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