refs.con commit Merge branch 'ef/msvc-noreturn' (c2c8656)
   1#include "cache.h"
   2#include "refs.h"
   3#include "object.h"
   4#include "tag.h"
   5#include "dir.h"
   6
   7/* ISSYMREF=01 and ISPACKED=02 are public interfaces */
   8#define REF_KNOWS_PEELED 04
   9
  10struct ref_list {
  11        struct ref_list *next;
  12        unsigned char flag; /* ISSYMREF? ISPACKED? */
  13        unsigned char sha1[20];
  14        unsigned char peeled[20];
  15        char name[FLEX_ARRAY];
  16};
  17
  18static const char *parse_ref_line(char *line, unsigned char *sha1)
  19{
  20        /*
  21         * 42: the answer to everything.
  22         *
  23         * In this case, it happens to be the answer to
  24         *  40 (length of sha1 hex representation)
  25         *  +1 (space in between hex and name)
  26         *  +1 (newline at the end of the line)
  27         */
  28        int len = strlen(line) - 42;
  29
  30        if (len <= 0)
  31                return NULL;
  32        if (get_sha1_hex(line, sha1) < 0)
  33                return NULL;
  34        if (!isspace(line[40]))
  35                return NULL;
  36        line += 41;
  37        if (isspace(*line))
  38                return NULL;
  39        if (line[len] != '\n')
  40                return NULL;
  41        line[len] = 0;
  42
  43        return line;
  44}
  45
  46static struct ref_list *add_ref(const char *name, const unsigned char *sha1,
  47                                int flag, struct ref_list *list,
  48                                struct ref_list **new_entry)
  49{
  50        int len;
  51        struct ref_list *entry;
  52
  53        /* Allocate it and add it in.. */
  54        len = strlen(name) + 1;
  55        entry = xmalloc(sizeof(struct ref_list) + len);
  56        hashcpy(entry->sha1, sha1);
  57        hashclr(entry->peeled);
  58        memcpy(entry->name, name, len);
  59        entry->flag = flag;
  60        entry->next = list;
  61        if (new_entry)
  62                *new_entry = entry;
  63        return entry;
  64}
  65
  66/* merge sort the ref list */
  67static struct ref_list *sort_ref_list(struct ref_list *list)
  68{
  69        int psize, qsize, last_merge_count, cmp;
  70        struct ref_list *p, *q, *l, *e;
  71        struct ref_list *new_list = list;
  72        int k = 1;
  73        int merge_count = 0;
  74
  75        if (!list)
  76                return list;
  77
  78        do {
  79                last_merge_count = merge_count;
  80                merge_count = 0;
  81
  82                psize = 0;
  83
  84                p = new_list;
  85                q = new_list;
  86                new_list = NULL;
  87                l = NULL;
  88
  89                while (p) {
  90                        merge_count++;
  91
  92                        while (psize < k && q->next) {
  93                                q = q->next;
  94                                psize++;
  95                        }
  96                        qsize = k;
  97
  98                        while ((psize > 0) || (qsize > 0 && q)) {
  99                                if (qsize == 0 || !q) {
 100                                        e = p;
 101                                        p = p->next;
 102                                        psize--;
 103                                } else if (psize == 0) {
 104                                        e = q;
 105                                        q = q->next;
 106                                        qsize--;
 107                                } else {
 108                                        cmp = strcmp(q->name, p->name);
 109                                        if (cmp < 0) {
 110                                                e = q;
 111                                                q = q->next;
 112                                                qsize--;
 113                                        } else if (cmp > 0) {
 114                                                e = p;
 115                                                p = p->next;
 116                                                psize--;
 117                                        } else {
 118                                                if (hashcmp(q->sha1, p->sha1))
 119                                                        die("Duplicated ref, and SHA1s don't match: %s",
 120                                                            q->name);
 121                                                warning("Duplicated ref: %s", q->name);
 122                                                e = q;
 123                                                q = q->next;
 124                                                qsize--;
 125                                                free(e);
 126                                                e = p;
 127                                                p = p->next;
 128                                                psize--;
 129                                        }
 130                                }
 131
 132                                e->next = NULL;
 133
 134                                if (l)
 135                                        l->next = e;
 136                                if (!new_list)
 137                                        new_list = e;
 138                                l = e;
 139                        }
 140
 141                        p = q;
 142                };
 143
 144                k = k * 2;
 145        } while ((last_merge_count != merge_count) || (last_merge_count != 1));
 146
 147        return new_list;
 148}
 149
 150/*
 151 * Future: need to be in "struct repository"
 152 * when doing a full libification.
 153 */
 154static struct cached_refs {
 155        char did_loose;
 156        char did_packed;
 157        struct ref_list *loose;
 158        struct ref_list *packed;
 159} cached_refs;
 160static struct ref_list *current_ref;
 161
 162static struct ref_list *extra_refs;
 163
 164static void free_ref_list(struct ref_list *list)
 165{
 166        struct ref_list *next;
 167        for ( ; list; list = next) {
 168                next = list->next;
 169                free(list);
 170        }
 171}
 172
 173static void invalidate_cached_refs(void)
 174{
 175        struct cached_refs *ca = &cached_refs;
 176
 177        if (ca->did_loose && ca->loose)
 178                free_ref_list(ca->loose);
 179        if (ca->did_packed && ca->packed)
 180                free_ref_list(ca->packed);
 181        ca->loose = ca->packed = NULL;
 182        ca->did_loose = ca->did_packed = 0;
 183}
 184
 185static void read_packed_refs(FILE *f, struct cached_refs *cached_refs)
 186{
 187        struct ref_list *list = NULL;
 188        struct ref_list *last = NULL;
 189        char refline[PATH_MAX];
 190        int flag = REF_ISPACKED;
 191
 192        while (fgets(refline, sizeof(refline), f)) {
 193                unsigned char sha1[20];
 194                const char *name;
 195                static const char header[] = "# pack-refs with:";
 196
 197                if (!strncmp(refline, header, sizeof(header)-1)) {
 198                        const char *traits = refline + sizeof(header) - 1;
 199                        if (strstr(traits, " peeled "))
 200                                flag |= REF_KNOWS_PEELED;
 201                        /* perhaps other traits later as well */
 202                        continue;
 203                }
 204
 205                name = parse_ref_line(refline, sha1);
 206                if (name) {
 207                        list = add_ref(name, sha1, flag, list, &last);
 208                        continue;
 209                }
 210                if (last &&
 211                    refline[0] == '^' &&
 212                    strlen(refline) == 42 &&
 213                    refline[41] == '\n' &&
 214                    !get_sha1_hex(refline + 1, sha1))
 215                        hashcpy(last->peeled, sha1);
 216        }
 217        cached_refs->packed = sort_ref_list(list);
 218}
 219
 220void add_extra_ref(const char *name, const unsigned char *sha1, int flag)
 221{
 222        extra_refs = add_ref(name, sha1, flag, extra_refs, NULL);
 223}
 224
 225void clear_extra_refs(void)
 226{
 227        free_ref_list(extra_refs);
 228        extra_refs = NULL;
 229}
 230
 231static struct ref_list *get_packed_refs(void)
 232{
 233        if (!cached_refs.did_packed) {
 234                FILE *f = fopen(git_path("packed-refs"), "r");
 235                cached_refs.packed = NULL;
 236                if (f) {
 237                        read_packed_refs(f, &cached_refs);
 238                        fclose(f);
 239                }
 240                cached_refs.did_packed = 1;
 241        }
 242        return cached_refs.packed;
 243}
 244
 245static struct ref_list *get_ref_dir(const char *base, struct ref_list *list)
 246{
 247        DIR *dir = opendir(git_path("%s", base));
 248
 249        if (dir) {
 250                struct dirent *de;
 251                int baselen = strlen(base);
 252                char *ref = xmalloc(baselen + 257);
 253
 254                memcpy(ref, base, baselen);
 255                if (baselen && base[baselen-1] != '/')
 256                        ref[baselen++] = '/';
 257
 258                while ((de = readdir(dir)) != NULL) {
 259                        unsigned char sha1[20];
 260                        struct stat st;
 261                        int flag;
 262                        int namelen;
 263
 264                        if (de->d_name[0] == '.')
 265                                continue;
 266                        namelen = strlen(de->d_name);
 267                        if (namelen > 255)
 268                                continue;
 269                        if (has_extension(de->d_name, ".lock"))
 270                                continue;
 271                        memcpy(ref + baselen, de->d_name, namelen+1);
 272                        if (stat(git_path("%s", ref), &st) < 0)
 273                                continue;
 274                        if (S_ISDIR(st.st_mode)) {
 275                                list = get_ref_dir(ref, list);
 276                                continue;
 277                        }
 278                        if (!resolve_ref(ref, sha1, 1, &flag))
 279                                hashclr(sha1);
 280                        list = add_ref(ref, sha1, flag, list, NULL);
 281                }
 282                free(ref);
 283                closedir(dir);
 284        }
 285        return sort_ref_list(list);
 286}
 287
 288struct warn_if_dangling_data {
 289        const char *refname;
 290        const char *msg_fmt;
 291};
 292
 293static int warn_if_dangling_symref(const char *refname, const unsigned char *sha1,
 294                                   int flags, void *cb_data)
 295{
 296        struct warn_if_dangling_data *d = cb_data;
 297        const char *resolves_to;
 298        unsigned char junk[20];
 299
 300        if (!(flags & REF_ISSYMREF))
 301                return 0;
 302
 303        resolves_to = resolve_ref(refname, junk, 0, NULL);
 304        if (!resolves_to || strcmp(resolves_to, d->refname))
 305                return 0;
 306
 307        printf(d->msg_fmt, refname);
 308        return 0;
 309}
 310
 311void warn_dangling_symref(const char *msg_fmt, const char *refname)
 312{
 313        struct warn_if_dangling_data data = { refname, msg_fmt };
 314        for_each_rawref(warn_if_dangling_symref, &data);
 315}
 316
 317static struct ref_list *get_loose_refs(void)
 318{
 319        if (!cached_refs.did_loose) {
 320                cached_refs.loose = get_ref_dir("refs", NULL);
 321                cached_refs.did_loose = 1;
 322        }
 323        return cached_refs.loose;
 324}
 325
 326/* We allow "recursive" symbolic refs. Only within reason, though */
 327#define MAXDEPTH 5
 328#define MAXREFLEN (1024)
 329
 330static int resolve_gitlink_packed_ref(char *name, int pathlen, const char *refname, unsigned char *result)
 331{
 332        FILE *f;
 333        struct cached_refs refs;
 334        struct ref_list *ref;
 335        int retval;
 336
 337        strcpy(name + pathlen, "packed-refs");
 338        f = fopen(name, "r");
 339        if (!f)
 340                return -1;
 341        read_packed_refs(f, &refs);
 342        fclose(f);
 343        ref = refs.packed;
 344        retval = -1;
 345        while (ref) {
 346                if (!strcmp(ref->name, refname)) {
 347                        retval = 0;
 348                        memcpy(result, ref->sha1, 20);
 349                        break;
 350                }
 351                ref = ref->next;
 352        }
 353        free_ref_list(refs.packed);
 354        return retval;
 355}
 356
 357static int resolve_gitlink_ref_recursive(char *name, int pathlen, const char *refname, unsigned char *result, int recursion)
 358{
 359        int fd, len = strlen(refname);
 360        char buffer[128], *p;
 361
 362        if (recursion > MAXDEPTH || len > MAXREFLEN)
 363                return -1;
 364        memcpy(name + pathlen, refname, len+1);
 365        fd = open(name, O_RDONLY);
 366        if (fd < 0)
 367                return resolve_gitlink_packed_ref(name, pathlen, refname, result);
 368
 369        len = read(fd, buffer, sizeof(buffer)-1);
 370        close(fd);
 371        if (len < 0)
 372                return -1;
 373        while (len && isspace(buffer[len-1]))
 374                len--;
 375        buffer[len] = 0;
 376
 377        /* Was it a detached head or an old-fashioned symlink? */
 378        if (!get_sha1_hex(buffer, result))
 379                return 0;
 380
 381        /* Symref? */
 382        if (strncmp(buffer, "ref:", 4))
 383                return -1;
 384        p = buffer + 4;
 385        while (isspace(*p))
 386                p++;
 387
 388        return resolve_gitlink_ref_recursive(name, pathlen, p, result, recursion+1);
 389}
 390
 391int resolve_gitlink_ref(const char *path, const char *refname, unsigned char *result)
 392{
 393        int len = strlen(path), retval;
 394        char *gitdir;
 395        const char *tmp;
 396
 397        while (len && path[len-1] == '/')
 398                len--;
 399        if (!len)
 400                return -1;
 401        gitdir = xmalloc(len + MAXREFLEN + 8);
 402        memcpy(gitdir, path, len);
 403        memcpy(gitdir + len, "/.git", 6);
 404        len += 5;
 405
 406        tmp = read_gitfile_gently(gitdir);
 407        if (tmp) {
 408                free(gitdir);
 409                len = strlen(tmp);
 410                gitdir = xmalloc(len + MAXREFLEN + 3);
 411                memcpy(gitdir, tmp, len);
 412        }
 413        gitdir[len] = '/';
 414        gitdir[++len] = '\0';
 415        retval = resolve_gitlink_ref_recursive(gitdir, len, refname, result, 0);
 416        free(gitdir);
 417        return retval;
 418}
 419
 420/*
 421 * If the "reading" argument is set, this function finds out what _object_
 422 * the ref points at by "reading" the ref.  The ref, if it is not symbolic,
 423 * has to exist, and if it is symbolic, it has to point at an existing ref,
 424 * because the "read" goes through the symref to the ref it points at.
 425 *
 426 * The access that is not "reading" may often be "writing", but does not
 427 * have to; it can be merely checking _where it leads to_. If it is a
 428 * prelude to "writing" to the ref, a write to a symref that points at
 429 * yet-to-be-born ref will create the real ref pointed by the symref.
 430 * reading=0 allows the caller to check where such a symref leads to.
 431 */
 432const char *resolve_ref(const char *ref, unsigned char *sha1, int reading, int *flag)
 433{
 434        int depth = MAXDEPTH;
 435        ssize_t len;
 436        char buffer[256];
 437        static char ref_buffer[256];
 438
 439        if (flag)
 440                *flag = 0;
 441
 442        for (;;) {
 443                char path[PATH_MAX];
 444                struct stat st;
 445                char *buf;
 446                int fd;
 447
 448                if (--depth < 0)
 449                        return NULL;
 450
 451                git_snpath(path, sizeof(path), "%s", ref);
 452                /* Special case: non-existing file. */
 453                if (lstat(path, &st) < 0) {
 454                        struct ref_list *list = get_packed_refs();
 455                        while (list) {
 456                                if (!strcmp(ref, list->name)) {
 457                                        hashcpy(sha1, list->sha1);
 458                                        if (flag)
 459                                                *flag |= REF_ISPACKED;
 460                                        return ref;
 461                                }
 462                                list = list->next;
 463                        }
 464                        if (reading || errno != ENOENT)
 465                                return NULL;
 466                        hashclr(sha1);
 467                        return ref;
 468                }
 469
 470                /* Follow "normalized" - ie "refs/.." symlinks by hand */
 471                if (S_ISLNK(st.st_mode)) {
 472                        len = readlink(path, buffer, sizeof(buffer)-1);
 473                        if (len >= 5 && !memcmp("refs/", buffer, 5)) {
 474                                buffer[len] = 0;
 475                                strcpy(ref_buffer, buffer);
 476                                ref = ref_buffer;
 477                                if (flag)
 478                                        *flag |= REF_ISSYMREF;
 479                                continue;
 480                        }
 481                }
 482
 483                /* Is it a directory? */
 484                if (S_ISDIR(st.st_mode)) {
 485                        errno = EISDIR;
 486                        return NULL;
 487                }
 488
 489                /*
 490                 * Anything else, just open it and try to use it as
 491                 * a ref
 492                 */
 493                fd = open(path, O_RDONLY);
 494                if (fd < 0)
 495                        return NULL;
 496                len = read_in_full(fd, buffer, sizeof(buffer)-1);
 497                close(fd);
 498
 499                /*
 500                 * Is it a symbolic ref?
 501                 */
 502                if (len < 4 || memcmp("ref:", buffer, 4))
 503                        break;
 504                buf = buffer + 4;
 505                len -= 4;
 506                while (len && isspace(*buf))
 507                        buf++, len--;
 508                while (len && isspace(buf[len-1]))
 509                        len--;
 510                buf[len] = 0;
 511                memcpy(ref_buffer, buf, len + 1);
 512                ref = ref_buffer;
 513                if (flag)
 514                        *flag |= REF_ISSYMREF;
 515        }
 516        if (len < 40 || get_sha1_hex(buffer, sha1))
 517                return NULL;
 518        return ref;
 519}
 520
 521int read_ref(const char *ref, unsigned char *sha1)
 522{
 523        if (resolve_ref(ref, sha1, 1, NULL))
 524                return 0;
 525        return -1;
 526}
 527
 528#define DO_FOR_EACH_INCLUDE_BROKEN 01
 529static int do_one_ref(const char *base, each_ref_fn fn, int trim,
 530                      int flags, void *cb_data, struct ref_list *entry)
 531{
 532        if (strncmp(base, entry->name, trim))
 533                return 0;
 534        /* Is this a "negative ref" that represents a deleted ref? */
 535        if (is_null_sha1(entry->sha1))
 536                return 0;
 537        if (!(flags & DO_FOR_EACH_INCLUDE_BROKEN)) {
 538                if (!has_sha1_file(entry->sha1)) {
 539                        error("%s does not point to a valid object!", entry->name);
 540                        return 0;
 541                }
 542        }
 543        current_ref = entry;
 544        return fn(entry->name + trim, entry->sha1, entry->flag, cb_data);
 545}
 546
 547int peel_ref(const char *ref, unsigned char *sha1)
 548{
 549        int flag;
 550        unsigned char base[20];
 551        struct object *o;
 552
 553        if (current_ref && (current_ref->name == ref
 554                || !strcmp(current_ref->name, ref))) {
 555                if (current_ref->flag & REF_KNOWS_PEELED) {
 556                        hashcpy(sha1, current_ref->peeled);
 557                        return 0;
 558                }
 559                hashcpy(base, current_ref->sha1);
 560                goto fallback;
 561        }
 562
 563        if (!resolve_ref(ref, base, 1, &flag))
 564                return -1;
 565
 566        if ((flag & REF_ISPACKED)) {
 567                struct ref_list *list = get_packed_refs();
 568
 569                while (list) {
 570                        if (!strcmp(list->name, ref)) {
 571                                if (list->flag & REF_KNOWS_PEELED) {
 572                                        hashcpy(sha1, list->peeled);
 573                                        return 0;
 574                                }
 575                                /* older pack-refs did not leave peeled ones */
 576                                break;
 577                        }
 578                        list = list->next;
 579                }
 580        }
 581
 582fallback:
 583        o = parse_object(base);
 584        if (o && o->type == OBJ_TAG) {
 585                o = deref_tag(o, ref, 0);
 586                if (o) {
 587                        hashcpy(sha1, o->sha1);
 588                        return 0;
 589                }
 590        }
 591        return -1;
 592}
 593
 594static int do_for_each_ref(const char *base, each_ref_fn fn, int trim,
 595                           int flags, void *cb_data)
 596{
 597        int retval = 0;
 598        struct ref_list *packed = get_packed_refs();
 599        struct ref_list *loose = get_loose_refs();
 600
 601        struct ref_list *extra;
 602
 603        for (extra = extra_refs; extra; extra = extra->next)
 604                retval = do_one_ref(base, fn, trim, flags, cb_data, extra);
 605
 606        while (packed && loose) {
 607                struct ref_list *entry;
 608                int cmp = strcmp(packed->name, loose->name);
 609                if (!cmp) {
 610                        packed = packed->next;
 611                        continue;
 612                }
 613                if (cmp > 0) {
 614                        entry = loose;
 615                        loose = loose->next;
 616                } else {
 617                        entry = packed;
 618                        packed = packed->next;
 619                }
 620                retval = do_one_ref(base, fn, trim, flags, cb_data, entry);
 621                if (retval)
 622                        goto end_each;
 623        }
 624
 625        for (packed = packed ? packed : loose; packed; packed = packed->next) {
 626                retval = do_one_ref(base, fn, trim, flags, cb_data, packed);
 627                if (retval)
 628                        goto end_each;
 629        }
 630
 631end_each:
 632        current_ref = NULL;
 633        return retval;
 634}
 635
 636int head_ref(each_ref_fn fn, void *cb_data)
 637{
 638        unsigned char sha1[20];
 639        int flag;
 640
 641        if (resolve_ref("HEAD", sha1, 1, &flag))
 642                return fn("HEAD", sha1, flag, cb_data);
 643        return 0;
 644}
 645
 646int for_each_ref(each_ref_fn fn, void *cb_data)
 647{
 648        return do_for_each_ref("refs/", fn, 0, 0, cb_data);
 649}
 650
 651int for_each_ref_in(const char *prefix, each_ref_fn fn, void *cb_data)
 652{
 653        return do_for_each_ref(prefix, fn, strlen(prefix), 0, cb_data);
 654}
 655
 656int for_each_tag_ref(each_ref_fn fn, void *cb_data)
 657{
 658        return for_each_ref_in("refs/tags/", fn, cb_data);
 659}
 660
 661int for_each_branch_ref(each_ref_fn fn, void *cb_data)
 662{
 663        return for_each_ref_in("refs/heads/", fn, cb_data);
 664}
 665
 666int for_each_remote_ref(each_ref_fn fn, void *cb_data)
 667{
 668        return for_each_ref_in("refs/remotes/", fn, cb_data);
 669}
 670
 671int for_each_replace_ref(each_ref_fn fn, void *cb_data)
 672{
 673        return do_for_each_ref("refs/replace/", fn, 13, 0, cb_data);
 674}
 675
 676int for_each_rawref(each_ref_fn fn, void *cb_data)
 677{
 678        return do_for_each_ref("refs/", fn, 0,
 679                               DO_FOR_EACH_INCLUDE_BROKEN, cb_data);
 680}
 681
 682/*
 683 * Make sure "ref" is something reasonable to have under ".git/refs/";
 684 * We do not like it if:
 685 *
 686 * - any path component of it begins with ".", or
 687 * - it has double dots "..", or
 688 * - it has ASCII control character, "~", "^", ":" or SP, anywhere, or
 689 * - it ends with a "/".
 690 * - it ends with ".lock"
 691 * - it contains a "\" (backslash)
 692 */
 693
 694static inline int bad_ref_char(int ch)
 695{
 696        if (((unsigned) ch) <= ' ' ||
 697            ch == '~' || ch == '^' || ch == ':' || ch == '\\')
 698                return 1;
 699        /* 2.13 Pattern Matching Notation */
 700        if (ch == '?' || ch == '[') /* Unsupported */
 701                return 1;
 702        if (ch == '*') /* Supported at the end */
 703                return 2;
 704        return 0;
 705}
 706
 707int check_ref_format(const char *ref)
 708{
 709        int ch, level, bad_type, last;
 710        int ret = CHECK_REF_FORMAT_OK;
 711        const char *cp = ref;
 712
 713        level = 0;
 714        while (1) {
 715                while ((ch = *cp++) == '/')
 716                        ; /* tolerate duplicated slashes */
 717                if (!ch)
 718                        /* should not end with slashes */
 719                        return CHECK_REF_FORMAT_ERROR;
 720
 721                /* we are at the beginning of the path component */
 722                if (ch == '.')
 723                        return CHECK_REF_FORMAT_ERROR;
 724                bad_type = bad_ref_char(ch);
 725                if (bad_type) {
 726                        if (bad_type == 2 && (!*cp || *cp == '/') &&
 727                            ret == CHECK_REF_FORMAT_OK)
 728                                ret = CHECK_REF_FORMAT_WILDCARD;
 729                        else
 730                                return CHECK_REF_FORMAT_ERROR;
 731                }
 732
 733                last = ch;
 734                /* scan the rest of the path component */
 735                while ((ch = *cp++) != 0) {
 736                        bad_type = bad_ref_char(ch);
 737                        if (bad_type)
 738                                return CHECK_REF_FORMAT_ERROR;
 739                        if (ch == '/')
 740                                break;
 741                        if (last == '.' && ch == '.')
 742                                return CHECK_REF_FORMAT_ERROR;
 743                        if (last == '@' && ch == '{')
 744                                return CHECK_REF_FORMAT_ERROR;
 745                        last = ch;
 746                }
 747                level++;
 748                if (!ch) {
 749                        if (ref <= cp - 2 && cp[-2] == '.')
 750                                return CHECK_REF_FORMAT_ERROR;
 751                        if (level < 2)
 752                                return CHECK_REF_FORMAT_ONELEVEL;
 753                        if (has_extension(ref, ".lock"))
 754                                return CHECK_REF_FORMAT_ERROR;
 755                        return ret;
 756                }
 757        }
 758}
 759
 760const char *prettify_refname(const char *name)
 761{
 762        return name + (
 763                !prefixcmp(name, "refs/heads/") ? 11 :
 764                !prefixcmp(name, "refs/tags/") ? 10 :
 765                !prefixcmp(name, "refs/remotes/") ? 13 :
 766                0);
 767}
 768
 769const char *ref_rev_parse_rules[] = {
 770        "%.*s",
 771        "refs/%.*s",
 772        "refs/tags/%.*s",
 773        "refs/heads/%.*s",
 774        "refs/remotes/%.*s",
 775        "refs/remotes/%.*s/HEAD",
 776        NULL
 777};
 778
 779const char *ref_fetch_rules[] = {
 780        "%.*s",
 781        "refs/%.*s",
 782        "refs/heads/%.*s",
 783        NULL
 784};
 785
 786int refname_match(const char *abbrev_name, const char *full_name, const char **rules)
 787{
 788        const char **p;
 789        const int abbrev_name_len = strlen(abbrev_name);
 790
 791        for (p = rules; *p; p++) {
 792                if (!strcmp(full_name, mkpath(*p, abbrev_name_len, abbrev_name))) {
 793                        return 1;
 794                }
 795        }
 796
 797        return 0;
 798}
 799
 800static struct ref_lock *verify_lock(struct ref_lock *lock,
 801        const unsigned char *old_sha1, int mustexist)
 802{
 803        if (!resolve_ref(lock->ref_name, lock->old_sha1, mustexist, NULL)) {
 804                error("Can't verify ref %s", lock->ref_name);
 805                unlock_ref(lock);
 806                return NULL;
 807        }
 808        if (hashcmp(lock->old_sha1, old_sha1)) {
 809                error("Ref %s is at %s but expected %s", lock->ref_name,
 810                        sha1_to_hex(lock->old_sha1), sha1_to_hex(old_sha1));
 811                unlock_ref(lock);
 812                return NULL;
 813        }
 814        return lock;
 815}
 816
 817static int remove_empty_directories(const char *file)
 818{
 819        /* we want to create a file but there is a directory there;
 820         * if that is an empty directory (or a directory that contains
 821         * only empty directories), remove them.
 822         */
 823        struct strbuf path;
 824        int result;
 825
 826        strbuf_init(&path, 20);
 827        strbuf_addstr(&path, file);
 828
 829        result = remove_dir_recursively(&path, REMOVE_DIR_EMPTY_ONLY);
 830
 831        strbuf_release(&path);
 832
 833        return result;
 834}
 835
 836static int is_refname_available(const char *ref, const char *oldref,
 837                                struct ref_list *list, int quiet)
 838{
 839        int namlen = strlen(ref); /* e.g. 'foo/bar' */
 840        while (list) {
 841                /* list->name could be 'foo' or 'foo/bar/baz' */
 842                if (!oldref || strcmp(oldref, list->name)) {
 843                        int len = strlen(list->name);
 844                        int cmplen = (namlen < len) ? namlen : len;
 845                        const char *lead = (namlen < len) ? list->name : ref;
 846                        if (!strncmp(ref, list->name, cmplen) &&
 847                            lead[cmplen] == '/') {
 848                                if (!quiet)
 849                                        error("'%s' exists; cannot create '%s'",
 850                                              list->name, ref);
 851                                return 0;
 852                        }
 853                }
 854                list = list->next;
 855        }
 856        return 1;
 857}
 858
 859static struct ref_lock *lock_ref_sha1_basic(const char *ref, const unsigned char *old_sha1, int flags, int *type_p)
 860{
 861        char *ref_file;
 862        const char *orig_ref = ref;
 863        struct ref_lock *lock;
 864        int last_errno = 0;
 865        int type, lflags;
 866        int mustexist = (old_sha1 && !is_null_sha1(old_sha1));
 867        int missing = 0;
 868
 869        lock = xcalloc(1, sizeof(struct ref_lock));
 870        lock->lock_fd = -1;
 871
 872        ref = resolve_ref(ref, lock->old_sha1, mustexist, &type);
 873        if (!ref && errno == EISDIR) {
 874                /* we are trying to lock foo but we used to
 875                 * have foo/bar which now does not exist;
 876                 * it is normal for the empty directory 'foo'
 877                 * to remain.
 878                 */
 879                ref_file = git_path("%s", orig_ref);
 880                if (remove_empty_directories(ref_file)) {
 881                        last_errno = errno;
 882                        error("there are still refs under '%s'", orig_ref);
 883                        goto error_return;
 884                }
 885                ref = resolve_ref(orig_ref, lock->old_sha1, mustexist, &type);
 886        }
 887        if (type_p)
 888            *type_p = type;
 889        if (!ref) {
 890                last_errno = errno;
 891                error("unable to resolve reference %s: %s",
 892                        orig_ref, strerror(errno));
 893                goto error_return;
 894        }
 895        missing = is_null_sha1(lock->old_sha1);
 896        /* When the ref did not exist and we are creating it,
 897         * make sure there is no existing ref that is packed
 898         * whose name begins with our refname, nor a ref whose
 899         * name is a proper prefix of our refname.
 900         */
 901        if (missing &&
 902             !is_refname_available(ref, NULL, get_packed_refs(), 0)) {
 903                last_errno = ENOTDIR;
 904                goto error_return;
 905        }
 906
 907        lock->lk = xcalloc(1, sizeof(struct lock_file));
 908
 909        lflags = LOCK_DIE_ON_ERROR;
 910        if (flags & REF_NODEREF) {
 911                ref = orig_ref;
 912                lflags |= LOCK_NODEREF;
 913        }
 914        lock->ref_name = xstrdup(ref);
 915        lock->orig_ref_name = xstrdup(orig_ref);
 916        ref_file = git_path("%s", ref);
 917        if (missing)
 918                lock->force_write = 1;
 919        if ((flags & REF_NODEREF) && (type & REF_ISSYMREF))
 920                lock->force_write = 1;
 921
 922        if (safe_create_leading_directories(ref_file)) {
 923                last_errno = errno;
 924                error("unable to create directory for %s", ref_file);
 925                goto error_return;
 926        }
 927
 928        lock->lock_fd = hold_lock_file_for_update(lock->lk, ref_file, lflags);
 929        return old_sha1 ? verify_lock(lock, old_sha1, mustexist) : lock;
 930
 931 error_return:
 932        unlock_ref(lock);
 933        errno = last_errno;
 934        return NULL;
 935}
 936
 937struct ref_lock *lock_ref_sha1(const char *ref, const unsigned char *old_sha1)
 938{
 939        char refpath[PATH_MAX];
 940        if (check_ref_format(ref))
 941                return NULL;
 942        strcpy(refpath, mkpath("refs/%s", ref));
 943        return lock_ref_sha1_basic(refpath, old_sha1, 0, NULL);
 944}
 945
 946struct ref_lock *lock_any_ref_for_update(const char *ref, const unsigned char *old_sha1, int flags)
 947{
 948        switch (check_ref_format(ref)) {
 949        default:
 950                return NULL;
 951        case 0:
 952        case CHECK_REF_FORMAT_ONELEVEL:
 953                return lock_ref_sha1_basic(ref, old_sha1, flags, NULL);
 954        }
 955}
 956
 957static struct lock_file packlock;
 958
 959static int repack_without_ref(const char *refname)
 960{
 961        struct ref_list *list, *packed_ref_list;
 962        int fd;
 963        int found = 0;
 964
 965        packed_ref_list = get_packed_refs();
 966        for (list = packed_ref_list; list; list = list->next) {
 967                if (!strcmp(refname, list->name)) {
 968                        found = 1;
 969                        break;
 970                }
 971        }
 972        if (!found)
 973                return 0;
 974        fd = hold_lock_file_for_update(&packlock, git_path("packed-refs"), 0);
 975        if (fd < 0) {
 976                unable_to_lock_error(git_path("packed-refs"), errno);
 977                return error("cannot delete '%s' from packed refs", refname);
 978        }
 979
 980        for (list = packed_ref_list; list; list = list->next) {
 981                char line[PATH_MAX + 100];
 982                int len;
 983
 984                if (!strcmp(refname, list->name))
 985                        continue;
 986                len = snprintf(line, sizeof(line), "%s %s\n",
 987                               sha1_to_hex(list->sha1), list->name);
 988                /* this should not happen but just being defensive */
 989                if (len > sizeof(line))
 990                        die("too long a refname '%s'", list->name);
 991                write_or_die(fd, line, len);
 992        }
 993        return commit_lock_file(&packlock);
 994}
 995
 996int delete_ref(const char *refname, const unsigned char *sha1, int delopt)
 997{
 998        struct ref_lock *lock;
 999        int err, i = 0, ret = 0, flag = 0;
1000
1001        lock = lock_ref_sha1_basic(refname, sha1, 0, &flag);
1002        if (!lock)
1003                return 1;
1004        if (!(flag & REF_ISPACKED) || flag & REF_ISSYMREF) {
1005                /* loose */
1006                const char *path;
1007
1008                if (!(delopt & REF_NODEREF)) {
1009                        i = strlen(lock->lk->filename) - 5; /* .lock */
1010                        lock->lk->filename[i] = 0;
1011                        path = lock->lk->filename;
1012                } else {
1013                        path = git_path("%s", refname);
1014                }
1015                err = unlink_or_warn(path);
1016                if (err && errno != ENOENT)
1017                        ret = 1;
1018
1019                if (!(delopt & REF_NODEREF))
1020                        lock->lk->filename[i] = '.';
1021        }
1022        /* removing the loose one could have resurrected an earlier
1023         * packed one.  Also, if it was not loose we need to repack
1024         * without it.
1025         */
1026        ret |= repack_without_ref(refname);
1027
1028        unlink_or_warn(git_path("logs/%s", lock->ref_name));
1029        invalidate_cached_refs();
1030        unlock_ref(lock);
1031        return ret;
1032}
1033
1034int rename_ref(const char *oldref, const char *newref, const char *logmsg)
1035{
1036        static const char renamed_ref[] = "RENAMED-REF";
1037        unsigned char sha1[20], orig_sha1[20];
1038        int flag = 0, logmoved = 0;
1039        struct ref_lock *lock;
1040        struct stat loginfo;
1041        int log = !lstat(git_path("logs/%s", oldref), &loginfo);
1042        const char *symref = NULL;
1043
1044        if (log && S_ISLNK(loginfo.st_mode))
1045                return error("reflog for %s is a symlink", oldref);
1046
1047        symref = resolve_ref(oldref, orig_sha1, 1, &flag);
1048        if (flag & REF_ISSYMREF)
1049                return error("refname %s is a symbolic ref, renaming it is not supported",
1050                        oldref);
1051        if (!symref)
1052                return error("refname %s not found", oldref);
1053
1054        if (!is_refname_available(newref, oldref, get_packed_refs(), 0))
1055                return 1;
1056
1057        if (!is_refname_available(newref, oldref, get_loose_refs(), 0))
1058                return 1;
1059
1060        lock = lock_ref_sha1_basic(renamed_ref, NULL, 0, NULL);
1061        if (!lock)
1062                return error("unable to lock %s", renamed_ref);
1063        lock->force_write = 1;
1064        if (write_ref_sha1(lock, orig_sha1, logmsg))
1065                return error("unable to save current sha1 in %s", renamed_ref);
1066
1067        if (log && rename(git_path("logs/%s", oldref), git_path("tmp-renamed-log")))
1068                return error("unable to move logfile logs/%s to tmp-renamed-log: %s",
1069                        oldref, strerror(errno));
1070
1071        if (delete_ref(oldref, orig_sha1, REF_NODEREF)) {
1072                error("unable to delete old %s", oldref);
1073                goto rollback;
1074        }
1075
1076        if (resolve_ref(newref, sha1, 1, &flag) && delete_ref(newref, sha1, REF_NODEREF)) {
1077                if (errno==EISDIR) {
1078                        if (remove_empty_directories(git_path("%s", newref))) {
1079                                error("Directory not empty: %s", newref);
1080                                goto rollback;
1081                        }
1082                } else {
1083                        error("unable to delete existing %s", newref);
1084                        goto rollback;
1085                }
1086        }
1087
1088        if (log && safe_create_leading_directories(git_path("logs/%s", newref))) {
1089                error("unable to create directory for %s", newref);
1090                goto rollback;
1091        }
1092
1093 retry:
1094        if (log && rename(git_path("tmp-renamed-log"), git_path("logs/%s", newref))) {
1095                if (errno==EISDIR || errno==ENOTDIR) {
1096                        /*
1097                         * rename(a, b) when b is an existing
1098                         * directory ought to result in ISDIR, but
1099                         * Solaris 5.8 gives ENOTDIR.  Sheesh.
1100                         */
1101                        if (remove_empty_directories(git_path("logs/%s", newref))) {
1102                                error("Directory not empty: logs/%s", newref);
1103                                goto rollback;
1104                        }
1105                        goto retry;
1106                } else {
1107                        error("unable to move logfile tmp-renamed-log to logs/%s: %s",
1108                                newref, strerror(errno));
1109                        goto rollback;
1110                }
1111        }
1112        logmoved = log;
1113
1114        lock = lock_ref_sha1_basic(newref, NULL, 0, NULL);
1115        if (!lock) {
1116                error("unable to lock %s for update", newref);
1117                goto rollback;
1118        }
1119        lock->force_write = 1;
1120        hashcpy(lock->old_sha1, orig_sha1);
1121        if (write_ref_sha1(lock, orig_sha1, logmsg)) {
1122                error("unable to write current sha1 into %s", newref);
1123                goto rollback;
1124        }
1125
1126        return 0;
1127
1128 rollback:
1129        lock = lock_ref_sha1_basic(oldref, NULL, 0, NULL);
1130        if (!lock) {
1131                error("unable to lock %s for rollback", oldref);
1132                goto rollbacklog;
1133        }
1134
1135        lock->force_write = 1;
1136        flag = log_all_ref_updates;
1137        log_all_ref_updates = 0;
1138        if (write_ref_sha1(lock, orig_sha1, NULL))
1139                error("unable to write current sha1 into %s", oldref);
1140        log_all_ref_updates = flag;
1141
1142 rollbacklog:
1143        if (logmoved && rename(git_path("logs/%s", newref), git_path("logs/%s", oldref)))
1144                error("unable to restore logfile %s from %s: %s",
1145                        oldref, newref, strerror(errno));
1146        if (!logmoved && log &&
1147            rename(git_path("tmp-renamed-log"), git_path("logs/%s", oldref)))
1148                error("unable to restore logfile %s from tmp-renamed-log: %s",
1149                        oldref, strerror(errno));
1150
1151        return 1;
1152}
1153
1154int close_ref(struct ref_lock *lock)
1155{
1156        if (close_lock_file(lock->lk))
1157                return -1;
1158        lock->lock_fd = -1;
1159        return 0;
1160}
1161
1162int commit_ref(struct ref_lock *lock)
1163{
1164        if (commit_lock_file(lock->lk))
1165                return -1;
1166        lock->lock_fd = -1;
1167        return 0;
1168}
1169
1170void unlock_ref(struct ref_lock *lock)
1171{
1172        /* Do not free lock->lk -- atexit() still looks at them */
1173        if (lock->lk)
1174                rollback_lock_file(lock->lk);
1175        free(lock->ref_name);
1176        free(lock->orig_ref_name);
1177        free(lock);
1178}
1179
1180/*
1181 * copy the reflog message msg to buf, which has been allocated sufficiently
1182 * large, while cleaning up the whitespaces.  Especially, convert LF to space,
1183 * because reflog file is one line per entry.
1184 */
1185static int copy_msg(char *buf, const char *msg)
1186{
1187        char *cp = buf;
1188        char c;
1189        int wasspace = 1;
1190
1191        *cp++ = '\t';
1192        while ((c = *msg++)) {
1193                if (wasspace && isspace(c))
1194                        continue;
1195                wasspace = isspace(c);
1196                if (wasspace)
1197                        c = ' ';
1198                *cp++ = c;
1199        }
1200        while (buf < cp && isspace(cp[-1]))
1201                cp--;
1202        *cp++ = '\n';
1203        return cp - buf;
1204}
1205
1206static int log_ref_write(const char *ref_name, const unsigned char *old_sha1,
1207                         const unsigned char *new_sha1, const char *msg)
1208{
1209        int logfd, written, oflags = O_APPEND | O_WRONLY;
1210        unsigned maxlen, len;
1211        int msglen;
1212        char log_file[PATH_MAX];
1213        char *logrec;
1214        const char *committer;
1215
1216        if (log_all_ref_updates < 0)
1217                log_all_ref_updates = !is_bare_repository();
1218
1219        git_snpath(log_file, sizeof(log_file), "logs/%s", ref_name);
1220
1221        if (log_all_ref_updates &&
1222            (!prefixcmp(ref_name, "refs/heads/") ||
1223             !prefixcmp(ref_name, "refs/remotes/") ||
1224             !strcmp(ref_name, "HEAD"))) {
1225                if (safe_create_leading_directories(log_file) < 0)
1226                        return error("unable to create directory for %s",
1227                                     log_file);
1228                oflags |= O_CREAT;
1229        }
1230
1231        logfd = open(log_file, oflags, 0666);
1232        if (logfd < 0) {
1233                if (!(oflags & O_CREAT) && errno == ENOENT)
1234                        return 0;
1235
1236                if ((oflags & O_CREAT) && errno == EISDIR) {
1237                        if (remove_empty_directories(log_file)) {
1238                                return error("There are still logs under '%s'",
1239                                             log_file);
1240                        }
1241                        logfd = open(log_file, oflags, 0666);
1242                }
1243
1244                if (logfd < 0)
1245                        return error("Unable to append to %s: %s",
1246                                     log_file, strerror(errno));
1247        }
1248
1249        adjust_shared_perm(log_file);
1250
1251        msglen = msg ? strlen(msg) : 0;
1252        committer = git_committer_info(0);
1253        maxlen = strlen(committer) + msglen + 100;
1254        logrec = xmalloc(maxlen);
1255        len = sprintf(logrec, "%s %s %s\n",
1256                      sha1_to_hex(old_sha1),
1257                      sha1_to_hex(new_sha1),
1258                      committer);
1259        if (msglen)
1260                len += copy_msg(logrec + len - 1, msg) - 1;
1261        written = len <= maxlen ? write_in_full(logfd, logrec, len) : -1;
1262        free(logrec);
1263        if (close(logfd) != 0 || written != len)
1264                return error("Unable to append to %s", log_file);
1265        return 0;
1266}
1267
1268static int is_branch(const char *refname)
1269{
1270        return !strcmp(refname, "HEAD") || !prefixcmp(refname, "refs/heads/");
1271}
1272
1273int write_ref_sha1(struct ref_lock *lock,
1274        const unsigned char *sha1, const char *logmsg)
1275{
1276        static char term = '\n';
1277        struct object *o;
1278
1279        if (!lock)
1280                return -1;
1281        if (!lock->force_write && !hashcmp(lock->old_sha1, sha1)) {
1282                unlock_ref(lock);
1283                return 0;
1284        }
1285        o = parse_object(sha1);
1286        if (!o) {
1287                error("Trying to write ref %s with nonexistant object %s",
1288                        lock->ref_name, sha1_to_hex(sha1));
1289                unlock_ref(lock);
1290                return -1;
1291        }
1292        if (o->type != OBJ_COMMIT && is_branch(lock->ref_name)) {
1293                error("Trying to write non-commit object %s to branch %s",
1294                        sha1_to_hex(sha1), lock->ref_name);
1295                unlock_ref(lock);
1296                return -1;
1297        }
1298        if (write_in_full(lock->lock_fd, sha1_to_hex(sha1), 40) != 40 ||
1299            write_in_full(lock->lock_fd, &term, 1) != 1
1300                || close_ref(lock) < 0) {
1301                error("Couldn't write %s", lock->lk->filename);
1302                unlock_ref(lock);
1303                return -1;
1304        }
1305        invalidate_cached_refs();
1306        if (log_ref_write(lock->ref_name, lock->old_sha1, sha1, logmsg) < 0 ||
1307            (strcmp(lock->ref_name, lock->orig_ref_name) &&
1308             log_ref_write(lock->orig_ref_name, lock->old_sha1, sha1, logmsg) < 0)) {
1309                unlock_ref(lock);
1310                return -1;
1311        }
1312        if (strcmp(lock->orig_ref_name, "HEAD") != 0) {
1313                /*
1314                 * Special hack: If a branch is updated directly and HEAD
1315                 * points to it (may happen on the remote side of a push
1316                 * for example) then logically the HEAD reflog should be
1317                 * updated too.
1318                 * A generic solution implies reverse symref information,
1319                 * but finding all symrefs pointing to the given branch
1320                 * would be rather costly for this rare event (the direct
1321                 * update of a branch) to be worth it.  So let's cheat and
1322                 * check with HEAD only which should cover 99% of all usage
1323                 * scenarios (even 100% of the default ones).
1324                 */
1325                unsigned char head_sha1[20];
1326                int head_flag;
1327                const char *head_ref;
1328                head_ref = resolve_ref("HEAD", head_sha1, 1, &head_flag);
1329                if (head_ref && (head_flag & REF_ISSYMREF) &&
1330                    !strcmp(head_ref, lock->ref_name))
1331                        log_ref_write("HEAD", lock->old_sha1, sha1, logmsg);
1332        }
1333        if (commit_ref(lock)) {
1334                error("Couldn't set %s", lock->ref_name);
1335                unlock_ref(lock);
1336                return -1;
1337        }
1338        unlock_ref(lock);
1339        return 0;
1340}
1341
1342int create_symref(const char *ref_target, const char *refs_heads_master,
1343                  const char *logmsg)
1344{
1345        const char *lockpath;
1346        char ref[1000];
1347        int fd, len, written;
1348        char *git_HEAD = git_pathdup("%s", ref_target);
1349        unsigned char old_sha1[20], new_sha1[20];
1350
1351        if (logmsg && read_ref(ref_target, old_sha1))
1352                hashclr(old_sha1);
1353
1354        if (safe_create_leading_directories(git_HEAD) < 0)
1355                return error("unable to create directory for %s", git_HEAD);
1356
1357#ifndef NO_SYMLINK_HEAD
1358        if (prefer_symlink_refs) {
1359                unlink(git_HEAD);
1360                if (!symlink(refs_heads_master, git_HEAD))
1361                        goto done;
1362                fprintf(stderr, "no symlink - falling back to symbolic ref\n");
1363        }
1364#endif
1365
1366        len = snprintf(ref, sizeof(ref), "ref: %s\n", refs_heads_master);
1367        if (sizeof(ref) <= len) {
1368                error("refname too long: %s", refs_heads_master);
1369                goto error_free_return;
1370        }
1371        lockpath = mkpath("%s.lock", git_HEAD);
1372        fd = open(lockpath, O_CREAT | O_EXCL | O_WRONLY, 0666);
1373        if (fd < 0) {
1374                error("Unable to open %s for writing", lockpath);
1375                goto error_free_return;
1376        }
1377        written = write_in_full(fd, ref, len);
1378        if (close(fd) != 0 || written != len) {
1379                error("Unable to write to %s", lockpath);
1380                goto error_unlink_return;
1381        }
1382        if (rename(lockpath, git_HEAD) < 0) {
1383                error("Unable to create %s", git_HEAD);
1384                goto error_unlink_return;
1385        }
1386        if (adjust_shared_perm(git_HEAD)) {
1387                error("Unable to fix permissions on %s", lockpath);
1388        error_unlink_return:
1389                unlink_or_warn(lockpath);
1390        error_free_return:
1391                free(git_HEAD);
1392                return -1;
1393        }
1394
1395#ifndef NO_SYMLINK_HEAD
1396        done:
1397#endif
1398        if (logmsg && !read_ref(refs_heads_master, new_sha1))
1399                log_ref_write(ref_target, old_sha1, new_sha1, logmsg);
1400
1401        free(git_HEAD);
1402        return 0;
1403}
1404
1405static char *ref_msg(const char *line, const char *endp)
1406{
1407        const char *ep;
1408        line += 82;
1409        ep = memchr(line, '\n', endp - line);
1410        if (!ep)
1411                ep = endp;
1412        return xmemdupz(line, ep - line);
1413}
1414
1415int 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)
1416{
1417        const char *logfile, *logdata, *logend, *rec, *lastgt, *lastrec;
1418        char *tz_c;
1419        int logfd, tz, reccnt = 0;
1420        struct stat st;
1421        unsigned long date;
1422        unsigned char logged_sha1[20];
1423        void *log_mapped;
1424        size_t mapsz;
1425
1426        logfile = git_path("logs/%s", ref);
1427        logfd = open(logfile, O_RDONLY, 0);
1428        if (logfd < 0)
1429                die_errno("Unable to read log '%s'", logfile);
1430        fstat(logfd, &st);
1431        if (!st.st_size)
1432                die("Log %s is empty.", logfile);
1433        mapsz = xsize_t(st.st_size);
1434        log_mapped = xmmap(NULL, mapsz, PROT_READ, MAP_PRIVATE, logfd, 0);
1435        logdata = log_mapped;
1436        close(logfd);
1437
1438        lastrec = NULL;
1439        rec = logend = logdata + st.st_size;
1440        while (logdata < rec) {
1441                reccnt++;
1442                if (logdata < rec && *(rec-1) == '\n')
1443                        rec--;
1444                lastgt = NULL;
1445                while (logdata < rec && *(rec-1) != '\n') {
1446                        rec--;
1447                        if (*rec == '>')
1448                                lastgt = rec;
1449                }
1450                if (!lastgt)
1451                        die("Log %s is corrupt.", logfile);
1452                date = strtoul(lastgt + 1, &tz_c, 10);
1453                if (date <= at_time || cnt == 0) {
1454                        tz = strtoul(tz_c, NULL, 10);
1455                        if (msg)
1456                                *msg = ref_msg(rec, logend);
1457                        if (cutoff_time)
1458                                *cutoff_time = date;
1459                        if (cutoff_tz)
1460                                *cutoff_tz = tz;
1461                        if (cutoff_cnt)
1462                                *cutoff_cnt = reccnt - 1;
1463                        if (lastrec) {
1464                                if (get_sha1_hex(lastrec, logged_sha1))
1465                                        die("Log %s is corrupt.", logfile);
1466                                if (get_sha1_hex(rec + 41, sha1))
1467                                        die("Log %s is corrupt.", logfile);
1468                                if (hashcmp(logged_sha1, sha1)) {
1469                                        warning("Log %s has gap after %s.",
1470                                                logfile, show_date(date, tz, DATE_RFC2822));
1471                                }
1472                        }
1473                        else if (date == at_time) {
1474                                if (get_sha1_hex(rec + 41, sha1))
1475                                        die("Log %s is corrupt.", logfile);
1476                        }
1477                        else {
1478                                if (get_sha1_hex(rec + 41, logged_sha1))
1479                                        die("Log %s is corrupt.", logfile);
1480                                if (hashcmp(logged_sha1, sha1)) {
1481                                        warning("Log %s unexpectedly ended on %s.",
1482                                                logfile, show_date(date, tz, DATE_RFC2822));
1483                                }
1484                        }
1485                        munmap(log_mapped, mapsz);
1486                        return 0;
1487                }
1488                lastrec = rec;
1489                if (cnt > 0)
1490                        cnt--;
1491        }
1492
1493        rec = logdata;
1494        while (rec < logend && *rec != '>' && *rec != '\n')
1495                rec++;
1496        if (rec == logend || *rec == '\n')
1497                die("Log %s is corrupt.", logfile);
1498        date = strtoul(rec + 1, &tz_c, 10);
1499        tz = strtoul(tz_c, NULL, 10);
1500        if (get_sha1_hex(logdata, sha1))
1501                die("Log %s is corrupt.", logfile);
1502        if (is_null_sha1(sha1)) {
1503                if (get_sha1_hex(logdata + 41, sha1))
1504                        die("Log %s is corrupt.", logfile);
1505        }
1506        if (msg)
1507                *msg = ref_msg(logdata, logend);
1508        munmap(log_mapped, mapsz);
1509
1510        if (cutoff_time)
1511                *cutoff_time = date;
1512        if (cutoff_tz)
1513                *cutoff_tz = tz;
1514        if (cutoff_cnt)
1515                *cutoff_cnt = reccnt;
1516        return 1;
1517}
1518
1519int for_each_recent_reflog_ent(const char *ref, each_reflog_ent_fn fn, long ofs, void *cb_data)
1520{
1521        const char *logfile;
1522        FILE *logfp;
1523        char buf[1024];
1524        int ret = 0;
1525
1526        logfile = git_path("logs/%s", ref);
1527        logfp = fopen(logfile, "r");
1528        if (!logfp)
1529                return -1;
1530
1531        if (ofs) {
1532                struct stat statbuf;
1533                if (fstat(fileno(logfp), &statbuf) ||
1534                    statbuf.st_size < ofs ||
1535                    fseek(logfp, -ofs, SEEK_END) ||
1536                    fgets(buf, sizeof(buf), logfp)) {
1537                        fclose(logfp);
1538                        return -1;
1539                }
1540        }
1541
1542        while (fgets(buf, sizeof(buf), logfp)) {
1543                unsigned char osha1[20], nsha1[20];
1544                char *email_end, *message;
1545                unsigned long timestamp;
1546                int len, tz;
1547
1548                /* old SP new SP name <email> SP time TAB msg LF */
1549                len = strlen(buf);
1550                if (len < 83 || buf[len-1] != '\n' ||
1551                    get_sha1_hex(buf, osha1) || buf[40] != ' ' ||
1552                    get_sha1_hex(buf + 41, nsha1) || buf[81] != ' ' ||
1553                    !(email_end = strchr(buf + 82, '>')) ||
1554                    email_end[1] != ' ' ||
1555                    !(timestamp = strtoul(email_end + 2, &message, 10)) ||
1556                    !message || message[0] != ' ' ||
1557                    (message[1] != '+' && message[1] != '-') ||
1558                    !isdigit(message[2]) || !isdigit(message[3]) ||
1559                    !isdigit(message[4]) || !isdigit(message[5]))
1560                        continue; /* corrupt? */
1561                email_end[1] = '\0';
1562                tz = strtol(message + 1, NULL, 10);
1563                if (message[6] != '\t')
1564                        message += 6;
1565                else
1566                        message += 7;
1567                ret = fn(osha1, nsha1, buf+82, timestamp, tz, message, cb_data);
1568                if (ret)
1569                        break;
1570        }
1571        fclose(logfp);
1572        return ret;
1573}
1574
1575int for_each_reflog_ent(const char *ref, each_reflog_ent_fn fn, void *cb_data)
1576{
1577        return for_each_recent_reflog_ent(ref, fn, 0, cb_data);
1578}
1579
1580static int do_for_each_reflog(const char *base, each_ref_fn fn, void *cb_data)
1581{
1582        DIR *dir = opendir(git_path("logs/%s", base));
1583        int retval = 0;
1584
1585        if (dir) {
1586                struct dirent *de;
1587                int baselen = strlen(base);
1588                char *log = xmalloc(baselen + 257);
1589
1590                memcpy(log, base, baselen);
1591                if (baselen && base[baselen-1] != '/')
1592                        log[baselen++] = '/';
1593
1594                while ((de = readdir(dir)) != NULL) {
1595                        struct stat st;
1596                        int namelen;
1597
1598                        if (de->d_name[0] == '.')
1599                                continue;
1600                        namelen = strlen(de->d_name);
1601                        if (namelen > 255)
1602                                continue;
1603                        if (has_extension(de->d_name, ".lock"))
1604                                continue;
1605                        memcpy(log + baselen, de->d_name, namelen+1);
1606                        if (stat(git_path("logs/%s", log), &st) < 0)
1607                                continue;
1608                        if (S_ISDIR(st.st_mode)) {
1609                                retval = do_for_each_reflog(log, fn, cb_data);
1610                        } else {
1611                                unsigned char sha1[20];
1612                                if (!resolve_ref(log, sha1, 0, NULL))
1613                                        retval = error("bad ref for %s", log);
1614                                else
1615                                        retval = fn(log, sha1, 0, cb_data);
1616                        }
1617                        if (retval)
1618                                break;
1619                }
1620                free(log);
1621                closedir(dir);
1622        }
1623        else if (*base)
1624                return errno;
1625        return retval;
1626}
1627
1628int for_each_reflog(each_ref_fn fn, void *cb_data)
1629{
1630        return do_for_each_reflog("", fn, cb_data);
1631}
1632
1633int update_ref(const char *action, const char *refname,
1634                const unsigned char *sha1, const unsigned char *oldval,
1635                int flags, enum action_on_err onerr)
1636{
1637        static struct ref_lock *lock;
1638        lock = lock_any_ref_for_update(refname, oldval, flags);
1639        if (!lock) {
1640                const char *str = "Cannot lock the ref '%s'.";
1641                switch (onerr) {
1642                case MSG_ON_ERR: error(str, refname); break;
1643                case DIE_ON_ERR: die(str, refname); break;
1644                case QUIET_ON_ERR: break;
1645                }
1646                return 1;
1647        }
1648        if (write_ref_sha1(lock, sha1, action) < 0) {
1649                const char *str = "Cannot update the ref '%s'.";
1650                switch (onerr) {
1651                case MSG_ON_ERR: error(str, refname); break;
1652                case DIE_ON_ERR: die(str, refname); break;
1653                case QUIET_ON_ERR: break;
1654                }
1655                return 1;
1656        }
1657        return 0;
1658}
1659
1660struct ref *find_ref_by_name(const struct ref *list, const char *name)
1661{
1662        for ( ; list; list = list->next)
1663                if (!strcmp(list->name, name))
1664                        return (struct ref *)list;
1665        return NULL;
1666}
1667
1668/*
1669 * generate a format suitable for scanf from a ref_rev_parse_rules
1670 * rule, that is replace the "%.*s" spec with a "%s" spec
1671 */
1672static void gen_scanf_fmt(char *scanf_fmt, const char *rule)
1673{
1674        char *spec;
1675
1676        spec = strstr(rule, "%.*s");
1677        if (!spec || strstr(spec + 4, "%.*s"))
1678                die("invalid rule in ref_rev_parse_rules: %s", rule);
1679
1680        /* copy all until spec */
1681        strncpy(scanf_fmt, rule, spec - rule);
1682        scanf_fmt[spec - rule] = '\0';
1683        /* copy new spec */
1684        strcat(scanf_fmt, "%s");
1685        /* copy remaining rule */
1686        strcat(scanf_fmt, spec + 4);
1687
1688        return;
1689}
1690
1691char *shorten_unambiguous_ref(const char *ref, int strict)
1692{
1693        int i;
1694        static char **scanf_fmts;
1695        static int nr_rules;
1696        char *short_name;
1697
1698        /* pre generate scanf formats from ref_rev_parse_rules[] */
1699        if (!nr_rules) {
1700                size_t total_len = 0;
1701
1702                /* the rule list is NULL terminated, count them first */
1703                for (; ref_rev_parse_rules[nr_rules]; nr_rules++)
1704                        /* no +1 because strlen("%s") < strlen("%.*s") */
1705                        total_len += strlen(ref_rev_parse_rules[nr_rules]);
1706
1707                scanf_fmts = xmalloc(nr_rules * sizeof(char *) + total_len);
1708
1709                total_len = 0;
1710                for (i = 0; i < nr_rules; i++) {
1711                        scanf_fmts[i] = (char *)&scanf_fmts[nr_rules]
1712                                        + total_len;
1713                        gen_scanf_fmt(scanf_fmts[i], ref_rev_parse_rules[i]);
1714                        total_len += strlen(ref_rev_parse_rules[i]);
1715                }
1716        }
1717
1718        /* bail out if there are no rules */
1719        if (!nr_rules)
1720                return xstrdup(ref);
1721
1722        /* buffer for scanf result, at most ref must fit */
1723        short_name = xstrdup(ref);
1724
1725        /* skip first rule, it will always match */
1726        for (i = nr_rules - 1; i > 0 ; --i) {
1727                int j;
1728                int rules_to_fail = i;
1729                int short_name_len;
1730
1731                if (1 != sscanf(ref, scanf_fmts[i], short_name))
1732                        continue;
1733
1734                short_name_len = strlen(short_name);
1735
1736                /*
1737                 * in strict mode, all (except the matched one) rules
1738                 * must fail to resolve to a valid non-ambiguous ref
1739                 */
1740                if (strict)
1741                        rules_to_fail = nr_rules;
1742
1743                /*
1744                 * check if the short name resolves to a valid ref,
1745                 * but use only rules prior to the matched one
1746                 */
1747                for (j = 0; j < rules_to_fail; j++) {
1748                        const char *rule = ref_rev_parse_rules[j];
1749                        unsigned char short_objectname[20];
1750                        char refname[PATH_MAX];
1751
1752                        /* skip matched rule */
1753                        if (i == j)
1754                                continue;
1755
1756                        /*
1757                         * the short name is ambiguous, if it resolves
1758                         * (with this previous rule) to a valid ref
1759                         * read_ref() returns 0 on success
1760                         */
1761                        mksnpath(refname, sizeof(refname),
1762                                 rule, short_name_len, short_name);
1763                        if (!read_ref(refname, short_objectname))
1764                                break;
1765                }
1766
1767                /*
1768                 * short name is non-ambiguous if all previous rules
1769                 * haven't resolved to a valid ref
1770                 */
1771                if (j == rules_to_fail)
1772                        return short_name;
1773        }
1774
1775        free(short_name);
1776        return xstrdup(ref);
1777}