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 #define REF_BROKEN 010
  10
  11 struct ref_list {
  12         struct ref_list *next;
  13         unsigned char flag; /* ISSYMREF? ISPACKED? */
  14         unsigned char sha1[20];
  15         unsigned char peeled[20];
  16         char name[FLEX_ARRAY];
  17 };
  18
  19 static const char *parse_ref_line(char *line, unsigned char *sha1)
  20 {
  21         /*
  22          * 42: the answer to everything.
  23          *
  24          * In this case, it happens to be the answer to
  25          *  40 (length of sha1 hex representation)
  26          *  +1 (space in between hex and name)
  27          *  +1 (newline at the end of the line)
  28          */
  29         int len = strlen(line) - 42;
  30
  31         if (len <= 0)
  32                 return NULL;
  33         if (get_sha1_hex(line, sha1) < 0)
  34                 return NULL;
  35         if (!isspace(line[40]))
  36                 return NULL;
  37         line += 41;
  38         if (isspace(*line))
  39                 return NULL;
  40         if (line[len] != '\n')
  41                 return NULL;
  42         line[len] = 0;
  43
  44         return line;
  45 }
  46
  47 static struct ref_list *add_ref(const char *name, const unsigned char *sha1,
  48                                 int flag, struct ref_list *list,
  49                                 struct ref_list **new_entry)
  50 {
  51         int len;
  52         struct ref_list *entry;
  53
  54         /* Allocate it and add it in.. */
  55         len = strlen(name) + 1;
  56         entry = xmalloc(sizeof(struct ref_list) + len);
  57         hashcpy(entry->sha1, sha1);
  58         hashclr(entry->peeled);
  59         memcpy(entry->name, name, len);
  60         entry->flag = flag;
  61         entry->next = list;
  62         if (new_entry)
  63                 *new_entry = entry;
  64         return entry;
  65 }
  66
  67 /* merge sort the ref list */
  68 static struct ref_list *sort_ref_list(struct ref_list *list)
  69 {
  70         int psize, qsize, last_merge_count, cmp;
  71         struct ref_list *p, *q, *l, *e;
  72         struct ref_list *new_list = list;
  73         int k = 1;
  74         int merge_count = 0;
  75
  76         if (!list)
  77                 return list;
  78
  79         do {
  80                 last_merge_count = merge_count;
  81                 merge_count = 0;
  82
  83                 psize = 0;
  84
  85                 p = new_list;
  86                 q = new_list;
  87                 new_list = NULL;
  88                 l = NULL;
  89
  90                 while (p) {
  91                         merge_count++;
  92
  93                         while (psize < k && q->next) {
  94                                 q = q->next;
  95                                 psize++;
  96                         }
  97                         qsize = k;
  98
  99                         while ((psize > 0) || (qsize > 0 && q)) {
 100                                 if (qsize == 0 || !q) {
 101                                         e = p;
 102                                         p = p->next;
 103                                         psize--;
 104                                 } else if (psize == 0) {
 105                                         e = q;
 106                                         q = q->next;
 107                                         qsize--;
 108                                 } else {
 109                                         cmp = strcmp(q->name, p->name);
 110                                         if (cmp < 0) {
 111                                                 e = q;
 112                                                 q = q->next;
 113                                                 qsize--;
 114                                         } else if (cmp > 0) {
 115                                                 e = p;
 116                                                 p = p->next;
 117                                                 psize--;
 118                                         } else {
 119                                                 if (hashcmp(q->sha1, p->sha1))
 120                                                         die("Duplicated ref, and SHA1s don't match: %s",
 121                                                             q->name);
 122                                                 warning("Duplicated ref: %s", q->name);
 123                                                 e = q;
 124                                                 q = q->next;
 125                                                 qsize--;
 126                                                 free(e);
 127                                                 e = p;
 128                                                 p = p->next;
 129                                                 psize--;
 130                                         }
 131                                 }
 132
 133                                 e->next = NULL;
 134
 135                                 if (l)
 136                                         l->next = e;
 137                                 if (!new_list)
 138                                         new_list = e;
 139                                 l = e;
 140                         }
 141
 142                         p = q;
 143                 };
 144
 145                 k = k * 2;
 146         } while ((last_merge_count != merge_count) || (last_merge_count != 1));
 147
 148         return new_list;
 149 }
 150
 151 /*
 152  * Future: need to be in "struct repository"
 153  * when doing a full libification.
 154  */
 155 static struct cached_refs {
 156         char did_loose;
 157         char did_packed;
 158         struct ref_list *loose;
 159         struct ref_list *packed;
 160 } cached_refs, submodule_refs;
 161 static struct ref_list *current_ref;
 162
 163 static struct ref_list *extra_refs;
 164
 165 static void free_ref_list(struct ref_list *list)
 166 {
 167         struct ref_list *next;
 168         for ( ; list; list = next) {
 169                 next = list->next;
 170                 free(list);
 171         }
 172 }
 173
 174 static void invalidate_cached_refs(void)
 175 {
 176         struct cached_refs *ca = &cached_refs;
 177
 178         if (ca->did_loose && ca->loose)
 179                 free_ref_list(ca->loose);
 180         if (ca->did_packed && ca->packed)
 181                 free_ref_list(ca->packed);
 182         ca->loose = ca->packed = NULL;
 183         ca->did_loose = ca->did_packed = 0;
 184 }
 185
 186 static void read_packed_refs(FILE *f, struct cached_refs *cached_refs)
 187 {
 188         struct ref_list *list = NULL;
 189         struct ref_list *last = NULL;
 190         char refline[PATH_MAX];
 191         int flag = REF_ISPACKED;
 192
 193         while (fgets(refline, sizeof(refline), f)) {
 194                 unsigned char sha1[20];
 195                 const char *name;
 196                 static const char header[] = "# pack-refs with:";
 197
 198                 if (!strncmp(refline, header, sizeof(header)-1)) {
 199                         const char *traits = refline + sizeof(header) - 1;
 200                         if (strstr(traits, " peeled "))
 201                                 flag |= REF_KNOWS_PEELED;
 202                         /* perhaps other traits later as well */
 203                         continue;
 204                 }
 205
 206                 name = parse_ref_line(refline, sha1);
 207                 if (name) {
 208                         list = add_ref(name, sha1, flag, list, &last);
 209                         continue;
 210                 }
 211                 if (last &&
 212                     refline[0] == '^' &&
 213                     strlen(refline) == 42 &&
 214                     refline[41] == '\n' &&
 215                     !get_sha1_hex(refline + 1, sha1))
 216                         hashcpy(last->peeled, sha1);
 217         }
 218         cached_refs->packed = sort_ref_list(list);
 219 }
 220
 221 void add_extra_ref(const char *name, const unsigned char *sha1, int flag)
 222 {
 223         extra_refs = add_ref(name, sha1, flag, extra_refs, NULL);
 224 }
 225
 226 void clear_extra_refs(void)
 227 {
 228         free_ref_list(extra_refs);
 229         extra_refs = NULL;
 230 }
 231
 232 static struct ref_list *get_packed_refs(const char *submodule)
 233 {
 234         const char *packed_refs_file;
 235         struct cached_refs *refs;
 236
 237         if (submodule) {
 238                 packed_refs_file = git_path_submodule(submodule, "packed-refs");
 239                 refs = &submodule_refs;
 240                 free_ref_list(refs->packed);
 241         } else {
 242                 packed_refs_file = git_path("packed-refs");
 243                 refs = &cached_refs;
 244         }
 245
 246         if (!refs->did_packed || submodule) {
 247                 FILE *f = fopen(packed_refs_file, "r");
 248                 refs->packed = NULL;
 249                 if (f) {
 250                         read_packed_refs(f, refs);
 251                         fclose(f);
 252                 }
 253                 refs->did_packed = 1;
 254         }
 255         return refs->packed;
 256 }
 257
 258 static struct ref_list *get_ref_dir(const char *submodule, const char *base,
 259                                     struct ref_list *list)
 260 {
 261         DIR *dir;
 262         const char *path;
 263
 264         if (submodule)
 265                 path = git_path_submodule(submodule, "%s", base);
 266         else
 267                 path = git_path("%s", base);
 268
 269
 270         dir = opendir(path);
 271
 272         if (dir) {
 273                 struct dirent *de;
 274                 int baselen = strlen(base);
 275                 char *ref = xmalloc(baselen + 257);
 276
 277                 memcpy(ref, base, baselen);
 278                 if (baselen && base[baselen-1] != '/')
 279                         ref[baselen++] = '/';
 280
 281                 while ((de = readdir(dir)) != NULL) {
 282                         unsigned char sha1[20];
 283                         struct stat st;
 284                         int flag;
 285                         int namelen;
 286                         const char *refdir;
 287
 288                         if (de->d_name[0] == '.')
 289                                 continue;
 290                         namelen = strlen(de->d_name);
 291                         if (namelen > 255)
 292                                 continue;
 293                         if (has_extension(de->d_name, ".lock"))
 294                                 continue;
 295                         memcpy(ref + baselen, de->d_name, namelen+1);
 296                         refdir = submodule
 297                                 ? git_path_submodule(submodule, "%s", ref)
 298                                 : git_path("%s", ref);
 299                         if (stat(refdir, &st) < 0)
 300                                 continue;
 301                         if (S_ISDIR(st.st_mode)) {
 302                                 list = get_ref_dir(submodule, ref, list);
 303                                 continue;
 304                         }
 305                         if (submodule) {
 306                                 hashclr(sha1);
 307                                 flag = 0;
 308                                 if (resolve_gitlink_ref(submodule, ref, sha1) < 0) {
 309                                         hashclr(sha1);
 310                                         flag |= REF_BROKEN;
 311                                 }
 312                         } else
 313                                 if (!resolve_ref(ref, sha1, 1, &flag)) {
 314                                         hashclr(sha1);
 315                                         flag |= REF_BROKEN;
 316                                 }
 317                         list = add_ref(ref, sha1, flag, list, NULL);
 318                 }
 319                 free(ref);
 320                 closedir(dir);
 321         }
 322         return sort_ref_list(list);
 323 }
 324
 325 struct warn_if_dangling_data {
 326         FILE *fp;
 327         const char *refname;
 328         const char *msg_fmt;
 329 };
 330
 331 static int warn_if_dangling_symref(const char *refname, const unsigned char *sha1,
 332                                    int flags, void *cb_data)
 333 {
 334         struct warn_if_dangling_data *d = cb_data;
 335         const char *resolves_to;
 336         unsigned char junk[20];
 337
 338         if (!(flags & REF_ISSYMREF))
 339                 return 0;
 340
 341         resolves_to = resolve_ref(refname, junk, 0, NULL);
 342         if (!resolves_to || strcmp(resolves_to, d->refname))
 343                 return 0;
 344
 345         fprintf(d->fp, d->msg_fmt, refname);
 346         return 0;
 347 }
 348
 349 void warn_dangling_symref(FILE *fp, const char *msg_fmt, const char *refname)
 350 {
 351         struct warn_if_dangling_data data;
 352
 353         data.fp = fp;
 354         data.refname = refname;
 355         data.msg_fmt = msg_fmt;
 356         for_each_rawref(warn_if_dangling_symref, &data);
 357 }
 358
 359 static struct ref_list *get_loose_refs(const char *submodule)
 360 {
 361         if (submodule) {
 362                 free_ref_list(submodule_refs.loose);
 363                 submodule_refs.loose = get_ref_dir(submodule, "refs", NULL);
 364                 return submodule_refs.loose;
 365         }
 366
 367         if (!cached_refs.did_loose) {
 368                 cached_refs.loose = get_ref_dir(NULL, "refs", NULL);
 369                 cached_refs.did_loose = 1;
 370         }
 371         return cached_refs.loose;
 372 }
 373
 374 /* We allow "recursive" symbolic refs. Only within reason, though */
 375 #define MAXDEPTH 5
 376 #define MAXREFLEN (1024)
 377
 378 static int resolve_gitlink_packed_ref(char *name, int pathlen, const char *refname, unsigned char *result)
 379 {
 380         FILE *f;
 381         struct cached_refs refs;
 382         struct ref_list *ref;
 383         int retval;
 384
 385         strcpy(name + pathlen, "packed-refs");
 386         f = fopen(name, "r");
 387         if (!f)
 388                 return -1;
 389         read_packed_refs(f, &refs);
 390         fclose(f);
 391         ref = refs.packed;
 392         retval = -1;
 393         while (ref) {
 394                 if (!strcmp(ref->name, refname)) {
 395                         retval = 0;
 396                         memcpy(result, ref->sha1, 20);
 397                         break;
 398                 }
 399                 ref = ref->next;
 400         }
 401         free_ref_list(refs.packed);
 402         return retval;
 403 }
 404
 405 static int resolve_gitlink_ref_recursive(char *name, int pathlen, const char *refname, unsigned char *result, int recursion)
 406 {
 407         int fd, len = strlen(refname);
 408         char buffer[128], *p;
 409
 410         if (recursion > MAXDEPTH || len > MAXREFLEN)
 411                 return -1;
 412         memcpy(name + pathlen, refname, len+1);
 413         fd = open(name, O_RDONLY);
 414         if (fd < 0)
 415                 return resolve_gitlink_packed_ref(name, pathlen, refname, result);
 416
 417         len = read(fd, buffer, sizeof(buffer)-1);
 418         close(fd);
 419         if (len < 0)
 420                 return -1;
 421         while (len && isspace(buffer[len-1]))
 422                 len--;
 423         buffer[len] = 0;
 424
 425         /* Was it a detached head or an old-fashioned symlink? */
 426         if (!get_sha1_hex(buffer, result))
 427                 return 0;
 428
 429         /* Symref? */
 430         if (strncmp(buffer, "ref:", 4))
 431                 return -1;
 432         p = buffer + 4;
 433         while (isspace(*p))
 434                 p++;
 435
 436         return resolve_gitlink_ref_recursive(name, pathlen, p, result, recursion+1);
 437 }
 438
 439 int resolve_gitlink_ref(const char *path, const char *refname, unsigned char *result)
 440 {
 441         int len = strlen(path), retval;
 442         char *gitdir;
 443         const char *tmp;
 444
 445         while (len && path[len-1] == '/')
 446                 len--;
 447         if (!len)
 448                 return -1;
 449         gitdir = xmalloc(len + MAXREFLEN + 8);
 450         memcpy(gitdir, path, len);
 451         memcpy(gitdir + len, "/.git", 6);
 452         len += 5;
 453
 454         tmp = read_gitfile_gently(gitdir);
 455         if (tmp) {
 456                 free(gitdir);
 457                 len = strlen(tmp);
 458                 gitdir = xmalloc(len + MAXREFLEN + 3);
 459                 memcpy(gitdir, tmp, len);
 460         }
 461         gitdir[len] = '/';
 462         gitdir[++len] = '\0';
 463         retval = resolve_gitlink_ref_recursive(gitdir, len, refname, result, 0);
 464         free(gitdir);
 465         return retval;
 466 }
 467
 468 /*
 469  * If the "reading" argument is set, this function finds out what _object_
 470  * the ref points at by "reading" the ref.  The ref, if it is not symbolic,
 471  * has to exist, and if it is symbolic, it has to point at an existing ref,
 472  * because the "read" goes through the symref to the ref it points at.
 473  *
 474  * The access that is not "reading" may often be "writing", but does not
 475  * have to; it can be merely checking _where it leads to_. If it is a
 476  * prelude to "writing" to the ref, a write to a symref that points at
 477  * yet-to-be-born ref will create the real ref pointed by the symref.
 478  * reading=0 allows the caller to check where such a symref leads to.
 479  */
 480 const char *resolve_ref(const char *ref, unsigned char *sha1, int reading, int *flag)
 481 {
 482         int depth = MAXDEPTH;
 483         ssize_t len;
 484         char buffer[256];
 485         static char ref_buffer[256];
 486
 487         if (flag)
 488                 *flag = 0;
 489
 490         for (;;) {
 491                 char path[PATH_MAX];
 492                 struct stat st;
 493                 char *buf;
 494                 int fd;
 495
 496                 if (--depth < 0)
 497                         return NULL;
 498
 499                 git_snpath(path, sizeof(path), "%s", ref);
 500                 /* Special case: non-existing file. */
 501                 if (lstat(path, &st) < 0) {
 502                         struct ref_list *list = get_packed_refs(NULL);
 503                         while (list) {
 504                                 if (!strcmp(ref, list->name)) {
 505                                         hashcpy(sha1, list->sha1);
 506                                         if (flag)
 507                                                 *flag |= REF_ISPACKED;
 508                                         return ref;
 509                                 }
 510                                 list = list->next;
 511                         }
 512                         if (reading || errno != ENOENT)
 513                                 return NULL;
 514                         hashclr(sha1);
 515                         return ref;
 516                 }
 517
 518                 /* Follow "normalized" - ie "refs/.." symlinks by hand */
 519                 if (S_ISLNK(st.st_mode)) {
 520                         len = readlink(path, buffer, sizeof(buffer)-1);
 521                         if (len >= 5 && !memcmp("refs/", buffer, 5)) {
 522                                 buffer[len] = 0;
 523                                 strcpy(ref_buffer, buffer);
 524                                 ref = ref_buffer;
 525                                 if (flag)
 526                                         *flag |= REF_ISSYMREF;
 527                                 continue;
 528                         }
 529                 }
 530
 531                 /* Is it a directory? */
 532                 if (S_ISDIR(st.st_mode)) {
 533                         errno = EISDIR;
 534                         return NULL;
 535                 }
 536
 537                 /*
 538                  * Anything else, just open it and try to use it as
 539                  * a ref
 540                  */
 541                 fd = open(path, O_RDONLY);
 542                 if (fd < 0)
 543                         return NULL;
 544                 len = read_in_full(fd, buffer, sizeof(buffer)-1);
 545                 close(fd);
 546
 547                 /*
 548                  * Is it a symbolic ref?
 549                  */
 550                 if (len < 4 || memcmp("ref:", buffer, 4))
 551                         break;
 552                 buf = buffer + 4;
 553                 len -= 4;
 554                 while (len && isspace(*buf))
 555                         buf++, len--;
 556                 while (len && isspace(buf[len-1]))
 557                         len--;
 558                 buf[len] = 0;
 559                 memcpy(ref_buffer, buf, len + 1);
 560                 ref = ref_buffer;
 561                 if (flag)
 562                         *flag |= REF_ISSYMREF;
 563         }
 564         if (len < 40 || get_sha1_hex(buffer, sha1))
 565                 return NULL;
 566         return ref;
 567 }
 568
 569 /* The argument to filter_refs */
 570 struct ref_filter {
 571         const char *pattern;
 572         each_ref_fn *fn;
 573         void *cb_data;
 574 };
 575
 576 int read_ref(const char *ref, unsigned char *sha1)
 577 {
 578         if (resolve_ref(ref, sha1, 1, NULL))
 579                 return 0;
 580         return -1;
 581 }
 582
 583 #define DO_FOR_EACH_INCLUDE_BROKEN 01
 584 static int do_one_ref(const char *base, each_ref_fn fn, int trim,
 585                       int flags, void *cb_data, struct ref_list *entry)
 586 {
 587         if (strncmp(base, entry->name, trim))
 588                 return 0;
 589
 590         if (!(flags & DO_FOR_EACH_INCLUDE_BROKEN)) {
 591                 if (entry->flag & REF_BROKEN)
 592                         return 0; /* ignore dangling symref */
 593                 if (!has_sha1_file(entry->sha1)) {
 594                         error("%s does not point to a valid object!", entry->name);
 595                         return 0;
 596                 }
 597         }
 598         current_ref = entry;
 599         return fn(entry->name + trim, entry->sha1, entry->flag, cb_data);
 600 }
 601
 602 static int filter_refs(const char *ref, const unsigned char *sha, int flags,
 603         void *data)
 604 {
 605         struct ref_filter *filter = (struct ref_filter *)data;
 606         if (fnmatch(filter->pattern, ref, 0))
 607                 return 0;
 608         return filter->fn(ref, sha, flags, filter->cb_data);
 609 }
 610
 611 int peel_ref(const char *ref, unsigned char *sha1)
 612 {
 613         int flag;
 614         unsigned char base[20];
 615         struct object *o;
 616
 617         if (current_ref && (current_ref->name == ref
 618                 || !strcmp(current_ref->name, ref))) {
 619                 if (current_ref->flag & REF_KNOWS_PEELED) {
 620                         hashcpy(sha1, current_ref->peeled);
 621                         return 0;
 622                 }
 623                 hashcpy(base, current_ref->sha1);
 624                 goto fallback;
 625         }
 626
 627         if (!resolve_ref(ref, base, 1, &flag))
 628                 return -1;
 629
 630         if ((flag & REF_ISPACKED)) {
 631                 struct ref_list *list = get_packed_refs(NULL);
 632
 633                 while (list) {
 634                         if (!strcmp(list->name, ref)) {
 635                                 if (list->flag & REF_KNOWS_PEELED) {
 636                                         hashcpy(sha1, list->peeled);
 637                                         return 0;
 638                                 }
 639                                 /* older pack-refs did not leave peeled ones */
 640                                 break;
 641                         }
 642                         list = list->next;
 643                 }
 644         }
 645
 646 fallback:
 647         o = parse_object(base);
 648         if (o && o->type == OBJ_TAG) {
 649                 o = deref_tag(o, ref, 0);
 650                 if (o) {
 651                         hashcpy(sha1, o->sha1);
 652                         return 0;
 653                 }
 654         }
 655         return -1;
 656 }
 657
 658 static int do_for_each_ref(const char *submodule, const char *base, each_ref_fn fn,
 659                            int trim, int flags, void *cb_data)
 660 {
 661         int retval = 0;
 662         struct ref_list *packed = get_packed_refs(submodule);
 663         struct ref_list *loose = get_loose_refs(submodule);
 664
 665         struct ref_list *extra;
 666
 667         for (extra = extra_refs; extra; extra = extra->next)
 668                 retval = do_one_ref(base, fn, trim, flags, cb_data, extra);
 669
 670         while (packed && loose) {
 671                 struct ref_list *entry;
 672                 int cmp = strcmp(packed->name, loose->name);
 673                 if (!cmp) {
 674                         packed = packed->next;
 675                         continue;
 676                 }
 677                 if (cmp > 0) {
 678                         entry = loose;
 679                         loose = loose->next;
 680                 } else {
 681                         entry = packed;
 682                         packed = packed->next;
 683                 }
 684                 retval = do_one_ref(base, fn, trim, flags, cb_data, entry);
 685                 if (retval)
 686                         goto end_each;
 687         }
 688
 689         for (packed = packed ? packed : loose; packed; packed = packed->next) {
 690                 retval = do_one_ref(base, fn, trim, flags, cb_data, packed);
 691                 if (retval)
 692                         goto end_each;
 693         }
 694
 695 end_each:
 696         current_ref = NULL;
 697         return retval;
 698 }
 699
 700
 701 static int do_head_ref(const char *submodule, each_ref_fn fn, void *cb_data)
 702 {
 703         unsigned char sha1[20];
 704         int flag;
 705
 706         if (submodule) {
 707                 if (resolve_gitlink_ref(submodule, "HEAD", sha1) == 0)
 708                         return fn("HEAD", sha1, 0, cb_data);
 709
 710                 return 0;
 711         }
 712
 713         if (resolve_ref("HEAD", sha1, 1, &flag))
 714                 return fn("HEAD", sha1, flag, cb_data);
 715
 716         return 0;
 717 }
 718
 719 int head_ref(each_ref_fn fn, void *cb_data)
 720 {
 721         return do_head_ref(NULL, fn, cb_data);
 722 }
 723
 724 int head_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
 725 {
 726         return do_head_ref(submodule, fn, cb_data);
 727 }
 728
 729 int for_each_ref(each_ref_fn fn, void *cb_data)
 730 {
 731         return do_for_each_ref(NULL, "refs/", fn, 0, 0, cb_data);
 732 }
 733
 734 int for_each_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
 735 {
 736         return do_for_each_ref(submodule, "refs/", fn, 0, 0, cb_data);
 737 }
 738
 739 int for_each_ref_in(const char *prefix, each_ref_fn fn, void *cb_data)
 740 {
 741         return do_for_each_ref(NULL, prefix, fn, strlen(prefix), 0, cb_data);
 742 }
 743
 744 int for_each_ref_in_submodule(const char *submodule, const char *prefix,
 745                 each_ref_fn fn, void *cb_data)
 746 {
 747         return do_for_each_ref(submodule, prefix, fn, strlen(prefix), 0, cb_data);
 748 }
 749
 750 int for_each_tag_ref(each_ref_fn fn, void *cb_data)
 751 {
 752         return for_each_ref_in("refs/tags/", fn, cb_data);
 753 }
 754
 755 int for_each_tag_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
 756 {
 757         return for_each_ref_in_submodule(submodule, "refs/tags/", fn, cb_data);
 758 }
 759
 760 int for_each_branch_ref(each_ref_fn fn, void *cb_data)
 761 {
 762         return for_each_ref_in("refs/heads/", fn, cb_data);
 763 }
 764
 765 int for_each_branch_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
 766 {
 767         return for_each_ref_in_submodule(submodule, "refs/heads/", fn, cb_data);
 768 }
 769
 770 int for_each_remote_ref(each_ref_fn fn, void *cb_data)
 771 {
 772         return for_each_ref_in("refs/remotes/", fn, cb_data);
 773 }
 774
 775 int for_each_remote_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
 776 {
 777         return for_each_ref_in_submodule(submodule, "refs/remotes/", fn, cb_data);
 778 }
 779
 780 int for_each_replace_ref(each_ref_fn fn, void *cb_data)
 781 {
 782         return do_for_each_ref(NULL, "refs/replace/", fn, 13, 0, cb_data);
 783 }
 784
 785 int for_each_glob_ref_in(each_ref_fn fn, const char *pattern,
 786         const char *prefix, void *cb_data)
 787 {
 788         struct strbuf real_pattern = STRBUF_INIT;
 789         struct ref_filter filter;
 790         int ret;
 791
 792         if (!prefix && prefixcmp(pattern, "refs/"))
 793                 strbuf_addstr(&real_pattern, "refs/");
 794         else if (prefix)
 795                 strbuf_addstr(&real_pattern, prefix);
 796         strbuf_addstr(&real_pattern, pattern);
 797
 798         if (!has_glob_specials(pattern)) {
 799                 /* Append implied '/' '*' if not present. */
 800                 if (real_pattern.buf[real_pattern.len - 1] != '/')
 801                         strbuf_addch(&real_pattern, '/');
 802                 /* No need to check for '*', there is none. */
 803                 strbuf_addch(&real_pattern, '*');
 804         }
 805
 806         filter.pattern = real_pattern.buf;
 807         filter.fn = fn;
 808         filter.cb_data = cb_data;
 809         ret = for_each_ref(filter_refs, &filter);
 810
 811         strbuf_release(&real_pattern);
 812         return ret;
 813 }
 814
 815 int for_each_glob_ref(each_ref_fn fn, const char *pattern, void *cb_data)
 816 {
 817         return for_each_glob_ref_in(fn, pattern, NULL, cb_data);
 818 }
 819
 820 int for_each_rawref(each_ref_fn fn, void *cb_data)
 821 {
 822         return do_for_each_ref(NULL, "refs/", fn, 0,
 823                                DO_FOR_EACH_INCLUDE_BROKEN, cb_data);
 824 }
 825
 826 /*
 827  * Make sure "ref" is something reasonable to have under ".git/refs/";
 828  * We do not like it if:
 829  *
 830  * - any path component of it begins with ".", or
 831  * - it has double dots "..", or
 832  * - it has ASCII control character, "~", "^", ":" or SP, anywhere, or
 833  * - it ends with a "/".
 834  * - it ends with ".lock"
 835  * - it contains a "\" (backslash)
 836  */
 837
 838 static inline int bad_ref_char(int ch)
 839 {
 840         if (((unsigned) ch) <= ' ' ||
 841             ch == '~' || ch == '^' || ch == ':' || ch == '\\')
 842                 return 1;
 843         /* 2.13 Pattern Matching Notation */
 844         if (ch == '?' || ch == '[') /* Unsupported */
 845                 return 1;
 846         if (ch == '*') /* Supported at the end */
 847                 return 2;
 848         return 0;
 849 }
 850
 851 int check_ref_format(const char *ref)
 852 {
 853         int ch, level, bad_type, last;
 854         int ret = CHECK_REF_FORMAT_OK;
 855         const char *cp = ref;
 856
 857         level = 0;
 858         while (1) {
 859                 while ((ch = *cp++) == '/')
 860                         ; /* tolerate duplicated slashes */
 861                 if (!ch)
 862                         /* should not end with slashes */
 863                         return CHECK_REF_FORMAT_ERROR;
 864
 865                 /* we are at the beginning of the path component */
 866                 if (ch == '.')
 867                         return CHECK_REF_FORMAT_ERROR;
 868                 bad_type = bad_ref_char(ch);
 869                 if (bad_type) {
 870                         if (bad_type == 2 && (!*cp || *cp == '/') &&
 871                             ret == CHECK_REF_FORMAT_OK)
 872                                 ret = CHECK_REF_FORMAT_WILDCARD;
 873                         else
 874                                 return CHECK_REF_FORMAT_ERROR;
 875                 }
 876
 877                 last = ch;
 878                 /* scan the rest of the path component */
 879                 while ((ch = *cp++) != 0) {
 880                         bad_type = bad_ref_char(ch);
 881                         if (bad_type)
 882                                 return CHECK_REF_FORMAT_ERROR;
 883                         if (ch == '/')
 884                                 break;
 885                         if (last == '.' && ch == '.')
 886                                 return CHECK_REF_FORMAT_ERROR;
 887                         if (last == '@' && ch == '{')
 888                                 return CHECK_REF_FORMAT_ERROR;
 889                         last = ch;
 890                 }
 891                 level++;
 892                 if (!ch) {
 893                         if (ref <= cp - 2 && cp[-2] == '.')
 894                                 return CHECK_REF_FORMAT_ERROR;
 895                         if (level < 2)
 896                                 return CHECK_REF_FORMAT_ONELEVEL;
 897                         if (has_extension(ref, ".lock"))
 898                                 return CHECK_REF_FORMAT_ERROR;
 899                         return ret;
 900                 }
 901         }
 902 }
 903
 904 const char *prettify_refname(const char *name)
 905 {
 906         return name + (
 907                 !prefixcmp(name, "refs/heads/") ? 11 :
 908                 !prefixcmp(name, "refs/tags/") ? 10 :
 909                 !prefixcmp(name, "refs/remotes/") ? 13 :
 910                 0);
 911 }
 912
 913 const char *ref_rev_parse_rules[] = {
 914         "%.*s",
 915         "refs/%.*s",
 916         "refs/tags/%.*s",
 917         "refs/heads/%.*s",
 918         "refs/remotes/%.*s",
 919         "refs/remotes/%.*s/HEAD",
 920         NULL
 921 };
 922
 923 const char *ref_fetch_rules[] = {
 924         "%.*s",
 925         "refs/%.*s",
 926         "refs/heads/%.*s",
 927         NULL
 928 };
 929
 930 int refname_match(const char *abbrev_name, const char *full_name, const char **rules)
 931 {
 932         const char **p;
 933         const int abbrev_name_len = strlen(abbrev_name);
 934
 935         for (p = rules; *p; p++) {
 936                 if (!strcmp(full_name, mkpath(*p, abbrev_name_len, abbrev_name))) {
 937                         return 1;
 938                 }
 939         }
 940
 941         return 0;
 942 }
 943
 944 static struct ref_lock *verify_lock(struct ref_lock *lock,
 945         const unsigned char *old_sha1, int mustexist)
 946 {
 947         if (!resolve_ref(lock->ref_name, lock->old_sha1, mustexist, NULL)) {
 948                 error("Can't verify ref %s", lock->ref_name);
 949                 unlock_ref(lock);
 950                 return NULL;
 951         }
 952         if (hashcmp(lock->old_sha1, old_sha1)) {
 953                 error("Ref %s is at %s but expected %s", lock->ref_name,
 954                         sha1_to_hex(lock->old_sha1), sha1_to_hex(old_sha1));
 955                 unlock_ref(lock);
 956                 return NULL;
 957         }
 958         return lock;
 959 }
 960
 961 static int remove_empty_directories(const char *file)
 962 {
 963         /* we want to create a file but there is a directory there;
 964          * if that is an empty directory (or a directory that contains
 965          * only empty directories), remove them.
 966          */
 967         struct strbuf path;
 968         int result;
 969
 970         strbuf_init(&path, 20);
 971         strbuf_addstr(&path, file);
 972
 973         result = remove_dir_recursively(&path, REMOVE_DIR_EMPTY_ONLY);
 974
 975         strbuf_release(&path);
 976
 977         return result;
 978 }
 979
 980 static int is_refname_available(const char *ref, const char *oldref,
 981                                 struct ref_list *list, int quiet)
 982 {
 983         int namlen = strlen(ref); /* e.g. 'foo/bar' */
 984         while (list) {
 985                 /* list->name could be 'foo' or 'foo/bar/baz' */
 986                 if (!oldref || strcmp(oldref, list->name)) {
 987                         int len = strlen(list->name);
 988                         int cmplen = (namlen < len) ? namlen : len;
 989                         const char *lead = (namlen < len) ? list->name : ref;
 990                         if (!strncmp(ref, list->name, cmplen) &&
 991                             lead[cmplen] == '/') {
 992                                 if (!quiet)
 993                                         error("'%s' exists; cannot create '%s'",
 994                                               list->name, ref);
 995                                 return 0;
 996                         }
 997                 }
 998                 list = list->next;
 999         }
1000         return 1;
1001 }
1002
1003 static struct ref_lock *lock_ref_sha1_basic(const char *ref, const unsigned char *old_sha1, int flags, int *type_p)
1004 {
1005         char *ref_file;
1006         const char *orig_ref = ref;
1007         struct ref_lock *lock;
1008         int last_errno = 0;
1009         int type, lflags;
1010         int mustexist = (old_sha1 && !is_null_sha1(old_sha1));
1011         int missing = 0;
1012
1013         lock = xcalloc(1, sizeof(struct ref_lock));
1014         lock->lock_fd = -1;
1015
1016         ref = resolve_ref(ref, lock->old_sha1, mustexist, &type);
1017         if (!ref && errno == EISDIR) {
1018                 /* we are trying to lock foo but we used to
1019                  * have foo/bar which now does not exist;
1020                  * it is normal for the empty directory 'foo'
1021                  * to remain.
1022                  */
1023                 ref_file = git_path("%s", orig_ref);
1024                 if (remove_empty_directories(ref_file)) {
1025                         last_errno = errno;
1026                         error("there are still refs under '%s'", orig_ref);
1027                         goto error_return;
1028                 }
1029                 ref = resolve_ref(orig_ref, lock->old_sha1, mustexist, &type);
1030         }
1031         if (type_p)
1032             *type_p = type;
1033         if (!ref) {
1034                 last_errno = errno;
1035                 error("unable to resolve reference %s: %s",
1036                         orig_ref, strerror(errno));
1037                 goto error_return;
1038         }
1039         missing = is_null_sha1(lock->old_sha1);
1040         /* When the ref did not exist and we are creating it,
1041          * make sure there is no existing ref that is packed
1042          * whose name begins with our refname, nor a ref whose
1043          * name is a proper prefix of our refname.
1044          */
1045         if (missing &&
1046              !is_refname_available(ref, NULL, get_packed_refs(NULL), 0)) {
1047                 last_errno = ENOTDIR;
1048                 goto error_return;
1049         }
1050
1051         lock->lk = xcalloc(1, sizeof(struct lock_file));
1052
1053         lflags = LOCK_DIE_ON_ERROR;
1054         if (flags & REF_NODEREF) {
1055                 ref = orig_ref;
1056                 lflags |= LOCK_NODEREF;
1057         }
1058         lock->ref_name = xstrdup(ref);
1059         lock->orig_ref_name = xstrdup(orig_ref);
1060         ref_file = git_path("%s", ref);
1061         if (missing)
1062                 lock->force_write = 1;
1063         if ((flags & REF_NODEREF) && (type & REF_ISSYMREF))
1064                 lock->force_write = 1;
1065
1066         if (safe_create_leading_directories(ref_file)) {
1067                 last_errno = errno;
1068                 error("unable to create directory for %s", ref_file);
1069                 goto error_return;
1070         }
1071
1072         lock->lock_fd = hold_lock_file_for_update(lock->lk, ref_file, lflags);
1073         return old_sha1 ? verify_lock(lock, old_sha1, mustexist) : lock;
1074
1075  error_return:
1076         unlock_ref(lock);
1077         errno = last_errno;
1078         return NULL;
1079 }
1080
1081 struct ref_lock *lock_ref_sha1(const char *ref, const unsigned char *old_sha1)
1082 {
1083         char refpath[PATH_MAX];
1084         if (check_ref_format(ref))
1085                 return NULL;
1086         strcpy(refpath, mkpath("refs/%s", ref));
1087         return lock_ref_sha1_basic(refpath, old_sha1, 0, NULL);
1088 }
1089
1090 struct ref_lock *lock_any_ref_for_update(const char *ref, const unsigned char *old_sha1, int flags)
1091 {
1092         switch (check_ref_format(ref)) {
1093         default:
1094                 return NULL;
1095         case 0:
1096         case CHECK_REF_FORMAT_ONELEVEL:
1097                 return lock_ref_sha1_basic(ref, old_sha1, flags, NULL);
1098         }
1099 }
1100
1101 static struct lock_file packlock;
1102
1103 static int repack_without_ref(const char *refname)
1104 {
1105         struct ref_list *list, *packed_ref_list;
1106         int fd;
1107         int found = 0;
1108
1109         packed_ref_list = get_packed_refs(NULL);
1110         for (list = packed_ref_list; list; list = list->next) {
1111                 if (!strcmp(refname, list->name)) {
1112                         found = 1;
1113                         break;
1114                 }
1115         }
1116         if (!found)
1117                 return 0;
1118         fd = hold_lock_file_for_update(&packlock, git_path("packed-refs"), 0);
1119         if (fd < 0) {
1120                 unable_to_lock_error(git_path("packed-refs"), errno);
1121                 return error("cannot delete '%s' from packed refs", refname);
1122         }
1123
1124         for (list = packed_ref_list; list; list = list->next) {
1125                 char line[PATH_MAX + 100];
1126                 int len;
1127
1128                 if (!strcmp(refname, list->name))
1129                         continue;
1130                 len = snprintf(line, sizeof(line), "%s %s\n",
1131                                sha1_to_hex(list->sha1), list->name);
1132                 /* this should not happen but just being defensive */
1133                 if (len > sizeof(line))
1134                         die("too long a refname '%s'", list->name);
1135                 write_or_die(fd, line, len);
1136         }
1137         return commit_lock_file(&packlock);
1138 }
1139
1140 int delete_ref(const char *refname, const unsigned char *sha1, int delopt)
1141 {
1142         struct ref_lock *lock;
1143         int err, i = 0, ret = 0, flag = 0;
1144
1145         lock = lock_ref_sha1_basic(refname, sha1, 0, &flag);
1146         if (!lock)
1147                 return 1;
1148         if (!(flag & REF_ISPACKED) || flag & REF_ISSYMREF) {
1149                 /* loose */
1150                 const char *path;
1151
1152                 if (!(delopt & REF_NODEREF)) {
1153                         i = strlen(lock->lk->filename) - 5; /* .lock */
1154                         lock->lk->filename[i] = 0;
1155                         path = lock->lk->filename;
1156                 } else {
1157                         path = git_path("%s", refname);
1158                 }
1159                 err = unlink_or_warn(path);
1160                 if (err && errno != ENOENT)
1161                         ret = 1;
1162
1163                 if (!(delopt & REF_NODEREF))
1164                         lock->lk->filename[i] = '.';
1165         }
1166         /* removing the loose one could have resurrected an earlier
1167          * packed one.  Also, if it was not loose we need to repack
1168          * without it.
1169          */
1170         ret |= repack_without_ref(refname);
1171
1172         unlink_or_warn(git_path("logs/%s", lock->ref_name));
1173         invalidate_cached_refs();
1174         unlock_ref(lock);
1175         return ret;
1176 }
1177
1178 /*
1179  * People using contrib's git-new-workdir have .git/logs/refs ->
1180  * /some/other/path/.git/logs/refs, and that may live on another device.
1181  *
1182  * IOW, to avoid cross device rename errors, the temporary renamed log must
1183  * live into logs/refs.
1184  */
1185 #define TMP_RENAMED_LOG  "logs/refs/.tmp-renamed-log"
1186
1187 int rename_ref(const char *oldref, const char *newref, const char *logmsg)
1188 {
1189         static const char renamed_ref[] = "RENAMED-REF";
1190         unsigned char sha1[20], orig_sha1[20];
1191         int flag = 0, logmoved = 0;
1192         struct ref_lock *lock;
1193         struct stat loginfo;
1194         int log = !lstat(git_path("logs/%s", oldref), &loginfo);
1195         const char *symref = NULL;
1196
1197         if (log && S_ISLNK(loginfo.st_mode))
1198                 return error("reflog for %s is a symlink", oldref);
1199
1200         symref = resolve_ref(oldref, orig_sha1, 1, &flag);
1201         if (flag & REF_ISSYMREF)
1202                 return error("refname %s is a symbolic ref, renaming it is not supported",
1203                         oldref);
1204         if (!symref)
1205                 return error("refname %s not found", oldref);
1206
1207         if (!is_refname_available(newref, oldref, get_packed_refs(NULL), 0))
1208                 return 1;
1209
1210         if (!is_refname_available(newref, oldref, get_loose_refs(NULL), 0))
1211                 return 1;
1212
1213         lock = lock_ref_sha1_basic(renamed_ref, NULL, 0, NULL);
1214         if (!lock)
1215                 return error("unable to lock %s", renamed_ref);
1216         lock->force_write = 1;
1217         if (write_ref_sha1(lock, orig_sha1, logmsg))
1218                 return error("unable to save current sha1 in %s", renamed_ref);
1219
1220         if (log && rename(git_path("logs/%s", oldref), git_path(TMP_RENAMED_LOG)))
1221                 return error("unable to move logfile logs/%s to "TMP_RENAMED_LOG": %s",
1222                         oldref, strerror(errno));
1223
1224         if (delete_ref(oldref, orig_sha1, REF_NODEREF)) {
1225                 error("unable to delete old %s", oldref);
1226                 goto rollback;
1227         }
1228
1229         if (resolve_ref(newref, sha1, 1, &flag) && delete_ref(newref, sha1, REF_NODEREF)) {
1230                 if (errno==EISDIR) {
1231                         if (remove_empty_directories(git_path("%s", newref))) {
1232                                 error("Directory not empty: %s", newref);
1233                                 goto rollback;
1234                         }
1235                 } else {
1236                         error("unable to delete existing %s", newref);
1237                         goto rollback;
1238                 }
1239         }
1240
1241         if (log && safe_create_leading_directories(git_path("logs/%s", newref))) {
1242                 error("unable to create directory for %s", newref);
1243                 goto rollback;
1244         }
1245
1246  retry:
1247         if (log && rename(git_path(TMP_RENAMED_LOG), git_path("logs/%s", newref))) {
1248                 if (errno==EISDIR || errno==ENOTDIR) {
1249                         /*
1250                          * rename(a, b) when b is an existing
1251                          * directory ought to result in ISDIR, but
1252                          * Solaris 5.8 gives ENOTDIR.  Sheesh.
1253                          */
1254                         if (remove_empty_directories(git_path("logs/%s", newref))) {
1255                                 error("Directory not empty: logs/%s", newref);
1256                                 goto rollback;
1257                         }
1258                         goto retry;
1259                 } else {
1260                         error("unable to move logfile "TMP_RENAMED_LOG" to logs/%s: %s",
1261                                 newref, strerror(errno));
1262                         goto rollback;
1263                 }
1264         }
1265         logmoved = log;
1266
1267         lock = lock_ref_sha1_basic(newref, NULL, 0, NULL);
1268         if (!lock) {
1269                 error("unable to lock %s for update", newref);
1270                 goto rollback;
1271         }
1272         lock->force_write = 1;
1273         hashcpy(lock->old_sha1, orig_sha1);
1274         if (write_ref_sha1(lock, orig_sha1, logmsg)) {
1275                 error("unable to write current sha1 into %s", newref);
1276                 goto rollback;
1277         }
1278
1279         return 0;
1280
1281  rollback:
1282         lock = lock_ref_sha1_basic(oldref, NULL, 0, NULL);
1283         if (!lock) {
1284                 error("unable to lock %s for rollback", oldref);
1285                 goto rollbacklog;
1286         }
1287
1288         lock->force_write = 1;
1289         flag = log_all_ref_updates;
1290         log_all_ref_updates = 0;
1291         if (write_ref_sha1(lock, orig_sha1, NULL))
1292                 error("unable to write current sha1 into %s", oldref);
1293         log_all_ref_updates = flag;
1294
1295  rollbacklog:
1296         if (logmoved && rename(git_path("logs/%s", newref), git_path("logs/%s", oldref)))
1297                 error("unable to restore logfile %s from %s: %s",
1298                         oldref, newref, strerror(errno));
1299         if (!logmoved && log &&
1300             rename(git_path(TMP_RENAMED_LOG), git_path("logs/%s", oldref)))
1301                 error("unable to restore logfile %s from "TMP_RENAMED_LOG": %s",
1302                         oldref, strerror(errno));
1303
1304         return 1;
1305 }
1306
1307 int close_ref(struct ref_lock *lock)
1308 {
1309         if (close_lock_file(lock->lk))
1310                 return -1;
1311         lock->lock_fd = -1;
1312         return 0;
1313 }
1314
1315 int commit_ref(struct ref_lock *lock)
1316 {
1317         if (commit_lock_file(lock->lk))
1318                 return -1;
1319         lock->lock_fd = -1;
1320         return 0;
1321 }
1322
1323 void unlock_ref(struct ref_lock *lock)
1324 {
1325         /* Do not free lock->lk -- atexit() still looks at them */
1326         if (lock->lk)
1327                 rollback_lock_file(lock->lk);
1328         free(lock->ref_name);
1329         free(lock->orig_ref_name);
1330         free(lock);
1331 }
1332
1333 /*
1334  * copy the reflog message msg to buf, which has been allocated sufficiently
1335  * large, while cleaning up the whitespaces.  Especially, convert LF to space,
1336  * because reflog file is one line per entry.
1337  */
1338 static int copy_msg(char *buf, const char *msg)
1339 {
1340         char *cp = buf;
1341         char c;
1342         int wasspace = 1;
1343
1344         *cp++ = '\t';
1345         while ((c = *msg++)) {
1346                 if (wasspace && isspace(c))
1347                         continue;
1348                 wasspace = isspace(c);
1349                 if (wasspace)
1350                         c = ' ';
1351                 *cp++ = c;
1352         }
1353         while (buf < cp && isspace(cp[-1]))
1354                 cp--;
1355         *cp++ = '\n';
1356         return cp - buf;
1357 }
1358
1359 int log_ref_setup(const char *ref_name, char *logfile, int bufsize)
1360 {
1361         int logfd, oflags = O_APPEND | O_WRONLY;
1362
1363         git_snpath(logfile, bufsize, "logs/%s", ref_name);
1364         if (log_all_ref_updates &&
1365             (!prefixcmp(ref_name, "refs/heads/") ||
1366              !prefixcmp(ref_name, "refs/remotes/") ||
1367              !prefixcmp(ref_name, "refs/notes/") ||
1368              !strcmp(ref_name, "HEAD"))) {
1369                 if (safe_create_leading_directories(logfile) < 0)
1370                         return error("unable to create directory for %s",
1371                                      logfile);
1372                 oflags |= O_CREAT;
1373         }
1374
1375         logfd = open(logfile, oflags, 0666);
1376         if (logfd < 0) {
1377                 if (!(oflags & O_CREAT) && errno == ENOENT)
1378                         return 0;
1379
1380                 if ((oflags & O_CREAT) && errno == EISDIR) {
1381                         if (remove_empty_directories(logfile)) {
1382                                 return error("There are still logs under '%s'",
1383                                              logfile);
1384                         }
1385                         logfd = open(logfile, oflags, 0666);
1386                 }
1387
1388                 if (logfd < 0)
1389                         return error("Unable to append to %s: %s",
1390                                      logfile, strerror(errno));
1391         }
1392
1393         adjust_shared_perm(logfile);
1394         close(logfd);
1395         return 0;
1396 }
1397
1398 static int log_ref_write(const char *ref_name, const unsigned char *old_sha1,
1399                          const unsigned char *new_sha1, const char *msg)
1400 {
1401         int logfd, result, written, oflags = O_APPEND | O_WRONLY;
1402         unsigned maxlen, len;
1403         int msglen;
1404         char log_file[PATH_MAX];
1405         char *logrec;
1406         const char *committer;
1407
1408         if (log_all_ref_updates < 0)
1409                 log_all_ref_updates = !is_bare_repository();
1410
1411         result = log_ref_setup(ref_name, log_file, sizeof(log_file));
1412         if (result)
1413                 return result;
1414
1415         logfd = open(log_file, oflags);
1416         if (logfd < 0)
1417                 return 0;
1418         msglen = msg ? strlen(msg) : 0;
1419         committer = git_committer_info(0);
1420         maxlen = strlen(committer) + msglen + 100;
1421         logrec = xmalloc(maxlen);
1422         len = sprintf(logrec, "%s %s %s\n",
1423                       sha1_to_hex(old_sha1),
1424                       sha1_to_hex(new_sha1),
1425                       committer);
1426         if (msglen)
1427                 len += copy_msg(logrec + len - 1, msg) - 1;
1428         written = len <= maxlen ? write_in_full(logfd, logrec, len) : -1;
1429         free(logrec);
1430         if (close(logfd) != 0 || written != len)
1431                 return error("Unable to append to %s", log_file);
1432         return 0;
1433 }
1434
1435 static int is_branch(const char *refname)
1436 {
1437         return !strcmp(refname, "HEAD") || !prefixcmp(refname, "refs/heads/");
1438 }
1439
1440 int write_ref_sha1(struct ref_lock *lock,
1441         const unsigned char *sha1, const char *logmsg)
1442 {
1443         static char term = '\n';
1444         struct object *o;
1445
1446         if (!lock)
1447                 return -1;
1448         if (!lock->force_write && !hashcmp(lock->old_sha1, sha1)) {
1449                 unlock_ref(lock);
1450                 return 0;
1451         }
1452         o = parse_object(sha1);
1453         if (!o) {
1454                 error("Trying to write ref %s with nonexistant object %s",
1455                         lock->ref_name, sha1_to_hex(sha1));
1456                 unlock_ref(lock);
1457                 return -1;
1458         }
1459         if (o->type != OBJ_COMMIT && is_branch(lock->ref_name)) {
1460                 error("Trying to write non-commit object %s to branch %s",
1461                         sha1_to_hex(sha1), lock->ref_name);
1462                 unlock_ref(lock);
1463                 return -1;
1464         }
1465         if (write_in_full(lock->lock_fd, sha1_to_hex(sha1), 40) != 40 ||
1466             write_in_full(lock->lock_fd, &term, 1) != 1
1467                 || close_ref(lock) < 0) {
1468                 error("Couldn't write %s", lock->lk->filename);
1469                 unlock_ref(lock);
1470                 return -1;
1471         }
1472         invalidate_cached_refs();
1473         if (log_ref_write(lock->ref_name, lock->old_sha1, sha1, logmsg) < 0 ||
1474             (strcmp(lock->ref_name, lock->orig_ref_name) &&
1475              log_ref_write(lock->orig_ref_name, lock->old_sha1, sha1, logmsg) < 0)) {
1476                 unlock_ref(lock);
1477                 return -1;
1478         }
1479         if (strcmp(lock->orig_ref_name, "HEAD") != 0) {
1480                 /*
1481                  * Special hack: If a branch is updated directly and HEAD
1482                  * points to it (may happen on the remote side of a push
1483                  * for example) then logically the HEAD reflog should be
1484                  * updated too.
1485                  * A generic solution implies reverse symref information,
1486                  * but finding all symrefs pointing to the given branch
1487                  * would be rather costly for this rare event (the direct
1488                  * update of a branch) to be worth it.  So let's cheat and
1489                  * check with HEAD only which should cover 99% of all usage
1490                  * scenarios (even 100% of the default ones).
1491                  */
1492                 unsigned char head_sha1[20];
1493                 int head_flag;
1494                 const char *head_ref;
1495                 head_ref = resolve_ref("HEAD", head_sha1, 1, &head_flag);
1496                 if (head_ref && (head_flag & REF_ISSYMREF) &&
1497                     !strcmp(head_ref, lock->ref_name))
1498                         log_ref_write("HEAD", lock->old_sha1, sha1, logmsg);
1499         }
1500         if (commit_ref(lock)) {
1501                 error("Couldn't set %s", lock->ref_name);
1502                 unlock_ref(lock);
1503                 return -1;
1504         }
1505         unlock_ref(lock);
1506         return 0;
1507 }
1508
1509 int create_symref(const char *ref_target, const char *refs_heads_master,
1510                   const char *logmsg)
1511 {
1512         const char *lockpath;
1513         char ref[1000];
1514         int fd, len, written;
1515         char *git_HEAD = git_pathdup("%s", ref_target);
1516         unsigned char old_sha1[20], new_sha1[20];
1517
1518         if (logmsg && read_ref(ref_target, old_sha1))
1519                 hashclr(old_sha1);
1520
1521         if (safe_create_leading_directories(git_HEAD) < 0)
1522                 return error("unable to create directory for %s", git_HEAD);
1523
1524 #ifndef NO_SYMLINK_HEAD
1525         if (prefer_symlink_refs) {
1526                 unlink(git_HEAD);
1527                 if (!symlink(refs_heads_master, git_HEAD))
1528                         goto done;
1529                 fprintf(stderr, "no symlink - falling back to symbolic ref\n");
1530         }
1531 #endif
1532
1533         len = snprintf(ref, sizeof(ref), "ref: %s\n", refs_heads_master);
1534         if (sizeof(ref) <= len) {
1535                 error("refname too long: %s", refs_heads_master);
1536                 goto error_free_return;
1537         }
1538         lockpath = mkpath("%s.lock", git_HEAD);
1539         fd = open(lockpath, O_CREAT | O_EXCL | O_WRONLY, 0666);
1540         if (fd < 0) {
1541                 error("Unable to open %s for writing", lockpath);
1542                 goto error_free_return;
1543         }
1544         written = write_in_full(fd, ref, len);
1545         if (close(fd) != 0 || written != len) {
1546                 error("Unable to write to %s", lockpath);
1547                 goto error_unlink_return;
1548         }
1549         if (rename(lockpath, git_HEAD) < 0) {
1550                 error("Unable to create %s", git_HEAD);
1551                 goto error_unlink_return;
1552         }
1553         if (adjust_shared_perm(git_HEAD)) {
1554                 error("Unable to fix permissions on %s", lockpath);
1555         error_unlink_return:
1556                 unlink_or_warn(lockpath);
1557         error_free_return:
1558                 free(git_HEAD);
1559                 return -1;
1560         }
1561
1562 #ifndef NO_SYMLINK_HEAD
1563         done:
1564 #endif
1565         if (logmsg && !read_ref(refs_heads_master, new_sha1))
1566                 log_ref_write(ref_target, old_sha1, new_sha1, logmsg);
1567
1568         free(git_HEAD);
1569         return 0;
1570 }
1571
1572 static char *ref_msg(const char *line, const char *endp)
1573 {
1574         const char *ep;
1575         line += 82;
1576         ep = memchr(line, '\n', endp - line);
1577         if (!ep)
1578                 ep = endp;
1579         return xmemdupz(line, ep - line);
1580 }
1581
1582 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)
1583 {
1584         const char *logfile, *logdata, *logend, *rec, *lastgt, *lastrec;
1585         char *tz_c;
1586         int logfd, tz, reccnt = 0;
1587         struct stat st;
1588         unsigned long date;
1589         unsigned char logged_sha1[20];
1590         void *log_mapped;
1591         size_t mapsz;
1592
1593         logfile = git_path("logs/%s", ref);
1594         logfd = open(logfile, O_RDONLY, 0);
1595         if (logfd < 0)
1596                 die_errno("Unable to read log '%s'", logfile);
1597         fstat(logfd, &st);
1598         if (!st.st_size)
1599                 die("Log %s is empty.", logfile);
1600         mapsz = xsize_t(st.st_size);
1601         log_mapped = xmmap(NULL, mapsz, PROT_READ, MAP_PRIVATE, logfd, 0);
1602         logdata = log_mapped;
1603         close(logfd);
1604
1605         lastrec = NULL;
1606         rec = logend = logdata + st.st_size;
1607         while (logdata < rec) {
1608                 reccnt++;
1609                 if (logdata < rec && *(rec-1) == '\n')
1610                         rec--;
1611                 lastgt = NULL;
1612                 while (logdata < rec && *(rec-1) != '\n') {
1613                         rec--;
1614                         if (*rec == '>')
1615                                 lastgt = rec;
1616                 }
1617                 if (!lastgt)
1618                         die("Log %s is corrupt.", logfile);
1619                 date = strtoul(lastgt + 1, &tz_c, 10);
1620                 if (date <= at_time || cnt == 0) {
1621                         tz = strtoul(tz_c, NULL, 10);
1622                         if (msg)
1623                                 *msg = ref_msg(rec, logend);
1624                         if (cutoff_time)
1625                                 *cutoff_time = date;
1626                         if (cutoff_tz)
1627                                 *cutoff_tz = tz;
1628                         if (cutoff_cnt)
1629                                 *cutoff_cnt = reccnt - 1;
1630                         if (lastrec) {
1631                                 if (get_sha1_hex(lastrec, logged_sha1))
1632                                         die("Log %s is corrupt.", logfile);
1633                                 if (get_sha1_hex(rec + 41, sha1))
1634                                         die("Log %s is corrupt.", logfile);
1635                                 if (hashcmp(logged_sha1, sha1)) {
1636                                         warning("Log %s has gap after %s.",
1637                                                 logfile, show_date(date, tz, DATE_RFC2822));
1638                                 }
1639                         }
1640                         else if (date == at_time) {
1641                                 if (get_sha1_hex(rec + 41, sha1))
1642                                         die("Log %s is corrupt.", logfile);
1643                         }
1644                         else {
1645                                 if (get_sha1_hex(rec + 41, logged_sha1))
1646                                         die("Log %s is corrupt.", logfile);
1647                                 if (hashcmp(logged_sha1, sha1)) {
1648                                         warning("Log %s unexpectedly ended on %s.",
1649                                                 logfile, show_date(date, tz, DATE_RFC2822));
1650                                 }
1651                         }
1652                         munmap(log_mapped, mapsz);
1653                         return 0;
1654                 }
1655                 lastrec = rec;
1656                 if (cnt > 0)
1657                         cnt--;
1658         }
1659
1660         rec = logdata;
1661         while (rec < logend && *rec != '>' && *rec != '\n')
1662                 rec++;
1663         if (rec == logend || *rec == '\n')
1664                 die("Log %s is corrupt.", logfile);
1665         date = strtoul(rec + 1, &tz_c, 10);
1666         tz = strtoul(tz_c, NULL, 10);
1667         if (get_sha1_hex(logdata, sha1))
1668                 die("Log %s is corrupt.", logfile);
1669         if (is_null_sha1(sha1)) {
1670                 if (get_sha1_hex(logdata + 41, sha1))
1671                         die("Log %s is corrupt.", logfile);
1672         }
1673         if (msg)
1674                 *msg = ref_msg(logdata, logend);
1675         munmap(log_mapped, mapsz);
1676
1677         if (cutoff_time)
1678                 *cutoff_time = date;
1679         if (cutoff_tz)
1680                 *cutoff_tz = tz;
1681         if (cutoff_cnt)
1682                 *cutoff_cnt = reccnt;
1683         return 1;
1684 }
1685
1686 int for_each_recent_reflog_ent(const char *ref, each_reflog_ent_fn fn, long ofs, void *cb_data)
1687 {
1688         const char *logfile;
1689         FILE *logfp;
1690         struct strbuf sb = STRBUF_INIT;
1691         int ret = 0;
1692
1693         logfile = git_path("logs/%s", ref);
1694         logfp = fopen(logfile, "r");
1695         if (!logfp)
1696                 return -1;
1697
1698         if (ofs) {
1699                 struct stat statbuf;
1700                 if (fstat(fileno(logfp), &statbuf) ||
1701                     statbuf.st_size < ofs ||
1702                     fseek(logfp, -ofs, SEEK_END) ||
1703                     strbuf_getwholeline(&sb, logfp, '\n')) {
1704                         fclose(logfp);
1705                         strbuf_release(&sb);
1706                         return -1;
1707                 }
1708         }
1709
1710         while (!strbuf_getwholeline(&sb, logfp, '\n')) {
1711                 unsigned char osha1[20], nsha1[20];
1712                 char *email_end, *message;
1713                 unsigned long timestamp;
1714                 int tz;
1715
1716                 /* old SP new SP name <email> SP time TAB msg LF */
1717                 if (sb.len < 83 || sb.buf[sb.len - 1] != '\n' ||
1718                     get_sha1_hex(sb.buf, osha1) || sb.buf[40] != ' ' ||
1719                     get_sha1_hex(sb.buf + 41, nsha1) || sb.buf[81] != ' ' ||
1720                     !(email_end = strchr(sb.buf + 82, '>')) ||
1721                     email_end[1] != ' ' ||
1722                     !(timestamp = strtoul(email_end + 2, &message, 10)) ||
1723                     !message || message[0] != ' ' ||
1724                     (message[1] != '+' && message[1] != '-') ||
1725                     !isdigit(message[2]) || !isdigit(message[3]) ||
1726                     !isdigit(message[4]) || !isdigit(message[5]))
1727                         continue; /* corrupt? */
1728                 email_end[1] = '\0';
1729                 tz = strtol(message + 1, NULL, 10);
1730                 if (message[6] != '\t')
1731                         message += 6;
1732                 else
1733                         message += 7;
1734                 ret = fn(osha1, nsha1, sb.buf + 82, timestamp, tz, message,
1735                          cb_data);
1736                 if (ret)
1737                         break;
1738         }
1739         fclose(logfp);
1740         strbuf_release(&sb);
1741         return ret;
1742 }
1743
1744 int for_each_reflog_ent(const char *ref, each_reflog_ent_fn fn, void *cb_data)
1745 {
1746         return for_each_recent_reflog_ent(ref, fn, 0, cb_data);
1747 }
1748
1749 static int do_for_each_reflog(const char *base, each_ref_fn fn, void *cb_data)
1750 {
1751         DIR *dir = opendir(git_path("logs/%s", base));
1752         int retval = 0;
1753
1754         if (dir) {
1755                 struct dirent *de;
1756                 int baselen = strlen(base);
1757                 char *log = xmalloc(baselen + 257);
1758
1759                 memcpy(log, base, baselen);
1760                 if (baselen && base[baselen-1] != '/')
1761                         log[baselen++] = '/';
1762
1763                 while ((de = readdir(dir)) != NULL) {
1764                         struct stat st;
1765                         int namelen;
1766
1767                         if (de->d_name[0] == '.')
1768                                 continue;
1769                         namelen = strlen(de->d_name);
1770                         if (namelen > 255)
1771                                 continue;
1772                         if (has_extension(de->d_name, ".lock"))
1773                                 continue;
1774                         memcpy(log + baselen, de->d_name, namelen+1);
1775                         if (stat(git_path("logs/%s", log), &st) < 0)
1776                                 continue;
1777                         if (S_ISDIR(st.st_mode)) {
1778                                 retval = do_for_each_reflog(log, fn, cb_data);
1779                         } else {
1780                                 unsigned char sha1[20];
1781                                 if (!resolve_ref(log, sha1, 0, NULL))
1782                                         retval = error("bad ref for %s", log);
1783                                 else
1784                                         retval = fn(log, sha1, 0, cb_data);
1785                         }
1786                         if (retval)
1787                                 break;
1788                 }
1789                 free(log);
1790                 closedir(dir);
1791         }
1792         else if (*base)
1793                 return errno;
1794         return retval;
1795 }
1796
1797 int for_each_reflog(each_ref_fn fn, void *cb_data)
1798 {
1799         return do_for_each_reflog("", fn, cb_data);
1800 }
1801
1802 int update_ref(const char *action, const char *refname,
1803                 const unsigned char *sha1, const unsigned char *oldval,
1804                 int flags, enum action_on_err onerr)
1805 {
1806         static struct ref_lock *lock;
1807         lock = lock_any_ref_for_update(refname, oldval, flags);
1808         if (!lock) {
1809                 const char *str = "Cannot lock the ref '%s'.";
1810                 switch (onerr) {
1811                 case MSG_ON_ERR: error(str, refname); break;
1812                 case DIE_ON_ERR: die(str, refname); break;
1813                 case QUIET_ON_ERR: break;
1814                 }
1815                 return 1;
1816         }
1817         if (write_ref_sha1(lock, sha1, action) < 0) {
1818                 const char *str = "Cannot update the ref '%s'.";
1819                 switch (onerr) {
1820                 case MSG_ON_ERR: error(str, refname); break;
1821                 case DIE_ON_ERR: die(str, refname); break;
1822                 case QUIET_ON_ERR: break;
1823                 }
1824                 return 1;
1825         }
1826         return 0;
1827 }
1828
1829 struct ref *find_ref_by_name(const struct ref *list, const char *name)
1830 {
1831         for ( ; list; list = list->next)
1832                 if (!strcmp(list->name, name))
1833                         return (struct ref *)list;
1834         return NULL;
1835 }
1836
1837 /*
1838  * generate a format suitable for scanf from a ref_rev_parse_rules
1839  * rule, that is replace the "%.*s" spec with a "%s" spec
1840  */
1841 static void gen_scanf_fmt(char *scanf_fmt, const char *rule)
1842 {
1843         char *spec;
1844
1845         spec = strstr(rule, "%.*s");
1846         if (!spec || strstr(spec + 4, "%.*s"))
1847                 die("invalid rule in ref_rev_parse_rules: %s", rule);
1848
1849         /* copy all until spec */
1850         strncpy(scanf_fmt, rule, spec - rule);
1851         scanf_fmt[spec - rule] = '\0';
1852         /* copy new spec */
1853         strcat(scanf_fmt, "%s");
1854         /* copy remaining rule */
1855         strcat(scanf_fmt, spec + 4);
1856
1857         return;
1858 }
1859
1860 char *shorten_unambiguous_ref(const char *ref, int strict)
1861 {
1862         int i;
1863         static char **scanf_fmts;
1864         static int nr_rules;
1865         char *short_name;
1866
1867         /* pre generate scanf formats from ref_rev_parse_rules[] */
1868         if (!nr_rules) {
1869                 size_t total_len = 0;
1870
1871                 /* the rule list is NULL terminated, count them first */
1872                 for (; ref_rev_parse_rules[nr_rules]; nr_rules++)
1873                         /* no +1 because strlen("%s") < strlen("%.*s") */
1874                         total_len += strlen(ref_rev_parse_rules[nr_rules]);
1875
1876                 scanf_fmts = xmalloc(nr_rules * sizeof(char *) + total_len);
1877
1878                 total_len = 0;
1879                 for (i = 0; i < nr_rules; i++) {
1880                         scanf_fmts[i] = (char *)&scanf_fmts[nr_rules]
1881                                         + total_len;
1882                         gen_scanf_fmt(scanf_fmts[i], ref_rev_parse_rules[i]);
1883                         total_len += strlen(ref_rev_parse_rules[i]);
1884                 }
1885         }
1886
1887         /* bail out if there are no rules */
1888         if (!nr_rules)
1889                 return xstrdup(ref);
1890
1891         /* buffer for scanf result, at most ref must fit */
1892         short_name = xstrdup(ref);
1893
1894         /* skip first rule, it will always match */
1895         for (i = nr_rules - 1; i > 0 ; --i) {
1896                 int j;
1897                 int rules_to_fail = i;
1898                 int short_name_len;
1899
1900                 if (1 != sscanf(ref, scanf_fmts[i], short_name))
1901                         continue;
1902
1903                 short_name_len = strlen(short_name);
1904
1905                 /*
1906                  * in strict mode, all (except the matched one) rules
1907                  * must fail to resolve to a valid non-ambiguous ref
1908                  */
1909                 if (strict)
1910                         rules_to_fail = nr_rules;
1911
1912                 /*
1913                  * check if the short name resolves to a valid ref,
1914                  * but use only rules prior to the matched one
1915                  */
1916                 for (j = 0; j < rules_to_fail; j++) {
1917                         const char *rule = ref_rev_parse_rules[j];
1918                         unsigned char short_objectname[20];
1919                         char refname[PATH_MAX];
1920
1921                         /* skip matched rule */
1922                         if (i == j)
1923                                 continue;
1924
1925                         /*
1926                          * the short name is ambiguous, if it resolves
1927                          * (with this previous rule) to a valid ref
1928                          * read_ref() returns 0 on success
1929                          */
1930                         mksnpath(refname, sizeof(refname),
1931                                  rule, short_name_len, short_name);
1932                         if (!read_ref(refname, short_objectname))
1933                                 break;
1934                 }
1935
1936                 /*
1937                  * short name is non-ambiguous if all previous rules
1938                  * haven't resolved to a valid ref
1939                  */
1940                 if (j == rules_to_fail)
1941                         return short_name;
1942         }
1943
1944         free(short_name);
1945         return xstrdup(ref);
1946 }