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 read_ref(const char *ref, unsigned char *sha1)
 313 {
 314         if (resolve_ref(ref, sha1, 1, NULL))
 315                 return 0;
 316         return -1;
 317 }
 318
 319 static int do_one_ref(const char *base, each_ref_fn fn, int trim,
 320                       void *cb_data, struct ref_list *entry)
 321 {
 322         if (strncmp(base, entry->name, trim))
 323                 return 0;
 324         if (is_null_sha1(entry->sha1))
 325                 return 0;
 326         if (!has_sha1_file(entry->sha1)) {
 327                 error("%s does not point to a valid object!", entry->name);
 328                 return 0;
 329         }
 330         return fn(entry->name + trim, entry->sha1, entry->flag, cb_data);
 331 }
 332
 333 int peel_ref(const char *ref, unsigned char *sha1)
 334 {
 335         int flag;
 336         unsigned char base[20];
 337         struct object *o;
 338
 339         if (!resolve_ref(ref, base, 1, &flag))
 340                 return -1;
 341
 342         if ((flag & REF_ISPACKED)) {
 343                 struct ref_list *list = get_packed_refs();
 344
 345                 while (list) {
 346                         if (!strcmp(list->name, ref)) {
 347                                 if (list->flag & REF_KNOWS_PEELED) {
 348                                         hashcpy(sha1, list->peeled);
 349                                         return 0;
 350                                 }
 351                                 /* older pack-refs did not leave peeled ones */
 352                                 break;
 353                         }
 354                         list = list->next;
 355                 }
 356         }
 357
 358         /* fallback - callers should not call this for unpacked refs */
 359         o = parse_object(base);
 360         if (o->type == OBJ_TAG) {
 361                 o = deref_tag(o, ref, 0);
 362                 if (o) {
 363                         hashcpy(sha1, o->sha1);
 364                         return 0;
 365                 }
 366         }
 367         return -1;
 368 }
 369
 370 static int do_for_each_ref(const char *base, each_ref_fn fn, int trim,
 371                            void *cb_data)
 372 {
 373         int retval;
 374         struct ref_list *packed = get_packed_refs();
 375         struct ref_list *loose = get_loose_refs();
 376
 377         while (packed && loose) {
 378                 struct ref_list *entry;
 379                 int cmp = strcmp(packed->name, loose->name);
 380                 if (!cmp) {
 381                         packed = packed->next;
 382                         continue;
 383                 }
 384                 if (cmp > 0) {
 385                         entry = loose;
 386                         loose = loose->next;
 387                 } else {
 388                         entry = packed;
 389                         packed = packed->next;
 390                 }
 391                 retval = do_one_ref(base, fn, trim, cb_data, entry);
 392                 if (retval)
 393                         return retval;
 394         }
 395
 396         for (packed = packed ? packed : loose; packed; packed = packed->next) {
 397                 retval = do_one_ref(base, fn, trim, cb_data, packed);
 398                 if (retval)
 399                         return retval;
 400         }
 401         return 0;
 402 }
 403
 404 int head_ref(each_ref_fn fn, void *cb_data)
 405 {
 406         unsigned char sha1[20];
 407         int flag;
 408
 409         if (resolve_ref("HEAD", sha1, 1, &flag))
 410                 return fn("HEAD", sha1, flag, cb_data);
 411         return 0;
 412 }
 413
 414 int for_each_ref(each_ref_fn fn, void *cb_data)
 415 {
 416         return do_for_each_ref("refs/", fn, 0, cb_data);
 417 }
 418
 419 int for_each_tag_ref(each_ref_fn fn, void *cb_data)
 420 {
 421         return do_for_each_ref("refs/tags/", fn, 10, cb_data);
 422 }
 423
 424 int for_each_branch_ref(each_ref_fn fn, void *cb_data)
 425 {
 426         return do_for_each_ref("refs/heads/", fn, 11, cb_data);
 427 }
 428
 429 int for_each_remote_ref(each_ref_fn fn, void *cb_data)
 430 {
 431         return do_for_each_ref("refs/remotes/", fn, 13, cb_data);
 432 }
 433
 434 /* NEEDSWORK: This is only used by ssh-upload and it should go; the
 435  * caller should do resolve_ref or read_ref like everybody else.  Or
 436  * maybe everybody else should use get_ref_sha1() instead of doing
 437  * read_ref().
 438  */
 439 int get_ref_sha1(const char *ref, unsigned char *sha1)
 440 {
 441         if (check_ref_format(ref))
 442                 return -1;
 443         return read_ref(mkpath("refs/%s", ref), sha1);
 444 }
 445
 446 /*
 447  * Make sure "ref" is something reasonable to have under ".git/refs/";
 448  * We do not like it if:
 449  *
 450  * - any path component of it begins with ".", or
 451  * - it has double dots "..", or
 452  * - it has ASCII control character, "~", "^", ":" or SP, anywhere, or
 453  * - it ends with a "/".
 454  */
 455
 456 static inline int bad_ref_char(int ch)
 457 {
 458         return (((unsigned) ch) <= ' ' ||
 459                 ch == '~' || ch == '^' || ch == ':' ||
 460                 /* 2.13 Pattern Matching Notation */
 461                 ch == '?' || ch == '*' || ch == '[');
 462 }
 463
 464 int check_ref_format(const char *ref)
 465 {
 466         int ch, level;
 467         const char *cp = ref;
 468
 469         level = 0;
 470         while (1) {
 471                 while ((ch = *cp++) == '/')
 472                         ; /* tolerate duplicated slashes */
 473                 if (!ch)
 474                         return -1; /* should not end with slashes */
 475
 476                 /* we are at the beginning of the path component */
 477                 if (ch == '.' || bad_ref_char(ch))
 478                         return -1;
 479
 480                 /* scan the rest of the path component */
 481                 while ((ch = *cp++) != 0) {
 482                         if (bad_ref_char(ch))
 483                                 return -1;
 484                         if (ch == '/')
 485                                 break;
 486                         if (ch == '.' && *cp == '.')
 487                                 return -1;
 488                 }
 489                 level++;
 490                 if (!ch) {
 491                         if (level < 2)
 492                                 return -2; /* at least of form "heads/blah" */
 493                         return 0;
 494                 }
 495         }
 496 }
 497
 498 static struct ref_lock *verify_lock(struct ref_lock *lock,
 499         const unsigned char *old_sha1, int mustexist)
 500 {
 501         if (!resolve_ref(lock->ref_name, lock->old_sha1, mustexist, NULL)) {
 502                 error("Can't verify ref %s", lock->ref_name);
 503                 unlock_ref(lock);
 504                 return NULL;
 505         }
 506         if (hashcmp(lock->old_sha1, old_sha1)) {
 507                 error("Ref %s is at %s but expected %s", lock->ref_name,
 508                         sha1_to_hex(lock->old_sha1), sha1_to_hex(old_sha1));
 509                 unlock_ref(lock);
 510                 return NULL;
 511         }
 512         return lock;
 513 }
 514
 515 static int remove_empty_dir_recursive(char *path, int len)
 516 {
 517         DIR *dir = opendir(path);
 518         struct dirent *e;
 519         int ret = 0;
 520
 521         if (!dir)
 522                 return -1;
 523         if (path[len-1] != '/')
 524                 path[len++] = '/';
 525         while ((e = readdir(dir)) != NULL) {
 526                 struct stat st;
 527                 int namlen;
 528                 if ((e->d_name[0] == '.') &&
 529                     ((e->d_name[1] == 0) ||
 530                      ((e->d_name[1] == '.') && e->d_name[2] == 0)))
 531                         continue; /* "." and ".." */
 532
 533                 namlen = strlen(e->d_name);
 534                 if ((len + namlen < PATH_MAX) &&
 535                     strcpy(path + len, e->d_name) &&
 536                     !lstat(path, &st) &&
 537                     S_ISDIR(st.st_mode) &&
 538                     !remove_empty_dir_recursive(path, len + namlen))
 539                         continue; /* happy */
 540
 541                 /* path too long, stat fails, or non-directory still exists */
 542                 ret = -1;
 543                 break;
 544         }
 545         closedir(dir);
 546         if (!ret) {
 547                 path[len] = 0;
 548                 ret = rmdir(path);
 549         }
 550         return ret;
 551 }
 552
 553 static int remove_empty_directories(char *file)
 554 {
 555         /* we want to create a file but there is a directory there;
 556          * if that is an empty directory (or a directory that contains
 557          * only empty directories), remove them.
 558          */
 559         char path[PATH_MAX];
 560         int len = strlen(file);
 561
 562         if (len >= PATH_MAX) /* path too long ;-) */
 563                 return -1;
 564         strcpy(path, file);
 565         return remove_empty_dir_recursive(path, len);
 566 }
 567
 568 static int is_refname_available(const char *ref, const char *oldref,
 569                                 struct ref_list *list, int quiet)
 570 {
 571         int namlen = strlen(ref); /* e.g. 'foo/bar' */
 572         while (list) {
 573                 /* list->name could be 'foo' or 'foo/bar/baz' */
 574                 if (!oldref || strcmp(oldref, list->name)) {
 575                         int len = strlen(list->name);
 576                         int cmplen = (namlen < len) ? namlen : len;
 577                         const char *lead = (namlen < len) ? list->name : ref;
 578                         if (!strncmp(ref, list->name, cmplen) &&
 579                             lead[cmplen] == '/') {
 580                                 if (!quiet)
 581                                         error("'%s' exists; cannot create '%s'",
 582                                               list->name, ref);
 583                                 return 0;
 584                         }
 585                 }
 586                 list = list->next;
 587         }
 588         return 1;
 589 }
 590
 591 static struct ref_lock *lock_ref_sha1_basic(const char *ref, const unsigned char *old_sha1, int *flag)
 592 {
 593         char *ref_file;
 594         const char *orig_ref = ref;
 595         struct ref_lock *lock;
 596         struct stat st;
 597         int last_errno = 0;
 598         int mustexist = (old_sha1 && !is_null_sha1(old_sha1));
 599
 600         lock = xcalloc(1, sizeof(struct ref_lock));
 601         lock->lock_fd = -1;
 602
 603         ref = resolve_ref(ref, lock->old_sha1, mustexist, flag);
 604         if (!ref && errno == EISDIR) {
 605                 /* we are trying to lock foo but we used to
 606                  * have foo/bar which now does not exist;
 607                  * it is normal for the empty directory 'foo'
 608                  * to remain.
 609                  */
 610                 ref_file = git_path("%s", orig_ref);
 611                 if (remove_empty_directories(ref_file)) {
 612                         last_errno = errno;
 613                         error("there are still refs under '%s'", orig_ref);
 614                         goto error_return;
 615                 }
 616                 ref = resolve_ref(orig_ref, lock->old_sha1, mustexist, flag);
 617         }
 618         if (!ref) {
 619                 last_errno = errno;
 620                 error("unable to resolve reference %s: %s",
 621                         orig_ref, strerror(errno));
 622                 goto error_return;
 623         }
 624         /* When the ref did not exist and we are creating it,
 625          * make sure there is no existing ref that is packed
 626          * whose name begins with our refname, nor a ref whose
 627          * name is a proper prefix of our refname.
 628          */
 629         if (is_null_sha1(lock->old_sha1) &&
 630             !is_refname_available(ref, NULL, get_packed_refs(), 0))
 631                 goto error_return;
 632
 633         lock->lk = xcalloc(1, sizeof(struct lock_file));
 634
 635         lock->ref_name = xstrdup(ref);
 636         lock->orig_ref_name = xstrdup(orig_ref);
 637         ref_file = git_path("%s", ref);
 638         lock->force_write = lstat(ref_file, &st) && errno == ENOENT;
 639
 640         if (safe_create_leading_directories(ref_file)) {
 641                 last_errno = errno;
 642                 error("unable to create directory for %s", ref_file);
 643                 goto error_return;
 644         }
 645         lock->lock_fd = hold_lock_file_for_update(lock->lk, ref_file, 1);
 646
 647         return old_sha1 ? verify_lock(lock, old_sha1, mustexist) : lock;
 648
 649  error_return:
 650         unlock_ref(lock);
 651         errno = last_errno;
 652         return NULL;
 653 }
 654
 655 struct ref_lock *lock_ref_sha1(const char *ref, const unsigned char *old_sha1)
 656 {
 657         char refpath[PATH_MAX];
 658         if (check_ref_format(ref))
 659                 return NULL;
 660         strcpy(refpath, mkpath("refs/%s", ref));
 661         return lock_ref_sha1_basic(refpath, old_sha1, NULL);
 662 }
 663
 664 struct ref_lock *lock_any_ref_for_update(const char *ref, const unsigned char *old_sha1)
 665 {
 666         return lock_ref_sha1_basic(ref, old_sha1, NULL);
 667 }
 668
 669 static struct lock_file packlock;
 670
 671 static int repack_without_ref(const char *refname)
 672 {
 673         struct ref_list *list, *packed_ref_list;
 674         int fd;
 675         int found = 0;
 676
 677         packed_ref_list = get_packed_refs();
 678         for (list = packed_ref_list; list; list = list->next) {
 679                 if (!strcmp(refname, list->name)) {
 680                         found = 1;
 681                         break;
 682                 }
 683         }
 684         if (!found)
 685                 return 0;
 686         fd = hold_lock_file_for_update(&packlock, git_path("packed-refs"), 0);
 687         if (fd < 0)
 688                 return error("cannot delete '%s' from packed refs", refname);
 689
 690         for (list = packed_ref_list; list; list = list->next) {
 691                 char line[PATH_MAX + 100];
 692                 int len;
 693
 694                 if (!strcmp(refname, list->name))
 695                         continue;
 696                 len = snprintf(line, sizeof(line), "%s %s\n",
 697                                sha1_to_hex(list->sha1), list->name);
 698                 /* this should not happen but just being defensive */
 699                 if (len > sizeof(line))
 700                         die("too long a refname '%s'", list->name);
 701                 write_or_die(fd, line, len);
 702         }
 703         return commit_lock_file(&packlock);
 704 }
 705
 706 int delete_ref(const char *refname, unsigned char *sha1)
 707 {
 708         struct ref_lock *lock;
 709         int err, i, ret = 0, flag = 0;
 710
 711         lock = lock_ref_sha1_basic(refname, sha1, &flag);
 712         if (!lock)
 713                 return 1;
 714         if (!(flag & REF_ISPACKED)) {
 715                 /* loose */
 716                 i = strlen(lock->lk->filename) - 5; /* .lock */
 717                 lock->lk->filename[i] = 0;
 718                 err = unlink(lock->lk->filename);
 719                 if (err) {
 720                         ret = 1;
 721                         error("unlink(%s) failed: %s",
 722                               lock->lk->filename, strerror(errno));
 723                 }
 724                 lock->lk->filename[i] = '.';
 725         }
 726         /* removing the loose one could have resurrected an earlier
 727          * packed one.  Also, if it was not loose we need to repack
 728          * without it.
 729          */
 730         ret |= repack_without_ref(refname);
 731
 732         err = unlink(git_path("logs/%s", lock->ref_name));
 733         if (err && errno != ENOENT)
 734                 fprintf(stderr, "warning: unlink(%s) failed: %s",
 735                         git_path("logs/%s", lock->ref_name), strerror(errno));
 736         invalidate_cached_refs();
 737         unlock_ref(lock);
 738         return ret;
 739 }
 740
 741 int rename_ref(const char *oldref, const char *newref, const char *logmsg)
 742 {
 743         static const char renamed_ref[] = "RENAMED-REF";
 744         unsigned char sha1[20], orig_sha1[20];
 745         int flag = 0, logmoved = 0;
 746         struct ref_lock *lock;
 747         struct stat loginfo;
 748         int log = !lstat(git_path("logs/%s", oldref), &loginfo);
 749
 750         if (S_ISLNK(loginfo.st_mode))
 751                 return error("reflog for %s is a symlink", oldref);
 752
 753         if (!resolve_ref(oldref, orig_sha1, 1, &flag))
 754                 return error("refname %s not found", oldref);
 755
 756         if (!is_refname_available(newref, oldref, get_packed_refs(), 0))
 757                 return 1;
 758
 759         if (!is_refname_available(newref, oldref, get_loose_refs(), 0))
 760                 return 1;
 761
 762         lock = lock_ref_sha1_basic(renamed_ref, NULL, NULL);
 763         if (!lock)
 764                 return error("unable to lock %s", renamed_ref);
 765         lock->force_write = 1;
 766         if (write_ref_sha1(lock, orig_sha1, logmsg))
 767                 return error("unable to save current sha1 in %s", renamed_ref);
 768
 769         if (log && rename(git_path("logs/%s", oldref), git_path("tmp-renamed-log")))
 770                 return error("unable to move logfile logs/%s to tmp-renamed-log: %s",
 771                         oldref, strerror(errno));
 772
 773         if (delete_ref(oldref, orig_sha1)) {
 774                 error("unable to delete old %s", oldref);
 775                 goto rollback;
 776         }
 777
 778         if (resolve_ref(newref, sha1, 1, &flag) && delete_ref(newref, sha1)) {
 779                 if (errno==EISDIR) {
 780                         if (remove_empty_directories(git_path("%s", newref))) {
 781                                 error("Directory not empty: %s", newref);
 782                                 goto rollback;
 783                         }
 784                 } else {
 785                         error("unable to delete existing %s", newref);
 786                         goto rollback;
 787                 }
 788         }
 789
 790         if (log && safe_create_leading_directories(git_path("logs/%s", newref))) {
 791                 error("unable to create directory for %s", newref);
 792                 goto rollback;
 793         }
 794
 795  retry:
 796         if (log && rename(git_path("tmp-renamed-log"), git_path("logs/%s", newref))) {
 797                 if (errno==EISDIR || errno==ENOTDIR) {
 798                         /*
 799                          * rename(a, b) when b is an existing
 800                          * directory ought to result in ISDIR, but
 801                          * Solaris 5.8 gives ENOTDIR.  Sheesh.
 802                          */
 803                         if (remove_empty_directories(git_path("logs/%s", newref))) {
 804                                 error("Directory not empty: logs/%s", newref);
 805                                 goto rollback;
 806                         }
 807                         goto retry;
 808                 } else {
 809                         error("unable to move logfile tmp-renamed-log to logs/%s: %s",
 810                                 newref, strerror(errno));
 811                         goto rollback;
 812                 }
 813         }
 814         logmoved = log;
 815
 816         lock = lock_ref_sha1_basic(newref, NULL, NULL);
 817         if (!lock) {
 818                 error("unable to lock %s for update", newref);
 819                 goto rollback;
 820         }
 821
 822         lock->force_write = 1;
 823         hashcpy(lock->old_sha1, orig_sha1);
 824         if (write_ref_sha1(lock, orig_sha1, logmsg)) {
 825                 error("unable to write current sha1 into %s", newref);
 826                 goto rollback;
 827         }
 828
 829         if (!strncmp(oldref, "refs/heads/", 11) &&
 830                         !strncmp(newref, "refs/heads/", 11)) {
 831                 char oldsection[1024], newsection[1024];
 832
 833                 snprintf(oldsection, 1024, "branch.%s", oldref + 11);
 834                 snprintf(newsection, 1024, "branch.%s", newref + 11);
 835                 if (git_config_rename_section(oldsection, newsection) < 0)
 836                         return 1;
 837         }
 838
 839         return 0;
 840
 841  rollback:
 842         lock = lock_ref_sha1_basic(oldref, NULL, NULL);
 843         if (!lock) {
 844                 error("unable to lock %s for rollback", oldref);
 845                 goto rollbacklog;
 846         }
 847
 848         lock->force_write = 1;
 849         flag = log_all_ref_updates;
 850         log_all_ref_updates = 0;
 851         if (write_ref_sha1(lock, orig_sha1, NULL))
 852                 error("unable to write current sha1 into %s", oldref);
 853         log_all_ref_updates = flag;
 854
 855  rollbacklog:
 856         if (logmoved && rename(git_path("logs/%s", newref), git_path("logs/%s", oldref)))
 857                 error("unable to restore logfile %s from %s: %s",
 858                         oldref, newref, strerror(errno));
 859         if (!logmoved && log &&
 860             rename(git_path("tmp-renamed-log"), git_path("logs/%s", oldref)))
 861                 error("unable to restore logfile %s from tmp-renamed-log: %s",
 862                         oldref, strerror(errno));
 863
 864         return 1;
 865 }
 866
 867 void unlock_ref(struct ref_lock *lock)
 868 {
 869         if (lock->lock_fd >= 0) {
 870                 close(lock->lock_fd);
 871                 /* Do not free lock->lk -- atexit() still looks at them */
 872                 if (lock->lk)
 873                         rollback_lock_file(lock->lk);
 874         }
 875         free(lock->ref_name);
 876         free(lock->orig_ref_name);
 877         free(lock);
 878 }
 879
 880 static int log_ref_write(const char *ref_name, const unsigned char *old_sha1,
 881                          const unsigned char *new_sha1, const char *msg)
 882 {
 883         int logfd, written, oflags = O_APPEND | O_WRONLY;
 884         unsigned maxlen, len;
 885         int msglen;
 886         char *log_file, *logrec;
 887         const char *committer;
 888
 889         if (log_all_ref_updates < 0)
 890                 log_all_ref_updates = !is_bare_repository();
 891
 892         log_file = git_path("logs/%s", ref_name);
 893
 894         if (log_all_ref_updates &&
 895             (!strncmp(ref_name, "refs/heads/", 11) ||
 896              !strncmp(ref_name, "refs/remotes/", 13) ||
 897              !strcmp(ref_name, "HEAD"))) {
 898                 if (safe_create_leading_directories(log_file) < 0)
 899                         return error("unable to create directory for %s",
 900                                      log_file);
 901                 oflags |= O_CREAT;
 902         }
 903
 904         logfd = open(log_file, oflags, 0666);
 905         if (logfd < 0) {
 906                 if (!(oflags & O_CREAT) && errno == ENOENT)
 907                         return 0;
 908
 909                 if ((oflags & O_CREAT) && errno == EISDIR) {
 910                         if (remove_empty_directories(log_file)) {
 911                                 return error("There are still logs under '%s'",
 912                                              log_file);
 913                         }
 914                         logfd = open(log_file, oflags, 0666);
 915                 }
 916
 917                 if (logfd < 0)
 918                         return error("Unable to append to %s: %s",
 919                                      log_file, strerror(errno));
 920         }
 921
 922         msglen = 0;
 923         if (msg) {
 924                 /* clean up the message and make sure it is a single line */
 925                 for ( ; *msg; msg++)
 926                         if (!isspace(*msg))
 927                                 break;
 928                 if (*msg) {
 929                         const char *ep = strchr(msg, '\n');
 930                         if (ep)
 931                                 msglen = ep - msg;
 932                         else
 933                                 msglen = strlen(msg);
 934                 }
 935         }
 936
 937         committer = git_committer_info(-1);
 938         maxlen = strlen(committer) + msglen + 100;
 939         logrec = xmalloc(maxlen);
 940         len = sprintf(logrec, "%s %s %s\n",
 941                       sha1_to_hex(old_sha1),
 942                       sha1_to_hex(new_sha1),
 943                       committer);
 944         if (msglen)
 945                 len += sprintf(logrec + len - 1, "\t%.*s\n", msglen, msg) - 1;
 946         written = len <= maxlen ? write_in_full(logfd, logrec, len) : -1;
 947         free(logrec);
 948         close(logfd);
 949         if (written != len)
 950                 return error("Unable to append to %s", log_file);
 951         return 0;
 952 }
 953
 954 int write_ref_sha1(struct ref_lock *lock,
 955         const unsigned char *sha1, const char *logmsg)
 956 {
 957         static char term = '\n';
 958
 959         if (!lock)
 960                 return -1;
 961         if (!lock->force_write && !hashcmp(lock->old_sha1, sha1)) {
 962                 unlock_ref(lock);
 963                 return 0;
 964         }
 965         if (write_in_full(lock->lock_fd, sha1_to_hex(sha1), 40) != 40 ||
 966             write_in_full(lock->lock_fd, &term, 1) != 1
 967                 || close(lock->lock_fd) < 0) {
 968                 error("Couldn't write %s", lock->lk->filename);
 969                 unlock_ref(lock);
 970                 return -1;
 971         }
 972         invalidate_cached_refs();
 973         if (log_ref_write(lock->ref_name, lock->old_sha1, sha1, logmsg) < 0 ||
 974             (strcmp(lock->ref_name, lock->orig_ref_name) &&
 975              log_ref_write(lock->orig_ref_name, lock->old_sha1, sha1, logmsg) < 0)) {
 976                 unlock_ref(lock);
 977                 return -1;
 978         }
 979         if (commit_lock_file(lock->lk)) {
 980                 error("Couldn't set %s", lock->ref_name);
 981                 unlock_ref(lock);
 982                 return -1;
 983         }
 984         lock->lock_fd = -1;
 985         unlock_ref(lock);
 986         return 0;
 987 }
 988
 989 int create_symref(const char *ref_target, const char *refs_heads_master,
 990                   const char *logmsg)
 991 {
 992         const char *lockpath;
 993         char ref[1000];
 994         int fd, len, written;
 995         char *git_HEAD = xstrdup(git_path("%s", ref_target));
 996         unsigned char old_sha1[20], new_sha1[20];
 997
 998         if (logmsg && read_ref(ref_target, old_sha1))
 999                 hashclr(old_sha1);
1000
1001 #ifndef NO_SYMLINK_HEAD
1002         if (prefer_symlink_refs) {
1003                 unlink(git_HEAD);
1004                 if (!symlink(refs_heads_master, git_HEAD))
1005                         goto done;
1006                 fprintf(stderr, "no symlink - falling back to symbolic ref\n");
1007         }
1008 #endif
1009
1010         len = snprintf(ref, sizeof(ref), "ref: %s\n", refs_heads_master);
1011         if (sizeof(ref) <= len) {
1012                 error("refname too long: %s", refs_heads_master);
1013                 goto error_free_return;
1014         }
1015         lockpath = mkpath("%s.lock", git_HEAD);
1016         fd = open(lockpath, O_CREAT | O_EXCL | O_WRONLY, 0666);
1017         if (fd < 0) {
1018                 error("Unable to open %s for writing", lockpath);
1019                 goto error_free_return;
1020         }
1021         written = write_in_full(fd, ref, len);
1022         close(fd);
1023         if (written != len) {
1024                 error("Unable to write to %s", lockpath);
1025                 goto error_unlink_return;
1026         }
1027         if (rename(lockpath, git_HEAD) < 0) {
1028                 error("Unable to create %s", git_HEAD);
1029                 goto error_unlink_return;
1030         }
1031         if (adjust_shared_perm(git_HEAD)) {
1032                 error("Unable to fix permissions on %s", lockpath);
1033         error_unlink_return:
1034                 unlink(lockpath);
1035         error_free_return:
1036                 free(git_HEAD);
1037                 return -1;
1038         }
1039
1040         done:
1041         if (logmsg && !read_ref(refs_heads_master, new_sha1))
1042                 log_ref_write(ref_target, old_sha1, new_sha1, logmsg);
1043
1044         free(git_HEAD);
1045         return 0;
1046 }
1047
1048 static char *ref_msg(const char *line, const char *endp)
1049 {
1050         const char *ep;
1051         char *msg;
1052
1053         line += 82;
1054         for (ep = line; ep < endp && *ep != '\n'; ep++)
1055                 ;
1056         msg = xmalloc(ep - line + 1);
1057         memcpy(msg, line, ep - line);
1058         msg[ep - line] = 0;
1059         return msg;
1060 }
1061
1062 int read_ref_at(const char *ref, unsigned long at_time, int cnt, unsigned char *sha1, char **msg, unsigned long *cutoff_time, int *cutoff_tz, int *cutoff_cnt)
1063 {
1064         const char *logfile, *logdata, *logend, *rec, *lastgt, *lastrec;
1065         char *tz_c;
1066         int logfd, tz, reccnt = 0;
1067         struct stat st;
1068         unsigned long date;
1069         unsigned char logged_sha1[20];
1070         void *log_mapped;
1071
1072         logfile = git_path("logs/%s", ref);
1073         logfd = open(logfile, O_RDONLY, 0);
1074         if (logfd < 0)
1075                 die("Unable to read log %s: %s", logfile, strerror(errno));
1076         fstat(logfd, &st);
1077         if (!st.st_size)
1078                 die("Log %s is empty.", logfile);
1079         log_mapped = xmmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, logfd, 0);
1080         logdata = log_mapped;
1081         close(logfd);
1082
1083         lastrec = NULL;
1084         rec = logend = logdata + st.st_size;
1085         while (logdata < rec) {
1086                 reccnt++;
1087                 if (logdata < rec && *(rec-1) == '\n')
1088                         rec--;
1089                 lastgt = NULL;
1090                 while (logdata < rec && *(rec-1) != '\n') {
1091                         rec--;
1092                         if (*rec == '>')
1093                                 lastgt = rec;
1094                 }
1095                 if (!lastgt)
1096                         die("Log %s is corrupt.", logfile);
1097                 date = strtoul(lastgt + 1, &tz_c, 10);
1098                 if (date <= at_time || cnt == 0) {
1099                         tz = strtoul(tz_c, NULL, 10);
1100                         if (msg)
1101                                 *msg = ref_msg(rec, logend);
1102                         if (cutoff_time)
1103                                 *cutoff_time = date;
1104                         if (cutoff_tz)
1105                                 *cutoff_tz = tz;
1106                         if (cutoff_cnt)
1107                                 *cutoff_cnt = reccnt - 1;
1108                         if (lastrec) {
1109                                 if (get_sha1_hex(lastrec, logged_sha1))
1110                                         die("Log %s is corrupt.", logfile);
1111                                 if (get_sha1_hex(rec + 41, sha1))
1112                                         die("Log %s is corrupt.", logfile);
1113                                 if (hashcmp(logged_sha1, sha1)) {
1114                                         fprintf(stderr,
1115                                                 "warning: Log %s has gap after %s.\n",
1116                                                 logfile, show_rfc2822_date(date, tz));
1117                                 }
1118                         }
1119                         else if (date == at_time) {
1120                                 if (get_sha1_hex(rec + 41, sha1))
1121                                         die("Log %s is corrupt.", logfile);
1122                         }
1123                         else {
1124                                 if (get_sha1_hex(rec + 41, logged_sha1))
1125                                         die("Log %s is corrupt.", logfile);
1126                                 if (hashcmp(logged_sha1, sha1)) {
1127                                         fprintf(stderr,
1128                                                 "warning: Log %s unexpectedly ended on %s.\n",
1129                                                 logfile, show_rfc2822_date(date, tz));
1130                                 }
1131                         }
1132                         munmap(log_mapped, st.st_size);
1133                         return 0;
1134                 }
1135                 lastrec = rec;
1136                 if (cnt > 0)
1137                         cnt--;
1138         }
1139
1140         rec = logdata;
1141         while (rec < logend && *rec != '>' && *rec != '\n')
1142                 rec++;
1143         if (rec == logend || *rec == '\n')
1144                 die("Log %s is corrupt.", logfile);
1145         date = strtoul(rec + 1, &tz_c, 10);
1146         tz = strtoul(tz_c, NULL, 10);
1147         if (get_sha1_hex(logdata, sha1))
1148                 die("Log %s is corrupt.", logfile);
1149         if (msg)
1150                 *msg = ref_msg(logdata, logend);
1151         munmap(log_mapped, st.st_size);
1152
1153         if (cutoff_time)
1154                 *cutoff_time = date;
1155         if (cutoff_tz)
1156                 *cutoff_tz = tz;
1157         if (cutoff_cnt)
1158                 *cutoff_cnt = reccnt;
1159         return 1;
1160 }
1161
1162 int for_each_reflog_ent(const char *ref, each_reflog_ent_fn fn, void *cb_data)
1163 {
1164         const char *logfile;
1165         FILE *logfp;
1166         char buf[1024];
1167         int ret = 0;
1168
1169         logfile = git_path("logs/%s", ref);
1170         logfp = fopen(logfile, "r");
1171         if (!logfp)
1172                 return -1;
1173         while (fgets(buf, sizeof(buf), logfp)) {
1174                 unsigned char osha1[20], nsha1[20];
1175                 char *email_end, *message;
1176                 unsigned long timestamp;
1177                 int len, tz;
1178
1179                 /* old SP new SP name <email> SP time TAB msg LF */
1180                 len = strlen(buf);
1181                 if (len < 83 || buf[len-1] != '\n' ||
1182                     get_sha1_hex(buf, osha1) || buf[40] != ' ' ||
1183                     get_sha1_hex(buf + 41, nsha1) || buf[81] != ' ' ||
1184                     !(email_end = strchr(buf + 82, '>')) ||
1185                     email_end[1] != ' ' ||
1186                     !(timestamp = strtoul(email_end + 2, &message, 10)) ||
1187                     !message || message[0] != ' ' ||
1188                     (message[1] != '+' && message[1] != '-') ||
1189                     !isdigit(message[2]) || !isdigit(message[3]) ||
1190                     !isdigit(message[4]) || !isdigit(message[5]) ||
1191                     message[6] != '\t')
1192                         continue; /* corrupt? */
1193                 email_end[1] = '\0';
1194                 tz = strtol(message + 1, NULL, 10);
1195                 message += 7;
1196                 ret = fn(osha1, nsha1, buf+82, timestamp, tz, message, cb_data);
1197                 if (ret)
1198                         break;
1199         }
1200         fclose(logfp);
1201         return ret;
1202 }
1203