Merge branch 'ls/p4-doc-markup'
[git/git.git] / refs / files-backend.c
CommitLineData
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1#include "../cache.h"
2#include "../refs.h"
3#include "refs-internal.h"
4#include "../lockfile.h"
5#include "../object.h"
6#include "../dir.h"
7
8struct ref_lock {
9 char *ref_name;
10 char *orig_ref_name;
11 struct lock_file *lk;
12 struct object_id old_oid;
13};
14
15struct ref_entry;
16
17/*
18 * Information used (along with the information in ref_entry) to
19 * describe a single cached reference. This data structure only
20 * occurs embedded in a union in struct ref_entry, and only when
21 * (ref_entry->flag & REF_DIR) is zero.
22 */
23struct ref_value {
24 /*
25 * The name of the object to which this reference resolves
26 * (which may be a tag object). If REF_ISBROKEN, this is
27 * null. If REF_ISSYMREF, then this is the name of the object
28 * referred to by the last reference in the symlink chain.
29 */
30 struct object_id oid;
31
32 /*
33 * If REF_KNOWS_PEELED, then this field holds the peeled value
34 * of this reference, or null if the reference is known not to
35 * be peelable. See the documentation for peel_ref() for an
36 * exact definition of "peelable".
37 */
38 struct object_id peeled;
39};
40
41struct ref_cache;
42
43/*
44 * Information used (along with the information in ref_entry) to
45 * describe a level in the hierarchy of references. This data
46 * structure only occurs embedded in a union in struct ref_entry, and
47 * only when (ref_entry.flag & REF_DIR) is set. In that case,
48 * (ref_entry.flag & REF_INCOMPLETE) determines whether the references
49 * in the directory have already been read:
50 *
51 * (ref_entry.flag & REF_INCOMPLETE) unset -- a directory of loose
52 * or packed references, already read.
53 *
54 * (ref_entry.flag & REF_INCOMPLETE) set -- a directory of loose
55 * references that hasn't been read yet (nor has any of its
56 * subdirectories).
57 *
58 * Entries within a directory are stored within a growable array of
59 * pointers to ref_entries (entries, nr, alloc). Entries 0 <= i <
60 * sorted are sorted by their component name in strcmp() order and the
61 * remaining entries are unsorted.
62 *
63 * Loose references are read lazily, one directory at a time. When a
64 * directory of loose references is read, then all of the references
65 * in that directory are stored, and REF_INCOMPLETE stubs are created
66 * for any subdirectories, but the subdirectories themselves are not
67 * read. The reading is triggered by get_ref_dir().
68 */
69struct ref_dir {
70 int nr, alloc;
71
72 /*
73 * Entries with index 0 <= i < sorted are sorted by name. New
74 * entries are appended to the list unsorted, and are sorted
75 * only when required; thus we avoid the need to sort the list
76 * after the addition of every reference.
77 */
78 int sorted;
79
80 /* A pointer to the ref_cache that contains this ref_dir. */
81 struct ref_cache *ref_cache;
82
83 struct ref_entry **entries;
84};
85
86/*
87 * Bit values for ref_entry::flag. REF_ISSYMREF=0x01,
88 * REF_ISPACKED=0x02, REF_ISBROKEN=0x04 and REF_BAD_NAME=0x08 are
89 * public values; see refs.h.
90 */
91
92/*
93 * The field ref_entry->u.value.peeled of this value entry contains
94 * the correct peeled value for the reference, which might be
95 * null_sha1 if the reference is not a tag or if it is broken.
96 */
97#define REF_KNOWS_PEELED 0x10
98
99/* ref_entry represents a directory of references */
100#define REF_DIR 0x20
101
102/*
103 * Entry has not yet been read from disk (used only for REF_DIR
104 * entries representing loose references)
105 */
106#define REF_INCOMPLETE 0x40
107
108/*
109 * A ref_entry represents either a reference or a "subdirectory" of
110 * references.
111 *
112 * Each directory in the reference namespace is represented by a
113 * ref_entry with (flags & REF_DIR) set and containing a subdir member
114 * that holds the entries in that directory that have been read so
115 * far. If (flags & REF_INCOMPLETE) is set, then the directory and
116 * its subdirectories haven't been read yet. REF_INCOMPLETE is only
117 * used for loose reference directories.
118 *
119 * References are represented by a ref_entry with (flags & REF_DIR)
120 * unset and a value member that describes the reference's value. The
121 * flag member is at the ref_entry level, but it is also needed to
122 * interpret the contents of the value field (in other words, a
123 * ref_value object is not very much use without the enclosing
124 * ref_entry).
125 *
126 * Reference names cannot end with slash and directories' names are
127 * always stored with a trailing slash (except for the top-level
128 * directory, which is always denoted by ""). This has two nice
129 * consequences: (1) when the entries in each subdir are sorted
130 * lexicographically by name (as they usually are), the references in
131 * a whole tree can be generated in lexicographic order by traversing
132 * the tree in left-to-right, depth-first order; (2) the names of
133 * references and subdirectories cannot conflict, and therefore the
134 * presence of an empty subdirectory does not block the creation of a
135 * similarly-named reference. (The fact that reference names with the
136 * same leading components can conflict *with each other* is a
137 * separate issue that is regulated by verify_refname_available().)
138 *
139 * Please note that the name field contains the fully-qualified
140 * reference (or subdirectory) name. Space could be saved by only
141 * storing the relative names. But that would require the full names
142 * to be generated on the fly when iterating in do_for_each_ref(), and
143 * would break callback functions, who have always been able to assume
144 * that the name strings that they are passed will not be freed during
145 * the iteration.
146 */
147struct ref_entry {
148 unsigned char flag; /* ISSYMREF? ISPACKED? */
149 union {
150 struct ref_value value; /* if not (flags&REF_DIR) */
151 struct ref_dir subdir; /* if (flags&REF_DIR) */
152 } u;
153 /*
154 * The full name of the reference (e.g., "refs/heads/master")
155 * or the full name of the directory with a trailing slash
156 * (e.g., "refs/heads/"):
157 */
158 char name[FLEX_ARRAY];
159};
160
161static void read_loose_refs(const char *dirname, struct ref_dir *dir);
162static int search_ref_dir(struct ref_dir *dir, const char *refname, size_t len);
163static struct ref_entry *create_dir_entry(struct ref_cache *ref_cache,
164 const char *dirname, size_t len,
165 int incomplete);
166static void add_entry_to_dir(struct ref_dir *dir, struct ref_entry *entry);
167
168static struct ref_dir *get_ref_dir(struct ref_entry *entry)
169{
170 struct ref_dir *dir;
171 assert(entry->flag & REF_DIR);
172 dir = &entry->u.subdir;
173 if (entry->flag & REF_INCOMPLETE) {
174 read_loose_refs(entry->name, dir);
175
176 /*
177 * Manually add refs/bisect, which, being
178 * per-worktree, might not appear in the directory
179 * listing for refs/ in the main repo.
180 */
181 if (!strcmp(entry->name, "refs/")) {
182 int pos = search_ref_dir(dir, "refs/bisect/", 12);
183 if (pos < 0) {
184 struct ref_entry *child_entry;
185 child_entry = create_dir_entry(dir->ref_cache,
186 "refs/bisect/",
187 12, 1);
188 add_entry_to_dir(dir, child_entry);
189 read_loose_refs("refs/bisect",
190 &child_entry->u.subdir);
191 }
192 }
193 entry->flag &= ~REF_INCOMPLETE;
194 }
195 return dir;
196}
197
198static struct ref_entry *create_ref_entry(const char *refname,
199 const unsigned char *sha1, int flag,
200 int check_name)
201{
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202 struct ref_entry *ref;
203
204 if (check_name &&
205 check_refname_format(refname, REFNAME_ALLOW_ONELEVEL))
206 die("Reference has invalid format: '%s'", refname);
96ffc06f 207 FLEX_ALLOC_STR(ref, name, refname);
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208 hashcpy(ref->u.value.oid.hash, sha1);
209 oidclr(&ref->u.value.peeled);
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210 ref->flag = flag;
211 return ref;
212}
213
214static void clear_ref_dir(struct ref_dir *dir);
215
216static void free_ref_entry(struct ref_entry *entry)
217{
218 if (entry->flag & REF_DIR) {
219 /*
220 * Do not use get_ref_dir() here, as that might
221 * trigger the reading of loose refs.
222 */
223 clear_ref_dir(&entry->u.subdir);
224 }
225 free(entry);
226}
227
228/*
229 * Add a ref_entry to the end of dir (unsorted). Entry is always
230 * stored directly in dir; no recursion into subdirectories is
231 * done.
232 */
233static void add_entry_to_dir(struct ref_dir *dir, struct ref_entry *entry)
234{
235 ALLOC_GROW(dir->entries, dir->nr + 1, dir->alloc);
236 dir->entries[dir->nr++] = entry;
237 /* optimize for the case that entries are added in order */
238 if (dir->nr == 1 ||
239 (dir->nr == dir->sorted + 1 &&
240 strcmp(dir->entries[dir->nr - 2]->name,
241 dir->entries[dir->nr - 1]->name) < 0))
242 dir->sorted = dir->nr;
243}
244
245/*
246 * Clear and free all entries in dir, recursively.
247 */
248static void clear_ref_dir(struct ref_dir *dir)
249{
250 int i;
251 for (i = 0; i < dir->nr; i++)
252 free_ref_entry(dir->entries[i]);
253 free(dir->entries);
254 dir->sorted = dir->nr = dir->alloc = 0;
255 dir->entries = NULL;
256}
257
258/*
259 * Create a struct ref_entry object for the specified dirname.
260 * dirname is the name of the directory with a trailing slash (e.g.,
261 * "refs/heads/") or "" for the top-level directory.
262 */
263static struct ref_entry *create_dir_entry(struct ref_cache *ref_cache,
264 const char *dirname, size_t len,
265 int incomplete)
266{
267 struct ref_entry *direntry;
96ffc06f 268 FLEX_ALLOC_MEM(direntry, name, dirname, len);
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269 direntry->u.subdir.ref_cache = ref_cache;
270 direntry->flag = REF_DIR | (incomplete ? REF_INCOMPLETE : 0);
271 return direntry;
272}
273
274static int ref_entry_cmp(const void *a, const void *b)
275{
276 struct ref_entry *one = *(struct ref_entry **)a;
277 struct ref_entry *two = *(struct ref_entry **)b;
278 return strcmp(one->name, two->name);
279}
280
281static void sort_ref_dir(struct ref_dir *dir);
282
283struct string_slice {
284 size_t len;
285 const char *str;
286};
287
288static int ref_entry_cmp_sslice(const void *key_, const void *ent_)
289{
290 const struct string_slice *key = key_;
291 const struct ref_entry *ent = *(const struct ref_entry * const *)ent_;
292 int cmp = strncmp(key->str, ent->name, key->len);
293 if (cmp)
294 return cmp;
295 return '\0' - (unsigned char)ent->name[key->len];
296}
297
298/*
299 * Return the index of the entry with the given refname from the
300 * ref_dir (non-recursively), sorting dir if necessary. Return -1 if
301 * no such entry is found. dir must already be complete.
302 */
303static int search_ref_dir(struct ref_dir *dir, const char *refname, size_t len)
304{
305 struct ref_entry **r;
306 struct string_slice key;
307
308 if (refname == NULL || !dir->nr)
309 return -1;
310
311 sort_ref_dir(dir);
312 key.len = len;
313 key.str = refname;
314 r = bsearch(&key, dir->entries, dir->nr, sizeof(*dir->entries),
315 ref_entry_cmp_sslice);
316
317 if (r == NULL)
318 return -1;
319
320 return r - dir->entries;
321}
322
323/*
324 * Search for a directory entry directly within dir (without
325 * recursing). Sort dir if necessary. subdirname must be a directory
326 * name (i.e., end in '/'). If mkdir is set, then create the
327 * directory if it is missing; otherwise, return NULL if the desired
328 * directory cannot be found. dir must already be complete.
329 */
330static struct ref_dir *search_for_subdir(struct ref_dir *dir,
331 const char *subdirname, size_t len,
332 int mkdir)
333{
334 int entry_index = search_ref_dir(dir, subdirname, len);
335 struct ref_entry *entry;
336 if (entry_index == -1) {
337 if (!mkdir)
338 return NULL;
339 /*
340 * Since dir is complete, the absence of a subdir
341 * means that the subdir really doesn't exist;
342 * therefore, create an empty record for it but mark
343 * the record complete.
344 */
345 entry = create_dir_entry(dir->ref_cache, subdirname, len, 0);
346 add_entry_to_dir(dir, entry);
347 } else {
348 entry = dir->entries[entry_index];
349 }
350 return get_ref_dir(entry);
351}
352
353/*
354 * If refname is a reference name, find the ref_dir within the dir
355 * tree that should hold refname. If refname is a directory name
356 * (i.e., ends in '/'), then return that ref_dir itself. dir must
357 * represent the top-level directory and must already be complete.
358 * Sort ref_dirs and recurse into subdirectories as necessary. If
359 * mkdir is set, then create any missing directories; otherwise,
360 * return NULL if the desired directory cannot be found.
361 */
362static struct ref_dir *find_containing_dir(struct ref_dir *dir,
363 const char *refname, int mkdir)
364{
365 const char *slash;
366 for (slash = strchr(refname, '/'); slash; slash = strchr(slash + 1, '/')) {
367 size_t dirnamelen = slash - refname + 1;
368 struct ref_dir *subdir;
369 subdir = search_for_subdir(dir, refname, dirnamelen, mkdir);
370 if (!subdir) {
371 dir = NULL;
372 break;
373 }
374 dir = subdir;
375 }
376
377 return dir;
378}
379
380/*
381 * Find the value entry with the given name in dir, sorting ref_dirs
382 * and recursing into subdirectories as necessary. If the name is not
383 * found or it corresponds to a directory entry, return NULL.
384 */
385static struct ref_entry *find_ref(struct ref_dir *dir, const char *refname)
386{
387 int entry_index;
388 struct ref_entry *entry;
389 dir = find_containing_dir(dir, refname, 0);
390 if (!dir)
391 return NULL;
392 entry_index = search_ref_dir(dir, refname, strlen(refname));
393 if (entry_index == -1)
394 return NULL;
395 entry = dir->entries[entry_index];
396 return (entry->flag & REF_DIR) ? NULL : entry;
397}
398
399/*
400 * Remove the entry with the given name from dir, recursing into
401 * subdirectories as necessary. If refname is the name of a directory
402 * (i.e., ends with '/'), then remove the directory and its contents.
403 * If the removal was successful, return the number of entries
404 * remaining in the directory entry that contained the deleted entry.
405 * If the name was not found, return -1. Please note that this
406 * function only deletes the entry from the cache; it does not delete
407 * it from the filesystem or ensure that other cache entries (which
408 * might be symbolic references to the removed entry) are updated.
409 * Nor does it remove any containing dir entries that might be made
410 * empty by the removal. dir must represent the top-level directory
411 * and must already be complete.
412 */
413static int remove_entry(struct ref_dir *dir, const char *refname)
414{
415 int refname_len = strlen(refname);
416 int entry_index;
417 struct ref_entry *entry;
418 int is_dir = refname[refname_len - 1] == '/';
419 if (is_dir) {
420 /*
421 * refname represents a reference directory. Remove
422 * the trailing slash; otherwise we will get the
423 * directory *representing* refname rather than the
424 * one *containing* it.
425 */
426 char *dirname = xmemdupz(refname, refname_len - 1);
427 dir = find_containing_dir(dir, dirname, 0);
428 free(dirname);
429 } else {
430 dir = find_containing_dir(dir, refname, 0);
431 }
432 if (!dir)
433 return -1;
434 entry_index = search_ref_dir(dir, refname, refname_len);
435 if (entry_index == -1)
436 return -1;
437 entry = dir->entries[entry_index];
438
439 memmove(&dir->entries[entry_index],
440 &dir->entries[entry_index + 1],
441 (dir->nr - entry_index - 1) * sizeof(*dir->entries)
442 );
443 dir->nr--;
444 if (dir->sorted > entry_index)
445 dir->sorted--;
446 free_ref_entry(entry);
447 return dir->nr;
448}
449
450/*
451 * Add a ref_entry to the ref_dir (unsorted), recursing into
452 * subdirectories as necessary. dir must represent the top-level
453 * directory. Return 0 on success.
454 */
455static int add_ref(struct ref_dir *dir, struct ref_entry *ref)
456{
457 dir = find_containing_dir(dir, ref->name, 1);
458 if (!dir)
459 return -1;
460 add_entry_to_dir(dir, ref);
461 return 0;
462}
463
464/*
465 * Emit a warning and return true iff ref1 and ref2 have the same name
466 * and the same sha1. Die if they have the same name but different
467 * sha1s.
468 */
469static int is_dup_ref(const struct ref_entry *ref1, const struct ref_entry *ref2)
470{
471 if (strcmp(ref1->name, ref2->name))
472 return 0;
473
474 /* Duplicate name; make sure that they don't conflict: */
475
476 if ((ref1->flag & REF_DIR) || (ref2->flag & REF_DIR))
477 /* This is impossible by construction */
478 die("Reference directory conflict: %s", ref1->name);
479
480 if (oidcmp(&ref1->u.value.oid, &ref2->u.value.oid))
481 die("Duplicated ref, and SHA1s don't match: %s", ref1->name);
482
483 warning("Duplicated ref: %s", ref1->name);
484 return 1;
485}
486
487/*
488 * Sort the entries in dir non-recursively (if they are not already
489 * sorted) and remove any duplicate entries.
490 */
491static void sort_ref_dir(struct ref_dir *dir)
492{
493 int i, j;
494 struct ref_entry *last = NULL;
495
496 /*
497 * This check also prevents passing a zero-length array to qsort(),
498 * which is a problem on some platforms.
499 */
500 if (dir->sorted == dir->nr)
501 return;
502
503 qsort(dir->entries, dir->nr, sizeof(*dir->entries), ref_entry_cmp);
504
505 /* Remove any duplicates: */
506 for (i = 0, j = 0; j < dir->nr; j++) {
507 struct ref_entry *entry = dir->entries[j];
508 if (last && is_dup_ref(last, entry))
509 free_ref_entry(entry);
510 else
511 last = dir->entries[i++] = entry;
512 }
513 dir->sorted = dir->nr = i;
514}
515
516/* Include broken references in a do_for_each_ref*() iteration: */
517#define DO_FOR_EACH_INCLUDE_BROKEN 0x01
518
519/*
520 * Return true iff the reference described by entry can be resolved to
521 * an object in the database. Emit a warning if the referred-to
522 * object does not exist.
523 */
524static int ref_resolves_to_object(struct ref_entry *entry)
525{
526 if (entry->flag & REF_ISBROKEN)
527 return 0;
528 if (!has_sha1_file(entry->u.value.oid.hash)) {
529 error("%s does not point to a valid object!", entry->name);
530 return 0;
531 }
532 return 1;
533}
534
535/*
536 * current_ref is a performance hack: when iterating over references
537 * using the for_each_ref*() functions, current_ref is set to the
538 * current reference's entry before calling the callback function. If
539 * the callback function calls peel_ref(), then peel_ref() first
540 * checks whether the reference to be peeled is the current reference
541 * (it usually is) and if so, returns that reference's peeled version
542 * if it is available. This avoids a refname lookup in a common case.
543 */
544static struct ref_entry *current_ref;
545
546typedef int each_ref_entry_fn(struct ref_entry *entry, void *cb_data);
547
548struct ref_entry_cb {
549 const char *base;
550 int trim;
551 int flags;
552 each_ref_fn *fn;
553 void *cb_data;
554};
555
556/*
557 * Handle one reference in a do_for_each_ref*()-style iteration,
558 * calling an each_ref_fn for each entry.
559 */
560static int do_one_ref(struct ref_entry *entry, void *cb_data)
561{
562 struct ref_entry_cb *data = cb_data;
563 struct ref_entry *old_current_ref;
564 int retval;
565
566 if (!starts_with(entry->name, data->base))
567 return 0;
568
569 if (!(data->flags & DO_FOR_EACH_INCLUDE_BROKEN) &&
570 !ref_resolves_to_object(entry))
571 return 0;
572
573 /* Store the old value, in case this is a recursive call: */
574 old_current_ref = current_ref;
575 current_ref = entry;
576 retval = data->fn(entry->name + data->trim, &entry->u.value.oid,
577 entry->flag, data->cb_data);
578 current_ref = old_current_ref;
579 return retval;
580}
581
582/*
583 * Call fn for each reference in dir that has index in the range
584 * offset <= index < dir->nr. Recurse into subdirectories that are in
585 * that index range, sorting them before iterating. This function
586 * does not sort dir itself; it should be sorted beforehand. fn is
587 * called for all references, including broken ones.
588 */
589static int do_for_each_entry_in_dir(struct ref_dir *dir, int offset,
590 each_ref_entry_fn fn, void *cb_data)
591{
592 int i;
593 assert(dir->sorted == dir->nr);
594 for (i = offset; i < dir->nr; i++) {
595 struct ref_entry *entry = dir->entries[i];
596 int retval;
597 if (entry->flag & REF_DIR) {
598 struct ref_dir *subdir = get_ref_dir(entry);
599 sort_ref_dir(subdir);
600 retval = do_for_each_entry_in_dir(subdir, 0, fn, cb_data);
601 } else {
602 retval = fn(entry, cb_data);
603 }
604 if (retval)
605 return retval;
606 }
607 return 0;
608}
609
610/*
611 * Call fn for each reference in the union of dir1 and dir2, in order
612 * by refname. Recurse into subdirectories. If a value entry appears
613 * in both dir1 and dir2, then only process the version that is in
614 * dir2. The input dirs must already be sorted, but subdirs will be
615 * sorted as needed. fn is called for all references, including
616 * broken ones.
617 */
618static int do_for_each_entry_in_dirs(struct ref_dir *dir1,
619 struct ref_dir *dir2,
620 each_ref_entry_fn fn, void *cb_data)
621{
622 int retval;
623 int i1 = 0, i2 = 0;
624
625 assert(dir1->sorted == dir1->nr);
626 assert(dir2->sorted == dir2->nr);
627 while (1) {
628 struct ref_entry *e1, *e2;
629 int cmp;
630 if (i1 == dir1->nr) {
631 return do_for_each_entry_in_dir(dir2, i2, fn, cb_data);
632 }
633 if (i2 == dir2->nr) {
634 return do_for_each_entry_in_dir(dir1, i1, fn, cb_data);
635 }
636 e1 = dir1->entries[i1];
637 e2 = dir2->entries[i2];
638 cmp = strcmp(e1->name, e2->name);
639 if (cmp == 0) {
640 if ((e1->flag & REF_DIR) && (e2->flag & REF_DIR)) {
641 /* Both are directories; descend them in parallel. */
642 struct ref_dir *subdir1 = get_ref_dir(e1);
643 struct ref_dir *subdir2 = get_ref_dir(e2);
644 sort_ref_dir(subdir1);
645 sort_ref_dir(subdir2);
646 retval = do_for_each_entry_in_dirs(
647 subdir1, subdir2, fn, cb_data);
648 i1++;
649 i2++;
650 } else if (!(e1->flag & REF_DIR) && !(e2->flag & REF_DIR)) {
651 /* Both are references; ignore the one from dir1. */
652 retval = fn(e2, cb_data);
653 i1++;
654 i2++;
655 } else {
656 die("conflict between reference and directory: %s",
657 e1->name);
658 }
659 } else {
660 struct ref_entry *e;
661 if (cmp < 0) {
662 e = e1;
663 i1++;
664 } else {
665 e = e2;
666 i2++;
667 }
668 if (e->flag & REF_DIR) {
669 struct ref_dir *subdir = get_ref_dir(e);
670 sort_ref_dir(subdir);
671 retval = do_for_each_entry_in_dir(
672 subdir, 0, fn, cb_data);
673 } else {
674 retval = fn(e, cb_data);
675 }
676 }
677 if (retval)
678 return retval;
679 }
680}
681
682/*
683 * Load all of the refs from the dir into our in-memory cache. The hard work
684 * of loading loose refs is done by get_ref_dir(), so we just need to recurse
685 * through all of the sub-directories. We do not even need to care about
686 * sorting, as traversal order does not matter to us.
687 */
688static void prime_ref_dir(struct ref_dir *dir)
689{
690 int i;
691 for (i = 0; i < dir->nr; i++) {
692 struct ref_entry *entry = dir->entries[i];
693 if (entry->flag & REF_DIR)
694 prime_ref_dir(get_ref_dir(entry));
695 }
696}
697
698struct nonmatching_ref_data {
699 const struct string_list *skip;
700 const char *conflicting_refname;
701};
702
703static int nonmatching_ref_fn(struct ref_entry *entry, void *vdata)
704{
705 struct nonmatching_ref_data *data = vdata;
706
707 if (data->skip && string_list_has_string(data->skip, entry->name))
708 return 0;
709
710 data->conflicting_refname = entry->name;
711 return 1;
712}
713
714/*
715 * Return 0 if a reference named refname could be created without
716 * conflicting with the name of an existing reference in dir.
717 * See verify_refname_available for more information.
718 */
719static int verify_refname_available_dir(const char *refname,
720 const struct string_list *extras,
721 const struct string_list *skip,
722 struct ref_dir *dir,
723 struct strbuf *err)
724{
725 const char *slash;
0845122c 726 const char *extra_refname;
7bd9bcf3
MH
727 int pos;
728 struct strbuf dirname = STRBUF_INIT;
729 int ret = -1;
730
731 /*
732 * For the sake of comments in this function, suppose that
733 * refname is "refs/foo/bar".
734 */
735
736 assert(err);
737
738 strbuf_grow(&dirname, strlen(refname) + 1);
739 for (slash = strchr(refname, '/'); slash; slash = strchr(slash + 1, '/')) {
740 /* Expand dirname to the new prefix, not including the trailing slash: */
741 strbuf_add(&dirname, refname + dirname.len, slash - refname - dirname.len);
742
743 /*
744 * We are still at a leading dir of the refname (e.g.,
745 * "refs/foo"; if there is a reference with that name,
746 * it is a conflict, *unless* it is in skip.
747 */
748 if (dir) {
749 pos = search_ref_dir(dir, dirname.buf, dirname.len);
750 if (pos >= 0 &&
751 (!skip || !string_list_has_string(skip, dirname.buf))) {
752 /*
753 * We found a reference whose name is
754 * a proper prefix of refname; e.g.,
755 * "refs/foo", and is not in skip.
756 */
757 strbuf_addf(err, "'%s' exists; cannot create '%s'",
758 dirname.buf, refname);
759 goto cleanup;
760 }
761 }
762
763 if (extras && string_list_has_string(extras, dirname.buf) &&
764 (!skip || !string_list_has_string(skip, dirname.buf))) {
765 strbuf_addf(err, "cannot process '%s' and '%s' at the same time",
766 refname, dirname.buf);
767 goto cleanup;
768 }
769
770 /*
771 * Otherwise, we can try to continue our search with
772 * the next component. So try to look up the
773 * directory, e.g., "refs/foo/". If we come up empty,
774 * we know there is nothing under this whole prefix,
775 * but even in that case we still have to continue the
776 * search for conflicts with extras.
777 */
778 strbuf_addch(&dirname, '/');
779 if (dir) {
780 pos = search_ref_dir(dir, dirname.buf, dirname.len);
781 if (pos < 0) {
782 /*
783 * There was no directory "refs/foo/",
784 * so there is nothing under this
785 * whole prefix. So there is no need
786 * to continue looking for conflicting
787 * references. But we need to continue
788 * looking for conflicting extras.
789 */
790 dir = NULL;
791 } else {
792 dir = get_ref_dir(dir->entries[pos]);
793 }
794 }
795 }
796
797 /*
798 * We are at the leaf of our refname (e.g., "refs/foo/bar").
799 * There is no point in searching for a reference with that
800 * name, because a refname isn't considered to conflict with
801 * itself. But we still need to check for references whose
802 * names are in the "refs/foo/bar/" namespace, because they
803 * *do* conflict.
804 */
805 strbuf_addstr(&dirname, refname + dirname.len);
806 strbuf_addch(&dirname, '/');
807
808 if (dir) {
809 pos = search_ref_dir(dir, dirname.buf, dirname.len);
810
811 if (pos >= 0) {
812 /*
813 * We found a directory named "$refname/"
814 * (e.g., "refs/foo/bar/"). It is a problem
815 * iff it contains any ref that is not in
816 * "skip".
817 */
818 struct nonmatching_ref_data data;
819
820 data.skip = skip;
821 data.conflicting_refname = NULL;
822 dir = get_ref_dir(dir->entries[pos]);
823 sort_ref_dir(dir);
824 if (do_for_each_entry_in_dir(dir, 0, nonmatching_ref_fn, &data)) {
825 strbuf_addf(err, "'%s' exists; cannot create '%s'",
826 data.conflicting_refname, refname);
827 goto cleanup;
828 }
829 }
830 }
831
0845122c
DT
832 extra_refname = find_descendant_ref(dirname.buf, extras, skip);
833 if (extra_refname)
834 strbuf_addf(err, "cannot process '%s' and '%s' at the same time",
835 refname, extra_refname);
836 else
837 ret = 0;
7bd9bcf3
MH
838
839cleanup:
840 strbuf_release(&dirname);
841 return ret;
842}
843
844struct packed_ref_cache {
845 struct ref_entry *root;
846
847 /*
848 * Count of references to the data structure in this instance,
849 * including the pointer from ref_cache::packed if any. The
850 * data will not be freed as long as the reference count is
851 * nonzero.
852 */
853 unsigned int referrers;
854
855 /*
856 * Iff the packed-refs file associated with this instance is
857 * currently locked for writing, this points at the associated
858 * lock (which is owned by somebody else). The referrer count
859 * is also incremented when the file is locked and decremented
860 * when it is unlocked.
861 */
862 struct lock_file *lock;
863
864 /* The metadata from when this packed-refs cache was read */
865 struct stat_validity validity;
866};
867
868/*
869 * Future: need to be in "struct repository"
870 * when doing a full libification.
871 */
872static struct ref_cache {
873 struct ref_cache *next;
874 struct ref_entry *loose;
875 struct packed_ref_cache *packed;
876 /*
877 * The submodule name, or "" for the main repo. We allocate
878 * length 1 rather than FLEX_ARRAY so that the main ref_cache
879 * is initialized correctly.
880 */
881 char name[1];
882} ref_cache, *submodule_ref_caches;
883
884/* Lock used for the main packed-refs file: */
885static struct lock_file packlock;
886
887/*
888 * Increment the reference count of *packed_refs.
889 */
890static void acquire_packed_ref_cache(struct packed_ref_cache *packed_refs)
891{
892 packed_refs->referrers++;
893}
894
895/*
896 * Decrease the reference count of *packed_refs. If it goes to zero,
897 * free *packed_refs and return true; otherwise return false.
898 */
899static int release_packed_ref_cache(struct packed_ref_cache *packed_refs)
900{
901 if (!--packed_refs->referrers) {
902 free_ref_entry(packed_refs->root);
903 stat_validity_clear(&packed_refs->validity);
904 free(packed_refs);
905 return 1;
906 } else {
907 return 0;
908 }
909}
910
911static void clear_packed_ref_cache(struct ref_cache *refs)
912{
913 if (refs->packed) {
914 struct packed_ref_cache *packed_refs = refs->packed;
915
916 if (packed_refs->lock)
917 die("internal error: packed-ref cache cleared while locked");
918 refs->packed = NULL;
919 release_packed_ref_cache(packed_refs);
920 }
921}
922
923static void clear_loose_ref_cache(struct ref_cache *refs)
924{
925 if (refs->loose) {
926 free_ref_entry(refs->loose);
927 refs->loose = NULL;
928 }
929}
930
a2d5156c
JK
931/*
932 * Create a new submodule ref cache and add it to the internal
933 * set of caches.
934 */
7bd9bcf3
MH
935static struct ref_cache *create_ref_cache(const char *submodule)
936{
7bd9bcf3
MH
937 struct ref_cache *refs;
938 if (!submodule)
939 submodule = "";
96ffc06f 940 FLEX_ALLOC_STR(refs, name, submodule);
a2d5156c
JK
941 refs->next = submodule_ref_caches;
942 submodule_ref_caches = refs;
7bd9bcf3
MH
943 return refs;
944}
945
a2d5156c 946static struct ref_cache *lookup_ref_cache(const char *submodule)
7bd9bcf3
MH
947{
948 struct ref_cache *refs;
949
950 if (!submodule || !*submodule)
951 return &ref_cache;
952
953 for (refs = submodule_ref_caches; refs; refs = refs->next)
954 if (!strcmp(submodule, refs->name))
955 return refs;
a2d5156c
JK
956 return NULL;
957}
7bd9bcf3 958
a2d5156c
JK
959/*
960 * Return a pointer to a ref_cache for the specified submodule. For
961 * the main repository, use submodule==NULL. The returned structure
962 * will be allocated and initialized but not necessarily populated; it
963 * should not be freed.
964 */
965static struct ref_cache *get_ref_cache(const char *submodule)
966{
967 struct ref_cache *refs = lookup_ref_cache(submodule);
968 if (!refs)
969 refs = create_ref_cache(submodule);
7bd9bcf3
MH
970 return refs;
971}
972
973/* The length of a peeled reference line in packed-refs, including EOL: */
974#define PEELED_LINE_LENGTH 42
975
976/*
977 * The packed-refs header line that we write out. Perhaps other
978 * traits will be added later. The trailing space is required.
979 */
980static const char PACKED_REFS_HEADER[] =
981 "# pack-refs with: peeled fully-peeled \n";
982
983/*
984 * Parse one line from a packed-refs file. Write the SHA1 to sha1.
985 * Return a pointer to the refname within the line (null-terminated),
986 * or NULL if there was a problem.
987 */
988static const char *parse_ref_line(struct strbuf *line, unsigned char *sha1)
989{
990 const char *ref;
991
992 /*
993 * 42: the answer to everything.
994 *
995 * In this case, it happens to be the answer to
996 * 40 (length of sha1 hex representation)
997 * +1 (space in between hex and name)
998 * +1 (newline at the end of the line)
999 */
1000 if (line->len <= 42)
1001 return NULL;
1002
1003 if (get_sha1_hex(line->buf, sha1) < 0)
1004 return NULL;
1005 if (!isspace(line->buf[40]))
1006 return NULL;
1007
1008 ref = line->buf + 41;
1009 if (isspace(*ref))
1010 return NULL;
1011
1012 if (line->buf[line->len - 1] != '\n')
1013 return NULL;
1014 line->buf[--line->len] = 0;
1015
1016 return ref;
1017}
1018
1019/*
1020 * Read f, which is a packed-refs file, into dir.
1021 *
1022 * A comment line of the form "# pack-refs with: " may contain zero or
1023 * more traits. We interpret the traits as follows:
1024 *
1025 * No traits:
1026 *
1027 * Probably no references are peeled. But if the file contains a
1028 * peeled value for a reference, we will use it.
1029 *
1030 * peeled:
1031 *
1032 * References under "refs/tags/", if they *can* be peeled, *are*
1033 * peeled in this file. References outside of "refs/tags/" are
1034 * probably not peeled even if they could have been, but if we find
1035 * a peeled value for such a reference we will use it.
1036 *
1037 * fully-peeled:
1038 *
1039 * All references in the file that can be peeled are peeled.
1040 * Inversely (and this is more important), any references in the
1041 * file for which no peeled value is recorded is not peelable. This
1042 * trait should typically be written alongside "peeled" for
1043 * compatibility with older clients, but we do not require it
1044 * (i.e., "peeled" is a no-op if "fully-peeled" is set).
1045 */
1046static void read_packed_refs(FILE *f, struct ref_dir *dir)
1047{
1048 struct ref_entry *last = NULL;
1049 struct strbuf line = STRBUF_INIT;
1050 enum { PEELED_NONE, PEELED_TAGS, PEELED_FULLY } peeled = PEELED_NONE;
1051
1052 while (strbuf_getwholeline(&line, f, '\n') != EOF) {
1053 unsigned char sha1[20];
1054 const char *refname;
1055 const char *traits;
1056
1057 if (skip_prefix(line.buf, "# pack-refs with:", &traits)) {
1058 if (strstr(traits, " fully-peeled "))
1059 peeled = PEELED_FULLY;
1060 else if (strstr(traits, " peeled "))
1061 peeled = PEELED_TAGS;
1062 /* perhaps other traits later as well */
1063 continue;
1064 }
1065
1066 refname = parse_ref_line(&line, sha1);
1067 if (refname) {
1068 int flag = REF_ISPACKED;
1069
1070 if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
1071 if (!refname_is_safe(refname))
1072 die("packed refname is dangerous: %s", refname);
1073 hashclr(sha1);
1074 flag |= REF_BAD_NAME | REF_ISBROKEN;
1075 }
1076 last = create_ref_entry(refname, sha1, flag, 0);
1077 if (peeled == PEELED_FULLY ||
1078 (peeled == PEELED_TAGS && starts_with(refname, "refs/tags/")))
1079 last->flag |= REF_KNOWS_PEELED;
1080 add_ref(dir, last);
1081 continue;
1082 }
1083 if (last &&
1084 line.buf[0] == '^' &&
1085 line.len == PEELED_LINE_LENGTH &&
1086 line.buf[PEELED_LINE_LENGTH - 1] == '\n' &&
1087 !get_sha1_hex(line.buf + 1, sha1)) {
1088 hashcpy(last->u.value.peeled.hash, sha1);
1089 /*
1090 * Regardless of what the file header said,
1091 * we definitely know the value of *this*
1092 * reference:
1093 */
1094 last->flag |= REF_KNOWS_PEELED;
1095 }
1096 }
1097
1098 strbuf_release(&line);
1099}
1100
1101/*
1102 * Get the packed_ref_cache for the specified ref_cache, creating it
1103 * if necessary.
1104 */
1105static struct packed_ref_cache *get_packed_ref_cache(struct ref_cache *refs)
1106{
1107 char *packed_refs_file;
1108
1109 if (*refs->name)
1110 packed_refs_file = git_pathdup_submodule(refs->name, "packed-refs");
1111 else
1112 packed_refs_file = git_pathdup("packed-refs");
1113
1114 if (refs->packed &&
1115 !stat_validity_check(&refs->packed->validity, packed_refs_file))
1116 clear_packed_ref_cache(refs);
1117
1118 if (!refs->packed) {
1119 FILE *f;
1120
1121 refs->packed = xcalloc(1, sizeof(*refs->packed));
1122 acquire_packed_ref_cache(refs->packed);
1123 refs->packed->root = create_dir_entry(refs, "", 0, 0);
1124 f = fopen(packed_refs_file, "r");
1125 if (f) {
1126 stat_validity_update(&refs->packed->validity, fileno(f));
1127 read_packed_refs(f, get_ref_dir(refs->packed->root));
1128 fclose(f);
1129 }
1130 }
1131 free(packed_refs_file);
1132 return refs->packed;
1133}
1134
1135static struct ref_dir *get_packed_ref_dir(struct packed_ref_cache *packed_ref_cache)
1136{
1137 return get_ref_dir(packed_ref_cache->root);
1138}
1139
1140static struct ref_dir *get_packed_refs(struct ref_cache *refs)
1141{
1142 return get_packed_ref_dir(get_packed_ref_cache(refs));
1143}
1144
1145/*
1146 * Add a reference to the in-memory packed reference cache. This may
1147 * only be called while the packed-refs file is locked (see
1148 * lock_packed_refs()). To actually write the packed-refs file, call
1149 * commit_packed_refs().
1150 */
1151static void add_packed_ref(const char *refname, const unsigned char *sha1)
1152{
1153 struct packed_ref_cache *packed_ref_cache =
1154 get_packed_ref_cache(&ref_cache);
1155
1156 if (!packed_ref_cache->lock)
1157 die("internal error: packed refs not locked");
1158 add_ref(get_packed_ref_dir(packed_ref_cache),
1159 create_ref_entry(refname, sha1, REF_ISPACKED, 1));
1160}
1161
1162/*
1163 * Read the loose references from the namespace dirname into dir
1164 * (without recursing). dirname must end with '/'. dir must be the
1165 * directory entry corresponding to dirname.
1166 */
1167static void read_loose_refs(const char *dirname, struct ref_dir *dir)
1168{
1169 struct ref_cache *refs = dir->ref_cache;
1170 DIR *d;
1171 struct dirent *de;
1172 int dirnamelen = strlen(dirname);
1173 struct strbuf refname;
1174 struct strbuf path = STRBUF_INIT;
1175 size_t path_baselen;
1176
1177 if (*refs->name)
1178 strbuf_git_path_submodule(&path, refs->name, "%s", dirname);
1179 else
1180 strbuf_git_path(&path, "%s", dirname);
1181 path_baselen = path.len;
1182
1183 d = opendir(path.buf);
1184 if (!d) {
1185 strbuf_release(&path);
1186 return;
1187 }
1188
1189 strbuf_init(&refname, dirnamelen + 257);
1190 strbuf_add(&refname, dirname, dirnamelen);
1191
1192 while ((de = readdir(d)) != NULL) {
1193 unsigned char sha1[20];
1194 struct stat st;
1195 int flag;
1196
1197 if (de->d_name[0] == '.')
1198 continue;
1199 if (ends_with(de->d_name, ".lock"))
1200 continue;
1201 strbuf_addstr(&refname, de->d_name);
1202 strbuf_addstr(&path, de->d_name);
1203 if (stat(path.buf, &st) < 0) {
1204 ; /* silently ignore */
1205 } else if (S_ISDIR(st.st_mode)) {
1206 strbuf_addch(&refname, '/');
1207 add_entry_to_dir(dir,
1208 create_dir_entry(refs, refname.buf,
1209 refname.len, 1));
1210 } else {
1211 int read_ok;
1212
1213 if (*refs->name) {
1214 hashclr(sha1);
1215 flag = 0;
1216 read_ok = !resolve_gitlink_ref(refs->name,
1217 refname.buf, sha1);
1218 } else {
1219 read_ok = !read_ref_full(refname.buf,
1220 RESOLVE_REF_READING,
1221 sha1, &flag);
1222 }
1223
1224 if (!read_ok) {
1225 hashclr(sha1);
1226 flag |= REF_ISBROKEN;
1227 } else if (is_null_sha1(sha1)) {
1228 /*
1229 * It is so astronomically unlikely
1230 * that NULL_SHA1 is the SHA-1 of an
1231 * actual object that we consider its
1232 * appearance in a loose reference
1233 * file to be repo corruption
1234 * (probably due to a software bug).
1235 */
1236 flag |= REF_ISBROKEN;
1237 }
1238
1239 if (check_refname_format(refname.buf,
1240 REFNAME_ALLOW_ONELEVEL)) {
1241 if (!refname_is_safe(refname.buf))
1242 die("loose refname is dangerous: %s", refname.buf);
1243 hashclr(sha1);
1244 flag |= REF_BAD_NAME | REF_ISBROKEN;
1245 }
1246 add_entry_to_dir(dir,
1247 create_ref_entry(refname.buf, sha1, flag, 0));
1248 }
1249 strbuf_setlen(&refname, dirnamelen);
1250 strbuf_setlen(&path, path_baselen);
1251 }
1252 strbuf_release(&refname);
1253 strbuf_release(&path);
1254 closedir(d);
1255}
1256
1257static struct ref_dir *get_loose_refs(struct ref_cache *refs)
1258{
1259 if (!refs->loose) {
1260 /*
1261 * Mark the top-level directory complete because we
1262 * are about to read the only subdirectory that can
1263 * hold references:
1264 */
1265 refs->loose = create_dir_entry(refs, "", 0, 0);
1266 /*
1267 * Create an incomplete entry for "refs/":
1268 */
1269 add_entry_to_dir(get_ref_dir(refs->loose),
1270 create_dir_entry(refs, "refs/", 5, 1));
1271 }
1272 return get_ref_dir(refs->loose);
1273}
1274
1275/* We allow "recursive" symbolic refs. Only within reason, though */
1276#define MAXDEPTH 5
1277#define MAXREFLEN (1024)
1278
1279/*
1280 * Called by resolve_gitlink_ref_recursive() after it failed to read
1281 * from the loose refs in ref_cache refs. Find <refname> in the
1282 * packed-refs file for the submodule.
1283 */
1284static int resolve_gitlink_packed_ref(struct ref_cache *refs,
1285 const char *refname, unsigned char *sha1)
1286{
1287 struct ref_entry *ref;
1288 struct ref_dir *dir = get_packed_refs(refs);
1289
1290 ref = find_ref(dir, refname);
1291 if (ref == NULL)
1292 return -1;
1293
1294 hashcpy(sha1, ref->u.value.oid.hash);
1295 return 0;
1296}
1297
1298static int resolve_gitlink_ref_recursive(struct ref_cache *refs,
1299 const char *refname, unsigned char *sha1,
1300 int recursion)
1301{
1302 int fd, len;
1303 char buffer[128], *p;
1304 char *path;
1305
1306 if (recursion > MAXDEPTH || strlen(refname) > MAXREFLEN)
1307 return -1;
1308 path = *refs->name
1309 ? git_pathdup_submodule(refs->name, "%s", refname)
1310 : git_pathdup("%s", refname);
1311 fd = open(path, O_RDONLY);
1312 free(path);
1313 if (fd < 0)
1314 return resolve_gitlink_packed_ref(refs, refname, sha1);
1315
1316 len = read(fd, buffer, sizeof(buffer)-1);
1317 close(fd);
1318 if (len < 0)
1319 return -1;
1320 while (len && isspace(buffer[len-1]))
1321 len--;
1322 buffer[len] = 0;
1323
1324 /* Was it a detached head or an old-fashioned symlink? */
1325 if (!get_sha1_hex(buffer, sha1))
1326 return 0;
1327
1328 /* Symref? */
1329 if (strncmp(buffer, "ref:", 4))
1330 return -1;
1331 p = buffer + 4;
1332 while (isspace(*p))
1333 p++;
1334
1335 return resolve_gitlink_ref_recursive(refs, p, sha1, recursion+1);
1336}
1337
1338int resolve_gitlink_ref(const char *path, const char *refname, unsigned char *sha1)
1339{
1340 int len = strlen(path), retval;
a2d5156c 1341 struct strbuf submodule = STRBUF_INIT;
7bd9bcf3
MH
1342 struct ref_cache *refs;
1343
1344 while (len && path[len-1] == '/')
1345 len--;
1346 if (!len)
1347 return -1;
a2d5156c
JK
1348
1349 strbuf_add(&submodule, path, len);
1350 refs = lookup_ref_cache(submodule.buf);
1351 if (!refs) {
1352 if (!is_nonbare_repository_dir(&submodule)) {
1353 strbuf_release(&submodule);
1354 return -1;
1355 }
1356 refs = create_ref_cache(submodule.buf);
1357 }
1358 strbuf_release(&submodule);
7bd9bcf3
MH
1359
1360 retval = resolve_gitlink_ref_recursive(refs, refname, sha1, 0);
1361 return retval;
1362}
1363
1364/*
1365 * Return the ref_entry for the given refname from the packed
1366 * references. If it does not exist, return NULL.
1367 */
1368static struct ref_entry *get_packed_ref(const char *refname)
1369{
1370 return find_ref(get_packed_refs(&ref_cache), refname);
1371}
1372
1373/*
1374 * A loose ref file doesn't exist; check for a packed ref. The
1375 * options are forwarded from resolve_safe_unsafe().
1376 */
1377static int resolve_missing_loose_ref(const char *refname,
1378 int resolve_flags,
1379 unsigned char *sha1,
1380 int *flags)
1381{
1382 struct ref_entry *entry;
1383
1384 /*
1385 * The loose reference file does not exist; check for a packed
1386 * reference.
1387 */
1388 entry = get_packed_ref(refname);
1389 if (entry) {
1390 hashcpy(sha1, entry->u.value.oid.hash);
1391 if (flags)
1392 *flags |= REF_ISPACKED;
1393 return 0;
1394 }
1395 /* The reference is not a packed reference, either. */
1396 if (resolve_flags & RESOLVE_REF_READING) {
1397 errno = ENOENT;
1398 return -1;
1399 } else {
1400 hashclr(sha1);
1401 return 0;
1402 }
1403}
1404
1405/* This function needs to return a meaningful errno on failure */
1406static const char *resolve_ref_1(const char *refname,
1407 int resolve_flags,
1408 unsigned char *sha1,
1409 int *flags,
1410 struct strbuf *sb_refname,
1411 struct strbuf *sb_path,
1412 struct strbuf *sb_contents)
1413{
1414 int depth = MAXDEPTH;
1415 int bad_name = 0;
1416
1417 if (flags)
1418 *flags = 0;
1419
1420 if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
1421 if (flags)
1422 *flags |= REF_BAD_NAME;
1423
1424 if (!(resolve_flags & RESOLVE_REF_ALLOW_BAD_NAME) ||
1425 !refname_is_safe(refname)) {
1426 errno = EINVAL;
1427 return NULL;
1428 }
1429 /*
1430 * dwim_ref() uses REF_ISBROKEN to distinguish between
1431 * missing refs and refs that were present but invalid,
1432 * to complain about the latter to stderr.
1433 *
1434 * We don't know whether the ref exists, so don't set
1435 * REF_ISBROKEN yet.
1436 */
1437 bad_name = 1;
1438 }
1439 for (;;) {
1440 const char *path;
1441 struct stat st;
1442 char *buf;
1443 int fd;
1444
1445 if (--depth < 0) {
1446 errno = ELOOP;
1447 return NULL;
1448 }
1449
1450 strbuf_reset(sb_path);
1451 strbuf_git_path(sb_path, "%s", refname);
1452 path = sb_path->buf;
1453
1454 /*
1455 * We might have to loop back here to avoid a race
1456 * condition: first we lstat() the file, then we try
1457 * to read it as a link or as a file. But if somebody
1458 * changes the type of the file (file <-> directory
1459 * <-> symlink) between the lstat() and reading, then
1460 * we don't want to report that as an error but rather
1461 * try again starting with the lstat().
1462 */
1463 stat_ref:
1464 if (lstat(path, &st) < 0) {
1465 if (errno != ENOENT)
1466 return NULL;
1467 if (resolve_missing_loose_ref(refname, resolve_flags,
1468 sha1, flags))
1469 return NULL;
1470 if (bad_name) {
1471 hashclr(sha1);
1472 if (flags)
1473 *flags |= REF_ISBROKEN;
1474 }
1475 return refname;
1476 }
1477
1478 /* Follow "normalized" - ie "refs/.." symlinks by hand */
1479 if (S_ISLNK(st.st_mode)) {
1480 strbuf_reset(sb_contents);
1481 if (strbuf_readlink(sb_contents, path, 0) < 0) {
1482 if (errno == ENOENT || errno == EINVAL)
1483 /* inconsistent with lstat; retry */
1484 goto stat_ref;
1485 else
1486 return NULL;
1487 }
1488 if (starts_with(sb_contents->buf, "refs/") &&
1489 !check_refname_format(sb_contents->buf, 0)) {
1490 strbuf_swap(sb_refname, sb_contents);
1491 refname = sb_refname->buf;
1492 if (flags)
1493 *flags |= REF_ISSYMREF;
1494 if (resolve_flags & RESOLVE_REF_NO_RECURSE) {
1495 hashclr(sha1);
1496 return refname;
1497 }
1498 continue;
1499 }
1500 }
1501
1502 /* Is it a directory? */
1503 if (S_ISDIR(st.st_mode)) {
1504 errno = EISDIR;
1505 return NULL;
1506 }
1507
1508 /*
1509 * Anything else, just open it and try to use it as
1510 * a ref
1511 */
1512 fd = open(path, O_RDONLY);
1513 if (fd < 0) {
1514 if (errno == ENOENT)
1515 /* inconsistent with lstat; retry */
1516 goto stat_ref;
1517 else
1518 return NULL;
1519 }
1520 strbuf_reset(sb_contents);
1521 if (strbuf_read(sb_contents, fd, 256) < 0) {
1522 int save_errno = errno;
1523 close(fd);
1524 errno = save_errno;
1525 return NULL;
1526 }
1527 close(fd);
1528 strbuf_rtrim(sb_contents);
1529
1530 /*
1531 * Is it a symbolic ref?
1532 */
1533 if (!starts_with(sb_contents->buf, "ref:")) {
1534 /*
1535 * Please note that FETCH_HEAD has a second
1536 * line containing other data.
1537 */
1538 if (get_sha1_hex(sb_contents->buf, sha1) ||
1539 (sb_contents->buf[40] != '\0' && !isspace(sb_contents->buf[40]))) {
1540 if (flags)
1541 *flags |= REF_ISBROKEN;
1542 errno = EINVAL;
1543 return NULL;
1544 }
1545 if (bad_name) {
1546 hashclr(sha1);
1547 if (flags)
1548 *flags |= REF_ISBROKEN;
1549 }
1550 return refname;
1551 }
1552 if (flags)
1553 *flags |= REF_ISSYMREF;
1554 buf = sb_contents->buf + 4;
1555 while (isspace(*buf))
1556 buf++;
1557 strbuf_reset(sb_refname);
1558 strbuf_addstr(sb_refname, buf);
1559 refname = sb_refname->buf;
1560 if (resolve_flags & RESOLVE_REF_NO_RECURSE) {
1561 hashclr(sha1);
1562 return refname;
1563 }
1564 if (check_refname_format(buf, REFNAME_ALLOW_ONELEVEL)) {
1565 if (flags)
1566 *flags |= REF_ISBROKEN;
1567
1568 if (!(resolve_flags & RESOLVE_REF_ALLOW_BAD_NAME) ||
1569 !refname_is_safe(buf)) {
1570 errno = EINVAL;
1571 return NULL;
1572 }
1573 bad_name = 1;
1574 }
1575 }
1576}
1577
1578const char *resolve_ref_unsafe(const char *refname, int resolve_flags,
1579 unsigned char *sha1, int *flags)
1580{
1581 static struct strbuf sb_refname = STRBUF_INIT;
1582 struct strbuf sb_contents = STRBUF_INIT;
1583 struct strbuf sb_path = STRBUF_INIT;
1584 const char *ret;
1585
1586 ret = resolve_ref_1(refname, resolve_flags, sha1, flags,
1587 &sb_refname, &sb_path, &sb_contents);
1588 strbuf_release(&sb_path);
1589 strbuf_release(&sb_contents);
1590 return ret;
1591}
1592
1593/*
1594 * Peel the entry (if possible) and return its new peel_status. If
1595 * repeel is true, re-peel the entry even if there is an old peeled
1596 * value that is already stored in it.
1597 *
1598 * It is OK to call this function with a packed reference entry that
1599 * might be stale and might even refer to an object that has since
1600 * been garbage-collected. In such a case, if the entry has
1601 * REF_KNOWS_PEELED then leave the status unchanged and return
1602 * PEEL_PEELED or PEEL_NON_TAG; otherwise, return PEEL_INVALID.
1603 */
1604static enum peel_status peel_entry(struct ref_entry *entry, int repeel)
1605{
1606 enum peel_status status;
1607
1608 if (entry->flag & REF_KNOWS_PEELED) {
1609 if (repeel) {
1610 entry->flag &= ~REF_KNOWS_PEELED;
1611 oidclr(&entry->u.value.peeled);
1612 } else {
1613 return is_null_oid(&entry->u.value.peeled) ?
1614 PEEL_NON_TAG : PEEL_PEELED;
1615 }
1616 }
1617 if (entry->flag & REF_ISBROKEN)
1618 return PEEL_BROKEN;
1619 if (entry->flag & REF_ISSYMREF)
1620 return PEEL_IS_SYMREF;
1621
1622 status = peel_object(entry->u.value.oid.hash, entry->u.value.peeled.hash);
1623 if (status == PEEL_PEELED || status == PEEL_NON_TAG)
1624 entry->flag |= REF_KNOWS_PEELED;
1625 return status;
1626}
1627
1628int peel_ref(const char *refname, unsigned char *sha1)
1629{
1630 int flag;
1631 unsigned char base[20];
1632
1633 if (current_ref && (current_ref->name == refname
1634 || !strcmp(current_ref->name, refname))) {
1635 if (peel_entry(current_ref, 0))
1636 return -1;
1637 hashcpy(sha1, current_ref->u.value.peeled.hash);
1638 return 0;
1639 }
1640
1641 if (read_ref_full(refname, RESOLVE_REF_READING, base, &flag))
1642 return -1;
1643
1644 /*
1645 * If the reference is packed, read its ref_entry from the
1646 * cache in the hope that we already know its peeled value.
1647 * We only try this optimization on packed references because
1648 * (a) forcing the filling of the loose reference cache could
1649 * be expensive and (b) loose references anyway usually do not
1650 * have REF_KNOWS_PEELED.
1651 */
1652 if (flag & REF_ISPACKED) {
1653 struct ref_entry *r = get_packed_ref(refname);
1654 if (r) {
1655 if (peel_entry(r, 0))
1656 return -1;
1657 hashcpy(sha1, r->u.value.peeled.hash);
1658 return 0;
1659 }
1660 }
1661
1662 return peel_object(base, sha1);
1663}
1664
1665/*
1666 * Call fn for each reference in the specified ref_cache, omitting
1667 * references not in the containing_dir of base. fn is called for all
1668 * references, including broken ones. If fn ever returns a non-zero
1669 * value, stop the iteration and return that value; otherwise, return
1670 * 0.
1671 */
1672static int do_for_each_entry(struct ref_cache *refs, const char *base,
1673 each_ref_entry_fn fn, void *cb_data)
1674{
1675 struct packed_ref_cache *packed_ref_cache;
1676 struct ref_dir *loose_dir;
1677 struct ref_dir *packed_dir;
1678 int retval = 0;
1679
1680 /*
1681 * We must make sure that all loose refs are read before accessing the
1682 * packed-refs file; this avoids a race condition in which loose refs
1683 * are migrated to the packed-refs file by a simultaneous process, but
1684 * our in-memory view is from before the migration. get_packed_ref_cache()
1685 * takes care of making sure our view is up to date with what is on
1686 * disk.
1687 */
1688 loose_dir = get_loose_refs(refs);
1689 if (base && *base) {
1690 loose_dir = find_containing_dir(loose_dir, base, 0);
1691 }
1692 if (loose_dir)
1693 prime_ref_dir(loose_dir);
1694
1695 packed_ref_cache = get_packed_ref_cache(refs);
1696 acquire_packed_ref_cache(packed_ref_cache);
1697 packed_dir = get_packed_ref_dir(packed_ref_cache);
1698 if (base && *base) {
1699 packed_dir = find_containing_dir(packed_dir, base, 0);
1700 }
1701
1702 if (packed_dir && loose_dir) {
1703 sort_ref_dir(packed_dir);
1704 sort_ref_dir(loose_dir);
1705 retval = do_for_each_entry_in_dirs(
1706 packed_dir, loose_dir, fn, cb_data);
1707 } else if (packed_dir) {
1708 sort_ref_dir(packed_dir);
1709 retval = do_for_each_entry_in_dir(
1710 packed_dir, 0, fn, cb_data);
1711 } else if (loose_dir) {
1712 sort_ref_dir(loose_dir);
1713 retval = do_for_each_entry_in_dir(
1714 loose_dir, 0, fn, cb_data);
1715 }
1716
1717 release_packed_ref_cache(packed_ref_cache);
1718 return retval;
1719}
1720
1721/*
1722 * Call fn for each reference in the specified ref_cache for which the
1723 * refname begins with base. If trim is non-zero, then trim that many
1724 * characters off the beginning of each refname before passing the
1725 * refname to fn. flags can be DO_FOR_EACH_INCLUDE_BROKEN to include
1726 * broken references in the iteration. If fn ever returns a non-zero
1727 * value, stop the iteration and return that value; otherwise, return
1728 * 0.
1729 */
1730static int do_for_each_ref(struct ref_cache *refs, const char *base,
1731 each_ref_fn fn, int trim, int flags, void *cb_data)
1732{
1733 struct ref_entry_cb data;
1734 data.base = base;
1735 data.trim = trim;
1736 data.flags = flags;
1737 data.fn = fn;
1738 data.cb_data = cb_data;
1739
1740 if (ref_paranoia < 0)
1741 ref_paranoia = git_env_bool("GIT_REF_PARANOIA", 0);
1742 if (ref_paranoia)
1743 data.flags |= DO_FOR_EACH_INCLUDE_BROKEN;
1744
1745 return do_for_each_entry(refs, base, do_one_ref, &data);
1746}
1747
1748static int do_head_ref(const char *submodule, each_ref_fn fn, void *cb_data)
1749{
1750 struct object_id oid;
1751 int flag;
1752
1753 if (submodule) {
1754 if (resolve_gitlink_ref(submodule, "HEAD", oid.hash) == 0)
1755 return fn("HEAD", &oid, 0, cb_data);
1756
1757 return 0;
1758 }
1759
1760 if (!read_ref_full("HEAD", RESOLVE_REF_READING, oid.hash, &flag))
1761 return fn("HEAD", &oid, flag, cb_data);
1762
1763 return 0;
1764}
1765
1766int head_ref(each_ref_fn fn, void *cb_data)
1767{
1768 return do_head_ref(NULL, fn, cb_data);
1769}
1770
1771int head_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
1772{
1773 return do_head_ref(submodule, fn, cb_data);
1774}
1775
1776int for_each_ref(each_ref_fn fn, void *cb_data)
1777{
1778 return do_for_each_ref(&ref_cache, "", fn, 0, 0, cb_data);
1779}
1780
1781int for_each_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
1782{
1783 return do_for_each_ref(get_ref_cache(submodule), "", fn, 0, 0, cb_data);
1784}
1785
1786int for_each_ref_in(const char *prefix, each_ref_fn fn, void *cb_data)
1787{
1788 return do_for_each_ref(&ref_cache, prefix, fn, strlen(prefix), 0, cb_data);
1789}
1790
1791int for_each_fullref_in(const char *prefix, each_ref_fn fn, void *cb_data, unsigned int broken)
1792{
1793 unsigned int flag = 0;
1794
1795 if (broken)
1796 flag = DO_FOR_EACH_INCLUDE_BROKEN;
1797 return do_for_each_ref(&ref_cache, prefix, fn, 0, flag, cb_data);
1798}
1799
1800int for_each_ref_in_submodule(const char *submodule, const char *prefix,
1801 each_ref_fn fn, void *cb_data)
1802{
1803 return do_for_each_ref(get_ref_cache(submodule), prefix, fn, strlen(prefix), 0, cb_data);
1804}
1805
1806int for_each_replace_ref(each_ref_fn fn, void *cb_data)
1807{
1808 return do_for_each_ref(&ref_cache, git_replace_ref_base, fn,
1809 strlen(git_replace_ref_base), 0, cb_data);
1810}
1811
1812int for_each_namespaced_ref(each_ref_fn fn, void *cb_data)
1813{
1814 struct strbuf buf = STRBUF_INIT;
1815 int ret;
1816 strbuf_addf(&buf, "%srefs/", get_git_namespace());
1817 ret = do_for_each_ref(&ref_cache, buf.buf, fn, 0, 0, cb_data);
1818 strbuf_release(&buf);
1819 return ret;
1820}
1821
1822int for_each_rawref(each_ref_fn fn, void *cb_data)
1823{
1824 return do_for_each_ref(&ref_cache, "", fn, 0,
1825 DO_FOR_EACH_INCLUDE_BROKEN, cb_data);
1826}
1827
1828static void unlock_ref(struct ref_lock *lock)
1829{
1830 /* Do not free lock->lk -- atexit() still looks at them */
1831 if (lock->lk)
1832 rollback_lock_file(lock->lk);
1833 free(lock->ref_name);
1834 free(lock->orig_ref_name);
1835 free(lock);
1836}
1837
1838/*
1839 * Verify that the reference locked by lock has the value old_sha1.
1840 * Fail if the reference doesn't exist and mustexist is set. Return 0
1841 * on success. On error, write an error message to err, set errno, and
1842 * return a negative value.
1843 */
1844static int verify_lock(struct ref_lock *lock,
1845 const unsigned char *old_sha1, int mustexist,
1846 struct strbuf *err)
1847{
1848 assert(err);
1849
1850 if (read_ref_full(lock->ref_name,
1851 mustexist ? RESOLVE_REF_READING : 0,
1852 lock->old_oid.hash, NULL)) {
6294dcb4
JK
1853 if (old_sha1) {
1854 int save_errno = errno;
1855 strbuf_addf(err, "can't verify ref %s", lock->ref_name);
1856 errno = save_errno;
1857 return -1;
1858 } else {
1859 hashclr(lock->old_oid.hash);
1860 return 0;
1861 }
7bd9bcf3 1862 }
6294dcb4 1863 if (old_sha1 && hashcmp(lock->old_oid.hash, old_sha1)) {
7bd9bcf3
MH
1864 strbuf_addf(err, "ref %s is at %s but expected %s",
1865 lock->ref_name,
1866 sha1_to_hex(lock->old_oid.hash),
1867 sha1_to_hex(old_sha1));
1868 errno = EBUSY;
1869 return -1;
1870 }
1871 return 0;
1872}
1873
1874static int remove_empty_directories(struct strbuf *path)
1875{
1876 /*
1877 * we want to create a file but there is a directory there;
1878 * if that is an empty directory (or a directory that contains
1879 * only empty directories), remove them.
1880 */
1881 return remove_dir_recursively(path, REMOVE_DIR_EMPTY_ONLY);
1882}
1883
1884/*
1885 * Locks a ref returning the lock on success and NULL on failure.
1886 * On failure errno is set to something meaningful.
1887 */
1888static struct ref_lock *lock_ref_sha1_basic(const char *refname,
1889 const unsigned char *old_sha1,
1890 const struct string_list *extras,
1891 const struct string_list *skip,
1892 unsigned int flags, int *type_p,
1893 struct strbuf *err)
1894{
1895 struct strbuf ref_file = STRBUF_INIT;
1896 struct strbuf orig_ref_file = STRBUF_INIT;
1897 const char *orig_refname = refname;
1898 struct ref_lock *lock;
1899 int last_errno = 0;
2859dcd4
JK
1900 int type;
1901 int lflags = 0;
7bd9bcf3
MH
1902 int mustexist = (old_sha1 && !is_null_sha1(old_sha1));
1903 int resolve_flags = 0;
1904 int attempts_remaining = 3;
1905
1906 assert(err);
1907
1908 lock = xcalloc(1, sizeof(struct ref_lock));
1909
1910 if (mustexist)
1911 resolve_flags |= RESOLVE_REF_READING;
2859dcd4 1912 if (flags & REF_DELETING)
7bd9bcf3 1913 resolve_flags |= RESOLVE_REF_ALLOW_BAD_NAME;
2859dcd4
JK
1914 if (flags & REF_NODEREF) {
1915 resolve_flags |= RESOLVE_REF_NO_RECURSE;
1916 lflags |= LOCK_NO_DEREF;
7bd9bcf3
MH
1917 }
1918
1919 refname = resolve_ref_unsafe(refname, resolve_flags,
1920 lock->old_oid.hash, &type);
1921 if (!refname && errno == EISDIR) {
1922 /*
1923 * we are trying to lock foo but we used to
1924 * have foo/bar which now does not exist;
1925 * it is normal for the empty directory 'foo'
1926 * to remain.
1927 */
1928 strbuf_git_path(&orig_ref_file, "%s", orig_refname);
1929 if (remove_empty_directories(&orig_ref_file)) {
1930 last_errno = errno;
1931 if (!verify_refname_available_dir(orig_refname, extras, skip,
1932 get_loose_refs(&ref_cache), err))
1933 strbuf_addf(err, "there are still refs under '%s'",
1934 orig_refname);
1935 goto error_return;
1936 }
1937 refname = resolve_ref_unsafe(orig_refname, resolve_flags,
1938 lock->old_oid.hash, &type);
1939 }
1940 if (type_p)
1941 *type_p = type;
1942 if (!refname) {
1943 last_errno = errno;
1944 if (last_errno != ENOTDIR ||
1945 !verify_refname_available_dir(orig_refname, extras, skip,
1946 get_loose_refs(&ref_cache), err))
1947 strbuf_addf(err, "unable to resolve reference %s: %s",
1948 orig_refname, strerror(last_errno));
1949
1950 goto error_return;
1951 }
2859dcd4
JK
1952
1953 if (flags & REF_NODEREF)
1954 refname = orig_refname;
1955
7bd9bcf3
MH
1956 /*
1957 * If the ref did not exist and we are creating it, make sure
1958 * there is no existing packed ref whose name begins with our
1959 * refname, nor a packed ref whose name is a proper prefix of
1960 * our refname.
1961 */
1962 if (is_null_oid(&lock->old_oid) &&
1963 verify_refname_available_dir(refname, extras, skip,
1964 get_packed_refs(&ref_cache), err)) {
1965 last_errno = ENOTDIR;
1966 goto error_return;
1967 }
1968
1969 lock->lk = xcalloc(1, sizeof(struct lock_file));
1970
7bd9bcf3
MH
1971 lock->ref_name = xstrdup(refname);
1972 lock->orig_ref_name = xstrdup(orig_refname);
1973 strbuf_git_path(&ref_file, "%s", refname);
1974
1975 retry:
1976 switch (safe_create_leading_directories_const(ref_file.buf)) {
1977 case SCLD_OK:
1978 break; /* success */
1979 case SCLD_VANISHED:
1980 if (--attempts_remaining > 0)
1981 goto retry;
1982 /* fall through */
1983 default:
1984 last_errno = errno;
1985 strbuf_addf(err, "unable to create directory for %s",
1986 ref_file.buf);
1987 goto error_return;
1988 }
1989
1990 if (hold_lock_file_for_update(lock->lk, ref_file.buf, lflags) < 0) {
1991 last_errno = errno;
1992 if (errno == ENOENT && --attempts_remaining > 0)
1993 /*
1994 * Maybe somebody just deleted one of the
1995 * directories leading to ref_file. Try
1996 * again:
1997 */
1998 goto retry;
1999 else {
2000 unable_to_lock_message(ref_file.buf, errno, err);
2001 goto error_return;
2002 }
2003 }
6294dcb4 2004 if (verify_lock(lock, old_sha1, mustexist, err)) {
7bd9bcf3
MH
2005 last_errno = errno;
2006 goto error_return;
2007 }
2008 goto out;
2009
2010 error_return:
2011 unlock_ref(lock);
2012 lock = NULL;
2013
2014 out:
2015 strbuf_release(&ref_file);
2016 strbuf_release(&orig_ref_file);
2017 errno = last_errno;
2018 return lock;
2019}
2020
2021/*
2022 * Write an entry to the packed-refs file for the specified refname.
2023 * If peeled is non-NULL, write it as the entry's peeled value.
2024 */
2025static void write_packed_entry(FILE *fh, char *refname, unsigned char *sha1,
2026 unsigned char *peeled)
2027{
2028 fprintf_or_die(fh, "%s %s\n", sha1_to_hex(sha1), refname);
2029 if (peeled)
2030 fprintf_or_die(fh, "^%s\n", sha1_to_hex(peeled));
2031}
2032
2033/*
2034 * An each_ref_entry_fn that writes the entry to a packed-refs file.
2035 */
2036static int write_packed_entry_fn(struct ref_entry *entry, void *cb_data)
2037{
2038 enum peel_status peel_status = peel_entry(entry, 0);
2039
2040 if (peel_status != PEEL_PEELED && peel_status != PEEL_NON_TAG)
2041 error("internal error: %s is not a valid packed reference!",
2042 entry->name);
2043 write_packed_entry(cb_data, entry->name, entry->u.value.oid.hash,
2044 peel_status == PEEL_PEELED ?
2045 entry->u.value.peeled.hash : NULL);
2046 return 0;
2047}
2048
2049/*
2050 * Lock the packed-refs file for writing. Flags is passed to
2051 * hold_lock_file_for_update(). Return 0 on success. On errors, set
2052 * errno appropriately and return a nonzero value.
2053 */
2054static int lock_packed_refs(int flags)
2055{
2056 static int timeout_configured = 0;
2057 static int timeout_value = 1000;
2058
2059 struct packed_ref_cache *packed_ref_cache;
2060
2061 if (!timeout_configured) {
2062 git_config_get_int("core.packedrefstimeout", &timeout_value);
2063 timeout_configured = 1;
2064 }
2065
2066 if (hold_lock_file_for_update_timeout(
2067 &packlock, git_path("packed-refs"),
2068 flags, timeout_value) < 0)
2069 return -1;
2070 /*
2071 * Get the current packed-refs while holding the lock. If the
2072 * packed-refs file has been modified since we last read it,
2073 * this will automatically invalidate the cache and re-read
2074 * the packed-refs file.
2075 */
2076 packed_ref_cache = get_packed_ref_cache(&ref_cache);
2077 packed_ref_cache->lock = &packlock;
2078 /* Increment the reference count to prevent it from being freed: */
2079 acquire_packed_ref_cache(packed_ref_cache);
2080 return 0;
2081}
2082
2083/*
2084 * Write the current version of the packed refs cache from memory to
2085 * disk. The packed-refs file must already be locked for writing (see
2086 * lock_packed_refs()). Return zero on success. On errors, set errno
2087 * and return a nonzero value
2088 */
2089static int commit_packed_refs(void)
2090{
2091 struct packed_ref_cache *packed_ref_cache =
2092 get_packed_ref_cache(&ref_cache);
2093 int error = 0;
2094 int save_errno = 0;
2095 FILE *out;
2096
2097 if (!packed_ref_cache->lock)
2098 die("internal error: packed-refs not locked");
2099
2100 out = fdopen_lock_file(packed_ref_cache->lock, "w");
2101 if (!out)
2102 die_errno("unable to fdopen packed-refs descriptor");
2103
2104 fprintf_or_die(out, "%s", PACKED_REFS_HEADER);
2105 do_for_each_entry_in_dir(get_packed_ref_dir(packed_ref_cache),
2106 0, write_packed_entry_fn, out);
2107
2108 if (commit_lock_file(packed_ref_cache->lock)) {
2109 save_errno = errno;
2110 error = -1;
2111 }
2112 packed_ref_cache->lock = NULL;
2113 release_packed_ref_cache(packed_ref_cache);
2114 errno = save_errno;
2115 return error;
2116}
2117
2118/*
2119 * Rollback the lockfile for the packed-refs file, and discard the
2120 * in-memory packed reference cache. (The packed-refs file will be
2121 * read anew if it is needed again after this function is called.)
2122 */
2123static void rollback_packed_refs(void)
2124{
2125 struct packed_ref_cache *packed_ref_cache =
2126 get_packed_ref_cache(&ref_cache);
2127
2128 if (!packed_ref_cache->lock)
2129 die("internal error: packed-refs not locked");
2130 rollback_lock_file(packed_ref_cache->lock);
2131 packed_ref_cache->lock = NULL;
2132 release_packed_ref_cache(packed_ref_cache);
2133 clear_packed_ref_cache(&ref_cache);
2134}
2135
2136struct ref_to_prune {
2137 struct ref_to_prune *next;
2138 unsigned char sha1[20];
2139 char name[FLEX_ARRAY];
2140};
2141
2142struct pack_refs_cb_data {
2143 unsigned int flags;
2144 struct ref_dir *packed_refs;
2145 struct ref_to_prune *ref_to_prune;
2146};
2147
2148/*
2149 * An each_ref_entry_fn that is run over loose references only. If
2150 * the loose reference can be packed, add an entry in the packed ref
2151 * cache. If the reference should be pruned, also add it to
2152 * ref_to_prune in the pack_refs_cb_data.
2153 */
2154static int pack_if_possible_fn(struct ref_entry *entry, void *cb_data)
2155{
2156 struct pack_refs_cb_data *cb = cb_data;
2157 enum peel_status peel_status;
2158 struct ref_entry *packed_entry;
2159 int is_tag_ref = starts_with(entry->name, "refs/tags/");
2160
2161 /* Do not pack per-worktree refs: */
2162 if (ref_type(entry->name) != REF_TYPE_NORMAL)
2163 return 0;
2164
2165 /* ALWAYS pack tags */
2166 if (!(cb->flags & PACK_REFS_ALL) && !is_tag_ref)
2167 return 0;
2168
2169 /* Do not pack symbolic or broken refs: */
2170 if ((entry->flag & REF_ISSYMREF) || !ref_resolves_to_object(entry))
2171 return 0;
2172
2173 /* Add a packed ref cache entry equivalent to the loose entry. */
2174 peel_status = peel_entry(entry, 1);
2175 if (peel_status != PEEL_PEELED && peel_status != PEEL_NON_TAG)
2176 die("internal error peeling reference %s (%s)",
2177 entry->name, oid_to_hex(&entry->u.value.oid));
2178 packed_entry = find_ref(cb->packed_refs, entry->name);
2179 if (packed_entry) {
2180 /* Overwrite existing packed entry with info from loose entry */
2181 packed_entry->flag = REF_ISPACKED | REF_KNOWS_PEELED;
2182 oidcpy(&packed_entry->u.value.oid, &entry->u.value.oid);
2183 } else {
2184 packed_entry = create_ref_entry(entry->name, entry->u.value.oid.hash,
2185 REF_ISPACKED | REF_KNOWS_PEELED, 0);
2186 add_ref(cb->packed_refs, packed_entry);
2187 }
2188 oidcpy(&packed_entry->u.value.peeled, &entry->u.value.peeled);
2189
2190 /* Schedule the loose reference for pruning if requested. */
2191 if ((cb->flags & PACK_REFS_PRUNE)) {
96ffc06f
JK
2192 struct ref_to_prune *n;
2193 FLEX_ALLOC_STR(n, name, entry->name);
7bd9bcf3 2194 hashcpy(n->sha1, entry->u.value.oid.hash);
7bd9bcf3
MH
2195 n->next = cb->ref_to_prune;
2196 cb->ref_to_prune = n;
2197 }
2198 return 0;
2199}
2200
2201/*
2202 * Remove empty parents, but spare refs/ and immediate subdirs.
2203 * Note: munges *name.
2204 */
2205static void try_remove_empty_parents(char *name)
2206{
2207 char *p, *q;
2208 int i;
2209 p = name;
2210 for (i = 0; i < 2; i++) { /* refs/{heads,tags,...}/ */
2211 while (*p && *p != '/')
2212 p++;
2213 /* tolerate duplicate slashes; see check_refname_format() */
2214 while (*p == '/')
2215 p++;
2216 }
2217 for (q = p; *q; q++)
2218 ;
2219 while (1) {
2220 while (q > p && *q != '/')
2221 q--;
2222 while (q > p && *(q-1) == '/')
2223 q--;
2224 if (q == p)
2225 break;
2226 *q = '\0';
2227 if (rmdir(git_path("%s", name)))
2228 break;
2229 }
2230}
2231
2232/* make sure nobody touched the ref, and unlink */
2233static void prune_ref(struct ref_to_prune *r)
2234{
2235 struct ref_transaction *transaction;
2236 struct strbuf err = STRBUF_INIT;
2237
2238 if (check_refname_format(r->name, 0))
2239 return;
2240
2241 transaction = ref_transaction_begin(&err);
2242 if (!transaction ||
2243 ref_transaction_delete(transaction, r->name, r->sha1,
2244 REF_ISPRUNING, NULL, &err) ||
2245 ref_transaction_commit(transaction, &err)) {
2246 ref_transaction_free(transaction);
2247 error("%s", err.buf);
2248 strbuf_release(&err);
2249 return;
2250 }
2251 ref_transaction_free(transaction);
2252 strbuf_release(&err);
2253 try_remove_empty_parents(r->name);
2254}
2255
2256static void prune_refs(struct ref_to_prune *r)
2257{
2258 while (r) {
2259 prune_ref(r);
2260 r = r->next;
2261 }
2262}
2263
2264int pack_refs(unsigned int flags)
2265{
2266 struct pack_refs_cb_data cbdata;
2267
2268 memset(&cbdata, 0, sizeof(cbdata));
2269 cbdata.flags = flags;
2270
2271 lock_packed_refs(LOCK_DIE_ON_ERROR);
2272 cbdata.packed_refs = get_packed_refs(&ref_cache);
2273
2274 do_for_each_entry_in_dir(get_loose_refs(&ref_cache), 0,
2275 pack_if_possible_fn, &cbdata);
2276
2277 if (commit_packed_refs())
2278 die_errno("unable to overwrite old ref-pack file");
2279
2280 prune_refs(cbdata.ref_to_prune);
2281 return 0;
2282}
2283
2284/*
2285 * Rewrite the packed-refs file, omitting any refs listed in
2286 * 'refnames'. On error, leave packed-refs unchanged, write an error
2287 * message to 'err', and return a nonzero value.
2288 *
2289 * The refs in 'refnames' needn't be sorted. `err` must not be NULL.
2290 */
2291static int repack_without_refs(struct string_list *refnames, struct strbuf *err)
2292{
2293 struct ref_dir *packed;
2294 struct string_list_item *refname;
2295 int ret, needs_repacking = 0, removed = 0;
2296
2297 assert(err);
2298
2299 /* Look for a packed ref */
2300 for_each_string_list_item(refname, refnames) {
2301 if (get_packed_ref(refname->string)) {
2302 needs_repacking = 1;
2303 break;
2304 }
2305 }
2306
2307 /* Avoid locking if we have nothing to do */
2308 if (!needs_repacking)
2309 return 0; /* no refname exists in packed refs */
2310
2311 if (lock_packed_refs(0)) {
2312 unable_to_lock_message(git_path("packed-refs"), errno, err);
2313 return -1;
2314 }
2315 packed = get_packed_refs(&ref_cache);
2316
2317 /* Remove refnames from the cache */
2318 for_each_string_list_item(refname, refnames)
2319 if (remove_entry(packed, refname->string) != -1)
2320 removed = 1;
2321 if (!removed) {
2322 /*
2323 * All packed entries disappeared while we were
2324 * acquiring the lock.
2325 */
2326 rollback_packed_refs();
2327 return 0;
2328 }
2329
2330 /* Write what remains */
2331 ret = commit_packed_refs();
2332 if (ret)
2333 strbuf_addf(err, "unable to overwrite old ref-pack file: %s",
2334 strerror(errno));
2335 return ret;
2336}
2337
2338static int delete_ref_loose(struct ref_lock *lock, int flag, struct strbuf *err)
2339{
2340 assert(err);
2341
2342 if (!(flag & REF_ISPACKED) || flag & REF_ISSYMREF) {
2343 /*
2344 * loose. The loose file name is the same as the
2345 * lockfile name, minus ".lock":
2346 */
2347 char *loose_filename = get_locked_file_path(lock->lk);
2348 int res = unlink_or_msg(loose_filename, err);
2349 free(loose_filename);
2350 if (res)
2351 return 1;
2352 }
2353 return 0;
2354}
2355
2356int delete_refs(struct string_list *refnames)
2357{
2358 struct strbuf err = STRBUF_INIT;
2359 int i, result = 0;
2360
2361 if (!refnames->nr)
2362 return 0;
2363
2364 result = repack_without_refs(refnames, &err);
2365 if (result) {
2366 /*
2367 * If we failed to rewrite the packed-refs file, then
2368 * it is unsafe to try to remove loose refs, because
2369 * doing so might expose an obsolete packed value for
2370 * a reference that might even point at an object that
2371 * has been garbage collected.
2372 */
2373 if (refnames->nr == 1)
2374 error(_("could not delete reference %s: %s"),
2375 refnames->items[0].string, err.buf);
2376 else
2377 error(_("could not delete references: %s"), err.buf);
2378
2379 goto out;
2380 }
2381
2382 for (i = 0; i < refnames->nr; i++) {
2383 const char *refname = refnames->items[i].string;
2384
2385 if (delete_ref(refname, NULL, 0))
2386 result |= error(_("could not remove reference %s"), refname);
2387 }
2388
2389out:
2390 strbuf_release(&err);
2391 return result;
2392}
2393
2394/*
2395 * People using contrib's git-new-workdir have .git/logs/refs ->
2396 * /some/other/path/.git/logs/refs, and that may live on another device.
2397 *
2398 * IOW, to avoid cross device rename errors, the temporary renamed log must
2399 * live into logs/refs.
2400 */
2401#define TMP_RENAMED_LOG "logs/refs/.tmp-renamed-log"
2402
2403static int rename_tmp_log(const char *newrefname)
2404{
2405 int attempts_remaining = 4;
2406 struct strbuf path = STRBUF_INIT;
2407 int ret = -1;
2408
2409 retry:
2410 strbuf_reset(&path);
2411 strbuf_git_path(&path, "logs/%s", newrefname);
2412 switch (safe_create_leading_directories_const(path.buf)) {
2413 case SCLD_OK:
2414 break; /* success */
2415 case SCLD_VANISHED:
2416 if (--attempts_remaining > 0)
2417 goto retry;
2418 /* fall through */
2419 default:
2420 error("unable to create directory for %s", newrefname);
2421 goto out;
2422 }
2423
2424 if (rename(git_path(TMP_RENAMED_LOG), path.buf)) {
2425 if ((errno==EISDIR || errno==ENOTDIR) && --attempts_remaining > 0) {
2426 /*
2427 * rename(a, b) when b is an existing
2428 * directory ought to result in ISDIR, but
2429 * Solaris 5.8 gives ENOTDIR. Sheesh.
2430 */
2431 if (remove_empty_directories(&path)) {
2432 error("Directory not empty: logs/%s", newrefname);
2433 goto out;
2434 }
2435 goto retry;
2436 } else if (errno == ENOENT && --attempts_remaining > 0) {
2437 /*
2438 * Maybe another process just deleted one of
2439 * the directories in the path to newrefname.
2440 * Try again from the beginning.
2441 */
2442 goto retry;
2443 } else {
2444 error("unable to move logfile "TMP_RENAMED_LOG" to logs/%s: %s",
2445 newrefname, strerror(errno));
2446 goto out;
2447 }
2448 }
2449 ret = 0;
2450out:
2451 strbuf_release(&path);
2452 return ret;
2453}
2454
2455int verify_refname_available(const char *newname,
2456 struct string_list *extras,
2457 struct string_list *skip,
2458 struct strbuf *err)
2459{
2460 struct ref_dir *packed_refs = get_packed_refs(&ref_cache);
2461 struct ref_dir *loose_refs = get_loose_refs(&ref_cache);
2462
2463 if (verify_refname_available_dir(newname, extras, skip,
2464 packed_refs, err) ||
2465 verify_refname_available_dir(newname, extras, skip,
2466 loose_refs, err))
2467 return -1;
2468
2469 return 0;
2470}
2471
7bd9bcf3
MH
2472static int write_ref_to_lockfile(struct ref_lock *lock,
2473 const unsigned char *sha1, struct strbuf *err);
2474static int commit_ref_update(struct ref_lock *lock,
2475 const unsigned char *sha1, const char *logmsg,
2476 int flags, struct strbuf *err);
2477
2478int rename_ref(const char *oldrefname, const char *newrefname, const char *logmsg)
2479{
2480 unsigned char sha1[20], orig_sha1[20];
2481 int flag = 0, logmoved = 0;
2482 struct ref_lock *lock;
2483 struct stat loginfo;
2484 int log = !lstat(git_path("logs/%s", oldrefname), &loginfo);
2485 const char *symref = NULL;
2486 struct strbuf err = STRBUF_INIT;
2487
2488 if (log && S_ISLNK(loginfo.st_mode))
2489 return error("reflog for %s is a symlink", oldrefname);
2490
2491 symref = resolve_ref_unsafe(oldrefname, RESOLVE_REF_READING,
2492 orig_sha1, &flag);
2493 if (flag & REF_ISSYMREF)
2494 return error("refname %s is a symbolic ref, renaming it is not supported",
2495 oldrefname);
2496 if (!symref)
2497 return error("refname %s not found", oldrefname);
2498
2499 if (!rename_ref_available(oldrefname, newrefname))
2500 return 1;
2501
2502 if (log && rename(git_path("logs/%s", oldrefname), git_path(TMP_RENAMED_LOG)))
2503 return error("unable to move logfile logs/%s to "TMP_RENAMED_LOG": %s",
2504 oldrefname, strerror(errno));
2505
2506 if (delete_ref(oldrefname, orig_sha1, REF_NODEREF)) {
2507 error("unable to delete old %s", oldrefname);
2508 goto rollback;
2509 }
2510
2511 if (!read_ref_full(newrefname, RESOLVE_REF_READING, sha1, NULL) &&
2512 delete_ref(newrefname, sha1, REF_NODEREF)) {
2513 if (errno==EISDIR) {
2514 struct strbuf path = STRBUF_INIT;
2515 int result;
2516
2517 strbuf_git_path(&path, "%s", newrefname);
2518 result = remove_empty_directories(&path);
2519 strbuf_release(&path);
2520
2521 if (result) {
2522 error("Directory not empty: %s", newrefname);
2523 goto rollback;
2524 }
2525 } else {
2526 error("unable to delete existing %s", newrefname);
2527 goto rollback;
2528 }
2529 }
2530
2531 if (log && rename_tmp_log(newrefname))
2532 goto rollback;
2533
2534 logmoved = log;
2535
2536 lock = lock_ref_sha1_basic(newrefname, NULL, NULL, NULL, 0, NULL, &err);
2537 if (!lock) {
2538 error("unable to rename '%s' to '%s': %s", oldrefname, newrefname, err.buf);
2539 strbuf_release(&err);
2540 goto rollback;
2541 }
2542 hashcpy(lock->old_oid.hash, orig_sha1);
2543
2544 if (write_ref_to_lockfile(lock, orig_sha1, &err) ||
2545 commit_ref_update(lock, orig_sha1, logmsg, 0, &err)) {
2546 error("unable to write current sha1 into %s: %s", newrefname, err.buf);
2547 strbuf_release(&err);
2548 goto rollback;
2549 }
2550
2551 return 0;
2552
2553 rollback:
2554 lock = lock_ref_sha1_basic(oldrefname, NULL, NULL, NULL, 0, NULL, &err);
2555 if (!lock) {
2556 error("unable to lock %s for rollback: %s", oldrefname, err.buf);
2557 strbuf_release(&err);
2558 goto rollbacklog;
2559 }
2560
2561 flag = log_all_ref_updates;
2562 log_all_ref_updates = 0;
2563 if (write_ref_to_lockfile(lock, orig_sha1, &err) ||
2564 commit_ref_update(lock, orig_sha1, NULL, 0, &err)) {
2565 error("unable to write current sha1 into %s: %s", oldrefname, err.buf);
2566 strbuf_release(&err);
2567 }
2568 log_all_ref_updates = flag;
2569
2570 rollbacklog:
2571 if (logmoved && rename(git_path("logs/%s", newrefname), git_path("logs/%s", oldrefname)))
2572 error("unable to restore logfile %s from %s: %s",
2573 oldrefname, newrefname, strerror(errno));
2574 if (!logmoved && log &&
2575 rename(git_path(TMP_RENAMED_LOG), git_path("logs/%s", oldrefname)))
2576 error("unable to restore logfile %s from "TMP_RENAMED_LOG": %s",
2577 oldrefname, strerror(errno));
2578
2579 return 1;
2580}
2581
2582static int close_ref(struct ref_lock *lock)
2583{
2584 if (close_lock_file(lock->lk))
2585 return -1;
2586 return 0;
2587}
2588
2589static int commit_ref(struct ref_lock *lock)
2590{
2591 if (commit_lock_file(lock->lk))
2592 return -1;
2593 return 0;
2594}
2595
2596/*
2597 * Create a reflog for a ref. If force_create = 0, the reflog will
2598 * only be created for certain refs (those for which
2599 * should_autocreate_reflog returns non-zero. Otherwise, create it
2600 * regardless of the ref name. Fill in *err and return -1 on failure.
2601 */
2602static int log_ref_setup(const char *refname, struct strbuf *logfile, struct strbuf *err, int force_create)
2603{
2604 int logfd, oflags = O_APPEND | O_WRONLY;
2605
2606 strbuf_git_path(logfile, "logs/%s", refname);
2607 if (force_create || should_autocreate_reflog(refname)) {
2608 if (safe_create_leading_directories(logfile->buf) < 0) {
2609 strbuf_addf(err, "unable to create directory for %s: "
2610 "%s", logfile->buf, strerror(errno));
2611 return -1;
2612 }
2613 oflags |= O_CREAT;
2614 }
2615
2616 logfd = open(logfile->buf, oflags, 0666);
2617 if (logfd < 0) {
2618 if (!(oflags & O_CREAT) && (errno == ENOENT || errno == EISDIR))
2619 return 0;
2620
2621 if (errno == EISDIR) {
2622 if (remove_empty_directories(logfile)) {
2623 strbuf_addf(err, "There are still logs under "
2624 "'%s'", logfile->buf);
2625 return -1;
2626 }
2627 logfd = open(logfile->buf, oflags, 0666);
2628 }
2629
2630 if (logfd < 0) {
2631 strbuf_addf(err, "unable to append to %s: %s",
2632 logfile->buf, strerror(errno));
2633 return -1;
2634 }
2635 }
2636
2637 adjust_shared_perm(logfile->buf);
2638 close(logfd);
2639 return 0;
2640}
2641
2642
2643int safe_create_reflog(const char *refname, int force_create, struct strbuf *err)
2644{
2645 int ret;
2646 struct strbuf sb = STRBUF_INIT;
2647
2648 ret = log_ref_setup(refname, &sb, err, force_create);
2649 strbuf_release(&sb);
2650 return ret;
2651}
2652
2653static int log_ref_write_fd(int fd, const unsigned char *old_sha1,
2654 const unsigned char *new_sha1,
2655 const char *committer, const char *msg)
2656{
2657 int msglen, written;
2658 unsigned maxlen, len;
2659 char *logrec;
2660
2661 msglen = msg ? strlen(msg) : 0;
2662 maxlen = strlen(committer) + msglen + 100;
2663 logrec = xmalloc(maxlen);
2664 len = xsnprintf(logrec, maxlen, "%s %s %s\n",
2665 sha1_to_hex(old_sha1),
2666 sha1_to_hex(new_sha1),
2667 committer);
2668 if (msglen)
2669 len += copy_reflog_msg(logrec + len - 1, msg) - 1;
2670
2671 written = len <= maxlen ? write_in_full(fd, logrec, len) : -1;
2672 free(logrec);
2673 if (written != len)
2674 return -1;
2675
2676 return 0;
2677}
2678
2679static int log_ref_write_1(const char *refname, const unsigned char *old_sha1,
2680 const unsigned char *new_sha1, const char *msg,
2681 struct strbuf *logfile, int flags,
2682 struct strbuf *err)
2683{
2684 int logfd, result, oflags = O_APPEND | O_WRONLY;
2685
2686 if (log_all_ref_updates < 0)
2687 log_all_ref_updates = !is_bare_repository();
2688
2689 result = log_ref_setup(refname, logfile, err, flags & REF_FORCE_CREATE_REFLOG);
2690
2691 if (result)
2692 return result;
2693
2694 logfd = open(logfile->buf, oflags);
2695 if (logfd < 0)
2696 return 0;
2697 result = log_ref_write_fd(logfd, old_sha1, new_sha1,
2698 git_committer_info(0), msg);
2699 if (result) {
2700 strbuf_addf(err, "unable to append to %s: %s", logfile->buf,
2701 strerror(errno));
2702 close(logfd);
2703 return -1;
2704 }
2705 if (close(logfd)) {
2706 strbuf_addf(err, "unable to append to %s: %s", logfile->buf,
2707 strerror(errno));
2708 return -1;
2709 }
2710 return 0;
2711}
2712
2713static int log_ref_write(const char *refname, const unsigned char *old_sha1,
2714 const unsigned char *new_sha1, const char *msg,
2715 int flags, struct strbuf *err)
5f3c3a4e
DT
2716{
2717 return files_log_ref_write(refname, old_sha1, new_sha1, msg, flags,
2718 err);
2719}
2720
2721int files_log_ref_write(const char *refname, const unsigned char *old_sha1,
2722 const unsigned char *new_sha1, const char *msg,
2723 int flags, struct strbuf *err)
7bd9bcf3
MH
2724{
2725 struct strbuf sb = STRBUF_INIT;
2726 int ret = log_ref_write_1(refname, old_sha1, new_sha1, msg, &sb, flags,
2727 err);
2728 strbuf_release(&sb);
2729 return ret;
2730}
2731
2732/*
2733 * Write sha1 into the open lockfile, then close the lockfile. On
2734 * errors, rollback the lockfile, fill in *err and
2735 * return -1.
2736 */
2737static int write_ref_to_lockfile(struct ref_lock *lock,
2738 const unsigned char *sha1, struct strbuf *err)
2739{
2740 static char term = '\n';
2741 struct object *o;
2742 int fd;
2743
2744 o = parse_object(sha1);
2745 if (!o) {
2746 strbuf_addf(err,
2747 "Trying to write ref %s with nonexistent object %s",
2748 lock->ref_name, sha1_to_hex(sha1));
2749 unlock_ref(lock);
2750 return -1;
2751 }
2752 if (o->type != OBJ_COMMIT && is_branch(lock->ref_name)) {
2753 strbuf_addf(err,
2754 "Trying to write non-commit object %s to branch %s",
2755 sha1_to_hex(sha1), lock->ref_name);
2756 unlock_ref(lock);
2757 return -1;
2758 }
2759 fd = get_lock_file_fd(lock->lk);
2760 if (write_in_full(fd, sha1_to_hex(sha1), 40) != 40 ||
2761 write_in_full(fd, &term, 1) != 1 ||
2762 close_ref(lock) < 0) {
2763 strbuf_addf(err,
2764 "Couldn't write %s", get_lock_file_path(lock->lk));
2765 unlock_ref(lock);
2766 return -1;
2767 }
2768 return 0;
2769}
2770
2771/*
2772 * Commit a change to a loose reference that has already been written
2773 * to the loose reference lockfile. Also update the reflogs if
2774 * necessary, using the specified lockmsg (which can be NULL).
2775 */
2776static int commit_ref_update(struct ref_lock *lock,
2777 const unsigned char *sha1, const char *logmsg,
2778 int flags, struct strbuf *err)
2779{
2780 clear_loose_ref_cache(&ref_cache);
2781 if (log_ref_write(lock->ref_name, lock->old_oid.hash, sha1, logmsg, flags, err) < 0 ||
2782 (strcmp(lock->ref_name, lock->orig_ref_name) &&
2783 log_ref_write(lock->orig_ref_name, lock->old_oid.hash, sha1, logmsg, flags, err) < 0)) {
2784 char *old_msg = strbuf_detach(err, NULL);
2785 strbuf_addf(err, "Cannot update the ref '%s': %s",
2786 lock->ref_name, old_msg);
2787 free(old_msg);
2788 unlock_ref(lock);
2789 return -1;
2790 }
2791 if (strcmp(lock->orig_ref_name, "HEAD") != 0) {
2792 /*
2793 * Special hack: If a branch is updated directly and HEAD
2794 * points to it (may happen on the remote side of a push
2795 * for example) then logically the HEAD reflog should be
2796 * updated too.
2797 * A generic solution implies reverse symref information,
2798 * but finding all symrefs pointing to the given branch
2799 * would be rather costly for this rare event (the direct
2800 * update of a branch) to be worth it. So let's cheat and
2801 * check with HEAD only which should cover 99% of all usage
2802 * scenarios (even 100% of the default ones).
2803 */
2804 unsigned char head_sha1[20];
2805 int head_flag;
2806 const char *head_ref;
2807 head_ref = resolve_ref_unsafe("HEAD", RESOLVE_REF_READING,
2808 head_sha1, &head_flag);
2809 if (head_ref && (head_flag & REF_ISSYMREF) &&
2810 !strcmp(head_ref, lock->ref_name)) {
2811 struct strbuf log_err = STRBUF_INIT;
2812 if (log_ref_write("HEAD", lock->old_oid.hash, sha1,
2813 logmsg, 0, &log_err)) {
2814 error("%s", log_err.buf);
2815 strbuf_release(&log_err);
2816 }
2817 }
2818 }
2819 if (commit_ref(lock)) {
2820 error("Couldn't set %s", lock->ref_name);
2821 unlock_ref(lock);
2822 return -1;
2823 }
2824
2825 unlock_ref(lock);
2826 return 0;
2827}
2828
370e5ad6 2829static int create_ref_symlink(struct ref_lock *lock, const char *target)
7bd9bcf3 2830{
370e5ad6 2831 int ret = -1;
7bd9bcf3 2832#ifndef NO_SYMLINK_HEAD
370e5ad6
JK
2833 char *ref_path = get_locked_file_path(lock->lk);
2834 unlink(ref_path);
2835 ret = symlink(target, ref_path);
2836 free(ref_path);
2837
2838 if (ret)
7bd9bcf3 2839 fprintf(stderr, "no symlink - falling back to symbolic ref\n");
7bd9bcf3 2840#endif
370e5ad6
JK
2841 return ret;
2842}
7bd9bcf3 2843
370e5ad6
JK
2844static void update_symref_reflog(struct ref_lock *lock, const char *refname,
2845 const char *target, const char *logmsg)
2846{
2847 struct strbuf err = STRBUF_INIT;
2848 unsigned char new_sha1[20];
b9badadd 2849 if (logmsg && !read_ref(target, new_sha1) &&
370e5ad6 2850 log_ref_write(refname, lock->old_oid.hash, new_sha1, logmsg, 0, &err)) {
7bd9bcf3
MH
2851 error("%s", err.buf);
2852 strbuf_release(&err);
2853 }
370e5ad6 2854}
7bd9bcf3 2855
370e5ad6
JK
2856static int create_symref_locked(struct ref_lock *lock, const char *refname,
2857 const char *target, const char *logmsg)
2858{
2859 if (prefer_symlink_refs && !create_ref_symlink(lock, target)) {
2860 update_symref_reflog(lock, refname, target, logmsg);
2861 return 0;
2862 }
2863
2864 if (!fdopen_lock_file(lock->lk, "w"))
2865 return error("unable to fdopen %s: %s",
2866 lock->lk->tempfile.filename.buf, strerror(errno));
2867
396da8f7
JK
2868 update_symref_reflog(lock, refname, target, logmsg);
2869
370e5ad6
JK
2870 /* no error check; commit_ref will check ferror */
2871 fprintf(lock->lk->tempfile.fp, "ref: %s\n", target);
2872 if (commit_ref(lock) < 0)
2873 return error("unable to write symref for %s: %s", refname,
2874 strerror(errno));
7bd9bcf3
MH
2875 return 0;
2876}
2877
370e5ad6
JK
2878int create_symref(const char *refname, const char *target, const char *logmsg)
2879{
2880 struct strbuf err = STRBUF_INIT;
2881 struct ref_lock *lock;
2882 int ret;
2883
2884 lock = lock_ref_sha1_basic(refname, NULL, NULL, NULL, REF_NODEREF, NULL,
2885 &err);
2886 if (!lock) {
2887 error("%s", err.buf);
2888 strbuf_release(&err);
2889 return -1;
2890 }
2891
2892 ret = create_symref_locked(lock, refname, target, logmsg);
2893 unlock_ref(lock);
2894 return ret;
2895}
2896
7bd9bcf3
MH
2897int reflog_exists(const char *refname)
2898{
2899 struct stat st;
2900
2901 return !lstat(git_path("logs/%s", refname), &st) &&
2902 S_ISREG(st.st_mode);
2903}
2904
2905int delete_reflog(const char *refname)
2906{
2907 return remove_path(git_path("logs/%s", refname));
2908}
2909
2910static int show_one_reflog_ent(struct strbuf *sb, each_reflog_ent_fn fn, void *cb_data)
2911{
2912 unsigned char osha1[20], nsha1[20];
2913 char *email_end, *message;
2914 unsigned long timestamp;
2915 int tz;
2916
2917 /* old SP new SP name <email> SP time TAB msg LF */
2918 if (sb->len < 83 || sb->buf[sb->len - 1] != '\n' ||
2919 get_sha1_hex(sb->buf, osha1) || sb->buf[40] != ' ' ||
2920 get_sha1_hex(sb->buf + 41, nsha1) || sb->buf[81] != ' ' ||
2921 !(email_end = strchr(sb->buf + 82, '>')) ||
2922 email_end[1] != ' ' ||
2923 !(timestamp = strtoul(email_end + 2, &message, 10)) ||
2924 !message || message[0] != ' ' ||
2925 (message[1] != '+' && message[1] != '-') ||
2926 !isdigit(message[2]) || !isdigit(message[3]) ||
2927 !isdigit(message[4]) || !isdigit(message[5]))
2928 return 0; /* corrupt? */
2929 email_end[1] = '\0';
2930 tz = strtol(message + 1, NULL, 10);
2931 if (message[6] != '\t')
2932 message += 6;
2933 else
2934 message += 7;
2935 return fn(osha1, nsha1, sb->buf + 82, timestamp, tz, message, cb_data);
2936}
2937
2938static char *find_beginning_of_line(char *bob, char *scan)
2939{
2940 while (bob < scan && *(--scan) != '\n')
2941 ; /* keep scanning backwards */
2942 /*
2943 * Return either beginning of the buffer, or LF at the end of
2944 * the previous line.
2945 */
2946 return scan;
2947}
2948
2949int for_each_reflog_ent_reverse(const char *refname, each_reflog_ent_fn fn, void *cb_data)
2950{
2951 struct strbuf sb = STRBUF_INIT;
2952 FILE *logfp;
2953 long pos;
2954 int ret = 0, at_tail = 1;
2955
2956 logfp = fopen(git_path("logs/%s", refname), "r");
2957 if (!logfp)
2958 return -1;
2959
2960 /* Jump to the end */
2961 if (fseek(logfp, 0, SEEK_END) < 0)
2962 return error("cannot seek back reflog for %s: %s",
2963 refname, strerror(errno));
2964 pos = ftell(logfp);
2965 while (!ret && 0 < pos) {
2966 int cnt;
2967 size_t nread;
2968 char buf[BUFSIZ];
2969 char *endp, *scanp;
2970
2971 /* Fill next block from the end */
2972 cnt = (sizeof(buf) < pos) ? sizeof(buf) : pos;
2973 if (fseek(logfp, pos - cnt, SEEK_SET))
2974 return error("cannot seek back reflog for %s: %s",
2975 refname, strerror(errno));
2976 nread = fread(buf, cnt, 1, logfp);
2977 if (nread != 1)
2978 return error("cannot read %d bytes from reflog for %s: %s",
2979 cnt, refname, strerror(errno));
2980 pos -= cnt;
2981
2982 scanp = endp = buf + cnt;
2983 if (at_tail && scanp[-1] == '\n')
2984 /* Looking at the final LF at the end of the file */
2985 scanp--;
2986 at_tail = 0;
2987
2988 while (buf < scanp) {
2989 /*
2990 * terminating LF of the previous line, or the beginning
2991 * of the buffer.
2992 */
2993 char *bp;
2994
2995 bp = find_beginning_of_line(buf, scanp);
2996
2997 if (*bp == '\n') {
2998 /*
2999 * The newline is the end of the previous line,
3000 * so we know we have complete line starting
3001 * at (bp + 1). Prefix it onto any prior data
3002 * we collected for the line and process it.
3003 */
3004 strbuf_splice(&sb, 0, 0, bp + 1, endp - (bp + 1));
3005 scanp = bp;
3006 endp = bp + 1;
3007 ret = show_one_reflog_ent(&sb, fn, cb_data);
3008 strbuf_reset(&sb);
3009 if (ret)
3010 break;
3011 } else if (!pos) {
3012 /*
3013 * We are at the start of the buffer, and the
3014 * start of the file; there is no previous
3015 * line, and we have everything for this one.
3016 * Process it, and we can end the loop.
3017 */
3018 strbuf_splice(&sb, 0, 0, buf, endp - buf);
3019 ret = show_one_reflog_ent(&sb, fn, cb_data);
3020 strbuf_reset(&sb);
3021 break;
3022 }
3023
3024 if (bp == buf) {
3025 /*
3026 * We are at the start of the buffer, and there
3027 * is more file to read backwards. Which means
3028 * we are in the middle of a line. Note that we
3029 * may get here even if *bp was a newline; that
3030 * just means we are at the exact end of the
3031 * previous line, rather than some spot in the
3032 * middle.
3033 *
3034 * Save away what we have to be combined with
3035 * the data from the next read.
3036 */
3037 strbuf_splice(&sb, 0, 0, buf, endp - buf);
3038 break;
3039 }
3040 }
3041
3042 }
3043 if (!ret && sb.len)
3044 die("BUG: reverse reflog parser had leftover data");
3045
3046 fclose(logfp);
3047 strbuf_release(&sb);
3048 return ret;
3049}
3050
3051int for_each_reflog_ent(const char *refname, each_reflog_ent_fn fn, void *cb_data)
3052{
3053 FILE *logfp;
3054 struct strbuf sb = STRBUF_INIT;
3055 int ret = 0;
3056
3057 logfp = fopen(git_path("logs/%s", refname), "r");
3058 if (!logfp)
3059 return -1;
3060
3061 while (!ret && !strbuf_getwholeline(&sb, logfp, '\n'))
3062 ret = show_one_reflog_ent(&sb, fn, cb_data);
3063 fclose(logfp);
3064 strbuf_release(&sb);
3065 return ret;
3066}
3067/*
3068 * Call fn for each reflog in the namespace indicated by name. name
3069 * must be empty or end with '/'. Name will be used as a scratch
3070 * space, but its contents will be restored before return.
3071 */
3072static int do_for_each_reflog(struct strbuf *name, each_ref_fn fn, void *cb_data)
3073{
3074 DIR *d = opendir(git_path("logs/%s", name->buf));
3075 int retval = 0;
3076 struct dirent *de;
3077 int oldlen = name->len;
3078
3079 if (!d)
3080 return name->len ? errno : 0;
3081
3082 while ((de = readdir(d)) != NULL) {
3083 struct stat st;
3084
3085 if (de->d_name[0] == '.')
3086 continue;
3087 if (ends_with(de->d_name, ".lock"))
3088 continue;
3089 strbuf_addstr(name, de->d_name);
3090 if (stat(git_path("logs/%s", name->buf), &st) < 0) {
3091 ; /* silently ignore */
3092 } else {
3093 if (S_ISDIR(st.st_mode)) {
3094 strbuf_addch(name, '/');
3095 retval = do_for_each_reflog(name, fn, cb_data);
3096 } else {
3097 struct object_id oid;
3098
3099 if (read_ref_full(name->buf, 0, oid.hash, NULL))
3100 retval = error("bad ref for %s", name->buf);
3101 else
3102 retval = fn(name->buf, &oid, 0, cb_data);
3103 }
3104 if (retval)
3105 break;
3106 }
3107 strbuf_setlen(name, oldlen);
3108 }
3109 closedir(d);
3110 return retval;
3111}
3112
3113int for_each_reflog(each_ref_fn fn, void *cb_data)
3114{
3115 int retval;
3116 struct strbuf name;
3117 strbuf_init(&name, PATH_MAX);
3118 retval = do_for_each_reflog(&name, fn, cb_data);
3119 strbuf_release(&name);
3120 return retval;
3121}
3122
3123static int ref_update_reject_duplicates(struct string_list *refnames,
3124 struct strbuf *err)
3125{
3126 int i, n = refnames->nr;
3127
3128 assert(err);
3129
3130 for (i = 1; i < n; i++)
3131 if (!strcmp(refnames->items[i - 1].string, refnames->items[i].string)) {
3132 strbuf_addf(err,
3133 "Multiple updates for ref '%s' not allowed.",
3134 refnames->items[i].string);
3135 return 1;
3136 }
3137 return 0;
3138}
3139
3140int ref_transaction_commit(struct ref_transaction *transaction,
3141 struct strbuf *err)
3142{
3143 int ret = 0, i;
3144 int n = transaction->nr;
3145 struct ref_update **updates = transaction->updates;
3146 struct string_list refs_to_delete = STRING_LIST_INIT_NODUP;
3147 struct string_list_item *ref_to_delete;
3148 struct string_list affected_refnames = STRING_LIST_INIT_NODUP;
3149
3150 assert(err);
3151
3152 if (transaction->state != REF_TRANSACTION_OPEN)
3153 die("BUG: commit called for transaction that is not open");
3154
3155 if (!n) {
3156 transaction->state = REF_TRANSACTION_CLOSED;
3157 return 0;
3158 }
3159
3160 /* Fail if a refname appears more than once in the transaction: */
3161 for (i = 0; i < n; i++)
3162 string_list_append(&affected_refnames, updates[i]->refname);
3163 string_list_sort(&affected_refnames);
3164 if (ref_update_reject_duplicates(&affected_refnames, err)) {
3165 ret = TRANSACTION_GENERIC_ERROR;
3166 goto cleanup;
3167 }
3168
3169 /*
3170 * Acquire all locks, verify old values if provided, check
3171 * that new values are valid, and write new values to the
3172 * lockfiles, ready to be activated. Only keep one lockfile
3173 * open at a time to avoid running out of file descriptors.
3174 */
3175 for (i = 0; i < n; i++) {
3176 struct ref_update *update = updates[i];
3177
3178 if ((update->flags & REF_HAVE_NEW) &&
3179 is_null_sha1(update->new_sha1))
3180 update->flags |= REF_DELETING;
3181 update->lock = lock_ref_sha1_basic(
3182 update->refname,
3183 ((update->flags & REF_HAVE_OLD) ?
3184 update->old_sha1 : NULL),
3185 &affected_refnames, NULL,
3186 update->flags,
3187 &update->type,
3188 err);
3189 if (!update->lock) {
3190 char *reason;
3191
3192 ret = (errno == ENOTDIR)
3193 ? TRANSACTION_NAME_CONFLICT
3194 : TRANSACTION_GENERIC_ERROR;
3195 reason = strbuf_detach(err, NULL);
3196 strbuf_addf(err, "cannot lock ref '%s': %s",
3197 update->refname, reason);
3198 free(reason);
3199 goto cleanup;
3200 }
3201 if ((update->flags & REF_HAVE_NEW) &&
3202 !(update->flags & REF_DELETING)) {
3203 int overwriting_symref = ((update->type & REF_ISSYMREF) &&
3204 (update->flags & REF_NODEREF));
3205
3206 if (!overwriting_symref &&
3207 !hashcmp(update->lock->old_oid.hash, update->new_sha1)) {
3208 /*
3209 * The reference already has the desired
3210 * value, so we don't need to write it.
3211 */
3212 } else if (write_ref_to_lockfile(update->lock,
3213 update->new_sha1,
3214 err)) {
3215 char *write_err = strbuf_detach(err, NULL);
3216
3217 /*
3218 * The lock was freed upon failure of
3219 * write_ref_to_lockfile():
3220 */
3221 update->lock = NULL;
3222 strbuf_addf(err,
3223 "cannot update the ref '%s': %s",
3224 update->refname, write_err);
3225 free(write_err);
3226 ret = TRANSACTION_GENERIC_ERROR;
3227 goto cleanup;
3228 } else {
3229 update->flags |= REF_NEEDS_COMMIT;
3230 }
3231 }
3232 if (!(update->flags & REF_NEEDS_COMMIT)) {
3233 /*
3234 * We didn't have to write anything to the lockfile.
3235 * Close it to free up the file descriptor:
3236 */
3237 if (close_ref(update->lock)) {
3238 strbuf_addf(err, "Couldn't close %s.lock",
3239 update->refname);
3240 goto cleanup;
3241 }
3242 }
3243 }
3244
3245 /* Perform updates first so live commits remain referenced */
3246 for (i = 0; i < n; i++) {
3247 struct ref_update *update = updates[i];
3248
3249 if (update->flags & REF_NEEDS_COMMIT) {
3250 if (commit_ref_update(update->lock,
3251 update->new_sha1, update->msg,
3252 update->flags, err)) {
3253 /* freed by commit_ref_update(): */
3254 update->lock = NULL;
3255 ret = TRANSACTION_GENERIC_ERROR;
3256 goto cleanup;
3257 } else {
3258 /* freed by commit_ref_update(): */
3259 update->lock = NULL;
3260 }
3261 }
3262 }
3263
3264 /* Perform deletes now that updates are safely completed */
3265 for (i = 0; i < n; i++) {
3266 struct ref_update *update = updates[i];
3267
3268 if (update->flags & REF_DELETING) {
3269 if (delete_ref_loose(update->lock, update->type, err)) {
3270 ret = TRANSACTION_GENERIC_ERROR;
3271 goto cleanup;
3272 }
3273
3274 if (!(update->flags & REF_ISPRUNING))
3275 string_list_append(&refs_to_delete,
3276 update->lock->ref_name);
3277 }
3278 }
3279
3280 if (repack_without_refs(&refs_to_delete, err)) {
3281 ret = TRANSACTION_GENERIC_ERROR;
3282 goto cleanup;
3283 }
3284 for_each_string_list_item(ref_to_delete, &refs_to_delete)
3285 unlink_or_warn(git_path("logs/%s", ref_to_delete->string));
3286 clear_loose_ref_cache(&ref_cache);
3287
3288cleanup:
3289 transaction->state = REF_TRANSACTION_CLOSED;
3290
3291 for (i = 0; i < n; i++)
3292 if (updates[i]->lock)
3293 unlock_ref(updates[i]->lock);
3294 string_list_clear(&refs_to_delete, 0);
3295 string_list_clear(&affected_refnames, 0);
3296 return ret;
3297}
3298
3299static int ref_present(const char *refname,
3300 const struct object_id *oid, int flags, void *cb_data)
3301{
3302 struct string_list *affected_refnames = cb_data;
3303
3304 return string_list_has_string(affected_refnames, refname);
3305}
3306
3307int initial_ref_transaction_commit(struct ref_transaction *transaction,
3308 struct strbuf *err)
3309{
3310 int ret = 0, i;
3311 int n = transaction->nr;
3312 struct ref_update **updates = transaction->updates;
3313 struct string_list affected_refnames = STRING_LIST_INIT_NODUP;
3314
3315 assert(err);
3316
3317 if (transaction->state != REF_TRANSACTION_OPEN)
3318 die("BUG: commit called for transaction that is not open");
3319
3320 /* Fail if a refname appears more than once in the transaction: */
3321 for (i = 0; i < n; i++)
3322 string_list_append(&affected_refnames, updates[i]->refname);
3323 string_list_sort(&affected_refnames);
3324 if (ref_update_reject_duplicates(&affected_refnames, err)) {
3325 ret = TRANSACTION_GENERIC_ERROR;
3326 goto cleanup;
3327 }
3328
3329 /*
3330 * It's really undefined to call this function in an active
3331 * repository or when there are existing references: we are
3332 * only locking and changing packed-refs, so (1) any
3333 * simultaneous processes might try to change a reference at
3334 * the same time we do, and (2) any existing loose versions of
3335 * the references that we are setting would have precedence
3336 * over our values. But some remote helpers create the remote
3337 * "HEAD" and "master" branches before calling this function,
3338 * so here we really only check that none of the references
3339 * that we are creating already exists.
3340 */
3341 if (for_each_rawref(ref_present, &affected_refnames))
3342 die("BUG: initial ref transaction called with existing refs");
3343
3344 for (i = 0; i < n; i++) {
3345 struct ref_update *update = updates[i];
3346
3347 if ((update->flags & REF_HAVE_OLD) &&
3348 !is_null_sha1(update->old_sha1))
3349 die("BUG: initial ref transaction with old_sha1 set");
3350 if (verify_refname_available(update->refname,
3351 &affected_refnames, NULL,
3352 err)) {
3353 ret = TRANSACTION_NAME_CONFLICT;
3354 goto cleanup;
3355 }
3356 }
3357
3358 if (lock_packed_refs(0)) {
3359 strbuf_addf(err, "unable to lock packed-refs file: %s",
3360 strerror(errno));
3361 ret = TRANSACTION_GENERIC_ERROR;
3362 goto cleanup;
3363 }
3364
3365 for (i = 0; i < n; i++) {
3366 struct ref_update *update = updates[i];
3367
3368 if ((update->flags & REF_HAVE_NEW) &&
3369 !is_null_sha1(update->new_sha1))
3370 add_packed_ref(update->refname, update->new_sha1);
3371 }
3372
3373 if (commit_packed_refs()) {
3374 strbuf_addf(err, "unable to commit packed-refs file: %s",
3375 strerror(errno));
3376 ret = TRANSACTION_GENERIC_ERROR;
3377 goto cleanup;
3378 }
3379
3380cleanup:
3381 transaction->state = REF_TRANSACTION_CLOSED;
3382 string_list_clear(&affected_refnames, 0);
3383 return ret;
3384}
3385
3386struct expire_reflog_cb {
3387 unsigned int flags;
3388 reflog_expiry_should_prune_fn *should_prune_fn;
3389 void *policy_cb;
3390 FILE *newlog;
3391 unsigned char last_kept_sha1[20];
3392};
3393
3394static int expire_reflog_ent(unsigned char *osha1, unsigned char *nsha1,
3395 const char *email, unsigned long timestamp, int tz,
3396 const char *message, void *cb_data)
3397{
3398 struct expire_reflog_cb *cb = cb_data;
3399 struct expire_reflog_policy_cb *policy_cb = cb->policy_cb;
3400
3401 if (cb->flags & EXPIRE_REFLOGS_REWRITE)
3402 osha1 = cb->last_kept_sha1;
3403
3404 if ((*cb->should_prune_fn)(osha1, nsha1, email, timestamp, tz,
3405 message, policy_cb)) {
3406 if (!cb->newlog)
3407 printf("would prune %s", message);
3408 else if (cb->flags & EXPIRE_REFLOGS_VERBOSE)
3409 printf("prune %s", message);
3410 } else {
3411 if (cb->newlog) {
3412 fprintf(cb->newlog, "%s %s %s %lu %+05d\t%s",
3413 sha1_to_hex(osha1), sha1_to_hex(nsha1),
3414 email, timestamp, tz, message);
3415 hashcpy(cb->last_kept_sha1, nsha1);
3416 }
3417 if (cb->flags & EXPIRE_REFLOGS_VERBOSE)
3418 printf("keep %s", message);
3419 }
3420 return 0;
3421}
3422
3423int reflog_expire(const char *refname, const unsigned char *sha1,
3424 unsigned int flags,
3425 reflog_expiry_prepare_fn prepare_fn,
3426 reflog_expiry_should_prune_fn should_prune_fn,
3427 reflog_expiry_cleanup_fn cleanup_fn,
3428 void *policy_cb_data)
3429{
3430 static struct lock_file reflog_lock;
3431 struct expire_reflog_cb cb;
3432 struct ref_lock *lock;
3433 char *log_file;
3434 int status = 0;
3435 int type;
3436 struct strbuf err = STRBUF_INIT;
3437
3438 memset(&cb, 0, sizeof(cb));
3439 cb.flags = flags;
3440 cb.policy_cb = policy_cb_data;
3441 cb.should_prune_fn = should_prune_fn;
3442
3443 /*
3444 * The reflog file is locked by holding the lock on the
3445 * reference itself, plus we might need to update the
3446 * reference if --updateref was specified:
3447 */
3448 lock = lock_ref_sha1_basic(refname, sha1, NULL, NULL, 0, &type, &err);
3449 if (!lock) {
3450 error("cannot lock ref '%s': %s", refname, err.buf);
3451 strbuf_release(&err);
3452 return -1;
3453 }
3454 if (!reflog_exists(refname)) {
3455 unlock_ref(lock);
3456 return 0;
3457 }
3458
3459 log_file = git_pathdup("logs/%s", refname);
3460 if (!(flags & EXPIRE_REFLOGS_DRY_RUN)) {
3461 /*
3462 * Even though holding $GIT_DIR/logs/$reflog.lock has
3463 * no locking implications, we use the lock_file
3464 * machinery here anyway because it does a lot of the
3465 * work we need, including cleaning up if the program
3466 * exits unexpectedly.
3467 */
3468 if (hold_lock_file_for_update(&reflog_lock, log_file, 0) < 0) {
3469 struct strbuf err = STRBUF_INIT;
3470 unable_to_lock_message(log_file, errno, &err);
3471 error("%s", err.buf);
3472 strbuf_release(&err);
3473 goto failure;
3474 }
3475 cb.newlog = fdopen_lock_file(&reflog_lock, "w");
3476 if (!cb.newlog) {
3477 error("cannot fdopen %s (%s)",
3478 get_lock_file_path(&reflog_lock), strerror(errno));
3479 goto failure;
3480 }
3481 }
3482
3483 (*prepare_fn)(refname, sha1, cb.policy_cb);
3484 for_each_reflog_ent(refname, expire_reflog_ent, &cb);
3485 (*cleanup_fn)(cb.policy_cb);
3486
3487 if (!(flags & EXPIRE_REFLOGS_DRY_RUN)) {
3488 /*
3489 * It doesn't make sense to adjust a reference pointed
3490 * to by a symbolic ref based on expiring entries in
3491 * the symbolic reference's reflog. Nor can we update
3492 * a reference if there are no remaining reflog
3493 * entries.
3494 */
3495 int update = (flags & EXPIRE_REFLOGS_UPDATE_REF) &&
3496 !(type & REF_ISSYMREF) &&
3497 !is_null_sha1(cb.last_kept_sha1);
3498
3499 if (close_lock_file(&reflog_lock)) {
3500 status |= error("couldn't write %s: %s", log_file,
3501 strerror(errno));
3502 } else if (update &&
3503 (write_in_full(get_lock_file_fd(lock->lk),
3504 sha1_to_hex(cb.last_kept_sha1), 40) != 40 ||
3505 write_str_in_full(get_lock_file_fd(lock->lk), "\n") != 1 ||
3506 close_ref(lock) < 0)) {
3507 status |= error("couldn't write %s",
3508 get_lock_file_path(lock->lk));
3509 rollback_lock_file(&reflog_lock);
3510 } else if (commit_lock_file(&reflog_lock)) {
e0048d3e 3511 status |= error("unable to write reflog '%s' (%s)",
7bd9bcf3
MH
3512 log_file, strerror(errno));
3513 } else if (update && commit_ref(lock)) {
3514 status |= error("couldn't set %s", lock->ref_name);
3515 }
3516 }
3517 free(log_file);
3518 unlock_ref(lock);
3519 return status;
3520
3521 failure:
3522 rollback_lock_file(&reflog_lock);
3523 free(log_file);
3524 unlock_ref(lock);
3525 return -1;
3526}