git/refs.c

   1 #include "cache.h"
   2 #include "refs.h"
   3 #include "object.h"
   4 #include "tag.h"
   5
   6 /* ISSYMREF=01 and ISPACKED=02 are public interfaces */
   7 #define REF_KNOWS_PEELED 04
   8
   9 struct ref_list {
  10         struct ref_list *next;
  11         unsigned char flag; /* ISSYMREF? ISPACKED? */
  12         unsigned char sha1[20];
  13         unsigned char peeled[20];
  14         char name[FLEX_ARRAY];
  15 };
  16
  17 static const char *parse_ref_line(char *line, unsigned char *sha1)
  18 {
  19         /*
  20          * 42: the answer to everything.
  21          *
  22          * In this case, it happens to be the answer to
  23          *  40 (length of sha1 hex representation)
  24          *  +1 (space in between hex and name)
  25          *  +1 (newline at the end of the line)
  26          */
  27         int len = strlen(line) - 42;
  28
  29         if (len <= 0)
  30                 return NULL;
  31         if (get_sha1_hex(line, sha1) < 0)
  32                 return NULL;
  33         if (!isspace(line[40]))
  34                 return NULL;
  35         line += 41;
  36         if (isspace(*line))
  37                 return NULL;
  38         if (line[len] != '\n')
  39                 return NULL;
  40         line[len] = 0;
  41
  42         return line;
  43 }
  44
  45 static struct ref_list *add_ref(const char *name, const unsigned char *sha1,
  46                                 int flag, struct ref_list *list,
  47                                 struct ref_list **new_entry)
  48 {
  49         int len;
  50         struct ref_list *entry;
  51
  52         /* Allocate it and add it in.. */
  53         len = strlen(name) + 1;
  54         entry = xmalloc(sizeof(struct ref_list) + len);
  55         hashcpy(entry->sha1, sha1);
  56         hashclr(entry->peeled);
  57         memcpy(entry->name, name, len);
  58         entry->flag = flag;
  59         entry->next = list;
  60         if (new_entry)
  61                 *new_entry = entry;
  62         return entry;
  63 }
  64
  65 /* merge sort the ref list */
  66 static struct ref_list *sort_ref_list(struct ref_list *list)
  67 {
  68         int psize, qsize, last_merge_count, cmp;
  69         struct ref_list *p, *q, *l, *e;
  70         struct ref_list *new_list = list;
  71         int k = 1;
  72         int merge_count = 0;
  73
  74         if (!list)
  75                 return list;
  76
  77         do {
  78                 last_merge_count = merge_count;
  79                 merge_count = 0;
  80
  81                 psize = 0;
  82
  83                 p = new_list;
  84                 q = new_list;
  85                 new_list = NULL;
  86                 l = NULL;
  87
  88                 while (p) {
  89                         merge_count++;
  90
  91                         while (psize < k && q->next) {
  92                                 q = q->next;
  93                                 psize++;
  94                         }
  95                         qsize = k;
  96
  97                         while ((psize > 0) || (qsize > 0 && q)) {
  98                                 if (qsize == 0 || !q) {
  99                                         e = p;
 100                                         p = p->next;
 101                                         psize--;
 102                                 } else if (psize == 0) {
 103                                         e = q;
 104                                         q = q->next;
 105                                         qsize--;
 106                                 } else {
 107                                         cmp = strcmp(q->name, p->name);
 108                                         if (cmp < 0) {
 109                                                 e = q;
 110                                                 q = q->next;
 111                                                 qsize--;
 112                                         } else if (cmp > 0) {
 113                                                 e = p;
 114                                                 p = p->next;
 115                                                 psize--;
 116                                         } else {
 117                                                 if (hashcmp(q->sha1, p->sha1))
 118                                                         die("Duplicated ref, and SHA1s don't match: %s",
 119                                                             q->name);
 120                                                 warning("Duplicated ref: %s", q->name);
 121                                                 e = q;
 122                                                 q = q->next;
 123                                                 qsize--;
 124                                                 free(e);
 125                                                 e = p;
 126                                                 p = p->next;
 127                                                 psize--;
 128                                         }
 129                                 }
 130
 131                                 e->next = NULL;
 132
 133                                 if (l)
 134                                         l->next = e;
 135                                 if (!new_list)
 136                                         new_list = e;
 137                                 l = e;
 138                         }
 139
 140                         p = q;
 141                 };
 142
 143                 k = k * 2;
 144         } while ((last_merge_count != merge_count) || (last_merge_count != 1));
 145
 146         return new_list;
 147 }
 148
 149 /*
 150  * Future: need to be in "struct repository"
 151  * when doing a full libification.
 152  */
 153 static struct cached_refs {
 154         char did_loose;
 155         char did_packed;
 156         struct ref_list *loose;
 157         struct ref_list *packed;
 158 } cached_refs;
 159
 160 static void free_ref_list(struct ref_list *list)
 161 {
 162         struct ref_list *next;
 163         for ( ; list; list = next) {
 164                 next = list->next;
 165                 free(list);
 166         }
 167 }
 168
 169 static void invalidate_cached_refs(void)
 170 {
 171         struct cached_refs *ca = &cached_refs;
 172
 173         if (ca->did_loose && ca->loose)
 174                 free_ref_list(ca->loose);
 175         if (ca->did_packed && ca->packed)
 176                 free_ref_list(ca->packed);
 177         ca->loose = ca->packed = NULL;
 178         ca->did_loose = ca->did_packed = 0;
 179 }
 180
 181 static void read_packed_refs(FILE *f, struct cached_refs *cached_refs)
 182 {
 183         struct ref_list *list = NULL;
 184         struct ref_list *last = NULL;
 185         char refline[PATH_MAX];
 186         int flag = REF_ISPACKED;
 187
 188         while (fgets(refline, sizeof(refline), f)) {
 189                 unsigned char sha1[20];
 190                 const char *name;
 191                 static const char header[] = "# pack-refs with:";
 192
 193                 if (!strncmp(refline, header, sizeof(header)-1)) {
 194                         const char *traits = refline + sizeof(header) - 1;
 195                         if (strstr(traits, " peeled "))
 196                                 flag |= REF_KNOWS_PEELED;
 197                         /* perhaps other traits later as well */
 198                         continue;
 199                 }
 200
 201                 name = parse_ref_line(refline, sha1);
 202                 if (name) {
 203                         list = add_ref(name, sha1, flag, list, &last);
 204                         continue;
 205                 }
 206                 if (last &&
 207                     refline[0] == '^' &&
 208                     strlen(refline) == 42 &&
 209                     refline[41] == '\n' &&
 210                     !get_sha1_hex(refline + 1, sha1))
 211                         hashcpy(last->peeled, sha1);
 212         }
 213         cached_refs->packed = sort_ref_list(list);
 214 }
 215
 216 static struct ref_list *get_packed_refs(void)
 217 {
 218         if (!cached_refs.did_packed) {
 219                 FILE *f = fopen(git_path("packed-refs"), "r");
 220                 cached_refs.packed = NULL;
 221                 if (f) {
 222                         read_packed_refs(f, &cached_refs);
 223                         fclose(f);
 224                 }
 225                 cached_refs.did_packed = 1;
 226         }
 227         return cached_refs.packed;
 228 }
 229
 230 static struct ref_list *get_ref_dir(const char *base, struct ref_list *list)
 231 {
 232         DIR *dir = opendir(git_path("%s", base));
 233
 234         if (dir) {
 235                 struct dirent *de;
 236                 int baselen = strlen(base);
 237                 char *ref = xmalloc(baselen + 257);
 238
 239                 memcpy(ref, base, baselen);
 240                 if (baselen && base[baselen-1] != '/')
 241                         ref[baselen++] = '/';
 242
 243                 while ((de = readdir(dir)) != NULL) {
 244                         unsigned char sha1[20];
 245                         struct stat st;
 246                         int flag;
 247                         int namelen;
 248
 249                         if (de->d_name[0] == '.')
 250                                 continue;
 251                         namelen = strlen(de->d_name);
 252                         if (namelen > 255)
 253                                 continue;
 254                         if (has_extension(de->d_name, ".lock"))
 255                                 continue;
 256                         memcpy(ref + baselen, de->d_name, namelen+1);
 257                         if (stat(git_path("%s", ref), &st) < 0)
 258                                 continue;
 259                         if (S_ISDIR(st.st_mode)) {
 260                                 list = get_ref_dir(ref, list);
 261                                 continue;
 262                         }
 263                         if (!resolve_ref(ref, sha1, 1, &flag)) {
 264                                 error("%s points nowhere!", ref);
 265                                 continue;
 266                         }
 267                         list = add_ref(ref, sha1, flag, list, NULL);
 268                 }
 269                 free(ref);
 270                 closedir(dir);
 271         }
 272         return sort_ref_list(list);
 273 }
 274
 275 static struct ref_list *get_loose_refs(void)
 276 {
 277         if (!cached_refs.did_loose) {
 278                 cached_refs.loose = get_ref_dir("refs", NULL);
 279                 cached_refs.did_loose = 1;
 280         }
 281         return cached_refs.loose;
 282 }
 283
 284 /* We allow "recursive" symbolic refs. Only within reason, though */
 285 #define MAXDEPTH 5
 286 #define MAXREFLEN (1024)
 287
 288 static int resolve_gitlink_packed_ref(char *name, int pathlen, const char *refname, unsigned char *result)
 289 {
 290         FILE *f;
 291         struct cached_refs refs;
 292         struct ref_list *ref;
 293         int retval;
 294
 295         strcpy(name + pathlen, "packed-refs");
 296         f = fopen(name, "r");
 297         if (!f)
 298                 return -1;
 299         read_packed_refs(f, &refs);
 300         fclose(f);
 301         ref = refs.packed;
 302         retval = -1;
 303         while (ref) {
 304                 if (!strcmp(ref->name, refname)) {
 305                         retval = 0;
 306                         memcpy(result, ref->sha1, 20);
 307                         break;
 308                 }
 309                 ref = ref->next;
 310         }
 311         free_ref_list(refs.packed);
 312         return retval;
 313 }
 314
 315 static int resolve_gitlink_ref_recursive(char *name, int pathlen, const char *refname, unsigned char *result, int recursion)
 316 {
 317         int fd, len = strlen(refname);
 318         char buffer[128], *p;
 319
 320         if (recursion > MAXDEPTH || len > MAXREFLEN)
 321                 return -1;
 322         memcpy(name + pathlen, refname, len+1);
 323         fd = open(name, O_RDONLY);
 324         if (fd < 0)
 325                 return resolve_gitlink_packed_ref(name, pathlen, refname, result);
 326
 327         len = read(fd, buffer, sizeof(buffer)-1);
 328         close(fd);
 329         if (len < 0)
 330                 return -1;
 331         while (len && isspace(buffer[len-1]))
 332                 len--;
 333         buffer[len] = 0;
 334
 335         /* Was it a detached head or an old-fashioned symlink? */
 336         if (!get_sha1_hex(buffer, result))
 337                 return 0;
 338
 339         /* Symref? */
 340         if (strncmp(buffer, "ref:", 4))
 341                 return -1;
 342         p = buffer + 4;
 343         while (isspace(*p))
 344                 p++;
 345
 346         return resolve_gitlink_ref_recursive(name, pathlen, p, result, recursion+1);
 347 }
 348
 349 int resolve_gitlink_ref(const char *path, const char *refname, unsigned char *result)
 350 {
 351         int len = strlen(path), retval;
 352         char *gitdir;
 353
 354         while (len && path[len-1] == '/')
 355                 len--;
 356         if (!len)
 357                 return -1;
 358         gitdir = xmalloc(len + MAXREFLEN + 8);
 359         memcpy(gitdir, path, len);
 360         memcpy(gitdir + len, "/.git/", 7);
 361
 362         retval = resolve_gitlink_ref_recursive(gitdir, len+6, refname, result, 0);
 363         free(gitdir);
 364         return retval;
 365 }
 366
 367 const char *resolve_ref(const char *ref, unsigned char *sha1, int reading, int *flag)
 368 {
 369         int depth = MAXDEPTH, len;
 370         char buffer[256];
 371         static char ref_buffer[256];
 372
 373         if (flag)
 374                 *flag = 0;
 375
 376         for (;;) {
 377                 const char *path = git_path("%s", ref);
 378                 struct stat st;
 379                 char *buf;
 380                 int fd;
 381
 382                 if (--depth < 0)
 383                         return NULL;
 384
 385                 /* Special case: non-existing file.
 386                  * Not having the refs/heads/new-branch is OK
 387                  * if we are writing into it, so is .git/HEAD
 388                  * that points at refs/heads/master still to be
 389                  * born.  It is NOT OK if we are resolving for
 390                  * reading.
 391                  */
 392                 if (lstat(path, &st) < 0) {
 393                         struct ref_list *list = get_packed_refs();
 394                         while (list) {
 395                                 if (!strcmp(ref, list->name)) {
 396                                         hashcpy(sha1, list->sha1);
 397                                         if (flag)
 398                                                 *flag |= REF_ISPACKED;
 399                                         return ref;
 400                                 }
 401                                 list = list->next;
 402                         }
 403                         if (reading || errno != ENOENT)
 404                                 return NULL;
 405                         hashclr(sha1);
 406                         return ref;
 407                 }
 408
 409                 /* Follow "normalized" - ie "refs/.." symlinks by hand */
 410                 if (S_ISLNK(st.st_mode)) {
 411                         len = readlink(path, buffer, sizeof(buffer)-1);
 412                         if (len >= 5 && !memcmp("refs/", buffer, 5)) {
 413                                 buffer[len] = 0;
 414                                 strcpy(ref_buffer, buffer);
 415                                 ref = ref_buffer;
 416                                 if (flag)
 417                                         *flag |= REF_ISSYMREF;
 418                                 continue;
 419                         }
 420                 }
 421
 422                 /* Is it a directory? */
 423                 if (S_ISDIR(st.st_mode)) {
 424                         errno = EISDIR;
 425                         return NULL;
 426                 }
 427
 428                 /*
 429                  * Anything else, just open it and try to use it as
 430                  * a ref
 431                  */
 432                 fd = open(path, O_RDONLY);
 433                 if (fd < 0)
 434                         return NULL;
 435                 len = read_in_full(fd, buffer, sizeof(buffer)-1);
 436                 close(fd);
 437
 438                 /*
 439                  * Is it a symbolic ref?
 440                  */
 441                 if (len < 4 || memcmp("ref:", buffer, 4))
 442                         break;
 443                 buf = buffer + 4;
 444                 len -= 4;
 445                 while (len && isspace(*buf))
 446                         buf++, len--;
 447                 while (len && isspace(buf[len-1]))
 448                         len--;
 449                 buf[len] = 0;
 450                 memcpy(ref_buffer, buf, len + 1);
 451                 ref = ref_buffer;
 452                 if (flag)
 453                         *flag |= REF_ISSYMREF;
 454         }
 455         if (len < 40 || get_sha1_hex(buffer, sha1))
 456                 return NULL;
 457         return ref;
 458 }
 459
 460 int read_ref(const char *ref, unsigned char *sha1)
 461 {
 462         if (resolve_ref(ref, sha1, 1, NULL))
 463                 return 0;
 464         return -1;
 465 }
 466
 467 static int do_one_ref(const char *base, each_ref_fn fn, int trim,
 468                       void *cb_data, struct ref_list *entry)
 469 {
 470         if (strncmp(base, entry->name, trim))
 471                 return 0;
 472         if (is_null_sha1(entry->sha1))
 473                 return 0;
 474         if (!has_sha1_file(entry->sha1)) {
 475                 error("%s does not point to a valid object!", entry->name);
 476                 return 0;
 477         }
 478         return fn(entry->name + trim, entry->sha1, entry->flag, cb_data);
 479 }
 480
 481 int peel_ref(const char *ref, unsigned char *sha1)
 482 {
 483         int flag;
 484         unsigned char base[20];
 485         struct object *o;
 486
 487         if (!resolve_ref(ref, base, 1, &flag))
 488                 return -1;
 489
 490         if ((flag & REF_ISPACKED)) {
 491                 struct ref_list *list = get_packed_refs();
 492
 493                 while (list) {
 494                         if (!strcmp(list->name, ref)) {
 495                                 if (list->flag & REF_KNOWS_PEELED) {
 496                                         hashcpy(sha1, list->peeled);
 497                                         return 0;
 498                                 }
 499                                 /* older pack-refs did not leave peeled ones */
 500                                 break;
 501                         }
 502                         list = list->next;
 503                 }
 504         }
 505
 506         /* fallback - callers should not call this for unpacked refs */
 507         o = parse_object(base);
 508         if (o->type == OBJ_TAG) {
 509                 o = deref_tag(o, ref, 0);
 510                 if (o) {
 511                         hashcpy(sha1, o->sha1);
 512                         return 0;
 513                 }
 514         }
 515         return -1;
 516 }
 517
 518 static int do_for_each_ref(const char *base, each_ref_fn fn, int trim,
 519                            void *cb_data)
 520 {
 521         int retval;
 522         struct ref_list *packed = get_packed_refs();
 523         struct ref_list *loose = get_loose_refs();
 524
 525         while (packed && loose) {
 526                 struct ref_list *entry;
 527                 int cmp = strcmp(packed->name, loose->name);
 528                 if (!cmp) {
 529                         packed = packed->next;
 530                         continue;
 531                 }
 532                 if (cmp > 0) {
 533                         entry = loose;
 534                         loose = loose->next;
 535                 } else {
 536                         entry = packed;
 537                         packed = packed->next;
 538                 }
 539                 retval = do_one_ref(base, fn, trim, cb_data, entry);
 540                 if (retval)
 541                         return retval;
 542         }
 543
 544         for (packed = packed ? packed : loose; packed; packed = packed->next) {
 545                 retval = do_one_ref(base, fn, trim, cb_data, packed);
 546                 if (retval)
 547                         return retval;
 548         }
 549         return 0;
 550 }
 551
 552 int head_ref(each_ref_fn fn, void *cb_data)
 553 {
 554         unsigned char sha1[20];
 555         int flag;
 556
 557         if (resolve_ref("HEAD", sha1, 1, &flag))
 558                 return fn("HEAD", sha1, flag, cb_data);
 559         return 0;
 560 }
 561
 562 int for_each_ref(each_ref_fn fn, void *cb_data)
 563 {
 564         return do_for_each_ref("refs/", fn, 0, cb_data);
 565 }
 566
 567 int for_each_tag_ref(each_ref_fn fn, void *cb_data)
 568 {
 569         return do_for_each_ref("refs/tags/", fn, 10, cb_data);
 570 }
 571
 572 int for_each_branch_ref(each_ref_fn fn, void *cb_data)
 573 {
 574         return do_for_each_ref("refs/heads/", fn, 11, cb_data);
 575 }
 576
 577 int for_each_remote_ref(each_ref_fn fn, void *cb_data)
 578 {
 579         return do_for_each_ref("refs/remotes/", fn, 13, cb_data);
 580 }
 581
 582 /* NEEDSWORK: This is only used by ssh-upload and it should go; the
 583  * caller should do resolve_ref or read_ref like everybody else.  Or
 584  * maybe everybody else should use get_ref_sha1() instead of doing
 585  * read_ref().
 586  */
 587 int get_ref_sha1(const char *ref, unsigned char *sha1)
 588 {
 589         if (check_ref_format(ref))
 590                 return -1;
 591         return read_ref(mkpath("refs/%s", ref), sha1);
 592 }
 593
 594 /*
 595  * Make sure "ref" is something reasonable to have under ".git/refs/";
 596  * We do not like it if:
 597  *
 598  * - any path component of it begins with ".", or
 599  * - it has double dots "..", or
 600  * - it has ASCII control character, "~", "^", ":" or SP, anywhere, or
 601  * - it ends with a "/".
 602  */
 603
 604 static inline int bad_ref_char(int ch)
 605 {
 606         if (((unsigned) ch) <= ' ' ||
 607             ch == '~' || ch == '^' || ch == ':')
 608                 return 1;
 609         /* 2.13 Pattern Matching Notation */
 610         if (ch == '?' || ch == '[') /* Unsupported */
 611                 return 1;
 612         if (ch == '*') /* Supported at the end */
 613                 return 2;
 614         return 0;
 615 }
 616
 617 int check_ref_format(const char *ref)
 618 {
 619         int ch, level, bad_type;
 620         const char *cp = ref;
 621
 622         level = 0;
 623         while (1) {
 624                 while ((ch = *cp++) == '/')
 625                         ; /* tolerate duplicated slashes */
 626                 if (!ch)
 627                         return -1; /* should not end with slashes */
 628
 629                 /* we are at the beginning of the path component */
 630                 if (ch == '.')
 631                         return -1;
 632                 bad_type = bad_ref_char(ch);
 633                 if (bad_type) {
 634                         return (bad_type == 2 && !*cp) ? -3 : -1;
 635                 }
 636
 637                 /* scan the rest of the path component */
 638                 while ((ch = *cp++) != 0) {
 639                         bad_type = bad_ref_char(ch);
 640                         if (bad_type) {
 641                                 return (bad_type == 2 && !*cp) ? -3 : -1;
 642                         }
 643                         if (ch == '/')
 644                                 break;
 645                         if (ch == '.' && *cp == '.')
 646                                 return -1;
 647                 }
 648                 level++;
 649                 if (!ch) {
 650                         if (level < 2)
 651                                 return -2; /* at least of form "heads/blah" */
 652                         return 0;
 653                 }
 654         }
 655 }
 656
 657 static struct ref_lock *verify_lock(struct ref_lock *lock,
 658         const unsigned char *old_sha1, int mustexist)
 659 {
 660         if (!resolve_ref(lock->ref_name, lock->old_sha1, mustexist, NULL)) {
 661                 error("Can't verify ref %s", lock->ref_name);
 662                 unlock_ref(lock);
 663                 return NULL;
 664         }
 665         if (hashcmp(lock->old_sha1, old_sha1)) {
 666                 error("Ref %s is at %s but expected %s", lock->ref_name,
 667                         sha1_to_hex(lock->old_sha1), sha1_to_hex(old_sha1));
 668                 unlock_ref(lock);
 669                 return NULL;
 670         }
 671         return lock;
 672 }
 673
 674 static int remove_empty_dir_recursive(char *path, int len)
 675 {
 676         DIR *dir = opendir(path);
 677         struct dirent *e;
 678         int ret = 0;
 679
 680         if (!dir)
 681                 return -1;
 682         if (path[len-1] != '/')
 683                 path[len++] = '/';
 684         while ((e = readdir(dir)) != NULL) {
 685                 struct stat st;
 686                 int namlen;
 687                 if ((e->d_name[0] == '.') &&
 688                     ((e->d_name[1] == 0) ||
 689                      ((e->d_name[1] == '.') && e->d_name[2] == 0)))
 690                         continue; /* "." and ".." */
 691
 692                 namlen = strlen(e->d_name);
 693                 if ((len + namlen < PATH_MAX) &&
 694                     strcpy(path + len, e->d_name) &&
 695                     !lstat(path, &st) &&
 696                     S_ISDIR(st.st_mode) &&
 697                     !remove_empty_dir_recursive(path, len + namlen))
 698                         continue; /* happy */
 699
 700                 /* path too long, stat fails, or non-directory still exists */
 701                 ret = -1;
 702                 break;
 703         }
 704         closedir(dir);
 705         if (!ret) {
 706                 path[len] = 0;
 707                 ret = rmdir(path);
 708         }
 709         return ret;
 710 }
 711
 712 static int remove_empty_directories(char *file)
 713 {
 714         /* we want to create a file but there is a directory there;
 715          * if that is an empty directory (or a directory that contains
 716          * only empty directories), remove them.
 717          */
 718         char path[PATH_MAX];
 719         int len = strlen(file);
 720
 721         if (len >= PATH_MAX) /* path too long ;-) */
 722                 return -1;
 723         strcpy(path, file);
 724         return remove_empty_dir_recursive(path, len);
 725 }
 726
 727 static int is_refname_available(const char *ref, const char *oldref,
 728                                 struct ref_list *list, int quiet)
 729 {
 730         int namlen = strlen(ref); /* e.g. 'foo/bar' */
 731         while (list) {
 732                 /* list->name could be 'foo' or 'foo/bar/baz' */
 733                 if (!oldref || strcmp(oldref, list->name)) {
 734                         int len = strlen(list->name);
 735                         int cmplen = (namlen < len) ? namlen : len;
 736                         const char *lead = (namlen < len) ? list->name : ref;
 737                         if (!strncmp(ref, list->name, cmplen) &&
 738                             lead[cmplen] == '/') {
 739                                 if (!quiet)
 740                                         error("'%s' exists; cannot create '%s'",
 741                                               list->name, ref);
 742                                 return 0;
 743                         }
 744                 }
 745                 list = list->next;
 746         }
 747         return 1;
 748 }
 749
 750 static struct ref_lock *lock_ref_sha1_basic(const char *ref, const unsigned char *old_sha1, int flags, int *type_p)
 751 {
 752         char *ref_file;
 753         const char *orig_ref = ref;
 754         struct ref_lock *lock;
 755         struct stat st;
 756         int last_errno = 0;
 757         int type;
 758         int mustexist = (old_sha1 && !is_null_sha1(old_sha1));
 759
 760         lock = xcalloc(1, sizeof(struct ref_lock));
 761         lock->lock_fd = -1;
 762
 763         ref = resolve_ref(ref, lock->old_sha1, mustexist, &type);
 764         if (!ref && errno == EISDIR) {
 765                 /* we are trying to lock foo but we used to
 766                  * have foo/bar which now does not exist;
 767                  * it is normal for the empty directory 'foo'
 768                  * to remain.
 769                  */
 770                 ref_file = git_path("%s", orig_ref);
 771                 if (remove_empty_directories(ref_file)) {
 772                         last_errno = errno;
 773                         error("there are still refs under '%s'", orig_ref);
 774                         goto error_return;
 775                 }
 776                 ref = resolve_ref(orig_ref, lock->old_sha1, mustexist, &type);
 777         }
 778         if (type_p)
 779             *type_p = type;
 780         if (!ref) {
 781                 last_errno = errno;
 782                 error("unable to resolve reference %s: %s",
 783                         orig_ref, strerror(errno));
 784                 goto error_return;
 785         }
 786         /* When the ref did not exist and we are creating it,
 787          * make sure there is no existing ref that is packed
 788          * whose name begins with our refname, nor a ref whose
 789          * name is a proper prefix of our refname.
 790          */
 791         if (is_null_sha1(lock->old_sha1) &&
 792             !is_refname_available(ref, NULL, get_packed_refs(), 0))
 793                 goto error_return;
 794
 795         lock->lk = xcalloc(1, sizeof(struct lock_file));
 796
 797         if (flags & REF_NODEREF)
 798                 ref = orig_ref;
 799         lock->ref_name = xstrdup(ref);
 800         lock->orig_ref_name = xstrdup(orig_ref);
 801         ref_file = git_path("%s", ref);
 802         if (lstat(ref_file, &st) && errno == ENOENT)
 803                 lock->force_write = 1;
 804         if ((flags & REF_NODEREF) && (type & REF_ISSYMREF))
 805                 lock->force_write = 1;
 806
 807         if (safe_create_leading_directories(ref_file)) {
 808                 last_errno = errno;
 809                 error("unable to create directory for %s", ref_file);
 810                 goto error_return;
 811         }
 812         lock->lock_fd = hold_lock_file_for_update(lock->lk, ref_file, 1);
 813
 814         return old_sha1 ? verify_lock(lock, old_sha1, mustexist) : lock;
 815
 816  error_return:
 817         unlock_ref(lock);
 818         errno = last_errno;
 819         return NULL;
 820 }
 821
 822 struct ref_lock *lock_ref_sha1(const char *ref, const unsigned char *old_sha1)
 823 {
 824         char refpath[PATH_MAX];
 825         if (check_ref_format(ref))
 826                 return NULL;
 827         strcpy(refpath, mkpath("refs/%s", ref));
 828         return lock_ref_sha1_basic(refpath, old_sha1, 0, NULL);
 829 }
 830
 831 struct ref_lock *lock_any_ref_for_update(const char *ref, const unsigned char *old_sha1, int flags)
 832 {
 833         if (check_ref_format(ref) == -1)
 834                 return NULL;
 835         return lock_ref_sha1_basic(ref, old_sha1, flags, NULL);
 836 }
 837
 838 static struct lock_file packlock;
 839
 840 static int repack_without_ref(const char *refname)
 841 {
 842         struct ref_list *list, *packed_ref_list;
 843         int fd;
 844         int found = 0;
 845
 846         packed_ref_list = get_packed_refs();
 847         for (list = packed_ref_list; list; list = list->next) {
 848                 if (!strcmp(refname, list->name)) {
 849                         found = 1;
 850                         break;
 851                 }
 852         }
 853         if (!found)
 854                 return 0;
 855         fd = hold_lock_file_for_update(&packlock, git_path("packed-refs"), 0);
 856         if (fd < 0)
 857                 return error("cannot delete '%s' from packed refs", refname);
 858
 859         for (list = packed_ref_list; list; list = list->next) {
 860                 char line[PATH_MAX + 100];
 861                 int len;
 862
 863                 if (!strcmp(refname, list->name))
 864                         continue;
 865                 len = snprintf(line, sizeof(line), "%s %s\n",
 866                                sha1_to_hex(list->sha1), list->name);
 867                 /* this should not happen but just being defensive */
 868                 if (len > sizeof(line))
 869                         die("too long a refname '%s'", list->name);
 870                 write_or_die(fd, line, len);
 871         }
 872         return commit_lock_file(&packlock);
 873 }
 874
 875 int delete_ref(const char *refname, const unsigned char *sha1)
 876 {
 877         struct ref_lock *lock;
 878         int err, i, ret = 0, flag = 0;
 879
 880         lock = lock_ref_sha1_basic(refname, sha1, 0, &flag);
 881         if (!lock)
 882                 return 1;
 883         if (!(flag & REF_ISPACKED)) {
 884                 /* loose */
 885                 i = strlen(lock->lk->filename) - 5; /* .lock */
 886                 lock->lk->filename[i] = 0;
 887                 err = unlink(lock->lk->filename);
 888                 if (err) {
 889                         ret = 1;
 890                         error("unlink(%s) failed: %s",
 891                               lock->lk->filename, strerror(errno));
 892                 }
 893                 lock->lk->filename[i] = '.';
 894         }
 895         /* removing the loose one could have resurrected an earlier
 896          * packed one.  Also, if it was not loose we need to repack
 897          * without it.
 898          */
 899         ret |= repack_without_ref(refname);
 900
 901         err = unlink(git_path("logs/%s", lock->ref_name));
 902         if (err && errno != ENOENT)
 903                 fprintf(stderr, "warning: unlink(%s) failed: %s",
 904                         git_path("logs/%s", lock->ref_name), strerror(errno));
 905         invalidate_cached_refs();
 906         unlock_ref(lock);
 907         return ret;
 908 }
 909
 910 int rename_ref(const char *oldref, const char *newref, const char *logmsg)
 911 {
 912         static const char renamed_ref[] = "RENAMED-REF";
 913         unsigned char sha1[20], orig_sha1[20];
 914         int flag = 0, logmoved = 0;
 915         struct ref_lock *lock;
 916         struct stat loginfo;
 917         int log = !lstat(git_path("logs/%s", oldref), &loginfo);
 918
 919         if (S_ISLNK(loginfo.st_mode))
 920                 return error("reflog for %s is a symlink", oldref);
 921
 922         if (!resolve_ref(oldref, orig_sha1, 1, &flag))
 923                 return error("refname %s not found", oldref);
 924
 925         if (!is_refname_available(newref, oldref, get_packed_refs(), 0))
 926                 return 1;
 927
 928         if (!is_refname_available(newref, oldref, get_loose_refs(), 0))
 929                 return 1;
 930
 931         lock = lock_ref_sha1_basic(renamed_ref, NULL, 0, NULL);
 932         if (!lock)
 933                 return error("unable to lock %s", renamed_ref);
 934         lock->force_write = 1;
 935         if (write_ref_sha1(lock, orig_sha1, logmsg))
 936                 return error("unable to save current sha1 in %s", renamed_ref);
 937
 938         if (log && rename(git_path("logs/%s", oldref), git_path("tmp-renamed-log")))
 939                 return error("unable to move logfile logs/%s to tmp-renamed-log: %s",
 940                         oldref, strerror(errno));
 941
 942         if (delete_ref(oldref, orig_sha1)) {
 943                 error("unable to delete old %s", oldref);
 944                 goto rollback;
 945         }
 946
 947         if (resolve_ref(newref, sha1, 1, &flag) && delete_ref(newref, sha1)) {
 948                 if (errno==EISDIR) {
 949                         if (remove_empty_directories(git_path("%s", newref))) {
 950                                 error("Directory not empty: %s", newref);
 951                                 goto rollback;
 952                         }
 953                 } else {
 954                         error("unable to delete existing %s", newref);
 955                         goto rollback;
 956                 }
 957         }
 958
 959         if (log && safe_create_leading_directories(git_path("logs/%s", newref))) {
 960                 error("unable to create directory for %s", newref);
 961                 goto rollback;
 962         }
 963
 964  retry:
 965         if (log && rename(git_path("tmp-renamed-log"), git_path("logs/%s", newref))) {
 966 #ifdef __MINGW32__
 967                 if (errno == EEXIST) {
 968                         struct stat st;
 969                         if (stat(git_path("logs/%s", newref), &st) == 0 && S_ISDIR(st.st_mode))
 970                                 errno = EISDIR;
 971                         else
 972                                 errno = EEXIST;
 973                 }
 974 #endif
 975                 if (errno==EISDIR || errno==ENOTDIR) {
 976                         /*
 977                          * rename(a, b) when b is an existing
 978                          * directory ought to result in ISDIR, but
 979                          * Solaris 5.8 gives ENOTDIR.  Sheesh.
 980                          */
 981                         if (remove_empty_directories(git_path("logs/%s", newref))) {
 982                                 error("Directory not empty: logs/%s", newref);
 983                                 goto rollback;
 984                         }
 985                         goto retry;
 986                 } else {
 987                         error("unable to move logfile tmp-renamed-log to logs/%s: %s",
 988                                 newref, strerror(errno));
 989                         goto rollback;
 990                 }
 991         }
 992         logmoved = log;
 993
 994         lock = lock_ref_sha1_basic(newref, NULL, 0, NULL);
 995         if (!lock) {
 996                 error("unable to lock %s for update", newref);
 997                 goto rollback;
 998         }
 999
1000         lock->force_write = 1;
1001         hashcpy(lock->old_sha1, orig_sha1);
1002         if (write_ref_sha1(lock, orig_sha1, logmsg)) {
1003                 error("unable to write current sha1 into %s", newref);
1004                 goto rollback;
1005         }
1006
1007         return 0;
1008
1009  rollback:
1010         lock = lock_ref_sha1_basic(oldref, NULL, 0, NULL);
1011         if (!lock) {
1012                 error("unable to lock %s for rollback", oldref);
1013                 goto rollbacklog;
1014         }
1015
1016         lock->force_write = 1;
1017         flag = log_all_ref_updates;
1018         log_all_ref_updates = 0;
1019         if (write_ref_sha1(lock, orig_sha1, NULL))
1020                 error("unable to write current sha1 into %s", oldref);
1021         log_all_ref_updates = flag;
1022
1023  rollbacklog:
1024         if (logmoved && rename(git_path("logs/%s", newref), git_path("logs/%s", oldref)))
1025                 error("unable to restore logfile %s from %s: %s",
1026                         oldref, newref, strerror(errno));
1027         if (!logmoved && log &&
1028             rename(git_path("tmp-renamed-log"), git_path("logs/%s", oldref)))
1029                 error("unable to restore logfile %s from tmp-renamed-log: %s",
1030                         oldref, strerror(errno));
1031
1032         return 1;
1033 }
1034
1035 void unlock_ref(struct ref_lock *lock)
1036 {
1037         if (lock->lock_fd >= 0) {
1038                 close(lock->lock_fd);
1039                 /* Do not free lock->lk -- atexit() still looks at them */
1040                 if (lock->lk)
1041                         rollback_lock_file(lock->lk);
1042         }
1043         free(lock->ref_name);
1044         free(lock->orig_ref_name);
1045         free(lock);
1046 }
1047
1048 static int log_ref_write(const char *ref_name, const unsigned char *old_sha1,
1049                          const unsigned char *new_sha1, const char *msg)
1050 {
1051         int logfd, written, oflags = O_APPEND | O_WRONLY;
1052         unsigned maxlen, len;
1053         int msglen;
1054         char *log_file, *logrec;
1055         const char *committer;
1056
1057         if (log_all_ref_updates < 0)
1058                 log_all_ref_updates = !is_bare_repository();
1059
1060         log_file = git_path("logs/%s", ref_name);
1061
1062         if (log_all_ref_updates &&
1063             (!prefixcmp(ref_name, "refs/heads/") ||
1064              !prefixcmp(ref_name, "refs/remotes/") ||
1065              !strcmp(ref_name, "HEAD"))) {
1066                 if (safe_create_leading_directories(log_file) < 0)
1067                         return error("unable to create directory for %s",
1068                                      log_file);
1069                 oflags |= O_CREAT;
1070         }
1071
1072         logfd = open(log_file, oflags, 0666);
1073         if (logfd < 0) {
1074                 if (!(oflags & O_CREAT) && errno == ENOENT)
1075                         return 0;
1076
1077 #ifdef __MINGW32__
1078                 if ((oflags & O_CREAT) && errno == EACCES) {
1079                         struct stat st;
1080                         if (stat(log_file, &st) == 0 && S_ISDIR(st.st_mode))
1081                                 errno = EISDIR;
1082                         else
1083                                 errno = EACCES;
1084                 }
1085 #endif
1086                 if ((oflags & O_CREAT) && errno == EISDIR) {
1087                         if (remove_empty_directories(log_file)) {
1088                                 return error("There are still logs under '%s'",
1089                                              log_file);
1090                         }
1091                         logfd = open(log_file, oflags, 0666);
1092                 }
1093
1094                 if (logfd < 0)
1095                         return error("Unable to append to %s: %s",
1096                                      log_file, strerror(errno));
1097         }
1098
1099         adjust_shared_perm(log_file);
1100
1101         msglen = 0;
1102         if (msg) {
1103                 /* clean up the message and make sure it is a single line */
1104                 for ( ; *msg; msg++)
1105                         if (!isspace(*msg))
1106                                 break;
1107                 if (*msg) {
1108                         const char *ep = strchr(msg, '\n');
1109                         if (ep)
1110                                 msglen = ep - msg;
1111                         else
1112                                 msglen = strlen(msg);
1113                 }
1114         }
1115
1116         committer = git_committer_info(-1);
1117         maxlen = strlen(committer) + msglen + 100;
1118         logrec = xmalloc(maxlen);
1119         len = sprintf(logrec, "%s %s %s\n",
1120                       sha1_to_hex(old_sha1),
1121                       sha1_to_hex(new_sha1),
1122                       committer);
1123         if (msglen)
1124                 len += sprintf(logrec + len - 1, "\t%.*s\n", msglen, msg) - 1;
1125         written = len <= maxlen ? write_in_full(logfd, logrec, len) : -1;
1126         free(logrec);
1127         if (close(logfd) != 0 || written != len)
1128                 return error("Unable to append to %s", log_file);
1129         return 0;
1130 }
1131
1132 int write_ref_sha1(struct ref_lock *lock,
1133         const unsigned char *sha1, const char *logmsg)
1134 {
1135         static char term = '\n';
1136
1137         if (!lock)
1138                 return -1;
1139         if (!lock->force_write && !hashcmp(lock->old_sha1, sha1)) {
1140                 unlock_ref(lock);
1141                 return 0;
1142         }
1143         if (write_in_full(lock->lock_fd, sha1_to_hex(sha1), 40) != 40 ||
1144             write_in_full(lock->lock_fd, &term, 1) != 1
1145                 || close(lock->lock_fd) < 0) {
1146                 error("Couldn't write %s", lock->lk->filename);
1147                 unlock_ref(lock);
1148                 return -1;
1149         }
1150         invalidate_cached_refs();
1151         if (log_ref_write(lock->ref_name, lock->old_sha1, sha1, logmsg) < 0 ||
1152             (strcmp(lock->ref_name, lock->orig_ref_name) &&
1153              log_ref_write(lock->orig_ref_name, lock->old_sha1, sha1, logmsg) < 0)) {
1154                 unlock_ref(lock);
1155                 return -1;
1156         }
1157         if (strcmp(lock->orig_ref_name, "HEAD") != 0) {
1158                 /*
1159                  * Special hack: If a branch is updated directly and HEAD
1160                  * points to it (may happen on the remote side of a push
1161                  * for example) then logically the HEAD reflog should be
1162                  * updated too.
1163                  * A generic solution implies reverse symref information,
1164                  * but finding all symrefs pointing to the given branch
1165                  * would be rather costly for this rare event (the direct
1166                  * update of a branch) to be worth it.  So let's cheat and
1167                  * check with HEAD only which should cover 99% of all usage
1168                  * scenarios (even 100% of the default ones).
1169                  */
1170                 unsigned char head_sha1[20];
1171                 int head_flag;
1172                 const char *head_ref;
1173                 head_ref = resolve_ref("HEAD", head_sha1, 1, &head_flag);
1174                 if (head_ref && (head_flag & REF_ISSYMREF) &&
1175                     !strcmp(head_ref, lock->ref_name))
1176                         log_ref_write("HEAD", lock->old_sha1, sha1, logmsg);
1177         }
1178         if (commit_lock_file(lock->lk)) {
1179                 error("Couldn't set %s", lock->ref_name);
1180                 unlock_ref(lock);
1181                 return -1;
1182         }
1183         lock->lock_fd = -1;
1184         unlock_ref(lock);
1185         return 0;
1186 }
1187
1188 int create_symref(const char *ref_target, const char *refs_heads_master,
1189                   const char *logmsg)
1190 {
1191         const char *lockpath;
1192         char ref[1000];
1193         int fd, len, written;
1194         char *git_HEAD = xstrdup(git_path("%s", ref_target));
1195         unsigned char old_sha1[20], new_sha1[20];
1196
1197         if (logmsg && read_ref(ref_target, old_sha1))
1198                 hashclr(old_sha1);
1199
1200         if (safe_create_leading_directories(git_HEAD) < 0)
1201                 return error("unable to create directory for %s", git_HEAD);
1202
1203 #ifndef NO_SYMLINK_HEAD
1204         if (prefer_symlink_refs) {
1205                 unlink(git_HEAD);
1206                 if (!symlink(refs_heads_master, git_HEAD))
1207                         goto done;
1208                 fprintf(stderr, "no symlink - falling back to symbolic ref\n");
1209         }
1210 #endif
1211
1212         len = snprintf(ref, sizeof(ref), "ref: %s\n", refs_heads_master);
1213         if (sizeof(ref) <= len) {
1214                 error("refname too long: %s", refs_heads_master);
1215                 goto error_free_return;
1216         }
1217         lockpath = mkpath("%s.lock", git_HEAD);
1218         fd = open(lockpath, O_CREAT | O_EXCL | O_WRONLY, 0666);
1219         if (fd < 0) {
1220                 error("Unable to open %s for writing", lockpath);
1221                 goto error_free_return;
1222         }
1223         written = write_in_full(fd, ref, len);
1224         if (close(fd) != 0 || written != len) {
1225                 error("Unable to write to %s", lockpath);
1226                 goto error_unlink_return;
1227         }
1228         unlink(git_HEAD);
1229         if (rename(lockpath, git_HEAD) < 0) {
1230                 error("Unable to create %s", git_HEAD);
1231                 goto error_unlink_return;
1232         }
1233         if (adjust_shared_perm(git_HEAD)) {
1234                 error("Unable to fix permissions on %s", lockpath);
1235         error_unlink_return:
1236                 unlink(lockpath);
1237         error_free_return:
1238                 free(git_HEAD);
1239                 return -1;
1240         }
1241
1242 #ifndef NO_SYMLINK_HEAD
1243         done:
1244 #endif
1245         if (logmsg && !read_ref(refs_heads_master, new_sha1))
1246                 log_ref_write(ref_target, old_sha1, new_sha1, logmsg);
1247
1248         free(git_HEAD);
1249         return 0;
1250 }
1251
1252 static char *ref_msg(const char *line, const char *endp)
1253 {
1254         const char *ep;
1255         char *msg;
1256
1257         line += 82;
1258         for (ep = line; ep < endp && *ep != '\n'; ep++)
1259                 ;
1260         msg = xmalloc(ep - line + 1);
1261         memcpy(msg, line, ep - line);
1262         msg[ep - line] = 0;
1263         return msg;
1264 }
1265
1266 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)
1267 {
1268         const char *logfile, *logdata, *logend, *rec, *lastgt, *lastrec;
1269         char *tz_c;
1270         int logfd, tz, reccnt = 0;
1271         struct stat st;
1272         unsigned long date;
1273         unsigned char logged_sha1[20];
1274         void *log_mapped;
1275         size_t mapsz;
1276
1277         logfile = git_path("logs/%s", ref);
1278         logfd = open(logfile, O_RDONLY, 0);
1279         if (logfd < 0)
1280                 die("Unable to read log %s: %s", logfile, strerror(errno));
1281         fstat(logfd, &st);
1282         if (!st.st_size)
1283                 die("Log %s is empty.", logfile);
1284         mapsz = xsize_t(st.st_size);
1285         log_mapped = xmmap(NULL, mapsz, PROT_READ, MAP_PRIVATE, logfd, 0);
1286         logdata = log_mapped;
1287         close(logfd);
1288
1289         lastrec = NULL;
1290         rec = logend = logdata + st.st_size;
1291         while (logdata < rec) {
1292                 reccnt++;
1293                 if (logdata < rec && *(rec-1) == '\n')
1294                         rec--;
1295                 lastgt = NULL;
1296                 while (logdata < rec && *(rec-1) != '\n') {
1297                         rec--;
1298                         if (*rec == '>')
1299                                 lastgt = rec;
1300                 }
1301                 if (!lastgt)
1302                         die("Log %s is corrupt.", logfile);
1303                 date = strtoul(lastgt + 1, &tz_c, 10);
1304                 if (date <= at_time || cnt == 0) {
1305                         tz = strtoul(tz_c, NULL, 10);
1306                         if (msg)
1307                                 *msg = ref_msg(rec, logend);
1308                         if (cutoff_time)
1309                                 *cutoff_time = date;
1310                         if (cutoff_tz)
1311                                 *cutoff_tz = tz;
1312                         if (cutoff_cnt)
1313                                 *cutoff_cnt = reccnt - 1;
1314                         if (lastrec) {
1315                                 if (get_sha1_hex(lastrec, logged_sha1))
1316                                         die("Log %s is corrupt.", logfile);
1317                                 if (get_sha1_hex(rec + 41, sha1))
1318                                         die("Log %s is corrupt.", logfile);
1319                                 if (hashcmp(logged_sha1, sha1)) {
1320                                         fprintf(stderr,
1321                                                 "warning: Log %s has gap after %s.\n",
1322                                                 logfile, show_date(date, tz, DATE_RFC2822));
1323                                 }
1324                         }
1325                         else if (date == at_time) {
1326                                 if (get_sha1_hex(rec + 41, sha1))
1327                                         die("Log %s is corrupt.", logfile);
1328                         }
1329                         else {
1330                                 if (get_sha1_hex(rec + 41, logged_sha1))
1331                                         die("Log %s is corrupt.", logfile);
1332                                 if (hashcmp(logged_sha1, sha1)) {
1333                                         fprintf(stderr,
1334                                                 "warning: Log %s unexpectedly ended on %s.\n",
1335                                                 logfile, show_date(date, tz, DATE_RFC2822));
1336                                 }
1337                         }
1338                         munmap(log_mapped, mapsz);
1339                         return 0;
1340                 }
1341                 lastrec = rec;
1342                 if (cnt > 0)
1343                         cnt--;
1344         }
1345
1346         rec = logdata;
1347         while (rec < logend && *rec != '>' && *rec != '\n')
1348                 rec++;
1349         if (rec == logend || *rec == '\n')
1350                 die("Log %s is corrupt.", logfile);
1351         date = strtoul(rec + 1, &tz_c, 10);
1352         tz = strtoul(tz_c, NULL, 10);
1353         if (get_sha1_hex(logdata, sha1))
1354                 die("Log %s is corrupt.", logfile);
1355         if (msg)
1356                 *msg = ref_msg(logdata, logend);
1357         munmap(log_mapped, mapsz);
1358
1359         if (cutoff_time)
1360                 *cutoff_time = date;
1361         if (cutoff_tz)
1362                 *cutoff_tz = tz;
1363         if (cutoff_cnt)
1364                 *cutoff_cnt = reccnt;
1365         return 1;
1366 }
1367
1368 int for_each_reflog_ent(const char *ref, each_reflog_ent_fn fn, void *cb_data)
1369 {
1370         const char *logfile;
1371         FILE *logfp;
1372         char buf[1024];
1373         int ret = 0;
1374
1375         logfile = git_path("logs/%s", ref);
1376         logfp = fopen(logfile, "r");
1377         if (!logfp)
1378                 return -1;
1379         while (fgets(buf, sizeof(buf), logfp)) {
1380                 unsigned char osha1[20], nsha1[20];
1381                 char *email_end, *message;
1382                 unsigned long timestamp;
1383                 int len, tz;
1384
1385                 /* old SP new SP name <email> SP time TAB msg LF */
1386                 len = strlen(buf);
1387                 if (len < 83 || buf[len-1] != '\n' ||
1388                     get_sha1_hex(buf, osha1) || buf[40] != ' ' ||
1389                     get_sha1_hex(buf + 41, nsha1) || buf[81] != ' ' ||
1390                     !(email_end = strchr(buf + 82, '>')) ||
1391                     email_end[1] != ' ' ||
1392                     !(timestamp = strtoul(email_end + 2, &message, 10)) ||
1393                     !message || message[0] != ' ' ||
1394                     (message[1] != '+' && message[1] != '-') ||
1395                     !isdigit(message[2]) || !isdigit(message[3]) ||
1396                     !isdigit(message[4]) || !isdigit(message[5]))
1397                         continue; /* corrupt? */
1398                 email_end[1] = '\0';
1399                 tz = strtol(message + 1, NULL, 10);
1400                 if (message[6] != '\t')
1401                         message += 6;
1402                 else
1403                         message += 7;
1404                 ret = fn(osha1, nsha1, buf+82, timestamp, tz, message, cb_data);
1405                 if (ret)
1406                         break;
1407         }
1408         fclose(logfp);
1409         return ret;
1410 }
1411
1412 static int do_for_each_reflog(const char *base, each_ref_fn fn, void *cb_data)
1413 {
1414         DIR *dir = opendir(git_path("logs/%s", base));
1415         int retval = 0;
1416
1417         if (dir) {
1418                 struct dirent *de;
1419                 int baselen = strlen(base);
1420                 char *log = xmalloc(baselen + 257);
1421
1422                 memcpy(log, base, baselen);
1423                 if (baselen && base[baselen-1] != '/')
1424                         log[baselen++] = '/';
1425
1426                 while ((de = readdir(dir)) != NULL) {
1427                         struct stat st;
1428                         int namelen;
1429
1430                         if (de->d_name[0] == '.')
1431                                 continue;
1432                         namelen = strlen(de->d_name);
1433                         if (namelen > 255)
1434                                 continue;
1435                         if (has_extension(de->d_name, ".lock"))
1436                                 continue;
1437                         memcpy(log + baselen, de->d_name, namelen+1);
1438                         if (stat(git_path("logs/%s", log), &st) < 0)
1439                                 continue;
1440                         if (S_ISDIR(st.st_mode)) {
1441                                 retval = do_for_each_reflog(log, fn, cb_data);
1442                         } else {
1443                                 unsigned char sha1[20];
1444                                 if (!resolve_ref(log, sha1, 0, NULL))
1445                                         retval = error("bad ref for %s", log);
1446                                 else
1447                                         retval = fn(log, sha1, 0, cb_data);
1448                         }
1449                         if (retval)
1450                                 break;
1451                 }
1452                 free(log);
1453                 closedir(dir);
1454         }
1455         else if (*base)
1456                 return errno;
1457         return retval;
1458 }
1459
1460 int for_each_reflog(each_ref_fn fn, void *cb_data)
1461 {
1462         return do_for_each_reflog("", fn, cb_data);
1463 }