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 *entry;
  51
  52         /* Allocate it and add it in.. */
  53         len = strlen(name) + 1;
  54         entry = xmalloc(sizeof(struct ref_list) + len);
  55         hashcpy(entry->sha1, sha1);
  56         hashclr(entry->peeled);
  57         memcpy(entry->name, name, len);
  58         entry->flag = flag;
  59         entry->next = list;
  60         if (new_entry)
  61                 *new_entry = entry;
  62         return entry;
  63 }
  64
  65 /* merge sort the ref list */
  66 static struct ref_list *sort_ref_list(struct ref_list *list)
  67 {
  68         int psize, qsize, last_merge_count, cmp;
  69         struct ref_list *p, *q, *l, *e;
  70         struct ref_list *new_list = list;
  71         int k = 1;
  72         int merge_count = 0;
  73
  74         if (!list)
  75                 return list;
  76
  77         do {
  78                 last_merge_count = merge_count;
  79                 merge_count = 0;
  80
  81                 psize = 0;
  82
  83                 p = new_list;
  84                 q = new_list;
  85                 new_list = NULL;
  86                 l = NULL;
  87
  88                 while (p) {
  89                         merge_count++;
  90
  91                         while (psize < k && q->next) {
  92                                 q = q->next;
  93                                 psize++;
  94                         }
  95                         qsize = k;
  96
  97                         while ((psize > 0) || (qsize > 0 && q)) {
  98                                 if (qsize == 0 || !q) {
  99                                         e = p;
 100                                         p = p->next;
 101                                         psize--;
 102                                 } else if (psize == 0) {
 103                                         e = q;
 104                                         q = q->next;
 105                                         qsize--;
 106                                 } else {
 107                                         cmp = strcmp(q->name, p->name);
 108                                         if (cmp < 0) {
 109                                                 e = q;
 110                                                 q = q->next;
 111                                                 qsize--;
 112                                         } else if (cmp > 0) {
 113                                                 e = p;
 114                                                 p = p->next;
 115                                                 psize--;
 116                                         } else {
 117                                                 if (hashcmp(q->sha1, p->sha1))
 118                                                         die("Duplicated ref, and SHA1s don't match: %s",
 119                                                             q->name);
 120                                                 warning("Duplicated ref: %s", q->name);
 121                                                 e = q;
 122                                                 q = q->next;
 123                                                 qsize--;
 124                                                 free(e);
 125                                                 e = p;
 126                                                 p = p->next;
 127                                                 psize--;
 128                                         }
 129                                 }
 130
 131                                 e->next = NULL;
 132
 133                                 if (l)
 134                                         l->next = e;
 135                                 if (!new_list)
 136                                         new_list = e;
 137                                 l = e;
 138                         }
 139
 140                         p = q;
 141                 };
 142
 143                 k = k * 2;
 144         } while ((last_merge_count != merge_count) || (last_merge_count != 1));
 145
 146         return new_list;
 147 }
 148
 149 /*
 150  * Future: need to be in "struct repository"
 151  * when doing a full libification.
 152  */
 153 struct cached_refs {
 154         char did_loose;
 155         char did_packed;
 156         struct ref_list *loose;
 157         struct ref_list *packed;
 158 } cached_refs;
 159
 160 static void free_ref_list(struct ref_list *list)
 161 {
 162         struct ref_list *next;
 163         for ( ; list; list = next) {
 164                 next = list->next;
 165                 free(list);
 166         }
 167 }
 168
 169 static void invalidate_cached_refs(void)
 170 {
 171         struct cached_refs *ca = &cached_refs;
 172
 173         if (ca->did_loose && ca->loose)
 174                 free_ref_list(ca->loose);
 175         if (ca->did_packed && ca->packed)
 176                 free_ref_list(ca->packed);
 177         ca->loose = ca->packed = NULL;
 178         ca->did_loose = ca->did_packed = 0;
 179 }
 180
 181 static void read_packed_refs(FILE *f, struct cached_refs *cached_refs)
 182 {
 183         struct ref_list *list = NULL;
 184         struct ref_list *last = NULL;
 185         char refline[PATH_MAX];
 186         int flag = REF_ISPACKED;
 187
 188         while (fgets(refline, sizeof(refline), f)) {
 189                 unsigned char sha1[20];
 190                 const char *name;
 191                 static const char header[] = "# pack-refs with:";
 192
 193                 if (!strncmp(refline, header, sizeof(header)-1)) {
 194                         const char *traits = refline + sizeof(header) - 1;
 195                         if (strstr(traits, " peeled "))
 196                                 flag |= REF_KNOWS_PEELED;
 197                         /* perhaps other traits later as well */
 198                         continue;
 199                 }
 200
 201                 name = parse_ref_line(refline, sha1);
 202                 if (name) {
 203                         list = add_ref(name, sha1, flag, list, &last);
 204                         continue;
 205                 }
 206                 if (last &&
 207                     refline[0] == '^' &&
 208                     strlen(refline) == 42 &&
 209                     refline[41] == '\n' &&
 210                     !get_sha1_hex(refline + 1, sha1))
 211                         hashcpy(last->peeled, sha1);
 212         }
 213         cached_refs->packed = sort_ref_list(list);
 214 }
 215
 216 static struct ref_list *get_packed_refs(void)
 217 {
 218         if (!cached_refs.did_packed) {
 219                 FILE *f = fopen(git_path("packed-refs"), "r");
 220                 cached_refs.packed = NULL;
 221                 if (f) {
 222                         read_packed_refs(f, &cached_refs);
 223                         fclose(f);
 224                 }
 225                 cached_refs.did_packed = 1;
 226         }
 227         return cached_refs.packed;
 228 }
 229
 230 static struct ref_list *get_ref_dir(const char *base, struct ref_list *list)
 231 {
 232         DIR *dir = opendir(git_path("%s", base));
 233
 234         if (dir) {
 235                 struct dirent *de;
 236                 int baselen = strlen(base);
 237                 char *ref = xmalloc(baselen + 257);
 238
 239                 memcpy(ref, base, baselen);
 240                 if (baselen && base[baselen-1] != '/')
 241                         ref[baselen++] = '/';
 242
 243                 while ((de = readdir(dir)) != NULL) {
 244                         unsigned char sha1[20];
 245                         struct stat st;
 246                         int flag;
 247                         int namelen;
 248
 249                         if (de->d_name[0] == '.')
 250                                 continue;
 251                         namelen = strlen(de->d_name);
 252                         if (namelen > 255)
 253                                 continue;
 254                         if (has_extension(de->d_name, ".lock"))
 255                                 continue;
 256                         memcpy(ref + baselen, de->d_name, namelen+1);
 257                         if (stat(git_path("%s", ref), &st) < 0)
 258                                 continue;
 259                         if (S_ISDIR(st.st_mode)) {
 260                                 list = get_ref_dir(ref, list);
 261                                 continue;
 262                         }
 263                         if (!resolve_ref(ref, sha1, 1, &flag)) {
 264                                 error("%s points nowhere!", ref);
 265                                 continue;
 266                         }
 267                         list = add_ref(ref, sha1, flag, list, NULL);
 268                 }
 269                 free(ref);
 270                 closedir(dir);
 271         }
 272         return sort_ref_list(list);
 273 }
 274
 275 static struct ref_list *get_loose_refs(void)
 276 {
 277         if (!cached_refs.did_loose) {
 278                 cached_refs.loose = get_ref_dir("refs", NULL);
 279                 cached_refs.did_loose = 1;
 280         }
 281         return cached_refs.loose;
 282 }
 283
 284 /* We allow "recursive" symbolic refs. Only within reason, though */
 285 #define MAXDEPTH 5
 286
 287 const char *resolve_ref(const char *ref, unsigned char *sha1, int reading, int *flag)
 288 {
 289         int depth = MAXDEPTH, len;
 290         char buffer[256];
 291         static char ref_buffer[256];
 292
 293         if (flag)
 294                 *flag = 0;
 295
 296         for (;;) {
 297                 const char *path = git_path("%s", ref);
 298                 struct stat st;
 299                 char *buf;
 300                 int fd;
 301
 302                 if (--depth < 0)
 303                         return NULL;
 304
 305                 /* Special case: non-existing file.
 306                  * Not having the refs/heads/new-branch is OK
 307                  * if we are writing into it, so is .git/HEAD
 308                  * that points at refs/heads/master still to be
 309                  * born.  It is NOT OK if we are resolving for
 310                  * reading.
 311                  */
 312                 if (lstat(path, &st) < 0) {
 313                         struct ref_list *list = get_packed_refs();
 314                         while (list) {
 315                                 if (!strcmp(ref, list->name)) {
 316                                         hashcpy(sha1, list->sha1);
 317                                         if (flag)
 318                                                 *flag |= REF_ISPACKED;
 319                                         return ref;
 320                                 }
 321                                 list = list->next;
 322                         }
 323                         if (reading || errno != ENOENT)
 324                                 return NULL;
 325                         hashclr(sha1);
 326                         return ref;
 327                 }
 328
 329                 /* Follow "normalized" - ie "refs/.." symlinks by hand */
 330                 if (S_ISLNK(st.st_mode)) {
 331                         len = readlink(path, buffer, sizeof(buffer)-1);
 332                         if (len >= 5 && !memcmp("refs/", buffer, 5)) {
 333                                 buffer[len] = 0;
 334                                 strcpy(ref_buffer, buffer);
 335                                 ref = ref_buffer;
 336                                 if (flag)
 337                                         *flag |= REF_ISSYMREF;
 338                                 continue;
 339                         }
 340                 }
 341
 342                 /* Is it a directory? */
 343                 if (S_ISDIR(st.st_mode)) {
 344                         errno = EISDIR;
 345                         return NULL;
 346                 }
 347
 348                 /*
 349                  * Anything else, just open it and try to use it as
 350                  * a ref
 351                  */
 352                 fd = open(path, O_RDONLY);
 353                 if (fd < 0)
 354                         return NULL;
 355                 len = read_in_full(fd, buffer, sizeof(buffer)-1);
 356                 close(fd);
 357
 358                 /*
 359                  * Is it a symbolic ref?
 360                  */
 361                 if (len < 4 || memcmp("ref:", buffer, 4))
 362                         break;
 363                 buf = buffer + 4;
 364                 len -= 4;
 365                 while (len && isspace(*buf))
 366                         buf++, len--;
 367                 while (len && isspace(buf[len-1]))
 368                         len--;
 369                 buf[len] = 0;
 370                 memcpy(ref_buffer, buf, len + 1);
 371                 ref = ref_buffer;
 372                 if (flag)
 373                         *flag |= REF_ISSYMREF;
 374         }
 375         if (len < 40 || get_sha1_hex(buffer, sha1))
 376                 return NULL;
 377         return ref;
 378 }
 379
 380 int read_ref(const char *ref, unsigned char *sha1)
 381 {
 382         if (resolve_ref(ref, sha1, 1, NULL))
 383                 return 0;
 384         return -1;
 385 }
 386
 387 static int do_one_ref(const char *base, each_ref_fn fn, int trim,
 388                       void *cb_data, struct ref_list *entry)
 389 {
 390         if (strncmp(base, entry->name, trim))
 391                 return 0;
 392         if (is_null_sha1(entry->sha1))
 393                 return 0;
 394         if (!has_sha1_file(entry->sha1)) {
 395                 error("%s does not point to a valid object!", entry->name);
 396                 return 0;
 397         }
 398         return fn(entry->name + trim, entry->sha1, entry->flag, cb_data);
 399 }
 400
 401 int peel_ref(const char *ref, unsigned char *sha1)
 402 {
 403         int flag;
 404         unsigned char base[20];
 405         struct object *o;
 406
 407         if (!resolve_ref(ref, base, 1, &flag))
 408                 return -1;
 409
 410         if ((flag & REF_ISPACKED)) {
 411                 struct ref_list *list = get_packed_refs();
 412
 413                 while (list) {
 414                         if (!strcmp(list->name, ref)) {
 415                                 if (list->flag & REF_KNOWS_PEELED) {
 416                                         hashcpy(sha1, list->peeled);
 417                                         return 0;
 418                                 }
 419                                 /* older pack-refs did not leave peeled ones */
 420                                 break;
 421                         }
 422                         list = list->next;
 423                 }
 424         }
 425
 426         /* fallback - callers should not call this for unpacked refs */
 427         o = parse_object(base);
 428         if (o->type == OBJ_TAG) {
 429                 o = deref_tag(o, ref, 0);
 430                 if (o) {
 431                         hashcpy(sha1, o->sha1);
 432                         return 0;
 433                 }
 434         }
 435         return -1;
 436 }
 437
 438 static int do_for_each_ref(const char *base, each_ref_fn fn, int trim,
 439                            void *cb_data)
 440 {
 441         int retval;
 442         struct ref_list *packed = get_packed_refs();
 443         struct ref_list *loose = get_loose_refs();
 444
 445         while (packed && loose) {
 446                 struct ref_list *entry;
 447                 int cmp = strcmp(packed->name, loose->name);
 448                 if (!cmp) {
 449                         packed = packed->next;
 450                         continue;
 451                 }
 452                 if (cmp > 0) {
 453                         entry = loose;
 454                         loose = loose->next;
 455                 } else {
 456                         entry = packed;
 457                         packed = packed->next;
 458                 }
 459                 retval = do_one_ref(base, fn, trim, cb_data, entry);
 460                 if (retval)
 461                         return retval;
 462         }
 463
 464         for (packed = packed ? packed : loose; packed; packed = packed->next) {
 465                 retval = do_one_ref(base, fn, trim, cb_data, packed);
 466                 if (retval)
 467                         return retval;
 468         }
 469         return 0;
 470 }
 471
 472 int head_ref(each_ref_fn fn, void *cb_data)
 473 {
 474         unsigned char sha1[20];
 475         int flag;
 476
 477         if (resolve_ref("HEAD", sha1, 1, &flag))
 478                 return fn("HEAD", sha1, flag, cb_data);
 479         return 0;
 480 }
 481
 482 int for_each_ref(each_ref_fn fn, void *cb_data)
 483 {
 484         return do_for_each_ref("refs/", fn, 0, cb_data);
 485 }
 486
 487 int for_each_tag_ref(each_ref_fn fn, void *cb_data)
 488 {
 489         return do_for_each_ref("refs/tags/", fn, 10, cb_data);
 490 }
 491
 492 int for_each_branch_ref(each_ref_fn fn, void *cb_data)
 493 {
 494         return do_for_each_ref("refs/heads/", fn, 11, cb_data);
 495 }
 496
 497 int for_each_remote_ref(each_ref_fn fn, void *cb_data)
 498 {
 499         return do_for_each_ref("refs/remotes/", fn, 13, cb_data);
 500 }
 501
 502 /* NEEDSWORK: This is only used by ssh-upload and it should go; the
 503  * caller should do resolve_ref or read_ref like everybody else.  Or
 504  * maybe everybody else should use get_ref_sha1() instead of doing
 505  * read_ref().
 506  */
 507 int get_ref_sha1(const char *ref, unsigned char *sha1)
 508 {
 509         if (check_ref_format(ref))
 510                 return -1;
 511         return read_ref(mkpath("refs/%s", ref), sha1);
 512 }
 513
 514 /*
 515  * Make sure "ref" is something reasonable to have under ".git/refs/";
 516  * We do not like it if:
 517  *
 518  * - any path component of it begins with ".", or
 519  * - it has double dots "..", or
 520  * - it has ASCII control character, "~", "^", ":" or SP, anywhere, or
 521  * - it ends with a "/".
 522  */
 523
 524 static inline int bad_ref_char(int ch)
 525 {
 526         return (((unsigned) ch) <= ' ' ||
 527                 ch == '~' || ch == '^' || ch == ':' ||
 528                 /* 2.13 Pattern Matching Notation */
 529                 ch == '?' || ch == '*' || ch == '[');
 530 }
 531
 532 int check_ref_format(const char *ref)
 533 {
 534         int ch, level;
 535         const char *cp = ref;
 536
 537         level = 0;
 538         while (1) {
 539                 while ((ch = *cp++) == '/')
 540                         ; /* tolerate duplicated slashes */
 541                 if (!ch)
 542                         return -1; /* should not end with slashes */
 543
 544                 /* we are at the beginning of the path component */
 545                 if (ch == '.' || bad_ref_char(ch))
 546                         return -1;
 547
 548                 /* scan the rest of the path component */
 549                 while ((ch = *cp++) != 0) {
 550                         if (bad_ref_char(ch))
 551                                 return -1;
 552                         if (ch == '/')
 553                                 break;
 554                         if (ch == '.' && *cp == '.')
 555                                 return -1;
 556                 }
 557                 level++;
 558                 if (!ch) {
 559                         if (level < 2)
 560                                 return -2; /* at least of form "heads/blah" */
 561                         return 0;
 562                 }
 563         }
 564 }
 565
 566 static struct ref_lock *verify_lock(struct ref_lock *lock,
 567         const unsigned char *old_sha1, int mustexist)
 568 {
 569         if (!resolve_ref(lock->ref_name, lock->old_sha1, mustexist, NULL)) {
 570                 error("Can't verify ref %s", lock->ref_name);
 571                 unlock_ref(lock);
 572                 return NULL;
 573         }
 574         if (hashcmp(lock->old_sha1, old_sha1)) {
 575                 error("Ref %s is at %s but expected %s", lock->ref_name,
 576                         sha1_to_hex(lock->old_sha1), sha1_to_hex(old_sha1));
 577                 unlock_ref(lock);
 578                 return NULL;
 579         }
 580         return lock;
 581 }
 582
 583 static int remove_empty_dir_recursive(char *path, int len)
 584 {
 585         DIR *dir = opendir(path);
 586         struct dirent *e;
 587         int ret = 0;
 588
 589         if (!dir)
 590                 return -1;
 591         if (path[len-1] != '/')
 592                 path[len++] = '/';
 593         while ((e = readdir(dir)) != NULL) {
 594                 struct stat st;
 595                 int namlen;
 596                 if ((e->d_name[0] == '.') &&
 597                     ((e->d_name[1] == 0) ||
 598                      ((e->d_name[1] == '.') && e->d_name[2] == 0)))
 599                         continue; /* "." and ".." */
 600
 601                 namlen = strlen(e->d_name);
 602                 if ((len + namlen < PATH_MAX) &&
 603                     strcpy(path + len, e->d_name) &&
 604                     !lstat(path, &st) &&
 605                     S_ISDIR(st.st_mode) &&
 606                     !remove_empty_dir_recursive(path, len + namlen))
 607                         continue; /* happy */
 608
 609                 /* path too long, stat fails, or non-directory still exists */
 610                 ret = -1;
 611                 break;
 612         }
 613         closedir(dir);
 614         if (!ret) {
 615                 path[len] = 0;
 616                 ret = rmdir(path);
 617         }
 618         return ret;
 619 }
 620
 621 static int remove_empty_directories(char *file)
 622 {
 623         /* we want to create a file but there is a directory there;
 624          * if that is an empty directory (or a directory that contains
 625          * only empty directories), remove them.
 626          */
 627         char path[PATH_MAX];
 628         int len = strlen(file);
 629
 630         if (len >= PATH_MAX) /* path too long ;-) */
 631                 return -1;
 632         strcpy(path, file);
 633         return remove_empty_dir_recursive(path, len);
 634 }
 635
 636 static int is_refname_available(const char *ref, const char *oldref,
 637                                 struct ref_list *list, int quiet)
 638 {
 639         int namlen = strlen(ref); /* e.g. 'foo/bar' */
 640         while (list) {
 641                 /* list->name could be 'foo' or 'foo/bar/baz' */
 642                 if (!oldref || strcmp(oldref, list->name)) {
 643                         int len = strlen(list->name);
 644                         int cmplen = (namlen < len) ? namlen : len;
 645                         const char *lead = (namlen < len) ? list->name : ref;
 646                         if (!strncmp(ref, list->name, cmplen) &&
 647                             lead[cmplen] == '/') {
 648                                 if (!quiet)
 649                                         error("'%s' exists; cannot create '%s'",
 650                                               list->name, ref);
 651                                 return 0;
 652                         }
 653                 }
 654                 list = list->next;
 655         }
 656         return 1;
 657 }
 658
 659 static struct ref_lock *lock_ref_sha1_basic(const char *ref, const unsigned char *old_sha1, int *flag)
 660 {
 661         char *ref_file;
 662         const char *orig_ref = ref;
 663         struct ref_lock *lock;
 664         struct stat st;
 665         int last_errno = 0;
 666         int mustexist = (old_sha1 && !is_null_sha1(old_sha1));
 667
 668         lock = xcalloc(1, sizeof(struct ref_lock));
 669         lock->lock_fd = -1;
 670
 671         ref = resolve_ref(ref, lock->old_sha1, mustexist, flag);
 672         if (!ref && errno == EISDIR) {
 673                 /* we are trying to lock foo but we used to
 674                  * have foo/bar which now does not exist;
 675                  * it is normal for the empty directory 'foo'
 676                  * to remain.
 677                  */
 678                 ref_file = git_path("%s", orig_ref);
 679                 if (remove_empty_directories(ref_file)) {
 680                         last_errno = errno;
 681                         error("there are still refs under '%s'", orig_ref);
 682                         goto error_return;
 683                 }
 684                 ref = resolve_ref(orig_ref, lock->old_sha1, mustexist, flag);
 685         }
 686         if (!ref) {
 687                 last_errno = errno;
 688                 error("unable to resolve reference %s: %s",
 689                         orig_ref, strerror(errno));
 690                 goto error_return;
 691         }
 692         /* When the ref did not exist and we are creating it,
 693          * make sure there is no existing ref that is packed
 694          * whose name begins with our refname, nor a ref whose
 695          * name is a proper prefix of our refname.
 696          */
 697         if (is_null_sha1(lock->old_sha1) &&
 698             !is_refname_available(ref, NULL, get_packed_refs(), 0))
 699                 goto error_return;
 700
 701         lock->lk = xcalloc(1, sizeof(struct lock_file));
 702
 703         lock->ref_name = xstrdup(ref);
 704         lock->orig_ref_name = xstrdup(orig_ref);
 705         ref_file = git_path("%s", ref);
 706         lock->force_write = lstat(ref_file, &st) && errno == ENOENT;
 707
 708         if (safe_create_leading_directories(ref_file)) {
 709                 last_errno = errno;
 710                 error("unable to create directory for %s", ref_file);
 711                 goto error_return;
 712         }
 713         lock->lock_fd = hold_lock_file_for_update(lock->lk, ref_file, 1);
 714
 715         return old_sha1 ? verify_lock(lock, old_sha1, mustexist) : lock;
 716
 717  error_return:
 718         unlock_ref(lock);
 719         errno = last_errno;
 720         return NULL;
 721 }
 722
 723 struct ref_lock *lock_ref_sha1(const char *ref, const unsigned char *old_sha1)
 724 {
 725         char refpath[PATH_MAX];
 726         if (check_ref_format(ref))
 727                 return NULL;
 728         strcpy(refpath, mkpath("refs/%s", ref));
 729         return lock_ref_sha1_basic(refpath, old_sha1, NULL);
 730 }
 731
 732 struct ref_lock *lock_any_ref_for_update(const char *ref, const unsigned char *old_sha1)
 733 {
 734         if (check_ref_format(ref) == -1)
 735                 return NULL;
 736         return lock_ref_sha1_basic(ref, old_sha1, NULL);
 737 }
 738
 739 static struct lock_file packlock;
 740
 741 static int repack_without_ref(const char *refname)
 742 {
 743         struct ref_list *list, *packed_ref_list;
 744         int fd;
 745         int found = 0;
 746
 747         packed_ref_list = get_packed_refs();
 748         for (list = packed_ref_list; list; list = list->next) {
 749                 if (!strcmp(refname, list->name)) {
 750                         found = 1;
 751                         break;
 752                 }
 753         }
 754         if (!found)
 755                 return 0;
 756         fd = hold_lock_file_for_update(&packlock, git_path("packed-refs"), 0);
 757         if (fd < 0)
 758                 return error("cannot delete '%s' from packed refs", refname);
 759
 760         for (list = packed_ref_list; list; list = list->next) {
 761                 char line[PATH_MAX + 100];
 762                 int len;
 763
 764                 if (!strcmp(refname, list->name))
 765                         continue;
 766                 len = snprintf(line, sizeof(line), "%s %s\n",
 767                                sha1_to_hex(list->sha1), list->name);
 768                 /* this should not happen but just being defensive */
 769                 if (len > sizeof(line))
 770                         die("too long a refname '%s'", list->name);
 771                 write_or_die(fd, line, len);
 772         }
 773         return commit_lock_file(&packlock);
 774 }
 775
 776 int delete_ref(const char *refname, const unsigned char *sha1)
 777 {
 778         struct ref_lock *lock;
 779         int err, i, ret = 0, flag = 0;
 780
 781         lock = lock_ref_sha1_basic(refname, sha1, &flag);
 782         if (!lock)
 783                 return 1;
 784         if (!(flag & REF_ISPACKED)) {
 785                 /* loose */
 786                 i = strlen(lock->lk->filename) - 5; /* .lock */
 787                 lock->lk->filename[i] = 0;
 788                 err = unlink(lock->lk->filename);
 789                 if (err) {
 790                         ret = 1;
 791                         error("unlink(%s) failed: %s",
 792                               lock->lk->filename, strerror(errno));
 793                 }
 794                 lock->lk->filename[i] = '.';
 795         }
 796         /* removing the loose one could have resurrected an earlier
 797          * packed one.  Also, if it was not loose we need to repack
 798          * without it.
 799          */
 800         ret |= repack_without_ref(refname);
 801
 802         err = unlink(git_path("logs/%s", lock->ref_name));
 803         if (err && errno != ENOENT)
 804                 fprintf(stderr, "warning: unlink(%s) failed: %s",
 805                         git_path("logs/%s", lock->ref_name), strerror(errno));
 806         invalidate_cached_refs();
 807         unlock_ref(lock);
 808         return ret;
 809 }
 810
 811 int rename_ref(const char *oldref, const char *newref, const char *logmsg)
 812 {
 813         static const char renamed_ref[] = "RENAMED-REF";
 814         unsigned char sha1[20], orig_sha1[20];
 815         int flag = 0, logmoved = 0;
 816         struct ref_lock *lock;
 817         struct stat loginfo;
 818         int log = !lstat(git_path("logs/%s", oldref), &loginfo);
 819
 820         if (S_ISLNK(loginfo.st_mode))
 821                 return error("reflog for %s is a symlink", oldref);
 822
 823         if (!resolve_ref(oldref, orig_sha1, 1, &flag))
 824                 return error("refname %s not found", oldref);
 825
 826         if (!is_refname_available(newref, oldref, get_packed_refs(), 0))
 827                 return 1;
 828
 829         if (!is_refname_available(newref, oldref, get_loose_refs(), 0))
 830                 return 1;
 831
 832         lock = lock_ref_sha1_basic(renamed_ref, NULL, NULL);
 833         if (!lock)
 834                 return error("unable to lock %s", renamed_ref);
 835         lock->force_write = 1;
 836         if (write_ref_sha1(lock, orig_sha1, logmsg))
 837                 return error("unable to save current sha1 in %s", renamed_ref);
 838
 839         if (log && rename(git_path("logs/%s", oldref), git_path("tmp-renamed-log")))
 840                 return error("unable to move logfile logs/%s to tmp-renamed-log: %s",
 841                         oldref, strerror(errno));
 842
 843         if (delete_ref(oldref, orig_sha1)) {
 844                 error("unable to delete old %s", oldref);
 845                 goto rollback;
 846         }
 847
 848         if (resolve_ref(newref, sha1, 1, &flag) && delete_ref(newref, sha1)) {
 849                 if (errno==EISDIR) {
 850                         if (remove_empty_directories(git_path("%s", newref))) {
 851                                 error("Directory not empty: %s", newref);
 852                                 goto rollback;
 853                         }
 854                 } else {
 855                         error("unable to delete existing %s", newref);
 856                         goto rollback;
 857                 }
 858         }
 859
 860         if (log && safe_create_leading_directories(git_path("logs/%s", newref))) {
 861                 error("unable to create directory for %s", newref);
 862                 goto rollback;
 863         }
 864
 865  retry:
 866         if (log && rename(git_path("tmp-renamed-log"), git_path("logs/%s", newref))) {
 867                 if (errno==EISDIR || errno==ENOTDIR) {
 868                         /*
 869                          * rename(a, b) when b is an existing
 870                          * directory ought to result in ISDIR, but
 871                          * Solaris 5.8 gives ENOTDIR.  Sheesh.
 872                          */
 873                         if (remove_empty_directories(git_path("logs/%s", newref))) {
 874                                 error("Directory not empty: logs/%s", newref);
 875                                 goto rollback;
 876                         }
 877                         goto retry;
 878                 } else {
 879                         error("unable to move logfile tmp-renamed-log to logs/%s: %s",
 880                                 newref, strerror(errno));
 881                         goto rollback;
 882                 }
 883         }
 884         logmoved = log;
 885
 886         lock = lock_ref_sha1_basic(newref, NULL, NULL);
 887         if (!lock) {
 888                 error("unable to lock %s for update", newref);
 889                 goto rollback;
 890         }
 891
 892         lock->force_write = 1;
 893         hashcpy(lock->old_sha1, orig_sha1);
 894         if (write_ref_sha1(lock, orig_sha1, logmsg)) {
 895                 error("unable to write current sha1 into %s", newref);
 896                 goto rollback;
 897         }
 898
 899         return 0;
 900
 901  rollback:
 902         lock = lock_ref_sha1_basic(oldref, NULL, NULL);
 903         if (!lock) {
 904                 error("unable to lock %s for rollback", oldref);
 905                 goto rollbacklog;
 906         }
 907
 908         lock->force_write = 1;
 909         flag = log_all_ref_updates;
 910         log_all_ref_updates = 0;
 911         if (write_ref_sha1(lock, orig_sha1, NULL))
 912                 error("unable to write current sha1 into %s", oldref);
 913         log_all_ref_updates = flag;
 914
 915  rollbacklog:
 916         if (logmoved && rename(git_path("logs/%s", newref), git_path("logs/%s", oldref)))
 917                 error("unable to restore logfile %s from %s: %s",
 918                         oldref, newref, strerror(errno));
 919         if (!logmoved && log &&
 920             rename(git_path("tmp-renamed-log"), git_path("logs/%s", oldref)))
 921                 error("unable to restore logfile %s from tmp-renamed-log: %s",
 922                         oldref, strerror(errno));
 923
 924         return 1;
 925 }
 926
 927 void unlock_ref(struct ref_lock *lock)
 928 {
 929         if (lock->lock_fd >= 0) {
 930                 close(lock->lock_fd);
 931                 /* Do not free lock->lk -- atexit() still looks at them */
 932                 if (lock->lk)
 933                         rollback_lock_file(lock->lk);
 934         }
 935         free(lock->ref_name);
 936         free(lock->orig_ref_name);
 937         free(lock);
 938 }
 939
 940 static int log_ref_write(const char *ref_name, const unsigned char *old_sha1,
 941                          const unsigned char *new_sha1, const char *msg)
 942 {
 943         int logfd, written, oflags = O_APPEND | O_WRONLY;
 944         unsigned maxlen, len;
 945         int msglen;
 946         char *log_file, *logrec;
 947         const char *committer;
 948
 949         if (log_all_ref_updates < 0)
 950                 log_all_ref_updates = !is_bare_repository();
 951
 952         log_file = git_path("logs/%s", ref_name);
 953
 954         if (log_all_ref_updates &&
 955             (!prefixcmp(ref_name, "refs/heads/") ||
 956              !prefixcmp(ref_name, "refs/remotes/") ||
 957              !strcmp(ref_name, "HEAD"))) {
 958                 if (safe_create_leading_directories(log_file) < 0)
 959                         return error("unable to create directory for %s",
 960                                      log_file);
 961                 oflags |= O_CREAT;
 962         }
 963
 964         logfd = open(log_file, oflags, 0666);
 965         if (logfd < 0) {
 966                 if (!(oflags & O_CREAT) && errno == ENOENT)
 967                         return 0;
 968
 969                 if ((oflags & O_CREAT) && errno == EISDIR) {
 970                         if (remove_empty_directories(log_file)) {
 971                                 return error("There are still logs under '%s'",
 972                                              log_file);
 973                         }
 974                         logfd = open(log_file, oflags, 0666);
 975                 }
 976
 977                 if (logfd < 0)
 978                         return error("Unable to append to %s: %s",
 979                                      log_file, strerror(errno));
 980         }
 981
 982         adjust_shared_perm(log_file);
 983
 984         msglen = 0;
 985         if (msg) {
 986                 /* clean up the message and make sure it is a single line */
 987                 for ( ; *msg; msg++)
 988                         if (!isspace(*msg))
 989                                 break;
 990                 if (*msg) {
 991                         const char *ep = strchr(msg, '\n');
 992                         if (ep)
 993                                 msglen = ep - msg;
 994                         else
 995                                 msglen = strlen(msg);
 996                 }
 997         }
 998
 999         committer = git_committer_info(-1);
1000         maxlen = strlen(committer) + msglen + 100;
1001         logrec = xmalloc(maxlen);
1002         len = sprintf(logrec, "%s %s %s\n",
1003                       sha1_to_hex(old_sha1),
1004                       sha1_to_hex(new_sha1),
1005                       committer);
1006         if (msglen)
1007                 len += sprintf(logrec + len - 1, "\t%.*s\n", msglen, msg) - 1;
1008         written = len <= maxlen ? write_in_full(logfd, logrec, len) : -1;
1009         free(logrec);
1010         close(logfd);
1011         if (written != len)
1012                 return error("Unable to append to %s", log_file);
1013         return 0;
1014 }
1015
1016 int write_ref_sha1(struct ref_lock *lock,
1017         const unsigned char *sha1, const char *logmsg)
1018 {
1019         static char term = '\n';
1020
1021         if (!lock)
1022                 return -1;
1023         if (!lock->force_write && !hashcmp(lock->old_sha1, sha1)) {
1024                 unlock_ref(lock);
1025                 return 0;
1026         }
1027         if (write_in_full(lock->lock_fd, sha1_to_hex(sha1), 40) != 40 ||
1028             write_in_full(lock->lock_fd, &term, 1) != 1
1029                 || close(lock->lock_fd) < 0) {
1030                 error("Couldn't write %s", lock->lk->filename);
1031                 unlock_ref(lock);
1032                 return -1;
1033         }
1034         invalidate_cached_refs();
1035         if (log_ref_write(lock->ref_name, lock->old_sha1, sha1, logmsg) < 0 ||
1036             (strcmp(lock->ref_name, lock->orig_ref_name) &&
1037              log_ref_write(lock->orig_ref_name, lock->old_sha1, sha1, logmsg) < 0)) {
1038                 unlock_ref(lock);
1039                 return -1;
1040         }
1041         if (strcmp(lock->orig_ref_name, "HEAD") != 0) {
1042                 /*
1043                  * Special hack: If a branch is updated directly and HEAD
1044                  * points to it (may happen on the remote side of a push
1045                  * for example) then logically the HEAD reflog should be
1046                  * updated too.
1047                  * A generic solution implies reverse symref information,
1048                  * but finding all symrefs pointing to the given branch
1049                  * would be rather costly for this rare event (the direct
1050                  * update of a branch) to be worth it.  So let's cheat and
1051                  * check with HEAD only which should cover 99% of all usage
1052                  * scenarios (even 100% of the default ones).
1053                  */
1054                 unsigned char head_sha1[20];
1055                 int head_flag;
1056                 const char *head_ref;
1057                 head_ref = resolve_ref("HEAD", head_sha1, 1, &head_flag);
1058                 if (head_ref && (head_flag & REF_ISSYMREF) &&
1059                     !strcmp(head_ref, lock->ref_name))
1060                         log_ref_write("HEAD", lock->old_sha1, sha1, logmsg);
1061         }
1062         if (commit_lock_file(lock->lk)) {
1063                 error("Couldn't set %s", lock->ref_name);
1064                 unlock_ref(lock);
1065                 return -1;
1066         }
1067         lock->lock_fd = -1;
1068         unlock_ref(lock);
1069         return 0;
1070 }
1071
1072 int create_symref(const char *ref_target, const char *refs_heads_master,
1073                   const char *logmsg)
1074 {
1075         const char *lockpath;
1076         char ref[1000];
1077         int fd, len, written;
1078         char *git_HEAD = xstrdup(git_path("%s", ref_target));
1079         unsigned char old_sha1[20], new_sha1[20];
1080
1081         if (logmsg && read_ref(ref_target, old_sha1))
1082                 hashclr(old_sha1);
1083
1084         if (safe_create_leading_directories(git_HEAD) < 0)
1085                 return error("unable to create directory for %s", git_HEAD);
1086
1087 #ifndef NO_SYMLINK_HEAD
1088         if (prefer_symlink_refs) {
1089                 unlink(git_HEAD);
1090                 if (!symlink(refs_heads_master, git_HEAD))
1091                         goto done;
1092                 fprintf(stderr, "no symlink - falling back to symbolic ref\n");
1093         }
1094 #endif
1095
1096         len = snprintf(ref, sizeof(ref), "ref: %s\n", refs_heads_master);
1097         if (sizeof(ref) <= len) {
1098                 error("refname too long: %s", refs_heads_master);
1099                 goto error_free_return;
1100         }
1101         lockpath = mkpath("%s.lock", git_HEAD);
1102         fd = open(lockpath, O_CREAT | O_EXCL | O_WRONLY, 0666);
1103         if (fd < 0) {
1104                 error("Unable to open %s for writing", lockpath);
1105                 goto error_free_return;
1106         }
1107         written = write_in_full(fd, ref, len);
1108         close(fd);
1109         if (written != len) {
1110                 error("Unable to write to %s", lockpath);
1111                 goto error_unlink_return;
1112         }
1113         if (rename(lockpath, git_HEAD) < 0) {
1114                 error("Unable to create %s", git_HEAD);
1115                 goto error_unlink_return;
1116         }
1117         if (adjust_shared_perm(git_HEAD)) {
1118                 error("Unable to fix permissions on %s", lockpath);
1119         error_unlink_return:
1120                 unlink(lockpath);
1121         error_free_return:
1122                 free(git_HEAD);
1123                 return -1;
1124         }
1125
1126 #ifndef NO_SYMLINK_HEAD
1127         done:
1128 #endif
1129         if (logmsg && !read_ref(refs_heads_master, new_sha1))
1130                 log_ref_write(ref_target, old_sha1, new_sha1, logmsg);
1131
1132         free(git_HEAD);
1133         return 0;
1134 }
1135
1136 static char *ref_msg(const char *line, const char *endp)
1137 {
1138         const char *ep;
1139         char *msg;
1140
1141         line += 82;
1142         for (ep = line; ep < endp && *ep != '\n'; ep++)
1143                 ;
1144         msg = xmalloc(ep - line + 1);
1145         memcpy(msg, line, ep - line);
1146         msg[ep - line] = 0;
1147         return msg;
1148 }
1149
1150 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)
1151 {
1152         const char *logfile, *logdata, *logend, *rec, *lastgt, *lastrec;
1153         char *tz_c;
1154         int logfd, tz, reccnt = 0;
1155         struct stat st;
1156         unsigned long date;
1157         unsigned char logged_sha1[20];
1158         void *log_mapped;
1159         size_t mapsz;
1160
1161         logfile = git_path("logs/%s", ref);
1162         logfd = open(logfile, O_RDONLY, 0);
1163         if (logfd < 0)
1164                 die("Unable to read log %s: %s", logfile, strerror(errno));
1165         fstat(logfd, &st);
1166         if (!st.st_size)
1167                 die("Log %s is empty.", logfile);
1168         mapsz = xsize_t(st.st_size);
1169         log_mapped = xmmap(NULL, mapsz, PROT_READ, MAP_PRIVATE, logfd, 0);
1170         logdata = log_mapped;
1171         close(logfd);
1172
1173         lastrec = NULL;
1174         rec = logend = logdata + st.st_size;
1175         while (logdata < rec) {
1176                 reccnt++;
1177                 if (logdata < rec && *(rec-1) == '\n')
1178                         rec--;
1179                 lastgt = NULL;
1180                 while (logdata < rec && *(rec-1) != '\n') {
1181                         rec--;
1182                         if (*rec == '>')
1183                                 lastgt = rec;
1184                 }
1185                 if (!lastgt)
1186                         die("Log %s is corrupt.", logfile);
1187                 date = strtoul(lastgt + 1, &tz_c, 10);
1188                 if (date <= at_time || cnt == 0) {
1189                         tz = strtoul(tz_c, NULL, 10);
1190                         if (msg)
1191                                 *msg = ref_msg(rec, logend);
1192                         if (cutoff_time)
1193                                 *cutoff_time = date;
1194                         if (cutoff_tz)
1195                                 *cutoff_tz = tz;
1196                         if (cutoff_cnt)
1197                                 *cutoff_cnt = reccnt - 1;
1198                         if (lastrec) {
1199                                 if (get_sha1_hex(lastrec, logged_sha1))
1200                                         die("Log %s is corrupt.", logfile);
1201                                 if (get_sha1_hex(rec + 41, sha1))
1202                                         die("Log %s is corrupt.", logfile);
1203                                 if (hashcmp(logged_sha1, sha1)) {
1204                                         fprintf(stderr,
1205                                                 "warning: Log %s has gap after %s.\n",
1206                                                 logfile, show_rfc2822_date(date, tz));
1207                                 }
1208                         }
1209                         else if (date == at_time) {
1210                                 if (get_sha1_hex(rec + 41, sha1))
1211                                         die("Log %s is corrupt.", logfile);
1212                         }
1213                         else {
1214                                 if (get_sha1_hex(rec + 41, logged_sha1))
1215                                         die("Log %s is corrupt.", logfile);
1216                                 if (hashcmp(logged_sha1, sha1)) {
1217                                         fprintf(stderr,
1218                                                 "warning: Log %s unexpectedly ended on %s.\n",
1219                                                 logfile, show_rfc2822_date(date, tz));
1220                                 }
1221                         }
1222                         munmap(log_mapped, mapsz);
1223                         return 0;
1224                 }
1225                 lastrec = rec;
1226                 if (cnt > 0)
1227                         cnt--;
1228         }
1229
1230         rec = logdata;
1231         while (rec < logend && *rec != '>' && *rec != '\n')
1232                 rec++;
1233         if (rec == logend || *rec == '\n')
1234                 die("Log %s is corrupt.", logfile);
1235         date = strtoul(rec + 1, &tz_c, 10);
1236         tz = strtoul(tz_c, NULL, 10);
1237         if (get_sha1_hex(logdata, sha1))
1238                 die("Log %s is corrupt.", logfile);
1239         if (msg)
1240                 *msg = ref_msg(logdata, logend);
1241         munmap(log_mapped, mapsz);
1242
1243         if (cutoff_time)
1244                 *cutoff_time = date;
1245         if (cutoff_tz)
1246                 *cutoff_tz = tz;
1247         if (cutoff_cnt)
1248                 *cutoff_cnt = reccnt;
1249         return 1;
1250 }
1251
1252 int for_each_reflog_ent(const char *ref, each_reflog_ent_fn fn, void *cb_data)
1253 {
1254         const char *logfile;
1255         FILE *logfp;
1256         char buf[1024];
1257         int ret = 0;
1258
1259         logfile = git_path("logs/%s", ref);
1260         logfp = fopen(logfile, "r");
1261         if (!logfp)
1262                 return -1;
1263         while (fgets(buf, sizeof(buf), logfp)) {
1264                 unsigned char osha1[20], nsha1[20];
1265                 char *email_end, *message;
1266                 unsigned long timestamp;
1267                 int len, tz;
1268
1269                 /* old SP new SP name <email> SP time TAB msg LF */
1270                 len = strlen(buf);
1271                 if (len < 83 || buf[len-1] != '\n' ||
1272                     get_sha1_hex(buf, osha1) || buf[40] != ' ' ||
1273                     get_sha1_hex(buf + 41, nsha1) || buf[81] != ' ' ||
1274                     !(email_end = strchr(buf + 82, '>')) ||
1275                     email_end[1] != ' ' ||
1276                     !(timestamp = strtoul(email_end + 2, &message, 10)) ||
1277                     !message || message[0] != ' ' ||
1278                     (message[1] != '+' && message[1] != '-') ||
1279                     !isdigit(message[2]) || !isdigit(message[3]) ||
1280                     !isdigit(message[4]) || !isdigit(message[5]))
1281                         continue; /* corrupt? */
1282                 email_end[1] = '\0';
1283                 tz = strtol(message + 1, NULL, 10);
1284                 if (message[6] != '\t')
1285                         message += 6;
1286                 else
1287                         message += 7;
1288                 ret = fn(osha1, nsha1, buf+82, timestamp, tz, message, cb_data);
1289                 if (ret)
1290                         break;
1291         }
1292         fclose(logfp);
1293         return ret;
1294 }
1295
1296 static int do_for_each_reflog(const char *base, each_ref_fn fn, void *cb_data)
1297 {
1298         DIR *dir = opendir(git_path("logs/%s", base));
1299         int retval = 0;
1300
1301         if (dir) {
1302                 struct dirent *de;
1303                 int baselen = strlen(base);
1304                 char *log = xmalloc(baselen + 257);
1305
1306                 memcpy(log, base, baselen);
1307                 if (baselen && base[baselen-1] != '/')
1308                         log[baselen++] = '/';
1309
1310                 while ((de = readdir(dir)) != NULL) {
1311                         struct stat st;
1312                         int namelen;
1313
1314                         if (de->d_name[0] == '.')
1315                                 continue;
1316                         namelen = strlen(de->d_name);
1317                         if (namelen > 255)
1318                                 continue;
1319                         if (has_extension(de->d_name, ".lock"))
1320                                 continue;
1321                         memcpy(log + baselen, de->d_name, namelen+1);
1322                         if (stat(git_path("logs/%s", log), &st) < 0)
1323                                 continue;
1324                         if (S_ISDIR(st.st_mode)) {
1325                                 retval = do_for_each_reflog(log, fn, cb_data);
1326                         } else {
1327                                 unsigned char sha1[20];
1328                                 if (!resolve_ref(log, sha1, 0, NULL))
1329                                         retval = error("bad ref for %s", log);
1330                                 else
1331                                         retval = fn(log, sha1, 0, cb_data);
1332                         }
1333                         if (retval)
1334                                 break;
1335                 }
1336                 free(log);
1337                 closedir(dir);
1338         }
1339         else if (*base)
1340                 return errno;
1341         return retval;
1342 }
1343
1344 int for_each_reflog(each_ref_fn fn, void *cb_data)
1345 {
1346         return do_for_each_reflog("", fn, cb_data);
1347 }