9edf18b04e7e29b12fa3808aab2239efcc404dca
[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 return -1; /* Component starts with '.'. */
75 if (cp - refname >= LOCK_SUFFIX_LEN &&
76 !memcmp(cp - LOCK_SUFFIX_LEN, LOCK_SUFFIX, LOCK_SUFFIX_LEN))
77 return -1; /* Refname ends with ".lock". */
78 return cp - refname;
79 }
80
81 int check_refname_format(const char *refname, int flags)
82 {
83 int component_len, component_count = 0;
84
85 if (!strcmp(refname, "@"))
86 /* Refname is a single character '@'. */
87 return -1;
88
89 while (1) {
90 /* We are at the start of a path component. */
91 component_len = check_refname_component(refname, flags);
92 if (component_len <= 0) {
93 if ((flags & REFNAME_REFSPEC_PATTERN) &&
94 refname[0] == '*' &&
95 (refname[1] == '\0' || refname[1] == '/')) {
96 /* Accept one wildcard as a full refname component. */
97 flags &= ~REFNAME_REFSPEC_PATTERN;
98 component_len = 1;
99 } else {
100 return -1;
101 }
102 }
103 component_count++;
104 if (refname[component_len] == '\0')
105 break;
106 /* Skip to next component. */
107 refname += component_len + 1;
108 }
109
110 if (refname[component_len - 1] == '.')
111 return -1; /* Refname ends with '.'. */
112 if (!(flags & REFNAME_ALLOW_ONELEVEL) && component_count < 2)
113 return -1; /* Refname has only one component. */
114 return 0;
115 }
116
117 struct ref_entry;
118
119 /*
120 * Information used (along with the information in ref_entry) to
121 * describe a single cached reference. This data structure only
122 * occurs embedded in a union in struct ref_entry, and only when
123 * (ref_entry->flag & REF_DIR) is zero.
124 */
125 struct ref_value {
126 /*
127 * The name of the object to which this reference resolves
128 * (which may be a tag object). If REF_ISBROKEN, this is
129 * null. If REF_ISSYMREF, then this is the name of the object
130 * referred to by the last reference in the symlink chain.
131 */
132 unsigned char sha1[20];
133
134 /*
135 * If REF_KNOWS_PEELED, then this field holds the peeled value
136 * of this reference, or null if the reference is known not to
137 * be peelable. See the documentation for peel_ref() for an
138 * exact definition of "peelable".
139 */
140 unsigned char peeled[20];
141 };
142
143 struct ref_cache;
144
145 /*
146 * Information used (along with the information in ref_entry) to
147 * describe a level in the hierarchy of references. This data
148 * structure only occurs embedded in a union in struct ref_entry, and
149 * only when (ref_entry.flag & REF_DIR) is set. In that case,
150 * (ref_entry.flag & REF_INCOMPLETE) determines whether the references
151 * in the directory have already been read:
152 *
153 * (ref_entry.flag & REF_INCOMPLETE) unset -- a directory of loose
154 * or packed references, already read.
155 *
156 * (ref_entry.flag & REF_INCOMPLETE) set -- a directory of loose
157 * references that hasn't been read yet (nor has any of its
158 * subdirectories).
159 *
160 * Entries within a directory are stored within a growable array of
161 * pointers to ref_entries (entries, nr, alloc). Entries 0 <= i <
162 * sorted are sorted by their component name in strcmp() order and the
163 * remaining entries are unsorted.
164 *
165 * Loose references are read lazily, one directory at a time. When a
166 * directory of loose references is read, then all of the references
167 * in that directory are stored, and REF_INCOMPLETE stubs are created
168 * for any subdirectories, but the subdirectories themselves are not
169 * read. The reading is triggered by get_ref_dir().
170 */
171 struct ref_dir {
172 int nr, alloc;
173
174 /*
175 * Entries with index 0 <= i < sorted are sorted by name. New
176 * entries are appended to the list unsorted, and are sorted
177 * only when required; thus we avoid the need to sort the list
178 * after the addition of every reference.
179 */
180 int sorted;
181
182 /* A pointer to the ref_cache that contains this ref_dir. */
183 struct ref_cache *ref_cache;
184
185 struct ref_entry **entries;
186 };
187
188 /*
189 * Bit values for ref_entry::flag. REF_ISSYMREF=0x01,
190 * REF_ISPACKED=0x02, REF_ISBROKEN=0x04 and REF_BAD_NAME=0x08 are
191 * public values; see refs.h.
192 */
193
194 /*
195 * The field ref_entry->u.value.peeled of this value entry contains
196 * the correct peeled value for the reference, which might be
197 * null_sha1 if the reference is not a tag or if it is broken.
198 */
199 #define REF_KNOWS_PEELED 0x10
200
201 /* ref_entry represents a directory of references */
202 #define REF_DIR 0x20
203
204 /*
205 * Entry has not yet been read from disk (used only for REF_DIR
206 * entries representing loose references)
207 */
208 #define REF_INCOMPLETE 0x40
209
210 /*
211 * A ref_entry represents either a reference or a "subdirectory" of
212 * references.
213 *
214 * Each directory in the reference namespace is represented by a
215 * ref_entry with (flags & REF_DIR) set and containing a subdir member
216 * that holds the entries in that directory that have been read so
217 * far. If (flags & REF_INCOMPLETE) is set, then the directory and
218 * its subdirectories haven't been read yet. REF_INCOMPLETE is only
219 * used for loose reference directories.
220 *
221 * References are represented by a ref_entry with (flags & REF_DIR)
222 * unset and a value member that describes the reference's value. The
223 * flag member is at the ref_entry level, but it is also needed to
224 * interpret the contents of the value field (in other words, a
225 * ref_value object is not very much use without the enclosing
226 * ref_entry).
227 *
228 * Reference names cannot end with slash and directories' names are
229 * always stored with a trailing slash (except for the top-level
230 * directory, which is always denoted by ""). This has two nice
231 * consequences: (1) when the entries in each subdir are sorted
232 * lexicographically by name (as they usually are), the references in
233 * a whole tree can be generated in lexicographic order by traversing
234 * the tree in left-to-right, depth-first order; (2) the names of
235 * references and subdirectories cannot conflict, and therefore the
236 * presence of an empty subdirectory does not block the creation of a
237 * similarly-named reference. (The fact that reference names with the
238 * same leading components can conflict *with each other* is a
239 * separate issue that is regulated by is_refname_available().)
240 *
241 * Please note that the name field contains the fully-qualified
242 * reference (or subdirectory) name. Space could be saved by only
243 * storing the relative names. But that would require the full names
244 * to be generated on the fly when iterating in do_for_each_ref(), and
245 * would break callback functions, who have always been able to assume
246 * that the name strings that they are passed will not be freed during
247 * the iteration.
248 */
249 struct ref_entry {
250 unsigned char flag; /* ISSYMREF? ISPACKED? */
251 union {
252 struct ref_value value; /* if not (flags&REF_DIR) */
253 struct ref_dir subdir; /* if (flags&REF_DIR) */
254 } u;
255 /*
256 * The full name of the reference (e.g., "refs/heads/master")
257 * or the full name of the directory with a trailing slash
258 * (e.g., "refs/heads/"):
259 */
260 char name[FLEX_ARRAY];
261 };
262
263 static void read_loose_refs(const char *dirname, struct ref_dir *dir);
264
265 static struct ref_dir *get_ref_dir(struct ref_entry *entry)
266 {
267 struct ref_dir *dir;
268 assert(entry->flag & REF_DIR);
269 dir = &entry->u.subdir;
270 if (entry->flag & REF_INCOMPLETE) {
271 read_loose_refs(entry->name, dir);
272 entry->flag &= ~REF_INCOMPLETE;
273 }
274 return dir;
275 }
276
277 /*
278 * Check if a refname is safe.
279 * For refs that start with "refs/" we consider it safe as long they do
280 * not try to resolve to outside of refs/.
281 *
282 * For all other refs we only consider them safe iff they only contain
283 * upper case characters and '_' (like "HEAD" AND "MERGE_HEAD", and not like
284 * "config").
285 */
286 static int refname_is_safe(const char *refname)
287 {
288 if (starts_with(refname, "refs/")) {
289 char *buf;
290 int result;
291
292 buf = xmalloc(strlen(refname) + 1);
293 /*
294 * Does the refname try to escape refs/?
295 * For example: refs/foo/../bar is safe but refs/foo/../../bar
296 * is not.
297 */
298 result = !normalize_path_copy(buf, refname + strlen("refs/"));
299 free(buf);
300 return result;
301 }
302 while (*refname) {
303 if (!isupper(*refname) && *refname != '_')
304 return 0;
305 refname++;
306 }
307 return 1;
308 }
309
310 static struct ref_entry *create_ref_entry(const char *refname,
311 const unsigned char *sha1, int flag,
312 int check_name)
313 {
314 int len;
315 struct ref_entry *ref;
316
317 if (check_name &&
318 check_refname_format(refname, REFNAME_ALLOW_ONELEVEL))
319 die("Reference has invalid format: '%s'", refname);
320 if (!check_name && !refname_is_safe(refname))
321 die("Reference has invalid name: '%s'", refname);
322 len = strlen(refname) + 1;
323 ref = xmalloc(sizeof(struct ref_entry) + len);
324 hashcpy(ref->u.value.sha1, sha1);
325 hashclr(ref->u.value.peeled);
326 memcpy(ref->name, refname, len);
327 ref->flag = flag;
328 return ref;
329 }
330
331 static void clear_ref_dir(struct ref_dir *dir);
332
333 static void free_ref_entry(struct ref_entry *entry)
334 {
335 if (entry->flag & REF_DIR) {
336 /*
337 * Do not use get_ref_dir() here, as that might
338 * trigger the reading of loose refs.
339 */
340 clear_ref_dir(&entry->u.subdir);
341 }
342 free(entry);
343 }
344
345 /*
346 * Add a ref_entry to the end of dir (unsorted). Entry is always
347 * stored directly in dir; no recursion into subdirectories is
348 * done.
349 */
350 static void add_entry_to_dir(struct ref_dir *dir, struct ref_entry *entry)
351 {
352 ALLOC_GROW(dir->entries, dir->nr + 1, dir->alloc);
353 dir->entries[dir->nr++] = entry;
354 /* optimize for the case that entries are added in order */
355 if (dir->nr == 1 ||
356 (dir->nr == dir->sorted + 1 &&
357 strcmp(dir->entries[dir->nr - 2]->name,
358 dir->entries[dir->nr - 1]->name) < 0))
359 dir->sorted = dir->nr;
360 }
361
362 /*
363 * Clear and free all entries in dir, recursively.
364 */
365 static void clear_ref_dir(struct ref_dir *dir)
366 {
367 int i;
368 for (i = 0; i < dir->nr; i++)
369 free_ref_entry(dir->entries[i]);
370 free(dir->entries);
371 dir->sorted = dir->nr = dir->alloc = 0;
372 dir->entries = NULL;
373 }
374
375 /*
376 * Create a struct ref_entry object for the specified dirname.
377 * dirname is the name of the directory with a trailing slash (e.g.,
378 * "refs/heads/") or "" for the top-level directory.
379 */
380 static struct ref_entry *create_dir_entry(struct ref_cache *ref_cache,
381 const char *dirname, size_t len,
382 int incomplete)
383 {
384 struct ref_entry *direntry;
385 direntry = xcalloc(1, sizeof(struct ref_entry) + len + 1);
386 memcpy(direntry->name, dirname, len);
387 direntry->name[len] = '\0';
388 direntry->u.subdir.ref_cache = ref_cache;
389 direntry->flag = REF_DIR | (incomplete ? REF_INCOMPLETE : 0);
390 return direntry;
391 }
392
393 static int ref_entry_cmp(const void *a, const void *b)
394 {
395 struct ref_entry *one = *(struct ref_entry **)a;
396 struct ref_entry *two = *(struct ref_entry **)b;
397 return strcmp(one->name, two->name);
398 }
399
400 static void sort_ref_dir(struct ref_dir *dir);
401
402 struct string_slice {
403 size_t len;
404 const char *str;
405 };
406
407 static int ref_entry_cmp_sslice(const void *key_, const void *ent_)
408 {
409 const struct string_slice *key = key_;
410 const struct ref_entry *ent = *(const struct ref_entry * const *)ent_;
411 int cmp = strncmp(key->str, ent->name, key->len);
412 if (cmp)
413 return cmp;
414 return '\0' - (unsigned char)ent->name[key->len];
415 }
416
417 /*
418 * Return the index of the entry with the given refname from the
419 * ref_dir (non-recursively), sorting dir if necessary. Return -1 if
420 * no such entry is found. dir must already be complete.
421 */
422 static int search_ref_dir(struct ref_dir *dir, const char *refname, size_t len)
423 {
424 struct ref_entry **r;
425 struct string_slice key;
426
427 if (refname == NULL || !dir->nr)
428 return -1;
429
430 sort_ref_dir(dir);
431 key.len = len;
432 key.str = refname;
433 r = bsearch(&key, dir->entries, dir->nr, sizeof(*dir->entries),
434 ref_entry_cmp_sslice);
435
436 if (r == NULL)
437 return -1;
438
439 return r - dir->entries;
440 }
441
442 /*
443 * Search for a directory entry directly within dir (without
444 * recursing). Sort dir if necessary. subdirname must be a directory
445 * name (i.e., end in '/'). If mkdir is set, then create the
446 * directory if it is missing; otherwise, return NULL if the desired
447 * directory cannot be found. dir must already be complete.
448 */
449 static struct ref_dir *search_for_subdir(struct ref_dir *dir,
450 const char *subdirname, size_t len,
451 int mkdir)
452 {
453 int entry_index = search_ref_dir(dir, subdirname, len);
454 struct ref_entry *entry;
455 if (entry_index == -1) {
456 if (!mkdir)
457 return NULL;
458 /*
459 * Since dir is complete, the absence of a subdir
460 * means that the subdir really doesn't exist;
461 * therefore, create an empty record for it but mark
462 * the record complete.
463 */
464 entry = create_dir_entry(dir->ref_cache, subdirname, len, 0);
465 add_entry_to_dir(dir, entry);
466 } else {
467 entry = dir->entries[entry_index];
468 }
469 return get_ref_dir(entry);
470 }
471
472 /*
473 * If refname is a reference name, find the ref_dir within the dir
474 * tree that should hold refname. If refname is a directory name
475 * (i.e., ends in '/'), then return that ref_dir itself. dir must
476 * represent the top-level directory and must already be complete.
477 * Sort ref_dirs and recurse into subdirectories as necessary. If
478 * mkdir is set, then create any missing directories; otherwise,
479 * return NULL if the desired directory cannot be found.
480 */
481 static struct ref_dir *find_containing_dir(struct ref_dir *dir,
482 const char *refname, int mkdir)
483 {
484 const char *slash;
485 for (slash = strchr(refname, '/'); slash; slash = strchr(slash + 1, '/')) {
486 size_t dirnamelen = slash - refname + 1;
487 struct ref_dir *subdir;
488 subdir = search_for_subdir(dir, refname, dirnamelen, mkdir);
489 if (!subdir) {
490 dir = NULL;
491 break;
492 }
493 dir = subdir;
494 }
495
496 return dir;
497 }
498
499 /*
500 * Find the value entry with the given name in dir, sorting ref_dirs
501 * and recursing into subdirectories as necessary. If the name is not
502 * found or it corresponds to a directory entry, return NULL.
503 */
504 static struct ref_entry *find_ref(struct ref_dir *dir, const char *refname)
505 {
506 int entry_index;
507 struct ref_entry *entry;
508 dir = find_containing_dir(dir, refname, 0);
509 if (!dir)
510 return NULL;
511 entry_index = search_ref_dir(dir, refname, strlen(refname));
512 if (entry_index == -1)
513 return NULL;
514 entry = dir->entries[entry_index];
515 return (entry->flag & REF_DIR) ? NULL : entry;
516 }
517
518 /*
519 * Remove the entry with the given name from dir, recursing into
520 * subdirectories as necessary. If refname is the name of a directory
521 * (i.e., ends with '/'), then remove the directory and its contents.
522 * If the removal was successful, return the number of entries
523 * remaining in the directory entry that contained the deleted entry.
524 * If the name was not found, return -1. Please note that this
525 * function only deletes the entry from the cache; it does not delete
526 * it from the filesystem or ensure that other cache entries (which
527 * might be symbolic references to the removed entry) are updated.
528 * Nor does it remove any containing dir entries that might be made
529 * empty by the removal. dir must represent the top-level directory
530 * and must already be complete.
531 */
532 static int remove_entry(struct ref_dir *dir, const char *refname)
533 {
534 int refname_len = strlen(refname);
535 int entry_index;
536 struct ref_entry *entry;
537 int is_dir = refname[refname_len - 1] == '/';
538 if (is_dir) {
539 /*
540 * refname represents a reference directory. Remove
541 * the trailing slash; otherwise we will get the
542 * directory *representing* refname rather than the
543 * one *containing* it.
544 */
545 char *dirname = xmemdupz(refname, refname_len - 1);
546 dir = find_containing_dir(dir, dirname, 0);
547 free(dirname);
548 } else {
549 dir = find_containing_dir(dir, refname, 0);
550 }
551 if (!dir)
552 return -1;
553 entry_index = search_ref_dir(dir, refname, refname_len);
554 if (entry_index == -1)
555 return -1;
556 entry = dir->entries[entry_index];
557
558 memmove(&dir->entries[entry_index],
559 &dir->entries[entry_index + 1],
560 (dir->nr - entry_index - 1) * sizeof(*dir->entries)
561 );
562 dir->nr--;
563 if (dir->sorted > entry_index)
564 dir->sorted--;
565 free_ref_entry(entry);
566 return dir->nr;
567 }
568
569 /*
570 * Add a ref_entry to the ref_dir (unsorted), recursing into
571 * subdirectories as necessary. dir must represent the top-level
572 * directory. Return 0 on success.
573 */
574 static int add_ref(struct ref_dir *dir, struct ref_entry *ref)
575 {
576 dir = find_containing_dir(dir, ref->name, 1);
577 if (!dir)
578 return -1;
579 add_entry_to_dir(dir, ref);
580 return 0;
581 }
582
583 /*
584 * Emit a warning and return true iff ref1 and ref2 have the same name
585 * and the same sha1. Die if they have the same name but different
586 * sha1s.
587 */
588 static int is_dup_ref(const struct ref_entry *ref1, const struct ref_entry *ref2)
589 {
590 if (strcmp(ref1->name, ref2->name))
591 return 0;
592
593 /* Duplicate name; make sure that they don't conflict: */
594
595 if ((ref1->flag & REF_DIR) || (ref2->flag & REF_DIR))
596 /* This is impossible by construction */
597 die("Reference directory conflict: %s", ref1->name);
598
599 if (hashcmp(ref1->u.value.sha1, ref2->u.value.sha1))
600 die("Duplicated ref, and SHA1s don't match: %s", ref1->name);
601
602 warning("Duplicated ref: %s", ref1->name);
603 return 1;
604 }
605
606 /*
607 * Sort the entries in dir non-recursively (if they are not already
608 * sorted) and remove any duplicate entries.
609 */
610 static void sort_ref_dir(struct ref_dir *dir)
611 {
612 int i, j;
613 struct ref_entry *last = NULL;
614
615 /*
616 * This check also prevents passing a zero-length array to qsort(),
617 * which is a problem on some platforms.
618 */
619 if (dir->sorted == dir->nr)
620 return;
621
622 qsort(dir->entries, dir->nr, sizeof(*dir->entries), ref_entry_cmp);
623
624 /* Remove any duplicates: */
625 for (i = 0, j = 0; j < dir->nr; j++) {
626 struct ref_entry *entry = dir->entries[j];
627 if (last && is_dup_ref(last, entry))
628 free_ref_entry(entry);
629 else
630 last = dir->entries[i++] = entry;
631 }
632 dir->sorted = dir->nr = i;
633 }
634
635 /* Include broken references in a do_for_each_ref*() iteration: */
636 #define DO_FOR_EACH_INCLUDE_BROKEN 0x01
637
638 /*
639 * Return true iff the reference described by entry can be resolved to
640 * an object in the database. Emit a warning if the referred-to
641 * object does not exist.
642 */
643 static int ref_resolves_to_object(struct ref_entry *entry)
644 {
645 if (entry->flag & REF_ISBROKEN)
646 return 0;
647 if (!has_sha1_file(entry->u.value.sha1)) {
648 error("%s does not point to a valid object!", entry->name);
649 return 0;
650 }
651 return 1;
652 }
653
654 /*
655 * current_ref is a performance hack: when iterating over references
656 * using the for_each_ref*() functions, current_ref is set to the
657 * current reference's entry before calling the callback function. If
658 * the callback function calls peel_ref(), then peel_ref() first
659 * checks whether the reference to be peeled is the current reference
660 * (it usually is) and if so, returns that reference's peeled version
661 * if it is available. This avoids a refname lookup in a common case.
662 */
663 static struct ref_entry *current_ref;
664
665 typedef int each_ref_entry_fn(struct ref_entry *entry, void *cb_data);
666
667 struct ref_entry_cb {
668 const char *base;
669 int trim;
670 int flags;
671 each_ref_fn *fn;
672 void *cb_data;
673 };
674
675 /*
676 * Handle one reference in a do_for_each_ref*()-style iteration,
677 * calling an each_ref_fn for each entry.
678 */
679 static int do_one_ref(struct ref_entry *entry, void *cb_data)
680 {
681 struct ref_entry_cb *data = cb_data;
682 struct ref_entry *old_current_ref;
683 int retval;
684
685 if (!starts_with(entry->name, data->base))
686 return 0;
687
688 if (!(data->flags & DO_FOR_EACH_INCLUDE_BROKEN) &&
689 !ref_resolves_to_object(entry))
690 return 0;
691
692 /* Store the old value, in case this is a recursive call: */
693 old_current_ref = current_ref;
694 current_ref = entry;
695 retval = data->fn(entry->name + data->trim, entry->u.value.sha1,
696 entry->flag, data->cb_data);
697 current_ref = old_current_ref;
698 return retval;
699 }
700
701 /*
702 * Call fn for each reference in dir that has index in the range
703 * offset <= index < dir->nr. Recurse into subdirectories that are in
704 * that index range, sorting them before iterating. This function
705 * does not sort dir itself; it should be sorted beforehand. fn is
706 * called for all references, including broken ones.
707 */
708 static int do_for_each_entry_in_dir(struct ref_dir *dir, int offset,
709 each_ref_entry_fn fn, void *cb_data)
710 {
711 int i;
712 assert(dir->sorted == dir->nr);
713 for (i = offset; i < dir->nr; i++) {
714 struct ref_entry *entry = dir->entries[i];
715 int retval;
716 if (entry->flag & REF_DIR) {
717 struct ref_dir *subdir = get_ref_dir(entry);
718 sort_ref_dir(subdir);
719 retval = do_for_each_entry_in_dir(subdir, 0, fn, cb_data);
720 } else {
721 retval = fn(entry, cb_data);
722 }
723 if (retval)
724 return retval;
725 }
726 return 0;
727 }
728
729 /*
730 * Call fn for each reference in the union of dir1 and dir2, in order
731 * by refname. Recurse into subdirectories. If a value entry appears
732 * in both dir1 and dir2, then only process the version that is in
733 * dir2. The input dirs must already be sorted, but subdirs will be
734 * sorted as needed. fn is called for all references, including
735 * broken ones.
736 */
737 static int do_for_each_entry_in_dirs(struct ref_dir *dir1,
738 struct ref_dir *dir2,
739 each_ref_entry_fn fn, void *cb_data)
740 {
741 int retval;
742 int i1 = 0, i2 = 0;
743
744 assert(dir1->sorted == dir1->nr);
745 assert(dir2->sorted == dir2->nr);
746 while (1) {
747 struct ref_entry *e1, *e2;
748 int cmp;
749 if (i1 == dir1->nr) {
750 return do_for_each_entry_in_dir(dir2, i2, fn, cb_data);
751 }
752 if (i2 == dir2->nr) {
753 return do_for_each_entry_in_dir(dir1, i1, fn, cb_data);
754 }
755 e1 = dir1->entries[i1];
756 e2 = dir2->entries[i2];
757 cmp = strcmp(e1->name, e2->name);
758 if (cmp == 0) {
759 if ((e1->flag & REF_DIR) && (e2->flag & REF_DIR)) {
760 /* Both are directories; descend them in parallel. */
761 struct ref_dir *subdir1 = get_ref_dir(e1);
762 struct ref_dir *subdir2 = get_ref_dir(e2);
763 sort_ref_dir(subdir1);
764 sort_ref_dir(subdir2);
765 retval = do_for_each_entry_in_dirs(
766 subdir1, subdir2, fn, cb_data);
767 i1++;
768 i2++;
769 } else if (!(e1->flag & REF_DIR) && !(e2->flag & REF_DIR)) {
770 /* Both are references; ignore the one from dir1. */
771 retval = fn(e2, cb_data);
772 i1++;
773 i2++;
774 } else {
775 die("conflict between reference and directory: %s",
776 e1->name);
777 }
778 } else {
779 struct ref_entry *e;
780 if (cmp < 0) {
781 e = e1;
782 i1++;
783 } else {
784 e = e2;
785 i2++;
786 }
787 if (e->flag & REF_DIR) {
788 struct ref_dir *subdir = get_ref_dir(e);
789 sort_ref_dir(subdir);
790 retval = do_for_each_entry_in_dir(
791 subdir, 0, fn, cb_data);
792 } else {
793 retval = fn(e, cb_data);
794 }
795 }
796 if (retval)
797 return retval;
798 }
799 }
800
801 /*
802 * Load all of the refs from the dir into our in-memory cache. The hard work
803 * of loading loose refs is done by get_ref_dir(), so we just need to recurse
804 * through all of the sub-directories. We do not even need to care about
805 * sorting, as traversal order does not matter to us.
806 */
807 static void prime_ref_dir(struct ref_dir *dir)
808 {
809 int i;
810 for (i = 0; i < dir->nr; i++) {
811 struct ref_entry *entry = dir->entries[i];
812 if (entry->flag & REF_DIR)
813 prime_ref_dir(get_ref_dir(entry));
814 }
815 }
816
817 static int entry_matches(struct ref_entry *entry, const struct string_list *list)
818 {
819 return list && string_list_has_string(list, entry->name);
820 }
821
822 struct nonmatching_ref_data {
823 const struct string_list *skip;
824 struct ref_entry *found;
825 };
826
827 static int nonmatching_ref_fn(struct ref_entry *entry, void *vdata)
828 {
829 struct nonmatching_ref_data *data = vdata;
830
831 if (entry_matches(entry, data->skip))
832 return 0;
833
834 data->found = entry;
835 return 1;
836 }
837
838 static void report_refname_conflict(struct ref_entry *entry,
839 const char *refname)
840 {
841 error("'%s' exists; cannot create '%s'", entry->name, refname);
842 }
843
844 /*
845 * Return true iff a reference named refname could be created without
846 * conflicting with the name of an existing reference in dir. If
847 * skip is non-NULL, ignore potential conflicts with refs in skip
848 * (e.g., because they are scheduled for deletion in the same
849 * operation).
850 *
851 * Two reference names conflict if one of them exactly matches the
852 * leading components of the other; e.g., "foo/bar" conflicts with
853 * both "foo" and with "foo/bar/baz" but not with "foo/bar" or
854 * "foo/barbados".
855 *
856 * skip must be sorted.
857 */
858 static int is_refname_available(const char *refname,
859 const struct string_list *skip,
860 struct ref_dir *dir)
861 {
862 const char *slash;
863 size_t len;
864 int pos;
865 char *dirname;
866
867 for (slash = strchr(refname, '/'); slash; slash = strchr(slash + 1, '/')) {
868 /*
869 * We are still at a leading dir of the refname; we are
870 * looking for a conflict with a leaf entry.
871 *
872 * If we find one, we still must make sure it is
873 * not in "skip".
874 */
875 pos = search_ref_dir(dir, refname, slash - refname);
876 if (pos >= 0) {
877 struct ref_entry *entry = dir->entries[pos];
878 if (entry_matches(entry, skip))
879 return 1;
880 report_refname_conflict(entry, refname);
881 return 0;
882 }
883
884
885 /*
886 * Otherwise, we can try to continue our search with
887 * the next component; if we come up empty, we know
888 * there is nothing under this whole prefix.
889 */
890 pos = search_ref_dir(dir, refname, slash + 1 - refname);
891 if (pos < 0)
892 return 1;
893
894 dir = get_ref_dir(dir->entries[pos]);
895 }
896
897 /*
898 * We are at the leaf of our refname; we want to
899 * make sure there are no directories which match it.
900 */
901 len = strlen(refname);
902 dirname = xmallocz(len + 1);
903 sprintf(dirname, "%s/", refname);
904 pos = search_ref_dir(dir, dirname, len + 1);
905 free(dirname);
906
907 if (pos >= 0) {
908 /*
909 * We found a directory named "refname". It is a
910 * problem iff it contains any ref that is not
911 * in "skip".
912 */
913 struct ref_entry *entry = dir->entries[pos];
914 struct ref_dir *dir = get_ref_dir(entry);
915 struct nonmatching_ref_data data;
916
917 data.skip = skip;
918 sort_ref_dir(dir);
919 if (!do_for_each_entry_in_dir(dir, 0, nonmatching_ref_fn, &data))
920 return 1;
921
922 report_refname_conflict(data.found, refname);
923 return 0;
924 }
925
926 /*
927 * There is no point in searching for another leaf
928 * node which matches it; such an entry would be the
929 * ref we are looking for, not a conflict.
930 */
931 return 1;
932 }
933
934 struct packed_ref_cache {
935 struct ref_entry *root;
936
937 /*
938 * Count of references to the data structure in this instance,
939 * including the pointer from ref_cache::packed if any. The
940 * data will not be freed as long as the reference count is
941 * nonzero.
942 */
943 unsigned int referrers;
944
945 /*
946 * Iff the packed-refs file associated with this instance is
947 * currently locked for writing, this points at the associated
948 * lock (which is owned by somebody else). The referrer count
949 * is also incremented when the file is locked and decremented
950 * when it is unlocked.
951 */
952 struct lock_file *lock;
953
954 /* The metadata from when this packed-refs cache was read */
955 struct stat_validity validity;
956 };
957
958 /*
959 * Future: need to be in "struct repository"
960 * when doing a full libification.
961 */
962 static struct ref_cache {
963 struct ref_cache *next;
964 struct ref_entry *loose;
965 struct packed_ref_cache *packed;
966 /*
967 * The submodule name, or "" for the main repo. We allocate
968 * length 1 rather than FLEX_ARRAY so that the main ref_cache
969 * is initialized correctly.
970 */
971 char name[1];
972 } ref_cache, *submodule_ref_caches;
973
974 /* Lock used for the main packed-refs file: */
975 static struct lock_file packlock;
976
977 /*
978 * Increment the reference count of *packed_refs.
979 */
980 static void acquire_packed_ref_cache(struct packed_ref_cache *packed_refs)
981 {
982 packed_refs->referrers++;
983 }
984
985 /*
986 * Decrease the reference count of *packed_refs. If it goes to zero,
987 * free *packed_refs and return true; otherwise return false.
988 */
989 static int release_packed_ref_cache(struct packed_ref_cache *packed_refs)
990 {
991 if (!--packed_refs->referrers) {
992 free_ref_entry(packed_refs->root);
993 stat_validity_clear(&packed_refs->validity);
994 free(packed_refs);
995 return 1;
996 } else {
997 return 0;
998 }
999 }
1000
1001 static void clear_packed_ref_cache(struct ref_cache *refs)
1002 {
1003 if (refs->packed) {
1004 struct packed_ref_cache *packed_refs = refs->packed;
1005
1006 if (packed_refs->lock)
1007 die("internal error: packed-ref cache cleared while locked");
1008 refs->packed = NULL;
1009 release_packed_ref_cache(packed_refs);
1010 }
1011 }
1012
1013 static void clear_loose_ref_cache(struct ref_cache *refs)
1014 {
1015 if (refs->loose) {
1016 free_ref_entry(refs->loose);
1017 refs->loose = NULL;
1018 }
1019 }
1020
1021 static struct ref_cache *create_ref_cache(const char *submodule)
1022 {
1023 int len;
1024 struct ref_cache *refs;
1025 if (!submodule)
1026 submodule = "";
1027 len = strlen(submodule) + 1;
1028 refs = xcalloc(1, sizeof(struct ref_cache) + len);
1029 memcpy(refs->name, submodule, len);
1030 return refs;
1031 }
1032
1033 /*
1034 * Return a pointer to a ref_cache for the specified submodule. For
1035 * the main repository, use submodule==NULL. The returned structure
1036 * will be allocated and initialized but not necessarily populated; it
1037 * should not be freed.
1038 */
1039 static struct ref_cache *get_ref_cache(const char *submodule)
1040 {
1041 struct ref_cache *refs;
1042
1043 if (!submodule || !*submodule)
1044 return &ref_cache;
1045
1046 for (refs = submodule_ref_caches; refs; refs = refs->next)
1047 if (!strcmp(submodule, refs->name))
1048 return refs;
1049
1050 refs = create_ref_cache(submodule);
1051 refs->next = submodule_ref_caches;
1052 submodule_ref_caches = refs;
1053 return refs;
1054 }
1055
1056 /* The length of a peeled reference line in packed-refs, including EOL: */
1057 #define PEELED_LINE_LENGTH 42
1058
1059 /*
1060 * The packed-refs header line that we write out. Perhaps other
1061 * traits will be added later. The trailing space is required.
1062 */
1063 static const char PACKED_REFS_HEADER[] =
1064 "# pack-refs with: peeled fully-peeled \n";
1065
1066 /*
1067 * Parse one line from a packed-refs file. Write the SHA1 to sha1.
1068 * Return a pointer to the refname within the line (null-terminated),
1069 * or NULL if there was a problem.
1070 */
1071 static const char *parse_ref_line(struct strbuf *line, unsigned char *sha1)
1072 {
1073 const char *ref;
1074
1075 /*
1076 * 42: the answer to everything.
1077 *
1078 * In this case, it happens to be the answer to
1079 * 40 (length of sha1 hex representation)
1080 * +1 (space in between hex and name)
1081 * +1 (newline at the end of the line)
1082 */
1083 if (line->len <= 42)
1084 return NULL;
1085
1086 if (get_sha1_hex(line->buf, sha1) < 0)
1087 return NULL;
1088 if (!isspace(line->buf[40]))
1089 return NULL;
1090
1091 ref = line->buf + 41;
1092 if (isspace(*ref))
1093 return NULL;
1094
1095 if (line->buf[line->len - 1] != '\n')
1096 return NULL;
1097 line->buf[--line->len] = 0;
1098
1099 return ref;
1100 }
1101
1102 /*
1103 * Read f, which is a packed-refs file, into dir.
1104 *
1105 * A comment line of the form "# pack-refs with: " may contain zero or
1106 * more traits. We interpret the traits as follows:
1107 *
1108 * No traits:
1109 *
1110 * Probably no references are peeled. But if the file contains a
1111 * peeled value for a reference, we will use it.
1112 *
1113 * peeled:
1114 *
1115 * References under "refs/tags/", if they *can* be peeled, *are*
1116 * peeled in this file. References outside of "refs/tags/" are
1117 * probably not peeled even if they could have been, but if we find
1118 * a peeled value for such a reference we will use it.
1119 *
1120 * fully-peeled:
1121 *
1122 * All references in the file that can be peeled are peeled.
1123 * Inversely (and this is more important), any references in the
1124 * file for which no peeled value is recorded is not peelable. This
1125 * trait should typically be written alongside "peeled" for
1126 * compatibility with older clients, but we do not require it
1127 * (i.e., "peeled" is a no-op if "fully-peeled" is set).
1128 */
1129 static void read_packed_refs(FILE *f, struct ref_dir *dir)
1130 {
1131 struct ref_entry *last = NULL;
1132 struct strbuf line = STRBUF_INIT;
1133 enum { PEELED_NONE, PEELED_TAGS, PEELED_FULLY } peeled = PEELED_NONE;
1134
1135 while (strbuf_getwholeline(&line, f, '\n') != EOF) {
1136 unsigned char sha1[20];
1137 const char *refname;
1138 const char *traits;
1139
1140 if (skip_prefix(line.buf, "# pack-refs with:", &traits)) {
1141 if (strstr(traits, " fully-peeled "))
1142 peeled = PEELED_FULLY;
1143 else if (strstr(traits, " peeled "))
1144 peeled = PEELED_TAGS;
1145 /* perhaps other traits later as well */
1146 continue;
1147 }
1148
1149 refname = parse_ref_line(&line, sha1);
1150 if (refname) {
1151 int flag = REF_ISPACKED;
1152
1153 if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
1154 hashclr(sha1);
1155 flag |= REF_BAD_NAME | REF_ISBROKEN;
1156 }
1157 last = create_ref_entry(refname, sha1, flag, 0);
1158 if (peeled == PEELED_FULLY ||
1159 (peeled == PEELED_TAGS && starts_with(refname, "refs/tags/")))
1160 last->flag |= REF_KNOWS_PEELED;
1161 add_ref(dir, last);
1162 continue;
1163 }
1164 if (last &&
1165 line.buf[0] == '^' &&
1166 line.len == PEELED_LINE_LENGTH &&
1167 line.buf[PEELED_LINE_LENGTH - 1] == '\n' &&
1168 !get_sha1_hex(line.buf + 1, sha1)) {
1169 hashcpy(last->u.value.peeled, sha1);
1170 /*
1171 * Regardless of what the file header said,
1172 * we definitely know the value of *this*
1173 * reference:
1174 */
1175 last->flag |= REF_KNOWS_PEELED;
1176 }
1177 }
1178
1179 strbuf_release(&line);
1180 }
1181
1182 /*
1183 * Get the packed_ref_cache for the specified ref_cache, creating it
1184 * if necessary.
1185 */
1186 static struct packed_ref_cache *get_packed_ref_cache(struct ref_cache *refs)
1187 {
1188 const char *packed_refs_file;
1189
1190 if (*refs->name)
1191 packed_refs_file = git_path_submodule(refs->name, "packed-refs");
1192 else
1193 packed_refs_file = git_path("packed-refs");
1194
1195 if (refs->packed &&
1196 !stat_validity_check(&refs->packed->validity, packed_refs_file))
1197 clear_packed_ref_cache(refs);
1198
1199 if (!refs->packed) {
1200 FILE *f;
1201
1202 refs->packed = xcalloc(1, sizeof(*refs->packed));
1203 acquire_packed_ref_cache(refs->packed);
1204 refs->packed->root = create_dir_entry(refs, "", 0, 0);
1205 f = fopen(packed_refs_file, "r");
1206 if (f) {
1207 stat_validity_update(&refs->packed->validity, fileno(f));
1208 read_packed_refs(f, get_ref_dir(refs->packed->root));
1209 fclose(f);
1210 }
1211 }
1212 return refs->packed;
1213 }
1214
1215 static struct ref_dir *get_packed_ref_dir(struct packed_ref_cache *packed_ref_cache)
1216 {
1217 return get_ref_dir(packed_ref_cache->root);
1218 }
1219
1220 static struct ref_dir *get_packed_refs(struct ref_cache *refs)
1221 {
1222 return get_packed_ref_dir(get_packed_ref_cache(refs));
1223 }
1224
1225 void add_packed_ref(const char *refname, const unsigned char *sha1)
1226 {
1227 struct packed_ref_cache *packed_ref_cache =
1228 get_packed_ref_cache(&ref_cache);
1229
1230 if (!packed_ref_cache->lock)
1231 die("internal error: packed refs not locked");
1232 add_ref(get_packed_ref_dir(packed_ref_cache),
1233 create_ref_entry(refname, sha1, REF_ISPACKED, 1));
1234 }
1235
1236 /*
1237 * Read the loose references from the namespace dirname into dir
1238 * (without recursing). dirname must end with '/'. dir must be the
1239 * directory entry corresponding to dirname.
1240 */
1241 static void read_loose_refs(const char *dirname, struct ref_dir *dir)
1242 {
1243 struct ref_cache *refs = dir->ref_cache;
1244 DIR *d;
1245 const char *path;
1246 struct dirent *de;
1247 int dirnamelen = strlen(dirname);
1248 struct strbuf refname;
1249
1250 if (*refs->name)
1251 path = git_path_submodule(refs->name, "%s", dirname);
1252 else
1253 path = git_path("%s", dirname);
1254
1255 d = opendir(path);
1256 if (!d)
1257 return;
1258
1259 strbuf_init(&refname, dirnamelen + 257);
1260 strbuf_add(&refname, dirname, dirnamelen);
1261
1262 while ((de = readdir(d)) != NULL) {
1263 unsigned char sha1[20];
1264 struct stat st;
1265 int flag;
1266 const char *refdir;
1267
1268 if (de->d_name[0] == '.')
1269 continue;
1270 if (ends_with(de->d_name, ".lock"))
1271 continue;
1272 strbuf_addstr(&refname, de->d_name);
1273 refdir = *refs->name
1274 ? git_path_submodule(refs->name, "%s", refname.buf)
1275 : git_path("%s", refname.buf);
1276 if (stat(refdir, &st) < 0) {
1277 ; /* silently ignore */
1278 } else if (S_ISDIR(st.st_mode)) {
1279 strbuf_addch(&refname, '/');
1280 add_entry_to_dir(dir,
1281 create_dir_entry(refs, refname.buf,
1282 refname.len, 1));
1283 } else {
1284 if (*refs->name) {
1285 hashclr(sha1);
1286 flag = 0;
1287 if (resolve_gitlink_ref(refs->name, refname.buf, sha1) < 0) {
1288 hashclr(sha1);
1289 flag |= REF_ISBROKEN;
1290 }
1291 } else if (read_ref_full(refname.buf,
1292 RESOLVE_REF_READING,
1293 sha1, &flag)) {
1294 hashclr(sha1);
1295 flag |= REF_ISBROKEN;
1296 }
1297 if (check_refname_format(refname.buf,
1298 REFNAME_ALLOW_ONELEVEL)) {
1299 hashclr(sha1);
1300 flag |= REF_BAD_NAME | REF_ISBROKEN;
1301 }
1302 add_entry_to_dir(dir,
1303 create_ref_entry(refname.buf, sha1, flag, 0));
1304 }
1305 strbuf_setlen(&refname, dirnamelen);
1306 }
1307 strbuf_release(&refname);
1308 closedir(d);
1309 }
1310
1311 static struct ref_dir *get_loose_refs(struct ref_cache *refs)
1312 {
1313 if (!refs->loose) {
1314 /*
1315 * Mark the top-level directory complete because we
1316 * are about to read the only subdirectory that can
1317 * hold references:
1318 */
1319 refs->loose = create_dir_entry(refs, "", 0, 0);
1320 /*
1321 * Create an incomplete entry for "refs/":
1322 */
1323 add_entry_to_dir(get_ref_dir(refs->loose),
1324 create_dir_entry(refs, "refs/", 5, 1));
1325 }
1326 return get_ref_dir(refs->loose);
1327 }
1328
1329 /* We allow "recursive" symbolic refs. Only within reason, though */
1330 #define MAXDEPTH 5
1331 #define MAXREFLEN (1024)
1332
1333 /*
1334 * Called by resolve_gitlink_ref_recursive() after it failed to read
1335 * from the loose refs in ref_cache refs. Find <refname> in the
1336 * packed-refs file for the submodule.
1337 */
1338 static int resolve_gitlink_packed_ref(struct ref_cache *refs,
1339 const char *refname, unsigned char *sha1)
1340 {
1341 struct ref_entry *ref;
1342 struct ref_dir *dir = get_packed_refs(refs);
1343
1344 ref = find_ref(dir, refname);
1345 if (ref == NULL)
1346 return -1;
1347
1348 hashcpy(sha1, ref->u.value.sha1);
1349 return 0;
1350 }
1351
1352 static int resolve_gitlink_ref_recursive(struct ref_cache *refs,
1353 const char *refname, unsigned char *sha1,
1354 int recursion)
1355 {
1356 int fd, len;
1357 char buffer[128], *p;
1358 char *path;
1359
1360 if (recursion > MAXDEPTH || strlen(refname) > MAXREFLEN)
1361 return -1;
1362 path = *refs->name
1363 ? git_path_submodule(refs->name, "%s", refname)
1364 : git_path("%s", refname);
1365 fd = open(path, O_RDONLY);
1366 if (fd < 0)
1367 return resolve_gitlink_packed_ref(refs, refname, sha1);
1368
1369 len = read(fd, buffer, sizeof(buffer)-1);
1370 close(fd);
1371 if (len < 0)
1372 return -1;
1373 while (len && isspace(buffer[len-1]))
1374 len--;
1375 buffer[len] = 0;
1376
1377 /* Was it a detached head or an old-fashioned symlink? */
1378 if (!get_sha1_hex(buffer, sha1))
1379 return 0;
1380
1381 /* Symref? */
1382 if (strncmp(buffer, "ref:", 4))
1383 return -1;
1384 p = buffer + 4;
1385 while (isspace(*p))
1386 p++;
1387
1388 return resolve_gitlink_ref_recursive(refs, p, sha1, recursion+1);
1389 }
1390
1391 int resolve_gitlink_ref(const char *path, const char *refname, unsigned char *sha1)
1392 {
1393 int len = strlen(path), retval;
1394 char *submodule;
1395 struct ref_cache *refs;
1396
1397 while (len && path[len-1] == '/')
1398 len--;
1399 if (!len)
1400 return -1;
1401 submodule = xstrndup(path, len);
1402 refs = get_ref_cache(submodule);
1403 free(submodule);
1404
1405 retval = resolve_gitlink_ref_recursive(refs, refname, sha1, 0);
1406 return retval;
1407 }
1408
1409 /*
1410 * Return the ref_entry for the given refname from the packed
1411 * references. If it does not exist, return NULL.
1412 */
1413 static struct ref_entry *get_packed_ref(const char *refname)
1414 {
1415 return find_ref(get_packed_refs(&ref_cache), refname);
1416 }
1417
1418 /*
1419 * A loose ref file doesn't exist; check for a packed ref. The
1420 * options are forwarded from resolve_safe_unsafe().
1421 */
1422 static int resolve_missing_loose_ref(const char *refname,
1423 int resolve_flags,
1424 unsigned char *sha1,
1425 int *flags)
1426 {
1427 struct ref_entry *entry;
1428
1429 /*
1430 * The loose reference file does not exist; check for a packed
1431 * reference.
1432 */
1433 entry = get_packed_ref(refname);
1434 if (entry) {
1435 hashcpy(sha1, entry->u.value.sha1);
1436 if (flags)
1437 *flags |= REF_ISPACKED;
1438 return 0;
1439 }
1440 /* The reference is not a packed reference, either. */
1441 if (resolve_flags & RESOLVE_REF_READING) {
1442 errno = ENOENT;
1443 return -1;
1444 } else {
1445 hashclr(sha1);
1446 return 0;
1447 }
1448 }
1449
1450 /* This function needs to return a meaningful errno on failure */
1451 const char *resolve_ref_unsafe(const char *refname, int resolve_flags, unsigned char *sha1, int *flags)
1452 {
1453 int depth = MAXDEPTH;
1454 ssize_t len;
1455 char buffer[256];
1456 static char refname_buffer[256];
1457 int bad_name = 0;
1458
1459 if (flags)
1460 *flags = 0;
1461
1462 if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
1463 if (flags)
1464 *flags |= REF_BAD_NAME;
1465
1466 if (!(resolve_flags & RESOLVE_REF_ALLOW_BAD_NAME) ||
1467 !refname_is_safe(refname)) {
1468 errno = EINVAL;
1469 return NULL;
1470 }
1471 /*
1472 * dwim_ref() uses REF_ISBROKEN to distinguish between
1473 * missing refs and refs that were present but invalid,
1474 * to complain about the latter to stderr.
1475 *
1476 * We don't know whether the ref exists, so don't set
1477 * REF_ISBROKEN yet.
1478 */
1479 bad_name = 1;
1480 }
1481 for (;;) {
1482 char path[PATH_MAX];
1483 struct stat st;
1484 char *buf;
1485 int fd;
1486
1487 if (--depth < 0) {
1488 errno = ELOOP;
1489 return NULL;
1490 }
1491
1492 git_snpath(path, sizeof(path), "%s", refname);
1493
1494 /*
1495 * We might have to loop back here to avoid a race
1496 * condition: first we lstat() the file, then we try
1497 * to read it as a link or as a file. But if somebody
1498 * changes the type of the file (file <-> directory
1499 * <-> symlink) between the lstat() and reading, then
1500 * we don't want to report that as an error but rather
1501 * try again starting with the lstat().
1502 */
1503 stat_ref:
1504 if (lstat(path, &st) < 0) {
1505 if (errno != ENOENT)
1506 return NULL;
1507 if (resolve_missing_loose_ref(refname, resolve_flags,
1508 sha1, flags))
1509 return NULL;
1510 if (bad_name) {
1511 hashclr(sha1);
1512 if (flags)
1513 *flags |= REF_ISBROKEN;
1514 }
1515 return refname;
1516 }
1517
1518 /* Follow "normalized" - ie "refs/.." symlinks by hand */
1519 if (S_ISLNK(st.st_mode)) {
1520 len = readlink(path, buffer, sizeof(buffer)-1);
1521 if (len < 0) {
1522 if (errno == ENOENT || errno == EINVAL)
1523 /* inconsistent with lstat; retry */
1524 goto stat_ref;
1525 else
1526 return NULL;
1527 }
1528 buffer[len] = 0;
1529 if (starts_with(buffer, "refs/") &&
1530 !check_refname_format(buffer, 0)) {
1531 strcpy(refname_buffer, buffer);
1532 refname = refname_buffer;
1533 if (flags)
1534 *flags |= REF_ISSYMREF;
1535 if (resolve_flags & RESOLVE_REF_NO_RECURSE) {
1536 hashclr(sha1);
1537 return refname;
1538 }
1539 continue;
1540 }
1541 }
1542
1543 /* Is it a directory? */
1544 if (S_ISDIR(st.st_mode)) {
1545 errno = EISDIR;
1546 return NULL;
1547 }
1548
1549 /*
1550 * Anything else, just open it and try to use it as
1551 * a ref
1552 */
1553 fd = open(path, O_RDONLY);
1554 if (fd < 0) {
1555 if (errno == ENOENT)
1556 /* inconsistent with lstat; retry */
1557 goto stat_ref;
1558 else
1559 return NULL;
1560 }
1561 len = read_in_full(fd, buffer, sizeof(buffer)-1);
1562 if (len < 0) {
1563 int save_errno = errno;
1564 close(fd);
1565 errno = save_errno;
1566 return NULL;
1567 }
1568 close(fd);
1569 while (len && isspace(buffer[len-1]))
1570 len--;
1571 buffer[len] = '\0';
1572
1573 /*
1574 * Is it a symbolic ref?
1575 */
1576 if (!starts_with(buffer, "ref:")) {
1577 /*
1578 * Please note that FETCH_HEAD has a second
1579 * line containing other data.
1580 */
1581 if (get_sha1_hex(buffer, sha1) ||
1582 (buffer[40] != '\0' && !isspace(buffer[40]))) {
1583 if (flags)
1584 *flags |= REF_ISBROKEN;
1585 errno = EINVAL;
1586 return NULL;
1587 }
1588 if (bad_name) {
1589 hashclr(sha1);
1590 if (flags)
1591 *flags |= REF_ISBROKEN;
1592 }
1593 return refname;
1594 }
1595 if (flags)
1596 *flags |= REF_ISSYMREF;
1597 buf = buffer + 4;
1598 while (isspace(*buf))
1599 buf++;
1600 refname = strcpy(refname_buffer, buf);
1601 if (resolve_flags & RESOLVE_REF_NO_RECURSE) {
1602 hashclr(sha1);
1603 return refname;
1604 }
1605 if (check_refname_format(buf, REFNAME_ALLOW_ONELEVEL)) {
1606 if (flags)
1607 *flags |= REF_ISBROKEN;
1608
1609 if (!(resolve_flags & RESOLVE_REF_ALLOW_BAD_NAME) ||
1610 !refname_is_safe(buf)) {
1611 errno = EINVAL;
1612 return NULL;
1613 }
1614 bad_name = 1;
1615 }
1616 }
1617 }
1618
1619 char *resolve_refdup(const char *ref, int resolve_flags, unsigned char *sha1, int *flags)
1620 {
1621 return xstrdup_or_null(resolve_ref_unsafe(ref, resolve_flags, sha1, flags));
1622 }
1623
1624 /* The argument to filter_refs */
1625 struct ref_filter {
1626 const char *pattern;
1627 each_ref_fn *fn;
1628 void *cb_data;
1629 };
1630
1631 int read_ref_full(const char *refname, int resolve_flags, unsigned char *sha1, int *flags)
1632 {
1633 if (resolve_ref_unsafe(refname, resolve_flags, sha1, flags))
1634 return 0;
1635 return -1;
1636 }
1637
1638 int read_ref(const char *refname, unsigned char *sha1)
1639 {
1640 return read_ref_full(refname, RESOLVE_REF_READING, sha1, NULL);
1641 }
1642
1643 int ref_exists(const char *refname)
1644 {
1645 unsigned char sha1[20];
1646 return !!resolve_ref_unsafe(refname, RESOLVE_REF_READING, sha1, NULL);
1647 }
1648
1649 static int filter_refs(const char *refname, const unsigned char *sha1, int flags,
1650 void *data)
1651 {
1652 struct ref_filter *filter = (struct ref_filter *)data;
1653 if (wildmatch(filter->pattern, refname, 0, NULL))
1654 return 0;
1655 return filter->fn(refname, sha1, flags, filter->cb_data);
1656 }
1657
1658 enum peel_status {
1659 /* object was peeled successfully: */
1660 PEEL_PEELED = 0,
1661
1662 /*
1663 * object cannot be peeled because the named object (or an
1664 * object referred to by a tag in the peel chain), does not
1665 * exist.
1666 */
1667 PEEL_INVALID = -1,
1668
1669 /* object cannot be peeled because it is not a tag: */
1670 PEEL_NON_TAG = -2,
1671
1672 /* ref_entry contains no peeled value because it is a symref: */
1673 PEEL_IS_SYMREF = -3,
1674
1675 /*
1676 * ref_entry cannot be peeled because it is broken (i.e., the
1677 * symbolic reference cannot even be resolved to an object
1678 * name):
1679 */
1680 PEEL_BROKEN = -4
1681 };
1682
1683 /*
1684 * Peel the named object; i.e., if the object is a tag, resolve the
1685 * tag recursively until a non-tag is found. If successful, store the
1686 * result to sha1 and return PEEL_PEELED. If the object is not a tag
1687 * or is not valid, return PEEL_NON_TAG or PEEL_INVALID, respectively,
1688 * and leave sha1 unchanged.
1689 */
1690 static enum peel_status peel_object(const unsigned char *name, unsigned char *sha1)
1691 {
1692 struct object *o = lookup_unknown_object(name);
1693
1694 if (o->type == OBJ_NONE) {
1695 int type = sha1_object_info(name, NULL);
1696 if (type < 0 || !object_as_type(o, type, 0))
1697 return PEEL_INVALID;
1698 }
1699
1700 if (o->type != OBJ_TAG)
1701 return PEEL_NON_TAG;
1702
1703 o = deref_tag_noverify(o);
1704 if (!o)
1705 return PEEL_INVALID;
1706
1707 hashcpy(sha1, o->sha1);
1708 return PEEL_PEELED;
1709 }
1710
1711 /*
1712 * Peel the entry (if possible) and return its new peel_status. If
1713 * repeel is true, re-peel the entry even if there is an old peeled
1714 * value that is already stored in it.
1715 *
1716 * It is OK to call this function with a packed reference entry that
1717 * might be stale and might even refer to an object that has since
1718 * been garbage-collected. In such a case, if the entry has
1719 * REF_KNOWS_PEELED then leave the status unchanged and return
1720 * PEEL_PEELED or PEEL_NON_TAG; otherwise, return PEEL_INVALID.
1721 */
1722 static enum peel_status peel_entry(struct ref_entry *entry, int repeel)
1723 {
1724 enum peel_status status;
1725
1726 if (entry->flag & REF_KNOWS_PEELED) {
1727 if (repeel) {
1728 entry->flag &= ~REF_KNOWS_PEELED;
1729 hashclr(entry->u.value.peeled);
1730 } else {
1731 return is_null_sha1(entry->u.value.peeled) ?
1732 PEEL_NON_TAG : PEEL_PEELED;
1733 }
1734 }
1735 if (entry->flag & REF_ISBROKEN)
1736 return PEEL_BROKEN;
1737 if (entry->flag & REF_ISSYMREF)
1738 return PEEL_IS_SYMREF;
1739
1740 status = peel_object(entry->u.value.sha1, entry->u.value.peeled);
1741 if (status == PEEL_PEELED || status == PEEL_NON_TAG)
1742 entry->flag |= REF_KNOWS_PEELED;
1743 return status;
1744 }
1745
1746 int peel_ref(const char *refname, unsigned char *sha1)
1747 {
1748 int flag;
1749 unsigned char base[20];
1750
1751 if (current_ref && (current_ref->name == refname
1752 || !strcmp(current_ref->name, refname))) {
1753 if (peel_entry(current_ref, 0))
1754 return -1;
1755 hashcpy(sha1, current_ref->u.value.peeled);
1756 return 0;
1757 }
1758
1759 if (read_ref_full(refname, RESOLVE_REF_READING, base, &flag))
1760 return -1;
1761
1762 /*
1763 * If the reference is packed, read its ref_entry from the
1764 * cache in the hope that we already know its peeled value.
1765 * We only try this optimization on packed references because
1766 * (a) forcing the filling of the loose reference cache could
1767 * be expensive and (b) loose references anyway usually do not
1768 * have REF_KNOWS_PEELED.
1769 */
1770 if (flag & REF_ISPACKED) {
1771 struct ref_entry *r = get_packed_ref(refname);
1772 if (r) {
1773 if (peel_entry(r, 0))
1774 return -1;
1775 hashcpy(sha1, r->u.value.peeled);
1776 return 0;
1777 }
1778 }
1779
1780 return peel_object(base, sha1);
1781 }
1782
1783 struct warn_if_dangling_data {
1784 FILE *fp;
1785 const char *refname;
1786 const struct string_list *refnames;
1787 const char *msg_fmt;
1788 };
1789
1790 static int warn_if_dangling_symref(const char *refname, const unsigned char *sha1,
1791 int flags, void *cb_data)
1792 {
1793 struct warn_if_dangling_data *d = cb_data;
1794 const char *resolves_to;
1795 unsigned char junk[20];
1796
1797 if (!(flags & REF_ISSYMREF))
1798 return 0;
1799
1800 resolves_to = resolve_ref_unsafe(refname, 0, junk, NULL);
1801 if (!resolves_to
1802 || (d->refname
1803 ? strcmp(resolves_to, d->refname)
1804 : !string_list_has_string(d->refnames, resolves_to))) {
1805 return 0;
1806 }
1807
1808 fprintf(d->fp, d->msg_fmt, refname);
1809 fputc('\n', d->fp);
1810 return 0;
1811 }
1812
1813 void warn_dangling_symref(FILE *fp, const char *msg_fmt, const char *refname)
1814 {
1815 struct warn_if_dangling_data data;
1816
1817 data.fp = fp;
1818 data.refname = refname;
1819 data.refnames = NULL;
1820 data.msg_fmt = msg_fmt;
1821 for_each_rawref(warn_if_dangling_symref, &data);
1822 }
1823
1824 void warn_dangling_symrefs(FILE *fp, const char *msg_fmt, const struct string_list *refnames)
1825 {
1826 struct warn_if_dangling_data data;
1827
1828 data.fp = fp;
1829 data.refname = NULL;
1830 data.refnames = refnames;
1831 data.msg_fmt = msg_fmt;
1832 for_each_rawref(warn_if_dangling_symref, &data);
1833 }
1834
1835 /*
1836 * Call fn for each reference in the specified ref_cache, omitting
1837 * references not in the containing_dir of base. fn is called for all
1838 * references, including broken ones. If fn ever returns a non-zero
1839 * value, stop the iteration and return that value; otherwise, return
1840 * 0.
1841 */
1842 static int do_for_each_entry(struct ref_cache *refs, const char *base,
1843 each_ref_entry_fn fn, void *cb_data)
1844 {
1845 struct packed_ref_cache *packed_ref_cache;
1846 struct ref_dir *loose_dir;
1847 struct ref_dir *packed_dir;
1848 int retval = 0;
1849
1850 /*
1851 * We must make sure that all loose refs are read before accessing the
1852 * packed-refs file; this avoids a race condition in which loose refs
1853 * are migrated to the packed-refs file by a simultaneous process, but
1854 * our in-memory view is from before the migration. get_packed_ref_cache()
1855 * takes care of making sure our view is up to date with what is on
1856 * disk.
1857 */
1858 loose_dir = get_loose_refs(refs);
1859 if (base && *base) {
1860 loose_dir = find_containing_dir(loose_dir, base, 0);
1861 }
1862 if (loose_dir)
1863 prime_ref_dir(loose_dir);
1864
1865 packed_ref_cache = get_packed_ref_cache(refs);
1866 acquire_packed_ref_cache(packed_ref_cache);
1867 packed_dir = get_packed_ref_dir(packed_ref_cache);
1868 if (base && *base) {
1869 packed_dir = find_containing_dir(packed_dir, base, 0);
1870 }
1871
1872 if (packed_dir && loose_dir) {
1873 sort_ref_dir(packed_dir);
1874 sort_ref_dir(loose_dir);
1875 retval = do_for_each_entry_in_dirs(
1876 packed_dir, loose_dir, fn, cb_data);
1877 } else if (packed_dir) {
1878 sort_ref_dir(packed_dir);
1879 retval = do_for_each_entry_in_dir(
1880 packed_dir, 0, fn, cb_data);
1881 } else if (loose_dir) {
1882 sort_ref_dir(loose_dir);
1883 retval = do_for_each_entry_in_dir(
1884 loose_dir, 0, fn, cb_data);
1885 }
1886
1887 release_packed_ref_cache(packed_ref_cache);
1888 return retval;
1889 }
1890
1891 /*
1892 * Call fn for each reference in the specified ref_cache for which the
1893 * refname begins with base. If trim is non-zero, then trim that many
1894 * characters off the beginning of each refname before passing the
1895 * refname to fn. flags can be DO_FOR_EACH_INCLUDE_BROKEN to include
1896 * broken references in the iteration. If fn ever returns a non-zero
1897 * value, stop the iteration and return that value; otherwise, return
1898 * 0.
1899 */
1900 static int do_for_each_ref(struct ref_cache *refs, const char *base,
1901 each_ref_fn fn, int trim, int flags, void *cb_data)
1902 {
1903 struct ref_entry_cb data;
1904 data.base = base;
1905 data.trim = trim;
1906 data.flags = flags;
1907 data.fn = fn;
1908 data.cb_data = cb_data;
1909
1910 return do_for_each_entry(refs, base, do_one_ref, &data);
1911 }
1912
1913 static int do_head_ref(const char *submodule, each_ref_fn fn, void *cb_data)
1914 {
1915 unsigned char sha1[20];
1916 int flag;
1917
1918 if (submodule) {
1919 if (resolve_gitlink_ref(submodule, "HEAD", sha1) == 0)
1920 return fn("HEAD", sha1, 0, cb_data);
1921
1922 return 0;
1923 }
1924
1925 if (!read_ref_full("HEAD", RESOLVE_REF_READING, sha1, &flag))
1926 return fn("HEAD", sha1, flag, cb_data);
1927
1928 return 0;
1929 }
1930
1931 int head_ref(each_ref_fn fn, void *cb_data)
1932 {
1933 return do_head_ref(NULL, fn, cb_data);
1934 }
1935
1936 int head_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
1937 {
1938 return do_head_ref(submodule, fn, cb_data);
1939 }
1940
1941 int for_each_ref(each_ref_fn fn, void *cb_data)
1942 {
1943 return do_for_each_ref(&ref_cache, "", fn, 0, 0, cb_data);
1944 }
1945
1946 int for_each_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
1947 {
1948 return do_for_each_ref(get_ref_cache(submodule), "", fn, 0, 0, cb_data);
1949 }
1950
1951 int for_each_ref_in(const char *prefix, each_ref_fn fn, void *cb_data)
1952 {
1953 return do_for_each_ref(&ref_cache, prefix, fn, strlen(prefix), 0, cb_data);
1954 }
1955
1956 int for_each_ref_in_submodule(const char *submodule, const char *prefix,
1957 each_ref_fn fn, void *cb_data)
1958 {
1959 return do_for_each_ref(get_ref_cache(submodule), prefix, fn, strlen(prefix), 0, cb_data);
1960 }
1961
1962 int for_each_tag_ref(each_ref_fn fn, void *cb_data)
1963 {
1964 return for_each_ref_in("refs/tags/", fn, cb_data);
1965 }
1966
1967 int for_each_tag_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
1968 {
1969 return for_each_ref_in_submodule(submodule, "refs/tags/", fn, cb_data);
1970 }
1971
1972 int for_each_branch_ref(each_ref_fn fn, void *cb_data)
1973 {
1974 return for_each_ref_in("refs/heads/", fn, cb_data);
1975 }
1976
1977 int for_each_branch_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
1978 {
1979 return for_each_ref_in_submodule(submodule, "refs/heads/", fn, cb_data);
1980 }
1981
1982 int for_each_remote_ref(each_ref_fn fn, void *cb_data)
1983 {
1984 return for_each_ref_in("refs/remotes/", fn, cb_data);
1985 }
1986
1987 int for_each_remote_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
1988 {
1989 return for_each_ref_in_submodule(submodule, "refs/remotes/", fn, cb_data);
1990 }
1991
1992 int for_each_replace_ref(each_ref_fn fn, void *cb_data)
1993 {
1994 return do_for_each_ref(&ref_cache, "refs/replace/", fn, 13, 0, cb_data);
1995 }
1996
1997 int head_ref_namespaced(each_ref_fn fn, void *cb_data)
1998 {
1999 struct strbuf buf = STRBUF_INIT;
2000 int ret = 0;
2001 unsigned char sha1[20];
2002 int flag;
2003
2004 strbuf_addf(&buf, "%sHEAD", get_git_namespace());
2005 if (!read_ref_full(buf.buf, RESOLVE_REF_READING, sha1, &flag))
2006 ret = fn(buf.buf, sha1, flag, cb_data);
2007 strbuf_release(&buf);
2008
2009 return ret;
2010 }
2011
2012 int for_each_namespaced_ref(each_ref_fn fn, void *cb_data)
2013 {
2014 struct strbuf buf = STRBUF_INIT;
2015 int ret;
2016 strbuf_addf(&buf, "%srefs/", get_git_namespace());
2017 ret = do_for_each_ref(&ref_cache, buf.buf, fn, 0, 0, cb_data);
2018 strbuf_release(&buf);
2019 return ret;
2020 }
2021
2022 int for_each_glob_ref_in(each_ref_fn fn, const char *pattern,
2023 const char *prefix, void *cb_data)
2024 {
2025 struct strbuf real_pattern = STRBUF_INIT;
2026 struct ref_filter filter;
2027 int ret;
2028
2029 if (!prefix && !starts_with(pattern, "refs/"))
2030 strbuf_addstr(&real_pattern, "refs/");
2031 else if (prefix)
2032 strbuf_addstr(&real_pattern, prefix);
2033 strbuf_addstr(&real_pattern, pattern);
2034
2035 if (!has_glob_specials(pattern)) {
2036 /* Append implied '/' '*' if not present. */
2037 if (real_pattern.buf[real_pattern.len - 1] != '/')
2038 strbuf_addch(&real_pattern, '/');
2039 /* No need to check for '*', there is none. */
2040 strbuf_addch(&real_pattern, '*');
2041 }
2042
2043 filter.pattern = real_pattern.buf;
2044 filter.fn = fn;
2045 filter.cb_data = cb_data;
2046 ret = for_each_ref(filter_refs, &filter);
2047
2048 strbuf_release(&real_pattern);
2049 return ret;
2050 }
2051
2052 int for_each_glob_ref(each_ref_fn fn, const char *pattern, void *cb_data)
2053 {
2054 return for_each_glob_ref_in(fn, pattern, NULL, cb_data);
2055 }
2056
2057 int for_each_rawref(each_ref_fn fn, void *cb_data)
2058 {
2059 return do_for_each_ref(&ref_cache, "", fn, 0,
2060 DO_FOR_EACH_INCLUDE_BROKEN, cb_data);
2061 }
2062
2063 const char *prettify_refname(const char *name)
2064 {
2065 return name + (
2066 starts_with(name, "refs/heads/") ? 11 :
2067 starts_with(name, "refs/tags/") ? 10 :
2068 starts_with(name, "refs/remotes/") ? 13 :
2069 0);
2070 }
2071
2072 static const char *ref_rev_parse_rules[] = {
2073 "%.*s",
2074 "refs/%.*s",
2075 "refs/tags/%.*s",
2076 "refs/heads/%.*s",
2077 "refs/remotes/%.*s",
2078 "refs/remotes/%.*s/HEAD",
2079 NULL
2080 };
2081
2082 int refname_match(const char *abbrev_name, const char *full_name)
2083 {
2084 const char **p;
2085 const int abbrev_name_len = strlen(abbrev_name);
2086
2087 for (p = ref_rev_parse_rules; *p; p++) {
2088 if (!strcmp(full_name, mkpath(*p, abbrev_name_len, abbrev_name))) {
2089 return 1;
2090 }
2091 }
2092
2093 return 0;
2094 }
2095
2096 /* This function should make sure errno is meaningful on error */
2097 static struct ref_lock *verify_lock(struct ref_lock *lock,
2098 const unsigned char *old_sha1, int mustexist)
2099 {
2100 if (read_ref_full(lock->ref_name,
2101 mustexist ? RESOLVE_REF_READING : 0,
2102 lock->old_sha1, NULL)) {
2103 int save_errno = errno;
2104 error("Can't verify ref %s", lock->ref_name);
2105 unlock_ref(lock);
2106 errno = save_errno;
2107 return NULL;
2108 }
2109 if (hashcmp(lock->old_sha1, old_sha1)) {
2110 error("Ref %s is at %s but expected %s", lock->ref_name,
2111 sha1_to_hex(lock->old_sha1), sha1_to_hex(old_sha1));
2112 unlock_ref(lock);
2113 errno = EBUSY;
2114 return NULL;
2115 }
2116 return lock;
2117 }
2118
2119 static int remove_empty_directories(const char *file)
2120 {
2121 /* we want to create a file but there is a directory there;
2122 * if that is an empty directory (or a directory that contains
2123 * only empty directories), remove them.
2124 */
2125 struct strbuf path;
2126 int result, save_errno;
2127
2128 strbuf_init(&path, 20);
2129 strbuf_addstr(&path, file);
2130
2131 result = remove_dir_recursively(&path, REMOVE_DIR_EMPTY_ONLY);
2132 save_errno = errno;
2133
2134 strbuf_release(&path);
2135 errno = save_errno;
2136
2137 return result;
2138 }
2139
2140 /*
2141 * *string and *len will only be substituted, and *string returned (for
2142 * later free()ing) if the string passed in is a magic short-hand form
2143 * to name a branch.
2144 */
2145 static char *substitute_branch_name(const char **string, int *len)
2146 {
2147 struct strbuf buf = STRBUF_INIT;
2148 int ret = interpret_branch_name(*string, *len, &buf);
2149
2150 if (ret == *len) {
2151 size_t size;
2152 *string = strbuf_detach(&buf, &size);
2153 *len = size;
2154 return (char *)*string;
2155 }
2156
2157 return NULL;
2158 }
2159
2160 int dwim_ref(const char *str, int len, unsigned char *sha1, char **ref)
2161 {
2162 char *last_branch = substitute_branch_name(&str, &len);
2163 const char **p, *r;
2164 int refs_found = 0;
2165
2166 *ref = NULL;
2167 for (p = ref_rev_parse_rules; *p; p++) {
2168 char fullref[PATH_MAX];
2169 unsigned char sha1_from_ref[20];
2170 unsigned char *this_result;
2171 int flag;
2172
2173 this_result = refs_found ? sha1_from_ref : sha1;
2174 mksnpath(fullref, sizeof(fullref), *p, len, str);
2175 r = resolve_ref_unsafe(fullref, RESOLVE_REF_READING,
2176 this_result, &flag);
2177 if (r) {
2178 if (!refs_found++)
2179 *ref = xstrdup(r);
2180 if (!warn_ambiguous_refs)
2181 break;
2182 } else if ((flag & REF_ISSYMREF) && strcmp(fullref, "HEAD")) {
2183 warning("ignoring dangling symref %s.", fullref);
2184 } else if ((flag & REF_ISBROKEN) && strchr(fullref, '/')) {
2185 warning("ignoring broken ref %s.", fullref);
2186 }
2187 }
2188 free(last_branch);
2189 return refs_found;
2190 }
2191
2192 int dwim_log(const char *str, int len, unsigned char *sha1, char **log)
2193 {
2194 char *last_branch = substitute_branch_name(&str, &len);
2195 const char **p;
2196 int logs_found = 0;
2197
2198 *log = NULL;
2199 for (p = ref_rev_parse_rules; *p; p++) {
2200 unsigned char hash[20];
2201 char path[PATH_MAX];
2202 const char *ref, *it;
2203
2204 mksnpath(path, sizeof(path), *p, len, str);
2205 ref = resolve_ref_unsafe(path, RESOLVE_REF_READING,
2206 hash, NULL);
2207 if (!ref)
2208 continue;
2209 if (reflog_exists(path))
2210 it = path;
2211 else if (strcmp(ref, path) && reflog_exists(ref))
2212 it = ref;
2213 else
2214 continue;
2215 if (!logs_found++) {
2216 *log = xstrdup(it);
2217 hashcpy(sha1, hash);
2218 }
2219 if (!warn_ambiguous_refs)
2220 break;
2221 }
2222 free(last_branch);
2223 return logs_found;
2224 }
2225
2226 /*
2227 * Locks a ref returning the lock on success and NULL on failure.
2228 * On failure errno is set to something meaningful.
2229 */
2230 static struct ref_lock *lock_ref_sha1_basic(const char *refname,
2231 const unsigned char *old_sha1,
2232 const struct string_list *skip,
2233 int flags, int *type_p)
2234 {
2235 char *ref_file;
2236 const char *orig_refname = refname;
2237 struct ref_lock *lock;
2238 int last_errno = 0;
2239 int type, lflags;
2240 int mustexist = (old_sha1 && !is_null_sha1(old_sha1));
2241 int resolve_flags = 0;
2242 int missing = 0;
2243 int attempts_remaining = 3;
2244
2245 lock = xcalloc(1, sizeof(struct ref_lock));
2246 lock->lock_fd = -1;
2247
2248 if (mustexist)
2249 resolve_flags |= RESOLVE_REF_READING;
2250 if (flags & REF_DELETING) {
2251 resolve_flags |= RESOLVE_REF_ALLOW_BAD_NAME;
2252 if (flags & REF_NODEREF)
2253 resolve_flags |= RESOLVE_REF_NO_RECURSE;
2254 }
2255
2256 refname = resolve_ref_unsafe(refname, resolve_flags,
2257 lock->old_sha1, &type);
2258 if (!refname && errno == EISDIR) {
2259 /* we are trying to lock foo but we used to
2260 * have foo/bar which now does not exist;
2261 * it is normal for the empty directory 'foo'
2262 * to remain.
2263 */
2264 ref_file = git_path("%s", orig_refname);
2265 if (remove_empty_directories(ref_file)) {
2266 last_errno = errno;
2267 error("there are still refs under '%s'", orig_refname);
2268 goto error_return;
2269 }
2270 refname = resolve_ref_unsafe(orig_refname, resolve_flags,
2271 lock->old_sha1, &type);
2272 }
2273 if (type_p)
2274 *type_p = type;
2275 if (!refname) {
2276 last_errno = errno;
2277 error("unable to resolve reference %s: %s",
2278 orig_refname, strerror(errno));
2279 goto error_return;
2280 }
2281 missing = is_null_sha1(lock->old_sha1);
2282 /* When the ref did not exist and we are creating it,
2283 * make sure there is no existing ref that is packed
2284 * whose name begins with our refname, nor a ref whose
2285 * name is a proper prefix of our refname.
2286 */
2287 if (missing &&
2288 !is_refname_available(refname, skip, get_packed_refs(&ref_cache))) {
2289 last_errno = ENOTDIR;
2290 goto error_return;
2291 }
2292
2293 lock->lk = xcalloc(1, sizeof(struct lock_file));
2294
2295 lflags = 0;
2296 if (flags & REF_NODEREF) {
2297 refname = orig_refname;
2298 lflags |= LOCK_NO_DEREF;
2299 }
2300 lock->ref_name = xstrdup(refname);
2301 lock->orig_ref_name = xstrdup(orig_refname);
2302 ref_file = git_path("%s", refname);
2303 if (missing)
2304 lock->force_write = 1;
2305 if ((flags & REF_NODEREF) && (type & REF_ISSYMREF))
2306 lock->force_write = 1;
2307
2308 retry:
2309 switch (safe_create_leading_directories(ref_file)) {
2310 case SCLD_OK:
2311 break; /* success */
2312 case SCLD_VANISHED:
2313 if (--attempts_remaining > 0)
2314 goto retry;
2315 /* fall through */
2316 default:
2317 last_errno = errno;
2318 error("unable to create directory for %s", ref_file);
2319 goto error_return;
2320 }
2321
2322 lock->lock_fd = hold_lock_file_for_update(lock->lk, ref_file, lflags);
2323 if (lock->lock_fd < 0) {
2324 last_errno = errno;
2325 if (errno == ENOENT && --attempts_remaining > 0)
2326 /*
2327 * Maybe somebody just deleted one of the
2328 * directories leading to ref_file. Try
2329 * again:
2330 */
2331 goto retry;
2332 else {
2333 struct strbuf err = STRBUF_INIT;
2334 unable_to_lock_message(ref_file, errno, &err);
2335 error("%s", err.buf);
2336 strbuf_release(&err);
2337 goto error_return;
2338 }
2339 }
2340 return old_sha1 ? verify_lock(lock, old_sha1, mustexist) : lock;
2341
2342 error_return:
2343 unlock_ref(lock);
2344 errno = last_errno;
2345 return NULL;
2346 }
2347
2348 struct ref_lock *lock_any_ref_for_update(const char *refname,
2349 const unsigned char *old_sha1,
2350 int flags, int *type_p)
2351 {
2352 return lock_ref_sha1_basic(refname, old_sha1, NULL, flags, type_p);
2353 }
2354
2355 /*
2356 * Write an entry to the packed-refs file for the specified refname.
2357 * If peeled is non-NULL, write it as the entry's peeled value.
2358 */
2359 static void write_packed_entry(FILE *fh, char *refname, unsigned char *sha1,
2360 unsigned char *peeled)
2361 {
2362 fprintf_or_die(fh, "%s %s\n", sha1_to_hex(sha1), refname);
2363 if (peeled)
2364 fprintf_or_die(fh, "^%s\n", sha1_to_hex(peeled));
2365 }
2366
2367 /*
2368 * An each_ref_entry_fn that writes the entry to a packed-refs file.
2369 */
2370 static int write_packed_entry_fn(struct ref_entry *entry, void *cb_data)
2371 {
2372 enum peel_status peel_status = peel_entry(entry, 0);
2373
2374 if (peel_status != PEEL_PEELED && peel_status != PEEL_NON_TAG)
2375 error("internal error: %s is not a valid packed reference!",
2376 entry->name);
2377 write_packed_entry(cb_data, entry->name, entry->u.value.sha1,
2378 peel_status == PEEL_PEELED ?
2379 entry->u.value.peeled : NULL);
2380 return 0;
2381 }
2382
2383 /* This should return a meaningful errno on failure */
2384 int lock_packed_refs(int flags)
2385 {
2386 struct packed_ref_cache *packed_ref_cache;
2387
2388 if (hold_lock_file_for_update(&packlock, git_path("packed-refs"), flags) < 0)
2389 return -1;
2390 /*
2391 * Get the current packed-refs while holding the lock. If the
2392 * packed-refs file has been modified since we last read it,
2393 * this will automatically invalidate the cache and re-read
2394 * the packed-refs file.
2395 */
2396 packed_ref_cache = get_packed_ref_cache(&ref_cache);
2397 packed_ref_cache->lock = &packlock;
2398 /* Increment the reference count to prevent it from being freed: */
2399 acquire_packed_ref_cache(packed_ref_cache);
2400 return 0;
2401 }
2402
2403 /*
2404 * Commit the packed refs changes.
2405 * On error we must make sure that errno contains a meaningful value.
2406 */
2407 int commit_packed_refs(void)
2408 {
2409 struct packed_ref_cache *packed_ref_cache =
2410 get_packed_ref_cache(&ref_cache);
2411 int error = 0;
2412 int save_errno = 0;
2413 FILE *out;
2414
2415 if (!packed_ref_cache->lock)
2416 die("internal error: packed-refs not locked");
2417
2418 out = fdopen_lock_file(packed_ref_cache->lock, "w");
2419 if (!out)
2420 die_errno("unable to fdopen packed-refs descriptor");
2421
2422 fprintf_or_die(out, "%s", PACKED_REFS_HEADER);
2423 do_for_each_entry_in_dir(get_packed_ref_dir(packed_ref_cache),
2424 0, write_packed_entry_fn, out);
2425
2426 if (commit_lock_file(packed_ref_cache->lock)) {
2427 save_errno = errno;
2428 error = -1;
2429 }
2430 packed_ref_cache->lock = NULL;
2431 release_packed_ref_cache(packed_ref_cache);
2432 errno = save_errno;
2433 return error;
2434 }
2435
2436 void rollback_packed_refs(void)
2437 {
2438 struct packed_ref_cache *packed_ref_cache =
2439 get_packed_ref_cache(&ref_cache);
2440
2441 if (!packed_ref_cache->lock)
2442 die("internal error: packed-refs not locked");
2443 rollback_lock_file(packed_ref_cache->lock);
2444 packed_ref_cache->lock = NULL;
2445 release_packed_ref_cache(packed_ref_cache);
2446 clear_packed_ref_cache(&ref_cache);
2447 }
2448
2449 struct ref_to_prune {
2450 struct ref_to_prune *next;
2451 unsigned char sha1[20];
2452 char name[FLEX_ARRAY];
2453 };
2454
2455 struct pack_refs_cb_data {
2456 unsigned int flags;
2457 struct ref_dir *packed_refs;
2458 struct ref_to_prune *ref_to_prune;
2459 };
2460
2461 /*
2462 * An each_ref_entry_fn that is run over loose references only. If
2463 * the loose reference can be packed, add an entry in the packed ref
2464 * cache. If the reference should be pruned, also add it to
2465 * ref_to_prune in the pack_refs_cb_data.
2466 */
2467 static int pack_if_possible_fn(struct ref_entry *entry, void *cb_data)
2468 {
2469 struct pack_refs_cb_data *cb = cb_data;
2470 enum peel_status peel_status;
2471 struct ref_entry *packed_entry;
2472 int is_tag_ref = starts_with(entry->name, "refs/tags/");
2473
2474 /* ALWAYS pack tags */
2475 if (!(cb->flags & PACK_REFS_ALL) && !is_tag_ref)
2476 return 0;
2477
2478 /* Do not pack symbolic or broken refs: */
2479 if ((entry->flag & REF_ISSYMREF) || !ref_resolves_to_object(entry))
2480 return 0;
2481
2482 /* Add a packed ref cache entry equivalent to the loose entry. */
2483 peel_status = peel_entry(entry, 1);
2484 if (peel_status != PEEL_PEELED && peel_status != PEEL_NON_TAG)
2485 die("internal error peeling reference %s (%s)",
2486 entry->name, sha1_to_hex(entry->u.value.sha1));
2487 packed_entry = find_ref(cb->packed_refs, entry->name);
2488 if (packed_entry) {
2489 /* Overwrite existing packed entry with info from loose entry */
2490 packed_entry->flag = REF_ISPACKED | REF_KNOWS_PEELED;
2491 hashcpy(packed_entry->u.value.sha1, entry->u.value.sha1);
2492 } else {
2493 packed_entry = create_ref_entry(entry->name, entry->u.value.sha1,
2494 REF_ISPACKED | REF_KNOWS_PEELED, 0);
2495 add_ref(cb->packed_refs, packed_entry);
2496 }
2497 hashcpy(packed_entry->u.value.peeled, entry->u.value.peeled);
2498
2499 /* Schedule the loose reference for pruning if requested. */
2500 if ((cb->flags & PACK_REFS_PRUNE)) {
2501 int namelen = strlen(entry->name) + 1;
2502 struct ref_to_prune *n = xcalloc(1, sizeof(*n) + namelen);
2503 hashcpy(n->sha1, entry->u.value.sha1);
2504 strcpy(n->name, entry->name);
2505 n->next = cb->ref_to_prune;
2506 cb->ref_to_prune = n;
2507 }
2508 return 0;
2509 }
2510
2511 /*
2512 * Remove empty parents, but spare refs/ and immediate subdirs.
2513 * Note: munges *name.
2514 */
2515 static void try_remove_empty_parents(char *name)
2516 {
2517 char *p, *q;
2518 int i;
2519 p = name;
2520 for (i = 0; i < 2; i++) { /* refs/{heads,tags,...}/ */
2521 while (*p && *p != '/')
2522 p++;
2523 /* tolerate duplicate slashes; see check_refname_format() */
2524 while (*p == '/')
2525 p++;
2526 }
2527 for (q = p; *q; q++)
2528 ;
2529 while (1) {
2530 while (q > p && *q != '/')
2531 q--;
2532 while (q > p && *(q-1) == '/')
2533 q--;
2534 if (q == p)
2535 break;
2536 *q = '\0';
2537 if (rmdir(git_path("%s", name)))
2538 break;
2539 }
2540 }
2541
2542 /* make sure nobody touched the ref, and unlink */
2543 static void prune_ref(struct ref_to_prune *r)
2544 {
2545 struct ref_transaction *transaction;
2546 struct strbuf err = STRBUF_INIT;
2547
2548 if (check_refname_format(r->name, 0))
2549 return;
2550
2551 transaction = ref_transaction_begin(&err);
2552 if (!transaction ||
2553 ref_transaction_delete(transaction, r->name, r->sha1,
2554 REF_ISPRUNING, 1, NULL, &err) ||
2555 ref_transaction_commit(transaction, &err)) {
2556 ref_transaction_free(transaction);
2557 error("%s", err.buf);
2558 strbuf_release(&err);
2559 return;
2560 }
2561 ref_transaction_free(transaction);
2562 strbuf_release(&err);
2563 try_remove_empty_parents(r->name);
2564 }
2565
2566 static void prune_refs(struct ref_to_prune *r)
2567 {
2568 while (r) {
2569 prune_ref(r);
2570 r = r->next;
2571 }
2572 }
2573
2574 int pack_refs(unsigned int flags)
2575 {
2576 struct pack_refs_cb_data cbdata;
2577
2578 memset(&cbdata, 0, sizeof(cbdata));
2579 cbdata.flags = flags;
2580
2581 lock_packed_refs(LOCK_DIE_ON_ERROR);
2582 cbdata.packed_refs = get_packed_refs(&ref_cache);
2583
2584 do_for_each_entry_in_dir(get_loose_refs(&ref_cache), 0,
2585 pack_if_possible_fn, &cbdata);
2586
2587 if (commit_packed_refs())
2588 die_errno("unable to overwrite old ref-pack file");
2589
2590 prune_refs(cbdata.ref_to_prune);
2591 return 0;
2592 }
2593
2594 /*
2595 * If entry is no longer needed in packed-refs, add it to the string
2596 * list pointed to by cb_data. Reasons for deleting entries:
2597 *
2598 * - Entry is broken.
2599 * - Entry is overridden by a loose ref.
2600 * - Entry does not point at a valid object.
2601 *
2602 * In the first and third cases, also emit an error message because these
2603 * are indications of repository corruption.
2604 */
2605 static int curate_packed_ref_fn(struct ref_entry *entry, void *cb_data)
2606 {
2607 struct string_list *refs_to_delete = cb_data;
2608
2609 if (entry->flag & REF_ISBROKEN) {
2610 /* This shouldn't happen to packed refs. */
2611 error("%s is broken!", entry->name);
2612 string_list_append(refs_to_delete, entry->name);
2613 return 0;
2614 }
2615 if (!has_sha1_file(entry->u.value.sha1)) {
2616 unsigned char sha1[20];
2617 int flags;
2618
2619 if (read_ref_full(entry->name, 0, sha1, &flags))
2620 /* We should at least have found the packed ref. */
2621 die("Internal error");
2622 if ((flags & REF_ISSYMREF) || !(flags & REF_ISPACKED)) {
2623 /*
2624 * This packed reference is overridden by a
2625 * loose reference, so it is OK that its value
2626 * is no longer valid; for example, it might
2627 * refer to an object that has been garbage
2628 * collected. For this purpose we don't even
2629 * care whether the loose reference itself is
2630 * invalid, broken, symbolic, etc. Silently
2631 * remove the packed reference.
2632 */
2633 string_list_append(refs_to_delete, entry->name);
2634 return 0;
2635 }
2636 /*
2637 * There is no overriding loose reference, so the fact
2638 * that this reference doesn't refer to a valid object
2639 * indicates some kind of repository corruption.
2640 * Report the problem, then omit the reference from
2641 * the output.
2642 */
2643 error("%s does not point to a valid object!", entry->name);
2644 string_list_append(refs_to_delete, entry->name);
2645 return 0;
2646 }
2647
2648 return 0;
2649 }
2650
2651 int repack_without_refs(struct string_list *refnames, struct strbuf *err)
2652 {
2653 struct ref_dir *packed;
2654 struct string_list refs_to_delete = STRING_LIST_INIT_DUP;
2655 struct string_list_item *refname, *ref_to_delete;
2656 int ret, needs_repacking = 0, removed = 0;
2657
2658 assert(err);
2659
2660 /* Look for a packed ref */
2661 for_each_string_list_item(refname, refnames) {
2662 if (get_packed_ref(refname->string)) {
2663 needs_repacking = 1;
2664 break;
2665 }
2666 }
2667
2668 /* Avoid locking if we have nothing to do */
2669 if (!needs_repacking)
2670 return 0; /* no refname exists in packed refs */
2671
2672 if (lock_packed_refs(0)) {
2673 unable_to_lock_message(git_path("packed-refs"), errno, err);
2674 return -1;
2675 }
2676 packed = get_packed_refs(&ref_cache);
2677
2678 /* Remove refnames from the cache */
2679 for_each_string_list_item(refname, refnames)
2680 if (remove_entry(packed, refname->string) != -1)
2681 removed = 1;
2682 if (!removed) {
2683 /*
2684 * All packed entries disappeared while we were
2685 * acquiring the lock.
2686 */
2687 rollback_packed_refs();
2688 return 0;
2689 }
2690
2691 /* Remove any other accumulated cruft */
2692 do_for_each_entry_in_dir(packed, 0, curate_packed_ref_fn, &refs_to_delete);
2693 for_each_string_list_item(ref_to_delete, &refs_to_delete) {
2694 if (remove_entry(packed, ref_to_delete->string) == -1)
2695 die("internal error");
2696 }
2697
2698 /* Write what remains */
2699 ret = commit_packed_refs();
2700 if (ret)
2701 strbuf_addf(err, "unable to overwrite old ref-pack file: %s",
2702 strerror(errno));
2703 return ret;
2704 }
2705
2706 static int delete_ref_loose(struct ref_lock *lock, int flag, struct strbuf *err)
2707 {
2708 assert(err);
2709
2710 if (!(flag & REF_ISPACKED) || flag & REF_ISSYMREF) {
2711 /*
2712 * loose. The loose file name is the same as the
2713 * lockfile name, minus ".lock":
2714 */
2715 char *loose_filename = get_locked_file_path(lock->lk);
2716 int res = unlink_or_msg(loose_filename, err);
2717 free(loose_filename);
2718 if (res)
2719 return 1;
2720 }
2721 return 0;
2722 }
2723
2724 int delete_ref(const char *refname, const unsigned char *sha1, int delopt)
2725 {
2726 struct ref_transaction *transaction;
2727 struct strbuf err = STRBUF_INIT;
2728
2729 transaction = ref_transaction_begin(&err);
2730 if (!transaction ||
2731 ref_transaction_delete(transaction, refname, sha1, delopt,
2732 sha1 && !is_null_sha1(sha1), NULL, &err) ||
2733 ref_transaction_commit(transaction, &err)) {
2734 error("%s", err.buf);
2735 ref_transaction_free(transaction);
2736 strbuf_release(&err);
2737 return 1;
2738 }
2739 ref_transaction_free(transaction);
2740 strbuf_release(&err);
2741 return 0;
2742 }
2743
2744 /*
2745 * People using contrib's git-new-workdir have .git/logs/refs ->
2746 * /some/other/path/.git/logs/refs, and that may live on another device.
2747 *
2748 * IOW, to avoid cross device rename errors, the temporary renamed log must
2749 * live into logs/refs.
2750 */
2751 #define TMP_RENAMED_LOG "logs/refs/.tmp-renamed-log"
2752
2753 static int rename_tmp_log(const char *newrefname)
2754 {
2755 int attempts_remaining = 4;
2756
2757 retry:
2758 switch (safe_create_leading_directories(git_path("logs/%s", newrefname))) {
2759 case SCLD_OK:
2760 break; /* success */
2761 case SCLD_VANISHED:
2762 if (--attempts_remaining > 0)
2763 goto retry;
2764 /* fall through */
2765 default:
2766 error("unable to create directory for %s", newrefname);
2767 return -1;
2768 }
2769
2770 if (rename(git_path(TMP_RENAMED_LOG), git_path("logs/%s", newrefname))) {
2771 if ((errno==EISDIR || errno==ENOTDIR) && --attempts_remaining > 0) {
2772 /*
2773 * rename(a, b) when b is an existing
2774 * directory ought to result in ISDIR, but
2775 * Solaris 5.8 gives ENOTDIR. Sheesh.
2776 */
2777 if (remove_empty_directories(git_path("logs/%s", newrefname))) {
2778 error("Directory not empty: logs/%s", newrefname);
2779 return -1;
2780 }
2781 goto retry;
2782 } else if (errno == ENOENT && --attempts_remaining > 0) {
2783 /*
2784 * Maybe another process just deleted one of
2785 * the directories in the path to newrefname.
2786 * Try again from the beginning.
2787 */
2788 goto retry;
2789 } else {
2790 error("unable to move logfile "TMP_RENAMED_LOG" to logs/%s: %s",
2791 newrefname, strerror(errno));
2792 return -1;
2793 }
2794 }
2795 return 0;
2796 }
2797
2798 static int rename_ref_available(const char *oldname, const char *newname)
2799 {
2800 struct string_list skip = STRING_LIST_INIT_NODUP;
2801 int ret;
2802
2803 string_list_insert(&skip, oldname);
2804 ret = is_refname_available(newname, &skip, get_packed_refs(&ref_cache))
2805 && is_refname_available(newname, &skip, get_loose_refs(&ref_cache));
2806 string_list_clear(&skip, 0);
2807 return ret;
2808 }
2809
2810 static int write_ref_sha1(struct ref_lock *lock, const unsigned char *sha1,
2811 const char *logmsg);
2812
2813 int rename_ref(const char *oldrefname, const char *newrefname, const char *logmsg)
2814 {
2815 unsigned char sha1[20], orig_sha1[20];
2816 int flag = 0, logmoved = 0;
2817 struct ref_lock *lock;
2818 struct stat loginfo;
2819 int log = !lstat(git_path("logs/%s", oldrefname), &loginfo);
2820 const char *symref = NULL;
2821
2822 if (log && S_ISLNK(loginfo.st_mode))
2823 return error("reflog for %s is a symlink", oldrefname);
2824
2825 symref = resolve_ref_unsafe(oldrefname, RESOLVE_REF_READING,
2826 orig_sha1, &flag);
2827 if (flag & REF_ISSYMREF)
2828 return error("refname %s is a symbolic ref, renaming it is not supported",
2829 oldrefname);
2830 if (!symref)
2831 return error("refname %s not found", oldrefname);
2832
2833 if (!rename_ref_available(oldrefname, newrefname))
2834 return 1;
2835
2836 if (log && rename(git_path("logs/%s", oldrefname), git_path(TMP_RENAMED_LOG)))
2837 return error("unable to move logfile logs/%s to "TMP_RENAMED_LOG": %s",
2838 oldrefname, strerror(errno));
2839
2840 if (delete_ref(oldrefname, orig_sha1, REF_NODEREF)) {
2841 error("unable to delete old %s", oldrefname);
2842 goto rollback;
2843 }
2844
2845 if (!read_ref_full(newrefname, RESOLVE_REF_READING, sha1, NULL) &&
2846 delete_ref(newrefname, sha1, REF_NODEREF)) {
2847 if (errno==EISDIR) {
2848 if (remove_empty_directories(git_path("%s", newrefname))) {
2849 error("Directory not empty: %s", newrefname);
2850 goto rollback;
2851 }
2852 } else {
2853 error("unable to delete existing %s", newrefname);
2854 goto rollback;
2855 }
2856 }
2857
2858 if (log && rename_tmp_log(newrefname))
2859 goto rollback;
2860
2861 logmoved = log;
2862
2863 lock = lock_ref_sha1_basic(newrefname, NULL, NULL, 0, NULL);
2864 if (!lock) {
2865 error("unable to lock %s for update", newrefname);
2866 goto rollback;
2867 }
2868 lock->force_write = 1;
2869 hashcpy(lock->old_sha1, orig_sha1);
2870 if (write_ref_sha1(lock, orig_sha1, logmsg)) {
2871 error("unable to write current sha1 into %s", newrefname);
2872 goto rollback;
2873 }
2874
2875 return 0;
2876
2877 rollback:
2878 lock = lock_ref_sha1_basic(oldrefname, NULL, NULL, 0, NULL);
2879 if (!lock) {
2880 error("unable to lock %s for rollback", oldrefname);
2881 goto rollbacklog;
2882 }
2883
2884 lock->force_write = 1;
2885 flag = log_all_ref_updates;
2886 log_all_ref_updates = 0;
2887 if (write_ref_sha1(lock, orig_sha1, NULL))
2888 error("unable to write current sha1 into %s", oldrefname);
2889 log_all_ref_updates = flag;
2890
2891 rollbacklog:
2892 if (logmoved && rename(git_path("logs/%s", newrefname), git_path("logs/%s", oldrefname)))
2893 error("unable to restore logfile %s from %s: %s",
2894 oldrefname, newrefname, strerror(errno));
2895 if (!logmoved && log &&
2896 rename(git_path(TMP_RENAMED_LOG), git_path("logs/%s", oldrefname)))
2897 error("unable to restore logfile %s from "TMP_RENAMED_LOG": %s",
2898 oldrefname, strerror(errno));
2899
2900 return 1;
2901 }
2902
2903 int close_ref(struct ref_lock *lock)
2904 {
2905 if (close_lock_file(lock->lk))
2906 return -1;
2907 lock->lock_fd = -1;
2908 return 0;
2909 }
2910
2911 int commit_ref(struct ref_lock *lock)
2912 {
2913 if (commit_lock_file(lock->lk))
2914 return -1;
2915 lock->lock_fd = -1;
2916 return 0;
2917 }
2918
2919 void unlock_ref(struct ref_lock *lock)
2920 {
2921 /* Do not free lock->lk -- atexit() still looks at them */
2922 if (lock->lk)
2923 rollback_lock_file(lock->lk);
2924 free(lock->ref_name);
2925 free(lock->orig_ref_name);
2926 free(lock);
2927 }
2928
2929 /*
2930 * copy the reflog message msg to buf, which has been allocated sufficiently
2931 * large, while cleaning up the whitespaces. Especially, convert LF to space,
2932 * because reflog file is one line per entry.
2933 */
2934 static int copy_msg(char *buf, const char *msg)
2935 {
2936 char *cp = buf;
2937 char c;
2938 int wasspace = 1;
2939
2940 *cp++ = '\t';
2941 while ((c = *msg++)) {
2942 if (wasspace && isspace(c))
2943 continue;
2944 wasspace = isspace(c);
2945 if (wasspace)
2946 c = ' ';
2947 *cp++ = c;
2948 }
2949 while (buf < cp && isspace(cp[-1]))
2950 cp--;
2951 *cp++ = '\n';
2952 return cp - buf;
2953 }
2954
2955 /* This function must set a meaningful errno on failure */
2956 int log_ref_setup(const char *refname, char *logfile, int bufsize)
2957 {
2958 int logfd, oflags = O_APPEND | O_WRONLY;
2959
2960 git_snpath(logfile, bufsize, "logs/%s", refname);
2961 if (log_all_ref_updates &&
2962 (starts_with(refname, "refs/heads/") ||
2963 starts_with(refname, "refs/remotes/") ||
2964 starts_with(refname, "refs/notes/") ||
2965 !strcmp(refname, "HEAD"))) {
2966 if (safe_create_leading_directories(logfile) < 0) {
2967 int save_errno = errno;
2968 error("unable to create directory for %s", logfile);
2969 errno = save_errno;
2970 return -1;
2971 }
2972 oflags |= O_CREAT;
2973 }
2974
2975 logfd = open(logfile, oflags, 0666);
2976 if (logfd < 0) {
2977 if (!(oflags & O_CREAT) && (errno == ENOENT || errno == EISDIR))
2978 return 0;
2979
2980 if (errno == EISDIR) {
2981 if (remove_empty_directories(logfile)) {
2982 int save_errno = errno;
2983 error("There are still logs under '%s'",
2984 logfile);
2985 errno = save_errno;
2986 return -1;
2987 }
2988 logfd = open(logfile, oflags, 0666);
2989 }
2990
2991 if (logfd < 0) {
2992 int save_errno = errno;
2993 error("Unable to append to %s: %s", logfile,
2994 strerror(errno));
2995 errno = save_errno;
2996 return -1;
2997 }
2998 }
2999
3000 adjust_shared_perm(logfile);
3001 close(logfd);
3002 return 0;
3003 }
3004
3005 static int log_ref_write(const char *refname, const unsigned char *old_sha1,
3006 const unsigned char *new_sha1, const char *msg)
3007 {
3008 int logfd, result, written, oflags = O_APPEND | O_WRONLY;
3009 unsigned maxlen, len;
3010 int msglen;
3011 char log_file[PATH_MAX];
3012 char *logrec;
3013 const char *committer;
3014
3015 if (log_all_ref_updates < 0)
3016 log_all_ref_updates = !is_bare_repository();
3017
3018 result = log_ref_setup(refname, log_file, sizeof(log_file));
3019 if (result)
3020 return result;
3021
3022 logfd = open(log_file, oflags);
3023 if (logfd < 0)
3024 return 0;
3025 msglen = msg ? strlen(msg) : 0;
3026 committer = git_committer_info(0);
3027 maxlen = strlen(committer) + msglen + 100;
3028 logrec = xmalloc(maxlen);
3029 len = sprintf(logrec, "%s %s %s\n",
3030 sha1_to_hex(old_sha1),
3031 sha1_to_hex(new_sha1),
3032 committer);
3033 if (msglen)
3034 len += copy_msg(logrec + len - 1, msg) - 1;
3035 written = len <= maxlen ? write_in_full(logfd, logrec, len) : -1;
3036 free(logrec);
3037 if (written != len) {
3038 int save_errno = errno;
3039 close(logfd);
3040 error("Unable to append to %s", log_file);
3041 errno = save_errno;
3042 return -1;
3043 }
3044 if (close(logfd)) {
3045 int save_errno = errno;
3046 error("Unable to append to %s", log_file);
3047 errno = save_errno;
3048 return -1;
3049 }
3050 return 0;
3051 }
3052
3053 int is_branch(const char *refname)
3054 {
3055 return !strcmp(refname, "HEAD") || starts_with(refname, "refs/heads/");
3056 }
3057
3058 /*
3059 * Write sha1 into the ref specified by the lock. Make sure that errno
3060 * is sane on error.
3061 */
3062 static int write_ref_sha1(struct ref_lock *lock,
3063 const unsigned char *sha1, const char *logmsg)
3064 {
3065 static char term = '\n';
3066 struct object *o;
3067
3068 if (!lock) {
3069 errno = EINVAL;
3070 return -1;
3071 }
3072 if (!lock->force_write && !hashcmp(lock->old_sha1, sha1)) {
3073 unlock_ref(lock);
3074 return 0;
3075 }
3076 o = parse_object(sha1);
3077 if (!o) {
3078 error("Trying to write ref %s with nonexistent object %s",
3079 lock->ref_name, sha1_to_hex(sha1));
3080 unlock_ref(lock);
3081 errno = EINVAL;
3082 return -1;
3083 }
3084 if (o->type != OBJ_COMMIT && is_branch(lock->ref_name)) {
3085 error("Trying to write non-commit object %s to branch %s",
3086 sha1_to_hex(sha1), lock->ref_name);
3087 unlock_ref(lock);
3088 errno = EINVAL;
3089 return -1;
3090 }
3091 if (write_in_full(lock->lock_fd, sha1_to_hex(sha1), 40) != 40 ||
3092 write_in_full(lock->lock_fd, &term, 1) != 1 ||
3093 close_ref(lock) < 0) {
3094 int save_errno = errno;
3095 error("Couldn't write %s", lock->lk->filename.buf);
3096 unlock_ref(lock);
3097 errno = save_errno;
3098 return -1;
3099 }
3100 clear_loose_ref_cache(&ref_cache);
3101 if (log_ref_write(lock->ref_name, lock->old_sha1, sha1, logmsg) < 0 ||
3102 (strcmp(lock->ref_name, lock->orig_ref_name) &&
3103 log_ref_write(lock->orig_ref_name, lock->old_sha1, sha1, logmsg) < 0)) {
3104 unlock_ref(lock);
3105 return -1;
3106 }
3107 if (strcmp(lock->orig_ref_name, "HEAD") != 0) {
3108 /*
3109 * Special hack: If a branch is updated directly and HEAD
3110 * points to it (may happen on the remote side of a push
3111 * for example) then logically the HEAD reflog should be
3112 * updated too.
3113 * A generic solution implies reverse symref information,
3114 * but finding all symrefs pointing to the given branch
3115 * would be rather costly for this rare event (the direct
3116 * update of a branch) to be worth it. So let's cheat and
3117 * check with HEAD only which should cover 99% of all usage
3118 * scenarios (even 100% of the default ones).
3119 */
3120 unsigned char head_sha1[20];
3121 int head_flag;
3122 const char *head_ref;
3123 head_ref = resolve_ref_unsafe("HEAD", RESOLVE_REF_READING,
3124 head_sha1, &head_flag);
3125 if (head_ref && (head_flag & REF_ISSYMREF) &&
3126 !strcmp(head_ref, lock->ref_name))
3127 log_ref_write("HEAD", lock->old_sha1, sha1, logmsg);
3128 }
3129 if (commit_ref(lock)) {
3130 error("Couldn't set %s", lock->ref_name);
3131 unlock_ref(lock);
3132 return -1;
3133 }
3134 unlock_ref(lock);
3135 return 0;
3136 }
3137
3138 int create_symref(const char *ref_target, const char *refs_heads_master,
3139 const char *logmsg)
3140 {
3141 const char *lockpath;
3142 char ref[1000];
3143 int fd, len, written;
3144 char *git_HEAD = git_pathdup("%s", ref_target);
3145 unsigned char old_sha1[20], new_sha1[20];
3146
3147 if (logmsg && read_ref(ref_target, old_sha1))
3148 hashclr(old_sha1);
3149
3150 if (safe_create_leading_directories(git_HEAD) < 0)
3151 return error("unable to create directory for %s", git_HEAD);
3152
3153 #ifndef NO_SYMLINK_HEAD
3154 if (prefer_symlink_refs) {
3155 unlink(git_HEAD);
3156 if (!symlink(refs_heads_master, git_HEAD))
3157 goto done;
3158 fprintf(stderr, "no symlink - falling back to symbolic ref\n");
3159 }
3160 #endif
3161
3162 len = snprintf(ref, sizeof(ref), "ref: %s\n", refs_heads_master);
3163 if (sizeof(ref) <= len) {
3164 error("refname too long: %s", refs_heads_master);
3165 goto error_free_return;
3166 }
3167 lockpath = mkpath("%s.lock", git_HEAD);
3168 fd = open(lockpath, O_CREAT | O_EXCL | O_WRONLY, 0666);
3169 if (fd < 0) {
3170 error("Unable to open %s for writing", lockpath);
3171 goto error_free_return;
3172 }
3173 written = write_in_full(fd, ref, len);
3174 if (close(fd) != 0 || written != len) {
3175 error("Unable to write to %s", lockpath);
3176 goto error_unlink_return;
3177 }
3178 if (rename(lockpath, git_HEAD) < 0) {
3179 error("Unable to create %s", git_HEAD);
3180 goto error_unlink_return;
3181 }
3182 if (adjust_shared_perm(git_HEAD)) {
3183 error("Unable to fix permissions on %s", lockpath);
3184 error_unlink_return:
3185 unlink_or_warn(lockpath);
3186 error_free_return:
3187 free(git_HEAD);
3188 return -1;
3189 }
3190
3191 #ifndef NO_SYMLINK_HEAD
3192 done:
3193 #endif
3194 if (logmsg && !read_ref(refs_heads_master, new_sha1))
3195 log_ref_write(ref_target, old_sha1, new_sha1, logmsg);
3196
3197 free(git_HEAD);
3198 return 0;
3199 }
3200
3201 struct read_ref_at_cb {
3202 const char *refname;
3203 unsigned long at_time;
3204 int cnt;
3205 int reccnt;
3206 unsigned char *sha1;
3207 int found_it;
3208
3209 unsigned char osha1[20];
3210 unsigned char nsha1[20];
3211 int tz;
3212 unsigned long date;
3213 char **msg;
3214 unsigned long *cutoff_time;
3215 int *cutoff_tz;
3216 int *cutoff_cnt;
3217 };
3218
3219 static int read_ref_at_ent(unsigned char *osha1, unsigned char *nsha1,
3220 const char *email, unsigned long timestamp, int tz,
3221 const char *message, void *cb_data)
3222 {
3223 struct read_ref_at_cb *cb = cb_data;
3224
3225 cb->reccnt++;
3226 cb->tz = tz;
3227 cb->date = timestamp;
3228
3229 if (timestamp <= cb->at_time || cb->cnt == 0) {
3230 if (cb->msg)
3231 *cb->msg = xstrdup(message);
3232 if (cb->cutoff_time)
3233 *cb->cutoff_time = timestamp;
3234 if (cb->cutoff_tz)
3235 *cb->cutoff_tz = tz;
3236 if (cb->cutoff_cnt)
3237 *cb->cutoff_cnt = cb->reccnt - 1;
3238 /*
3239 * we have not yet updated cb->[n|o]sha1 so they still
3240 * hold the values for the previous record.
3241 */
3242 if (!is_null_sha1(cb->osha1)) {
3243 hashcpy(cb->sha1, nsha1);
3244 if (hashcmp(cb->osha1, nsha1))
3245 warning("Log for ref %s has gap after %s.",
3246 cb->refname, show_date(cb->date, cb->tz, DATE_RFC2822));
3247 }
3248 else if (cb->date == cb->at_time)
3249 hashcpy(cb->sha1, nsha1);
3250 else if (hashcmp(nsha1, cb->sha1))
3251 warning("Log for ref %s unexpectedly ended on %s.",
3252 cb->refname, show_date(cb->date, cb->tz,
3253 DATE_RFC2822));
3254 hashcpy(cb->osha1, osha1);
3255 hashcpy(cb->nsha1, nsha1);
3256 cb->found_it = 1;
3257 return 1;
3258 }
3259 hashcpy(cb->osha1, osha1);
3260 hashcpy(cb->nsha1, nsha1);
3261 if (cb->cnt > 0)
3262 cb->cnt--;
3263 return 0;
3264 }
3265
3266 static int read_ref_at_ent_oldest(unsigned char *osha1, unsigned char *nsha1,
3267 const char *email, unsigned long timestamp,
3268 int tz, const char *message, void *cb_data)
3269 {
3270 struct read_ref_at_cb *cb = cb_data;
3271
3272 if (cb->msg)
3273 *cb->msg = xstrdup(message);
3274 if (cb->cutoff_time)
3275 *cb->cutoff_time = timestamp;
3276 if (cb->cutoff_tz)
3277 *cb->cutoff_tz = tz;
3278 if (cb->cutoff_cnt)
3279 *cb->cutoff_cnt = cb->reccnt;
3280 hashcpy(cb->sha1, osha1);
3281 if (is_null_sha1(cb->sha1))
3282 hashcpy(cb->sha1, nsha1);
3283 /* We just want the first entry */
3284 return 1;
3285 }
3286
3287 int read_ref_at(const char *refname, unsigned int flags, unsigned long at_time, int cnt,
3288 unsigned char *sha1, char **msg,
3289 unsigned long *cutoff_time, int *cutoff_tz, int *cutoff_cnt)
3290 {
3291 struct read_ref_at_cb cb;
3292
3293 memset(&cb, 0, sizeof(cb));
3294 cb.refname = refname;
3295 cb.at_time = at_time;
3296 cb.cnt = cnt;
3297 cb.msg = msg;
3298 cb.cutoff_time = cutoff_time;
3299 cb.cutoff_tz = cutoff_tz;
3300 cb.cutoff_cnt = cutoff_cnt;
3301 cb.sha1 = sha1;
3302
3303 for_each_reflog_ent_reverse(refname, read_ref_at_ent, &cb);
3304
3305 if (!cb.reccnt) {
3306 if (flags & GET_SHA1_QUIETLY)
3307 exit(128);
3308 else
3309 die("Log for %s is empty.", refname);
3310 }
3311 if (cb.found_it)
3312 return 0;
3313
3314 for_each_reflog_ent(refname, read_ref_at_ent_oldest, &cb);
3315
3316 return 1;
3317 }
3318
3319 int reflog_exists(const char *refname)
3320 {
3321 struct stat st;
3322
3323 return !lstat(git_path("logs/%s", refname), &st) &&
3324 S_ISREG(st.st_mode);
3325 }
3326
3327 int delete_reflog(const char *refname)
3328 {
3329 return remove_path(git_path("logs/%s", refname));
3330 }
3331
3332 static int show_one_reflog_ent(struct strbuf *sb, each_reflog_ent_fn fn, void *cb_data)
3333 {
3334 unsigned char osha1[20], nsha1[20];
3335 char *email_end, *message;
3336 unsigned long timestamp;
3337 int tz;
3338
3339 /* old SP new SP name <email> SP time TAB msg LF */
3340 if (sb->len < 83 || sb->buf[sb->len - 1] != '\n' ||
3341 get_sha1_hex(sb->buf, osha1) || sb->buf[40] != ' ' ||
3342 get_sha1_hex(sb->buf + 41, nsha1) || sb->buf[81] != ' ' ||
3343 !(email_end = strchr(sb->buf + 82, '>')) ||
3344 email_end[1] != ' ' ||
3345 !(timestamp = strtoul(email_end + 2, &message, 10)) ||
3346 !message || message[0] != ' ' ||
3347 (message[1] != '+' && message[1] != '-') ||
3348 !isdigit(message[2]) || !isdigit(message[3]) ||
3349 !isdigit(message[4]) || !isdigit(message[5]))
3350 return 0; /* corrupt? */
3351 email_end[1] = '\0';
3352 tz = strtol(message + 1, NULL, 10);
3353 if (message[6] != '\t')
3354 message += 6;
3355 else
3356 message += 7;
3357 return fn(osha1, nsha1, sb->buf + 82, timestamp, tz, message, cb_data);
3358 }
3359
3360 static char *find_beginning_of_line(char *bob, char *scan)
3361 {
3362 while (bob < scan && *(--scan) != '\n')
3363 ; /* keep scanning backwards */
3364 /*
3365 * Return either beginning of the buffer, or LF at the end of
3366 * the previous line.
3367 */
3368 return scan;
3369 }
3370
3371 int for_each_reflog_ent_reverse(const char *refname, each_reflog_ent_fn fn, void *cb_data)
3372 {
3373 struct strbuf sb = STRBUF_INIT;
3374 FILE *logfp;
3375 long pos;
3376 int ret = 0, at_tail = 1;
3377
3378 logfp = fopen(git_path("logs/%s", refname), "r");
3379 if (!logfp)
3380 return -1;
3381
3382 /* Jump to the end */
3383 if (fseek(logfp, 0, SEEK_END) < 0)
3384 return error("cannot seek back reflog for %s: %s",
3385 refname, strerror(errno));
3386 pos = ftell(logfp);
3387 while (!ret && 0 < pos) {
3388 int cnt;
3389 size_t nread;
3390 char buf[BUFSIZ];
3391 char *endp, *scanp;
3392
3393 /* Fill next block from the end */
3394 cnt = (sizeof(buf) < pos) ? sizeof(buf) : pos;
3395 if (fseek(logfp, pos - cnt, SEEK_SET))
3396 return error("cannot seek back reflog for %s: %s",
3397 refname, strerror(errno));
3398 nread = fread(buf, cnt, 1, logfp);
3399 if (nread != 1)
3400 return error("cannot read %d bytes from reflog for %s: %s",
3401 cnt, refname, strerror(errno));
3402 pos -= cnt;
3403
3404 scanp = endp = buf + cnt;
3405 if (at_tail && scanp[-1] == '\n')
3406 /* Looking at the final LF at the end of the file */
3407 scanp--;
3408 at_tail = 0;
3409
3410 while (buf < scanp) {
3411 /*
3412 * terminating LF of the previous line, or the beginning
3413 * of the buffer.
3414 */
3415 char *bp;
3416
3417 bp = find_beginning_of_line(buf, scanp);
3418
3419 if (*bp == '\n') {
3420 /*
3421 * The newline is the end of the previous line,
3422 * so we know we have complete line starting
3423 * at (bp + 1). Prefix it onto any prior data
3424 * we collected for the line and process it.
3425 */
3426 strbuf_splice(&sb, 0, 0, bp + 1, endp - (bp + 1));
3427 scanp = bp;
3428 endp = bp + 1;
3429 ret = show_one_reflog_ent(&sb, fn, cb_data);
3430 strbuf_reset(&sb);
3431 if (ret)
3432 break;
3433 } else if (!pos) {
3434 /*
3435 * We are at the start of the buffer, and the
3436 * start of the file; there is no previous
3437 * line, and we have everything for this one.
3438 * Process it, and we can end the loop.
3439 */
3440 strbuf_splice(&sb, 0, 0, buf, endp - buf);
3441 ret = show_one_reflog_ent(&sb, fn, cb_data);
3442 strbuf_reset(&sb);
3443 break;
3444 }
3445
3446 if (bp == buf) {
3447 /*
3448 * We are at the start of the buffer, and there
3449 * is more file to read backwards. Which means
3450 * we are in the middle of a line. Note that we
3451 * may get here even if *bp was a newline; that
3452 * just means we are at the exact end of the
3453 * previous line, rather than some spot in the
3454 * middle.
3455 *
3456 * Save away what we have to be combined with
3457 * the data from the next read.
3458 */
3459 strbuf_splice(&sb, 0, 0, buf, endp - buf);
3460 break;
3461 }
3462 }
3463
3464 }
3465 if (!ret && sb.len)
3466 die("BUG: reverse reflog parser had leftover data");
3467
3468 fclose(logfp);
3469 strbuf_release(&sb);
3470 return ret;
3471 }
3472
3473 int for_each_reflog_ent(const char *refname, each_reflog_ent_fn fn, void *cb_data)
3474 {
3475 FILE *logfp;
3476 struct strbuf sb = STRBUF_INIT;
3477 int ret = 0;
3478
3479 logfp = fopen(git_path("logs/%s", refname), "r");
3480 if (!logfp)
3481 return -1;
3482
3483 while (!ret && !strbuf_getwholeline(&sb, logfp, '\n'))
3484 ret = show_one_reflog_ent(&sb, fn, cb_data);
3485 fclose(logfp);
3486 strbuf_release(&sb);
3487 return ret;
3488 }
3489 /*
3490 * Call fn for each reflog in the namespace indicated by name. name
3491 * must be empty or end with '/'. Name will be used as a scratch
3492 * space, but its contents will be restored before return.
3493 */
3494 static int do_for_each_reflog(struct strbuf *name, each_ref_fn fn, void *cb_data)
3495 {
3496 DIR *d = opendir(git_path("logs/%s", name->buf));
3497 int retval = 0;
3498 struct dirent *de;
3499 int oldlen = name->len;
3500
3501 if (!d)
3502 return name->len ? errno : 0;
3503
3504 while ((de = readdir(d)) != NULL) {
3505 struct stat st;
3506
3507 if (de->d_name[0] == '.')
3508 continue;
3509 if (ends_with(de->d_name, ".lock"))
3510 continue;
3511 strbuf_addstr(name, de->d_name);
3512 if (stat(git_path("logs/%s", name->buf), &st) < 0) {
3513 ; /* silently ignore */
3514 } else {
3515 if (S_ISDIR(st.st_mode)) {
3516 strbuf_addch(name, '/');
3517 retval = do_for_each_reflog(name, fn, cb_data);
3518 } else {
3519 unsigned char sha1[20];
3520 if (read_ref_full(name->buf, 0, sha1, NULL))
3521 retval = error("bad ref for %s", name->buf);
3522 else
3523 retval = fn(name->buf, sha1, 0, cb_data);
3524 }
3525 if (retval)
3526 break;
3527 }
3528 strbuf_setlen(name, oldlen);
3529 }
3530 closedir(d);
3531 return retval;
3532 }
3533
3534 int for_each_reflog(each_ref_fn fn, void *cb_data)
3535 {
3536 int retval;
3537 struct strbuf name;
3538 strbuf_init(&name, PATH_MAX);
3539 retval = do_for_each_reflog(&name, fn, cb_data);
3540 strbuf_release(&name);
3541 return retval;
3542 }
3543
3544 /**
3545 * Information needed for a single ref update. Set new_sha1 to the
3546 * new value or to zero to delete the ref. To check the old value
3547 * while locking the ref, set have_old to 1 and set old_sha1 to the
3548 * value or to zero to ensure the ref does not exist before update.
3549 */
3550 struct ref_update {
3551 unsigned char new_sha1[20];
3552 unsigned char old_sha1[20];
3553 int flags; /* REF_NODEREF? */
3554 int have_old; /* 1 if old_sha1 is valid, 0 otherwise */
3555 struct ref_lock *lock;
3556 int type;
3557 char *msg;
3558 const char refname[FLEX_ARRAY];
3559 };
3560
3561 /*
3562 * Transaction states.
3563 * OPEN: The transaction is in a valid state and can accept new updates.
3564 * An OPEN transaction can be committed.
3565 * CLOSED: A closed transaction is no longer active and no other operations
3566 * than free can be used on it in this state.
3567 * A transaction can either become closed by successfully committing
3568 * an active transaction or if there is a failure while building
3569 * the transaction thus rendering it failed/inactive.
3570 */
3571 enum ref_transaction_state {
3572 REF_TRANSACTION_OPEN = 0,
3573 REF_TRANSACTION_CLOSED = 1
3574 };
3575
3576 /*
3577 * Data structure for holding a reference transaction, which can
3578 * consist of checks and updates to multiple references, carried out
3579 * as atomically as possible. This structure is opaque to callers.
3580 */
3581 struct ref_transaction {
3582 struct ref_update **updates;
3583 size_t alloc;
3584 size_t nr;
3585 enum ref_transaction_state state;
3586 };
3587
3588 struct ref_transaction *ref_transaction_begin(struct strbuf *err)
3589 {
3590 assert(err);
3591
3592 return xcalloc(1, sizeof(struct ref_transaction));
3593 }
3594
3595 void ref_transaction_free(struct ref_transaction *transaction)
3596 {
3597 int i;
3598
3599 if (!transaction)
3600 return;
3601
3602 for (i = 0; i < transaction->nr; i++) {
3603 free(transaction->updates[i]->msg);
3604 free(transaction->updates[i]);
3605 }
3606 free(transaction->updates);
3607 free(transaction);
3608 }
3609
3610 static struct ref_update *add_update(struct ref_transaction *transaction,
3611 const char *refname)
3612 {
3613 size_t len = strlen(refname);
3614 struct ref_update *update = xcalloc(1, sizeof(*update) + len + 1);
3615
3616 strcpy((char *)update->refname, refname);
3617 ALLOC_GROW(transaction->updates, transaction->nr + 1, transaction->alloc);
3618 transaction->updates[transaction->nr++] = update;
3619 return update;
3620 }
3621
3622 int ref_transaction_update(struct ref_transaction *transaction,
3623 const char *refname,
3624 const unsigned char *new_sha1,
3625 const unsigned char *old_sha1,
3626 int flags, int have_old, const char *msg,
3627 struct strbuf *err)
3628 {
3629 struct ref_update *update;
3630
3631 assert(err);
3632
3633 if (transaction->state != REF_TRANSACTION_OPEN)
3634 die("BUG: update called for transaction that is not open");
3635
3636 if (have_old && !old_sha1)
3637 die("BUG: have_old is true but old_sha1 is NULL");
3638
3639 if (!is_null_sha1(new_sha1) &&
3640 check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
3641 strbuf_addf(err, "refusing to update ref with bad name %s",
3642 refname);
3643 return -1;
3644 }
3645
3646 update = add_update(transaction, refname);
3647 hashcpy(update->new_sha1, new_sha1);
3648 update->flags = flags;
3649 update->have_old = have_old;
3650 if (have_old)
3651 hashcpy(update->old_sha1, old_sha1);
3652 if (msg)
3653 update->msg = xstrdup(msg);
3654 return 0;
3655 }
3656
3657 int ref_transaction_create(struct ref_transaction *transaction,
3658 const char *refname,
3659 const unsigned char *new_sha1,
3660 int flags, const char *msg,
3661 struct strbuf *err)
3662 {
3663 struct ref_update *update;
3664
3665 assert(err);
3666
3667 if (transaction->state != REF_TRANSACTION_OPEN)
3668 die("BUG: create called for transaction that is not open");
3669
3670 if (!new_sha1 || is_null_sha1(new_sha1))
3671 die("BUG: create ref with null new_sha1");
3672
3673 if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
3674 strbuf_addf(err, "refusing to create ref with bad name %s",
3675 refname);
3676 return -1;
3677 }
3678
3679 update = add_update(transaction, refname);
3680
3681 hashcpy(update->new_sha1, new_sha1);
3682 hashclr(update->old_sha1);
3683 update->flags = flags;
3684 update->have_old = 1;
3685 if (msg)
3686 update->msg = xstrdup(msg);
3687 return 0;
3688 }
3689
3690 int ref_transaction_delete(struct ref_transaction *transaction,
3691 const char *refname,
3692 const unsigned char *old_sha1,
3693 int flags, int have_old, const char *msg,
3694 struct strbuf *err)
3695 {
3696 struct ref_update *update;
3697
3698 assert(err);
3699
3700 if (transaction->state != REF_TRANSACTION_OPEN)
3701 die("BUG: delete called for transaction that is not open");
3702
3703 if (have_old && !old_sha1)
3704 die("BUG: have_old is true but old_sha1 is NULL");
3705
3706 update = add_update(transaction, refname);
3707 update->flags = flags;
3708 update->have_old = have_old;
3709 if (have_old) {
3710 assert(!is_null_sha1(old_sha1));
3711 hashcpy(update->old_sha1, old_sha1);
3712 }
3713 if (msg)
3714 update->msg = xstrdup(msg);
3715 return 0;
3716 }
3717
3718 int update_ref(const char *action, const char *refname,
3719 const unsigned char *sha1, const unsigned char *oldval,
3720 int flags, enum action_on_err onerr)
3721 {
3722 struct ref_transaction *t;
3723 struct strbuf err = STRBUF_INIT;
3724
3725 t = ref_transaction_begin(&err);
3726 if (!t ||
3727 ref_transaction_update(t, refname, sha1, oldval, flags,
3728 !!oldval, action, &err) ||
3729 ref_transaction_commit(t, &err)) {
3730 const char *str = "update_ref failed for ref '%s': %s";
3731
3732 ref_transaction_free(t);
3733 switch (onerr) {
3734 case UPDATE_REFS_MSG_ON_ERR:
3735 error(str, refname, err.buf);
3736 break;
3737 case UPDATE_REFS_DIE_ON_ERR:
3738 die(str, refname, err.buf);
3739 break;
3740 case UPDATE_REFS_QUIET_ON_ERR:
3741 break;
3742 }
3743 strbuf_release(&err);
3744 return 1;
3745 }
3746 strbuf_release(&err);
3747 ref_transaction_free(t);
3748 return 0;
3749 }
3750
3751 static int ref_update_compare(const void *r1, const void *r2)
3752 {
3753 const struct ref_update * const *u1 = r1;
3754 const struct ref_update * const *u2 = r2;
3755 return strcmp((*u1)->refname, (*u2)->refname);
3756 }
3757
3758 static int ref_update_reject_duplicates(struct ref_update **updates, int n,
3759 struct strbuf *err)
3760 {
3761 int i;
3762
3763 assert(err);
3764
3765 for (i = 1; i < n; i++)
3766 if (!strcmp(updates[i - 1]->refname, updates[i]->refname)) {
3767 strbuf_addf(err,
3768 "Multiple updates for ref '%s' not allowed.",
3769 updates[i]->refname);
3770 return 1;
3771 }
3772 return 0;
3773 }
3774
3775 int ref_transaction_commit(struct ref_transaction *transaction,
3776 struct strbuf *err)
3777 {
3778 int ret = 0, i;
3779 int n = transaction->nr;
3780 struct ref_update **updates = transaction->updates;
3781 struct string_list refs_to_delete = STRING_LIST_INIT_NODUP;
3782 struct string_list_item *ref_to_delete;
3783
3784 assert(err);
3785
3786 if (transaction->state != REF_TRANSACTION_OPEN)
3787 die("BUG: commit called for transaction that is not open");
3788
3789 if (!n) {
3790 transaction->state = REF_TRANSACTION_CLOSED;
3791 return 0;
3792 }
3793
3794 /* Copy, sort, and reject duplicate refs */
3795 qsort(updates, n, sizeof(*updates), ref_update_compare);
3796 if (ref_update_reject_duplicates(updates, n, err)) {
3797 ret = TRANSACTION_GENERIC_ERROR;
3798 goto cleanup;
3799 }
3800
3801 /* Acquire all locks while verifying old values */
3802 for (i = 0; i < n; i++) {
3803 struct ref_update *update = updates[i];
3804 int flags = update->flags;
3805
3806 if (is_null_sha1(update->new_sha1))
3807 flags |= REF_DELETING;
3808 update->lock = lock_ref_sha1_basic(update->refname,
3809 (update->have_old ?
3810 update->old_sha1 :
3811 NULL),
3812 NULL,
3813 flags,
3814 &update->type);
3815 if (!update->lock) {
3816 ret = (errno == ENOTDIR)
3817 ? TRANSACTION_NAME_CONFLICT
3818 : TRANSACTION_GENERIC_ERROR;
3819 strbuf_addf(err, "Cannot lock the ref '%s'.",
3820 update->refname);
3821 goto cleanup;
3822 }
3823 }
3824
3825 /* Perform updates first so live commits remain referenced */
3826 for (i = 0; i < n; i++) {
3827 struct ref_update *update = updates[i];
3828
3829 if (!is_null_sha1(update->new_sha1)) {
3830 if (write_ref_sha1(update->lock, update->new_sha1,
3831 update->msg)) {
3832 update->lock = NULL; /* freed by write_ref_sha1 */
3833 strbuf_addf(err, "Cannot update the ref '%s'.",
3834 update->refname);
3835 ret = TRANSACTION_GENERIC_ERROR;
3836 goto cleanup;
3837 }
3838 update->lock = NULL; /* freed by write_ref_sha1 */
3839 }
3840 }
3841
3842 /* Perform deletes now that updates are safely completed */
3843 for (i = 0; i < n; i++) {
3844 struct ref_update *update = updates[i];
3845
3846 if (update->lock) {
3847 if (delete_ref_loose(update->lock, update->type, err)) {
3848 ret = TRANSACTION_GENERIC_ERROR;
3849 goto cleanup;
3850 }
3851
3852 if (!(update->flags & REF_ISPRUNING))
3853 string_list_append(&refs_to_delete,
3854 update->lock->ref_name);
3855 }
3856 }
3857
3858 if (repack_without_refs(&refs_to_delete, err)) {
3859 ret = TRANSACTION_GENERIC_ERROR;
3860 goto cleanup;
3861 }
3862 for_each_string_list_item(ref_to_delete, &refs_to_delete)
3863 unlink_or_warn(git_path("logs/%s", ref_to_delete->string));
3864 clear_loose_ref_cache(&ref_cache);
3865
3866 cleanup:
3867 transaction->state = REF_TRANSACTION_CLOSED;
3868
3869 for (i = 0; i < n; i++)
3870 if (updates[i]->lock)
3871 unlock_ref(updates[i]->lock);
3872 string_list_clear(&refs_to_delete, 0);
3873 return ret;
3874 }
3875
3876 char *shorten_unambiguous_ref(const char *refname, int strict)
3877 {
3878 int i;
3879 static char **scanf_fmts;
3880 static int nr_rules;
3881 char *short_name;
3882
3883 if (!nr_rules) {
3884 /*
3885 * Pre-generate scanf formats from ref_rev_parse_rules[].
3886 * Generate a format suitable for scanf from a
3887 * ref_rev_parse_rules rule by interpolating "%s" at the
3888 * location of the "%.*s".
3889 */
3890 size_t total_len = 0;
3891 size_t offset = 0;
3892
3893 /* the rule list is NULL terminated, count them first */
3894 for (nr_rules = 0; ref_rev_parse_rules[nr_rules]; nr_rules++)
3895 /* -2 for strlen("%.*s") - strlen("%s"); +1 for NUL */
3896 total_len += strlen(ref_rev_parse_rules[nr_rules]) - 2 + 1;
3897
3898 scanf_fmts = xmalloc(nr_rules * sizeof(char *) + total_len);
3899
3900 offset = 0;
3901 for (i = 0; i < nr_rules; i++) {
3902 assert(offset < total_len);
3903 scanf_fmts[i] = (char *)&scanf_fmts[nr_rules] + offset;
3904 offset += snprintf(scanf_fmts[i], total_len - offset,
3905 ref_rev_parse_rules[i], 2, "%s") + 1;
3906 }
3907 }
3908
3909 /* bail out if there are no rules */
3910 if (!nr_rules)
3911 return xstrdup(refname);