6c8fe18581f0ed92c71419a2940e83c966331a7b
   1#include "cache.h"
   2#include "refs.h"
   3#include "object.h"
   4#include "tag.h"
   5#include "dir.h"
   6
   7/*
   8 * Make sure "ref" is something reasonable to have under ".git/refs/";
   9 * We do not like it if:
  10 *
  11 * - any path component of it begins with ".", or
  12 * - it has double dots "..", or
  13 * - it has ASCII control character, "~", "^", ":" or SP, anywhere, or
  14 * - it ends with a "/".
  15 * - it ends with ".lock"
  16 * - it contains a "\" (backslash)
  17 */
  18
  19/* Return true iff ch is not allowed in reference names. */
  20static inline int bad_ref_char(int ch)
  21{
  22        if (((unsigned) ch) <= ' ' || ch == 0x7f ||
  23            ch == '~' || ch == '^' || ch == ':' || ch == '\\')
  24                return 1;
  25        /* 2.13 Pattern Matching Notation */
  26        if (ch == '*' || ch == '?' || ch == '[') /* Unsupported */
  27                return 1;
  28        return 0;
  29}
  30
  31/*
  32 * Try to read one refname component from the front of refname.  Return
  33 * the length of the component found, or -1 if the component is not
  34 * legal.
  35 */
  36static int check_refname_component(const char *refname, int flags)
  37{
  38        const char *cp;
  39        char last = '\0';
  40
  41        for (cp = refname; ; cp++) {
  42                char ch = *cp;
  43                if (ch == '\0' || ch == '/')
  44                        break;
  45                if (bad_ref_char(ch))
  46                        return -1; /* Illegal character in refname. */
  47                if (last == '.' && ch == '.')
  48                        return -1; /* Refname contains "..". */
  49                if (last == '@' && ch == '{')
  50                        return -1; /* Refname contains "@{". */
  51                last = ch;
  52        }
  53        if (cp == refname)
  54                return 0; /* Component has zero length. */
  55        if (refname[0] == '.') {
  56                if (!(flags & REFNAME_DOT_COMPONENT))
  57                        return -1; /* Component starts with '.'. */
  58                /*
  59                 * Even if leading dots are allowed, don't allow "."
  60                 * as a component (".." is prevented by a rule above).
  61                 */
  62                if (refname[1] == '\0')
  63                        return -1; /* Component equals ".". */
  64        }
  65        if (cp - refname >= 5 && !memcmp(cp - 5, ".lock", 5))
  66                return -1; /* Refname ends with ".lock". */
  67        return cp - refname;
  68}
  69
  70int check_refname_format(const char *refname, int flags)
  71{
  72        int component_len, component_count = 0;
  73
  74        while (1) {
  75                /* We are at the start of a path component. */
  76                component_len = check_refname_component(refname, flags);
  77                if (component_len <= 0) {
  78                        if ((flags & REFNAME_REFSPEC_PATTERN) &&
  79                                        refname[0] == '*' &&
  80                                        (refname[1] == '\0' || refname[1] == '/')) {
  81                                /* Accept one wildcard as a full refname component. */
  82                                flags &= ~REFNAME_REFSPEC_PATTERN;
  83                                component_len = 1;
  84                        } else {
  85                                return -1;
  86                        }
  87                }
  88                component_count++;
  89                if (refname[component_len] == '\0')
  90                        break;
  91                /* Skip to next component. */
  92                refname += component_len + 1;
  93        }
  94
  95        if (refname[component_len - 1] == '.')
  96                return -1; /* Refname ends with '.'. */
  97        if (!(flags & REFNAME_ALLOW_ONELEVEL) && component_count < 2)
  98                return -1; /* Refname has only one component. */
  99        return 0;
 100}
 101
 102struct ref_entry;
 103
 104/*
 105 * Information used (along with the information in ref_entry) to
 106 * describe a single cached reference.  This data structure only
 107 * occurs embedded in a union in struct ref_entry, and only when
 108 * (ref_entry->flag & REF_DIR) is zero.
 109 */
 110struct ref_value {
 111        /*
 112         * The name of the object to which this reference resolves
 113         * (which may be a tag object).  If REF_ISBROKEN, this is
 114         * null.  If REF_ISSYMREF, then this is the name of the object
 115         * referred to by the last reference in the symlink chain.
 116         */
 117        unsigned char sha1[20];
 118
 119        /*
 120         * If REF_KNOWS_PEELED, then this field holds the peeled value
 121         * of this reference, or null if the reference is known not to
 122         * be peelable.
 123         */
 124        unsigned char peeled[20];
 125};
 126
 127struct ref_cache;
 128
 129/*
 130 * Information used (along with the information in ref_entry) to
 131 * describe a level in the hierarchy of references.  This data
 132 * structure only occurs embedded in a union in struct ref_entry, and
 133 * only when (ref_entry.flag & REF_DIR) is set.  In that case,
 134 * (ref_entry.flag & REF_INCOMPLETE) determines whether the references
 135 * in the directory have already been read:
 136 *
 137 *     (ref_entry.flag & REF_INCOMPLETE) unset -- a directory of loose
 138 *         or packed references, already read.
 139 *
 140 *     (ref_entry.flag & REF_INCOMPLETE) set -- a directory of loose
 141 *         references that hasn't been read yet (nor has any of its
 142 *         subdirectories).
 143 *
 144 * Entries within a directory are stored within a growable array of
 145 * pointers to ref_entries (entries, nr, alloc).  Entries 0 <= i <
 146 * sorted are sorted by their component name in strcmp() order and the
 147 * remaining entries are unsorted.
 148 *
 149 * Loose references are read lazily, one directory at a time.  When a
 150 * directory of loose references is read, then all of the references
 151 * in that directory are stored, and REF_INCOMPLETE stubs are created
 152 * for any subdirectories, but the subdirectories themselves are not
 153 * read.  The reading is triggered by get_ref_dir().
 154 */
 155struct ref_dir {
 156        int nr, alloc;
 157
 158        /*
 159         * Entries with index 0 <= i < sorted are sorted by name.  New
 160         * entries are appended to the list unsorted, and are sorted
 161         * only when required; thus we avoid the need to sort the list
 162         * after the addition of every reference.
 163         */
 164        int sorted;
 165
 166        /* A pointer to the ref_cache that contains this ref_dir. */
 167        struct ref_cache *ref_cache;
 168
 169        struct ref_entry **entries;
 170};
 171
 172/*
 173 * Bit values for ref_entry::flag.  REF_ISSYMREF=0x01,
 174 * REF_ISPACKED=0x02, and REF_ISBROKEN=0x04 are public values; see
 175 * refs.h.
 176 */
 177
 178/*
 179 * The field ref_entry->u.value.peeled of this value entry contains
 180 * the correct peeled value for the reference, which might be
 181 * null_sha1 if the reference is not a tag or if it is broken.
 182 */
 183#define REF_KNOWS_PEELED 0x08
 184
 185/* ref_entry represents a directory of references */
 186#define REF_DIR 0x10
 187
 188/*
 189 * Entry has not yet been read from disk (used only for REF_DIR
 190 * entries representing loose references)
 191 */
 192#define REF_INCOMPLETE 0x20
 193
 194/*
 195 * A ref_entry represents either a reference or a "subdirectory" of
 196 * references.
 197 *
 198 * Each directory in the reference namespace is represented by a
 199 * ref_entry with (flags & REF_DIR) set and containing a subdir member
 200 * that holds the entries in that directory that have been read so
 201 * far.  If (flags & REF_INCOMPLETE) is set, then the directory and
 202 * its subdirectories haven't been read yet.  REF_INCOMPLETE is only
 203 * used for loose reference directories.
 204 *
 205 * References are represented by a ref_entry with (flags & REF_DIR)
 206 * unset and a value member that describes the reference's value.  The
 207 * flag member is at the ref_entry level, but it is also needed to
 208 * interpret the contents of the value field (in other words, a
 209 * ref_value object is not very much use without the enclosing
 210 * ref_entry).
 211 *
 212 * Reference names cannot end with slash and directories' names are
 213 * always stored with a trailing slash (except for the top-level
 214 * directory, which is always denoted by "").  This has two nice
 215 * consequences: (1) when the entries in each subdir are sorted
 216 * lexicographically by name (as they usually are), the references in
 217 * a whole tree can be generated in lexicographic order by traversing
 218 * the tree in left-to-right, depth-first order; (2) the names of
 219 * references and subdirectories cannot conflict, and therefore the
 220 * presence of an empty subdirectory does not block the creation of a
 221 * similarly-named reference.  (The fact that reference names with the
 222 * same leading components can conflict *with each other* is a
 223 * separate issue that is regulated by is_refname_available().)
 224 *
 225 * Please note that the name field contains the fully-qualified
 226 * reference (or subdirectory) name.  Space could be saved by only
 227 * storing the relative names.  But that would require the full names
 228 * to be generated on the fly when iterating in do_for_each_ref(), and
 229 * would break callback functions, who have always been able to assume
 230 * that the name strings that they are passed will not be freed during
 231 * the iteration.
 232 */
 233struct ref_entry {
 234        unsigned char flag; /* ISSYMREF? ISPACKED? */
 235        union {
 236                struct ref_value value; /* if not (flags&REF_DIR) */
 237                struct ref_dir subdir; /* if (flags&REF_DIR) */
 238        } u;
 239        /*
 240         * The full name of the reference (e.g., "refs/heads/master")
 241         * or the full name of the directory with a trailing slash
 242         * (e.g., "refs/heads/"):
 243         */
 244        char name[FLEX_ARRAY];
 245};
 246
 247static void read_loose_refs(const char *dirname, struct ref_dir *dir);
 248
 249static struct ref_dir *get_ref_dir(struct ref_entry *entry)
 250{
 251        struct ref_dir *dir;
 252        assert(entry->flag & REF_DIR);
 253        dir = &entry->u.subdir;
 254        if (entry->flag & REF_INCOMPLETE) {
 255                read_loose_refs(entry->name, dir);
 256                entry->flag &= ~REF_INCOMPLETE;
 257        }
 258        return dir;
 259}
 260
 261static struct ref_entry *create_ref_entry(const char *refname,
 262                                          const unsigned char *sha1, int flag,
 263                                          int check_name)
 264{
 265        int len;
 266        struct ref_entry *ref;
 267
 268        if (check_name &&
 269            check_refname_format(refname, REFNAME_ALLOW_ONELEVEL|REFNAME_DOT_COMPONENT))
 270                die("Reference has invalid format: '%s'", refname);
 271        len = strlen(refname) + 1;
 272        ref = xmalloc(sizeof(struct ref_entry) + len);
 273        hashcpy(ref->u.value.sha1, sha1);
 274        hashclr(ref->u.value.peeled);
 275        memcpy(ref->name, refname, len);
 276        ref->flag = flag;
 277        return ref;
 278}
 279
 280static void clear_ref_dir(struct ref_dir *dir);
 281
 282static void free_ref_entry(struct ref_entry *entry)
 283{
 284        if (entry->flag & REF_DIR) {
 285                /*
 286                 * Do not use get_ref_dir() here, as that might
 287                 * trigger the reading of loose refs.
 288                 */
 289                clear_ref_dir(&entry->u.subdir);
 290        }
 291        free(entry);
 292}
 293
 294/*
 295 * Add a ref_entry to the end of dir (unsorted).  Entry is always
 296 * stored directly in dir; no recursion into subdirectories is
 297 * done.
 298 */
 299static void add_entry_to_dir(struct ref_dir *dir, struct ref_entry *entry)
 300{
 301        ALLOC_GROW(dir->entries, dir->nr + 1, dir->alloc);
 302        dir->entries[dir->nr++] = entry;
 303        /* optimize for the case that entries are added in order */
 304        if (dir->nr == 1 ||
 305            (dir->nr == dir->sorted + 1 &&
 306             strcmp(dir->entries[dir->nr - 2]->name,
 307                    dir->entries[dir->nr - 1]->name) < 0))
 308                dir->sorted = dir->nr;
 309}
 310
 311/*
 312 * Clear and free all entries in dir, recursively.
 313 */
 314static void clear_ref_dir(struct ref_dir *dir)
 315{
 316        int i;
 317        for (i = 0; i < dir->nr; i++)
 318                free_ref_entry(dir->entries[i]);
 319        free(dir->entries);
 320        dir->sorted = dir->nr = dir->alloc = 0;
 321        dir->entries = NULL;
 322}
 323
 324/*
 325 * Create a struct ref_entry object for the specified dirname.
 326 * dirname is the name of the directory with a trailing slash (e.g.,
 327 * "refs/heads/") or "" for the top-level directory.
 328 */
 329static struct ref_entry *create_dir_entry(struct ref_cache *ref_cache,
 330                                          const char *dirname, size_t len,
 331                                          int incomplete)
 332{
 333        struct ref_entry *direntry;
 334        direntry = xcalloc(1, sizeof(struct ref_entry) + len + 1);
 335        memcpy(direntry->name, dirname, len);
 336        direntry->name[len] = '\0';
 337        direntry->u.subdir.ref_cache = ref_cache;
 338        direntry->flag = REF_DIR | (incomplete ? REF_INCOMPLETE : 0);
 339        return direntry;
 340}
 341
 342static int ref_entry_cmp(const void *a, const void *b)
 343{
 344        struct ref_entry *one = *(struct ref_entry **)a;
 345        struct ref_entry *two = *(struct ref_entry **)b;
 346        return strcmp(one->name, two->name);
 347}
 348
 349static void sort_ref_dir(struct ref_dir *dir);
 350
 351struct string_slice {
 352        size_t len;
 353        const char *str;
 354};
 355
 356static int ref_entry_cmp_sslice(const void *key_, const void *ent_)
 357{
 358        struct string_slice *key = (struct string_slice *)key_;
 359        struct ref_entry *ent = *(struct ref_entry **)ent_;
 360        int entlen = strlen(ent->name);
 361        int cmplen = key->len < entlen ? key->len : entlen;
 362        int cmp = memcmp(key->str, ent->name, cmplen);
 363        if (cmp)
 364                return cmp;
 365        return key->len - entlen;
 366}
 367
 368/*
 369 * Return the entry with the given refname from the ref_dir
 370 * (non-recursively), sorting dir if necessary.  Return NULL if no
 371 * such entry is found.  dir must already be complete.
 372 */
 373static struct ref_entry *search_ref_dir(struct ref_dir *dir,
 374                                        const char *refname, size_t len)
 375{
 376        struct ref_entry **r;
 377        struct string_slice key;
 378
 379        if (refname == NULL || !dir->nr)
 380                return NULL;
 381
 382        sort_ref_dir(dir);
 383        key.len = len;
 384        key.str = refname;
 385        r = bsearch(&key, dir->entries, dir->nr, sizeof(*dir->entries),
 386                    ref_entry_cmp_sslice);
 387
 388        if (r == NULL)
 389                return NULL;
 390
 391        return *r;
 392}
 393
 394/*
 395 * Search for a directory entry directly within dir (without
 396 * recursing).  Sort dir if necessary.  subdirname must be a directory
 397 * name (i.e., end in '/').  If mkdir is set, then create the
 398 * directory if it is missing; otherwise, return NULL if the desired
 399 * directory cannot be found.  dir must already be complete.
 400 */
 401static struct ref_dir *search_for_subdir(struct ref_dir *dir,
 402                                         const char *subdirname, size_t len,
 403                                         int mkdir)
 404{
 405        struct ref_entry *entry = search_ref_dir(dir, subdirname, len);
 406        if (!entry) {
 407                if (!mkdir)
 408                        return NULL;
 409                /*
 410                 * Since dir is complete, the absence of a subdir
 411                 * means that the subdir really doesn't exist;
 412                 * therefore, create an empty record for it but mark
 413                 * the record complete.
 414                 */
 415                entry = create_dir_entry(dir->ref_cache, subdirname, len, 0);
 416                add_entry_to_dir(dir, entry);
 417        }
 418        return get_ref_dir(entry);
 419}
 420
 421/*
 422 * If refname is a reference name, find the ref_dir within the dir
 423 * tree that should hold refname.  If refname is a directory name
 424 * (i.e., ends in '/'), then return that ref_dir itself.  dir must
 425 * represent the top-level directory and must already be complete.
 426 * Sort ref_dirs and recurse into subdirectories as necessary.  If
 427 * mkdir is set, then create any missing directories; otherwise,
 428 * return NULL if the desired directory cannot be found.
 429 */
 430static struct ref_dir *find_containing_dir(struct ref_dir *dir,
 431                                           const char *refname, int mkdir)
 432{
 433        const char *slash;
 434        for (slash = strchr(refname, '/'); slash; slash = strchr(slash + 1, '/')) {
 435                size_t dirnamelen = slash - refname + 1;
 436                struct ref_dir *subdir;
 437                subdir = search_for_subdir(dir, refname, dirnamelen, mkdir);
 438                if (!subdir) {
 439                        dir = NULL;
 440                        break;
 441                }
 442                dir = subdir;
 443        }
 444
 445        return dir;
 446}
 447
 448/*
 449 * Find the value entry with the given name in dir, sorting ref_dirs
 450 * and recursing into subdirectories as necessary.  If the name is not
 451 * found or it corresponds to a directory entry, return NULL.
 452 */
 453static struct ref_entry *find_ref(struct ref_dir *dir, const char *refname)
 454{
 455        struct ref_entry *entry;
 456        dir = find_containing_dir(dir, refname, 0);
 457        if (!dir)
 458                return NULL;
 459        entry = search_ref_dir(dir, refname, strlen(refname));
 460        return (entry && !(entry->flag & REF_DIR)) ? entry : NULL;
 461}
 462
 463/*
 464 * Add a ref_entry to the ref_dir (unsorted), recursing into
 465 * subdirectories as necessary.  dir must represent the top-level
 466 * directory.  Return 0 on success.
 467 */
 468static int add_ref(struct ref_dir *dir, struct ref_entry *ref)
 469{
 470        dir = find_containing_dir(dir, ref->name, 1);
 471        if (!dir)
 472                return -1;
 473        add_entry_to_dir(dir, ref);
 474        return 0;
 475}
 476
 477/*
 478 * Emit a warning and return true iff ref1 and ref2 have the same name
 479 * and the same sha1.  Die if they have the same name but different
 480 * sha1s.
 481 */
 482static int is_dup_ref(const struct ref_entry *ref1, const struct ref_entry *ref2)
 483{
 484        if (strcmp(ref1->name, ref2->name))
 485                return 0;
 486
 487        /* Duplicate name; make sure that they don't conflict: */
 488
 489        if ((ref1->flag & REF_DIR) || (ref2->flag & REF_DIR))
 490                /* This is impossible by construction */
 491                die("Reference directory conflict: %s", ref1->name);
 492
 493        if (hashcmp(ref1->u.value.sha1, ref2->u.value.sha1))
 494                die("Duplicated ref, and SHA1s don't match: %s", ref1->name);
 495
 496        warning("Duplicated ref: %s", ref1->name);
 497        return 1;
 498}
 499
 500/*
 501 * Sort the entries in dir non-recursively (if they are not already
 502 * sorted) and remove any duplicate entries.
 503 */
 504static void sort_ref_dir(struct ref_dir *dir)
 505{
 506        int i, j;
 507        struct ref_entry *last = NULL;
 508
 509        /*
 510         * This check also prevents passing a zero-length array to qsort(),
 511         * which is a problem on some platforms.
 512         */
 513        if (dir->sorted == dir->nr)
 514                return;
 515
 516        qsort(dir->entries, dir->nr, sizeof(*dir->entries), ref_entry_cmp);
 517
 518        /* Remove any duplicates: */
 519        for (i = 0, j = 0; j < dir->nr; j++) {
 520                struct ref_entry *entry = dir->entries[j];
 521                if (last && is_dup_ref(last, entry))
 522                        free_ref_entry(entry);
 523                else
 524                        last = dir->entries[i++] = entry;
 525        }
 526        dir->sorted = dir->nr = i;
 527}
 528
 529/* Include broken references in a do_for_each_ref*() iteration: */
 530#define DO_FOR_EACH_INCLUDE_BROKEN 0x01
 531
 532static struct ref_entry *current_ref;
 533
 534/*
 535 * Handle one reference in a do_for_each_ref*()-style iteration.
 536 */
 537static int do_one_ref(const char *base, each_ref_fn fn, int trim,
 538                      int flags, void *cb_data, struct ref_entry *entry)
 539{
 540        int retval;
 541        if (prefixcmp(entry->name, base))
 542                return 0;
 543
 544        if (!(flags & DO_FOR_EACH_INCLUDE_BROKEN)) {
 545                if (entry->flag & REF_ISBROKEN)
 546                        return 0; /* ignore broken refs e.g. dangling symref */
 547                if (!has_sha1_file(entry->u.value.sha1)) {
 548                        error("%s does not point to a valid object!", entry->name);
 549                        return 0;
 550                }
 551        }
 552        current_ref = entry;
 553        retval = fn(entry->name + trim, entry->u.value.sha1, entry->flag, cb_data);
 554        current_ref = NULL;
 555        return retval;
 556}
 557
 558/*
 559 * Call fn for each reference in dir that has index in the range
 560 * offset <= index < dir->nr.  Recurse into subdirectories that are in
 561 * that index range, sorting them before iterating.  This function
 562 * does not sort dir itself; it should be sorted beforehand.
 563 */
 564static int do_for_each_ref_in_dir(struct ref_dir *dir, int offset,
 565                                  const char *base,
 566                                  each_ref_fn fn, int trim, int flags, void *cb_data)
 567{
 568        int i;
 569        assert(dir->sorted == dir->nr);
 570        for (i = offset; i < dir->nr; i++) {
 571                struct ref_entry *entry = dir->entries[i];
 572                int retval;
 573                if (entry->flag & REF_DIR) {
 574                        struct ref_dir *subdir = get_ref_dir(entry);
 575                        sort_ref_dir(subdir);
 576                        retval = do_for_each_ref_in_dir(subdir, 0,
 577                                                        base, fn, trim, flags, cb_data);
 578                } else {
 579                        retval = do_one_ref(base, fn, trim, flags, cb_data, entry);
 580                }
 581                if (retval)
 582                        return retval;
 583        }
 584        return 0;
 585}
 586
 587/*
 588 * Call fn for each reference in the union of dir1 and dir2, in order
 589 * by refname.  Recurse into subdirectories.  If a value entry appears
 590 * in both dir1 and dir2, then only process the version that is in
 591 * dir2.  The input dirs must already be sorted, but subdirs will be
 592 * sorted as needed.
 593 */
 594static int do_for_each_ref_in_dirs(struct ref_dir *dir1,
 595                                   struct ref_dir *dir2,
 596                                   const char *base, each_ref_fn fn, int trim,
 597                                   int flags, void *cb_data)
 598{
 599        int retval;
 600        int i1 = 0, i2 = 0;
 601
 602        assert(dir1->sorted == dir1->nr);
 603        assert(dir2->sorted == dir2->nr);
 604        while (1) {
 605                struct ref_entry *e1, *e2;
 606                int cmp;
 607                if (i1 == dir1->nr) {
 608                        return do_for_each_ref_in_dir(dir2, i2,
 609                                                      base, fn, trim, flags, cb_data);
 610                }
 611                if (i2 == dir2->nr) {
 612                        return do_for_each_ref_in_dir(dir1, i1,
 613                                                      base, fn, trim, flags, cb_data);
 614                }
 615                e1 = dir1->entries[i1];
 616                e2 = dir2->entries[i2];
 617                cmp = strcmp(e1->name, e2->name);
 618                if (cmp == 0) {
 619                        if ((e1->flag & REF_DIR) && (e2->flag & REF_DIR)) {
 620                                /* Both are directories; descend them in parallel. */
 621                                struct ref_dir *subdir1 = get_ref_dir(e1);
 622                                struct ref_dir *subdir2 = get_ref_dir(e2);
 623                                sort_ref_dir(subdir1);
 624                                sort_ref_dir(subdir2);
 625                                retval = do_for_each_ref_in_dirs(
 626                                                subdir1, subdir2,
 627                                                base, fn, trim, flags, cb_data);
 628                                i1++;
 629                                i2++;
 630                        } else if (!(e1->flag & REF_DIR) && !(e2->flag & REF_DIR)) {
 631                                /* Both are references; ignore the one from dir1. */
 632                                retval = do_one_ref(base, fn, trim, flags, cb_data, e2);
 633                                i1++;
 634                                i2++;
 635                        } else {
 636                                die("conflict between reference and directory: %s",
 637                                    e1->name);
 638                        }
 639                } else {
 640                        struct ref_entry *e;
 641                        if (cmp < 0) {
 642                                e = e1;
 643                                i1++;
 644                        } else {
 645                                e = e2;
 646                                i2++;
 647                        }
 648                        if (e->flag & REF_DIR) {
 649                                struct ref_dir *subdir = get_ref_dir(e);
 650                                sort_ref_dir(subdir);
 651                                retval = do_for_each_ref_in_dir(
 652                                                subdir, 0,
 653                                                base, fn, trim, flags, cb_data);
 654                        } else {
 655                                retval = do_one_ref(base, fn, trim, flags, cb_data, e);
 656                        }
 657                }
 658                if (retval)
 659                        return retval;
 660        }
 661        if (i1 < dir1->nr)
 662                return do_for_each_ref_in_dir(dir1, i1,
 663                                              base, fn, trim, flags, cb_data);
 664        if (i2 < dir2->nr)
 665                return do_for_each_ref_in_dir(dir2, i2,
 666                                              base, fn, trim, flags, cb_data);
 667        return 0;
 668}
 669
 670/*
 671 * Return true iff refname1 and refname2 conflict with each other.
 672 * Two reference names conflict if one of them exactly matches the
 673 * leading components of the other; e.g., "foo/bar" conflicts with
 674 * both "foo" and with "foo/bar/baz" but not with "foo/bar" or
 675 * "foo/barbados".
 676 */
 677static int names_conflict(const char *refname1, const char *refname2)
 678{
 679        for (; *refname1 && *refname1 == *refname2; refname1++, refname2++)
 680                ;
 681        return (*refname1 == '\0' && *refname2 == '/')
 682                || (*refname1 == '/' && *refname2 == '\0');
 683}
 684
 685struct name_conflict_cb {
 686        const char *refname;
 687        const char *oldrefname;
 688        const char *conflicting_refname;
 689};
 690
 691static int name_conflict_fn(const char *existingrefname, const unsigned char *sha1,
 692                            int flags, void *cb_data)
 693{
 694        struct name_conflict_cb *data = (struct name_conflict_cb *)cb_data;
 695        if (data->oldrefname && !strcmp(data->oldrefname, existingrefname))
 696                return 0;
 697        if (names_conflict(data->refname, existingrefname)) {
 698                data->conflicting_refname = existingrefname;
 699                return 1;
 700        }
 701        return 0;
 702}
 703
 704/*
 705 * Return true iff a reference named refname could be created without
 706 * conflicting with the name of an existing reference in array.  If
 707 * oldrefname is non-NULL, ignore potential conflicts with oldrefname
 708 * (e.g., because oldrefname is scheduled for deletion in the same
 709 * operation).
 710 */
 711static int is_refname_available(const char *refname, const char *oldrefname,
 712                                struct ref_dir *dir)
 713{
 714        struct name_conflict_cb data;
 715        data.refname = refname;
 716        data.oldrefname = oldrefname;
 717        data.conflicting_refname = NULL;
 718
 719        sort_ref_dir(dir);
 720        if (do_for_each_ref_in_dir(dir, 0, "", name_conflict_fn,
 721                                   0, DO_FOR_EACH_INCLUDE_BROKEN,
 722                                   &data)) {
 723                error("'%s' exists; cannot create '%s'",
 724                      data.conflicting_refname, refname);
 725                return 0;
 726        }
 727        return 1;
 728}
 729
 730/*
 731 * Future: need to be in "struct repository"
 732 * when doing a full libification.
 733 */
 734static struct ref_cache {
 735        struct ref_cache *next;
 736        struct ref_entry *loose;
 737        struct ref_entry *packed;
 738        /* The submodule name, or "" for the main repo. */
 739        char name[FLEX_ARRAY];
 740} *ref_cache;
 741
 742static void clear_packed_ref_cache(struct ref_cache *refs)
 743{
 744        if (refs->packed) {
 745                free_ref_entry(refs->packed);
 746                refs->packed = NULL;
 747        }
 748}
 749
 750static void clear_loose_ref_cache(struct ref_cache *refs)
 751{
 752        if (refs->loose) {
 753                free_ref_entry(refs->loose);
 754                refs->loose = NULL;
 755        }
 756}
 757
 758static struct ref_cache *create_ref_cache(const char *submodule)
 759{
 760        int len;
 761        struct ref_cache *refs;
 762        if (!submodule)
 763                submodule = "";
 764        len = strlen(submodule) + 1;
 765        refs = xcalloc(1, sizeof(struct ref_cache) + len);
 766        memcpy(refs->name, submodule, len);
 767        return refs;
 768}
 769
 770/*
 771 * Return a pointer to a ref_cache for the specified submodule. For
 772 * the main repository, use submodule==NULL. The returned structure
 773 * will be allocated and initialized but not necessarily populated; it
 774 * should not be freed.
 775 */
 776static struct ref_cache *get_ref_cache(const char *submodule)
 777{
 778        struct ref_cache *refs = ref_cache;
 779        if (!submodule)
 780                submodule = "";
 781        while (refs) {
 782                if (!strcmp(submodule, refs->name))
 783                        return refs;
 784                refs = refs->next;
 785        }
 786
 787        refs = create_ref_cache(submodule);
 788        refs->next = ref_cache;
 789        ref_cache = refs;
 790        return refs;
 791}
 792
 793void invalidate_ref_cache(const char *submodule)
 794{
 795        struct ref_cache *refs = get_ref_cache(submodule);
 796        clear_packed_ref_cache(refs);
 797        clear_loose_ref_cache(refs);
 798}
 799
 800/*
 801 * Parse one line from a packed-refs file.  Write the SHA1 to sha1.
 802 * Return a pointer to the refname within the line (null-terminated),
 803 * or NULL if there was a problem.
 804 */
 805static const char *parse_ref_line(char *line, unsigned char *sha1)
 806{
 807        /*
 808         * 42: the answer to everything.
 809         *
 810         * In this case, it happens to be the answer to
 811         *  40 (length of sha1 hex representation)
 812         *  +1 (space in between hex and name)
 813         *  +1 (newline at the end of the line)
 814         */
 815        int len = strlen(line) - 42;
 816
 817        if (len <= 0)
 818                return NULL;
 819        if (get_sha1_hex(line, sha1) < 0)
 820                return NULL;
 821        if (!isspace(line[40]))
 822                return NULL;
 823        line += 41;
 824        if (isspace(*line))
 825                return NULL;
 826        if (line[len] != '\n')
 827                return NULL;
 828        line[len] = 0;
 829
 830        return line;
 831}
 832
 833/*
 834 * Read f, which is a packed-refs file, into dir.
 835 *
 836 * A comment line of the form "# pack-refs with: " may contain zero or
 837 * more traits. We interpret the traits as follows:
 838 *
 839 *   No traits:
 840 *
 841 *      Probably no references are peeled. But if the file contains a
 842 *      peeled value for a reference, we will use it.
 843 *
 844 *   peeled:
 845 *
 846 *      References under "refs/tags/", if they *can* be peeled, *are*
 847 *      peeled in this file. References outside of "refs/tags/" are
 848 *      probably not peeled even if they could have been, but if we find
 849 *      a peeled value for such a reference we will use it.
 850 *
 851 *   fully-peeled:
 852 *
 853 *      All references in the file that can be peeled are peeled.
 854 *      Inversely (and this is more important), any references in the
 855 *      file for which no peeled value is recorded is not peelable. This
 856 *      trait should typically be written alongside "peeled" for
 857 *      compatibility with older clients, but we do not require it
 858 *      (i.e., "peeled" is a no-op if "fully-peeled" is set).
 859 */
 860static void read_packed_refs(FILE *f, struct ref_dir *dir)
 861{
 862        struct ref_entry *last = NULL;
 863        char refline[PATH_MAX];
 864        enum { PEELED_NONE, PEELED_TAGS, PEELED_FULLY } peeled = PEELED_NONE;
 865
 866        while (fgets(refline, sizeof(refline), f)) {
 867                unsigned char sha1[20];
 868                const char *refname;
 869                static const char header[] = "# pack-refs with:";
 870
 871                if (!strncmp(refline, header, sizeof(header)-1)) {
 872                        const char *traits = refline + sizeof(header) - 1;
 873                        if (strstr(traits, " fully-peeled "))
 874                                peeled = PEELED_FULLY;
 875                        else if (strstr(traits, " peeled "))
 876                                peeled = PEELED_TAGS;
 877                        /* perhaps other traits later as well */
 878                        continue;
 879                }
 880
 881                refname = parse_ref_line(refline, sha1);
 882                if (refname) {
 883                        last = create_ref_entry(refname, sha1, REF_ISPACKED, 1);
 884                        if (peeled == PEELED_FULLY ||
 885                            (peeled == PEELED_TAGS && !prefixcmp(refname, "refs/tags/")))
 886                                last->flag |= REF_KNOWS_PEELED;
 887                        add_ref(dir, last);
 888                        continue;
 889                }
 890                if (last &&
 891                    refline[0] == '^' &&
 892                    strlen(refline) == 42 &&
 893                    refline[41] == '\n' &&
 894                    !get_sha1_hex(refline + 1, sha1)) {
 895                        hashcpy(last->u.value.peeled, sha1);
 896                        /*
 897                         * Regardless of what the file header said,
 898                         * we definitely know the value of *this*
 899                         * reference:
 900                         */
 901                        last->flag |= REF_KNOWS_PEELED;
 902                }
 903        }
 904}
 905
 906static struct ref_dir *get_packed_refs(struct ref_cache *refs)
 907{
 908        if (!refs->packed) {
 909                const char *packed_refs_file;
 910                FILE *f;
 911
 912                refs->packed = create_dir_entry(refs, "", 0, 0);
 913                if (*refs->name)
 914                        packed_refs_file = git_path_submodule(refs->name, "packed-refs");
 915                else
 916                        packed_refs_file = git_path("packed-refs");
 917                f = fopen(packed_refs_file, "r");
 918                if (f) {
 919                        read_packed_refs(f, get_ref_dir(refs->packed));
 920                        fclose(f);
 921                }
 922        }
 923        return get_ref_dir(refs->packed);
 924}
 925
 926void add_packed_ref(const char *refname, const unsigned char *sha1)
 927{
 928        add_ref(get_packed_refs(get_ref_cache(NULL)),
 929                        create_ref_entry(refname, sha1, REF_ISPACKED, 1));
 930}
 931
 932/*
 933 * Read the loose references from the namespace dirname into dir
 934 * (without recursing).  dirname must end with '/'.  dir must be the
 935 * directory entry corresponding to dirname.
 936 */
 937static void read_loose_refs(const char *dirname, struct ref_dir *dir)
 938{
 939        struct ref_cache *refs = dir->ref_cache;
 940        DIR *d;
 941        const char *path;
 942        struct dirent *de;
 943        int dirnamelen = strlen(dirname);
 944        struct strbuf refname;
 945
 946        if (*refs->name)
 947                path = git_path_submodule(refs->name, "%s", dirname);
 948        else
 949                path = git_path("%s", dirname);
 950
 951        d = opendir(path);
 952        if (!d)
 953                return;
 954
 955        strbuf_init(&refname, dirnamelen + 257);
 956        strbuf_add(&refname, dirname, dirnamelen);
 957
 958        while ((de = readdir(d)) != NULL) {
 959                unsigned char sha1[20];
 960                struct stat st;
 961                int flag;
 962                const char *refdir;
 963
 964                if (de->d_name[0] == '.')
 965                        continue;
 966                if (has_extension(de->d_name, ".lock"))
 967                        continue;
 968                strbuf_addstr(&refname, de->d_name);
 969                refdir = *refs->name
 970                        ? git_path_submodule(refs->name, "%s", refname.buf)
 971                        : git_path("%s", refname.buf);
 972                if (stat(refdir, &st) < 0) {
 973                        ; /* silently ignore */
 974                } else if (S_ISDIR(st.st_mode)) {
 975                        strbuf_addch(&refname, '/');
 976                        add_entry_to_dir(dir,
 977                                         create_dir_entry(refs, refname.buf,
 978                                                          refname.len, 1));
 979                } else {
 980                        if (*refs->name) {
 981                                hashclr(sha1);
 982                                flag = 0;
 983                                if (resolve_gitlink_ref(refs->name, refname.buf, sha1) < 0) {
 984                                        hashclr(sha1);
 985                                        flag |= REF_ISBROKEN;
 986                                }
 987                        } else if (read_ref_full(refname.buf, sha1, 1, &flag)) {
 988                                hashclr(sha1);
 989                                flag |= REF_ISBROKEN;
 990                        }
 991                        add_entry_to_dir(dir,
 992                                         create_ref_entry(refname.buf, sha1, flag, 1));
 993                }
 994                strbuf_setlen(&refname, dirnamelen);
 995        }
 996        strbuf_release(&refname);
 997        closedir(d);
 998}
 999
1000static struct ref_dir *get_loose_refs(struct ref_cache *refs)
1001{
1002        if (!refs->loose) {
1003                /*
1004                 * Mark the top-level directory complete because we
1005                 * are about to read the only subdirectory that can
1006                 * hold references:
1007                 */
1008                refs->loose = create_dir_entry(refs, "", 0, 0);
1009                /*
1010                 * Create an incomplete entry for "refs/":
1011                 */
1012                add_entry_to_dir(get_ref_dir(refs->loose),
1013                                 create_dir_entry(refs, "refs/", 5, 1));
1014        }
1015        return get_ref_dir(refs->loose);
1016}
1017
1018/* We allow "recursive" symbolic refs. Only within reason, though */
1019#define MAXDEPTH 5
1020#define MAXREFLEN (1024)
1021
1022/*
1023 * Called by resolve_gitlink_ref_recursive() after it failed to read
1024 * from the loose refs in ref_cache refs. Find <refname> in the
1025 * packed-refs file for the submodule.
1026 */
1027static int resolve_gitlink_packed_ref(struct ref_cache *refs,
1028                                      const char *refname, unsigned char *sha1)
1029{
1030        struct ref_entry *ref;
1031        struct ref_dir *dir = get_packed_refs(refs);
1032
1033        ref = find_ref(dir, refname);
1034        if (ref == NULL)
1035                return -1;
1036
1037        memcpy(sha1, ref->u.value.sha1, 20);
1038        return 0;
1039}
1040
1041static int resolve_gitlink_ref_recursive(struct ref_cache *refs,
1042                                         const char *refname, unsigned char *sha1,
1043                                         int recursion)
1044{
1045        int fd, len;
1046        char buffer[128], *p;
1047        char *path;
1048
1049        if (recursion > MAXDEPTH || strlen(refname) > MAXREFLEN)
1050                return -1;
1051        path = *refs->name
1052                ? git_path_submodule(refs->name, "%s", refname)
1053                : git_path("%s", refname);
1054        fd = open(path, O_RDONLY);
1055        if (fd < 0)
1056                return resolve_gitlink_packed_ref(refs, refname, sha1);
1057
1058        len = read(fd, buffer, sizeof(buffer)-1);
1059        close(fd);
1060        if (len < 0)
1061                return -1;
1062        while (len && isspace(buffer[len-1]))
1063                len--;
1064        buffer[len] = 0;
1065
1066        /* Was it a detached head or an old-fashioned symlink? */
1067        if (!get_sha1_hex(buffer, sha1))
1068                return 0;
1069
1070        /* Symref? */
1071        if (strncmp(buffer, "ref:", 4))
1072                return -1;
1073        p = buffer + 4;
1074        while (isspace(*p))
1075                p++;
1076
1077        return resolve_gitlink_ref_recursive(refs, p, sha1, recursion+1);
1078}
1079
1080int resolve_gitlink_ref(const char *path, const char *refname, unsigned char *sha1)
1081{
1082        int len = strlen(path), retval;
1083        char *submodule;
1084        struct ref_cache *refs;
1085
1086        while (len && path[len-1] == '/')
1087                len--;
1088        if (!len)
1089                return -1;
1090        submodule = xstrndup(path, len);
1091        refs = get_ref_cache(submodule);
1092        free(submodule);
1093
1094        retval = resolve_gitlink_ref_recursive(refs, refname, sha1, 0);
1095        return retval;
1096}
1097
1098/*
1099 * Try to read ref from the packed references.  On success, set sha1
1100 * and return 0; otherwise, return -1.
1101 */
1102static int get_packed_ref(const char *refname, unsigned char *sha1)
1103{
1104        struct ref_dir *packed = get_packed_refs(get_ref_cache(NULL));
1105        struct ref_entry *entry = find_ref(packed, refname);
1106        if (entry) {
1107                hashcpy(sha1, entry->u.value.sha1);
1108                return 0;
1109        }
1110        return -1;
1111}
1112
1113const char *resolve_ref_unsafe(const char *refname, unsigned char *sha1, int reading, int *flag)
1114{
1115        int depth = MAXDEPTH;
1116        ssize_t len;
1117        char buffer[256];
1118        static char refname_buffer[256];
1119
1120        if (flag)
1121                *flag = 0;
1122
1123        if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL))
1124                return NULL;
1125
1126        for (;;) {
1127                char path[PATH_MAX];
1128                struct stat st;
1129                char *buf;
1130                int fd;
1131
1132                if (--depth < 0)
1133                        return NULL;
1134
1135                git_snpath(path, sizeof(path), "%s", refname);
1136
1137                if (lstat(path, &st) < 0) {
1138                        if (errno != ENOENT)
1139                                return NULL;
1140                        /*
1141                         * The loose reference file does not exist;
1142                         * check for a packed reference.
1143                         */
1144                        if (!get_packed_ref(refname, sha1)) {
1145                                if (flag)
1146                                        *flag |= REF_ISPACKED;
1147                                return refname;
1148                        }
1149                        /* The reference is not a packed reference, either. */
1150                        if (reading) {
1151                                return NULL;
1152                        } else {
1153                                hashclr(sha1);
1154                                return refname;
1155                        }
1156                }
1157
1158                /* Follow "normalized" - ie "refs/.." symlinks by hand */
1159                if (S_ISLNK(st.st_mode)) {
1160                        len = readlink(path, buffer, sizeof(buffer)-1);
1161                        if (len < 0)
1162                                return NULL;
1163                        buffer[len] = 0;
1164                        if (!prefixcmp(buffer, "refs/") &&
1165                                        !check_refname_format(buffer, 0)) {
1166                                strcpy(refname_buffer, buffer);
1167                                refname = refname_buffer;
1168                                if (flag)
1169                                        *flag |= REF_ISSYMREF;
1170                                continue;
1171                        }
1172                }
1173
1174                /* Is it a directory? */
1175                if (S_ISDIR(st.st_mode)) {
1176                        errno = EISDIR;
1177                        return NULL;
1178                }
1179
1180                /*
1181                 * Anything else, just open it and try to use it as
1182                 * a ref
1183                 */
1184                fd = open(path, O_RDONLY);
1185                if (fd < 0)
1186                        return NULL;
1187                len = read_in_full(fd, buffer, sizeof(buffer)-1);
1188                close(fd);
1189                if (len < 0)
1190                        return NULL;
1191                while (len && isspace(buffer[len-1]))
1192                        len--;
1193                buffer[len] = '\0';
1194
1195                /*
1196                 * Is it a symbolic ref?
1197                 */
1198                if (prefixcmp(buffer, "ref:"))
1199                        break;
1200                if (flag)
1201                        *flag |= REF_ISSYMREF;
1202                buf = buffer + 4;
1203                while (isspace(*buf))
1204                        buf++;
1205                if (check_refname_format(buf, REFNAME_ALLOW_ONELEVEL)) {
1206                        if (flag)
1207                                *flag |= REF_ISBROKEN;
1208                        return NULL;
1209                }
1210                refname = strcpy(refname_buffer, buf);
1211        }
1212        /* Please note that FETCH_HEAD has a second line containing other data. */
1213        if (get_sha1_hex(buffer, sha1) || (buffer[40] != '\0' && !isspace(buffer[40]))) {
1214                if (flag)
1215                        *flag |= REF_ISBROKEN;
1216                return NULL;
1217        }
1218        return refname;
1219}
1220
1221char *resolve_refdup(const char *ref, unsigned char *sha1, int reading, int *flag)
1222{
1223        const char *ret = resolve_ref_unsafe(ref, sha1, reading, flag);
1224        return ret ? xstrdup(ret) : NULL;
1225}
1226
1227/* The argument to filter_refs */
1228struct ref_filter {
1229        const char *pattern;
1230        each_ref_fn *fn;
1231        void *cb_data;
1232};
1233
1234int read_ref_full(const char *refname, unsigned char *sha1, int reading, int *flags)
1235{
1236        if (resolve_ref_unsafe(refname, sha1, reading, flags))
1237                return 0;
1238        return -1;
1239}
1240
1241int read_ref(const char *refname, unsigned char *sha1)
1242{
1243        return read_ref_full(refname, sha1, 1, NULL);
1244}
1245
1246int ref_exists(const char *refname)
1247{
1248        unsigned char sha1[20];
1249        return !!resolve_ref_unsafe(refname, sha1, 1, NULL);
1250}
1251
1252static int filter_refs(const char *refname, const unsigned char *sha1, int flags,
1253                       void *data)
1254{
1255        struct ref_filter *filter = (struct ref_filter *)data;
1256        if (fnmatch(filter->pattern, refname, 0))
1257                return 0;
1258        return filter->fn(refname, sha1, flags, filter->cb_data);
1259}
1260
1261int peel_ref(const char *refname, unsigned char *sha1)
1262{
1263        int flag;
1264        unsigned char base[20];
1265        struct object *o;
1266
1267        if (current_ref && (current_ref->name == refname
1268                || !strcmp(current_ref->name, refname))) {
1269                if (current_ref->flag & REF_KNOWS_PEELED) {
1270                        if (is_null_sha1(current_ref->u.value.peeled))
1271                            return -1;
1272                        hashcpy(sha1, current_ref->u.value.peeled);
1273                        return 0;
1274                }
1275                hashcpy(base, current_ref->u.value.sha1);
1276                goto fallback;
1277        }
1278
1279        if (read_ref_full(refname, base, 1, &flag))
1280                return -1;
1281
1282        if ((flag & REF_ISPACKED)) {
1283                struct ref_dir *dir = get_packed_refs(get_ref_cache(NULL));
1284                struct ref_entry *r = find_ref(dir, refname);
1285
1286                if (r != NULL && r->flag & REF_KNOWS_PEELED) {
1287                        hashcpy(sha1, r->u.value.peeled);
1288                        return 0;
1289                }
1290        }
1291
1292fallback:
1293        o = lookup_unknown_object(base);
1294        if (o->type == OBJ_NONE) {
1295                int type = sha1_object_info(base, NULL);
1296                if (type < 0)
1297                        return -1;
1298                o->type = type;
1299        }
1300
1301        if (o->type == OBJ_TAG) {
1302                o = deref_tag_noverify(o);
1303                if (o) {
1304                        hashcpy(sha1, o->sha1);
1305                        return 0;
1306                }
1307        }
1308        return -1;
1309}
1310
1311struct warn_if_dangling_data {
1312        FILE *fp;
1313        const char *refname;
1314        const char *msg_fmt;
1315};
1316
1317static int warn_if_dangling_symref(const char *refname, const unsigned char *sha1,
1318                                   int flags, void *cb_data)
1319{
1320        struct warn_if_dangling_data *d = cb_data;
1321        const char *resolves_to;
1322        unsigned char junk[20];
1323
1324        if (!(flags & REF_ISSYMREF))
1325                return 0;
1326
1327        resolves_to = resolve_ref_unsafe(refname, junk, 0, NULL);
1328        if (!resolves_to || strcmp(resolves_to, d->refname))
1329                return 0;
1330
1331        fprintf(d->fp, d->msg_fmt, refname);
1332        fputc('\n', d->fp);
1333        return 0;
1334}
1335
1336void warn_dangling_symref(FILE *fp, const char *msg_fmt, const char *refname)
1337{
1338        struct warn_if_dangling_data data;
1339
1340        data.fp = fp;
1341        data.refname = refname;
1342        data.msg_fmt = msg_fmt;
1343        for_each_rawref(warn_if_dangling_symref, &data);
1344}
1345
1346/*
1347 * Call fn for each reference in the specified submodule for which the
1348 * refname begins with base.  If trim is non-zero, then trim that many
1349 * characters off the beginning of each refname before passing the
1350 * refname to fn.  flags can be DO_FOR_EACH_INCLUDE_BROKEN to include
1351 * broken references in the iteration.  If fn ever returns a non-zero
1352 * value, stop the iteration and return that value; otherwise, return
1353 * 0.
1354 */
1355static int do_for_each_ref(const char *submodule, const char *base, each_ref_fn fn,
1356                           int trim, int flags, void *cb_data)
1357{
1358        struct ref_cache *refs = get_ref_cache(submodule);
1359        struct ref_dir *packed_dir = get_packed_refs(refs);
1360        struct ref_dir *loose_dir = get_loose_refs(refs);
1361        int retval = 0;
1362
1363        if (base && *base) {
1364                packed_dir = find_containing_dir(packed_dir, base, 0);
1365                loose_dir = find_containing_dir(loose_dir, base, 0);
1366        }
1367
1368        if (packed_dir && loose_dir) {
1369                sort_ref_dir(packed_dir);
1370                sort_ref_dir(loose_dir);
1371                retval = do_for_each_ref_in_dirs(
1372                                packed_dir, loose_dir,
1373                                base, fn, trim, flags, cb_data);
1374        } else if (packed_dir) {
1375                sort_ref_dir(packed_dir);
1376                retval = do_for_each_ref_in_dir(
1377                                packed_dir, 0,
1378                                base, fn, trim, flags, cb_data);
1379        } else if (loose_dir) {
1380                sort_ref_dir(loose_dir);
1381                retval = do_for_each_ref_in_dir(
1382                                loose_dir, 0,
1383                                base, fn, trim, flags, cb_data);
1384        }
1385
1386        return retval;
1387}
1388
1389static int do_head_ref(const char *submodule, each_ref_fn fn, void *cb_data)
1390{
1391        unsigned char sha1[20];
1392        int flag;
1393
1394        if (submodule) {
1395                if (resolve_gitlink_ref(submodule, "HEAD", sha1) == 0)
1396                        return fn("HEAD", sha1, 0, cb_data);
1397
1398                return 0;
1399        }
1400
1401        if (!read_ref_full("HEAD", sha1, 1, &flag))
1402                return fn("HEAD", sha1, flag, cb_data);
1403
1404        return 0;
1405}
1406
1407int head_ref(each_ref_fn fn, void *cb_data)
1408{
1409        return do_head_ref(NULL, fn, cb_data);
1410}
1411
1412int head_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
1413{
1414        return do_head_ref(submodule, fn, cb_data);
1415}
1416
1417int for_each_ref(each_ref_fn fn, void *cb_data)
1418{
1419        return do_for_each_ref(NULL, "", fn, 0, 0, cb_data);
1420}
1421
1422int for_each_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
1423{
1424        return do_for_each_ref(submodule, "", fn, 0, 0, cb_data);
1425}
1426
1427int for_each_ref_in(const char *prefix, each_ref_fn fn, void *cb_data)
1428{
1429        return do_for_each_ref(NULL, prefix, fn, strlen(prefix), 0, cb_data);
1430}
1431
1432int for_each_ref_in_submodule(const char *submodule, const char *prefix,
1433                each_ref_fn fn, void *cb_data)
1434{
1435        return do_for_each_ref(submodule, prefix, fn, strlen(prefix), 0, cb_data);
1436}
1437
1438int for_each_tag_ref(each_ref_fn fn, void *cb_data)
1439{
1440        return for_each_ref_in("refs/tags/", fn, cb_data);
1441}
1442
1443int for_each_tag_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
1444{
1445        return for_each_ref_in_submodule(submodule, "refs/tags/", fn, cb_data);
1446}
1447
1448int for_each_branch_ref(each_ref_fn fn, void *cb_data)
1449{
1450        return for_each_ref_in("refs/heads/", fn, cb_data);
1451}
1452
1453int for_each_branch_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
1454{
1455        return for_each_ref_in_submodule(submodule, "refs/heads/", fn, cb_data);
1456}
1457
1458int for_each_remote_ref(each_ref_fn fn, void *cb_data)
1459{
1460        return for_each_ref_in("refs/remotes/", fn, cb_data);
1461}
1462
1463int for_each_remote_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
1464{
1465        return for_each_ref_in_submodule(submodule, "refs/remotes/", fn, cb_data);
1466}
1467
1468int for_each_replace_ref(each_ref_fn fn, void *cb_data)
1469{
1470        return do_for_each_ref(NULL, "refs/replace/", fn, 13, 0, cb_data);
1471}
1472
1473int head_ref_namespaced(each_ref_fn fn, void *cb_data)
1474{
1475        struct strbuf buf = STRBUF_INIT;
1476        int ret = 0;
1477        unsigned char sha1[20];
1478        int flag;
1479
1480        strbuf_addf(&buf, "%sHEAD", get_git_namespace());
1481        if (!read_ref_full(buf.buf, sha1, 1, &flag))
1482                ret = fn(buf.buf, sha1, flag, cb_data);
1483        strbuf_release(&buf);
1484
1485        return ret;
1486}
1487
1488int for_each_namespaced_ref(each_ref_fn fn, void *cb_data)
1489{
1490        struct strbuf buf = STRBUF_INIT;
1491        int ret;
1492        strbuf_addf(&buf, "%srefs/", get_git_namespace());
1493        ret = do_for_each_ref(NULL, buf.buf, fn, 0, 0, cb_data);
1494        strbuf_release(&buf);
1495        return ret;
1496}
1497
1498int for_each_glob_ref_in(each_ref_fn fn, const char *pattern,
1499        const char *prefix, void *cb_data)
1500{
1501        struct strbuf real_pattern = STRBUF_INIT;
1502        struct ref_filter filter;
1503        int ret;
1504
1505        if (!prefix && prefixcmp(pattern, "refs/"))
1506                strbuf_addstr(&real_pattern, "refs/");
1507        else if (prefix)
1508                strbuf_addstr(&real_pattern, prefix);
1509        strbuf_addstr(&real_pattern, pattern);
1510
1511        if (!has_glob_specials(pattern)) {
1512                /* Append implied '/' '*' if not present. */
1513                if (real_pattern.buf[real_pattern.len - 1] != '/')
1514                        strbuf_addch(&real_pattern, '/');
1515                /* No need to check for '*', there is none. */
1516                strbuf_addch(&real_pattern, '*');
1517        }
1518
1519        filter.pattern = real_pattern.buf;
1520        filter.fn = fn;
1521        filter.cb_data = cb_data;
1522        ret = for_each_ref(filter_refs, &filter);
1523
1524        strbuf_release(&real_pattern);
1525        return ret;
1526}
1527
1528int for_each_glob_ref(each_ref_fn fn, const char *pattern, void *cb_data)
1529{
1530        return for_each_glob_ref_in(fn, pattern, NULL, cb_data);
1531}
1532
1533int for_each_rawref(each_ref_fn fn, void *cb_data)
1534{
1535        return do_for_each_ref(NULL, "", fn, 0,
1536                               DO_FOR_EACH_INCLUDE_BROKEN, cb_data);
1537}
1538
1539const char *prettify_refname(const char *name)
1540{
1541        return name + (
1542                !prefixcmp(name, "refs/heads/") ? 11 :
1543                !prefixcmp(name, "refs/tags/") ? 10 :
1544                !prefixcmp(name, "refs/remotes/") ? 13 :
1545                0);
1546}
1547
1548const char *ref_rev_parse_rules[] = {
1549        "%.*s",
1550        "refs/%.*s",
1551        "refs/tags/%.*s",
1552        "refs/heads/%.*s",
1553        "refs/remotes/%.*s",
1554        "refs/remotes/%.*s/HEAD",
1555        NULL
1556};
1557
1558int refname_match(const char *abbrev_name, const char *full_name, const char **rules)
1559{
1560        const char **p;
1561        const int abbrev_name_len = strlen(abbrev_name);
1562
1563        for (p = rules; *p; p++) {
1564                if (!strcmp(full_name, mkpath(*p, abbrev_name_len, abbrev_name))) {
1565                        return 1;
1566                }
1567        }
1568
1569        return 0;
1570}
1571
1572static struct ref_lock *verify_lock(struct ref_lock *lock,
1573        const unsigned char *old_sha1, int mustexist)
1574{
1575        if (read_ref_full(lock->ref_name, lock->old_sha1, mustexist, NULL)) {
1576                error("Can't verify ref %s", lock->ref_name);
1577                unlock_ref(lock);
1578                return NULL;
1579        }
1580        if (hashcmp(lock->old_sha1, old_sha1)) {
1581                error("Ref %s is at %s but expected %s", lock->ref_name,
1582                        sha1_to_hex(lock->old_sha1), sha1_to_hex(old_sha1));
1583                unlock_ref(lock);
1584                return NULL;
1585        }
1586        return lock;
1587}
1588
1589static int remove_empty_directories(const char *file)
1590{
1591        /* we want to create a file but there is a directory there;
1592         * if that is an empty directory (or a directory that contains
1593         * only empty directories), remove them.
1594         */
1595        struct strbuf path;
1596        int result;
1597
1598        strbuf_init(&path, 20);
1599        strbuf_addstr(&path, file);
1600
1601        result = remove_dir_recursively(&path, REMOVE_DIR_EMPTY_ONLY);
1602
1603        strbuf_release(&path);
1604
1605        return result;
1606}
1607
1608/*
1609 * *string and *len will only be substituted, and *string returned (for
1610 * later free()ing) if the string passed in is a magic short-hand form
1611 * to name a branch.
1612 */
1613static char *substitute_branch_name(const char **string, int *len)
1614{
1615        struct strbuf buf = STRBUF_INIT;
1616        int ret = interpret_branch_name(*string, &buf);
1617
1618        if (ret == *len) {
1619                size_t size;
1620                *string = strbuf_detach(&buf, &size);
1621                *len = size;
1622                return (char *)*string;
1623        }
1624
1625        return NULL;
1626}
1627
1628int dwim_ref(const char *str, int len, unsigned char *sha1, char **ref)
1629{
1630        char *last_branch = substitute_branch_name(&str, &len);
1631        const char **p, *r;
1632        int refs_found = 0;
1633
1634        *ref = NULL;
1635        for (p = ref_rev_parse_rules; *p; p++) {
1636                char fullref[PATH_MAX];
1637                unsigned char sha1_from_ref[20];
1638                unsigned char *this_result;
1639                int flag;
1640
1641                this_result = refs_found ? sha1_from_ref : sha1;
1642                mksnpath(fullref, sizeof(fullref), *p, len, str);
1643                r = resolve_ref_unsafe(fullref, this_result, 1, &flag);
1644                if (r) {
1645                        if (!refs_found++)
1646                                *ref = xstrdup(r);
1647                        if (!warn_ambiguous_refs)
1648                                break;
1649                } else if ((flag & REF_ISSYMREF) && strcmp(fullref, "HEAD")) {
1650                        warning("ignoring dangling symref %s.", fullref);
1651                } else if ((flag & REF_ISBROKEN) && strchr(fullref, '/')) {
1652                        warning("ignoring broken ref %s.", fullref);
1653                }
1654        }
1655        free(last_branch);
1656        return refs_found;
1657}
1658
1659int dwim_log(const char *str, int len, unsigned char *sha1, char **log)
1660{
1661        char *last_branch = substitute_branch_name(&str, &len);
1662        const char **p;
1663        int logs_found = 0;
1664
1665        *log = NULL;
1666        for (p = ref_rev_parse_rules; *p; p++) {
1667                struct stat st;
1668                unsigned char hash[20];
1669                char path[PATH_MAX];
1670                const char *ref, *it;
1671
1672                mksnpath(path, sizeof(path), *p, len, str);
1673                ref = resolve_ref_unsafe(path, hash, 1, NULL);
1674                if (!ref)
1675                        continue;
1676                if (!stat(git_path("logs/%s", path), &st) &&
1677                    S_ISREG(st.st_mode))
1678                        it = path;
1679                else if (strcmp(ref, path) &&
1680                         !stat(git_path("logs/%s", ref), &st) &&
1681                         S_ISREG(st.st_mode))
1682                        it = ref;
1683                else
1684                        continue;
1685                if (!logs_found++) {
1686                        *log = xstrdup(it);
1687                        hashcpy(sha1, hash);
1688                }
1689                if (!warn_ambiguous_refs)
1690                        break;
1691        }
1692        free(last_branch);
1693        return logs_found;
1694}
1695
1696static struct ref_lock *lock_ref_sha1_basic(const char *refname,
1697                                            const unsigned char *old_sha1,
1698                                            int flags, int *type_p)
1699{
1700        char *ref_file;
1701        const char *orig_refname = refname;
1702        struct ref_lock *lock;
1703        int last_errno = 0;
1704        int type, lflags;
1705        int mustexist = (old_sha1 && !is_null_sha1(old_sha1));
1706        int missing = 0;
1707
1708        lock = xcalloc(1, sizeof(struct ref_lock));
1709        lock->lock_fd = -1;
1710
1711        refname = resolve_ref_unsafe(refname, lock->old_sha1, mustexist, &type);
1712        if (!refname && errno == EISDIR) {
1713                /* we are trying to lock foo but we used to
1714                 * have foo/bar which now does not exist;
1715                 * it is normal for the empty directory 'foo'
1716                 * to remain.
1717                 */
1718                ref_file = git_path("%s", orig_refname);
1719                if (remove_empty_directories(ref_file)) {
1720                        last_errno = errno;
1721                        error("there are still refs under '%s'", orig_refname);
1722                        goto error_return;
1723                }
1724                refname = resolve_ref_unsafe(orig_refname, lock->old_sha1, mustexist, &type);
1725        }
1726        if (type_p)
1727            *type_p = type;
1728        if (!refname) {
1729                last_errno = errno;
1730                error("unable to resolve reference %s: %s",
1731                        orig_refname, strerror(errno));
1732                goto error_return;
1733        }
1734        missing = is_null_sha1(lock->old_sha1);
1735        /* When the ref did not exist and we are creating it,
1736         * make sure there is no existing ref that is packed
1737         * whose name begins with our refname, nor a ref whose
1738         * name is a proper prefix of our refname.
1739         */
1740        if (missing &&
1741             !is_refname_available(refname, NULL, get_packed_refs(get_ref_cache(NULL)))) {
1742                last_errno = ENOTDIR;
1743                goto error_return;
1744        }
1745
1746        lock->lk = xcalloc(1, sizeof(struct lock_file));
1747
1748        lflags = LOCK_DIE_ON_ERROR;
1749        if (flags & REF_NODEREF) {
1750                refname = orig_refname;
1751                lflags |= LOCK_NODEREF;
1752        }
1753        lock->ref_name = xstrdup(refname);
1754        lock->orig_ref_name = xstrdup(orig_refname);
1755        ref_file = git_path("%s", refname);
1756        if (missing)
1757                lock->force_write = 1;
1758        if ((flags & REF_NODEREF) && (type & REF_ISSYMREF))
1759                lock->force_write = 1;
1760
1761        if (safe_create_leading_directories(ref_file)) {
1762                last_errno = errno;
1763                error("unable to create directory for %s", ref_file);
1764                goto error_return;
1765        }
1766
1767        lock->lock_fd = hold_lock_file_for_update(lock->lk, ref_file, lflags);
1768        return old_sha1 ? verify_lock(lock, old_sha1, mustexist) : lock;
1769
1770 error_return:
1771        unlock_ref(lock);
1772        errno = last_errno;
1773        return NULL;
1774}
1775
1776struct ref_lock *lock_ref_sha1(const char *refname, const unsigned char *old_sha1)
1777{
1778        char refpath[PATH_MAX];
1779        if (check_refname_format(refname, 0))
1780                return NULL;
1781        strcpy(refpath, mkpath("refs/%s", refname));
1782        return lock_ref_sha1_basic(refpath, old_sha1, 0, NULL);
1783}
1784
1785struct ref_lock *lock_any_ref_for_update(const char *refname,
1786                                         const unsigned char *old_sha1, int flags)
1787{
1788        if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL))
1789                return NULL;
1790        return lock_ref_sha1_basic(refname, old_sha1, flags, NULL);
1791}
1792
1793struct repack_without_ref_sb {
1794        const char *refname;
1795        int fd;
1796};
1797
1798static int repack_without_ref_fn(const char *refname, const unsigned char *sha1,
1799                                 int flags, void *cb_data)
1800{
1801        struct repack_without_ref_sb *data = cb_data;
1802        char line[PATH_MAX + 100];
1803        int len;
1804
1805        if (!strcmp(data->refname, refname))
1806                return 0;
1807        len = snprintf(line, sizeof(line), "%s %s\n",
1808                       sha1_to_hex(sha1), refname);
1809        /* this should not happen but just being defensive */
1810        if (len > sizeof(line))
1811                die("too long a refname '%s'", refname);
1812        write_or_die(data->fd, line, len);
1813        return 0;
1814}
1815
1816static struct lock_file packlock;
1817
1818static int repack_without_ref(const char *refname)
1819{
1820        struct repack_without_ref_sb data;
1821        struct ref_cache *refs = get_ref_cache(NULL);
1822        struct ref_dir *packed = get_packed_refs(refs);
1823        if (find_ref(packed, refname) == NULL)
1824                return 0;
1825        data.refname = refname;
1826        data.fd = hold_lock_file_for_update(&packlock, git_path("packed-refs"), 0);
1827        if (data.fd < 0) {
1828                unable_to_lock_error(git_path("packed-refs"), errno);
1829                return error("cannot delete '%s' from packed refs", refname);
1830        }
1831        clear_packed_ref_cache(refs);
1832        packed = get_packed_refs(refs);
1833        do_for_each_ref_in_dir(packed, 0, "", repack_without_ref_fn, 0, 0, &data);
1834        return commit_lock_file(&packlock);
1835}
1836
1837int delete_ref(const char *refname, const unsigned char *sha1, int delopt)
1838{
1839        struct ref_lock *lock;
1840        int err, i = 0, ret = 0, flag = 0;
1841
1842        lock = lock_ref_sha1_basic(refname, sha1, delopt, &flag);
1843        if (!lock)
1844                return 1;
1845        if (!(flag & REF_ISPACKED) || flag & REF_ISSYMREF) {
1846                /* loose */
1847                i = strlen(lock->lk->filename) - 5; /* .lock */
1848                lock->lk->filename[i] = 0;
1849                err = unlink_or_warn(lock->lk->filename);
1850                if (err && errno != ENOENT)
1851                        ret = 1;
1852
1853                lock->lk->filename[i] = '.';
1854        }
1855        /* removing the loose one could have resurrected an earlier
1856         * packed one.  Also, if it was not loose we need to repack
1857         * without it.
1858         */
1859        ret |= repack_without_ref(lock->ref_name);
1860
1861        unlink_or_warn(git_path("logs/%s", lock->ref_name));
1862        invalidate_ref_cache(NULL);
1863        unlock_ref(lock);
1864        return ret;
1865}
1866
1867/*
1868 * People using contrib's git-new-workdir have .git/logs/refs ->
1869 * /some/other/path/.git/logs/refs, and that may live on another device.
1870 *
1871 * IOW, to avoid cross device rename errors, the temporary renamed log must
1872 * live into logs/refs.
1873 */
1874#define TMP_RENAMED_LOG  "logs/refs/.tmp-renamed-log"
1875
1876int rename_ref(const char *oldrefname, const char *newrefname, const char *logmsg)
1877{
1878        unsigned char sha1[20], orig_sha1[20];
1879        int flag = 0, logmoved = 0;
1880        struct ref_lock *lock;
1881        struct stat loginfo;
1882        int log = !lstat(git_path("logs/%s", oldrefname), &loginfo);
1883        const char *symref = NULL;
1884        struct ref_cache *refs = get_ref_cache(NULL);
1885
1886        if (log && S_ISLNK(loginfo.st_mode))
1887                return error("reflog for %s is a symlink", oldrefname);
1888
1889        symref = resolve_ref_unsafe(oldrefname, orig_sha1, 1, &flag);
1890        if (flag & REF_ISSYMREF)
1891                return error("refname %s is a symbolic ref, renaming it is not supported",
1892                        oldrefname);
1893        if (!symref)
1894                return error("refname %s not found", oldrefname);
1895
1896        if (!is_refname_available(newrefname, oldrefname, get_packed_refs(refs)))
1897                return 1;
1898
1899        if (!is_refname_available(newrefname, oldrefname, get_loose_refs(refs)))
1900                return 1;
1901
1902        if (log && rename(git_path("logs/%s", oldrefname), git_path(TMP_RENAMED_LOG)))
1903                return error("unable to move logfile logs/%s to "TMP_RENAMED_LOG": %s",
1904                        oldrefname, strerror(errno));
1905
1906        if (delete_ref(oldrefname, orig_sha1, REF_NODEREF)) {
1907                error("unable to delete old %s", oldrefname);
1908                goto rollback;
1909        }
1910
1911        if (!read_ref_full(newrefname, sha1, 1, &flag) &&
1912            delete_ref(newrefname, sha1, REF_NODEREF)) {
1913                if (errno==EISDIR) {
1914                        if (remove_empty_directories(git_path("%s", newrefname))) {
1915                                error("Directory not empty: %s", newrefname);
1916                                goto rollback;
1917                        }
1918                } else {
1919                        error("unable to delete existing %s", newrefname);
1920                        goto rollback;
1921                }
1922        }
1923
1924        if (log && safe_create_leading_directories(git_path("logs/%s", newrefname))) {
1925                error("unable to create directory for %s", newrefname);
1926                goto rollback;
1927        }
1928
1929 retry:
1930        if (log && rename(git_path(TMP_RENAMED_LOG), git_path("logs/%s", newrefname))) {
1931                if (errno==EISDIR || errno==ENOTDIR) {
1932                        /*
1933                         * rename(a, b) when b is an existing
1934                         * directory ought to result in ISDIR, but
1935                         * Solaris 5.8 gives ENOTDIR.  Sheesh.
1936                         */
1937                        if (remove_empty_directories(git_path("logs/%s", newrefname))) {
1938                                error("Directory not empty: logs/%s", newrefname);
1939                                goto rollback;
1940                        }
1941                        goto retry;
1942                } else {
1943                        error("unable to move logfile "TMP_RENAMED_LOG" to logs/%s: %s",
1944                                newrefname, strerror(errno));
1945                        goto rollback;
1946                }
1947        }
1948        logmoved = log;
1949
1950        lock = lock_ref_sha1_basic(newrefname, NULL, 0, NULL);
1951        if (!lock) {
1952                error("unable to lock %s for update", newrefname);
1953                goto rollback;
1954        }
1955        lock->force_write = 1;
1956        hashcpy(lock->old_sha1, orig_sha1);
1957        if (write_ref_sha1(lock, orig_sha1, logmsg)) {
1958                error("unable to write current sha1 into %s", newrefname);
1959                goto rollback;
1960        }
1961
1962        return 0;
1963
1964 rollback:
1965        lock = lock_ref_sha1_basic(oldrefname, NULL, 0, NULL);
1966        if (!lock) {
1967                error("unable to lock %s for rollback", oldrefname);
1968                goto rollbacklog;
1969        }
1970
1971        lock->force_write = 1;
1972        flag = log_all_ref_updates;
1973        log_all_ref_updates = 0;
1974        if (write_ref_sha1(lock, orig_sha1, NULL))
1975                error("unable to write current sha1 into %s", oldrefname);
1976        log_all_ref_updates = flag;
1977
1978 rollbacklog:
1979        if (logmoved && rename(git_path("logs/%s", newrefname), git_path("logs/%s", oldrefname)))
1980                error("unable to restore logfile %s from %s: %s",
1981                        oldrefname, newrefname, strerror(errno));
1982        if (!logmoved && log &&
1983            rename(git_path(TMP_RENAMED_LOG), git_path("logs/%s", oldrefname)))
1984                error("unable to restore logfile %s from "TMP_RENAMED_LOG": %s",
1985                        oldrefname, strerror(errno));
1986
1987        return 1;
1988}
1989
1990int close_ref(struct ref_lock *lock)
1991{
1992        if (close_lock_file(lock->lk))
1993                return -1;
1994        lock->lock_fd = -1;
1995        return 0;
1996}
1997
1998int commit_ref(struct ref_lock *lock)
1999{
2000        if (commit_lock_file(lock->lk))
2001                return -1;
2002        lock->lock_fd = -1;
2003        return 0;
2004}
2005
2006void unlock_ref(struct ref_lock *lock)
2007{
2008        /* Do not free lock->lk -- atexit() still looks at them */
2009        if (lock->lk)
2010                rollback_lock_file(lock->lk);
2011        free(lock->ref_name);
2012        free(lock->orig_ref_name);
2013        free(lock);
2014}
2015
2016/*
2017 * copy the reflog message msg to buf, which has been allocated sufficiently
2018 * large, while cleaning up the whitespaces.  Especially, convert LF to space,
2019 * because reflog file is one line per entry.
2020 */
2021static int copy_msg(char *buf, const char *msg)
2022{
2023        char *cp = buf;
2024        char c;
2025        int wasspace = 1;
2026
2027        *cp++ = '\t';
2028        while ((c = *msg++)) {
2029                if (wasspace && isspace(c))
2030                        continue;
2031                wasspace = isspace(c);
2032                if (wasspace)
2033                        c = ' ';
2034                *cp++ = c;
2035        }
2036        while (buf < cp && isspace(cp[-1]))
2037                cp--;
2038        *cp++ = '\n';
2039        return cp - buf;
2040}
2041
2042int log_ref_setup(const char *refname, char *logfile, int bufsize)
2043{
2044        int logfd, oflags = O_APPEND | O_WRONLY;
2045
2046        git_snpath(logfile, bufsize, "logs/%s", refname);
2047        if (log_all_ref_updates &&
2048            (!prefixcmp(refname, "refs/heads/") ||
2049             !prefixcmp(refname, "refs/remotes/") ||
2050             !prefixcmp(refname, "refs/notes/") ||
2051             !strcmp(refname, "HEAD"))) {
2052                if (safe_create_leading_directories(logfile) < 0)
2053                        return error("unable to create directory for %s",
2054                                     logfile);
2055                oflags |= O_CREAT;
2056        }
2057
2058        logfd = open(logfile, oflags, 0666);
2059        if (logfd < 0) {
2060                if (!(oflags & O_CREAT) && errno == ENOENT)
2061                        return 0;
2062
2063                if ((oflags & O_CREAT) && errno == EISDIR) {
2064                        if (remove_empty_directories(logfile)) {
2065                                return error("There are still logs under '%s'",
2066                                             logfile);
2067                        }
2068                        logfd = open(logfile, oflags, 0666);
2069                }
2070
2071                if (logfd < 0)
2072                        return error("Unable to append to %s: %s",
2073                                     logfile, strerror(errno));
2074        }
2075
2076        adjust_shared_perm(logfile);
2077        close(logfd);
2078        return 0;
2079}
2080
2081static int log_ref_write(const char *refname, const unsigned char *old_sha1,
2082                         const unsigned char *new_sha1, const char *msg)
2083{
2084        int logfd, result, written, oflags = O_APPEND | O_WRONLY;
2085        unsigned maxlen, len;
2086        int msglen;
2087        char log_file[PATH_MAX];
2088        char *logrec;
2089        const char *committer;
2090
2091        if (log_all_ref_updates < 0)
2092                log_all_ref_updates = !is_bare_repository();
2093
2094        result = log_ref_setup(refname, log_file, sizeof(log_file));
2095        if (result)
2096                return result;
2097
2098        logfd = open(log_file, oflags);
2099        if (logfd < 0)
2100                return 0;
2101        msglen = msg ? strlen(msg) : 0;
2102        committer = git_committer_info(0);
2103        maxlen = strlen(committer) + msglen + 100;
2104        logrec = xmalloc(maxlen);
2105        len = sprintf(logrec, "%s %s %s\n",
2106                      sha1_to_hex(old_sha1),
2107                      sha1_to_hex(new_sha1),
2108                      committer);
2109        if (msglen)
2110                len += copy_msg(logrec + len - 1, msg) - 1;
2111        written = len <= maxlen ? write_in_full(logfd, logrec, len) : -1;
2112        free(logrec);
2113        if (close(logfd) != 0 || written != len)
2114                return error("Unable to append to %s", log_file);
2115        return 0;
2116}
2117
2118static int is_branch(const char *refname)
2119{
2120        return !strcmp(refname, "HEAD") || !prefixcmp(refname, "refs/heads/");
2121}
2122
2123int write_ref_sha1(struct ref_lock *lock,
2124        const unsigned char *sha1, const char *logmsg)
2125{
2126        static char term = '\n';
2127        struct object *o;
2128
2129        if (!lock)
2130                return -1;
2131        if (!lock->force_write && !hashcmp(lock->old_sha1, sha1)) {
2132                unlock_ref(lock);
2133                return 0;
2134        }
2135        o = parse_object(sha1);
2136        if (!o) {
2137                error("Trying to write ref %s with nonexistent object %s",
2138                        lock->ref_name, sha1_to_hex(sha1));
2139                unlock_ref(lock);
2140                return -1;
2141        }
2142        if (o->type != OBJ_COMMIT && is_branch(lock->ref_name)) {
2143                error("Trying to write non-commit object %s to branch %s",
2144                        sha1_to_hex(sha1), lock->ref_name);
2145                unlock_ref(lock);
2146                return -1;
2147        }
2148        if (write_in_full(lock->lock_fd, sha1_to_hex(sha1), 40) != 40 ||
2149            write_in_full(lock->lock_fd, &term, 1) != 1
2150                || close_ref(lock) < 0) {
2151                error("Couldn't write %s", lock->lk->filename);
2152                unlock_ref(lock);
2153                return -1;
2154        }
2155        clear_loose_ref_cache(get_ref_cache(NULL));
2156        if (log_ref_write(lock->ref_name, lock->old_sha1, sha1, logmsg) < 0 ||
2157            (strcmp(lock->ref_name, lock->orig_ref_name) &&
2158             log_ref_write(lock->orig_ref_name, lock->old_sha1, sha1, logmsg) < 0)) {
2159                unlock_ref(lock);
2160                return -1;
2161        }
2162        if (strcmp(lock->orig_ref_name, "HEAD") != 0) {
2163                /*
2164                 * Special hack: If a branch is updated directly and HEAD
2165                 * points to it (may happen on the remote side of a push
2166                 * for example) then logically the HEAD reflog should be
2167                 * updated too.
2168                 * A generic solution implies reverse symref information,
2169                 * but finding all symrefs pointing to the given branch
2170                 * would be rather costly for this rare event (the direct
2171                 * update of a branch) to be worth it.  So let's cheat and
2172                 * check with HEAD only which should cover 99% of all usage
2173                 * scenarios (even 100% of the default ones).
2174                 */
2175                unsigned char head_sha1[20];
2176                int head_flag;
2177                const char *head_ref;
2178                head_ref = resolve_ref_unsafe("HEAD", head_sha1, 1, &head_flag);
2179                if (head_ref && (head_flag & REF_ISSYMREF) &&
2180                    !strcmp(head_ref, lock->ref_name))
2181                        log_ref_write("HEAD", lock->old_sha1, sha1, logmsg);
2182        }
2183        if (commit_ref(lock)) {
2184                error("Couldn't set %s", lock->ref_name);
2185                unlock_ref(lock);
2186                return -1;
2187        }
2188        unlock_ref(lock);
2189        return 0;
2190}
2191
2192int create_symref(const char *ref_target, const char *refs_heads_master,
2193                  const char *logmsg)
2194{
2195        const char *lockpath;
2196        char ref[1000];
2197        int fd, len, written;
2198        char *git_HEAD = git_pathdup("%s", ref_target);
2199        unsigned char old_sha1[20], new_sha1[20];
2200
2201        if (logmsg && read_ref(ref_target, old_sha1))
2202                hashclr(old_sha1);
2203
2204        if (safe_create_leading_directories(git_HEAD) < 0)
2205                return error("unable to create directory for %s", git_HEAD);
2206
2207#ifndef NO_SYMLINK_HEAD
2208        if (prefer_symlink_refs) {
2209                unlink(git_HEAD);
2210                if (!symlink(refs_heads_master, git_HEAD))
2211                        goto done;
2212                fprintf(stderr, "no symlink - falling back to symbolic ref\n");
2213        }
2214#endif
2215
2216        len = snprintf(ref, sizeof(ref), "ref: %s\n", refs_heads_master);
2217        if (sizeof(ref) <= len) {
2218                error("refname too long: %s", refs_heads_master);
2219                goto error_free_return;
2220        }
2221        lockpath = mkpath("%s.lock", git_HEAD);
2222        fd = open(lockpath, O_CREAT | O_EXCL | O_WRONLY, 0666);
2223        if (fd < 0) {
2224                error("Unable to open %s for writing", lockpath);
2225                goto error_free_return;
2226        }
2227        written = write_in_full(fd, ref, len);
2228        if (close(fd) != 0 || written != len) {
2229                error("Unable to write to %s", lockpath);
2230                goto error_unlink_return;
2231        }
2232        if (rename(lockpath, git_HEAD) < 0) {
2233                error("Unable to create %s", git_HEAD);
2234                goto error_unlink_return;
2235        }
2236        if (adjust_shared_perm(git_HEAD)) {
2237                error("Unable to fix permissions on %s", lockpath);
2238        error_unlink_return:
2239                unlink_or_warn(lockpath);
2240        error_free_return:
2241                free(git_HEAD);
2242                return -1;
2243        }
2244
2245#ifndef NO_SYMLINK_HEAD
2246        done:
2247#endif
2248        if (logmsg && !read_ref(refs_heads_master, new_sha1))
2249                log_ref_write(ref_target, old_sha1, new_sha1, logmsg);
2250
2251        free(git_HEAD);
2252        return 0;
2253}
2254
2255static char *ref_msg(const char *line, const char *endp)
2256{
2257        const char *ep;
2258        line += 82;
2259        ep = memchr(line, '\n', endp - line);
2260        if (!ep)
2261                ep = endp;
2262        return xmemdupz(line, ep - line);
2263}
2264
2265int read_ref_at(const char *refname, unsigned long at_time, int cnt,
2266                unsigned char *sha1, char **msg,
2267                unsigned long *cutoff_time, int *cutoff_tz, int *cutoff_cnt)
2268{
2269        const char *logfile, *logdata, *logend, *rec, *lastgt, *lastrec;
2270        char *tz_c;
2271        int logfd, tz, reccnt = 0;
2272        struct stat st;
2273        unsigned long date;
2274        unsigned char logged_sha1[20];
2275        void *log_mapped;
2276        size_t mapsz;
2277
2278        logfile = git_path("logs/%s", refname);
2279        logfd = open(logfile, O_RDONLY, 0);
2280        if (logfd < 0)
2281                die_errno("Unable to read log '%s'", logfile);
2282        fstat(logfd, &st);
2283        if (!st.st_size)
2284                die("Log %s is empty.", logfile);
2285        mapsz = xsize_t(st.st_size);
2286        log_mapped = xmmap(NULL, mapsz, PROT_READ, MAP_PRIVATE, logfd, 0);
2287        logdata = log_mapped;
2288        close(logfd);
2289
2290        lastrec = NULL;
2291        rec = logend = logdata + st.st_size;
2292        while (logdata < rec) {
2293                reccnt++;
2294                if (logdata < rec && *(rec-1) == '\n')
2295                        rec--;
2296                lastgt = NULL;
2297                while (logdata < rec && *(rec-1) != '\n') {
2298                        rec--;
2299                        if (*rec == '>')
2300                                lastgt = rec;
2301                }
2302                if (!lastgt)
2303                        die("Log %s is corrupt.", logfile);
2304                date = strtoul(lastgt + 1, &tz_c, 10);
2305                if (date <= at_time || cnt == 0) {
2306                        tz = strtoul(tz_c, NULL, 10);
2307                        if (msg)
2308                                *msg = ref_msg(rec, logend);
2309                        if (cutoff_time)
2310                                *cutoff_time = date;
2311                        if (cutoff_tz)
2312                                *cutoff_tz = tz;
2313                        if (cutoff_cnt)
2314                                *cutoff_cnt = reccnt - 1;
2315                        if (lastrec) {
2316                                if (get_sha1_hex(lastrec, logged_sha1))
2317                                        die("Log %s is corrupt.", logfile);
2318                                if (get_sha1_hex(rec + 41, sha1))
2319                                        die("Log %s is corrupt.", logfile);
2320                                if (hashcmp(logged_sha1, sha1)) {
2321                                        warning("Log %s has gap after %s.",
2322                                                logfile, show_date(date, tz, DATE_RFC2822));
2323                                }
2324                        }
2325                        else if (date == at_time) {
2326                                if (get_sha1_hex(rec + 41, sha1))
2327                                        die("Log %s is corrupt.", logfile);
2328                        }
2329                        else {
2330                                if (get_sha1_hex(rec + 41, logged_sha1))
2331                                        die("Log %s is corrupt.", logfile);
2332                                if (hashcmp(logged_sha1, sha1)) {
2333                                        warning("Log %s unexpectedly ended on %s.",
2334                                                logfile, show_date(date, tz, DATE_RFC2822));
2335                                }
2336                        }
2337                        munmap(log_mapped, mapsz);
2338                        return 0;
2339                }
2340                lastrec = rec;
2341                if (cnt > 0)
2342                        cnt--;
2343        }
2344
2345        rec = logdata;
2346        while (rec < logend && *rec != '>' && *rec != '\n')
2347                rec++;
2348        if (rec == logend || *rec == '\n')
2349                die("Log %s is corrupt.", logfile);
2350        date = strtoul(rec + 1, &tz_c, 10);
2351        tz = strtoul(tz_c, NULL, 10);
2352        if (get_sha1_hex(logdata, sha1))
2353                die("Log %s is corrupt.", logfile);
2354        if (is_null_sha1(sha1)) {
2355                if (get_sha1_hex(logdata + 41, sha1))
2356                        die("Log %s is corrupt.", logfile);
2357        }
2358        if (msg)
2359                *msg = ref_msg(logdata, logend);
2360        munmap(log_mapped, mapsz);
2361
2362        if (cutoff_time)
2363                *cutoff_time = date;
2364        if (cutoff_tz)
2365                *cutoff_tz = tz;
2366        if (cutoff_cnt)
2367                *cutoff_cnt = reccnt;
2368        return 1;
2369}
2370
2371int for_each_recent_reflog_ent(const char *refname, each_reflog_ent_fn fn, long ofs, void *cb_data)
2372{
2373        const char *logfile;
2374        FILE *logfp;
2375        struct strbuf sb = STRBUF_INIT;
2376        int ret = 0;
2377
2378        logfile = git_path("logs/%s", refname);
2379        logfp = fopen(logfile, "r");
2380        if (!logfp)
2381                return -1;
2382
2383        if (ofs) {
2384                struct stat statbuf;
2385                if (fstat(fileno(logfp), &statbuf) ||
2386                    statbuf.st_size < ofs ||
2387                    fseek(logfp, -ofs, SEEK_END) ||
2388                    strbuf_getwholeline(&sb, logfp, '\n')) {
2389                        fclose(logfp);
2390                        strbuf_release(&sb);
2391                        return -1;
2392                }
2393        }
2394
2395        while (!strbuf_getwholeline(&sb, logfp, '\n')) {
2396                unsigned char osha1[20], nsha1[20];
2397                char *email_end, *message;
2398                unsigned long timestamp;
2399                int tz;
2400
2401                /* old SP new SP name <email> SP time TAB msg LF */
2402                if (sb.len < 83 || sb.buf[sb.len - 1] != '\n' ||
2403                    get_sha1_hex(sb.buf, osha1) || sb.buf[40] != ' ' ||
2404                    get_sha1_hex(sb.buf + 41, nsha1) || sb.buf[81] != ' ' ||
2405                    !(email_end = strchr(sb.buf + 82, '>')) ||
2406                    email_end[1] != ' ' ||
2407                    !(timestamp = strtoul(email_end + 2, &message, 10)) ||
2408                    !message || message[0] != ' ' ||
2409                    (message[1] != '+' && message[1] != '-') ||
2410                    !isdigit(message[2]) || !isdigit(message[3]) ||
2411                    !isdigit(message[4]) || !isdigit(message[5]))
2412                        continue; /* corrupt? */
2413                email_end[1] = '\0';
2414                tz = strtol(message + 1, NULL, 10);
2415                if (message[6] != '\t')
2416                        message += 6;
2417                else
2418                        message += 7;
2419                ret = fn(osha1, nsha1, sb.buf + 82, timestamp, tz, message,
2420                         cb_data);
2421                if (ret)
2422                        break;
2423        }
2424        fclose(logfp);
2425        strbuf_release(&sb);
2426        return ret;
2427}
2428
2429int for_each_reflog_ent(const char *refname, each_reflog_ent_fn fn, void *cb_data)
2430{
2431        return for_each_recent_reflog_ent(refname, fn, 0, cb_data);
2432}
2433
2434/*
2435 * Call fn for each reflog in the namespace indicated by name.  name
2436 * must be empty or end with '/'.  Name will be used as a scratch
2437 * space, but its contents will be restored before return.
2438 */
2439static int do_for_each_reflog(struct strbuf *name, each_ref_fn fn, void *cb_data)
2440{
2441        DIR *d = opendir(git_path("logs/%s", name->buf));
2442        int retval = 0;
2443        struct dirent *de;
2444        int oldlen = name->len;
2445
2446        if (!d)
2447                return name->len ? errno : 0;
2448
2449        while ((de = readdir(d)) != NULL) {
2450                struct stat st;
2451
2452                if (de->d_name[0] == '.')
2453                        continue;
2454                if (has_extension(de->d_name, ".lock"))
2455                        continue;
2456                strbuf_addstr(name, de->d_name);
2457                if (stat(git_path("logs/%s", name->buf), &st) < 0) {
2458                        ; /* silently ignore */
2459                } else {
2460                        if (S_ISDIR(st.st_mode)) {
2461                                strbuf_addch(name, '/');
2462                                retval = do_for_each_reflog(name, fn, cb_data);
2463                        } else {
2464                                unsigned char sha1[20];
2465                                if (read_ref_full(name->buf, sha1, 0, NULL))
2466                                        retval = error("bad ref for %s", name->buf);
2467                                else
2468                                        retval = fn(name->buf, sha1, 0, cb_data);
2469                        }
2470                        if (retval)
2471                                break;
2472                }
2473                strbuf_setlen(name, oldlen);
2474        }
2475        closedir(d);
2476        return retval;
2477}
2478
2479int for_each_reflog(each_ref_fn fn, void *cb_data)
2480{
2481        int retval;
2482        struct strbuf name;
2483        strbuf_init(&name, PATH_MAX);
2484        retval = do_for_each_reflog(&name, fn, cb_data);
2485        strbuf_release(&name);
2486        return retval;
2487}
2488
2489int update_ref(const char *action, const char *refname,
2490                const unsigned char *sha1, const unsigned char *oldval,
2491                int flags, enum action_on_err onerr)
2492{
2493        static struct ref_lock *lock;
2494        lock = lock_any_ref_for_update(refname, oldval, flags);
2495        if (!lock) {
2496                const char *str = "Cannot lock the ref '%s'.";
2497                switch (onerr) {
2498                case MSG_ON_ERR: error(str, refname); break;
2499                case DIE_ON_ERR: die(str, refname); break;
2500                case QUIET_ON_ERR: break;
2501                }
2502                return 1;
2503        }
2504        if (write_ref_sha1(lock, sha1, action) < 0) {
2505                const char *str = "Cannot update the ref '%s'.";
2506                switch (onerr) {
2507                case MSG_ON_ERR: error(str, refname); break;
2508                case DIE_ON_ERR: die(str, refname); break;
2509                case QUIET_ON_ERR: break;
2510                }
2511                return 1;
2512        }
2513        return 0;
2514}
2515
2516struct ref *find_ref_by_name(const struct ref *list, const char *name)
2517{
2518        for ( ; list; list = list->next)
2519                if (!strcmp(list->name, name))
2520                        return (struct ref *)list;
2521        return NULL;
2522}
2523
2524/*
2525 * generate a format suitable for scanf from a ref_rev_parse_rules
2526 * rule, that is replace the "%.*s" spec with a "%s" spec
2527 */
2528static void gen_scanf_fmt(char *scanf_fmt, const char *rule)
2529{
2530        char *spec;
2531
2532        spec = strstr(rule, "%.*s");
2533        if (!spec || strstr(spec + 4, "%.*s"))
2534                die("invalid rule in ref_rev_parse_rules: %s", rule);
2535
2536        /* copy all until spec */
2537        strncpy(scanf_fmt, rule, spec - rule);
2538        scanf_fmt[spec - rule] = '\0';
2539        /* copy new spec */
2540        strcat(scanf_fmt, "%s");
2541        /* copy remaining rule */
2542        strcat(scanf_fmt, spec + 4);
2543
2544        return;
2545}
2546
2547char *shorten_unambiguous_ref(const char *refname, int strict)
2548{
2549        int i;
2550        static char **scanf_fmts;
2551        static int nr_rules;
2552        char *short_name;
2553
2554        /* pre generate scanf formats from ref_rev_parse_rules[] */
2555        if (!nr_rules) {
2556                size_t total_len = 0;
2557
2558                /* the rule list is NULL terminated, count them first */
2559                for (; ref_rev_parse_rules[nr_rules]; nr_rules++)
2560                        /* no +1 because strlen("%s") < strlen("%.*s") */
2561                        total_len += strlen(ref_rev_parse_rules[nr_rules]);
2562
2563                scanf_fmts = xmalloc(nr_rules * sizeof(char *) + total_len);
2564
2565                total_len = 0;
2566                for (i = 0; i < nr_rules; i++) {
2567                        scanf_fmts[i] = (char *)&scanf_fmts[nr_rules]
2568                                        + total_len;
2569                        gen_scanf_fmt(scanf_fmts[i], ref_rev_parse_rules[i]);
2570                        total_len += strlen(ref_rev_parse_rules[i]);
2571                }
2572        }
2573
2574        /* bail out if there are no rules */
2575        if (!nr_rules)
2576                return xstrdup(refname);
2577
2578        /* buffer for scanf result, at most refname must fit */
2579        short_name = xstrdup(refname);
2580
2581        /* skip first rule, it will always match */
2582        for (i = nr_rules - 1; i > 0 ; --i) {
2583                int j;
2584                int rules_to_fail = i;
2585                int short_name_len;
2586
2587                if (1 != sscanf(refname, scanf_fmts[i], short_name))
2588                        continue;
2589
2590                short_name_len = strlen(short_name);
2591
2592                /*
2593                 * in strict mode, all (except the matched one) rules
2594                 * must fail to resolve to a valid non-ambiguous ref
2595                 */
2596                if (strict)
2597                        rules_to_fail = nr_rules;
2598
2599                /*
2600                 * check if the short name resolves to a valid ref,
2601                 * but use only rules prior to the matched one
2602                 */
2603                for (j = 0; j < rules_to_fail; j++) {
2604                        const char *rule = ref_rev_parse_rules[j];
2605                        char refname[PATH_MAX];
2606
2607                        /* skip matched rule */
2608                        if (i == j)
2609                                continue;
2610
2611                        /*
2612                         * the short name is ambiguous, if it resolves
2613                         * (with this previous rule) to a valid ref
2614                         * read_ref() returns 0 on success
2615                         */
2616                        mksnpath(refname, sizeof(refname),
2617                                 rule, short_name_len, short_name);
2618                        if (ref_exists(refname))
2619                                break;
2620                }
2621
2622                /*
2623                 * short name is non-ambiguous if all previous rules
2624                 * haven't resolved to a valid ref
2625                 */
2626                if (j == rules_to_fail)
2627                        return short_name;
2628        }
2629
2630        free(short_name);
2631        return xstrdup(refname);
2632}