refs: add ref_type function
[git/git.git] / refs.c
1 #include "cache.h"
2 #include "lockfile.h"
3 #include "refs.h"
4 #include "object.h"
5 #include "tag.h"
6 #include "dir.h"
7 #include "string-list.h"
8
9 struct ref_lock {
10 char *ref_name;
11 char *orig_ref_name;
12 struct lock_file *lk;
13 struct object_id old_oid;
14 };
15
16 /*
17 * How to handle various characters in refnames:
18 * 0: An acceptable character for refs
19 * 1: End-of-component
20 * 2: ., look for a preceding . to reject .. in refs
21 * 3: {, look for a preceding @ to reject @{ in refs
22 * 4: A bad character: ASCII control characters, "~", "^", ":" or SP
23 */
24 static unsigned char refname_disposition[256] = {
25 1, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
26 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
27 4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4, 0, 0, 0, 2, 1,
28 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4, 0, 0, 0, 0, 4,
29 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
30 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4, 4, 0, 4, 0,
31 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
32 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 3, 0, 0, 4, 4
33 };
34
35 /*
36 * Flag passed to lock_ref_sha1_basic() telling it to tolerate broken
37 * refs (i.e., because the reference is about to be deleted anyway).
38 */
39 #define REF_DELETING 0x02
40
41 /*
42 * Used as a flag in ref_update::flags when a loose ref is being
43 * pruned.
44 */
45 #define REF_ISPRUNING 0x04
46
47 /*
48 * Used as a flag in ref_update::flags when the reference should be
49 * updated to new_sha1.
50 */
51 #define REF_HAVE_NEW 0x08
52
53 /*
54 * Used as a flag in ref_update::flags when old_sha1 should be
55 * checked.
56 */
57 #define REF_HAVE_OLD 0x10
58
59 /*
60 * Used as a flag in ref_update::flags when the lockfile needs to be
61 * committed.
62 */
63 #define REF_NEEDS_COMMIT 0x20
64
65 /*
66 * 0x40 is REF_FORCE_CREATE_REFLOG, so skip it if you're adding a
67 * value to ref_update::flags
68 */
69
70 /*
71 * Try to read one refname component from the front of refname.
72 * Return the length of the component found, or -1 if the component is
73 * not legal. It is legal if it is something reasonable to have under
74 * ".git/refs/"; We do not like it if:
75 *
76 * - any path component of it begins with ".", or
77 * - it has double dots "..", or
78 * - it has ASCII control character, "~", "^", ":" or SP, anywhere, or
79 * - it ends with a "/".
80 * - it ends with ".lock"
81 * - it contains a "\" (backslash)
82 */
83 static int check_refname_component(const char *refname, int flags)
84 {
85 const char *cp;
86 char last = '\0';
87
88 for (cp = refname; ; cp++) {
89 int ch = *cp & 255;
90 unsigned char disp = refname_disposition[ch];
91 switch (disp) {
92 case 1:
93 goto out;
94 case 2:
95 if (last == '.')
96 return -1; /* Refname contains "..". */
97 break;
98 case 3:
99 if (last == '@')
100 return -1; /* Refname contains "@{". */
101 break;
102 case 4:
103 return -1;
104 }
105 last = ch;
106 }
107 out:
108 if (cp == refname)
109 return 0; /* Component has zero length. */
110 if (refname[0] == '.')
111 return -1; /* Component starts with '.'. */
112 if (cp - refname >= LOCK_SUFFIX_LEN &&
113 !memcmp(cp - LOCK_SUFFIX_LEN, LOCK_SUFFIX, LOCK_SUFFIX_LEN))
114 return -1; /* Refname ends with ".lock". */
115 return cp - refname;
116 }
117
118 int check_refname_format(const char *refname, int flags)
119 {
120 int component_len, component_count = 0;
121
122 if (!strcmp(refname, "@"))
123 /* Refname is a single character '@'. */
124 return -1;
125
126 while (1) {
127 /* We are at the start of a path component. */
128 component_len = check_refname_component(refname, flags);
129 if (component_len <= 0) {
130 if ((flags & REFNAME_REFSPEC_PATTERN) &&
131 refname[0] == '*' &&
132 (refname[1] == '\0' || refname[1] == '/')) {
133 /* Accept one wildcard as a full refname component. */
134 flags &= ~REFNAME_REFSPEC_PATTERN;
135 component_len = 1;
136 } else {
137 return -1;
138 }
139 }
140 component_count++;
141 if (refname[component_len] == '\0')
142 break;
143 /* Skip to next component. */
144 refname += component_len + 1;
145 }
146
147 if (refname[component_len - 1] == '.')
148 return -1; /* Refname ends with '.'. */
149 if (!(flags & REFNAME_ALLOW_ONELEVEL) && component_count < 2)
150 return -1; /* Refname has only one component. */
151 return 0;
152 }
153
154 struct ref_entry;
155
156 /*
157 * Information used (along with the information in ref_entry) to
158 * describe a single cached reference. This data structure only
159 * occurs embedded in a union in struct ref_entry, and only when
160 * (ref_entry->flag & REF_DIR) is zero.
161 */
162 struct ref_value {
163 /*
164 * The name of the object to which this reference resolves
165 * (which may be a tag object). If REF_ISBROKEN, this is
166 * null. If REF_ISSYMREF, then this is the name of the object
167 * referred to by the last reference in the symlink chain.
168 */
169 struct object_id oid;
170
171 /*
172 * If REF_KNOWS_PEELED, then this field holds the peeled value
173 * of this reference, or null if the reference is known not to
174 * be peelable. See the documentation for peel_ref() for an
175 * exact definition of "peelable".
176 */
177 struct object_id peeled;
178 };
179
180 struct ref_cache;
181
182 /*
183 * Information used (along with the information in ref_entry) to
184 * describe a level in the hierarchy of references. This data
185 * structure only occurs embedded in a union in struct ref_entry, and
186 * only when (ref_entry.flag & REF_DIR) is set. In that case,
187 * (ref_entry.flag & REF_INCOMPLETE) determines whether the references
188 * in the directory have already been read:
189 *
190 * (ref_entry.flag & REF_INCOMPLETE) unset -- a directory of loose
191 * or packed references, already read.
192 *
193 * (ref_entry.flag & REF_INCOMPLETE) set -- a directory of loose
194 * references that hasn't been read yet (nor has any of its
195 * subdirectories).
196 *
197 * Entries within a directory are stored within a growable array of
198 * pointers to ref_entries (entries, nr, alloc). Entries 0 <= i <
199 * sorted are sorted by their component name in strcmp() order and the
200 * remaining entries are unsorted.
201 *
202 * Loose references are read lazily, one directory at a time. When a
203 * directory of loose references is read, then all of the references
204 * in that directory are stored, and REF_INCOMPLETE stubs are created
205 * for any subdirectories, but the subdirectories themselves are not
206 * read. The reading is triggered by get_ref_dir().
207 */
208 struct ref_dir {
209 int nr, alloc;
210
211 /*
212 * Entries with index 0 <= i < sorted are sorted by name. New
213 * entries are appended to the list unsorted, and are sorted
214 * only when required; thus we avoid the need to sort the list
215 * after the addition of every reference.
216 */
217 int sorted;
218
219 /* A pointer to the ref_cache that contains this ref_dir. */
220 struct ref_cache *ref_cache;
221
222 struct ref_entry **entries;
223 };
224
225 /*
226 * Bit values for ref_entry::flag. REF_ISSYMREF=0x01,
227 * REF_ISPACKED=0x02, REF_ISBROKEN=0x04 and REF_BAD_NAME=0x08 are
228 * public values; see refs.h.
229 */
230
231 /*
232 * The field ref_entry->u.value.peeled of this value entry contains
233 * the correct peeled value for the reference, which might be
234 * null_sha1 if the reference is not a tag or if it is broken.
235 */
236 #define REF_KNOWS_PEELED 0x10
237
238 /* ref_entry represents a directory of references */
239 #define REF_DIR 0x20
240
241 /*
242 * Entry has not yet been read from disk (used only for REF_DIR
243 * entries representing loose references)
244 */
245 #define REF_INCOMPLETE 0x40
246
247 /*
248 * A ref_entry represents either a reference or a "subdirectory" of
249 * references.
250 *
251 * Each directory in the reference namespace is represented by a
252 * ref_entry with (flags & REF_DIR) set and containing a subdir member
253 * that holds the entries in that directory that have been read so
254 * far. If (flags & REF_INCOMPLETE) is set, then the directory and
255 * its subdirectories haven't been read yet. REF_INCOMPLETE is only
256 * used for loose reference directories.
257 *
258 * References are represented by a ref_entry with (flags & REF_DIR)
259 * unset and a value member that describes the reference's value. The
260 * flag member is at the ref_entry level, but it is also needed to
261 * interpret the contents of the value field (in other words, a
262 * ref_value object is not very much use without the enclosing
263 * ref_entry).
264 *
265 * Reference names cannot end with slash and directories' names are
266 * always stored with a trailing slash (except for the top-level
267 * directory, which is always denoted by ""). This has two nice
268 * consequences: (1) when the entries in each subdir are sorted
269 * lexicographically by name (as they usually are), the references in
270 * a whole tree can be generated in lexicographic order by traversing
271 * the tree in left-to-right, depth-first order; (2) the names of
272 * references and subdirectories cannot conflict, and therefore the
273 * presence of an empty subdirectory does not block the creation of a
274 * similarly-named reference. (The fact that reference names with the
275 * same leading components can conflict *with each other* is a
276 * separate issue that is regulated by verify_refname_available().)
277 *
278 * Please note that the name field contains the fully-qualified
279 * reference (or subdirectory) name. Space could be saved by only
280 * storing the relative names. But that would require the full names
281 * to be generated on the fly when iterating in do_for_each_ref(), and
282 * would break callback functions, who have always been able to assume
283 * that the name strings that they are passed will not be freed during
284 * the iteration.
285 */
286 struct ref_entry {
287 unsigned char flag; /* ISSYMREF? ISPACKED? */
288 union {
289 struct ref_value value; /* if not (flags&REF_DIR) */
290 struct ref_dir subdir; /* if (flags&REF_DIR) */
291 } u;
292 /*
293 * The full name of the reference (e.g., "refs/heads/master")
294 * or the full name of the directory with a trailing slash
295 * (e.g., "refs/heads/"):
296 */
297 char name[FLEX_ARRAY];
298 };
299
300 static void read_loose_refs(const char *dirname, struct ref_dir *dir);
301
302 static struct ref_dir *get_ref_dir(struct ref_entry *entry)
303 {
304 struct ref_dir *dir;
305 assert(entry->flag & REF_DIR);
306 dir = &entry->u.subdir;
307 if (entry->flag & REF_INCOMPLETE) {
308 read_loose_refs(entry->name, dir);
309 entry->flag &= ~REF_INCOMPLETE;
310 }
311 return dir;
312 }
313
314 /*
315 * Check if a refname is safe.
316 * For refs that start with "refs/" we consider it safe as long they do
317 * not try to resolve to outside of refs/.
318 *
319 * For all other refs we only consider them safe iff they only contain
320 * upper case characters and '_' (like "HEAD" AND "MERGE_HEAD", and not like
321 * "config").
322 */
323 static int refname_is_safe(const char *refname)
324 {
325 if (starts_with(refname, "refs/")) {
326 char *buf;
327 int result;
328
329 buf = xmalloc(strlen(refname) + 1);
330 /*
331 * Does the refname try to escape refs/?
332 * For example: refs/foo/../bar is safe but refs/foo/../../bar
333 * is not.
334 */
335 result = !normalize_path_copy(buf, refname + strlen("refs/"));
336 free(buf);
337 return result;
338 }
339 while (*refname) {
340 if (!isupper(*refname) && *refname != '_')
341 return 0;
342 refname++;
343 }
344 return 1;
345 }
346
347 static struct ref_entry *create_ref_entry(const char *refname,
348 const unsigned char *sha1, int flag,
349 int check_name)
350 {
351 int len;
352 struct ref_entry *ref;
353
354 if (check_name &&
355 check_refname_format(refname, REFNAME_ALLOW_ONELEVEL))
356 die("Reference has invalid format: '%s'", refname);
357 len = strlen(refname) + 1;
358 ref = xmalloc(sizeof(struct ref_entry) + len);
359 hashcpy(ref->u.value.oid.hash, sha1);
360 oidclr(&ref->u.value.peeled);
361 memcpy(ref->name, refname, len);
362 ref->flag = flag;
363 return ref;
364 }
365
366 static void clear_ref_dir(struct ref_dir *dir);
367
368 static void free_ref_entry(struct ref_entry *entry)
369 {
370 if (entry->flag & REF_DIR) {
371 /*
372 * Do not use get_ref_dir() here, as that might
373 * trigger the reading of loose refs.
374 */
375 clear_ref_dir(&entry->u.subdir);
376 }
377 free(entry);
378 }
379
380 /*
381 * Add a ref_entry to the end of dir (unsorted). Entry is always
382 * stored directly in dir; no recursion into subdirectories is
383 * done.
384 */
385 static void add_entry_to_dir(struct ref_dir *dir, struct ref_entry *entry)
386 {
387 ALLOC_GROW(dir->entries, dir->nr + 1, dir->alloc);
388 dir->entries[dir->nr++] = entry;
389 /* optimize for the case that entries are added in order */
390 if (dir->nr == 1 ||
391 (dir->nr == dir->sorted + 1 &&
392 strcmp(dir->entries[dir->nr - 2]->name,
393 dir->entries[dir->nr - 1]->name) < 0))
394 dir->sorted = dir->nr;
395 }
396
397 /*
398 * Clear and free all entries in dir, recursively.
399 */
400 static void clear_ref_dir(struct ref_dir *dir)
401 {
402 int i;
403 for (i = 0; i < dir->nr; i++)
404 free_ref_entry(dir->entries[i]);
405 free(dir->entries);
406 dir->sorted = dir->nr = dir->alloc = 0;
407 dir->entries = NULL;
408 }
409
410 /*
411 * Create a struct ref_entry object for the specified dirname.
412 * dirname is the name of the directory with a trailing slash (e.g.,
413 * "refs/heads/") or "" for the top-level directory.
414 */
415 static struct ref_entry *create_dir_entry(struct ref_cache *ref_cache,
416 const char *dirname, size_t len,
417 int incomplete)
418 {
419 struct ref_entry *direntry;
420 direntry = xcalloc(1, sizeof(struct ref_entry) + len + 1);
421 memcpy(direntry->name, dirname, len);
422 direntry->name[len] = '\0';
423 direntry->u.subdir.ref_cache = ref_cache;
424 direntry->flag = REF_DIR | (incomplete ? REF_INCOMPLETE : 0);
425 return direntry;
426 }
427
428 static int ref_entry_cmp(const void *a, const void *b)
429 {
430 struct ref_entry *one = *(struct ref_entry **)a;
431 struct ref_entry *two = *(struct ref_entry **)b;
432 return strcmp(one->name, two->name);
433 }
434
435 static void sort_ref_dir(struct ref_dir *dir);
436
437 struct string_slice {
438 size_t len;
439 const char *str;
440 };
441
442 static int ref_entry_cmp_sslice(const void *key_, const void *ent_)
443 {
444 const struct string_slice *key = key_;
445 const struct ref_entry *ent = *(const struct ref_entry * const *)ent_;
446 int cmp = strncmp(key->str, ent->name, key->len);
447 if (cmp)
448 return cmp;
449 return '\0' - (unsigned char)ent->name[key->len];
450 }
451
452 /*
453 * Return the index of the entry with the given refname from the
454 * ref_dir (non-recursively), sorting dir if necessary. Return -1 if
455 * no such entry is found. dir must already be complete.
456 */
457 static int search_ref_dir(struct ref_dir *dir, const char *refname, size_t len)
458 {
459 struct ref_entry **r;
460 struct string_slice key;
461
462 if (refname == NULL || !dir->nr)
463 return -1;
464
465 sort_ref_dir(dir);
466 key.len = len;
467 key.str = refname;
468 r = bsearch(&key, dir->entries, dir->nr, sizeof(*dir->entries),
469 ref_entry_cmp_sslice);
470
471 if (r == NULL)
472 return -1;
473
474 return r - dir->entries;
475 }
476
477 /*
478 * Search for a directory entry directly within dir (without
479 * recursing). Sort dir if necessary. subdirname must be a directory
480 * name (i.e., end in '/'). If mkdir is set, then create the
481 * directory if it is missing; otherwise, return NULL if the desired
482 * directory cannot be found. dir must already be complete.
483 */
484 static struct ref_dir *search_for_subdir(struct ref_dir *dir,
485 const char *subdirname, size_t len,
486 int mkdir)
487 {
488 int entry_index = search_ref_dir(dir, subdirname, len);
489 struct ref_entry *entry;
490 if (entry_index == -1) {
491 if (!mkdir)
492 return NULL;
493 /*
494 * Since dir is complete, the absence of a subdir
495 * means that the subdir really doesn't exist;
496 * therefore, create an empty record for it but mark
497 * the record complete.
498 */
499 entry = create_dir_entry(dir->ref_cache, subdirname, len, 0);
500 add_entry_to_dir(dir, entry);
501 } else {
502 entry = dir->entries[entry_index];
503 }
504 return get_ref_dir(entry);
505 }
506
507 /*
508 * If refname is a reference name, find the ref_dir within the dir
509 * tree that should hold refname. If refname is a directory name
510 * (i.e., ends in '/'), then return that ref_dir itself. dir must
511 * represent the top-level directory and must already be complete.
512 * Sort ref_dirs and recurse into subdirectories as necessary. If
513 * mkdir is set, then create any missing directories; otherwise,
514 * return NULL if the desired directory cannot be found.
515 */
516 static struct ref_dir *find_containing_dir(struct ref_dir *dir,
517 const char *refname, int mkdir)
518 {
519 const char *slash;
520 for (slash = strchr(refname, '/'); slash; slash = strchr(slash + 1, '/')) {
521 size_t dirnamelen = slash - refname + 1;
522 struct ref_dir *subdir;
523 subdir = search_for_subdir(dir, refname, dirnamelen, mkdir);
524 if (!subdir) {
525 dir = NULL;
526 break;
527 }
528 dir = subdir;
529 }
530
531 return dir;
532 }
533
534 /*
535 * Find the value entry with the given name in dir, sorting ref_dirs
536 * and recursing into subdirectories as necessary. If the name is not
537 * found or it corresponds to a directory entry, return NULL.
538 */
539 static struct ref_entry *find_ref(struct ref_dir *dir, const char *refname)
540 {
541 int entry_index;
542 struct ref_entry *entry;
543 dir = find_containing_dir(dir, refname, 0);
544 if (!dir)
545 return NULL;
546 entry_index = search_ref_dir(dir, refname, strlen(refname));
547 if (entry_index == -1)
548 return NULL;
549 entry = dir->entries[entry_index];
550 return (entry->flag & REF_DIR) ? NULL : entry;
551 }
552
553 /*
554 * Remove the entry with the given name from dir, recursing into
555 * subdirectories as necessary. If refname is the name of a directory
556 * (i.e., ends with '/'), then remove the directory and its contents.
557 * If the removal was successful, return the number of entries
558 * remaining in the directory entry that contained the deleted entry.
559 * If the name was not found, return -1. Please note that this
560 * function only deletes the entry from the cache; it does not delete
561 * it from the filesystem or ensure that other cache entries (which
562 * might be symbolic references to the removed entry) are updated.
563 * Nor does it remove any containing dir entries that might be made
564 * empty by the removal. dir must represent the top-level directory
565 * and must already be complete.
566 */
567 static int remove_entry(struct ref_dir *dir, const char *refname)
568 {
569 int refname_len = strlen(refname);
570 int entry_index;
571 struct ref_entry *entry;
572 int is_dir = refname[refname_len - 1] == '/';
573 if (is_dir) {
574 /*
575 * refname represents a reference directory. Remove
576 * the trailing slash; otherwise we will get the
577 * directory *representing* refname rather than the
578 * one *containing* it.
579 */
580 char *dirname = xmemdupz(refname, refname_len - 1);
581 dir = find_containing_dir(dir, dirname, 0);
582 free(dirname);
583 } else {
584 dir = find_containing_dir(dir, refname, 0);
585 }
586 if (!dir)
587 return -1;
588 entry_index = search_ref_dir(dir, refname, refname_len);
589 if (entry_index == -1)
590 return -1;
591 entry = dir->entries[entry_index];
592
593 memmove(&dir->entries[entry_index],
594 &dir->entries[entry_index + 1],
595 (dir->nr - entry_index - 1) * sizeof(*dir->entries)
596 );
597 dir->nr--;
598 if (dir->sorted > entry_index)
599 dir->sorted--;
600 free_ref_entry(entry);
601 return dir->nr;
602 }
603
604 /*
605 * Add a ref_entry to the ref_dir (unsorted), recursing into
606 * subdirectories as necessary. dir must represent the top-level
607 * directory. Return 0 on success.
608 */
609 static int add_ref(struct ref_dir *dir, struct ref_entry *ref)
610 {
611 dir = find_containing_dir(dir, ref->name, 1);
612 if (!dir)
613 return -1;
614 add_entry_to_dir(dir, ref);
615 return 0;
616 }
617
618 /*
619 * Emit a warning and return true iff ref1 and ref2 have the same name
620 * and the same sha1. Die if they have the same name but different
621 * sha1s.
622 */
623 static int is_dup_ref(const struct ref_entry *ref1, const struct ref_entry *ref2)
624 {
625 if (strcmp(ref1->name, ref2->name))
626 return 0;
627
628 /* Duplicate name; make sure that they don't conflict: */
629
630 if ((ref1->flag & REF_DIR) || (ref2->flag & REF_DIR))
631 /* This is impossible by construction */
632 die("Reference directory conflict: %s", ref1->name);
633
634 if (oidcmp(&ref1->u.value.oid, &ref2->u.value.oid))
635 die("Duplicated ref, and SHA1s don't match: %s", ref1->name);
636
637 warning("Duplicated ref: %s", ref1->name);
638 return 1;
639 }
640
641 /*
642 * Sort the entries in dir non-recursively (if they are not already
643 * sorted) and remove any duplicate entries.
644 */
645 static void sort_ref_dir(struct ref_dir *dir)
646 {
647 int i, j;
648 struct ref_entry *last = NULL;
649
650 /*
651 * This check also prevents passing a zero-length array to qsort(),
652 * which is a problem on some platforms.
653 */
654 if (dir->sorted == dir->nr)
655 return;
656
657 qsort(dir->entries, dir->nr, sizeof(*dir->entries), ref_entry_cmp);
658
659 /* Remove any duplicates: */
660 for (i = 0, j = 0; j < dir->nr; j++) {
661 struct ref_entry *entry = dir->entries[j];
662 if (last && is_dup_ref(last, entry))
663 free_ref_entry(entry);
664 else
665 last = dir->entries[i++] = entry;
666 }
667 dir->sorted = dir->nr = i;
668 }
669
670 /* Include broken references in a do_for_each_ref*() iteration: */
671 #define DO_FOR_EACH_INCLUDE_BROKEN 0x01
672
673 /*
674 * Return true iff the reference described by entry can be resolved to
675 * an object in the database. Emit a warning if the referred-to
676 * object does not exist.
677 */
678 static int ref_resolves_to_object(struct ref_entry *entry)
679 {
680 if (entry->flag & REF_ISBROKEN)
681 return 0;
682 if (!has_sha1_file(entry->u.value.oid.hash)) {
683 error("%s does not point to a valid object!", entry->name);
684 return 0;
685 }
686 return 1;
687 }
688
689 /*
690 * current_ref is a performance hack: when iterating over references
691 * using the for_each_ref*() functions, current_ref is set to the
692 * current reference's entry before calling the callback function. If
693 * the callback function calls peel_ref(), then peel_ref() first
694 * checks whether the reference to be peeled is the current reference
695 * (it usually is) and if so, returns that reference's peeled version
696 * if it is available. This avoids a refname lookup in a common case.
697 */
698 static struct ref_entry *current_ref;
699
700 typedef int each_ref_entry_fn(struct ref_entry *entry, void *cb_data);
701
702 struct ref_entry_cb {
703 const char *base;
704 int trim;
705 int flags;
706 each_ref_fn *fn;
707 void *cb_data;
708 };
709
710 /*
711 * Handle one reference in a do_for_each_ref*()-style iteration,
712 * calling an each_ref_fn for each entry.
713 */
714 static int do_one_ref(struct ref_entry *entry, void *cb_data)
715 {
716 struct ref_entry_cb *data = cb_data;
717 struct ref_entry *old_current_ref;
718 int retval;
719
720 if (!starts_with(entry->name, data->base))
721 return 0;
722
723 if (!(data->flags & DO_FOR_EACH_INCLUDE_BROKEN) &&
724 !ref_resolves_to_object(entry))
725 return 0;
726
727 /* Store the old value, in case this is a recursive call: */
728 old_current_ref = current_ref;
729 current_ref = entry;
730 retval = data->fn(entry->name + data->trim, &entry->u.value.oid,
731 entry->flag, data->cb_data);
732 current_ref = old_current_ref;
733 return retval;
734 }
735
736 /*
737 * Call fn for each reference in dir that has index in the range
738 * offset <= index < dir->nr. Recurse into subdirectories that are in
739 * that index range, sorting them before iterating. This function
740 * does not sort dir itself; it should be sorted beforehand. fn is
741 * called for all references, including broken ones.
742 */
743 static int do_for_each_entry_in_dir(struct ref_dir *dir, int offset,
744 each_ref_entry_fn fn, void *cb_data)
745 {
746 int i;
747 assert(dir->sorted == dir->nr);
748 for (i = offset; i < dir->nr; i++) {
749 struct ref_entry *entry = dir->entries[i];
750 int retval;
751 if (entry->flag & REF_DIR) {
752 struct ref_dir *subdir = get_ref_dir(entry);
753 sort_ref_dir(subdir);
754 retval = do_for_each_entry_in_dir(subdir, 0, fn, cb_data);
755 } else {
756 retval = fn(entry, cb_data);
757 }
758 if (retval)
759 return retval;
760 }
761 return 0;
762 }
763
764 /*
765 * Call fn for each reference in the union of dir1 and dir2, in order
766 * by refname. Recurse into subdirectories. If a value entry appears
767 * in both dir1 and dir2, then only process the version that is in
768 * dir2. The input dirs must already be sorted, but subdirs will be
769 * sorted as needed. fn is called for all references, including
770 * broken ones.
771 */
772 static int do_for_each_entry_in_dirs(struct ref_dir *dir1,
773 struct ref_dir *dir2,
774 each_ref_entry_fn fn, void *cb_data)
775 {
776 int retval;
777 int i1 = 0, i2 = 0;
778
779 assert(dir1->sorted == dir1->nr);
780 assert(dir2->sorted == dir2->nr);
781 while (1) {
782 struct ref_entry *e1, *e2;
783 int cmp;
784 if (i1 == dir1->nr) {
785 return do_for_each_entry_in_dir(dir2, i2, fn, cb_data);
786 }
787 if (i2 == dir2->nr) {
788 return do_for_each_entry_in_dir(dir1, i1, fn, cb_data);
789 }
790 e1 = dir1->entries[i1];
791 e2 = dir2->entries[i2];
792 cmp = strcmp(e1->name, e2->name);
793 if (cmp == 0) {
794 if ((e1->flag & REF_DIR) && (e2->flag & REF_DIR)) {
795 /* Both are directories; descend them in parallel. */
796 struct ref_dir *subdir1 = get_ref_dir(e1);
797 struct ref_dir *subdir2 = get_ref_dir(e2);
798 sort_ref_dir(subdir1);
799 sort_ref_dir(subdir2);
800 retval = do_for_each_entry_in_dirs(
801 subdir1, subdir2, fn, cb_data);
802 i1++;
803 i2++;
804 } else if (!(e1->flag & REF_DIR) && !(e2->flag & REF_DIR)) {
805 /* Both are references; ignore the one from dir1. */
806 retval = fn(e2, cb_data);
807 i1++;
808 i2++;
809 } else {
810 die("conflict between reference and directory: %s",
811 e1->name);
812 }
813 } else {
814 struct ref_entry *e;
815 if (cmp < 0) {
816 e = e1;
817 i1++;
818 } else {
819 e = e2;
820 i2++;
821 }
822 if (e->flag & REF_DIR) {
823 struct ref_dir *subdir = get_ref_dir(e);
824 sort_ref_dir(subdir);
825 retval = do_for_each_entry_in_dir(
826 subdir, 0, fn, cb_data);
827 } else {
828 retval = fn(e, cb_data);
829 }
830 }
831 if (retval)
832 return retval;
833 }
834 }
835
836 /*
837 * Load all of the refs from the dir into our in-memory cache. The hard work
838 * of loading loose refs is done by get_ref_dir(), so we just need to recurse
839 * through all of the sub-directories. We do not even need to care about
840 * sorting, as traversal order does not matter to us.
841 */
842 static void prime_ref_dir(struct ref_dir *dir)
843 {
844 int i;
845 for (i = 0; i < dir->nr; i++) {
846 struct ref_entry *entry = dir->entries[i];
847 if (entry->flag & REF_DIR)
848 prime_ref_dir(get_ref_dir(entry));
849 }
850 }
851
852 struct nonmatching_ref_data {
853 const struct string_list *skip;
854 const char *conflicting_refname;
855 };
856
857 static int nonmatching_ref_fn(struct ref_entry *entry, void *vdata)
858 {
859 struct nonmatching_ref_data *data = vdata;
860
861 if (data->skip && string_list_has_string(data->skip, entry->name))
862 return 0;
863
864 data->conflicting_refname = entry->name;
865 return 1;
866 }
867
868 /*
869 * Return 0 if a reference named refname could be created without
870 * conflicting with the name of an existing reference in dir.
871 * Otherwise, return a negative value and write an explanation to err.
872 * If extras is non-NULL, it is a list of additional refnames with
873 * which refname is not allowed to conflict. If skip is non-NULL,
874 * ignore potential conflicts with refs in skip (e.g., because they
875 * are scheduled for deletion in the same operation). Behavior is
876 * undefined if the same name is listed in both extras and skip.
877 *
878 * Two reference names conflict if one of them exactly matches the
879 * leading components of the other; e.g., "refs/foo/bar" conflicts
880 * with both "refs/foo" and with "refs/foo/bar/baz" but not with
881 * "refs/foo/bar" or "refs/foo/barbados".
882 *
883 * extras and skip must be sorted.
884 */
885 static int verify_refname_available(const char *refname,
886 const struct string_list *extras,
887 const struct string_list *skip,
888 struct ref_dir *dir,
889 struct strbuf *err)
890 {
891 const char *slash;
892 int pos;
893 struct strbuf dirname = STRBUF_INIT;
894 int ret = -1;
895
896 /*
897 * For the sake of comments in this function, suppose that
898 * refname is "refs/foo/bar".
899 */
900
901 assert(err);
902
903 strbuf_grow(&dirname, strlen(refname) + 1);
904 for (slash = strchr(refname, '/'); slash; slash = strchr(slash + 1, '/')) {
905 /* Expand dirname to the new prefix, not including the trailing slash: */
906 strbuf_add(&dirname, refname + dirname.len, slash - refname - dirname.len);
907
908 /*
909 * We are still at a leading dir of the refname (e.g.,
910 * "refs/foo"; if there is a reference with that name,
911 * it is a conflict, *unless* it is in skip.
912 */
913 if (dir) {
914 pos = search_ref_dir(dir, dirname.buf, dirname.len);
915 if (pos >= 0 &&
916 (!skip || !string_list_has_string(skip, dirname.buf))) {
917 /*
918 * We found a reference whose name is
919 * a proper prefix of refname; e.g.,
920 * "refs/foo", and is not in skip.
921 */
922 strbuf_addf(err, "'%s' exists; cannot create '%s'",
923 dirname.buf, refname);
924 goto cleanup;
925 }
926 }
927
928 if (extras && string_list_has_string(extras, dirname.buf) &&
929 (!skip || !string_list_has_string(skip, dirname.buf))) {
930 strbuf_addf(err, "cannot process '%s' and '%s' at the same time",
931 refname, dirname.buf);
932 goto cleanup;
933 }
934
935 /*
936 * Otherwise, we can try to continue our search with
937 * the next component. So try to look up the
938 * directory, e.g., "refs/foo/". If we come up empty,
939 * we know there is nothing under this whole prefix,
940 * but even in that case we still have to continue the
941 * search for conflicts with extras.
942 */
943 strbuf_addch(&dirname, '/');
944 if (dir) {
945 pos = search_ref_dir(dir, dirname.buf, dirname.len);
946 if (pos < 0) {
947 /*
948 * There was no directory "refs/foo/",
949 * so there is nothing under this
950 * whole prefix. So there is no need
951 * to continue looking for conflicting
952 * references. But we need to continue
953 * looking for conflicting extras.
954 */
955 dir = NULL;
956 } else {
957 dir = get_ref_dir(dir->entries[pos]);
958 }
959 }
960 }
961
962 /*
963 * We are at the leaf of our refname (e.g., "refs/foo/bar").
964 * There is no point in searching for a reference with that
965 * name, because a refname isn't considered to conflict with
966 * itself. But we still need to check for references whose
967 * names are in the "refs/foo/bar/" namespace, because they
968 * *do* conflict.
969 */
970 strbuf_addstr(&dirname, refname + dirname.len);
971 strbuf_addch(&dirname, '/');
972
973 if (dir) {
974 pos = search_ref_dir(dir, dirname.buf, dirname.len);
975
976 if (pos >= 0) {
977 /*
978 * We found a directory named "$refname/"
979 * (e.g., "refs/foo/bar/"). It is a problem
980 * iff it contains any ref that is not in
981 * "skip".
982 */
983 struct nonmatching_ref_data data;
984
985 data.skip = skip;
986 data.conflicting_refname = NULL;
987 dir = get_ref_dir(dir->entries[pos]);
988 sort_ref_dir(dir);
989 if (do_for_each_entry_in_dir(dir, 0, nonmatching_ref_fn, &data)) {
990 strbuf_addf(err, "'%s' exists; cannot create '%s'",
991 data.conflicting_refname, refname);
992 goto cleanup;
993 }
994 }
995 }
996
997 if (extras) {
998 /*
999 * Check for entries in extras that start with
1000 * "$refname/". We do that by looking for the place
1001 * where "$refname/" would be inserted in extras. If
1002 * there is an entry at that position that starts with
1003 * "$refname/" and is not in skip, then we have a
1004 * conflict.
1005 */
1006 for (pos = string_list_find_insert_index(extras, dirname.buf, 0);
1007 pos < extras->nr; pos++) {
1008 const char *extra_refname = extras->items[pos].string;
1009
1010 if (!starts_with(extra_refname, dirname.buf))
1011 break;
1012
1013 if (!skip || !string_list_has_string(skip, extra_refname)) {
1014 strbuf_addf(err, "cannot process '%s' and '%s' at the same time",
1015 refname, extra_refname);
1016 goto cleanup;
1017 }
1018 }
1019 }
1020
1021 /* No conflicts were found */
1022 ret = 0;
1023
1024 cleanup:
1025 strbuf_release(&dirname);
1026 return ret;
1027 }
1028
1029 struct packed_ref_cache {
1030 struct ref_entry *root;
1031
1032 /*
1033 * Count of references to the data structure in this instance,
1034 * including the pointer from ref_cache::packed if any. The
1035 * data will not be freed as long as the reference count is
1036 * nonzero.
1037 */
1038 unsigned int referrers;
1039
1040 /*
1041 * Iff the packed-refs file associated with this instance is
1042 * currently locked for writing, this points at the associated
1043 * lock (which is owned by somebody else). The referrer count
1044 * is also incremented when the file is locked and decremented
1045 * when it is unlocked.
1046 */
1047 struct lock_file *lock;
1048
1049 /* The metadata from when this packed-refs cache was read */
1050 struct stat_validity validity;
1051 };
1052
1053 /*
1054 * Future: need to be in "struct repository"
1055 * when doing a full libification.
1056 */
1057 static struct ref_cache {
1058 struct ref_cache *next;
1059 struct ref_entry *loose;
1060 struct packed_ref_cache *packed;
1061 /*
1062 * The submodule name, or "" for the main repo. We allocate
1063 * length 1 rather than FLEX_ARRAY so that the main ref_cache
1064 * is initialized correctly.
1065 */
1066 char name[1];
1067 } ref_cache, *submodule_ref_caches;
1068
1069 /* Lock used for the main packed-refs file: */
1070 static struct lock_file packlock;
1071
1072 /*
1073 * Increment the reference count of *packed_refs.
1074 */
1075 static void acquire_packed_ref_cache(struct packed_ref_cache *packed_refs)
1076 {
1077 packed_refs->referrers++;
1078 }
1079
1080 /*
1081 * Decrease the reference count of *packed_refs. If it goes to zero,
1082 * free *packed_refs and return true; otherwise return false.
1083 */
1084 static int release_packed_ref_cache(struct packed_ref_cache *packed_refs)
1085 {
1086 if (!--packed_refs->referrers) {
1087 free_ref_entry(packed_refs->root);
1088 stat_validity_clear(&packed_refs->validity);
1089 free(packed_refs);
1090 return 1;
1091 } else {
1092 return 0;
1093 }
1094 }
1095
1096 static void clear_packed_ref_cache(struct ref_cache *refs)
1097 {
1098 if (refs->packed) {
1099 struct packed_ref_cache *packed_refs = refs->packed;
1100
1101 if (packed_refs->lock)
1102 die("internal error: packed-ref cache cleared while locked");
1103 refs->packed = NULL;
1104 release_packed_ref_cache(packed_refs);
1105 }
1106 }
1107
1108 static void clear_loose_ref_cache(struct ref_cache *refs)
1109 {
1110 if (refs->loose) {
1111 free_ref_entry(refs->loose);
1112 refs->loose = NULL;
1113 }
1114 }
1115
1116 static struct ref_cache *create_ref_cache(const char *submodule)
1117 {
1118 int len;
1119 struct ref_cache *refs;
1120 if (!submodule)
1121 submodule = "";
1122 len = strlen(submodule) + 1;
1123 refs = xcalloc(1, sizeof(struct ref_cache) + len);
1124 memcpy(refs->name, submodule, len);
1125 return refs;
1126 }
1127
1128 /*
1129 * Return a pointer to a ref_cache for the specified submodule. For
1130 * the main repository, use submodule==NULL. The returned structure
1131 * will be allocated and initialized but not necessarily populated; it
1132 * should not be freed.
1133 */
1134 static struct ref_cache *get_ref_cache(const char *submodule)
1135 {
1136 struct ref_cache *refs;
1137
1138 if (!submodule || !*submodule)
1139 return &ref_cache;
1140
1141 for (refs = submodule_ref_caches; refs; refs = refs->next)
1142 if (!strcmp(submodule, refs->name))
1143 return refs;
1144
1145 refs = create_ref_cache(submodule);
1146 refs->next = submodule_ref_caches;
1147 submodule_ref_caches = refs;
1148 return refs;
1149 }
1150
1151 /* The length of a peeled reference line in packed-refs, including EOL: */
1152 #define PEELED_LINE_LENGTH 42
1153
1154 /*
1155 * The packed-refs header line that we write out. Perhaps other
1156 * traits will be added later. The trailing space is required.
1157 */
1158 static const char PACKED_REFS_HEADER[] =
1159 "# pack-refs with: peeled fully-peeled \n";
1160
1161 /*
1162 * Parse one line from a packed-refs file. Write the SHA1 to sha1.
1163 * Return a pointer to the refname within the line (null-terminated),
1164 * or NULL if there was a problem.
1165 */
1166 static const char *parse_ref_line(struct strbuf *line, unsigned char *sha1)
1167 {
1168 const char *ref;
1169
1170 /*
1171 * 42: the answer to everything.
1172 *
1173 * In this case, it happens to be the answer to
1174 * 40 (length of sha1 hex representation)
1175 * +1 (space in between hex and name)
1176 * +1 (newline at the end of the line)
1177 */
1178 if (line->len <= 42)
1179 return NULL;
1180
1181 if (get_sha1_hex(line->buf, sha1) < 0)
1182 return NULL;
1183 if (!isspace(line->buf[40]))
1184 return NULL;
1185
1186 ref = line->buf + 41;
1187 if (isspace(*ref))
1188 return NULL;
1189
1190 if (line->buf[line->len - 1] != '\n')
1191 return NULL;
1192 line->buf[--line->len] = 0;
1193
1194 return ref;
1195 }
1196
1197 /*
1198 * Read f, which is a packed-refs file, into dir.
1199 *
1200 * A comment line of the form "# pack-refs with: " may contain zero or
1201 * more traits. We interpret the traits as follows:
1202 *
1203 * No traits:
1204 *
1205 * Probably no references are peeled. But if the file contains a
1206 * peeled value for a reference, we will use it.
1207 *
1208 * peeled:
1209 *
1210 * References under "refs/tags/", if they *can* be peeled, *are*
1211 * peeled in this file. References outside of "refs/tags/" are
1212 * probably not peeled even if they could have been, but if we find
1213 * a peeled value for such a reference we will use it.
1214 *
1215 * fully-peeled:
1216 *
1217 * All references in the file that can be peeled are peeled.
1218 * Inversely (and this is more important), any references in the
1219 * file for which no peeled value is recorded is not peelable. This
1220 * trait should typically be written alongside "peeled" for
1221 * compatibility with older clients, but we do not require it
1222 * (i.e., "peeled" is a no-op if "fully-peeled" is set).
1223 */
1224 static void read_packed_refs(FILE *f, struct ref_dir *dir)
1225 {
1226 struct ref_entry *last = NULL;
1227 struct strbuf line = STRBUF_INIT;
1228 enum { PEELED_NONE, PEELED_TAGS, PEELED_FULLY } peeled = PEELED_NONE;
1229
1230 while (strbuf_getwholeline(&line, f, '\n') != EOF) {
1231 unsigned char sha1[20];
1232 const char *refname;
1233 const char *traits;
1234
1235 if (skip_prefix(line.buf, "# pack-refs with:", &traits)) {
1236 if (strstr(traits, " fully-peeled "))
1237 peeled = PEELED_FULLY;
1238 else if (strstr(traits, " peeled "))
1239 peeled = PEELED_TAGS;
1240 /* perhaps other traits later as well */
1241 continue;
1242 }
1243
1244 refname = parse_ref_line(&line, sha1);
1245 if (refname) {
1246 int flag = REF_ISPACKED;
1247
1248 if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
1249 if (!refname_is_safe(refname))
1250 die("packed refname is dangerous: %s", refname);
1251 hashclr(sha1);
1252 flag |= REF_BAD_NAME | REF_ISBROKEN;
1253 }
1254 last = create_ref_entry(refname, sha1, flag, 0);
1255 if (peeled == PEELED_FULLY ||
1256 (peeled == PEELED_TAGS && starts_with(refname, "refs/tags/")))
1257 last->flag |= REF_KNOWS_PEELED;
1258 add_ref(dir, last);
1259 continue;
1260 }
1261 if (last &&
1262 line.buf[0] == '^' &&
1263 line.len == PEELED_LINE_LENGTH &&
1264 line.buf[PEELED_LINE_LENGTH - 1] == '\n' &&
1265 !get_sha1_hex(line.buf + 1, sha1)) {
1266 hashcpy(last->u.value.peeled.hash, sha1);
1267 /*
1268 * Regardless of what the file header said,
1269 * we definitely know the value of *this*
1270 * reference:
1271 */
1272 last->flag |= REF_KNOWS_PEELED;
1273 }
1274 }
1275
1276 strbuf_release(&line);
1277 }
1278
1279 /*
1280 * Get the packed_ref_cache for the specified ref_cache, creating it
1281 * if necessary.
1282 */
1283 static struct packed_ref_cache *get_packed_ref_cache(struct ref_cache *refs)
1284 {
1285 const char *packed_refs_file;
1286
1287 if (*refs->name)
1288 packed_refs_file = git_path_submodule(refs->name, "packed-refs");
1289 else
1290 packed_refs_file = git_path("packed-refs");
1291
1292 if (refs->packed &&
1293 !stat_validity_check(&refs->packed->validity, packed_refs_file))
1294 clear_packed_ref_cache(refs);
1295
1296 if (!refs->packed) {
1297 FILE *f;
1298
1299 refs->packed = xcalloc(1, sizeof(*refs->packed));
1300 acquire_packed_ref_cache(refs->packed);
1301 refs->packed->root = create_dir_entry(refs, "", 0, 0);
1302 f = fopen(packed_refs_file, "r");
1303 if (f) {
1304 stat_validity_update(&refs->packed->validity, fileno(f));
1305 read_packed_refs(f, get_ref_dir(refs->packed->root));
1306 fclose(f);
1307 }
1308 }
1309 return refs->packed;
1310 }
1311
1312 static struct ref_dir *get_packed_ref_dir(struct packed_ref_cache *packed_ref_cache)
1313 {
1314 return get_ref_dir(packed_ref_cache->root);
1315 }
1316
1317 static struct ref_dir *get_packed_refs(struct ref_cache *refs)
1318 {
1319 return get_packed_ref_dir(get_packed_ref_cache(refs));
1320 }
1321
1322 void add_packed_ref(const char *refname, const unsigned char *sha1)
1323 {
1324 struct packed_ref_cache *packed_ref_cache =
1325 get_packed_ref_cache(&ref_cache);
1326
1327 if (!packed_ref_cache->lock)
1328 die("internal error: packed refs not locked");
1329 add_ref(get_packed_ref_dir(packed_ref_cache),
1330 create_ref_entry(refname, sha1, REF_ISPACKED, 1));
1331 }
1332
1333 /*
1334 * Read the loose references from the namespace dirname into dir
1335 * (without recursing). dirname must end with '/'. dir must be the
1336 * directory entry corresponding to dirname.
1337 */
1338 static void read_loose_refs(const char *dirname, struct ref_dir *dir)
1339 {
1340 struct ref_cache *refs = dir->ref_cache;
1341 DIR *d;
1342 const char *path;
1343 struct dirent *de;
1344 int dirnamelen = strlen(dirname);
1345 struct strbuf refname;
1346
1347 if (*refs->name)
1348 path = git_path_submodule(refs->name, "%s", dirname);
1349 else
1350 path = git_path("%s", dirname);
1351
1352 d = opendir(path);
1353 if (!d)
1354 return;
1355
1356 strbuf_init(&refname, dirnamelen + 257);
1357 strbuf_add(&refname, dirname, dirnamelen);
1358
1359 while ((de = readdir(d)) != NULL) {
1360 unsigned char sha1[20];
1361 struct stat st;
1362 int flag;
1363 const char *refdir;
1364
1365 if (de->d_name[0] == '.')
1366 continue;
1367 if (ends_with(de->d_name, ".lock"))
1368 continue;
1369 strbuf_addstr(&refname, de->d_name);
1370 refdir = *refs->name
1371 ? git_path_submodule(refs->name, "%s", refname.buf)
1372 : git_path("%s", refname.buf);
1373 if (stat(refdir, &st) < 0) {
1374 ; /* silently ignore */
1375 } else if (S_ISDIR(st.st_mode)) {
1376 strbuf_addch(&refname, '/');
1377 add_entry_to_dir(dir,
1378 create_dir_entry(refs, refname.buf,
1379 refname.len, 1));
1380 } else {
1381 int read_ok;
1382
1383 if (*refs->name) {
1384 hashclr(sha1);
1385 flag = 0;
1386 read_ok = !resolve_gitlink_ref(refs->name,
1387 refname.buf, sha1);
1388 } else {
1389 read_ok = !read_ref_full(refname.buf,
1390 RESOLVE_REF_READING,
1391 sha1, &flag);
1392 }
1393
1394 if (!read_ok) {
1395 hashclr(sha1);
1396 flag |= REF_ISBROKEN;
1397 } else if (is_null_sha1(sha1)) {
1398 /*
1399 * It is so astronomically unlikely
1400 * that NULL_SHA1 is the SHA-1 of an
1401 * actual object that we consider its
1402 * appearance in a loose reference
1403 * file to be repo corruption
1404 * (probably due to a software bug).
1405 */
1406 flag |= REF_ISBROKEN;
1407 }
1408
1409 if (check_refname_format(refname.buf,
1410 REFNAME_ALLOW_ONELEVEL)) {
1411 if (!refname_is_safe(refname.buf))
1412 die("loose refname is dangerous: %s", refname.buf);
1413 hashclr(sha1);
1414 flag |= REF_BAD_NAME | REF_ISBROKEN;
1415 }
1416 add_entry_to_dir(dir,
1417 create_ref_entry(refname.buf, sha1, flag, 0));
1418 }
1419 strbuf_setlen(&refname, dirnamelen);
1420 }
1421 strbuf_release(&refname);
1422 closedir(d);
1423 }
1424
1425 static struct ref_dir *get_loose_refs(struct ref_cache *refs)
1426 {
1427 if (!refs->loose) {
1428 /*
1429 * Mark the top-level directory complete because we
1430 * are about to read the only subdirectory that can
1431 * hold references:
1432 */
1433 refs->loose = create_dir_entry(refs, "", 0, 0);
1434 /*
1435 * Create an incomplete entry for "refs/":
1436 */
1437 add_entry_to_dir(get_ref_dir(refs->loose),
1438 create_dir_entry(refs, "refs/", 5, 1));
1439 }
1440 return get_ref_dir(refs->loose);
1441 }
1442
1443 /* We allow "recursive" symbolic refs. Only within reason, though */
1444 #define MAXDEPTH 5
1445 #define MAXREFLEN (1024)
1446
1447 /*
1448 * Called by resolve_gitlink_ref_recursive() after it failed to read
1449 * from the loose refs in ref_cache refs. Find <refname> in the
1450 * packed-refs file for the submodule.
1451 */
1452 static int resolve_gitlink_packed_ref(struct ref_cache *refs,
1453 const char *refname, unsigned char *sha1)
1454 {
1455 struct ref_entry *ref;
1456 struct ref_dir *dir = get_packed_refs(refs);
1457
1458 ref = find_ref(dir, refname);
1459 if (ref == NULL)
1460 return -1;
1461
1462 hashcpy(sha1, ref->u.value.oid.hash);
1463 return 0;
1464 }
1465
1466 static int resolve_gitlink_ref_recursive(struct ref_cache *refs,
1467 const char *refname, unsigned char *sha1,
1468 int recursion)
1469 {
1470 int fd, len;
1471 char buffer[128], *p;
1472 const char *path;
1473
1474 if (recursion > MAXDEPTH || strlen(refname) > MAXREFLEN)
1475 return -1;
1476 path = *refs->name
1477 ? git_path_submodule(refs->name, "%s", refname)
1478 : git_path("%s", refname);
1479 fd = open(path, O_RDONLY);
1480 if (fd < 0)
1481 return resolve_gitlink_packed_ref(refs, refname, sha1);
1482
1483 len = read(fd, buffer, sizeof(buffer)-1);
1484 close(fd);
1485 if (len < 0)
1486 return -1;
1487 while (len && isspace(buffer[len-1]))
1488 len--;
1489 buffer[len] = 0;
1490
1491 /* Was it a detached head or an old-fashioned symlink? */
1492 if (!get_sha1_hex(buffer, sha1))
1493 return 0;
1494
1495 /* Symref? */
1496 if (strncmp(buffer, "ref:", 4))
1497 return -1;
1498 p = buffer + 4;
1499 while (isspace(*p))
1500 p++;
1501
1502 return resolve_gitlink_ref_recursive(refs, p, sha1, recursion+1);
1503 }
1504
1505 int resolve_gitlink_ref(const char *path, const char *refname, unsigned char *sha1)
1506 {
1507 int len = strlen(path), retval;
1508 char *submodule;
1509 struct ref_cache *refs;
1510
1511 while (len && path[len-1] == '/')
1512 len--;
1513 if (!len)
1514 return -1;
1515 submodule = xstrndup(path, len);
1516 refs = get_ref_cache(submodule);
1517 free(submodule);
1518
1519 retval = resolve_gitlink_ref_recursive(refs, refname, sha1, 0);
1520 return retval;
1521 }
1522
1523 /*
1524 * Return the ref_entry for the given refname from the packed
1525 * references. If it does not exist, return NULL.
1526 */
1527 static struct ref_entry *get_packed_ref(const char *refname)
1528 {
1529 return find_ref(get_packed_refs(&ref_cache), refname);
1530 }
1531
1532 /*
1533 * A loose ref file doesn't exist; check for a packed ref. The
1534 * options are forwarded from resolve_safe_unsafe().
1535 */
1536 static int resolve_missing_loose_ref(const char *refname,
1537 int resolve_flags,
1538 unsigned char *sha1,
1539 int *flags)
1540 {
1541 struct ref_entry *entry;
1542
1543 /*
1544 * The loose reference file does not exist; check for a packed
1545 * reference.
1546 */
1547 entry = get_packed_ref(refname);
1548 if (entry) {
1549 hashcpy(sha1, entry->u.value.oid.hash);
1550 if (flags)
1551 *flags |= REF_ISPACKED;
1552 return 0;
1553 }
1554 /* The reference is not a packed reference, either. */
1555 if (resolve_flags & RESOLVE_REF_READING) {
1556 errno = ENOENT;
1557 return -1;
1558 } else {
1559 hashclr(sha1);
1560 return 0;
1561 }
1562 }
1563
1564 /* This function needs to return a meaningful errno on failure */
1565 static const char *resolve_ref_unsafe_1(const char *refname,
1566 int resolve_flags,
1567 unsigned char *sha1,
1568 int *flags,
1569 struct strbuf *sb_path)
1570 {
1571 int depth = MAXDEPTH;
1572 ssize_t len;
1573 char buffer[256];
1574 static char refname_buffer[256];
1575 int bad_name = 0;
1576
1577 if (flags)
1578 *flags = 0;
1579
1580 if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
1581 if (flags)
1582 *flags |= REF_BAD_NAME;
1583
1584 if (!(resolve_flags & RESOLVE_REF_ALLOW_BAD_NAME) ||
1585 !refname_is_safe(refname)) {
1586 errno = EINVAL;
1587 return NULL;
1588 }
1589 /*
1590 * dwim_ref() uses REF_ISBROKEN to distinguish between
1591 * missing refs and refs that were present but invalid,
1592 * to complain about the latter to stderr.
1593 *
1594 * We don't know whether the ref exists, so don't set
1595 * REF_ISBROKEN yet.
1596 */
1597 bad_name = 1;
1598 }
1599 for (;;) {
1600 const char *path;
1601 struct stat st;
1602 char *buf;
1603 int fd;
1604
1605 if (--depth < 0) {
1606 errno = ELOOP;
1607 return NULL;
1608 }
1609
1610 strbuf_reset(sb_path);
1611 strbuf_git_path(sb_path, "%s", refname);
1612 path = sb_path->buf;
1613
1614 /*
1615 * We might have to loop back here to avoid a race
1616 * condition: first we lstat() the file, then we try
1617 * to read it as a link or as a file. But if somebody
1618 * changes the type of the file (file <-> directory
1619 * <-> symlink) between the lstat() and reading, then
1620 * we don't want to report that as an error but rather
1621 * try again starting with the lstat().
1622 */
1623 stat_ref:
1624 if (lstat(path, &st) < 0) {
1625 if (errno != ENOENT)
1626 return NULL;
1627 if (resolve_missing_loose_ref(refname, resolve_flags,
1628 sha1, flags))
1629 return NULL;
1630 if (bad_name) {
1631 hashclr(sha1);
1632 if (flags)
1633 *flags |= REF_ISBROKEN;
1634 }
1635 return refname;
1636 }
1637
1638 /* Follow "normalized" - ie "refs/.." symlinks by hand */
1639 if (S_ISLNK(st.st_mode)) {
1640 len = readlink(path, buffer, sizeof(buffer)-1);
1641 if (len < 0) {
1642 if (errno == ENOENT || errno == EINVAL)
1643 /* inconsistent with lstat; retry */
1644 goto stat_ref;
1645 else
1646 return NULL;
1647 }
1648 buffer[len] = 0;
1649 if (starts_with(buffer, "refs/") &&
1650 !check_refname_format(buffer, 0)) {
1651 strcpy(refname_buffer, buffer);
1652 refname = refname_buffer;
1653 if (flags)
1654 *flags |= REF_ISSYMREF;
1655 if (resolve_flags & RESOLVE_REF_NO_RECURSE) {
1656 hashclr(sha1);
1657 return refname;
1658 }
1659 continue;
1660 }
1661 }
1662
1663 /* Is it a directory? */
1664 if (S_ISDIR(st.st_mode)) {
1665 errno = EISDIR;
1666 return NULL;
1667 }
1668
1669 /*
1670 * Anything else, just open it and try to use it as
1671 * a ref
1672 */
1673 fd = open(path, O_RDONLY);
1674 if (fd < 0) {
1675 if (errno == ENOENT)
1676 /* inconsistent with lstat; retry */
1677 goto stat_ref;
1678 else
1679 return NULL;
1680 }
1681 len = read_in_full(fd, buffer, sizeof(buffer)-1);
1682 if (len < 0) {
1683 int save_errno = errno;
1684 close(fd);
1685 errno = save_errno;
1686 return NULL;
1687 }
1688 close(fd);
1689 while (len && isspace(buffer[len-1]))
1690 len--;
1691 buffer[len] = '\0';
1692
1693 /*
1694 * Is it a symbolic ref?
1695 */
1696 if (!starts_with(buffer, "ref:")) {
1697 /*
1698 * Please note that FETCH_HEAD has a second
1699 * line containing other data.
1700 */
1701 if (get_sha1_hex(buffer, sha1) ||
1702 (buffer[40] != '\0' && !isspace(buffer[40]))) {
1703 if (flags)
1704 *flags |= REF_ISBROKEN;
1705 errno = EINVAL;
1706 return NULL;
1707 }
1708 if (bad_name) {
1709 hashclr(sha1);
1710 if (flags)
1711 *flags |= REF_ISBROKEN;
1712 }
1713 return refname;
1714 }
1715 if (flags)
1716 *flags |= REF_ISSYMREF;
1717 buf = buffer + 4;
1718 while (isspace(*buf))
1719 buf++;
1720 refname = strcpy(refname_buffer, buf);
1721 if (resolve_flags & RESOLVE_REF_NO_RECURSE) {
1722 hashclr(sha1);
1723 return refname;
1724 }
1725 if (check_refname_format(buf, REFNAME_ALLOW_ONELEVEL)) {
1726 if (flags)
1727 *flags |= REF_ISBROKEN;
1728
1729 if (!(resolve_flags & RESOLVE_REF_ALLOW_BAD_NAME) ||
1730 !refname_is_safe(buf)) {
1731 errno = EINVAL;
1732 return NULL;
1733 }
1734 bad_name = 1;
1735 }
1736 }
1737 }
1738
1739 const char *resolve_ref_unsafe(const char *refname, int resolve_flags,
1740 unsigned char *sha1, int *flags)
1741 {
1742 struct strbuf sb_path = STRBUF_INIT;
1743 const char *ret = resolve_ref_unsafe_1(refname, resolve_flags,
1744 sha1, flags, &sb_path);
1745 strbuf_release(&sb_path);
1746 return ret;
1747 }
1748
1749 char *resolve_refdup(const char *ref, int resolve_flags, unsigned char *sha1, int *flags)
1750 {
1751 return xstrdup_or_null(resolve_ref_unsafe(ref, resolve_flags, sha1, flags));
1752 }
1753
1754 /* The argument to filter_refs */
1755 struct ref_filter {
1756 const char *pattern;
1757 each_ref_fn *fn;
1758 void *cb_data;
1759 };
1760
1761 int read_ref_full(const char *refname, int resolve_flags, unsigned char *sha1, int *flags)
1762 {
1763 if (resolve_ref_unsafe(refname, resolve_flags, sha1, flags))
1764 return 0;
1765 return -1;
1766 }
1767
1768 int read_ref(const char *refname, unsigned char *sha1)
1769 {
1770 return read_ref_full(refname, RESOLVE_REF_READING, sha1, NULL);
1771 }
1772
1773 int ref_exists(const char *refname)
1774 {
1775 unsigned char sha1[20];
1776 return !!resolve_ref_unsafe(refname, RESOLVE_REF_READING, sha1, NULL);
1777 }
1778
1779 static int filter_refs(const char *refname, const struct object_id *oid,
1780 int flags, void *data)
1781 {
1782 struct ref_filter *filter = (struct ref_filter *)data;
1783
1784 if (wildmatch(filter->pattern, refname, 0, NULL))
1785 return 0;
1786 return filter->fn(refname, oid, flags, filter->cb_data);
1787 }
1788
1789 enum peel_status {
1790 /* object was peeled successfully: */
1791 PEEL_PEELED = 0,
1792
1793 /*
1794 * object cannot be peeled because the named object (or an
1795 * object referred to by a tag in the peel chain), does not
1796 * exist.
1797 */
1798 PEEL_INVALID = -1,
1799
1800 /* object cannot be peeled because it is not a tag: */
1801 PEEL_NON_TAG = -2,
1802
1803 /* ref_entry contains no peeled value because it is a symref: */
1804 PEEL_IS_SYMREF = -3,
1805
1806 /*
1807 * ref_entry cannot be peeled because it is broken (i.e., the
1808 * symbolic reference cannot even be resolved to an object
1809 * name):
1810 */
1811 PEEL_BROKEN = -4
1812 };
1813
1814 /*
1815 * Peel the named object; i.e., if the object is a tag, resolve the
1816 * tag recursively until a non-tag is found. If successful, store the
1817 * result to sha1 and return PEEL_PEELED. If the object is not a tag
1818 * or is not valid, return PEEL_NON_TAG or PEEL_INVALID, respectively,
1819 * and leave sha1 unchanged.
1820 */
1821 static enum peel_status peel_object(const unsigned char *name, unsigned char *sha1)
1822 {
1823 struct object *o = lookup_unknown_object(name);
1824
1825 if (o->type == OBJ_NONE) {
1826 int type = sha1_object_info(name, NULL);
1827 if (type < 0 || !object_as_type(o, type, 0))
1828 return PEEL_INVALID;
1829 }
1830
1831 if (o->type != OBJ_TAG)
1832 return PEEL_NON_TAG;
1833
1834 o = deref_tag_noverify(o);
1835 if (!o)
1836 return PEEL_INVALID;
1837
1838 hashcpy(sha1, o->sha1);
1839 return PEEL_PEELED;
1840 }
1841
1842 /*
1843 * Peel the entry (if possible) and return its new peel_status. If
1844 * repeel is true, re-peel the entry even if there is an old peeled
1845 * value that is already stored in it.
1846 *
1847 * It is OK to call this function with a packed reference entry that
1848 * might be stale and might even refer to an object that has since
1849 * been garbage-collected. In such a case, if the entry has
1850 * REF_KNOWS_PEELED then leave the status unchanged and return
1851 * PEEL_PEELED or PEEL_NON_TAG; otherwise, return PEEL_INVALID.
1852 */
1853 static enum peel_status peel_entry(struct ref_entry *entry, int repeel)
1854 {
1855 enum peel_status status;
1856
1857 if (entry->flag & REF_KNOWS_PEELED) {
1858 if (repeel) {
1859 entry->flag &= ~REF_KNOWS_PEELED;
1860 oidclr(&entry->u.value.peeled);
1861 } else {
1862 return is_null_oid(&entry->u.value.peeled) ?
1863 PEEL_NON_TAG : PEEL_PEELED;
1864 }
1865 }
1866 if (entry->flag & REF_ISBROKEN)
1867 return PEEL_BROKEN;
1868 if (entry->flag & REF_ISSYMREF)
1869 return PEEL_IS_SYMREF;
1870
1871 status = peel_object(entry->u.value.oid.hash, entry->u.value.peeled.hash);
1872 if (status == PEEL_PEELED || status == PEEL_NON_TAG)
1873 entry->flag |= REF_KNOWS_PEELED;
1874 return status;
1875 }
1876
1877 int peel_ref(const char *refname, unsigned char *sha1)
1878 {
1879 int flag;
1880 unsigned char base[20];
1881
1882 if (current_ref && (current_ref->name == refname
1883 || !strcmp(current_ref->name, refname))) {
1884 if (peel_entry(current_ref, 0))
1885 return -1;
1886 hashcpy(sha1, current_ref->u.value.peeled.hash);
1887 return 0;
1888 }
1889
1890 if (read_ref_full(refname, RESOLVE_REF_READING, base, &flag))
1891 return -1;
1892
1893 /*
1894 * If the reference is packed, read its ref_entry from the
1895 * cache in the hope that we already know its peeled value.
1896 * We only try this optimization on packed references because
1897 * (a) forcing the filling of the loose reference cache could
1898 * be expensive and (b) loose references anyway usually do not
1899 * have REF_KNOWS_PEELED.
1900 */
1901 if (flag & REF_ISPACKED) {
1902 struct ref_entry *r = get_packed_ref(refname);
1903 if (r) {
1904 if (peel_entry(r, 0))
1905 return -1;
1906 hashcpy(sha1, r->u.value.peeled.hash);
1907 return 0;
1908 }
1909 }
1910
1911 return peel_object(base, sha1);
1912 }
1913
1914 struct warn_if_dangling_data {
1915 FILE *fp;
1916 const char *refname;
1917 const struct string_list *refnames;
1918 const char *msg_fmt;
1919 };
1920
1921 static int warn_if_dangling_symref(const char *refname, const struct object_id *oid,
1922 int flags, void *cb_data)
1923 {
1924 struct warn_if_dangling_data *d = cb_data;
1925 const char *resolves_to;
1926 struct object_id junk;
1927
1928 if (!(flags & REF_ISSYMREF))
1929 return 0;
1930
1931 resolves_to = resolve_ref_unsafe(refname, 0, junk.hash, NULL);
1932 if (!resolves_to
1933 || (d->refname
1934 ? strcmp(resolves_to, d->refname)
1935 : !string_list_has_string(d->refnames, resolves_to))) {
1936 return 0;
1937 }
1938
1939 fprintf(d->fp, d->msg_fmt, refname);
1940 fputc('\n', d->fp);
1941 return 0;
1942 }
1943
1944 void warn_dangling_symref(FILE *fp, const char *msg_fmt, const char *refname)
1945 {
1946 struct warn_if_dangling_data data;
1947
1948 data.fp = fp;
1949 data.refname = refname;
1950 data.refnames = NULL;
1951 data.msg_fmt = msg_fmt;
1952 for_each_rawref(warn_if_dangling_symref, &data);
1953 }
1954
1955 void warn_dangling_symrefs(FILE *fp, const char *msg_fmt, const struct string_list *refnames)
1956 {
1957 struct warn_if_dangling_data data;
1958
1959 data.fp = fp;
1960 data.refname = NULL;
1961 data.refnames = refnames;
1962 data.msg_fmt = msg_fmt;
1963 for_each_rawref(warn_if_dangling_symref, &data);
1964 }
1965
1966 /*
1967 * Call fn for each reference in the specified ref_cache, omitting
1968 * references not in the containing_dir of base. fn is called for all
1969 * references, including broken ones. If fn ever returns a non-zero
1970 * value, stop the iteration and return that value; otherwise, return
1971 * 0.
1972 */
1973 static int do_for_each_entry(struct ref_cache *refs, const char *base,
1974 each_ref_entry_fn fn, void *cb_data)
1975 {
1976 struct packed_ref_cache *packed_ref_cache;
1977 struct ref_dir *loose_dir;
1978 struct ref_dir *packed_dir;
1979 int retval = 0;
1980
1981 /*
1982 * We must make sure that all loose refs are read before accessing the
1983 * packed-refs file; this avoids a race condition in which loose refs
1984 * are migrated to the packed-refs file by a simultaneous process, but
1985 * our in-memory view is from before the migration. get_packed_ref_cache()
1986 * takes care of making sure our view is up to date with what is on
1987 * disk.
1988 */
1989 loose_dir = get_loose_refs(refs);
1990 if (base && *base) {
1991 loose_dir = find_containing_dir(loose_dir, base, 0);
1992 }
1993 if (loose_dir)
1994 prime_ref_dir(loose_dir);
1995
1996 packed_ref_cache = get_packed_ref_cache(refs);
1997 acquire_packed_ref_cache(packed_ref_cache);
1998 packed_dir = get_packed_ref_dir(packed_ref_cache);
1999 if (base && *base) {
2000 packed_dir = find_containing_dir(packed_dir, base, 0);
2001 }
2002
2003 if (packed_dir && loose_dir) {
2004 sort_ref_dir(packed_dir);
2005 sort_ref_dir(loose_dir);
2006 retval = do_for_each_entry_in_dirs(
2007 packed_dir, loose_dir, fn, cb_data);
2008 } else if (packed_dir) {
2009 sort_ref_dir(packed_dir);
2010 retval = do_for_each_entry_in_dir(
2011 packed_dir, 0, fn, cb_data);
2012 } else if (loose_dir) {
2013 sort_ref_dir(loose_dir);
2014 retval = do_for_each_entry_in_dir(
2015 loose_dir, 0, fn, cb_data);
2016 }
2017
2018 release_packed_ref_cache(packed_ref_cache);
2019 return retval;
2020 }
2021
2022 /*
2023 * Call fn for each reference in the specified ref_cache for which the
2024 * refname begins with base. If trim is non-zero, then trim that many
2025 * characters off the beginning of each refname before passing the
2026 * refname to fn. flags can be DO_FOR_EACH_INCLUDE_BROKEN to include
2027 * broken references in the iteration. If fn ever returns a non-zero
2028 * value, stop the iteration and return that value; otherwise, return
2029 * 0.
2030 */
2031 static int do_for_each_ref(struct ref_cache *refs, const char *base,
2032 each_ref_fn fn, int trim, int flags, void *cb_data)
2033 {
2034 struct ref_entry_cb data;
2035 data.base = base;
2036 data.trim = trim;
2037 data.flags = flags;
2038 data.fn = fn;
2039 data.cb_data = cb_data;
2040
2041 if (ref_paranoia < 0)
2042 ref_paranoia = git_env_bool("GIT_REF_PARANOIA", 0);
2043 if (ref_paranoia)
2044 data.flags |= DO_FOR_EACH_INCLUDE_BROKEN;
2045
2046 return do_for_each_entry(refs, base, do_one_ref, &data);
2047 }
2048
2049 static int do_head_ref(const char *submodule, each_ref_fn fn, void *cb_data)
2050 {
2051 struct object_id oid;
2052 int flag;
2053
2054 if (submodule) {
2055 if (resolve_gitlink_ref(submodule, "HEAD", oid.hash) == 0)
2056 return fn("HEAD", &oid, 0, cb_data);
2057
2058 return 0;
2059 }
2060
2061 if (!read_ref_full("HEAD", RESOLVE_REF_READING, oid.hash, &flag))
2062 return fn("HEAD", &oid, flag, cb_data);
2063
2064 return 0;
2065 }
2066
2067 int head_ref(each_ref_fn fn, void *cb_data)
2068 {
2069 return do_head_ref(NULL, fn, cb_data);
2070 }
2071
2072 int head_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
2073 {
2074 return do_head_ref(submodule, fn, cb_data);
2075 }
2076
2077 int for_each_ref(each_ref_fn fn, void *cb_data)
2078 {
2079 return do_for_each_ref(&ref_cache, "", fn, 0, 0, cb_data);
2080 }
2081
2082 int for_each_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
2083 {
2084 return do_for_each_ref(get_ref_cache(submodule), "", fn, 0, 0, cb_data);
2085 }
2086
2087 int for_each_ref_in(const char *prefix, each_ref_fn fn, void *cb_data)
2088 {
2089 return do_for_each_ref(&ref_cache, prefix, fn, strlen(prefix), 0, cb_data);
2090 }
2091
2092 int for_each_ref_in_submodule(const char *submodule, const char *prefix,
2093 each_ref_fn fn, void *cb_data)
2094 {
2095 return do_for_each_ref(get_ref_cache(submodule), prefix, fn, strlen(prefix), 0, cb_data);
2096 }
2097
2098 int for_each_tag_ref(each_ref_fn fn, void *cb_data)
2099 {
2100 return for_each_ref_in("refs/tags/", fn, cb_data);
2101 }
2102
2103 int for_each_tag_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
2104 {
2105 return for_each_ref_in_submodule(submodule, "refs/tags/", fn, cb_data);
2106 }
2107
2108 int for_each_branch_ref(each_ref_fn fn, void *cb_data)
2109 {
2110 return for_each_ref_in("refs/heads/", fn, cb_data);
2111 }
2112
2113 int for_each_branch_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
2114 {
2115 return for_each_ref_in_submodule(submodule, "refs/heads/", fn, cb_data);
2116 }
2117
2118 int for_each_remote_ref(each_ref_fn fn, void *cb_data)
2119 {
2120 return for_each_ref_in("refs/remotes/", fn, cb_data);
2121 }
2122
2123 int for_each_remote_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
2124 {
2125 return for_each_ref_in_submodule(submodule, "refs/remotes/", fn, cb_data);
2126 }
2127
2128 int for_each_replace_ref(each_ref_fn fn, void *cb_data)
2129 {
2130 return do_for_each_ref(&ref_cache, "refs/replace/", fn, 13, 0, cb_data);
2131 }
2132
2133 int head_ref_namespaced(each_ref_fn fn, void *cb_data)
2134 {
2135 struct strbuf buf = STRBUF_INIT;
2136 int ret = 0;
2137 struct object_id oid;
2138 int flag;
2139
2140 strbuf_addf(&buf, "%sHEAD", get_git_namespace());
2141 if (!read_ref_full(buf.buf, RESOLVE_REF_READING, oid.hash, &flag))
2142 ret = fn(buf.buf, &oid, flag, cb_data);
2143 strbuf_release(&buf);
2144
2145 return ret;
2146 }
2147
2148 int for_each_namespaced_ref(each_ref_fn fn, void *cb_data)
2149 {
2150 struct strbuf buf = STRBUF_INIT;
2151 int ret;
2152 strbuf_addf(&buf, "%srefs/", get_git_namespace());
2153 ret = do_for_each_ref(&ref_cache, buf.buf, fn, 0, 0, cb_data);
2154 strbuf_release(&buf);
2155 return ret;
2156 }
2157
2158 int for_each_glob_ref_in(each_ref_fn fn, const char *pattern,
2159 const char *prefix, void *cb_data)
2160 {
2161 struct strbuf real_pattern = STRBUF_INIT;
2162 struct ref_filter filter;
2163 int ret;
2164
2165 if (!prefix && !starts_with(pattern, "refs/"))
2166 strbuf_addstr(&real_pattern, "refs/");
2167 else if (prefix)
2168 strbuf_addstr(&real_pattern, prefix);
2169 strbuf_addstr(&real_pattern, pattern);
2170
2171 if (!has_glob_specials(pattern)) {
2172 /* Append implied '/' '*' if not present. */
2173 if (real_pattern.buf[real_pattern.len - 1] != '/')
2174 strbuf_addch(&real_pattern, '/');
2175 /* No need to check for '*', there is none. */
2176 strbuf_addch(&real_pattern, '*');
2177 }
2178
2179 filter.pattern = real_pattern.buf;
2180 filter.fn = fn;
2181 filter.cb_data = cb_data;
2182 ret = for_each_ref(filter_refs, &filter);
2183
2184 strbuf_release(&real_pattern);
2185 return ret;
2186 }
2187
2188 int for_each_glob_ref(each_ref_fn fn, const char *pattern, void *cb_data)
2189 {
2190 return for_each_glob_ref_in(fn, pattern, NULL, cb_data);
2191 }
2192
2193 int for_each_rawref(each_ref_fn fn, void *cb_data)
2194 {
2195 return do_for_each_ref(&ref_cache, "", fn, 0,
2196 DO_FOR_EACH_INCLUDE_BROKEN, cb_data);
2197 }
2198
2199 const char *prettify_refname(const char *name)
2200 {
2201 return name + (
2202 starts_with(name, "refs/heads/") ? 11 :
2203 starts_with(name, "refs/tags/") ? 10 :
2204 starts_with(name, "refs/remotes/") ? 13 :
2205 0);
2206 }
2207
2208 static const char *ref_rev_parse_rules[] = {
2209 "%.*s",
2210 "refs/%.*s",
2211 "refs/tags/%.*s",
2212 "refs/heads/%.*s",
2213 "refs/remotes/%.*s",
2214 "refs/remotes/%.*s/HEAD",
2215 NULL
2216 };
2217
2218 int refname_match(const char *abbrev_name, const char *full_name)
2219 {
2220 const char **p;
2221 const int abbrev_name_len = strlen(abbrev_name);
2222
2223 for (p = ref_rev_parse_rules; *p; p++) {
2224 if (!strcmp(full_name, mkpath(*p, abbrev_name_len, abbrev_name))) {
2225 return 1;
2226 }
2227 }
2228
2229 return 0;
2230 }
2231
2232 static void unlock_ref(struct ref_lock *lock)
2233 {
2234 /* Do not free lock->lk -- atexit() still looks at them */
2235 if (lock->lk)
2236 rollback_lock_file(lock->lk);
2237 free(lock->ref_name);
2238 free(lock->orig_ref_name);
2239 free(lock);
2240 }
2241
2242 /*
2243 * Verify that the reference locked by lock has the value old_sha1.
2244 * Fail if the reference doesn't exist and mustexist is set. Return 0
2245 * on success. On error, write an error message to err, set errno, and
2246 * return a negative value.
2247 */
2248 static int verify_lock(struct ref_lock *lock,
2249 const unsigned char *old_sha1, int mustexist,
2250 struct strbuf *err)
2251 {
2252 assert(err);
2253
2254 if (read_ref_full(lock->ref_name,
2255 mustexist ? RESOLVE_REF_READING : 0,
2256 lock->old_oid.hash, NULL)) {
2257 int save_errno = errno;
2258 strbuf_addf(err, "can't verify ref %s", lock->ref_name);
2259 errno = save_errno;
2260 return -1;
2261 }
2262 if (hashcmp(lock->old_oid.hash, old_sha1)) {
2263 strbuf_addf(err, "ref %s is at %s but expected %s",
2264 lock->ref_name,
2265 sha1_to_hex(lock->old_oid.hash),
2266 sha1_to_hex(old_sha1));
2267 errno = EBUSY;
2268 return -1;
2269 }
2270 return 0;
2271 }
2272
2273 static int remove_empty_directories(const char *file)
2274 {
2275 /* we want to create a file but there is a directory there;
2276 * if that is an empty directory (or a directory that contains
2277 * only empty directories), remove them.
2278 */
2279 struct strbuf path;
2280 int result, save_errno;
2281
2282 strbuf_init(&path, 20);
2283 strbuf_addstr(&path, file);
2284
2285 result = remove_dir_recursively(&path, REMOVE_DIR_EMPTY_ONLY);
2286 save_errno = errno;
2287
2288 strbuf_release(&path);
2289 errno = save_errno;
2290
2291 return result;
2292 }
2293
2294 /*
2295 * *string and *len will only be substituted, and *string returned (for
2296 * later free()ing) if the string passed in is a magic short-hand form
2297 * to name a branch.
2298 */
2299 static char *substitute_branch_name(const char **string, int *len)
2300 {
2301 struct strbuf buf = STRBUF_INIT;
2302 int ret = interpret_branch_name(*string, *len, &buf);
2303
2304 if (ret == *len) {
2305 size_t size;
2306 *string = strbuf_detach(&buf, &size);
2307 *len = size;
2308 return (char *)*string;
2309 }
2310
2311 return NULL;
2312 }
2313
2314 int dwim_ref(const char *str, int len, unsigned char *sha1, char **ref)
2315 {
2316 char *last_branch = substitute_branch_name(&str, &len);
2317 const char **p, *r;
2318 int refs_found = 0;
2319
2320 *ref = NULL;
2321 for (p = ref_rev_parse_rules; *p; p++) {
2322 char fullref[PATH_MAX];
2323 unsigned char sha1_from_ref[20];
2324 unsigned char *this_result;
2325 int flag;
2326
2327 this_result = refs_found ? sha1_from_ref : sha1;
2328 mksnpath(fullref, sizeof(fullref), *p, len, str);
2329 r = resolve_ref_unsafe(fullref, RESOLVE_REF_READING,
2330 this_result, &flag);
2331 if (r) {
2332 if (!refs_found++)
2333 *ref = xstrdup(r);
2334 if (!warn_ambiguous_refs)
2335 break;
2336 } else if ((flag & REF_ISSYMREF) && strcmp(fullref, "HEAD")) {
2337 warning("ignoring dangling symref %s.", fullref);
2338 } else if ((flag & REF_ISBROKEN) && strchr(fullref, '/')) {
2339 warning("ignoring broken ref %s.", fullref);
2340 }
2341 }
2342 free(last_branch);
2343 return refs_found;
2344 }
2345
2346 int dwim_log(const char *str, int len, unsigned char *sha1, char **log)
2347 {
2348 char *last_branch = substitute_branch_name(&str, &len);
2349 const char **p;
2350 int logs_found = 0;
2351
2352 *log = NULL;
2353 for (p = ref_rev_parse_rules; *p; p++) {
2354 unsigned char hash[20];
2355 char path[PATH_MAX];
2356 const char *ref, *it;
2357
2358 mksnpath(path, sizeof(path), *p, len, str);
2359 ref = resolve_ref_unsafe(path, RESOLVE_REF_READING,
2360 hash, NULL);
2361 if (!ref)
2362 continue;
2363 if (reflog_exists(path))
2364 it = path;
2365 else if (strcmp(ref, path) && reflog_exists(ref))
2366 it = ref;
2367 else
2368 continue;
2369 if (!logs_found++) {
2370 *log = xstrdup(it);
2371 hashcpy(sha1, hash);
2372 }
2373 if (!warn_ambiguous_refs)
2374 break;
2375 }
2376 free(last_branch);
2377 return logs_found;
2378 }
2379
2380 /*
2381 * Locks a ref returning the lock on success and NULL on failure.
2382 * On failure errno is set to something meaningful.
2383 */
2384 static struct ref_lock *lock_ref_sha1_basic(const char *refname,
2385 const unsigned char *old_sha1,
2386 const struct string_list *extras,
2387 const struct string_list *skip,
2388 unsigned int flags, int *type_p,
2389 struct strbuf *err)
2390 {
2391 const char *ref_file;
2392 const char *orig_refname = refname;
2393 struct ref_lock *lock;
2394 int last_errno = 0;
2395 int type, lflags;
2396 int mustexist = (old_sha1 && !is_null_sha1(old_sha1));
2397 int resolve_flags = 0;
2398 int attempts_remaining = 3;
2399
2400 assert(err);
2401
2402 lock = xcalloc(1, sizeof(struct ref_lock));
2403
2404 if (mustexist)
2405 resolve_flags |= RESOLVE_REF_READING;
2406 if (flags & REF_DELETING) {
2407 resolve_flags |= RESOLVE_REF_ALLOW_BAD_NAME;
2408 if (flags & REF_NODEREF)
2409 resolve_flags |= RESOLVE_REF_NO_RECURSE;
2410 }
2411
2412 refname = resolve_ref_unsafe(refname, resolve_flags,
2413 lock->old_oid.hash, &type);
2414 if (!refname && errno == EISDIR) {
2415 /* we are trying to lock foo but we used to
2416 * have foo/bar which now does not exist;
2417 * it is normal for the empty directory 'foo'
2418 * to remain.
2419 */
2420 ref_file = git_path("%s", orig_refname);
2421 if (remove_empty_directories(ref_file)) {
2422 last_errno = errno;
2423
2424 if (!verify_refname_available(orig_refname, extras, skip,
2425 get_loose_refs(&ref_cache), err))
2426 strbuf_addf(err, "there are still refs under '%s'",
2427 orig_refname);
2428
2429 goto error_return;
2430 }
2431 refname = resolve_ref_unsafe(orig_refname, resolve_flags,
2432 lock->old_oid.hash, &type);
2433 }
2434 if (type_p)
2435 *type_p = type;
2436 if (!refname) {
2437 last_errno = errno;
2438 if (last_errno != ENOTDIR ||
2439 !verify_refname_available(orig_refname, extras, skip,
2440 get_loose_refs(&ref_cache), err))
2441 strbuf_addf(err, "unable to resolve reference %s: %s",
2442 orig_refname, strerror(last_errno));
2443
2444 goto error_return;
2445 }
2446 /*
2447 * If the ref did not exist and we are creating it, make sure
2448 * there is no existing packed ref whose name begins with our
2449 * refname, nor a packed ref whose name is a proper prefix of
2450 * our refname.
2451 */
2452 if (is_null_oid(&lock->old_oid) &&
2453 verify_refname_available(refname, extras, skip,
2454 get_packed_refs(&ref_cache), err)) {
2455 last_errno = ENOTDIR;
2456 goto error_return;
2457 }
2458
2459 lock->lk = xcalloc(1, sizeof(struct lock_file));
2460
2461 lflags = 0;
2462 if (flags & REF_NODEREF) {
2463 refname = orig_refname;
2464 lflags |= LOCK_NO_DEREF;
2465 }
2466 lock->ref_name = xstrdup(refname);
2467 lock->orig_ref_name = xstrdup(orig_refname);
2468 ref_file = git_path("%s", refname);
2469
2470 retry:
2471 switch (safe_create_leading_directories_const(ref_file)) {
2472 case SCLD_OK:
2473 break; /* success */
2474 case SCLD_VANISHED:
2475 if (--attempts_remaining > 0)
2476 goto retry;
2477 /* fall through */
2478 default:
2479 last_errno = errno;
2480 strbuf_addf(err, "unable to create directory for %s", ref_file);
2481 goto error_return;
2482 }
2483
2484 if (hold_lock_file_for_update(lock->lk, ref_file, lflags) < 0) {
2485 last_errno = errno;
2486 if (errno == ENOENT && --attempts_remaining > 0)
2487 /*
2488 * Maybe somebody just deleted one of the
2489 * directories leading to ref_file. Try
2490 * again:
2491 */
2492 goto retry;
2493 else {
2494 unable_to_lock_message(ref_file, errno, err);
2495 goto error_return;
2496 }
2497 }
2498 if (old_sha1 && verify_lock(lock, old_sha1, mustexist, err)) {
2499 last_errno = errno;
2500 goto error_return;
2501 }
2502 return lock;
2503
2504 error_return:
2505 unlock_ref(lock);
2506 errno = last_errno;
2507 return NULL;
2508 }
2509
2510 /*
2511 * Write an entry to the packed-refs file for the specified refname.
2512 * If peeled is non-NULL, write it as the entry's peeled value.
2513 */
2514 static void write_packed_entry(FILE *fh, char *refname, unsigned char *sha1,
2515 unsigned char *peeled)
2516 {
2517 fprintf_or_die(fh, "%s %s\n", sha1_to_hex(sha1), refname);
2518 if (peeled)
2519 fprintf_or_die(fh, "^%s\n", sha1_to_hex(peeled));
2520 }
2521
2522 /*
2523 * An each_ref_entry_fn that writes the entry to a packed-refs file.
2524 */
2525 static int write_packed_entry_fn(struct ref_entry *entry, void *cb_data)
2526 {
2527 enum peel_status peel_status = peel_entry(entry, 0);
2528
2529 if (peel_status != PEEL_PEELED && peel_status != PEEL_NON_TAG)
2530 error("internal error: %s is not a valid packed reference!",
2531 entry->name);
2532 write_packed_entry(cb_data, entry->name, entry->u.value.oid.hash,
2533 peel_status == PEEL_PEELED ?
2534 entry->u.value.peeled.hash : NULL);
2535 return 0;
2536 }
2537
2538 /* This should return a meaningful errno on failure */
2539 int lock_packed_refs(int flags)
2540 {
2541 static int timeout_configured = 0;
2542 static int timeout_value = 1000;
2543
2544 struct packed_ref_cache *packed_ref_cache;
2545
2546 if (!timeout_configured) {
2547 git_config_get_int("core.packedrefstimeout", &timeout_value);
2548 timeout_configured = 1;
2549 }
2550
2551 if (hold_lock_file_for_update_timeout(
2552 &packlock, git_path("packed-refs"),
2553 flags, timeout_value) < 0)
2554 return -1;
2555 /*
2556 * Get the current packed-refs while holding the lock. If the
2557 * packed-refs file has been modified since we last read it,
2558 * this will automatically invalidate the cache and re-read
2559 * the packed-refs file.
2560 */
2561 packed_ref_cache = get_packed_ref_cache(&ref_cache);
2562 packed_ref_cache->lock = &packlock;
2563 /* Increment the reference count to prevent it from being freed: */
2564 acquire_packed_ref_cache(packed_ref_cache);
2565 return 0;
2566 }
2567
2568 /*
2569 * Commit the packed refs changes.
2570 * On error we must make sure that errno contains a meaningful value.
2571 */
2572 int commit_packed_refs(void)
2573 {
2574 struct packed_ref_cache *packed_ref_cache =
2575 get_packed_ref_cache(&ref_cache);
2576 int error = 0;
2577 int save_errno = 0;
2578 FILE *out;
2579
2580 if (!packed_ref_cache->lock)
2581 die("internal error: packed-refs not locked");
2582
2583 out = fdopen_lock_file(packed_ref_cache->lock, "w");
2584 if (!out)
2585 die_errno("unable to fdopen packed-refs descriptor");
2586
2587 fprintf_or_die(out, "%s", PACKED_REFS_HEADER);
2588 do_for_each_entry_in_dir(get_packed_ref_dir(packed_ref_cache),
2589 0, write_packed_entry_fn, out);
2590
2591 if (commit_lock_file(packed_ref_cache->lock)) {
2592 save_errno = errno;
2593 error = -1;
2594 }
2595 packed_ref_cache->lock = NULL;
2596 release_packed_ref_cache(packed_ref_cache);
2597 errno = save_errno;
2598 return error;
2599 }
2600
2601 void rollback_packed_refs(void)
2602 {
2603 struct packed_ref_cache *packed_ref_cache =
2604 get_packed_ref_cache(&ref_cache);
2605
2606 if (!packed_ref_cache->lock)
2607 die("internal error: packed-refs not locked");
2608 rollback_lock_file(packed_ref_cache->lock);
2609 packed_ref_cache->lock = NULL;
2610 release_packed_ref_cache(packed_ref_cache);
2611 clear_packed_ref_cache(&ref_cache);
2612 }
2613
2614 struct ref_to_prune {
2615 struct ref_to_prune *next;
2616 unsigned char sha1[20];
2617 char name[FLEX_ARRAY];
2618 };
2619
2620 struct pack_refs_cb_data {
2621 unsigned int flags;
2622 struct ref_dir *packed_refs;
2623 struct ref_to_prune *ref_to_prune;
2624 };
2625
2626 /*
2627 * An each_ref_entry_fn that is run over loose references only. If
2628 * the loose reference can be packed, add an entry in the packed ref
2629 * cache. If the reference should be pruned, also add it to
2630 * ref_to_prune in the pack_refs_cb_data.
2631 */
2632 static int pack_if_possible_fn(struct ref_entry *entry, void *cb_data)
2633 {
2634 struct pack_refs_cb_data *cb = cb_data;
2635 enum peel_status peel_status;
2636 struct ref_entry *packed_entry;
2637 int is_tag_ref = starts_with(entry->name, "refs/tags/");
2638
2639 /* ALWAYS pack tags */
2640 if (!(cb->flags & PACK_REFS_ALL) && !is_tag_ref)
2641 return 0;
2642
2643 /* Do not pack symbolic or broken refs: */
2644 if ((entry->flag & REF_ISSYMREF) || !ref_resolves_to_object(entry))
2645 return 0;
2646
2647 /* Add a packed ref cache entry equivalent to the loose entry. */
2648 peel_status = peel_entry(entry, 1);
2649 if (peel_status != PEEL_PEELED && peel_status != PEEL_NON_TAG)
2650 die("internal error peeling reference %s (%s)",
2651 entry->name, oid_to_hex(&entry->u.value.oid));
2652 packed_entry = find_ref(cb->packed_refs, entry->name);
2653 if (packed_entry) {
2654 /* Overwrite existing packed entry with info from loose entry */
2655 packed_entry->flag = REF_ISPACKED | REF_KNOWS_PEELED;
2656 oidcpy(&packed_entry->u.value.oid, &entry->u.value.oid);
2657 } else {
2658 packed_entry = create_ref_entry(entry->name, entry->u.value.oid.hash,
2659 REF_ISPACKED | REF_KNOWS_PEELED, 0);
2660 add_ref(cb->packed_refs, packed_entry);
2661 }
2662 oidcpy(&packed_entry->u.value.peeled, &entry->u.value.peeled);
2663
2664 /* Schedule the loose reference for pruning if requested. */
2665 if ((cb->flags & PACK_REFS_PRUNE)) {
2666 int namelen = strlen(entry->name) + 1;
2667 struct ref_to_prune *n = xcalloc(1, sizeof(*n) + namelen);
2668 hashcpy(n->sha1, entry->u.value.oid.hash);
2669 strcpy(n->name, entry->name);
2670 n->next = cb->ref_to_prune;
2671 cb->ref_to_prune = n;
2672 }
2673 return 0;
2674 }
2675
2676 /*
2677 * Remove empty parents, but spare refs/ and immediate subdirs.
2678 * Note: munges *name.
2679 */
2680 static void try_remove_empty_parents(char *name)
2681 {
2682 char *p, *q;
2683 int i;
2684 p = name;
2685 for (i = 0; i < 2; i++) { /* refs/{heads,tags,...}/ */
2686 while (*p && *p != '/')
2687 p++;
2688 /* tolerate duplicate slashes; see check_refname_format() */
2689 while (*p == '/')
2690 p++;
2691 }
2692 for (q = p; *q; q++)
2693 ;
2694 while (1) {
2695 while (q > p && *q != '/')
2696 q--;
2697 while (q > p && *(q-1) == '/')
2698 q--;
2699 if (q == p)
2700 break;
2701 *q = '\0';
2702 if (rmdir(git_path("%s", name)))
2703 break;
2704 }
2705 }
2706
2707 /* make sure nobody touched the ref, and unlink */
2708 static void prune_ref(struct ref_to_prune *r)
2709 {
2710 struct ref_transaction *transaction;
2711 struct strbuf err = STRBUF_INIT;
2712
2713 if (check_refname_format(r->name, 0))
2714 return;
2715
2716 transaction = ref_transaction_begin(&err);
2717 if (!transaction ||
2718 ref_transaction_delete(transaction, r->name, r->sha1,
2719 REF_ISPRUNING, NULL, &err) ||
2720 ref_transaction_commit(transaction, &err)) {
2721 ref_transaction_free(transaction);
2722 error("%s", err.buf);
2723 strbuf_release(&err);
2724 return;
2725 }
2726 ref_transaction_free(transaction);
2727 strbuf_release(&err);
2728 try_remove_empty_parents(r->name);
2729 }
2730
2731 static void prune_refs(struct ref_to_prune *r)
2732 {
2733 while (r) {
2734 prune_ref(r);
2735 r = r->next;
2736 }
2737 }
2738
2739 int pack_refs(unsigned int flags)
2740 {
2741 struct pack_refs_cb_data cbdata;
2742
2743 memset(&cbdata, 0, sizeof(cbdata));
2744 cbdata.flags = flags;
2745
2746 lock_packed_refs(LOCK_DIE_ON_ERROR);
2747 cbdata.packed_refs = get_packed_refs(&ref_cache);
2748
2749 do_for_each_entry_in_dir(get_loose_refs(&ref_cache), 0,
2750 pack_if_possible_fn, &cbdata);
2751
2752 if (commit_packed_refs())
2753 die_errno("unable to overwrite old ref-pack file");
2754
2755 prune_refs(cbdata.ref_to_prune);
2756 return 0;
2757 }
2758
2759 int repack_without_refs(struct string_list *refnames, struct strbuf *err)
2760 {
2761 struct ref_dir *packed;
2762 struct string_list_item *refname;
2763 int ret, needs_repacking = 0, removed = 0;
2764
2765 assert(err);
2766
2767 /* Look for a packed ref */
2768 for_each_string_list_item(refname, refnames) {
2769 if (get_packed_ref(refname->string)) {
2770 needs_repacking = 1;
2771 break;
2772 }
2773 }
2774
2775 /* Avoid locking if we have nothing to do */
2776 if (!needs_repacking)
2777 return 0; /* no refname exists in packed refs */
2778
2779 if (lock_packed_refs(0)) {
2780 unable_to_lock_message(git_path("packed-refs"), errno, err);
2781 return -1;
2782 }
2783 packed = get_packed_refs(&ref_cache);
2784
2785 /* Remove refnames from the cache */
2786 for_each_string_list_item(refname, refnames)
2787 if (remove_entry(packed, refname->string) != -1)
2788 removed = 1;
2789 if (!removed) {
2790 /*
2791 * All packed entries disappeared while we were
2792 * acquiring the lock.
2793 */
2794 rollback_packed_refs();
2795 return 0;
2796 }
2797
2798 /* Write what remains */
2799 ret = commit_packed_refs();
2800 if (ret)
2801 strbuf_addf(err, "unable to overwrite old ref-pack file: %s",
2802 strerror(errno));
2803 return ret;
2804 }
2805
2806 static int delete_ref_loose(struct ref_lock *lock, int flag, struct strbuf *err)
2807 {
2808 assert(err);
2809
2810 if (!(flag & REF_ISPACKED) || flag & REF_ISSYMREF) {
2811 /*
2812 * loose. The loose file name is the same as the
2813 * lockfile name, minus ".lock":
2814 */
2815 char *loose_filename = get_locked_file_path(lock->lk);
2816 int res = unlink_or_msg(loose_filename, err);
2817 free(loose_filename);
2818 if (res)
2819 return 1;
2820 }
2821 return 0;
2822 }
2823
2824 static int is_per_worktree_ref(const char *refname)
2825 {
2826 return !strcmp(refname, "HEAD");
2827 }
2828
2829 static int is_pseudoref_syntax(const char *refname)
2830 {
2831 const char *c;
2832
2833 for (c = refname; *c; c++) {
2834 if (!isupper(*c) && *c != '-' && *c != '_')
2835 return 0;
2836 }
2837
2838 return 1;
2839 }
2840
2841 enum ref_type ref_type(const char *refname)
2842 {
2843 if (is_per_worktree_ref(refname))
2844 return REF_TYPE_PER_WORKTREE;
2845 if (is_pseudoref_syntax(refname))
2846 return REF_TYPE_PSEUDOREF;
2847 return REF_TYPE_NORMAL;
2848 }
2849
2850 int delete_ref(const char *refname, const unsigned char *sha1, unsigned int flags)
2851 {
2852 struct ref_transaction *transaction;
2853 struct strbuf err = STRBUF_INIT;
2854
2855 transaction = ref_transaction_begin(&err);
2856 if (!transaction ||
2857 ref_transaction_delete(transaction, refname,
2858 (sha1 && !is_null_sha1(sha1)) ? sha1 : NULL,
2859 flags, NULL, &err) ||
2860 ref_transaction_commit(transaction, &err)) {
2861 error("%s", err.buf);
2862 ref_transaction_free(transaction);
2863 strbuf_release(&err);
2864 return 1;
2865 }
2866 ref_transaction_free(transaction);
2867 strbuf_release(&err);
2868 return 0;
2869 }
2870
2871 /*
2872 * People using contrib's git-new-workdir have .git/logs/refs ->
2873 * /some/other/path/.git/logs/refs, and that may live on another device.
2874 *
2875 * IOW, to avoid cross device rename errors, the temporary renamed log must
2876 * live into logs/refs.
2877 */
2878 #define TMP_RENAMED_LOG "logs/refs/.tmp-renamed-log"
2879
2880 static int rename_tmp_log(const char *newrefname)
2881 {
2882 int attempts_remaining = 4;
2883
2884 retry:
2885 switch (safe_create_leading_directories_const(git_path("logs/%s", newrefname))) {
2886 case SCLD_OK:
2887 break; /* success */
2888 case SCLD_VANISHED:
2889 if (--attempts_remaining > 0)
2890 goto retry;
2891 /* fall through */
2892 default:
2893 error("unable to create directory for %s", newrefname);
2894 return -1;
2895 }
2896
2897 if (rename(git_path(TMP_RENAMED_LOG), git_path("logs/%s", newrefname))) {
2898 if ((errno==EISDIR || errno==ENOTDIR) && --attempts_remaining > 0) {
2899 /*
2900 * rename(a, b) when b is an existing
2901 * directory ought to result in ISDIR, but
2902 * Solaris 5.8 gives ENOTDIR. Sheesh.
2903 */
2904 if (remove_empty_directories(git_path("logs/%s", newrefname))) {
2905 error("Directory not empty: logs/%s", newrefname);
2906 return -1;
2907 }
2908 goto retry;
2909 } else if (errno == ENOENT && --attempts_remaining > 0) {
2910 /*
2911 * Maybe another process just deleted one of
2912 * the directories in the path to newrefname.
2913 * Try again from the beginning.
2914 */
2915 goto retry;
2916 } else {
2917 error("unable to move logfile "TMP_RENAMED_LOG" to logs/%s: %s",
2918 newrefname, strerror(errno));
2919 return -1;
2920 }
2921 }
2922 return 0;
2923 }
2924
2925 static int rename_ref_available(const char *oldname, const char *newname)
2926 {
2927 struct string_list skip = STRING_LIST_INIT_NODUP;
2928 struct strbuf err = STRBUF_INIT;
2929 int ret;
2930
2931 string_list_insert(&skip, oldname);
2932 ret = !verify_refname_available(newname, NULL, &skip,
2933 get_packed_refs(&ref_cache), &err)
2934 && !verify_refname_available(newname, NULL, &skip,
2935 get_loose_refs(&ref_cache), &err);
2936 if (!ret)
2937 error("%s", err.buf);
2938
2939 string_list_clear(&skip, 0);
2940 strbuf_release(&err);
2941 return ret;
2942 }
2943
2944 static int write_ref_to_lockfile(struct ref_lock *lock,
2945 const unsigned char *sha1, struct strbuf *err);
2946 static int commit_ref_update(struct ref_lock *lock,
2947 const unsigned char *sha1, const char *logmsg,
2948 int flags, struct strbuf *err);
2949
2950 int rename_ref(const char *oldrefname, const char *newrefname, const char *logmsg)
2951 {
2952 unsigned char sha1[20], orig_sha1[20];
2953 int flag = 0, logmoved = 0;
2954 struct ref_lock *lock;
2955 struct stat loginfo;
2956 int log = !lstat(git_path("logs/%s", oldrefname), &loginfo);
2957 const char *symref = NULL;
2958 struct strbuf err = STRBUF_INIT;
2959
2960 if (log && S_ISLNK(loginfo.st_mode))
2961 return error("reflog for %s is a symlink", oldrefname);
2962
2963 symref = resolve_ref_unsafe(oldrefname, RESOLVE_REF_READING,
2964 orig_sha1, &flag);
2965 if (flag & REF_ISSYMREF)
2966 return error("refname %s is a symbolic ref, renaming it is not supported",
2967 oldrefname);
2968 if (!symref)
2969 return error("refname %s not found", oldrefname);
2970
2971 if (!rename_ref_available(oldrefname, newrefname))
2972 return 1;
2973
2974 if (log && rename(git_path("logs/%s", oldrefname), git_path(TMP_RENAMED_LOG)))
2975 return error("unable to move logfile logs/%s to "TMP_RENAMED_LOG": %s",
2976 oldrefname, strerror(errno));
2977
2978 if (delete_ref(oldrefname, orig_sha1, REF_NODEREF)) {
2979 error("unable to delete old %s", oldrefname);
2980 goto rollback;
2981 }
2982
2983 if (!read_ref_full(newrefname, RESOLVE_REF_READING, sha1, NULL) &&
2984 delete_ref(newrefname, sha1, REF_NODEREF)) {
2985 if (errno==EISDIR) {
2986 if (remove_empty_directories(git_path("%s", newrefname))) {
2987 error("Directory not empty: %s", newrefname);
2988 goto rollback;
2989 }
2990 } else {
2991 error("unable to delete existing %s", newrefname);
2992 goto rollback;
2993 }
2994 }
2995
2996 if (log && rename_tmp_log(newrefname))
2997 goto rollback;
2998
2999 logmoved = log;
3000
3001 lock = lock_ref_sha1_basic(newrefname, NULL, NULL, NULL, 0, NULL, &err);
3002 if (!lock) {
3003 error("unable to rename '%s' to '%s': %s", oldrefname, newrefname, err.buf);
3004 strbuf_release(&err);
3005 goto rollback;
3006 }
3007 hashcpy(lock->old_oid.hash, orig_sha1);
3008
3009 if (write_ref_to_lockfile(lock, orig_sha1, &err) ||
3010 commit_ref_update(lock, orig_sha1, logmsg, 0, &err)) {
3011 error("unable to write current sha1 into %s: %s", newrefname, err.buf);
3012 strbuf_release(&err);
3013 goto rollback;
3014 }
3015
3016 return 0;
3017
3018 rollback:
3019 lock = lock_ref_sha1_basic(oldrefname, NULL, NULL, NULL, 0, NULL, &err);
3020 if (!lock) {
3021 error("unable to lock %s for rollback: %s", oldrefname, err.buf);
3022 strbuf_release(&err);
3023 goto rollbacklog;
3024 }
3025
3026 flag = log_all_ref_updates;
3027 log_all_ref_updates = 0;
3028 if (write_ref_to_lockfile(lock, orig_sha1, &err) ||
3029 commit_ref_update(lock, orig_sha1, NULL, 0, &err)) {
3030 error("unable to write current sha1 into %s: %s", oldrefname, err.buf);
3031 strbuf_release(&err);
3032 }
3033 log_all_ref_updates = flag;
3034
3035 rollbacklog:
3036 if (logmoved && rename(git_path("logs/%s", newrefname), git_path("logs/%s", oldrefname)))
3037 error("unable to restore logfile %s from %s: %s",
3038 oldrefname, newrefname, strerror(errno));
3039 if (!logmoved && log &&
3040 rename(git_path(TMP_RENAMED_LOG), git_path("logs/%s", oldrefname)))
3041 error("unable to restore logfile %s from "TMP_RENAMED_LOG": %s",
3042 oldrefname, strerror(errno));
3043
3044 return 1;
3045 }
3046
3047 static int close_ref(struct ref_lock *lock)
3048 {
3049 if (close_lock_file(lock->lk))
3050 return -1;
3051 return 0;
3052 }
3053
3054 static int commit_ref(struct ref_lock *lock)
3055 {
3056 if (commit_lock_file(lock->lk))
3057 return -1;
3058 return 0;
3059 }
3060
3061 /*
3062 * copy the reflog message msg to buf, which has been allocated sufficiently
3063 * large, while cleaning up the whitespaces. Especially, convert LF to space,
3064 * because reflog file is one line per entry.
3065 */
3066 static int copy_msg(char *buf, const char *msg)
3067 {
3068 char *cp = buf;
3069 char c;
3070 int wasspace = 1;
3071
3072 *cp++ = '\t';
3073 while ((c = *msg++)) {
3074 if (wasspace && isspace(c))
3075 continue;
3076 wasspace = isspace(c);
3077 if (wasspace)
3078 c = ' ';
3079 *cp++ = c;
3080 }
3081 while (buf < cp && isspace(cp[-1]))
3082 cp--;
3083 *cp++ = '\n';
3084 return cp - buf;
3085 }
3086
3087 static int should_autocreate_reflog(const char *refname)
3088 {
3089 if (!log_all_ref_updates)
3090 return 0;
3091 return starts_with(refname, "refs/heads/") ||
3092 starts_with(refname, "refs/remotes/") ||
3093 starts_with(refname, "refs/notes/") ||
3094 !strcmp(refname, "HEAD");
3095 }
3096
3097 /*
3098 * Create a reflog for a ref. If force_create = 0, the reflog will
3099 * only be created for certain refs (those for which
3100 * should_autocreate_reflog returns non-zero. Otherwise, create it
3101 * regardless of the ref name. Fill in *err and return -1 on failure.
3102 */
3103 static int log_ref_setup(const char *refname, struct strbuf *sb_logfile, struct strbuf *err, int force_create)
3104 {
3105 int logfd, oflags = O_APPEND | O_WRONLY;
3106 char *logfile;
3107
3108 strbuf_git_path(sb_logfile, "logs/%s", refname);
3109 logfile = sb_logfile->buf;
3110 /* make sure the rest of the function can't change "logfile" */
3111 sb_logfile = NULL;
3112 if (force_create || should_autocreate_reflog(refname)) {
3113 if (safe_create_leading_directories(logfile) < 0) {
3114 strbuf_addf(err, "unable to create directory for %s: "
3115 "%s", logfile, strerror(errno));
3116 return -1;
3117 }
3118 oflags |= O_CREAT;
3119 }
3120
3121 logfd = open(logfile, oflags, 0666);
3122 if (logfd < 0) {
3123 if (!(oflags & O_CREAT) && (errno == ENOENT || errno == EISDIR))
3124 return 0;
3125
3126 if (errno == EISDIR) {
3127 if (remove_empty_directories(logfile)) {
3128 strbuf_addf(err, "There are still logs under "
3129 "'%s'", logfile);
3130 return -1;
3131 }
3132 logfd = open(logfile, oflags, 0666);
3133 }
3134
3135 if (logfd < 0) {
3136 strbuf_addf(err, "unable to append to %s: %s",
3137 logfile, strerror(errno));
3138 return -1;
3139 }
3140 }
3141
3142 adjust_shared_perm(logfile);
3143 close(logfd);
3144 return 0;
3145 }
3146
3147
3148 int safe_create_reflog(const char *refname, int force_create, struct strbuf *err)
3149 {
3150 int ret;
3151 struct strbuf sb = STRBUF_INIT;
3152
3153 ret = log_ref_setup(refname, &sb, err, force_create);
3154 strbuf_release(&sb);
3155 return ret;
3156 }
3157
3158 static int log_ref_write_fd(int fd, const unsigned char *old_sha1,
3159 const unsigned char *new_sha1,
3160 const char *committer, const char *msg)
3161 {
3162 int msglen, written;
3163 unsigned maxlen, len;
3164 char *logrec;
3165
3166 msglen = msg ? strlen(msg) : 0;
3167 maxlen = strlen(committer) + msglen + 100;
3168 logrec = xmalloc(maxlen);
3169 len = sprintf(logrec, "%s %s %s\n",
3170 sha1_to_hex(old_sha1),
3171 sha1_to_hex(new_sha1),
3172 committer);
3173 if (msglen)
3174 len += copy_msg(logrec + len - 1, msg) - 1;
3175
3176 written = len <= maxlen ? write_in_full(fd, logrec, len) : -1;
3177 free(logrec);
3178 if (written != len)
3179 return -1;
3180
3181 return 0;
3182 }
3183
3184 static int log_ref_write_1(const char *refname, const unsigned char *old_sha1,
3185 const unsigned char *new_sha1, const char *msg,
3186 struct strbuf *sb_log_file, int flags,
3187 struct strbuf *err)
3188 {
3189 int logfd, result, oflags = O_APPEND | O_WRONLY;
3190 char *log_file;
3191
3192 if (log_all_ref_updates < 0)
3193 log_all_ref_updates = !is_bare_repository();
3194
3195 result = log_ref_setup(refname, sb_log_file, err, flags & REF_FORCE_CREATE_REFLOG);
3196
3197 if (result)
3198 return result;
3199 log_file = sb_log_file->buf;
3200 /* make sure the rest of the function can't change "log_file" */
3201 sb_log_file = NULL;
3202
3203 logfd = open(log_file, oflags);
3204 if (logfd < 0)
3205 return 0;
3206 result = log_ref_write_fd(logfd, old_sha1, new_sha1,
3207 git_committer_info(0), msg);
3208 if (result) {
3209 strbuf_addf(err, "unable to append to %s: %s", log_file,
3210 strerror(errno));
3211 close(logfd);
3212 return -1;
3213 }
3214 if (close(logfd)) {
3215 strbuf_addf(err, "unable to append to %s: %s", log_file,
3216 strerror(errno));
3217 return -1;
3218 }
3219 return 0;
3220 }
3221
3222 static int log_ref_write(const char *refname, const unsigned char *old_sha1,
3223 const unsigned char *new_sha1, const char *msg,
3224 int flags, struct strbuf *err)
3225 {
3226 struct strbuf sb = STRBUF_INIT;
3227 int ret = log_ref_write_1(refname, old_sha1, new_sha1, msg, &sb, flags,
3228 err);
3229 strbuf_release(&sb);
3230 return ret;
3231 }
3232
3233 int is_branch(const char *refname)
3234 {
3235 return !strcmp(refname, "HEAD") || starts_with(refname, "refs/heads/");
3236 }
3237
3238 /*
3239 * Write sha1 into the open lockfile, then close the lockfile. On
3240 * errors, rollback the lockfile, fill in *err and
3241 * return -1.
3242 */
3243 static int write_ref_to_lockfile(struct ref_lock *lock,
3244 const unsigned char *sha1, struct strbuf *err)
3245 {
3246 static char term = '\n';
3247 struct object *o;
3248
3249 o = parse_object(sha1);
3250 if (!o) {
3251 strbuf_addf(err,
3252 "Trying to write ref %s with nonexistent object %s",
3253 lock->ref_name, sha1_to_hex(sha1));
3254 unlock_ref(lock);
3255 return -1;
3256 }
3257 if (o->type != OBJ_COMMIT && is_branch(lock->ref_name)) {
3258 strbuf_addf(err,
3259 "Trying to write non-commit object %s to branch %s",
3260 sha1_to_hex(sha1), lock->ref_name);
3261 unlock_ref(lock);
3262 return -1;
3263 }
3264 if (write_in_full(lock->lk->fd, sha1_to_hex(sha1), 40) != 40 ||
3265 write_in_full(lock->lk->fd, &term, 1) != 1 ||
3266 close_ref(lock) < 0) {
3267 strbuf_addf(err,
3268 "Couldn't write %s", lock->lk->filename.buf);
3269 unlock_ref(lock);
3270 return -1;
3271 }
3272 return 0;
3273 }
3274
3275 /*
3276 * Commit a change to a loose reference that has already been written
3277 * to the loose reference lockfile. Also update the reflogs if
3278 * necessary, using the specified lockmsg (which can be NULL).
3279 */
3280 static int commit_ref_update(struct ref_lock *lock,
3281 const unsigned char *sha1, const char *logmsg,
3282 int flags, struct strbuf *err)
3283 {
3284 clear_loose_ref_cache(&ref_cache);
3285 if (log_ref_write(lock->ref_name, lock->old_oid.hash, sha1, logmsg, flags, err) < 0 ||
3286 (strcmp(lock->ref_name, lock->orig_ref_name) &&
3287 log_ref_write(lock->orig_ref_name, lock->old_oid.hash, sha1, logmsg, flags, err) < 0)) {
3288 char *old_msg = strbuf_detach(err, NULL);
3289 strbuf_addf(err, "Cannot update the ref '%s': %s",
3290 lock->ref_name, old_msg);
3291 free(old_msg);
3292 unlock_ref(lock);
3293 return -1;
3294 }
3295 if (strcmp(lock->orig_ref_name, "HEAD") != 0) {
3296 /*
3297 * Special hack: If a branch is updated directly and HEAD
3298 * points to it (may happen on the remote side of a push
3299 * for example) then logically the HEAD reflog should be
3300 * updated too.
3301 * A generic solution implies reverse symref information,
3302 * but finding all symrefs pointing to the given branch
3303 * would be rather costly for this rare event (the direct
3304 * update of a branch) to be worth it. So let's cheat and
3305 * check with HEAD only which should cover 99% of all usage
3306 * scenarios (even 100% of the default ones).
3307 */
3308 unsigned char head_sha1[20];
3309 int head_flag;
3310 const char *head_ref;
3311 head_ref = resolve_ref_unsafe("HEAD", RESOLVE_REF_READING,
3312 head_sha1, &head_flag);
3313 if (head_ref && (head_flag & REF_ISSYMREF) &&
3314 !strcmp(head_ref, lock->ref_name)) {
3315 struct strbuf log_err = STRBUF_INIT;
3316 if (log_ref_write("HEAD", lock->old_oid.hash, sha1,
3317 logmsg, 0, &log_err)) {
3318 error("%s", log_err.buf);
3319 strbuf_release(&log_err);
3320 }
3321 }
3322 }
3323 if (commit_ref(lock)) {
3324 error("Couldn't set %s", lock->ref_name);
3325 unlock_ref(lock);
3326 return -1;
3327 }
3328
3329 unlock_ref(lock);
3330 return 0;
3331 }
3332
3333 int create_symref(const char *ref_target, const char *refs_heads_master,
3334 const char *logmsg)
3335 {
3336 const char *lockpath;
3337 char ref[1000];
3338 int fd, len, written;
3339 char *git_HEAD = git_pathdup("%s", ref_target);
3340 unsigned char old_sha1[20], new_sha1[20];
3341 struct strbuf err = STRBUF_INIT;
3342
3343 if (logmsg && read_ref(ref_target, old_sha1))
3344 hashclr(old_sha1);
3345
3346 if (safe_create_leading_directories(git_HEAD) < 0)
3347 return error("unable to create directory for %s", git_HEAD);
3348
3349 #ifndef NO_SYMLINK_HEAD
3350 if (prefer_symlink_refs) {
3351 unlink(git_HEAD);
3352 if (!symlink(refs_heads_master, git_HEAD))
3353 goto done;
3354 fprintf(stderr, "no symlink - falling back to symbolic ref\n");
3355 }
3356 #endif
3357
3358 len = snprintf(ref, sizeof(ref), "ref: %s\n", refs_heads_master);
3359 if (sizeof(ref) <= len) {
3360 error("refname too long: %s", refs_heads_master);
3361 goto error_free_return;
3362 }
3363 lockpath = mkpath("%s.lock", git_HEAD);
3364 fd = open(lockpath, O_CREAT | O_EXCL | O_WRONLY, 0666);
3365 if (fd < 0) {
3366 error("Unable to open %s for writing", lockpath);
3367 goto error_free_return;
3368 }
3369 written = write_in_full(fd, ref, len);
3370 if (close(fd) != 0 || written != len) {
3371 error("Unable to write to %s", lockpath);
3372 goto error_unlink_return;
3373 }
3374 if (rename(lockpath, git_HEAD) < 0) {
3375 error("Unable to create %s", git_HEAD);
3376 goto error_unlink_return;
3377 }
3378 if (adjust_shared_perm(git_HEAD)) {
3379 error("Unable to fix permissions on %s", lockpath);
3380 error_unlink_return:
3381 unlink_or_warn(lockpath);
3382 error_free_return:
3383 free(git_HEAD);
3384 return -1;
3385 }
3386
3387 #ifndef NO_SYMLINK_HEAD
3388 done:
3389 #endif
3390 if (logmsg && !read_ref(refs_heads_master, new_sha1) &&
3391 log_ref_write(ref_target, old_sha1, new_sha1, logmsg, 0, &err)) {
3392 error("%s", err.buf);
3393 strbuf_release(&err);
3394 }
3395
3396 free(git_HEAD);
3397 return 0;
3398 }
3399
3400 struct read_ref_at_cb {
3401 const char *refname;
3402 unsigned long at_time;
3403 int cnt;
3404 int reccnt;
3405 unsigned char *sha1;
3406 int found_it;
3407
3408 unsigned char osha1[20];
3409 unsigned char nsha1[20];
3410 int tz;
3411 unsigned long date;
3412 char **msg;
3413 unsigned long *cutoff_time;
3414 int *cutoff_tz;
3415 int *cutoff_cnt;
3416 };
3417
3418 static int read_ref_at_ent(unsigned char *osha1, unsigned char *nsha1,
3419 const char *email, unsigned long timestamp, int tz,
3420 const char *message, void *cb_data)
3421 {
3422 struct read_ref_at_cb *cb = cb_data;
3423
3424 cb->reccnt++;
3425 cb->tz = tz;
3426 cb->date = timestamp;
3427
3428 if (timestamp <= cb->at_time || cb->cnt == 0) {
3429 if (cb->msg)
3430 *cb->msg = xstrdup(message);
3431 if (cb->cutoff_time)
3432 *cb->cutoff_time = timestamp;
3433 if (cb->cutoff_tz)
3434 *cb->cutoff_tz = tz;
3435 if (cb->cutoff_cnt)
3436 *cb->cutoff_cnt = cb->reccnt - 1;
3437 /*
3438 * we have not yet updated cb->[n|o]sha1 so they still
3439 * hold the values for the previous record.
3440 */
3441 if (!is_null_sha1(cb->osha1)) {
3442 hashcpy(cb->sha1, nsha1);
3443 if (hashcmp(cb->osha1, nsha1))
3444 warning("Log for ref %s has gap after %s.",
3445 cb->refname, show_date(cb->date, cb->tz, DATE_RFC2822));
3446 }
3447 else if (cb->date == cb->at_time)
3448 hashcpy(cb->sha1, nsha1);
3449 else if (hashcmp(nsha1, cb->sha1))
3450 warning("Log for ref %s unexpectedly ended on %s.",
3451 cb->refname, show_date(cb->date, cb->tz,
3452 DATE_RFC2822));
3453 hashcpy(cb->osha1, osha1);
3454 hashcpy(cb->nsha1, nsha1);
3455 cb->found_it = 1;
3456 return 1;
3457 }
3458 hashcpy(cb->osha1, osha1);
3459 hashcpy(cb->nsha1, nsha1);
3460 if (cb->cnt > 0)
3461 cb->cnt--;
3462 return 0;
3463 }
3464
3465 static int read_ref_at_ent_oldest(unsigned char *osha1, unsigned char *nsha1,
3466 const char *email, unsigned long timestamp,
3467 int tz, const char *message, void *cb_data)
3468 {
3469 struct read_ref_at_cb *cb = cb_data;
3470
3471 if (cb->msg)
3472 *cb->msg = xstrdup(message);
3473 if (cb->cutoff_time)
3474 *cb->cutoff_time = timestamp;
3475 if (cb->cutoff_tz)
3476 *cb->cutoff_tz = tz;
3477 if (cb->cutoff_cnt)
3478 *cb->cutoff_cnt = cb->reccnt;
3479 hashcpy(cb->sha1, osha1);
3480 if (is_null_sha1(cb->sha1))
3481 hashcpy(cb->sha1, nsha1);
3482 /* We just want the first entry */
3483 return 1;
3484 }
3485
3486 int read_ref_at(const char *refname, unsigned int flags, unsigned long at_time, int cnt,
3487 unsigned char *sha1, char **msg,
3488 unsigned long *cutoff_time, int *cutoff_tz, int *cutoff_cnt)
3489 {
3490 struct read_ref_at_cb cb;
3491
3492 memset(&cb, 0, sizeof(cb));
3493 cb.refname = refname;
3494 cb.at_time = at_time;
3495 cb.cnt = cnt;
3496 cb.msg = msg;
3497 cb.cutoff_time = cutoff_time;
3498 cb.cutoff_tz = cutoff_tz;
3499 cb.cutoff_cnt = cutoff_cnt;
3500 cb.sha1 = sha1;
3501
3502 for_each_reflog_ent_reverse(refname, read_ref_at_ent, &cb);
3503
3504 if (!cb.reccnt) {
3505 if (flags & GET_SHA1_QUIETLY)
3506 exit(128);
3507 else
3508 die("Log for %s is empty.", refname);
3509 }
3510 if (cb.found_it)
3511 return 0;
3512
3513 for_each_reflog_ent(refname, read_ref_at_ent_oldest, &cb);
3514
3515 return 1;
3516 }
3517
3518 int reflog_exists(const char *refname)
3519 {
3520 struct stat st;
3521
3522 return !lstat(git_path("logs/%s", refname), &st) &&
3523 S_ISREG(st.st_mode);
3524 }
3525
3526 int delete_reflog(const char *refname)
3527 {
3528 return remove_path(git_path("logs/%s", refname));
3529 }
3530
3531 static int show_one_reflog_ent(struct strbuf *sb, each_reflog_ent_fn fn, void *cb_data)
3532 {
3533 unsigned char osha1[20], nsha1[20];
3534 char *email_end, *message;
3535 unsigned long timestamp;
3536 int tz;
3537
3538 /* old SP new SP name <email> SP time TAB msg LF */
3539 if (sb->len < 83 || sb->buf[sb->len - 1] != '\n' ||
3540 get_sha1_hex(sb->buf, osha1) || sb->buf[40] != ' ' ||
3541 get_sha1_hex(sb->buf + 41, nsha1) || sb->buf[81] != ' ' ||
3542 !(email_end = strchr(sb->buf + 82, '>')) ||
3543 email_end[1] != ' ' ||
3544 !(timestamp = strtoul(email_end + 2, &message, 10)) ||
3545 !message || message[0] != ' ' ||
3546 (message[1] != '+' && message[1] != '-') ||
3547 !isdigit(message[2]) || !isdigit(message[3]) ||
3548 !isdigit(message[4]) || !isdigit(message[5]))
3549 return 0; /* corrupt? */
3550 email_end[1] = '\0';
3551 tz = strtol(message + 1, NULL, 10);
3552 if (message[6] != '\t')
3553 message += 6;
3554 else
3555 message += 7;
3556 return fn(osha1, nsha1, sb->buf + 82, timestamp, tz, message, cb_data);
3557 }
3558
3559 static char *find_beginning_of_line(char *bob, char *scan)
3560 {
3561 while (bob < scan && *(--scan) != '\n')
3562 ; /* keep scanning backwards */
3563 /*
3564 * Return either beginning of the buffer, or LF at the end of
3565 * the previous line.
3566 */
3567 return scan;
3568 }
3569
3570 int for_each_reflog_ent_reverse(const char *refname, each_reflog_ent_fn fn, void *cb_data)
3571 {
3572 struct strbuf sb = STRBUF_INIT;
3573 FILE *logfp;
3574 long pos;
3575 int ret = 0, at_tail = 1;
3576
3577 logfp = fopen(git_path("logs/%s", refname), "r");
3578 if (!logfp)
3579 return -1;
3580
3581 /* Jump to the end */
3582 if (fseek(logfp, 0, SEEK_END) < 0)
3583 return error("cannot seek back reflog for %s: %s",
3584 refname, strerror(errno));
3585 pos = ftell(logfp);
3586 while (!ret && 0 < pos) {
3587 int cnt;
3588 size_t nread;
3589 char buf[BUFSIZ];
3590 char *endp, *scanp;
3591
3592 /* Fill next block from the end */
3593 cnt = (sizeof(buf) < pos) ? sizeof(buf) : pos;
3594 if (fseek(logfp, pos - cnt, SEEK_SET))
3595 return error("cannot seek back reflog for %s: %s",
3596 refname, strerror(errno));
3597 nread = fread(buf, cnt, 1, logfp);
3598 if (nread != 1)
3599 return error("cannot read %d bytes from reflog for %s: %s",
3600 cnt, refname, strerror(errno));
3601 pos -= cnt;
3602
3603 scanp = endp = buf + cnt;
3604 if (at_tail && scanp[-1] == '\n')
3605 /* Looking at the final LF at the end of the file */
3606 scanp--;
3607 at_tail = 0;
3608
3609 while (buf < scanp) {
3610 /*
3611 * terminating LF of the previous line, or the beginning
3612 * of the buffer.
3613 */
3614 char *bp;
3615
3616 bp = find_beginning_of_line(buf, scanp);
3617
3618 if (*bp == '\n') {
3619 /*
3620 * The newline is the end of the previous line,
3621 * so we know we have complete line starting
3622 * at (bp + 1). Prefix it onto any prior data
3623 * we collected for the line and process it.
3624 */
3625 strbuf_splice(&sb, 0, 0, bp + 1, endp - (bp + 1));
3626 scanp = bp;
3627 endp = bp + 1;
3628 ret = show_one_reflog_ent(&sb, fn, cb_data);
3629 strbuf_reset(&sb);
3630 if (ret)
3631 break;
3632 } else if (!pos) {
3633 /*
3634 * We are at the start of the buffer, and the
3635 * start of the file; there is no previous
3636 * line, and we have everything for this one.
3637 * Process it, and we can end the loop.
3638 */
3639 strbuf_splice(&sb, 0, 0, buf, endp - buf);
3640 ret = show_one_reflog_ent(&sb, fn, cb_data);
3641 strbuf_reset(&sb);
3642 break;
3643 }
3644
3645 if (bp == buf) {
3646 /*
3647 * We are at the start of the buffer, and there
3648 * is more file to read backwards. Which means
3649 * we are in the middle of a line. Note that we
3650 * may get here even if *bp was a newline; that
3651 * just means we are at the exact end of the
3652 * previous line, rather than some spot in the
3653 * middle.
3654 *
3655 * Save away what we have to be combined with
3656 * the data from the next read.
3657 */
3658 strbuf_splice(&sb, 0, 0, buf, endp - buf);
3659 break;
3660 }
3661 }
3662
3663 }
3664 if (!ret && sb.len)
3665 die("BUG: reverse reflog parser had leftover data");
3666
3667 fclose(logfp);
3668 strbuf_release(&sb);
3669 return ret;
3670 }
3671
3672 int for_each_reflog_ent(const char *refname, each_reflog_ent_fn fn, void *cb_data)
3673 {
3674 FILE *logfp;
3675 struct strbuf sb = STRBUF_INIT;
3676 int ret = 0;
3677
3678 logfp = fopen(git_path("logs/%s", refname), "r");
3679 if (!logfp)
3680 return -1;
3681
3682 while (!ret && !strbuf_getwholeline(&sb, logfp, '\n'))
3683 ret = show_one_reflog_ent(&sb, fn, cb_data);
3684 fclose(logfp);
3685 strbuf_release(&sb);
3686 return ret;
3687 }
3688 /*
3689 * Call fn for each reflog in the namespace indicated by name. name
3690 * must be empty or end with '/'. Name will be used as a scratch
3691 * space, but its contents will be restored before return.
3692 */
3693 static int do_for_each_reflog(struct strbuf *name, each_ref_fn fn, void *cb_data)
3694 {
3695 DIR *d = opendir(git_path("logs/%s", name->buf));
3696 int retval = 0;
3697 struct dirent *de;
3698 int oldlen = name->len;
3699
3700 if (!d)
3701 return name->len ? errno : 0;
3702
3703 while ((de = readdir(d)) != NULL) {
3704 struct stat st;
3705
3706 if (de->d_name[0] == '.')
3707 continue;
3708 if (ends_with(de->d_name, ".lock"))
3709 continue;
3710 strbuf_addstr(name, de->d_name);
3711 if (stat(git_path("logs/%s", name->buf), &st) < 0) {
3712 ; /* silently ignore */
3713 } else {
3714 if (S_ISDIR(st.st_mode)) {
3715 strbuf_addch(name, '/');
3716 retval = do_for_each_reflog(name, fn, cb_data);
3717 } else {
3718 struct object_id oid;
3719
3720 if (read_ref_full(name->buf, 0, oid.hash, NULL))
3721 retval = error("bad ref for %s", name->buf);
3722 else
3723 retval = fn(name->buf, &oid, 0, cb_data);
3724 }
3725 if (retval)
3726 break;
3727 }
3728 strbuf_setlen(name, oldlen);
3729 }
3730 closedir(d);
3731 return retval;
3732 }
3733
3734 int for_each_reflog(each_ref_fn fn, void *cb_data)
3735 {
3736 int retval;
3737 struct strbuf name;
3738 strbuf_init(&name, PATH_MAX);
3739 retval = do_for_each_reflog(&name, fn, cb_data);
3740 strbuf_release(&name);
3741 return retval;
3742 }
3743
3744 /**
3745 * Information needed for a single ref update. Set new_sha1 to the new
3746 * value or to null_sha1 to delete the ref. To check the old value
3747 * while the ref is locked, set (flags & REF_HAVE_OLD) and set
3748 * old_sha1 to the old value, or to null_sha1 to ensure the ref does
3749 * not exist before update.
3750 */
3751 struct ref_update {
3752 /*
3753 * If (flags & REF_HAVE_NEW), set the reference to this value:
3754 */
3755 unsigned char new_sha1[20];
3756 /*
3757 * If (flags & REF_HAVE_OLD), check that the reference
3758 * previously had this value:
3759 */
3760 unsigned char old_sha1[20];
3761 /*
3762 * One or more of REF_HAVE_NEW, REF_HAVE_OLD, REF_NODEREF,
3763 * REF_DELETING, and REF_ISPRUNING:
3764 */
3765 unsigned int flags;
3766 struct ref_lock *lock;
3767 int type;
3768 char *msg;
3769 const char refname[FLEX_ARRAY];
3770 };
3771
3772 /*
3773 * Transaction states.
3774 * OPEN: The transaction is in a valid state and can accept new updates.
3775 * An OPEN transaction can be committed.
3776 * CLOSED: A closed transaction is no longer active and no other operations
3777 * than free can be used on it in this state.
3778 * A transaction can either become closed by successfully committing
3779 * an active transaction or if there is a failure while building
3780 * the transaction thus rendering it failed/inactive.
3781 */
3782 enum ref_transaction_state {
3783 REF_TRANSACTION_OPEN = 0,
3784 REF_TRANSACTION_CLOSED = 1
3785 };
3786
3787 /*
3788 * Data structure for holding a reference transaction, which can
3789 * consist of checks and updates to multiple references, carried out
3790 * as atomically as possible. This structure is opaque to callers.
3791 */
3792 struct ref_transaction {
3793 struct ref_update **updates;
3794 size_t alloc;
3795 size_t nr;
3796 enum ref_transaction_state state;
3797 };
3798
3799 struct ref_transaction *ref_transaction_begin(struct strbuf *err)
3800 {
3801 assert(err);
3802
3803 return xcalloc(1, sizeof(struct ref_transaction));
3804 }
3805
3806 void ref_transaction_free(struct ref_transaction *transaction)
3807 {
3808 int i;
3809
3810 if (!transaction)
3811 return;
3812
3813 for (i = 0; i < transaction->nr; i++) {
3814 free(transaction->updates[i]->msg);
3815 free(transaction->updates[i]);
3816 }
3817 free(transaction->updates);
3818 free(transaction);
3819 }
3820
3821 static struct ref_update *add_update(struct ref_transaction *transaction,
3822 const char *refname)
3823 {
3824 size_t len = strlen(refname);
3825 struct ref_update *update = xcalloc(1, sizeof(*update) + len + 1);
3826
3827 strcpy((char *)update->refname, refname);
3828 ALLOC_GROW(transaction->updates, transaction->nr + 1, transaction->alloc);
3829 transaction->updates[transaction->nr++] = update;
3830 return update;
3831 }
3832
3833 int ref_transaction_update(struct ref_transaction *transaction,
3834 const char *refname,
3835 const unsigned char *new_sha1,
3836 const unsigned char *old_sha1,
3837 unsigned int flags, const char *msg,
3838 struct strbuf *err)
3839 {
3840 struct ref_update *update;
3841
3842 assert(err);
3843
3844 if (transaction->state != REF_TRANSACTION_OPEN)
3845 die("BUG: update called for transaction that is not open");
3846
3847 if (new_sha1 && !is_null_sha1(new_sha1) &&
3848 check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
3849 strbuf_addf(err, "refusing to update ref with bad name %s",
3850 refname);
3851 return -1;
3852 }
3853
3854 update = add_update(transaction, refname);
3855 if (new_sha1) {
3856 hashcpy(update->new_sha1, new_sha1);
3857 flags |= REF_HAVE_NEW;
3858 }
3859 if (old_sha1) {
3860 hashcpy(update->old_sha1, old_sha1);
3861 flags |= REF_HAVE_OLD;
3862 }
3863 update->flags = flags;
3864 if (msg)
3865 update->msg = xstrdup(msg);
3866 return 0;
3867 }
3868
3869 int ref_transaction_create(struct ref_transaction *transaction,
3870 const char *refname,
3871 const unsigned char *new_sha1,
3872 unsigned int flags, const char *msg,
3873 struct strbuf *err)
3874 {
3875 if (!new_sha1 || is_null_sha1(new_sha1))
3876 die("BUG: create called without valid new_sha1");
3877 return ref_transaction_update(transaction, refname, new_sha1,
3878 null_sha1, flags, msg, err);
3879 }
3880
3881 int ref_transaction_delete(struct ref_transaction *transaction,
3882 const char *refname,
3883 const unsigned char *old_sha1,
3884 unsigned int flags, const char *msg,
3885 struct strbuf *err)
3886 {
3887 if (old_sha1 && is_null_sha1(old_sha1))
3888 die("BUG: delete called with old_sha1 set to zeros");
3889 return ref_transaction_update(transaction, refname,
3890 null_sha1, old_sha1,
3891 flags, msg, err);
3892 }
3893
3894 int ref_transaction_verify(struct ref_transaction *transaction,
3895 const char *refname,
3896 const unsigned char *old_sha1,
3897 unsigned int flags,
3898 struct strbuf *err)
3899 {
3900 if (!old_sha1)
3901 die("BUG: verify called with old_sha1 set to NULL");
3902 return ref_transaction_update(transaction, refname,
3903 NULL, old_sha1,
3904 flags, NULL, err);
3905 }
3906
3907 int update_ref(const char *msg, const char *refname,
3908 const unsigned char *new_sha1, const unsigned char *old_sha1,
3909 unsigned int flags, enum action_on_err onerr)
3910 {
3911 struct ref_transaction *t;
3912 struct strbuf err = STRBUF_INIT;
3913
3914 t = ref_transaction_begin(&err);
3915 if (!t ||
3916 ref_transaction_update(t, refname, new_sha1, old_sha1,
3917 flags, msg, &err) ||
3918 ref_transaction_commit(t, &err)) {
3919 const char *str = "update_ref failed for ref '%s': %s";
3920
3921 ref_transaction_free(t);
3922 switch (onerr) {
3923 case UPDATE_REFS_MSG_ON_ERR:
3924 error(str, refname, err.buf);
3925 break;
3926 case UPDATE_REFS_DIE_ON_ERR:
3927 die(str, refname, err.buf);
3928 break;
3929 case UPDATE_REFS_QUIET_ON_ERR:
3930 break;
3931 }
3932 strbuf_release(&err);
3933 return 1;
3934 }
3935 strbuf_release(&err);
3936 ref_transaction_free(t);
3937 return 0;