refs.con commit Merge branch 'js/remote' (ae90e16)
   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
  10struct 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
  18static 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
  46static 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 */
  67static 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 */
 154static struct cached_refs {
 155        char did_loose;
 156        char did_packed;
 157        struct ref_list *loose;
 158        struct ref_list *packed;
 159} cached_refs;
 160static struct ref_list *current_ref;
 161
 162static 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
 171static 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
 183static 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
 218static 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
 232static 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
 277static 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
 290static 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
 317static 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
 351int 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
 369const 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
 462int 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
 469static 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
 484int 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
 519fallback:
 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
 531static 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
 563end_each:
 564        current_ref = NULL;
 565        return retval;
 566}
 567
 568int 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
 578int for_each_ref(each_ref_fn fn, void *cb_data)
 579{
 580        return do_for_each_ref("refs/", fn, 0, cb_data);
 581}
 582
 583int 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
 588int 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
 593int 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
 608static 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
 621int 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
 666const 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
 676const char *ref_fetch_rules[] = {
 677        "%.*s",
 678        "refs/%.*s",
 679        "refs/heads/%.*s",
 680        NULL
 681};
 682
 683int 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
 697static 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
 714static 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
 733static 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
 756static 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
 828struct 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
 837struct 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
 848static struct lock_file packlock;
 849
 850static 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
 885int 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
 920int 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
1036int 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
1044int 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
1052void 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 */
1067static 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
1088static 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
1149static int is_branch(const char *refname)
1150{
1151        return !strcmp(refname, "HEAD") || !prefixcmp(refname, "refs/heads/");
1152}
1153
1154int 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
1223int 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
1286static 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
1296int 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
1398int 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
1442static 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
1490int for_each_reflog(each_ref_fn fn, void *cb_data)
1491{
1492        return do_for_each_reflog("", fn, cb_data);
1493}
1494
1495int 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
1522struct 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}