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 const char *resolve_ref(const char *ref, unsigned char *sha1, int reading, int *flag)
394 {
395         int depth = MAXDEPTH;
396         ssize_t len;
397         char buffer[256];
398         static char ref_buffer[256];
399
400         if (flag)
401                 *flag = 0;
402
403         for (;;) {
404                 const char *path = git_path("%s", ref);
405                 struct stat st;
406                 char *buf;
407                 int fd;
408
409                 if (--depth < 0)
410                         return NULL;
411
412                 /* Special case: non-existing file.
413                  * Not having the refs/heads/new-branch is OK
414                  * if we are writing into it, so is .git/HEAD
415                  * that points at refs/heads/master still to be
416                  * born.  It is NOT OK if we are resolving for
417                  * reading.
418                  */
419                 if (lstat(path, &st) < 0) {
420                         struct ref_list *list = get_packed_refs();
421                         while (list) {
422                                 if (!strcmp(ref, list->name)) {
423                                         hashcpy(sha1, list->sha1);
424                                         if (flag)
425                                                 *flag |= REF_ISPACKED;
426                                         return ref;
427                                 }
428                                 list = list->next;
429                         }
430                         if (reading || errno != ENOENT)
431                                 return NULL;
432                         hashclr(sha1);
433                         return ref;
434                 }
435
436                 /* Follow "normalized" - ie "refs/.." symlinks by hand */
437                 if (S_ISLNK(st.st_mode)) {
438                         len = readlink(path, buffer, sizeof(buffer)-1);
439                         if (len >= 5 && !memcmp("refs/", buffer, 5)) {
440                                 buffer[len] = 0;
441                                 strcpy(ref_buffer, buffer);
442                                 ref = ref_buffer;
443                                 if (flag)
444                                         *flag |= REF_ISSYMREF;
445                                 continue;
446                         }
447                 }
448
449                 /* Is it a directory? */
450                 if (S_ISDIR(st.st_mode)) {
451                         errno = EISDIR;
452                         return NULL;
453                 }
454
455                 /*
456                  * Anything else, just open it and try to use it as
457                  * a ref
458                  */
459                 fd = open(path, O_RDONLY);
460                 if (fd < 0)
461                         return NULL;
462                 len = read_in_full(fd, buffer, sizeof(buffer)-1);
463                 close(fd);
464
465                 /*
466                  * Is it a symbolic ref?
467                  */
468                 if (len < 4 || memcmp("ref:", buffer, 4))
469                         break;
470                 buf = buffer + 4;
471                 len -= 4;
472                 while (len && isspace(*buf))
473                         buf++, len--;
474                 while (len && isspace(buf[len-1]))
475                         len--;
476                 buf[len] = 0;
477                 memcpy(ref_buffer, buf, len + 1);
478                 ref = ref_buffer;
479                 if (flag)
480                         *flag |= REF_ISSYMREF;
481         }
482         if (len < 40 || get_sha1_hex(buffer, sha1))
483                 return NULL;
484         return ref;
485 }
486
487 int read_ref(const char *ref, unsigned char *sha1)
488 {
489         if (resolve_ref(ref, sha1, 1, NULL))
490                 return 0;
491         return -1;
492 }
493
494 static int do_one_ref(const char *base, each_ref_fn fn, int trim,
495                       void *cb_data, struct ref_list *entry)
496 {
497         if (strncmp(base, entry->name, trim))
498                 return 0;
499         if (is_null_sha1(entry->sha1))
500                 return 0;
501         if (!has_sha1_file(entry->sha1)) {
502                 error("%s does not point to a valid object!", entry->name);
503                 return 0;
504         }
505         current_ref = entry;
506         return fn(entry->name + trim, entry->sha1, entry->flag, cb_data);
507 }
508
509 int peel_ref(const char *ref, unsigned char *sha1)
510 {
511         int flag;
512         unsigned char base[20];
513         struct object *o;
514
515         if (current_ref && (current_ref->name == ref
516                 || !strcmp(current_ref->name, ref))) {
517                 if (current_ref->flag & REF_KNOWS_PEELED) {
518                         hashcpy(sha1, current_ref->peeled);
519                         return 0;
520                 }
521                 hashcpy(base, current_ref->sha1);
522                 goto fallback;
523         }
524
525         if (!resolve_ref(ref, base, 1, &flag))
526                 return -1;
527
528         if ((flag & REF_ISPACKED)) {
529                 struct ref_list *list = get_packed_refs();
530
531                 while (list) {
532                         if (!strcmp(list->name, ref)) {
533                                 if (list->flag & REF_KNOWS_PEELED) {
534                                         hashcpy(sha1, list->peeled);
535                                         return 0;
536                                 }
537                                 /* older pack-refs did not leave peeled ones */
538                                 break;
539                         }
540                         list = list->next;
541                 }
542         }
543
544 fallback:
545         o = parse_object(base);
546         if (o && o->type == OBJ_TAG) {
547                 o = deref_tag(o, ref, 0);
548                 if (o) {
549                         hashcpy(sha1, o->sha1);
550                         return 0;
551                 }
552         }
553         return -1;
554 }
555
556 static int do_for_each_ref(const char *base, each_ref_fn fn, int trim,
557                            void *cb_data)
558 {
559         int retval = 0;
560         struct ref_list *packed = get_packed_refs();
561         struct ref_list *loose = get_loose_refs();
562
563         struct ref_list *extra;
564
565         for (extra = extra_refs; extra; extra = extra->next)
566                 retval = do_one_ref(base, fn, trim, cb_data, extra);
567
568         while (packed && loose) {
569                 struct ref_list *entry;
570                 int cmp = strcmp(packed->name, loose->name);
571                 if (!cmp) {
572                         packed = packed->next;
573                         continue;
574                 }
575                 if (cmp > 0) {
576                         entry = loose;
577                         loose = loose->next;
578                 } else {
579                         entry = packed;
580                         packed = packed->next;
581                 }
582                 retval = do_one_ref(base, fn, trim, cb_data, entry);
583                 if (retval)
584                         goto end_each;
585         }
586
587         for (packed = packed ? packed : loose; packed; packed = packed->next) {
588                 retval = do_one_ref(base, fn, trim, cb_data, packed);
589                 if (retval)
590                         goto end_each;
591         }
592
593 end_each:
594         current_ref = NULL;
595         return retval;
596 }
597
598 int head_ref(each_ref_fn fn, void *cb_data)
599 {
600         unsigned char sha1[20];
601         int flag;
602
603         if (resolve_ref("HEAD", sha1, 1, &flag))
604                 return fn("HEAD", sha1, flag, cb_data);
605         return 0;
606 }
607
608 int for_each_ref(each_ref_fn fn, void *cb_data)
609 {
610         return do_for_each_ref("refs/", fn, 0, cb_data);
611 }
612
613 int for_each_tag_ref(each_ref_fn fn, void *cb_data)
614 {
615         return do_for_each_ref("refs/tags/", fn, 10, cb_data);
616 }
617
618 int for_each_branch_ref(each_ref_fn fn, void *cb_data)
619 {
620         return do_for_each_ref("refs/heads/", fn, 11, cb_data);
621 }
622
623 int for_each_remote_ref(each_ref_fn fn, void *cb_data)
624 {
625         return do_for_each_ref("refs/remotes/", fn, 13, cb_data);
626 }
627
628 /*
629  * Make sure "ref" is something reasonable to have under ".git/refs/";
630  * We do not like it if:
631  *
632  * - any path component of it begins with ".", or
633  * - it has double dots "..", or
634  * - it has ASCII control character, "~", "^", ":" or SP, anywhere, or
635  * - it ends with a "/".
636  */
637
638 static inline int bad_ref_char(int ch)
639 {
640         if (((unsigned) ch) <= ' ' ||
641             ch == '~' || ch == '^' || ch == ':')
642                 return 1;
643         /* 2.13 Pattern Matching Notation */
644         if (ch == '?' || ch == '[') /* Unsupported */
645                 return 1;
646         if (ch == '*') /* Supported at the end */
647                 return 2;
648         return 0;
649 }
650
651 int check_ref_format(const char *ref)
652 {
653         int ch, level, bad_type;
654         const char *cp = ref;
655
656         level = 0;
657         while (1) {
658                 while ((ch = *cp++) == '/')
659                         ; /* tolerate duplicated slashes */
660                 if (!ch)
661                         /* should not end with slashes */
662                         return CHECK_REF_FORMAT_ERROR;
663
664                 /* we are at the beginning of the path component */
665                 if (ch == '.')
666                         return CHECK_REF_FORMAT_ERROR;
667                 bad_type = bad_ref_char(ch);
668                 if (bad_type) {
669                         return (bad_type == 2 && !*cp)
670                                 ? CHECK_REF_FORMAT_WILDCARD
671                                 : CHECK_REF_FORMAT_ERROR;
672                 }
673
674                 /* scan the rest of the path component */
675                 while ((ch = *cp++) != 0) {
676                         bad_type = bad_ref_char(ch);
677                         if (bad_type) {
678                                 return (bad_type == 2 && !*cp)
679                                         ? CHECK_REF_FORMAT_WILDCARD
680                                         : CHECK_REF_FORMAT_ERROR;
681                         }
682                         if (ch == '/')
683                                 break;
684                         if (ch == '.' && *cp == '.')
685                                 return CHECK_REF_FORMAT_ERROR;
686                 }
687                 level++;
688                 if (!ch) {
689                         if (level < 2)
690                                 return CHECK_REF_FORMAT_ONELEVEL;
691                         return CHECK_REF_FORMAT_OK;
692                 }
693         }
694 }
695
696 const char *ref_rev_parse_rules[] = {
697         "%.*s",
698         "refs/%.*s",
699         "refs/tags/%.*s",
700         "refs/heads/%.*s",
701         "refs/remotes/%.*s",
702         "refs/remotes/%.*s/HEAD",
703         NULL
704 };
705
706 const char *ref_fetch_rules[] = {
707         "%.*s",
708         "refs/%.*s",
709         "refs/heads/%.*s",
710         NULL
711 };
712
713 int refname_match(const char *abbrev_name, const char *full_name, const char **rules)
714 {
715         const char **p;
716         const int abbrev_name_len = strlen(abbrev_name);
717
718         for (p = rules; *p; p++) {
719                 if (!strcmp(full_name, mkpath(*p, abbrev_name_len, abbrev_name))) {
720                         return 1;
721                 }
722         }
723
724         return 0;
725 }
726
727 static struct ref_lock *verify_lock(struct ref_lock *lock,
728         const unsigned char *old_sha1, int mustexist)
729 {
730         if (!resolve_ref(lock->ref_name, lock->old_sha1, mustexist, NULL)) {
731                 error("Can't verify ref %s", lock->ref_name);
732                 unlock_ref(lock);
733                 return NULL;
734         }
735         if (hashcmp(lock->old_sha1, old_sha1)) {
736                 error("Ref %s is at %s but expected %s", lock->ref_name,
737                         sha1_to_hex(lock->old_sha1), sha1_to_hex(old_sha1));
738                 unlock_ref(lock);
739                 return NULL;
740         }
741         return lock;
742 }
743
744 static int remove_empty_directories(const char *file)
745 {
746         /* we want to create a file but there is a directory there;
747          * if that is an empty directory (or a directory that contains
748          * only empty directories), remove them.
749          */
750         struct strbuf path;
751         int result;
752
753         strbuf_init(&path, 20);
754         strbuf_addstr(&path, file);
755
756         result = remove_dir_recursively(&path, 1);
757
758         strbuf_release(&path);
759
760         return result;
761 }
762
763 static int is_refname_available(const char *ref, const char *oldref,
764                                 struct ref_list *list, int quiet)
765 {
766         int namlen = strlen(ref); /* e.g. 'foo/bar' */
767         while (list) {
768                 /* list->name could be 'foo' or 'foo/bar/baz' */
769                 if (!oldref || strcmp(oldref, list->name)) {
770                         int len = strlen(list->name);
771                         int cmplen = (namlen < len) ? namlen : len;
772                         const char *lead = (namlen < len) ? list->name : ref;
773                         if (!strncmp(ref, list->name, cmplen) &&
774                             lead[cmplen] == '/') {
775                                 if (!quiet)
776                                         error("'%s' exists; cannot create '%s'",
777                                               list->name, ref);
778                                 return 0;
779                         }
780                 }
781                 list = list->next;
782         }
783         return 1;
784 }
785
786 static struct ref_lock *lock_ref_sha1_basic(const char *ref, const unsigned char *old_sha1, int flags, int *type_p)
787 {
788         char *ref_file;
789         const char *orig_ref = ref;
790         struct ref_lock *lock;
791         struct stat st;
792         int last_errno = 0;
793         int type;
794         int mustexist = (old_sha1 && !is_null_sha1(old_sha1));
795
796         lock = xcalloc(1, sizeof(struct ref_lock));
797         lock->lock_fd = -1;
798
799         ref = resolve_ref(ref, lock->old_sha1, mustexist, &type);
800         if (!ref && errno == EISDIR) {
801                 /* we are trying to lock foo but we used to
802                  * have foo/bar which now does not exist;
803                  * it is normal for the empty directory 'foo'
804                  * to remain.
805                  */
806                 ref_file = git_path("%s", orig_ref);
807                 if (remove_empty_directories(ref_file)) {
808                         last_errno = errno;
809                         error("there are still refs under '%s'", orig_ref);
810                         goto error_return;
811                 }
812                 ref = resolve_ref(orig_ref, lock->old_sha1, mustexist, &type);
813         }
814         if (type_p)
815             *type_p = type;
816         if (!ref) {
817                 last_errno = errno;
818                 error("unable to resolve reference %s: %s",
819                         orig_ref, strerror(errno));
820                 goto error_return;
821         }
822         /* When the ref did not exist and we are creating it,
823          * make sure there is no existing ref that is packed
824          * whose name begins with our refname, nor a ref whose
825          * name is a proper prefix of our refname.
826          */
827         if (is_null_sha1(lock->old_sha1) &&
828             !is_refname_available(ref, NULL, get_packed_refs(), 0))
829                 goto error_return;
830
831         lock->lk = xcalloc(1, sizeof(struct lock_file));
832
833         if (flags & REF_NODEREF)
834                 ref = orig_ref;
835         lock->ref_name = xstrdup(ref);
836         lock->orig_ref_name = xstrdup(orig_ref);
837         ref_file = git_path("%s", ref);
838         if (lstat(ref_file, &st) && errno == ENOENT)
839                 lock->force_write = 1;
840         if ((flags & REF_NODEREF) && (type & REF_ISSYMREF))
841                 lock->force_write = 1;
842
843         if (safe_create_leading_directories(ref_file)) {
844                 last_errno = errno;
845                 error("unable to create directory for %s", ref_file);
846                 goto error_return;
847         }
848         lock->lock_fd = hold_lock_file_for_update(lock->lk, ref_file, 1);
849
850         return old_sha1 ? verify_lock(lock, old_sha1, mustexist) : lock;
851
852  error_return:
853         unlock_ref(lock);
854         errno = last_errno;
855         return NULL;
856 }
857
858 struct ref_lock *lock_ref_sha1(const char *ref, const unsigned char *old_sha1)
859 {
860         char refpath[PATH_MAX];
861         if (check_ref_format(ref))
862                 return NULL;
863         strcpy(refpath, mkpath("refs/%s", ref));
864         return lock_ref_sha1_basic(refpath, old_sha1, 0, NULL);
865 }
866
867 struct ref_lock *lock_any_ref_for_update(const char *ref, const unsigned char *old_sha1, int flags)
868 {
869         switch (check_ref_format(ref)) {
870         default:
871                 return NULL;
872         case 0:
873         case CHECK_REF_FORMAT_ONELEVEL:
874                 return lock_ref_sha1_basic(ref, old_sha1, flags, NULL);
875         }
876 }
877
878 static struct lock_file packlock;
879
880 static int repack_without_ref(const char *refname)
881 {
882         struct ref_list *list, *packed_ref_list;
883         int fd;
884         int found = 0;
885
886         packed_ref_list = get_packed_refs();
887         for (list = packed_ref_list; list; list = list->next) {
888                 if (!strcmp(refname, list->name)) {
889                         found = 1;
890                         break;
891                 }
892         }
893         if (!found)
894                 return 0;
895         fd = hold_lock_file_for_update(&packlock, git_path("packed-refs"), 0);
896         if (fd < 0)
897                 return error("cannot delete '%s' from packed refs", refname);
898
899         for (list = packed_ref_list; list; list = list->next) {
900                 char line[PATH_MAX + 100];
901                 int len;
902
903                 if (!strcmp(refname, list->name))
904                         continue;
905                 len = snprintf(line, sizeof(line), "%s %s\n",
906                                sha1_to_hex(list->sha1), list->name);
907                 /* this should not happen but just being defensive */
908                 if (len > sizeof(line))
909                         die("too long a refname '%s'", list->name);
910                 write_or_die(fd, line, len);
911         }
912         return commit_lock_file(&packlock);
913 }
914
915 int delete_ref(const char *refname, const unsigned char *sha1)
916 {
917         struct ref_lock *lock;
918         int err, i, ret = 0, flag = 0;
919
920         lock = lock_ref_sha1_basic(refname, sha1, 0, &flag);
921         if (!lock)
922                 return 1;
923         if (!(flag & REF_ISPACKED)) {
924                 /* loose */
925                 i = strlen(lock->lk->filename) - 5; /* .lock */
926                 lock->lk->filename[i] = 0;
927                 err = unlink(lock->lk->filename);
928                 if (err && errno != ENOENT) {
929                         ret = 1;
930                         error("unlink(%s) failed: %s",
931                               lock->lk->filename, strerror(errno));
932                 }
933                 lock->lk->filename[i] = '.';
934         }
935         /* removing the loose one could have resurrected an earlier
936          * packed one.  Also, if it was not loose we need to repack
937          * without it.
938          */
939         ret |= repack_without_ref(refname);
940
941         err = unlink(git_path("logs/%s", lock->ref_name));
942         if (err && errno != ENOENT)
943                 fprintf(stderr, "warning: unlink(%s) failed: %s",
944                         git_path("logs/%s", lock->ref_name), strerror(errno));
945         invalidate_cached_refs();
946         unlock_ref(lock);
947         return ret;
948 }
949
950 int rename_ref(const char *oldref, const char *newref, const char *logmsg)
951 {
952         static const char renamed_ref[] = "RENAMED-REF";
953         unsigned char sha1[20], orig_sha1[20];
954         int flag = 0, logmoved = 0;
955         struct ref_lock *lock;
956         struct stat loginfo;
957         int log = !lstat(git_path("logs/%s", oldref), &loginfo);
958
959         if (S_ISLNK(loginfo.st_mode))
960                 return error("reflog for %s is a symlink", oldref);
961
962         if (!resolve_ref(oldref, orig_sha1, 1, &flag))
963                 return error("refname %s not found", oldref);
964
965         if (!is_refname_available(newref, oldref, get_packed_refs(), 0))
966                 return 1;
967
968         if (!is_refname_available(newref, oldref, get_loose_refs(), 0))
969                 return 1;
970
971         lock = lock_ref_sha1_basic(renamed_ref, NULL, 0, NULL);
972         if (!lock)
973                 return error("unable to lock %s", renamed_ref);
974         lock->force_write = 1;
975         if (write_ref_sha1(lock, orig_sha1, logmsg))
976                 return error("unable to save current sha1 in %s", renamed_ref);
977
978         if (log && rename(git_path("logs/%s", oldref), git_path("tmp-renamed-log")))
979                 return error("unable to move logfile logs/%s to tmp-renamed-log: %s",
980                         oldref, strerror(errno));
981
982         if (delete_ref(oldref, orig_sha1)) {
983                 error("unable to delete old %s", oldref);
984                 goto rollback;
985         }
986
987         if (resolve_ref(newref, sha1, 1, &flag) && delete_ref(newref, sha1)) {
988                 if (errno==EISDIR) {
989                         if (remove_empty_directories(git_path("%s", newref))) {
990                                 error("Directory not empty: %s", newref);
991                                 goto rollback;
992                         }
993                 } else {
994                         error("unable to delete existing %s", newref);
995                         goto rollback;
996                 }
997         }
998
999         if (log && safe_create_leading_directories(git_path("logs/%s", newref))) {
1000                 error("unable to create directory for %s", newref);
1001                 goto rollback;
1002         }
1003
1004  retry:
1005         if (log && rename(git_path("tmp-renamed-log"), git_path("logs/%s", newref))) {
1006                 if (errno==EISDIR || errno==ENOTDIR) {
1007                         /*
1008                          * rename(a, b) when b is an existing
1009                          * directory ought to result in ISDIR, but
1010                          * Solaris 5.8 gives ENOTDIR.  Sheesh.
1011                          */
1012                         if (remove_empty_directories(git_path("logs/%s", newref))) {
1013                                 error("Directory not empty: logs/%s", newref);
1014                                 goto rollback;
1015                         }
1016                         goto retry;
1017                 } else {
1018                         error("unable to move logfile tmp-renamed-log to logs/%s: %s",
1019                                 newref, strerror(errno));
1020                         goto rollback;
1021                 }
1022         }
1023         logmoved = log;
1024
1025         lock = lock_ref_sha1_basic(newref, NULL, 0, NULL);
1026         if (!lock) {
1027                 error("unable to lock %s for update", newref);
1028                 goto rollback;
1029         }
1030
1031         lock->force_write = 1;
1032         hashcpy(lock->old_sha1, orig_sha1);
1033         if (write_ref_sha1(lock, orig_sha1, logmsg)) {
1034                 error("unable to write current sha1 into %s", newref);
1035                 goto rollback;
1036         }
1037
1038         return 0;
1039
1040  rollback:
1041         lock = lock_ref_sha1_basic(oldref, NULL, 0, NULL);
1042         if (!lock) {
1043                 error("unable to lock %s for rollback", oldref);
1044                 goto rollbacklog;
1045         }
1046
1047         lock->force_write = 1;
1048         flag = log_all_ref_updates;
1049         log_all_ref_updates = 0;
1050         if (write_ref_sha1(lock, orig_sha1, NULL))
1051                 error("unable to write current sha1 into %s", oldref);
1052         log_all_ref_updates = flag;
1053
1054  rollbacklog:
1055         if (logmoved && rename(git_path("logs/%s", newref), git_path("logs/%s", oldref)))
1056                 error("unable to restore logfile %s from %s: %s",
1057                         oldref, newref, strerror(errno));
1058         if (!logmoved && log &&
1059             rename(git_path("tmp-renamed-log"), git_path("logs/%s", oldref)))
1060                 error("unable to restore logfile %s from tmp-renamed-log: %s",
1061                         oldref, strerror(errno));
1062
1063         return 1;
1064 }
1065
1066 int close_ref(struct ref_lock *lock)
1067 {
1068         if (close_lock_file(lock->lk))
1069                 return -1;
1070         lock->lock_fd = -1;
1071         return 0;
1072 }
1073
1074 int commit_ref(struct ref_lock *lock)
1075 {
1076         if (commit_lock_file(lock->lk))
1077                 return -1;
1078         lock->lock_fd = -1;
1079         return 0;
1080 }
1081
1082 void unlock_ref(struct ref_lock *lock)
1083 {
1084         /* Do not free lock->lk -- atexit() still looks at them */
1085         if (lock->lk)
1086                 rollback_lock_file(lock->lk);
1087         free(lock->ref_name);
1088         free(lock->orig_ref_name);
1089         free(lock);
1090 }
1091
1092 /*
1093  * copy the reflog message msg to buf, which has been allocated sufficiently
1094  * large, while cleaning up the whitespaces.  Especially, convert LF to space,
1095  * because reflog file is one line per entry.
1096  */
1097 static int copy_msg(char *buf, const char *msg)
1098 {
1099         char *cp = buf;
1100         char c;
1101         int wasspace = 1;
1102
1103         *cp++ = '\t';
1104         while ((c = *msg++)) {
1105                 if (wasspace && isspace(c))
1106                         continue;
1107                 wasspace = isspace(c);
1108                 if (wasspace)
1109                         c = ' ';
1110                 *cp++ = c;
1111         }
1112         while (buf < cp && isspace(cp[-1]))
1113                 cp--;
1114         *cp++ = '\n';
1115         return cp - buf;
1116 }
1117
1118 static int log_ref_write(const char *ref_name, const unsigned char *old_sha1,
1119                          const unsigned char *new_sha1, const char *msg)
1120 {
1121         int logfd, written, oflags = O_APPEND | O_WRONLY;
1122         unsigned maxlen, len;
1123         int msglen;
1124         char *log_file, *logrec;
1125         const char *committer;
1126
1127         if (log_all_ref_updates < 0)
1128                 log_all_ref_updates = !is_bare_repository();
1129
1130         log_file = git_path("logs/%s", ref_name);
1131
1132         if (log_all_ref_updates &&
1133             (!prefixcmp(ref_name, "refs/heads/") ||
1134              !prefixcmp(ref_name, "refs/remotes/") ||
1135              !strcmp(ref_name, "HEAD"))) {
1136                 if (safe_create_leading_directories(log_file) < 0)
1137                         return error("unable to create directory for %s",
1138                                      log_file);
1139                 oflags |= O_CREAT;
1140         }
1141
1142         logfd = open(log_file, oflags, 0666);
1143         if (logfd < 0) {
1144                 if (!(oflags & O_CREAT) && errno == ENOENT)
1145                         return 0;
1146
1147                 if ((oflags & O_CREAT) && errno == EISDIR) {
1148                         if (remove_empty_directories(log_file)) {
1149                                 return error("There are still logs under '%s'",
1150                                              log_file);
1151                         }
1152                         logfd = open(log_file, oflags, 0666);
1153                 }
1154
1155                 if (logfd < 0)
1156                         return error("Unable to append to %s: %s",
1157                                      log_file, strerror(errno));
1158         }
1159
1160         adjust_shared_perm(log_file);
1161
1162         msglen = msg ? strlen(msg) : 0;
1163         committer = git_committer_info(0);
1164         maxlen = strlen(committer) + msglen + 100;
1165         logrec = xmalloc(maxlen);
1166         len = sprintf(logrec, "%s %s %s\n",
1167                       sha1_to_hex(old_sha1),
1168                       sha1_to_hex(new_sha1),
1169                       committer);
1170         if (msglen)
1171                 len += copy_msg(logrec + len - 1, msg) - 1;
1172         written = len <= maxlen ? write_in_full(logfd, logrec, len) : -1;
1173         free(logrec);
1174         if (close(logfd) != 0 || written != len)
1175                 return error("Unable to append to %s", log_file);
1176         return 0;
1177 }
1178
1179 static int is_branch(const char *refname)
1180 {
1181         return !strcmp(refname, "HEAD") || !prefixcmp(refname, "refs/heads/");
1182 }
1183
1184 int write_ref_sha1(struct ref_lock *lock,
1185         const unsigned char *sha1, const char *logmsg)
1186 {
1187         static char term = '\n';
1188         struct object *o;
1189
1190         if (!lock)
1191                 return -1;
1192         if (!lock->force_write && !hashcmp(lock->old_sha1, sha1)) {
1193                 unlock_ref(lock);
1194                 return 0;
1195         }
1196         o = parse_object(sha1);
1197         if (!o) {
1198                 error("Trying to write ref %s with nonexistant object %s",
1199                         lock->ref_name, sha1_to_hex(sha1));
1200                 unlock_ref(lock);
1201                 return -1;
1202         }
1203         if (o->type != OBJ_COMMIT && is_branch(lock->ref_name)) {
1204                 error("Trying to write non-commit object %s to branch %s",
1205                         sha1_to_hex(sha1), lock->ref_name);
1206                 unlock_ref(lock);
1207                 return -1;
1208         }
1209         if (write_in_full(lock->lock_fd, sha1_to_hex(sha1), 40) != 40 ||
1210             write_in_full(lock->lock_fd, &term, 1) != 1
1211                 || close_ref(lock) < 0) {
1212                 error("Couldn't write %s", lock->lk->filename);
1213                 unlock_ref(lock);
1214                 return -1;
1215         }
1216         invalidate_cached_refs();
1217         if (log_ref_write(lock->ref_name, lock->old_sha1, sha1, logmsg) < 0 ||
1218             (strcmp(lock->ref_name, lock->orig_ref_name) &&
1219              log_ref_write(lock->orig_ref_name, lock->old_sha1, sha1, logmsg) < 0)) {
1220                 unlock_ref(lock);
1221                 return -1;
1222         }
1223         if (strcmp(lock->orig_ref_name, "HEAD") != 0) {
1224                 /*
1225                  * Special hack: If a branch is updated directly and HEAD
1226                  * points to it (may happen on the remote side of a push
1227                  * for example) then logically the HEAD reflog should be
1228                  * updated too.
1229                  * A generic solution implies reverse symref information,
1230                  * but finding all symrefs pointing to the given branch
1231                  * would be rather costly for this rare event (the direct
1232                  * update of a branch) to be worth it.  So let's cheat and
1233                  * check with HEAD only which should cover 99% of all usage
1234                  * scenarios (even 100% of the default ones).
1235                  */
1236                 unsigned char head_sha1[20];
1237                 int head_flag;
1238                 const char *head_ref;
1239                 head_ref = resolve_ref("HEAD", head_sha1, 1, &head_flag);
1240                 if (head_ref && (head_flag & REF_ISSYMREF) &&
1241                     !strcmp(head_ref, lock->ref_name))
1242                         log_ref_write("HEAD", lock->old_sha1, sha1, logmsg);
1243         }
1244         if (commit_ref(lock)) {
1245                 error("Couldn't set %s", lock->ref_name);
1246                 unlock_ref(lock);
1247                 return -1;
1248         }
1249         unlock_ref(lock);
1250         return 0;
1251 }
1252
1253 int create_symref(const char *ref_target, const char *refs_heads_master,
1254                   const char *logmsg)
1255 {
1256         const char *lockpath;
1257         char ref[1000];
1258         int fd, len, written;
1259         char *git_HEAD = xstrdup(git_path("%s", ref_target));
1260         unsigned char old_sha1[20], new_sha1[20];
1261
1262         if (logmsg && read_ref(ref_target, old_sha1))
1263                 hashclr(old_sha1);
1264
1265         if (safe_create_leading_directories(git_HEAD) < 0)
1266                 return error("unable to create directory for %s", git_HEAD);
1267
1268 #ifndef NO_SYMLINK_HEAD
1269         if (prefer_symlink_refs) {
1270                 unlink(git_HEAD);
1271                 if (!symlink(refs_heads_master, git_HEAD))
1272                         goto done;
1273                 fprintf(stderr, "no symlink - falling back to symbolic ref\n");
1274         }
1275 #endif
1276
1277         len = snprintf(ref, sizeof(ref), "ref: %s\n", refs_heads_master);
1278         if (sizeof(ref) <= len) {
1279                 error("refname too long: %s", refs_heads_master);
1280                 goto error_free_return;
1281         }
1282         lockpath = mkpath("%s.lock", git_HEAD);
1283         fd = open(lockpath, O_CREAT | O_EXCL | O_WRONLY, 0666);
1284         if (fd < 0) {
1285                 error("Unable to open %s for writing", lockpath);
1286                 goto error_free_return;
1287         }
1288         written = write_in_full(fd, ref, len);
1289         if (close(fd) != 0 || written != len) {
1290                 error("Unable to write to %s", lockpath);
1291                 goto error_unlink_return;
1292         }
1293         if (rename(lockpath, git_HEAD) < 0) {
1294                 error("Unable to create %s", git_HEAD);
1295                 goto error_unlink_return;
1296         }
1297         if (adjust_shared_perm(git_HEAD)) {
1298                 error("Unable to fix permissions on %s", lockpath);
1299         error_unlink_return:
1300                 unlink(lockpath);
1301         error_free_return:
1302                 free(git_HEAD);
1303                 return -1;
1304         }
1305
1306 #ifndef NO_SYMLINK_HEAD
1307         done:
1308 #endif
1309         if (logmsg && !read_ref(refs_heads_master, new_sha1))
1310                 log_ref_write(ref_target, old_sha1, new_sha1, logmsg);
1311
1312         free(git_HEAD);
1313         return 0;
1314 }
1315
1316 static char *ref_msg(const char *line, const char *endp)
1317 {
1318         const char *ep;
1319         line += 82;
1320         ep = memchr(line, '\n', endp - line);
1321         if (!ep)
1322                 ep = endp;
1323         return xmemdupz(line, ep - line);
1324 }
1325
1326 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)
1327 {
1328         const char *logfile, *logdata, *logend, *rec, *lastgt, *lastrec;
1329         char *tz_c;
1330         int logfd, tz, reccnt = 0;
1331         struct stat st;
1332         unsigned long date;
1333         unsigned char logged_sha1[20];
1334         void *log_mapped;
1335         size_t mapsz;
1336
1337         logfile = git_path("logs/%s", ref);
1338         logfd = open(logfile, O_RDONLY, 0);
1339         if (logfd < 0)
1340                 die("Unable to read log %s: %s", logfile, strerror(errno));
1341         fstat(logfd, &st);
1342         if (!st.st_size)
1343                 die("Log %s is empty.", logfile);
1344         mapsz = xsize_t(st.st_size);
1345         log_mapped = xmmap(NULL, mapsz, PROT_READ, MAP_PRIVATE, logfd, 0);
1346         logdata = log_mapped;
1347         close(logfd);
1348
1349         lastrec = NULL;
1350         rec = logend = logdata + st.st_size;
1351         while (logdata < rec) {
1352                 reccnt++;
1353                 if (logdata < rec && *(rec-1) == '\n')
1354                         rec--;
1355                 lastgt = NULL;
1356                 while (logdata < rec && *(rec-1) != '\n') {
1357                         rec--;
1358                         if (*rec == '>')
1359                                 lastgt = rec;
1360                 }
1361                 if (!lastgt)
1362                         die("Log %s is corrupt.", logfile);
1363                 date = strtoul(lastgt + 1, &tz_c, 10);
1364                 if (date <= at_time || cnt == 0) {
1365                         tz = strtoul(tz_c, NULL, 10);
1366                         if (msg)
1367                                 *msg = ref_msg(rec, logend);
1368                         if (cutoff_time)
1369                                 *cutoff_time = date;
1370                         if (cutoff_tz)
1371                                 *cutoff_tz = tz;
1372                         if (cutoff_cnt)
1373                                 *cutoff_cnt = reccnt - 1;
1374                         if (lastrec) {
1375                                 if (get_sha1_hex(lastrec, logged_sha1))
1376                                         die("Log %s is corrupt.", logfile);
1377                                 if (get_sha1_hex(rec + 41, sha1))
1378                                         die("Log %s is corrupt.", logfile);
1379                                 if (hashcmp(logged_sha1, sha1)) {
1380                                         fprintf(stderr,
1381                                                 "warning: Log %s has gap after %s.\n",
1382                                                 logfile, show_date(date, tz, DATE_RFC2822));
1383                                 }
1384                         }
1385                         else if (date == at_time) {
1386                                 if (get_sha1_hex(rec + 41, sha1))
1387                                         die("Log %s is corrupt.", logfile);
1388                         }
1389                         else {
1390                                 if (get_sha1_hex(rec + 41, logged_sha1))
1391                                         die("Log %s is corrupt.", logfile);
1392                                 if (hashcmp(logged_sha1, sha1)) {
1393                                         fprintf(stderr,
1394                                                 "warning: Log %s unexpectedly ended on %s.\n",
1395                                                 logfile, show_date(date, tz, DATE_RFC2822));
1396                                 }
1397                         }
1398                         munmap(log_mapped, mapsz);
1399                         return 0;
1400                 }
1401                 lastrec = rec;
1402                 if (cnt > 0)
1403                         cnt--;
1404         }
1405
1406         rec = logdata;
1407         while (rec < logend && *rec != '>' && *rec != '\n')
1408                 rec++;
1409         if (rec == logend || *rec == '\n')
1410                 die("Log %s is corrupt.", logfile);
1411         date = strtoul(rec + 1, &tz_c, 10);
1412         tz = strtoul(tz_c, NULL, 10);
1413         if (get_sha1_hex(logdata, sha1))
1414                 die("Log %s is corrupt.", logfile);
1415         if (is_null_sha1(sha1)) {
1416                 if (get_sha1_hex(logdata + 41, sha1))
1417                         die("Log %s is corrupt.", logfile);
1418         }
1419         if (msg)
1420                 *msg = ref_msg(logdata, logend);
1421         munmap(log_mapped, mapsz);
1422
1423         if (cutoff_time)
1424                 *cutoff_time = date;
1425         if (cutoff_tz)
1426                 *cutoff_tz = tz;
1427         if (cutoff_cnt)
1428                 *cutoff_cnt = reccnt;
1429         return 1;
1430 }
1431
1432 int for_each_reflog_ent(const char *ref, each_reflog_ent_fn fn, void *cb_data)
1433 {
1434         const char *logfile;
1435         FILE *logfp;
1436         char buf[1024];
1437         int ret = 0;
1438
1439         logfile = git_path("logs/%s", ref);
1440         logfp = fopen(logfile, "r");
1441         if (!logfp)
1442                 return -1;
1443         while (fgets(buf, sizeof(buf), logfp)) {
1444                 unsigned char osha1[20], nsha1[20];
1445                 char *email_end, *message;
1446                 unsigned long timestamp;
1447                 int len, tz;
1448
1449                 /* old SP new SP name <email> SP time TAB msg LF */
1450                 len = strlen(buf);
1451                 if (len < 83 || buf[len-1] != '\n' ||
1452                     get_sha1_hex(buf, osha1) || buf[40] != ' ' ||
1453                     get_sha1_hex(buf + 41, nsha1) || buf[81] != ' ' ||
1454                     !(email_end = strchr(buf + 82, '>')) ||
1455                     email_end[1] != ' ' ||
1456                     !(timestamp = strtoul(email_end + 2, &message, 10)) ||
1457                     !message || message[0] != ' ' ||
1458                     (message[1] != '+' && message[1] != '-') ||
1459                     !isdigit(message[2]) || !isdigit(message[3]) ||
1460                     !isdigit(message[4]) || !isdigit(message[5]))
1461                         continue; /* corrupt? */
1462                 email_end[1] = '\0';
1463                 tz = strtol(message + 1, NULL, 10);
1464                 if (message[6] != '\t')
1465                         message += 6;
1466                 else
1467                         message += 7;
1468                 ret = fn(osha1, nsha1, buf+82, timestamp, tz, message, cb_data);
1469                 if (ret)
1470                         break;
1471         }
1472         fclose(logfp);
1473         return ret;
1474 }
1475
1476 static int do_for_each_reflog(const char *base, each_ref_fn fn, void *cb_data)
1477 {
1478         DIR *dir = opendir(git_path("logs/%s", base));
1479         int retval = 0;
1480
1481         if (dir) {
1482                 struct dirent *de;
1483                 int baselen = strlen(base);
1484                 char *log = xmalloc(baselen + 257);
1485
1486                 memcpy(log, base, baselen);
1487                 if (baselen && base[baselen-1] != '/')
1488                         log[baselen++] = '/';
1489
1490                 while ((de = readdir(dir)) != NULL) {
1491                         struct stat st;
1492                         int namelen;
1493
1494                         if (de->d_name[0] == '.')
1495                                 continue;
1496                         namelen = strlen(de->d_name);
1497                         if (namelen > 255)
1498                                 continue;
1499                         if (has_extension(de->d_name, ".lock"))
1500                                 continue;
1501                         memcpy(log + baselen, de->d_name, namelen+1);
1502                         if (stat(git_path("logs/%s", log), &st) < 0)
1503                                 continue;
1504                         if (S_ISDIR(st.st_mode)) {
1505                                 retval = do_for_each_reflog(log, fn, cb_data);
1506                         } else {
1507                                 unsigned char sha1[20];
1508                                 if (!resolve_ref(log, sha1, 0, NULL))
1509                                         retval = error("bad ref for %s", log);
1510                                 else
1511                                         retval = fn(log, sha1, 0, cb_data);
1512                         }
1513                         if (retval)
1514                                 break;
1515                 }
1516                 free(log);
1517                 closedir(dir);
1518         }
1519         else if (*base)
1520                 return errno;
1521         return retval;
1522 }
1523
1524 int for_each_reflog(each_ref_fn fn, void *cb_data)
1525 {
1526         return do_for_each_reflog("", fn, cb_data);
1527 }
1528
1529 int update_ref(const char *action, const char *refname,
1530                 const unsigned char *sha1, const unsigned char *oldval,
1531                 int flags, enum action_on_err onerr)
1532 {
1533         static struct ref_lock *lock;
1534         lock = lock_any_ref_for_update(refname, oldval, flags);
1535         if (!lock) {
1536                 const char *str = "Cannot lock the ref '%s'.";
1537                 switch (onerr) {
1538                 case MSG_ON_ERR: error(str, refname); break;
1539                 case DIE_ON_ERR: die(str, refname); break;
1540                 case QUIET_ON_ERR: break;
1541                 }
1542                 return 1;
1543         }
1544         if (write_ref_sha1(lock, sha1, action) < 0) {
1545                 const char *str = "Cannot update the ref '%s'.";
1546                 switch (onerr) {
1547                 case MSG_ON_ERR: error(str, refname); break;
1548                 case DIE_ON_ERR: die(str, refname); break;
1549                 case QUIET_ON_ERR: break;
1550                 }
1551                 return 1;
1552         }
1553         return 0;
1554 }
1555
1556 struct ref *find_ref_by_name(struct ref *list, const char *name)
1557 {
1558         for ( ; list; list = list->next)
1559                 if (!strcmp(list->name, name))
1560                         return list;
1561         return NULL;
1562 }