refs.con commit Merge branch 'ac/describe-dirty-refresh' (22f6578)
   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, submodule_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(const char *submodule)
 233{
 234        const char *packed_refs_file;
 235        struct cached_refs *refs;
 236
 237        if (submodule) {
 238                packed_refs_file = git_path_submodule(submodule, "packed-refs");
 239                refs = &submodule_refs;
 240                free_ref_list(refs->packed);
 241        } else {
 242                packed_refs_file = git_path("packed-refs");
 243                refs = &cached_refs;
 244        }
 245
 246        if (!refs->did_packed || submodule) {
 247                FILE *f = fopen(packed_refs_file, "r");
 248                refs->packed = NULL;
 249                if (f) {
 250                        read_packed_refs(f, refs);
 251                        fclose(f);
 252                }
 253                refs->did_packed = 1;
 254        }
 255        return refs->packed;
 256}
 257
 258static struct ref_list *get_ref_dir(const char *submodule, const char *base,
 259                                    struct ref_list *list)
 260{
 261        DIR *dir;
 262        const char *path;
 263
 264        if (submodule)
 265                path = git_path_submodule(submodule, "%s", base);
 266        else
 267                path = git_path("%s", base);
 268
 269
 270        dir = opendir(path);
 271
 272        if (dir) {
 273                struct dirent *de;
 274                int baselen = strlen(base);
 275                char *ref = xmalloc(baselen + 257);
 276
 277                memcpy(ref, base, baselen);
 278                if (baselen && base[baselen-1] != '/')
 279                        ref[baselen++] = '/';
 280
 281                while ((de = readdir(dir)) != NULL) {
 282                        unsigned char sha1[20];
 283                        struct stat st;
 284                        int flag;
 285                        int namelen;
 286                        const char *refdir;
 287
 288                        if (de->d_name[0] == '.')
 289                                continue;
 290                        namelen = strlen(de->d_name);
 291                        if (namelen > 255)
 292                                continue;
 293                        if (has_extension(de->d_name, ".lock"))
 294                                continue;
 295                        memcpy(ref + baselen, de->d_name, namelen+1);
 296                        refdir = submodule
 297                                ? git_path_submodule(submodule, "%s", ref)
 298                                : git_path("%s", ref);
 299                        if (stat(refdir, &st) < 0)
 300                                continue;
 301                        if (S_ISDIR(st.st_mode)) {
 302                                list = get_ref_dir(submodule, ref, list);
 303                                continue;
 304                        }
 305                        if (submodule) {
 306                                hashclr(sha1);
 307                                flag = 0;
 308                                if (resolve_gitlink_ref(submodule, ref, sha1) < 0) {
 309                                        hashclr(sha1);
 310                                        flag |= REF_BROKEN;
 311                                }
 312                        } else
 313                                if (!resolve_ref(ref, sha1, 1, &flag)) {
 314                                        hashclr(sha1);
 315                                        flag |= REF_BROKEN;
 316                                }
 317                        list = add_ref(ref, sha1, flag, list, NULL);
 318                }
 319                free(ref);
 320                closedir(dir);
 321        }
 322        return sort_ref_list(list);
 323}
 324
 325struct warn_if_dangling_data {
 326        FILE *fp;
 327        const char *refname;
 328        const char *msg_fmt;
 329};
 330
 331static int warn_if_dangling_symref(const char *refname, const unsigned char *sha1,
 332                                   int flags, void *cb_data)
 333{
 334        struct warn_if_dangling_data *d = cb_data;
 335        const char *resolves_to;
 336        unsigned char junk[20];
 337
 338        if (!(flags & REF_ISSYMREF))
 339                return 0;
 340
 341        resolves_to = resolve_ref(refname, junk, 0, NULL);
 342        if (!resolves_to || strcmp(resolves_to, d->refname))
 343                return 0;
 344
 345        fprintf(d->fp, d->msg_fmt, refname);
 346        return 0;
 347}
 348
 349void warn_dangling_symref(FILE *fp, const char *msg_fmt, const char *refname)
 350{
 351        struct warn_if_dangling_data data;
 352
 353        data.fp = fp;
 354        data.refname = refname;
 355        data.msg_fmt = msg_fmt;
 356        for_each_rawref(warn_if_dangling_symref, &data);
 357}
 358
 359static struct ref_list *get_loose_refs(const char *submodule)
 360{
 361        if (submodule) {
 362                free_ref_list(submodule_refs.loose);
 363                submodule_refs.loose = get_ref_dir(submodule, "refs", NULL);
 364                return submodule_refs.loose;
 365        }
 366
 367        if (!cached_refs.did_loose) {
 368                cached_refs.loose = get_ref_dir(NULL, "refs", NULL);
 369                cached_refs.did_loose = 1;
 370        }
 371        return cached_refs.loose;
 372}
 373
 374/* We allow "recursive" symbolic refs. Only within reason, though */
 375#define MAXDEPTH 5
 376#define MAXREFLEN (1024)
 377
 378static int resolve_gitlink_packed_ref(char *name, int pathlen, const char *refname, unsigned char *result)
 379{
 380        FILE *f;
 381        struct cached_refs refs;
 382        struct ref_list *ref;
 383        int retval;
 384
 385        strcpy(name + pathlen, "packed-refs");
 386        f = fopen(name, "r");
 387        if (!f)
 388                return -1;
 389        read_packed_refs(f, &refs);
 390        fclose(f);
 391        ref = refs.packed;
 392        retval = -1;
 393        while (ref) {
 394                if (!strcmp(ref->name, refname)) {
 395                        retval = 0;
 396                        memcpy(result, ref->sha1, 20);
 397                        break;
 398                }
 399                ref = ref->next;
 400        }
 401        free_ref_list(refs.packed);
 402        return retval;
 403}
 404
 405static int resolve_gitlink_ref_recursive(char *name, int pathlen, const char *refname, unsigned char *result, int recursion)
 406{
 407        int fd, len = strlen(refname);
 408        char buffer[128], *p;
 409
 410        if (recursion > MAXDEPTH || len > MAXREFLEN)
 411                return -1;
 412        memcpy(name + pathlen, refname, len+1);
 413        fd = open(name, O_RDONLY);
 414        if (fd < 0)
 415                return resolve_gitlink_packed_ref(name, pathlen, refname, result);
 416
 417        len = read(fd, buffer, sizeof(buffer)-1);
 418        close(fd);
 419        if (len < 0)
 420                return -1;
 421        while (len && isspace(buffer[len-1]))
 422                len--;
 423        buffer[len] = 0;
 424
 425        /* Was it a detached head or an old-fashioned symlink? */
 426        if (!get_sha1_hex(buffer, result))
 427                return 0;
 428
 429        /* Symref? */
 430        if (strncmp(buffer, "ref:", 4))
 431                return -1;
 432        p = buffer + 4;
 433        while (isspace(*p))
 434                p++;
 435
 436        return resolve_gitlink_ref_recursive(name, pathlen, p, result, recursion+1);
 437}
 438
 439int resolve_gitlink_ref(const char *path, const char *refname, unsigned char *result)
 440{
 441        int len = strlen(path), retval;
 442        char *gitdir;
 443        const char *tmp;
 444
 445        while (len && path[len-1] == '/')
 446                len--;
 447        if (!len)
 448                return -1;
 449        gitdir = xmalloc(len + MAXREFLEN + 8);
 450        memcpy(gitdir, path, len);
 451        memcpy(gitdir + len, "/.git", 6);
 452        len += 5;
 453
 454        tmp = read_gitfile_gently(gitdir);
 455        if (tmp) {
 456                free(gitdir);
 457                len = strlen(tmp);
 458                gitdir = xmalloc(len + MAXREFLEN + 3);
 459                memcpy(gitdir, tmp, len);
 460        }
 461        gitdir[len] = '/';
 462        gitdir[++len] = '\0';
 463        retval = resolve_gitlink_ref_recursive(gitdir, len, refname, result, 0);
 464        free(gitdir);
 465        return retval;
 466}
 467
 468/*
 469 * If the "reading" argument is set, this function finds out what _object_
 470 * the ref points at by "reading" the ref.  The ref, if it is not symbolic,
 471 * has to exist, and if it is symbolic, it has to point at an existing ref,
 472 * because the "read" goes through the symref to the ref it points at.
 473 *
 474 * The access that is not "reading" may often be "writing", but does not
 475 * have to; it can be merely checking _where it leads to_. If it is a
 476 * prelude to "writing" to the ref, a write to a symref that points at
 477 * yet-to-be-born ref will create the real ref pointed by the symref.
 478 * reading=0 allows the caller to check where such a symref leads to.
 479 */
 480const char *resolve_ref(const char *ref, unsigned char *sha1, int reading, int *flag)
 481{
 482        int depth = MAXDEPTH;
 483        ssize_t len;
 484        char buffer[256];
 485        static char ref_buffer[256];
 486
 487        if (flag)
 488                *flag = 0;
 489
 490        for (;;) {
 491                char path[PATH_MAX];
 492                struct stat st;
 493                char *buf;
 494                int fd;
 495
 496                if (--depth < 0)
 497                        return NULL;
 498
 499                git_snpath(path, sizeof(path), "%s", ref);
 500                /* Special case: non-existing file. */
 501                if (lstat(path, &st) < 0) {
 502                        struct ref_list *list = get_packed_refs(NULL);
 503                        while (list) {
 504                                if (!strcmp(ref, list->name)) {
 505                                        hashcpy(sha1, list->sha1);
 506                                        if (flag)
 507                                                *flag |= REF_ISPACKED;
 508                                        return ref;
 509                                }
 510                                list = list->next;
 511                        }
 512                        if (reading || errno != ENOENT)
 513                                return NULL;
 514                        hashclr(sha1);
 515                        return ref;
 516                }
 517
 518                /* Follow "normalized" - ie "refs/.." symlinks by hand */
 519                if (S_ISLNK(st.st_mode)) {
 520                        len = readlink(path, buffer, sizeof(buffer)-1);
 521                        if (len >= 5 && !memcmp("refs/", buffer, 5)) {
 522                                buffer[len] = 0;
 523                                strcpy(ref_buffer, buffer);
 524                                ref = ref_buffer;
 525                                if (flag)
 526                                        *flag |= REF_ISSYMREF;
 527                                continue;
 528                        }
 529                }
 530
 531                /* Is it a directory? */
 532                if (S_ISDIR(st.st_mode)) {
 533                        errno = EISDIR;
 534                        return NULL;
 535                }
 536
 537                /*
 538                 * Anything else, just open it and try to use it as
 539                 * a ref
 540                 */
 541                fd = open(path, O_RDONLY);
 542                if (fd < 0)
 543                        return NULL;
 544                len = read_in_full(fd, buffer, sizeof(buffer)-1);
 545                close(fd);
 546
 547                /*
 548                 * Is it a symbolic ref?
 549                 */
 550                if (len < 4 || memcmp("ref:", buffer, 4))
 551                        break;
 552                buf = buffer + 4;
 553                len -= 4;
 554                while (len && isspace(*buf))
 555                        buf++, len--;
 556                while (len && isspace(buf[len-1]))
 557                        len--;
 558                buf[len] = 0;
 559                memcpy(ref_buffer, buf, len + 1);
 560                ref = ref_buffer;
 561                if (flag)
 562                        *flag |= REF_ISSYMREF;
 563        }
 564        if (len < 40 || get_sha1_hex(buffer, sha1))
 565                return NULL;
 566        return ref;
 567}
 568
 569/* The argument to filter_refs */
 570struct ref_filter {
 571        const char *pattern;
 572        each_ref_fn *fn;
 573        void *cb_data;
 574};
 575
 576int read_ref(const char *ref, unsigned char *sha1)
 577{
 578        if (resolve_ref(ref, sha1, 1, NULL))
 579                return 0;
 580        return -1;
 581}
 582
 583#define DO_FOR_EACH_INCLUDE_BROKEN 01
 584static int do_one_ref(const char *base, each_ref_fn fn, int trim,
 585                      int flags, void *cb_data, struct ref_list *entry)
 586{
 587        if (prefixcmp(entry->name, base))
 588                return 0;
 589
 590        if (!(flags & DO_FOR_EACH_INCLUDE_BROKEN)) {
 591                if (entry->flag & REF_BROKEN)
 592                        return 0; /* ignore dangling symref */
 593                if (!has_sha1_file(entry->sha1)) {
 594                        error("%s does not point to a valid object!", entry->name);
 595                        return 0;
 596                }
 597        }
 598        current_ref = entry;
 599        return fn(entry->name + trim, entry->sha1, entry->flag, cb_data);
 600}
 601
 602static int filter_refs(const char *ref, const unsigned char *sha, int flags,
 603        void *data)
 604{
 605        struct ref_filter *filter = (struct ref_filter *)data;
 606        if (fnmatch(filter->pattern, ref, 0))
 607                return 0;
 608        return filter->fn(ref, sha, flags, filter->cb_data);
 609}
 610
 611int peel_ref(const char *ref, unsigned char *sha1)
 612{
 613        int flag;
 614        unsigned char base[20];
 615        struct object *o;
 616
 617        if (current_ref && (current_ref->name == ref
 618                || !strcmp(current_ref->name, ref))) {
 619                if (current_ref->flag & REF_KNOWS_PEELED) {
 620                        hashcpy(sha1, current_ref->peeled);
 621                        return 0;
 622                }
 623                hashcpy(base, current_ref->sha1);
 624                goto fallback;
 625        }
 626
 627        if (!resolve_ref(ref, base, 1, &flag))
 628                return -1;
 629
 630        if ((flag & REF_ISPACKED)) {
 631                struct ref_list *list = get_packed_refs(NULL);
 632
 633                while (list) {
 634                        if (!strcmp(list->name, ref)) {
 635                                if (list->flag & REF_KNOWS_PEELED) {
 636                                        hashcpy(sha1, list->peeled);
 637                                        return 0;
 638                                }
 639                                /* older pack-refs did not leave peeled ones */
 640                                break;
 641                        }
 642                        list = list->next;
 643                }
 644        }
 645
 646fallback:
 647        o = parse_object(base);
 648        if (o && o->type == OBJ_TAG) {
 649                o = deref_tag(o, ref, 0);
 650                if (o) {
 651                        hashcpy(sha1, o->sha1);
 652                        return 0;
 653                }
 654        }
 655        return -1;
 656}
 657
 658static int do_for_each_ref(const char *submodule, const char *base, each_ref_fn fn,
 659                           int trim, int flags, void *cb_data)
 660{
 661        int retval = 0;
 662        struct ref_list *packed = get_packed_refs(submodule);
 663        struct ref_list *loose = get_loose_refs(submodule);
 664
 665        struct ref_list *extra;
 666
 667        for (extra = extra_refs; extra; extra = extra->next)
 668                retval = do_one_ref(base, fn, trim, flags, cb_data, extra);
 669
 670        while (packed && loose) {
 671                struct ref_list *entry;
 672                int cmp = strcmp(packed->name, loose->name);
 673                if (!cmp) {
 674                        packed = packed->next;
 675                        continue;
 676                }
 677                if (cmp > 0) {
 678                        entry = loose;
 679                        loose = loose->next;
 680                } else {
 681                        entry = packed;
 682                        packed = packed->next;
 683                }
 684                retval = do_one_ref(base, fn, trim, flags, cb_data, entry);
 685                if (retval)
 686                        goto end_each;
 687        }
 688
 689        for (packed = packed ? packed : loose; packed; packed = packed->next) {
 690                retval = do_one_ref(base, fn, trim, flags, cb_data, packed);
 691                if (retval)
 692                        goto end_each;
 693        }
 694
 695end_each:
 696        current_ref = NULL;
 697        return retval;
 698}
 699
 700
 701static int do_head_ref(const char *submodule, each_ref_fn fn, void *cb_data)
 702{
 703        unsigned char sha1[20];
 704        int flag;
 705
 706        if (submodule) {
 707                if (resolve_gitlink_ref(submodule, "HEAD", sha1) == 0)
 708                        return fn("HEAD", sha1, 0, cb_data);
 709
 710                return 0;
 711        }
 712
 713        if (resolve_ref("HEAD", sha1, 1, &flag))
 714                return fn("HEAD", sha1, flag, cb_data);
 715
 716        return 0;
 717}
 718
 719int head_ref(each_ref_fn fn, void *cb_data)
 720{
 721        return do_head_ref(NULL, fn, cb_data);
 722}
 723
 724int head_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
 725{
 726        return do_head_ref(submodule, fn, cb_data);
 727}
 728
 729int for_each_ref(each_ref_fn fn, void *cb_data)
 730{
 731        return do_for_each_ref(NULL, "", fn, 0, 0, cb_data);
 732}
 733
 734int for_each_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
 735{
 736        return do_for_each_ref(submodule, "", fn, 0, 0, cb_data);
 737}
 738
 739int for_each_ref_in(const char *prefix, each_ref_fn fn, void *cb_data)
 740{
 741        return do_for_each_ref(NULL, prefix, fn, strlen(prefix), 0, cb_data);
 742}
 743
 744int for_each_ref_in_submodule(const char *submodule, const char *prefix,
 745                each_ref_fn fn, void *cb_data)
 746{
 747        return do_for_each_ref(submodule, prefix, fn, strlen(prefix), 0, cb_data);
 748}
 749
 750int for_each_tag_ref(each_ref_fn fn, void *cb_data)
 751{
 752        return for_each_ref_in("refs/tags/", fn, cb_data);
 753}
 754
 755int for_each_tag_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
 756{
 757        return for_each_ref_in_submodule(submodule, "refs/tags/", fn, cb_data);
 758}
 759
 760int for_each_branch_ref(each_ref_fn fn, void *cb_data)
 761{
 762        return for_each_ref_in("refs/heads/", fn, cb_data);
 763}
 764
 765int for_each_branch_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
 766{
 767        return for_each_ref_in_submodule(submodule, "refs/heads/", fn, cb_data);
 768}
 769
 770int for_each_remote_ref(each_ref_fn fn, void *cb_data)
 771{
 772        return for_each_ref_in("refs/remotes/", fn, cb_data);
 773}
 774
 775int for_each_remote_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
 776{
 777        return for_each_ref_in_submodule(submodule, "refs/remotes/", fn, cb_data);
 778}
 779
 780int for_each_replace_ref(each_ref_fn fn, void *cb_data)
 781{
 782        return do_for_each_ref(NULL, "refs/replace/", fn, 13, 0, cb_data);
 783}
 784
 785int head_ref_namespaced(each_ref_fn fn, void *cb_data)
 786{
 787        struct strbuf buf = STRBUF_INIT;
 788        int ret = 0;
 789        unsigned char sha1[20];
 790        int flag;
 791
 792        strbuf_addf(&buf, "%sHEAD", get_git_namespace());
 793        if (resolve_ref(buf.buf, sha1, 1, &flag))
 794                ret = fn(buf.buf, sha1, flag, cb_data);
 795        strbuf_release(&buf);
 796
 797        return ret;
 798}
 799
 800int for_each_namespaced_ref(each_ref_fn fn, void *cb_data)
 801{
 802        struct strbuf buf = STRBUF_INIT;
 803        int ret;
 804        strbuf_addf(&buf, "%srefs/", get_git_namespace());
 805        ret = do_for_each_ref(NULL, buf.buf, fn, 0, 0, cb_data);
 806        strbuf_release(&buf);
 807        return ret;
 808}
 809
 810int for_each_glob_ref_in(each_ref_fn fn, const char *pattern,
 811        const char *prefix, void *cb_data)
 812{
 813        struct strbuf real_pattern = STRBUF_INIT;
 814        struct ref_filter filter;
 815        int ret;
 816
 817        if (!prefix && prefixcmp(pattern, "refs/"))
 818                strbuf_addstr(&real_pattern, "refs/");
 819        else if (prefix)
 820                strbuf_addstr(&real_pattern, prefix);
 821        strbuf_addstr(&real_pattern, pattern);
 822
 823        if (!has_glob_specials(pattern)) {
 824                /* Append implied '/' '*' if not present. */
 825                if (real_pattern.buf[real_pattern.len - 1] != '/')
 826                        strbuf_addch(&real_pattern, '/');
 827                /* No need to check for '*', there is none. */
 828                strbuf_addch(&real_pattern, '*');
 829        }
 830
 831        filter.pattern = real_pattern.buf;
 832        filter.fn = fn;
 833        filter.cb_data = cb_data;
 834        ret = for_each_ref(filter_refs, &filter);
 835
 836        strbuf_release(&real_pattern);
 837        return ret;
 838}
 839
 840int for_each_glob_ref(each_ref_fn fn, const char *pattern, void *cb_data)
 841{
 842        return for_each_glob_ref_in(fn, pattern, NULL, cb_data);
 843}
 844
 845int for_each_rawref(each_ref_fn fn, void *cb_data)
 846{
 847        return do_for_each_ref(NULL, "", fn, 0,
 848                               DO_FOR_EACH_INCLUDE_BROKEN, cb_data);
 849}
 850
 851/*
 852 * Make sure "ref" is something reasonable to have under ".git/refs/";
 853 * We do not like it if:
 854 *
 855 * - any path component of it begins with ".", or
 856 * - it has double dots "..", or
 857 * - it has ASCII control character, "~", "^", ":" or SP, anywhere, or
 858 * - it ends with a "/".
 859 * - it ends with ".lock"
 860 * - it contains a "\" (backslash)
 861 */
 862
 863static inline int bad_ref_char(int ch)
 864{
 865        if (((unsigned) ch) <= ' ' ||
 866            ch == '~' || ch == '^' || ch == ':' || ch == '\\')
 867                return 1;
 868        /* 2.13 Pattern Matching Notation */
 869        if (ch == '?' || ch == '[') /* Unsupported */
 870                return 1;
 871        if (ch == '*') /* Supported at the end */
 872                return 2;
 873        return 0;
 874}
 875
 876int check_ref_format(const char *ref)
 877{
 878        int ch, level, bad_type, last;
 879        int ret = CHECK_REF_FORMAT_OK;
 880        const char *cp = ref;
 881
 882        level = 0;
 883        while (1) {
 884                while ((ch = *cp++) == '/')
 885                        ; /* tolerate duplicated slashes */
 886                if (!ch)
 887                        /* should not end with slashes */
 888                        return CHECK_REF_FORMAT_ERROR;
 889
 890                /* we are at the beginning of the path component */
 891                if (ch == '.')
 892                        return CHECK_REF_FORMAT_ERROR;
 893                bad_type = bad_ref_char(ch);
 894                if (bad_type) {
 895                        if (bad_type == 2 && (!*cp || *cp == '/') &&
 896                            ret == CHECK_REF_FORMAT_OK)
 897                                ret = CHECK_REF_FORMAT_WILDCARD;
 898                        else
 899                                return CHECK_REF_FORMAT_ERROR;
 900                }
 901
 902                last = ch;
 903                /* scan the rest of the path component */
 904                while ((ch = *cp++) != 0) {
 905                        bad_type = bad_ref_char(ch);
 906                        if (bad_type)
 907                                return CHECK_REF_FORMAT_ERROR;
 908                        if (ch == '/')
 909                                break;
 910                        if (last == '.' && ch == '.')
 911                                return CHECK_REF_FORMAT_ERROR;
 912                        if (last == '@' && ch == '{')
 913                                return CHECK_REF_FORMAT_ERROR;
 914                        last = ch;
 915                }
 916                level++;
 917                if (!ch) {
 918                        if (ref <= cp - 2 && cp[-2] == '.')
 919                                return CHECK_REF_FORMAT_ERROR;
 920                        if (level < 2)
 921                                return CHECK_REF_FORMAT_ONELEVEL;
 922                        if (has_extension(ref, ".lock"))
 923                                return CHECK_REF_FORMAT_ERROR;
 924                        return ret;
 925                }
 926        }
 927}
 928
 929const char *prettify_refname(const char *name)
 930{
 931        return name + (
 932                !prefixcmp(name, "refs/heads/") ? 11 :
 933                !prefixcmp(name, "refs/tags/") ? 10 :
 934                !prefixcmp(name, "refs/remotes/") ? 13 :
 935                0);
 936}
 937
 938const char *ref_rev_parse_rules[] = {
 939        "%.*s",
 940        "refs/%.*s",
 941        "refs/tags/%.*s",
 942        "refs/heads/%.*s",
 943        "refs/remotes/%.*s",
 944        "refs/remotes/%.*s/HEAD",
 945        NULL
 946};
 947
 948const char *ref_fetch_rules[] = {
 949        "%.*s",
 950        "refs/%.*s",
 951        "refs/heads/%.*s",
 952        NULL
 953};
 954
 955int refname_match(const char *abbrev_name, const char *full_name, const char **rules)
 956{
 957        const char **p;
 958        const int abbrev_name_len = strlen(abbrev_name);
 959
 960        for (p = rules; *p; p++) {
 961                if (!strcmp(full_name, mkpath(*p, abbrev_name_len, abbrev_name))) {
 962                        return 1;
 963                }
 964        }
 965
 966        return 0;
 967}
 968
 969static struct ref_lock *verify_lock(struct ref_lock *lock,
 970        const unsigned char *old_sha1, int mustexist)
 971{
 972        if (!resolve_ref(lock->ref_name, lock->old_sha1, mustexist, NULL)) {
 973                error("Can't verify ref %s", lock->ref_name);
 974                unlock_ref(lock);
 975                return NULL;
 976        }
 977        if (hashcmp(lock->old_sha1, old_sha1)) {
 978                error("Ref %s is at %s but expected %s", lock->ref_name,
 979                        sha1_to_hex(lock->old_sha1), sha1_to_hex(old_sha1));
 980                unlock_ref(lock);
 981                return NULL;
 982        }
 983        return lock;
 984}
 985
 986static int remove_empty_directories(const char *file)
 987{
 988        /* we want to create a file but there is a directory there;
 989         * if that is an empty directory (or a directory that contains
 990         * only empty directories), remove them.
 991         */
 992        struct strbuf path;
 993        int result;
 994
 995        strbuf_init(&path, 20);
 996        strbuf_addstr(&path, file);
 997
 998        result = remove_dir_recursively(&path, REMOVE_DIR_EMPTY_ONLY);
 999
1000        strbuf_release(&path);
1001
1002        return result;
1003}
1004
1005static int is_refname_available(const char *ref, const char *oldref,
1006                                struct ref_list *list, int quiet)
1007{
1008        int namlen = strlen(ref); /* e.g. 'foo/bar' */
1009        while (list) {
1010                /* list->name could be 'foo' or 'foo/bar/baz' */
1011                if (!oldref || strcmp(oldref, list->name)) {
1012                        int len = strlen(list->name);
1013                        int cmplen = (namlen < len) ? namlen : len;
1014                        const char *lead = (namlen < len) ? list->name : ref;
1015                        if (!strncmp(ref, list->name, cmplen) &&
1016                            lead[cmplen] == '/') {
1017                                if (!quiet)
1018                                        error("'%s' exists; cannot create '%s'",
1019                                              list->name, ref);
1020                                return 0;
1021                        }
1022                }
1023                list = list->next;
1024        }
1025        return 1;
1026}
1027
1028static struct ref_lock *lock_ref_sha1_basic(const char *ref, const unsigned char *old_sha1, int flags, int *type_p)
1029{
1030        char *ref_file;
1031        const char *orig_ref = ref;
1032        struct ref_lock *lock;
1033        int last_errno = 0;
1034        int type, lflags;
1035        int mustexist = (old_sha1 && !is_null_sha1(old_sha1));
1036        int missing = 0;
1037
1038        lock = xcalloc(1, sizeof(struct ref_lock));
1039        lock->lock_fd = -1;
1040
1041        ref = resolve_ref(ref, lock->old_sha1, mustexist, &type);
1042        if (!ref && errno == EISDIR) {
1043                /* we are trying to lock foo but we used to
1044                 * have foo/bar which now does not exist;
1045                 * it is normal for the empty directory 'foo'
1046                 * to remain.
1047                 */
1048                ref_file = git_path("%s", orig_ref);
1049                if (remove_empty_directories(ref_file)) {
1050                        last_errno = errno;
1051                        error("there are still refs under '%s'", orig_ref);
1052                        goto error_return;
1053                }
1054                ref = resolve_ref(orig_ref, lock->old_sha1, mustexist, &type);
1055        }
1056        if (type_p)
1057            *type_p = type;
1058        if (!ref) {
1059                last_errno = errno;
1060                error("unable to resolve reference %s: %s",
1061                        orig_ref, strerror(errno));
1062                goto error_return;
1063        }
1064        missing = is_null_sha1(lock->old_sha1);
1065        /* When the ref did not exist and we are creating it,
1066         * make sure there is no existing ref that is packed
1067         * whose name begins with our refname, nor a ref whose
1068         * name is a proper prefix of our refname.
1069         */
1070        if (missing &&
1071             !is_refname_available(ref, NULL, get_packed_refs(NULL), 0)) {
1072                last_errno = ENOTDIR;
1073                goto error_return;
1074        }
1075
1076        lock->lk = xcalloc(1, sizeof(struct lock_file));
1077
1078        lflags = LOCK_DIE_ON_ERROR;
1079        if (flags & REF_NODEREF) {
1080                ref = orig_ref;
1081                lflags |= LOCK_NODEREF;
1082        }
1083        lock->ref_name = xstrdup(ref);
1084        lock->orig_ref_name = xstrdup(orig_ref);
1085        ref_file = git_path("%s", ref);
1086        if (missing)
1087                lock->force_write = 1;
1088        if ((flags & REF_NODEREF) && (type & REF_ISSYMREF))
1089                lock->force_write = 1;
1090
1091        if (safe_create_leading_directories(ref_file)) {
1092                last_errno = errno;
1093                error("unable to create directory for %s", ref_file);
1094                goto error_return;
1095        }
1096
1097        lock->lock_fd = hold_lock_file_for_update(lock->lk, ref_file, lflags);
1098        return old_sha1 ? verify_lock(lock, old_sha1, mustexist) : lock;
1099
1100 error_return:
1101        unlock_ref(lock);
1102        errno = last_errno;
1103        return NULL;
1104}
1105
1106struct ref_lock *lock_ref_sha1(const char *ref, const unsigned char *old_sha1)
1107{
1108        char refpath[PATH_MAX];
1109        if (check_ref_format(ref))
1110                return NULL;
1111        strcpy(refpath, mkpath("refs/%s", ref));
1112        return lock_ref_sha1_basic(refpath, old_sha1, 0, NULL);
1113}
1114
1115struct ref_lock *lock_any_ref_for_update(const char *ref, const unsigned char *old_sha1, int flags)
1116{
1117        switch (check_ref_format(ref)) {
1118        default:
1119                return NULL;
1120        case 0:
1121        case CHECK_REF_FORMAT_ONELEVEL:
1122                return lock_ref_sha1_basic(ref, old_sha1, flags, NULL);
1123        }
1124}
1125
1126static struct lock_file packlock;
1127
1128static int repack_without_ref(const char *refname)
1129{
1130        struct ref_list *list, *packed_ref_list;
1131        int fd;
1132        int found = 0;
1133
1134        packed_ref_list = get_packed_refs(NULL);
1135        for (list = packed_ref_list; list; list = list->next) {
1136                if (!strcmp(refname, list->name)) {
1137                        found = 1;
1138                        break;
1139                }
1140        }
1141        if (!found)
1142                return 0;
1143        fd = hold_lock_file_for_update(&packlock, git_path("packed-refs"), 0);
1144        if (fd < 0) {
1145                unable_to_lock_error(git_path("packed-refs"), errno);
1146                return error("cannot delete '%s' from packed refs", refname);
1147        }
1148
1149        for (list = packed_ref_list; list; list = list->next) {
1150                char line[PATH_MAX + 100];
1151                int len;
1152
1153                if (!strcmp(refname, list->name))
1154                        continue;
1155                len = snprintf(line, sizeof(line), "%s %s\n",
1156                               sha1_to_hex(list->sha1), list->name);
1157                /* this should not happen but just being defensive */
1158                if (len > sizeof(line))
1159                        die("too long a refname '%s'", list->name);
1160                write_or_die(fd, line, len);
1161        }
1162        return commit_lock_file(&packlock);
1163}
1164
1165int delete_ref(const char *refname, const unsigned char *sha1, int delopt)
1166{
1167        struct ref_lock *lock;
1168        int err, i = 0, ret = 0, flag = 0;
1169
1170        lock = lock_ref_sha1_basic(refname, sha1, 0, &flag);
1171        if (!lock)
1172                return 1;
1173        if (!(flag & REF_ISPACKED) || flag & REF_ISSYMREF) {
1174                /* loose */
1175                const char *path;
1176
1177                if (!(delopt & REF_NODEREF)) {
1178                        i = strlen(lock->lk->filename) - 5; /* .lock */
1179                        lock->lk->filename[i] = 0;
1180                        path = lock->lk->filename;
1181                } else {
1182                        path = git_path("%s", refname);
1183                }
1184                err = unlink_or_warn(path);
1185                if (err && errno != ENOENT)
1186                        ret = 1;
1187
1188                if (!(delopt & REF_NODEREF))
1189                        lock->lk->filename[i] = '.';
1190        }
1191        /* removing the loose one could have resurrected an earlier
1192         * packed one.  Also, if it was not loose we need to repack
1193         * without it.
1194         */
1195        ret |= repack_without_ref(refname);
1196
1197        unlink_or_warn(git_path("logs/%s", lock->ref_name));
1198        invalidate_cached_refs();
1199        unlock_ref(lock);
1200        return ret;
1201}
1202
1203/*
1204 * People using contrib's git-new-workdir have .git/logs/refs ->
1205 * /some/other/path/.git/logs/refs, and that may live on another device.
1206 *
1207 * IOW, to avoid cross device rename errors, the temporary renamed log must
1208 * live into logs/refs.
1209 */
1210#define TMP_RENAMED_LOG  "logs/refs/.tmp-renamed-log"
1211
1212int rename_ref(const char *oldref, const char *newref, const char *logmsg)
1213{
1214        static const char renamed_ref[] = "RENAMED-REF";
1215        unsigned char sha1[20], orig_sha1[20];
1216        int flag = 0, logmoved = 0;
1217        struct ref_lock *lock;
1218        struct stat loginfo;
1219        int log = !lstat(git_path("logs/%s", oldref), &loginfo);
1220        const char *symref = NULL;
1221
1222        if (log && S_ISLNK(loginfo.st_mode))
1223                return error("reflog for %s is a symlink", oldref);
1224
1225        symref = resolve_ref(oldref, orig_sha1, 1, &flag);
1226        if (flag & REF_ISSYMREF)
1227                return error("refname %s is a symbolic ref, renaming it is not supported",
1228                        oldref);
1229        if (!symref)
1230                return error("refname %s not found", oldref);
1231
1232        if (!is_refname_available(newref, oldref, get_packed_refs(NULL), 0))
1233                return 1;
1234
1235        if (!is_refname_available(newref, oldref, get_loose_refs(NULL), 0))
1236                return 1;
1237
1238        lock = lock_ref_sha1_basic(renamed_ref, NULL, 0, NULL);
1239        if (!lock)
1240                return error("unable to lock %s", renamed_ref);
1241        lock->force_write = 1;
1242        if (write_ref_sha1(lock, orig_sha1, logmsg))
1243                return error("unable to save current sha1 in %s", renamed_ref);
1244
1245        if (log && rename(git_path("logs/%s", oldref), git_path(TMP_RENAMED_LOG)))
1246                return error("unable to move logfile logs/%s to "TMP_RENAMED_LOG": %s",
1247                        oldref, strerror(errno));
1248
1249        if (delete_ref(oldref, orig_sha1, REF_NODEREF)) {
1250                error("unable to delete old %s", oldref);
1251                goto rollback;
1252        }
1253
1254        if (resolve_ref(newref, sha1, 1, &flag) && delete_ref(newref, sha1, REF_NODEREF)) {
1255                if (errno==EISDIR) {
1256                        if (remove_empty_directories(git_path("%s", newref))) {
1257                                error("Directory not empty: %s", newref);
1258                                goto rollback;
1259                        }
1260                } else {
1261                        error("unable to delete existing %s", newref);
1262                        goto rollback;
1263                }
1264        }
1265
1266        if (log && safe_create_leading_directories(git_path("logs/%s", newref))) {
1267                error("unable to create directory for %s", newref);
1268                goto rollback;
1269        }
1270
1271 retry:
1272        if (log && rename(git_path(TMP_RENAMED_LOG), git_path("logs/%s", newref))) {
1273                if (errno==EISDIR || errno==ENOTDIR) {
1274                        /*
1275                         * rename(a, b) when b is an existing
1276                         * directory ought to result in ISDIR, but
1277                         * Solaris 5.8 gives ENOTDIR.  Sheesh.
1278                         */
1279                        if (remove_empty_directories(git_path("logs/%s", newref))) {
1280                                error("Directory not empty: logs/%s", newref);
1281                                goto rollback;
1282                        }
1283                        goto retry;
1284                } else {
1285                        error("unable to move logfile "TMP_RENAMED_LOG" to logs/%s: %s",
1286                                newref, strerror(errno));
1287                        goto rollback;
1288                }
1289        }
1290        logmoved = log;
1291
1292        lock = lock_ref_sha1_basic(newref, NULL, 0, NULL);
1293        if (!lock) {
1294                error("unable to lock %s for update", newref);
1295                goto rollback;
1296        }
1297        lock->force_write = 1;
1298        hashcpy(lock->old_sha1, orig_sha1);
1299        if (write_ref_sha1(lock, orig_sha1, logmsg)) {
1300                error("unable to write current sha1 into %s", newref);
1301                goto rollback;
1302        }
1303
1304        return 0;
1305
1306 rollback:
1307        lock = lock_ref_sha1_basic(oldref, NULL, 0, NULL);
1308        if (!lock) {
1309                error("unable to lock %s for rollback", oldref);
1310                goto rollbacklog;
1311        }
1312
1313        lock->force_write = 1;
1314        flag = log_all_ref_updates;
1315        log_all_ref_updates = 0;
1316        if (write_ref_sha1(lock, orig_sha1, NULL))
1317                error("unable to write current sha1 into %s", oldref);
1318        log_all_ref_updates = flag;
1319
1320 rollbacklog:
1321        if (logmoved && rename(git_path("logs/%s", newref), git_path("logs/%s", oldref)))
1322                error("unable to restore logfile %s from %s: %s",
1323                        oldref, newref, strerror(errno));
1324        if (!logmoved && log &&
1325            rename(git_path(TMP_RENAMED_LOG), git_path("logs/%s", oldref)))
1326                error("unable to restore logfile %s from "TMP_RENAMED_LOG": %s",
1327                        oldref, strerror(errno));
1328
1329        return 1;
1330}
1331
1332int close_ref(struct ref_lock *lock)
1333{
1334        if (close_lock_file(lock->lk))
1335                return -1;
1336        lock->lock_fd = -1;
1337        return 0;
1338}
1339
1340int commit_ref(struct ref_lock *lock)
1341{
1342        if (commit_lock_file(lock->lk))
1343                return -1;
1344        lock->lock_fd = -1;
1345        return 0;
1346}
1347
1348void unlock_ref(struct ref_lock *lock)
1349{
1350        /* Do not free lock->lk -- atexit() still looks at them */
1351        if (lock->lk)
1352                rollback_lock_file(lock->lk);
1353        free(lock->ref_name);
1354        free(lock->orig_ref_name);
1355        free(lock);
1356}
1357
1358/*
1359 * copy the reflog message msg to buf, which has been allocated sufficiently
1360 * large, while cleaning up the whitespaces.  Especially, convert LF to space,
1361 * because reflog file is one line per entry.
1362 */
1363static int copy_msg(char *buf, const char *msg)
1364{
1365        char *cp = buf;
1366        char c;
1367        int wasspace = 1;
1368
1369        *cp++ = '\t';
1370        while ((c = *msg++)) {
1371                if (wasspace && isspace(c))
1372                        continue;
1373                wasspace = isspace(c);
1374                if (wasspace)
1375                        c = ' ';
1376                *cp++ = c;
1377        }
1378        while (buf < cp && isspace(cp[-1]))
1379                cp--;
1380        *cp++ = '\n';
1381        return cp - buf;
1382}
1383
1384int log_ref_setup(const char *ref_name, char *logfile, int bufsize)
1385{
1386        int logfd, oflags = O_APPEND | O_WRONLY;
1387
1388        git_snpath(logfile, bufsize, "logs/%s", ref_name);
1389        if (log_all_ref_updates &&
1390            (!prefixcmp(ref_name, "refs/heads/") ||
1391             !prefixcmp(ref_name, "refs/remotes/") ||
1392             !prefixcmp(ref_name, "refs/notes/") ||
1393             !strcmp(ref_name, "HEAD"))) {
1394                if (safe_create_leading_directories(logfile) < 0)
1395                        return error("unable to create directory for %s",
1396                                     logfile);
1397                oflags |= O_CREAT;
1398        }
1399
1400        logfd = open(logfile, oflags, 0666);
1401        if (logfd < 0) {
1402                if (!(oflags & O_CREAT) && errno == ENOENT)
1403                        return 0;
1404
1405                if ((oflags & O_CREAT) && errno == EISDIR) {
1406                        if (remove_empty_directories(logfile)) {
1407                                return error("There are still logs under '%s'",
1408                                             logfile);
1409                        }
1410                        logfd = open(logfile, oflags, 0666);
1411                }
1412
1413                if (logfd < 0)
1414                        return error("Unable to append to %s: %s",
1415                                     logfile, strerror(errno));
1416        }
1417
1418        adjust_shared_perm(logfile);
1419        close(logfd);
1420        return 0;
1421}
1422
1423static int log_ref_write(const char *ref_name, const unsigned char *old_sha1,
1424                         const unsigned char *new_sha1, const char *msg)
1425{
1426        int logfd, result, written, oflags = O_APPEND | O_WRONLY;
1427        unsigned maxlen, len;
1428        int msglen;
1429        char log_file[PATH_MAX];
1430        char *logrec;
1431        const char *committer;
1432
1433        if (log_all_ref_updates < 0)
1434                log_all_ref_updates = !is_bare_repository();
1435
1436        result = log_ref_setup(ref_name, log_file, sizeof(log_file));
1437        if (result)
1438                return result;
1439
1440        logfd = open(log_file, oflags);
1441        if (logfd < 0)
1442                return 0;
1443        msglen = msg ? strlen(msg) : 0;
1444        committer = git_committer_info(0);
1445        maxlen = strlen(committer) + msglen + 100;
1446        logrec = xmalloc(maxlen);
1447        len = sprintf(logrec, "%s %s %s\n",
1448                      sha1_to_hex(old_sha1),
1449                      sha1_to_hex(new_sha1),
1450                      committer);
1451        if (msglen)
1452                len += copy_msg(logrec + len - 1, msg) - 1;
1453        written = len <= maxlen ? write_in_full(logfd, logrec, len) : -1;
1454        free(logrec);
1455        if (close(logfd) != 0 || written != len)
1456                return error("Unable to append to %s", log_file);
1457        return 0;
1458}
1459
1460static int is_branch(const char *refname)
1461{
1462        return !strcmp(refname, "HEAD") || !prefixcmp(refname, "refs/heads/");
1463}
1464
1465int write_ref_sha1(struct ref_lock *lock,
1466        const unsigned char *sha1, const char *logmsg)
1467{
1468        static char term = '\n';
1469        struct object *o;
1470
1471        if (!lock)
1472                return -1;
1473        if (!lock->force_write && !hashcmp(lock->old_sha1, sha1)) {
1474                unlock_ref(lock);
1475                return 0;
1476        }
1477        o = parse_object(sha1);
1478        if (!o) {
1479                error("Trying to write ref %s with nonexistent object %s",
1480                        lock->ref_name, sha1_to_hex(sha1));
1481                unlock_ref(lock);
1482                return -1;
1483        }
1484        if (o->type != OBJ_COMMIT && is_branch(lock->ref_name)) {
1485                error("Trying to write non-commit object %s to branch %s",
1486                        sha1_to_hex(sha1), lock->ref_name);
1487                unlock_ref(lock);
1488                return -1;
1489        }
1490        if (write_in_full(lock->lock_fd, sha1_to_hex(sha1), 40) != 40 ||
1491            write_in_full(lock->lock_fd, &term, 1) != 1
1492                || close_ref(lock) < 0) {
1493                error("Couldn't write %s", lock->lk->filename);
1494                unlock_ref(lock);
1495                return -1;
1496        }
1497        invalidate_cached_refs();
1498        if (log_ref_write(lock->ref_name, lock->old_sha1, sha1, logmsg) < 0 ||
1499            (strcmp(lock->ref_name, lock->orig_ref_name) &&
1500             log_ref_write(lock->orig_ref_name, lock->old_sha1, sha1, logmsg) < 0)) {
1501                unlock_ref(lock);
1502                return -1;
1503        }
1504        if (strcmp(lock->orig_ref_name, "HEAD") != 0) {
1505                /*
1506                 * Special hack: If a branch is updated directly and HEAD
1507                 * points to it (may happen on the remote side of a push
1508                 * for example) then logically the HEAD reflog should be
1509                 * updated too.
1510                 * A generic solution implies reverse symref information,
1511                 * but finding all symrefs pointing to the given branch
1512                 * would be rather costly for this rare event (the direct
1513                 * update of a branch) to be worth it.  So let's cheat and
1514                 * check with HEAD only which should cover 99% of all usage
1515                 * scenarios (even 100% of the default ones).
1516                 */
1517                unsigned char head_sha1[20];
1518                int head_flag;
1519                const char *head_ref;
1520                head_ref = resolve_ref("HEAD", head_sha1, 1, &head_flag);
1521                if (head_ref && (head_flag & REF_ISSYMREF) &&
1522                    !strcmp(head_ref, lock->ref_name))
1523                        log_ref_write("HEAD", lock->old_sha1, sha1, logmsg);
1524        }
1525        if (commit_ref(lock)) {
1526                error("Couldn't set %s", lock->ref_name);
1527                unlock_ref(lock);
1528                return -1;
1529        }
1530        unlock_ref(lock);
1531        return 0;
1532}
1533
1534int create_symref(const char *ref_target, const char *refs_heads_master,
1535                  const char *logmsg)
1536{
1537        const char *lockpath;
1538        char ref[1000];
1539        int fd, len, written;
1540        char *git_HEAD = git_pathdup("%s", ref_target);
1541        unsigned char old_sha1[20], new_sha1[20];
1542
1543        if (logmsg && read_ref(ref_target, old_sha1))
1544                hashclr(old_sha1);
1545
1546        if (safe_create_leading_directories(git_HEAD) < 0)
1547                return error("unable to create directory for %s", git_HEAD);
1548
1549#ifndef NO_SYMLINK_HEAD
1550        if (prefer_symlink_refs) {
1551                unlink(git_HEAD);
1552                if (!symlink(refs_heads_master, git_HEAD))
1553                        goto done;
1554                fprintf(stderr, "no symlink - falling back to symbolic ref\n");
1555        }
1556#endif
1557
1558        len = snprintf(ref, sizeof(ref), "ref: %s\n", refs_heads_master);
1559        if (sizeof(ref) <= len) {
1560                error("refname too long: %s", refs_heads_master);
1561                goto error_free_return;
1562        }
1563        lockpath = mkpath("%s.lock", git_HEAD);
1564        fd = open(lockpath, O_CREAT | O_EXCL | O_WRONLY, 0666);
1565        if (fd < 0) {
1566                error("Unable to open %s for writing", lockpath);
1567                goto error_free_return;
1568        }
1569        written = write_in_full(fd, ref, len);
1570        if (close(fd) != 0 || written != len) {
1571                error("Unable to write to %s", lockpath);
1572                goto error_unlink_return;
1573        }
1574        if (rename(lockpath, git_HEAD) < 0) {
1575                error("Unable to create %s", git_HEAD);
1576                goto error_unlink_return;
1577        }
1578        if (adjust_shared_perm(git_HEAD)) {
1579                error("Unable to fix permissions on %s", lockpath);
1580        error_unlink_return:
1581                unlink_or_warn(lockpath);
1582        error_free_return:
1583                free(git_HEAD);
1584                return -1;
1585        }
1586
1587#ifndef NO_SYMLINK_HEAD
1588        done:
1589#endif
1590        if (logmsg && !read_ref(refs_heads_master, new_sha1))
1591                log_ref_write(ref_target, old_sha1, new_sha1, logmsg);
1592
1593        free(git_HEAD);
1594        return 0;
1595}
1596
1597static char *ref_msg(const char *line, const char *endp)
1598{
1599        const char *ep;
1600        line += 82;
1601        ep = memchr(line, '\n', endp - line);
1602        if (!ep)
1603                ep = endp;
1604        return xmemdupz(line, ep - line);
1605}
1606
1607int 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)
1608{
1609        const char *logfile, *logdata, *logend, *rec, *lastgt, *lastrec;
1610        char *tz_c;
1611        int logfd, tz, reccnt = 0;
1612        struct stat st;
1613        unsigned long date;
1614        unsigned char logged_sha1[20];
1615        void *log_mapped;
1616        size_t mapsz;
1617
1618        logfile = git_path("logs/%s", ref);
1619        logfd = open(logfile, O_RDONLY, 0);
1620        if (logfd < 0)
1621                die_errno("Unable to read log '%s'", logfile);
1622        fstat(logfd, &st);
1623        if (!st.st_size)
1624                die("Log %s is empty.", logfile);
1625        mapsz = xsize_t(st.st_size);
1626        log_mapped = xmmap(NULL, mapsz, PROT_READ, MAP_PRIVATE, logfd, 0);
1627        logdata = log_mapped;
1628        close(logfd);
1629
1630        lastrec = NULL;
1631        rec = logend = logdata + st.st_size;
1632        while (logdata < rec) {
1633                reccnt++;
1634                if (logdata < rec && *(rec-1) == '\n')
1635                        rec--;
1636                lastgt = NULL;
1637                while (logdata < rec && *(rec-1) != '\n') {
1638                        rec--;
1639                        if (*rec == '>')
1640                                lastgt = rec;
1641                }
1642                if (!lastgt)
1643                        die("Log %s is corrupt.", logfile);
1644                date = strtoul(lastgt + 1, &tz_c, 10);
1645                if (date <= at_time || cnt == 0) {
1646                        tz = strtoul(tz_c, NULL, 10);
1647                        if (msg)
1648                                *msg = ref_msg(rec, logend);
1649                        if (cutoff_time)
1650                                *cutoff_time = date;
1651                        if (cutoff_tz)
1652                                *cutoff_tz = tz;
1653                        if (cutoff_cnt)
1654                                *cutoff_cnt = reccnt - 1;
1655                        if (lastrec) {
1656                                if (get_sha1_hex(lastrec, logged_sha1))
1657                                        die("Log %s is corrupt.", logfile);
1658                                if (get_sha1_hex(rec + 41, sha1))
1659                                        die("Log %s is corrupt.", logfile);
1660                                if (hashcmp(logged_sha1, sha1)) {
1661                                        warning("Log %s has gap after %s.",
1662                                                logfile, show_date(date, tz, DATE_RFC2822));
1663                                }
1664                        }
1665                        else if (date == at_time) {
1666                                if (get_sha1_hex(rec + 41, sha1))
1667                                        die("Log %s is corrupt.", logfile);
1668                        }
1669                        else {
1670                                if (get_sha1_hex(rec + 41, logged_sha1))
1671                                        die("Log %s is corrupt.", logfile);
1672                                if (hashcmp(logged_sha1, sha1)) {
1673                                        warning("Log %s unexpectedly ended on %s.",
1674                                                logfile, show_date(date, tz, DATE_RFC2822));
1675                                }
1676                        }
1677                        munmap(log_mapped, mapsz);
1678                        return 0;
1679                }
1680                lastrec = rec;
1681                if (cnt > 0)
1682                        cnt--;
1683        }
1684
1685        rec = logdata;
1686        while (rec < logend && *rec != '>' && *rec != '\n')
1687                rec++;
1688        if (rec == logend || *rec == '\n')
1689                die("Log %s is corrupt.", logfile);
1690        date = strtoul(rec + 1, &tz_c, 10);
1691        tz = strtoul(tz_c, NULL, 10);
1692        if (get_sha1_hex(logdata, sha1))
1693                die("Log %s is corrupt.", logfile);
1694        if (is_null_sha1(sha1)) {
1695                if (get_sha1_hex(logdata + 41, sha1))
1696                        die("Log %s is corrupt.", logfile);
1697        }
1698        if (msg)
1699                *msg = ref_msg(logdata, logend);
1700        munmap(log_mapped, mapsz);
1701
1702        if (cutoff_time)
1703                *cutoff_time = date;
1704        if (cutoff_tz)
1705                *cutoff_tz = tz;
1706        if (cutoff_cnt)
1707                *cutoff_cnt = reccnt;
1708        return 1;
1709}
1710
1711int for_each_recent_reflog_ent(const char *ref, each_reflog_ent_fn fn, long ofs, void *cb_data)
1712{
1713        const char *logfile;
1714        FILE *logfp;
1715        struct strbuf sb = STRBUF_INIT;
1716        int ret = 0;
1717
1718        logfile = git_path("logs/%s", ref);
1719        logfp = fopen(logfile, "r");
1720        if (!logfp)
1721                return -1;
1722
1723        if (ofs) {
1724                struct stat statbuf;
1725                if (fstat(fileno(logfp), &statbuf) ||
1726                    statbuf.st_size < ofs ||
1727                    fseek(logfp, -ofs, SEEK_END) ||
1728                    strbuf_getwholeline(&sb, logfp, '\n')) {
1729                        fclose(logfp);
1730                        strbuf_release(&sb);
1731                        return -1;
1732                }
1733        }
1734
1735        while (!strbuf_getwholeline(&sb, logfp, '\n')) {
1736                unsigned char osha1[20], nsha1[20];
1737                char *email_end, *message;
1738                unsigned long timestamp;
1739                int tz;
1740
1741                /* old SP new SP name <email> SP time TAB msg LF */
1742                if (sb.len < 83 || sb.buf[sb.len - 1] != '\n' ||
1743                    get_sha1_hex(sb.buf, osha1) || sb.buf[40] != ' ' ||
1744                    get_sha1_hex(sb.buf + 41, nsha1) || sb.buf[81] != ' ' ||
1745                    !(email_end = strchr(sb.buf + 82, '>')) ||
1746                    email_end[1] != ' ' ||
1747                    !(timestamp = strtoul(email_end + 2, &message, 10)) ||
1748                    !message || message[0] != ' ' ||
1749                    (message[1] != '+' && message[1] != '-') ||
1750                    !isdigit(message[2]) || !isdigit(message[3]) ||
1751                    !isdigit(message[4]) || !isdigit(message[5]))
1752                        continue; /* corrupt? */
1753                email_end[1] = '\0';
1754                tz = strtol(message + 1, NULL, 10);
1755                if (message[6] != '\t')
1756                        message += 6;
1757                else
1758                        message += 7;
1759                ret = fn(osha1, nsha1, sb.buf + 82, timestamp, tz, message,
1760                         cb_data);
1761                if (ret)
1762                        break;
1763        }
1764        fclose(logfp);
1765        strbuf_release(&sb);
1766        return ret;
1767}
1768
1769int for_each_reflog_ent(const char *ref, each_reflog_ent_fn fn, void *cb_data)
1770{
1771        return for_each_recent_reflog_ent(ref, fn, 0, cb_data);
1772}
1773
1774static int do_for_each_reflog(const char *base, each_ref_fn fn, void *cb_data)
1775{
1776        DIR *dir = opendir(git_path("logs/%s", base));
1777        int retval = 0;
1778
1779        if (dir) {
1780                struct dirent *de;
1781                int baselen = strlen(base);
1782                char *log = xmalloc(baselen + 257);
1783
1784                memcpy(log, base, baselen);
1785                if (baselen && base[baselen-1] != '/')
1786                        log[baselen++] = '/';
1787
1788                while ((de = readdir(dir)) != NULL) {
1789                        struct stat st;
1790                        int namelen;
1791
1792                        if (de->d_name[0] == '.')
1793                                continue;
1794                        namelen = strlen(de->d_name);
1795                        if (namelen > 255)
1796                                continue;
1797                        if (has_extension(de->d_name, ".lock"))
1798                                continue;
1799                        memcpy(log + baselen, de->d_name, namelen+1);
1800                        if (stat(git_path("logs/%s", log), &st) < 0)
1801                                continue;
1802                        if (S_ISDIR(st.st_mode)) {
1803                                retval = do_for_each_reflog(log, fn, cb_data);
1804                        } else {
1805                                unsigned char sha1[20];
1806                                if (!resolve_ref(log, sha1, 0, NULL))
1807                                        retval = error("bad ref for %s", log);
1808                                else
1809                                        retval = fn(log, sha1, 0, cb_data);
1810                        }
1811                        if (retval)
1812                                break;
1813                }
1814                free(log);
1815                closedir(dir);
1816        }
1817        else if (*base)
1818                return errno;
1819        return retval;
1820}
1821
1822int for_each_reflog(each_ref_fn fn, void *cb_data)
1823{
1824        return do_for_each_reflog("", fn, cb_data);
1825}
1826
1827int update_ref(const char *action, const char *refname,
1828                const unsigned char *sha1, const unsigned char *oldval,
1829                int flags, enum action_on_err onerr)
1830{
1831        static struct ref_lock *lock;
1832        lock = lock_any_ref_for_update(refname, oldval, flags);
1833        if (!lock) {
1834                const char *str = "Cannot lock the ref '%s'.";
1835                switch (onerr) {
1836                case MSG_ON_ERR: error(str, refname); break;
1837                case DIE_ON_ERR: die(str, refname); break;
1838                case QUIET_ON_ERR: break;
1839                }
1840                return 1;
1841        }
1842        if (write_ref_sha1(lock, sha1, action) < 0) {
1843                const char *str = "Cannot update the ref '%s'.";
1844                switch (onerr) {
1845                case MSG_ON_ERR: error(str, refname); break;
1846                case DIE_ON_ERR: die(str, refname); break;
1847                case QUIET_ON_ERR: break;
1848                }
1849                return 1;
1850        }
1851        return 0;
1852}
1853
1854int ref_exists(char *refname)
1855{
1856        unsigned char sha1[20];
1857        return !!resolve_ref(refname, sha1, 1, NULL);
1858}
1859
1860struct ref *find_ref_by_name(const struct ref *list, const char *name)
1861{
1862        for ( ; list; list = list->next)
1863                if (!strcmp(list->name, name))
1864                        return (struct ref *)list;
1865        return NULL;
1866}
1867
1868/*
1869 * generate a format suitable for scanf from a ref_rev_parse_rules
1870 * rule, that is replace the "%.*s" spec with a "%s" spec
1871 */
1872static void gen_scanf_fmt(char *scanf_fmt, const char *rule)
1873{
1874        char *spec;
1875
1876        spec = strstr(rule, "%.*s");
1877        if (!spec || strstr(spec + 4, "%.*s"))
1878                die("invalid rule in ref_rev_parse_rules: %s", rule);
1879
1880        /* copy all until spec */
1881        strncpy(scanf_fmt, rule, spec - rule);
1882        scanf_fmt[spec - rule] = '\0';
1883        /* copy new spec */
1884        strcat(scanf_fmt, "%s");
1885        /* copy remaining rule */
1886        strcat(scanf_fmt, spec + 4);
1887
1888        return;
1889}
1890
1891char *shorten_unambiguous_ref(const char *ref, int strict)
1892{
1893        int i;
1894        static char **scanf_fmts;
1895        static int nr_rules;
1896        char *short_name;
1897
1898        /* pre generate scanf formats from ref_rev_parse_rules[] */
1899        if (!nr_rules) {
1900                size_t total_len = 0;
1901
1902                /* the rule list is NULL terminated, count them first */
1903                for (; ref_rev_parse_rules[nr_rules]; nr_rules++)
1904                        /* no +1 because strlen("%s") < strlen("%.*s") */
1905                        total_len += strlen(ref_rev_parse_rules[nr_rules]);
1906
1907                scanf_fmts = xmalloc(nr_rules * sizeof(char *) + total_len);
1908
1909                total_len = 0;
1910                for (i = 0; i < nr_rules; i++) {
1911                        scanf_fmts[i] = (char *)&scanf_fmts[nr_rules]
1912                                        + total_len;
1913                        gen_scanf_fmt(scanf_fmts[i], ref_rev_parse_rules[i]);
1914                        total_len += strlen(ref_rev_parse_rules[i]);
1915                }
1916        }
1917
1918        /* bail out if there are no rules */
1919        if (!nr_rules)
1920                return xstrdup(ref);
1921
1922        /* buffer for scanf result, at most ref must fit */
1923        short_name = xstrdup(ref);
1924
1925        /* skip first rule, it will always match */
1926        for (i = nr_rules - 1; i > 0 ; --i) {
1927                int j;
1928                int rules_to_fail = i;
1929                int short_name_len;
1930
1931                if (1 != sscanf(ref, scanf_fmts[i], short_name))
1932                        continue;
1933
1934                short_name_len = strlen(short_name);
1935
1936                /*
1937                 * in strict mode, all (except the matched one) rules
1938                 * must fail to resolve to a valid non-ambiguous ref
1939                 */
1940                if (strict)
1941                        rules_to_fail = nr_rules;
1942
1943                /*
1944                 * check if the short name resolves to a valid ref,
1945                 * but use only rules prior to the matched one
1946                 */
1947                for (j = 0; j < rules_to_fail; j++) {
1948                        const char *rule = ref_rev_parse_rules[j];
1949                        unsigned char short_objectname[20];
1950                        char refname[PATH_MAX];
1951
1952                        /* skip matched rule */
1953                        if (i == j)
1954                                continue;
1955
1956                        /*
1957                         * the short name is ambiguous, if it resolves
1958                         * (with this previous rule) to a valid ref
1959                         * read_ref() returns 0 on success
1960                         */
1961                        mksnpath(refname, sizeof(refname),
1962                                 rule, short_name_len, short_name);
1963                        if (!read_ref(refname, short_objectname))
1964                                break;
1965                }
1966
1967                /*
1968                 * short name is non-ambiguous if all previous rules
1969                 * haven't resolved to a valid ref
1970                 */
1971                if (j == rules_to_fail)
1972                        return short_name;
1973        }
1974
1975        free(short_name);
1976        return xstrdup(ref);
1977}