Pileus Git - ~andy/git/blob - 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_entry {
  12         unsigned char flag; /* ISSYMREF? ISPACKED? */
  13         unsigned char sha1[20];
  14         unsigned char peeled[20];
  15         char name[FLEX_ARRAY];
  16 };
  17
  18 struct ref_array {
  19         int nr, alloc;
  20         struct ref_entry **refs;
  21 };
  22
  23 static const char *parse_ref_line(char *line, unsigned char *sha1)
  24 {
  25         /*
  26          * 42: the answer to everything.
  27          *
  28          * In this case, it happens to be the answer to
  29          *  40 (length of sha1 hex representation)
  30          *  +1 (space in between hex and name)
  31          *  +1 (newline at the end of the line)
  32          */
  33         int len = strlen(line) - 42;
  34
  35         if (len <= 0)
  36                 return NULL;
  37         if (get_sha1_hex(line, sha1) < 0)
  38                 return NULL;
  39         if (!isspace(line[40]))
  40                 return NULL;
  41         line += 41;
  42         if (isspace(*line))
  43                 return NULL;
  44         if (line[len] != '\n')
  45                 return NULL;
  46         line[len] = 0;
  47
  48         return line;
  49 }
  50
  51 static void add_ref(const char *name, const unsigned char *sha1,
  52                     int flag, struct ref_array *refs,
  53                     struct ref_entry **new_entry)
  54 {
  55         int len;
  56         struct ref_entry *entry;
  57
  58         /* Allocate it and add it in.. */
  59         len = strlen(name) + 1;
  60         entry = xmalloc(sizeof(struct ref_entry) + len);
  61         hashcpy(entry->sha1, sha1);
  62         hashclr(entry->peeled);
  63         if (check_refname_format(name, REFNAME_ALLOW_ONELEVEL|REFNAME_DOT_COMPONENT))
  64                 die("Reference has invalid format: '%s'", name);
  65         memcpy(entry->name, name, len);
  66         entry->flag = flag;
  67         if (new_entry)
  68                 *new_entry = entry;
  69         ALLOC_GROW(refs->refs, refs->nr + 1, refs->alloc);
  70         refs->refs[refs->nr++] = entry;
  71 }
  72
  73 static int ref_entry_cmp(const void *a, const void *b)
  74 {
  75         struct ref_entry *one = *(struct ref_entry **)a;
  76         struct ref_entry *two = *(struct ref_entry **)b;
  77         return strcmp(one->name, two->name);
  78 }
  79
  80 static void sort_ref_array(struct ref_array *array)
  81 {
  82         int i = 0, j = 1;
  83
  84         /* Nothing to sort unless there are at least two entries */
  85         if (array->nr < 2)
  86                 return;
  87
  88         qsort(array->refs, array->nr, sizeof(*array->refs), ref_entry_cmp);
  89
  90         /* Remove any duplicates from the ref_array */
  91         for (; j < array->nr; j++) {
  92                 struct ref_entry *a = array->refs[i];
  93                 struct ref_entry *b = array->refs[j];
  94                 if (!strcmp(a->name, b->name)) {
  95                         if (hashcmp(a->sha1, b->sha1))
  96                                 die("Duplicated ref, and SHA1s don't match: %s",
  97                                     a->name);
  98                         warning("Duplicated ref: %s", a->name);
  99                         free(b);
 100                         continue;
 101                 }
 102                 i++;
 103                 array->refs[i] = array->refs[j];
 104         }
 105         array->nr = i + 1;
 106 }
 107
 108 static struct ref_entry *search_ref_array(struct ref_array *array, const char *name)
 109 {
 110         struct ref_entry *e, **r;
 111         int len;
 112
 113         if (name == NULL)
 114                 return NULL;
 115
 116         if (!array->nr)
 117                 return NULL;
 118
 119         len = strlen(name) + 1;
 120         e = xmalloc(sizeof(struct ref_entry) + len);
 121         memcpy(e->name, name, len);
 122
 123         r = bsearch(&e, array->refs, array->nr, sizeof(*array->refs), ref_entry_cmp);
 124
 125         free(e);
 126
 127         if (r == NULL)
 128                 return NULL;
 129
 130         return *r;
 131 }
 132
 133 /*
 134  * Future: need to be in "struct repository"
 135  * when doing a full libification.
 136  */
 137 static struct cached_refs {
 138         struct cached_refs *next;
 139         char did_loose;
 140         char did_packed;
 141         struct ref_array loose;
 142         struct ref_array packed;
 143         /* The submodule name, or "" for the main repo. */
 144         char name[FLEX_ARRAY];
 145 } *cached_refs;
 146
 147 static struct ref_entry *current_ref;
 148
 149 static struct ref_array extra_refs;
 150
 151 static void free_ref_array(struct ref_array *array)
 152 {
 153         int i;
 154         for (i = 0; i < array->nr; i++)
 155                 free(array->refs[i]);
 156         free(array->refs);
 157         array->nr = array->alloc = 0;
 158         array->refs = NULL;
 159 }
 160
 161 static void clear_cached_refs(struct cached_refs *ca)
 162 {
 163         if (ca->did_loose)
 164                 free_ref_array(&ca->loose);
 165         if (ca->did_packed)
 166                 free_ref_array(&ca->packed);
 167         ca->did_loose = ca->did_packed = 0;
 168 }
 169
 170 static struct cached_refs *create_cached_refs(const char *submodule)
 171 {
 172         int len;
 173         struct cached_refs *refs;
 174         if (!submodule)
 175                 submodule = "";
 176         len = strlen(submodule) + 1;
 177         refs = xcalloc(1, sizeof(struct cached_refs) + len);
 178         memcpy(refs->name, submodule, len);
 179         return refs;
 180 }
 181
 182 /*
 183  * Return a pointer to a cached_refs for the specified submodule. For
 184  * the main repository, use submodule==NULL. The returned structure
 185  * will be allocated and initialized but not necessarily populated; it
 186  * should not be freed.
 187  */
 188 static struct cached_refs *get_cached_refs(const char *submodule)
 189 {
 190         struct cached_refs *refs = cached_refs;
 191         if (!submodule)
 192                 submodule = "";
 193         while (refs) {
 194                 if (!strcmp(submodule, refs->name))
 195                         return refs;
 196                 refs = refs->next;
 197         }
 198
 199         refs = create_cached_refs(submodule);
 200         refs->next = cached_refs;
 201         cached_refs = refs;
 202         return refs;
 203 }
 204
 205 static void invalidate_cached_refs(void)
 206 {
 207         struct cached_refs *refs = cached_refs;
 208         while (refs) {
 209                 clear_cached_refs(refs);
 210                 refs = refs->next;
 211         }
 212 }
 213
 214 static void read_packed_refs(FILE *f, struct ref_array *array)
 215 {
 216         struct ref_entry *last = NULL;
 217         char refline[PATH_MAX];
 218         int flag = REF_ISPACKED;
 219
 220         while (fgets(refline, sizeof(refline), f)) {
 221                 unsigned char sha1[20];
 222                 const char *name;
 223                 static const char header[] = "# pack-refs with:";
 224
 225                 if (!strncmp(refline, header, sizeof(header)-1)) {
 226                         const char *traits = refline + sizeof(header) - 1;
 227                         if (strstr(traits, " peeled "))
 228                                 flag |= REF_KNOWS_PEELED;
 229                         /* perhaps other traits later as well */
 230                         continue;
 231                 }
 232
 233                 name = parse_ref_line(refline, sha1);
 234                 if (name) {
 235                         add_ref(name, sha1, flag, array, &last);
 236                         continue;
 237                 }
 238                 if (last &&
 239                     refline[0] == '^' &&
 240                     strlen(refline) == 42 &&
 241                     refline[41] == '\n' &&
 242                     !get_sha1_hex(refline + 1, sha1))
 243                         hashcpy(last->peeled, sha1);
 244         }
 245         sort_ref_array(array);
 246 }
 247
 248 void add_extra_ref(const char *name, const unsigned char *sha1, int flag)
 249 {
 250         add_ref(name, sha1, flag, &extra_refs, NULL);
 251 }
 252
 253 void clear_extra_refs(void)
 254 {
 255         free_ref_array(&extra_refs);
 256 }
 257
 258 static struct ref_array *get_packed_refs(const char *submodule)
 259 {
 260         struct cached_refs *refs = get_cached_refs(submodule);
 261
 262         if (!refs->did_packed) {
 263                 const char *packed_refs_file;
 264                 FILE *f;
 265
 266                 if (submodule)
 267                         packed_refs_file = git_path_submodule(submodule, "packed-refs");
 268                 else
 269                         packed_refs_file = git_path("packed-refs");
 270                 f = fopen(packed_refs_file, "r");
 271                 if (f) {
 272                         read_packed_refs(f, &refs->packed);
 273                         fclose(f);
 274                 }
 275                 refs->did_packed = 1;
 276         }
 277         return &refs->packed;
 278 }
 279
 280 static void get_ref_dir(const char *submodule, const char *base,
 281                         struct ref_array *array)
 282 {
 283         DIR *dir;
 284         const char *path;
 285
 286         if (submodule)
 287                 path = git_path_submodule(submodule, "%s", base);
 288         else
 289                 path = git_path("%s", base);
 290
 291
 292         dir = opendir(path);
 293
 294         if (dir) {
 295                 struct dirent *de;
 296                 int baselen = strlen(base);
 297                 char *ref = xmalloc(baselen + 257);
 298
 299                 memcpy(ref, base, baselen);
 300                 if (baselen && base[baselen-1] != '/')
 301                         ref[baselen++] = '/';
 302
 303                 while ((de = readdir(dir)) != NULL) {
 304                         unsigned char sha1[20];
 305                         struct stat st;
 306                         int flag;
 307                         int namelen;
 308                         const char *refdir;
 309
 310                         if (de->d_name[0] == '.')
 311                                 continue;
 312                         namelen = strlen(de->d_name);
 313                         if (namelen > 255)
 314                                 continue;
 315                         if (has_extension(de->d_name, ".lock"))
 316                                 continue;
 317                         memcpy(ref + baselen, de->d_name, namelen+1);
 318                         refdir = submodule
 319                                 ? git_path_submodule(submodule, "%s", ref)
 320                                 : git_path("%s", ref);
 321                         if (stat(refdir, &st) < 0)
 322                                 continue;
 323                         if (S_ISDIR(st.st_mode)) {
 324                                 get_ref_dir(submodule, ref, array);
 325                                 continue;
 326                         }
 327                         if (submodule) {
 328                                 hashclr(sha1);
 329                                 flag = 0;
 330                                 if (resolve_gitlink_ref(submodule, ref, sha1) < 0) {
 331                                         hashclr(sha1);
 332                                         flag |= REF_BROKEN;
 333                                 }
 334                         } else
 335                                 if (!resolve_ref(ref, sha1, 1, &flag)) {
 336                                         hashclr(sha1);
 337                                         flag |= REF_BROKEN;
 338                                 }
 339                         add_ref(ref, sha1, flag, array, NULL);
 340                 }
 341                 free(ref);
 342                 closedir(dir);
 343         }
 344 }
 345
 346 struct warn_if_dangling_data {
 347         FILE *fp;
 348         const char *refname;
 349         const char *msg_fmt;
 350 };
 351
 352 static int warn_if_dangling_symref(const char *refname, const unsigned char *sha1,
 353                                    int flags, void *cb_data)
 354 {
 355         struct warn_if_dangling_data *d = cb_data;
 356         const char *resolves_to;
 357         unsigned char junk[20];
 358
 359         if (!(flags & REF_ISSYMREF))
 360                 return 0;
 361
 362         resolves_to = resolve_ref(refname, junk, 0, NULL);
 363         if (!resolves_to || strcmp(resolves_to, d->refname))
 364                 return 0;
 365
 366         fprintf(d->fp, d->msg_fmt, refname);
 367         return 0;
 368 }
 369
 370 void warn_dangling_symref(FILE *fp, const char *msg_fmt, const char *refname)
 371 {
 372         struct warn_if_dangling_data data;
 373
 374         data.fp = fp;
 375         data.refname = refname;
 376         data.msg_fmt = msg_fmt;
 377         for_each_rawref(warn_if_dangling_symref, &data);
 378 }
 379
 380 static struct ref_array *get_loose_refs(const char *submodule)
 381 {
 382         struct cached_refs *refs = get_cached_refs(submodule);
 383
 384         if (!refs->did_loose) {
 385                 get_ref_dir(submodule, "refs", &refs->loose);
 386                 sort_ref_array(&refs->loose);
 387                 refs->did_loose = 1;
 388         }
 389         return &refs->loose;
 390 }
 391
 392 /* We allow "recursive" symbolic refs. Only within reason, though */
 393 #define MAXDEPTH 5
 394 #define MAXREFLEN (1024)
 395
 396 /*
 397  * Called by resolve_gitlink_ref_recursive() after it failed to read
 398  * from "name", which is "module/.git/<refname>". Find <refname> in
 399  * the packed-refs file for the submodule.
 400  */
 401 static int resolve_gitlink_packed_ref(char *name, int pathlen, const char *refname, unsigned char *result)
 402 {
 403         int retval = -1;
 404         struct ref_entry *ref;
 405         struct ref_array *array;
 406
 407         /* being defensive: resolve_gitlink_ref() did this for us */
 408         if (pathlen < 6 || memcmp(name + pathlen - 6, "/.git/", 6))
 409                 die("Oops");
 410         name[pathlen - 6] = '\0'; /* make it path to the submodule */
 411         array = get_packed_refs(name);
 412         ref = search_ref_array(array, refname);
 413         if (ref != NULL) {
 414                 memcpy(result, ref->sha1, 20);
 415                 retval = 0;
 416         }
 417         return retval;
 418 }
 419
 420 static int resolve_gitlink_ref_recursive(char *name, int pathlen, const char *refname, unsigned char *result, int recursion)
 421 {
 422         int fd, len = strlen(refname);
 423         char buffer[128], *p;
 424
 425         if (recursion > MAXDEPTH || len > MAXREFLEN)
 426                 return -1;
 427         memcpy(name + pathlen, refname, len+1);
 428         fd = open(name, O_RDONLY);
 429         if (fd < 0)
 430                 return resolve_gitlink_packed_ref(name, pathlen, refname, result);
 431
 432         len = read(fd, buffer, sizeof(buffer)-1);
 433         close(fd);
 434         if (len < 0)
 435                 return -1;
 436         while (len && isspace(buffer[len-1]))
 437                 len--;
 438         buffer[len] = 0;
 439
 440         /* Was it a detached head or an old-fashioned symlink? */
 441         if (!get_sha1_hex(buffer, result))
 442                 return 0;
 443
 444         /* Symref? */
 445         if (strncmp(buffer, "ref:", 4))
 446                 return -1;
 447         p = buffer + 4;
 448         while (isspace(*p))
 449                 p++;
 450
 451         return resolve_gitlink_ref_recursive(name, pathlen, p, result, recursion+1);
 452 }
 453
 454 int resolve_gitlink_ref(const char *path, const char *refname, unsigned char *result)
 455 {
 456         int len = strlen(path), retval;
 457         char *gitdir;
 458         const char *tmp;
 459
 460         while (len && path[len-1] == '/')
 461                 len--;
 462         if (!len)
 463                 return -1;
 464         gitdir = xmalloc(len + MAXREFLEN + 8);
 465         memcpy(gitdir, path, len);
 466         memcpy(gitdir + len, "/.git", 6);
 467         len += 5;
 468
 469         tmp = read_gitfile(gitdir);
 470         if (tmp) {
 471                 free(gitdir);
 472                 len = strlen(tmp);
 473                 gitdir = xmalloc(len + MAXREFLEN + 3);
 474                 memcpy(gitdir, tmp, len);
 475         }
 476         gitdir[len] = '/';
 477         gitdir[++len] = '\0';
 478         retval = resolve_gitlink_ref_recursive(gitdir, len, refname, result, 0);
 479         free(gitdir);
 480         return retval;
 481 }
 482
 483 /*
 484  * Try to read ref from the packed references.  On success, set sha1
 485  * and return 0; otherwise, return -1.
 486  */
 487 static int get_packed_ref(const char *ref, unsigned char *sha1)
 488 {
 489         struct ref_array *packed = get_packed_refs(NULL);
 490         struct ref_entry *entry = search_ref_array(packed, ref);
 491         if (entry) {
 492                 hashcpy(sha1, entry->sha1);
 493                 return 0;
 494         }
 495         return -1;
 496 }
 497
 498 const char *resolve_ref(const char *ref, unsigned char *sha1, int reading, int *flag)
 499 {
 500         int depth = MAXDEPTH;
 501         ssize_t len;
 502         char buffer[256];
 503         static char ref_buffer[256];
 504         char path[PATH_MAX];
 505
 506         if (flag)
 507                 *flag = 0;
 508
 509         if (check_refname_format(ref, REFNAME_ALLOW_ONELEVEL))
 510                 return NULL;
 511
 512         for (;;) {
 513                 struct stat st;
 514                 char *buf;
 515                 int fd;
 516
 517                 if (--depth < 0)
 518                         return NULL;
 519
 520                 git_snpath(path, sizeof(path), "%s", ref);
 521
 522                 if (lstat(path, &st) < 0) {
 523                         if (errno != ENOENT)
 524                                 return NULL;
 525                         /*
 526                          * The loose reference file does not exist;
 527                          * check for a packed reference.
 528                          */
 529                         if (!get_packed_ref(ref, sha1)) {
 530                                 if (flag)
 531                                         *flag |= REF_ISPACKED;
 532                                 return ref;
 533                         }
 534                         /* The reference is not a packed reference, either. */
 535                         if (reading) {
 536                                 return NULL;
 537                         } else {
 538                                 hashclr(sha1);
 539                                 return ref;
 540                         }
 541                 }
 542
 543                 /* Follow "normalized" - ie "refs/.." symlinks by hand */
 544                 if (S_ISLNK(st.st_mode)) {
 545                         len = readlink(path, buffer, sizeof(buffer)-1);
 546                         if (len < 0)
 547                                 return NULL;
 548                         buffer[len] = 0;
 549                         if (!prefixcmp(buffer, "refs/") &&
 550                                         !check_refname_format(buffer, 0)) {
 551                                 strcpy(ref_buffer, buffer);
 552                                 ref = ref_buffer;
 553                                 if (flag)
 554                                         *flag |= REF_ISSYMREF;
 555                                 continue;
 556                         }
 557                 }
 558
 559                 /* Is it a directory? */
 560                 if (S_ISDIR(st.st_mode)) {
 561                         errno = EISDIR;
 562                         return NULL;
 563                 }
 564
 565                 /*
 566                  * Anything else, just open it and try to use it as
 567                  * a ref
 568                  */
 569                 fd = open(path, O_RDONLY);
 570                 if (fd < 0)
 571                         return NULL;
 572                 len = read_in_full(fd, buffer, sizeof(buffer)-1);
 573                 close(fd);
 574                 if (len < 0)
 575                         return NULL;
 576                 while (len && isspace(buffer[len-1]))
 577                         len--;
 578                 buffer[len] = '\0';
 579
 580                 /*
 581                  * Is it a symbolic ref?
 582                  */
 583                 if (prefixcmp(buffer, "ref:"))
 584                         break;
 585                 buf = buffer + 4;
 586                 while (isspace(*buf))
 587                         buf++;
 588                 if (check_refname_format(buf, REFNAME_ALLOW_ONELEVEL)) {
 589                         warning("symbolic reference in %s is formatted incorrectly",
 590                                 path);
 591                         return NULL;
 592                 }
 593                 ref = strcpy(ref_buffer, buf);
 594                 if (flag)
 595                         *flag |= REF_ISSYMREF;
 596         }
 597         /* Please note that FETCH_HEAD has a second line containing other data. */
 598         if (get_sha1_hex(buffer, sha1) || (buffer[40] != '\0' && !isspace(buffer[40]))) {
 599                 warning("reference in %s is formatted incorrectly", path);
 600                 return NULL;
 601         }
 602         return ref;
 603 }
 604
 605 /* The argument to filter_refs */
 606 struct ref_filter {
 607         const char *pattern;
 608         each_ref_fn *fn;
 609         void *cb_data;
 610 };
 611
 612 int read_ref(const char *ref, unsigned char *sha1)
 613 {
 614         if (resolve_ref(ref, sha1, 1, NULL))
 615                 return 0;
 616         return -1;
 617 }
 618
 619 #define DO_FOR_EACH_INCLUDE_BROKEN 01
 620 static int do_one_ref(const char *base, each_ref_fn fn, int trim,
 621                       int flags, void *cb_data, struct ref_entry *entry)
 622 {
 623         if (prefixcmp(entry->name, base))
 624                 return 0;
 625
 626         if (!(flags & DO_FOR_EACH_INCLUDE_BROKEN)) {
 627                 if (entry->flag & REF_BROKEN)
 628                         return 0; /* ignore dangling symref */
 629                 if (!has_sha1_file(entry->sha1)) {
 630                         error("%s does not point to a valid object!", entry->name);
 631                         return 0;
 632                 }
 633         }
 634         current_ref = entry;
 635         return fn(entry->name + trim, entry->sha1, entry->flag, cb_data);
 636 }
 637
 638 static int filter_refs(const char *ref, const unsigned char *sha, int flags,
 639         void *data)
 640 {
 641         struct ref_filter *filter = (struct ref_filter *)data;
 642         if (fnmatch(filter->pattern, ref, 0))
 643                 return 0;
 644         return filter->fn(ref, sha, flags, filter->cb_data);
 645 }
 646
 647 int peel_ref(const char *ref, unsigned char *sha1)
 648 {
 649         int flag;
 650         unsigned char base[20];
 651         struct object *o;
 652
 653         if (current_ref && (current_ref->name == ref
 654                 || !strcmp(current_ref->name, ref))) {
 655                 if (current_ref->flag & REF_KNOWS_PEELED) {
 656                         hashcpy(sha1, current_ref->peeled);
 657                         return 0;
 658                 }
 659                 hashcpy(base, current_ref->sha1);
 660                 goto fallback;
 661         }
 662
 663         if (!resolve_ref(ref, base, 1, &flag))
 664                 return -1;
 665
 666         if ((flag & REF_ISPACKED)) {
 667                 struct ref_array *array = get_packed_refs(NULL);
 668                 struct ref_entry *r = search_ref_array(array, ref);
 669
 670                 if (r != NULL && r->flag & REF_KNOWS_PEELED) {
 671                         hashcpy(sha1, r->peeled);
 672                         return 0;
 673                 }
 674         }
 675
 676 fallback:
 677         o = parse_object(base);
 678         if (o && o->type == OBJ_TAG) {
 679                 o = deref_tag(o, ref, 0);
 680                 if (o) {
 681                         hashcpy(sha1, o->sha1);
 682                         return 0;
 683                 }
 684         }
 685         return -1;
 686 }
 687
 688 static int do_for_each_ref(const char *submodule, const char *base, each_ref_fn fn,
 689                            int trim, int flags, void *cb_data)
 690 {
 691         int retval = 0, i, p = 0, l = 0;
 692         struct ref_array *packed = get_packed_refs(submodule);
 693         struct ref_array *loose = get_loose_refs(submodule);
 694
 695         struct ref_array *extra = &extra_refs;
 696
 697         for (i = 0; i < extra->nr; i++)
 698                 retval = do_one_ref(base, fn, trim, flags, cb_data, extra->refs[i]);
 699
 700         while (p < packed->nr && l < loose->nr) {
 701                 struct ref_entry *entry;
 702                 int cmp = strcmp(packed->refs[p]->name, loose->refs[l]->name);
 703                 if (!cmp) {
 704                         p++;
 705                         continue;
 706                 }
 707                 if (cmp > 0) {
 708                         entry = loose->refs[l++];
 709                 } else {
 710                         entry = packed->refs[p++];
 711                 }
 712                 retval = do_one_ref(base, fn, trim, flags, cb_data, entry);
 713                 if (retval)
 714                         goto end_each;
 715         }
 716
 717         if (l < loose->nr) {
 718                 p = l;
 719                 packed = loose;
 720         }
 721
 722         for (; p < packed->nr; p++) {
 723                 retval = do_one_ref(base, fn, trim, flags, cb_data, packed->refs[p]);
 724                 if (retval)
 725                         goto end_each;
 726         }
 727
 728 end_each:
 729         current_ref = NULL;
 730         return retval;
 731 }
 732
 733
 734 static int do_head_ref(const char *submodule, each_ref_fn fn, void *cb_data)
 735 {
 736         unsigned char sha1[20];
 737         int flag;
 738
 739         if (submodule) {
 740                 if (resolve_gitlink_ref(submodule, "HEAD", sha1) == 0)
 741                         return fn("HEAD", sha1, 0, cb_data);
 742
 743                 return 0;
 744         }
 745
 746         if (resolve_ref("HEAD", sha1, 1, &flag))
 747                 return fn("HEAD", sha1, flag, cb_data);
 748
 749         return 0;
 750 }
 751
 752 int head_ref(each_ref_fn fn, void *cb_data)
 753 {
 754         return do_head_ref(NULL, fn, cb_data);
 755 }
 756
 757 int head_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
 758 {
 759         return do_head_ref(submodule, fn, cb_data);
 760 }
 761
 762 int for_each_ref(each_ref_fn fn, void *cb_data)
 763 {
 764         return do_for_each_ref(NULL, "", fn, 0, 0, cb_data);
 765 }
 766
 767 int for_each_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
 768 {
 769         return do_for_each_ref(submodule, "", fn, 0, 0, cb_data);
 770 }
 771
 772 int for_each_ref_in(const char *prefix, each_ref_fn fn, void *cb_data)
 773 {
 774         return do_for_each_ref(NULL, prefix, fn, strlen(prefix), 0, cb_data);
 775 }
 776
 777 int for_each_ref_in_submodule(const char *submodule, const char *prefix,
 778                 each_ref_fn fn, void *cb_data)
 779 {
 780         return do_for_each_ref(submodule, prefix, fn, strlen(prefix), 0, cb_data);
 781 }
 782
 783 int for_each_tag_ref(each_ref_fn fn, void *cb_data)
 784 {
 785         return for_each_ref_in("refs/tags/", fn, cb_data);
 786 }
 787
 788 int for_each_tag_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
 789 {
 790         return for_each_ref_in_submodule(submodule, "refs/tags/", fn, cb_data);
 791 }
 792
 793 int for_each_branch_ref(each_ref_fn fn, void *cb_data)
 794 {
 795         return for_each_ref_in("refs/heads/", fn, cb_data);
 796 }
 797
 798 int for_each_branch_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
 799 {
 800         return for_each_ref_in_submodule(submodule, "refs/heads/", fn, cb_data);
 801 }
 802
 803 int for_each_remote_ref(each_ref_fn fn, void *cb_data)
 804 {
 805         return for_each_ref_in("refs/remotes/", fn, cb_data);
 806 }
 807
 808 int for_each_remote_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
 809 {
 810         return for_each_ref_in_submodule(submodule, "refs/remotes/", fn, cb_data);
 811 }
 812
 813 int for_each_replace_ref(each_ref_fn fn, void *cb_data)
 814 {
 815         return do_for_each_ref(NULL, "refs/replace/", fn, 13, 0, cb_data);
 816 }
 817
 818 int head_ref_namespaced(each_ref_fn fn, void *cb_data)
 819 {
 820         struct strbuf buf = STRBUF_INIT;
 821         int ret = 0;
 822         unsigned char sha1[20];
 823         int flag;
 824
 825         strbuf_addf(&buf, "%sHEAD", get_git_namespace());
 826         if (resolve_ref(buf.buf, sha1, 1, &flag))
 827                 ret = fn(buf.buf, sha1, flag, cb_data);
 828         strbuf_release(&buf);
 829
 830         return ret;
 831 }
 832
 833 int for_each_namespaced_ref(each_ref_fn fn, void *cb_data)
 834 {
 835         struct strbuf buf = STRBUF_INIT;
 836         int ret;
 837         strbuf_addf(&buf, "%srefs/", get_git_namespace());
 838         ret = do_for_each_ref(NULL, buf.buf, fn, 0, 0, cb_data);
 839         strbuf_release(&buf);
 840         return ret;
 841 }
 842
 843 int for_each_glob_ref_in(each_ref_fn fn, const char *pattern,
 844         const char *prefix, void *cb_data)
 845 {
 846         struct strbuf real_pattern = STRBUF_INIT;
 847         struct ref_filter filter;
 848         int ret;
 849
 850         if (!prefix && prefixcmp(pattern, "refs/"))
 851                 strbuf_addstr(&real_pattern, "refs/");
 852         else if (prefix)
 853                 strbuf_addstr(&real_pattern, prefix);
 854         strbuf_addstr(&real_pattern, pattern);
 855
 856         if (!has_glob_specials(pattern)) {
 857                 /* Append implied '/' '*' if not present. */
 858                 if (real_pattern.buf[real_pattern.len - 1] != '/')
 859                         strbuf_addch(&real_pattern, '/');
 860                 /* No need to check for '*', there is none. */
 861                 strbuf_addch(&real_pattern, '*');
 862         }
 863
 864         filter.pattern = real_pattern.buf;
 865         filter.fn = fn;
 866         filter.cb_data = cb_data;
 867         ret = for_each_ref(filter_refs, &filter);
 868
 869         strbuf_release(&real_pattern);
 870         return ret;
 871 }
 872
 873 int for_each_glob_ref(each_ref_fn fn, const char *pattern, void *cb_data)
 874 {
 875         return for_each_glob_ref_in(fn, pattern, NULL, cb_data);
 876 }
 877
 878 int for_each_rawref(each_ref_fn fn, void *cb_data)
 879 {
 880         return do_for_each_ref(NULL, "", fn, 0,
 881                                DO_FOR_EACH_INCLUDE_BROKEN, cb_data);
 882 }
 883
 884 /*
 885  * Make sure "ref" is something reasonable to have under ".git/refs/";
 886  * We do not like it if:
 887  *
 888  * - any path component of it begins with ".", or
 889  * - it has double dots "..", or
 890  * - it has ASCII control character, "~", "^", ":" or SP, anywhere, or
 891  * - it ends with a "/".
 892  * - it ends with ".lock"
 893  * - it contains a "\" (backslash)
 894  */
 895
 896 /* Return true iff ch is not allowed in reference names. */
 897 static inline int bad_ref_char(int ch)
 898 {
 899         if (((unsigned) ch) <= ' ' || ch == 0x7f ||
 900             ch == '~' || ch == '^' || ch == ':' || ch == '\\')
 901                 return 1;
 902         /* 2.13 Pattern Matching Notation */
 903         if (ch == '*' || ch == '?' || ch == '[') /* Unsupported */
 904                 return 1;
 905         return 0;
 906 }
 907
 908 /*
 909  * Try to read one refname component from the front of ref.  Return
 910  * the length of the component found, or -1 if the component is not
 911  * legal.
 912  */
 913 static int check_refname_component(const char *ref, int flags)
 914 {
 915         const char *cp;
 916         char last = '\0';
 917
 918         for (cp = ref; ; cp++) {
 919                 char ch = *cp;
 920                 if (ch == '\0' || ch == '/')
 921                         break;
 922                 if (bad_ref_char(ch))
 923                         return -1; /* Illegal character in refname. */
 924                 if (last == '.' && ch == '.')
 925                         return -1; /* Refname contains "..". */
 926                 if (last == '@' && ch == '{')
 927                         return -1; /* Refname contains "@{". */
 928                 last = ch;
 929         }
 930         if (cp == ref)
 931                 return -1; /* Component has zero length. */
 932         if (ref[0] == '.') {
 933                 if (!(flags & REFNAME_DOT_COMPONENT))
 934                         return -1; /* Component starts with '.'. */
 935                 /*
 936                  * Even if leading dots are allowed, don't allow "."
 937                  * as a component (".." is prevented by a rule above).
 938                  */
 939                 if (ref[1] == '\0')
 940                         return -1; /* Component equals ".". */
 941         }
 942         if (cp - ref >= 5 && !memcmp(cp - 5, ".lock", 5))
 943                 return -1; /* Refname ends with ".lock". */
 944         return cp - ref;
 945 }
 946
 947 int check_refname_format(const char *ref, int flags)
 948 {
 949         int component_len, component_count = 0;
 950
 951         while (1) {
 952                 /* We are at the start of a path component. */
 953                 component_len = check_refname_component(ref, flags);
 954                 if (component_len < 0) {
 955                         if ((flags & REFNAME_REFSPEC_PATTERN) &&
 956                                         ref[0] == '*' &&
 957                                         (ref[1] == '\0' || ref[1] == '/')) {
 958                                 /* Accept one wildcard as a full refname component. */
 959                                 flags &= ~REFNAME_REFSPEC_PATTERN;
 960                                 component_len = 1;
 961                         } else {
 962                                 return -1;
 963                         }
 964                 }
 965                 component_count++;
 966                 if (ref[component_len] == '\0')
 967                         break;
 968                 /* Skip to next component. */
 969                 ref += component_len + 1;
 970         }
 971
 972         if (ref[component_len - 1] == '.')
 973                 return -1; /* Refname ends with '.'. */
 974         if (!(flags & REFNAME_ALLOW_ONELEVEL) && component_count < 2)
 975                 return -1; /* Refname has only one component. */
 976         return 0;
 977 }
 978
 979 const char *prettify_refname(const char *name)
 980 {
 981         return name + (
 982                 !prefixcmp(name, "refs/heads/") ? 11 :
 983                 !prefixcmp(name, "refs/tags/") ? 10 :
 984                 !prefixcmp(name, "refs/remotes/") ? 13 :
 985                 0);
 986 }
 987
 988 const char *ref_rev_parse_rules[] = {
 989         "%.*s",
 990         "refs/%.*s",
 991         "refs/tags/%.*s",
 992         "refs/heads/%.*s",
 993         "refs/remotes/%.*s",
 994         "refs/remotes/%.*s/HEAD",
 995         NULL
 996 };
 997
 998 const char *ref_fetch_rules[] = {
 999         "%.*s",
1000         "refs/%.*s",
1001         "refs/tags/%.*s",
1002         "refs/heads/%.*s",
1003         NULL
1004 };
1005
1006 int refname_match(const char *abbrev_name, const char *full_name, const char **rules)
1007 {
1008         const char **p;
1009         const int abbrev_name_len = strlen(abbrev_name);
1010
1011         for (p = rules; *p; p++) {
1012                 if (!strcmp(full_name, mkpath(*p, abbrev_name_len, abbrev_name))) {
1013                         return 1;
1014                 }
1015         }
1016
1017         return 0;
1018 }
1019
1020 static struct ref_lock *verify_lock(struct ref_lock *lock,
1021         const unsigned char *old_sha1, int mustexist)
1022 {
1023         if (!resolve_ref(lock->ref_name, lock->old_sha1, mustexist, NULL)) {
1024                 error("Can't verify ref %s", lock->ref_name);
1025                 unlock_ref(lock);
1026                 return NULL;
1027         }
1028         if (hashcmp(lock->old_sha1, old_sha1)) {
1029                 error("Ref %s is at %s but expected %s", lock->ref_name,
1030                         sha1_to_hex(lock->old_sha1), sha1_to_hex(old_sha1));
1031                 unlock_ref(lock);
1032                 return NULL;
1033         }
1034         return lock;
1035 }
1036
1037 static int remove_empty_directories(const char *file)
1038 {
1039         /* we want to create a file but there is a directory there;
1040          * if that is an empty directory (or a directory that contains
1041          * only empty directories), remove them.
1042          */
1043         struct strbuf path;
1044         int result;
1045
1046         strbuf_init(&path, 20);
1047         strbuf_addstr(&path, file);
1048
1049         result = remove_dir_recursively(&path, REMOVE_DIR_EMPTY_ONLY);
1050
1051         strbuf_release(&path);
1052
1053         return result;
1054 }
1055
1056 static int is_refname_available(const char *ref, const char *oldref,
1057                                 struct ref_array *array, int quiet)
1058 {
1059         int i, namlen = strlen(ref); /* e.g. 'foo/bar' */
1060         for (i = 0; i < array->nr; i++ ) {
1061                 struct ref_entry *entry = array->refs[i];
1062                 /* entry->name could be 'foo' or 'foo/bar/baz' */
1063                 if (!oldref || strcmp(oldref, entry->name)) {
1064                         int len = strlen(entry->name);
1065                         int cmplen = (namlen < len) ? namlen : len;
1066                         const char *lead = (namlen < len) ? entry->name : ref;
1067                         if (!strncmp(ref, entry->name, cmplen) &&
1068                             lead[cmplen] == '/') {
1069                                 if (!quiet)
1070                                         error("'%s' exists; cannot create '%s'",
1071                                               entry->name, ref);
1072                                 return 0;
1073                         }
1074                 }
1075         }
1076         return 1;
1077 }
1078
1079 static struct ref_lock *lock_ref_sha1_basic(const char *ref, const unsigned char *old_sha1, int flags, int *type_p)
1080 {
1081         char *ref_file;
1082         const char *orig_ref = ref;
1083         struct ref_lock *lock;
1084         int last_errno = 0;
1085         int type, lflags;
1086         int mustexist = (old_sha1 && !is_null_sha1(old_sha1));
1087         int missing = 0;
1088
1089         lock = xcalloc(1, sizeof(struct ref_lock));
1090         lock->lock_fd = -1;
1091
1092         ref = resolve_ref(ref, lock->old_sha1, mustexist, &type);
1093         if (!ref && errno == EISDIR) {
1094                 /* we are trying to lock foo but we used to
1095                  * have foo/bar which now does not exist;
1096                  * it is normal for the empty directory 'foo'
1097                  * to remain.
1098                  */
1099                 ref_file = git_path("%s", orig_ref);
1100                 if (remove_empty_directories(ref_file)) {
1101                         last_errno = errno;
1102                         error("there are still refs under '%s'", orig_ref);
1103                         goto error_return;
1104                 }
1105                 ref = resolve_ref(orig_ref, lock->old_sha1, mustexist, &type);
1106         }
1107         if (type_p)
1108             *type_p = type;
1109         if (!ref) {
1110                 last_errno = errno;
1111                 error("unable to resolve reference %s: %s",
1112                         orig_ref, strerror(errno));
1113                 goto error_return;
1114         }
1115         missing = is_null_sha1(lock->old_sha1);
1116         /* When the ref did not exist and we are creating it,
1117          * make sure there is no existing ref that is packed
1118          * whose name begins with our refname, nor a ref whose
1119          * name is a proper prefix of our refname.
1120          */
1121         if (missing &&
1122              !is_refname_available(ref, NULL, get_packed_refs(NULL), 0)) {
1123                 last_errno = ENOTDIR;
1124                 goto error_return;
1125         }
1126
1127         lock->lk = xcalloc(1, sizeof(struct lock_file));
1128
1129         lflags = LOCK_DIE_ON_ERROR;
1130         if (flags & REF_NODEREF) {
1131                 ref = orig_ref;
1132                 lflags |= LOCK_NODEREF;
1133         }
1134         lock->ref_name = xstrdup(ref);
1135         lock->orig_ref_name = xstrdup(orig_ref);
1136         ref_file = git_path("%s", ref);
1137         if (missing)
1138                 lock->force_write = 1;
1139         if ((flags & REF_NODEREF) && (type & REF_ISSYMREF))
1140                 lock->force_write = 1;
1141
1142         if (safe_create_leading_directories(ref_file)) {
1143                 last_errno = errno;
1144                 error("unable to create directory for %s", ref_file);
1145                 goto error_return;
1146         }
1147
1148         lock->lock_fd = hold_lock_file_for_update(lock->lk, ref_file, lflags);
1149         return old_sha1 ? verify_lock(lock, old_sha1, mustexist) : lock;
1150
1151  error_return:
1152         unlock_ref(lock);
1153         errno = last_errno;
1154         return NULL;
1155 }
1156
1157 struct ref_lock *lock_ref_sha1(const char *ref, const unsigned char *old_sha1)
1158 {
1159         char refpath[PATH_MAX];
1160         if (check_refname_format(ref, 0))
1161                 return NULL;
1162         strcpy(refpath, mkpath("refs/%s", ref));
1163         return lock_ref_sha1_basic(refpath, old_sha1, 0, NULL);
1164 }
1165
1166 struct ref_lock *lock_any_ref_for_update(const char *ref, const unsigned char *old_sha1, int flags)
1167 {
1168         if (check_refname_format(ref, REFNAME_ALLOW_ONELEVEL))
1169                 return NULL;
1170         return lock_ref_sha1_basic(ref, old_sha1, flags, NULL);
1171 }
1172
1173 static struct lock_file packlock;
1174
1175 static int repack_without_ref(const char *refname)
1176 {
1177         struct ref_array *packed;
1178         struct ref_entry *ref;
1179         int fd, i;
1180
1181         packed = get_packed_refs(NULL);
1182         ref = search_ref_array(packed, refname);
1183         if (ref == NULL)
1184                 return 0;
1185         fd = hold_lock_file_for_update(&packlock, git_path("packed-refs"), 0);
1186         if (fd < 0) {
1187                 unable_to_lock_error(git_path("packed-refs"), errno);
1188                 return error("cannot delete '%s' from packed refs", refname);
1189         }
1190
1191         for (i = 0; i < packed->nr; i++) {
1192                 char line[PATH_MAX + 100];
1193                 int len;
1194
1195                 ref = packed->refs[i];
1196
1197                 if (!strcmp(refname, ref->name))
1198                         continue;
1199                 len = snprintf(line, sizeof(line), "%s %s\n",
1200                                sha1_to_hex(ref->sha1), ref->name);
1201                 /* this should not happen but just being defensive */
1202                 if (len > sizeof(line))
1203                         die("too long a refname '%s'", ref->name);
1204                 write_or_die(fd, line, len);
1205         }
1206         return commit_lock_file(&packlock);
1207 }
1208
1209 int delete_ref(const char *refname, const unsigned char *sha1, int delopt)
1210 {
1211         struct ref_lock *lock;
1212         int err, i = 0, ret = 0, flag = 0;
1213
1214         lock = lock_ref_sha1_basic(refname, sha1, 0, &flag);
1215         if (!lock)
1216                 return 1;
1217         if (!(flag & REF_ISPACKED) || flag & REF_ISSYMREF) {
1218                 /* loose */
1219                 const char *path;
1220
1221                 if (!(delopt & REF_NODEREF)) {
1222                         i = strlen(lock->lk->filename) - 5; /* .lock */
1223                         lock->lk->filename[i] = 0;
1224                         path = lock->lk->filename;
1225                 } else {
1226                         path = git_path("%s", refname);
1227                 }
1228                 err = unlink_or_warn(path);
1229                 if (err && errno != ENOENT)
1230                         ret = 1;
1231
1232                 if (!(delopt & REF_NODEREF))
1233                         lock->lk->filename[i] = '.';
1234         }
1235         /* removing the loose one could have resurrected an earlier
1236          * packed one.  Also, if it was not loose we need to repack
1237          * without it.
1238          */
1239         ret |= repack_without_ref(refname);
1240
1241         unlink_or_warn(git_path("logs/%s", lock->ref_name));
1242         invalidate_cached_refs();
1243         unlock_ref(lock);
1244         return ret;
1245 }
1246
1247 /*
1248  * People using contrib's git-new-workdir have .git/logs/refs ->
1249  * /some/other/path/.git/logs/refs, and that may live on another device.
1250  *
1251  * IOW, to avoid cross device rename errors, the temporary renamed log must
1252  * live into logs/refs.
1253  */
1254 #define TMP_RENAMED_LOG  "logs/refs/.tmp-renamed-log"
1255
1256 int rename_ref(const char *oldref, const char *newref, const char *logmsg)
1257 {
1258         static const char renamed_ref[] = "RENAMED-REF";
1259         unsigned char sha1[20], orig_sha1[20];
1260         int flag = 0, logmoved = 0;
1261         struct ref_lock *lock;
1262         struct stat loginfo;
1263         int log = !lstat(git_path("logs/%s", oldref), &loginfo);
1264         const char *symref = NULL;
1265
1266         if (log && S_ISLNK(loginfo.st_mode))
1267                 return error("reflog for %s is a symlink", oldref);
1268
1269         symref = resolve_ref(oldref, orig_sha1, 1, &flag);
1270         if (flag & REF_ISSYMREF)
1271                 return error("refname %s is a symbolic ref, renaming it is not supported",
1272                         oldref);
1273         if (!symref)
1274                 return error("refname %s not found", oldref);
1275
1276         if (!is_refname_available(newref, oldref, get_packed_refs(NULL), 0))
1277                 return 1;
1278
1279         if (!is_refname_available(newref, oldref, get_loose_refs(NULL), 0))
1280                 return 1;
1281
1282         lock = lock_ref_sha1_basic(renamed_ref, NULL, 0, NULL);
1283         if (!lock)
1284                 return error("unable to lock %s", renamed_ref);
1285         lock->force_write = 1;
1286         if (write_ref_sha1(lock, orig_sha1, logmsg))
1287                 return error("unable to save current sha1 in %s", renamed_ref);
1288
1289         if (log && rename(git_path("logs/%s", oldref), git_path(TMP_RENAMED_LOG)))
1290                 return error("unable to move logfile logs/%s to "TMP_RENAMED_LOG": %s",
1291                         oldref, strerror(errno));
1292
1293         if (delete_ref(oldref, orig_sha1, REF_NODEREF)) {
1294                 error("unable to delete old %s", oldref);
1295                 goto rollback;
1296         }
1297
1298         if (resolve_ref(newref, sha1, 1, &flag) && delete_ref(newref, sha1, REF_NODEREF)) {
1299                 if (errno==EISDIR) {
1300                         if (remove_empty_directories(git_path("%s", newref))) {
1301                                 error("Directory not empty: %s", newref);
1302                                 goto rollback;
1303                         }
1304                 } else {
1305                         error("unable to delete existing %s", newref);
1306                         goto rollback;
1307                 }
1308         }
1309
1310         if (log && safe_create_leading_directories(git_path("logs/%s", newref))) {
1311                 error("unable to create directory for %s", newref);
1312                 goto rollback;
1313         }
1314
1315  retry:
1316         if (log && rename(git_path(TMP_RENAMED_LOG), git_path("logs/%s", newref))) {
1317                 if (errno==EISDIR || errno==ENOTDIR) {
1318                         /*
1319                          * rename(a, b) when b is an existing
1320                          * directory ought to result in ISDIR, but
1321                          * Solaris 5.8 gives ENOTDIR.  Sheesh.
1322                          */
1323                         if (remove_empty_directories(git_path("logs/%s", newref))) {
1324                                 error("Directory not empty: logs/%s", newref);
1325                                 goto rollback;
1326                         }
1327                         goto retry;
1328                 } else {
1329                         error("unable to move logfile "TMP_RENAMED_LOG" to logs/%s: %s",
1330                                 newref, strerror(errno));
1331                         goto rollback;
1332                 }
1333         }
1334         logmoved = log;
1335
1336         lock = lock_ref_sha1_basic(newref, NULL, 0, NULL);
1337         if (!lock) {
1338                 error("unable to lock %s for update", newref);
1339                 goto rollback;
1340         }
1341         lock->force_write = 1;
1342         hashcpy(lock->old_sha1, orig_sha1);
1343         if (write_ref_sha1(lock, orig_sha1, logmsg)) {
1344                 error("unable to write current sha1 into %s", newref);
1345                 goto rollback;
1346         }
1347
1348         return 0;
1349
1350  rollback:
1351         lock = lock_ref_sha1_basic(oldref, NULL, 0, NULL);
1352         if (!lock) {
1353                 error("unable to lock %s for rollback", oldref);
1354                 goto rollbacklog;
1355         }
1356
1357         lock->force_write = 1;
1358         flag = log_all_ref_updates;
1359         log_all_ref_updates = 0;
1360         if (write_ref_sha1(lock, orig_sha1, NULL))
1361                 error("unable to write current sha1 into %s", oldref);
1362         log_all_ref_updates = flag;
1363
1364  rollbacklog:
1365         if (logmoved && rename(git_path("logs/%s", newref), git_path("logs/%s", oldref)))
1366                 error("unable to restore logfile %s from %s: %s",
1367                         oldref, newref, strerror(errno));
1368         if (!logmoved && log &&
1369             rename(git_path(TMP_RENAMED_LOG), git_path("logs/%s", oldref)))
1370                 error("unable to restore logfile %s from "TMP_RENAMED_LOG": %s",
1371                         oldref, strerror(errno));
1372
1373         return 1;
1374 }
1375
1376 int close_ref(struct ref_lock *lock)
1377 {
1378         if (close_lock_file(lock->lk))
1379                 return -1;
1380         lock->lock_fd = -1;
1381         return 0;
1382 }
1383
1384 int commit_ref(struct ref_lock *lock)
1385 {
1386         if (commit_lock_file(lock->lk))
1387                 return -1;
1388         lock->lock_fd = -1;
1389         return 0;
1390 }
1391
1392 void unlock_ref(struct ref_lock *lock)
1393 {
1394         /* Do not free lock->lk -- atexit() still looks at them */
1395         if (lock->lk)
1396                 rollback_lock_file(lock->lk);
1397         free(lock->ref_name);
1398         free(lock->orig_ref_name);
1399         free(lock);
1400 }
1401
1402 /*
1403  * copy the reflog message msg to buf, which has been allocated sufficiently
1404  * large, while cleaning up the whitespaces.  Especially, convert LF to space,
1405  * because reflog file is one line per entry.
1406  */
1407 static int copy_msg(char *buf, const char *msg)
1408 {
1409         char *cp = buf;
1410         char c;
1411         int wasspace = 1;
1412
1413         *cp++ = '\t';
1414         while ((c = *msg++)) {
1415                 if (wasspace && isspace(c))
1416                         continue;
1417                 wasspace = isspace(c);
1418                 if (wasspace)
1419                         c = ' ';
1420                 *cp++ = c;
1421         }
1422         while (buf < cp && isspace(cp[-1]))
1423                 cp--;
1424         *cp++ = '\n';
1425         return cp - buf;
1426 }
1427
1428 int log_ref_setup(const char *ref_name, char *logfile, int bufsize)
1429 {
1430         int logfd, oflags = O_APPEND | O_WRONLY;
1431
1432         git_snpath(logfile, bufsize, "logs/%s", ref_name);
1433         if (log_all_ref_updates &&
1434             (!prefixcmp(ref_name, "refs/heads/") ||
1435              !prefixcmp(ref_name, "refs/remotes/") ||
1436              !prefixcmp(ref_name, "refs/notes/") ||
1437              !strcmp(ref_name, "HEAD"))) {
1438                 if (safe_create_leading_directories(logfile) < 0)
1439                         return error("unable to create directory for %s",
1440                                      logfile);
1441                 oflags |= O_CREAT;
1442         }
1443
1444         logfd = open(logfile, oflags, 0666);
1445         if (logfd < 0) {
1446                 if (!(oflags & O_CREAT) && errno == ENOENT)
1447                         return 0;
1448
1449                 if ((oflags & O_CREAT) && errno == EISDIR) {
1450                         if (remove_empty_directories(logfile)) {
1451                                 return error("There are still logs under '%s'",
1452                                              logfile);
1453                         }
1454                         logfd = open(logfile, oflags, 0666);
1455                 }
1456
1457                 if (logfd < 0)
1458                         return error("Unable to append to %s: %s",
1459                                      logfile, strerror(errno));
1460         }
1461
1462         adjust_shared_perm(logfile);
1463         close(logfd);
1464         return 0;
1465 }
1466
1467 static int log_ref_write(const char *ref_name, const unsigned char *old_sha1,
1468                          const unsigned char *new_sha1, const char *msg)
1469 {
1470         int logfd, result, written, oflags = O_APPEND | O_WRONLY;
1471         unsigned maxlen, len;
1472         int msglen;
1473         char log_file[PATH_MAX];
1474         char *logrec;
1475         const char *committer;
1476
1477         if (log_all_ref_updates < 0)
1478                 log_all_ref_updates = !is_bare_repository();
1479
1480         result = log_ref_setup(ref_name, log_file, sizeof(log_file));
1481         if (result)
1482                 return result;
1483
1484         logfd = open(log_file, oflags);
1485         if (logfd < 0)
1486                 return 0;
1487         msglen = msg ? strlen(msg) : 0;
1488         committer = git_committer_info(0);
1489         maxlen = strlen(committer) + msglen + 100;
1490         logrec = xmalloc(maxlen);
1491         len = sprintf(logrec, "%s %s %s\n",
1492                       sha1_to_hex(old_sha1),
1493                       sha1_to_hex(new_sha1),
1494                       committer);
1495         if (msglen)
1496                 len += copy_msg(logrec + len - 1, msg) - 1;
1497         written = len <= maxlen ? write_in_full(logfd, logrec, len) : -1;
1498         free(logrec);
1499         if (close(logfd) != 0 || written != len)
1500                 return error("Unable to append to %s", log_file);
1501         return 0;
1502 }
1503
1504 static int is_branch(const char *refname)
1505 {
1506         return !strcmp(refname, "HEAD") || !prefixcmp(refname, "refs/heads/");
1507 }
1508
1509 int write_ref_sha1(struct ref_lock *lock,
1510         const unsigned char *sha1, const char *logmsg)
1511 {
1512         static char term = '\n';
1513         struct object *o;
1514
1515         if (!lock)
1516                 return -1;
1517         if (!lock->force_write && !hashcmp(lock->old_sha1, sha1)) {
1518                 unlock_ref(lock);
1519                 return 0;
1520         }
1521         o = parse_object(sha1);
1522         if (!o) {
1523                 error("Trying to write ref %s with nonexistent object %s",
1524                         lock->ref_name, sha1_to_hex(sha1));
1525                 unlock_ref(lock);
1526                 return -1;
1527         }
1528         if (o->type != OBJ_COMMIT && is_branch(lock->ref_name)) {
1529                 error("Trying to write non-commit object %s to branch %s",
1530                         sha1_to_hex(sha1), lock->ref_name);
1531                 unlock_ref(lock);
1532                 return -1;
1533         }
1534         if (write_in_full(lock->lock_fd, sha1_to_hex(sha1), 40) != 40 ||
1535             write_in_full(lock->lock_fd, &term, 1) != 1
1536                 || close_ref(lock) < 0) {
1537                 error("Couldn't write %s", lock->lk->filename);
1538                 unlock_ref(lock);
1539                 return -1;
1540         }
1541         invalidate_cached_refs();
1542         if (log_ref_write(lock->ref_name, lock->old_sha1, sha1, logmsg) < 0 ||
1543             (strcmp(lock->ref_name, lock->orig_ref_name) &&
1544              log_ref_write(lock->orig_ref_name, lock->old_sha1, sha1, logmsg) < 0)) {
1545                 unlock_ref(lock);
1546                 return -1;
1547         }
1548         if (strcmp(lock->orig_ref_name, "HEAD") != 0) {
1549                 /*
1550                  * Special hack: If a branch is updated directly and HEAD
1551                  * points to it (may happen on the remote side of a push
1552                  * for example) then logically the HEAD reflog should be
1553                  * updated too.
1554                  * A generic solution implies reverse symref information,
1555                  * but finding all symrefs pointing to the given branch
1556                  * would be rather costly for this rare event (the direct
1557                  * update of a branch) to be worth it.  So let's cheat and
1558                  * check with HEAD only which should cover 99% of all usage
1559                  * scenarios (even 100% of the default ones).
1560                  */
1561                 unsigned char head_sha1[20];
1562                 int head_flag;
1563                 const char *head_ref;
1564                 head_ref = resolve_ref("HEAD", head_sha1, 1, &head_flag);
1565                 if (head_ref && (head_flag & REF_ISSYMREF) &&
1566                     !strcmp(head_ref, lock->ref_name))
1567                         log_ref_write("HEAD", lock->old_sha1, sha1, logmsg);
1568         }
1569         if (commit_ref(lock)) {
1570                 error("Couldn't set %s", lock->ref_name);
1571                 unlock_ref(lock);
1572                 return -1;
1573         }
1574         unlock_ref(lock);
1575         return 0;
1576 }
1577
1578 int create_symref(const char *ref_target, const char *refs_heads_master,
1579                   const char *logmsg)
1580 {
1581         const char *lockpath;
1582         char ref[1000];
1583         int fd, len, written;
1584         char *git_HEAD = git_pathdup("%s", ref_target);
1585         unsigned char old_sha1[20], new_sha1[20];
1586
1587         if (logmsg && read_ref(ref_target, old_sha1))
1588                 hashclr(old_sha1);
1589
1590         if (safe_create_leading_directories(git_HEAD) < 0)
1591                 return error("unable to create directory for %s", git_HEAD);
1592
1593 #ifndef NO_SYMLINK_HEAD
1594         if (prefer_symlink_refs) {
1595                 unlink(git_HEAD);
1596                 if (!symlink(refs_heads_master, git_HEAD))
1597                         goto done;
1598                 fprintf(stderr, "no symlink - falling back to symbolic ref\n");
1599         }
1600 #endif
1601
1602         len = snprintf(ref, sizeof(ref), "ref: %s\n", refs_heads_master);
1603         if (sizeof(ref) <= len) {
1604                 error("refname too long: %s", refs_heads_master);
1605                 goto error_free_return;
1606         }
1607         lockpath = mkpath("%s.lock", git_HEAD);
1608         fd = open(lockpath, O_CREAT | O_EXCL | O_WRONLY, 0666);
1609         if (fd < 0) {
1610                 error("Unable to open %s for writing", lockpath);
1611                 goto error_free_return;
1612         }
1613         written = write_in_full(fd, ref, len);
1614         if (close(fd) != 0 || written != len) {
1615                 error("Unable to write to %s", lockpath);
1616                 goto error_unlink_return;
1617         }
1618         if (rename(lockpath, git_HEAD) < 0) {
1619                 error("Unable to create %s", git_HEAD);
1620                 goto error_unlink_return;
1621         }
1622         if (adjust_shared_perm(git_HEAD)) {
1623                 error("Unable to fix permissions on %s", lockpath);
1624         error_unlink_return:
1625                 unlink_or_warn(lockpath);
1626         error_free_return:
1627                 free(git_HEAD);
1628                 return -1;
1629         }
1630
1631 #ifndef NO_SYMLINK_HEAD
1632         done:
1633 #endif
1634         if (logmsg && !read_ref(refs_heads_master, new_sha1))
1635                 log_ref_write(ref_target, old_sha1, new_sha1, logmsg);
1636
1637         free(git_HEAD);
1638         return 0;
1639 }
1640
1641 static char *ref_msg(const char *line, const char *endp)
1642 {
1643         const char *ep;
1644         line += 82;
1645         ep = memchr(line, '\n', endp - line);
1646         if (!ep)
1647                 ep = endp;
1648         return xmemdupz(line, ep - line);
1649 }
1650
1651 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)
1652 {
1653         const char *logfile, *logdata, *logend, *rec, *lastgt, *lastrec;
1654         char *tz_c;
1655         int logfd, tz, reccnt = 0;
1656         struct stat st;
1657         unsigned long date;
1658         unsigned char logged_sha1[20];
1659         void *log_mapped;
1660         size_t mapsz;
1661
1662         logfile = git_path("logs/%s", ref);
1663         logfd = open(logfile, O_RDONLY, 0);
1664         if (logfd < 0)
1665                 die_errno("Unable to read log '%s'", logfile);
1666         fstat(logfd, &st);
1667         if (!st.st_size)
1668                 die("Log %s is empty.", logfile);
1669         mapsz = xsize_t(st.st_size);
1670         log_mapped = xmmap(NULL, mapsz, PROT_READ, MAP_PRIVATE, logfd, 0);
1671         logdata = log_mapped;
1672         close(logfd);
1673
1674         lastrec = NULL;
1675         rec = logend = logdata + st.st_size;
1676         while (logdata < rec) {
1677                 reccnt++;
1678                 if (logdata < rec && *(rec-1) == '\n')
1679                         rec--;
1680                 lastgt = NULL;
1681                 while (logdata < rec && *(rec-1) != '\n') {
1682                         rec--;
1683                         if (*rec == '>')
1684                                 lastgt = rec;
1685                 }
1686                 if (!lastgt)
1687                         die("Log %s is corrupt.", logfile);
1688                 date = strtoul(lastgt + 1, &tz_c, 10);
1689                 if (date <= at_time || cnt == 0) {
1690                         tz = strtoul(tz_c, NULL, 10);
1691                         if (msg)
1692                                 *msg = ref_msg(rec, logend);
1693                         if (cutoff_time)
1694                                 *cutoff_time = date;
1695                         if (cutoff_tz)
1696                                 *cutoff_tz = tz;
1697                         if (cutoff_cnt)
1698                                 *cutoff_cnt = reccnt - 1;
1699                         if (lastrec) {
1700                                 if (get_sha1_hex(lastrec, logged_sha1))
1701                                         die("Log %s is corrupt.", logfile);
1702                                 if (get_sha1_hex(rec + 41, sha1))
1703                                         die("Log %s is corrupt.", logfile);
1704                                 if (hashcmp(logged_sha1, sha1)) {
1705                                         warning("Log %s has gap after %s.",
1706                                                 logfile, show_date(date, tz, DATE_RFC2822));
1707                                 }
1708                         }
1709                         else if (date == at_time) {
1710                                 if (get_sha1_hex(rec + 41, sha1))
1711                                         die("Log %s is corrupt.", logfile);
1712                         }
1713                         else {
1714                                 if (get_sha1_hex(rec + 41, logged_sha1))
1715                                         die("Log %s is corrupt.", logfile);
1716                                 if (hashcmp(logged_sha1, sha1)) {
1717                                         warning("Log %s unexpectedly ended on %s.",
1718                                                 logfile, show_date(date, tz, DATE_RFC2822));
1719                                 }
1720                         }
1721                         munmap(log_mapped, mapsz);
1722                         return 0;
1723                 }
1724                 lastrec = rec;
1725                 if (cnt > 0)
1726                         cnt--;
1727         }
1728
1729         rec = logdata;
1730         while (rec < logend && *rec != '>' && *rec != '\n')
1731                 rec++;
1732         if (rec == logend || *rec == '\n')
1733                 die("Log %s is corrupt.", logfile);
1734         date = strtoul(rec + 1, &tz_c, 10);
1735         tz = strtoul(tz_c, NULL, 10);
1736         if (get_sha1_hex(logdata, sha1))
1737                 die("Log %s is corrupt.", logfile);
1738         if (is_null_sha1(sha1)) {
1739                 if (get_sha1_hex(logdata + 41, sha1))
1740                         die("Log %s is corrupt.", logfile);
1741         }
1742         if (msg)
1743                 *msg = ref_msg(logdata, logend);
1744         munmap(log_mapped, mapsz);
1745
1746         if (cutoff_time)
1747                 *cutoff_time = date;
1748         if (cutoff_tz)
1749                 *cutoff_tz = tz;
1750         if (cutoff_cnt)
1751                 *cutoff_cnt = reccnt;
1752         return 1;
1753 }
1754
1755 int for_each_recent_reflog_ent(const char *ref, each_reflog_ent_fn fn, long ofs, void *cb_data)
1756 {
1757         const char *logfile;
1758         FILE *logfp;
1759         struct strbuf sb = STRBUF_INIT;
1760         int ret = 0;
1761
1762         logfile = git_path("logs/%s", ref);
1763         logfp = fopen(logfile, "r");
1764         if (!logfp)
1765                 return -1;
1766
1767         if (ofs) {
1768                 struct stat statbuf;
1769                 if (fstat(fileno(logfp), &statbuf) ||
1770                     statbuf.st_size < ofs ||
1771                     fseek(logfp, -ofs, SEEK_END) ||
1772                     strbuf_getwholeline(&sb, logfp, '\n')) {
1773                         fclose(logfp);
1774                         strbuf_release(&sb);
1775                         return -1;
1776                 }
1777         }
1778
1779         while (!strbuf_getwholeline(&sb, logfp, '\n')) {
1780                 unsigned char osha1[20], nsha1[20];
1781                 char *email_end, *message;
1782                 unsigned long timestamp;
1783                 int tz;
1784
1785                 /* old SP new SP name <email> SP time TAB msg LF */
1786                 if (sb.len < 83 || sb.buf[sb.len - 1] != '\n' ||
1787                     get_sha1_hex(sb.buf, osha1) || sb.buf[40] != ' ' ||
1788                     get_sha1_hex(sb.buf + 41, nsha1) || sb.buf[81] != ' ' ||
1789                     !(email_end = strchr(sb.buf + 82, '>')) ||
1790                     email_end[1] != ' ' ||
1791                     !(timestamp = strtoul(email_end + 2, &message, 10)) ||
1792                     !message || message[0] != ' ' ||
1793                     (message[1] != '+' && message[1] != '-') ||
1794                     !isdigit(message[2]) || !isdigit(message[3]) ||
1795                     !isdigit(message[4]) || !isdigit(message[5]))
1796                         continue; /* corrupt? */
1797                 email_end[1] = '\0';
1798                 tz = strtol(message + 1, NULL, 10);
1799                 if (message[6] != '\t')
1800                         message += 6;
1801                 else
1802                         message += 7;
1803                 ret = fn(osha1, nsha1, sb.buf + 82, timestamp, tz, message,
1804                          cb_data);
1805                 if (ret)
1806                         break;
1807         }
1808         fclose(logfp);
1809         strbuf_release(&sb);
1810         return ret;
1811 }
1812
1813 int for_each_reflog_ent(const char *ref, each_reflog_ent_fn fn, void *cb_data)
1814 {
1815         return for_each_recent_reflog_ent(ref, fn, 0, cb_data);
1816 }
1817
1818 static int do_for_each_reflog(const char *base, each_ref_fn fn, void *cb_data)
1819 {
1820         DIR *dir = opendir(git_path("logs/%s", base));
1821         int retval = 0;
1822
1823         if (dir) {
1824                 struct dirent *de;
1825                 int baselen = strlen(base);
1826                 char *log = xmalloc(baselen + 257);
1827
1828                 memcpy(log, base, baselen);
1829                 if (baselen && base[baselen-1] != '/')
1830                         log[baselen++] = '/';
1831
1832                 while ((de = readdir(dir)) != NULL) {
1833                         struct stat st;
1834                         int namelen;
1835
1836                         if (de->d_name[0] == '.')
1837                                 continue;
1838                         namelen = strlen(de->d_name);
1839                         if (namelen > 255)
1840                                 continue;
1841                         if (has_extension(de->d_name, ".lock"))
1842                                 continue;
1843                         memcpy(log + baselen, de->d_name, namelen+1);
1844                         if (stat(git_path("logs/%s", log), &st) < 0)
1845                                 continue;
1846                         if (S_ISDIR(st.st_mode)) {
1847                                 retval = do_for_each_reflog(log, fn, cb_data);
1848                         } else {
1849                                 unsigned char sha1[20];
1850                                 if (!resolve_ref(log, sha1, 0, NULL))
1851                                         retval = error("bad ref for %s", log);
1852                                 else
1853                                         retval = fn(log, sha1, 0, cb_data);
1854                         }
1855                         if (retval)
1856                                 break;
1857                 }
1858                 free(log);
1859                 closedir(dir);
1860         }
1861         else if (*base)
1862                 return errno;
1863         return retval;
1864 }
1865
1866 int for_each_reflog(each_ref_fn fn, void *cb_data)
1867 {
1868         return do_for_each_reflog("", fn, cb_data);
1869 }
1870
1871 int update_ref(const char *action, const char *refname,
1872                 const unsigned char *sha1, const unsigned char *oldval,
1873                 int flags, enum action_on_err onerr)
1874 {
1875         static struct ref_lock *lock;
1876         lock = lock_any_ref_for_update(refname, oldval, flags);
1877         if (!lock) {
1878                 const char *str = "Cannot lock the ref '%s'.";
1879                 switch (onerr) {
1880                 case MSG_ON_ERR: error(str, refname); break;
1881                 case DIE_ON_ERR: die(str, refname); break;
1882                 case QUIET_ON_ERR: break;
1883                 }
1884                 return 1;
1885         }
1886         if (write_ref_sha1(lock, sha1, action) < 0) {
1887                 const char *str = "Cannot update the ref '%s'.";
1888                 switch (onerr) {
1889                 case MSG_ON_ERR: error(str, refname); break;
1890                 case DIE_ON_ERR: die(str, refname); break;
1891                 case QUIET_ON_ERR: break;
1892                 }
1893                 return 1;
1894         }
1895         return 0;
1896 }
1897
1898 int ref_exists(const char *refname)
1899 {
1900         unsigned char sha1[20];
1901         return !!resolve_ref(refname, sha1, 1, NULL);
1902 }
1903
1904 struct ref *find_ref_by_name(const struct ref *list, const char *name)
1905 {
1906         for ( ; list; list = list->next)
1907                 if (!strcmp(list->name, name))
1908                         return (struct ref *)list;
1909         return NULL;
1910 }
1911
1912 /*
1913  * generate a format suitable for scanf from a ref_rev_parse_rules
1914  * rule, that is replace the "%.*s" spec with a "%s" spec
1915  */
1916 static void gen_scanf_fmt(char *scanf_fmt, const char *rule)
1917 {
1918         char *spec;
1919
1920         spec = strstr(rule, "%.*s");
1921         if (!spec || strstr(spec + 4, "%.*s"))
1922                 die("invalid rule in ref_rev_parse_rules: %s", rule);
1923
1924         /* copy all until spec */
1925         strncpy(scanf_fmt, rule, spec - rule);
1926         scanf_fmt[spec - rule] = '\0';
1927         /* copy new spec */
1928         strcat(scanf_fmt, "%s");
1929         /* copy remaining rule */
1930         strcat(scanf_fmt, spec + 4);
1931
1932         return;
1933 }
1934
1935 char *shorten_unambiguous_ref(const char *ref, int strict)
1936 {
1937         int i;
1938         static char **scanf_fmts;
1939         static int nr_rules;
1940         char *short_name;
1941
1942         /* pre generate scanf formats from ref_rev_parse_rules[] */
1943         if (!nr_rules) {
1944                 size_t total_len = 0;
1945
1946                 /* the rule list is NULL terminated, count them first */
1947                 for (; ref_rev_parse_rules[nr_rules]; nr_rules++)
1948                         /* no +1 because strlen("%s") < strlen("%.*s") */
1949                         total_len += strlen(ref_rev_parse_rules[nr_rules]);
1950
1951                 scanf_fmts = xmalloc(nr_rules * sizeof(char *) + total_len);
1952
1953                 total_len = 0;
1954                 for (i = 0; i < nr_rules; i++) {
1955                         scanf_fmts[i] = (char *)&scanf_fmts[nr_rules]
1956                                         + total_len;
1957                         gen_scanf_fmt(scanf_fmts[i], ref_rev_parse_rules[i]);
1958                         total_len += strlen(ref_rev_parse_rules[i]);
1959                 }
1960         }
1961
1962         /* bail out if there are no rules */
1963         if (!nr_rules)
1964                 return xstrdup(ref);
1965
1966         /* buffer for scanf result, at most ref must fit */
1967         short_name = xstrdup(ref);
1968
1969         /* skip first rule, it will always match */
1970         for (i = nr_rules - 1; i > 0 ; --i) {
1971                 int j;
1972                 int rules_to_fail = i;
1973                 int short_name_len;
1974
1975                 if (1 != sscanf(ref, scanf_fmts[i], short_name))
1976                         continue;
1977
1978                 short_name_len = strlen(short_name);
1979
1980                 /*
1981                  * in strict mode, all (except the matched one) rules
1982                  * must fail to resolve to a valid non-ambiguous ref
1983                  */
1984                 if (strict)
1985                         rules_to_fail = nr_rules;
1986
1987                 /*
1988                  * check if the short name resolves to a valid ref,
1989                  * but use only rules prior to the matched one
1990                  */
1991                 for (j = 0; j < rules_to_fail; j++) {
1992                         const char *rule = ref_rev_parse_rules[j];
1993                         unsigned char short_objectname[20];
1994                         char refname[PATH_MAX];
1995
1996                         /* skip matched rule */
1997                         if (i == j)
1998                                 continue;
1999
2000                         /*
2001                          * the short name is ambiguous, if it resolves
2002                          * (with this previous rule) to a valid ref
2003                          * read_ref() returns 0 on success
2004                          */
2005                         mksnpath(refname, sizeof(refname),
2006                                  rule, short_name_len, short_name);
2007                         if (!read_ref(refname, short_objectname))
2008                                 break;
2009                 }
2010
2011                 /*
2012                  * short name is non-ambiguous if all previous rules
2013                  * haven't resolved to a valid ref
2014                  */
2015                 if (j == rules_to_fail)
2016                         return short_name;
2017         }
2018
2019         free(short_name);
2020         return xstrdup(ref);
2021 }