Merge branch 'maint'
[git] / refs.c
1 #include "cache.h"
2 #include "refs.h"
3 #include "object.h"
4 #include "tag.h"
5
6 /* ISSYMREF=01 and ISPACKED=02 are public interfaces */
7 #define REF_KNOWS_PEELED 04
8
9 struct ref_list {
10         struct ref_list *next;
11         unsigned char flag; /* ISSYMREF? ISPACKED? */
12         unsigned char sha1[20];
13         unsigned char peeled[20];
14         char name[FLEX_ARRAY];
15 };
16
17 static const char *parse_ref_line(char *line, unsigned char *sha1)
18 {
19         /*
20          * 42: the answer to everything.
21          *
22          * In this case, it happens to be the answer to
23          *  40 (length of sha1 hex representation)
24          *  +1 (space in between hex and name)
25          *  +1 (newline at the end of the line)
26          */
27         int len = strlen(line) - 42;
28
29         if (len <= 0)
30                 return NULL;
31         if (get_sha1_hex(line, sha1) < 0)
32                 return NULL;
33         if (!isspace(line[40]))
34                 return NULL;
35         line += 41;
36         if (isspace(*line))
37                 return NULL;
38         if (line[len] != '\n')
39                 return NULL;
40         line[len] = 0;
41
42         return line;
43 }
44
45 static struct ref_list *add_ref(const char *name, const unsigned char *sha1,
46                                 int flag, struct ref_list *list,
47                                 struct ref_list **new_entry)
48 {
49         int len;
50         struct ref_list **p = &list, *entry;
51
52         /* Find the place to insert the ref into.. */
53         while ((entry = *p) != NULL) {
54                 int cmp = strcmp(entry->name, name);
55                 if (cmp > 0)
56                         break;
57
58                 /* Same as existing entry? */
59                 if (!cmp) {
60                         if (new_entry)
61                                 *new_entry = entry;
62                         return list;
63                 }
64                 p = &entry->next;
65         }
66
67         /* Allocate it and add it in.. */
68         len = strlen(name) + 1;
69         entry = xmalloc(sizeof(struct ref_list) + len);
70         hashcpy(entry->sha1, sha1);
71         hashclr(entry->peeled);
72         memcpy(entry->name, name, len);
73         entry->flag = flag;
74         entry->next = *p;
75         *p = entry;
76         if (new_entry)
77                 *new_entry = entry;
78         return list;
79 }
80
81 /*
82  * Future: need to be in "struct repository"
83  * when doing a full libification.
84  */
85 struct cached_refs {
86         char did_loose;
87         char did_packed;
88         struct ref_list *loose;
89         struct ref_list *packed;
90 } cached_refs;
91
92 static void free_ref_list(struct ref_list *list)
93 {
94         struct ref_list *next;
95         for ( ; list; list = next) {
96                 next = list->next;
97                 free(list);
98         }
99 }
100
101 static void invalidate_cached_refs(void)
102 {
103         struct cached_refs *ca = &cached_refs;
104
105         if (ca->did_loose && ca->loose)
106                 free_ref_list(ca->loose);
107         if (ca->did_packed && ca->packed)
108                 free_ref_list(ca->packed);
109         ca->loose = ca->packed = NULL;
110         ca->did_loose = ca->did_packed = 0;
111 }
112
113 static void read_packed_refs(FILE *f, struct cached_refs *cached_refs)
114 {
115         struct ref_list *list = NULL;
116         struct ref_list *last = NULL;
117         char refline[PATH_MAX];
118         int flag = REF_ISPACKED;
119
120         while (fgets(refline, sizeof(refline), f)) {
121                 unsigned char sha1[20];
122                 const char *name;
123                 static const char header[] = "# pack-refs with:";
124
125                 if (!strncmp(refline, header, sizeof(header)-1)) {
126                         const char *traits = refline + sizeof(header) - 1;
127                         if (strstr(traits, " peeled "))
128                                 flag |= REF_KNOWS_PEELED;
129                         /* perhaps other traits later as well */
130                         continue;
131                 }
132
133                 name = parse_ref_line(refline, sha1);
134                 if (name) {
135                         list = add_ref(name, sha1, flag, list, &last);
136                         continue;
137                 }
138                 if (last &&
139                     refline[0] == '^' &&
140                     strlen(refline) == 42 &&
141                     refline[41] == '\n' &&
142                     !get_sha1_hex(refline + 1, sha1))
143                         hashcpy(last->peeled, sha1);
144         }
145         cached_refs->packed = list;
146 }
147
148 static struct ref_list *get_packed_refs(void)
149 {
150         if (!cached_refs.did_packed) {
151                 FILE *f = fopen(git_path("packed-refs"), "r");
152                 cached_refs.packed = NULL;
153                 if (f) {
154                         read_packed_refs(f, &cached_refs);
155                         fclose(f);
156                 }
157                 cached_refs.did_packed = 1;
158         }
159         return cached_refs.packed;
160 }
161
162 static struct ref_list *get_ref_dir(const char *base, struct ref_list *list)
163 {
164         DIR *dir = opendir(git_path("%s", base));
165
166         if (dir) {
167                 struct dirent *de;
168                 int baselen = strlen(base);
169                 char *ref = xmalloc(baselen + 257);
170
171                 memcpy(ref, base, baselen);
172                 if (baselen && base[baselen-1] != '/')
173                         ref[baselen++] = '/';
174
175                 while ((de = readdir(dir)) != NULL) {
176                         unsigned char sha1[20];
177                         struct stat st;
178                         int flag;
179                         int namelen;
180
181                         if (de->d_name[0] == '.')
182                                 continue;
183                         namelen = strlen(de->d_name);
184                         if (namelen > 255)
185                                 continue;
186                         if (has_extension(de->d_name, ".lock"))
187                                 continue;
188                         memcpy(ref + baselen, de->d_name, namelen+1);
189                         if (stat(git_path("%s", ref), &st) < 0)
190                                 continue;
191                         if (S_ISDIR(st.st_mode)) {
192                                 list = get_ref_dir(ref, list);
193                                 continue;
194                         }
195                         if (!resolve_ref(ref, sha1, 1, &flag)) {
196                                 error("%s points nowhere!", ref);
197                                 continue;
198                         }
199                         list = add_ref(ref, sha1, flag, list, NULL);
200                 }
201                 free(ref);
202                 closedir(dir);
203         }
204         return list;
205 }
206
207 static struct ref_list *get_loose_refs(void)
208 {
209         if (!cached_refs.did_loose) {
210                 cached_refs.loose = get_ref_dir("refs", NULL);
211                 cached_refs.did_loose = 1;
212         }
213         return cached_refs.loose;
214 }
215
216 /* We allow "recursive" symbolic refs. Only within reason, though */
217 #define MAXDEPTH 5
218
219 const char *resolve_ref(const char *ref, unsigned char *sha1, int reading, int *flag)
220 {
221         int depth = MAXDEPTH, len;
222         char buffer[256];
223         static char ref_buffer[256];
224
225         if (flag)
226                 *flag = 0;
227
228         for (;;) {
229                 const char *path = git_path("%s", ref);
230                 struct stat st;
231                 char *buf;
232                 int fd;
233
234                 if (--depth < 0)
235                         return NULL;
236
237                 /* Special case: non-existing file.
238                  * Not having the refs/heads/new-branch is OK
239                  * if we are writing into it, so is .git/HEAD
240                  * that points at refs/heads/master still to be
241                  * born.  It is NOT OK if we are resolving for
242                  * reading.
243                  */
244                 if (lstat(path, &st) < 0) {
245                         struct ref_list *list = get_packed_refs();
246                         while (list) {
247                                 if (!strcmp(ref, list->name)) {
248                                         hashcpy(sha1, list->sha1);
249                                         if (flag)
250                                                 *flag |= REF_ISPACKED;
251                                         return ref;
252                                 }
253                                 list = list->next;
254                         }
255                         if (reading || errno != ENOENT)
256                                 return NULL;
257                         hashclr(sha1);
258                         return ref;
259                 }
260
261                 /* Follow "normalized" - ie "refs/.." symlinks by hand */
262                 if (S_ISLNK(st.st_mode)) {
263                         len = readlink(path, buffer, sizeof(buffer)-1);
264                         if (len >= 5 && !memcmp("refs/", buffer, 5)) {
265                                 buffer[len] = 0;
266                                 strcpy(ref_buffer, buffer);
267                                 ref = ref_buffer;
268                                 if (flag)
269                                         *flag |= REF_ISSYMREF;
270                                 continue;
271                         }
272                 }
273
274                 /* Is it a directory? */
275                 if (S_ISDIR(st.st_mode)) {
276                         errno = EISDIR;
277                         return NULL;
278                 }
279
280                 /*
281                  * Anything else, just open it and try to use it as
282                  * a ref
283                  */
284                 fd = open(path, O_RDONLY);
285                 if (fd < 0)
286                         return NULL;
287                 len = read_in_full(fd, buffer, sizeof(buffer)-1);
288                 close(fd);
289
290                 /*
291                  * Is it a symbolic ref?
292                  */
293                 if (len < 4 || memcmp("ref:", buffer, 4))
294                         break;
295                 buf = buffer + 4;
296                 len -= 4;
297                 while (len && isspace(*buf))
298                         buf++, len--;
299                 while (len && isspace(buf[len-1]))
300                         len--;
301                 buf[len] = 0;
302                 memcpy(ref_buffer, buf, len + 1);
303                 ref = ref_buffer;
304                 if (flag)
305                         *flag |= REF_ISSYMREF;
306         }
307         if (len < 40 || get_sha1_hex(buffer, sha1))
308                 return NULL;
309         return ref;
310 }
311
312 int create_symref(const char *ref_target, const char *refs_heads_master)
313 {
314         const char *lockpath;
315         char ref[1000];
316         int fd, len, written;
317         const char *git_HEAD = git_path("%s", ref_target);
318
319 #ifndef NO_SYMLINK_HEAD
320         if (prefer_symlink_refs) {
321                 unlink(git_HEAD);
322                 if (!symlink(refs_heads_master, git_HEAD))
323                         return 0;
324                 fprintf(stderr, "no symlink - falling back to symbolic ref\n");
325         }
326 #endif
327
328         len = snprintf(ref, sizeof(ref), "ref: %s\n", refs_heads_master);
329         if (sizeof(ref) <= len) {
330                 error("refname too long: %s", refs_heads_master);
331                 return -1;
332         }
333         lockpath = mkpath("%s.lock", git_HEAD);
334         fd = open(lockpath, O_CREAT | O_EXCL | O_WRONLY, 0666); 
335         written = write_in_full(fd, ref, len);
336         close(fd);
337         if (written != len) {
338                 unlink(lockpath);
339                 error("Unable to write to %s", lockpath);
340                 return -2;
341         }
342         if (rename(lockpath, git_HEAD) < 0) {
343                 unlink(lockpath);
344                 error("Unable to create %s", git_HEAD);
345                 return -3;
346         }
347         if (adjust_shared_perm(git_HEAD)) {
348                 unlink(lockpath);
349                 error("Unable to fix permissions on %s", lockpath);
350                 return -4;
351         }
352         return 0;
353 }
354
355 int read_ref(const char *ref, unsigned char *sha1)
356 {
357         if (resolve_ref(ref, sha1, 1, NULL))
358                 return 0;
359         return -1;
360 }
361
362 static int do_one_ref(const char *base, each_ref_fn fn, int trim,
363                       void *cb_data, struct ref_list *entry)
364 {
365         if (strncmp(base, entry->name, trim))
366                 return 0;
367         if (is_null_sha1(entry->sha1))
368                 return 0;
369         if (!has_sha1_file(entry->sha1)) {
370                 error("%s does not point to a valid object!", entry->name);
371                 return 0;
372         }
373         return fn(entry->name + trim, entry->sha1, entry->flag, cb_data);
374 }
375
376 int peel_ref(const char *ref, unsigned char *sha1)
377 {
378         int flag;
379         unsigned char base[20];
380         struct object *o;
381
382         if (!resolve_ref(ref, base, 1, &flag))
383                 return -1;
384
385         if ((flag & REF_ISPACKED)) {
386                 struct ref_list *list = get_packed_refs();
387
388                 while (list) {
389                         if (!strcmp(list->name, ref)) {
390                                 if (list->flag & REF_KNOWS_PEELED) {
391                                         hashcpy(sha1, list->peeled);
392                                         return 0;
393                                 }
394                                 /* older pack-refs did not leave peeled ones */
395                                 break;
396                         }
397                         list = list->next;
398                 }
399         }
400
401         /* fallback - callers should not call this for unpacked refs */
402         o = parse_object(base);
403         if (o->type == OBJ_TAG) {
404                 o = deref_tag(o, ref, 0);
405                 if (o) {
406                         hashcpy(sha1, o->sha1);
407                         return 0;
408                 }
409         }
410         return -1;
411 }
412
413 static int do_for_each_ref(const char *base, each_ref_fn fn, int trim,
414                            void *cb_data)
415 {
416         int retval;
417         struct ref_list *packed = get_packed_refs();
418         struct ref_list *loose = get_loose_refs();
419
420         while (packed && loose) {
421                 struct ref_list *entry;
422                 int cmp = strcmp(packed->name, loose->name);
423                 if (!cmp) {
424                         packed = packed->next;
425                         continue;
426                 }
427                 if (cmp > 0) {
428                         entry = loose;
429                         loose = loose->next;
430                 } else {
431                         entry = packed;
432                         packed = packed->next;
433                 }
434                 retval = do_one_ref(base, fn, trim, cb_data, entry);
435                 if (retval)
436                         return retval;
437         }
438
439         for (packed = packed ? packed : loose; packed; packed = packed->next) {
440                 retval = do_one_ref(base, fn, trim, cb_data, packed);
441                 if (retval)
442                         return retval;
443         }
444         return 0;
445 }
446
447 int head_ref(each_ref_fn fn, void *cb_data)
448 {
449         unsigned char sha1[20];
450         int flag;
451
452         if (resolve_ref("HEAD", sha1, 1, &flag))
453                 return fn("HEAD", sha1, flag, cb_data);
454         return 0;
455 }
456
457 int for_each_ref(each_ref_fn fn, void *cb_data)
458 {
459         return do_for_each_ref("refs/", fn, 0, cb_data);
460 }
461
462 int for_each_tag_ref(each_ref_fn fn, void *cb_data)
463 {
464         return do_for_each_ref("refs/tags/", fn, 10, cb_data);
465 }
466
467 int for_each_branch_ref(each_ref_fn fn, void *cb_data)
468 {
469         return do_for_each_ref("refs/heads/", fn, 11, cb_data);
470 }
471
472 int for_each_remote_ref(each_ref_fn fn, void *cb_data)
473 {
474         return do_for_each_ref("refs/remotes/", fn, 13, cb_data);
475 }
476
477 /* NEEDSWORK: This is only used by ssh-upload and it should go; the
478  * caller should do resolve_ref or read_ref like everybody else.  Or
479  * maybe everybody else should use get_ref_sha1() instead of doing
480  * read_ref().
481  */
482 int get_ref_sha1(const char *ref, unsigned char *sha1)
483 {
484         if (check_ref_format(ref))
485                 return -1;
486         return read_ref(mkpath("refs/%s", ref), sha1);
487 }
488
489 /*
490  * Make sure "ref" is something reasonable to have under ".git/refs/";
491  * We do not like it if:
492  *
493  * - any path component of it begins with ".", or
494  * - it has double dots "..", or
495  * - it has ASCII control character, "~", "^", ":" or SP, anywhere, or
496  * - it ends with a "/".
497  */
498
499 static inline int bad_ref_char(int ch)
500 {
501         return (((unsigned) ch) <= ' ' ||
502                 ch == '~' || ch == '^' || ch == ':' ||
503                 /* 2.13 Pattern Matching Notation */
504                 ch == '?' || ch == '*' || ch == '[');
505 }
506
507 int check_ref_format(const char *ref)
508 {
509         int ch, level;
510         const char *cp = ref;
511
512         level = 0;
513         while (1) {
514                 while ((ch = *cp++) == '/')
515                         ; /* tolerate duplicated slashes */
516                 if (!ch)
517                         return -1; /* should not end with slashes */
518
519                 /* we are at the beginning of the path component */
520                 if (ch == '.' || bad_ref_char(ch))
521                         return -1;
522
523                 /* scan the rest of the path component */
524                 while ((ch = *cp++) != 0) {
525                         if (bad_ref_char(ch))
526                                 return -1;
527                         if (ch == '/')
528                                 break;
529                         if (ch == '.' && *cp == '.')
530                                 return -1;
531                 }
532                 level++;
533                 if (!ch) {
534                         if (level < 2)
535                                 return -2; /* at least of form "heads/blah" */
536                         return 0;
537                 }
538         }
539 }
540
541 static struct ref_lock *verify_lock(struct ref_lock *lock,
542         const unsigned char *old_sha1, int mustexist)
543 {
544         if (!resolve_ref(lock->ref_name, lock->old_sha1, mustexist, NULL)) {
545                 error("Can't verify ref %s", lock->ref_name);
546                 unlock_ref(lock);
547                 return NULL;
548         }
549         if (hashcmp(lock->old_sha1, old_sha1)) {
550                 error("Ref %s is at %s but expected %s", lock->ref_name,
551                         sha1_to_hex(lock->old_sha1), sha1_to_hex(old_sha1));
552                 unlock_ref(lock);
553                 return NULL;
554         }
555         return lock;
556 }
557
558 static int remove_empty_dir_recursive(char *path, int len)
559 {
560         DIR *dir = opendir(path);
561         struct dirent *e;
562         int ret = 0;
563
564         if (!dir)
565                 return -1;
566         if (path[len-1] != '/')
567                 path[len++] = '/';
568         while ((e = readdir(dir)) != NULL) {
569                 struct stat st;
570                 int namlen;
571                 if ((e->d_name[0] == '.') &&
572                     ((e->d_name[1] == 0) ||
573                      ((e->d_name[1] == '.') && e->d_name[2] == 0)))
574                         continue; /* "." and ".." */
575
576                 namlen = strlen(e->d_name);
577                 if ((len + namlen < PATH_MAX) &&
578                     strcpy(path + len, e->d_name) &&
579                     !lstat(path, &st) &&
580                     S_ISDIR(st.st_mode) &&
581                     !remove_empty_dir_recursive(path, len + namlen))
582                         continue; /* happy */
583
584                 /* path too long, stat fails, or non-directory still exists */
585                 ret = -1;
586                 break;
587         }
588         closedir(dir);
589         if (!ret) {
590                 path[len] = 0;
591                 ret = rmdir(path);
592         }
593         return ret;
594 }
595
596 static int remove_empty_directories(char *file)
597 {
598         /* we want to create a file but there is a directory there;
599          * if that is an empty directory (or a directory that contains
600          * only empty directories), remove them.
601          */
602         char path[PATH_MAX];
603         int len = strlen(file);
604
605         if (len >= PATH_MAX) /* path too long ;-) */
606                 return -1;
607         strcpy(path, file);
608         return remove_empty_dir_recursive(path, len);
609 }
610
611 static int is_refname_available(const char *ref, const char *oldref,
612                                 struct ref_list *list, int quiet)
613 {
614         int namlen = strlen(ref); /* e.g. 'foo/bar' */
615         while (list) {
616                 /* list->name could be 'foo' or 'foo/bar/baz' */
617                 if (!oldref || strcmp(oldref, list->name)) {
618                         int len = strlen(list->name);
619                         int cmplen = (namlen < len) ? namlen : len;
620                         const char *lead = (namlen < len) ? list->name : ref;
621                         if (!strncmp(ref, list->name, cmplen) &&
622                             lead[cmplen] == '/') {
623                                 if (!quiet)
624                                         error("'%s' exists; cannot create '%s'",
625                                               list->name, ref);
626                                 return 0;
627                         }
628                 }
629                 list = list->next;
630         }
631         return 1;
632 }
633
634 static struct ref_lock *lock_ref_sha1_basic(const char *ref, const unsigned char *old_sha1, int *flag)
635 {
636         char *ref_file;
637         const char *orig_ref = ref;
638         struct ref_lock *lock;
639         struct stat st;
640         int last_errno = 0;
641         int mustexist = (old_sha1 && !is_null_sha1(old_sha1));
642
643         lock = xcalloc(1, sizeof(struct ref_lock));
644         lock->lock_fd = -1;
645
646         ref = resolve_ref(ref, lock->old_sha1, mustexist, flag);
647         if (!ref && errno == EISDIR) {
648                 /* we are trying to lock foo but we used to
649                  * have foo/bar which now does not exist;
650                  * it is normal for the empty directory 'foo'
651                  * to remain.
652                  */
653                 ref_file = git_path("%s", orig_ref);
654                 if (remove_empty_directories(ref_file)) {
655                         last_errno = errno;
656                         error("there are still refs under '%s'", orig_ref);
657                         goto error_return;
658                 }
659                 ref = resolve_ref(orig_ref, lock->old_sha1, mustexist, flag);
660         }
661         if (!ref) {
662                 last_errno = errno;
663                 error("unable to resolve reference %s: %s",
664                         orig_ref, strerror(errno));
665                 goto error_return;
666         }
667         /* When the ref did not exist and we are creating it,
668          * make sure there is no existing ref that is packed
669          * whose name begins with our refname, nor a ref whose
670          * name is a proper prefix of our refname.
671          */
672         if (is_null_sha1(lock->old_sha1) &&
673             !is_refname_available(ref, NULL, get_packed_refs(), 0))
674                 goto error_return;
675
676         lock->lk = xcalloc(1, sizeof(struct lock_file));
677
678         lock->ref_name = xstrdup(ref);
679         lock->log_file = xstrdup(git_path("logs/%s", ref));
680         ref_file = git_path("%s", ref);
681         lock->force_write = lstat(ref_file, &st) && errno == ENOENT;
682
683         if (safe_create_leading_directories(ref_file)) {
684                 last_errno = errno;
685                 error("unable to create directory for %s", ref_file);
686                 goto error_return;
687         }
688         lock->lock_fd = hold_lock_file_for_update(lock->lk, ref_file, 1);
689
690         return old_sha1 ? verify_lock(lock, old_sha1, mustexist) : lock;
691
692  error_return:
693         unlock_ref(lock);
694         errno = last_errno;
695         return NULL;
696 }
697
698 struct ref_lock *lock_ref_sha1(const char *ref, const unsigned char *old_sha1)
699 {
700         char refpath[PATH_MAX];
701         if (check_ref_format(ref))
702                 return NULL;
703         strcpy(refpath, mkpath("refs/%s", ref));
704         return lock_ref_sha1_basic(refpath, old_sha1, NULL);
705 }
706
707 struct ref_lock *lock_any_ref_for_update(const char *ref, const unsigned char *old_sha1)
708 {
709         return lock_ref_sha1_basic(ref, old_sha1, NULL);
710 }
711
712 static struct lock_file packlock;
713
714 static int repack_without_ref(const char *refname)
715 {
716         struct ref_list *list, *packed_ref_list;
717         int fd;
718         int found = 0;
719
720         packed_ref_list = get_packed_refs();
721         for (list = packed_ref_list; list; list = list->next) {
722                 if (!strcmp(refname, list->name)) {
723                         found = 1;
724                         break;
725                 }
726         }
727         if (!found)
728                 return 0;
729         fd = hold_lock_file_for_update(&packlock, git_path("packed-refs"), 0);
730         if (fd < 0)
731                 return error("cannot delete '%s' from packed refs", refname);
732
733         for (list = packed_ref_list; list; list = list->next) {
734                 char line[PATH_MAX + 100];
735                 int len;
736
737                 if (!strcmp(refname, list->name))
738                         continue;
739                 len = snprintf(line, sizeof(line), "%s %s\n",
740                                sha1_to_hex(list->sha1), list->name);
741                 /* this should not happen but just being defensive */
742                 if (len > sizeof(line))
743                         die("too long a refname '%s'", list->name);
744                 write_or_die(fd, line, len);
745         }
746         return commit_lock_file(&packlock);
747 }
748
749 int delete_ref(const char *refname, unsigned char *sha1)
750 {
751         struct ref_lock *lock;
752         int err, i, ret = 0, flag = 0;
753
754         lock = lock_ref_sha1_basic(refname, sha1, &flag);
755         if (!lock)
756                 return 1;
757         if (!(flag & REF_ISPACKED)) {
758                 /* loose */
759                 i = strlen(lock->lk->filename) - 5; /* .lock */
760                 lock->lk->filename[i] = 0;
761                 err = unlink(lock->lk->filename);
762                 if (err) {
763                         ret = 1;
764                         error("unlink(%s) failed: %s",
765                               lock->lk->filename, strerror(errno));
766                 }
767                 lock->lk->filename[i] = '.';
768         }
769         /* removing the loose one could have resurrected an earlier
770          * packed one.  Also, if it was not loose we need to repack
771          * without it.
772          */
773         ret |= repack_without_ref(refname);
774
775         err = unlink(lock->log_file);
776         if (err && errno != ENOENT)
777                 fprintf(stderr, "warning: unlink(%s) failed: %s",
778                         lock->log_file, strerror(errno));
779         invalidate_cached_refs();
780         unlock_ref(lock);
781         return ret;
782 }
783
784 int rename_ref(const char *oldref, const char *newref, const char *logmsg)
785 {
786         static const char renamed_ref[] = "RENAMED-REF";
787         unsigned char sha1[20], orig_sha1[20];
788         int flag = 0, logmoved = 0;
789         struct ref_lock *lock;
790         struct stat loginfo;
791         int log = !lstat(git_path("logs/%s", oldref), &loginfo);
792
793         if (S_ISLNK(loginfo.st_mode))
794                 return error("reflog for %s is a symlink", oldref);
795
796         if (!resolve_ref(oldref, orig_sha1, 1, &flag))
797                 return error("refname %s not found", oldref);
798
799         if (!is_refname_available(newref, oldref, get_packed_refs(), 0))
800                 return 1;
801
802         if (!is_refname_available(newref, oldref, get_loose_refs(), 0))
803                 return 1;
804
805         lock = lock_ref_sha1_basic(renamed_ref, NULL, NULL);
806         if (!lock)
807                 return error("unable to lock %s", renamed_ref);
808         lock->force_write = 1;
809         if (write_ref_sha1(lock, orig_sha1, logmsg))
810                 return error("unable to save current sha1 in %s", renamed_ref);
811
812         if (log && rename(git_path("logs/%s", oldref), git_path("tmp-renamed-log")))
813                 return error("unable to move logfile logs/%s to tmp-renamed-log: %s",
814                         oldref, strerror(errno));
815
816         if (delete_ref(oldref, orig_sha1)) {
817                 error("unable to delete old %s", oldref);
818                 goto rollback;
819         }
820
821         if (resolve_ref(newref, sha1, 1, &flag) && delete_ref(newref, sha1)) {
822                 if (errno==EISDIR) {
823                         if (remove_empty_directories(git_path("%s", newref))) {
824                                 error("Directory not empty: %s", newref);
825                                 goto rollback;
826                         }
827                 } else {
828                         error("unable to delete existing %s", newref);
829                         goto rollback;
830                 }
831         }
832
833         if (log && safe_create_leading_directories(git_path("logs/%s", newref))) {
834                 error("unable to create directory for %s", newref);
835                 goto rollback;
836         }
837
838  retry:
839         if (log && rename(git_path("tmp-renamed-log"), git_path("logs/%s", newref))) {
840                 if (errno==EISDIR) {
841                         if (remove_empty_directories(git_path("logs/%s", newref))) {
842                                 error("Directory not empty: logs/%s", newref);
843                                 goto rollback;
844                         }
845                         goto retry;
846                 } else {
847                         error("unable to move logfile tmp-renamed-log to logs/%s: %s",
848                                 newref, strerror(errno));
849                         goto rollback;
850                 }
851         }
852         logmoved = log;
853
854         lock = lock_ref_sha1_basic(newref, NULL, NULL);
855         if (!lock) {
856                 error("unable to lock %s for update", newref);
857                 goto rollback;
858         }
859
860         lock->force_write = 1;
861         hashcpy(lock->old_sha1, orig_sha1);
862         if (write_ref_sha1(lock, orig_sha1, logmsg)) {
863                 error("unable to write current sha1 into %s", newref);
864                 goto rollback;
865         }
866
867         if (!strncmp(oldref, "refs/heads/", 11) &&
868                         !strncmp(newref, "refs/heads/", 11)) {
869                 char oldsection[1024], newsection[1024];
870
871                 snprintf(oldsection, 1024, "branch.%s", oldref + 11);
872                 snprintf(newsection, 1024, "branch.%s", newref + 11);
873                 if (git_config_rename_section(oldsection, newsection) < 0)
874                         return 1;
875         }
876
877         return 0;
878
879  rollback:
880         lock = lock_ref_sha1_basic(oldref, NULL, NULL);
881         if (!lock) {
882                 error("unable to lock %s for rollback", oldref);
883                 goto rollbacklog;
884         }
885
886         lock->force_write = 1;
887         flag = log_all_ref_updates;
888         log_all_ref_updates = 0;
889         if (write_ref_sha1(lock, orig_sha1, NULL))
890                 error("unable to write current sha1 into %s", oldref);
891         log_all_ref_updates = flag;
892
893  rollbacklog:
894         if (logmoved && rename(git_path("logs/%s", newref), git_path("logs/%s", oldref)))
895                 error("unable to restore logfile %s from %s: %s",
896                         oldref, newref, strerror(errno));
897         if (!logmoved && log &&
898             rename(git_path("tmp-renamed-log"), git_path("logs/%s", oldref)))
899                 error("unable to restore logfile %s from tmp-renamed-log: %s",
900                         oldref, strerror(errno));
901
902         return 1;
903 }
904
905 void unlock_ref(struct ref_lock *lock)
906 {
907         if (lock->lock_fd >= 0) {
908                 close(lock->lock_fd);
909                 /* Do not free lock->lk -- atexit() still looks at them */
910                 if (lock->lk)
911                         rollback_lock_file(lock->lk);
912         }
913         free(lock->ref_name);
914         free(lock->log_file);
915         free(lock);
916 }
917
918 static int log_ref_write(struct ref_lock *lock,
919         const unsigned char *sha1, const char *msg)
920 {
921         int logfd, written, oflags = O_APPEND | O_WRONLY;
922         unsigned maxlen, len;
923         char *logrec;
924         const char *committer;
925
926         if (log_all_ref_updates &&
927             (!strncmp(lock->ref_name, "refs/heads/", 11) ||
928              !strncmp(lock->ref_name, "refs/remotes/", 13))) {
929                 if (safe_create_leading_directories(lock->log_file) < 0)
930                         return error("unable to create directory for %s",
931                                 lock->log_file);
932                 oflags |= O_CREAT;
933         }
934
935         logfd = open(lock->log_file, oflags, 0666);
936         if (logfd < 0) {
937                 if (!(oflags & O_CREAT) && errno == ENOENT)
938                         return 0;
939
940                 if ((oflags & O_CREAT) && errno == EISDIR) {
941                         if (remove_empty_directories(lock->log_file)) {
942                                 return error("There are still logs under '%s'",
943                                              lock->log_file);
944                         }
945                         logfd = open(lock->log_file, oflags, 0666);
946                 }
947
948                 if (logfd < 0)
949                         return error("Unable to append to %s: %s",
950                                      lock->log_file, strerror(errno));
951         }
952
953         committer = git_committer_info(1);
954         if (msg) {
955                 maxlen = strlen(committer) + strlen(msg) + 2*40 + 5;
956                 logrec = xmalloc(maxlen);
957                 len = snprintf(logrec, maxlen, "%s %s %s\t%s\n",
958                         sha1_to_hex(lock->old_sha1),
959                         sha1_to_hex(sha1),
960                         committer,
961                         msg);
962         }
963         else {
964                 maxlen = strlen(committer) + 2*40 + 4;
965                 logrec = xmalloc(maxlen);
966                 len = snprintf(logrec, maxlen, "%s %s %s\n",
967                         sha1_to_hex(lock->old_sha1),
968                         sha1_to_hex(sha1),
969                         committer);
970         }
971         written = len <= maxlen ? write_in_full(logfd, logrec, len) : -1;
972         free(logrec);
973         close(logfd);
974         if (written != len)
975                 return error("Unable to append to %s", lock->log_file);
976         return 0;
977 }
978
979 int write_ref_sha1(struct ref_lock *lock,
980         const unsigned char *sha1, const char *logmsg)
981 {
982         static char term = '\n';
983
984         if (!lock)
985                 return -1;
986         if (!lock->force_write && !hashcmp(lock->old_sha1, sha1)) {
987                 unlock_ref(lock);
988                 return 0;
989         }
990         if (write_in_full(lock->lock_fd, sha1_to_hex(sha1), 40) != 40 ||
991             write_in_full(lock->lock_fd, &term, 1) != 1
992                 || close(lock->lock_fd) < 0) {
993                 error("Couldn't write %s", lock->lk->filename);
994                 unlock_ref(lock);
995                 return -1;
996         }
997         invalidate_cached_refs();
998         if (log_ref_write(lock, sha1, logmsg) < 0) {
999                 unlock_ref(lock);
1000                 return -1;
1001         }
1002         if (commit_lock_file(lock->lk)) {
1003                 error("Couldn't set %s", lock->ref_name);
1004                 unlock_ref(lock);
1005                 return -1;
1006         }
1007         lock->lock_fd = -1;
1008         unlock_ref(lock);
1009         return 0;
1010 }
1011
1012 int read_ref_at(const char *ref, unsigned long at_time, int cnt, unsigned char *sha1)
1013 {
1014         const char *logfile, *logdata, *logend, *rec, *lastgt, *lastrec;
1015         char *tz_c;
1016         int logfd, tz, reccnt = 0;
1017         struct stat st;
1018         unsigned long date;
1019         unsigned char logged_sha1[20];
1020
1021         logfile = git_path("logs/%s", ref);
1022         logfd = open(logfile, O_RDONLY, 0);
1023         if (logfd < 0)
1024                 die("Unable to read log %s: %s", logfile, strerror(errno));
1025         fstat(logfd, &st);
1026         if (!st.st_size)
1027                 die("Log %s is empty.", logfile);
1028         logdata = xmmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, logfd, 0);
1029         close(logfd);
1030
1031         lastrec = NULL;
1032         rec = logend = logdata + st.st_size;
1033         while (logdata < rec) {
1034                 reccnt++;
1035                 if (logdata < rec && *(rec-1) == '\n')
1036                         rec--;
1037                 lastgt = NULL;
1038                 while (logdata < rec && *(rec-1) != '\n') {
1039                         rec--;
1040                         if (*rec == '>')
1041                                 lastgt = rec;
1042                 }
1043                 if (!lastgt)
1044                         die("Log %s is corrupt.", logfile);
1045                 date = strtoul(lastgt + 1, &tz_c, 10);
1046                 if (date <= at_time || cnt == 0) {
1047                         if (lastrec) {
1048                                 if (get_sha1_hex(lastrec, logged_sha1))
1049                                         die("Log %s is corrupt.", logfile);
1050                                 if (get_sha1_hex(rec + 41, sha1))
1051                                         die("Log %s is corrupt.", logfile);
1052                                 if (hashcmp(logged_sha1, sha1)) {
1053                                         tz = strtoul(tz_c, NULL, 10);
1054                                         fprintf(stderr,
1055                                                 "warning: Log %s has gap after %s.\n",
1056                                                 logfile, show_rfc2822_date(date, tz));
1057                                 }
1058                         }
1059                         else if (date == at_time) {
1060                                 if (get_sha1_hex(rec + 41, sha1))
1061                                         die("Log %s is corrupt.", logfile);
1062                         }
1063                         else {
1064                                 if (get_sha1_hex(rec + 41, logged_sha1))
1065                                         die("Log %s is corrupt.", logfile);
1066                                 if (hashcmp(logged_sha1, sha1)) {
1067                                         tz = strtoul(tz_c, NULL, 10);
1068                                         fprintf(stderr,
1069                                                 "warning: Log %s unexpectedly ended on %s.\n",
1070                                                 logfile, show_rfc2822_date(date, tz));
1071                                 }
1072                         }
1073                         munmap((void*)logdata, st.st_size);
1074                         return 0;
1075                 }
1076                 lastrec = rec;
1077                 if (cnt > 0)
1078                         cnt--;
1079         }
1080
1081         rec = logdata;
1082         while (rec < logend && *rec != '>' && *rec != '\n')
1083                 rec++;
1084         if (rec == logend || *rec == '\n')
1085                 die("Log %s is corrupt.", logfile);
1086         date = strtoul(rec + 1, &tz_c, 10);
1087         tz = strtoul(tz_c, NULL, 10);
1088         if (get_sha1_hex(logdata, sha1))
1089                 die("Log %s is corrupt.", logfile);
1090         munmap((void*)logdata, st.st_size);
1091         if (at_time)
1092                 fprintf(stderr, "warning: Log %s only goes back to %s.\n",
1093                         logfile, show_rfc2822_date(date, tz));
1094         else
1095                 fprintf(stderr, "warning: Log %s only has %d entries.\n",
1096                         logfile, reccnt);
1097         return 0;
1098 }
1099
1100 void for_each_reflog_ent(const char *ref, each_reflog_ent_fn fn, void *cb_data)
1101 {
1102         const char *logfile;
1103         FILE *logfp;
1104         char buf[1024];
1105
1106         logfile = git_path("logs/%s", ref);
1107         logfp = fopen(logfile, "r");
1108         if (!logfp)
1109                 return;
1110         while (fgets(buf, sizeof(buf), logfp)) {
1111                 unsigned char osha1[20], nsha1[20];
1112                 int len;
1113
1114                 /* old SP new SP name <email> SP time TAB msg LF */
1115                 len = strlen(buf);
1116                 if (len < 83 || buf[len-1] != '\n' ||
1117                     get_sha1_hex(buf, osha1) || buf[40] != ' ' ||
1118                     get_sha1_hex(buf + 41, nsha1) || buf[81] != ' ')
1119                         continue; /* corrupt? */
1120                 fn(osha1, nsha1, buf+82, cb_data);
1121         }
1122         fclose(logfp);
1123 }
1124