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