lock_ref_for_update(): new function
[git/git.git] / refs / files-backend.c
CommitLineData
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1#include "../cache.h"
2#include "../refs.h"
3#include "refs-internal.h"
4#include "../lockfile.h"
5#include "../object.h"
6#include "../dir.h"
7
8struct ref_lock {
9 char *ref_name;
10 char *orig_ref_name;
11 struct lock_file *lk;
12 struct object_id old_oid;
13};
14
15struct ref_entry;
16
17/*
18 * Information used (along with the information in ref_entry) to
19 * describe a single cached reference. This data structure only
20 * occurs embedded in a union in struct ref_entry, and only when
21 * (ref_entry->flag & REF_DIR) is zero.
22 */
23struct ref_value {
24 /*
25 * The name of the object to which this reference resolves
26 * (which may be a tag object). If REF_ISBROKEN, this is
27 * null. If REF_ISSYMREF, then this is the name of the object
28 * referred to by the last reference in the symlink chain.
29 */
30 struct object_id oid;
31
32 /*
33 * If REF_KNOWS_PEELED, then this field holds the peeled value
34 * of this reference, or null if the reference is known not to
35 * be peelable. See the documentation for peel_ref() for an
36 * exact definition of "peelable".
37 */
38 struct object_id peeled;
39};
40
41struct ref_cache;
42
43/*
44 * Information used (along with the information in ref_entry) to
45 * describe a level in the hierarchy of references. This data
46 * structure only occurs embedded in a union in struct ref_entry, and
47 * only when (ref_entry.flag & REF_DIR) is set. In that case,
48 * (ref_entry.flag & REF_INCOMPLETE) determines whether the references
49 * in the directory have already been read:
50 *
51 * (ref_entry.flag & REF_INCOMPLETE) unset -- a directory of loose
52 * or packed references, already read.
53 *
54 * (ref_entry.flag & REF_INCOMPLETE) set -- a directory of loose
55 * references that hasn't been read yet (nor has any of its
56 * subdirectories).
57 *
58 * Entries within a directory are stored within a growable array of
59 * pointers to ref_entries (entries, nr, alloc). Entries 0 <= i <
60 * sorted are sorted by their component name in strcmp() order and the
61 * remaining entries are unsorted.
62 *
63 * Loose references are read lazily, one directory at a time. When a
64 * directory of loose references is read, then all of the references
65 * in that directory are stored, and REF_INCOMPLETE stubs are created
66 * for any subdirectories, but the subdirectories themselves are not
67 * read. The reading is triggered by get_ref_dir().
68 */
69struct ref_dir {
70 int nr, alloc;
71
72 /*
73 * Entries with index 0 <= i < sorted are sorted by name. New
74 * entries are appended to the list unsorted, and are sorted
75 * only when required; thus we avoid the need to sort the list
76 * after the addition of every reference.
77 */
78 int sorted;
79
80 /* A pointer to the ref_cache that contains this ref_dir. */
81 struct ref_cache *ref_cache;
82
83 struct ref_entry **entries;
84};
85
86/*
87 * Bit values for ref_entry::flag. REF_ISSYMREF=0x01,
88 * REF_ISPACKED=0x02, REF_ISBROKEN=0x04 and REF_BAD_NAME=0x08 are
89 * public values; see refs.h.
90 */
91
92/*
93 * The field ref_entry->u.value.peeled of this value entry contains
94 * the correct peeled value for the reference, which might be
95 * null_sha1 if the reference is not a tag or if it is broken.
96 */
97#define REF_KNOWS_PEELED 0x10
98
99/* ref_entry represents a directory of references */
100#define REF_DIR 0x20
101
102/*
103 * Entry has not yet been read from disk (used only for REF_DIR
104 * entries representing loose references)
105 */
106#define REF_INCOMPLETE 0x40
107
108/*
109 * A ref_entry represents either a reference or a "subdirectory" of
110 * references.
111 *
112 * Each directory in the reference namespace is represented by a
113 * ref_entry with (flags & REF_DIR) set and containing a subdir member
114 * that holds the entries in that directory that have been read so
115 * far. If (flags & REF_INCOMPLETE) is set, then the directory and
116 * its subdirectories haven't been read yet. REF_INCOMPLETE is only
117 * used for loose reference directories.
118 *
119 * References are represented by a ref_entry with (flags & REF_DIR)
120 * unset and a value member that describes the reference's value. The
121 * flag member is at the ref_entry level, but it is also needed to
122 * interpret the contents of the value field (in other words, a
123 * ref_value object is not very much use without the enclosing
124 * ref_entry).
125 *
126 * Reference names cannot end with slash and directories' names are
127 * always stored with a trailing slash (except for the top-level
128 * directory, which is always denoted by ""). This has two nice
129 * consequences: (1) when the entries in each subdir are sorted
130 * lexicographically by name (as they usually are), the references in
131 * a whole tree can be generated in lexicographic order by traversing
132 * the tree in left-to-right, depth-first order; (2) the names of
133 * references and subdirectories cannot conflict, and therefore the
134 * presence of an empty subdirectory does not block the creation of a
135 * similarly-named reference. (The fact that reference names with the
136 * same leading components can conflict *with each other* is a
137 * separate issue that is regulated by verify_refname_available().)
138 *
139 * Please note that the name field contains the fully-qualified
140 * reference (or subdirectory) name. Space could be saved by only
141 * storing the relative names. But that would require the full names
142 * to be generated on the fly when iterating in do_for_each_ref(), and
143 * would break callback functions, who have always been able to assume
144 * that the name strings that they are passed will not be freed during
145 * the iteration.
146 */
147struct ref_entry {
148 unsigned char flag; /* ISSYMREF? ISPACKED? */
149 union {
150 struct ref_value value; /* if not (flags&REF_DIR) */
151 struct ref_dir subdir; /* if (flags&REF_DIR) */
152 } u;
153 /*
154 * The full name of the reference (e.g., "refs/heads/master")
155 * or the full name of the directory with a trailing slash
156 * (e.g., "refs/heads/"):
157 */
158 char name[FLEX_ARRAY];
159};
160
161static void read_loose_refs(const char *dirname, struct ref_dir *dir);
162static int search_ref_dir(struct ref_dir *dir, const char *refname, size_t len);
163static struct ref_entry *create_dir_entry(struct ref_cache *ref_cache,
164 const char *dirname, size_t len,
165 int incomplete);
166static void add_entry_to_dir(struct ref_dir *dir, struct ref_entry *entry);
167
168static struct ref_dir *get_ref_dir(struct ref_entry *entry)
169{
170 struct ref_dir *dir;
171 assert(entry->flag & REF_DIR);
172 dir = &entry->u.subdir;
173 if (entry->flag & REF_INCOMPLETE) {
174 read_loose_refs(entry->name, dir);
175
176 /*
177 * Manually add refs/bisect, which, being
178 * per-worktree, might not appear in the directory
179 * listing for refs/ in the main repo.
180 */
181 if (!strcmp(entry->name, "refs/")) {
182 int pos = search_ref_dir(dir, "refs/bisect/", 12);
183 if (pos < 0) {
184 struct ref_entry *child_entry;
185 child_entry = create_dir_entry(dir->ref_cache,
186 "refs/bisect/",
187 12, 1);
188 add_entry_to_dir(dir, child_entry);
189 read_loose_refs("refs/bisect",
190 &child_entry->u.subdir);
191 }
192 }
193 entry->flag &= ~REF_INCOMPLETE;
194 }
195 return dir;
196}
197
198static struct ref_entry *create_ref_entry(const char *refname,
199 const unsigned char *sha1, int flag,
200 int check_name)
201{
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202 struct ref_entry *ref;
203
204 if (check_name &&
205 check_refname_format(refname, REFNAME_ALLOW_ONELEVEL))
206 die("Reference has invalid format: '%s'", refname);
96ffc06f 207 FLEX_ALLOC_STR(ref, name, refname);
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208 hashcpy(ref->u.value.oid.hash, sha1);
209 oidclr(&ref->u.value.peeled);
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210 ref->flag = flag;
211 return ref;
212}
213
214static void clear_ref_dir(struct ref_dir *dir);
215
216static void free_ref_entry(struct ref_entry *entry)
217{
218 if (entry->flag & REF_DIR) {
219 /*
220 * Do not use get_ref_dir() here, as that might
221 * trigger the reading of loose refs.
222 */
223 clear_ref_dir(&entry->u.subdir);
224 }
225 free(entry);
226}
227
228/*
229 * Add a ref_entry to the end of dir (unsorted). Entry is always
230 * stored directly in dir; no recursion into subdirectories is
231 * done.
232 */
233static void add_entry_to_dir(struct ref_dir *dir, struct ref_entry *entry)
234{
235 ALLOC_GROW(dir->entries, dir->nr + 1, dir->alloc);
236 dir->entries[dir->nr++] = entry;
237 /* optimize for the case that entries are added in order */
238 if (dir->nr == 1 ||
239 (dir->nr == dir->sorted + 1 &&
240 strcmp(dir->entries[dir->nr - 2]->name,
241 dir->entries[dir->nr - 1]->name) < 0))
242 dir->sorted = dir->nr;
243}
244
245/*
246 * Clear and free all entries in dir, recursively.
247 */
248static void clear_ref_dir(struct ref_dir *dir)
249{
250 int i;
251 for (i = 0; i < dir->nr; i++)
252 free_ref_entry(dir->entries[i]);
253 free(dir->entries);
254 dir->sorted = dir->nr = dir->alloc = 0;
255 dir->entries = NULL;
256}
257
258/*
259 * Create a struct ref_entry object for the specified dirname.
260 * dirname is the name of the directory with a trailing slash (e.g.,
261 * "refs/heads/") or "" for the top-level directory.
262 */
263static struct ref_entry *create_dir_entry(struct ref_cache *ref_cache,
264 const char *dirname, size_t len,
265 int incomplete)
266{
267 struct ref_entry *direntry;
96ffc06f 268 FLEX_ALLOC_MEM(direntry, name, dirname, len);
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269 direntry->u.subdir.ref_cache = ref_cache;
270 direntry->flag = REF_DIR | (incomplete ? REF_INCOMPLETE : 0);
271 return direntry;
272}
273
274static int ref_entry_cmp(const void *a, const void *b)
275{
276 struct ref_entry *one = *(struct ref_entry **)a;
277 struct ref_entry *two = *(struct ref_entry **)b;
278 return strcmp(one->name, two->name);
279}
280
281static void sort_ref_dir(struct ref_dir *dir);
282
283struct string_slice {
284 size_t len;
285 const char *str;
286};
287
288static int ref_entry_cmp_sslice(const void *key_, const void *ent_)
289{
290 const struct string_slice *key = key_;
291 const struct ref_entry *ent = *(const struct ref_entry * const *)ent_;
292 int cmp = strncmp(key->str, ent->name, key->len);
293 if (cmp)
294 return cmp;
295 return '\0' - (unsigned char)ent->name[key->len];
296}
297
298/*
299 * Return the index of the entry with the given refname from the
300 * ref_dir (non-recursively), sorting dir if necessary. Return -1 if
301 * no such entry is found. dir must already be complete.
302 */
303static int search_ref_dir(struct ref_dir *dir, const char *refname, size_t len)
304{
305 struct ref_entry **r;
306 struct string_slice key;
307
308 if (refname == NULL || !dir->nr)
309 return -1;
310
311 sort_ref_dir(dir);
312 key.len = len;
313 key.str = refname;
314 r = bsearch(&key, dir->entries, dir->nr, sizeof(*dir->entries),
315 ref_entry_cmp_sslice);
316
317 if (r == NULL)
318 return -1;
319
320 return r - dir->entries;
321}
322
323/*
324 * Search for a directory entry directly within dir (without
325 * recursing). Sort dir if necessary. subdirname must be a directory
326 * name (i.e., end in '/'). If mkdir is set, then create the
327 * directory if it is missing; otherwise, return NULL if the desired
328 * directory cannot be found. dir must already be complete.
329 */
330static struct ref_dir *search_for_subdir(struct ref_dir *dir,
331 const char *subdirname, size_t len,
332 int mkdir)
333{
334 int entry_index = search_ref_dir(dir, subdirname, len);
335 struct ref_entry *entry;
336 if (entry_index == -1) {
337 if (!mkdir)
338 return NULL;
339 /*
340 * Since dir is complete, the absence of a subdir
341 * means that the subdir really doesn't exist;
342 * therefore, create an empty record for it but mark
343 * the record complete.
344 */
345 entry = create_dir_entry(dir->ref_cache, subdirname, len, 0);
346 add_entry_to_dir(dir, entry);
347 } else {
348 entry = dir->entries[entry_index];
349 }
350 return get_ref_dir(entry);
351}
352
353/*
354 * If refname is a reference name, find the ref_dir within the dir
355 * tree that should hold refname. If refname is a directory name
356 * (i.e., ends in '/'), then return that ref_dir itself. dir must
357 * represent the top-level directory and must already be complete.
358 * Sort ref_dirs and recurse into subdirectories as necessary. If
359 * mkdir is set, then create any missing directories; otherwise,
360 * return NULL if the desired directory cannot be found.
361 */
362static struct ref_dir *find_containing_dir(struct ref_dir *dir,
363 const char *refname, int mkdir)
364{
365 const char *slash;
366 for (slash = strchr(refname, '/'); slash; slash = strchr(slash + 1, '/')) {
367 size_t dirnamelen = slash - refname + 1;
368 struct ref_dir *subdir;
369 subdir = search_for_subdir(dir, refname, dirnamelen, mkdir);
370 if (!subdir) {
371 dir = NULL;
372 break;
373 }
374 dir = subdir;
375 }
376
377 return dir;
378}
379
380/*
381 * Find the value entry with the given name in dir, sorting ref_dirs
382 * and recursing into subdirectories as necessary. If the name is not
383 * found or it corresponds to a directory entry, return NULL.
384 */
385static struct ref_entry *find_ref(struct ref_dir *dir, const char *refname)
386{
387 int entry_index;
388 struct ref_entry *entry;
389 dir = find_containing_dir(dir, refname, 0);
390 if (!dir)
391 return NULL;
392 entry_index = search_ref_dir(dir, refname, strlen(refname));
393 if (entry_index == -1)
394 return NULL;
395 entry = dir->entries[entry_index];
396 return (entry->flag & REF_DIR) ? NULL : entry;
397}
398
399/*
400 * Remove the entry with the given name from dir, recursing into
401 * subdirectories as necessary. If refname is the name of a directory
402 * (i.e., ends with '/'), then remove the directory and its contents.
403 * If the removal was successful, return the number of entries
404 * remaining in the directory entry that contained the deleted entry.
405 * If the name was not found, return -1. Please note that this
406 * function only deletes the entry from the cache; it does not delete
407 * it from the filesystem or ensure that other cache entries (which
408 * might be symbolic references to the removed entry) are updated.
409 * Nor does it remove any containing dir entries that might be made
410 * empty by the removal. dir must represent the top-level directory
411 * and must already be complete.
412 */
413static int remove_entry(struct ref_dir *dir, const char *refname)
414{
415 int refname_len = strlen(refname);
416 int entry_index;
417 struct ref_entry *entry;
418 int is_dir = refname[refname_len - 1] == '/';
419 if (is_dir) {
420 /*
421 * refname represents a reference directory. Remove
422 * the trailing slash; otherwise we will get the
423 * directory *representing* refname rather than the
424 * one *containing* it.
425 */
426 char *dirname = xmemdupz(refname, refname_len - 1);
427 dir = find_containing_dir(dir, dirname, 0);
428 free(dirname);
429 } else {
430 dir = find_containing_dir(dir, refname, 0);
431 }
432 if (!dir)
433 return -1;
434 entry_index = search_ref_dir(dir, refname, refname_len);
435 if (entry_index == -1)
436 return -1;
437 entry = dir->entries[entry_index];
438
439 memmove(&dir->entries[entry_index],
440 &dir->entries[entry_index + 1],
441 (dir->nr - entry_index - 1) * sizeof(*dir->entries)
442 );
443 dir->nr--;
444 if (dir->sorted > entry_index)
445 dir->sorted--;
446 free_ref_entry(entry);
447 return dir->nr;
448}
449
450/*
451 * Add a ref_entry to the ref_dir (unsorted), recursing into
452 * subdirectories as necessary. dir must represent the top-level
453 * directory. Return 0 on success.
454 */
455static int add_ref(struct ref_dir *dir, struct ref_entry *ref)
456{
457 dir = find_containing_dir(dir, ref->name, 1);
458 if (!dir)
459 return -1;
460 add_entry_to_dir(dir, ref);
461 return 0;
462}
463
464/*
465 * Emit a warning and return true iff ref1 and ref2 have the same name
466 * and the same sha1. Die if they have the same name but different
467 * sha1s.
468 */
469static int is_dup_ref(const struct ref_entry *ref1, const struct ref_entry *ref2)
470{
471 if (strcmp(ref1->name, ref2->name))
472 return 0;
473
474 /* Duplicate name; make sure that they don't conflict: */
475
476 if ((ref1->flag & REF_DIR) || (ref2->flag & REF_DIR))
477 /* This is impossible by construction */
478 die("Reference directory conflict: %s", ref1->name);
479
480 if (oidcmp(&ref1->u.value.oid, &ref2->u.value.oid))
481 die("Duplicated ref, and SHA1s don't match: %s", ref1->name);
482
483 warning("Duplicated ref: %s", ref1->name);
484 return 1;
485}
486
487/*
488 * Sort the entries in dir non-recursively (if they are not already
489 * sorted) and remove any duplicate entries.
490 */
491static void sort_ref_dir(struct ref_dir *dir)
492{
493 int i, j;
494 struct ref_entry *last = NULL;
495
496 /*
497 * This check also prevents passing a zero-length array to qsort(),
498 * which is a problem on some platforms.
499 */
500 if (dir->sorted == dir->nr)
501 return;
502
503 qsort(dir->entries, dir->nr, sizeof(*dir->entries), ref_entry_cmp);
504
505 /* Remove any duplicates: */
506 for (i = 0, j = 0; j < dir->nr; j++) {
507 struct ref_entry *entry = dir->entries[j];
508 if (last && is_dup_ref(last, entry))
509 free_ref_entry(entry);
510 else
511 last = dir->entries[i++] = entry;
512 }
513 dir->sorted = dir->nr = i;
514}
515
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516/*
517 * Return true iff the reference described by entry can be resolved to
518 * an object in the database. Emit a warning if the referred-to
519 * object does not exist.
520 */
521static int ref_resolves_to_object(struct ref_entry *entry)
522{
523 if (entry->flag & REF_ISBROKEN)
524 return 0;
525 if (!has_sha1_file(entry->u.value.oid.hash)) {
526 error("%s does not point to a valid object!", entry->name);
527 return 0;
528 }
529 return 1;
530}
531
532/*
533 * current_ref is a performance hack: when iterating over references
534 * using the for_each_ref*() functions, current_ref is set to the
535 * current reference's entry before calling the callback function. If
536 * the callback function calls peel_ref(), then peel_ref() first
537 * checks whether the reference to be peeled is the current reference
538 * (it usually is) and if so, returns that reference's peeled version
539 * if it is available. This avoids a refname lookup in a common case.
540 */
541static struct ref_entry *current_ref;
542
543typedef int each_ref_entry_fn(struct ref_entry *entry, void *cb_data);
544
545struct ref_entry_cb {
546 const char *base;
547 int trim;
548 int flags;
549 each_ref_fn *fn;
550 void *cb_data;
551};
552
553/*
554 * Handle one reference in a do_for_each_ref*()-style iteration,
555 * calling an each_ref_fn for each entry.
556 */
557static int do_one_ref(struct ref_entry *entry, void *cb_data)
558{
559 struct ref_entry_cb *data = cb_data;
560 struct ref_entry *old_current_ref;
561 int retval;
562
563 if (!starts_with(entry->name, data->base))
564 return 0;
565
566 if (!(data->flags & DO_FOR_EACH_INCLUDE_BROKEN) &&
567 !ref_resolves_to_object(entry))
568 return 0;
569
570 /* Store the old value, in case this is a recursive call: */
571 old_current_ref = current_ref;
572 current_ref = entry;
573 retval = data->fn(entry->name + data->trim, &entry->u.value.oid,
574 entry->flag, data->cb_data);
575 current_ref = old_current_ref;
576 return retval;
577}
578
579/*
580 * Call fn for each reference in dir that has index in the range
581 * offset <= index < dir->nr. Recurse into subdirectories that are in
582 * that index range, sorting them before iterating. This function
583 * does not sort dir itself; it should be sorted beforehand. fn is
584 * called for all references, including broken ones.
585 */
586static int do_for_each_entry_in_dir(struct ref_dir *dir, int offset,
587 each_ref_entry_fn fn, void *cb_data)
588{
589 int i;
590 assert(dir->sorted == dir->nr);
591 for (i = offset; i < dir->nr; i++) {
592 struct ref_entry *entry = dir->entries[i];
593 int retval;
594 if (entry->flag & REF_DIR) {
595 struct ref_dir *subdir = get_ref_dir(entry);
596 sort_ref_dir(subdir);
597 retval = do_for_each_entry_in_dir(subdir, 0, fn, cb_data);
598 } else {
599 retval = fn(entry, cb_data);
600 }
601 if (retval)
602 return retval;
603 }
604 return 0;
605}
606
607/*
608 * Call fn for each reference in the union of dir1 and dir2, in order
609 * by refname. Recurse into subdirectories. If a value entry appears
610 * in both dir1 and dir2, then only process the version that is in
611 * dir2. The input dirs must already be sorted, but subdirs will be
612 * sorted as needed. fn is called for all references, including
613 * broken ones.
614 */
615static int do_for_each_entry_in_dirs(struct ref_dir *dir1,
616 struct ref_dir *dir2,
617 each_ref_entry_fn fn, void *cb_data)
618{
619 int retval;
620 int i1 = 0, i2 = 0;
621
622 assert(dir1->sorted == dir1->nr);
623 assert(dir2->sorted == dir2->nr);
624 while (1) {
625 struct ref_entry *e1, *e2;
626 int cmp;
627 if (i1 == dir1->nr) {
628 return do_for_each_entry_in_dir(dir2, i2, fn, cb_data);
629 }
630 if (i2 == dir2->nr) {
631 return do_for_each_entry_in_dir(dir1, i1, fn, cb_data);
632 }
633 e1 = dir1->entries[i1];
634 e2 = dir2->entries[i2];
635 cmp = strcmp(e1->name, e2->name);
636 if (cmp == 0) {
637 if ((e1->flag & REF_DIR) && (e2->flag & REF_DIR)) {
638 /* Both are directories; descend them in parallel. */
639 struct ref_dir *subdir1 = get_ref_dir(e1);
640 struct ref_dir *subdir2 = get_ref_dir(e2);
641 sort_ref_dir(subdir1);
642 sort_ref_dir(subdir2);
643 retval = do_for_each_entry_in_dirs(
644 subdir1, subdir2, fn, cb_data);
645 i1++;
646 i2++;
647 } else if (!(e1->flag & REF_DIR) && !(e2->flag & REF_DIR)) {
648 /* Both are references; ignore the one from dir1. */
649 retval = fn(e2, cb_data);
650 i1++;
651 i2++;
652 } else {
653 die("conflict between reference and directory: %s",
654 e1->name);
655 }
656 } else {
657 struct ref_entry *e;
658 if (cmp < 0) {
659 e = e1;
660 i1++;
661 } else {
662 e = e2;
663 i2++;
664 }
665 if (e->flag & REF_DIR) {
666 struct ref_dir *subdir = get_ref_dir(e);
667 sort_ref_dir(subdir);
668 retval = do_for_each_entry_in_dir(
669 subdir, 0, fn, cb_data);
670 } else {
671 retval = fn(e, cb_data);
672 }
673 }
674 if (retval)
675 return retval;
676 }
677}
678
679/*
680 * Load all of the refs from the dir into our in-memory cache. The hard work
681 * of loading loose refs is done by get_ref_dir(), so we just need to recurse
682 * through all of the sub-directories. We do not even need to care about
683 * sorting, as traversal order does not matter to us.
684 */
685static void prime_ref_dir(struct ref_dir *dir)
686{
687 int i;
688 for (i = 0; i < dir->nr; i++) {
689 struct ref_entry *entry = dir->entries[i];
690 if (entry->flag & REF_DIR)
691 prime_ref_dir(get_ref_dir(entry));
692 }
693}
694
695struct nonmatching_ref_data {
696 const struct string_list *skip;
697 const char *conflicting_refname;
698};
699
700static int nonmatching_ref_fn(struct ref_entry *entry, void *vdata)
701{
702 struct nonmatching_ref_data *data = vdata;
703
704 if (data->skip && string_list_has_string(data->skip, entry->name))
705 return 0;
706
707 data->conflicting_refname = entry->name;
708 return 1;
709}
710
711/*
712 * Return 0 if a reference named refname could be created without
713 * conflicting with the name of an existing reference in dir.
714 * See verify_refname_available for more information.
715 */
716static int verify_refname_available_dir(const char *refname,
717 const struct string_list *extras,
718 const struct string_list *skip,
719 struct ref_dir *dir,
720 struct strbuf *err)
721{
722 const char *slash;
0845122c 723 const char *extra_refname;
7bd9bcf3
MH
724 int pos;
725 struct strbuf dirname = STRBUF_INIT;
726 int ret = -1;
727
728 /*
729 * For the sake of comments in this function, suppose that
730 * refname is "refs/foo/bar".
731 */
732
733 assert(err);
734
735 strbuf_grow(&dirname, strlen(refname) + 1);
736 for (slash = strchr(refname, '/'); slash; slash = strchr(slash + 1, '/')) {
737 /* Expand dirname to the new prefix, not including the trailing slash: */
738 strbuf_add(&dirname, refname + dirname.len, slash - refname - dirname.len);
739
740 /*
741 * We are still at a leading dir of the refname (e.g.,
742 * "refs/foo"; if there is a reference with that name,
743 * it is a conflict, *unless* it is in skip.
744 */
745 if (dir) {
746 pos = search_ref_dir(dir, dirname.buf, dirname.len);
747 if (pos >= 0 &&
748 (!skip || !string_list_has_string(skip, dirname.buf))) {
749 /*
750 * We found a reference whose name is
751 * a proper prefix of refname; e.g.,
752 * "refs/foo", and is not in skip.
753 */
754 strbuf_addf(err, "'%s' exists; cannot create '%s'",
755 dirname.buf, refname);
756 goto cleanup;
757 }
758 }
759
760 if (extras && string_list_has_string(extras, dirname.buf) &&
761 (!skip || !string_list_has_string(skip, dirname.buf))) {
762 strbuf_addf(err, "cannot process '%s' and '%s' at the same time",
763 refname, dirname.buf);
764 goto cleanup;
765 }
766
767 /*
768 * Otherwise, we can try to continue our search with
769 * the next component. So try to look up the
770 * directory, e.g., "refs/foo/". If we come up empty,
771 * we know there is nothing under this whole prefix,
772 * but even in that case we still have to continue the
773 * search for conflicts with extras.
774 */
775 strbuf_addch(&dirname, '/');
776 if (dir) {
777 pos = search_ref_dir(dir, dirname.buf, dirname.len);
778 if (pos < 0) {
779 /*
780 * There was no directory "refs/foo/",
781 * so there is nothing under this
782 * whole prefix. So there is no need
783 * to continue looking for conflicting
784 * references. But we need to continue
785 * looking for conflicting extras.
786 */
787 dir = NULL;
788 } else {
789 dir = get_ref_dir(dir->entries[pos]);
790 }
791 }
792 }
793
794 /*
795 * We are at the leaf of our refname (e.g., "refs/foo/bar").
796 * There is no point in searching for a reference with that
797 * name, because a refname isn't considered to conflict with
798 * itself. But we still need to check for references whose
799 * names are in the "refs/foo/bar/" namespace, because they
800 * *do* conflict.
801 */
802 strbuf_addstr(&dirname, refname + dirname.len);
803 strbuf_addch(&dirname, '/');
804
805 if (dir) {
806 pos = search_ref_dir(dir, dirname.buf, dirname.len);
807
808 if (pos >= 0) {
809 /*
810 * We found a directory named "$refname/"
811 * (e.g., "refs/foo/bar/"). It is a problem
812 * iff it contains any ref that is not in
813 * "skip".
814 */
815 struct nonmatching_ref_data data;
816
817 data.skip = skip;
818 data.conflicting_refname = NULL;
819 dir = get_ref_dir(dir->entries[pos]);
820 sort_ref_dir(dir);
821 if (do_for_each_entry_in_dir(dir, 0, nonmatching_ref_fn, &data)) {
822 strbuf_addf(err, "'%s' exists; cannot create '%s'",
823 data.conflicting_refname, refname);
824 goto cleanup;
825 }
826 }
827 }
828
0845122c
DT
829 extra_refname = find_descendant_ref(dirname.buf, extras, skip);
830 if (extra_refname)
831 strbuf_addf(err, "cannot process '%s' and '%s' at the same time",
832 refname, extra_refname);
833 else
834 ret = 0;
7bd9bcf3
MH
835
836cleanup:
837 strbuf_release(&dirname);
838 return ret;
839}
840
841struct packed_ref_cache {
842 struct ref_entry *root;
843
844 /*
845 * Count of references to the data structure in this instance,
846 * including the pointer from ref_cache::packed if any. The
847 * data will not be freed as long as the reference count is
848 * nonzero.
849 */
850 unsigned int referrers;
851
852 /*
853 * Iff the packed-refs file associated with this instance is
854 * currently locked for writing, this points at the associated
855 * lock (which is owned by somebody else). The referrer count
856 * is also incremented when the file is locked and decremented
857 * when it is unlocked.
858 */
859 struct lock_file *lock;
860
861 /* The metadata from when this packed-refs cache was read */
862 struct stat_validity validity;
863};
864
865/*
866 * Future: need to be in "struct repository"
867 * when doing a full libification.
868 */
869static struct ref_cache {
870 struct ref_cache *next;
871 struct ref_entry *loose;
872 struct packed_ref_cache *packed;
873 /*
874 * The submodule name, or "" for the main repo. We allocate
875 * length 1 rather than FLEX_ARRAY so that the main ref_cache
876 * is initialized correctly.
877 */
878 char name[1];
879} ref_cache, *submodule_ref_caches;
880
881/* Lock used for the main packed-refs file: */
882static struct lock_file packlock;
883
884/*
885 * Increment the reference count of *packed_refs.
886 */
887static void acquire_packed_ref_cache(struct packed_ref_cache *packed_refs)
888{
889 packed_refs->referrers++;
890}
891
892/*
893 * Decrease the reference count of *packed_refs. If it goes to zero,
894 * free *packed_refs and return true; otherwise return false.
895 */
896static int release_packed_ref_cache(struct packed_ref_cache *packed_refs)
897{
898 if (!--packed_refs->referrers) {
899 free_ref_entry(packed_refs->root);
900 stat_validity_clear(&packed_refs->validity);
901 free(packed_refs);
902 return 1;
903 } else {
904 return 0;
905 }
906}
907
908static void clear_packed_ref_cache(struct ref_cache *refs)
909{
910 if (refs->packed) {
911 struct packed_ref_cache *packed_refs = refs->packed;
912
913 if (packed_refs->lock)
914 die("internal error: packed-ref cache cleared while locked");
915 refs->packed = NULL;
916 release_packed_ref_cache(packed_refs);
917 }
918}
919
920static void clear_loose_ref_cache(struct ref_cache *refs)
921{
922 if (refs->loose) {
923 free_ref_entry(refs->loose);
924 refs->loose = NULL;
925 }
926}
927
a2d5156c
JK
928/*
929 * Create a new submodule ref cache and add it to the internal
930 * set of caches.
931 */
7bd9bcf3
MH
932static struct ref_cache *create_ref_cache(const char *submodule)
933{
7bd9bcf3
MH
934 struct ref_cache *refs;
935 if (!submodule)
936 submodule = "";
96ffc06f 937 FLEX_ALLOC_STR(refs, name, submodule);
a2d5156c
JK
938 refs->next = submodule_ref_caches;
939 submodule_ref_caches = refs;
7bd9bcf3
MH
940 return refs;
941}
942
a2d5156c 943static struct ref_cache *lookup_ref_cache(const char *submodule)
7bd9bcf3
MH
944{
945 struct ref_cache *refs;
946
947 if (!submodule || !*submodule)
948 return &ref_cache;
949
950 for (refs = submodule_ref_caches; refs; refs = refs->next)
951 if (!strcmp(submodule, refs->name))
952 return refs;
a2d5156c
JK
953 return NULL;
954}
7bd9bcf3 955
a2d5156c
JK
956/*
957 * Return a pointer to a ref_cache for the specified submodule. For
958 * the main repository, use submodule==NULL. The returned structure
959 * will be allocated and initialized but not necessarily populated; it
960 * should not be freed.
961 */
962static struct ref_cache *get_ref_cache(const char *submodule)
963{
964 struct ref_cache *refs = lookup_ref_cache(submodule);
965 if (!refs)
966 refs = create_ref_cache(submodule);
7bd9bcf3
MH
967 return refs;
968}
969
970/* The length of a peeled reference line in packed-refs, including EOL: */
971#define PEELED_LINE_LENGTH 42
972
973/*
974 * The packed-refs header line that we write out. Perhaps other
975 * traits will be added later. The trailing space is required.
976 */
977static const char PACKED_REFS_HEADER[] =
978 "# pack-refs with: peeled fully-peeled \n";
979
980/*
981 * Parse one line from a packed-refs file. Write the SHA1 to sha1.
982 * Return a pointer to the refname within the line (null-terminated),
983 * or NULL if there was a problem.
984 */
985static const char *parse_ref_line(struct strbuf *line, unsigned char *sha1)
986{
987 const char *ref;
988
989 /*
990 * 42: the answer to everything.
991 *
992 * In this case, it happens to be the answer to
993 * 40 (length of sha1 hex representation)
994 * +1 (space in between hex and name)
995 * +1 (newline at the end of the line)
996 */
997 if (line->len <= 42)
998 return NULL;
999
1000 if (get_sha1_hex(line->buf, sha1) < 0)
1001 return NULL;
1002 if (!isspace(line->buf[40]))
1003 return NULL;
1004
1005 ref = line->buf + 41;
1006 if (isspace(*ref))
1007 return NULL;
1008
1009 if (line->buf[line->len - 1] != '\n')
1010 return NULL;
1011 line->buf[--line->len] = 0;
1012
1013 return ref;
1014}
1015
1016/*
1017 * Read f, which is a packed-refs file, into dir.
1018 *
1019 * A comment line of the form "# pack-refs with: " may contain zero or
1020 * more traits. We interpret the traits as follows:
1021 *
1022 * No traits:
1023 *
1024 * Probably no references are peeled. But if the file contains a
1025 * peeled value for a reference, we will use it.
1026 *
1027 * peeled:
1028 *
1029 * References under "refs/tags/", if they *can* be peeled, *are*
1030 * peeled in this file. References outside of "refs/tags/" are
1031 * probably not peeled even if they could have been, but if we find
1032 * a peeled value for such a reference we will use it.
1033 *
1034 * fully-peeled:
1035 *
1036 * All references in the file that can be peeled are peeled.
1037 * Inversely (and this is more important), any references in the
1038 * file for which no peeled value is recorded is not peelable. This
1039 * trait should typically be written alongside "peeled" for
1040 * compatibility with older clients, but we do not require it
1041 * (i.e., "peeled" is a no-op if "fully-peeled" is set).
1042 */
1043static void read_packed_refs(FILE *f, struct ref_dir *dir)
1044{
1045 struct ref_entry *last = NULL;
1046 struct strbuf line = STRBUF_INIT;
1047 enum { PEELED_NONE, PEELED_TAGS, PEELED_FULLY } peeled = PEELED_NONE;
1048
1049 while (strbuf_getwholeline(&line, f, '\n') != EOF) {
1050 unsigned char sha1[20];
1051 const char *refname;
1052 const char *traits;
1053
1054 if (skip_prefix(line.buf, "# pack-refs with:", &traits)) {
1055 if (strstr(traits, " fully-peeled "))
1056 peeled = PEELED_FULLY;
1057 else if (strstr(traits, " peeled "))
1058 peeled = PEELED_TAGS;
1059 /* perhaps other traits later as well */
1060 continue;
1061 }
1062
1063 refname = parse_ref_line(&line, sha1);
1064 if (refname) {
1065 int flag = REF_ISPACKED;
1066
1067 if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
1068 if (!refname_is_safe(refname))
1069 die("packed refname is dangerous: %s", refname);
1070 hashclr(sha1);
1071 flag |= REF_BAD_NAME | REF_ISBROKEN;
1072 }
1073 last = create_ref_entry(refname, sha1, flag, 0);
1074 if (peeled == PEELED_FULLY ||
1075 (peeled == PEELED_TAGS && starts_with(refname, "refs/tags/")))
1076 last->flag |= REF_KNOWS_PEELED;
1077 add_ref(dir, last);
1078 continue;
1079 }
1080 if (last &&
1081 line.buf[0] == '^' &&
1082 line.len == PEELED_LINE_LENGTH &&
1083 line.buf[PEELED_LINE_LENGTH - 1] == '\n' &&
1084 !get_sha1_hex(line.buf + 1, sha1)) {
1085 hashcpy(last->u.value.peeled.hash, sha1);
1086 /*
1087 * Regardless of what the file header said,
1088 * we definitely know the value of *this*
1089 * reference:
1090 */
1091 last->flag |= REF_KNOWS_PEELED;
1092 }
1093 }
1094
1095 strbuf_release(&line);
1096}
1097
1098/*
1099 * Get the packed_ref_cache for the specified ref_cache, creating it
1100 * if necessary.
1101 */
1102static struct packed_ref_cache *get_packed_ref_cache(struct ref_cache *refs)
1103{
1104 char *packed_refs_file;
1105
1106 if (*refs->name)
1107 packed_refs_file = git_pathdup_submodule(refs->name, "packed-refs");
1108 else
1109 packed_refs_file = git_pathdup("packed-refs");
1110
1111 if (refs->packed &&
1112 !stat_validity_check(&refs->packed->validity, packed_refs_file))
1113 clear_packed_ref_cache(refs);
1114
1115 if (!refs->packed) {
1116 FILE *f;
1117
1118 refs->packed = xcalloc(1, sizeof(*refs->packed));
1119 acquire_packed_ref_cache(refs->packed);
1120 refs->packed->root = create_dir_entry(refs, "", 0, 0);
1121 f = fopen(packed_refs_file, "r");
1122 if (f) {
1123 stat_validity_update(&refs->packed->validity, fileno(f));
1124 read_packed_refs(f, get_ref_dir(refs->packed->root));
1125 fclose(f);
1126 }
1127 }
1128 free(packed_refs_file);
1129 return refs->packed;
1130}
1131
1132static struct ref_dir *get_packed_ref_dir(struct packed_ref_cache *packed_ref_cache)
1133{
1134 return get_ref_dir(packed_ref_cache->root);
1135}
1136
1137static struct ref_dir *get_packed_refs(struct ref_cache *refs)
1138{
1139 return get_packed_ref_dir(get_packed_ref_cache(refs));
1140}
1141
1142/*
1143 * Add a reference to the in-memory packed reference cache. This may
1144 * only be called while the packed-refs file is locked (see
1145 * lock_packed_refs()). To actually write the packed-refs file, call
1146 * commit_packed_refs().
1147 */
1148static void add_packed_ref(const char *refname, const unsigned char *sha1)
1149{
1150 struct packed_ref_cache *packed_ref_cache =
1151 get_packed_ref_cache(&ref_cache);
1152
1153 if (!packed_ref_cache->lock)
1154 die("internal error: packed refs not locked");
1155 add_ref(get_packed_ref_dir(packed_ref_cache),
1156 create_ref_entry(refname, sha1, REF_ISPACKED, 1));
1157}
1158
1159/*
1160 * Read the loose references from the namespace dirname into dir
1161 * (without recursing). dirname must end with '/'. dir must be the
1162 * directory entry corresponding to dirname.
1163 */
1164static void read_loose_refs(const char *dirname, struct ref_dir *dir)
1165{
1166 struct ref_cache *refs = dir->ref_cache;
1167 DIR *d;
1168 struct dirent *de;
1169 int dirnamelen = strlen(dirname);
1170 struct strbuf refname;
1171 struct strbuf path = STRBUF_INIT;
1172 size_t path_baselen;
1173
1174 if (*refs->name)
1175 strbuf_git_path_submodule(&path, refs->name, "%s", dirname);
1176 else
1177 strbuf_git_path(&path, "%s", dirname);
1178 path_baselen = path.len;
1179
1180 d = opendir(path.buf);
1181 if (!d) {
1182 strbuf_release(&path);
1183 return;
1184 }
1185
1186 strbuf_init(&refname, dirnamelen + 257);
1187 strbuf_add(&refname, dirname, dirnamelen);
1188
1189 while ((de = readdir(d)) != NULL) {
1190 unsigned char sha1[20];
1191 struct stat st;
1192 int flag;
1193
1194 if (de->d_name[0] == '.')
1195 continue;
1196 if (ends_with(de->d_name, ".lock"))
1197 continue;
1198 strbuf_addstr(&refname, de->d_name);
1199 strbuf_addstr(&path, de->d_name);
1200 if (stat(path.buf, &st) < 0) {
1201 ; /* silently ignore */
1202 } else if (S_ISDIR(st.st_mode)) {
1203 strbuf_addch(&refname, '/');
1204 add_entry_to_dir(dir,
1205 create_dir_entry(refs, refname.buf,
1206 refname.len, 1));
1207 } else {
1208 int read_ok;
1209
1210 if (*refs->name) {
1211 hashclr(sha1);
1212 flag = 0;
1213 read_ok = !resolve_gitlink_ref(refs->name,
1214 refname.buf, sha1);
1215 } else {
1216 read_ok = !read_ref_full(refname.buf,
1217 RESOLVE_REF_READING,
1218 sha1, &flag);
1219 }
1220
1221 if (!read_ok) {
1222 hashclr(sha1);
1223 flag |= REF_ISBROKEN;
1224 } else if (is_null_sha1(sha1)) {
1225 /*
1226 * It is so astronomically unlikely
1227 * that NULL_SHA1 is the SHA-1 of an
1228 * actual object that we consider its
1229 * appearance in a loose reference
1230 * file to be repo corruption
1231 * (probably due to a software bug).
1232 */
1233 flag |= REF_ISBROKEN;
1234 }
1235
1236 if (check_refname_format(refname.buf,
1237 REFNAME_ALLOW_ONELEVEL)) {
1238 if (!refname_is_safe(refname.buf))
1239 die("loose refname is dangerous: %s", refname.buf);
1240 hashclr(sha1);
1241 flag |= REF_BAD_NAME | REF_ISBROKEN;
1242 }
1243 add_entry_to_dir(dir,
1244 create_ref_entry(refname.buf, sha1, flag, 0));
1245 }
1246 strbuf_setlen(&refname, dirnamelen);
1247 strbuf_setlen(&path, path_baselen);
1248 }
1249 strbuf_release(&refname);
1250 strbuf_release(&path);
1251 closedir(d);
1252}
1253
1254static struct ref_dir *get_loose_refs(struct ref_cache *refs)
1255{
1256 if (!refs->loose) {
1257 /*
1258 * Mark the top-level directory complete because we
1259 * are about to read the only subdirectory that can
1260 * hold references:
1261 */
1262 refs->loose = create_dir_entry(refs, "", 0, 0);
1263 /*
1264 * Create an incomplete entry for "refs/":
1265 */
1266 add_entry_to_dir(get_ref_dir(refs->loose),
1267 create_dir_entry(refs, "refs/", 5, 1));
1268 }
1269 return get_ref_dir(refs->loose);
1270}
1271
7bd9bcf3
MH
1272#define MAXREFLEN (1024)
1273
1274/*
1275 * Called by resolve_gitlink_ref_recursive() after it failed to read
1276 * from the loose refs in ref_cache refs. Find <refname> in the
1277 * packed-refs file for the submodule.
1278 */
1279static int resolve_gitlink_packed_ref(struct ref_cache *refs,
1280 const char *refname, unsigned char *sha1)
1281{
1282 struct ref_entry *ref;
1283 struct ref_dir *dir = get_packed_refs(refs);
1284
1285 ref = find_ref(dir, refname);
1286 if (ref == NULL)
1287 return -1;
1288
1289 hashcpy(sha1, ref->u.value.oid.hash);
1290 return 0;
1291}
1292
1293static int resolve_gitlink_ref_recursive(struct ref_cache *refs,
1294 const char *refname, unsigned char *sha1,
1295 int recursion)
1296{
1297 int fd, len;
1298 char buffer[128], *p;
1299 char *path;
1300
2d0663b2 1301 if (recursion > SYMREF_MAXDEPTH || strlen(refname) > MAXREFLEN)
7bd9bcf3
MH
1302 return -1;
1303 path = *refs->name
1304 ? git_pathdup_submodule(refs->name, "%s", refname)
1305 : git_pathdup("%s", refname);
1306 fd = open(path, O_RDONLY);
1307 free(path);
1308 if (fd < 0)
1309 return resolve_gitlink_packed_ref(refs, refname, sha1);
1310
1311 len = read(fd, buffer, sizeof(buffer)-1);
1312 close(fd);
1313 if (len < 0)
1314 return -1;
1315 while (len && isspace(buffer[len-1]))
1316 len--;
1317 buffer[len] = 0;
1318
1319 /* Was it a detached head or an old-fashioned symlink? */
1320 if (!get_sha1_hex(buffer, sha1))
1321 return 0;
1322
1323 /* Symref? */
1324 if (strncmp(buffer, "ref:", 4))
1325 return -1;
1326 p = buffer + 4;
1327 while (isspace(*p))
1328 p++;
1329
1330 return resolve_gitlink_ref_recursive(refs, p, sha1, recursion+1);
1331}
1332
1333int resolve_gitlink_ref(const char *path, const char *refname, unsigned char *sha1)
1334{
1335 int len = strlen(path), retval;
a2d5156c 1336 struct strbuf submodule = STRBUF_INIT;
7bd9bcf3
MH
1337 struct ref_cache *refs;
1338
1339 while (len && path[len-1] == '/')
1340 len--;
1341 if (!len)
1342 return -1;
a2d5156c
JK
1343
1344 strbuf_add(&submodule, path, len);
1345 refs = lookup_ref_cache(submodule.buf);
1346 if (!refs) {
1347 if (!is_nonbare_repository_dir(&submodule)) {
1348 strbuf_release(&submodule);
1349 return -1;
1350 }
1351 refs = create_ref_cache(submodule.buf);
1352 }
1353 strbuf_release(&submodule);
7bd9bcf3
MH
1354
1355 retval = resolve_gitlink_ref_recursive(refs, refname, sha1, 0);
1356 return retval;
1357}
1358
1359/*
1360 * Return the ref_entry for the given refname from the packed
1361 * references. If it does not exist, return NULL.
1362 */
1363static struct ref_entry *get_packed_ref(const char *refname)
1364{
1365 return find_ref(get_packed_refs(&ref_cache), refname);
1366}
1367
1368/*
419c6f4c 1369 * A loose ref file doesn't exist; check for a packed ref.
7bd9bcf3
MH
1370 */
1371static int resolve_missing_loose_ref(const char *refname,
7bd9bcf3 1372 unsigned char *sha1,
89e82389 1373 unsigned int *flags)
7bd9bcf3
MH
1374{
1375 struct ref_entry *entry;
1376
1377 /*
1378 * The loose reference file does not exist; check for a packed
1379 * reference.
1380 */
1381 entry = get_packed_ref(refname);
1382 if (entry) {
1383 hashcpy(sha1, entry->u.value.oid.hash);
a70a93b7 1384 *flags |= REF_ISPACKED;
7bd9bcf3
MH
1385 return 0;
1386 }
419c6f4c
MH
1387 /* refname is not a packed reference. */
1388 return -1;
7bd9bcf3
MH
1389}
1390
2d0663b2 1391int read_raw_ref(const char *refname, unsigned char *sha1,
92b38093 1392 struct strbuf *referent, unsigned int *type)
7bd9bcf3 1393{
42a38cf7
MH
1394 struct strbuf sb_contents = STRBUF_INIT;
1395 struct strbuf sb_path = STRBUF_INIT;
7048653a
DT
1396 const char *path;
1397 const char *buf;
1398 struct stat st;
1399 int fd;
42a38cf7
MH
1400 int ret = -1;
1401 int save_errno;
7bd9bcf3 1402
fa96ea1b 1403 *type = 0;
42a38cf7
MH
1404 strbuf_reset(&sb_path);
1405 strbuf_git_path(&sb_path, "%s", refname);
1406 path = sb_path.buf;
7bd9bcf3 1407
7048653a
DT
1408stat_ref:
1409 /*
1410 * We might have to loop back here to avoid a race
1411 * condition: first we lstat() the file, then we try
1412 * to read it as a link or as a file. But if somebody
1413 * changes the type of the file (file <-> directory
1414 * <-> symlink) between the lstat() and reading, then
1415 * we don't want to report that as an error but rather
1416 * try again starting with the lstat().
1417 */
7bd9bcf3 1418
7048653a
DT
1419 if (lstat(path, &st) < 0) {
1420 if (errno != ENOENT)
42a38cf7 1421 goto out;
3a0b6b9a 1422 if (resolve_missing_loose_ref(refname, sha1, type)) {
7048653a 1423 errno = ENOENT;
42a38cf7 1424 goto out;
7bd9bcf3 1425 }
42a38cf7
MH
1426 ret = 0;
1427 goto out;
7bd9bcf3 1428 }
7bd9bcf3 1429
7048653a
DT
1430 /* Follow "normalized" - ie "refs/.." symlinks by hand */
1431 if (S_ISLNK(st.st_mode)) {
42a38cf7
MH
1432 strbuf_reset(&sb_contents);
1433 if (strbuf_readlink(&sb_contents, path, 0) < 0) {
7048653a 1434 if (errno == ENOENT || errno == EINVAL)
7bd9bcf3
MH
1435 /* inconsistent with lstat; retry */
1436 goto stat_ref;
1437 else
42a38cf7 1438 goto out;
7bd9bcf3 1439 }
42a38cf7
MH
1440 if (starts_with(sb_contents.buf, "refs/") &&
1441 !check_refname_format(sb_contents.buf, 0)) {
92b38093 1442 strbuf_swap(&sb_contents, referent);
3a0b6b9a 1443 *type |= REF_ISSYMREF;
42a38cf7
MH
1444 ret = 0;
1445 goto out;
7bd9bcf3 1446 }
7048653a 1447 }
7bd9bcf3 1448
7048653a
DT
1449 /* Is it a directory? */
1450 if (S_ISDIR(st.st_mode)) {
e167a567
MH
1451 /*
1452 * Even though there is a directory where the loose
1453 * ref is supposed to be, there could still be a
1454 * packed ref:
1455 */
3a0b6b9a 1456 if (resolve_missing_loose_ref(refname, sha1, type)) {
e167a567
MH
1457 errno = EISDIR;
1458 goto out;
1459 }
1460 ret = 0;
42a38cf7 1461 goto out;
7048653a
DT
1462 }
1463
1464 /*
1465 * Anything else, just open it and try to use it as
1466 * a ref
1467 */
1468 fd = open(path, O_RDONLY);
1469 if (fd < 0) {
1470 if (errno == ENOENT)
1471 /* inconsistent with lstat; retry */
1472 goto stat_ref;
1473 else
42a38cf7 1474 goto out;
7048653a 1475 }
42a38cf7
MH
1476 strbuf_reset(&sb_contents);
1477 if (strbuf_read(&sb_contents, fd, 256) < 0) {
7048653a
DT
1478 int save_errno = errno;
1479 close(fd);
1480 errno = save_errno;
42a38cf7 1481 goto out;
7048653a
DT
1482 }
1483 close(fd);
42a38cf7
MH
1484 strbuf_rtrim(&sb_contents);
1485 buf = sb_contents.buf;
7048653a
DT
1486 if (starts_with(buf, "ref:")) {
1487 buf += 4;
7bd9bcf3
MH
1488 while (isspace(*buf))
1489 buf++;
7048653a 1490
92b38093
MH
1491 strbuf_reset(referent);
1492 strbuf_addstr(referent, buf);
3a0b6b9a 1493 *type |= REF_ISSYMREF;
42a38cf7
MH
1494 ret = 0;
1495 goto out;
7bd9bcf3 1496 }
7bd9bcf3 1497
7048653a
DT
1498 /*
1499 * Please note that FETCH_HEAD has additional
1500 * data after the sha.
1501 */
1502 if (get_sha1_hex(buf, sha1) ||
1503 (buf[40] != '\0' && !isspace(buf[40]))) {
3a0b6b9a 1504 *type |= REF_ISBROKEN;
7048653a 1505 errno = EINVAL;
42a38cf7 1506 goto out;
7048653a
DT
1507 }
1508
42a38cf7 1509 ret = 0;
7bd9bcf3 1510
42a38cf7
MH
1511out:
1512 save_errno = errno;
7bd9bcf3
MH
1513 strbuf_release(&sb_path);
1514 strbuf_release(&sb_contents);
42a38cf7 1515 errno = save_errno;
7bd9bcf3
MH
1516 return ret;
1517}
1518
1519/*
1520 * Peel the entry (if possible) and return its new peel_status. If
1521 * repeel is true, re-peel the entry even if there is an old peeled
1522 * value that is already stored in it.
1523 *
1524 * It is OK to call this function with a packed reference entry that
1525 * might be stale and might even refer to an object that has since
1526 * been garbage-collected. In such a case, if the entry has
1527 * REF_KNOWS_PEELED then leave the status unchanged and return
1528 * PEEL_PEELED or PEEL_NON_TAG; otherwise, return PEEL_INVALID.
1529 */
1530static enum peel_status peel_entry(struct ref_entry *entry, int repeel)
1531{
1532 enum peel_status status;
1533
1534 if (entry->flag & REF_KNOWS_PEELED) {
1535 if (repeel) {
1536 entry->flag &= ~REF_KNOWS_PEELED;
1537 oidclr(&entry->u.value.peeled);
1538 } else {
1539 return is_null_oid(&entry->u.value.peeled) ?
1540 PEEL_NON_TAG : PEEL_PEELED;
1541 }
1542 }
1543 if (entry->flag & REF_ISBROKEN)
1544 return PEEL_BROKEN;
1545 if (entry->flag & REF_ISSYMREF)
1546 return PEEL_IS_SYMREF;
1547
1548 status = peel_object(entry->u.value.oid.hash, entry->u.value.peeled.hash);
1549 if (status == PEEL_PEELED || status == PEEL_NON_TAG)
1550 entry->flag |= REF_KNOWS_PEELED;
1551 return status;
1552}
1553
1554int peel_ref(const char *refname, unsigned char *sha1)
1555{
1556 int flag;
1557 unsigned char base[20];
1558
1559 if (current_ref && (current_ref->name == refname
1560 || !strcmp(current_ref->name, refname))) {
1561 if (peel_entry(current_ref, 0))
1562 return -1;
1563 hashcpy(sha1, current_ref->u.value.peeled.hash);
1564 return 0;
1565 }
1566
1567 if (read_ref_full(refname, RESOLVE_REF_READING, base, &flag))
1568 return -1;
1569
1570 /*
1571 * If the reference is packed, read its ref_entry from the
1572 * cache in the hope that we already know its peeled value.
1573 * We only try this optimization on packed references because
1574 * (a) forcing the filling of the loose reference cache could
1575 * be expensive and (b) loose references anyway usually do not
1576 * have REF_KNOWS_PEELED.
1577 */
1578 if (flag & REF_ISPACKED) {
1579 struct ref_entry *r = get_packed_ref(refname);
1580 if (r) {
1581 if (peel_entry(r, 0))
1582 return -1;
1583 hashcpy(sha1, r->u.value.peeled.hash);
1584 return 0;
1585 }
1586 }
1587
1588 return peel_object(base, sha1);
1589}
1590
1591/*
1592 * Call fn for each reference in the specified ref_cache, omitting
1593 * references not in the containing_dir of base. fn is called for all
1594 * references, including broken ones. If fn ever returns a non-zero
1595 * value, stop the iteration and return that value; otherwise, return
1596 * 0.
1597 */
1598static int do_for_each_entry(struct ref_cache *refs, const char *base,
1599 each_ref_entry_fn fn, void *cb_data)
1600{
1601 struct packed_ref_cache *packed_ref_cache;
1602 struct ref_dir *loose_dir;
1603 struct ref_dir *packed_dir;
1604 int retval = 0;
1605
1606 /*
1607 * We must make sure that all loose refs are read before accessing the
1608 * packed-refs file; this avoids a race condition in which loose refs
1609 * are migrated to the packed-refs file by a simultaneous process, but
1610 * our in-memory view is from before the migration. get_packed_ref_cache()
1611 * takes care of making sure our view is up to date with what is on
1612 * disk.
1613 */
1614 loose_dir = get_loose_refs(refs);
1615 if (base && *base) {
1616 loose_dir = find_containing_dir(loose_dir, base, 0);
1617 }
1618 if (loose_dir)
1619 prime_ref_dir(loose_dir);
1620
1621 packed_ref_cache = get_packed_ref_cache(refs);
1622 acquire_packed_ref_cache(packed_ref_cache);
1623 packed_dir = get_packed_ref_dir(packed_ref_cache);
1624 if (base && *base) {
1625 packed_dir = find_containing_dir(packed_dir, base, 0);
1626 }
1627
1628 if (packed_dir && loose_dir) {
1629 sort_ref_dir(packed_dir);
1630 sort_ref_dir(loose_dir);
1631 retval = do_for_each_entry_in_dirs(
1632 packed_dir, loose_dir, fn, cb_data);
1633 } else if (packed_dir) {
1634 sort_ref_dir(packed_dir);
1635 retval = do_for_each_entry_in_dir(
1636 packed_dir, 0, fn, cb_data);
1637 } else if (loose_dir) {
1638 sort_ref_dir(loose_dir);
1639 retval = do_for_each_entry_in_dir(
1640 loose_dir, 0, fn, cb_data);
1641 }
1642
1643 release_packed_ref_cache(packed_ref_cache);
1644 return retval;
1645}
1646
1647/*
1648 * Call fn for each reference in the specified ref_cache for which the
1649 * refname begins with base. If trim is non-zero, then trim that many
1650 * characters off the beginning of each refname before passing the
1651 * refname to fn. flags can be DO_FOR_EACH_INCLUDE_BROKEN to include
1652 * broken references in the iteration. If fn ever returns a non-zero
1653 * value, stop the iteration and return that value; otherwise, return
1654 * 0.
1655 */
93770590
DT
1656int do_for_each_ref(const char *submodule, const char *base,
1657 each_ref_fn fn, int trim, int flags, void *cb_data)
7bd9bcf3
MH
1658{
1659 struct ref_entry_cb data;
93770590
DT
1660 struct ref_cache *refs;
1661
1662 refs = get_ref_cache(submodule);
7bd9bcf3
MH
1663 data.base = base;
1664 data.trim = trim;
1665 data.flags = flags;
1666 data.fn = fn;
1667 data.cb_data = cb_data;
1668
1669 if (ref_paranoia < 0)
1670 ref_paranoia = git_env_bool("GIT_REF_PARANOIA", 0);
1671 if (ref_paranoia)
1672 data.flags |= DO_FOR_EACH_INCLUDE_BROKEN;
1673
1674 return do_for_each_entry(refs, base, do_one_ref, &data);
1675}
1676
7bd9bcf3
MH
1677static void unlock_ref(struct ref_lock *lock)
1678{
1679 /* Do not free lock->lk -- atexit() still looks at them */
1680 if (lock->lk)
1681 rollback_lock_file(lock->lk);
1682 free(lock->ref_name);
1683 free(lock->orig_ref_name);
1684 free(lock);
1685}
1686
1687/*
1688 * Verify that the reference locked by lock has the value old_sha1.
1689 * Fail if the reference doesn't exist and mustexist is set. Return 0
1690 * on success. On error, write an error message to err, set errno, and
1691 * return a negative value.
1692 */
1693static int verify_lock(struct ref_lock *lock,
1694 const unsigned char *old_sha1, int mustexist,
1695 struct strbuf *err)
1696{
1697 assert(err);
1698
1699 if (read_ref_full(lock->ref_name,
1700 mustexist ? RESOLVE_REF_READING : 0,
1701 lock->old_oid.hash, NULL)) {
6294dcb4
JK
1702 if (old_sha1) {
1703 int save_errno = errno;
0568c8e9 1704 strbuf_addf(err, "can't verify ref '%s'", lock->ref_name);
6294dcb4
JK
1705 errno = save_errno;
1706 return -1;
1707 } else {
1708 hashclr(lock->old_oid.hash);
1709 return 0;
1710 }
7bd9bcf3 1711 }
6294dcb4 1712 if (old_sha1 && hashcmp(lock->old_oid.hash, old_sha1)) {
0568c8e9 1713 strbuf_addf(err, "ref '%s' is at %s but expected %s",
7bd9bcf3
MH
1714 lock->ref_name,
1715 sha1_to_hex(lock->old_oid.hash),
1716 sha1_to_hex(old_sha1));
1717 errno = EBUSY;
1718 return -1;
1719 }
1720 return 0;
1721}
1722
1723static int remove_empty_directories(struct strbuf *path)
1724{
1725 /*
1726 * we want to create a file but there is a directory there;
1727 * if that is an empty directory (or a directory that contains
1728 * only empty directories), remove them.
1729 */
1730 return remove_dir_recursively(path, REMOVE_DIR_EMPTY_ONLY);
1731}
1732
1733/*
1734 * Locks a ref returning the lock on success and NULL on failure.
1735 * On failure errno is set to something meaningful.
1736 */
1737static struct ref_lock *lock_ref_sha1_basic(const char *refname,
1738 const unsigned char *old_sha1,
1739 const struct string_list *extras,
1740 const struct string_list *skip,
bcb497d0 1741 unsigned int flags, int *type,
7bd9bcf3
MH
1742 struct strbuf *err)
1743{
1744 struct strbuf ref_file = STRBUF_INIT;
1745 struct strbuf orig_ref_file = STRBUF_INIT;
1746 const char *orig_refname = refname;
1747 struct ref_lock *lock;
1748 int last_errno = 0;
2859dcd4 1749 int lflags = 0;
7bd9bcf3
MH
1750 int mustexist = (old_sha1 && !is_null_sha1(old_sha1));
1751 int resolve_flags = 0;
1752 int attempts_remaining = 3;
1753
1754 assert(err);
1755
1756 lock = xcalloc(1, sizeof(struct ref_lock));
1757
1758 if (mustexist)
1759 resolve_flags |= RESOLVE_REF_READING;
2859dcd4 1760 if (flags & REF_DELETING)
7bd9bcf3 1761 resolve_flags |= RESOLVE_REF_ALLOW_BAD_NAME;
2859dcd4
JK
1762 if (flags & REF_NODEREF) {
1763 resolve_flags |= RESOLVE_REF_NO_RECURSE;
1764 lflags |= LOCK_NO_DEREF;
7bd9bcf3
MH
1765 }
1766
1767 refname = resolve_ref_unsafe(refname, resolve_flags,
bcb497d0 1768 lock->old_oid.hash, type);
7bd9bcf3
MH
1769 if (!refname && errno == EISDIR) {
1770 /*
1771 * we are trying to lock foo but we used to
1772 * have foo/bar which now does not exist;
1773 * it is normal for the empty directory 'foo'
1774 * to remain.
1775 */
1776 strbuf_git_path(&orig_ref_file, "%s", orig_refname);
1777 if (remove_empty_directories(&orig_ref_file)) {
1778 last_errno = errno;
1779 if (!verify_refname_available_dir(orig_refname, extras, skip,
1780 get_loose_refs(&ref_cache), err))
1781 strbuf_addf(err, "there are still refs under '%s'",
1782 orig_refname);
1783 goto error_return;
1784 }
1785 refname = resolve_ref_unsafe(orig_refname, resolve_flags,
bcb497d0 1786 lock->old_oid.hash, type);
7bd9bcf3 1787 }
7bd9bcf3
MH
1788 if (!refname) {
1789 last_errno = errno;
1790 if (last_errno != ENOTDIR ||
1791 !verify_refname_available_dir(orig_refname, extras, skip,
1792 get_loose_refs(&ref_cache), err))
0568c8e9 1793 strbuf_addf(err, "unable to resolve reference '%s': %s",
7bd9bcf3
MH
1794 orig_refname, strerror(last_errno));
1795
1796 goto error_return;
1797 }
2859dcd4
JK
1798
1799 if (flags & REF_NODEREF)
1800 refname = orig_refname;
1801
7bd9bcf3
MH
1802 /*
1803 * If the ref did not exist and we are creating it, make sure
1804 * there is no existing packed ref whose name begins with our
1805 * refname, nor a packed ref whose name is a proper prefix of
1806 * our refname.
1807 */
1808 if (is_null_oid(&lock->old_oid) &&
1809 verify_refname_available_dir(refname, extras, skip,
1810 get_packed_refs(&ref_cache), err)) {
1811 last_errno = ENOTDIR;
1812 goto error_return;
1813 }
1814
1815 lock->lk = xcalloc(1, sizeof(struct lock_file));
1816
7bd9bcf3
MH
1817 lock->ref_name = xstrdup(refname);
1818 lock->orig_ref_name = xstrdup(orig_refname);
1819 strbuf_git_path(&ref_file, "%s", refname);
1820
1821 retry:
1822 switch (safe_create_leading_directories_const(ref_file.buf)) {
1823 case SCLD_OK:
1824 break; /* success */
1825 case SCLD_VANISHED:
1826 if (--attempts_remaining > 0)
1827 goto retry;
1828 /* fall through */
1829 default:
1830 last_errno = errno;
0568c8e9 1831 strbuf_addf(err, "unable to create directory for '%s'",
7bd9bcf3
MH
1832 ref_file.buf);
1833 goto error_return;
1834 }
1835
1836 if (hold_lock_file_for_update(lock->lk, ref_file.buf, lflags) < 0) {
1837 last_errno = errno;
1838 if (errno == ENOENT && --attempts_remaining > 0)
1839 /*
1840 * Maybe somebody just deleted one of the
1841 * directories leading to ref_file. Try
1842 * again:
1843 */
1844 goto retry;
1845 else {
1846 unable_to_lock_message(ref_file.buf, errno, err);
1847 goto error_return;
1848 }
1849 }
6294dcb4 1850 if (verify_lock(lock, old_sha1, mustexist, err)) {
7bd9bcf3
MH
1851 last_errno = errno;
1852 goto error_return;
1853 }
1854 goto out;
1855
1856 error_return:
1857 unlock_ref(lock);
1858 lock = NULL;
1859
1860 out:
1861 strbuf_release(&ref_file);
1862 strbuf_release(&orig_ref_file);
1863 errno = last_errno;
1864 return lock;
1865}
1866
1867/*
1868 * Write an entry to the packed-refs file for the specified refname.
1869 * If peeled is non-NULL, write it as the entry's peeled value.
1870 */
1871static void write_packed_entry(FILE *fh, char *refname, unsigned char *sha1,
1872 unsigned char *peeled)
1873{
1874 fprintf_or_die(fh, "%s %s\n", sha1_to_hex(sha1), refname);
1875 if (peeled)
1876 fprintf_or_die(fh, "^%s\n", sha1_to_hex(peeled));
1877}
1878
1879/*
1880 * An each_ref_entry_fn that writes the entry to a packed-refs file.
1881 */
1882static int write_packed_entry_fn(struct ref_entry *entry, void *cb_data)
1883{
1884 enum peel_status peel_status = peel_entry(entry, 0);
1885
1886 if (peel_status != PEEL_PEELED && peel_status != PEEL_NON_TAG)
1887 error("internal error: %s is not a valid packed reference!",
1888 entry->name);
1889 write_packed_entry(cb_data, entry->name, entry->u.value.oid.hash,
1890 peel_status == PEEL_PEELED ?
1891 entry->u.value.peeled.hash : NULL);
1892 return 0;
1893}
1894
1895/*
1896 * Lock the packed-refs file for writing. Flags is passed to
1897 * hold_lock_file_for_update(). Return 0 on success. On errors, set
1898 * errno appropriately and return a nonzero value.
1899 */
1900static int lock_packed_refs(int flags)
1901{
1902 static int timeout_configured = 0;
1903 static int timeout_value = 1000;
1904
1905 struct packed_ref_cache *packed_ref_cache;
1906
1907 if (!timeout_configured) {
1908 git_config_get_int("core.packedrefstimeout", &timeout_value);
1909 timeout_configured = 1;
1910 }
1911
1912 if (hold_lock_file_for_update_timeout(
1913 &packlock, git_path("packed-refs"),
1914 flags, timeout_value) < 0)
1915 return -1;
1916 /*
1917 * Get the current packed-refs while holding the lock. If the
1918 * packed-refs file has been modified since we last read it,
1919 * this will automatically invalidate the cache and re-read
1920 * the packed-refs file.
1921 */
1922 packed_ref_cache = get_packed_ref_cache(&ref_cache);
1923 packed_ref_cache->lock = &packlock;
1924 /* Increment the reference count to prevent it from being freed: */
1925 acquire_packed_ref_cache(packed_ref_cache);
1926 return 0;
1927}
1928
1929/*
1930 * Write the current version of the packed refs cache from memory to
1931 * disk. The packed-refs file must already be locked for writing (see
1932 * lock_packed_refs()). Return zero on success. On errors, set errno
1933 * and return a nonzero value
1934 */
1935static int commit_packed_refs(void)
1936{
1937 struct packed_ref_cache *packed_ref_cache =
1938 get_packed_ref_cache(&ref_cache);
1939 int error = 0;
1940 int save_errno = 0;
1941 FILE *out;
1942
1943 if (!packed_ref_cache->lock)
1944 die("internal error: packed-refs not locked");
1945
1946 out = fdopen_lock_file(packed_ref_cache->lock, "w");
1947 if (!out)
1948 die_errno("unable to fdopen packed-refs descriptor");
1949
1950 fprintf_or_die(out, "%s", PACKED_REFS_HEADER);
1951 do_for_each_entry_in_dir(get_packed_ref_dir(packed_ref_cache),
1952 0, write_packed_entry_fn, out);
1953
1954 if (commit_lock_file(packed_ref_cache->lock)) {
1955 save_errno = errno;
1956 error = -1;
1957 }
1958 packed_ref_cache->lock = NULL;
1959 release_packed_ref_cache(packed_ref_cache);
1960 errno = save_errno;
1961 return error;
1962}
1963
1964/*
1965 * Rollback the lockfile for the packed-refs file, and discard the
1966 * in-memory packed reference cache. (The packed-refs file will be
1967 * read anew if it is needed again after this function is called.)
1968 */
1969static void rollback_packed_refs(void)
1970{
1971 struct packed_ref_cache *packed_ref_cache =
1972 get_packed_ref_cache(&ref_cache);
1973
1974 if (!packed_ref_cache->lock)
1975 die("internal error: packed-refs not locked");
1976 rollback_lock_file(packed_ref_cache->lock);
1977 packed_ref_cache->lock = NULL;
1978 release_packed_ref_cache(packed_ref_cache);
1979 clear_packed_ref_cache(&ref_cache);
1980}
1981
1982struct ref_to_prune {
1983 struct ref_to_prune *next;
1984 unsigned char sha1[20];
1985 char name[FLEX_ARRAY];
1986};
1987
1988struct pack_refs_cb_data {
1989 unsigned int flags;
1990 struct ref_dir *packed_refs;
1991 struct ref_to_prune *ref_to_prune;
1992};
1993
1994/*
1995 * An each_ref_entry_fn that is run over loose references only. If
1996 * the loose reference can be packed, add an entry in the packed ref
1997 * cache. If the reference should be pruned, also add it to
1998 * ref_to_prune in the pack_refs_cb_data.
1999 */
2000static int pack_if_possible_fn(struct ref_entry *entry, void *cb_data)
2001{
2002 struct pack_refs_cb_data *cb = cb_data;
2003 enum peel_status peel_status;
2004 struct ref_entry *packed_entry;
2005 int is_tag_ref = starts_with(entry->name, "refs/tags/");
2006
2007 /* Do not pack per-worktree refs: */
2008 if (ref_type(entry->name) != REF_TYPE_NORMAL)
2009 return 0;
2010
2011 /* ALWAYS pack tags */
2012 if (!(cb->flags & PACK_REFS_ALL) && !is_tag_ref)
2013 return 0;
2014
2015 /* Do not pack symbolic or broken refs: */
2016 if ((entry->flag & REF_ISSYMREF) || !ref_resolves_to_object(entry))
2017 return 0;
2018
2019 /* Add a packed ref cache entry equivalent to the loose entry. */
2020 peel_status = peel_entry(entry, 1);
2021 if (peel_status != PEEL_PEELED && peel_status != PEEL_NON_TAG)
2022 die("internal error peeling reference %s (%s)",
2023 entry->name, oid_to_hex(&entry->u.value.oid));
2024 packed_entry = find_ref(cb->packed_refs, entry->name);
2025 if (packed_entry) {
2026 /* Overwrite existing packed entry with info from loose entry */
2027 packed_entry->flag = REF_ISPACKED | REF_KNOWS_PEELED;
2028 oidcpy(&packed_entry->u.value.oid, &entry->u.value.oid);
2029 } else {
2030 packed_entry = create_ref_entry(entry->name, entry->u.value.oid.hash,
2031 REF_ISPACKED | REF_KNOWS_PEELED, 0);
2032 add_ref(cb->packed_refs, packed_entry);
2033 }
2034 oidcpy(&packed_entry->u.value.peeled, &entry->u.value.peeled);
2035
2036 /* Schedule the loose reference for pruning if requested. */
2037 if ((cb->flags & PACK_REFS_PRUNE)) {
96ffc06f
JK
2038 struct ref_to_prune *n;
2039 FLEX_ALLOC_STR(n, name, entry->name);
7bd9bcf3 2040 hashcpy(n->sha1, entry->u.value.oid.hash);
7bd9bcf3
MH
2041 n->next = cb->ref_to_prune;
2042 cb->ref_to_prune = n;
2043 }
2044 return 0;
2045}
2046
2047/*
2048 * Remove empty parents, but spare refs/ and immediate subdirs.
2049 * Note: munges *name.
2050 */
2051static void try_remove_empty_parents(char *name)
2052{
2053 char *p, *q;
2054 int i;
2055 p = name;
2056 for (i = 0; i < 2; i++) { /* refs/{heads,tags,...}/ */
2057 while (*p && *p != '/')
2058 p++;
2059 /* tolerate duplicate slashes; see check_refname_format() */
2060 while (*p == '/')
2061 p++;
2062 }
2063 for (q = p; *q; q++)
2064 ;
2065 while (1) {
2066 while (q > p && *q != '/')
2067 q--;
2068 while (q > p && *(q-1) == '/')
2069 q--;
2070 if (q == p)
2071 break;
2072 *q = '\0';
2073 if (rmdir(git_path("%s", name)))
2074 break;
2075 }
2076}
2077
2078/* make sure nobody touched the ref, and unlink */
2079static void prune_ref(struct ref_to_prune *r)
2080{
2081 struct ref_transaction *transaction;
2082 struct strbuf err = STRBUF_INIT;
2083
2084 if (check_refname_format(r->name, 0))
2085 return;
2086
2087 transaction = ref_transaction_begin(&err);
2088 if (!transaction ||
2089 ref_transaction_delete(transaction, r->name, r->sha1,
c52ce248 2090 REF_ISPRUNING | REF_NODEREF, NULL, &err) ||
7bd9bcf3
MH
2091 ref_transaction_commit(transaction, &err)) {
2092 ref_transaction_free(transaction);
2093 error("%s", err.buf);
2094 strbuf_release(&err);
2095 return;
2096 }
2097 ref_transaction_free(transaction);
2098 strbuf_release(&err);
2099 try_remove_empty_parents(r->name);
2100}
2101
2102static void prune_refs(struct ref_to_prune *r)
2103{
2104 while (r) {
2105 prune_ref(r);
2106 r = r->next;
2107 }
2108}
2109
2110int pack_refs(unsigned int flags)
2111{
2112 struct pack_refs_cb_data cbdata;
2113
2114 memset(&cbdata, 0, sizeof(cbdata));
2115 cbdata.flags = flags;
2116
2117 lock_packed_refs(LOCK_DIE_ON_ERROR);
2118 cbdata.packed_refs = get_packed_refs(&ref_cache);
2119
2120 do_for_each_entry_in_dir(get_loose_refs(&ref_cache), 0,
2121 pack_if_possible_fn, &cbdata);
2122
2123 if (commit_packed_refs())
2124 die_errno("unable to overwrite old ref-pack file");
2125
2126 prune_refs(cbdata.ref_to_prune);
2127 return 0;
2128}
2129
2130/*
2131 * Rewrite the packed-refs file, omitting any refs listed in
2132 * 'refnames'. On error, leave packed-refs unchanged, write an error
2133 * message to 'err', and return a nonzero value.
2134 *
2135 * The refs in 'refnames' needn't be sorted. `err` must not be NULL.
2136 */
2137static int repack_without_refs(struct string_list *refnames, struct strbuf *err)
2138{
2139 struct ref_dir *packed;
2140 struct string_list_item *refname;
2141 int ret, needs_repacking = 0, removed = 0;
2142
2143 assert(err);
2144
2145 /* Look for a packed ref */
2146 for_each_string_list_item(refname, refnames) {
2147 if (get_packed_ref(refname->string)) {
2148 needs_repacking = 1;
2149 break;
2150 }
2151 }
2152
2153 /* Avoid locking if we have nothing to do */
2154 if (!needs_repacking)
2155 return 0; /* no refname exists in packed refs */
2156
2157 if (lock_packed_refs(0)) {
2158 unable_to_lock_message(git_path("packed-refs"), errno, err);
2159 return -1;
2160 }
2161 packed = get_packed_refs(&ref_cache);
2162
2163 /* Remove refnames from the cache */
2164 for_each_string_list_item(refname, refnames)
2165 if (remove_entry(packed, refname->string) != -1)
2166 removed = 1;
2167 if (!removed) {
2168 /*
2169 * All packed entries disappeared while we were
2170 * acquiring the lock.
2171 */
2172 rollback_packed_refs();
2173 return 0;
2174 }
2175
2176 /* Write what remains */
2177 ret = commit_packed_refs();
2178 if (ret)
2179 strbuf_addf(err, "unable to overwrite old ref-pack file: %s",
2180 strerror(errno));
2181 return ret;
2182}
2183
2184static int delete_ref_loose(struct ref_lock *lock, int flag, struct strbuf *err)
2185{
2186 assert(err);
2187
2188 if (!(flag & REF_ISPACKED) || flag & REF_ISSYMREF) {
2189 /*
2190 * loose. The loose file name is the same as the
2191 * lockfile name, minus ".lock":
2192 */
2193 char *loose_filename = get_locked_file_path(lock->lk);
2194 int res = unlink_or_msg(loose_filename, err);
2195 free(loose_filename);
2196 if (res)
2197 return 1;
2198 }
2199 return 0;
2200}
2201
2202int delete_refs(struct string_list *refnames)
2203{
2204 struct strbuf err = STRBUF_INIT;
2205 int i, result = 0;
2206
2207 if (!refnames->nr)
2208 return 0;
2209
2210 result = repack_without_refs(refnames, &err);
2211 if (result) {
2212 /*
2213 * If we failed to rewrite the packed-refs file, then
2214 * it is unsafe to try to remove loose refs, because
2215 * doing so might expose an obsolete packed value for
2216 * a reference that might even point at an object that
2217 * has been garbage collected.
2218 */
2219 if (refnames->nr == 1)
2220 error(_("could not delete reference %s: %s"),
2221 refnames->items[0].string, err.buf);
2222 else
2223 error(_("could not delete references: %s"), err.buf);
2224
2225 goto out;
2226 }
2227
2228 for (i = 0; i < refnames->nr; i++) {
2229 const char *refname = refnames->items[i].string;
2230
2231 if (delete_ref(refname, NULL, 0))
2232 result |= error(_("could not remove reference %s"), refname);
2233 }
2234
2235out:
2236 strbuf_release(&err);
2237 return result;
2238}
2239
2240/*
2241 * People using contrib's git-new-workdir have .git/logs/refs ->
2242 * /some/other/path/.git/logs/refs, and that may live on another device.
2243 *
2244 * IOW, to avoid cross device rename errors, the temporary renamed log must
2245 * live into logs/refs.
2246 */
2247#define TMP_RENAMED_LOG "logs/refs/.tmp-renamed-log"
2248
2249static int rename_tmp_log(const char *newrefname)
2250{
2251 int attempts_remaining = 4;
2252 struct strbuf path = STRBUF_INIT;
2253 int ret = -1;
2254
2255 retry:
2256 strbuf_reset(&path);
2257 strbuf_git_path(&path, "logs/%s", newrefname);
2258 switch (safe_create_leading_directories_const(path.buf)) {
2259 case SCLD_OK:
2260 break; /* success */
2261 case SCLD_VANISHED:
2262 if (--attempts_remaining > 0)
2263 goto retry;
2264 /* fall through */
2265 default:
2266 error("unable to create directory for %s", newrefname);
2267 goto out;
2268 }
2269
2270 if (rename(git_path(TMP_RENAMED_LOG), path.buf)) {
2271 if ((errno==EISDIR || errno==ENOTDIR) && --attempts_remaining > 0) {
2272 /*
2273 * rename(a, b) when b is an existing
2274 * directory ought to result in ISDIR, but
2275 * Solaris 5.8 gives ENOTDIR. Sheesh.
2276 */
2277 if (remove_empty_directories(&path)) {
2278 error("Directory not empty: logs/%s", newrefname);
2279 goto out;
2280 }
2281 goto retry;
2282 } else if (errno == ENOENT && --attempts_remaining > 0) {
2283 /*
2284 * Maybe another process just deleted one of
2285 * the directories in the path to newrefname.
2286 * Try again from the beginning.
2287 */
2288 goto retry;
2289 } else {
2290 error("unable to move logfile "TMP_RENAMED_LOG" to logs/%s: %s",
2291 newrefname, strerror(errno));
2292 goto out;
2293 }
2294 }
2295 ret = 0;
2296out:
2297 strbuf_release(&path);
2298 return ret;
2299}
2300
2301int verify_refname_available(const char *newname,
3a8af7be
MH
2302 const struct string_list *extras,
2303 const struct string_list *skip,
7bd9bcf3
MH
2304 struct strbuf *err)
2305{
2306 struct ref_dir *packed_refs = get_packed_refs(&ref_cache);
2307 struct ref_dir *loose_refs = get_loose_refs(&ref_cache);
2308
2309 if (verify_refname_available_dir(newname, extras, skip,
2310 packed_refs, err) ||
2311 verify_refname_available_dir(newname, extras, skip,
2312 loose_refs, err))
2313 return -1;
2314
2315 return 0;
2316}
2317
7bd9bcf3
MH
2318static int write_ref_to_lockfile(struct ref_lock *lock,
2319 const unsigned char *sha1, struct strbuf *err);
2320static int commit_ref_update(struct ref_lock *lock,
2321 const unsigned char *sha1, const char *logmsg,
2322 int flags, struct strbuf *err);
2323
2324int rename_ref(const char *oldrefname, const char *newrefname, const char *logmsg)
2325{
2326 unsigned char sha1[20], orig_sha1[20];
2327 int flag = 0, logmoved = 0;
2328 struct ref_lock *lock;
2329 struct stat loginfo;
2330 int log = !lstat(git_path("logs/%s", oldrefname), &loginfo);
7bd9bcf3
MH
2331 struct strbuf err = STRBUF_INIT;
2332
2333 if (log && S_ISLNK(loginfo.st_mode))
2334 return error("reflog for %s is a symlink", oldrefname);
2335
12fd3496
DT
2336 if (!resolve_ref_unsafe(oldrefname, RESOLVE_REF_READING | RESOLVE_REF_NO_RECURSE,
2337 orig_sha1, &flag))
e711b1af
MH
2338 return error("refname %s not found", oldrefname);
2339
7bd9bcf3
MH
2340 if (flag & REF_ISSYMREF)
2341 return error("refname %s is a symbolic ref, renaming it is not supported",
2342 oldrefname);
7bd9bcf3
MH
2343 if (!rename_ref_available(oldrefname, newrefname))
2344 return 1;
2345
2346 if (log && rename(git_path("logs/%s", oldrefname), git_path(TMP_RENAMED_LOG)))
2347 return error("unable to move logfile logs/%s to "TMP_RENAMED_LOG": %s",
2348 oldrefname, strerror(errno));
2349
2350 if (delete_ref(oldrefname, orig_sha1, REF_NODEREF)) {
2351 error("unable to delete old %s", oldrefname);
2352 goto rollback;
2353 }
2354
12fd3496
DT
2355 /*
2356 * Since we are doing a shallow lookup, sha1 is not the
2357 * correct value to pass to delete_ref as old_sha1. But that
2358 * doesn't matter, because an old_sha1 check wouldn't add to
2359 * the safety anyway; we want to delete the reference whatever
2360 * its current value.
2361 */
2362 if (!read_ref_full(newrefname, RESOLVE_REF_READING | RESOLVE_REF_NO_RECURSE,
2363 sha1, NULL) &&
2364 delete_ref(newrefname, NULL, REF_NODEREF)) {
7bd9bcf3
MH
2365 if (errno==EISDIR) {
2366 struct strbuf path = STRBUF_INIT;
2367 int result;
2368
2369 strbuf_git_path(&path, "%s", newrefname);
2370 result = remove_empty_directories(&path);
2371 strbuf_release(&path);
2372
2373 if (result) {
2374 error("Directory not empty: %s", newrefname);
2375 goto rollback;
2376 }
2377 } else {
2378 error("unable to delete existing %s", newrefname);
2379 goto rollback;
2380 }
2381 }
2382
2383 if (log && rename_tmp_log(newrefname))
2384 goto rollback;
2385
2386 logmoved = log;
2387
12fd3496
DT
2388 lock = lock_ref_sha1_basic(newrefname, NULL, NULL, NULL, REF_NODEREF,
2389 NULL, &err);
7bd9bcf3
MH
2390 if (!lock) {
2391 error("unable to rename '%s' to '%s': %s", oldrefname, newrefname, err.buf);
2392 strbuf_release(&err);
2393 goto rollback;
2394 }
2395 hashcpy(lock->old_oid.hash, orig_sha1);
2396
2397 if (write_ref_to_lockfile(lock, orig_sha1, &err) ||
2398 commit_ref_update(lock, orig_sha1, logmsg, 0, &err)) {
2399 error("unable to write current sha1 into %s: %s", newrefname, err.buf);
2400 strbuf_release(&err);
2401 goto rollback;
2402 }
2403
2404 return 0;
2405
2406 rollback:
12fd3496
DT
2407 lock = lock_ref_sha1_basic(oldrefname, NULL, NULL, NULL, REF_NODEREF,
2408 NULL, &err);
7bd9bcf3
MH
2409 if (!lock) {
2410 error("unable to lock %s for rollback: %s", oldrefname, err.buf);
2411 strbuf_release(&err);
2412 goto rollbacklog;
2413 }
2414
2415 flag = log_all_ref_updates;
2416 log_all_ref_updates = 0;
2417 if (write_ref_to_lockfile(lock, orig_sha1, &err) ||
2418 commit_ref_update(lock, orig_sha1, NULL, 0, &err)) {
2419 error("unable to write current sha1 into %s: %s", oldrefname, err.buf);
2420 strbuf_release(&err);
2421 }
2422 log_all_ref_updates = flag;
2423
2424 rollbacklog:
2425 if (logmoved && rename(git_path("logs/%s", newrefname), git_path("logs/%s", oldrefname)))
2426 error("unable to restore logfile %s from %s: %s",
2427 oldrefname, newrefname, strerror(errno));
2428 if (!logmoved && log &&
2429 rename(git_path(TMP_RENAMED_LOG), git_path("logs/%s", oldrefname)))
2430 error("unable to restore logfile %s from "TMP_RENAMED_LOG": %s",
2431 oldrefname, strerror(errno));
2432
2433 return 1;
2434}
2435
2436static int close_ref(struct ref_lock *lock)
2437{
2438 if (close_lock_file(lock->lk))
2439 return -1;
2440 return 0;
2441}
2442
2443static int commit_ref(struct ref_lock *lock)
2444{
5387c0d8
MH
2445 char *path = get_locked_file_path(lock->lk);
2446 struct stat st;
2447
2448 if (!lstat(path, &st) && S_ISDIR(st.st_mode)) {
2449 /*
2450 * There is a directory at the path we want to rename
2451 * the lockfile to. Hopefully it is empty; try to
2452 * delete it.
2453 */
2454 size_t len = strlen(path);
2455 struct strbuf sb_path = STRBUF_INIT;
2456
2457 strbuf_attach(&sb_path, path, len, len);
2458
2459 /*
2460 * If this fails, commit_lock_file() will also fail
2461 * and will report the problem.
2462 */
2463 remove_empty_directories(&sb_path);
2464 strbuf_release(&sb_path);
2465 } else {
2466 free(path);
2467 }
2468
7bd9bcf3
MH
2469 if (commit_lock_file(lock->lk))
2470 return -1;
2471 return 0;
2472}
2473
2474/*
2475 * Create a reflog for a ref. If force_create = 0, the reflog will
2476 * only be created for certain refs (those for which
2477 * should_autocreate_reflog returns non-zero. Otherwise, create it
2478 * regardless of the ref name. Fill in *err and return -1 on failure.
2479 */
2480static int log_ref_setup(const char *refname, struct strbuf *logfile, struct strbuf *err, int force_create)
2481{
2482 int logfd, oflags = O_APPEND | O_WRONLY;
2483
2484 strbuf_git_path(logfile, "logs/%s", refname);
2485 if (force_create || should_autocreate_reflog(refname)) {
2486 if (safe_create_leading_directories(logfile->buf) < 0) {
0568c8e9 2487 strbuf_addf(err, "unable to create directory for '%s': "
7bd9bcf3
MH
2488 "%s", logfile->buf, strerror(errno));
2489 return -1;
2490 }
2491 oflags |= O_CREAT;
2492 }
2493
2494 logfd = open(logfile->buf, oflags, 0666);
2495 if (logfd < 0) {
2496 if (!(oflags & O_CREAT) && (errno == ENOENT || errno == EISDIR))
2497 return 0;
2498
2499 if (errno == EISDIR) {
2500 if (remove_empty_directories(logfile)) {
0568c8e9 2501 strbuf_addf(err, "there are still logs under "
7bd9bcf3
MH
2502 "'%s'", logfile->buf);
2503 return -1;
2504 }
2505 logfd = open(logfile->buf, oflags, 0666);
2506 }
2507
2508 if (logfd < 0) {
0568c8e9 2509 strbuf_addf(err, "unable to append to '%s': %s",
7bd9bcf3
MH
2510 logfile->buf, strerror(errno));
2511 return -1;
2512 }
2513 }
2514
2515 adjust_shared_perm(logfile->buf);
2516 close(logfd);
2517 return 0;
2518}
2519
2520
2521int safe_create_reflog(const char *refname, int force_create, struct strbuf *err)
2522{
2523 int ret;
2524 struct strbuf sb = STRBUF_INIT;
2525
2526 ret = log_ref_setup(refname, &sb, err, force_create);
2527 strbuf_release(&sb);
2528 return ret;
2529}
2530
2531static int log_ref_write_fd(int fd, const unsigned char *old_sha1,
2532 const unsigned char *new_sha1,
2533 const char *committer, const char *msg)
2534{
2535 int msglen, written;
2536 unsigned maxlen, len;
2537 char *logrec;
2538
2539 msglen = msg ? strlen(msg) : 0;
2540 maxlen = strlen(committer) + msglen + 100;
2541 logrec = xmalloc(maxlen);
2542 len = xsnprintf(logrec, maxlen, "%s %s %s\n",
2543 sha1_to_hex(old_sha1),
2544 sha1_to_hex(new_sha1),
2545 committer);
2546 if (msglen)
2547 len += copy_reflog_msg(logrec + len - 1, msg) - 1;
2548
2549 written = len <= maxlen ? write_in_full(fd, logrec, len) : -1;
2550 free(logrec);
2551 if (written != len)
2552 return -1;
2553
2554 return 0;
2555}
2556
2557static int log_ref_write_1(const char *refname, const unsigned char *old_sha1,
2558 const unsigned char *new_sha1, const char *msg,
2559 struct strbuf *logfile, int flags,
2560 struct strbuf *err)
2561{
2562 int logfd, result, oflags = O_APPEND | O_WRONLY;
2563
2564 if (log_all_ref_updates < 0)
2565 log_all_ref_updates = !is_bare_repository();
2566
2567 result = log_ref_setup(refname, logfile, err, flags & REF_FORCE_CREATE_REFLOG);
2568
2569 if (result)
2570 return result;
2571
2572 logfd = open(logfile->buf, oflags);
2573 if (logfd < 0)
2574 return 0;
2575 result = log_ref_write_fd(logfd, old_sha1, new_sha1,
2576 git_committer_info(0), msg);
2577 if (result) {
0568c8e9 2578 strbuf_addf(err, "unable to append to '%s': %s", logfile->buf,
7bd9bcf3
MH
2579 strerror(errno));
2580 close(logfd);
2581 return -1;
2582 }
2583 if (close(logfd)) {
0568c8e9 2584 strbuf_addf(err, "unable to append to '%s': %s", logfile->buf,
7bd9bcf3
MH
2585 strerror(errno));
2586 return -1;
2587 }
2588 return 0;
2589}
2590
2591static int log_ref_write(const char *refname, const unsigned char *old_sha1,
2592 const unsigned char *new_sha1, const char *msg,
2593 int flags, struct strbuf *err)
5f3c3a4e
DT
2594{
2595 return files_log_ref_write(refname, old_sha1, new_sha1, msg, flags,
2596 err);
2597}
2598
2599int files_log_ref_write(const char *refname, const unsigned char *old_sha1,
2600 const unsigned char *new_sha1, const char *msg,
2601 int flags, struct strbuf *err)
7bd9bcf3
MH
2602{
2603 struct strbuf sb = STRBUF_INIT;
2604 int ret = log_ref_write_1(refname, old_sha1, new_sha1, msg, &sb, flags,
2605 err);
2606 strbuf_release(&sb);
2607 return ret;
2608}
2609
2610/*
2611 * Write sha1 into the open lockfile, then close the lockfile. On
2612 * errors, rollback the lockfile, fill in *err and
2613 * return -1.
2614 */
2615static int write_ref_to_lockfile(struct ref_lock *lock,
2616 const unsigned char *sha1, struct strbuf *err)
2617{
2618 static char term = '\n';
2619 struct object *o;
2620 int fd;
2621
2622 o = parse_object(sha1);
2623 if (!o) {
2624 strbuf_addf(err,
0568c8e9 2625 "trying to write ref '%s' with nonexistent object %s",
7bd9bcf3
MH
2626 lock->ref_name, sha1_to_hex(sha1));
2627 unlock_ref(lock);
2628 return -1;
2629 }
2630 if (o->type != OBJ_COMMIT && is_branch(lock->ref_name)) {
2631 strbuf_addf(err,
0568c8e9 2632 "trying to write non-commit object %s to branch '%s'",
7bd9bcf3
MH
2633 sha1_to_hex(sha1), lock->ref_name);
2634 unlock_ref(lock);
2635 return -1;
2636 }
2637 fd = get_lock_file_fd(lock->lk);
2638 if (write_in_full(fd, sha1_to_hex(sha1), 40) != 40 ||
2639 write_in_full(fd, &term, 1) != 1 ||
2640 close_ref(lock) < 0) {
2641 strbuf_addf(err,
0568c8e9 2642 "couldn't write '%s'", get_lock_file_path(lock->lk));
7bd9bcf3
MH
2643 unlock_ref(lock);
2644 return -1;
2645 }
2646 return 0;
2647}
2648
2649/*
2650 * Commit a change to a loose reference that has already been written
2651 * to the loose reference lockfile. Also update the reflogs if
2652 * necessary, using the specified lockmsg (which can be NULL).
2653 */
2654static int commit_ref_update(struct ref_lock *lock,
2655 const unsigned char *sha1, const char *logmsg,
2656 int flags, struct strbuf *err)
2657{
2658 clear_loose_ref_cache(&ref_cache);
2659 if (log_ref_write(lock->ref_name, lock->old_oid.hash, sha1, logmsg, flags, err) < 0 ||
2660 (strcmp(lock->ref_name, lock->orig_ref_name) &&
2661 log_ref_write(lock->orig_ref_name, lock->old_oid.hash, sha1, logmsg, flags, err) < 0)) {
2662 char *old_msg = strbuf_detach(err, NULL);
0568c8e9 2663 strbuf_addf(err, "cannot update the ref '%s': %s",
7bd9bcf3
MH
2664 lock->ref_name, old_msg);
2665 free(old_msg);
2666 unlock_ref(lock);
2667 return -1;
2668 }
2669 if (strcmp(lock->orig_ref_name, "HEAD") != 0) {
2670 /*
2671 * Special hack: If a branch is updated directly and HEAD
2672 * points to it (may happen on the remote side of a push
2673 * for example) then logically the HEAD reflog should be
2674 * updated too.
2675 * A generic solution implies reverse symref information,
2676 * but finding all symrefs pointing to the given branch
2677 * would be rather costly for this rare event (the direct
2678 * update of a branch) to be worth it. So let's cheat and
2679 * check with HEAD only which should cover 99% of all usage
2680 * scenarios (even 100% of the default ones).
2681 */
2682 unsigned char head_sha1[20];
2683 int head_flag;
2684 const char *head_ref;
2685 head_ref = resolve_ref_unsafe("HEAD", RESOLVE_REF_READING,
2686 head_sha1, &head_flag);
2687 if (head_ref && (head_flag & REF_ISSYMREF) &&
2688 !strcmp(head_ref, lock->ref_name)) {
2689 struct strbuf log_err = STRBUF_INIT;
2690 if (log_ref_write("HEAD", lock->old_oid.hash, sha1,
2691 logmsg, 0, &log_err)) {
2692 error("%s", log_err.buf);
2693 strbuf_release(&log_err);
2694 }
2695 }
2696 }
d99aa884 2697 if (!(flags & REF_LOG_ONLY) && commit_ref(lock)) {
0568c8e9 2698 strbuf_addf(err, "couldn't set '%s'", lock->ref_name);
7bd9bcf3
MH
2699 unlock_ref(lock);
2700 return -1;
2701 }
2702
2703 unlock_ref(lock);
2704 return 0;
2705}
2706
370e5ad6 2707static int create_ref_symlink(struct ref_lock *lock, const char *target)
7bd9bcf3 2708{
370e5ad6 2709 int ret = -1;
7bd9bcf3 2710#ifndef NO_SYMLINK_HEAD
370e5ad6
JK
2711 char *ref_path = get_locked_file_path(lock->lk);
2712 unlink(ref_path);
2713 ret = symlink(target, ref_path);
2714 free(ref_path);
2715
2716 if (ret)
7bd9bcf3 2717 fprintf(stderr, "no symlink - falling back to symbolic ref\n");
7bd9bcf3 2718#endif
370e5ad6
JK
2719 return ret;
2720}
7bd9bcf3 2721
370e5ad6
JK
2722static void update_symref_reflog(struct ref_lock *lock, const char *refname,
2723 const char *target, const char *logmsg)
2724{
2725 struct strbuf err = STRBUF_INIT;
2726 unsigned char new_sha1[20];
b9badadd 2727 if (logmsg && !read_ref(target, new_sha1) &&
370e5ad6 2728 log_ref_write(refname, lock->old_oid.hash, new_sha1, logmsg, 0, &err)) {
7bd9bcf3
MH
2729 error("%s", err.buf);
2730 strbuf_release(&err);
2731 }
370e5ad6 2732}
7bd9bcf3 2733
370e5ad6
JK
2734static int create_symref_locked(struct ref_lock *lock, const char *refname,
2735 const char *target, const char *logmsg)
2736{
2737 if (prefer_symlink_refs && !create_ref_symlink(lock, target)) {
2738 update_symref_reflog(lock, refname, target, logmsg);
2739 return 0;
2740 }
2741
2742 if (!fdopen_lock_file(lock->lk, "w"))
2743 return error("unable to fdopen %s: %s",
2744 lock->lk->tempfile.filename.buf, strerror(errno));
2745
396da8f7
JK
2746 update_symref_reflog(lock, refname, target, logmsg);
2747
370e5ad6
JK
2748 /* no error check; commit_ref will check ferror */
2749 fprintf(lock->lk->tempfile.fp, "ref: %s\n", target);
2750 if (commit_ref(lock) < 0)
2751 return error("unable to write symref for %s: %s", refname,
2752 strerror(errno));
7bd9bcf3
MH
2753 return 0;
2754}
2755
370e5ad6
JK
2756int create_symref(const char *refname, const char *target, const char *logmsg)
2757{
2758 struct strbuf err = STRBUF_INIT;
2759 struct ref_lock *lock;
2760 int ret;
2761
2762 lock = lock_ref_sha1_basic(refname, NULL, NULL, NULL, REF_NODEREF, NULL,
2763 &err);
2764 if (!lock) {
2765 error("%s", err.buf);
2766 strbuf_release(&err);
2767 return -1;
2768 }
2769
2770 ret = create_symref_locked(lock, refname, target, logmsg);
2771 unlock_ref(lock);
2772 return ret;
2773}
2774
2233066e
KY
2775int set_worktree_head_symref(const char *gitdir, const char *target)
2776{
2777 static struct lock_file head_lock;
2778 struct ref_lock *lock;
2233066e
KY
2779 struct strbuf head_path = STRBUF_INIT;
2780 const char *head_rel;
2781 int ret;
2782
2783 strbuf_addf(&head_path, "%s/HEAD", absolute_path(gitdir));
2784 if (hold_lock_file_for_update(&head_lock, head_path.buf,
2785 LOCK_NO_DEREF) < 0) {
18eb3a9c
KY
2786 struct strbuf err = STRBUF_INIT;
2787 unable_to_lock_message(head_path.buf, errno, &err);
2233066e
KY
2788 error("%s", err.buf);
2789 strbuf_release(&err);
2790 strbuf_release(&head_path);
2791 return -1;
2792 }
2793
2794 /* head_rel will be "HEAD" for the main tree, "worktrees/wt/HEAD" for
2795 linked trees */
2796 head_rel = remove_leading_path(head_path.buf,
2797 absolute_path(get_git_common_dir()));
2798 /* to make use of create_symref_locked(), initialize ref_lock */
2799 lock = xcalloc(1, sizeof(struct ref_lock));
2800 lock->lk = &head_lock;
2801 lock->ref_name = xstrdup(head_rel);
2802 lock->orig_ref_name = xstrdup(head_rel);
2803
2804 ret = create_symref_locked(lock, head_rel, target, NULL);
2805
2806 unlock_ref(lock); /* will free lock */
2807 strbuf_release(&head_path);
2808 return ret;
2809}
2810
7bd9bcf3
MH
2811int reflog_exists(const char *refname)
2812{
2813 struct stat st;
2814
2815 return !lstat(git_path("logs/%s", refname), &st) &&
2816 S_ISREG(st.st_mode);
2817}
2818
2819int delete_reflog(const char *refname)
2820{
2821 return remove_path(git_path("logs/%s", refname));
2822}
2823
2824static int show_one_reflog_ent(struct strbuf *sb, each_reflog_ent_fn fn, void *cb_data)
2825{
2826 unsigned char osha1[20], nsha1[20];
2827 char *email_end, *message;
2828 unsigned long timestamp;
2829 int tz;
2830
2831 /* old SP new SP name <email> SP time TAB msg LF */
2832 if (sb->len < 83 || sb->buf[sb->len - 1] != '\n' ||
2833 get_sha1_hex(sb->buf, osha1) || sb->buf[40] != ' ' ||
2834 get_sha1_hex(sb->buf + 41, nsha1) || sb->buf[81] != ' ' ||
2835 !(email_end = strchr(sb->buf + 82, '>')) ||
2836 email_end[1] != ' ' ||
2837 !(timestamp = strtoul(email_end + 2, &message, 10)) ||
2838 !message || message[0] != ' ' ||
2839 (message[1] != '+' && message[1] != '-') ||
2840 !isdigit(message[2]) || !isdigit(message[3]) ||
2841 !isdigit(message[4]) || !isdigit(message[5]))
2842 return 0; /* corrupt? */
2843 email_end[1] = '\0';
2844 tz = strtol(message + 1, NULL, 10);
2845 if (message[6] != '\t')
2846 message += 6;
2847 else
2848 message += 7;
2849 return fn(osha1, nsha1, sb->buf + 82, timestamp, tz, message, cb_data);
2850}
2851
2852static char *find_beginning_of_line(char *bob, char *scan)
2853{
2854 while (bob < scan && *(--scan) != '\n')
2855 ; /* keep scanning backwards */
2856 /*
2857 * Return either beginning of the buffer, or LF at the end of
2858 * the previous line.
2859 */
2860 return scan;
2861}
2862
2863int for_each_reflog_ent_reverse(const char *refname, each_reflog_ent_fn fn, void *cb_data)
2864{
2865 struct strbuf sb = STRBUF_INIT;
2866 FILE *logfp;
2867 long pos;
2868 int ret = 0, at_tail = 1;
2869
2870 logfp = fopen(git_path("logs/%s", refname), "r");
2871 if (!logfp)
2872 return -1;
2873
2874 /* Jump to the end */
2875 if (fseek(logfp, 0, SEEK_END) < 0)
2876 return error("cannot seek back reflog for %s: %s",
2877 refname, strerror(errno));
2878 pos = ftell(logfp);
2879 while (!ret && 0 < pos) {
2880 int cnt;
2881 size_t nread;
2882 char buf[BUFSIZ];
2883 char *endp, *scanp;
2884
2885 /* Fill next block from the end */
2886 cnt = (sizeof(buf) < pos) ? sizeof(buf) : pos;
2887 if (fseek(logfp, pos - cnt, SEEK_SET))
2888 return error("cannot seek back reflog for %s: %s",
2889 refname, strerror(errno));
2890 nread = fread(buf, cnt, 1, logfp);
2891 if (nread != 1)
2892 return error("cannot read %d bytes from reflog for %s: %s",
2893 cnt, refname, strerror(errno));
2894 pos -= cnt;
2895
2896 scanp = endp = buf + cnt;
2897 if (at_tail && scanp[-1] == '\n')
2898 /* Looking at the final LF at the end of the file */
2899 scanp--;
2900 at_tail = 0;
2901
2902 while (buf < scanp) {
2903 /*
2904 * terminating LF of the previous line, or the beginning
2905 * of the buffer.
2906 */
2907 char *bp;
2908
2909 bp = find_beginning_of_line(buf, scanp);
2910
2911 if (*bp == '\n') {
2912 /*
2913 * The newline is the end of the previous line,
2914 * so we know we have complete line starting
2915 * at (bp + 1). Prefix it onto any prior data
2916 * we collected for the line and process it.
2917 */
2918 strbuf_splice(&sb, 0, 0, bp + 1, endp - (bp + 1));
2919 scanp = bp;
2920 endp = bp + 1;
2921 ret = show_one_reflog_ent(&sb, fn, cb_data);
2922 strbuf_reset(&sb);
2923 if (ret)
2924 break;
2925 } else if (!pos) {
2926 /*
2927 * We are at the start of the buffer, and the
2928 * start of the file; there is no previous
2929 * line, and we have everything for this one.
2930 * Process it, and we can end the loop.
2931 */
2932 strbuf_splice(&sb, 0, 0, buf, endp - buf);
2933 ret = show_one_reflog_ent(&sb, fn, cb_data);
2934 strbuf_reset(&sb);
2935 break;
2936 }
2937
2938 if (bp == buf) {
2939 /*
2940 * We are at the start of the buffer, and there
2941 * is more file to read backwards. Which means
2942 * we are in the middle of a line. Note that we
2943 * may get here even if *bp was a newline; that
2944 * just means we are at the exact end of the
2945 * previous line, rather than some spot in the
2946 * middle.
2947 *
2948 * Save away what we have to be combined with
2949 * the data from the next read.
2950 */
2951 strbuf_splice(&sb, 0, 0, buf, endp - buf);
2952 break;
2953 }
2954 }
2955
2956 }
2957 if (!ret && sb.len)
2958 die("BUG: reverse reflog parser had leftover data");
2959
2960 fclose(logfp);
2961 strbuf_release(&sb);
2962 return ret;
2963}
2964
2965int for_each_reflog_ent(const char *refname, each_reflog_ent_fn fn, void *cb_data)
2966{
2967 FILE *logfp;
2968 struct strbuf sb = STRBUF_INIT;
2969 int ret = 0;
2970
2971 logfp = fopen(git_path("logs/%s", refname), "r");
2972 if (!logfp)
2973 return -1;
2974
2975 while (!ret && !strbuf_getwholeline(&sb, logfp, '\n'))
2976 ret = show_one_reflog_ent(&sb, fn, cb_data);
2977 fclose(logfp);
2978 strbuf_release(&sb);
2979 return ret;
2980}
2981/*
2982 * Call fn for each reflog in the namespace indicated by name. name
2983 * must be empty or end with '/'. Name will be used as a scratch
2984 * space, but its contents will be restored before return.
2985 */
2986static int do_for_each_reflog(struct strbuf *name, each_ref_fn fn, void *cb_data)
2987{
2988 DIR *d = opendir(git_path("logs/%s", name->buf));
2989 int retval = 0;
2990 struct dirent *de;
2991 int oldlen = name->len;
2992
2993 if (!d)
2994 return name->len ? errno : 0;
2995
2996 while ((de = readdir(d)) != NULL) {
2997 struct stat st;
2998
2999 if (de->d_name[0] == '.')
3000 continue;
3001 if (ends_with(de->d_name, ".lock"))
3002 continue;
3003 strbuf_addstr(name, de->d_name);
3004 if (stat(git_path("logs/%s", name->buf), &st) < 0) {
3005 ; /* silently ignore */
3006 } else {
3007 if (S_ISDIR(st.st_mode)) {
3008 strbuf_addch(name, '/');
3009 retval = do_for_each_reflog(name, fn, cb_data);
3010 } else {
3011 struct object_id oid;
3012
3013 if (read_ref_full(name->buf, 0, oid.hash, NULL))
3014 retval = error("bad ref for %s", name->buf);
3015 else
3016 retval = fn(name->buf, &oid, 0, cb_data);
3017 }
3018 if (retval)
3019 break;
3020 }
3021 strbuf_setlen(name, oldlen);
3022 }
3023 closedir(d);
3024 return retval;
3025}
3026
3027int for_each_reflog(each_ref_fn fn, void *cb_data)
3028{
3029 int retval;
3030 struct strbuf name;
3031 strbuf_init(&name, PATH_MAX);
3032 retval = do_for_each_reflog(&name, fn, cb_data);
3033 strbuf_release(&name);
3034 return retval;
3035}
3036
3037static int ref_update_reject_duplicates(struct string_list *refnames,
3038 struct strbuf *err)
3039{
3040 int i, n = refnames->nr;
3041
3042 assert(err);
3043
3044 for (i = 1; i < n; i++)
3045 if (!strcmp(refnames->items[i - 1].string, refnames->items[i].string)) {
3046 strbuf_addf(err,
0568c8e9 3047 "multiple updates for ref '%s' not allowed.",
7bd9bcf3
MH
3048 refnames->items[i].string);
3049 return 1;
3050 }
3051 return 0;
3052}
3053
165056b2
MH
3054/*
3055 * Acquire all locks, verify old values if provided, check
3056 * that new values are valid, and write new values to the
3057 * lockfiles, ready to be activated. Only keep one lockfile
3058 * open at a time to avoid running out of file descriptors.
3059 */
3060static int lock_ref_for_update(struct ref_update *update,
3061 struct ref_transaction *transaction,
3062 struct string_list *affected_refnames,
3063 struct strbuf *err)
3064{
3065 int ret;
3066
3067 if ((update->flags & REF_HAVE_NEW) &&
3068 is_null_sha1(update->new_sha1))
3069 update->flags |= REF_DELETING;
3070 update->lock = lock_ref_sha1_basic(
3071 update->refname,
3072 ((update->flags & REF_HAVE_OLD) ?
3073 update->old_sha1 : NULL),
3074 affected_refnames, NULL,
3075 update->flags,
3076 &update->type,
3077 err);
3078 if (!update->lock) {
3079 char *reason;
3080
3081 ret = (errno == ENOTDIR)
3082 ? TRANSACTION_NAME_CONFLICT
3083 : TRANSACTION_GENERIC_ERROR;
3084 reason = strbuf_detach(err, NULL);
3085 strbuf_addf(err, "cannot lock ref '%s': %s",
3086 update->refname, reason);
3087 free(reason);
3088 return ret;
3089 }
3090 if ((update->flags & REF_HAVE_NEW) &&
3091 !(update->flags & REF_DELETING) &&
3092 !(update->flags & REF_LOG_ONLY)) {
3093 int overwriting_symref = ((update->type & REF_ISSYMREF) &&
3094 (update->flags & REF_NODEREF));
3095
3096 if (!overwriting_symref &&
3097 !hashcmp(update->lock->old_oid.hash, update->new_sha1)) {
3098 /*
3099 * The reference already has the desired
3100 * value, so we don't need to write it.
3101 */
3102 } else if (write_ref_to_lockfile(update->lock,
3103 update->new_sha1,
3104 err)) {
3105 char *write_err = strbuf_detach(err, NULL);
3106
3107 /*
3108 * The lock was freed upon failure of
3109 * write_ref_to_lockfile():
3110 */
3111 update->lock = NULL;
3112 strbuf_addf(err,
3113 "cannot update the ref '%s': %s",
3114 update->refname, write_err);
3115 free(write_err);
3116 return TRANSACTION_GENERIC_ERROR;
3117 } else {
3118 update->flags |= REF_NEEDS_COMMIT;
3119 }
3120 }
3121 if (!(update->flags & REF_NEEDS_COMMIT)) {
3122 /*
3123 * We didn't call write_ref_to_lockfile(), so
3124 * the lockfile is still open. Close it to
3125 * free up the file descriptor:
3126 */
3127 if (close_ref(update->lock)) {
3128 strbuf_addf(err, "couldn't close '%s.lock'",
3129 update->refname);
3130 return TRANSACTION_GENERIC_ERROR;
3131 }
3132 }
3133 return 0;
3134}
3135
7bd9bcf3
MH
3136int ref_transaction_commit(struct ref_transaction *transaction,
3137 struct strbuf *err)
3138{
3139 int ret = 0, i;
7bd9bcf3
MH
3140 struct string_list refs_to_delete = STRING_LIST_INIT_NODUP;
3141 struct string_list_item *ref_to_delete;
3142 struct string_list affected_refnames = STRING_LIST_INIT_NODUP;
3143
3144 assert(err);
3145
3146 if (transaction->state != REF_TRANSACTION_OPEN)
3147 die("BUG: commit called for transaction that is not open");
3148
efe47281 3149 if (!transaction->nr) {
7bd9bcf3
MH
3150 transaction->state = REF_TRANSACTION_CLOSED;
3151 return 0;
3152 }
3153
3154 /* Fail if a refname appears more than once in the transaction: */
efe47281
MH
3155 for (i = 0; i < transaction->nr; i++)
3156 string_list_append(&affected_refnames,
3157 transaction->updates[i]->refname);
7bd9bcf3
MH
3158 string_list_sort(&affected_refnames);
3159 if (ref_update_reject_duplicates(&affected_refnames, err)) {
3160 ret = TRANSACTION_GENERIC_ERROR;
3161 goto cleanup;
3162 }
3163
3164 /*
3165 * Acquire all locks, verify old values if provided, check
3166 * that new values are valid, and write new values to the
3167 * lockfiles, ready to be activated. Only keep one lockfile
3168 * open at a time to avoid running out of file descriptors.
3169 */
efe47281
MH
3170 for (i = 0; i < transaction->nr; i++) {
3171 struct ref_update *update = transaction->updates[i];
7bd9bcf3 3172
165056b2
MH
3173 ret = lock_ref_for_update(update, transaction,
3174 &affected_refnames, err);
3175 if (ret)
7bd9bcf3 3176 goto cleanup;
7bd9bcf3
MH
3177 }
3178
3179 /* Perform updates first so live commits remain referenced */
efe47281
MH
3180 for (i = 0; i < transaction->nr; i++) {
3181 struct ref_update *update = transaction->updates[i];
7bd9bcf3 3182
d99aa884
DT
3183 if (update->flags & REF_NEEDS_COMMIT ||
3184 update->flags & REF_LOG_ONLY) {
7bd9bcf3
MH
3185 if (commit_ref_update(update->lock,
3186 update->new_sha1, update->msg,
3187 update->flags, err)) {
3188 /* freed by commit_ref_update(): */
3189 update->lock = NULL;
3190 ret = TRANSACTION_GENERIC_ERROR;
3191 goto cleanup;
3192 } else {
3193 /* freed by commit_ref_update(): */
3194 update->lock = NULL;
3195 }
3196 }
3197 }
3198
3199 /* Perform deletes now that updates are safely completed */
efe47281
MH
3200 for (i = 0; i < transaction->nr; i++) {
3201 struct ref_update *update = transaction->updates[i];
7bd9bcf3 3202
d99aa884
DT
3203 if (update->flags & REF_DELETING &&
3204 !(update->flags & REF_LOG_ONLY)) {
7bd9bcf3
MH
3205 if (delete_ref_loose(update->lock, update->type, err)) {
3206 ret = TRANSACTION_GENERIC_ERROR;
3207 goto cleanup;
3208 }
3209
3210 if (!(update->flags & REF_ISPRUNING))
3211 string_list_append(&refs_to_delete,
3212 update->lock->ref_name);
3213 }
3214 }
3215
3216 if (repack_without_refs(&refs_to_delete, err)) {
3217 ret = TRANSACTION_GENERIC_ERROR;
3218 goto cleanup;
3219 }
3220 for_each_string_list_item(ref_to_delete, &refs_to_delete)
3221 unlink_or_warn(git_path("logs/%s", ref_to_delete->string));
3222 clear_loose_ref_cache(&ref_cache);
3223
3224cleanup:
3225 transaction->state = REF_TRANSACTION_CLOSED;
3226
efe47281
MH
3227 for (i = 0; i < transaction->nr; i++)
3228 if (transaction->updates[i]->lock)
3229 unlock_ref(transaction->updates[i]->lock);
7bd9bcf3
MH
3230 string_list_clear(&refs_to_delete, 0);
3231 string_list_clear(&affected_refnames, 0);
3232 return ret;
3233}
3234
3235static int ref_present(const char *refname,
3236 const struct object_id *oid, int flags, void *cb_data)
3237{
3238 struct string_list *affected_refnames = cb_data;
3239
3240 return string_list_has_string(affected_refnames, refname);
3241}
3242
3243int initial_ref_transaction_commit(struct ref_transaction *transaction,
3244 struct strbuf *err)
3245{
3246 int ret = 0, i;
7bd9bcf3
MH
3247 struct string_list affected_refnames = STRING_LIST_INIT_NODUP;
3248
3249 assert(err);
3250
3251 if (transaction->state != REF_TRANSACTION_OPEN)
3252 die("BUG: commit called for transaction that is not open");
3253
3254 /* Fail if a refname appears more than once in the transaction: */
efe47281
MH
3255 for (i = 0; i < transaction->nr; i++)
3256 string_list_append(&affected_refnames,
3257 transaction->updates[i]->refname);
7bd9bcf3
MH
3258 string_list_sort(&affected_refnames);
3259 if (ref_update_reject_duplicates(&affected_refnames, err)) {
3260 ret = TRANSACTION_GENERIC_ERROR;
3261 goto cleanup;
3262 }
3263
3264 /*
3265 * It's really undefined to call this function in an active
3266 * repository or when there are existing references: we are
3267 * only locking and changing packed-refs, so (1) any
3268 * simultaneous processes might try to change a reference at
3269 * the same time we do, and (2) any existing loose versions of
3270 * the references that we are setting would have precedence
3271 * over our values. But some remote helpers create the remote
3272 * "HEAD" and "master" branches before calling this function,
3273 * so here we really only check that none of the references
3274 * that we are creating already exists.
3275 */
3276 if (for_each_rawref(ref_present, &affected_refnames))
3277 die("BUG: initial ref transaction called with existing refs");
3278
efe47281
MH
3279 for (i = 0; i < transaction->nr; i++) {
3280 struct ref_update *update = transaction->updates[i];
7bd9bcf3
MH
3281
3282 if ((update->flags & REF_HAVE_OLD) &&
3283 !is_null_sha1(update->old_sha1))
3284 die("BUG: initial ref transaction with old_sha1 set");
3285 if (verify_refname_available(update->refname,
3286 &affected_refnames, NULL,
3287 err)) {
3288 ret = TRANSACTION_NAME_CONFLICT;
3289 goto cleanup;
3290 }
3291 }
3292
3293 if (lock_packed_refs(0)) {
3294 strbuf_addf(err, "unable to lock packed-refs file: %s",
3295 strerror(errno));
3296 ret = TRANSACTION_GENERIC_ERROR;
3297 goto cleanup;
3298 }
3299
efe47281
MH
3300 for (i = 0; i < transaction->nr; i++) {
3301 struct ref_update *update = transaction->updates[i];
7bd9bcf3
MH
3302
3303 if ((update->flags & REF_HAVE_NEW) &&
3304 !is_null_sha1(update->new_sha1))
3305 add_packed_ref(update->refname, update->new_sha1);
3306 }
3307
3308 if (commit_packed_refs()) {
3309 strbuf_addf(err, "unable to commit packed-refs file: %s",
3310 strerror(errno));
3311 ret = TRANSACTION_GENERIC_ERROR;
3312 goto cleanup;
3313 }
3314
3315cleanup:
3316 transaction->state = REF_TRANSACTION_CLOSED;
3317 string_list_clear(&affected_refnames, 0);
3318 return ret;
3319}
3320
3321struct expire_reflog_cb {
3322 unsigned int flags;
3323 reflog_expiry_should_prune_fn *should_prune_fn;
3324 void *policy_cb;
3325 FILE *newlog;
3326 unsigned char last_kept_sha1[20];
3327};
3328
3329static int expire_reflog_ent(unsigned char *osha1, unsigned char *nsha1,
3330 const char *email, unsigned long timestamp, int tz,
3331 const char *message, void *cb_data)
3332{
3333 struct expire_reflog_cb *cb = cb_data;
3334 struct expire_reflog_policy_cb *policy_cb = cb->policy_cb;
3335
3336 if (cb->flags & EXPIRE_REFLOGS_REWRITE)
3337 osha1 = cb->last_kept_sha1;
3338
3339 if ((*cb->should_prune_fn)(osha1, nsha1, email, timestamp, tz,
3340 message, policy_cb)) {
3341 if (!cb->newlog)
3342 printf("would prune %s", message);
3343 else if (cb->flags & EXPIRE_REFLOGS_VERBOSE)
3344 printf("prune %s", message);
3345 } else {
3346 if (cb->newlog) {
3347 fprintf(cb->newlog, "%s %s %s %lu %+05d\t%s",
3348 sha1_to_hex(osha1), sha1_to_hex(nsha1),
3349 email, timestamp, tz, message);
3350 hashcpy(cb->last_kept_sha1, nsha1);
3351 }
3352 if (cb->flags & EXPIRE_REFLOGS_VERBOSE)
3353 printf("keep %s", message);
3354 }
3355 return 0;
3356}
3357
3358int reflog_expire(const char *refname, const unsigned char *sha1,
3359 unsigned int flags,
3360 reflog_expiry_prepare_fn prepare_fn,
3361 reflog_expiry_should_prune_fn should_prune_fn,
3362 reflog_expiry_cleanup_fn cleanup_fn,
3363 void *policy_cb_data)
3364{
3365 static struct lock_file reflog_lock;
3366 struct expire_reflog_cb cb;
3367 struct ref_lock *lock;
3368 char *log_file;
3369 int status = 0;
3370 int type;
3371 struct strbuf err = STRBUF_INIT;
3372
3373 memset(&cb, 0, sizeof(cb));
3374 cb.flags = flags;
3375 cb.policy_cb = policy_cb_data;
3376 cb.should_prune_fn = should_prune_fn;
3377
3378 /*
3379 * The reflog file is locked by holding the lock on the
3380 * reference itself, plus we might need to update the
3381 * reference if --updateref was specified:
3382 */
41d796ed
DT
3383 lock = lock_ref_sha1_basic(refname, sha1, NULL, NULL, REF_NODEREF,
3384 &type, &err);
7bd9bcf3
MH
3385 if (!lock) {
3386 error("cannot lock ref '%s': %s", refname, err.buf);
3387 strbuf_release(&err);
3388 return -1;
3389 }
3390 if (!reflog_exists(refname)) {
3391 unlock_ref(lock);
3392 return 0;
3393 }
3394
3395 log_file = git_pathdup("logs/%s", refname);
3396 if (!(flags & EXPIRE_REFLOGS_DRY_RUN)) {
3397 /*
3398 * Even though holding $GIT_DIR/logs/$reflog.lock has
3399 * no locking implications, we use the lock_file
3400 * machinery here anyway because it does a lot of the
3401 * work we need, including cleaning up if the program
3402 * exits unexpectedly.
3403 */
3404 if (hold_lock_file_for_update(&reflog_lock, log_file, 0) < 0) {
3405 struct strbuf err = STRBUF_INIT;
3406 unable_to_lock_message(log_file, errno, &err);
3407 error("%s", err.buf);
3408 strbuf_release(&err);
3409 goto failure;
3410 }
3411 cb.newlog = fdopen_lock_file(&reflog_lock, "w");
3412 if (!cb.newlog) {
3413 error("cannot fdopen %s (%s)",
3414 get_lock_file_path(&reflog_lock), strerror(errno));
3415 goto failure;
3416 }
3417 }
3418
3419 (*prepare_fn)(refname, sha1, cb.policy_cb);
3420 for_each_reflog_ent(refname, expire_reflog_ent, &cb);
3421 (*cleanup_fn)(cb.policy_cb);
3422
3423 if (!(flags & EXPIRE_REFLOGS_DRY_RUN)) {
3424 /*
3425 * It doesn't make sense to adjust a reference pointed
3426 * to by a symbolic ref based on expiring entries in
3427 * the symbolic reference's reflog. Nor can we update
3428 * a reference if there are no remaining reflog
3429 * entries.
3430 */
3431 int update = (flags & EXPIRE_REFLOGS_UPDATE_REF) &&
3432 !(type & REF_ISSYMREF) &&
3433 !is_null_sha1(cb.last_kept_sha1);
3434
3435 if (close_lock_file(&reflog_lock)) {
3436 status |= error("couldn't write %s: %s", log_file,
3437 strerror(errno));
3438 } else if (update &&
3439 (write_in_full(get_lock_file_fd(lock->lk),
3440 sha1_to_hex(cb.last_kept_sha1), 40) != 40 ||
3441 write_str_in_full(get_lock_file_fd(lock->lk), "\n") != 1 ||
3442 close_ref(lock) < 0)) {
3443 status |= error("couldn't write %s",
3444 get_lock_file_path(lock->lk));
3445 rollback_lock_file(&reflog_lock);
3446 } else if (commit_lock_file(&reflog_lock)) {
e0048d3e 3447 status |= error("unable to write reflog '%s' (%s)",
7bd9bcf3
MH
3448 log_file, strerror(errno));
3449 } else if (update && commit_ref(lock)) {
3450 status |= error("couldn't set %s", lock->ref_name);
3451 }
3452 }
3453 free(log_file);
3454 unlock_ref(lock);
3455 return status;
3456
3457 failure:
3458 rollback_lock_file(&reflog_lock);
3459 free(log_file);
3460 unlock_ref(lock);
3461 return -1;
3462}