ccbd04a0351d5810b2cc5b6b726e2f54cacdd3e8
   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
 532/*
 533 * current_ref is a performance hack: when iterating over references
 534 * using the for_each_ref*() functions, current_ref is set to the
 535 * current reference's entry before calling the callback function.  If
 536 * the callback function calls peel_ref(), then peel_ref() first
 537 * checks whether the reference to be peeled is the current reference
 538 * (it usually is) and if so, returns that reference's peeled version
 539 * if it is available.  This avoids a refname lookup in a common case.
 540 */
 541static struct ref_entry *current_ref;
 542
 543/*
 544 * Handle one reference in a do_for_each_ref*()-style iteration.
 545 */
 546static int do_one_ref(const char *base, each_ref_fn fn, int trim,
 547                      int flags, void *cb_data, struct ref_entry *entry)
 548{
 549        int retval;
 550        if (prefixcmp(entry->name, base))
 551                return 0;
 552
 553        if (!(flags & DO_FOR_EACH_INCLUDE_BROKEN)) {
 554                if (entry->flag & REF_ISBROKEN)
 555                        return 0; /* ignore broken refs e.g. dangling symref */
 556                if (!has_sha1_file(entry->u.value.sha1)) {
 557                        error("%s does not point to a valid object!", entry->name);
 558                        return 0;
 559                }
 560        }
 561        current_ref = entry;
 562        retval = fn(entry->name + trim, entry->u.value.sha1, entry->flag, cb_data);
 563        current_ref = NULL;
 564        return retval;
 565}
 566
 567/*
 568 * Call fn for each reference in dir that has index in the range
 569 * offset <= index < dir->nr.  Recurse into subdirectories that are in
 570 * that index range, sorting them before iterating.  This function
 571 * does not sort dir itself; it should be sorted beforehand.
 572 */
 573static int do_for_each_ref_in_dir(struct ref_dir *dir, int offset,
 574                                  const char *base,
 575                                  each_ref_fn fn, int trim, int flags, void *cb_data)
 576{
 577        int i;
 578        assert(dir->sorted == dir->nr);
 579        for (i = offset; i < dir->nr; i++) {
 580                struct ref_entry *entry = dir->entries[i];
 581                int retval;
 582                if (entry->flag & REF_DIR) {
 583                        struct ref_dir *subdir = get_ref_dir(entry);
 584                        sort_ref_dir(subdir);
 585                        retval = do_for_each_ref_in_dir(subdir, 0,
 586                                                        base, fn, trim, flags, cb_data);
 587                } else {
 588                        retval = do_one_ref(base, fn, trim, flags, cb_data, entry);
 589                }
 590                if (retval)
 591                        return retval;
 592        }
 593        return 0;
 594}
 595
 596/*
 597 * Call fn for each reference in the union of dir1 and dir2, in order
 598 * by refname.  Recurse into subdirectories.  If a value entry appears
 599 * in both dir1 and dir2, then only process the version that is in
 600 * dir2.  The input dirs must already be sorted, but subdirs will be
 601 * sorted as needed.
 602 */
 603static int do_for_each_ref_in_dirs(struct ref_dir *dir1,
 604                                   struct ref_dir *dir2,
 605                                   const char *base, each_ref_fn fn, int trim,
 606                                   int flags, void *cb_data)
 607{
 608        int retval;
 609        int i1 = 0, i2 = 0;
 610
 611        assert(dir1->sorted == dir1->nr);
 612        assert(dir2->sorted == dir2->nr);
 613        while (1) {
 614                struct ref_entry *e1, *e2;
 615                int cmp;
 616                if (i1 == dir1->nr) {
 617                        return do_for_each_ref_in_dir(dir2, i2,
 618                                                      base, fn, trim, flags, cb_data);
 619                }
 620                if (i2 == dir2->nr) {
 621                        return do_for_each_ref_in_dir(dir1, i1,
 622                                                      base, fn, trim, flags, cb_data);
 623                }
 624                e1 = dir1->entries[i1];
 625                e2 = dir2->entries[i2];
 626                cmp = strcmp(e1->name, e2->name);
 627                if (cmp == 0) {
 628                        if ((e1->flag & REF_DIR) && (e2->flag & REF_DIR)) {
 629                                /* Both are directories; descend them in parallel. */
 630                                struct ref_dir *subdir1 = get_ref_dir(e1);
 631                                struct ref_dir *subdir2 = get_ref_dir(e2);
 632                                sort_ref_dir(subdir1);
 633                                sort_ref_dir(subdir2);
 634                                retval = do_for_each_ref_in_dirs(
 635                                                subdir1, subdir2,
 636                                                base, fn, trim, flags, cb_data);
 637                                i1++;
 638                                i2++;
 639                        } else if (!(e1->flag & REF_DIR) && !(e2->flag & REF_DIR)) {
 640                                /* Both are references; ignore the one from dir1. */
 641                                retval = do_one_ref(base, fn, trim, flags, cb_data, e2);
 642                                i1++;
 643                                i2++;
 644                        } else {
 645                                die("conflict between reference and directory: %s",
 646                                    e1->name);
 647                        }
 648                } else {
 649                        struct ref_entry *e;
 650                        if (cmp < 0) {
 651                                e = e1;
 652                                i1++;
 653                        } else {
 654                                e = e2;
 655                                i2++;
 656                        }
 657                        if (e->flag & REF_DIR) {
 658                                struct ref_dir *subdir = get_ref_dir(e);
 659                                sort_ref_dir(subdir);
 660                                retval = do_for_each_ref_in_dir(
 661                                                subdir, 0,
 662                                                base, fn, trim, flags, cb_data);
 663                        } else {
 664                                retval = do_one_ref(base, fn, trim, flags, cb_data, e);
 665                        }
 666                }
 667                if (retval)
 668                        return retval;
 669        }
 670        if (i1 < dir1->nr)
 671                return do_for_each_ref_in_dir(dir1, i1,
 672                                              base, fn, trim, flags, cb_data);
 673        if (i2 < dir2->nr)
 674                return do_for_each_ref_in_dir(dir2, i2,
 675                                              base, fn, trim, flags, cb_data);
 676        return 0;
 677}
 678
 679/*
 680 * Return true iff refname1 and refname2 conflict with each other.
 681 * Two reference names conflict if one of them exactly matches the
 682 * leading components of the other; e.g., "foo/bar" conflicts with
 683 * both "foo" and with "foo/bar/baz" but not with "foo/bar" or
 684 * "foo/barbados".
 685 */
 686static int names_conflict(const char *refname1, const char *refname2)
 687{
 688        for (; *refname1 && *refname1 == *refname2; refname1++, refname2++)
 689                ;
 690        return (*refname1 == '\0' && *refname2 == '/')
 691                || (*refname1 == '/' && *refname2 == '\0');
 692}
 693
 694struct name_conflict_cb {
 695        const char *refname;
 696        const char *oldrefname;
 697        const char *conflicting_refname;
 698};
 699
 700static int name_conflict_fn(const char *existingrefname, const unsigned char *sha1,
 701                            int flags, void *cb_data)
 702{
 703        struct name_conflict_cb *data = (struct name_conflict_cb *)cb_data;
 704        if (data->oldrefname && !strcmp(data->oldrefname, existingrefname))
 705                return 0;
 706        if (names_conflict(data->refname, existingrefname)) {
 707                data->conflicting_refname = existingrefname;
 708                return 1;
 709        }
 710        return 0;
 711}
 712
 713/*
 714 * Return true iff a reference named refname could be created without
 715 * conflicting with the name of an existing reference in array.  If
 716 * oldrefname is non-NULL, ignore potential conflicts with oldrefname
 717 * (e.g., because oldrefname is scheduled for deletion in the same
 718 * operation).
 719 */
 720static int is_refname_available(const char *refname, const char *oldrefname,
 721                                struct ref_dir *dir)
 722{
 723        struct name_conflict_cb data;
 724        data.refname = refname;
 725        data.oldrefname = oldrefname;
 726        data.conflicting_refname = NULL;
 727
 728        sort_ref_dir(dir);
 729        if (do_for_each_ref_in_dir(dir, 0, "", name_conflict_fn,
 730                                   0, DO_FOR_EACH_INCLUDE_BROKEN,
 731                                   &data)) {
 732                error("'%s' exists; cannot create '%s'",
 733                      data.conflicting_refname, refname);
 734                return 0;
 735        }
 736        return 1;
 737}
 738
 739/*
 740 * Future: need to be in "struct repository"
 741 * when doing a full libification.
 742 */
 743static struct ref_cache {
 744        struct ref_cache *next;
 745        struct ref_entry *loose;
 746        struct ref_entry *packed;
 747        /* The submodule name, or "" for the main repo. */
 748        char name[FLEX_ARRAY];
 749} *ref_cache;
 750
 751static void clear_packed_ref_cache(struct ref_cache *refs)
 752{
 753        if (refs->packed) {
 754                free_ref_entry(refs->packed);
 755                refs->packed = NULL;
 756        }
 757}
 758
 759static void clear_loose_ref_cache(struct ref_cache *refs)
 760{
 761        if (refs->loose) {
 762                free_ref_entry(refs->loose);
 763                refs->loose = NULL;
 764        }
 765}
 766
 767static struct ref_cache *create_ref_cache(const char *submodule)
 768{
 769        int len;
 770        struct ref_cache *refs;
 771        if (!submodule)
 772                submodule = "";
 773        len = strlen(submodule) + 1;
 774        refs = xcalloc(1, sizeof(struct ref_cache) + len);
 775        memcpy(refs->name, submodule, len);
 776        return refs;
 777}
 778
 779/*
 780 * Return a pointer to a ref_cache for the specified submodule. For
 781 * the main repository, use submodule==NULL. The returned structure
 782 * will be allocated and initialized but not necessarily populated; it
 783 * should not be freed.
 784 */
 785static struct ref_cache *get_ref_cache(const char *submodule)
 786{
 787        struct ref_cache *refs = ref_cache;
 788        if (!submodule)
 789                submodule = "";
 790        while (refs) {
 791                if (!strcmp(submodule, refs->name))
 792                        return refs;
 793                refs = refs->next;
 794        }
 795
 796        refs = create_ref_cache(submodule);
 797        refs->next = ref_cache;
 798        ref_cache = refs;
 799        return refs;
 800}
 801
 802void invalidate_ref_cache(const char *submodule)
 803{
 804        struct ref_cache *refs = get_ref_cache(submodule);
 805        clear_packed_ref_cache(refs);
 806        clear_loose_ref_cache(refs);
 807}
 808
 809/*
 810 * Parse one line from a packed-refs file.  Write the SHA1 to sha1.
 811 * Return a pointer to the refname within the line (null-terminated),
 812 * or NULL if there was a problem.
 813 */
 814static const char *parse_ref_line(char *line, unsigned char *sha1)
 815{
 816        /*
 817         * 42: the answer to everything.
 818         *
 819         * In this case, it happens to be the answer to
 820         *  40 (length of sha1 hex representation)
 821         *  +1 (space in between hex and name)
 822         *  +1 (newline at the end of the line)
 823         */
 824        int len = strlen(line) - 42;
 825
 826        if (len <= 0)
 827                return NULL;
 828        if (get_sha1_hex(line, sha1) < 0)
 829                return NULL;
 830        if (!isspace(line[40]))
 831                return NULL;
 832        line += 41;
 833        if (isspace(*line))
 834                return NULL;
 835        if (line[len] != '\n')
 836                return NULL;
 837        line[len] = 0;
 838
 839        return line;
 840}
 841
 842/*
 843 * Read f, which is a packed-refs file, into dir.
 844 *
 845 * A comment line of the form "# pack-refs with: " may contain zero or
 846 * more traits. We interpret the traits as follows:
 847 *
 848 *   No traits:
 849 *
 850 *      Probably no references are peeled. But if the file contains a
 851 *      peeled value for a reference, we will use it.
 852 *
 853 *   peeled:
 854 *
 855 *      References under "refs/tags/", if they *can* be peeled, *are*
 856 *      peeled in this file. References outside of "refs/tags/" are
 857 *      probably not peeled even if they could have been, but if we find
 858 *      a peeled value for such a reference we will use it.
 859 *
 860 *   fully-peeled:
 861 *
 862 *      All references in the file that can be peeled are peeled.
 863 *      Inversely (and this is more important), any references in the
 864 *      file for which no peeled value is recorded is not peelable. This
 865 *      trait should typically be written alongside "peeled" for
 866 *      compatibility with older clients, but we do not require it
 867 *      (i.e., "peeled" is a no-op if "fully-peeled" is set).
 868 */
 869static void read_packed_refs(FILE *f, struct ref_dir *dir)
 870{
 871        struct ref_entry *last = NULL;
 872        char refline[PATH_MAX];
 873        enum { PEELED_NONE, PEELED_TAGS, PEELED_FULLY } peeled = PEELED_NONE;
 874
 875        while (fgets(refline, sizeof(refline), f)) {
 876                unsigned char sha1[20];
 877                const char *refname;
 878                static const char header[] = "# pack-refs with:";
 879
 880                if (!strncmp(refline, header, sizeof(header)-1)) {
 881                        const char *traits = refline + sizeof(header) - 1;
 882                        if (strstr(traits, " fully-peeled "))
 883                                peeled = PEELED_FULLY;
 884                        else if (strstr(traits, " peeled "))
 885                                peeled = PEELED_TAGS;
 886                        /* perhaps other traits later as well */
 887                        continue;
 888                }
 889
 890                refname = parse_ref_line(refline, sha1);
 891                if (refname) {
 892                        last = create_ref_entry(refname, sha1, REF_ISPACKED, 1);
 893                        if (peeled == PEELED_FULLY ||
 894                            (peeled == PEELED_TAGS && !prefixcmp(refname, "refs/tags/")))
 895                                last->flag |= REF_KNOWS_PEELED;
 896                        add_ref(dir, last);
 897                        continue;
 898                }
 899                if (last &&
 900                    refline[0] == '^' &&
 901                    strlen(refline) == 42 &&
 902                    refline[41] == '\n' &&
 903                    !get_sha1_hex(refline + 1, sha1)) {
 904                        hashcpy(last->u.value.peeled, sha1);
 905                        /*
 906                         * Regardless of what the file header said,
 907                         * we definitely know the value of *this*
 908                         * reference:
 909                         */
 910                        last->flag |= REF_KNOWS_PEELED;
 911                }
 912        }
 913}
 914
 915static struct ref_dir *get_packed_refs(struct ref_cache *refs)
 916{
 917        if (!refs->packed) {
 918                const char *packed_refs_file;
 919                FILE *f;
 920
 921                refs->packed = create_dir_entry(refs, "", 0, 0);
 922                if (*refs->name)
 923                        packed_refs_file = git_path_submodule(refs->name, "packed-refs");
 924                else
 925                        packed_refs_file = git_path("packed-refs");
 926                f = fopen(packed_refs_file, "r");
 927                if (f) {
 928                        read_packed_refs(f, get_ref_dir(refs->packed));
 929                        fclose(f);
 930                }
 931        }
 932        return get_ref_dir(refs->packed);
 933}
 934
 935void add_packed_ref(const char *refname, const unsigned char *sha1)
 936{
 937        add_ref(get_packed_refs(get_ref_cache(NULL)),
 938                        create_ref_entry(refname, sha1, REF_ISPACKED, 1));
 939}
 940
 941/*
 942 * Read the loose references from the namespace dirname into dir
 943 * (without recursing).  dirname must end with '/'.  dir must be the
 944 * directory entry corresponding to dirname.
 945 */
 946static void read_loose_refs(const char *dirname, struct ref_dir *dir)
 947{
 948        struct ref_cache *refs = dir->ref_cache;
 949        DIR *d;
 950        const char *path;
 951        struct dirent *de;
 952        int dirnamelen = strlen(dirname);
 953        struct strbuf refname;
 954
 955        if (*refs->name)
 956                path = git_path_submodule(refs->name, "%s", dirname);
 957        else
 958                path = git_path("%s", dirname);
 959
 960        d = opendir(path);
 961        if (!d)
 962                return;
 963
 964        strbuf_init(&refname, dirnamelen + 257);
 965        strbuf_add(&refname, dirname, dirnamelen);
 966
 967        while ((de = readdir(d)) != NULL) {
 968                unsigned char sha1[20];
 969                struct stat st;
 970                int flag;
 971                const char *refdir;
 972
 973                if (de->d_name[0] == '.')
 974                        continue;
 975                if (has_extension(de->d_name, ".lock"))
 976                        continue;
 977                strbuf_addstr(&refname, de->d_name);
 978                refdir = *refs->name
 979                        ? git_path_submodule(refs->name, "%s", refname.buf)
 980                        : git_path("%s", refname.buf);
 981                if (stat(refdir, &st) < 0) {
 982                        ; /* silently ignore */
 983                } else if (S_ISDIR(st.st_mode)) {
 984                        strbuf_addch(&refname, '/');
 985                        add_entry_to_dir(dir,
 986                                         create_dir_entry(refs, refname.buf,
 987                                                          refname.len, 1));
 988                } else {
 989                        if (*refs->name) {
 990                                hashclr(sha1);
 991                                flag = 0;
 992                                if (resolve_gitlink_ref(refs->name, refname.buf, sha1) < 0) {
 993                                        hashclr(sha1);
 994                                        flag |= REF_ISBROKEN;
 995                                }
 996                        } else if (read_ref_full(refname.buf, sha1, 1, &flag)) {
 997                                hashclr(sha1);
 998                                flag |= REF_ISBROKEN;
 999                        }
1000                        add_entry_to_dir(dir,
1001                                         create_ref_entry(refname.buf, sha1, flag, 1));
1002                }
1003                strbuf_setlen(&refname, dirnamelen);
1004        }
1005        strbuf_release(&refname);
1006        closedir(d);
1007}
1008
1009static struct ref_dir *get_loose_refs(struct ref_cache *refs)
1010{
1011        if (!refs->loose) {
1012                /*
1013                 * Mark the top-level directory complete because we
1014                 * are about to read the only subdirectory that can
1015                 * hold references:
1016                 */
1017                refs->loose = create_dir_entry(refs, "", 0, 0);
1018                /*
1019                 * Create an incomplete entry for "refs/":
1020                 */
1021                add_entry_to_dir(get_ref_dir(refs->loose),
1022                                 create_dir_entry(refs, "refs/", 5, 1));
1023        }
1024        return get_ref_dir(refs->loose);
1025}
1026
1027/* We allow "recursive" symbolic refs. Only within reason, though */
1028#define MAXDEPTH 5
1029#define MAXREFLEN (1024)
1030
1031/*
1032 * Called by resolve_gitlink_ref_recursive() after it failed to read
1033 * from the loose refs in ref_cache refs. Find <refname> in the
1034 * packed-refs file for the submodule.
1035 */
1036static int resolve_gitlink_packed_ref(struct ref_cache *refs,
1037                                      const char *refname, unsigned char *sha1)
1038{
1039        struct ref_entry *ref;
1040        struct ref_dir *dir = get_packed_refs(refs);
1041
1042        ref = find_ref(dir, refname);
1043        if (ref == NULL)
1044                return -1;
1045
1046        memcpy(sha1, ref->u.value.sha1, 20);
1047        return 0;
1048}
1049
1050static int resolve_gitlink_ref_recursive(struct ref_cache *refs,
1051                                         const char *refname, unsigned char *sha1,
1052                                         int recursion)
1053{
1054        int fd, len;
1055        char buffer[128], *p;
1056        char *path;
1057
1058        if (recursion > MAXDEPTH || strlen(refname) > MAXREFLEN)
1059                return -1;
1060        path = *refs->name
1061                ? git_path_submodule(refs->name, "%s", refname)
1062                : git_path("%s", refname);
1063        fd = open(path, O_RDONLY);
1064        if (fd < 0)
1065                return resolve_gitlink_packed_ref(refs, refname, sha1);
1066
1067        len = read(fd, buffer, sizeof(buffer)-1);
1068        close(fd);
1069        if (len < 0)
1070                return -1;
1071        while (len && isspace(buffer[len-1]))
1072                len--;
1073        buffer[len] = 0;
1074
1075        /* Was it a detached head or an old-fashioned symlink? */
1076        if (!get_sha1_hex(buffer, sha1))
1077                return 0;
1078
1079        /* Symref? */
1080        if (strncmp(buffer, "ref:", 4))
1081                return -1;
1082        p = buffer + 4;
1083        while (isspace(*p))
1084                p++;
1085
1086        return resolve_gitlink_ref_recursive(refs, p, sha1, recursion+1);
1087}
1088
1089int resolve_gitlink_ref(const char *path, const char *refname, unsigned char *sha1)
1090{
1091        int len = strlen(path), retval;
1092        char *submodule;
1093        struct ref_cache *refs;
1094
1095        while (len && path[len-1] == '/')
1096                len--;
1097        if (!len)
1098                return -1;
1099        submodule = xstrndup(path, len);
1100        refs = get_ref_cache(submodule);
1101        free(submodule);
1102
1103        retval = resolve_gitlink_ref_recursive(refs, refname, sha1, 0);
1104        return retval;
1105}
1106
1107/*
1108 * Try to read ref from the packed references.  On success, set sha1
1109 * and return 0; otherwise, return -1.
1110 */
1111static int get_packed_ref(const char *refname, unsigned char *sha1)
1112{
1113        struct ref_dir *packed = get_packed_refs(get_ref_cache(NULL));
1114        struct ref_entry *entry = find_ref(packed, refname);
1115        if (entry) {
1116                hashcpy(sha1, entry->u.value.sha1);
1117                return 0;
1118        }
1119        return -1;
1120}
1121
1122const char *resolve_ref_unsafe(const char *refname, unsigned char *sha1, int reading, int *flag)
1123{
1124        int depth = MAXDEPTH;
1125        ssize_t len;
1126        char buffer[256];
1127        static char refname_buffer[256];
1128
1129        if (flag)
1130                *flag = 0;
1131
1132        if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL))
1133                return NULL;
1134
1135        for (;;) {
1136                char path[PATH_MAX];
1137                struct stat st;
1138                char *buf;
1139                int fd;
1140
1141                if (--depth < 0)
1142                        return NULL;
1143
1144                git_snpath(path, sizeof(path), "%s", refname);
1145
1146                if (lstat(path, &st) < 0) {
1147                        if (errno != ENOENT)
1148                                return NULL;
1149                        /*
1150                         * The loose reference file does not exist;
1151                         * check for a packed reference.
1152                         */
1153                        if (!get_packed_ref(refname, sha1)) {
1154                                if (flag)
1155                                        *flag |= REF_ISPACKED;
1156                                return refname;
1157                        }
1158                        /* The reference is not a packed reference, either. */
1159                        if (reading) {
1160                                return NULL;
1161                        } else {
1162                                hashclr(sha1);
1163                                return refname;
1164                        }
1165                }
1166
1167                /* Follow "normalized" - ie "refs/.." symlinks by hand */
1168                if (S_ISLNK(st.st_mode)) {
1169                        len = readlink(path, buffer, sizeof(buffer)-1);
1170                        if (len < 0)
1171                                return NULL;
1172                        buffer[len] = 0;
1173                        if (!prefixcmp(buffer, "refs/") &&
1174                                        !check_refname_format(buffer, 0)) {
1175                                strcpy(refname_buffer, buffer);
1176                                refname = refname_buffer;
1177                                if (flag)
1178                                        *flag |= REF_ISSYMREF;
1179                                continue;
1180                        }
1181                }
1182
1183                /* Is it a directory? */
1184                if (S_ISDIR(st.st_mode)) {
1185                        errno = EISDIR;
1186                        return NULL;
1187                }
1188
1189                /*
1190                 * Anything else, just open it and try to use it as
1191                 * a ref
1192                 */
1193                fd = open(path, O_RDONLY);
1194                if (fd < 0)
1195                        return NULL;
1196                len = read_in_full(fd, buffer, sizeof(buffer)-1);
1197                close(fd);
1198                if (len < 0)
1199                        return NULL;
1200                while (len && isspace(buffer[len-1]))
1201                        len--;
1202                buffer[len] = '\0';
1203
1204                /*
1205                 * Is it a symbolic ref?
1206                 */
1207                if (prefixcmp(buffer, "ref:"))
1208                        break;
1209                if (flag)
1210                        *flag |= REF_ISSYMREF;
1211                buf = buffer + 4;
1212                while (isspace(*buf))
1213                        buf++;
1214                if (check_refname_format(buf, REFNAME_ALLOW_ONELEVEL)) {
1215                        if (flag)
1216                                *flag |= REF_ISBROKEN;
1217                        return NULL;
1218                }
1219                refname = strcpy(refname_buffer, buf);
1220        }
1221        /* Please note that FETCH_HEAD has a second line containing other data. */
1222        if (get_sha1_hex(buffer, sha1) || (buffer[40] != '\0' && !isspace(buffer[40]))) {
1223                if (flag)
1224                        *flag |= REF_ISBROKEN;
1225                return NULL;
1226        }
1227        return refname;
1228}
1229
1230char *resolve_refdup(const char *ref, unsigned char *sha1, int reading, int *flag)
1231{
1232        const char *ret = resolve_ref_unsafe(ref, sha1, reading, flag);
1233        return ret ? xstrdup(ret) : NULL;
1234}
1235
1236/* The argument to filter_refs */
1237struct ref_filter {
1238        const char *pattern;
1239        each_ref_fn *fn;
1240        void *cb_data;
1241};
1242
1243int read_ref_full(const char *refname, unsigned char *sha1, int reading, int *flags)
1244{
1245        if (resolve_ref_unsafe(refname, sha1, reading, flags))
1246                return 0;
1247        return -1;
1248}
1249
1250int read_ref(const char *refname, unsigned char *sha1)
1251{
1252        return read_ref_full(refname, sha1, 1, NULL);
1253}
1254
1255int ref_exists(const char *refname)
1256{
1257        unsigned char sha1[20];
1258        return !!resolve_ref_unsafe(refname, sha1, 1, NULL);
1259}
1260
1261static int filter_refs(const char *refname, const unsigned char *sha1, int flags,
1262                       void *data)
1263{
1264        struct ref_filter *filter = (struct ref_filter *)data;
1265        if (fnmatch(filter->pattern, refname, 0))
1266                return 0;
1267        return filter->fn(refname, sha1, flags, filter->cb_data);
1268}
1269
1270int peel_ref(const char *refname, unsigned char *sha1)
1271{
1272        int flag;
1273        unsigned char base[20];
1274        struct object *o;
1275
1276        if (current_ref && (current_ref->name == refname
1277                || !strcmp(current_ref->name, refname))) {
1278                if (current_ref->flag & REF_KNOWS_PEELED) {
1279                        if (is_null_sha1(current_ref->u.value.peeled))
1280                            return -1;
1281                        hashcpy(sha1, current_ref->u.value.peeled);
1282                        return 0;
1283                }
1284                hashcpy(base, current_ref->u.value.sha1);
1285                goto fallback;
1286        }
1287
1288        if (read_ref_full(refname, base, 1, &flag))
1289                return -1;
1290
1291        if ((flag & REF_ISPACKED)) {
1292                struct ref_dir *dir = get_packed_refs(get_ref_cache(NULL));
1293                struct ref_entry *r = find_ref(dir, refname);
1294
1295                if (r != NULL && r->flag & REF_KNOWS_PEELED) {
1296                        hashcpy(sha1, r->u.value.peeled);
1297                        return 0;
1298                }
1299        }
1300
1301fallback:
1302        o = lookup_unknown_object(base);
1303        if (o->type == OBJ_NONE) {
1304                int type = sha1_object_info(base, NULL);
1305                if (type < 0)
1306                        return -1;
1307                o->type = type;
1308        }
1309
1310        if (o->type == OBJ_TAG) {
1311                o = deref_tag_noverify(o);
1312                if (o) {
1313                        hashcpy(sha1, o->sha1);
1314                        return 0;
1315                }
1316        }
1317        return -1;
1318}
1319
1320struct warn_if_dangling_data {
1321        FILE *fp;
1322        const char *refname;
1323        const char *msg_fmt;
1324};
1325
1326static int warn_if_dangling_symref(const char *refname, const unsigned char *sha1,
1327                                   int flags, void *cb_data)
1328{
1329        struct warn_if_dangling_data *d = cb_data;
1330        const char *resolves_to;
1331        unsigned char junk[20];
1332
1333        if (!(flags & REF_ISSYMREF))
1334                return 0;
1335
1336        resolves_to = resolve_ref_unsafe(refname, junk, 0, NULL);
1337        if (!resolves_to || strcmp(resolves_to, d->refname))
1338                return 0;
1339
1340        fprintf(d->fp, d->msg_fmt, refname);
1341        fputc('\n', d->fp);
1342        return 0;
1343}
1344
1345void warn_dangling_symref(FILE *fp, const char *msg_fmt, const char *refname)
1346{
1347        struct warn_if_dangling_data data;
1348
1349        data.fp = fp;
1350        data.refname = refname;
1351        data.msg_fmt = msg_fmt;
1352        for_each_rawref(warn_if_dangling_symref, &data);
1353}
1354
1355/*
1356 * Call fn for each reference in the specified submodule for which the
1357 * refname begins with base.  If trim is non-zero, then trim that many
1358 * characters off the beginning of each refname before passing the
1359 * refname to fn.  flags can be DO_FOR_EACH_INCLUDE_BROKEN to include
1360 * broken references in the iteration.  If fn ever returns a non-zero
1361 * value, stop the iteration and return that value; otherwise, return
1362 * 0.
1363 */
1364static int do_for_each_ref(const char *submodule, const char *base, each_ref_fn fn,
1365                           int trim, int flags, void *cb_data)
1366{
1367        struct ref_cache *refs = get_ref_cache(submodule);
1368        struct ref_dir *packed_dir = get_packed_refs(refs);
1369        struct ref_dir *loose_dir = get_loose_refs(refs);
1370        int retval = 0;
1371
1372        if (base && *base) {
1373                packed_dir = find_containing_dir(packed_dir, base, 0);
1374                loose_dir = find_containing_dir(loose_dir, base, 0);
1375        }
1376
1377        if (packed_dir && loose_dir) {
1378                sort_ref_dir(packed_dir);
1379                sort_ref_dir(loose_dir);
1380                retval = do_for_each_ref_in_dirs(
1381                                packed_dir, loose_dir,
1382                                base, fn, trim, flags, cb_data);
1383        } else if (packed_dir) {
1384                sort_ref_dir(packed_dir);
1385                retval = do_for_each_ref_in_dir(
1386                                packed_dir, 0,
1387                                base, fn, trim, flags, cb_data);
1388        } else if (loose_dir) {
1389                sort_ref_dir(loose_dir);
1390                retval = do_for_each_ref_in_dir(
1391                                loose_dir, 0,
1392                                base, fn, trim, flags, cb_data);
1393        }
1394
1395        return retval;
1396}
1397
1398static int do_head_ref(const char *submodule, each_ref_fn fn, void *cb_data)
1399{
1400        unsigned char sha1[20];
1401        int flag;
1402
1403        if (submodule) {
1404                if (resolve_gitlink_ref(submodule, "HEAD", sha1) == 0)
1405                        return fn("HEAD", sha1, 0, cb_data);
1406
1407                return 0;
1408        }
1409
1410        if (!read_ref_full("HEAD", sha1, 1, &flag))
1411                return fn("HEAD", sha1, flag, cb_data);
1412
1413        return 0;
1414}
1415
1416int head_ref(each_ref_fn fn, void *cb_data)
1417{
1418        return do_head_ref(NULL, fn, cb_data);
1419}
1420
1421int head_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
1422{
1423        return do_head_ref(submodule, fn, cb_data);
1424}
1425
1426int for_each_ref(each_ref_fn fn, void *cb_data)
1427{
1428        return do_for_each_ref(NULL, "", fn, 0, 0, cb_data);
1429}
1430
1431int for_each_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
1432{
1433        return do_for_each_ref(submodule, "", fn, 0, 0, cb_data);
1434}
1435
1436int for_each_ref_in(const char *prefix, each_ref_fn fn, void *cb_data)
1437{
1438        return do_for_each_ref(NULL, prefix, fn, strlen(prefix), 0, cb_data);
1439}
1440
1441int for_each_ref_in_submodule(const char *submodule, const char *prefix,
1442                each_ref_fn fn, void *cb_data)
1443{
1444        return do_for_each_ref(submodule, prefix, fn, strlen(prefix), 0, cb_data);
1445}
1446
1447int for_each_tag_ref(each_ref_fn fn, void *cb_data)
1448{
1449        return for_each_ref_in("refs/tags/", fn, cb_data);
1450}
1451
1452int for_each_tag_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
1453{
1454        return for_each_ref_in_submodule(submodule, "refs/tags/", fn, cb_data);
1455}
1456
1457int for_each_branch_ref(each_ref_fn fn, void *cb_data)
1458{
1459        return for_each_ref_in("refs/heads/", fn, cb_data);
1460}
1461
1462int for_each_branch_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
1463{
1464        return for_each_ref_in_submodule(submodule, "refs/heads/", fn, cb_data);
1465}
1466
1467int for_each_remote_ref(each_ref_fn fn, void *cb_data)
1468{
1469        return for_each_ref_in("refs/remotes/", fn, cb_data);
1470}
1471
1472int for_each_remote_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
1473{
1474        return for_each_ref_in_submodule(submodule, "refs/remotes/", fn, cb_data);
1475}
1476
1477int for_each_replace_ref(each_ref_fn fn, void *cb_data)
1478{
1479        return do_for_each_ref(NULL, "refs/replace/", fn, 13, 0, cb_data);
1480}
1481
1482int head_ref_namespaced(each_ref_fn fn, void *cb_data)
1483{
1484        struct strbuf buf = STRBUF_INIT;
1485        int ret = 0;
1486        unsigned char sha1[20];
1487        int flag;
1488
1489        strbuf_addf(&buf, "%sHEAD", get_git_namespace());
1490        if (!read_ref_full(buf.buf, sha1, 1, &flag))
1491                ret = fn(buf.buf, sha1, flag, cb_data);
1492        strbuf_release(&buf);
1493
1494        return ret;
1495}
1496
1497int for_each_namespaced_ref(each_ref_fn fn, void *cb_data)
1498{
1499        struct strbuf buf = STRBUF_INIT;
1500        int ret;
1501        strbuf_addf(&buf, "%srefs/", get_git_namespace());
1502        ret = do_for_each_ref(NULL, buf.buf, fn, 0, 0, cb_data);
1503        strbuf_release(&buf);
1504        return ret;
1505}
1506
1507int for_each_glob_ref_in(each_ref_fn fn, const char *pattern,
1508        const char *prefix, void *cb_data)
1509{
1510        struct strbuf real_pattern = STRBUF_INIT;
1511        struct ref_filter filter;
1512        int ret;
1513
1514        if (!prefix && prefixcmp(pattern, "refs/"))
1515                strbuf_addstr(&real_pattern, "refs/");
1516        else if (prefix)
1517                strbuf_addstr(&real_pattern, prefix);
1518        strbuf_addstr(&real_pattern, pattern);
1519
1520        if (!has_glob_specials(pattern)) {
1521                /* Append implied '/' '*' if not present. */
1522                if (real_pattern.buf[real_pattern.len - 1] != '/')
1523                        strbuf_addch(&real_pattern, '/');
1524                /* No need to check for '*', there is none. */
1525                strbuf_addch(&real_pattern, '*');
1526        }
1527
1528        filter.pattern = real_pattern.buf;
1529        filter.fn = fn;
1530        filter.cb_data = cb_data;
1531        ret = for_each_ref(filter_refs, &filter);
1532
1533        strbuf_release(&real_pattern);
1534        return ret;
1535}
1536
1537int for_each_glob_ref(each_ref_fn fn, const char *pattern, void *cb_data)
1538{
1539        return for_each_glob_ref_in(fn, pattern, NULL, cb_data);
1540}
1541
1542int for_each_rawref(each_ref_fn fn, void *cb_data)
1543{
1544        return do_for_each_ref(NULL, "", fn, 0,
1545                               DO_FOR_EACH_INCLUDE_BROKEN, cb_data);
1546}
1547
1548const char *prettify_refname(const char *name)
1549{
1550        return name + (
1551                !prefixcmp(name, "refs/heads/") ? 11 :
1552                !prefixcmp(name, "refs/tags/") ? 10 :
1553                !prefixcmp(name, "refs/remotes/") ? 13 :
1554                0);
1555}
1556
1557const char *ref_rev_parse_rules[] = {
1558        "%.*s",
1559        "refs/%.*s",
1560        "refs/tags/%.*s",
1561        "refs/heads/%.*s",
1562        "refs/remotes/%.*s",
1563        "refs/remotes/%.*s/HEAD",
1564        NULL
1565};
1566
1567int refname_match(const char *abbrev_name, const char *full_name, const char **rules)
1568{
1569        const char **p;
1570        const int abbrev_name_len = strlen(abbrev_name);
1571
1572        for (p = rules; *p; p++) {
1573                if (!strcmp(full_name, mkpath(*p, abbrev_name_len, abbrev_name))) {
1574                        return 1;
1575                }
1576        }
1577
1578        return 0;
1579}
1580
1581static struct ref_lock *verify_lock(struct ref_lock *lock,
1582        const unsigned char *old_sha1, int mustexist)
1583{
1584        if (read_ref_full(lock->ref_name, lock->old_sha1, mustexist, NULL)) {
1585                error("Can't verify ref %s", lock->ref_name);
1586                unlock_ref(lock);
1587                return NULL;
1588        }
1589        if (hashcmp(lock->old_sha1, old_sha1)) {
1590                error("Ref %s is at %s but expected %s", lock->ref_name,
1591                        sha1_to_hex(lock->old_sha1), sha1_to_hex(old_sha1));
1592                unlock_ref(lock);
1593                return NULL;
1594        }
1595        return lock;
1596}
1597
1598static int remove_empty_directories(const char *file)
1599{
1600        /* we want to create a file but there is a directory there;
1601         * if that is an empty directory (or a directory that contains
1602         * only empty directories), remove them.
1603         */
1604        struct strbuf path;
1605        int result;
1606
1607        strbuf_init(&path, 20);
1608        strbuf_addstr(&path, file);
1609
1610        result = remove_dir_recursively(&path, REMOVE_DIR_EMPTY_ONLY);
1611
1612        strbuf_release(&path);
1613
1614        return result;
1615}
1616
1617/*
1618 * *string and *len will only be substituted, and *string returned (for
1619 * later free()ing) if the string passed in is a magic short-hand form
1620 * to name a branch.
1621 */
1622static char *substitute_branch_name(const char **string, int *len)
1623{
1624        struct strbuf buf = STRBUF_INIT;
1625        int ret = interpret_branch_name(*string, &buf);
1626
1627        if (ret == *len) {
1628                size_t size;
1629                *string = strbuf_detach(&buf, &size);
1630                *len = size;
1631                return (char *)*string;
1632        }
1633
1634        return NULL;
1635}
1636
1637int dwim_ref(const char *str, int len, unsigned char *sha1, char **ref)
1638{
1639        char *last_branch = substitute_branch_name(&str, &len);
1640        const char **p, *r;
1641        int refs_found = 0;
1642
1643        *ref = NULL;
1644        for (p = ref_rev_parse_rules; *p; p++) {
1645                char fullref[PATH_MAX];
1646                unsigned char sha1_from_ref[20];
1647                unsigned char *this_result;
1648                int flag;
1649
1650                this_result = refs_found ? sha1_from_ref : sha1;
1651                mksnpath(fullref, sizeof(fullref), *p, len, str);
1652                r = resolve_ref_unsafe(fullref, this_result, 1, &flag);
1653                if (r) {
1654                        if (!refs_found++)
1655                                *ref = xstrdup(r);
1656                        if (!warn_ambiguous_refs)
1657                                break;
1658                } else if ((flag & REF_ISSYMREF) && strcmp(fullref, "HEAD")) {
1659                        warning("ignoring dangling symref %s.", fullref);
1660                } else if ((flag & REF_ISBROKEN) && strchr(fullref, '/')) {
1661                        warning("ignoring broken ref %s.", fullref);
1662                }
1663        }
1664        free(last_branch);
1665        return refs_found;
1666}
1667
1668int dwim_log(const char *str, int len, unsigned char *sha1, char **log)
1669{
1670        char *last_branch = substitute_branch_name(&str, &len);
1671        const char **p;
1672        int logs_found = 0;
1673
1674        *log = NULL;
1675        for (p = ref_rev_parse_rules; *p; p++) {
1676                struct stat st;
1677                unsigned char hash[20];
1678                char path[PATH_MAX];
1679                const char *ref, *it;
1680
1681                mksnpath(path, sizeof(path), *p, len, str);
1682                ref = resolve_ref_unsafe(path, hash, 1, NULL);
1683                if (!ref)
1684                        continue;
1685                if (!stat(git_path("logs/%s", path), &st) &&
1686                    S_ISREG(st.st_mode))
1687                        it = path;
1688                else if (strcmp(ref, path) &&
1689                         !stat(git_path("logs/%s", ref), &st) &&
1690                         S_ISREG(st.st_mode))
1691                        it = ref;
1692                else
1693                        continue;
1694                if (!logs_found++) {
1695                        *log = xstrdup(it);
1696                        hashcpy(sha1, hash);
1697                }
1698                if (!warn_ambiguous_refs)
1699                        break;
1700        }
1701        free(last_branch);
1702        return logs_found;
1703}
1704
1705static struct ref_lock *lock_ref_sha1_basic(const char *refname,
1706                                            const unsigned char *old_sha1,
1707                                            int flags, int *type_p)
1708{
1709        char *ref_file;
1710        const char *orig_refname = refname;
1711        struct ref_lock *lock;
1712        int last_errno = 0;
1713        int type, lflags;
1714        int mustexist = (old_sha1 && !is_null_sha1(old_sha1));
1715        int missing = 0;
1716
1717        lock = xcalloc(1, sizeof(struct ref_lock));
1718        lock->lock_fd = -1;
1719
1720        refname = resolve_ref_unsafe(refname, lock->old_sha1, mustexist, &type);
1721        if (!refname && errno == EISDIR) {
1722                /* we are trying to lock foo but we used to
1723                 * have foo/bar which now does not exist;
1724                 * it is normal for the empty directory 'foo'
1725                 * to remain.
1726                 */
1727                ref_file = git_path("%s", orig_refname);
1728                if (remove_empty_directories(ref_file)) {
1729                        last_errno = errno;
1730                        error("there are still refs under '%s'", orig_refname);
1731                        goto error_return;
1732                }
1733                refname = resolve_ref_unsafe(orig_refname, lock->old_sha1, mustexist, &type);
1734        }
1735        if (type_p)
1736            *type_p = type;
1737        if (!refname) {
1738                last_errno = errno;
1739                error("unable to resolve reference %s: %s",
1740                        orig_refname, strerror(errno));
1741                goto error_return;
1742        }
1743        missing = is_null_sha1(lock->old_sha1);
1744        /* When the ref did not exist and we are creating it,
1745         * make sure there is no existing ref that is packed
1746         * whose name begins with our refname, nor a ref whose
1747         * name is a proper prefix of our refname.
1748         */
1749        if (missing &&
1750             !is_refname_available(refname, NULL, get_packed_refs(get_ref_cache(NULL)))) {
1751                last_errno = ENOTDIR;
1752                goto error_return;
1753        }
1754
1755        lock->lk = xcalloc(1, sizeof(struct lock_file));
1756
1757        lflags = LOCK_DIE_ON_ERROR;
1758        if (flags & REF_NODEREF) {
1759                refname = orig_refname;
1760                lflags |= LOCK_NODEREF;
1761        }
1762        lock->ref_name = xstrdup(refname);
1763        lock->orig_ref_name = xstrdup(orig_refname);
1764        ref_file = git_path("%s", refname);
1765        if (missing)
1766                lock->force_write = 1;
1767        if ((flags & REF_NODEREF) && (type & REF_ISSYMREF))
1768                lock->force_write = 1;
1769
1770        if (safe_create_leading_directories(ref_file)) {
1771                last_errno = errno;
1772                error("unable to create directory for %s", ref_file);
1773                goto error_return;
1774        }
1775
1776        lock->lock_fd = hold_lock_file_for_update(lock->lk, ref_file, lflags);
1777        return old_sha1 ? verify_lock(lock, old_sha1, mustexist) : lock;
1778
1779 error_return:
1780        unlock_ref(lock);
1781        errno = last_errno;
1782        return NULL;
1783}
1784
1785struct ref_lock *lock_ref_sha1(const char *refname, const unsigned char *old_sha1)
1786{
1787        char refpath[PATH_MAX];
1788        if (check_refname_format(refname, 0))
1789                return NULL;
1790        strcpy(refpath, mkpath("refs/%s", refname));
1791        return lock_ref_sha1_basic(refpath, old_sha1, 0, NULL);
1792}
1793
1794struct ref_lock *lock_any_ref_for_update(const char *refname,
1795                                         const unsigned char *old_sha1, int flags)
1796{
1797        if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL))
1798                return NULL;
1799        return lock_ref_sha1_basic(refname, old_sha1, flags, NULL);
1800}
1801
1802struct repack_without_ref_sb {
1803        const char *refname;
1804        int fd;
1805};
1806
1807static int repack_without_ref_fn(const char *refname, const unsigned char *sha1,
1808                                 int flags, void *cb_data)
1809{
1810        struct repack_without_ref_sb *data = cb_data;
1811        char line[PATH_MAX + 100];
1812        int len;
1813
1814        if (!strcmp(data->refname, refname))
1815                return 0;
1816        len = snprintf(line, sizeof(line), "%s %s\n",
1817                       sha1_to_hex(sha1), refname);
1818        /* this should not happen but just being defensive */
1819        if (len > sizeof(line))
1820                die("too long a refname '%s'", refname);
1821        write_or_die(data->fd, line, len);
1822        return 0;
1823}
1824
1825static struct lock_file packlock;
1826
1827static int repack_without_ref(const char *refname)
1828{
1829        struct repack_without_ref_sb data;
1830        struct ref_cache *refs = get_ref_cache(NULL);
1831        struct ref_dir *packed = get_packed_refs(refs);
1832        if (find_ref(packed, refname) == NULL)
1833                return 0;
1834        data.refname = refname;
1835        data.fd = hold_lock_file_for_update(&packlock, git_path("packed-refs"), 0);
1836        if (data.fd < 0) {
1837                unable_to_lock_error(git_path("packed-refs"), errno);
1838                return error("cannot delete '%s' from packed refs", refname);
1839        }
1840        clear_packed_ref_cache(refs);
1841        packed = get_packed_refs(refs);
1842        do_for_each_ref_in_dir(packed, 0, "", repack_without_ref_fn, 0, 0, &data);
1843        return commit_lock_file(&packlock);
1844}
1845
1846int delete_ref(const char *refname, const unsigned char *sha1, int delopt)
1847{
1848        struct ref_lock *lock;
1849        int err, i = 0, ret = 0, flag = 0;
1850
1851        lock = lock_ref_sha1_basic(refname, sha1, delopt, &flag);
1852        if (!lock)
1853                return 1;
1854        if (!(flag & REF_ISPACKED) || flag & REF_ISSYMREF) {
1855                /* loose */
1856                i = strlen(lock->lk->filename) - 5; /* .lock */
1857                lock->lk->filename[i] = 0;
1858                err = unlink_or_warn(lock->lk->filename);
1859                if (err && errno != ENOENT)
1860                        ret = 1;
1861
1862                lock->lk->filename[i] = '.';
1863        }
1864        /* removing the loose one could have resurrected an earlier
1865         * packed one.  Also, if it was not loose we need to repack
1866         * without it.
1867         */
1868        ret |= repack_without_ref(lock->ref_name);
1869
1870        unlink_or_warn(git_path("logs/%s", lock->ref_name));
1871        invalidate_ref_cache(NULL);
1872        unlock_ref(lock);
1873        return ret;
1874}
1875
1876/*
1877 * People using contrib's git-new-workdir have .git/logs/refs ->
1878 * /some/other/path/.git/logs/refs, and that may live on another device.
1879 *
1880 * IOW, to avoid cross device rename errors, the temporary renamed log must
1881 * live into logs/refs.
1882 */
1883#define TMP_RENAMED_LOG  "logs/refs/.tmp-renamed-log"
1884
1885int rename_ref(const char *oldrefname, const char *newrefname, const char *logmsg)
1886{
1887        unsigned char sha1[20], orig_sha1[20];
1888        int flag = 0, logmoved = 0;
1889        struct ref_lock *lock;
1890        struct stat loginfo;
1891        int log = !lstat(git_path("logs/%s", oldrefname), &loginfo);
1892        const char *symref = NULL;
1893        struct ref_cache *refs = get_ref_cache(NULL);
1894
1895        if (log && S_ISLNK(loginfo.st_mode))
1896                return error("reflog for %s is a symlink", oldrefname);
1897
1898        symref = resolve_ref_unsafe(oldrefname, orig_sha1, 1, &flag);
1899        if (flag & REF_ISSYMREF)
1900                return error("refname %s is a symbolic ref, renaming it is not supported",
1901                        oldrefname);
1902        if (!symref)
1903                return error("refname %s not found", oldrefname);
1904
1905        if (!is_refname_available(newrefname, oldrefname, get_packed_refs(refs)))
1906                return 1;
1907
1908        if (!is_refname_available(newrefname, oldrefname, get_loose_refs(refs)))
1909                return 1;
1910
1911        if (log && rename(git_path("logs/%s", oldrefname), git_path(TMP_RENAMED_LOG)))
1912                return error("unable to move logfile logs/%s to "TMP_RENAMED_LOG": %s",
1913                        oldrefname, strerror(errno));
1914
1915        if (delete_ref(oldrefname, orig_sha1, REF_NODEREF)) {
1916                error("unable to delete old %s", oldrefname);
1917                goto rollback;
1918        }
1919
1920        if (!read_ref_full(newrefname, sha1, 1, &flag) &&
1921            delete_ref(newrefname, sha1, REF_NODEREF)) {
1922                if (errno==EISDIR) {
1923                        if (remove_empty_directories(git_path("%s", newrefname))) {
1924                                error("Directory not empty: %s", newrefname);
1925                                goto rollback;
1926                        }
1927                } else {
1928                        error("unable to delete existing %s", newrefname);
1929                        goto rollback;
1930                }
1931        }
1932
1933        if (log && safe_create_leading_directories(git_path("logs/%s", newrefname))) {
1934                error("unable to create directory for %s", newrefname);
1935                goto rollback;
1936        }
1937
1938 retry:
1939        if (log && rename(git_path(TMP_RENAMED_LOG), git_path("logs/%s", newrefname))) {
1940                if (errno==EISDIR || errno==ENOTDIR) {
1941                        /*
1942                         * rename(a, b) when b is an existing
1943                         * directory ought to result in ISDIR, but
1944                         * Solaris 5.8 gives ENOTDIR.  Sheesh.
1945                         */
1946                        if (remove_empty_directories(git_path("logs/%s", newrefname))) {
1947                                error("Directory not empty: logs/%s", newrefname);
1948                                goto rollback;
1949                        }
1950                        goto retry;
1951                } else {
1952                        error("unable to move logfile "TMP_RENAMED_LOG" to logs/%s: %s",
1953                                newrefname, strerror(errno));
1954                        goto rollback;
1955                }
1956        }
1957        logmoved = log;
1958
1959        lock = lock_ref_sha1_basic(newrefname, NULL, 0, NULL);
1960        if (!lock) {
1961                error("unable to lock %s for update", newrefname);
1962                goto rollback;
1963        }
1964        lock->force_write = 1;
1965        hashcpy(lock->old_sha1, orig_sha1);
1966        if (write_ref_sha1(lock, orig_sha1, logmsg)) {
1967                error("unable to write current sha1 into %s", newrefname);
1968                goto rollback;
1969        }
1970
1971        return 0;
1972
1973 rollback:
1974        lock = lock_ref_sha1_basic(oldrefname, NULL, 0, NULL);
1975        if (!lock) {
1976                error("unable to lock %s for rollback", oldrefname);
1977                goto rollbacklog;
1978        }
1979
1980        lock->force_write = 1;
1981        flag = log_all_ref_updates;
1982        log_all_ref_updates = 0;
1983        if (write_ref_sha1(lock, orig_sha1, NULL))
1984                error("unable to write current sha1 into %s", oldrefname);
1985        log_all_ref_updates = flag;
1986
1987 rollbacklog:
1988        if (logmoved && rename(git_path("logs/%s", newrefname), git_path("logs/%s", oldrefname)))
1989                error("unable to restore logfile %s from %s: %s",
1990                        oldrefname, newrefname, strerror(errno));
1991        if (!logmoved && log &&
1992            rename(git_path(TMP_RENAMED_LOG), git_path("logs/%s", oldrefname)))
1993                error("unable to restore logfile %s from "TMP_RENAMED_LOG": %s",
1994                        oldrefname, strerror(errno));
1995
1996        return 1;
1997}
1998
1999int close_ref(struct ref_lock *lock)
2000{
2001        if (close_lock_file(lock->lk))
2002                return -1;
2003        lock->lock_fd = -1;
2004        return 0;
2005}
2006
2007int commit_ref(struct ref_lock *lock)
2008{
2009        if (commit_lock_file(lock->lk))
2010                return -1;
2011        lock->lock_fd = -1;
2012        return 0;
2013}
2014
2015void unlock_ref(struct ref_lock *lock)
2016{
2017        /* Do not free lock->lk -- atexit() still looks at them */
2018        if (lock->lk)
2019                rollback_lock_file(lock->lk);
2020        free(lock->ref_name);
2021        free(lock->orig_ref_name);
2022        free(lock);
2023}
2024
2025/*
2026 * copy the reflog message msg to buf, which has been allocated sufficiently
2027 * large, while cleaning up the whitespaces.  Especially, convert LF to space,
2028 * because reflog file is one line per entry.
2029 */
2030static int copy_msg(char *buf, const char *msg)
2031{
2032        char *cp = buf;
2033        char c;
2034        int wasspace = 1;
2035
2036        *cp++ = '\t';
2037        while ((c = *msg++)) {
2038                if (wasspace && isspace(c))
2039                        continue;
2040                wasspace = isspace(c);
2041                if (wasspace)
2042                        c = ' ';
2043                *cp++ = c;
2044        }
2045        while (buf < cp && isspace(cp[-1]))
2046                cp--;
2047        *cp++ = '\n';
2048        return cp - buf;
2049}
2050
2051int log_ref_setup(const char *refname, char *logfile, int bufsize)
2052{
2053        int logfd, oflags = O_APPEND | O_WRONLY;
2054
2055        git_snpath(logfile, bufsize, "logs/%s", refname);
2056        if (log_all_ref_updates &&
2057            (!prefixcmp(refname, "refs/heads/") ||
2058             !prefixcmp(refname, "refs/remotes/") ||
2059             !prefixcmp(refname, "refs/notes/") ||
2060             !strcmp(refname, "HEAD"))) {
2061                if (safe_create_leading_directories(logfile) < 0)
2062                        return error("unable to create directory for %s",
2063                                     logfile);
2064                oflags |= O_CREAT;
2065        }
2066
2067        logfd = open(logfile, oflags, 0666);
2068        if (logfd < 0) {
2069                if (!(oflags & O_CREAT) && errno == ENOENT)
2070                        return 0;
2071
2072                if ((oflags & O_CREAT) && errno == EISDIR) {
2073                        if (remove_empty_directories(logfile)) {
2074                                return error("There are still logs under '%s'",
2075                                             logfile);
2076                        }
2077                        logfd = open(logfile, oflags, 0666);
2078                }
2079
2080                if (logfd < 0)
2081                        return error("Unable to append to %s: %s",
2082                                     logfile, strerror(errno));
2083        }
2084
2085        adjust_shared_perm(logfile);
2086        close(logfd);
2087        return 0;
2088}
2089
2090static int log_ref_write(const char *refname, const unsigned char *old_sha1,
2091                         const unsigned char *new_sha1, const char *msg)
2092{
2093        int logfd, result, written, oflags = O_APPEND | O_WRONLY;
2094        unsigned maxlen, len;
2095        int msglen;
2096        char log_file[PATH_MAX];
2097        char *logrec;
2098        const char *committer;
2099
2100        if (log_all_ref_updates < 0)
2101                log_all_ref_updates = !is_bare_repository();
2102
2103        result = log_ref_setup(refname, log_file, sizeof(log_file));
2104        if (result)
2105                return result;
2106
2107        logfd = open(log_file, oflags);
2108        if (logfd < 0)
2109                return 0;
2110        msglen = msg ? strlen(msg) : 0;
2111        committer = git_committer_info(0);
2112        maxlen = strlen(committer) + msglen + 100;
2113        logrec = xmalloc(maxlen);
2114        len = sprintf(logrec, "%s %s %s\n",
2115                      sha1_to_hex(old_sha1),
2116                      sha1_to_hex(new_sha1),
2117                      committer);
2118        if (msglen)
2119                len += copy_msg(logrec + len - 1, msg) - 1;
2120        written = len <= maxlen ? write_in_full(logfd, logrec, len) : -1;
2121        free(logrec);
2122        if (close(logfd) != 0 || written != len)
2123                return error("Unable to append to %s", log_file);
2124        return 0;
2125}
2126
2127static int is_branch(const char *refname)
2128{
2129        return !strcmp(refname, "HEAD") || !prefixcmp(refname, "refs/heads/");
2130}
2131
2132int write_ref_sha1(struct ref_lock *lock,
2133        const unsigned char *sha1, const char *logmsg)
2134{
2135        static char term = '\n';
2136        struct object *o;
2137
2138        if (!lock)
2139                return -1;
2140        if (!lock->force_write && !hashcmp(lock->old_sha1, sha1)) {
2141                unlock_ref(lock);
2142                return 0;
2143        }
2144        o = parse_object(sha1);
2145        if (!o) {
2146                error("Trying to write ref %s with nonexistent object %s",
2147                        lock->ref_name, sha1_to_hex(sha1));
2148                unlock_ref(lock);
2149                return -1;
2150        }
2151        if (o->type != OBJ_COMMIT && is_branch(lock->ref_name)) {
2152                error("Trying to write non-commit object %s to branch %s",
2153                        sha1_to_hex(sha1), lock->ref_name);
2154                unlock_ref(lock);
2155                return -1;
2156        }
2157        if (write_in_full(lock->lock_fd, sha1_to_hex(sha1), 40) != 40 ||
2158            write_in_full(lock->lock_fd, &term, 1) != 1
2159                || close_ref(lock) < 0) {
2160                error("Couldn't write %s", lock->lk->filename);
2161                unlock_ref(lock);
2162                return -1;
2163        }
2164        clear_loose_ref_cache(get_ref_cache(NULL));
2165        if (log_ref_write(lock->ref_name, lock->old_sha1, sha1, logmsg) < 0 ||
2166            (strcmp(lock->ref_name, lock->orig_ref_name) &&
2167             log_ref_write(lock->orig_ref_name, lock->old_sha1, sha1, logmsg) < 0)) {
2168                unlock_ref(lock);
2169                return -1;
2170        }
2171        if (strcmp(lock->orig_ref_name, "HEAD") != 0) {
2172                /*
2173                 * Special hack: If a branch is updated directly and HEAD
2174                 * points to it (may happen on the remote side of a push
2175                 * for example) then logically the HEAD reflog should be
2176                 * updated too.
2177                 * A generic solution implies reverse symref information,
2178                 * but finding all symrefs pointing to the given branch
2179                 * would be rather costly for this rare event (the direct
2180                 * update of a branch) to be worth it.  So let's cheat and
2181                 * check with HEAD only which should cover 99% of all usage
2182                 * scenarios (even 100% of the default ones).
2183                 */
2184                unsigned char head_sha1[20];
2185                int head_flag;
2186                const char *head_ref;
2187                head_ref = resolve_ref_unsafe("HEAD", head_sha1, 1, &head_flag);
2188                if (head_ref && (head_flag & REF_ISSYMREF) &&
2189                    !strcmp(head_ref, lock->ref_name))
2190                        log_ref_write("HEAD", lock->old_sha1, sha1, logmsg);
2191        }
2192        if (commit_ref(lock)) {
2193                error("Couldn't set %s", lock->ref_name);
2194                unlock_ref(lock);
2195                return -1;
2196        }
2197        unlock_ref(lock);
2198        return 0;
2199}
2200
2201int create_symref(const char *ref_target, const char *refs_heads_master,
2202                  const char *logmsg)
2203{
2204        const char *lockpath;
2205        char ref[1000];
2206        int fd, len, written;
2207        char *git_HEAD = git_pathdup("%s", ref_target);
2208        unsigned char old_sha1[20], new_sha1[20];
2209
2210        if (logmsg && read_ref(ref_target, old_sha1))
2211                hashclr(old_sha1);
2212
2213        if (safe_create_leading_directories(git_HEAD) < 0)
2214                return error("unable to create directory for %s", git_HEAD);
2215
2216#ifndef NO_SYMLINK_HEAD
2217        if (prefer_symlink_refs) {
2218                unlink(git_HEAD);
2219                if (!symlink(refs_heads_master, git_HEAD))
2220                        goto done;
2221                fprintf(stderr, "no symlink - falling back to symbolic ref\n");
2222        }
2223#endif
2224
2225        len = snprintf(ref, sizeof(ref), "ref: %s\n", refs_heads_master);
2226        if (sizeof(ref) <= len) {
2227                error("refname too long: %s", refs_heads_master);
2228                goto error_free_return;
2229        }
2230        lockpath = mkpath("%s.lock", git_HEAD);
2231        fd = open(lockpath, O_CREAT | O_EXCL | O_WRONLY, 0666);
2232        if (fd < 0) {
2233                error("Unable to open %s for writing", lockpath);
2234                goto error_free_return;
2235        }
2236        written = write_in_full(fd, ref, len);
2237        if (close(fd) != 0 || written != len) {
2238                error("Unable to write to %s", lockpath);
2239                goto error_unlink_return;
2240        }
2241        if (rename(lockpath, git_HEAD) < 0) {
2242                error("Unable to create %s", git_HEAD);
2243                goto error_unlink_return;
2244        }
2245        if (adjust_shared_perm(git_HEAD)) {
2246                error("Unable to fix permissions on %s", lockpath);
2247        error_unlink_return:
2248                unlink_or_warn(lockpath);
2249        error_free_return:
2250                free(git_HEAD);
2251                return -1;
2252        }
2253
2254#ifndef NO_SYMLINK_HEAD
2255        done:
2256#endif
2257        if (logmsg && !read_ref(refs_heads_master, new_sha1))
2258                log_ref_write(ref_target, old_sha1, new_sha1, logmsg);
2259
2260        free(git_HEAD);
2261        return 0;
2262}
2263
2264static char *ref_msg(const char *line, const char *endp)
2265{
2266        const char *ep;
2267        line += 82;
2268        ep = memchr(line, '\n', endp - line);
2269        if (!ep)
2270                ep = endp;
2271        return xmemdupz(line, ep - line);
2272}
2273
2274int read_ref_at(const char *refname, unsigned long at_time, int cnt,
2275                unsigned char *sha1, char **msg,
2276                unsigned long *cutoff_time, int *cutoff_tz, int *cutoff_cnt)
2277{
2278        const char *logfile, *logdata, *logend, *rec, *lastgt, *lastrec;
2279        char *tz_c;
2280        int logfd, tz, reccnt = 0;
2281        struct stat st;
2282        unsigned long date;
2283        unsigned char logged_sha1[20];
2284        void *log_mapped;
2285        size_t mapsz;
2286
2287        logfile = git_path("logs/%s", refname);
2288        logfd = open(logfile, O_RDONLY, 0);
2289        if (logfd < 0)
2290                die_errno("Unable to read log '%s'", logfile);
2291        fstat(logfd, &st);
2292        if (!st.st_size)
2293                die("Log %s is empty.", logfile);
2294        mapsz = xsize_t(st.st_size);
2295        log_mapped = xmmap(NULL, mapsz, PROT_READ, MAP_PRIVATE, logfd, 0);
2296        logdata = log_mapped;
2297        close(logfd);
2298
2299        lastrec = NULL;
2300        rec = logend = logdata + st.st_size;
2301        while (logdata < rec) {
2302                reccnt++;
2303                if (logdata < rec && *(rec-1) == '\n')
2304                        rec--;
2305                lastgt = NULL;
2306                while (logdata < rec && *(rec-1) != '\n') {
2307                        rec--;
2308                        if (*rec == '>')
2309                                lastgt = rec;
2310                }
2311                if (!lastgt)
2312                        die("Log %s is corrupt.", logfile);
2313                date = strtoul(lastgt + 1, &tz_c, 10);
2314                if (date <= at_time || cnt == 0) {
2315                        tz = strtoul(tz_c, NULL, 10);
2316                        if (msg)
2317                                *msg = ref_msg(rec, logend);
2318                        if (cutoff_time)
2319                                *cutoff_time = date;
2320                        if (cutoff_tz)
2321                                *cutoff_tz = tz;
2322                        if (cutoff_cnt)
2323                                *cutoff_cnt = reccnt - 1;
2324                        if (lastrec) {
2325                                if (get_sha1_hex(lastrec, logged_sha1))
2326                                        die("Log %s is corrupt.", logfile);
2327                                if (get_sha1_hex(rec + 41, sha1))
2328                                        die("Log %s is corrupt.", logfile);
2329                                if (hashcmp(logged_sha1, sha1)) {
2330                                        warning("Log %s has gap after %s.",
2331                                                logfile, show_date(date, tz, DATE_RFC2822));
2332                                }
2333                        }
2334                        else if (date == at_time) {
2335                                if (get_sha1_hex(rec + 41, sha1))
2336                                        die("Log %s is corrupt.", logfile);
2337                        }
2338                        else {
2339                                if (get_sha1_hex(rec + 41, logged_sha1))
2340                                        die("Log %s is corrupt.", logfile);
2341                                if (hashcmp(logged_sha1, sha1)) {
2342                                        warning("Log %s unexpectedly ended on %s.",
2343                                                logfile, show_date(date, tz, DATE_RFC2822));
2344                                }
2345                        }
2346                        munmap(log_mapped, mapsz);
2347                        return 0;
2348                }
2349                lastrec = rec;
2350                if (cnt > 0)
2351                        cnt--;
2352        }
2353
2354        rec = logdata;
2355        while (rec < logend && *rec != '>' && *rec != '\n')
2356                rec++;
2357        if (rec == logend || *rec == '\n')
2358                die("Log %s is corrupt.", logfile);
2359        date = strtoul(rec + 1, &tz_c, 10);
2360        tz = strtoul(tz_c, NULL, 10);
2361        if (get_sha1_hex(logdata, sha1))
2362                die("Log %s is corrupt.", logfile);
2363        if (is_null_sha1(sha1)) {
2364                if (get_sha1_hex(logdata + 41, sha1))
2365                        die("Log %s is corrupt.", logfile);
2366        }
2367        if (msg)
2368                *msg = ref_msg(logdata, logend);
2369        munmap(log_mapped, mapsz);
2370
2371        if (cutoff_time)
2372                *cutoff_time = date;
2373        if (cutoff_tz)
2374                *cutoff_tz = tz;
2375        if (cutoff_cnt)
2376                *cutoff_cnt = reccnt;
2377        return 1;
2378}
2379
2380int for_each_recent_reflog_ent(const char *refname, each_reflog_ent_fn fn, long ofs, void *cb_data)
2381{
2382        const char *logfile;
2383        FILE *logfp;
2384        struct strbuf sb = STRBUF_INIT;
2385        int ret = 0;
2386
2387        logfile = git_path("logs/%s", refname);
2388        logfp = fopen(logfile, "r");
2389        if (!logfp)
2390                return -1;
2391
2392        if (ofs) {
2393                struct stat statbuf;
2394                if (fstat(fileno(logfp), &statbuf) ||
2395                    statbuf.st_size < ofs ||
2396                    fseek(logfp, -ofs, SEEK_END) ||
2397                    strbuf_getwholeline(&sb, logfp, '\n')) {
2398                        fclose(logfp);
2399                        strbuf_release(&sb);
2400                        return -1;
2401                }
2402        }
2403
2404        while (!strbuf_getwholeline(&sb, logfp, '\n')) {
2405                unsigned char osha1[20], nsha1[20];
2406                char *email_end, *message;
2407                unsigned long timestamp;
2408                int tz;
2409
2410                /* old SP new SP name <email> SP time TAB msg LF */
2411                if (sb.len < 83 || sb.buf[sb.len - 1] != '\n' ||
2412                    get_sha1_hex(sb.buf, osha1) || sb.buf[40] != ' ' ||
2413                    get_sha1_hex(sb.buf + 41, nsha1) || sb.buf[81] != ' ' ||
2414                    !(email_end = strchr(sb.buf + 82, '>')) ||
2415                    email_end[1] != ' ' ||
2416                    !(timestamp = strtoul(email_end + 2, &message, 10)) ||
2417                    !message || message[0] != ' ' ||
2418                    (message[1] != '+' && message[1] != '-') ||
2419                    !isdigit(message[2]) || !isdigit(message[3]) ||
2420                    !isdigit(message[4]) || !isdigit(message[5]))
2421                        continue; /* corrupt? */
2422                email_end[1] = '\0';
2423                tz = strtol(message + 1, NULL, 10);
2424                if (message[6] != '\t')
2425                        message += 6;
2426                else
2427                        message += 7;
2428                ret = fn(osha1, nsha1, sb.buf + 82, timestamp, tz, message,
2429                         cb_data);
2430                if (ret)
2431                        break;
2432        }
2433        fclose(logfp);
2434        strbuf_release(&sb);
2435        return ret;
2436}
2437
2438int for_each_reflog_ent(const char *refname, each_reflog_ent_fn fn, void *cb_data)
2439{
2440        return for_each_recent_reflog_ent(refname, fn, 0, cb_data);
2441}
2442
2443/*
2444 * Call fn for each reflog in the namespace indicated by name.  name
2445 * must be empty or end with '/'.  Name will be used as a scratch
2446 * space, but its contents will be restored before return.
2447 */
2448static int do_for_each_reflog(struct strbuf *name, each_ref_fn fn, void *cb_data)
2449{
2450        DIR *d = opendir(git_path("logs/%s", name->buf));
2451        int retval = 0;
2452        struct dirent *de;
2453        int oldlen = name->len;
2454
2455        if (!d)
2456                return name->len ? errno : 0;
2457
2458        while ((de = readdir(d)) != NULL) {
2459                struct stat st;
2460
2461                if (de->d_name[0] == '.')
2462                        continue;
2463                if (has_extension(de->d_name, ".lock"))
2464                        continue;
2465                strbuf_addstr(name, de->d_name);
2466                if (stat(git_path("logs/%s", name->buf), &st) < 0) {
2467                        ; /* silently ignore */
2468                } else {
2469                        if (S_ISDIR(st.st_mode)) {
2470                                strbuf_addch(name, '/');
2471                                retval = do_for_each_reflog(name, fn, cb_data);
2472                        } else {
2473                                unsigned char sha1[20];
2474                                if (read_ref_full(name->buf, sha1, 0, NULL))
2475                                        retval = error("bad ref for %s", name->buf);
2476                                else
2477                                        retval = fn(name->buf, sha1, 0, cb_data);
2478                        }
2479                        if (retval)
2480                                break;
2481                }
2482                strbuf_setlen(name, oldlen);
2483        }
2484        closedir(d);
2485        return retval;
2486}
2487
2488int for_each_reflog(each_ref_fn fn, void *cb_data)
2489{
2490        int retval;
2491        struct strbuf name;
2492        strbuf_init(&name, PATH_MAX);
2493        retval = do_for_each_reflog(&name, fn, cb_data);
2494        strbuf_release(&name);
2495        return retval;
2496}
2497
2498int update_ref(const char *action, const char *refname,
2499                const unsigned char *sha1, const unsigned char *oldval,
2500                int flags, enum action_on_err onerr)
2501{
2502        static struct ref_lock *lock;
2503        lock = lock_any_ref_for_update(refname, oldval, flags);
2504        if (!lock) {
2505                const char *str = "Cannot lock 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        if (write_ref_sha1(lock, sha1, action) < 0) {
2514                const char *str = "Cannot update the ref '%s'.";
2515                switch (onerr) {
2516                case MSG_ON_ERR: error(str, refname); break;
2517                case DIE_ON_ERR: die(str, refname); break;
2518                case QUIET_ON_ERR: break;
2519                }
2520                return 1;
2521        }
2522        return 0;
2523}
2524
2525struct ref *find_ref_by_name(const struct ref *list, const char *name)
2526{
2527        for ( ; list; list = list->next)
2528                if (!strcmp(list->name, name))
2529                        return (struct ref *)list;
2530        return NULL;
2531}
2532
2533/*
2534 * generate a format suitable for scanf from a ref_rev_parse_rules
2535 * rule, that is replace the "%.*s" spec with a "%s" spec
2536 */
2537static void gen_scanf_fmt(char *scanf_fmt, const char *rule)
2538{
2539        char *spec;
2540
2541        spec = strstr(rule, "%.*s");
2542        if (!spec || strstr(spec + 4, "%.*s"))
2543                die("invalid rule in ref_rev_parse_rules: %s", rule);
2544
2545        /* copy all until spec */
2546        strncpy(scanf_fmt, rule, spec - rule);
2547        scanf_fmt[spec - rule] = '\0';
2548        /* copy new spec */
2549        strcat(scanf_fmt, "%s");
2550        /* copy remaining rule */
2551        strcat(scanf_fmt, spec + 4);
2552
2553        return;
2554}
2555
2556char *shorten_unambiguous_ref(const char *refname, int strict)
2557{
2558        int i;
2559        static char **scanf_fmts;
2560        static int nr_rules;
2561        char *short_name;
2562
2563        /* pre generate scanf formats from ref_rev_parse_rules[] */
2564        if (!nr_rules) {
2565                size_t total_len = 0;
2566
2567                /* the rule list is NULL terminated, count them first */
2568                for (; ref_rev_parse_rules[nr_rules]; nr_rules++)
2569                        /* no +1 because strlen("%s") < strlen("%.*s") */
2570                        total_len += strlen(ref_rev_parse_rules[nr_rules]);
2571
2572                scanf_fmts = xmalloc(nr_rules * sizeof(char *) + total_len);
2573
2574                total_len = 0;
2575                for (i = 0; i < nr_rules; i++) {
2576                        scanf_fmts[i] = (char *)&scanf_fmts[nr_rules]
2577                                        + total_len;
2578                        gen_scanf_fmt(scanf_fmts[i], ref_rev_parse_rules[i]);
2579                        total_len += strlen(ref_rev_parse_rules[i]);
2580                }
2581        }
2582
2583        /* bail out if there are no rules */
2584        if (!nr_rules)
2585                return xstrdup(refname);
2586
2587        /* buffer for scanf result, at most refname must fit */
2588        short_name = xstrdup(refname);
2589
2590        /* skip first rule, it will always match */
2591        for (i = nr_rules - 1; i > 0 ; --i) {
2592                int j;
2593                int rules_to_fail = i;
2594                int short_name_len;
2595
2596                if (1 != sscanf(refname, scanf_fmts[i], short_name))
2597                        continue;
2598
2599                short_name_len = strlen(short_name);
2600
2601                /*
2602                 * in strict mode, all (except the matched one) rules
2603                 * must fail to resolve to a valid non-ambiguous ref
2604                 */
2605                if (strict)
2606                        rules_to_fail = nr_rules;
2607
2608                /*
2609                 * check if the short name resolves to a valid ref,
2610                 * but use only rules prior to the matched one
2611                 */
2612                for (j = 0; j < rules_to_fail; j++) {
2613                        const char *rule = ref_rev_parse_rules[j];
2614                        char refname[PATH_MAX];
2615
2616                        /* skip matched rule */
2617                        if (i == j)
2618                                continue;
2619
2620                        /*
2621                         * the short name is ambiguous, if it resolves
2622                         * (with this previous rule) to a valid ref
2623                         * read_ref() returns 0 on success
2624                         */
2625                        mksnpath(refname, sizeof(refname),
2626                                 rule, short_name_len, short_name);
2627                        if (ref_exists(refname))
2628                                break;
2629                }
2630
2631                /*
2632                 * short name is non-ambiguous if all previous rules
2633                 * haven't resolved to a valid ref
2634                 */
2635                if (j == rules_to_fail)
2636                        return short_name;
2637        }
2638
2639        free(short_name);
2640        return xstrdup(refname);
2641}