refs.c: change some "flags" to "unsigned int"
[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 struct ref_lock {
10 char *ref_name;
11 char *orig_ref_name;
12 struct lock_file *lk;
13 unsigned char old_sha1[20];
14 int lock_fd;
15 int force_write;
16 };
17
18 /*
19 * How to handle various characters in refnames:
20 * 0: An acceptable character for refs
21 * 1: End-of-component
22 * 2: ., look for a preceding . to reject .. in refs
23 * 3: {, look for a preceding @ to reject @{ in refs
24 * 4: A bad character: ASCII control characters, "~", "^", ":" or SP
25 */
26 static unsigned char refname_disposition[256] = {
27 1, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
28 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
29 4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4, 0, 0, 0, 2, 1,
30 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4, 0, 0, 0, 0, 4,
31 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
32 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4, 4, 0, 4, 0,
33 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
34 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 3, 0, 0, 4, 4
35 };
36
37 /*
38 * Flag passed to lock_ref_sha1_basic() telling it to tolerate broken
39 * refs (i.e., because the reference is about to be deleted anyway).
40 */
41 #define REF_DELETING 0x02
42
43 /*
44 * Used as a flag to ref_transaction_delete when a loose ref is being
45 * pruned.
46 */
47 #define REF_ISPRUNING 0x04
48
49 /*
50 * Try to read one refname component from the front of refname.
51 * Return the length of the component found, or -1 if the component is
52 * not legal. It is legal if it is something reasonable to have under
53 * ".git/refs/"; We do not like it if:
54 *
55 * - any path component of it begins with ".", or
56 * - it has double dots "..", or
57 * - it has ASCII control character, "~", "^", ":" or SP, anywhere, or
58 * - it ends with a "/".
59 * - it ends with ".lock"
60 * - it contains a "\" (backslash)
61 */
62 static int check_refname_component(const char *refname, int flags)
63 {
64 const char *cp;
65 char last = '\0';
66
67 for (cp = refname; ; cp++) {
68 int ch = *cp & 255;
69 unsigned char disp = refname_disposition[ch];
70 switch (disp) {
71 case 1:
72 goto out;
73 case 2:
74 if (last == '.')
75 return -1; /* Refname contains "..". */
76 break;
77 case 3:
78 if (last == '@')
79 return -1; /* Refname contains "@{". */
80 break;
81 case 4:
82 return -1;
83 }
84 last = ch;
85 }
86 out:
87 if (cp == refname)
88 return 0; /* Component has zero length. */
89 if (refname[0] == '.')
90 return -1; /* Component starts with '.'. */
91 if (cp - refname >= LOCK_SUFFIX_LEN &&
92 !memcmp(cp - LOCK_SUFFIX_LEN, LOCK_SUFFIX, LOCK_SUFFIX_LEN))
93 return -1; /* Refname ends with ".lock". */
94 return cp - refname;
95 }
96
97 int check_refname_format(const char *refname, int flags)
98 {
99 int component_len, component_count = 0;
100
101 if (!strcmp(refname, "@"))
102 /* Refname is a single character '@'. */
103 return -1;
104
105 while (1) {
106 /* We are at the start of a path component. */
107 component_len = check_refname_component(refname, flags);
108 if (component_len <= 0) {
109 if ((flags & REFNAME_REFSPEC_PATTERN) &&
110 refname[0] == '*' &&
111 (refname[1] == '\0' || refname[1] == '/')) {
112 /* Accept one wildcard as a full refname component. */
113 flags &= ~REFNAME_REFSPEC_PATTERN;
114 component_len = 1;
115 } else {
116 return -1;
117 }
118 }
119 component_count++;
120 if (refname[component_len] == '\0')
121 break;
122 /* Skip to next component. */
123 refname += component_len + 1;
124 }
125
126 if (refname[component_len - 1] == '.')
127 return -1; /* Refname ends with '.'. */
128 if (!(flags & REFNAME_ALLOW_ONELEVEL) && component_count < 2)
129 return -1; /* Refname has only one component. */
130 return 0;
131 }
132
133 struct ref_entry;
134
135 /*
136 * Information used (along with the information in ref_entry) to
137 * describe a single cached reference. This data structure only
138 * occurs embedded in a union in struct ref_entry, and only when
139 * (ref_entry->flag & REF_DIR) is zero.
140 */
141 struct ref_value {
142 /*
143 * The name of the object to which this reference resolves
144 * (which may be a tag object). If REF_ISBROKEN, this is
145 * null. If REF_ISSYMREF, then this is the name of the object
146 * referred to by the last reference in the symlink chain.
147 */
148 unsigned char sha1[20];
149
150 /*
151 * If REF_KNOWS_PEELED, then this field holds the peeled value
152 * of this reference, or null if the reference is known not to
153 * be peelable. See the documentation for peel_ref() for an
154 * exact definition of "peelable".
155 */
156 unsigned char peeled[20];
157 };
158
159 struct ref_cache;
160
161 /*
162 * Information used (along with the information in ref_entry) to
163 * describe a level in the hierarchy of references. This data
164 * structure only occurs embedded in a union in struct ref_entry, and
165 * only when (ref_entry.flag & REF_DIR) is set. In that case,
166 * (ref_entry.flag & REF_INCOMPLETE) determines whether the references
167 * in the directory have already been read:
168 *
169 * (ref_entry.flag & REF_INCOMPLETE) unset -- a directory of loose
170 * or packed references, already read.
171 *
172 * (ref_entry.flag & REF_INCOMPLETE) set -- a directory of loose
173 * references that hasn't been read yet (nor has any of its
174 * subdirectories).
175 *
176 * Entries within a directory are stored within a growable array of
177 * pointers to ref_entries (entries, nr, alloc). Entries 0 <= i <
178 * sorted are sorted by their component name in strcmp() order and the
179 * remaining entries are unsorted.
180 *
181 * Loose references are read lazily, one directory at a time. When a
182 * directory of loose references is read, then all of the references
183 * in that directory are stored, and REF_INCOMPLETE stubs are created
184 * for any subdirectories, but the subdirectories themselves are not
185 * read. The reading is triggered by get_ref_dir().
186 */
187 struct ref_dir {
188 int nr, alloc;
189
190 /*
191 * Entries with index 0 <= i < sorted are sorted by name. New
192 * entries are appended to the list unsorted, and are sorted
193 * only when required; thus we avoid the need to sort the list
194 * after the addition of every reference.
195 */
196 int sorted;
197
198 /* A pointer to the ref_cache that contains this ref_dir. */
199 struct ref_cache *ref_cache;
200
201 struct ref_entry **entries;
202 };
203
204 /*
205 * Bit values for ref_entry::flag. REF_ISSYMREF=0x01,
206 * REF_ISPACKED=0x02, REF_ISBROKEN=0x04 and REF_BAD_NAME=0x08 are
207 * public values; see refs.h.
208 */
209
210 /*
211 * The field ref_entry->u.value.peeled of this value entry contains
212 * the correct peeled value for the reference, which might be
213 * null_sha1 if the reference is not a tag or if it is broken.
214 */
215 #define REF_KNOWS_PEELED 0x10
216
217 /* ref_entry represents a directory of references */
218 #define REF_DIR 0x20
219
220 /*
221 * Entry has not yet been read from disk (used only for REF_DIR
222 * entries representing loose references)
223 */
224 #define REF_INCOMPLETE 0x40
225
226 /*
227 * A ref_entry represents either a reference or a "subdirectory" of
228 * references.
229 *
230 * Each directory in the reference namespace is represented by a
231 * ref_entry with (flags & REF_DIR) set and containing a subdir member
232 * that holds the entries in that directory that have been read so
233 * far. If (flags & REF_INCOMPLETE) is set, then the directory and
234 * its subdirectories haven't been read yet. REF_INCOMPLETE is only
235 * used for loose reference directories.
236 *
237 * References are represented by a ref_entry with (flags & REF_DIR)
238 * unset and a value member that describes the reference's value. The
239 * flag member is at the ref_entry level, but it is also needed to
240 * interpret the contents of the value field (in other words, a
241 * ref_value object is not very much use without the enclosing
242 * ref_entry).
243 *
244 * Reference names cannot end with slash and directories' names are
245 * always stored with a trailing slash (except for the top-level
246 * directory, which is always denoted by ""). This has two nice
247 * consequences: (1) when the entries in each subdir are sorted
248 * lexicographically by name (as they usually are), the references in
249 * a whole tree can be generated in lexicographic order by traversing
250 * the tree in left-to-right, depth-first order; (2) the names of
251 * references and subdirectories cannot conflict, and therefore the
252 * presence of an empty subdirectory does not block the creation of a
253 * similarly-named reference. (The fact that reference names with the
254 * same leading components can conflict *with each other* is a
255 * separate issue that is regulated by is_refname_available().)
256 *
257 * Please note that the name field contains the fully-qualified
258 * reference (or subdirectory) name. Space could be saved by only
259 * storing the relative names. But that would require the full names
260 * to be generated on the fly when iterating in do_for_each_ref(), and
261 * would break callback functions, who have always been able to assume
262 * that the name strings that they are passed will not be freed during
263 * the iteration.
264 */
265 struct ref_entry {
266 unsigned char flag; /* ISSYMREF? ISPACKED? */
267 union {
268 struct ref_value value; /* if not (flags&REF_DIR) */
269 struct ref_dir subdir; /* if (flags&REF_DIR) */
270 } u;
271 /*
272 * The full name of the reference (e.g., "refs/heads/master")
273 * or the full name of the directory with a trailing slash
274 * (e.g., "refs/heads/"):
275 */
276 char name[FLEX_ARRAY];
277 };
278
279 static void read_loose_refs(const char *dirname, struct ref_dir *dir);
280
281 static struct ref_dir *get_ref_dir(struct ref_entry *entry)
282 {
283 struct ref_dir *dir;
284 assert(entry->flag & REF_DIR);
285 dir = &entry->u.subdir;
286 if (entry->flag & REF_INCOMPLETE) {
287 read_loose_refs(entry->name, dir);
288 entry->flag &= ~REF_INCOMPLETE;
289 }
290 return dir;
291 }
292
293 /*
294 * Check if a refname is safe.
295 * For refs that start with "refs/" we consider it safe as long they do
296 * not try to resolve to outside of refs/.
297 *
298 * For all other refs we only consider them safe iff they only contain
299 * upper case characters and '_' (like "HEAD" AND "MERGE_HEAD", and not like
300 * "config").
301 */
302 static int refname_is_safe(const char *refname)
303 {
304 if (starts_with(refname, "refs/")) {
305 char *buf;
306 int result;
307
308 buf = xmalloc(strlen(refname) + 1);
309 /*
310 * Does the refname try to escape refs/?
311 * For example: refs/foo/../bar is safe but refs/foo/../../bar
312 * is not.
313 */
314 result = !normalize_path_copy(buf, refname + strlen("refs/"));
315 free(buf);
316 return result;
317 }
318 while (*refname) {
319 if (!isupper(*refname) && *refname != '_')
320 return 0;
321 refname++;
322 }
323 return 1;
324 }
325
326 static struct ref_entry *create_ref_entry(const char *refname,
327 const unsigned char *sha1, int flag,
328 int check_name)
329 {
330 int len;
331 struct ref_entry *ref;
332
333 if (check_name &&
334 check_refname_format(refname, REFNAME_ALLOW_ONELEVEL))
335 die("Reference has invalid format: '%s'", refname);
336 if (!check_name && !refname_is_safe(refname))
337 die("Reference has invalid name: '%s'", refname);
338 len = strlen(refname) + 1;
339 ref = xmalloc(sizeof(struct ref_entry) + len);
340 hashcpy(ref->u.value.sha1, sha1);
341 hashclr(ref->u.value.peeled);
342 memcpy(ref->name, refname, len);
343 ref->flag = flag;
344 return ref;
345 }
346
347 static void clear_ref_dir(struct ref_dir *dir);
348
349 static void free_ref_entry(struct ref_entry *entry)
350 {
351 if (entry->flag & REF_DIR) {
352 /*
353 * Do not use get_ref_dir() here, as that might
354 * trigger the reading of loose refs.
355 */
356 clear_ref_dir(&entry->u.subdir);
357 }
358 free(entry);
359 }
360
361 /*
362 * Add a ref_entry to the end of dir (unsorted). Entry is always
363 * stored directly in dir; no recursion into subdirectories is
364 * done.
365 */
366 static void add_entry_to_dir(struct ref_dir *dir, struct ref_entry *entry)
367 {
368 ALLOC_GROW(dir->entries, dir->nr + 1, dir->alloc);
369 dir->entries[dir->nr++] = entry;
370 /* optimize for the case that entries are added in order */
371 if (dir->nr == 1 ||
372 (dir->nr == dir->sorted + 1 &&
373 strcmp(dir->entries[dir->nr - 2]->name,
374 dir->entries[dir->nr - 1]->name) < 0))
375 dir->sorted = dir->nr;
376 }
377
378 /*
379 * Clear and free all entries in dir, recursively.
380 */
381 static void clear_ref_dir(struct ref_dir *dir)
382 {
383 int i;
384 for (i = 0; i < dir->nr; i++)
385 free_ref_entry(dir->entries[i]);
386 free(dir->entries);
387 dir->sorted = dir->nr = dir->alloc = 0;
388 dir->entries = NULL;
389 }
390
391 /*
392 * Create a struct ref_entry object for the specified dirname.
393 * dirname is the name of the directory with a trailing slash (e.g.,
394 * "refs/heads/") or "" for the top-level directory.
395 */
396 static struct ref_entry *create_dir_entry(struct ref_cache *ref_cache,
397 const char *dirname, size_t len,
398 int incomplete)
399 {
400 struct ref_entry *direntry;
401 direntry = xcalloc(1, sizeof(struct ref_entry) + len + 1);
402 memcpy(direntry->name, dirname, len);
403 direntry->name[len] = '\0';
404 direntry->u.subdir.ref_cache = ref_cache;
405 direntry->flag = REF_DIR | (incomplete ? REF_INCOMPLETE : 0);
406 return direntry;
407 }
408
409 static int ref_entry_cmp(const void *a, const void *b)
410 {
411 struct ref_entry *one = *(struct ref_entry **)a;
412 struct ref_entry *two = *(struct ref_entry **)b;
413 return strcmp(one->name, two->name);
414 }
415
416 static void sort_ref_dir(struct ref_dir *dir);
417
418 struct string_slice {
419 size_t len;
420 const char *str;
421 };
422
423 static int ref_entry_cmp_sslice(const void *key_, const void *ent_)
424 {
425 const struct string_slice *key = key_;
426 const struct ref_entry *ent = *(const struct ref_entry * const *)ent_;
427 int cmp = strncmp(key->str, ent->name, key->len);
428 if (cmp)
429 return cmp;
430 return '\0' - (unsigned char)ent->name[key->len];
431 }
432
433 /*
434 * Return the index of the entry with the given refname from the
435 * ref_dir (non-recursively), sorting dir if necessary. Return -1 if
436 * no such entry is found. dir must already be complete.
437 */
438 static int search_ref_dir(struct ref_dir *dir, const char *refname, size_t len)
439 {
440 struct ref_entry **r;
441 struct string_slice key;
442
443 if (refname == NULL || !dir->nr)
444 return -1;
445
446 sort_ref_dir(dir);
447 key.len = len;
448 key.str = refname;
449 r = bsearch(&key, dir->entries, dir->nr, sizeof(*dir->entries),
450 ref_entry_cmp_sslice);
451
452 if (r == NULL)
453 return -1;
454
455 return r - dir->entries;
456 }
457
458 /*
459 * Search for a directory entry directly within dir (without
460 * recursing). Sort dir if necessary. subdirname must be a directory
461 * name (i.e., end in '/'). If mkdir is set, then create the
462 * directory if it is missing; otherwise, return NULL if the desired
463 * directory cannot be found. dir must already be complete.
464 */
465 static struct ref_dir *search_for_subdir(struct ref_dir *dir,
466 const char *subdirname, size_t len,
467 int mkdir)
468 {
469 int entry_index = search_ref_dir(dir, subdirname, len);
470 struct ref_entry *entry;
471 if (entry_index == -1) {
472 if (!mkdir)
473 return NULL;
474 /*
475 * Since dir is complete, the absence of a subdir
476 * means that the subdir really doesn't exist;
477 * therefore, create an empty record for it but mark
478 * the record complete.
479 */
480 entry = create_dir_entry(dir->ref_cache, subdirname, len, 0);
481 add_entry_to_dir(dir, entry);
482 } else {
483 entry = dir->entries[entry_index];
484 }
485 return get_ref_dir(entry);
486 }
487
488 /*
489 * If refname is a reference name, find the ref_dir within the dir
490 * tree that should hold refname. If refname is a directory name
491 * (i.e., ends in '/'), then return that ref_dir itself. dir must
492 * represent the top-level directory and must already be complete.
493 * Sort ref_dirs and recurse into subdirectories as necessary. If
494 * mkdir is set, then create any missing directories; otherwise,
495 * return NULL if the desired directory cannot be found.
496 */
497 static struct ref_dir *find_containing_dir(struct ref_dir *dir,
498 const char *refname, int mkdir)
499 {
500 const char *slash;
501 for (slash = strchr(refname, '/'); slash; slash = strchr(slash + 1, '/')) {
502 size_t dirnamelen = slash - refname + 1;
503 struct ref_dir *subdir;
504 subdir = search_for_subdir(dir, refname, dirnamelen, mkdir);
505 if (!subdir) {
506 dir = NULL;
507 break;
508 }
509 dir = subdir;
510 }
511
512 return dir;
513 }
514
515 /*
516 * Find the value entry with the given name in dir, sorting ref_dirs
517 * and recursing into subdirectories as necessary. If the name is not
518 * found or it corresponds to a directory entry, return NULL.
519 */
520 static struct ref_entry *find_ref(struct ref_dir *dir, const char *refname)
521 {
522 int entry_index;
523 struct ref_entry *entry;
524 dir = find_containing_dir(dir, refname, 0);
525 if (!dir)
526 return NULL;
527 entry_index = search_ref_dir(dir, refname, strlen(refname));
528 if (entry_index == -1)
529 return NULL;
530 entry = dir->entries[entry_index];
531 return (entry->flag & REF_DIR) ? NULL : entry;
532 }
533
534 /*
535 * Remove the entry with the given name from dir, recursing into
536 * subdirectories as necessary. If refname is the name of a directory
537 * (i.e., ends with '/'), then remove the directory and its contents.
538 * If the removal was successful, return the number of entries
539 * remaining in the directory entry that contained the deleted entry.
540 * If the name was not found, return -1. Please note that this
541 * function only deletes the entry from the cache; it does not delete
542 * it from the filesystem or ensure that other cache entries (which
543 * might be symbolic references to the removed entry) are updated.
544 * Nor does it remove any containing dir entries that might be made
545 * empty by the removal. dir must represent the top-level directory
546 * and must already be complete.
547 */
548 static int remove_entry(struct ref_dir *dir, const char *refname)
549 {
550 int refname_len = strlen(refname);
551 int entry_index;
552 struct ref_entry *entry;
553 int is_dir = refname[refname_len - 1] == '/';
554 if (is_dir) {
555 /*
556 * refname represents a reference directory. Remove
557 * the trailing slash; otherwise we will get the
558 * directory *representing* refname rather than the
559 * one *containing* it.
560 */
561 char *dirname = xmemdupz(refname, refname_len - 1);
562 dir = find_containing_dir(dir, dirname, 0);
563 free(dirname);
564 } else {
565 dir = find_containing_dir(dir, refname, 0);
566 }
567 if (!dir)
568 return -1;
569 entry_index = search_ref_dir(dir, refname, refname_len);
570 if (entry_index == -1)
571 return -1;
572 entry = dir->entries[entry_index];
573
574 memmove(&dir->entries[entry_index],
575 &dir->entries[entry_index + 1],
576 (dir->nr - entry_index - 1) * sizeof(*dir->entries)
577 );
578 dir->nr--;
579 if (dir->sorted > entry_index)
580 dir->sorted--;
581 free_ref_entry(entry);
582 return dir->nr;
583 }
584
585 /*
586 * Add a ref_entry to the ref_dir (unsorted), recursing into
587 * subdirectories as necessary. dir must represent the top-level
588 * directory. Return 0 on success.
589 */
590 static int add_ref(struct ref_dir *dir, struct ref_entry *ref)
591 {
592 dir = find_containing_dir(dir, ref->name, 1);
593 if (!dir)
594 return -1;
595 add_entry_to_dir(dir, ref);
596 return 0;
597 }
598
599 /*
600 * Emit a warning and return true iff ref1 and ref2 have the same name
601 * and the same sha1. Die if they have the same name but different
602 * sha1s.
603 */
604 static int is_dup_ref(const struct ref_entry *ref1, const struct ref_entry *ref2)
605 {
606 if (strcmp(ref1->name, ref2->name))
607 return 0;
608
609 /* Duplicate name; make sure that they don't conflict: */
610
611 if ((ref1->flag & REF_DIR) || (ref2->flag & REF_DIR))
612 /* This is impossible by construction */
613 die("Reference directory conflict: %s", ref1->name);
614
615 if (hashcmp(ref1->u.value.sha1, ref2->u.value.sha1))
616 die("Duplicated ref, and SHA1s don't match: %s", ref1->name);
617
618 warning("Duplicated ref: %s", ref1->name);
619 return 1;
620 }
621
622 /*
623 * Sort the entries in dir non-recursively (if they are not already
624 * sorted) and remove any duplicate entries.
625 */
626 static void sort_ref_dir(struct ref_dir *dir)
627 {
628 int i, j;
629 struct ref_entry *last = NULL;
630
631 /*
632 * This check also prevents passing a zero-length array to qsort(),
633 * which is a problem on some platforms.
634 */
635 if (dir->sorted == dir->nr)
636 return;
637
638 qsort(dir->entries, dir->nr, sizeof(*dir->entries), ref_entry_cmp);
639
640 /* Remove any duplicates: */
641 for (i = 0, j = 0; j < dir->nr; j++) {
642 struct ref_entry *entry = dir->entries[j];
643 if (last && is_dup_ref(last, entry))
644 free_ref_entry(entry);
645 else
646 last = dir->entries[i++] = entry;
647 }
648 dir->sorted = dir->nr = i;
649 }
650
651 /* Include broken references in a do_for_each_ref*() iteration: */
652 #define DO_FOR_EACH_INCLUDE_BROKEN 0x01
653
654 /*
655 * Return true iff the reference described by entry can be resolved to
656 * an object in the database. Emit a warning if the referred-to
657 * object does not exist.
658 */
659 static int ref_resolves_to_object(struct ref_entry *entry)
660 {
661 if (entry->flag & REF_ISBROKEN)
662 return 0;
663 if (!has_sha1_file(entry->u.value.sha1)) {
664 error("%s does not point to a valid object!", entry->name);
665 return 0;
666 }
667 return 1;
668 }
669
670 /*
671 * current_ref is a performance hack: when iterating over references
672 * using the for_each_ref*() functions, current_ref is set to the
673 * current reference's entry before calling the callback function. If
674 * the callback function calls peel_ref(), then peel_ref() first
675 * checks whether the reference to be peeled is the current reference
676 * (it usually is) and if so, returns that reference's peeled version
677 * if it is available. This avoids a refname lookup in a common case.
678 */
679 static struct ref_entry *current_ref;
680
681 typedef int each_ref_entry_fn(struct ref_entry *entry, void *cb_data);
682
683 struct ref_entry_cb {
684 const char *base;
685 int trim;
686 int flags;
687 each_ref_fn *fn;
688 void *cb_data;
689 };
690
691 /*
692 * Handle one reference in a do_for_each_ref*()-style iteration,
693 * calling an each_ref_fn for each entry.
694 */
695 static int do_one_ref(struct ref_entry *entry, void *cb_data)
696 {
697 struct ref_entry_cb *data = cb_data;
698 struct ref_entry *old_current_ref;
699 int retval;
700
701 if (!starts_with(entry->name, data->base))
702 return 0;
703
704 if (!(data->flags & DO_FOR_EACH_INCLUDE_BROKEN) &&
705 !ref_resolves_to_object(entry))
706 return 0;
707
708 /* Store the old value, in case this is a recursive call: */
709 old_current_ref = current_ref;
710 current_ref = entry;
711 retval = data->fn(entry->name + data->trim, entry->u.value.sha1,
712 entry->flag, data->cb_data);
713 current_ref = old_current_ref;
714 return retval;
715 }
716
717 /*
718 * Call fn for each reference in dir that has index in the range
719 * offset <= index < dir->nr. Recurse into subdirectories that are in
720 * that index range, sorting them before iterating. This function
721 * does not sort dir itself; it should be sorted beforehand. fn is
722 * called for all references, including broken ones.
723 */
724 static int do_for_each_entry_in_dir(struct ref_dir *dir, int offset,
725 each_ref_entry_fn fn, void *cb_data)
726 {
727 int i;
728 assert(dir->sorted == dir->nr);
729 for (i = offset; i < dir->nr; i++) {
730 struct ref_entry *entry = dir->entries[i];
731 int retval;
732 if (entry->flag & REF_DIR) {
733 struct ref_dir *subdir = get_ref_dir(entry);
734 sort_ref_dir(subdir);
735 retval = do_for_each_entry_in_dir(subdir, 0, fn, cb_data);
736 } else {
737 retval = fn(entry, cb_data);
738 }
739 if (retval)
740 return retval;
741 }
742 return 0;
743 }
744
745 /*
746 * Call fn for each reference in the union of dir1 and dir2, in order
747 * by refname. Recurse into subdirectories. If a value entry appears
748 * in both dir1 and dir2, then only process the version that is in
749 * dir2. The input dirs must already be sorted, but subdirs will be
750 * sorted as needed. fn is called for all references, including
751 * broken ones.
752 */
753 static int do_for_each_entry_in_dirs(struct ref_dir *dir1,
754 struct ref_dir *dir2,
755 each_ref_entry_fn fn, void *cb_data)
756 {
757 int retval;
758 int i1 = 0, i2 = 0;
759
760 assert(dir1->sorted == dir1->nr);
761 assert(dir2->sorted == dir2->nr);
762 while (1) {
763 struct ref_entry *e1, *e2;
764 int cmp;
765 if (i1 == dir1->nr) {
766 return do_for_each_entry_in_dir(dir2, i2, fn, cb_data);
767 }
768 if (i2 == dir2->nr) {
769 return do_for_each_entry_in_dir(dir1, i1, fn, cb_data);
770 }
771 e1 = dir1->entries[i1];
772 e2 = dir2->entries[i2];
773 cmp = strcmp(e1->name, e2->name);
774 if (cmp == 0) {
775 if ((e1->flag & REF_DIR) && (e2->flag & REF_DIR)) {
776 /* Both are directories; descend them in parallel. */
777 struct ref_dir *subdir1 = get_ref_dir(e1);
778 struct ref_dir *subdir2 = get_ref_dir(e2);
779 sort_ref_dir(subdir1);
780 sort_ref_dir(subdir2);
781 retval = do_for_each_entry_in_dirs(
782 subdir1, subdir2, fn, cb_data);
783 i1++;
784 i2++;
785 } else if (!(e1->flag & REF_DIR) && !(e2->flag & REF_DIR)) {
786 /* Both are references; ignore the one from dir1. */
787 retval = fn(e2, cb_data);
788 i1++;
789 i2++;
790 } else {
791 die("conflict between reference and directory: %s",
792 e1->name);
793 }
794 } else {
795 struct ref_entry *e;
796 if (cmp < 0) {
797 e = e1;
798 i1++;
799 } else {
800 e = e2;
801 i2++;
802 }
803 if (e->flag & REF_DIR) {
804 struct ref_dir *subdir = get_ref_dir(e);
805 sort_ref_dir(subdir);
806 retval = do_for_each_entry_in_dir(
807 subdir, 0, fn, cb_data);
808 } else {
809 retval = fn(e, cb_data);
810 }
811 }
812 if (retval)
813 return retval;
814 }
815 }
816
817 /*
818 * Load all of the refs from the dir into our in-memory cache. The hard work
819 * of loading loose refs is done by get_ref_dir(), so we just need to recurse
820 * through all of the sub-directories. We do not even need to care about
821 * sorting, as traversal order does not matter to us.
822 */
823 static void prime_ref_dir(struct ref_dir *dir)
824 {
825 int i;
826 for (i = 0; i < dir->nr; i++) {
827 struct ref_entry *entry = dir->entries[i];
828 if (entry->flag & REF_DIR)
829 prime_ref_dir(get_ref_dir(entry));
830 }
831 }
832
833 static int entry_matches(struct ref_entry *entry, const struct string_list *list)
834 {
835 return list && string_list_has_string(list, entry->name);
836 }
837
838 struct nonmatching_ref_data {
839 const struct string_list *skip;
840 struct ref_entry *found;
841 };
842
843 static int nonmatching_ref_fn(struct ref_entry *entry, void *vdata)
844 {
845 struct nonmatching_ref_data *data = vdata;
846
847 if (entry_matches(entry, data->skip))
848 return 0;
849
850 data->found = entry;
851 return 1;
852 }
853
854 static void report_refname_conflict(struct ref_entry *entry,
855 const char *refname)
856 {
857 error("'%s' exists; cannot create '%s'", entry->name, refname);
858 }
859
860 /*
861 * Return true iff a reference named refname could be created without
862 * conflicting with the name of an existing reference in dir. If
863 * skip is non-NULL, ignore potential conflicts with refs in skip
864 * (e.g., because they are scheduled for deletion in the same
865 * operation).
866 *
867 * Two reference names conflict if one of them exactly matches the
868 * leading components of the other; e.g., "foo/bar" conflicts with
869 * both "foo" and with "foo/bar/baz" but not with "foo/bar" or
870 * "foo/barbados".
871 *
872 * skip must be sorted.
873 */
874 static int is_refname_available(const char *refname,
875 const struct string_list *skip,
876 struct ref_dir *dir)
877 {
878 const char *slash;
879 size_t len;
880 int pos;
881 char *dirname;
882
883 for (slash = strchr(refname, '/'); slash; slash = strchr(slash + 1, '/')) {
884 /*
885 * We are still at a leading dir of the refname; we are
886 * looking for a conflict with a leaf entry.
887 *
888 * If we find one, we still must make sure it is
889 * not in "skip".
890 */
891 pos = search_ref_dir(dir, refname, slash - refname);
892 if (pos >= 0) {
893 struct ref_entry *entry = dir->entries[pos];
894 if (entry_matches(entry, skip))
895 return 1;
896 report_refname_conflict(entry, refname);
897 return 0;
898 }
899
900
901 /*
902 * Otherwise, we can try to continue our search with
903 * the next component; if we come up empty, we know
904 * there is nothing under this whole prefix.
905 */
906 pos = search_ref_dir(dir, refname, slash + 1 - refname);
907 if (pos < 0)
908 return 1;
909
910 dir = get_ref_dir(dir->entries[pos]);
911 }
912
913 /*
914 * We are at the leaf of our refname; we want to
915 * make sure there are no directories which match it.
916 */
917 len = strlen(refname);
918 dirname = xmallocz(len + 1);
919 sprintf(dirname, "%s/", refname);
920 pos = search_ref_dir(dir, dirname, len + 1);
921 free(dirname);
922
923 if (pos >= 0) {
924 /*
925 * We found a directory named "refname". It is a
926 * problem iff it contains any ref that is not
927 * in "skip".
928 */
929 struct ref_entry *entry = dir->entries[pos];
930 struct ref_dir *dir = get_ref_dir(entry);
931 struct nonmatching_ref_data data;
932
933 data.skip = skip;
934 sort_ref_dir(dir);
935 if (!do_for_each_entry_in_dir(dir, 0, nonmatching_ref_fn, &data))
936 return 1;
937
938 report_refname_conflict(data.found, refname);
939 return 0;
940 }
941
942 /*
943 * There is no point in searching for another leaf
944 * node which matches it; such an entry would be the
945 * ref we are looking for, not a conflict.
946 */
947 return 1;
948 }
949
950 struct packed_ref_cache {
951 struct ref_entry *root;
952
953 /*
954 * Count of references to the data structure in this instance,
955 * including the pointer from ref_cache::packed if any. The
956 * data will not be freed as long as the reference count is
957 * nonzero.
958 */
959 unsigned int referrers;
960
961 /*
962 * Iff the packed-refs file associated with this instance is
963 * currently locked for writing, this points at the associated
964 * lock (which is owned by somebody else). The referrer count
965 * is also incremented when the file is locked and decremented
966 * when it is unlocked.
967 */
968 struct lock_file *lock;
969
970 /* The metadata from when this packed-refs cache was read */
971 struct stat_validity validity;
972 };
973
974 /*
975 * Future: need to be in "struct repository"
976 * when doing a full libification.
977 */
978 static struct ref_cache {
979 struct ref_cache *next;
980 struct ref_entry *loose;
981 struct packed_ref_cache *packed;
982 /*
983 * The submodule name, or "" for the main repo. We allocate
984 * length 1 rather than FLEX_ARRAY so that the main ref_cache
985 * is initialized correctly.
986 */
987 char name[1];
988 } ref_cache, *submodule_ref_caches;
989
990 /* Lock used for the main packed-refs file: */
991 static struct lock_file packlock;
992
993 /*
994 * Increment the reference count of *packed_refs.
995 */
996 static void acquire_packed_ref_cache(struct packed_ref_cache *packed_refs)
997 {
998 packed_refs->referrers++;
999 }
1000
1001 /*
1002 * Decrease the reference count of *packed_refs. If it goes to zero,
1003 * free *packed_refs and return true; otherwise return false.
1004 */
1005 static int release_packed_ref_cache(struct packed_ref_cache *packed_refs)
1006 {
1007 if (!--packed_refs->referrers) {
1008 free_ref_entry(packed_refs->root);
1009 stat_validity_clear(&packed_refs->validity);
1010 free(packed_refs);
1011 return 1;
1012 } else {
1013 return 0;
1014 }
1015 }
1016
1017 static void clear_packed_ref_cache(struct ref_cache *refs)
1018 {
1019 if (refs->packed) {
1020 struct packed_ref_cache *packed_refs = refs->packed;
1021
1022 if (packed_refs->lock)
1023 die("internal error: packed-ref cache cleared while locked");
1024 refs->packed = NULL;
1025 release_packed_ref_cache(packed_refs);
1026 }
1027 }
1028
1029 static void clear_loose_ref_cache(struct ref_cache *refs)
1030 {
1031 if (refs->loose) {
1032 free_ref_entry(refs->loose);
1033 refs->loose = NULL;
1034 }
1035 }
1036
1037 static struct ref_cache *create_ref_cache(const char *submodule)
1038 {
1039 int len;
1040 struct ref_cache *refs;
1041 if (!submodule)
1042 submodule = "";
1043 len = strlen(submodule) + 1;
1044 refs = xcalloc(1, sizeof(struct ref_cache) + len);
1045 memcpy(refs->name, submodule, len);
1046 return refs;
1047 }
1048
1049 /*
1050 * Return a pointer to a ref_cache for the specified submodule. For
1051 * the main repository, use submodule==NULL. The returned structure
1052 * will be allocated and initialized but not necessarily populated; it
1053 * should not be freed.
1054 */
1055 static struct ref_cache *get_ref_cache(const char *submodule)
1056 {
1057 struct ref_cache *refs;
1058
1059 if (!submodule || !*submodule)
1060 return &ref_cache;
1061
1062 for (refs = submodule_ref_caches; refs; refs = refs->next)
1063 if (!strcmp(submodule, refs->name))
1064 return refs;
1065
1066 refs = create_ref_cache(submodule);
1067 refs->next = submodule_ref_caches;
1068 submodule_ref_caches = refs;
1069 return refs;
1070 }
1071
1072 /* The length of a peeled reference line in packed-refs, including EOL: */
1073 #define PEELED_LINE_LENGTH 42
1074
1075 /*
1076 * The packed-refs header line that we write out. Perhaps other
1077 * traits will be added later. The trailing space is required.
1078 */
1079 static const char PACKED_REFS_HEADER[] =
1080 "# pack-refs with: peeled fully-peeled \n";
1081
1082 /*
1083 * Parse one line from a packed-refs file. Write the SHA1 to sha1.
1084 * Return a pointer to the refname within the line (null-terminated),
1085 * or NULL if there was a problem.
1086 */
1087 static const char *parse_ref_line(struct strbuf *line, unsigned char *sha1)
1088 {
1089 const char *ref;
1090
1091 /*
1092 * 42: the answer to everything.
1093 *
1094 * In this case, it happens to be the answer to
1095 * 40 (length of sha1 hex representation)
1096 * +1 (space in between hex and name)
1097 * +1 (newline at the end of the line)
1098 */
1099 if (line->len <= 42)
1100 return NULL;
1101
1102 if (get_sha1_hex(line->buf, sha1) < 0)
1103 return NULL;
1104 if (!isspace(line->buf[40]))
1105 return NULL;
1106
1107 ref = line->buf + 41;
1108 if (isspace(*ref))
1109 return NULL;
1110
1111 if (line->buf[line->len - 1] != '\n')
1112 return NULL;
1113 line->buf[--line->len] = 0;
1114
1115 return ref;
1116 }
1117
1118 /*
1119 * Read f, which is a packed-refs file, into dir.
1120 *
1121 * A comment line of the form "# pack-refs with: " may contain zero or
1122 * more traits. We interpret the traits as follows:
1123 *
1124 * No traits:
1125 *
1126 * Probably no references are peeled. But if the file contains a
1127 * peeled value for a reference, we will use it.
1128 *
1129 * peeled:
1130 *
1131 * References under "refs/tags/", if they *can* be peeled, *are*
1132 * peeled in this file. References outside of "refs/tags/" are
1133 * probably not peeled even if they could have been, but if we find
1134 * a peeled value for such a reference we will use it.
1135 *
1136 * fully-peeled:
1137 *
1138 * All references in the file that can be peeled are peeled.
1139 * Inversely (and this is more important), any references in the
1140 * file for which no peeled value is recorded is not peelable. This
1141 * trait should typically be written alongside "peeled" for
1142 * compatibility with older clients, but we do not require it
1143 * (i.e., "peeled" is a no-op if "fully-peeled" is set).
1144 */
1145 static void read_packed_refs(FILE *f, struct ref_dir *dir)
1146 {
1147 struct ref_entry *last = NULL;
1148 struct strbuf line = STRBUF_INIT;
1149 enum { PEELED_NONE, PEELED_TAGS, PEELED_FULLY } peeled = PEELED_NONE;
1150
1151 while (strbuf_getwholeline(&line, f, '\n') != EOF) {
1152 unsigned char sha1[20];
1153 const char *refname;
1154 const char *traits;
1155
1156 if (skip_prefix(line.buf, "# pack-refs with:", &traits)) {
1157 if (strstr(traits, " fully-peeled "))
1158 peeled = PEELED_FULLY;
1159 else if (strstr(traits, " peeled "))
1160 peeled = PEELED_TAGS;
1161 /* perhaps other traits later as well */
1162 continue;
1163 }
1164
1165 refname = parse_ref_line(&line, sha1);
1166 if (refname) {
1167 int flag = REF_ISPACKED;
1168
1169 if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
1170 hashclr(sha1);
1171 flag |= REF_BAD_NAME | REF_ISBROKEN;
1172 }
1173 last = create_ref_entry(refname, sha1, flag, 0);
1174 if (peeled == PEELED_FULLY ||
1175 (peeled == PEELED_TAGS && starts_with(refname, "refs/tags/")))
1176 last->flag |= REF_KNOWS_PEELED;
1177 add_ref(dir, last);
1178 continue;
1179 }
1180 if (last &&
1181 line.buf[0] == '^' &&
1182 line.len == PEELED_LINE_LENGTH &&
1183 line.buf[PEELED_LINE_LENGTH - 1] == '\n' &&
1184 !get_sha1_hex(line.buf + 1, sha1)) {
1185 hashcpy(last->u.value.peeled, sha1);
1186 /*
1187 * Regardless of what the file header said,
1188 * we definitely know the value of *this*
1189 * reference:
1190 */
1191 last->flag |= REF_KNOWS_PEELED;
1192 }
1193 }
1194
1195 strbuf_release(&line);
1196 }
1197
1198 /*
1199 * Get the packed_ref_cache for the specified ref_cache, creating it
1200 * if necessary.
1201 */
1202 static struct packed_ref_cache *get_packed_ref_cache(struct ref_cache *refs)
1203 {
1204 const char *packed_refs_file;
1205
1206 if (*refs->name)
1207 packed_refs_file = git_path_submodule(refs->name, "packed-refs");
1208 else
1209 packed_refs_file = git_path("packed-refs");
1210
1211 if (refs->packed &&
1212 !stat_validity_check(&refs->packed->validity, packed_refs_file))
1213 clear_packed_ref_cache(refs);
1214
1215 if (!refs->packed) {
1216 FILE *f;
1217
1218 refs->packed = xcalloc(1, sizeof(*refs->packed));
1219 acquire_packed_ref_cache(refs->packed);
1220 refs->packed->root = create_dir_entry(refs, "", 0, 0);
1221 f = fopen(packed_refs_file, "r");
1222 if (f) {
1223 stat_validity_update(&refs->packed->validity, fileno(f));
1224 read_packed_refs(f, get_ref_dir(refs->packed->root));
1225 fclose(f);
1226 }
1227 }
1228 return refs->packed;
1229 }
1230
1231 static struct ref_dir *get_packed_ref_dir(struct packed_ref_cache *packed_ref_cache)
1232 {
1233 return get_ref_dir(packed_ref_cache->root);
1234 }
1235
1236 static struct ref_dir *get_packed_refs(struct ref_cache *refs)
1237 {
1238 return get_packed_ref_dir(get_packed_ref_cache(refs));
1239 }
1240
1241 void add_packed_ref(const char *refname, const unsigned char *sha1)
1242 {
1243 struct packed_ref_cache *packed_ref_cache =
1244 get_packed_ref_cache(&ref_cache);
1245
1246 if (!packed_ref_cache->lock)
1247 die("internal error: packed refs not locked");
1248 add_ref(get_packed_ref_dir(packed_ref_cache),
1249 create_ref_entry(refname, sha1, REF_ISPACKED, 1));
1250 }
1251
1252 /*
1253 * Read the loose references from the namespace dirname into dir
1254 * (without recursing). dirname must end with '/'. dir must be the
1255 * directory entry corresponding to dirname.
1256 */
1257 static void read_loose_refs(const char *dirname, struct ref_dir *dir)
1258 {
1259 struct ref_cache *refs = dir->ref_cache;
1260 DIR *d;
1261 const char *path;
1262 struct dirent *de;
1263 int dirnamelen = strlen(dirname);
1264 struct strbuf refname;
1265
1266 if (*refs->name)
1267 path = git_path_submodule(refs->name, "%s", dirname);
1268 else
1269 path = git_path("%s", dirname);
1270
1271 d = opendir(path);
1272 if (!d)
1273 return;
1274
1275 strbuf_init(&refname, dirnamelen + 257);
1276 strbuf_add(&refname, dirname, dirnamelen);
1277
1278 while ((de = readdir(d)) != NULL) {
1279 unsigned char sha1[20];
1280 struct stat st;
1281 int flag;
1282 const char *refdir;
1283
1284 if (de->d_name[0] == '.')
1285 continue;
1286 if (ends_with(de->d_name, ".lock"))
1287 continue;
1288 strbuf_addstr(&refname, de->d_name);
1289 refdir = *refs->name
1290 ? git_path_submodule(refs->name, "%s", refname.buf)
1291 : git_path("%s", refname.buf);
1292 if (stat(refdir, &st) < 0) {
1293 ; /* silently ignore */
1294 } else if (S_ISDIR(st.st_mode)) {
1295 strbuf_addch(&refname, '/');
1296 add_entry_to_dir(dir,
1297 create_dir_entry(refs, refname.buf,
1298 refname.len, 1));
1299 } else {
1300 if (*refs->name) {
1301 hashclr(sha1);
1302 flag = 0;
1303 if (resolve_gitlink_ref(refs->name, refname.buf, sha1) < 0) {
1304 hashclr(sha1);
1305 flag |= REF_ISBROKEN;
1306 }
1307 } else if (read_ref_full(refname.buf,
1308 RESOLVE_REF_READING,
1309 sha1, &flag)) {
1310 hashclr(sha1);
1311 flag |= REF_ISBROKEN;
1312 }
1313 if (check_refname_format(refname.buf,
1314 REFNAME_ALLOW_ONELEVEL)) {
1315 hashclr(sha1);
1316 flag |= REF_BAD_NAME | REF_ISBROKEN;
1317 }
1318 add_entry_to_dir(dir,
1319 create_ref_entry(refname.buf, sha1, flag, 0));
1320 }
1321 strbuf_setlen(&refname, dirnamelen);
1322 }
1323 strbuf_release(&refname);
1324 closedir(d);
1325 }
1326
1327 static struct ref_dir *get_loose_refs(struct ref_cache *refs)
1328 {
1329 if (!refs->loose) {
1330 /*
1331 * Mark the top-level directory complete because we
1332 * are about to read the only subdirectory that can
1333 * hold references:
1334 */
1335 refs->loose = create_dir_entry(refs, "", 0, 0);
1336 /*
1337 * Create an incomplete entry for "refs/":
1338 */
1339 add_entry_to_dir(get_ref_dir(refs->loose),
1340 create_dir_entry(refs, "refs/", 5, 1));
1341 }
1342 return get_ref_dir(refs->loose);
1343 }
1344
1345 /* We allow "recursive" symbolic refs. Only within reason, though */
1346 #define MAXDEPTH 5
1347 #define MAXREFLEN (1024)
1348
1349 /*
1350 * Called by resolve_gitlink_ref_recursive() after it failed to read
1351 * from the loose refs in ref_cache refs. Find <refname> in the
1352 * packed-refs file for the submodule.
1353 */
1354 static int resolve_gitlink_packed_ref(struct ref_cache *refs,
1355 const char *refname, unsigned char *sha1)
1356 {
1357 struct ref_entry *ref;
1358 struct ref_dir *dir = get_packed_refs(refs);
1359
1360 ref = find_ref(dir, refname);
1361 if (ref == NULL)
1362 return -1;
1363
1364 hashcpy(sha1, ref->u.value.sha1);
1365 return 0;
1366 }
1367
1368 static int resolve_gitlink_ref_recursive(struct ref_cache *refs,
1369 const char *refname, unsigned char *sha1,
1370 int recursion)
1371 {
1372 int fd, len;
1373 char buffer[128], *p;
1374 char *path;
1375
1376 if (recursion > MAXDEPTH || strlen(refname) > MAXREFLEN)
1377 return -1;
1378 path = *refs->name
1379 ? git_path_submodule(refs->name, "%s", refname)
1380 : git_path("%s", refname);
1381 fd = open(path, O_RDONLY);
1382 if (fd < 0)
1383 return resolve_gitlink_packed_ref(refs, refname, sha1);
1384
1385 len = read(fd, buffer, sizeof(buffer)-1);
1386 close(fd);
1387 if (len < 0)
1388 return -1;
1389 while (len && isspace(buffer[len-1]))
1390 len--;
1391 buffer[len] = 0;
1392
1393 /* Was it a detached head or an old-fashioned symlink? */
1394 if (!get_sha1_hex(buffer, sha1))
1395 return 0;
1396
1397 /* Symref? */
1398 if (strncmp(buffer, "ref:", 4))
1399 return -1;
1400 p = buffer + 4;
1401 while (isspace(*p))
1402 p++;
1403
1404 return resolve_gitlink_ref_recursive(refs, p, sha1, recursion+1);
1405 }
1406
1407 int resolve_gitlink_ref(const char *path, const char *refname, unsigned char *sha1)
1408 {
1409 int len = strlen(path), retval;
1410 char *submodule;
1411 struct ref_cache *refs;
1412
1413 while (len && path[len-1] == '/')
1414 len--;
1415 if (!len)
1416 return -1;
1417 submodule = xstrndup(path, len);
1418 refs = get_ref_cache(submodule);
1419 free(submodule);
1420
1421 retval = resolve_gitlink_ref_recursive(refs, refname, sha1, 0);
1422 return retval;
1423 }
1424
1425 /*
1426 * Return the ref_entry for the given refname from the packed
1427 * references. If it does not exist, return NULL.
1428 */
1429 static struct ref_entry *get_packed_ref(const char *refname)
1430 {
1431 return find_ref(get_packed_refs(&ref_cache), refname);
1432 }
1433
1434 /*
1435 * A loose ref file doesn't exist; check for a packed ref. The
1436 * options are forwarded from resolve_safe_unsafe().
1437 */
1438 static int resolve_missing_loose_ref(const char *refname,
1439 int resolve_flags,
1440 unsigned char *sha1,
1441 int *flags)
1442 {
1443 struct ref_entry *entry;
1444
1445 /*
1446 * The loose reference file does not exist; check for a packed
1447 * reference.
1448 */
1449 entry = get_packed_ref(refname);
1450 if (entry) {
1451 hashcpy(sha1, entry->u.value.sha1);
1452 if (flags)
1453 *flags |= REF_ISPACKED;
1454 return 0;
1455 }
1456 /* The reference is not a packed reference, either. */
1457 if (resolve_flags & RESOLVE_REF_READING) {
1458 errno = ENOENT;
1459 return -1;
1460 } else {
1461 hashclr(sha1);
1462 return 0;
1463 }
1464 }
1465
1466 /* This function needs to return a meaningful errno on failure */
1467 const char *resolve_ref_unsafe(const char *refname, int resolve_flags, unsigned char *sha1, int *flags)
1468 {
1469 int depth = MAXDEPTH;
1470 ssize_t len;
1471 char buffer[256];
1472 static char refname_buffer[256];
1473 int bad_name = 0;
1474
1475 if (flags)
1476 *flags = 0;
1477
1478 if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
1479 if (flags)
1480 *flags |= REF_BAD_NAME;
1481
1482 if (!(resolve_flags & RESOLVE_REF_ALLOW_BAD_NAME) ||
1483 !refname_is_safe(refname)) {
1484 errno = EINVAL;
1485 return NULL;
1486 }
1487 /*
1488 * dwim_ref() uses REF_ISBROKEN to distinguish between
1489 * missing refs and refs that were present but invalid,
1490 * to complain about the latter to stderr.
1491 *
1492 * We don't know whether the ref exists, so don't set
1493 * REF_ISBROKEN yet.
1494 */
1495 bad_name = 1;
1496 }
1497 for (;;) {
1498 char path[PATH_MAX];
1499 struct stat st;
1500 char *buf;
1501 int fd;
1502
1503 if (--depth < 0) {
1504 errno = ELOOP;
1505 return NULL;
1506 }
1507
1508 git_snpath(path, sizeof(path), "%s", refname);
1509
1510 /*
1511 * We might have to loop back here to avoid a race
1512 * condition: first we lstat() the file, then we try
1513 * to read it as a link or as a file. But if somebody
1514 * changes the type of the file (file <-> directory
1515 * <-> symlink) between the lstat() and reading, then
1516 * we don't want to report that as an error but rather
1517 * try again starting with the lstat().
1518 */
1519 stat_ref:
1520 if (lstat(path, &st) < 0) {
1521 if (errno != ENOENT)
1522 return NULL;
1523 if (resolve_missing_loose_ref(refname, resolve_flags,
1524 sha1, flags))
1525 return NULL;
1526 if (bad_name) {
1527 hashclr(sha1);
1528 if (flags)
1529 *flags |= REF_ISBROKEN;
1530 }
1531 return refname;
1532 }
1533
1534 /* Follow "normalized" - ie "refs/.." symlinks by hand */
1535 if (S_ISLNK(st.st_mode)) {
1536 len = readlink(path, buffer, sizeof(buffer)-1);
1537 if (len < 0) {
1538 if (errno == ENOENT || errno == EINVAL)
1539 /* inconsistent with lstat; retry */
1540 goto stat_ref;
1541 else
1542 return NULL;
1543 }
1544 buffer[len] = 0;
1545 if (starts_with(buffer, "refs/") &&
1546 !check_refname_format(buffer, 0)) {
1547 strcpy(refname_buffer, buffer);
1548 refname = refname_buffer;
1549 if (flags)
1550 *flags |= REF_ISSYMREF;
1551 if (resolve_flags & RESOLVE_REF_NO_RECURSE) {
1552 hashclr(sha1);
1553 return refname;
1554 }
1555 continue;
1556 }
1557 }
1558
1559 /* Is it a directory? */
1560 if (S_ISDIR(st.st_mode)) {
1561 errno = EISDIR;
1562 return NULL;
1563 }
1564
1565 /*
1566 * Anything else, just open it and try to use it as
1567 * a ref
1568 */
1569 fd = open(path, O_RDONLY);
1570 if (fd < 0) {
1571 if (errno == ENOENT)
1572 /* inconsistent with lstat; retry */
1573 goto stat_ref;
1574 else
1575 return NULL;
1576 }
1577 len = read_in_full(fd, buffer, sizeof(buffer)-1);
1578 if (len < 0) {
1579 int save_errno = errno;
1580 close(fd);
1581 errno = save_errno;
1582 return NULL;
1583 }
1584 close(fd);
1585 while (len && isspace(buffer[len-1]))
1586 len--;
1587 buffer[len] = '\0';
1588
1589 /*
1590 * Is it a symbolic ref?
1591 */
1592 if (!starts_with(buffer, "ref:")) {
1593 /*
1594 * Please note that FETCH_HEAD has a second
1595 * line containing other data.
1596 */
1597 if (get_sha1_hex(buffer, sha1) ||
1598 (buffer[40] != '\0' && !isspace(buffer[40]))) {
1599 if (flags)
1600 *flags |= REF_ISBROKEN;
1601 errno = EINVAL;
1602 return NULL;
1603 }
1604 if (bad_name) {
1605 hashclr(sha1);
1606 if (flags)
1607 *flags |= REF_ISBROKEN;
1608 }
1609 return refname;
1610 }
1611 if (flags)
1612 *flags |= REF_ISSYMREF;
1613 buf = buffer + 4;
1614 while (isspace(*buf))
1615 buf++;
1616 refname = strcpy(refname_buffer, buf);
1617 if (resolve_flags & RESOLVE_REF_NO_RECURSE) {
1618 hashclr(sha1);
1619 return refname;
1620 }
1621 if (check_refname_format(buf, REFNAME_ALLOW_ONELEVEL)) {
1622 if (flags)
1623 *flags |= REF_ISBROKEN;
1624
1625 if (!(resolve_flags & RESOLVE_REF_ALLOW_BAD_NAME) ||
1626 !refname_is_safe(buf)) {
1627 errno = EINVAL;
1628 return NULL;
1629 }
1630 bad_name = 1;
1631 }
1632 }
1633 }
1634
1635 char *resolve_refdup(const char *ref, int resolve_flags, unsigned char *sha1, int *flags)
1636 {
1637 return xstrdup_or_null(resolve_ref_unsafe(ref, resolve_flags, sha1, flags));
1638 }
1639
1640 /* The argument to filter_refs */
1641 struct ref_filter {
1642 const char *pattern;
1643 each_ref_fn *fn;
1644 void *cb_data;
1645 };
1646
1647 int read_ref_full(const char *refname, int resolve_flags, unsigned char *sha1, int *flags)
1648 {
1649 if (resolve_ref_unsafe(refname, resolve_flags, sha1, flags))
1650 return 0;
1651 return -1;
1652 }
1653
1654 int read_ref(const char *refname, unsigned char *sha1)
1655 {
1656 return read_ref_full(refname, RESOLVE_REF_READING, sha1, NULL);
1657 }
1658
1659 int ref_exists(const char *refname)
1660 {
1661 unsigned char sha1[20];
1662 return !!resolve_ref_unsafe(refname, RESOLVE_REF_READING, sha1, NULL);
1663 }
1664
1665 static int filter_refs(const char *refname, const unsigned char *sha1, int flags,
1666 void *data)
1667 {
1668 struct ref_filter *filter = (struct ref_filter *)data;
1669 if (wildmatch(filter->pattern, refname, 0, NULL))
1670 return 0;
1671 return filter->fn(refname, sha1, flags, filter->cb_data);
1672 }
1673
1674 enum peel_status {
1675 /* object was peeled successfully: */
1676 PEEL_PEELED = 0,
1677
1678 /*
1679 * object cannot be peeled because the named object (or an
1680 * object referred to by a tag in the peel chain), does not
1681 * exist.
1682 */
1683 PEEL_INVALID = -1,
1684
1685 /* object cannot be peeled because it is not a tag: */
1686 PEEL_NON_TAG = -2,
1687
1688 /* ref_entry contains no peeled value because it is a symref: */
1689 PEEL_IS_SYMREF = -3,
1690
1691 /*
1692 * ref_entry cannot be peeled because it is broken (i.e., the
1693 * symbolic reference cannot even be resolved to an object
1694 * name):
1695 */
1696 PEEL_BROKEN = -4
1697 };
1698
1699 /*
1700 * Peel the named object; i.e., if the object is a tag, resolve the
1701 * tag recursively until a non-tag is found. If successful, store the
1702 * result to sha1 and return PEEL_PEELED. If the object is not a tag
1703 * or is not valid, return PEEL_NON_TAG or PEEL_INVALID, respectively,
1704 * and leave sha1 unchanged.
1705 */
1706 static enum peel_status peel_object(const unsigned char *name, unsigned char *sha1)
1707 {
1708 struct object *o = lookup_unknown_object(name);
1709
1710 if (o->type == OBJ_NONE) {
1711 int type = sha1_object_info(name, NULL);
1712 if (type < 0 || !object_as_type(o, type, 0))
1713 return PEEL_INVALID;
1714 }
1715
1716 if (o->type != OBJ_TAG)
1717 return PEEL_NON_TAG;
1718
1719 o = deref_tag_noverify(o);
1720 if (!o)
1721 return PEEL_INVALID;
1722
1723 hashcpy(sha1, o->sha1);
1724 return PEEL_PEELED;
1725 }
1726
1727 /*
1728 * Peel the entry (if possible) and return its new peel_status. If
1729 * repeel is true, re-peel the entry even if there is an old peeled
1730 * value that is already stored in it.
1731 *
1732 * It is OK to call this function with a packed reference entry that
1733 * might be stale and might even refer to an object that has since
1734 * been garbage-collected. In such a case, if the entry has
1735 * REF_KNOWS_PEELED then leave the status unchanged and return
1736 * PEEL_PEELED or PEEL_NON_TAG; otherwise, return PEEL_INVALID.
1737 */
1738 static enum peel_status peel_entry(struct ref_entry *entry, int repeel)
1739 {
1740 enum peel_status status;
1741
1742 if (entry->flag & REF_KNOWS_PEELED) {
1743 if (repeel) {
1744 entry->flag &= ~REF_KNOWS_PEELED;
1745 hashclr(entry->u.value.peeled);
1746 } else {
1747 return is_null_sha1(entry->u.value.peeled) ?
1748 PEEL_NON_TAG : PEEL_PEELED;
1749 }
1750 }
1751 if (entry->flag & REF_ISBROKEN)
1752 return PEEL_BROKEN;
1753 if (entry->flag & REF_ISSYMREF)
1754 return PEEL_IS_SYMREF;
1755
1756 status = peel_object(entry->u.value.sha1, entry->u.value.peeled);
1757 if (status == PEEL_PEELED || status == PEEL_NON_TAG)
1758 entry->flag |= REF_KNOWS_PEELED;
1759 return status;
1760 }
1761
1762 int peel_ref(const char *refname, unsigned char *sha1)
1763 {
1764 int flag;
1765 unsigned char base[20];
1766
1767 if (current_ref && (current_ref->name == refname
1768 || !strcmp(current_ref->name, refname))) {
1769 if (peel_entry(current_ref, 0))
1770 return -1;
1771 hashcpy(sha1, current_ref->u.value.peeled);
1772 return 0;
1773 }
1774
1775 if (read_ref_full(refname, RESOLVE_REF_READING, base, &flag))
1776 return -1;
1777
1778 /*
1779 * If the reference is packed, read its ref_entry from the
1780 * cache in the hope that we already know its peeled value.
1781 * We only try this optimization on packed references because
1782 * (a) forcing the filling of the loose reference cache could
1783 * be expensive and (b) loose references anyway usually do not
1784 * have REF_KNOWS_PEELED.
1785 */
1786 if (flag & REF_ISPACKED) {
1787 struct ref_entry *r = get_packed_ref(refname);
1788 if (r) {
1789 if (peel_entry(r, 0))
1790 return -1;
1791 hashcpy(sha1, r->u.value.peeled);
1792 return 0;
1793 }
1794 }
1795
1796 return peel_object(base, sha1);
1797 }
1798
1799 struct warn_if_dangling_data {
1800 FILE *fp;
1801 const char *refname;
1802 const struct string_list *refnames;
1803 const char *msg_fmt;
1804 };
1805
1806 static int warn_if_dangling_symref(const char *refname, const unsigned char *sha1,
1807 int flags, void *cb_data)
1808 {
1809 struct warn_if_dangling_data *d = cb_data;
1810 const char *resolves_to;
1811 unsigned char junk[20];
1812
1813 if (!(flags & REF_ISSYMREF))
1814 return 0;
1815
1816 resolves_to = resolve_ref_unsafe(refname, 0, junk, NULL);
1817 if (!resolves_to
1818 || (d->refname
1819 ? strcmp(resolves_to, d->refname)
1820 : !string_list_has_string(d->refnames, resolves_to))) {
1821 return 0;
1822 }
1823
1824 fprintf(d->fp, d->msg_fmt, refname);
1825 fputc('\n', d->fp);
1826 return 0;
1827 }
1828
1829 void warn_dangling_symref(FILE *fp, const char *msg_fmt, const char *refname)
1830 {
1831 struct warn_if_dangling_data data;
1832
1833 data.fp = fp;
1834 data.refname = refname;
1835 data.refnames = NULL;
1836 data.msg_fmt = msg_fmt;
1837 for_each_rawref(warn_if_dangling_symref, &data);
1838 }
1839
1840 void warn_dangling_symrefs(FILE *fp, const char *msg_fmt, const struct string_list *refnames)
1841 {
1842 struct warn_if_dangling_data data;
1843
1844 data.fp = fp;
1845 data.refname = NULL;
1846 data.refnames = refnames;
1847 data.msg_fmt = msg_fmt;
1848 for_each_rawref(warn_if_dangling_symref, &data);
1849 }
1850
1851 /*
1852 * Call fn for each reference in the specified ref_cache, omitting
1853 * references not in the containing_dir of base. fn is called for all
1854 * references, including broken ones. If fn ever returns a non-zero
1855 * value, stop the iteration and return that value; otherwise, return
1856 * 0.
1857 */
1858 static int do_for_each_entry(struct ref_cache *refs, const char *base,
1859 each_ref_entry_fn fn, void *cb_data)
1860 {
1861 struct packed_ref_cache *packed_ref_cache;
1862 struct ref_dir *loose_dir;
1863 struct ref_dir *packed_dir;
1864 int retval = 0;
1865
1866 /*
1867 * We must make sure that all loose refs are read before accessing the
1868 * packed-refs file; this avoids a race condition in which loose refs
1869 * are migrated to the packed-refs file by a simultaneous process, but
1870 * our in-memory view is from before the migration. get_packed_ref_cache()
1871 * takes care of making sure our view is up to date with what is on
1872 * disk.
1873 */
1874 loose_dir = get_loose_refs(refs);
1875 if (base && *base) {
1876 loose_dir = find_containing_dir(loose_dir, base, 0);
1877 }
1878 if (loose_dir)
1879 prime_ref_dir(loose_dir);
1880
1881 packed_ref_cache = get_packed_ref_cache(refs);
1882 acquire_packed_ref_cache(packed_ref_cache);
1883 packed_dir = get_packed_ref_dir(packed_ref_cache);
1884 if (base && *base) {
1885 packed_dir = find_containing_dir(packed_dir, base, 0);
1886 }
1887
1888 if (packed_dir && loose_dir) {
1889 sort_ref_dir(packed_dir);
1890 sort_ref_dir(loose_dir);
1891 retval = do_for_each_entry_in_dirs(
1892 packed_dir, loose_dir, fn, cb_data);
1893 } else if (packed_dir) {
1894 sort_ref_dir(packed_dir);
1895 retval = do_for_each_entry_in_dir(
1896 packed_dir, 0, fn, cb_data);
1897 } else if (loose_dir) {
1898 sort_ref_dir(loose_dir);
1899 retval = do_for_each_entry_in_dir(
1900 loose_dir, 0, fn, cb_data);
1901 }
1902
1903 release_packed_ref_cache(packed_ref_cache);
1904 return retval;
1905 }
1906
1907 /*
1908 * Call fn for each reference in the specified ref_cache for which the
1909 * refname begins with base. If trim is non-zero, then trim that many
1910 * characters off the beginning of each refname before passing the
1911 * refname to fn. flags can be DO_FOR_EACH_INCLUDE_BROKEN to include
1912 * broken references in the iteration. If fn ever returns a non-zero
1913 * value, stop the iteration and return that value; otherwise, return
1914 * 0.
1915 */
1916 static int do_for_each_ref(struct ref_cache *refs, const char *base,
1917 each_ref_fn fn, int trim, int flags, void *cb_data)
1918 {
1919 struct ref_entry_cb data;
1920 data.base = base;
1921 data.trim = trim;
1922 data.flags = flags;
1923 data.fn = fn;
1924 data.cb_data = cb_data;
1925
1926 return do_for_each_entry(refs, base, do_one_ref, &data);
1927 }
1928
1929 static int do_head_ref(const char *submodule, each_ref_fn fn, void *cb_data)
1930 {
1931 unsigned char sha1[20];
1932 int flag;
1933
1934 if (submodule) {
1935 if (resolve_gitlink_ref(submodule, "HEAD", sha1) == 0)
1936 return fn("HEAD", sha1, 0, cb_data);
1937
1938 return 0;
1939 }
1940
1941 if (!read_ref_full("HEAD", RESOLVE_REF_READING, sha1, &flag))
1942 return fn("HEAD", sha1, flag, cb_data);
1943
1944 return 0;
1945 }
1946
1947 int head_ref(each_ref_fn fn, void *cb_data)
1948 {
1949 return do_head_ref(NULL, fn, cb_data);
1950 }
1951
1952 int head_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
1953 {
1954 return do_head_ref(submodule, fn, cb_data);
1955 }
1956
1957 int for_each_ref(each_ref_fn fn, void *cb_data)
1958 {
1959 return do_for_each_ref(&ref_cache, "", fn, 0, 0, cb_data);
1960 }
1961
1962 int for_each_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
1963 {
1964 return do_for_each_ref(get_ref_cache(submodule), "", fn, 0, 0, cb_data);
1965 }
1966
1967 int for_each_ref_in(const char *prefix, each_ref_fn fn, void *cb_data)
1968 {
1969 return do_for_each_ref(&ref_cache, prefix, fn, strlen(prefix), 0, cb_data);
1970 }
1971
1972 int for_each_ref_in_submodule(const char *submodule, const char *prefix,
1973 each_ref_fn fn, void *cb_data)
1974 {
1975 return do_for_each_ref(get_ref_cache(submodule), prefix, fn, strlen(prefix), 0, cb_data);
1976 }
1977
1978 int for_each_tag_ref(each_ref_fn fn, void *cb_data)
1979 {
1980 return for_each_ref_in("refs/tags/", fn, cb_data);
1981 }
1982
1983 int for_each_tag_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
1984 {
1985 return for_each_ref_in_submodule(submodule, "refs/tags/", fn, cb_data);
1986 }
1987
1988 int for_each_branch_ref(each_ref_fn fn, void *cb_data)
1989 {
1990 return for_each_ref_in("refs/heads/", fn, cb_data);
1991 }
1992
1993 int for_each_branch_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
1994 {
1995 return for_each_ref_in_submodule(submodule, "refs/heads/", fn, cb_data);
1996 }
1997
1998 int for_each_remote_ref(each_ref_fn fn, void *cb_data)
1999 {
2000 return for_each_ref_in("refs/remotes/", fn, cb_data);
2001 }
2002
2003 int for_each_remote_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
2004 {
2005 return for_each_ref_in_submodule(submodule, "refs/remotes/", fn, cb_data);
2006 }
2007
2008 int for_each_replace_ref(each_ref_fn fn, void *cb_data)
2009 {
2010 return do_for_each_ref(&ref_cache, "refs/replace/", fn, 13, 0, cb_data);
2011 }
2012
2013 int head_ref_namespaced(each_ref_fn fn, void *cb_data)
2014 {
2015 struct strbuf buf = STRBUF_INIT;
2016 int ret = 0;
2017 unsigned char sha1[20];
2018 int flag;
2019
2020 strbuf_addf(&buf, "%sHEAD", get_git_namespace());
2021 if (!read_ref_full(buf.buf, RESOLVE_REF_READING, sha1, &flag))
2022 ret = fn(buf.buf, sha1, flag, cb_data);
2023 strbuf_release(&buf);
2024
2025 return ret;
2026 }
2027
2028 int for_each_namespaced_ref(each_ref_fn fn, void *cb_data)
2029 {
2030 struct strbuf buf = STRBUF_INIT;
2031 int ret;
2032 strbuf_addf(&buf, "%srefs/", get_git_namespace());
2033 ret = do_for_each_ref(&ref_cache, buf.buf, fn, 0, 0, cb_data);
2034 strbuf_release(&buf);
2035 return ret;
2036 }
2037
2038 int for_each_glob_ref_in(each_ref_fn fn, const char *pattern,
2039 const char *prefix, void *cb_data)
2040 {
2041 struct strbuf real_pattern = STRBUF_INIT;
2042 struct ref_filter filter;
2043 int ret;
2044
2045 if (!prefix && !starts_with(pattern, "refs/"))
2046 strbuf_addstr(&real_pattern, "refs/");
2047 else if (prefix)
2048 strbuf_addstr(&real_pattern, prefix);
2049 strbuf_addstr(&real_pattern, pattern);
2050
2051 if (!has_glob_specials(pattern)) {
2052 /* Append implied '/' '*' if not present. */
2053 if (real_pattern.buf[real_pattern.len - 1] != '/')
2054 strbuf_addch(&real_pattern, '/');
2055 /* No need to check for '*', there is none. */
2056 strbuf_addch(&real_pattern, '*');
2057 }
2058
2059 filter.pattern = real_pattern.buf;
2060 filter.fn = fn;
2061 filter.cb_data = cb_data;
2062 ret = for_each_ref(filter_refs, &filter);
2063
2064 strbuf_release(&real_pattern);
2065 return ret;
2066 }
2067
2068 int for_each_glob_ref(each_ref_fn fn, const char *pattern, void *cb_data)
2069 {
2070 return for_each_glob_ref_in(fn, pattern, NULL, cb_data);
2071 }
2072
2073 int for_each_rawref(each_ref_fn fn, void *cb_data)
2074 {
2075 return do_for_each_ref(&ref_cache, "", fn, 0,
2076 DO_FOR_EACH_INCLUDE_BROKEN, cb_data);
2077 }
2078
2079 const char *prettify_refname(const char *name)
2080 {
2081 return name + (
2082 starts_with(name, "refs/heads/") ? 11 :
2083 starts_with(name, "refs/tags/") ? 10 :
2084 starts_with(name, "refs/remotes/") ? 13 :
2085 0);
2086 }
2087
2088 static const char *ref_rev_parse_rules[] = {
2089 "%.*s",
2090 "refs/%.*s",
2091 "refs/tags/%.*s",
2092 "refs/heads/%.*s",
2093 "refs/remotes/%.*s",
2094 "refs/remotes/%.*s/HEAD",
2095 NULL
2096 };
2097
2098 int refname_match(const char *abbrev_name, const char *full_name)
2099 {
2100 const char **p;
2101 const int abbrev_name_len = strlen(abbrev_name);
2102
2103 for (p = ref_rev_parse_rules; *p; p++) {
2104 if (!strcmp(full_name, mkpath(*p, abbrev_name_len, abbrev_name))) {
2105 return 1;
2106 }
2107 }
2108
2109 return 0;
2110 }
2111
2112 static void unlock_ref(struct ref_lock *lock)
2113 {
2114 /* Do not free lock->lk -- atexit() still looks at them */
2115 if (lock->lk)
2116 rollback_lock_file(lock->lk);
2117 free(lock->ref_name);
2118 free(lock->orig_ref_name);
2119 free(lock);
2120 }
2121
2122 /* This function should make sure errno is meaningful on error */
2123 static struct ref_lock *verify_lock(struct ref_lock *lock,
2124 const unsigned char *old_sha1, int mustexist)
2125 {
2126 if (read_ref_full(lock->ref_name,
2127 mustexist ? RESOLVE_REF_READING : 0,
2128 lock->old_sha1, NULL)) {
2129 int save_errno = errno;
2130 error("Can't verify ref %s", lock->ref_name);
2131 unlock_ref(lock);
2132 errno = save_errno;
2133 return NULL;
2134 }
2135 if (hashcmp(lock->old_sha1, old_sha1)) {
2136 error("Ref %s is at %s but expected %s", lock->ref_name,
2137 sha1_to_hex(lock->old_sha1), sha1_to_hex(old_sha1));
2138 unlock_ref(lock);
2139 errno = EBUSY;
2140 return NULL;
2141 }
2142 return lock;
2143 }
2144
2145 static int remove_empty_directories(const char *file)
2146 {
2147 /* we want to create a file but there is a directory there;
2148 * if that is an empty directory (or a directory that contains
2149 * only empty directories), remove them.
2150 */
2151 struct strbuf path;
2152 int result, save_errno;
2153
2154 strbuf_init(&path, 20);
2155 strbuf_addstr(&path, file);
2156
2157 result = remove_dir_recursively(&path, REMOVE_DIR_EMPTY_ONLY);
2158 save_errno = errno;
2159
2160 strbuf_release(&path);
2161 errno = save_errno;
2162
2163 return result;
2164 }
2165
2166 /*
2167 * *string and *len will only be substituted, and *string returned (for
2168 * later free()ing) if the string passed in is a magic short-hand form
2169 * to name a branch.
2170 */
2171 static char *substitute_branch_name(const char **string, int *len)
2172 {
2173 struct strbuf buf = STRBUF_INIT;
2174 int ret = interpret_branch_name(*string, *len, &buf);
2175
2176 if (ret == *len) {
2177 size_t size;
2178 *string = strbuf_detach(&buf, &size);
2179 *len = size;
2180 return (char *)*string;
2181 }
2182
2183 return NULL;
2184 }
2185
2186 int dwim_ref(const char *str, int len, unsigned char *sha1, char **ref)
2187 {
2188 char *last_branch = substitute_branch_name(&str, &len);
2189 const char **p, *r;
2190 int refs_found = 0;
2191
2192 *ref = NULL;
2193 for (p = ref_rev_parse_rules; *p; p++) {
2194 char fullref[PATH_MAX];
2195 unsigned char sha1_from_ref[20];
2196 unsigned char *this_result;
2197 int flag;
2198
2199 this_result = refs_found ? sha1_from_ref : sha1;
2200 mksnpath(fullref, sizeof(fullref), *p, len, str);
2201 r = resolve_ref_unsafe(fullref, RESOLVE_REF_READING,
2202 this_result, &flag);
2203 if (r) {
2204 if (!refs_found++)
2205 *ref = xstrdup(r);
2206 if (!warn_ambiguous_refs)
2207 break;
2208 } else if ((flag & REF_ISSYMREF) && strcmp(fullref, "HEAD")) {
2209 warning("ignoring dangling symref %s.", fullref);
2210 } else if ((flag & REF_ISBROKEN) && strchr(fullref, '/')) {
2211 warning("ignoring broken ref %s.", fullref);
2212 }
2213 }
2214 free(last_branch);
2215 return refs_found;
2216 }
2217
2218 int dwim_log(const char *str, int len, unsigned char *sha1, char **log)
2219 {
2220 char *last_branch = substitute_branch_name(&str, &len);
2221 const char **p;
2222 int logs_found = 0;
2223
2224 *log = NULL;
2225 for (p = ref_rev_parse_rules; *p; p++) {
2226 unsigned char hash[20];
2227 char path[PATH_MAX];
2228 const char *ref, *it;
2229
2230 mksnpath(path, sizeof(path), *p, len, str);
2231 ref = resolve_ref_unsafe(path, RESOLVE_REF_READING,
2232 hash, NULL);
2233 if (!ref)
2234 continue;
2235 if (reflog_exists(path))
2236 it = path;
2237 else if (strcmp(ref, path) && reflog_exists(ref))
2238 it = ref;
2239 else
2240 continue;
2241 if (!logs_found++) {
2242 *log = xstrdup(it);
2243 hashcpy(sha1, hash);
2244 }
2245 if (!warn_ambiguous_refs)
2246 break;
2247 }
2248 free(last_branch);
2249 return logs_found;
2250 }
2251
2252 /*
2253 * Locks a ref returning the lock on success and NULL on failure.
2254 * On failure errno is set to something meaningful.
2255 */
2256 static struct ref_lock *lock_ref_sha1_basic(const char *refname,
2257 const unsigned char *old_sha1,
2258 const struct string_list *skip,
2259 unsigned int flags, int *type_p)
2260 {
2261 char *ref_file;
2262 const char *orig_refname = refname;
2263 struct ref_lock *lock;
2264 int last_errno = 0;
2265 int type, lflags;
2266 int mustexist = (old_sha1 && !is_null_sha1(old_sha1));
2267 int resolve_flags = 0;
2268 int missing = 0;
2269 int attempts_remaining = 3;
2270
2271 lock = xcalloc(1, sizeof(struct ref_lock));
2272 lock->lock_fd = -1;
2273
2274 if (mustexist)
2275 resolve_flags |= RESOLVE_REF_READING;
2276 if (flags & REF_DELETING) {
2277 resolve_flags |= RESOLVE_REF_ALLOW_BAD_NAME;
2278 if (flags & REF_NODEREF)
2279 resolve_flags |= RESOLVE_REF_NO_RECURSE;
2280 }
2281
2282 refname = resolve_ref_unsafe(refname, resolve_flags,
2283 lock->old_sha1, &type);
2284 if (!refname && errno == EISDIR) {
2285 /* we are trying to lock foo but we used to
2286 * have foo/bar which now does not exist;
2287 * it is normal for the empty directory 'foo'
2288 * to remain.
2289 */
2290 ref_file = git_path("%s", orig_refname);
2291 if (remove_empty_directories(ref_file)) {
2292 last_errno = errno;
2293 error("there are still refs under '%s'", orig_refname);
2294 goto error_return;
2295 }
2296 refname = resolve_ref_unsafe(orig_refname, resolve_flags,
2297 lock->old_sha1, &type);
2298 }
2299 if (type_p)
2300 *type_p = type;
2301 if (!refname) {
2302 last_errno = errno;
2303 error("unable to resolve reference %s: %s",
2304 orig_refname, strerror(errno));
2305 goto error_return;
2306 }
2307 missing = is_null_sha1(lock->old_sha1);
2308 /* When the ref did not exist and we are creating it,
2309 * make sure there is no existing ref that is packed
2310 * whose name begins with our refname, nor a ref whose
2311 * name is a proper prefix of our refname.
2312 */
2313 if (missing &&
2314 !is_refname_available(refname, skip, get_packed_refs(&ref_cache))) {
2315 last_errno = ENOTDIR;
2316 goto error_return;
2317 }
2318
2319 lock->lk = xcalloc(1, sizeof(struct lock_file));
2320
2321 lflags = 0;
2322 if (flags & REF_NODEREF) {
2323 refname = orig_refname;
2324 lflags |= LOCK_NO_DEREF;
2325 }
2326 lock->ref_name = xstrdup(refname);
2327 lock->orig_ref_name = xstrdup(orig_refname);
2328 ref_file = git_path("%s", refname);
2329 if (missing)
2330 lock->force_write = 1;
2331 if ((flags & REF_NODEREF) && (type & REF_ISSYMREF))
2332 lock->force_write = 1;
2333
2334 retry:
2335 switch (safe_create_leading_directories(ref_file)) {
2336 case SCLD_OK:
2337 break; /* success */
2338 case SCLD_VANISHED:
2339 if (--attempts_remaining > 0)
2340 goto retry;
2341 /* fall through */
2342 default:
2343 last_errno = errno;
2344 error("unable to create directory for %s", ref_file);
2345 goto error_return;
2346 }
2347
2348 lock->lock_fd = hold_lock_file_for_update(lock->lk, ref_file, lflags);
2349 if (lock->lock_fd < 0) {
2350 last_errno = errno;
2351 if (errno == ENOENT && --attempts_remaining > 0)
2352 /*
2353 * Maybe somebody just deleted one of the
2354 * directories leading to ref_file. Try
2355 * again:
2356 */
2357 goto retry;
2358 else {
2359 struct strbuf err = STRBUF_INIT;
2360 unable_to_lock_message(ref_file, errno, &err);
2361 error("%s", err.buf);
2362 strbuf_release(&err);
2363 goto error_return;
2364 }
2365 }
2366 return old_sha1 ? verify_lock(lock, old_sha1, mustexist) : lock;
2367
2368 error_return:
2369 unlock_ref(lock);
2370 errno = last_errno;
2371 return NULL;
2372 }
2373
2374 /*
2375 * Write an entry to the packed-refs file for the specified refname.
2376 * If peeled is non-NULL, write it as the entry's peeled value.
2377 */
2378 static void write_packed_entry(FILE *fh, char *refname, unsigned char *sha1,
2379 unsigned char *peeled)
2380 {
2381 fprintf_or_die(fh, "%s %s\n", sha1_to_hex(sha1), refname);
2382 if (peeled)
2383 fprintf_or_die(fh, "^%s\n", sha1_to_hex(peeled));
2384 }
2385
2386 /*
2387 * An each_ref_entry_fn that writes the entry to a packed-refs file.
2388 */
2389 static int write_packed_entry_fn(struct ref_entry *entry, void *cb_data)
2390 {
2391 enum peel_status peel_status = peel_entry(entry, 0);
2392
2393 if (peel_status != PEEL_PEELED && peel_status != PEEL_NON_TAG)
2394 error("internal error: %s is not a valid packed reference!",
2395 entry->name);
2396 write_packed_entry(cb_data, entry->name, entry->u.value.sha1,
2397 peel_status == PEEL_PEELED ?
2398 entry->u.value.peeled : NULL);
2399 return 0;
2400 }
2401
2402 /* This should return a meaningful errno on failure */
2403 int lock_packed_refs(int flags)
2404 {
2405 struct packed_ref_cache *packed_ref_cache;
2406
2407 if (hold_lock_file_for_update(&packlock, git_path("packed-refs"), flags) < 0)
2408 return -1;
2409 /*
2410 * Get the current packed-refs while holding the lock. If the
2411 * packed-refs file has been modified since we last read it,
2412 * this will automatically invalidate the cache and re-read
2413 * the packed-refs file.
2414 */
2415 packed_ref_cache = get_packed_ref_cache(&ref_cache);
2416 packed_ref_cache->lock = &packlock;
2417 /* Increment the reference count to prevent it from being freed: */
2418 acquire_packed_ref_cache(packed_ref_cache);
2419 return 0;
2420 }
2421
2422 /*
2423 * Commit the packed refs changes.
2424 * On error we must make sure that errno contains a meaningful value.
2425 */
2426 int commit_packed_refs(void)
2427 {
2428 struct packed_ref_cache *packed_ref_cache =
2429 get_packed_ref_cache(&ref_cache);
2430 int error = 0;
2431 int save_errno = 0;
2432 FILE *out;
2433
2434 if (!packed_ref_cache->lock)
2435 die("internal error: packed-refs not locked");
2436
2437 out = fdopen_lock_file(packed_ref_cache->lock, "w");
2438 if (!out)
2439 die_errno("unable to fdopen packed-refs descriptor");
2440
2441 fprintf_or_die(out, "%s", PACKED_REFS_HEADER);
2442 do_for_each_entry_in_dir(get_packed_ref_dir(packed_ref_cache),
2443 0, write_packed_entry_fn, out);
2444
2445 if (commit_lock_file(packed_ref_cache->lock)) {
2446 save_errno = errno;
2447 error = -1;
2448 }
2449 packed_ref_cache->lock = NULL;
2450 release_packed_ref_cache(packed_ref_cache);
2451 errno = save_errno;
2452 return error;
2453 }
2454
2455 void rollback_packed_refs(void)
2456 {
2457 struct packed_ref_cache *packed_ref_cache =
2458 get_packed_ref_cache(&ref_cache);
2459
2460 if (!packed_ref_cache->lock)
2461 die("internal error: packed-refs not locked");
2462 rollback_lock_file(packed_ref_cache->lock);
2463 packed_ref_cache->lock = NULL;
2464 release_packed_ref_cache(packed_ref_cache);
2465 clear_packed_ref_cache(&ref_cache);
2466 }
2467
2468 struct ref_to_prune {
2469 struct ref_to_prune *next;
2470 unsigned char sha1[20];
2471 char name[FLEX_ARRAY];
2472 };
2473
2474 struct pack_refs_cb_data {
2475 unsigned int flags;
2476 struct ref_dir *packed_refs;
2477 struct ref_to_prune *ref_to_prune;
2478 };
2479
2480 /*
2481 * An each_ref_entry_fn that is run over loose references only. If
2482 * the loose reference can be packed, add an entry in the packed ref
2483 * cache. If the reference should be pruned, also add it to
2484 * ref_to_prune in the pack_refs_cb_data.
2485 */
2486 static int pack_if_possible_fn(struct ref_entry *entry, void *cb_data)
2487 {
2488 struct pack_refs_cb_data *cb = cb_data;
2489 enum peel_status peel_status;
2490 struct ref_entry *packed_entry;
2491 int is_tag_ref = starts_with(entry->name, "refs/tags/");
2492
2493 /* ALWAYS pack tags */
2494 if (!(cb->flags & PACK_REFS_ALL) && !is_tag_ref)
2495 return 0;
2496
2497 /* Do not pack symbolic or broken refs: */
2498 if ((entry->flag & REF_ISSYMREF) || !ref_resolves_to_object(entry))
2499 return 0;
2500
2501 /* Add a packed ref cache entry equivalent to the loose entry. */
2502 peel_status = peel_entry(entry, 1);
2503 if (peel_status != PEEL_PEELED && peel_status != PEEL_NON_TAG)
2504 die("internal error peeling reference %s (%s)",
2505 entry->name, sha1_to_hex(entry->u.value.sha1));
2506 packed_entry = find_ref(cb->packed_refs, entry->name);
2507 if (packed_entry) {
2508 /* Overwrite existing packed entry with info from loose entry */
2509 packed_entry->flag = REF_ISPACKED | REF_KNOWS_PEELED;
2510 hashcpy(packed_entry->u.value.sha1, entry->u.value.sha1);
2511 } else {
2512 packed_entry = create_ref_entry(entry->name, entry->u.value.sha1,
2513 REF_ISPACKED | REF_KNOWS_PEELED, 0);
2514 add_ref(cb->packed_refs, packed_entry);
2515 }
2516 hashcpy(packed_entry->u.value.peeled, entry->u.value.peeled);
2517
2518 /* Schedule the loose reference for pruning if requested. */
2519 if ((cb->flags & PACK_REFS_PRUNE)) {
2520 int namelen = strlen(entry->name) + 1;
2521 struct ref_to_prune *n = xcalloc(1, sizeof(*n) + namelen);
2522 hashcpy(n->sha1, entry->u.value.sha1);
2523 strcpy(n->name, entry->name);
2524 n->next = cb->ref_to_prune;
2525 cb->ref_to_prune = n;
2526 }
2527 return 0;
2528 }
2529
2530 /*
2531 * Remove empty parents, but spare refs/ and immediate subdirs.
2532 * Note: munges *name.
2533 */
2534 static void try_remove_empty_parents(char *name)
2535 {
2536 char *p, *q;
2537 int i;
2538 p = name;
2539 for (i = 0; i < 2; i++) { /* refs/{heads,tags,...}/ */
2540 while (*p && *p != '/')
2541 p++;
2542 /* tolerate duplicate slashes; see check_refname_format() */
2543 while (*p == '/')
2544 p++;
2545 }
2546 for (q = p; *q; q++)
2547 ;
2548 while (1) {
2549 while (q > p && *q != '/')
2550 q--;
2551 while (q > p && *(q-1) == '/')
2552 q--;
2553 if (q == p)
2554 break;
2555 *q = '\0';
2556 if (rmdir(git_path("%s", name)))
2557 break;
2558 }
2559 }
2560
2561 /* make sure nobody touched the ref, and unlink */
2562 static void prune_ref(struct ref_to_prune *r)
2563 {
2564 struct ref_transaction *transaction;
2565 struct strbuf err = STRBUF_INIT;
2566
2567 if (check_refname_format(r->name, 0))
2568 return;
2569
2570 transaction = ref_transaction_begin(&err);
2571 if (!transaction ||
2572 ref_transaction_delete(transaction, r->name, r->sha1,
2573 REF_ISPRUNING, 1, NULL, &err) ||
2574 ref_transaction_commit(transaction, &err)) {
2575 ref_transaction_free(transaction);
2576 error("%s", err.buf);
2577 strbuf_release(&err);
2578 return;
2579 }
2580 ref_transaction_free(transaction);
2581 strbuf_release(&err);
2582 try_remove_empty_parents(r->name);
2583 }
2584
2585 static void prune_refs(struct ref_to_prune *r)
2586 {
2587 while (r) {
2588 prune_ref(r);
2589 r = r->next;
2590 }
2591 }
2592
2593 int pack_refs(unsigned int flags)
2594 {
2595 struct pack_refs_cb_data cbdata;
2596
2597 memset(&cbdata, 0, sizeof(cbdata));
2598 cbdata.flags = flags;
2599
2600 lock_packed_refs(LOCK_DIE_ON_ERROR);
2601 cbdata.packed_refs = get_packed_refs(&ref_cache);
2602
2603 do_for_each_entry_in_dir(get_loose_refs(&ref_cache), 0,
2604 pack_if_possible_fn, &cbdata);
2605
2606 if (commit_packed_refs())
2607 die_errno("unable to overwrite old ref-pack file");
2608
2609 prune_refs(cbdata.ref_to_prune);
2610 return 0;
2611 }
2612
2613 /*
2614 * If entry is no longer needed in packed-refs, add it to the string
2615 * list pointed to by cb_data. Reasons for deleting entries:
2616 *
2617 * - Entry is broken.
2618 * - Entry is overridden by a loose ref.
2619 * - Entry does not point at a valid object.
2620 *
2621 * In the first and third cases, also emit an error message because these
2622 * are indications of repository corruption.
2623 */
2624 static int curate_packed_ref_fn(struct ref_entry *entry, void *cb_data)
2625 {
2626 struct string_list *refs_to_delete = cb_data;
2627
2628 if (entry->flag & REF_ISBROKEN) {
2629 /* This shouldn't happen to packed refs. */
2630 error("%s is broken!", entry->name);
2631 string_list_append(refs_to_delete, entry->name);
2632 return 0;
2633 }
2634 if (!has_sha1_file(entry->u.value.sha1)) {
2635 unsigned char sha1[20];
2636 int flags;
2637
2638 if (read_ref_full(entry->name, 0, sha1, &flags))
2639 /* We should at least have found the packed ref. */
2640 die("Internal error");
2641 if ((flags & REF_ISSYMREF) || !(flags & REF_ISPACKED)) {
2642 /*
2643 * This packed reference is overridden by a
2644 * loose reference, so it is OK that its value
2645 * is no longer valid; for example, it might
2646 * refer to an object that has been garbage
2647 * collected. For this purpose we don't even
2648 * care whether the loose reference itself is
2649 * invalid, broken, symbolic, etc. Silently
2650 * remove the packed reference.
2651 */
2652 string_list_append(refs_to_delete, entry->name);
2653 return 0;
2654 }
2655 /*
2656 * There is no overriding loose reference, so the fact
2657 * that this reference doesn't refer to a valid object
2658 * indicates some kind of repository corruption.
2659 * Report the problem, then omit the reference from
2660 * the output.
2661 */
2662 error("%s does not point to a valid object!", entry->name);
2663 string_list_append(refs_to_delete, entry->name);
2664 return 0;
2665 }
2666
2667 return 0;
2668 }
2669
2670 int repack_without_refs(struct string_list *refnames, struct strbuf *err)
2671 {
2672 struct ref_dir *packed;
2673 struct string_list refs_to_delete = STRING_LIST_INIT_DUP;
2674 struct string_list_item *refname, *ref_to_delete;
2675 int ret, needs_repacking = 0, removed = 0;
2676
2677 assert(err);
2678
2679 /* Look for a packed ref */
2680 for_each_string_list_item(refname, refnames) {
2681 if (get_packed_ref(refname->string)) {
2682 needs_repacking = 1;
2683 break;
2684 }
2685 }
2686
2687 /* Avoid locking if we have nothing to do */
2688 if (!needs_repacking)
2689 return 0; /* no refname exists in packed refs */
2690
2691 if (lock_packed_refs(0)) {
2692 unable_to_lock_message(git_path("packed-refs"), errno, err);
2693 return -1;
2694 }
2695 packed = get_packed_refs(&ref_cache);
2696
2697 /* Remove refnames from the cache */
2698 for_each_string_list_item(refname, refnames)
2699 if (remove_entry(packed, refname->string) != -1)
2700 removed = 1;
2701 if (!removed) {
2702 /*
2703 * All packed entries disappeared while we were
2704 * acquiring the lock.
2705 */
2706 rollback_packed_refs();
2707 return 0;
2708 }
2709
2710 /* Remove any other accumulated cruft */
2711 do_for_each_entry_in_dir(packed, 0, curate_packed_ref_fn, &refs_to_delete);
2712 for_each_string_list_item(ref_to_delete, &refs_to_delete) {
2713 if (remove_entry(packed, ref_to_delete->string) == -1)
2714 die("internal error");
2715 }
2716
2717 /* Write what remains */
2718 ret = commit_packed_refs();
2719 if (ret)
2720 strbuf_addf(err, "unable to overwrite old ref-pack file: %s",
2721 strerror(errno));
2722 return ret;
2723 }
2724
2725 static int delete_ref_loose(struct ref_lock *lock, int flag, struct strbuf *err)
2726 {
2727 assert(err);
2728
2729 if (!(flag & REF_ISPACKED) || flag & REF_ISSYMREF) {
2730 /*
2731 * loose. The loose file name is the same as the
2732 * lockfile name, minus ".lock":
2733 */
2734 char *loose_filename = get_locked_file_path(lock->lk);
2735 int res = unlink_or_msg(loose_filename, err);
2736 free(loose_filename);
2737 if (res)
2738 return 1;
2739 }
2740 return 0;
2741 }
2742
2743 int delete_ref(const char *refname, const unsigned char *sha1, unsigned int flags)
2744 {
2745 struct ref_transaction *transaction;
2746 struct strbuf err = STRBUF_INIT;
2747
2748 transaction = ref_transaction_begin(&err);
2749 if (!transaction ||
2750 ref_transaction_delete(transaction, refname, sha1, flags,
2751 sha1 && !is_null_sha1(sha1), NULL, &err) ||
2752 ref_transaction_commit(transaction, &err)) {
2753 error("%s", err.buf);
2754 ref_transaction_free(transaction);
2755 strbuf_release(&err);
2756 return 1;
2757 }
2758 ref_transaction_free(transaction);
2759 strbuf_release(&err);
2760 return 0;
2761 }
2762
2763 /*
2764 * People using contrib's git-new-workdir have .git/logs/refs ->
2765 * /some/other/path/.git/logs/refs, and that may live on another device.
2766 *
2767 * IOW, to avoid cross device rename errors, the temporary renamed log must
2768 * live into logs/refs.
2769 */
2770 #define TMP_RENAMED_LOG "logs/refs/.tmp-renamed-log"
2771
2772 static int rename_tmp_log(const char *newrefname)
2773 {
2774 int attempts_remaining = 4;
2775
2776 retry:
2777 switch (safe_create_leading_directories(git_path("logs/%s", newrefname))) {
2778 case SCLD_OK:
2779 break; /* success */
2780 case SCLD_VANISHED:
2781 if (--attempts_remaining > 0)
2782 goto retry;
2783 /* fall through */
2784 default:
2785 error("unable to create directory for %s", newrefname);
2786 return -1;
2787 }
2788
2789 if (rename(git_path(TMP_RENAMED_LOG), git_path("logs/%s", newrefname))) {
2790 if ((errno==EISDIR || errno==ENOTDIR) && --attempts_remaining > 0) {
2791 /*
2792 * rename(a, b) when b is an existing
2793 * directory ought to result in ISDIR, but
2794 * Solaris 5.8 gives ENOTDIR. Sheesh.
2795 */
2796 if (remove_empty_directories(git_path("logs/%s", newrefname))) {
2797 error("Directory not empty: logs/%s", newrefname);
2798 return -1;
2799 }
2800 goto retry;
2801 } else if (errno == ENOENT && --attempts_remaining > 0) {
2802 /*
2803 * Maybe another process just deleted one of
2804 * the directories in the path to newrefname.
2805 * Try again from the beginning.
2806 */
2807 goto retry;
2808 } else {
2809 error("unable to move logfile "TMP_RENAMED_LOG" to logs/%s: %s",
2810 newrefname, strerror(errno));
2811 return -1;
2812 }
2813 }
2814 return 0;
2815 }
2816
2817 static int rename_ref_available(const char *oldname, const char *newname)
2818 {
2819 struct string_list skip = STRING_LIST_INIT_NODUP;
2820 int ret;
2821
2822 string_list_insert(&skip, oldname);
2823 ret = is_refname_available(newname, &skip, get_packed_refs(&ref_cache))
2824 && is_refname_available(newname, &skip, get_loose_refs(&ref_cache));
2825 string_list_clear(&skip, 0);
2826 return ret;
2827 }
2828
2829 static int write_ref_sha1(struct ref_lock *lock, const unsigned char *sha1,
2830 const char *logmsg);
2831
2832 int rename_ref(const char *oldrefname, const char *newrefname, const char *logmsg)
2833 {
2834 unsigned char sha1[20], orig_sha1[20];
2835 int flag = 0, logmoved = 0;
2836 struct ref_lock *lock;
2837 struct stat loginfo;
2838 int log = !lstat(git_path("logs/%s", oldrefname), &loginfo);
2839 const char *symref = NULL;
2840
2841 if (log && S_ISLNK(loginfo.st_mode))
2842 return error("reflog for %s is a symlink", oldrefname);
2843
2844 symref = resolve_ref_unsafe(oldrefname, RESOLVE_REF_READING,
2845 orig_sha1, &flag);
2846 if (flag & REF_ISSYMREF)
2847 return error("refname %s is a symbolic ref, renaming it is not supported",
2848 oldrefname);
2849 if (!symref)
2850 return error("refname %s not found", oldrefname);
2851
2852 if (!rename_ref_available(oldrefname, newrefname))
2853 return 1;
2854
2855 if (log && rename(git_path("logs/%s", oldrefname), git_path(TMP_RENAMED_LOG)))
2856 return error("unable to move logfile logs/%s to "TMP_RENAMED_LOG": %s",
2857 oldrefname, strerror(errno));
2858
2859 if (delete_ref(oldrefname, orig_sha1, REF_NODEREF)) {
2860 error("unable to delete old %s", oldrefname);
2861 goto rollback;
2862 }
2863
2864 if (!read_ref_full(newrefname, RESOLVE_REF_READING, sha1, NULL) &&
2865 delete_ref(newrefname, sha1, REF_NODEREF)) {
2866 if (errno==EISDIR) {
2867 if (remove_empty_directories(git_path("%s", newrefname))) {
2868 error("Directory not empty: %s", newrefname);
2869 goto rollback;
2870 }
2871 } else {
2872 error("unable to delete existing %s", newrefname);
2873 goto rollback;
2874 }
2875 }
2876
2877 if (log && rename_tmp_log(newrefname))
2878 goto rollback;
2879
2880 logmoved = log;
2881
2882 lock = lock_ref_sha1_basic(newrefname, NULL, NULL, 0, NULL);
2883 if (!lock) {
2884 error("unable to lock %s for update", newrefname);
2885 goto rollback;
2886 }
2887 lock->force_write = 1;
2888 hashcpy(lock->old_sha1, orig_sha1);
2889 if (write_ref_sha1(lock, orig_sha1, logmsg)) {
2890 error("unable to write current sha1 into %s", newrefname);
2891 goto rollback;
2892 }
2893
2894 return 0;
2895
2896 rollback:
2897 lock = lock_ref_sha1_basic(oldrefname, NULL, NULL, 0, NULL);
2898 if (!lock) {
2899 error("unable to lock %s for rollback", oldrefname);
2900 goto rollbacklog;
2901 }
2902
2903 lock->force_write = 1;
2904 flag = log_all_ref_updates;
2905 log_all_ref_updates = 0;
2906 if (write_ref_sha1(lock, orig_sha1, NULL))
2907 error("unable to write current sha1 into %s", oldrefname);
2908 log_all_ref_updates = flag;
2909
2910 rollbacklog:
2911 if (logmoved && rename(git_path("logs/%s", newrefname), git_path("logs/%s", oldrefname)))
2912 error("unable to restore logfile %s from %s: %s",
2913 oldrefname, newrefname, strerror(errno));
2914 if (!logmoved && log &&
2915 rename(git_path(TMP_RENAMED_LOG), git_path("logs/%s", oldrefname)))
2916 error("unable to restore logfile %s from "TMP_RENAMED_LOG": %s",
2917 oldrefname, strerror(errno));
2918
2919 return 1;
2920 }
2921
2922 static int close_ref(struct ref_lock *lock)
2923 {
2924 if (close_lock_file(lock->lk))
2925 return -1;
2926 lock->lock_fd = -1;
2927 return 0;
2928 }
2929
2930 static int commit_ref(struct ref_lock *lock)
2931 {
2932 if (commit_lock_file(lock->lk))
2933 return -1;
2934 lock->lock_fd = -1;
2935 return 0;
2936 }
2937
2938 /*
2939 * copy the reflog message msg to buf, which has been allocated sufficiently
2940 * large, while cleaning up the whitespaces. Especially, convert LF to space,
2941 * because reflog file is one line per entry.
2942 */
2943 static int copy_msg(char *buf, const char *msg)
2944 {
2945 char *cp = buf;
2946 char c;
2947 int wasspace = 1;
2948
2949 *cp++ = '\t';
2950 while ((c = *msg++)) {
2951 if (wasspace && isspace(c))
2952 continue;
2953 wasspace = isspace(c);
2954 if (wasspace)
2955 c = ' ';
2956 *cp++ = c;
2957 }
2958 while (buf < cp && isspace(cp[-1]))
2959 cp--;
2960 *cp++ = '\n';
2961 return cp - buf;
2962 }
2963
2964 /* This function must set a meaningful errno on failure */
2965 int log_ref_setup(const char *refname, char *logfile, int bufsize)
2966 {
2967 int logfd, oflags = O_APPEND | O_WRONLY;
2968
2969 git_snpath(logfile, bufsize, "logs/%s", refname);
2970 if (log_all_ref_updates &&
2971 (starts_with(refname, "refs/heads/") ||
2972 starts_with(refname, "refs/remotes/") ||
2973 starts_with(refname, "refs/notes/") ||
2974 !strcmp(refname, "HEAD"))) {
2975 if (safe_create_leading_directories(logfile) < 0) {
2976 int save_errno = errno;
2977 error("unable to create directory for %s", logfile);
2978 errno = save_errno;
2979 return -1;
2980 }
2981 oflags |= O_CREAT;
2982 }
2983
2984 logfd = open(logfile, oflags, 0666);
2985 if (logfd < 0) {
2986 if (!(oflags & O_CREAT) && (errno == ENOENT || errno == EISDIR))
2987 return 0;
2988
2989 if (errno == EISDIR) {
2990 if (remove_empty_directories(logfile)) {
2991 int save_errno = errno;
2992 error("There are still logs under '%s'",
2993 logfile);
2994 errno = save_errno;
2995 return -1;
2996 }
2997 logfd = open(logfile, oflags, 0666);
2998 }
2999
3000 if (logfd < 0) {
3001 int save_errno = errno;
3002 error("Unable to append to %s: %s", logfile,
3003 strerror(errno));
3004 errno = save_errno;
3005 return -1;
3006 }
3007 }
3008
3009 adjust_shared_perm(logfile);
3010 close(logfd);
3011 return 0;
3012 }
3013
3014 static int log_ref_write_fd(int fd, const unsigned char *old_sha1,
3015 const unsigned char *new_sha1,
3016 const char *committer, const char *msg)
3017 {
3018 int msglen, written;
3019 unsigned maxlen, len;
3020 char *logrec;
3021
3022 msglen = msg ? strlen(msg) : 0;
3023 maxlen = strlen(committer) + msglen + 100;
3024 logrec = xmalloc(maxlen);
3025 len = sprintf(logrec, "%s %s %s\n",
3026 sha1_to_hex(old_sha1),
3027 sha1_to_hex(new_sha1),
3028 committer);
3029 if (msglen)
3030 len += copy_msg(logrec + len - 1, msg) - 1;
3031
3032 written = len <= maxlen ? write_in_full(fd, logrec, len) : -1;
3033 free(logrec);
3034 if (written != len)
3035 return -1;
3036
3037 return 0;
3038 }
3039
3040 static int log_ref_write(const char *refname, const unsigned char *old_sha1,
3041 const unsigned char *new_sha1, const char *msg)
3042 {
3043 int logfd, result, oflags = O_APPEND | O_WRONLY;
3044 char log_file[PATH_MAX];
3045
3046 if (log_all_ref_updates < 0)
3047 log_all_ref_updates = !is_bare_repository();
3048
3049 result = log_ref_setup(refname, log_file, sizeof(log_file));
3050 if (result)
3051 return result;
3052
3053 logfd = open(log_file, oflags);
3054 if (logfd < 0)
3055 return 0;
3056 result = log_ref_write_fd(logfd, old_sha1, new_sha1,
3057 git_committer_info(0), msg);
3058 if (result) {
3059 int save_errno = errno;
3060 close(logfd);
3061 error("Unable to append to %s", log_file);
3062 errno = save_errno;
3063 return -1;
3064 }
3065 if (close(logfd)) {
3066 int save_errno = errno;
3067 error("Unable to append to %s", log_file);
3068 errno = save_errno;
3069 return -1;
3070 }
3071 return 0;
3072 }
3073
3074 int is_branch(const char *refname)
3075 {
3076 return !strcmp(refname, "HEAD") || starts_with(refname, "refs/heads/");
3077 }
3078
3079 /*
3080 * Write sha1 into the ref specified by the lock. Make sure that errno
3081 * is sane on error.
3082 */
3083 static int write_ref_sha1(struct ref_lock *lock,
3084 const unsigned char *sha1, const char *logmsg)
3085 {
3086 static char term = '\n';
3087 struct object *o;
3088
3089 if (!lock) {
3090 errno = EINVAL;
3091 return -1;
3092 }
3093 if (!lock->force_write && !hashcmp(lock->old_sha1, sha1)) {
3094 unlock_ref(lock);
3095 return 0;
3096 }
3097 o = parse_object(sha1);
3098 if (!o) {
3099 error("Trying to write ref %s with nonexistent object %s",
3100 lock->ref_name, sha1_to_hex(sha1));
3101 unlock_ref(lock);
3102 errno = EINVAL;
3103 return -1;
3104 }
3105 if (o->type != OBJ_COMMIT && is_branch(lock->ref_name)) {
3106 error("Trying to write non-commit object %s to branch %s",
3107 sha1_to_hex(sha1), lock->ref_name);
3108 unlock_ref(lock);
3109 errno = EINVAL;
3110 return -1;
3111 }
3112 if (write_in_full(lock->lock_fd, sha1_to_hex(sha1), 40) != 40 ||
3113 write_in_full(lock->lock_fd, &term, 1) != 1 ||
3114 close_ref(lock) < 0) {
3115 int save_errno = errno;
3116 error("Couldn't write %s", lock->lk->filename.buf);
3117 unlock_ref(lock);
3118 errno = save_errno;
3119 return -1;
3120 }
3121 clear_loose_ref_cache(&ref_cache);
3122 if (log_ref_write(lock->ref_name, lock->old_sha1, sha1, logmsg) < 0 ||
3123 (strcmp(lock->ref_name, lock->orig_ref_name) &&
3124 log_ref_write(lock->orig_ref_name, lock->old_sha1, sha1, logmsg) < 0)) {
3125 unlock_ref(lock);
3126 return -1;
3127 }
3128 if (strcmp(lock->orig_ref_name, "HEAD") != 0) {
3129 /*
3130 * Special hack: If a branch is updated directly and HEAD
3131 * points to it (may happen on the remote side of a push
3132 * for example) then logically the HEAD reflog should be
3133 * updated too.
3134 * A generic solution implies reverse symref information,
3135 * but finding all symrefs pointing to the given branch
3136 * would be rather costly for this rare event (the direct
3137 * update of a branch) to be worth it. So let's cheat and
3138 * check with HEAD only which should cover 99% of all usage
3139 * scenarios (even 100% of the default ones).
3140 */
3141 unsigned char head_sha1[20];
3142 int head_flag;
3143 const char *head_ref;
3144 head_ref = resolve_ref_unsafe("HEAD", RESOLVE_REF_READING,
3145 head_sha1, &head_flag);
3146 if (head_ref && (head_flag & REF_ISSYMREF) &&
3147 !strcmp(head_ref, lock->ref_name))
3148 log_ref_write("HEAD", lock->old_sha1, sha1, logmsg);
3149 }
3150 if (commit_ref(lock)) {
3151 error("Couldn't set %s", lock->ref_name);
3152 unlock_ref(lock);
3153 return -1;
3154 }
3155 unlock_ref(lock);
3156 return 0;
3157 }
3158
3159 int create_symref(const char *ref_target, const char *refs_heads_master,
3160 const char *logmsg)
3161 {
3162 const char *lockpath;
3163 char ref[1000];
3164 int fd, len, written;
3165 char *git_HEAD = git_pathdup("%s", ref_target);
3166 unsigned char old_sha1[20], new_sha1[20];
3167
3168 if (logmsg && read_ref(ref_target, old_sha1))
3169 hashclr(old_sha1);
3170
3171 if (safe_create_leading_directories(git_HEAD) < 0)
3172 return error("unable to create directory for %s", git_HEAD);
3173
3174 #ifndef NO_SYMLINK_HEAD
3175 if (prefer_symlink_refs) {
3176 unlink(git_HEAD);
3177 if (!symlink(refs_heads_master, git_HEAD))
3178 goto done;
3179 fprintf(stderr, "no symlink - falling back to symbolic ref\n");
3180 }
3181 #endif
3182
3183 len = snprintf(ref, sizeof(ref), "ref: %s\n", refs_heads_master);
3184 if (sizeof(ref) <= len) {
3185 error("refname too long: %s", refs_heads_master);
3186 goto error_free_return;
3187 }
3188 lockpath = mkpath("%s.lock", git_HEAD);
3189 fd = open(lockpath, O_CREAT | O_EXCL | O_WRONLY, 0666);
3190 if (fd < 0) {
3191 error("Unable to open %s for writing", lockpath);
3192 goto error_free_return;
3193 }
3194 written = write_in_full(fd, ref, len);
3195 if (close(fd) != 0 || written != len) {
3196 error("Unable to write to %s", lockpath);
3197 goto error_unlink_return;
3198 }
3199 if (rename(lockpath, git_HEAD) < 0) {
3200 error("Unable to create %s", git_HEAD);
3201 goto error_unlink_return;
3202 }
3203 if (adjust_shared_perm(git_HEAD)) {
3204 error("Unable to fix permissions on %s", lockpath);
3205 error_unlink_return:
3206 unlink_or_warn(lockpath);
3207 error_free_return:
3208 free(git_HEAD);
3209 return -1;
3210 }
3211
3212 #ifndef NO_SYMLINK_HEAD
3213 done:
3214 #endif
3215 if (logmsg && !read_ref(refs_heads_master, new_sha1))
3216 log_ref_write(ref_target, old_sha1, new_sha1, logmsg);
3217
3218 free(git_HEAD);
3219 return 0;
3220 }
3221
3222 struct read_ref_at_cb {
3223 const char *refname;
3224 unsigned long at_time;
3225 int cnt;
3226 int reccnt;
3227 unsigned char *sha1;
3228 int found_it;
3229
3230 unsigned char osha1[20];
3231 unsigned char nsha1[20];
3232 int tz;
3233 unsigned long date;
3234 char **msg;
3235 unsigned long *cutoff_time;
3236 int *cutoff_tz;
3237 int *cutoff_cnt;
3238 };
3239
3240 static int read_ref_at_ent(unsigned char *osha1, unsigned char *nsha1,
3241 const char *email, unsigned long timestamp, int tz,
3242 const char *message, void *cb_data)
3243 {
3244 struct read_ref_at_cb *cb = cb_data;
3245
3246 cb->reccnt++;
3247 cb->tz = tz;
3248 cb->date = timestamp;
3249
3250 if (timestamp <= cb->at_time || cb->cnt == 0) {
3251 if (cb->msg)
3252 *cb->msg = xstrdup(message);
3253 if (cb->cutoff_time)
3254 *cb->cutoff_time = timestamp;
3255 if (cb->cutoff_tz)
3256 *cb->cutoff_tz = tz;
3257 if (cb->cutoff_cnt)
3258 *cb->cutoff_cnt = cb->reccnt - 1;
3259 /*
3260 * we have not yet updated cb->[n|o]sha1 so they still
3261 * hold the values for the previous record.
3262 */
3263 if (!is_null_sha1(cb->osha1)) {
3264 hashcpy(cb->sha1, nsha1);
3265 if (hashcmp(cb->osha1, nsha1))
3266 warning("Log for ref %s has gap after %s.",
3267 cb->refname, show_date(cb->date, cb->tz, DATE_RFC2822));
3268 }
3269 else if (cb->date == cb->at_time)
3270 hashcpy(cb->sha1, nsha1);
3271 else if (hashcmp(nsha1, cb->sha1))
3272 warning("Log for ref %s unexpectedly ended on %s.",
3273 cb->refname, show_date(cb->date, cb->tz,
3274 DATE_RFC2822));
3275 hashcpy(cb->osha1, osha1);
3276 hashcpy(cb->nsha1, nsha1);
3277 cb->found_it = 1;
3278 return 1;
3279 }
3280 hashcpy(cb->osha1, osha1);
3281 hashcpy(cb->nsha1, nsha1);
3282 if (cb->cnt > 0)
3283 cb->cnt--;
3284 return 0;
3285 }
3286
3287 static int read_ref_at_ent_oldest(unsigned char *osha1, unsigned char *nsha1,
3288 const char *email, unsigned long timestamp,
3289 int tz, const char *message, void *cb_data)
3290 {
3291 struct read_ref_at_cb *cb = cb_data;
3292
3293 if (cb->msg)
3294 *cb->msg = xstrdup(message);
3295 if (cb->cutoff_time)
3296 *cb->cutoff_time = timestamp;
3297 if (cb->cutoff_tz)
3298 *cb->cutoff_tz = tz;
3299 if (cb->cutoff_cnt)
3300 *cb->cutoff_cnt = cb->reccnt;
3301 hashcpy(cb->sha1, osha1);
3302 if (is_null_sha1(cb->sha1))
3303 hashcpy(cb->sha1, nsha1);
3304 /* We just want the first entry */
3305 return 1;
3306 }
3307
3308 int read_ref_at(const char *refname, unsigned int flags, unsigned long at_time, int cnt,
3309 unsigned char *sha1, char **msg,
3310 unsigned long *cutoff_time, int *cutoff_tz, int *cutoff_cnt)
3311 {
3312 struct read_ref_at_cb cb;
3313
3314 memset(&cb, 0, sizeof(cb));
3315 cb.refname = refname;
3316 cb.at_time = at_time;
3317 cb.cnt = cnt;
3318 cb.msg = msg;
3319 cb.cutoff_time = cutoff_time;
3320 cb.cutoff_tz = cutoff_tz;
3321 cb.cutoff_cnt = cutoff_cnt;
3322 cb.sha1 = sha1;
3323
3324 for_each_reflog_ent_reverse(refname, read_ref_at_ent, &cb);
3325
3326 if (!cb.reccnt) {
3327 if (flags & GET_SHA1_QUIETLY)
3328 exit(128);
3329 else
3330 die("Log for %s is empty.", refname);
3331 }
3332 if (cb.found_it)
3333 return 0;
3334
3335 for_each_reflog_ent(refname, read_ref_at_ent_oldest, &cb);
3336
3337 return 1;
3338 }
3339
3340 int reflog_exists(const char *refname)
3341 {
3342 struct stat st;
3343
3344 return !lstat(git_path("logs/%s", refname), &st) &&
3345 S_ISREG(st.st_mode);
3346 }
3347
3348 int delete_reflog(const char *refname)
3349 {
3350 return remove_path(git_path("logs/%s", refname));
3351 }
3352
3353 static int show_one_reflog_ent(struct strbuf *sb, each_reflog_ent_fn fn, void *cb_data)
3354 {
3355 unsigned char osha1[20], nsha1[20];
3356 char *email_end, *message;
3357 unsigned long timestamp;
3358 int tz;
3359
3360 /* old SP new SP name <email> SP time TAB msg LF */
3361 if (sb->len < 83 || sb->buf[sb->len - 1] != '\n' ||
3362 get_sha1_hex(sb->buf, osha1) || sb->buf[40] != ' ' ||
3363 get_sha1_hex(sb->buf + 41, nsha1) || sb->buf[81] != ' ' ||
3364 !(email_end = strchr(sb->buf + 82, '>')) ||
3365 email_end[1] != ' ' ||
3366 !(timestamp = strtoul(email_end + 2, &message, 10)) ||
3367 !message || message[0] != ' ' ||
3368 (message[1] != '+' && message[1] != '-') ||
3369 !isdigit(message[2]) || !isdigit(message[3]) ||
3370 !isdigit(message[4]) || !isdigit(message[5]))
3371 return 0; /* corrupt? */
3372 email_end[1] = '\0';
3373 tz = strtol(message + 1, NULL, 10);
3374 if (message[6] != '\t')
3375 message += 6;
3376 else
3377 message += 7;
3378 return fn(osha1, nsha1, sb->buf + 82, timestamp, tz, message, cb_data);
3379 }
3380
3381 static char *find_beginning_of_line(char *bob, char *scan)
3382 {
3383 while (bob < scan && *(--scan) != '\n')
3384 ; /* keep scanning backwards */
3385 /*
3386 * Return either beginning of the buffer, or LF at the end of
3387 * the previous line.
3388 */
3389 return scan;
3390 }
3391
3392 int for_each_reflog_ent_reverse(const char *refname, each_reflog_ent_fn fn, void *cb_data)
3393 {
3394 struct strbuf sb = STRBUF_INIT;
3395 FILE *logfp;
3396 long pos;
3397 int ret = 0, at_tail = 1;
3398
3399 logfp = fopen(git_path("logs/%s", refname), "r");
3400 if (!logfp)
3401 return -1;
3402
3403 /* Jump to the end */
3404 if (fseek(logfp, 0, SEEK_END) < 0)
3405 return error("cannot seek back reflog for %s: %s",
3406 refname, strerror(errno));
3407 pos = ftell(logfp);
3408 while (!ret && 0 < pos) {
3409 int cnt;
3410 size_t nread;
3411 char buf[BUFSIZ];
3412 char *endp, *scanp;
3413
3414 /* Fill next block from the end */
3415 cnt = (sizeof(buf) < pos) ? sizeof(buf) : pos;
3416 if (fseek(logfp, pos - cnt, SEEK_SET))
3417 return error("cannot seek back reflog for %s: %s",
3418 refname, strerror(errno));
3419 nread = fread(buf, cnt, 1, logfp);
3420 if (nread != 1)
3421 return error("cannot read %d bytes from reflog for %s: %s",
3422 cnt, refname, strerror(errno));
3423 pos -= cnt;
3424
3425 scanp = endp = buf + cnt;
3426 if (at_tail && scanp[-1] == '\n')
3427 /* Looking at the final LF at the end of the file */
3428 scanp--;
3429 at_tail = 0;
3430
3431 while (buf < scanp) {
3432 /*
3433 * terminating LF of the previous line, or the beginning
3434 * of the buffer.
3435 */
3436 char *bp;
3437
3438 bp = find_beginning_of_line(buf, scanp);
3439
3440 if (*bp == '\n') {
3441 /*
3442 * The newline is the end of the previous line,
3443 * so we know we have complete line starting
3444 * at (bp + 1). Prefix it onto any prior data
3445 * we collected for the line and process it.
3446 */
3447 strbuf_splice(&sb, 0, 0, bp + 1, endp - (bp + 1));
3448 scanp = bp;
3449 endp = bp + 1;
3450 ret = show_one_reflog_ent(&sb, fn, cb_data);
3451 strbuf_reset(&sb);
3452 if (ret)
3453 break;
3454 } else if (!pos) {
3455 /*
3456 * We are at the start of the buffer, and the
3457 * start of the file; there is no previous
3458 * line, and we have everything for this one.
3459 * Process it, and we can end the loop.
3460 */
3461 strbuf_splice(&sb, 0, 0, buf, endp - buf);
3462 ret = show_one_reflog_ent(&sb, fn, cb_data);
3463 strbuf_reset(&sb);
3464 break;
3465 }
3466
3467 if (bp == buf) {
3468 /*
3469 * We are at the start of the buffer, and there
3470 * is more file to read backwards. Which means
3471 * we are in the middle of a line. Note that we
3472 * may get here even if *bp was a newline; that
3473 * just means we are at the exact end of the
3474 * previous line, rather than some spot in the
3475 * middle.
3476 *
3477 * Save away what we have to be combined with
3478 * the data from the next read.
3479 */
3480 strbuf_splice(&sb, 0, 0, buf, endp - buf);
3481 break;
3482 }
3483 }
3484
3485 }
3486 if (!ret && sb.len)
3487 die("BUG: reverse reflog parser had leftover data");
3488
3489 fclose(logfp);
3490 strbuf_release(&sb);
3491 return ret;
3492 }
3493
3494 int for_each_reflog_ent(const char *refname, each_reflog_ent_fn fn, void *cb_data)
3495 {
3496 FILE *logfp;
3497 struct strbuf sb = STRBUF_INIT;
3498 int ret = 0;
3499
3500 logfp = fopen(git_path("logs/%s", refname), "r");
3501 if (!logfp)
3502 return -1;
3503
3504 while (!ret && !strbuf_getwholeline(&sb, logfp, '\n'))
3505 ret = show_one_reflog_ent(&sb, fn, cb_data);
3506 fclose(logfp);
3507 strbuf_release(&sb);
3508 return ret;
3509 }
3510 /*
3511 * Call fn for each reflog in the namespace indicated by name. name
3512 * must be empty or end with '/'. Name will be used as a scratch
3513 * space, but its contents will be restored before return.
3514 */
3515 static int do_for_each_reflog(struct strbuf *name, each_ref_fn fn, void *cb_data)
3516 {
3517 DIR *d = opendir(git_path("logs/%s", name->buf));
3518 int retval = 0;
3519 struct dirent *de;
3520 int oldlen = name->len;
3521
3522 if (!d)
3523 return name->len ? errno : 0;
3524
3525 while ((de = readdir(d)) != NULL) {
3526 struct stat st;
3527
3528 if (de->d_name[0] == '.')
3529 continue;
3530 if (ends_with(de->d_name, ".lock"))
3531 continue;
3532 strbuf_addstr(name, de->d_name);
3533 if (stat(git_path("logs/%s", name->buf), &st) < 0) {
3534 ; /* silently ignore */
3535 } else {
3536 if (S_ISDIR(st.st_mode)) {
3537 strbuf_addch(name, '/');
3538 retval = do_for_each_reflog(name, fn, cb_data);
3539 } else {
3540 unsigned char sha1[20];
3541 if (read_ref_full(name->buf, 0, sha1, NULL))
3542 retval = error("bad ref for %s", name->buf);
3543 else
3544 retval = fn(name->buf, sha1, 0, cb_data);
3545 }
3546 if (retval)
3547 break;
3548 }
3549 strbuf_setlen(name, oldlen);
3550 }
3551 closedir(d);
3552 return retval;
3553 }
3554
3555 int for_each_reflog(each_ref_fn fn, void *cb_data)
3556 {
3557 int retval;
3558 struct strbuf name;
3559 strbuf_init(&name, PATH_MAX);
3560 retval = do_for_each_reflog(&name, fn, cb_data);
3561 strbuf_release(&name);
3562 return retval;
3563 }
3564
3565 /**
3566 * Information needed for a single ref update. Set new_sha1 to the
3567 * new value or to zero to delete the ref. To check the old value
3568 * while locking the ref, set have_old to 1 and set old_sha1 to the
3569 * value or to zero to ensure the ref does not exist before update.
3570 */
3571 struct ref_update {
3572 unsigned char new_sha1[20];
3573 unsigned char old_sha1[20];
3574 unsigned int flags; /* REF_NODEREF? */
3575 int have_old; /* 1 if old_sha1 is valid, 0 otherwise */
3576 struct ref_lock *lock;
3577 int type;
3578 char *msg;
3579 const char refname[FLEX_ARRAY];
3580 };
3581
3582 /*
3583 * Transaction states.
3584 * OPEN: The transaction is in a valid state and can accept new updates.
3585 * An OPEN transaction can be committed.
3586 * CLOSED: A closed transaction is no longer active and no other operations
3587 * than free can be used on it in this state.
3588 * A transaction can either become closed by successfully committing
3589 * an active transaction or if there is a failure while building
3590 * the transaction thus rendering it failed/inactive.
3591 */
3592 enum ref_transaction_state {
3593 REF_TRANSACTION_OPEN = 0,
3594 REF_TRANSACTION_CLOSED = 1
3595 };
3596
3597 /*
3598 * Data structure for holding a reference transaction, which can
3599 * consist of checks and updates to multiple references, carried out
3600 * as atomically as possible. This structure is opaque to callers.
3601 */
3602 struct ref_transaction {
3603 struct ref_update **updates;
3604 size_t alloc;
3605 size_t nr;
3606 enum ref_transaction_state state;
3607 };
3608
3609 struct ref_transaction *ref_transaction_begin(struct strbuf *err)
3610 {
3611 assert(err);
3612
3613 return xcalloc(1, sizeof(struct ref_transaction));
3614 }
3615
3616 void ref_transaction_free(struct ref_transaction *transaction)
3617 {
3618 int i;
3619
3620 if (!transaction)
3621 return;
3622
3623 for (i = 0; i < transaction->nr; i++) {
3624 free(transaction->updates[i]->msg);
3625 free(transaction->updates[i]);
3626 }
3627 free(transaction->updates);
3628 free(transaction);
3629 }
3630
3631 static struct ref_update *add_update(struct ref_transaction *transaction,
3632 const char *refname)
3633 {
3634 size_t len = strlen(refname);
3635 struct ref_update *update = xcalloc(1, sizeof(*update) + len + 1);
3636
3637 strcpy((char *)update->refname, refname);
3638 ALLOC_GROW(transaction->updates, transaction->nr + 1, transaction->alloc);
3639 transaction->updates[transaction->nr++] = update;
3640 return update;
3641 }
3642
3643 int ref_transaction_update(struct ref_transaction *transaction,
3644 const char *refname,
3645 const unsigned char *new_sha1,
3646 const unsigned char *old_sha1,
3647 unsigned int flags, int have_old, const char *msg,
3648 struct strbuf *err)
3649 {
3650 struct ref_update *update;
3651
3652 assert(err);
3653
3654 if (transaction->state != REF_TRANSACTION_OPEN)
3655 die("BUG: update called for transaction that is not open");
3656
3657 if (have_old && !old_sha1)
3658 die("BUG: have_old is true but old_sha1 is NULL");
3659
3660 if (!is_null_sha1(new_sha1) &&
3661 check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
3662 strbuf_addf(err, "refusing to update ref with bad name %s",
3663 refname);
3664 return -1;
3665 }
3666
3667 update = add_update(transaction, refname);
3668 hashcpy(update->new_sha1, new_sha1);
3669 update->flags = flags;
3670 update->have_old = have_old;
3671 if (have_old)
3672 hashcpy(update->old_sha1, old_sha1);
3673 if (msg)
3674 update->msg = xstrdup(msg);
3675 return 0;
3676 }
3677
3678 int ref_transaction_create(struct ref_transaction *transaction,
3679 const char *refname,
3680 const unsigned char *new_sha1,
3681 unsigned int flags, const char *msg,
3682 struct strbuf *err)
3683 {
3684 return ref_transaction_update(transaction, refname, new_sha1,
3685 null_sha1, flags, 1, msg, err);
3686 }
3687
3688 int ref_transaction_delete(struct ref_transaction *transaction,
3689 const char *refname,
3690 const unsigned char *old_sha1,
3691 unsigned int flags, int have_old, const char *msg,
3692 struct strbuf *err)
3693 {
3694 return ref_transaction_update(transaction, refname, null_sha1,
3695 old_sha1, flags, have_old, msg, err);
3696 }
3697
3698 int update_ref(const char *action, const char *refname,
3699 const unsigned char *sha1, const unsigned char *oldval,
3700 unsigned int flags, enum action_on_err onerr)
3701 {
3702 struct ref_transaction *t;
3703 struct strbuf err = STRBUF_INIT;
3704
3705 t = ref_transaction_begin(&err);
3706 if (!t ||
3707 ref_transaction_update(t, refname, sha1, oldval, flags,
3708 !!oldval, action, &err) ||
3709 ref_transaction_commit(t, &err)) {
3710 const char *str = "update_ref failed for ref '%s': %s";
3711
3712 ref_transaction_free(t);
3713 switch (onerr) {
3714 case UPDATE_REFS_MSG_ON_ERR:
3715 error(str, refname, err.buf);
3716 break;
3717 case UPDATE_REFS_DIE_ON_ERR:
3718 die(str, refname, err.buf);
3719 break;
3720 case UPDATE_REFS_QUIET_ON_ERR:
3721 break;
3722 }
3723 strbuf_release(&err);
3724 return 1;
3725 }
3726 strbuf_release(&err);
3727 ref_transaction_free(t);
3728 return 0;
3729 }
3730
3731 static int ref_update_compare(const void *r1, const void *r2)
3732 {
3733 const struct ref_update * const *u1 = r1;
3734 const struct ref_update * const *u2 = r2;
3735 return strcmp((*u1)->refname, (*u2)->refname);
3736 }
3737
3738 static int ref_update_reject_duplicates(struct ref_update **updates, int n,
3739 struct strbuf *err)
3740 {
3741 int i;
3742
3743 assert(err);
3744
3745 for (i = 1; i < n; i++)
3746 if (!strcmp(updates[i - 1]->refname, updates[i]->refname)) {
3747 strbuf_addf(err,
3748 "Multiple updates for ref '%s' not allowed.",
3749 updates[i]->refname);
3750 return 1;
3751 }
3752 return 0;
3753 }
3754
3755 int ref_transaction_commit(struct ref_transaction *transaction,
3756 struct strbuf *err)
3757 {
3758 int ret = 0, i;
3759 int n = transaction->nr;
3760 struct ref_update **updates = transaction->updates;
3761 struct string_list refs_to_delete = STRING_LIST_INIT_NODUP;
3762 struct string_list_item *ref_to_delete;
3763
3764 assert(err);
3765
3766 if (transaction->state != REF_TRANSACTION_OPEN)
3767 die("BUG: commit called for transaction that is not open");
3768
3769 if (!n) {
3770 transaction->state = REF_TRANSACTION_CLOSED;
3771 return 0;
3772 }
3773
3774 /* Copy, sort, and reject duplicate refs */
3775 qsort(updates, n, sizeof(*updates), ref_update_compare);
3776 if (ref_update_reject_duplicates(updates, n, err)) {
3777 ret = TRANSACTION_GENERIC_ERROR;
3778 goto cleanup;
3779 }
3780
3781 /* Acquire all locks while verifying old values */
3782 for (i = 0; i < n; i++) {
3783 struct ref_update *update = updates[i];
3784 unsigned int flags = update->flags;
3785
3786 if (is_null_sha1(update->new_sha1))
3787 flags |= REF_DELETING;
3788 update->lock = lock_ref_sha1_basic(update->refname,
3789 (update->have_old ?
3790 update->old_sha1 :
3791 NULL),
3792 NULL,
3793 flags,
3794 &update->type);
3795 if (!update->lock) {
3796 ret = (errno == ENOTDIR)
3797 ? TRANSACTION_NAME_CONFLICT
3798 : TRANSACTION_GENERIC_ERROR;
3799 strbuf_addf(err, "Cannot lock the ref '%s'.",
3800 update->refname);
3801 goto cleanup;
3802 }
3803 }
3804
3805 /* Perform updates first so live commits remain referenced */
3806 for (i = 0; i < n; i++) {
3807 struct ref_update *update = updates[i];
3808
3809 if (!is_null_sha1(update->new_sha1)) {
3810 if (write_ref_sha1(update->lock, update->new_sha1,
3811 update->msg)) {
3812 update->lock = NULL; /* freed by write_ref_sha1 */
3813 strbuf_addf(err, "Cannot update the ref '%s'.",
3814 update->refname);
3815 ret = TRANSACTION_GENERIC_ERROR;
3816 goto cleanup;
3817 }
3818 update->lock = NULL; /* freed by write_ref_sha1 */
3819 }
3820 }
3821
3822 /* Perform deletes now that updates are safely completed */
3823 for (i = 0; i < n; i++) {
3824 struct ref_update *update = updates[i];
3825
3826 if (update->lock) {
3827 if (delete_ref_loose(update->lock, update->type, err)) {
3828 ret = TRANSACTION_GENERIC_ERROR;
3829 goto cleanup;
3830 }
3831
3832 if (!(update->flags & REF_ISPRUNING))
3833 string_list_append(&refs_to_delete,
3834 update->lock->ref_name);
3835 }
3836 }
3837
3838 if (repack_without_refs(&refs_to_delete, err)) {
3839 ret = TRANSACTION_GENERIC_ERROR;
3840 goto cleanup;
3841 }
3842 for_each_string_list_item(ref_to_delete, &refs_to_delete)
3843 unlink_or_warn(git_path("logs/%s", ref_to_delete->string));
3844 clear_loose_ref_cache(&ref_cache);
3845
3846 cleanup:
3847 transaction->state = REF_TRANSACTION_CLOSED;
3848
3849 for (i = 0; i < n; i++)
3850 if (updates[i]->lock)
3851 unlock_ref(updates[i]->lock);
3852 string_list_clear(&refs_to_delete, 0);
3853 return ret;
3854 }
3855
3856 char *shorten_unambiguous_ref(const char *refname, int strict)
3857 {
3858 int i;
3859 static char **scanf_fmts;
3860 static int nr_rules;
3861 char *short_name;
3862
3863 if (!nr_rules) {
3864 /*
3865 * Pre-generate scanf formats from ref_rev_parse_rules[].
3866 * Generate a format suitable for scanf from a
3867 * ref_rev_parse_rules rule by interpolating "%s" at the
3868 * location of the "%.*s".
3869 */
3870 size_t total_len = 0;
3871 size_t offset = 0;
3872
3873 /* the rule list is NULL terminated, count them first */
3874 for (nr_rules = 0; ref_rev_parse_rules[nr_rules]; nr_rules++)
3875 /* -2 for strlen("%.*s") - strlen("%s"); +1 for NUL */
3876 total_len += strlen(ref_rev_parse_rules[nr_rules]) - 2 + 1;
3877
3878 scanf_fmts = xmalloc(nr_rules * sizeof(char *) + total_len);
3879
3880 offset = 0;
3881 for (i = 0; i < nr_rules; i++) {
3882 assert(offset < total_len);
3883 scanf_fmts[i] = (char *)&scanf_fmts[nr_rules] + offset;
3884 offset += snprintf(scanf_fmts[i], total_len - offset,
3885 ref_rev_parse_rules[i], 2, "%s") + 1;
3886 }
3887 }
3888
3889 /* bail out if there are no rules */
3890 if (!nr_rules)
3891 return xstrdup(refname);
3892
3893 /* buffer for scanf result, at most refname must fit */
3894 short_name = xstrdup(refname);
3895
3896 /* skip first rule, it will always match */
3897 for (i = nr_rules - 1; i > 0 ; --i) {
3898 int j;
3899 int rules_to_fail = i;
3900 int short_name_len;
3901
3902 if (1 != sscanf(refname, scanf_fmts[i], short_name))
3903 continue;
3904
3905 short_name_len = strlen(short_name);
3906
3907 /*
3908 * in strict mode, all (except the matched one) rules
3909 * must fail to resolve to a valid non-ambiguous ref
3910 */
3911 if (strict)
3912 rules_to_fail = nr_rules;
3913
3914 /*
3915 * check if the short name resolves to a valid ref,
3916 * but use only rules prior to the matched one
3917 */
3918 for (j = 0; j < rules_to_fail; j++) {
3919 const char *rule = ref_rev_parse_rules[j];
3920 char refname[PATH_MAX];
3921
3922 /* skip matched rule */
3923 if (i == j)
3924 continue;
3925
3926 /*
3927 * the short name is ambiguous, if it resolves