use xmallocz to avoid size arithmetic
[git/git.git] / refs / files-backend.c
CommitLineData
7bd9bcf3
MH
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{
202 int len;
203 struct ref_entry *ref;
204
205 if (check_name &&
206 check_refname_format(refname, REFNAME_ALLOW_ONELEVEL))
207 die("Reference has invalid format: '%s'", refname);
208 len = strlen(refname) + 1;
209 ref = xmalloc(sizeof(struct ref_entry) + len);
210 hashcpy(ref->u.value.oid.hash, sha1);
211 oidclr(&ref->u.value.peeled);
212 memcpy(ref->name, refname, len);
213 ref->flag = flag;
214 return ref;
215}
216
217static void clear_ref_dir(struct ref_dir *dir);
218
219static void free_ref_entry(struct ref_entry *entry)
220{
221 if (entry->flag & REF_DIR) {
222 /*
223 * Do not use get_ref_dir() here, as that might
224 * trigger the reading of loose refs.
225 */
226 clear_ref_dir(&entry->u.subdir);
227 }
228 free(entry);
229}
230
231/*
232 * Add a ref_entry to the end of dir (unsorted). Entry is always
233 * stored directly in dir; no recursion into subdirectories is
234 * done.
235 */
236static void add_entry_to_dir(struct ref_dir *dir, struct ref_entry *entry)
237{
238 ALLOC_GROW(dir->entries, dir->nr + 1, dir->alloc);
239 dir->entries[dir->nr++] = entry;
240 /* optimize for the case that entries are added in order */
241 if (dir->nr == 1 ||
242 (dir->nr == dir->sorted + 1 &&
243 strcmp(dir->entries[dir->nr - 2]->name,
244 dir->entries[dir->nr - 1]->name) < 0))
245 dir->sorted = dir->nr;
246}
247
248/*
249 * Clear and free all entries in dir, recursively.
250 */
251static void clear_ref_dir(struct ref_dir *dir)
252{
253 int i;
254 for (i = 0; i < dir->nr; i++)
255 free_ref_entry(dir->entries[i]);
256 free(dir->entries);
257 dir->sorted = dir->nr = dir->alloc = 0;
258 dir->entries = NULL;
259}
260
261/*
262 * Create a struct ref_entry object for the specified dirname.
263 * dirname is the name of the directory with a trailing slash (e.g.,
264 * "refs/heads/") or "" for the top-level directory.
265 */
266static struct ref_entry *create_dir_entry(struct ref_cache *ref_cache,
267 const char *dirname, size_t len,
268 int incomplete)
269{
270 struct ref_entry *direntry;
271 direntry = xcalloc(1, sizeof(struct ref_entry) + len + 1);
272 memcpy(direntry->name, dirname, len);
273 direntry->name[len] = '\0';
274 direntry->u.subdir.ref_cache = ref_cache;
275 direntry->flag = REF_DIR | (incomplete ? REF_INCOMPLETE : 0);
276 return direntry;
277}
278
279static int ref_entry_cmp(const void *a, const void *b)
280{
281 struct ref_entry *one = *(struct ref_entry **)a;
282 struct ref_entry *two = *(struct ref_entry **)b;
283 return strcmp(one->name, two->name);
284}
285
286static void sort_ref_dir(struct ref_dir *dir);
287
288struct string_slice {
289 size_t len;
290 const char *str;
291};
292
293static int ref_entry_cmp_sslice(const void *key_, const void *ent_)
294{
295 const struct string_slice *key = key_;
296 const struct ref_entry *ent = *(const struct ref_entry * const *)ent_;
297 int cmp = strncmp(key->str, ent->name, key->len);
298 if (cmp)
299 return cmp;
300 return '\0' - (unsigned char)ent->name[key->len];
301}
302
303/*
304 * Return the index of the entry with the given refname from the
305 * ref_dir (non-recursively), sorting dir if necessary. Return -1 if
306 * no such entry is found. dir must already be complete.
307 */
308static int search_ref_dir(struct ref_dir *dir, const char *refname, size_t len)
309{
310 struct ref_entry **r;
311 struct string_slice key;
312
313 if (refname == NULL || !dir->nr)
314 return -1;
315
316 sort_ref_dir(dir);
317 key.len = len;
318 key.str = refname;
319 r = bsearch(&key, dir->entries, dir->nr, sizeof(*dir->entries),
320 ref_entry_cmp_sslice);
321
322 if (r == NULL)
323 return -1;
324
325 return r - dir->entries;
326}
327
328/*
329 * Search for a directory entry directly within dir (without
330 * recursing). Sort dir if necessary. subdirname must be a directory
331 * name (i.e., end in '/'). If mkdir is set, then create the
332 * directory if it is missing; otherwise, return NULL if the desired
333 * directory cannot be found. dir must already be complete.
334 */
335static struct ref_dir *search_for_subdir(struct ref_dir *dir,
336 const char *subdirname, size_t len,
337 int mkdir)
338{
339 int entry_index = search_ref_dir(dir, subdirname, len);
340 struct ref_entry *entry;
341 if (entry_index == -1) {
342 if (!mkdir)
343 return NULL;
344 /*
345 * Since dir is complete, the absence of a subdir
346 * means that the subdir really doesn't exist;
347 * therefore, create an empty record for it but mark
348 * the record complete.
349 */
350 entry = create_dir_entry(dir->ref_cache, subdirname, len, 0);
351 add_entry_to_dir(dir, entry);
352 } else {
353 entry = dir->entries[entry_index];
354 }
355 return get_ref_dir(entry);
356}
357
358/*
359 * If refname is a reference name, find the ref_dir within the dir
360 * tree that should hold refname. If refname is a directory name
361 * (i.e., ends in '/'), then return that ref_dir itself. dir must
362 * represent the top-level directory and must already be complete.
363 * Sort ref_dirs and recurse into subdirectories as necessary. If
364 * mkdir is set, then create any missing directories; otherwise,
365 * return NULL if the desired directory cannot be found.
366 */
367static struct ref_dir *find_containing_dir(struct ref_dir *dir,
368 const char *refname, int mkdir)
369{
370 const char *slash;
371 for (slash = strchr(refname, '/'); slash; slash = strchr(slash + 1, '/')) {
372 size_t dirnamelen = slash - refname + 1;
373 struct ref_dir *subdir;
374 subdir = search_for_subdir(dir, refname, dirnamelen, mkdir);
375 if (!subdir) {
376 dir = NULL;
377 break;
378 }
379 dir = subdir;
380 }
381
382 return dir;
383}
384
385/*
386 * Find the value entry with the given name in dir, sorting ref_dirs
387 * and recursing into subdirectories as necessary. If the name is not
388 * found or it corresponds to a directory entry, return NULL.
389 */
390static struct ref_entry *find_ref(struct ref_dir *dir, const char *refname)
391{
392 int entry_index;
393 struct ref_entry *entry;
394 dir = find_containing_dir(dir, refname, 0);
395 if (!dir)
396 return NULL;
397 entry_index = search_ref_dir(dir, refname, strlen(refname));
398 if (entry_index == -1)
399 return NULL;
400 entry = dir->entries[entry_index];
401 return (entry->flag & REF_DIR) ? NULL : entry;
402}
403
404/*
405 * Remove the entry with the given name from dir, recursing into
406 * subdirectories as necessary. If refname is the name of a directory
407 * (i.e., ends with '/'), then remove the directory and its contents.
408 * If the removal was successful, return the number of entries
409 * remaining in the directory entry that contained the deleted entry.
410 * If the name was not found, return -1. Please note that this
411 * function only deletes the entry from the cache; it does not delete
412 * it from the filesystem or ensure that other cache entries (which
413 * might be symbolic references to the removed entry) are updated.
414 * Nor does it remove any containing dir entries that might be made
415 * empty by the removal. dir must represent the top-level directory
416 * and must already be complete.
417 */
418static int remove_entry(struct ref_dir *dir, const char *refname)
419{
420 int refname_len = strlen(refname);
421 int entry_index;
422 struct ref_entry *entry;
423 int is_dir = refname[refname_len - 1] == '/';
424 if (is_dir) {
425 /*
426 * refname represents a reference directory. Remove
427 * the trailing slash; otherwise we will get the
428 * directory *representing* refname rather than the
429 * one *containing* it.
430 */
431 char *dirname = xmemdupz(refname, refname_len - 1);
432 dir = find_containing_dir(dir, dirname, 0);
433 free(dirname);
434 } else {
435 dir = find_containing_dir(dir, refname, 0);
436 }
437 if (!dir)
438 return -1;
439 entry_index = search_ref_dir(dir, refname, refname_len);
440 if (entry_index == -1)
441 return -1;
442 entry = dir->entries[entry_index];
443
444 memmove(&dir->entries[entry_index],
445 &dir->entries[entry_index + 1],
446 (dir->nr - entry_index - 1) * sizeof(*dir->entries)
447 );
448 dir->nr--;
449 if (dir->sorted > entry_index)
450 dir->sorted--;
451 free_ref_entry(entry);
452 return dir->nr;
453}
454
455/*
456 * Add a ref_entry to the ref_dir (unsorted), recursing into
457 * subdirectories as necessary. dir must represent the top-level
458 * directory. Return 0 on success.
459 */
460static int add_ref(struct ref_dir *dir, struct ref_entry *ref)
461{
462 dir = find_containing_dir(dir, ref->name, 1);
463 if (!dir)
464 return -1;
465 add_entry_to_dir(dir, ref);
466 return 0;
467}
468
469/*
470 * Emit a warning and return true iff ref1 and ref2 have the same name
471 * and the same sha1. Die if they have the same name but different
472 * sha1s.
473 */
474static int is_dup_ref(const struct ref_entry *ref1, const struct ref_entry *ref2)
475{
476 if (strcmp(ref1->name, ref2->name))
477 return 0;
478
479 /* Duplicate name; make sure that they don't conflict: */
480
481 if ((ref1->flag & REF_DIR) || (ref2->flag & REF_DIR))
482 /* This is impossible by construction */
483 die("Reference directory conflict: %s", ref1->name);
484
485 if (oidcmp(&ref1->u.value.oid, &ref2->u.value.oid))
486 die("Duplicated ref, and SHA1s don't match: %s", ref1->name);
487
488 warning("Duplicated ref: %s", ref1->name);
489 return 1;
490}
491
492/*
493 * Sort the entries in dir non-recursively (if they are not already
494 * sorted) and remove any duplicate entries.
495 */
496static void sort_ref_dir(struct ref_dir *dir)
497{
498 int i, j;
499 struct ref_entry *last = NULL;
500
501 /*
502 * This check also prevents passing a zero-length array to qsort(),
503 * which is a problem on some platforms.
504 */
505 if (dir->sorted == dir->nr)
506 return;
507
508 qsort(dir->entries, dir->nr, sizeof(*dir->entries), ref_entry_cmp);
509
510 /* Remove any duplicates: */
511 for (i = 0, j = 0; j < dir->nr; j++) {
512 struct ref_entry *entry = dir->entries[j];
513 if (last && is_dup_ref(last, entry))
514 free_ref_entry(entry);
515 else
516 last = dir->entries[i++] = entry;
517 }
518 dir->sorted = dir->nr = i;
519}
520
521/* Include broken references in a do_for_each_ref*() iteration: */
522#define DO_FOR_EACH_INCLUDE_BROKEN 0x01
523
524/*
525 * Return true iff the reference described by entry can be resolved to
526 * an object in the database. Emit a warning if the referred-to
527 * object does not exist.
528 */
529static int ref_resolves_to_object(struct ref_entry *entry)
530{
531 if (entry->flag & REF_ISBROKEN)
532 return 0;
533 if (!has_sha1_file(entry->u.value.oid.hash)) {
534 error("%s does not point to a valid object!", entry->name);
535 return 0;
536 }
537 return 1;
538}
539
540/*
541 * current_ref is a performance hack: when iterating over references
542 * using the for_each_ref*() functions, current_ref is set to the
543 * current reference's entry before calling the callback function. If
544 * the callback function calls peel_ref(), then peel_ref() first
545 * checks whether the reference to be peeled is the current reference
546 * (it usually is) and if so, returns that reference's peeled version
547 * if it is available. This avoids a refname lookup in a common case.
548 */
549static struct ref_entry *current_ref;
550
551typedef int each_ref_entry_fn(struct ref_entry *entry, void *cb_data);
552
553struct ref_entry_cb {
554 const char *base;
555 int trim;
556 int flags;
557 each_ref_fn *fn;
558 void *cb_data;
559};
560
561/*
562 * Handle one reference in a do_for_each_ref*()-style iteration,
563 * calling an each_ref_fn for each entry.
564 */
565static int do_one_ref(struct ref_entry *entry, void *cb_data)
566{
567 struct ref_entry_cb *data = cb_data;
568 struct ref_entry *old_current_ref;
569 int retval;
570
571 if (!starts_with(entry->name, data->base))
572 return 0;
573
574 if (!(data->flags & DO_FOR_EACH_INCLUDE_BROKEN) &&
575 !ref_resolves_to_object(entry))
576 return 0;
577
578 /* Store the old value, in case this is a recursive call: */
579 old_current_ref = current_ref;
580 current_ref = entry;
581 retval = data->fn(entry->name + data->trim, &entry->u.value.oid,
582 entry->flag, data->cb_data);
583 current_ref = old_current_ref;
584 return retval;
585}
586
587/*
588 * Call fn for each reference in dir that has index in the range
589 * offset <= index < dir->nr. Recurse into subdirectories that are in
590 * that index range, sorting them before iterating. This function
591 * does not sort dir itself; it should be sorted beforehand. fn is
592 * called for all references, including broken ones.
593 */
594static int do_for_each_entry_in_dir(struct ref_dir *dir, int offset,
595 each_ref_entry_fn fn, void *cb_data)
596{
597 int i;
598 assert(dir->sorted == dir->nr);
599 for (i = offset; i < dir->nr; i++) {
600 struct ref_entry *entry = dir->entries[i];
601 int retval;
602 if (entry->flag & REF_DIR) {
603 struct ref_dir *subdir = get_ref_dir(entry);
604 sort_ref_dir(subdir);
605 retval = do_for_each_entry_in_dir(subdir, 0, fn, cb_data);
606 } else {
607 retval = fn(entry, cb_data);
608 }
609 if (retval)
610 return retval;
611 }
612 return 0;
613}
614
615/*
616 * Call fn for each reference in the union of dir1 and dir2, in order
617 * by refname. Recurse into subdirectories. If a value entry appears
618 * in both dir1 and dir2, then only process the version that is in
619 * dir2. The input dirs must already be sorted, but subdirs will be
620 * sorted as needed. fn is called for all references, including
621 * broken ones.
622 */
623static int do_for_each_entry_in_dirs(struct ref_dir *dir1,
624 struct ref_dir *dir2,
625 each_ref_entry_fn fn, void *cb_data)
626{
627 int retval;
628 int i1 = 0, i2 = 0;
629
630 assert(dir1->sorted == dir1->nr);
631 assert(dir2->sorted == dir2->nr);
632 while (1) {
633 struct ref_entry *e1, *e2;
634 int cmp;
635 if (i1 == dir1->nr) {
636 return do_for_each_entry_in_dir(dir2, i2, fn, cb_data);
637 }
638 if (i2 == dir2->nr) {
639 return do_for_each_entry_in_dir(dir1, i1, fn, cb_data);
640 }
641 e1 = dir1->entries[i1];
642 e2 = dir2->entries[i2];
643 cmp = strcmp(e1->name, e2->name);
644 if (cmp == 0) {
645 if ((e1->flag & REF_DIR) && (e2->flag & REF_DIR)) {
646 /* Both are directories; descend them in parallel. */
647 struct ref_dir *subdir1 = get_ref_dir(e1);
648 struct ref_dir *subdir2 = get_ref_dir(e2);
649 sort_ref_dir(subdir1);
650 sort_ref_dir(subdir2);
651 retval = do_for_each_entry_in_dirs(
652 subdir1, subdir2, fn, cb_data);
653 i1++;
654 i2++;
655 } else if (!(e1->flag & REF_DIR) && !(e2->flag & REF_DIR)) {
656 /* Both are references; ignore the one from dir1. */
657 retval = fn(e2, cb_data);
658 i1++;
659 i2++;
660 } else {
661 die("conflict between reference and directory: %s",
662 e1->name);
663 }
664 } else {
665 struct ref_entry *e;
666 if (cmp < 0) {
667 e = e1;
668 i1++;
669 } else {
670 e = e2;
671 i2++;
672 }
673 if (e->flag & REF_DIR) {
674 struct ref_dir *subdir = get_ref_dir(e);
675 sort_ref_dir(subdir);
676 retval = do_for_each_entry_in_dir(
677 subdir, 0, fn, cb_data);
678 } else {
679 retval = fn(e, cb_data);
680 }
681 }
682 if (retval)
683 return retval;
684 }
685}
686
687/*
688 * Load all of the refs from the dir into our in-memory cache. The hard work
689 * of loading loose refs is done by get_ref_dir(), so we just need to recurse
690 * through all of the sub-directories. We do not even need to care about
691 * sorting, as traversal order does not matter to us.
692 */
693static void prime_ref_dir(struct ref_dir *dir)
694{
695 int i;
696 for (i = 0; i < dir->nr; i++) {
697 struct ref_entry *entry = dir->entries[i];
698 if (entry->flag & REF_DIR)
699 prime_ref_dir(get_ref_dir(entry));
700 }
701}
702
703struct nonmatching_ref_data {
704 const struct string_list *skip;
705 const char *conflicting_refname;
706};
707
708static int nonmatching_ref_fn(struct ref_entry *entry, void *vdata)
709{
710 struct nonmatching_ref_data *data = vdata;
711
712 if (data->skip && string_list_has_string(data->skip, entry->name))
713 return 0;
714
715 data->conflicting_refname = entry->name;
716 return 1;
717}
718
719/*
720 * Return 0 if a reference named refname could be created without
721 * conflicting with the name of an existing reference in dir.
722 * See verify_refname_available for more information.
723 */
724static int verify_refname_available_dir(const char *refname,
725 const struct string_list *extras,
726 const struct string_list *skip,
727 struct ref_dir *dir,
728 struct strbuf *err)
729{
730 const char *slash;
0845122c 731 const char *extra_refname;
7bd9bcf3
MH
732 int pos;
733 struct strbuf dirname = STRBUF_INIT;
734 int ret = -1;
735
736 /*
737 * For the sake of comments in this function, suppose that
738 * refname is "refs/foo/bar".
739 */
740
741 assert(err);
742
743 strbuf_grow(&dirname, strlen(refname) + 1);
744 for (slash = strchr(refname, '/'); slash; slash = strchr(slash + 1, '/')) {
745 /* Expand dirname to the new prefix, not including the trailing slash: */
746 strbuf_add(&dirname, refname + dirname.len, slash - refname - dirname.len);
747
748 /*
749 * We are still at a leading dir of the refname (e.g.,
750 * "refs/foo"; if there is a reference with that name,
751 * it is a conflict, *unless* it is in skip.
752 */
753 if (dir) {
754 pos = search_ref_dir(dir, dirname.buf, dirname.len);
755 if (pos >= 0 &&
756 (!skip || !string_list_has_string(skip, dirname.buf))) {
757 /*
758 * We found a reference whose name is
759 * a proper prefix of refname; e.g.,
760 * "refs/foo", and is not in skip.
761 */
762 strbuf_addf(err, "'%s' exists; cannot create '%s'",
763 dirname.buf, refname);
764 goto cleanup;
765 }
766 }
767
768 if (extras && string_list_has_string(extras, dirname.buf) &&
769 (!skip || !string_list_has_string(skip, dirname.buf))) {
770 strbuf_addf(err, "cannot process '%s' and '%s' at the same time",
771 refname, dirname.buf);
772 goto cleanup;
773 }
774
775 /*
776 * Otherwise, we can try to continue our search with
777 * the next component. So try to look up the
778 * directory, e.g., "refs/foo/". If we come up empty,
779 * we know there is nothing under this whole prefix,
780 * but even in that case we still have to continue the
781 * search for conflicts with extras.
782 */
783 strbuf_addch(&dirname, '/');
784 if (dir) {
785 pos = search_ref_dir(dir, dirname.buf, dirname.len);
786 if (pos < 0) {
787 /*
788 * There was no directory "refs/foo/",
789 * so there is nothing under this
790 * whole prefix. So there is no need
791 * to continue looking for conflicting
792 * references. But we need to continue
793 * looking for conflicting extras.
794 */
795 dir = NULL;
796 } else {
797 dir = get_ref_dir(dir->entries[pos]);
798 }
799 }
800 }
801
802 /*
803 * We are at the leaf of our refname (e.g., "refs/foo/bar").
804 * There is no point in searching for a reference with that
805 * name, because a refname isn't considered to conflict with
806 * itself. But we still need to check for references whose
807 * names are in the "refs/foo/bar/" namespace, because they
808 * *do* conflict.
809 */
810 strbuf_addstr(&dirname, refname + dirname.len);
811 strbuf_addch(&dirname, '/');
812
813 if (dir) {
814 pos = search_ref_dir(dir, dirname.buf, dirname.len);
815
816 if (pos >= 0) {
817 /*
818 * We found a directory named "$refname/"
819 * (e.g., "refs/foo/bar/"). It is a problem
820 * iff it contains any ref that is not in
821 * "skip".
822 */
823 struct nonmatching_ref_data data;
824
825 data.skip = skip;
826 data.conflicting_refname = NULL;
827 dir = get_ref_dir(dir->entries[pos]);
828 sort_ref_dir(dir);
829 if (do_for_each_entry_in_dir(dir, 0, nonmatching_ref_fn, &data)) {
830 strbuf_addf(err, "'%s' exists; cannot create '%s'",
831 data.conflicting_refname, refname);
832 goto cleanup;
833 }
834 }
835 }
836
0845122c
DT
837 extra_refname = find_descendant_ref(dirname.buf, extras, skip);
838 if (extra_refname)
839 strbuf_addf(err, "cannot process '%s' and '%s' at the same time",
840 refname, extra_refname);
841 else
842 ret = 0;
7bd9bcf3
MH
843
844cleanup:
845 strbuf_release(&dirname);
846 return ret;
847}
848
849struct packed_ref_cache {
850 struct ref_entry *root;
851
852 /*
853 * Count of references to the data structure in this instance,
854 * including the pointer from ref_cache::packed if any. The
855 * data will not be freed as long as the reference count is
856 * nonzero.
857 */
858 unsigned int referrers;
859
860 /*
861 * Iff the packed-refs file associated with this instance is
862 * currently locked for writing, this points at the associated
863 * lock (which is owned by somebody else). The referrer count
864 * is also incremented when the file is locked and decremented
865 * when it is unlocked.
866 */
867 struct lock_file *lock;
868
869 /* The metadata from when this packed-refs cache was read */
870 struct stat_validity validity;
871};
872
873/*
874 * Future: need to be in "struct repository"
875 * when doing a full libification.
876 */
877static struct ref_cache {
878 struct ref_cache *next;
879 struct ref_entry *loose;
880 struct packed_ref_cache *packed;
881 /*
882 * The submodule name, or "" for the main repo. We allocate
883 * length 1 rather than FLEX_ARRAY so that the main ref_cache
884 * is initialized correctly.
885 */
886 char name[1];
887} ref_cache, *submodule_ref_caches;
888
889/* Lock used for the main packed-refs file: */
890static struct lock_file packlock;
891
892/*
893 * Increment the reference count of *packed_refs.
894 */
895static void acquire_packed_ref_cache(struct packed_ref_cache *packed_refs)
896{
897 packed_refs->referrers++;
898}
899
900/*
901 * Decrease the reference count of *packed_refs. If it goes to zero,
902 * free *packed_refs and return true; otherwise return false.
903 */
904static int release_packed_ref_cache(struct packed_ref_cache *packed_refs)
905{
906 if (!--packed_refs->referrers) {
907 free_ref_entry(packed_refs->root);
908 stat_validity_clear(&packed_refs->validity);
909 free(packed_refs);
910 return 1;
911 } else {
912 return 0;
913 }
914}
915
916static void clear_packed_ref_cache(struct ref_cache *refs)
917{
918 if (refs->packed) {
919 struct packed_ref_cache *packed_refs = refs->packed;
920
921 if (packed_refs->lock)
922 die("internal error: packed-ref cache cleared while locked");
923 refs->packed = NULL;
924 release_packed_ref_cache(packed_refs);
925 }
926}
927
928static void clear_loose_ref_cache(struct ref_cache *refs)
929{
930 if (refs->loose) {
931 free_ref_entry(refs->loose);
932 refs->loose = NULL;
933 }
934}
935
a2d5156c
JK
936/*
937 * Create a new submodule ref cache and add it to the internal
938 * set of caches.
939 */
7bd9bcf3
MH
940static struct ref_cache *create_ref_cache(const char *submodule)
941{
942 int len;
943 struct ref_cache *refs;
944 if (!submodule)
945 submodule = "";
946 len = strlen(submodule) + 1;
947 refs = xcalloc(1, sizeof(struct ref_cache) + len);
948 memcpy(refs->name, submodule, len);
a2d5156c
JK
949 refs->next = submodule_ref_caches;
950 submodule_ref_caches = refs;
7bd9bcf3
MH
951 return refs;
952}
953
a2d5156c 954static struct ref_cache *lookup_ref_cache(const char *submodule)
7bd9bcf3
MH
955{
956 struct ref_cache *refs;
957
958 if (!submodule || !*submodule)
959 return &ref_cache;
960
961 for (refs = submodule_ref_caches; refs; refs = refs->next)
962 if (!strcmp(submodule, refs->name))
963 return refs;
a2d5156c
JK
964 return NULL;
965}
7bd9bcf3 966
a2d5156c
JK
967/*
968 * Return a pointer to a ref_cache for the specified submodule. For
969 * the main repository, use submodule==NULL. The returned structure
970 * will be allocated and initialized but not necessarily populated; it
971 * should not be freed.
972 */
973static struct ref_cache *get_ref_cache(const char *submodule)
974{
975 struct ref_cache *refs = lookup_ref_cache(submodule);
976 if (!refs)
977 refs = create_ref_cache(submodule);
7bd9bcf3
MH
978 return refs;
979}
980
981/* The length of a peeled reference line in packed-refs, including EOL: */
982#define PEELED_LINE_LENGTH 42
983
984/*
985 * The packed-refs header line that we write out. Perhaps other
986 * traits will be added later. The trailing space is required.
987 */
988static const char PACKED_REFS_HEADER[] =
989 "# pack-refs with: peeled fully-peeled \n";
990
991/*
992 * Parse one line from a packed-refs file. Write the SHA1 to sha1.
993 * Return a pointer to the refname within the line (null-terminated),
994 * or NULL if there was a problem.
995 */
996static const char *parse_ref_line(struct strbuf *line, unsigned char *sha1)
997{
998 const char *ref;
999
1000 /*
1001 * 42: the answer to everything.
1002 *
1003 * In this case, it happens to be the answer to
1004 * 40 (length of sha1 hex representation)
1005 * +1 (space in between hex and name)
1006 * +1 (newline at the end of the line)
1007 */
1008 if (line->len <= 42)
1009 return NULL;
1010
1011 if (get_sha1_hex(line->buf, sha1) < 0)
1012 return NULL;
1013 if (!isspace(line->buf[40]))
1014 return NULL;
1015
1016 ref = line->buf + 41;
1017 if (isspace(*ref))
1018 return NULL;
1019
1020 if (line->buf[line->len - 1] != '\n')
1021 return NULL;
1022 line->buf[--line->len] = 0;
1023
1024 return ref;
1025}
1026
1027/*
1028 * Read f, which is a packed-refs file, into dir.
1029 *
1030 * A comment line of the form "# pack-refs with: " may contain zero or
1031 * more traits. We interpret the traits as follows:
1032 *
1033 * No traits:
1034 *
1035 * Probably no references are peeled. But if the file contains a
1036 * peeled value for a reference, we will use it.
1037 *
1038 * peeled:
1039 *
1040 * References under "refs/tags/", if they *can* be peeled, *are*
1041 * peeled in this file. References outside of "refs/tags/" are
1042 * probably not peeled even if they could have been, but if we find
1043 * a peeled value for such a reference we will use it.
1044 *
1045 * fully-peeled:
1046 *
1047 * All references in the file that can be peeled are peeled.
1048 * Inversely (and this is more important), any references in the
1049 * file for which no peeled value is recorded is not peelable. This
1050 * trait should typically be written alongside "peeled" for
1051 * compatibility with older clients, but we do not require it
1052 * (i.e., "peeled" is a no-op if "fully-peeled" is set).
1053 */
1054static void read_packed_refs(FILE *f, struct ref_dir *dir)
1055{
1056 struct ref_entry *last = NULL;
1057 struct strbuf line = STRBUF_INIT;
1058 enum { PEELED_NONE, PEELED_TAGS, PEELED_FULLY } peeled = PEELED_NONE;
1059
1060 while (strbuf_getwholeline(&line, f, '\n') != EOF) {
1061 unsigned char sha1[20];
1062 const char *refname;
1063 const char *traits;
1064
1065 if (skip_prefix(line.buf, "# pack-refs with:", &traits)) {
1066 if (strstr(traits, " fully-peeled "))
1067 peeled = PEELED_FULLY;
1068 else if (strstr(traits, " peeled "))
1069 peeled = PEELED_TAGS;
1070 /* perhaps other traits later as well */
1071 continue;
1072 }
1073
1074 refname = parse_ref_line(&line, sha1);
1075 if (refname) {
1076 int flag = REF_ISPACKED;
1077
1078 if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
1079 if (!refname_is_safe(refname))
1080 die("packed refname is dangerous: %s", refname);
1081 hashclr(sha1);
1082 flag |= REF_BAD_NAME | REF_ISBROKEN;
1083 }
1084 last = create_ref_entry(refname, sha1, flag, 0);
1085 if (peeled == PEELED_FULLY ||
1086 (peeled == PEELED_TAGS && starts_with(refname, "refs/tags/")))
1087 last->flag |= REF_KNOWS_PEELED;
1088 add_ref(dir, last);
1089 continue;
1090 }
1091 if (last &&
1092 line.buf[0] == '^' &&
1093 line.len == PEELED_LINE_LENGTH &&
1094 line.buf[PEELED_LINE_LENGTH - 1] == '\n' &&
1095 !get_sha1_hex(line.buf + 1, sha1)) {
1096 hashcpy(last->u.value.peeled.hash, sha1);
1097 /*
1098 * Regardless of what the file header said,
1099 * we definitely know the value of *this*
1100 * reference:
1101 */
1102 last->flag |= REF_KNOWS_PEELED;
1103 }
1104 }
1105
1106 strbuf_release(&line);
1107}
1108
1109/*
1110 * Get the packed_ref_cache for the specified ref_cache, creating it
1111 * if necessary.
1112 */
1113static struct packed_ref_cache *get_packed_ref_cache(struct ref_cache *refs)
1114{
1115 char *packed_refs_file;
1116
1117 if (*refs->name)
1118 packed_refs_file = git_pathdup_submodule(refs->name, "packed-refs");
1119 else
1120 packed_refs_file = git_pathdup("packed-refs");
1121
1122 if (refs->packed &&
1123 !stat_validity_check(&refs->packed->validity, packed_refs_file))
1124 clear_packed_ref_cache(refs);
1125
1126 if (!refs->packed) {
1127 FILE *f;
1128
1129 refs->packed = xcalloc(1, sizeof(*refs->packed));
1130 acquire_packed_ref_cache(refs->packed);
1131 refs->packed->root = create_dir_entry(refs, "", 0, 0);
1132 f = fopen(packed_refs_file, "r");
1133 if (f) {
1134 stat_validity_update(&refs->packed->validity, fileno(f));
1135 read_packed_refs(f, get_ref_dir(refs->packed->root));
1136 fclose(f);
1137 }
1138 }
1139 free(packed_refs_file);
1140 return refs->packed;
1141}
1142
1143static struct ref_dir *get_packed_ref_dir(struct packed_ref_cache *packed_ref_cache)
1144{
1145 return get_ref_dir(packed_ref_cache->root);
1146}
1147
1148static struct ref_dir *get_packed_refs(struct ref_cache *refs)
1149{
1150 return get_packed_ref_dir(get_packed_ref_cache(refs));
1151}
1152
1153/*
1154 * Add a reference to the in-memory packed reference cache. This may
1155 * only be called while the packed-refs file is locked (see
1156 * lock_packed_refs()). To actually write the packed-refs file, call
1157 * commit_packed_refs().
1158 */
1159static void add_packed_ref(const char *refname, const unsigned char *sha1)
1160{
1161 struct packed_ref_cache *packed_ref_cache =
1162 get_packed_ref_cache(&ref_cache);
1163
1164 if (!packed_ref_cache->lock)
1165 die("internal error: packed refs not locked");
1166 add_ref(get_packed_ref_dir(packed_ref_cache),
1167 create_ref_entry(refname, sha1, REF_ISPACKED, 1));
1168}
1169
1170/*
1171 * Read the loose references from the namespace dirname into dir
1172 * (without recursing). dirname must end with '/'. dir must be the
1173 * directory entry corresponding to dirname.
1174 */
1175static void read_loose_refs(const char *dirname, struct ref_dir *dir)
1176{
1177 struct ref_cache *refs = dir->ref_cache;
1178 DIR *d;
1179 struct dirent *de;
1180 int dirnamelen = strlen(dirname);
1181 struct strbuf refname;
1182 struct strbuf path = STRBUF_INIT;
1183 size_t path_baselen;
1184
1185 if (*refs->name)
1186 strbuf_git_path_submodule(&path, refs->name, "%s", dirname);
1187 else
1188 strbuf_git_path(&path, "%s", dirname);
1189 path_baselen = path.len;
1190
1191 d = opendir(path.buf);
1192 if (!d) {
1193 strbuf_release(&path);
1194 return;
1195 }
1196
1197 strbuf_init(&refname, dirnamelen + 257);
1198 strbuf_add(&refname, dirname, dirnamelen);
1199
1200 while ((de = readdir(d)) != NULL) {
1201 unsigned char sha1[20];
1202 struct stat st;
1203 int flag;
1204
1205 if (de->d_name[0] == '.')
1206 continue;
1207 if (ends_with(de->d_name, ".lock"))
1208 continue;
1209 strbuf_addstr(&refname, de->d_name);
1210 strbuf_addstr(&path, de->d_name);
1211 if (stat(path.buf, &st) < 0) {
1212 ; /* silently ignore */
1213 } else if (S_ISDIR(st.st_mode)) {
1214 strbuf_addch(&refname, '/');
1215 add_entry_to_dir(dir,
1216 create_dir_entry(refs, refname.buf,
1217 refname.len, 1));
1218 } else {
1219 int read_ok;
1220
1221 if (*refs->name) {
1222 hashclr(sha1);
1223 flag = 0;
1224 read_ok = !resolve_gitlink_ref(refs->name,
1225 refname.buf, sha1);
1226 } else {
1227 read_ok = !read_ref_full(refname.buf,
1228 RESOLVE_REF_READING,
1229 sha1, &flag);
1230 }
1231
1232 if (!read_ok) {
1233 hashclr(sha1);
1234 flag |= REF_ISBROKEN;
1235 } else if (is_null_sha1(sha1)) {
1236 /*
1237 * It is so astronomically unlikely
1238 * that NULL_SHA1 is the SHA-1 of an
1239 * actual object that we consider its
1240 * appearance in a loose reference
1241 * file to be repo corruption
1242 * (probably due to a software bug).
1243 */
1244 flag |= REF_ISBROKEN;
1245 }
1246
1247 if (check_refname_format(refname.buf,
1248 REFNAME_ALLOW_ONELEVEL)) {
1249 if (!refname_is_safe(refname.buf))
1250 die("loose refname is dangerous: %s", refname.buf);
1251 hashclr(sha1);
1252 flag |= REF_BAD_NAME | REF_ISBROKEN;
1253 }
1254 add_entry_to_dir(dir,
1255 create_ref_entry(refname.buf, sha1, flag, 0));
1256 }
1257 strbuf_setlen(&refname, dirnamelen);
1258 strbuf_setlen(&path, path_baselen);
1259 }
1260 strbuf_release(&refname);
1261 strbuf_release(&path);
1262 closedir(d);
1263}
1264
1265static struct ref_dir *get_loose_refs(struct ref_cache *refs)
1266{
1267 if (!refs->loose) {
1268 /*
1269 * Mark the top-level directory complete because we
1270 * are about to read the only subdirectory that can
1271 * hold references:
1272 */
1273 refs->loose = create_dir_entry(refs, "", 0, 0);
1274 /*
1275 * Create an incomplete entry for "refs/":
1276 */
1277 add_entry_to_dir(get_ref_dir(refs->loose),
1278 create_dir_entry(refs, "refs/", 5, 1));
1279 }
1280 return get_ref_dir(refs->loose);
1281}
1282
1283/* We allow "recursive" symbolic refs. Only within reason, though */
1284#define MAXDEPTH 5
1285#define MAXREFLEN (1024)
1286
1287/*
1288 * Called by resolve_gitlink_ref_recursive() after it failed to read
1289 * from the loose refs in ref_cache refs. Find <refname> in the
1290 * packed-refs file for the submodule.
1291 */
1292static int resolve_gitlink_packed_ref(struct ref_cache *refs,
1293 const char *refname, unsigned char *sha1)
1294{
1295 struct ref_entry *ref;
1296 struct ref_dir *dir = get_packed_refs(refs);
1297
1298 ref = find_ref(dir, refname);
1299 if (ref == NULL)
1300 return -1;
1301
1302 hashcpy(sha1, ref->u.value.oid.hash);
1303 return 0;
1304}
1305
1306static int resolve_gitlink_ref_recursive(struct ref_cache *refs,
1307 const char *refname, unsigned char *sha1,
1308 int recursion)
1309{
1310 int fd, len;
1311 char buffer[128], *p;
1312 char *path;
1313
1314 if (recursion > MAXDEPTH || strlen(refname) > MAXREFLEN)
1315 return -1;
1316 path = *refs->name
1317 ? git_pathdup_submodule(refs->name, "%s", refname)
1318 : git_pathdup("%s", refname);
1319 fd = open(path, O_RDONLY);
1320 free(path);
1321 if (fd < 0)
1322 return resolve_gitlink_packed_ref(refs, refname, sha1);
1323
1324 len = read(fd, buffer, sizeof(buffer)-1);
1325 close(fd);
1326 if (len < 0)
1327 return -1;
1328 while (len && isspace(buffer[len-1]))
1329 len--;
1330 buffer[len] = 0;
1331
1332 /* Was it a detached head or an old-fashioned symlink? */
1333 if (!get_sha1_hex(buffer, sha1))
1334 return 0;
1335
1336 /* Symref? */
1337 if (strncmp(buffer, "ref:", 4))
1338 return -1;
1339 p = buffer + 4;
1340 while (isspace(*p))
1341 p++;
1342
1343 return resolve_gitlink_ref_recursive(refs, p, sha1, recursion+1);
1344}
1345
1346int resolve_gitlink_ref(const char *path, const char *refname, unsigned char *sha1)
1347{
1348 int len = strlen(path), retval;
a2d5156c 1349 struct strbuf submodule = STRBUF_INIT;
7bd9bcf3
MH
1350 struct ref_cache *refs;
1351
1352 while (len && path[len-1] == '/')
1353 len--;
1354 if (!len)
1355 return -1;
a2d5156c
JK
1356
1357 strbuf_add(&submodule, path, len);
1358 refs = lookup_ref_cache(submodule.buf);
1359 if (!refs) {
1360 if (!is_nonbare_repository_dir(&submodule)) {
1361 strbuf_release(&submodule);
1362 return -1;
1363 }
1364 refs = create_ref_cache(submodule.buf);
1365 }
1366 strbuf_release(&submodule);
7bd9bcf3
MH
1367
1368 retval = resolve_gitlink_ref_recursive(refs, refname, sha1, 0);
1369 return retval;
1370}
1371
1372/*
1373 * Return the ref_entry for the given refname from the packed
1374 * references. If it does not exist, return NULL.
1375 */
1376static struct ref_entry *get_packed_ref(const char *refname)
1377{
1378 return find_ref(get_packed_refs(&ref_cache), refname);
1379}
1380
1381/*
1382 * A loose ref file doesn't exist; check for a packed ref. The
1383 * options are forwarded from resolve_safe_unsafe().
1384 */
1385static int resolve_missing_loose_ref(const char *refname,
1386 int resolve_flags,
1387 unsigned char *sha1,
1388 int *flags)
1389{
1390 struct ref_entry *entry;
1391
1392 /*
1393 * The loose reference file does not exist; check for a packed
1394 * reference.
1395 */
1396 entry = get_packed_ref(refname);
1397 if (entry) {
1398 hashcpy(sha1, entry->u.value.oid.hash);
1399 if (flags)
1400 *flags |= REF_ISPACKED;
1401 return 0;
1402 }
1403 /* The reference is not a packed reference, either. */
1404 if (resolve_flags & RESOLVE_REF_READING) {
1405 errno = ENOENT;
1406 return -1;
1407 } else {
1408 hashclr(sha1);
1409 return 0;
1410 }
1411}
1412
1413/* This function needs to return a meaningful errno on failure */
1414static const char *resolve_ref_1(const char *refname,
1415 int resolve_flags,
1416 unsigned char *sha1,
1417 int *flags,
1418 struct strbuf *sb_refname,
1419 struct strbuf *sb_path,
1420 struct strbuf *sb_contents)
1421{
1422 int depth = MAXDEPTH;
1423 int bad_name = 0;
1424
1425 if (flags)
1426 *flags = 0;
1427
1428 if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
1429 if (flags)
1430 *flags |= REF_BAD_NAME;
1431
1432 if (!(resolve_flags & RESOLVE_REF_ALLOW_BAD_NAME) ||
1433 !refname_is_safe(refname)) {
1434 errno = EINVAL;
1435 return NULL;
1436 }
1437 /*
1438 * dwim_ref() uses REF_ISBROKEN to distinguish between
1439 * missing refs and refs that were present but invalid,
1440 * to complain about the latter to stderr.
1441 *
1442 * We don't know whether the ref exists, so don't set
1443 * REF_ISBROKEN yet.
1444 */
1445 bad_name = 1;
1446 }
1447 for (;;) {
1448 const char *path;
1449 struct stat st;
1450 char *buf;
1451 int fd;
1452
1453 if (--depth < 0) {
1454 errno = ELOOP;
1455 return NULL;
1456 }
1457
1458 strbuf_reset(sb_path);
1459 strbuf_git_path(sb_path, "%s", refname);
1460 path = sb_path->buf;
1461
1462 /*
1463 * We might have to loop back here to avoid a race
1464 * condition: first we lstat() the file, then we try
1465 * to read it as a link or as a file. But if somebody
1466 * changes the type of the file (file <-> directory
1467 * <-> symlink) between the lstat() and reading, then
1468 * we don't want to report that as an error but rather
1469 * try again starting with the lstat().
1470 */
1471 stat_ref:
1472 if (lstat(path, &st) < 0) {
1473 if (errno != ENOENT)
1474 return NULL;
1475 if (resolve_missing_loose_ref(refname, resolve_flags,
1476 sha1, flags))
1477 return NULL;
1478 if (bad_name) {
1479 hashclr(sha1);
1480 if (flags)
1481 *flags |= REF_ISBROKEN;
1482 }
1483 return refname;
1484 }
1485
1486 /* Follow "normalized" - ie "refs/.." symlinks by hand */
1487 if (S_ISLNK(st.st_mode)) {
1488 strbuf_reset(sb_contents);
1489 if (strbuf_readlink(sb_contents, path, 0) < 0) {
1490 if (errno == ENOENT || errno == EINVAL)
1491 /* inconsistent with lstat; retry */
1492 goto stat_ref;
1493 else
1494 return NULL;
1495 }
1496 if (starts_with(sb_contents->buf, "refs/") &&
1497 !check_refname_format(sb_contents->buf, 0)) {
1498 strbuf_swap(sb_refname, sb_contents);
1499 refname = sb_refname->buf;
1500 if (flags)
1501 *flags |= REF_ISSYMREF;
1502 if (resolve_flags & RESOLVE_REF_NO_RECURSE) {
1503 hashclr(sha1);
1504 return refname;
1505 }
1506 continue;
1507 }
1508 }
1509
1510 /* Is it a directory? */
1511 if (S_ISDIR(st.st_mode)) {
1512 errno = EISDIR;
1513 return NULL;
1514 }
1515
1516 /*
1517 * Anything else, just open it and try to use it as
1518 * a ref
1519 */
1520 fd = open(path, O_RDONLY);
1521 if (fd < 0) {
1522 if (errno == ENOENT)
1523 /* inconsistent with lstat; retry */
1524 goto stat_ref;
1525 else
1526 return NULL;
1527 }
1528 strbuf_reset(sb_contents);
1529 if (strbuf_read(sb_contents, fd, 256) < 0) {
1530 int save_errno = errno;
1531 close(fd);
1532 errno = save_errno;
1533 return NULL;
1534 }
1535 close(fd);
1536 strbuf_rtrim(sb_contents);
1537
1538 /*
1539 * Is it a symbolic ref?
1540 */
1541 if (!starts_with(sb_contents->buf, "ref:")) {
1542 /*
1543 * Please note that FETCH_HEAD has a second
1544 * line containing other data.
1545 */
1546 if (get_sha1_hex(sb_contents->buf, sha1) ||
1547 (sb_contents->buf[40] != '\0' && !isspace(sb_contents->buf[40]))) {
1548 if (flags)
1549 *flags |= REF_ISBROKEN;
1550 errno = EINVAL;
1551 return NULL;
1552 }
1553 if (bad_name) {
1554 hashclr(sha1);
1555 if (flags)
1556 *flags |= REF_ISBROKEN;
1557 }
1558 return refname;
1559 }
1560 if (flags)
1561 *flags |= REF_ISSYMREF;
1562 buf = sb_contents->buf + 4;
1563 while (isspace(*buf))
1564 buf++;
1565 strbuf_reset(sb_refname);
1566 strbuf_addstr(sb_refname, buf);
1567 refname = sb_refname->buf;
1568 if (resolve_flags & RESOLVE_REF_NO_RECURSE) {
1569 hashclr(sha1);
1570 return refname;
1571 }
1572 if (check_refname_format(buf, REFNAME_ALLOW_ONELEVEL)) {
1573 if (flags)
1574 *flags |= REF_ISBROKEN;
1575
1576 if (!(resolve_flags & RESOLVE_REF_ALLOW_BAD_NAME) ||
1577 !refname_is_safe(buf)) {
1578 errno = EINVAL;
1579 return NULL;
1580 }
1581 bad_name = 1;
1582 }
1583 }
1584}
1585
1586const char *resolve_ref_unsafe(const char *refname, int resolve_flags,
1587 unsigned char *sha1, int *flags)
1588{
1589 static struct strbuf sb_refname = STRBUF_INIT;
1590 struct strbuf sb_contents = STRBUF_INIT;
1591 struct strbuf sb_path = STRBUF_INIT;
1592 const char *ret;
1593
1594 ret = resolve_ref_1(refname, resolve_flags, sha1, flags,
1595 &sb_refname, &sb_path, &sb_contents);
1596 strbuf_release(&sb_path);
1597 strbuf_release(&sb_contents);
1598 return ret;
1599}
1600
1601/*
1602 * Peel the entry (if possible) and return its new peel_status. If
1603 * repeel is true, re-peel the entry even if there is an old peeled
1604 * value that is already stored in it.
1605 *
1606 * It is OK to call this function with a packed reference entry that
1607 * might be stale and might even refer to an object that has since
1608 * been garbage-collected. In such a case, if the entry has
1609 * REF_KNOWS_PEELED then leave the status unchanged and return
1610 * PEEL_PEELED or PEEL_NON_TAG; otherwise, return PEEL_INVALID.
1611 */
1612static enum peel_status peel_entry(struct ref_entry *entry, int repeel)
1613{
1614 enum peel_status status;
1615
1616 if (entry->flag & REF_KNOWS_PEELED) {
1617 if (repeel) {
1618 entry->flag &= ~REF_KNOWS_PEELED;
1619 oidclr(&entry->u.value.peeled);
1620 } else {
1621 return is_null_oid(&entry->u.value.peeled) ?
1622 PEEL_NON_TAG : PEEL_PEELED;
1623 }
1624 }
1625 if (entry->flag & REF_ISBROKEN)
1626 return PEEL_BROKEN;
1627 if (entry->flag & REF_ISSYMREF)
1628 return PEEL_IS_SYMREF;
1629
1630 status = peel_object(entry->u.value.oid.hash, entry->u.value.peeled.hash);
1631 if (status == PEEL_PEELED || status == PEEL_NON_TAG)
1632 entry->flag |= REF_KNOWS_PEELED;
1633 return status;
1634}
1635
1636int peel_ref(const char *refname, unsigned char *sha1)
1637{
1638 int flag;
1639 unsigned char base[20];
1640
1641 if (current_ref && (current_ref->name == refname
1642 || !strcmp(current_ref->name, refname))) {
1643 if (peel_entry(current_ref, 0))
1644 return -1;
1645 hashcpy(sha1, current_ref->u.value.peeled.hash);
1646 return 0;
1647 }
1648
1649 if (read_ref_full(refname, RESOLVE_REF_READING, base, &flag))
1650 return -1;
1651
1652 /*
1653 * If the reference is packed, read its ref_entry from the
1654 * cache in the hope that we already know its peeled value.
1655 * We only try this optimization on packed references because
1656 * (a) forcing the filling of the loose reference cache could
1657 * be expensive and (b) loose references anyway usually do not
1658 * have REF_KNOWS_PEELED.
1659 */
1660 if (flag & REF_ISPACKED) {
1661 struct ref_entry *r = get_packed_ref(refname);
1662 if (r) {
1663 if (peel_entry(r, 0))
1664 return -1;
1665 hashcpy(sha1, r->u.value.peeled.hash);
1666 return 0;
1667 }
1668 }
1669
1670 return peel_object(base, sha1);
1671}
1672
1673/*
1674 * Call fn for each reference in the specified ref_cache, omitting
1675 * references not in the containing_dir of base. fn is called for all
1676 * references, including broken ones. If fn ever returns a non-zero
1677 * value, stop the iteration and return that value; otherwise, return
1678 * 0.
1679 */
1680static int do_for_each_entry(struct ref_cache *refs, const char *base,
1681 each_ref_entry_fn fn, void *cb_data)
1682{
1683 struct packed_ref_cache *packed_ref_cache;
1684 struct ref_dir *loose_dir;
1685 struct ref_dir *packed_dir;
1686 int retval = 0;
1687
1688 /*
1689 * We must make sure that all loose refs are read before accessing the
1690 * packed-refs file; this avoids a race condition in which loose refs
1691 * are migrated to the packed-refs file by a simultaneous process, but
1692 * our in-memory view is from before the migration. get_packed_ref_cache()
1693 * takes care of making sure our view is up to date with what is on
1694 * disk.
1695 */
1696 loose_dir = get_loose_refs(refs);
1697 if (base && *base) {
1698 loose_dir = find_containing_dir(loose_dir, base, 0);
1699 }
1700 if (loose_dir)
1701 prime_ref_dir(loose_dir);
1702
1703 packed_ref_cache = get_packed_ref_cache(refs);
1704 acquire_packed_ref_cache(packed_ref_cache);
1705 packed_dir = get_packed_ref_dir(packed_ref_cache);
1706 if (base && *base) {
1707 packed_dir = find_containing_dir(packed_dir, base, 0);
1708 }
1709
1710 if (packed_dir && loose_dir) {
1711 sort_ref_dir(packed_dir);
1712 sort_ref_dir(loose_dir);
1713 retval = do_for_each_entry_in_dirs(
1714 packed_dir, loose_dir, fn, cb_data);
1715 } else if (packed_dir) {
1716 sort_ref_dir(packed_dir);
1717 retval = do_for_each_entry_in_dir(
1718 packed_dir, 0, fn, cb_data);
1719 } else if (loose_dir) {
1720 sort_ref_dir(loose_dir);
1721 retval = do_for_each_entry_in_dir(
1722 loose_dir, 0, fn, cb_data);
1723 }
1724
1725 release_packed_ref_cache(packed_ref_cache);
1726 return retval;
1727}
1728
1729/*
1730 * Call fn for each reference in the specified ref_cache for which the
1731 * refname begins with base. If trim is non-zero, then trim that many
1732 * characters off the beginning of each refname before passing the
1733 * refname to fn. flags can be DO_FOR_EACH_INCLUDE_BROKEN to include
1734 * broken references in the iteration. If fn ever returns a non-zero
1735 * value, stop the iteration and return that value; otherwise, return
1736 * 0.
1737 */
1738static int do_for_each_ref(struct ref_cache *refs, const char *base,
1739 each_ref_fn fn, int trim, int flags, void *cb_data)
1740{
1741 struct ref_entry_cb data;
1742 data.base = base;
1743 data.trim = trim;
1744 data.flags = flags;
1745 data.fn = fn;
1746 data.cb_data = cb_data;
1747
1748 if (ref_paranoia < 0)
1749 ref_paranoia = git_env_bool("GIT_REF_PARANOIA", 0);
1750 if (ref_paranoia)
1751 data.flags |= DO_FOR_EACH_INCLUDE_BROKEN;
1752
1753 return do_for_each_entry(refs, base, do_one_ref, &data);
1754}
1755
1756static int do_head_ref(const char *submodule, each_ref_fn fn, void *cb_data)
1757{
1758 struct object_id oid;
1759 int flag;
1760
1761 if (submodule) {
1762 if (resolve_gitlink_ref(submodule, "HEAD", oid.hash) == 0)
1763 return fn("HEAD", &oid, 0, cb_data);
1764
1765 return 0;
1766 }
1767
1768 if (!read_ref_full("HEAD", RESOLVE_REF_READING, oid.hash, &flag))
1769 return fn("HEAD", &oid, flag, cb_data);
1770
1771 return 0;
1772}
1773
1774int head_ref(each_ref_fn fn, void *cb_data)
1775{
1776 return do_head_ref(NULL, fn, cb_data);
1777}
1778
1779int head_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
1780{
1781 return do_head_ref(submodule, fn, cb_data);
1782}
1783
1784int for_each_ref(each_ref_fn fn, void *cb_data)
1785{
1786 return do_for_each_ref(&ref_cache, "", fn, 0, 0, cb_data);
1787}
1788
1789int for_each_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
1790{
1791 return do_for_each_ref(get_ref_cache(submodule), "", fn, 0, 0, cb_data);
1792}
1793
1794int for_each_ref_in(const char *prefix, each_ref_fn fn, void *cb_data)
1795{
1796 return do_for_each_ref(&ref_cache, prefix, fn, strlen(prefix), 0, cb_data);
1797}
1798
1799int for_each_fullref_in(const char *prefix, each_ref_fn fn, void *cb_data, unsigned int broken)
1800{
1801 unsigned int flag = 0;
1802
1803 if (broken)
1804 flag = DO_FOR_EACH_INCLUDE_BROKEN;
1805 return do_for_each_ref(&ref_cache, prefix, fn, 0, flag, cb_data);
1806}
1807
1808int for_each_ref_in_submodule(const char *submodule, const char *prefix,
1809 each_ref_fn fn, void *cb_data)
1810{
1811 return do_for_each_ref(get_ref_cache(submodule), prefix, fn, strlen(prefix), 0, cb_data);
1812}
1813
1814int for_each_replace_ref(each_ref_fn fn, void *cb_data)
1815{
1816 return do_for_each_ref(&ref_cache, git_replace_ref_base, fn,
1817 strlen(git_replace_ref_base), 0, cb_data);
1818}
1819
1820int for_each_namespaced_ref(each_ref_fn fn, void *cb_data)
1821{
1822 struct strbuf buf = STRBUF_INIT;
1823 int ret;
1824 strbuf_addf(&buf, "%srefs/", get_git_namespace());
1825 ret = do_for_each_ref(&ref_cache, buf.buf, fn, 0, 0, cb_data);
1826 strbuf_release(&buf);
1827 return ret;
1828}
1829
1830int for_each_rawref(each_ref_fn fn, void *cb_data)
1831{
1832 return do_for_each_ref(&ref_cache, "", fn, 0,
1833 DO_FOR_EACH_INCLUDE_BROKEN, cb_data);
1834}
1835
1836static void unlock_ref(struct ref_lock *lock)
1837{
1838 /* Do not free lock->lk -- atexit() still looks at them */
1839 if (lock->lk)
1840 rollback_lock_file(lock->lk);
1841 free(lock->ref_name);
1842 free(lock->orig_ref_name);
1843 free(lock);
1844}
1845
1846/*
1847 * Verify that the reference locked by lock has the value old_sha1.
1848 * Fail if the reference doesn't exist and mustexist is set. Return 0
1849 * on success. On error, write an error message to err, set errno, and
1850 * return a negative value.
1851 */
1852static int verify_lock(struct ref_lock *lock,
1853 const unsigned char *old_sha1, int mustexist,
1854 struct strbuf *err)
1855{
1856 assert(err);
1857
1858 if (read_ref_full(lock->ref_name,
1859 mustexist ? RESOLVE_REF_READING : 0,
1860 lock->old_oid.hash, NULL)) {
1861 int save_errno = errno;
1862 strbuf_addf(err, "can't verify ref %s", lock->ref_name);
1863 errno = save_errno;
1864 return -1;
1865 }
1866 if (hashcmp(lock->old_oid.hash, old_sha1)) {
1867 strbuf_addf(err, "ref %s is at %s but expected %s",
1868 lock->ref_name,
1869 sha1_to_hex(lock->old_oid.hash),
1870 sha1_to_hex(old_sha1));
1871 errno = EBUSY;
1872 return -1;
1873 }
1874 return 0;
1875}
1876
1877static int remove_empty_directories(struct strbuf *path)
1878{
1879 /*
1880 * we want to create a file but there is a directory there;
1881 * if that is an empty directory (or a directory that contains
1882 * only empty directories), remove them.
1883 */
1884 return remove_dir_recursively(path, REMOVE_DIR_EMPTY_ONLY);
1885}
1886
1887/*
1888 * Locks a ref returning the lock on success and NULL on failure.
1889 * On failure errno is set to something meaningful.
1890 */
1891static struct ref_lock *lock_ref_sha1_basic(const char *refname,
1892 const unsigned char *old_sha1,
1893 const struct string_list *extras,
1894 const struct string_list *skip,
1895 unsigned int flags, int *type_p,
1896 struct strbuf *err)
1897{
1898 struct strbuf ref_file = STRBUF_INIT;
1899 struct strbuf orig_ref_file = STRBUF_INIT;
1900 const char *orig_refname = refname;
1901 struct ref_lock *lock;
1902 int last_errno = 0;
1903 int type, lflags;
1904 int mustexist = (old_sha1 && !is_null_sha1(old_sha1));
1905 int resolve_flags = 0;
1906 int attempts_remaining = 3;
1907
1908 assert(err);
1909
1910 lock = xcalloc(1, sizeof(struct ref_lock));
1911
1912 if (mustexist)
1913 resolve_flags |= RESOLVE_REF_READING;
1914 if (flags & REF_DELETING) {
1915 resolve_flags |= RESOLVE_REF_ALLOW_BAD_NAME;
1916 if (flags & REF_NODEREF)
1917 resolve_flags |= RESOLVE_REF_NO_RECURSE;
1918 }
1919
1920 refname = resolve_ref_unsafe(refname, resolve_flags,
1921 lock->old_oid.hash, &type);
1922 if (!refname && errno == EISDIR) {
1923 /*
1924 * we are trying to lock foo but we used to
1925 * have foo/bar which now does not exist;
1926 * it is normal for the empty directory 'foo'
1927 * to remain.
1928 */
1929 strbuf_git_path(&orig_ref_file, "%s", orig_refname);
1930 if (remove_empty_directories(&orig_ref_file)) {
1931 last_errno = errno;
1932 if (!verify_refname_available_dir(orig_refname, extras, skip,
1933 get_loose_refs(&ref_cache), err))
1934 strbuf_addf(err, "there are still refs under '%s'",
1935 orig_refname);
1936 goto error_return;
1937 }
1938 refname = resolve_ref_unsafe(orig_refname, resolve_flags,
1939 lock->old_oid.hash, &type);
1940 }
1941 if (type_p)
1942 *type_p = type;
1943 if (!refname) {
1944 last_errno = errno;
1945 if (last_errno != ENOTDIR ||
1946 !verify_refname_available_dir(orig_refname, extras, skip,
1947 get_loose_refs(&ref_cache), err))
1948 strbuf_addf(err, "unable to resolve reference %s: %s",
1949 orig_refname, strerror(last_errno));
1950
1951 goto error_return;
1952 }
1953 /*
1954 * If the ref did not exist and we are creating it, make sure
1955 * there is no existing packed ref whose name begins with our
1956 * refname, nor a packed ref whose name is a proper prefix of
1957 * our refname.
1958 */
1959 if (is_null_oid(&lock->old_oid) &&
1960 verify_refname_available_dir(refname, extras, skip,
1961 get_packed_refs(&ref_cache), err)) {
1962 last_errno = ENOTDIR;
1963 goto error_return;
1964 }
1965
1966 lock->lk = xcalloc(1, sizeof(struct lock_file));
1967
1968 lflags = 0;
1969 if (flags & REF_NODEREF) {
1970 refname = orig_refname;
1971 lflags |= LOCK_NO_DEREF;
1972 }
1973 lock->ref_name = xstrdup(refname);
1974 lock->orig_ref_name = xstrdup(orig_refname);
1975 strbuf_git_path(&ref_file, "%s", refname);
1976
1977 retry:
1978 switch (safe_create_leading_directories_const(ref_file.buf)) {
1979 case SCLD_OK:
1980 break; /* success */
1981 case SCLD_VANISHED:
1982 if (--attempts_remaining > 0)
1983 goto retry;
1984 /* fall through */
1985 default:
1986 last_errno = errno;
1987 strbuf_addf(err, "unable to create directory for %s",
1988 ref_file.buf);
1989 goto error_return;
1990 }
1991
1992 if (hold_lock_file_for_update(lock->lk, ref_file.buf, lflags) < 0) {
1993 last_errno = errno;
1994 if (errno == ENOENT && --attempts_remaining > 0)
1995 /*
1996 * Maybe somebody just deleted one of the
1997 * directories leading to ref_file. Try
1998 * again:
1999 */
2000 goto retry;
2001 else {
2002 unable_to_lock_message(ref_file.buf, errno, err);
2003 goto error_return;
2004 }
2005 }
2006 if (old_sha1 && verify_lock(lock, old_sha1, mustexist, err)) {
2007 last_errno = errno;
2008 goto error_return;
2009 }
2010 goto out;
2011
2012 error_return:
2013 unlock_ref(lock);
2014 lock = NULL;
2015
2016 out:
2017 strbuf_release(&ref_file);
2018 strbuf_release(&orig_ref_file);
2019 errno = last_errno;
2020 return lock;
2021}
2022
2023/*
2024 * Write an entry to the packed-refs file for the specified refname.
2025 * If peeled is non-NULL, write it as the entry's peeled value.
2026 */
2027static void write_packed_entry(FILE *fh, char *refname, unsigned char *sha1,
2028 unsigned char *peeled)
2029{
2030 fprintf_or_die(fh, "%s %s\n", sha1_to_hex(sha1), refname);
2031 if (peeled)
2032 fprintf_or_die(fh, "^%s\n", sha1_to_hex(peeled));
2033}
2034
2035/*
2036 * An each_ref_entry_fn that writes the entry to a packed-refs file.
2037 */
2038static int write_packed_entry_fn(struct ref_entry *entry, void *cb_data)
2039{
2040 enum peel_status peel_status = peel_entry(entry, 0);
2041
2042 if (peel_status != PEEL_PEELED && peel_status != PEEL_NON_TAG)
2043 error("internal error: %s is not a valid packed reference!",
2044 entry->name);
2045 write_packed_entry(cb_data, entry->name, entry->u.value.oid.hash,
2046 peel_status == PEEL_PEELED ?
2047 entry->u.value.peeled.hash : NULL);
2048 return 0;
2049}
2050
2051/*
2052 * Lock the packed-refs file for writing. Flags is passed to
2053 * hold_lock_file_for_update(). Return 0 on success. On errors, set
2054 * errno appropriately and return a nonzero value.
2055 */
2056static int lock_packed_refs(int flags)
2057{
2058 static int timeout_configured = 0;
2059 static int timeout_value = 1000;
2060
2061 struct packed_ref_cache *packed_ref_cache;
2062
2063 if (!timeout_configured) {
2064 git_config_get_int("core.packedrefstimeout", &timeout_value);
2065 timeout_configured = 1;
2066 }
2067
2068 if (hold_lock_file_for_update_timeout(
2069 &packlock, git_path("packed-refs"),
2070 flags, timeout_value) < 0)
2071 return -1;
2072 /*
2073 * Get the current packed-refs while holding the lock. If the
2074 * packed-refs file has been modified since we last read it,
2075 * this will automatically invalidate the cache and re-read
2076 * the packed-refs file.
2077 */
2078 packed_ref_cache = get_packed_ref_cache(&ref_cache);
2079 packed_ref_cache->lock = &packlock;
2080 /* Increment the reference count to prevent it from being freed: */
2081 acquire_packed_ref_cache(packed_ref_cache);
2082 return 0;
2083}
2084
2085/*
2086 * Write the current version of the packed refs cache from memory to
2087 * disk. The packed-refs file must already be locked for writing (see
2088 * lock_packed_refs()). Return zero on success. On errors, set errno
2089 * and return a nonzero value
2090 */
2091static int commit_packed_refs(void)
2092{
2093 struct packed_ref_cache *packed_ref_cache =
2094 get_packed_ref_cache(&ref_cache);
2095 int error = 0;
2096 int save_errno = 0;
2097 FILE *out;
2098
2099 if (!packed_ref_cache->lock)
2100 die("internal error: packed-refs not locked");
2101
2102 out = fdopen_lock_file(packed_ref_cache->lock, "w");
2103 if (!out)
2104 die_errno("unable to fdopen packed-refs descriptor");
2105
2106 fprintf_or_die(out, "%s", PACKED_REFS_HEADER);
2107 do_for_each_entry_in_dir(get_packed_ref_dir(packed_ref_cache),
2108 0, write_packed_entry_fn, out);
2109
2110 if (commit_lock_file(packed_ref_cache->lock)) {
2111 save_errno = errno;
2112 error = -1;
2113 }
2114 packed_ref_cache->lock = NULL;
2115 release_packed_ref_cache(packed_ref_cache);
2116 errno = save_errno;
2117 return error;
2118}
2119
2120/*
2121 * Rollback the lockfile for the packed-refs file, and discard the
2122 * in-memory packed reference cache. (The packed-refs file will be
2123 * read anew if it is needed again after this function is called.)
2124 */
2125static void rollback_packed_refs(void)
2126{
2127 struct packed_ref_cache *packed_ref_cache =
2128 get_packed_ref_cache(&ref_cache);
2129
2130 if (!packed_ref_cache->lock)
2131 die("internal error: packed-refs not locked");
2132 rollback_lock_file(packed_ref_cache->lock);
2133 packed_ref_cache->lock = NULL;
2134 release_packed_ref_cache(packed_ref_cache);
2135 clear_packed_ref_cache(&ref_cache);
2136}
2137
2138struct ref_to_prune {
2139 struct ref_to_prune *next;
2140 unsigned char sha1[20];
2141 char name[FLEX_ARRAY];
2142};
2143
2144struct pack_refs_cb_data {
2145 unsigned int flags;
2146 struct ref_dir *packed_refs;
2147 struct ref_to_prune *ref_to_prune;
2148};
2149
2150/*
2151 * An each_ref_entry_fn that is run over loose references only. If
2152 * the loose reference can be packed, add an entry in the packed ref
2153 * cache. If the reference should be pruned, also add it to
2154 * ref_to_prune in the pack_refs_cb_data.
2155 */
2156static int pack_if_possible_fn(struct ref_entry *entry, void *cb_data)
2157{
2158 struct pack_refs_cb_data *cb = cb_data;
2159 enum peel_status peel_status;
2160 struct ref_entry *packed_entry;
2161 int is_tag_ref = starts_with(entry->name, "refs/tags/");
2162
2163 /* Do not pack per-worktree refs: */
2164 if (ref_type(entry->name) != REF_TYPE_NORMAL)
2165 return 0;
2166
2167 /* ALWAYS pack tags */
2168 if (!(cb->flags & PACK_REFS_ALL) && !is_tag_ref)
2169 return 0;
2170
2171 /* Do not pack symbolic or broken refs: */
2172 if ((entry->flag & REF_ISSYMREF) || !ref_resolves_to_object(entry))
2173 return 0;
2174
2175 /* Add a packed ref cache entry equivalent to the loose entry. */
2176 peel_status = peel_entry(entry, 1);
2177 if (peel_status != PEEL_PEELED && peel_status != PEEL_NON_TAG)
2178 die("internal error peeling reference %s (%s)",
2179 entry->name, oid_to_hex(&entry->u.value.oid));
2180 packed_entry = find_ref(cb->packed_refs, entry->name);
2181 if (packed_entry) {
2182 /* Overwrite existing packed entry with info from loose entry */
2183 packed_entry->flag = REF_ISPACKED | REF_KNOWS_PEELED;
2184 oidcpy(&packed_entry->u.value.oid, &entry->u.value.oid);
2185 } else {
2186 packed_entry = create_ref_entry(entry->name, entry->u.value.oid.hash,
2187 REF_ISPACKED | REF_KNOWS_PEELED, 0);
2188 add_ref(cb->packed_refs, packed_entry);
2189 }
2190 oidcpy(&packed_entry->u.value.peeled, &entry->u.value.peeled);
2191
2192 /* Schedule the loose reference for pruning if requested. */
2193 if ((cb->flags & PACK_REFS_PRUNE)) {
2194 int namelen = strlen(entry->name) + 1;
2195 struct ref_to_prune *n = xcalloc(1, sizeof(*n) + namelen);
2196 hashcpy(n->sha1, entry->u.value.oid.hash);
2197 memcpy(n->name, entry->name, namelen); /* includes NUL */
2198 n->next = cb->ref_to_prune;
2199 cb->ref_to_prune = n;
2200 }
2201 return 0;
2202}
2203
2204/*
2205 * Remove empty parents, but spare refs/ and immediate subdirs.
2206 * Note: munges *name.
2207 */
2208static void try_remove_empty_parents(char *name)
2209{
2210 char *p, *q;
2211 int i;
2212 p = name;
2213 for (i = 0; i < 2; i++) { /* refs/{heads,tags,...}/ */
2214 while (*p && *p != '/')
2215 p++;
2216 /* tolerate duplicate slashes; see check_refname_format() */
2217 while (*p == '/')
2218 p++;
2219 }
2220 for (q = p; *q; q++)
2221 ;
2222 while (1) {
2223 while (q > p && *q != '/')
2224 q--;
2225 while (q > p && *(q-1) == '/')
2226 q--;
2227 if (q == p)
2228 break;
2229 *q = '\0';
2230 if (rmdir(git_path("%s", name)))
2231 break;
2232 }
2233}
2234
2235/* make sure nobody touched the ref, and unlink */
2236static void prune_ref(struct ref_to_prune *r)
2237{
2238 struct ref_transaction *transaction;
2239 struct strbuf err = STRBUF_INIT;
2240
2241 if (check_refname_format(r->name, 0))
2242 return;
2243
2244 transaction = ref_transaction_begin(&err);
2245 if (!transaction ||
2246 ref_transaction_delete(transaction, r->name, r->sha1,
2247 REF_ISPRUNING, NULL, &err) ||
2248 ref_transaction_commit(transaction, &err)) {
2249 ref_transaction_free(transaction);
2250 error("%s", err.buf);
2251 strbuf_release(&err);
2252 return;
2253 }
2254 ref_transaction_free(transaction);
2255 strbuf_release(&err);
2256 try_remove_empty_parents(r->name);
2257}
2258
2259static void prune_refs(struct ref_to_prune *r)
2260{
2261 while (r) {
2262 prune_ref(r);
2263 r = r->next;
2264 }
2265}
2266
2267int pack_refs(unsigned int flags)
2268{
2269 struct pack_refs_cb_data cbdata;
2270
2271 memset(&cbdata, 0, sizeof(cbdata));
2272 cbdata.flags = flags;
2273
2274 lock_packed_refs(LOCK_DIE_ON_ERROR);
2275 cbdata.packed_refs = get_packed_refs(&ref_cache);
2276
2277 do_for_each_entry_in_dir(get_loose_refs(&ref_cache), 0,
2278 pack_if_possible_fn, &cbdata);
2279
2280 if (commit_packed_refs())
2281 die_errno("unable to overwrite old ref-pack file");
2282
2283 prune_refs(cbdata.ref_to_prune);
2284 return 0;
2285}
2286
2287/*
2288 * Rewrite the packed-refs file, omitting any refs listed in
2289 * 'refnames'. On error, leave packed-refs unchanged, write an error
2290 * message to 'err', and return a nonzero value.
2291 *
2292 * The refs in 'refnames' needn't be sorted. `err` must not be NULL.
2293 */
2294static int repack_without_refs(struct string_list *refnames, struct strbuf *err)
2295{
2296 struct ref_dir *packed;
2297 struct string_list_item *refname;
2298 int ret, needs_repacking = 0, removed = 0;
2299
2300 assert(err);
2301
2302 /* Look for a packed ref */
2303 for_each_string_list_item(refname, refnames) {
2304 if (get_packed_ref(refname->string)) {
2305 needs_repacking = 1;
2306 break;
2307 }
2308 }
2309
2310 /* Avoid locking if we have nothing to do */
2311 if (!needs_repacking)
2312 return 0; /* no refname exists in packed refs */
2313
2314 if (lock_packed_refs(0)) {
2315 unable_to_lock_message(git_path("packed-refs"), errno, err);
2316 return -1;
2317 }
2318 packed = get_packed_refs(&ref_cache);
2319
2320 /* Remove refnames from the cache */
2321 for_each_string_list_item(refname, refnames)
2322 if (remove_entry(packed, refname->string) != -1)
2323 removed = 1;
2324 if (!removed) {
2325 /*
2326 * All packed entries disappeared while we were
2327 * acquiring the lock.
2328 */
2329 rollback_packed_refs();
2330 return 0;
2331 }
2332
2333 /* Write what remains */
2334 ret = commit_packed_refs();
2335 if (ret)
2336 strbuf_addf(err, "unable to overwrite old ref-pack file: %s",
2337 strerror(errno));
2338 return ret;
2339}
2340
2341static int delete_ref_loose(struct ref_lock *lock, int flag, struct strbuf *err)
2342{
2343 assert(err);
2344
2345 if (!(flag & REF_ISPACKED) || flag & REF_ISSYMREF) {
2346 /*
2347 * loose. The loose file name is the same as the
2348 * lockfile name, minus ".lock":
2349 */
2350 char *loose_filename = get_locked_file_path(lock->lk);
2351 int res = unlink_or_msg(loose_filename, err);
2352 free(loose_filename);
2353 if (res)
2354 return 1;
2355 }
2356 return 0;
2357}
2358
2359int delete_refs(struct string_list *refnames)
2360{
2361 struct strbuf err = STRBUF_INIT;
2362 int i, result = 0;
2363
2364 if (!refnames->nr)
2365 return 0;
2366
2367 result = repack_without_refs(refnames, &err);
2368 if (result) {
2369 /*
2370 * If we failed to rewrite the packed-refs file, then
2371 * it is unsafe to try to remove loose refs, because
2372 * doing so might expose an obsolete packed value for
2373 * a reference that might even point at an object that
2374 * has been garbage collected.
2375 */
2376 if (refnames->nr == 1)
2377 error(_("could not delete reference %s: %s"),
2378 refnames->items[0].string, err.buf);
2379 else
2380 error(_("could not delete references: %s"), err.buf);
2381
2382 goto out;
2383 }
2384
2385 for (i = 0; i < refnames->nr; i++) {
2386 const char *refname = refnames->items[i].string;
2387
2388 if (delete_ref(refname, NULL, 0))
2389 result |= error(_("could not remove reference %s"), refname);
2390 }
2391
2392out:
2393 strbuf_release(&err);
2394 return result;
2395}
2396
2397/*
2398 * People using contrib's git-new-workdir have .git/logs/refs ->
2399 * /some/other/path/.git/logs/refs, and that may live on another device.
2400 *
2401 * IOW, to avoid cross device rename errors, the temporary renamed log must
2402 * live into logs/refs.
2403 */
2404#define TMP_RENAMED_LOG "logs/refs/.tmp-renamed-log"
2405
2406static int rename_tmp_log(const char *newrefname)
2407{
2408 int attempts_remaining = 4;
2409 struct strbuf path = STRBUF_INIT;
2410 int ret = -1;
2411
2412 retry:
2413 strbuf_reset(&path);
2414 strbuf_git_path(&path, "logs/%s", newrefname);
2415 switch (safe_create_leading_directories_const(path.buf)) {
2416 case SCLD_OK:
2417 break; /* success */
2418 case SCLD_VANISHED:
2419 if (--attempts_remaining > 0)
2420 goto retry;
2421 /* fall through */
2422 default:
2423 error("unable to create directory for %s", newrefname);
2424 goto out;
2425 }
2426
2427 if (rename(git_path(TMP_RENAMED_LOG), path.buf)) {
2428 if ((errno==EISDIR || errno==ENOTDIR) && --attempts_remaining > 0) {
2429 /*
2430 * rename(a, b) when b is an existing
2431 * directory ought to result in ISDIR, but
2432 * Solaris 5.8 gives ENOTDIR. Sheesh.
2433 */
2434 if (remove_empty_directories(&path)) {
2435 error("Directory not empty: logs/%s", newrefname);
2436 goto out;
2437 }
2438 goto retry;
2439 } else if (errno == ENOENT && --attempts_remaining > 0) {
2440 /*
2441 * Maybe another process just deleted one of
2442 * the directories in the path to newrefname.
2443 * Try again from the beginning.
2444 */
2445 goto retry;
2446 } else {
2447 error("unable to move logfile "TMP_RENAMED_LOG" to logs/%s: %s",
2448 newrefname, strerror(errno));
2449 goto out;
2450 }
2451 }
2452 ret = 0;
2453out:
2454 strbuf_release(&path);
2455 return ret;
2456}
2457
2458int verify_refname_available(const char *newname,
2459 struct string_list *extras,
2460 struct string_list *skip,
2461 struct strbuf *err)
2462{
2463 struct ref_dir *packed_refs = get_packed_refs(&ref_cache);
2464 struct ref_dir *loose_refs = get_loose_refs(&ref_cache);
2465
2466 if (verify_refname_available_dir(newname, extras, skip,
2467 packed_refs, err) ||
2468 verify_refname_available_dir(newname, extras, skip,
2469 loose_refs, err))
2470 return -1;
2471
2472 return 0;
2473}
2474
7bd9bcf3
MH
2475static int write_ref_to_lockfile(struct ref_lock *lock,
2476 const unsigned char *sha1, struct strbuf *err);
2477static int commit_ref_update(struct ref_lock *lock,
2478 const unsigned char *sha1, const char *logmsg,
2479 int flags, struct strbuf *err);
2480
2481int rename_ref(const char *oldrefname, const char *newrefname, const char *logmsg)
2482{
2483 unsigned char sha1[20], orig_sha1[20];
2484 int flag = 0, logmoved = 0;
2485 struct ref_lock *lock;
2486 struct stat loginfo;
2487 int log = !lstat(git_path("logs/%s", oldrefname), &loginfo);
2488 const char *symref = NULL;
2489 struct strbuf err = STRBUF_INIT;
2490
2491 if (log && S_ISLNK(loginfo.st_mode))
2492 return error("reflog for %s is a symlink", oldrefname);
2493
2494 symref = resolve_ref_unsafe(oldrefname, RESOLVE_REF_READING,
2495 orig_sha1, &flag);
2496 if (flag & REF_ISSYMREF)
2497 return error("refname %s is a symbolic ref, renaming it is not supported",
2498 oldrefname);
2499 if (!symref)
2500 return error("refname %s not found", oldrefname);
2501
2502 if (!rename_ref_available(oldrefname, newrefname))
2503 return 1;
2504
2505 if (log && rename(git_path("logs/%s", oldrefname), git_path(TMP_RENAMED_LOG)))
2506 return error("unable to move logfile logs/%s to "TMP_RENAMED_LOG": %s",
2507 oldrefname, strerror(errno));
2508
2509 if (delete_ref(oldrefname, orig_sha1, REF_NODEREF)) {
2510 error("unable to delete old %s", oldrefname);
2511 goto rollback;
2512 }
2513
2514 if (!read_ref_full(newrefname, RESOLVE_REF_READING, sha1, NULL) &&
2515 delete_ref(newrefname, sha1, REF_NODEREF)) {
2516 if (errno==EISDIR) {
2517 struct strbuf path = STRBUF_INIT;
2518 int result;
2519
2520 strbuf_git_path(&path, "%s", newrefname);
2521 result = remove_empty_directories(&path);
2522 strbuf_release(&path);
2523
2524 if (result) {
2525 error("Directory not empty: %s", newrefname);
2526 goto rollback;
2527 }
2528 } else {
2529 error("unable to delete existing %s", newrefname);
2530 goto rollback;
2531 }
2532 }
2533
2534 if (log && rename_tmp_log(newrefname))
2535 goto rollback;
2536
2537 logmoved = log;
2538
2539 lock = lock_ref_sha1_basic(newrefname, NULL, NULL, NULL, 0, NULL, &err);
2540 if (!lock) {
2541 error("unable to rename '%s' to '%s': %s", oldrefname, newrefname, err.buf);
2542 strbuf_release(&err);
2543 goto rollback;
2544 }
2545 hashcpy(lock->old_oid.hash, orig_sha1);
2546
2547 if (write_ref_to_lockfile(lock, orig_sha1, &err) ||
2548 commit_ref_update(lock, orig_sha1, logmsg, 0, &err)) {
2549 error("unable to write current sha1 into %s: %s", newrefname, err.buf);
2550 strbuf_release(&err);
2551 goto rollback;
2552 }
2553
2554 return 0;
2555
2556 rollback:
2557 lock = lock_ref_sha1_basic(oldrefname, NULL, NULL, NULL, 0, NULL, &err);
2558 if (!lock) {
2559 error("unable to lock %s for rollback: %s", oldrefname, err.buf);
2560 strbuf_release(&err);
2561 goto rollbacklog;
2562 }
2563
2564 flag = log_all_ref_updates;
2565 log_all_ref_updates = 0;
2566 if (write_ref_to_lockfile(lock, orig_sha1, &err) ||
2567 commit_ref_update(lock, orig_sha1, NULL, 0, &err)) {
2568 error("unable to write current sha1 into %s: %s", oldrefname, err.buf);
2569 strbuf_release(&err);
2570 }
2571 log_all_ref_updates = flag;
2572
2573 rollbacklog:
2574 if (logmoved && rename(git_path("logs/%s", newrefname), git_path("logs/%s", oldrefname)))
2575 error("unable to restore logfile %s from %s: %s",
2576 oldrefname, newrefname, strerror(errno));
2577 if (!logmoved && log &&
2578 rename(git_path(TMP_RENAMED_LOG), git_path("logs/%s", oldrefname)))
2579 error("unable to restore logfile %s from "TMP_RENAMED_LOG": %s",
2580 oldrefname, strerror(errno));
2581
2582 return 1;
2583}
2584
2585static int close_ref(struct ref_lock *lock)
2586{
2587 if (close_lock_file(lock->lk))
2588 return -1;
2589 return 0;
2590}
2591
2592static int commit_ref(struct ref_lock *lock)
2593{
2594 if (commit_lock_file(lock->lk))
2595 return -1;
2596 return 0;
2597}
2598
2599/*
2600 * Create a reflog for a ref. If force_create = 0, the reflog will
2601 * only be created for certain refs (those for which
2602 * should_autocreate_reflog returns non-zero. Otherwise, create it
2603 * regardless of the ref name. Fill in *err and return -1 on failure.
2604 */
2605static int log_ref_setup(const char *refname, struct strbuf *logfile, struct strbuf *err, int force_create)
2606{
2607 int logfd, oflags = O_APPEND | O_WRONLY;
2608
2609 strbuf_git_path(logfile, "logs/%s", refname);
2610 if (force_create || should_autocreate_reflog(refname)) {
2611 if (safe_create_leading_directories(logfile->buf) < 0) {
2612 strbuf_addf(err, "unable to create directory for %s: "
2613 "%s", logfile->buf, strerror(errno));
2614 return -1;
2615 }
2616 oflags |= O_CREAT;
2617 }
2618
2619 logfd = open(logfile->buf, oflags, 0666);
2620 if (logfd < 0) {
2621 if (!(oflags & O_CREAT) && (errno == ENOENT || errno == EISDIR))
2622 return 0;
2623
2624 if (errno == EISDIR) {
2625 if (remove_empty_directories(logfile)) {
2626 strbuf_addf(err, "There are still logs under "
2627 "'%s'", logfile->buf);
2628 return -1;
2629 }
2630 logfd = open(logfile->buf, oflags, 0666);
2631 }
2632
2633 if (logfd < 0) {
2634 strbuf_addf(err, "unable to append to %s: %s",
2635 logfile->buf, strerror(errno));
2636 return -1;
2637 }
2638 }
2639
2640 adjust_shared_perm(logfile->buf);
2641 close(logfd);
2642 return 0;
2643}
2644
2645
2646int safe_create_reflog(const char *refname, int force_create, struct strbuf *err)
2647{
2648 int ret;
2649 struct strbuf sb = STRBUF_INIT;
2650
2651 ret = log_ref_setup(refname, &sb, err, force_create);
2652 strbuf_release(&sb);
2653 return ret;
2654}
2655
2656static int log_ref_write_fd(int fd, const unsigned char *old_sha1,
2657 const unsigned char *new_sha1,
2658 const char *committer, const char *msg)
2659{
2660 int msglen, written;
2661 unsigned maxlen, len;
2662 char *logrec;
2663
2664 msglen = msg ? strlen(msg) : 0;
2665 maxlen = strlen(committer) + msglen + 100;
2666 logrec = xmalloc(maxlen);
2667 len = xsnprintf(logrec, maxlen, "%s %s %s\n",
2668 sha1_to_hex(old_sha1),
2669 sha1_to_hex(new_sha1),
2670 committer);
2671 if (msglen)
2672 len += copy_reflog_msg(logrec + len - 1, msg) - 1;
2673
2674 written = len <= maxlen ? write_in_full(fd, logrec, len) : -1;
2675 free(logrec);
2676 if (written != len)
2677 return -1;
2678
2679 return 0;
2680}
2681
2682static int log_ref_write_1(const char *refname, const unsigned char *old_sha1,
2683 const unsigned char *new_sha1, const char *msg,
2684 struct strbuf *logfile, int flags,
2685 struct strbuf *err)
2686{
2687 int logfd, result, oflags = O_APPEND | O_WRONLY;
2688
2689 if (log_all_ref_updates < 0)
2690 log_all_ref_updates = !is_bare_repository();
2691
2692 result = log_ref_setup(refname, logfile, err, flags & REF_FORCE_CREATE_REFLOG);
2693
2694 if (result)
2695 return result;
2696
2697 logfd = open(logfile->buf, oflags);
2698 if (logfd < 0)
2699 return 0;
2700 result = log_ref_write_fd(logfd, old_sha1, new_sha1,
2701 git_committer_info(0), msg);
2702 if (result) {
2703 strbuf_addf(err, "unable to append to %s: %s", logfile->buf,
2704 strerror(errno));
2705 close(logfd);
2706 return -1;
2707 }
2708 if (close(logfd)) {
2709 strbuf_addf(err, "unable to append to %s: %s", logfile->buf,
2710 strerror(errno));
2711 return -1;
2712 }
2713 return 0;
2714}
2715
2716static int log_ref_write(const char *refname, const unsigned char *old_sha1,
2717 const unsigned char *new_sha1, const char *msg,
2718 int flags, struct strbuf *err)
5f3c3a4e
DT
2719{
2720 return files_log_ref_write(refname, old_sha1, new_sha1, msg, flags,
2721 err);
2722}
2723
2724int files_log_ref_write(const char *refname, const unsigned char *old_sha1,
2725 const unsigned char *new_sha1, const char *msg,
2726 int flags, struct strbuf *err)
7bd9bcf3
MH
2727{
2728 struct strbuf sb = STRBUF_INIT;
2729 int ret = log_ref_write_1(refname, old_sha1, new_sha1, msg, &sb, flags,
2730 err);
2731 strbuf_release(&sb);
2732 return ret;
2733}
2734
2735/*
2736 * Write sha1 into the open lockfile, then close the lockfile. On
2737 * errors, rollback the lockfile, fill in *err and
2738 * return -1.
2739 */
2740static int write_ref_to_lockfile(struct ref_lock *lock,
2741 const unsigned char *sha1, struct strbuf *err)
2742{
2743 static char term = '\n';
2744 struct object *o;
2745 int fd;
2746
2747 o = parse_object(sha1);
2748 if (!o) {
2749 strbuf_addf(err,
2750 "Trying to write ref %s with nonexistent object %s",
2751 lock->ref_name, sha1_to_hex(sha1));
2752 unlock_ref(lock);
2753 return -1;
2754 }
2755 if (o->type != OBJ_COMMIT && is_branch(lock->ref_name)) {
2756 strbuf_addf(err,
2757 "Trying to write non-commit object %s to branch %s",
2758 sha1_to_hex(sha1), lock->ref_name);
2759 unlock_ref(lock);
2760 return -1;
2761 }
2762 fd = get_lock_file_fd(lock->lk);
2763 if (write_in_full(fd, sha1_to_hex(sha1), 40) != 40 ||
2764 write_in_full(fd, &term, 1) != 1 ||
2765 close_ref(lock) < 0) {
2766 strbuf_addf(err,
2767 "Couldn't write %s", get_lock_file_path(lock->lk));
2768 unlock_ref(lock);
2769 return -1;
2770 }
2771 return 0;
2772}
2773
2774/*
2775 * Commit a change to a loose reference that has already been written
2776 * to the loose reference lockfile. Also update the reflogs if
2777 * necessary, using the specified lockmsg (which can be NULL).
2778 */
2779static int commit_ref_update(struct ref_lock *lock,
2780 const unsigned char *sha1, const char *logmsg,
2781 int flags, struct strbuf *err)
2782{
2783 clear_loose_ref_cache(&ref_cache);
2784 if (log_ref_write(lock->ref_name, lock->old_oid.hash, sha1, logmsg, flags, err) < 0 ||
2785 (strcmp(lock->ref_name, lock->orig_ref_name) &&
2786 log_ref_write(lock->orig_ref_name, lock->old_oid.hash, sha1, logmsg, flags, err) < 0)) {
2787 char *old_msg = strbuf_detach(err, NULL);
2788 strbuf_addf(err, "Cannot update the ref '%s': %s",
2789 lock->ref_name, old_msg);
2790 free(old_msg);
2791 unlock_ref(lock);
2792 return -1;
2793 }
2794 if (strcmp(lock->orig_ref_name, "HEAD") != 0) {
2795 /*
2796 * Special hack: If a branch is updated directly and HEAD
2797 * points to it (may happen on the remote side of a push
2798 * for example) then logically the HEAD reflog should be
2799 * updated too.
2800 * A generic solution implies reverse symref information,
2801 * but finding all symrefs pointing to the given branch
2802 * would be rather costly for this rare event (the direct
2803 * update of a branch) to be worth it. So let's cheat and
2804 * check with HEAD only which should cover 99% of all usage
2805 * scenarios (even 100% of the default ones).
2806 */
2807 unsigned char head_sha1[20];
2808 int head_flag;
2809 const char *head_ref;
2810 head_ref = resolve_ref_unsafe("HEAD", RESOLVE_REF_READING,
2811 head_sha1, &head_flag);
2812 if (head_ref && (head_flag & REF_ISSYMREF) &&
2813 !strcmp(head_ref, lock->ref_name)) {
2814 struct strbuf log_err = STRBUF_INIT;
2815 if (log_ref_write("HEAD", lock->old_oid.hash, sha1,
2816 logmsg, 0, &log_err)) {
2817 error("%s", log_err.buf);
2818 strbuf_release(&log_err);
2819 }
2820 }
2821 }
2822 if (commit_ref(lock)) {
2823 error("Couldn't set %s", lock->ref_name);
2824 unlock_ref(lock);
2825 return -1;
2826 }
2827
2828 unlock_ref(lock);
2829 return 0;
2830}
2831
2832int create_symref(const char *ref_target, const char *refs_heads_master,
2833 const char *logmsg)
2834{
2835 char *lockpath = NULL;
2836 char ref[1000];
2837 int fd, len, written;
2838 char *git_HEAD = git_pathdup("%s", ref_target);
2839 unsigned char old_sha1[20], new_sha1[20];
2840 struct strbuf err = STRBUF_INIT;
2841
2842 if (logmsg && read_ref(ref_target, old_sha1))
2843 hashclr(old_sha1);
2844
2845 if (safe_create_leading_directories(git_HEAD) < 0)
2846 return error("unable to create directory for %s", git_HEAD);
2847
2848#ifndef NO_SYMLINK_HEAD
2849 if (prefer_symlink_refs) {
2850 unlink(git_HEAD);
2851 if (!symlink(refs_heads_master, git_HEAD))
2852 goto done;
2853 fprintf(stderr, "no symlink - falling back to symbolic ref\n");
2854 }
2855#endif
2856
2857 len = snprintf(ref, sizeof(ref), "ref: %s\n", refs_heads_master);
2858 if (sizeof(ref) <= len) {
2859 error("refname too long: %s", refs_heads_master);
2860 goto error_free_return;
2861 }
2862 lockpath = mkpathdup("%s.lock", git_HEAD);
2863 fd = open(lockpath, O_CREAT | O_EXCL | O_WRONLY, 0666);
2864 if (fd < 0) {
2865 error("Unable to open %s for writing", lockpath);
2866 goto error_free_return;
2867 }
2868 written = write_in_full(fd, ref, len);
2869 if (close(fd) != 0 || written != len) {
2870 error("Unable to write to %s", lockpath);
2871 goto error_unlink_return;
2872 }
2873 if (rename(lockpath, git_HEAD) < 0) {
2874 error("Unable to create %s", git_HEAD);
2875 goto error_unlink_return;
2876 }
2877 if (adjust_shared_perm(git_HEAD)) {
2878 error("Unable to fix permissions on %s", lockpath);
2879 error_unlink_return:
2880 unlink_or_warn(lockpath);
2881 error_free_return:
2882 free(lockpath);
2883 free(git_HEAD);
2884 return -1;
2885 }
2886 free(lockpath);
2887
2888#ifndef NO_SYMLINK_HEAD
2889 done:
2890#endif
2891 if (logmsg && !read_ref(refs_heads_master, new_sha1) &&
2892 log_ref_write(ref_target, old_sha1, new_sha1, logmsg, 0, &err)) {
2893 error("%s", err.buf);
2894 strbuf_release(&err);
2895 }
2896
2897 free(git_HEAD);
2898 return 0;
2899}
2900
2901int reflog_exists(const char *refname)
2902{
2903 struct stat st;
2904
2905 return !lstat(git_path("logs/%s", refname), &st) &&
2906 S_ISREG(st.st_mode);
2907}
2908
2909int delete_reflog(const char *refname)
2910{
2911 return remove_path(git_path("logs/%s", refname));
2912}
2913
2914static int show_one_reflog_ent(struct strbuf *sb, each_reflog_ent_fn fn, void *cb_data)
2915{
2916 unsigned char osha1[20], nsha1[20];
2917 char *email_end, *message;
2918 unsigned long timestamp;
2919 int tz;
2920
2921 /* old SP new SP name <email> SP time TAB msg LF */
2922 if (sb->len < 83 || sb->buf[sb->len - 1] != '\n' ||
2923 get_sha1_hex(sb->buf, osha1) || sb->buf[40] != ' ' ||
2924 get_sha1_hex(sb->buf + 41, nsha1) || sb->buf[81] != ' ' ||
2925 !(email_end = strchr(sb->buf + 82, '>')) ||
2926 email_end[1] != ' ' ||
2927 !(timestamp = strtoul(email_end + 2, &message, 10)) ||
2928 !message || message[0] != ' ' ||
2929 (message[1] != '+' && message[1] != '-') ||
2930 !isdigit(message[2]) || !isdigit(message[3]) ||
2931 !isdigit(message[4]) || !isdigit(message[5]))
2932 return 0; /* corrupt? */
2933 email_end[1] = '\0';
2934 tz = strtol(message + 1, NULL, 10);
2935 if (message[6] != '\t')
2936 message += 6;
2937 else
2938 message += 7;
2939 return fn(osha1, nsha1, sb->buf + 82, timestamp, tz, message, cb_data);
2940}
2941
2942static char *find_beginning_of_line(char *bob, char *scan)
2943{
2944 while (bob < scan && *(--scan) != '\n')
2945 ; /* keep scanning backwards */
2946 /*
2947 * Return either beginning of the buffer, or LF at the end of
2948 * the previous line.
2949 */
2950 return scan;
2951}
2952
2953int for_each_reflog_ent_reverse(const char *refname, each_reflog_ent_fn fn, void *cb_data)
2954{
2955 struct strbuf sb = STRBUF_INIT;
2956 FILE *logfp;
2957 long pos;
2958 int ret = 0, at_tail = 1;
2959
2960 logfp = fopen(git_path("logs/%s", refname), "r");
2961 if (!logfp)
2962 return -1;
2963
2964 /* Jump to the end */
2965 if (fseek(logfp, 0, SEEK_END) < 0)
2966 return error("cannot seek back reflog for %s: %s",
2967 refname, strerror(errno));
2968 pos = ftell(logfp);
2969 while (!ret && 0 < pos) {
2970 int cnt;
2971 size_t nread;
2972 char buf[BUFSIZ];
2973 char *endp, *scanp;
2974
2975 /* Fill next block from the end */
2976 cnt = (sizeof(buf) < pos) ? sizeof(buf) : pos;
2977 if (fseek(logfp, pos - cnt, SEEK_SET))
2978 return error("cannot seek back reflog for %s: %s",
2979 refname, strerror(errno));
2980 nread = fread(buf, cnt, 1, logfp);
2981 if (nread != 1)
2982 return error("cannot read %d bytes from reflog for %s: %s",
2983 cnt, refname, strerror(errno));
2984 pos -= cnt;
2985
2986 scanp = endp = buf + cnt;
2987 if (at_tail && scanp[-1] == '\n')
2988 /* Looking at the final LF at the end of the file */
2989 scanp--;
2990 at_tail = 0;
2991
2992 while (buf < scanp) {
2993 /*
2994 * terminating LF of the previous line, or the beginning
2995 * of the buffer.
2996 */
2997 char *bp;
2998
2999 bp = find_beginning_of_line(buf, scanp);
3000
3001 if (*bp == '\n') {
3002 /*
3003 * The newline is the end of the previous line,
3004 * so we know we have complete line starting
3005 * at (bp + 1). Prefix it onto any prior data
3006 * we collected for the line and process it.
3007 */
3008 strbuf_splice(&sb, 0, 0, bp + 1, endp - (bp + 1));
3009 scanp = bp;
3010 endp = bp + 1;
3011 ret = show_one_reflog_ent(&sb, fn, cb_data);
3012 strbuf_reset(&sb);
3013 if (ret)
3014 break;
3015 } else if (!pos) {
3016 /*
3017 * We are at the start of the buffer, and the
3018 * start of the file; there is no previous
3019 * line, and we have everything for this one.
3020 * Process it, and we can end the loop.
3021 */
3022 strbuf_splice(&sb, 0, 0, buf, endp - buf);
3023 ret = show_one_reflog_ent(&sb, fn, cb_data);
3024 strbuf_reset(&sb);
3025 break;
3026 }
3027
3028 if (bp == buf) {
3029 /*
3030 * We are at the start of the buffer, and there
3031 * is more file to read backwards. Which means
3032 * we are in the middle of a line. Note that we
3033 * may get here even if *bp was a newline; that
3034 * just means we are at the exact end of the
3035 * previous line, rather than some spot in the
3036 * middle.
3037 *
3038 * Save away what we have to be combined with
3039 * the data from the next read.
3040 */
3041 strbuf_splice(&sb, 0, 0, buf, endp - buf);
3042 break;
3043 }
3044 }
3045
3046 }
3047 if (!ret && sb.len)
3048 die("BUG: reverse reflog parser had leftover data");
3049
3050 fclose(logfp);
3051 strbuf_release(&sb);
3052 return ret;
3053}
3054
3055int for_each_reflog_ent(const char *refname, each_reflog_ent_fn fn, void *cb_data)
3056{
3057 FILE *logfp;
3058 struct strbuf sb = STRBUF_INIT;
3059 int ret = 0;
3060
3061 logfp = fopen(git_path("logs/%s", refname), "r");
3062 if (!logfp)
3063 return -1;
3064
3065 while (!ret && !strbuf_getwholeline(&sb, logfp, '\n'))
3066 ret = show_one_reflog_ent(&sb, fn, cb_data);
3067 fclose(logfp);
3068 strbuf_release(&sb);
3069 return ret;
3070}
3071/*
3072 * Call fn for each reflog in the namespace indicated by name. name
3073 * must be empty or end with '/'. Name will be used as a scratch
3074 * space, but its contents will be restored before return.
3075 */
3076static int do_for_each_reflog(struct strbuf *name, each_ref_fn fn, void *cb_data)
3077{
3078 DIR *d = opendir(git_path("logs/%s", name->buf));
3079 int retval = 0;
3080 struct dirent *de;
3081 int oldlen = name->len;
3082
3083 if (!d)
3084 return name->len ? errno : 0;
3085
3086 while ((de = readdir(d)) != NULL) {
3087 struct stat st;
3088
3089 if (de->d_name[0] == '.')
3090 continue;
3091 if (ends_with(de->d_name, ".lock"))
3092 continue;
3093 strbuf_addstr(name, de->d_name);
3094 if (stat(git_path("logs/%s", name->buf), &st) < 0) {
3095 ; /* silently ignore */
3096 } else {
3097 if (S_ISDIR(st.st_mode)) {
3098 strbuf_addch(name, '/');
3099 retval = do_for_each_reflog(name, fn, cb_data);
3100 } else {
3101 struct object_id oid;
3102
3103 if (read_ref_full(name->buf, 0, oid.hash, NULL))
3104 retval = error("bad ref for %s", name->buf);
3105 else
3106 retval = fn(name->buf, &oid, 0, cb_data);
3107 }
3108 if (retval)
3109 break;
3110 }
3111 strbuf_setlen(name, oldlen);
3112 }
3113 closedir(d);
3114 return retval;
3115}
3116
3117int for_each_reflog(each_ref_fn fn, void *cb_data)
3118{
3119 int retval;
3120 struct strbuf name;
3121 strbuf_init(&name, PATH_MAX);
3122 retval = do_for_each_reflog(&name, fn, cb_data);
3123 strbuf_release(&name);
3124 return retval;
3125}
3126
3127static int ref_update_reject_duplicates(struct string_list *refnames,
3128 struct strbuf *err)
3129{
3130 int i, n = refnames->nr;
3131
3132 assert(err);
3133
3134 for (i = 1; i < n; i++)
3135 if (!strcmp(refnames->items[i - 1].string, refnames->items[i].string)) {
3136 strbuf_addf(err,
3137 "Multiple updates for ref '%s' not allowed.",
3138 refnames->items[i].string);
3139 return 1;
3140 }
3141 return 0;
3142}
3143
3144int ref_transaction_commit(struct ref_transaction *transaction,
3145 struct strbuf *err)
3146{
3147 int ret = 0, i;
3148 int n = transaction->nr;
3149 struct ref_update **updates = transaction->updates;
3150 struct string_list refs_to_delete = STRING_LIST_INIT_NODUP;
3151 struct string_list_item *ref_to_delete;
3152 struct string_list affected_refnames = STRING_LIST_INIT_NODUP;
3153
3154 assert(err);
3155
3156 if (transaction->state != REF_TRANSACTION_OPEN)
3157 die("BUG: commit called for transaction that is not open");
3158
3159 if (!n) {
3160 transaction->state = REF_TRANSACTION_CLOSED;
3161 return 0;
3162 }
3163
3164 /* Fail if a refname appears more than once in the transaction: */
3165 for (i = 0; i < n; i++)
3166 string_list_append(&affected_refnames, updates[i]->refname);
3167 string_list_sort(&affected_refnames);
3168 if (ref_update_reject_duplicates(&affected_refnames, err)) {
3169 ret = TRANSACTION_GENERIC_ERROR;
3170 goto cleanup;
3171 }
3172
3173 /*
3174 * Acquire all locks, verify old values if provided, check
3175 * that new values are valid, and write new values to the
3176 * lockfiles, ready to be activated. Only keep one lockfile
3177 * open at a time to avoid running out of file descriptors.
3178 */
3179 for (i = 0; i < n; i++) {
3180 struct ref_update *update = updates[i];
3181
3182 if ((update->flags & REF_HAVE_NEW) &&
3183 is_null_sha1(update->new_sha1))
3184 update->flags |= REF_DELETING;
3185 update->lock = lock_ref_sha1_basic(
3186 update->refname,
3187 ((update->flags & REF_HAVE_OLD) ?
3188 update->old_sha1 : NULL),
3189 &affected_refnames, NULL,
3190 update->flags,
3191 &update->type,
3192 err);
3193 if (!update->lock) {
3194 char *reason;
3195
3196 ret = (errno == ENOTDIR)
3197 ? TRANSACTION_NAME_CONFLICT
3198 : TRANSACTION_GENERIC_ERROR;
3199 reason = strbuf_detach(err, NULL);
3200 strbuf_addf(err, "cannot lock ref '%s': %s",
3201 update->refname, reason);
3202 free(reason);
3203 goto cleanup;
3204 }
3205 if ((update->flags & REF_HAVE_NEW) &&
3206 !(update->flags & REF_DELETING)) {
3207 int overwriting_symref = ((update->type & REF_ISSYMREF) &&
3208 (update->flags & REF_NODEREF));
3209
3210 if (!overwriting_symref &&
3211 !hashcmp(update->lock->old_oid.hash, update->new_sha1)) {
3212 /*
3213 * The reference already has the desired
3214 * value, so we don't need to write it.
3215 */
3216 } else if (write_ref_to_lockfile(update->lock,
3217 update->new_sha1,
3218 err)) {
3219 char *write_err = strbuf_detach(err, NULL);
3220
3221 /*
3222 * The lock was freed upon failure of
3223 * write_ref_to_lockfile():
3224 */
3225 update->lock = NULL;
3226 strbuf_addf(err,
3227 "cannot update the ref '%s': %s",
3228 update->refname, write_err);
3229 free(write_err);
3230 ret = TRANSACTION_GENERIC_ERROR;
3231 goto cleanup;
3232 } else {
3233 update->flags |= REF_NEEDS_COMMIT;
3234 }
3235 }
3236 if (!(update->flags & REF_NEEDS_COMMIT)) {
3237 /*
3238 * We didn't have to write anything to the lockfile.
3239 * Close it to free up the file descriptor:
3240 */
3241 if (close_ref(update->lock)) {
3242 strbuf_addf(err, "Couldn't close %s.lock",
3243 update->refname);
3244 goto cleanup;
3245 }
3246 }
3247 }
3248
3249 /* Perform updates first so live commits remain referenced */
3250 for (i = 0; i < n; i++) {
3251 struct ref_update *update = updates[i];
3252
3253 if (update->flags & REF_NEEDS_COMMIT) {
3254 if (commit_ref_update(update->lock,
3255 update->new_sha1, update->msg,
3256 update->flags, err)) {
3257 /* freed by commit_ref_update(): */
3258 update->lock = NULL;
3259 ret = TRANSACTION_GENERIC_ERROR;
3260 goto cleanup;
3261 } else {
3262 /* freed by commit_ref_update(): */
3263 update->lock = NULL;
3264 }
3265 }
3266 }
3267
3268 /* Perform deletes now that updates are safely completed */
3269 for (i = 0; i < n; i++) {
3270 struct ref_update *update = updates[i];
3271
3272 if (update->flags & REF_DELETING) {
3273 if (delete_ref_loose(update->lock, update->type, err)) {
3274 ret = TRANSACTION_GENERIC_ERROR;
3275 goto cleanup;
3276 }
3277
3278 if (!(update->flags & REF_ISPRUNING))
3279 string_list_append(&refs_to_delete,
3280 update->lock->ref_name);
3281 }
3282 }
3283
3284 if (repack_without_refs(&refs_to_delete, err)) {
3285 ret = TRANSACTION_GENERIC_ERROR;
3286 goto cleanup;
3287 }
3288 for_each_string_list_item(ref_to_delete, &refs_to_delete)
3289 unlink_or_warn(git_path("logs/%s", ref_to_delete->string));
3290 clear_loose_ref_cache(&ref_cache);
3291
3292cleanup:
3293 transaction->state = REF_TRANSACTION_CLOSED;
3294
3295 for (i = 0; i < n; i++)
3296 if (updates[i]->lock)
3297 unlock_ref(updates[i]->lock);
3298 string_list_clear(&refs_to_delete, 0);
3299 string_list_clear(&affected_refnames, 0);
3300 return ret;
3301}
3302
3303static int ref_present(const char *refname,
3304 const struct object_id *oid, int flags, void *cb_data)
3305{
3306 struct string_list *affected_refnames = cb_data;
3307
3308 return string_list_has_string(affected_refnames, refname);
3309}
3310
3311int initial_ref_transaction_commit(struct ref_transaction *transaction,
3312 struct strbuf *err)
3313{
3314 int ret = 0, i;
3315 int n = transaction->nr;
3316 struct ref_update **updates = transaction->updates;
3317 struct string_list affected_refnames = STRING_LIST_INIT_NODUP;
3318
3319 assert(err);
3320
3321 if (transaction->state != REF_TRANSACTION_OPEN)
3322 die("BUG: commit called for transaction that is not open");
3323
3324 /* Fail if a refname appears more than once in the transaction: */
3325 for (i = 0; i < n; i++)
3326 string_list_append(&affected_refnames, updates[i]->refname);
3327 string_list_sort(&affected_refnames);
3328 if (ref_update_reject_duplicates(&affected_refnames, err)) {
3329 ret = TRANSACTION_GENERIC_ERROR;
3330 goto cleanup;
3331 }
3332
3333 /*
3334 * It's really undefined to call this function in an active
3335 * repository or when there are existing references: we are
3336 * only locking and changing packed-refs, so (1) any
3337 * simultaneous processes might try to change a reference at
3338 * the same time we do, and (2) any existing loose versions of
3339 * the references that we are setting would have precedence
3340 * over our values. But some remote helpers create the remote
3341 * "HEAD" and "master" branches before calling this function,
3342 * so here we really only check that none of the references
3343 * that we are creating already exists.
3344 */
3345 if (for_each_rawref(ref_present, &affected_refnames))
3346 die("BUG: initial ref transaction called with existing refs");
3347
3348 for (i = 0; i < n; i++) {
3349 struct ref_update *update = updates[i];
3350
3351 if ((update->flags & REF_HAVE_OLD) &&
3352 !is_null_sha1(update->old_sha1))
3353 die("BUG: initial ref transaction with old_sha1 set");
3354 if (verify_refname_available(update->refname,
3355 &affected_refnames, NULL,
3356 err)) {
3357 ret = TRANSACTION_NAME_CONFLICT;
3358 goto cleanup;
3359 }
3360 }
3361
3362 if (lock_packed_refs(0)) {
3363 strbuf_addf(err, "unable to lock packed-refs file: %s",
3364 strerror(errno));
3365 ret = TRANSACTION_GENERIC_ERROR;
3366 goto cleanup;
3367 }
3368
3369 for (i = 0; i < n; i++) {
3370 struct ref_update *update = updates[i];
3371
3372 if ((update->flags & REF_HAVE_NEW) &&
3373 !is_null_sha1(update->new_sha1))
3374 add_packed_ref(update->refname, update->new_sha1);
3375 }
3376
3377 if (commit_packed_refs()) {
3378 strbuf_addf(err, "unable to commit packed-refs file: %s",
3379 strerror(errno));
3380 ret = TRANSACTION_GENERIC_ERROR;
3381 goto cleanup;
3382 }
3383
3384cleanup:
3385 transaction->state = REF_TRANSACTION_CLOSED;
3386 string_list_clear(&affected_refnames, 0);
3387 return ret;
3388}
3389
3390struct expire_reflog_cb {
3391 unsigned int flags;
3392 reflog_expiry_should_prune_fn *should_prune_fn;
3393 void *policy_cb;
3394 FILE *newlog;
3395 unsigned char last_kept_sha1[20];
3396};
3397
3398static int expire_reflog_ent(unsigned char *osha1, unsigned char *nsha1,
3399 const char *email, unsigned long timestamp, int tz,
3400 const char *message, void *cb_data)
3401{
3402 struct expire_reflog_cb *cb = cb_data;
3403 struct expire_reflog_policy_cb *policy_cb = cb->policy_cb;
3404
3405 if (cb->flags & EXPIRE_REFLOGS_REWRITE)
3406 osha1 = cb->last_kept_sha1;
3407
3408 if ((*cb->should_prune_fn)(osha1, nsha1, email, timestamp, tz,
3409 message, policy_cb)) {
3410 if (!cb->newlog)
3411 printf("would prune %s", message);
3412 else if (cb->flags & EXPIRE_REFLOGS_VERBOSE)
3413 printf("prune %s", message);
3414 } else {
3415 if (cb->newlog) {
3416 fprintf(cb->newlog, "%s %s %s %lu %+05d\t%s",
3417 sha1_to_hex(osha1), sha1_to_hex(nsha1),
3418 email, timestamp, tz, message);
3419 hashcpy(cb->last_kept_sha1, nsha1);
3420 }
3421 if (cb->flags & EXPIRE_REFLOGS_VERBOSE)
3422 printf("keep %s", message);
3423 }
3424 return 0;
3425}
3426
3427int reflog_expire(const char *refname, const unsigned char *sha1,
3428 unsigned int flags,
3429 reflog_expiry_prepare_fn prepare_fn,
3430 reflog_expiry_should_prune_fn should_prune_fn,
3431 reflog_expiry_cleanup_fn cleanup_fn,
3432 void *policy_cb_data)
3433{
3434 static struct lock_file reflog_lock;
3435 struct expire_reflog_cb cb;
3436 struct ref_lock *lock;
3437 char *log_file;
3438 int status = 0;
3439 int type;
3440 struct strbuf err = STRBUF_INIT;
3441
3442 memset(&cb, 0, sizeof(cb));
3443 cb.flags = flags;
3444 cb.policy_cb = policy_cb_data;
3445 cb.should_prune_fn = should_prune_fn;
3446
3447 /*
3448 * The reflog file is locked by holding the lock on the
3449 * reference itself, plus we might need to update the
3450 * reference if --updateref was specified:
3451 */
3452 lock = lock_ref_sha1_basic(refname, sha1, NULL, NULL, 0, &type, &err);
3453 if (!lock) {
3454 error("cannot lock ref '%s': %s", refname, err.buf);
3455 strbuf_release(&err);
3456 return -1;
3457 }
3458 if (!reflog_exists(refname)) {
3459 unlock_ref(lock);
3460 return 0;
3461 }
3462
3463 log_file = git_pathdup("logs/%s", refname);
3464 if (!(flags & EXPIRE_REFLOGS_DRY_RUN)) {
3465 /*
3466 * Even though holding $GIT_DIR/logs/$reflog.lock has
3467 * no locking implications, we use the lock_file
3468 * machinery here anyway because it does a lot of the
3469 * work we need, including cleaning up if the program
3470 * exits unexpectedly.
3471 */
3472 if (hold_lock_file_for_update(&reflog_lock, log_file, 0) < 0) {
3473 struct strbuf err = STRBUF_INIT;
3474 unable_to_lock_message(log_file, errno, &err);
3475 error("%s", err.buf);
3476 strbuf_release(&err);
3477 goto failure;
3478 }
3479 cb.newlog = fdopen_lock_file(&reflog_lock, "w");
3480 if (!cb.newlog) {
3481 error("cannot fdopen %s (%s)",
3482 get_lock_file_path(&reflog_lock), strerror(errno));
3483 goto failure;
3484 }
3485 }
3486
3487 (*prepare_fn)(refname, sha1, cb.policy_cb);
3488 for_each_reflog_ent(refname, expire_reflog_ent, &cb);
3489 (*cleanup_fn)(cb.policy_cb);
3490
3491 if (!(flags & EXPIRE_REFLOGS_DRY_RUN)) {
3492 /*
3493 * It doesn't make sense to adjust a reference pointed
3494 * to by a symbolic ref based on expiring entries in
3495 * the symbolic reference's reflog. Nor can we update
3496 * a reference if there are no remaining reflog
3497 * entries.
3498 */
3499 int update = (flags & EXPIRE_REFLOGS_UPDATE_REF) &&
3500 !(type & REF_ISSYMREF) &&
3501 !is_null_sha1(cb.last_kept_sha1);
3502
3503 if (close_lock_file(&reflog_lock)) {
3504 status |= error("couldn't write %s: %s", log_file,
3505 strerror(errno));
3506 } else if (update &&
3507 (write_in_full(get_lock_file_fd(lock->lk),
3508 sha1_to_hex(cb.last_kept_sha1), 40) != 40 ||
3509 write_str_in_full(get_lock_file_fd(lock->lk), "\n") != 1 ||
3510 close_ref(lock) < 0)) {
3511 status |= error("couldn't write %s",
3512 get_lock_file_path(lock->lk));
3513 rollback_lock_file(&reflog_lock);
3514 } else if (commit_lock_file(&reflog_lock)) {
e0048d3e 3515 status |= error("unable to write reflog '%s' (%s)",
7bd9bcf3
MH
3516 log_file, strerror(errno));
3517 } else if (update && commit_ref(lock)) {
3518 status |= error("couldn't set %s", lock->ref_name);
3519 }
3520 }
3521 free(log_file);
3522 unlock_ref(lock);
3523 return status;
3524
3525 failure:
3526 rollback_lock_file(&reflog_lock);
3527 free(log_file);
3528 unlock_ref(lock);
3529 return -1;
3530}