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 struct ref_list *extra_refs;
 163
 164 static void free_ref_list(struct ref_list *list)
 165 {
 166         struct ref_list *next;
 167         for ( ; list; list = next) {
 168                 next = list->next;
 169                 free(list);
 170         }
 171 }
 172
 173 static void invalidate_cached_refs(void)
 174 {
 175         struct cached_refs *ca = &cached_refs;
 176
 177         if (ca->did_loose && ca->loose)
 178                 free_ref_list(ca->loose);
 179         if (ca->did_packed && ca->packed)
 180                 free_ref_list(ca->packed);
 181         ca->loose = ca->packed = NULL;
 182         ca->did_loose = ca->did_packed = 0;
 183 }
 184
 185 static void read_packed_refs(FILE *f, struct cached_refs *cached_refs)
 186 {
 187         struct ref_list *list = NULL;
 188         struct ref_list *last = NULL;
 189         char refline[PATH_MAX];
 190         int flag = REF_ISPACKED;
 191
 192         while (fgets(refline, sizeof(refline), f)) {
 193                 unsigned char sha1[20];
 194                 const char *name;
 195                 static const char header[] = "# pack-refs with:";
 196
 197                 if (!strncmp(refline, header, sizeof(header)-1)) {
 198                         const char *traits = refline + sizeof(header) - 1;
 199                         if (strstr(traits, " peeled "))
 200                                 flag |= REF_KNOWS_PEELED;
 201                         /* perhaps other traits later as well */
 202                         continue;
 203                 }
 204
 205                 name = parse_ref_line(refline, sha1);
 206                 if (name) {
 207                         list = add_ref(name, sha1, flag, list, &last);
 208                         continue;
 209                 }
 210                 if (last &&
 211                     refline[0] == '^' &&
 212                     strlen(refline) == 42 &&
 213                     refline[41] == '\n' &&
 214                     !get_sha1_hex(refline + 1, sha1))
 215                         hashcpy(last->peeled, sha1);
 216         }
 217         cached_refs->packed = sort_ref_list(list);
 218 }
 219
 220 void add_extra_ref(const char *name, const unsigned char *sha1, int flag)
 221 {
 222         extra_refs = add_ref(name, sha1, flag, extra_refs, NULL);
 223 }
 224
 225 void clear_extra_refs(void)
 226 {
 227         free_ref_list(extra_refs);
 228         extra_refs = NULL;
 229 }
 230
 231 static struct ref_list *get_packed_refs(void)
 232 {
 233         if (!cached_refs.did_packed) {
 234                 FILE *f = fopen(git_path("packed-refs"), "r");
 235                 cached_refs.packed = NULL;
 236                 if (f) {
 237                         read_packed_refs(f, &cached_refs);
 238                         fclose(f);
 239                 }
 240                 cached_refs.did_packed = 1;
 241         }
 242         return cached_refs.packed;
 243 }
 244
 245 static struct ref_list *get_ref_dir(const char *base, struct ref_list *list)
 246 {
 247         DIR *dir = opendir(git_path("%s", base));
 248
 249         if (dir) {
 250                 struct dirent *de;
 251                 int baselen = strlen(base);
 252                 char *ref = xmalloc(baselen + 257);
 253
 254                 memcpy(ref, base, baselen);
 255                 if (baselen && base[baselen-1] != '/')
 256                         ref[baselen++] = '/';
 257
 258                 while ((de = readdir(dir)) != NULL) {
 259                         unsigned char sha1[20];
 260                         struct stat st;
 261                         int flag;
 262                         int namelen;
 263
 264                         if (de->d_name[0] == '.')
 265                                 continue;
 266                         namelen = strlen(de->d_name);
 267                         if (namelen > 255)
 268                                 continue;
 269                         if (has_extension(de->d_name, ".lock"))
 270                                 continue;
 271                         memcpy(ref + baselen, de->d_name, namelen+1);
 272                         if (stat(git_path("%s", ref), &st) < 0)
 273                                 continue;
 274                         if (S_ISDIR(st.st_mode)) {
 275                                 list = get_ref_dir(ref, list);
 276                                 continue;
 277                         }
 278                         if (!resolve_ref(ref, sha1, 1, &flag)) {
 279                                 error("%s points nowhere!", ref);
 280                                 continue;
 281                         }
 282                         list = add_ref(ref, sha1, flag, list, NULL);
 283                 }
 284                 free(ref);
 285                 closedir(dir);
 286         }
 287         return sort_ref_list(list);
 288 }
 289
 290 static struct ref_list *get_loose_refs(void)
 291 {
 292         if (!cached_refs.did_loose) {
 293                 cached_refs.loose = get_ref_dir("refs", NULL);
 294                 cached_refs.did_loose = 1;
 295         }
 296         return cached_refs.loose;
 297 }
 298
 299 /* We allow "recursive" symbolic refs. Only within reason, though */
 300 #define MAXDEPTH 5
 301 #define MAXREFLEN (1024)
 302
 303 static int resolve_gitlink_packed_ref(char *name, int pathlen, const char *refname, unsigned char *result)
 304 {
 305         FILE *f;
 306         struct cached_refs refs;
 307         struct ref_list *ref;
 308         int retval;
 309
 310         strcpy(name + pathlen, "packed-refs");
 311         f = fopen(name, "r");
 312         if (!f)
 313                 return -1;
 314         read_packed_refs(f, &refs);
 315         fclose(f);
 316         ref = refs.packed;
 317         retval = -1;
 318         while (ref) {
 319                 if (!strcmp(ref->name, refname)) {
 320                         retval = 0;
 321                         memcpy(result, ref->sha1, 20);
 322                         break;
 323                 }
 324                 ref = ref->next;
 325         }
 326         free_ref_list(refs.packed);
 327         return retval;
 328 }
 329
 330 static int resolve_gitlink_ref_recursive(char *name, int pathlen, const char *refname, unsigned char *result, int recursion)
 331 {
 332         int fd, len = strlen(refname);
 333         char buffer[128], *p;
 334
 335         if (recursion > MAXDEPTH || len > MAXREFLEN)
 336                 return -1;
 337         memcpy(name + pathlen, refname, len+1);
 338         fd = open(name, O_RDONLY);
 339         if (fd < 0)
 340                 return resolve_gitlink_packed_ref(name, pathlen, refname, result);
 341
 342         len = read(fd, buffer, sizeof(buffer)-1);
 343         close(fd);
 344         if (len < 0)
 345                 return -1;
 346         while (len && isspace(buffer[len-1]))
 347                 len--;
 348         buffer[len] = 0;
 349
 350         /* Was it a detached head or an old-fashioned symlink? */
 351         if (!get_sha1_hex(buffer, result))
 352                 return 0;
 353
 354         /* Symref? */
 355         if (strncmp(buffer, "ref:", 4))
 356                 return -1;
 357         p = buffer + 4;
 358         while (isspace(*p))
 359                 p++;
 360
 361         return resolve_gitlink_ref_recursive(name, pathlen, p, result, recursion+1);
 362 }
 363
 364 int resolve_gitlink_ref(const char *path, const char *refname, unsigned char *result)
 365 {
 366         int len = strlen(path), retval;
 367         char *gitdir;
 368
 369         while (len && path[len-1] == '/')
 370                 len--;
 371         if (!len)
 372                 return -1;
 373         gitdir = xmalloc(len + MAXREFLEN + 8);
 374         memcpy(gitdir, path, len);
 375         memcpy(gitdir + len, "/.git/", 7);
 376
 377         retval = resolve_gitlink_ref_recursive(gitdir, len+6, refname, result, 0);
 378         free(gitdir);
 379         return retval;
 380 }
 381
 382 const char *resolve_ref(const char *ref, unsigned char *sha1, int reading, int *flag)
 383 {
 384         int depth = MAXDEPTH;
 385         ssize_t len;
 386         char buffer[256];
 387         static char ref_buffer[256];
 388
 389         if (flag)
 390                 *flag = 0;
 391
 392         for (;;) {
 393                 const char *path = git_path("%s", ref);
 394                 struct stat st;
 395                 char *buf;
 396                 int fd;
 397
 398                 if (--depth < 0)
 399                         return NULL;
 400
 401                 /* Special case: non-existing file.
 402                  * Not having the refs/heads/new-branch is OK
 403                  * if we are writing into it, so is .git/HEAD
 404                  * that points at refs/heads/master still to be
 405                  * born.  It is NOT OK if we are resolving for
 406                  * reading.
 407                  */
 408                 if (lstat(path, &st) < 0) {
 409                         struct ref_list *list = get_packed_refs();
 410                         while (list) {
 411                                 if (!strcmp(ref, list->name)) {
 412                                         hashcpy(sha1, list->sha1);
 413                                         if (flag)
 414                                                 *flag |= REF_ISPACKED;
 415                                         return ref;
 416                                 }
 417                                 list = list->next;
 418                         }
 419                         if (reading || errno != ENOENT)
 420                                 return NULL;
 421                         hashclr(sha1);
 422                         return ref;
 423                 }
 424
 425                 /* Follow "normalized" - ie "refs/.." symlinks by hand */
 426                 if (S_ISLNK(st.st_mode)) {
 427                         len = readlink(path, buffer, sizeof(buffer)-1);
 428                         if (len >= 5 && !memcmp("refs/", buffer, 5)) {
 429                                 buffer[len] = 0;
 430                                 strcpy(ref_buffer, buffer);
 431                                 ref = ref_buffer;
 432                                 if (flag)
 433                                         *flag |= REF_ISSYMREF;
 434                                 continue;
 435                         }
 436                 }
 437
 438                 /* Is it a directory? */
 439                 if (S_ISDIR(st.st_mode)) {
 440                         errno = EISDIR;
 441                         return NULL;
 442                 }
 443
 444                 /*
 445                  * Anything else, just open it and try to use it as
 446                  * a ref
 447                  */
 448                 fd = open(path, O_RDONLY);
 449                 if (fd < 0)
 450                         return NULL;
 451                 len = read_in_full(fd, buffer, sizeof(buffer)-1);
 452                 close(fd);
 453
 454                 /*
 455                  * Is it a symbolic ref?
 456                  */
 457                 if (len < 4 || memcmp("ref:", buffer, 4))
 458                         break;
 459                 buf = buffer + 4;
 460                 len -= 4;
 461                 while (len && isspace(*buf))
 462                         buf++, len--;
 463                 while (len && isspace(buf[len-1]))
 464                         len--;
 465                 buf[len] = 0;
 466                 memcpy(ref_buffer, buf, len + 1);
 467                 ref = ref_buffer;
 468                 if (flag)
 469                         *flag |= REF_ISSYMREF;
 470         }
 471         if (len < 40 || get_sha1_hex(buffer, sha1))
 472                 return NULL;
 473         return ref;
 474 }
 475
 476 int read_ref(const char *ref, unsigned char *sha1)
 477 {
 478         if (resolve_ref(ref, sha1, 1, NULL))
 479                 return 0;
 480         return -1;
 481 }
 482
 483 static int do_one_ref(const char *base, each_ref_fn fn, int trim,
 484                       void *cb_data, struct ref_list *entry)
 485 {
 486         if (strncmp(base, entry->name, trim))
 487                 return 0;
 488         if (is_null_sha1(entry->sha1))
 489                 return 0;
 490         if (!has_sha1_file(entry->sha1)) {
 491                 error("%s does not point to a valid object!", entry->name);
 492                 return 0;
 493         }
 494         current_ref = entry;
 495         return fn(entry->name + trim, entry->sha1, entry->flag, cb_data);
 496 }
 497
 498 int peel_ref(const char *ref, unsigned char *sha1)
 499 {
 500         int flag;
 501         unsigned char base[20];
 502         struct object *o;
 503
 504         if (current_ref && (current_ref->name == ref
 505                 || !strcmp(current_ref->name, ref))) {
 506                 if (current_ref->flag & REF_KNOWS_PEELED) {
 507                         hashcpy(sha1, current_ref->peeled);
 508                         return 0;
 509                 }
 510                 hashcpy(base, current_ref->sha1);
 511                 goto fallback;
 512         }
 513
 514         if (!resolve_ref(ref, base, 1, &flag))
 515                 return -1;
 516
 517         if ((flag & REF_ISPACKED)) {
 518                 struct ref_list *list = get_packed_refs();
 519
 520                 while (list) {
 521                         if (!strcmp(list->name, ref)) {
 522                                 if (list->flag & REF_KNOWS_PEELED) {
 523                                         hashcpy(sha1, list->peeled);
 524                                         return 0;
 525                                 }
 526                                 /* older pack-refs did not leave peeled ones */
 527                                 break;
 528                         }
 529                         list = list->next;
 530                 }
 531         }
 532
 533 fallback:
 534         o = parse_object(base);
 535         if (o && o->type == OBJ_TAG) {
 536                 o = deref_tag(o, ref, 0);
 537                 if (o) {
 538                         hashcpy(sha1, o->sha1);
 539                         return 0;
 540                 }
 541         }
 542         return -1;
 543 }
 544
 545 static int do_for_each_ref(const char *base, each_ref_fn fn, int trim,
 546                            void *cb_data)
 547 {
 548         int retval = 0;
 549         struct ref_list *packed = get_packed_refs();
 550         struct ref_list *loose = get_loose_refs();
 551
 552         struct ref_list *extra;
 553
 554         for (extra = extra_refs; extra; extra = extra->next)
 555                 retval = do_one_ref(base, fn, trim, cb_data, extra);
 556
 557         while (packed && loose) {
 558                 struct ref_list *entry;
 559                 int cmp = strcmp(packed->name, loose->name);
 560                 if (!cmp) {
 561                         packed = packed->next;
 562                         continue;
 563                 }
 564                 if (cmp > 0) {
 565                         entry = loose;
 566                         loose = loose->next;
 567                 } else {
 568                         entry = packed;
 569                         packed = packed->next;
 570                 }
 571                 retval = do_one_ref(base, fn, trim, cb_data, entry);
 572                 if (retval)
 573                         goto end_each;
 574         }
 575
 576         for (packed = packed ? packed : loose; packed; packed = packed->next) {
 577                 retval = do_one_ref(base, fn, trim, cb_data, packed);
 578                 if (retval)
 579                         goto end_each;
 580         }
 581
 582 end_each:
 583         current_ref = NULL;
 584         return retval;
 585 }
 586
 587 int head_ref(each_ref_fn fn, void *cb_data)
 588 {
 589         unsigned char sha1[20];
 590         int flag;
 591
 592         if (resolve_ref("HEAD", sha1, 1, &flag))
 593                 return fn("HEAD", sha1, flag, cb_data);
 594         return 0;
 595 }
 596
 597 int for_each_ref(each_ref_fn fn, void *cb_data)
 598 {
 599         return do_for_each_ref("refs/", fn, 0, cb_data);
 600 }
 601
 602 int for_each_tag_ref(each_ref_fn fn, void *cb_data)
 603 {
 604         return do_for_each_ref("refs/tags/", fn, 10, cb_data);
 605 }
 606
 607 int for_each_branch_ref(each_ref_fn fn, void *cb_data)
 608 {
 609         return do_for_each_ref("refs/heads/", fn, 11, cb_data);
 610 }
 611
 612 int for_each_remote_ref(each_ref_fn fn, void *cb_data)
 613 {
 614         return do_for_each_ref("refs/remotes/", fn, 13, cb_data);
 615 }
 616
 617 /*
 618  * Make sure "ref" is something reasonable to have under ".git/refs/";
 619  * We do not like it if:
 620  *
 621  * - any path component of it begins with ".", or
 622  * - it has double dots "..", or
 623  * - it has ASCII control character, "~", "^", ":" or SP, anywhere, or
 624  * - it ends with a "/".
 625  */
 626
 627 static inline int bad_ref_char(int ch)
 628 {
 629         if (((unsigned) ch) <= ' ' ||
 630             ch == '~' || ch == '^' || ch == ':')
 631                 return 1;
 632         /* 2.13 Pattern Matching Notation */
 633         if (ch == '?' || ch == '[') /* Unsupported */
 634                 return 1;
 635         if (ch == '*') /* Supported at the end */
 636                 return 2;
 637         return 0;
 638 }
 639
 640 int check_ref_format(const char *ref)
 641 {
 642         int ch, level, bad_type;
 643         const char *cp = ref;
 644
 645         level = 0;
 646         while (1) {
 647                 while ((ch = *cp++) == '/')
 648                         ; /* tolerate duplicated slashes */
 649                 if (!ch)
 650                         /* should not end with slashes */
 651                         return CHECK_REF_FORMAT_ERROR;
 652
 653                 /* we are at the beginning of the path component */
 654                 if (ch == '.')
 655                         return CHECK_REF_FORMAT_ERROR;
 656                 bad_type = bad_ref_char(ch);
 657                 if (bad_type) {
 658                         return (bad_type == 2 && !*cp)
 659                                 ? CHECK_REF_FORMAT_WILDCARD
 660                                 : CHECK_REF_FORMAT_ERROR;
 661                 }
 662
 663                 /* scan the rest of the path component */
 664                 while ((ch = *cp++) != 0) {
 665                         bad_type = bad_ref_char(ch);
 666                         if (bad_type) {
 667                                 return (bad_type == 2 && !*cp)
 668                                         ? CHECK_REF_FORMAT_WILDCARD
 669                                         : CHECK_REF_FORMAT_ERROR;
 670                         }
 671                         if (ch == '/')
 672                                 break;
 673                         if (ch == '.' && *cp == '.')
 674                                 return CHECK_REF_FORMAT_ERROR;
 675                 }
 676                 level++;
 677                 if (!ch) {
 678                         if (level < 2)
 679                                 return CHECK_REF_FORMAT_ONELEVEL;
 680                         return CHECK_REF_FORMAT_OK;
 681                 }
 682         }
 683 }
 684
 685 const char *ref_rev_parse_rules[] = {
 686         "%.*s",
 687         "refs/%.*s",
 688         "refs/tags/%.*s",
 689         "refs/heads/%.*s",
 690         "refs/remotes/%.*s",
 691         "refs/remotes/%.*s/HEAD",
 692         NULL
 693 };
 694
 695 const char *ref_fetch_rules[] = {
 696         "%.*s",
 697         "refs/%.*s",
 698         "refs/heads/%.*s",
 699         NULL
 700 };
 701
 702 int refname_match(const char *abbrev_name, const char *full_name, const char **rules)
 703 {
 704         const char **p;
 705         const int abbrev_name_len = strlen(abbrev_name);
 706
 707         for (p = rules; *p; p++) {
 708                 if (!strcmp(full_name, mkpath(*p, abbrev_name_len, abbrev_name))) {
 709                         return 1;
 710                 }
 711         }
 712
 713         return 0;
 714 }
 715
 716 static struct ref_lock *verify_lock(struct ref_lock *lock,
 717         const unsigned char *old_sha1, int mustexist)
 718 {
 719         if (!resolve_ref(lock->ref_name, lock->old_sha1, mustexist, NULL)) {
 720                 error("Can't verify ref %s", lock->ref_name);
 721                 unlock_ref(lock);
 722                 return NULL;
 723         }
 724         if (hashcmp(lock->old_sha1, old_sha1)) {
 725                 error("Ref %s is at %s but expected %s", lock->ref_name,
 726                         sha1_to_hex(lock->old_sha1), sha1_to_hex(old_sha1));
 727                 unlock_ref(lock);
 728                 return NULL;
 729         }
 730         return lock;
 731 }
 732
 733 static int remove_empty_directories(const char *file)
 734 {
 735         /* we want to create a file but there is a directory there;
 736          * if that is an empty directory (or a directory that contains
 737          * only empty directories), remove them.
 738          */
 739         struct strbuf path;
 740         int result;
 741
 742         strbuf_init(&path, 20);
 743         strbuf_addstr(&path, file);
 744
 745         result = remove_dir_recursively(&path, 1);
 746
 747         strbuf_release(&path);
 748
 749         return result;
 750 }
 751
 752 static int is_refname_available(const char *ref, const char *oldref,
 753                                 struct ref_list *list, int quiet)
 754 {
 755         int namlen = strlen(ref); /* e.g. 'foo/bar' */
 756         while (list) {
 757                 /* list->name could be 'foo' or 'foo/bar/baz' */
 758                 if (!oldref || strcmp(oldref, list->name)) {
 759                         int len = strlen(list->name);
 760                         int cmplen = (namlen < len) ? namlen : len;
 761                         const char *lead = (namlen < len) ? list->name : ref;
 762                         if (!strncmp(ref, list->name, cmplen) &&
 763                             lead[cmplen] == '/') {
 764                                 if (!quiet)
 765                                         error("'%s' exists; cannot create '%s'",
 766                                               list->name, ref);
 767                                 return 0;
 768                         }
 769                 }
 770                 list = list->next;
 771         }
 772         return 1;
 773 }
 774
 775 static struct ref_lock *lock_ref_sha1_basic(const char *ref, const unsigned char *old_sha1, int flags, int *type_p)
 776 {
 777         char *ref_file;
 778         const char *orig_ref = ref;
 779         struct ref_lock *lock;
 780         struct stat st;
 781         int last_errno = 0;
 782         int type;
 783         int mustexist = (old_sha1 && !is_null_sha1(old_sha1));
 784
 785         lock = xcalloc(1, sizeof(struct ref_lock));
 786         lock->lock_fd = -1;
 787
 788         ref = resolve_ref(ref, lock->old_sha1, mustexist, &type);
 789         if (!ref && errno == EISDIR) {
 790                 /* we are trying to lock foo but we used to
 791                  * have foo/bar which now does not exist;
 792                  * it is normal for the empty directory 'foo'
 793                  * to remain.
 794                  */
 795                 ref_file = git_path("%s", orig_ref);
 796                 if (remove_empty_directories(ref_file)) {
 797                         last_errno = errno;
 798                         error("there are still refs under '%s'", orig_ref);
 799                         goto error_return;
 800                 }
 801                 ref = resolve_ref(orig_ref, lock->old_sha1, mustexist, &type);
 802         }
 803         if (type_p)
 804             *type_p = type;
 805         if (!ref) {
 806                 last_errno = errno;
 807                 error("unable to resolve reference %s: %s",
 808                         orig_ref, strerror(errno));
 809                 goto error_return;
 810         }
 811         /* When the ref did not exist and we are creating it,
 812          * make sure there is no existing ref that is packed
 813          * whose name begins with our refname, nor a ref whose
 814          * name is a proper prefix of our refname.
 815          */
 816         if (is_null_sha1(lock->old_sha1) &&
 817             !is_refname_available(ref, NULL, get_packed_refs(), 0))
 818                 goto error_return;
 819
 820         lock->lk = xcalloc(1, sizeof(struct lock_file));
 821
 822         if (flags & REF_NODEREF)
 823                 ref = orig_ref;
 824         lock->ref_name = xstrdup(ref);
 825         lock->orig_ref_name = xstrdup(orig_ref);
 826         ref_file = git_path("%s", ref);
 827         if (lstat(ref_file, &st) && errno == ENOENT)
 828                 lock->force_write = 1;
 829         if ((flags & REF_NODEREF) && (type & REF_ISSYMREF))
 830                 lock->force_write = 1;
 831
 832         if (safe_create_leading_directories(ref_file)) {
 833                 last_errno = errno;
 834                 error("unable to create directory for %s", ref_file);
 835                 goto error_return;
 836         }
 837         lock->lock_fd = hold_lock_file_for_update(lock->lk, ref_file, 1);
 838
 839         return old_sha1 ? verify_lock(lock, old_sha1, mustexist) : lock;
 840
 841  error_return:
 842         unlock_ref(lock);
 843         errno = last_errno;
 844         return NULL;
 845 }
 846
 847 struct ref_lock *lock_ref_sha1(const char *ref, const unsigned char *old_sha1)
 848 {
 849         char refpath[PATH_MAX];
 850         if (check_ref_format(ref))
 851                 return NULL;
 852         strcpy(refpath, mkpath("refs/%s", ref));
 853         return lock_ref_sha1_basic(refpath, old_sha1, 0, NULL);
 854 }
 855
 856 struct ref_lock *lock_any_ref_for_update(const char *ref, const unsigned char *old_sha1, int flags)
 857 {
 858         switch (check_ref_format(ref)) {
 859         default:
 860                 return NULL;
 861         case 0:
 862         case CHECK_REF_FORMAT_ONELEVEL:
 863                 return lock_ref_sha1_basic(ref, old_sha1, flags, NULL);
 864         }
 865 }
 866
 867 static struct lock_file packlock;
 868
 869 static int repack_without_ref(const char *refname)
 870 {
 871         struct ref_list *list, *packed_ref_list;
 872         int fd;
 873         int found = 0;
 874
 875         packed_ref_list = get_packed_refs();
 876         for (list = packed_ref_list; list; list = list->next) {
 877                 if (!strcmp(refname, list->name)) {
 878                         found = 1;
 879                         break;
 880                 }
 881         }
 882         if (!found)
 883                 return 0;
 884         fd = hold_lock_file_for_update(&packlock, git_path("packed-refs"), 0);
 885         if (fd < 0)
 886                 return error("cannot delete '%s' from packed refs", refname);
 887
 888         for (list = packed_ref_list; list; list = list->next) {
 889                 char line[PATH_MAX + 100];
 890                 int len;
 891
 892                 if (!strcmp(refname, list->name))
 893                         continue;
 894                 len = snprintf(line, sizeof(line), "%s %s\n",
 895                                sha1_to_hex(list->sha1), list->name);
 896                 /* this should not happen but just being defensive */
 897                 if (len > sizeof(line))
 898                         die("too long a refname '%s'", list->name);
 899                 write_or_die(fd, line, len);
 900         }
 901         return commit_lock_file(&packlock);
 902 }
 903
 904 int delete_ref(const char *refname, const unsigned char *sha1)
 905 {
 906         struct ref_lock *lock;
 907         int err, i, ret = 0, flag = 0;
 908
 909         lock = lock_ref_sha1_basic(refname, sha1, 0, &flag);
 910         if (!lock)
 911                 return 1;
 912         if (!(flag & REF_ISPACKED)) {
 913                 /* loose */
 914                 i = strlen(lock->lk->filename) - 5; /* .lock */
 915                 lock->lk->filename[i] = 0;
 916                 err = unlink(lock->lk->filename);
 917                 if (err) {
 918                         ret = 1;
 919                         error("unlink(%s) failed: %s",
 920                               lock->lk->filename, strerror(errno));
 921                 }
 922                 lock->lk->filename[i] = '.';
 923         }
 924         /* removing the loose one could have resurrected an earlier
 925          * packed one.  Also, if it was not loose we need to repack
 926          * without it.
 927          */
 928         ret |= repack_without_ref(refname);
 929
 930         err = unlink(git_path("logs/%s", lock->ref_name));
 931         if (err && errno != ENOENT)
 932                 fprintf(stderr, "warning: unlink(%s) failed: %s",
 933                         git_path("logs/%s", lock->ref_name), strerror(errno));
 934         invalidate_cached_refs();
 935         unlock_ref(lock);
 936         return ret;
 937 }
 938
 939 int rename_ref(const char *oldref, const char *newref, const char *logmsg)
 940 {
 941         static const char renamed_ref[] = "RENAMED-REF";
 942         unsigned char sha1[20], orig_sha1[20];
 943         int flag = 0, logmoved = 0;
 944         struct ref_lock *lock;
 945         struct stat loginfo;
 946         int log = !lstat(git_path("logs/%s", oldref), &loginfo);
 947
 948         if (S_ISLNK(loginfo.st_mode))
 949                 return error("reflog for %s is a symlink", oldref);
 950
 951         if (!resolve_ref(oldref, orig_sha1, 1, &flag))
 952                 return error("refname %s not found", oldref);
 953
 954         if (!is_refname_available(newref, oldref, get_packed_refs(), 0))
 955                 return 1;
 956
 957         if (!is_refname_available(newref, oldref, get_loose_refs(), 0))
 958                 return 1;
 959
 960         lock = lock_ref_sha1_basic(renamed_ref, NULL, 0, NULL);
 961         if (!lock)
 962                 return error("unable to lock %s", renamed_ref);
 963         lock->force_write = 1;
 964         if (write_ref_sha1(lock, orig_sha1, logmsg))
 965                 return error("unable to save current sha1 in %s", renamed_ref);
 966
 967         if (log && rename(git_path("logs/%s", oldref), git_path("tmp-renamed-log")))
 968                 return error("unable to move logfile logs/%s to tmp-renamed-log: %s",
 969                         oldref, strerror(errno));
 970
 971         if (delete_ref(oldref, orig_sha1)) {
 972                 error("unable to delete old %s", oldref);
 973                 goto rollback;
 974         }
 975
 976         if (resolve_ref(newref, sha1, 1, &flag) && delete_ref(newref, sha1)) {
 977                 if (errno==EISDIR) {
 978                         if (remove_empty_directories(git_path("%s", newref))) {
 979                                 error("Directory not empty: %s", newref);
 980                                 goto rollback;
 981                         }
 982                 } else {
 983                         error("unable to delete existing %s", newref);
 984                         goto rollback;
 985                 }
 986         }
 987
 988         if (log && safe_create_leading_directories(git_path("logs/%s", newref))) {
 989                 error("unable to create directory for %s", newref);
 990                 goto rollback;
 991         }
 992
 993  retry:
 994         if (log && rename(git_path("tmp-renamed-log"), git_path("logs/%s", newref))) {
 995                 if (errno==EISDIR || errno==ENOTDIR) {
 996                         /*
 997                          * rename(a, b) when b is an existing
 998                          * directory ought to result in ISDIR, but
 999                          * Solaris 5.8 gives ENOTDIR.  Sheesh.
1000                          */
1001                         if (remove_empty_directories(git_path("logs/%s", newref))) {
1002                                 error("Directory not empty: logs/%s", newref);
1003                                 goto rollback;
1004                         }
1005                         goto retry;
1006                 } else {
1007                         error("unable to move logfile tmp-renamed-log to logs/%s: %s",
1008                                 newref, strerror(errno));
1009                         goto rollback;
1010                 }
1011         }
1012         logmoved = log;
1013
1014         lock = lock_ref_sha1_basic(newref, NULL, 0, NULL);
1015         if (!lock) {
1016                 error("unable to lock %s for update", newref);
1017                 goto rollback;
1018         }
1019
1020         lock->force_write = 1;
1021         hashcpy(lock->old_sha1, orig_sha1);
1022         if (write_ref_sha1(lock, orig_sha1, logmsg)) {
1023                 error("unable to write current sha1 into %s", newref);
1024                 goto rollback;
1025         }
1026
1027         return 0;
1028
1029  rollback:
1030         lock = lock_ref_sha1_basic(oldref, NULL, 0, NULL);
1031         if (!lock) {
1032                 error("unable to lock %s for rollback", oldref);
1033                 goto rollbacklog;
1034         }
1035
1036         lock->force_write = 1;
1037         flag = log_all_ref_updates;
1038         log_all_ref_updates = 0;
1039         if (write_ref_sha1(lock, orig_sha1, NULL))
1040                 error("unable to write current sha1 into %s", oldref);
1041         log_all_ref_updates = flag;
1042
1043  rollbacklog:
1044         if (logmoved && rename(git_path("logs/%s", newref), git_path("logs/%s", oldref)))
1045                 error("unable to restore logfile %s from %s: %s",
1046                         oldref, newref, strerror(errno));
1047         if (!logmoved && log &&
1048             rename(git_path("tmp-renamed-log"), git_path("logs/%s", oldref)))
1049                 error("unable to restore logfile %s from tmp-renamed-log: %s",
1050                         oldref, strerror(errno));
1051
1052         return 1;
1053 }
1054
1055 int close_ref(struct ref_lock *lock)
1056 {
1057         if (close_lock_file(lock->lk))
1058                 return -1;
1059         lock->lock_fd = -1;
1060         return 0;
1061 }
1062
1063 int commit_ref(struct ref_lock *lock)
1064 {
1065         if (commit_lock_file(lock->lk))
1066                 return -1;
1067         lock->lock_fd = -1;
1068         return 0;
1069 }
1070
1071 void unlock_ref(struct ref_lock *lock)
1072 {
1073         /* Do not free lock->lk -- atexit() still looks at them */
1074         if (lock->lk)
1075                 rollback_lock_file(lock->lk);
1076         free(lock->ref_name);
1077         free(lock->orig_ref_name);
1078         free(lock);
1079 }
1080
1081 /*
1082  * copy the reflog message msg to buf, which has been allocated sufficiently
1083  * large, while cleaning up the whitespaces.  Especially, convert LF to space,
1084  * because reflog file is one line per entry.
1085  */
1086 static int copy_msg(char *buf, const char *msg)
1087 {
1088         char *cp = buf;
1089         char c;
1090         int wasspace = 1;
1091
1092         *cp++ = '\t';
1093         while ((c = *msg++)) {
1094                 if (wasspace && isspace(c))
1095                         continue;
1096                 wasspace = isspace(c);
1097                 if (wasspace)
1098                         c = ' ';
1099                 *cp++ = c;
1100         }
1101         while (buf < cp && isspace(cp[-1]))
1102                 cp--;
1103         *cp++ = '\n';
1104         return cp - buf;
1105 }
1106
1107 static int log_ref_write(const char *ref_name, const unsigned char *old_sha1,
1108                          const unsigned char *new_sha1, const char *msg)
1109 {
1110         int logfd, written, oflags = O_APPEND | O_WRONLY;
1111         unsigned maxlen, len;
1112         int msglen;
1113         char *log_file, *logrec;
1114         const char *committer;
1115
1116         if (log_all_ref_updates < 0)
1117                 log_all_ref_updates = !is_bare_repository();
1118
1119         log_file = git_path("logs/%s", ref_name);
1120
1121         if (log_all_ref_updates &&
1122             (!prefixcmp(ref_name, "refs/heads/") ||
1123              !prefixcmp(ref_name, "refs/remotes/") ||
1124              !strcmp(ref_name, "HEAD"))) {
1125                 if (safe_create_leading_directories(log_file) < 0)
1126                         return error("unable to create directory for %s",
1127                                      log_file);
1128                 oflags |= O_CREAT;
1129         }
1130
1131         logfd = open(log_file, oflags, 0666);
1132         if (logfd < 0) {
1133                 if (!(oflags & O_CREAT) && errno == ENOENT)
1134                         return 0;
1135
1136                 if ((oflags & O_CREAT) && errno == EISDIR) {
1137                         if (remove_empty_directories(log_file)) {
1138                                 return error("There are still logs under '%s'",
1139                                              log_file);
1140                         }
1141                         logfd = open(log_file, oflags, 0666);
1142                 }
1143
1144                 if (logfd < 0)
1145                         return error("Unable to append to %s: %s",
1146                                      log_file, strerror(errno));
1147         }
1148
1149         adjust_shared_perm(log_file);
1150
1151         msglen = msg ? strlen(msg) : 0;
1152         committer = git_committer_info(0);
1153         maxlen = strlen(committer) + msglen + 100;
1154         logrec = xmalloc(maxlen);
1155         len = sprintf(logrec, "%s %s %s\n",
1156                       sha1_to_hex(old_sha1),
1157                       sha1_to_hex(new_sha1),
1158                       committer);
1159         if (msglen)
1160                 len += copy_msg(logrec + len - 1, msg) - 1;
1161         written = len <= maxlen ? write_in_full(logfd, logrec, len) : -1;
1162         free(logrec);
1163         if (close(logfd) != 0 || written != len)
1164                 return error("Unable to append to %s", log_file);
1165         return 0;
1166 }
1167
1168 static int is_branch(const char *refname)
1169 {
1170         return !strcmp(refname, "HEAD") || !prefixcmp(refname, "refs/heads/");
1171 }
1172
1173 int write_ref_sha1(struct ref_lock *lock,
1174         const unsigned char *sha1, const char *logmsg)
1175 {
1176         static char term = '\n';
1177         struct object *o;
1178
1179         if (!lock)
1180                 return -1;
1181         if (!lock->force_write && !hashcmp(lock->old_sha1, sha1)) {
1182                 unlock_ref(lock);
1183                 return 0;
1184         }
1185         o = parse_object(sha1);
1186         if (!o) {
1187                 error("Trying to write ref %s with nonexistant object %s",
1188                         lock->ref_name, sha1_to_hex(sha1));
1189                 unlock_ref(lock);
1190                 return -1;
1191         }
1192         if (o->type != OBJ_COMMIT && is_branch(lock->ref_name)) {
1193                 error("Trying to write non-commit object %s to branch %s",
1194                         sha1_to_hex(sha1), lock->ref_name);
1195                 unlock_ref(lock);
1196                 return -1;
1197         }
1198         if (write_in_full(lock->lock_fd, sha1_to_hex(sha1), 40) != 40 ||
1199             write_in_full(lock->lock_fd, &term, 1) != 1
1200                 || close_ref(lock) < 0) {
1201                 error("Couldn't write %s", lock->lk->filename);
1202                 unlock_ref(lock);
1203                 return -1;
1204         }
1205         invalidate_cached_refs();
1206         if (log_ref_write(lock->ref_name, lock->old_sha1, sha1, logmsg) < 0 ||
1207             (strcmp(lock->ref_name, lock->orig_ref_name) &&
1208              log_ref_write(lock->orig_ref_name, lock->old_sha1, sha1, logmsg) < 0)) {
1209                 unlock_ref(lock);
1210                 return -1;
1211         }
1212         if (strcmp(lock->orig_ref_name, "HEAD") != 0) {
1213                 /*
1214                  * Special hack: If a branch is updated directly and HEAD
1215                  * points to it (may happen on the remote side of a push
1216                  * for example) then logically the HEAD reflog should be
1217                  * updated too.
1218                  * A generic solution implies reverse symref information,
1219                  * but finding all symrefs pointing to the given branch
1220                  * would be rather costly for this rare event (the direct
1221                  * update of a branch) to be worth it.  So let's cheat and
1222                  * check with HEAD only which should cover 99% of all usage
1223                  * scenarios (even 100% of the default ones).
1224                  */
1225                 unsigned char head_sha1[20];
1226                 int head_flag;
1227                 const char *head_ref;
1228                 head_ref = resolve_ref("HEAD", head_sha1, 1, &head_flag);
1229                 if (head_ref && (head_flag & REF_ISSYMREF) &&
1230                     !strcmp(head_ref, lock->ref_name))
1231                         log_ref_write("HEAD", lock->old_sha1, sha1, logmsg);
1232         }
1233         if (commit_ref(lock)) {
1234                 error("Couldn't set %s", lock->ref_name);
1235                 unlock_ref(lock);
1236                 return -1;
1237         }
1238         unlock_ref(lock);
1239         return 0;
1240 }
1241
1242 int create_symref(const char *ref_target, const char *refs_heads_master,
1243                   const char *logmsg)
1244 {
1245         const char *lockpath;
1246         char ref[1000];
1247         int fd, len, written;
1248         char *git_HEAD = xstrdup(git_path("%s", ref_target));
1249         unsigned char old_sha1[20], new_sha1[20];
1250
1251         if (logmsg && read_ref(ref_target, old_sha1))
1252                 hashclr(old_sha1);
1253
1254         if (safe_create_leading_directories(git_HEAD) < 0)
1255                 return error("unable to create directory for %s", git_HEAD);
1256
1257 #ifndef NO_SYMLINK_HEAD
1258         if (prefer_symlink_refs) {
1259                 unlink(git_HEAD);
1260                 if (!symlink(refs_heads_master, git_HEAD))
1261                         goto done;
1262                 fprintf(stderr, "no symlink - falling back to symbolic ref\n");
1263         }
1264 #endif
1265
1266         len = snprintf(ref, sizeof(ref), "ref: %s\n", refs_heads_master);
1267         if (sizeof(ref) <= len) {
1268                 error("refname too long: %s", refs_heads_master);
1269                 goto error_free_return;
1270         }
1271         lockpath = mkpath("%s.lock", git_HEAD);
1272         fd = open(lockpath, O_CREAT | O_EXCL | O_WRONLY, 0666);
1273         if (fd < 0) {
1274                 error("Unable to open %s for writing", lockpath);
1275                 goto error_free_return;
1276         }
1277         written = write_in_full(fd, ref, len);
1278         if (close(fd) != 0 || written != len) {
1279                 error("Unable to write to %s", lockpath);
1280                 goto error_unlink_return;
1281         }
1282         if (rename(lockpath, git_HEAD) < 0) {
1283                 error("Unable to create %s", git_HEAD);
1284                 goto error_unlink_return;
1285         }
1286         if (adjust_shared_perm(git_HEAD)) {
1287                 error("Unable to fix permissions on %s", lockpath);
1288         error_unlink_return:
1289                 unlink(lockpath);
1290         error_free_return:
1291                 free(git_HEAD);
1292                 return -1;
1293         }
1294
1295 #ifndef NO_SYMLINK_HEAD
1296         done:
1297 #endif
1298         if (logmsg && !read_ref(refs_heads_master, new_sha1))
1299                 log_ref_write(ref_target, old_sha1, new_sha1, logmsg);
1300
1301         free(git_HEAD);
1302         return 0;
1303 }
1304
1305 static char *ref_msg(const char *line, const char *endp)
1306 {
1307         const char *ep;
1308         line += 82;
1309         ep = memchr(line, '\n', endp - line);
1310         if (!ep)
1311                 ep = endp;
1312         return xmemdupz(line, ep - line);
1313 }
1314
1315 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)
1316 {
1317         const char *logfile, *logdata, *logend, *rec, *lastgt, *lastrec;
1318         char *tz_c;
1319         int logfd, tz, reccnt = 0;
1320         struct stat st;
1321         unsigned long date;
1322         unsigned char logged_sha1[20];
1323         void *log_mapped;
1324         size_t mapsz;
1325
1326         logfile = git_path("logs/%s", ref);
1327         logfd = open(logfile, O_RDONLY, 0);
1328         if (logfd < 0)
1329                 die("Unable to read log %s: %s", logfile, strerror(errno));
1330         fstat(logfd, &st);
1331         if (!st.st_size)
1332                 die("Log %s is empty.", logfile);
1333         mapsz = xsize_t(st.st_size);
1334         log_mapped = xmmap(NULL, mapsz, PROT_READ, MAP_PRIVATE, logfd, 0);
1335         logdata = log_mapped;
1336         close(logfd);
1337
1338         lastrec = NULL;
1339         rec = logend = logdata + st.st_size;
1340         while (logdata < rec) {
1341                 reccnt++;
1342                 if (logdata < rec && *(rec-1) == '\n')
1343                         rec--;
1344                 lastgt = NULL;
1345                 while (logdata < rec && *(rec-1) != '\n') {
1346                         rec--;
1347                         if (*rec == '>')
1348                                 lastgt = rec;
1349                 }
1350                 if (!lastgt)
1351                         die("Log %s is corrupt.", logfile);
1352                 date = strtoul(lastgt + 1, &tz_c, 10);
1353                 if (date <= at_time || cnt == 0) {
1354                         tz = strtoul(tz_c, NULL, 10);
1355                         if (msg)
1356                                 *msg = ref_msg(rec, logend);
1357                         if (cutoff_time)
1358                                 *cutoff_time = date;
1359                         if (cutoff_tz)
1360                                 *cutoff_tz = tz;
1361                         if (cutoff_cnt)
1362                                 *cutoff_cnt = reccnt - 1;
1363                         if (lastrec) {
1364                                 if (get_sha1_hex(lastrec, logged_sha1))
1365                                         die("Log %s is corrupt.", logfile);
1366                                 if (get_sha1_hex(rec + 41, sha1))
1367                                         die("Log %s is corrupt.", logfile);
1368                                 if (hashcmp(logged_sha1, sha1)) {
1369                                         fprintf(stderr,
1370                                                 "warning: Log %s has gap after %s.\n",
1371                                                 logfile, show_date(date, tz, DATE_RFC2822));
1372                                 }
1373                         }
1374                         else if (date == at_time) {
1375                                 if (get_sha1_hex(rec + 41, sha1))
1376                                         die("Log %s is corrupt.", logfile);
1377                         }
1378                         else {
1379                                 if (get_sha1_hex(rec + 41, logged_sha1))
1380                                         die("Log %s is corrupt.", logfile);
1381                                 if (hashcmp(logged_sha1, sha1)) {
1382                                         fprintf(stderr,
1383                                                 "warning: Log %s unexpectedly ended on %s.\n",
1384                                                 logfile, show_date(date, tz, DATE_RFC2822));
1385                                 }
1386                         }
1387                         munmap(log_mapped, mapsz);
1388                         return 0;
1389                 }
1390                 lastrec = rec;
1391                 if (cnt > 0)
1392                         cnt--;
1393         }
1394
1395         rec = logdata;
1396         while (rec < logend && *rec != '>' && *rec != '\n')
1397                 rec++;
1398         if (rec == logend || *rec == '\n')
1399                 die("Log %s is corrupt.", logfile);
1400         date = strtoul(rec + 1, &tz_c, 10);
1401         tz = strtoul(tz_c, NULL, 10);
1402         if (get_sha1_hex(logdata, sha1))
1403                 die("Log %s is corrupt.", logfile);
1404         if (msg)
1405                 *msg = ref_msg(logdata, logend);
1406         munmap(log_mapped, mapsz);
1407
1408         if (cutoff_time)
1409                 *cutoff_time = date;
1410         if (cutoff_tz)
1411                 *cutoff_tz = tz;
1412         if (cutoff_cnt)
1413                 *cutoff_cnt = reccnt;
1414         return 1;
1415 }
1416
1417 int for_each_reflog_ent(const char *ref, each_reflog_ent_fn fn, void *cb_data)
1418 {
1419         const char *logfile;
1420         FILE *logfp;
1421         char buf[1024];
1422         int ret = 0;
1423
1424         logfile = git_path("logs/%s", ref);
1425         logfp = fopen(logfile, "r");
1426         if (!logfp)
1427                 return -1;
1428         while (fgets(buf, sizeof(buf), logfp)) {
1429                 unsigned char osha1[20], nsha1[20];
1430                 char *email_end, *message;
1431                 unsigned long timestamp;
1432                 int len, tz;
1433
1434                 /* old SP new SP name <email> SP time TAB msg LF */
1435                 len = strlen(buf);
1436                 if (len < 83 || buf[len-1] != '\n' ||
1437                     get_sha1_hex(buf, osha1) || buf[40] != ' ' ||
1438                     get_sha1_hex(buf + 41, nsha1) || buf[81] != ' ' ||
1439                     !(email_end = strchr(buf + 82, '>')) ||
1440                     email_end[1] != ' ' ||
1441                     !(timestamp = strtoul(email_end + 2, &message, 10)) ||
1442                     !message || message[0] != ' ' ||
1443                     (message[1] != '+' && message[1] != '-') ||
1444                     !isdigit(message[2]) || !isdigit(message[3]) ||
1445                     !isdigit(message[4]) || !isdigit(message[5]))
1446                         continue; /* corrupt? */
1447                 email_end[1] = '\0';
1448                 tz = strtol(message + 1, NULL, 10);
1449                 if (message[6] != '\t')
1450                         message += 6;
1451                 else
1452                         message += 7;
1453                 ret = fn(osha1, nsha1, buf+82, timestamp, tz, message, cb_data);
1454                 if (ret)
1455                         break;
1456         }
1457         fclose(logfp);
1458         return ret;
1459 }
1460
1461 static int do_for_each_reflog(const char *base, each_ref_fn fn, void *cb_data)
1462 {
1463         DIR *dir = opendir(git_path("logs/%s", base));
1464         int retval = 0;
1465
1466         if (dir) {
1467                 struct dirent *de;
1468                 int baselen = strlen(base);
1469                 char *log = xmalloc(baselen + 257);
1470
1471                 memcpy(log, base, baselen);
1472                 if (baselen && base[baselen-1] != '/')
1473                         log[baselen++] = '/';
1474
1475                 while ((de = readdir(dir)) != NULL) {
1476                         struct stat st;
1477                         int namelen;
1478
1479                         if (de->d_name[0] == '.')
1480                                 continue;
1481                         namelen = strlen(de->d_name);
1482                         if (namelen > 255)
1483                                 continue;
1484                         if (has_extension(de->d_name, ".lock"))
1485                                 continue;
1486                         memcpy(log + baselen, de->d_name, namelen+1);
1487                         if (stat(git_path("logs/%s", log), &st) < 0)
1488                                 continue;
1489                         if (S_ISDIR(st.st_mode)) {
1490                                 retval = do_for_each_reflog(log, fn, cb_data);
1491                         } else {
1492                                 unsigned char sha1[20];
1493                                 if (!resolve_ref(log, sha1, 0, NULL))
1494                                         retval = error("bad ref for %s", log);
1495                                 else
1496                                         retval = fn(log, sha1, 0, cb_data);
1497                         }
1498                         if (retval)
1499                                 break;
1500                 }
1501                 free(log);
1502                 closedir(dir);
1503         }
1504         else if (*base)
1505                 return errno;
1506         return retval;
1507 }
1508
1509 int for_each_reflog(each_ref_fn fn, void *cb_data)
1510 {
1511         return do_for_each_reflog("", fn, cb_data);
1512 }
1513
1514 int update_ref(const char *action, const char *refname,
1515                 const unsigned char *sha1, const unsigned char *oldval,
1516                 int flags, enum action_on_err onerr)
1517 {
1518         static struct ref_lock *lock;
1519         lock = lock_any_ref_for_update(refname, oldval, flags);
1520         if (!lock) {
1521                 const char *str = "Cannot lock the ref '%s'.";
1522                 switch (onerr) {
1523                 case MSG_ON_ERR: error(str, refname); break;
1524                 case DIE_ON_ERR: die(str, refname); break;
1525                 case QUIET_ON_ERR: break;
1526                 }
1527                 return 1;
1528         }
1529         if (write_ref_sha1(lock, sha1, action) < 0) {
1530                 const char *str = "Cannot update the ref '%s'.";
1531                 switch (onerr) {
1532                 case MSG_ON_ERR: error(str, refname); break;
1533                 case DIE_ON_ERR: die(str, refname); break;
1534                 case QUIET_ON_ERR: break;
1535                 }
1536                 return 1;
1537         }
1538         return 0;
1539 }
1540
1541 struct ref *find_ref_by_name(struct ref *list, const char *name)
1542 {
1543         for ( ; list; list = list->next)
1544                 if (!strcmp(list->name, name))
1545                         return list;
1546         return NULL;
1547 }