refs.c

   1 #include "cache.h"
   2 #include "refs.h"
   3 #include "object.h"
   4 #include "tag.h"
   5 #include "dir.h"
   6
   7 /* ISSYMREF=01 and ISPACKED=02 are public interfaces */
   8 #define REF_KNOWS_PEELED 04
   9
  10 struct ref_list {
  11         struct ref_list *next;
  12         unsigned char flag; /* ISSYMREF? ISPACKED? */
  13         unsigned char sha1[20];
  14         unsigned char peeled[20];
  15         char name[FLEX_ARRAY];
  16 };
  17
  18 static const char *parse_ref_line(char *line, unsigned char *sha1)
  19 {
  20         /*
  21          * 42: the answer to everything.
  22          *
  23          * In this case, it happens to be the answer to
  24          *  40 (length of sha1 hex representation)
  25          *  +1 (space in between hex and name)
  26          *  +1 (newline at the end of the line)
  27          */
  28         int len = strlen(line) - 42;
  29
  30         if (len <= 0)
  31                 return NULL;
  32         if (get_sha1_hex(line, sha1) < 0)
  33                 return NULL;
  34         if (!isspace(line[40]))
  35                 return NULL;
  36         line += 41;
  37         if (isspace(*line))
  38                 return NULL;
  39         if (line[len] != '\n')
  40                 return NULL;
  41         line[len] = 0;
  42
  43         return line;
  44 }
  45
  46 static struct ref_list *add_ref(const char *name, const unsigned char *sha1,
  47                                 int flag, struct ref_list *list,
  48                                 struct ref_list **new_entry)
  49 {
  50         int len;
  51         struct ref_list *entry;
  52
  53         /* Allocate it and add it in.. */
  54         len = strlen(name) + 1;
  55         entry = xmalloc(sizeof(struct ref_list) + len);
  56         hashcpy(entry->sha1, sha1);
  57         hashclr(entry->peeled);
  58         memcpy(entry->name, name, len);
  59         entry->flag = flag;
  60         entry->next = list;
  61         if (new_entry)
  62                 *new_entry = entry;
  63         return entry;
  64 }
  65
  66 /* merge sort the ref list */
  67 static struct ref_list *sort_ref_list(struct ref_list *list)
  68 {
  69         int psize, qsize, last_merge_count, cmp;
  70         struct ref_list *p, *q, *l, *e;
  71         struct ref_list *new_list = list;
  72         int k = 1;
  73         int merge_count = 0;
  74
  75         if (!list)
  76                 return list;
  77
  78         do {
  79                 last_merge_count = merge_count;
  80                 merge_count = 0;
  81
  82                 psize = 0;
  83
  84                 p = new_list;
  85                 q = new_list;
  86                 new_list = NULL;
  87                 l = NULL;
  88
  89                 while (p) {
  90                         merge_count++;
  91
  92                         while (psize < k && q->next) {
  93                                 q = q->next;
  94                                 psize++;
  95                         }
  96                         qsize = k;
  97
  98                         while ((psize > 0) || (qsize > 0 && q)) {
  99                                 if (qsize == 0 || !q) {
 100                                         e = p;
 101                                         p = p->next;
 102                                         psize--;
 103                                 } else if (psize == 0) {
 104                                         e = q;
 105                                         q = q->next;
 106                                         qsize--;
 107                                 } else {
 108                                         cmp = strcmp(q->name, p->name);
 109                                         if (cmp < 0) {
 110                                                 e = q;
 111                                                 q = q->next;
 112                                                 qsize--;
 113                                         } else if (cmp > 0) {
 114                                                 e = p;
 115                                                 p = p->next;
 116                                                 psize--;
 117                                         } else {
 118                                                 if (hashcmp(q->sha1, p->sha1))
 119                                                         die("Duplicated ref, and SHA1s don't match: %s",
 120                                                             q->name);
 121                                                 warning("Duplicated ref: %s", q->name);
 122                                                 e = q;
 123                                                 q = q->next;
 124                                                 qsize--;
 125                                                 free(e);
 126                                                 e = p;
 127                                                 p = p->next;
 128                                                 psize--;
 129                                         }
 130                                 }
 131
 132                                 e->next = NULL;
 133
 134                                 if (l)
 135                                         l->next = e;
 136                                 if (!new_list)
 137                                         new_list = e;
 138                                 l = e;
 139                         }
 140
 141                         p = q;
 142                 };
 143
 144                 k = k * 2;
 145         } while ((last_merge_count != merge_count) || (last_merge_count != 1));
 146
 147         return new_list;
 148 }
 149
 150 /*
 151  * Future: need to be in "struct repository"
 152  * when doing a full libification.
 153  */
 154 static struct cached_refs {
 155         char did_loose;
 156         char did_packed;
 157         struct ref_list *loose;
 158         struct ref_list *packed;
 159 } cached_refs;
 160 static struct ref_list *current_ref;
 161
 162 static struct ref_list *extra_refs;
 163
 164 static void free_ref_list(struct ref_list *list)
 165 {
 166         struct ref_list *next;
 167         for ( ; list; list = next) {
 168                 next = list->next;
 169                 free(list);
 170         }
 171 }
 172
 173 static void invalidate_cached_refs(void)
 174 {
 175         struct cached_refs *ca = &cached_refs;
 176
 177         if (ca->did_loose && ca->loose)
 178                 free_ref_list(ca->loose);
 179         if (ca->did_packed && ca->packed)
 180                 free_ref_list(ca->packed);
 181         ca->loose = ca->packed = NULL;
 182         ca->did_loose = ca->did_packed = 0;
 183 }
 184
 185 static void read_packed_refs(FILE *f, struct cached_refs *cached_refs)
 186 {
 187         struct ref_list *list = NULL;
 188         struct ref_list *last = NULL;
 189         char refline[PATH_MAX];
 190         int flag = REF_ISPACKED;
 191
 192         while (fgets(refline, sizeof(refline), f)) {
 193                 unsigned char sha1[20];
 194                 const char *name;
 195                 static const char header[] = "# pack-refs with:";
 196
 197                 if (!strncmp(refline, header, sizeof(header)-1)) {
 198                         const char *traits = refline + sizeof(header) - 1;
 199                         if (strstr(traits, " peeled "))
 200                                 flag |= REF_KNOWS_PEELED;
 201                         /* perhaps other traits later as well */
 202                         continue;
 203                 }
 204
 205                 name = parse_ref_line(refline, sha1);
 206                 if (name) {
 207                         list = add_ref(name, sha1, flag, list, &last);
 208                         continue;
 209                 }
 210                 if (last &&
 211                     refline[0] == '^' &&
 212                     strlen(refline) == 42 &&
 213                     refline[41] == '\n' &&
 214                     !get_sha1_hex(refline + 1, sha1))
 215                         hashcpy(last->peeled, sha1);
 216         }
 217         cached_refs->packed = sort_ref_list(list);
 218 }
 219
 220 void add_extra_ref(const char *name, const unsigned char *sha1, int flag)
 221 {
 222         extra_refs = add_ref(name, sha1, flag, extra_refs, NULL);
 223 }
 224
 225 void clear_extra_refs(void)
 226 {
 227         free_ref_list(extra_refs);
 228         extra_refs = NULL;
 229 }
 230
 231 static struct ref_list *get_packed_refs(void)
 232 {
 233         if (!cached_refs.did_packed) {
 234                 FILE *f = fopen(git_path("packed-refs"), "r");
 235                 cached_refs.packed = NULL;
 236                 if (f) {
 237                         read_packed_refs(f, &cached_refs);
 238                         fclose(f);
 239                 }
 240                 cached_refs.did_packed = 1;
 241         }
 242         return cached_refs.packed;
 243 }
 244
 245 static struct ref_list *get_ref_dir(const char *base, struct ref_list *list)
 246 {
 247         DIR *dir = opendir(git_path("%s", base));
 248
 249         if (dir) {
 250                 struct dirent *de;
 251                 int baselen = strlen(base);
 252                 char *ref = xmalloc(baselen + 257);
 253
 254                 memcpy(ref, base, baselen);
 255                 if (baselen && base[baselen-1] != '/')
 256                         ref[baselen++] = '/';
 257
 258                 while ((de = readdir(dir)) != NULL) {
 259                         unsigned char sha1[20];
 260                         struct stat st;
 261                         int flag;
 262                         int namelen;
 263
 264                         if (de->d_name[0] == '.')
 265                                 continue;
 266                         namelen = strlen(de->d_name);
 267                         if (namelen > 255)
 268                                 continue;
 269                         if (has_extension(de->d_name, ".lock"))
 270                                 continue;
 271                         memcpy(ref + baselen, de->d_name, namelen+1);
 272                         if (stat(git_path("%s", ref), &st) < 0)
 273                                 continue;
 274                         if (S_ISDIR(st.st_mode)) {
 275                                 list = get_ref_dir(ref, list);
 276                                 continue;
 277                         }
 278                         if (!resolve_ref(ref, sha1, 1, &flag))
 279                                 hashclr(sha1);
 280                         list = add_ref(ref, sha1, flag, list, NULL);
 281                 }
 282                 free(ref);
 283                 closedir(dir);
 284         }
 285         return sort_ref_list(list);
 286 }
 287
 288 struct warn_if_dangling_data {
 289         FILE *fp;
 290         const char *refname;
 291         const char *msg_fmt;
 292 };
 293
 294 static int warn_if_dangling_symref(const char *refname, const unsigned char *sha1,
 295                                    int flags, void *cb_data)
 296 {
 297         struct warn_if_dangling_data *d = cb_data;
 298         const char *resolves_to;
 299         unsigned char junk[20];
 300
 301         if (!(flags & REF_ISSYMREF))
 302                 return 0;
 303
 304         resolves_to = resolve_ref(refname, junk, 0, NULL);
 305         if (!resolves_to || strcmp(resolves_to, d->refname))
 306                 return 0;
 307
 308         fprintf(d->fp, d->msg_fmt, refname);
 309         return 0;
 310 }
 311
 312 void warn_dangling_symref(FILE *fp, const char *msg_fmt, const char *refname)
 313 {
 314         struct warn_if_dangling_data data = { fp, refname, msg_fmt };
 315         for_each_rawref(warn_if_dangling_symref, &data);
 316 }
 317
 318 static struct ref_list *get_loose_refs(void)
 319 {
 320         if (!cached_refs.did_loose) {
 321                 cached_refs.loose = get_ref_dir("refs", NULL);
 322                 cached_refs.did_loose = 1;
 323         }
 324         return cached_refs.loose;
 325 }
 326
 327 /* We allow "recursive" symbolic refs. Only within reason, though */
 328 #define MAXDEPTH 5
 329 #define MAXREFLEN (1024)
 330
 331 static int resolve_gitlink_packed_ref(char *name, int pathlen, const char *refname, unsigned char *result)
 332 {
 333         FILE *f;
 334         struct cached_refs refs;
 335         struct ref_list *ref;
 336         int retval;
 337
 338         strcpy(name + pathlen, "packed-refs");
 339         f = fopen(name, "r");
 340         if (!f)
 341                 return -1;
 342         read_packed_refs(f, &refs);
 343         fclose(f);
 344         ref = refs.packed;
 345         retval = -1;
 346         while (ref) {
 347                 if (!strcmp(ref->name, refname)) {
 348                         retval = 0;
 349                         memcpy(result, ref->sha1, 20);
 350                         break;
 351                 }
 352                 ref = ref->next;
 353         }
 354         free_ref_list(refs.packed);
 355         return retval;
 356 }
 357
 358 static int resolve_gitlink_ref_recursive(char *name, int pathlen, const char *refname, unsigned char *result, int recursion)
 359 {
 360         int fd, len = strlen(refname);
 361         char buffer[128], *p;
 362
 363         if (recursion > MAXDEPTH || len > MAXREFLEN)
 364                 return -1;
 365         memcpy(name + pathlen, refname, len+1);
 366         fd = open(name, O_RDONLY);
 367         if (fd < 0)
 368                 return resolve_gitlink_packed_ref(name, pathlen, refname, result);
 369
 370         len = read(fd, buffer, sizeof(buffer)-1);
 371         close(fd);
 372         if (len < 0)
 373                 return -1;
 374         while (len && isspace(buffer[len-1]))
 375                 len--;
 376         buffer[len] = 0;
 377
 378         /* Was it a detached head or an old-fashioned symlink? */
 379         if (!get_sha1_hex(buffer, result))
 380                 return 0;
 381
 382         /* Symref? */
 383         if (strncmp(buffer, "ref:", 4))
 384                 return -1;
 385         p = buffer + 4;
 386         while (isspace(*p))
 387                 p++;
 388
 389         return resolve_gitlink_ref_recursive(name, pathlen, p, result, recursion+1);
 390 }
 391
 392 int resolve_gitlink_ref(const char *path, const char *refname, unsigned char *result)
 393 {
 394         int len = strlen(path), retval;
 395         char *gitdir;
 396         const char *tmp;
 397
 398         while (len && path[len-1] == '/')
 399                 len--;
 400         if (!len)
 401                 return -1;
 402         gitdir = xmalloc(len + MAXREFLEN + 8);
 403         memcpy(gitdir, path, len);
 404         memcpy(gitdir + len, "/.git", 6);
 405         len += 5;
 406
 407         tmp = read_gitfile_gently(gitdir);
 408         if (tmp) {
 409                 free(gitdir);
 410                 len = strlen(tmp);
 411                 gitdir = xmalloc(len + MAXREFLEN + 3);
 412                 memcpy(gitdir, tmp, len);
 413         }
 414         gitdir[len] = '/';
 415         gitdir[++len] = '\0';
 416         retval = resolve_gitlink_ref_recursive(gitdir, len, refname, result, 0);
 417         free(gitdir);
 418         return retval;
 419 }
 420
 421 /*
 422  * If the "reading" argument is set, this function finds out what _object_
 423  * the ref points at by "reading" the ref.  The ref, if it is not symbolic,
 424  * has to exist, and if it is symbolic, it has to point at an existing ref,
 425  * because the "read" goes through the symref to the ref it points at.
 426  *
 427  * The access that is not "reading" may often be "writing", but does not
 428  * have to; it can be merely checking _where it leads to_. If it is a
 429  * prelude to "writing" to the ref, a write to a symref that points at
 430  * yet-to-be-born ref will create the real ref pointed by the symref.
 431  * reading=0 allows the caller to check where such a symref leads to.
 432  */
 433 const char *resolve_ref(const char *ref, unsigned char *sha1, int reading, int *flag)
 434 {
 435         int depth = MAXDEPTH;
 436         ssize_t len;
 437         char buffer[256];
 438         static char ref_buffer[256];
 439
 440         if (flag)
 441                 *flag = 0;
 442
 443         for (;;) {
 444                 char path[PATH_MAX];
 445                 struct stat st;
 446                 char *buf;
 447                 int fd;
 448
 449                 if (--depth < 0)
 450                         return NULL;
 451
 452                 git_snpath(path, sizeof(path), "%s", ref);
 453                 /* Special case: non-existing file. */
 454                 if (lstat(path, &st) < 0) {
 455                         struct ref_list *list = get_packed_refs();
 456                         while (list) {
 457                                 if (!strcmp(ref, list->name)) {
 458                                         hashcpy(sha1, list->sha1);
 459                                         if (flag)
 460                                                 *flag |= REF_ISPACKED;
 461                                         return ref;
 462                                 }
 463                                 list = list->next;
 464                         }
 465                         if (reading || errno != ENOENT)
 466                                 return NULL;
 467                         hashclr(sha1);
 468                         return ref;
 469                 }
 470
 471                 /* Follow "normalized" - ie "refs/.." symlinks by hand */
 472                 if (S_ISLNK(st.st_mode)) {
 473                         len = readlink(path, buffer, sizeof(buffer)-1);
 474                         if (len >= 5 && !memcmp("refs/", buffer, 5)) {
 475                                 buffer[len] = 0;
 476                                 strcpy(ref_buffer, buffer);
 477                                 ref = ref_buffer;
 478                                 if (flag)
 479                                         *flag |= REF_ISSYMREF;
 480                                 continue;
 481                         }
 482                 }
 483
 484                 /* Is it a directory? */
 485                 if (S_ISDIR(st.st_mode)) {
 486                         errno = EISDIR;
 487                         return NULL;
 488                 }
 489
 490                 /*
 491                  * Anything else, just open it and try to use it as
 492                  * a ref
 493                  */
 494                 fd = open(path, O_RDONLY);
 495                 if (fd < 0)
 496                         return NULL;
 497                 len = read_in_full(fd, buffer, sizeof(buffer)-1);
 498                 close(fd);
 499
 500                 /*
 501                  * Is it a symbolic ref?
 502                  */
 503                 if (len < 4 || memcmp("ref:", buffer, 4))
 504                         break;
 505                 buf = buffer + 4;
 506                 len -= 4;
 507                 while (len && isspace(*buf))
 508                         buf++, len--;
 509                 while (len && isspace(buf[len-1]))
 510                         len--;
 511                 buf[len] = 0;
 512                 memcpy(ref_buffer, buf, len + 1);
 513                 ref = ref_buffer;
 514                 if (flag)
 515                         *flag |= REF_ISSYMREF;
 516         }
 517         if (len < 40 || get_sha1_hex(buffer, sha1))
 518                 return NULL;
 519         return ref;
 520 }
 521
 522 int read_ref(const char *ref, unsigned char *sha1)
 523 {
 524         if (resolve_ref(ref, sha1, 1, NULL))
 525                 return 0;
 526         return -1;
 527 }
 528
 529 #define DO_FOR_EACH_INCLUDE_BROKEN 01
 530 static int do_one_ref(const char *base, each_ref_fn fn, int trim,
 531                       int flags, void *cb_data, struct ref_list *entry)
 532 {
 533         if (strncmp(base, entry->name, trim))
 534                 return 0;
 535         /* Is this a "negative ref" that represents a deleted ref? */
 536         if (is_null_sha1(entry->sha1))
 537                 return 0;
 538         if (!(flags & DO_FOR_EACH_INCLUDE_BROKEN)) {
 539                 if (!has_sha1_file(entry->sha1)) {
 540                         error("%s does not point to a valid object!", entry->name);
 541                         return 0;
 542                 }
 543         }
 544         current_ref = entry;
 545         return fn(entry->name + trim, entry->sha1, entry->flag, cb_data);
 546 }
 547
 548 int peel_ref(const char *ref, unsigned char *sha1)
 549 {
 550         int flag;
 551         unsigned char base[20];
 552         struct object *o;
 553
 554         if (current_ref && (current_ref->name == ref
 555                 || !strcmp(current_ref->name, ref))) {
 556                 if (current_ref->flag & REF_KNOWS_PEELED) {
 557                         hashcpy(sha1, current_ref->peeled);
 558                         return 0;
 559                 }
 560                 hashcpy(base, current_ref->sha1);
 561                 goto fallback;
 562         }
 563
 564         if (!resolve_ref(ref, base, 1, &flag))
 565                 return -1;
 566
 567         if ((flag & REF_ISPACKED)) {
 568                 struct ref_list *list = get_packed_refs();
 569
 570                 while (list) {
 571                         if (!strcmp(list->name, ref)) {
 572                                 if (list->flag & REF_KNOWS_PEELED) {
 573                                         hashcpy(sha1, list->peeled);
 574                                         return 0;
 575                                 }
 576                                 /* older pack-refs did not leave peeled ones */
 577                                 break;
 578                         }
 579                         list = list->next;
 580                 }
 581         }
 582
 583 fallback:
 584         o = parse_object(base);
 585         if (o && o->type == OBJ_TAG) {
 586                 o = deref_tag(o, ref, 0);
 587                 if (o) {
 588                         hashcpy(sha1, o->sha1);
 589                         return 0;
 590                 }
 591         }
 592         return -1;
 593 }
 594
 595 static int do_for_each_ref(const char *base, each_ref_fn fn, int trim,
 596                            int flags, void *cb_data)
 597 {
 598         int retval = 0;
 599         struct ref_list *packed = get_packed_refs();
 600         struct ref_list *loose = get_loose_refs();
 601
 602         struct ref_list *extra;
 603
 604         for (extra = extra_refs; extra; extra = extra->next)
 605                 retval = do_one_ref(base, fn, trim, flags, cb_data, extra);
 606
 607         while (packed && loose) {
 608                 struct ref_list *entry;
 609                 int cmp = strcmp(packed->name, loose->name);
 610                 if (!cmp) {
 611                         packed = packed->next;
 612                         continue;
 613                 }
 614                 if (cmp > 0) {
 615                         entry = loose;
 616                         loose = loose->next;
 617                 } else {
 618                         entry = packed;
 619                         packed = packed->next;
 620                 }
 621                 retval = do_one_ref(base, fn, trim, flags, cb_data, entry);
 622                 if (retval)
 623                         goto end_each;
 624         }
 625
 626         for (packed = packed ? packed : loose; packed; packed = packed->next) {
 627                 retval = do_one_ref(base, fn, trim, flags, cb_data, packed);
 628                 if (retval)
 629                         goto end_each;
 630         }
 631
 632 end_each:
 633         current_ref = NULL;
 634         return retval;
 635 }
 636
 637 int head_ref(each_ref_fn fn, void *cb_data)
 638 {
 639         unsigned char sha1[20];
 640         int flag;
 641
 642         if (resolve_ref("HEAD", sha1, 1, &flag))
 643                 return fn("HEAD", sha1, flag, cb_data);
 644         return 0;
 645 }
 646
 647 int for_each_ref(each_ref_fn fn, void *cb_data)
 648 {
 649         return do_for_each_ref("refs/", fn, 0, 0, cb_data);
 650 }
 651
 652 int for_each_ref_in(const char *prefix, each_ref_fn fn, void *cb_data)
 653 {
 654         return do_for_each_ref(prefix, fn, strlen(prefix), 0, cb_data);
 655 }
 656
 657 int for_each_tag_ref(each_ref_fn fn, void *cb_data)
 658 {
 659         return for_each_ref_in("refs/tags/", fn, cb_data);
 660 }
 661
 662 int for_each_branch_ref(each_ref_fn fn, void *cb_data)
 663 {
 664         return for_each_ref_in("refs/heads/", fn, cb_data);
 665 }
 666
 667 int for_each_remote_ref(each_ref_fn fn, void *cb_data)
 668 {
 669         return for_each_ref_in("refs/remotes/", fn, cb_data);
 670 }
 671
 672 int for_each_replace_ref(each_ref_fn fn, void *cb_data)
 673 {
 674         return do_for_each_ref("refs/replace/", fn, 13, 0, cb_data);
 675 }
 676
 677 int for_each_rawref(each_ref_fn fn, void *cb_data)
 678 {
 679         return do_for_each_ref("refs/", fn, 0,
 680                                DO_FOR_EACH_INCLUDE_BROKEN, cb_data);
 681 }
 682
 683 /*
 684  * Make sure "ref" is something reasonable to have under ".git/refs/";
 685  * We do not like it if:
 686  *
 687  * - any path component of it begins with ".", or
 688  * - it has double dots "..", or
 689  * - it has ASCII control character, "~", "^", ":" or SP, anywhere, or
 690  * - it ends with a "/".
 691  * - it ends with ".lock"
 692  * - it contains a "\" (backslash)
 693  */
 694
 695 static inline int bad_ref_char(int ch)
 696 {
 697         if (((unsigned) ch) <= ' ' ||
 698             ch == '~' || ch == '^' || ch == ':' || ch == '\\')
 699                 return 1;
 700         /* 2.13 Pattern Matching Notation */
 701         if (ch == '?' || ch == '[') /* Unsupported */
 702                 return 1;
 703         if (ch == '*') /* Supported at the end */
 704                 return 2;
 705         return 0;
 706 }
 707
 708 int check_ref_format(const char *ref)
 709 {
 710         int ch, level, bad_type, last;
 711         int ret = CHECK_REF_FORMAT_OK;
 712         const char *cp = ref;
 713
 714         level = 0;
 715         while (1) {
 716                 while ((ch = *cp++) == '/')
 717                         ; /* tolerate duplicated slashes */
 718                 if (!ch)
 719                         /* should not end with slashes */
 720                         return CHECK_REF_FORMAT_ERROR;
 721
 722                 /* we are at the beginning of the path component */
 723                 if (ch == '.')
 724                         return CHECK_REF_FORMAT_ERROR;
 725                 bad_type = bad_ref_char(ch);
 726                 if (bad_type) {
 727                         if (bad_type == 2 && (!*cp || *cp == '/') &&
 728                             ret == CHECK_REF_FORMAT_OK)
 729                                 ret = CHECK_REF_FORMAT_WILDCARD;
 730                         else
 731                                 return CHECK_REF_FORMAT_ERROR;
 732                 }
 733
 734                 last = ch;
 735                 /* scan the rest of the path component */
 736                 while ((ch = *cp++) != 0) {
 737                         bad_type = bad_ref_char(ch);
 738                         if (bad_type)
 739                                 return CHECK_REF_FORMAT_ERROR;
 740                         if (ch == '/')
 741                                 break;
 742                         if (last == '.' && ch == '.')
 743                                 return CHECK_REF_FORMAT_ERROR;
 744                         if (last == '@' && ch == '{')
 745                                 return CHECK_REF_FORMAT_ERROR;
 746                         last = ch;
 747                 }
 748                 level++;
 749                 if (!ch) {
 750                         if (ref <= cp - 2 && cp[-2] == '.')
 751                                 return CHECK_REF_FORMAT_ERROR;
 752                         if (level < 2)
 753                                 return CHECK_REF_FORMAT_ONELEVEL;
 754                         if (has_extension(ref, ".lock"))
 755                                 return CHECK_REF_FORMAT_ERROR;
 756                         return ret;
 757                 }
 758         }
 759 }
 760
 761 const char *prettify_refname(const char *name)
 762 {
 763         return name + (
 764                 !prefixcmp(name, "refs/heads/") ? 11 :
 765                 !prefixcmp(name, "refs/tags/") ? 10 :
 766                 !prefixcmp(name, "refs/remotes/") ? 13 :
 767                 0);
 768 }
 769
 770 const char *ref_rev_parse_rules[] = {
 771         "%.*s",
 772         "refs/%.*s",
 773         "refs/tags/%.*s",
 774         "refs/heads/%.*s",
 775         "refs/remotes/%.*s",
 776         "refs/remotes/%.*s/HEAD",
 777         NULL
 778 };
 779
 780 const char *ref_fetch_rules[] = {
 781         "%.*s",
 782         "refs/%.*s",
 783         "refs/heads/%.*s",
 784         NULL
 785 };
 786
 787 int refname_match(const char *abbrev_name, const char *full_name, const char **rules)
 788 {
 789         const char **p;
 790         const int abbrev_name_len = strlen(abbrev_name);
 791
 792         for (p = rules; *p; p++) {
 793                 if (!strcmp(full_name, mkpath(*p, abbrev_name_len, abbrev_name))) {
 794                         return 1;
 795                 }
 796         }
 797
 798         return 0;
 799 }
 800
 801 static struct ref_lock *verify_lock(struct ref_lock *lock,
 802         const unsigned char *old_sha1, int mustexist)
 803 {
 804         if (!resolve_ref(lock->ref_name, lock->old_sha1, mustexist, NULL)) {
 805                 error("Can't verify ref %s", lock->ref_name);
 806                 unlock_ref(lock);
 807                 return NULL;
 808         }
 809         if (hashcmp(lock->old_sha1, old_sha1)) {
 810                 error("Ref %s is at %s but expected %s", lock->ref_name,
 811                         sha1_to_hex(lock->old_sha1), sha1_to_hex(old_sha1));
 812                 unlock_ref(lock);
 813                 return NULL;
 814         }
 815         return lock;
 816 }
 817
 818 static int remove_empty_directories(const char *file)
 819 {
 820         /* we want to create a file but there is a directory there;
 821          * if that is an empty directory (or a directory that contains
 822          * only empty directories), remove them.
 823          */
 824         struct strbuf path;
 825         int result;
 826
 827         strbuf_init(&path, 20);
 828         strbuf_addstr(&path, file);
 829
 830         result = remove_dir_recursively(&path, REMOVE_DIR_EMPTY_ONLY);
 831
 832         strbuf_release(&path);
 833
 834         return result;
 835 }
 836
 837 static int is_refname_available(const char *ref, const char *oldref,
 838                                 struct ref_list *list, int quiet)
 839 {
 840         int namlen = strlen(ref); /* e.g. 'foo/bar' */
 841         while (list) {
 842                 /* list->name could be 'foo' or 'foo/bar/baz' */
 843                 if (!oldref || strcmp(oldref, list->name)) {
 844                         int len = strlen(list->name);
 845                         int cmplen = (namlen < len) ? namlen : len;
 846                         const char *lead = (namlen < len) ? list->name : ref;
 847                         if (!strncmp(ref, list->name, cmplen) &&
 848                             lead[cmplen] == '/') {
 849                                 if (!quiet)
 850                                         error("'%s' exists; cannot create '%s'",
 851                                               list->name, ref);
 852                                 return 0;
 853                         }
 854                 }
 855                 list = list->next;
 856         }
 857         return 1;
 858 }
 859
 860 static struct ref_lock *lock_ref_sha1_basic(const char *ref, const unsigned char *old_sha1, int flags, int *type_p)
 861 {
 862         char *ref_file;
 863         const char *orig_ref = ref;
 864         struct ref_lock *lock;
 865         int last_errno = 0;
 866         int type, lflags;
 867         int mustexist = (old_sha1 && !is_null_sha1(old_sha1));
 868         int missing = 0;
 869
 870         lock = xcalloc(1, sizeof(struct ref_lock));
 871         lock->lock_fd = -1;
 872
 873         ref = resolve_ref(ref, lock->old_sha1, mustexist, &type);
 874         if (!ref && errno == EISDIR) {
 875                 /* we are trying to lock foo but we used to
 876                  * have foo/bar which now does not exist;
 877                  * it is normal for the empty directory 'foo'
 878                  * to remain.
 879                  */
 880                 ref_file = git_path("%s", orig_ref);
 881                 if (remove_empty_directories(ref_file)) {
 882                         last_errno = errno;
 883                         error("there are still refs under '%s'", orig_ref);
 884                         goto error_return;
 885                 }
 886                 ref = resolve_ref(orig_ref, lock->old_sha1, mustexist, &type);
 887         }
 888         if (type_p)
 889             *type_p = type;
 890         if (!ref) {
 891                 last_errno = errno;
 892                 error("unable to resolve reference %s: %s",
 893                         orig_ref, strerror(errno));
 894                 goto error_return;
 895         }
 896         missing = is_null_sha1(lock->old_sha1);
 897         /* When the ref did not exist and we are creating it,
 898          * make sure there is no existing ref that is packed
 899          * whose name begins with our refname, nor a ref whose
 900          * name is a proper prefix of our refname.
 901          */
 902         if (missing &&
 903              !is_refname_available(ref, NULL, get_packed_refs(), 0)) {
 904                 last_errno = ENOTDIR;
 905                 goto error_return;
 906         }
 907
 908         lock->lk = xcalloc(1, sizeof(struct lock_file));
 909
 910         lflags = LOCK_DIE_ON_ERROR;
 911         if (flags & REF_NODEREF) {
 912                 ref = orig_ref;
 913                 lflags |= LOCK_NODEREF;
 914         }
 915         lock->ref_name = xstrdup(ref);
 916         lock->orig_ref_name = xstrdup(orig_ref);
 917         ref_file = git_path("%s", ref);
 918         if (missing)
 919                 lock->force_write = 1;
 920         if ((flags & REF_NODEREF) && (type & REF_ISSYMREF))
 921                 lock->force_write = 1;
 922
 923         if (safe_create_leading_directories(ref_file)) {
 924                 last_errno = errno;
 925                 error("unable to create directory for %s", ref_file);
 926                 goto error_return;
 927         }
 928
 929         lock->lock_fd = hold_lock_file_for_update(lock->lk, ref_file, lflags);
 930         return old_sha1 ? verify_lock(lock, old_sha1, mustexist) : lock;
 931
 932  error_return:
 933         unlock_ref(lock);
 934         errno = last_errno;
 935         return NULL;
 936 }
 937
 938 struct ref_lock *lock_ref_sha1(const char *ref, const unsigned char *old_sha1)
 939 {
 940         char refpath[PATH_MAX];
 941         if (check_ref_format(ref))
 942                 return NULL;
 943         strcpy(refpath, mkpath("refs/%s", ref));
 944         return lock_ref_sha1_basic(refpath, old_sha1, 0, NULL);
 945 }
 946
 947 struct ref_lock *lock_any_ref_for_update(const char *ref, const unsigned char *old_sha1, int flags)
 948 {
 949         switch (check_ref_format(ref)) {
 950         default:
 951                 return NULL;
 952         case 0:
 953         case CHECK_REF_FORMAT_ONELEVEL:
 954                 return lock_ref_sha1_basic(ref, old_sha1, flags, NULL);
 955         }
 956 }
 957
 958 static struct lock_file packlock;
 959
 960 static int repack_without_ref(const char *refname)
 961 {
 962         struct ref_list *list, *packed_ref_list;
 963         int fd;
 964         int found = 0;
 965
 966         packed_ref_list = get_packed_refs();
 967         for (list = packed_ref_list; list; list = list->next) {
 968                 if (!strcmp(refname, list->name)) {
 969                         found = 1;
 970                         break;
 971                 }
 972         }
 973         if (!found)
 974                 return 0;
 975         fd = hold_lock_file_for_update(&packlock, git_path("packed-refs"), 0);
 976         if (fd < 0) {
 977                 unable_to_lock_error(git_path("packed-refs"), errno);
 978                 return error("cannot delete '%s' from packed refs", refname);
 979         }
 980
 981         for (list = packed_ref_list; list; list = list->next) {
 982                 char line[PATH_MAX + 100];
 983                 int len;
 984
 985                 if (!strcmp(refname, list->name))
 986                         continue;
 987                 len = snprintf(line, sizeof(line), "%s %s\n",
 988                                sha1_to_hex(list->sha1), list->name);
 989                 /* this should not happen but just being defensive */
 990                 if (len > sizeof(line))
 991                         die("too long a refname '%s'", list->name);
 992                 write_or_die(fd, line, len);
 993         }
 994         return commit_lock_file(&packlock);
 995 }
 996
 997 int delete_ref(const char *refname, const unsigned char *sha1, int delopt)
 998 {
 999         struct ref_lock *lock;
1000         int err, i = 0, ret = 0, flag = 0;
1001
1002         lock = lock_ref_sha1_basic(refname, sha1, 0, &flag);
1003         if (!lock)
1004                 return 1;
1005         if (!(flag & REF_ISPACKED) || flag & REF_ISSYMREF) {
1006                 /* loose */
1007                 const char *path;
1008
1009                 if (!(delopt & REF_NODEREF)) {
1010                         i = strlen(lock->lk->filename) - 5; /* .lock */
1011                         lock->lk->filename[i] = 0;
1012                         path = lock->lk->filename;
1013                 } else {
1014                         path = git_path("%s", refname);
1015                 }
1016                 err = unlink_or_warn(path);
1017                 if (err && errno != ENOENT)
1018                         ret = 1;
1019
1020                 if (!(delopt & REF_NODEREF))
1021                         lock->lk->filename[i] = '.';
1022         }
1023         /* removing the loose one could have resurrected an earlier
1024          * packed one.  Also, if it was not loose we need to repack
1025          * without it.
1026          */
1027         ret |= repack_without_ref(refname);
1028
1029         unlink_or_warn(git_path("logs/%s", lock->ref_name));
1030         invalidate_cached_refs();
1031         unlock_ref(lock);
1032         return ret;
1033 }
1034
1035 int rename_ref(const char *oldref, const char *newref, const char *logmsg)
1036 {
1037         static const char renamed_ref[] = "RENAMED-REF";
1038         unsigned char sha1[20], orig_sha1[20];
1039         int flag = 0, logmoved = 0;
1040         struct ref_lock *lock;
1041         struct stat loginfo;
1042         int log = !lstat(git_path("logs/%s", oldref), &loginfo);
1043         const char *symref = NULL;
1044
1045         if (log && S_ISLNK(loginfo.st_mode))
1046                 return error("reflog for %s is a symlink", oldref);
1047
1048         symref = resolve_ref(oldref, orig_sha1, 1, &flag);
1049         if (flag & REF_ISSYMREF)
1050                 return error("refname %s is a symbolic ref, renaming it is not supported",
1051                         oldref);
1052         if (!symref)
1053                 return error("refname %s not found", oldref);
1054
1055         if (!is_refname_available(newref, oldref, get_packed_refs(), 0))
1056                 return 1;
1057
1058         if (!is_refname_available(newref, oldref, get_loose_refs(), 0))
1059                 return 1;
1060
1061         lock = lock_ref_sha1_basic(renamed_ref, NULL, 0, NULL);
1062         if (!lock)
1063                 return error("unable to lock %s", renamed_ref);
1064         lock->force_write = 1;
1065         if (write_ref_sha1(lock, orig_sha1, logmsg))
1066                 return error("unable to save current sha1 in %s", renamed_ref);
1067
1068         if (log && rename(git_path("logs/%s", oldref), git_path("tmp-renamed-log")))
1069                 return error("unable to move logfile logs/%s to tmp-renamed-log: %s",
1070                         oldref, strerror(errno));
1071
1072         if (delete_ref(oldref, orig_sha1, REF_NODEREF)) {
1073                 error("unable to delete old %s", oldref);
1074                 goto rollback;
1075         }
1076
1077         if (resolve_ref(newref, sha1, 1, &flag) && delete_ref(newref, sha1, REF_NODEREF)) {
1078                 if (errno==EISDIR) {
1079                         if (remove_empty_directories(git_path("%s", newref))) {
1080                                 error("Directory not empty: %s", newref);
1081                                 goto rollback;
1082                         }
1083                 } else {
1084                         error("unable to delete existing %s", newref);
1085                         goto rollback;
1086                 }
1087         }
1088
1089         if (log && safe_create_leading_directories(git_path("logs/%s", newref))) {
1090                 error("unable to create directory for %s", newref);
1091                 goto rollback;
1092         }
1093
1094  retry:
1095         if (log && rename(git_path("tmp-renamed-log"), git_path("logs/%s", newref))) {
1096                 if (errno==EISDIR || errno==ENOTDIR) {
1097                         /*
1098                          * rename(a, b) when b is an existing
1099                          * directory ought to result in ISDIR, but
1100                          * Solaris 5.8 gives ENOTDIR.  Sheesh.
1101                          */
1102                         if (remove_empty_directories(git_path("logs/%s", newref))) {
1103                                 error("Directory not empty: logs/%s", newref);
1104                                 goto rollback;
1105                         }
1106                         goto retry;
1107                 } else {
1108                         error("unable to move logfile tmp-renamed-log to logs/%s: %s",
1109                                 newref, strerror(errno));
1110                         goto rollback;
1111                 }
1112         }
1113         logmoved = log;
1114
1115         lock = lock_ref_sha1_basic(newref, NULL, 0, NULL);
1116         if (!lock) {
1117                 error("unable to lock %s for update", newref);
1118                 goto rollback;
1119         }
1120         lock->force_write = 1;
1121         hashcpy(lock->old_sha1, orig_sha1);
1122         if (write_ref_sha1(lock, orig_sha1, logmsg)) {
1123                 error("unable to write current sha1 into %s", newref);
1124                 goto rollback;
1125         }
1126
1127         return 0;
1128
1129  rollback:
1130         lock = lock_ref_sha1_basic(oldref, NULL, 0, NULL);
1131         if (!lock) {
1132                 error("unable to lock %s for rollback", oldref);
1133                 goto rollbacklog;
1134         }
1135
1136         lock->force_write = 1;
1137         flag = log_all_ref_updates;
1138         log_all_ref_updates = 0;
1139         if (write_ref_sha1(lock, orig_sha1, NULL))
1140                 error("unable to write current sha1 into %s", oldref);
1141         log_all_ref_updates = flag;
1142
1143  rollbacklog:
1144         if (logmoved && rename(git_path("logs/%s", newref), git_path("logs/%s", oldref)))
1145                 error("unable to restore logfile %s from %s: %s",
1146                         oldref, newref, strerror(errno));
1147         if (!logmoved && log &&
1148             rename(git_path("tmp-renamed-log"), git_path("logs/%s", oldref)))
1149                 error("unable to restore logfile %s from tmp-renamed-log: %s",
1150                         oldref, strerror(errno));
1151
1152         return 1;
1153 }
1154
1155 int close_ref(struct ref_lock *lock)
1156 {
1157         if (close_lock_file(lock->lk))
1158                 return -1;
1159         lock->lock_fd = -1;
1160         return 0;
1161 }
1162
1163 int commit_ref(struct ref_lock *lock)
1164 {
1165         if (commit_lock_file(lock->lk))
1166                 return -1;
1167         lock->lock_fd = -1;
1168         return 0;
1169 }
1170
1171 void unlock_ref(struct ref_lock *lock)
1172 {
1173         /* Do not free lock->lk -- atexit() still looks at them */
1174         if (lock->lk)
1175                 rollback_lock_file(lock->lk);
1176         free(lock->ref_name);
1177         free(lock->orig_ref_name);
1178         free(lock);
1179 }
1180
1181 /*
1182  * copy the reflog message msg to buf, which has been allocated sufficiently
1183  * large, while cleaning up the whitespaces.  Especially, convert LF to space,
1184  * because reflog file is one line per entry.
1185  */
1186 static int copy_msg(char *buf, const char *msg)
1187 {
1188         char *cp = buf;
1189         char c;
1190         int wasspace = 1;
1191
1192         *cp++ = '\t';
1193         while ((c = *msg++)) {
1194                 if (wasspace && isspace(c))
1195                         continue;
1196                 wasspace = isspace(c);
1197                 if (wasspace)
1198                         c = ' ';
1199                 *cp++ = c;
1200         }
1201         while (buf < cp && isspace(cp[-1]))
1202                 cp--;
1203         *cp++ = '\n';
1204         return cp - buf;
1205 }
1206
1207 static int log_ref_write(const char *ref_name, const unsigned char *old_sha1,
1208                          const unsigned char *new_sha1, const char *msg)
1209 {
1210         int logfd, written, oflags = O_APPEND | O_WRONLY;
1211         unsigned maxlen, len;
1212         int msglen;
1213         char log_file[PATH_MAX];
1214         char *logrec;
1215         const char *committer;
1216
1217         if (log_all_ref_updates < 0)
1218                 log_all_ref_updates = !is_bare_repository();
1219
1220         git_snpath(log_file, sizeof(log_file), "logs/%s", ref_name);
1221
1222         if (log_all_ref_updates &&
1223             (!prefixcmp(ref_name, "refs/heads/") ||
1224              !prefixcmp(ref_name, "refs/remotes/") ||
1225              !strcmp(ref_name, "HEAD"))) {
1226                 if (safe_create_leading_directories(log_file) < 0)
1227                         return error("unable to create directory for %s",
1228                                      log_file);
1229                 oflags |= O_CREAT;
1230         }
1231
1232         logfd = open(log_file, oflags, 0666);
1233         if (logfd < 0) {
1234                 if (!(oflags & O_CREAT) && errno == ENOENT)
1235                         return 0;
1236
1237                 if ((oflags & O_CREAT) && errno == EISDIR) {
1238                         if (remove_empty_directories(log_file)) {
1239                                 return error("There are still logs under '%s'",
1240                                              log_file);
1241                         }
1242                         logfd = open(log_file, oflags, 0666);
1243                 }
1244
1245                 if (logfd < 0)
1246                         return error("Unable to append to %s: %s",
1247                                      log_file, strerror(errno));
1248         }
1249
1250         adjust_shared_perm(log_file);
1251
1252         msglen = msg ? strlen(msg) : 0;
1253         committer = git_committer_info(0);
1254         maxlen = strlen(committer) + msglen + 100;
1255         logrec = xmalloc(maxlen);
1256         len = sprintf(logrec, "%s %s %s\n",
1257                       sha1_to_hex(old_sha1),
1258                       sha1_to_hex(new_sha1),
1259                       committer);
1260         if (msglen)
1261                 len += copy_msg(logrec + len - 1, msg) - 1;
1262         written = len <= maxlen ? write_in_full(logfd, logrec, len) : -1;
1263         free(logrec);
1264         if (close(logfd) != 0 || written != len)
1265                 return error("Unable to append to %s", log_file);
1266         return 0;
1267 }
1268
1269 static int is_branch(const char *refname)
1270 {
1271         return !strcmp(refname, "HEAD") || !prefixcmp(refname, "refs/heads/");
1272 }
1273
1274 int write_ref_sha1(struct ref_lock *lock,
1275         const unsigned char *sha1, const char *logmsg)
1276 {
1277         static char term = '\n';
1278         struct object *o;
1279
1280         if (!lock)
1281                 return -1;
1282         if (!lock->force_write && !hashcmp(lock->old_sha1, sha1)) {
1283                 unlock_ref(lock);
1284                 return 0;
1285         }
1286         o = parse_object(sha1);
1287         if (!o) {
1288                 error("Trying to write ref %s with nonexistant object %s",
1289                         lock->ref_name, sha1_to_hex(sha1));
1290                 unlock_ref(lock);
1291                 return -1;
1292         }
1293         if (o->type != OBJ_COMMIT && is_branch(lock->ref_name)) {
1294                 error("Trying to write non-commit object %s to branch %s",
1295                         sha1_to_hex(sha1), lock->ref_name);
1296                 unlock_ref(lock);
1297                 return -1;
1298         }
1299         if (write_in_full(lock->lock_fd, sha1_to_hex(sha1), 40) != 40 ||
1300             write_in_full(lock->lock_fd, &term, 1) != 1
1301                 || close_ref(lock) < 0) {
1302                 error("Couldn't write %s", lock->lk->filename);
1303                 unlock_ref(lock);
1304                 return -1;
1305         }
1306         invalidate_cached_refs();
1307         if (log_ref_write(lock->ref_name, lock->old_sha1, sha1, logmsg) < 0 ||
1308             (strcmp(lock->ref_name, lock->orig_ref_name) &&
1309              log_ref_write(lock->orig_ref_name, lock->old_sha1, sha1, logmsg) < 0)) {
1310                 unlock_ref(lock);
1311                 return -1;
1312         }
1313         if (strcmp(lock->orig_ref_name, "HEAD") != 0) {
1314                 /*
1315                  * Special hack: If a branch is updated directly and HEAD
1316                  * points to it (may happen on the remote side of a push
1317                  * for example) then logically the HEAD reflog should be
1318                  * updated too.
1319                  * A generic solution implies reverse symref information,
1320                  * but finding all symrefs pointing to the given branch
1321                  * would be rather costly for this rare event (the direct
1322                  * update of a branch) to be worth it.  So let's cheat and
1323                  * check with HEAD only which should cover 99% of all usage
1324                  * scenarios (even 100% of the default ones).
1325                  */
1326                 unsigned char head_sha1[20];
1327                 int head_flag;
1328                 const char *head_ref;
1329                 head_ref = resolve_ref("HEAD", head_sha1, 1, &head_flag);
1330                 if (head_ref && (head_flag & REF_ISSYMREF) &&
1331                     !strcmp(head_ref, lock->ref_name))
1332                         log_ref_write("HEAD", lock->old_sha1, sha1, logmsg);
1333         }
1334         if (commit_ref(lock)) {
1335                 error("Couldn't set %s", lock->ref_name);
1336                 unlock_ref(lock);
1337                 return -1;
1338         }
1339         unlock_ref(lock);
1340         return 0;
1341 }
1342
1343 int create_symref(const char *ref_target, const char *refs_heads_master,
1344                   const char *logmsg)
1345 {
1346         const char *lockpath;
1347         char ref[1000];
1348         int fd, len, written;
1349         char *git_HEAD = git_pathdup("%s", ref_target);
1350         unsigned char old_sha1[20], new_sha1[20];
1351
1352         if (logmsg && read_ref(ref_target, old_sha1))
1353                 hashclr(old_sha1);
1354
1355         if (safe_create_leading_directories(git_HEAD) < 0)
1356                 return error("unable to create directory for %s", git_HEAD);
1357
1358 #ifndef NO_SYMLINK_HEAD
1359         if (prefer_symlink_refs) {
1360                 unlink(git_HEAD);
1361                 if (!symlink(refs_heads_master, git_HEAD))
1362                         goto done;
1363                 fprintf(stderr, "no symlink - falling back to symbolic ref\n");
1364         }
1365 #endif
1366
1367         len = snprintf(ref, sizeof(ref), "ref: %s\n", refs_heads_master);
1368         if (sizeof(ref) <= len) {
1369                 error("refname too long: %s", refs_heads_master);
1370                 goto error_free_return;
1371         }
1372         lockpath = mkpath("%s.lock", git_HEAD);
1373         fd = open(lockpath, O_CREAT | O_EXCL | O_WRONLY, 0666);
1374         if (fd < 0) {
1375                 error("Unable to open %s for writing", lockpath);
1376                 goto error_free_return;
1377         }
1378         written = write_in_full(fd, ref, len);
1379         if (close(fd) != 0 || written != len) {
1380                 error("Unable to write to %s", lockpath);
1381                 goto error_unlink_return;
1382         }
1383         if (rename(lockpath, git_HEAD) < 0) {
1384                 error("Unable to create %s", git_HEAD);
1385                 goto error_unlink_return;
1386         }
1387         if (adjust_shared_perm(git_HEAD)) {
1388                 error("Unable to fix permissions on %s", lockpath);
1389         error_unlink_return:
1390                 unlink_or_warn(lockpath);
1391         error_free_return:
1392                 free(git_HEAD);
1393                 return -1;
1394         }
1395
1396 #ifndef NO_SYMLINK_HEAD
1397         done:
1398 #endif
1399         if (logmsg && !read_ref(refs_heads_master, new_sha1))
1400                 log_ref_write(ref_target, old_sha1, new_sha1, logmsg);
1401
1402         free(git_HEAD);
1403         return 0;
1404 }
1405
1406 static char *ref_msg(const char *line, const char *endp)
1407 {
1408         const char *ep;
1409         line += 82;
1410         ep = memchr(line, '\n', endp - line);
1411         if (!ep)
1412                 ep = endp;
1413         return xmemdupz(line, ep - line);
1414 }
1415
1416 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)
1417 {
1418         const char *logfile, *logdata, *logend, *rec, *lastgt, *lastrec;
1419         char *tz_c;
1420         int logfd, tz, reccnt = 0;
1421         struct stat st;
1422         unsigned long date;
1423         unsigned char logged_sha1[20];
1424         void *log_mapped;
1425         size_t mapsz;
1426
1427         logfile = git_path("logs/%s", ref);
1428         logfd = open(logfile, O_RDONLY, 0);
1429         if (logfd < 0)
1430                 die_errno("Unable to read log '%s'", logfile);
1431         fstat(logfd, &st);
1432         if (!st.st_size)
1433                 die("Log %s is empty.", logfile);
1434         mapsz = xsize_t(st.st_size);
1435         log_mapped = xmmap(NULL, mapsz, PROT_READ, MAP_PRIVATE, logfd, 0);
1436         logdata = log_mapped;
1437         close(logfd);
1438
1439         lastrec = NULL;
1440         rec = logend = logdata + st.st_size;
1441         while (logdata < rec) {
1442                 reccnt++;
1443                 if (logdata < rec && *(rec-1) == '\n')
1444                         rec--;
1445                 lastgt = NULL;
1446                 while (logdata < rec && *(rec-1) != '\n') {
1447                         rec--;
1448                         if (*rec == '>')
1449                                 lastgt = rec;
1450                 }
1451                 if (!lastgt)
1452                         die("Log %s is corrupt.", logfile);
1453                 date = strtoul(lastgt + 1, &tz_c, 10);
1454                 if (date <= at_time || cnt == 0) {
1455                         tz = strtoul(tz_c, NULL, 10);
1456                         if (msg)
1457                                 *msg = ref_msg(rec, logend);
1458                         if (cutoff_time)
1459                                 *cutoff_time = date;
1460                         if (cutoff_tz)
1461                                 *cutoff_tz = tz;
1462                         if (cutoff_cnt)
1463                                 *cutoff_cnt = reccnt - 1;
1464                         if (lastrec) {
1465                                 if (get_sha1_hex(lastrec, logged_sha1))
1466                                         die("Log %s is corrupt.", logfile);
1467                                 if (get_sha1_hex(rec + 41, sha1))
1468                                         die("Log %s is corrupt.", logfile);
1469                                 if (hashcmp(logged_sha1, sha1)) {
1470                                         warning("Log %s has gap after %s.",
1471                                                 logfile, show_date(date, tz, DATE_RFC2822));
1472                                 }
1473                         }
1474                         else if (date == at_time) {
1475                                 if (get_sha1_hex(rec + 41, sha1))
1476                                         die("Log %s is corrupt.", logfile);
1477                         }
1478                         else {
1479                                 if (get_sha1_hex(rec + 41, logged_sha1))
1480                                         die("Log %s is corrupt.", logfile);
1481                                 if (hashcmp(logged_sha1, sha1)) {
1482                                         warning("Log %s unexpectedly ended on %s.",
1483                                                 logfile, show_date(date, tz, DATE_RFC2822));
1484                                 }
1485                         }
1486                         munmap(log_mapped, mapsz);
1487                         return 0;
1488                 }
1489                 lastrec = rec;
1490                 if (cnt > 0)
1491                         cnt--;
1492         }
1493
1494         rec = logdata;
1495         while (rec < logend && *rec != '>' && *rec != '\n')
1496                 rec++;
1497         if (rec == logend || *rec == '\n')
1498                 die("Log %s is corrupt.", logfile);
1499         date = strtoul(rec + 1, &tz_c, 10);
1500         tz = strtoul(tz_c, NULL, 10);
1501         if (get_sha1_hex(logdata, sha1))
1502                 die("Log %s is corrupt.", logfile);
1503         if (is_null_sha1(sha1)) {
1504                 if (get_sha1_hex(logdata + 41, sha1))
1505                         die("Log %s is corrupt.", logfile);
1506         }
1507         if (msg)
1508                 *msg = ref_msg(logdata, logend);
1509         munmap(log_mapped, mapsz);
1510
1511         if (cutoff_time)
1512                 *cutoff_time = date;
1513         if (cutoff_tz)
1514                 *cutoff_tz = tz;
1515         if (cutoff_cnt)
1516                 *cutoff_cnt = reccnt;
1517         return 1;
1518 }
1519
1520 int for_each_recent_reflog_ent(const char *ref, each_reflog_ent_fn fn, long ofs, void *cb_data)
1521 {
1522         const char *logfile;
1523         FILE *logfp;
1524         char buf[1024];
1525         int ret = 0;
1526
1527         logfile = git_path("logs/%s", ref);
1528         logfp = fopen(logfile, "r");
1529         if (!logfp)
1530                 return -1;
1531
1532         if (ofs) {
1533                 struct stat statbuf;
1534                 if (fstat(fileno(logfp), &statbuf) ||
1535                     statbuf.st_size < ofs ||
1536                     fseek(logfp, -ofs, SEEK_END) ||
1537                     fgets(buf, sizeof(buf), logfp)) {
1538                         fclose(logfp);
1539                         return -1;
1540                 }
1541         }
1542
1543         while (fgets(buf, sizeof(buf), logfp)) {
1544                 unsigned char osha1[20], nsha1[20];
1545                 char *email_end, *message;
1546                 unsigned long timestamp;
1547                 int len, tz;
1548
1549                 /* old SP new SP name <email> SP time TAB msg LF */
1550                 len = strlen(buf);
1551                 if (len < 83 || buf[len-1] != '\n' ||
1552                     get_sha1_hex(buf, osha1) || buf[40] != ' ' ||
1553                     get_sha1_hex(buf + 41, nsha1) || buf[81] != ' ' ||
1554                     !(email_end = strchr(buf + 82, '>')) ||
1555                     email_end[1] != ' ' ||
1556                     !(timestamp = strtoul(email_end + 2, &message, 10)) ||
1557                     !message || message[0] != ' ' ||
1558                     (message[1] != '+' && message[1] != '-') ||
1559                     !isdigit(message[2]) || !isdigit(message[3]) ||
1560                     !isdigit(message[4]) || !isdigit(message[5]))
1561                         continue; /* corrupt? */
1562                 email_end[1] = '\0';
1563                 tz = strtol(message + 1, NULL, 10);
1564                 if (message[6] != '\t')
1565                         message += 6;
1566                 else
1567                         message += 7;
1568                 ret = fn(osha1, nsha1, buf+82, timestamp, tz, message, cb_data);
1569                 if (ret)
1570                         break;
1571         }
1572         fclose(logfp);
1573         return ret;
1574 }
1575
1576 int for_each_reflog_ent(const char *ref, each_reflog_ent_fn fn, void *cb_data)
1577 {
1578         return for_each_recent_reflog_ent(ref, fn, 0, cb_data);
1579 }
1580
1581 static int do_for_each_reflog(const char *base, each_ref_fn fn, void *cb_data)
1582 {
1583         DIR *dir = opendir(git_path("logs/%s", base));
1584         int retval = 0;
1585
1586         if (dir) {
1587                 struct dirent *de;
1588                 int baselen = strlen(base);
1589                 char *log = xmalloc(baselen + 257);
1590
1591                 memcpy(log, base, baselen);
1592                 if (baselen && base[baselen-1] != '/')
1593                         log[baselen++] = '/';
1594
1595                 while ((de = readdir(dir)) != NULL) {
1596                         struct stat st;
1597                         int namelen;
1598
1599                         if (de->d_name[0] == '.')
1600                                 continue;
1601                         namelen = strlen(de->d_name);
1602                         if (namelen > 255)
1603                                 continue;
1604                         if (has_extension(de->d_name, ".lock"))
1605                                 continue;
1606                         memcpy(log + baselen, de->d_name, namelen+1);
1607                         if (stat(git_path("logs/%s", log), &st) < 0)
1608                                 continue;
1609                         if (S_ISDIR(st.st_mode)) {
1610                                 retval = do_for_each_reflog(log, fn, cb_data);
1611                         } else {
1612                                 unsigned char sha1[20];
1613                                 if (!resolve_ref(log, sha1, 0, NULL))
1614                                         retval = error("bad ref for %s", log);
1615                                 else
1616                                         retval = fn(log, sha1, 0, cb_data);
1617                         }
1618                         if (retval)
1619                                 break;
1620                 }
1621                 free(log);
1622                 closedir(dir);
1623         }
1624         else if (*base)
1625                 return errno;
1626         return retval;
1627 }
1628
1629 int for_each_reflog(each_ref_fn fn, void *cb_data)
1630 {
1631         return do_for_each_reflog("", fn, cb_data);
1632 }
1633
1634 int update_ref(const char *action, const char *refname,
1635                 const unsigned char *sha1, const unsigned char *oldval,
1636                 int flags, enum action_on_err onerr)
1637 {
1638         static struct ref_lock *lock;
1639         lock = lock_any_ref_for_update(refname, oldval, flags);
1640         if (!lock) {
1641                 const char *str = "Cannot lock the ref '%s'.";
1642                 switch (onerr) {
1643                 case MSG_ON_ERR: error(str, refname); break;
1644                 case DIE_ON_ERR: die(str, refname); break;
1645                 case QUIET_ON_ERR: break;
1646                 }
1647                 return 1;
1648         }
1649         if (write_ref_sha1(lock, sha1, action) < 0) {
1650                 const char *str = "Cannot update the ref '%s'.";
1651                 switch (onerr) {
1652                 case MSG_ON_ERR: error(str, refname); break;
1653                 case DIE_ON_ERR: die(str, refname); break;
1654                 case QUIET_ON_ERR: break;
1655                 }
1656                 return 1;
1657         }
1658         return 0;
1659 }
1660
1661 struct ref *find_ref_by_name(const struct ref *list, const char *name)
1662 {
1663         for ( ; list; list = list->next)
1664                 if (!strcmp(list->name, name))
1665                         return (struct ref *)list;
1666         return NULL;
1667 }
1668
1669 /*
1670  * generate a format suitable for scanf from a ref_rev_parse_rules
1671  * rule, that is replace the "%.*s" spec with a "%s" spec
1672  */
1673 static void gen_scanf_fmt(char *scanf_fmt, const char *rule)
1674 {
1675         char *spec;
1676
1677         spec = strstr(rule, "%.*s");
1678         if (!spec || strstr(spec + 4, "%.*s"))
1679                 die("invalid rule in ref_rev_parse_rules: %s", rule);
1680
1681         /* copy all until spec */
1682         strncpy(scanf_fmt, rule, spec - rule);
1683         scanf_fmt[spec - rule] = '\0';
1684         /* copy new spec */
1685         strcat(scanf_fmt, "%s");
1686         /* copy remaining rule */
1687         strcat(scanf_fmt, spec + 4);
1688
1689         return;
1690 }
1691
1692 char *shorten_unambiguous_ref(const char *ref, int strict)
1693 {
1694         int i;
1695         static char **scanf_fmts;
1696         static int nr_rules;
1697         char *short_name;
1698
1699         /* pre generate scanf formats from ref_rev_parse_rules[] */
1700         if (!nr_rules) {
1701                 size_t total_len = 0;
1702
1703                 /* the rule list is NULL terminated, count them first */
1704                 for (; ref_rev_parse_rules[nr_rules]; nr_rules++)
1705                         /* no +1 because strlen("%s") < strlen("%.*s") */
1706                         total_len += strlen(ref_rev_parse_rules[nr_rules]);
1707
1708                 scanf_fmts = xmalloc(nr_rules * sizeof(char *) + total_len);
1709
1710                 total_len = 0;
1711                 for (i = 0; i < nr_rules; i++) {
1712                         scanf_fmts[i] = (char *)&scanf_fmts[nr_rules]
1713                                         + total_len;
1714                         gen_scanf_fmt(scanf_fmts[i], ref_rev_parse_rules[i]);
1715                         total_len += strlen(ref_rev_parse_rules[i]);
1716                 }
1717         }
1718
1719         /* bail out if there are no rules */
1720         if (!nr_rules)
1721                 return xstrdup(ref);
1722
1723         /* buffer for scanf result, at most ref must fit */
1724         short_name = xstrdup(ref);
1725
1726         /* skip first rule, it will always match */
1727         for (i = nr_rules - 1; i > 0 ; --i) {
1728                 int j;
1729                 int rules_to_fail = i;
1730                 int short_name_len;
1731
1732                 if (1 != sscanf(ref, scanf_fmts[i], short_name))
1733                         continue;
1734
1735                 short_name_len = strlen(short_name);
1736
1737                 /*
1738                  * in strict mode, all (except the matched one) rules
1739                  * must fail to resolve to a valid non-ambiguous ref
1740                  */
1741                 if (strict)
1742                         rules_to_fail = nr_rules;
1743
1744                 /*
1745                  * check if the short name resolves to a valid ref,
1746                  * but use only rules prior to the matched one
1747                  */
1748                 for (j = 0; j < rules_to_fail; j++) {
1749                         const char *rule = ref_rev_parse_rules[j];
1750                         unsigned char short_objectname[20];
1751                         char refname[PATH_MAX];
1752
1753                         /* skip matched rule */
1754                         if (i == j)
1755                                 continue;
1756
1757                         /*
1758                          * the short name is ambiguous, if it resolves
1759                          * (with this previous rule) to a valid ref
1760                          * read_ref() returns 0 on success
1761                          */
1762                         mksnpath(refname, sizeof(refname),
1763                                  rule, short_name_len, short_name);
1764                         if (!read_ref(refname, short_objectname))
1765                                 break;
1766                 }
1767
1768                 /*
1769                  * short name is non-ambiguous if all previous rules
1770                  * haven't resolved to a valid ref
1771                  */
1772                 if (j == rules_to_fail)
1773                         return short_name;
1774         }
1775
1776         free(short_name);
1777         return xstrdup(ref);
1778 }