Merge branch 'mh/ref-races-optim-invalidate-cached'
[git/git.git] / refs.c
1 #include "cache.h"
2 #include "refs.h"
3 #include "object.h"
4 #include "tag.h"
5 #include "dir.h"
6 #include "string-list.h"
7
8 /*
9 * Make sure "ref" is something reasonable to have under ".git/refs/";
10 * We do not like it if:
11 *
12 * - any path component of it begins with ".", or
13 * - it has double dots "..", or
14 * - it has ASCII control character, "~", "^", ":" or SP, anywhere, or
15 * - it ends with a "/".
16 * - it ends with ".lock"
17 * - it contains a "\" (backslash)
18 */
19
20 /* Return true iff ch is not allowed in reference names. */
21 static inline int bad_ref_char(int ch)
22 {
23 if (((unsigned) ch) <= ' ' || ch == 0x7f ||
24 ch == '~' || ch == '^' || ch == ':' || ch == '\\')
25 return 1;
26 /* 2.13 Pattern Matching Notation */
27 if (ch == '*' || ch == '?' || ch == '[') /* Unsupported */
28 return 1;
29 return 0;
30 }
31
32 /*
33 * Try to read one refname component from the front of refname. Return
34 * the length of the component found, or -1 if the component is not
35 * legal.
36 */
37 static int check_refname_component(const char *refname, int flags)
38 {
39 const char *cp;
40 char last = '\0';
41
42 for (cp = refname; ; cp++) {
43 char ch = *cp;
44 if (ch == '\0' || ch == '/')
45 break;
46 if (bad_ref_char(ch))
47 return -1; /* Illegal character in refname. */
48 if (last == '.' && ch == '.')
49 return -1; /* Refname contains "..". */
50 if (last == '@' && ch == '{')
51 return -1; /* Refname contains "@{". */
52 last = ch;
53 }
54 if (cp == refname)
55 return 0; /* Component has zero length. */
56 if (refname[0] == '.') {
57 if (!(flags & REFNAME_DOT_COMPONENT))
58 return -1; /* Component starts with '.'. */
59 /*
60 * Even if leading dots are allowed, don't allow "."
61 * as a component (".." is prevented by a rule above).
62 */
63 if (refname[1] == '\0')
64 return -1; /* Component equals ".". */
65 }
66 if (cp - refname >= 5 && !memcmp(cp - 5, ".lock", 5))
67 return -1; /* Refname ends with ".lock". */
68 return cp - refname;
69 }
70
71 int check_refname_format(const char *refname, int flags)
72 {
73 int component_len, component_count = 0;
74
75 if (!strcmp(refname, "@"))
76 /* Refname is a single character '@'. */
77 return -1;
78
79 while (1) {
80 /* We are at the start of a path component. */
81 component_len = check_refname_component(refname, flags);
82 if (component_len <= 0) {
83 if ((flags & REFNAME_REFSPEC_PATTERN) &&
84 refname[0] == '*' &&
85 (refname[1] == '\0' || refname[1] == '/')) {
86 /* Accept one wildcard as a full refname component. */
87 flags &= ~REFNAME_REFSPEC_PATTERN;
88 component_len = 1;
89 } else {
90 return -1;
91 }
92 }
93 component_count++;
94 if (refname[component_len] == '\0')
95 break;
96 /* Skip to next component. */
97 refname += component_len + 1;
98 }
99
100 if (refname[component_len - 1] == '.')
101 return -1; /* Refname ends with '.'. */
102 if (!(flags & REFNAME_ALLOW_ONELEVEL) && component_count < 2)
103 return -1; /* Refname has only one component. */
104 return 0;
105 }
106
107 struct ref_entry;
108
109 /*
110 * Information used (along with the information in ref_entry) to
111 * describe a single cached reference. This data structure only
112 * occurs embedded in a union in struct ref_entry, and only when
113 * (ref_entry->flag & REF_DIR) is zero.
114 */
115 struct ref_value {
116 /*
117 * The name of the object to which this reference resolves
118 * (which may be a tag object). If REF_ISBROKEN, this is
119 * null. If REF_ISSYMREF, then this is the name of the object
120 * referred to by the last reference in the symlink chain.
121 */
122 unsigned char sha1[20];
123
124 /*
125 * If REF_KNOWS_PEELED, then this field holds the peeled value
126 * of this reference, or null if the reference is known not to
127 * be peelable. See the documentation for peel_ref() for an
128 * exact definition of "peelable".
129 */
130 unsigned char peeled[20];
131 };
132
133 struct ref_cache;
134
135 /*
136 * Information used (along with the information in ref_entry) to
137 * describe a level in the hierarchy of references. This data
138 * structure only occurs embedded in a union in struct ref_entry, and
139 * only when (ref_entry.flag & REF_DIR) is set. In that case,
140 * (ref_entry.flag & REF_INCOMPLETE) determines whether the references
141 * in the directory have already been read:
142 *
143 * (ref_entry.flag & REF_INCOMPLETE) unset -- a directory of loose
144 * or packed references, already read.
145 *
146 * (ref_entry.flag & REF_INCOMPLETE) set -- a directory of loose
147 * references that hasn't been read yet (nor has any of its
148 * subdirectories).
149 *
150 * Entries within a directory are stored within a growable array of
151 * pointers to ref_entries (entries, nr, alloc). Entries 0 <= i <
152 * sorted are sorted by their component name in strcmp() order and the
153 * remaining entries are unsorted.
154 *
155 * Loose references are read lazily, one directory at a time. When a
156 * directory of loose references is read, then all of the references
157 * in that directory are stored, and REF_INCOMPLETE stubs are created
158 * for any subdirectories, but the subdirectories themselves are not
159 * read. The reading is triggered by get_ref_dir().
160 */
161 struct ref_dir {
162 int nr, alloc;
163
164 /*
165 * Entries with index 0 <= i < sorted are sorted by name. New
166 * entries are appended to the list unsorted, and are sorted
167 * only when required; thus we avoid the need to sort the list
168 * after the addition of every reference.
169 */
170 int sorted;
171
172 /* A pointer to the ref_cache that contains this ref_dir. */
173 struct ref_cache *ref_cache;
174
175 struct ref_entry **entries;
176 };
177
178 /*
179 * Bit values for ref_entry::flag. REF_ISSYMREF=0x01,
180 * REF_ISPACKED=0x02, and REF_ISBROKEN=0x04 are public values; see
181 * refs.h.
182 */
183
184 /*
185 * The field ref_entry->u.value.peeled of this value entry contains
186 * the correct peeled value for the reference, which might be
187 * null_sha1 if the reference is not a tag or if it is broken.
188 */
189 #define REF_KNOWS_PEELED 0x08
190
191 /* ref_entry represents a directory of references */
192 #define REF_DIR 0x10
193
194 /*
195 * Entry has not yet been read from disk (used only for REF_DIR
196 * entries representing loose references)
197 */
198 #define REF_INCOMPLETE 0x20
199
200 /*
201 * A ref_entry represents either a reference or a "subdirectory" of
202 * references.
203 *
204 * Each directory in the reference namespace is represented by a
205 * ref_entry with (flags & REF_DIR) set and containing a subdir member
206 * that holds the entries in that directory that have been read so
207 * far. If (flags & REF_INCOMPLETE) is set, then the directory and
208 * its subdirectories haven't been read yet. REF_INCOMPLETE is only
209 * used for loose reference directories.
210 *
211 * References are represented by a ref_entry with (flags & REF_DIR)
212 * unset and a value member that describes the reference's value. The
213 * flag member is at the ref_entry level, but it is also needed to
214 * interpret the contents of the value field (in other words, a
215 * ref_value object is not very much use without the enclosing
216 * ref_entry).
217 *
218 * Reference names cannot end with slash and directories' names are
219 * always stored with a trailing slash (except for the top-level
220 * directory, which is always denoted by ""). This has two nice
221 * consequences: (1) when the entries in each subdir are sorted
222 * lexicographically by name (as they usually are), the references in
223 * a whole tree can be generated in lexicographic order by traversing
224 * the tree in left-to-right, depth-first order; (2) the names of
225 * references and subdirectories cannot conflict, and therefore the
226 * presence of an empty subdirectory does not block the creation of a
227 * similarly-named reference. (The fact that reference names with the
228 * same leading components can conflict *with each other* is a
229 * separate issue that is regulated by is_refname_available().)
230 *
231 * Please note that the name field contains the fully-qualified
232 * reference (or subdirectory) name. Space could be saved by only
233 * storing the relative names. But that would require the full names
234 * to be generated on the fly when iterating in do_for_each_ref(), and
235 * would break callback functions, who have always been able to assume
236 * that the name strings that they are passed will not be freed during
237 * the iteration.
238 */
239 struct ref_entry {
240 unsigned char flag; /* ISSYMREF? ISPACKED? */
241 union {
242 struct ref_value value; /* if not (flags&REF_DIR) */
243 struct ref_dir subdir; /* if (flags&REF_DIR) */
244 } u;
245 /*
246 * The full name of the reference (e.g., "refs/heads/master")
247 * or the full name of the directory with a trailing slash
248 * (e.g., "refs/heads/"):
249 */
250 char name[FLEX_ARRAY];
251 };
252
253 static void read_loose_refs(const char *dirname, struct ref_dir *dir);
254
255 static struct ref_dir *get_ref_dir(struct ref_entry *entry)
256 {
257 struct ref_dir *dir;
258 assert(entry->flag & REF_DIR);
259 dir = &entry->u.subdir;
260 if (entry->flag & REF_INCOMPLETE) {
261 read_loose_refs(entry->name, dir);
262 entry->flag &= ~REF_INCOMPLETE;
263 }
264 return dir;
265 }
266
267 static struct ref_entry *create_ref_entry(const char *refname,
268 const unsigned char *sha1, int flag,
269 int check_name)
270 {
271 int len;
272 struct ref_entry *ref;
273
274 if (check_name &&
275 check_refname_format(refname, REFNAME_ALLOW_ONELEVEL|REFNAME_DOT_COMPONENT))
276 die("Reference has invalid format: '%s'", refname);
277 len = strlen(refname) + 1;
278 ref = xmalloc(sizeof(struct ref_entry) + len);
279 hashcpy(ref->u.value.sha1, sha1);
280 hashclr(ref->u.value.peeled);
281 memcpy(ref->name, refname, len);
282 ref->flag = flag;
283 return ref;
284 }
285
286 static void clear_ref_dir(struct ref_dir *dir);
287
288 static void free_ref_entry(struct ref_entry *entry)
289 {
290 if (entry->flag & REF_DIR) {
291 /*
292 * Do not use get_ref_dir() here, as that might
293 * trigger the reading of loose refs.
294 */
295 clear_ref_dir(&entry->u.subdir);
296 }
297 free(entry);
298 }
299
300 /*
301 * Add a ref_entry to the end of dir (unsorted). Entry is always
302 * stored directly in dir; no recursion into subdirectories is
303 * done.
304 */
305 static void add_entry_to_dir(struct ref_dir *dir, struct ref_entry *entry)
306 {
307 ALLOC_GROW(dir->entries, dir->nr + 1, dir->alloc);
308 dir->entries[dir->nr++] = entry;
309 /* optimize for the case that entries are added in order */
310 if (dir->nr == 1 ||
311 (dir->nr == dir->sorted + 1 &&
312 strcmp(dir->entries[dir->nr - 2]->name,
313 dir->entries[dir->nr - 1]->name) < 0))
314 dir->sorted = dir->nr;
315 }
316
317 /*
318 * Clear and free all entries in dir, recursively.
319 */
320 static void clear_ref_dir(struct ref_dir *dir)
321 {
322 int i;
323 for (i = 0; i < dir->nr; i++)
324 free_ref_entry(dir->entries[i]);
325 free(dir->entries);
326 dir->sorted = dir->nr = dir->alloc = 0;
327 dir->entries = NULL;
328 }
329
330 /*
331 * Create a struct ref_entry object for the specified dirname.
332 * dirname is the name of the directory with a trailing slash (e.g.,
333 * "refs/heads/") or "" for the top-level directory.
334 */
335 static struct ref_entry *create_dir_entry(struct ref_cache *ref_cache,
336 const char *dirname, size_t len,
337 int incomplete)
338 {
339 struct ref_entry *direntry;
340 direntry = xcalloc(1, sizeof(struct ref_entry) + len + 1);
341 memcpy(direntry->name, dirname, len);
342 direntry->name[len] = '\0';
343 direntry->u.subdir.ref_cache = ref_cache;
344 direntry->flag = REF_DIR | (incomplete ? REF_INCOMPLETE : 0);
345 return direntry;
346 }
347
348 static int ref_entry_cmp(const void *a, const void *b)
349 {
350 struct ref_entry *one = *(struct ref_entry **)a;
351 struct ref_entry *two = *(struct ref_entry **)b;
352 return strcmp(one->name, two->name);
353 }
354
355 static void sort_ref_dir(struct ref_dir *dir);
356
357 struct string_slice {
358 size_t len;
359 const char *str;
360 };
361
362 static int ref_entry_cmp_sslice(const void *key_, const void *ent_)
363 {
364 const struct string_slice *key = key_;
365 const struct ref_entry *ent = *(const struct ref_entry * const *)ent_;
366 int cmp = strncmp(key->str, ent->name, key->len);
367 if (cmp)
368 return cmp;
369 return '\0' - (unsigned char)ent->name[key->len];
370 }
371
372 /*
373 * Return the index of the entry with the given refname from the
374 * ref_dir (non-recursively), sorting dir if necessary. Return -1 if
375 * no such entry is found. dir must already be complete.
376 */
377 static int search_ref_dir(struct ref_dir *dir, const char *refname, size_t len)
378 {
379 struct ref_entry **r;
380 struct string_slice key;
381
382 if (refname == NULL || !dir->nr)
383 return -1;
384
385 sort_ref_dir(dir);
386 key.len = len;
387 key.str = refname;
388 r = bsearch(&key, dir->entries, dir->nr, sizeof(*dir->entries),
389 ref_entry_cmp_sslice);
390
391 if (r == NULL)
392 return -1;
393
394 return r - dir->entries;
395 }
396
397 /*
398 * Search for a directory entry directly within dir (without
399 * recursing). Sort dir if necessary. subdirname must be a directory
400 * name (i.e., end in '/'). If mkdir is set, then create the
401 * directory if it is missing; otherwise, return NULL if the desired
402 * directory cannot be found. dir must already be complete.
403 */
404 static struct ref_dir *search_for_subdir(struct ref_dir *dir,
405 const char *subdirname, size_t len,
406 int mkdir)
407 {
408 int entry_index = search_ref_dir(dir, subdirname, len);
409 struct ref_entry *entry;
410 if (entry_index == -1) {
411 if (!mkdir)
412 return NULL;
413 /*
414 * Since dir is complete, the absence of a subdir
415 * means that the subdir really doesn't exist;
416 * therefore, create an empty record for it but mark
417 * the record complete.
418 */
419 entry = create_dir_entry(dir->ref_cache, subdirname, len, 0);
420 add_entry_to_dir(dir, entry);
421 } else {
422 entry = dir->entries[entry_index];
423 }
424 return get_ref_dir(entry);
425 }
426
427 /*
428 * If refname is a reference name, find the ref_dir within the dir
429 * tree that should hold refname. If refname is a directory name
430 * (i.e., ends in '/'), then return that ref_dir itself. dir must
431 * represent the top-level directory and must already be complete.
432 * Sort ref_dirs and recurse into subdirectories as necessary. If
433 * mkdir is set, then create any missing directories; otherwise,
434 * return NULL if the desired directory cannot be found.
435 */
436 static struct ref_dir *find_containing_dir(struct ref_dir *dir,
437 const char *refname, int mkdir)
438 {
439 const char *slash;
440 for (slash = strchr(refname, '/'); slash; slash = strchr(slash + 1, '/')) {
441 size_t dirnamelen = slash - refname + 1;
442 struct ref_dir *subdir;
443 subdir = search_for_subdir(dir, refname, dirnamelen, mkdir);
444 if (!subdir) {
445 dir = NULL;
446 break;
447 }
448 dir = subdir;
449 }
450
451 return dir;
452 }
453
454 /*
455 * Find the value entry with the given name in dir, sorting ref_dirs
456 * and recursing into subdirectories as necessary. If the name is not
457 * found or it corresponds to a directory entry, return NULL.
458 */
459 static struct ref_entry *find_ref(struct ref_dir *dir, const char *refname)
460 {
461 int entry_index;
462 struct ref_entry *entry;
463 dir = find_containing_dir(dir, refname, 0);
464 if (!dir)
465 return NULL;
466 entry_index = search_ref_dir(dir, refname, strlen(refname));
467 if (entry_index == -1)
468 return NULL;
469 entry = dir->entries[entry_index];
470 return (entry->flag & REF_DIR) ? NULL : entry;
471 }
472
473 /*
474 * Remove the entry with the given name from dir, recursing into
475 * subdirectories as necessary. If refname is the name of a directory
476 * (i.e., ends with '/'), then remove the directory and its contents.
477 * If the removal was successful, return the number of entries
478 * remaining in the directory entry that contained the deleted entry.
479 * If the name was not found, return -1. Please note that this
480 * function only deletes the entry from the cache; it does not delete
481 * it from the filesystem or ensure that other cache entries (which
482 * might be symbolic references to the removed entry) are updated.
483 * Nor does it remove any containing dir entries that might be made
484 * empty by the removal. dir must represent the top-level directory
485 * and must already be complete.
486 */
487 static int remove_entry(struct ref_dir *dir, const char *refname)
488 {
489 int refname_len = strlen(refname);
490 int entry_index;
491 struct ref_entry *entry;
492 int is_dir = refname[refname_len - 1] == '/';
493 if (is_dir) {
494 /*
495 * refname represents a reference directory. Remove
496 * the trailing slash; otherwise we will get the
497 * directory *representing* refname rather than the
498 * one *containing* it.
499 */
500 char *dirname = xmemdupz(refname, refname_len - 1);
501 dir = find_containing_dir(dir, dirname, 0);
502 free(dirname);
503 } else {
504 dir = find_containing_dir(dir, refname, 0);
505 }
506 if (!dir)
507 return -1;
508 entry_index = search_ref_dir(dir, refname, refname_len);
509 if (entry_index == -1)
510 return -1;
511 entry = dir->entries[entry_index];
512
513 memmove(&dir->entries[entry_index],
514 &dir->entries[entry_index + 1],
515 (dir->nr - entry_index - 1) * sizeof(*dir->entries)
516 );
517 dir->nr--;
518 if (dir->sorted > entry_index)
519 dir->sorted--;
520 free_ref_entry(entry);
521 return dir->nr;
522 }
523
524 /*
525 * Add a ref_entry to the ref_dir (unsorted), recursing into
526 * subdirectories as necessary. dir must represent the top-level
527 * directory. Return 0 on success.
528 */
529 static int add_ref(struct ref_dir *dir, struct ref_entry *ref)
530 {
531 dir = find_containing_dir(dir, ref->name, 1);
532 if (!dir)
533 return -1;
534 add_entry_to_dir(dir, ref);
535 return 0;
536 }
537
538 /*
539 * Emit a warning and return true iff ref1 and ref2 have the same name
540 * and the same sha1. Die if they have the same name but different
541 * sha1s.
542 */
543 static int is_dup_ref(const struct ref_entry *ref1, const struct ref_entry *ref2)
544 {
545 if (strcmp(ref1->name, ref2->name))
546 return 0;
547
548 /* Duplicate name; make sure that they don't conflict: */
549
550 if ((ref1->flag & REF_DIR) || (ref2->flag & REF_DIR))
551 /* This is impossible by construction */
552 die("Reference directory conflict: %s", ref1->name);
553
554 if (hashcmp(ref1->u.value.sha1, ref2->u.value.sha1))
555 die("Duplicated ref, and SHA1s don't match: %s", ref1->name);
556
557 warning("Duplicated ref: %s", ref1->name);
558 return 1;
559 }
560
561 /*
562 * Sort the entries in dir non-recursively (if they are not already
563 * sorted) and remove any duplicate entries.
564 */
565 static void sort_ref_dir(struct ref_dir *dir)
566 {
567 int i, j;
568 struct ref_entry *last = NULL;
569
570 /*
571 * This check also prevents passing a zero-length array to qsort(),
572 * which is a problem on some platforms.
573 */
574 if (dir->sorted == dir->nr)
575 return;
576
577 qsort(dir->entries, dir->nr, sizeof(*dir->entries), ref_entry_cmp);
578
579 /* Remove any duplicates: */
580 for (i = 0, j = 0; j < dir->nr; j++) {
581 struct ref_entry *entry = dir->entries[j];
582 if (last && is_dup_ref(last, entry))
583 free_ref_entry(entry);
584 else
585 last = dir->entries[i++] = entry;
586 }
587 dir->sorted = dir->nr = i;
588 }
589
590 /* Include broken references in a do_for_each_ref*() iteration: */
591 #define DO_FOR_EACH_INCLUDE_BROKEN 0x01
592
593 /*
594 * Return true iff the reference described by entry can be resolved to
595 * an object in the database. Emit a warning if the referred-to
596 * object does not exist.
597 */
598 static int ref_resolves_to_object(struct ref_entry *entry)
599 {
600 if (entry->flag & REF_ISBROKEN)
601 return 0;
602 if (!has_sha1_file(entry->u.value.sha1)) {
603 error("%s does not point to a valid object!", entry->name);
604 return 0;
605 }
606 return 1;
607 }
608
609 /*
610 * current_ref is a performance hack: when iterating over references
611 * using the for_each_ref*() functions, current_ref is set to the
612 * current reference's entry before calling the callback function. If
613 * the callback function calls peel_ref(), then peel_ref() first
614 * checks whether the reference to be peeled is the current reference
615 * (it usually is) and if so, returns that reference's peeled version
616 * if it is available. This avoids a refname lookup in a common case.
617 */
618 static struct ref_entry *current_ref;
619
620 typedef int each_ref_entry_fn(struct ref_entry *entry, void *cb_data);
621
622 struct ref_entry_cb {
623 const char *base;
624 int trim;
625 int flags;
626 each_ref_fn *fn;
627 void *cb_data;
628 };
629
630 /*
631 * Handle one reference in a do_for_each_ref*()-style iteration,
632 * calling an each_ref_fn for each entry.
633 */
634 static int do_one_ref(struct ref_entry *entry, void *cb_data)
635 {
636 struct ref_entry_cb *data = cb_data;
637 int retval;
638 if (prefixcmp(entry->name, data->base))
639 return 0;
640
641 if (!(data->flags & DO_FOR_EACH_INCLUDE_BROKEN) &&
642 !ref_resolves_to_object(entry))
643 return 0;
644
645 current_ref = entry;
646 retval = data->fn(entry->name + data->trim, entry->u.value.sha1,
647 entry->flag, data->cb_data);
648 current_ref = NULL;
649 return retval;
650 }
651
652 /*
653 * Call fn for each reference in dir that has index in the range
654 * offset <= index < dir->nr. Recurse into subdirectories that are in
655 * that index range, sorting them before iterating. This function
656 * does not sort dir itself; it should be sorted beforehand. fn is
657 * called for all references, including broken ones.
658 */
659 static int do_for_each_entry_in_dir(struct ref_dir *dir, int offset,
660 each_ref_entry_fn fn, void *cb_data)
661 {
662 int i;
663 assert(dir->sorted == dir->nr);
664 for (i = offset; i < dir->nr; i++) {
665 struct ref_entry *entry = dir->entries[i];
666 int retval;
667 if (entry->flag & REF_DIR) {
668 struct ref_dir *subdir = get_ref_dir(entry);
669 sort_ref_dir(subdir);
670 retval = do_for_each_entry_in_dir(subdir, 0, fn, cb_data);
671 } else {
672 retval = fn(entry, cb_data);
673 }
674 if (retval)
675 return retval;
676 }
677 return 0;
678 }
679
680 /*
681 * Call fn for each reference in the union of dir1 and dir2, in order
682 * by refname. Recurse into subdirectories. If a value entry appears
683 * in both dir1 and dir2, then only process the version that is in
684 * dir2. The input dirs must already be sorted, but subdirs will be
685 * sorted as needed. fn is called for all references, including
686 * broken ones.
687 */
688 static int do_for_each_entry_in_dirs(struct ref_dir *dir1,
689 struct ref_dir *dir2,
690 each_ref_entry_fn fn, void *cb_data)
691 {
692 int retval;
693 int i1 = 0, i2 = 0;
694
695 assert(dir1->sorted == dir1->nr);
696 assert(dir2->sorted == dir2->nr);
697 while (1) {
698 struct ref_entry *e1, *e2;
699 int cmp;
700 if (i1 == dir1->nr) {
701 return do_for_each_entry_in_dir(dir2, i2, fn, cb_data);
702 }
703 if (i2 == dir2->nr) {
704 return do_for_each_entry_in_dir(dir1, i1, fn, cb_data);
705 }
706 e1 = dir1->entries[i1];
707 e2 = dir2->entries[i2];
708 cmp = strcmp(e1->name, e2->name);
709 if (cmp == 0) {
710 if ((e1->flag & REF_DIR) && (e2->flag & REF_DIR)) {
711 /* Both are directories; descend them in parallel. */
712 struct ref_dir *subdir1 = get_ref_dir(e1);
713 struct ref_dir *subdir2 = get_ref_dir(e2);
714 sort_ref_dir(subdir1);
715 sort_ref_dir(subdir2);
716 retval = do_for_each_entry_in_dirs(
717 subdir1, subdir2, fn, cb_data);
718 i1++;
719 i2++;
720 } else if (!(e1->flag & REF_DIR) && !(e2->flag & REF_DIR)) {
721 /* Both are references; ignore the one from dir1. */
722 retval = fn(e2, cb_data);
723 i1++;
724 i2++;
725 } else {
726 die("conflict between reference and directory: %s",
727 e1->name);
728 }
729 } else {
730 struct ref_entry *e;
731 if (cmp < 0) {
732 e = e1;
733 i1++;
734 } else {
735 e = e2;
736 i2++;
737 }
738 if (e->flag & REF_DIR) {
739 struct ref_dir *subdir = get_ref_dir(e);
740 sort_ref_dir(subdir);
741 retval = do_for_each_entry_in_dir(
742 subdir, 0, fn, cb_data);
743 } else {
744 retval = fn(e, cb_data);
745 }
746 }
747 if (retval)
748 return retval;
749 }
750 }
751
752 /*
753 * Load all of the refs from the dir into our in-memory cache. The hard work
754 * of loading loose refs is done by get_ref_dir(), so we just need to recurse
755 * through all of the sub-directories. We do not even need to care about
756 * sorting, as traversal order does not matter to us.
757 */
758 static void prime_ref_dir(struct ref_dir *dir)
759 {
760 int i;
761 for (i = 0; i < dir->nr; i++) {
762 struct ref_entry *entry = dir->entries[i];
763 if (entry->flag & REF_DIR)
764 prime_ref_dir(get_ref_dir(entry));
765 }
766 }
767 /*
768 * Return true iff refname1 and refname2 conflict with each other.
769 * Two reference names conflict if one of them exactly matches the
770 * leading components of the other; e.g., "foo/bar" conflicts with
771 * both "foo" and with "foo/bar/baz" but not with "foo/bar" or
772 * "foo/barbados".
773 */
774 static int names_conflict(const char *refname1, const char *refname2)
775 {
776 for (; *refname1 && *refname1 == *refname2; refname1++, refname2++)
777 ;
778 return (*refname1 == '\0' && *refname2 == '/')
779 || (*refname1 == '/' && *refname2 == '\0');
780 }
781
782 struct name_conflict_cb {
783 const char *refname;
784 const char *oldrefname;
785 const char *conflicting_refname;
786 };
787
788 static int name_conflict_fn(struct ref_entry *entry, void *cb_data)
789 {
790 struct name_conflict_cb *data = (struct name_conflict_cb *)cb_data;
791 if (data->oldrefname && !strcmp(data->oldrefname, entry->name))
792 return 0;
793 if (names_conflict(data->refname, entry->name)) {
794 data->conflicting_refname = entry->name;
795 return 1;
796 }
797 return 0;
798 }
799
800 /*
801 * Return true iff a reference named refname could be created without
802 * conflicting with the name of an existing reference in dir. If
803 * oldrefname is non-NULL, ignore potential conflicts with oldrefname
804 * (e.g., because oldrefname is scheduled for deletion in the same
805 * operation).
806 */
807 static int is_refname_available(const char *refname, const char *oldrefname,
808 struct ref_dir *dir)
809 {
810 struct name_conflict_cb data;
811 data.refname = refname;
812 data.oldrefname = oldrefname;
813 data.conflicting_refname = NULL;
814
815 sort_ref_dir(dir);
816 if (do_for_each_entry_in_dir(dir, 0, name_conflict_fn, &data)) {
817 error("'%s' exists; cannot create '%s'",
818 data.conflicting_refname, refname);
819 return 0;
820 }
821 return 1;
822 }
823
824 struct packed_ref_cache {
825 struct ref_entry *root;
826
827 /*
828 * Count of references to the data structure in this instance,
829 * including the pointer from ref_cache::packed if any. The
830 * data will not be freed as long as the reference count is
831 * nonzero.
832 */
833 unsigned int referrers;
834
835 /*
836 * Iff the packed-refs file associated with this instance is
837 * currently locked for writing, this points at the associated
838 * lock (which is owned by somebody else). The referrer count
839 * is also incremented when the file is locked and decremented
840 * when it is unlocked.
841 */
842 struct lock_file *lock;
843
844 /* The metadata from when this packed-refs cache was read */
845 struct stat_validity validity;
846 };
847
848 /*
849 * Future: need to be in "struct repository"
850 * when doing a full libification.
851 */
852 static struct ref_cache {
853 struct ref_cache *next;
854 struct ref_entry *loose;
855 struct packed_ref_cache *packed;
856 /*
857 * The submodule name, or "" for the main repo. We allocate
858 * length 1 rather than FLEX_ARRAY so that the main ref_cache
859 * is initialized correctly.
860 */
861 char name[1];
862 } ref_cache, *submodule_ref_caches;
863
864 /* Lock used for the main packed-refs file: */
865 static struct lock_file packlock;
866
867 /*
868 * Increment the reference count of *packed_refs.
869 */
870 static void acquire_packed_ref_cache(struct packed_ref_cache *packed_refs)
871 {
872 packed_refs->referrers++;
873 }
874
875 /*
876 * Decrease the reference count of *packed_refs. If it goes to zero,
877 * free *packed_refs and return true; otherwise return false.
878 */
879 static int release_packed_ref_cache(struct packed_ref_cache *packed_refs)
880 {
881 if (!--packed_refs->referrers) {
882 free_ref_entry(packed_refs->root);
883 stat_validity_clear(&packed_refs->validity);
884 free(packed_refs);
885 return 1;
886 } else {
887 return 0;
888 }
889 }
890
891 static void clear_packed_ref_cache(struct ref_cache *refs)
892 {
893 if (refs->packed) {
894 struct packed_ref_cache *packed_refs = refs->packed;
895
896 if (packed_refs->lock)
897 die("internal error: packed-ref cache cleared while locked");
898 refs->packed = NULL;
899 release_packed_ref_cache(packed_refs);
900 }
901 }
902
903 static void clear_loose_ref_cache(struct ref_cache *refs)
904 {
905 if (refs->loose) {
906 free_ref_entry(refs->loose);
907 refs->loose = NULL;
908 }
909 }
910
911 static struct ref_cache *create_ref_cache(const char *submodule)
912 {
913 int len;
914 struct ref_cache *refs;
915 if (!submodule)
916 submodule = "";
917 len = strlen(submodule) + 1;
918 refs = xcalloc(1, sizeof(struct ref_cache) + len);
919 memcpy(refs->name, submodule, len);
920 return refs;
921 }
922
923 /*
924 * Return a pointer to a ref_cache for the specified submodule. For
925 * the main repository, use submodule==NULL. The returned structure
926 * will be allocated and initialized but not necessarily populated; it
927 * should not be freed.
928 */
929 static struct ref_cache *get_ref_cache(const char *submodule)
930 {
931 struct ref_cache *refs;
932
933 if (!submodule || !*submodule)
934 return &ref_cache;
935
936 for (refs = submodule_ref_caches; refs; refs = refs->next)
937 if (!strcmp(submodule, refs->name))
938 return refs;
939
940 refs = create_ref_cache(submodule);
941 refs->next = submodule_ref_caches;
942 submodule_ref_caches = refs;
943 return refs;
944 }
945
946 void invalidate_ref_cache(const char *submodule)
947 {
948 struct ref_cache *refs = get_ref_cache(submodule);
949 clear_packed_ref_cache(refs);
950 clear_loose_ref_cache(refs);
951 }
952
953 /* The length of a peeled reference line in packed-refs, including EOL: */
954 #define PEELED_LINE_LENGTH 42
955
956 /*
957 * The packed-refs header line that we write out. Perhaps other
958 * traits will be added later. The trailing space is required.
959 */
960 static const char PACKED_REFS_HEADER[] =
961 "# pack-refs with: peeled fully-peeled \n";
962
963 /*
964 * Parse one line from a packed-refs file. Write the SHA1 to sha1.
965 * Return a pointer to the refname within the line (null-terminated),
966 * or NULL if there was a problem.
967 */
968 static const char *parse_ref_line(char *line, unsigned char *sha1)
969 {
970 /*
971 * 42: the answer to everything.
972 *
973 * In this case, it happens to be the answer to
974 * 40 (length of sha1 hex representation)
975 * +1 (space in between hex and name)
976 * +1 (newline at the end of the line)
977 */
978 int len = strlen(line) - 42;
979
980 if (len <= 0)
981 return NULL;
982 if (get_sha1_hex(line, sha1) < 0)
983 return NULL;
984 if (!isspace(line[40]))
985 return NULL;
986 line += 41;
987 if (isspace(*line))
988 return NULL;
989 if (line[len] != '\n')
990 return NULL;
991 line[len] = 0;
992
993 return line;
994 }
995
996 /*
997 * Read f, which is a packed-refs file, into dir.
998 *
999 * A comment line of the form "# pack-refs with: " may contain zero or
1000 * more traits. We interpret the traits as follows:
1001 *
1002 * No traits:
1003 *
1004 * Probably no references are peeled. But if the file contains a
1005 * peeled value for a reference, we will use it.
1006 *
1007 * peeled:
1008 *
1009 * References under "refs/tags/", if they *can* be peeled, *are*
1010 * peeled in this file. References outside of "refs/tags/" are
1011 * probably not peeled even if they could have been, but if we find
1012 * a peeled value for such a reference we will use it.
1013 *
1014 * fully-peeled:
1015 *
1016 * All references in the file that can be peeled are peeled.
1017 * Inversely (and this is more important), any references in the
1018 * file for which no peeled value is recorded is not peelable. This
1019 * trait should typically be written alongside "peeled" for
1020 * compatibility with older clients, but we do not require it
1021 * (i.e., "peeled" is a no-op if "fully-peeled" is set).
1022 */
1023 static void read_packed_refs(FILE *f, struct ref_dir *dir)
1024 {
1025 struct ref_entry *last = NULL;
1026 char refline[PATH_MAX];
1027 enum { PEELED_NONE, PEELED_TAGS, PEELED_FULLY } peeled = PEELED_NONE;
1028
1029 while (fgets(refline, sizeof(refline), f)) {
1030 unsigned char sha1[20];
1031 const char *refname;
1032 static const char header[] = "# pack-refs with:";
1033
1034 if (!strncmp(refline, header, sizeof(header)-1)) {
1035 const char *traits = refline + sizeof(header) - 1;
1036 if (strstr(traits, " fully-peeled "))
1037 peeled = PEELED_FULLY;
1038 else if (strstr(traits, " peeled "))
1039 peeled = PEELED_TAGS;
1040 /* perhaps other traits later as well */
1041 continue;
1042 }
1043
1044 refname = parse_ref_line(refline, sha1);
1045 if (refname) {
1046 last = create_ref_entry(refname, sha1, REF_ISPACKED, 1);
1047 if (peeled == PEELED_FULLY ||
1048 (peeled == PEELED_TAGS && !prefixcmp(refname, "refs/tags/")))
1049 last->flag |= REF_KNOWS_PEELED;
1050 add_ref(dir, last);
1051 continue;
1052 }
1053 if (last &&
1054 refline[0] == '^' &&
1055 strlen(refline) == PEELED_LINE_LENGTH &&
1056 refline[PEELED_LINE_LENGTH - 1] == '\n' &&
1057 !get_sha1_hex(refline + 1, sha1)) {
1058 hashcpy(last->u.value.peeled, sha1);
1059 /*
1060 * Regardless of what the file header said,
1061 * we definitely know the value of *this*
1062 * reference:
1063 */
1064 last->flag |= REF_KNOWS_PEELED;
1065 }
1066 }
1067 }
1068
1069 /*
1070 * Get the packed_ref_cache for the specified ref_cache, creating it
1071 * if necessary.
1072 */
1073 static struct packed_ref_cache *get_packed_ref_cache(struct ref_cache *refs)
1074 {
1075 const char *packed_refs_file;
1076
1077 if (*refs->name)
1078 packed_refs_file = git_path_submodule(refs->name, "packed-refs");
1079 else
1080 packed_refs_file = git_path("packed-refs");
1081
1082 if (refs->packed &&
1083 !stat_validity_check(&refs->packed->validity, packed_refs_file))
1084 clear_packed_ref_cache(refs);
1085
1086 if (!refs->packed) {
1087 FILE *f;
1088
1089 refs->packed = xcalloc(1, sizeof(*refs->packed));
1090 acquire_packed_ref_cache(refs->packed);
1091 refs->packed->root = create_dir_entry(refs, "", 0, 0);
1092 f = fopen(packed_refs_file, "r");
1093 if (f) {
1094 stat_validity_update(&refs->packed->validity, fileno(f));
1095 read_packed_refs(f, get_ref_dir(refs->packed->root));
1096 fclose(f);
1097 }
1098 }
1099 return refs->packed;
1100 }
1101
1102 static struct ref_dir *get_packed_ref_dir(struct packed_ref_cache *packed_ref_cache)
1103 {
1104 return get_ref_dir(packed_ref_cache->root);
1105 }
1106
1107 static struct ref_dir *get_packed_refs(struct ref_cache *refs)
1108 {
1109 return get_packed_ref_dir(get_packed_ref_cache(refs));
1110 }
1111
1112 void add_packed_ref(const char *refname, const unsigned char *sha1)
1113 {
1114 struct packed_ref_cache *packed_ref_cache =
1115 get_packed_ref_cache(&ref_cache);
1116
1117 if (!packed_ref_cache->lock)
1118 die("internal error: packed refs not locked");
1119 add_ref(get_packed_ref_dir(packed_ref_cache),
1120 create_ref_entry(refname, sha1, REF_ISPACKED, 1));
1121 }
1122
1123 /*
1124 * Read the loose references from the namespace dirname into dir
1125 * (without recursing). dirname must end with '/'. dir must be the
1126 * directory entry corresponding to dirname.
1127 */
1128 static void read_loose_refs(const char *dirname, struct ref_dir *dir)
1129 {
1130 struct ref_cache *refs = dir->ref_cache;
1131 DIR *d;
1132 const char *path;
1133 struct dirent *de;
1134 int dirnamelen = strlen(dirname);
1135 struct strbuf refname;
1136
1137 if (*refs->name)
1138 path = git_path_submodule(refs->name, "%s", dirname);
1139 else
1140 path = git_path("%s", dirname);
1141
1142 d = opendir(path);
1143 if (!d)
1144 return;
1145
1146 strbuf_init(&refname, dirnamelen + 257);
1147 strbuf_add(&refname, dirname, dirnamelen);
1148
1149 while ((de = readdir(d)) != NULL) {
1150 unsigned char sha1[20];
1151 struct stat st;
1152 int flag;
1153 const char *refdir;
1154
1155 if (de->d_name[0] == '.')
1156 continue;
1157 if (has_extension(de->d_name, ".lock"))
1158 continue;
1159 strbuf_addstr(&refname, de->d_name);
1160 refdir = *refs->name
1161 ? git_path_submodule(refs->name, "%s", refname.buf)
1162 : git_path("%s", refname.buf);
1163 if (stat(refdir, &st) < 0) {
1164 ; /* silently ignore */
1165 } else if (S_ISDIR(st.st_mode)) {
1166 strbuf_addch(&refname, '/');
1167 add_entry_to_dir(dir,
1168 create_dir_entry(refs, refname.buf,
1169 refname.len, 1));
1170 } else {
1171 if (*refs->name) {
1172 hashclr(sha1);
1173 flag = 0;
1174 if (resolve_gitlink_ref(refs->name, refname.buf, sha1) < 0) {
1175 hashclr(sha1);
1176 flag |= REF_ISBROKEN;
1177 }
1178 } else if (read_ref_full(refname.buf, sha1, 1, &flag)) {
1179 hashclr(sha1);
1180 flag |= REF_ISBROKEN;
1181 }
1182 add_entry_to_dir(dir,
1183 create_ref_entry(refname.buf, sha1, flag, 1));
1184 }
1185 strbuf_setlen(&refname, dirnamelen);
1186 }
1187 strbuf_release(&refname);
1188 closedir(d);
1189 }
1190
1191 static struct ref_dir *get_loose_refs(struct ref_cache *refs)
1192 {
1193 if (!refs->loose) {
1194 /*
1195 * Mark the top-level directory complete because we
1196 * are about to read the only subdirectory that can
1197 * hold references:
1198 */
1199 refs->loose = create_dir_entry(refs, "", 0, 0);
1200 /*
1201 * Create an incomplete entry for "refs/":
1202 */
1203 add_entry_to_dir(get_ref_dir(refs->loose),
1204 create_dir_entry(refs, "refs/", 5, 1));
1205 }
1206 return get_ref_dir(refs->loose);
1207 }
1208
1209 /* We allow "recursive" symbolic refs. Only within reason, though */
1210 #define MAXDEPTH 5
1211 #define MAXREFLEN (1024)
1212
1213 /*
1214 * Called by resolve_gitlink_ref_recursive() after it failed to read
1215 * from the loose refs in ref_cache refs. Find <refname> in the
1216 * packed-refs file for the submodule.
1217 */
1218 static int resolve_gitlink_packed_ref(struct ref_cache *refs,
1219 const char *refname, unsigned char *sha1)
1220 {
1221 struct ref_entry *ref;
1222 struct ref_dir *dir = get_packed_refs(refs);
1223
1224 ref = find_ref(dir, refname);
1225 if (ref == NULL)
1226 return -1;
1227
1228 memcpy(sha1, ref->u.value.sha1, 20);
1229 return 0;
1230 }
1231
1232 static int resolve_gitlink_ref_recursive(struct ref_cache *refs,
1233 const char *refname, unsigned char *sha1,
1234 int recursion)
1235 {
1236 int fd, len;
1237 char buffer[128], *p;
1238 char *path;
1239
1240 if (recursion > MAXDEPTH || strlen(refname) > MAXREFLEN)
1241 return -1;
1242 path = *refs->name
1243 ? git_path_submodule(refs->name, "%s", refname)
1244 : git_path("%s", refname);
1245 fd = open(path, O_RDONLY);
1246 if (fd < 0)
1247 return resolve_gitlink_packed_ref(refs, refname, sha1);
1248
1249 len = read(fd, buffer, sizeof(buffer)-1);
1250 close(fd);
1251 if (len < 0)
1252 return -1;
1253 while (len && isspace(buffer[len-1]))
1254 len--;
1255 buffer[len] = 0;
1256
1257 /* Was it a detached head or an old-fashioned symlink? */
1258 if (!get_sha1_hex(buffer, sha1))
1259 return 0;
1260
1261 /* Symref? */
1262 if (strncmp(buffer, "ref:", 4))
1263 return -1;
1264 p = buffer + 4;
1265 while (isspace(*p))
1266 p++;
1267
1268 return resolve_gitlink_ref_recursive(refs, p, sha1, recursion+1);
1269 }
1270
1271 int resolve_gitlink_ref(const char *path, const char *refname, unsigned char *sha1)
1272 {
1273 int len = strlen(path), retval;
1274 char *submodule;
1275 struct ref_cache *refs;
1276
1277 while (len && path[len-1] == '/')
1278 len--;
1279 if (!len)
1280 return -1;
1281 submodule = xstrndup(path, len);
1282 refs = get_ref_cache(submodule);
1283 free(submodule);
1284
1285 retval = resolve_gitlink_ref_recursive(refs, refname, sha1, 0);
1286 return retval;
1287 }
1288
1289 /*
1290 * Return the ref_entry for the given refname from the packed
1291 * references. If it does not exist, return NULL.
1292 */
1293 static struct ref_entry *get_packed_ref(const char *refname)
1294 {
1295 return find_ref(get_packed_refs(&ref_cache), refname);
1296 }
1297
1298 /*
1299 * A loose ref file doesn't exist; check for a packed ref. The
1300 * options are forwarded from resolve_safe_unsafe().
1301 */
1302 static const char *handle_missing_loose_ref(const char *refname,
1303 unsigned char *sha1,
1304 int reading,
1305 int *flag)
1306 {
1307 struct ref_entry *entry;
1308
1309 /*
1310 * The loose reference file does not exist; check for a packed
1311 * reference.
1312 */
1313 entry = get_packed_ref(refname);
1314 if (entry) {
1315 hashcpy(sha1, entry->u.value.sha1);
1316 if (flag)
1317 *flag |= REF_ISPACKED;
1318 return refname;
1319 }
1320 /* The reference is not a packed reference, either. */
1321 if (reading) {
1322 return NULL;
1323 } else {
1324 hashclr(sha1);
1325 return refname;
1326 }
1327 }
1328
1329 const char *resolve_ref_unsafe(const char *refname, unsigned char *sha1, int reading, int *flag)
1330 {
1331 int depth = MAXDEPTH;
1332 ssize_t len;
1333 char buffer[256];
1334 static char refname_buffer[256];
1335
1336 if (flag)
1337 *flag = 0;
1338
1339 if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL))
1340 return NULL;
1341
1342 for (;;) {
1343 char path[PATH_MAX];
1344 struct stat st;
1345 char *buf;
1346 int fd;
1347
1348 if (--depth < 0)
1349 return NULL;
1350
1351 git_snpath(path, sizeof(path), "%s", refname);
1352
1353 /*
1354 * We might have to loop back here to avoid a race
1355 * condition: first we lstat() the file, then we try
1356 * to read it as a link or as a file. But if somebody
1357 * changes the type of the file (file <-> directory
1358 * <-> symlink) between the lstat() and reading, then
1359 * we don't want to report that as an error but rather
1360 * try again starting with the lstat().
1361 */
1362 stat_ref:
1363 if (lstat(path, &st) < 0) {
1364 if (errno == ENOENT)
1365 return handle_missing_loose_ref(refname, sha1,
1366 reading, flag);
1367 else
1368 return NULL;
1369 }
1370
1371 /* Follow "normalized" - ie "refs/.." symlinks by hand */
1372 if (S_ISLNK(st.st_mode)) {
1373 len = readlink(path, buffer, sizeof(buffer)-1);
1374 if (len < 0) {
1375 if (errno == ENOENT || errno == EINVAL)
1376 /* inconsistent with lstat; retry */
1377 goto stat_ref;
1378 else
1379 return NULL;
1380 }
1381 buffer[len] = 0;
1382 if (!prefixcmp(buffer, "refs/") &&
1383 !check_refname_format(buffer, 0)) {
1384 strcpy(refname_buffer, buffer);
1385 refname = refname_buffer;
1386 if (flag)
1387 *flag |= REF_ISSYMREF;
1388 continue;
1389 }
1390 }
1391
1392 /* Is it a directory? */
1393 if (S_ISDIR(st.st_mode)) {
1394 errno = EISDIR;
1395 return NULL;
1396 }
1397
1398 /*
1399 * Anything else, just open it and try to use it as
1400 * a ref
1401 */
1402 fd = open(path, O_RDONLY);
1403 if (fd < 0) {
1404 if (errno == ENOENT)
1405 /* inconsistent with lstat; retry */
1406 goto stat_ref;
1407 else
1408 return NULL;
1409 }
1410 len = read_in_full(fd, buffer, sizeof(buffer)-1);
1411 close(fd);
1412 if (len < 0)
1413 return NULL;
1414 while (len && isspace(buffer[len-1]))
1415 len--;
1416 buffer[len] = '\0';
1417
1418 /*
1419 * Is it a symbolic ref?
1420 */
1421 if (prefixcmp(buffer, "ref:")) {
1422 /*
1423 * Please note that FETCH_HEAD has a second
1424 * line containing other data.
1425 */
1426 if (get_sha1_hex(buffer, sha1) ||
1427 (buffer[40] != '\0' && !isspace(buffer[40]))) {
1428 if (flag)
1429 *flag |= REF_ISBROKEN;
1430 return NULL;
1431 }
1432 return refname;
1433 }
1434 if (flag)
1435 *flag |= REF_ISSYMREF;
1436 buf = buffer + 4;
1437 while (isspace(*buf))
1438 buf++;
1439 if (check_refname_format(buf, REFNAME_ALLOW_ONELEVEL)) {
1440 if (flag)
1441 *flag |= REF_ISBROKEN;
1442 return NULL;
1443 }
1444 refname = strcpy(refname_buffer, buf);
1445 }
1446 }
1447
1448 char *resolve_refdup(const char *ref, unsigned char *sha1, int reading, int *flag)
1449 {
1450 const char *ret = resolve_ref_unsafe(ref, sha1, reading, flag);
1451 return ret ? xstrdup(ret) : NULL;
1452 }
1453
1454 /* The argument to filter_refs */
1455 struct ref_filter {
1456 const char *pattern;
1457 each_ref_fn *fn;
1458 void *cb_data;
1459 };
1460
1461 int read_ref_full(const char *refname, unsigned char *sha1, int reading, int *flags)
1462 {
1463 if (resolve_ref_unsafe(refname, sha1, reading, flags))
1464 return 0;
1465 return -1;
1466 }
1467
1468 int read_ref(const char *refname, unsigned char *sha1)
1469 {
1470 return read_ref_full(refname, sha1, 1, NULL);
1471 }
1472
1473 int ref_exists(const char *refname)
1474 {
1475 unsigned char sha1[20];
1476 return !!resolve_ref_unsafe(refname, sha1, 1, NULL);
1477 }
1478
1479 static int filter_refs(const char *refname, const unsigned char *sha1, int flags,
1480 void *data)
1481 {
1482 struct ref_filter *filter = (struct ref_filter *)data;
1483 if (fnmatch(filter->pattern, refname, 0))
1484 return 0;
1485 return filter->fn(refname, sha1, flags, filter->cb_data);
1486 }
1487
1488 enum peel_status {
1489 /* object was peeled successfully: */
1490 PEEL_PEELED = 0,
1491
1492 /*
1493 * object cannot be peeled because the named object (or an
1494 * object referred to by a tag in the peel chain), does not
1495 * exist.
1496 */
1497 PEEL_INVALID = -1,
1498
1499 /* object cannot be peeled because it is not a tag: */
1500 PEEL_NON_TAG = -2,
1501
1502 /* ref_entry contains no peeled value because it is a symref: */
1503 PEEL_IS_SYMREF = -3,
1504
1505 /*
1506 * ref_entry cannot be peeled because it is broken (i.e., the
1507 * symbolic reference cannot even be resolved to an object
1508 * name):
1509 */
1510 PEEL_BROKEN = -4
1511 };
1512
1513 /*
1514 * Peel the named object; i.e., if the object is a tag, resolve the
1515 * tag recursively until a non-tag is found. If successful, store the
1516 * result to sha1 and return PEEL_PEELED. If the object is not a tag
1517 * or is not valid, return PEEL_NON_TAG or PEEL_INVALID, respectively,
1518 * and leave sha1 unchanged.
1519 */
1520 static enum peel_status peel_object(const unsigned char *name, unsigned char *sha1)
1521 {
1522 struct object *o = lookup_unknown_object(name);
1523
1524 if (o->type == OBJ_NONE) {
1525 int type = sha1_object_info(name, NULL);
1526 if (type < 0)
1527 return PEEL_INVALID;
1528 o->type = type;
1529 }
1530
1531 if (o->type != OBJ_TAG)
1532 return PEEL_NON_TAG;
1533
1534 o = deref_tag_noverify(o);
1535 if (!o)
1536 return PEEL_INVALID;
1537
1538 hashcpy(sha1, o->sha1);
1539 return PEEL_PEELED;
1540 }
1541
1542 /*
1543 * Peel the entry (if possible) and return its new peel_status. If
1544 * repeel is true, re-peel the entry even if there is an old peeled
1545 * value that is already stored in it.
1546 *
1547 * It is OK to call this function with a packed reference entry that
1548 * might be stale and might even refer to an object that has since
1549 * been garbage-collected. In such a case, if the entry has
1550 * REF_KNOWS_PEELED then leave the status unchanged and return
1551 * PEEL_PEELED or PEEL_NON_TAG; otherwise, return PEEL_INVALID.
1552 */
1553 static enum peel_status peel_entry(struct ref_entry *entry, int repeel)
1554 {
1555 enum peel_status status;
1556
1557 if (entry->flag & REF_KNOWS_PEELED) {
1558 if (repeel) {
1559 entry->flag &= ~REF_KNOWS_PEELED;
1560 hashclr(entry->u.value.peeled);
1561 } else {
1562 return is_null_sha1(entry->u.value.peeled) ?
1563 PEEL_NON_TAG : PEEL_PEELED;
1564 }
1565 }
1566 if (entry->flag & REF_ISBROKEN)
1567 return PEEL_BROKEN;
1568 if (entry->flag & REF_ISSYMREF)
1569 return PEEL_IS_SYMREF;
1570
1571 status = peel_object(entry->u.value.sha1, entry->u.value.peeled);
1572 if (status == PEEL_PEELED || status == PEEL_NON_TAG)
1573 entry->flag |= REF_KNOWS_PEELED;
1574 return status;
1575 }
1576
1577 int peel_ref(const char *refname, unsigned char *sha1)
1578 {
1579 int flag;
1580 unsigned char base[20];
1581
1582 if (current_ref && (current_ref->name == refname
1583 || !strcmp(current_ref->name, refname))) {
1584 if (peel_entry(current_ref, 0))
1585 return -1;
1586 hashcpy(sha1, current_ref->u.value.peeled);
1587 return 0;
1588 }
1589
1590 if (read_ref_full(refname, base, 1, &flag))
1591 return -1;
1592
1593 /*
1594 * If the reference is packed, read its ref_entry from the
1595 * cache in the hope that we already know its peeled value.
1596 * We only try this optimization on packed references because
1597 * (a) forcing the filling of the loose reference cache could
1598 * be expensive and (b) loose references anyway usually do not
1599 * have REF_KNOWS_PEELED.
1600 */
1601 if (flag & REF_ISPACKED) {
1602 struct ref_entry *r = get_packed_ref(refname);
1603 if (r) {
1604 if (peel_entry(r, 0))
1605 return -1;
1606 hashcpy(sha1, r->u.value.peeled);
1607 return 0;
1608 }
1609 }
1610
1611 return peel_object(base, sha1);
1612 }
1613
1614 struct warn_if_dangling_data {
1615 FILE *fp;
1616 const char *refname;
1617 const char *msg_fmt;
1618 };
1619
1620 static int warn_if_dangling_symref(const char *refname, const unsigned char *sha1,
1621 int flags, void *cb_data)
1622 {
1623 struct warn_if_dangling_data *d = cb_data;
1624 const char *resolves_to;
1625 unsigned char junk[20];
1626
1627 if (!(flags & REF_ISSYMREF))
1628 return 0;
1629
1630 resolves_to = resolve_ref_unsafe(refname, junk, 0, NULL);
1631 if (!resolves_to || strcmp(resolves_to, d->refname))
1632 return 0;
1633
1634 fprintf(d->fp, d->msg_fmt, refname);
1635 fputc('\n', d->fp);
1636 return 0;
1637 }
1638
1639 void warn_dangling_symref(FILE *fp, const char *msg_fmt, const char *refname)
1640 {
1641 struct warn_if_dangling_data data;
1642
1643 data.fp = fp;
1644 data.refname = refname;
1645 data.msg_fmt = msg_fmt;
1646 for_each_rawref(warn_if_dangling_symref, &data);
1647 }
1648
1649 /*
1650 * Call fn for each reference in the specified ref_cache, omitting
1651 * references not in the containing_dir of base. fn is called for all
1652 * references, including broken ones. If fn ever returns a non-zero
1653 * value, stop the iteration and return that value; otherwise, return
1654 * 0.
1655 */
1656 static int do_for_each_entry(struct ref_cache *refs, const char *base,
1657 each_ref_entry_fn fn, void *cb_data)
1658 {
1659 struct packed_ref_cache *packed_ref_cache;
1660 struct ref_dir *loose_dir;
1661 struct ref_dir *packed_dir;
1662 int retval = 0;
1663
1664 /*
1665 * We must make sure that all loose refs are read before accessing the
1666 * packed-refs file; this avoids a race condition in which loose refs
1667 * are migrated to the packed-refs file by a simultaneous process, but
1668 * our in-memory view is from before the migration. get_packed_ref_cache()
1669 * takes care of making sure our view is up to date with what is on
1670 * disk.
1671 */
1672 loose_dir = get_loose_refs(refs);
1673 if (base && *base) {
1674 loose_dir = find_containing_dir(loose_dir, base, 0);
1675 }
1676 if (loose_dir)
1677 prime_ref_dir(loose_dir);
1678
1679 packed_ref_cache = get_packed_ref_cache(refs);
1680 acquire_packed_ref_cache(packed_ref_cache);
1681 packed_dir = get_packed_ref_dir(packed_ref_cache);
1682 if (base && *base) {
1683 packed_dir = find_containing_dir(packed_dir, base, 0);
1684 }
1685
1686 if (packed_dir && loose_dir) {
1687 sort_ref_dir(packed_dir);
1688 sort_ref_dir(loose_dir);
1689 retval = do_for_each_entry_in_dirs(
1690 packed_dir, loose_dir, fn, cb_data);
1691 } else if (packed_dir) {
1692 sort_ref_dir(packed_dir);
1693 retval = do_for_each_entry_in_dir(
1694 packed_dir, 0, fn, cb_data);
1695 } else if (loose_dir) {
1696 sort_ref_dir(loose_dir);
1697 retval = do_for_each_entry_in_dir(
1698 loose_dir, 0, fn, cb_data);
1699 }
1700
1701 release_packed_ref_cache(packed_ref_cache);
1702 return retval;
1703 }
1704
1705 /*
1706 * Call fn for each reference in the specified ref_cache for which the
1707 * refname begins with base. If trim is non-zero, then trim that many
1708 * characters off the beginning of each refname before passing the
1709 * refname to fn. flags can be DO_FOR_EACH_INCLUDE_BROKEN to include
1710 * broken references in the iteration. If fn ever returns a non-zero
1711 * value, stop the iteration and return that value; otherwise, return
1712 * 0.
1713 */
1714 static int do_for_each_ref(struct ref_cache *refs, const char *base,
1715 each_ref_fn fn, int trim, int flags, void *cb_data)
1716 {
1717 struct ref_entry_cb data;
1718 data.base = base;
1719 data.trim = trim;
1720 data.flags = flags;
1721 data.fn = fn;
1722 data.cb_data = cb_data;
1723
1724 return do_for_each_entry(refs, base, do_one_ref, &data);
1725 }
1726
1727 static int do_head_ref(const char *submodule, each_ref_fn fn, void *cb_data)
1728 {
1729 unsigned char sha1[20];
1730 int flag;
1731
1732 if (submodule) {
1733 if (resolve_gitlink_ref(submodule, "HEAD", sha1) == 0)
1734 return fn("HEAD", sha1, 0, cb_data);
1735
1736 return 0;
1737 }
1738
1739 if (!read_ref_full("HEAD", sha1, 1, &flag))
1740 return fn("HEAD", sha1, flag, cb_data);
1741
1742 return 0;
1743 }
1744
1745 int head_ref(each_ref_fn fn, void *cb_data)
1746 {
1747 return do_head_ref(NULL, fn, cb_data);
1748 }
1749
1750 int head_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
1751 {
1752 return do_head_ref(submodule, fn, cb_data);
1753 }
1754
1755 int for_each_ref(each_ref_fn fn, void *cb_data)
1756 {
1757 return do_for_each_ref(&ref_cache, "", fn, 0, 0, cb_data);
1758 }
1759
1760 int for_each_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
1761 {
1762 return do_for_each_ref(get_ref_cache(submodule), "", fn, 0, 0, cb_data);
1763 }
1764
1765 int for_each_ref_in(const char *prefix, each_ref_fn fn, void *cb_data)
1766 {
1767 return do_for_each_ref(&ref_cache, prefix, fn, strlen(prefix), 0, cb_data);
1768 }
1769
1770 int for_each_ref_in_submodule(const char *submodule, const char *prefix,
1771 each_ref_fn fn, void *cb_data)
1772 {
1773 return do_for_each_ref(get_ref_cache(submodule), prefix, fn, strlen(prefix), 0, cb_data);
1774 }
1775
1776 int for_each_tag_ref(each_ref_fn fn, void *cb_data)
1777 {
1778 return for_each_ref_in("refs/tags/", fn, cb_data);
1779 }
1780
1781 int for_each_tag_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
1782 {
1783 return for_each_ref_in_submodule(submodule, "refs/tags/", fn, cb_data);
1784 }
1785
1786 int for_each_branch_ref(each_ref_fn fn, void *cb_data)
1787 {
1788 return for_each_ref_in("refs/heads/", fn, cb_data);
1789 }
1790
1791 int for_each_branch_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
1792 {
1793 return for_each_ref_in_submodule(submodule, "refs/heads/", fn, cb_data);
1794 }
1795
1796 int for_each_remote_ref(each_ref_fn fn, void *cb_data)
1797 {
1798 return for_each_ref_in("refs/remotes/", fn, cb_data);
1799 }
1800
1801 int for_each_remote_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
1802 {
1803 return for_each_ref_in_submodule(submodule, "refs/remotes/", fn, cb_data);
1804 }
1805
1806 int for_each_replace_ref(each_ref_fn fn, void *cb_data)
1807 {
1808 return do_for_each_ref(&ref_cache, "refs/replace/", fn, 13, 0, cb_data);
1809 }
1810
1811 int head_ref_namespaced(each_ref_fn fn, void *cb_data)
1812 {
1813 struct strbuf buf = STRBUF_INIT;
1814 int ret = 0;
1815 unsigned char sha1[20];
1816 int flag;
1817
1818 strbuf_addf(&buf, "%sHEAD", get_git_namespace());
1819 if (!read_ref_full(buf.buf, sha1, 1, &flag))
1820 ret = fn(buf.buf, sha1, flag, cb_data);
1821 strbuf_release(&buf);
1822
1823 return ret;
1824 }
1825
1826 int for_each_namespaced_ref(each_ref_fn fn, void *cb_data)
1827 {
1828 struct strbuf buf = STRBUF_INIT;
1829 int ret;
1830 strbuf_addf(&buf, "%srefs/", get_git_namespace());
1831 ret = do_for_each_ref(&ref_cache, buf.buf, fn, 0, 0, cb_data);
1832 strbuf_release(&buf);
1833 return ret;
1834 }
1835
1836 int for_each_glob_ref_in(each_ref_fn fn, const char *pattern,
1837 const char *prefix, void *cb_data)
1838 {
1839 struct strbuf real_pattern = STRBUF_INIT;
1840 struct ref_filter filter;
1841 int ret;
1842
1843 if (!prefix && prefixcmp(pattern, "refs/"))
1844 strbuf_addstr(&real_pattern, "refs/");
1845 else if (prefix)
1846 strbuf_addstr(&real_pattern, prefix);
1847 strbuf_addstr(&real_pattern, pattern);
1848
1849 if (!has_glob_specials(pattern)) {
1850 /* Append implied '/' '*' if not present. */
1851 if (real_pattern.buf[real_pattern.len - 1] != '/')
1852 strbuf_addch(&real_pattern, '/');
1853 /* No need to check for '*', there is none. */
1854 strbuf_addch(&real_pattern, '*');
1855 }
1856
1857 filter.pattern = real_pattern.buf;
1858 filter.fn = fn;
1859 filter.cb_data = cb_data;
1860 ret = for_each_ref(filter_refs, &filter);
1861
1862 strbuf_release(&real_pattern);
1863 return ret;
1864 }
1865
1866 int for_each_glob_ref(each_ref_fn fn, const char *pattern, void *cb_data)
1867 {
1868 return for_each_glob_ref_in(fn, pattern, NULL, cb_data);
1869 }
1870
1871 int for_each_rawref(each_ref_fn fn, void *cb_data)
1872 {
1873 return do_for_each_ref(&ref_cache, "", fn, 0,
1874 DO_FOR_EACH_INCLUDE_BROKEN, cb_data);
1875 }
1876
1877 const char *prettify_refname(const char *name)
1878 {
1879 return name + (
1880 !prefixcmp(name, "refs/heads/") ? 11 :
1881 !prefixcmp(name, "refs/tags/") ? 10 :
1882 !prefixcmp(name, "refs/remotes/") ? 13 :
1883 0);
1884 }
1885
1886 const char *ref_rev_parse_rules[] = {
1887 "%.*s",
1888 "refs/%.*s",
1889 "refs/tags/%.*s",
1890 "refs/heads/%.*s",
1891 "refs/remotes/%.*s",
1892 "refs/remotes/%.*s/HEAD",
1893 NULL
1894 };
1895
1896 int refname_match(const char *abbrev_name, const char *full_name, const char **rules)
1897 {
1898 const char **p;
1899 const int abbrev_name_len = strlen(abbrev_name);
1900
1901 for (p = rules; *p; p++) {
1902 if (!strcmp(full_name, mkpath(*p, abbrev_name_len, abbrev_name))) {
1903 return 1;
1904 }
1905 }
1906
1907 return 0;
1908 }
1909
1910 static struct ref_lock *verify_lock(struct ref_lock *lock,
1911 const unsigned char *old_sha1, int mustexist)
1912 {
1913 if (read_ref_full(lock->ref_name, lock->old_sha1, mustexist, NULL)) {
1914 error("Can't verify ref %s", lock->ref_name);
1915 unlock_ref(lock);
1916 return NULL;
1917 }
1918 if (hashcmp(lock->old_sha1, old_sha1)) {
1919 error("Ref %s is at %s but expected %s", lock->ref_name,
1920 sha1_to_hex(lock->old_sha1), sha1_to_hex(old_sha1));
1921 unlock_ref(lock);
1922 return NULL;
1923 }
1924 return lock;
1925 }
1926
1927 static int remove_empty_directories(const char *file)
1928 {
1929 /* we want to create a file but there is a directory there;
1930 * if that is an empty directory (or a directory that contains
1931 * only empty directories), remove them.
1932 */
1933 struct strbuf path;
1934 int result;
1935
1936 strbuf_init(&path, 20);
1937 strbuf_addstr(&path, file);
1938
1939 result = remove_dir_recursively(&path, REMOVE_DIR_EMPTY_ONLY);
1940
1941 strbuf_release(&path);
1942
1943 return result;
1944 }
1945
1946 /*
1947 * *string and *len will only be substituted, and *string returned (for
1948 * later free()ing) if the string passed in is a magic short-hand form
1949 * to name a branch.
1950 */
1951 static char *substitute_branch_name(const char **string, int *len)
1952 {
1953 struct strbuf buf = STRBUF_INIT;
1954 int ret = interpret_branch_name(*string, &buf);
1955
1956 if (ret == *len) {
1957 size_t size;
1958 *string = strbuf_detach(&buf, &size);
1959 *len = size;
1960 return (char *)*string;
1961 }
1962
1963 return NULL;
1964 }
1965
1966 int dwim_ref(const char *str, int len, unsigned char *sha1, char **ref)
1967 {
1968 char *last_branch = substitute_branch_name(&str, &len);
1969 const char **p, *r;
1970 int refs_found = 0;
1971
1972 *ref = NULL;
1973 for (p = ref_rev_parse_rules; *p; p++) {
1974 char fullref[PATH_MAX];
1975 unsigned char sha1_from_ref[20];
1976 unsigned char *this_result;
1977 int flag;
1978
1979 this_result = refs_found ? sha1_from_ref : sha1;
1980 mksnpath(fullref, sizeof(fullref), *p, len, str);
1981 r = resolve_ref_unsafe(fullref, this_result, 1, &flag);
1982 if (r) {
1983 if (!refs_found++)
1984 *ref = xstrdup(r);
1985 if (!warn_ambiguous_refs)
1986 break;
1987 } else if ((flag & REF_ISSYMREF) && strcmp(fullref, "HEAD")) {
1988 warning("ignoring dangling symref %s.", fullref);
1989 } else if ((flag & REF_ISBROKEN) && strchr(fullref, '/')) {
1990 warning("ignoring broken ref %s.", fullref);
1991 }
1992 }
1993 free(last_branch);
1994 return refs_found;
1995 }
1996
1997 int dwim_log(const char *str, int len, unsigned char *sha1, char **log)
1998 {
1999 char *last_branch = substitute_branch_name(&str, &len);
2000 const char **p;
2001 int logs_found = 0;
2002
2003 *log = NULL;
2004 for (p = ref_rev_parse_rules; *p; p++) {
2005 struct stat st;
2006 unsigned char hash[20];
2007 char path[PATH_MAX];
2008 const char *ref, *it;
2009
2010 mksnpath(path, sizeof(path), *p, len, str);
2011 ref = resolve_ref_unsafe(path, hash, 1, NULL);
2012 if (!ref)
2013 continue;
2014 if (!stat(git_path("logs/%s", path), &st) &&
2015 S_ISREG(st.st_mode))
2016 it = path;
2017 else if (strcmp(ref, path) &&
2018 !stat(git_path("logs/%s", ref), &st) &&
2019 S_ISREG(st.st_mode))
2020 it = ref;
2021 else
2022 continue;
2023 if (!logs_found++) {
2024 *log = xstrdup(it);
2025 hashcpy(sha1, hash);
2026 }
2027 if (!warn_ambiguous_refs)
2028 break;
2029 }
2030 free(last_branch);
2031 return logs_found;
2032 }
2033
2034 static struct ref_lock *lock_ref_sha1_basic(const char *refname,
2035 const unsigned char *old_sha1,
2036 int flags, int *type_p)
2037 {
2038 char *ref_file;
2039 const char *orig_refname = refname;
2040 struct ref_lock *lock;
2041 int last_errno = 0;
2042 int type, lflags;
2043 int mustexist = (old_sha1 && !is_null_sha1(old_sha1));
2044 int missing = 0;
2045
2046 lock = xcalloc(1, sizeof(struct ref_lock));
2047 lock->lock_fd = -1;
2048
2049 refname = resolve_ref_unsafe(refname, lock->old_sha1, mustexist, &type);
2050 if (!refname && errno == EISDIR) {
2051 /* we are trying to lock foo but we used to
2052 * have foo/bar which now does not exist;
2053 * it is normal for the empty directory 'foo'
2054 * to remain.
2055 */
2056 ref_file = git_path("%s", orig_refname);
2057 if (remove_empty_directories(ref_file)) {
2058 last_errno = errno;
2059 error("there are still refs under '%s'", orig_refname);
2060 goto error_return;
2061 }
2062 refname = resolve_ref_unsafe(orig_refname, lock->old_sha1, mustexist, &type);
2063 }
2064 if (type_p)
2065 *type_p = type;
2066 if (!refname) {
2067 last_errno = errno;
2068 error("unable to resolve reference %s: %s",
2069 orig_refname, strerror(errno));
2070 goto error_return;
2071 }
2072 missing = is_null_sha1(lock->old_sha1);
2073 /* When the ref did not exist and we are creating it,
2074 * make sure there is no existing ref that is packed
2075 * whose name begins with our refname, nor a ref whose
2076 * name is a proper prefix of our refname.
2077 */
2078 if (missing &&
2079 !is_refname_available(refname, NULL, get_packed_refs(&ref_cache))) {
2080 last_errno = ENOTDIR;
2081 goto error_return;
2082 }
2083
2084 lock->lk = xcalloc(1, sizeof(struct lock_file));
2085
2086 lflags = LOCK_DIE_ON_ERROR;
2087 if (flags & REF_NODEREF) {
2088 refname = orig_refname;
2089 lflags |= LOCK_NODEREF;
2090 }
2091 lock->ref_name = xstrdup(refname);
2092 lock->orig_ref_name = xstrdup(orig_refname);
2093 ref_file = git_path("%s", refname);
2094 if (missing)
2095 lock->force_write = 1;
2096 if ((flags & REF_NODEREF) && (type & REF_ISSYMREF))
2097 lock->force_write = 1;
2098
2099 if (safe_create_leading_directories(ref_file)) {
2100 last_errno = errno;
2101 error("unable to create directory for %s", ref_file);
2102 goto error_return;
2103 }
2104
2105 lock->lock_fd = hold_lock_file_for_update(lock->lk, ref_file, lflags);
2106 return old_sha1 ? verify_lock(lock, old_sha1, mustexist) : lock;
2107
2108 error_return:
2109 unlock_ref(lock);
2110 errno = last_errno;
2111 return NULL;
2112 }
2113
2114 struct ref_lock *lock_ref_sha1(const char *refname, const unsigned char *old_sha1)
2115 {
2116 char refpath[PATH_MAX];
2117 if (check_refname_format(refname, 0))
2118 return NULL;
2119 strcpy(refpath, mkpath("refs/%s", refname));
2120 return lock_ref_sha1_basic(refpath, old_sha1, 0, NULL);
2121 }
2122
2123 struct ref_lock *lock_any_ref_for_update(const char *refname,
2124 const unsigned char *old_sha1, int flags)
2125 {
2126 if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL))
2127 return NULL;
2128 return lock_ref_sha1_basic(refname, old_sha1, flags, NULL);
2129 }
2130
2131 /*
2132 * Write an entry to the packed-refs file for the specified refname.
2133 * If peeled is non-NULL, write it as the entry's peeled value.
2134 */
2135 static void write_packed_entry(int fd, char *refname, unsigned char *sha1,
2136 unsigned char *peeled)
2137 {
2138 char line[PATH_MAX + 100];
2139 int len;
2140
2141 len = snprintf(line, sizeof(line), "%s %s\n",
2142 sha1_to_hex(sha1), refname);
2143 /* this should not happen but just being defensive */
2144 if (len > sizeof(line))
2145 die("too long a refname '%s'", refname);
2146 write_or_die(fd, line, len);
2147
2148 if (peeled) {
2149 if (snprintf(line, sizeof(line), "^%s\n",
2150 sha1_to_hex(peeled)) != PEELED_LINE_LENGTH)
2151 die("internal error");
2152 write_or_die(fd, line, PEELED_LINE_LENGTH);
2153 }
2154 }
2155
2156 /*
2157 * An each_ref_entry_fn that writes the entry to a packed-refs file.
2158 */
2159 static int write_packed_entry_fn(struct ref_entry *entry, void *cb_data)
2160 {
2161 int *fd = cb_data;
2162 enum peel_status peel_status = peel_entry(entry, 0);
2163
2164 if (peel_status != PEEL_PEELED && peel_status != PEEL_NON_TAG)
2165 error("internal error: %s is not a valid packed reference!",
2166 entry->name);
2167 write_packed_entry(*fd, entry->name, entry->u.value.sha1,
2168 peel_status == PEEL_PEELED ?
2169 entry->u.value.peeled : NULL);
2170 return 0;
2171 }
2172
2173 int lock_packed_refs(int flags)
2174 {
2175 struct packed_ref_cache *packed_ref_cache;
2176
2177 if (hold_lock_file_for_update(&packlock, git_path("packed-refs"), flags) < 0)
2178 return -1;
2179 /*
2180 * Get the current packed-refs while holding the lock. If the
2181 * packed-refs file has been modified since we last read it,
2182 * this will automatically invalidate the cache and re-read
2183 * the packed-refs file.
2184 */
2185 packed_ref_cache = get_packed_ref_cache(&ref_cache);
2186 packed_ref_cache->lock = &packlock;
2187 /* Increment the reference count to prevent it from being freed: */
2188 acquire_packed_ref_cache(packed_ref_cache);
2189 return 0;
2190 }
2191
2192 int commit_packed_refs(void)
2193 {
2194 struct packed_ref_cache *packed_ref_cache =
2195 get_packed_ref_cache(&ref_cache);
2196 int error = 0;
2197
2198 if (!packed_ref_cache->lock)
2199 die("internal error: packed-refs not locked");
2200 write_or_die(packed_ref_cache->lock->fd,
2201 PACKED_REFS_HEADER, strlen(PACKED_REFS_HEADER));
2202
2203 do_for_each_entry_in_dir(get_packed_ref_dir(packed_ref_cache),
2204 0, write_packed_entry_fn,
2205 &packed_ref_cache->lock->fd);
2206 if (commit_lock_file(packed_ref_cache->lock))
2207 error = -1;
2208 packed_ref_cache->lock = NULL;
2209 release_packed_ref_cache(packed_ref_cache);
2210 return error;
2211 }
2212
2213 void rollback_packed_refs(void)
2214 {
2215 struct packed_ref_cache *packed_ref_cache =
2216 get_packed_ref_cache(&ref_cache);
2217
2218 if (!packed_ref_cache->lock)
2219 die("internal error: packed-refs not locked");
2220 rollback_lock_file(packed_ref_cache->lock);
2221 packed_ref_cache->lock = NULL;
2222 release_packed_ref_cache(packed_ref_cache);
2223 clear_packed_ref_cache(&ref_cache);
2224 }
2225
2226 struct ref_to_prune {
2227 struct ref_to_prune *next;
2228 unsigned char sha1[20];
2229 char name[FLEX_ARRAY];
2230 };
2231
2232 struct pack_refs_cb_data {
2233 unsigned int flags;
2234 struct ref_dir *packed_refs;
2235 struct ref_to_prune *ref_to_prune;
2236 };
2237
2238 /*
2239 * An each_ref_entry_fn that is run over loose references only. If
2240 * the loose reference can be packed, add an entry in the packed ref
2241 * cache. If the reference should be pruned, also add it to
2242 * ref_to_prune in the pack_refs_cb_data.
2243 */
2244 static int pack_if_possible_fn(struct ref_entry *entry, void *cb_data)
2245 {
2246 struct pack_refs_cb_data *cb = cb_data;
2247 enum peel_status peel_status;
2248 struct ref_entry *packed_entry;
2249 int is_tag_ref = !prefixcmp(entry->name, "refs/tags/");
2250
2251 /* ALWAYS pack tags */
2252 if (!(cb->flags & PACK_REFS_ALL) && !is_tag_ref)
2253 return 0;
2254
2255 /* Do not pack symbolic or broken refs: */
2256 if ((entry->flag & REF_ISSYMREF) || !ref_resolves_to_object(entry))
2257 return 0;
2258
2259 /* Add a packed ref cache entry equivalent to the loose entry. */
2260 peel_status = peel_entry(entry, 1);
2261 if (peel_status != PEEL_PEELED && peel_status != PEEL_NON_TAG)
2262 die("internal error peeling reference %s (%s)",
2263 entry->name, sha1_to_hex(entry->u.value.sha1));
2264 packed_entry = find_ref(cb->packed_refs, entry->name);
2265 if (packed_entry) {
2266 /* Overwrite existing packed entry with info from loose entry */
2267 packed_entry->flag = REF_ISPACKED | REF_KNOWS_PEELED;
2268 hashcpy(packed_entry->u.value.sha1, entry->u.value.sha1);
2269 } else {
2270 packed_entry = create_ref_entry(entry->name, entry->u.value.sha1,
2271 REF_ISPACKED | REF_KNOWS_PEELED, 0);
2272 add_ref(cb->packed_refs, packed_entry);
2273 }
2274 hashcpy(packed_entry->u.value.peeled, entry->u.value.peeled);
2275
2276 /* Schedule the loose reference for pruning if requested. */
2277 if ((cb->flags & PACK_REFS_PRUNE)) {
2278 int namelen = strlen(entry->name) + 1;
2279 struct ref_to_prune *n = xcalloc(1, sizeof(*n) + namelen);
2280 hashcpy(n->sha1, entry->u.value.sha1);
2281 strcpy(n->name, entry->name);
2282 n->next = cb->ref_to_prune;
2283 cb->ref_to_prune = n;
2284 }
2285 return 0;
2286 }
2287
2288 /*
2289 * Remove empty parents, but spare refs/ and immediate subdirs.
2290 * Note: munges *name.
2291 */
2292 static void try_remove_empty_parents(char *name)
2293 {
2294 char *p, *q;
2295 int i;
2296 p = name;
2297 for (i = 0; i < 2; i++) { /* refs/{heads,tags,...}/ */
2298 while (*p && *p != '/')
2299 p++;
2300 /* tolerate duplicate slashes; see check_refname_format() */
2301 while (*p == '/')
2302 p++;
2303 }
2304 for (q = p; *q; q++)
2305 ;
2306 while (1) {
2307 while (q > p && *q != '/')
2308 q--;
2309 while (q > p && *(q-1) == '/')
2310 q--;
2311 if (q == p)
2312 break;
2313 *q = '\0';
2314 if (rmdir(git_path("%s", name)))
2315 break;
2316 }
2317 }
2318
2319 /* make sure nobody touched the ref, and unlink */
2320 static void prune_ref(struct ref_to_prune *r)
2321 {
2322 struct ref_lock *lock = lock_ref_sha1(r->name + 5, r->sha1);
2323
2324 if (lock) {
2325 unlink_or_warn(git_path("%s", r->name));
2326 unlock_ref(lock);
2327 try_remove_empty_parents(r->name);
2328 }
2329 }
2330
2331 static void prune_refs(struct ref_to_prune *r)
2332 {
2333 while (r) {
2334 prune_ref(r);
2335 r = r->next;
2336 }
2337 }
2338
2339 int pack_refs(unsigned int flags)
2340 {
2341 struct pack_refs_cb_data cbdata;
2342
2343 memset(&cbdata, 0, sizeof(cbdata));
2344 cbdata.flags = flags;
2345
2346 lock_packed_refs(LOCK_DIE_ON_ERROR);
2347 cbdata.packed_refs = get_packed_refs(&ref_cache);
2348
2349 do_for_each_entry_in_dir(get_loose_refs(&ref_cache), 0,
2350 pack_if_possible_fn, &cbdata);
2351
2352 if (commit_packed_refs())
2353 die_errno("unable to overwrite old ref-pack file");
2354
2355 prune_refs(cbdata.ref_to_prune);
2356 return 0;
2357 }
2358
2359 /*
2360 * If entry is no longer needed in packed-refs, add it to the string
2361 * list pointed to by cb_data. Reasons for deleting entries:
2362 *
2363 * - Entry is broken.
2364 * - Entry is overridden by a loose ref.
2365 * - Entry does not point at a valid object.
2366 *
2367 * In the first and third cases, also emit an error message because these
2368 * are indications of repository corruption.
2369 */
2370 static int curate_packed_ref_fn(struct ref_entry *entry, void *cb_data)
2371 {
2372 struct string_list *refs_to_delete = cb_data;
2373
2374 if (entry->flag & REF_ISBROKEN) {
2375 /* This shouldn't happen to packed refs. */
2376 error("%s is broken!", entry->name);
2377 string_list_append(refs_to_delete, entry->name);
2378 return 0;
2379 }
2380 if (!has_sha1_file(entry->u.value.sha1)) {
2381 unsigned char sha1[20];
2382 int flags;
2383
2384 if (read_ref_full(entry->name, sha1, 0, &flags))
2385 /* We should at least have found the packed ref. */
2386 die("Internal error");
2387 if ((flags & REF_ISSYMREF) || !(flags & REF_ISPACKED)) {
2388 /*
2389 * This packed reference is overridden by a
2390 * loose reference, so it is OK that its value
2391 * is no longer valid; for example, it might
2392 * refer to an object that has been garbage
2393 * collected. For this purpose we don't even
2394 * care whether the loose reference itself is
2395 * invalid, broken, symbolic, etc. Silently
2396 * remove the packed reference.
2397 */
2398 string_list_append(refs_to_delete, entry->name);
2399 return 0;
2400 }
2401 /*
2402 * There is no overriding loose reference, so the fact
2403 * that this reference doesn't refer to a valid object
2404 * indicates some kind of repository corruption.
2405 * Report the problem, then omit the reference from
2406 * the output.
2407 */
2408 error("%s does not point to a valid object!", entry->name);
2409 string_list_append(refs_to_delete, entry->name);
2410 return 0;
2411 }
2412
2413 return 0;
2414 }
2415
2416 static int repack_without_ref(const char *refname)
2417 {
2418 struct ref_dir *packed;
2419 struct string_list refs_to_delete = STRING_LIST_INIT_DUP;
2420 struct string_list_item *ref_to_delete;
2421
2422 if (!get_packed_ref(refname))
2423 return 0; /* refname does not exist in packed refs */
2424
2425 if (lock_packed_refs(0)) {
2426 unable_to_lock_error(git_path("packed-refs"), errno);
2427 return error("cannot delete '%s' from packed refs", refname);
2428 }
2429 packed = get_packed_refs(&ref_cache);
2430
2431 /* Remove refname from the cache: */
2432 if (remove_entry(packed, refname) == -1) {
2433 /*
2434 * The packed entry disappeared while we were
2435 * acquiring the lock.
2436 */
2437 rollback_packed_refs();
2438 return 0;
2439 }
2440
2441 /* Remove any other accumulated cruft: */
2442 do_for_each_entry_in_dir(packed, 0, curate_packed_ref_fn, &refs_to_delete);
2443 for_each_string_list_item(ref_to_delete, &refs_to_delete) {
2444 if (remove_entry(packed, ref_to_delete->string) == -1)
2445 die("internal error");
2446 }
2447
2448 /* Write what remains: */
2449 return commit_packed_refs();
2450 }
2451
2452 int delete_ref(const char *refname, const unsigned char *sha1, int delopt)
2453 {
2454 struct ref_lock *lock;
2455 int err, i = 0, ret = 0, flag = 0;
2456
2457 lock = lock_ref_sha1_basic(refname, sha1, delopt, &flag);
2458 if (!lock)
2459 return 1;
2460 if (!(flag & REF_ISPACKED) || flag & REF_ISSYMREF) {
2461 /* loose */
2462 i = strlen(lock->lk->filename) - 5; /* .lock */
2463 lock->lk->filename[i] = 0;
2464 err = unlink_or_warn(lock->lk->filename);
2465 if (err && errno != ENOENT)
2466 ret = 1;
2467
2468 lock->lk->filename[i] = '.';
2469 }
2470 /* removing the loose one could have resurrected an earlier
2471 * packed one. Also, if it was not loose we need to repack
2472 * without it.
2473 */
2474 ret |= repack_without_ref(lock->ref_name);
2475
2476 unlink_or_warn(git_path("logs/%s", lock->ref_name));
2477 clear_loose_ref_cache(&ref_cache);
2478 unlock_ref(lock);
2479 return ret;
2480 }
2481
2482 /*
2483 * People using contrib's git-new-workdir have .git/logs/refs ->
2484 * /some/other/path/.git/logs/refs, and that may live on another device.
2485 *
2486 * IOW, to avoid cross device rename errors, the temporary renamed log must
2487 * live into logs/refs.
2488 */
2489 #define TMP_RENAMED_LOG "logs/refs/.tmp-renamed-log"
2490
2491 int rename_ref(const char *oldrefname, const char *newrefname, const char *logmsg)
2492 {
2493 unsigned char sha1[20], orig_sha1[20];
2494 int flag = 0, logmoved = 0;
2495 struct ref_lock *lock;
2496 struct stat loginfo;
2497 int log = !lstat(git_path("logs/%s", oldrefname), &loginfo);
2498 const char *symref = NULL;
2499
2500 if (log && S_ISLNK(loginfo.st_mode))
2501 return error("reflog for %s is a symlink", oldrefname);
2502
2503 symref = resolve_ref_unsafe(oldrefname, orig_sha1, 1, &flag);
2504 if (flag & REF_ISSYMREF)
2505 return error("refname %s is a symbolic ref, renaming it is not supported",
2506 oldrefname);
2507 if (!symref)
2508 return error("refname %s not found", oldrefname);
2509
2510 if (!is_refname_available(newrefname, oldrefname, get_packed_refs(&ref_cache)))
2511 return 1;
2512
2513 if (!is_refname_available(newrefname, oldrefname, get_loose_refs(&ref_cache)))
2514 return 1;
2515
2516 if (log && rename(git_path("logs/%s", oldrefname), git_path(TMP_RENAMED_LOG)))
2517 return error("unable to move logfile logs/%s to "TMP_RENAMED_LOG": %s",
2518 oldrefname, strerror(errno));
2519
2520 if (delete_ref(oldrefname, orig_sha1, REF_NODEREF)) {
2521 error("unable to delete old %s", oldrefname);
2522 goto rollback;
2523 }
2524
2525 if (!read_ref_full(newrefname, sha1, 1, &flag) &&
2526 delete_ref(newrefname, sha1, REF_NODEREF)) {
2527 if (errno==EISDIR) {
2528 if (remove_empty_directories(git_path("%s", newrefname))) {
2529 error("Directory not empty: %s", newrefname);
2530 goto rollback;
2531 }
2532 } else {
2533 error("unable to delete existing %s", newrefname);
2534 goto rollback;
2535 }
2536 }
2537
2538 if (log && safe_create_leading_directories(git_path("logs/%s", newrefname))) {
2539 error("unable to create directory for %s", newrefname);
2540 goto rollback;
2541 }
2542
2543 retry:
2544 if (log && rename(git_path(TMP_RENAMED_LOG), git_path("logs/%s", newrefname))) {
2545 if (errno==EISDIR || errno==ENOTDIR) {
2546 /*
2547 * rename(a, b) when b is an existing
2548 * directory ought to result in ISDIR, but
2549 * Solaris 5.8 gives ENOTDIR. Sheesh.
2550 */
2551 if (remove_empty_directories(git_path("logs/%s", newrefname))) {
2552 error("Directory not empty: logs/%s", newrefname);
2553 goto rollback;
2554 }
2555 goto retry;
2556 } else {
2557 error("unable to move logfile "TMP_RENAMED_LOG" to logs/%s: %s",
2558 newrefname, strerror(errno));
2559 goto rollback;
2560 }
2561 }
2562 logmoved = log;
2563
2564 lock = lock_ref_sha1_basic(newrefname, NULL, 0, NULL);
2565 if (!lock) {
2566 error("unable to lock %s for update", newrefname);
2567 goto rollback;
2568 }
2569 lock->force_write = 1;
2570 hashcpy(lock->old_sha1, orig_sha1);
2571 if (write_ref_sha1(lock, orig_sha1, logmsg)) {
2572 error("unable to write current sha1 into %s", newrefname);
2573 goto rollback;
2574 }
2575
2576 return 0;
2577
2578 rollback:
2579 lock = lock_ref_sha1_basic(oldrefname, NULL, 0, NULL);
2580 if (!lock) {
2581 error("unable to lock %s for rollback", oldrefname);
2582 goto rollbacklog;
2583 }
2584
2585 lock->force_write = 1;
2586 flag = log_all_ref_updates;
2587 log_all_ref_updates = 0;
2588 if (write_ref_sha1(lock, orig_sha1, NULL))
2589 error("unable to write current sha1 into %s", oldrefname);
2590 log_all_ref_updates = flag;
2591
2592 rollbacklog:
2593 if (logmoved && rename(git_path("logs/%s", newrefname), git_path("logs/%s", oldrefname)))
2594 error("unable to restore logfile %s from %s: %s",
2595 oldrefname, newrefname, strerror(errno));
2596 if (!logmoved && log &&
2597 rename(git_path(TMP_RENAMED_LOG), git_path("logs/%s", oldrefname)))
2598 error("unable to restore logfile %s from "TMP_RENAMED_LOG": %s",
2599 oldrefname, strerror(errno));
2600
2601 return 1;
2602 }
2603
2604 int close_ref(struct ref_lock *lock)
2605 {
2606 if (close_lock_file(lock->lk))
2607 return -1;
2608 lock->lock_fd = -1;
2609 return 0;
2610 }
2611
2612 int commit_ref(struct ref_lock *lock)
2613 {
2614 if (commit_lock_file(lock->lk))
2615 return -1;
2616 lock->lock_fd = -1;
2617 return 0;
2618 }
2619
2620 void unlock_ref(struct ref_lock *lock)
2621 {
2622 /* Do not free lock->lk -- atexit() still looks at them */
2623 if (lock->lk)
2624 rollback_lock_file(lock->lk);
2625 free(lock->ref_name);
2626 free(lock->orig_ref_name);
2627 free(lock);
2628 }
2629
2630 /*
2631 * copy the reflog message msg to buf, which has been allocated sufficiently
2632 * large, while cleaning up the whitespaces. Especially, convert LF to space,
2633 * because reflog file is one line per entry.
2634 */
2635 static int copy_msg(char *buf, const char *msg)
2636 {
2637 char *cp = buf;
2638 char c;
2639 int wasspace = 1;
2640
2641 *cp++ = '\t';
2642 while ((c = *msg++)) {
2643 if (wasspace && isspace(c))
2644 continue;
2645 wasspace = isspace(c);
2646 if (wasspace)
2647 c = ' ';
2648 *cp++ = c;
2649 }
2650 while (buf < cp && isspace(cp[-1]))
2651 cp--;
2652 *cp++ = '\n';
2653 return cp - buf;
2654 }
2655
2656 int log_ref_setup(const char *refname, char *logfile, int bufsize)
2657 {
2658 int logfd, oflags = O_APPEND | O_WRONLY;
2659
2660 git_snpath(logfile, bufsize, "logs/%s", refname);
2661 if (log_all_ref_updates &&
2662 (!prefixcmp(refname, "refs/heads/") ||
2663 !prefixcmp(refname, "refs/remotes/") ||
2664 !prefixcmp(refname, "refs/notes/") ||
2665 !strcmp(refname, "HEAD"))) {
2666 if (safe_create_leading_directories(logfile) < 0)
2667 return error("unable to create directory for %s",
2668 logfile);
2669 oflags |= O_CREAT;
2670 }
2671
2672 logfd = open(logfile, oflags, 0666);
2673 if (logfd < 0) {
2674 if (!(oflags & O_CREAT) && errno == ENOENT)
2675 return 0;
2676
2677 if ((oflags & O_CREAT) && errno == EISDIR) {
2678 if (remove_empty_directories(logfile)) {
2679 return error("There are still logs under '%s'",
2680 logfile);
2681 }
2682 logfd = open(logfile, oflags, 0666);
2683 }
2684
2685 if (logfd < 0)
2686 return error("Unable to append to %s: %s",
2687 logfile, strerror(errno));
2688 }
2689
2690 adjust_shared_perm(logfile);
2691 close(logfd);
2692 return 0;
2693 }
2694
2695 static int log_ref_write(const char *refname, const unsigned char *old_sha1,
2696 const unsigned char *new_sha1, const char *msg)
2697 {
2698 int logfd, result, written, oflags = O_APPEND | O_WRONLY;
2699 unsigned maxlen, len;
2700 int msglen;
2701 char log_file[PATH_MAX];
2702 char *logrec;
2703 const char *committer;
2704
2705 if (log_all_ref_updates < 0)
2706 log_all_ref_updates = !is_bare_repository();
2707
2708 result = log_ref_setup(refname, log_file, sizeof(log_file));
2709 if (result)
2710 return result;
2711
2712 logfd = open(log_file, oflags);
2713 if (logfd < 0)
2714 return 0;
2715 msglen = msg ? strlen(msg) : 0;
2716 committer = git_committer_info(0);
2717 maxlen = strlen(committer) + msglen + 100;
2718 logrec = xmalloc(maxlen);
2719 len = sprintf(logrec, "%s %s %s\n",
2720 sha1_to_hex(old_sha1),
2721 sha1_to_hex(new_sha1),
2722 committer);
2723 if (msglen)
2724 len += copy_msg(logrec + len - 1, msg) - 1;
2725 written = len <= maxlen ? write_in_full(logfd, logrec, len) : -1;
2726 free(logrec);
2727 if (close(logfd) != 0 || written != len)
2728 return error("Unable to append to %s", log_file);
2729 return 0;
2730 }
2731
2732 static int is_branch(const char *refname)
2733 {
2734 return !strcmp(refname, "HEAD") || !prefixcmp(refname, "refs/heads/");
2735 }
2736
2737 int write_ref_sha1(struct ref_lock *lock,
2738 const unsigned char *sha1, const char *logmsg)
2739 {
2740 static char term = '\n';
2741 struct object *o;
2742
2743 if (!lock)
2744 return -1;
2745 if (!lock->force_write && !hashcmp(lock->old_sha1, sha1)) {
2746 unlock_ref(lock);
2747 return 0;
2748 }
2749 o = parse_object(sha1);
2750 if (!o) {
2751 error("Trying to write ref %s with nonexistent object %s",
2752 lock->ref_name, sha1_to_hex(sha1));
2753 unlock_ref(lock);
2754 return -1;
2755 }
2756 if (o->type != OBJ_COMMIT && is_branch(lock->ref_name)) {
2757 error("Trying to write non-commit object %s to branch %s",
2758 sha1_to_hex(sha1), lock->ref_name);
2759 unlock_ref(lock);
2760 return -1;
2761 }
2762 if (write_in_full(lock->lock_fd, sha1_to_hex(sha1), 40) != 40 ||
2763 write_in_full(lock->lock_fd, &term, 1) != 1
2764 || close_ref(lock) < 0) {
2765 error("Couldn't write %s", lock->lk->filename);
2766 unlock_ref(lock);
2767 return -1;
2768 }
2769 clear_loose_ref_cache(&ref_cache);
2770 if (log_ref_write(lock->ref_name, lock->old_sha1, sha1, logmsg) < 0 ||
2771 (strcmp(lock->ref_name, lock->orig_ref_name) &&
2772 log_ref_write(lock->orig_ref_name, lock->old_sha1, sha1, logmsg) < 0)) {
2773 unlock_ref(lock);
2774 return -1;
2775 }
2776 if (strcmp(lock->orig_ref_name, "HEAD") != 0) {
2777 /*
2778 * Special hack: If a branch is updated directly and HEAD
2779 * points to it (may happen on the remote side of a push
2780 * for example) then logically the HEAD reflog should be
2781 * updated too.
2782 * A generic solution implies reverse symref information,
2783 * but finding all symrefs pointing to the given branch
2784 * would be rather costly for this rare event (the direct
2785 * update of a branch) to be worth it. So let's cheat and
2786 * check with HEAD only which should cover 99% of all usage
2787 * scenarios (even 100% of the default ones).
2788 */
2789 unsigned char head_sha1[20];
2790 int head_flag;
2791 const char *head_ref;
2792 head_ref = resolve_ref_unsafe("HEAD", head_sha1, 1, &head_flag);
2793 if (head_ref && (head_flag & REF_ISSYMREF) &&
2794 !strcmp(head_ref, lock->ref_name))
2795 log_ref_write("HEAD", lock->old_sha1, sha1, logmsg);
2796 }
2797 if (commit_ref(lock)) {
2798 error("Couldn't set %s", lock->ref_name);
2799 unlock_ref(lock);
2800 return -1;
2801 }
2802 unlock_ref(lock);
2803 return 0;
2804 }
2805
2806 int create_symref(const char *ref_target, const char *refs_heads_master,
2807 const char *logmsg)
2808 {
2809 const char *lockpath;
2810 char ref[1000];
2811 int fd, len, written;
2812 char *git_HEAD = git_pathdup("%s", ref_target);
2813 unsigned char old_sha1[20], new_sha1[20];
2814
2815 if (logmsg && read_ref(ref_target, old_sha1))
2816 hashclr(old_sha1);
2817
2818 if (safe_create_leading_directories(git_HEAD) < 0)
2819 return error("unable to create directory for %s", git_HEAD);
2820
2821 #ifndef NO_SYMLINK_HEAD
2822 if (prefer_symlink_refs) {
2823 unlink(git_HEAD);
2824 if (!symlink(refs_heads_master, git_HEAD))
2825 goto done;
2826 fprintf(stderr, "no symlink - falling back to symbolic ref\n");
2827 }
2828 #endif
2829
2830 len = snprintf(ref, sizeof(ref), "ref: %s\n", refs_heads_master);
2831 if (sizeof(ref) <= len) {
2832 error("refname too long: %s", refs_heads_master);
2833 goto error_free_return;
2834 }
2835 lockpath = mkpath("%s.lock", git_HEAD);
2836 fd = open(lockpath, O_CREAT | O_EXCL | O_WRONLY, 0666);
2837 if (fd < 0) {
2838 error("Unable to open %s for writing", lockpath);
2839 goto error_free_return;
2840 }
2841 written = write_in_full(fd, ref, len);
2842 if (close(fd) != 0 || written != len) {
2843 error("Unable to write to %s", lockpath);
2844 goto error_unlink_return;
2845 }
2846 if (rename(lockpath, git_HEAD) < 0) {
2847 error("Unable to create %s", git_HEAD);
2848 goto error_unlink_return;
2849 }
2850 if (adjust_shared_perm(git_HEAD)) {
2851 error("Unable to fix permissions on %s", lockpath);
2852 error_unlink_return:
2853 unlink_or_warn(lockpath);
2854 error_free_return:
2855 free(git_HEAD);
2856 return -1;
2857 }
2858
2859 #ifndef NO_SYMLINK_HEAD
2860 done:
2861 #endif
2862 if (logmsg && !read_ref(refs_heads_master, new_sha1))
2863 log_ref_write(ref_target, old_sha1, new_sha1, logmsg);
2864
2865 free(git_HEAD);
2866 return 0;
2867 }
2868
2869 static char *ref_msg(const char *line, const char *endp)
2870 {
2871 const char *ep;
2872 line += 82;
2873 ep = memchr(line, '\n', endp - line);
2874 if (!ep)
2875 ep = endp;
2876 return xmemdupz(line, ep - line);
2877 }
2878
2879 int read_ref_at(const char *refname, unsigned long at_time, int cnt,
2880 unsigned char *sha1, char **msg,
2881 unsigned long *cutoff_time, int *cutoff_tz, int *cutoff_cnt)
2882 {
2883 const char *logfile, *logdata, *logend, *rec, *lastgt, *lastrec;
2884 char *tz_c;
2885 int logfd, tz, reccnt = 0;
2886 struct stat st;
2887 unsigned long date;
2888 unsigned char logged_sha1[20];
2889 void *log_mapped;
2890 size_t mapsz;
2891
2892 logfile = git_path("logs/%s", refname);
2893 logfd = open(logfile, O_RDONLY, 0);
2894 if (logfd < 0)
2895 die_errno("Unable to read log '%s'", logfile);
2896 fstat(logfd, &st);
2897 if (!st.st_size)
2898 die("Log %s is empty.", logfile);
2899 mapsz = xsize_t(st.st_size);
2900 log_mapped = xmmap(NULL, mapsz, PROT_READ, MAP_PRIVATE, logfd, 0);
2901 logdata = log_mapped;
2902 close(logfd);
2903
2904 lastrec = NULL;
2905 rec = logend = logdata + st.st_size;
2906 while (logdata < rec) {
2907 reccnt++;
2908 if (logdata < rec && *(rec-1) == '\n')
2909 rec--;
2910 lastgt = NULL;
2911 while (logdata < rec && *(rec-1) != '\n') {
2912 rec--;
2913 if (*rec == '>')
2914 lastgt = rec;
2915 }
2916 if (!lastgt)
2917 die("Log %s is corrupt.", logfile);
2918 date = strtoul(lastgt + 1, &tz_c, 10);
2919 if (date <= at_time || cnt == 0) {
2920 tz = strtoul(tz_c, NULL, 10);
2921 if (msg)
2922 *msg = ref_msg(rec, logend);
2923 if (cutoff_time)
2924 *cutoff_time = date;
2925 if (cutoff_tz)
2926 *cutoff_tz = tz;
2927 if (cutoff_cnt)
2928 *cutoff_cnt = reccnt - 1;
2929 if (lastrec) {
2930 if (get_sha1_hex(lastrec, logged_sha1))
2931 die("Log %s is corrupt.", logfile);
2932 if (get_sha1_hex(rec + 41, sha1))
2933 die("Log %s is corrupt.", logfile);
2934 if (hashcmp(logged_sha1, sha1)) {
2935 warning("Log %s has gap after %s.",
2936 logfile, show_date(date, tz, DATE_RFC2822));
2937 }
2938 }
2939 else if (date == at_time) {
2940 if (get_sha1_hex(rec + 41, sha1))
2941 die("Log %s is corrupt.", logfile);
2942 }
2943 else {
2944 if (get_sha1_hex(rec + 41, logged_sha1))
2945 die("Log %s is corrupt.", logfile);
2946 if (hashcmp(logged_sha1, sha1)) {
2947 warning("Log %s unexpectedly ended on %s.",
2948 logfile, show_date(date, tz, DATE_RFC2822));
2949 }
2950 }
2951 munmap(log_mapped, mapsz);
2952 return 0;
2953 }
2954 lastrec = rec;
2955 if (cnt > 0)
2956 cnt--;
2957 }
2958
2959 rec = logdata;
2960 while (rec < logend && *rec != '>' && *rec != '\n')
2961 rec++;
2962 if (rec == logend || *rec == '\n')
2963 die("Log %s is corrupt.", logfile);
2964 date = strtoul(rec + 1, &tz_c, 10);
2965 tz = strtoul(tz_c, NULL, 10);
2966 if (get_sha1_hex(logdata, sha1))
2967 die("Log %s is corrupt.", logfile);
2968 if (is_null_sha1(sha1)) {
2969 if (get_sha1_hex(logdata + 41, sha1))
2970 die("Log %s is corrupt.", logfile);
2971 }
2972 if (msg)
2973 *msg = ref_msg(logdata, logend);
2974 munmap(log_mapped, mapsz);
2975
2976 if (cutoff_time)
2977 *cutoff_time = date;
2978 if (cutoff_tz)
2979 *cutoff_tz = tz;
2980 if (cutoff_cnt)
2981 *cutoff_cnt = reccnt;
2982 return 1;
2983 }
2984
2985 static int show_one_reflog_ent(struct strbuf *sb, each_reflog_ent_fn fn, void *cb_data)
2986 {
2987 unsigned char osha1[20], nsha1[20];
2988 char *email_end, *message;
2989 unsigned long timestamp;
2990 int tz;
2991
2992 /* old SP new SP name <email> SP time TAB msg LF */
2993 if (sb->len < 83 || sb->buf[sb->len - 1] != '\n' ||
2994 get_sha1_hex(sb->buf, osha1) || sb->buf[40] != ' ' ||
2995 get_sha1_hex(sb->buf + 41, nsha1) || sb->buf[81] != ' ' ||
2996 !(email_end = strchr(sb->buf + 82, '>')) ||
2997 email_end[1] != ' ' ||
2998 !(timestamp = strtoul(email_end + 2, &message, 10)) ||
2999 !message || message[0] != ' ' ||
3000 (message[1] != '+' && message[1] != '-') ||
3001 !isdigit(message[2]) || !isdigit(message[3]) ||
3002 !isdigit(message[4]) || !isdigit(message[5]))
3003 return 0; /* corrupt? */
3004 email_end[1] = '\0';
3005 tz = strtol(message + 1, NULL, 10);
3006 if (message[6] != '\t')
3007 message += 6;
3008 else
3009 message += 7;
3010 return fn(osha1, nsha1, sb->buf + 82, timestamp, tz, message, cb_data);
3011 }
3012
3013 static char *find_beginning_of_line(char *bob, char *scan)
3014 {
3015 while (bob < scan && *(--scan) != '\n')
3016 ; /* keep scanning backwards */
3017 /*
3018 * Return either beginning of the buffer, or LF at the end of
3019 * the previous line.
3020 */
3021 return scan;
3022 }
3023
3024 int for_each_reflog_ent_reverse(const char *refname, each_reflog_ent_fn fn, void *cb_data)
3025 {
3026 struct strbuf sb = STRBUF_INIT;
3027 FILE *logfp;
3028 long pos;
3029 int ret = 0, at_tail = 1;
3030
3031 logfp = fopen(git_path("logs/%s", refname), "r");
3032 if (!logfp)
3033 return -1;
3034
3035 /* Jump to the end */
3036 if (fseek(logfp, 0, SEEK_END) < 0)
3037 return error("cannot seek back reflog for %s: %s",
3038 refname, strerror(errno));
3039 pos = ftell(logfp);
3040 while (!ret && 0 < pos) {
3041 int cnt;
3042 size_t nread;
3043 char buf[BUFSIZ];
3044 char *endp, *scanp;
3045
3046 /* Fill next block from the end */
3047 cnt = (sizeof(buf) < pos) ? sizeof(buf) : pos;
3048 if (fseek(logfp, pos - cnt, SEEK_SET))
3049 return error("cannot seek back reflog for %s: %s",
3050 refname, strerror(errno));
3051 nread = fread(buf, cnt, 1, logfp);
3052 if (nread != 1)
3053 return error("cannot read %d bytes from reflog for %s: %s",
3054 cnt, refname, strerror(errno));
3055 pos -= cnt;
3056
3057 scanp = endp = buf + cnt;
3058 if (at_tail && scanp[-1] == '\n')
3059 /* Looking at the final LF at the end of the file */
3060 scanp--;
3061 at_tail = 0;
3062
3063 while (buf < scanp) {
3064 /*
3065 * terminating LF of the previous line, or the beginning
3066 * of the buffer.
3067 */
3068 char *bp;
3069
3070 bp = find_beginning_of_line(buf, scanp);
3071
3072 if (*bp != '\n') {
3073 strbuf_splice(&sb, 0, 0, buf, endp - buf);
3074 if (pos)
3075 break; /* need to fill another block */
3076 scanp = buf - 1; /* leave loop */
3077 } else {
3078 /*
3079 * (bp + 1) thru endp is the beginning of the
3080 * current line we have in sb
3081 */
3082 strbuf_splice(&sb, 0, 0, bp + 1, endp - (bp + 1));
3083 scanp = bp;
3084 endp = bp + 1;
3085 }
3086 ret = show_one_reflog_ent(&sb, fn, cb_data);
3087 strbuf_reset(&sb);
3088 if (ret)
3089 break;
3090 }
3091
3092 }
3093 if (!ret && sb.len)
3094 ret = show_one_reflog_ent(&sb, fn, cb_data);
3095
3096 fclose(logfp);
3097 strbuf_release(&sb);
3098 return ret;
3099 }
3100
3101 int for_each_reflog_ent(const char *refname, each_reflog_ent_fn fn, void *cb_data)
3102 {
3103 FILE *logfp;
3104 struct strbuf sb = STRBUF_INIT;
3105 int ret = 0;
3106
3107 logfp = fopen(git_path("logs/%s", refname), "r");
3108 if (!logfp)
3109 return -1;
3110
3111 while (!ret && !strbuf_getwholeline(&sb, logfp, '\n'))
3112 ret = show_one_reflog_ent(&sb, fn, cb_data);
3113 fclose(logfp);
3114 strbuf_release(&sb);
3115 return ret;
3116 }
3117 /*
3118 * Call fn for each reflog in the namespace indicated by name. name
3119 * must be empty or end with '/'. Name will be used as a scratch
3120 * space, but its contents will be restored before return.
3121 */
3122 static int do_for_each_reflog(struct strbuf *name, each_ref_fn fn, void *cb_data)
3123 {
3124 DIR *d = opendir(git_path("logs/%s", name->buf));
3125 int retval = 0;
3126 struct dirent *de;
3127 int oldlen = name->len;
3128
3129 if (!d)
3130 return name->len ? errno : 0;
3131
3132 while ((de = readdir(d)) != NULL) {
3133 struct stat st;
3134
3135 if (de->d_name[0] == '.')
3136 continue;
3137 if (has_extension(de->d_name, ".lock"))
3138 continue;
3139 strbuf_addstr(name, de->d_name);
3140 if (stat(git_path("logs/%s", name->buf), &st) < 0) {
3141 ; /* silently ignore */
3142 } else {
3143 if (S_ISDIR(st.st_mode)) {
3144 strbuf_addch(name, '/');
3145 retval = do_for_each_reflog(name, fn, cb_data);
3146 } else {
3147 unsigned char sha1[20];
3148 if (read_ref_full(name->buf, sha1, 0, NULL))
3149 retval = error("bad ref for %s", name->buf);
3150 else
3151 retval = fn(name->buf, sha1, 0, cb_data);
3152 }
3153 if (retval)
3154 break;
3155 }
3156 strbuf_setlen(name, oldlen);
3157 }
3158 closedir(d);
3159 return retval;
3160 }
3161
3162 int for_each_reflog(each_ref_fn fn, void *cb_data)
3163 {
3164 int retval;
3165 struct strbuf name;
3166 strbuf_init(&name, PATH_MAX);
3167 retval = do_for_each_reflog(&name, fn, cb_data);
3168 strbuf_release(&name);
3169 return retval;
3170 }
3171
3172 int update_ref(const char *action, const char *refname,
3173 const unsigned char *sha1, const unsigned char *oldval,
3174 int flags, enum action_on_err onerr)
3175 {
3176 static struct ref_lock *lock;
3177 lock = lock_any_ref_for_update(refname, oldval, flags);
3178 if (!lock) {
3179 const char *str = "Cannot lock the ref '%s'.";
3180 switch (onerr) {
3181 case MSG_ON_ERR: error(str, refname); break;
3182 case DIE_ON_ERR: die(str, refname); break;
3183 case QUIET_ON_ERR: break;
3184 }
3185 return 1;
3186 }
3187 if (write_ref_sha1(lock, sha1, action) < 0) {
3188 const char *str = "Cannot update the ref '%s'.";
3189 switch (onerr) {
3190 case MSG_ON_ERR: error(str, refname); break;
3191 case DIE_ON_ERR: die(str, refname); break;
3192 case QUIET_ON_ERR: break;
3193 }
3194 return 1;
3195 }
3196 return 0;
3197 }
3198
3199 struct ref *find_ref_by_name(const struct ref *list, const char *name)
3200 {
3201 for ( ; list; list = list->next)
3202 if (!strcmp(list->name, name))
3203 return (struct ref *)list;
3204 return NULL;
3205 }
3206
3207 /*
3208 * generate a format suitable for scanf from a ref_rev_parse_rules
3209 * rule, that is replace the "%.*s" spec with a "%s" spec
3210 */
3211 static void gen_scanf_fmt(char *scanf_fmt, const char *rule)
3212 {
3213 char *spec;
3214
3215 spec = strstr(rule, "%.*s");
3216 if (!spec || strstr(spec + 4, "%.*s"))
3217 die("invalid rule in ref_rev_parse_rules: %s", rule);
3218
3219 /* copy all until spec */
3220 strncpy(scanf_fmt, rule, spec - rule);
3221 scanf_fmt[spec - rule] = '\0';
3222 /* copy new spec */
3223 strcat(scanf_fmt, "%s");
3224 /* copy remaining rule */
3225 strcat(scanf_fmt, spec + 4);
3226
3227 return;
3228 }
3229
3230 char *shorten_unambiguous_ref(const char *refname, int strict)
3231 {
3232 int i;
3233 static char **scanf_fmts;
3234 static int nr_rules;
3235 char *short_name;
3236
3237 /* pre generate scanf formats from ref_rev_parse_rules[] */
3238 if (!nr_rules) {
3239 size_t total_len = 0;
3240
3241 /* the rule list is NULL terminated, count them first */
3242 for (; ref_rev_parse_rules[nr_rules]; nr_rules++)
3243 /* no +1 because strlen("%s") < strlen("%.*s") */
3244 total_len += strlen(ref_rev_parse_rules[nr_rules]);
3245
3246 scanf_fmts = xmalloc(nr_rules * sizeof(char *) + total_len);
3247
3248 total_len = 0;
3249 for (i = 0; i < nr_rules; i++) {
3250 scanf_fmts[i] = (char *)&scanf_fmts[nr_rules]
3251 + total_len;
3252 gen_scanf_fmt(scanf_fmts[i], ref_rev_parse_rules[i]);
3253 total_len += strlen(ref_rev_parse_rules[i]);
3254 }
3255 }
3256
3257 /* bail out if there are no rules */
3258 if (!nr_rules)
3259 return xstrdup(refname);
3260
3261 /* buffer for scanf result, at most refname must fit */
3262 short_name = xstrdup(refname);
3263
3264 /* skip first rule, it will always match */
3265 for (i = nr_rules - 1; i > 0 ; --i) {
3266 int j;
3267 int rules_to_fail = i;
3268 int short_name_len;
3269
3270 if (1 != sscanf(refname, scanf_fmts[i], short_name))
3271 continue;
3272
3273 short_name_len = strlen(short_name);
3274
3275 /*
3276 * in strict mode, all (except the matched one) rules
3277 * must fail to resolve to a valid non-ambiguous ref
3278 */
3279 if (strict)
3280 rules_to_fail = nr_rules;
3281
3282 /*
3283 * check if the short name resolves to a valid ref,
3284 * but use only rules prior to the matched one
3285 */
3286 for (j = 0; j < rules_to_fail; j++) {
3287 const char *rule = ref_rev_parse_rules[j];
3288 char refname[PATH_MAX];
3289
3290 /* skip matched rule */
3291 if (i == j)
3292 continue;
3293
3294 /*
3295 * the short name is ambiguous, if it resolves
3296 * (with this previous rule) to a valid ref
3297 * read_ref() returns 0 on success
3298 */
3299 mksnpath(refname, sizeof(refname),
3300 rule, short_name_len, short_name);
3301 if (ref_exists(refname))
3302 break;
3303 }
3304
3305 /*
3306 * short name is non-ambiguous if all previous rules
3307 * haven't resolved to a valid ref
3308 */
3309 if (j == rules_to_fail)
3310 return short_name;
3311 }
3312
3313 free(short_name);
3314 return xstrdup(refname);
3315 }
3316
3317 static struct string_list *hide_refs;
3318
3319 int parse_hide_refs_config(const char *var, const char *value, const char *section)
3320 {
3321 if (!strcmp("transfer.hiderefs", var) ||
3322 /* NEEDSWORK: use parse_config_key() once both are merged */
3323 (!prefixcmp(var, section) && var[strlen(section)] == '.' &&
3324 !strcmp(var + strlen(section), ".hiderefs"))) {
3325 char *ref;
3326 int len;
3327
3328 if (!value)
3329 return config_error_nonbool(var);
3330 ref = xstrdup(value);
3331 len = strlen(ref);
3332 while (len && ref[len - 1] == '/')
3333 ref[--len] = '\0';
3334 if (!hide_refs) {
3335 hide_refs = xcalloc(1, sizeof(*hide_refs));
3336 hide_refs->strdup_strings = 1;
3337 }
3338 string_list_append(hide_refs, ref);
3339 }
3340 return 0;
3341 }
3342
3343 int ref_is_hidden(const char *refname)
3344 {
3345 struct string_list_item *item;
3346
3347 if (!hide_refs)
3348 return 0;
3349 for_each_string_list_item(item, hide_refs) {
3350 int len;
3351 if (prefixcmp(refname, item->string))
3352 continue;
3353 len = strlen(item->string);
3354 if (!refname[len] || refname[len] == '/')
3355 return 1;
3356 }
3357 return 0;
3358 }