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 static struct {
 267         int baselen;
 268         char* key;
 269         regex_t* value_regex;
 270         off_t offset;
 271         enum { START, SECTION_SEEN, SECTION_END_SEEN, KEY_SEEN } state;
 272         int seen;
 273 } store;
 274
 275 static int store_aux(const char* key, const char* value)
 276 {
 277         switch (store.state) {
 278         case KEY_SEEN:
 279                 if (!strcmp(key, store.key) &&
 280                                 (store.value_regex == NULL ||
 281                                 !regexec(store.value_regex, value, 0, NULL, 0))) {
 282                         if (store.seen == 1) {
 283                                 fprintf(stderr,
 284                                         "Warning: %s has multiple values\n",
 285                                         key);
 286                         }
 287                         store.offset = ftell(config_file);
 288                         store.seen++;
 289                 }
 290                 break;
 291         case SECTION_SEEN:
 292                 if (strncmp(key, store.key, store.baselen+1)) {
 293                         store.state = SECTION_END_SEEN;
 294                         break;
 295                 } else
 296                         store.offset = ftell(config_file);
 297                 /* fallthru */
 298         case SECTION_END_SEEN:
 299         case START:
 300                 if (!strcmp(key, store.key) &&
 301                                 (store.value_regex == NULL ||
 302                                 !regexec(store.value_regex, value, 0, NULL, 0))) {
 303                         store.offset = ftell(config_file);
 304                         store.state = KEY_SEEN;
 305                         store.seen++;
 306                 } else if(!strncmp(key, store.key, store.baselen))
 307                         store.state = SECTION_SEEN;
 308         }
 309         return 0;
 310 }
 311
 312 static void store_write_section(int fd, const char* key)
 313 {
 314         write(fd, "[", 1);
 315         write(fd, key, store.baselen);
 316         write(fd, "]\n", 2);
 317 }
 318
 319 static void store_write_pair(int fd, const char* key, const char* value)
 320 {
 321         int i;
 322
 323         write(fd, "\t", 1);
 324         write(fd, key+store.baselen+1,
 325                 strlen(key+store.baselen+1));
 326         write(fd, " = ", 3);
 327         for (i = 0; value[i]; i++)
 328                 switch (value[i]) {
 329                 case '\n': write(fd, "\\n", 2); break;
 330                 case '\t': write(fd, "\\t", 2); break;
 331                 case '"': case '\\': write(fd, "\\", 1);
 332                 default: write(fd, value+i, 1);
 333         }
 334         write(fd, "\n", 1);
 335 }
 336
 337 int git_config_set(const char* key, const char* value)
 338 {
 339         return git_config_set_multivar(key, value, NULL);
 340 }
 341
 342 /*
 343  * If value==NULL, unset in (remove from) config,
 344  * if value_regex!=NULL, disregard key/value pairs where value does not match.
 345  *
 346  * Returns 0 on success.
 347  *
 348  * This function does this:
 349  *
 350  * - it locks the config file by creating ".git/config.lock"
 351  *
 352  * - it then parses the config using store_aux() as validator to find
 353  *   the position on the key/value pair to replace. If it is to be unset,
 354  *   it must be found exactly once.
 355  *
 356  * - the config file is mmap()ed and the part before the match (if any) is
 357  *   written to the lock file, then the changed part and the rest.
 358  *
 359  * - the config file is removed and the lock file rename()d to it.
 360  *
 361  */
 362 int git_config_set_multivar(const char* key, const char* value,
 363         const char* value_regex)
 364 {
 365         int i;
 366         struct stat st;
 367         int fd;
 368         char* config_file = strdup(git_path("config"));
 369         char* lock_file = strdup(git_path("config.lock"));
 370
 371         /*
 372          * Since "key" actually contains the section name and the real
 373          * key name separated by a dot, we have to know where the dot is.
 374          */
 375         for (store.baselen = 0;
 376                         key[store.baselen] != '.' && key[store.baselen];
 377                         store.baselen++);
 378         if (!key[store.baselen] || !key[store.baselen+1]) {
 379                 fprintf(stderr, "key does not contain a section: %s\n", key);
 380                 return 2;
 381         }
 382
 383         /*
 384          * Validate the key and while at it, lower case it for matching.
 385          */
 386         store.key = (char*)malloc(strlen(key)+1);
 387         for (i = 0; key[i]; i++)
 388                 if (i != store.baselen && (!isalnum(key[i]) ||
 389                                 (i == store.baselen+1 && !isalpha(key[i])))) {
 390                         fprintf(stderr, "invalid key: %s\n", key);
 391                         free(store.key);
 392                         return 1;
 393                 } else
 394                         store.key[i] = tolower(key[i]);
 395
 396         /*
 397          * The lock_file serves a purpose in addition to locking: the new
 398          * contents of .git/config will be written into it.
 399          */
 400         fd = open(lock_file, O_WRONLY | O_CREAT | O_EXCL, 0666);
 401         if (fd < 0) {
 402                 fprintf(stderr, "could not lock config file\n");
 403                 free(store.key);
 404                 return -1;
 405         }
 406
 407         /*
 408          * If .git/config does not exist yet, write a minimal version.
 409          */
 410         if (stat(config_file, &st)) {
 411                 static const char contents[] =
 412                         "#\n"
 413                         "# This is the config file\n"
 414                         "#\n"
 415                         "\n";
 416
 417                 free(store.key);
 418
 419                 /* if nothing to unset, error out */
 420                 if (value == NULL) {
 421                         close(fd);
 422                         unlink(lock_file);
 423                         return 5;
 424                 }
 425
 426                 store.key = (char*)key;
 427
 428                 write(fd, contents, sizeof(contents)-1);
 429                 store_write_section(fd, key);
 430                 store_write_pair(fd, key, value);
 431         } else{
 432                 int in_fd;
 433                 char* contents;
 434                 int offset, new_line = 0;
 435
 436                 if (value_regex == NULL)
 437                         store.value_regex = NULL;
 438                 else {
 439                         store.value_regex = (regex_t*)malloc(sizeof(regex_t));
 440                         if (regcomp(store.value_regex, value_regex,
 441                                         REG_EXTENDED)) {
 442                                 fprintf(stderr, "Invalid pattern: %s",
 443                                         value_regex);
 444                                 free(store.value_regex);
 445                                 return 6;
 446                         }
 447                 }
 448
 449                 store.offset = 0;
 450                 store.state = START;
 451                 store.seen = 0;
 452
 453                 /*
 454                  * After this, store.offset will contain the *end* offset
 455                  * of the last match, or remain at 0 if no match was found.
 456                  * As a side effect, we make sure to transform only a valid
 457                  * existing config file.
 458                  */
 459                 if (git_config(store_aux)) {
 460                         fprintf(stderr, "invalid config file\n");
 461                         free(store.key);
 462                         if (store.value_regex != NULL) {
 463                                 regfree(store.value_regex);
 464                                 free(store.value_regex);
 465                         }
 466                         return 3;
 467                 }
 468
 469                 free(store.key);
 470                 if (store.value_regex != NULL) {
 471                         regfree(store.value_regex);
 472                         free(store.value_regex);
 473                 }
 474
 475                 /* if nothing to unset, error out */
 476                 if (store.seen == 0 && value == NULL) {
 477                         close(fd);
 478                         unlink(lock_file);
 479                         return 5;
 480                 }
 481
 482                 store.key = (char*)key;
 483
 484                 in_fd = open(config_file, O_RDONLY, 0666);
 485                 contents = mmap(NULL, st.st_size, PROT_READ,
 486                         MAP_PRIVATE, in_fd, 0);
 487                 close(in_fd);
 488
 489                 if (store.offset == 0) {
 490                         store.offset = offset = st.st_size;
 491                 } else if (store.state != KEY_SEEN) {
 492                         offset = store.offset;
 493                 } else {
 494                         int equal_offset = st.st_size,
 495                                 bracket_offset = st.st_size;
 496
 497                         if (value == NULL && store.seen > 1) {
 498                                 fprintf(stderr, "Cannot remove multivar (%s has %d values\n", key, store.seen);
 499                                 close(fd);
 500                                 unlink(lock_file);
 501                                 return 7;
 502                         }
 503                         for (offset = store.offset-2; offset > 0
 504                                         && contents[offset] != '\n'; offset--)
 505                                 switch (contents[offset]) {
 506                                 case '=': equal_offset = offset; break;
 507                                 case ']': bracket_offset = offset; break;
 508                                 }
 509                         if (bracket_offset < equal_offset) {
 510                                 new_line = 1;
 511                                 offset = bracket_offset+1;
 512                         } else
 513                                 offset++;
 514                 }
 515
 516                 /* write the first part of the config */
 517                 write(fd, contents, offset);
 518                 if (new_line)
 519                         write(fd, "\n", 1);
 520
 521                 /* write the pair (value == NULL means unset) */
 522                 if (value != NULL) {
 523                         if (store.state == START)
 524                                 store_write_section(fd, key);
 525                         store_write_pair(fd, key, value);
 526                 }
 527
 528                 /* write the rest of the config */
 529                 if (store.offset < st.st_size)
 530                         write(fd, contents + store.offset,
 531                                 st.st_size - store.offset);
 532
 533                 munmap(contents, st.st_size);
 534                 unlink(config_file);
 535         }
 536
 537         close(fd);
 538
 539         if (rename(lock_file, config_file) < 0) {
 540                 fprintf(stderr, "Could not rename the lock file?\n");
 541                 return 4;
 542         }
 543
 544         return 0;
 545 }
 546