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 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         return (((unsigned) ch) <= ' ' ||
 607                 ch == '~' || ch == '^' || ch == ':' ||
 608                 /* 2.13 Pattern Matching Notation */
 609                 ch == '?' || ch == '*' || ch == '[');
 610 }
 611
 612 int check_ref_format(const char *ref)
 613 {
 614         int ch, level;
 615         const char *cp = ref;
 616
 617         level = 0;
 618         while (1) {
 619                 while ((ch = *cp++) == '/')
 620                         ; /* tolerate duplicated slashes */
 621                 if (!ch)
 622                         return -1; /* should not end with slashes */
 623
 624                 /* we are at the beginning of the path component */
 625                 if (ch == '.' || bad_ref_char(ch))
 626                         return -1;
 627
 628                 /* scan the rest of the path component */
 629                 while ((ch = *cp++) != 0) {
 630                         if (bad_ref_char(ch))
 631                                 return -1;
 632                         if (ch == '/')
 633                                 break;
 634                         if (ch == '.' && *cp == '.')
 635                                 return -1;
 636                 }
 637                 level++;
 638                 if (!ch) {
 639                         if (level < 2)
 640                                 return -2; /* at least of form "heads/blah" */
 641                         return 0;
 642                 }
 643         }
 644 }
 645
 646 static struct ref_lock *verify_lock(struct ref_lock *lock,
 647         const unsigned char *old_sha1, int mustexist)
 648 {
 649         if (!resolve_ref(lock->ref_name, lock->old_sha1, mustexist, NULL)) {
 650                 error("Can't verify ref %s", lock->ref_name);
 651                 unlock_ref(lock);
 652                 return NULL;
 653         }
 654         if (hashcmp(lock->old_sha1, old_sha1)) {
 655                 error("Ref %s is at %s but expected %s", lock->ref_name,
 656                         sha1_to_hex(lock->old_sha1), sha1_to_hex(old_sha1));
 657                 unlock_ref(lock);
 658                 return NULL;
 659         }
 660         return lock;
 661 }
 662
 663 static int remove_empty_dir_recursive(char *path, int len)
 664 {
 665         DIR *dir = opendir(path);
 666         struct dirent *e;
 667         int ret = 0;
 668
 669         if (!dir)
 670                 return -1;
 671         if (path[len-1] != '/')
 672                 path[len++] = '/';
 673         while ((e = readdir(dir)) != NULL) {
 674                 struct stat st;
 675                 int namlen;
 676                 if ((e->d_name[0] == '.') &&
 677                     ((e->d_name[1] == 0) ||
 678                      ((e->d_name[1] == '.') && e->d_name[2] == 0)))
 679                         continue; /* "." and ".." */
 680
 681                 namlen = strlen(e->d_name);
 682                 if ((len + namlen < PATH_MAX) &&
 683                     strcpy(path + len, e->d_name) &&
 684                     !lstat(path, &st) &&
 685                     S_ISDIR(st.st_mode) &&
 686                     !remove_empty_dir_recursive(path, len + namlen))
 687                         continue; /* happy */
 688
 689                 /* path too long, stat fails, or non-directory still exists */
 690                 ret = -1;
 691                 break;
 692         }
 693         closedir(dir);
 694         if (!ret) {
 695                 path[len] = 0;
 696                 ret = rmdir(path);
 697         }
 698         return ret;
 699 }
 700
 701 static int remove_empty_directories(char *file)
 702 {
 703         /* we want to create a file but there is a directory there;
 704          * if that is an empty directory (or a directory that contains
 705          * only empty directories), remove them.
 706          */
 707         char path[PATH_MAX];
 708         int len = strlen(file);
 709
 710         if (len >= PATH_MAX) /* path too long ;-) */
 711                 return -1;
 712         strcpy(path, file);
 713         return remove_empty_dir_recursive(path, len);
 714 }
 715
 716 static int is_refname_available(const char *ref, const char *oldref,
 717                                 struct ref_list *list, int quiet)
 718 {
 719         int namlen = strlen(ref); /* e.g. 'foo/bar' */
 720         while (list) {
 721                 /* list->name could be 'foo' or 'foo/bar/baz' */
 722                 if (!oldref || strcmp(oldref, list->name)) {
 723                         int len = strlen(list->name);
 724                         int cmplen = (namlen < len) ? namlen : len;
 725                         const char *lead = (namlen < len) ? list->name : ref;
 726                         if (!strncmp(ref, list->name, cmplen) &&
 727                             lead[cmplen] == '/') {
 728                                 if (!quiet)
 729                                         error("'%s' exists; cannot create '%s'",
 730                                               list->name, ref);
 731                                 return 0;
 732                         }
 733                 }
 734                 list = list->next;
 735         }
 736         return 1;
 737 }
 738
 739 static struct ref_lock *lock_ref_sha1_basic(const char *ref, const unsigned char *old_sha1, int flags, int *type_p)
 740 {
 741         char *ref_file;
 742         const char *orig_ref = ref;
 743         struct ref_lock *lock;
 744         struct stat st;
 745         int last_errno = 0;
 746         int type;
 747         int mustexist = (old_sha1 && !is_null_sha1(old_sha1));
 748
 749         lock = xcalloc(1, sizeof(struct ref_lock));
 750         lock->lock_fd = -1;
 751
 752         ref = resolve_ref(ref, lock->old_sha1, mustexist, &type);
 753         if (!ref && errno == EISDIR) {
 754                 /* we are trying to lock foo but we used to
 755                  * have foo/bar which now does not exist;
 756                  * it is normal for the empty directory 'foo'
 757                  * to remain.
 758                  */
 759                 ref_file = git_path("%s", orig_ref);
 760                 if (remove_empty_directories(ref_file)) {
 761                         last_errno = errno;
 762                         error("there are still refs under '%s'", orig_ref);
 763                         goto error_return;
 764                 }
 765                 ref = resolve_ref(orig_ref, lock->old_sha1, mustexist, &type);
 766         }
 767         if (type_p)
 768             *type_p = type;
 769         if (!ref) {
 770                 last_errno = errno;
 771                 error("unable to resolve reference %s: %s",
 772                         orig_ref, strerror(errno));
 773                 goto error_return;
 774         }
 775         /* When the ref did not exist and we are creating it,
 776          * make sure there is no existing ref that is packed
 777          * whose name begins with our refname, nor a ref whose
 778          * name is a proper prefix of our refname.
 779          */
 780         if (is_null_sha1(lock->old_sha1) &&
 781             !is_refname_available(ref, NULL, get_packed_refs(), 0))
 782                 goto error_return;
 783
 784         lock->lk = xcalloc(1, sizeof(struct lock_file));
 785
 786         if (flags & REF_NODEREF)
 787                 ref = orig_ref;
 788         lock->ref_name = xstrdup(ref);
 789         lock->orig_ref_name = xstrdup(orig_ref);
 790         ref_file = git_path("%s", ref);
 791         if (lstat(ref_file, &st) && errno == ENOENT)
 792                 lock->force_write = 1;
 793         if ((flags & REF_NODEREF) && (type & REF_ISSYMREF))
 794                 lock->force_write = 1;
 795
 796         if (safe_create_leading_directories(ref_file)) {
 797                 last_errno = errno;
 798                 error("unable to create directory for %s", ref_file);
 799                 goto error_return;
 800         }
 801         lock->lock_fd = hold_lock_file_for_update(lock->lk, ref_file, 1);
 802
 803         return old_sha1 ? verify_lock(lock, old_sha1, mustexist) : lock;
 804
 805  error_return:
 806         unlock_ref(lock);
 807         errno = last_errno;
 808         return NULL;
 809 }
 810
 811 struct ref_lock *lock_ref_sha1(const char *ref, const unsigned char *old_sha1)
 812 {
 813         char refpath[PATH_MAX];
 814         if (check_ref_format(ref))
 815                 return NULL;
 816         strcpy(refpath, mkpath("refs/%s", ref));
 817         return lock_ref_sha1_basic(refpath, old_sha1, 0, NULL);
 818 }
 819
 820 struct ref_lock *lock_any_ref_for_update(const char *ref, const unsigned char *old_sha1, int flags)
 821 {
 822         if (check_ref_format(ref) == -1)
 823                 return NULL;
 824         return lock_ref_sha1_basic(ref, old_sha1, flags, NULL);
 825 }
 826
 827 static struct lock_file packlock;
 828
 829 static int repack_without_ref(const char *refname)
 830 {
 831         struct ref_list *list, *packed_ref_list;
 832         int fd;
 833         int found = 0;
 834
 835         packed_ref_list = get_packed_refs();
 836         for (list = packed_ref_list; list; list = list->next) {
 837                 if (!strcmp(refname, list->name)) {
 838                         found = 1;
 839                         break;
 840                 }
 841         }
 842         if (!found)
 843                 return 0;
 844         fd = hold_lock_file_for_update(&packlock, git_path("packed-refs"), 0);
 845         if (fd < 0)
 846                 return error("cannot delete '%s' from packed refs", refname);
 847
 848         for (list = packed_ref_list; list; list = list->next) {
 849                 char line[PATH_MAX + 100];
 850                 int len;
 851
 852                 if (!strcmp(refname, list->name))
 853                         continue;
 854                 len = snprintf(line, sizeof(line), "%s %s\n",
 855                                sha1_to_hex(list->sha1), list->name);
 856                 /* this should not happen but just being defensive */
 857                 if (len > sizeof(line))
 858                         die("too long a refname '%s'", list->name);
 859                 write_or_die(fd, line, len);
 860         }
 861         return commit_lock_file(&packlock);
 862 }
 863
 864 int delete_ref(const char *refname, const unsigned char *sha1)
 865 {
 866         struct ref_lock *lock;
 867         int err, i, ret = 0, flag = 0;
 868
 869         lock = lock_ref_sha1_basic(refname, sha1, 0, &flag);
 870         if (!lock)
 871                 return 1;
 872         if (!(flag & REF_ISPACKED)) {
 873                 /* loose */
 874                 i = strlen(lock->lk->filename) - 5; /* .lock */
 875                 lock->lk->filename[i] = 0;
 876                 err = unlink(lock->lk->filename);
 877                 if (err) {
 878                         ret = 1;
 879                         error("unlink(%s) failed: %s",
 880                               lock->lk->filename, strerror(errno));
 881                 }
 882                 lock->lk->filename[i] = '.';
 883         }
 884         /* removing the loose one could have resurrected an earlier
 885          * packed one.  Also, if it was not loose we need to repack
 886          * without it.
 887          */
 888         ret |= repack_without_ref(refname);
 889
 890         err = unlink(git_path("logs/%s", lock->ref_name));
 891         if (err && errno != ENOENT)
 892                 fprintf(stderr, "warning: unlink(%s) failed: %s",
 893                         git_path("logs/%s", lock->ref_name), strerror(errno));
 894         invalidate_cached_refs();
 895         unlock_ref(lock);
 896         return ret;
 897 }
 898
 899 int rename_ref(const char *oldref, const char *newref, const char *logmsg)
 900 {
 901         static const char renamed_ref[] = "RENAMED-REF";
 902         unsigned char sha1[20], orig_sha1[20];
 903         int flag = 0, logmoved = 0;
 904         struct ref_lock *lock;
 905         struct stat loginfo;
 906         int log = !lstat(git_path("logs/%s", oldref), &loginfo);
 907
 908         if (S_ISLNK(loginfo.st_mode))
 909                 return error("reflog for %s is a symlink", oldref);
 910
 911         if (!resolve_ref(oldref, orig_sha1, 1, &flag))
 912                 return error("refname %s not found", oldref);
 913
 914         if (!is_refname_available(newref, oldref, get_packed_refs(), 0))
 915                 return 1;
 916
 917         if (!is_refname_available(newref, oldref, get_loose_refs(), 0))
 918                 return 1;
 919
 920         lock = lock_ref_sha1_basic(renamed_ref, NULL, 0, NULL);
 921         if (!lock)
 922                 return error("unable to lock %s", renamed_ref);
 923         lock->force_write = 1;
 924         if (write_ref_sha1(lock, orig_sha1, logmsg))
 925                 return error("unable to save current sha1 in %s", renamed_ref);
 926
 927         if (log && rename(git_path("logs/%s", oldref), git_path("tmp-renamed-log")))
 928                 return error("unable to move logfile logs/%s to tmp-renamed-log: %s",
 929                         oldref, strerror(errno));
 930
 931         if (delete_ref(oldref, orig_sha1)) {
 932                 error("unable to delete old %s", oldref);
 933                 goto rollback;
 934         }
 935
 936         if (resolve_ref(newref, sha1, 1, &flag) && delete_ref(newref, sha1)) {
 937                 if (errno==EISDIR) {
 938                         if (remove_empty_directories(git_path("%s", newref))) {
 939                                 error("Directory not empty: %s", newref);
 940                                 goto rollback;
 941                         }
 942                 } else {
 943                         error("unable to delete existing %s", newref);
 944                         goto rollback;
 945                 }
 946         }
 947
 948         if (log && safe_create_leading_directories(git_path("logs/%s", newref))) {
 949                 error("unable to create directory for %s", newref);
 950                 goto rollback;
 951         }
 952
 953  retry:
 954         if (log && rename(git_path("tmp-renamed-log"), git_path("logs/%s", newref))) {
 955                 if (errno==EISDIR || errno==ENOTDIR) {
 956                         /*
 957                          * rename(a, b) when b is an existing
 958                          * directory ought to result in ISDIR, but
 959                          * Solaris 5.8 gives ENOTDIR.  Sheesh.
 960                          */
 961                         if (remove_empty_directories(git_path("logs/%s", newref))) {
 962                                 error("Directory not empty: logs/%s", newref);
 963                                 goto rollback;
 964                         }
 965                         goto retry;
 966                 } else {
 967                         error("unable to move logfile tmp-renamed-log to logs/%s: %s",
 968                                 newref, strerror(errno));
 969                         goto rollback;
 970                 }
 971         }
 972         logmoved = log;
 973
 974         lock = lock_ref_sha1_basic(newref, NULL, 0, NULL);
 975         if (!lock) {
 976                 error("unable to lock %s for update", newref);
 977                 goto rollback;
 978         }
 979
 980         lock->force_write = 1;
 981         hashcpy(lock->old_sha1, orig_sha1);
 982         if (write_ref_sha1(lock, orig_sha1, logmsg)) {
 983                 error("unable to write current sha1 into %s", newref);
 984                 goto rollback;
 985         }
 986
 987         return 0;
 988
 989  rollback:
 990         lock = lock_ref_sha1_basic(oldref, NULL, 0, NULL);
 991         if (!lock) {
 992                 error("unable to lock %s for rollback", oldref);
 993                 goto rollbacklog;
 994         }
 995
 996         lock->force_write = 1;
 997         flag = log_all_ref_updates;
 998         log_all_ref_updates = 0;
 999         if (write_ref_sha1(lock, orig_sha1, NULL))
1000                 error("unable to write current sha1 into %s", oldref);
1001         log_all_ref_updates = flag;
1002
1003  rollbacklog:
1004         if (logmoved && rename(git_path("logs/%s", newref), git_path("logs/%s", oldref)))
1005                 error("unable to restore logfile %s from %s: %s",
1006                         oldref, newref, strerror(errno));
1007         if (!logmoved && log &&
1008             rename(git_path("tmp-renamed-log"), git_path("logs/%s", oldref)))
1009                 error("unable to restore logfile %s from tmp-renamed-log: %s",
1010                         oldref, strerror(errno));
1011
1012         return 1;
1013 }
1014
1015 void unlock_ref(struct ref_lock *lock)
1016 {
1017         if (lock->lock_fd >= 0) {
1018                 close(lock->lock_fd);
1019                 /* Do not free lock->lk -- atexit() still looks at them */
1020                 if (lock->lk)
1021                         rollback_lock_file(lock->lk);
1022         }
1023         free(lock->ref_name);
1024         free(lock->orig_ref_name);
1025         free(lock);
1026 }
1027
1028 static int log_ref_write(const char *ref_name, const unsigned char *old_sha1,
1029                          const unsigned char *new_sha1, const char *msg)
1030 {
1031         int logfd, written, oflags = O_APPEND | O_WRONLY;
1032         unsigned maxlen, len;
1033         int msglen;
1034         char *log_file, *logrec;
1035         const char *committer;
1036
1037         if (log_all_ref_updates < 0)
1038                 log_all_ref_updates = !is_bare_repository();
1039
1040         log_file = git_path("logs/%s", ref_name);
1041
1042         if (log_all_ref_updates &&
1043             (!prefixcmp(ref_name, "refs/heads/") ||
1044              !prefixcmp(ref_name, "refs/remotes/") ||
1045              !strcmp(ref_name, "HEAD"))) {
1046                 if (safe_create_leading_directories(log_file) < 0)
1047                         return error("unable to create directory for %s",
1048                                      log_file);
1049                 oflags |= O_CREAT;
1050         }
1051
1052         logfd = open(log_file, oflags, 0666);
1053         if (logfd < 0) {
1054                 if (!(oflags & O_CREAT) && errno == ENOENT)
1055                         return 0;
1056
1057                 if ((oflags & O_CREAT) && errno == EISDIR) {
1058                         if (remove_empty_directories(log_file)) {
1059                                 return error("There are still logs under '%s'",
1060                                              log_file);
1061                         }
1062                         logfd = open(log_file, oflags, 0666);
1063                 }
1064
1065                 if (logfd < 0)
1066                         return error("Unable to append to %s: %s",
1067                                      log_file, strerror(errno));
1068         }
1069
1070         adjust_shared_perm(log_file);
1071
1072         msglen = 0;
1073         if (msg) {
1074                 /* clean up the message and make sure it is a single line */
1075                 for ( ; *msg; msg++)
1076                         if (!isspace(*msg))
1077                                 break;
1078                 if (*msg) {
1079                         const char *ep = strchr(msg, '\n');
1080                         if (ep)
1081                                 msglen = ep - msg;
1082                         else
1083                                 msglen = strlen(msg);
1084                 }
1085         }
1086
1087         committer = git_committer_info(-1);
1088         maxlen = strlen(committer) + msglen + 100;
1089         logrec = xmalloc(maxlen);
1090         len = sprintf(logrec, "%s %s %s\n",
1091                       sha1_to_hex(old_sha1),
1092                       sha1_to_hex(new_sha1),
1093                       committer);
1094         if (msglen)
1095                 len += sprintf(logrec + len - 1, "\t%.*s\n", msglen, msg) - 1;
1096         written = len <= maxlen ? write_in_full(logfd, logrec, len) : -1;
1097         free(logrec);
1098         close(logfd);
1099         if (written != len)
1100                 return error("Unable to append to %s", log_file);
1101         return 0;
1102 }
1103
1104 int write_ref_sha1(struct ref_lock *lock,
1105         const unsigned char *sha1, const char *logmsg)
1106 {
1107         static char term = '\n';
1108
1109         if (!lock)
1110                 return -1;
1111         if (!lock->force_write && !hashcmp(lock->old_sha1, sha1)) {
1112                 unlock_ref(lock);
1113                 return 0;
1114         }
1115         if (write_in_full(lock->lock_fd, sha1_to_hex(sha1), 40) != 40 ||
1116             write_in_full(lock->lock_fd, &term, 1) != 1
1117                 || close(lock->lock_fd) < 0) {
1118                 error("Couldn't write %s", lock->lk->filename);
1119                 unlock_ref(lock);
1120                 return -1;
1121         }
1122         invalidate_cached_refs();
1123         if (log_ref_write(lock->ref_name, lock->old_sha1, sha1, logmsg) < 0 ||
1124             (strcmp(lock->ref_name, lock->orig_ref_name) &&
1125              log_ref_write(lock->orig_ref_name, lock->old_sha1, sha1, logmsg) < 0)) {
1126                 unlock_ref(lock);
1127                 return -1;
1128         }
1129         if (strcmp(lock->orig_ref_name, "HEAD") != 0) {
1130                 /*
1131                  * Special hack: If a branch is updated directly and HEAD
1132                  * points to it (may happen on the remote side of a push
1133                  * for example) then logically the HEAD reflog should be
1134                  * updated too.
1135                  * A generic solution implies reverse symref information,
1136                  * but finding all symrefs pointing to the given branch
1137                  * would be rather costly for this rare event (the direct
1138                  * update of a branch) to be worth it.  So let's cheat and
1139                  * check with HEAD only which should cover 99% of all usage
1140                  * scenarios (even 100% of the default ones).
1141                  */
1142                 unsigned char head_sha1[20];
1143                 int head_flag;
1144                 const char *head_ref;
1145                 head_ref = resolve_ref("HEAD", head_sha1, 1, &head_flag);
1146                 if (head_ref && (head_flag & REF_ISSYMREF) &&
1147                     !strcmp(head_ref, lock->ref_name))
1148                         log_ref_write("HEAD", lock->old_sha1, sha1, logmsg);
1149         }
1150         if (commit_lock_file(lock->lk)) {
1151                 error("Couldn't set %s", lock->ref_name);
1152                 unlock_ref(lock);
1153                 return -1;
1154         }
1155         lock->lock_fd = -1;
1156         unlock_ref(lock);
1157         return 0;
1158 }
1159
1160 int create_symref(const char *ref_target, const char *refs_heads_master,
1161                   const char *logmsg)
1162 {
1163         const char *lockpath;
1164         char ref[1000];
1165         int fd, len, written;
1166         char *git_HEAD = xstrdup(git_path("%s", ref_target));
1167         unsigned char old_sha1[20], new_sha1[20];
1168
1169         if (logmsg && read_ref(ref_target, old_sha1))
1170                 hashclr(old_sha1);
1171
1172         if (safe_create_leading_directories(git_HEAD) < 0)
1173                 return error("unable to create directory for %s", git_HEAD);
1174
1175 #ifndef NO_SYMLINK_HEAD
1176         if (prefer_symlink_refs) {
1177                 unlink(git_HEAD);
1178                 if (!symlink(refs_heads_master, git_HEAD))
1179                         goto done;
1180                 fprintf(stderr, "no symlink - falling back to symbolic ref\n");
1181         }
1182 #endif
1183
1184         len = snprintf(ref, sizeof(ref), "ref: %s\n", refs_heads_master);
1185         if (sizeof(ref) <= len) {
1186                 error("refname too long: %s", refs_heads_master);
1187                 goto error_free_return;
1188         }
1189         lockpath = mkpath("%s.lock", git_HEAD);
1190         fd = open(lockpath, O_CREAT | O_EXCL | O_WRONLY, 0666);
1191         if (fd < 0) {
1192                 error("Unable to open %s for writing", lockpath);
1193                 goto error_free_return;
1194         }
1195         written = write_in_full(fd, ref, len);
1196         close(fd);
1197         if (written != len) {
1198                 error("Unable to write to %s", lockpath);
1199                 goto error_unlink_return;
1200         }
1201         if (rename(lockpath, git_HEAD) < 0) {
1202                 error("Unable to create %s", git_HEAD);
1203                 goto error_unlink_return;
1204         }
1205         if (adjust_shared_perm(git_HEAD)) {
1206                 error("Unable to fix permissions on %s", lockpath);
1207         error_unlink_return:
1208                 unlink(lockpath);
1209         error_free_return:
1210                 free(git_HEAD);
1211                 return -1;
1212         }
1213
1214 #ifndef NO_SYMLINK_HEAD
1215         done:
1216 #endif
1217         if (logmsg && !read_ref(refs_heads_master, new_sha1))
1218                 log_ref_write(ref_target, old_sha1, new_sha1, logmsg);
1219
1220         free(git_HEAD);
1221         return 0;
1222 }
1223
1224 static char *ref_msg(const char *line, const char *endp)
1225 {
1226         const char *ep;
1227         char *msg;
1228
1229         line += 82;
1230         for (ep = line; ep < endp && *ep != '\n'; ep++)
1231                 ;
1232         msg = xmalloc(ep - line + 1);
1233         memcpy(msg, line, ep - line);
1234         msg[ep - line] = 0;
1235         return msg;
1236 }
1237
1238 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)
1239 {
1240         const char *logfile, *logdata, *logend, *rec, *lastgt, *lastrec;
1241         char *tz_c;
1242         int logfd, tz, reccnt = 0;
1243         struct stat st;
1244         unsigned long date;
1245         unsigned char logged_sha1[20];
1246         void *log_mapped;
1247         size_t mapsz;
1248
1249         logfile = git_path("logs/%s", ref);
1250         logfd = open(logfile, O_RDONLY, 0);
1251         if (logfd < 0)
1252                 die("Unable to read log %s: %s", logfile, strerror(errno));
1253         fstat(logfd, &st);
1254         if (!st.st_size)
1255                 die("Log %s is empty.", logfile);
1256         mapsz = xsize_t(st.st_size);
1257         log_mapped = xmmap(NULL, mapsz, PROT_READ, MAP_PRIVATE, logfd, 0);
1258         logdata = log_mapped;
1259         close(logfd);
1260
1261         lastrec = NULL;
1262         rec = logend = logdata + st.st_size;
1263         while (logdata < rec) {
1264                 reccnt++;
1265                 if (logdata < rec && *(rec-1) == '\n')
1266                         rec--;
1267                 lastgt = NULL;
1268                 while (logdata < rec && *(rec-1) != '\n') {
1269                         rec--;
1270                         if (*rec == '>')
1271                                 lastgt = rec;
1272                 }
1273                 if (!lastgt)
1274                         die("Log %s is corrupt.", logfile);
1275                 date = strtoul(lastgt + 1, &tz_c, 10);
1276                 if (date <= at_time || cnt == 0) {
1277                         tz = strtoul(tz_c, NULL, 10);
1278                         if (msg)
1279                                 *msg = ref_msg(rec, logend);
1280                         if (cutoff_time)
1281                                 *cutoff_time = date;
1282                         if (cutoff_tz)
1283                                 *cutoff_tz = tz;
1284                         if (cutoff_cnt)
1285                                 *cutoff_cnt = reccnt - 1;
1286                         if (lastrec) {
1287                                 if (get_sha1_hex(lastrec, logged_sha1))
1288                                         die("Log %s is corrupt.", logfile);
1289                                 if (get_sha1_hex(rec + 41, sha1))
1290                                         die("Log %s is corrupt.", logfile);
1291                                 if (hashcmp(logged_sha1, sha1)) {
1292                                         fprintf(stderr,
1293                                                 "warning: Log %s has gap after %s.\n",
1294                                                 logfile, show_rfc2822_date(date, tz));
1295                                 }
1296                         }
1297                         else if (date == at_time) {
1298                                 if (get_sha1_hex(rec + 41, sha1))
1299                                         die("Log %s is corrupt.", logfile);
1300                         }
1301                         else {
1302                                 if (get_sha1_hex(rec + 41, logged_sha1))
1303                                         die("Log %s is corrupt.", logfile);
1304                                 if (hashcmp(logged_sha1, sha1)) {
1305                                         fprintf(stderr,
1306                                                 "warning: Log %s unexpectedly ended on %s.\n",
1307                                                 logfile, show_rfc2822_date(date, tz));
1308                                 }
1309                         }
1310                         munmap(log_mapped, mapsz);
1311                         return 0;
1312                 }
1313                 lastrec = rec;
1314                 if (cnt > 0)
1315                         cnt--;
1316         }
1317
1318         rec = logdata;
1319         while (rec < logend && *rec != '>' && *rec != '\n')
1320                 rec++;
1321         if (rec == logend || *rec == '\n')
1322                 die("Log %s is corrupt.", logfile);
1323         date = strtoul(rec + 1, &tz_c, 10);
1324         tz = strtoul(tz_c, NULL, 10);
1325         if (get_sha1_hex(logdata, sha1))
1326                 die("Log %s is corrupt.", logfile);
1327         if (msg)
1328                 *msg = ref_msg(logdata, logend);
1329         munmap(log_mapped, mapsz);
1330
1331         if (cutoff_time)
1332                 *cutoff_time = date;
1333         if (cutoff_tz)
1334                 *cutoff_tz = tz;
1335         if (cutoff_cnt)
1336                 *cutoff_cnt = reccnt;
1337         return 1;
1338 }
1339
1340 int for_each_reflog_ent(const char *ref, each_reflog_ent_fn fn, void *cb_data)
1341 {
1342         const char *logfile;
1343         FILE *logfp;
1344         char buf[1024];
1345         int ret = 0;
1346
1347         logfile = git_path("logs/%s", ref);
1348         logfp = fopen(logfile, "r");
1349         if (!logfp)
1350                 return -1;
1351         while (fgets(buf, sizeof(buf), logfp)) {
1352                 unsigned char osha1[20], nsha1[20];
1353                 char *email_end, *message;
1354                 unsigned long timestamp;
1355                 int len, tz;
1356
1357                 /* old SP new SP name <email> SP time TAB msg LF */
1358                 len = strlen(buf);
1359                 if (len < 83 || buf[len-1] != '\n' ||
1360                     get_sha1_hex(buf, osha1) || buf[40] != ' ' ||
1361                     get_sha1_hex(buf + 41, nsha1) || buf[81] != ' ' ||
1362                     !(email_end = strchr(buf + 82, '>')) ||
1363                     email_end[1] != ' ' ||
1364                     !(timestamp = strtoul(email_end + 2, &message, 10)) ||
1365                     !message || message[0] != ' ' ||
1366                     (message[1] != '+' && message[1] != '-') ||
1367                     !isdigit(message[2]) || !isdigit(message[3]) ||
1368                     !isdigit(message[4]) || !isdigit(message[5]))
1369                         continue; /* corrupt? */
1370                 email_end[1] = '\0';
1371                 tz = strtol(message + 1, NULL, 10);
1372                 if (message[6] != '\t')
1373                         message += 6;
1374                 else
1375                         message += 7;
1376                 ret = fn(osha1, nsha1, buf+82, timestamp, tz, message, cb_data);
1377                 if (ret)
1378                         break;
1379         }
1380         fclose(logfp);
1381         return ret;
1382 }
1383
1384 static int do_for_each_reflog(const char *base, each_ref_fn fn, void *cb_data)
1385 {
1386         DIR *dir = opendir(git_path("logs/%s", base));
1387         int retval = 0;
1388
1389         if (dir) {
1390                 struct dirent *de;
1391                 int baselen = strlen(base);
1392                 char *log = xmalloc(baselen + 257);
1393
1394                 memcpy(log, base, baselen);
1395                 if (baselen && base[baselen-1] != '/')
1396                         log[baselen++] = '/';
1397
1398                 while ((de = readdir(dir)) != NULL) {
1399                         struct stat st;
1400                         int namelen;
1401
1402                         if (de->d_name[0] == '.')
1403                                 continue;
1404                         namelen = strlen(de->d_name);
1405                         if (namelen > 255)
1406                                 continue;
1407                         if (has_extension(de->d_name, ".lock"))
1408                                 continue;
1409                         memcpy(log + baselen, de->d_name, namelen+1);
1410                         if (stat(git_path("logs/%s", log), &st) < 0)
1411                                 continue;
1412                         if (S_ISDIR(st.st_mode)) {
1413                                 retval = do_for_each_reflog(log, fn, cb_data);
1414                         } else {
1415                                 unsigned char sha1[20];
1416                                 if (!resolve_ref(log, sha1, 0, NULL))
1417                                         retval = error("bad ref for %s", log);
1418                                 else
1419                                         retval = fn(log, sha1, 0, cb_data);
1420                         }
1421                         if (retval)
1422                                 break;
1423                 }
1424                 free(log);
1425                 closedir(dir);
1426         }
1427         else if (*base)
1428                 return errno;
1429         return retval;
1430 }
1431
1432 int for_each_reflog(each_ref_fn fn, void *cb_data)
1433 {
1434         return do_for_each_reflog("", fn, cb_data);
1435 }