packed-ref cache: forbid dot-components in refnames
[git/git.git] / refs.c
1 #include "cache.h"
2 #include "lockfile.h"
3 #include "refs.h"
4 #include "object.h"
5 #include "tag.h"
6 #include "dir.h"
7 #include "string-list.h"
8
9 /*
10 * How to handle various characters in refnames:
11 * 0: An acceptable character for refs
12 * 1: End-of-component
13 * 2: ., look for a preceding . to reject .. in refs
14 * 3: {, look for a preceding @ to reject @{ in refs
15 * 4: A bad character: ASCII control characters, "~", "^", ":" or SP
16 */
17 static unsigned char refname_disposition[256] = {
18 1, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
19 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
20 4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4, 0, 0, 0, 2, 1,
21 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4, 0, 0, 0, 0, 4,
22 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
23 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4, 4, 0, 4, 0,
24 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
25 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 3, 0, 0, 4, 4
26 };
27
28 /*
29 * Used as a flag to ref_transaction_delete when a loose ref is being
30 * pruned.
31 */
32 #define REF_ISPRUNING 0x0100
33 /*
34 * Try to read one refname component from the front of refname.
35 * Return the length of the component found, or -1 if the component is
36 * not legal. It is legal if it is something reasonable to have under
37 * ".git/refs/"; We do not like it if:
38 *
39 * - any path component of it begins with ".", or
40 * - it has double dots "..", or
41 * - it has ASCII control character, "~", "^", ":" or SP, anywhere, or
42 * - it ends with a "/".
43 * - it ends with ".lock"
44 * - it contains a "\" (backslash)
45 */
46 static int check_refname_component(const char *refname, int flags)
47 {
48 const char *cp;
49 char last = '\0';
50
51 for (cp = refname; ; cp++) {
52 int ch = *cp & 255;
53 unsigned char disp = refname_disposition[ch];
54 switch (disp) {
55 case 1:
56 goto out;
57 case 2:
58 if (last == '.')
59 return -1; /* Refname contains "..". */
60 break;
61 case 3:
62 if (last == '@')
63 return -1; /* Refname contains "@{". */
64 break;
65 case 4:
66 return -1;
67 }
68 last = ch;
69 }
70 out:
71 if (cp == refname)
72 return 0; /* Component has zero length. */
73 if (refname[0] == '.')
74 return -1; /* Component starts with '.'. */
75 if (cp - refname >= LOCK_SUFFIX_LEN &&
76 !memcmp(cp - LOCK_SUFFIX_LEN, LOCK_SUFFIX, LOCK_SUFFIX_LEN))
77 return -1; /* Refname ends with ".lock". */
78 return cp - refname;
79 }
80
81 int check_refname_format(const char *refname, int flags)
82 {
83 int component_len, component_count = 0;
84
85 if (!strcmp(refname, "@"))
86 /* Refname is a single character '@'. */
87 return -1;
88
89 while (1) {
90 /* We are at the start of a path component. */
91 component_len = check_refname_component(refname, flags);
92 if (component_len <= 0) {
93 if ((flags & REFNAME_REFSPEC_PATTERN) &&
94 refname[0] == '*' &&
95 (refname[1] == '\0' || refname[1] == '/')) {
96 /* Accept one wildcard as a full refname component. */
97 flags &= ~REFNAME_REFSPEC_PATTERN;
98 component_len = 1;
99 } else {
100 return -1;
101 }
102 }
103 component_count++;
104 if (refname[component_len] == '\0')
105 break;
106 /* Skip to next component. */
107 refname += component_len + 1;
108 }
109
110 if (refname[component_len - 1] == '.')
111 return -1; /* Refname ends with '.'. */
112 if (!(flags & REFNAME_ALLOW_ONELEVEL) && component_count < 2)
113 return -1; /* Refname has only one component. */
114 return 0;
115 }
116
117 struct ref_entry;
118
119 /*
120 * Information used (along with the information in ref_entry) to
121 * describe a single cached reference. This data structure only
122 * occurs embedded in a union in struct ref_entry, and only when
123 * (ref_entry->flag & REF_DIR) is zero.
124 */
125 struct ref_value {
126 /*
127 * The name of the object to which this reference resolves
128 * (which may be a tag object). If REF_ISBROKEN, this is
129 * null. If REF_ISSYMREF, then this is the name of the object
130 * referred to by the last reference in the symlink chain.
131 */
132 unsigned char sha1[20];
133
134 /*
135 * If REF_KNOWS_PEELED, then this field holds the peeled value
136 * of this reference, or null if the reference is known not to
137 * be peelable. See the documentation for peel_ref() for an
138 * exact definition of "peelable".
139 */
140 unsigned char peeled[20];
141 };
142
143 struct ref_cache;
144
145 /*
146 * Information used (along with the information in ref_entry) to
147 * describe a level in the hierarchy of references. This data
148 * structure only occurs embedded in a union in struct ref_entry, and
149 * only when (ref_entry.flag & REF_DIR) is set. In that case,
150 * (ref_entry.flag & REF_INCOMPLETE) determines whether the references
151 * in the directory have already been read:
152 *
153 * (ref_entry.flag & REF_INCOMPLETE) unset -- a directory of loose
154 * or packed references, already read.
155 *
156 * (ref_entry.flag & REF_INCOMPLETE) set -- a directory of loose
157 * references that hasn't been read yet (nor has any of its
158 * subdirectories).
159 *
160 * Entries within a directory are stored within a growable array of
161 * pointers to ref_entries (entries, nr, alloc). Entries 0 <= i <
162 * sorted are sorted by their component name in strcmp() order and the
163 * remaining entries are unsorted.
164 *
165 * Loose references are read lazily, one directory at a time. When a
166 * directory of loose references is read, then all of the references
167 * in that directory are stored, and REF_INCOMPLETE stubs are created
168 * for any subdirectories, but the subdirectories themselves are not
169 * read. The reading is triggered by get_ref_dir().
170 */
171 struct ref_dir {
172 int nr, alloc;
173
174 /*
175 * Entries with index 0 <= i < sorted are sorted by name. New
176 * entries are appended to the list unsorted, and are sorted
177 * only when required; thus we avoid the need to sort the list
178 * after the addition of every reference.
179 */
180 int sorted;
181
182 /* A pointer to the ref_cache that contains this ref_dir. */
183 struct ref_cache *ref_cache;
184
185 struct ref_entry **entries;
186 };
187
188 /*
189 * Bit values for ref_entry::flag. REF_ISSYMREF=0x01,
190 * REF_ISPACKED=0x02, and REF_ISBROKEN=0x04 are public values; see
191 * refs.h.
192 */
193
194 /*
195 * The field ref_entry->u.value.peeled of this value entry contains
196 * the correct peeled value for the reference, which might be
197 * null_sha1 if the reference is not a tag or if it is broken.
198 */
199 #define REF_KNOWS_PEELED 0x08
200
201 /* ref_entry represents a directory of references */
202 #define REF_DIR 0x10
203
204 /*
205 * Entry has not yet been read from disk (used only for REF_DIR
206 * entries representing loose references)
207 */
208 #define REF_INCOMPLETE 0x20
209
210 /*
211 * A ref_entry represents either a reference or a "subdirectory" of
212 * references.
213 *
214 * Each directory in the reference namespace is represented by a
215 * ref_entry with (flags & REF_DIR) set and containing a subdir member
216 * that holds the entries in that directory that have been read so
217 * far. If (flags & REF_INCOMPLETE) is set, then the directory and
218 * its subdirectories haven't been read yet. REF_INCOMPLETE is only
219 * used for loose reference directories.
220 *
221 * References are represented by a ref_entry with (flags & REF_DIR)
222 * unset and a value member that describes the reference's value. The
223 * flag member is at the ref_entry level, but it is also needed to
224 * interpret the contents of the value field (in other words, a
225 * ref_value object is not very much use without the enclosing
226 * ref_entry).
227 *
228 * Reference names cannot end with slash and directories' names are
229 * always stored with a trailing slash (except for the top-level
230 * directory, which is always denoted by ""). This has two nice
231 * consequences: (1) when the entries in each subdir are sorted
232 * lexicographically by name (as they usually are), the references in
233 * a whole tree can be generated in lexicographic order by traversing
234 * the tree in left-to-right, depth-first order; (2) the names of
235 * references and subdirectories cannot conflict, and therefore the
236 * presence of an empty subdirectory does not block the creation of a
237 * similarly-named reference. (The fact that reference names with the
238 * same leading components can conflict *with each other* is a
239 * separate issue that is regulated by is_refname_available().)
240 *
241 * Please note that the name field contains the fully-qualified
242 * reference (or subdirectory) name. Space could be saved by only
243 * storing the relative names. But that would require the full names
244 * to be generated on the fly when iterating in do_for_each_ref(), and
245 * would break callback functions, who have always been able to assume
246 * that the name strings that they are passed will not be freed during
247 * the iteration.
248 */
249 struct ref_entry {
250 unsigned char flag; /* ISSYMREF? ISPACKED? */
251 union {
252 struct ref_value value; /* if not (flags&REF_DIR) */
253 struct ref_dir subdir; /* if (flags&REF_DIR) */
254 } u;
255 /*
256 * The full name of the reference (e.g., "refs/heads/master")
257 * or the full name of the directory with a trailing slash
258 * (e.g., "refs/heads/"):
259 */
260 char name[FLEX_ARRAY];
261 };
262
263 static void read_loose_refs(const char *dirname, struct ref_dir *dir);
264
265 static struct ref_dir *get_ref_dir(struct ref_entry *entry)
266 {
267 struct ref_dir *dir;
268 assert(entry->flag & REF_DIR);
269 dir = &entry->u.subdir;
270 if (entry->flag & REF_INCOMPLETE) {
271 read_loose_refs(entry->name, dir);
272 entry->flag &= ~REF_INCOMPLETE;
273 }
274 return dir;
275 }
276
277 static struct ref_entry *create_ref_entry(const char *refname,
278 const unsigned char *sha1, int flag,
279 int check_name)
280 {
281 int len;
282 struct ref_entry *ref;
283
284 if (check_name &&
285 check_refname_format(refname, REFNAME_ALLOW_ONELEVEL))
286 die("Reference has invalid format: '%s'", refname);
287 len = strlen(refname) + 1;
288 ref = xmalloc(sizeof(struct ref_entry) + len);
289 hashcpy(ref->u.value.sha1, sha1);
290 hashclr(ref->u.value.peeled);
291 memcpy(ref->name, refname, len);
292 ref->flag = flag;
293 return ref;
294 }
295
296 static void clear_ref_dir(struct ref_dir *dir);
297
298 static void free_ref_entry(struct ref_entry *entry)
299 {
300 if (entry->flag & REF_DIR) {
301 /*
302 * Do not use get_ref_dir() here, as that might
303 * trigger the reading of loose refs.
304 */
305 clear_ref_dir(&entry->u.subdir);
306 }
307 free(entry);
308 }
309
310 /*
311 * Add a ref_entry to the end of dir (unsorted). Entry is always
312 * stored directly in dir; no recursion into subdirectories is
313 * done.
314 */
315 static void add_entry_to_dir(struct ref_dir *dir, struct ref_entry *entry)
316 {
317 ALLOC_GROW(dir->entries, dir->nr + 1, dir->alloc);
318 dir->entries[dir->nr++] = entry;
319 /* optimize for the case that entries are added in order */
320 if (dir->nr == 1 ||
321 (dir->nr == dir->sorted + 1 &&
322 strcmp(dir->entries[dir->nr - 2]->name,
323 dir->entries[dir->nr - 1]->name) < 0))
324 dir->sorted = dir->nr;
325 }
326
327 /*
328 * Clear and free all entries in dir, recursively.
329 */
330 static void clear_ref_dir(struct ref_dir *dir)
331 {
332 int i;
333 for (i = 0; i < dir->nr; i++)
334 free_ref_entry(dir->entries[i]);
335 free(dir->entries);
336 dir->sorted = dir->nr = dir->alloc = 0;
337 dir->entries = NULL;
338 }
339
340 /*
341 * Create a struct ref_entry object for the specified dirname.
342 * dirname is the name of the directory with a trailing slash (e.g.,
343 * "refs/heads/") or "" for the top-level directory.
344 */
345 static struct ref_entry *create_dir_entry(struct ref_cache *ref_cache,
346 const char *dirname, size_t len,
347 int incomplete)
348 {
349 struct ref_entry *direntry;
350 direntry = xcalloc(1, sizeof(struct ref_entry) + len + 1);
351 memcpy(direntry->name, dirname, len);
352 direntry->name[len] = '\0';
353 direntry->u.subdir.ref_cache = ref_cache;
354 direntry->flag = REF_DIR | (incomplete ? REF_INCOMPLETE : 0);
355 return direntry;
356 }
357
358 static int ref_entry_cmp(const void *a, const void *b)
359 {
360 struct ref_entry *one = *(struct ref_entry **)a;
361 struct ref_entry *two = *(struct ref_entry **)b;
362 return strcmp(one->name, two->name);
363 }
364
365 static void sort_ref_dir(struct ref_dir *dir);
366
367 struct string_slice {
368 size_t len;
369 const char *str;
370 };
371
372 static int ref_entry_cmp_sslice(const void *key_, const void *ent_)
373 {
374 const struct string_slice *key = key_;
375 const struct ref_entry *ent = *(const struct ref_entry * const *)ent_;
376 int cmp = strncmp(key->str, ent->name, key->len);
377 if (cmp)
378 return cmp;
379 return '\0' - (unsigned char)ent->name[key->len];
380 }
381
382 /*
383 * Return the index of the entry with the given refname from the
384 * ref_dir (non-recursively), sorting dir if necessary. Return -1 if
385 * no such entry is found. dir must already be complete.
386 */
387 static int search_ref_dir(struct ref_dir *dir, const char *refname, size_t len)
388 {
389 struct ref_entry **r;
390 struct string_slice key;
391
392 if (refname == NULL || !dir->nr)
393 return -1;
394
395 sort_ref_dir(dir);
396 key.len = len;
397 key.str = refname;
398 r = bsearch(&key, dir->entries, dir->nr, sizeof(*dir->entries),
399 ref_entry_cmp_sslice);
400
401 if (r == NULL)
402 return -1;
403
404 return r - dir->entries;
405 }
406
407 /*
408 * Search for a directory entry directly within dir (without
409 * recursing). Sort dir if necessary. subdirname must be a directory
410 * name (i.e., end in '/'). If mkdir is set, then create the
411 * directory if it is missing; otherwise, return NULL if the desired
412 * directory cannot be found. dir must already be complete.
413 */
414 static struct ref_dir *search_for_subdir(struct ref_dir *dir,
415 const char *subdirname, size_t len,
416 int mkdir)
417 {
418 int entry_index = search_ref_dir(dir, subdirname, len);
419 struct ref_entry *entry;
420 if (entry_index == -1) {
421 if (!mkdir)
422 return NULL;
423 /*
424 * Since dir is complete, the absence of a subdir
425 * means that the subdir really doesn't exist;
426 * therefore, create an empty record for it but mark
427 * the record complete.
428 */
429 entry = create_dir_entry(dir->ref_cache, subdirname, len, 0);
430 add_entry_to_dir(dir, entry);
431 } else {
432 entry = dir->entries[entry_index];
433 }
434 return get_ref_dir(entry);
435 }
436
437 /*
438 * If refname is a reference name, find the ref_dir within the dir
439 * tree that should hold refname. If refname is a directory name
440 * (i.e., ends in '/'), then return that ref_dir itself. dir must
441 * represent the top-level directory and must already be complete.
442 * Sort ref_dirs and recurse into subdirectories as necessary. If
443 * mkdir is set, then create any missing directories; otherwise,
444 * return NULL if the desired directory cannot be found.
445 */
446 static struct ref_dir *find_containing_dir(struct ref_dir *dir,
447 const char *refname, int mkdir)
448 {
449 const char *slash;
450 for (slash = strchr(refname, '/'); slash; slash = strchr(slash + 1, '/')) {
451 size_t dirnamelen = slash - refname + 1;
452 struct ref_dir *subdir;
453 subdir = search_for_subdir(dir, refname, dirnamelen, mkdir);
454 if (!subdir) {
455 dir = NULL;
456 break;
457 }
458 dir = subdir;
459 }
460
461 return dir;
462 }
463
464 /*
465 * Find the value entry with the given name in dir, sorting ref_dirs
466 * and recursing into subdirectories as necessary. If the name is not
467 * found or it corresponds to a directory entry, return NULL.
468 */
469 static struct ref_entry *find_ref(struct ref_dir *dir, const char *refname)
470 {
471 int entry_index;
472 struct ref_entry *entry;
473 dir = find_containing_dir(dir, refname, 0);
474 if (!dir)
475 return NULL;
476 entry_index = search_ref_dir(dir, refname, strlen(refname));
477 if (entry_index == -1)
478 return NULL;
479 entry = dir->entries[entry_index];
480 return (entry->flag & REF_DIR) ? NULL : entry;
481 }
482
483 /*
484 * Remove the entry with the given name from dir, recursing into
485 * subdirectories as necessary. If refname is the name of a directory
486 * (i.e., ends with '/'), then remove the directory and its contents.
487 * If the removal was successful, return the number of entries
488 * remaining in the directory entry that contained the deleted entry.
489 * If the name was not found, return -1. Please note that this
490 * function only deletes the entry from the cache; it does not delete
491 * it from the filesystem or ensure that other cache entries (which
492 * might be symbolic references to the removed entry) are updated.
493 * Nor does it remove any containing dir entries that might be made
494 * empty by the removal. dir must represent the top-level directory
495 * and must already be complete.
496 */
497 static int remove_entry(struct ref_dir *dir, const char *refname)
498 {
499 int refname_len = strlen(refname);
500 int entry_index;
501 struct ref_entry *entry;
502 int is_dir = refname[refname_len - 1] == '/';
503 if (is_dir) {
504 /*
505 * refname represents a reference directory. Remove
506 * the trailing slash; otherwise we will get the
507 * directory *representing* refname rather than the
508 * one *containing* it.
509 */
510 char *dirname = xmemdupz(refname, refname_len - 1);
511 dir = find_containing_dir(dir, dirname, 0);
512 free(dirname);
513 } else {
514 dir = find_containing_dir(dir, refname, 0);
515 }
516 if (!dir)
517 return -1;
518 entry_index = search_ref_dir(dir, refname, refname_len);
519 if (entry_index == -1)
520 return -1;
521 entry = dir->entries[entry_index];
522
523 memmove(&dir->entries[entry_index],
524 &dir->entries[entry_index + 1],
525 (dir->nr - entry_index - 1) * sizeof(*dir->entries)
526 );
527 dir->nr--;
528 if (dir->sorted > entry_index)
529 dir->sorted--;
530 free_ref_entry(entry);
531 return dir->nr;
532 }
533
534 /*
535 * Add a ref_entry to the ref_dir (unsorted), recursing into
536 * subdirectories as necessary. dir must represent the top-level
537 * directory. Return 0 on success.
538 */
539 static int add_ref(struct ref_dir *dir, struct ref_entry *ref)
540 {
541 dir = find_containing_dir(dir, ref->name, 1);
542 if (!dir)
543 return -1;
544 add_entry_to_dir(dir, ref);
545 return 0;
546 }
547
548 /*
549 * Emit a warning and return true iff ref1 and ref2 have the same name
550 * and the same sha1. Die if they have the same name but different
551 * sha1s.
552 */
553 static int is_dup_ref(const struct ref_entry *ref1, const struct ref_entry *ref2)
554 {
555 if (strcmp(ref1->name, ref2->name))
556 return 0;
557
558 /* Duplicate name; make sure that they don't conflict: */
559
560 if ((ref1->flag & REF_DIR) || (ref2->flag & REF_DIR))
561 /* This is impossible by construction */
562 die("Reference directory conflict: %s", ref1->name);
563
564 if (hashcmp(ref1->u.value.sha1, ref2->u.value.sha1))
565 die("Duplicated ref, and SHA1s don't match: %s", ref1->name);
566
567 warning("Duplicated ref: %s", ref1->name);
568 return 1;
569 }
570
571 /*
572 * Sort the entries in dir non-recursively (if they are not already
573 * sorted) and remove any duplicate entries.
574 */
575 static void sort_ref_dir(struct ref_dir *dir)
576 {
577 int i, j;
578 struct ref_entry *last = NULL;
579
580 /*
581 * This check also prevents passing a zero-length array to qsort(),
582 * which is a problem on some platforms.
583 */
584 if (dir->sorted == dir->nr)
585 return;
586
587 qsort(dir->entries, dir->nr, sizeof(*dir->entries), ref_entry_cmp);
588
589 /* Remove any duplicates: */
590 for (i = 0, j = 0; j < dir->nr; j++) {
591 struct ref_entry *entry = dir->entries[j];
592 if (last && is_dup_ref(last, entry))
593 free_ref_entry(entry);
594 else
595 last = dir->entries[i++] = entry;
596 }
597 dir->sorted = dir->nr = i;
598 }
599
600 /* Include broken references in a do_for_each_ref*() iteration: */
601 #define DO_FOR_EACH_INCLUDE_BROKEN 0x01
602
603 /*
604 * Return true iff the reference described by entry can be resolved to
605 * an object in the database. Emit a warning if the referred-to
606 * object does not exist.
607 */
608 static int ref_resolves_to_object(struct ref_entry *entry)
609 {
610 if (entry->flag & REF_ISBROKEN)
611 return 0;
612 if (!has_sha1_file(entry->u.value.sha1)) {
613 error("%s does not point to a valid object!", entry->name);
614 return 0;
615 }
616 return 1;
617 }
618
619 /*
620 * current_ref is a performance hack: when iterating over references
621 * using the for_each_ref*() functions, current_ref is set to the
622 * current reference's entry before calling the callback function. If
623 * the callback function calls peel_ref(), then peel_ref() first
624 * checks whether the reference to be peeled is the current reference
625 * (it usually is) and if so, returns that reference's peeled version
626 * if it is available. This avoids a refname lookup in a common case.
627 */
628 static struct ref_entry *current_ref;
629
630 typedef int each_ref_entry_fn(struct ref_entry *entry, void *cb_data);
631
632 struct ref_entry_cb {
633 const char *base;
634 int trim;
635 int flags;
636 each_ref_fn *fn;
637 void *cb_data;
638 };
639
640 /*
641 * Handle one reference in a do_for_each_ref*()-style iteration,
642 * calling an each_ref_fn for each entry.
643 */
644 static int do_one_ref(struct ref_entry *entry, void *cb_data)
645 {
646 struct ref_entry_cb *data = cb_data;
647 struct ref_entry *old_current_ref;
648 int retval;
649
650 if (!starts_with(entry->name, data->base))
651 return 0;
652
653 if (!(data->flags & DO_FOR_EACH_INCLUDE_BROKEN) &&
654 !ref_resolves_to_object(entry))
655 return 0;
656
657 /* Store the old value, in case this is a recursive call: */
658 old_current_ref = current_ref;
659 current_ref = entry;
660 retval = data->fn(entry->name + data->trim, entry->u.value.sha1,
661 entry->flag, data->cb_data);
662 current_ref = old_current_ref;
663 return retval;
664 }
665
666 /*
667 * Call fn for each reference in dir that has index in the range
668 * offset <= index < dir->nr. Recurse into subdirectories that are in
669 * that index range, sorting them before iterating. This function
670 * does not sort dir itself; it should be sorted beforehand. fn is
671 * called for all references, including broken ones.
672 */
673 static int do_for_each_entry_in_dir(struct ref_dir *dir, int offset,
674 each_ref_entry_fn fn, void *cb_data)
675 {
676 int i;
677 assert(dir->sorted == dir->nr);
678 for (i = offset; i < dir->nr; i++) {
679 struct ref_entry *entry = dir->entries[i];
680 int retval;
681 if (entry->flag & REF_DIR) {
682 struct ref_dir *subdir = get_ref_dir(entry);
683 sort_ref_dir(subdir);
684 retval = do_for_each_entry_in_dir(subdir, 0, fn, cb_data);
685 } else {
686 retval = fn(entry, cb_data);
687 }
688 if (retval)
689 return retval;
690 }
691 return 0;
692 }
693
694 /*
695 * Call fn for each reference in the union of dir1 and dir2, in order
696 * by refname. Recurse into subdirectories. If a value entry appears
697 * in both dir1 and dir2, then only process the version that is in
698 * dir2. The input dirs must already be sorted, but subdirs will be
699 * sorted as needed. fn is called for all references, including
700 * broken ones.
701 */
702 static int do_for_each_entry_in_dirs(struct ref_dir *dir1,
703 struct ref_dir *dir2,
704 each_ref_entry_fn fn, void *cb_data)
705 {
706 int retval;
707 int i1 = 0, i2 = 0;
708
709 assert(dir1->sorted == dir1->nr);
710 assert(dir2->sorted == dir2->nr);
711 while (1) {
712 struct ref_entry *e1, *e2;
713 int cmp;
714 if (i1 == dir1->nr) {
715 return do_for_each_entry_in_dir(dir2, i2, fn, cb_data);
716 }
717 if (i2 == dir2->nr) {
718 return do_for_each_entry_in_dir(dir1, i1, fn, cb_data);
719 }
720 e1 = dir1->entries[i1];
721 e2 = dir2->entries[i2];
722 cmp = strcmp(e1->name, e2->name);
723 if (cmp == 0) {
724 if ((e1->flag & REF_DIR) && (e2->flag & REF_DIR)) {
725 /* Both are directories; descend them in parallel. */
726 struct ref_dir *subdir1 = get_ref_dir(e1);
727 struct ref_dir *subdir2 = get_ref_dir(e2);
728 sort_ref_dir(subdir1);
729 sort_ref_dir(subdir2);
730 retval = do_for_each_entry_in_dirs(
731 subdir1, subdir2, fn, cb_data);
732 i1++;
733 i2++;
734 } else if (!(e1->flag & REF_DIR) && !(e2->flag & REF_DIR)) {
735 /* Both are references; ignore the one from dir1. */
736 retval = fn(e2, cb_data);
737 i1++;
738 i2++;
739 } else {
740 die("conflict between reference and directory: %s",
741 e1->name);
742 }
743 } else {
744 struct ref_entry *e;
745 if (cmp < 0) {
746 e = e1;
747 i1++;
748 } else {
749 e = e2;
750 i2++;
751 }
752 if (e->flag & REF_DIR) {
753 struct ref_dir *subdir = get_ref_dir(e);
754 sort_ref_dir(subdir);
755 retval = do_for_each_entry_in_dir(
756 subdir, 0, fn, cb_data);
757 } else {
758 retval = fn(e, cb_data);
759 }
760 }
761 if (retval)
762 return retval;
763 }
764 }
765
766 /*
767 * Load all of the refs from the dir into our in-memory cache. The hard work
768 * of loading loose refs is done by get_ref_dir(), so we just need to recurse
769 * through all of the sub-directories. We do not even need to care about
770 * sorting, as traversal order does not matter to us.
771 */
772 static void prime_ref_dir(struct ref_dir *dir)
773 {
774 int i;
775 for (i = 0; i < dir->nr; i++) {
776 struct ref_entry *entry = dir->entries[i];
777 if (entry->flag & REF_DIR)
778 prime_ref_dir(get_ref_dir(entry));
779 }
780 }
781
782 static int entry_matches(struct ref_entry *entry, const struct string_list *list)
783 {
784 return list && string_list_has_string(list, entry->name);
785 }
786
787 struct nonmatching_ref_data {
788 const struct string_list *skip;
789 struct ref_entry *found;
790 };
791
792 static int nonmatching_ref_fn(struct ref_entry *entry, void *vdata)
793 {
794 struct nonmatching_ref_data *data = vdata;
795
796 if (entry_matches(entry, data->skip))
797 return 0;
798
799 data->found = entry;
800 return 1;
801 }
802
803 static void report_refname_conflict(struct ref_entry *entry,
804 const char *refname)
805 {
806 error("'%s' exists; cannot create '%s'", entry->name, refname);
807 }
808
809 /*
810 * Return true iff a reference named refname could be created without
811 * conflicting with the name of an existing reference in dir. If
812 * skip is non-NULL, ignore potential conflicts with refs in skip
813 * (e.g., because they are scheduled for deletion in the same
814 * operation).
815 *
816 * Two reference names conflict if one of them exactly matches the
817 * leading components of the other; e.g., "foo/bar" conflicts with
818 * both "foo" and with "foo/bar/baz" but not with "foo/bar" or
819 * "foo/barbados".
820 *
821 * skip must be sorted.
822 */
823 static int is_refname_available(const char *refname,
824 const struct string_list *skip,
825 struct ref_dir *dir)
826 {
827 const char *slash;
828 size_t len;
829 int pos;
830 char *dirname;
831
832 for (slash = strchr(refname, '/'); slash; slash = strchr(slash + 1, '/')) {
833 /*
834 * We are still at a leading dir of the refname; we are
835 * looking for a conflict with a leaf entry.
836 *
837 * If we find one, we still must make sure it is
838 * not in "skip".
839 */
840 pos = search_ref_dir(dir, refname, slash - refname);
841 if (pos >= 0) {
842 struct ref_entry *entry = dir->entries[pos];
843 if (entry_matches(entry, skip))
844 return 1;
845 report_refname_conflict(entry, refname);
846 return 0;
847 }
848
849
850 /*
851 * Otherwise, we can try to continue our search with
852 * the next component; if we come up empty, we know
853 * there is nothing under this whole prefix.
854 */
855 pos = search_ref_dir(dir, refname, slash + 1 - refname);
856 if (pos < 0)
857 return 1;
858
859 dir = get_ref_dir(dir->entries[pos]);
860 }
861
862 /*
863 * We are at the leaf of our refname; we want to
864 * make sure there are no directories which match it.
865 */
866 len = strlen(refname);
867 dirname = xmallocz(len + 1);
868 sprintf(dirname, "%s/", refname);
869 pos = search_ref_dir(dir, dirname, len + 1);
870 free(dirname);
871
872 if (pos >= 0) {
873 /*
874 * We found a directory named "refname". It is a
875 * problem iff it contains any ref that is not
876 * in "skip".
877 */
878 struct ref_entry *entry = dir->entries[pos];
879 struct ref_dir *dir = get_ref_dir(entry);
880 struct nonmatching_ref_data data;
881
882 data.skip = skip;
883 sort_ref_dir(dir);
884 if (!do_for_each_entry_in_dir(dir, 0, nonmatching_ref_fn, &data))
885 return 1;
886
887 report_refname_conflict(data.found, refname);
888 return 0;
889 }
890
891 /*
892 * There is no point in searching for another leaf
893 * node which matches it; such an entry would be the
894 * ref we are looking for, not a conflict.
895 */
896 return 1;
897 }
898
899 struct packed_ref_cache {
900 struct ref_entry *root;
901
902 /*
903 * Count of references to the data structure in this instance,
904 * including the pointer from ref_cache::packed if any. The
905 * data will not be freed as long as the reference count is
906 * nonzero.
907 */
908 unsigned int referrers;
909
910 /*
911 * Iff the packed-refs file associated with this instance is
912 * currently locked for writing, this points at the associated
913 * lock (which is owned by somebody else). The referrer count
914 * is also incremented when the file is locked and decremented
915 * when it is unlocked.
916 */
917 struct lock_file *lock;
918
919 /* The metadata from when this packed-refs cache was read */
920 struct stat_validity validity;
921 };
922
923 /*
924 * Future: need to be in "struct repository"
925 * when doing a full libification.
926 */
927 static struct ref_cache {
928 struct ref_cache *next;
929 struct ref_entry *loose;
930 struct packed_ref_cache *packed;
931 /*
932 * The submodule name, or "" for the main repo. We allocate
933 * length 1 rather than FLEX_ARRAY so that the main ref_cache
934 * is initialized correctly.
935 */
936 char name[1];
937 } ref_cache, *submodule_ref_caches;
938
939 /* Lock used for the main packed-refs file: */
940 static struct lock_file packlock;
941
942 /*
943 * Increment the reference count of *packed_refs.
944 */
945 static void acquire_packed_ref_cache(struct packed_ref_cache *packed_refs)
946 {
947 packed_refs->referrers++;
948 }
949
950 /*
951 * Decrease the reference count of *packed_refs. If it goes to zero,
952 * free *packed_refs and return true; otherwise return false.
953 */
954 static int release_packed_ref_cache(struct packed_ref_cache *packed_refs)
955 {
956 if (!--packed_refs->referrers) {
957 free_ref_entry(packed_refs->root);
958 stat_validity_clear(&packed_refs->validity);
959 free(packed_refs);
960 return 1;
961 } else {
962 return 0;
963 }
964 }
965
966 static void clear_packed_ref_cache(struct ref_cache *refs)
967 {
968 if (refs->packed) {
969 struct packed_ref_cache *packed_refs = refs->packed;
970
971 if (packed_refs->lock)
972 die("internal error: packed-ref cache cleared while locked");
973 refs->packed = NULL;
974 release_packed_ref_cache(packed_refs);
975 }
976 }
977
978 static void clear_loose_ref_cache(struct ref_cache *refs)
979 {
980 if (refs->loose) {
981 free_ref_entry(refs->loose);
982 refs->loose = NULL;
983 }
984 }
985
986 static struct ref_cache *create_ref_cache(const char *submodule)
987 {
988 int len;
989 struct ref_cache *refs;
990 if (!submodule)
991 submodule = "";
992 len = strlen(submodule) + 1;
993 refs = xcalloc(1, sizeof(struct ref_cache) + len);
994 memcpy(refs->name, submodule, len);
995 return refs;
996 }
997
998 /*
999 * Return a pointer to a ref_cache for the specified submodule. For
1000 * the main repository, use submodule==NULL. The returned structure
1001 * will be allocated and initialized but not necessarily populated; it
1002 * should not be freed.
1003 */
1004 static struct ref_cache *get_ref_cache(const char *submodule)
1005 {
1006 struct ref_cache *refs;
1007
1008 if (!submodule || !*submodule)
1009 return &ref_cache;
1010
1011 for (refs = submodule_ref_caches; refs; refs = refs->next)
1012 if (!strcmp(submodule, refs->name))
1013 return refs;
1014
1015 refs = create_ref_cache(submodule);
1016 refs->next = submodule_ref_caches;
1017 submodule_ref_caches = refs;
1018 return refs;
1019 }
1020
1021 /* The length of a peeled reference line in packed-refs, including EOL: */
1022 #define PEELED_LINE_LENGTH 42
1023
1024 /*
1025 * The packed-refs header line that we write out. Perhaps other
1026 * traits will be added later. The trailing space is required.
1027 */
1028 static const char PACKED_REFS_HEADER[] =
1029 "# pack-refs with: peeled fully-peeled \n";
1030
1031 /*
1032 * Parse one line from a packed-refs file. Write the SHA1 to sha1.
1033 * Return a pointer to the refname within the line (null-terminated),
1034 * or NULL if there was a problem.
1035 */
1036 static const char *parse_ref_line(char *line, unsigned char *sha1)
1037 {
1038 /*
1039 * 42: the answer to everything.
1040 *
1041 * In this case, it happens to be the answer to
1042 * 40 (length of sha1 hex representation)
1043 * +1 (space in between hex and name)
1044 * +1 (newline at the end of the line)
1045 */
1046 int len = strlen(line) - 42;
1047
1048 if (len <= 0)
1049 return NULL;
1050 if (get_sha1_hex(line, sha1) < 0)
1051 return NULL;
1052 if (!isspace(line[40]))
1053 return NULL;
1054 line += 41;
1055 if (isspace(*line))
1056 return NULL;
1057 if (line[len] != '\n')
1058 return NULL;
1059 line[len] = 0;
1060
1061 return line;
1062 }
1063
1064 /*
1065 * Read f, which is a packed-refs file, into dir.
1066 *
1067 * A comment line of the form "# pack-refs with: " may contain zero or
1068 * more traits. We interpret the traits as follows:
1069 *
1070 * No traits:
1071 *
1072 * Probably no references are peeled. But if the file contains a
1073 * peeled value for a reference, we will use it.
1074 *
1075 * peeled:
1076 *
1077 * References under "refs/tags/", if they *can* be peeled, *are*
1078 * peeled in this file. References outside of "refs/tags/" are
1079 * probably not peeled even if they could have been, but if we find
1080 * a peeled value for such a reference we will use it.
1081 *
1082 * fully-peeled:
1083 *
1084 * All references in the file that can be peeled are peeled.
1085 * Inversely (and this is more important), any references in the
1086 * file for which no peeled value is recorded is not peelable. This
1087 * trait should typically be written alongside "peeled" for
1088 * compatibility with older clients, but we do not require it
1089 * (i.e., "peeled" is a no-op if "fully-peeled" is set).
1090 */
1091 static void read_packed_refs(FILE *f, struct ref_dir *dir)
1092 {
1093 struct ref_entry *last = NULL;
1094 char refline[PATH_MAX];
1095 enum { PEELED_NONE, PEELED_TAGS, PEELED_FULLY } peeled = PEELED_NONE;
1096
1097 while (fgets(refline, sizeof(refline), f)) {
1098 unsigned char sha1[20];
1099 const char *refname;
1100 static const char header[] = "# pack-refs with:";
1101
1102 if (!strncmp(refline, header, sizeof(header)-1)) {
1103 const char *traits = refline + sizeof(header) - 1;
1104 if (strstr(traits, " fully-peeled "))
1105 peeled = PEELED_FULLY;
1106 else if (strstr(traits, " peeled "))
1107 peeled = PEELED_TAGS;
1108 /* perhaps other traits later as well */
1109 continue;
1110 }
1111
1112 refname = parse_ref_line(refline, sha1);
1113 if (refname) {
1114 last = create_ref_entry(refname, sha1, REF_ISPACKED, 1);
1115 if (peeled == PEELED_FULLY ||
1116 (peeled == PEELED_TAGS && starts_with(refname, "refs/tags/")))
1117 last->flag |= REF_KNOWS_PEELED;
1118 add_ref(dir, last);
1119 continue;
1120 }
1121 if (last &&
1122 refline[0] == '^' &&
1123 strlen(refline) == PEELED_LINE_LENGTH &&
1124 refline[PEELED_LINE_LENGTH - 1] == '\n' &&
1125 !get_sha1_hex(refline + 1, sha1)) {
1126 hashcpy(last->u.value.peeled, sha1);
1127 /*
1128 * Regardless of what the file header said,
1129 * we definitely know the value of *this*
1130 * reference:
1131 */
1132 last->flag |= REF_KNOWS_PEELED;
1133 }
1134 }
1135 }
1136
1137 /*
1138 * Get the packed_ref_cache for the specified ref_cache, creating it
1139 * if necessary.
1140 */
1141 static struct packed_ref_cache *get_packed_ref_cache(struct ref_cache *refs)
1142 {
1143 const char *packed_refs_file;
1144
1145 if (*refs->name)
1146 packed_refs_file = git_path_submodule(refs->name, "packed-refs");
1147 else
1148 packed_refs_file = git_path("packed-refs");
1149
1150 if (refs->packed &&
1151 !stat_validity_check(&refs->packed->validity, packed_refs_file))
1152 clear_packed_ref_cache(refs);
1153
1154 if (!refs->packed) {
1155 FILE *f;
1156
1157 refs->packed = xcalloc(1, sizeof(*refs->packed));
1158 acquire_packed_ref_cache(refs->packed);
1159 refs->packed->root = create_dir_entry(refs, "", 0, 0);
1160 f = fopen(packed_refs_file, "r");
1161 if (f) {
1162 stat_validity_update(&refs->packed->validity, fileno(f));
1163 read_packed_refs(f, get_ref_dir(refs->packed->root));
1164 fclose(f);
1165 }
1166 }
1167 return refs->packed;
1168 }
1169
1170 static struct ref_dir *get_packed_ref_dir(struct packed_ref_cache *packed_ref_cache)
1171 {
1172 return get_ref_dir(packed_ref_cache->root);
1173 }
1174
1175 static struct ref_dir *get_packed_refs(struct ref_cache *refs)
1176 {
1177 return get_packed_ref_dir(get_packed_ref_cache(refs));
1178 }
1179
1180 void add_packed_ref(const char *refname, const unsigned char *sha1)
1181 {
1182 struct packed_ref_cache *packed_ref_cache =
1183 get_packed_ref_cache(&ref_cache);
1184
1185 if (!packed_ref_cache->lock)
1186 die("internal error: packed refs not locked");
1187 add_ref(get_packed_ref_dir(packed_ref_cache),
1188 create_ref_entry(refname, sha1, REF_ISPACKED, 1));
1189 }
1190
1191 /*
1192 * Read the loose references from the namespace dirname into dir
1193 * (without recursing). dirname must end with '/'. dir must be the
1194 * directory entry corresponding to dirname.
1195 */
1196 static void read_loose_refs(const char *dirname, struct ref_dir *dir)
1197 {
1198 struct ref_cache *refs = dir->ref_cache;
1199 DIR *d;
1200 const char *path;
1201 struct dirent *de;
1202 int dirnamelen = strlen(dirname);
1203 struct strbuf refname;
1204
1205 if (*refs->name)
1206 path = git_path_submodule(refs->name, "%s", dirname);
1207 else
1208 path = git_path("%s", dirname);
1209
1210 d = opendir(path);
1211 if (!d)
1212 return;
1213
1214 strbuf_init(&refname, dirnamelen + 257);
1215 strbuf_add(&refname, dirname, dirnamelen);
1216
1217 while ((de = readdir(d)) != NULL) {
1218 unsigned char sha1[20];
1219 struct stat st;
1220 int flag;
1221 const char *refdir;
1222
1223 if (de->d_name[0] == '.')
1224 continue;
1225 if (ends_with(de->d_name, ".lock"))
1226 continue;
1227 strbuf_addstr(&refname, de->d_name);
1228 refdir = *refs->name
1229 ? git_path_submodule(refs->name, "%s", refname.buf)
1230 : git_path("%s", refname.buf);
1231 if (stat(refdir, &st) < 0) {
1232 ; /* silently ignore */
1233 } else if (S_ISDIR(st.st_mode)) {
1234 strbuf_addch(&refname, '/');
1235 add_entry_to_dir(dir,
1236 create_dir_entry(refs, refname.buf,
1237 refname.len, 1));
1238 } else {
1239 if (*refs->name) {
1240 hashclr(sha1);
1241 flag = 0;
1242 if (resolve_gitlink_ref(refs->name, refname.buf, sha1) < 0) {
1243 hashclr(sha1);
1244 flag |= REF_ISBROKEN;
1245 }
1246 } else if (read_ref_full(refname.buf,
1247 RESOLVE_REF_READING,
1248 sha1, &flag)) {
1249 hashclr(sha1);
1250 flag |= REF_ISBROKEN;
1251 }
1252 add_entry_to_dir(dir,
1253 create_ref_entry(refname.buf, sha1, flag, 1));
1254 }
1255 strbuf_setlen(&refname, dirnamelen);
1256 }
1257 strbuf_release(&refname);
1258 closedir(d);
1259 }
1260
1261 static struct ref_dir *get_loose_refs(struct ref_cache *refs)
1262 {
1263 if (!refs->loose) {
1264 /*
1265 * Mark the top-level directory complete because we
1266 * are about to read the only subdirectory that can
1267 * hold references:
1268 */
1269 refs->loose = create_dir_entry(refs, "", 0, 0);
1270 /*
1271 * Create an incomplete entry for "refs/":
1272 */
1273 add_entry_to_dir(get_ref_dir(refs->loose),
1274 create_dir_entry(refs, "refs/", 5, 1));
1275 }
1276 return get_ref_dir(refs->loose);
1277 }
1278
1279 /* We allow "recursive" symbolic refs. Only within reason, though */
1280 #define MAXDEPTH 5
1281 #define MAXREFLEN (1024)
1282
1283 /*
1284 * Called by resolve_gitlink_ref_recursive() after it failed to read
1285 * from the loose refs in ref_cache refs. Find <refname> in the
1286 * packed-refs file for the submodule.
1287 */
1288 static int resolve_gitlink_packed_ref(struct ref_cache *refs,
1289 const char *refname, unsigned char *sha1)
1290 {
1291 struct ref_entry *ref;
1292 struct ref_dir *dir = get_packed_refs(refs);
1293
1294 ref = find_ref(dir, refname);
1295 if (ref == NULL)
1296 return -1;
1297
1298 hashcpy(sha1, ref->u.value.sha1);
1299 return 0;
1300 }
1301
1302 static int resolve_gitlink_ref_recursive(struct ref_cache *refs,
1303 const char *refname, unsigned char *sha1,
1304 int recursion)
1305 {
1306 int fd, len;
1307 char buffer[128], *p;
1308 char *path;
1309
1310 if (recursion > MAXDEPTH || strlen(refname) > MAXREFLEN)
1311 return -1;
1312 path = *refs->name
1313 ? git_path_submodule(refs->name, "%s", refname)
1314 : git_path("%s", refname);
1315 fd = open(path, O_RDONLY);
1316 if (fd < 0)
1317 return resolve_gitlink_packed_ref(refs, refname, sha1);
1318
1319 len = read(fd, buffer, sizeof(buffer)-1);
1320 close(fd);
1321 if (len < 0)
1322 return -1;
1323 while (len && isspace(buffer[len-1]))
1324 len--;
1325 buffer[len] = 0;
1326
1327 /* Was it a detached head or an old-fashioned symlink? */
1328 if (!get_sha1_hex(buffer, sha1))
1329 return 0;
1330
1331 /* Symref? */
1332 if (strncmp(buffer, "ref:", 4))
1333 return -1;
1334 p = buffer + 4;
1335 while (isspace(*p))
1336 p++;
1337
1338 return resolve_gitlink_ref_recursive(refs, p, sha1, recursion+1);
1339 }
1340
1341 int resolve_gitlink_ref(const char *path, const char *refname, unsigned char *sha1)
1342 {
1343 int len = strlen(path), retval;
1344 char *submodule;
1345 struct ref_cache *refs;
1346
1347 while (len && path[len-1] == '/')
1348 len--;
1349 if (!len)
1350 return -1;
1351 submodule = xstrndup(path, len);
1352 refs = get_ref_cache(submodule);
1353 free(submodule);
1354
1355 retval = resolve_gitlink_ref_recursive(refs, refname, sha1, 0);
1356 return retval;
1357 }
1358
1359 /*
1360 * Return the ref_entry for the given refname from the packed
1361 * references. If it does not exist, return NULL.
1362 */
1363 static struct ref_entry *get_packed_ref(const char *refname)
1364 {
1365 return find_ref(get_packed_refs(&ref_cache), refname);
1366 }
1367
1368 /*
1369 * A loose ref file doesn't exist; check for a packed ref. The
1370 * options are forwarded from resolve_safe_unsafe().
1371 */
1372 static const char *handle_missing_loose_ref(const char *refname,
1373 int resolve_flags,
1374 unsigned char *sha1,
1375 int *flags)
1376 {
1377 struct ref_entry *entry;
1378
1379 /*
1380 * The loose reference file does not exist; check for a packed
1381 * reference.
1382 */
1383 entry = get_packed_ref(refname);
1384 if (entry) {
1385 hashcpy(sha1, entry->u.value.sha1);
1386 if (flags)
1387 *flags |= REF_ISPACKED;
1388 return refname;
1389 }
1390 /* The reference is not a packed reference, either. */
1391 if (resolve_flags & RESOLVE_REF_READING) {
1392 return NULL;
1393 } else {
1394 hashclr(sha1);
1395 return refname;
1396 }
1397 }
1398
1399 /* This function needs to return a meaningful errno on failure */
1400 const char *resolve_ref_unsafe(const char *refname, int resolve_flags, unsigned char *sha1, int *flags)
1401 {
1402 int depth = MAXDEPTH;
1403 ssize_t len;
1404 char buffer[256];
1405 static char refname_buffer[256];
1406
1407 if (flags)
1408 *flags = 0;
1409
1410 if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
1411 errno = EINVAL;
1412 return NULL;
1413 }
1414 for (;;) {
1415 char path[PATH_MAX];
1416 struct stat st;
1417 char *buf;
1418 int fd;
1419
1420 if (--depth < 0) {
1421 errno = ELOOP;
1422 return NULL;
1423 }
1424
1425 git_snpath(path, sizeof(path), "%s", refname);
1426
1427 /*
1428 * We might have to loop back here to avoid a race
1429 * condition: first we lstat() the file, then we try
1430 * to read it as a link or as a file. But if somebody
1431 * changes the type of the file (file <-> directory
1432 * <-> symlink) between the lstat() and reading, then
1433 * we don't want to report that as an error but rather
1434 * try again starting with the lstat().
1435 */
1436 stat_ref:
1437 if (lstat(path, &st) < 0) {
1438 if (errno == ENOENT)
1439 return handle_missing_loose_ref(refname,
1440 resolve_flags, sha1, flags);
1441 else
1442 return NULL;
1443 }
1444
1445 /* Follow "normalized" - ie "refs/.." symlinks by hand */
1446 if (S_ISLNK(st.st_mode)) {
1447 len = readlink(path, buffer, sizeof(buffer)-1);
1448 if (len < 0) {
1449 if (errno == ENOENT || errno == EINVAL)
1450 /* inconsistent with lstat; retry */
1451 goto stat_ref;
1452 else
1453 return NULL;
1454 }
1455 buffer[len] = 0;
1456 if (starts_with(buffer, "refs/") &&
1457 !check_refname_format(buffer, 0)) {
1458 strcpy(refname_buffer, buffer);
1459 refname = refname_buffer;
1460 if (flags)
1461 *flags |= REF_ISSYMREF;
1462 if (resolve_flags & RESOLVE_REF_NO_RECURSE) {
1463 hashclr(sha1);
1464 return refname;
1465 }
1466 continue;
1467 }
1468 }
1469
1470 /* Is it a directory? */
1471 if (S_ISDIR(st.st_mode)) {
1472 errno = EISDIR;
1473 return NULL;
1474 }
1475
1476 /*
1477 * Anything else, just open it and try to use it as
1478 * a ref
1479 */
1480 fd = open(path, O_RDONLY);
1481 if (fd < 0) {
1482 if (errno == ENOENT)
1483 /* inconsistent with lstat; retry */
1484 goto stat_ref;
1485 else
1486 return NULL;
1487 }
1488 len = read_in_full(fd, buffer, sizeof(buffer)-1);
1489 if (len < 0) {
1490 int save_errno = errno;
1491 close(fd);
1492 errno = save_errno;
1493 return NULL;
1494 }
1495 close(fd);
1496 while (len && isspace(buffer[len-1]))
1497 len--;
1498 buffer[len] = '\0';
1499
1500 /*
1501 * Is it a symbolic ref?
1502 */
1503 if (!starts_with(buffer, "ref:")) {
1504 /*
1505 * Please note that FETCH_HEAD has a second
1506 * line containing other data.
1507 */
1508 if (get_sha1_hex(buffer, sha1) ||
1509 (buffer[40] != '\0' && !isspace(buffer[40]))) {
1510 if (flags)
1511 *flags |= REF_ISBROKEN;
1512 errno = EINVAL;
1513 return NULL;
1514 }
1515 return refname;
1516 }
1517 if (flags)
1518 *flags |= REF_ISSYMREF;
1519 buf = buffer + 4;
1520 while (isspace(*buf))
1521 buf++;
1522 refname = strcpy(refname_buffer, buf);
1523 if (resolve_flags & RESOLVE_REF_NO_RECURSE) {
1524 hashclr(sha1);
1525 return refname;
1526 }
1527 if (check_refname_format(buf, REFNAME_ALLOW_ONELEVEL)) {
1528 if (flags)
1529 *flags |= REF_ISBROKEN;
1530 errno = EINVAL;
1531 return NULL;
1532 }
1533 }
1534 }
1535
1536 char *resolve_refdup(const char *ref, int resolve_flags, unsigned char *sha1, int *flags)
1537 {
1538 const char *ret = resolve_ref_unsafe(ref, resolve_flags, sha1, flags);
1539 return ret ? xstrdup(ret) : NULL;
1540 }
1541
1542 /* The argument to filter_refs */
1543 struct ref_filter {
1544 const char *pattern;
1545 each_ref_fn *fn;
1546 void *cb_data;
1547 };
1548
1549 int read_ref_full(const char *refname, int resolve_flags, unsigned char *sha1, int *flags)
1550 {
1551 if (resolve_ref_unsafe(refname, resolve_flags, sha1, flags))
1552 return 0;
1553 return -1;
1554 }
1555
1556 int read_ref(const char *refname, unsigned char *sha1)
1557 {
1558 return read_ref_full(refname, RESOLVE_REF_READING, sha1, NULL);
1559 }
1560
1561 int ref_exists(const char *refname)
1562 {
1563 unsigned char sha1[20];
1564 return !!resolve_ref_unsafe(refname, RESOLVE_REF_READING, sha1, NULL);
1565 }
1566
1567 static int filter_refs(const char *refname, const unsigned char *sha1, int flags,
1568 void *data)
1569 {
1570 struct ref_filter *filter = (struct ref_filter *)data;
1571 if (wildmatch(filter->pattern, refname, 0, NULL))
1572 return 0;
1573 return filter->fn(refname, sha1, flags, filter->cb_data);
1574 }
1575
1576 enum peel_status {
1577 /* object was peeled successfully: */
1578 PEEL_PEELED = 0,
1579
1580 /*
1581 * object cannot be peeled because the named object (or an
1582 * object referred to by a tag in the peel chain), does not
1583 * exist.
1584 */
1585 PEEL_INVALID = -1,
1586
1587 /* object cannot be peeled because it is not a tag: */
1588 PEEL_NON_TAG = -2,
1589
1590 /* ref_entry contains no peeled value because it is a symref: */
1591 PEEL_IS_SYMREF = -3,
1592
1593 /*
1594 * ref_entry cannot be peeled because it is broken (i.e., the
1595 * symbolic reference cannot even be resolved to an object
1596 * name):
1597 */
1598 PEEL_BROKEN = -4
1599 };
1600
1601 /*
1602 * Peel the named object; i.e., if the object is a tag, resolve the
1603 * tag recursively until a non-tag is found. If successful, store the
1604 * result to sha1 and return PEEL_PEELED. If the object is not a tag
1605 * or is not valid, return PEEL_NON_TAG or PEEL_INVALID, respectively,
1606 * and leave sha1 unchanged.
1607 */
1608 static enum peel_status peel_object(const unsigned char *name, unsigned char *sha1)
1609 {
1610 struct object *o = lookup_unknown_object(name);
1611
1612 if (o->type == OBJ_NONE) {
1613 int type = sha1_object_info(name, NULL);
1614 if (type < 0 || !object_as_type(o, type, 0))
1615 return PEEL_INVALID;
1616 }
1617
1618 if (o->type != OBJ_TAG)
1619 return PEEL_NON_TAG;
1620
1621 o = deref_tag_noverify(o);
1622 if (!o)
1623 return PEEL_INVALID;
1624
1625 hashcpy(sha1, o->sha1);
1626 return PEEL_PEELED;
1627 }
1628
1629 /*
1630 * Peel the entry (if possible) and return its new peel_status. If
1631 * repeel is true, re-peel the entry even if there is an old peeled
1632 * value that is already stored in it.
1633 *
1634 * It is OK to call this function with a packed reference entry that
1635 * might be stale and might even refer to an object that has since
1636 * been garbage-collected. In such a case, if the entry has
1637 * REF_KNOWS_PEELED then leave the status unchanged and return
1638 * PEEL_PEELED or PEEL_NON_TAG; otherwise, return PEEL_INVALID.
1639 */
1640 static enum peel_status peel_entry(struct ref_entry *entry, int repeel)
1641 {
1642 enum peel_status status;
1643
1644 if (entry->flag & REF_KNOWS_PEELED) {
1645 if (repeel) {
1646 entry->flag &= ~REF_KNOWS_PEELED;
1647 hashclr(entry->u.value.peeled);
1648 } else {
1649 return is_null_sha1(entry->u.value.peeled) ?
1650 PEEL_NON_TAG : PEEL_PEELED;
1651 }
1652 }
1653 if (entry->flag & REF_ISBROKEN)
1654 return PEEL_BROKEN;
1655 if (entry->flag & REF_ISSYMREF)
1656 return PEEL_IS_SYMREF;
1657
1658 status = peel_object(entry->u.value.sha1, entry->u.value.peeled);
1659 if (status == PEEL_PEELED || status == PEEL_NON_TAG)
1660 entry->flag |= REF_KNOWS_PEELED;
1661 return status;
1662 }
1663
1664 int peel_ref(const char *refname, unsigned char *sha1)
1665 {
1666 int flag;
1667 unsigned char base[20];
1668
1669 if (current_ref && (current_ref->name == refname
1670 || !strcmp(current_ref->name, refname))) {
1671 if (peel_entry(current_ref, 0))
1672 return -1;
1673 hashcpy(sha1, current_ref->u.value.peeled);
1674 return 0;
1675 }
1676
1677 if (read_ref_full(refname, RESOLVE_REF_READING, base, &flag))
1678 return -1;
1679
1680 /*
1681 * If the reference is packed, read its ref_entry from the
1682 * cache in the hope that we already know its peeled value.
1683 * We only try this optimization on packed references because
1684 * (a) forcing the filling of the loose reference cache could
1685 * be expensive and (b) loose references anyway usually do not
1686 * have REF_KNOWS_PEELED.
1687 */
1688 if (flag & REF_ISPACKED) {
1689 struct ref_entry *r = get_packed_ref(refname);
1690 if (r) {
1691 if (peel_entry(r, 0))
1692 return -1;
1693 hashcpy(sha1, r->u.value.peeled);
1694 return 0;
1695 }
1696 }
1697
1698 return peel_object(base, sha1);
1699 }
1700
1701 struct warn_if_dangling_data {
1702 FILE *fp;
1703 const char *refname;
1704 const struct string_list *refnames;
1705 const char *msg_fmt;
1706 };
1707
1708 static int warn_if_dangling_symref(const char *refname, const unsigned char *sha1,
1709 int flags, void *cb_data)
1710 {
1711 struct warn_if_dangling_data *d = cb_data;
1712 const char *resolves_to;
1713 unsigned char junk[20];
1714
1715 if (!(flags & REF_ISSYMREF))
1716 return 0;
1717
1718 resolves_to = resolve_ref_unsafe(refname, 0, junk, NULL);
1719 if (!resolves_to
1720 || (d->refname
1721 ? strcmp(resolves_to, d->refname)
1722 : !string_list_has_string(d->refnames, resolves_to))) {
1723 return 0;
1724 }
1725
1726 fprintf(d->fp, d->msg_fmt, refname);
1727 fputc('\n', d->fp);
1728 return 0;
1729 }
1730
1731 void warn_dangling_symref(FILE *fp, const char *msg_fmt, const char *refname)
1732 {
1733 struct warn_if_dangling_data data;
1734
1735 data.fp = fp;
1736 data.refname = refname;
1737 data.refnames = NULL;
1738 data.msg_fmt = msg_fmt;
1739 for_each_rawref(warn_if_dangling_symref, &data);
1740 }
1741
1742 void warn_dangling_symrefs(FILE *fp, const char *msg_fmt, const struct string_list *refnames)
1743 {
1744 struct warn_if_dangling_data data;
1745
1746 data.fp = fp;
1747 data.refname = NULL;
1748 data.refnames = refnames;
1749 data.msg_fmt = msg_fmt;
1750 for_each_rawref(warn_if_dangling_symref, &data);
1751 }
1752
1753 /*
1754 * Call fn for each reference in the specified ref_cache, omitting
1755 * references not in the containing_dir of base. fn is called for all
1756 * references, including broken ones. If fn ever returns a non-zero
1757 * value, stop the iteration and return that value; otherwise, return
1758 * 0.
1759 */
1760 static int do_for_each_entry(struct ref_cache *refs, const char *base,
1761 each_ref_entry_fn fn, void *cb_data)
1762 {
1763 struct packed_ref_cache *packed_ref_cache;
1764 struct ref_dir *loose_dir;
1765 struct ref_dir *packed_dir;
1766 int retval = 0;
1767
1768 /*
1769 * We must make sure that all loose refs are read before accessing the
1770 * packed-refs file; this avoids a race condition in which loose refs
1771 * are migrated to the packed-refs file by a simultaneous process, but
1772 * our in-memory view is from before the migration. get_packed_ref_cache()
1773 * takes care of making sure our view is up to date with what is on
1774 * disk.
1775 */
1776 loose_dir = get_loose_refs(refs);
1777 if (base && *base) {
1778 loose_dir = find_containing_dir(loose_dir, base, 0);
1779 }
1780 if (loose_dir)
1781 prime_ref_dir(loose_dir);
1782
1783 packed_ref_cache = get_packed_ref_cache(refs);
1784 acquire_packed_ref_cache(packed_ref_cache);
1785 packed_dir = get_packed_ref_dir(packed_ref_cache);
1786 if (base && *base) {
1787 packed_dir = find_containing_dir(packed_dir, base, 0);
1788 }
1789
1790 if (packed_dir && loose_dir) {
1791 sort_ref_dir(packed_dir);
1792 sort_ref_dir(loose_dir);
1793 retval = do_for_each_entry_in_dirs(
1794 packed_dir, loose_dir, fn, cb_data);
1795 } else if (packed_dir) {
1796 sort_ref_dir(packed_dir);
1797 retval = do_for_each_entry_in_dir(
1798 packed_dir, 0, fn, cb_data);
1799 } else if (loose_dir) {
1800 sort_ref_dir(loose_dir);
1801 retval = do_for_each_entry_in_dir(
1802 loose_dir, 0, fn, cb_data);
1803 }
1804
1805 release_packed_ref_cache(packed_ref_cache);
1806 return retval;
1807 }
1808
1809 /*
1810 * Call fn for each reference in the specified ref_cache for which the
1811 * refname begins with base. If trim is non-zero, then trim that many
1812 * characters off the beginning of each refname before passing the
1813 * refname to fn. flags can be DO_FOR_EACH_INCLUDE_BROKEN to include
1814 * broken references in the iteration. If fn ever returns a non-zero
1815 * value, stop the iteration and return that value; otherwise, return
1816 * 0.
1817 */
1818 static int do_for_each_ref(struct ref_cache *refs, const char *base,
1819 each_ref_fn fn, int trim, int flags, void *cb_data)
1820 {
1821 struct ref_entry_cb data;
1822 data.base = base;
1823 data.trim = trim;
1824 data.flags = flags;
1825 data.fn = fn;
1826 data.cb_data = cb_data;
1827
1828 return do_for_each_entry(refs, base, do_one_ref, &data);
1829 }
1830
1831 static int do_head_ref(const char *submodule, each_ref_fn fn, void *cb_data)
1832 {
1833 unsigned char sha1[20];
1834 int flag;
1835
1836 if (submodule) {
1837 if (resolve_gitlink_ref(submodule, "HEAD", sha1) == 0)
1838 return fn("HEAD", sha1, 0, cb_data);
1839
1840 return 0;
1841 }
1842
1843 if (!read_ref_full("HEAD", RESOLVE_REF_READING, sha1, &flag))
1844 return fn("HEAD", sha1, flag, cb_data);
1845
1846 return 0;
1847 }
1848
1849 int head_ref(each_ref_fn fn, void *cb_data)
1850 {
1851 return do_head_ref(NULL, fn, cb_data);
1852 }
1853
1854 int head_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
1855 {
1856 return do_head_ref(submodule, fn, cb_data);
1857 }
1858
1859 int for_each_ref(each_ref_fn fn, void *cb_data)
1860 {
1861 return do_for_each_ref(&ref_cache, "", fn, 0, 0, cb_data);
1862 }
1863
1864 int for_each_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
1865 {
1866 return do_for_each_ref(get_ref_cache(submodule), "", fn, 0, 0, cb_data);
1867 }
1868
1869 int for_each_ref_in(const char *prefix, each_ref_fn fn, void *cb_data)
1870 {
1871 return do_for_each_ref(&ref_cache, prefix, fn, strlen(prefix), 0, cb_data);
1872 }
1873
1874 int for_each_ref_in_submodule(const char *submodule, const char *prefix,
1875 each_ref_fn fn, void *cb_data)
1876 {
1877 return do_for_each_ref(get_ref_cache(submodule), prefix, fn, strlen(prefix), 0, cb_data);
1878 }
1879
1880 int for_each_tag_ref(each_ref_fn fn, void *cb_data)
1881 {
1882 return for_each_ref_in("refs/tags/", fn, cb_data);
1883 }
1884
1885 int for_each_tag_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
1886 {
1887 return for_each_ref_in_submodule(submodule, "refs/tags/", fn, cb_data);
1888 }
1889
1890 int for_each_branch_ref(each_ref_fn fn, void *cb_data)
1891 {
1892 return for_each_ref_in("refs/heads/", fn, cb_data);
1893 }
1894
1895 int for_each_branch_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
1896 {
1897 return for_each_ref_in_submodule(submodule, "refs/heads/", fn, cb_data);
1898 }
1899
1900 int for_each_remote_ref(each_ref_fn fn, void *cb_data)
1901 {
1902 return for_each_ref_in("refs/remotes/", fn, cb_data);
1903 }
1904
1905 int for_each_remote_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
1906 {
1907 return for_each_ref_in_submodule(submodule, "refs/remotes/", fn, cb_data);
1908 }
1909
1910 int for_each_replace_ref(each_ref_fn fn, void *cb_data)
1911 {
1912 return do_for_each_ref(&ref_cache, "refs/replace/", fn, 13, 0, cb_data);
1913 }
1914
1915 int head_ref_namespaced(each_ref_fn fn, void *cb_data)
1916 {
1917 struct strbuf buf = STRBUF_INIT;
1918 int ret = 0;
1919 unsigned char sha1[20];
1920 int flag;
1921
1922 strbuf_addf(&buf, "%sHEAD", get_git_namespace());
1923 if (!read_ref_full(buf.buf, RESOLVE_REF_READING, sha1, &flag))
1924 ret = fn(buf.buf, sha1, flag, cb_data);
1925 strbuf_release(&buf);
1926
1927 return ret;
1928 }
1929
1930 int for_each_namespaced_ref(each_ref_fn fn, void *cb_data)
1931 {
1932 struct strbuf buf = STRBUF_INIT;
1933 int ret;
1934 strbuf_addf(&buf, "%srefs/", get_git_namespace());
1935 ret = do_for_each_ref(&ref_cache, buf.buf, fn, 0, 0, cb_data);
1936 strbuf_release(&buf);
1937 return ret;
1938 }
1939
1940 int for_each_glob_ref_in(each_ref_fn fn, const char *pattern,
1941 const char *prefix, void *cb_data)
1942 {
1943 struct strbuf real_pattern = STRBUF_INIT;
1944 struct ref_filter filter;
1945 int ret;
1946
1947 if (!prefix && !starts_with(pattern, "refs/"))
1948 strbuf_addstr(&real_pattern, "refs/");
1949 else if (prefix)
1950 strbuf_addstr(&real_pattern, prefix);
1951 strbuf_addstr(&real_pattern, pattern);
1952
1953 if (!has_glob_specials(pattern)) {
1954 /* Append implied '/' '*' if not present. */
1955 if (real_pattern.buf[real_pattern.len - 1] != '/')
1956 strbuf_addch(&real_pattern, '/');
1957 /* No need to check for '*', there is none. */
1958 strbuf_addch(&real_pattern, '*');
1959 }
1960
1961 filter.pattern = real_pattern.buf;
1962 filter.fn = fn;
1963 filter.cb_data = cb_data;
1964 ret = for_each_ref(filter_refs, &filter);
1965
1966 strbuf_release(&real_pattern);
1967 return ret;
1968 }
1969
1970 int for_each_glob_ref(each_ref_fn fn, const char *pattern, void *cb_data)
1971 {
1972 return for_each_glob_ref_in(fn, pattern, NULL, cb_data);
1973 }
1974
1975 int for_each_rawref(each_ref_fn fn, void *cb_data)
1976 {
1977 return do_for_each_ref(&ref_cache, "", fn, 0,
1978 DO_FOR_EACH_INCLUDE_BROKEN, cb_data);
1979 }
1980
1981 const char *prettify_refname(const char *name)
1982 {
1983 return name + (
1984 starts_with(name, "refs/heads/") ? 11 :
1985 starts_with(name, "refs/tags/") ? 10 :
1986 starts_with(name, "refs/remotes/") ? 13 :
1987 0);
1988 }
1989
1990 static const char *ref_rev_parse_rules[] = {
1991 "%.*s",
1992 "refs/%.*s",
1993 "refs/tags/%.*s",
1994 "refs/heads/%.*s",
1995 "refs/remotes/%.*s",
1996 "refs/remotes/%.*s/HEAD",
1997 NULL
1998 };
1999
2000 int refname_match(const char *abbrev_name, const char *full_name)
2001 {
2002 const char **p;
2003 const int abbrev_name_len = strlen(abbrev_name);
2004
2005 for (p = ref_rev_parse_rules; *p; p++) {
2006 if (!strcmp(full_name, mkpath(*p, abbrev_name_len, abbrev_name))) {
2007 return 1;
2008 }
2009 }
2010
2011 return 0;
2012 }
2013
2014 /* This function should make sure errno is meaningful on error */
2015 static struct ref_lock *verify_lock(struct ref_lock *lock,
2016 const unsigned char *old_sha1, int mustexist)
2017 {
2018 if (read_ref_full(lock->ref_name,
2019 mustexist ? RESOLVE_REF_READING : 0,
2020 lock->old_sha1, NULL)) {
2021 int save_errno = errno;
2022 error("Can't verify ref %s", lock->ref_name);
2023 unlock_ref(lock);
2024 errno = save_errno;
2025 return NULL;
2026 }
2027 if (hashcmp(lock->old_sha1, old_sha1)) {
2028 error("Ref %s is at %s but expected %s", lock->ref_name,
2029 sha1_to_hex(lock->old_sha1), sha1_to_hex(old_sha1));
2030 unlock_ref(lock);
2031 errno = EBUSY;
2032 return NULL;
2033 }
2034 return lock;
2035 }
2036
2037 static int remove_empty_directories(const char *file)
2038 {
2039 /* we want to create a file but there is a directory there;
2040 * if that is an empty directory (or a directory that contains
2041 * only empty directories), remove them.
2042 */
2043 struct strbuf path;
2044 int result, save_errno;
2045
2046 strbuf_init(&path, 20);
2047 strbuf_addstr(&path, file);
2048
2049 result = remove_dir_recursively(&path, REMOVE_DIR_EMPTY_ONLY);
2050 save_errno = errno;
2051
2052 strbuf_release(&path);
2053 errno = save_errno;
2054
2055 return result;
2056 }
2057
2058 /*
2059 * *string and *len will only be substituted, and *string returned (for
2060 * later free()ing) if the string passed in is a magic short-hand form
2061 * to name a branch.
2062 */
2063 static char *substitute_branch_name(const char **string, int *len)
2064 {
2065 struct strbuf buf = STRBUF_INIT;
2066 int ret = interpret_branch_name(*string, *len, &buf);
2067
2068 if (ret == *len) {
2069 size_t size;
2070 *string = strbuf_detach(&buf, &size);
2071 *len = size;
2072 return (char *)*string;
2073 }
2074
2075 return NULL;
2076 }
2077
2078 int dwim_ref(const char *str, int len, unsigned char *sha1, char **ref)
2079 {
2080 char *last_branch = substitute_branch_name(&str, &len);
2081 const char **p, *r;
2082 int refs_found = 0;
2083
2084 *ref = NULL;
2085 for (p = ref_rev_parse_rules; *p; p++) {
2086 char fullref[PATH_MAX];
2087 unsigned char sha1_from_ref[20];
2088 unsigned char *this_result;
2089 int flag;
2090
2091 this_result = refs_found ? sha1_from_ref : sha1;
2092 mksnpath(fullref, sizeof(fullref), *p, len, str);
2093 r = resolve_ref_unsafe(fullref, RESOLVE_REF_READING,
2094 this_result, &flag);
2095 if (r) {
2096 if (!refs_found++)
2097 *ref = xstrdup(r);
2098 if (!warn_ambiguous_refs)
2099 break;
2100 } else if ((flag & REF_ISSYMREF) && strcmp(fullref, "HEAD")) {
2101 warning("ignoring dangling symref %s.", fullref);
2102 } else if ((flag & REF_ISBROKEN) && strchr(fullref, '/')) {
2103 warning("ignoring broken ref %s.", fullref);
2104 }
2105 }
2106 free(last_branch);
2107 return refs_found;
2108 }
2109
2110 int dwim_log(const char *str, int len, unsigned char *sha1, char **log)
2111 {
2112 char *last_branch = substitute_branch_name(&str, &len);
2113 const char **p;
2114 int logs_found = 0;
2115
2116 *log = NULL;
2117 for (p = ref_rev_parse_rules; *p; p++) {
2118 unsigned char hash[20];
2119 char path[PATH_MAX];
2120 const char *ref, *it;
2121
2122 mksnpath(path, sizeof(path), *p, len, str);
2123 ref = resolve_ref_unsafe(path, RESOLVE_REF_READING,
2124 hash, NULL);
2125 if (!ref)
2126 continue;
2127 if (reflog_exists(path))
2128 it = path;
2129 else if (strcmp(ref, path) && reflog_exists(ref))
2130 it = ref;
2131 else
2132 continue;
2133 if (!logs_found++) {
2134 *log = xstrdup(it);
2135 hashcpy(sha1, hash);
2136 }
2137 if (!warn_ambiguous_refs)
2138 break;
2139 }
2140 free(last_branch);
2141 return logs_found;
2142 }
2143
2144 /*
2145 * Locks a ref returning the lock on success and NULL on failure.
2146 * On failure errno is set to something meaningful.
2147 */
2148 static struct ref_lock *lock_ref_sha1_basic(const char *refname,
2149 const unsigned char *old_sha1,
2150 const struct string_list *skip,
2151 int flags, int *type_p)
2152 {
2153 char *ref_file;
2154 const char *orig_refname = refname;
2155 struct ref_lock *lock;
2156 int last_errno = 0;
2157 int type, lflags;
2158 int mustexist = (old_sha1 && !is_null_sha1(old_sha1));
2159 int resolve_flags = 0;
2160 int missing = 0;
2161 int attempts_remaining = 3;
2162
2163 if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
2164 errno = EINVAL;
2165 return NULL;
2166 }
2167
2168 lock = xcalloc(1, sizeof(struct ref_lock));
2169 lock->lock_fd = -1;
2170
2171 if (mustexist)
2172 resolve_flags |= RESOLVE_REF_READING;
2173 if (flags & REF_NODEREF && flags & REF_DELETING)
2174 resolve_flags |= RESOLVE_REF_NO_RECURSE;
2175
2176 refname = resolve_ref_unsafe(refname, resolve_flags,
2177 lock->old_sha1, &type);
2178 if (!refname && errno == EISDIR) {
2179 /* we are trying to lock foo but we used to
2180 * have foo/bar which now does not exist;
2181 * it is normal for the empty directory 'foo'
2182 * to remain.
2183 */
2184 ref_file = git_path("%s", orig_refname);
2185 if (remove_empty_directories(ref_file)) {
2186 last_errno = errno;
2187 error("there are still refs under '%s'", orig_refname);
2188 goto error_return;
2189 }
2190 refname = resolve_ref_unsafe(orig_refname, resolve_flags,
2191 lock->old_sha1, &type);
2192 }
2193 if (type_p)
2194 *type_p = type;
2195 if (!refname) {
2196 last_errno = errno;
2197 error("unable to resolve reference %s: %s",
2198 orig_refname, strerror(errno));
2199 goto error_return;
2200 }
2201 missing = is_null_sha1(lock->old_sha1);
2202 /* When the ref did not exist and we are creating it,
2203 * make sure there is no existing ref that is packed
2204 * whose name begins with our refname, nor a ref whose
2205 * name is a proper prefix of our refname.
2206 */
2207 if (missing &&
2208 !is_refname_available(refname, skip, get_packed_refs(&ref_cache))) {
2209 last_errno = ENOTDIR;
2210 goto error_return;
2211 }
2212
2213 lock->lk = xcalloc(1, sizeof(struct lock_file));
2214
2215 lflags = 0;
2216 if (flags & REF_NODEREF) {
2217 refname = orig_refname;
2218 lflags |= LOCK_NO_DEREF;
2219 }
2220 lock->ref_name = xstrdup(refname);
2221 lock->orig_ref_name = xstrdup(orig_refname);
2222 ref_file = git_path("%s", refname);
2223 if (missing)
2224 lock->force_write = 1;
2225 if ((flags & REF_NODEREF) && (type & REF_ISSYMREF))
2226 lock->force_write = 1;
2227
2228 retry:
2229 switch (safe_create_leading_directories(ref_file)) {
2230 case SCLD_OK:
2231 break; /* success */
2232 case SCLD_VANISHED:
2233 if (--attempts_remaining > 0)
2234 goto retry;
2235 /* fall through */
2236 default:
2237 last_errno = errno;
2238 error("unable to create directory for %s", ref_file);
2239 goto error_return;
2240 }
2241
2242 lock->lock_fd = hold_lock_file_for_update(lock->lk, ref_file, lflags);
2243 if (lock->lock_fd < 0) {
2244 if (errno == ENOENT && --attempts_remaining > 0)
2245 /*
2246 * Maybe somebody just deleted one of the
2247 * directories leading to ref_file. Try
2248 * again:
2249 */
2250 goto retry;
2251 else
2252 unable_to_lock_die(ref_file, errno);
2253 }
2254 return old_sha1 ? verify_lock(lock, old_sha1, mustexist) : lock;
2255
2256 error_return:
2257 unlock_ref(lock);
2258 errno = last_errno;
2259 return NULL;
2260 }
2261
2262 struct ref_lock *lock_any_ref_for_update(const char *refname,
2263 const unsigned char *old_sha1,
2264 int flags, int *type_p)
2265 {
2266 return lock_ref_sha1_basic(refname, old_sha1, NULL, flags, type_p);
2267 }
2268
2269 /*
2270 * Write an entry to the packed-refs file for the specified refname.
2271 * If peeled is non-NULL, write it as the entry's peeled value.
2272 */
2273 static void write_packed_entry(FILE *fh, char *refname, unsigned char *sha1,
2274 unsigned char *peeled)
2275 {
2276 fprintf_or_die(fh, "%s %s\n", sha1_to_hex(sha1), refname);
2277 if (peeled)
2278 fprintf_or_die(fh, "^%s\n", sha1_to_hex(peeled));
2279 }
2280
2281 /*
2282 * An each_ref_entry_fn that writes the entry to a packed-refs file.
2283 */
2284 static int write_packed_entry_fn(struct ref_entry *entry, void *cb_data)
2285 {
2286 enum peel_status peel_status = peel_entry(entry, 0);
2287
2288 if (peel_status != PEEL_PEELED && peel_status != PEEL_NON_TAG)
2289 error("internal error: %s is not a valid packed reference!",
2290 entry->name);
2291 write_packed_entry(cb_data, entry->name, entry->u.value.sha1,
2292 peel_status == PEEL_PEELED ?
2293 entry->u.value.peeled : NULL);
2294 return 0;
2295 }
2296
2297 /* This should return a meaningful errno on failure */
2298 int lock_packed_refs(int flags)
2299 {
2300 struct packed_ref_cache *packed_ref_cache;
2301
2302 if (hold_lock_file_for_update(&packlock, git_path("packed-refs"), flags) < 0)
2303 return -1;
2304 /*
2305 * Get the current packed-refs while holding the lock. If the
2306 * packed-refs file has been modified since we last read it,
2307 * this will automatically invalidate the cache and re-read
2308 * the packed-refs file.
2309 */
2310 packed_ref_cache = get_packed_ref_cache(&ref_cache);
2311 packed_ref_cache->lock = &packlock;
2312 /* Increment the reference count to prevent it from being freed: */
2313 acquire_packed_ref_cache(packed_ref_cache);
2314 return 0;
2315 }
2316
2317 /*
2318 * Commit the packed refs changes.
2319 * On error we must make sure that errno contains a meaningful value.
2320 */
2321 int commit_packed_refs(void)
2322 {
2323 struct packed_ref_cache *packed_ref_cache =
2324 get_packed_ref_cache(&ref_cache);
2325 int error = 0;
2326 int save_errno = 0;
2327 FILE *out;
2328
2329 if (!packed_ref_cache->lock)
2330 die("internal error: packed-refs not locked");
2331
2332 out = fdopen_lock_file(packed_ref_cache->lock, "w");
2333 if (!out)
2334 die_errno("unable to fdopen packed-refs descriptor");
2335
2336 fprintf_or_die(out, "%s", PACKED_REFS_HEADER);
2337 do_for_each_entry_in_dir(get_packed_ref_dir(packed_ref_cache),
2338 0, write_packed_entry_fn, out);
2339
2340 if (commit_lock_file(packed_ref_cache->lock)) {
2341 save_errno = errno;
2342 error = -1;
2343 }
2344 packed_ref_cache->lock = NULL;
2345 release_packed_ref_cache(packed_ref_cache);
2346 errno = save_errno;
2347 return error;
2348 }
2349
2350 void rollback_packed_refs(void)
2351 {
2352 struct packed_ref_cache *packed_ref_cache =
2353 get_packed_ref_cache(&ref_cache);
2354
2355 if (!packed_ref_cache->lock)
2356 die("internal error: packed-refs not locked");
2357 rollback_lock_file(packed_ref_cache->lock);
2358 packed_ref_cache->lock = NULL;
2359 release_packed_ref_cache(packed_ref_cache);
2360 clear_packed_ref_cache(&ref_cache);
2361 }
2362
2363 struct ref_to_prune {
2364 struct ref_to_prune *next;
2365 unsigned char sha1[20];
2366 char name[FLEX_ARRAY];
2367 };
2368
2369 struct pack_refs_cb_data {
2370 unsigned int flags;
2371 struct ref_dir *packed_refs;
2372 struct ref_to_prune *ref_to_prune;
2373 };
2374
2375 /*
2376 * An each_ref_entry_fn that is run over loose references only. If
2377 * the loose reference can be packed, add an entry in the packed ref
2378 * cache. If the reference should be pruned, also add it to
2379 * ref_to_prune in the pack_refs_cb_data.
2380 */
2381 static int pack_if_possible_fn(struct ref_entry *entry, void *cb_data)
2382 {
2383 struct pack_refs_cb_data *cb = cb_data;
2384 enum peel_status peel_status;
2385 struct ref_entry *packed_entry;
2386 int is_tag_ref = starts_with(entry->name, "refs/tags/");
2387
2388 /* ALWAYS pack tags */
2389 if (!(cb->flags & PACK_REFS_ALL) && !is_tag_ref)
2390 return 0;
2391
2392 /* Do not pack symbolic or broken refs: */
2393 if ((entry->flag & REF_ISSYMREF) || !ref_resolves_to_object(entry))
2394 return 0;
2395
2396 /* Add a packed ref cache entry equivalent to the loose entry. */
2397 peel_status = peel_entry(entry, 1);
2398 if (peel_status != PEEL_PEELED && peel_status != PEEL_NON_TAG)
2399 die("internal error peeling reference %s (%s)",
2400 entry->name, sha1_to_hex(entry->u.value.sha1));
2401 packed_entry = find_ref(cb->packed_refs, entry->name);
2402 if (packed_entry) {
2403 /* Overwrite existing packed entry with info from loose entry */
2404 packed_entry->flag = REF_ISPACKED | REF_KNOWS_PEELED;
2405 hashcpy(packed_entry->u.value.sha1, entry->u.value.sha1);
2406 } else {
2407 packed_entry = create_ref_entry(entry->name, entry->u.value.sha1,
2408 REF_ISPACKED | REF_KNOWS_PEELED, 0);
2409 add_ref(cb->packed_refs, packed_entry);
2410 }
2411 hashcpy(packed_entry->u.value.peeled, entry->u.value.peeled);
2412
2413 /* Schedule the loose reference for pruning if requested. */
2414 if ((cb->flags & PACK_REFS_PRUNE)) {
2415 int namelen = strlen(entry->name) + 1;
2416 struct ref_to_prune *n = xcalloc(1, sizeof(*n) + namelen);
2417 hashcpy(n->sha1, entry->u.value.sha1);
2418 strcpy(n->name, entry->name);
2419 n->next = cb->ref_to_prune;
2420 cb->ref_to_prune = n;
2421 }
2422 return 0;
2423 }
2424
2425 /*
2426 * Remove empty parents, but spare refs/ and immediate subdirs.
2427 * Note: munges *name.
2428 */
2429 static void try_remove_empty_parents(char *name)
2430 {
2431 char *p, *q;
2432 int i;
2433 p = name;
2434 for (i = 0; i < 2; i++) { /* refs/{heads,tags,...}/ */
2435 while (*p && *p != '/')
2436 p++;
2437 /* tolerate duplicate slashes; see check_refname_format() */
2438 while (*p == '/')
2439 p++;
2440 }
2441 for (q = p; *q; q++)
2442 ;
2443 while (1) {
2444 while (q > p && *q != '/')
2445 q--;
2446 while (q > p && *(q-1) == '/')
2447 q--;
2448 if (q == p)
2449 break;
2450 *q = '\0';
2451 if (rmdir(git_path("%s", name)))
2452 break;
2453 }
2454 }
2455
2456 /* make sure nobody touched the ref, and unlink */
2457 static void prune_ref(struct ref_to_prune *r)
2458 {
2459 struct ref_transaction *transaction;
2460 struct strbuf err = STRBUF_INIT;
2461
2462 if (check_refname_format(r->name, 0))
2463 return;
2464
2465 transaction = ref_transaction_begin(&err);
2466 if (!transaction ||
2467 ref_transaction_delete(transaction, r->name, r->sha1,
2468 REF_ISPRUNING, 1, NULL, &err) ||
2469 ref_transaction_commit(transaction, &err)) {
2470 ref_transaction_free(transaction);
2471 error("%s", err.buf);
2472 strbuf_release(&err);
2473 return;
2474 }
2475 ref_transaction_free(transaction);
2476 strbuf_release(&err);
2477 try_remove_empty_parents(r->name);
2478 }
2479
2480 static void prune_refs(struct ref_to_prune *r)
2481 {
2482 while (r) {
2483 prune_ref(r);
2484 r = r->next;
2485 }
2486 }
2487
2488 int pack_refs(unsigned int flags)
2489 {
2490 struct pack_refs_cb_data cbdata;
2491
2492 memset(&cbdata, 0, sizeof(cbdata));
2493 cbdata.flags = flags;
2494
2495 lock_packed_refs(LOCK_DIE_ON_ERROR);
2496 cbdata.packed_refs = get_packed_refs(&ref_cache);
2497
2498 do_for_each_entry_in_dir(get_loose_refs(&ref_cache), 0,
2499 pack_if_possible_fn, &cbdata);
2500
2501 if (commit_packed_refs())
2502 die_errno("unable to overwrite old ref-pack file");
2503
2504 prune_refs(cbdata.ref_to_prune);
2505 return 0;
2506 }
2507
2508 /*
2509 * If entry is no longer needed in packed-refs, add it to the string
2510 * list pointed to by cb_data. Reasons for deleting entries:
2511 *
2512 * - Entry is broken.
2513 * - Entry is overridden by a loose ref.
2514 * - Entry does not point at a valid object.
2515 *
2516 * In the first and third cases, also emit an error message because these
2517 * are indications of repository corruption.
2518 */
2519 static int curate_packed_ref_fn(struct ref_entry *entry, void *cb_data)
2520 {
2521 struct string_list *refs_to_delete = cb_data;
2522
2523 if (entry->flag & REF_ISBROKEN) {
2524 /* This shouldn't happen to packed refs. */
2525 error("%s is broken!", entry->name);
2526 string_list_append(refs_to_delete, entry->name);
2527 return 0;
2528 }
2529 if (!has_sha1_file(entry->u.value.sha1)) {
2530 unsigned char sha1[20];
2531 int flags;
2532
2533 if (read_ref_full(entry->name, 0, sha1, &flags))
2534 /* We should at least have found the packed ref. */
2535 die("Internal error");
2536 if ((flags & REF_ISSYMREF) || !(flags & REF_ISPACKED)) {
2537 /*
2538 * This packed reference is overridden by a
2539 * loose reference, so it is OK that its value
2540 * is no longer valid; for example, it might
2541 * refer to an object that has been garbage
2542 * collected. For this purpose we don't even
2543 * care whether the loose reference itself is
2544 * invalid, broken, symbolic, etc. Silently
2545 * remove the packed reference.
2546 */
2547 string_list_append(refs_to_delete, entry->name);
2548 return 0;
2549 }
2550 /*
2551 * There is no overriding loose reference, so the fact
2552 * that this reference doesn't refer to a valid object
2553 * indicates some kind of repository corruption.
2554 * Report the problem, then omit the reference from
2555 * the output.
2556 */
2557 error("%s does not point to a valid object!", entry->name);
2558 string_list_append(refs_to_delete, entry->name);
2559 return 0;
2560 }
2561
2562 return 0;
2563 }
2564
2565 int repack_without_refs(const char **refnames, int n, struct strbuf *err)
2566 {
2567 struct ref_dir *packed;
2568 struct string_list refs_to_delete = STRING_LIST_INIT_DUP;
2569 struct string_list_item *ref_to_delete;
2570 int i, ret, removed = 0;
2571
2572 /* Look for a packed ref */
2573 for (i = 0; i < n; i++)
2574 if (get_packed_ref(refnames[i]))
2575 break;
2576
2577 /* Avoid locking if we have nothing to do */
2578 if (i == n)
2579 return 0; /* no refname exists in packed refs */
2580
2581 if (lock_packed_refs(0)) {
2582 if (err) {
2583 unable_to_lock_message(git_path("packed-refs"), errno,
2584 err);
2585 return -1;
2586 }
2587 unable_to_lock_error(git_path("packed-refs"), errno);
2588 return error("cannot delete '%s' from packed refs", refnames[i]);
2589 }
2590 packed = get_packed_refs(&ref_cache);
2591
2592 /* Remove refnames from the cache */
2593 for (i = 0; i < n; i++)
2594 if (remove_entry(packed, refnames[i]) != -1)
2595 removed = 1;
2596 if (!removed) {
2597 /*
2598 * All packed entries disappeared while we were
2599 * acquiring the lock.
2600 */
2601 rollback_packed_refs();
2602 return 0;
2603 }
2604
2605 /* Remove any other accumulated cruft */
2606 do_for_each_entry_in_dir(packed, 0, curate_packed_ref_fn, &refs_to_delete);
2607 for_each_string_list_item(ref_to_delete, &refs_to_delete) {
2608 if (remove_entry(packed, ref_to_delete->string) == -1)
2609 die("internal error");
2610 }
2611
2612 /* Write what remains */
2613 ret = commit_packed_refs();
2614 if (ret && err)
2615 strbuf_addf(err, "unable to overwrite old ref-pack file: %s",
2616 strerror(errno));
2617 return ret;
2618 }
2619
2620 static int delete_ref_loose(struct ref_lock *lock, int flag, struct strbuf *err)
2621 {
2622 if (!(flag & REF_ISPACKED) || flag & REF_ISSYMREF) {
2623 /*
2624 * loose. The loose file name is the same as the
2625 * lockfile name, minus ".lock":
2626 */
2627 char *loose_filename = get_locked_file_path(lock->lk);
2628 int res = unlink_or_msg(loose_filename, err);
2629 free(loose_filename);
2630 if (res)
2631 return 1;
2632 }
2633 return 0;
2634 }
2635
2636 int delete_ref(const char *refname, const unsigned char *sha1, int delopt)
2637 {
2638 struct ref_transaction *transaction;
2639 struct strbuf err = STRBUF_INIT;
2640
2641 transaction = ref_transaction_begin(&err);
2642 if (!transaction ||
2643 ref_transaction_delete(transaction, refname, sha1, delopt,
2644 sha1 && !is_null_sha1(sha1), NULL, &err) ||
2645 ref_transaction_commit(transaction, &err)) {
2646 error("%s", err.buf);
2647 ref_transaction_free(transaction);
2648 strbuf_release(&err);
2649 return 1;
2650 }
2651 ref_transaction_free(transaction);
2652 strbuf_release(&err);
2653 return 0;
2654 }
2655
2656 /*
2657 * People using contrib's git-new-workdir have .git/logs/refs ->
2658 * /some/other/path/.git/logs/refs, and that may live on another device.
2659 *
2660 * IOW, to avoid cross device rename errors, the temporary renamed log must
2661 * live into logs/refs.
2662 */
2663 #define TMP_RENAMED_LOG "logs/refs/.tmp-renamed-log"
2664
2665 static int rename_tmp_log(const char *newrefname)
2666 {
2667 int attempts_remaining = 4;
2668
2669 retry:
2670 switch (safe_create_leading_directories(git_path("logs/%s", newrefname))) {
2671 case SCLD_OK:
2672 break; /* success */
2673 case SCLD_VANISHED:
2674 if (--attempts_remaining > 0)
2675 goto retry;
2676 /* fall through */
2677 default:
2678 error("unable to create directory for %s", newrefname);
2679 return -1;
2680 }
2681
2682 if (rename(git_path(TMP_RENAMED_LOG), git_path("logs/%s", newrefname))) {
2683 if ((errno==EISDIR || errno==ENOTDIR) && --attempts_remaining > 0) {
2684 /*
2685 * rename(a, b) when b is an existing
2686 * directory ought to result in ISDIR, but
2687 * Solaris 5.8 gives ENOTDIR. Sheesh.
2688 */
2689 if (remove_empty_directories(git_path("logs/%s", newrefname))) {
2690 error("Directory not empty: logs/%s", newrefname);
2691 return -1;
2692 }
2693 goto retry;
2694 } else if (errno == ENOENT && --attempts_remaining > 0) {
2695 /*
2696 * Maybe another process just deleted one of
2697 * the directories in the path to newrefname.
2698 * Try again from the beginning.
2699 */
2700 goto retry;
2701 } else {
2702 error("unable to move logfile "TMP_RENAMED_LOG" to logs/%s: %s",
2703 newrefname, strerror(errno));
2704 return -1;
2705 }
2706 }
2707 return 0;
2708 }
2709
2710 static int rename_ref_available(const char *oldname, const char *newname)
2711 {
2712 struct string_list skip = STRING_LIST_INIT_NODUP;
2713 int ret;
2714
2715 string_list_insert(&skip, oldname);
2716 ret = is_refname_available(newname, &skip, get_packed_refs(&ref_cache))
2717 && is_refname_available(newname, &skip, get_loose_refs(&ref_cache));
2718 string_list_clear(&skip, 0);
2719 return ret;
2720 }
2721
2722 static int write_ref_sha1(struct ref_lock *lock, const unsigned char *sha1,
2723 const char *logmsg);
2724
2725 int rename_ref(const char *oldrefname, const char *newrefname, const char *logmsg)
2726 {
2727 unsigned char sha1[20], orig_sha1[20];
2728 int flag = 0, logmoved = 0;
2729 struct ref_lock *lock;
2730 struct stat loginfo;
2731 int log = !lstat(git_path("logs/%s", oldrefname), &loginfo);
2732 const char *symref = NULL;
2733
2734 if (log && S_ISLNK(loginfo.st_mode))
2735 return error("reflog for %s is a symlink", oldrefname);
2736
2737 symref = resolve_ref_unsafe(oldrefname, RESOLVE_REF_READING,
2738 orig_sha1, &flag);
2739 if (flag & REF_ISSYMREF)
2740 return error("refname %s is a symbolic ref, renaming it is not supported",
2741 oldrefname);
2742 if (!symref)
2743 return error("refname %s not found", oldrefname);
2744
2745 if (!rename_ref_available(oldrefname, newrefname))
2746 return 1;
2747
2748 if (log && rename(git_path("logs/%s", oldrefname), git_path(TMP_RENAMED_LOG)))
2749 return error("unable to move logfile logs/%s to "TMP_RENAMED_LOG": %s",
2750 oldrefname, strerror(errno));
2751
2752 if (delete_ref(oldrefname, orig_sha1, REF_NODEREF)) {
2753 error("unable to delete old %s", oldrefname);
2754 goto rollback;
2755 }
2756
2757 if (!read_ref_full(newrefname, RESOLVE_REF_READING, sha1, NULL) &&
2758 delete_ref(newrefname, sha1, REF_NODEREF)) {
2759 if (errno==EISDIR) {
2760 if (remove_empty_directories(git_path("%s", newrefname))) {
2761 error("Directory not empty: %s", newrefname);
2762 goto rollback;
2763 }
2764 } else {
2765 error("unable to delete existing %s", newrefname);
2766 goto rollback;
2767 }
2768 }
2769
2770 if (log && rename_tmp_log(newrefname))
2771 goto rollback;
2772
2773 logmoved = log;
2774
2775 lock = lock_ref_sha1_basic(newrefname, NULL, NULL, 0, NULL);
2776 if (!lock) {
2777 error("unable to lock %s for update", newrefname);
2778 goto rollback;
2779 }
2780 lock->force_write = 1;
2781 hashcpy(lock->old_sha1, orig_sha1);
2782 if (write_ref_sha1(lock, orig_sha1, logmsg)) {
2783 error("unable to write current sha1 into %s", newrefname);
2784 goto rollback;
2785 }
2786
2787 return 0;
2788
2789 rollback:
2790 lock = lock_ref_sha1_basic(oldrefname, NULL, NULL, 0, NULL);
2791 if (!lock) {
2792 error("unable to lock %s for rollback", oldrefname);
2793 goto rollbacklog;
2794 }
2795
2796 lock->force_write = 1;
2797 flag = log_all_ref_updates;
2798 log_all_ref_updates = 0;
2799 if (write_ref_sha1(lock, orig_sha1, NULL))
2800 error("unable to write current sha1 into %s", oldrefname);
2801 log_all_ref_updates = flag;
2802
2803 rollbacklog:
2804 if (logmoved && rename(git_path("logs/%s", newrefname), git_path("logs/%s", oldrefname)))
2805 error("unable to restore logfile %s from %s: %s",
2806 oldrefname, newrefname, strerror(errno));
2807 if (!logmoved && log &&
2808 rename(git_path(TMP_RENAMED_LOG), git_path("logs/%s", oldrefname)))
2809 error("unable to restore logfile %s from "TMP_RENAMED_LOG": %s",
2810 oldrefname, strerror(errno));
2811
2812 return 1;
2813 }
2814
2815 int close_ref(struct ref_lock *lock)
2816 {
2817 if (close_lock_file(lock->lk))
2818 return -1;
2819 lock->lock_fd = -1;
2820 return 0;
2821 }
2822
2823 int commit_ref(struct ref_lock *lock)
2824 {
2825 if (commit_lock_file(lock->lk))
2826 return -1;
2827 lock->lock_fd = -1;
2828 return 0;
2829 }
2830
2831 void unlock_ref(struct ref_lock *lock)
2832 {
2833 /* Do not free lock->lk -- atexit() still looks at them */
2834 if (lock->lk)
2835 rollback_lock_file(lock->lk);
2836 free(lock->ref_name);
2837 free(lock->orig_ref_name);
2838 free(lock);
2839 }
2840
2841 /*
2842 * copy the reflog message msg to buf, which has been allocated sufficiently
2843 * large, while cleaning up the whitespaces. Especially, convert LF to space,
2844 * because reflog file is one line per entry.
2845 */
2846 static int copy_msg(char *buf, const char *msg)
2847 {
2848 char *cp = buf;
2849 char c;
2850 int wasspace = 1;
2851
2852 *cp++ = '\t';
2853 while ((c = *msg++)) {
2854 if (wasspace && isspace(c))
2855 continue;
2856 wasspace = isspace(c);
2857 if (wasspace)
2858 c = ' ';
2859 *cp++ = c;
2860 }
2861 while (buf < cp && isspace(cp[-1]))
2862 cp--;
2863 *cp++ = '\n';
2864 return cp - buf;
2865 }
2866
2867 /* This function must set a meaningful errno on failure */
2868 int log_ref_setup(const char *refname, char *logfile, int bufsize)
2869 {
2870 int logfd, oflags = O_APPEND | O_WRONLY;
2871
2872 git_snpath(logfile, bufsize, "logs/%s", refname);
2873 if (log_all_ref_updates &&
2874 (starts_with(refname, "refs/heads/") ||
2875 starts_with(refname, "refs/remotes/") ||
2876 starts_with(refname, "refs/notes/") ||
2877 !strcmp(refname, "HEAD"))) {
2878 if (safe_create_leading_directories(logfile) < 0) {
2879 int save_errno = errno;
2880 error("unable to create directory for %s", logfile);
2881 errno = save_errno;
2882 return -1;
2883 }
2884 oflags |= O_CREAT;
2885 }
2886
2887 logfd = open(logfile, oflags, 0666);
2888 if (logfd < 0) {
2889 if (!(oflags & O_CREAT) && errno == ENOENT)
2890 return 0;
2891
2892 if ((oflags & O_CREAT) && errno == EISDIR) {
2893 if (remove_empty_directories(logfile)) {
2894 int save_errno = errno;
2895 error("There are still logs under '%s'",
2896 logfile);
2897 errno = save_errno;
2898 return -1;
2899 }
2900 logfd = open(logfile, oflags, 0666);
2901 }
2902
2903 if (logfd < 0) {
2904 int save_errno = errno;
2905 error("Unable to append to %s: %s", logfile,
2906 strerror(errno));
2907 errno = save_errno;
2908 return -1;
2909 }
2910 }
2911
2912 adjust_shared_perm(logfile);
2913 close(logfd);
2914 return 0;
2915 }
2916
2917 static int log_ref_write(const char *refname, const unsigned char *old_sha1,
2918 const unsigned char *new_sha1, const char *msg)
2919 {
2920 int logfd, result, written, oflags = O_APPEND | O_WRONLY;
2921 unsigned maxlen, len;
2922 int msglen;
2923 char log_file[PATH_MAX];
2924 char *logrec;
2925 const char *committer;
2926
2927 if (log_all_ref_updates < 0)
2928 log_all_ref_updates = !is_bare_repository();
2929
2930 result = log_ref_setup(refname, log_file, sizeof(log_file));
2931 if (result)
2932 return result;
2933
2934 logfd = open(log_file, oflags);
2935 if (logfd < 0)
2936 return 0;
2937 msglen = msg ? strlen(msg) : 0;
2938 committer = git_committer_info(0);
2939 maxlen = strlen(committer) + msglen + 100;
2940 logrec = xmalloc(maxlen);
2941 len = sprintf(logrec, "%s %s %s\n",
2942 sha1_to_hex(old_sha1),
2943 sha1_to_hex(new_sha1),
2944 committer);
2945 if (msglen)
2946 len += copy_msg(logrec + len - 1, msg) - 1;
2947 written = len <= maxlen ? write_in_full(logfd, logrec, len) : -1;
2948 free(logrec);
2949 if (written != len) {
2950 int save_errno = errno;
2951 close(logfd);
2952 error("Unable to append to %s", log_file);
2953 errno = save_errno;
2954 return -1;
2955 }
2956 if (close(logfd)) {
2957 int save_errno = errno;
2958 error("Unable to append to %s", log_file);
2959 errno = save_errno;
2960 return -1;
2961 }
2962 return 0;
2963 }
2964
2965 int is_branch(const char *refname)
2966 {
2967 return !strcmp(refname, "HEAD") || starts_with(refname, "refs/heads/");
2968 }
2969
2970 /*
2971 * Write sha1 into the ref specified by the lock. Make sure that errno
2972 * is sane on error.
2973 */
2974 static int write_ref_sha1(struct ref_lock *lock,
2975 const unsigned char *sha1, const char *logmsg)
2976 {
2977 static char term = '\n';
2978 struct object *o;
2979
2980 if (!lock) {
2981 errno = EINVAL;
2982 return -1;
2983 }
2984 if (!lock->force_write && !hashcmp(lock->old_sha1, sha1)) {
2985 unlock_ref(lock);
2986 return 0;
2987 }
2988 o = parse_object(sha1);
2989 if (!o) {
2990 error("Trying to write ref %s with nonexistent object %s",
2991 lock->ref_name, sha1_to_hex(sha1));
2992 unlock_ref(lock);
2993 errno = EINVAL;
2994 return -1;
2995 }
2996 if (o->type != OBJ_COMMIT && is_branch(lock->ref_name)) {
2997 error("Trying to write non-commit object %s to branch %s",
2998 sha1_to_hex(sha1), lock->ref_name);
2999 unlock_ref(lock);
3000 errno = EINVAL;
3001 return -1;
3002 }
3003 if (write_in_full(lock->lock_fd, sha1_to_hex(sha1), 40) != 40 ||
3004 write_in_full(lock->lock_fd, &term, 1) != 1 ||
3005 close_ref(lock) < 0) {
3006 int save_errno = errno;
3007 error("Couldn't write %s", lock->lk->filename.buf);
3008 unlock_ref(lock);
3009 errno = save_errno;
3010 return -1;
3011 }
3012 clear_loose_ref_cache(&ref_cache);
3013 if (log_ref_write(lock->ref_name, lock->old_sha1, sha1, logmsg) < 0 ||
3014 (strcmp(lock->ref_name, lock->orig_ref_name) &&
3015 log_ref_write(lock->orig_ref_name, lock->old_sha1, sha1, logmsg) < 0)) {
3016 unlock_ref(lock);
3017 return -1;
3018 }
3019 if (strcmp(lock->orig_ref_name, "HEAD") != 0) {
3020 /*
3021 * Special hack: If a branch is updated directly and HEAD
3022 * points to it (may happen on the remote side of a push
3023 * for example) then logically the HEAD reflog should be
3024 * updated too.
3025 * A generic solution implies reverse symref information,
3026 * but finding all symrefs pointing to the given branch
3027 * would be rather costly for this rare event (the direct
3028 * update of a branch) to be worth it. So let's cheat and
3029 * check with HEAD only which should cover 99% of all usage
3030 * scenarios (even 100% of the default ones).
3031 */
3032 unsigned char head_sha1[20];
3033 int head_flag;
3034 const char *head_ref;
3035 head_ref = resolve_ref_unsafe("HEAD", RESOLVE_REF_READING,
3036 head_sha1, &head_flag);
3037 if (head_ref && (head_flag & REF_ISSYMREF) &&
3038 !strcmp(head_ref, lock->ref_name))
3039 log_ref_write("HEAD", lock->old_sha1, sha1, logmsg);
3040 }
3041 if (commit_ref(lock)) {
3042 error("Couldn't set %s", lock->ref_name);
3043 unlock_ref(lock);
3044 return -1;
3045 }
3046 unlock_ref(lock);
3047 return 0;
3048 }
3049
3050 int create_symref(const char *ref_target, const char *refs_heads_master,
3051 const char *logmsg)
3052 {
3053 const char *lockpath;
3054 char ref[1000];
3055 int fd, len, written;
3056 char *git_HEAD = git_pathdup("%s", ref_target);
3057 unsigned char old_sha1[20], new_sha1[20];
3058
3059 if (logmsg && read_ref(ref_target, old_sha1))
3060 hashclr(old_sha1);
3061
3062 if (safe_create_leading_directories(git_HEAD) < 0)
3063 return error("unable to create directory for %s", git_HEAD);
3064
3065 #ifndef NO_SYMLINK_HEAD
3066 if (prefer_symlink_refs) {
3067 unlink(git_HEAD);
3068 if (!symlink(refs_heads_master, git_HEAD))
3069 goto done;
3070 fprintf(stderr, "no symlink - falling back to symbolic ref\n");
3071 }
3072 #endif
3073
3074 len = snprintf(ref, sizeof(ref), "ref: %s\n", refs_heads_master);
3075 if (sizeof(ref) <= len) {
3076 error("refname too long: %s", refs_heads_master);
3077 goto error_free_return;
3078 }
3079 lockpath = mkpath("%s.lock", git_HEAD);
3080 fd = open(lockpath, O_CREAT | O_EXCL | O_WRONLY, 0666);
3081 if (fd < 0) {
3082 error("Unable to open %s for writing", lockpath);
3083 goto error_free_return;
3084 }
3085 written = write_in_full(fd, ref, len);
3086 if (close(fd) != 0 || written != len) {
3087 error("Unable to write to %s", lockpath);
3088 goto error_unlink_return;
3089 }
3090 if (rename(lockpath, git_HEAD) < 0) {
3091 error("Unable to create %s", git_HEAD);
3092 goto error_unlink_return;
3093 }
3094 if (adjust_shared_perm(git_HEAD)) {
3095 error("Unable to fix permissions on %s", lockpath);
3096 error_unlink_return:
3097 unlink_or_warn(lockpath);
3098 error_free_return:
3099 free(git_HEAD);
3100 return -1;
3101 }
3102
3103 #ifndef NO_SYMLINK_HEAD
3104 done:
3105 #endif
3106 if (logmsg && !read_ref(refs_heads_master, new_sha1))
3107 log_ref_write(ref_target, old_sha1, new_sha1, logmsg);
3108
3109 free(git_HEAD);
3110 return 0;
3111 }
3112
3113 struct read_ref_at_cb {
3114 const char *refname;
3115 unsigned long at_time;
3116 int cnt;
3117 int reccnt;
3118 unsigned char *sha1;
3119 int found_it;
3120
3121 unsigned char osha1[20];
3122 unsigned char nsha1[20];
3123 int tz;
3124 unsigned long date;
3125 char **msg;
3126 unsigned long *cutoff_time;
3127 int *cutoff_tz;
3128 int *cutoff_cnt;
3129 };
3130
3131 static int read_ref_at_ent(unsigned char *osha1, unsigned char *nsha1,
3132 const char *email, unsigned long timestamp, int tz,
3133 const char *message, void *cb_data)
3134 {
3135 struct read_ref_at_cb *cb = cb_data;
3136
3137 cb->reccnt++;
3138 cb->tz = tz;
3139 cb->date = timestamp;
3140
3141 if (timestamp <= cb->at_time || cb->cnt == 0) {
3142 if (cb->msg)
3143 *cb->msg = xstrdup(message);
3144 if (cb->cutoff_time)
3145 *cb->cutoff_time = timestamp;
3146 if (cb->cutoff_tz)
3147 *cb->cutoff_tz = tz;
3148 if (cb->cutoff_cnt)
3149 *cb->cutoff_cnt = cb->reccnt - 1;
3150 /*
3151 * we have not yet updated cb->[n|o]sha1 so they still
3152 * hold the values for the previous record.
3153 */
3154 if (!is_null_sha1(cb->osha1)) {
3155 hashcpy(cb->sha1, nsha1);
3156 if (hashcmp(cb->osha1, nsha1))
3157 warning("Log for ref %s has gap after %s.",
3158 cb->refname, show_date(cb->date, cb->tz, DATE_RFC2822));
3159 }
3160 else if (cb->date == cb->at_time)
3161 hashcpy(cb->sha1, nsha1);
3162 else if (hashcmp(nsha1, cb->sha1))
3163 warning("Log for ref %s unexpectedly ended on %s.",
3164 cb->refname, show_date(cb->date, cb->tz,
3165 DATE_RFC2822));
3166 hashcpy(cb->osha1, osha1);
3167 hashcpy(cb->nsha1, nsha1);
3168 cb->found_it = 1;
3169 return 1;
3170 }
3171 hashcpy(cb->osha1, osha1);
3172 hashcpy(cb->nsha1, nsha1);
3173 if (cb->cnt > 0)
3174 cb->cnt--;
3175 return 0;
3176 }
3177
3178 static int read_ref_at_ent_oldest(unsigned char *osha1, unsigned char *nsha1,
3179 const char *email, unsigned long timestamp,
3180 int tz, const char *message, void *cb_data)
3181 {
3182 struct read_ref_at_cb *cb = cb_data;
3183
3184 if (cb->msg)
3185 *cb->msg = xstrdup(message);
3186 if (cb->cutoff_time)
3187 *cb->cutoff_time = timestamp;
3188 if (cb->cutoff_tz)
3189 *cb->cutoff_tz = tz;
3190 if (cb->cutoff_cnt)
3191 *cb->cutoff_cnt = cb->reccnt;
3192 hashcpy(cb->sha1, osha1);
3193 if (is_null_sha1(cb->sha1))
3194 hashcpy(cb->sha1, nsha1);
3195 /* We just want the first entry */
3196 return 1;
3197 }
3198
3199 int read_ref_at(const char *refname, unsigned int flags, unsigned long at_time, int cnt,
3200 unsigned char *sha1, char **msg,
3201 unsigned long *cutoff_time, int *cutoff_tz, int *cutoff_cnt)
3202 {
3203 struct read_ref_at_cb cb;
3204
3205 memset(&cb, 0, sizeof(cb));
3206 cb.refname = refname;
3207 cb.at_time = at_time;
3208 cb.cnt = cnt;
3209 cb.msg = msg;
3210 cb.cutoff_time = cutoff_time;
3211 cb.cutoff_tz = cutoff_tz;
3212 cb.cutoff_cnt = cutoff_cnt;
3213 cb.sha1 = sha1;
3214
3215 for_each_reflog_ent_reverse(refname, read_ref_at_ent, &cb);
3216
3217 if (!cb.reccnt) {
3218 if (flags & GET_SHA1_QUIETLY)
3219 exit(128);
3220 else
3221 die("Log for %s is empty.", refname);
3222 }
3223 if (cb.found_it)
3224 return 0;
3225
3226 for_each_reflog_ent(refname, read_ref_at_ent_oldest, &cb);
3227
3228 return 1;
3229 }
3230
3231 int reflog_exists(const char *refname)
3232 {
3233 struct stat st;
3234
3235 return !lstat(git_path("logs/%s", refname), &st) &&
3236 S_ISREG(st.st_mode);
3237 }
3238
3239 int delete_reflog(const char *refname)
3240 {
3241 return remove_path(git_path("logs/%s", refname));
3242 }
3243
3244 static int show_one_reflog_ent(struct strbuf *sb, each_reflog_ent_fn fn, void *cb_data)
3245 {
3246 unsigned char osha1[20], nsha1[20];
3247 char *email_end, *message;
3248 unsigned long timestamp;
3249 int tz;
3250
3251 /* old SP new SP name <email> SP time TAB msg LF */
3252 if (sb->len < 83 || sb->buf[sb->len - 1] != '\n' ||
3253 get_sha1_hex(sb->buf, osha1) || sb->buf[40] != ' ' ||
3254 get_sha1_hex(sb->buf + 41, nsha1) || sb->buf[81] != ' ' ||
3255 !(email_end = strchr(sb->buf + 82, '>')) ||
3256 email_end[1] != ' ' ||
3257 !(timestamp = strtoul(email_end + 2, &message, 10)) ||
3258 !message || message[0] != ' ' ||
3259 (message[1] != '+' && message[1] != '-') ||
3260 !isdigit(message[2]) || !isdigit(message[3]) ||
3261 !isdigit(message[4]) || !isdigit(message[5]))
3262 return 0; /* corrupt? */
3263 email_end[1] = '\0';
3264 tz = strtol(message + 1, NULL, 10);
3265 if (message[6] != '\t')
3266 message += 6;
3267 else
3268 message += 7;
3269 return fn(osha1, nsha1, sb->buf + 82, timestamp, tz, message, cb_data);
3270 }
3271
3272 static char *find_beginning_of_line(char *bob, char *scan)
3273 {
3274 while (bob < scan && *(--scan) != '\n')
3275 ; /* keep scanning backwards */
3276 /*
3277 * Return either beginning of the buffer, or LF at the end of
3278 * the previous line.
3279 */
3280 return scan;
3281 }
3282
3283 int for_each_reflog_ent_reverse(const char *refname, each_reflog_ent_fn fn, void *cb_data)
3284 {
3285 struct strbuf sb = STRBUF_INIT;
3286 FILE *logfp;
3287 long pos;
3288 int ret = 0, at_tail = 1;
3289
3290 logfp = fopen(git_path("logs/%s", refname), "r");
3291 if (!logfp)
3292 return -1;
3293
3294 /* Jump to the end */
3295 if (fseek(logfp, 0, SEEK_END) < 0)
3296 return error("cannot seek back reflog for %s: %s",
3297 refname, strerror(errno));
3298 pos = ftell(logfp);
3299 while (!ret && 0 < pos) {
3300 int cnt;
3301 size_t nread;
3302 char buf[BUFSIZ];
3303 char *endp, *scanp;
3304
3305 /* Fill next block from the end */
3306 cnt = (sizeof(buf) < pos) ? sizeof(buf) : pos;
3307 if (fseek(logfp, pos - cnt, SEEK_SET))
3308 return error("cannot seek back reflog for %s: %s",
3309 refname, strerror(errno));
3310 nread = fread(buf, cnt, 1, logfp);
3311 if (nread != 1)
3312 return error("cannot read %d bytes from reflog for %s: %s",
3313 cnt, refname, strerror(errno));
3314 pos -= cnt;
3315
3316 scanp = endp = buf + cnt;
3317 if (at_tail && scanp[-1] == '\n')
3318 /* Looking at the final LF at the end of the file */
3319 scanp--;
3320 at_tail = 0;
3321
3322 while (buf < scanp) {
3323 /*
3324 * terminating LF of the previous line, or the beginning
3325 * of the buffer.
3326 */
3327 char *bp;
3328
3329 bp = find_beginning_of_line(buf, scanp);
3330
3331 if (*bp != '\n') {
3332 strbuf_splice(&sb, 0, 0, buf, endp - buf);
3333 if (pos)
3334 break; /* need to fill another block */
3335 scanp = buf - 1; /* leave loop */
3336 } else {
3337 /*
3338 * (bp + 1) thru endp is the beginning of the
3339 * current line we have in sb
3340 */
3341 strbuf_splice(&sb, 0, 0, bp + 1, endp - (bp + 1));
3342 scanp = bp;
3343 endp = bp + 1;
3344 }
3345 ret = show_one_reflog_ent(&sb, fn, cb_data);
3346 strbuf_reset(&sb);
3347 if (ret)
3348 break;
3349 }
3350
3351 }
3352 if (!ret && sb.len)
3353 ret = show_one_reflog_ent(&sb, fn, cb_data);
3354
3355 fclose(logfp);
3356 strbuf_release(&sb);
3357 return ret;
3358 }
3359
3360 int for_each_reflog_ent(const char *refname, each_reflog_ent_fn fn, void *cb_data)
3361 {
3362 FILE *logfp;
3363 struct strbuf sb = STRBUF_INIT;
3364 int ret = 0;
3365
3366 logfp = fopen(git_path("logs/%s", refname), "r");
3367 if (!logfp)
3368 return -1;
3369
3370 while (!ret && !strbuf_getwholeline(&sb, logfp, '\n'))
3371 ret = show_one_reflog_ent(&sb, fn, cb_data);
3372 fclose(logfp);
3373 strbuf_release(&sb);
3374 return ret;
3375 }
3376 /*
3377 * Call fn for each reflog in the namespace indicated by name. name
3378 * must be empty or end with '/'. Name will be used as a scratch
3379 * space, but its contents will be restored before return.
3380 */
3381 static int do_for_each_reflog(struct strbuf *name, each_ref_fn fn, void *cb_data)
3382 {
3383 DIR *d = opendir(git_path("logs/%s", name->buf));
3384 int retval = 0;
3385 struct dirent *de;
3386 int oldlen = name->len;
3387
3388 if (!d)
3389 return name->len ? errno : 0;
3390
3391 while ((de = readdir(d)) != NULL) {
3392 struct stat st;
3393
3394 if (de->d_name[0] == '.')
3395 continue;
3396 if (ends_with(de->d_name, ".lock"))
3397 continue;
3398 strbuf_addstr(name, de->d_name);
3399 if (stat(git_path("logs/%s", name->buf), &st) < 0) {
3400 ; /* silently ignore */
3401 } else {
3402 if (S_ISDIR(st.st_mode)) {
3403 strbuf_addch(name, '/');
3404 retval = do_for_each_reflog(name, fn, cb_data);
3405 } else {
3406 unsigned char sha1[20];
3407 if (read_ref_full(name->buf, 0, sha1, NULL))
3408 retval = error("bad ref for %s", name->buf);
3409 else
3410 retval = fn(name->buf, sha1, 0, cb_data);
3411 }
3412 if (retval)
3413 break;
3414 }
3415 strbuf_setlen(name, oldlen);
3416 }
3417 closedir(d);
3418 return retval;
3419 }
3420
3421 int for_each_reflog(each_ref_fn fn, void *cb_data)
3422 {
3423 int retval;
3424 struct strbuf name;
3425 strbuf_init(&name, PATH_MAX);
3426 retval = do_for_each_reflog(&name, fn, cb_data);
3427 strbuf_release(&name);
3428 return retval;
3429 }
3430
3431 /**
3432 * Information needed for a single ref update. Set new_sha1 to the
3433 * new value or to zero to delete the ref. To check the old value
3434 * while locking the ref, set have_old to 1 and set old_sha1 to the
3435 * value or to zero to ensure the ref does not exist before update.
3436 */
3437 struct ref_update {
3438 unsigned char new_sha1[20];
3439 unsigned char old_sha1[20];
3440 int flags; /* REF_NODEREF? */
3441 int have_old; /* 1 if old_sha1 is valid, 0 otherwise */
3442 struct ref_lock *lock;
3443 int type;
3444 char *msg;
3445 const char refname[FLEX_ARRAY];
3446 };
3447
3448 /*
3449 * Transaction states.
3450 * OPEN: The transaction is in a valid state and can accept new updates.
3451 * An OPEN transaction can be committed.
3452 * CLOSED: A closed transaction is no longer active and no other operations
3453 * than free can be used on it in this state.
3454 * A transaction can either become closed by successfully committing
3455 * an active transaction or if there is a failure while building
3456 * the transaction thus rendering it failed/inactive.
3457 */
3458 enum ref_transaction_state {
3459 REF_TRANSACTION_OPEN = 0,
3460 REF_TRANSACTION_CLOSED = 1
3461 };
3462
3463 /*
3464 * Data structure for holding a reference transaction, which can
3465 * consist of checks and updates to multiple references, carried out
3466 * as atomically as possible. This structure is opaque to callers.
3467 */
3468 struct ref_transaction {
3469 struct ref_update **updates;
3470 size_t alloc;
3471 size_t nr;
3472 enum ref_transaction_state state;
3473 };
3474
3475 struct ref_transaction *ref_transaction_begin(struct strbuf *err)
3476 {
3477 return xcalloc(1, sizeof(struct ref_transaction));
3478 }
3479
3480 void ref_transaction_free(struct ref_transaction *transaction)
3481 {
3482 int i;
3483
3484 if (!transaction)
3485 return;
3486
3487 for (i = 0; i < transaction->nr; i++) {
3488 free(transaction->updates[i]->msg);
3489 free(transaction->updates[i]);
3490 }
3491 free(transaction->updates);
3492 free(transaction);
3493 }
3494
3495 static struct ref_update *add_update(struct ref_transaction *transaction,
3496 const char *refname)
3497 {
3498 size_t len = strlen(refname);
3499 struct ref_update *update = xcalloc(1, sizeof(*update) + len + 1);
3500
3501 strcpy((char *)update->refname, refname);
3502 ALLOC_GROW(transaction->updates, transaction->nr + 1, transaction->alloc);
3503 transaction->updates[transaction->nr++] = update;
3504 return update;
3505 }
3506
3507 int ref_transaction_update(struct ref_transaction *transaction,
3508 const char *refname,
3509 const unsigned char *new_sha1,
3510 const unsigned char *old_sha1,
3511 int flags, int have_old, const char *msg,
3512 struct strbuf *err)
3513 {
3514 struct ref_update *update;
3515
3516 if (transaction->state != REF_TRANSACTION_OPEN)
3517 die("BUG: update called for transaction that is not open");
3518
3519 if (have_old && !old_sha1)
3520 die("BUG: have_old is true but old_sha1 is NULL");
3521
3522 update = add_update(transaction, refname);
3523 hashcpy(update->new_sha1, new_sha1);
3524 update->flags = flags;
3525 update->have_old = have_old;
3526 if (have_old)
3527 hashcpy(update->old_sha1, old_sha1);
3528 if (msg)
3529 update->msg = xstrdup(msg);
3530 return 0;
3531 }
3532
3533 int ref_transaction_create(struct ref_transaction *transaction,
3534 const char *refname,
3535 const unsigned char *new_sha1,
3536 int flags, const char *msg,
3537 struct strbuf *err)
3538 {
3539 struct ref_update *update;
3540
3541 if (transaction->state != REF_TRANSACTION_OPEN)
3542 die("BUG: create called for transaction that is not open");
3543
3544 if (!new_sha1 || is_null_sha1(new_sha1))
3545 die("BUG: create ref with null new_sha1");
3546
3547 update = add_update(transaction, refname);
3548
3549 hashcpy(update->new_sha1, new_sha1);
3550 hashclr(update->old_sha1);
3551 update->flags = flags;
3552 update->have_old = 1;
3553 if (msg)
3554 update->msg = xstrdup(msg);
3555 return 0;
3556 }
3557
3558 int ref_transaction_delete(struct ref_transaction *transaction,
3559 const char *refname,
3560 const unsigned char *old_sha1,
3561 int flags, int have_old, const char *msg,
3562 struct strbuf *err)
3563 {
3564 struct ref_update *update;
3565
3566 if (transaction->state != REF_TRANSACTION_OPEN)
3567 die("BUG: delete called for transaction that is not open");
3568
3569 if (have_old && !old_sha1)
3570 die("BUG: have_old is true but old_sha1 is NULL");
3571
3572 update = add_update(transaction, refname);
3573 update->flags = flags;
3574 update->have_old = have_old;
3575 if (have_old) {
3576 assert(!is_null_sha1(old_sha1));
3577 hashcpy(update->old_sha1, old_sha1);
3578 }
3579 if (msg)
3580 update->msg = xstrdup(msg);
3581 return 0;
3582 }
3583
3584 int update_ref(const char *action, const char *refname,
3585 const unsigned char *sha1, const unsigned char *oldval,
3586 int flags, enum action_on_err onerr)
3587 {
3588 struct ref_transaction *t;
3589 struct strbuf err = STRBUF_INIT;
3590
3591 t = ref_transaction_begin(&err);
3592 if (!t ||
3593 ref_transaction_update(t, refname, sha1, oldval, flags,
3594 !!oldval, action, &err) ||
3595 ref_transaction_commit(t, &err)) {
3596 const char *str = "update_ref failed for ref '%s': %s";
3597
3598 ref_transaction_free(t);
3599 switch (onerr) {
3600 case UPDATE_REFS_MSG_ON_ERR:
3601 error(str, refname, err.buf);
3602 break;
3603 case UPDATE_REFS_DIE_ON_ERR:
3604 die(str, refname, err.buf);
3605 break;
3606 case UPDATE_REFS_QUIET_ON_ERR:
3607 break;
3608 }
3609 strbuf_release(&err);
3610 return 1;
3611 }
3612 strbuf_release(&err);
3613 ref_transaction_free(t);
3614 return 0;
3615 }
3616
3617 static int ref_update_compare(const void *r1, const void *r2)
3618 {
3619 const struct ref_update * const *u1 = r1;
3620 const struct ref_update * const *u2 = r2;
3621 return strcmp((*u1)->refname, (*u2)->refname);
3622 }
3623
3624 static int ref_update_reject_duplicates(struct ref_update **updates, int n,
3625 struct strbuf *err)
3626 {
3627 int i;
3628 for (i = 1; i < n; i++)
3629 if (!strcmp(updates[i - 1]->refname, updates[i]->refname)) {
3630 const char *str =
3631 "Multiple updates for ref '%s' not allowed.";
3632 if (err)
3633 strbuf_addf(err, str, updates[i]->refname);
3634
3635 return 1;
3636 }
3637 return 0;
3638 }
3639
3640 int ref_transaction_commit(struct ref_transaction *transaction,
3641 struct strbuf *err)
3642 {
3643 int ret = 0, delnum = 0, i;
3644 const char **delnames;
3645 int n = transaction->nr;
3646 struct ref_update **updates = transaction->updates;
3647
3648 if (transaction->state != REF_TRANSACTION_OPEN)
3649 die("BUG: commit called for transaction that is not open");
3650
3651 if (!n) {
3652 transaction->state = REF_TRANSACTION_CLOSED;
3653 return 0;
3654 }
3655
3656 /* Allocate work space */
3657 delnames = xmalloc(sizeof(*delnames) * n);
3658
3659 /* Copy, sort, and reject duplicate refs */
3660 qsort(updates, n, sizeof(*updates), ref_update_compare);
3661 if (ref_update_reject_duplicates(updates, n, err)) {
3662 ret = TRANSACTION_GENERIC_ERROR;
3663 goto cleanup;
3664 }
3665
3666 /* Acquire all locks while verifying old values */
3667 for (i = 0; i < n; i++) {
3668 struct ref_update *update = updates[i];
3669 int flags = update->flags;
3670
3671 if (is_null_sha1(update->new_sha1))
3672 flags |= REF_DELETING;
3673 update->lock = lock_ref_sha1_basic(update->refname,
3674 (update->have_old ?
3675 update->old_sha1 :
3676 NULL),
3677 NULL,
3678 flags,
3679 &update->type);
3680 if (!update->lock) {
3681 ret = (errno == ENOTDIR)
3682 ? TRANSACTION_NAME_CONFLICT
3683 : TRANSACTION_GENERIC_ERROR;
3684 if (err)
3685 strbuf_addf(err, "Cannot lock the ref '%s'.",
3686 update->refname);
3687 goto cleanup;
3688 }
3689 }
3690
3691 /* Perform updates first so live commits remain referenced */
3692 for (i = 0; i < n; i++) {
3693 struct ref_update *update = updates[i];
3694
3695 if (!is_null_sha1(update->new_sha1)) {
3696 if (write_ref_sha1(update->lock, update->new_sha1,
3697 update->msg)) {
3698 update->lock = NULL; /* freed by write_ref_sha1 */
3699 if (err)
3700 strbuf_addf(err, "Cannot update the ref '%s'.",
3701 update->refname);
3702 ret = TRANSACTION_GENERIC_ERROR;
3703 goto cleanup;
3704 }
3705 update->lock = NULL; /* freed by write_ref_sha1 */
3706 }
3707 }
3708
3709 /* Perform deletes now that updates are safely completed */
3710 for (i = 0; i < n; i++) {
3711 struct ref_update *update = updates[i];
3712
3713 if (update->lock) {
3714 if (delete_ref_loose(update->lock, update->type, err))
3715 ret = TRANSACTION_GENERIC_ERROR;
3716
3717 if (!(update->flags & REF_ISPRUNING))
3718 delnames[delnum++] = update->lock->ref_name;
3719 }
3720 }
3721
3722 if (repack_without_refs(delnames, delnum, err))
3723 ret = TRANSACTION_GENERIC_ERROR;
3724 for (i = 0; i < delnum; i++)
3725 unlink_or_warn(git_path("logs/%s", delnames[i]));
3726 clear_loose_ref_cache(&ref_cache);
3727
3728 cleanup:
3729 transaction->state = REF_TRANSACTION_CLOSED;
3730
3731 for (i = 0; i < n; i++)
3732 if (updates[i]->lock)
3733 unlock_ref(updates[i]->lock);
3734 free(delnames);
3735 return ret;
3736 }
3737
3738 char *shorten_unambiguous_ref(const char *refname, int strict)
3739 {
3740 int i;
3741 static char **scanf_fmts;
3742 static int nr_rules;
3743 char *short_name;
3744
3745 if (!nr_rules) {
3746 /*
3747 * Pre-generate scanf formats from ref_rev_parse_rules[].
3748 * Generate a format suitable for scanf from a
3749 * ref_rev_parse_rules rule by interpolating "%s" at the
3750 * location of the "%.*s".
3751 */
3752 size_t total_len = 0;
3753 size_t offset = 0;
3754
3755 /* the rule list is NULL terminated, count them first */
3756 for (nr_rules = 0; ref_rev_parse_rules[nr_rules]; nr_rules++)
3757 /* -2 for strlen("%.*s") - strlen("%s"); +1 for NUL */
3758 total_len += strlen(ref_rev_parse_rules[nr_rules]) - 2 + 1;
3759
3760 scanf_fmts = xmalloc(nr_rules * sizeof(char *) + total_len);
3761
3762 offset = 0;
3763 for (i = 0; i < nr_rules; i++) {
3764 assert(offset < total_len);
3765 scanf_fmts[i] = (char *)&scanf_fmts[nr_rules] + offset;
3766 offset += snprintf(scanf_fmts[i], total_len - offset,
3767 ref_rev_parse_rules[i], 2, "%s") + 1;
3768 }
3769 }
3770
3771 /* bail out if there are no rules */
3772 if (!nr_rules)
3773 return xstrdup(refname);
3774
3775 /* buffer for scanf result, at most refname must fit */
3776 short_name = xstrdup(refname);
3777
3778 /* skip first rule, it will always match */
3779 for (i = nr_rules - 1; i > 0 ; --i) {
3780 int j;
3781 int rules_to_fail = i;
3782 int short_name_len;
3783
3784 if (1 != sscanf(refname, scanf_fmts[i], short_name))
3785 continue;
3786
3787 short_name_len = strlen(short_name);
3788
3789 /*
3790 * in strict mode, all (except the matched one) rules
3791 * must fail to resolve to a valid non-ambiguous ref
3792 */
3793 if (strict)
3794 rules_to_fail = nr_rules;
3795
3796 /*
3797 * check if the short name resolves to a valid ref,
3798 * but use only rules prior to the matched one
3799 */
3800 for (j = 0; j < rules_to_fail; j++) {
3801 const char *rule = ref_rev_parse_rules[j];
3802 char refname[PATH_MAX];
3803
3804 /* skip matched rule */
3805 if (i == j)
3806 continue;
3807
3808 /*
3809 * the short name is ambiguous, if it resolves
3810 * (with this previous rule) to a valid ref
3811 * read_ref() returns 0 on success
3812 */
3813 mksnpath(refname, sizeof(refname),
3814 rule, short_name_len, short_name);
3815 if (ref_exists(refname))
3816 break;
3817 }
3818
3819 /*
3820 * short name is non-ambiguous if all previous rules
3821 * haven't resolved to a valid ref
3822 */
3823 if (j == rules_to_fail)
3824 return short_name;
3825 }
3826
3827 free(short_name);
3828 return xstrdup(refname);
3829 }
3830
3831 static struct string_list *hide_refs;
3832
3833 int parse_hide_refs_config(const char *var, const char *value, const char *section)
3834 {
3835 if (!strcmp("transfer.hiderefs", var) ||
3836 /* NEEDSWORK: use parse_config_key() once both are merged */
3837 (starts_with(var, section) && var[strlen(section)] == '.' &&
3838 !strcmp(var + strlen(section), ".hiderefs"))) {
3839 char *ref;
3840 int len;
3841
3842 if (!value)
3843 return config_error_nonbool(var);
3844 ref = xstrdup(value);
3845 len = strlen(ref);
3846 while (len && ref[len - 1] == '/')
3847 ref[--len] = '\0';
3848 if (!hide_refs) {
3849 hide_refs = xcalloc(1, sizeof(*hide_refs));
3850 hide_refs->strdup_strings = 1;
3851 }
3852 string_list_append(hide_refs, ref);
3853 }
3854 return 0;
3855 }
3856
3857 int ref_is_hidden(const char *refname)
3858 {
3859 struct string_list_item *item;
3860
3861 if (!hide_refs)
3862 return 0;
3863 for_each_string_list_item(item, hide_refs) {
3864 int len;
3865 if (!starts_with(refname, item->string))
3866 continue;
3867 len = strlen(item->string);
3868 if (!refname[len] || refname[len] == '/')
3869 return 1;
3870 }
3871 return 0;
3872 }