Merge branch 'maint'
[git] / refs.c
1 #include "cache.h"
2 #include "refs.h"
3 #include "object.h"
4 #include "tag.h"
5 #include "dir.h"
6
7 /* ISSYMREF=01 and ISPACKED=02 are public interfaces */
8 #define REF_KNOWS_PEELED 04
9
10 struct ref_list {
11         struct ref_list *next;
12         unsigned char flag; /* ISSYMREF? ISPACKED? */
13         unsigned char sha1[20];
14         unsigned char peeled[20];
15         char name[FLEX_ARRAY];
16 };
17
18 static const char *parse_ref_line(char *line, unsigned char *sha1)
19 {
20         /*
21          * 42: the answer to everything.
22          *
23          * In this case, it happens to be the answer to
24          *  40 (length of sha1 hex representation)
25          *  +1 (space in between hex and name)
26          *  +1 (newline at the end of the line)
27          */
28         int len = strlen(line) - 42;
29
30         if (len <= 0)
31                 return NULL;
32         if (get_sha1_hex(line, sha1) < 0)
33                 return NULL;
34         if (!isspace(line[40]))
35                 return NULL;
36         line += 41;
37         if (isspace(*line))
38                 return NULL;
39         if (line[len] != '\n')
40                 return NULL;
41         line[len] = 0;
42
43         return line;
44 }
45
46 static struct ref_list *add_ref(const char *name, const unsigned char *sha1,
47                                 int flag, struct ref_list *list,
48                                 struct ref_list **new_entry)
49 {
50         int len;
51         struct ref_list *entry;
52
53         /* Allocate it and add it in.. */
54         len = strlen(name) + 1;
55         entry = xmalloc(sizeof(struct ref_list) + len);
56         hashcpy(entry->sha1, sha1);
57         hashclr(entry->peeled);
58         memcpy(entry->name, name, len);
59         entry->flag = flag;
60         entry->next = list;
61         if (new_entry)
62                 *new_entry = entry;
63         return entry;
64 }
65
66 /* merge sort the ref list */
67 static struct ref_list *sort_ref_list(struct ref_list *list)
68 {
69         int psize, qsize, last_merge_count, cmp;
70         struct ref_list *p, *q, *l, *e;
71         struct ref_list *new_list = list;
72         int k = 1;
73         int merge_count = 0;
74
75         if (!list)
76                 return list;
77
78         do {
79                 last_merge_count = merge_count;
80                 merge_count = 0;
81
82                 psize = 0;
83
84                 p = new_list;
85                 q = new_list;
86                 new_list = NULL;
87                 l = NULL;
88
89                 while (p) {
90                         merge_count++;
91
92                         while (psize < k && q->next) {
93                                 q = q->next;
94                                 psize++;
95                         }
96                         qsize = k;
97
98                         while ((psize > 0) || (qsize > 0 && q)) {
99                                 if (qsize == 0 || !q) {
100                                         e = p;
101                                         p = p->next;
102                                         psize--;
103                                 } else if (psize == 0) {
104                                         e = q;
105                                         q = q->next;
106                                         qsize--;
107                                 } else {
108                                         cmp = strcmp(q->name, p->name);
109                                         if (cmp < 0) {
110                                                 e = q;
111                                                 q = q->next;
112                                                 qsize--;
113                                         } else if (cmp > 0) {
114                                                 e = p;
115                                                 p = p->next;
116                                                 psize--;
117                                         } else {
118                                                 if (hashcmp(q->sha1, p->sha1))
119                                                         die("Duplicated ref, and SHA1s don't match: %s",
120                                                             q->name);
121                                                 warning("Duplicated ref: %s", q->name);
122                                                 e = q;
123                                                 q = q->next;
124                                                 qsize--;
125                                                 free(e);
126                                                 e = p;
127                                                 p = p->next;
128                                                 psize--;
129                                         }
130                                 }
131
132                                 e->next = NULL;
133
134                                 if (l)
135                                         l->next = e;
136                                 if (!new_list)
137                                         new_list = e;
138                                 l = e;
139                         }
140
141                         p = q;
142                 };
143
144                 k = k * 2;
145         } while ((last_merge_count != merge_count) || (last_merge_count != 1));
146
147         return new_list;
148 }
149
150 /*
151  * Future: need to be in "struct repository"
152  * when doing a full libification.
153  */
154 static struct cached_refs {
155         char did_loose;
156         char did_packed;
157         struct ref_list *loose;
158         struct ref_list *packed;
159 } cached_refs;
160 static struct ref_list *current_ref;
161
162 static struct ref_list *extra_refs;
163
164 static void free_ref_list(struct ref_list *list)
165 {
166         struct ref_list *next;
167         for ( ; list; list = next) {
168                 next = list->next;
169                 free(list);
170         }
171 }
172
173 static void invalidate_cached_refs(void)
174 {
175         struct cached_refs *ca = &cached_refs;
176
177         if (ca->did_loose && ca->loose)
178                 free_ref_list(ca->loose);
179         if (ca->did_packed && ca->packed)
180                 free_ref_list(ca->packed);
181         ca->loose = ca->packed = NULL;
182         ca->did_loose = ca->did_packed = 0;
183 }
184
185 static void read_packed_refs(FILE *f, struct cached_refs *cached_refs)
186 {
187         struct ref_list *list = NULL;
188         struct ref_list *last = NULL;
189         char refline[PATH_MAX];
190         int flag = REF_ISPACKED;
191
192         while (fgets(refline, sizeof(refline), f)) {
193                 unsigned char sha1[20];
194                 const char *name;
195                 static const char header[] = "# pack-refs with:";
196
197                 if (!strncmp(refline, header, sizeof(header)-1)) {
198                         const char *traits = refline + sizeof(header) - 1;
199                         if (strstr(traits, " peeled "))
200                                 flag |= REF_KNOWS_PEELED;
201                         /* perhaps other traits later as well */
202                         continue;
203                 }
204
205                 name = parse_ref_line(refline, sha1);
206                 if (name) {
207                         list = add_ref(name, sha1, flag, list, &last);
208                         continue;
209                 }
210                 if (last &&
211                     refline[0] == '^' &&
212                     strlen(refline) == 42 &&
213                     refline[41] == '\n' &&
214                     !get_sha1_hex(refline + 1, sha1))
215                         hashcpy(last->peeled, sha1);
216         }
217         cached_refs->packed = sort_ref_list(list);
218 }
219
220 void add_extra_ref(const char *name, const unsigned char *sha1, int flag)
221 {
222         extra_refs = add_ref(name, sha1, flag, extra_refs, NULL);
223 }
224
225 void clear_extra_refs(void)
226 {
227         free_ref_list(extra_refs);
228         extra_refs = NULL;
229 }
230
231 static struct ref_list *get_packed_refs(void)
232 {
233         if (!cached_refs.did_packed) {
234                 FILE *f = fopen(git_path("packed-refs"), "r");
235                 cached_refs.packed = NULL;
236                 if (f) {
237                         read_packed_refs(f, &cached_refs);
238                         fclose(f);
239                 }
240                 cached_refs.did_packed = 1;
241         }
242         return cached_refs.packed;
243 }
244
245 static struct ref_list *get_ref_dir(const char *base, struct ref_list *list)
246 {
247         DIR *dir = opendir(git_path("%s", base));
248
249         if (dir) {
250                 struct dirent *de;
251                 int baselen = strlen(base);
252                 char *ref = xmalloc(baselen + 257);
253
254                 memcpy(ref, base, baselen);
255                 if (baselen && base[baselen-1] != '/')
256                         ref[baselen++] = '/';
257
258                 while ((de = readdir(dir)) != NULL) {
259                         unsigned char sha1[20];
260                         struct stat st;
261                         int flag;
262                         int namelen;
263
264                         if (de->d_name[0] == '.')
265                                 continue;
266                         namelen = strlen(de->d_name);
267                         if (namelen > 255)
268                                 continue;
269                         if (has_extension(de->d_name, ".lock"))
270                                 continue;
271                         memcpy(ref + baselen, de->d_name, namelen+1);
272                         if (stat(git_path("%s", ref), &st) < 0)
273                                 continue;
274                         if (S_ISDIR(st.st_mode)) {
275                                 list = get_ref_dir(ref, list);
276                                 continue;
277                         }
278                         if (!resolve_ref(ref, sha1, 1, &flag)) {
279                                 error("%s points nowhere!", ref);
280                                 continue;
281                         }
282                         list = add_ref(ref, sha1, flag, list, NULL);
283                 }
284                 free(ref);
285                 closedir(dir);
286         }
287         return sort_ref_list(list);
288 }
289
290 static struct ref_list *get_loose_refs(void)
291 {
292         if (!cached_refs.did_loose) {
293                 cached_refs.loose = get_ref_dir("refs", NULL);
294                 cached_refs.did_loose = 1;
295         }
296         return cached_refs.loose;
297 }
298
299 /* We allow "recursive" symbolic refs. Only within reason, though */
300 #define MAXDEPTH 5
301 #define MAXREFLEN (1024)
302
303 static int resolve_gitlink_packed_ref(char *name, int pathlen, const char *refname, unsigned char *result)
304 {
305         FILE *f;
306         struct cached_refs refs;
307         struct ref_list *ref;
308         int retval;
309
310         strcpy(name + pathlen, "packed-refs");
311         f = fopen(name, "r");
312         if (!f)
313                 return -1;
314         read_packed_refs(f, &refs);
315         fclose(f);
316         ref = refs.packed;
317         retval = -1;
318         while (ref) {
319                 if (!strcmp(ref->name, refname)) {
320                         retval = 0;
321                         memcpy(result, ref->sha1, 20);
322                         break;
323                 }
324                 ref = ref->next;
325         }
326         free_ref_list(refs.packed);
327         return retval;
328 }
329
330 static int resolve_gitlink_ref_recursive(char *name, int pathlen, const char *refname, unsigned char *result, int recursion)
331 {
332         int fd, len = strlen(refname);
333         char buffer[128], *p;
334
335         if (recursion > MAXDEPTH || len > MAXREFLEN)
336                 return -1;
337         memcpy(name + pathlen, refname, len+1);
338         fd = open(name, O_RDONLY);
339         if (fd < 0)
340                 return resolve_gitlink_packed_ref(name, pathlen, refname, result);
341
342         len = read(fd, buffer, sizeof(buffer)-1);
343         close(fd);
344         if (len < 0)
345                 return -1;
346         while (len && isspace(buffer[len-1]))
347                 len--;
348         buffer[len] = 0;
349
350         /* Was it a detached head or an old-fashioned symlink? */
351         if (!get_sha1_hex(buffer, result))
352                 return 0;
353
354         /* Symref? */
355         if (strncmp(buffer, "ref:", 4))
356                 return -1;
357         p = buffer + 4;
358         while (isspace(*p))
359                 p++;
360
361         return resolve_gitlink_ref_recursive(name, pathlen, p, result, recursion+1);
362 }
363
364 int resolve_gitlink_ref(const char *path, const char *refname, unsigned char *result)
365 {
366         int len = strlen(path), retval;
367         char *gitdir;
368         const char *tmp;
369
370         while (len && path[len-1] == '/')
371                 len--;
372         if (!len)
373                 return -1;
374         gitdir = xmalloc(len + MAXREFLEN + 8);
375         memcpy(gitdir, path, len);
376         memcpy(gitdir + len, "/.git", 6);
377         len += 5;
378
379         tmp = read_gitfile_gently(gitdir);
380         if (tmp) {
381                 free(gitdir);
382                 len = strlen(tmp);
383                 gitdir = xmalloc(len + MAXREFLEN + 3);
384                 memcpy(gitdir, tmp, len);
385         }
386         gitdir[len] = '/';
387         gitdir[++len] = '\0';
388         retval = resolve_gitlink_ref_recursive(gitdir, len, refname, result, 0);
389         free(gitdir);
390         return retval;
391 }
392
393 /*
394  * If the "reading" argument is set, this function finds out what _object_
395  * the ref points at by "reading" the ref.  The ref, if it is not symbolic,
396  * has to exist, and if it is symbolic, it has to point at an existing ref,
397  * because the "read" goes through the symref to the ref it points at.
398  *
399  * The access that is not "reading" may often be "writing", but does not
400  * have to; it can be merely checking _where it leads to_. If it is a
401  * prelude to "writing" to the ref, a write to a symref that points at
402  * yet-to-be-born ref will create the real ref pointed by the symref.
403  * reading=0 allows the caller to check where such a symref leads to.
404  */
405 const char *resolve_ref(const char *ref, unsigned char *sha1, int reading, int *flag)
406 {
407         int depth = MAXDEPTH;
408         ssize_t len;
409         char buffer[256];
410         static char ref_buffer[256];
411
412         if (flag)
413                 *flag = 0;
414
415         for (;;) {
416                 const char *path = git_path("%s", ref);
417                 struct stat st;
418                 char *buf;
419                 int fd;
420
421                 if (--depth < 0)
422                         return NULL;
423
424                 /* Special case: non-existing file. */
425                 if (lstat(path, &st) < 0) {
426                         struct ref_list *list = get_packed_refs();
427                         while (list) {
428                                 if (!strcmp(ref, list->name)) {
429                                         hashcpy(sha1, list->sha1);
430                                         if (flag)
431                                                 *flag |= REF_ISPACKED;
432                                         return ref;
433                                 }
434                                 list = list->next;
435                         }
436                         if (reading || errno != ENOENT)
437                                 return NULL;
438                         hashclr(sha1);
439                         return ref;
440                 }
441
442                 /* Follow "normalized" - ie "refs/.." symlinks by hand */
443                 if (S_ISLNK(st.st_mode)) {
444                         len = readlink(path, buffer, sizeof(buffer)-1);
445                         if (len >= 5 && !memcmp("refs/", buffer, 5)) {
446                                 buffer[len] = 0;
447                                 strcpy(ref_buffer, buffer);
448                                 ref = ref_buffer;
449                                 if (flag)
450                                         *flag |= REF_ISSYMREF;
451                                 continue;
452                         }
453                 }
454
455                 /* Is it a directory? */
456                 if (S_ISDIR(st.st_mode)) {
457                         errno = EISDIR;
458                         return NULL;
459                 }
460
461                 /*
462                  * Anything else, just open it and try to use it as
463                  * a ref
464                  */
465                 fd = open(path, O_RDONLY);
466                 if (fd < 0)
467                         return NULL;
468                 len = read_in_full(fd, buffer, sizeof(buffer)-1);
469                 close(fd);
470
471                 /*
472                  * Is it a symbolic ref?
473                  */
474                 if (len < 4 || memcmp("ref:", buffer, 4))
475                         break;
476                 buf = buffer + 4;
477                 len -= 4;
478                 while (len && isspace(*buf))
479                         buf++, len--;
480                 while (len && isspace(buf[len-1]))
481                         len--;
482                 buf[len] = 0;
483                 memcpy(ref_buffer, buf, len + 1);
484                 ref = ref_buffer;
485                 if (flag)
486                         *flag |= REF_ISSYMREF;
487         }
488         if (len < 40 || get_sha1_hex(buffer, sha1))
489                 return NULL;
490         return ref;
491 }
492
493 int read_ref(const char *ref, unsigned char *sha1)
494 {
495         if (resolve_ref(ref, sha1, 1, NULL))
496                 return 0;
497         return -1;
498 }
499
500 static int do_one_ref(const char *base, each_ref_fn fn, int trim,
501                       void *cb_data, struct ref_list *entry)
502 {
503         if (strncmp(base, entry->name, trim))
504                 return 0;
505         if (is_null_sha1(entry->sha1))
506                 return 0;
507         if (!has_sha1_file(entry->sha1)) {
508                 error("%s does not point to a valid object!", entry->name);
509                 return 0;
510         }
511         current_ref = entry;
512         return fn(entry->name + trim, entry->sha1, entry->flag, cb_data);
513 }
514
515 int peel_ref(const char *ref, unsigned char *sha1)
516 {
517         int flag;
518         unsigned char base[20];
519         struct object *o;
520
521         if (current_ref && (current_ref->name == ref
522                 || !strcmp(current_ref->name, ref))) {
523                 if (current_ref->flag & REF_KNOWS_PEELED) {
524                         hashcpy(sha1, current_ref->peeled);
525                         return 0;
526                 }
527                 hashcpy(base, current_ref->sha1);
528                 goto fallback;
529         }
530
531         if (!resolve_ref(ref, base, 1, &flag))
532                 return -1;
533
534         if ((flag & REF_ISPACKED)) {
535                 struct ref_list *list = get_packed_refs();
536
537                 while (list) {
538                         if (!strcmp(list->name, ref)) {
539                                 if (list->flag & REF_KNOWS_PEELED) {
540                                         hashcpy(sha1, list->peeled);
541                                         return 0;
542                                 }
543                                 /* older pack-refs did not leave peeled ones */
544                                 break;
545                         }
546                         list = list->next;
547                 }
548         }
549
550 fallback:
551         o = parse_object(base);
552         if (o && o->type == OBJ_TAG) {
553                 o = deref_tag(o, ref, 0);
554                 if (o) {
555                         hashcpy(sha1, o->sha1);
556                         return 0;
557                 }
558         }
559         return -1;
560 }
561
562 static int do_for_each_ref(const char *base, each_ref_fn fn, int trim,
563                            void *cb_data)
564 {
565         int retval = 0;
566         struct ref_list *packed = get_packed_refs();
567         struct ref_list *loose = get_loose_refs();
568
569         struct ref_list *extra;
570
571         for (extra = extra_refs; extra; extra = extra->next)
572                 retval = do_one_ref(base, fn, trim, cb_data, extra);
573
574         while (packed && loose) {
575                 struct ref_list *entry;
576                 int cmp = strcmp(packed->name, loose->name);
577                 if (!cmp) {
578                         packed = packed->next;
579                         continue;
580                 }
581                 if (cmp > 0) {
582                         entry = loose;
583                         loose = loose->next;
584                 } else {
585                         entry = packed;
586                         packed = packed->next;
587                 }
588                 retval = do_one_ref(base, fn, trim, cb_data, entry);
589                 if (retval)
590                         goto end_each;
591         }
592
593         for (packed = packed ? packed : loose; packed; packed = packed->next) {
594                 retval = do_one_ref(base, fn, trim, cb_data, packed);
595                 if (retval)
596                         goto end_each;
597         }
598
599 end_each:
600         current_ref = NULL;
601         return retval;
602 }
603
604 int head_ref(each_ref_fn fn, void *cb_data)
605 {
606         unsigned char sha1[20];
607         int flag;
608
609         if (resolve_ref("HEAD", sha1, 1, &flag))
610                 return fn("HEAD", sha1, flag, cb_data);
611         return 0;
612 }
613
614 int for_each_ref(each_ref_fn fn, void *cb_data)
615 {
616         return do_for_each_ref("refs/", fn, 0, cb_data);
617 }
618
619 int for_each_tag_ref(each_ref_fn fn, void *cb_data)
620 {
621         return do_for_each_ref("refs/tags/", fn, 10, cb_data);
622 }
623
624 int for_each_branch_ref(each_ref_fn fn, void *cb_data)
625 {
626         return do_for_each_ref("refs/heads/", fn, 11, cb_data);
627 }
628
629 int for_each_remote_ref(each_ref_fn fn, void *cb_data)
630 {
631         return do_for_each_ref("refs/remotes/", fn, 13, cb_data);
632 }
633
634 /*
635  * Make sure "ref" is something reasonable to have under ".git/refs/";
636  * We do not like it if:
637  *
638  * - any path component of it begins with ".", or
639  * - it has double dots "..", or
640  * - it has ASCII control character, "~", "^", ":" or SP, anywhere, or
641  * - it ends with a "/".
642  */
643
644 static inline int bad_ref_char(int ch)
645 {
646         if (((unsigned) ch) <= ' ' ||
647             ch == '~' || ch == '^' || ch == ':')
648                 return 1;
649         /* 2.13 Pattern Matching Notation */
650         if (ch == '?' || ch == '[') /* Unsupported */
651                 return 1;
652         if (ch == '*') /* Supported at the end */
653                 return 2;
654         return 0;
655 }
656
657 int check_ref_format(const char *ref)
658 {
659         int ch, level, bad_type;
660         const char *cp = ref;
661
662         level = 0;
663         while (1) {
664                 while ((ch = *cp++) == '/')
665                         ; /* tolerate duplicated slashes */
666                 if (!ch)
667                         /* should not end with slashes */
668                         return CHECK_REF_FORMAT_ERROR;
669
670                 /* we are at the beginning of the path component */
671                 if (ch == '.')
672                         return CHECK_REF_FORMAT_ERROR;
673                 bad_type = bad_ref_char(ch);
674                 if (bad_type) {
675                         return (bad_type == 2 && !*cp)
676                                 ? CHECK_REF_FORMAT_WILDCARD
677                                 : CHECK_REF_FORMAT_ERROR;
678                 }
679
680                 /* scan the rest of the path component */
681                 while ((ch = *cp++) != 0) {
682                         bad_type = bad_ref_char(ch);
683                         if (bad_type) {
684                                 return (bad_type == 2 && !*cp)
685                                         ? CHECK_REF_FORMAT_WILDCARD
686                                         : CHECK_REF_FORMAT_ERROR;
687                         }
688                         if (ch == '/')
689                                 break;
690                         if (ch == '.' && *cp == '.')
691                                 return CHECK_REF_FORMAT_ERROR;
692                 }
693                 level++;
694                 if (!ch) {
695                         if (level < 2)
696                                 return CHECK_REF_FORMAT_ONELEVEL;
697                         return CHECK_REF_FORMAT_OK;
698                 }
699         }
700 }
701
702 const char *ref_rev_parse_rules[] = {
703         "%.*s",
704         "refs/%.*s",
705         "refs/tags/%.*s",
706         "refs/heads/%.*s",
707         "refs/remotes/%.*s",
708         "refs/remotes/%.*s/HEAD",
709         NULL
710 };
711
712 const char *ref_fetch_rules[] = {
713         "%.*s",
714         "refs/%.*s",
715         "refs/heads/%.*s",
716         NULL
717 };
718
719 int refname_match(const char *abbrev_name, const char *full_name, const char **rules)
720 {
721         const char **p;
722         const int abbrev_name_len = strlen(abbrev_name);
723
724         for (p = rules; *p; p++) {
725                 if (!strcmp(full_name, mkpath(*p, abbrev_name_len, abbrev_name))) {
726                         return 1;
727                 }
728         }
729
730         return 0;
731 }
732
733 static struct ref_lock *verify_lock(struct ref_lock *lock,
734         const unsigned char *old_sha1, int mustexist)
735 {
736         if (!resolve_ref(lock->ref_name, lock->old_sha1, mustexist, NULL)) {
737                 error("Can't verify ref %s", lock->ref_name);
738                 unlock_ref(lock);
739                 return NULL;
740         }
741         if (hashcmp(lock->old_sha1, old_sha1)) {
742                 error("Ref %s is at %s but expected %s", lock->ref_name,
743                         sha1_to_hex(lock->old_sha1), sha1_to_hex(old_sha1));
744                 unlock_ref(lock);
745                 return NULL;
746         }
747         return lock;
748 }
749
750 static int remove_empty_directories(const char *file)
751 {
752         /* we want to create a file but there is a directory there;
753          * if that is an empty directory (or a directory that contains
754          * only empty directories), remove them.
755          */
756         struct strbuf path;
757         int result;
758
759         strbuf_init(&path, 20);
760         strbuf_addstr(&path, file);
761
762         result = remove_dir_recursively(&path, 1);
763
764         strbuf_release(&path);
765
766         return result;
767 }
768
769 static int is_refname_available(const char *ref, const char *oldref,
770                                 struct ref_list *list, int quiet)
771 {
772         int namlen = strlen(ref); /* e.g. 'foo/bar' */
773         while (list) {
774                 /* list->name could be 'foo' or 'foo/bar/baz' */
775                 if (!oldref || strcmp(oldref, list->name)) {
776                         int len = strlen(list->name);
777                         int cmplen = (namlen < len) ? namlen : len;
778                         const char *lead = (namlen < len) ? list->name : ref;
779                         if (!strncmp(ref, list->name, cmplen) &&
780                             lead[cmplen] == '/') {
781                                 if (!quiet)
782                                         error("'%s' exists; cannot create '%s'",
783                                               list->name, ref);
784                                 return 0;
785                         }
786                 }
787                 list = list->next;
788         }
789         return 1;
790 }
791
792 static struct ref_lock *lock_ref_sha1_basic(const char *ref, const unsigned char *old_sha1, int flags, int *type_p)
793 {
794         char *ref_file;
795         const char *orig_ref = ref;
796         struct ref_lock *lock;
797         struct stat st;
798         int last_errno = 0;
799         int type;
800         int mustexist = (old_sha1 && !is_null_sha1(old_sha1));
801
802         lock = xcalloc(1, sizeof(struct ref_lock));
803         lock->lock_fd = -1;
804
805         ref = resolve_ref(ref, lock->old_sha1, mustexist, &type);
806         if (!ref && errno == EISDIR) {
807                 /* we are trying to lock foo but we used to
808                  * have foo/bar which now does not exist;
809                  * it is normal for the empty directory 'foo'
810                  * to remain.
811                  */
812                 ref_file = git_path("%s", orig_ref);
813                 if (remove_empty_directories(ref_file)) {
814                         last_errno = errno;
815                         error("there are still refs under '%s'", orig_ref);
816                         goto error_return;
817                 }
818                 ref = resolve_ref(orig_ref, lock->old_sha1, mustexist, &type);
819         }
820         if (type_p)
821             *type_p = type;
822         if (!ref) {
823                 last_errno = errno;
824                 error("unable to resolve reference %s: %s",
825                         orig_ref, strerror(errno));
826                 goto error_return;
827         }
828         /* When the ref did not exist and we are creating it,
829          * make sure there is no existing ref that is packed
830          * whose name begins with our refname, nor a ref whose
831          * name is a proper prefix of our refname.
832          */
833         if (is_null_sha1(lock->old_sha1) &&
834             !is_refname_available(ref, NULL, get_packed_refs(), 0))
835                 goto error_return;
836
837         lock->lk = xcalloc(1, sizeof(struct lock_file));
838
839         if (flags & REF_NODEREF)
840                 ref = orig_ref;
841         lock->ref_name = xstrdup(ref);
842         lock->orig_ref_name = xstrdup(orig_ref);
843         ref_file = git_path("%s", ref);
844         if (lstat(ref_file, &st) && errno == ENOENT)
845                 lock->force_write = 1;
846         if ((flags & REF_NODEREF) && (type & REF_ISSYMREF))
847                 lock->force_write = 1;
848
849         if (safe_create_leading_directories(ref_file)) {
850                 last_errno = errno;
851                 error("unable to create directory for %s", ref_file);
852                 goto error_return;
853         }
854         lock->lock_fd = hold_lock_file_for_update(lock->lk, ref_file, 1);
855
856         return old_sha1 ? verify_lock(lock, old_sha1, mustexist) : lock;
857
858  error_return:
859         unlock_ref(lock);
860         errno = last_errno;
861         return NULL;
862 }
863
864 struct ref_lock *lock_ref_sha1(const char *ref, const unsigned char *old_sha1)
865 {
866         char refpath[PATH_MAX];
867         if (check_ref_format(ref))
868                 return NULL;
869         strcpy(refpath, mkpath("refs/%s", ref));
870         return lock_ref_sha1_basic(refpath, old_sha1, 0, NULL);
871 }
872
873 struct ref_lock *lock_any_ref_for_update(const char *ref, const unsigned char *old_sha1, int flags)
874 {
875         switch (check_ref_format(ref)) {
876         default:
877                 return NULL;
878         case 0:
879         case CHECK_REF_FORMAT_ONELEVEL:
880                 return lock_ref_sha1_basic(ref, old_sha1, flags, NULL);
881         }
882 }
883
884 static struct lock_file packlock;
885
886 static int repack_without_ref(const char *refname)
887 {
888         struct ref_list *list, *packed_ref_list;
889         int fd;
890         int found = 0;
891
892         packed_ref_list = get_packed_refs();
893         for (list = packed_ref_list; list; list = list->next) {
894                 if (!strcmp(refname, list->name)) {
895                         found = 1;
896                         break;
897                 }
898         }
899         if (!found)
900                 return 0;
901         fd = hold_lock_file_for_update(&packlock, git_path("packed-refs"), 0);
902         if (fd < 0)
903                 return error("cannot delete '%s' from packed refs", refname);
904
905         for (list = packed_ref_list; list; list = list->next) {
906                 char line[PATH_MAX + 100];
907                 int len;
908
909                 if (!strcmp(refname, list->name))
910                         continue;
911                 len = snprintf(line, sizeof(line), "%s %s\n",
912                                sha1_to_hex(list->sha1), list->name);
913                 /* this should not happen but just being defensive */
914                 if (len > sizeof(line))
915                         die("too long a refname '%s'", list->name);
916                 write_or_die(fd, line, len);
917         }
918         return commit_lock_file(&packlock);
919 }
920
921 int delete_ref(const char *refname, const unsigned char *sha1)
922 {
923         struct ref_lock *lock;
924         int err, i, ret = 0, flag = 0;
925
926         lock = lock_ref_sha1_basic(refname, sha1, 0, &flag);
927         if (!lock)
928                 return 1;
929         if (!(flag & REF_ISPACKED)) {
930                 /* loose */
931                 i = strlen(lock->lk->filename) - 5; /* .lock */
932                 lock->lk->filename[i] = 0;
933                 err = unlink(lock->lk->filename);
934                 if (err && errno != ENOENT) {
935                         ret = 1;
936                         error("unlink(%s) failed: %s",
937                               lock->lk->filename, strerror(errno));
938                 }
939                 lock->lk->filename[i] = '.';
940         }
941         /* removing the loose one could have resurrected an earlier
942          * packed one.  Also, if it was not loose we need to repack
943          * without it.
944          */
945         ret |= repack_without_ref(refname);
946
947         err = unlink(git_path("logs/%s", lock->ref_name));
948         if (err && errno != ENOENT)
949                 fprintf(stderr, "warning: unlink(%s) failed: %s",
950                         git_path("logs/%s", lock->ref_name), strerror(errno));
951         invalidate_cached_refs();
952         unlock_ref(lock);
953         return ret;
954 }
955
956 int rename_ref(const char *oldref, const char *newref, const char *logmsg)
957 {
958         static const char renamed_ref[] = "RENAMED-REF";
959         unsigned char sha1[20], orig_sha1[20];
960         int flag = 0, logmoved = 0;
961         struct ref_lock *lock;
962         struct stat loginfo;
963         int log = !lstat(git_path("logs/%s", oldref), &loginfo);
964
965         if (S_ISLNK(loginfo.st_mode))
966                 return error("reflog for %s is a symlink", oldref);
967
968         if (!resolve_ref(oldref, orig_sha1, 1, &flag))
969                 return error("refname %s not found", oldref);
970
971         if (!is_refname_available(newref, oldref, get_packed_refs(), 0))
972                 return 1;
973
974         if (!is_refname_available(newref, oldref, get_loose_refs(), 0))
975                 return 1;
976
977         lock = lock_ref_sha1_basic(renamed_ref, NULL, 0, NULL);
978         if (!lock)
979                 return error("unable to lock %s", renamed_ref);
980         lock->force_write = 1;
981         if (write_ref_sha1(lock, orig_sha1, logmsg))
982                 return error("unable to save current sha1 in %s", renamed_ref);
983
984         if (log && rename(git_path("logs/%s", oldref), git_path("tmp-renamed-log")))
985                 return error("unable to move logfile logs/%s to tmp-renamed-log: %s",
986                         oldref, strerror(errno));
987
988         if (delete_ref(oldref, orig_sha1)) {
989                 error("unable to delete old %s", oldref);
990                 goto rollback;
991         }
992
993         if (resolve_ref(newref, sha1, 1, &flag) && delete_ref(newref, sha1)) {
994                 if (errno==EISDIR) {
995                         if (remove_empty_directories(git_path("%s", newref))) {
996                                 error("Directory not empty: %s", newref);
997                                 goto rollback;
998                         }
999                 } else {
1000                         error("unable to delete existing %s", newref);
1001                         goto rollback;
1002                 }
1003         }
1004
1005         if (log && safe_create_leading_directories(git_path("logs/%s", newref))) {
1006                 error("unable to create directory for %s", newref);
1007                 goto rollback;
1008         }
1009
1010  retry:
1011         if (log && rename(git_path("tmp-renamed-log"), git_path("logs/%s", newref))) {
1012                 if (errno==EISDIR || errno==ENOTDIR) {
1013                         /*
1014                          * rename(a, b) when b is an existing
1015                          * directory ought to result in ISDIR, but
1016                          * Solaris 5.8 gives ENOTDIR.  Sheesh.
1017                          */
1018                         if (remove_empty_directories(git_path("logs/%s", newref))) {
1019                                 error("Directory not empty: logs/%s", newref);
1020                                 goto rollback;
1021                         }
1022                         goto retry;
1023                 } else {
1024                         error("unable to move logfile tmp-renamed-log to logs/%s: %s",
1025                                 newref, strerror(errno));
1026                         goto rollback;
1027                 }
1028         }
1029         logmoved = log;
1030
1031         lock = lock_ref_sha1_basic(newref, NULL, 0, NULL);
1032         if (!lock) {
1033                 error("unable to lock %s for update", newref);
1034                 goto rollback;
1035         }
1036
1037         lock->force_write = 1;
1038         hashcpy(lock->old_sha1, orig_sha1);
1039         if (write_ref_sha1(lock, orig_sha1, logmsg)) {
1040                 error("unable to write current sha1 into %s", newref);
1041                 goto rollback;
1042         }
1043
1044         return 0;
1045
1046  rollback:
1047         lock = lock_ref_sha1_basic(oldref, NULL, 0, NULL);
1048         if (!lock) {
1049                 error("unable to lock %s for rollback", oldref);
1050                 goto rollbacklog;
1051         }
1052
1053         lock->force_write = 1;
1054         flag = log_all_ref_updates;
1055         log_all_ref_updates = 0;
1056         if (write_ref_sha1(lock, orig_sha1, NULL))
1057                 error("unable to write current sha1 into %s", oldref);
1058         log_all_ref_updates = flag;
1059
1060  rollbacklog:
1061         if (logmoved && rename(git_path("logs/%s", newref), git_path("logs/%s", oldref)))
1062                 error("unable to restore logfile %s from %s: %s",
1063                         oldref, newref, strerror(errno));
1064         if (!logmoved && log &&
1065             rename(git_path("tmp-renamed-log"), git_path("logs/%s", oldref)))
1066                 error("unable to restore logfile %s from tmp-renamed-log: %s",
1067                         oldref, strerror(errno));
1068
1069         return 1;
1070 }
1071
1072 int close_ref(struct ref_lock *lock)
1073 {
1074         if (close_lock_file(lock->lk))
1075                 return -1;
1076         lock->lock_fd = -1;
1077         return 0;
1078 }
1079
1080 int commit_ref(struct ref_lock *lock)
1081 {
1082         if (commit_lock_file(lock->lk))
1083                 return -1;
1084         lock->lock_fd = -1;
1085         return 0;
1086 }
1087
1088 void unlock_ref(struct ref_lock *lock)
1089 {
1090         /* Do not free lock->lk -- atexit() still looks at them */
1091         if (lock->lk)
1092                 rollback_lock_file(lock->lk);
1093         free(lock->ref_name);
1094         free(lock->orig_ref_name);
1095         free(lock);
1096 }
1097
1098 /*
1099  * copy the reflog message msg to buf, which has been allocated sufficiently
1100  * large, while cleaning up the whitespaces.  Especially, convert LF to space,
1101  * because reflog file is one line per entry.
1102  */
1103 static int copy_msg(char *buf, const char *msg)
1104 {
1105         char *cp = buf;
1106         char c;
1107         int wasspace = 1;
1108
1109         *cp++ = '\t';
1110         while ((c = *msg++)) {
1111                 if (wasspace && isspace(c))
1112                         continue;
1113                 wasspace = isspace(c);
1114                 if (wasspace)
1115                         c = ' ';
1116                 *cp++ = c;
1117         }
1118         while (buf < cp && isspace(cp[-1]))
1119                 cp--;
1120         *cp++ = '\n';
1121         return cp - buf;
1122 }
1123
1124 static int log_ref_write(const char *ref_name, const unsigned char *old_sha1,
1125                          const unsigned char *new_sha1, const char *msg)
1126 {
1127         int logfd, written, oflags = O_APPEND | O_WRONLY;
1128         unsigned maxlen, len;
1129         int msglen;
1130         char *log_file, *logrec;
1131         const char *committer;
1132
1133         if (log_all_ref_updates < 0)
1134                 log_all_ref_updates = !is_bare_repository();
1135
1136         log_file = git_path("logs/%s", ref_name);
1137
1138         if (log_all_ref_updates &&
1139             (!prefixcmp(ref_name, "refs/heads/") ||
1140              !prefixcmp(ref_name, "refs/remotes/") ||
1141              !strcmp(ref_name, "HEAD"))) {
1142                 if (safe_create_leading_directories(log_file) < 0)
1143                         return error("unable to create directory for %s",
1144                                      log_file);
1145                 oflags |= O_CREAT;
1146         }
1147
1148         logfd = open(log_file, oflags, 0666);
1149         if (logfd < 0) {
1150                 if (!(oflags & O_CREAT) && errno == ENOENT)
1151                         return 0;
1152
1153                 if ((oflags & O_CREAT) && errno == EISDIR) {
1154                         if (remove_empty_directories(log_file)) {
1155                                 return error("There are still logs under '%s'",
1156                                              log_file);
1157                         }
1158                         logfd = open(log_file, oflags, 0666);
1159                 }
1160
1161                 if (logfd < 0)
1162                         return error("Unable to append to %s: %s",
1163                                      log_file, strerror(errno));
1164         }
1165
1166         adjust_shared_perm(log_file);
1167
1168         msglen = msg ? strlen(msg) : 0;
1169         committer = git_committer_info(0);
1170         maxlen = strlen(committer) + msglen + 100;
1171         logrec = xmalloc(maxlen);
1172         len = sprintf(logrec, "%s %s %s\n",
1173                       sha1_to_hex(old_sha1),
1174                       sha1_to_hex(new_sha1),
1175                       committer);
1176         if (msglen)
1177                 len += copy_msg(logrec + len - 1, msg) - 1;
1178         written = len <= maxlen ? write_in_full(logfd, logrec, len) : -1;
1179         free(logrec);
1180         if (close(logfd) != 0 || written != len)
1181                 return error("Unable to append to %s", log_file);
1182         return 0;
1183 }
1184
1185 static int is_branch(const char *refname)
1186 {
1187         return !strcmp(refname, "HEAD") || !prefixcmp(refname, "refs/heads/");
1188 }
1189
1190 int write_ref_sha1(struct ref_lock *lock,
1191         const unsigned char *sha1, const char *logmsg)
1192 {
1193         static char term = '\n';
1194         struct object *o;
1195
1196         if (!lock)
1197                 return -1;
1198         if (!lock->force_write && !hashcmp(lock->old_sha1, sha1)) {
1199                 unlock_ref(lock);
1200                 return 0;
1201         }
1202         o = parse_object(sha1);
1203         if (!o) {
1204                 error("Trying to write ref %s with nonexistant object %s",
1205                         lock->ref_name, sha1_to_hex(sha1));
1206                 unlock_ref(lock);
1207                 return -1;
1208         }
1209         if (o->type != OBJ_COMMIT && is_branch(lock->ref_name)) {
1210                 error("Trying to write non-commit object %s to branch %s",
1211                         sha1_to_hex(sha1), lock->ref_name);
1212                 unlock_ref(lock);
1213                 return -1;
1214         }
1215         if (write_in_full(lock->lock_fd, sha1_to_hex(sha1), 40) != 40 ||
1216             write_in_full(lock->lock_fd, &term, 1) != 1
1217                 || close_ref(lock) < 0) {
1218                 error("Couldn't write %s", lock->lk->filename);
1219                 unlock_ref(lock);
1220                 return -1;
1221         }
1222         invalidate_cached_refs();
1223         if (log_ref_write(lock->ref_name, lock->old_sha1, sha1, logmsg) < 0 ||
1224             (strcmp(lock->ref_name, lock->orig_ref_name) &&
1225              log_ref_write(lock->orig_ref_name, lock->old_sha1, sha1, logmsg) < 0)) {
1226                 unlock_ref(lock);
1227                 return -1;
1228         }
1229         if (strcmp(lock->orig_ref_name, "HEAD") != 0) {
1230                 /*
1231                  * Special hack: If a branch is updated directly and HEAD
1232                  * points to it (may happen on the remote side of a push
1233                  * for example) then logically the HEAD reflog should be
1234                  * updated too.
1235                  * A generic solution implies reverse symref information,
1236                  * but finding all symrefs pointing to the given branch
1237                  * would be rather costly for this rare event (the direct
1238                  * update of a branch) to be worth it.  So let's cheat and
1239                  * check with HEAD only which should cover 99% of all usage
1240                  * scenarios (even 100% of the default ones).
1241                  */
1242                 unsigned char head_sha1[20];
1243                 int head_flag;
1244                 const char *head_ref;
1245                 head_ref = resolve_ref("HEAD", head_sha1, 1, &head_flag);
1246                 if (head_ref && (head_flag & REF_ISSYMREF) &&
1247                     !strcmp(head_ref, lock->ref_name))
1248                         log_ref_write("HEAD", lock->old_sha1, sha1, logmsg);
1249         }
1250         if (commit_ref(lock)) {
1251                 error("Couldn't set %s", lock->ref_name);
1252                 unlock_ref(lock);
1253                 return -1;
1254         }
1255         unlock_ref(lock);
1256         return 0;
1257 }
1258
1259 int create_symref(const char *ref_target, const char *refs_heads_master,
1260                   const char *logmsg)
1261 {
1262         const char *lockpath;
1263         char ref[1000];
1264         int fd, len, written;
1265         char *git_HEAD = xstrdup(git_path("%s", ref_target));
1266         unsigned char old_sha1[20], new_sha1[20];
1267
1268         if (logmsg && read_ref(ref_target, old_sha1))
1269                 hashclr(old_sha1);
1270
1271         if (safe_create_leading_directories(git_HEAD) < 0)
1272                 return error("unable to create directory for %s", git_HEAD);
1273
1274 #ifndef NO_SYMLINK_HEAD
1275         if (prefer_symlink_refs) {
1276                 unlink(git_HEAD);
1277                 if (!symlink(refs_heads_master, git_HEAD))
1278                         goto done;
1279                 fprintf(stderr, "no symlink - falling back to symbolic ref\n");
1280         }
1281 #endif
1282
1283         len = snprintf(ref, sizeof(ref), "ref: %s\n", refs_heads_master);
1284         if (sizeof(ref) <= len) {
1285                 error("refname too long: %s", refs_heads_master);
1286                 goto error_free_return;
1287         }
1288         lockpath = mkpath("%s.lock", git_HEAD);
1289         fd = open(lockpath, O_CREAT | O_EXCL | O_WRONLY, 0666);
1290         if (fd < 0) {
1291                 error("Unable to open %s for writing", lockpath);
1292                 goto error_free_return;
1293         }
1294         written = write_in_full(fd, ref, len);
1295         if (close(fd) != 0 || written != len) {
1296                 error("Unable to write to %s", lockpath);
1297                 goto error_unlink_return;
1298         }
1299         if (rename(lockpath, git_HEAD) < 0) {
1300                 error("Unable to create %s", git_HEAD);
1301                 goto error_unlink_return;
1302         }
1303         if (adjust_shared_perm(git_HEAD)) {
1304                 error("Unable to fix permissions on %s", lockpath);
1305         error_unlink_return:
1306                 unlink(lockpath);
1307         error_free_return:
1308                 free(git_HEAD);
1309                 return -1;
1310         }
1311
1312 #ifndef NO_SYMLINK_HEAD
1313         done:
1314 #endif
1315         if (logmsg && !read_ref(refs_heads_master, new_sha1))
1316                 log_ref_write(ref_target, old_sha1, new_sha1, logmsg);
1317
1318         free(git_HEAD);
1319         return 0;
1320 }
1321
1322 static char *ref_msg(const char *line, const char *endp)
1323 {
1324         const char *ep;
1325         line += 82;
1326         ep = memchr(line, '\n', endp - line);
1327         if (!ep)
1328                 ep = endp;
1329         return xmemdupz(line, ep - line);
1330 }
1331
1332 int read_ref_at(const char *ref, unsigned long at_time, int cnt, unsigned char *sha1, char **msg, unsigned long *cutoff_time, int *cutoff_tz, int *cutoff_cnt)
1333 {
1334         const char *logfile, *logdata, *logend, *rec, *lastgt, *lastrec;
1335         char *tz_c;
1336         int logfd, tz, reccnt = 0;
1337         struct stat st;
1338         unsigned long date;
1339         unsigned char logged_sha1[20];
1340         void *log_mapped;
1341         size_t mapsz;
1342
1343         logfile = git_path("logs/%s", ref);
1344         logfd = open(logfile, O_RDONLY, 0);
1345         if (logfd < 0)
1346                 die("Unable to read log %s: %s", logfile, strerror(errno));
1347         fstat(logfd, &st);
1348         if (!st.st_size)
1349                 die("Log %s is empty.", logfile);
1350         mapsz = xsize_t(st.st_size);
1351         log_mapped = xmmap(NULL, mapsz, PROT_READ, MAP_PRIVATE, logfd, 0);
1352         logdata = log_mapped;
1353         close(logfd);
1354
1355         lastrec = NULL;
1356         rec = logend = logdata + st.st_size;
1357         while (logdata < rec) {
1358                 reccnt++;
1359                 if (logdata < rec && *(rec-1) == '\n')
1360                         rec--;
1361                 lastgt = NULL;
1362                 while (logdata < rec && *(rec-1) != '\n') {
1363                         rec--;
1364                         if (*rec == '>')
1365                                 lastgt = rec;
1366                 }
1367                 if (!lastgt)
1368                         die("Log %s is corrupt.", logfile);
1369                 date = strtoul(lastgt + 1, &tz_c, 10);
1370                 if (date <= at_time || cnt == 0) {
1371                         tz = strtoul(tz_c, NULL, 10);
1372                         if (msg)
1373                                 *msg = ref_msg(rec, logend);
1374                         if (cutoff_time)
1375                                 *cutoff_time = date;
1376                         if (cutoff_tz)
1377                                 *cutoff_tz = tz;
1378                         if (cutoff_cnt)
1379                                 *cutoff_cnt = reccnt - 1;
1380                         if (lastrec) {
1381                                 if (get_sha1_hex(lastrec, logged_sha1))
1382                                         die("Log %s is corrupt.", logfile);
1383                                 if (get_sha1_hex(rec + 41, sha1))
1384                                         die("Log %s is corrupt.", logfile);
1385                                 if (hashcmp(logged_sha1, sha1)) {
1386                                         fprintf(stderr,
1387                                                 "warning: Log %s has gap after %s.\n",
1388                                                 logfile, show_date(date, tz, DATE_RFC2822));
1389                                 }
1390                         }
1391                         else if (date == at_time) {
1392                                 if (get_sha1_hex(rec + 41, sha1))
1393                                         die("Log %s is corrupt.", logfile);
1394                         }
1395                         else {
1396                                 if (get_sha1_hex(rec + 41, logged_sha1))
1397                                         die("Log %s is corrupt.", logfile);
1398                                 if (hashcmp(logged_sha1, sha1)) {
1399                                         fprintf(stderr,
1400                                                 "warning: Log %s unexpectedly ended on %s.\n",
1401                                                 logfile, show_date(date, tz, DATE_RFC2822));
1402                                 }
1403                         }
1404                         munmap(log_mapped, mapsz);
1405                         return 0;
1406                 }
1407                 lastrec = rec;
1408                 if (cnt > 0)
1409                         cnt--;
1410         }
1411
1412         rec = logdata;
1413         while (rec < logend && *rec != '>' && *rec != '\n')
1414                 rec++;
1415         if (rec == logend || *rec == '\n')
1416                 die("Log %s is corrupt.", logfile);
1417         date = strtoul(rec + 1, &tz_c, 10);
1418         tz = strtoul(tz_c, NULL, 10);
1419         if (get_sha1_hex(logdata, sha1))
1420                 die("Log %s is corrupt.", logfile);
1421         if (is_null_sha1(sha1)) {
1422                 if (get_sha1_hex(logdata + 41, sha1))
1423                         die("Log %s is corrupt.", logfile);
1424         }
1425         if (msg)
1426                 *msg = ref_msg(logdata, logend);
1427         munmap(log_mapped, mapsz);
1428
1429         if (cutoff_time)
1430                 *cutoff_time = date;
1431         if (cutoff_tz)
1432                 *cutoff_tz = tz;
1433         if (cutoff_cnt)
1434                 *cutoff_cnt = reccnt;
1435         return 1;
1436 }
1437
1438 int for_each_reflog_ent(const char *ref, each_reflog_ent_fn fn, void *cb_data)
1439 {
1440         const char *logfile;
1441         FILE *logfp;
1442         char buf[1024];
1443         int ret = 0;
1444
1445         logfile = git_path("logs/%s", ref);
1446         logfp = fopen(logfile, "r");
1447         if (!logfp)
1448                 return -1;
1449         while (fgets(buf, sizeof(buf), logfp)) {
1450                 unsigned char osha1[20], nsha1[20];
1451                 char *email_end, *message;
1452                 unsigned long timestamp;
1453                 int len, tz;
1454
1455                 /* old SP new SP name <email> SP time TAB msg LF */
1456                 len = strlen(buf);
1457                 if (len < 83 || buf[len-1] != '\n' ||
1458                     get_sha1_hex(buf, osha1) || buf[40] != ' ' ||
1459                     get_sha1_hex(buf + 41, nsha1) || buf[81] != ' ' ||
1460                     !(email_end = strchr(buf + 82, '>')) ||
1461                     email_end[1] != ' ' ||
1462                     !(timestamp = strtoul(email_end + 2, &message, 10)) ||
1463                     !message || message[0] != ' ' ||
1464                     (message[1] != '+' && message[1] != '-') ||
1465                     !isdigit(message[2]) || !isdigit(message[3]) ||
1466                     !isdigit(message[4]) || !isdigit(message[5]))
1467                         continue; /* corrupt? */
1468                 email_end[1] = '\0';
1469                 tz = strtol(message + 1, NULL, 10);
1470                 if (message[6] != '\t')
1471                         message += 6;
1472                 else
1473                         message += 7;
1474                 ret = fn(osha1, nsha1, buf+82, timestamp, tz, message, cb_data);
1475                 if (ret)
1476                         break;
1477         }
1478         fclose(logfp);
1479         return ret;
1480 }
1481
1482 static int do_for_each_reflog(const char *base, each_ref_fn fn, void *cb_data)
1483 {
1484         DIR *dir = opendir(git_path("logs/%s", base));
1485         int retval = 0;
1486
1487         if (dir) {
1488                 struct dirent *de;
1489                 int baselen = strlen(base);
1490                 char *log = xmalloc(baselen + 257);
1491
1492                 memcpy(log, base, baselen);
1493                 if (baselen && base[baselen-1] != '/')
1494                         log[baselen++] = '/';
1495
1496                 while ((de = readdir(dir)) != NULL) {
1497                         struct stat st;
1498                         int namelen;
1499
1500                         if (de->d_name[0] == '.')
1501                                 continue;
1502                         namelen = strlen(de->d_name);
1503                         if (namelen > 255)
1504                                 continue;
1505                         if (has_extension(de->d_name, ".lock"))
1506                                 continue;
1507                         memcpy(log + baselen, de->d_name, namelen+1);
1508                         if (stat(git_path("logs/%s", log), &st) < 0)
1509                                 continue;
1510                         if (S_ISDIR(st.st_mode)) {
1511                                 retval = do_for_each_reflog(log, fn, cb_data);
1512                         } else {
1513                                 unsigned char sha1[20];
1514                                 if (!resolve_ref(log, sha1, 0, NULL))
1515                                         retval = error("bad ref for %s", log);
1516                                 else
1517                                         retval = fn(log, sha1, 0, cb_data);
1518                         }
1519                         if (retval)
1520                                 break;
1521                 }
1522                 free(log);
1523                 closedir(dir);
1524         }
1525         else if (*base)
1526                 return errno;
1527         return retval;
1528 }
1529
1530 int for_each_reflog(each_ref_fn fn, void *cb_data)
1531 {
1532         return do_for_each_reflog("", fn, cb_data);
1533 }
1534
1535 int update_ref(const char *action, const char *refname,
1536                 const unsigned char *sha1, const unsigned char *oldval,
1537                 int flags, enum action_on_err onerr)
1538 {
1539         static struct ref_lock *lock;
1540         lock = lock_any_ref_for_update(refname, oldval, flags);
1541         if (!lock) {
1542                 const char *str = "Cannot lock the ref '%s'.";
1543                 switch (onerr) {
1544                 case MSG_ON_ERR: error(str, refname); break;
1545                 case DIE_ON_ERR: die(str, refname); break;
1546                 case QUIET_ON_ERR: break;
1547                 }
1548                 return 1;
1549         }
1550         if (write_ref_sha1(lock, sha1, action) < 0) {
1551                 const char *str = "Cannot update the ref '%s'.";
1552                 switch (onerr) {
1553                 case MSG_ON_ERR: error(str, refname); break;
1554                 case DIE_ON_ERR: die(str, refname); break;
1555                 case QUIET_ON_ERR: break;
1556                 }
1557                 return 1;
1558         }
1559         return 0;
1560 }
1561
1562 struct ref *find_ref_by_name(struct ref *list, const char *name)
1563 {
1564         for ( ; list; list = list->next)
1565                 if (!strcmp(list->name, name))
1566                         return list;
1567         return NULL;
1568 }