lockfile.h: extract new header file for the functions in lockfile.c
[git/git.git] / refs.c
1 #include "cache.h"
2 #include "lockfile.h"
3 #include "refs.h"
4 #include "object.h"
5 #include "tag.h"
6 #include "dir.h"
7 #include "string-list.h"
8
9 /*
10 * How to handle various characters in refnames:
11 * 0: An acceptable character for refs
12 * 1: End-of-component
13 * 2: ., look for a preceding . to reject .. in refs
14 * 3: {, look for a preceding @ to reject @{ in refs
15 * 4: A bad character: ASCII control characters, "~", "^", ":" or SP
16 */
17 static unsigned char refname_disposition[256] = {
18 1, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
19 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
20 4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4, 0, 0, 0, 2, 1,
21 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4, 0, 0, 0, 0, 4,
22 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
23 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4, 4, 0, 4, 0,
24 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
25 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 3, 0, 0, 4, 4
26 };
27
28 /*
29 * Used as a flag to ref_transaction_delete when a loose ref is being
30 * pruned.
31 */
32 #define REF_ISPRUNING 0x0100
33 /*
34 * Try to read one refname component from the front of refname.
35 * Return the length of the component found, or -1 if the component is
36 * not legal. It is legal if it is something reasonable to have under
37 * ".git/refs/"; We do not like it if:
38 *
39 * - any path component of it begins with ".", or
40 * - it has double dots "..", or
41 * - it has ASCII control character, "~", "^", ":" or SP, anywhere, or
42 * - it ends with a "/".
43 * - it ends with ".lock"
44 * - it contains a "\" (backslash)
45 */
46 static int check_refname_component(const char *refname, int flags)
47 {
48 const char *cp;
49 char last = '\0';
50
51 for (cp = refname; ; cp++) {
52 int ch = *cp & 255;
53 unsigned char disp = refname_disposition[ch];
54 switch (disp) {
55 case 1:
56 goto out;
57 case 2:
58 if (last == '.')
59 return -1; /* Refname contains "..". */
60 break;
61 case 3:
62 if (last == '@')
63 return -1; /* Refname contains "@{". */
64 break;
65 case 4:
66 return -1;
67 }
68 last = ch;
69 }
70 out:
71 if (cp == refname)
72 return 0; /* Component has zero length. */
73 if (refname[0] == '.') {
74 if (!(flags & REFNAME_DOT_COMPONENT))
75 return -1; /* Component starts with '.'. */
76 /*
77 * Even if leading dots are allowed, don't allow "."
78 * as a component (".." is prevented by a rule above).
79 */
80 if (refname[1] == '\0')
81 return -1; /* Component equals ".". */
82 }
83 if (cp - refname >= LOCK_SUFFIX_LEN &&
84 !memcmp(cp - LOCK_SUFFIX_LEN, LOCK_SUFFIX, LOCK_SUFFIX_LEN))
85 return -1; /* Refname ends with ".lock". */
86 return cp - refname;
87 }
88
89 int check_refname_format(const char *refname, int flags)
90 {
91 int component_len, component_count = 0;
92
93 if (!strcmp(refname, "@"))
94 /* Refname is a single character '@'. */
95 return -1;
96
97 while (1) {
98 /* We are at the start of a path component. */
99 component_len = check_refname_component(refname, flags);
100 if (component_len <= 0) {
101 if ((flags & REFNAME_REFSPEC_PATTERN) &&
102 refname[0] == '*' &&
103 (refname[1] == '\0' || refname[1] == '/')) {
104 /* Accept one wildcard as a full refname component. */
105 flags &= ~REFNAME_REFSPEC_PATTERN;
106 component_len = 1;
107 } else {
108 return -1;
109 }
110 }
111 component_count++;
112 if (refname[component_len] == '\0')
113 break;
114 /* Skip to next component. */
115 refname += component_len + 1;
116 }
117
118 if (refname[component_len - 1] == '.')
119 return -1; /* Refname ends with '.'. */
120 if (!(flags & REFNAME_ALLOW_ONELEVEL) && component_count < 2)
121 return -1; /* Refname has only one component. */
122 return 0;
123 }
124
125 struct ref_entry;
126
127 /*
128 * Information used (along with the information in ref_entry) to
129 * describe a single cached reference. This data structure only
130 * occurs embedded in a union in struct ref_entry, and only when
131 * (ref_entry->flag & REF_DIR) is zero.
132 */
133 struct ref_value {
134 /*
135 * The name of the object to which this reference resolves
136 * (which may be a tag object). If REF_ISBROKEN, this is
137 * null. If REF_ISSYMREF, then this is the name of the object
138 * referred to by the last reference in the symlink chain.
139 */
140 unsigned char sha1[20];
141
142 /*
143 * If REF_KNOWS_PEELED, then this field holds the peeled value
144 * of this reference, or null if the reference is known not to
145 * be peelable. See the documentation for peel_ref() for an
146 * exact definition of "peelable".
147 */
148 unsigned char peeled[20];
149 };
150
151 struct ref_cache;
152
153 /*
154 * Information used (along with the information in ref_entry) to
155 * describe a level in the hierarchy of references. This data
156 * structure only occurs embedded in a union in struct ref_entry, and
157 * only when (ref_entry.flag & REF_DIR) is set. In that case,
158 * (ref_entry.flag & REF_INCOMPLETE) determines whether the references
159 * in the directory have already been read:
160 *
161 * (ref_entry.flag & REF_INCOMPLETE) unset -- a directory of loose
162 * or packed references, already read.
163 *
164 * (ref_entry.flag & REF_INCOMPLETE) set -- a directory of loose
165 * references that hasn't been read yet (nor has any of its
166 * subdirectories).
167 *
168 * Entries within a directory are stored within a growable array of
169 * pointers to ref_entries (entries, nr, alloc). Entries 0 <= i <
170 * sorted are sorted by their component name in strcmp() order and the
171 * remaining entries are unsorted.
172 *
173 * Loose references are read lazily, one directory at a time. When a
174 * directory of loose references is read, then all of the references
175 * in that directory are stored, and REF_INCOMPLETE stubs are created
176 * for any subdirectories, but the subdirectories themselves are not
177 * read. The reading is triggered by get_ref_dir().
178 */
179 struct ref_dir {
180 int nr, alloc;
181
182 /*
183 * Entries with index 0 <= i < sorted are sorted by name. New
184 * entries are appended to the list unsorted, and are sorted
185 * only when required; thus we avoid the need to sort the list
186 * after the addition of every reference.
187 */
188 int sorted;
189
190 /* A pointer to the ref_cache that contains this ref_dir. */
191 struct ref_cache *ref_cache;
192
193 struct ref_entry **entries;
194 };
195
196 /*
197 * Bit values for ref_entry::flag. REF_ISSYMREF=0x01,
198 * REF_ISPACKED=0x02, and REF_ISBROKEN=0x04 are public values; see
199 * refs.h.
200 */
201
202 /*
203 * The field ref_entry->u.value.peeled of this value entry contains
204 * the correct peeled value for the reference, which might be
205 * null_sha1 if the reference is not a tag or if it is broken.
206 */
207 #define REF_KNOWS_PEELED 0x08
208
209 /* ref_entry represents a directory of references */
210 #define REF_DIR 0x10
211
212 /*
213 * Entry has not yet been read from disk (used only for REF_DIR
214 * entries representing loose references)
215 */
216 #define REF_INCOMPLETE 0x20
217
218 /*
219 * A ref_entry represents either a reference or a "subdirectory" of
220 * references.
221 *
222 * Each directory in the reference namespace is represented by a
223 * ref_entry with (flags & REF_DIR) set and containing a subdir member
224 * that holds the entries in that directory that have been read so
225 * far. If (flags & REF_INCOMPLETE) is set, then the directory and
226 * its subdirectories haven't been read yet. REF_INCOMPLETE is only
227 * used for loose reference directories.
228 *
229 * References are represented by a ref_entry with (flags & REF_DIR)
230 * unset and a value member that describes the reference's value. The
231 * flag member is at the ref_entry level, but it is also needed to
232 * interpret the contents of the value field (in other words, a
233 * ref_value object is not very much use without the enclosing
234 * ref_entry).
235 *
236 * Reference names cannot end with slash and directories' names are
237 * always stored with a trailing slash (except for the top-level
238 * directory, which is always denoted by ""). This has two nice
239 * consequences: (1) when the entries in each subdir are sorted
240 * lexicographically by name (as they usually are), the references in
241 * a whole tree can be generated in lexicographic order by traversing
242 * the tree in left-to-right, depth-first order; (2) the names of
243 * references and subdirectories cannot conflict, and therefore the
244 * presence of an empty subdirectory does not block the creation of a
245 * similarly-named reference. (The fact that reference names with the
246 * same leading components can conflict *with each other* is a
247 * separate issue that is regulated by is_refname_available().)
248 *
249 * Please note that the name field contains the fully-qualified
250 * reference (or subdirectory) name. Space could be saved by only
251 * storing the relative names. But that would require the full names
252 * to be generated on the fly when iterating in do_for_each_ref(), and
253 * would break callback functions, who have always been able to assume
254 * that the name strings that they are passed will not be freed during
255 * the iteration.
256 */
257 struct ref_entry {
258 unsigned char flag; /* ISSYMREF? ISPACKED? */
259 union {
260 struct ref_value value; /* if not (flags&REF_DIR) */
261 struct ref_dir subdir; /* if (flags&REF_DIR) */
262 } u;
263 /*
264 * The full name of the reference (e.g., "refs/heads/master")
265 * or the full name of the directory with a trailing slash
266 * (e.g., "refs/heads/"):
267 */
268 char name[FLEX_ARRAY];
269 };
270
271 static void read_loose_refs(const char *dirname, struct ref_dir *dir);
272
273 static struct ref_dir *get_ref_dir(struct ref_entry *entry)
274 {
275 struct ref_dir *dir;
276 assert(entry->flag & REF_DIR);
277 dir = &entry->u.subdir;
278 if (entry->flag & REF_INCOMPLETE) {
279 read_loose_refs(entry->name, dir);
280 entry->flag &= ~REF_INCOMPLETE;
281 }
282 return dir;
283 }
284
285 static struct ref_entry *create_ref_entry(const char *refname,
286 const unsigned char *sha1, int flag,
287 int check_name)
288 {
289 int len;
290 struct ref_entry *ref;
291
292 if (check_name &&
293 check_refname_format(refname, REFNAME_ALLOW_ONELEVEL|REFNAME_DOT_COMPONENT))
294 die("Reference has invalid format: '%s'", refname);
295 len = strlen(refname) + 1;
296 ref = xmalloc(sizeof(struct ref_entry) + len);
297 hashcpy(ref->u.value.sha1, sha1);
298 hashclr(ref->u.value.peeled);
299 memcpy(ref->name, refname, len);
300 ref->flag = flag;
301 return ref;
302 }
303
304 static void clear_ref_dir(struct ref_dir *dir);
305
306 static void free_ref_entry(struct ref_entry *entry)
307 {
308 if (entry->flag & REF_DIR) {
309 /*
310 * Do not use get_ref_dir() here, as that might
311 * trigger the reading of loose refs.
312 */
313 clear_ref_dir(&entry->u.subdir);
314 }
315 free(entry);
316 }
317
318 /*
319 * Add a ref_entry to the end of dir (unsorted). Entry is always
320 * stored directly in dir; no recursion into subdirectories is
321 * done.
322 */
323 static void add_entry_to_dir(struct ref_dir *dir, struct ref_entry *entry)
324 {
325 ALLOC_GROW(dir->entries, dir->nr + 1, dir->alloc);
326 dir->entries[dir->nr++] = entry;
327 /* optimize for the case that entries are added in order */
328 if (dir->nr == 1 ||
329 (dir->nr == dir->sorted + 1 &&
330 strcmp(dir->entries[dir->nr - 2]->name,
331 dir->entries[dir->nr - 1]->name) < 0))
332 dir->sorted = dir->nr;
333 }
334
335 /*
336 * Clear and free all entries in dir, recursively.
337 */
338 static void clear_ref_dir(struct ref_dir *dir)
339 {
340 int i;
341 for (i = 0; i < dir->nr; i++)
342 free_ref_entry(dir->entries[i]);
343 free(dir->entries);
344 dir->sorted = dir->nr = dir->alloc = 0;
345 dir->entries = NULL;
346 }
347
348 /*
349 * Create a struct ref_entry object for the specified dirname.
350 * dirname is the name of the directory with a trailing slash (e.g.,
351 * "refs/heads/") or "" for the top-level directory.
352 */
353 static struct ref_entry *create_dir_entry(struct ref_cache *ref_cache,
354 const char *dirname, size_t len,
355 int incomplete)
356 {
357 struct ref_entry *direntry;
358 direntry = xcalloc(1, sizeof(struct ref_entry) + len + 1);
359 memcpy(direntry->name, dirname, len);
360 direntry->name[len] = '\0';
361 direntry->u.subdir.ref_cache = ref_cache;
362 direntry->flag = REF_DIR | (incomplete ? REF_INCOMPLETE : 0);
363 return direntry;
364 }
365
366 static int ref_entry_cmp(const void *a, const void *b)
367 {
368 struct ref_entry *one = *(struct ref_entry **)a;
369 struct ref_entry *two = *(struct ref_entry **)b;
370 return strcmp(one->name, two->name);
371 }
372
373 static void sort_ref_dir(struct ref_dir *dir);
374
375 struct string_slice {
376 size_t len;
377 const char *str;
378 };
379
380 static int ref_entry_cmp_sslice(const void *key_, const void *ent_)
381 {
382 const struct string_slice *key = key_;
383 const struct ref_entry *ent = *(const struct ref_entry * const *)ent_;
384 int cmp = strncmp(key->str, ent->name, key->len);
385 if (cmp)
386 return cmp;
387 return '\0' - (unsigned char)ent->name[key->len];
388 }
389
390 /*
391 * Return the index of the entry with the given refname from the
392 * ref_dir (non-recursively), sorting dir if necessary. Return -1 if
393 * no such entry is found. dir must already be complete.
394 */
395 static int search_ref_dir(struct ref_dir *dir, const char *refname, size_t len)
396 {
397 struct ref_entry **r;
398 struct string_slice key;
399
400 if (refname == NULL || !dir->nr)
401 return -1;
402
403 sort_ref_dir(dir);
404 key.len = len;
405 key.str = refname;
406 r = bsearch(&key, dir->entries, dir->nr, sizeof(*dir->entries),
407 ref_entry_cmp_sslice);
408
409 if (r == NULL)
410 return -1;
411
412 return r - dir->entries;
413 }
414
415 /*
416 * Search for a directory entry directly within dir (without
417 * recursing). Sort dir if necessary. subdirname must be a directory
418 * name (i.e., end in '/'). If mkdir is set, then create the
419 * directory if it is missing; otherwise, return NULL if the desired
420 * directory cannot be found. dir must already be complete.
421 */
422 static struct ref_dir *search_for_subdir(struct ref_dir *dir,
423 const char *subdirname, size_t len,
424 int mkdir)
425 {
426 int entry_index = search_ref_dir(dir, subdirname, len);
427 struct ref_entry *entry;
428 if (entry_index == -1) {
429 if (!mkdir)
430 return NULL;
431 /*
432 * Since dir is complete, the absence of a subdir
433 * means that the subdir really doesn't exist;
434 * therefore, create an empty record for it but mark
435 * the record complete.
436 */
437 entry = create_dir_entry(dir->ref_cache, subdirname, len, 0);
438 add_entry_to_dir(dir, entry);
439 } else {
440 entry = dir->entries[entry_index];
441 }
442 return get_ref_dir(entry);
443 }
444
445 /*
446 * If refname is a reference name, find the ref_dir within the dir
447 * tree that should hold refname. If refname is a directory name
448 * (i.e., ends in '/'), then return that ref_dir itself. dir must
449 * represent the top-level directory and must already be complete.
450 * Sort ref_dirs and recurse into subdirectories as necessary. If
451 * mkdir is set, then create any missing directories; otherwise,
452 * return NULL if the desired directory cannot be found.
453 */
454 static struct ref_dir *find_containing_dir(struct ref_dir *dir,
455 const char *refname, int mkdir)
456 {
457 const char *slash;
458 for (slash = strchr(refname, '/'); slash; slash = strchr(slash + 1, '/')) {
459 size_t dirnamelen = slash - refname + 1;
460 struct ref_dir *subdir;
461 subdir = search_for_subdir(dir, refname, dirnamelen, mkdir);
462 if (!subdir) {
463 dir = NULL;
464 break;
465 }
466 dir = subdir;
467 }
468
469 return dir;
470 }
471
472 /*
473 * Find the value entry with the given name in dir, sorting ref_dirs
474 * and recursing into subdirectories as necessary. If the name is not
475 * found or it corresponds to a directory entry, return NULL.
476 */
477 static struct ref_entry *find_ref(struct ref_dir *dir, const char *refname)
478 {
479 int entry_index;
480 struct ref_entry *entry;
481 dir = find_containing_dir(dir, refname, 0);
482 if (!dir)
483 return NULL;
484 entry_index = search_ref_dir(dir, refname, strlen(refname));
485 if (entry_index == -1)
486 return NULL;
487 entry = dir->entries[entry_index];
488 return (entry->flag & REF_DIR) ? NULL : entry;
489 }
490
491 /*
492 * Remove the entry with the given name from dir, recursing into
493 * subdirectories as necessary. If refname is the name of a directory
494 * (i.e., ends with '/'), then remove the directory and its contents.
495 * If the removal was successful, return the number of entries
496 * remaining in the directory entry that contained the deleted entry.
497 * If the name was not found, return -1. Please note that this
498 * function only deletes the entry from the cache; it does not delete
499 * it from the filesystem or ensure that other cache entries (which
500 * might be symbolic references to the removed entry) are updated.
501 * Nor does it remove any containing dir entries that might be made
502 * empty by the removal. dir must represent the top-level directory
503 * and must already be complete.
504 */
505 static int remove_entry(struct ref_dir *dir, const char *refname)
506 {
507 int refname_len = strlen(refname);
508 int entry_index;
509 struct ref_entry *entry;
510 int is_dir = refname[refname_len - 1] == '/';
511 if (is_dir) {
512 /*
513 * refname represents a reference directory. Remove
514 * the trailing slash; otherwise we will get the
515 * directory *representing* refname rather than the
516 * one *containing* it.
517 */
518 char *dirname = xmemdupz(refname, refname_len - 1);
519 dir = find_containing_dir(dir, dirname, 0);
520 free(dirname);
521 } else {
522 dir = find_containing_dir(dir, refname, 0);
523 }
524 if (!dir)
525 return -1;
526 entry_index = search_ref_dir(dir, refname, refname_len);
527 if (entry_index == -1)
528 return -1;
529 entry = dir->entries[entry_index];
530
531 memmove(&dir->entries[entry_index],
532 &dir->entries[entry_index + 1],
533 (dir->nr - entry_index - 1) * sizeof(*dir->entries)
534 );
535 dir->nr--;
536 if (dir->sorted > entry_index)
537 dir->sorted--;
538 free_ref_entry(entry);
539 return dir->nr;
540 }
541
542 /*
543 * Add a ref_entry to the ref_dir (unsorted), recursing into
544 * subdirectories as necessary. dir must represent the top-level
545 * directory. Return 0 on success.
546 */
547 static int add_ref(struct ref_dir *dir, struct ref_entry *ref)
548 {
549 dir = find_containing_dir(dir, ref->name, 1);
550 if (!dir)
551 return -1;
552 add_entry_to_dir(dir, ref);
553 return 0;
554 }
555
556 /*
557 * Emit a warning and return true iff ref1 and ref2 have the same name
558 * and the same sha1. Die if they have the same name but different
559 * sha1s.
560 */
561 static int is_dup_ref(const struct ref_entry *ref1, const struct ref_entry *ref2)
562 {
563 if (strcmp(ref1->name, ref2->name))
564 return 0;
565
566 /* Duplicate name; make sure that they don't conflict: */
567
568 if ((ref1->flag & REF_DIR) || (ref2->flag & REF_DIR))
569 /* This is impossible by construction */
570 die("Reference directory conflict: %s", ref1->name);
571
572 if (hashcmp(ref1->u.value.sha1, ref2->u.value.sha1))
573 die("Duplicated ref, and SHA1s don't match: %s", ref1->name);
574
575 warning("Duplicated ref: %s", ref1->name);
576 return 1;
577 }
578
579 /*
580 * Sort the entries in dir non-recursively (if they are not already
581 * sorted) and remove any duplicate entries.
582 */
583 static void sort_ref_dir(struct ref_dir *dir)
584 {
585 int i, j;
586 struct ref_entry *last = NULL;
587
588 /*
589 * This check also prevents passing a zero-length array to qsort(),
590 * which is a problem on some platforms.
591 */
592 if (dir->sorted == dir->nr)
593 return;
594
595 qsort(dir->entries, dir->nr, sizeof(*dir->entries), ref_entry_cmp);
596
597 /* Remove any duplicates: */
598 for (i = 0, j = 0; j < dir->nr; j++) {
599 struct ref_entry *entry = dir->entries[j];
600 if (last && is_dup_ref(last, entry))
601 free_ref_entry(entry);
602 else
603 last = dir->entries[i++] = entry;
604 }
605 dir->sorted = dir->nr = i;
606 }
607
608 /* Include broken references in a do_for_each_ref*() iteration: */
609 #define DO_FOR_EACH_INCLUDE_BROKEN 0x01
610
611 /*
612 * Return true iff the reference described by entry can be resolved to
613 * an object in the database. Emit a warning if the referred-to
614 * object does not exist.
615 */
616 static int ref_resolves_to_object(struct ref_entry *entry)
617 {
618 if (entry->flag & REF_ISBROKEN)
619 return 0;
620 if (!has_sha1_file(entry->u.value.sha1)) {
621 error("%s does not point to a valid object!", entry->name);
622 return 0;
623 }
624 return 1;
625 }
626
627 /*
628 * current_ref is a performance hack: when iterating over references
629 * using the for_each_ref*() functions, current_ref is set to the
630 * current reference's entry before calling the callback function. If
631 * the callback function calls peel_ref(), then peel_ref() first
632 * checks whether the reference to be peeled is the current reference
633 * (it usually is) and if so, returns that reference's peeled version
634 * if it is available. This avoids a refname lookup in a common case.
635 */
636 static struct ref_entry *current_ref;
637
638 typedef int each_ref_entry_fn(struct ref_entry *entry, void *cb_data);
639
640 struct ref_entry_cb {
641 const char *base;
642 int trim;
643 int flags;
644 each_ref_fn *fn;
645 void *cb_data;
646 };
647
648 /*
649 * Handle one reference in a do_for_each_ref*()-style iteration,
650 * calling an each_ref_fn for each entry.
651 */
652 static int do_one_ref(struct ref_entry *entry, void *cb_data)
653 {
654 struct ref_entry_cb *data = cb_data;
655 struct ref_entry *old_current_ref;
656 int retval;
657
658 if (!starts_with(entry->name, data->base))
659 return 0;
660
661 if (!(data->flags & DO_FOR_EACH_INCLUDE_BROKEN) &&
662 !ref_resolves_to_object(entry))
663 return 0;
664
665 /* Store the old value, in case this is a recursive call: */
666 old_current_ref = current_ref;
667 current_ref = entry;
668 retval = data->fn(entry->name + data->trim, entry->u.value.sha1,
669 entry->flag, data->cb_data);
670 current_ref = old_current_ref;
671 return retval;
672 }
673
674 /*
675 * Call fn for each reference in dir that has index in the range
676 * offset <= index < dir->nr. Recurse into subdirectories that are in
677 * that index range, sorting them before iterating. This function
678 * does not sort dir itself; it should be sorted beforehand. fn is
679 * called for all references, including broken ones.
680 */
681 static int do_for_each_entry_in_dir(struct ref_dir *dir, int offset,
682 each_ref_entry_fn fn, void *cb_data)
683 {
684 int i;
685 assert(dir->sorted == dir->nr);
686 for (i = offset; i < dir->nr; i++) {
687 struct ref_entry *entry = dir->entries[i];
688 int retval;
689 if (entry->flag & REF_DIR) {
690 struct ref_dir *subdir = get_ref_dir(entry);
691 sort_ref_dir(subdir);
692 retval = do_for_each_entry_in_dir(subdir, 0, fn, cb_data);
693 } else {
694 retval = fn(entry, cb_data);
695 }
696 if (retval)
697 return retval;
698 }
699 return 0;
700 }
701
702 /*
703 * Call fn for each reference in the union of dir1 and dir2, in order
704 * by refname. Recurse into subdirectories. If a value entry appears
705 * in both dir1 and dir2, then only process the version that is in
706 * dir2. The input dirs must already be sorted, but subdirs will be
707 * sorted as needed. fn is called for all references, including
708 * broken ones.
709 */
710 static int do_for_each_entry_in_dirs(struct ref_dir *dir1,
711 struct ref_dir *dir2,
712 each_ref_entry_fn fn, void *cb_data)
713 {
714 int retval;
715 int i1 = 0, i2 = 0;
716
717 assert(dir1->sorted == dir1->nr);
718 assert(dir2->sorted == dir2->nr);
719 while (1) {
720 struct ref_entry *e1, *e2;
721 int cmp;
722 if (i1 == dir1->nr) {
723 return do_for_each_entry_in_dir(dir2, i2, fn, cb_data);
724 }
725 if (i2 == dir2->nr) {
726 return do_for_each_entry_in_dir(dir1, i1, fn, cb_data);
727 }
728 e1 = dir1->entries[i1];
729 e2 = dir2->entries[i2];
730 cmp = strcmp(e1->name, e2->name);
731 if (cmp == 0) {
732 if ((e1->flag & REF_DIR) && (e2->flag & REF_DIR)) {
733 /* Both are directories; descend them in parallel. */
734 struct ref_dir *subdir1 = get_ref_dir(e1);
735 struct ref_dir *subdir2 = get_ref_dir(e2);
736 sort_ref_dir(subdir1);
737 sort_ref_dir(subdir2);
738 retval = do_for_each_entry_in_dirs(
739 subdir1, subdir2, fn, cb_data);
740 i1++;
741 i2++;
742 } else if (!(e1->flag & REF_DIR) && !(e2->flag & REF_DIR)) {
743 /* Both are references; ignore the one from dir1. */
744 retval = fn(e2, cb_data);
745 i1++;
746 i2++;
747 } else {
748 die("conflict between reference and directory: %s",
749 e1->name);
750 }
751 } else {
752 struct ref_entry *e;
753 if (cmp < 0) {
754 e = e1;
755 i1++;
756 } else {
757 e = e2;
758 i2++;
759 }
760 if (e->flag & REF_DIR) {
761 struct ref_dir *subdir = get_ref_dir(e);
762 sort_ref_dir(subdir);
763 retval = do_for_each_entry_in_dir(
764 subdir, 0, fn, cb_data);
765 } else {
766 retval = fn(e, cb_data);
767 }
768 }
769 if (retval)
770 return retval;
771 }
772 }
773
774 /*
775 * Load all of the refs from the dir into our in-memory cache. The hard work
776 * of loading loose refs is done by get_ref_dir(), so we just need to recurse
777 * through all of the sub-directories. We do not even need to care about
778 * sorting, as traversal order does not matter to us.
779 */
780 static void prime_ref_dir(struct ref_dir *dir)
781 {
782 int i;
783 for (i = 0; i < dir->nr; i++) {
784 struct ref_entry *entry = dir->entries[i];
785 if (entry->flag & REF_DIR)
786 prime_ref_dir(get_ref_dir(entry));
787 }
788 }
789
790 static int entry_matches(struct ref_entry *entry, const char *refname)
791 {
792 return refname && !strcmp(entry->name, refname);
793 }
794
795 struct nonmatching_ref_data {
796 const char *skip;
797 struct ref_entry *found;
798 };
799
800 static int nonmatching_ref_fn(struct ref_entry *entry, void *vdata)
801 {
802 struct nonmatching_ref_data *data = vdata;
803
804 if (entry_matches(entry, data->skip))
805 return 0;
806
807 data->found = entry;
808 return 1;
809 }
810
811 static void report_refname_conflict(struct ref_entry *entry,
812 const char *refname)
813 {
814 error("'%s' exists; cannot create '%s'", entry->name, refname);
815 }
816
817 /*
818 * Return true iff a reference named refname could be created without
819 * conflicting with the name of an existing reference in dir. If
820 * oldrefname is non-NULL, ignore potential conflicts with oldrefname
821 * (e.g., because oldrefname is scheduled for deletion in the same
822 * operation).
823 *
824 * Two reference names conflict if one of them exactly matches the
825 * leading components of the other; e.g., "foo/bar" conflicts with
826 * both "foo" and with "foo/bar/baz" but not with "foo/bar" or
827 * "foo/barbados".
828 */
829 static int is_refname_available(const char *refname, const char *oldrefname,
830 struct ref_dir *dir)
831 {
832 const char *slash;
833 size_t len;
834 int pos;
835 char *dirname;
836
837 for (slash = strchr(refname, '/'); slash; slash = strchr(slash + 1, '/')) {
838 /*
839 * We are still at a leading dir of the refname; we are
840 * looking for a conflict with a leaf entry.
841 *
842 * If we find one, we still must make sure it is
843 * not "oldrefname".
844 */
845 pos = search_ref_dir(dir, refname, slash - refname);
846 if (pos >= 0) {
847 struct ref_entry *entry = dir->entries[pos];
848 if (entry_matches(entry, oldrefname))
849 return 1;
850 report_refname_conflict(entry, refname);
851 return 0;
852 }
853
854
855 /*
856 * Otherwise, we can try to continue our search with
857 * the next component; if we come up empty, we know
858 * there is nothing under this whole prefix.
859 */
860 pos = search_ref_dir(dir, refname, slash + 1 - refname);
861 if (pos < 0)
862 return 1;
863
864 dir = get_ref_dir(dir->entries[pos]);
865 }
866
867 /*
868 * We are at the leaf of our refname; we want to
869 * make sure there are no directories which match it.
870 */
871 len = strlen(refname);
872 dirname = xmallocz(len + 1);
873 sprintf(dirname, "%s/", refname);
874 pos = search_ref_dir(dir, dirname, len + 1);
875 free(dirname);
876
877 if (pos >= 0) {
878 /*
879 * We found a directory named "refname". It is a
880 * problem iff it contains any ref that is not
881 * "oldrefname".
882 */
883 struct ref_entry *entry = dir->entries[pos];
884 struct ref_dir *dir = get_ref_dir(entry);
885 struct nonmatching_ref_data data;
886
887 data.skip = oldrefname;
888 sort_ref_dir(dir);
889 if (!do_for_each_entry_in_dir(dir, 0, nonmatching_ref_fn, &data))
890 return 1;
891
892 report_refname_conflict(data.found, refname);
893 return 0;
894 }
895
896 /*
897 * There is no point in searching for another leaf
898 * node which matches it; such an entry would be the
899 * ref we are looking for, not a conflict.
900 */
901 return 1;
902 }
903
904 struct packed_ref_cache {
905 struct ref_entry *root;
906
907 /*
908 * Count of references to the data structure in this instance,
909 * including the pointer from ref_cache::packed if any. The
910 * data will not be freed as long as the reference count is
911 * nonzero.
912 */
913 unsigned int referrers;
914
915 /*
916 * Iff the packed-refs file associated with this instance is
917 * currently locked for writing, this points at the associated
918 * lock (which is owned by somebody else). The referrer count
919 * is also incremented when the file is locked and decremented
920 * when it is unlocked.
921 */
922 struct lock_file *lock;
923
924 /* The metadata from when this packed-refs cache was read */
925 struct stat_validity validity;
926 };
927
928 /*
929 * Future: need to be in "struct repository"
930 * when doing a full libification.
931 */
932 static struct ref_cache {
933 struct ref_cache *next;
934 struct ref_entry *loose;
935 struct packed_ref_cache *packed;
936 /*
937 * The submodule name, or "" for the main repo. We allocate
938 * length 1 rather than FLEX_ARRAY so that the main ref_cache
939 * is initialized correctly.
940 */
941 char name[1];
942 } ref_cache, *submodule_ref_caches;
943
944 /* Lock used for the main packed-refs file: */
945 static struct lock_file packlock;
946
947 /*
948 * Increment the reference count of *packed_refs.
949 */
950 static void acquire_packed_ref_cache(struct packed_ref_cache *packed_refs)
951 {
952 packed_refs->referrers++;
953 }
954
955 /*
956 * Decrease the reference count of *packed_refs. If it goes to zero,
957 * free *packed_refs and return true; otherwise return false.
958 */
959 static int release_packed_ref_cache(struct packed_ref_cache *packed_refs)
960 {
961 if (!--packed_refs->referrers) {
962 free_ref_entry(packed_refs->root);
963 stat_validity_clear(&packed_refs->validity);
964 free(packed_refs);
965 return 1;
966 } else {
967 return 0;
968 }
969 }
970
971 static void clear_packed_ref_cache(struct ref_cache *refs)
972 {
973 if (refs->packed) {
974 struct packed_ref_cache *packed_refs = refs->packed;
975
976 if (packed_refs->lock)
977 die("internal error: packed-ref cache cleared while locked");
978 refs->packed = NULL;
979 release_packed_ref_cache(packed_refs);
980 }
981 }
982
983 static void clear_loose_ref_cache(struct ref_cache *refs)
984 {
985 if (refs->loose) {
986 free_ref_entry(refs->loose);
987 refs->loose = NULL;
988 }
989 }
990
991 static struct ref_cache *create_ref_cache(const char *submodule)
992 {
993 int len;
994 struct ref_cache *refs;
995 if (!submodule)
996 submodule = "";
997 len = strlen(submodule) + 1;
998 refs = xcalloc(1, sizeof(struct ref_cache) + len);
999 memcpy(refs->name, submodule, len);
1000 return refs;
1001 }
1002
1003 /*
1004 * Return a pointer to a ref_cache for the specified submodule. For
1005 * the main repository, use submodule==NULL. The returned structure
1006 * will be allocated and initialized but not necessarily populated; it
1007 * should not be freed.
1008 */
1009 static struct ref_cache *get_ref_cache(const char *submodule)
1010 {
1011 struct ref_cache *refs;
1012
1013 if (!submodule || !*submodule)
1014 return &ref_cache;
1015
1016 for (refs = submodule_ref_caches; refs; refs = refs->next)
1017 if (!strcmp(submodule, refs->name))
1018 return refs;
1019
1020 refs = create_ref_cache(submodule);
1021 refs->next = submodule_ref_caches;
1022 submodule_ref_caches = refs;
1023 return refs;
1024 }
1025
1026 /* The length of a peeled reference line in packed-refs, including EOL: */
1027 #define PEELED_LINE_LENGTH 42
1028
1029 /*
1030 * The packed-refs header line that we write out. Perhaps other
1031 * traits will be added later. The trailing space is required.
1032 */
1033 static const char PACKED_REFS_HEADER[] =
1034 "# pack-refs with: peeled fully-peeled \n";
1035
1036 /*
1037 * Parse one line from a packed-refs file. Write the SHA1 to sha1.
1038 * Return a pointer to the refname within the line (null-terminated),
1039 * or NULL if there was a problem.
1040 */
1041 static const char *parse_ref_line(char *line, unsigned char *sha1)
1042 {
1043 /*
1044 * 42: the answer to everything.
1045 *
1046 * In this case, it happens to be the answer to
1047 * 40 (length of sha1 hex representation)
1048 * +1 (space in between hex and name)
1049 * +1 (newline at the end of the line)
1050 */
1051 int len = strlen(line) - 42;
1052
1053 if (len <= 0)
1054 return NULL;
1055 if (get_sha1_hex(line, sha1) < 0)
1056 return NULL;
1057 if (!isspace(line[40]))
1058 return NULL;
1059 line += 41;
1060 if (isspace(*line))
1061 return NULL;
1062 if (line[len] != '\n')
1063 return NULL;
1064 line[len] = 0;
1065
1066 return line;
1067 }
1068
1069 /*
1070 * Read f, which is a packed-refs file, into dir.
1071 *
1072 * A comment line of the form "# pack-refs with: " may contain zero or
1073 * more traits. We interpret the traits as follows:
1074 *
1075 * No traits:
1076 *
1077 * Probably no references are peeled. But if the file contains a
1078 * peeled value for a reference, we will use it.
1079 *
1080 * peeled:
1081 *
1082 * References under "refs/tags/", if they *can* be peeled, *are*
1083 * peeled in this file. References outside of "refs/tags/" are
1084 * probably not peeled even if they could have been, but if we find
1085 * a peeled value for such a reference we will use it.
1086 *
1087 * fully-peeled:
1088 *
1089 * All references in the file that can be peeled are peeled.
1090 * Inversely (and this is more important), any references in the
1091 * file for which no peeled value is recorded is not peelable. This
1092 * trait should typically be written alongside "peeled" for
1093 * compatibility with older clients, but we do not require it
1094 * (i.e., "peeled" is a no-op if "fully-peeled" is set).
1095 */
1096 static void read_packed_refs(FILE *f, struct ref_dir *dir)
1097 {
1098 struct ref_entry *last = NULL;
1099 char refline[PATH_MAX];
1100 enum { PEELED_NONE, PEELED_TAGS, PEELED_FULLY } peeled = PEELED_NONE;
1101
1102 while (fgets(refline, sizeof(refline), f)) {
1103 unsigned char sha1[20];
1104 const char *refname;
1105 static const char header[] = "# pack-refs with:";
1106
1107 if (!strncmp(refline, header, sizeof(header)-1)) {
1108 const char *traits = refline + sizeof(header) - 1;
1109 if (strstr(traits, " fully-peeled "))
1110 peeled = PEELED_FULLY;
1111 else if (strstr(traits, " peeled "))
1112 peeled = PEELED_TAGS;
1113 /* perhaps other traits later as well */
1114 continue;
1115 }
1116
1117 refname = parse_ref_line(refline, sha1);
1118 if (refname) {
1119 last = create_ref_entry(refname, sha1, REF_ISPACKED, 1);
1120 if (peeled == PEELED_FULLY ||
1121 (peeled == PEELED_TAGS && starts_with(refname, "refs/tags/")))
1122 last->flag |= REF_KNOWS_PEELED;
1123 add_ref(dir, last);
1124 continue;
1125 }
1126 if (last &&
1127 refline[0] == '^' &&
1128 strlen(refline) == PEELED_LINE_LENGTH &&
1129 refline[PEELED_LINE_LENGTH - 1] == '\n' &&
1130 !get_sha1_hex(refline + 1, sha1)) {
1131 hashcpy(last->u.value.peeled, sha1);
1132 /*
1133 * Regardless of what the file header said,
1134 * we definitely know the value of *this*
1135 * reference:
1136 */
1137 last->flag |= REF_KNOWS_PEELED;
1138 }
1139 }
1140 }
1141
1142 /*
1143 * Get the packed_ref_cache for the specified ref_cache, creating it
1144 * if necessary.
1145 */
1146 static struct packed_ref_cache *get_packed_ref_cache(struct ref_cache *refs)
1147 {
1148 const char *packed_refs_file;
1149
1150 if (*refs->name)
1151 packed_refs_file = git_path_submodule(refs->name, "packed-refs");
1152 else
1153 packed_refs_file = git_path("packed-refs");
1154
1155 if (refs->packed &&
1156 !stat_validity_check(&refs->packed->validity, packed_refs_file))
1157 clear_packed_ref_cache(refs);
1158
1159 if (!refs->packed) {
1160 FILE *f;
1161
1162 refs->packed = xcalloc(1, sizeof(*refs->packed));
1163 acquire_packed_ref_cache(refs->packed);
1164 refs->packed->root = create_dir_entry(refs, "", 0, 0);
1165 f = fopen(packed_refs_file, "r");
1166 if (f) {
1167 stat_validity_update(&refs->packed->validity, fileno(f));
1168 read_packed_refs(f, get_ref_dir(refs->packed->root));
1169 fclose(f);
1170 }
1171 }
1172 return refs->packed;
1173 }
1174
1175 static struct ref_dir *get_packed_ref_dir(struct packed_ref_cache *packed_ref_cache)
1176 {
1177 return get_ref_dir(packed_ref_cache->root);
1178 }
1179
1180 static struct ref_dir *get_packed_refs(struct ref_cache *refs)
1181 {
1182 return get_packed_ref_dir(get_packed_ref_cache(refs));
1183 }
1184
1185 void add_packed_ref(const char *refname, const unsigned char *sha1)
1186 {
1187 struct packed_ref_cache *packed_ref_cache =
1188 get_packed_ref_cache(&ref_cache);
1189
1190 if (!packed_ref_cache->lock)
1191 die("internal error: packed refs not locked");
1192 add_ref(get_packed_ref_dir(packed_ref_cache),
1193 create_ref_entry(refname, sha1, REF_ISPACKED, 1));
1194 }
1195
1196 /*
1197 * Read the loose references from the namespace dirname into dir
1198 * (without recursing). dirname must end with '/'. dir must be the
1199 * directory entry corresponding to dirname.
1200 */
1201 static void read_loose_refs(const char *dirname, struct ref_dir *dir)
1202 {
1203 struct ref_cache *refs = dir->ref_cache;
1204 DIR *d;
1205 const char *path;
1206 struct dirent *de;
1207 int dirnamelen = strlen(dirname);
1208 struct strbuf refname;
1209
1210 if (*refs->name)
1211 path = git_path_submodule(refs->name, "%s", dirname);
1212 else
1213 path = git_path("%s", dirname);
1214
1215 d = opendir(path);
1216 if (!d)
1217 return;
1218
1219 strbuf_init(&refname, dirnamelen + 257);
1220 strbuf_add(&refname, dirname, dirnamelen);
1221
1222 while ((de = readdir(d)) != NULL) {
1223 unsigned char sha1[20];
1224 struct stat st;
1225 int flag;
1226 const char *refdir;
1227
1228 if (de->d_name[0] == '.')
1229 continue;
1230 if (ends_with(de->d_name, ".lock"))
1231 continue;
1232 strbuf_addstr(&refname, de->d_name);
1233 refdir = *refs->name
1234 ? git_path_submodule(refs->name, "%s", refname.buf)
1235 : git_path("%s", refname.buf);
1236 if (stat(refdir, &st) < 0) {
1237 ; /* silently ignore */
1238 } else if (S_ISDIR(st.st_mode)) {
1239 strbuf_addch(&refname, '/');
1240 add_entry_to_dir(dir,
1241 create_dir_entry(refs, refname.buf,
1242 refname.len, 1));
1243 } else {
1244 if (*refs->name) {
1245 hashclr(sha1);
1246 flag = 0;
1247 if (resolve_gitlink_ref(refs->name, refname.buf, sha1) < 0) {
1248 hashclr(sha1);
1249 flag |= REF_ISBROKEN;
1250 }
1251 } else if (read_ref_full(refname.buf, sha1, 1, &flag)) {
1252 hashclr(sha1);
1253 flag |= REF_ISBROKEN;
1254 }
1255 add_entry_to_dir(dir,
1256 create_ref_entry(refname.buf, sha1, flag, 1));
1257 }
1258 strbuf_setlen(&refname, dirnamelen);
1259 }
1260 strbuf_release(&refname);
1261 closedir(d);
1262 }
1263
1264 static struct ref_dir *get_loose_refs(struct ref_cache *refs)
1265 {
1266 if (!refs->loose) {
1267 /*
1268 * Mark the top-level directory complete because we
1269 * are about to read the only subdirectory that can
1270 * hold references:
1271 */
1272 refs->loose = create_dir_entry(refs, "", 0, 0);
1273 /*
1274 * Create an incomplete entry for "refs/":
1275 */
1276 add_entry_to_dir(get_ref_dir(refs->loose),
1277 create_dir_entry(refs, "refs/", 5, 1));
1278 }
1279 return get_ref_dir(refs->loose);
1280 }
1281
1282 /* We allow "recursive" symbolic refs. Only within reason, though */
1283 #define MAXDEPTH 5
1284 #define MAXREFLEN (1024)
1285
1286 /*
1287 * Called by resolve_gitlink_ref_recursive() after it failed to read
1288 * from the loose refs in ref_cache refs. Find <refname> in the
1289 * packed-refs file for the submodule.
1290 */
1291 static int resolve_gitlink_packed_ref(struct ref_cache *refs,
1292 const char *refname, unsigned char *sha1)
1293 {
1294 struct ref_entry *ref;
1295 struct ref_dir *dir = get_packed_refs(refs);
1296
1297 ref = find_ref(dir, refname);
1298 if (ref == NULL)
1299 return -1;
1300
1301 hashcpy(sha1, ref->u.value.sha1);
1302 return 0;
1303 }
1304
1305 static int resolve_gitlink_ref_recursive(struct ref_cache *refs,
1306 const char *refname, unsigned char *sha1,
1307 int recursion)
1308 {
1309 int fd, len;
1310 char buffer[128], *p;
1311 char *path;
1312
1313 if (recursion > MAXDEPTH || strlen(refname) > MAXREFLEN)
1314 return -1;
1315 path = *refs->name
1316 ? git_path_submodule(refs->name, "%s", refname)
1317 : git_path("%s", refname);
1318 fd = open(path, O_RDONLY);
1319 if (fd < 0)
1320 return resolve_gitlink_packed_ref(refs, refname, sha1);
1321
1322 len = read(fd, buffer, sizeof(buffer)-1);
1323 close(fd);
1324 if (len < 0)
1325 return -1;
1326 while (len && isspace(buffer[len-1]))
1327 len--;
1328 buffer[len] = 0;
1329
1330 /* Was it a detached head or an old-fashioned symlink? */
1331 if (!get_sha1_hex(buffer, sha1))
1332 return 0;
1333
1334 /* Symref? */
1335 if (strncmp(buffer, "ref:", 4))
1336 return -1;
1337 p = buffer + 4;
1338 while (isspace(*p))
1339 p++;
1340
1341 return resolve_gitlink_ref_recursive(refs, p, sha1, recursion+1);
1342 }
1343
1344 int resolve_gitlink_ref(const char *path, const char *refname, unsigned char *sha1)
1345 {
1346 int len = strlen(path), retval;
1347 char *submodule;
1348 struct ref_cache *refs;
1349
1350 while (len && path[len-1] == '/')
1351 len--;
1352 if (!len)
1353 return -1;
1354 submodule = xstrndup(path, len);
1355 refs = get_ref_cache(submodule);
1356 free(submodule);
1357
1358 retval = resolve_gitlink_ref_recursive(refs, refname, sha1, 0);
1359 return retval;
1360 }
1361
1362 /*
1363 * Return the ref_entry for the given refname from the packed
1364 * references. If it does not exist, return NULL.
1365 */
1366 static struct ref_entry *get_packed_ref(const char *refname)
1367 {
1368 return find_ref(get_packed_refs(&ref_cache), refname);
1369 }
1370
1371 /*
1372 * A loose ref file doesn't exist; check for a packed ref. The
1373 * options are forwarded from resolve_safe_unsafe().
1374 */
1375 static const char *handle_missing_loose_ref(const char *refname,
1376 unsigned char *sha1,
1377 int reading,
1378 int *flag)
1379 {
1380 struct ref_entry *entry;
1381
1382 /*
1383 * The loose reference file does not exist; check for a packed
1384 * reference.
1385 */
1386 entry = get_packed_ref(refname);
1387 if (entry) {
1388 hashcpy(sha1, entry->u.value.sha1);
1389 if (flag)
1390 *flag |= REF_ISPACKED;
1391 return refname;
1392 }
1393 /* The reference is not a packed reference, either. */
1394 if (reading) {
1395 return NULL;
1396 } else {
1397 hashclr(sha1);
1398 return refname;
1399 }
1400 }
1401
1402 /* This function needs to return a meaningful errno on failure */
1403 const char *resolve_ref_unsafe(const char *refname, unsigned char *sha1, int reading, int *flag)
1404 {
1405 int depth = MAXDEPTH;
1406 ssize_t len;
1407 char buffer[256];
1408 static char refname_buffer[256];
1409
1410 if (flag)
1411 *flag = 0;
1412
1413 if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
1414 errno = EINVAL;
1415 return NULL;
1416 }
1417
1418 for (;;) {
1419 char path[PATH_MAX];
1420 struct stat st;
1421 char *buf;
1422 int fd;
1423
1424 if (--depth < 0) {
1425 errno = ELOOP;
1426 return NULL;
1427 }
1428
1429 git_snpath(path, sizeof(path), "%s", refname);
1430
1431 /*
1432 * We might have to loop back here to avoid a race
1433 * condition: first we lstat() the file, then we try
1434 * to read it as a link or as a file. But if somebody
1435 * changes the type of the file (file <-> directory
1436 * <-> symlink) between the lstat() and reading, then
1437 * we don't want to report that as an error but rather
1438 * try again starting with the lstat().
1439 */
1440 stat_ref:
1441 if (lstat(path, &st) < 0) {
1442 if (errno == ENOENT)
1443 return handle_missing_loose_ref(refname, sha1,
1444 reading, flag);
1445 else
1446 return NULL;
1447 }
1448
1449 /* Follow "normalized" - ie "refs/.." symlinks by hand */
1450 if (S_ISLNK(st.st_mode)) {
1451 len = readlink(path, buffer, sizeof(buffer)-1);
1452 if (len < 0) {
1453 if (errno == ENOENT || errno == EINVAL)
1454 /* inconsistent with lstat; retry */
1455 goto stat_ref;
1456 else
1457 return NULL;
1458 }
1459 buffer[len] = 0;
1460 if (starts_with(buffer, "refs/") &&
1461 !check_refname_format(buffer, 0)) {
1462 strcpy(refname_buffer, buffer);
1463 refname = refname_buffer;
1464 if (flag)
1465 *flag |= REF_ISSYMREF;
1466 continue;
1467 }
1468 }
1469
1470 /* Is it a directory? */
1471 if (S_ISDIR(st.st_mode)) {
1472 errno = EISDIR;
1473 return NULL;
1474 }
1475
1476 /*
1477 * Anything else, just open it and try to use it as
1478 * a ref
1479 */
1480 fd = open(path, O_RDONLY);
1481 if (fd < 0) {
1482 if (errno == ENOENT)
1483 /* inconsistent with lstat; retry */
1484 goto stat_ref;
1485 else
1486 return NULL;
1487 }
1488 len = read_in_full(fd, buffer, sizeof(buffer)-1);
1489 if (len < 0) {
1490 int save_errno = errno;
1491 close(fd);
1492 errno = save_errno;
1493 return NULL;
1494 }
1495 close(fd);
1496 while (len && isspace(buffer[len-1]))
1497 len--;
1498 buffer[len] = '\0';
1499
1500 /*
1501 * Is it a symbolic ref?
1502 */
1503 if (!starts_with(buffer, "ref:")) {
1504 /*
1505 * Please note that FETCH_HEAD has a second
1506 * line containing other data.
1507 */
1508 if (get_sha1_hex(buffer, sha1) ||
1509 (buffer[40] != '\0' && !isspace(buffer[40]))) {
1510 if (flag)
1511 *flag |= REF_ISBROKEN;
1512 errno = EINVAL;
1513 return NULL;
1514 }
1515 return refname;
1516 }
1517 if (flag)
1518 *flag |= REF_ISSYMREF;
1519 buf = buffer + 4;
1520 while (isspace(*buf))
1521 buf++;
1522 if (check_refname_format(buf, REFNAME_ALLOW_ONELEVEL)) {
1523 if (flag)
1524 *flag |= REF_ISBROKEN;
1525 errno = EINVAL;
1526 return NULL;
1527 }
1528 refname = strcpy(refname_buffer, buf);
1529 }
1530 }
1531
1532 char *resolve_refdup(const char *ref, unsigned char *sha1, int reading, int *flag)
1533 {
1534 const char *ret = resolve_ref_unsafe(ref, sha1, reading, flag);
1535 return ret ? xstrdup(ret) : NULL;
1536 }
1537
1538 /* The argument to filter_refs */
1539 struct ref_filter {
1540 const char *pattern;
1541 each_ref_fn *fn;
1542 void *cb_data;
1543 };
1544
1545 int read_ref_full(const char *refname, unsigned char *sha1, int reading, int *flags)
1546 {
1547 if (resolve_ref_unsafe(refname, sha1, reading, flags))
1548 return 0;
1549 return -1;
1550 }
1551
1552 int read_ref(const char *refname, unsigned char *sha1)
1553 {
1554 return read_ref_full(refname, sha1, 1, NULL);
1555 }
1556
1557 int ref_exists(const char *refname)
1558 {
1559 unsigned char sha1[20];
1560 return !!resolve_ref_unsafe(refname, sha1, 1, NULL);
1561 }
1562
1563 static int filter_refs(const char *refname, const unsigned char *sha1, int flags,
1564 void *data)
1565 {
1566 struct ref_filter *filter = (struct ref_filter *)data;
1567 if (wildmatch(filter->pattern, refname, 0, NULL))
1568 return 0;
1569 return filter->fn(refname, sha1, flags, filter->cb_data);
1570 }
1571
1572 enum peel_status {
1573 /* object was peeled successfully: */
1574 PEEL_PEELED = 0,
1575
1576 /*
1577 * object cannot be peeled because the named object (or an
1578 * object referred to by a tag in the peel chain), does not
1579 * exist.
1580 */
1581 PEEL_INVALID = -1,
1582
1583 /* object cannot be peeled because it is not a tag: */
1584 PEEL_NON_TAG = -2,
1585
1586 /* ref_entry contains no peeled value because it is a symref: */
1587 PEEL_IS_SYMREF = -3,
1588
1589 /*
1590 * ref_entry cannot be peeled because it is broken (i.e., the
1591 * symbolic reference cannot even be resolved to an object
1592 * name):
1593 */
1594 PEEL_BROKEN = -4
1595 };
1596
1597 /*
1598 * Peel the named object; i.e., if the object is a tag, resolve the
1599 * tag recursively until a non-tag is found. If successful, store the
1600 * result to sha1 and return PEEL_PEELED. If the object is not a tag
1601 * or is not valid, return PEEL_NON_TAG or PEEL_INVALID, respectively,
1602 * and leave sha1 unchanged.
1603 */
1604 static enum peel_status peel_object(const unsigned char *name, unsigned char *sha1)
1605 {
1606 struct object *o = lookup_unknown_object(name);
1607
1608 if (o->type == OBJ_NONE) {
1609 int type = sha1_object_info(name, NULL);
1610 if (type < 0 || !object_as_type(o, type, 0))
1611 return PEEL_INVALID;
1612 }
1613
1614 if (o->type != OBJ_TAG)
1615 return PEEL_NON_TAG;
1616
1617 o = deref_tag_noverify(o);
1618 if (!o)
1619 return PEEL_INVALID;
1620
1621 hashcpy(sha1, o->sha1);
1622 return PEEL_PEELED;
1623 }
1624
1625 /*
1626 * Peel the entry (if possible) and return its new peel_status. If
1627 * repeel is true, re-peel the entry even if there is an old peeled
1628 * value that is already stored in it.
1629 *
1630 * It is OK to call this function with a packed reference entry that
1631 * might be stale and might even refer to an object that has since
1632 * been garbage-collected. In such a case, if the entry has
1633 * REF_KNOWS_PEELED then leave the status unchanged and return
1634 * PEEL_PEELED or PEEL_NON_TAG; otherwise, return PEEL_INVALID.
1635 */
1636 static enum peel_status peel_entry(struct ref_entry *entry, int repeel)
1637 {
1638 enum peel_status status;
1639
1640 if (entry->flag & REF_KNOWS_PEELED) {
1641 if (repeel) {
1642 entry->flag &= ~REF_KNOWS_PEELED;
1643 hashclr(entry->u.value.peeled);
1644 } else {
1645 return is_null_sha1(entry->u.value.peeled) ?
1646 PEEL_NON_TAG : PEEL_PEELED;
1647 }
1648 }
1649 if (entry->flag & REF_ISBROKEN)
1650 return PEEL_BROKEN;
1651 if (entry->flag & REF_ISSYMREF)
1652 return PEEL_IS_SYMREF;
1653
1654 status = peel_object(entry->u.value.sha1, entry->u.value.peeled);
1655 if (status == PEEL_PEELED || status == PEEL_NON_TAG)
1656 entry->flag |= REF_KNOWS_PEELED;
1657 return status;
1658 }
1659
1660 int peel_ref(const char *refname, unsigned char *sha1)
1661 {
1662 int flag;
1663 unsigned char base[20];
1664
1665 if (current_ref && (current_ref->name == refname
1666 || !strcmp(current_ref->name, refname))) {
1667 if (peel_entry(current_ref, 0))
1668 return -1;
1669 hashcpy(sha1, current_ref->u.value.peeled);
1670 return 0;
1671 }
1672
1673 if (read_ref_full(refname, base, 1, &flag))
1674 return -1;
1675
1676 /*
1677 * If the reference is packed, read its ref_entry from the
1678 * cache in the hope that we already know its peeled value.
1679 * We only try this optimization on packed references because
1680 * (a) forcing the filling of the loose reference cache could
1681 * be expensive and (b) loose references anyway usually do not
1682 * have REF_KNOWS_PEELED.
1683 */
1684 if (flag & REF_ISPACKED) {
1685 struct ref_entry *r = get_packed_ref(refname);
1686 if (r) {
1687 if (peel_entry(r, 0))
1688 return -1;
1689 hashcpy(sha1, r->u.value.peeled);
1690 return 0;
1691 }
1692 }
1693
1694 return peel_object(base, sha1);
1695 }
1696
1697 struct warn_if_dangling_data {
1698 FILE *fp;
1699 const char *refname;
1700 const struct string_list *refnames;
1701 const char *msg_fmt;
1702 };
1703
1704 static int warn_if_dangling_symref(const char *refname, const unsigned char *sha1,
1705 int flags, void *cb_data)
1706 {
1707 struct warn_if_dangling_data *d = cb_data;
1708 const char *resolves_to;
1709 unsigned char junk[20];
1710
1711 if (!(flags & REF_ISSYMREF))
1712 return 0;
1713
1714 resolves_to = resolve_ref_unsafe(refname, junk, 0, NULL);
1715 if (!resolves_to
1716 || (d->refname
1717 ? strcmp(resolves_to, d->refname)
1718 : !string_list_has_string(d->refnames, resolves_to))) {
1719 return 0;
1720 }
1721
1722 fprintf(d->fp, d->msg_fmt, refname);
1723 fputc('\n', d->fp);
1724 return 0;
1725 }
1726
1727 void warn_dangling_symref(FILE *fp, const char *msg_fmt, const char *refname)
1728 {
1729 struct warn_if_dangling_data data;
1730
1731 data.fp = fp;
1732 data.refname = refname;
1733 data.refnames = NULL;
1734 data.msg_fmt = msg_fmt;
1735 for_each_rawref(warn_if_dangling_symref, &data);
1736 }
1737
1738 void warn_dangling_symrefs(FILE *fp, const char *msg_fmt, const struct string_list *refnames)
1739 {
1740 struct warn_if_dangling_data data;
1741
1742 data.fp = fp;
1743 data.refname = NULL;
1744 data.refnames = refnames;
1745 data.msg_fmt = msg_fmt;
1746 for_each_rawref(warn_if_dangling_symref, &data);
1747 }
1748
1749 /*
1750 * Call fn for each reference in the specified ref_cache, omitting
1751 * references not in the containing_dir of base. fn is called for all
1752 * references, including broken ones. If fn ever returns a non-zero
1753 * value, stop the iteration and return that value; otherwise, return
1754 * 0.
1755 */
1756 static int do_for_each_entry(struct ref_cache *refs, const char *base,
1757 each_ref_entry_fn fn, void *cb_data)
1758 {
1759 struct packed_ref_cache *packed_ref_cache;
1760 struct ref_dir *loose_dir;
1761 struct ref_dir *packed_dir;
1762 int retval = 0;
1763
1764 /*
1765 * We must make sure that all loose refs are read before accessing the
1766 * packed-refs file; this avoids a race condition in which loose refs
1767 * are migrated to the packed-refs file by a simultaneous process, but
1768 * our in-memory view is from before the migration. get_packed_ref_cache()
1769 * takes care of making sure our view is up to date with what is on
1770 * disk.
1771 */
1772 loose_dir = get_loose_refs(refs);
1773 if (base && *base) {
1774 loose_dir = find_containing_dir(loose_dir, base, 0);
1775 }
1776 if (loose_dir)
1777 prime_ref_dir(loose_dir);
1778
1779 packed_ref_cache = get_packed_ref_cache(refs);
1780 acquire_packed_ref_cache(packed_ref_cache);
1781 packed_dir = get_packed_ref_dir(packed_ref_cache);
1782 if (base && *base) {
1783 packed_dir = find_containing_dir(packed_dir, base, 0);
1784 }
1785
1786 if (packed_dir && loose_dir) {
1787 sort_ref_dir(packed_dir);
1788 sort_ref_dir(loose_dir);
1789 retval = do_for_each_entry_in_dirs(
1790 packed_dir, loose_dir, fn, cb_data);
1791 } else if (packed_dir) {
1792 sort_ref_dir(packed_dir);
1793 retval = do_for_each_entry_in_dir(
1794 packed_dir, 0, fn, cb_data);
1795 } else if (loose_dir) {
1796 sort_ref_dir(loose_dir);
1797 retval = do_for_each_entry_in_dir(
1798 loose_dir, 0, fn, cb_data);
1799 }
1800
1801 release_packed_ref_cache(packed_ref_cache);
1802 return retval;
1803 }
1804
1805 /*
1806 * Call fn for each reference in the specified ref_cache for which the
1807 * refname begins with base. If trim is non-zero, then trim that many
1808 * characters off the beginning of each refname before passing the
1809 * refname to fn. flags can be DO_FOR_EACH_INCLUDE_BROKEN to include
1810 * broken references in the iteration. If fn ever returns a non-zero
1811 * value, stop the iteration and return that value; otherwise, return
1812 * 0.
1813 */
1814 static int do_for_each_ref(struct ref_cache *refs, const char *base,
1815 each_ref_fn fn, int trim, int flags, void *cb_data)
1816 {
1817 struct ref_entry_cb data;
1818 data.base = base;
1819 data.trim = trim;
1820 data.flags = flags;
1821 data.fn = fn;
1822 data.cb_data = cb_data;
1823
1824 return do_for_each_entry(refs, base, do_one_ref, &data);
1825 }
1826
1827 static int do_head_ref(const char *submodule, each_ref_fn fn, void *cb_data)
1828 {
1829 unsigned char sha1[20];
1830 int flag;
1831
1832 if (submodule) {
1833 if (resolve_gitlink_ref(submodule, "HEAD", sha1) == 0)
1834 return fn("HEAD", sha1, 0, cb_data);
1835
1836 return 0;
1837 }
1838
1839 if (!read_ref_full("HEAD", sha1, 1, &flag))
1840 return fn("HEAD", sha1, flag, cb_data);
1841
1842 return 0;
1843 }
1844
1845 int head_ref(each_ref_fn fn, void *cb_data)
1846 {
1847 return do_head_ref(NULL, fn, cb_data);
1848 }
1849
1850 int head_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
1851 {
1852 return do_head_ref(submodule, fn, cb_data);
1853 }
1854
1855 int for_each_ref(each_ref_fn fn, void *cb_data)
1856 {
1857 return do_for_each_ref(&ref_cache, "", fn, 0, 0, cb_data);
1858 }
1859
1860 int for_each_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
1861 {
1862 return do_for_each_ref(get_ref_cache(submodule), "", fn, 0, 0, cb_data);
1863 }
1864
1865 int for_each_ref_in(const char *prefix, each_ref_fn fn, void *cb_data)
1866 {
1867 return do_for_each_ref(&ref_cache, prefix, fn, strlen(prefix), 0, cb_data);
1868 }
1869
1870 int for_each_ref_in_submodule(const char *submodule, const char *prefix,
1871 each_ref_fn fn, void *cb_data)
1872 {
1873 return do_for_each_ref(get_ref_cache(submodule), prefix, fn, strlen(prefix), 0, cb_data);
1874 }
1875
1876 int for_each_tag_ref(each_ref_fn fn, void *cb_data)
1877 {
1878 return for_each_ref_in("refs/tags/", fn, cb_data);
1879 }
1880
1881 int for_each_tag_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
1882 {
1883 return for_each_ref_in_submodule(submodule, "refs/tags/", fn, cb_data);
1884 }
1885
1886 int for_each_branch_ref(each_ref_fn fn, void *cb_data)
1887 {
1888 return for_each_ref_in("refs/heads/", fn, cb_data);
1889 }
1890
1891 int for_each_branch_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
1892 {
1893 return for_each_ref_in_submodule(submodule, "refs/heads/", fn, cb_data);
1894 }
1895
1896 int for_each_remote_ref(each_ref_fn fn, void *cb_data)
1897 {
1898 return for_each_ref_in("refs/remotes/", fn, cb_data);
1899 }
1900
1901 int for_each_remote_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
1902 {
1903 return for_each_ref_in_submodule(submodule, "refs/remotes/", fn, cb_data);
1904 }
1905
1906 int for_each_replace_ref(each_ref_fn fn, void *cb_data)
1907 {
1908 return do_for_each_ref(&ref_cache, "refs/replace/", fn, 13, 0, cb_data);
1909 }
1910
1911 int head_ref_namespaced(each_ref_fn fn, void *cb_data)
1912 {
1913 struct strbuf buf = STRBUF_INIT;
1914 int ret = 0;
1915 unsigned char sha1[20];
1916 int flag;
1917
1918 strbuf_addf(&buf, "%sHEAD", get_git_namespace());
1919 if (!read_ref_full(buf.buf, sha1, 1, &flag))
1920 ret = fn(buf.buf, sha1, flag, cb_data);
1921 strbuf_release(&buf);
1922
1923 return ret;
1924 }
1925
1926 int for_each_namespaced_ref(each_ref_fn fn, void *cb_data)
1927 {
1928 struct strbuf buf = STRBUF_INIT;
1929 int ret;
1930 strbuf_addf(&buf, "%srefs/", get_git_namespace());
1931 ret = do_for_each_ref(&ref_cache, buf.buf, fn, 0, 0, cb_data);
1932 strbuf_release(&buf);
1933 return ret;
1934 }
1935
1936 int for_each_glob_ref_in(each_ref_fn fn, const char *pattern,
1937 const char *prefix, void *cb_data)
1938 {
1939 struct strbuf real_pattern = STRBUF_INIT;
1940 struct ref_filter filter;
1941 int ret;
1942
1943 if (!prefix && !starts_with(pattern, "refs/"))
1944 strbuf_addstr(&real_pattern, "refs/");
1945 else if (prefix)
1946 strbuf_addstr(&real_pattern, prefix);
1947 strbuf_addstr(&real_pattern, pattern);
1948
1949 if (!has_glob_specials(pattern)) {
1950 /* Append implied '/' '*' if not present. */
1951 if (real_pattern.buf[real_pattern.len - 1] != '/')
1952 strbuf_addch(&real_pattern, '/');
1953 /* No need to check for '*', there is none. */
1954 strbuf_addch(&real_pattern, '*');
1955 }
1956
1957 filter.pattern = real_pattern.buf;
1958 filter.fn = fn;
1959 filter.cb_data = cb_data;
1960 ret = for_each_ref(filter_refs, &filter);
1961
1962 strbuf_release(&real_pattern);
1963 return ret;
1964 }
1965
1966 int for_each_glob_ref(each_ref_fn fn, const char *pattern, void *cb_data)
1967 {
1968 return for_each_glob_ref_in(fn, pattern, NULL, cb_data);
1969 }
1970
1971 int for_each_rawref(each_ref_fn fn, void *cb_data)
1972 {
1973 return do_for_each_ref(&ref_cache, "", fn, 0,
1974 DO_FOR_EACH_INCLUDE_BROKEN, cb_data);
1975 }
1976
1977 const char *prettify_refname(const char *name)
1978 {
1979 return name + (
1980 starts_with(name, "refs/heads/") ? 11 :
1981 starts_with(name, "refs/tags/") ? 10 :
1982 starts_with(name, "refs/remotes/") ? 13 :
1983 0);
1984 }
1985
1986 static const char *ref_rev_parse_rules[] = {
1987 "%.*s",
1988 "refs/%.*s",
1989 "refs/tags/%.*s",
1990 "refs/heads/%.*s",
1991 "refs/remotes/%.*s",
1992 "refs/remotes/%.*s/HEAD",
1993 NULL
1994 };
1995
1996 int refname_match(const char *abbrev_name, const char *full_name)
1997 {
1998 const char **p;
1999 const int abbrev_name_len = strlen(abbrev_name);
2000
2001 for (p = ref_rev_parse_rules; *p; p++) {
2002 if (!strcmp(full_name, mkpath(*p, abbrev_name_len, abbrev_name))) {
2003 return 1;
2004 }
2005 }
2006
2007 return 0;
2008 }
2009
2010 /* This function should make sure errno is meaningful on error */
2011 static struct ref_lock *verify_lock(struct ref_lock *lock,
2012 const unsigned char *old_sha1, int mustexist)
2013 {
2014 if (read_ref_full(lock->ref_name, lock->old_sha1, mustexist, NULL)) {
2015 int save_errno = errno;
2016 error("Can't verify ref %s", lock->ref_name);
2017 unlock_ref(lock);
2018 errno = save_errno;
2019 return NULL;
2020 }
2021 if (hashcmp(lock->old_sha1, old_sha1)) {
2022 error("Ref %s is at %s but expected %s", lock->ref_name,
2023 sha1_to_hex(lock->old_sha1), sha1_to_hex(old_sha1));
2024 unlock_ref(lock);
2025 errno = EBUSY;
2026 return NULL;
2027 }
2028 return lock;
2029 }
2030
2031 static int remove_empty_directories(const char *file)
2032 {
2033 /* we want to create a file but there is a directory there;
2034 * if that is an empty directory (or a directory that contains
2035 * only empty directories), remove them.
2036 */
2037 struct strbuf path;
2038 int result, save_errno;
2039
2040 strbuf_init(&path, 20);
2041 strbuf_addstr(&path, file);
2042
2043 result = remove_dir_recursively(&path, REMOVE_DIR_EMPTY_ONLY);
2044 save_errno = errno;
2045
2046 strbuf_release(&path);
2047 errno = save_errno;
2048
2049 return result;
2050 }
2051
2052 /*
2053 * *string and *len will only be substituted, and *string returned (for
2054 * later free()ing) if the string passed in is a magic short-hand form
2055 * to name a branch.
2056 */
2057 static char *substitute_branch_name(const char **string, int *len)
2058 {
2059 struct strbuf buf = STRBUF_INIT;
2060 int ret = interpret_branch_name(*string, *len, &buf);
2061
2062 if (ret == *len) {
2063 size_t size;
2064 *string = strbuf_detach(&buf, &size);
2065 *len = size;
2066 return (char *)*string;
2067 }
2068
2069 return NULL;
2070 }
2071
2072 int dwim_ref(const char *str, int len, unsigned char *sha1, char **ref)
2073 {
2074 char *last_branch = substitute_branch_name(&str, &len);
2075 const char **p, *r;
2076 int refs_found = 0;
2077
2078 *ref = NULL;
2079 for (p = ref_rev_parse_rules; *p; p++) {
2080 char fullref[PATH_MAX];
2081 unsigned char sha1_from_ref[20];
2082 unsigned char *this_result;
2083 int flag;
2084
2085 this_result = refs_found ? sha1_from_ref : sha1;
2086 mksnpath(fullref, sizeof(fullref), *p, len, str);
2087 r = resolve_ref_unsafe(fullref, this_result, 1, &flag);
2088 if (r) {
2089 if (!refs_found++)
2090 *ref = xstrdup(r);
2091 if (!warn_ambiguous_refs)
2092 break;
2093 } else if ((flag & REF_ISSYMREF) && strcmp(fullref, "HEAD")) {
2094 warning("ignoring dangling symref %s.", fullref);
2095 } else if ((flag & REF_ISBROKEN) && strchr(fullref, '/')) {
2096 warning("ignoring broken ref %s.", fullref);
2097 }
2098 }
2099 free(last_branch);
2100 return refs_found;
2101 }
2102
2103 int dwim_log(const char *str, int len, unsigned char *sha1, char **log)
2104 {
2105 char *last_branch = substitute_branch_name(&str, &len);
2106 const char **p;
2107 int logs_found = 0;
2108
2109 *log = NULL;
2110 for (p = ref_rev_parse_rules; *p; p++) {
2111 unsigned char hash[20];
2112 char path[PATH_MAX];
2113 const char *ref, *it;
2114
2115 mksnpath(path, sizeof(path), *p, len, str);
2116 ref = resolve_ref_unsafe(path, hash, 1, NULL);
2117 if (!ref)
2118 continue;
2119 if (reflog_exists(path))
2120 it = path;
2121 else if (strcmp(ref, path) && reflog_exists(ref))
2122 it = ref;
2123 else
2124 continue;
2125 if (!logs_found++) {
2126 *log = xstrdup(it);
2127 hashcpy(sha1, hash);
2128 }
2129 if (!warn_ambiguous_refs)
2130 break;
2131 }
2132 free(last_branch);
2133 return logs_found;
2134 }
2135
2136 /*
2137 * Locks a "refs/" ref returning the lock on success and NULL on failure.
2138 * On failure errno is set to something meaningful.
2139 */
2140 static struct ref_lock *lock_ref_sha1_basic(const char *refname,
2141 const unsigned char *old_sha1,
2142 int flags, int *type_p)
2143 {
2144 char *ref_file;
2145 const char *orig_refname = refname;
2146 struct ref_lock *lock;
2147 int last_errno = 0;
2148 int type, lflags;
2149 int mustexist = (old_sha1 && !is_null_sha1(old_sha1));
2150 int missing = 0;
2151 int attempts_remaining = 3;
2152
2153 lock = xcalloc(1, sizeof(struct ref_lock));
2154 lock->lock_fd = -1;
2155
2156 refname = resolve_ref_unsafe(refname, lock->old_sha1, mustexist, &type);
2157 if (!refname && errno == EISDIR) {
2158 /* we are trying to lock foo but we used to
2159 * have foo/bar which now does not exist;
2160 * it is normal for the empty directory 'foo'
2161 * to remain.
2162 */
2163 ref_file = git_path("%s", orig_refname);
2164 if (remove_empty_directories(ref_file)) {
2165 last_errno = errno;
2166 error("there are still refs under '%s'", orig_refname);
2167 goto error_return;
2168 }
2169 refname = resolve_ref_unsafe(orig_refname, lock->old_sha1, mustexist, &type);
2170 }
2171 if (type_p)
2172 *type_p = type;
2173 if (!refname) {
2174 last_errno = errno;
2175 error("unable to resolve reference %s: %s",
2176 orig_refname, strerror(errno));
2177 goto error_return;
2178 }
2179 missing = is_null_sha1(lock->old_sha1);
2180 /* When the ref did not exist and we are creating it,
2181 * make sure there is no existing ref that is packed
2182 * whose name begins with our refname, nor a ref whose
2183 * name is a proper prefix of our refname.
2184 */
2185 if (missing &&
2186 !is_refname_available(refname, NULL, get_packed_refs(&ref_cache))) {
2187 last_errno = ENOTDIR;
2188 goto error_return;
2189 }
2190
2191 lock->lk = xcalloc(1, sizeof(struct lock_file));
2192
2193 lflags = 0;
2194 if (flags & REF_NODEREF) {
2195 refname = orig_refname;
2196 lflags |= LOCK_NO_DEREF;
2197 }
2198 lock->ref_name = xstrdup(refname);
2199 lock->orig_ref_name = xstrdup(orig_refname);
2200 ref_file = git_path("%s", refname);
2201 if (missing)
2202 lock->force_write = 1;
2203 if ((flags & REF_NODEREF) && (type & REF_ISSYMREF))
2204 lock->force_write = 1;
2205
2206 retry:
2207 switch (safe_create_leading_directories(ref_file)) {
2208 case SCLD_OK:
2209 break; /* success */
2210 case SCLD_VANISHED:
2211 if (--attempts_remaining > 0)
2212 goto retry;
2213 /* fall through */
2214 default:
2215 last_errno = errno;
2216 error("unable to create directory for %s", ref_file);
2217 goto error_return;
2218 }
2219
2220 lock->lock_fd = hold_lock_file_for_update(lock->lk, ref_file, lflags);
2221 if (lock->lock_fd < 0) {
2222 if (errno == ENOENT && --attempts_remaining > 0)
2223 /*
2224 * Maybe somebody just deleted one of the
2225 * directories leading to ref_file. Try
2226 * again:
2227 */
2228 goto retry;
2229 else
2230 unable_to_lock_die(ref_file, errno);
2231 }
2232 return old_sha1 ? verify_lock(lock, old_sha1, mustexist) : lock;
2233
2234 error_return:
2235 unlock_ref(lock);
2236 errno = last_errno;
2237 return NULL;
2238 }
2239
2240 struct ref_lock *lock_any_ref_for_update(const char *refname,
2241 const unsigned char *old_sha1,
2242 int flags, int *type_p)
2243 {
2244 if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL))
2245 return NULL;
2246 return lock_ref_sha1_basic(refname, old_sha1, flags, type_p);
2247 }
2248
2249 /*
2250 * Write an entry to the packed-refs file for the specified refname.
2251 * If peeled is non-NULL, write it as the entry's peeled value.
2252 */
2253 static void write_packed_entry(FILE *fh, char *refname, unsigned char *sha1,
2254 unsigned char *peeled)
2255 {
2256 fprintf_or_die(fh, "%s %s\n", sha1_to_hex(sha1), refname);
2257 if (peeled)
2258 fprintf_or_die(fh, "^%s\n", sha1_to_hex(peeled));
2259 }
2260
2261 /*
2262 * An each_ref_entry_fn that writes the entry to a packed-refs file.
2263 */
2264 static int write_packed_entry_fn(struct ref_entry *entry, void *cb_data)
2265 {
2266 enum peel_status peel_status = peel_entry(entry, 0);
2267
2268 if (peel_status != PEEL_PEELED && peel_status != PEEL_NON_TAG)
2269 error("internal error: %s is not a valid packed reference!",
2270 entry->name);
2271 write_packed_entry(cb_data, entry->name, entry->u.value.sha1,
2272 peel_status == PEEL_PEELED ?
2273 entry->u.value.peeled : NULL);
2274 return 0;
2275 }
2276
2277 /* This should return a meaningful errno on failure */
2278 int lock_packed_refs(int flags)
2279 {
2280 struct packed_ref_cache *packed_ref_cache;
2281
2282 if (hold_lock_file_for_update(&packlock, git_path("packed-refs"), flags) < 0)
2283 return -1;
2284 /*
2285 * Get the current packed-refs while holding the lock. If the
2286 * packed-refs file has been modified since we last read it,
2287 * this will automatically invalidate the cache and re-read
2288 * the packed-refs file.
2289 */
2290 packed_ref_cache = get_packed_ref_cache(&ref_cache);
2291 packed_ref_cache->lock = &packlock;
2292 /* Increment the reference count to prevent it from being freed: */
2293 acquire_packed_ref_cache(packed_ref_cache);
2294 return 0;
2295 }
2296
2297 /*
2298 * Commit the packed refs changes.
2299 * On error we must make sure that errno contains a meaningful value.
2300 */
2301 int commit_packed_refs(void)
2302 {
2303 struct packed_ref_cache *packed_ref_cache =
2304 get_packed_ref_cache(&ref_cache);
2305 int error = 0;
2306 int save_errno = 0;
2307 FILE *out;
2308
2309 if (!packed_ref_cache->lock)
2310 die("internal error: packed-refs not locked");
2311
2312 out = fdopen(packed_ref_cache->lock->fd, "w");
2313 if (!out)
2314 die_errno("unable to fdopen packed-refs descriptor");
2315
2316 fprintf_or_die(out, "%s", PACKED_REFS_HEADER);
2317 do_for_each_entry_in_dir(get_packed_ref_dir(packed_ref_cache),
2318 0, write_packed_entry_fn, out);
2319 if (fclose(out))
2320 die_errno("write error");
2321 packed_ref_cache->lock->fd = -1;
2322
2323 if (commit_lock_file(packed_ref_cache->lock)) {
2324 save_errno = errno;
2325 error = -1;
2326 }
2327 packed_ref_cache->lock = NULL;
2328 release_packed_ref_cache(packed_ref_cache);
2329 errno = save_errno;
2330 return error;
2331 }
2332
2333 void rollback_packed_refs(void)
2334 {
2335 struct packed_ref_cache *packed_ref_cache =
2336 get_packed_ref_cache(&ref_cache);
2337
2338 if (!packed_ref_cache->lock)
2339 die("internal error: packed-refs not locked");
2340 rollback_lock_file(packed_ref_cache->lock);
2341 packed_ref_cache->lock = NULL;
2342 release_packed_ref_cache(packed_ref_cache);
2343 clear_packed_ref_cache(&ref_cache);
2344 }
2345
2346 struct ref_to_prune {
2347 struct ref_to_prune *next;
2348 unsigned char sha1[20];
2349 char name[FLEX_ARRAY];
2350 };
2351
2352 struct pack_refs_cb_data {
2353 unsigned int flags;
2354 struct ref_dir *packed_refs;
2355 struct ref_to_prune *ref_to_prune;
2356 };
2357
2358 /*
2359 * An each_ref_entry_fn that is run over loose references only. If
2360 * the loose reference can be packed, add an entry in the packed ref
2361 * cache. If the reference should be pruned, also add it to
2362 * ref_to_prune in the pack_refs_cb_data.
2363 */
2364 static int pack_if_possible_fn(struct ref_entry *entry, void *cb_data)
2365 {
2366 struct pack_refs_cb_data *cb = cb_data;
2367 enum peel_status peel_status;
2368 struct ref_entry *packed_entry;
2369 int is_tag_ref = starts_with(entry->name, "refs/tags/");
2370
2371 /* ALWAYS pack tags */
2372 if (!(cb->flags & PACK_REFS_ALL) && !is_tag_ref)
2373 return 0;
2374
2375 /* Do not pack symbolic or broken refs: */
2376 if ((entry->flag & REF_ISSYMREF) || !ref_resolves_to_object(entry))
2377 return 0;
2378
2379 /* Add a packed ref cache entry equivalent to the loose entry. */
2380 peel_status = peel_entry(entry, 1);
2381 if (peel_status != PEEL_PEELED && peel_status != PEEL_NON_TAG)
2382 die("internal error peeling reference %s (%s)",
2383 entry->name, sha1_to_hex(entry->u.value.sha1));
2384 packed_entry = find_ref(cb->packed_refs, entry->name);
2385 if (packed_entry) {
2386 /* Overwrite existing packed entry with info from loose entry */
2387 packed_entry->flag = REF_ISPACKED | REF_KNOWS_PEELED;
2388 hashcpy(packed_entry->u.value.sha1, entry->u.value.sha1);
2389 } else {
2390 packed_entry = create_ref_entry(entry->name, entry->u.value.sha1,
2391 REF_ISPACKED | REF_KNOWS_PEELED, 0);
2392 add_ref(cb->packed_refs, packed_entry);
2393 }
2394 hashcpy(packed_entry->u.value.peeled, entry->u.value.peeled);
2395
2396 /* Schedule the loose reference for pruning if requested. */
2397 if ((cb->flags & PACK_REFS_PRUNE)) {
2398 int namelen = strlen(entry->name) + 1;
2399 struct ref_to_prune *n = xcalloc(1, sizeof(*n) + namelen);
2400 hashcpy(n->sha1, entry->u.value.sha1);
2401 strcpy(n->name, entry->name);
2402 n->next = cb->ref_to_prune;
2403 cb->ref_to_prune = n;
2404 }
2405 return 0;
2406 }
2407
2408 /*
2409 * Remove empty parents, but spare refs/ and immediate subdirs.
2410 * Note: munges *name.
2411 */
2412 static void try_remove_empty_parents(char *name)
2413 {
2414 char *p, *q;
2415 int i;
2416 p = name;
2417 for (i = 0; i < 2; i++) { /* refs/{heads,tags,...}/ */
2418 while (*p && *p != '/')
2419 p++;
2420 /* tolerate duplicate slashes; see check_refname_format() */
2421 while (*p == '/')
2422 p++;
2423 }
2424 for (q = p; *q; q++)
2425 ;
2426 while (1) {
2427 while (q > p && *q != '/')
2428 q--;
2429 while (q > p && *(q-1) == '/')
2430 q--;
2431 if (q == p)
2432 break;
2433 *q = '\0';
2434 if (rmdir(git_path("%s", name)))
2435 break;
2436 }
2437 }
2438
2439 /* make sure nobody touched the ref, and unlink */
2440 static void prune_ref(struct ref_to_prune *r)
2441 {
2442 struct ref_transaction *transaction;
2443 struct strbuf err = STRBUF_INIT;
2444
2445 if (check_refname_format(r->name, 0))
2446 return;
2447
2448 transaction = ref_transaction_begin(&err);
2449 if (!transaction ||
2450 ref_transaction_delete(transaction, r->name, r->sha1,
2451 REF_ISPRUNING, 1, &err) ||
2452 ref_transaction_commit(transaction, NULL, &err)) {
2453 ref_transaction_free(transaction);
2454 error("%s", err.buf);
2455 strbuf_release(&err);
2456 return;
2457 }
2458 ref_transaction_free(transaction);
2459 strbuf_release(&err);
2460 try_remove_empty_parents(r->name);
2461 }
2462
2463 static void prune_refs(struct ref_to_prune *r)
2464 {
2465 while (r) {
2466 prune_ref(r);
2467 r = r->next;
2468 }
2469 }
2470
2471 int pack_refs(unsigned int flags)
2472 {
2473 struct pack_refs_cb_data cbdata;
2474
2475 memset(&cbdata, 0, sizeof(cbdata));
2476 cbdata.flags = flags;
2477
2478 lock_packed_refs(LOCK_DIE_ON_ERROR);
2479 cbdata.packed_refs = get_packed_refs(&ref_cache);
2480
2481 do_for_each_entry_in_dir(get_loose_refs(&ref_cache), 0,
2482 pack_if_possible_fn, &cbdata);
2483
2484 if (commit_packed_refs())
2485 die_errno("unable to overwrite old ref-pack file");
2486
2487 prune_refs(cbdata.ref_to_prune);
2488 return 0;
2489 }
2490
2491 /*
2492 * If entry is no longer needed in packed-refs, add it to the string
2493 * list pointed to by cb_data. Reasons for deleting entries:
2494 *
2495 * - Entry is broken.
2496 * - Entry is overridden by a loose ref.
2497 * - Entry does not point at a valid object.
2498 *
2499 * In the first and third cases, also emit an error message because these
2500 * are indications of repository corruption.
2501 */
2502 static int curate_packed_ref_fn(struct ref_entry *entry, void *cb_data)
2503 {
2504 struct string_list *refs_to_delete = cb_data;
2505
2506 if (entry->flag & REF_ISBROKEN) {
2507 /* This shouldn't happen to packed refs. */
2508 error("%s is broken!", entry->name);
2509 string_list_append(refs_to_delete, entry->name);
2510 return 0;
2511 }
2512 if (!has_sha1_file(entry->u.value.sha1)) {
2513 unsigned char sha1[20];
2514 int flags;
2515
2516 if (read_ref_full(entry->name, sha1, 0, &flags))
2517 /* We should at least have found the packed ref. */
2518 die("Internal error");
2519 if ((flags & REF_ISSYMREF) || !(flags & REF_ISPACKED)) {
2520 /*
2521 * This packed reference is overridden by a
2522 * loose reference, so it is OK that its value
2523 * is no longer valid; for example, it might
2524 * refer to an object that has been garbage
2525 * collected. For this purpose we don't even
2526 * care whether the loose reference itself is
2527 * invalid, broken, symbolic, etc. Silently
2528 * remove the packed reference.
2529 */
2530 string_list_append(refs_to_delete, entry->name);
2531 return 0;
2532 }
2533 /*
2534 * There is no overriding loose reference, so the fact
2535 * that this reference doesn't refer to a valid object
2536 * indicates some kind of repository corruption.
2537 * Report the problem, then omit the reference from
2538 * the output.
2539 */
2540 error("%s does not point to a valid object!", entry->name);
2541 string_list_append(refs_to_delete, entry->name);
2542 return 0;
2543 }
2544
2545 return 0;
2546 }
2547
2548 int repack_without_refs(const char **refnames, int n, struct strbuf *err)
2549 {
2550 struct ref_dir *packed;
2551 struct string_list refs_to_delete = STRING_LIST_INIT_DUP;
2552 struct string_list_item *ref_to_delete;
2553 int i, ret, removed = 0;
2554
2555 /* Look for a packed ref */
2556 for (i = 0; i < n; i++)
2557 if (get_packed_ref(refnames[i]))
2558 break;
2559
2560 /* Avoid locking if we have nothing to do */
2561 if (i == n)
2562 return 0; /* no refname exists in packed refs */
2563
2564 if (lock_packed_refs(0)) {
2565 if (err) {
2566 unable_to_lock_message(git_path("packed-refs"), errno,
2567 err);
2568 return -1;
2569 }
2570 unable_to_lock_error(git_path("packed-refs"), errno);
2571 return error("cannot delete '%s' from packed refs", refnames[i]);
2572 }
2573 packed = get_packed_refs(&ref_cache);
2574
2575 /* Remove refnames from the cache */
2576 for (i = 0; i < n; i++)
2577 if (remove_entry(packed, refnames[i]) != -1)
2578 removed = 1;
2579 if (!removed) {
2580 /*
2581 * All packed entries disappeared while we were
2582 * acquiring the lock.
2583 */
2584 rollback_packed_refs();
2585 return 0;
2586 }
2587
2588 /* Remove any other accumulated cruft */
2589 do_for_each_entry_in_dir(packed, 0, curate_packed_ref_fn, &refs_to_delete);
2590 for_each_string_list_item(ref_to_delete, &refs_to_delete) {
2591 if (remove_entry(packed, ref_to_delete->string) == -1)
2592 die("internal error");
2593 }
2594
2595 /* Write what remains */
2596 ret = commit_packed_refs();
2597 if (ret && err)
2598 strbuf_addf(err, "unable to overwrite old ref-pack file: %s",
2599 strerror(errno));
2600 return ret;
2601 }
2602
2603 static int delete_ref_loose(struct ref_lock *lock, int flag)
2604 {
2605 if (!(flag & REF_ISPACKED) || flag & REF_ISSYMREF) {
2606 /*
2607 * loose. The loose file name is the same as the
2608 * lockfile name, minus ".lock":
2609 */
2610 char *loose_filename = get_locked_file_path(lock->lk);
2611 int err = unlink_or_warn(loose_filename);
2612 free(loose_filename);
2613 if (err && errno != ENOENT)
2614 return 1;
2615 }
2616 return 0;
2617 }
2618
2619 int delete_ref(const char *refname, const unsigned char *sha1, int delopt)
2620 {
2621 struct ref_transaction *transaction;
2622 struct strbuf err = STRBUF_INIT;
2623
2624 transaction = ref_transaction_begin(&err);
2625 if (!transaction ||
2626 ref_transaction_delete(transaction, refname, sha1, delopt,
2627 sha1 && !is_null_sha1(sha1), &err) ||
2628 ref_transaction_commit(transaction, NULL, &err)) {
2629 error("%s", err.buf);
2630 ref_transaction_free(transaction);
2631 strbuf_release(&err);
2632 return 1;
2633 }
2634 ref_transaction_free(transaction);
2635 strbuf_release(&err);
2636 return 0;
2637 }
2638
2639 /*
2640 * People using contrib's git-new-workdir have .git/logs/refs ->
2641 * /some/other/path/.git/logs/refs, and that may live on another device.
2642 *
2643 * IOW, to avoid cross device rename errors, the temporary renamed log must
2644 * live into logs/refs.
2645 */
2646 #define TMP_RENAMED_LOG "logs/refs/.tmp-renamed-log"
2647
2648 static int rename_tmp_log(const char *newrefname)
2649 {
2650 int attempts_remaining = 4;
2651
2652 retry:
2653 switch (safe_create_leading_directories(git_path("logs/%s", newrefname))) {
2654 case SCLD_OK:
2655 break; /* success */
2656 case SCLD_VANISHED:
2657 if (--attempts_remaining > 0)
2658 goto retry;
2659 /* fall through */
2660 default:
2661 error("unable to create directory for %s", newrefname);
2662 return -1;
2663 }
2664
2665 if (rename(git_path(TMP_RENAMED_LOG), git_path("logs/%s", newrefname))) {
2666 if ((errno==EISDIR || errno==ENOTDIR) && --attempts_remaining > 0) {
2667 /*
2668 * rename(a, b) when b is an existing
2669 * directory ought to result in ISDIR, but
2670 * Solaris 5.8 gives ENOTDIR. Sheesh.
2671 */
2672 if (remove_empty_directories(git_path("logs/%s", newrefname))) {
2673 error("Directory not empty: logs/%s", newrefname);
2674 return -1;
2675 }
2676 goto retry;
2677 } else if (errno == ENOENT && --attempts_remaining > 0) {
2678 /*
2679 * Maybe another process just deleted one of
2680 * the directories in the path to newrefname.
2681 * Try again from the beginning.
2682 */
2683 goto retry;
2684 } else {
2685 error("unable to move logfile "TMP_RENAMED_LOG" to logs/%s: %s",
2686 newrefname, strerror(errno));
2687 return -1;
2688 }
2689 }
2690 return 0;
2691 }
2692
2693 int rename_ref(const char *oldrefname, const char *newrefname, const char *logmsg)
2694 {
2695 unsigned char sha1[20], orig_sha1[20];
2696 int flag = 0, logmoved = 0;
2697 struct ref_lock *lock;
2698 struct stat loginfo;
2699 int log = !lstat(git_path("logs/%s", oldrefname), &loginfo);
2700 const char *symref = NULL;
2701
2702 if (log && S_ISLNK(loginfo.st_mode))
2703 return error("reflog for %s is a symlink", oldrefname);
2704
2705 symref = resolve_ref_unsafe(oldrefname, orig_sha1, 1, &flag);
2706 if (flag & REF_ISSYMREF)
2707 return error("refname %s is a symbolic ref, renaming it is not supported",
2708 oldrefname);
2709 if (!symref)
2710 return error("refname %s not found", oldrefname);
2711
2712 if (!is_refname_available(newrefname, oldrefname, get_packed_refs(&ref_cache)))
2713 return 1;
2714
2715 if (!is_refname_available(newrefname, oldrefname, get_loose_refs(&ref_cache)))
2716 return 1;
2717
2718 if (log && rename(git_path("logs/%s", oldrefname), git_path(TMP_RENAMED_LOG)))
2719 return error("unable to move logfile logs/%s to "TMP_RENAMED_LOG": %s",
2720 oldrefname, strerror(errno));
2721
2722 if (delete_ref(oldrefname, orig_sha1, REF_NODEREF)) {
2723 error("unable to delete old %s", oldrefname);
2724 goto rollback;
2725 }
2726
2727 if (!read_ref_full(newrefname, sha1, 1, &flag) &&
2728 delete_ref(newrefname, sha1, REF_NODEREF)) {
2729 if (errno==EISDIR) {
2730 if (remove_empty_directories(git_path("%s", newrefname))) {
2731 error("Directory not empty: %s", newrefname);
2732 goto rollback;
2733 }
2734 } else {
2735 error("unable to delete existing %s", newrefname);
2736 goto rollback;
2737 }
2738 }
2739
2740 if (log && rename_tmp_log(newrefname))
2741 goto rollback;
2742
2743 logmoved = log;
2744
2745 lock = lock_ref_sha1_basic(newrefname, NULL, 0, NULL);
2746 if (!lock) {
2747 error("unable to lock %s for update", newrefname);
2748 goto rollback;
2749 }
2750 lock->force_write = 1;
2751 hashcpy(lock->old_sha1, orig_sha1);
2752 if (write_ref_sha1(lock, orig_sha1, logmsg)) {
2753 error("unable to write current sha1 into %s", newrefname);
2754 goto rollback;
2755 }
2756
2757 return 0;
2758
2759 rollback:
2760 lock = lock_ref_sha1_basic(oldrefname, NULL, 0, NULL);
2761 if (!lock) {
2762 error("unable to lock %s for rollback", oldrefname);
2763 goto rollbacklog;
2764 }
2765
2766 lock->force_write = 1;
2767 flag = log_all_ref_updates;
2768 log_all_ref_updates = 0;
2769 if (write_ref_sha1(lock, orig_sha1, NULL))
2770 error("unable to write current sha1 into %s", oldrefname);
2771 log_all_ref_updates = flag;
2772
2773 rollbacklog:
2774 if (logmoved && rename(git_path("logs/%s", newrefname), git_path("logs/%s", oldrefname)))
2775 error("unable to restore logfile %s from %s: %s",
2776 oldrefname, newrefname, strerror(errno));
2777 if (!logmoved && log &&
2778 rename(git_path(TMP_RENAMED_LOG), git_path("logs/%s", oldrefname)))
2779 error("unable to restore logfile %s from "TMP_RENAMED_LOG": %s",
2780 oldrefname, strerror(errno));
2781
2782 return 1;
2783 }
2784
2785 int close_ref(struct ref_lock *lock)
2786 {
2787 if (close_lock_file(lock->lk))
2788 return -1;
2789 lock->lock_fd = -1;
2790 return 0;
2791 }
2792
2793 int commit_ref(struct ref_lock *lock)
2794 {
2795 if (commit_lock_file(lock->lk))
2796 return -1;
2797 lock->lock_fd = -1;
2798 return 0;
2799 }
2800
2801 void unlock_ref(struct ref_lock *lock)
2802 {
2803 /* Do not free lock->lk -- atexit() still looks at them */
2804 if (lock->lk)
2805 rollback_lock_file(lock->lk);
2806 free(lock->ref_name);
2807 free(lock->orig_ref_name);
2808 free(lock);
2809 }
2810
2811 /*
2812 * copy the reflog message msg to buf, which has been allocated sufficiently
2813 * large, while cleaning up the whitespaces. Especially, convert LF to space,
2814 * because reflog file is one line per entry.
2815 */
2816 static int copy_msg(char *buf, const char *msg)
2817 {
2818 char *cp = buf;
2819 char c;
2820 int wasspace = 1;
2821
2822 *cp++ = '\t';
2823 while ((c = *msg++)) {
2824 if (wasspace && isspace(c))
2825 continue;
2826 wasspace = isspace(c);
2827 if (wasspace)
2828 c = ' ';
2829 *cp++ = c;
2830 }
2831 while (buf < cp && isspace(cp[-1]))
2832 cp--;
2833 *cp++ = '\n';
2834 return cp - buf;
2835 }
2836
2837 /* This function must set a meaningful errno on failure */
2838 int log_ref_setup(const char *refname, char *logfile, int bufsize)
2839 {
2840 int logfd, oflags = O_APPEND | O_WRONLY;
2841
2842 git_snpath(logfile, bufsize, "logs/%s", refname);
2843 if (log_all_ref_updates &&
2844 (starts_with(refname, "refs/heads/") ||
2845 starts_with(refname, "refs/remotes/") ||
2846 starts_with(refname, "refs/notes/") ||
2847 !strcmp(refname, "HEAD"))) {
2848 if (safe_create_leading_directories(logfile) < 0) {
2849 int save_errno = errno;
2850 error("unable to create directory for %s", logfile);
2851 errno = save_errno;
2852 return -1;
2853 }
2854 oflags |= O_CREAT;
2855 }
2856
2857 logfd = open(logfile, oflags, 0666);
2858 if (logfd < 0) {
2859 if (!(oflags & O_CREAT) && errno == ENOENT)
2860 return 0;
2861
2862 if ((oflags & O_CREAT) && errno == EISDIR) {
2863 if (remove_empty_directories(logfile)) {
2864 int save_errno = errno;
2865 error("There are still logs under '%s'",
2866 logfile);
2867 errno = save_errno;
2868 return -1;
2869 }
2870 logfd = open(logfile, oflags, 0666);
2871 }
2872
2873 if (logfd < 0) {
2874 int save_errno = errno;
2875 error("Unable to append to %s: %s", logfile,
2876 strerror(errno));
2877 errno = save_errno;
2878 return -1;
2879 }
2880 }
2881
2882 adjust_shared_perm(logfile);
2883 close(logfd);
2884 return 0;
2885 }
2886
2887 static int log_ref_write(const char *refname, const unsigned char *old_sha1,
2888 const unsigned char *new_sha1, const char *msg)
2889 {
2890 int logfd, result, written, oflags = O_APPEND | O_WRONLY;
2891 unsigned maxlen, len;
2892 int msglen;
2893 char log_file[PATH_MAX];
2894 char *logrec;
2895 const char *committer;
2896
2897 if (log_all_ref_updates < 0)
2898 log_all_ref_updates = !is_bare_repository();
2899
2900 result = log_ref_setup(refname, log_file, sizeof(log_file));
2901 if (result)
2902 return result;
2903
2904 logfd = open(log_file, oflags);
2905 if (logfd < 0)
2906 return 0;
2907 msglen = msg ? strlen(msg) : 0;
2908 committer = git_committer_info(0);
2909 maxlen = strlen(committer) + msglen + 100;
2910 logrec = xmalloc(maxlen);
2911 len = sprintf(logrec, "%s %s %s\n",
2912 sha1_to_hex(old_sha1),
2913 sha1_to_hex(new_sha1),
2914 committer);
2915 if (msglen)
2916 len += copy_msg(logrec + len - 1, msg) - 1;
2917 written = len <= maxlen ? write_in_full(logfd, logrec, len) : -1;
2918 free(logrec);
2919 if (written != len) {
2920 int save_errno = errno;
2921 close(logfd);
2922 error("Unable to append to %s", log_file);
2923 errno = save_errno;
2924 return -1;
2925 }
2926 if (close(logfd)) {
2927 int save_errno = errno;
2928 error("Unable to append to %s", log_file);
2929 errno = save_errno;
2930 return -1;
2931 }
2932 return 0;
2933 }
2934
2935 int is_branch(const char *refname)
2936 {
2937 return !strcmp(refname, "HEAD") || starts_with(refname, "refs/heads/");
2938 }
2939
2940 /* This function must return a meaningful errno */
2941 int write_ref_sha1(struct ref_lock *lock,
2942 const unsigned char *sha1, const char *logmsg)
2943 {
2944 static char term = '\n';
2945 struct object *o;
2946
2947 if (!lock) {
2948 errno = EINVAL;
2949 return -1;
2950 }
2951 if (!lock->force_write && !hashcmp(lock->old_sha1, sha1)) {
2952 unlock_ref(lock);
2953 return 0;
2954 }
2955 o = parse_object(sha1);
2956 if (!o) {
2957 error("Trying to write ref %s with nonexistent object %s",
2958 lock->ref_name, sha1_to_hex(sha1));
2959 unlock_ref(lock);
2960 errno = EINVAL;
2961 return -1;
2962 }
2963 if (o->type != OBJ_COMMIT && is_branch(lock->ref_name)) {
2964 error("Trying to write non-commit object %s to branch %s",
2965 sha1_to_hex(sha1), lock->ref_name);
2966 unlock_ref(lock);
2967 errno = EINVAL;
2968 return -1;
2969 }
2970 if (write_in_full(lock->lock_fd, sha1_to_hex(sha1), 40) != 40 ||
2971 write_in_full(lock->lock_fd, &term, 1) != 1 ||
2972 close_ref(lock) < 0) {
2973 int save_errno = errno;
2974 error("Couldn't write %s", lock->lk->filename.buf);
2975 unlock_ref(lock);
2976 errno = save_errno;
2977 return -1;
2978 }
2979 clear_loose_ref_cache(&ref_cache);
2980 if (log_ref_write(lock->ref_name, lock->old_sha1, sha1, logmsg) < 0 ||
2981 (strcmp(lock->ref_name, lock->orig_ref_name) &&
2982 log_ref_write(lock->orig_ref_name, lock->old_sha1, sha1, logmsg) < 0)) {
2983 unlock_ref(lock);
2984 return -1;
2985 }
2986 if (strcmp(lock->orig_ref_name, "HEAD") != 0) {
2987 /*
2988 * Special hack: If a branch is updated directly and HEAD
2989 * points to it (may happen on the remote side of a push
2990 * for example) then logically the HEAD reflog should be
2991 * updated too.
2992 * A generic solution implies reverse symref information,
2993 * but finding all symrefs pointing to the given branch
2994 * would be rather costly for this rare event (the direct
2995 * update of a branch) to be worth it. So let's cheat and
2996 * check with HEAD only which should cover 99% of all usage
2997 * scenarios (even 100% of the default ones).
2998 */
2999 unsigned char head_sha1[20];
3000 int head_flag;
3001 const char *head_ref;
3002 head_ref = resolve_ref_unsafe("HEAD", head_sha1, 1, &head_flag);
3003 if (head_ref && (head_flag & REF_ISSYMREF) &&
3004 !strcmp(head_ref, lock->ref_name))
3005 log_ref_write("HEAD", lock->old_sha1, sha1, logmsg);
3006 }
3007 if (commit_ref(lock)) {
3008 error("Couldn't set %s", lock->ref_name);
3009 unlock_ref(lock);
3010 return -1;
3011 }
3012 unlock_ref(lock);
3013 return 0;
3014 }
3015
3016 int create_symref(const char *ref_target, const char *refs_heads_master,
3017 const char *logmsg)
3018 {
3019 const char *lockpath;
3020 char ref[1000];
3021 int fd, len, written;
3022 char *git_HEAD = git_pathdup("%s", ref_target);
3023 unsigned char old_sha1[20], new_sha1[20];
3024
3025 if (logmsg && read_ref(ref_target, old_sha1))
3026 hashclr(old_sha1);
3027
3028 if (safe_create_leading_directories(git_HEAD) < 0)
3029 return error("unable to create directory for %s", git_HEAD);
3030
3031 #ifndef NO_SYMLINK_HEAD
3032 if (prefer_symlink_refs) {
3033 unlink(git_HEAD);
3034 if (!symlink(refs_heads_master, git_HEAD))
3035 goto done;
3036 fprintf(stderr, "no symlink - falling back to symbolic ref\n");
3037 }
3038 #endif
3039
3040 len = snprintf(ref, sizeof(ref), "ref: %s\n", refs_heads_master);
3041 if (sizeof(ref) <= len) {
3042 error("refname too long: %s", refs_heads_master);
3043 goto error_free_return;
3044 }
3045 lockpath = mkpath("%s.lock", git_HEAD);
3046 fd = open(lockpath, O_CREAT | O_EXCL | O_WRONLY, 0666);
3047 if (fd < 0) {
3048 error("Unable to open %s for writing", lockpath);
3049 goto error_free_return;
3050 }
3051 written = write_in_full(fd, ref, len);
3052 if (close(fd) != 0 || written != len) {
3053 error("Unable to write to %s", lockpath);
3054 goto error_unlink_return;
3055 }
3056 if (rename(lockpath, git_HEAD) < 0) {
3057 error("Unable to create %s", git_HEAD);
3058 goto error_unlink_return;
3059 }
3060 if (adjust_shared_perm(git_HEAD)) {
3061 error("Unable to fix permissions on %s", lockpath);
3062 error_unlink_return:
3063 unlink_or_warn(lockpath);
3064 error_free_return:
3065 free(git_HEAD);
3066 return -1;
3067 }
3068
3069 #ifndef NO_SYMLINK_HEAD
3070 done:
3071 #endif
3072 if (logmsg && !read_ref(refs_heads_master, new_sha1))
3073 log_ref_write(ref_target, old_sha1, new_sha1, logmsg);
3074
3075 free(git_HEAD);
3076 return 0;
3077 }
3078
3079 struct read_ref_at_cb {
3080 const char *refname;
3081 unsigned long at_time;
3082 int cnt;
3083 int reccnt;
3084 unsigned char *sha1;
3085 int found_it;
3086
3087 unsigned char osha1[20];
3088 unsigned char nsha1[20];
3089 int tz;
3090 unsigned long date;
3091 char **msg;
3092 unsigned long *cutoff_time;
3093 int *cutoff_tz;
3094 int *cutoff_cnt;
3095 };
3096
3097 static int read_ref_at_ent(unsigned char *osha1, unsigned char *nsha1,
3098 const char *email, unsigned long timestamp, int tz,
3099 const char *message, void *cb_data)
3100 {
3101 struct read_ref_at_cb *cb = cb_data;
3102
3103 cb->reccnt++;
3104 cb->tz = tz;
3105 cb->date = timestamp;
3106
3107 if (timestamp <= cb->at_time || cb->cnt == 0) {
3108 if (cb->msg)
3109 *cb->msg = xstrdup(message);
3110 if (cb->cutoff_time)
3111 *cb->cutoff_time = timestamp;
3112 if (cb->cutoff_tz)
3113 *cb->cutoff_tz = tz;
3114 if (cb->cutoff_cnt)
3115 *cb->cutoff_cnt = cb->reccnt - 1;
3116 /*
3117 * we have not yet updated cb->[n|o]sha1 so they still
3118 * hold the values for the previous record.
3119 */
3120 if (!is_null_sha1(cb->osha1)) {
3121 hashcpy(cb->sha1, nsha1);
3122 if (hashcmp(cb->osha1, nsha1))
3123 warning("Log for ref %s has gap after %s.",
3124 cb->refname, show_date(cb->date, cb->tz, DATE_RFC2822));
3125 }
3126 else if (cb->date == cb->at_time)
3127 hashcpy(cb->sha1, nsha1);
3128 else if (hashcmp(nsha1, cb->sha1))
3129 warning("Log for ref %s unexpectedly ended on %s.",
3130 cb->refname, show_date(cb->date, cb->tz,
3131 DATE_RFC2822));
3132 hashcpy(cb->osha1, osha1);
3133 hashcpy(cb->nsha1, nsha1);
3134 cb->found_it = 1;
3135 return 1;
3136 }
3137 hashcpy(cb->osha1, osha1);
3138 hashcpy(cb->nsha1, nsha1);
3139 if (cb->cnt > 0)
3140 cb->cnt--;
3141 return 0;
3142 }
3143
3144 static int read_ref_at_ent_oldest(unsigned char *osha1, unsigned char *nsha1,
3145 const char *email, unsigned long timestamp,
3146 int tz, const char *message, void *cb_data)
3147 {
3148 struct read_ref_at_cb *cb = cb_data;
3149
3150 if (cb->msg)
3151 *cb->msg = xstrdup(message);
3152 if (cb->cutoff_time)
3153 *cb->cutoff_time = timestamp;
3154 if (cb->cutoff_tz)
3155 *cb->cutoff_tz = tz;
3156 if (cb->cutoff_cnt)
3157 *cb->cutoff_cnt = cb->reccnt;
3158 hashcpy(cb->sha1, osha1);
3159 if (is_null_sha1(cb->sha1))
3160 hashcpy(cb->sha1, nsha1);
3161 /* We just want the first entry */
3162 return 1;
3163 }
3164
3165 int read_ref_at(const char *refname, unsigned int flags, unsigned long at_time, int cnt,
3166 unsigned char *sha1, char **msg,
3167 unsigned long *cutoff_time, int *cutoff_tz, int *cutoff_cnt)
3168 {
3169 struct read_ref_at_cb cb;
3170
3171 memset(&cb, 0, sizeof(cb));
3172 cb.refname = refname;
3173 cb.at_time = at_time;
3174 cb.cnt = cnt;
3175 cb.msg = msg;
3176 cb.cutoff_time = cutoff_time;
3177 cb.cutoff_tz = cutoff_tz;
3178 cb.cutoff_cnt = cutoff_cnt;
3179 cb.sha1 = sha1;
3180
3181 for_each_reflog_ent_reverse(refname, read_ref_at_ent, &cb);
3182
3183 if (!cb.reccnt) {
3184 if (flags & GET_SHA1_QUIETLY)
3185 exit(128);
3186 else
3187 die("Log for %s is empty.", refname);
3188 }
3189 if (cb.found_it)
3190 return 0;
3191
3192 for_each_reflog_ent(refname, read_ref_at_ent_oldest, &cb);
3193
3194 return 1;
3195 }
3196
3197 int reflog_exists(const char *refname)
3198 {
3199 struct stat st;
3200
3201 return !lstat(git_path("logs/%s", refname), &st) &&
3202 S_ISREG(st.st_mode);
3203 }
3204
3205 int delete_reflog(const char *refname)
3206 {
3207 return remove_path(git_path("logs/%s", refname));
3208 }
3209
3210 static int show_one_reflog_ent(struct strbuf *sb, each_reflog_ent_fn fn, void *cb_data)
3211 {
3212 unsigned char osha1[20], nsha1[20];
3213 char *email_end, *message;
3214 unsigned long timestamp;
3215 int tz;
3216
3217 /* old SP new SP name <email> SP time TAB msg LF */
3218 if (sb->len < 83 || sb->buf[sb->len - 1] != '\n' ||
3219 get_sha1_hex(sb->buf, osha1) || sb->buf[40] != ' ' ||
3220 get_sha1_hex(sb->buf + 41, nsha1) || sb->buf[81] != ' ' ||
3221 !(email_end = strchr(sb->buf + 82, '>')) ||
3222 email_end[1] != ' ' ||
3223 !(timestamp = strtoul(email_end + 2, &message, 10)) ||
3224 !message || message[0] != ' ' ||
3225 (message[1] != '+' && message[1] != '-') ||
3226 !isdigit(message[2]) || !isdigit(message[3]) ||
3227 !isdigit(message[4]) || !isdigit(message[5]))
3228 return 0; /* corrupt? */
3229 email_end[1] = '\0';
3230 tz = strtol(message + 1, NULL, 10);
3231 if (message[6] != '\t')
3232 message += 6;
3233 else
3234 message += 7;
3235 return fn(osha1, nsha1, sb->buf + 82, timestamp, tz, message, cb_data);
3236 }
3237
3238 static char *find_beginning_of_line(char *bob, char *scan)
3239 {
3240 while (bob < scan && *(--scan) != '\n')
3241 ; /* keep scanning backwards */
3242 /*
3243 * Return either beginning of the buffer, or LF at the end of
3244 * the previous line.
3245 */
3246 return scan;
3247 }
3248
3249 int for_each_reflog_ent_reverse(const char *refname, each_reflog_ent_fn fn, void *cb_data)
3250 {
3251 struct strbuf sb = STRBUF_INIT;
3252 FILE *logfp;
3253 long pos;
3254 int ret = 0, at_tail = 1;
3255
3256 logfp = fopen(git_path("logs/%s", refname), "r");
3257 if (!logfp)
3258 return -1;
3259
3260 /* Jump to the end */
3261 if (fseek(logfp, 0, SEEK_END) < 0)
3262 return error("cannot seek back reflog for %s: %s",
3263 refname, strerror(errno));
3264 pos = ftell(logfp);
3265 while (!ret && 0 < pos) {
3266 int cnt;
3267 size_t nread;
3268 char buf[BUFSIZ];
3269 char *endp, *scanp;
3270
3271 /* Fill next block from the end */
3272 cnt = (sizeof(buf) < pos) ? sizeof(buf) : pos;
3273 if (fseek(logfp, pos - cnt, SEEK_SET))
3274 return error("cannot seek back reflog for %s: %s",
3275 refname, strerror(errno));
3276 nread = fread(buf, cnt, 1, logfp);
3277 if (nread != 1)
3278 return error("cannot read %d bytes from reflog for %s: %s",
3279 cnt, refname, strerror(errno));
3280 pos -= cnt;
3281
3282 scanp = endp = buf + cnt;
3283 if (at_tail && scanp[-1] == '\n')
3284 /* Looking at the final LF at the end of the file */
3285 scanp--;
3286 at_tail = 0;
3287
3288 while (buf < scanp) {
3289 /*
3290 * terminating LF of the previous line, or the beginning
3291 * of the buffer.
3292 */
3293 char *bp;
3294
3295 bp = find_beginning_of_line(buf, scanp);
3296
3297 if (*bp != '\n') {
3298 strbuf_splice(&sb, 0, 0, buf, endp - buf);
3299 if (pos)
3300 break; /* need to fill another block */
3301 scanp = buf - 1; /* leave loop */
3302 } else {
3303 /*
3304 * (bp + 1) thru endp is the beginning of the
3305 * current line we have in sb
3306 */
3307 strbuf_splice(&sb, 0, 0, bp + 1, endp - (bp + 1));
3308 scanp = bp;
3309 endp = bp + 1;
3310 }
3311 ret = show_one_reflog_ent(&sb, fn, cb_data);
3312 strbuf_reset(&sb);
3313 if (ret)
3314 break;
3315 }
3316
3317 }
3318 if (!ret && sb.len)
3319 ret = show_one_reflog_ent(&sb, fn, cb_data);
3320
3321 fclose(logfp);
3322 strbuf_release(&sb);
3323 return ret;
3324 }
3325
3326 int for_each_reflog_ent(const char *refname, each_reflog_ent_fn fn, void *cb_data)
3327 {
3328 FILE *logfp;
3329 struct strbuf sb = STRBUF_INIT;
3330 int ret = 0;
3331
3332 logfp = fopen(git_path("logs/%s", refname), "r");
3333 if (!logfp)
3334 return -1;
3335
3336 while (!ret && !strbuf_getwholeline(&sb, logfp, '\n'))
3337 ret = show_one_reflog_ent(&sb, fn, cb_data);
3338 fclose(logfp);
3339 strbuf_release(&sb);
3340 return ret;
3341 }
3342 /*
3343 * Call fn for each reflog in the namespace indicated by name. name
3344 * must be empty or end with '/'. Name will be used as a scratch
3345 * space, but its contents will be restored before return.
3346 */
3347 static int do_for_each_reflog(struct strbuf *name, each_ref_fn fn, void *cb_data)
3348 {
3349 DIR *d = opendir(git_path("logs/%s", name->buf));
3350 int retval = 0;
3351 struct dirent *de;
3352 int oldlen = name->len;
3353
3354 if (!d)
3355 return name->len ? errno : 0;
3356
3357 while ((de = readdir(d)) != NULL) {
3358 struct stat st;
3359
3360 if (de->d_name[0] == '.')
3361 continue;
3362 if (ends_with(de->d_name, ".lock"))
3363 continue;
3364 strbuf_addstr(name, de->d_name);
3365 if (stat(git_path("logs/%s", name->buf), &st) < 0) {
3366 ; /* silently ignore */
3367 } else {
3368 if (S_ISDIR(st.st_mode)) {
3369 strbuf_addch(name, '/');
3370 retval = do_for_each_reflog(name, fn, cb_data);
3371 } else {
3372 unsigned char sha1[20];
3373 if (read_ref_full(name->buf, sha1, 0, NULL))
3374 retval = error("bad ref for %s", name->buf);
3375 else
3376 retval = fn(name->buf, sha1, 0, cb_data);
3377 }
3378 if (retval)
3379 break;
3380 }
3381 strbuf_setlen(name, oldlen);
3382 }
3383 closedir(d);
3384 return retval;
3385 }
3386
3387 int for_each_reflog(each_ref_fn fn, void *cb_data)
3388 {
3389 int retval;
3390 struct strbuf name;
3391 strbuf_init(&name, PATH_MAX);
3392 retval = do_for_each_reflog(&name, fn, cb_data);
3393 strbuf_release(&name);
3394 return retval;
3395 }
3396
3397 /**
3398 * Information needed for a single ref update. Set new_sha1 to the
3399 * new value or to zero to delete the ref. To check the old value
3400 * while locking the ref, set have_old to 1 and set old_sha1 to the
3401 * value or to zero to ensure the ref does not exist before update.
3402 */
3403 struct ref_update {
3404 unsigned char new_sha1[20];
3405 unsigned char old_sha1[20];
3406 int flags; /* REF_NODEREF? */
3407 int have_old; /* 1 if old_sha1 is valid, 0 otherwise */
3408 struct ref_lock *lock;
3409 int type;
3410 const char refname[FLEX_ARRAY];
3411 };
3412
3413 /*
3414 * Transaction states.
3415 * OPEN: The transaction is in a valid state and can accept new updates.
3416 * An OPEN transaction can be committed.
3417 * CLOSED: A closed transaction is no longer active and no other operations
3418 * than free can be used on it in this state.
3419 * A transaction can either become closed by successfully committing
3420 * an active transaction or if there is a failure while building
3421 * the transaction thus rendering it failed/inactive.
3422 */
3423 enum ref_transaction_state {
3424 REF_TRANSACTION_OPEN = 0,
3425 REF_TRANSACTION_CLOSED = 1
3426 };
3427
3428 /*
3429 * Data structure for holding a reference transaction, which can
3430 * consist of checks and updates to multiple references, carried out
3431 * as atomically as possible. This structure is opaque to callers.
3432 */
3433 struct ref_transaction {
3434 struct ref_update **updates;
3435 size_t alloc;
3436 size_t nr;
3437 enum ref_transaction_state state;
3438 };
3439
3440 struct ref_transaction *ref_transaction_begin(struct strbuf *err)
3441 {
3442 return xcalloc(1, sizeof(struct ref_transaction));
3443 }
3444
3445 void ref_transaction_free(struct ref_transaction *transaction)
3446 {
3447 int i;
3448
3449 if (!transaction)
3450 return;
3451
3452 for (i = 0; i < transaction->nr; i++)
3453 free(transaction->updates[i]);
3454
3455 free(transaction->updates);
3456 free(transaction);
3457 }
3458
3459 static struct ref_update *add_update(struct ref_transaction *transaction,
3460 const char *refname)
3461 {
3462 size_t len = strlen(refname);
3463 struct ref_update *update = xcalloc(1, sizeof(*update) + len + 1);
3464
3465 strcpy((char *)update->refname, refname);
3466 ALLOC_GROW(transaction->updates, transaction->nr + 1, transaction->alloc);
3467 transaction->updates[transaction->nr++] = update;
3468 return update;
3469 }
3470
3471 int ref_transaction_update(struct ref_transaction *transaction,
3472 const char *refname,
3473 const unsigned char *new_sha1,
3474 const unsigned char *old_sha1,
3475 int flags, int have_old,
3476 struct strbuf *err)
3477 {
3478 struct ref_update *update;
3479
3480 if (transaction->state != REF_TRANSACTION_OPEN)
3481 die("BUG: update called for transaction that is not open");
3482
3483 if (have_old && !old_sha1)
3484 die("BUG: have_old is true but old_sha1 is NULL");
3485
3486 update = add_update(transaction, refname);
3487 hashcpy(update->new_sha1, new_sha1);
3488 update->flags = flags;
3489 update->have_old = have_old;
3490 if (have_old)
3491 hashcpy(update->old_sha1, old_sha1);
3492 return 0;
3493 }
3494
3495 int ref_transaction_create(struct ref_transaction *transaction,
3496 const char *refname,
3497 const unsigned char *new_sha1,
3498 int flags,
3499 struct strbuf *err)
3500 {
3501 struct ref_update *update;
3502
3503 if (transaction->state != REF_TRANSACTION_OPEN)
3504 die("BUG: create called for transaction that is not open");
3505
3506 if (!new_sha1 || is_null_sha1(new_sha1))
3507 die("BUG: create ref with null new_sha1");
3508
3509 update = add_update(transaction, refname);
3510
3511 hashcpy(update->new_sha1, new_sha1);
3512 hashclr(update->old_sha1);
3513 update->flags = flags;
3514 update->have_old = 1;
3515 return 0;
3516 }
3517
3518 int ref_transaction_delete(struct ref_transaction *transaction,
3519 const char *refname,
3520 const unsigned char *old_sha1,
3521 int flags, int have_old,
3522 struct strbuf *err)
3523 {
3524 struct ref_update *update;
3525
3526 if (transaction->state != REF_TRANSACTION_OPEN)
3527 die("BUG: delete called for transaction that is not open");
3528
3529 if (have_old && !old_sha1)
3530 die("BUG: have_old is true but old_sha1 is NULL");
3531
3532 update = add_update(transaction, refname);
3533 update->flags = flags;
3534 update->have_old = have_old;
3535 if (have_old) {
3536 assert(!is_null_sha1(old_sha1));
3537 hashcpy(update->old_sha1, old_sha1);
3538 }
3539 return 0;
3540 }
3541
3542 int update_ref(const char *action, const char *refname,
3543 const unsigned char *sha1, const unsigned char *oldval,
3544 int flags, enum action_on_err onerr)
3545 {
3546 struct ref_transaction *t;
3547 struct strbuf err = STRBUF_INIT;
3548
3549 t = ref_transaction_begin(&err);
3550 if (!t ||
3551 ref_transaction_update(t, refname, sha1, oldval, flags,
3552 !!oldval, &err) ||
3553 ref_transaction_commit(t, action, &err)) {
3554 const char *str = "update_ref failed for ref '%s': %s";
3555
3556 ref_transaction_free(t);
3557 switch (onerr) {
3558 case UPDATE_REFS_MSG_ON_ERR:
3559 error(str, refname, err.buf);
3560 break;
3561 case UPDATE_REFS_DIE_ON_ERR:
3562 die(str, refname, err.buf);
3563 break;
3564 case UPDATE_REFS_QUIET_ON_ERR:
3565 break;
3566 }
3567 strbuf_release(&err);
3568 return 1;
3569 }
3570 strbuf_release(&err);
3571 ref_transaction_free(t);
3572 return 0;
3573 }
3574
3575 static int ref_update_compare(const void *r1, const void *r2)
3576 {
3577 const struct ref_update * const *u1 = r1;
3578 const struct ref_update * const *u2 = r2;
3579 return strcmp((*u1)->refname, (*u2)->refname);
3580 }
3581
3582 static int ref_update_reject_duplicates(struct ref_update **updates, int n,
3583 struct strbuf *err)
3584 {
3585 int i;
3586 for (i = 1; i < n; i++)
3587 if (!strcmp(updates[i - 1]->refname, updates[i]->refname)) {
3588 const char *str =
3589 "Multiple updates for ref '%s' not allowed.";
3590 if (err)
3591 strbuf_addf(err, str, updates[i]->refname);
3592
3593 return 1;
3594 }
3595 return 0;
3596 }
3597
3598 int ref_transaction_commit(struct ref_transaction *transaction,
3599 const char *msg, struct strbuf *err)
3600 {
3601 int ret = 0, delnum = 0, i;
3602 const char **delnames;
3603 int n = transaction->nr;
3604 struct ref_update **updates = transaction->updates;
3605
3606 if (transaction->state != REF_TRANSACTION_OPEN)
3607 die("BUG: commit called for transaction that is not open");
3608
3609 if (!n) {
3610 transaction->state = REF_TRANSACTION_CLOSED;
3611 return 0;
3612 }
3613
3614 /* Allocate work space */
3615 delnames = xmalloc(sizeof(*delnames) * n);
3616
3617 /* Copy, sort, and reject duplicate refs */
3618 qsort(updates, n, sizeof(*updates), ref_update_compare);
3619 ret = ref_update_reject_duplicates(updates, n, err);
3620 if (ret)
3621 goto cleanup;
3622
3623 /* Acquire all locks while verifying old values */
3624 for (i = 0; i < n; i++) {
3625 struct ref_update *update = updates[i];
3626
3627 update->lock = lock_any_ref_for_update(update->refname,
3628 (update->have_old ?
3629 update->old_sha1 :
3630 NULL),
3631 update->flags,
3632 &update->type);
3633 if (!update->lock) {
3634 if (err)
3635 strbuf_addf(err, "Cannot lock the ref '%s'.",
3636 update->refname);
3637 ret = 1;
3638 goto cleanup;
3639 }
3640 }
3641
3642 /* Perform updates first so live commits remain referenced */
3643 for (i = 0; i < n; i++) {
3644 struct ref_update *update = updates[i];
3645
3646 if (!is_null_sha1(update->new_sha1)) {
3647 ret = write_ref_sha1(update->lock, update->new_sha1,
3648 msg);
3649 update->lock = NULL; /* freed by write_ref_sha1 */
3650 if (ret) {
3651 if (err)
3652 strbuf_addf(err, "Cannot update the ref '%s'.",
3653 update->refname);
3654 goto cleanup;
3655 }
3656 }
3657 }
3658
3659 /* Perform deletes now that updates are safely completed */
3660 for (i = 0; i < n; i++) {
3661 struct ref_update *update = updates[i];
3662
3663 if (update->lock) {
3664 ret |= delete_ref_loose(update->lock, update->type);
3665 if (!(update->flags & REF_ISPRUNING))
3666 delnames[delnum++] = update->lock->ref_name;
3667 }
3668 }
3669
3670 ret |= repack_without_refs(delnames, delnum, err);
3671 for (i = 0; i < delnum; i++)
3672 unlink_or_warn(git_path("logs/%s", delnames[i]));
3673 clear_loose_ref_cache(&ref_cache);
3674
3675 cleanup:
3676 transaction->state = REF_TRANSACTION_CLOSED;
3677
3678 for (i = 0; i < n; i++)
3679 if (updates[i]->lock)
3680 unlock_ref(updates[i]->lock);
3681 free(delnames);
3682 return ret;
3683 }
3684
3685 char *shorten_unambiguous_ref(const char *refname, int strict)
3686 {
3687 int i;
3688 static char **scanf_fmts;
3689 static int nr_rules;
3690 char *short_name;
3691
3692 if (!nr_rules) {
3693 /*
3694 * Pre-generate scanf formats from ref_rev_parse_rules[].
3695 * Generate a format suitable for scanf from a
3696 * ref_rev_parse_rules rule by interpolating "%s" at the
3697 * location of the "%.*s".
3698 */
3699 size_t total_len = 0;
3700 size_t offset = 0;
3701
3702 /* the rule list is NULL terminated, count them first */
3703 for (nr_rules = 0; ref_rev_parse_rules[nr_rules]; nr_rules++)
3704 /* -2 for strlen("%.*s") - strlen("%s"); +1 for NUL */
3705 total_len += strlen(ref_rev_parse_rules[nr_rules]) - 2 + 1;
3706
3707 scanf_fmts = xmalloc(nr_rules * sizeof(char *) + total_len);
3708
3709 offset = 0;
3710 for (i = 0; i < nr_rules; i++) {
3711 assert(offset < total_len);
3712 scanf_fmts[i] = (char *)&scanf_fmts[nr_rules] + offset;
3713 offset += snprintf(scanf_fmts[i], total_len - offset,
3714 ref_rev_parse_rules[i], 2, "%s") + 1;
3715 }
3716 }
3717
3718 /* bail out if there are no rules */
3719 if (!nr_rules)
3720 return xstrdup(refname);
3721
3722 /* buffer for scanf result, at most refname must fit */
3723 short_name = xstrdup(refname);
3724
3725 /* skip first rule, it will always match */
3726 for (i = nr_rules - 1; i > 0 ; --i) {
3727 int j;
3728 int rules_to_fail = i;
3729 int short_name_len;
3730
3731 if (1 != sscanf(refname, scanf_fmts[i], short_name))
3732 continue;
3733
3734 short_name_len = strlen(short_name);
3735
3736 /*
3737 * in strict mode, all (except the matched one) rules
3738 * must fail to resolve to a valid non-ambiguous ref
3739 */
3740 if (strict)
3741 rules_to_fail = nr_rules;
3742
3743 /*
3744 * check if the short name resolves to a valid ref,
3745 * but use only rules prior to the matched one
3746 */
3747 for (j = 0; j < rules_to_fail; j++) {
3748 const char *rule = ref_rev_parse_rules[j];
3749 char refname[PATH_MAX];
3750
3751 /* skip matched rule */
3752 if (i == j)
3753 continue;
3754
3755 /*
3756 * the short name is ambiguous, if it resolves
3757 * (with this previous rule) to a valid ref
3758 * read_ref() returns 0 on success
3759 */
3760 mksnpath(refname, sizeof(refname),
3761 rule, short_name_len, short_name);
3762 if (ref_exists(refname))
3763 break;
3764 }
3765
3766 /*
3767 * short name is non-ambiguous if all previous rules
3768 * haven't resolved to a valid ref
3769 */
3770 if (j == rules_to_fail)
3771 return short_name;
3772 }
3773
3774 free(short_name);
3775 return xstrdup(refname);
3776 }
3777
3778 static struct string_list *hide_refs;
3779
3780 int parse_hide_refs_config(const char *var, const char *value, const char *section)
3781 {
3782 if (!strcmp("transfer.hiderefs", var) ||
3783 /* NEEDSWORK: use parse_config_key() once both are merged */
3784 (starts_with(var, section) && var[strlen(section)] == '.' &&
3785 !strcmp(var + strlen(section), ".hiderefs"))) {
3786 char *ref;
3787 int len;
3788
3789 if (!value)
3790 return config_error_nonbool(var);
3791 ref = xstrdup(value);
3792 len = strlen(ref);
3793 while (len && ref[len - 1] == '/')
3794 ref[--len] = '\0';
3795 if (!hide_refs) {
3796 hide_refs = xcalloc(1, sizeof(*hide_refs));
3797 hide_refs->strdup_strings = 1;
3798 }
3799 string_list_append(hide_refs, ref);
3800 }
3801 return 0;
3802 }
3803
3804 int ref_is_hidden(const char *refname)
3805 {
3806 struct string_list_item *item;
3807
3808 if (!hide_refs)
3809 return 0;
3810 for_each_string_list_item(item, hide_refs) {
3811 int len;
3812 if (!starts_with(refname, item->string))
3813 continue;
3814 len = strlen(item->string);
3815 if (!refname[len] || refname[len] == '/')
3816 return 1;
3817 }
3818 return 0;
3819 }