git.oblomov.eu Git - git/blob - refs.c

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