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 /* NEEDSWORK: This is only used by ssh-upload and it should go; the
 584  * caller should do resolve_ref or read_ref like everybody else.  Or
 585  * maybe everybody else should use get_ref_sha1() instead of doing
 586  * read_ref().
 587  */
 588 int get_ref_sha1(const char *ref, unsigned char *sha1)
 589 {
 590         if (check_ref_format(ref))
 591                 return -1;
 592         return read_ref(mkpath("refs/%s", ref), sha1);
 593 }
 594
 595 /*
 596  * Make sure "ref" is something reasonable to have under ".git/refs/";
 597  * We do not like it if:
 598  *
 599  * - any path component of it begins with ".", or
 600  * - it has double dots "..", or
 601  * - it has ASCII control character, "~", "^", ":" or SP, anywhere, or
 602  * - it ends with a "/".
 603  */
 604
 605 static inline int bad_ref_char(int ch)
 606 {
 607         if (((unsigned) ch) <= ' ' ||
 608             ch == '~' || ch == '^' || ch == ':')
 609                 return 1;
 610         /* 2.13 Pattern Matching Notation */
 611         if (ch == '?' || ch == '[') /* Unsupported */
 612                 return 1;
 613         if (ch == '*') /* Supported at the end */
 614                 return 2;
 615         return 0;
 616 }
 617
 618 int check_ref_format(const char *ref)
 619 {
 620         int ch, level, bad_type;
 621         const char *cp = ref;
 622
 623         level = 0;
 624         while (1) {
 625                 while ((ch = *cp++) == '/')
 626                         ; /* tolerate duplicated slashes */
 627                 if (!ch)
 628                         return -1; /* should not end with slashes */
 629
 630                 /* we are at the beginning of the path component */
 631                 if (ch == '.')
 632                         return -1;
 633                 bad_type = bad_ref_char(ch);
 634                 if (bad_type) {
 635                         return (bad_type == 2 && !*cp) ? -3 : -1;
 636                 }
 637
 638                 /* scan the rest of the path component */
 639                 while ((ch = *cp++) != 0) {
 640                         bad_type = bad_ref_char(ch);
 641                         if (bad_type) {
 642                                 return (bad_type == 2 && !*cp) ? -3 : -1;
 643                         }
 644                         if (ch == '/')
 645                                 break;
 646                         if (ch == '.' && *cp == '.')
 647                                 return -1;
 648                 }
 649                 level++;
 650                 if (!ch) {
 651                         if (level < 2)
 652                                 return -2; /* at least of form "heads/blah" */
 653                         return 0;
 654                 }
 655         }
 656 }
 657
 658 static struct ref_lock *verify_lock(struct ref_lock *lock,
 659         const unsigned char *old_sha1, int mustexist)
 660 {
 661         if (!resolve_ref(lock->ref_name, lock->old_sha1, mustexist, NULL)) {
 662                 error("Can't verify ref %s", lock->ref_name);
 663                 unlock_ref(lock);
 664                 return NULL;
 665         }
 666         if (hashcmp(lock->old_sha1, old_sha1)) {
 667                 error("Ref %s is at %s but expected %s", lock->ref_name,
 668                         sha1_to_hex(lock->old_sha1), sha1_to_hex(old_sha1));
 669                 unlock_ref(lock);
 670                 return NULL;
 671         }
 672         return lock;
 673 }
 674
 675 static int remove_empty_directories(const char *file)
 676 {
 677         /* we want to create a file but there is a directory there;
 678          * if that is an empty directory (or a directory that contains
 679          * only empty directories), remove them.
 680          */
 681         struct strbuf path;
 682         int result;
 683
 684         strbuf_init(&path, 20);
 685         strbuf_addstr(&path, file);
 686
 687         result = remove_dir_recursively(&path, 1);
 688
 689         strbuf_release(&path);
 690
 691         return result;
 692 }
 693
 694 static int is_refname_available(const char *ref, const char *oldref,
 695                                 struct ref_list *list, int quiet)
 696 {
 697         int namlen = strlen(ref); /* e.g. 'foo/bar' */
 698         while (list) {
 699                 /* list->name could be 'foo' or 'foo/bar/baz' */
 700                 if (!oldref || strcmp(oldref, list->name)) {
 701                         int len = strlen(list->name);
 702                         int cmplen = (namlen < len) ? namlen : len;
 703                         const char *lead = (namlen < len) ? list->name : ref;
 704                         if (!strncmp(ref, list->name, cmplen) &&
 705                             lead[cmplen] == '/') {
 706                                 if (!quiet)
 707                                         error("'%s' exists; cannot create '%s'",
 708                                               list->name, ref);
 709                                 return 0;
 710                         }
 711                 }
 712                 list = list->next;
 713         }
 714         return 1;
 715 }
 716
 717 static struct ref_lock *lock_ref_sha1_basic(const char *ref, const unsigned char *old_sha1, int flags, int *type_p)
 718 {
 719         char *ref_file;
 720         const char *orig_ref = ref;
 721         struct ref_lock *lock;
 722         struct stat st;
 723         int last_errno = 0;
 724         int type;
 725         int mustexist = (old_sha1 && !is_null_sha1(old_sha1));
 726
 727         lock = xcalloc(1, sizeof(struct ref_lock));
 728         lock->lock_fd = -1;
 729
 730         ref = resolve_ref(ref, lock->old_sha1, mustexist, &type);
 731         if (!ref && errno == EISDIR) {
 732                 /* we are trying to lock foo but we used to
 733                  * have foo/bar which now does not exist;
 734                  * it is normal for the empty directory 'foo'
 735                  * to remain.
 736                  */
 737                 ref_file = git_path("%s", orig_ref);
 738                 if (remove_empty_directories(ref_file)) {
 739                         last_errno = errno;
 740                         error("there are still refs under '%s'", orig_ref);
 741                         goto error_return;
 742                 }
 743                 ref = resolve_ref(orig_ref, lock->old_sha1, mustexist, &type);
 744         }
 745         if (type_p)
 746             *type_p = type;
 747         if (!ref) {
 748                 last_errno = errno;
 749                 error("unable to resolve reference %s: %s",
 750                         orig_ref, strerror(errno));
 751                 goto error_return;
 752         }
 753         /* When the ref did not exist and we are creating it,
 754          * make sure there is no existing ref that is packed
 755          * whose name begins with our refname, nor a ref whose
 756          * name is a proper prefix of our refname.
 757          */
 758         if (is_null_sha1(lock->old_sha1) &&
 759             !is_refname_available(ref, NULL, get_packed_refs(), 0))
 760                 goto error_return;
 761
 762         lock->lk = xcalloc(1, sizeof(struct lock_file));
 763
 764         if (flags & REF_NODEREF)
 765                 ref = orig_ref;
 766         lock->ref_name = xstrdup(ref);
 767         lock->orig_ref_name = xstrdup(orig_ref);
 768         ref_file = git_path("%s", ref);
 769         if (lstat(ref_file, &st) && errno == ENOENT)
 770                 lock->force_write = 1;
 771         if ((flags & REF_NODEREF) && (type & REF_ISSYMREF))
 772                 lock->force_write = 1;
 773
 774         if (safe_create_leading_directories(ref_file)) {
 775                 last_errno = errno;
 776                 error("unable to create directory for %s", ref_file);
 777                 goto error_return;
 778         }
 779         lock->lock_fd = hold_lock_file_for_update(lock->lk, ref_file, 1);
 780
 781         return old_sha1 ? verify_lock(lock, old_sha1, mustexist) : lock;
 782
 783  error_return:
 784         unlock_ref(lock);
 785         errno = last_errno;
 786         return NULL;
 787 }
 788
 789 struct ref_lock *lock_ref_sha1(const char *ref, const unsigned char *old_sha1)
 790 {
 791         char refpath[PATH_MAX];
 792         if (check_ref_format(ref))
 793                 return NULL;
 794         strcpy(refpath, mkpath("refs/%s", ref));
 795         return lock_ref_sha1_basic(refpath, old_sha1, 0, NULL);
 796 }
 797
 798 struct ref_lock *lock_any_ref_for_update(const char *ref, const unsigned char *old_sha1, int flags)
 799 {
 800         if (check_ref_format(ref) == -1)
 801                 return NULL;
 802         return lock_ref_sha1_basic(ref, old_sha1, flags, NULL);
 803 }
 804
 805 static struct lock_file packlock;
 806
 807 static int repack_without_ref(const char *refname)
 808 {
 809         struct ref_list *list, *packed_ref_list;
 810         int fd;
 811         int found = 0;
 812
 813         packed_ref_list = get_packed_refs();
 814         for (list = packed_ref_list; list; list = list->next) {
 815                 if (!strcmp(refname, list->name)) {
 816                         found = 1;
 817                         break;
 818                 }
 819         }
 820         if (!found)
 821                 return 0;
 822         fd = hold_lock_file_for_update(&packlock, git_path("packed-refs"), 0);
 823         if (fd < 0)
 824                 return error("cannot delete '%s' from packed refs", refname);
 825
 826         for (list = packed_ref_list; list; list = list->next) {
 827                 char line[PATH_MAX + 100];
 828                 int len;
 829
 830                 if (!strcmp(refname, list->name))
 831                         continue;
 832                 len = snprintf(line, sizeof(line), "%s %s\n",
 833                                sha1_to_hex(list->sha1), list->name);
 834                 /* this should not happen but just being defensive */
 835                 if (len > sizeof(line))
 836                         die("too long a refname '%s'", list->name);
 837                 write_or_die(fd, line, len);
 838         }
 839         close(fd);
 840         return commit_lock_file(&packlock);
 841 }
 842
 843 int delete_ref(const char *refname, const unsigned char *sha1)
 844 {
 845         struct ref_lock *lock;
 846         int err, i, ret = 0, flag = 0;
 847
 848         lock = lock_ref_sha1_basic(refname, sha1, 0, &flag);
 849         if (!lock)
 850                 return 1;
 851         if (!(flag & REF_ISPACKED)) {
 852                 /* loose */
 853                 i = strlen(lock->lk->filename) - 5; /* .lock */
 854                 lock->lk->filename[i] = 0;
 855                 err = unlink(lock->lk->filename);
 856                 if (err) {
 857                         ret = 1;
 858                         error("unlink(%s) failed: %s",
 859                               lock->lk->filename, strerror(errno));
 860                 }
 861                 lock->lk->filename[i] = '.';
 862         }
 863         /* removing the loose one could have resurrected an earlier
 864          * packed one.  Also, if it was not loose we need to repack
 865          * without it.
 866          */
 867         ret |= repack_without_ref(refname);
 868
 869         err = unlink(git_path("logs/%s", lock->ref_name));
 870         if (err && errno != ENOENT)
 871                 fprintf(stderr, "warning: unlink(%s) failed: %s",
 872                         git_path("logs/%s", lock->ref_name), strerror(errno));
 873         invalidate_cached_refs();
 874         unlock_ref(lock);
 875         return ret;
 876 }
 877
 878 int rename_ref(const char *oldref, const char *newref, const char *logmsg)
 879 {
 880         static const char renamed_ref[] = "RENAMED-REF";
 881         unsigned char sha1[20], orig_sha1[20];
 882         int flag = 0, logmoved = 0;
 883         struct ref_lock *lock;
 884         struct stat loginfo;
 885         int log = !lstat(git_path("logs/%s", oldref), &loginfo);
 886
 887         if (S_ISLNK(loginfo.st_mode))
 888                 return error("reflog for %s is a symlink", oldref);
 889
 890         if (!resolve_ref(oldref, orig_sha1, 1, &flag))
 891                 return error("refname %s not found", oldref);
 892
 893         if (!is_refname_available(newref, oldref, get_packed_refs(), 0))
 894                 return 1;
 895
 896         if (!is_refname_available(newref, oldref, get_loose_refs(), 0))
 897                 return 1;
 898
 899         lock = lock_ref_sha1_basic(renamed_ref, NULL, 0, NULL);
 900         if (!lock)
 901                 return error("unable to lock %s", renamed_ref);
 902         lock->force_write = 1;
 903         if (write_ref_sha1(lock, orig_sha1, logmsg))
 904                 return error("unable to save current sha1 in %s", renamed_ref);
 905
 906         if (log && rename(git_path("logs/%s", oldref), git_path("tmp-renamed-log")))
 907                 return error("unable to move logfile logs/%s to tmp-renamed-log: %s",
 908                         oldref, strerror(errno));
 909
 910         if (delete_ref(oldref, orig_sha1)) {
 911                 error("unable to delete old %s", oldref);
 912                 goto rollback;
 913         }
 914
 915         if (resolve_ref(newref, sha1, 1, &flag) && delete_ref(newref, sha1)) {
 916                 if (errno==EISDIR) {
 917                         if (remove_empty_directories(git_path("%s", newref))) {
 918                                 error("Directory not empty: %s", newref);
 919                                 goto rollback;
 920                         }
 921                 } else {
 922                         error("unable to delete existing %s", newref);
 923                         goto rollback;
 924                 }
 925         }
 926
 927         if (log && safe_create_leading_directories(git_path("logs/%s", newref))) {
 928                 error("unable to create directory for %s", newref);
 929                 goto rollback;
 930         }
 931
 932  retry:
 933         if (log && rename(git_path("tmp-renamed-log"), git_path("logs/%s", newref))) {
 934                 if (errno==EISDIR || errno==ENOTDIR) {
 935                         /*
 936                          * rename(a, b) when b is an existing
 937                          * directory ought to result in ISDIR, but
 938                          * Solaris 5.8 gives ENOTDIR.  Sheesh.
 939                          */
 940                         if (remove_empty_directories(git_path("logs/%s", newref))) {
 941                                 error("Directory not empty: logs/%s", newref);
 942                                 goto rollback;
 943                         }
 944                         goto retry;
 945                 } else {
 946                         error("unable to move logfile tmp-renamed-log to logs/%s: %s",
 947                                 newref, strerror(errno));
 948                         goto rollback;
 949                 }
 950         }
 951         logmoved = log;
 952
 953         lock = lock_ref_sha1_basic(newref, NULL, 0, NULL);
 954         if (!lock) {
 955                 error("unable to lock %s for update", newref);
 956                 goto rollback;
 957         }
 958
 959         lock->force_write = 1;
 960         hashcpy(lock->old_sha1, orig_sha1);
 961         if (write_ref_sha1(lock, orig_sha1, logmsg)) {
 962                 error("unable to write current sha1 into %s", newref);
 963                 goto rollback;
 964         }
 965
 966         return 0;
 967
 968  rollback:
 969         lock = lock_ref_sha1_basic(oldref, NULL, 0, NULL);
 970         if (!lock) {
 971                 error("unable to lock %s for rollback", oldref);
 972                 goto rollbacklog;
 973         }
 974
 975         lock->force_write = 1;
 976         flag = log_all_ref_updates;
 977         log_all_ref_updates = 0;
 978         if (write_ref_sha1(lock, orig_sha1, NULL))
 979                 error("unable to write current sha1 into %s", oldref);
 980         log_all_ref_updates = flag;
 981
 982  rollbacklog:
 983         if (logmoved && rename(git_path("logs/%s", newref), git_path("logs/%s", oldref)))
 984                 error("unable to restore logfile %s from %s: %s",
 985                         oldref, newref, strerror(errno));
 986         if (!logmoved && log &&
 987             rename(git_path("tmp-renamed-log"), git_path("logs/%s", oldref)))
 988                 error("unable to restore logfile %s from tmp-renamed-log: %s",
 989                         oldref, strerror(errno));
 990
 991         return 1;
 992 }
 993
 994 void unlock_ref(struct ref_lock *lock)
 995 {
 996         if (lock->lock_fd >= 0) {
 997                 close(lock->lock_fd);
 998                 /* Do not free lock->lk -- atexit() still looks at them */
 999                 if (lock->lk)
1000                         rollback_lock_file(lock->lk);
1001         }
1002         free(lock->ref_name);
1003         free(lock->orig_ref_name);
1004         free(lock);
1005 }
1006
1007 /*
1008  * copy the reflog message msg to buf, which has been allocated sufficiently
1009  * large, while cleaning up the whitespaces.  Especially, convert LF to space,
1010  * because reflog file is one line per entry.
1011  */
1012 static int copy_msg(char *buf, const char *msg)
1013 {
1014         char *cp = buf;
1015         char c;
1016         int wasspace = 1;
1017
1018         *cp++ = '\t';
1019         while ((c = *msg++)) {
1020                 if (wasspace && isspace(c))
1021                         continue;
1022                 wasspace = isspace(c);
1023                 if (wasspace)
1024                         c = ' ';
1025                 *cp++ = c;
1026         }
1027         while (buf < cp && isspace(cp[-1]))
1028                 cp--;
1029         *cp++ = '\n';
1030         return cp - buf;
1031 }
1032
1033 static int log_ref_write(const char *ref_name, const unsigned char *old_sha1,
1034                          const unsigned char *new_sha1, const char *msg)
1035 {
1036         int logfd, written, oflags = O_APPEND | O_WRONLY;
1037         unsigned maxlen, len;
1038         int msglen;
1039         char *log_file, *logrec;
1040         const char *committer;
1041
1042         if (log_all_ref_updates < 0)
1043                 log_all_ref_updates = !is_bare_repository();
1044
1045         log_file = git_path("logs/%s", ref_name);
1046
1047         if (log_all_ref_updates &&
1048             (!prefixcmp(ref_name, "refs/heads/") ||
1049              !prefixcmp(ref_name, "refs/remotes/") ||
1050              !strcmp(ref_name, "HEAD"))) {
1051                 if (safe_create_leading_directories(log_file) < 0)
1052                         return error("unable to create directory for %s",
1053                                      log_file);
1054                 oflags |= O_CREAT;
1055         }
1056
1057         logfd = open(log_file, oflags, 0666);
1058         if (logfd < 0) {
1059                 if (!(oflags & O_CREAT) && errno == ENOENT)
1060                         return 0;
1061
1062                 if ((oflags & O_CREAT) && errno == EISDIR) {
1063                         if (remove_empty_directories(log_file)) {
1064                                 return error("There are still logs under '%s'",
1065                                              log_file);
1066                         }
1067                         logfd = open(log_file, oflags, 0666);
1068                 }
1069
1070                 if (logfd < 0)
1071                         return error("Unable to append to %s: %s",
1072                                      log_file, strerror(errno));
1073         }
1074
1075         adjust_shared_perm(log_file);
1076
1077         msglen = msg ? strlen(msg) : 0;
1078         committer = git_committer_info(-1);
1079         maxlen = strlen(committer) + msglen + 100;
1080         logrec = xmalloc(maxlen);
1081         len = sprintf(logrec, "%s %s %s\n",
1082                       sha1_to_hex(old_sha1),
1083                       sha1_to_hex(new_sha1),
1084                       committer);
1085         if (msglen)
1086                 len += copy_msg(logrec + len - 1, msg) - 1;
1087         written = len <= maxlen ? write_in_full(logfd, logrec, len) : -1;
1088         free(logrec);
1089         if (close(logfd) != 0 || written != len)
1090                 return error("Unable to append to %s", log_file);
1091         return 0;
1092 }
1093
1094 int write_ref_sha1(struct ref_lock *lock,
1095         const unsigned char *sha1, const char *logmsg)
1096 {
1097         static char term = '\n';
1098
1099         if (!lock)
1100                 return -1;
1101         if (!lock->force_write && !hashcmp(lock->old_sha1, sha1)) {
1102                 unlock_ref(lock);
1103                 return 0;
1104         }
1105         if (write_in_full(lock->lock_fd, sha1_to_hex(sha1), 40) != 40 ||
1106             write_in_full(lock->lock_fd, &term, 1) != 1
1107                 || close(lock->lock_fd) < 0) {
1108                 error("Couldn't write %s", lock->lk->filename);
1109                 unlock_ref(lock);
1110                 return -1;
1111         }
1112         invalidate_cached_refs();
1113         if (log_ref_write(lock->ref_name, lock->old_sha1, sha1, logmsg) < 0 ||
1114             (strcmp(lock->ref_name, lock->orig_ref_name) &&
1115              log_ref_write(lock->orig_ref_name, lock->old_sha1, sha1, logmsg) < 0)) {
1116                 unlock_ref(lock);
1117                 return -1;
1118         }
1119         if (strcmp(lock->orig_ref_name, "HEAD") != 0) {
1120                 /*
1121                  * Special hack: If a branch is updated directly and HEAD
1122                  * points to it (may happen on the remote side of a push
1123                  * for example) then logically the HEAD reflog should be
1124                  * updated too.
1125                  * A generic solution implies reverse symref information,
1126                  * but finding all symrefs pointing to the given branch
1127                  * would be rather costly for this rare event (the direct
1128                  * update of a branch) to be worth it.  So let's cheat and
1129                  * check with HEAD only which should cover 99% of all usage
1130                  * scenarios (even 100% of the default ones).
1131                  */
1132                 unsigned char head_sha1[20];
1133                 int head_flag;
1134                 const char *head_ref;
1135                 head_ref = resolve_ref("HEAD", head_sha1, 1, &head_flag);
1136                 if (head_ref && (head_flag & REF_ISSYMREF) &&
1137                     !strcmp(head_ref, lock->ref_name))
1138                         log_ref_write("HEAD", lock->old_sha1, sha1, logmsg);
1139         }
1140         if (commit_lock_file(lock->lk)) {
1141                 error("Couldn't set %s", lock->ref_name);
1142                 unlock_ref(lock);
1143                 return -1;
1144         }
1145         lock->lock_fd = -1;
1146         unlock_ref(lock);
1147         return 0;
1148 }
1149
1150 int create_symref(const char *ref_target, const char *refs_heads_master,
1151                   const char *logmsg)
1152 {
1153         const char *lockpath;
1154         char ref[1000];
1155         int fd, len, written;
1156         char *git_HEAD = xstrdup(git_path("%s", ref_target));
1157         unsigned char old_sha1[20], new_sha1[20];
1158
1159         if (logmsg && read_ref(ref_target, old_sha1))
1160                 hashclr(old_sha1);
1161
1162         if (safe_create_leading_directories(git_HEAD) < 0)
1163                 return error("unable to create directory for %s", git_HEAD);
1164
1165 #ifndef NO_SYMLINK_HEAD
1166         if (prefer_symlink_refs) {
1167                 unlink(git_HEAD);
1168                 if (!symlink(refs_heads_master, git_HEAD))
1169                         goto done;
1170                 fprintf(stderr, "no symlink - falling back to symbolic ref\n");
1171         }
1172 #endif
1173
1174         len = snprintf(ref, sizeof(ref), "ref: %s\n", refs_heads_master);
1175         if (sizeof(ref) <= len) {
1176                 error("refname too long: %s", refs_heads_master);
1177                 goto error_free_return;
1178         }
1179         lockpath = mkpath("%s.lock", git_HEAD);
1180         fd = open(lockpath, O_CREAT | O_EXCL | O_WRONLY, 0666);
1181         if (fd < 0) {
1182                 error("Unable to open %s for writing", lockpath);
1183                 goto error_free_return;
1184         }
1185         written = write_in_full(fd, ref, len);
1186         if (close(fd) != 0 || written != len) {
1187                 error("Unable to write to %s", lockpath);
1188                 goto error_unlink_return;
1189         }
1190         if (rename(lockpath, git_HEAD) < 0) {
1191                 error("Unable to create %s", git_HEAD);
1192                 goto error_unlink_return;
1193         }
1194         if (adjust_shared_perm(git_HEAD)) {
1195                 error("Unable to fix permissions on %s", lockpath);
1196         error_unlink_return:
1197                 unlink(lockpath);
1198         error_free_return:
1199                 free(git_HEAD);
1200                 return -1;
1201         }
1202
1203 #ifndef NO_SYMLINK_HEAD
1204         done:
1205 #endif
1206         if (logmsg && !read_ref(refs_heads_master, new_sha1))
1207                 log_ref_write(ref_target, old_sha1, new_sha1, logmsg);
1208
1209         free(git_HEAD);
1210         return 0;
1211 }
1212
1213 static char *ref_msg(const char *line, const char *endp)
1214 {
1215         const char *ep;
1216         line += 82;
1217         ep = memchr(line, '\n', endp - line);
1218         if (!ep)
1219                 ep = endp;
1220         return xmemdupz(line, ep - line);
1221 }
1222
1223 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)
1224 {
1225         const char *logfile, *logdata, *logend, *rec, *lastgt, *lastrec;
1226         char *tz_c;
1227         int logfd, tz, reccnt = 0;
1228         struct stat st;
1229         unsigned long date;
1230         unsigned char logged_sha1[20];
1231         void *log_mapped;
1232         size_t mapsz;
1233
1234         logfile = git_path("logs/%s", ref);
1235         logfd = open(logfile, O_RDONLY, 0);
1236         if (logfd < 0)
1237                 die("Unable to read log %s: %s", logfile, strerror(errno));
1238         fstat(logfd, &st);
1239         if (!st.st_size)
1240                 die("Log %s is empty.", logfile);
1241         mapsz = xsize_t(st.st_size);
1242         log_mapped = xmmap(NULL, mapsz, PROT_READ, MAP_PRIVATE, logfd, 0);
1243         logdata = log_mapped;
1244         close(logfd);
1245
1246         lastrec = NULL;
1247         rec = logend = logdata + st.st_size;
1248         while (logdata < rec) {
1249                 reccnt++;
1250                 if (logdata < rec && *(rec-1) == '\n')
1251                         rec--;
1252                 lastgt = NULL;
1253                 while (logdata < rec && *(rec-1) != '\n') {
1254                         rec--;
1255                         if (*rec == '>')
1256                                 lastgt = rec;
1257                 }
1258                 if (!lastgt)
1259                         die("Log %s is corrupt.", logfile);
1260                 date = strtoul(lastgt + 1, &tz_c, 10);
1261                 if (date <= at_time || cnt == 0) {
1262                         tz = strtoul(tz_c, NULL, 10);
1263                         if (msg)
1264                                 *msg = ref_msg(rec, logend);
1265                         if (cutoff_time)
1266                                 *cutoff_time = date;
1267                         if (cutoff_tz)
1268                                 *cutoff_tz = tz;
1269                         if (cutoff_cnt)
1270                                 *cutoff_cnt = reccnt - 1;
1271                         if (lastrec) {
1272                                 if (get_sha1_hex(lastrec, logged_sha1))
1273                                         die("Log %s is corrupt.", logfile);
1274                                 if (get_sha1_hex(rec + 41, sha1))
1275                                         die("Log %s is corrupt.", logfile);
1276                                 if (hashcmp(logged_sha1, sha1)) {
1277                                         fprintf(stderr,
1278                                                 "warning: Log %s has gap after %s.\n",
1279                                                 logfile, show_date(date, tz, DATE_RFC2822));
1280                                 }
1281                         }
1282                         else if (date == at_time) {
1283                                 if (get_sha1_hex(rec + 41, sha1))
1284                                         die("Log %s is corrupt.", logfile);
1285                         }
1286                         else {
1287                                 if (get_sha1_hex(rec + 41, logged_sha1))
1288                                         die("Log %s is corrupt.", logfile);
1289                                 if (hashcmp(logged_sha1, sha1)) {
1290                                         fprintf(stderr,
1291                                                 "warning: Log %s unexpectedly ended on %s.\n",
1292                                                 logfile, show_date(date, tz, DATE_RFC2822));
1293                                 }
1294                         }
1295                         munmap(log_mapped, mapsz);
1296                         return 0;
1297                 }
1298                 lastrec = rec;
1299                 if (cnt > 0)
1300                         cnt--;
1301         }
1302
1303         rec = logdata;
1304         while (rec < logend && *rec != '>' && *rec != '\n')
1305                 rec++;
1306         if (rec == logend || *rec == '\n')
1307                 die("Log %s is corrupt.", logfile);
1308         date = strtoul(rec + 1, &tz_c, 10);
1309         tz = strtoul(tz_c, NULL, 10);
1310         if (get_sha1_hex(logdata, sha1))
1311                 die("Log %s is corrupt.", logfile);
1312         if (msg)
1313                 *msg = ref_msg(logdata, logend);
1314         munmap(log_mapped, mapsz);
1315
1316         if (cutoff_time)
1317                 *cutoff_time = date;
1318         if (cutoff_tz)
1319                 *cutoff_tz = tz;
1320         if (cutoff_cnt)
1321                 *cutoff_cnt = reccnt;
1322         return 1;
1323 }
1324
1325 int for_each_reflog_ent(const char *ref, each_reflog_ent_fn fn, void *cb_data)
1326 {
1327         const char *logfile;
1328         FILE *logfp;
1329         char buf[1024];
1330         int ret = 0;
1331
1332         logfile = git_path("logs/%s", ref);
1333         logfp = fopen(logfile, "r");
1334         if (!logfp)
1335                 return -1;
1336         while (fgets(buf, sizeof(buf), logfp)) {
1337                 unsigned char osha1[20], nsha1[20];
1338                 char *email_end, *message;
1339                 unsigned long timestamp;
1340                 int len, tz;
1341
1342                 /* old SP new SP name <email> SP time TAB msg LF */
1343                 len = strlen(buf);
1344                 if (len < 83 || buf[len-1] != '\n' ||
1345                     get_sha1_hex(buf, osha1) || buf[40] != ' ' ||
1346                     get_sha1_hex(buf + 41, nsha1) || buf[81] != ' ' ||
1347                     !(email_end = strchr(buf + 82, '>')) ||
1348                     email_end[1] != ' ' ||
1349                     !(timestamp = strtoul(email_end + 2, &message, 10)) ||
1350                     !message || message[0] != ' ' ||
1351                     (message[1] != '+' && message[1] != '-') ||
1352                     !isdigit(message[2]) || !isdigit(message[3]) ||
1353                     !isdigit(message[4]) || !isdigit(message[5]))
1354                         continue; /* corrupt? */
1355                 email_end[1] = '\0';
1356                 tz = strtol(message + 1, NULL, 10);
1357                 if (message[6] != '\t')
1358                         message += 6;
1359                 else
1360                         message += 7;
1361                 ret = fn(osha1, nsha1, buf+82, timestamp, tz, message, cb_data);
1362                 if (ret)
1363                         break;
1364         }
1365         fclose(logfp);
1366         return ret;
1367 }
1368
1369 static int do_for_each_reflog(const char *base, each_ref_fn fn, void *cb_data)
1370 {
1371         DIR *dir = opendir(git_path("logs/%s", base));
1372         int retval = 0;
1373
1374         if (dir) {
1375                 struct dirent *de;
1376                 int baselen = strlen(base);
1377                 char *log = xmalloc(baselen + 257);
1378
1379                 memcpy(log, base, baselen);
1380                 if (baselen && base[baselen-1] != '/')
1381                         log[baselen++] = '/';
1382
1383                 while ((de = readdir(dir)) != NULL) {
1384                         struct stat st;
1385                         int namelen;
1386
1387                         if (de->d_name[0] == '.')
1388                                 continue;
1389                         namelen = strlen(de->d_name);
1390                         if (namelen > 255)
1391                                 continue;
1392                         if (has_extension(de->d_name, ".lock"))
1393                                 continue;
1394                         memcpy(log + baselen, de->d_name, namelen+1);
1395                         if (stat(git_path("logs/%s", log), &st) < 0)
1396                                 continue;
1397                         if (S_ISDIR(st.st_mode)) {
1398                                 retval = do_for_each_reflog(log, fn, cb_data);
1399                         } else {
1400                                 unsigned char sha1[20];
1401                                 if (!resolve_ref(log, sha1, 0, NULL))
1402                                         retval = error("bad ref for %s", log);
1403                                 else
1404                                         retval = fn(log, sha1, 0, cb_data);
1405                         }
1406                         if (retval)
1407                                 break;
1408                 }
1409                 free(log);
1410                 closedir(dir);
1411         }
1412         else if (*base)
1413                 return errno;
1414         return retval;
1415 }
1416
1417 int for_each_reflog(each_ref_fn fn, void *cb_data)
1418 {
1419         return do_for_each_reflog("", fn, cb_data);
1420 }
1421
1422 int update_ref(const char *action, const char *refname,
1423                 const unsigned char *sha1, const unsigned char *oldval,
1424                 int flags, enum action_on_err onerr)
1425 {
1426         static struct ref_lock *lock;
1427         lock = lock_any_ref_for_update(refname, oldval, flags);
1428         if (!lock) {
1429                 const char *str = "Cannot lock the ref '%s'.";
1430                 switch (onerr) {
1431                 case MSG_ON_ERR: error(str, refname); break;
1432                 case DIE_ON_ERR: die(str, refname); break;
1433                 case QUIET_ON_ERR: break;
1434                 }
1435                 return 1;
1436         }
1437         if (write_ref_sha1(lock, sha1, action) < 0) {
1438                 const char *str = "Cannot update the ref '%s'.";
1439                 switch (onerr) {
1440                 case MSG_ON_ERR: error(str, refname); break;
1441                 case DIE_ON_ERR: die(str, refname); break;
1442                 case QUIET_ON_ERR: break;
1443                 }
1444                 return 1;
1445         }
1446         return 0;
1447 }