refs.con commit git-rm: update to saner semantics (9f95069)
   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        memset(&packlock, 0, sizeof(packlock));
 730        fd = hold_lock_file_for_update(&packlock, git_path("packed-refs"), 0);
 731        if (fd < 0)
 732                return error("cannot delete '%s' from packed refs", refname);
 733
 734        for (list = packed_ref_list; list; list = list->next) {
 735                char line[PATH_MAX + 100];
 736                int len;
 737
 738                if (!strcmp(refname, list->name))
 739                        continue;
 740                len = snprintf(line, sizeof(line), "%s %s\n",
 741                               sha1_to_hex(list->sha1), list->name);
 742                /* this should not happen but just being defensive */
 743                if (len > sizeof(line))
 744                        die("too long a refname '%s'", list->name);
 745                write_or_die(fd, line, len);
 746        }
 747        return commit_lock_file(&packlock);
 748}
 749
 750int delete_ref(const char *refname, unsigned char *sha1)
 751{
 752        struct ref_lock *lock;
 753        int err, i, ret = 0, flag = 0;
 754
 755        lock = lock_ref_sha1_basic(refname, sha1, &flag);
 756        if (!lock)
 757                return 1;
 758        if (!(flag & REF_ISPACKED)) {
 759                /* loose */
 760                i = strlen(lock->lk->filename) - 5; /* .lock */
 761                lock->lk->filename[i] = 0;
 762                err = unlink(lock->lk->filename);
 763                if (err) {
 764                        ret = 1;
 765                        error("unlink(%s) failed: %s",
 766                              lock->lk->filename, strerror(errno));
 767                }
 768                lock->lk->filename[i] = '.';
 769        }
 770        /* removing the loose one could have resurrected an earlier
 771         * packed one.  Also, if it was not loose we need to repack
 772         * without it.
 773         */
 774        ret |= repack_without_ref(refname);
 775
 776        err = unlink(lock->log_file);
 777        if (err && errno != ENOENT)
 778                fprintf(stderr, "warning: unlink(%s) failed: %s",
 779                        lock->log_file, strerror(errno));
 780        invalidate_cached_refs();
 781        unlock_ref(lock);
 782        return ret;
 783}
 784
 785int rename_ref(const char *oldref, const char *newref, const char *logmsg)
 786{
 787        static const char renamed_ref[] = "RENAMED-REF";
 788        unsigned char sha1[20], orig_sha1[20];
 789        int flag = 0, logmoved = 0;
 790        struct ref_lock *lock;
 791        struct stat loginfo;
 792        int log = !lstat(git_path("logs/%s", oldref), &loginfo);
 793
 794        if (S_ISLNK(loginfo.st_mode))
 795                return error("reflog for %s is a symlink", oldref);
 796
 797        if (!resolve_ref(oldref, orig_sha1, 1, &flag))
 798                return error("refname %s not found", oldref);
 799
 800        if (!is_refname_available(newref, oldref, get_packed_refs(), 0))
 801                return 1;
 802
 803        if (!is_refname_available(newref, oldref, get_loose_refs(), 0))
 804                return 1;
 805
 806        lock = lock_ref_sha1_basic(renamed_ref, NULL, NULL);
 807        if (!lock)
 808                return error("unable to lock %s", renamed_ref);
 809        lock->force_write = 1;
 810        if (write_ref_sha1(lock, orig_sha1, logmsg))
 811                return error("unable to save current sha1 in %s", renamed_ref);
 812
 813        if (log && rename(git_path("logs/%s", oldref), git_path("tmp-renamed-log")))
 814                return error("unable to move logfile logs/%s to tmp-renamed-log: %s",
 815                        oldref, strerror(errno));
 816
 817        if (delete_ref(oldref, orig_sha1)) {
 818                error("unable to delete old %s", oldref);
 819                goto rollback;
 820        }
 821
 822        if (resolve_ref(newref, sha1, 1, &flag) && delete_ref(newref, sha1)) {
 823                if (errno==EISDIR) {
 824                        if (remove_empty_directories(git_path("%s", newref))) {
 825                                error("Directory not empty: %s", newref);
 826                                goto rollback;
 827                        }
 828                } else {
 829                        error("unable to delete existing %s", newref);
 830                        goto rollback;
 831                }
 832        }
 833
 834        if (log && safe_create_leading_directories(git_path("logs/%s", newref))) {
 835                error("unable to create directory for %s", newref);
 836                goto rollback;
 837        }
 838
 839 retry:
 840        if (log && rename(git_path("tmp-renamed-log"), git_path("logs/%s", newref))) {
 841                if (errno==EISDIR) {
 842                        if (remove_empty_directories(git_path("logs/%s", newref))) {
 843                                error("Directory not empty: logs/%s", newref);
 844                                goto rollback;
 845                        }
 846                        goto retry;
 847                } else {
 848                        error("unable to move logfile tmp-renamed-log to logs/%s: %s",
 849                                newref, strerror(errno));
 850                        goto rollback;
 851                }
 852        }
 853        logmoved = log;
 854
 855        lock = lock_ref_sha1_basic(newref, NULL, NULL);
 856        if (!lock) {
 857                error("unable to lock %s for update", newref);
 858                goto rollback;
 859        }
 860
 861        lock->force_write = 1;
 862        hashcpy(lock->old_sha1, orig_sha1);
 863        if (write_ref_sha1(lock, orig_sha1, logmsg)) {
 864                error("unable to write current sha1 into %s", newref);
 865                goto rollback;
 866        }
 867
 868        if (!strncmp(oldref, "refs/heads/", 11) &&
 869                        !strncmp(newref, "refs/heads/", 11)) {
 870                char oldsection[1024], newsection[1024];
 871
 872                snprintf(oldsection, 1024, "branch.%s", oldref + 11);
 873                snprintf(newsection, 1024, "branch.%s", newref + 11);
 874                if (git_config_rename_section(oldsection, newsection) < 0)
 875                        return 1;
 876        }
 877
 878        return 0;
 879
 880 rollback:
 881        lock = lock_ref_sha1_basic(oldref, NULL, NULL);
 882        if (!lock) {
 883                error("unable to lock %s for rollback", oldref);
 884                goto rollbacklog;
 885        }
 886
 887        lock->force_write = 1;
 888        flag = log_all_ref_updates;
 889        log_all_ref_updates = 0;
 890        if (write_ref_sha1(lock, orig_sha1, NULL))
 891                error("unable to write current sha1 into %s", oldref);
 892        log_all_ref_updates = flag;
 893
 894 rollbacklog:
 895        if (logmoved && rename(git_path("logs/%s", newref), git_path("logs/%s", oldref)))
 896                error("unable to restore logfile %s from %s: %s",
 897                        oldref, newref, strerror(errno));
 898        if (!logmoved && log &&
 899            rename(git_path("tmp-renamed-log"), git_path("logs/%s", oldref)))
 900                error("unable to restore logfile %s from tmp-renamed-log: %s",
 901                        oldref, strerror(errno));
 902
 903        return 1;
 904}
 905
 906void unlock_ref(struct ref_lock *lock)
 907{
 908        if (lock->lock_fd >= 0) {
 909                close(lock->lock_fd);
 910                /* Do not free lock->lk -- atexit() still looks at them */
 911                if (lock->lk)
 912                        rollback_lock_file(lock->lk);
 913        }
 914        free(lock->ref_name);
 915        free(lock->log_file);
 916        free(lock);
 917}
 918
 919static int log_ref_write(struct ref_lock *lock,
 920        const unsigned char *sha1, const char *msg)
 921{
 922        int logfd, written, oflags = O_APPEND | O_WRONLY;
 923        unsigned maxlen, len;
 924        char *logrec;
 925        const char *committer;
 926
 927        if (log_all_ref_updates &&
 928            !strncmp(lock->ref_name, "refs/heads/", 11)) {
 929                if (safe_create_leading_directories(lock->log_file) < 0)
 930                        return error("unable to create directory for %s",
 931                                lock->log_file);
 932                oflags |= O_CREAT;
 933        }
 934
 935        logfd = open(lock->log_file, oflags, 0666);
 936        if (logfd < 0) {
 937                if (!(oflags & O_CREAT) && errno == ENOENT)
 938                        return 0;
 939
 940                if ((oflags & O_CREAT) && errno == EISDIR) {
 941                        if (remove_empty_directories(lock->log_file)) {
 942                                return error("There are still logs under '%s'",
 943                                             lock->log_file);
 944                        }
 945                        logfd = open(lock->log_file, oflags, 0666);
 946                }
 947
 948                if (logfd < 0)
 949                        return error("Unable to append to %s: %s",
 950                                     lock->log_file, strerror(errno));
 951        }
 952
 953        committer = git_committer_info(1);
 954        if (msg) {
 955                maxlen = strlen(committer) + strlen(msg) + 2*40 + 5;
 956                logrec = xmalloc(maxlen);
 957                len = snprintf(logrec, maxlen, "%s %s %s\t%s\n",
 958                        sha1_to_hex(lock->old_sha1),
 959                        sha1_to_hex(sha1),
 960                        committer,
 961                        msg);
 962        }
 963        else {
 964                maxlen = strlen(committer) + 2*40 + 4;
 965                logrec = xmalloc(maxlen);
 966                len = snprintf(logrec, maxlen, "%s %s %s\n",
 967                        sha1_to_hex(lock->old_sha1),
 968                        sha1_to_hex(sha1),
 969                        committer);
 970        }
 971        written = len <= maxlen ? write(logfd, logrec, len) : -1;
 972        free(logrec);
 973        close(logfd);
 974        if (written != len)
 975                return error("Unable to append to %s", lock->log_file);
 976        return 0;
 977}
 978
 979int write_ref_sha1(struct ref_lock *lock,
 980        const unsigned char *sha1, const char *logmsg)
 981{
 982        static char term = '\n';
 983
 984        if (!lock)
 985                return -1;
 986        if (!lock->force_write && !hashcmp(lock->old_sha1, sha1)) {
 987                unlock_ref(lock);
 988                return 0;
 989        }
 990        if (write(lock->lock_fd, sha1_to_hex(sha1), 40) != 40 ||
 991            write(lock->lock_fd, &term, 1) != 1
 992                || close(lock->lock_fd) < 0) {
 993                error("Couldn't write %s", lock->lk->filename);
 994                unlock_ref(lock);
 995                return -1;
 996        }
 997        invalidate_cached_refs();
 998        if (log_ref_write(lock, sha1, logmsg) < 0) {
 999                unlock_ref(lock);
1000                return -1;
1001        }
1002        if (commit_lock_file(lock->lk)) {
1003                error("Couldn't set %s", lock->ref_name);
1004                unlock_ref(lock);
1005                return -1;
1006        }
1007        lock->lock_fd = -1;
1008        unlock_ref(lock);
1009        return 0;
1010}
1011
1012int read_ref_at(const char *ref, unsigned long at_time, int cnt, unsigned char *sha1)
1013{
1014        const char *logfile, *logdata, *logend, *rec, *lastgt, *lastrec;
1015        char *tz_c;
1016        int logfd, tz;
1017        struct stat st;
1018        unsigned long date;
1019        unsigned char logged_sha1[20];
1020
1021        logfile = git_path("logs/%s", ref);
1022        logfd = open(logfile, O_RDONLY, 0);
1023        if (logfd < 0)
1024                die("Unable to read log %s: %s", logfile, strerror(errno));
1025        fstat(logfd, &st);
1026        if (!st.st_size)
1027                die("Log %s is empty.", logfile);
1028        logdata = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, logfd, 0);
1029        close(logfd);
1030
1031        lastrec = NULL;
1032        rec = logend = logdata + st.st_size;
1033        while (logdata < rec) {
1034                if (logdata < rec && *(rec-1) == '\n')
1035                        rec--;
1036                lastgt = NULL;
1037                while (logdata < rec && *(rec-1) != '\n') {
1038                        rec--;
1039                        if (*rec == '>')
1040                                lastgt = rec;
1041                }
1042                if (!lastgt)
1043                        die("Log %s is corrupt.", logfile);
1044                date = strtoul(lastgt + 1, &tz_c, 10);
1045                if (date <= at_time || cnt == 0) {
1046                        if (lastrec) {
1047                                if (get_sha1_hex(lastrec, logged_sha1))
1048                                        die("Log %s is corrupt.", logfile);
1049                                if (get_sha1_hex(rec + 41, sha1))
1050                                        die("Log %s is corrupt.", logfile);
1051                                if (hashcmp(logged_sha1, sha1)) {
1052                                        tz = strtoul(tz_c, NULL, 10);
1053                                        fprintf(stderr,
1054                                                "warning: Log %s has gap after %s.\n",
1055                                                logfile, show_rfc2822_date(date, tz));
1056                                }
1057                        }
1058                        else if (date == at_time) {
1059                                if (get_sha1_hex(rec + 41, sha1))
1060                                        die("Log %s is corrupt.", logfile);
1061                        }
1062                        else {
1063                                if (get_sha1_hex(rec + 41, logged_sha1))
1064                                        die("Log %s is corrupt.", logfile);
1065                                if (hashcmp(logged_sha1, sha1)) {
1066                                        tz = strtoul(tz_c, NULL, 10);
1067                                        fprintf(stderr,
1068                                                "warning: Log %s unexpectedly ended on %s.\n",
1069                                                logfile, show_rfc2822_date(date, tz));
1070                                }
1071                        }
1072                        munmap((void*)logdata, st.st_size);
1073                        return 0;
1074                }
1075                lastrec = rec;
1076                if (cnt > 0)
1077                        cnt--;
1078        }
1079
1080        rec = logdata;
1081        while (rec < logend && *rec != '>' && *rec != '\n')
1082                rec++;
1083        if (rec == logend || *rec == '\n')
1084                die("Log %s is corrupt.", logfile);
1085        date = strtoul(rec + 1, &tz_c, 10);
1086        tz = strtoul(tz_c, NULL, 10);
1087        if (get_sha1_hex(logdata, sha1))
1088                die("Log %s is corrupt.", logfile);
1089        munmap((void*)logdata, st.st_size);
1090        fprintf(stderr, "warning: Log %s only goes back to %s.\n",
1091                logfile, show_rfc2822_date(date, tz));
1092        return 0;
1093}