Andrew's git / gitweb.git / refs.c
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refs.con commit Move initialization of log_all_ref_updates (510c5a8)
   1#include "cache.h"
   2#include "refs.h"
   3#include "object.h"
   4#include "tag.h"
   5
   6/* ISSYMREF=01 and ISPACKED=02 are public interfaces */
   7#define REF_KNOWS_PEELED 04
   8
   9struct ref_list {
  10        struct ref_list *next;
  11        unsigned char flag; /* ISSYMREF? ISPACKED? */
  12        unsigned char sha1[20];
  13        unsigned char peeled[20];
  14        char name[FLEX_ARRAY];
  15};
  16
  17static const char *parse_ref_line(char *line, unsigned char *sha1)
  18{
  19        /*
  20         * 42: the answer to everything.
  21         *
  22         * In this case, it happens to be the answer to
  23         *  40 (length of sha1 hex representation)
  24         *  +1 (space in between hex and name)
  25         *  +1 (newline at the end of the line)
  26         */
  27        int len = strlen(line) - 42;
  28
  29        if (len <= 0)
  30                return NULL;
  31        if (get_sha1_hex(line, sha1) < 0)
  32                return NULL;
  33        if (!isspace(line[40]))
  34                return NULL;
  35        line += 41;
  36        if (isspace(*line))
  37                return NULL;
  38        if (line[len] != '\n')
  39                return NULL;
  40        line[len] = 0;
  41
  42        return line;
  43}
  44
  45static struct ref_list *add_ref(const char *name, const unsigned char *sha1,
  46                                int flag, struct ref_list *list,
  47                                struct ref_list **new_entry)
  48{
  49        int len;
  50        struct ref_list **p = &list, *entry;
  51
  52        /* Find the place to insert the ref into.. */
  53        while ((entry = *p) != NULL) {
  54                int cmp = strcmp(entry->name, name);
  55                if (cmp > 0)
  56                        break;
  57
  58                /* Same as existing entry? */
  59                if (!cmp) {
  60                        if (new_entry)
  61                                *new_entry = entry;
  62                        return list;
  63                }
  64                p = &entry->next;
  65        }
  66
  67        /* Allocate it and add it in.. */
  68        len = strlen(name) + 1;
  69        entry = xmalloc(sizeof(struct ref_list) + len);
  70        hashcpy(entry->sha1, sha1);
  71        hashclr(entry->peeled);
  72        memcpy(entry->name, name, len);
  73        entry->flag = flag;
  74        entry->next = *p;
  75        *p = entry;
  76        if (new_entry)
  77                *new_entry = entry;
  78        return list;
  79}
  80
  81/*
  82 * Future: need to be in "struct repository"
  83 * when doing a full libification.
  84 */
  85struct cached_refs {
  86        char did_loose;
  87        char did_packed;
  88        struct ref_list *loose;
  89        struct ref_list *packed;
  90} cached_refs;
  91
  92static void free_ref_list(struct ref_list *list)
  93{
  94        struct ref_list *next;
  95        for ( ; list; list = next) {
  96                next = list->next;
  97                free(list);
  98        }
  99}
 100
 101static void invalidate_cached_refs(void)
 102{
 103        struct cached_refs *ca = &cached_refs;
 104
 105        if (ca->did_loose && ca->loose)
 106                free_ref_list(ca->loose);
 107        if (ca->did_packed && ca->packed)
 108                free_ref_list(ca->packed);
 109        ca->loose = ca->packed = NULL;
 110        ca->did_loose = ca->did_packed = 0;
 111}
 112
 113static void read_packed_refs(FILE *f, struct cached_refs *cached_refs)
 114{
 115        struct ref_list *list = NULL;
 116        struct ref_list *last = NULL;
 117        char refline[PATH_MAX];
 118        int flag = REF_ISPACKED;
 119
 120        while (fgets(refline, sizeof(refline), f)) {
 121                unsigned char sha1[20];
 122                const char *name;
 123                static const char header[] = "# pack-refs with:";
 124
 125                if (!strncmp(refline, header, sizeof(header)-1)) {
 126                        const char *traits = refline + sizeof(header) - 1;
 127                        if (strstr(traits, " peeled "))
 128                                flag |= REF_KNOWS_PEELED;
 129                        /* perhaps other traits later as well */
 130                        continue;
 131                }
 132
 133                name = parse_ref_line(refline, sha1);
 134                if (name) {
 135                        list = add_ref(name, sha1, flag, list, &last);
 136                        continue;
 137                }
 138                if (last &&
 139                    refline[0] == '^' &&
 140                    strlen(refline) == 42 &&
 141                    refline[41] == '\n' &&
 142                    !get_sha1_hex(refline + 1, sha1))
 143                        hashcpy(last->peeled, sha1);
 144        }
 145        cached_refs->packed = list;
 146}
 147
 148static struct ref_list *get_packed_refs(void)
 149{
 150        if (!cached_refs.did_packed) {
 151                FILE *f = fopen(git_path("packed-refs"), "r");
 152                cached_refs.packed = NULL;
 153                if (f) {
 154                        read_packed_refs(f, &cached_refs);
 155                        fclose(f);
 156                }
 157                cached_refs.did_packed = 1;
 158        }
 159        return cached_refs.packed;
 160}
 161
 162static struct ref_list *get_ref_dir(const char *base, struct ref_list *list)
 163{
 164        DIR *dir = opendir(git_path("%s", base));
 165
 166        if (dir) {
 167                struct dirent *de;
 168                int baselen = strlen(base);
 169                char *ref = xmalloc(baselen + 257);
 170
 171                memcpy(ref, base, baselen);
 172                if (baselen && base[baselen-1] != '/')
 173                        ref[baselen++] = '/';
 174
 175                while ((de = readdir(dir)) != NULL) {
 176                        unsigned char sha1[20];
 177                        struct stat st;
 178                        int flag;
 179                        int namelen;
 180
 181                        if (de->d_name[0] == '.')
 182                                continue;
 183                        namelen = strlen(de->d_name);
 184                        if (namelen > 255)
 185                                continue;
 186                        if (has_extension(de->d_name, ".lock"))
 187                                continue;
 188                        memcpy(ref + baselen, de->d_name, namelen+1);
 189                        if (stat(git_path("%s", ref), &st) < 0)
 190                                continue;
 191                        if (S_ISDIR(st.st_mode)) {
 192                                list = get_ref_dir(ref, list);
 193                                continue;
 194                        }
 195                        if (!resolve_ref(ref, sha1, 1, &flag)) {
 196                                error("%s points nowhere!", ref);
 197                                continue;
 198                        }
 199                        list = add_ref(ref, sha1, flag, list, NULL);
 200                }
 201                free(ref);
 202                closedir(dir);
 203        }
 204        return list;
 205}
 206
 207static struct ref_list *get_loose_refs(void)
 208{
 209        if (!cached_refs.did_loose) {
 210                cached_refs.loose = get_ref_dir("refs", NULL);
 211                cached_refs.did_loose = 1;
 212        }
 213        return cached_refs.loose;
 214}
 215
 216/* We allow "recursive" symbolic refs. Only within reason, though */
 217#define MAXDEPTH 5
 218
 219const char *resolve_ref(const char *ref, unsigned char *sha1, int reading, int *flag)
 220{
 221        int depth = MAXDEPTH, len;
 222        char buffer[256];
 223        static char ref_buffer[256];
 224
 225        if (flag)
 226                *flag = 0;
 227
 228        for (;;) {
 229                const char *path = git_path("%s", ref);
 230                struct stat st;
 231                char *buf;
 232                int fd;
 233
 234                if (--depth < 0)
 235                        return NULL;
 236
 237                /* Special case: non-existing file.
 238                 * Not having the refs/heads/new-branch is OK
 239                 * if we are writing into it, so is .git/HEAD
 240                 * that points at refs/heads/master still to be
 241                 * born.  It is NOT OK if we are resolving for
 242                 * reading.
 243                 */
 244                if (lstat(path, &st) < 0) {
 245                        struct ref_list *list = get_packed_refs();
 246                        while (list) {
 247                                if (!strcmp(ref, list->name)) {
 248                                        hashcpy(sha1, list->sha1);
 249                                        if (flag)
 250                                                *flag |= REF_ISPACKED;
 251                                        return ref;
 252                                }
 253                                list = list->next;
 254                        }
 255                        if (reading || errno != ENOENT)
 256                                return NULL;
 257                        hashclr(sha1);
 258                        return ref;
 259                }
 260
 261                /* Follow "normalized" - ie "refs/.." symlinks by hand */
 262                if (S_ISLNK(st.st_mode)) {
 263                        len = readlink(path, buffer, sizeof(buffer)-1);
 264                        if (len >= 5 && !memcmp("refs/", buffer, 5)) {
 265                                buffer[len] = 0;
 266                                strcpy(ref_buffer, buffer);
 267                                ref = ref_buffer;
 268                                if (flag)
 269                                        *flag |= REF_ISSYMREF;
 270                                continue;
 271                        }
 272                }
 273
 274                /* Is it a directory? */
 275                if (S_ISDIR(st.st_mode)) {
 276                        errno = EISDIR;
 277                        return NULL;
 278                }
 279
 280                /*
 281                 * Anything else, just open it and try to use it as
 282                 * a ref
 283                 */
 284                fd = open(path, O_RDONLY);
 285                if (fd < 0)
 286                        return NULL;
 287                len = read(fd, buffer, sizeof(buffer)-1);
 288                close(fd);
 289
 290                /*
 291                 * Is it a symbolic ref?
 292                 */
 293                if (len < 4 || memcmp("ref:", buffer, 4))
 294                        break;
 295                buf = buffer + 4;
 296                len -= 4;
 297                while (len && isspace(*buf))
 298                        buf++, len--;
 299                while (len && isspace(buf[len-1]))
 300                        len--;
 301                buf[len] = 0;
 302                memcpy(ref_buffer, buf, len + 1);
 303                ref = ref_buffer;
 304                if (flag)
 305                        *flag |= REF_ISSYMREF;
 306        }
 307        if (len < 40 || get_sha1_hex(buffer, sha1))
 308                return NULL;
 309        return ref;
 310}
 311
 312int create_symref(const char *ref_target, const char *refs_heads_master)
 313{
 314        const char *lockpath;
 315        char ref[1000];
 316        int fd, len, written;
 317        const char *git_HEAD = git_path("%s", ref_target);
 318
 319#ifndef NO_SYMLINK_HEAD
 320        if (prefer_symlink_refs) {
 321                unlink(git_HEAD);
 322                if (!symlink(refs_heads_master, git_HEAD))
 323                        return 0;
 324                fprintf(stderr, "no symlink - falling back to symbolic ref\n");
 325        }
 326#endif
 327
 328        len = snprintf(ref, sizeof(ref), "ref: %s\n", refs_heads_master);
 329        if (sizeof(ref) <= len) {
 330                error("refname too long: %s", refs_heads_master);
 331                return -1;
 332        }
 333        lockpath = mkpath("%s.lock", git_HEAD);
 334        fd = open(lockpath, O_CREAT | O_EXCL | O_WRONLY, 0666); 
 335        written = write(fd, ref, len);
 336        close(fd);
 337        if (written != len) {
 338                unlink(lockpath);
 339                error("Unable to write to %s", lockpath);
 340                return -2;
 341        }
 342        if (rename(lockpath, git_HEAD) < 0) {
 343                unlink(lockpath);
 344                error("Unable to create %s", git_HEAD);
 345                return -3;
 346        }
 347        if (adjust_shared_perm(git_HEAD)) {
 348                unlink(lockpath);
 349                error("Unable to fix permissions on %s", lockpath);
 350                return -4;
 351        }
 352        return 0;
 353}
 354
 355int read_ref(const char *ref, unsigned char *sha1)
 356{
 357        if (resolve_ref(ref, sha1, 1, NULL))
 358                return 0;
 359        return -1;
 360}
 361
 362static int do_one_ref(const char *base, each_ref_fn fn, int trim,
 363                      void *cb_data, struct ref_list *entry)
 364{
 365        if (strncmp(base, entry->name, trim))
 366                return 0;
 367        if (is_null_sha1(entry->sha1))
 368                return 0;
 369        if (!has_sha1_file(entry->sha1)) {
 370                error("%s does not point to a valid object!", entry->name);
 371                return 0;
 372        }
 373        return fn(entry->name + trim, entry->sha1, entry->flag, cb_data);
 374}
 375
 376int peel_ref(const char *ref, unsigned char *sha1)
 377{
 378        int flag;
 379        unsigned char base[20];
 380        struct object *o;
 381
 382        if (!resolve_ref(ref, base, 1, &flag))
 383                return -1;
 384
 385        if ((flag & REF_ISPACKED)) {
 386                struct ref_list *list = get_packed_refs();
 387
 388                while (list) {
 389                        if (!strcmp(list->name, ref)) {
 390                                if (list->flag & REF_KNOWS_PEELED) {
 391                                        hashcpy(sha1, list->peeled);
 392                                        return 0;
 393                                }
 394                                /* older pack-refs did not leave peeled ones */
 395                                break;
 396                        }
 397                        list = list->next;
 398                }
 399        }
 400
 401        /* fallback - callers should not call this for unpacked refs */
 402        o = parse_object(base);
 403        if (o->type == OBJ_TAG) {
 404                o = deref_tag(o, ref, 0);
 405                if (o) {
 406                        hashcpy(sha1, o->sha1);
 407                        return 0;
 408                }
 409        }
 410        return -1;
 411}
 412
 413static int do_for_each_ref(const char *base, each_ref_fn fn, int trim,
 414                           void *cb_data)
 415{
 416        int retval;
 417        struct ref_list *packed = get_packed_refs();
 418        struct ref_list *loose = get_loose_refs();
 419
 420        while (packed && loose) {
 421                struct ref_list *entry;
 422                int cmp = strcmp(packed->name, loose->name);
 423                if (!cmp) {
 424                        packed = packed->next;
 425                        continue;
 426                }
 427                if (cmp > 0) {
 428                        entry = loose;
 429                        loose = loose->next;
 430                } else {
 431                        entry = packed;
 432                        packed = packed->next;
 433                }
 434                retval = do_one_ref(base, fn, trim, cb_data, entry);
 435                if (retval)
 436                        return retval;
 437        }
 438
 439        for (packed = packed ? packed : loose; packed; packed = packed->next) {
 440                retval = do_one_ref(base, fn, trim, cb_data, packed);
 441                if (retval)
 442                        return retval;
 443        }
 444        return 0;
 445}
 446
 447int head_ref(each_ref_fn fn, void *cb_data)
 448{
 449        unsigned char sha1[20];
 450        int flag;
 451
 452        if (resolve_ref("HEAD", sha1, 1, &flag))
 453                return fn("HEAD", sha1, flag, cb_data);
 454        return 0;
 455}
 456
 457int for_each_ref(each_ref_fn fn, void *cb_data)
 458{
 459        return do_for_each_ref("refs/", fn, 0, cb_data);
 460}
 461
 462int for_each_tag_ref(each_ref_fn fn, void *cb_data)
 463{
 464        return do_for_each_ref("refs/tags/", fn, 10, cb_data);
 465}
 466
 467int for_each_branch_ref(each_ref_fn fn, void *cb_data)
 468{
 469        return do_for_each_ref("refs/heads/", fn, 11, cb_data);
 470}
 471
 472int for_each_remote_ref(each_ref_fn fn, void *cb_data)
 473{
 474        return do_for_each_ref("refs/remotes/", fn, 13, cb_data);
 475}
 476
 477/* NEEDSWORK: This is only used by ssh-upload and it should go; the
 478 * caller should do resolve_ref or read_ref like everybody else.  Or
 479 * maybe everybody else should use get_ref_sha1() instead of doing
 480 * read_ref().
 481 */
 482int get_ref_sha1(const char *ref, unsigned char *sha1)
 483{
 484        if (check_ref_format(ref))
 485                return -1;
 486        return read_ref(mkpath("refs/%s", ref), sha1);
 487}
 488
 489/*
 490 * Make sure "ref" is something reasonable to have under ".git/refs/";
 491 * We do not like it if:
 492 *
 493 * - any path component of it begins with ".", or
 494 * - it has double dots "..", or
 495 * - it has ASCII control character, "~", "^", ":" or SP, anywhere, or
 496 * - it ends with a "/".
 497 */
 498
 499static inline int bad_ref_char(int ch)
 500{
 501        return (((unsigned) ch) <= ' ' ||
 502                ch == '~' || ch == '^' || ch == ':' ||
 503                /* 2.13 Pattern Matching Notation */
 504                ch == '?' || ch == '*' || ch == '[');
 505}
 506
 507int check_ref_format(const char *ref)
 508{
 509        int ch, level;
 510        const char *cp = ref;
 511
 512        level = 0;
 513        while (1) {
 514                while ((ch = *cp++) == '/')
 515                        ; /* tolerate duplicated slashes */
 516                if (!ch)
 517                        return -1; /* should not end with slashes */
 518
 519                /* we are at the beginning of the path component */
 520                if (ch == '.' || bad_ref_char(ch))
 521                        return -1;
 522
 523                /* scan the rest of the path component */
 524                while ((ch = *cp++) != 0) {
 525                        if (bad_ref_char(ch))
 526                                return -1;
 527                        if (ch == '/')
 528                                break;
 529                        if (ch == '.' && *cp == '.')
 530                                return -1;
 531                }
 532                level++;
 533                if (!ch) {
 534                        if (level < 2)
 535                                return -2; /* at least of form "heads/blah" */
 536                        return 0;
 537                }
 538        }
 539}
 540
 541static struct ref_lock *verify_lock(struct ref_lock *lock,
 542        const unsigned char *old_sha1, int mustexist)
 543{
 544        if (!resolve_ref(lock->ref_name, lock->old_sha1, mustexist, NULL)) {
 545                error("Can't verify ref %s", lock->ref_name);
 546                unlock_ref(lock);
 547                return NULL;
 548        }
 549        if (hashcmp(lock->old_sha1, old_sha1)) {
 550                error("Ref %s is at %s but expected %s", lock->ref_name,
 551                        sha1_to_hex(lock->old_sha1), sha1_to_hex(old_sha1));
 552                unlock_ref(lock);
 553                return NULL;
 554        }
 555        return lock;
 556}
 557
 558static int remove_empty_dir_recursive(char *path, int len)
 559{
 560        DIR *dir = opendir(path);
 561        struct dirent *e;
 562        int ret = 0;
 563
 564        if (!dir)
 565                return -1;
 566        if (path[len-1] != '/')
 567                path[len++] = '/';
 568        while ((e = readdir(dir)) != NULL) {
 569                struct stat st;
 570                int namlen;
 571                if ((e->d_name[0] == '.') &&
 572                    ((e->d_name[1] == 0) ||
 573                     ((e->d_name[1] == '.') && e->d_name[2] == 0)))
 574                        continue; /* "." and ".." */
 575
 576                namlen = strlen(e->d_name);
 577                if ((len + namlen < PATH_MAX) &&
 578                    strcpy(path + len, e->d_name) &&
 579                    !lstat(path, &st) &&
 580                    S_ISDIR(st.st_mode) &&
 581                    !remove_empty_dir_recursive(path, len + namlen))
 582                        continue; /* happy */
 583
 584                /* path too long, stat fails, or non-directory still exists */
 585                ret = -1;
 586                break;
 587        }
 588        closedir(dir);
 589        if (!ret) {
 590                path[len] = 0;
 591                ret = rmdir(path);
 592        }
 593        return ret;
 594}
 595
 596static int remove_empty_directories(char *file)
 597{
 598        /* we want to create a file but there is a directory there;
 599         * if that is an empty directory (or a directory that contains
 600         * only empty directories), remove them.
 601         */
 602        char path[PATH_MAX];
 603        int len = strlen(file);
 604
 605        if (len >= PATH_MAX) /* path too long ;-) */
 606                return -1;
 607        strcpy(path, file);
 608        return remove_empty_dir_recursive(path, len);
 609}
 610
 611static int is_refname_available(const char *ref, const char *oldref,
 612                                struct ref_list *list, int quiet)
 613{
 614        int namlen = strlen(ref); /* e.g. 'foo/bar' */
 615        while (list) {
 616                /* list->name could be 'foo' or 'foo/bar/baz' */
 617                if (!oldref || strcmp(oldref, list->name)) {
 618                        int len = strlen(list->name);
 619                        int cmplen = (namlen < len) ? namlen : len;
 620                        const char *lead = (namlen < len) ? list->name : ref;
 621                        if (!strncmp(ref, list->name, cmplen) &&
 622                            lead[cmplen] == '/') {
 623                                if (!quiet)
 624                                        error("'%s' exists; cannot create '%s'",
 625                                              list->name, ref);
 626                                return 0;
 627                        }
 628                }
 629                list = list->next;
 630        }
 631        return 1;
 632}
 633
 634static struct ref_lock *lock_ref_sha1_basic(const char *ref, const unsigned char *old_sha1, int *flag)
 635{
 636        char *ref_file;
 637        const char *orig_ref = ref;
 638        struct ref_lock *lock;
 639        struct stat st;
 640        int last_errno = 0;
 641        int mustexist = (old_sha1 && !is_null_sha1(old_sha1));
 642
 643        lock = xcalloc(1, sizeof(struct ref_lock));
 644        lock->lock_fd = -1;
 645
 646        ref = resolve_ref(ref, lock->old_sha1, mustexist, flag);
 647        if (!ref && errno == EISDIR) {
 648                /* we are trying to lock foo but we used to
 649                 * have foo/bar which now does not exist;
 650                 * it is normal for the empty directory 'foo'
 651                 * to remain.
 652                 */
 653                ref_file = git_path("%s", orig_ref);
 654                if (remove_empty_directories(ref_file)) {
 655                        last_errno = errno;
 656                        error("there are still refs under '%s'", orig_ref);
 657                        goto error_return;
 658                }
 659                ref = resolve_ref(orig_ref, lock->old_sha1, mustexist, flag);
 660        }
 661        if (!ref) {
 662                last_errno = errno;
 663                error("unable to resolve reference %s: %s",
 664                        orig_ref, strerror(errno));
 665                goto error_return;
 666        }
 667        /* When the ref did not exist and we are creating it,
 668         * make sure there is no existing ref that is packed
 669         * whose name begins with our refname, nor a ref whose
 670         * name is a proper prefix of our refname.
 671         */
 672        if (is_null_sha1(lock->old_sha1) &&
 673            !is_refname_available(ref, NULL, get_packed_refs(), 0))
 674                goto error_return;
 675
 676        lock->lk = xcalloc(1, sizeof(struct lock_file));
 677
 678        lock->ref_name = xstrdup(ref);
 679        lock->log_file = xstrdup(git_path("logs/%s", ref));
 680        ref_file = git_path("%s", ref);
 681        lock->force_write = lstat(ref_file, &st) && errno == ENOENT;
 682
 683        if (safe_create_leading_directories(ref_file)) {
 684                last_errno = errno;
 685                error("unable to create directory for %s", ref_file);
 686                goto error_return;
 687        }
 688        lock->lock_fd = hold_lock_file_for_update(lock->lk, ref_file, 1);
 689
 690        return old_sha1 ? verify_lock(lock, old_sha1, mustexist) : lock;
 691
 692 error_return:
 693        unlock_ref(lock);
 694        errno = last_errno;
 695        return NULL;
 696}
 697
 698struct ref_lock *lock_ref_sha1(const char *ref, const unsigned char *old_sha1)
 699{
 700        char refpath[PATH_MAX];
 701        if (check_ref_format(ref))
 702                return NULL;
 703        strcpy(refpath, mkpath("refs/%s", ref));
 704        return lock_ref_sha1_basic(refpath, old_sha1, NULL);
 705}
 706
 707struct ref_lock *lock_any_ref_for_update(const char *ref, const unsigned char *old_sha1)
 708{
 709        return lock_ref_sha1_basic(ref, old_sha1, NULL);
 710}
 711
 712static struct lock_file packlock;
 713
 714static int repack_without_ref(const char *refname)
 715{
 716        struct ref_list *list, *packed_ref_list;
 717        int fd;
 718        int found = 0;
 719
 720        packed_ref_list = get_packed_refs();
 721        for (list = packed_ref_list; list; list = list->next) {
 722                if (!strcmp(refname, list->name)) {
 723                        found = 1;
 724                        break;
 725                }
 726        }
 727        if (!found)
 728                return 0;
 729        fd = hold_lock_file_for_update(&packlock, git_path("packed-refs"), 0);
 730        if (fd < 0)
 731                return error("cannot delete '%s' from packed refs", refname);
 732
 733        for (list = packed_ref_list; list; list = list->next) {
 734                char line[PATH_MAX + 100];
 735                int len;
 736
 737                if (!strcmp(refname, list->name))
 738                        continue;
 739                len = snprintf(line, sizeof(line), "%s %s\n",
 740                               sha1_to_hex(list->sha1), list->name);
 741                /* this should not happen but just being defensive */
 742                if (len > sizeof(line))
 743                        die("too long a refname '%s'", list->name);
 744                write_or_die(fd, line, len);
 745        }
 746        return commit_lock_file(&packlock);
 747}
 748
 749int delete_ref(const char *refname, unsigned char *sha1)
 750{
 751        struct ref_lock *lock;
 752        int err, i, ret = 0, flag = 0;
 753
 754        lock = lock_ref_sha1_basic(refname, sha1, &flag);
 755        if (!lock)
 756                return 1;
 757        if (!(flag & REF_ISPACKED)) {
 758                /* loose */
 759                i = strlen(lock->lk->filename) - 5; /* .lock */
 760                lock->lk->filename[i] = 0;
 761                err = unlink(lock->lk->filename);
 762                if (err) {
 763                        ret = 1;
 764                        error("unlink(%s) failed: %s",
 765                              lock->lk->filename, strerror(errno));
 766                }
 767                lock->lk->filename[i] = '.';
 768        }
 769        /* removing the loose one could have resurrected an earlier
 770         * packed one.  Also, if it was not loose we need to repack
 771         * without it.
 772         */
 773        ret |= repack_without_ref(refname);
 774
 775        err = unlink(lock->log_file);
 776        if (err && errno != ENOENT)
 777                fprintf(stderr, "warning: unlink(%s) failed: %s",
 778                        lock->log_file, strerror(errno));
 779        invalidate_cached_refs();
 780        unlock_ref(lock);
 781        return ret;
 782}
 783
 784int rename_ref(const char *oldref, const char *newref, const char *logmsg)
 785{
 786        static const char renamed_ref[] = "RENAMED-REF";
 787        unsigned char sha1[20], orig_sha1[20];
 788        int flag = 0, logmoved = 0;
 789        struct ref_lock *lock;
 790        struct stat loginfo;
 791        int log = !lstat(git_path("logs/%s", oldref), &loginfo);
 792
 793        if (S_ISLNK(loginfo.st_mode))
 794                return error("reflog for %s is a symlink", oldref);
 795
 796        if (!resolve_ref(oldref, orig_sha1, 1, &flag))
 797                return error("refname %s not found", oldref);
 798
 799        if (!is_refname_available(newref, oldref, get_packed_refs(), 0))
 800                return 1;
 801
 802        if (!is_refname_available(newref, oldref, get_loose_refs(), 0))
 803                return 1;
 804
 805        lock = lock_ref_sha1_basic(renamed_ref, NULL, NULL);
 806        if (!lock)
 807                return error("unable to lock %s", renamed_ref);
 808        lock->force_write = 1;
 809        if (write_ref_sha1(lock, orig_sha1, logmsg))
 810                return error("unable to save current sha1 in %s", renamed_ref);
 811
 812        if (log && rename(git_path("logs/%s", oldref), git_path("tmp-renamed-log")))
 813                return error("unable to move logfile logs/%s to tmp-renamed-log: %s",
 814                        oldref, strerror(errno));
 815
 816        if (delete_ref(oldref, orig_sha1)) {
 817                error("unable to delete old %s", oldref);
 818                goto rollback;
 819        }
 820
 821        if (resolve_ref(newref, sha1, 1, &flag) && delete_ref(newref, sha1)) {
 822                if (errno==EISDIR) {
 823                        if (remove_empty_directories(git_path("%s", newref))) {
 824                                error("Directory not empty: %s", newref);
 825                                goto rollback;
 826                        }
 827                } else {
 828                        error("unable to delete existing %s", newref);
 829                        goto rollback;
 830                }
 831        }
 832
 833        if (log && safe_create_leading_directories(git_path("logs/%s", newref))) {
 834                error("unable to create directory for %s", newref);
 835                goto rollback;
 836        }
 837
 838 retry:
 839        if (log && rename(git_path("tmp-renamed-log"), git_path("logs/%s", newref))) {
 840                if (errno==EISDIR) {
 841                        if (remove_empty_directories(git_path("logs/%s", newref))) {
 842                                error("Directory not empty: logs/%s", newref);
 843                                goto rollback;
 844                        }
 845                        goto retry;
 846                } else {
 847                        error("unable to move logfile tmp-renamed-log to logs/%s: %s",
 848                                newref, strerror(errno));
 849                        goto rollback;
 850                }
 851        }
 852        logmoved = log;
 853
 854        lock = lock_ref_sha1_basic(newref, NULL, NULL);
 855        if (!lock) {
 856                error("unable to lock %s for update", newref);
 857                goto rollback;
 858        }
 859
 860        lock->force_write = 1;
 861        hashcpy(lock->old_sha1, orig_sha1);
 862        if (write_ref_sha1(lock, orig_sha1, logmsg)) {
 863                error("unable to write current sha1 into %s", newref);
 864                goto rollback;
 865        }
 866
 867        if (!strncmp(oldref, "refs/heads/", 11) &&
 868                        !strncmp(newref, "refs/heads/", 11)) {
 869                char oldsection[1024], newsection[1024];
 870
 871                snprintf(oldsection, 1024, "branch.%s", oldref + 11);
 872                snprintf(newsection, 1024, "branch.%s", newref + 11);
 873                if (git_config_rename_section(oldsection, newsection) < 0)
 874                        return 1;
 875        }
 876
 877        return 0;
 878
 879 rollback:
 880        lock = lock_ref_sha1_basic(oldref, NULL, NULL);
 881        if (!lock) {
 882                error("unable to lock %s for rollback", oldref);
 883                goto rollbacklog;
 884        }
 885
 886        lock->force_write = 1;
 887        flag = log_all_ref_updates;
 888        log_all_ref_updates = 0;
 889        if (write_ref_sha1(lock, orig_sha1, NULL))
 890                error("unable to write current sha1 into %s", oldref);
 891        log_all_ref_updates = flag;
 892
 893 rollbacklog:
 894        if (logmoved && rename(git_path("logs/%s", newref), git_path("logs/%s", oldref)))
 895                error("unable to restore logfile %s from %s: %s",
 896                        oldref, newref, strerror(errno));
 897        if (!logmoved && log &&
 898            rename(git_path("tmp-renamed-log"), git_path("logs/%s", oldref)))
 899                error("unable to restore logfile %s from tmp-renamed-log: %s",
 900                        oldref, strerror(errno));
 901
 902        return 1;
 903}
 904
 905void unlock_ref(struct ref_lock *lock)
 906{
 907        if (lock->lock_fd >= 0) {
 908                close(lock->lock_fd);
 909                /* Do not free lock->lk -- atexit() still looks at them */
 910                if (lock->lk)
 911                        rollback_lock_file(lock->lk);
 912        }
 913        free(lock->ref_name);
 914        free(lock->log_file);
 915        free(lock);
 916}
 917
 918static int log_ref_write(struct ref_lock *lock,
 919        const unsigned char *sha1, const char *msg)
 920{
 921        int logfd, written, oflags = O_APPEND | O_WRONLY;
 922        unsigned maxlen, len;
 923        char *logrec;
 924        const char *committer;
 925
 926        if (log_all_ref_updates < 0)
 927                log_all_ref_updates = !is_bare_git_dir(get_git_dir());
 928
 929        if (log_all_ref_updates &&
 930            (!strncmp(lock->ref_name, "refs/heads/", 11) ||
 931             !strncmp(lock->ref_name, "refs/remotes/", 13))) {
 932                if (safe_create_leading_directories(lock->log_file) < 0)
 933                        return error("unable to create directory for %s",
 934                                lock->log_file);
 935                oflags |= O_CREAT;
 936        }
 937
 938        logfd = open(lock->log_file, oflags, 0666);
 939        if (logfd < 0) {
 940                if (!(oflags & O_CREAT) && errno == ENOENT)
 941                        return 0;
 942
 943                if ((oflags & O_CREAT) && errno == EISDIR) {
 944                        if (remove_empty_directories(lock->log_file)) {
 945                                return error("There are still logs under '%s'",
 946                                             lock->log_file);
 947                        }
 948                        logfd = open(lock->log_file, oflags, 0666);
 949                }
 950
 951                if (logfd < 0)
 952                        return error("Unable to append to %s: %s",
 953                                     lock->log_file, strerror(errno));
 954        }
 955
 956        committer = git_committer_info(1);
 957        if (msg) {
 958                maxlen = strlen(committer) + strlen(msg) + 2*40 + 5;
 959                logrec = xmalloc(maxlen);
 960                len = snprintf(logrec, maxlen, "%s %s %s\t%s\n",
 961                        sha1_to_hex(lock->old_sha1),
 962                        sha1_to_hex(sha1),
 963                        committer,
 964                        msg);
 965        }
 966        else {
 967                maxlen = strlen(committer) + 2*40 + 4;
 968                logrec = xmalloc(maxlen);
 969                len = snprintf(logrec, maxlen, "%s %s %s\n",
 970                        sha1_to_hex(lock->old_sha1),
 971                        sha1_to_hex(sha1),
 972                        committer);
 973        }
 974        written = len <= maxlen ? write(logfd, logrec, len) : -1;
 975        free(logrec);
 976        close(logfd);
 977        if (written != len)
 978                return error("Unable to append to %s", lock->log_file);
 979        return 0;
 980}
 981
 982int write_ref_sha1(struct ref_lock *lock,
 983        const unsigned char *sha1, const char *logmsg)
 984{
 985        static char term = '\n';
 986
 987        if (!lock)
 988                return -1;
 989        if (!lock->force_write && !hashcmp(lock->old_sha1, sha1)) {
 990                unlock_ref(lock);
 991                return 0;
 992        }
 993        if (write(lock->lock_fd, sha1_to_hex(sha1), 40) != 40 ||
 994            write(lock->lock_fd, &term, 1) != 1
 995                || close(lock->lock_fd) < 0) {
 996                error("Couldn't write %s", lock->lk->filename);
 997                unlock_ref(lock);
 998                return -1;
 999        }
1000        invalidate_cached_refs();
1001        if (log_ref_write(lock, sha1, logmsg) < 0) {
1002                unlock_ref(lock);
1003                return -1;
1004        }
1005        if (commit_lock_file(lock->lk)) {
1006                error("Couldn't set %s", lock->ref_name);
1007                unlock_ref(lock);
1008                return -1;
1009        }
1010        lock->lock_fd = -1;
1011        unlock_ref(lock);
1012        return 0;
1013}
1014
1015int read_ref_at(const char *ref, unsigned long at_time, int cnt, unsigned char *sha1)
1016{
1017        const char *logfile, *logdata, *logend, *rec, *lastgt, *lastrec;
1018        char *tz_c;
1019        int logfd, tz, reccnt = 0;
1020        struct stat st;
1021        unsigned long date;
1022        unsigned char logged_sha1[20];
1023
1024        logfile = git_path("logs/%s", ref);
1025        logfd = open(logfile, O_RDONLY, 0);
1026        if (logfd < 0)
1027                die("Unable to read log %s: %s", logfile, strerror(errno));
1028        fstat(logfd, &st);
1029        if (!st.st_size)
1030                die("Log %s is empty.", logfile);
1031        logdata = xmmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, logfd, 0);
1032        close(logfd);
1033
1034        lastrec = NULL;
1035        rec = logend = logdata + st.st_size;
1036        while (logdata < rec) {
1037                reccnt++;
1038                if (logdata < rec && *(rec-1) == '\n')
1039                        rec--;
1040                lastgt = NULL;
1041                while (logdata < rec && *(rec-1) != '\n') {
1042                        rec--;
1043                        if (*rec == '>')
1044                                lastgt = rec;
1045                }
1046                if (!lastgt)
1047                        die("Log %s is corrupt.", logfile);
1048                date = strtoul(lastgt + 1, &tz_c, 10);
1049                if (date <= at_time || cnt == 0) {
1050                        if (lastrec) {
1051                                if (get_sha1_hex(lastrec, logged_sha1))
1052                                        die("Log %s is corrupt.", logfile);
1053                                if (get_sha1_hex(rec + 41, sha1))
1054                                        die("Log %s is corrupt.", logfile);
1055                                if (hashcmp(logged_sha1, sha1)) {
1056                                        tz = strtoul(tz_c, NULL, 10);
1057                                        fprintf(stderr,
1058                                                "warning: Log %s has gap after %s.\n",
1059                                                logfile, show_rfc2822_date(date, tz));
1060                                }
1061                        }
1062                        else if (date == at_time) {
1063                                if (get_sha1_hex(rec + 41, sha1))
1064                                        die("Log %s is corrupt.", logfile);
1065                        }
1066                        else {
1067                                if (get_sha1_hex(rec + 41, logged_sha1))
1068                                        die("Log %s is corrupt.", logfile);
1069                                if (hashcmp(logged_sha1, sha1)) {
1070                                        tz = strtoul(tz_c, NULL, 10);
1071                                        fprintf(stderr,
1072                                                "warning: Log %s unexpectedly ended on %s.\n",
1073                                                logfile, show_rfc2822_date(date, tz));
1074                                }
1075                        }
1076                        munmap((void*)logdata, st.st_size);
1077                        return 0;
1078                }
1079                lastrec = rec;
1080                if (cnt > 0)
1081                        cnt--;
1082        }
1083
1084        rec = logdata;
1085        while (rec < logend && *rec != '>' && *rec != '\n')
1086                rec++;
1087        if (rec == logend || *rec == '\n')
1088                die("Log %s is corrupt.", logfile);
1089        date = strtoul(rec + 1, &tz_c, 10);
1090        tz = strtoul(tz_c, NULL, 10);
1091        if (get_sha1_hex(logdata, sha1))
1092                die("Log %s is corrupt.", logfile);
1093        munmap((void*)logdata, st.st_size);
1094        if (at_time)
1095                fprintf(stderr, "warning: Log %s only goes back to %s.\n",
1096                        logfile, show_rfc2822_date(date, tz));
1097        else
1098                fprintf(stderr, "warning: Log %s only has %d entries.\n",
1099                        logfile, reccnt);
1100        return 0;
1101}
1102
1103void for_each_reflog_ent(const char *ref, each_reflog_ent_fn fn, void *cb_data)
1104{
1105        const char *logfile;
1106        FILE *logfp;
1107        char buf[1024];
1108
1109        logfile = git_path("logs/%s", ref);
1110        logfp = fopen(logfile, "r");
1111        if (!logfp)
1112                return;
1113        while (fgets(buf, sizeof(buf), logfp)) {
1114                unsigned char osha1[20], nsha1[20];
1115                int len;
1116
1117                /* old SP new SP name <email> SP time TAB msg LF */
1118                len = strlen(buf);
1119                if (len < 83 || buf[len-1] != '\n' ||
1120                    get_sha1_hex(buf, osha1) || buf[40] != ' ' ||
1121                    get_sha1_hex(buf + 41, nsha1) || buf[81] != ' ')
1122                        continue; /* corrupt? */
1123                fn(osha1, nsha1, buf+82, cb_data);
1124        }
1125        fclose(logfp);
1126}
1127