refs.con commit Merge branch 'maint' (304d058)
   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 struct ref_list *extra_refs;
 163
 164static void free_ref_list(struct ref_list *list)
 165{
 166        struct ref_list *next;
 167        for ( ; list; list = next) {
 168                next = list->next;
 169                free(list);
 170        }
 171}
 172
 173static void invalidate_cached_refs(void)
 174{
 175        struct cached_refs *ca = &cached_refs;
 176
 177        if (ca->did_loose && ca->loose)
 178                free_ref_list(ca->loose);
 179        if (ca->did_packed && ca->packed)
 180                free_ref_list(ca->packed);
 181        ca->loose = ca->packed = NULL;
 182        ca->did_loose = ca->did_packed = 0;
 183}
 184
 185static void read_packed_refs(FILE *f, struct cached_refs *cached_refs)
 186{
 187        struct ref_list *list = NULL;
 188        struct ref_list *last = NULL;
 189        char refline[PATH_MAX];
 190        int flag = REF_ISPACKED;
 191
 192        while (fgets(refline, sizeof(refline), f)) {
 193                unsigned char sha1[20];
 194                const char *name;
 195                static const char header[] = "# pack-refs with:";
 196
 197                if (!strncmp(refline, header, sizeof(header)-1)) {
 198                        const char *traits = refline + sizeof(header) - 1;
 199                        if (strstr(traits, " peeled "))
 200                                flag |= REF_KNOWS_PEELED;
 201                        /* perhaps other traits later as well */
 202                        continue;
 203                }
 204
 205                name = parse_ref_line(refline, sha1);
 206                if (name) {
 207                        list = add_ref(name, sha1, flag, list, &last);
 208                        continue;
 209                }
 210                if (last &&
 211                    refline[0] == '^' &&
 212                    strlen(refline) == 42 &&
 213                    refline[41] == '\n' &&
 214                    !get_sha1_hex(refline + 1, sha1))
 215                        hashcpy(last->peeled, sha1);
 216        }
 217        cached_refs->packed = sort_ref_list(list);
 218}
 219
 220void add_extra_ref(const char *name, const unsigned char *sha1, int flag)
 221{
 222        extra_refs = add_ref(name, sha1, flag, extra_refs, NULL);
 223}
 224
 225void clear_extra_refs(void)
 226{
 227        free_ref_list(extra_refs);
 228        extra_refs = NULL;
 229}
 230
 231static struct ref_list *get_packed_refs(void)
 232{
 233        if (!cached_refs.did_packed) {
 234                FILE *f = fopen(git_path("packed-refs"), "r");
 235                cached_refs.packed = NULL;
 236                if (f) {
 237                        read_packed_refs(f, &cached_refs);
 238                        fclose(f);
 239                }
 240                cached_refs.did_packed = 1;
 241        }
 242        return cached_refs.packed;
 243}
 244
 245static struct ref_list *get_ref_dir(const char *base, struct ref_list *list)
 246{
 247        DIR *dir = opendir(git_path("%s", base));
 248
 249        if (dir) {
 250                struct dirent *de;
 251                int baselen = strlen(base);
 252                char *ref = xmalloc(baselen + 257);
 253
 254                memcpy(ref, base, baselen);
 255                if (baselen && base[baselen-1] != '/')
 256                        ref[baselen++] = '/';
 257
 258                while ((de = readdir(dir)) != NULL) {
 259                        unsigned char sha1[20];
 260                        struct stat st;
 261                        int flag;
 262                        int namelen;
 263
 264                        if (de->d_name[0] == '.')
 265                                continue;
 266                        namelen = strlen(de->d_name);
 267                        if (namelen > 255)
 268                                continue;
 269                        if (has_extension(de->d_name, ".lock"))
 270                                continue;
 271                        memcpy(ref + baselen, de->d_name, namelen+1);
 272                        if (stat(git_path("%s", ref), &st) < 0)
 273                                continue;
 274                        if (S_ISDIR(st.st_mode)) {
 275                                list = get_ref_dir(ref, list);
 276                                continue;
 277                        }
 278                        if (!resolve_ref(ref, sha1, 1, &flag)) {
 279                                error("%s points nowhere!", ref);
 280                                continue;
 281                        }
 282                        list = add_ref(ref, sha1, flag, list, NULL);
 283                }
 284                free(ref);
 285                closedir(dir);
 286        }
 287        return sort_ref_list(list);
 288}
 289
 290static struct ref_list *get_loose_refs(void)
 291{
 292        if (!cached_refs.did_loose) {
 293                cached_refs.loose = get_ref_dir("refs", NULL);
 294                cached_refs.did_loose = 1;
 295        }
 296        return cached_refs.loose;
 297}
 298
 299/* We allow "recursive" symbolic refs. Only within reason, though */
 300#define MAXDEPTH 5
 301#define MAXREFLEN (1024)
 302
 303static int resolve_gitlink_packed_ref(char *name, int pathlen, const char *refname, unsigned char *result)
 304{
 305        FILE *f;
 306        struct cached_refs refs;
 307        struct ref_list *ref;
 308        int retval;
 309
 310        strcpy(name + pathlen, "packed-refs");
 311        f = fopen(name, "r");
 312        if (!f)
 313                return -1;
 314        read_packed_refs(f, &refs);
 315        fclose(f);
 316        ref = refs.packed;
 317        retval = -1;
 318        while (ref) {
 319                if (!strcmp(ref->name, refname)) {
 320                        retval = 0;
 321                        memcpy(result, ref->sha1, 20);
 322                        break;
 323                }
 324                ref = ref->next;
 325        }
 326        free_ref_list(refs.packed);
 327        return retval;
 328}
 329
 330static int resolve_gitlink_ref_recursive(char *name, int pathlen, const char *refname, unsigned char *result, int recursion)
 331{
 332        int fd, len = strlen(refname);
 333        char buffer[128], *p;
 334
 335        if (recursion > MAXDEPTH || len > MAXREFLEN)
 336                return -1;
 337        memcpy(name + pathlen, refname, len+1);
 338        fd = open(name, O_RDONLY);
 339        if (fd < 0)
 340                return resolve_gitlink_packed_ref(name, pathlen, refname, result);
 341
 342        len = read(fd, buffer, sizeof(buffer)-1);
 343        close(fd);
 344        if (len < 0)
 345                return -1;
 346        while (len && isspace(buffer[len-1]))
 347                len--;
 348        buffer[len] = 0;
 349
 350        /* Was it a detached head or an old-fashioned symlink? */
 351        if (!get_sha1_hex(buffer, result))
 352                return 0;
 353
 354        /* Symref? */
 355        if (strncmp(buffer, "ref:", 4))
 356                return -1;
 357        p = buffer + 4;
 358        while (isspace(*p))
 359                p++;
 360
 361        return resolve_gitlink_ref_recursive(name, pathlen, p, result, recursion+1);
 362}
 363
 364int resolve_gitlink_ref(const char *path, const char *refname, unsigned char *result)
 365{
 366        int len = strlen(path), retval;
 367        char *gitdir;
 368        const char *tmp;
 369
 370        while (len && path[len-1] == '/')
 371                len--;
 372        if (!len)
 373                return -1;
 374        gitdir = xmalloc(len + MAXREFLEN + 8);
 375        memcpy(gitdir, path, len);
 376        memcpy(gitdir + len, "/.git", 6);
 377        len += 5;
 378
 379        tmp = read_gitfile_gently(gitdir);
 380        if (tmp) {
 381                free(gitdir);
 382                len = strlen(tmp);
 383                gitdir = xmalloc(len + MAXREFLEN + 3);
 384                memcpy(gitdir, tmp, len);
 385        }
 386        gitdir[len] = '/';
 387        gitdir[++len] = '\0';
 388        retval = resolve_gitlink_ref_recursive(gitdir, len, refname, result, 0);
 389        free(gitdir);
 390        return retval;
 391}
 392
 393/*
 394 * If the "reading" argument is set, this function finds out what _object_
 395 * the ref points at by "reading" the ref.  The ref, if it is not symbolic,
 396 * has to exist, and if it is symbolic, it has to point at an existing ref,
 397 * because the "read" goes through the symref to the ref it points at.
 398 *
 399 * The access that is not "reading" may often be "writing", but does not
 400 * have to; it can be merely checking _where it leads to_. If it is a
 401 * prelude to "writing" to the ref, a write to a symref that points at
 402 * yet-to-be-born ref will create the real ref pointed by the symref.
 403 * reading=0 allows the caller to check where such a symref leads to.
 404 */
 405const char *resolve_ref(const char *ref, unsigned char *sha1, int reading, int *flag)
 406{
 407        int depth = MAXDEPTH;
 408        ssize_t len;
 409        char buffer[256];
 410        static char ref_buffer[256];
 411
 412        if (flag)
 413                *flag = 0;
 414
 415        for (;;) {
 416                const char *path = git_path("%s", ref);
 417                struct stat st;
 418                char *buf;
 419                int fd;
 420
 421                if (--depth < 0)
 422                        return NULL;
 423
 424                /* Special case: non-existing file. */
 425                if (lstat(path, &st) < 0) {
 426                        struct ref_list *list = get_packed_refs();
 427                        while (list) {
 428                                if (!strcmp(ref, list->name)) {
 429                                        hashcpy(sha1, list->sha1);
 430                                        if (flag)
 431                                                *flag |= REF_ISPACKED;
 432                                        return ref;
 433                                }
 434                                list = list->next;
 435                        }
 436                        if (reading || errno != ENOENT)
 437                                return NULL;
 438                        hashclr(sha1);
 439                        return ref;
 440                }
 441
 442                /* Follow "normalized" - ie "refs/.." symlinks by hand */
 443                if (S_ISLNK(st.st_mode)) {
 444                        len = readlink(path, buffer, sizeof(buffer)-1);
 445                        if (len >= 5 && !memcmp("refs/", buffer, 5)) {
 446                                buffer[len] = 0;
 447                                strcpy(ref_buffer, buffer);
 448                                ref = ref_buffer;
 449                                if (flag)
 450                                        *flag |= REF_ISSYMREF;
 451                                continue;
 452                        }
 453                }
 454
 455                /* Is it a directory? */
 456                if (S_ISDIR(st.st_mode)) {
 457                        errno = EISDIR;
 458                        return NULL;
 459                }
 460
 461                /*
 462                 * Anything else, just open it and try to use it as
 463                 * a ref
 464                 */
 465                fd = open(path, O_RDONLY);
 466                if (fd < 0)
 467                        return NULL;
 468                len = read_in_full(fd, buffer, sizeof(buffer)-1);
 469                close(fd);
 470
 471                /*
 472                 * Is it a symbolic ref?
 473                 */
 474                if (len < 4 || memcmp("ref:", buffer, 4))
 475                        break;
 476                buf = buffer + 4;
 477                len -= 4;
 478                while (len && isspace(*buf))
 479                        buf++, len--;
 480                while (len && isspace(buf[len-1]))
 481                        len--;
 482                buf[len] = 0;
 483                memcpy(ref_buffer, buf, len + 1);
 484                ref = ref_buffer;
 485                if (flag)
 486                        *flag |= REF_ISSYMREF;
 487        }
 488        if (len < 40 || get_sha1_hex(buffer, sha1))
 489                return NULL;
 490        return ref;
 491}
 492
 493int read_ref(const char *ref, unsigned char *sha1)
 494{
 495        if (resolve_ref(ref, sha1, 1, NULL))
 496                return 0;
 497        return -1;
 498}
 499
 500static int do_one_ref(const char *base, each_ref_fn fn, int trim,
 501                      void *cb_data, struct ref_list *entry)
 502{
 503        if (strncmp(base, entry->name, trim))
 504                return 0;
 505        if (is_null_sha1(entry->sha1))
 506                return 0;
 507        if (!has_sha1_file(entry->sha1)) {
 508                error("%s does not point to a valid object!", entry->name);
 509                return 0;
 510        }
 511        current_ref = entry;
 512        return fn(entry->name + trim, entry->sha1, entry->flag, cb_data);
 513}
 514
 515int peel_ref(const char *ref, unsigned char *sha1)
 516{
 517        int flag;
 518        unsigned char base[20];
 519        struct object *o;
 520
 521        if (current_ref && (current_ref->name == ref
 522                || !strcmp(current_ref->name, ref))) {
 523                if (current_ref->flag & REF_KNOWS_PEELED) {
 524                        hashcpy(sha1, current_ref->peeled);
 525                        return 0;
 526                }
 527                hashcpy(base, current_ref->sha1);
 528                goto fallback;
 529        }
 530
 531        if (!resolve_ref(ref, base, 1, &flag))
 532                return -1;
 533
 534        if ((flag & REF_ISPACKED)) {
 535                struct ref_list *list = get_packed_refs();
 536
 537                while (list) {
 538                        if (!strcmp(list->name, ref)) {
 539                                if (list->flag & REF_KNOWS_PEELED) {
 540                                        hashcpy(sha1, list->peeled);
 541                                        return 0;
 542                                }
 543                                /* older pack-refs did not leave peeled ones */
 544                                break;
 545                        }
 546                        list = list->next;
 547                }
 548        }
 549
 550fallback:
 551        o = parse_object(base);
 552        if (o && o->type == OBJ_TAG) {
 553                o = deref_tag(o, ref, 0);
 554                if (o) {
 555                        hashcpy(sha1, o->sha1);
 556                        return 0;
 557                }
 558        }
 559        return -1;
 560}
 561
 562static int do_for_each_ref(const char *base, each_ref_fn fn, int trim,
 563                           void *cb_data)
 564{
 565        int retval = 0;
 566        struct ref_list *packed = get_packed_refs();
 567        struct ref_list *loose = get_loose_refs();
 568
 569        struct ref_list *extra;
 570
 571        for (extra = extra_refs; extra; extra = extra->next)
 572                retval = do_one_ref(base, fn, trim, cb_data, extra);
 573
 574        while (packed && loose) {
 575                struct ref_list *entry;
 576                int cmp = strcmp(packed->name, loose->name);
 577                if (!cmp) {
 578                        packed = packed->next;
 579                        continue;
 580                }
 581                if (cmp > 0) {
 582                        entry = loose;
 583                        loose = loose->next;
 584                } else {
 585                        entry = packed;
 586                        packed = packed->next;
 587                }
 588                retval = do_one_ref(base, fn, trim, cb_data, entry);
 589                if (retval)
 590                        goto end_each;
 591        }
 592
 593        for (packed = packed ? packed : loose; packed; packed = packed->next) {
 594                retval = do_one_ref(base, fn, trim, cb_data, packed);
 595                if (retval)
 596                        goto end_each;
 597        }
 598
 599end_each:
 600        current_ref = NULL;
 601        return retval;
 602}
 603
 604int head_ref(each_ref_fn fn, void *cb_data)
 605{
 606        unsigned char sha1[20];
 607        int flag;
 608
 609        if (resolve_ref("HEAD", sha1, 1, &flag))
 610                return fn("HEAD", sha1, flag, cb_data);
 611        return 0;
 612}
 613
 614int for_each_ref(each_ref_fn fn, void *cb_data)
 615{
 616        return do_for_each_ref("refs/", fn, 0, cb_data);
 617}
 618
 619int for_each_tag_ref(each_ref_fn fn, void *cb_data)
 620{
 621        return do_for_each_ref("refs/tags/", fn, 10, cb_data);
 622}
 623
 624int for_each_branch_ref(each_ref_fn fn, void *cb_data)
 625{
 626        return do_for_each_ref("refs/heads/", fn, 11, cb_data);
 627}
 628
 629int for_each_remote_ref(each_ref_fn fn, void *cb_data)
 630{
 631        return do_for_each_ref("refs/remotes/", fn, 13, cb_data);
 632}
 633
 634/*
 635 * Make sure "ref" is something reasonable to have under ".git/refs/";
 636 * We do not like it if:
 637 *
 638 * - any path component of it begins with ".", or
 639 * - it has double dots "..", or
 640 * - it has ASCII control character, "~", "^", ":" or SP, anywhere, or
 641 * - it ends with a "/".
 642 */
 643
 644static inline int bad_ref_char(int ch)
 645{
 646        if (((unsigned) ch) <= ' ' ||
 647            ch == '~' || ch == '^' || ch == ':')
 648                return 1;
 649        /* 2.13 Pattern Matching Notation */
 650        if (ch == '?' || ch == '[') /* Unsupported */
 651                return 1;
 652        if (ch == '*') /* Supported at the end */
 653                return 2;
 654        return 0;
 655}
 656
 657int check_ref_format(const char *ref)
 658{
 659        int ch, level, bad_type;
 660        const char *cp = ref;
 661
 662        level = 0;
 663        while (1) {
 664                while ((ch = *cp++) == '/')
 665                        ; /* tolerate duplicated slashes */
 666                if (!ch)
 667                        /* should not end with slashes */
 668                        return CHECK_REF_FORMAT_ERROR;
 669
 670                /* we are at the beginning of the path component */
 671                if (ch == '.')
 672                        return CHECK_REF_FORMAT_ERROR;
 673                bad_type = bad_ref_char(ch);
 674                if (bad_type) {
 675                        return (bad_type == 2 && !*cp)
 676                                ? CHECK_REF_FORMAT_WILDCARD
 677                                : CHECK_REF_FORMAT_ERROR;
 678                }
 679
 680                /* scan the rest of the path component */
 681                while ((ch = *cp++) != 0) {
 682                        bad_type = bad_ref_char(ch);
 683                        if (bad_type) {
 684                                return (bad_type == 2 && !*cp)
 685                                        ? CHECK_REF_FORMAT_WILDCARD
 686                                        : CHECK_REF_FORMAT_ERROR;
 687                        }
 688                        if (ch == '/')
 689                                break;
 690                        if (ch == '.' && *cp == '.')
 691                                return CHECK_REF_FORMAT_ERROR;
 692                }
 693                level++;
 694                if (!ch) {
 695                        if (level < 2)
 696                                return CHECK_REF_FORMAT_ONELEVEL;
 697                        return CHECK_REF_FORMAT_OK;
 698                }
 699        }
 700}
 701
 702const char *ref_rev_parse_rules[] = {
 703        "%.*s",
 704        "refs/%.*s",
 705        "refs/tags/%.*s",
 706        "refs/heads/%.*s",
 707        "refs/remotes/%.*s",
 708        "refs/remotes/%.*s/HEAD",
 709        NULL
 710};
 711
 712const char *ref_fetch_rules[] = {
 713        "%.*s",
 714        "refs/%.*s",
 715        "refs/heads/%.*s",
 716        NULL
 717};
 718
 719int refname_match(const char *abbrev_name, const char *full_name, const char **rules)
 720{
 721        const char **p;
 722        const int abbrev_name_len = strlen(abbrev_name);
 723
 724        for (p = rules; *p; p++) {
 725                if (!strcmp(full_name, mkpath(*p, abbrev_name_len, abbrev_name))) {
 726                        return 1;
 727                }
 728        }
 729
 730        return 0;
 731}
 732
 733static struct ref_lock *verify_lock(struct ref_lock *lock,
 734        const unsigned char *old_sha1, int mustexist)
 735{
 736        if (!resolve_ref(lock->ref_name, lock->old_sha1, mustexist, NULL)) {
 737                error("Can't verify ref %s", lock->ref_name);
 738                unlock_ref(lock);
 739                return NULL;
 740        }
 741        if (hashcmp(lock->old_sha1, old_sha1)) {
 742                error("Ref %s is at %s but expected %s", lock->ref_name,
 743                        sha1_to_hex(lock->old_sha1), sha1_to_hex(old_sha1));
 744                unlock_ref(lock);
 745                return NULL;
 746        }
 747        return lock;
 748}
 749
 750static int remove_empty_directories(const char *file)
 751{
 752        /* we want to create a file but there is a directory there;
 753         * if that is an empty directory (or a directory that contains
 754         * only empty directories), remove them.
 755         */
 756        struct strbuf path;
 757        int result;
 758
 759        strbuf_init(&path, 20);
 760        strbuf_addstr(&path, file);
 761
 762        result = remove_dir_recursively(&path, 1);
 763
 764        strbuf_release(&path);
 765
 766        return result;
 767}
 768
 769static int is_refname_available(const char *ref, const char *oldref,
 770                                struct ref_list *list, int quiet)
 771{
 772        int namlen = strlen(ref); /* e.g. 'foo/bar' */
 773        while (list) {
 774                /* list->name could be 'foo' or 'foo/bar/baz' */
 775                if (!oldref || strcmp(oldref, list->name)) {
 776                        int len = strlen(list->name);
 777                        int cmplen = (namlen < len) ? namlen : len;
 778                        const char *lead = (namlen < len) ? list->name : ref;
 779                        if (!strncmp(ref, list->name, cmplen) &&
 780                            lead[cmplen] == '/') {
 781                                if (!quiet)
 782                                        error("'%s' exists; cannot create '%s'",
 783                                              list->name, ref);
 784                                return 0;
 785                        }
 786                }
 787                list = list->next;
 788        }
 789        return 1;
 790}
 791
 792static struct ref_lock *lock_ref_sha1_basic(const char *ref, const unsigned char *old_sha1, int flags, int *type_p)
 793{
 794        char *ref_file;
 795        const char *orig_ref = ref;
 796        struct ref_lock *lock;
 797        struct stat st;
 798        int last_errno = 0;
 799        int type, lflags;
 800        int mustexist = (old_sha1 && !is_null_sha1(old_sha1));
 801
 802        lock = xcalloc(1, sizeof(struct ref_lock));
 803        lock->lock_fd = -1;
 804
 805        ref = resolve_ref(ref, lock->old_sha1, mustexist, &type);
 806        if (!ref && errno == EISDIR) {
 807                /* we are trying to lock foo but we used to
 808                 * have foo/bar which now does not exist;
 809                 * it is normal for the empty directory 'foo'
 810                 * to remain.
 811                 */
 812                ref_file = git_path("%s", orig_ref);
 813                if (remove_empty_directories(ref_file)) {
 814                        last_errno = errno;
 815                        error("there are still refs under '%s'", orig_ref);
 816                        goto error_return;
 817                }
 818                ref = resolve_ref(orig_ref, lock->old_sha1, mustexist, &type);
 819        }
 820        if (type_p)
 821            *type_p = type;
 822        if (!ref) {
 823                last_errno = errno;
 824                error("unable to resolve reference %s: %s",
 825                        orig_ref, strerror(errno));
 826                goto error_return;
 827        }
 828        /* When the ref did not exist and we are creating it,
 829         * make sure there is no existing ref that is packed
 830         * whose name begins with our refname, nor a ref whose
 831         * name is a proper prefix of our refname.
 832         */
 833        if (is_null_sha1(lock->old_sha1) &&
 834            !is_refname_available(ref, NULL, get_packed_refs(), 0))
 835                goto error_return;
 836
 837        lock->lk = xcalloc(1, sizeof(struct lock_file));
 838
 839        lflags = LOCK_DIE_ON_ERROR;
 840        if (flags & REF_NODEREF) {
 841                ref = orig_ref;
 842                lflags |= LOCK_NODEREF;
 843        }
 844        lock->ref_name = xstrdup(ref);
 845        lock->orig_ref_name = xstrdup(orig_ref);
 846        ref_file = git_path("%s", ref);
 847        if (lstat(ref_file, &st) && errno == ENOENT)
 848                lock->force_write = 1;
 849        if ((flags & REF_NODEREF) && (type & REF_ISSYMREF))
 850                lock->force_write = 1;
 851
 852        if (safe_create_leading_directories(ref_file)) {
 853                last_errno = errno;
 854                error("unable to create directory for %s", ref_file);
 855                goto error_return;
 856        }
 857
 858        lock->lock_fd = hold_lock_file_for_update(lock->lk, ref_file, lflags);
 859        return old_sha1 ? verify_lock(lock, old_sha1, mustexist) : lock;
 860
 861 error_return:
 862        unlock_ref(lock);
 863        errno = last_errno;
 864        return NULL;
 865}
 866
 867struct ref_lock *lock_ref_sha1(const char *ref, const unsigned char *old_sha1)
 868{
 869        char refpath[PATH_MAX];
 870        if (check_ref_format(ref))
 871                return NULL;
 872        strcpy(refpath, mkpath("refs/%s", ref));
 873        return lock_ref_sha1_basic(refpath, old_sha1, 0, NULL);
 874}
 875
 876struct ref_lock *lock_any_ref_for_update(const char *ref, const unsigned char *old_sha1, int flags)
 877{
 878        switch (check_ref_format(ref)) {
 879        default:
 880                return NULL;
 881        case 0:
 882        case CHECK_REF_FORMAT_ONELEVEL:
 883                return lock_ref_sha1_basic(ref, old_sha1, flags, NULL);
 884        }
 885}
 886
 887static struct lock_file packlock;
 888
 889static int repack_without_ref(const char *refname)
 890{
 891        struct ref_list *list, *packed_ref_list;
 892        int fd;
 893        int found = 0;
 894
 895        packed_ref_list = get_packed_refs();
 896        for (list = packed_ref_list; list; list = list->next) {
 897                if (!strcmp(refname, list->name)) {
 898                        found = 1;
 899                        break;
 900                }
 901        }
 902        if (!found)
 903                return 0;
 904        fd = hold_lock_file_for_update(&packlock, git_path("packed-refs"), 0);
 905        if (fd < 0)
 906                return error("cannot delete '%s' from packed refs", refname);
 907
 908        for (list = packed_ref_list; list; list = list->next) {
 909                char line[PATH_MAX + 100];
 910                int len;
 911
 912                if (!strcmp(refname, list->name))
 913                        continue;
 914                len = snprintf(line, sizeof(line), "%s %s\n",
 915                               sha1_to_hex(list->sha1), list->name);
 916                /* this should not happen but just being defensive */
 917                if (len > sizeof(line))
 918                        die("too long a refname '%s'", list->name);
 919                write_or_die(fd, line, len);
 920        }
 921        return commit_lock_file(&packlock);
 922}
 923
 924int delete_ref(const char *refname, const unsigned char *sha1)
 925{
 926        struct ref_lock *lock;
 927        int err, i, ret = 0, flag = 0;
 928
 929        lock = lock_ref_sha1_basic(refname, sha1, 0, &flag);
 930        if (!lock)
 931                return 1;
 932        if (!(flag & REF_ISPACKED)) {
 933                /* loose */
 934                i = strlen(lock->lk->filename) - 5; /* .lock */
 935                lock->lk->filename[i] = 0;
 936                err = unlink(lock->lk->filename);
 937                if (err && errno != ENOENT) {
 938                        ret = 1;
 939                        error("unlink(%s) failed: %s",
 940                              lock->lk->filename, strerror(errno));
 941                }
 942                lock->lk->filename[i] = '.';
 943        }
 944        /* removing the loose one could have resurrected an earlier
 945         * packed one.  Also, if it was not loose we need to repack
 946         * without it.
 947         */
 948        ret |= repack_without_ref(refname);
 949
 950        err = unlink(git_path("logs/%s", lock->ref_name));
 951        if (err && errno != ENOENT)
 952                fprintf(stderr, "warning: unlink(%s) failed: %s",
 953                        git_path("logs/%s", lock->ref_name), strerror(errno));
 954        invalidate_cached_refs();
 955        unlock_ref(lock);
 956        return ret;
 957}
 958
 959int rename_ref(const char *oldref, const char *newref, const char *logmsg)
 960{
 961        static const char renamed_ref[] = "RENAMED-REF";
 962        unsigned char sha1[20], orig_sha1[20];
 963        int flag = 0, logmoved = 0;
 964        struct ref_lock *lock;
 965        struct stat loginfo;
 966        int log = !lstat(git_path("logs/%s", oldref), &loginfo);
 967
 968        if (S_ISLNK(loginfo.st_mode))
 969                return error("reflog for %s is a symlink", oldref);
 970
 971        if (!resolve_ref(oldref, orig_sha1, 1, &flag))
 972                return error("refname %s not found", oldref);
 973
 974        if (!is_refname_available(newref, oldref, get_packed_refs(), 0))
 975                return 1;
 976
 977        if (!is_refname_available(newref, oldref, get_loose_refs(), 0))
 978                return 1;
 979
 980        lock = lock_ref_sha1_basic(renamed_ref, NULL, 0, NULL);
 981        if (!lock)
 982                return error("unable to lock %s", renamed_ref);
 983        lock->force_write = 1;
 984        if (write_ref_sha1(lock, orig_sha1, logmsg))
 985                return error("unable to save current sha1 in %s", renamed_ref);
 986
 987        if (log && rename(git_path("logs/%s", oldref), git_path("tmp-renamed-log")))
 988                return error("unable to move logfile logs/%s to tmp-renamed-log: %s",
 989                        oldref, strerror(errno));
 990
 991        if (delete_ref(oldref, orig_sha1)) {
 992                error("unable to delete old %s", oldref);
 993                goto rollback;
 994        }
 995
 996        if (resolve_ref(newref, sha1, 1, &flag) && delete_ref(newref, sha1)) {
 997                if (errno==EISDIR) {
 998                        if (remove_empty_directories(git_path("%s", newref))) {
 999                                error("Directory not empty: %s", newref);
1000                                goto rollback;
1001                        }
1002                } else {
1003                        error("unable to delete existing %s", newref);
1004                        goto rollback;
1005                }
1006        }
1007
1008        if (log && safe_create_leading_directories(git_path("logs/%s", newref))) {
1009                error("unable to create directory for %s", newref);
1010                goto rollback;
1011        }
1012
1013 retry:
1014        if (log && rename(git_path("tmp-renamed-log"), git_path("logs/%s", newref))) {
1015                if (errno==EISDIR || errno==ENOTDIR) {
1016                        /*
1017                         * rename(a, b) when b is an existing
1018                         * directory ought to result in ISDIR, but
1019                         * Solaris 5.8 gives ENOTDIR.  Sheesh.
1020                         */
1021                        if (remove_empty_directories(git_path("logs/%s", newref))) {
1022                                error("Directory not empty: logs/%s", newref);
1023                                goto rollback;
1024                        }
1025                        goto retry;
1026                } else {
1027                        error("unable to move logfile tmp-renamed-log to logs/%s: %s",
1028                                newref, strerror(errno));
1029                        goto rollback;
1030                }
1031        }
1032        logmoved = log;
1033
1034        lock = lock_ref_sha1_basic(newref, NULL, 0, NULL);
1035        if (!lock) {
1036                error("unable to lock %s for update", newref);
1037                goto rollback;
1038        }
1039
1040        lock->force_write = 1;
1041        hashcpy(lock->old_sha1, orig_sha1);
1042        if (write_ref_sha1(lock, orig_sha1, logmsg)) {
1043                error("unable to write current sha1 into %s", newref);
1044                goto rollback;
1045        }
1046
1047        return 0;
1048
1049 rollback:
1050        lock = lock_ref_sha1_basic(oldref, NULL, 0, NULL);
1051        if (!lock) {
1052                error("unable to lock %s for rollback", oldref);
1053                goto rollbacklog;
1054        }
1055
1056        lock->force_write = 1;
1057        flag = log_all_ref_updates;
1058        log_all_ref_updates = 0;
1059        if (write_ref_sha1(lock, orig_sha1, NULL))
1060                error("unable to write current sha1 into %s", oldref);
1061        log_all_ref_updates = flag;
1062
1063 rollbacklog:
1064        if (logmoved && rename(git_path("logs/%s", newref), git_path("logs/%s", oldref)))
1065                error("unable to restore logfile %s from %s: %s",
1066                        oldref, newref, strerror(errno));
1067        if (!logmoved && log &&
1068            rename(git_path("tmp-renamed-log"), git_path("logs/%s", oldref)))
1069                error("unable to restore logfile %s from tmp-renamed-log: %s",
1070                        oldref, strerror(errno));
1071
1072        return 1;
1073}
1074
1075int close_ref(struct ref_lock *lock)
1076{
1077        if (close_lock_file(lock->lk))
1078                return -1;
1079        lock->lock_fd = -1;
1080        return 0;
1081}
1082
1083int commit_ref(struct ref_lock *lock)
1084{
1085        if (commit_lock_file(lock->lk))
1086                return -1;
1087        lock->lock_fd = -1;
1088        return 0;
1089}
1090
1091void unlock_ref(struct ref_lock *lock)
1092{
1093        /* Do not free lock->lk -- atexit() still looks at them */
1094        if (lock->lk)
1095                rollback_lock_file(lock->lk);
1096        free(lock->ref_name);
1097        free(lock->orig_ref_name);
1098        free(lock);
1099}
1100
1101/*
1102 * copy the reflog message msg to buf, which has been allocated sufficiently
1103 * large, while cleaning up the whitespaces.  Especially, convert LF to space,
1104 * because reflog file is one line per entry.
1105 */
1106static int copy_msg(char *buf, const char *msg)
1107{
1108        char *cp = buf;
1109        char c;
1110        int wasspace = 1;
1111
1112        *cp++ = '\t';
1113        while ((c = *msg++)) {
1114                if (wasspace && isspace(c))
1115                        continue;
1116                wasspace = isspace(c);
1117                if (wasspace)
1118                        c = ' ';
1119                *cp++ = c;
1120        }
1121        while (buf < cp && isspace(cp[-1]))
1122                cp--;
1123        *cp++ = '\n';
1124        return cp - buf;
1125}
1126
1127static int log_ref_write(const char *ref_name, const unsigned char *old_sha1,
1128                         const unsigned char *new_sha1, const char *msg)
1129{
1130        int logfd, written, oflags = O_APPEND | O_WRONLY;
1131        unsigned maxlen, len;
1132        int msglen;
1133        char *log_file, *logrec;
1134        const char *committer;
1135
1136        if (log_all_ref_updates < 0)
1137                log_all_ref_updates = !is_bare_repository();
1138
1139        log_file = git_path("logs/%s", ref_name);
1140
1141        if (log_all_ref_updates &&
1142            (!prefixcmp(ref_name, "refs/heads/") ||
1143             !prefixcmp(ref_name, "refs/remotes/") ||
1144             !strcmp(ref_name, "HEAD"))) {
1145                if (safe_create_leading_directories(log_file) < 0)
1146                        return error("unable to create directory for %s",
1147                                     log_file);
1148                oflags |= O_CREAT;
1149        }
1150
1151        logfd = open(log_file, oflags, 0666);
1152        if (logfd < 0) {
1153                if (!(oflags & O_CREAT) && errno == ENOENT)
1154                        return 0;
1155
1156                if ((oflags & O_CREAT) && errno == EISDIR) {
1157                        if (remove_empty_directories(log_file)) {
1158                                return error("There are still logs under '%s'",
1159                                             log_file);
1160                        }
1161                        logfd = open(log_file, oflags, 0666);
1162                }
1163
1164                if (logfd < 0)
1165                        return error("Unable to append to %s: %s",
1166                                     log_file, strerror(errno));
1167        }
1168
1169        adjust_shared_perm(log_file);
1170
1171        msglen = msg ? strlen(msg) : 0;
1172        committer = git_committer_info(0);
1173        maxlen = strlen(committer) + msglen + 100;
1174        logrec = xmalloc(maxlen);
1175        len = sprintf(logrec, "%s %s %s\n",
1176                      sha1_to_hex(old_sha1),
1177                      sha1_to_hex(new_sha1),
1178                      committer);
1179        if (msglen)
1180                len += copy_msg(logrec + len - 1, msg) - 1;
1181        written = len <= maxlen ? write_in_full(logfd, logrec, len) : -1;
1182        free(logrec);
1183        if (close(logfd) != 0 || written != len)
1184                return error("Unable to append to %s", log_file);
1185        return 0;
1186}
1187
1188static int is_branch(const char *refname)
1189{
1190        return !strcmp(refname, "HEAD") || !prefixcmp(refname, "refs/heads/");
1191}
1192
1193int write_ref_sha1(struct ref_lock *lock,
1194        const unsigned char *sha1, const char *logmsg)
1195{
1196        static char term = '\n';
1197        struct object *o;
1198
1199        if (!lock)
1200                return -1;
1201        if (!lock->force_write && !hashcmp(lock->old_sha1, sha1)) {
1202                unlock_ref(lock);
1203                return 0;
1204        }
1205        o = parse_object(sha1);
1206        if (!o) {
1207                error("Trying to write ref %s with nonexistant object %s",
1208                        lock->ref_name, sha1_to_hex(sha1));
1209                unlock_ref(lock);
1210                return -1;
1211        }
1212        if (o->type != OBJ_COMMIT && is_branch(lock->ref_name)) {
1213                error("Trying to write non-commit object %s to branch %s",
1214                        sha1_to_hex(sha1), lock->ref_name);
1215                unlock_ref(lock);
1216                return -1;
1217        }
1218        if (write_in_full(lock->lock_fd, sha1_to_hex(sha1), 40) != 40 ||
1219            write_in_full(lock->lock_fd, &term, 1) != 1
1220                || close_ref(lock) < 0) {
1221                error("Couldn't write %s", lock->lk->filename);
1222                unlock_ref(lock);
1223                return -1;
1224        }
1225        invalidate_cached_refs();
1226        if (log_ref_write(lock->ref_name, lock->old_sha1, sha1, logmsg) < 0 ||
1227            (strcmp(lock->ref_name, lock->orig_ref_name) &&
1228             log_ref_write(lock->orig_ref_name, lock->old_sha1, sha1, logmsg) < 0)) {
1229                unlock_ref(lock);
1230                return -1;
1231        }
1232        if (strcmp(lock->orig_ref_name, "HEAD") != 0) {
1233                /*
1234                 * Special hack: If a branch is updated directly and HEAD
1235                 * points to it (may happen on the remote side of a push
1236                 * for example) then logically the HEAD reflog should be
1237                 * updated too.
1238                 * A generic solution implies reverse symref information,
1239                 * but finding all symrefs pointing to the given branch
1240                 * would be rather costly for this rare event (the direct
1241                 * update of a branch) to be worth it.  So let's cheat and
1242                 * check with HEAD only which should cover 99% of all usage
1243                 * scenarios (even 100% of the default ones).
1244                 */
1245                unsigned char head_sha1[20];
1246                int head_flag;
1247                const char *head_ref;
1248                head_ref = resolve_ref("HEAD", head_sha1, 1, &head_flag);
1249                if (head_ref && (head_flag & REF_ISSYMREF) &&
1250                    !strcmp(head_ref, lock->ref_name))
1251                        log_ref_write("HEAD", lock->old_sha1, sha1, logmsg);
1252        }
1253        if (commit_ref(lock)) {
1254                error("Couldn't set %s", lock->ref_name);
1255                unlock_ref(lock);
1256                return -1;
1257        }
1258        unlock_ref(lock);
1259        return 0;
1260}
1261
1262int create_symref(const char *ref_target, const char *refs_heads_master,
1263                  const char *logmsg)
1264{
1265        const char *lockpath;
1266        char ref[1000];
1267        int fd, len, written;
1268        char *git_HEAD = xstrdup(git_path("%s", ref_target));
1269        unsigned char old_sha1[20], new_sha1[20];
1270
1271        if (logmsg && read_ref(ref_target, old_sha1))
1272                hashclr(old_sha1);
1273
1274        if (safe_create_leading_directories(git_HEAD) < 0)
1275                return error("unable to create directory for %s", git_HEAD);
1276
1277#ifndef NO_SYMLINK_HEAD
1278        if (prefer_symlink_refs) {
1279                unlink(git_HEAD);
1280                if (!symlink(refs_heads_master, git_HEAD))
1281                        goto done;
1282                fprintf(stderr, "no symlink - falling back to symbolic ref\n");
1283        }
1284#endif
1285
1286        len = snprintf(ref, sizeof(ref), "ref: %s\n", refs_heads_master);
1287        if (sizeof(ref) <= len) {
1288                error("refname too long: %s", refs_heads_master);
1289                goto error_free_return;
1290        }
1291        lockpath = mkpath("%s.lock", git_HEAD);
1292        fd = open(lockpath, O_CREAT | O_EXCL | O_WRONLY, 0666);
1293        if (fd < 0) {
1294                error("Unable to open %s for writing", lockpath);
1295                goto error_free_return;
1296        }
1297        written = write_in_full(fd, ref, len);
1298        if (close(fd) != 0 || written != len) {
1299                error("Unable to write to %s", lockpath);
1300                goto error_unlink_return;
1301        }
1302        if (rename(lockpath, git_HEAD) < 0) {
1303                error("Unable to create %s", git_HEAD);
1304                goto error_unlink_return;
1305        }
1306        if (adjust_shared_perm(git_HEAD)) {
1307                error("Unable to fix permissions on %s", lockpath);
1308        error_unlink_return:
1309                unlink(lockpath);
1310        error_free_return:
1311                free(git_HEAD);
1312                return -1;
1313        }
1314
1315#ifndef NO_SYMLINK_HEAD
1316        done:
1317#endif
1318        if (logmsg && !read_ref(refs_heads_master, new_sha1))
1319                log_ref_write(ref_target, old_sha1, new_sha1, logmsg);
1320
1321        free(git_HEAD);
1322        return 0;
1323}
1324
1325static char *ref_msg(const char *line, const char *endp)
1326{
1327        const char *ep;
1328        line += 82;
1329        ep = memchr(line, '\n', endp - line);
1330        if (!ep)
1331                ep = endp;
1332        return xmemdupz(line, ep - line);
1333}
1334
1335int 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)
1336{
1337        const char *logfile, *logdata, *logend, *rec, *lastgt, *lastrec;
1338        char *tz_c;
1339        int logfd, tz, reccnt = 0;
1340        struct stat st;
1341        unsigned long date;
1342        unsigned char logged_sha1[20];
1343        void *log_mapped;
1344        size_t mapsz;
1345
1346        logfile = git_path("logs/%s", ref);
1347        logfd = open(logfile, O_RDONLY, 0);
1348        if (logfd < 0)
1349                die("Unable to read log %s: %s", logfile, strerror(errno));
1350        fstat(logfd, &st);
1351        if (!st.st_size)
1352                die("Log %s is empty.", logfile);
1353        mapsz = xsize_t(st.st_size);
1354        log_mapped = xmmap(NULL, mapsz, PROT_READ, MAP_PRIVATE, logfd, 0);
1355        logdata = log_mapped;
1356        close(logfd);
1357
1358        lastrec = NULL;
1359        rec = logend = logdata + st.st_size;
1360        while (logdata < rec) {
1361                reccnt++;
1362                if (logdata < rec && *(rec-1) == '\n')
1363                        rec--;
1364                lastgt = NULL;
1365                while (logdata < rec && *(rec-1) != '\n') {
1366                        rec--;
1367                        if (*rec == '>')
1368                                lastgt = rec;
1369                }
1370                if (!lastgt)
1371                        die("Log %s is corrupt.", logfile);
1372                date = strtoul(lastgt + 1, &tz_c, 10);
1373                if (date <= at_time || cnt == 0) {
1374                        tz = strtoul(tz_c, NULL, 10);
1375                        if (msg)
1376                                *msg = ref_msg(rec, logend);
1377                        if (cutoff_time)
1378                                *cutoff_time = date;
1379                        if (cutoff_tz)
1380                                *cutoff_tz = tz;
1381                        if (cutoff_cnt)
1382                                *cutoff_cnt = reccnt - 1;
1383                        if (lastrec) {
1384                                if (get_sha1_hex(lastrec, logged_sha1))
1385                                        die("Log %s is corrupt.", logfile);
1386                                if (get_sha1_hex(rec + 41, sha1))
1387                                        die("Log %s is corrupt.", logfile);
1388                                if (hashcmp(logged_sha1, sha1)) {
1389                                        fprintf(stderr,
1390                                                "warning: Log %s has gap after %s.\n",
1391                                                logfile, show_date(date, tz, DATE_RFC2822));
1392                                }
1393                        }
1394                        else if (date == at_time) {
1395                                if (get_sha1_hex(rec + 41, sha1))
1396                                        die("Log %s is corrupt.", logfile);
1397                        }
1398                        else {
1399                                if (get_sha1_hex(rec + 41, logged_sha1))
1400                                        die("Log %s is corrupt.", logfile);
1401                                if (hashcmp(logged_sha1, sha1)) {
1402                                        fprintf(stderr,
1403                                                "warning: Log %s unexpectedly ended on %s.\n",
1404                                                logfile, show_date(date, tz, DATE_RFC2822));
1405                                }
1406                        }
1407                        munmap(log_mapped, mapsz);
1408                        return 0;
1409                }
1410                lastrec = rec;
1411                if (cnt > 0)
1412                        cnt--;
1413        }
1414
1415        rec = logdata;
1416        while (rec < logend && *rec != '>' && *rec != '\n')
1417                rec++;
1418        if (rec == logend || *rec == '\n')
1419                die("Log %s is corrupt.", logfile);
1420        date = strtoul(rec + 1, &tz_c, 10);
1421        tz = strtoul(tz_c, NULL, 10);
1422        if (get_sha1_hex(logdata, sha1))
1423                die("Log %s is corrupt.", logfile);
1424        if (is_null_sha1(sha1)) {
1425                if (get_sha1_hex(logdata + 41, sha1))
1426                        die("Log %s is corrupt.", logfile);
1427        }
1428        if (msg)
1429                *msg = ref_msg(logdata, logend);
1430        munmap(log_mapped, mapsz);
1431
1432        if (cutoff_time)
1433                *cutoff_time = date;
1434        if (cutoff_tz)
1435                *cutoff_tz = tz;
1436        if (cutoff_cnt)
1437                *cutoff_cnt = reccnt;
1438        return 1;
1439}
1440
1441int for_each_reflog_ent(const char *ref, each_reflog_ent_fn fn, void *cb_data)
1442{
1443        const char *logfile;
1444        FILE *logfp;
1445        char buf[1024];
1446        int ret = 0;
1447
1448        logfile = git_path("logs/%s", ref);
1449        logfp = fopen(logfile, "r");
1450        if (!logfp)
1451                return -1;
1452        while (fgets(buf, sizeof(buf), logfp)) {
1453                unsigned char osha1[20], nsha1[20];
1454                char *email_end, *message;
1455                unsigned long timestamp;
1456                int len, tz;
1457
1458                /* old SP new SP name <email> SP time TAB msg LF */
1459                len = strlen(buf);
1460                if (len < 83 || buf[len-1] != '\n' ||
1461                    get_sha1_hex(buf, osha1) || buf[40] != ' ' ||
1462                    get_sha1_hex(buf + 41, nsha1) || buf[81] != ' ' ||
1463                    !(email_end = strchr(buf + 82, '>')) ||
1464                    email_end[1] != ' ' ||
1465                    !(timestamp = strtoul(email_end + 2, &message, 10)) ||
1466                    !message || message[0] != ' ' ||
1467                    (message[1] != '+' && message[1] != '-') ||
1468                    !isdigit(message[2]) || !isdigit(message[3]) ||
1469                    !isdigit(message[4]) || !isdigit(message[5]))
1470                        continue; /* corrupt? */
1471                email_end[1] = '\0';
1472                tz = strtol(message + 1, NULL, 10);
1473                if (message[6] != '\t')
1474                        message += 6;
1475                else
1476                        message += 7;
1477                ret = fn(osha1, nsha1, buf+82, timestamp, tz, message, cb_data);
1478                if (ret)
1479                        break;
1480        }
1481        fclose(logfp);
1482        return ret;
1483}
1484
1485static int do_for_each_reflog(const char *base, each_ref_fn fn, void *cb_data)
1486{
1487        DIR *dir = opendir(git_path("logs/%s", base));
1488        int retval = 0;
1489
1490        if (dir) {
1491                struct dirent *de;
1492                int baselen = strlen(base);
1493                char *log = xmalloc(baselen + 257);
1494
1495                memcpy(log, base, baselen);
1496                if (baselen && base[baselen-1] != '/')
1497                        log[baselen++] = '/';
1498
1499                while ((de = readdir(dir)) != NULL) {
1500                        struct stat st;
1501                        int namelen;
1502
1503                        if (de->d_name[0] == '.')
1504                                continue;
1505                        namelen = strlen(de->d_name);
1506                        if (namelen > 255)
1507                                continue;
1508                        if (has_extension(de->d_name, ".lock"))
1509                                continue;
1510                        memcpy(log + baselen, de->d_name, namelen+1);
1511                        if (stat(git_path("logs/%s", log), &st) < 0)
1512                                continue;
1513                        if (S_ISDIR(st.st_mode)) {
1514                                retval = do_for_each_reflog(log, fn, cb_data);
1515                        } else {
1516                                unsigned char sha1[20];
1517                                if (!resolve_ref(log, sha1, 0, NULL))
1518                                        retval = error("bad ref for %s", log);
1519                                else
1520                                        retval = fn(log, sha1, 0, cb_data);
1521                        }
1522                        if (retval)
1523                                break;
1524                }
1525                free(log);
1526                closedir(dir);
1527        }
1528        else if (*base)
1529                return errno;
1530        return retval;
1531}
1532
1533int for_each_reflog(each_ref_fn fn, void *cb_data)
1534{
1535        return do_for_each_reflog("", fn, cb_data);
1536}
1537
1538int update_ref(const char *action, const char *refname,
1539                const unsigned char *sha1, const unsigned char *oldval,
1540                int flags, enum action_on_err onerr)
1541{
1542        static struct ref_lock *lock;
1543        lock = lock_any_ref_for_update(refname, oldval, flags);
1544        if (!lock) {
1545                const char *str = "Cannot lock the ref '%s'.";
1546                switch (onerr) {
1547                case MSG_ON_ERR: error(str, refname); break;
1548                case DIE_ON_ERR: die(str, refname); break;
1549                case QUIET_ON_ERR: break;
1550                }
1551                return 1;
1552        }
1553        if (write_ref_sha1(lock, sha1, action) < 0) {
1554                const char *str = "Cannot update the ref '%s'.";
1555                switch (onerr) {
1556                case MSG_ON_ERR: error(str, refname); break;
1557                case DIE_ON_ERR: die(str, refname); break;
1558                case QUIET_ON_ERR: break;
1559                }
1560                return 1;
1561        }
1562        return 0;
1563}
1564
1565struct ref *find_ref_by_name(struct ref *list, const char *name)
1566{
1567        for ( ; list; list = list->next)
1568                if (!strcmp(list->name, name))
1569                        return list;
1570        return NULL;
1571}