refs.c

   1 #include "cache.h"
   2 #include "refs.h"
   3 #include "object.h"
   4 #include "tag.h"
   5 #include "dir.h"
   6
   7 /* ISSYMREF=01 and ISPACKED=02 are public interfaces */
   8 #define REF_KNOWS_PEELED 04
   9
  10 struct ref_list {
  11         struct ref_list *next;
  12         unsigned char flag; /* ISSYMREF? ISPACKED? */
  13         unsigned char sha1[20];
  14         unsigned char peeled[20];
  15         char name[FLEX_ARRAY];
  16 };
  17
  18 static const char *parse_ref_line(char *line, unsigned char *sha1)
  19 {
  20         /*
  21          * 42: the answer to everything.
  22          *
  23          * In this case, it happens to be the answer to
  24          *  40 (length of sha1 hex representation)
  25          *  +1 (space in between hex and name)
  26          *  +1 (newline at the end of the line)
  27          */
  28         int len = strlen(line) - 42;
  29
  30         if (len <= 0)
  31                 return NULL;
  32         if (get_sha1_hex(line, sha1) < 0)
  33                 return NULL;
  34         if (!isspace(line[40]))
  35                 return NULL;
  36         line += 41;
  37         if (isspace(*line))
  38                 return NULL;
  39         if (line[len] != '\n')
  40                 return NULL;
  41         line[len] = 0;
  42
  43         return line;
  44 }
  45
  46 static struct ref_list *add_ref(const char *name, const unsigned char *sha1,
  47                                 int flag, struct ref_list *list,
  48                                 struct ref_list **new_entry)
  49 {
  50         int len;
  51         struct ref_list *entry;
  52
  53         /* Allocate it and add it in.. */
  54         len = strlen(name) + 1;
  55         entry = xmalloc(sizeof(struct ref_list) + len);
  56         hashcpy(entry->sha1, sha1);
  57         hashclr(entry->peeled);
  58         memcpy(entry->name, name, len);
  59         entry->flag = flag;
  60         entry->next = list;
  61         if (new_entry)
  62                 *new_entry = entry;
  63         return entry;
  64 }
  65
  66 /* merge sort the ref list */
  67 static struct ref_list *sort_ref_list(struct ref_list *list)
  68 {
  69         int psize, qsize, last_merge_count, cmp;
  70         struct ref_list *p, *q, *l, *e;
  71         struct ref_list *new_list = list;
  72         int k = 1;
  73         int merge_count = 0;
  74
  75         if (!list)
  76                 return list;
  77
  78         do {
  79                 last_merge_count = merge_count;
  80                 merge_count = 0;
  81
  82                 psize = 0;
  83
  84                 p = new_list;
  85                 q = new_list;
  86                 new_list = NULL;
  87                 l = NULL;
  88
  89                 while (p) {
  90                         merge_count++;
  91
  92                         while (psize < k && q->next) {
  93                                 q = q->next;
  94                                 psize++;
  95                         }
  96                         qsize = k;
  97
  98                         while ((psize > 0) || (qsize > 0 && q)) {
  99                                 if (qsize == 0 || !q) {
 100                                         e = p;
 101                                         p = p->next;
 102                                         psize--;
 103                                 } else if (psize == 0) {
 104                                         e = q;
 105                                         q = q->next;
 106                                         qsize--;
 107                                 } else {
 108                                         cmp = strcmp(q->name, p->name);
 109                                         if (cmp < 0) {
 110                                                 e = q;
 111                                                 q = q->next;
 112                                                 qsize--;
 113                                         } else if (cmp > 0) {
 114                                                 e = p;
 115                                                 p = p->next;
 116                                                 psize--;
 117                                         } else {
 118                                                 if (hashcmp(q->sha1, p->sha1))
 119                                                         die("Duplicated ref, and SHA1s don't match: %s",
 120                                                             q->name);
 121                                                 warning("Duplicated ref: %s", q->name);
 122                                                 e = q;
 123                                                 q = q->next;
 124                                                 qsize--;
 125                                                 free(e);
 126                                                 e = p;
 127                                                 p = p->next;
 128                                                 psize--;
 129                                         }
 130                                 }
 131
 132                                 e->next = NULL;
 133
 134                                 if (l)
 135                                         l->next = e;
 136                                 if (!new_list)
 137                                         new_list = e;
 138                                 l = e;
 139                         }
 140
 141                         p = q;
 142                 };
 143
 144                 k = k * 2;
 145         } while ((last_merge_count != merge_count) || (last_merge_count != 1));
 146
 147         return new_list;
 148 }
 149
 150 /*
 151  * Future: need to be in "struct repository"
 152  * when doing a full libification.
 153  */
 154 static struct cached_refs {
 155         char did_loose;
 156         char did_packed;
 157         struct ref_list *loose;
 158         struct ref_list *packed;
 159 } cached_refs;
 160 static struct ref_list *current_ref;
 161
 162 static void free_ref_list(struct ref_list *list)
 163 {
 164         struct ref_list *next;
 165         for ( ; list; list = next) {
 166                 next = list->next;
 167                 free(list);
 168         }
 169 }
 170
 171 static void invalidate_cached_refs(void)
 172 {
 173         struct cached_refs *ca = &cached_refs;
 174
 175         if (ca->did_loose && ca->loose)
 176                 free_ref_list(ca->loose);
 177         if (ca->did_packed && ca->packed)
 178                 free_ref_list(ca->packed);
 179         ca->loose = ca->packed = NULL;
 180         ca->did_loose = ca->did_packed = 0;
 181 }
 182
 183 static void read_packed_refs(FILE *f, struct cached_refs *cached_refs)
 184 {
 185         struct ref_list *list = NULL;
 186         struct ref_list *last = NULL;
 187         char refline[PATH_MAX];
 188         int flag = REF_ISPACKED;
 189
 190         while (fgets(refline, sizeof(refline), f)) {
 191                 unsigned char sha1[20];
 192                 const char *name;
 193                 static const char header[] = "# pack-refs with:";
 194
 195                 if (!strncmp(refline, header, sizeof(header)-1)) {
 196                         const char *traits = refline + sizeof(header) - 1;
 197                         if (strstr(traits, " peeled "))
 198                                 flag |= REF_KNOWS_PEELED;
 199                         /* perhaps other traits later as well */
 200                         continue;
 201                 }
 202
 203                 name = parse_ref_line(refline, sha1);
 204                 if (name) {
 205                         list = add_ref(name, sha1, flag, list, &last);
 206                         continue;
 207                 }
 208                 if (last &&
 209                     refline[0] == '^' &&
 210                     strlen(refline) == 42 &&
 211                     refline[41] == '\n' &&
 212                     !get_sha1_hex(refline + 1, sha1))
 213                         hashcpy(last->peeled, sha1);
 214         }
 215         cached_refs->packed = sort_ref_list(list);
 216 }
 217
 218 static struct ref_list *get_packed_refs(void)
 219 {
 220         if (!cached_refs.did_packed) {
 221                 FILE *f = fopen(git_path("packed-refs"), "r");
 222                 cached_refs.packed = NULL;
 223                 if (f) {
 224                         read_packed_refs(f, &cached_refs);
 225                         fclose(f);
 226                 }
 227                 cached_refs.did_packed = 1;
 228         }
 229         return cached_refs.packed;
 230 }
 231
 232 static struct ref_list *get_ref_dir(const char *base, struct ref_list *list)
 233 {
 234         DIR *dir = opendir(git_path("%s", base));
 235
 236         if (dir) {
 237                 struct dirent *de;
 238                 int baselen = strlen(base);
 239                 char *ref = xmalloc(baselen + 257);
 240
 241                 memcpy(ref, base, baselen);
 242                 if (baselen && base[baselen-1] != '/')
 243                         ref[baselen++] = '/';
 244
 245                 while ((de = readdir(dir)) != NULL) {
 246                         unsigned char sha1[20];
 247                         struct stat st;
 248                         int flag;
 249                         int namelen;
 250
 251                         if (de->d_name[0] == '.')
 252                                 continue;
 253                         namelen = strlen(de->d_name);
 254                         if (namelen > 255)
 255                                 continue;
 256                         if (has_extension(de->d_name, ".lock"))
 257                                 continue;
 258                         memcpy(ref + baselen, de->d_name, namelen+1);
 259                         if (stat(git_path("%s", ref), &st) < 0)
 260                                 continue;
 261                         if (S_ISDIR(st.st_mode)) {
 262                                 list = get_ref_dir(ref, list);
 263                                 continue;
 264                         }
 265                         if (!resolve_ref(ref, sha1, 1, &flag)) {
 266                                 error("%s points nowhere!", ref);
 267                                 continue;
 268                         }
 269                         list = add_ref(ref, sha1, flag, list, NULL);
 270                 }
 271                 free(ref);
 272                 closedir(dir);
 273         }
 274         return sort_ref_list(list);
 275 }
 276
 277 static struct ref_list *get_loose_refs(void)
 278 {
 279         if (!cached_refs.did_loose) {
 280                 cached_refs.loose = get_ref_dir("refs", NULL);
 281                 cached_refs.did_loose = 1;
 282         }
 283         return cached_refs.loose;
 284 }
 285
 286 /* We allow "recursive" symbolic refs. Only within reason, though */
 287 #define MAXDEPTH 5
 288 #define MAXREFLEN (1024)
 289
 290 static int resolve_gitlink_packed_ref(char *name, int pathlen, const char *refname, unsigned char *result)
 291 {
 292         FILE *f;
 293         struct cached_refs refs;
 294         struct ref_list *ref;
 295         int retval;
 296
 297         strcpy(name + pathlen, "packed-refs");
 298         f = fopen(name, "r");
 299         if (!f)
 300                 return -1;
 301         read_packed_refs(f, &refs);
 302         fclose(f);
 303         ref = refs.packed;
 304         retval = -1;
 305         while (ref) {
 306                 if (!strcmp(ref->name, refname)) {
 307                         retval = 0;
 308                         memcpy(result, ref->sha1, 20);
 309                         break;
 310                 }
 311                 ref = ref->next;
 312         }
 313         free_ref_list(refs.packed);
 314         return retval;
 315 }
 316
 317 static int resolve_gitlink_ref_recursive(char *name, int pathlen, const char *refname, unsigned char *result, int recursion)
 318 {
 319         int fd, len = strlen(refname);
 320         char buffer[128], *p;
 321
 322         if (recursion > MAXDEPTH || len > MAXREFLEN)
 323                 return -1;
 324         memcpy(name + pathlen, refname, len+1);
 325         fd = open(name, O_RDONLY);
 326         if (fd < 0)
 327                 return resolve_gitlink_packed_ref(name, pathlen, refname, result);
 328
 329         len = read(fd, buffer, sizeof(buffer)-1);
 330         close(fd);
 331         if (len < 0)
 332                 return -1;
 333         while (len && isspace(buffer[len-1]))
 334                 len--;
 335         buffer[len] = 0;
 336
 337         /* Was it a detached head or an old-fashioned symlink? */
 338         if (!get_sha1_hex(buffer, result))
 339                 return 0;
 340
 341         /* Symref? */
 342         if (strncmp(buffer, "ref:", 4))
 343                 return -1;
 344         p = buffer + 4;
 345         while (isspace(*p))
 346                 p++;
 347
 348         return resolve_gitlink_ref_recursive(name, pathlen, p, result, recursion+1);
 349 }
 350
 351 int resolve_gitlink_ref(const char *path, const char *refname, unsigned char *result)
 352 {
 353         int len = strlen(path), retval;
 354         char *gitdir;
 355
 356         while (len && path[len-1] == '/')
 357                 len--;
 358         if (!len)
 359                 return -1;
 360         gitdir = xmalloc(len + MAXREFLEN + 8);
 361         memcpy(gitdir, path, len);
 362         memcpy(gitdir + len, "/.git/", 7);
 363
 364         retval = resolve_gitlink_ref_recursive(gitdir, len+6, refname, result, 0);
 365         free(gitdir);
 366         return retval;
 367 }
 368
 369 const char *resolve_ref(const char *ref, unsigned char *sha1, int reading, int *flag)
 370 {
 371         int depth = MAXDEPTH, len;
 372         char buffer[256];
 373         static char ref_buffer[256];
 374
 375         if (flag)
 376                 *flag = 0;
 377
 378         for (;;) {
 379                 const char *path = git_path("%s", ref);
 380                 struct stat st;
 381                 char *buf;
 382                 int fd;
 383
 384                 if (--depth < 0)
 385                         return NULL;
 386
 387                 /* Special case: non-existing file.
 388                  * Not having the refs/heads/new-branch is OK
 389                  * if we are writing into it, so is .git/HEAD
 390                  * that points at refs/heads/master still to be
 391                  * born.  It is NOT OK if we are resolving for
 392                  * reading.
 393                  */
 394                 if (lstat(path, &st) < 0) {
 395                         struct ref_list *list = get_packed_refs();
 396                         while (list) {
 397                                 if (!strcmp(ref, list->name)) {
 398                                         hashcpy(sha1, list->sha1);
 399                                         if (flag)
 400                                                 *flag |= REF_ISPACKED;
 401                                         return ref;
 402                                 }
 403                                 list = list->next;
 404                         }
 405                         if (reading || errno != ENOENT)
 406                                 return NULL;
 407                         hashclr(sha1);
 408                         return ref;
 409                 }
 410
 411                 /* Follow "normalized" - ie "refs/.." symlinks by hand */
 412                 if (S_ISLNK(st.st_mode)) {
 413                         len = readlink(path, buffer, sizeof(buffer)-1);
 414                         if (len >= 5 && !memcmp("refs/", buffer, 5)) {
 415                                 buffer[len] = 0;
 416                                 strcpy(ref_buffer, buffer);
 417                                 ref = ref_buffer;
 418                                 if (flag)
 419                                         *flag |= REF_ISSYMREF;
 420                                 continue;
 421                         }
 422                 }
 423
 424                 /* Is it a directory? */
 425                 if (S_ISDIR(st.st_mode)) {
 426                         errno = EISDIR;
 427                         return NULL;
 428                 }
 429
 430                 /*
 431                  * Anything else, just open it and try to use it as
 432                  * a ref
 433                  */
 434                 fd = open(path, O_RDONLY);
 435                 if (fd < 0)
 436                         return NULL;
 437                 len = read_in_full(fd, buffer, sizeof(buffer)-1);
 438                 close(fd);
 439
 440                 /*
 441                  * Is it a symbolic ref?
 442                  */
 443                 if (len < 4 || memcmp("ref:", buffer, 4))
 444                         break;
 445                 buf = buffer + 4;
 446                 len -= 4;
 447                 while (len && isspace(*buf))
 448                         buf++, len--;
 449                 while (len && isspace(buf[len-1]))
 450                         len--;
 451                 buf[len] = 0;
 452                 memcpy(ref_buffer, buf, len + 1);
 453                 ref = ref_buffer;
 454                 if (flag)
 455                         *flag |= REF_ISSYMREF;
 456         }
 457         if (len < 40 || get_sha1_hex(buffer, sha1))
 458                 return NULL;
 459         return ref;
 460 }
 461
 462 int read_ref(const char *ref, unsigned char *sha1)
 463 {
 464         if (resolve_ref(ref, sha1, 1, NULL))
 465                 return 0;
 466         return -1;
 467 }
 468
 469 static int do_one_ref(const char *base, each_ref_fn fn, int trim,
 470                       void *cb_data, struct ref_list *entry)
 471 {
 472         if (strncmp(base, entry->name, trim))
 473                 return 0;
 474         if (is_null_sha1(entry->sha1))
 475                 return 0;
 476         if (!has_sha1_file(entry->sha1)) {
 477                 error("%s does not point to a valid object!", entry->name);
 478                 return 0;
 479         }
 480         current_ref = entry;
 481         return fn(entry->name + trim, entry->sha1, entry->flag, cb_data);
 482 }
 483
 484 int peel_ref(const char *ref, unsigned char *sha1)
 485 {
 486         int flag;
 487         unsigned char base[20];
 488         struct object *o;
 489
 490         if (current_ref && (current_ref->name == ref
 491                 || !strcmp(current_ref->name, ref))) {
 492                 if (current_ref->flag & REF_KNOWS_PEELED) {
 493                         hashcpy(sha1, current_ref->peeled);
 494                         return 0;
 495                 }
 496                 hashcpy(base, current_ref->sha1);
 497                 goto fallback;
 498         }
 499
 500         if (!resolve_ref(ref, base, 1, &flag))
 501                 return -1;
 502
 503         if ((flag & REF_ISPACKED)) {
 504                 struct ref_list *list = get_packed_refs();
 505
 506                 while (list) {
 507                         if (!strcmp(list->name, ref)) {
 508                                 if (list->flag & REF_KNOWS_PEELED) {
 509                                         hashcpy(sha1, list->peeled);
 510                                         return 0;
 511                                 }
 512                                 /* older pack-refs did not leave peeled ones */
 513                                 break;
 514                         }
 515                         list = list->next;
 516                 }
 517         }
 518
 519 fallback:
 520         o = parse_object(base);
 521         if (o && o->type == OBJ_TAG) {
 522                 o = deref_tag(o, ref, 0);
 523                 if (o) {
 524                         hashcpy(sha1, o->sha1);
 525                         return 0;
 526                 }
 527         }
 528         return -1;
 529 }
 530
 531 static int do_for_each_ref(const char *base, each_ref_fn fn, int trim,
 532                            void *cb_data)
 533 {
 534         int retval = 0;
 535         struct ref_list *packed = get_packed_refs();
 536         struct ref_list *loose = get_loose_refs();
 537
 538         while (packed && loose) {
 539                 struct ref_list *entry;
 540                 int cmp = strcmp(packed->name, loose->name);
 541                 if (!cmp) {
 542                         packed = packed->next;
 543                         continue;
 544                 }
 545                 if (cmp > 0) {
 546                         entry = loose;
 547                         loose = loose->next;
 548                 } else {
 549                         entry = packed;
 550                         packed = packed->next;
 551                 }
 552                 retval = do_one_ref(base, fn, trim, cb_data, entry);
 553                 if (retval)
 554                         goto end_each;
 555         }
 556
 557         for (packed = packed ? packed : loose; packed; packed = packed->next) {
 558                 retval = do_one_ref(base, fn, trim, cb_data, packed);
 559                 if (retval)
 560                         goto end_each;
 561         }
 562
 563 end_each:
 564         current_ref = NULL;
 565         return retval;
 566 }
 567
 568 int head_ref(each_ref_fn fn, void *cb_data)
 569 {
 570         unsigned char sha1[20];
 571         int flag;
 572
 573         if (resolve_ref("HEAD", sha1, 1, &flag))
 574                 return fn("HEAD", sha1, flag, cb_data);
 575         return 0;
 576 }
 577
 578 int for_each_ref(each_ref_fn fn, void *cb_data)
 579 {
 580         return do_for_each_ref("refs/", fn, 0, cb_data);
 581 }
 582
 583 int for_each_tag_ref(each_ref_fn fn, void *cb_data)
 584 {
 585         return do_for_each_ref("refs/tags/", fn, 10, cb_data);
 586 }
 587
 588 int for_each_branch_ref(each_ref_fn fn, void *cb_data)
 589 {
 590         return do_for_each_ref("refs/heads/", fn, 11, cb_data);
 591 }
 592
 593 int for_each_remote_ref(each_ref_fn fn, void *cb_data)
 594 {
 595         return do_for_each_ref("refs/remotes/", fn, 13, cb_data);
 596 }
 597
 598 /*
 599  * Make sure "ref" is something reasonable to have under ".git/refs/";
 600  * We do not like it if:
 601  *
 602  * - any path component of it begins with ".", or
 603  * - it has double dots "..", or
 604  * - it has ASCII control character, "~", "^", ":" or SP, anywhere, or
 605  * - it ends with a "/".
 606  */
 607
 608 static inline int bad_ref_char(int ch)
 609 {
 610         if (((unsigned) ch) <= ' ' ||
 611             ch == '~' || ch == '^' || ch == ':')
 612                 return 1;
 613         /* 2.13 Pattern Matching Notation */
 614         if (ch == '?' || ch == '[') /* Unsupported */
 615                 return 1;
 616         if (ch == '*') /* Supported at the end */
 617                 return 2;
 618         return 0;
 619 }
 620
 621 int check_ref_format(const char *ref)
 622 {
 623         int ch, level, bad_type;
 624         const char *cp = ref;
 625
 626         level = 0;
 627         while (1) {
 628                 while ((ch = *cp++) == '/')
 629                         ; /* tolerate duplicated slashes */
 630                 if (!ch)
 631                         /* should not end with slashes */
 632                         return CHECK_REF_FORMAT_ERROR;
 633
 634                 /* we are at the beginning of the path component */
 635                 if (ch == '.')
 636                         return CHECK_REF_FORMAT_ERROR;
 637                 bad_type = bad_ref_char(ch);
 638                 if (bad_type) {
 639                         return (bad_type == 2 && !*cp)
 640                                 ? CHECK_REF_FORMAT_WILDCARD
 641                                 : CHECK_REF_FORMAT_ERROR;
 642                 }
 643
 644                 /* scan the rest of the path component */
 645                 while ((ch = *cp++) != 0) {
 646                         bad_type = bad_ref_char(ch);
 647                         if (bad_type) {
 648                                 return (bad_type == 2 && !*cp)
 649                                         ? CHECK_REF_FORMAT_WILDCARD
 650                                         : CHECK_REF_FORMAT_ERROR;
 651                         }
 652                         if (ch == '/')
 653                                 break;
 654                         if (ch == '.' && *cp == '.')
 655                                 return CHECK_REF_FORMAT_ERROR;
 656                 }
 657                 level++;
 658                 if (!ch) {
 659                         if (level < 2)
 660                                 return CHECK_REF_FORMAT_ONELEVEL;
 661                         return CHECK_REF_FORMAT_OK;
 662                 }
 663         }
 664 }
 665
 666 const char *ref_rev_parse_rules[] = {
 667         "%.*s",
 668         "refs/%.*s",
 669         "refs/tags/%.*s",
 670         "refs/heads/%.*s",
 671         "refs/remotes/%.*s",
 672         "refs/remotes/%.*s/HEAD",
 673         NULL
 674 };
 675
 676 const char *ref_fetch_rules[] = {
 677         "%.*s",
 678         "refs/%.*s",
 679         "refs/heads/%.*s",
 680         NULL
 681 };
 682
 683 int refname_match(const char *abbrev_name, const char *full_name, const char **rules)
 684 {
 685         const char **p;
 686         const int abbrev_name_len = strlen(abbrev_name);
 687
 688         for (p = rules; *p; p++) {
 689                 if (!strcmp(full_name, mkpath(*p, abbrev_name_len, abbrev_name))) {
 690                         return 1;
 691                 }
 692         }
 693
 694         return 0;
 695 }
 696
 697 static struct ref_lock *verify_lock(struct ref_lock *lock,
 698         const unsigned char *old_sha1, int mustexist)
 699 {
 700         if (!resolve_ref(lock->ref_name, lock->old_sha1, mustexist, NULL)) {
 701                 error("Can't verify ref %s", lock->ref_name);
 702                 unlock_ref(lock);
 703                 return NULL;
 704         }
 705         if (hashcmp(lock->old_sha1, old_sha1)) {
 706                 error("Ref %s is at %s but expected %s", lock->ref_name,
 707                         sha1_to_hex(lock->old_sha1), sha1_to_hex(old_sha1));
 708                 unlock_ref(lock);
 709                 return NULL;
 710         }
 711         return lock;
 712 }
 713
 714 static int remove_empty_directories(const char *file)
 715 {
 716         /* we want to create a file but there is a directory there;
 717          * if that is an empty directory (or a directory that contains
 718          * only empty directories), remove them.
 719          */
 720         struct strbuf path;
 721         int result;
 722
 723         strbuf_init(&path, 20);
 724         strbuf_addstr(&path, file);
 725
 726         result = remove_dir_recursively(&path, 1);
 727
 728         strbuf_release(&path);
 729
 730         return result;
 731 }
 732
 733 static int is_refname_available(const char *ref, const char *oldref,
 734                                 struct ref_list *list, int quiet)
 735 {
 736         int namlen = strlen(ref); /* e.g. 'foo/bar' */
 737         while (list) {
 738                 /* list->name could be 'foo' or 'foo/bar/baz' */
 739                 if (!oldref || strcmp(oldref, list->name)) {
 740                         int len = strlen(list->name);
 741                         int cmplen = (namlen < len) ? namlen : len;
 742                         const char *lead = (namlen < len) ? list->name : ref;
 743                         if (!strncmp(ref, list->name, cmplen) &&
 744                             lead[cmplen] == '/') {
 745                                 if (!quiet)
 746                                         error("'%s' exists; cannot create '%s'",
 747                                               list->name, ref);
 748                                 return 0;
 749                         }
 750                 }
 751                 list = list->next;
 752         }
 753         return 1;
 754 }
 755
 756 static struct ref_lock *lock_ref_sha1_basic(const char *ref, const unsigned char *old_sha1, int flags, int *type_p)
 757 {
 758         char *ref_file;
 759         const char *orig_ref = ref;
 760         struct ref_lock *lock;
 761         struct stat st;
 762         int last_errno = 0;
 763         int type;
 764         int mustexist = (old_sha1 && !is_null_sha1(old_sha1));
 765
 766         lock = xcalloc(1, sizeof(struct ref_lock));
 767         lock->lock_fd = -1;
 768
 769         ref = resolve_ref(ref, lock->old_sha1, mustexist, &type);
 770         if (!ref && errno == EISDIR) {
 771                 /* we are trying to lock foo but we used to
 772                  * have foo/bar which now does not exist;
 773                  * it is normal for the empty directory 'foo'
 774                  * to remain.
 775                  */
 776                 ref_file = git_path("%s", orig_ref);
 777                 if (remove_empty_directories(ref_file)) {
 778                         last_errno = errno;
 779                         error("there are still refs under '%s'", orig_ref);
 780                         goto error_return;
 781                 }
 782                 ref = resolve_ref(orig_ref, lock->old_sha1, mustexist, &type);
 783         }
 784         if (type_p)
 785             *type_p = type;
 786         if (!ref) {
 787                 last_errno = errno;
 788                 error("unable to resolve reference %s: %s",
 789                         orig_ref, strerror(errno));
 790                 goto error_return;
 791         }
 792         /* When the ref did not exist and we are creating it,
 793          * make sure there is no existing ref that is packed
 794          * whose name begins with our refname, nor a ref whose
 795          * name is a proper prefix of our refname.
 796          */
 797         if (is_null_sha1(lock->old_sha1) &&
 798             !is_refname_available(ref, NULL, get_packed_refs(), 0))
 799                 goto error_return;
 800
 801         lock->lk = xcalloc(1, sizeof(struct lock_file));
 802
 803         if (flags & REF_NODEREF)
 804                 ref = orig_ref;
 805         lock->ref_name = xstrdup(ref);
 806         lock->orig_ref_name = xstrdup(orig_ref);
 807         ref_file = git_path("%s", ref);
 808         if (lstat(ref_file, &st) && errno == ENOENT)
 809                 lock->force_write = 1;
 810         if ((flags & REF_NODEREF) && (type & REF_ISSYMREF))
 811                 lock->force_write = 1;
 812
 813         if (safe_create_leading_directories(ref_file)) {
 814                 last_errno = errno;
 815                 error("unable to create directory for %s", ref_file);
 816                 goto error_return;
 817         }
 818         lock->lock_fd = hold_lock_file_for_update(lock->lk, ref_file, 1);
 819
 820         return old_sha1 ? verify_lock(lock, old_sha1, mustexist) : lock;
 821
 822  error_return:
 823         unlock_ref(lock);
 824         errno = last_errno;
 825         return NULL;
 826 }
 827
 828 struct ref_lock *lock_ref_sha1(const char *ref, const unsigned char *old_sha1)
 829 {
 830         char refpath[PATH_MAX];
 831         if (check_ref_format(ref))
 832                 return NULL;
 833         strcpy(refpath, mkpath("refs/%s", ref));
 834         return lock_ref_sha1_basic(refpath, old_sha1, 0, NULL);
 835 }
 836
 837 struct ref_lock *lock_any_ref_for_update(const char *ref, const unsigned char *old_sha1, int flags)
 838 {
 839         switch (check_ref_format(ref)) {
 840         default:
 841                 return NULL;
 842         case 0:
 843         case CHECK_REF_FORMAT_ONELEVEL:
 844                 return lock_ref_sha1_basic(ref, old_sha1, flags, NULL);
 845         }
 846 }
 847
 848 static struct lock_file packlock;
 849
 850 static int repack_without_ref(const char *refname)
 851 {
 852         struct ref_list *list, *packed_ref_list;
 853         int fd;
 854         int found = 0;
 855
 856         packed_ref_list = get_packed_refs();
 857         for (list = packed_ref_list; list; list = list->next) {
 858                 if (!strcmp(refname, list->name)) {
 859                         found = 1;
 860                         break;
 861                 }
 862         }
 863         if (!found)
 864                 return 0;
 865         fd = hold_lock_file_for_update(&packlock, git_path("packed-refs"), 0);
 866         if (fd < 0)
 867                 return error("cannot delete '%s' from packed refs", refname);
 868
 869         for (list = packed_ref_list; list; list = list->next) {
 870                 char line[PATH_MAX + 100];
 871                 int len;
 872
 873                 if (!strcmp(refname, list->name))
 874                         continue;
 875                 len = snprintf(line, sizeof(line), "%s %s\n",
 876                                sha1_to_hex(list->sha1), list->name);
 877                 /* this should not happen but just being defensive */
 878                 if (len > sizeof(line))
 879                         die("too long a refname '%s'", list->name);
 880                 write_or_die(fd, line, len);
 881         }
 882         return commit_lock_file(&packlock);
 883 }
 884
 885 int delete_ref(const char *refname, const unsigned char *sha1)
 886 {
 887         struct ref_lock *lock;
 888         int err, i, ret = 0, flag = 0;
 889
 890         lock = lock_ref_sha1_basic(refname, sha1, 0, &flag);
 891         if (!lock)
 892                 return 1;
 893         if (!(flag & REF_ISPACKED)) {
 894                 /* loose */
 895                 i = strlen(lock->lk->filename) - 5; /* .lock */
 896                 lock->lk->filename[i] = 0;
 897                 err = unlink(lock->lk->filename);
 898                 if (err) {
 899                         ret = 1;
 900                         error("unlink(%s) failed: %s",
 901                               lock->lk->filename, strerror(errno));
 902                 }
 903                 lock->lk->filename[i] = '.';
 904         }
 905         /* removing the loose one could have resurrected an earlier
 906          * packed one.  Also, if it was not loose we need to repack
 907          * without it.
 908          */
 909         ret |= repack_without_ref(refname);
 910
 911         err = unlink(git_path("logs/%s", lock->ref_name));
 912         if (err && errno != ENOENT)
 913                 fprintf(stderr, "warning: unlink(%s) failed: %s",
 914                         git_path("logs/%s", lock->ref_name), strerror(errno));
 915         invalidate_cached_refs();
 916         unlock_ref(lock);
 917         return ret;
 918 }
 919
 920 int rename_ref(const char *oldref, const char *newref, const char *logmsg)
 921 {
 922         static const char renamed_ref[] = "RENAMED-REF";
 923         unsigned char sha1[20], orig_sha1[20];
 924         int flag = 0, logmoved = 0;
 925         struct ref_lock *lock;
 926         struct stat loginfo;
 927         int log = !lstat(git_path("logs/%s", oldref), &loginfo);
 928
 929         if (S_ISLNK(loginfo.st_mode))
 930                 return error("reflog for %s is a symlink", oldref);
 931
 932         if (!resolve_ref(oldref, orig_sha1, 1, &flag))
 933                 return error("refname %s not found", oldref);
 934
 935         if (!is_refname_available(newref, oldref, get_packed_refs(), 0))
 936                 return 1;
 937
 938         if (!is_refname_available(newref, oldref, get_loose_refs(), 0))
 939                 return 1;
 940
 941         lock = lock_ref_sha1_basic(renamed_ref, NULL, 0, NULL);
 942         if (!lock)
 943                 return error("unable to lock %s", renamed_ref);
 944         lock->force_write = 1;
 945         if (write_ref_sha1(lock, orig_sha1, logmsg))
 946                 return error("unable to save current sha1 in %s", renamed_ref);
 947
 948         if (log && rename(git_path("logs/%s", oldref), git_path("tmp-renamed-log")))
 949                 return error("unable to move logfile logs/%s to tmp-renamed-log: %s",
 950                         oldref, strerror(errno));
 951
 952         if (delete_ref(oldref, orig_sha1)) {
 953                 error("unable to delete old %s", oldref);
 954                 goto rollback;
 955         }
 956
 957         if (resolve_ref(newref, sha1, 1, &flag) && delete_ref(newref, sha1)) {
 958                 if (errno==EISDIR) {
 959                         if (remove_empty_directories(git_path("%s", newref))) {
 960                                 error("Directory not empty: %s", newref);
 961                                 goto rollback;
 962                         }
 963                 } else {
 964                         error("unable to delete existing %s", newref);
 965                         goto rollback;
 966                 }
 967         }
 968
 969         if (log && safe_create_leading_directories(git_path("logs/%s", newref))) {
 970                 error("unable to create directory for %s", newref);
 971                 goto rollback;
 972         }
 973
 974  retry:
 975         if (log && rename(git_path("tmp-renamed-log"), git_path("logs/%s", newref))) {
 976                 if (errno==EISDIR || errno==ENOTDIR) {
 977                         /*
 978                          * rename(a, b) when b is an existing
 979                          * directory ought to result in ISDIR, but
 980                          * Solaris 5.8 gives ENOTDIR.  Sheesh.
 981                          */
 982                         if (remove_empty_directories(git_path("logs/%s", newref))) {
 983                                 error("Directory not empty: logs/%s", newref);
 984                                 goto rollback;
 985                         }
 986                         goto retry;
 987                 } else {
 988                         error("unable to move logfile tmp-renamed-log to logs/%s: %s",
 989                                 newref, strerror(errno));
 990                         goto rollback;
 991                 }
 992         }
 993         logmoved = log;
 994
 995         lock = lock_ref_sha1_basic(newref, NULL, 0, NULL);
 996         if (!lock) {
 997                 error("unable to lock %s for update", newref);
 998                 goto rollback;
 999         }
1000
1001         lock->force_write = 1;
1002         hashcpy(lock->old_sha1, orig_sha1);
1003         if (write_ref_sha1(lock, orig_sha1, logmsg)) {
1004                 error("unable to write current sha1 into %s", newref);
1005                 goto rollback;
1006         }
1007
1008         return 0;
1009
1010  rollback:
1011         lock = lock_ref_sha1_basic(oldref, NULL, 0, NULL);
1012         if (!lock) {
1013                 error("unable to lock %s for rollback", oldref);
1014                 goto rollbacklog;
1015         }
1016
1017         lock->force_write = 1;
1018         flag = log_all_ref_updates;
1019         log_all_ref_updates = 0;
1020         if (write_ref_sha1(lock, orig_sha1, NULL))
1021                 error("unable to write current sha1 into %s", oldref);
1022         log_all_ref_updates = flag;
1023
1024  rollbacklog:
1025         if (logmoved && rename(git_path("logs/%s", newref), git_path("logs/%s", oldref)))
1026                 error("unable to restore logfile %s from %s: %s",
1027                         oldref, newref, strerror(errno));
1028         if (!logmoved && log &&
1029             rename(git_path("tmp-renamed-log"), git_path("logs/%s", oldref)))
1030                 error("unable to restore logfile %s from tmp-renamed-log: %s",
1031                         oldref, strerror(errno));
1032
1033         return 1;
1034 }
1035
1036 int close_ref(struct ref_lock *lock)
1037 {
1038         if (close_lock_file(lock->lk))
1039                 return -1;
1040         lock->lock_fd = -1;
1041         return 0;
1042 }
1043
1044 int commit_ref(struct ref_lock *lock)
1045 {
1046         if (commit_lock_file(lock->lk))
1047                 return -1;
1048         lock->lock_fd = -1;
1049         return 0;
1050 }
1051
1052 void unlock_ref(struct ref_lock *lock)
1053 {
1054         /* Do not free lock->lk -- atexit() still looks at them */
1055         if (lock->lk)
1056                 rollback_lock_file(lock->lk);
1057         free(lock->ref_name);
1058         free(lock->orig_ref_name);
1059         free(lock);
1060 }
1061
1062 /*
1063  * copy the reflog message msg to buf, which has been allocated sufficiently
1064  * large, while cleaning up the whitespaces.  Especially, convert LF to space,
1065  * because reflog file is one line per entry.
1066  */
1067 static int copy_msg(char *buf, const char *msg)
1068 {
1069         char *cp = buf;
1070         char c;
1071         int wasspace = 1;
1072
1073         *cp++ = '\t';
1074         while ((c = *msg++)) {
1075                 if (wasspace && isspace(c))
1076                         continue;
1077                 wasspace = isspace(c);
1078                 if (wasspace)
1079                         c = ' ';
1080                 *cp++ = c;
1081         }
1082         while (buf < cp && isspace(cp[-1]))
1083                 cp--;
1084         *cp++ = '\n';
1085         return cp - buf;
1086 }
1087
1088 static int log_ref_write(const char *ref_name, const unsigned char *old_sha1,
1089                          const unsigned char *new_sha1, const char *msg)
1090 {
1091         int logfd, written, oflags = O_APPEND | O_WRONLY;
1092         unsigned maxlen, len;
1093         int msglen;
1094         char *log_file, *logrec;
1095         const char *committer;
1096
1097         if (log_all_ref_updates < 0)
1098                 log_all_ref_updates = !is_bare_repository();
1099
1100         log_file = git_path("logs/%s", ref_name);
1101
1102         if (log_all_ref_updates &&
1103             (!prefixcmp(ref_name, "refs/heads/") ||
1104              !prefixcmp(ref_name, "refs/remotes/") ||
1105              !strcmp(ref_name, "HEAD"))) {
1106                 if (safe_create_leading_directories(log_file) < 0)
1107                         return error("unable to create directory for %s",
1108                                      log_file);
1109                 oflags |= O_CREAT;
1110         }
1111
1112         logfd = open(log_file, oflags, 0666);
1113         if (logfd < 0) {
1114                 if (!(oflags & O_CREAT) && errno == ENOENT)
1115                         return 0;
1116
1117                 if ((oflags & O_CREAT) && errno == EISDIR) {
1118                         if (remove_empty_directories(log_file)) {
1119                                 return error("There are still logs under '%s'",
1120                                              log_file);
1121                         }
1122                         logfd = open(log_file, oflags, 0666);
1123                 }
1124
1125                 if (logfd < 0)
1126                         return error("Unable to append to %s: %s",
1127                                      log_file, strerror(errno));
1128         }
1129
1130         adjust_shared_perm(log_file);
1131
1132         msglen = msg ? strlen(msg) : 0;
1133         committer = git_committer_info(0);
1134         maxlen = strlen(committer) + msglen + 100;
1135         logrec = xmalloc(maxlen);
1136         len = sprintf(logrec, "%s %s %s\n",
1137                       sha1_to_hex(old_sha1),
1138                       sha1_to_hex(new_sha1),
1139                       committer);
1140         if (msglen)
1141                 len += copy_msg(logrec + len - 1, msg) - 1;
1142         written = len <= maxlen ? write_in_full(logfd, logrec, len) : -1;
1143         free(logrec);
1144         if (close(logfd) != 0 || written != len)
1145                 return error("Unable to append to %s", log_file);
1146         return 0;
1147 }
1148
1149 static int is_branch(const char *refname)
1150 {
1151         return !strcmp(refname, "HEAD") || !prefixcmp(refname, "refs/heads/");
1152 }
1153
1154 int write_ref_sha1(struct ref_lock *lock,
1155         const unsigned char *sha1, const char *logmsg)
1156 {
1157         static char term = '\n';
1158         struct object *o;
1159
1160         if (!lock)
1161                 return -1;
1162         if (!lock->force_write && !hashcmp(lock->old_sha1, sha1)) {
1163                 unlock_ref(lock);
1164                 return 0;
1165         }
1166         o = parse_object(sha1);
1167         if (!o) {
1168                 error("Trying to write ref %s with nonexistant object %s",
1169                         lock->ref_name, sha1_to_hex(sha1));
1170                 unlock_ref(lock);
1171                 return -1;
1172         }
1173         if (o->type != OBJ_COMMIT && is_branch(lock->ref_name)) {
1174                 error("Trying to write non-commit object %s to branch %s",
1175                         sha1_to_hex(sha1), lock->ref_name);
1176                 unlock_ref(lock);
1177                 return -1;
1178         }
1179         if (write_in_full(lock->lock_fd, sha1_to_hex(sha1), 40) != 40 ||
1180             write_in_full(lock->lock_fd, &term, 1) != 1
1181                 || close_ref(lock) < 0) {
1182                 error("Couldn't write %s", lock->lk->filename);
1183                 unlock_ref(lock);
1184                 return -1;
1185         }
1186         invalidate_cached_refs();
1187         if (log_ref_write(lock->ref_name, lock->old_sha1, sha1, logmsg) < 0 ||
1188             (strcmp(lock->ref_name, lock->orig_ref_name) &&
1189              log_ref_write(lock->orig_ref_name, lock->old_sha1, sha1, logmsg) < 0)) {
1190                 unlock_ref(lock);
1191                 return -1;
1192         }
1193         if (strcmp(lock->orig_ref_name, "HEAD") != 0) {
1194                 /*
1195                  * Special hack: If a branch is updated directly and HEAD
1196                  * points to it (may happen on the remote side of a push
1197                  * for example) then logically the HEAD reflog should be
1198                  * updated too.
1199                  * A generic solution implies reverse symref information,
1200                  * but finding all symrefs pointing to the given branch
1201                  * would be rather costly for this rare event (the direct
1202                  * update of a branch) to be worth it.  So let's cheat and
1203                  * check with HEAD only which should cover 99% of all usage
1204                  * scenarios (even 100% of the default ones).
1205                  */
1206                 unsigned char head_sha1[20];
1207                 int head_flag;
1208                 const char *head_ref;
1209                 head_ref = resolve_ref("HEAD", head_sha1, 1, &head_flag);
1210                 if (head_ref && (head_flag & REF_ISSYMREF) &&
1211                     !strcmp(head_ref, lock->ref_name))
1212                         log_ref_write("HEAD", lock->old_sha1, sha1, logmsg);
1213         }
1214         if (commit_ref(lock)) {
1215                 error("Couldn't set %s", lock->ref_name);
1216                 unlock_ref(lock);
1217                 return -1;
1218         }
1219         unlock_ref(lock);
1220         return 0;
1221 }
1222
1223 int create_symref(const char *ref_target, const char *refs_heads_master,
1224                   const char *logmsg)
1225 {
1226         const char *lockpath;
1227         char ref[1000];
1228         int fd, len, written;
1229         char *git_HEAD = xstrdup(git_path("%s", ref_target));
1230         unsigned char old_sha1[20], new_sha1[20];
1231
1232         if (logmsg && read_ref(ref_target, old_sha1))
1233                 hashclr(old_sha1);
1234
1235         if (safe_create_leading_directories(git_HEAD) < 0)
1236                 return error("unable to create directory for %s", git_HEAD);
1237
1238 #ifndef NO_SYMLINK_HEAD
1239         if (prefer_symlink_refs) {
1240                 unlink(git_HEAD);
1241                 if (!symlink(refs_heads_master, git_HEAD))
1242                         goto done;
1243                 fprintf(stderr, "no symlink - falling back to symbolic ref\n");
1244         }
1245 #endif
1246
1247         len = snprintf(ref, sizeof(ref), "ref: %s\n", refs_heads_master);
1248         if (sizeof(ref) <= len) {
1249                 error("refname too long: %s", refs_heads_master);
1250                 goto error_free_return;
1251         }
1252         lockpath = mkpath("%s.lock", git_HEAD);
1253         fd = open(lockpath, O_CREAT | O_EXCL | O_WRONLY, 0666);
1254         if (fd < 0) {
1255                 error("Unable to open %s for writing", lockpath);
1256                 goto error_free_return;
1257         }
1258         written = write_in_full(fd, ref, len);
1259         if (close(fd) != 0 || written != len) {
1260                 error("Unable to write to %s", lockpath);
1261                 goto error_unlink_return;
1262         }
1263         if (rename(lockpath, git_HEAD) < 0) {
1264                 error("Unable to create %s", git_HEAD);
1265                 goto error_unlink_return;
1266         }
1267         if (adjust_shared_perm(git_HEAD)) {
1268                 error("Unable to fix permissions on %s", lockpath);
1269         error_unlink_return:
1270                 unlink(lockpath);
1271         error_free_return:
1272                 free(git_HEAD);
1273                 return -1;
1274         }
1275
1276 #ifndef NO_SYMLINK_HEAD
1277         done:
1278 #endif
1279         if (logmsg && !read_ref(refs_heads_master, new_sha1))
1280                 log_ref_write(ref_target, old_sha1, new_sha1, logmsg);
1281
1282         free(git_HEAD);
1283         return 0;
1284 }
1285
1286 static char *ref_msg(const char *line, const char *endp)
1287 {
1288         const char *ep;
1289         line += 82;
1290         ep = memchr(line, '\n', endp - line);
1291         if (!ep)
1292                 ep = endp;
1293         return xmemdupz(line, ep - line);
1294 }
1295
1296 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)
1297 {
1298         const char *logfile, *logdata, *logend, *rec, *lastgt, *lastrec;
1299         char *tz_c;
1300         int logfd, tz, reccnt = 0;
1301         struct stat st;
1302         unsigned long date;
1303         unsigned char logged_sha1[20];
1304         void *log_mapped;
1305         size_t mapsz;
1306
1307         logfile = git_path("logs/%s", ref);
1308         logfd = open(logfile, O_RDONLY, 0);
1309         if (logfd < 0)
1310                 die("Unable to read log %s: %s", logfile, strerror(errno));
1311         fstat(logfd, &st);
1312         if (!st.st_size)
1313                 die("Log %s is empty.", logfile);
1314         mapsz = xsize_t(st.st_size);
1315         log_mapped = xmmap(NULL, mapsz, PROT_READ, MAP_PRIVATE, logfd, 0);
1316         logdata = log_mapped;
1317         close(logfd);
1318
1319         lastrec = NULL;
1320         rec = logend = logdata + st.st_size;
1321         while (logdata < rec) {
1322                 reccnt++;
1323                 if (logdata < rec && *(rec-1) == '\n')
1324                         rec--;
1325                 lastgt = NULL;
1326                 while (logdata < rec && *(rec-1) != '\n') {
1327                         rec--;
1328                         if (*rec == '>')
1329                                 lastgt = rec;
1330                 }
1331                 if (!lastgt)
1332                         die("Log %s is corrupt.", logfile);
1333                 date = strtoul(lastgt + 1, &tz_c, 10);
1334                 if (date <= at_time || cnt == 0) {
1335                         tz = strtoul(tz_c, NULL, 10);
1336                         if (msg)
1337                                 *msg = ref_msg(rec, logend);
1338                         if (cutoff_time)
1339                                 *cutoff_time = date;
1340                         if (cutoff_tz)
1341                                 *cutoff_tz = tz;
1342                         if (cutoff_cnt)
1343                                 *cutoff_cnt = reccnt - 1;
1344                         if (lastrec) {
1345                                 if (get_sha1_hex(lastrec, logged_sha1))
1346                                         die("Log %s is corrupt.", logfile);
1347                                 if (get_sha1_hex(rec + 41, sha1))
1348                                         die("Log %s is corrupt.", logfile);
1349                                 if (hashcmp(logged_sha1, sha1)) {
1350                                         fprintf(stderr,
1351                                                 "warning: Log %s has gap after %s.\n",
1352                                                 logfile, show_date(date, tz, DATE_RFC2822));
1353                                 }
1354                         }
1355                         else if (date == at_time) {
1356                                 if (get_sha1_hex(rec + 41, sha1))
1357                                         die("Log %s is corrupt.", logfile);
1358                         }
1359                         else {
1360                                 if (get_sha1_hex(rec + 41, logged_sha1))
1361                                         die("Log %s is corrupt.", logfile);
1362                                 if (hashcmp(logged_sha1, sha1)) {
1363                                         fprintf(stderr,
1364                                                 "warning: Log %s unexpectedly ended on %s.\n",
1365                                                 logfile, show_date(date, tz, DATE_RFC2822));
1366                                 }
1367                         }
1368                         munmap(log_mapped, mapsz);
1369                         return 0;
1370                 }
1371                 lastrec = rec;
1372                 if (cnt > 0)
1373                         cnt--;
1374         }
1375
1376         rec = logdata;
1377         while (rec < logend && *rec != '>' && *rec != '\n')
1378                 rec++;
1379         if (rec == logend || *rec == '\n')
1380                 die("Log %s is corrupt.", logfile);
1381         date = strtoul(rec + 1, &tz_c, 10);
1382         tz = strtoul(tz_c, NULL, 10);
1383         if (get_sha1_hex(logdata, sha1))
1384                 die("Log %s is corrupt.", logfile);
1385         if (msg)
1386                 *msg = ref_msg(logdata, logend);
1387         munmap(log_mapped, mapsz);
1388
1389         if (cutoff_time)
1390                 *cutoff_time = date;
1391         if (cutoff_tz)
1392                 *cutoff_tz = tz;
1393         if (cutoff_cnt)
1394                 *cutoff_cnt = reccnt;
1395         return 1;
1396 }
1397
1398 int for_each_reflog_ent(const char *ref, each_reflog_ent_fn fn, void *cb_data)
1399 {
1400         const char *logfile;
1401         FILE *logfp;
1402         char buf[1024];
1403         int ret = 0;
1404
1405         logfile = git_path("logs/%s", ref);
1406         logfp = fopen(logfile, "r");
1407         if (!logfp)
1408                 return -1;
1409         while (fgets(buf, sizeof(buf), logfp)) {
1410                 unsigned char osha1[20], nsha1[20];
1411                 char *email_end, *message;
1412                 unsigned long timestamp;
1413                 int len, tz;
1414
1415                 /* old SP new SP name <email> SP time TAB msg LF */
1416                 len = strlen(buf);
1417                 if (len < 83 || buf[len-1] != '\n' ||
1418                     get_sha1_hex(buf, osha1) || buf[40] != ' ' ||
1419                     get_sha1_hex(buf + 41, nsha1) || buf[81] != ' ' ||
1420                     !(email_end = strchr(buf + 82, '>')) ||
1421                     email_end[1] != ' ' ||
1422                     !(timestamp = strtoul(email_end + 2, &message, 10)) ||
1423                     !message || message[0] != ' ' ||
1424                     (message[1] != '+' && message[1] != '-') ||
1425                     !isdigit(message[2]) || !isdigit(message[3]) ||
1426                     !isdigit(message[4]) || !isdigit(message[5]))
1427                         continue; /* corrupt? */
1428                 email_end[1] = '\0';
1429                 tz = strtol(message + 1, NULL, 10);
1430                 if (message[6] != '\t')
1431                         message += 6;
1432                 else
1433                         message += 7;
1434                 ret = fn(osha1, nsha1, buf+82, timestamp, tz, message, cb_data);
1435                 if (ret)
1436                         break;
1437         }
1438         fclose(logfp);
1439         return ret;
1440 }
1441
1442 static int do_for_each_reflog(const char *base, each_ref_fn fn, void *cb_data)
1443 {
1444         DIR *dir = opendir(git_path("logs/%s", base));
1445         int retval = 0;
1446
1447         if (dir) {
1448                 struct dirent *de;
1449                 int baselen = strlen(base);
1450                 char *log = xmalloc(baselen + 257);
1451
1452                 memcpy(log, base, baselen);
1453                 if (baselen && base[baselen-1] != '/')
1454                         log[baselen++] = '/';
1455
1456                 while ((de = readdir(dir)) != NULL) {
1457                         struct stat st;
1458                         int namelen;
1459
1460                         if (de->d_name[0] == '.')
1461                                 continue;
1462                         namelen = strlen(de->d_name);
1463                         if (namelen > 255)
1464                                 continue;
1465                         if (has_extension(de->d_name, ".lock"))
1466                                 continue;
1467                         memcpy(log + baselen, de->d_name, namelen+1);
1468                         if (stat(git_path("logs/%s", log), &st) < 0)
1469                                 continue;
1470                         if (S_ISDIR(st.st_mode)) {
1471                                 retval = do_for_each_reflog(log, fn, cb_data);
1472                         } else {
1473                                 unsigned char sha1[20];
1474                                 if (!resolve_ref(log, sha1, 0, NULL))
1475                                         retval = error("bad ref for %s", log);
1476                                 else
1477                                         retval = fn(log, sha1, 0, cb_data);
1478                         }
1479                         if (retval)
1480                                 break;
1481                 }
1482                 free(log);
1483                 closedir(dir);
1484         }
1485         else if (*base)
1486                 return errno;
1487         return retval;
1488 }
1489
1490 int for_each_reflog(each_ref_fn fn, void *cb_data)
1491 {
1492         return do_for_each_reflog("", fn, cb_data);
1493 }
1494
1495 int update_ref(const char *action, const char *refname,
1496                 const unsigned char *sha1, const unsigned char *oldval,
1497                 int flags, enum action_on_err onerr)
1498 {
1499         static struct ref_lock *lock;
1500         lock = lock_any_ref_for_update(refname, oldval, flags);
1501         if (!lock) {
1502                 const char *str = "Cannot lock the ref '%s'.";
1503                 switch (onerr) {
1504                 case MSG_ON_ERR: error(str, refname); break;
1505                 case DIE_ON_ERR: die(str, refname); break;
1506                 case QUIET_ON_ERR: break;
1507                 }
1508                 return 1;
1509         }
1510         if (write_ref_sha1(lock, sha1, action) < 0) {
1511                 const char *str = "Cannot update the ref '%s'.";
1512                 switch (onerr) {
1513                 case MSG_ON_ERR: error(str, refname); break;
1514                 case DIE_ON_ERR: die(str, refname); break;
1515                 case QUIET_ON_ERR: break;
1516                 }
1517                 return 1;
1518         }
1519         return 0;
1520 }
1521
1522 struct ref *find_ref_by_name(struct ref *list, const char *name)
1523 {
1524         for ( ; list; list = list->next)
1525                 if (!strcmp(list->name, name))
1526                         return list;
1527         return NULL;
1528 }