refs.c

   1 /*
   2  * The backend-independent part of the reference module.
   3  */
   4
   5 #include "cache.h"
   6 #include "lockfile.h"
   7 #include "refs.h"
   8 #include "refs/refs-internal.h"
   9 #include "object.h"
  10 #include "tag.h"
  11
  12 /*
  13  * How to handle various characters in refnames:
  14  * 0: An acceptable character for refs
  15  * 1: End-of-component
  16  * 2: ., look for a preceding . to reject .. in refs
  17  * 3: {, look for a preceding @ to reject @{ in refs
  18  * 4: A bad character: ASCII control characters, and
  19  *    ":", "?", "[", "\", "^", "~", SP, or TAB
  20  * 5: *, reject unless REFNAME_REFSPEC_PATTERN is set
  21  */
  22 static unsigned char refname_disposition[256] = {
  23         1, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
  24         4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
  25         4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 5, 0, 0, 0, 2, 1,
  26         0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4, 0, 0, 0, 0, 4,
  27         0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
  28         0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4, 4, 0, 4, 0,
  29         0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
  30         0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 3, 0, 0, 4, 4
  31 };
  32
  33 /*
  34  * Try to read one refname component from the front of refname.
  35  * Return the length of the component found, or -1 if the component is
  36  * not legal.  It is legal if it is something reasonable to have under
  37  * ".git/refs/"; We do not like it if:
  38  *
  39  * - any path component of it begins with ".", or
  40  * - it has double dots "..", or
  41  * - it has ASCII control characters, or
  42  * - it has ":", "?", "[", "\", "^", "~", SP, or TAB anywhere, or
  43  * - it has "*" anywhere unless REFNAME_REFSPEC_PATTERN is set, or
  44  * - it ends with a "/", or
  45  * - it ends with ".lock", or
  46  * - it contains a "@{" portion
  47  */
  48 static int check_refname_component(const char *refname, int *flags)
  49 {
  50         const char *cp;
  51         char last = '\0';
  52
  53         for (cp = refname; ; cp++) {
  54                 int ch = *cp & 255;
  55                 unsigned char disp = refname_disposition[ch];
  56                 switch (disp) {
  57                 case 1:
  58                         goto out;
  59                 case 2:
  60                         if (last == '.')
  61                                 return -1; /* Refname contains "..". */
  62                         break;
  63                 case 3:
  64                         if (last == '@')
  65                                 return -1; /* Refname contains "@{". */
  66                         break;
  67                 case 4:
  68                         return -1;
  69                 case 5:
  70                         if (!(*flags & REFNAME_REFSPEC_PATTERN))
  71                                 return -1; /* refspec can't be a pattern */
  72
  73                         /*
  74                          * Unset the pattern flag so that we only accept
  75                          * a single asterisk for one side of refspec.
  76                          */
  77                         *flags &= ~ REFNAME_REFSPEC_PATTERN;
  78                         break;
  79                 }
  80                 last = ch;
  81         }
  82 out:
  83         if (cp == refname)
  84                 return 0; /* Component has zero length. */
  85         if (refname[0] == '.')
  86                 return -1; /* Component starts with '.'. */
  87         if (cp - refname >= LOCK_SUFFIX_LEN &&
  88             !memcmp(cp - LOCK_SUFFIX_LEN, LOCK_SUFFIX, LOCK_SUFFIX_LEN))
  89                 return -1; /* Refname ends with ".lock". */
  90         return cp - refname;
  91 }
  92
  93 int check_refname_format(const char *refname, int flags)
  94 {
  95         int component_len, component_count = 0;
  96
  97         if (!strcmp(refname, "@"))
  98                 /* Refname is a single character '@'. */
  99                 return -1;
 100
 101         while (1) {
 102                 /* We are at the start of a path component. */
 103                 component_len = check_refname_component(refname, &flags);
 104                 if (component_len <= 0)
 105                         return -1;
 106
 107                 component_count++;
 108                 if (refname[component_len] == '\0')
 109                         break;
 110                 /* Skip to next component. */
 111                 refname += component_len + 1;
 112         }
 113
 114         if (refname[component_len - 1] == '.')
 115                 return -1; /* Refname ends with '.'. */
 116         if (!(flags & REFNAME_ALLOW_ONELEVEL) && component_count < 2)
 117                 return -1; /* Refname has only one component. */
 118         return 0;
 119 }
 120
 121 int refname_is_safe(const char *refname)
 122 {
 123         if (starts_with(refname, "refs/")) {
 124                 char *buf;
 125                 int result;
 126
 127                 buf = xmallocz(strlen(refname));
 128                 /*
 129                  * Does the refname try to escape refs/?
 130                  * For example: refs/foo/../bar is safe but refs/foo/../../bar
 131                  * is not.
 132                  */
 133                 result = !normalize_path_copy(buf, refname + strlen("refs/"));
 134                 free(buf);
 135                 return result;
 136         }
 137         while (*refname) {
 138                 if (!isupper(*refname) && *refname != '_')
 139                         return 0;
 140                 refname++;
 141         }
 142         return 1;
 143 }
 144
 145 char *resolve_refdup(const char *refname, int resolve_flags,
 146                      unsigned char *sha1, int *flags)
 147 {
 148         return xstrdup_or_null(resolve_ref_unsafe(refname, resolve_flags,
 149                                                   sha1, flags));
 150 }
 151
 152 /* The argument to filter_refs */
 153 struct ref_filter {
 154         const char *pattern;
 155         each_ref_fn *fn;
 156         void *cb_data;
 157 };
 158
 159 int read_ref_full(const char *refname, int resolve_flags, unsigned char *sha1, int *flags)
 160 {
 161         if (resolve_ref_unsafe(refname, resolve_flags, sha1, flags))
 162                 return 0;
 163         return -1;
 164 }
 165
 166 int read_ref(const char *refname, unsigned char *sha1)
 167 {
 168         return read_ref_full(refname, RESOLVE_REF_READING, sha1, NULL);
 169 }
 170
 171 int ref_exists(const char *refname)
 172 {
 173         unsigned char sha1[20];
 174         return !!resolve_ref_unsafe(refname, RESOLVE_REF_READING, sha1, NULL);
 175 }
 176
 177 static int filter_refs(const char *refname, const struct object_id *oid,
 178                            int flags, void *data)
 179 {
 180         struct ref_filter *filter = (struct ref_filter *)data;
 181
 182         if (wildmatch(filter->pattern, refname, 0, NULL))
 183                 return 0;
 184         return filter->fn(refname, oid, flags, filter->cb_data);
 185 }
 186
 187 enum peel_status peel_object(const unsigned char *name, unsigned char *sha1)
 188 {
 189         struct object *o = lookup_unknown_object(name);
 190
 191         if (o->type == OBJ_NONE) {
 192                 int type = sha1_object_info(name, NULL);
 193                 if (type < 0 || !object_as_type(o, type, 0))
 194                         return PEEL_INVALID;
 195         }
 196
 197         if (o->type != OBJ_TAG)
 198                 return PEEL_NON_TAG;
 199
 200         o = deref_tag_noverify(o);
 201         if (!o)
 202                 return PEEL_INVALID;
 203
 204         hashcpy(sha1, o->oid.hash);
 205         return PEEL_PEELED;
 206 }
 207
 208 struct warn_if_dangling_data {
 209         FILE *fp;
 210         const char *refname;
 211         const struct string_list *refnames;
 212         const char *msg_fmt;
 213 };
 214
 215 static int warn_if_dangling_symref(const char *refname, const struct object_id *oid,
 216                                    int flags, void *cb_data)
 217 {
 218         struct warn_if_dangling_data *d = cb_data;
 219         const char *resolves_to;
 220         struct object_id junk;
 221
 222         if (!(flags & REF_ISSYMREF))
 223                 return 0;
 224
 225         resolves_to = resolve_ref_unsafe(refname, 0, junk.hash, NULL);
 226         if (!resolves_to
 227             || (d->refname
 228                 ? strcmp(resolves_to, d->refname)
 229                 : !string_list_has_string(d->refnames, resolves_to))) {
 230                 return 0;
 231         }
 232
 233         fprintf(d->fp, d->msg_fmt, refname);
 234         fputc('\n', d->fp);
 235         return 0;
 236 }
 237
 238 void warn_dangling_symref(FILE *fp, const char *msg_fmt, const char *refname)
 239 {
 240         struct warn_if_dangling_data data;
 241
 242         data.fp = fp;
 243         data.refname = refname;
 244         data.refnames = NULL;
 245         data.msg_fmt = msg_fmt;
 246         for_each_rawref(warn_if_dangling_symref, &data);
 247 }
 248
 249 void warn_dangling_symrefs(FILE *fp, const char *msg_fmt, const struct string_list *refnames)
 250 {
 251         struct warn_if_dangling_data data;
 252
 253         data.fp = fp;
 254         data.refname = NULL;
 255         data.refnames = refnames;
 256         data.msg_fmt = msg_fmt;
 257         for_each_rawref(warn_if_dangling_symref, &data);
 258 }
 259
 260 int for_each_tag_ref(each_ref_fn fn, void *cb_data)
 261 {
 262         return for_each_ref_in("refs/tags/", fn, cb_data);
 263 }
 264
 265 int for_each_tag_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
 266 {
 267         return for_each_ref_in_submodule(submodule, "refs/tags/", fn, cb_data);
 268 }
 269
 270 int for_each_branch_ref(each_ref_fn fn, void *cb_data)
 271 {
 272         return for_each_ref_in("refs/heads/", fn, cb_data);
 273 }
 274
 275 int for_each_branch_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
 276 {
 277         return for_each_ref_in_submodule(submodule, "refs/heads/", fn, cb_data);
 278 }
 279
 280 int for_each_remote_ref(each_ref_fn fn, void *cb_data)
 281 {
 282         return for_each_ref_in("refs/remotes/", fn, cb_data);
 283 }
 284
 285 int for_each_remote_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
 286 {
 287         return for_each_ref_in_submodule(submodule, "refs/remotes/", fn, cb_data);
 288 }
 289
 290 int head_ref_namespaced(each_ref_fn fn, void *cb_data)
 291 {
 292         struct strbuf buf = STRBUF_INIT;
 293         int ret = 0;
 294         struct object_id oid;
 295         int flag;
 296
 297         strbuf_addf(&buf, "%sHEAD", get_git_namespace());
 298         if (!read_ref_full(buf.buf, RESOLVE_REF_READING, oid.hash, &flag))
 299                 ret = fn(buf.buf, &oid, flag, cb_data);
 300         strbuf_release(&buf);
 301
 302         return ret;
 303 }
 304
 305 int for_each_glob_ref_in(each_ref_fn fn, const char *pattern,
 306         const char *prefix, void *cb_data)
 307 {
 308         struct strbuf real_pattern = STRBUF_INIT;
 309         struct ref_filter filter;
 310         int ret;
 311
 312         if (!prefix && !starts_with(pattern, "refs/"))
 313                 strbuf_addstr(&real_pattern, "refs/");
 314         else if (prefix)
 315                 strbuf_addstr(&real_pattern, prefix);
 316         strbuf_addstr(&real_pattern, pattern);
 317
 318         if (!has_glob_specials(pattern)) {
 319                 /* Append implied '/' '*' if not present. */
 320                 strbuf_complete(&real_pattern, '/');
 321                 /* No need to check for '*', there is none. */
 322                 strbuf_addch(&real_pattern, '*');
 323         }
 324
 325         filter.pattern = real_pattern.buf;
 326         filter.fn = fn;
 327         filter.cb_data = cb_data;
 328         ret = for_each_ref(filter_refs, &filter);
 329
 330         strbuf_release(&real_pattern);
 331         return ret;
 332 }
 333
 334 int for_each_glob_ref(each_ref_fn fn, const char *pattern, void *cb_data)
 335 {
 336         return for_each_glob_ref_in(fn, pattern, NULL, cb_data);
 337 }
 338
 339 const char *prettify_refname(const char *name)
 340 {
 341         return name + (
 342                 starts_with(name, "refs/heads/") ? 11 :
 343                 starts_with(name, "refs/tags/") ? 10 :
 344                 starts_with(name, "refs/remotes/") ? 13 :
 345                 0);
 346 }
 347
 348 static const char *ref_rev_parse_rules[] = {
 349         "%.*s",
 350         "refs/%.*s",
 351         "refs/tags/%.*s",
 352         "refs/heads/%.*s",
 353         "refs/remotes/%.*s",
 354         "refs/remotes/%.*s/HEAD",
 355         NULL
 356 };
 357
 358 int refname_match(const char *abbrev_name, const char *full_name)
 359 {
 360         const char **p;
 361         const int abbrev_name_len = strlen(abbrev_name);
 362
 363         for (p = ref_rev_parse_rules; *p; p++) {
 364                 if (!strcmp(full_name, mkpath(*p, abbrev_name_len, abbrev_name))) {
 365                         return 1;
 366                 }
 367         }
 368
 369         return 0;
 370 }
 371
 372 /*
 373  * *string and *len will only be substituted, and *string returned (for
 374  * later free()ing) if the string passed in is a magic short-hand form
 375  * to name a branch.
 376  */
 377 static char *substitute_branch_name(const char **string, int *len)
 378 {
 379         struct strbuf buf = STRBUF_INIT;
 380         int ret = interpret_branch_name(*string, *len, &buf);
 381
 382         if (ret == *len) {
 383                 size_t size;
 384                 *string = strbuf_detach(&buf, &size);
 385                 *len = size;
 386                 return (char *)*string;
 387         }
 388
 389         return NULL;
 390 }
 391
 392 int dwim_ref(const char *str, int len, unsigned char *sha1, char **ref)
 393 {
 394         char *last_branch = substitute_branch_name(&str, &len);
 395         const char **p, *r;
 396         int refs_found = 0;
 397
 398         *ref = NULL;
 399         for (p = ref_rev_parse_rules; *p; p++) {
 400                 char fullref[PATH_MAX];
 401                 unsigned char sha1_from_ref[20];
 402                 unsigned char *this_result;
 403                 int flag;
 404
 405                 this_result = refs_found ? sha1_from_ref : sha1;
 406                 mksnpath(fullref, sizeof(fullref), *p, len, str);
 407                 r = resolve_ref_unsafe(fullref, RESOLVE_REF_READING,
 408                                        this_result, &flag);
 409                 if (r) {
 410                         if (!refs_found++)
 411                                 *ref = xstrdup(r);
 412                         if (!warn_ambiguous_refs)
 413                                 break;
 414                 } else if ((flag & REF_ISSYMREF) && strcmp(fullref, "HEAD")) {
 415                         warning("ignoring dangling symref %s.", fullref);
 416                 } else if ((flag & REF_ISBROKEN) && strchr(fullref, '/')) {
 417                         warning("ignoring broken ref %s.", fullref);
 418                 }
 419         }
 420         free(last_branch);
 421         return refs_found;
 422 }
 423
 424 int dwim_log(const char *str, int len, unsigned char *sha1, char **log)
 425 {
 426         char *last_branch = substitute_branch_name(&str, &len);
 427         const char **p;
 428         int logs_found = 0;
 429
 430         *log = NULL;
 431         for (p = ref_rev_parse_rules; *p; p++) {
 432                 unsigned char hash[20];
 433                 char path[PATH_MAX];
 434                 const char *ref, *it;
 435
 436                 mksnpath(path, sizeof(path), *p, len, str);
 437                 ref = resolve_ref_unsafe(path, RESOLVE_REF_READING,
 438                                          hash, NULL);
 439                 if (!ref)
 440                         continue;
 441                 if (reflog_exists(path))
 442                         it = path;
 443                 else if (strcmp(ref, path) && reflog_exists(ref))
 444                         it = ref;
 445                 else
 446                         continue;
 447                 if (!logs_found++) {
 448                         *log = xstrdup(it);
 449                         hashcpy(sha1, hash);
 450                 }
 451                 if (!warn_ambiguous_refs)
 452                         break;
 453         }
 454         free(last_branch);
 455         return logs_found;
 456 }
 457
 458 static int is_per_worktree_ref(const char *refname)
 459 {
 460         return !strcmp(refname, "HEAD") ||
 461                 starts_with(refname, "refs/bisect/");
 462 }
 463
 464 static int is_pseudoref_syntax(const char *refname)
 465 {
 466         const char *c;
 467
 468         for (c = refname; *c; c++) {
 469                 if (!isupper(*c) && *c != '-' && *c != '_')
 470                         return 0;
 471         }
 472
 473         return 1;
 474 }
 475
 476 enum ref_type ref_type(const char *refname)
 477 {
 478         if (is_per_worktree_ref(refname))
 479                 return REF_TYPE_PER_WORKTREE;
 480         if (is_pseudoref_syntax(refname))
 481                 return REF_TYPE_PSEUDOREF;
 482        return REF_TYPE_NORMAL;
 483 }
 484
 485 static int write_pseudoref(const char *pseudoref, const unsigned char *sha1,
 486                            const unsigned char *old_sha1, struct strbuf *err)
 487 {
 488         const char *filename;
 489         int fd;
 490         static struct lock_file lock;
 491         struct strbuf buf = STRBUF_INIT;
 492         int ret = -1;
 493
 494         strbuf_addf(&buf, "%s\n", sha1_to_hex(sha1));
 495
 496         filename = git_path("%s", pseudoref);
 497         fd = hold_lock_file_for_update(&lock, filename, LOCK_DIE_ON_ERROR);
 498         if (fd < 0) {
 499                 strbuf_addf(err, "Could not open '%s' for writing: %s",
 500                             filename, strerror(errno));
 501                 return -1;
 502         }
 503
 504         if (old_sha1) {
 505                 unsigned char actual_old_sha1[20];
 506
 507                 if (read_ref(pseudoref, actual_old_sha1))
 508                         die("could not read ref '%s'", pseudoref);
 509                 if (hashcmp(actual_old_sha1, old_sha1)) {
 510                         strbuf_addf(err, "Unexpected sha1 when writing %s", pseudoref);
 511                         rollback_lock_file(&lock);
 512                         goto done;
 513                 }
 514         }
 515
 516         if (write_in_full(fd, buf.buf, buf.len) != buf.len) {
 517                 strbuf_addf(err, "Could not write to '%s'", filename);
 518                 rollback_lock_file(&lock);
 519                 goto done;
 520         }
 521
 522         commit_lock_file(&lock);
 523         ret = 0;
 524 done:
 525         strbuf_release(&buf);
 526         return ret;
 527 }
 528
 529 static int delete_pseudoref(const char *pseudoref, const unsigned char *old_sha1)
 530 {
 531         static struct lock_file lock;
 532         const char *filename;
 533
 534         filename = git_path("%s", pseudoref);
 535
 536         if (old_sha1 && !is_null_sha1(old_sha1)) {
 537                 int fd;
 538                 unsigned char actual_old_sha1[20];
 539
 540                 fd = hold_lock_file_for_update(&lock, filename,
 541                                                LOCK_DIE_ON_ERROR);
 542                 if (fd < 0)
 543                         die_errno(_("Could not open '%s' for writing"), filename);
 544                 if (read_ref(pseudoref, actual_old_sha1))
 545                         die("could not read ref '%s'", pseudoref);
 546                 if (hashcmp(actual_old_sha1, old_sha1)) {
 547                         warning("Unexpected sha1 when deleting %s", pseudoref);
 548                         rollback_lock_file(&lock);
 549                         return -1;
 550                 }
 551
 552                 unlink(filename);
 553                 rollback_lock_file(&lock);
 554         } else {
 555                 unlink(filename);
 556         }
 557
 558         return 0;
 559 }
 560
 561 int delete_ref(const char *refname, const unsigned char *old_sha1,
 562                unsigned int flags)
 563 {
 564         struct ref_transaction *transaction;
 565         struct strbuf err = STRBUF_INIT;
 566
 567         if (ref_type(refname) == REF_TYPE_PSEUDOREF)
 568                 return delete_pseudoref(refname, old_sha1);
 569
 570         transaction = ref_transaction_begin(&err);
 571         if (!transaction ||
 572             ref_transaction_delete(transaction, refname, old_sha1,
 573                                    flags, NULL, &err) ||
 574             ref_transaction_commit(transaction, &err)) {
 575                 error("%s", err.buf);
 576                 ref_transaction_free(transaction);
 577                 strbuf_release(&err);
 578                 return 1;
 579         }
 580         ref_transaction_free(transaction);
 581         strbuf_release(&err);
 582         return 0;
 583 }
 584
 585 int copy_reflog_msg(char *buf, const char *msg)
 586 {
 587         char *cp = buf;
 588         char c;
 589         int wasspace = 1;
 590
 591         *cp++ = '\t';
 592         while ((c = *msg++)) {
 593                 if (wasspace && isspace(c))
 594                         continue;
 595                 wasspace = isspace(c);
 596                 if (wasspace)
 597                         c = ' ';
 598                 *cp++ = c;
 599         }
 600         while (buf < cp && isspace(cp[-1]))
 601                 cp--;
 602         *cp++ = '\n';
 603         return cp - buf;
 604 }
 605
 606 int should_autocreate_reflog(const char *refname)
 607 {
 608         if (!log_all_ref_updates)
 609                 return 0;
 610         return starts_with(refname, "refs/heads/") ||
 611                 starts_with(refname, "refs/remotes/") ||
 612                 starts_with(refname, "refs/notes/") ||
 613                 !strcmp(refname, "HEAD");
 614 }
 615
 616 int is_branch(const char *refname)
 617 {
 618         return !strcmp(refname, "HEAD") || starts_with(refname, "refs/heads/");
 619 }
 620
 621 struct read_ref_at_cb {
 622         const char *refname;
 623         unsigned long at_time;
 624         int cnt;
 625         int reccnt;
 626         unsigned char *sha1;
 627         int found_it;
 628
 629         unsigned char osha1[20];
 630         unsigned char nsha1[20];
 631         int tz;
 632         unsigned long date;
 633         char **msg;
 634         unsigned long *cutoff_time;
 635         int *cutoff_tz;
 636         int *cutoff_cnt;
 637 };
 638
 639 static int read_ref_at_ent(unsigned char *osha1, unsigned char *nsha1,
 640                 const char *email, unsigned long timestamp, int tz,
 641                 const char *message, void *cb_data)
 642 {
 643         struct read_ref_at_cb *cb = cb_data;
 644
 645         cb->reccnt++;
 646         cb->tz = tz;
 647         cb->date = timestamp;
 648
 649         if (timestamp <= cb->at_time || cb->cnt == 0) {
 650                 if (cb->msg)
 651                         *cb->msg = xstrdup(message);
 652                 if (cb->cutoff_time)
 653                         *cb->cutoff_time = timestamp;
 654                 if (cb->cutoff_tz)
 655                         *cb->cutoff_tz = tz;
 656                 if (cb->cutoff_cnt)
 657                         *cb->cutoff_cnt = cb->reccnt - 1;
 658                 /*
 659                  * we have not yet updated cb->[n|o]sha1 so they still
 660                  * hold the values for the previous record.
 661                  */
 662                 if (!is_null_sha1(cb->osha1)) {
 663                         hashcpy(cb->sha1, nsha1);
 664                         if (hashcmp(cb->osha1, nsha1))
 665                                 warning("Log for ref %s has gap after %s.",
 666                                         cb->refname, show_date(cb->date, cb->tz, DATE_MODE(RFC2822)));
 667                 }
 668                 else if (cb->date == cb->at_time)
 669                         hashcpy(cb->sha1, nsha1);
 670                 else if (hashcmp(nsha1, cb->sha1))
 671                         warning("Log for ref %s unexpectedly ended on %s.",
 672                                 cb->refname, show_date(cb->date, cb->tz,
 673                                                        DATE_MODE(RFC2822)));
 674                 hashcpy(cb->osha1, osha1);
 675                 hashcpy(cb->nsha1, nsha1);
 676                 cb->found_it = 1;
 677                 return 1;
 678         }
 679         hashcpy(cb->osha1, osha1);
 680         hashcpy(cb->nsha1, nsha1);
 681         if (cb->cnt > 0)
 682                 cb->cnt--;
 683         return 0;
 684 }
 685
 686 static int read_ref_at_ent_oldest(unsigned char *osha1, unsigned char *nsha1,
 687                                   const char *email, unsigned long timestamp,
 688                                   int tz, const char *message, void *cb_data)
 689 {
 690         struct read_ref_at_cb *cb = cb_data;
 691
 692         if (cb->msg)
 693                 *cb->msg = xstrdup(message);
 694         if (cb->cutoff_time)
 695                 *cb->cutoff_time = timestamp;
 696         if (cb->cutoff_tz)
 697                 *cb->cutoff_tz = tz;
 698         if (cb->cutoff_cnt)
 699                 *cb->cutoff_cnt = cb->reccnt;
 700         hashcpy(cb->sha1, osha1);
 701         if (is_null_sha1(cb->sha1))
 702                 hashcpy(cb->sha1, nsha1);
 703         /* We just want the first entry */
 704         return 1;
 705 }
 706
 707 int read_ref_at(const char *refname, unsigned int flags, unsigned long at_time, int cnt,
 708                 unsigned char *sha1, char **msg,
 709                 unsigned long *cutoff_time, int *cutoff_tz, int *cutoff_cnt)
 710 {
 711         struct read_ref_at_cb cb;
 712
 713         memset(&cb, 0, sizeof(cb));
 714         cb.refname = refname;
 715         cb.at_time = at_time;
 716         cb.cnt = cnt;
 717         cb.msg = msg;
 718         cb.cutoff_time = cutoff_time;
 719         cb.cutoff_tz = cutoff_tz;
 720         cb.cutoff_cnt = cutoff_cnt;
 721         cb.sha1 = sha1;
 722
 723         for_each_reflog_ent_reverse(refname, read_ref_at_ent, &cb);
 724
 725         if (!cb.reccnt) {
 726                 if (flags & GET_SHA1_QUIETLY)
 727                         exit(128);
 728                 else
 729                         die("Log for %s is empty.", refname);
 730         }
 731         if (cb.found_it)
 732                 return 0;
 733
 734         for_each_reflog_ent(refname, read_ref_at_ent_oldest, &cb);
 735
 736         return 1;
 737 }
 738
 739 struct ref_transaction *ref_transaction_begin(struct strbuf *err)
 740 {
 741         assert(err);
 742
 743         return xcalloc(1, sizeof(struct ref_transaction));
 744 }
 745
 746 void ref_transaction_free(struct ref_transaction *transaction)
 747 {
 748         int i;
 749
 750         if (!transaction)
 751                 return;
 752
 753         for (i = 0; i < transaction->nr; i++) {
 754                 free(transaction->updates[i]->msg);
 755                 free(transaction->updates[i]);
 756         }
 757         free(transaction->updates);
 758         free(transaction);
 759 }
 760
 761 static struct ref_update *add_update(struct ref_transaction *transaction,
 762                                      const char *refname)
 763 {
 764         struct ref_update *update;
 765         FLEX_ALLOC_STR(update, refname, refname);
 766         ALLOC_GROW(transaction->updates, transaction->nr + 1, transaction->alloc);
 767         transaction->updates[transaction->nr++] = update;
 768         return update;
 769 }
 770
 771 int ref_transaction_update(struct ref_transaction *transaction,
 772                            const char *refname,
 773                            const unsigned char *new_sha1,
 774                            const unsigned char *old_sha1,
 775                            unsigned int flags, const char *msg,
 776                            struct strbuf *err)
 777 {
 778         struct ref_update *update;
 779
 780         assert(err);
 781
 782         if (transaction->state != REF_TRANSACTION_OPEN)
 783                 die("BUG: update called for transaction that is not open");
 784
 785         if (new_sha1 && !is_null_sha1(new_sha1) &&
 786             check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
 787                 strbuf_addf(err, "refusing to update ref with bad name %s",
 788                             refname);
 789                 return -1;
 790         }
 791
 792         update = add_update(transaction, refname);
 793         if (new_sha1) {
 794                 hashcpy(update->new_sha1, new_sha1);
 795                 flags |= REF_HAVE_NEW;
 796         }
 797         if (old_sha1) {
 798                 hashcpy(update->old_sha1, old_sha1);
 799                 flags |= REF_HAVE_OLD;
 800         }
 801         update->flags = flags;
 802         if (msg)
 803                 update->msg = xstrdup(msg);
 804         return 0;
 805 }
 806
 807 int ref_transaction_create(struct ref_transaction *transaction,
 808                            const char *refname,
 809                            const unsigned char *new_sha1,
 810                            unsigned int flags, const char *msg,
 811                            struct strbuf *err)
 812 {
 813         if (!new_sha1 || is_null_sha1(new_sha1))
 814                 die("BUG: create called without valid new_sha1");
 815         return ref_transaction_update(transaction, refname, new_sha1,
 816                                       null_sha1, flags, msg, err);
 817 }
 818
 819 int ref_transaction_delete(struct ref_transaction *transaction,
 820                            const char *refname,
 821                            const unsigned char *old_sha1,
 822                            unsigned int flags, const char *msg,
 823                            struct strbuf *err)
 824 {
 825         if (old_sha1 && is_null_sha1(old_sha1))
 826                 die("BUG: delete called with old_sha1 set to zeros");
 827         return ref_transaction_update(transaction, refname,
 828                                       null_sha1, old_sha1,
 829                                       flags, msg, err);
 830 }
 831
 832 int ref_transaction_verify(struct ref_transaction *transaction,
 833                            const char *refname,
 834                            const unsigned char *old_sha1,
 835                            unsigned int flags,
 836                            struct strbuf *err)
 837 {
 838         if (!old_sha1)
 839                 die("BUG: verify called with old_sha1 set to NULL");
 840         return ref_transaction_update(transaction, refname,
 841                                       NULL, old_sha1,
 842                                       flags, NULL, err);
 843 }
 844
 845 int update_ref(const char *msg, const char *refname,
 846                const unsigned char *new_sha1, const unsigned char *old_sha1,
 847                unsigned int flags, enum action_on_err onerr)
 848 {
 849         struct ref_transaction *t = NULL;
 850         struct strbuf err = STRBUF_INIT;
 851         int ret = 0;
 852
 853         if (ref_type(refname) == REF_TYPE_PSEUDOREF) {
 854                 ret = write_pseudoref(refname, new_sha1, old_sha1, &err);
 855         } else {
 856                 t = ref_transaction_begin(&err);
 857                 if (!t ||
 858                     ref_transaction_update(t, refname, new_sha1, old_sha1,
 859                                            flags, msg, &err) ||
 860                     ref_transaction_commit(t, &err)) {
 861                         ret = 1;
 862                         ref_transaction_free(t);
 863                 }
 864         }
 865         if (ret) {
 866                 const char *str = "update_ref failed for ref '%s': %s";
 867
 868                 switch (onerr) {
 869                 case UPDATE_REFS_MSG_ON_ERR:
 870                         error(str, refname, err.buf);
 871                         break;
 872                 case UPDATE_REFS_DIE_ON_ERR:
 873                         die(str, refname, err.buf);
 874                         break;
 875                 case UPDATE_REFS_QUIET_ON_ERR:
 876                         break;
 877                 }
 878                 strbuf_release(&err);
 879                 return 1;
 880         }
 881         strbuf_release(&err);
 882         if (t)
 883                 ref_transaction_free(t);
 884         return 0;
 885 }
 886
 887 char *shorten_unambiguous_ref(const char *refname, int strict)
 888 {
 889         int i;
 890         static char **scanf_fmts;
 891         static int nr_rules;
 892         char *short_name;
 893
 894         if (!nr_rules) {
 895                 /*
 896                  * Pre-generate scanf formats from ref_rev_parse_rules[].
 897                  * Generate a format suitable for scanf from a
 898                  * ref_rev_parse_rules rule by interpolating "%s" at the
 899                  * location of the "%.*s".
 900                  */
 901                 size_t total_len = 0;
 902                 size_t offset = 0;
 903
 904                 /* the rule list is NULL terminated, count them first */
 905                 for (nr_rules = 0; ref_rev_parse_rules[nr_rules]; nr_rules++)
 906                         /* -2 for strlen("%.*s") - strlen("%s"); +1 for NUL */
 907                         total_len += strlen(ref_rev_parse_rules[nr_rules]) - 2 + 1;
 908
 909                 scanf_fmts = xmalloc(st_add(st_mult(nr_rules, sizeof(char *)), total_len));
 910
 911                 offset = 0;
 912                 for (i = 0; i < nr_rules; i++) {
 913                         assert(offset < total_len);
 914                         scanf_fmts[i] = (char *)&scanf_fmts[nr_rules] + offset;
 915                         offset += snprintf(scanf_fmts[i], total_len - offset,
 916                                            ref_rev_parse_rules[i], 2, "%s") + 1;
 917                 }
 918         }
 919
 920         /* bail out if there are no rules */
 921         if (!nr_rules)
 922                 return xstrdup(refname);
 923
 924         /* buffer for scanf result, at most refname must fit */
 925         short_name = xstrdup(refname);
 926
 927         /* skip first rule, it will always match */
 928         for (i = nr_rules - 1; i > 0 ; --i) {
 929                 int j;
 930                 int rules_to_fail = i;
 931                 int short_name_len;
 932
 933                 if (1 != sscanf(refname, scanf_fmts[i], short_name))
 934                         continue;
 935
 936                 short_name_len = strlen(short_name);
 937
 938                 /*
 939                  * in strict mode, all (except the matched one) rules
 940                  * must fail to resolve to a valid non-ambiguous ref
 941                  */
 942                 if (strict)
 943                         rules_to_fail = nr_rules;
 944
 945                 /*
 946                  * check if the short name resolves to a valid ref,
 947                  * but use only rules prior to the matched one
 948                  */
 949                 for (j = 0; j < rules_to_fail; j++) {
 950                         const char *rule = ref_rev_parse_rules[j];
 951                         char refname[PATH_MAX];
 952
 953                         /* skip matched rule */
 954                         if (i == j)
 955                                 continue;
 956
 957                         /*
 958                          * the short name is ambiguous, if it resolves
 959                          * (with this previous rule) to a valid ref
 960                          * read_ref() returns 0 on success
 961                          */
 962                         mksnpath(refname, sizeof(refname),
 963                                  rule, short_name_len, short_name);
 964                         if (ref_exists(refname))
 965                                 break;
 966                 }
 967
 968                 /*
 969                  * short name is non-ambiguous if all previous rules
 970                  * haven't resolved to a valid ref
 971                  */
 972                 if (j == rules_to_fail)
 973                         return short_name;
 974         }
 975
 976         free(short_name);
 977         return xstrdup(refname);
 978 }
 979
 980 static struct string_list *hide_refs;
 981
 982 int parse_hide_refs_config(const char *var, const char *value, const char *section)
 983 {
 984         if (!strcmp("transfer.hiderefs", var) ||
 985             /* NEEDSWORK: use parse_config_key() once both are merged */
 986             (starts_with(var, section) && var[strlen(section)] == '.' &&
 987              !strcmp(var + strlen(section), ".hiderefs"))) {
 988                 char *ref;
 989                 int len;
 990
 991                 if (!value)
 992                         return config_error_nonbool(var);
 993                 ref = xstrdup(value);
 994                 len = strlen(ref);
 995                 while (len && ref[len - 1] == '/')
 996                         ref[--len] = '\0';
 997                 if (!hide_refs) {
 998                         hide_refs = xcalloc(1, sizeof(*hide_refs));
 999                         hide_refs->strdup_strings = 1;
1000                 }
1001                 string_list_append(hide_refs, ref);
1002         }
1003         return 0;
1004 }
1005
1006 int ref_is_hidden(const char *refname, const char *refname_full)
1007 {
1008         int i;
1009
1010         if (!hide_refs)
1011                 return 0;
1012         for (i = hide_refs->nr - 1; i >= 0; i--) {
1013                 const char *match = hide_refs->items[i].string;
1014                 const char *subject;
1015                 int neg = 0;
1016                 int len;
1017
1018                 if (*match == '!') {
1019                         neg = 1;
1020                         match++;
1021                 }
1022
1023                 if (*match == '^') {
1024                         subject = refname_full;
1025                         match++;
1026                 } else {
1027                         subject = refname;
1028                 }
1029
1030                 /* refname can be NULL when namespaces are used. */
1031                 if (!subject || !starts_with(subject, match))
1032                         continue;
1033                 len = strlen(match);
1034                 if (!subject[len] || subject[len] == '/')
1035                         return !neg;
1036         }
1037         return 0;
1038 }
1039
1040 const char *find_descendant_ref(const char *dirname,
1041                                 const struct string_list *extras,
1042                                 const struct string_list *skip)
1043 {
1044         int pos;
1045
1046         if (!extras)
1047                 return NULL;
1048
1049         /*
1050          * Look at the place where dirname would be inserted into
1051          * extras. If there is an entry at that position that starts
1052          * with dirname (remember, dirname includes the trailing
1053          * slash) and is not in skip, then we have a conflict.
1054          */
1055         for (pos = string_list_find_insert_index(extras, dirname, 0);
1056              pos < extras->nr; pos++) {
1057                 const char *extra_refname = extras->items[pos].string;
1058
1059                 if (!starts_with(extra_refname, dirname))
1060                         break;
1061
1062                 if (!skip || !string_list_has_string(skip, extra_refname))
1063                         return extra_refname;
1064         }
1065         return NULL;
1066 }
1067
1068 int rename_ref_available(const char *oldname, const char *newname)
1069 {
1070         struct string_list skip = STRING_LIST_INIT_NODUP;
1071         struct strbuf err = STRBUF_INIT;
1072         int ret;
1073
1074         string_list_insert(&skip, oldname);
1075         ret = !verify_refname_available(newname, NULL, &skip, &err);
1076         if (!ret)
1077                 error("%s", err.buf);
1078
1079         string_list_clear(&skip, 0);
1080         strbuf_release(&err);
1081         return ret;
1082 }
1083
1084 int head_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
1085 {
1086         struct object_id oid;
1087         int flag;
1088
1089         if (submodule) {
1090                 if (resolve_gitlink_ref(submodule, "HEAD", oid.hash) == 0)
1091                         return fn("HEAD", &oid, 0, cb_data);
1092
1093                 return 0;
1094         }
1095
1096         if (!read_ref_full("HEAD", RESOLVE_REF_READING, oid.hash, &flag))
1097                 return fn("HEAD", &oid, flag, cb_data);
1098
1099         return 0;
1100 }
1101
1102 int head_ref(each_ref_fn fn, void *cb_data)
1103 {
1104         return head_ref_submodule(NULL, fn, cb_data);
1105 }
1106
1107 int for_each_ref(each_ref_fn fn, void *cb_data)
1108 {
1109         return do_for_each_ref(NULL, "", fn, 0, 0, cb_data);
1110 }
1111
1112 int for_each_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
1113 {
1114         return do_for_each_ref(submodule, "", fn, 0, 0, cb_data);
1115 }
1116
1117 int for_each_ref_in(const char *prefix, each_ref_fn fn, void *cb_data)
1118 {
1119         return do_for_each_ref(NULL, prefix, fn, strlen(prefix), 0, cb_data);
1120 }
1121
1122 int for_each_fullref_in(const char *prefix, each_ref_fn fn, void *cb_data, unsigned int broken)
1123 {
1124         unsigned int flag = 0;
1125
1126         if (broken)
1127                 flag = DO_FOR_EACH_INCLUDE_BROKEN;
1128         return do_for_each_ref(NULL, prefix, fn, 0, flag, cb_data);
1129 }
1130
1131 int for_each_ref_in_submodule(const char *submodule, const char *prefix,
1132                 each_ref_fn fn, void *cb_data)
1133 {
1134         return do_for_each_ref(submodule, prefix, fn, strlen(prefix), 0, cb_data);
1135 }
1136
1137 int for_each_replace_ref(each_ref_fn fn, void *cb_data)
1138 {
1139         return do_for_each_ref(NULL, git_replace_ref_base, fn,
1140                                strlen(git_replace_ref_base), 0, cb_data);
1141 }
1142
1143 int for_each_namespaced_ref(each_ref_fn fn, void *cb_data)
1144 {
1145         struct strbuf buf = STRBUF_INIT;
1146         int ret;
1147         strbuf_addf(&buf, "%srefs/", get_git_namespace());
1148         ret = do_for_each_ref(NULL, buf.buf, fn, 0, 0, cb_data);
1149         strbuf_release(&buf);
1150         return ret;
1151 }
1152
1153 int for_each_rawref(each_ref_fn fn, void *cb_data)
1154 {
1155         return do_for_each_ref(NULL, "", fn, 0,
1156                                DO_FOR_EACH_INCLUDE_BROKEN, cb_data);
1157 }
1158
1159 /* This function needs to return a meaningful errno on failure */
1160 const char *resolve_ref_unsafe(const char *refname, int resolve_flags,
1161                                unsigned char *sha1, int *flags)
1162 {
1163         static struct strbuf sb_refname = STRBUF_INIT;
1164         int unused_flags;
1165         int symref_count;
1166
1167         if (!flags)
1168                 flags = &unused_flags;
1169
1170         *flags = 0;
1171
1172         if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
1173                 if (!(resolve_flags & RESOLVE_REF_ALLOW_BAD_NAME) ||
1174                     !refname_is_safe(refname)) {
1175                         errno = EINVAL;
1176                         return NULL;
1177                 }
1178
1179                 /*
1180                  * dwim_ref() uses REF_ISBROKEN to distinguish between
1181                  * missing refs and refs that were present but invalid,
1182                  * to complain about the latter to stderr.
1183                  *
1184                  * We don't know whether the ref exists, so don't set
1185                  * REF_ISBROKEN yet.
1186                  */
1187                 *flags |= REF_BAD_NAME;
1188         }
1189
1190         for (symref_count = 0; symref_count < SYMREF_MAXDEPTH; symref_count++) {
1191                 unsigned int read_flags = 0;
1192
1193                 if (read_raw_ref(refname, sha1, &sb_refname, &read_flags)) {
1194                         *flags |= read_flags;
1195                         if (errno != ENOENT || (resolve_flags & RESOLVE_REF_READING))
1196                                 return NULL;
1197                         hashclr(sha1);
1198                         if (*flags & REF_BAD_NAME)
1199                                 *flags |= REF_ISBROKEN;
1200                         return refname;
1201                 }
1202
1203                 *flags |= read_flags;
1204
1205                 if (!(read_flags & REF_ISSYMREF)) {
1206                         if (*flags & REF_BAD_NAME) {
1207                                 hashclr(sha1);
1208                                 *flags |= REF_ISBROKEN;
1209                         }
1210                         return refname;
1211                 }
1212
1213                 refname = sb_refname.buf;
1214                 if (resolve_flags & RESOLVE_REF_NO_RECURSE) {
1215                         hashclr(sha1);
1216                         return refname;
1217                 }
1218                 if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
1219                         if (!(resolve_flags & RESOLVE_REF_ALLOW_BAD_NAME) ||
1220                             !refname_is_safe(refname)) {
1221                                 errno = EINVAL;
1222                                 return NULL;
1223                         }
1224
1225                         *flags |= REF_ISBROKEN | REF_BAD_NAME;
1226                 }
1227         }
1228
1229         errno = ELOOP;
1230         return NULL;
1231 }