refs.c

   1 #include "cache.h"
   2 #include "refs.h"
   3 #include "object.h"
   4 #include "tag.h"
   5 #include "dir.h"
   6
   7 /* ISSYMREF=01 and ISPACKED=02 are public interfaces */
   8 #define REF_KNOWS_PEELED 04
   9
  10 struct ref_list {
  11         struct ref_list *next;
  12         unsigned char flag; /* ISSYMREF? ISPACKED? */
  13         unsigned char sha1[20];
  14         unsigned char peeled[20];
  15         char name[FLEX_ARRAY];
  16 };
  17
  18 static const char *parse_ref_line(char *line, unsigned char *sha1)
  19 {
  20         /*
  21          * 42: the answer to everything.
  22          *
  23          * In this case, it happens to be the answer to
  24          *  40 (length of sha1 hex representation)
  25          *  +1 (space in between hex and name)
  26          *  +1 (newline at the end of the line)
  27          */
  28         int len = strlen(line) - 42;
  29
  30         if (len <= 0)
  31                 return NULL;
  32         if (get_sha1_hex(line, sha1) < 0)
  33                 return NULL;
  34         if (!isspace(line[40]))
  35                 return NULL;
  36         line += 41;
  37         if (isspace(*line))
  38                 return NULL;
  39         if (line[len] != '\n')
  40                 return NULL;
  41         line[len] = 0;
  42
  43         return line;
  44 }
  45
  46 static struct ref_list *add_ref(const char *name, const unsigned char *sha1,
  47                                 int flag, struct ref_list *list,
  48                                 struct ref_list **new_entry)
  49 {
  50         int len;
  51         struct ref_list *entry;
  52
  53         /* Allocate it and add it in.. */
  54         len = strlen(name) + 1;
  55         entry = xmalloc(sizeof(struct ref_list) + len);
  56         hashcpy(entry->sha1, sha1);
  57         hashclr(entry->peeled);
  58         memcpy(entry->name, name, len);
  59         entry->flag = flag;
  60         entry->next = list;
  61         if (new_entry)
  62                 *new_entry = entry;
  63         return entry;
  64 }
  65
  66 /* merge sort the ref list */
  67 static struct ref_list *sort_ref_list(struct ref_list *list)
  68 {
  69         int psize, qsize, last_merge_count, cmp;
  70         struct ref_list *p, *q, *l, *e;
  71         struct ref_list *new_list = list;
  72         int k = 1;
  73         int merge_count = 0;
  74
  75         if (!list)
  76                 return list;
  77
  78         do {
  79                 last_merge_count = merge_count;
  80                 merge_count = 0;
  81
  82                 psize = 0;
  83
  84                 p = new_list;
  85                 q = new_list;
  86                 new_list = NULL;
  87                 l = NULL;
  88
  89                 while (p) {
  90                         merge_count++;
  91
  92                         while (psize < k && q->next) {
  93                                 q = q->next;
  94                                 psize++;
  95                         }
  96                         qsize = k;
  97
  98                         while ((psize > 0) || (qsize > 0 && q)) {
  99                                 if (qsize == 0 || !q) {
 100                                         e = p;
 101                                         p = p->next;
 102                                         psize--;
 103                                 } else if (psize == 0) {
 104                                         e = q;
 105                                         q = q->next;
 106                                         qsize--;
 107                                 } else {
 108                                         cmp = strcmp(q->name, p->name);
 109                                         if (cmp < 0) {
 110                                                 e = q;
 111                                                 q = q->next;
 112                                                 qsize--;
 113                                         } else if (cmp > 0) {
 114                                                 e = p;
 115                                                 p = p->next;
 116                                                 psize--;
 117                                         } else {
 118                                                 if (hashcmp(q->sha1, p->sha1))
 119                                                         die("Duplicated ref, and SHA1s don't match: %s",
 120                                                             q->name);
 121                                                 warning("Duplicated ref: %s", q->name);
 122                                                 e = q;
 123                                                 q = q->next;
 124                                                 qsize--;
 125                                                 free(e);
 126                                                 e = p;
 127                                                 p = p->next;
 128                                                 psize--;
 129                                         }
 130                                 }
 131
 132                                 e->next = NULL;
 133
 134                                 if (l)
 135                                         l->next = e;
 136                                 if (!new_list)
 137                                         new_list = e;
 138                                 l = e;
 139                         }
 140
 141                         p = q;
 142                 };
 143
 144                 k = k * 2;
 145         } while ((last_merge_count != merge_count) || (last_merge_count != 1));
 146
 147         return new_list;
 148 }
 149
 150 /*
 151  * Future: need to be in "struct repository"
 152  * when doing a full libification.
 153  */
 154 static struct cached_refs {
 155         char did_loose;
 156         char did_packed;
 157         struct ref_list *loose;
 158         struct ref_list *packed;
 159 } cached_refs;
 160 static struct ref_list *current_ref;
 161
 162 static void free_ref_list(struct ref_list *list)
 163 {
 164         struct ref_list *next;
 165         for ( ; list; list = next) {
 166                 next = list->next;
 167                 free(list);
 168         }
 169 }
 170
 171 static void invalidate_cached_refs(void)
 172 {
 173         struct cached_refs *ca = &cached_refs;
 174
 175         if (ca->did_loose && ca->loose)
 176                 free_ref_list(ca->loose);
 177         if (ca->did_packed && ca->packed)
 178                 free_ref_list(ca->packed);
 179         ca->loose = ca->packed = NULL;
 180         ca->did_loose = ca->did_packed = 0;
 181 }
 182
 183 static void read_packed_refs(FILE *f, struct cached_refs *cached_refs)
 184 {
 185         struct ref_list *list = NULL;
 186         struct ref_list *last = NULL;
 187         char refline[PATH_MAX];
 188         int flag = REF_ISPACKED;
 189
 190         while (fgets(refline, sizeof(refline), f)) {
 191                 unsigned char sha1[20];
 192                 const char *name;
 193                 static const char header[] = "# pack-refs with:";
 194
 195                 if (!strncmp(refline, header, sizeof(header)-1)) {
 196                         const char *traits = refline + sizeof(header) - 1;
 197                         if (strstr(traits, " peeled "))
 198                                 flag |= REF_KNOWS_PEELED;
 199                         /* perhaps other traits later as well */
 200                         continue;
 201                 }
 202
 203                 name = parse_ref_line(refline, sha1);
 204                 if (name) {
 205                         list = add_ref(name, sha1, flag, list, &last);
 206                         continue;
 207                 }
 208                 if (last &&
 209                     refline[0] == '^' &&
 210                     strlen(refline) == 42 &&
 211                     refline[41] == '\n' &&
 212                     !get_sha1_hex(refline + 1, sha1))
 213                         hashcpy(last->peeled, sha1);
 214         }
 215         cached_refs->packed = sort_ref_list(list);
 216 }
 217
 218 static struct ref_list *get_packed_refs(void)
 219 {
 220         if (!cached_refs.did_packed) {
 221                 FILE *f = fopen(git_path("packed-refs"), "r");
 222                 cached_refs.packed = NULL;
 223                 if (f) {
 224                         read_packed_refs(f, &cached_refs);
 225                         fclose(f);
 226                 }
 227                 cached_refs.did_packed = 1;
 228         }
 229         return cached_refs.packed;
 230 }
 231
 232 static struct ref_list *get_ref_dir(const char *base, struct ref_list *list)
 233 {
 234         DIR *dir = opendir(git_path("%s", base));
 235
 236         if (dir) {
 237                 struct dirent *de;
 238                 int baselen = strlen(base);
 239                 char *ref = xmalloc(baselen + 257);
 240
 241                 memcpy(ref, base, baselen);
 242                 if (baselen && base[baselen-1] != '/')
 243                         ref[baselen++] = '/';
 244
 245                 while ((de = readdir(dir)) != NULL) {
 246                         unsigned char sha1[20];
 247                         struct stat st;
 248                         int flag;
 249                         int namelen;
 250
 251                         if (de->d_name[0] == '.')
 252                                 continue;
 253                         namelen = strlen(de->d_name);
 254                         if (namelen > 255)
 255                                 continue;
 256                         if (has_extension(de->d_name, ".lock"))
 257                                 continue;
 258                         memcpy(ref + baselen, de->d_name, namelen+1);
 259                         if (stat(git_path("%s", ref), &st) < 0)
 260                                 continue;
 261                         if (S_ISDIR(st.st_mode)) {
 262                                 list = get_ref_dir(ref, list);
 263                                 continue;
 264                         }
 265                         if (!resolve_ref(ref, sha1, 1, &flag)) {
 266                                 error("%s points nowhere!", ref);
 267                                 continue;
 268                         }
 269                         list = add_ref(ref, sha1, flag, list, NULL);
 270                 }
 271                 free(ref);
 272                 closedir(dir);
 273         }
 274         return sort_ref_list(list);
 275 }
 276
 277 static struct ref_list *get_loose_refs(void)
 278 {
 279         if (!cached_refs.did_loose) {
 280                 cached_refs.loose = get_ref_dir("refs", NULL);
 281                 cached_refs.did_loose = 1;
 282         }
 283         return cached_refs.loose;
 284 }
 285
 286 /* We allow "recursive" symbolic refs. Only within reason, though */
 287 #define MAXDEPTH 5
 288 #define MAXREFLEN (1024)
 289
 290 static int resolve_gitlink_packed_ref(char *name, int pathlen, const char *refname, unsigned char *result)
 291 {
 292         FILE *f;
 293         struct cached_refs refs;
 294         struct ref_list *ref;
 295         int retval;
 296
 297         strcpy(name + pathlen, "packed-refs");
 298         f = fopen(name, "r");
 299         if (!f)
 300                 return -1;
 301         read_packed_refs(f, &refs);
 302         fclose(f);
 303         ref = refs.packed;
 304         retval = -1;
 305         while (ref) {
 306                 if (!strcmp(ref->name, refname)) {
 307                         retval = 0;
 308                         memcpy(result, ref->sha1, 20);
 309                         break;
 310                 }
 311                 ref = ref->next;
 312         }
 313         free_ref_list(refs.packed);
 314         return retval;
 315 }
 316
 317 static int resolve_gitlink_ref_recursive(char *name, int pathlen, const char *refname, unsigned char *result, int recursion)
 318 {
 319         int fd, len = strlen(refname);
 320         char buffer[128], *p;
 321
 322         if (recursion > MAXDEPTH || len > MAXREFLEN)
 323                 return -1;
 324         memcpy(name + pathlen, refname, len+1);
 325         fd = open(name, O_RDONLY);
 326         if (fd < 0)
 327                 return resolve_gitlink_packed_ref(name, pathlen, refname, result);
 328
 329         len = read(fd, buffer, sizeof(buffer)-1);
 330         close(fd);
 331         if (len < 0)
 332                 return -1;
 333         while (len && isspace(buffer[len-1]))
 334                 len--;
 335         buffer[len] = 0;
 336
 337         /* Was it a detached head or an old-fashioned symlink? */
 338         if (!get_sha1_hex(buffer, result))
 339                 return 0;
 340
 341         /* Symref? */
 342         if (strncmp(buffer, "ref:", 4))
 343                 return -1;
 344         p = buffer + 4;
 345         while (isspace(*p))
 346                 p++;
 347
 348         return resolve_gitlink_ref_recursive(name, pathlen, p, result, recursion+1);
 349 }
 350
 351 int resolve_gitlink_ref(const char *path, const char *refname, unsigned char *result)
 352 {
 353         int len = strlen(path), retval;
 354         char *gitdir;
 355         const char *tmp;
 356
 357         while (len && path[len-1] == '/')
 358                 len--;
 359         if (!len)
 360                 return -1;
 361         gitdir = xmalloc(len + MAXREFLEN + 8);
 362         memcpy(gitdir, path, len);
 363         memcpy(gitdir + len, "/.git", 6);
 364         len += 5;
 365
 366         tmp = read_gitfile_gently(gitdir);
 367         if (tmp) {
 368                 free(gitdir);
 369                 len = strlen(tmp);
 370                 gitdir = xmalloc(len + MAXREFLEN + 3);
 371                 memcpy(gitdir, tmp, len);
 372         }
 373         gitdir[len] = '/';
 374         gitdir[++len] = '\0';
 375         retval = resolve_gitlink_ref_recursive(gitdir, len, refname, result, 0);
 376         free(gitdir);
 377         return retval;
 378 }
 379
 380 const char *resolve_ref(const char *ref, unsigned char *sha1, int reading, int *flag)
 381 {
 382         int depth = MAXDEPTH, len;
 383         char buffer[256];
 384         static char ref_buffer[256];
 385
 386         if (flag)
 387                 *flag = 0;
 388
 389         for (;;) {
 390                 const char *path = git_path("%s", ref);
 391                 struct stat st;
 392                 char *buf;
 393                 int fd;
 394
 395                 if (--depth < 0)
 396                         return NULL;
 397
 398                 /* Special case: non-existing file.
 399                  * Not having the refs/heads/new-branch is OK
 400                  * if we are writing into it, so is .git/HEAD
 401                  * that points at refs/heads/master still to be
 402                  * born.  It is NOT OK if we are resolving for
 403                  * reading.
 404                  */
 405                 if (lstat(path, &st) < 0) {
 406                         struct ref_list *list = get_packed_refs();
 407                         while (list) {
 408                                 if (!strcmp(ref, list->name)) {
 409                                         hashcpy(sha1, list->sha1);
 410                                         if (flag)
 411                                                 *flag |= REF_ISPACKED;
 412                                         return ref;
 413                                 }
 414                                 list = list->next;
 415                         }
 416                         if (reading || errno != ENOENT)
 417                                 return NULL;
 418                         hashclr(sha1);
 419                         return ref;
 420                 }
 421
 422                 /* Follow "normalized" - ie "refs/.." symlinks by hand */
 423                 if (S_ISLNK(st.st_mode)) {
 424                         len = readlink(path, buffer, sizeof(buffer)-1);
 425                         if (len >= 5 && !memcmp("refs/", buffer, 5)) {
 426                                 buffer[len] = 0;
 427                                 strcpy(ref_buffer, buffer);
 428                                 ref = ref_buffer;
 429                                 if (flag)
 430                                         *flag |= REF_ISSYMREF;
 431                                 continue;
 432                         }
 433                 }
 434
 435                 /* Is it a directory? */
 436                 if (S_ISDIR(st.st_mode)) {
 437                         errno = EISDIR;
 438                         return NULL;
 439                 }
 440
 441                 /*
 442                  * Anything else, just open it and try to use it as
 443                  * a ref
 444                  */
 445                 fd = open(path, O_RDONLY);
 446                 if (fd < 0)
 447                         return NULL;
 448                 len = read_in_full(fd, buffer, sizeof(buffer)-1);
 449                 close(fd);
 450
 451                 /*
 452                  * Is it a symbolic ref?
 453                  */
 454                 if (len < 4 || memcmp("ref:", buffer, 4))
 455                         break;
 456                 buf = buffer + 4;
 457                 len -= 4;
 458                 while (len && isspace(*buf))
 459                         buf++, len--;
 460                 while (len && isspace(buf[len-1]))
 461                         len--;
 462                 buf[len] = 0;
 463                 memcpy(ref_buffer, buf, len + 1);
 464                 ref = ref_buffer;
 465                 if (flag)
 466                         *flag |= REF_ISSYMREF;
 467         }
 468         if (len < 40 || get_sha1_hex(buffer, sha1))
 469                 return NULL;
 470         return ref;
 471 }
 472
 473 int read_ref(const char *ref, unsigned char *sha1)
 474 {
 475         if (resolve_ref(ref, sha1, 1, NULL))
 476                 return 0;
 477         return -1;
 478 }
 479
 480 static int do_one_ref(const char *base, each_ref_fn fn, int trim,
 481                       void *cb_data, struct ref_list *entry)
 482 {
 483         if (strncmp(base, entry->name, trim))
 484                 return 0;
 485         if (is_null_sha1(entry->sha1))
 486                 return 0;
 487         if (!has_sha1_file(entry->sha1)) {
 488                 error("%s does not point to a valid object!", entry->name);
 489                 return 0;
 490         }
 491         current_ref = entry;
 492         return fn(entry->name + trim, entry->sha1, entry->flag, cb_data);
 493 }
 494
 495 int peel_ref(const char *ref, unsigned char *sha1)
 496 {
 497         int flag;
 498         unsigned char base[20];
 499         struct object *o;
 500
 501         if (current_ref && (current_ref->name == ref
 502                 || !strcmp(current_ref->name, ref))) {
 503                 if (current_ref->flag & REF_KNOWS_PEELED) {
 504                         hashcpy(sha1, current_ref->peeled);
 505                         return 0;
 506                 }
 507                 hashcpy(base, current_ref->sha1);
 508                 goto fallback;
 509         }
 510
 511         if (!resolve_ref(ref, base, 1, &flag))
 512                 return -1;
 513
 514         if ((flag & REF_ISPACKED)) {
 515                 struct ref_list *list = get_packed_refs();
 516
 517                 while (list) {
 518                         if (!strcmp(list->name, ref)) {
 519                                 if (list->flag & REF_KNOWS_PEELED) {
 520                                         hashcpy(sha1, list->peeled);
 521                                         return 0;
 522                                 }
 523                                 /* older pack-refs did not leave peeled ones */
 524                                 break;
 525                         }
 526                         list = list->next;
 527                 }
 528         }
 529
 530 fallback:
 531         o = parse_object(base);
 532         if (o && o->type == OBJ_TAG) {
 533                 o = deref_tag(o, ref, 0);
 534                 if (o) {
 535                         hashcpy(sha1, o->sha1);
 536                         return 0;
 537                 }
 538         }
 539         return -1;
 540 }
 541
 542 static int do_for_each_ref(const char *base, each_ref_fn fn, int trim,
 543                            void *cb_data)
 544 {
 545         int retval = 0;
 546         struct ref_list *packed = get_packed_refs();
 547         struct ref_list *loose = get_loose_refs();
 548
 549         while (packed && loose) {
 550                 struct ref_list *entry;
 551                 int cmp = strcmp(packed->name, loose->name);
 552                 if (!cmp) {
 553                         packed = packed->next;
 554                         continue;
 555                 }
 556                 if (cmp > 0) {
 557                         entry = loose;
 558                         loose = loose->next;
 559                 } else {
 560                         entry = packed;
 561                         packed = packed->next;
 562                 }
 563                 retval = do_one_ref(base, fn, trim, cb_data, entry);
 564                 if (retval)
 565                         goto end_each;
 566         }
 567
 568         for (packed = packed ? packed : loose; packed; packed = packed->next) {
 569                 retval = do_one_ref(base, fn, trim, cb_data, packed);
 570                 if (retval)
 571                         goto end_each;
 572         }
 573
 574 end_each:
 575         current_ref = NULL;
 576         return retval;
 577 }
 578
 579 int head_ref(each_ref_fn fn, void *cb_data)
 580 {
 581         unsigned char sha1[20];
 582         int flag;
 583
 584         if (resolve_ref("HEAD", sha1, 1, &flag))
 585                 return fn("HEAD", sha1, flag, cb_data);
 586         return 0;
 587 }
 588
 589 int for_each_ref(each_ref_fn fn, void *cb_data)
 590 {
 591         return do_for_each_ref("refs/", fn, 0, cb_data);
 592 }
 593
 594 int for_each_tag_ref(each_ref_fn fn, void *cb_data)
 595 {
 596         return do_for_each_ref("refs/tags/", fn, 10, cb_data);
 597 }
 598
 599 int for_each_branch_ref(each_ref_fn fn, void *cb_data)
 600 {
 601         return do_for_each_ref("refs/heads/", fn, 11, cb_data);
 602 }
 603
 604 int for_each_remote_ref(each_ref_fn fn, void *cb_data)
 605 {
 606         return do_for_each_ref("refs/remotes/", fn, 13, cb_data);
 607 }
 608
 609 /*
 610  * Make sure "ref" is something reasonable to have under ".git/refs/";
 611  * We do not like it if:
 612  *
 613  * - any path component of it begins with ".", or
 614  * - it has double dots "..", or
 615  * - it has ASCII control character, "~", "^", ":" or SP, anywhere, or
 616  * - it ends with a "/".
 617  */
 618
 619 static inline int bad_ref_char(int ch)
 620 {
 621         if (((unsigned) ch) <= ' ' ||
 622             ch == '~' || ch == '^' || ch == ':')
 623                 return 1;
 624         /* 2.13 Pattern Matching Notation */
 625         if (ch == '?' || ch == '[') /* Unsupported */
 626                 return 1;
 627         if (ch == '*') /* Supported at the end */
 628                 return 2;
 629         return 0;
 630 }
 631
 632 int check_ref_format(const char *ref)
 633 {
 634         int ch, level, bad_type;
 635         const char *cp = ref;
 636
 637         level = 0;
 638         while (1) {
 639                 while ((ch = *cp++) == '/')
 640                         ; /* tolerate duplicated slashes */
 641                 if (!ch)
 642                         /* should not end with slashes */
 643                         return CHECK_REF_FORMAT_ERROR;
 644
 645                 /* we are at the beginning of the path component */
 646                 if (ch == '.')
 647                         return CHECK_REF_FORMAT_ERROR;
 648                 bad_type = bad_ref_char(ch);
 649                 if (bad_type) {
 650                         return (bad_type == 2 && !*cp)
 651                                 ? CHECK_REF_FORMAT_WILDCARD
 652                                 : CHECK_REF_FORMAT_ERROR;
 653                 }
 654
 655                 /* scan the rest of the path component */
 656                 while ((ch = *cp++) != 0) {
 657                         bad_type = bad_ref_char(ch);
 658                         if (bad_type) {
 659                                 return (bad_type == 2 && !*cp)
 660                                         ? CHECK_REF_FORMAT_WILDCARD
 661                                         : CHECK_REF_FORMAT_ERROR;
 662                         }
 663                         if (ch == '/')
 664                                 break;
 665                         if (ch == '.' && *cp == '.')
 666                                 return CHECK_REF_FORMAT_ERROR;
 667                 }
 668                 level++;
 669                 if (!ch) {
 670                         if (level < 2)
 671                                 return CHECK_REF_FORMAT_ONELEVEL;
 672                         return CHECK_REF_FORMAT_OK;
 673                 }
 674         }
 675 }
 676
 677 const char *ref_rev_parse_rules[] = {
 678         "%.*s",
 679         "refs/%.*s",
 680         "refs/tags/%.*s",
 681         "refs/heads/%.*s",
 682         "refs/remotes/%.*s",
 683         "refs/remotes/%.*s/HEAD",
 684         NULL
 685 };
 686
 687 const char *ref_fetch_rules[] = {
 688         "%.*s",
 689         "refs/%.*s",
 690         "refs/heads/%.*s",
 691         NULL
 692 };
 693
 694 int refname_match(const char *abbrev_name, const char *full_name, const char **rules)
 695 {
 696         const char **p;
 697         const int abbrev_name_len = strlen(abbrev_name);
 698
 699         for (p = rules; *p; p++) {
 700                 if (!strcmp(full_name, mkpath(*p, abbrev_name_len, abbrev_name))) {
 701                         return 1;
 702                 }
 703         }
 704
 705         return 0;
 706 }
 707
 708 static struct ref_lock *verify_lock(struct ref_lock *lock,
 709         const unsigned char *old_sha1, int mustexist)
 710 {
 711         if (!resolve_ref(lock->ref_name, lock->old_sha1, mustexist, NULL)) {
 712                 error("Can't verify ref %s", lock->ref_name);
 713                 unlock_ref(lock);
 714                 return NULL;
 715         }
 716         if (hashcmp(lock->old_sha1, old_sha1)) {
 717                 error("Ref %s is at %s but expected %s", lock->ref_name,
 718                         sha1_to_hex(lock->old_sha1), sha1_to_hex(old_sha1));
 719                 unlock_ref(lock);
 720                 return NULL;
 721         }
 722         return lock;
 723 }
 724
 725 static int remove_empty_directories(const char *file)
 726 {
 727         /* we want to create a file but there is a directory there;
 728          * if that is an empty directory (or a directory that contains
 729          * only empty directories), remove them.
 730          */
 731         struct strbuf path;
 732         int result;
 733
 734         strbuf_init(&path, 20);
 735         strbuf_addstr(&path, file);
 736
 737         result = remove_dir_recursively(&path, 1);
 738
 739         strbuf_release(&path);
 740
 741         return result;
 742 }
 743
 744 static int is_refname_available(const char *ref, const char *oldref,
 745                                 struct ref_list *list, int quiet)
 746 {
 747         int namlen = strlen(ref); /* e.g. 'foo/bar' */
 748         while (list) {
 749                 /* list->name could be 'foo' or 'foo/bar/baz' */
 750                 if (!oldref || strcmp(oldref, list->name)) {
 751                         int len = strlen(list->name);
 752                         int cmplen = (namlen < len) ? namlen : len;
 753                         const char *lead = (namlen < len) ? list->name : ref;
 754                         if (!strncmp(ref, list->name, cmplen) &&
 755                             lead[cmplen] == '/') {
 756                                 if (!quiet)
 757                                         error("'%s' exists; cannot create '%s'",
 758                                               list->name, ref);
 759                                 return 0;
 760                         }
 761                 }
 762                 list = list->next;
 763         }
 764         return 1;
 765 }
 766
 767 static struct ref_lock *lock_ref_sha1_basic(const char *ref, const unsigned char *old_sha1, int flags, int *type_p)
 768 {
 769         char *ref_file;
 770         const char *orig_ref = ref;
 771         struct ref_lock *lock;
 772         struct stat st;
 773         int last_errno = 0;
 774         int type;
 775         int mustexist = (old_sha1 && !is_null_sha1(old_sha1));
 776
 777         lock = xcalloc(1, sizeof(struct ref_lock));
 778         lock->lock_fd = -1;
 779
 780         ref = resolve_ref(ref, lock->old_sha1, mustexist, &type);
 781         if (!ref && errno == EISDIR) {
 782                 /* we are trying to lock foo but we used to
 783                  * have foo/bar which now does not exist;
 784                  * it is normal for the empty directory 'foo'
 785                  * to remain.
 786                  */
 787                 ref_file = git_path("%s", orig_ref);
 788                 if (remove_empty_directories(ref_file)) {
 789                         last_errno = errno;
 790                         error("there are still refs under '%s'", orig_ref);
 791                         goto error_return;
 792                 }
 793                 ref = resolve_ref(orig_ref, lock->old_sha1, mustexist, &type);
 794         }
 795         if (type_p)
 796             *type_p = type;
 797         if (!ref) {
 798                 last_errno = errno;
 799                 error("unable to resolve reference %s: %s",
 800                         orig_ref, strerror(errno));
 801                 goto error_return;
 802         }
 803         /* When the ref did not exist and we are creating it,
 804          * make sure there is no existing ref that is packed
 805          * whose name begins with our refname, nor a ref whose
 806          * name is a proper prefix of our refname.
 807          */
 808         if (is_null_sha1(lock->old_sha1) &&
 809             !is_refname_available(ref, NULL, get_packed_refs(), 0))
 810                 goto error_return;
 811
 812         lock->lk = xcalloc(1, sizeof(struct lock_file));
 813
 814         if (flags & REF_NODEREF)
 815                 ref = orig_ref;
 816         lock->ref_name = xstrdup(ref);
 817         lock->orig_ref_name = xstrdup(orig_ref);
 818         ref_file = git_path("%s", ref);
 819         if (lstat(ref_file, &st) && errno == ENOENT)
 820                 lock->force_write = 1;
 821         if ((flags & REF_NODEREF) && (type & REF_ISSYMREF))
 822                 lock->force_write = 1;
 823
 824         if (safe_create_leading_directories(ref_file)) {
 825                 last_errno = errno;
 826                 error("unable to create directory for %s", ref_file);
 827                 goto error_return;
 828         }
 829         lock->lock_fd = hold_lock_file_for_update(lock->lk, ref_file, 1);
 830
 831         return old_sha1 ? verify_lock(lock, old_sha1, mustexist) : lock;
 832
 833  error_return:
 834         unlock_ref(lock);
 835         errno = last_errno;
 836         return NULL;
 837 }
 838
 839 struct ref_lock *lock_ref_sha1(const char *ref, const unsigned char *old_sha1)
 840 {
 841         char refpath[PATH_MAX];
 842         if (check_ref_format(ref))
 843                 return NULL;
 844         strcpy(refpath, mkpath("refs/%s", ref));
 845         return lock_ref_sha1_basic(refpath, old_sha1, 0, NULL);
 846 }
 847
 848 struct ref_lock *lock_any_ref_for_update(const char *ref, const unsigned char *old_sha1, int flags)
 849 {
 850         switch (check_ref_format(ref)) {
 851         default:
 852                 return NULL;
 853         case 0:
 854         case CHECK_REF_FORMAT_ONELEVEL:
 855                 return lock_ref_sha1_basic(ref, old_sha1, flags, NULL);
 856         }
 857 }
 858
 859 static struct lock_file packlock;
 860
 861 static int repack_without_ref(const char *refname)
 862 {
 863         struct ref_list *list, *packed_ref_list;
 864         int fd;
 865         int found = 0;
 866
 867         packed_ref_list = get_packed_refs();
 868         for (list = packed_ref_list; list; list = list->next) {
 869                 if (!strcmp(refname, list->name)) {
 870                         found = 1;
 871                         break;
 872                 }
 873         }
 874         if (!found)
 875                 return 0;
 876         fd = hold_lock_file_for_update(&packlock, git_path("packed-refs"), 0);
 877         if (fd < 0)
 878                 return error("cannot delete '%s' from packed refs", refname);
 879
 880         for (list = packed_ref_list; list; list = list->next) {
 881                 char line[PATH_MAX + 100];
 882                 int len;
 883
 884                 if (!strcmp(refname, list->name))
 885                         continue;
 886                 len = snprintf(line, sizeof(line), "%s %s\n",
 887                                sha1_to_hex(list->sha1), list->name);
 888                 /* this should not happen but just being defensive */
 889                 if (len > sizeof(line))
 890                         die("too long a refname '%s'", list->name);
 891                 write_or_die(fd, line, len);
 892         }
 893         return commit_lock_file(&packlock);
 894 }
 895
 896 int delete_ref(const char *refname, const unsigned char *sha1)
 897 {
 898         struct ref_lock *lock;
 899         int err, i, ret = 0, flag = 0;
 900
 901         lock = lock_ref_sha1_basic(refname, sha1, 0, &flag);
 902         if (!lock)
 903                 return 1;
 904         if (!(flag & REF_ISPACKED)) {
 905                 /* loose */
 906                 i = strlen(lock->lk->filename) - 5; /* .lock */
 907                 lock->lk->filename[i] = 0;
 908                 err = unlink(lock->lk->filename);
 909                 if (err) {
 910                         ret = 1;
 911                         error("unlink(%s) failed: %s",
 912                               lock->lk->filename, strerror(errno));
 913                 }
 914                 lock->lk->filename[i] = '.';
 915         }
 916         /* removing the loose one could have resurrected an earlier
 917          * packed one.  Also, if it was not loose we need to repack
 918          * without it.
 919          */
 920         ret |= repack_without_ref(refname);
 921
 922         err = unlink(git_path("logs/%s", lock->ref_name));
 923         if (err && errno != ENOENT)
 924                 fprintf(stderr, "warning: unlink(%s) failed: %s",
 925                         git_path("logs/%s", lock->ref_name), strerror(errno));
 926         invalidate_cached_refs();
 927         unlock_ref(lock);
 928         return ret;
 929 }
 930
 931 int rename_ref(const char *oldref, const char *newref, const char *logmsg)
 932 {
 933         static const char renamed_ref[] = "RENAMED-REF";
 934         unsigned char sha1[20], orig_sha1[20];
 935         int flag = 0, logmoved = 0;
 936         struct ref_lock *lock;
 937         struct stat loginfo;
 938         int log = !lstat(git_path("logs/%s", oldref), &loginfo);
 939
 940         if (S_ISLNK(loginfo.st_mode))
 941                 return error("reflog for %s is a symlink", oldref);
 942
 943         if (!resolve_ref(oldref, orig_sha1, 1, &flag))
 944                 return error("refname %s not found", oldref);
 945
 946         if (!is_refname_available(newref, oldref, get_packed_refs(), 0))
 947                 return 1;
 948
 949         if (!is_refname_available(newref, oldref, get_loose_refs(), 0))
 950                 return 1;
 951
 952         lock = lock_ref_sha1_basic(renamed_ref, NULL, 0, NULL);
 953         if (!lock)
 954                 return error("unable to lock %s", renamed_ref);
 955         lock->force_write = 1;
 956         if (write_ref_sha1(lock, orig_sha1, logmsg))
 957                 return error("unable to save current sha1 in %s", renamed_ref);
 958
 959         if (log && rename(git_path("logs/%s", oldref), git_path("tmp-renamed-log")))
 960                 return error("unable to move logfile logs/%s to tmp-renamed-log: %s",
 961                         oldref, strerror(errno));
 962
 963         if (delete_ref(oldref, orig_sha1)) {
 964                 error("unable to delete old %s", oldref);
 965                 goto rollback;
 966         }
 967
 968         if (resolve_ref(newref, sha1, 1, &flag) && delete_ref(newref, sha1)) {
 969                 if (errno==EISDIR) {
 970                         if (remove_empty_directories(git_path("%s", newref))) {
 971                                 error("Directory not empty: %s", newref);
 972                                 goto rollback;
 973                         }
 974                 } else {
 975                         error("unable to delete existing %s", newref);
 976                         goto rollback;
 977                 }
 978         }
 979
 980         if (log && safe_create_leading_directories(git_path("logs/%s", newref))) {
 981                 error("unable to create directory for %s", newref);
 982                 goto rollback;
 983         }
 984
 985  retry:
 986         if (log && rename(git_path("tmp-renamed-log"), git_path("logs/%s", newref))) {
 987                 if (errno==EISDIR || errno==ENOTDIR) {
 988                         /*
 989                          * rename(a, b) when b is an existing
 990                          * directory ought to result in ISDIR, but
 991                          * Solaris 5.8 gives ENOTDIR.  Sheesh.
 992                          */
 993                         if (remove_empty_directories(git_path("logs/%s", newref))) {
 994                                 error("Directory not empty: logs/%s", newref);
 995                                 goto rollback;
 996                         }
 997                         goto retry;
 998                 } else {
 999                         error("unable to move logfile tmp-renamed-log to logs/%s: %s",
1000                                 newref, strerror(errno));
1001                         goto rollback;
1002                 }
1003         }
1004         logmoved = log;
1005
1006         lock = lock_ref_sha1_basic(newref, NULL, 0, NULL);
1007         if (!lock) {
1008                 error("unable to lock %s for update", newref);
1009                 goto rollback;
1010         }
1011
1012         lock->force_write = 1;
1013         hashcpy(lock->old_sha1, orig_sha1);
1014         if (write_ref_sha1(lock, orig_sha1, logmsg)) {
1015                 error("unable to write current sha1 into %s", newref);
1016                 goto rollback;
1017         }
1018
1019         return 0;
1020
1021  rollback:
1022         lock = lock_ref_sha1_basic(oldref, NULL, 0, NULL);
1023         if (!lock) {
1024                 error("unable to lock %s for rollback", oldref);
1025                 goto rollbacklog;
1026         }
1027
1028         lock->force_write = 1;
1029         flag = log_all_ref_updates;
1030         log_all_ref_updates = 0;
1031         if (write_ref_sha1(lock, orig_sha1, NULL))
1032                 error("unable to write current sha1 into %s", oldref);
1033         log_all_ref_updates = flag;
1034
1035  rollbacklog:
1036         if (logmoved && rename(git_path("logs/%s", newref), git_path("logs/%s", oldref)))
1037                 error("unable to restore logfile %s from %s: %s",
1038                         oldref, newref, strerror(errno));
1039         if (!logmoved && log &&
1040             rename(git_path("tmp-renamed-log"), git_path("logs/%s", oldref)))
1041                 error("unable to restore logfile %s from tmp-renamed-log: %s",
1042                         oldref, strerror(errno));
1043
1044         return 1;
1045 }
1046
1047 int close_ref(struct ref_lock *lock)
1048 {
1049         if (close_lock_file(lock->lk))
1050                 return -1;
1051         lock->lock_fd = -1;
1052         return 0;
1053 }
1054
1055 int commit_ref(struct ref_lock *lock)
1056 {
1057         if (commit_lock_file(lock->lk))
1058                 return -1;
1059         lock->lock_fd = -1;
1060         return 0;
1061 }
1062
1063 void unlock_ref(struct ref_lock *lock)
1064 {
1065         /* Do not free lock->lk -- atexit() still looks at them */
1066         if (lock->lk)
1067                 rollback_lock_file(lock->lk);
1068         free(lock->ref_name);
1069         free(lock->orig_ref_name);
1070         free(lock);
1071 }
1072
1073 /*
1074  * copy the reflog message msg to buf, which has been allocated sufficiently
1075  * large, while cleaning up the whitespaces.  Especially, convert LF to space,
1076  * because reflog file is one line per entry.
1077  */
1078 static int copy_msg(char *buf, const char *msg)
1079 {
1080         char *cp = buf;
1081         char c;
1082         int wasspace = 1;
1083
1084         *cp++ = '\t';
1085         while ((c = *msg++)) {
1086                 if (wasspace && isspace(c))
1087                         continue;
1088                 wasspace = isspace(c);
1089                 if (wasspace)
1090                         c = ' ';
1091                 *cp++ = c;
1092         }
1093         while (buf < cp && isspace(cp[-1]))
1094                 cp--;
1095         *cp++ = '\n';
1096         return cp - buf;
1097 }
1098
1099 static int log_ref_write(const char *ref_name, const unsigned char *old_sha1,
1100                          const unsigned char *new_sha1, const char *msg)
1101 {
1102         int logfd, written, oflags = O_APPEND | O_WRONLY;
1103         unsigned maxlen, len;
1104         int msglen;
1105         char *log_file, *logrec;
1106         const char *committer;
1107
1108         if (log_all_ref_updates < 0)
1109                 log_all_ref_updates = !is_bare_repository();
1110
1111         log_file = git_path("logs/%s", ref_name);
1112
1113         if (log_all_ref_updates &&
1114             (!prefixcmp(ref_name, "refs/heads/") ||
1115              !prefixcmp(ref_name, "refs/remotes/") ||
1116              !strcmp(ref_name, "HEAD"))) {
1117                 if (safe_create_leading_directories(log_file) < 0)
1118                         return error("unable to create directory for %s",
1119                                      log_file);
1120                 oflags |= O_CREAT;
1121         }
1122
1123         logfd = open(log_file, oflags, 0666);
1124         if (logfd < 0) {
1125                 if (!(oflags & O_CREAT) && errno == ENOENT)
1126                         return 0;
1127
1128                 if ((oflags & O_CREAT) && errno == EISDIR) {
1129                         if (remove_empty_directories(log_file)) {
1130                                 return error("There are still logs under '%s'",
1131                                              log_file);
1132                         }
1133                         logfd = open(log_file, oflags, 0666);
1134                 }
1135
1136                 if (logfd < 0)
1137                         return error("Unable to append to %s: %s",
1138                                      log_file, strerror(errno));
1139         }
1140
1141         adjust_shared_perm(log_file);
1142
1143         msglen = msg ? strlen(msg) : 0;
1144         committer = git_committer_info(0);
1145         maxlen = strlen(committer) + msglen + 100;
1146         logrec = xmalloc(maxlen);
1147         len = sprintf(logrec, "%s %s %s\n",
1148                       sha1_to_hex(old_sha1),
1149                       sha1_to_hex(new_sha1),
1150                       committer);
1151         if (msglen)
1152                 len += copy_msg(logrec + len - 1, msg) - 1;
1153         written = len <= maxlen ? write_in_full(logfd, logrec, len) : -1;
1154         free(logrec);
1155         if (close(logfd) != 0 || written != len)
1156                 return error("Unable to append to %s", log_file);
1157         return 0;
1158 }
1159
1160 static int is_branch(const char *refname)
1161 {
1162         return !strcmp(refname, "HEAD") || !prefixcmp(refname, "refs/heads/");
1163 }
1164
1165 int write_ref_sha1(struct ref_lock *lock,
1166         const unsigned char *sha1, const char *logmsg)
1167 {
1168         static char term = '\n';
1169         struct object *o;
1170
1171         if (!lock)
1172                 return -1;
1173         if (!lock->force_write && !hashcmp(lock->old_sha1, sha1)) {
1174                 unlock_ref(lock);
1175                 return 0;
1176         }
1177         o = parse_object(sha1);
1178         if (!o) {
1179                 error("Trying to write ref %s with nonexistant object %s",
1180                         lock->ref_name, sha1_to_hex(sha1));
1181                 unlock_ref(lock);
1182                 return -1;
1183         }
1184         if (o->type != OBJ_COMMIT && is_branch(lock->ref_name)) {
1185                 error("Trying to write non-commit object %s to branch %s",
1186                         sha1_to_hex(sha1), lock->ref_name);
1187                 unlock_ref(lock);
1188                 return -1;
1189         }
1190         if (write_in_full(lock->lock_fd, sha1_to_hex(sha1), 40) != 40 ||
1191             write_in_full(lock->lock_fd, &term, 1) != 1
1192                 || close_ref(lock) < 0) {
1193                 error("Couldn't write %s", lock->lk->filename);
1194                 unlock_ref(lock);
1195                 return -1;
1196         }
1197         invalidate_cached_refs();
1198         if (log_ref_write(lock->ref_name, lock->old_sha1, sha1, logmsg) < 0 ||
1199             (strcmp(lock->ref_name, lock->orig_ref_name) &&
1200              log_ref_write(lock->orig_ref_name, lock->old_sha1, sha1, logmsg) < 0)) {
1201                 unlock_ref(lock);
1202                 return -1;
1203         }
1204         if (strcmp(lock->orig_ref_name, "HEAD") != 0) {
1205                 /*
1206                  * Special hack: If a branch is updated directly and HEAD
1207                  * points to it (may happen on the remote side of a push
1208                  * for example) then logically the HEAD reflog should be
1209                  * updated too.
1210                  * A generic solution implies reverse symref information,
1211                  * but finding all symrefs pointing to the given branch
1212                  * would be rather costly for this rare event (the direct
1213                  * update of a branch) to be worth it.  So let's cheat and
1214                  * check with HEAD only which should cover 99% of all usage
1215                  * scenarios (even 100% of the default ones).
1216                  */
1217                 unsigned char head_sha1[20];
1218                 int head_flag;
1219                 const char *head_ref;
1220                 head_ref = resolve_ref("HEAD", head_sha1, 1, &head_flag);
1221                 if (head_ref && (head_flag & REF_ISSYMREF) &&
1222                     !strcmp(head_ref, lock->ref_name))
1223                         log_ref_write("HEAD", lock->old_sha1, sha1, logmsg);
1224         }
1225         if (commit_ref(lock)) {
1226                 error("Couldn't set %s", lock->ref_name);
1227                 unlock_ref(lock);
1228                 return -1;
1229         }
1230         unlock_ref(lock);
1231         return 0;
1232 }
1233
1234 int create_symref(const char *ref_target, const char *refs_heads_master,
1235                   const char *logmsg)
1236 {
1237         const char *lockpath;
1238         char ref[1000];
1239         int fd, len, written;
1240         char *git_HEAD = xstrdup(git_path("%s", ref_target));
1241         unsigned char old_sha1[20], new_sha1[20];
1242
1243         if (logmsg && read_ref(ref_target, old_sha1))
1244                 hashclr(old_sha1);
1245
1246         if (safe_create_leading_directories(git_HEAD) < 0)
1247                 return error("unable to create directory for %s", git_HEAD);
1248
1249 #ifndef NO_SYMLINK_HEAD
1250         if (prefer_symlink_refs) {
1251                 unlink(git_HEAD);
1252                 if (!symlink(refs_heads_master, git_HEAD))
1253                         goto done;
1254                 fprintf(stderr, "no symlink - falling back to symbolic ref\n");
1255         }
1256 #endif
1257
1258         len = snprintf(ref, sizeof(ref), "ref: %s\n", refs_heads_master);
1259         if (sizeof(ref) <= len) {
1260                 error("refname too long: %s", refs_heads_master);
1261                 goto error_free_return;
1262         }
1263         lockpath = mkpath("%s.lock", git_HEAD);
1264         fd = open(lockpath, O_CREAT | O_EXCL | O_WRONLY, 0666);
1265         if (fd < 0) {
1266                 error("Unable to open %s for writing", lockpath);
1267                 goto error_free_return;
1268         }
1269         written = write_in_full(fd, ref, len);
1270         if (close(fd) != 0 || written != len) {
1271                 error("Unable to write to %s", lockpath);
1272                 goto error_unlink_return;
1273         }
1274         if (rename(lockpath, git_HEAD) < 0) {
1275                 error("Unable to create %s", git_HEAD);
1276                 goto error_unlink_return;
1277         }
1278         if (adjust_shared_perm(git_HEAD)) {
1279                 error("Unable to fix permissions on %s", lockpath);
1280         error_unlink_return:
1281                 unlink(lockpath);
1282         error_free_return:
1283                 free(git_HEAD);
1284                 return -1;
1285         }
1286
1287 #ifndef NO_SYMLINK_HEAD
1288         done:
1289 #endif
1290         if (logmsg && !read_ref(refs_heads_master, new_sha1))
1291                 log_ref_write(ref_target, old_sha1, new_sha1, logmsg);
1292
1293         free(git_HEAD);
1294         return 0;
1295 }
1296
1297 static char *ref_msg(const char *line, const char *endp)
1298 {
1299         const char *ep;
1300         line += 82;
1301         ep = memchr(line, '\n', endp - line);
1302         if (!ep)
1303                 ep = endp;
1304         return xmemdupz(line, ep - line);
1305 }
1306
1307 int read_ref_at(const char *ref, unsigned long at_time, int cnt, unsigned char *sha1, char **msg, unsigned long *cutoff_time, int *cutoff_tz, int *cutoff_cnt)
1308 {
1309         const char *logfile, *logdata, *logend, *rec, *lastgt, *lastrec;
1310         char *tz_c;
1311         int logfd, tz, reccnt = 0;
1312         struct stat st;
1313         unsigned long date;
1314         unsigned char logged_sha1[20];
1315         void *log_mapped;
1316         size_t mapsz;
1317
1318         logfile = git_path("logs/%s", ref);
1319         logfd = open(logfile, O_RDONLY, 0);
1320         if (logfd < 0)
1321                 die("Unable to read log %s: %s", logfile, strerror(errno));
1322         fstat(logfd, &st);
1323         if (!st.st_size)
1324                 die("Log %s is empty.", logfile);
1325         mapsz = xsize_t(st.st_size);
1326         log_mapped = xmmap(NULL, mapsz, PROT_READ, MAP_PRIVATE, logfd, 0);
1327         logdata = log_mapped;
1328         close(logfd);
1329
1330         lastrec = NULL;
1331         rec = logend = logdata + st.st_size;
1332         while (logdata < rec) {
1333                 reccnt++;
1334                 if (logdata < rec && *(rec-1) == '\n')
1335                         rec--;
1336                 lastgt = NULL;
1337                 while (logdata < rec && *(rec-1) != '\n') {
1338                         rec--;
1339                         if (*rec == '>')
1340                                 lastgt = rec;
1341                 }
1342                 if (!lastgt)
1343                         die("Log %s is corrupt.", logfile);
1344                 date = strtoul(lastgt + 1, &tz_c, 10);
1345                 if (date <= at_time || cnt == 0) {
1346                         tz = strtoul(tz_c, NULL, 10);
1347                         if (msg)
1348                                 *msg = ref_msg(rec, logend);
1349                         if (cutoff_time)
1350                                 *cutoff_time = date;
1351                         if (cutoff_tz)
1352                                 *cutoff_tz = tz;
1353                         if (cutoff_cnt)
1354                                 *cutoff_cnt = reccnt - 1;
1355                         if (lastrec) {
1356                                 if (get_sha1_hex(lastrec, logged_sha1))
1357                                         die("Log %s is corrupt.", logfile);
1358                                 if (get_sha1_hex(rec + 41, sha1))
1359                                         die("Log %s is corrupt.", logfile);
1360                                 if (hashcmp(logged_sha1, sha1)) {
1361                                         fprintf(stderr,
1362                                                 "warning: Log %s has gap after %s.\n",
1363                                                 logfile, show_date(date, tz, DATE_RFC2822));
1364                                 }
1365                         }
1366                         else if (date == at_time) {
1367                                 if (get_sha1_hex(rec + 41, sha1))
1368                                         die("Log %s is corrupt.", logfile);
1369                         }
1370                         else {
1371                                 if (get_sha1_hex(rec + 41, logged_sha1))
1372                                         die("Log %s is corrupt.", logfile);
1373                                 if (hashcmp(logged_sha1, sha1)) {
1374                                         fprintf(stderr,
1375                                                 "warning: Log %s unexpectedly ended on %s.\n",
1376                                                 logfile, show_date(date, tz, DATE_RFC2822));
1377                                 }
1378                         }
1379                         munmap(log_mapped, mapsz);
1380                         return 0;
1381                 }
1382                 lastrec = rec;
1383                 if (cnt > 0)
1384                         cnt--;
1385         }
1386
1387         rec = logdata;
1388         while (rec < logend && *rec != '>' && *rec != '\n')
1389                 rec++;
1390         if (rec == logend || *rec == '\n')
1391                 die("Log %s is corrupt.", logfile);
1392         date = strtoul(rec + 1, &tz_c, 10);
1393         tz = strtoul(tz_c, NULL, 10);
1394         if (get_sha1_hex(logdata, sha1))
1395                 die("Log %s is corrupt.", logfile);
1396         if (msg)
1397                 *msg = ref_msg(logdata, logend);
1398         munmap(log_mapped, mapsz);
1399
1400         if (cutoff_time)
1401                 *cutoff_time = date;
1402         if (cutoff_tz)
1403                 *cutoff_tz = tz;
1404         if (cutoff_cnt)
1405                 *cutoff_cnt = reccnt;
1406         return 1;
1407 }
1408
1409 int for_each_reflog_ent(const char *ref, each_reflog_ent_fn fn, void *cb_data)
1410 {
1411         const char *logfile;
1412         FILE *logfp;
1413         char buf[1024];
1414         int ret = 0;
1415
1416         logfile = git_path("logs/%s", ref);
1417         logfp = fopen(logfile, "r");
1418         if (!logfp)
1419                 return -1;
1420         while (fgets(buf, sizeof(buf), logfp)) {
1421                 unsigned char osha1[20], nsha1[20];
1422                 char *email_end, *message;
1423                 unsigned long timestamp;
1424                 int len, tz;
1425
1426                 /* old SP new SP name <email> SP time TAB msg LF */
1427                 len = strlen(buf);
1428                 if (len < 83 || buf[len-1] != '\n' ||
1429                     get_sha1_hex(buf, osha1) || buf[40] != ' ' ||
1430                     get_sha1_hex(buf + 41, nsha1) || buf[81] != ' ' ||
1431                     !(email_end = strchr(buf + 82, '>')) ||
1432                     email_end[1] != ' ' ||
1433                     !(timestamp = strtoul(email_end + 2, &message, 10)) ||
1434                     !message || message[0] != ' ' ||
1435                     (message[1] != '+' && message[1] != '-') ||
1436                     !isdigit(message[2]) || !isdigit(message[3]) ||
1437                     !isdigit(message[4]) || !isdigit(message[5]))
1438                         continue; /* corrupt? */
1439                 email_end[1] = '\0';
1440                 tz = strtol(message + 1, NULL, 10);
1441                 if (message[6] != '\t')
1442                         message += 6;
1443                 else
1444                         message += 7;
1445                 ret = fn(osha1, nsha1, buf+82, timestamp, tz, message, cb_data);
1446                 if (ret)
1447                         break;
1448         }
1449         fclose(logfp);
1450         return ret;
1451 }
1452
1453 static int do_for_each_reflog(const char *base, each_ref_fn fn, void *cb_data)
1454 {
1455         DIR *dir = opendir(git_path("logs/%s", base));
1456         int retval = 0;
1457
1458         if (dir) {
1459                 struct dirent *de;
1460                 int baselen = strlen(base);
1461                 char *log = xmalloc(baselen + 257);
1462
1463                 memcpy(log, base, baselen);
1464                 if (baselen && base[baselen-1] != '/')
1465                         log[baselen++] = '/';
1466
1467                 while ((de = readdir(dir)) != NULL) {
1468                         struct stat st;
1469                         int namelen;
1470
1471                         if (de->d_name[0] == '.')
1472                                 continue;
1473                         namelen = strlen(de->d_name);
1474                         if (namelen > 255)
1475                                 continue;
1476                         if (has_extension(de->d_name, ".lock"))
1477                                 continue;
1478                         memcpy(log + baselen, de->d_name, namelen+1);
1479                         if (stat(git_path("logs/%s", log), &st) < 0)
1480                                 continue;
1481                         if (S_ISDIR(st.st_mode)) {
1482                                 retval = do_for_each_reflog(log, fn, cb_data);
1483                         } else {
1484                                 unsigned char sha1[20];
1485                                 if (!resolve_ref(log, sha1, 0, NULL))
1486                                         retval = error("bad ref for %s", log);
1487                                 else
1488                                         retval = fn(log, sha1, 0, cb_data);
1489                         }
1490                         if (retval)
1491                                 break;
1492                 }
1493                 free(log);
1494                 closedir(dir);
1495         }
1496         else if (*base)
1497                 return errno;
1498         return retval;
1499 }
1500
1501 int for_each_reflog(each_ref_fn fn, void *cb_data)
1502 {
1503         return do_for_each_reflog("", fn, cb_data);
1504 }
1505
1506 int update_ref(const char *action, const char *refname,
1507                 const unsigned char *sha1, const unsigned char *oldval,
1508                 int flags, enum action_on_err onerr)
1509 {
1510         static struct ref_lock *lock;
1511         lock = lock_any_ref_for_update(refname, oldval, flags);
1512         if (!lock) {
1513                 const char *str = "Cannot lock the ref '%s'.";
1514                 switch (onerr) {
1515                 case MSG_ON_ERR: error(str, refname); break;
1516                 case DIE_ON_ERR: die(str, refname); break;
1517                 case QUIET_ON_ERR: break;
1518                 }
1519                 return 1;
1520         }
1521         if (write_ref_sha1(lock, sha1, action) < 0) {
1522                 const char *str = "Cannot update the ref '%s'.";
1523                 switch (onerr) {
1524                 case MSG_ON_ERR: error(str, refname); break;
1525                 case DIE_ON_ERR: die(str, refname); break;
1526                 case QUIET_ON_ERR: break;
1527                 }
1528                 return 1;
1529         }
1530         return 0;
1531 }
1532
1533 struct ref *find_ref_by_name(struct ref *list, const char *name)
1534 {
1535         for ( ; list; list = list->next)
1536                 if (!strcmp(list->name, name))
1537                         return list;
1538         return NULL;
1539 }