refs.c

   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
   9 struct 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
  17 static 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
  45 static 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  */
  85 struct cached_refs {
  86         char did_loose;
  87         char did_packed;
  88         struct ref_list *loose;
  89         struct ref_list *packed;
  90 } cached_refs;
  91
  92 static 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
 101 static 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
 113 static 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
 148 static 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
 162 static 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
 207 static 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
 219 const 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_in_full(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
 312 int 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_in_full(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         unlink(git_HEAD);
 343         if (rename(lockpath, git_HEAD) < 0) {
 344                 unlink(lockpath);
 345                 error("Unable to create %s", git_HEAD);
 346                 return -3;
 347         }
 348         if (adjust_shared_perm(git_HEAD)) {
 349                 unlink(lockpath);
 350                 error("Unable to fix permissions on %s", lockpath);
 351                 return -4;
 352         }
 353         return 0;
 354 }
 355
 356 int read_ref(const char *ref, unsigned char *sha1)
 357 {
 358         if (resolve_ref(ref, sha1, 1, NULL))
 359                 return 0;
 360         return -1;
 361 }
 362
 363 static int do_one_ref(const char *base, each_ref_fn fn, int trim,
 364                       void *cb_data, struct ref_list *entry)
 365 {
 366         if (strncmp(base, entry->name, trim))
 367                 return 0;
 368         if (is_null_sha1(entry->sha1))
 369                 return 0;
 370         if (!has_sha1_file(entry->sha1)) {
 371                 error("%s does not point to a valid object!", entry->name);
 372                 return 0;
 373         }
 374         return fn(entry->name + trim, entry->sha1, entry->flag, cb_data);
 375 }
 376
 377 int peel_ref(const char *ref, unsigned char *sha1)
 378 {
 379         int flag;
 380         unsigned char base[20];
 381         struct object *o;
 382
 383         if (!resolve_ref(ref, base, 1, &flag))
 384                 return -1;
 385
 386         if ((flag & REF_ISPACKED)) {
 387                 struct ref_list *list = get_packed_refs();
 388
 389                 while (list) {
 390                         if (!strcmp(list->name, ref)) {
 391                                 if (list->flag & REF_KNOWS_PEELED) {
 392                                         hashcpy(sha1, list->peeled);
 393                                         return 0;
 394                                 }
 395                                 /* older pack-refs did not leave peeled ones */
 396                                 break;
 397                         }
 398                         list = list->next;
 399                 }
 400         }
 401
 402         /* fallback - callers should not call this for unpacked refs */
 403         o = parse_object(base);
 404         if (o->type == OBJ_TAG) {
 405                 o = deref_tag(o, ref, 0);
 406                 if (o) {
 407                         hashcpy(sha1, o->sha1);
 408                         return 0;
 409                 }
 410         }
 411         return -1;
 412 }
 413
 414 static int do_for_each_ref(const char *base, each_ref_fn fn, int trim,
 415                            void *cb_data)
 416 {
 417         int retval;
 418         struct ref_list *packed = get_packed_refs();
 419         struct ref_list *loose = get_loose_refs();
 420
 421         while (packed && loose) {
 422                 struct ref_list *entry;
 423                 int cmp = strcmp(packed->name, loose->name);
 424                 if (!cmp) {
 425                         packed = packed->next;
 426                         continue;
 427                 }
 428                 if (cmp > 0) {
 429                         entry = loose;
 430                         loose = loose->next;
 431                 } else {
 432                         entry = packed;
 433                         packed = packed->next;
 434                 }
 435                 retval = do_one_ref(base, fn, trim, cb_data, entry);
 436                 if (retval)
 437                         return retval;
 438         }
 439
 440         for (packed = packed ? packed : loose; packed; packed = packed->next) {
 441                 retval = do_one_ref(base, fn, trim, cb_data, packed);
 442                 if (retval)
 443                         return retval;
 444         }
 445         return 0;
 446 }
 447
 448 int head_ref(each_ref_fn fn, void *cb_data)
 449 {
 450         unsigned char sha1[20];
 451         int flag;
 452
 453         if (resolve_ref("HEAD", sha1, 1, &flag))
 454                 return fn("HEAD", sha1, flag, cb_data);
 455         return 0;
 456 }
 457
 458 int for_each_ref(each_ref_fn fn, void *cb_data)
 459 {
 460         return do_for_each_ref("refs/", fn, 0, cb_data);
 461 }
 462
 463 int for_each_tag_ref(each_ref_fn fn, void *cb_data)
 464 {
 465         return do_for_each_ref("refs/tags/", fn, 10, cb_data);
 466 }
 467
 468 int for_each_branch_ref(each_ref_fn fn, void *cb_data)
 469 {
 470         return do_for_each_ref("refs/heads/", fn, 11, cb_data);
 471 }
 472
 473 int for_each_remote_ref(each_ref_fn fn, void *cb_data)
 474 {
 475         return do_for_each_ref("refs/remotes/", fn, 13, cb_data);
 476 }
 477
 478 /* NEEDSWORK: This is only used by ssh-upload and it should go; the
 479  * caller should do resolve_ref or read_ref like everybody else.  Or
 480  * maybe everybody else should use get_ref_sha1() instead of doing
 481  * read_ref().
 482  */
 483 int get_ref_sha1(const char *ref, unsigned char *sha1)
 484 {
 485         if (check_ref_format(ref))
 486                 return -1;
 487         return read_ref(mkpath("refs/%s", ref), sha1);
 488 }
 489
 490 /*
 491  * Make sure "ref" is something reasonable to have under ".git/refs/";
 492  * We do not like it if:
 493  *
 494  * - any path component of it begins with ".", or
 495  * - it has double dots "..", or
 496  * - it has ASCII control character, "~", "^", ":" or SP, anywhere, or
 497  * - it ends with a "/".
 498  */
 499
 500 static inline int bad_ref_char(int ch)
 501 {
 502         return (((unsigned) ch) <= ' ' ||
 503                 ch == '~' || ch == '^' || ch == ':' ||
 504                 /* 2.13 Pattern Matching Notation */
 505                 ch == '?' || ch == '*' || ch == '[');
 506 }
 507
 508 int check_ref_format(const char *ref)
 509 {
 510         int ch, level;
 511         const char *cp = ref;
 512
 513         level = 0;
 514         while (1) {
 515                 while ((ch = *cp++) == '/')
 516                         ; /* tolerate duplicated slashes */
 517                 if (!ch)
 518                         return -1; /* should not end with slashes */
 519
 520                 /* we are at the beginning of the path component */
 521                 if (ch == '.' || bad_ref_char(ch))
 522                         return -1;
 523
 524                 /* scan the rest of the path component */
 525                 while ((ch = *cp++) != 0) {
 526                         if (bad_ref_char(ch))
 527                                 return -1;
 528                         if (ch == '/')
 529                                 break;
 530                         if (ch == '.' && *cp == '.')
 531                                 return -1;
 532                 }
 533                 level++;
 534                 if (!ch) {
 535                         if (level < 2)
 536                                 return -2; /* at least of form "heads/blah" */
 537                         return 0;
 538                 }
 539         }
 540 }
 541
 542 static struct ref_lock *verify_lock(struct ref_lock *lock,
 543         const unsigned char *old_sha1, int mustexist)
 544 {
 545         if (!resolve_ref(lock->ref_name, lock->old_sha1, mustexist, NULL)) {
 546                 error("Can't verify ref %s", lock->ref_name);
 547                 unlock_ref(lock);
 548                 return NULL;
 549         }
 550         if (hashcmp(lock->old_sha1, old_sha1)) {
 551                 error("Ref %s is at %s but expected %s", lock->ref_name,
 552                         sha1_to_hex(lock->old_sha1), sha1_to_hex(old_sha1));
 553                 unlock_ref(lock);
 554                 return NULL;
 555         }
 556         return lock;
 557 }
 558
 559 static int remove_empty_dir_recursive(char *path, int len)
 560 {
 561         DIR *dir = opendir(path);
 562         struct dirent *e;
 563         int ret = 0;
 564
 565         if (!dir)
 566                 return -1;
 567         if (path[len-1] != '/')
 568                 path[len++] = '/';
 569         while ((e = readdir(dir)) != NULL) {
 570                 struct stat st;
 571                 int namlen;
 572                 if ((e->d_name[0] == '.') &&
 573                     ((e->d_name[1] == 0) ||
 574                      ((e->d_name[1] == '.') && e->d_name[2] == 0)))
 575                         continue; /* "." and ".." */
 576
 577                 namlen = strlen(e->d_name);
 578                 if ((len + namlen < PATH_MAX) &&
 579                     strcpy(path + len, e->d_name) &&
 580                     !lstat(path, &st) &&
 581                     S_ISDIR(st.st_mode) &&
 582                     !remove_empty_dir_recursive(path, len + namlen))
 583                         continue; /* happy */
 584
 585                 /* path too long, stat fails, or non-directory still exists */
 586                 ret = -1;
 587                 break;
 588         }
 589         closedir(dir);
 590         if (!ret) {
 591                 path[len] = 0;
 592                 ret = rmdir(path);
 593         }
 594         return ret;
 595 }
 596
 597 static int remove_empty_directories(char *file)
 598 {
 599         /* we want to create a file but there is a directory there;
 600          * if that is an empty directory (or a directory that contains
 601          * only empty directories), remove them.
 602          */
 603         char path[PATH_MAX];
 604         int len = strlen(file);
 605
 606         if (len >= PATH_MAX) /* path too long ;-) */
 607                 return -1;
 608         strcpy(path, file);
 609         return remove_empty_dir_recursive(path, len);
 610 }
 611
 612 static int is_refname_available(const char *ref, const char *oldref,
 613                                 struct ref_list *list, int quiet)
 614 {
 615         int namlen = strlen(ref); /* e.g. 'foo/bar' */
 616         while (list) {
 617                 /* list->name could be 'foo' or 'foo/bar/baz' */
 618                 if (!oldref || strcmp(oldref, list->name)) {
 619                         int len = strlen(list->name);
 620                         int cmplen = (namlen < len) ? namlen : len;
 621                         const char *lead = (namlen < len) ? list->name : ref;
 622                         if (!strncmp(ref, list->name, cmplen) &&
 623                             lead[cmplen] == '/') {
 624                                 if (!quiet)
 625                                         error("'%s' exists; cannot create '%s'",
 626                                               list->name, ref);
 627                                 return 0;
 628                         }
 629                 }
 630                 list = list->next;
 631         }
 632         return 1;
 633 }
 634
 635 static struct ref_lock *lock_ref_sha1_basic(const char *ref, const unsigned char *old_sha1, int *flag)
 636 {
 637         char *ref_file;
 638         const char *orig_ref = ref;
 639         struct ref_lock *lock;
 640         struct stat st;
 641         int last_errno = 0;
 642         int mustexist = (old_sha1 && !is_null_sha1(old_sha1));
 643
 644         lock = xcalloc(1, sizeof(struct ref_lock));
 645         lock->lock_fd = -1;
 646
 647         ref = resolve_ref(ref, lock->old_sha1, mustexist, flag);
 648         if (!ref && errno == EISDIR) {
 649                 /* we are trying to lock foo but we used to
 650                  * have foo/bar which now does not exist;
 651                  * it is normal for the empty directory 'foo'
 652                  * to remain.
 653                  */
 654                 ref_file = git_path("%s", orig_ref);
 655                 if (remove_empty_directories(ref_file)) {
 656                         last_errno = errno;
 657                         error("there are still refs under '%s'", orig_ref);
 658                         goto error_return;
 659                 }
 660                 ref = resolve_ref(orig_ref, lock->old_sha1, mustexist, flag);
 661         }
 662         if (!ref) {
 663                 last_errno = errno;
 664                 error("unable to resolve reference %s: %s",
 665                         orig_ref, strerror(errno));
 666                 goto error_return;
 667         }
 668         /* When the ref did not exist and we are creating it,
 669          * make sure there is no existing ref that is packed
 670          * whose name begins with our refname, nor a ref whose
 671          * name is a proper prefix of our refname.
 672          */
 673         if (is_null_sha1(lock->old_sha1) &&
 674             !is_refname_available(ref, NULL, get_packed_refs(), 0))
 675                 goto error_return;
 676
 677         lock->lk = xcalloc(1, sizeof(struct lock_file));
 678
 679         lock->ref_name = xstrdup(ref);
 680         lock->log_file = xstrdup(git_path("logs/%s", ref));
 681         ref_file = git_path("%s", ref);
 682         lock->force_write = lstat(ref_file, &st) && errno == ENOENT;
 683
 684         if (safe_create_leading_directories(ref_file)) {
 685                 last_errno = errno;
 686                 error("unable to create directory for %s", ref_file);
 687                 goto error_return;
 688         }
 689         lock->lock_fd = hold_lock_file_for_update(lock->lk, ref_file, 1);
 690
 691         return old_sha1 ? verify_lock(lock, old_sha1, mustexist) : lock;
 692
 693  error_return:
 694         unlock_ref(lock);
 695         errno = last_errno;
 696         return NULL;
 697 }
 698
 699 struct ref_lock *lock_ref_sha1(const char *ref, const unsigned char *old_sha1)
 700 {
 701         char refpath[PATH_MAX];
 702         if (check_ref_format(ref))
 703                 return NULL;
 704         strcpy(refpath, mkpath("refs/%s", ref));
 705         return lock_ref_sha1_basic(refpath, old_sha1, NULL);
 706 }
 707
 708 struct ref_lock *lock_any_ref_for_update(const char *ref, const unsigned char *old_sha1)
 709 {
 710         return lock_ref_sha1_basic(ref, old_sha1, NULL);
 711 }
 712
 713 static struct lock_file packlock;
 714
 715 static int repack_without_ref(const char *refname)
 716 {
 717         struct ref_list *list, *packed_ref_list;
 718         int fd;
 719         int found = 0;
 720
 721         packed_ref_list = get_packed_refs();
 722         for (list = packed_ref_list; list; list = list->next) {
 723                 if (!strcmp(refname, list->name)) {
 724                         found = 1;
 725                         break;
 726                 }
 727         }
 728         if (!found)
 729                 return 0;
 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
 750 int 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
 785 int 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 #ifdef __MINGW32__
 842                 if (errno == EEXIST) {
 843                         struct stat st;
 844                         if (stat(git_path("logs/%s", newref), &st) == 0 && S_ISDIR(st.st_mode))
 845                                 errno = EISDIR;
 846                         else
 847                                 errno = EEXIST;
 848                 }
 849 #endif
 850                 if (errno==EISDIR || errno==ENOTDIR) {
 851                         /*
 852                          * rename(a, b) when b is an existing
 853                          * directory ought to result in ISDIR, but
 854                          * Solaris 5.8 gives ENOTDIR.  Sheesh.
 855                          */
 856                         if (remove_empty_directories(git_path("logs/%s", newref))) {
 857                                 error("Directory not empty: logs/%s", newref);
 858                                 goto rollback;
 859                         }
 860                         goto retry;
 861                 } else {
 862                         error("unable to move logfile tmp-renamed-log to logs/%s: %s",
 863                                 newref, strerror(errno));
 864                         goto rollback;
 865                 }
 866         }
 867         logmoved = log;
 868
 869         lock = lock_ref_sha1_basic(newref, NULL, NULL);
 870         if (!lock) {
 871                 error("unable to lock %s for update", newref);
 872                 goto rollback;
 873         }
 874
 875         lock->force_write = 1;
 876         hashcpy(lock->old_sha1, orig_sha1);
 877         if (write_ref_sha1(lock, orig_sha1, logmsg)) {
 878                 error("unable to write current sha1 into %s", newref);
 879                 goto rollback;
 880         }
 881
 882         if (!strncmp(oldref, "refs/heads/", 11) &&
 883                         !strncmp(newref, "refs/heads/", 11)) {
 884                 char oldsection[1024], newsection[1024];
 885
 886                 snprintf(oldsection, 1024, "branch.%s", oldref + 11);
 887                 snprintf(newsection, 1024, "branch.%s", newref + 11);
 888                 if (git_config_rename_section(oldsection, newsection) < 0)
 889                         return 1;
 890         }
 891
 892         return 0;
 893
 894  rollback:
 895         lock = lock_ref_sha1_basic(oldref, NULL, NULL);
 896         if (!lock) {
 897                 error("unable to lock %s for rollback", oldref);
 898                 goto rollbacklog;
 899         }
 900
 901         lock->force_write = 1;
 902         flag = log_all_ref_updates;
 903         log_all_ref_updates = 0;
 904         if (write_ref_sha1(lock, orig_sha1, NULL))
 905                 error("unable to write current sha1 into %s", oldref);
 906         log_all_ref_updates = flag;
 907
 908  rollbacklog:
 909         if (logmoved && rename(git_path("logs/%s", newref), git_path("logs/%s", oldref)))
 910                 error("unable to restore logfile %s from %s: %s",
 911                         oldref, newref, strerror(errno));
 912         if (!logmoved && log &&
 913             rename(git_path("tmp-renamed-log"), git_path("logs/%s", oldref)))
 914                 error("unable to restore logfile %s from tmp-renamed-log: %s",
 915                         oldref, strerror(errno));
 916
 917         return 1;
 918 }
 919
 920 void unlock_ref(struct ref_lock *lock)
 921 {
 922         if (lock->lock_fd >= 0) {
 923                 close(lock->lock_fd);
 924                 /* Do not free lock->lk -- atexit() still looks at them */
 925                 if (lock->lk)
 926                         rollback_lock_file(lock->lk);
 927         }
 928         free(lock->ref_name);
 929         free(lock->log_file);
 930         free(lock);
 931 }
 932
 933 static int log_ref_write(struct ref_lock *lock,
 934         const unsigned char *sha1, const char *msg)
 935 {
 936         int logfd, written, oflags = O_APPEND | O_WRONLY;
 937         unsigned maxlen, len;
 938         char *logrec;
 939         const char *committer;
 940
 941         if (log_all_ref_updates < 0)
 942                 log_all_ref_updates = !is_bare_repository();
 943
 944         if (log_all_ref_updates &&
 945             (!strncmp(lock->ref_name, "refs/heads/", 11) ||
 946              !strncmp(lock->ref_name, "refs/remotes/", 13))) {
 947                 if (safe_create_leading_directories(lock->log_file) < 0)
 948                         return error("unable to create directory for %s",
 949                                 lock->log_file);
 950                 oflags |= O_CREAT;
 951         }
 952
 953         logfd = open(lock->log_file, oflags, 0666);
 954         if (logfd < 0) {
 955                 if (!(oflags & O_CREAT) && errno == ENOENT)
 956                         return 0;
 957
 958 #ifdef __MINGW32__
 959                 if ((oflags & O_CREAT) && errno == EACCES) {
 960                         struct stat st;
 961                         if (stat(lock->log_file, &st) == 0 && S_ISDIR(st.st_mode))
 962                                 errno = EISDIR;
 963                         else
 964                                 errno = EACCES;
 965                 }
 966 #endif
 967                 if ((oflags & O_CREAT) && errno == EISDIR) {
 968                         if (remove_empty_directories(lock->log_file)) {
 969                                 return error("There are still logs under '%s'",
 970                                              lock->log_file);
 971                         }
 972                         logfd = open(lock->log_file, oflags, 0666);
 973                 }
 974
 975                 if (logfd < 0)
 976                         return error("Unable to append to %s: %s",
 977                                      lock->log_file, strerror(errno));
 978         }
 979
 980         committer = git_committer_info(0);
 981         if (msg) {
 982                 maxlen = strlen(committer) + strlen(msg) + 2*40 + 5;
 983                 logrec = xmalloc(maxlen);
 984                 len = snprintf(logrec, maxlen, "%s %s %s\t%s\n",
 985                         sha1_to_hex(lock->old_sha1),
 986                         sha1_to_hex(sha1),
 987                         committer,
 988                         msg);
 989         }
 990         else {
 991                 maxlen = strlen(committer) + 2*40 + 4;
 992                 logrec = xmalloc(maxlen);
 993                 len = snprintf(logrec, maxlen, "%s %s %s\n",
 994                         sha1_to_hex(lock->old_sha1),
 995                         sha1_to_hex(sha1),
 996                         committer);
 997         }
 998         written = len <= maxlen ? write_in_full(logfd, logrec, len) : -1;
 999         free(logrec);
1000         close(logfd);
1001         if (written != len)
1002                 return error("Unable to append to %s", lock->log_file);
1003         return 0;
1004 }
1005
1006 int write_ref_sha1(struct ref_lock *lock,
1007         const unsigned char *sha1, const char *logmsg)
1008 {
1009         static char term = '\n';
1010
1011         if (!lock)
1012                 return -1;
1013         if (!lock->force_write && !hashcmp(lock->old_sha1, sha1)) {
1014                 unlock_ref(lock);
1015                 return 0;
1016         }
1017         if (write_in_full(lock->lock_fd, sha1_to_hex(sha1), 40) != 40 ||
1018             write_in_full(lock->lock_fd, &term, 1) != 1
1019                 || close(lock->lock_fd) < 0) {
1020                 error("Couldn't write %s", lock->lk->filename);
1021                 unlock_ref(lock);
1022                 return -1;
1023         }
1024         invalidate_cached_refs();
1025         if (log_ref_write(lock, sha1, logmsg) < 0) {
1026                 unlock_ref(lock);
1027                 return -1;
1028         }
1029         if (commit_lock_file(lock->lk)) {
1030                 error("Couldn't set %s", lock->ref_name);
1031                 unlock_ref(lock);
1032                 return -1;
1033         }
1034         lock->lock_fd = -1;
1035         unlock_ref(lock);
1036         return 0;
1037 }
1038
1039 int read_ref_at(const char *ref, unsigned long at_time, int cnt, unsigned char *sha1)
1040 {
1041         const char *logfile, *logdata, *logend, *rec, *lastgt, *lastrec;
1042         char *tz_c;
1043         int logfd, tz, reccnt = 0;
1044         struct stat st;
1045         unsigned long date;
1046         unsigned char logged_sha1[20];
1047
1048         logfile = git_path("logs/%s", ref);
1049         logfd = open(logfile, O_RDONLY, 0);
1050         if (logfd < 0)
1051                 die("Unable to read log %s: %s", logfile, strerror(errno));
1052         fstat(logfd, &st);
1053         if (!st.st_size)
1054                 die("Log %s is empty.", logfile);
1055         logdata = xmmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, logfd, 0);
1056         close(logfd);
1057
1058         lastrec = NULL;
1059         rec = logend = logdata + st.st_size;
1060         while (logdata < rec) {
1061                 reccnt++;
1062                 if (logdata < rec && *(rec-1) == '\n')
1063                         rec--;
1064                 lastgt = NULL;
1065                 while (logdata < rec && *(rec-1) != '\n') {
1066                         rec--;
1067                         if (*rec == '>')
1068                                 lastgt = rec;
1069                 }
1070                 if (!lastgt)
1071                         die("Log %s is corrupt.", logfile);
1072                 date = strtoul(lastgt + 1, &tz_c, 10);
1073                 if (date <= at_time || cnt == 0) {
1074                         if (lastrec) {
1075                                 if (get_sha1_hex(lastrec, logged_sha1))
1076                                         die("Log %s is corrupt.", logfile);
1077                                 if (get_sha1_hex(rec + 41, sha1))
1078                                         die("Log %s is corrupt.", logfile);
1079                                 if (hashcmp(logged_sha1, sha1)) {
1080                                         tz = strtoul(tz_c, NULL, 10);
1081                                         fprintf(stderr,
1082                                                 "warning: Log %s has gap after %s.\n",
1083                                                 logfile, show_rfc2822_date(date, tz));
1084                                 }
1085                         }
1086                         else if (date == at_time) {
1087                                 if (get_sha1_hex(rec + 41, sha1))
1088                                         die("Log %s is corrupt.", logfile);
1089                         }
1090                         else {
1091                                 if (get_sha1_hex(rec + 41, logged_sha1))
1092                                         die("Log %s is corrupt.", logfile);
1093                                 if (hashcmp(logged_sha1, sha1)) {
1094                                         tz = strtoul(tz_c, NULL, 10);
1095                                         fprintf(stderr,
1096                                                 "warning: Log %s unexpectedly ended on %s.\n",
1097                                                 logfile, show_rfc2822_date(date, tz));
1098                                 }
1099                         }
1100                         munmap((void*)logdata, st.st_size);
1101                         return 0;
1102                 }
1103                 lastrec = rec;
1104                 if (cnt > 0)
1105                         cnt--;
1106         }
1107
1108         rec = logdata;
1109         while (rec < logend && *rec != '>' && *rec != '\n')
1110                 rec++;
1111         if (rec == logend || *rec == '\n')
1112                 die("Log %s is corrupt.", logfile);
1113         date = strtoul(rec + 1, &tz_c, 10);
1114         tz = strtoul(tz_c, NULL, 10);
1115         if (get_sha1_hex(logdata, sha1))
1116                 die("Log %s is corrupt.", logfile);
1117         munmap((void*)logdata, st.st_size);
1118         if (at_time)
1119                 fprintf(stderr, "warning: Log %s only goes back to %s.\n",
1120                         logfile, show_rfc2822_date(date, tz));
1121         else
1122                 fprintf(stderr, "warning: Log %s only has %d entries.\n",
1123                         logfile, reccnt);
1124         return 0;
1125 }
1126
1127 int for_each_reflog_ent(const char *ref, each_reflog_ent_fn fn, void *cb_data)
1128 {
1129         const char *logfile;
1130         FILE *logfp;
1131         char buf[1024];
1132
1133         logfile = git_path("logs/%s", ref);
1134         logfp = fopen(logfile, "r");
1135         if (!logfp)
1136                 return -1;
1137         while (fgets(buf, sizeof(buf), logfp)) {
1138                 unsigned char osha1[20], nsha1[20];
1139                 char *email_end, *message;
1140                 unsigned long timestamp;
1141                 int len, ret, tz;
1142
1143                 /* old SP new SP name <email> SP time TAB msg LF */
1144                 len = strlen(buf);
1145                 if (len < 83 || buf[len-1] != '\n' ||
1146                     get_sha1_hex(buf, osha1) || buf[40] != ' ' ||
1147                     get_sha1_hex(buf + 41, nsha1) || buf[81] != ' ' ||
1148                     !(email_end = strchr(buf + 82, '>')) ||
1149                     email_end[1] != ' ' ||
1150                     !(timestamp = strtoul(email_end + 2, &message, 10)) ||
1151                     !message || message[0] != ' ' ||
1152                     (message[1] != '+' && message[1] != '-') ||
1153                     !isdigit(message[2]) || !isdigit(message[3]) ||
1154                     !isdigit(message[4]) || !isdigit(message[5]) ||
1155                     message[6] != '\t')
1156                         continue; /* corrupt? */
1157                 email_end[1] = '\0';
1158                 tz = strtol(message + 1, NULL, 10);
1159                 message += 7;
1160                 ret = fn(osha1, nsha1, buf+82, timestamp, tz, message, cb_data);
1161                 if (ret)
1162                         return ret;
1163         }
1164         fclose(logfp);
1165         return 0;
1166 }
1167