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