                         } else if (store.state != KEY_SEEN) {
 574                                 copy_end = store.offset[i];
 575                         } else
 576                                 copy_end = find_beginning_of_line(
 577                                         contents, st.st_size,
 578                                         store.offset[i]-2, &new_line);
 579
 580                         /* write the first part of the config */
 581                         if (copy_end > copy_begin) {
 582                                 write(fd, contents + copy_begin,
 583                                 copy_end - copy_begin);
 584                                 if (new_line)
 585                                         write(fd, "\n", 1);
 586                         }
 587                         copy_begin = store.offset[i];
 588                 }
 589
 590                 /* write the pair (value == NULL means unset) */
 591                 if (value != NULL) {
 592                         if (store.state == START)
 593                                 store_write_section(fd, key);
 594                         store_write_pair(fd, key, value);
 595                 }
 596
 597                 /* write the rest of the config */
 598                 if (copy_begin < st.st_size)
 599                         write(fd, contents + copy_begin,
 600                                 st.st_size - copy_begin);
 601
 602                 munmap(contents, st.st_size);
 603                 unlink(config_filename);
 604         }
 605
 606         close(fd);
 607
 608         if (rename(lock_file, config_filename) < 0) {
 609                 fprintf(stderr, "Could not rename the lock file?\n");
 610                 ret = 4;
 611                 goto out_free;
 612         }
 613
 614         ret = 0;
 615
 616 out_free:
 617         if (config_filename)
 618                 free(config_filename);
 619         if (lock_file)
 620                 free(lock_file);
 621         return ret;
 622 }
 623
 624