refs.c

   1 #include "cache.h"
   2 #include "refs.h"
   3 #include "object.h"
   4 #include "tag.h"
   5
   6 /* ISSYMREF=01 and ISPACKED=02 are public interfaces */
   7 #define REF_KNOWS_PEELED 04
   8
   9 struct ref_list {
  10         struct ref_list *next;
  11         unsigned char flag; /* ISSYMREF? ISPACKED? */
  12         unsigned char sha1[20];
  13         unsigned char peeled[20];
  14         char name[FLEX_ARRAY];
  15 };
  16
  17 static const char *parse_ref_line(char *line, unsigned char *sha1)
  18 {
  19         /*
  20          * 42: the answer to everything.
  21          *
  22          * In this case, it happens to be the answer to
  23          *  40 (length of sha1 hex representation)
  24          *  +1 (space in between hex and name)
  25          *  +1 (newline at the end of the line)
  26          */
  27         int len = strlen(line) - 42;
  28
  29         if (len <= 0)
  30                 return NULL;
  31         if (get_sha1_hex(line, sha1) < 0)
  32                 return NULL;
  33         if (!isspace(line[40]))
  34                 return NULL;
  35         line += 41;
  36         if (isspace(*line))
  37                 return NULL;
  38         if (line[len] != '\n')
  39                 return NULL;
  40         line[len] = 0;
  41
  42         return line;
  43 }
  44
  45 static struct ref_list *add_ref(const char *name, const unsigned char *sha1,
  46                                 int flag, struct ref_list *list,
  47                                 struct ref_list **new_entry)
  48 {
  49         int len;
  50         struct ref_list *entry;
  51
  52         /* Allocate it and add it in.. */
  53         len = strlen(name) + 1;
  54         entry = xmalloc(sizeof(struct ref_list) + len);
  55         hashcpy(entry->sha1, sha1);
  56         hashclr(entry->peeled);
  57         memcpy(entry->name, name, len);
  58         entry->flag = flag;
  59         entry->next = list;
  60         if (new_entry)
  61                 *new_entry = entry;
  62         return entry;
  63 }
  64
  65 /* merge sort the ref list */
  66 static struct ref_list *sort_ref_list(struct ref_list *list)
  67 {
  68         int psize, qsize, last_merge_count, cmp;
  69         struct ref_list *p, *q, *l, *e;
  70         struct ref_list *new_list = list;
  71         int k = 1;
  72         int merge_count = 0;
  73
  74         if (!list)
  75                 return list;
  76
  77         do {
  78                 last_merge_count = merge_count;
  79                 merge_count = 0;
  80
  81                 psize = 0;
  82
  83                 p = new_list;
  84                 q = new_list;
  85                 new_list = NULL;
  86                 l = NULL;
  87
  88                 while (p) {
  89                         merge_count++;
  90
  91                         while (psize < k && q->next) {
  92                                 q = q->next;
  93                                 psize++;
  94                         }
  95                         qsize = k;
  96
  97                         while ((psize > 0) || (qsize > 0 && q)) {
  98                                 if (qsize == 0 || !q) {
  99                                         e = p;
 100                                         p = p->next;
 101                                         psize--;
 102                                 } else if (psize == 0) {
 103                                         e = q;
 104                                         q = q->next;
 105                                         qsize--;
 106                                 } else {
 107                                         cmp = strcmp(q->name, p->name);
 108                                         if (cmp < 0) {
 109                                                 e = q;
 110                                                 q = q->next;
 111                                                 qsize--;
 112                                         } else if (cmp > 0) {
 113                                                 e = p;
 114                                                 p = p->next;
 115                                                 psize--;
 116                                         } else {
 117                                                 if (hashcmp(q->sha1, p->sha1))
 118                                                         die("Duplicated ref, and SHA1s don't match: %s",
 119                                                             q->name);
 120                                                 warning("Duplicated ref: %s", q->name);
 121                                                 e = q;
 122                                                 q = q->next;
 123                                                 qsize--;
 124                                                 free(e);
 125                                                 e = p;
 126                                                 p = p->next;
 127                                                 psize--;
 128                                         }
 129                                 }
 130
 131                                 e->next = NULL;
 132
 133                                 if (l)
 134                                         l->next = e;
 135                                 if (!new_list)
 136                                         new_list = e;
 137                                 l = e;
 138                         }
 139
 140                         p = q;
 141                 };
 142
 143                 k = k * 2;
 144         } while ((last_merge_count != merge_count) || (last_merge_count != 1));
 145
 146         return new_list;
 147 }
 148
 149 /*
 150  * Future: need to be in "struct repository"
 151  * when doing a full libification.
 152  */
 153 static struct cached_refs {
 154         char did_loose;
 155         char did_packed;
 156         struct ref_list *loose;
 157         struct ref_list *packed;
 158 } cached_refs;
 159
 160 static void free_ref_list(struct ref_list *list)
 161 {
 162         struct ref_list *next;
 163         for ( ; list; list = next) {
 164                 next = list->next;
 165                 free(list);
 166         }
 167 }
 168
 169 static void invalidate_cached_refs(void)
 170 {
 171         struct cached_refs *ca = &cached_refs;
 172
 173         if (ca->did_loose && ca->loose)
 174                 free_ref_list(ca->loose);
 175         if (ca->did_packed && ca->packed)
 176                 free_ref_list(ca->packed);
 177         ca->loose = ca->packed = NULL;
 178         ca->did_loose = ca->did_packed = 0;
 179 }
 180
 181 static void read_packed_refs(FILE *f, struct cached_refs *cached_refs)
 182 {
 183         struct ref_list *list = NULL;
 184         struct ref_list *last = NULL;
 185         char refline[PATH_MAX];
 186         int flag = REF_ISPACKED;
 187
 188         while (fgets(refline, sizeof(refline), f)) {
 189                 unsigned char sha1[20];
 190                 const char *name;
 191                 static const char header[] = "# pack-refs with:";
 192
 193                 if (!strncmp(refline, header, sizeof(header)-1)) {
 194                         const char *traits = refline + sizeof(header) - 1;
 195                         if (strstr(traits, " peeled "))
 196                                 flag |= REF_KNOWS_PEELED;
 197                         /* perhaps other traits later as well */
 198                         continue;
 199                 }
 200
 201                 name = parse_ref_line(refline, sha1);
 202                 if (name) {
 203                         list = add_ref(name, sha1, flag, list, &last);
 204                         continue;
 205                 }
 206                 if (last &&
 207                     refline[0] == '^' &&
 208                     strlen(refline) == 42 &&
 209                     refline[41] == '\n' &&
 210                     !get_sha1_hex(refline + 1, sha1))
 211                         hashcpy(last->peeled, sha1);
 212         }
 213         cached_refs->packed = sort_ref_list(list);
 214 }
 215
 216 static struct ref_list *get_packed_refs(void)
 217 {
 218         if (!cached_refs.did_packed) {
 219                 FILE *f = fopen(git_path("packed-refs"), "r");
 220                 cached_refs.packed = NULL;
 221                 if (f) {
 222                         read_packed_refs(f, &cached_refs);
 223                         fclose(f);
 224                 }
 225                 cached_refs.did_packed = 1;
 226         }
 227         return cached_refs.packed;
 228 }
 229
 230 static struct ref_list *get_ref_dir(const char *base, struct ref_list *list)
 231 {
 232         DIR *dir = opendir(git_path("%s", base));
 233
 234         if (dir) {
 235                 struct dirent *de;
 236                 int baselen = strlen(base);
 237                 char *ref = xmalloc(baselen + 257);
 238
 239                 memcpy(ref, base, baselen);
 240                 if (baselen && base[baselen-1] != '/')
 241                         ref[baselen++] = '/';
 242
 243                 while ((de = readdir(dir)) != NULL) {
 244                         unsigned char sha1[20];
 245                         struct stat st;
 246                         int flag;
 247                         int namelen;
 248
 249                         if (de->d_name[0] == '.')
 250                                 continue;
 251                         namelen = strlen(de->d_name);
 252                         if (namelen > 255)
 253                                 continue;
 254                         if (has_extension(de->d_name, ".lock"))
 255                                 continue;
 256                         memcpy(ref + baselen, de->d_name, namelen+1);
 257                         if (stat(git_path("%s", ref), &st) < 0)
 258                                 continue;
 259                         if (S_ISDIR(st.st_mode)) {
 260                                 list = get_ref_dir(ref, list);
 261                                 continue;
 262                         }
 263                         if (!resolve_ref(ref, sha1, 1, &flag)) {
 264                                 error("%s points nowhere!", ref);
 265                                 continue;
 266                         }
 267                         list = add_ref(ref, sha1, flag, list, NULL);
 268                 }
 269                 free(ref);
 270                 closedir(dir);
 271         }
 272         return sort_ref_list(list);
 273 }
 274
 275 static struct ref_list *get_loose_refs(void)
 276 {
 277         if (!cached_refs.did_loose) {
 278                 cached_refs.loose = get_ref_dir("refs", NULL);
 279                 cached_refs.did_loose = 1;
 280         }
 281         return cached_refs.loose;
 282 }
 283
 284 /* We allow "recursive" symbolic refs. Only within reason, though */
 285 #define MAXDEPTH 5
 286 #define MAXREFLEN (1024)
 287
 288 static int resolve_gitlink_packed_ref(char *name, int pathlen, const char *refname, unsigned char *result)
 289 {
 290         FILE *f;
 291         struct cached_refs refs;
 292         struct ref_list *ref;
 293         int retval;
 294
 295         strcpy(name + pathlen, "packed-refs");
 296         f = fopen(name, "r");
 297         if (!f)
 298                 return -1;
 299         read_packed_refs(f, &refs);
 300         fclose(f);
 301         ref = refs.packed;
 302         retval = -1;
 303         while (ref) {
 304                 if (!strcmp(ref->name, refname)) {
 305                         retval = 0;
 306                         memcpy(result, ref->sha1, 20);
 307                         break;
 308                 }
 309                 ref = ref->next;
 310         }
 311         free_ref_list(refs.packed);
 312         return retval;
 313 }
 314
 315 static int resolve_gitlink_ref_recursive(char *name, int pathlen, const char *refname, unsigned char *result, int recursion)
 316 {
 317         int fd, len = strlen(refname);
 318         char buffer[128], *p;
 319
 320         if (recursion > MAXDEPTH || len > MAXREFLEN)
 321                 return -1;
 322         memcpy(name + pathlen, refname, len+1);
 323         fd = open(name, O_RDONLY);
 324         if (fd < 0)
 325                 return resolve_gitlink_packed_ref(name, pathlen, refname, result);
 326
 327         len = read(fd, buffer, sizeof(buffer)-1);
 328         close(fd);
 329         if (len < 0)
 330                 return -1;
 331         while (len && isspace(buffer[len-1]))
 332                 len--;
 333         buffer[len] = 0;
 334
 335         /* Was it a detached head or an old-fashioned symlink? */
 336         if (!get_sha1_hex(buffer, result))
 337                 return 0;
 338
 339         /* Symref? */
 340         if (strncmp(buffer, "ref:", 4))
 341                 return -1;
 342         p = buffer + 4;
 343         while (isspace(*p))
 344                 p++;
 345
 346         return resolve_gitlink_ref_recursive(name, pathlen, p, result, recursion+1);
 347 }
 348
 349 int resolve_gitlink_ref(const char *path, const char *refname, unsigned char *result)
 350 {
 351         int len = strlen(path), retval;
 352         char *gitdir;
 353
 354         while (len && path[len-1] == '/')
 355                 len--;
 356         if (!len)
 357                 return -1;
 358         gitdir = xmalloc(len + MAXREFLEN + 8);
 359         memcpy(gitdir, path, len);
 360         memcpy(gitdir + len, "/.git/", 7);
 361
 362         retval = resolve_gitlink_ref_recursive(gitdir, len+6, refname, result, 0);
 363         free(gitdir);
 364         return retval;
 365 }
 366
 367 const char *resolve_ref(const char *ref, unsigned char *sha1, int reading, int *flag)
 368 {
 369         int depth = MAXDEPTH, len;
 370         char buffer[256];
 371         static char ref_buffer[256];
 372
 373         if (flag)
 374                 *flag = 0;
 375
 376         for (;;) {
 377                 const char *path = git_path("%s", ref);
 378                 struct stat st;
 379                 char *buf;
 380                 int fd;
 381
 382                 if (--depth < 0)
 383                         return NULL;
 384
 385                 /* Special case: non-existing file.
 386                  * Not having the refs/heads/new-branch is OK
 387                  * if we are writing into it, so is .git/HEAD
 388                  * that points at refs/heads/master still to be
 389                  * born.  It is NOT OK if we are resolving for
 390                  * reading.
 391                  */
 392                 if (lstat(path, &st) < 0) {
 393                         struct ref_list *list = get_packed_refs();
 394                         while (list) {
 395                                 if (!strcmp(ref, list->name)) {
 396                                         hashcpy(sha1, list->sha1);
 397                                         if (flag)
 398                                                 *flag |= REF_ISPACKED;
 399                                         return ref;
 400                                 }
 401                                 list = list->next;
 402                         }
 403                         if (reading || errno != ENOENT)
 404                                 return NULL;
 405                         hashclr(sha1);
 406                         return ref;
 407                 }
 408
 409                 /* Follow "normalized" - ie "refs/.." symlinks by hand */
 410                 if (S_ISLNK(st.st_mode)) {
 411                         len = readlink(path, buffer, sizeof(buffer)-1);
 412                         if (len >= 5 && !memcmp("refs/", buffer, 5)) {
 413                                 buffer[len] = 0;
 414                                 strcpy(ref_buffer, buffer);
 415                                 ref = ref_buffer;
 416                                 if (flag)
 417                                         *flag |= REF_ISSYMREF;
 418                                 continue;
 419                         }
 420                 }
 421
 422                 /* Is it a directory? */
 423                 if (S_ISDIR(st.st_mode)) {
 424                         errno = EISDIR;
 425                         return NULL;
 426                 }
 427
 428                 /*
 429                  * Anything else, just open it and try to use it as
 430                  * a ref
 431                  */
 432                 fd = open(path, O_RDONLY);
 433                 if (fd < 0)
 434                         return NULL;
 435                 len = read_in_full(fd, buffer, sizeof(buffer)-1);
 436                 close(fd);
 437
 438                 /*
 439                  * Is it a symbolic ref?
 440                  */
 441                 if (len < 4 || memcmp("ref:", buffer, 4))
 442                         break;
 443                 buf = buffer + 4;
 444                 len -= 4;
 445                 while (len && isspace(*buf))
 446                         buf++, len--;
 447                 while (len && isspace(buf[len-1]))
 448                         len--;
 449                 buf[len] = 0;
 450                 memcpy(ref_buffer, buf, len + 1);
 451                 ref = ref_buffer;
 452                 if (flag)
 453                         *flag |= REF_ISSYMREF;
 454         }
 455         if (len < 40 || get_sha1_hex(buffer, sha1))
 456                 return NULL;
 457         return ref;
 458 }
 459
 460 int read_ref(const char *ref, unsigned char *sha1)
 461 {
 462         if (resolve_ref(ref, sha1, 1, NULL))
 463                 return 0;
 464         return -1;
 465 }
 466
 467 static int do_one_ref(const char *base, each_ref_fn fn, int trim,
 468                       void *cb_data, struct ref_list *entry)
 469 {
 470         if (strncmp(base, entry->name, trim))
 471                 return 0;
 472         if (is_null_sha1(entry->sha1))
 473                 return 0;
 474         if (!has_sha1_file(entry->sha1)) {
 475                 error("%s does not point to a valid object!", entry->name);
 476                 return 0;
 477         }
 478         return fn(entry->name + trim, entry->sha1, entry->flag, cb_data);
 479 }
 480
 481 int peel_ref(const char *ref, unsigned char *sha1)
 482 {
 483         int flag;
 484         unsigned char base[20];
 485         struct object *o;
 486
 487         if (!resolve_ref(ref, base, 1, &flag))
 488                 return -1;
 489
 490         if ((flag & REF_ISPACKED)) {
 491                 struct ref_list *list = get_packed_refs();
 492
 493                 while (list) {
 494                         if (!strcmp(list->name, ref)) {
 495                                 if (list->flag & REF_KNOWS_PEELED) {
 496                                         hashcpy(sha1, list->peeled);
 497                                         return 0;
 498                                 }
 499                                 /* older pack-refs did not leave peeled ones */
 500                                 break;
 501                         }
 502                         list = list->next;
 503                 }
 504         }
 505
 506         /* fallback - callers should not call this for unpacked refs */
 507         o = parse_object(base);
 508         if (o->type == OBJ_TAG) {
 509                 o = deref_tag(o, ref, 0);
 510                 if (o) {
 511                         hashcpy(sha1, o->sha1);
 512                         return 0;
 513                 }
 514         }
 515         return -1;
 516 }
 517
 518 static int do_for_each_ref(const char *base, each_ref_fn fn, int trim,
 519                            void *cb_data)
 520 {
 521         int retval;
 522         struct ref_list *packed = get_packed_refs();
 523         struct ref_list *loose = get_loose_refs();
 524
 525         while (packed && loose) {
 526                 struct ref_list *entry;
 527                 int cmp = strcmp(packed->name, loose->name);
 528                 if (!cmp) {
 529                         packed = packed->next;
 530                         continue;
 531                 }
 532                 if (cmp > 0) {
 533                         entry = loose;
 534                         loose = loose->next;
 535                 } else {
 536                         entry = packed;
 537                         packed = packed->next;
 538                 }
 539                 retval = do_one_ref(base, fn, trim, cb_data, entry);
 540                 if (retval)
 541                         return retval;
 542         }
 543
 544         for (packed = packed ? packed : loose; packed; packed = packed->next) {
 545                 retval = do_one_ref(base, fn, trim, cb_data, packed);
 546                 if (retval)
 547                         return retval;
 548         }
 549         return 0;
 550 }
 551
 552 int head_ref(each_ref_fn fn, void *cb_data)
 553 {
 554         unsigned char sha1[20];
 555         int flag;
 556
 557         if (resolve_ref("HEAD", sha1, 1, &flag))
 558                 return fn("HEAD", sha1, flag, cb_data);
 559         return 0;
 560 }
 561
 562 int for_each_ref(each_ref_fn fn, void *cb_data)
 563 {
 564         return do_for_each_ref("refs/", fn, 0, cb_data);
 565 }
 566
 567 int for_each_tag_ref(each_ref_fn fn, void *cb_data)
 568 {
 569         return do_for_each_ref("refs/tags/", fn, 10, cb_data);
 570 }
 571
 572 int for_each_branch_ref(each_ref_fn fn, void *cb_data)
 573 {
 574         return do_for_each_ref("refs/heads/", fn, 11, cb_data);
 575 }
 576
 577 int for_each_remote_ref(each_ref_fn fn, void *cb_data)
 578 {
 579         return do_for_each_ref("refs/remotes/", fn, 13, cb_data);
 580 }
 581
 582 /* NEEDSWORK: This is only used by ssh-upload and it should go; the
 583  * caller should do resolve_ref or read_ref like everybody else.  Or
 584  * maybe everybody else should use get_ref_sha1() instead of doing
 585  * read_ref().
 586  */
 587 int get_ref_sha1(const char *ref, unsigned char *sha1)
 588 {
 589         if (check_ref_format(ref))
 590                 return -1;
 591         return read_ref(mkpath("refs/%s", ref), sha1);
 592 }
 593
 594 /*
 595  * Make sure "ref" is something reasonable to have under ".git/refs/";
 596  * We do not like it if:
 597  *
 598  * - any path component of it begins with ".", or
 599  * - it has double dots "..", or
 600  * - it has ASCII control character, "~", "^", ":" or SP, anywhere, or
 601  * - it ends with a "/".
 602  */
 603
 604 static inline int bad_ref_char(int ch)
 605 {
 606         if (((unsigned) ch) <= ' ' ||
 607             ch == '~' || ch == '^' || ch == ':')
 608                 return 1;
 609         /* 2.13 Pattern Matching Notation */
 610         if (ch == '?' || ch == '[') /* Unsupported */
 611                 return 1;
 612         if (ch == '*') /* Supported at the end */
 613                 return 2;
 614         return 0;
 615 }
 616
 617 int check_ref_format(const char *ref)
 618 {
 619         int ch, level, bad_type;
 620         const char *cp = ref;
 621
 622         level = 0;
 623         while (1) {
 624                 while ((ch = *cp++) == '/')
 625                         ; /* tolerate duplicated slashes */
 626                 if (!ch)
 627                         return -1; /* should not end with slashes */
 628
 629                 /* we are at the beginning of the path component */
 630                 if (ch == '.')
 631                         return -1;
 632                 bad_type = bad_ref_char(ch);
 633                 if (bad_type) {
 634                         return (bad_type == 2 && !*cp) ? -3 : -1;
 635                 }
 636
 637                 /* scan the rest of the path component */
 638                 while ((ch = *cp++) != 0) {
 639                         bad_type = bad_ref_char(ch);
 640                         if (bad_type) {
 641                                 return (bad_type == 2 && !*cp) ? -3 : -1;
 642                         }
 643                         if (ch == '/')
 644                                 break;
 645                         if (ch == '.' && *cp == '.')
 646                                 return -1;
 647                 }
 648                 level++;
 649                 if (!ch) {
 650                         if (level < 2)
 651                                 return -2; /* at least of form "heads/blah" */
 652                         return 0;
 653                 }
 654         }
 655 }
 656
 657 static struct ref_lock *verify_lock(struct ref_lock *lock,
 658         const unsigned char *old_sha1, int mustexist)
 659 {
 660         if (!resolve_ref(lock->ref_name, lock->old_sha1, mustexist, NULL)) {
 661                 error("Can't verify ref %s", lock->ref_name);
 662                 unlock_ref(lock);
 663                 return NULL;
 664         }
 665         if (hashcmp(lock->old_sha1, old_sha1)) {
 666                 error("Ref %s is at %s but expected %s", lock->ref_name,
 667                         sha1_to_hex(lock->old_sha1), sha1_to_hex(old_sha1));
 668                 unlock_ref(lock);
 669                 return NULL;
 670         }
 671         return lock;
 672 }
 673
 674 static int remove_empty_dir_recursive(char *path, int len)
 675 {
 676         DIR *dir = opendir(path);
 677         struct dirent *e;
 678         int ret = 0;
 679
 680         if (!dir)
 681                 return -1;
 682         if (path[len-1] != '/')
 683                 path[len++] = '/';
 684         while ((e = readdir(dir)) != NULL) {
 685                 struct stat st;
 686                 int namlen;
 687                 if ((e->d_name[0] == '.') &&
 688                     ((e->d_name[1] == 0) ||
 689                      ((e->d_name[1] == '.') && e->d_name[2] == 0)))
 690                         continue; /* "." and ".." */
 691
 692                 namlen = strlen(e->d_name);
 693                 if ((len + namlen < PATH_MAX) &&
 694                     strcpy(path + len, e->d_name) &&
 695                     !lstat(path, &st) &&
 696                     S_ISDIR(st.st_mode) &&
 697                     !remove_empty_dir_recursive(path, len + namlen))
 698                         continue; /* happy */
 699
 700                 /* path too long, stat fails, or non-directory still exists */
 701                 ret = -1;
 702                 break;
 703         }
 704         closedir(dir);
 705         if (!ret) {
 706                 path[len] = 0;
 707                 ret = rmdir(path);
 708         }
 709         return ret;
 710 }
 711
 712 static int remove_empty_directories(char *file)
 713 {
 714         /* we want to create a file but there is a directory there;
 715          * if that is an empty directory (or a directory that contains
 716          * only empty directories), remove them.
 717          */
 718         char path[PATH_MAX];
 719         int len = strlen(file);
 720
 721         if (len >= PATH_MAX) /* path too long ;-) */
 722                 return -1;
 723         strcpy(path, file);
 724         return remove_empty_dir_recursive(path, len);
 725 }
 726
 727 static int is_refname_available(const char *ref, const char *oldref,
 728                                 struct ref_list *list, int quiet)
 729 {
 730         int namlen = strlen(ref); /* e.g. 'foo/bar' */
 731         while (list) {
 732                 /* list->name could be 'foo' or 'foo/bar/baz' */
 733                 if (!oldref || strcmp(oldref, list->name)) {
 734                         int len = strlen(list->name);
 735                         int cmplen = (namlen < len) ? namlen : len;
 736                         const char *lead = (namlen < len) ? list->name : ref;
 737                         if (!strncmp(ref, list->name, cmplen) &&
 738                             lead[cmplen] == '/') {
 739                                 if (!quiet)
 740                                         error("'%s' exists; cannot create '%s'",
 741                                               list->name, ref);
 742                                 return 0;
 743                         }
 744                 }
 745                 list = list->next;
 746         }
 747         return 1;
 748 }
 749
 750 static struct ref_lock *lock_ref_sha1_basic(const char *ref, const unsigned char *old_sha1, int flags, int *type_p)
 751 {
 752         char *ref_file;
 753         const char *orig_ref = ref;
 754         struct ref_lock *lock;
 755         struct stat st;
 756         int last_errno = 0;
 757         int type;
 758         int mustexist = (old_sha1 && !is_null_sha1(old_sha1));
 759
 760         lock = xcalloc(1, sizeof(struct ref_lock));
 761         lock->lock_fd = -1;
 762
 763         ref = resolve_ref(ref, lock->old_sha1, mustexist, &type);
 764         if (!ref && errno == EISDIR) {
 765                 /* we are trying to lock foo but we used to
 766                  * have foo/bar which now does not exist;
 767                  * it is normal for the empty directory 'foo'
 768                  * to remain.
 769                  */
 770                 ref_file = git_path("%s", orig_ref);
 771                 if (remove_empty_directories(ref_file)) {
 772                         last_errno = errno;
 773                         error("there are still refs under '%s'", orig_ref);
 774                         goto error_return;
 775                 }
 776                 ref = resolve_ref(orig_ref, lock->old_sha1, mustexist, &type);
 777         }
 778         if (type_p)
 779             *type_p = type;
 780         if (!ref) {
 781                 last_errno = errno;
 782                 error("unable to resolve reference %s: %s",
 783                         orig_ref, strerror(errno));
 784                 goto error_return;
 785         }
 786         /* When the ref did not exist and we are creating it,
 787          * make sure there is no existing ref that is packed
 788          * whose name begins with our refname, nor a ref whose
 789          * name is a proper prefix of our refname.
 790          */
 791         if (is_null_sha1(lock->old_sha1) &&
 792             !is_refname_available(ref, NULL, get_packed_refs(), 0))
 793                 goto error_return;
 794
 795         lock->lk = xcalloc(1, sizeof(struct lock_file));
 796
 797         if (flags & REF_NODEREF)
 798                 ref = orig_ref;
 799         lock->ref_name = xstrdup(ref);
 800         lock->orig_ref_name = xstrdup(orig_ref);
 801         ref_file = git_path("%s", ref);
 802         if (lstat(ref_file, &st) && errno == ENOENT)
 803                 lock->force_write = 1;
 804         if ((flags & REF_NODEREF) && (type & REF_ISSYMREF))
 805                 lock->force_write = 1;
 806
 807         if (safe_create_leading_directories(ref_file)) {
 808                 last_errno = errno;
 809                 error("unable to create directory for %s", ref_file);
 810                 goto error_return;
 811         }
 812         lock->lock_fd = hold_lock_file_for_update(lock->lk, ref_file, 1);
 813
 814         return old_sha1 ? verify_lock(lock, old_sha1, mustexist) : lock;
 815
 816  error_return:
 817         unlock_ref(lock);
 818         errno = last_errno;
 819         return NULL;
 820 }
 821
 822 struct ref_lock *lock_ref_sha1(const char *ref, const unsigned char *old_sha1)
 823 {
 824         char refpath[PATH_MAX];
 825         if (check_ref_format(ref))
 826                 return NULL;
 827         strcpy(refpath, mkpath("refs/%s", ref));
 828         return lock_ref_sha1_basic(refpath, old_sha1, 0, NULL);
 829 }
 830
 831 struct ref_lock *lock_any_ref_for_update(const char *ref, const unsigned char *old_sha1, int flags)
 832 {
 833         if (check_ref_format(ref) == -1)
 834                 return NULL;
 835         return lock_ref_sha1_basic(ref, old_sha1, flags, NULL);
 836 }
 837
 838 static struct lock_file packlock;
 839
 840 static int repack_without_ref(const char *refname)
 841 {
 842         struct ref_list *list, *packed_ref_list;
 843         int fd;
 844         int found = 0;
 845
 846         packed_ref_list = get_packed_refs();
 847         for (list = packed_ref_list; list; list = list->next) {
 848                 if (!strcmp(refname, list->name)) {
 849                         found = 1;
 850                         break;
 851                 }
 852         }
 853         if (!found)
 854                 return 0;
 855         fd = hold_lock_file_for_update(&packlock, git_path("packed-refs"), 0);
 856         if (fd < 0)
 857                 return error("cannot delete '%s' from packed refs", refname);
 858
 859         for (list = packed_ref_list; list; list = list->next) {
 860                 char line[PATH_MAX + 100];
 861                 int len;
 862
 863                 if (!strcmp(refname, list->name))
 864                         continue;
 865                 len = snprintf(line, sizeof(line), "%s %s\n",
 866                                sha1_to_hex(list->sha1), list->name);
 867                 /* this should not happen but just being defensive */
 868                 if (len > sizeof(line))
 869                         die("too long a refname '%s'", list->name);
 870                 write_or_die(fd, line, len);
 871         }
 872         close(fd);
 873         return commit_lock_file(&packlock);
 874 }
 875
 876 int delete_ref(const char *refname, const unsigned char *sha1)
 877 {
 878         struct ref_lock *lock;
 879         int err, i, ret = 0, flag = 0;
 880
 881         lock = lock_ref_sha1_basic(refname, sha1, 0, &flag);
 882         if (!lock)
 883                 return 1;
 884         if (!(flag & REF_ISPACKED)) {
 885                 /* loose */
 886                 i = strlen(lock->lk->filename) - 5; /* .lock */
 887                 lock->lk->filename[i] = 0;
 888                 err = unlink(lock->lk->filename);
 889                 if (err) {
 890                         ret = 1;
 891                         error("unlink(%s) failed: %s",
 892                               lock->lk->filename, strerror(errno));
 893                 }
 894                 lock->lk->filename[i] = '.';
 895         }
 896         /* removing the loose one could have resurrected an earlier
 897          * packed one.  Also, if it was not loose we need to repack
 898          * without it.
 899          */
 900         ret |= repack_without_ref(refname);
 901
 902         err = unlink(git_path("logs/%s", lock->ref_name));
 903         if (err && errno != ENOENT)
 904                 fprintf(stderr, "warning: unlink(%s) failed: %s",
 905                         git_path("logs/%s", lock->ref_name), strerror(errno));
 906         invalidate_cached_refs();
 907         unlock_ref(lock);
 908         return ret;
 909 }
 910
 911 int rename_ref(const char *oldref, const char *newref, const char *logmsg)
 912 {
 913         static const char renamed_ref[] = "RENAMED-REF";
 914         unsigned char sha1[20], orig_sha1[20];
 915         int flag = 0, logmoved = 0;
 916         struct ref_lock *lock;
 917         struct stat loginfo;
 918         int log = !lstat(git_path("logs/%s", oldref), &loginfo);
 919
 920         if (S_ISLNK(loginfo.st_mode))
 921                 return error("reflog for %s is a symlink", oldref);
 922
 923         if (!resolve_ref(oldref, orig_sha1, 1, &flag))
 924                 return error("refname %s not found", oldref);
 925
 926         if (!is_refname_available(newref, oldref, get_packed_refs(), 0))
 927                 return 1;
 928
 929         if (!is_refname_available(newref, oldref, get_loose_refs(), 0))
 930                 return 1;
 931
 932         lock = lock_ref_sha1_basic(renamed_ref, NULL, 0, NULL);
 933         if (!lock)
 934                 return error("unable to lock %s", renamed_ref);
 935         lock->force_write = 1;
 936         if (write_ref_sha1(lock, orig_sha1, logmsg))
 937                 return error("unable to save current sha1 in %s", renamed_ref);
 938
 939         if (log && rename(git_path("logs/%s", oldref), git_path("tmp-renamed-log")))
 940                 return error("unable to move logfile logs/%s to tmp-renamed-log: %s",
 941                         oldref, strerror(errno));
 942
 943         if (delete_ref(oldref, orig_sha1)) {
 944                 error("unable to delete old %s", oldref);
 945                 goto rollback;
 946         }
 947
 948         if (resolve_ref(newref, sha1, 1, &flag) && delete_ref(newref, sha1)) {
 949                 if (errno==EISDIR) {
 950                         if (remove_empty_directories(git_path("%s", newref))) {
 951                                 error("Directory not empty: %s", newref);
 952                                 goto rollback;
 953                         }
 954                 } else {
 955                         error("unable to delete existing %s", newref);
 956                         goto rollback;
 957                 }
 958         }
 959
 960         if (log && safe_create_leading_directories(git_path("logs/%s", newref))) {
 961                 error("unable to create directory for %s", newref);
 962                 goto rollback;
 963         }
 964
 965  retry:
 966         if (log && rename(git_path("tmp-renamed-log"), git_path("logs/%s", newref))) {
 967                 if (errno==EISDIR || errno==ENOTDIR) {
 968                         /*
 969                          * rename(a, b) when b is an existing
 970                          * directory ought to result in ISDIR, but
 971                          * Solaris 5.8 gives ENOTDIR.  Sheesh.
 972                          */
 973                         if (remove_empty_directories(git_path("logs/%s", newref))) {
 974                                 error("Directory not empty: logs/%s", newref);
 975                                 goto rollback;
 976                         }
 977                         goto retry;
 978                 } else {
 979                         error("unable to move logfile tmp-renamed-log to logs/%s: %s",
 980                                 newref, strerror(errno));
 981                         goto rollback;
 982                 }
 983         }
 984         logmoved = log;
 985
 986         lock = lock_ref_sha1_basic(newref, NULL, 0, NULL);
 987         if (!lock) {
 988                 error("unable to lock %s for update", newref);
 989                 goto rollback;
 990         }
 991
 992         lock->force_write = 1;
 993         hashcpy(lock->old_sha1, orig_sha1);
 994         if (write_ref_sha1(lock, orig_sha1, logmsg)) {
 995                 error("unable to write current sha1 into %s", newref);
 996                 goto rollback;
 997         }
 998
 999         return 0;
1000
1001  rollback:
1002         lock = lock_ref_sha1_basic(oldref, NULL, 0, NULL);
1003         if (!lock) {
1004                 error("unable to lock %s for rollback", oldref);
1005                 goto rollbacklog;
1006         }
1007
1008         lock->force_write = 1;
1009         flag = log_all_ref_updates;
1010         log_all_ref_updates = 0;
1011         if (write_ref_sha1(lock, orig_sha1, NULL))
1012                 error("unable to write current sha1 into %s", oldref);
1013         log_all_ref_updates = flag;
1014
1015  rollbacklog:
1016         if (logmoved && rename(git_path("logs/%s", newref), git_path("logs/%s", oldref)))
1017                 error("unable to restore logfile %s from %s: %s",
1018                         oldref, newref, strerror(errno));
1019         if (!logmoved && log &&
1020             rename(git_path("tmp-renamed-log"), git_path("logs/%s", oldref)))
1021                 error("unable to restore logfile %s from tmp-renamed-log: %s",
1022                         oldref, strerror(errno));
1023
1024         return 1;
1025 }
1026
1027 void unlock_ref(struct ref_lock *lock)
1028 {
1029         if (lock->lock_fd >= 0) {
1030                 close(lock->lock_fd);
1031                 /* Do not free lock->lk -- atexit() still looks at them */
1032                 if (lock->lk)
1033                         rollback_lock_file(lock->lk);
1034         }
1035         free(lock->ref_name);
1036         free(lock->orig_ref_name);
1037         free(lock);
1038 }
1039
1040 /*
1041  * copy the reflog message msg to buf, which has been allocated sufficiently
1042  * large, while cleaning up the whitespaces.  Especially, convert LF to space,
1043  * because reflog file is one line per entry.
1044  */
1045 static int copy_msg(char *buf, const char *msg)
1046 {
1047         char *cp = buf;
1048         char c;
1049         int wasspace = 1;
1050
1051         *cp++ = '\t';
1052         while ((c = *msg++)) {
1053                 if (wasspace && isspace(c))
1054                         continue;
1055                 wasspace = isspace(c);
1056                 if (wasspace)
1057                         c = ' ';
1058                 *cp++ = c;
1059         }
1060         while (buf < cp && isspace(cp[-1]))
1061                 cp--;
1062         *cp++ = '\n';
1063         return cp - buf;
1064 }
1065
1066 static int log_ref_write(const char *ref_name, const unsigned char *old_sha1,
1067                          const unsigned char *new_sha1, const char *msg)
1068 {
1069         int logfd, written, oflags = O_APPEND | O_WRONLY;
1070         unsigned maxlen, len;
1071         int msglen;
1072         char *log_file, *logrec;
1073         const char *committer;
1074
1075         if (log_all_ref_updates < 0)
1076                 log_all_ref_updates = !is_bare_repository();
1077
1078         log_file = git_path("logs/%s", ref_name);
1079
1080         if (log_all_ref_updates &&
1081             (!prefixcmp(ref_name, "refs/heads/") ||
1082              !prefixcmp(ref_name, "refs/remotes/") ||
1083              !strcmp(ref_name, "HEAD"))) {
1084                 if (safe_create_leading_directories(log_file) < 0)
1085                         return error("unable to create directory for %s",
1086                                      log_file);
1087                 oflags |= O_CREAT;
1088         }
1089
1090         logfd = open(log_file, oflags, 0666);
1091         if (logfd < 0) {
1092                 if (!(oflags & O_CREAT) && errno == ENOENT)
1093                         return 0;
1094
1095                 if ((oflags & O_CREAT) && errno == EISDIR) {
1096                         if (remove_empty_directories(log_file)) {
1097                                 return error("There are still logs under '%s'",
1098                                              log_file);
1099                         }
1100                         logfd = open(log_file, oflags, 0666);
1101                 }
1102
1103                 if (logfd < 0)
1104                         return error("Unable to append to %s: %s",
1105                                      log_file, strerror(errno));
1106         }
1107
1108         adjust_shared_perm(log_file);
1109
1110         msglen = msg ? strlen(msg) : 0;
1111         committer = git_committer_info(-1);
1112         maxlen = strlen(committer) + msglen + 100;
1113         logrec = xmalloc(maxlen);
1114         len = sprintf(logrec, "%s %s %s\n",
1115                       sha1_to_hex(old_sha1),
1116                       sha1_to_hex(new_sha1),
1117                       committer);
1118         if (msglen)
1119                 len += copy_msg(logrec + len - 1, msg) - 1;
1120         written = len <= maxlen ? write_in_full(logfd, logrec, len) : -1;
1121         free(logrec);
1122         if (close(logfd) != 0 || written != len)
1123                 return error("Unable to append to %s", log_file);
1124         return 0;
1125 }
1126
1127 int write_ref_sha1(struct ref_lock *lock,
1128         const unsigned char *sha1, const char *logmsg)
1129 {
1130         static char term = '\n';
1131
1132         if (!lock)
1133                 return -1;
1134         if (!lock->force_write && !hashcmp(lock->old_sha1, sha1)) {
1135                 unlock_ref(lock);
1136                 return 0;
1137         }
1138         if (write_in_full(lock->lock_fd, sha1_to_hex(sha1), 40) != 40 ||
1139             write_in_full(lock->lock_fd, &term, 1) != 1
1140                 || close(lock->lock_fd) < 0) {
1141                 error("Couldn't write %s", lock->lk->filename);
1142                 unlock_ref(lock);
1143                 return -1;
1144         }
1145         invalidate_cached_refs();
1146         if (log_ref_write(lock->ref_name, lock->old_sha1, sha1, logmsg) < 0 ||
1147             (strcmp(lock->ref_name, lock->orig_ref_name) &&
1148              log_ref_write(lock->orig_ref_name, lock->old_sha1, sha1, logmsg) < 0)) {
1149                 unlock_ref(lock);
1150                 return -1;
1151         }
1152         if (strcmp(lock->orig_ref_name, "HEAD") != 0) {
1153                 /*
1154                  * Special hack: If a branch is updated directly and HEAD
1155                  * points to it (may happen on the remote side of a push
1156                  * for example) then logically the HEAD reflog should be
1157                  * updated too.
1158                  * A generic solution implies reverse symref information,
1159                  * but finding all symrefs pointing to the given branch
1160                  * would be rather costly for this rare event (the direct
1161                  * update of a branch) to be worth it.  So let's cheat and
1162                  * check with HEAD only which should cover 99% of all usage
1163                  * scenarios (even 100% of the default ones).
1164                  */
1165                 unsigned char head_sha1[20];
1166                 int head_flag;
1167                 const char *head_ref;
1168                 head_ref = resolve_ref("HEAD", head_sha1, 1, &head_flag);
1169                 if (head_ref && (head_flag & REF_ISSYMREF) &&
1170                     !strcmp(head_ref, lock->ref_name))
1171                         log_ref_write("HEAD", lock->old_sha1, sha1, logmsg);
1172         }
1173         if (commit_lock_file(lock->lk)) {
1174                 error("Couldn't set %s", lock->ref_name);
1175                 unlock_ref(lock);
1176                 return -1;
1177         }
1178         lock->lock_fd = -1;
1179         unlock_ref(lock);
1180         return 0;
1181 }
1182
1183 int create_symref(const char *ref_target, const char *refs_heads_master,
1184                   const char *logmsg)
1185 {
1186         const char *lockpath;
1187         char ref[1000];
1188         int fd, len, written;
1189         char *git_HEAD = xstrdup(git_path("%s", ref_target));
1190         unsigned char old_sha1[20], new_sha1[20];
1191
1192         if (logmsg && read_ref(ref_target, old_sha1))
1193                 hashclr(old_sha1);
1194
1195         if (safe_create_leading_directories(git_HEAD) < 0)
1196                 return error("unable to create directory for %s", git_HEAD);
1197
1198 #ifndef NO_SYMLINK_HEAD
1199         if (prefer_symlink_refs) {
1200                 unlink(git_HEAD);
1201                 if (!symlink(refs_heads_master, git_HEAD))
1202                         goto done;
1203                 fprintf(stderr, "no symlink - falling back to symbolic ref\n");
1204         }
1205 #endif
1206
1207         len = snprintf(ref, sizeof(ref), "ref: %s\n", refs_heads_master);
1208         if (sizeof(ref) <= len) {
1209                 error("refname too long: %s", refs_heads_master);
1210                 goto error_free_return;
1211         }
1212         lockpath = mkpath("%s.lock", git_HEAD);
1213         fd = open(lockpath, O_CREAT | O_EXCL | O_WRONLY, 0666);
1214         if (fd < 0) {
1215                 error("Unable to open %s for writing", lockpath);
1216                 goto error_free_return;
1217         }
1218         written = write_in_full(fd, ref, len);
1219         if (close(fd) != 0 || written != len) {
1220                 error("Unable to write to %s", lockpath);
1221                 goto error_unlink_return;
1222         }
1223         if (rename(lockpath, git_HEAD) < 0) {
1224                 error("Unable to create %s", git_HEAD);
1225                 goto error_unlink_return;
1226         }
1227         if (adjust_shared_perm(git_HEAD)) {
1228                 error("Unable to fix permissions on %s", lockpath);
1229         error_unlink_return:
1230                 unlink(lockpath);
1231         error_free_return:
1232                 free(git_HEAD);
1233                 return -1;
1234         }
1235
1236 #ifndef NO_SYMLINK_HEAD
1237         done:
1238 #endif
1239         if (logmsg && !read_ref(refs_heads_master, new_sha1))
1240                 log_ref_write(ref_target, old_sha1, new_sha1, logmsg);
1241
1242         free(git_HEAD);
1243         return 0;
1244 }
1245
1246 static char *ref_msg(const char *line, const char *endp)
1247 {
1248         const char *ep;
1249         line += 82;
1250         ep = memchr(line, '\n', endp - line);
1251         if (!ep)
1252                 ep = endp;
1253         return xmemdupz(line, ep - line);
1254 }
1255
1256 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)
1257 {
1258         const char *logfile, *logdata, *logend, *rec, *lastgt, *lastrec;
1259         char *tz_c;
1260         int logfd, tz, reccnt = 0;
1261         struct stat st;
1262         unsigned long date;
1263         unsigned char logged_sha1[20];
1264         void *log_mapped;
1265         size_t mapsz;
1266
1267         logfile = git_path("logs/%s", ref);
1268         logfd = open(logfile, O_RDONLY, 0);
1269         if (logfd < 0)
1270                 die("Unable to read log %s: %s", logfile, strerror(errno));
1271         fstat(logfd, &st);
1272         if (!st.st_size)
1273                 die("Log %s is empty.", logfile);
1274         mapsz = xsize_t(st.st_size);
1275         log_mapped = xmmap(NULL, mapsz, PROT_READ, MAP_PRIVATE, logfd, 0);
1276         logdata = log_mapped;
1277         close(logfd);
1278
1279         lastrec = NULL;
1280         rec = logend = logdata + st.st_size;
1281         while (logdata < rec) {
1282                 reccnt++;
1283                 if (logdata < rec && *(rec-1) == '\n')
1284                         rec--;
1285                 lastgt = NULL;
1286                 while (logdata < rec && *(rec-1) != '\n') {
1287                         rec--;
1288                         if (*rec == '>')
1289                                 lastgt = rec;
1290                 }
1291                 if (!lastgt)
1292                         die("Log %s is corrupt.", logfile);
1293                 date = strtoul(lastgt + 1, &tz_c, 10);
1294                 if (date <= at_time || cnt == 0) {
1295                         tz = strtoul(tz_c, NULL, 10);
1296                         if (msg)
1297                                 *msg = ref_msg(rec, logend);
1298                         if (cutoff_time)
1299                                 *cutoff_time = date;
1300                         if (cutoff_tz)
1301                                 *cutoff_tz = tz;
1302                         if (cutoff_cnt)
1303                                 *cutoff_cnt = reccnt - 1;
1304                         if (lastrec) {
1305                                 if (get_sha1_hex(lastrec, logged_sha1))
1306                                         die("Log %s is corrupt.", logfile);
1307                                 if (get_sha1_hex(rec + 41, sha1))
1308                                         die("Log %s is corrupt.", logfile);
1309                                 if (hashcmp(logged_sha1, sha1)) {
1310                                         fprintf(stderr,
1311                                                 "warning: Log %s has gap after %s.\n",
1312                                                 logfile, show_date(date, tz, DATE_RFC2822));
1313                                 }
1314                         }
1315                         else if (date == at_time) {
1316                                 if (get_sha1_hex(rec + 41, sha1))
1317                                         die("Log %s is corrupt.", logfile);
1318                         }
1319                         else {
1320                                 if (get_sha1_hex(rec + 41, logged_sha1))
1321                                         die("Log %s is corrupt.", logfile);
1322                                 if (hashcmp(logged_sha1, sha1)) {
1323                                         fprintf(stderr,
1324                                                 "warning: Log %s unexpectedly ended on %s.\n",
1325                                                 logfile, show_date(date, tz, DATE_RFC2822));
1326                                 }
1327                         }
1328                         munmap(log_mapped, mapsz);
1329                         return 0;
1330                 }
1331                 lastrec = rec;
1332                 if (cnt > 0)
1333                         cnt--;
1334         }
1335
1336         rec = logdata;
1337         while (rec < logend && *rec != '>' && *rec != '\n')
1338                 rec++;
1339         if (rec == logend || *rec == '\n')
1340                 die("Log %s is corrupt.", logfile);
1341         date = strtoul(rec + 1, &tz_c, 10);
1342         tz = strtoul(tz_c, NULL, 10);
1343         if (get_sha1_hex(logdata, sha1))
1344                 die("Log %s is corrupt.", logfile);
1345         if (msg)
1346                 *msg = ref_msg(logdata, logend);
1347         munmap(log_mapped, mapsz);
1348
1349         if (cutoff_time)
1350                 *cutoff_time = date;
1351         if (cutoff_tz)
1352                 *cutoff_tz = tz;
1353         if (cutoff_cnt)
1354                 *cutoff_cnt = reccnt;
1355         return 1;
1356 }
1357
1358 int for_each_reflog_ent(const char *ref, each_reflog_ent_fn fn, void *cb_data)
1359 {
1360         const char *logfile;
1361         FILE *logfp;
1362         char buf[1024];
1363         int ret = 0;
1364
1365         logfile = git_path("logs/%s", ref);
1366         logfp = fopen(logfile, "r");
1367         if (!logfp)
1368                 return -1;
1369         while (fgets(buf, sizeof(buf), logfp)) {
1370                 unsigned char osha1[20], nsha1[20];
1371                 char *email_end, *message;
1372                 unsigned long timestamp;
1373                 int len, tz;
1374
1375                 /* old SP new SP name <email> SP time TAB msg LF */
1376                 len = strlen(buf);
1377                 if (len < 83 || buf[len-1] != '\n' ||
1378                     get_sha1_hex(buf, osha1) || buf[40] != ' ' ||
1379                     get_sha1_hex(buf + 41, nsha1) || buf[81] != ' ' ||
1380                     !(email_end = strchr(buf + 82, '>')) ||
1381                     email_end[1] != ' ' ||
1382                     !(timestamp = strtoul(email_end + 2, &message, 10)) ||
1383                     !message || message[0] != ' ' ||
1384                     (message[1] != '+' && message[1] != '-') ||
1385                     !isdigit(message[2]) || !isdigit(message[3]) ||
1386                     !isdigit(message[4]) || !isdigit(message[5]))
1387                         continue; /* corrupt? */
1388                 email_end[1] = '\0';
1389                 tz = strtol(message + 1, NULL, 10);
1390                 if (message[6] != '\t')
1391                         message += 6;
1392                 else
1393                         message += 7;
1394                 ret = fn(osha1, nsha1, buf+82, timestamp, tz, message, cb_data);
1395                 if (ret)
1396                         break;
1397         }
1398         fclose(logfp);
1399         return ret;
1400 }
1401
1402 static int do_for_each_reflog(const char *base, each_ref_fn fn, void *cb_data)
1403 {
1404         DIR *dir = opendir(git_path("logs/%s", base));
1405         int retval = 0;
1406
1407         if (dir) {
1408                 struct dirent *de;
1409                 int baselen = strlen(base);
1410                 char *log = xmalloc(baselen + 257);
1411
1412                 memcpy(log, base, baselen);
1413                 if (baselen && base[baselen-1] != '/')
1414                         log[baselen++] = '/';
1415
1416                 while ((de = readdir(dir)) != NULL) {
1417                         struct stat st;
1418                         int namelen;
1419
1420                         if (de->d_name[0] == '.')
1421                                 continue;
1422                         namelen = strlen(de->d_name);
1423                         if (namelen > 255)
1424                                 continue;
1425                         if (has_extension(de->d_name, ".lock"))
1426                                 continue;
1427                         memcpy(log + baselen, de->d_name, namelen+1);
1428                         if (stat(git_path("logs/%s", log), &st) < 0)
1429                                 continue;
1430                         if (S_ISDIR(st.st_mode)) {
1431                                 retval = do_for_each_reflog(log, fn, cb_data);
1432                         } else {
1433                                 unsigned char sha1[20];
1434                                 if (!resolve_ref(log, sha1, 0, NULL))
1435                                         retval = error("bad ref for %s", log);
1436                                 else
1437                                         retval = fn(log, sha1, 0, cb_data);
1438                         }
1439                         if (retval)
1440                                 break;
1441                 }
1442                 free(log);
1443                 closedir(dir);
1444         }
1445         else if (*base)
1446                 return errno;
1447         return retval;
1448 }
1449
1450 int for_each_reflog(each_ref_fn fn, void *cb_data)
1451 {
1452         return do_for_each_reflog("", fn, cb_data);
1453 }
1454
1455 int update_ref(const char *action, const char *refname,
1456                 const unsigned char *sha1, const unsigned char *oldval,
1457                 int flags, enum action_on_err onerr)
1458 {
1459         static struct ref_lock *lock;
1460         lock = lock_any_ref_for_update(refname, oldval, flags);
1461         if (!lock) {
1462                 const char *str = "Cannot lock the ref '%s'.";
1463                 switch (onerr) {
1464                 case MSG_ON_ERR: error(str, refname); break;
1465                 case DIE_ON_ERR: die(str, refname); break;
1466                 case QUIET_ON_ERR: break;
1467                 }
1468                 return 1;
1469         }
1470         if (write_ref_sha1(lock, sha1, action) < 0) {
1471                 const char *str = "Cannot update the ref '%s'.";
1472                 switch (onerr) {
1473                 case MSG_ON_ERR: error(str, refname); break;
1474                 case DIE_ON_ERR: die(str, refname); break;
1475                 case QUIET_ON_ERR: break;
1476                 }
1477                 return 1;
1478         }
1479         return 0;
1480 }