refs.c

   1 #include "cache.h"
   2 #include "refs.h"
   3 #include "object.h"
   4 #include "tag.h"
   5 #include "dir.h"
   6
   7 /* ISSYMREF=01 and ISPACKED=02 are public interfaces */
   8 #define REF_KNOWS_PEELED 04
   9
  10 struct ref_list {
  11         struct ref_list *next;
  12         unsigned char flag; /* ISSYMREF? ISPACKED? */
  13         unsigned char sha1[20];
  14         unsigned char peeled[20];
  15         char name[FLEX_ARRAY];
  16 };
  17
  18 static const char *parse_ref_line(char *line, unsigned char *sha1)
  19 {
  20         /*
  21          * 42: the answer to everything.
  22          *
  23          * In this case, it happens to be the answer to
  24          *  40 (length of sha1 hex representation)
  25          *  +1 (space in between hex and name)
  26          *  +1 (newline at the end of the line)
  27          */
  28         int len = strlen(line) - 42;
  29
  30         if (len <= 0)
  31                 return NULL;
  32         if (get_sha1_hex(line, sha1) < 0)
  33                 return NULL;
  34         if (!isspace(line[40]))
  35                 return NULL;
  36         line += 41;
  37         if (isspace(*line))
  38                 return NULL;
  39         if (line[len] != '\n')
  40                 return NULL;
  41         line[len] = 0;
  42
  43         return line;
  44 }
  45
  46 static struct ref_list *add_ref(const char *name, const unsigned char *sha1,
  47                                 int flag, struct ref_list *list,
  48                                 struct ref_list **new_entry)
  49 {
  50         int len;
  51         struct ref_list *entry;
  52
  53         /* Allocate it and add it in.. */
  54         len = strlen(name) + 1;
  55         entry = xmalloc(sizeof(struct ref_list) + len);
  56         hashcpy(entry->sha1, sha1);
  57         hashclr(entry->peeled);
  58         memcpy(entry->name, name, len);
  59         entry->flag = flag;
  60         entry->next = list;
  61         if (new_entry)
  62                 *new_entry = entry;
  63         return entry;
  64 }
  65
  66 /* merge sort the ref list */
  67 static struct ref_list *sort_ref_list(struct ref_list *list)
  68 {
  69         int psize, qsize, last_merge_count, cmp;
  70         struct ref_list *p, *q, *l, *e;
  71         struct ref_list *new_list = list;
  72         int k = 1;
  73         int merge_count = 0;
  74
  75         if (!list)
  76                 return list;
  77
  78         do {
  79                 last_merge_count = merge_count;
  80                 merge_count = 0;
  81
  82                 psize = 0;
  83
  84                 p = new_list;
  85                 q = new_list;
  86                 new_list = NULL;
  87                 l = NULL;
  88
  89                 while (p) {
  90                         merge_count++;
  91
  92                         while (psize < k && q->next) {
  93                                 q = q->next;
  94                                 psize++;
  95                         }
  96                         qsize = k;
  97
  98                         while ((psize > 0) || (qsize > 0 && q)) {
  99                                 if (qsize == 0 || !q) {
 100                                         e = p;
 101                                         p = p->next;
 102                                         psize--;
 103                                 } else if (psize == 0) {
 104                                         e = q;
 105                                         q = q->next;
 106                                         qsize--;
 107                                 } else {
 108                                         cmp = strcmp(q->name, p->name);
 109                                         if (cmp < 0) {
 110                                                 e = q;
 111                                                 q = q->next;
 112                                                 qsize--;
 113                                         } else if (cmp > 0) {
 114                                                 e = p;
 115                                                 p = p->next;
 116                                                 psize--;
 117                                         } else {
 118                                                 if (hashcmp(q->sha1, p->sha1))
 119                                                         die("Duplicated ref, and SHA1s don't match: %s",
 120                                                             q->name);
 121                                                 warning("Duplicated ref: %s", q->name);
 122                                                 e = q;
 123                                                 q = q->next;
 124                                                 qsize--;
 125                                                 free(e);
 126                                                 e = p;
 127                                                 p = p->next;
 128                                                 psize--;
 129                                         }
 130                                 }
 131
 132                                 e->next = NULL;
 133
 134                                 if (l)
 135                                         l->next = e;
 136                                 if (!new_list)
 137                                         new_list = e;
 138                                 l = e;
 139                         }
 140
 141                         p = q;
 142                 };
 143
 144                 k = k * 2;
 145         } while ((last_merge_count != merge_count) || (last_merge_count != 1));
 146
 147         return new_list;
 148 }
 149
 150 /*
 151  * Future: need to be in "struct repository"
 152  * when doing a full libification.
 153  */
 154 static struct cached_refs {
 155         char did_loose;
 156         char did_packed;
 157         struct ref_list *loose;
 158         struct ref_list *packed;
 159 } cached_refs;
 160 static struct ref_list *current_ref;
 161
 162 static struct ref_list *extra_refs;
 163
 164 static void free_ref_list(struct ref_list *list)
 165 {
 166         struct ref_list *next;
 167         for ( ; list; list = next) {
 168                 next = list->next;
 169                 free(list);
 170         }
 171 }
 172
 173 static void invalidate_cached_refs(void)
 174 {
 175         struct cached_refs *ca = &cached_refs;
 176
 177         if (ca->did_loose && ca->loose)
 178                 free_ref_list(ca->loose);
 179         if (ca->did_packed && ca->packed)
 180                 free_ref_list(ca->packed);
 181         ca->loose = ca->packed = NULL;
 182         ca->did_loose = ca->did_packed = 0;
 183 }
 184
 185 static void read_packed_refs(FILE *f, struct cached_refs *cached_refs)
 186 {
 187         struct ref_list *list = NULL;
 188         struct ref_list *last = NULL;
 189         char refline[PATH_MAX];
 190         int flag = REF_ISPACKED;
 191
 192         while (fgets(refline, sizeof(refline), f)) {
 193                 unsigned char sha1[20];
 194                 const char *name;
 195                 static const char header[] = "# pack-refs with:";
 196
 197                 if (!strncmp(refline, header, sizeof(header)-1)) {
 198                         const char *traits = refline + sizeof(header) - 1;
 199                         if (strstr(traits, " peeled "))
 200                                 flag |= REF_KNOWS_PEELED;
 201                         /* perhaps other traits later as well */
 202                         continue;
 203                 }
 204
 205                 name = parse_ref_line(refline, sha1);
 206                 if (name) {
 207                         list = add_ref(name, sha1, flag, list, &last);
 208                         continue;
 209                 }
 210                 if (last &&
 211                     refline[0] == '^' &&
 212                     strlen(refline) == 42 &&
 213                     refline[41] == '\n' &&
 214                     !get_sha1_hex(refline + 1, sha1))
 215                         hashcpy(last->peeled, sha1);
 216         }
 217         cached_refs->packed = sort_ref_list(list);
 218 }
 219
 220 void add_extra_ref(const char *name, const unsigned char *sha1, int flag)
 221 {
 222         extra_refs = add_ref(name, sha1, flag, extra_refs, NULL);
 223 }
 224
 225 void clear_extra_refs(void)
 226 {
 227         free_ref_list(extra_refs);
 228         extra_refs = NULL;
 229 }
 230
 231 static struct ref_list *get_packed_refs(void)
 232 {
 233         if (!cached_refs.did_packed) {
 234                 FILE *f = fopen(git_path("packed-refs"), "r");
 235                 cached_refs.packed = NULL;
 236                 if (f) {
 237                         read_packed_refs(f, &cached_refs);
 238                         fclose(f);
 239                 }
 240                 cached_refs.did_packed = 1;
 241         }
 242         return cached_refs.packed;
 243 }
 244
 245 static struct ref_list *get_ref_dir(const char *base, struct ref_list *list)
 246 {
 247         DIR *dir = opendir(git_path("%s", base));
 248
 249         if (dir) {
 250                 struct dirent *de;
 251                 int baselen = strlen(base);
 252                 char *ref = xmalloc(baselen + 257);
 253
 254                 memcpy(ref, base, baselen);
 255                 if (baselen && base[baselen-1] != '/')
 256                         ref[baselen++] = '/';
 257
 258                 while ((de = readdir(dir)) != NULL) {
 259                         unsigned char sha1[20];
 260                         struct stat st;
 261                         int flag;
 262                         int namelen;
 263
 264                         if (de->d_name[0] == '.')
 265                                 continue;
 266                         namelen = strlen(de->d_name);
 267                         if (namelen > 255)
 268                                 continue;
 269                         if (has_extension(de->d_name, ".lock"))
 270                                 continue;
 271                         memcpy(ref + baselen, de->d_name, namelen+1);
 272                         if (stat(git_path("%s", ref), &st) < 0)
 273                                 continue;
 274                         if (S_ISDIR(st.st_mode)) {
 275                                 list = get_ref_dir(ref, list);
 276                                 continue;
 277                         }
 278                         if (!resolve_ref(ref, sha1, 1, &flag))
 279                                 hashclr(sha1);
 280                         list = add_ref(ref, sha1, flag, list, NULL);
 281                 }
 282                 free(ref);
 283                 closedir(dir);
 284         }
 285         return sort_ref_list(list);
 286 }
 287
 288 struct warn_if_dangling_data {
 289         const char *refname;
 290         const char *msg_fmt;
 291 };
 292
 293 static int warn_if_dangling_symref(const char *refname, const unsigned char *sha1,
 294                                    int flags, void *cb_data)
 295 {
 296         struct warn_if_dangling_data *d = cb_data;
 297         const char *resolves_to;
 298         unsigned char junk[20];
 299
 300         if (!(flags & REF_ISSYMREF))
 301                 return 0;
 302
 303         resolves_to = resolve_ref(refname, junk, 0, NULL);
 304         if (!resolves_to || strcmp(resolves_to, d->refname))
 305                 return 0;
 306
 307         printf(d->msg_fmt, refname);
 308         return 0;
 309 }
 310
 311 void warn_dangling_symref(const char *msg_fmt, const char *refname)
 312 {
 313         struct warn_if_dangling_data data = { refname, msg_fmt };
 314         for_each_rawref(warn_if_dangling_symref, &data);
 315 }
 316
 317 static struct ref_list *get_loose_refs(void)
 318 {
 319         if (!cached_refs.did_loose) {
 320                 cached_refs.loose = get_ref_dir("refs", NULL);
 321                 cached_refs.did_loose = 1;
 322         }
 323         return cached_refs.loose;
 324 }
 325
 326 /* We allow "recursive" symbolic refs. Only within reason, though */
 327 #define MAXDEPTH 5
 328 #define MAXREFLEN (1024)
 329
 330 static int resolve_gitlink_packed_ref(char *name, int pathlen, const char *refname, unsigned char *result)
 331 {
 332         FILE *f;
 333         struct cached_refs refs;
 334         struct ref_list *ref;
 335         int retval;
 336
 337         strcpy(name + pathlen, "packed-refs");
 338         f = fopen(name, "r");
 339         if (!f)
 340                 return -1;
 341         read_packed_refs(f, &refs);
 342         fclose(f);
 343         ref = refs.packed;
 344         retval = -1;
 345         while (ref) {
 346                 if (!strcmp(ref->name, refname)) {
 347                         retval = 0;
 348                         memcpy(result, ref->sha1, 20);
 349                         break;
 350                 }
 351                 ref = ref->next;
 352         }
 353         free_ref_list(refs.packed);
 354         return retval;
 355 }
 356
 357 static int resolve_gitlink_ref_recursive(char *name, int pathlen, const char *refname, unsigned char *result, int recursion)
 358 {
 359         int fd, len = strlen(refname);
 360         char buffer[128], *p;
 361
 362         if (recursion > MAXDEPTH || len > MAXREFLEN)
 363                 return -1;
 364         memcpy(name + pathlen, refname, len+1);
 365         fd = open(name, O_RDONLY);
 366         if (fd < 0)
 367                 return resolve_gitlink_packed_ref(name, pathlen, refname, result);
 368
 369         len = read(fd, buffer, sizeof(buffer)-1);
 370         close(fd);
 371         if (len < 0)
 372                 return -1;
 373         while (len && isspace(buffer[len-1]))
 374                 len--;
 375         buffer[len] = 0;
 376
 377         /* Was it a detached head or an old-fashioned symlink? */
 378         if (!get_sha1_hex(buffer, result))
 379                 return 0;
 380
 381         /* Symref? */
 382         if (strncmp(buffer, "ref:", 4))
 383                 return -1;
 384         p = buffer + 4;
 385         while (isspace(*p))
 386                 p++;
 387
 388         return resolve_gitlink_ref_recursive(name, pathlen, p, result, recursion+1);
 389 }
 390
 391 int resolve_gitlink_ref(const char *path, const char *refname, unsigned char *result)
 392 {
 393         int len = strlen(path), retval;
 394         char *gitdir;
 395         const char *tmp;
 396
 397         while (len && path[len-1] == '/')
 398                 len--;
 399         if (!len)
 400                 return -1;
 401         gitdir = xmalloc(len + MAXREFLEN + 8);
 402         memcpy(gitdir, path, len);
 403         memcpy(gitdir + len, "/.git", 6);
 404         len += 5;
 405
 406         tmp = read_gitfile_gently(gitdir);
 407         if (tmp) {
 408                 free(gitdir);
 409                 len = strlen(tmp);
 410                 gitdir = xmalloc(len + MAXREFLEN + 3);
 411                 memcpy(gitdir, tmp, len);
 412         }
 413         gitdir[len] = '/';
 414         gitdir[++len] = '\0';
 415         retval = resolve_gitlink_ref_recursive(gitdir, len, refname, result, 0);
 416         free(gitdir);
 417         return retval;
 418 }
 419
 420 /*
 421  * If the "reading" argument is set, this function finds out what _object_
 422  * the ref points at by "reading" the ref.  The ref, if it is not symbolic,
 423  * has to exist, and if it is symbolic, it has to point at an existing ref,
 424  * because the "read" goes through the symref to the ref it points at.
 425  *
 426  * The access that is not "reading" may often be "writing", but does not
 427  * have to; it can be merely checking _where it leads to_. If it is a
 428  * prelude to "writing" to the ref, a write to a symref that points at
 429  * yet-to-be-born ref will create the real ref pointed by the symref.
 430  * reading=0 allows the caller to check where such a symref leads to.
 431  */
 432 const char *resolve_ref(const char *ref, unsigned char *sha1, int reading, int *flag)
 433 {
 434         int depth = MAXDEPTH;
 435         ssize_t len;
 436         char buffer[256];
 437         static char ref_buffer[256];
 438
 439         if (flag)
 440                 *flag = 0;
 441
 442         for (;;) {
 443                 char path[PATH_MAX];
 444                 struct stat st;
 445                 char *buf;
 446                 int fd;
 447
 448                 if (--depth < 0)
 449                         return NULL;
 450
 451                 git_snpath(path, sizeof(path), "%s", ref);
 452                 /* Special case: non-existing file. */
 453                 if (lstat(path, &st) < 0) {
 454                         struct ref_list *list = get_packed_refs();
 455                         while (list) {
 456                                 if (!strcmp(ref, list->name)) {
 457                                         hashcpy(sha1, list->sha1);
 458                                         if (flag)
 459                                                 *flag |= REF_ISPACKED;
 460                                         return ref;
 461                                 }
 462                                 list = list->next;
 463                         }
 464                         if (reading || errno != ENOENT)
 465                                 return NULL;
 466                         hashclr(sha1);
 467                         return ref;
 468                 }
 469
 470                 /* Follow "normalized" - ie "refs/.." symlinks by hand */
 471                 if (S_ISLNK(st.st_mode)) {
 472                         len = readlink(path, buffer, sizeof(buffer)-1);
 473                         if (len >= 5 && !memcmp("refs/", buffer, 5)) {
 474                                 buffer[len] = 0;
 475                                 strcpy(ref_buffer, buffer);
 476                                 ref = ref_buffer;
 477                                 if (flag)
 478                                         *flag |= REF_ISSYMREF;
 479                                 continue;
 480                         }
 481                 }
 482
 483                 /* Is it a directory? */
 484                 if (S_ISDIR(st.st_mode)) {
 485                         errno = EISDIR;
 486                         return NULL;
 487                 }
 488
 489                 /*
 490                  * Anything else, just open it and try to use it as
 491                  * a ref
 492                  */
 493                 fd = open(path, O_RDONLY);
 494                 if (fd < 0)
 495                         return NULL;
 496                 len = read_in_full(fd, buffer, sizeof(buffer)-1);
 497                 close(fd);
 498
 499                 /*
 500                  * Is it a symbolic ref?
 501                  */
 502                 if (len < 4 || memcmp("ref:", buffer, 4))
 503                         break;
 504                 buf = buffer + 4;
 505                 len -= 4;
 506                 while (len && isspace(*buf))
 507                         buf++, len--;
 508                 while (len && isspace(buf[len-1]))
 509                         len--;
 510                 buf[len] = 0;
 511                 memcpy(ref_buffer, buf, len + 1);
 512                 ref = ref_buffer;
 513                 if (flag)
 514                         *flag |= REF_ISSYMREF;
 515         }
 516         if (len < 40 || get_sha1_hex(buffer, sha1))
 517                 return NULL;
 518         return ref;
 519 }
 520
 521 int read_ref(const char *ref, unsigned char *sha1)
 522 {
 523         if (resolve_ref(ref, sha1, 1, NULL))
 524                 return 0;
 525         return -1;
 526 }
 527
 528 #define DO_FOR_EACH_INCLUDE_BROKEN 01
 529 static int do_one_ref(const char *base, each_ref_fn fn, int trim,
 530                       int flags, void *cb_data, struct ref_list *entry)
 531 {
 532         if (strncmp(base, entry->name, trim))
 533                 return 0;
 534         if (!(flags & DO_FOR_EACH_INCLUDE_BROKEN)) {
 535                 if (is_null_sha1(entry->sha1))
 536                         return 0;
 537                 if (!has_sha1_file(entry->sha1)) {
 538                         error("%s does not point to a valid object!", entry->name);
 539                         return 0;
 540                 }
 541         }
 542         current_ref = entry;
 543         return fn(entry->name + trim, entry->sha1, entry->flag, cb_data);
 544 }
 545
 546 int peel_ref(const char *ref, unsigned char *sha1)
 547 {
 548         int flag;
 549         unsigned char base[20];
 550         struct object *o;
 551
 552         if (current_ref && (current_ref->name == ref
 553                 || !strcmp(current_ref->name, ref))) {
 554                 if (current_ref->flag & REF_KNOWS_PEELED) {
 555                         hashcpy(sha1, current_ref->peeled);
 556                         return 0;
 557                 }
 558                 hashcpy(base, current_ref->sha1);
 559                 goto fallback;
 560         }
 561
 562         if (!resolve_ref(ref, base, 1, &flag))
 563                 return -1;
 564
 565         if ((flag & REF_ISPACKED)) {
 566                 struct ref_list *list = get_packed_refs();
 567
 568                 while (list) {
 569                         if (!strcmp(list->name, ref)) {
 570                                 if (list->flag & REF_KNOWS_PEELED) {
 571                                         hashcpy(sha1, list->peeled);
 572                                         return 0;
 573                                 }
 574                                 /* older pack-refs did not leave peeled ones */
 575                                 break;
 576                         }
 577                         list = list->next;
 578                 }
 579         }
 580
 581 fallback:
 582         o = parse_object(base);
 583         if (o && o->type == OBJ_TAG) {
 584                 o = deref_tag(o, ref, 0);
 585                 if (o) {
 586                         hashcpy(sha1, o->sha1);
 587                         return 0;
 588                 }
 589         }
 590         return -1;
 591 }
 592
 593 static int do_for_each_ref(const char *base, each_ref_fn fn, int trim,
 594                            int flags, void *cb_data)
 595 {
 596         int retval = 0;
 597         struct ref_list *packed = get_packed_refs();
 598         struct ref_list *loose = get_loose_refs();
 599
 600         struct ref_list *extra;
 601
 602         for (extra = extra_refs; extra; extra = extra->next)
 603                 retval = do_one_ref(base, fn, trim, flags, cb_data, extra);
 604
 605         while (packed && loose) {
 606                 struct ref_list *entry;
 607                 int cmp = strcmp(packed->name, loose->name);
 608                 if (!cmp) {
 609                         packed = packed->next;
 610                         continue;
 611                 }
 612                 if (cmp > 0) {
 613                         entry = loose;
 614                         loose = loose->next;
 615                 } else {
 616                         entry = packed;
 617                         packed = packed->next;
 618                 }
 619                 retval = do_one_ref(base, fn, trim, flags, cb_data, entry);
 620                 if (retval)
 621                         goto end_each;
 622         }
 623
 624         for (packed = packed ? packed : loose; packed; packed = packed->next) {
 625                 retval = do_one_ref(base, fn, trim, flags, cb_data, packed);
 626                 if (retval)
 627                         goto end_each;
 628         }
 629
 630 end_each:
 631         current_ref = NULL;
 632         return retval;
 633 }
 634
 635 int head_ref(each_ref_fn fn, void *cb_data)
 636 {
 637         unsigned char sha1[20];
 638         int flag;
 639
 640         if (resolve_ref("HEAD", sha1, 1, &flag))
 641                 return fn("HEAD", sha1, flag, cb_data);
 642         return 0;
 643 }
 644
 645 int for_each_ref(each_ref_fn fn, void *cb_data)
 646 {
 647         return do_for_each_ref("refs/", fn, 0, 0, cb_data);
 648 }
 649
 650 int for_each_tag_ref(each_ref_fn fn, void *cb_data)
 651 {
 652         return do_for_each_ref("refs/tags/", fn, 10, 0, cb_data);
 653 }
 654
 655 int for_each_branch_ref(each_ref_fn fn, void *cb_data)
 656 {
 657         return do_for_each_ref("refs/heads/", fn, 11, 0, cb_data);
 658 }
 659
 660 int for_each_remote_ref(each_ref_fn fn, void *cb_data)
 661 {
 662         return do_for_each_ref("refs/remotes/", fn, 13, 0, cb_data);
 663 }
 664
 665 int for_each_rawref(each_ref_fn fn, void *cb_data)
 666 {
 667         return do_for_each_ref("refs/", fn, 0,
 668                                DO_FOR_EACH_INCLUDE_BROKEN, cb_data);
 669 }
 670
 671 /*
 672  * Make sure "ref" is something reasonable to have under ".git/refs/";
 673  * We do not like it if:
 674  *
 675  * - any path component of it begins with ".", or
 676  * - it has double dots "..", or
 677  * - it has ASCII control character, "~", "^", ":" or SP, anywhere, or
 678  * - it ends with a "/".
 679  */
 680
 681 static inline int bad_ref_char(int ch)
 682 {
 683         if (((unsigned) ch) <= ' ' ||
 684             ch == '~' || ch == '^' || ch == ':')
 685                 return 1;
 686         /* 2.13 Pattern Matching Notation */
 687         if (ch == '?' || ch == '[') /* Unsupported */
 688                 return 1;
 689         if (ch == '*') /* Supported at the end */
 690                 return 2;
 691         return 0;
 692 }
 693
 694 int check_ref_format(const char *ref)
 695 {
 696         int ch, level, bad_type, last;
 697         int ret = CHECK_REF_FORMAT_OK;
 698         const char *cp = ref;
 699
 700         level = 0;
 701         while (1) {
 702                 while ((ch = *cp++) == '/')
 703                         ; /* tolerate duplicated slashes */
 704                 if (!ch)
 705                         /* should not end with slashes */
 706                         return CHECK_REF_FORMAT_ERROR;
 707
 708                 /* we are at the beginning of the path component */
 709                 if (ch == '.')
 710                         return CHECK_REF_FORMAT_ERROR;
 711                 bad_type = bad_ref_char(ch);
 712                 if (bad_type) {
 713                         if (bad_type == 2 && (!*cp || *cp == '/') &&
 714                             ret == CHECK_REF_FORMAT_OK)
 715                                 ret = CHECK_REF_FORMAT_WILDCARD;
 716                         else
 717                                 return CHECK_REF_FORMAT_ERROR;
 718                 }
 719
 720                 last = ch;
 721                 /* scan the rest of the path component */
 722                 while ((ch = *cp++) != 0) {
 723                         bad_type = bad_ref_char(ch);
 724                         if (bad_type)
 725                                 return CHECK_REF_FORMAT_ERROR;
 726                         if (ch == '/')
 727                                 break;
 728                         if (last == '.' && ch == '.')
 729                                 return CHECK_REF_FORMAT_ERROR;
 730                         if (last == '@' && ch == '{')
 731                                 return CHECK_REF_FORMAT_ERROR;
 732                         last = ch;
 733                 }
 734                 level++;
 735                 if (!ch) {
 736                         if (ref <= cp - 2 && cp[-2] == '.')
 737                                 return CHECK_REF_FORMAT_ERROR;
 738                         if (level < 2)
 739                                 return CHECK_REF_FORMAT_ONELEVEL;
 740                         return ret;
 741                 }
 742         }
 743 }
 744
 745 const char *ref_rev_parse_rules[] = {
 746         "%.*s",
 747         "refs/%.*s",
 748         "refs/tags/%.*s",
 749         "refs/heads/%.*s",
 750         "refs/remotes/%.*s",
 751         "refs/remotes/%.*s/HEAD",
 752         NULL
 753 };
 754
 755 const char *ref_fetch_rules[] = {
 756         "%.*s",
 757         "refs/%.*s",
 758         "refs/heads/%.*s",
 759         NULL
 760 };
 761
 762 int refname_match(const char *abbrev_name, const char *full_name, const char **rules)
 763 {
 764         const char **p;
 765         const int abbrev_name_len = strlen(abbrev_name);
 766
 767         for (p = rules; *p; p++) {
 768                 if (!strcmp(full_name, mkpath(*p, abbrev_name_len, abbrev_name))) {
 769                         return 1;
 770                 }
 771         }
 772
 773         return 0;
 774 }
 775
 776 static struct ref_lock *verify_lock(struct ref_lock *lock,
 777         const unsigned char *old_sha1, int mustexist)
 778 {
 779         if (!resolve_ref(lock->ref_name, lock->old_sha1, mustexist, NULL)) {
 780                 error("Can't verify ref %s", lock->ref_name);
 781                 unlock_ref(lock);
 782                 return NULL;
 783         }
 784         if (hashcmp(lock->old_sha1, old_sha1)) {
 785                 error("Ref %s is at %s but expected %s", lock->ref_name,
 786                         sha1_to_hex(lock->old_sha1), sha1_to_hex(old_sha1));
 787                 unlock_ref(lock);
 788                 return NULL;
 789         }
 790         return lock;
 791 }
 792
 793 static int remove_empty_directories(const char *file)
 794 {
 795         /* we want to create a file but there is a directory there;
 796          * if that is an empty directory (or a directory that contains
 797          * only empty directories), remove them.
 798          */
 799         struct strbuf path;
 800         int result;
 801
 802         strbuf_init(&path, 20);
 803         strbuf_addstr(&path, file);
 804
 805         result = remove_dir_recursively(&path, 1);
 806
 807         strbuf_release(&path);
 808
 809         return result;
 810 }
 811
 812 static int is_refname_available(const char *ref, const char *oldref,
 813                                 struct ref_list *list, int quiet)
 814 {
 815         int namlen = strlen(ref); /* e.g. 'foo/bar' */
 816         while (list) {
 817                 /* list->name could be 'foo' or 'foo/bar/baz' */
 818                 if (!oldref || strcmp(oldref, list->name)) {
 819                         int len = strlen(list->name);
 820                         int cmplen = (namlen < len) ? namlen : len;
 821                         const char *lead = (namlen < len) ? list->name : ref;
 822                         if (!strncmp(ref, list->name, cmplen) &&
 823                             lead[cmplen] == '/') {
 824                                 if (!quiet)
 825                                         error("'%s' exists; cannot create '%s'",
 826                                               list->name, ref);
 827                                 return 0;
 828                         }
 829                 }
 830                 list = list->next;
 831         }
 832         return 1;
 833 }
 834
 835 static struct ref_lock *lock_ref_sha1_basic(const char *ref, const unsigned char *old_sha1, int flags, int *type_p)
 836 {
 837         char *ref_file;
 838         const char *orig_ref = ref;
 839         struct ref_lock *lock;
 840         int last_errno = 0;
 841         int type, lflags;
 842         int mustexist = (old_sha1 && !is_null_sha1(old_sha1));
 843         int missing = 0;
 844
 845         lock = xcalloc(1, sizeof(struct ref_lock));
 846         lock->lock_fd = -1;
 847
 848         ref = resolve_ref(ref, lock->old_sha1, mustexist, &type);
 849         if (!ref && errno == EISDIR) {
 850                 /* we are trying to lock foo but we used to
 851                  * have foo/bar which now does not exist;
 852                  * it is normal for the empty directory 'foo'
 853                  * to remain.
 854                  */
 855                 ref_file = git_path("%s", orig_ref);
 856                 if (remove_empty_directories(ref_file)) {
 857                         last_errno = errno;
 858                         error("there are still refs under '%s'", orig_ref);
 859                         goto error_return;
 860                 }
 861                 ref = resolve_ref(orig_ref, lock->old_sha1, mustexist, &type);
 862         }
 863         if (type_p)
 864             *type_p = type;
 865         if (!ref) {
 866                 last_errno = errno;
 867                 error("unable to resolve reference %s: %s",
 868                         orig_ref, strerror(errno));
 869                 goto error_return;
 870         }
 871         missing = is_null_sha1(lock->old_sha1);
 872         /* When the ref did not exist and we are creating it,
 873          * make sure there is no existing ref that is packed
 874          * whose name begins with our refname, nor a ref whose
 875          * name is a proper prefix of our refname.
 876          */
 877         if (missing &&
 878             !is_refname_available(ref, NULL, get_packed_refs(), 0))
 879                 goto error_return;
 880
 881         lock->lk = xcalloc(1, sizeof(struct lock_file));
 882
 883         lflags = LOCK_DIE_ON_ERROR;
 884         if (flags & REF_NODEREF) {
 885                 ref = orig_ref;
 886                 lflags |= LOCK_NODEREF;
 887         }
 888         lock->ref_name = xstrdup(ref);
 889         lock->orig_ref_name = xstrdup(orig_ref);
 890         ref_file = git_path("%s", ref);
 891         if (missing)
 892                 lock->force_write = 1;
 893         if ((flags & REF_NODEREF) && (type & REF_ISSYMREF))
 894                 lock->force_write = 1;
 895
 896         if (safe_create_leading_directories(ref_file)) {
 897                 last_errno = errno;
 898                 error("unable to create directory for %s", ref_file);
 899                 goto error_return;
 900         }
 901
 902         lock->lock_fd = hold_lock_file_for_update(lock->lk, ref_file, lflags);
 903         return old_sha1 ? verify_lock(lock, old_sha1, mustexist) : lock;
 904
 905  error_return:
 906         unlock_ref(lock);
 907         errno = last_errno;
 908         return NULL;
 909 }
 910
 911 struct ref_lock *lock_ref_sha1(const char *ref, const unsigned char *old_sha1)
 912 {
 913         char refpath[PATH_MAX];
 914         if (check_ref_format(ref))
 915                 return NULL;
 916         strcpy(refpath, mkpath("refs/%s", ref));
 917         return lock_ref_sha1_basic(refpath, old_sha1, 0, NULL);
 918 }
 919
 920 struct ref_lock *lock_any_ref_for_update(const char *ref, const unsigned char *old_sha1, int flags)
 921 {
 922         switch (check_ref_format(ref)) {
 923         default:
 924                 return NULL;
 925         case 0:
 926         case CHECK_REF_FORMAT_ONELEVEL:
 927                 return lock_ref_sha1_basic(ref, old_sha1, flags, NULL);
 928         }
 929 }
 930
 931 static struct lock_file packlock;
 932
 933 static int repack_without_ref(const char *refname)
 934 {
 935         struct ref_list *list, *packed_ref_list;
 936         int fd;
 937         int found = 0;
 938
 939         packed_ref_list = get_packed_refs();
 940         for (list = packed_ref_list; list; list = list->next) {
 941                 if (!strcmp(refname, list->name)) {
 942                         found = 1;
 943                         break;
 944                 }
 945         }
 946         if (!found)
 947                 return 0;
 948         fd = hold_lock_file_for_update(&packlock, git_path("packed-refs"), 0);
 949         if (fd < 0)
 950                 return error("cannot delete '%s' from packed refs", refname);
 951
 952         for (list = packed_ref_list; list; list = list->next) {
 953                 char line[PATH_MAX + 100];
 954                 int len;
 955
 956                 if (!strcmp(refname, list->name))
 957                         continue;
 958                 len = snprintf(line, sizeof(line), "%s %s\n",
 959                                sha1_to_hex(list->sha1), list->name);
 960                 /* this should not happen but just being defensive */
 961                 if (len > sizeof(line))
 962                         die("too long a refname '%s'", list->name);
 963                 write_or_die(fd, line, len);
 964         }
 965         return commit_lock_file(&packlock);
 966 }
 967
 968 int delete_ref(const char *refname, const unsigned char *sha1, int delopt)
 969 {
 970         struct ref_lock *lock;
 971         int err, i = 0, ret = 0, flag = 0;
 972
 973         lock = lock_ref_sha1_basic(refname, sha1, 0, &flag);
 974         if (!lock)
 975                 return 1;
 976         if (!(flag & REF_ISPACKED) || flag & REF_ISSYMREF) {
 977                 /* loose */
 978                 const char *path;
 979
 980                 if (!(delopt & REF_NODEREF)) {
 981                         i = strlen(lock->lk->filename) - 5; /* .lock */
 982                         lock->lk->filename[i] = 0;
 983                         path = lock->lk->filename;
 984                 } else {
 985                         path = git_path("%s", refname);
 986                 }
 987                 err = unlink(path);
 988                 if (err && errno != ENOENT) {
 989                         ret = 1;
 990                         error("unlink(%s) failed: %s",
 991                               path, strerror(errno));
 992                 }
 993                 if (!(delopt & REF_NODEREF))
 994                         lock->lk->filename[i] = '.';
 995         }
 996         /* removing the loose one could have resurrected an earlier
 997          * packed one.  Also, if it was not loose we need to repack
 998          * without it.
 999          */
1000         ret |= repack_without_ref(refname);
1001
1002         err = unlink(git_path("logs/%s", lock->ref_name));
1003         if (err && errno != ENOENT)
1004                 fprintf(stderr, "warning: unlink(%s) failed: %s",
1005                         git_path("logs/%s", lock->ref_name), strerror(errno));
1006         invalidate_cached_refs();
1007         unlock_ref(lock);
1008         return ret;
1009 }
1010
1011 int rename_ref(const char *oldref, const char *newref, const char *logmsg)
1012 {
1013         static const char renamed_ref[] = "RENAMED-REF";
1014         unsigned char sha1[20], orig_sha1[20];
1015         int flag = 0, logmoved = 0;
1016         struct ref_lock *lock;
1017         struct stat loginfo;
1018         int log = !lstat(git_path("logs/%s", oldref), &loginfo);
1019         const char *symref = NULL;
1020
1021         if (log && S_ISLNK(loginfo.st_mode))
1022                 return error("reflog for %s is a symlink", oldref);
1023
1024         symref = resolve_ref(oldref, orig_sha1, 1, &flag);
1025         if (flag & REF_ISSYMREF)
1026                 return error("refname %s is a symbolic ref, renaming it is not supported",
1027                         oldref);
1028         if (!symref)
1029                 return error("refname %s not found", oldref);
1030
1031         if (!is_refname_available(newref, oldref, get_packed_refs(), 0))
1032                 return 1;
1033
1034         if (!is_refname_available(newref, oldref, get_loose_refs(), 0))
1035                 return 1;
1036
1037         lock = lock_ref_sha1_basic(renamed_ref, NULL, 0, NULL);
1038         if (!lock)
1039                 return error("unable to lock %s", renamed_ref);
1040         lock->force_write = 1;
1041         if (write_ref_sha1(lock, orig_sha1, logmsg))
1042                 return error("unable to save current sha1 in %s", renamed_ref);
1043
1044         if (log && rename(git_path("logs/%s", oldref), git_path("tmp-renamed-log")))
1045                 return error("unable to move logfile logs/%s to tmp-renamed-log: %s",
1046                         oldref, strerror(errno));
1047
1048         if (delete_ref(oldref, orig_sha1, REF_NODEREF)) {
1049                 error("unable to delete old %s", oldref);
1050                 goto rollback;
1051         }
1052
1053         if (resolve_ref(newref, sha1, 1, &flag) && delete_ref(newref, sha1, REF_NODEREF)) {
1054                 if (errno==EISDIR) {
1055                         if (remove_empty_directories(git_path("%s", newref))) {
1056                                 error("Directory not empty: %s", newref);
1057                                 goto rollback;
1058                         }
1059                 } else {
1060                         error("unable to delete existing %s", newref);
1061                         goto rollback;
1062                 }
1063         }
1064
1065         if (log && safe_create_leading_directories(git_path("logs/%s", newref))) {
1066                 error("unable to create directory for %s", newref);
1067                 goto rollback;
1068         }
1069
1070  retry:
1071         if (log && rename(git_path("tmp-renamed-log"), git_path("logs/%s", newref))) {
1072                 if (errno==EISDIR || errno==ENOTDIR) {
1073                         /*
1074                          * rename(a, b) when b is an existing
1075                          * directory ought to result in ISDIR, but
1076                          * Solaris 5.8 gives ENOTDIR.  Sheesh.
1077                          */
1078                         if (remove_empty_directories(git_path("logs/%s", newref))) {
1079                                 error("Directory not empty: logs/%s", newref);
1080                                 goto rollback;
1081                         }
1082                         goto retry;
1083                 } else {
1084                         error("unable to move logfile tmp-renamed-log to logs/%s: %s",
1085                                 newref, strerror(errno));
1086                         goto rollback;
1087                 }
1088         }
1089         logmoved = log;
1090
1091         lock = lock_ref_sha1_basic(newref, NULL, 0, NULL);
1092         if (!lock) {
1093                 error("unable to lock %s for update", newref);
1094                 goto rollback;
1095         }
1096         lock->force_write = 1;
1097         hashcpy(lock->old_sha1, orig_sha1);
1098         if (write_ref_sha1(lock, orig_sha1, logmsg)) {
1099                 error("unable to write current sha1 into %s", newref);
1100                 goto rollback;
1101         }
1102
1103         return 0;
1104
1105  rollback:
1106         lock = lock_ref_sha1_basic(oldref, NULL, 0, NULL);
1107         if (!lock) {
1108                 error("unable to lock %s for rollback", oldref);
1109                 goto rollbacklog;
1110         }
1111
1112         lock->force_write = 1;
1113         flag = log_all_ref_updates;
1114         log_all_ref_updates = 0;
1115         if (write_ref_sha1(lock, orig_sha1, NULL))
1116                 error("unable to write current sha1 into %s", oldref);
1117         log_all_ref_updates = flag;
1118
1119  rollbacklog:
1120         if (logmoved && rename(git_path("logs/%s", newref), git_path("logs/%s", oldref)))
1121                 error("unable to restore logfile %s from %s: %s",
1122                         oldref, newref, strerror(errno));
1123         if (!logmoved && log &&
1124             rename(git_path("tmp-renamed-log"), git_path("logs/%s", oldref)))
1125                 error("unable to restore logfile %s from tmp-renamed-log: %s",
1126                         oldref, strerror(errno));
1127
1128         return 1;
1129 }
1130
1131 int close_ref(struct ref_lock *lock)
1132 {
1133         if (close_lock_file(lock->lk))
1134                 return -1;
1135         lock->lock_fd = -1;
1136         return 0;
1137 }
1138
1139 int commit_ref(struct ref_lock *lock)
1140 {
1141         if (commit_lock_file(lock->lk))
1142                 return -1;
1143         lock->lock_fd = -1;
1144         return 0;
1145 }
1146
1147 void unlock_ref(struct ref_lock *lock)
1148 {
1149         /* Do not free lock->lk -- atexit() still looks at them */
1150         if (lock->lk)
1151                 rollback_lock_file(lock->lk);
1152         free(lock->ref_name);
1153         free(lock->orig_ref_name);
1154         free(lock);
1155 }
1156
1157 /*
1158  * copy the reflog message msg to buf, which has been allocated sufficiently
1159  * large, while cleaning up the whitespaces.  Especially, convert LF to space,
1160  * because reflog file is one line per entry.
1161  */
1162 static int copy_msg(char *buf, const char *msg)
1163 {
1164         char *cp = buf;
1165         char c;
1166         int wasspace = 1;
1167
1168         *cp++ = '\t';
1169         while ((c = *msg++)) {
1170                 if (wasspace && isspace(c))
1171                         continue;
1172                 wasspace = isspace(c);
1173                 if (wasspace)
1174                         c = ' ';
1175                 *cp++ = c;
1176         }
1177         while (buf < cp && isspace(cp[-1]))
1178                 cp--;
1179         *cp++ = '\n';
1180         return cp - buf;
1181 }
1182
1183 static int log_ref_write(const char *ref_name, const unsigned char *old_sha1,
1184                          const unsigned char *new_sha1, const char *msg)
1185 {
1186         int logfd, written, oflags = O_APPEND | O_WRONLY;
1187         unsigned maxlen, len;
1188         int msglen;
1189         char log_file[PATH_MAX];
1190         char *logrec;
1191         const char *committer;
1192
1193         if (log_all_ref_updates < 0)
1194                 log_all_ref_updates = !is_bare_repository();
1195
1196         git_snpath(log_file, sizeof(log_file), "logs/%s", ref_name);
1197
1198         if (log_all_ref_updates &&
1199             (!prefixcmp(ref_name, "refs/heads/") ||
1200              !prefixcmp(ref_name, "refs/remotes/") ||
1201              !strcmp(ref_name, "HEAD"))) {
1202                 if (safe_create_leading_directories(log_file) < 0)
1203                         return error("unable to create directory for %s",
1204                                      log_file);
1205                 oflags |= O_CREAT;
1206         }
1207
1208         logfd = open(log_file, oflags, 0666);
1209         if (logfd < 0) {
1210                 if (!(oflags & O_CREAT) && errno == ENOENT)
1211                         return 0;
1212
1213                 if ((oflags & O_CREAT) && errno == EISDIR) {
1214                         if (remove_empty_directories(log_file)) {
1215                                 return error("There are still logs under '%s'",
1216                                              log_file);
1217                         }
1218                         logfd = open(log_file, oflags, 0666);
1219                 }
1220
1221                 if (logfd < 0)
1222                         return error("Unable to append to %s: %s",
1223                                      log_file, strerror(errno));
1224         }
1225
1226         adjust_shared_perm(log_file);
1227
1228         msglen = msg ? strlen(msg) : 0;
1229         committer = git_committer_info(0);
1230         maxlen = strlen(committer) + msglen + 100;
1231         logrec = xmalloc(maxlen);
1232         len = sprintf(logrec, "%s %s %s\n",
1233                       sha1_to_hex(old_sha1),
1234                       sha1_to_hex(new_sha1),
1235                       committer);
1236         if (msglen)
1237                 len += copy_msg(logrec + len - 1, msg) - 1;
1238         written = len <= maxlen ? write_in_full(logfd, logrec, len) : -1;
1239         free(logrec);
1240         if (close(logfd) != 0 || written != len)
1241                 return error("Unable to append to %s", log_file);
1242         return 0;
1243 }
1244
1245 static int is_branch(const char *refname)
1246 {
1247         return !strcmp(refname, "HEAD") || !prefixcmp(refname, "refs/heads/");
1248 }
1249
1250 int write_ref_sha1(struct ref_lock *lock,
1251         const unsigned char *sha1, const char *logmsg)
1252 {
1253         static char term = '\n';
1254         struct object *o;
1255
1256         if (!lock)
1257                 return -1;
1258         if (!lock->force_write && !hashcmp(lock->old_sha1, sha1)) {
1259                 unlock_ref(lock);
1260                 return 0;
1261         }
1262         o = parse_object(sha1);
1263         if (!o) {
1264                 error("Trying to write ref %s with nonexistant object %s",
1265                         lock->ref_name, sha1_to_hex(sha1));
1266                 unlock_ref(lock);
1267                 return -1;
1268         }
1269         if (o->type != OBJ_COMMIT && is_branch(lock->ref_name)) {
1270                 error("Trying to write non-commit object %s to branch %s",
1271                         sha1_to_hex(sha1), lock->ref_name);
1272                 unlock_ref(lock);
1273                 return -1;
1274         }
1275         if (write_in_full(lock->lock_fd, sha1_to_hex(sha1), 40) != 40 ||
1276             write_in_full(lock->lock_fd, &term, 1) != 1
1277                 || close_ref(lock) < 0) {
1278                 error("Couldn't write %s", lock->lk->filename);
1279                 unlock_ref(lock);
1280                 return -1;
1281         }
1282         invalidate_cached_refs();
1283         if (log_ref_write(lock->ref_name, lock->old_sha1, sha1, logmsg) < 0 ||
1284             (strcmp(lock->ref_name, lock->orig_ref_name) &&
1285              log_ref_write(lock->orig_ref_name, lock->old_sha1, sha1, logmsg) < 0)) {
1286                 unlock_ref(lock);
1287                 return -1;
1288         }
1289         if (strcmp(lock->orig_ref_name, "HEAD") != 0) {
1290                 /*
1291                  * Special hack: If a branch is updated directly and HEAD
1292                  * points to it (may happen on the remote side of a push
1293                  * for example) then logically the HEAD reflog should be
1294                  * updated too.
1295                  * A generic solution implies reverse symref information,
1296                  * but finding all symrefs pointing to the given branch
1297                  * would be rather costly for this rare event (the direct
1298                  * update of a branch) to be worth it.  So let's cheat and
1299                  * check with HEAD only which should cover 99% of all usage
1300                  * scenarios (even 100% of the default ones).
1301                  */
1302                 unsigned char head_sha1[20];
1303                 int head_flag;
1304                 const char *head_ref;
1305                 head_ref = resolve_ref("HEAD", head_sha1, 1, &head_flag);
1306                 if (head_ref && (head_flag & REF_ISSYMREF) &&
1307                     !strcmp(head_ref, lock->ref_name))
1308                         log_ref_write("HEAD", lock->old_sha1, sha1, logmsg);
1309         }
1310         if (commit_ref(lock)) {
1311                 error("Couldn't set %s", lock->ref_name);
1312                 unlock_ref(lock);
1313                 return -1;
1314         }
1315         unlock_ref(lock);
1316         return 0;
1317 }
1318
1319 int create_symref(const char *ref_target, const char *refs_heads_master,
1320                   const char *logmsg)
1321 {
1322         const char *lockpath;
1323         char ref[1000];
1324         int fd, len, written;
1325         char *git_HEAD = git_pathdup("%s", ref_target);
1326         unsigned char old_sha1[20], new_sha1[20];
1327
1328         if (logmsg && read_ref(ref_target, old_sha1))
1329                 hashclr(old_sha1);
1330
1331         if (safe_create_leading_directories(git_HEAD) < 0)
1332                 return error("unable to create directory for %s", git_HEAD);
1333
1334 #ifndef NO_SYMLINK_HEAD
1335         if (prefer_symlink_refs) {
1336                 unlink(git_HEAD);
1337                 if (!symlink(refs_heads_master, git_HEAD))
1338                         goto done;
1339                 fprintf(stderr, "no symlink - falling back to symbolic ref\n");
1340         }
1341 #endif
1342
1343         len = snprintf(ref, sizeof(ref), "ref: %s\n", refs_heads_master);
1344         if (sizeof(ref) <= len) {
1345                 error("refname too long: %s", refs_heads_master);
1346                 goto error_free_return;
1347         }
1348         lockpath = mkpath("%s.lock", git_HEAD);
1349         fd = open(lockpath, O_CREAT | O_EXCL | O_WRONLY, 0666);
1350         if (fd < 0) {
1351                 error("Unable to open %s for writing", lockpath);
1352                 goto error_free_return;
1353         }
1354         written = write_in_full(fd, ref, len);
1355         if (close(fd) != 0 || written != len) {
1356                 error("Unable to write to %s", lockpath);
1357                 goto error_unlink_return;
1358         }
1359         if (rename(lockpath, git_HEAD) < 0) {
1360                 error("Unable to create %s", git_HEAD);
1361                 goto error_unlink_return;
1362         }
1363         if (adjust_shared_perm(git_HEAD)) {
1364                 error("Unable to fix permissions on %s", lockpath);
1365         error_unlink_return:
1366                 unlink(lockpath);
1367         error_free_return:
1368                 free(git_HEAD);
1369                 return -1;
1370         }
1371
1372 #ifndef NO_SYMLINK_HEAD
1373         done:
1374 #endif
1375         if (logmsg && !read_ref(refs_heads_master, new_sha1))
1376                 log_ref_write(ref_target, old_sha1, new_sha1, logmsg);
1377
1378         free(git_HEAD);
1379         return 0;
1380 }
1381
1382 static char *ref_msg(const char *line, const char *endp)
1383 {
1384         const char *ep;
1385         line += 82;
1386         ep = memchr(line, '\n', endp - line);
1387         if (!ep)
1388                 ep = endp;
1389         return xmemdupz(line, ep - line);
1390 }
1391
1392 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)
1393 {
1394         const char *logfile, *logdata, *logend, *rec, *lastgt, *lastrec;
1395         char *tz_c;
1396         int logfd, tz, reccnt = 0;
1397         struct stat st;
1398         unsigned long date;
1399         unsigned char logged_sha1[20];
1400         void *log_mapped;
1401         size_t mapsz;
1402
1403         logfile = git_path("logs/%s", ref);
1404         logfd = open(logfile, O_RDONLY, 0);
1405         if (logfd < 0)
1406                 die("Unable to read log %s: %s", logfile, strerror(errno));
1407         fstat(logfd, &st);
1408         if (!st.st_size)
1409                 die("Log %s is empty.", logfile);
1410         mapsz = xsize_t(st.st_size);
1411         log_mapped = xmmap(NULL, mapsz, PROT_READ, MAP_PRIVATE, logfd, 0);
1412         logdata = log_mapped;
1413         close(logfd);
1414
1415         lastrec = NULL;
1416         rec = logend = logdata + st.st_size;
1417         while (logdata < rec) {
1418                 reccnt++;
1419                 if (logdata < rec && *(rec-1) == '\n')
1420                         rec--;
1421                 lastgt = NULL;
1422                 while (logdata < rec && *(rec-1) != '\n') {
1423                         rec--;
1424                         if (*rec == '>')
1425                                 lastgt = rec;
1426                 }
1427                 if (!lastgt)
1428                         die("Log %s is corrupt.", logfile);
1429                 date = strtoul(lastgt + 1, &tz_c, 10);
1430                 if (date <= at_time || cnt == 0) {
1431                         tz = strtoul(tz_c, NULL, 10);
1432                         if (msg)
1433                                 *msg = ref_msg(rec, logend);
1434                         if (cutoff_time)
1435                                 *cutoff_time = date;
1436                         if (cutoff_tz)
1437                                 *cutoff_tz = tz;
1438                         if (cutoff_cnt)
1439                                 *cutoff_cnt = reccnt - 1;
1440                         if (lastrec) {
1441                                 if (get_sha1_hex(lastrec, logged_sha1))
1442                                         die("Log %s is corrupt.", logfile);
1443                                 if (get_sha1_hex(rec + 41, sha1))
1444                                         die("Log %s is corrupt.", logfile);
1445                                 if (hashcmp(logged_sha1, sha1)) {
1446                                         fprintf(stderr,
1447                                                 "warning: Log %s has gap after %s.\n",
1448                                                 logfile, show_date(date, tz, DATE_RFC2822));
1449                                 }
1450                         }
1451                         else if (date == at_time) {
1452                                 if (get_sha1_hex(rec + 41, sha1))
1453                                         die("Log %s is corrupt.", logfile);
1454                         }
1455                         else {
1456                                 if (get_sha1_hex(rec + 41, logged_sha1))
1457                                         die("Log %s is corrupt.", logfile);
1458                                 if (hashcmp(logged_sha1, sha1)) {
1459                                         fprintf(stderr,
1460                                                 "warning: Log %s unexpectedly ended on %s.\n",
1461                                                 logfile, show_date(date, tz, DATE_RFC2822));
1462                                 }
1463                         }
1464                         munmap(log_mapped, mapsz);
1465                         return 0;
1466                 }
1467                 lastrec = rec;
1468                 if (cnt > 0)
1469                         cnt--;
1470         }
1471
1472         rec = logdata;
1473         while (rec < logend && *rec != '>' && *rec != '\n')
1474                 rec++;
1475         if (rec == logend || *rec == '\n')
1476                 die("Log %s is corrupt.", logfile);
1477         date = strtoul(rec + 1, &tz_c, 10);
1478         tz = strtoul(tz_c, NULL, 10);
1479         if (get_sha1_hex(logdata, sha1))
1480                 die("Log %s is corrupt.", logfile);
1481         if (is_null_sha1(sha1)) {
1482                 if (get_sha1_hex(logdata + 41, sha1))
1483                         die("Log %s is corrupt.", logfile);
1484         }
1485         if (msg)
1486                 *msg = ref_msg(logdata, logend);
1487         munmap(log_mapped, mapsz);
1488
1489         if (cutoff_time)
1490                 *cutoff_time = date;
1491         if (cutoff_tz)
1492                 *cutoff_tz = tz;
1493         if (cutoff_cnt)
1494                 *cutoff_cnt = reccnt;
1495         return 1;
1496 }
1497
1498 int for_each_recent_reflog_ent(const char *ref, each_reflog_ent_fn fn, long ofs, void *cb_data)
1499 {
1500         const char *logfile;
1501         FILE *logfp;
1502         char buf[1024];
1503         int ret = 0;
1504
1505         logfile = git_path("logs/%s", ref);
1506         logfp = fopen(logfile, "r");
1507         if (!logfp)
1508                 return -1;
1509
1510         if (ofs) {
1511                 struct stat statbuf;
1512                 if (fstat(fileno(logfp), &statbuf) ||
1513                     statbuf.st_size < ofs ||
1514                     fseek(logfp, -ofs, SEEK_END) ||
1515                     fgets(buf, sizeof(buf), logfp))
1516                         return -1;
1517         }
1518
1519         while (fgets(buf, sizeof(buf), logfp)) {
1520                 unsigned char osha1[20], nsha1[20];
1521                 char *email_end, *message;
1522                 unsigned long timestamp;
1523                 int len, tz;
1524
1525                 /* old SP new SP name <email> SP time TAB msg LF */
1526                 len = strlen(buf);
1527                 if (len < 83 || buf[len-1] != '\n' ||
1528                     get_sha1_hex(buf, osha1) || buf[40] != ' ' ||
1529                     get_sha1_hex(buf + 41, nsha1) || buf[81] != ' ' ||
1530                     !(email_end = strchr(buf + 82, '>')) ||
1531                     email_end[1] != ' ' ||
1532                     !(timestamp = strtoul(email_end + 2, &message, 10)) ||
1533                     !message || message[0] != ' ' ||
1534                     (message[1] != '+' && message[1] != '-') ||
1535                     !isdigit(message[2]) || !isdigit(message[3]) ||
1536                     !isdigit(message[4]) || !isdigit(message[5]))
1537                         continue; /* corrupt? */
1538                 email_end[1] = '\0';
1539                 tz = strtol(message + 1, NULL, 10);
1540                 if (message[6] != '\t')
1541                         message += 6;
1542                 else
1543                         message += 7;
1544                 ret = fn(osha1, nsha1, buf+82, timestamp, tz, message, cb_data);
1545                 if (ret)
1546                         break;
1547         }
1548         fclose(logfp);
1549         return ret;
1550 }
1551
1552 int for_each_reflog_ent(const char *ref, each_reflog_ent_fn fn, void *cb_data)
1553 {
1554         return for_each_recent_reflog_ent(ref, fn, 0, cb_data);
1555 }
1556
1557 static int do_for_each_reflog(const char *base, each_ref_fn fn, void *cb_data)
1558 {
1559         DIR *dir = opendir(git_path("logs/%s", base));
1560         int retval = 0;
1561
1562         if (dir) {
1563                 struct dirent *de;
1564                 int baselen = strlen(base);
1565                 char *log = xmalloc(baselen + 257);
1566
1567                 memcpy(log, base, baselen);
1568                 if (baselen && base[baselen-1] != '/')
1569                         log[baselen++] = '/';
1570
1571                 while ((de = readdir(dir)) != NULL) {
1572                         struct stat st;
1573                         int namelen;
1574
1575                         if (de->d_name[0] == '.')
1576                                 continue;
1577                         namelen = strlen(de->d_name);
1578                         if (namelen > 255)
1579                                 continue;
1580                         if (has_extension(de->d_name, ".lock"))
1581                                 continue;
1582                         memcpy(log + baselen, de->d_name, namelen+1);
1583                         if (stat(git_path("logs/%s", log), &st) < 0)
1584                                 continue;
1585                         if (S_ISDIR(st.st_mode)) {
1586                                 retval = do_for_each_reflog(log, fn, cb_data);
1587                         } else {
1588                                 unsigned char sha1[20];
1589                                 if (!resolve_ref(log, sha1, 0, NULL))
1590                                         retval = error("bad ref for %s", log);
1591                                 else
1592                                         retval = fn(log, sha1, 0, cb_data);
1593                         }
1594                         if (retval)
1595                                 break;
1596                 }
1597                 free(log);
1598                 closedir(dir);
1599         }
1600         else if (*base)
1601                 return errno;
1602         return retval;
1603 }
1604
1605 int for_each_reflog(each_ref_fn fn, void *cb_data)
1606 {
1607         return do_for_each_reflog("", fn, cb_data);
1608 }
1609
1610 int update_ref(const char *action, const char *refname,
1611                 const unsigned char *sha1, const unsigned char *oldval,
1612                 int flags, enum action_on_err onerr)
1613 {
1614         static struct ref_lock *lock;
1615         lock = lock_any_ref_for_update(refname, oldval, flags);
1616         if (!lock) {
1617                 const char *str = "Cannot lock the ref '%s'.";
1618                 switch (onerr) {
1619                 case MSG_ON_ERR: error(str, refname); break;
1620                 case DIE_ON_ERR: die(str, refname); break;
1621                 case QUIET_ON_ERR: break;
1622                 }
1623                 return 1;
1624         }
1625         if (write_ref_sha1(lock, sha1, action) < 0) {
1626                 const char *str = "Cannot update the ref '%s'.";
1627                 switch (onerr) {
1628                 case MSG_ON_ERR: error(str, refname); break;
1629                 case DIE_ON_ERR: die(str, refname); break;
1630                 case QUIET_ON_ERR: break;
1631                 }
1632                 return 1;
1633         }
1634         return 0;
1635 }
1636
1637 struct ref *find_ref_by_name(const struct ref *list, const char *name)
1638 {
1639         for ( ; list; list = list->next)
1640                 if (!strcmp(list->name, name))
1641                         return (struct ref *)list;
1642         return NULL;
1643 }