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 static struct ref_list *current_ref;
 161
 162 static void free_ref_list(struct ref_list *list)
 163 {
 164         struct ref_list *next;
 165         for ( ; list; list = next) {
 166                 next = list->next;
 167                 free(list);
 168         }
 169 }
 170
 171 static void invalidate_cached_refs(void)
 172 {
 173         struct cached_refs *ca = &cached_refs;
 174
 175         if (ca->did_loose && ca->loose)
 176                 free_ref_list(ca->loose);
 177         if (ca->did_packed && ca->packed)
 178                 free_ref_list(ca->packed);
 179         ca->loose = ca->packed = NULL;
 180         ca->did_loose = ca->did_packed = 0;
 181 }
 182
 183 static void read_packed_refs(FILE *f, struct cached_refs *cached_refs)
 184 {
 185         struct ref_list *list = NULL;
 186         struct ref_list *last = NULL;
 187         char refline[PATH_MAX];
 188         int flag = REF_ISPACKED;
 189
 190         while (fgets(refline, sizeof(refline), f)) {
 191                 unsigned char sha1[20];
 192                 const char *name;
 193                 static const char header[] = "# pack-refs with:";
 194
 195                 if (!strncmp(refline, header, sizeof(header)-1)) {
 196                         const char *traits = refline + sizeof(header) - 1;
 197                         if (strstr(traits, " peeled "))
 198                                 flag |= REF_KNOWS_PEELED;
 199                         /* perhaps other traits later as well */
 200                         continue;
 201                 }
 202
 203                 name = parse_ref_line(refline, sha1);
 204                 if (name) {
 205                         list = add_ref(name, sha1, flag, list, &last);
 206                         continue;
 207                 }
 208                 if (last &&
 209                     refline[0] == '^' &&
 210                     strlen(refline) == 42 &&
 211                     refline[41] == '\n' &&
 212                     !get_sha1_hex(refline + 1, sha1))
 213                         hashcpy(last->peeled, sha1);
 214         }
 215         cached_refs->packed = sort_ref_list(list);
 216 }
 217
 218 static struct ref_list *get_packed_refs(void)
 219 {
 220         if (!cached_refs.did_packed) {
 221                 FILE *f = fopen(git_path("packed-refs"), "r");
 222                 cached_refs.packed = NULL;
 223                 if (f) {
 224                         read_packed_refs(f, &cached_refs);
 225                         fclose(f);
 226                 }
 227                 cached_refs.did_packed = 1;
 228         }
 229         return cached_refs.packed;
 230 }
 231
 232 static struct ref_list *get_ref_dir(const char *base, struct ref_list *list)
 233 {
 234         DIR *dir = opendir(git_path("%s", base));
 235
 236         if (dir) {
 237                 struct dirent *de;
 238                 int baselen = strlen(base);
 239                 char *ref = xmalloc(baselen + 257);
 240
 241                 memcpy(ref, base, baselen);
 242                 if (baselen && base[baselen-1] != '/')
 243                         ref[baselen++] = '/';
 244
 245                 while ((de = readdir(dir)) != NULL) {
 246                         unsigned char sha1[20];
 247                         struct stat st;
 248                         int flag;
 249                         int namelen;
 250
 251                         if (de->d_name[0] == '.')
 252                                 continue;
 253                         namelen = strlen(de->d_name);
 254                         if (namelen > 255)
 255                                 continue;
 256                         if (has_extension(de->d_name, ".lock"))
 257                                 continue;
 258                         memcpy(ref + baselen, de->d_name, namelen+1);
 259                         if (stat(git_path("%s", ref), &st) < 0)
 260                                 continue;
 261                         if (S_ISDIR(st.st_mode)) {
 262                                 list = get_ref_dir(ref, list);
 263                                 continue;
 264                         }
 265                         if (!resolve_ref(ref, sha1, 1, &flag)) {
 266                                 error("%s points nowhere!", ref);
 267                                 continue;
 268                         }
 269                         list = add_ref(ref, sha1, flag, list, NULL);
 270                 }
 271                 free(ref);
 272                 closedir(dir);
 273         }
 274         return sort_ref_list(list);
 275 }
 276
 277 static struct ref_list *get_loose_refs(void)
 278 {
 279         if (!cached_refs.did_loose) {
 280                 cached_refs.loose = get_ref_dir("refs", NULL);
 281                 cached_refs.did_loose = 1;
 282         }
 283         return cached_refs.loose;
 284 }
 285
 286 /* We allow "recursive" symbolic refs. Only within reason, though */
 287 #define MAXDEPTH 5
 288 #define MAXREFLEN (1024)
 289
 290 static int resolve_gitlink_packed_ref(char *name, int pathlen, const char *refname, unsigned char *result)
 291 {
 292         FILE *f;
 293         struct cached_refs refs;
 294         struct ref_list *ref;
 295         int retval;
 296
 297         strcpy(name + pathlen, "packed-refs");
 298         f = fopen(name, "r");
 299         if (!f)
 300                 return -1;
 301         read_packed_refs(f, &refs);
 302         fclose(f);
 303         ref = refs.packed;
 304         retval = -1;
 305         while (ref) {
 306                 if (!strcmp(ref->name, refname)) {
 307                         retval = 0;
 308                         memcpy(result, ref->sha1, 20);
 309                         break;
 310                 }
 311                 ref = ref->next;
 312         }
 313         free_ref_list(refs.packed);
 314         return retval;
 315 }
 316
 317 static int resolve_gitlink_ref_recursive(char *name, int pathlen, const char *refname, unsigned char *result, int recursion)
 318 {
 319         int fd, len = strlen(refname);
 320         char buffer[128], *p;
 321
 322         if (recursion > MAXDEPTH || len > MAXREFLEN)
 323                 return -1;
 324         memcpy(name + pathlen, refname, len+1);
 325         fd = open(name, O_RDONLY);
 326         if (fd < 0)
 327                 return resolve_gitlink_packed_ref(name, pathlen, refname, result);
 328
 329         len = read(fd, buffer, sizeof(buffer)-1);
 330         close(fd);
 331         if (len < 0)
 332                 return -1;
 333         while (len && isspace(buffer[len-1]))
 334                 len--;
 335         buffer[len] = 0;
 336
 337         /* Was it a detached head or an old-fashioned symlink? */
 338         if (!get_sha1_hex(buffer, result))
 339                 return 0;
 340
 341         /* Symref? */
 342         if (strncmp(buffer, "ref:", 4))
 343                 return -1;
 344         p = buffer + 4;
 345         while (isspace(*p))
 346                 p++;
 347
 348         return resolve_gitlink_ref_recursive(name, pathlen, p, result, recursion+1);
 349 }
 350
 351 int resolve_gitlink_ref(const char *path, const char *refname, unsigned char *result)
 352 {
 353         int len = strlen(path), retval;
 354         char *gitdir;
 355
 356         while (len && path[len-1] == '/')
 357                 len--;
 358         if (!len)
 359                 return -1;
 360         gitdir = xmalloc(len + MAXREFLEN + 8);
 361         memcpy(gitdir, path, len);
 362         memcpy(gitdir + len, "/.git/", 7);
 363
 364         retval = resolve_gitlink_ref_recursive(gitdir, len+6, refname, result, 0);
 365         free(gitdir);
 366         return retval;
 367 }
 368
 369 const char *resolve_ref(const char *ref, unsigned char *sha1, int reading, int *flag)
 370 {
 371         int depth = MAXDEPTH;
 372         ssize_t len;
 373         char buffer[256];
 374         static char ref_buffer[256];
 375
 376         if (flag)
 377                 *flag = 0;
 378
 379         for (;;) {
 380                 const char *path = git_path("%s", ref);
 381                 struct stat st;
 382                 char *buf;
 383                 int fd;
 384
 385                 if (--depth < 0)
 386                         return NULL;
 387
 388                 /* Special case: non-existing file.
 389                  * Not having the refs/heads/new-branch is OK
 390                  * if we are writing into it, so is .git/HEAD
 391                  * that points at refs/heads/master still to be
 392                  * born.  It is NOT OK if we are resolving for
 393                  * reading.
 394                  */
 395                 if (lstat(path, &st) < 0) {
 396                         struct ref_list *list = get_packed_refs();
 397                         while (list) {
 398                                 if (!strcmp(ref, list->name)) {
 399                                         hashcpy(sha1, list->sha1);
 400                                         if (flag)
 401                                                 *flag |= REF_ISPACKED;
 402                                         return ref;
 403                                 }
 404                                 list = list->next;
 405                         }
 406                         if (reading || errno != ENOENT)
 407                                 return NULL;
 408                         hashclr(sha1);
 409                         return ref;
 410                 }
 411
 412                 /* Follow "normalized" - ie "refs/.." symlinks by hand */
 413                 if (S_ISLNK(st.st_mode)) {
 414                         len = readlink(path, buffer, sizeof(buffer)-1);
 415                         if (len >= 5 && !memcmp("refs/", buffer, 5)) {
 416                                 buffer[len] = 0;
 417                                 strcpy(ref_buffer, buffer);
 418                                 ref = ref_buffer;
 419                                 if (flag)
 420                                         *flag |= REF_ISSYMREF;
 421                                 continue;
 422                         }
 423                 }
 424
 425                 /* Is it a directory? */
 426                 if (S_ISDIR(st.st_mode)) {
 427                         errno = EISDIR;
 428                         return NULL;
 429                 }
 430
 431                 /*
 432                  * Anything else, just open it and try to use it as
 433                  * a ref
 434                  */
 435                 fd = open(path, O_RDONLY);
 436                 if (fd < 0)
 437                         return NULL;
 438                 len = read_in_full(fd, buffer, sizeof(buffer)-1);
 439                 close(fd);
 440
 441                 /*
 442                  * Is it a symbolic ref?
 443                  */
 444                 if (len < 4 || memcmp("ref:", buffer, 4))
 445                         break;
 446                 buf = buffer + 4;
 447                 len -= 4;
 448                 while (len && isspace(*buf))
 449                         buf++, len--;
 450                 while (len && isspace(buf[len-1]))
 451                         len--;
 452                 buf[len] = 0;
 453                 memcpy(ref_buffer, buf, len + 1);
 454                 ref = ref_buffer;
 455                 if (flag)
 456                         *flag |= REF_ISSYMREF;
 457         }
 458         if (len < 40 || get_sha1_hex(buffer, sha1))
 459                 return NULL;
 460         return ref;
 461 }
 462
 463 int read_ref(const char *ref, unsigned char *sha1)
 464 {
 465         if (resolve_ref(ref, sha1, 1, NULL))
 466                 return 0;
 467         return -1;
 468 }
 469
 470 static int do_one_ref(const char *base, each_ref_fn fn, int trim,
 471                       void *cb_data, struct ref_list *entry)
 472 {
 473         if (strncmp(base, entry->name, trim))
 474                 return 0;
 475         if (is_null_sha1(entry->sha1))
 476                 return 0;
 477         if (!has_sha1_file(entry->sha1)) {
 478                 error("%s does not point to a valid object!", entry->name);
 479                 return 0;
 480         }
 481         current_ref = entry;
 482         return fn(entry->name + trim, entry->sha1, entry->flag, cb_data);
 483 }
 484
 485 int peel_ref(const char *ref, unsigned char *sha1)
 486 {
 487         int flag;
 488         unsigned char base[20];
 489         struct object *o;
 490
 491         if (current_ref && (current_ref->name == ref
 492                 || !strcmp(current_ref->name, ref))) {
 493                 if (current_ref->flag & REF_KNOWS_PEELED) {
 494                         hashcpy(sha1, current_ref->peeled);
 495                         return 0;
 496                 }
 497                 hashcpy(base, current_ref->sha1);
 498                 goto fallback;
 499         }
 500
 501         if (!resolve_ref(ref, base, 1, &flag))
 502                 return -1;
 503
 504         if ((flag & REF_ISPACKED)) {
 505                 struct ref_list *list = get_packed_refs();
 506
 507                 while (list) {
 508                         if (!strcmp(list->name, ref)) {
 509                                 if (list->flag & REF_KNOWS_PEELED) {
 510                                         hashcpy(sha1, list->peeled);
 511                                         return 0;
 512                                 }
 513                                 /* older pack-refs did not leave peeled ones */
 514                                 break;
 515                         }
 516                         list = list->next;
 517                 }
 518         }
 519
 520 fallback:
 521         o = parse_object(base);
 522         if (o && o->type == OBJ_TAG) {
 523                 o = deref_tag(o, ref, 0);
 524                 if (o) {
 525                         hashcpy(sha1, o->sha1);
 526                         return 0;
 527                 }
 528         }
 529         return -1;
 530 }
 531
 532 static int do_for_each_ref(const char *base, each_ref_fn fn, int trim,
 533                            void *cb_data)
 534 {
 535         int retval = 0;
 536         struct ref_list *packed = get_packed_refs();
 537         struct ref_list *loose = get_loose_refs();
 538
 539         while (packed && loose) {
 540                 struct ref_list *entry;
 541                 int cmp = strcmp(packed->name, loose->name);
 542                 if (!cmp) {
 543                         packed = packed->next;
 544                         continue;
 545                 }
 546                 if (cmp > 0) {
 547                         entry = loose;
 548                         loose = loose->next;
 549                 } else {
 550                         entry = packed;
 551                         packed = packed->next;
 552                 }
 553                 retval = do_one_ref(base, fn, trim, cb_data, entry);
 554                 if (retval)
 555                         goto end_each;
 556         }
 557
 558         for (packed = packed ? packed : loose; packed; packed = packed->next) {
 559                 retval = do_one_ref(base, fn, trim, cb_data, packed);
 560                 if (retval)
 561                         goto end_each;
 562         }
 563
 564 end_each:
 565         current_ref = NULL;
 566         return retval;
 567 }
 568
 569 int head_ref(each_ref_fn fn, void *cb_data)
 570 {
 571         unsigned char sha1[20];
 572         int flag;
 573
 574         if (resolve_ref("HEAD", sha1, 1, &flag))
 575                 return fn("HEAD", sha1, flag, cb_data);
 576         return 0;
 577 }
 578
 579 int for_each_ref(each_ref_fn fn, void *cb_data)
 580 {
 581         return do_for_each_ref("refs/", fn, 0, cb_data);
 582 }
 583
 584 int for_each_tag_ref(each_ref_fn fn, void *cb_data)
 585 {
 586         return do_for_each_ref("refs/tags/", fn, 10, cb_data);
 587 }
 588
 589 int for_each_branch_ref(each_ref_fn fn, void *cb_data)
 590 {
 591         return do_for_each_ref("refs/heads/", fn, 11, cb_data);
 592 }
 593
 594 int for_each_remote_ref(each_ref_fn fn, void *cb_data)
 595 {
 596         return do_for_each_ref("refs/remotes/", fn, 13, cb_data);
 597 }
 598
 599 /*
 600  * Make sure "ref" is something reasonable to have under ".git/refs/";
 601  * We do not like it if:
 602  *
 603  * - any path component of it begins with ".", or
 604  * - it has double dots "..", or
 605  * - it has ASCII control character, "~", "^", ":" or SP, anywhere, or
 606  * - it ends with a "/".
 607  */
 608
 609 static inline int bad_ref_char(int ch)
 610 {
 611         if (((unsigned) ch) <= ' ' ||
 612             ch == '~' || ch == '^' || ch == ':')
 613                 return 1;
 614         /* 2.13 Pattern Matching Notation */
 615         if (ch == '?' || ch == '[') /* Unsupported */
 616                 return 1;
 617         if (ch == '*') /* Supported at the end */
 618                 return 2;
 619         return 0;
 620 }
 621
 622 int check_ref_format(const char *ref)
 623 {
 624         int ch, level, bad_type;
 625         const char *cp = ref;
 626
 627         level = 0;
 628         while (1) {
 629                 while ((ch = *cp++) == '/')
 630                         ; /* tolerate duplicated slashes */
 631                 if (!ch)
 632                         /* should not end with slashes */
 633                         return CHECK_REF_FORMAT_ERROR;
 634
 635                 /* we are at the beginning of the path component */
 636                 if (ch == '.')
 637                         return CHECK_REF_FORMAT_ERROR;
 638                 bad_type = bad_ref_char(ch);
 639                 if (bad_type) {
 640                         return (bad_type == 2 && !*cp)
 641                                 ? CHECK_REF_FORMAT_WILDCARD
 642                                 : CHECK_REF_FORMAT_ERROR;
 643                 }
 644
 645                 /* scan the rest of the path component */
 646                 while ((ch = *cp++) != 0) {
 647                         bad_type = bad_ref_char(ch);
 648                         if (bad_type) {
 649                                 return (bad_type == 2 && !*cp)
 650                                         ? CHECK_REF_FORMAT_WILDCARD
 651                                         : CHECK_REF_FORMAT_ERROR;
 652                         }
 653                         if (ch == '/')
 654                                 break;
 655                         if (ch == '.' && *cp == '.')
 656                                 return CHECK_REF_FORMAT_ERROR;
 657                 }
 658                 level++;
 659                 if (!ch) {
 660                         if (level < 2)
 661                                 return CHECK_REF_FORMAT_ONELEVEL;
 662                         return CHECK_REF_FORMAT_OK;
 663                 }
 664         }
 665 }
 666
 667 const char *ref_rev_parse_rules[] = {
 668         "%.*s",
 669         "refs/%.*s",
 670         "refs/tags/%.*s",
 671         "refs/heads/%.*s",
 672         "refs/remotes/%.*s",
 673         "refs/remotes/%.*s/HEAD",
 674         NULL
 675 };
 676
 677 const char *ref_fetch_rules[] = {
 678         "%.*s",
 679         "refs/%.*s",
 680         "refs/heads/%.*s",
 681         NULL
 682 };
 683
 684 int refname_match(const char *abbrev_name, const char *full_name, const char **rules)
 685 {
 686         const char **p;
 687         const int abbrev_name_len = strlen(abbrev_name);
 688
 689         for (p = rules; *p; p++) {
 690                 if (!strcmp(full_name, mkpath(*p, abbrev_name_len, abbrev_name))) {
 691                         return 1;
 692                 }
 693         }
 694
 695         return 0;
 696 }
 697
 698 static struct ref_lock *verify_lock(struct ref_lock *lock,
 699         const unsigned char *old_sha1, int mustexist)
 700 {
 701         if (!resolve_ref(lock->ref_name, lock->old_sha1, mustexist, NULL)) {
 702                 error("Can't verify ref %s", lock->ref_name);
 703                 unlock_ref(lock);
 704                 return NULL;
 705         }
 706         if (hashcmp(lock->old_sha1, old_sha1)) {
 707                 error("Ref %s is at %s but expected %s", lock->ref_name,
 708                         sha1_to_hex(lock->old_sha1), sha1_to_hex(old_sha1));
 709                 unlock_ref(lock);
 710                 return NULL;
 711         }
 712         return lock;
 713 }
 714
 715 static int remove_empty_directories(const char *file)
 716 {
 717         /* we want to create a file but there is a directory there;
 718          * if that is an empty directory (or a directory that contains
 719          * only empty directories), remove them.
 720          */
 721         struct strbuf path;
 722         int result;
 723
 724         strbuf_init(&path, 20);
 725         strbuf_addstr(&path, file);
 726
 727         result = remove_dir_recursively(&path, 1);
 728
 729         strbuf_release(&path);
 730
 731         return result;
 732 }
 733
 734 static int is_refname_available(const char *ref, const char *oldref,
 735                                 struct ref_list *list, int quiet)
 736 {
 737         int namlen = strlen(ref); /* e.g. 'foo/bar' */
 738         while (list) {
 739                 /* list->name could be 'foo' or 'foo/bar/baz' */
 740                 if (!oldref || strcmp(oldref, list->name)) {
 741                         int len = strlen(list->name);
 742                         int cmplen = (namlen < len) ? namlen : len;
 743                         const char *lead = (namlen < len) ? list->name : ref;
 744                         if (!strncmp(ref, list->name, cmplen) &&
 745                             lead[cmplen] == '/') {
 746                                 if (!quiet)
 747                                         error("'%s' exists; cannot create '%s'",
 748                                               list->name, ref);
 749                                 return 0;
 750                         }
 751                 }
 752                 list = list->next;
 753         }
 754         return 1;
 755 }
 756
 757 static struct ref_lock *lock_ref_sha1_basic(const char *ref, const unsigned char *old_sha1, int flags, int *type_p)
 758 {
 759         char *ref_file;
 760         const char *orig_ref = ref;
 761         struct ref_lock *lock;
 762         struct stat st;
 763         int last_errno = 0;
 764         int type;
 765         int mustexist = (old_sha1 && !is_null_sha1(old_sha1));
 766
 767         lock = xcalloc(1, sizeof(struct ref_lock));
 768         lock->lock_fd = -1;
 769
 770         ref = resolve_ref(ref, lock->old_sha1, mustexist, &type);
 771         if (!ref && errno == EISDIR) {
 772                 /* we are trying to lock foo but we used to
 773                  * have foo/bar which now does not exist;
 774                  * it is normal for the empty directory 'foo'
 775                  * to remain.
 776                  */
 777                 ref_file = git_path("%s", orig_ref);
 778                 if (remove_empty_directories(ref_file)) {
 779                         last_errno = errno;
 780                         error("there are still refs under '%s'", orig_ref);
 781                         goto error_return;
 782                 }
 783                 ref = resolve_ref(orig_ref, lock->old_sha1, mustexist, &type);
 784         }
 785         if (type_p)
 786             *type_p = type;
 787         if (!ref) {
 788                 last_errno = errno;
 789                 error("unable to resolve reference %s: %s",
 790                         orig_ref, strerror(errno));
 791                 goto error_return;
 792         }
 793         /* When the ref did not exist and we are creating it,
 794          * make sure there is no existing ref that is packed
 795          * whose name begins with our refname, nor a ref whose
 796          * name is a proper prefix of our refname.
 797          */
 798         if (is_null_sha1(lock->old_sha1) &&
 799             !is_refname_available(ref, NULL, get_packed_refs(), 0))
 800                 goto error_return;
 801
 802         lock->lk = xcalloc(1, sizeof(struct lock_file));
 803
 804         if (flags & REF_NODEREF)
 805                 ref = orig_ref;
 806         lock->ref_name = xstrdup(ref);
 807         lock->orig_ref_name = xstrdup(orig_ref);
 808         ref_file = git_path("%s", ref);
 809         if (lstat(ref_file, &st) && errno == ENOENT)
 810                 lock->force_write = 1;
 811         if ((flags & REF_NODEREF) && (type & REF_ISSYMREF))
 812                 lock->force_write = 1;
 813
 814         if (safe_create_leading_directories(ref_file)) {
 815                 last_errno = errno;
 816                 error("unable to create directory for %s", ref_file);
 817                 goto error_return;
 818         }
 819         lock->lock_fd = hold_lock_file_for_update(lock->lk, ref_file, 1);
 820
 821         return old_sha1 ? verify_lock(lock, old_sha1, mustexist) : lock;
 822
 823  error_return:
 824         unlock_ref(lock);
 825         errno = last_errno;
 826         return NULL;
 827 }
 828
 829 struct ref_lock *lock_ref_sha1(const char *ref, const unsigned char *old_sha1)
 830 {
 831         char refpath[PATH_MAX];
 832         if (check_ref_format(ref))
 833                 return NULL;
 834         strcpy(refpath, mkpath("refs/%s", ref));
 835         return lock_ref_sha1_basic(refpath, old_sha1, 0, NULL);
 836 }
 837
 838 struct ref_lock *lock_any_ref_for_update(const char *ref, const unsigned char *old_sha1, int flags)
 839 {
 840         switch (check_ref_format(ref)) {
 841         default:
 842                 return NULL;
 843         case 0:
 844         case CHECK_REF_FORMAT_ONELEVEL:
 845                 return lock_ref_sha1_basic(ref, old_sha1, flags, NULL);
 846         }
 847 }
 848
 849 static struct lock_file packlock;
 850
 851 static int repack_without_ref(const char *refname)
 852 {
 853         struct ref_list *list, *packed_ref_list;
 854         int fd;
 855         int found = 0;
 856
 857         packed_ref_list = get_packed_refs();
 858         for (list = packed_ref_list; list; list = list->next) {
 859                 if (!strcmp(refname, list->name)) {
 860                         found = 1;
 861                         break;
 862                 }
 863         }
 864         if (!found)
 865                 return 0;
 866         fd = hold_lock_file_for_update(&packlock, git_path("packed-refs"), 0);
 867         if (fd < 0)
 868                 return error("cannot delete '%s' from packed refs", refname);
 869
 870         for (list = packed_ref_list; list; list = list->next) {
 871                 char line[PATH_MAX + 100];
 872                 int len;
 873
 874                 if (!strcmp(refname, list->name))
 875                         continue;
 876                 len = snprintf(line, sizeof(line), "%s %s\n",
 877                                sha1_to_hex(list->sha1), list->name);
 878                 /* this should not happen but just being defensive */
 879                 if (len > sizeof(line))
 880                         die("too long a refname '%s'", list->name);
 881                 write_or_die(fd, line, len);
 882         }
 883         return commit_lock_file(&packlock);
 884 }
 885
 886 int delete_ref(const char *refname, const unsigned char *sha1)
 887 {
 888         struct ref_lock *lock;
 889         int err, i, ret = 0, flag = 0;
 890
 891         lock = lock_ref_sha1_basic(refname, sha1, 0, &flag);
 892         if (!lock)
 893                 return 1;
 894         if (!(flag & REF_ISPACKED)) {
 895                 /* loose */
 896                 i = strlen(lock->lk->filename) - 5; /* .lock */
 897                 lock->lk->filename[i] = 0;
 898                 err = unlink(lock->lk->filename);
 899                 if (err) {
 900                         ret = 1;
 901                         error("unlink(%s) failed: %s",
 902                               lock->lk->filename, strerror(errno));
 903                 }
 904                 lock->lk->filename[i] = '.';
 905         }
 906         /* removing the loose one could have resurrected an earlier
 907          * packed one.  Also, if it was not loose we need to repack
 908          * without it.
 909          */
 910         ret |= repack_without_ref(refname);
 911
 912         err = unlink(git_path("logs/%s", lock->ref_name));
 913         if (err && errno != ENOENT)
 914                 fprintf(stderr, "warning: unlink(%s) failed: %s",
 915                         git_path("logs/%s", lock->ref_name), strerror(errno));
 916         invalidate_cached_refs();
 917         unlock_ref(lock);
 918         return ret;
 919 }
 920
 921 int rename_ref(const char *oldref, const char *newref, const char *logmsg)
 922 {
 923         static const char renamed_ref[] = "RENAMED-REF";
 924         unsigned char sha1[20], orig_sha1[20];
 925         int flag = 0, logmoved = 0;
 926         struct ref_lock *lock;
 927         struct stat loginfo;
 928         int log = !lstat(git_path("logs/%s", oldref), &loginfo);
 929
 930         if (S_ISLNK(loginfo.st_mode))
 931                 return error("reflog for %s is a symlink", oldref);
 932
 933         if (!resolve_ref(oldref, orig_sha1, 1, &flag))
 934                 return error("refname %s not found", oldref);
 935
 936         if (!is_refname_available(newref, oldref, get_packed_refs(), 0))
 937                 return 1;
 938
 939         if (!is_refname_available(newref, oldref, get_loose_refs(), 0))
 940                 return 1;
 941
 942         lock = lock_ref_sha1_basic(renamed_ref, NULL, 0, NULL);
 943         if (!lock)
 944                 return error("unable to lock %s", renamed_ref);
 945         lock->force_write = 1;
 946         if (write_ref_sha1(lock, orig_sha1, logmsg))
 947                 return error("unable to save current sha1 in %s", renamed_ref);
 948
 949         if (log && rename(git_path("logs/%s", oldref), git_path("tmp-renamed-log")))
 950                 return error("unable to move logfile logs/%s to tmp-renamed-log: %s",
 951                         oldref, strerror(errno));
 952
 953         if (delete_ref(oldref, orig_sha1)) {
 954                 error("unable to delete old %s", oldref);
 955                 goto rollback;
 956         }
 957
 958         if (resolve_ref(newref, sha1, 1, &flag) && delete_ref(newref, sha1)) {
 959                 if (errno==EISDIR) {
 960                         if (remove_empty_directories(git_path("%s", newref))) {
 961                                 error("Directory not empty: %s", newref);
 962                                 goto rollback;
 963                         }
 964                 } else {
 965                         error("unable to delete existing %s", newref);
 966                         goto rollback;
 967                 }
 968         }
 969
 970         if (log && safe_create_leading_directories(git_path("logs/%s", newref))) {
 971                 error("unable to create directory for %s", newref);
 972                 goto rollback;
 973         }
 974
 975  retry:
 976         if (log && rename(git_path("tmp-renamed-log"), git_path("logs/%s", newref))) {
 977                 if (errno==EISDIR || errno==ENOTDIR) {
 978                         /*
 979                          * rename(a, b) when b is an existing
 980                          * directory ought to result in ISDIR, but
 981                          * Solaris 5.8 gives ENOTDIR.  Sheesh.
 982                          */
 983                         if (remove_empty_directories(git_path("logs/%s", newref))) {
 984                                 error("Directory not empty: logs/%s", newref);
 985                                 goto rollback;
 986                         }
 987                         goto retry;
 988                 } else {
 989                         error("unable to move logfile tmp-renamed-log to logs/%s: %s",
 990                                 newref, strerror(errno));
 991                         goto rollback;
 992                 }
 993         }
 994         logmoved = log;
 995
 996         lock = lock_ref_sha1_basic(newref, NULL, 0, NULL);
 997         if (!lock) {
 998                 error("unable to lock %s for update", newref);
 999                 goto rollback;
1000         }
1001
1002         lock->force_write = 1;
1003         hashcpy(lock->old_sha1, orig_sha1);
1004         if (write_ref_sha1(lock, orig_sha1, logmsg)) {
1005                 error("unable to write current sha1 into %s", newref);
1006                 goto rollback;
1007         }
1008
1009         return 0;
1010
1011  rollback:
1012         lock = lock_ref_sha1_basic(oldref, NULL, 0, NULL);
1013         if (!lock) {
1014                 error("unable to lock %s for rollback", oldref);
1015                 goto rollbacklog;
1016         }
1017
1018         lock->force_write = 1;
1019         flag = log_all_ref_updates;
1020         log_all_ref_updates = 0;
1021         if (write_ref_sha1(lock, orig_sha1, NULL))
1022                 error("unable to write current sha1 into %s", oldref);
1023         log_all_ref_updates = flag;
1024
1025  rollbacklog:
1026         if (logmoved && rename(git_path("logs/%s", newref), git_path("logs/%s", oldref)))
1027                 error("unable to restore logfile %s from %s: %s",
1028                         oldref, newref, strerror(errno));
1029         if (!logmoved && log &&
1030             rename(git_path("tmp-renamed-log"), git_path("logs/%s", oldref)))
1031                 error("unable to restore logfile %s from tmp-renamed-log: %s",
1032                         oldref, strerror(errno));
1033
1034         return 1;
1035 }
1036
1037 int close_ref(struct ref_lock *lock)
1038 {
1039         if (close_lock_file(lock->lk))
1040                 return -1;
1041         lock->lock_fd = -1;
1042         return 0;
1043 }
1044
1045 int commit_ref(struct ref_lock *lock)
1046 {
1047         if (commit_lock_file(lock->lk))
1048                 return -1;
1049         lock->lock_fd = -1;
1050         return 0;
1051 }
1052
1053 void unlock_ref(struct ref_lock *lock)
1054 {
1055         /* Do not free lock->lk -- atexit() still looks at them */
1056         if (lock->lk)
1057                 rollback_lock_file(lock->lk);
1058         free(lock->ref_name);
1059         free(lock->orig_ref_name);
1060         free(lock);
1061 }
1062
1063 /*
1064  * copy the reflog message msg to buf, which has been allocated sufficiently
1065  * large, while cleaning up the whitespaces.  Especially, convert LF to space,
1066  * because reflog file is one line per entry.
1067  */
1068 static int copy_msg(char *buf, const char *msg)
1069 {
1070         char *cp = buf;
1071         char c;
1072         int wasspace = 1;
1073
1074         *cp++ = '\t';
1075         while ((c = *msg++)) {
1076                 if (wasspace && isspace(c))
1077                         continue;
1078                 wasspace = isspace(c);
1079                 if (wasspace)
1080                         c = ' ';
1081                 *cp++ = c;
1082         }
1083         while (buf < cp && isspace(cp[-1]))
1084                 cp--;
1085         *cp++ = '\n';
1086         return cp - buf;
1087 }
1088
1089 static int log_ref_write(const char *ref_name, const unsigned char *old_sha1,
1090                          const unsigned char *new_sha1, const char *msg)
1091 {
1092         int logfd, written, oflags = O_APPEND | O_WRONLY;
1093         unsigned maxlen, len;
1094         int msglen;
1095         char *log_file, *logrec;
1096         const char *committer;
1097
1098         if (log_all_ref_updates < 0)
1099                 log_all_ref_updates = !is_bare_repository();
1100
1101         log_file = git_path("logs/%s", ref_name);
1102
1103         if (log_all_ref_updates &&
1104             (!prefixcmp(ref_name, "refs/heads/") ||
1105              !prefixcmp(ref_name, "refs/remotes/") ||
1106              !strcmp(ref_name, "HEAD"))) {
1107                 if (safe_create_leading_directories(log_file) < 0)
1108                         return error("unable to create directory for %s",
1109                                      log_file);
1110                 oflags |= O_CREAT;
1111         }
1112
1113         logfd = open(log_file, oflags, 0666);
1114         if (logfd < 0) {
1115                 if (!(oflags & O_CREAT) && errno == ENOENT)
1116                         return 0;
1117
1118                 if ((oflags & O_CREAT) && errno == EISDIR) {
1119                         if (remove_empty_directories(log_file)) {
1120                                 return error("There are still logs under '%s'",
1121                                              log_file);
1122                         }
1123                         logfd = open(log_file, oflags, 0666);
1124                 }
1125
1126                 if (logfd < 0)
1127                         return error("Unable to append to %s: %s",
1128                                      log_file, strerror(errno));
1129         }
1130
1131         adjust_shared_perm(log_file);
1132
1133         msglen = msg ? strlen(msg) : 0;
1134         committer = git_committer_info(0);
1135         maxlen = strlen(committer) + msglen + 100;
1136         logrec = xmalloc(maxlen);
1137         len = sprintf(logrec, "%s %s %s\n",
1138                       sha1_to_hex(old_sha1),
1139                       sha1_to_hex(new_sha1),
1140                       committer);
1141         if (msglen)
1142                 len += copy_msg(logrec + len - 1, msg) - 1;
1143         written = len <= maxlen ? write_in_full(logfd, logrec, len) : -1;
1144         free(logrec);
1145         if (close(logfd) != 0 || written != len)
1146                 return error("Unable to append to %s", log_file);
1147         return 0;
1148 }
1149
1150 static int is_branch(const char *refname)
1151 {
1152         return !strcmp(refname, "HEAD") || !prefixcmp(refname, "refs/heads/");
1153 }
1154
1155 int write_ref_sha1(struct ref_lock *lock,
1156         const unsigned char *sha1, const char *logmsg)
1157 {
1158         static char term = '\n';
1159         struct object *o;
1160
1161         if (!lock)
1162                 return -1;
1163         if (!lock->force_write && !hashcmp(lock->old_sha1, sha1)) {
1164                 unlock_ref(lock);
1165                 return 0;
1166         }
1167         o = parse_object(sha1);
1168         if (!o) {
1169                 error("Trying to write ref %s with nonexistant object %s",
1170                         lock->ref_name, sha1_to_hex(sha1));
1171                 unlock_ref(lock);
1172                 return -1;
1173         }
1174         if (o->type != OBJ_COMMIT && is_branch(lock->ref_name)) {
1175                 error("Trying to write non-commit object %s to branch %s",
1176                         sha1_to_hex(sha1), lock->ref_name);
1177                 unlock_ref(lock);
1178                 return -1;
1179         }
1180         if (write_in_full(lock->lock_fd, sha1_to_hex(sha1), 40) != 40 ||
1181             write_in_full(lock->lock_fd, &term, 1) != 1
1182                 || close_ref(lock) < 0) {
1183                 error("Couldn't write %s", lock->lk->filename);
1184                 unlock_ref(lock);
1185                 return -1;
1186         }
1187         invalidate_cached_refs();
1188         if (log_ref_write(lock->ref_name, lock->old_sha1, sha1, logmsg) < 0 ||
1189             (strcmp(lock->ref_name, lock->orig_ref_name) &&
1190              log_ref_write(lock->orig_ref_name, lock->old_sha1, sha1, logmsg) < 0)) {
1191                 unlock_ref(lock);
1192                 return -1;
1193         }
1194         if (strcmp(lock->orig_ref_name, "HEAD") != 0) {
1195                 /*
1196                  * Special hack: If a branch is updated directly and HEAD
1197                  * points to it (may happen on the remote side of a push
1198                  * for example) then logically the HEAD reflog should be
1199                  * updated too.
1200                  * A generic solution implies reverse symref information,
1201                  * but finding all symrefs pointing to the given branch
1202                  * would be rather costly for this rare event (the direct
1203                  * update of a branch) to be worth it.  So let's cheat and
1204                  * check with HEAD only which should cover 99% of all usage
1205                  * scenarios (even 100% of the default ones).
1206                  */
1207                 unsigned char head_sha1[20];
1208                 int head_flag;
1209                 const char *head_ref;
1210                 head_ref = resolve_ref("HEAD", head_sha1, 1, &head_flag);
1211                 if (head_ref && (head_flag & REF_ISSYMREF) &&
1212                     !strcmp(head_ref, lock->ref_name))
1213                         log_ref_write("HEAD", lock->old_sha1, sha1, logmsg);
1214         }
1215         if (commit_ref(lock)) {
1216                 error("Couldn't set %s", lock->ref_name);
1217                 unlock_ref(lock);
1218                 return -1;
1219         }
1220         unlock_ref(lock);
1221         return 0;
1222 }
1223
1224 int create_symref(const char *ref_target, const char *refs_heads_master,
1225                   const char *logmsg)
1226 {
1227         const char *lockpath;
1228         char ref[1000];
1229         int fd, len, written;
1230         char *git_HEAD = xstrdup(git_path("%s", ref_target));
1231         unsigned char old_sha1[20], new_sha1[20];
1232
1233         if (logmsg && read_ref(ref_target, old_sha1))
1234                 hashclr(old_sha1);
1235
1236         if (safe_create_leading_directories(git_HEAD) < 0)
1237                 return error("unable to create directory for %s", git_HEAD);
1238
1239 #ifndef NO_SYMLINK_HEAD
1240         if (prefer_symlink_refs) {
1241                 unlink(git_HEAD);
1242                 if (!symlink(refs_heads_master, git_HEAD))
1243                         goto done;
1244                 fprintf(stderr, "no symlink - falling back to symbolic ref\n");
1245         }
1246 #endif
1247
1248         len = snprintf(ref, sizeof(ref), "ref: %s\n", refs_heads_master);
1249         if (sizeof(ref) <= len) {
1250                 error("refname too long: %s", refs_heads_master);
1251                 goto error_free_return;
1252         }
1253         lockpath = mkpath("%s.lock", git_HEAD);
1254         fd = open(lockpath, O_CREAT | O_EXCL | O_WRONLY, 0666);
1255         if (fd < 0) {
1256                 error("Unable to open %s for writing", lockpath);
1257                 goto error_free_return;
1258         }
1259         written = write_in_full(fd, ref, len);
1260         if (close(fd) != 0 || written != len) {
1261                 error("Unable to write to %s", lockpath);
1262                 goto error_unlink_return;
1263         }
1264         if (rename(lockpath, git_HEAD) < 0) {
1265                 error("Unable to create %s", git_HEAD);
1266                 goto error_unlink_return;
1267         }
1268         if (adjust_shared_perm(git_HEAD)) {
1269                 error("Unable to fix permissions on %s", lockpath);
1270         error_unlink_return:
1271                 unlink(lockpath);
1272         error_free_return:
1273                 free(git_HEAD);
1274                 return -1;
1275         }
1276
1277 #ifndef NO_SYMLINK_HEAD
1278         done:
1279 #endif
1280         if (logmsg && !read_ref(refs_heads_master, new_sha1))
1281                 log_ref_write(ref_target, old_sha1, new_sha1, logmsg);
1282
1283         free(git_HEAD);
1284         return 0;
1285 }
1286
1287 static char *ref_msg(const char *line, const char *endp)
1288 {
1289         const char *ep;
1290         line += 82;
1291         ep = memchr(line, '\n', endp - line);
1292         if (!ep)
1293                 ep = endp;
1294         return xmemdupz(line, ep - line);
1295 }
1296
1297 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)
1298 {
1299         const char *logfile, *logdata, *logend, *rec, *lastgt, *lastrec;
1300         char *tz_c;
1301         int logfd, tz, reccnt = 0;
1302         struct stat st;
1303         unsigned long date;
1304         unsigned char logged_sha1[20];
1305         void *log_mapped;
1306         size_t mapsz;
1307
1308         logfile = git_path("logs/%s", ref);
1309         logfd = open(logfile, O_RDONLY, 0);
1310         if (logfd < 0)
1311                 die("Unable to read log %s: %s", logfile, strerror(errno));
1312         fstat(logfd, &st);
1313         if (!st.st_size)
1314                 die("Log %s is empty.", logfile);
1315         mapsz = xsize_t(st.st_size);
1316         log_mapped = xmmap(NULL, mapsz, PROT_READ, MAP_PRIVATE, logfd, 0);
1317         logdata = log_mapped;
1318         close(logfd);
1319
1320         lastrec = NULL;
1321         rec = logend = logdata + st.st_size;
1322         while (logdata < rec) {
1323                 reccnt++;
1324                 if (logdata < rec && *(rec-1) == '\n')
1325                         rec--;
1326                 lastgt = NULL;
1327                 while (logdata < rec && *(rec-1) != '\n') {
1328                         rec--;
1329                         if (*rec == '>')
1330                                 lastgt = rec;
1331                 }
1332                 if (!lastgt)
1333                         die("Log %s is corrupt.", logfile);
1334                 date = strtoul(lastgt + 1, &tz_c, 10);
1335                 if (date <= at_time || cnt == 0) {
1336                         tz = strtoul(tz_c, NULL, 10);
1337                         if (msg)
1338                                 *msg = ref_msg(rec, logend);
1339                         if (cutoff_time)
1340                                 *cutoff_time = date;
1341                         if (cutoff_tz)
1342                                 *cutoff_tz = tz;
1343                         if (cutoff_cnt)
1344                                 *cutoff_cnt = reccnt - 1;
1345                         if (lastrec) {
1346                                 if (get_sha1_hex(lastrec, logged_sha1))
1347                                         die("Log %s is corrupt.", logfile);
1348                                 if (get_sha1_hex(rec + 41, sha1))
1349                                         die("Log %s is corrupt.", logfile);
1350                                 if (hashcmp(logged_sha1, sha1)) {
1351                                         fprintf(stderr,
1352                                                 "warning: Log %s has gap after %s.\n",
1353                                                 logfile, show_date(date, tz, DATE_RFC2822));
1354                                 }
1355                         }
1356                         else if (date == at_time) {
1357                                 if (get_sha1_hex(rec + 41, sha1))
1358                                         die("Log %s is corrupt.", logfile);
1359                         }
1360                         else {
1361                                 if (get_sha1_hex(rec + 41, logged_sha1))
1362                                         die("Log %s is corrupt.", logfile);
1363                                 if (hashcmp(logged_sha1, sha1)) {
1364                                         fprintf(stderr,
1365                                                 "warning: Log %s unexpectedly ended on %s.\n",
1366                                                 logfile, show_date(date, tz, DATE_RFC2822));
1367                                 }
1368                         }
1369                         munmap(log_mapped, mapsz);
1370                         return 0;
1371                 }
1372                 lastrec = rec;
1373                 if (cnt > 0)
1374                         cnt--;
1375         }
1376
1377         rec = logdata;
1378         while (rec < logend && *rec != '>' && *rec != '\n')
1379                 rec++;
1380         if (rec == logend || *rec == '\n')
1381                 die("Log %s is corrupt.", logfile);
1382         date = strtoul(rec + 1, &tz_c, 10);
1383         tz = strtoul(tz_c, NULL, 10);
1384         if (get_sha1_hex(logdata, sha1))
1385                 die("Log %s is corrupt.", logfile);
1386         if (msg)
1387                 *msg = ref_msg(logdata, logend);
1388         munmap(log_mapped, mapsz);
1389
1390         if (cutoff_time)
1391                 *cutoff_time = date;
1392         if (cutoff_tz)
1393                 *cutoff_tz = tz;
1394         if (cutoff_cnt)
1395                 *cutoff_cnt = reccnt;
1396         return 1;
1397 }
1398
1399 int for_each_reflog_ent(const char *ref, each_reflog_ent_fn fn, void *cb_data)
1400 {
1401         const char *logfile;
1402         FILE *logfp;
1403         char buf[1024];
1404         int ret = 0;
1405
1406         logfile = git_path("logs/%s", ref);
1407         logfp = fopen(logfile, "r");
1408         if (!logfp)
1409                 return -1;
1410         while (fgets(buf, sizeof(buf), logfp)) {
1411                 unsigned char osha1[20], nsha1[20];
1412                 char *email_end, *message;
1413                 unsigned long timestamp;
1414                 int len, tz;
1415
1416                 /* old SP new SP name <email> SP time TAB msg LF */
1417                 len = strlen(buf);
1418                 if (len < 83 || buf[len-1] != '\n' ||
1419                     get_sha1_hex(buf, osha1) || buf[40] != ' ' ||
1420                     get_sha1_hex(buf + 41, nsha1) || buf[81] != ' ' ||
1421                     !(email_end = strchr(buf + 82, '>')) ||
1422                     email_end[1] != ' ' ||
1423                     !(timestamp = strtoul(email_end + 2, &message, 10)) ||
1424                     !message || message[0] != ' ' ||
1425                     (message[1] != '+' && message[1] != '-') ||
1426                     !isdigit(message[2]) || !isdigit(message[3]) ||
1427                     !isdigit(message[4]) || !isdigit(message[5]))
1428                         continue; /* corrupt? */
1429                 email_end[1] = '\0';
1430                 tz = strtol(message + 1, NULL, 10);
1431                 if (message[6] != '\t')
1432                         message += 6;
1433                 else
1434                         message += 7;
1435                 ret = fn(osha1, nsha1, buf+82, timestamp, tz, message, cb_data);
1436                 if (ret)
1437                         break;
1438         }
1439         fclose(logfp);
1440         return ret;
1441 }
1442
1443 static int do_for_each_reflog(const char *base, each_ref_fn fn, void *cb_data)
1444 {
1445         DIR *dir = opendir(git_path("logs/%s", base));
1446         int retval = 0;
1447
1448         if (dir) {
1449                 struct dirent *de;
1450                 int baselen = strlen(base);
1451                 char *log = xmalloc(baselen + 257);
1452
1453                 memcpy(log, base, baselen);
1454                 if (baselen && base[baselen-1] != '/')
1455                         log[baselen++] = '/';
1456
1457                 while ((de = readdir(dir)) != NULL) {
1458                         struct stat st;
1459                         int namelen;
1460
1461                         if (de->d_name[0] == '.')
1462                                 continue;
1463                         namelen = strlen(de->d_name);
1464                         if (namelen > 255)
1465                                 continue;
1466                         if (has_extension(de->d_name, ".lock"))
1467                                 continue;
1468                         memcpy(log + baselen, de->d_name, namelen+1);
1469                         if (stat(git_path("logs/%s", log), &st) < 0)
1470                                 continue;
1471                         if (S_ISDIR(st.st_mode)) {
1472                                 retval = do_for_each_reflog(log, fn, cb_data);
1473                         } else {
1474                                 unsigned char sha1[20];
1475                                 if (!resolve_ref(log, sha1, 0, NULL))
1476                                         retval = error("bad ref for %s", log);
1477                                 else
1478                                         retval = fn(log, sha1, 0, cb_data);
1479                         }
1480                         if (retval)
1481                                 break;
1482                 }
1483                 free(log);
1484                 closedir(dir);
1485         }
1486         else if (*base)
1487                 return errno;
1488         return retval;
1489 }
1490
1491 int for_each_reflog(each_ref_fn fn, void *cb_data)
1492 {
1493         return do_for_each_reflog("", fn, cb_data);
1494 }
1495
1496 int update_ref(const char *action, const char *refname,
1497                 const unsigned char *sha1, const unsigned char *oldval,
1498                 int flags, enum action_on_err onerr)
1499 {
1500         static struct ref_lock *lock;
1501         lock = lock_any_ref_for_update(refname, oldval, flags);
1502         if (!lock) {
1503                 const char *str = "Cannot lock the ref '%s'.";
1504                 switch (onerr) {
1505                 case MSG_ON_ERR: error(str, refname); break;
1506                 case DIE_ON_ERR: die(str, refname); break;
1507                 case QUIET_ON_ERR: break;
1508                 }
1509                 return 1;
1510         }
1511         if (write_ref_sha1(lock, sha1, action) < 0) {
1512                 const char *str = "Cannot update the ref '%s'.";
1513                 switch (onerr) {
1514                 case MSG_ON_ERR: error(str, refname); break;
1515                 case DIE_ON_ERR: die(str, refname); break;
1516                 case QUIET_ON_ERR: break;
1517                 }
1518                 return 1;
1519         }
1520         return 0;
1521 }
1522
1523 struct ref *find_ref_by_name(struct ref *list, const char *name)
1524 {
1525         for ( ; list; list = list->next)
1526                 if (!strcmp(list->name, name))
1527                         return list;
1528         return NULL;
1529 }