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                 char path[PATH_MAX];
 417                 struct stat st;
 418                 char *buf;
 419                 int fd;
 420
 421                 if (--depth < 0)
 422                         return NULL;
 423
 424                 git_snpath(path, sizeof(path), "%s", ref);
 425                 /* Special case: non-existing file. */
 426                 if (lstat(path, &st) < 0) {
 427                         struct ref_list *list = get_packed_refs();
 428                         while (list) {
 429                                 if (!strcmp(ref, list->name)) {
 430                                         hashcpy(sha1, list->sha1);
 431                                         if (flag)
 432                                                 *flag |= REF_ISPACKED;
 433                                         return ref;
 434                                 }
 435                                 list = list->next;
 436                         }
 437                         if (reading || errno != ENOENT)
 438                                 return NULL;
 439                         hashclr(sha1);
 440                         return ref;
 441                 }
 442
 443                 /* Follow "normalized" - ie "refs/.." symlinks by hand */
 444                 if (S_ISLNK(st.st_mode)) {
 445                         len = readlink(path, buffer, sizeof(buffer)-1);
 446                         if (len >= 5 && !memcmp("refs/", buffer, 5)) {
 447                                 buffer[len] = 0;
 448                                 strcpy(ref_buffer, buffer);
 449                                 ref = ref_buffer;
 450                                 if (flag)
 451                                         *flag |= REF_ISSYMREF;
 452                                 continue;
 453                         }
 454                 }
 455
 456                 /* Is it a directory? */
 457                 if (S_ISDIR(st.st_mode)) {
 458                         errno = EISDIR;
 459                         return NULL;
 460                 }
 461
 462                 /*
 463                  * Anything else, just open it and try to use it as
 464                  * a ref
 465                  */
 466                 fd = open(path, O_RDONLY);
 467                 if (fd < 0)
 468                         return NULL;
 469                 len = read_in_full(fd, buffer, sizeof(buffer)-1);
 470                 close(fd);
 471
 472                 /*
 473                  * Is it a symbolic ref?
 474                  */
 475                 if (len < 4 || memcmp("ref:", buffer, 4))
 476                         break;
 477                 buf = buffer + 4;
 478                 len -= 4;
 479                 while (len && isspace(*buf))
 480                         buf++, len--;
 481                 while (len && isspace(buf[len-1]))
 482                         len--;
 483                 buf[len] = 0;
 484                 memcpy(ref_buffer, buf, len + 1);
 485                 ref = ref_buffer;
 486                 if (flag)
 487                         *flag |= REF_ISSYMREF;
 488         }
 489         if (len < 40 || get_sha1_hex(buffer, sha1))
 490                 return NULL;
 491         return ref;
 492 }
 493
 494 int read_ref(const char *ref, unsigned char *sha1)
 495 {
 496         if (resolve_ref(ref, sha1, 1, NULL))
 497                 return 0;
 498         return -1;
 499 }
 500
 501 static int do_one_ref(const char *base, each_ref_fn fn, int trim,
 502                       void *cb_data, struct ref_list *entry)
 503 {
 504         if (strncmp(base, entry->name, trim))
 505                 return 0;
 506         if (is_null_sha1(entry->sha1))
 507                 return 0;
 508         if (!has_sha1_file(entry->sha1)) {
 509                 error("%s does not point to a valid object!", entry->name);
 510                 return 0;
 511         }
 512         current_ref = entry;
 513         return fn(entry->name + trim, entry->sha1, entry->flag, cb_data);
 514 }
 515
 516 int peel_ref(const char *ref, unsigned char *sha1)
 517 {
 518         int flag;
 519         unsigned char base[20];
 520         struct object *o;
 521
 522         if (current_ref && (current_ref->name == ref
 523                 || !strcmp(current_ref->name, ref))) {
 524                 if (current_ref->flag & REF_KNOWS_PEELED) {
 525                         hashcpy(sha1, current_ref->peeled);
 526                         return 0;
 527                 }
 528                 hashcpy(base, current_ref->sha1);
 529                 goto fallback;
 530         }
 531
 532         if (!resolve_ref(ref, base, 1, &flag))
 533                 return -1;
 534
 535         if ((flag & REF_ISPACKED)) {
 536                 struct ref_list *list = get_packed_refs();
 537
 538                 while (list) {
 539                         if (!strcmp(list->name, ref)) {
 540                                 if (list->flag & REF_KNOWS_PEELED) {
 541                                         hashcpy(sha1, list->peeled);
 542                                         return 0;
 543                                 }
 544                                 /* older pack-refs did not leave peeled ones */
 545                                 break;
 546                         }
 547                         list = list->next;
 548                 }
 549         }
 550
 551 fallback:
 552         o = parse_object(base);
 553         if (o && o->type == OBJ_TAG) {
 554                 o = deref_tag(o, ref, 0);
 555                 if (o) {
 556                         hashcpy(sha1, o->sha1);
 557                         return 0;
 558                 }
 559         }
 560         return -1;
 561 }
 562
 563 static int do_for_each_ref(const char *base, each_ref_fn fn, int trim,
 564                            void *cb_data)
 565 {
 566         int retval = 0;
 567         struct ref_list *packed = get_packed_refs();
 568         struct ref_list *loose = get_loose_refs();
 569
 570         struct ref_list *extra;
 571
 572         for (extra = extra_refs; extra; extra = extra->next)
 573                 retval = do_one_ref(base, fn, trim, cb_data, extra);
 574
 575         while (packed && loose) {
 576                 struct ref_list *entry;
 577                 int cmp = strcmp(packed->name, loose->name);
 578                 if (!cmp) {
 579                         packed = packed->next;
 580                         continue;
 581                 }
 582                 if (cmp > 0) {
 583                         entry = loose;
 584                         loose = loose->next;
 585                 } else {
 586                         entry = packed;
 587                         packed = packed->next;
 588                 }
 589                 retval = do_one_ref(base, fn, trim, cb_data, entry);
 590                 if (retval)
 591                         goto end_each;
 592         }
 593
 594         for (packed = packed ? packed : loose; packed; packed = packed->next) {
 595                 retval = do_one_ref(base, fn, trim, cb_data, packed);
 596                 if (retval)
 597                         goto end_each;
 598         }
 599
 600 end_each:
 601         current_ref = NULL;
 602         return retval;
 603 }
 604
 605 int head_ref(each_ref_fn fn, void *cb_data)
 606 {
 607         unsigned char sha1[20];
 608         int flag;
 609
 610         if (resolve_ref("HEAD", sha1, 1, &flag))
 611                 return fn("HEAD", sha1, flag, cb_data);
 612         return 0;
 613 }
 614
 615 int for_each_ref(each_ref_fn fn, void *cb_data)
 616 {
 617         return do_for_each_ref("refs/", fn, 0, cb_data);
 618 }
 619
 620 int for_each_tag_ref(each_ref_fn fn, void *cb_data)
 621 {
 622         return do_for_each_ref("refs/tags/", fn, 10, cb_data);
 623 }
 624
 625 int for_each_branch_ref(each_ref_fn fn, void *cb_data)
 626 {
 627         return do_for_each_ref("refs/heads/", fn, 11, cb_data);
 628 }
 629
 630 int for_each_remote_ref(each_ref_fn fn, void *cb_data)
 631 {
 632         return do_for_each_ref("refs/remotes/", fn, 13, cb_data);
 633 }
 634
 635 /*
 636  * Make sure "ref" is something reasonable to have under ".git/refs/";
 637  * We do not like it if:
 638  *
 639  * - any path component of it begins with ".", or
 640  * - it has double dots "..", or
 641  * - it has ASCII control character, "~", "^", ":" or SP, anywhere, or
 642  * - it ends with a "/".
 643  */
 644
 645 static inline int bad_ref_char(int ch)
 646 {
 647         if (((unsigned) ch) <= ' ' ||
 648             ch == '~' || ch == '^' || ch == ':')
 649                 return 1;
 650         /* 2.13 Pattern Matching Notation */
 651         if (ch == '?' || ch == '[') /* Unsupported */
 652                 return 1;
 653         if (ch == '*') /* Supported at the end */
 654                 return 2;
 655         return 0;
 656 }
 657
 658 int check_ref_format(const char *ref)
 659 {
 660         int ch, level, bad_type;
 661         const char *cp = ref;
 662
 663         level = 0;
 664         while (1) {
 665                 while ((ch = *cp++) == '/')
 666                         ; /* tolerate duplicated slashes */
 667                 if (!ch)
 668                         /* should not end with slashes */
 669                         return CHECK_REF_FORMAT_ERROR;
 670
 671                 /* we are at the beginning of the path component */
 672                 if (ch == '.')
 673                         return CHECK_REF_FORMAT_ERROR;
 674                 bad_type = bad_ref_char(ch);
 675                 if (bad_type) {
 676                         return (bad_type == 2 && !*cp)
 677                                 ? CHECK_REF_FORMAT_WILDCARD
 678                                 : CHECK_REF_FORMAT_ERROR;
 679                 }
 680
 681                 /* scan the rest of the path component */
 682                 while ((ch = *cp++) != 0) {
 683                         bad_type = bad_ref_char(ch);
 684                         if (bad_type) {
 685                                 return (bad_type == 2 && !*cp)
 686                                         ? CHECK_REF_FORMAT_WILDCARD
 687                                         : CHECK_REF_FORMAT_ERROR;
 688                         }
 689                         if (ch == '/')
 690                                 break;
 691                         if (ch == '.' && *cp == '.')
 692                                 return CHECK_REF_FORMAT_ERROR;
 693                 }
 694                 level++;
 695                 if (!ch) {
 696                         if (level < 2)
 697                                 return CHECK_REF_FORMAT_ONELEVEL;
 698                         return CHECK_REF_FORMAT_OK;
 699                 }
 700         }
 701 }
 702
 703 const char *ref_rev_parse_rules[] = {
 704         "%.*s",
 705         "refs/%.*s",
 706         "refs/tags/%.*s",
 707         "refs/heads/%.*s",
 708         "refs/remotes/%.*s",
 709         "refs/remotes/%.*s/HEAD",
 710         NULL
 711 };
 712
 713 const char *ref_fetch_rules[] = {
 714         "%.*s",
 715         "refs/%.*s",
 716         "refs/heads/%.*s",
 717         NULL
 718 };
 719
 720 int refname_match(const char *abbrev_name, const char *full_name, const char **rules)
 721 {
 722         const char **p;
 723         const int abbrev_name_len = strlen(abbrev_name);
 724
 725         for (p = rules; *p; p++) {
 726                 if (!strcmp(full_name, mkpath(*p, abbrev_name_len, abbrev_name))) {
 727                         return 1;
 728                 }
 729         }
 730
 731         return 0;
 732 }
 733
 734 static struct ref_lock *verify_lock(struct ref_lock *lock,
 735         const unsigned char *old_sha1, int mustexist)
 736 {
 737         if (!resolve_ref(lock->ref_name, lock->old_sha1, mustexist, NULL)) {
 738                 error("Can't verify ref %s", lock->ref_name);
 739                 unlock_ref(lock);
 740                 return NULL;
 741         }
 742         if (hashcmp(lock->old_sha1, old_sha1)) {
 743                 error("Ref %s is at %s but expected %s", lock->ref_name,
 744                         sha1_to_hex(lock->old_sha1), sha1_to_hex(old_sha1));
 745                 unlock_ref(lock);
 746                 return NULL;
 747         }
 748         return lock;
 749 }
 750
 751 static int remove_empty_directories(const char *file)
 752 {
 753         /* we want to create a file but there is a directory there;
 754          * if that is an empty directory (or a directory that contains
 755          * only empty directories), remove them.
 756          */
 757         struct strbuf path;
 758         int result;
 759
 760         strbuf_init(&path, 20);
 761         strbuf_addstr(&path, file);
 762
 763         result = remove_dir_recursively(&path, 1);
 764
 765         strbuf_release(&path);
 766
 767         return result;
 768 }
 769
 770 static int is_refname_available(const char *ref, const char *oldref,
 771                                 struct ref_list *list, int quiet)
 772 {
 773         int namlen = strlen(ref); /* e.g. 'foo/bar' */
 774         while (list) {
 775                 /* list->name could be 'foo' or 'foo/bar/baz' */
 776                 if (!oldref || strcmp(oldref, list->name)) {
 777                         int len = strlen(list->name);
 778                         int cmplen = (namlen < len) ? namlen : len;
 779                         const char *lead = (namlen < len) ? list->name : ref;
 780                         if (!strncmp(ref, list->name, cmplen) &&
 781                             lead[cmplen] == '/') {
 782                                 if (!quiet)
 783                                         error("'%s' exists; cannot create '%s'",
 784                                               list->name, ref);
 785                                 return 0;
 786                         }
 787                 }
 788                 list = list->next;
 789         }
 790         return 1;
 791 }
 792
 793 static struct ref_lock *lock_ref_sha1_basic(const char *ref, const unsigned char *old_sha1, int flags, int *type_p)
 794 {
 795         char *ref_file;
 796         const char *orig_ref = ref;
 797         struct ref_lock *lock;
 798         int last_errno = 0;
 799         int type, lflags;
 800         int mustexist = (old_sha1 && !is_null_sha1(old_sha1));
 801         int missing = 0;
 802
 803         lock = xcalloc(1, sizeof(struct ref_lock));
 804         lock->lock_fd = -1;
 805
 806         ref = resolve_ref(ref, lock->old_sha1, mustexist, &type);
 807         if (!ref && errno == EISDIR) {
 808                 /* we are trying to lock foo but we used to
 809                  * have foo/bar which now does not exist;
 810                  * it is normal for the empty directory 'foo'
 811                  * to remain.
 812                  */
 813                 ref_file = git_path("%s", orig_ref);
 814                 if (remove_empty_directories(ref_file)) {
 815                         last_errno = errno;
 816                         error("there are still refs under '%s'", orig_ref);
 817                         goto error_return;
 818                 }
 819                 ref = resolve_ref(orig_ref, lock->old_sha1, mustexist, &type);
 820         }
 821         if (type_p)
 822             *type_p = type;
 823         if (!ref) {
 824                 last_errno = errno;
 825                 error("unable to resolve reference %s: %s",
 826                         orig_ref, strerror(errno));
 827                 goto error_return;
 828         }
 829         missing = is_null_sha1(lock->old_sha1);
 830         /* When the ref did not exist and we are creating it,
 831          * make sure there is no existing ref that is packed
 832          * whose name begins with our refname, nor a ref whose
 833          * name is a proper prefix of our refname.
 834          */
 835         if (missing &&
 836             !is_refname_available(ref, NULL, get_packed_refs(), 0))
 837                 goto error_return;
 838
 839         lock->lk = xcalloc(1, sizeof(struct lock_file));
 840
 841         lflags = LOCK_DIE_ON_ERROR;
 842         if (flags & REF_NODEREF) {
 843                 ref = orig_ref;
 844                 lflags |= LOCK_NODEREF;
 845         }
 846         lock->ref_name = xstrdup(ref);
 847         lock->orig_ref_name = xstrdup(orig_ref);
 848         ref_file = git_path("%s", ref);
 849         if (missing)
 850                 lock->force_write = 1;
 851         if ((flags & REF_NODEREF) && (type & REF_ISSYMREF))
 852                 lock->force_write = 1;
 853
 854         if (safe_create_leading_directories(ref_file)) {
 855                 last_errno = errno;
 856                 error("unable to create directory for %s", ref_file);
 857                 goto error_return;
 858         }
 859
 860         lock->lock_fd = hold_lock_file_for_update(lock->lk, ref_file, lflags);
 861         return old_sha1 ? verify_lock(lock, old_sha1, mustexist) : lock;
 862
 863  error_return:
 864         unlock_ref(lock);
 865         errno = last_errno;
 866         return NULL;
 867 }
 868
 869 struct ref_lock *lock_ref_sha1(const char *ref, const unsigned char *old_sha1)
 870 {
 871         char refpath[PATH_MAX];
 872         if (check_ref_format(ref))
 873                 return NULL;
 874         strcpy(refpath, mkpath("refs/%s", ref));
 875         return lock_ref_sha1_basic(refpath, old_sha1, 0, NULL);
 876 }
 877
 878 struct ref_lock *lock_any_ref_for_update(const char *ref, const unsigned char *old_sha1, int flags)
 879 {
 880         switch (check_ref_format(ref)) {
 881         default:
 882                 return NULL;
 883         case 0:
 884         case CHECK_REF_FORMAT_ONELEVEL:
 885                 return lock_ref_sha1_basic(ref, old_sha1, flags, NULL);
 886         }
 887 }
 888
 889 static struct lock_file packlock;
 890
 891 static int repack_without_ref(const char *refname)
 892 {
 893         struct ref_list *list, *packed_ref_list;
 894         int fd;
 895         int found = 0;
 896
 897         packed_ref_list = get_packed_refs();
 898         for (list = packed_ref_list; list; list = list->next) {
 899                 if (!strcmp(refname, list->name)) {
 900                         found = 1;
 901                         break;
 902                 }
 903         }
 904         if (!found)
 905                 return 0;
 906         fd = hold_lock_file_for_update(&packlock, git_path("packed-refs"), 0);
 907         if (fd < 0)
 908                 return error("cannot delete '%s' from packed refs", refname);
 909
 910         for (list = packed_ref_list; list; list = list->next) {
 911                 char line[PATH_MAX + 100];
 912                 int len;
 913
 914                 if (!strcmp(refname, list->name))
 915                         continue;
 916                 len = snprintf(line, sizeof(line), "%s %s\n",
 917                                sha1_to_hex(list->sha1), list->name);
 918                 /* this should not happen but just being defensive */
 919                 if (len > sizeof(line))
 920                         die("too long a refname '%s'", list->name);
 921                 write_or_die(fd, line, len);
 922         }
 923         return commit_lock_file(&packlock);
 924 }
 925
 926 int delete_ref(const char *refname, const unsigned char *sha1, int delopt)
 927 {
 928         struct ref_lock *lock;
 929         int err, i = 0, ret = 0, flag = 0;
 930
 931         lock = lock_ref_sha1_basic(refname, sha1, 0, &flag);
 932         if (!lock)
 933                 return 1;
 934         if (!(flag & REF_ISPACKED) || flag & REF_ISSYMREF) {
 935                 /* loose */
 936                 const char *path;
 937
 938                 if (!(delopt & REF_NODEREF)) {
 939                         i = strlen(lock->lk->filename) - 5; /* .lock */
 940                         lock->lk->filename[i] = 0;
 941                         path = lock->lk->filename;
 942                 } else {
 943                         path = git_path("%s", refname);
 944                 }
 945                 err = unlink(path);
 946                 if (err && errno != ENOENT) {
 947                         ret = 1;
 948                         error("unlink(%s) failed: %s",
 949                               path, strerror(errno));
 950                 }
 951                 if (!(delopt & REF_NODEREF))
 952                         lock->lk->filename[i] = '.';
 953         }
 954         /* removing the loose one could have resurrected an earlier
 955          * packed one.  Also, if it was not loose we need to repack
 956          * without it.
 957          */
 958         ret |= repack_without_ref(refname);
 959
 960         err = unlink(git_path("logs/%s", lock->ref_name));
 961         if (err && errno != ENOENT)
 962                 fprintf(stderr, "warning: unlink(%s) failed: %s",
 963                         git_path("logs/%s", lock->ref_name), strerror(errno));
 964         invalidate_cached_refs();
 965         unlock_ref(lock);
 966         return ret;
 967 }
 968
 969 int rename_ref(const char *oldref, const char *newref, const char *logmsg)
 970 {
 971         static const char renamed_ref[] = "RENAMED-REF";
 972         unsigned char sha1[20], orig_sha1[20];
 973         int flag = 0, logmoved = 0;
 974         struct ref_lock *lock;
 975         struct stat loginfo;
 976         int log = !lstat(git_path("logs/%s", oldref), &loginfo);
 977         const char *symref = NULL;
 978
 979         if (log && S_ISLNK(loginfo.st_mode))
 980                 return error("reflog for %s is a symlink", oldref);
 981
 982         symref = resolve_ref(oldref, orig_sha1, 1, &flag);
 983         if (flag & REF_ISSYMREF)
 984                 return error("refname %s is a symbolic ref, renaming it is not supported",
 985                         oldref);
 986         if (!symref)
 987                 return error("refname %s not found", oldref);
 988
 989         if (!is_refname_available(newref, oldref, get_packed_refs(), 0))
 990                 return 1;
 991
 992         if (!is_refname_available(newref, oldref, get_loose_refs(), 0))
 993                 return 1;
 994
 995         lock = lock_ref_sha1_basic(renamed_ref, NULL, 0, NULL);
 996         if (!lock)
 997                 return error("unable to lock %s", renamed_ref);
 998         lock->force_write = 1;
 999         if (write_ref_sha1(lock, orig_sha1, logmsg))
1000                 return error("unable to save current sha1 in %s", renamed_ref);
1001
1002         if (log && rename(git_path("logs/%s", oldref), git_path("tmp-renamed-log")))
1003                 return error("unable to move logfile logs/%s to tmp-renamed-log: %s",
1004                         oldref, strerror(errno));
1005
1006         if (delete_ref(oldref, orig_sha1, REF_NODEREF)) {
1007                 error("unable to delete old %s", oldref);
1008                 goto rollback;
1009         }
1010
1011         if (resolve_ref(newref, sha1, 1, &flag) && delete_ref(newref, sha1, REF_NODEREF)) {
1012                 if (errno==EISDIR) {
1013                         if (remove_empty_directories(git_path("%s", newref))) {
1014                                 error("Directory not empty: %s", newref);
1015                                 goto rollback;
1016                         }
1017                 } else {
1018                         error("unable to delete existing %s", newref);
1019                         goto rollback;
1020                 }
1021         }
1022
1023         if (log && safe_create_leading_directories(git_path("logs/%s", newref))) {
1024                 error("unable to create directory for %s", newref);
1025                 goto rollback;
1026         }
1027
1028  retry:
1029         if (log && rename(git_path("tmp-renamed-log"), git_path("logs/%s", newref))) {
1030                 if (errno==EISDIR || errno==ENOTDIR) {
1031                         /*
1032                          * rename(a, b) when b is an existing
1033                          * directory ought to result in ISDIR, but
1034                          * Solaris 5.8 gives ENOTDIR.  Sheesh.
1035                          */
1036                         if (remove_empty_directories(git_path("logs/%s", newref))) {
1037                                 error("Directory not empty: logs/%s", newref);
1038                                 goto rollback;
1039                         }
1040                         goto retry;
1041                 } else {
1042                         error("unable to move logfile tmp-renamed-log to logs/%s: %s",
1043                                 newref, strerror(errno));
1044                         goto rollback;
1045                 }
1046         }
1047         logmoved = log;
1048
1049         lock = lock_ref_sha1_basic(newref, NULL, 0, NULL);
1050         if (!lock) {
1051                 error("unable to lock %s for update", newref);
1052                 goto rollback;
1053         }
1054         lock->force_write = 1;
1055         hashcpy(lock->old_sha1, orig_sha1);
1056         if (write_ref_sha1(lock, orig_sha1, logmsg)) {
1057                 error("unable to write current sha1 into %s", newref);
1058                 goto rollback;
1059         }
1060
1061         return 0;
1062
1063  rollback:
1064         lock = lock_ref_sha1_basic(oldref, NULL, 0, NULL);
1065         if (!lock) {
1066                 error("unable to lock %s for rollback", oldref);
1067                 goto rollbacklog;
1068         }
1069
1070         lock->force_write = 1;
1071         flag = log_all_ref_updates;
1072         log_all_ref_updates = 0;
1073         if (write_ref_sha1(lock, orig_sha1, NULL))
1074                 error("unable to write current sha1 into %s", oldref);
1075         log_all_ref_updates = flag;
1076
1077  rollbacklog:
1078         if (logmoved && rename(git_path("logs/%s", newref), git_path("logs/%s", oldref)))
1079                 error("unable to restore logfile %s from %s: %s",
1080                         oldref, newref, strerror(errno));
1081         if (!logmoved && log &&
1082             rename(git_path("tmp-renamed-log"), git_path("logs/%s", oldref)))
1083                 error("unable to restore logfile %s from tmp-renamed-log: %s",
1084                         oldref, strerror(errno));
1085
1086         return 1;
1087 }
1088
1089 int close_ref(struct ref_lock *lock)
1090 {
1091         if (close_lock_file(lock->lk))
1092                 return -1;
1093         lock->lock_fd = -1;
1094         return 0;
1095 }
1096
1097 int commit_ref(struct ref_lock *lock)
1098 {
1099         if (commit_lock_file(lock->lk))
1100                 return -1;
1101         lock->lock_fd = -1;
1102         return 0;
1103 }
1104
1105 void unlock_ref(struct ref_lock *lock)
1106 {
1107         /* Do not free lock->lk -- atexit() still looks at them */
1108         if (lock->lk)
1109                 rollback_lock_file(lock->lk);
1110         free(lock->ref_name);
1111         free(lock->orig_ref_name);
1112         free(lock);
1113 }
1114
1115 /*
1116  * copy the reflog message msg to buf, which has been allocated sufficiently
1117  * large, while cleaning up the whitespaces.  Especially, convert LF to space,
1118  * because reflog file is one line per entry.
1119  */
1120 static int copy_msg(char *buf, const char *msg)
1121 {
1122         char *cp = buf;
1123         char c;
1124         int wasspace = 1;
1125
1126         *cp++ = '\t';
1127         while ((c = *msg++)) {
1128                 if (wasspace && isspace(c))
1129                         continue;
1130                 wasspace = isspace(c);
1131                 if (wasspace)
1132                         c = ' ';
1133                 *cp++ = c;
1134         }
1135         while (buf < cp && isspace(cp[-1]))
1136                 cp--;
1137         *cp++ = '\n';
1138         return cp - buf;
1139 }
1140
1141 static int log_ref_write(const char *ref_name, const unsigned char *old_sha1,
1142                          const unsigned char *new_sha1, const char *msg)
1143 {
1144         int logfd, written, oflags = O_APPEND | O_WRONLY;
1145         unsigned maxlen, len;
1146         int msglen;
1147         char log_file[PATH_MAX];
1148         char *logrec;
1149         const char *committer;
1150
1151         if (log_all_ref_updates < 0)
1152                 log_all_ref_updates = !is_bare_repository();
1153
1154         git_snpath(log_file, sizeof(log_file), "logs/%s", ref_name);
1155
1156         if (log_all_ref_updates &&
1157             (!prefixcmp(ref_name, "refs/heads/") ||
1158              !prefixcmp(ref_name, "refs/remotes/") ||
1159              !strcmp(ref_name, "HEAD"))) {
1160                 if (safe_create_leading_directories(log_file) < 0)
1161                         return error("unable to create directory for %s",
1162                                      log_file);
1163                 oflags |= O_CREAT;
1164         }
1165
1166         logfd = open(log_file, oflags, 0666);
1167         if (logfd < 0) {
1168                 if (!(oflags & O_CREAT) && errno == ENOENT)
1169                         return 0;
1170
1171                 if ((oflags & O_CREAT) && errno == EISDIR) {
1172                         if (remove_empty_directories(log_file)) {
1173                                 return error("There are still logs under '%s'",
1174                                              log_file);
1175                         }
1176                         logfd = open(log_file, oflags, 0666);
1177                 }
1178
1179                 if (logfd < 0)
1180                         return error("Unable to append to %s: %s",
1181                                      log_file, strerror(errno));
1182         }
1183
1184         adjust_shared_perm(log_file);
1185
1186         msglen = msg ? strlen(msg) : 0;
1187         committer = git_committer_info(0);
1188         maxlen = strlen(committer) + msglen + 100;
1189         logrec = xmalloc(maxlen);
1190         len = sprintf(logrec, "%s %s %s\n",
1191                       sha1_to_hex(old_sha1),
1192                       sha1_to_hex(new_sha1),
1193                       committer);
1194         if (msglen)
1195                 len += copy_msg(logrec + len - 1, msg) - 1;
1196         written = len <= maxlen ? write_in_full(logfd, logrec, len) : -1;
1197         free(logrec);
1198         if (close(logfd) != 0 || written != len)
1199                 return error("Unable to append to %s", log_file);
1200         return 0;
1201 }
1202
1203 static int is_branch(const char *refname)
1204 {
1205         return !strcmp(refname, "HEAD") || !prefixcmp(refname, "refs/heads/");
1206 }
1207
1208 int write_ref_sha1(struct ref_lock *lock,
1209         const unsigned char *sha1, const char *logmsg)
1210 {
1211         static char term = '\n';
1212         struct object *o;
1213
1214         if (!lock)
1215                 return -1;
1216         if (!lock->force_write && !hashcmp(lock->old_sha1, sha1)) {
1217                 unlock_ref(lock);
1218                 return 0;
1219         }
1220         o = parse_object(sha1);
1221         if (!o) {
1222                 error("Trying to write ref %s with nonexistant object %s",
1223                         lock->ref_name, sha1_to_hex(sha1));
1224                 unlock_ref(lock);
1225                 return -1;
1226         }
1227         if (o->type != OBJ_COMMIT && is_branch(lock->ref_name)) {
1228                 error("Trying to write non-commit object %s to branch %s",
1229                         sha1_to_hex(sha1), lock->ref_name);
1230                 unlock_ref(lock);
1231                 return -1;
1232         }
1233         if (write_in_full(lock->lock_fd, sha1_to_hex(sha1), 40) != 40 ||
1234             write_in_full(lock->lock_fd, &term, 1) != 1
1235                 || close_ref(lock) < 0) {
1236                 error("Couldn't write %s", lock->lk->filename);
1237                 unlock_ref(lock);
1238                 return -1;
1239         }
1240         invalidate_cached_refs();
1241         if (log_ref_write(lock->ref_name, lock->old_sha1, sha1, logmsg) < 0 ||
1242             (strcmp(lock->ref_name, lock->orig_ref_name) &&
1243              log_ref_write(lock->orig_ref_name, lock->old_sha1, sha1, logmsg) < 0)) {
1244                 unlock_ref(lock);
1245                 return -1;
1246         }
1247         if (strcmp(lock->orig_ref_name, "HEAD") != 0) {
1248                 /*
1249                  * Special hack: If a branch is updated directly and HEAD
1250                  * points to it (may happen on the remote side of a push
1251                  * for example) then logically the HEAD reflog should be
1252                  * updated too.
1253                  * A generic solution implies reverse symref information,
1254                  * but finding all symrefs pointing to the given branch
1255                  * would be rather costly for this rare event (the direct
1256                  * update of a branch) to be worth it.  So let's cheat and
1257                  * check with HEAD only which should cover 99% of all usage
1258                  * scenarios (even 100% of the default ones).
1259                  */
1260                 unsigned char head_sha1[20];
1261                 int head_flag;
1262                 const char *head_ref;
1263                 head_ref = resolve_ref("HEAD", head_sha1, 1, &head_flag);
1264                 if (head_ref && (head_flag & REF_ISSYMREF) &&
1265                     !strcmp(head_ref, lock->ref_name))
1266                         log_ref_write("HEAD", lock->old_sha1, sha1, logmsg);
1267         }
1268         if (commit_ref(lock)) {
1269                 error("Couldn't set %s", lock->ref_name);
1270                 unlock_ref(lock);
1271                 return -1;
1272         }
1273         unlock_ref(lock);
1274         return 0;
1275 }
1276
1277 int create_symref(const char *ref_target, const char *refs_heads_master,
1278                   const char *logmsg)
1279 {
1280         const char *lockpath;
1281         char ref[1000];
1282         int fd, len, written;
1283         char *git_HEAD = git_pathdup("%s", ref_target);
1284         unsigned char old_sha1[20], new_sha1[20];
1285
1286         if (logmsg && read_ref(ref_target, old_sha1))
1287                 hashclr(old_sha1);
1288
1289         if (safe_create_leading_directories(git_HEAD) < 0)
1290                 return error("unable to create directory for %s", git_HEAD);
1291
1292 #ifndef NO_SYMLINK_HEAD
1293         if (prefer_symlink_refs) {
1294                 unlink(git_HEAD);
1295                 if (!symlink(refs_heads_master, git_HEAD))
1296                         goto done;
1297                 fprintf(stderr, "no symlink - falling back to symbolic ref\n");
1298         }
1299 #endif
1300
1301         len = snprintf(ref, sizeof(ref), "ref: %s\n", refs_heads_master);
1302         if (sizeof(ref) <= len) {
1303                 error("refname too long: %s", refs_heads_master);
1304                 goto error_free_return;
1305         }
1306         lockpath = mkpath("%s.lock", git_HEAD);
1307         fd = open(lockpath, O_CREAT | O_EXCL | O_WRONLY, 0666);
1308         if (fd < 0) {
1309                 error("Unable to open %s for writing", lockpath);
1310                 goto error_free_return;
1311         }
1312         written = write_in_full(fd, ref, len);
1313         if (close(fd) != 0 || written != len) {
1314                 error("Unable to write to %s", lockpath);
1315                 goto error_unlink_return;
1316         }
1317         if (rename(lockpath, git_HEAD) < 0) {
1318                 error("Unable to create %s", git_HEAD);
1319                 goto error_unlink_return;
1320         }
1321         if (adjust_shared_perm(git_HEAD)) {
1322                 error("Unable to fix permissions on %s", lockpath);
1323         error_unlink_return:
1324                 unlink(lockpath);
1325         error_free_return:
1326                 free(git_HEAD);
1327                 return -1;
1328         }
1329
1330 #ifndef NO_SYMLINK_HEAD
1331         done:
1332 #endif
1333         if (logmsg && !read_ref(refs_heads_master, new_sha1))
1334                 log_ref_write(ref_target, old_sha1, new_sha1, logmsg);
1335
1336         free(git_HEAD);
1337         return 0;
1338 }
1339
1340 static char *ref_msg(const char *line, const char *endp)
1341 {
1342         const char *ep;
1343         line += 82;
1344         ep = memchr(line, '\n', endp - line);
1345         if (!ep)
1346                 ep = endp;
1347         return xmemdupz(line, ep - line);
1348 }
1349
1350 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)
1351 {
1352         const char *logfile, *logdata, *logend, *rec, *lastgt, *lastrec;
1353         char *tz_c;
1354         int logfd, tz, reccnt = 0;
1355         struct stat st;
1356         unsigned long date;
1357         unsigned char logged_sha1[20];
1358         void *log_mapped;
1359         size_t mapsz;
1360
1361         logfile = git_path("logs/%s", ref);
1362         logfd = open(logfile, O_RDONLY, 0);
1363         if (logfd < 0)
1364                 die("Unable to read log %s: %s", logfile, strerror(errno));
1365         fstat(logfd, &st);
1366         if (!st.st_size)
1367                 die("Log %s is empty.", logfile);
1368         mapsz = xsize_t(st.st_size);
1369         log_mapped = xmmap(NULL, mapsz, PROT_READ, MAP_PRIVATE, logfd, 0);
1370         logdata = log_mapped;
1371         close(logfd);
1372
1373         lastrec = NULL;
1374         rec = logend = logdata + st.st_size;
1375         while (logdata < rec) {
1376                 reccnt++;
1377                 if (logdata < rec && *(rec-1) == '\n')
1378                         rec--;
1379                 lastgt = NULL;
1380                 while (logdata < rec && *(rec-1) != '\n') {
1381                         rec--;
1382                         if (*rec == '>')
1383                                 lastgt = rec;
1384                 }
1385                 if (!lastgt)
1386                         die("Log %s is corrupt.", logfile);
1387                 date = strtoul(lastgt + 1, &tz_c, 10);
1388                 if (date <= at_time || cnt == 0) {
1389                         tz = strtoul(tz_c, NULL, 10);
1390                         if (msg)
1391                                 *msg = ref_msg(rec, logend);
1392                         if (cutoff_time)
1393                                 *cutoff_time = date;
1394                         if (cutoff_tz)
1395                                 *cutoff_tz = tz;
1396                         if (cutoff_cnt)
1397                                 *cutoff_cnt = reccnt - 1;
1398                         if (lastrec) {
1399                                 if (get_sha1_hex(lastrec, logged_sha1))
1400                                         die("Log %s is corrupt.", logfile);
1401                                 if (get_sha1_hex(rec + 41, sha1))
1402                                         die("Log %s is corrupt.", logfile);
1403                                 if (hashcmp(logged_sha1, sha1)) {
1404                                         fprintf(stderr,
1405                                                 "warning: Log %s has gap after %s.\n",
1406                                                 logfile, show_date(date, tz, DATE_RFC2822));
1407                                 }
1408                         }
1409                         else if (date == at_time) {
1410                                 if (get_sha1_hex(rec + 41, sha1))
1411                                         die("Log %s is corrupt.", logfile);
1412                         }
1413                         else {
1414                                 if (get_sha1_hex(rec + 41, logged_sha1))
1415                                         die("Log %s is corrupt.", logfile);
1416                                 if (hashcmp(logged_sha1, sha1)) {
1417                                         fprintf(stderr,
1418                                                 "warning: Log %s unexpectedly ended on %s.\n",
1419                                                 logfile, show_date(date, tz, DATE_RFC2822));
1420                                 }
1421                         }
1422                         munmap(log_mapped, mapsz);
1423                         return 0;
1424                 }
1425                 lastrec = rec;
1426                 if (cnt > 0)
1427                         cnt--;
1428         }
1429
1430         rec = logdata;
1431         while (rec < logend && *rec != '>' && *rec != '\n')
1432                 rec++;
1433         if (rec == logend || *rec == '\n')
1434                 die("Log %s is corrupt.", logfile);
1435         date = strtoul(rec + 1, &tz_c, 10);
1436         tz = strtoul(tz_c, NULL, 10);
1437         if (get_sha1_hex(logdata, sha1))
1438                 die("Log %s is corrupt.", logfile);
1439         if (is_null_sha1(sha1)) {
1440                 if (get_sha1_hex(logdata + 41, sha1))
1441                         die("Log %s is corrupt.", logfile);
1442         }
1443         if (msg)
1444                 *msg = ref_msg(logdata, logend);
1445         munmap(log_mapped, mapsz);
1446
1447         if (cutoff_time)
1448                 *cutoff_time = date;
1449         if (cutoff_tz)
1450                 *cutoff_tz = tz;
1451         if (cutoff_cnt)
1452                 *cutoff_cnt = reccnt;
1453         return 1;
1454 }
1455
1456 int for_each_reflog_ent(const char *ref, each_reflog_ent_fn fn, void *cb_data)
1457 {
1458         const char *logfile;
1459         FILE *logfp;
1460         char buf[1024];
1461         int ret = 0;
1462
1463         logfile = git_path("logs/%s", ref);
1464         logfp = fopen(logfile, "r");
1465         if (!logfp)
1466                 return -1;
1467         while (fgets(buf, sizeof(buf), logfp)) {
1468                 unsigned char osha1[20], nsha1[20];
1469                 char *email_end, *message;
1470                 unsigned long timestamp;
1471                 int len, tz;
1472
1473                 /* old SP new SP name <email> SP time TAB msg LF */
1474                 len = strlen(buf);
1475                 if (len < 83 || buf[len-1] != '\n' ||
1476                     get_sha1_hex(buf, osha1) || buf[40] != ' ' ||
1477                     get_sha1_hex(buf + 41, nsha1) || buf[81] != ' ' ||
1478                     !(email_end = strchr(buf + 82, '>')) ||
1479                     email_end[1] != ' ' ||
1480                     !(timestamp = strtoul(email_end + 2, &message, 10)) ||
1481                     !message || message[0] != ' ' ||
1482                     (message[1] != '+' && message[1] != '-') ||
1483                     !isdigit(message[2]) || !isdigit(message[3]) ||
1484                     !isdigit(message[4]) || !isdigit(message[5]))
1485                         continue; /* corrupt? */
1486                 email_end[1] = '\0';
1487                 tz = strtol(message + 1, NULL, 10);
1488                 if (message[6] != '\t')
1489                         message += 6;
1490                 else
1491                         message += 7;
1492                 ret = fn(osha1, nsha1, buf+82, timestamp, tz, message, cb_data);
1493                 if (ret)
1494                         break;
1495         }
1496         fclose(logfp);
1497         return ret;
1498 }
1499
1500 static int do_for_each_reflog(const char *base, each_ref_fn fn, void *cb_data)
1501 {
1502         DIR *dir = opendir(git_path("logs/%s", base));
1503         int retval = 0;
1504
1505         if (dir) {
1506                 struct dirent *de;
1507                 int baselen = strlen(base);
1508                 char *log = xmalloc(baselen + 257);
1509
1510                 memcpy(log, base, baselen);
1511                 if (baselen && base[baselen-1] != '/')
1512                         log[baselen++] = '/';
1513
1514                 while ((de = readdir(dir)) != NULL) {
1515                         struct stat st;
1516                         int namelen;
1517
1518                         if (de->d_name[0] == '.')
1519                                 continue;
1520                         namelen = strlen(de->d_name);
1521                         if (namelen > 255)
1522                                 continue;
1523                         if (has_extension(de->d_name, ".lock"))
1524                                 continue;
1525                         memcpy(log + baselen, de->d_name, namelen+1);
1526                         if (stat(git_path("logs/%s", log), &st) < 0)
1527                                 continue;
1528                         if (S_ISDIR(st.st_mode)) {
1529                                 retval = do_for_each_reflog(log, fn, cb_data);
1530                         } else {
1531                                 unsigned char sha1[20];
1532                                 if (!resolve_ref(log, sha1, 0, NULL))
1533                                         retval = error("bad ref for %s", log);
1534                                 else
1535                                         retval = fn(log, sha1, 0, cb_data);
1536                         }
1537                         if (retval)
1538                                 break;
1539                 }
1540                 free(log);
1541                 closedir(dir);
1542         }
1543         else if (*base)
1544                 return errno;
1545         return retval;
1546 }
1547
1548 int for_each_reflog(each_ref_fn fn, void *cb_data)
1549 {
1550         return do_for_each_reflog("", fn, cb_data);
1551 }
1552
1553 int update_ref(const char *action, const char *refname,
1554                 const unsigned char *sha1, const unsigned char *oldval,
1555                 int flags, enum action_on_err onerr)
1556 {
1557         static struct ref_lock *lock;
1558         lock = lock_any_ref_for_update(refname, oldval, flags);
1559         if (!lock) {
1560                 const char *str = "Cannot lock the ref '%s'.";
1561                 switch (onerr) {
1562                 case MSG_ON_ERR: error(str, refname); break;
1563                 case DIE_ON_ERR: die(str, refname); break;
1564                 case QUIET_ON_ERR: break;
1565                 }
1566                 return 1;
1567         }
1568         if (write_ref_sha1(lock, sha1, action) < 0) {
1569                 const char *str = "Cannot update the ref '%s'.";
1570                 switch (onerr) {
1571                 case MSG_ON_ERR: error(str, refname); break;
1572                 case DIE_ON_ERR: die(str, refname); break;
1573                 case QUIET_ON_ERR: break;
1574                 }
1575                 return 1;
1576         }
1577         return 0;
1578 }
1579
1580 struct ref *find_ref_by_name(struct ref *list, const char *name)
1581 {
1582         for ( ; list; list = list->next)
1583                 if (!strcmp(list->name, name))
1584                         return list;
1585         return NULL;
1586 }