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         const char *tmp;
 369
 370         while (len && path[len-1] == '/')
 371                 len--;
 372         if (!len)
 373                 return -1;
 374         gitdir = xmalloc(len + MAXREFLEN + 8);
 375         memcpy(gitdir, path, len);
 376         memcpy(gitdir + len, "/.git", 6);
 377         len += 5;
 378
 379         tmp = read_gitfile_gently(gitdir);
 380         if (tmp) {
 381                 free(gitdir);
 382                 len = strlen(tmp);
 383                 gitdir = xmalloc(len + MAXREFLEN + 3);
 384                 memcpy(gitdir, tmp, len);
 385         }
 386         gitdir[len] = '/';
 387         gitdir[++len] = '\0';
 388         retval = resolve_gitlink_ref_recursive(gitdir, len, refname, result, 0);
 389         free(gitdir);
 390         return retval;
 391 }
 392
 393 const char *resolve_ref(const char *ref, unsigned char *sha1, int reading, int *flag)
 394 {
 395         int depth = MAXDEPTH;
 396         ssize_t len;
 397         char buffer[256];
 398         static char ref_buffer[256];
 399
 400         if (flag)
 401                 *flag = 0;
 402
 403         for (;;) {
 404                 char path[PATH_MAX];
 405                 struct stat st;
 406                 char *buf;
 407                 int fd;
 408
 409                 if (--depth < 0)
 410                         return NULL;
 411
 412                 git_snpath(path, sizeof(path), "%s", ref);
 413                 /* Special case: non-existing file.
 414                  * Not having the refs/heads/new-branch is OK
 415                  * if we are writing into it, so is .git/HEAD
 416                  * that points at refs/heads/master still to be
 417                  * born.  It is NOT OK if we are resolving for
 418                  * reading.
 419                  */
 420                 if (lstat(path, &st) < 0) {
 421                         struct ref_list *list = get_packed_refs();
 422                         while (list) {
 423                                 if (!strcmp(ref, list->name)) {
 424                                         hashcpy(sha1, list->sha1);
 425                                         if (flag)
 426                                                 *flag |= REF_ISPACKED;
 427                                         return ref;
 428                                 }
 429                                 list = list->next;
 430                         }
 431                         if (reading || errno != ENOENT)
 432                                 return NULL;
 433                         hashclr(sha1);
 434                         return ref;
 435                 }
 436
 437                 /* Follow "normalized" - ie "refs/.." symlinks by hand */
 438                 if (S_ISLNK(st.st_mode)) {
 439                         len = readlink(path, buffer, sizeof(buffer)-1);
 440                         if (len >= 5 && !memcmp("refs/", buffer, 5)) {
 441                                 buffer[len] = 0;
 442                                 strcpy(ref_buffer, buffer);
 443                                 ref = ref_buffer;
 444                                 if (flag)
 445                                         *flag |= REF_ISSYMREF;
 446                                 continue;
 447                         }
 448                 }
 449
 450                 /* Is it a directory? */
 451                 if (S_ISDIR(st.st_mode)) {
 452                         errno = EISDIR;
 453                         return NULL;
 454                 }
 455
 456                 /*
 457                  * Anything else, just open it and try to use it as
 458                  * a ref
 459                  */
 460                 fd = open(path, O_RDONLY);
 461                 if (fd < 0)
 462                         return NULL;
 463                 len = read_in_full(fd, buffer, sizeof(buffer)-1);
 464                 close(fd);
 465
 466                 /*
 467                  * Is it a symbolic ref?
 468                  */
 469                 if (len < 4 || memcmp("ref:", buffer, 4))
 470                         break;
 471                 buf = buffer + 4;
 472                 len -= 4;
 473                 while (len && isspace(*buf))
 474                         buf++, len--;
 475                 while (len && isspace(buf[len-1]))
 476                         len--;
 477                 buf[len] = 0;
 478                 memcpy(ref_buffer, buf, len + 1);
 479                 ref = ref_buffer;
 480                 if (flag)
 481                         *flag |= REF_ISSYMREF;
 482         }
 483         if (len < 40 || get_sha1_hex(buffer, sha1))
 484                 return NULL;
 485         return ref;
 486 }
 487
 488 int read_ref(const char *ref, unsigned char *sha1)
 489 {
 490         if (resolve_ref(ref, sha1, 1, NULL))
 491                 return 0;
 492         return -1;
 493 }
 494
 495 static int do_one_ref(const char *base, each_ref_fn fn, int trim,
 496                       void *cb_data, struct ref_list *entry)
 497 {
 498         if (strncmp(base, entry->name, trim))
 499                 return 0;
 500         if (is_null_sha1(entry->sha1))
 501                 return 0;
 502         if (!has_sha1_file(entry->sha1)) {
 503                 error("%s does not point to a valid object!", entry->name);
 504                 return 0;
 505         }
 506         current_ref = entry;
 507         return fn(entry->name + trim, entry->sha1, entry->flag, cb_data);
 508 }
 509
 510 int peel_ref(const char *ref, unsigned char *sha1)
 511 {
 512         int flag;
 513         unsigned char base[20];
 514         struct object *o;
 515
 516         if (current_ref && (current_ref->name == ref
 517                 || !strcmp(current_ref->name, ref))) {
 518                 if (current_ref->flag & REF_KNOWS_PEELED) {
 519                         hashcpy(sha1, current_ref->peeled);
 520                         return 0;
 521                 }
 522                 hashcpy(base, current_ref->sha1);
 523                 goto fallback;
 524         }
 525
 526         if (!resolve_ref(ref, base, 1, &flag))
 527                 return -1;
 528
 529         if ((flag & REF_ISPACKED)) {
 530                 struct ref_list *list = get_packed_refs();
 531
 532                 while (list) {
 533                         if (!strcmp(list->name, ref)) {
 534                                 if (list->flag & REF_KNOWS_PEELED) {
 535                                         hashcpy(sha1, list->peeled);
 536                                         return 0;
 537                                 }
 538                                 /* older pack-refs did not leave peeled ones */
 539                                 break;
 540                         }
 541                         list = list->next;
 542                 }
 543         }
 544
 545 fallback:
 546         o = parse_object(base);
 547         if (o && o->type == OBJ_TAG) {
 548                 o = deref_tag(o, ref, 0);
 549                 if (o) {
 550                         hashcpy(sha1, o->sha1);
 551                         return 0;
 552                 }
 553         }
 554         return -1;
 555 }
 556
 557 static int do_for_each_ref(const char *base, each_ref_fn fn, int trim,
 558                            void *cb_data)
 559 {
 560         int retval = 0;
 561         struct ref_list *packed = get_packed_refs();
 562         struct ref_list *loose = get_loose_refs();
 563
 564         struct ref_list *extra;
 565
 566         for (extra = extra_refs; extra; extra = extra->next)
 567                 retval = do_one_ref(base, fn, trim, cb_data, extra);
 568
 569         while (packed && loose) {
 570                 struct ref_list *entry;
 571                 int cmp = strcmp(packed->name, loose->name);
 572                 if (!cmp) {
 573                         packed = packed->next;
 574                         continue;
 575                 }
 576                 if (cmp > 0) {
 577                         entry = loose;
 578                         loose = loose->next;
 579                 } else {
 580                         entry = packed;
 581                         packed = packed->next;
 582                 }
 583                 retval = do_one_ref(base, fn, trim, cb_data, entry);
 584                 if (retval)
 585                         goto end_each;
 586         }
 587
 588         for (packed = packed ? packed : loose; packed; packed = packed->next) {
 589                 retval = do_one_ref(base, fn, trim, cb_data, packed);
 590                 if (retval)
 591                         goto end_each;
 592         }
 593
 594 end_each:
 595         current_ref = NULL;
 596         return retval;
 597 }
 598
 599 int head_ref(each_ref_fn fn, void *cb_data)
 600 {
 601         unsigned char sha1[20];
 602         int flag;
 603
 604         if (resolve_ref("HEAD", sha1, 1, &flag))
 605                 return fn("HEAD", sha1, flag, cb_data);
 606         return 0;
 607 }
 608
 609 int for_each_ref(each_ref_fn fn, void *cb_data)
 610 {
 611         return do_for_each_ref("refs/", fn, 0, cb_data);
 612 }
 613
 614 int for_each_tag_ref(each_ref_fn fn, void *cb_data)
 615 {
 616         return do_for_each_ref("refs/tags/", fn, 10, cb_data);
 617 }
 618
 619 int for_each_branch_ref(each_ref_fn fn, void *cb_data)
 620 {
 621         return do_for_each_ref("refs/heads/", fn, 11, cb_data);
 622 }
 623
 624 int for_each_remote_ref(each_ref_fn fn, void *cb_data)
 625 {
 626         return do_for_each_ref("refs/remotes/", fn, 13, cb_data);
 627 }
 628
 629 /*
 630  * Make sure "ref" is something reasonable to have under ".git/refs/";
 631  * We do not like it if:
 632  *
 633  * - any path component of it begins with ".", or
 634  * - it has double dots "..", or
 635  * - it has ASCII control character, "~", "^", ":" or SP, anywhere, or
 636  * - it ends with a "/".
 637  */
 638
 639 static inline int bad_ref_char(int ch)
 640 {
 641         if (((unsigned) ch) <= ' ' ||
 642             ch == '~' || ch == '^' || ch == ':')
 643                 return 1;
 644         /* 2.13 Pattern Matching Notation */
 645         if (ch == '?' || ch == '[') /* Unsupported */
 646                 return 1;
 647         if (ch == '*') /* Supported at the end */
 648                 return 2;
 649         return 0;
 650 }
 651
 652 int check_ref_format(const char *ref)
 653 {
 654         int ch, level, bad_type;
 655         const char *cp = ref;
 656
 657         level = 0;
 658         while (1) {
 659                 while ((ch = *cp++) == '/')
 660                         ; /* tolerate duplicated slashes */
 661                 if (!ch)
 662                         /* should not end with slashes */
 663                         return CHECK_REF_FORMAT_ERROR;
 664
 665                 /* we are at the beginning of the path component */
 666                 if (ch == '.')
 667                         return CHECK_REF_FORMAT_ERROR;
 668                 bad_type = bad_ref_char(ch);
 669                 if (bad_type) {
 670                         return (bad_type == 2 && !*cp)
 671                                 ? CHECK_REF_FORMAT_WILDCARD
 672                                 : CHECK_REF_FORMAT_ERROR;
 673                 }
 674
 675                 /* scan the rest of the path component */
 676                 while ((ch = *cp++) != 0) {
 677                         bad_type = bad_ref_char(ch);
 678                         if (bad_type) {
 679                                 return (bad_type == 2 && !*cp)
 680                                         ? CHECK_REF_FORMAT_WILDCARD
 681                                         : CHECK_REF_FORMAT_ERROR;
 682                         }
 683                         if (ch == '/')
 684                                 break;
 685                         if (ch == '.' && *cp == '.')
 686                                 return CHECK_REF_FORMAT_ERROR;
 687                 }
 688                 level++;
 689                 if (!ch) {
 690                         if (level < 2)
 691                                 return CHECK_REF_FORMAT_ONELEVEL;
 692                         return CHECK_REF_FORMAT_OK;
 693                 }
 694         }
 695 }
 696
 697 const char *ref_rev_parse_rules[] = {
 698         "%.*s",
 699         "refs/%.*s",
 700         "refs/tags/%.*s",
 701         "refs/heads/%.*s",
 702         "refs/remotes/%.*s",
 703         "refs/remotes/%.*s/HEAD",
 704         NULL
 705 };
 706
 707 const char *ref_fetch_rules[] = {
 708         "%.*s",
 709         "refs/%.*s",
 710         "refs/heads/%.*s",
 711         NULL
 712 };
 713
 714 int refname_match(const char *abbrev_name, const char *full_name, const char **rules)
 715 {
 716         const char **p;
 717         const int abbrev_name_len = strlen(abbrev_name);
 718
 719         for (p = rules; *p; p++) {
 720                 if (!strcmp(full_name, mkpath(*p, abbrev_name_len, abbrev_name))) {
 721                         return 1;
 722                 }
 723         }
 724
 725         return 0;
 726 }
 727
 728 static struct ref_lock *verify_lock(struct ref_lock *lock,
 729         const unsigned char *old_sha1, int mustexist)
 730 {
 731         if (!resolve_ref(lock->ref_name, lock->old_sha1, mustexist, NULL)) {
 732                 error("Can't verify ref %s", lock->ref_name);
 733                 unlock_ref(lock);
 734                 return NULL;
 735         }
 736         if (hashcmp(lock->old_sha1, old_sha1)) {
 737                 error("Ref %s is at %s but expected %s", lock->ref_name,
 738                         sha1_to_hex(lock->old_sha1), sha1_to_hex(old_sha1));
 739                 unlock_ref(lock);
 740                 return NULL;
 741         }
 742         return lock;
 743 }
 744
 745 static int remove_empty_directories(const char *file)
 746 {
 747         /* we want to create a file but there is a directory there;
 748          * if that is an empty directory (or a directory that contains
 749          * only empty directories), remove them.
 750          */
 751         struct strbuf path;
 752         int result;
 753
 754         strbuf_init(&path, 20);
 755         strbuf_addstr(&path, file);
 756
 757         result = remove_dir_recursively(&path, 1);
 758
 759         strbuf_release(&path);
 760
 761         return result;
 762 }
 763
 764 static int is_refname_available(const char *ref, const char *oldref,
 765                                 struct ref_list *list, int quiet)
 766 {
 767         int namlen = strlen(ref); /* e.g. 'foo/bar' */
 768         while (list) {
 769                 /* list->name could be 'foo' or 'foo/bar/baz' */
 770                 if (!oldref || strcmp(oldref, list->name)) {
 771                         int len = strlen(list->name);
 772                         int cmplen = (namlen < len) ? namlen : len;
 773                         const char *lead = (namlen < len) ? list->name : ref;
 774                         if (!strncmp(ref, list->name, cmplen) &&
 775                             lead[cmplen] == '/') {
 776                                 if (!quiet)
 777                                         error("'%s' exists; cannot create '%s'",
 778                                               list->name, ref);
 779                                 return 0;
 780                         }
 781                 }
 782                 list = list->next;
 783         }
 784         return 1;
 785 }
 786
 787 static struct ref_lock *lock_ref_sha1_basic(const char *ref, const unsigned char *old_sha1, int flags, int *type_p)
 788 {
 789         char *ref_file;
 790         const char *orig_ref = ref;
 791         struct ref_lock *lock;
 792         struct stat st;
 793         int last_errno = 0;
 794         int type, lflags;
 795         int mustexist = (old_sha1 && !is_null_sha1(old_sha1));
 796
 797         lock = xcalloc(1, sizeof(struct ref_lock));
 798         lock->lock_fd = -1;
 799
 800         ref = resolve_ref(ref, lock->old_sha1, mustexist, &type);
 801         if (!ref && errno == EISDIR) {
 802                 /* we are trying to lock foo but we used to
 803                  * have foo/bar which now does not exist;
 804                  * it is normal for the empty directory 'foo'
 805                  * to remain.
 806                  */
 807                 ref_file = git_path("%s", orig_ref);
 808                 if (remove_empty_directories(ref_file)) {
 809                         last_errno = errno;
 810                         error("there are still refs under '%s'", orig_ref);
 811                         goto error_return;
 812                 }
 813                 ref = resolve_ref(orig_ref, lock->old_sha1, mustexist, &type);
 814         }
 815         if (type_p)
 816             *type_p = type;
 817         if (!ref) {
 818                 last_errno = errno;
 819                 error("unable to resolve reference %s: %s",
 820                         orig_ref, strerror(errno));
 821                 goto error_return;
 822         }
 823         /* When the ref did not exist and we are creating it,
 824          * make sure there is no existing ref that is packed
 825          * whose name begins with our refname, nor a ref whose
 826          * name is a proper prefix of our refname.
 827          */
 828         if (is_null_sha1(lock->old_sha1) &&
 829             !is_refname_available(ref, NULL, get_packed_refs(), 0))
 830                 goto error_return;
 831
 832         lock->lk = xcalloc(1, sizeof(struct lock_file));
 833
 834         lflags = LOCK_DIE_ON_ERROR;
 835         if (flags & REF_NODEREF) {
 836                 ref = orig_ref;
 837                 lflags |= LOCK_NODEREF;
 838         }
 839         lock->ref_name = xstrdup(ref);
 840         lock->orig_ref_name = xstrdup(orig_ref);
 841         ref_file = git_path("%s", ref);
 842         if (lstat(ref_file, &st) && errno == ENOENT)
 843                 lock->force_write = 1;
 844         if ((flags & REF_NODEREF) && (type & REF_ISSYMREF))
 845                 lock->force_write = 1;
 846
 847         if (safe_create_leading_directories(ref_file)) {
 848                 last_errno = errno;
 849                 error("unable to create directory for %s", ref_file);
 850                 goto error_return;
 851         }
 852
 853         lock->lock_fd = hold_lock_file_for_update(lock->lk, ref_file, lflags);
 854         return old_sha1 ? verify_lock(lock, old_sha1, mustexist) : lock;
 855
 856  error_return:
 857         unlock_ref(lock);
 858         errno = last_errno;
 859         return NULL;
 860 }
 861
 862 struct ref_lock *lock_ref_sha1(const char *ref, const unsigned char *old_sha1)
 863 {
 864         char refpath[PATH_MAX];
 865         if (check_ref_format(ref))
 866                 return NULL;
 867         strcpy(refpath, mkpath("refs/%s", ref));
 868         return lock_ref_sha1_basic(refpath, old_sha1, 0, NULL);
 869 }
 870
 871 struct ref_lock *lock_any_ref_for_update(const char *ref, const unsigned char *old_sha1, int flags)
 872 {
 873         switch (check_ref_format(ref)) {
 874         default:
 875                 return NULL;
 876         case 0:
 877         case CHECK_REF_FORMAT_ONELEVEL:
 878                 return lock_ref_sha1_basic(ref, old_sha1, flags, NULL);
 879         }
 880 }
 881
 882 static struct lock_file packlock;
 883
 884 static int repack_without_ref(const char *refname)
 885 {
 886         struct ref_list *list, *packed_ref_list;
 887         int fd;
 888         int found = 0;
 889
 890         packed_ref_list = get_packed_refs();
 891         for (list = packed_ref_list; list; list = list->next) {
 892                 if (!strcmp(refname, list->name)) {
 893                         found = 1;
 894                         break;
 895                 }
 896         }
 897         if (!found)
 898                 return 0;
 899         fd = hold_lock_file_for_update(&packlock, git_path("packed-refs"), 0);
 900         if (fd < 0)
 901                 return error("cannot delete '%s' from packed refs", refname);
 902
 903         for (list = packed_ref_list; list; list = list->next) {
 904                 char line[PATH_MAX + 100];
 905                 int len;
 906
 907                 if (!strcmp(refname, list->name))
 908                         continue;
 909                 len = snprintf(line, sizeof(line), "%s %s\n",
 910                                sha1_to_hex(list->sha1), list->name);
 911                 /* this should not happen but just being defensive */
 912                 if (len > sizeof(line))
 913                         die("too long a refname '%s'", list->name);
 914                 write_or_die(fd, line, len);
 915         }
 916         return commit_lock_file(&packlock);
 917 }
 918
 919 int delete_ref(const char *refname, const unsigned char *sha1, int delopt)
 920 {
 921         struct ref_lock *lock;
 922         int err, i = 0, ret = 0, flag = 0;
 923
 924         lock = lock_ref_sha1_basic(refname, sha1, 0, &flag);
 925         if (!lock)
 926                 return 1;
 927         if (!(flag & REF_ISPACKED) || flag & REF_ISSYMREF) {
 928                 /* loose */
 929                 const char *path;
 930
 931                 if (!(delopt & REF_NODEREF)) {
 932                         i = strlen(lock->lk->filename) - 5; /* .lock */
 933                         lock->lk->filename[i] = 0;
 934                         path = lock->lk->filename;
 935                 } else {
 936                         path = git_path(refname);
 937                 }
 938                 err = unlink(path);
 939                 if (err && errno != ENOENT) {
 940                         ret = 1;
 941                         error("unlink(%s) failed: %s",
 942                               path, strerror(errno));
 943                 }
 944                 if (!(delopt & REF_NODEREF))
 945                         lock->lk->filename[i] = '.';
 946         }
 947         /* removing the loose one could have resurrected an earlier
 948          * packed one.  Also, if it was not loose we need to repack
 949          * without it.
 950          */
 951         ret |= repack_without_ref(refname);
 952
 953         err = unlink(git_path("logs/%s", lock->ref_name));
 954         if (err && errno != ENOENT)
 955                 fprintf(stderr, "warning: unlink(%s) failed: %s",
 956                         git_path("logs/%s", lock->ref_name), strerror(errno));
 957         invalidate_cached_refs();
 958         unlock_ref(lock);
 959         return ret;
 960 }
 961
 962 int rename_ref(const char *oldref, const char *newref, const char *logmsg)
 963 {
 964         static const char renamed_ref[] = "RENAMED-REF";
 965         unsigned char sha1[20], orig_sha1[20];
 966         int flag = 0, logmoved = 0;
 967         struct ref_lock *lock;
 968         struct stat loginfo;
 969         int log = !lstat(git_path("logs/%s", oldref), &loginfo);
 970         const char *symref = NULL;
 971
 972         if (log && S_ISLNK(loginfo.st_mode))
 973                 return error("reflog for %s is a symlink", oldref);
 974
 975         symref = resolve_ref(oldref, orig_sha1, 1, &flag);
 976         if (flag & REF_ISSYMREF)
 977                 return error("refname %s is a symbolic ref, renaming it is not supported",
 978                         oldref);
 979         if (!symref)
 980                 return error("refname %s not found", oldref);
 981
 982         if (!is_refname_available(newref, oldref, get_packed_refs(), 0))
 983                 return 1;
 984
 985         if (!is_refname_available(newref, oldref, get_loose_refs(), 0))
 986                 return 1;
 987
 988         lock = lock_ref_sha1_basic(renamed_ref, NULL, 0, NULL);
 989         if (!lock)
 990                 return error("unable to lock %s", renamed_ref);
 991         lock->force_write = 1;
 992         if (write_ref_sha1(lock, orig_sha1, logmsg))
 993                 return error("unable to save current sha1 in %s", renamed_ref);
 994
 995         if (log && rename(git_path("logs/%s", oldref), git_path("tmp-renamed-log")))
 996                 return error("unable to move logfile logs/%s to tmp-renamed-log: %s",
 997                         oldref, strerror(errno));
 998
 999         if (delete_ref(oldref, orig_sha1, REF_NODEREF)) {
1000                 error("unable to delete old %s", oldref);
1001                 goto rollback;
1002         }
1003
1004         if (resolve_ref(newref, sha1, 1, &flag) && delete_ref(newref, sha1, REF_NODEREF)) {
1005                 if (errno==EISDIR) {
1006                         if (remove_empty_directories(git_path("%s", newref))) {
1007                                 error("Directory not empty: %s", newref);
1008                                 goto rollback;
1009                         }
1010                 } else {
1011                         error("unable to delete existing %s", newref);
1012                         goto rollback;
1013                 }
1014         }
1015
1016         if (log && safe_create_leading_directories(git_path("logs/%s", newref))) {
1017                 error("unable to create directory for %s", newref);
1018                 goto rollback;
1019         }
1020
1021  retry:
1022         if (log && rename(git_path("tmp-renamed-log"), git_path("logs/%s", newref))) {
1023                 if (errno==EISDIR || errno==ENOTDIR) {
1024                         /*
1025                          * rename(a, b) when b is an existing
1026                          * directory ought to result in ISDIR, but
1027                          * Solaris 5.8 gives ENOTDIR.  Sheesh.
1028                          */
1029                         if (remove_empty_directories(git_path("logs/%s", newref))) {
1030                                 error("Directory not empty: logs/%s", newref);
1031                                 goto rollback;
1032                         }
1033                         goto retry;
1034                 } else {
1035                         error("unable to move logfile tmp-renamed-log to logs/%s: %s",
1036                                 newref, strerror(errno));
1037                         goto rollback;
1038                 }
1039         }
1040         logmoved = log;
1041
1042         lock = lock_ref_sha1_basic(newref, NULL, 0, NULL);
1043         if (!lock) {
1044                 error("unable to lock %s for update", newref);
1045                 goto rollback;
1046         }
1047         lock->force_write = 1;
1048         hashcpy(lock->old_sha1, orig_sha1);
1049         if (write_ref_sha1(lock, orig_sha1, logmsg)) {
1050                 error("unable to write current sha1 into %s", newref);
1051                 goto rollback;
1052         }
1053
1054         return 0;
1055
1056  rollback:
1057         lock = lock_ref_sha1_basic(oldref, NULL, 0, NULL);
1058         if (!lock) {
1059                 error("unable to lock %s for rollback", oldref);
1060                 goto rollbacklog;
1061         }
1062
1063         lock->force_write = 1;
1064         flag = log_all_ref_updates;
1065         log_all_ref_updates = 0;
1066         if (write_ref_sha1(lock, orig_sha1, NULL))
1067                 error("unable to write current sha1 into %s", oldref);
1068         log_all_ref_updates = flag;
1069
1070  rollbacklog:
1071         if (logmoved && rename(git_path("logs/%s", newref), git_path("logs/%s", oldref)))
1072                 error("unable to restore logfile %s from %s: %s",
1073                         oldref, newref, strerror(errno));
1074         if (!logmoved && log &&
1075             rename(git_path("tmp-renamed-log"), git_path("logs/%s", oldref)))
1076                 error("unable to restore logfile %s from tmp-renamed-log: %s",
1077                         oldref, strerror(errno));
1078
1079         return 1;
1080 }
1081
1082 int close_ref(struct ref_lock *lock)
1083 {
1084         if (close_lock_file(lock->lk))
1085                 return -1;
1086         lock->lock_fd = -1;
1087         return 0;
1088 }
1089
1090 int commit_ref(struct ref_lock *lock)
1091 {
1092         if (commit_lock_file(lock->lk))
1093                 return -1;
1094         lock->lock_fd = -1;
1095         return 0;
1096 }
1097
1098 void unlock_ref(struct ref_lock *lock)
1099 {
1100         /* Do not free lock->lk -- atexit() still looks at them */
1101         if (lock->lk)
1102                 rollback_lock_file(lock->lk);
1103         free(lock->ref_name);
1104         free(lock->orig_ref_name);
1105         free(lock);
1106 }
1107
1108 /*
1109  * copy the reflog message msg to buf, which has been allocated sufficiently
1110  * large, while cleaning up the whitespaces.  Especially, convert LF to space,
1111  * because reflog file is one line per entry.
1112  */
1113 static int copy_msg(char *buf, const char *msg)
1114 {
1115         char *cp = buf;
1116         char c;
1117         int wasspace = 1;
1118
1119         *cp++ = '\t';
1120         while ((c = *msg++)) {
1121                 if (wasspace && isspace(c))
1122                         continue;
1123                 wasspace = isspace(c);
1124                 if (wasspace)
1125                         c = ' ';
1126                 *cp++ = c;
1127         }
1128         while (buf < cp && isspace(cp[-1]))
1129                 cp--;
1130         *cp++ = '\n';
1131         return cp - buf;
1132 }
1133
1134 static int log_ref_write(const char *ref_name, const unsigned char *old_sha1,
1135                          const unsigned char *new_sha1, const char *msg)
1136 {
1137         int logfd, written, oflags = O_APPEND | O_WRONLY;
1138         unsigned maxlen, len;
1139         int msglen;
1140         char log_file[PATH_MAX];
1141         char *logrec;
1142         const char *committer;
1143
1144         if (log_all_ref_updates < 0)
1145                 log_all_ref_updates = !is_bare_repository();
1146
1147         git_snpath(log_file, sizeof(log_file), "logs/%s", ref_name);
1148
1149         if (log_all_ref_updates &&
1150             (!prefixcmp(ref_name, "refs/heads/") ||
1151              !prefixcmp(ref_name, "refs/remotes/") ||
1152              !strcmp(ref_name, "HEAD"))) {
1153                 if (safe_create_leading_directories(log_file) < 0)
1154                         return error("unable to create directory for %s",
1155                                      log_file);
1156                 oflags |= O_CREAT;
1157         }
1158
1159         logfd = open(log_file, oflags, 0666);
1160         if (logfd < 0) {
1161                 if (!(oflags & O_CREAT) && errno == ENOENT)
1162                         return 0;
1163
1164                 if ((oflags & O_CREAT) && errno == EISDIR) {
1165                         if (remove_empty_directories(log_file)) {
1166                                 return error("There are still logs under '%s'",
1167                                              log_file);
1168                         }
1169                         logfd = open(log_file, oflags, 0666);
1170                 }
1171
1172                 if (logfd < 0)
1173                         return error("Unable to append to %s: %s",
1174                                      log_file, strerror(errno));
1175         }
1176
1177         adjust_shared_perm(log_file);
1178
1179         msglen = msg ? strlen(msg) : 0;
1180         committer = git_committer_info(0);
1181         maxlen = strlen(committer) + msglen + 100;
1182         logrec = xmalloc(maxlen);
1183         len = sprintf(logrec, "%s %s %s\n",
1184                       sha1_to_hex(old_sha1),
1185                       sha1_to_hex(new_sha1),
1186                       committer);
1187         if (msglen)
1188                 len += copy_msg(logrec + len - 1, msg) - 1;
1189         written = len <= maxlen ? write_in_full(logfd, logrec, len) : -1;
1190         free(logrec);
1191         if (close(logfd) != 0 || written != len)
1192                 return error("Unable to append to %s", log_file);
1193         return 0;
1194 }
1195
1196 static int is_branch(const char *refname)
1197 {
1198         return !strcmp(refname, "HEAD") || !prefixcmp(refname, "refs/heads/");
1199 }
1200
1201 int write_ref_sha1(struct ref_lock *lock,
1202         const unsigned char *sha1, const char *logmsg)
1203 {
1204         static char term = '\n';
1205         struct object *o;
1206
1207         if (!lock)
1208                 return -1;
1209         if (!lock->force_write && !hashcmp(lock->old_sha1, sha1)) {
1210                 unlock_ref(lock);
1211                 return 0;
1212         }
1213         o = parse_object(sha1);
1214         if (!o) {
1215                 error("Trying to write ref %s with nonexistant object %s",
1216                         lock->ref_name, sha1_to_hex(sha1));
1217                 unlock_ref(lock);
1218                 return -1;
1219         }
1220         if (o->type != OBJ_COMMIT && is_branch(lock->ref_name)) {
1221                 error("Trying to write non-commit object %s to branch %s",
1222                         sha1_to_hex(sha1), lock->ref_name);
1223                 unlock_ref(lock);
1224                 return -1;
1225         }
1226         if (write_in_full(lock->lock_fd, sha1_to_hex(sha1), 40) != 40 ||
1227             write_in_full(lock->lock_fd, &term, 1) != 1
1228                 || close_ref(lock) < 0) {
1229                 error("Couldn't write %s", lock->lk->filename);
1230                 unlock_ref(lock);
1231                 return -1;
1232         }
1233         invalidate_cached_refs();
1234         if (log_ref_write(lock->ref_name, lock->old_sha1, sha1, logmsg) < 0 ||
1235             (strcmp(lock->ref_name, lock->orig_ref_name) &&
1236              log_ref_write(lock->orig_ref_name, lock->old_sha1, sha1, logmsg) < 0)) {
1237                 unlock_ref(lock);
1238                 return -1;
1239         }
1240         if (strcmp(lock->orig_ref_name, "HEAD") != 0) {
1241                 /*
1242                  * Special hack: If a branch is updated directly and HEAD
1243                  * points to it (may happen on the remote side of a push
1244                  * for example) then logically the HEAD reflog should be
1245                  * updated too.
1246                  * A generic solution implies reverse symref information,
1247                  * but finding all symrefs pointing to the given branch
1248                  * would be rather costly for this rare event (the direct
1249                  * update of a branch) to be worth it.  So let's cheat and
1250                  * check with HEAD only which should cover 99% of all usage
1251                  * scenarios (even 100% of the default ones).
1252                  */
1253                 unsigned char head_sha1[20];
1254                 int head_flag;
1255                 const char *head_ref;
1256                 head_ref = resolve_ref("HEAD", head_sha1, 1, &head_flag);
1257                 if (head_ref && (head_flag & REF_ISSYMREF) &&
1258                     !strcmp(head_ref, lock->ref_name))
1259                         log_ref_write("HEAD", lock->old_sha1, sha1, logmsg);
1260         }
1261         if (commit_ref(lock)) {
1262                 error("Couldn't set %s", lock->ref_name);
1263                 unlock_ref(lock);
1264                 return -1;
1265         }
1266         unlock_ref(lock);
1267         return 0;
1268 }
1269
1270 int create_symref(const char *ref_target, const char *refs_heads_master,
1271                   const char *logmsg)
1272 {
1273         const char *lockpath;
1274         char ref[1000];
1275         int fd, len, written;
1276         char *git_HEAD = git_pathdup("%s", ref_target);
1277         unsigned char old_sha1[20], new_sha1[20];
1278
1279         if (logmsg && read_ref(ref_target, old_sha1))
1280                 hashclr(old_sha1);
1281
1282         if (safe_create_leading_directories(git_HEAD) < 0)
1283                 return error("unable to create directory for %s", git_HEAD);
1284
1285 #ifndef NO_SYMLINK_HEAD
1286         if (prefer_symlink_refs) {
1287                 unlink(git_HEAD);
1288                 if (!symlink(refs_heads_master, git_HEAD))
1289                         goto done;
1290                 fprintf(stderr, "no symlink - falling back to symbolic ref\n");
1291         }
1292 #endif
1293
1294         len = snprintf(ref, sizeof(ref), "ref: %s\n", refs_heads_master);
1295         if (sizeof(ref) <= len) {
1296                 error("refname too long: %s", refs_heads_master);
1297                 goto error_free_return;
1298         }
1299         lockpath = mkpath("%s.lock", git_HEAD);
1300         fd = open(lockpath, O_CREAT | O_EXCL | O_WRONLY, 0666);
1301         if (fd < 0) {
1302                 error("Unable to open %s for writing", lockpath);
1303                 goto error_free_return;
1304         }
1305         written = write_in_full(fd, ref, len);
1306         if (close(fd) != 0 || written != len) {
1307                 error("Unable to write to %s", lockpath);
1308                 goto error_unlink_return;
1309         }
1310         if (rename(lockpath, git_HEAD) < 0) {
1311                 error("Unable to create %s", git_HEAD);
1312                 goto error_unlink_return;
1313         }
1314         if (adjust_shared_perm(git_HEAD)) {
1315                 error("Unable to fix permissions on %s", lockpath);
1316         error_unlink_return:
1317                 unlink(lockpath);
1318         error_free_return:
1319                 free(git_HEAD);
1320                 return -1;
1321         }
1322
1323 #ifndef NO_SYMLINK_HEAD
1324         done:
1325 #endif
1326         if (logmsg && !read_ref(refs_heads_master, new_sha1))
1327                 log_ref_write(ref_target, old_sha1, new_sha1, logmsg);
1328
1329         free(git_HEAD);
1330         return 0;
1331 }
1332
1333 static char *ref_msg(const char *line, const char *endp)
1334 {
1335         const char *ep;
1336         line += 82;
1337         ep = memchr(line, '\n', endp - line);
1338         if (!ep)
1339                 ep = endp;
1340         return xmemdupz(line, ep - line);
1341 }
1342
1343 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)
1344 {
1345         const char *logfile, *logdata, *logend, *rec, *lastgt, *lastrec;
1346         char *tz_c;
1347         int logfd, tz, reccnt = 0;
1348         struct stat st;
1349         unsigned long date;
1350         unsigned char logged_sha1[20];
1351         void *log_mapped;
1352         size_t mapsz;
1353
1354         logfile = git_path("logs/%s", ref);
1355         logfd = open(logfile, O_RDONLY, 0);
1356         if (logfd < 0)
1357                 die("Unable to read log %s: %s", logfile, strerror(errno));
1358         fstat(logfd, &st);
1359         if (!st.st_size)
1360                 die("Log %s is empty.", logfile);
1361         mapsz = xsize_t(st.st_size);
1362         log_mapped = xmmap(NULL, mapsz, PROT_READ, MAP_PRIVATE, logfd, 0);
1363         logdata = log_mapped;
1364         close(logfd);
1365
1366         lastrec = NULL;
1367         rec = logend = logdata + st.st_size;
1368         while (logdata < rec) {
1369                 reccnt++;
1370                 if (logdata < rec && *(rec-1) == '\n')
1371                         rec--;
1372                 lastgt = NULL;
1373                 while (logdata < rec && *(rec-1) != '\n') {
1374                         rec--;
1375                         if (*rec == '>')
1376                                 lastgt = rec;
1377                 }
1378                 if (!lastgt)
1379                         die("Log %s is corrupt.", logfile);
1380                 date = strtoul(lastgt + 1, &tz_c, 10);
1381                 if (date <= at_time || cnt == 0) {
1382                         tz = strtoul(tz_c, NULL, 10);
1383                         if (msg)
1384                                 *msg = ref_msg(rec, logend);
1385                         if (cutoff_time)
1386                                 *cutoff_time = date;
1387                         if (cutoff_tz)
1388                                 *cutoff_tz = tz;
1389                         if (cutoff_cnt)
1390                                 *cutoff_cnt = reccnt - 1;
1391                         if (lastrec) {
1392                                 if (get_sha1_hex(lastrec, logged_sha1))
1393                                         die("Log %s is corrupt.", logfile);
1394                                 if (get_sha1_hex(rec + 41, sha1))
1395                                         die("Log %s is corrupt.", logfile);
1396                                 if (hashcmp(logged_sha1, sha1)) {
1397                                         fprintf(stderr,
1398                                                 "warning: Log %s has gap after %s.\n",
1399                                                 logfile, show_date(date, tz, DATE_RFC2822));
1400                                 }
1401                         }
1402                         else if (date == at_time) {
1403                                 if (get_sha1_hex(rec + 41, sha1))
1404                                         die("Log %s is corrupt.", logfile);
1405                         }
1406                         else {
1407                                 if (get_sha1_hex(rec + 41, logged_sha1))
1408                                         die("Log %s is corrupt.", logfile);
1409                                 if (hashcmp(logged_sha1, sha1)) {
1410                                         fprintf(stderr,
1411                                                 "warning: Log %s unexpectedly ended on %s.\n",
1412                                                 logfile, show_date(date, tz, DATE_RFC2822));
1413                                 }
1414                         }
1415                         munmap(log_mapped, mapsz);
1416                         return 0;
1417                 }
1418                 lastrec = rec;
1419                 if (cnt > 0)
1420                         cnt--;
1421         }
1422
1423         rec = logdata;
1424         while (rec < logend && *rec != '>' && *rec != '\n')
1425                 rec++;
1426         if (rec == logend || *rec == '\n')
1427                 die("Log %s is corrupt.", logfile);
1428         date = strtoul(rec + 1, &tz_c, 10);
1429         tz = strtoul(tz_c, NULL, 10);
1430         if (get_sha1_hex(logdata, sha1))
1431                 die("Log %s is corrupt.", logfile);
1432         if (is_null_sha1(sha1)) {
1433                 if (get_sha1_hex(logdata + 41, sha1))
1434                         die("Log %s is corrupt.", logfile);
1435         }
1436         if (msg)
1437                 *msg = ref_msg(logdata, logend);
1438         munmap(log_mapped, mapsz);
1439
1440         if (cutoff_time)
1441                 *cutoff_time = date;
1442         if (cutoff_tz)
1443                 *cutoff_tz = tz;
1444         if (cutoff_cnt)
1445                 *cutoff_cnt = reccnt;
1446         return 1;
1447 }
1448
1449 int for_each_reflog_ent(const char *ref, each_reflog_ent_fn fn, void *cb_data)
1450 {
1451         const char *logfile;
1452         FILE *logfp;
1453         char buf[1024];
1454         int ret = 0;
1455
1456         logfile = git_path("logs/%s", ref);
1457         logfp = fopen(logfile, "r");
1458         if (!logfp)
1459                 return -1;
1460         while (fgets(buf, sizeof(buf), logfp)) {
1461                 unsigned char osha1[20], nsha1[20];
1462                 char *email_end, *message;
1463                 unsigned long timestamp;
1464                 int len, tz;
1465
1466                 /* old SP new SP name <email> SP time TAB msg LF */
1467                 len = strlen(buf);
1468                 if (len < 83 || buf[len-1] != '\n' ||
1469                     get_sha1_hex(buf, osha1) || buf[40] != ' ' ||
1470                     get_sha1_hex(buf + 41, nsha1) || buf[81] != ' ' ||
1471                     !(email_end = strchr(buf + 82, '>')) ||
1472                     email_end[1] != ' ' ||
1473                     !(timestamp = strtoul(email_end + 2, &message, 10)) ||
1474                     !message || message[0] != ' ' ||
1475                     (message[1] != '+' && message[1] != '-') ||
1476                     !isdigit(message[2]) || !isdigit(message[3]) ||
1477                     !isdigit(message[4]) || !isdigit(message[5]))
1478                         continue; /* corrupt? */
1479                 email_end[1] = '\0';
1480                 tz = strtol(message + 1, NULL, 10);
1481                 if (message[6] != '\t')
1482                         message += 6;
1483                 else
1484                         message += 7;
1485                 ret = fn(osha1, nsha1, buf+82, timestamp, tz, message, cb_data);
1486                 if (ret)
1487                         break;
1488         }
1489         fclose(logfp);
1490         return ret;
1491 }
1492
1493 static int do_for_each_reflog(const char *base, each_ref_fn fn, void *cb_data)
1494 {
1495         DIR *dir = opendir(git_path("logs/%s", base));
1496         int retval = 0;
1497
1498         if (dir) {
1499                 struct dirent *de;
1500                 int baselen = strlen(base);
1501                 char *log = xmalloc(baselen + 257);
1502
1503                 memcpy(log, base, baselen);
1504                 if (baselen && base[baselen-1] != '/')
1505                         log[baselen++] = '/';
1506
1507                 while ((de = readdir(dir)) != NULL) {
1508                         struct stat st;
1509                         int namelen;
1510
1511                         if (de->d_name[0] == '.')
1512                                 continue;
1513                         namelen = strlen(de->d_name);
1514                         if (namelen > 255)
1515                                 continue;
1516                         if (has_extension(de->d_name, ".lock"))
1517                                 continue;
1518                         memcpy(log + baselen, de->d_name, namelen+1);
1519                         if (stat(git_path("logs/%s", log), &st) < 0)
1520                                 continue;
1521                         if (S_ISDIR(st.st_mode)) {
1522                                 retval = do_for_each_reflog(log, fn, cb_data);
1523                         } else {
1524                                 unsigned char sha1[20];
1525                                 if (!resolve_ref(log, sha1, 0, NULL))
1526                                         retval = error("bad ref for %s", log);
1527                                 else
1528                                         retval = fn(log, sha1, 0, cb_data);
1529                         }
1530                         if (retval)
1531                                 break;
1532                 }
1533                 free(log);
1534                 closedir(dir);
1535         }
1536         else if (*base)
1537                 return errno;
1538         return retval;
1539 }
1540
1541 int for_each_reflog(each_ref_fn fn, void *cb_data)
1542 {
1543         return do_for_each_reflog("", fn, cb_data);
1544 }
1545
1546 int update_ref(const char *action, const char *refname,
1547                 const unsigned char *sha1, const unsigned char *oldval,
1548                 int flags, enum action_on_err onerr)
1549 {
1550         static struct ref_lock *lock;
1551         lock = lock_any_ref_for_update(refname, oldval, flags);
1552         if (!lock) {
1553                 const char *str = "Cannot lock the ref '%s'.";
1554                 switch (onerr) {
1555                 case MSG_ON_ERR: error(str, refname); break;
1556                 case DIE_ON_ERR: die(str, refname); break;
1557                 case QUIET_ON_ERR: break;
1558                 }
1559                 return 1;
1560         }
1561         if (write_ref_sha1(lock, sha1, action) < 0) {
1562                 const char *str = "Cannot update the ref '%s'.";
1563                 switch (onerr) {
1564                 case MSG_ON_ERR: error(str, refname); break;
1565                 case DIE_ON_ERR: die(str, refname); break;
1566                 case QUIET_ON_ERR: break;
1567                 }
1568                 return 1;
1569         }
1570         return 0;
1571 }
1572
1573 struct ref *find_ref_by_name(struct ref *list, const char *name)
1574 {
1575         for ( ; list; list = list->next)
1576                 if (!strcmp(list->name, name))
1577                         return list;
1578         return NULL;
1579 }