refs.con commit Merge branch 'bg/send-email-smtpdomain' into maint (419ff2c)
   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#define REF_BROKEN 010
  10
  11struct ref_list {
  12        struct ref_list *next;
  13        unsigned char flag; /* ISSYMREF? ISPACKED? */
  14        unsigned char sha1[20];
  15        unsigned char peeled[20];
  16        char name[FLEX_ARRAY];
  17};
  18
  19static const char *parse_ref_line(char *line, unsigned char *sha1)
  20{
  21        /*
  22         * 42: the answer to everything.
  23         *
  24         * In this case, it happens to be the answer to
  25         *  40 (length of sha1 hex representation)
  26         *  +1 (space in between hex and name)
  27         *  +1 (newline at the end of the line)
  28         */
  29        int len = strlen(line) - 42;
  30
  31        if (len <= 0)
  32                return NULL;
  33        if (get_sha1_hex(line, sha1) < 0)
  34                return NULL;
  35        if (!isspace(line[40]))
  36                return NULL;
  37        line += 41;
  38        if (isspace(*line))
  39                return NULL;
  40        if (line[len] != '\n')
  41                return NULL;
  42        line[len] = 0;
  43
  44        return line;
  45}
  46
  47static struct ref_list *add_ref(const char *name, const unsigned char *sha1,
  48                                int flag, struct ref_list *list,
  49                                struct ref_list **new_entry)
  50{
  51        int len;
  52        struct ref_list *entry;
  53
  54        /* Allocate it and add it in.. */
  55        len = strlen(name) + 1;
  56        entry = xmalloc(sizeof(struct ref_list) + len);
  57        hashcpy(entry->sha1, sha1);
  58        hashclr(entry->peeled);
  59        memcpy(entry->name, name, len);
  60        entry->flag = flag;
  61        entry->next = list;
  62        if (new_entry)
  63                *new_entry = entry;
  64        return entry;
  65}
  66
  67/* merge sort the ref list */
  68static struct ref_list *sort_ref_list(struct ref_list *list)
  69{
  70        int psize, qsize, last_merge_count, cmp;
  71        struct ref_list *p, *q, *l, *e;
  72        struct ref_list *new_list = list;
  73        int k = 1;
  74        int merge_count = 0;
  75
  76        if (!list)
  77                return list;
  78
  79        do {
  80                last_merge_count = merge_count;
  81                merge_count = 0;
  82
  83                psize = 0;
  84
  85                p = new_list;
  86                q = new_list;
  87                new_list = NULL;
  88                l = NULL;
  89
  90                while (p) {
  91                        merge_count++;
  92
  93                        while (psize < k && q->next) {
  94                                q = q->next;
  95                                psize++;
  96                        }
  97                        qsize = k;
  98
  99                        while ((psize > 0) || (qsize > 0 && q)) {
 100                                if (qsize == 0 || !q) {
 101                                        e = p;
 102                                        p = p->next;
 103                                        psize--;
 104                                } else if (psize == 0) {
 105                                        e = q;
 106                                        q = q->next;
 107                                        qsize--;
 108                                } else {
 109                                        cmp = strcmp(q->name, p->name);
 110                                        if (cmp < 0) {
 111                                                e = q;
 112                                                q = q->next;
 113                                                qsize--;
 114                                        } else if (cmp > 0) {
 115                                                e = p;
 116                                                p = p->next;
 117                                                psize--;
 118                                        } else {
 119                                                if (hashcmp(q->sha1, p->sha1))
 120                                                        die("Duplicated ref, and SHA1s don't match: %s",
 121                                                            q->name);
 122                                                warning("Duplicated ref: %s", q->name);
 123                                                e = q;
 124                                                q = q->next;
 125                                                qsize--;
 126                                                free(e);
 127                                                e = p;
 128                                                p = p->next;
 129                                                psize--;
 130                                        }
 131                                }
 132
 133                                e->next = NULL;
 134
 135                                if (l)
 136                                        l->next = e;
 137                                if (!new_list)
 138                                        new_list = e;
 139                                l = e;
 140                        }
 141
 142                        p = q;
 143                };
 144
 145                k = k * 2;
 146        } while ((last_merge_count != merge_count) || (last_merge_count != 1));
 147
 148        return new_list;
 149}
 150
 151/*
 152 * Future: need to be in "struct repository"
 153 * when doing a full libification.
 154 */
 155static struct cached_refs {
 156        char did_loose;
 157        char did_packed;
 158        struct ref_list *loose;
 159        struct ref_list *packed;
 160} cached_refs;
 161static struct ref_list *current_ref;
 162
 163static struct ref_list *extra_refs;
 164
 165static void free_ref_list(struct ref_list *list)
 166{
 167        struct ref_list *next;
 168        for ( ; list; list = next) {
 169                next = list->next;
 170                free(list);
 171        }
 172}
 173
 174static void invalidate_cached_refs(void)
 175{
 176        struct cached_refs *ca = &cached_refs;
 177
 178        if (ca->did_loose && ca->loose)
 179                free_ref_list(ca->loose);
 180        if (ca->did_packed && ca->packed)
 181                free_ref_list(ca->packed);
 182        ca->loose = ca->packed = NULL;
 183        ca->did_loose = ca->did_packed = 0;
 184}
 185
 186static void read_packed_refs(FILE *f, struct cached_refs *cached_refs)
 187{
 188        struct ref_list *list = NULL;
 189        struct ref_list *last = NULL;
 190        char refline[PATH_MAX];
 191        int flag = REF_ISPACKED;
 192
 193        while (fgets(refline, sizeof(refline), f)) {
 194                unsigned char sha1[20];
 195                const char *name;
 196                static const char header[] = "# pack-refs with:";
 197
 198                if (!strncmp(refline, header, sizeof(header)-1)) {
 199                        const char *traits = refline + sizeof(header) - 1;
 200                        if (strstr(traits, " peeled "))
 201                                flag |= REF_KNOWS_PEELED;
 202                        /* perhaps other traits later as well */
 203                        continue;
 204                }
 205
 206                name = parse_ref_line(refline, sha1);
 207                if (name) {
 208                        list = add_ref(name, sha1, flag, list, &last);
 209                        continue;
 210                }
 211                if (last &&
 212                    refline[0] == '^' &&
 213                    strlen(refline) == 42 &&
 214                    refline[41] == '\n' &&
 215                    !get_sha1_hex(refline + 1, sha1))
 216                        hashcpy(last->peeled, sha1);
 217        }
 218        cached_refs->packed = sort_ref_list(list);
 219}
 220
 221void add_extra_ref(const char *name, const unsigned char *sha1, int flag)
 222{
 223        extra_refs = add_ref(name, sha1, flag, extra_refs, NULL);
 224}
 225
 226void clear_extra_refs(void)
 227{
 228        free_ref_list(extra_refs);
 229        extra_refs = NULL;
 230}
 231
 232static struct ref_list *get_packed_refs(void)
 233{
 234        if (!cached_refs.did_packed) {
 235                FILE *f = fopen(git_path("packed-refs"), "r");
 236                cached_refs.packed = NULL;
 237                if (f) {
 238                        read_packed_refs(f, &cached_refs);
 239                        fclose(f);
 240                }
 241                cached_refs.did_packed = 1;
 242        }
 243        return cached_refs.packed;
 244}
 245
 246static struct ref_list *get_ref_dir(const char *base, struct ref_list *list)
 247{
 248        DIR *dir = opendir(git_path("%s", base));
 249
 250        if (dir) {
 251                struct dirent *de;
 252                int baselen = strlen(base);
 253                char *ref = xmalloc(baselen + 257);
 254
 255                memcpy(ref, base, baselen);
 256                if (baselen && base[baselen-1] != '/')
 257                        ref[baselen++] = '/';
 258
 259                while ((de = readdir(dir)) != NULL) {
 260                        unsigned char sha1[20];
 261                        struct stat st;
 262                        int flag;
 263                        int namelen;
 264
 265                        if (de->d_name[0] == '.')
 266                                continue;
 267                        namelen = strlen(de->d_name);
 268                        if (namelen > 255)
 269                                continue;
 270                        if (has_extension(de->d_name, ".lock"))
 271                                continue;
 272                        memcpy(ref + baselen, de->d_name, namelen+1);
 273                        if (stat(git_path("%s", ref), &st) < 0)
 274                                continue;
 275                        if (S_ISDIR(st.st_mode)) {
 276                                list = get_ref_dir(ref, list);
 277                                continue;
 278                        }
 279                        if (!resolve_ref(ref, sha1, 1, &flag)) {
 280                                hashclr(sha1);
 281                                flag |= REF_BROKEN;
 282                        }
 283                        list = add_ref(ref, sha1, flag, list, NULL);
 284                }
 285                free(ref);
 286                closedir(dir);
 287        }
 288        return sort_ref_list(list);
 289}
 290
 291struct warn_if_dangling_data {
 292        FILE *fp;
 293        const char *refname;
 294        const char *msg_fmt;
 295};
 296
 297static int warn_if_dangling_symref(const char *refname, const unsigned char *sha1,
 298                                   int flags, void *cb_data)
 299{
 300        struct warn_if_dangling_data *d = cb_data;
 301        const char *resolves_to;
 302        unsigned char junk[20];
 303
 304        if (!(flags & REF_ISSYMREF))
 305                return 0;
 306
 307        resolves_to = resolve_ref(refname, junk, 0, NULL);
 308        if (!resolves_to || strcmp(resolves_to, d->refname))
 309                return 0;
 310
 311        fprintf(d->fp, d->msg_fmt, refname);
 312        return 0;
 313}
 314
 315void warn_dangling_symref(FILE *fp, const char *msg_fmt, const char *refname)
 316{
 317        struct warn_if_dangling_data data = { fp, refname, msg_fmt };
 318        for_each_rawref(warn_if_dangling_symref, &data);
 319}
 320
 321static struct ref_list *get_loose_refs(void)
 322{
 323        if (!cached_refs.did_loose) {
 324                cached_refs.loose = get_ref_dir("refs", NULL);
 325                cached_refs.did_loose = 1;
 326        }
 327        return cached_refs.loose;
 328}
 329
 330/* We allow "recursive" symbolic refs. Only within reason, though */
 331#define MAXDEPTH 5
 332#define MAXREFLEN (1024)
 333
 334static int resolve_gitlink_packed_ref(char *name, int pathlen, const char *refname, unsigned char *result)
 335{
 336        FILE *f;
 337        struct cached_refs refs;
 338        struct ref_list *ref;
 339        int retval;
 340
 341        strcpy(name + pathlen, "packed-refs");
 342        f = fopen(name, "r");
 343        if (!f)
 344                return -1;
 345        read_packed_refs(f, &refs);
 346        fclose(f);
 347        ref = refs.packed;
 348        retval = -1;
 349        while (ref) {
 350                if (!strcmp(ref->name, refname)) {
 351                        retval = 0;
 352                        memcpy(result, ref->sha1, 20);
 353                        break;
 354                }
 355                ref = ref->next;
 356        }
 357        free_ref_list(refs.packed);
 358        return retval;
 359}
 360
 361static int resolve_gitlink_ref_recursive(char *name, int pathlen, const char *refname, unsigned char *result, int recursion)
 362{
 363        int fd, len = strlen(refname);
 364        char buffer[128], *p;
 365
 366        if (recursion > MAXDEPTH || len > MAXREFLEN)
 367                return -1;
 368        memcpy(name + pathlen, refname, len+1);
 369        fd = open(name, O_RDONLY);
 370        if (fd < 0)
 371                return resolve_gitlink_packed_ref(name, pathlen, refname, result);
 372
 373        len = read(fd, buffer, sizeof(buffer)-1);
 374        close(fd);
 375        if (len < 0)
 376                return -1;
 377        while (len && isspace(buffer[len-1]))
 378                len--;
 379        buffer[len] = 0;
 380
 381        /* Was it a detached head or an old-fashioned symlink? */
 382        if (!get_sha1_hex(buffer, result))
 383                return 0;
 384
 385        /* Symref? */
 386        if (strncmp(buffer, "ref:", 4))
 387                return -1;
 388        p = buffer + 4;
 389        while (isspace(*p))
 390                p++;
 391
 392        return resolve_gitlink_ref_recursive(name, pathlen, p, result, recursion+1);
 393}
 394
 395int resolve_gitlink_ref(const char *path, const char *refname, unsigned char *result)
 396{
 397        int len = strlen(path), retval;
 398        char *gitdir;
 399        const char *tmp;
 400
 401        while (len && path[len-1] == '/')
 402                len--;
 403        if (!len)
 404                return -1;
 405        gitdir = xmalloc(len + MAXREFLEN + 8);
 406        memcpy(gitdir, path, len);
 407        memcpy(gitdir + len, "/.git", 6);
 408        len += 5;
 409
 410        tmp = read_gitfile_gently(gitdir);
 411        if (tmp) {
 412                free(gitdir);
 413                len = strlen(tmp);
 414                gitdir = xmalloc(len + MAXREFLEN + 3);
 415                memcpy(gitdir, tmp, len);
 416        }
 417        gitdir[len] = '/';
 418        gitdir[++len] = '\0';
 419        retval = resolve_gitlink_ref_recursive(gitdir, len, refname, result, 0);
 420        free(gitdir);
 421        return retval;
 422}
 423
 424/*
 425 * If the "reading" argument is set, this function finds out what _object_
 426 * the ref points at by "reading" the ref.  The ref, if it is not symbolic,
 427 * has to exist, and if it is symbolic, it has to point at an existing ref,
 428 * because the "read" goes through the symref to the ref it points at.
 429 *
 430 * The access that is not "reading" may often be "writing", but does not
 431 * have to; it can be merely checking _where it leads to_. If it is a
 432 * prelude to "writing" to the ref, a write to a symref that points at
 433 * yet-to-be-born ref will create the real ref pointed by the symref.
 434 * reading=0 allows the caller to check where such a symref leads to.
 435 */
 436const char *resolve_ref(const char *ref, unsigned char *sha1, int reading, int *flag)
 437{
 438        int depth = MAXDEPTH;
 439        ssize_t len;
 440        char buffer[256];
 441        static char ref_buffer[256];
 442
 443        if (flag)
 444                *flag = 0;
 445
 446        for (;;) {
 447                char path[PATH_MAX];
 448                struct stat st;
 449                char *buf;
 450                int fd;
 451
 452                if (--depth < 0)
 453                        return NULL;
 454
 455                git_snpath(path, sizeof(path), "%s", ref);
 456                /* Special case: non-existing file. */
 457                if (lstat(path, &st) < 0) {
 458                        struct ref_list *list = get_packed_refs();
 459                        while (list) {
 460                                if (!strcmp(ref, list->name)) {
 461                                        hashcpy(sha1, list->sha1);
 462                                        if (flag)
 463                                                *flag |= REF_ISPACKED;
 464                                        return ref;
 465                                }
 466                                list = list->next;
 467                        }
 468                        if (reading || errno != ENOENT)
 469                                return NULL;
 470                        hashclr(sha1);
 471                        return ref;
 472                }
 473
 474                /* Follow "normalized" - ie "refs/.." symlinks by hand */
 475                if (S_ISLNK(st.st_mode)) {
 476                        len = readlink(path, buffer, sizeof(buffer)-1);
 477                        if (len >= 5 && !memcmp("refs/", buffer, 5)) {
 478                                buffer[len] = 0;
 479                                strcpy(ref_buffer, buffer);
 480                                ref = ref_buffer;
 481                                if (flag)
 482                                        *flag |= REF_ISSYMREF;
 483                                continue;
 484                        }
 485                }
 486
 487                /* Is it a directory? */
 488                if (S_ISDIR(st.st_mode)) {
 489                        errno = EISDIR;
 490                        return NULL;
 491                }
 492
 493                /*
 494                 * Anything else, just open it and try to use it as
 495                 * a ref
 496                 */
 497                fd = open(path, O_RDONLY);
 498                if (fd < 0)
 499                        return NULL;
 500                len = read_in_full(fd, buffer, sizeof(buffer)-1);
 501                close(fd);
 502
 503                /*
 504                 * Is it a symbolic ref?
 505                 */
 506                if (len < 4 || memcmp("ref:", buffer, 4))
 507                        break;
 508                buf = buffer + 4;
 509                len -= 4;
 510                while (len && isspace(*buf))
 511                        buf++, len--;
 512                while (len && isspace(buf[len-1]))
 513                        len--;
 514                buf[len] = 0;
 515                memcpy(ref_buffer, buf, len + 1);
 516                ref = ref_buffer;
 517                if (flag)
 518                        *flag |= REF_ISSYMREF;
 519        }
 520        if (len < 40 || get_sha1_hex(buffer, sha1))
 521                return NULL;
 522        return ref;
 523}
 524
 525/* The argument to filter_refs */
 526struct ref_filter {
 527        const char *pattern;
 528        each_ref_fn *fn;
 529        void *cb_data;
 530};
 531
 532int read_ref(const char *ref, unsigned char *sha1)
 533{
 534        if (resolve_ref(ref, sha1, 1, NULL))
 535                return 0;
 536        return -1;
 537}
 538
 539#define DO_FOR_EACH_INCLUDE_BROKEN 01
 540static int do_one_ref(const char *base, each_ref_fn fn, int trim,
 541                      int flags, void *cb_data, struct ref_list *entry)
 542{
 543        if (strncmp(base, entry->name, trim))
 544                return 0;
 545
 546        if (!(flags & DO_FOR_EACH_INCLUDE_BROKEN)) {
 547                if (entry->flag & REF_BROKEN)
 548                        return 0; /* ignore dangling symref */
 549                if (!has_sha1_file(entry->sha1)) {
 550                        error("%s does not point to a valid object!", entry->name);
 551                        return 0;
 552                }
 553        }
 554        current_ref = entry;
 555        return fn(entry->name + trim, entry->sha1, entry->flag, cb_data);
 556}
 557
 558static int filter_refs(const char *ref, const unsigned char *sha, int flags,
 559        void *data)
 560{
 561        struct ref_filter *filter = (struct ref_filter *)data;
 562        if (fnmatch(filter->pattern, ref, 0))
 563                return 0;
 564        return filter->fn(ref, sha, flags, filter->cb_data);
 565}
 566
 567int peel_ref(const char *ref, unsigned char *sha1)
 568{
 569        int flag;
 570        unsigned char base[20];
 571        struct object *o;
 572
 573        if (current_ref && (current_ref->name == ref
 574                || !strcmp(current_ref->name, ref))) {
 575                if (current_ref->flag & REF_KNOWS_PEELED) {
 576                        hashcpy(sha1, current_ref->peeled);
 577                        return 0;
 578                }
 579                hashcpy(base, current_ref->sha1);
 580                goto fallback;
 581        }
 582
 583        if (!resolve_ref(ref, base, 1, &flag))
 584                return -1;
 585
 586        if ((flag & REF_ISPACKED)) {
 587                struct ref_list *list = get_packed_refs();
 588
 589                while (list) {
 590                        if (!strcmp(list->name, ref)) {
 591                                if (list->flag & REF_KNOWS_PEELED) {
 592                                        hashcpy(sha1, list->peeled);
 593                                        return 0;
 594                                }
 595                                /* older pack-refs did not leave peeled ones */
 596                                break;
 597                        }
 598                        list = list->next;
 599                }
 600        }
 601
 602fallback:
 603        o = parse_object(base);
 604        if (o && o->type == OBJ_TAG) {
 605                o = deref_tag(o, ref, 0);
 606                if (o) {
 607                        hashcpy(sha1, o->sha1);
 608                        return 0;
 609                }
 610        }
 611        return -1;
 612}
 613
 614static int do_for_each_ref(const char *base, each_ref_fn fn, int trim,
 615                           int flags, void *cb_data)
 616{
 617        int retval = 0;
 618        struct ref_list *packed = get_packed_refs();
 619        struct ref_list *loose = get_loose_refs();
 620
 621        struct ref_list *extra;
 622
 623        for (extra = extra_refs; extra; extra = extra->next)
 624                retval = do_one_ref(base, fn, trim, flags, cb_data, extra);
 625
 626        while (packed && loose) {
 627                struct ref_list *entry;
 628                int cmp = strcmp(packed->name, loose->name);
 629                if (!cmp) {
 630                        packed = packed->next;
 631                        continue;
 632                }
 633                if (cmp > 0) {
 634                        entry = loose;
 635                        loose = loose->next;
 636                } else {
 637                        entry = packed;
 638                        packed = packed->next;
 639                }
 640                retval = do_one_ref(base, fn, trim, flags, cb_data, entry);
 641                if (retval)
 642                        goto end_each;
 643        }
 644
 645        for (packed = packed ? packed : loose; packed; packed = packed->next) {
 646                retval = do_one_ref(base, fn, trim, flags, cb_data, packed);
 647                if (retval)
 648                        goto end_each;
 649        }
 650
 651end_each:
 652        current_ref = NULL;
 653        return retval;
 654}
 655
 656int head_ref(each_ref_fn fn, void *cb_data)
 657{
 658        unsigned char sha1[20];
 659        int flag;
 660
 661        if (resolve_ref("HEAD", sha1, 1, &flag))
 662                return fn("HEAD", sha1, flag, cb_data);
 663        return 0;
 664}
 665
 666int for_each_ref(each_ref_fn fn, void *cb_data)
 667{
 668        return do_for_each_ref("refs/", fn, 0, 0, cb_data);
 669}
 670
 671int for_each_ref_in(const char *prefix, each_ref_fn fn, void *cb_data)
 672{
 673        return do_for_each_ref(prefix, fn, strlen(prefix), 0, cb_data);
 674}
 675
 676int for_each_tag_ref(each_ref_fn fn, void *cb_data)
 677{
 678        return for_each_ref_in("refs/tags/", fn, cb_data);
 679}
 680
 681int for_each_branch_ref(each_ref_fn fn, void *cb_data)
 682{
 683        return for_each_ref_in("refs/heads/", fn, cb_data);
 684}
 685
 686int for_each_remote_ref(each_ref_fn fn, void *cb_data)
 687{
 688        return for_each_ref_in("refs/remotes/", fn, cb_data);
 689}
 690
 691int for_each_replace_ref(each_ref_fn fn, void *cb_data)
 692{
 693        return do_for_each_ref("refs/replace/", fn, 13, 0, cb_data);
 694}
 695
 696int for_each_glob_ref_in(each_ref_fn fn, const char *pattern,
 697        const char *prefix, void *cb_data)
 698{
 699        struct strbuf real_pattern = STRBUF_INIT;
 700        struct ref_filter filter;
 701        int ret;
 702
 703        if (!prefix && prefixcmp(pattern, "refs/"))
 704                strbuf_addstr(&real_pattern, "refs/");
 705        else if (prefix)
 706                strbuf_addstr(&real_pattern, prefix);
 707        strbuf_addstr(&real_pattern, pattern);
 708
 709        if (!has_glob_specials(pattern)) {
 710                /* Append implied '/' '*' if not present. */
 711                if (real_pattern.buf[real_pattern.len - 1] != '/')
 712                        strbuf_addch(&real_pattern, '/');
 713                /* No need to check for '*', there is none. */
 714                strbuf_addch(&real_pattern, '*');
 715        }
 716
 717        filter.pattern = real_pattern.buf;
 718        filter.fn = fn;
 719        filter.cb_data = cb_data;
 720        ret = for_each_ref(filter_refs, &filter);
 721
 722        strbuf_release(&real_pattern);
 723        return ret;
 724}
 725
 726int for_each_glob_ref(each_ref_fn fn, const char *pattern, void *cb_data)
 727{
 728        return for_each_glob_ref_in(fn, pattern, NULL, cb_data);
 729}
 730
 731int for_each_rawref(each_ref_fn fn, void *cb_data)
 732{
 733        return do_for_each_ref("refs/", fn, 0,
 734                               DO_FOR_EACH_INCLUDE_BROKEN, cb_data);
 735}
 736
 737/*
 738 * Make sure "ref" is something reasonable to have under ".git/refs/";
 739 * We do not like it if:
 740 *
 741 * - any path component of it begins with ".", or
 742 * - it has double dots "..", or
 743 * - it has ASCII control character, "~", "^", ":" or SP, anywhere, or
 744 * - it ends with a "/".
 745 * - it ends with ".lock"
 746 * - it contains a "\" (backslash)
 747 */
 748
 749static inline int bad_ref_char(int ch)
 750{
 751        if (((unsigned) ch) <= ' ' ||
 752            ch == '~' || ch == '^' || ch == ':' || ch == '\\')
 753                return 1;
 754        /* 2.13 Pattern Matching Notation */
 755        if (ch == '?' || ch == '[') /* Unsupported */
 756                return 1;
 757        if (ch == '*') /* Supported at the end */
 758                return 2;
 759        return 0;
 760}
 761
 762int check_ref_format(const char *ref)
 763{
 764        int ch, level, bad_type, last;
 765        int ret = CHECK_REF_FORMAT_OK;
 766        const char *cp = ref;
 767
 768        level = 0;
 769        while (1) {
 770                while ((ch = *cp++) == '/')
 771                        ; /* tolerate duplicated slashes */
 772                if (!ch)
 773                        /* should not end with slashes */
 774                        return CHECK_REF_FORMAT_ERROR;
 775
 776                /* we are at the beginning of the path component */
 777                if (ch == '.')
 778                        return CHECK_REF_FORMAT_ERROR;
 779                bad_type = bad_ref_char(ch);
 780                if (bad_type) {
 781                        if (bad_type == 2 && (!*cp || *cp == '/') &&
 782                            ret == CHECK_REF_FORMAT_OK)
 783                                ret = CHECK_REF_FORMAT_WILDCARD;
 784                        else
 785                                return CHECK_REF_FORMAT_ERROR;
 786                }
 787
 788                last = ch;
 789                /* scan the rest of the path component */
 790                while ((ch = *cp++) != 0) {
 791                        bad_type = bad_ref_char(ch);
 792                        if (bad_type)
 793                                return CHECK_REF_FORMAT_ERROR;
 794                        if (ch == '/')
 795                                break;
 796                        if (last == '.' && ch == '.')
 797                                return CHECK_REF_FORMAT_ERROR;
 798                        if (last == '@' && ch == '{')
 799                                return CHECK_REF_FORMAT_ERROR;
 800                        last = ch;
 801                }
 802                level++;
 803                if (!ch) {
 804                        if (ref <= cp - 2 && cp[-2] == '.')
 805                                return CHECK_REF_FORMAT_ERROR;
 806                        if (level < 2)
 807                                return CHECK_REF_FORMAT_ONELEVEL;
 808                        if (has_extension(ref, ".lock"))
 809                                return CHECK_REF_FORMAT_ERROR;
 810                        return ret;
 811                }
 812        }
 813}
 814
 815const char *prettify_refname(const char *name)
 816{
 817        return name + (
 818                !prefixcmp(name, "refs/heads/") ? 11 :
 819                !prefixcmp(name, "refs/tags/") ? 10 :
 820                !prefixcmp(name, "refs/remotes/") ? 13 :
 821                0);
 822}
 823
 824const char *ref_rev_parse_rules[] = {
 825        "%.*s",
 826        "refs/%.*s",
 827        "refs/tags/%.*s",
 828        "refs/heads/%.*s",
 829        "refs/remotes/%.*s",
 830        "refs/remotes/%.*s/HEAD",
 831        NULL
 832};
 833
 834const char *ref_fetch_rules[] = {
 835        "%.*s",
 836        "refs/%.*s",
 837        "refs/heads/%.*s",
 838        NULL
 839};
 840
 841int refname_match(const char *abbrev_name, const char *full_name, const char **rules)
 842{
 843        const char **p;
 844        const int abbrev_name_len = strlen(abbrev_name);
 845
 846        for (p = rules; *p; p++) {
 847                if (!strcmp(full_name, mkpath(*p, abbrev_name_len, abbrev_name))) {
 848                        return 1;
 849                }
 850        }
 851
 852        return 0;
 853}
 854
 855static struct ref_lock *verify_lock(struct ref_lock *lock,
 856        const unsigned char *old_sha1, int mustexist)
 857{
 858        if (!resolve_ref(lock->ref_name, lock->old_sha1, mustexist, NULL)) {
 859                error("Can't verify ref %s", lock->ref_name);
 860                unlock_ref(lock);
 861                return NULL;
 862        }
 863        if (hashcmp(lock->old_sha1, old_sha1)) {
 864                error("Ref %s is at %s but expected %s", lock->ref_name,
 865                        sha1_to_hex(lock->old_sha1), sha1_to_hex(old_sha1));
 866                unlock_ref(lock);
 867                return NULL;
 868        }
 869        return lock;
 870}
 871
 872static int remove_empty_directories(const char *file)
 873{
 874        /* we want to create a file but there is a directory there;
 875         * if that is an empty directory (or a directory that contains
 876         * only empty directories), remove them.
 877         */
 878        struct strbuf path;
 879        int result;
 880
 881        strbuf_init(&path, 20);
 882        strbuf_addstr(&path, file);
 883
 884        result = remove_dir_recursively(&path, REMOVE_DIR_EMPTY_ONLY);
 885
 886        strbuf_release(&path);
 887
 888        return result;
 889}
 890
 891static int is_refname_available(const char *ref, const char *oldref,
 892                                struct ref_list *list, int quiet)
 893{
 894        int namlen = strlen(ref); /* e.g. 'foo/bar' */
 895        while (list) {
 896                /* list->name could be 'foo' or 'foo/bar/baz' */
 897                if (!oldref || strcmp(oldref, list->name)) {
 898                        int len = strlen(list->name);
 899                        int cmplen = (namlen < len) ? namlen : len;
 900                        const char *lead = (namlen < len) ? list->name : ref;
 901                        if (!strncmp(ref, list->name, cmplen) &&
 902                            lead[cmplen] == '/') {
 903                                if (!quiet)
 904                                        error("'%s' exists; cannot create '%s'",
 905                                              list->name, ref);
 906                                return 0;
 907                        }
 908                }
 909                list = list->next;
 910        }
 911        return 1;
 912}
 913
 914static struct ref_lock *lock_ref_sha1_basic(const char *ref, const unsigned char *old_sha1, int flags, int *type_p)
 915{
 916        char *ref_file;
 917        const char *orig_ref = ref;
 918        struct ref_lock *lock;
 919        int last_errno = 0;
 920        int type, lflags;
 921        int mustexist = (old_sha1 && !is_null_sha1(old_sha1));
 922        int missing = 0;
 923
 924        lock = xcalloc(1, sizeof(struct ref_lock));
 925        lock->lock_fd = -1;
 926
 927        ref = resolve_ref(ref, lock->old_sha1, mustexist, &type);
 928        if (!ref && errno == EISDIR) {
 929                /* we are trying to lock foo but we used to
 930                 * have foo/bar which now does not exist;
 931                 * it is normal for the empty directory 'foo'
 932                 * to remain.
 933                 */
 934                ref_file = git_path("%s", orig_ref);
 935                if (remove_empty_directories(ref_file)) {
 936                        last_errno = errno;
 937                        error("there are still refs under '%s'", orig_ref);
 938                        goto error_return;
 939                }
 940                ref = resolve_ref(orig_ref, lock->old_sha1, mustexist, &type);
 941        }
 942        if (type_p)
 943            *type_p = type;
 944        if (!ref) {
 945                last_errno = errno;
 946                error("unable to resolve reference %s: %s",
 947                        orig_ref, strerror(errno));
 948                goto error_return;
 949        }
 950        missing = is_null_sha1(lock->old_sha1);
 951        /* When the ref did not exist and we are creating it,
 952         * make sure there is no existing ref that is packed
 953         * whose name begins with our refname, nor a ref whose
 954         * name is a proper prefix of our refname.
 955         */
 956        if (missing &&
 957             !is_refname_available(ref, NULL, get_packed_refs(), 0)) {
 958                last_errno = ENOTDIR;
 959                goto error_return;
 960        }
 961
 962        lock->lk = xcalloc(1, sizeof(struct lock_file));
 963
 964        lflags = LOCK_DIE_ON_ERROR;
 965        if (flags & REF_NODEREF) {
 966                ref = orig_ref;
 967                lflags |= LOCK_NODEREF;
 968        }
 969        lock->ref_name = xstrdup(ref);
 970        lock->orig_ref_name = xstrdup(orig_ref);
 971        ref_file = git_path("%s", ref);
 972        if (missing)
 973                lock->force_write = 1;
 974        if ((flags & REF_NODEREF) && (type & REF_ISSYMREF))
 975                lock->force_write = 1;
 976
 977        if (safe_create_leading_directories(ref_file)) {
 978                last_errno = errno;
 979                error("unable to create directory for %s", ref_file);
 980                goto error_return;
 981        }
 982
 983        lock->lock_fd = hold_lock_file_for_update(lock->lk, ref_file, lflags);
 984        return old_sha1 ? verify_lock(lock, old_sha1, mustexist) : lock;
 985
 986 error_return:
 987        unlock_ref(lock);
 988        errno = last_errno;
 989        return NULL;
 990}
 991
 992struct ref_lock *lock_ref_sha1(const char *ref, const unsigned char *old_sha1)
 993{
 994        char refpath[PATH_MAX];
 995        if (check_ref_format(ref))
 996                return NULL;
 997        strcpy(refpath, mkpath("refs/%s", ref));
 998        return lock_ref_sha1_basic(refpath, old_sha1, 0, NULL);
 999}
1000
1001struct ref_lock *lock_any_ref_for_update(const char *ref, const unsigned char *old_sha1, int flags)
1002{
1003        switch (check_ref_format(ref)) {
1004        default:
1005                return NULL;
1006        case 0:
1007        case CHECK_REF_FORMAT_ONELEVEL:
1008                return lock_ref_sha1_basic(ref, old_sha1, flags, NULL);
1009        }
1010}
1011
1012static struct lock_file packlock;
1013
1014static int repack_without_ref(const char *refname)
1015{
1016        struct ref_list *list, *packed_ref_list;
1017        int fd;
1018        int found = 0;
1019
1020        packed_ref_list = get_packed_refs();
1021        for (list = packed_ref_list; list; list = list->next) {
1022                if (!strcmp(refname, list->name)) {
1023                        found = 1;
1024                        break;
1025                }
1026        }
1027        if (!found)
1028                return 0;
1029        fd = hold_lock_file_for_update(&packlock, git_path("packed-refs"), 0);
1030        if (fd < 0) {
1031                unable_to_lock_error(git_path("packed-refs"), errno);
1032                return error("cannot delete '%s' from packed refs", refname);
1033        }
1034
1035        for (list = packed_ref_list; list; list = list->next) {
1036                char line[PATH_MAX + 100];
1037                int len;
1038
1039                if (!strcmp(refname, list->name))
1040                        continue;
1041                len = snprintf(line, sizeof(line), "%s %s\n",
1042                               sha1_to_hex(list->sha1), list->name);
1043                /* this should not happen but just being defensive */
1044                if (len > sizeof(line))
1045                        die("too long a refname '%s'", list->name);
1046                write_or_die(fd, line, len);
1047        }
1048        return commit_lock_file(&packlock);
1049}
1050
1051int delete_ref(const char *refname, const unsigned char *sha1, int delopt)
1052{
1053        struct ref_lock *lock;
1054        int err, i = 0, ret = 0, flag = 0;
1055
1056        lock = lock_ref_sha1_basic(refname, sha1, 0, &flag);
1057        if (!lock)
1058                return 1;
1059        if (!(flag & REF_ISPACKED) || flag & REF_ISSYMREF) {
1060                /* loose */
1061                const char *path;
1062
1063                if (!(delopt & REF_NODEREF)) {
1064                        i = strlen(lock->lk->filename) - 5; /* .lock */
1065                        lock->lk->filename[i] = 0;
1066                        path = lock->lk->filename;
1067                } else {
1068                        path = git_path("%s", refname);
1069                }
1070                err = unlink_or_warn(path);
1071                if (err && errno != ENOENT)
1072                        ret = 1;
1073
1074                if (!(delopt & REF_NODEREF))
1075                        lock->lk->filename[i] = '.';
1076        }
1077        /* removing the loose one could have resurrected an earlier
1078         * packed one.  Also, if it was not loose we need to repack
1079         * without it.
1080         */
1081        ret |= repack_without_ref(refname);
1082
1083        unlink_or_warn(git_path("logs/%s", lock->ref_name));
1084        invalidate_cached_refs();
1085        unlock_ref(lock);
1086        return ret;
1087}
1088
1089int rename_ref(const char *oldref, const char *newref, const char *logmsg)
1090{
1091        static const char renamed_ref[] = "RENAMED-REF";
1092        unsigned char sha1[20], orig_sha1[20];
1093        int flag = 0, logmoved = 0;
1094        struct ref_lock *lock;
1095        struct stat loginfo;
1096        int log = !lstat(git_path("logs/%s", oldref), &loginfo);
1097        const char *symref = NULL;
1098
1099        if (log && S_ISLNK(loginfo.st_mode))
1100                return error("reflog for %s is a symlink", oldref);
1101
1102        symref = resolve_ref(oldref, orig_sha1, 1, &flag);
1103        if (flag & REF_ISSYMREF)
1104                return error("refname %s is a symbolic ref, renaming it is not supported",
1105                        oldref);
1106        if (!symref)
1107                return error("refname %s not found", oldref);
1108
1109        if (!is_refname_available(newref, oldref, get_packed_refs(), 0))
1110                return 1;
1111
1112        if (!is_refname_available(newref, oldref, get_loose_refs(), 0))
1113                return 1;
1114
1115        lock = lock_ref_sha1_basic(renamed_ref, NULL, 0, NULL);
1116        if (!lock)
1117                return error("unable to lock %s", renamed_ref);
1118        lock->force_write = 1;
1119        if (write_ref_sha1(lock, orig_sha1, logmsg))
1120                return error("unable to save current sha1 in %s", renamed_ref);
1121
1122        if (log && rename(git_path("logs/%s", oldref), git_path("tmp-renamed-log")))
1123                return error("unable to move logfile logs/%s to tmp-renamed-log: %s",
1124                        oldref, strerror(errno));
1125
1126        if (delete_ref(oldref, orig_sha1, REF_NODEREF)) {
1127                error("unable to delete old %s", oldref);
1128                goto rollback;
1129        }
1130
1131        if (resolve_ref(newref, sha1, 1, &flag) && delete_ref(newref, sha1, REF_NODEREF)) {
1132                if (errno==EISDIR) {
1133                        if (remove_empty_directories(git_path("%s", newref))) {
1134                                error("Directory not empty: %s", newref);
1135                                goto rollback;
1136                        }
1137                } else {
1138                        error("unable to delete existing %s", newref);
1139                        goto rollback;
1140                }
1141        }
1142
1143        if (log && safe_create_leading_directories(git_path("logs/%s", newref))) {
1144                error("unable to create directory for %s", newref);
1145                goto rollback;
1146        }
1147
1148 retry:
1149        if (log && rename(git_path("tmp-renamed-log"), git_path("logs/%s", newref))) {
1150                if (errno==EISDIR || errno==ENOTDIR) {
1151                        /*
1152                         * rename(a, b) when b is an existing
1153                         * directory ought to result in ISDIR, but
1154                         * Solaris 5.8 gives ENOTDIR.  Sheesh.
1155                         */
1156                        if (remove_empty_directories(git_path("logs/%s", newref))) {
1157                                error("Directory not empty: logs/%s", newref);
1158                                goto rollback;
1159                        }
1160                        goto retry;
1161                } else {
1162                        error("unable to move logfile tmp-renamed-log to logs/%s: %s",
1163                                newref, strerror(errno));
1164                        goto rollback;
1165                }
1166        }
1167        logmoved = log;
1168
1169        lock = lock_ref_sha1_basic(newref, NULL, 0, NULL);
1170        if (!lock) {
1171                error("unable to lock %s for update", newref);
1172                goto rollback;
1173        }
1174        lock->force_write = 1;
1175        hashcpy(lock->old_sha1, orig_sha1);
1176        if (write_ref_sha1(lock, orig_sha1, logmsg)) {
1177                error("unable to write current sha1 into %s", newref);
1178                goto rollback;
1179        }
1180
1181        return 0;
1182
1183 rollback:
1184        lock = lock_ref_sha1_basic(oldref, NULL, 0, NULL);
1185        if (!lock) {
1186                error("unable to lock %s for rollback", oldref);
1187                goto rollbacklog;
1188        }
1189
1190        lock->force_write = 1;
1191        flag = log_all_ref_updates;
1192        log_all_ref_updates = 0;
1193        if (write_ref_sha1(lock, orig_sha1, NULL))
1194                error("unable to write current sha1 into %s", oldref);
1195        log_all_ref_updates = flag;
1196
1197 rollbacklog:
1198        if (logmoved && rename(git_path("logs/%s", newref), git_path("logs/%s", oldref)))
1199                error("unable to restore logfile %s from %s: %s",
1200                        oldref, newref, strerror(errno));
1201        if (!logmoved && log &&
1202            rename(git_path("tmp-renamed-log"), git_path("logs/%s", oldref)))
1203                error("unable to restore logfile %s from tmp-renamed-log: %s",
1204                        oldref, strerror(errno));
1205
1206        return 1;
1207}
1208
1209int close_ref(struct ref_lock *lock)
1210{
1211        if (close_lock_file(lock->lk))
1212                return -1;
1213        lock->lock_fd = -1;
1214        return 0;
1215}
1216
1217int commit_ref(struct ref_lock *lock)
1218{
1219        if (commit_lock_file(lock->lk))
1220                return -1;
1221        lock->lock_fd = -1;
1222        return 0;
1223}
1224
1225void unlock_ref(struct ref_lock *lock)
1226{
1227        /* Do not free lock->lk -- atexit() still looks at them */
1228        if (lock->lk)
1229                rollback_lock_file(lock->lk);
1230        free(lock->ref_name);
1231        free(lock->orig_ref_name);
1232        free(lock);
1233}
1234
1235/*
1236 * copy the reflog message msg to buf, which has been allocated sufficiently
1237 * large, while cleaning up the whitespaces.  Especially, convert LF to space,
1238 * because reflog file is one line per entry.
1239 */
1240static int copy_msg(char *buf, const char *msg)
1241{
1242        char *cp = buf;
1243        char c;
1244        int wasspace = 1;
1245
1246        *cp++ = '\t';
1247        while ((c = *msg++)) {
1248                if (wasspace && isspace(c))
1249                        continue;
1250                wasspace = isspace(c);
1251                if (wasspace)
1252                        c = ' ';
1253                *cp++ = c;
1254        }
1255        while (buf < cp && isspace(cp[-1]))
1256                cp--;
1257        *cp++ = '\n';
1258        return cp - buf;
1259}
1260
1261static int log_ref_write(const char *ref_name, const unsigned char *old_sha1,
1262                         const unsigned char *new_sha1, const char *msg)
1263{
1264        int logfd, written, oflags = O_APPEND | O_WRONLY;
1265        unsigned maxlen, len;
1266        int msglen;
1267        char log_file[PATH_MAX];
1268        char *logrec;
1269        const char *committer;
1270
1271        if (log_all_ref_updates < 0)
1272                log_all_ref_updates = !is_bare_repository();
1273
1274        git_snpath(log_file, sizeof(log_file), "logs/%s", ref_name);
1275
1276        if (log_all_ref_updates &&
1277            (!prefixcmp(ref_name, "refs/heads/") ||
1278             !prefixcmp(ref_name, "refs/remotes/") ||
1279             !prefixcmp(ref_name, "refs/notes/") ||
1280             !strcmp(ref_name, "HEAD"))) {
1281                if (safe_create_leading_directories(log_file) < 0)
1282                        return error("unable to create directory for %s",
1283                                     log_file);
1284                oflags |= O_CREAT;
1285        }
1286
1287        logfd = open(log_file, oflags, 0666);
1288        if (logfd < 0) {
1289                if (!(oflags & O_CREAT) && errno == ENOENT)
1290                        return 0;
1291
1292                if ((oflags & O_CREAT) && errno == EISDIR) {
1293                        if (remove_empty_directories(log_file)) {
1294                                return error("There are still logs under '%s'",
1295                                             log_file);
1296                        }
1297                        logfd = open(log_file, oflags, 0666);
1298                }
1299
1300                if (logfd < 0)
1301                        return error("Unable to append to %s: %s",
1302                                     log_file, strerror(errno));
1303        }
1304
1305        adjust_shared_perm(log_file);
1306
1307        msglen = msg ? strlen(msg) : 0;
1308        committer = git_committer_info(0);
1309        maxlen = strlen(committer) + msglen + 100;
1310        logrec = xmalloc(maxlen);
1311        len = sprintf(logrec, "%s %s %s\n",
1312                      sha1_to_hex(old_sha1),
1313                      sha1_to_hex(new_sha1),
1314                      committer);
1315        if (msglen)
1316                len += copy_msg(logrec + len - 1, msg) - 1;
1317        written = len <= maxlen ? write_in_full(logfd, logrec, len) : -1;
1318        free(logrec);
1319        if (close(logfd) != 0 || written != len)
1320                return error("Unable to append to %s", log_file);
1321        return 0;
1322}
1323
1324static int is_branch(const char *refname)
1325{
1326        return !strcmp(refname, "HEAD") || !prefixcmp(refname, "refs/heads/");
1327}
1328
1329int write_ref_sha1(struct ref_lock *lock,
1330        const unsigned char *sha1, const char *logmsg)
1331{
1332        static char term = '\n';
1333        struct object *o;
1334
1335        if (!lock)
1336                return -1;
1337        if (!lock->force_write && !hashcmp(lock->old_sha1, sha1)) {
1338                unlock_ref(lock);
1339                return 0;
1340        }
1341        o = parse_object(sha1);
1342        if (!o) {
1343                error("Trying to write ref %s with nonexistant object %s",
1344                        lock->ref_name, sha1_to_hex(sha1));
1345                unlock_ref(lock);
1346                return -1;
1347        }
1348        if (o->type != OBJ_COMMIT && is_branch(lock->ref_name)) {
1349                error("Trying to write non-commit object %s to branch %s",
1350                        sha1_to_hex(sha1), lock->ref_name);
1351                unlock_ref(lock);
1352                return -1;
1353        }
1354        if (write_in_full(lock->lock_fd, sha1_to_hex(sha1), 40) != 40 ||
1355            write_in_full(lock->lock_fd, &term, 1) != 1
1356                || close_ref(lock) < 0) {
1357                error("Couldn't write %s", lock->lk->filename);
1358                unlock_ref(lock);
1359                return -1;
1360        }
1361        invalidate_cached_refs();
1362        if (log_ref_write(lock->ref_name, lock->old_sha1, sha1, logmsg) < 0 ||
1363            (strcmp(lock->ref_name, lock->orig_ref_name) &&
1364             log_ref_write(lock->orig_ref_name, lock->old_sha1, sha1, logmsg) < 0)) {
1365                unlock_ref(lock);
1366                return -1;
1367        }
1368        if (strcmp(lock->orig_ref_name, "HEAD") != 0) {
1369                /*
1370                 * Special hack: If a branch is updated directly and HEAD
1371                 * points to it (may happen on the remote side of a push
1372                 * for example) then logically the HEAD reflog should be
1373                 * updated too.
1374                 * A generic solution implies reverse symref information,
1375                 * but finding all symrefs pointing to the given branch
1376                 * would be rather costly for this rare event (the direct
1377                 * update of a branch) to be worth it.  So let's cheat and
1378                 * check with HEAD only which should cover 99% of all usage
1379                 * scenarios (even 100% of the default ones).
1380                 */
1381                unsigned char head_sha1[20];
1382                int head_flag;
1383                const char *head_ref;
1384                head_ref = resolve_ref("HEAD", head_sha1, 1, &head_flag);
1385                if (head_ref && (head_flag & REF_ISSYMREF) &&
1386                    !strcmp(head_ref, lock->ref_name))
1387                        log_ref_write("HEAD", lock->old_sha1, sha1, logmsg);
1388        }
1389        if (commit_ref(lock)) {
1390                error("Couldn't set %s", lock->ref_name);
1391                unlock_ref(lock);
1392                return -1;
1393        }
1394        unlock_ref(lock);
1395        return 0;
1396}
1397
1398int create_symref(const char *ref_target, const char *refs_heads_master,
1399                  const char *logmsg)
1400{
1401        const char *lockpath;
1402        char ref[1000];
1403        int fd, len, written;
1404        char *git_HEAD = git_pathdup("%s", ref_target);
1405        unsigned char old_sha1[20], new_sha1[20];
1406
1407        if (logmsg && read_ref(ref_target, old_sha1))
1408                hashclr(old_sha1);
1409
1410        if (safe_create_leading_directories(git_HEAD) < 0)
1411                return error("unable to create directory for %s", git_HEAD);
1412
1413#ifndef NO_SYMLINK_HEAD
1414        if (prefer_symlink_refs) {
1415                unlink(git_HEAD);
1416                if (!symlink(refs_heads_master, git_HEAD))
1417                        goto done;
1418                fprintf(stderr, "no symlink - falling back to symbolic ref\n");
1419        }
1420#endif
1421
1422        len = snprintf(ref, sizeof(ref), "ref: %s\n", refs_heads_master);
1423        if (sizeof(ref) <= len) {
1424                error("refname too long: %s", refs_heads_master);
1425                goto error_free_return;
1426        }
1427        lockpath = mkpath("%s.lock", git_HEAD);
1428        fd = open(lockpath, O_CREAT | O_EXCL | O_WRONLY, 0666);
1429        if (fd < 0) {
1430                error("Unable to open %s for writing", lockpath);
1431                goto error_free_return;
1432        }
1433        written = write_in_full(fd, ref, len);
1434        if (close(fd) != 0 || written != len) {
1435                error("Unable to write to %s", lockpath);
1436                goto error_unlink_return;
1437        }
1438        if (rename(lockpath, git_HEAD) < 0) {
1439                error("Unable to create %s", git_HEAD);
1440                goto error_unlink_return;
1441        }
1442        if (adjust_shared_perm(git_HEAD)) {
1443                error("Unable to fix permissions on %s", lockpath);
1444        error_unlink_return:
1445                unlink_or_warn(lockpath);
1446        error_free_return:
1447                free(git_HEAD);
1448                return -1;
1449        }
1450
1451#ifndef NO_SYMLINK_HEAD
1452        done:
1453#endif
1454        if (logmsg && !read_ref(refs_heads_master, new_sha1))
1455                log_ref_write(ref_target, old_sha1, new_sha1, logmsg);
1456
1457        free(git_HEAD);
1458        return 0;
1459}
1460
1461static char *ref_msg(const char *line, const char *endp)
1462{
1463        const char *ep;
1464        line += 82;
1465        ep = memchr(line, '\n', endp - line);
1466        if (!ep)
1467                ep = endp;
1468        return xmemdupz(line, ep - line);
1469}
1470
1471int 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)
1472{
1473        const char *logfile, *logdata, *logend, *rec, *lastgt, *lastrec;
1474        char *tz_c;
1475        int logfd, tz, reccnt = 0;
1476        struct stat st;
1477        unsigned long date;
1478        unsigned char logged_sha1[20];
1479        void *log_mapped;
1480        size_t mapsz;
1481
1482        logfile = git_path("logs/%s", ref);
1483        logfd = open(logfile, O_RDONLY, 0);
1484        if (logfd < 0)
1485                die_errno("Unable to read log '%s'", logfile);
1486        fstat(logfd, &st);
1487        if (!st.st_size)
1488                die("Log %s is empty.", logfile);
1489        mapsz = xsize_t(st.st_size);
1490        log_mapped = xmmap(NULL, mapsz, PROT_READ, MAP_PRIVATE, logfd, 0);
1491        logdata = log_mapped;
1492        close(logfd);
1493
1494        lastrec = NULL;
1495        rec = logend = logdata + st.st_size;
1496        while (logdata < rec) {
1497                reccnt++;
1498                if (logdata < rec && *(rec-1) == '\n')
1499                        rec--;
1500                lastgt = NULL;
1501                while (logdata < rec && *(rec-1) != '\n') {
1502                        rec--;
1503                        if (*rec == '>')
1504                                lastgt = rec;
1505                }
1506                if (!lastgt)
1507                        die("Log %s is corrupt.", logfile);
1508                date = strtoul(lastgt + 1, &tz_c, 10);
1509                if (date <= at_time || cnt == 0) {
1510                        tz = strtoul(tz_c, NULL, 10);
1511                        if (msg)
1512                                *msg = ref_msg(rec, logend);
1513                        if (cutoff_time)
1514                                *cutoff_time = date;
1515                        if (cutoff_tz)
1516                                *cutoff_tz = tz;
1517                        if (cutoff_cnt)
1518                                *cutoff_cnt = reccnt - 1;
1519                        if (lastrec) {
1520                                if (get_sha1_hex(lastrec, logged_sha1))
1521                                        die("Log %s is corrupt.", logfile);
1522                                if (get_sha1_hex(rec + 41, sha1))
1523                                        die("Log %s is corrupt.", logfile);
1524                                if (hashcmp(logged_sha1, sha1)) {
1525                                        warning("Log %s has gap after %s.",
1526                                                logfile, show_date(date, tz, DATE_RFC2822));
1527                                }
1528                        }
1529                        else if (date == at_time) {
1530                                if (get_sha1_hex(rec + 41, sha1))
1531                                        die("Log %s is corrupt.", logfile);
1532                        }
1533                        else {
1534                                if (get_sha1_hex(rec + 41, logged_sha1))
1535                                        die("Log %s is corrupt.", logfile);
1536                                if (hashcmp(logged_sha1, sha1)) {
1537                                        warning("Log %s unexpectedly ended on %s.",
1538                                                logfile, show_date(date, tz, DATE_RFC2822));
1539                                }
1540                        }
1541                        munmap(log_mapped, mapsz);
1542                        return 0;
1543                }
1544                lastrec = rec;
1545                if (cnt > 0)
1546                        cnt--;
1547        }
1548
1549        rec = logdata;
1550        while (rec < logend && *rec != '>' && *rec != '\n')
1551                rec++;
1552        if (rec == logend || *rec == '\n')
1553                die("Log %s is corrupt.", logfile);
1554        date = strtoul(rec + 1, &tz_c, 10);
1555        tz = strtoul(tz_c, NULL, 10);
1556        if (get_sha1_hex(logdata, sha1))
1557                die("Log %s is corrupt.", logfile);
1558        if (is_null_sha1(sha1)) {
1559                if (get_sha1_hex(logdata + 41, sha1))
1560                        die("Log %s is corrupt.", logfile);
1561        }
1562        if (msg)
1563                *msg = ref_msg(logdata, logend);
1564        munmap(log_mapped, mapsz);
1565
1566        if (cutoff_time)
1567                *cutoff_time = date;
1568        if (cutoff_tz)
1569                *cutoff_tz = tz;
1570        if (cutoff_cnt)
1571                *cutoff_cnt = reccnt;
1572        return 1;
1573}
1574
1575int for_each_recent_reflog_ent(const char *ref, each_reflog_ent_fn fn, long ofs, void *cb_data)
1576{
1577        const char *logfile;
1578        FILE *logfp;
1579        struct strbuf sb = STRBUF_INIT;
1580        int ret = 0;
1581
1582        logfile = git_path("logs/%s", ref);
1583        logfp = fopen(logfile, "r");
1584        if (!logfp)
1585                return -1;
1586
1587        if (ofs) {
1588                struct stat statbuf;
1589                if (fstat(fileno(logfp), &statbuf) ||
1590                    statbuf.st_size < ofs ||
1591                    fseek(logfp, -ofs, SEEK_END) ||
1592                    strbuf_getwholeline(&sb, logfp, '\n')) {
1593                        fclose(logfp);
1594                        strbuf_release(&sb);
1595                        return -1;
1596                }
1597        }
1598
1599        while (!strbuf_getwholeline(&sb, logfp, '\n')) {
1600                unsigned char osha1[20], nsha1[20];
1601                char *email_end, *message;
1602                unsigned long timestamp;
1603                int tz;
1604
1605                /* old SP new SP name <email> SP time TAB msg LF */
1606                if (sb.len < 83 || sb.buf[sb.len - 1] != '\n' ||
1607                    get_sha1_hex(sb.buf, osha1) || sb.buf[40] != ' ' ||
1608                    get_sha1_hex(sb.buf + 41, nsha1) || sb.buf[81] != ' ' ||
1609                    !(email_end = strchr(sb.buf + 82, '>')) ||
1610                    email_end[1] != ' ' ||
1611                    !(timestamp = strtoul(email_end + 2, &message, 10)) ||
1612                    !message || message[0] != ' ' ||
1613                    (message[1] != '+' && message[1] != '-') ||
1614                    !isdigit(message[2]) || !isdigit(message[3]) ||
1615                    !isdigit(message[4]) || !isdigit(message[5]))
1616                        continue; /* corrupt? */
1617                email_end[1] = '\0';
1618                tz = strtol(message + 1, NULL, 10);
1619                if (message[6] != '\t')
1620                        message += 6;
1621                else
1622                        message += 7;
1623                ret = fn(osha1, nsha1, sb.buf + 82, timestamp, tz, message,
1624                         cb_data);
1625                if (ret)
1626                        break;
1627        }
1628        fclose(logfp);
1629        strbuf_release(&sb);
1630        return ret;
1631}
1632
1633int for_each_reflog_ent(const char *ref, each_reflog_ent_fn fn, void *cb_data)
1634{
1635        return for_each_recent_reflog_ent(ref, fn, 0, cb_data);
1636}
1637
1638static int do_for_each_reflog(const char *base, each_ref_fn fn, void *cb_data)
1639{
1640        DIR *dir = opendir(git_path("logs/%s", base));
1641        int retval = 0;
1642
1643        if (dir) {
1644                struct dirent *de;
1645                int baselen = strlen(base);
1646                char *log = xmalloc(baselen + 257);
1647
1648                memcpy(log, base, baselen);
1649                if (baselen && base[baselen-1] != '/')
1650                        log[baselen++] = '/';
1651
1652                while ((de = readdir(dir)) != NULL) {
1653                        struct stat st;
1654                        int namelen;
1655
1656                        if (de->d_name[0] == '.')
1657                                continue;
1658                        namelen = strlen(de->d_name);
1659                        if (namelen > 255)
1660                                continue;
1661                        if (has_extension(de->d_name, ".lock"))
1662                                continue;
1663                        memcpy(log + baselen, de->d_name, namelen+1);
1664                        if (stat(git_path("logs/%s", log), &st) < 0)
1665                                continue;
1666                        if (S_ISDIR(st.st_mode)) {
1667                                retval = do_for_each_reflog(log, fn, cb_data);
1668                        } else {
1669                                unsigned char sha1[20];
1670                                if (!resolve_ref(log, sha1, 0, NULL))
1671                                        retval = error("bad ref for %s", log);
1672                                else
1673                                        retval = fn(log, sha1, 0, cb_data);
1674                        }
1675                        if (retval)
1676                                break;
1677                }
1678                free(log);
1679                closedir(dir);
1680        }
1681        else if (*base)
1682                return errno;
1683        return retval;
1684}
1685
1686int for_each_reflog(each_ref_fn fn, void *cb_data)
1687{
1688        return do_for_each_reflog("", fn, cb_data);
1689}
1690
1691int update_ref(const char *action, const char *refname,
1692                const unsigned char *sha1, const unsigned char *oldval,
1693                int flags, enum action_on_err onerr)
1694{
1695        static struct ref_lock *lock;
1696        lock = lock_any_ref_for_update(refname, oldval, flags);
1697        if (!lock) {
1698                const char *str = "Cannot lock the ref '%s'.";
1699                switch (onerr) {
1700                case MSG_ON_ERR: error(str, refname); break;
1701                case DIE_ON_ERR: die(str, refname); break;
1702                case QUIET_ON_ERR: break;
1703                }
1704                return 1;
1705        }
1706        if (write_ref_sha1(lock, sha1, action) < 0) {
1707                const char *str = "Cannot update the ref '%s'.";
1708                switch (onerr) {
1709                case MSG_ON_ERR: error(str, refname); break;
1710                case DIE_ON_ERR: die(str, refname); break;
1711                case QUIET_ON_ERR: break;
1712                }
1713                return 1;
1714        }
1715        return 0;
1716}
1717
1718struct ref *find_ref_by_name(const struct ref *list, const char *name)
1719{
1720        for ( ; list; list = list->next)
1721                if (!strcmp(list->name, name))
1722                        return (struct ref *)list;
1723        return NULL;
1724}
1725
1726/*
1727 * generate a format suitable for scanf from a ref_rev_parse_rules
1728 * rule, that is replace the "%.*s" spec with a "%s" spec
1729 */
1730static void gen_scanf_fmt(char *scanf_fmt, const char *rule)
1731{
1732        char *spec;
1733
1734        spec = strstr(rule, "%.*s");
1735        if (!spec || strstr(spec + 4, "%.*s"))
1736                die("invalid rule in ref_rev_parse_rules: %s", rule);
1737
1738        /* copy all until spec */
1739        strncpy(scanf_fmt, rule, spec - rule);
1740        scanf_fmt[spec - rule] = '\0';
1741        /* copy new spec */
1742        strcat(scanf_fmt, "%s");
1743        /* copy remaining rule */
1744        strcat(scanf_fmt, spec + 4);
1745
1746        return;
1747}
1748
1749char *shorten_unambiguous_ref(const char *ref, int strict)
1750{
1751        int i;
1752        static char **scanf_fmts;
1753        static int nr_rules;
1754        char *short_name;
1755
1756        /* pre generate scanf formats from ref_rev_parse_rules[] */
1757        if (!nr_rules) {
1758                size_t total_len = 0;
1759
1760                /* the rule list is NULL terminated, count them first */
1761                for (; ref_rev_parse_rules[nr_rules]; nr_rules++)
1762                        /* no +1 because strlen("%s") < strlen("%.*s") */
1763                        total_len += strlen(ref_rev_parse_rules[nr_rules]);
1764
1765                scanf_fmts = xmalloc(nr_rules * sizeof(char *) + total_len);
1766
1767                total_len = 0;
1768                for (i = 0; i < nr_rules; i++) {
1769                        scanf_fmts[i] = (char *)&scanf_fmts[nr_rules]
1770                                        + total_len;
1771                        gen_scanf_fmt(scanf_fmts[i], ref_rev_parse_rules[i]);
1772                        total_len += strlen(ref_rev_parse_rules[i]);
1773                }
1774        }
1775
1776        /* bail out if there are no rules */
1777        if (!nr_rules)
1778                return xstrdup(ref);
1779
1780        /* buffer for scanf result, at most ref must fit */
1781        short_name = xstrdup(ref);
1782
1783        /* skip first rule, it will always match */
1784        for (i = nr_rules - 1; i > 0 ; --i) {
1785                int j;
1786                int rules_to_fail = i;
1787                int short_name_len;
1788
1789                if (1 != sscanf(ref, scanf_fmts[i], short_name))
1790                        continue;
1791
1792                short_name_len = strlen(short_name);
1793
1794                /*
1795                 * in strict mode, all (except the matched one) rules
1796                 * must fail to resolve to a valid non-ambiguous ref
1797                 */
1798                if (strict)
1799                        rules_to_fail = nr_rules;
1800
1801                /*
1802                 * check if the short name resolves to a valid ref,
1803                 * but use only rules prior to the matched one
1804                 */
1805                for (j = 0; j < rules_to_fail; j++) {
1806                        const char *rule = ref_rev_parse_rules[j];
1807                        unsigned char short_objectname[20];
1808                        char refname[PATH_MAX];
1809
1810                        /* skip matched rule */
1811                        if (i == j)
1812                                continue;
1813
1814                        /*
1815                         * the short name is ambiguous, if it resolves
1816                         * (with this previous rule) to a valid ref
1817                         * read_ref() returns 0 on success
1818                         */
1819                        mksnpath(refname, sizeof(refname),
1820                                 rule, short_name_len, short_name);
1821                        if (!read_ref(refname, short_objectname))
1822                                break;
1823                }
1824
1825                /*
1826                 * short name is non-ambiguous if all previous rules
1827                 * haven't resolved to a valid ref
1828                 */
1829                if (j == rules_to_fail)
1830                        return short_name;
1831        }
1832
1833        free(short_name);
1834        return xstrdup(ref);
1835}