34fff75b0d2062b7c7445864fe9f9d70962b1bee
   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                                hashclr(sha1);
 280                        list = add_ref(ref, sha1, flag, list, NULL);
 281                }
 282                free(ref);
 283                closedir(dir);
 284        }
 285        return sort_ref_list(list);
 286}
 287
 288struct warn_if_dangling_data {
 289        FILE *fp;
 290        const char *refname;
 291        const char *msg_fmt;
 292};
 293
 294static int warn_if_dangling_symref(const char *refname, const unsigned char *sha1,
 295                                   int flags, void *cb_data)
 296{
 297        struct warn_if_dangling_data *d = cb_data;
 298        const char *resolves_to;
 299        unsigned char junk[20];
 300
 301        if (!(flags & REF_ISSYMREF))
 302                return 0;
 303
 304        resolves_to = resolve_ref(refname, junk, 0, NULL);
 305        if (!resolves_to || strcmp(resolves_to, d->refname))
 306                return 0;
 307
 308        fprintf(d->fp, d->msg_fmt, refname);
 309        return 0;
 310}
 311
 312void warn_dangling_symref(FILE *fp, const char *msg_fmt, const char *refname)
 313{
 314        struct warn_if_dangling_data data = { fp, refname, msg_fmt };
 315        for_each_rawref(warn_if_dangling_symref, &data);
 316}
 317
 318static struct ref_list *get_loose_refs(void)
 319{
 320        if (!cached_refs.did_loose) {
 321                cached_refs.loose = get_ref_dir("refs", NULL);
 322                cached_refs.did_loose = 1;
 323        }
 324        return cached_refs.loose;
 325}
 326
 327/* We allow "recursive" symbolic refs. Only within reason, though */
 328#define MAXDEPTH 5
 329#define MAXREFLEN (1024)
 330
 331static int resolve_gitlink_packed_ref(char *name, int pathlen, const char *refname, unsigned char *result)
 332{
 333        FILE *f;
 334        struct cached_refs refs;
 335        struct ref_list *ref;
 336        int retval;
 337
 338        strcpy(name + pathlen, "packed-refs");
 339        f = fopen(name, "r");
 340        if (!f)
 341                return -1;
 342        read_packed_refs(f, &refs);
 343        fclose(f);
 344        ref = refs.packed;
 345        retval = -1;
 346        while (ref) {
 347                if (!strcmp(ref->name, refname)) {
 348                        retval = 0;
 349                        memcpy(result, ref->sha1, 20);
 350                        break;
 351                }
 352                ref = ref->next;
 353        }
 354        free_ref_list(refs.packed);
 355        return retval;
 356}
 357
 358static int resolve_gitlink_ref_recursive(char *name, int pathlen, const char *refname, unsigned char *result, int recursion)
 359{
 360        int fd, len = strlen(refname);
 361        char buffer[128], *p;
 362
 363        if (recursion > MAXDEPTH || len > MAXREFLEN)
 364                return -1;
 365        memcpy(name + pathlen, refname, len+1);
 366        fd = open(name, O_RDONLY);
 367        if (fd < 0)
 368                return resolve_gitlink_packed_ref(name, pathlen, refname, result);
 369
 370        len = read(fd, buffer, sizeof(buffer)-1);
 371        close(fd);
 372        if (len < 0)
 373                return -1;
 374        while (len && isspace(buffer[len-1]))
 375                len--;
 376        buffer[len] = 0;
 377
 378        /* Was it a detached head or an old-fashioned symlink? */
 379        if (!get_sha1_hex(buffer, result))
 380                return 0;
 381
 382        /* Symref? */
 383        if (strncmp(buffer, "ref:", 4))
 384                return -1;
 385        p = buffer + 4;
 386        while (isspace(*p))
 387                p++;
 388
 389        return resolve_gitlink_ref_recursive(name, pathlen, p, result, recursion+1);
 390}
 391
 392int resolve_gitlink_ref(const char *path, const char *refname, unsigned char *result)
 393{
 394        int len = strlen(path), retval;
 395        char *gitdir;
 396        const char *tmp;
 397
 398        while (len && path[len-1] == '/')
 399                len--;
 400        if (!len)
 401                return -1;
 402        gitdir = xmalloc(len + MAXREFLEN + 8);
 403        memcpy(gitdir, path, len);
 404        memcpy(gitdir + len, "/.git", 6);
 405        len += 5;
 406
 407        tmp = read_gitfile_gently(gitdir);
 408        if (tmp) {
 409                free(gitdir);
 410                len = strlen(tmp);
 411                gitdir = xmalloc(len + MAXREFLEN + 3);
 412                memcpy(gitdir, tmp, len);
 413        }
 414        gitdir[len] = '/';
 415        gitdir[++len] = '\0';
 416        retval = resolve_gitlink_ref_recursive(gitdir, len, refname, result, 0);
 417        free(gitdir);
 418        return retval;
 419}
 420
 421/*
 422 * If the "reading" argument is set, this function finds out what _object_
 423 * the ref points at by "reading" the ref.  The ref, if it is not symbolic,
 424 * has to exist, and if it is symbolic, it has to point at an existing ref,
 425 * because the "read" goes through the symref to the ref it points at.
 426 *
 427 * The access that is not "reading" may often be "writing", but does not
 428 * have to; it can be merely checking _where it leads to_. If it is a
 429 * prelude to "writing" to the ref, a write to a symref that points at
 430 * yet-to-be-born ref will create the real ref pointed by the symref.
 431 * reading=0 allows the caller to check where such a symref leads to.
 432 */
 433const char *resolve_ref(const char *ref, unsigned char *sha1, int reading, int *flag)
 434{
 435        int depth = MAXDEPTH;
 436        ssize_t len;
 437        char buffer[256];
 438        static char ref_buffer[256];
 439
 440        if (flag)
 441                *flag = 0;
 442
 443        for (;;) {
 444                char path[PATH_MAX];
 445                struct stat st;
 446                char *buf;
 447                int fd;
 448
 449                if (--depth < 0)
 450                        return NULL;
 451
 452                git_snpath(path, sizeof(path), "%s", ref);
 453                /* Special case: non-existing file. */
 454                if (lstat(path, &st) < 0) {
 455                        struct ref_list *list = get_packed_refs();
 456                        while (list) {
 457                                if (!strcmp(ref, list->name)) {
 458                                        hashcpy(sha1, list->sha1);
 459                                        if (flag)
 460                                                *flag |= REF_ISPACKED;
 461                                        return ref;
 462                                }
 463                                list = list->next;
 464                        }
 465                        if (reading || errno != ENOENT)
 466                                return NULL;
 467                        hashclr(sha1);
 468                        return ref;
 469                }
 470
 471                /* Follow "normalized" - ie "refs/.." symlinks by hand */
 472                if (S_ISLNK(st.st_mode)) {
 473                        len = readlink(path, buffer, sizeof(buffer)-1);
 474                        if (len >= 5 && !memcmp("refs/", buffer, 5)) {
 475                                buffer[len] = 0;
 476                                strcpy(ref_buffer, buffer);
 477                                ref = ref_buffer;
 478                                if (flag)
 479                                        *flag |= REF_ISSYMREF;
 480                                continue;
 481                        }
 482                }
 483
 484                /* Is it a directory? */
 485                if (S_ISDIR(st.st_mode)) {
 486                        errno = EISDIR;
 487                        return NULL;
 488                }
 489
 490                /*
 491                 * Anything else, just open it and try to use it as
 492                 * a ref
 493                 */
 494                fd = open(path, O_RDONLY);
 495                if (fd < 0)
 496                        return NULL;
 497                len = read_in_full(fd, buffer, sizeof(buffer)-1);
 498                close(fd);
 499
 500                /*
 501                 * Is it a symbolic ref?
 502                 */
 503                if (len < 4 || memcmp("ref:", buffer, 4))
 504                        break;
 505                buf = buffer + 4;
 506                len -= 4;
 507                while (len && isspace(*buf))
 508                        buf++, len--;
 509                while (len && isspace(buf[len-1]))
 510                        len--;
 511                buf[len] = 0;
 512                memcpy(ref_buffer, buf, len + 1);
 513                ref = ref_buffer;
 514                if (flag)
 515                        *flag |= REF_ISSYMREF;
 516        }
 517        if (len < 40 || get_sha1_hex(buffer, sha1))
 518                return NULL;
 519        return ref;
 520}
 521
 522/* The argument to filter_refs */
 523struct ref_filter {
 524        const char *pattern;
 525        each_ref_fn *fn;
 526        void *cb_data;
 527};
 528
 529int read_ref(const char *ref, unsigned char *sha1)
 530{
 531        if (resolve_ref(ref, sha1, 1, NULL))
 532                return 0;
 533        return -1;
 534}
 535
 536#define DO_FOR_EACH_INCLUDE_BROKEN 01
 537static int do_one_ref(const char *base, each_ref_fn fn, int trim,
 538                      int flags, void *cb_data, struct ref_list *entry)
 539{
 540        if (strncmp(base, entry->name, trim))
 541                return 0;
 542        /* Is this a "negative ref" that represents a deleted ref? */
 543        if (is_null_sha1(entry->sha1))
 544                return 0;
 545        if (!(flags & DO_FOR_EACH_INCLUDE_BROKEN)) {
 546                if (!has_sha1_file(entry->sha1)) {
 547                        error("%s does not point to a valid object!", entry->name);
 548                        return 0;
 549                }
 550        }
 551        current_ref = entry;
 552        return fn(entry->name + trim, entry->sha1, entry->flag, cb_data);
 553}
 554
 555static int filter_refs(const char *ref, const unsigned char *sha, int flags,
 556        void *data)
 557{
 558        struct ref_filter *filter = (struct ref_filter *)data;
 559        if (fnmatch(filter->pattern, ref, 0))
 560                return 0;
 561        return filter->fn(ref, sha, flags, filter->cb_data);
 562}
 563
 564int peel_ref(const char *ref, unsigned char *sha1)
 565{
 566        int flag;
 567        unsigned char base[20];
 568        struct object *o;
 569
 570        if (current_ref && (current_ref->name == ref
 571                || !strcmp(current_ref->name, ref))) {
 572                if (current_ref->flag & REF_KNOWS_PEELED) {
 573                        hashcpy(sha1, current_ref->peeled);
 574                        return 0;
 575                }
 576                hashcpy(base, current_ref->sha1);
 577                goto fallback;
 578        }
 579
 580        if (!resolve_ref(ref, base, 1, &flag))
 581                return -1;
 582
 583        if ((flag & REF_ISPACKED)) {
 584                struct ref_list *list = get_packed_refs();
 585
 586                while (list) {
 587                        if (!strcmp(list->name, ref)) {
 588                                if (list->flag & REF_KNOWS_PEELED) {
 589                                        hashcpy(sha1, list->peeled);
 590                                        return 0;
 591                                }
 592                                /* older pack-refs did not leave peeled ones */
 593                                break;
 594                        }
 595                        list = list->next;
 596                }
 597        }
 598
 599fallback:
 600        o = parse_object(base);
 601        if (o && o->type == OBJ_TAG) {
 602                o = deref_tag(o, ref, 0);
 603                if (o) {
 604                        hashcpy(sha1, o->sha1);
 605                        return 0;
 606                }
 607        }
 608        return -1;
 609}
 610
 611static int do_for_each_ref(const char *base, each_ref_fn fn, int trim,
 612                           int flags, void *cb_data)
 613{
 614        int retval = 0;
 615        struct ref_list *packed = get_packed_refs();
 616        struct ref_list *loose = get_loose_refs();
 617
 618        struct ref_list *extra;
 619
 620        for (extra = extra_refs; extra; extra = extra->next)
 621                retval = do_one_ref(base, fn, trim, flags, cb_data, extra);
 622
 623        while (packed && loose) {
 624                struct ref_list *entry;
 625                int cmp = strcmp(packed->name, loose->name);
 626                if (!cmp) {
 627                        packed = packed->next;
 628                        continue;
 629                }
 630                if (cmp > 0) {
 631                        entry = loose;
 632                        loose = loose->next;
 633                } else {
 634                        entry = packed;
 635                        packed = packed->next;
 636                }
 637                retval = do_one_ref(base, fn, trim, flags, cb_data, entry);
 638                if (retval)
 639                        goto end_each;
 640        }
 641
 642        for (packed = packed ? packed : loose; packed; packed = packed->next) {
 643                retval = do_one_ref(base, fn, trim, flags, cb_data, packed);
 644                if (retval)
 645                        goto end_each;
 646        }
 647
 648end_each:
 649        current_ref = NULL;
 650        return retval;
 651}
 652
 653int head_ref(each_ref_fn fn, void *cb_data)
 654{
 655        unsigned char sha1[20];
 656        int flag;
 657
 658        if (resolve_ref("HEAD", sha1, 1, &flag))
 659                return fn("HEAD", sha1, flag, cb_data);
 660        return 0;
 661}
 662
 663int for_each_ref(each_ref_fn fn, void *cb_data)
 664{
 665        return do_for_each_ref("refs/", fn, 0, 0, cb_data);
 666}
 667
 668int for_each_ref_in(const char *prefix, each_ref_fn fn, void *cb_data)
 669{
 670        return do_for_each_ref(prefix, fn, strlen(prefix), 0, cb_data);
 671}
 672
 673int for_each_tag_ref(each_ref_fn fn, void *cb_data)
 674{
 675        return for_each_ref_in("refs/tags/", fn, cb_data);
 676}
 677
 678int for_each_branch_ref(each_ref_fn fn, void *cb_data)
 679{
 680        return for_each_ref_in("refs/heads/", fn, cb_data);
 681}
 682
 683int for_each_remote_ref(each_ref_fn fn, void *cb_data)
 684{
 685        return for_each_ref_in("refs/remotes/", fn, cb_data);
 686}
 687
 688int for_each_replace_ref(each_ref_fn fn, void *cb_data)
 689{
 690        return do_for_each_ref("refs/replace/", fn, 13, 0, cb_data);
 691}
 692
 693int for_each_glob_ref(each_ref_fn fn, const char *pattern, void *cb_data)
 694{
 695        struct strbuf real_pattern = STRBUF_INIT;
 696        struct ref_filter filter;
 697        const char *has_glob_specials;
 698        int ret;
 699
 700        if (prefixcmp(pattern, "refs/"))
 701                strbuf_addstr(&real_pattern, "refs/");
 702        strbuf_addstr(&real_pattern, pattern);
 703
 704        has_glob_specials = strpbrk(pattern, "?*[");
 705        if (!has_glob_specials) {
 706                /* Append impiled '/' '*' if not present. */
 707                if (real_pattern.buf[real_pattern.len - 1] != '/')
 708                        strbuf_addch(&real_pattern, '/');
 709                /* No need to check for '*', there is none. */
 710                strbuf_addch(&real_pattern, '*');
 711        }
 712
 713        filter.pattern = real_pattern.buf;
 714        filter.fn = fn;
 715        filter.cb_data = cb_data;
 716        ret = for_each_ref(filter_refs, &filter);
 717
 718        strbuf_release(&real_pattern);
 719        return ret;
 720}
 721
 722int for_each_rawref(each_ref_fn fn, void *cb_data)
 723{
 724        return do_for_each_ref("refs/", fn, 0,
 725                               DO_FOR_EACH_INCLUDE_BROKEN, cb_data);
 726}
 727
 728/*
 729 * Make sure "ref" is something reasonable to have under ".git/refs/";
 730 * We do not like it if:
 731 *
 732 * - any path component of it begins with ".", or
 733 * - it has double dots "..", or
 734 * - it has ASCII control character, "~", "^", ":" or SP, anywhere, or
 735 * - it ends with a "/".
 736 * - it ends with ".lock"
 737 * - it contains a "\" (backslash)
 738 */
 739
 740static inline int bad_ref_char(int ch)
 741{
 742        if (((unsigned) ch) <= ' ' ||
 743            ch == '~' || ch == '^' || ch == ':' || ch == '\\')
 744                return 1;
 745        /* 2.13 Pattern Matching Notation */
 746        if (ch == '?' || ch == '[') /* Unsupported */
 747                return 1;
 748        if (ch == '*') /* Supported at the end */
 749                return 2;
 750        return 0;
 751}
 752
 753int check_ref_format(const char *ref)
 754{
 755        int ch, level, bad_type, last;
 756        int ret = CHECK_REF_FORMAT_OK;
 757        const char *cp = ref;
 758
 759        level = 0;
 760        while (1) {
 761                while ((ch = *cp++) == '/')
 762                        ; /* tolerate duplicated slashes */
 763                if (!ch)
 764                        /* should not end with slashes */
 765                        return CHECK_REF_FORMAT_ERROR;
 766
 767                /* we are at the beginning of the path component */
 768                if (ch == '.')
 769                        return CHECK_REF_FORMAT_ERROR;
 770                bad_type = bad_ref_char(ch);
 771                if (bad_type) {
 772                        if (bad_type == 2 && (!*cp || *cp == '/') &&
 773                            ret == CHECK_REF_FORMAT_OK)
 774                                ret = CHECK_REF_FORMAT_WILDCARD;
 775                        else
 776                                return CHECK_REF_FORMAT_ERROR;
 777                }
 778
 779                last = ch;
 780                /* scan the rest of the path component */
 781                while ((ch = *cp++) != 0) {
 782                        bad_type = bad_ref_char(ch);
 783                        if (bad_type)
 784                                return CHECK_REF_FORMAT_ERROR;
 785                        if (ch == '/')
 786                                break;
 787                        if (last == '.' && ch == '.')
 788                                return CHECK_REF_FORMAT_ERROR;
 789                        if (last == '@' && ch == '{')
 790                                return CHECK_REF_FORMAT_ERROR;
 791                        last = ch;
 792                }
 793                level++;
 794                if (!ch) {
 795                        if (ref <= cp - 2 && cp[-2] == '.')
 796                                return CHECK_REF_FORMAT_ERROR;
 797                        if (level < 2)
 798                                return CHECK_REF_FORMAT_ONELEVEL;
 799                        if (has_extension(ref, ".lock"))
 800                                return CHECK_REF_FORMAT_ERROR;
 801                        return ret;
 802                }
 803        }
 804}
 805
 806const char *prettify_refname(const char *name)
 807{
 808        return name + (
 809                !prefixcmp(name, "refs/heads/") ? 11 :
 810                !prefixcmp(name, "refs/tags/") ? 10 :
 811                !prefixcmp(name, "refs/remotes/") ? 13 :
 812                0);
 813}
 814
 815const char *ref_rev_parse_rules[] = {
 816        "%.*s",
 817        "refs/%.*s",
 818        "refs/tags/%.*s",
 819        "refs/heads/%.*s",
 820        "refs/remotes/%.*s",
 821        "refs/remotes/%.*s/HEAD",
 822        NULL
 823};
 824
 825const char *ref_fetch_rules[] = {
 826        "%.*s",
 827        "refs/%.*s",
 828        "refs/heads/%.*s",
 829        NULL
 830};
 831
 832int refname_match(const char *abbrev_name, const char *full_name, const char **rules)
 833{
 834        const char **p;
 835        const int abbrev_name_len = strlen(abbrev_name);
 836
 837        for (p = rules; *p; p++) {
 838                if (!strcmp(full_name, mkpath(*p, abbrev_name_len, abbrev_name))) {
 839                        return 1;
 840                }
 841        }
 842
 843        return 0;
 844}
 845
 846static struct ref_lock *verify_lock(struct ref_lock *lock,
 847        const unsigned char *old_sha1, int mustexist)
 848{
 849        if (!resolve_ref(lock->ref_name, lock->old_sha1, mustexist, NULL)) {
 850                error("Can't verify ref %s", lock->ref_name);
 851                unlock_ref(lock);
 852                return NULL;
 853        }
 854        if (hashcmp(lock->old_sha1, old_sha1)) {
 855                error("Ref %s is at %s but expected %s", lock->ref_name,
 856                        sha1_to_hex(lock->old_sha1), sha1_to_hex(old_sha1));
 857                unlock_ref(lock);
 858                return NULL;
 859        }
 860        return lock;
 861}
 862
 863static int remove_empty_directories(const char *file)
 864{
 865        /* we want to create a file but there is a directory there;
 866         * if that is an empty directory (or a directory that contains
 867         * only empty directories), remove them.
 868         */
 869        struct strbuf path;
 870        int result;
 871
 872        strbuf_init(&path, 20);
 873        strbuf_addstr(&path, file);
 874
 875        result = remove_dir_recursively(&path, REMOVE_DIR_EMPTY_ONLY);
 876
 877        strbuf_release(&path);
 878
 879        return result;
 880}
 881
 882static int is_refname_available(const char *ref, const char *oldref,
 883                                struct ref_list *list, int quiet)
 884{
 885        int namlen = strlen(ref); /* e.g. 'foo/bar' */
 886        while (list) {
 887                /* list->name could be 'foo' or 'foo/bar/baz' */
 888                if (!oldref || strcmp(oldref, list->name)) {
 889                        int len = strlen(list->name);
 890                        int cmplen = (namlen < len) ? namlen : len;
 891                        const char *lead = (namlen < len) ? list->name : ref;
 892                        if (!strncmp(ref, list->name, cmplen) &&
 893                            lead[cmplen] == '/') {
 894                                if (!quiet)
 895                                        error("'%s' exists; cannot create '%s'",
 896                                              list->name, ref);
 897                                return 0;
 898                        }
 899                }
 900                list = list->next;
 901        }
 902        return 1;
 903}
 904
 905static struct ref_lock *lock_ref_sha1_basic(const char *ref, const unsigned char *old_sha1, int flags, int *type_p)
 906{
 907        char *ref_file;
 908        const char *orig_ref = ref;
 909        struct ref_lock *lock;
 910        int last_errno = 0;
 911        int type, lflags;
 912        int mustexist = (old_sha1 && !is_null_sha1(old_sha1));
 913        int missing = 0;
 914
 915        lock = xcalloc(1, sizeof(struct ref_lock));
 916        lock->lock_fd = -1;
 917
 918        ref = resolve_ref(ref, lock->old_sha1, mustexist, &type);
 919        if (!ref && errno == EISDIR) {
 920                /* we are trying to lock foo but we used to
 921                 * have foo/bar which now does not exist;
 922                 * it is normal for the empty directory 'foo'
 923                 * to remain.
 924                 */
 925                ref_file = git_path("%s", orig_ref);
 926                if (remove_empty_directories(ref_file)) {
 927                        last_errno = errno;
 928                        error("there are still refs under '%s'", orig_ref);
 929                        goto error_return;
 930                }
 931                ref = resolve_ref(orig_ref, lock->old_sha1, mustexist, &type);
 932        }
 933        if (type_p)
 934            *type_p = type;
 935        if (!ref) {
 936                last_errno = errno;
 937                error("unable to resolve reference %s: %s",
 938                        orig_ref, strerror(errno));
 939                goto error_return;
 940        }
 941        missing = is_null_sha1(lock->old_sha1);
 942        /* When the ref did not exist and we are creating it,
 943         * make sure there is no existing ref that is packed
 944         * whose name begins with our refname, nor a ref whose
 945         * name is a proper prefix of our refname.
 946         */
 947        if (missing &&
 948             !is_refname_available(ref, NULL, get_packed_refs(), 0)) {
 949                last_errno = ENOTDIR;
 950                goto error_return;
 951        }
 952
 953        lock->lk = xcalloc(1, sizeof(struct lock_file));
 954
 955        lflags = LOCK_DIE_ON_ERROR;
 956        if (flags & REF_NODEREF) {
 957                ref = orig_ref;
 958                lflags |= LOCK_NODEREF;
 959        }
 960        lock->ref_name = xstrdup(ref);
 961        lock->orig_ref_name = xstrdup(orig_ref);
 962        ref_file = git_path("%s", ref);
 963        if (missing)
 964                lock->force_write = 1;
 965        if ((flags & REF_NODEREF) && (type & REF_ISSYMREF))
 966                lock->force_write = 1;
 967
 968        if (safe_create_leading_directories(ref_file)) {
 969                last_errno = errno;
 970                error("unable to create directory for %s", ref_file);
 971                goto error_return;
 972        }
 973
 974        lock->lock_fd = hold_lock_file_for_update(lock->lk, ref_file, lflags);
 975        return old_sha1 ? verify_lock(lock, old_sha1, mustexist) : lock;
 976
 977 error_return:
 978        unlock_ref(lock);
 979        errno = last_errno;
 980        return NULL;
 981}
 982
 983struct ref_lock *lock_ref_sha1(const char *ref, const unsigned char *old_sha1)
 984{
 985        char refpath[PATH_MAX];
 986        if (check_ref_format(ref))
 987                return NULL;
 988        strcpy(refpath, mkpath("refs/%s", ref));
 989        return lock_ref_sha1_basic(refpath, old_sha1, 0, NULL);
 990}
 991
 992struct ref_lock *lock_any_ref_for_update(const char *ref, const unsigned char *old_sha1, int flags)
 993{
 994        switch (check_ref_format(ref)) {
 995        default:
 996                return NULL;
 997        case 0:
 998        case CHECK_REF_FORMAT_ONELEVEL:
 999                return lock_ref_sha1_basic(ref, old_sha1, flags, NULL);
1000        }
1001}
1002
1003static struct lock_file packlock;
1004
1005static int repack_without_ref(const char *refname)
1006{
1007        struct ref_list *list, *packed_ref_list;
1008        int fd;
1009        int found = 0;
1010
1011        packed_ref_list = get_packed_refs();
1012        for (list = packed_ref_list; list; list = list->next) {
1013                if (!strcmp(refname, list->name)) {
1014                        found = 1;
1015                        break;
1016                }
1017        }
1018        if (!found)
1019                return 0;
1020        fd = hold_lock_file_for_update(&packlock, git_path("packed-refs"), 0);
1021        if (fd < 0) {
1022                unable_to_lock_error(git_path("packed-refs"), errno);
1023                return error("cannot delete '%s' from packed refs", refname);
1024        }
1025
1026        for (list = packed_ref_list; list; list = list->next) {
1027                char line[PATH_MAX + 100];
1028                int len;
1029
1030                if (!strcmp(refname, list->name))
1031                        continue;
1032                len = snprintf(line, sizeof(line), "%s %s\n",
1033                               sha1_to_hex(list->sha1), list->name);
1034                /* this should not happen but just being defensive */
1035                if (len > sizeof(line))
1036                        die("too long a refname '%s'", list->name);
1037                write_or_die(fd, line, len);
1038        }
1039        return commit_lock_file(&packlock);
1040}
1041
1042int delete_ref(const char *refname, const unsigned char *sha1, int delopt)
1043{
1044        struct ref_lock *lock;
1045        int err, i = 0, ret = 0, flag = 0;
1046
1047        lock = lock_ref_sha1_basic(refname, sha1, 0, &flag);
1048        if (!lock)
1049                return 1;
1050        if (!(flag & REF_ISPACKED) || flag & REF_ISSYMREF) {
1051                /* loose */
1052                const char *path;
1053
1054                if (!(delopt & REF_NODEREF)) {
1055                        i = strlen(lock->lk->filename) - 5; /* .lock */
1056                        lock->lk->filename[i] = 0;
1057                        path = lock->lk->filename;
1058                } else {
1059                        path = git_path("%s", refname);
1060                }
1061                err = unlink_or_warn(path);
1062                if (err && errno != ENOENT)
1063                        ret = 1;
1064
1065                if (!(delopt & REF_NODEREF))
1066                        lock->lk->filename[i] = '.';
1067        }
1068        /* removing the loose one could have resurrected an earlier
1069         * packed one.  Also, if it was not loose we need to repack
1070         * without it.
1071         */
1072        ret |= repack_without_ref(refname);
1073
1074        unlink_or_warn(git_path("logs/%s", lock->ref_name));
1075        invalidate_cached_refs();
1076        unlock_ref(lock);
1077        return ret;
1078}
1079
1080int rename_ref(const char *oldref, const char *newref, const char *logmsg)
1081{
1082        static const char renamed_ref[] = "RENAMED-REF";
1083        unsigned char sha1[20], orig_sha1[20];
1084        int flag = 0, logmoved = 0;
1085        struct ref_lock *lock;
1086        struct stat loginfo;
1087        int log = !lstat(git_path("logs/%s", oldref), &loginfo);
1088        const char *symref = NULL;
1089
1090        if (log && S_ISLNK(loginfo.st_mode))
1091                return error("reflog for %s is a symlink", oldref);
1092
1093        symref = resolve_ref(oldref, orig_sha1, 1, &flag);
1094        if (flag & REF_ISSYMREF)
1095                return error("refname %s is a symbolic ref, renaming it is not supported",
1096                        oldref);
1097        if (!symref)
1098                return error("refname %s not found", oldref);
1099
1100        if (!is_refname_available(newref, oldref, get_packed_refs(), 0))
1101                return 1;
1102
1103        if (!is_refname_available(newref, oldref, get_loose_refs(), 0))
1104                return 1;
1105
1106        lock = lock_ref_sha1_basic(renamed_ref, NULL, 0, NULL);
1107        if (!lock)
1108                return error("unable to lock %s", renamed_ref);
1109        lock->force_write = 1;
1110        if (write_ref_sha1(lock, orig_sha1, logmsg))
1111                return error("unable to save current sha1 in %s", renamed_ref);
1112
1113        if (log && rename(git_path("logs/%s", oldref), git_path("tmp-renamed-log")))
1114                return error("unable to move logfile logs/%s to tmp-renamed-log: %s",
1115                        oldref, strerror(errno));
1116
1117        if (delete_ref(oldref, orig_sha1, REF_NODEREF)) {
1118                error("unable to delete old %s", oldref);
1119                goto rollback;
1120        }
1121
1122        if (resolve_ref(newref, sha1, 1, &flag) && delete_ref(newref, sha1, REF_NODEREF)) {
1123                if (errno==EISDIR) {
1124                        if (remove_empty_directories(git_path("%s", newref))) {
1125                                error("Directory not empty: %s", newref);
1126                                goto rollback;
1127                        }
1128                } else {
1129                        error("unable to delete existing %s", newref);
1130                        goto rollback;
1131                }
1132        }
1133
1134        if (log && safe_create_leading_directories(git_path("logs/%s", newref))) {
1135                error("unable to create directory for %s", newref);
1136                goto rollback;
1137        }
1138
1139 retry:
1140        if (log && rename(git_path("tmp-renamed-log"), git_path("logs/%s", newref))) {
1141                if (errno==EISDIR || errno==ENOTDIR) {
1142                        /*
1143                         * rename(a, b) when b is an existing
1144                         * directory ought to result in ISDIR, but
1145                         * Solaris 5.8 gives ENOTDIR.  Sheesh.
1146                         */
1147                        if (remove_empty_directories(git_path("logs/%s", newref))) {
1148                                error("Directory not empty: logs/%s", newref);
1149                                goto rollback;
1150                        }
1151                        goto retry;
1152                } else {
1153                        error("unable to move logfile tmp-renamed-log to logs/%s: %s",
1154                                newref, strerror(errno));
1155                        goto rollback;
1156                }
1157        }
1158        logmoved = log;
1159
1160        lock = lock_ref_sha1_basic(newref, NULL, 0, NULL);
1161        if (!lock) {
1162                error("unable to lock %s for update", newref);
1163                goto rollback;
1164        }
1165        lock->force_write = 1;
1166        hashcpy(lock->old_sha1, orig_sha1);
1167        if (write_ref_sha1(lock, orig_sha1, logmsg)) {
1168                error("unable to write current sha1 into %s", newref);
1169                goto rollback;
1170        }
1171
1172        return 0;
1173
1174 rollback:
1175        lock = lock_ref_sha1_basic(oldref, NULL, 0, NULL);
1176        if (!lock) {
1177                error("unable to lock %s for rollback", oldref);
1178                goto rollbacklog;
1179        }
1180
1181        lock->force_write = 1;
1182        flag = log_all_ref_updates;
1183        log_all_ref_updates = 0;
1184        if (write_ref_sha1(lock, orig_sha1, NULL))
1185                error("unable to write current sha1 into %s", oldref);
1186        log_all_ref_updates = flag;
1187
1188 rollbacklog:
1189        if (logmoved && rename(git_path("logs/%s", newref), git_path("logs/%s", oldref)))
1190                error("unable to restore logfile %s from %s: %s",
1191                        oldref, newref, strerror(errno));
1192        if (!logmoved && log &&
1193            rename(git_path("tmp-renamed-log"), git_path("logs/%s", oldref)))
1194                error("unable to restore logfile %s from tmp-renamed-log: %s",
1195                        oldref, strerror(errno));
1196
1197        return 1;
1198}
1199
1200int close_ref(struct ref_lock *lock)
1201{
1202        if (close_lock_file(lock->lk))
1203                return -1;
1204        lock->lock_fd = -1;
1205        return 0;
1206}
1207
1208int commit_ref(struct ref_lock *lock)
1209{
1210        if (commit_lock_file(lock->lk))
1211                return -1;
1212        lock->lock_fd = -1;
1213        return 0;
1214}
1215
1216void unlock_ref(struct ref_lock *lock)
1217{
1218        /* Do not free lock->lk -- atexit() still looks at them */
1219        if (lock->lk)
1220                rollback_lock_file(lock->lk);
1221        free(lock->ref_name);
1222        free(lock->orig_ref_name);
1223        free(lock);
1224}
1225
1226/*
1227 * copy the reflog message msg to buf, which has been allocated sufficiently
1228 * large, while cleaning up the whitespaces.  Especially, convert LF to space,
1229 * because reflog file is one line per entry.
1230 */
1231static int copy_msg(char *buf, const char *msg)
1232{
1233        char *cp = buf;
1234        char c;
1235        int wasspace = 1;
1236
1237        *cp++ = '\t';
1238        while ((c = *msg++)) {
1239                if (wasspace && isspace(c))
1240                        continue;
1241                wasspace = isspace(c);
1242                if (wasspace)
1243                        c = ' ';
1244                *cp++ = c;
1245        }
1246        while (buf < cp && isspace(cp[-1]))
1247                cp--;
1248        *cp++ = '\n';
1249        return cp - buf;
1250}
1251
1252static int log_ref_write(const char *ref_name, const unsigned char *old_sha1,
1253                         const unsigned char *new_sha1, const char *msg)
1254{
1255        int logfd, written, oflags = O_APPEND | O_WRONLY;
1256        unsigned maxlen, len;
1257        int msglen;
1258        char log_file[PATH_MAX];
1259        char *logrec;
1260        const char *committer;
1261
1262        if (log_all_ref_updates < 0)
1263                log_all_ref_updates = !is_bare_repository();
1264
1265        git_snpath(log_file, sizeof(log_file), "logs/%s", ref_name);
1266
1267        if (log_all_ref_updates &&
1268            (!prefixcmp(ref_name, "refs/heads/") ||
1269             !prefixcmp(ref_name, "refs/remotes/") ||
1270             !strcmp(ref_name, "HEAD"))) {
1271                if (safe_create_leading_directories(log_file) < 0)
1272                        return error("unable to create directory for %s",
1273                                     log_file);
1274                oflags |= O_CREAT;
1275        }
1276
1277        logfd = open(log_file, oflags, 0666);
1278        if (logfd < 0) {
1279                if (!(oflags & O_CREAT) && errno == ENOENT)
1280                        return 0;
1281
1282                if ((oflags & O_CREAT) && errno == EISDIR) {
1283                        if (remove_empty_directories(log_file)) {
1284                                return error("There are still logs under '%s'",
1285                                             log_file);
1286                        }
1287                        logfd = open(log_file, oflags, 0666);
1288                }
1289
1290                if (logfd < 0)
1291                        return error("Unable to append to %s: %s",
1292                                     log_file, strerror(errno));
1293        }
1294
1295        adjust_shared_perm(log_file);
1296
1297        msglen = msg ? strlen(msg) : 0;
1298        committer = git_committer_info(0);
1299        maxlen = strlen(committer) + msglen + 100;
1300        logrec = xmalloc(maxlen);
1301        len = sprintf(logrec, "%s %s %s\n",
1302                      sha1_to_hex(old_sha1),
1303                      sha1_to_hex(new_sha1),
1304                      committer);
1305        if (msglen)
1306                len += copy_msg(logrec + len - 1, msg) - 1;
1307        written = len <= maxlen ? write_in_full(logfd, logrec, len) : -1;
1308        free(logrec);
1309        if (close(logfd) != 0 || written != len)
1310                return error("Unable to append to %s", log_file);
1311        return 0;
1312}
1313
1314static int is_branch(const char *refname)
1315{
1316        return !strcmp(refname, "HEAD") || !prefixcmp(refname, "refs/heads/");
1317}
1318
1319int write_ref_sha1(struct ref_lock *lock,
1320        const unsigned char *sha1, const char *logmsg)
1321{
1322        static char term = '\n';
1323        struct object *o;
1324
1325        if (!lock)
1326                return -1;
1327        if (!lock->force_write && !hashcmp(lock->old_sha1, sha1)) {
1328                unlock_ref(lock);
1329                return 0;
1330        }
1331        o = parse_object(sha1);
1332        if (!o) {
1333                error("Trying to write ref %s with nonexistant object %s",
1334                        lock->ref_name, sha1_to_hex(sha1));
1335                unlock_ref(lock);
1336                return -1;
1337        }
1338        if (o->type != OBJ_COMMIT && is_branch(lock->ref_name)) {
1339                error("Trying to write non-commit object %s to branch %s",
1340                        sha1_to_hex(sha1), lock->ref_name);
1341                unlock_ref(lock);
1342                return -1;
1343        }
1344        if (write_in_full(lock->lock_fd, sha1_to_hex(sha1), 40) != 40 ||
1345            write_in_full(lock->lock_fd, &term, 1) != 1
1346                || close_ref(lock) < 0) {
1347                error("Couldn't write %s", lock->lk->filename);
1348                unlock_ref(lock);
1349                return -1;
1350        }
1351        invalidate_cached_refs();
1352        if (log_ref_write(lock->ref_name, lock->old_sha1, sha1, logmsg) < 0 ||
1353            (strcmp(lock->ref_name, lock->orig_ref_name) &&
1354             log_ref_write(lock->orig_ref_name, lock->old_sha1, sha1, logmsg) < 0)) {
1355                unlock_ref(lock);
1356                return -1;
1357        }
1358        if (strcmp(lock->orig_ref_name, "HEAD") != 0) {
1359                /*
1360                 * Special hack: If a branch is updated directly and HEAD
1361                 * points to it (may happen on the remote side of a push
1362                 * for example) then logically the HEAD reflog should be
1363                 * updated too.
1364                 * A generic solution implies reverse symref information,
1365                 * but finding all symrefs pointing to the given branch
1366                 * would be rather costly for this rare event (the direct
1367                 * update of a branch) to be worth it.  So let's cheat and
1368                 * check with HEAD only which should cover 99% of all usage
1369                 * scenarios (even 100% of the default ones).
1370                 */
1371                unsigned char head_sha1[20];
1372                int head_flag;
1373                const char *head_ref;
1374                head_ref = resolve_ref("HEAD", head_sha1, 1, &head_flag);
1375                if (head_ref && (head_flag & REF_ISSYMREF) &&
1376                    !strcmp(head_ref, lock->ref_name))
1377                        log_ref_write("HEAD", lock->old_sha1, sha1, logmsg);
1378        }
1379        if (commit_ref(lock)) {
1380                error("Couldn't set %s", lock->ref_name);
1381                unlock_ref(lock);
1382                return -1;
1383        }
1384        unlock_ref(lock);
1385        return 0;
1386}
1387
1388int create_symref(const char *ref_target, const char *refs_heads_master,
1389                  const char *logmsg)
1390{
1391        const char *lockpath;
1392        char ref[1000];
1393        int fd, len, written;
1394        char *git_HEAD = git_pathdup("%s", ref_target);
1395        unsigned char old_sha1[20], new_sha1[20];
1396
1397        if (logmsg && read_ref(ref_target, old_sha1))
1398                hashclr(old_sha1);
1399
1400        if (safe_create_leading_directories(git_HEAD) < 0)
1401                return error("unable to create directory for %s", git_HEAD);
1402
1403#ifndef NO_SYMLINK_HEAD
1404        if (prefer_symlink_refs) {
1405                unlink(git_HEAD);
1406                if (!symlink(refs_heads_master, git_HEAD))
1407                        goto done;
1408                fprintf(stderr, "no symlink - falling back to symbolic ref\n");
1409        }
1410#endif
1411
1412        len = snprintf(ref, sizeof(ref), "ref: %s\n", refs_heads_master);
1413        if (sizeof(ref) <= len) {
1414                error("refname too long: %s", refs_heads_master);
1415                goto error_free_return;
1416        }
1417        lockpath = mkpath("%s.lock", git_HEAD);
1418        fd = open(lockpath, O_CREAT | O_EXCL | O_WRONLY, 0666);
1419        if (fd < 0) {
1420                error("Unable to open %s for writing", lockpath);
1421                goto error_free_return;
1422        }
1423        written = write_in_full(fd, ref, len);
1424        if (close(fd) != 0 || written != len) {
1425                error("Unable to write to %s", lockpath);
1426                goto error_unlink_return;
1427        }
1428        if (rename(lockpath, git_HEAD) < 0) {
1429                error("Unable to create %s", git_HEAD);
1430                goto error_unlink_return;
1431        }
1432        if (adjust_shared_perm(git_HEAD)) {
1433                error("Unable to fix permissions on %s", lockpath);
1434        error_unlink_return:
1435                unlink_or_warn(lockpath);
1436        error_free_return:
1437                free(git_HEAD);
1438                return -1;
1439        }
1440
1441#ifndef NO_SYMLINK_HEAD
1442        done:
1443#endif
1444        if (logmsg && !read_ref(refs_heads_master, new_sha1))
1445                log_ref_write(ref_target, old_sha1, new_sha1, logmsg);
1446
1447        free(git_HEAD);
1448        return 0;
1449}
1450
1451static char *ref_msg(const char *line, const char *endp)
1452{
1453        const char *ep;
1454        line += 82;
1455        ep = memchr(line, '\n', endp - line);
1456        if (!ep)
1457                ep = endp;
1458        return xmemdupz(line, ep - line);
1459}
1460
1461int 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)
1462{
1463        const char *logfile, *logdata, *logend, *rec, *lastgt, *lastrec;
1464        char *tz_c;
1465        int logfd, tz, reccnt = 0;
1466        struct stat st;
1467        unsigned long date;
1468        unsigned char logged_sha1[20];
1469        void *log_mapped;
1470        size_t mapsz;
1471
1472        logfile = git_path("logs/%s", ref);
1473        logfd = open(logfile, O_RDONLY, 0);
1474        if (logfd < 0)
1475                die_errno("Unable to read log '%s'", logfile);
1476        fstat(logfd, &st);
1477        if (!st.st_size)
1478                die("Log %s is empty.", logfile);
1479        mapsz = xsize_t(st.st_size);
1480        log_mapped = xmmap(NULL, mapsz, PROT_READ, MAP_PRIVATE, logfd, 0);
1481        logdata = log_mapped;
1482        close(logfd);
1483
1484        lastrec = NULL;
1485        rec = logend = logdata + st.st_size;
1486        while (logdata < rec) {
1487                reccnt++;
1488                if (logdata < rec && *(rec-1) == '\n')
1489                        rec--;
1490                lastgt = NULL;
1491                while (logdata < rec && *(rec-1) != '\n') {
1492                        rec--;
1493                        if (*rec == '>')
1494                                lastgt = rec;
1495                }
1496                if (!lastgt)
1497                        die("Log %s is corrupt.", logfile);
1498                date = strtoul(lastgt + 1, &tz_c, 10);
1499                if (date <= at_time || cnt == 0) {
1500                        tz = strtoul(tz_c, NULL, 10);
1501                        if (msg)
1502                                *msg = ref_msg(rec, logend);
1503                        if (cutoff_time)
1504                                *cutoff_time = date;
1505                        if (cutoff_tz)
1506                                *cutoff_tz = tz;
1507                        if (cutoff_cnt)
1508                                *cutoff_cnt = reccnt - 1;
1509                        if (lastrec) {
1510                                if (get_sha1_hex(lastrec, logged_sha1))
1511                                        die("Log %s is corrupt.", logfile);
1512                                if (get_sha1_hex(rec + 41, sha1))
1513                                        die("Log %s is corrupt.", logfile);
1514                                if (hashcmp(logged_sha1, sha1)) {
1515                                        warning("Log %s has gap after %s.",
1516                                                logfile, show_date(date, tz, DATE_RFC2822));
1517                                }
1518                        }
1519                        else if (date == at_time) {
1520                                if (get_sha1_hex(rec + 41, sha1))
1521                                        die("Log %s is corrupt.", logfile);
1522                        }
1523                        else {
1524                                if (get_sha1_hex(rec + 41, logged_sha1))
1525                                        die("Log %s is corrupt.", logfile);
1526                                if (hashcmp(logged_sha1, sha1)) {
1527                                        warning("Log %s unexpectedly ended on %s.",
1528                                                logfile, show_date(date, tz, DATE_RFC2822));
1529                                }
1530                        }
1531                        munmap(log_mapped, mapsz);
1532                        return 0;
1533                }
1534                lastrec = rec;
1535                if (cnt > 0)
1536                        cnt--;
1537        }
1538
1539        rec = logdata;
1540        while (rec < logend && *rec != '>' && *rec != '\n')
1541                rec++;
1542        if (rec == logend || *rec == '\n')
1543                die("Log %s is corrupt.", logfile);
1544        date = strtoul(rec + 1, &tz_c, 10);
1545        tz = strtoul(tz_c, NULL, 10);
1546        if (get_sha1_hex(logdata, sha1))
1547                die("Log %s is corrupt.", logfile);
1548        if (is_null_sha1(sha1)) {
1549                if (get_sha1_hex(logdata + 41, sha1))
1550                        die("Log %s is corrupt.", logfile);
1551        }
1552        if (msg)
1553                *msg = ref_msg(logdata, logend);
1554        munmap(log_mapped, mapsz);
1555
1556        if (cutoff_time)
1557                *cutoff_time = date;
1558        if (cutoff_tz)
1559                *cutoff_tz = tz;
1560        if (cutoff_cnt)
1561                *cutoff_cnt = reccnt;
1562        return 1;
1563}
1564
1565int for_each_recent_reflog_ent(const char *ref, each_reflog_ent_fn fn, long ofs, void *cb_data)
1566{
1567        const char *logfile;
1568        FILE *logfp;
1569        char buf[1024];
1570        int ret = 0;
1571
1572        logfile = git_path("logs/%s", ref);
1573        logfp = fopen(logfile, "r");
1574        if (!logfp)
1575                return -1;
1576
1577        if (ofs) {
1578                struct stat statbuf;
1579                if (fstat(fileno(logfp), &statbuf) ||
1580                    statbuf.st_size < ofs ||
1581                    fseek(logfp, -ofs, SEEK_END) ||
1582                    fgets(buf, sizeof(buf), logfp)) {
1583                        fclose(logfp);
1584                        return -1;
1585                }
1586        }
1587
1588        while (fgets(buf, sizeof(buf), logfp)) {
1589                unsigned char osha1[20], nsha1[20];
1590                char *email_end, *message;
1591                unsigned long timestamp;
1592                int len, tz;
1593
1594                /* old SP new SP name <email> SP time TAB msg LF */
1595                len = strlen(buf);
1596                if (len < 83 || buf[len-1] != '\n' ||
1597                    get_sha1_hex(buf, osha1) || buf[40] != ' ' ||
1598                    get_sha1_hex(buf + 41, nsha1) || buf[81] != ' ' ||
1599                    !(email_end = strchr(buf + 82, '>')) ||
1600                    email_end[1] != ' ' ||
1601                    !(timestamp = strtoul(email_end + 2, &message, 10)) ||
1602                    !message || message[0] != ' ' ||
1603                    (message[1] != '+' && message[1] != '-') ||
1604                    !isdigit(message[2]) || !isdigit(message[3]) ||
1605                    !isdigit(message[4]) || !isdigit(message[5]))
1606                        continue; /* corrupt? */
1607                email_end[1] = '\0';
1608                tz = strtol(message + 1, NULL, 10);
1609                if (message[6] != '\t')
1610                        message += 6;
1611                else
1612                        message += 7;
1613                ret = fn(osha1, nsha1, buf+82, timestamp, tz, message, cb_data);
1614                if (ret)
1615                        break;
1616        }
1617        fclose(logfp);
1618        return ret;
1619}
1620
1621int for_each_reflog_ent(const char *ref, each_reflog_ent_fn fn, void *cb_data)
1622{
1623        return for_each_recent_reflog_ent(ref, fn, 0, cb_data);
1624}
1625
1626static int do_for_each_reflog(const char *base, each_ref_fn fn, void *cb_data)
1627{
1628        DIR *dir = opendir(git_path("logs/%s", base));
1629        int retval = 0;
1630
1631        if (dir) {
1632                struct dirent *de;
1633                int baselen = strlen(base);
1634                char *log = xmalloc(baselen + 257);
1635
1636                memcpy(log, base, baselen);
1637                if (baselen && base[baselen-1] != '/')
1638                        log[baselen++] = '/';
1639
1640                while ((de = readdir(dir)) != NULL) {
1641                        struct stat st;
1642                        int namelen;
1643
1644                        if (de->d_name[0] == '.')
1645                                continue;
1646                        namelen = strlen(de->d_name);
1647                        if (namelen > 255)
1648                                continue;
1649                        if (has_extension(de->d_name, ".lock"))
1650                                continue;
1651                        memcpy(log + baselen, de->d_name, namelen+1);
1652                        if (stat(git_path("logs/%s", log), &st) < 0)
1653                                continue;
1654                        if (S_ISDIR(st.st_mode)) {
1655                                retval = do_for_each_reflog(log, fn, cb_data);
1656                        } else {
1657                                unsigned char sha1[20];
1658                                if (!resolve_ref(log, sha1, 0, NULL))
1659                                        retval = error("bad ref for %s", log);
1660                                else
1661                                        retval = fn(log, sha1, 0, cb_data);
1662                        }
1663                        if (retval)
1664                                break;
1665                }
1666                free(log);
1667                closedir(dir);
1668        }
1669        else if (*base)
1670                return errno;
1671        return retval;
1672}
1673
1674int for_each_reflog(each_ref_fn fn, void *cb_data)
1675{
1676        return do_for_each_reflog("", fn, cb_data);
1677}
1678
1679int update_ref(const char *action, const char *refname,
1680                const unsigned char *sha1, const unsigned char *oldval,
1681                int flags, enum action_on_err onerr)
1682{
1683        static struct ref_lock *lock;
1684        lock = lock_any_ref_for_update(refname, oldval, flags);
1685        if (!lock) {
1686                const char *str = "Cannot lock the ref '%s'.";
1687                switch (onerr) {
1688                case MSG_ON_ERR: error(str, refname); break;
1689                case DIE_ON_ERR: die(str, refname); break;
1690                case QUIET_ON_ERR: break;
1691                }
1692                return 1;
1693        }
1694        if (write_ref_sha1(lock, sha1, action) < 0) {
1695                const char *str = "Cannot update the ref '%s'.";
1696                switch (onerr) {
1697                case MSG_ON_ERR: error(str, refname); break;
1698                case DIE_ON_ERR: die(str, refname); break;
1699                case QUIET_ON_ERR: break;
1700                }
1701                return 1;
1702        }
1703        return 0;
1704}
1705
1706struct ref *find_ref_by_name(const struct ref *list, const char *name)
1707{
1708        for ( ; list; list = list->next)
1709                if (!strcmp(list->name, name))
1710                        return (struct ref *)list;
1711        return NULL;
1712}
1713
1714/*
1715 * generate a format suitable for scanf from a ref_rev_parse_rules
1716 * rule, that is replace the "%.*s" spec with a "%s" spec
1717 */
1718static void gen_scanf_fmt(char *scanf_fmt, const char *rule)
1719{
1720        char *spec;
1721
1722        spec = strstr(rule, "%.*s");
1723        if (!spec || strstr(spec + 4, "%.*s"))
1724                die("invalid rule in ref_rev_parse_rules: %s", rule);
1725
1726        /* copy all until spec */
1727        strncpy(scanf_fmt, rule, spec - rule);
1728        scanf_fmt[spec - rule] = '\0';
1729        /* copy new spec */
1730        strcat(scanf_fmt, "%s");
1731        /* copy remaining rule */
1732        strcat(scanf_fmt, spec + 4);
1733
1734        return;
1735}
1736
1737char *shorten_unambiguous_ref(const char *ref, int strict)
1738{
1739        int i;
1740        static char **scanf_fmts;
1741        static int nr_rules;
1742        char *short_name;
1743
1744        /* pre generate scanf formats from ref_rev_parse_rules[] */
1745        if (!nr_rules) {
1746                size_t total_len = 0;
1747
1748                /* the rule list is NULL terminated, count them first */
1749                for (; ref_rev_parse_rules[nr_rules]; nr_rules++)
1750                        /* no +1 because strlen("%s") < strlen("%.*s") */
1751                        total_len += strlen(ref_rev_parse_rules[nr_rules]);
1752
1753                scanf_fmts = xmalloc(nr_rules * sizeof(char *) + total_len);
1754
1755                total_len = 0;
1756                for (i = 0; i < nr_rules; i++) {
1757                        scanf_fmts[i] = (char *)&scanf_fmts[nr_rules]
1758                                        + total_len;
1759                        gen_scanf_fmt(scanf_fmts[i], ref_rev_parse_rules[i]);
1760                        total_len += strlen(ref_rev_parse_rules[i]);
1761                }
1762        }
1763
1764        /* bail out if there are no rules */
1765        if (!nr_rules)
1766                return xstrdup(ref);
1767
1768        /* buffer for scanf result, at most ref must fit */
1769        short_name = xstrdup(ref);
1770
1771        /* skip first rule, it will always match */
1772        for (i = nr_rules - 1; i > 0 ; --i) {
1773                int j;
1774                int rules_to_fail = i;
1775                int short_name_len;
1776
1777                if (1 != sscanf(ref, scanf_fmts[i], short_name))
1778                        continue;
1779
1780                short_name_len = strlen(short_name);
1781
1782                /*
1783                 * in strict mode, all (except the matched one) rules
1784                 * must fail to resolve to a valid non-ambiguous ref
1785                 */
1786                if (strict)
1787                        rules_to_fail = nr_rules;
1788
1789                /*
1790                 * check if the short name resolves to a valid ref,
1791                 * but use only rules prior to the matched one
1792                 */
1793                for (j = 0; j < rules_to_fail; j++) {
1794                        const char *rule = ref_rev_parse_rules[j];
1795                        unsigned char short_objectname[20];
1796                        char refname[PATH_MAX];
1797
1798                        /* skip matched rule */
1799                        if (i == j)
1800                                continue;
1801
1802                        /*
1803                         * the short name is ambiguous, if it resolves
1804                         * (with this previous rule) to a valid ref
1805                         * read_ref() returns 0 on success
1806                         */
1807                        mksnpath(refname, sizeof(refname),
1808                                 rule, short_name_len, short_name);
1809                        if (!read_ref(refname, short_objectname))
1810                                break;
1811                }
1812
1813                /*
1814                 * short name is non-ambiguous if all previous rules
1815                 * haven't resolved to a valid ref
1816                 */
1817                if (j == rules_to_fail)
1818                        return short_name;
1819        }
1820
1821        free(short_name);
1822        return xstrdup(ref);
1823}