resolve_ref(): report breakage to the caller without warning
[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=0x01, ISPACKED=0x02 and ISBROKEN=0x04 are public interfaces */
8 #define REF_KNOWS_PEELED 0x10
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         if (check_refname_format(name, REFNAME_ALLOW_ONELEVEL|REFNAME_DOT_COMPONENT))
59                 die("Reference has invalid format: '%s'", name);
60         memcpy(entry->name, name, len);
61         entry->flag = flag;
62         entry->next = list;
63         if (new_entry)
64                 *new_entry = entry;
65         return entry;
66 }
67
68 /* merge sort the ref list */
69 static struct ref_list *sort_ref_list(struct ref_list *list)
70 {
71         int psize, qsize, last_merge_count, cmp;
72         struct ref_list *p, *q, *l, *e;
73         struct ref_list *new_list = list;
74         int k = 1;
75         int merge_count = 0;
76
77         if (!list)
78                 return list;
79
80         do {
81                 last_merge_count = merge_count;
82                 merge_count = 0;
83
84                 psize = 0;
85
86                 p = new_list;
87                 q = new_list;
88                 new_list = NULL;
89                 l = NULL;
90
91                 while (p) {
92                         merge_count++;
93
94                         while (psize < k && q->next) {
95                                 q = q->next;
96                                 psize++;
97                         }
98                         qsize = k;
99
100                         while ((psize > 0) || (qsize > 0 && q)) {
101                                 if (qsize == 0 || !q) {
102                                         e = p;
103                                         p = p->next;
104                                         psize--;
105                                 } else if (psize == 0) {
106                                         e = q;
107                                         q = q->next;
108                                         qsize--;
109                                 } else {
110                                         cmp = strcmp(q->name, p->name);
111                                         if (cmp < 0) {
112                                                 e = q;
113                                                 q = q->next;
114                                                 qsize--;
115                                         } else if (cmp > 0) {
116                                                 e = p;
117                                                 p = p->next;
118                                                 psize--;
119                                         } else {
120                                                 if (hashcmp(q->sha1, p->sha1))
121                                                         die("Duplicated ref, and SHA1s don't match: %s",
122                                                             q->name);
123                                                 warning("Duplicated ref: %s", q->name);
124                                                 e = q;
125                                                 q = q->next;
126                                                 qsize--;
127                                                 free(e);
128                                                 e = p;
129                                                 p = p->next;
130                                                 psize--;
131                                         }
132                                 }
133
134                                 e->next = NULL;
135
136                                 if (l)
137                                         l->next = e;
138                                 if (!new_list)
139                                         new_list = e;
140                                 l = e;
141                         }
142
143                         p = q;
144                 };
145
146                 k = k * 2;
147         } while ((last_merge_count != merge_count) || (last_merge_count != 1));
148
149         return new_list;
150 }
151
152 /*
153  * Future: need to be in "struct repository"
154  * when doing a full libification.
155  */
156 static struct cached_refs {
157         char did_loose;
158         char did_packed;
159         struct ref_list *loose;
160         struct ref_list *packed;
161 } cached_refs, submodule_refs;
162 static struct ref_list *current_ref;
163
164 static struct ref_list *extra_refs;
165
166 static void free_ref_list(struct ref_list *list)
167 {
168         struct ref_list *next;
169         for ( ; list; list = next) {
170                 next = list->next;
171                 free(list);
172         }
173 }
174
175 static void invalidate_cached_refs(void)
176 {
177         struct cached_refs *ca = &cached_refs;
178
179         if (ca->did_loose && ca->loose)
180                 free_ref_list(ca->loose);
181         if (ca->did_packed && ca->packed)
182                 free_ref_list(ca->packed);
183         ca->loose = ca->packed = NULL;
184         ca->did_loose = ca->did_packed = 0;
185 }
186
187 static void read_packed_refs(FILE *f, struct cached_refs *cached_refs)
188 {
189         struct ref_list *list = NULL;
190         struct ref_list *last = NULL;
191         char refline[PATH_MAX];
192         int flag = REF_ISPACKED;
193
194         while (fgets(refline, sizeof(refline), f)) {
195                 unsigned char sha1[20];
196                 const char *name;
197                 static const char header[] = "# pack-refs with:";
198
199                 if (!strncmp(refline, header, sizeof(header)-1)) {
200                         const char *traits = refline + sizeof(header) - 1;
201                         if (strstr(traits, " peeled "))
202                                 flag |= REF_KNOWS_PEELED;
203                         /* perhaps other traits later as well */
204                         continue;
205                 }
206
207                 name = parse_ref_line(refline, sha1);
208                 if (name) {
209                         list = add_ref(name, sha1, flag, list, &last);
210                         continue;
211                 }
212                 if (last &&
213                     refline[0] == '^' &&
214                     strlen(refline) == 42 &&
215                     refline[41] == '\n' &&
216                     !get_sha1_hex(refline + 1, sha1))
217                         hashcpy(last->peeled, sha1);
218         }
219         cached_refs->packed = sort_ref_list(list);
220 }
221
222 void add_extra_ref(const char *name, const unsigned char *sha1, int flag)
223 {
224         extra_refs = add_ref(name, sha1, flag, extra_refs, NULL);
225 }
226
227 void clear_extra_refs(void)
228 {
229         free_ref_list(extra_refs);
230         extra_refs = NULL;
231 }
232
233 static struct ref_list *get_packed_refs(const char *submodule)
234 {
235         const char *packed_refs_file;
236         struct cached_refs *refs;
237
238         if (submodule) {
239                 packed_refs_file = git_path_submodule(submodule, "packed-refs");
240                 refs = &submodule_refs;
241                 free_ref_list(refs->packed);
242         } else {
243                 packed_refs_file = git_path("packed-refs");
244                 refs = &cached_refs;
245         }
246
247         if (!refs->did_packed || submodule) {
248                 FILE *f = fopen(packed_refs_file, "r");
249                 refs->packed = NULL;
250                 if (f) {
251                         read_packed_refs(f, refs);
252                         fclose(f);
253                 }
254                 refs->did_packed = 1;
255         }
256         return refs->packed;
257 }
258
259 static struct ref_list *get_ref_dir(const char *submodule, const char *base,
260                                     struct ref_list *list)
261 {
262         DIR *dir;
263         const char *path;
264
265         if (submodule)
266                 path = git_path_submodule(submodule, "%s", base);
267         else
268                 path = git_path("%s", base);
269
270
271         dir = opendir(path);
272
273         if (dir) {
274                 struct dirent *de;
275                 int baselen = strlen(base);
276                 char *ref = xmalloc(baselen + 257);
277
278                 memcpy(ref, base, baselen);
279                 if (baselen && base[baselen-1] != '/')
280                         ref[baselen++] = '/';
281
282                 while ((de = readdir(dir)) != NULL) {
283                         unsigned char sha1[20];
284                         struct stat st;
285                         int flag;
286                         int namelen;
287                         const char *refdir;
288
289                         if (de->d_name[0] == '.')
290                                 continue;
291                         namelen = strlen(de->d_name);
292                         if (namelen > 255)
293                                 continue;
294                         if (has_extension(de->d_name, ".lock"))
295                                 continue;
296                         memcpy(ref + baselen, de->d_name, namelen+1);
297                         refdir = submodule
298                                 ? git_path_submodule(submodule, "%s", ref)
299                                 : git_path("%s", ref);
300                         if (stat(refdir, &st) < 0)
301                                 continue;
302                         if (S_ISDIR(st.st_mode)) {
303                                 list = get_ref_dir(submodule, ref, list);
304                                 continue;
305                         }
306                         if (submodule) {
307                                 hashclr(sha1);
308                                 flag = 0;
309                                 if (resolve_gitlink_ref(submodule, ref, sha1) < 0) {
310                                         hashclr(sha1);
311                                         flag |= REF_ISBROKEN;
312                                 }
313                         } else
314                                 if (!resolve_ref(ref, sha1, 1, &flag)) {
315                                         hashclr(sha1);
316                                         flag |= REF_ISBROKEN;
317                                 }
318                         list = add_ref(ref, sha1, flag, list, NULL);
319                 }
320                 free(ref);
321                 closedir(dir);
322         }
323         return sort_ref_list(list);
324 }
325
326 struct warn_if_dangling_data {
327         FILE *fp;
328         const char *refname;
329         const char *msg_fmt;
330 };
331
332 static int warn_if_dangling_symref(const char *refname, const unsigned char *sha1,
333                                    int flags, void *cb_data)
334 {
335         struct warn_if_dangling_data *d = cb_data;
336         const char *resolves_to;
337         unsigned char junk[20];
338
339         if (!(flags & REF_ISSYMREF))
340                 return 0;
341
342         resolves_to = resolve_ref(refname, junk, 0, NULL);
343         if (!resolves_to || strcmp(resolves_to, d->refname))
344                 return 0;
345
346         fprintf(d->fp, d->msg_fmt, refname);
347         return 0;
348 }
349
350 void warn_dangling_symref(FILE *fp, const char *msg_fmt, const char *refname)
351 {
352         struct warn_if_dangling_data data;
353
354         data.fp = fp;
355         data.refname = refname;
356         data.msg_fmt = msg_fmt;
357         for_each_rawref(warn_if_dangling_symref, &data);
358 }
359
360 static struct ref_list *get_loose_refs(const char *submodule)
361 {
362         if (submodule) {
363                 free_ref_list(submodule_refs.loose);
364                 submodule_refs.loose = get_ref_dir(submodule, "refs", NULL);
365                 return submodule_refs.loose;
366         }
367
368         if (!cached_refs.did_loose) {
369                 cached_refs.loose = get_ref_dir(NULL, "refs", NULL);
370                 cached_refs.did_loose = 1;
371         }
372         return cached_refs.loose;
373 }
374
375 /* We allow "recursive" symbolic refs. Only within reason, though */
376 #define MAXDEPTH 5
377 #define MAXREFLEN (1024)
378
379 static int resolve_gitlink_packed_ref(char *name, int pathlen, const char *refname, unsigned char *result)
380 {
381         FILE *f;
382         struct cached_refs refs;
383         struct ref_list *ref;
384         int retval;
385
386         strcpy(name + pathlen, "packed-refs");
387         f = fopen(name, "r");
388         if (!f)
389                 return -1;
390         read_packed_refs(f, &refs);
391         fclose(f);
392         ref = refs.packed;
393         retval = -1;
394         while (ref) {
395                 if (!strcmp(ref->name, refname)) {
396                         retval = 0;
397                         memcpy(result, ref->sha1, 20);
398                         break;
399                 }
400                 ref = ref->next;
401         }
402         free_ref_list(refs.packed);
403         return retval;
404 }
405
406 static int resolve_gitlink_ref_recursive(char *name, int pathlen, const char *refname, unsigned char *result, int recursion)
407 {
408         int fd, len = strlen(refname);
409         char buffer[128], *p;
410
411         if (recursion > MAXDEPTH || len > MAXREFLEN)
412                 return -1;
413         memcpy(name + pathlen, refname, len+1);
414         fd = open(name, O_RDONLY);
415         if (fd < 0)
416                 return resolve_gitlink_packed_ref(name, pathlen, refname, result);
417
418         len = read(fd, buffer, sizeof(buffer)-1);
419         close(fd);
420         if (len < 0)
421                 return -1;
422         while (len && isspace(buffer[len-1]))
423                 len--;
424         buffer[len] = 0;
425
426         /* Was it a detached head or an old-fashioned symlink? */
427         if (!get_sha1_hex(buffer, result))
428                 return 0;
429
430         /* Symref? */
431         if (strncmp(buffer, "ref:", 4))
432                 return -1;
433         p = buffer + 4;
434         while (isspace(*p))
435                 p++;
436
437         return resolve_gitlink_ref_recursive(name, pathlen, p, result, recursion+1);
438 }
439
440 int resolve_gitlink_ref(const char *path, const char *refname, unsigned char *result)
441 {
442         int len = strlen(path), retval;
443         char *gitdir;
444         const char *tmp;
445
446         while (len && path[len-1] == '/')
447                 len--;
448         if (!len)
449                 return -1;
450         gitdir = xmalloc(len + MAXREFLEN + 8);
451         memcpy(gitdir, path, len);
452         memcpy(gitdir + len, "/.git", 6);
453         len += 5;
454
455         tmp = read_gitfile(gitdir);
456         if (tmp) {
457                 free(gitdir);
458                 len = strlen(tmp);
459                 gitdir = xmalloc(len + MAXREFLEN + 3);
460                 memcpy(gitdir, tmp, len);
461         }
462         gitdir[len] = '/';
463         gitdir[++len] = '\0';
464         retval = resolve_gitlink_ref_recursive(gitdir, len, refname, result, 0);
465         free(gitdir);
466         return retval;
467 }
468
469 /*
470  * Try to read ref from the packed references.  On success, set sha1
471  * and return 0; otherwise, return -1.
472  */
473 static int get_packed_ref(const char *ref, unsigned char *sha1)
474 {
475         struct ref_list *list = get_packed_refs(NULL);
476         while (list) {
477                 if (!strcmp(ref, list->name)) {
478                         hashcpy(sha1, list->sha1);
479                         return 0;
480                 }
481                 list = list->next;
482         }
483         return -1;
484 }
485
486 const char *resolve_ref(const char *ref, unsigned char *sha1, int reading, int *flag)
487 {
488         int depth = MAXDEPTH;
489         ssize_t len;
490         char buffer[256];
491         static char ref_buffer[256];
492
493         if (flag)
494                 *flag = 0;
495
496         if (check_refname_format(ref, REFNAME_ALLOW_ONELEVEL))
497                 return NULL;
498
499         for (;;) {
500                 char path[PATH_MAX];
501                 struct stat st;
502                 char *buf;
503                 int fd;
504
505                 if (--depth < 0)
506                         return NULL;
507
508                 git_snpath(path, sizeof(path), "%s", ref);
509
510                 if (lstat(path, &st) < 0) {
511                         if (errno != ENOENT)
512                                 return NULL;
513                         /*
514                          * The loose reference file does not exist;
515                          * check for a packed reference.
516                          */
517                         if (!get_packed_ref(ref, sha1)) {
518                                 if (flag)
519                                         *flag |= REF_ISPACKED;
520                                 return ref;
521                         }
522                         /* The reference is not a packed reference, either. */
523                         if (reading) {
524                                 return NULL;
525                         } else {
526                                 hashclr(sha1);
527                                 return ref;
528                         }
529                 }
530
531                 /* Follow "normalized" - ie "refs/.." symlinks by hand */
532                 if (S_ISLNK(st.st_mode)) {
533                         len = readlink(path, buffer, sizeof(buffer)-1);
534                         if (len < 0)
535                                 return NULL;
536                         buffer[len] = 0;
537                         if (!prefixcmp(buffer, "refs/") &&
538                                         !check_refname_format(buffer, 0)) {
539                                 strcpy(ref_buffer, buffer);
540                                 ref = ref_buffer;
541                                 if (flag)
542                                         *flag |= REF_ISSYMREF;
543                                 continue;
544                         }
545                 }
546
547                 /* Is it a directory? */
548                 if (S_ISDIR(st.st_mode)) {
549                         errno = EISDIR;
550                         return NULL;
551                 }
552
553                 /*
554                  * Anything else, just open it and try to use it as
555                  * a ref
556                  */
557                 fd = open(path, O_RDONLY);
558                 if (fd < 0)
559                         return NULL;
560                 len = read_in_full(fd, buffer, sizeof(buffer)-1);
561                 close(fd);
562                 if (len < 0)
563                         return NULL;
564                 while (len && isspace(buffer[len-1]))
565                         len--;
566                 buffer[len] = '\0';
567
568                 /*
569                  * Is it a symbolic ref?
570                  */
571                 if (prefixcmp(buffer, "ref:"))
572                         break;
573                 if (flag)
574                         *flag |= REF_ISSYMREF;
575                 buf = buffer + 4;
576                 while (isspace(*buf))
577                         buf++;
578                 if (check_refname_format(buf, REFNAME_ALLOW_ONELEVEL)) {
579                         if (flag)
580                                 *flag |= REF_ISBROKEN;
581                         return NULL;
582                 }
583                 ref = strcpy(ref_buffer, buf);
584         }
585         /* Please note that FETCH_HEAD has a second line containing other data. */
586         if (get_sha1_hex(buffer, sha1) || (buffer[40] != '\0' && !isspace(buffer[40]))) {
587                 if (flag)
588                         *flag |= REF_ISBROKEN;
589                 return NULL;
590         }
591         return ref;
592 }
593
594 /* The argument to filter_refs */
595 struct ref_filter {
596         const char *pattern;
597         each_ref_fn *fn;
598         void *cb_data;
599 };
600
601 int read_ref(const char *ref, unsigned char *sha1)
602 {
603         if (resolve_ref(ref, sha1, 1, NULL))
604                 return 0;
605         return -1;
606 }
607
608 #define DO_FOR_EACH_INCLUDE_BROKEN 01
609 static int do_one_ref(const char *base, each_ref_fn fn, int trim,
610                       int flags, void *cb_data, struct ref_list *entry)
611 {
612         if (prefixcmp(entry->name, base))
613                 return 0;
614
615         if (!(flags & DO_FOR_EACH_INCLUDE_BROKEN)) {
616                 if (entry->flag & REF_ISBROKEN)
617                         return 0; /* ignore broken refs e.g. dangling symref */
618                 if (!has_sha1_file(entry->sha1)) {
619                         error("%s does not point to a valid object!", entry->name);
620                         return 0;
621                 }
622         }
623         current_ref = entry;
624         return fn(entry->name + trim, entry->sha1, entry->flag, cb_data);
625 }
626
627 static int filter_refs(const char *ref, const unsigned char *sha, int flags,
628         void *data)
629 {
630         struct ref_filter *filter = (struct ref_filter *)data;
631         if (fnmatch(filter->pattern, ref, 0))
632                 return 0;
633         return filter->fn(ref, sha, flags, filter->cb_data);
634 }
635
636 int peel_ref(const char *ref, unsigned char *sha1)
637 {
638         int flag;
639         unsigned char base[20];
640         struct object *o;
641
642         if (current_ref && (current_ref->name == ref
643                 || !strcmp(current_ref->name, ref))) {
644                 if (current_ref->flag & REF_KNOWS_PEELED) {
645                         hashcpy(sha1, current_ref->peeled);
646                         return 0;
647                 }
648                 hashcpy(base, current_ref->sha1);
649                 goto fallback;
650         }
651
652         if (!resolve_ref(ref, base, 1, &flag))
653                 return -1;
654
655         if ((flag & REF_ISPACKED)) {
656                 struct ref_list *list = get_packed_refs(NULL);
657
658                 while (list) {
659                         if (!strcmp(list->name, ref)) {
660                                 if (list->flag & REF_KNOWS_PEELED) {
661                                         hashcpy(sha1, list->peeled);
662                                         return 0;
663                                 }
664                                 /* older pack-refs did not leave peeled ones */
665                                 break;
666                         }
667                         list = list->next;
668                 }
669         }
670
671 fallback:
672         o = parse_object(base);
673         if (o && o->type == OBJ_TAG) {
674                 o = deref_tag(o, ref, 0);
675                 if (o) {
676                         hashcpy(sha1, o->sha1);
677                         return 0;
678                 }
679         }
680         return -1;
681 }
682
683 static int do_for_each_ref(const char *submodule, const char *base, each_ref_fn fn,
684                            int trim, int flags, void *cb_data)
685 {
686         int retval = 0;
687         struct ref_list *packed = get_packed_refs(submodule);
688         struct ref_list *loose = get_loose_refs(submodule);
689
690         struct ref_list *extra;
691
692         for (extra = extra_refs; extra; extra = extra->next)
693                 retval = do_one_ref(base, fn, trim, flags, cb_data, extra);
694
695         while (packed && loose) {
696                 struct ref_list *entry;
697                 int cmp = strcmp(packed->name, loose->name);
698                 if (!cmp) {
699                         packed = packed->next;
700                         continue;
701                 }
702                 if (cmp > 0) {
703                         entry = loose;
704                         loose = loose->next;
705                 } else {
706                         entry = packed;
707                         packed = packed->next;
708                 }
709                 retval = do_one_ref(base, fn, trim, flags, cb_data, entry);
710                 if (retval)
711                         goto end_each;
712         }
713
714         for (packed = packed ? packed : loose; packed; packed = packed->next) {
715                 retval = do_one_ref(base, fn, trim, flags, cb_data, packed);
716                 if (retval)
717                         goto end_each;
718         }
719
720 end_each:
721         current_ref = NULL;
722         return retval;
723 }
724
725
726 static int do_head_ref(const char *submodule, each_ref_fn fn, void *cb_data)
727 {
728         unsigned char sha1[20];
729         int flag;
730
731         if (submodule) {
732                 if (resolve_gitlink_ref(submodule, "HEAD", sha1) == 0)
733                         return fn("HEAD", sha1, 0, cb_data);
734
735                 return 0;
736         }
737
738         if (resolve_ref("HEAD", sha1, 1, &flag))
739                 return fn("HEAD", sha1, flag, cb_data);
740
741         return 0;
742 }
743
744 int head_ref(each_ref_fn fn, void *cb_data)
745 {
746         return do_head_ref(NULL, fn, cb_data);
747 }
748
749 int head_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
750 {
751         return do_head_ref(submodule, fn, cb_data);
752 }
753
754 int for_each_ref(each_ref_fn fn, void *cb_data)
755 {
756         return do_for_each_ref(NULL, "", fn, 0, 0, cb_data);
757 }
758
759 int for_each_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
760 {
761         return do_for_each_ref(submodule, "", fn, 0, 0, cb_data);
762 }
763
764 int for_each_ref_in(const char *prefix, each_ref_fn fn, void *cb_data)
765 {
766         return do_for_each_ref(NULL, prefix, fn, strlen(prefix), 0, cb_data);
767 }
768
769 int for_each_ref_in_submodule(const char *submodule, const char *prefix,
770                 each_ref_fn fn, void *cb_data)
771 {
772         return do_for_each_ref(submodule, prefix, fn, strlen(prefix), 0, cb_data);
773 }
774
775 int for_each_tag_ref(each_ref_fn fn, void *cb_data)
776 {
777         return for_each_ref_in("refs/tags/", fn, cb_data);
778 }
779
780 int for_each_tag_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
781 {
782         return for_each_ref_in_submodule(submodule, "refs/tags/", fn, cb_data);
783 }
784
785 int for_each_branch_ref(each_ref_fn fn, void *cb_data)
786 {
787         return for_each_ref_in("refs/heads/", fn, cb_data);
788 }
789
790 int for_each_branch_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
791 {
792         return for_each_ref_in_submodule(submodule, "refs/heads/", fn, cb_data);
793 }
794
795 int for_each_remote_ref(each_ref_fn fn, void *cb_data)
796 {
797         return for_each_ref_in("refs/remotes/", fn, cb_data);
798 }
799
800 int for_each_remote_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
801 {
802         return for_each_ref_in_submodule(submodule, "refs/remotes/", fn, cb_data);
803 }
804
805 int for_each_replace_ref(each_ref_fn fn, void *cb_data)
806 {
807         return do_for_each_ref(NULL, "refs/replace/", fn, 13, 0, cb_data);
808 }
809
810 int head_ref_namespaced(each_ref_fn fn, void *cb_data)
811 {
812         struct strbuf buf = STRBUF_INIT;
813         int ret = 0;
814         unsigned char sha1[20];
815         int flag;
816
817         strbuf_addf(&buf, "%sHEAD", get_git_namespace());
818         if (resolve_ref(buf.buf, sha1, 1, &flag))
819                 ret = fn(buf.buf, sha1, flag, cb_data);
820         strbuf_release(&buf);
821
822         return ret;
823 }
824
825 int for_each_namespaced_ref(each_ref_fn fn, void *cb_data)
826 {
827         struct strbuf buf = STRBUF_INIT;
828         int ret;
829         strbuf_addf(&buf, "%srefs/", get_git_namespace());
830         ret = do_for_each_ref(NULL, buf.buf, fn, 0, 0, cb_data);
831         strbuf_release(&buf);
832         return ret;
833 }
834
835 int for_each_glob_ref_in(each_ref_fn fn, const char *pattern,
836         const char *prefix, void *cb_data)
837 {
838         struct strbuf real_pattern = STRBUF_INIT;
839         struct ref_filter filter;
840         int ret;
841
842         if (!prefix && prefixcmp(pattern, "refs/"))
843                 strbuf_addstr(&real_pattern, "refs/");
844         else if (prefix)
845                 strbuf_addstr(&real_pattern, prefix);
846         strbuf_addstr(&real_pattern, pattern);
847
848         if (!has_glob_specials(pattern)) {
849                 /* Append implied '/' '*' if not present. */
850                 if (real_pattern.buf[real_pattern.len - 1] != '/')
851                         strbuf_addch(&real_pattern, '/');
852                 /* No need to check for '*', there is none. */
853                 strbuf_addch(&real_pattern, '*');
854         }
855
856         filter.pattern = real_pattern.buf;
857         filter.fn = fn;
858         filter.cb_data = cb_data;
859         ret = for_each_ref(filter_refs, &filter);
860
861         strbuf_release(&real_pattern);
862         return ret;
863 }
864
865 int for_each_glob_ref(each_ref_fn fn, const char *pattern, void *cb_data)
866 {
867         return for_each_glob_ref_in(fn, pattern, NULL, cb_data);
868 }
869
870 int for_each_rawref(each_ref_fn fn, void *cb_data)
871 {
872         return do_for_each_ref(NULL, "", fn, 0,
873                                DO_FOR_EACH_INCLUDE_BROKEN, cb_data);
874 }
875
876 /*
877  * Make sure "ref" is something reasonable to have under ".git/refs/";
878  * We do not like it if:
879  *
880  * - any path component of it begins with ".", or
881  * - it has double dots "..", or
882  * - it has ASCII control character, "~", "^", ":" or SP, anywhere, or
883  * - it ends with a "/".
884  * - it ends with ".lock"
885  * - it contains a "\" (backslash)
886  */
887
888 /* Return true iff ch is not allowed in reference names. */
889 static inline int bad_ref_char(int ch)
890 {
891         if (((unsigned) ch) <= ' ' || ch == 0x7f ||
892             ch == '~' || ch == '^' || ch == ':' || ch == '\\')
893                 return 1;
894         /* 2.13 Pattern Matching Notation */
895         if (ch == '*' || ch == '?' || ch == '[') /* Unsupported */
896                 return 1;
897         return 0;
898 }
899
900 /*
901  * Try to read one refname component from the front of ref.  Return
902  * the length of the component found, or -1 if the component is not
903  * legal.
904  */
905 static int check_refname_component(const char *ref, int flags)
906 {
907         const char *cp;
908         char last = '\0';
909
910         for (cp = ref; ; cp++) {
911                 char ch = *cp;
912                 if (ch == '\0' || ch == '/')
913                         break;
914                 if (bad_ref_char(ch))
915                         return -1; /* Illegal character in refname. */
916                 if (last == '.' && ch == '.')
917                         return -1; /* Refname contains "..". */
918                 if (last == '@' && ch == '{')
919                         return -1; /* Refname contains "@{". */
920                 last = ch;
921         }
922         if (cp == ref)
923                 return -1; /* Component has zero length. */
924         if (ref[0] == '.') {
925                 if (!(flags & REFNAME_DOT_COMPONENT))
926                         return -1; /* Component starts with '.'. */
927                 /*
928                  * Even if leading dots are allowed, don't allow "."
929                  * as a component (".." is prevented by a rule above).
930                  */
931                 if (ref[1] == '\0')
932                         return -1; /* Component equals ".". */
933         }
934         if (cp - ref >= 5 && !memcmp(cp - 5, ".lock", 5))
935                 return -1; /* Refname ends with ".lock". */
936         return cp - ref;
937 }
938
939 int check_refname_format(const char *ref, int flags)
940 {
941         int component_len, component_count = 0;
942
943         while (1) {
944                 /* We are at the start of a path component. */
945                 component_len = check_refname_component(ref, flags);
946                 if (component_len < 0) {
947                         if ((flags & REFNAME_REFSPEC_PATTERN) &&
948                                         ref[0] == '*' &&
949                                         (ref[1] == '\0' || ref[1] == '/')) {
950                                 /* Accept one wildcard as a full refname component. */
951                                 flags &= ~REFNAME_REFSPEC_PATTERN;
952                                 component_len = 1;
953                         } else {
954                                 return -1;
955                         }
956                 }
957                 component_count++;
958                 if (ref[component_len] == '\0')
959                         break;
960                 /* Skip to next component. */
961                 ref += component_len + 1;
962         }
963
964         if (ref[component_len - 1] == '.')
965                 return -1; /* Refname ends with '.'. */
966         if (!(flags & REFNAME_ALLOW_ONELEVEL) && component_count < 2)
967                 return -1; /* Refname has only one component. */
968         return 0;
969 }
970
971 const char *prettify_refname(const char *name)
972 {
973         return name + (
974                 !prefixcmp(name, "refs/heads/") ? 11 :
975                 !prefixcmp(name, "refs/tags/") ? 10 :
976                 !prefixcmp(name, "refs/remotes/") ? 13 :
977                 0);
978 }
979
980 const char *ref_rev_parse_rules[] = {
981         "%.*s",
982         "refs/%.*s",
983         "refs/tags/%.*s",
984         "refs/heads/%.*s",
985         "refs/remotes/%.*s",
986         "refs/remotes/%.*s/HEAD",
987         NULL
988 };
989
990 const char *ref_fetch_rules[] = {
991         "%.*s",
992         "refs/%.*s",
993         "refs/heads/%.*s",
994         NULL
995 };
996
997 int refname_match(const char *abbrev_name, const char *full_name, const char **rules)
998 {
999         const char **p;
1000         const int abbrev_name_len = strlen(abbrev_name);
1001
1002         for (p = rules; *p; p++) {
1003                 if (!strcmp(full_name, mkpath(*p, abbrev_name_len, abbrev_name))) {
1004                         return 1;
1005                 }
1006         }
1007
1008         return 0;
1009 }
1010
1011 static struct ref_lock *verify_lock(struct ref_lock *lock,
1012         const unsigned char *old_sha1, int mustexist)
1013 {
1014         if (!resolve_ref(lock->ref_name, lock->old_sha1, mustexist, NULL)) {
1015                 error("Can't verify ref %s", lock->ref_name);
1016                 unlock_ref(lock);
1017                 return NULL;
1018         }
1019         if (hashcmp(lock->old_sha1, old_sha1)) {
1020                 error("Ref %s is at %s but expected %s", lock->ref_name,
1021                         sha1_to_hex(lock->old_sha1), sha1_to_hex(old_sha1));
1022                 unlock_ref(lock);
1023                 return NULL;
1024         }
1025         return lock;
1026 }
1027
1028 static int remove_empty_directories(const char *file)
1029 {
1030         /* we want to create a file but there is a directory there;
1031          * if that is an empty directory (or a directory that contains
1032          * only empty directories), remove them.
1033          */
1034         struct strbuf path;
1035         int result;
1036
1037         strbuf_init(&path, 20);
1038         strbuf_addstr(&path, file);
1039
1040         result = remove_dir_recursively(&path, REMOVE_DIR_EMPTY_ONLY);
1041
1042         strbuf_release(&path);
1043
1044         return result;
1045 }
1046
1047 static int is_refname_available(const char *ref, const char *oldref,
1048                                 struct ref_list *list, int quiet)
1049 {
1050         int namlen = strlen(ref); /* e.g. 'foo/bar' */
1051         while (list) {
1052                 /* list->name could be 'foo' or 'foo/bar/baz' */
1053                 if (!oldref || strcmp(oldref, list->name)) {
1054                         int len = strlen(list->name);
1055                         int cmplen = (namlen < len) ? namlen : len;
1056                         const char *lead = (namlen < len) ? list->name : ref;
1057                         if (!strncmp(ref, list->name, cmplen) &&
1058                             lead[cmplen] == '/') {
1059                                 if (!quiet)
1060                                         error("'%s' exists; cannot create '%s'",
1061                                               list->name, ref);
1062                                 return 0;
1063                         }
1064                 }
1065                 list = list->next;
1066         }
1067         return 1;
1068 }
1069
1070 /*
1071  * *string and *len will only be substituted, and *string returned (for
1072  * later free()ing) if the string passed in is a magic short-hand form
1073  * to name a branch.
1074  */
1075 static char *substitute_branch_name(const char **string, int *len)
1076 {
1077         struct strbuf buf = STRBUF_INIT;
1078         int ret = interpret_branch_name(*string, &buf);
1079
1080         if (ret == *len) {
1081                 size_t size;
1082                 *string = strbuf_detach(&buf, &size);
1083                 *len = size;
1084                 return (char *)*string;
1085         }
1086
1087         return NULL;
1088 }
1089
1090 int dwim_ref(const char *str, int len, unsigned char *sha1, char **ref)
1091 {
1092         char *last_branch = substitute_branch_name(&str, &len);
1093         const char **p, *r;
1094         int refs_found = 0;
1095
1096         *ref = NULL;
1097         for (p = ref_rev_parse_rules; *p; p++) {
1098                 char fullref[PATH_MAX];
1099                 unsigned char sha1_from_ref[20];
1100                 unsigned char *this_result;
1101                 int flag;
1102
1103                 this_result = refs_found ? sha1_from_ref : sha1;
1104                 mksnpath(fullref, sizeof(fullref), *p, len, str);
1105                 r = resolve_ref(fullref, this_result, 1, &flag);
1106                 if (r) {
1107                         if (!refs_found++)
1108                                 *ref = xstrdup(r);
1109                         if (!warn_ambiguous_refs)
1110                                 break;
1111                 } else if ((flag & REF_ISSYMREF) && strcmp(fullref, "HEAD")) {
1112                         warning("ignoring dangling symref %s.", fullref);
1113                 } else if ((flag & REF_ISBROKEN) && strchr(fullref, '/')) {
1114                         warning("ignoring broken ref %s.", fullref);
1115                 }
1116         }
1117         free(last_branch);
1118         return refs_found;
1119 }
1120
1121 int dwim_log(const char *str, int len, unsigned char *sha1, char **log)
1122 {
1123         char *last_branch = substitute_branch_name(&str, &len);
1124         const char **p;
1125         int logs_found = 0;
1126
1127         *log = NULL;
1128         for (p = ref_rev_parse_rules; *p; p++) {
1129                 struct stat st;
1130                 unsigned char hash[20];
1131                 char path[PATH_MAX];
1132                 const char *ref, *it;
1133
1134                 mksnpath(path, sizeof(path), *p, len, str);
1135                 ref = resolve_ref(path, hash, 1, NULL);
1136                 if (!ref)
1137                         continue;
1138                 if (!stat(git_path("logs/%s", path), &st) &&
1139                     S_ISREG(st.st_mode))
1140                         it = path;
1141                 else if (strcmp(ref, path) &&
1142                          !stat(git_path("logs/%s", ref), &st) &&
1143                          S_ISREG(st.st_mode))
1144                         it = ref;
1145                 else
1146                         continue;
1147                 if (!logs_found++) {
1148                         *log = xstrdup(it);
1149                         hashcpy(sha1, hash);
1150                 }
1151                 if (!warn_ambiguous_refs)
1152                         break;
1153         }
1154         free(last_branch);
1155         return logs_found;
1156 }
1157
1158 static struct ref_lock *lock_ref_sha1_basic(const char *ref, const unsigned char *old_sha1, int flags, int *type_p)
1159 {
1160         char *ref_file;
1161         const char *orig_ref = ref;
1162         struct ref_lock *lock;
1163         int last_errno = 0;
1164         int type, lflags;
1165         int mustexist = (old_sha1 && !is_null_sha1(old_sha1));
1166         int missing = 0;
1167
1168         lock = xcalloc(1, sizeof(struct ref_lock));
1169         lock->lock_fd = -1;
1170
1171         ref = resolve_ref(ref, lock->old_sha1, mustexist, &type);
1172         if (!ref && errno == EISDIR) {
1173                 /* we are trying to lock foo but we used to
1174                  * have foo/bar which now does not exist;
1175                  * it is normal for the empty directory 'foo'
1176                  * to remain.
1177                  */
1178                 ref_file = git_path("%s", orig_ref);
1179                 if (remove_empty_directories(ref_file)) {
1180                         last_errno = errno;
1181                         error("there are still refs under '%s'", orig_ref);
1182                         goto error_return;
1183                 }
1184                 ref = resolve_ref(orig_ref, lock->old_sha1, mustexist, &type);
1185         }
1186         if (type_p)
1187             *type_p = type;
1188         if (!ref) {
1189                 last_errno = errno;
1190                 error("unable to resolve reference %s: %s",
1191                         orig_ref, strerror(errno));
1192                 goto error_return;
1193         }
1194         missing = is_null_sha1(lock->old_sha1);
1195         /* When the ref did not exist and we are creating it,
1196          * make sure there is no existing ref that is packed
1197          * whose name begins with our refname, nor a ref whose
1198          * name is a proper prefix of our refname.
1199          */
1200         if (missing &&
1201              !is_refname_available(ref, NULL, get_packed_refs(NULL), 0)) {
1202                 last_errno = ENOTDIR;
1203                 goto error_return;
1204         }
1205
1206         lock->lk = xcalloc(1, sizeof(struct lock_file));
1207
1208         lflags = LOCK_DIE_ON_ERROR;
1209         if (flags & REF_NODEREF) {
1210                 ref = orig_ref;
1211                 lflags |= LOCK_NODEREF;
1212         }
1213         lock->ref_name = xstrdup(ref);
1214         lock->orig_ref_name = xstrdup(orig_ref);
1215         ref_file = git_path("%s", ref);
1216         if (missing)
1217                 lock->force_write = 1;
1218         if ((flags & REF_NODEREF) && (type & REF_ISSYMREF))
1219                 lock->force_write = 1;
1220
1221         if (safe_create_leading_directories(ref_file)) {
1222                 last_errno = errno;
1223                 error("unable to create directory for %s", ref_file);
1224                 goto error_return;
1225         }
1226
1227         lock->lock_fd = hold_lock_file_for_update(lock->lk, ref_file, lflags);
1228         return old_sha1 ? verify_lock(lock, old_sha1, mustexist) : lock;
1229
1230  error_return:
1231         unlock_ref(lock);
1232         errno = last_errno;
1233         return NULL;
1234 }
1235
1236 struct ref_lock *lock_ref_sha1(const char *ref, const unsigned char *old_sha1)
1237 {
1238         char refpath[PATH_MAX];
1239         if (check_refname_format(ref, 0))
1240                 return NULL;
1241         strcpy(refpath, mkpath("refs/%s", ref));
1242         return lock_ref_sha1_basic(refpath, old_sha1, 0, NULL);
1243 }
1244
1245 struct ref_lock *lock_any_ref_for_update(const char *ref, const unsigned char *old_sha1, int flags)
1246 {
1247         if (check_refname_format(ref, REFNAME_ALLOW_ONELEVEL))
1248                 return NULL;
1249         return lock_ref_sha1_basic(ref, old_sha1, flags, NULL);
1250 }
1251
1252 static struct lock_file packlock;
1253
1254 static int repack_without_ref(const char *refname)
1255 {
1256         struct ref_list *list, *packed_ref_list;
1257         int fd;
1258         int found = 0;
1259
1260         packed_ref_list = get_packed_refs(NULL);
1261         for (list = packed_ref_list; list; list = list->next) {
1262                 if (!strcmp(refname, list->name)) {
1263                         found = 1;
1264                         break;
1265                 }
1266         }
1267         if (!found)
1268                 return 0;
1269         fd = hold_lock_file_for_update(&packlock, git_path("packed-refs"), 0);
1270         if (fd < 0) {
1271                 unable_to_lock_error(git_path("packed-refs"), errno);
1272                 return error("cannot delete '%s' from packed refs", refname);
1273         }
1274
1275         for (list = packed_ref_list; list; list = list->next) {
1276                 char line[PATH_MAX + 100];
1277                 int len;
1278
1279                 if (!strcmp(refname, list->name))
1280                         continue;
1281                 len = snprintf(line, sizeof(line), "%s %s\n",
1282                                sha1_to_hex(list->sha1), list->name);
1283                 /* this should not happen but just being defensive */
1284                 if (len > sizeof(line))
1285                         die("too long a refname '%s'", list->name);
1286                 write_or_die(fd, line, len);
1287         }
1288         return commit_lock_file(&packlock);
1289 }
1290
1291 int delete_ref(const char *refname, const unsigned char *sha1, int delopt)
1292 {
1293         struct ref_lock *lock;
1294         int err, i = 0, ret = 0, flag = 0;
1295
1296         lock = lock_ref_sha1_basic(refname, sha1, 0, &flag);
1297         if (!lock)
1298                 return 1;
1299         if (!(flag & REF_ISPACKED) || flag & REF_ISSYMREF) {
1300                 /* loose */
1301                 const char *path;
1302
1303                 if (!(delopt & REF_NODEREF)) {
1304                         i = strlen(lock->lk->filename) - 5; /* .lock */
1305                         lock->lk->filename[i] = 0;
1306                         path = lock->lk->filename;
1307                 } else {
1308                         path = git_path("%s", refname);
1309                 }
1310                 err = unlink_or_warn(path);
1311                 if (err && errno != ENOENT)
1312                         ret = 1;
1313
1314                 if (!(delopt & REF_NODEREF))
1315                         lock->lk->filename[i] = '.';
1316         }
1317         /* removing the loose one could have resurrected an earlier
1318          * packed one.  Also, if it was not loose we need to repack
1319          * without it.
1320          */
1321         ret |= repack_without_ref(refname);
1322
1323         unlink_or_warn(git_path("logs/%s", lock->ref_name));
1324         invalidate_cached_refs();
1325         unlock_ref(lock);
1326         return ret;
1327 }
1328
1329 /*
1330  * People using contrib's git-new-workdir have .git/logs/refs ->
1331  * /some/other/path/.git/logs/refs, and that may live on another device.
1332  *
1333  * IOW, to avoid cross device rename errors, the temporary renamed log must
1334  * live into logs/refs.
1335  */
1336 #define TMP_RENAMED_LOG  "logs/refs/.tmp-renamed-log"
1337
1338 int rename_ref(const char *oldref, const char *newref, const char *logmsg)
1339 {
1340         static const char renamed_ref[] = "RENAMED-REF";
1341         unsigned char sha1[20], orig_sha1[20];
1342         int flag = 0, logmoved = 0;
1343         struct ref_lock *lock;
1344         struct stat loginfo;
1345         int log = !lstat(git_path("logs/%s", oldref), &loginfo);
1346         const char *symref = NULL;
1347
1348         if (log && S_ISLNK(loginfo.st_mode))
1349                 return error("reflog for %s is a symlink", oldref);
1350
1351         symref = resolve_ref(oldref, orig_sha1, 1, &flag);
1352         if (flag & REF_ISSYMREF)
1353                 return error("refname %s is a symbolic ref, renaming it is not supported",
1354                         oldref);
1355         if (!symref)
1356                 return error("refname %s not found", oldref);
1357
1358         if (!is_refname_available(newref, oldref, get_packed_refs(NULL), 0))
1359                 return 1;
1360
1361         if (!is_refname_available(newref, oldref, get_loose_refs(NULL), 0))
1362                 return 1;
1363
1364         lock = lock_ref_sha1_basic(renamed_ref, NULL, 0, NULL);
1365         if (!lock)
1366                 return error("unable to lock %s", renamed_ref);
1367         lock->force_write = 1;
1368         if (write_ref_sha1(lock, orig_sha1, logmsg))
1369                 return error("unable to save current sha1 in %s", renamed_ref);
1370
1371         if (log && rename(git_path("logs/%s", oldref), git_path(TMP_RENAMED_LOG)))
1372                 return error("unable to move logfile logs/%s to "TMP_RENAMED_LOG": %s",
1373                         oldref, strerror(errno));
1374
1375         if (delete_ref(oldref, orig_sha1, REF_NODEREF)) {
1376                 error("unable to delete old %s", oldref);
1377                 goto rollback;
1378         }
1379
1380         if (resolve_ref(newref, sha1, 1, &flag) && delete_ref(newref, sha1, REF_NODEREF)) {
1381                 if (errno==EISDIR) {
1382                         if (remove_empty_directories(git_path("%s", newref))) {
1383                                 error("Directory not empty: %s", newref);
1384                                 goto rollback;
1385                         }
1386                 } else {
1387                         error("unable to delete existing %s", newref);
1388                         goto rollback;
1389                 }
1390         }
1391
1392         if (log && safe_create_leading_directories(git_path("logs/%s", newref))) {
1393                 error("unable to create directory for %s", newref);
1394                 goto rollback;
1395         }
1396
1397  retry:
1398         if (log && rename(git_path(TMP_RENAMED_LOG), git_path("logs/%s", newref))) {
1399                 if (errno==EISDIR || errno==ENOTDIR) {
1400                         /*
1401                          * rename(a, b) when b is an existing
1402                          * directory ought to result in ISDIR, but
1403                          * Solaris 5.8 gives ENOTDIR.  Sheesh.
1404                          */
1405                         if (remove_empty_directories(git_path("logs/%s", newref))) {
1406                                 error("Directory not empty: logs/%s", newref);
1407                                 goto rollback;
1408                         }
1409                         goto retry;
1410                 } else {
1411                         error("unable to move logfile "TMP_RENAMED_LOG" to logs/%s: %s",
1412                                 newref, strerror(errno));
1413                         goto rollback;
1414                 }
1415         }
1416         logmoved = log;
1417
1418         lock = lock_ref_sha1_basic(newref, NULL, 0, NULL);
1419         if (!lock) {
1420                 error("unable to lock %s for update", newref);
1421                 goto rollback;
1422         }
1423         lock->force_write = 1;
1424         hashcpy(lock->old_sha1, orig_sha1);
1425         if (write_ref_sha1(lock, orig_sha1, logmsg)) {
1426                 error("unable to write current sha1 into %s", newref);
1427                 goto rollback;
1428         }
1429
1430         return 0;
1431
1432  rollback:
1433         lock = lock_ref_sha1_basic(oldref, NULL, 0, NULL);
1434         if (!lock) {
1435                 error("unable to lock %s for rollback", oldref);
1436                 goto rollbacklog;
1437         }
1438
1439         lock->force_write = 1;
1440         flag = log_all_ref_updates;
1441         log_all_ref_updates = 0;
1442         if (write_ref_sha1(lock, orig_sha1, NULL))
1443                 error("unable to write current sha1 into %s", oldref);
1444         log_all_ref_updates = flag;
1445
1446  rollbacklog:
1447         if (logmoved && rename(git_path("logs/%s", newref), git_path("logs/%s", oldref)))
1448                 error("unable to restore logfile %s from %s: %s",
1449                         oldref, newref, strerror(errno));
1450         if (!logmoved && log &&
1451             rename(git_path(TMP_RENAMED_LOG), git_path("logs/%s", oldref)))
1452                 error("unable to restore logfile %s from "TMP_RENAMED_LOG": %s",
1453                         oldref, strerror(errno));
1454
1455         return 1;
1456 }
1457
1458 int close_ref(struct ref_lock *lock)
1459 {
1460         if (close_lock_file(lock->lk))
1461                 return -1;
1462         lock->lock_fd = -1;
1463         return 0;
1464 }
1465
1466 int commit_ref(struct ref_lock *lock)
1467 {
1468         if (commit_lock_file(lock->lk))
1469                 return -1;
1470         lock->lock_fd = -1;
1471         return 0;
1472 }
1473
1474 void unlock_ref(struct ref_lock *lock)
1475 {
1476         /* Do not free lock->lk -- atexit() still looks at them */
1477         if (lock->lk)
1478                 rollback_lock_file(lock->lk);
1479         free(lock->ref_name);
1480         free(lock->orig_ref_name);
1481         free(lock);
1482 }
1483
1484 /*
1485  * copy the reflog message msg to buf, which has been allocated sufficiently
1486  * large, while cleaning up the whitespaces.  Especially, convert LF to space,
1487  * because reflog file is one line per entry.
1488  */
1489 static int copy_msg(char *buf, const char *msg)
1490 {
1491         char *cp = buf;
1492         char c;
1493         int wasspace = 1;
1494
1495         *cp++ = '\t';
1496         while ((c = *msg++)) {
1497                 if (wasspace && isspace(c))
1498                         continue;
1499                 wasspace = isspace(c);
1500                 if (wasspace)
1501                         c = ' ';
1502                 *cp++ = c;
1503         }
1504         while (buf < cp && isspace(cp[-1]))
1505                 cp--;
1506         *cp++ = '\n';
1507         return cp - buf;
1508 }
1509
1510 int log_ref_setup(const char *ref_name, char *logfile, int bufsize)
1511 {
1512         int logfd, oflags = O_APPEND | O_WRONLY;
1513
1514         git_snpath(logfile, bufsize, "logs/%s", ref_name);
1515         if (log_all_ref_updates &&
1516             (!prefixcmp(ref_name, "refs/heads/") ||
1517              !prefixcmp(ref_name, "refs/remotes/") ||
1518              !prefixcmp(ref_name, "refs/notes/") ||
1519              !strcmp(ref_name, "HEAD"))) {
1520                 if (safe_create_leading_directories(logfile) < 0)
1521                         return error("unable to create directory for %s",
1522                                      logfile);
1523                 oflags |= O_CREAT;
1524         }
1525
1526         logfd = open(logfile, oflags, 0666);
1527         if (logfd < 0) {
1528                 if (!(oflags & O_CREAT) && errno == ENOENT)
1529                         return 0;
1530
1531                 if ((oflags & O_CREAT) && errno == EISDIR) {
1532                         if (remove_empty_directories(logfile)) {
1533                                 return error("There are still logs under '%s'",
1534                                              logfile);
1535                         }
1536                         logfd = open(logfile, oflags, 0666);
1537                 }
1538
1539                 if (logfd < 0)
1540                         return error("Unable to append to %s: %s",
1541                                      logfile, strerror(errno));
1542         }
1543
1544         adjust_shared_perm(logfile);
1545         close(logfd);
1546         return 0;
1547 }
1548
1549 static int log_ref_write(const char *ref_name, const unsigned char *old_sha1,
1550                          const unsigned char *new_sha1, const char *msg)
1551 {
1552         int logfd, result, written, oflags = O_APPEND | O_WRONLY;
1553         unsigned maxlen, len;
1554         int msglen;
1555         char log_file[PATH_MAX];
1556         char *logrec;
1557         const char *committer;
1558
1559         if (log_all_ref_updates < 0)
1560                 log_all_ref_updates = !is_bare_repository();
1561
1562         result = log_ref_setup(ref_name, log_file, sizeof(log_file));
1563         if (result)
1564                 return result;
1565
1566         logfd = open(log_file, oflags);
1567         if (logfd < 0)
1568                 return 0;
1569         msglen = msg ? strlen(msg) : 0;
1570         committer = git_committer_info(0);
1571         maxlen = strlen(committer) + msglen + 100;
1572         logrec = xmalloc(maxlen);
1573         len = sprintf(logrec, "%s %s %s\n",
1574                       sha1_to_hex(old_sha1),
1575                       sha1_to_hex(new_sha1),
1576                       committer);
1577         if (msglen)
1578                 len += copy_msg(logrec + len - 1, msg) - 1;
1579         written = len <= maxlen ? write_in_full(logfd, logrec, len) : -1;
1580         free(logrec);
1581         if (close(logfd) != 0 || written != len)
1582                 return error("Unable to append to %s", log_file);
1583         return 0;
1584 }
1585
1586 static int is_branch(const char *refname)
1587 {
1588         return !strcmp(refname, "HEAD") || !prefixcmp(refname, "refs/heads/");
1589 }
1590
1591 int write_ref_sha1(struct ref_lock *lock,
1592         const unsigned char *sha1, const char *logmsg)
1593 {
1594         static char term = '\n';
1595         struct object *o;
1596
1597         if (!lock)
1598                 return -1;
1599         if (!lock->force_write && !hashcmp(lock->old_sha1, sha1)) {
1600                 unlock_ref(lock);
1601                 return 0;
1602         }
1603         o = parse_object(sha1);
1604         if (!o) {
1605                 error("Trying to write ref %s with nonexistent object %s",
1606                         lock->ref_name, sha1_to_hex(sha1));
1607                 unlock_ref(lock);
1608                 return -1;
1609         }
1610         if (o->type != OBJ_COMMIT && is_branch(lock->ref_name)) {
1611                 error("Trying to write non-commit object %s to branch %s",
1612                         sha1_to_hex(sha1), lock->ref_name);
1613                 unlock_ref(lock);
1614                 return -1;
1615         }
1616         if (write_in_full(lock->lock_fd, sha1_to_hex(sha1), 40) != 40 ||
1617             write_in_full(lock->lock_fd, &term, 1) != 1
1618                 || close_ref(lock) < 0) {
1619                 error("Couldn't write %s", lock->lk->filename);
1620                 unlock_ref(lock);
1621                 return -1;
1622         }
1623         invalidate_cached_refs();
1624         if (log_ref_write(lock->ref_name, lock->old_sha1, sha1, logmsg) < 0 ||
1625             (strcmp(lock->ref_name, lock->orig_ref_name) &&
1626              log_ref_write(lock->orig_ref_name, lock->old_sha1, sha1, logmsg) < 0)) {
1627                 unlock_ref(lock);
1628                 return -1;
1629         }
1630         if (strcmp(lock->orig_ref_name, "HEAD") != 0) {
1631                 /*
1632                  * Special hack: If a branch is updated directly and HEAD
1633                  * points to it (may happen on the remote side of a push
1634                  * for example) then logically the HEAD reflog should be
1635                  * updated too.
1636                  * A generic solution implies reverse symref information,
1637                  * but finding all symrefs pointing to the given branch
1638                  * would be rather costly for this rare event (the direct
1639                  * update of a branch) to be worth it.  So let's cheat and
1640                  * check with HEAD only which should cover 99% of all usage
1641                  * scenarios (even 100% of the default ones).
1642                  */
1643                 unsigned char head_sha1[20];
1644                 int head_flag;
1645                 const char *head_ref;
1646                 head_ref = resolve_ref("HEAD", head_sha1, 1, &head_flag);
1647                 if (head_ref && (head_flag & REF_ISSYMREF) &&
1648                     !strcmp(head_ref, lock->ref_name))
1649                         log_ref_write("HEAD", lock->old_sha1, sha1, logmsg);
1650         }
1651         if (commit_ref(lock)) {
1652                 error("Couldn't set %s", lock->ref_name);
1653                 unlock_ref(lock);
1654                 return -1;
1655         }
1656         unlock_ref(lock);
1657         return 0;
1658 }
1659
1660 int create_symref(const char *ref_target, const char *refs_heads_master,
1661                   const char *logmsg)
1662 {
1663         const char *lockpath;
1664         char ref[1000];
1665         int fd, len, written;
1666         char *git_HEAD = git_pathdup("%s", ref_target);
1667         unsigned char old_sha1[20], new_sha1[20];
1668
1669         if (logmsg && read_ref(ref_target, old_sha1))
1670                 hashclr(old_sha1);
1671
1672         if (safe_create_leading_directories(git_HEAD) < 0)
1673                 return error("unable to create directory for %s", git_HEAD);
1674
1675 #ifndef NO_SYMLINK_HEAD
1676         if (prefer_symlink_refs) {
1677                 unlink(git_HEAD);
1678                 if (!symlink(refs_heads_master, git_HEAD))
1679                         goto done;
1680                 fprintf(stderr, "no symlink - falling back to symbolic ref\n");
1681         }
1682 #endif
1683
1684         len = snprintf(ref, sizeof(ref), "ref: %s\n", refs_heads_master);
1685         if (sizeof(ref) <= len) {
1686                 error("refname too long: %s", refs_heads_master);
1687                 goto error_free_return;
1688         }
1689         lockpath = mkpath("%s.lock", git_HEAD);
1690         fd = open(lockpath, O_CREAT | O_EXCL | O_WRONLY, 0666);
1691         if (fd < 0) {
1692                 error("Unable to open %s for writing", lockpath);
1693                 goto error_free_return;
1694         }
1695         written = write_in_full(fd, ref, len);
1696         if (close(fd) != 0 || written != len) {
1697                 error("Unable to write to %s", lockpath);
1698                 goto error_unlink_return;
1699         }
1700         if (rename(lockpath, git_HEAD) < 0) {
1701                 error("Unable to create %s", git_HEAD);
1702                 goto error_unlink_return;
1703         }
1704         if (adjust_shared_perm(git_HEAD)) {
1705                 error("Unable to fix permissions on %s", lockpath);
1706         error_unlink_return:
1707                 unlink_or_warn(lockpath);
1708         error_free_return:
1709                 free(git_HEAD);
1710                 return -1;
1711         }
1712
1713 #ifndef NO_SYMLINK_HEAD
1714         done:
1715 #endif
1716         if (logmsg && !read_ref(refs_heads_master, new_sha1))
1717                 log_ref_write(ref_target, old_sha1, new_sha1, logmsg);
1718
1719         free(git_HEAD);
1720         return 0;
1721 }
1722
1723 static char *ref_msg(const char *line, const char *endp)
1724 {
1725         const char *ep;
1726         line += 82;
1727         ep = memchr(line, '\n', endp - line);
1728         if (!ep)
1729                 ep = endp;
1730         return xmemdupz(line, ep - line);
1731 }
1732
1733 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)
1734 {
1735         const char *logfile, *logdata, *logend, *rec, *lastgt, *lastrec;
1736         char *tz_c;
1737         int logfd, tz, reccnt = 0;
1738         struct stat st;
1739         unsigned long date;
1740         unsigned char logged_sha1[20];
1741         void *log_mapped;
1742         size_t mapsz;
1743
1744         logfile = git_path("logs/%s", ref);
1745         logfd = open(logfile, O_RDONLY, 0);
1746         if (logfd < 0)
1747                 die_errno("Unable to read log '%s'", logfile);
1748         fstat(logfd, &st);
1749         if (!st.st_size)
1750                 die("Log %s is empty.", logfile);
1751         mapsz = xsize_t(st.st_size);
1752         log_mapped = xmmap(NULL, mapsz, PROT_READ, MAP_PRIVATE, logfd, 0);
1753         logdata = log_mapped;
1754         close(logfd);
1755
1756         lastrec = NULL;
1757         rec = logend = logdata + st.st_size;
1758         while (logdata < rec) {
1759                 reccnt++;
1760                 if (logdata < rec && *(rec-1) == '\n')
1761                         rec--;
1762                 lastgt = NULL;
1763                 while (logdata < rec && *(rec-1) != '\n') {
1764                         rec--;
1765                         if (*rec == '>')
1766                                 lastgt = rec;
1767                 }
1768                 if (!lastgt)
1769                         die("Log %s is corrupt.", logfile);
1770                 date = strtoul(lastgt + 1, &tz_c, 10);
1771                 if (date <= at_time || cnt == 0) {
1772                         tz = strtoul(tz_c, NULL, 10);
1773                         if (msg)
1774                                 *msg = ref_msg(rec, logend);
1775                         if (cutoff_time)
1776                                 *cutoff_time = date;
1777                         if (cutoff_tz)
1778                                 *cutoff_tz = tz;
1779                         if (cutoff_cnt)
1780                                 *cutoff_cnt = reccnt - 1;
1781                         if (lastrec) {
1782                                 if (get_sha1_hex(lastrec, logged_sha1))
1783                                         die("Log %s is corrupt.", logfile);
1784                                 if (get_sha1_hex(rec + 41, sha1))
1785                                         die("Log %s is corrupt.", logfile);
1786                                 if (hashcmp(logged_sha1, sha1)) {
1787                                         warning("Log %s has gap after %s.",
1788                                                 logfile, show_date(date, tz, DATE_RFC2822));
1789                                 }
1790                         }
1791                         else if (date == at_time) {
1792                                 if (get_sha1_hex(rec + 41, sha1))
1793                                         die("Log %s is corrupt.", logfile);
1794                         }
1795                         else {
1796                                 if (get_sha1_hex(rec + 41, logged_sha1))
1797                                         die("Log %s is corrupt.", logfile);
1798                                 if (hashcmp(logged_sha1, sha1)) {
1799                                         warning("Log %s unexpectedly ended on %s.",
1800                                                 logfile, show_date(date, tz, DATE_RFC2822));
1801                                 }
1802                         }
1803                         munmap(log_mapped, mapsz);
1804                         return 0;
1805                 }
1806                 lastrec = rec;
1807                 if (cnt > 0)
1808                         cnt--;
1809         }
1810
1811         rec = logdata;
1812         while (rec < logend && *rec != '>' && *rec != '\n')
1813                 rec++;
1814         if (rec == logend || *rec == '\n')
1815                 die("Log %s is corrupt.", logfile);
1816         date = strtoul(rec + 1, &tz_c, 10);
1817         tz = strtoul(tz_c, NULL, 10);
1818         if (get_sha1_hex(logdata, sha1))
1819                 die("Log %s is corrupt.", logfile);
1820         if (is_null_sha1(sha1)) {
1821                 if (get_sha1_hex(logdata + 41, sha1))
1822                         die("Log %s is corrupt.", logfile);
1823         }
1824         if (msg)
1825                 *msg = ref_msg(logdata, logend);
1826         munmap(log_mapped, mapsz);
1827
1828         if (cutoff_time)
1829                 *cutoff_time = date;
1830         if (cutoff_tz)
1831                 *cutoff_tz = tz;
1832         if (cutoff_cnt)
1833                 *cutoff_cnt = reccnt;
1834         return 1;
1835 }
1836
1837 int for_each_recent_reflog_ent(const char *ref, each_reflog_ent_fn fn, long ofs, void *cb_data)
1838 {
1839         const char *logfile;
1840         FILE *logfp;
1841         struct strbuf sb = STRBUF_INIT;
1842         int ret = 0;
1843
1844         logfile = git_path("logs/%s", ref);
1845         logfp = fopen(logfile, "r");
1846         if (!logfp)
1847                 return -1;
1848
1849         if (ofs) {
1850                 struct stat statbuf;
1851                 if (fstat(fileno(logfp), &statbuf) ||
1852                     statbuf.st_size < ofs ||
1853                     fseek(logfp, -ofs, SEEK_END) ||
1854                     strbuf_getwholeline(&sb, logfp, '\n')) {
1855                         fclose(logfp);
1856                         strbuf_release(&sb);
1857                         return -1;
1858                 }
1859         }
1860
1861         while (!strbuf_getwholeline(&sb, logfp, '\n')) {
1862                 unsigned char osha1[20], nsha1[20];
1863                 char *email_end, *message;
1864                 unsigned long timestamp;
1865                 int tz;
1866
1867                 /* old SP new SP name <email> SP time TAB msg LF */
1868                 if (sb.len < 83 || sb.buf[sb.len - 1] != '\n' ||
1869                     get_sha1_hex(sb.buf, osha1) || sb.buf[40] != ' ' ||
1870                     get_sha1_hex(sb.buf + 41, nsha1) || sb.buf[81] != ' ' ||
1871                     !(email_end = strchr(sb.buf + 82, '>')) ||
1872                     email_end[1] != ' ' ||
1873                     !(timestamp = strtoul(email_end + 2, &message, 10)) ||
1874                     !message || message[0] != ' ' ||
1875                     (message[1] != '+' && message[1] != '-') ||
1876                     !isdigit(message[2]) || !isdigit(message[3]) ||
1877                     !isdigit(message[4]) || !isdigit(message[5]))
1878                         continue; /* corrupt? */
1879                 email_end[1] = '\0';
1880                 tz = strtol(message + 1, NULL, 10);
1881                 if (message[6] != '\t')
1882                         message += 6;
1883                 else
1884                         message += 7;
1885                 ret = fn(osha1, nsha1, sb.buf + 82, timestamp, tz, message,
1886                          cb_data);
1887                 if (ret)
1888                         break;
1889         }
1890         fclose(logfp);
1891         strbuf_release(&sb);
1892         return ret;
1893 }
1894
1895 int for_each_reflog_ent(const char *ref, each_reflog_ent_fn fn, void *cb_data)
1896 {
1897         return for_each_recent_reflog_ent(ref, fn, 0, cb_data);
1898 }
1899
1900 static int do_for_each_reflog(const char *base, each_ref_fn fn, void *cb_data)
1901 {
1902         DIR *dir = opendir(git_path("logs/%s", base));
1903         int retval = 0;
1904
1905         if (dir) {
1906                 struct dirent *de;
1907                 int baselen = strlen(base);
1908                 char *log = xmalloc(baselen + 257);
1909
1910                 memcpy(log, base, baselen);
1911                 if (baselen && base[baselen-1] != '/')
1912                         log[baselen++] = '/';
1913
1914                 while ((de = readdir(dir)) != NULL) {
1915                         struct stat st;
1916                         int namelen;
1917
1918                         if (de->d_name[0] == '.')
1919                                 continue;
1920                         namelen = strlen(de->d_name);
1921                         if (namelen > 255)
1922                                 continue;
1923                         if (has_extension(de->d_name, ".lock"))
1924                                 continue;
1925                         memcpy(log + baselen, de->d_name, namelen+1);
1926                         if (stat(git_path("logs/%s", log), &st) < 0)
1927                                 continue;
1928                         if (S_ISDIR(st.st_mode)) {
1929                                 retval = do_for_each_reflog(log, fn, cb_data);
1930                         } else {
1931                                 unsigned char sha1[20];
1932                                 if (!resolve_ref(log, sha1, 0, NULL))
1933                                         retval = error("bad ref for %s", log);
1934                                 else
1935                                         retval = fn(log, sha1, 0, cb_data);
1936                         }
1937                         if (retval)
1938                                 break;
1939                 }
1940                 free(log);
1941                 closedir(dir);
1942         }
1943         else if (*base)
1944                 return errno;
1945         return retval;
1946 }
1947
1948 int for_each_reflog(each_ref_fn fn, void *cb_data)
1949 {
1950         return do_for_each_reflog("", fn, cb_data);
1951 }
1952
1953 int update_ref(const char *action, const char *refname,
1954                 const unsigned char *sha1, const unsigned char *oldval,
1955                 int flags, enum action_on_err onerr)
1956 {
1957         static struct ref_lock *lock;
1958         lock = lock_any_ref_for_update(refname, oldval, flags);
1959         if (!lock) {
1960                 const char *str = "Cannot lock the ref '%s'.";
1961                 switch (onerr) {
1962                 case MSG_ON_ERR: error(str, refname); break;
1963                 case DIE_ON_ERR: die(str, refname); break;
1964                 case QUIET_ON_ERR: break;
1965                 }
1966                 return 1;
1967         }
1968         if (write_ref_sha1(lock, sha1, action) < 0) {
1969                 const char *str = "Cannot update the ref '%s'.";
1970                 switch (onerr) {
1971                 case MSG_ON_ERR: error(str, refname); break;
1972                 case DIE_ON_ERR: die(str, refname); break;
1973                 case QUIET_ON_ERR: break;
1974                 }
1975                 return 1;
1976         }
1977         return 0;
1978 }
1979
1980 int ref_exists(char *refname)
1981 {
1982         unsigned char sha1[20];
1983         return !!resolve_ref(refname, sha1, 1, NULL);
1984 }
1985
1986 struct ref *find_ref_by_name(const struct ref *list, const char *name)
1987 {
1988         for ( ; list; list = list->next)
1989                 if (!strcmp(list->name, name))
1990                         return (struct ref *)list;
1991         return NULL;
1992 }
1993
1994 /*
1995  * generate a format suitable for scanf from a ref_rev_parse_rules
1996  * rule, that is replace the "%.*s" spec with a "%s" spec
1997  */
1998 static void gen_scanf_fmt(char *scanf_fmt, const char *rule)
1999 {
2000         char *spec;
2001
2002         spec = strstr(rule, "%.*s");
2003         if (!spec || strstr(spec + 4, "%.*s"))
2004                 die("invalid rule in ref_rev_parse_rules: %s", rule);
2005
2006         /* copy all until spec */
2007         strncpy(scanf_fmt, rule, spec - rule);
2008         scanf_fmt[spec - rule] = '\0';
2009         /* copy new spec */
2010         strcat(scanf_fmt, "%s");
2011         /* copy remaining rule */
2012         strcat(scanf_fmt, spec + 4);
2013
2014         return;
2015 }
2016
2017 char *shorten_unambiguous_ref(const char *ref, int strict)
2018 {
2019         int i;
2020         static char **scanf_fmts;
2021         static int nr_rules;
2022         char *short_name;
2023
2024         /* pre generate scanf formats from ref_rev_parse_rules[] */
2025         if (!nr_rules) {
2026                 size_t total_len = 0;
2027
2028                 /* the rule list is NULL terminated, count them first */
2029                 for (; ref_rev_parse_rules[nr_rules]; nr_rules++)
2030                         /* no +1 because strlen("%s") < strlen("%.*s") */
2031                         total_len += strlen(ref_rev_parse_rules[nr_rules]);
2032
2033                 scanf_fmts = xmalloc(nr_rules * sizeof(char *) + total_len);
2034
2035                 total_len = 0;
2036                 for (i = 0; i < nr_rules; i++) {
2037                         scanf_fmts[i] = (char *)&scanf_fmts[nr_rules]
2038                                         + total_len;
2039                         gen_scanf_fmt(scanf_fmts[i], ref_rev_parse_rules[i]);
2040                         total_len += strlen(ref_rev_parse_rules[i]);
2041                 }
2042         }
2043
2044         /* bail out if there are no rules */
2045         if (!nr_rules)
2046                 return xstrdup(ref);
2047
2048         /* buffer for scanf result, at most ref must fit */
2049         short_name = xstrdup(ref);
2050
2051         /* skip first rule, it will always match */
2052         for (i = nr_rules - 1; i > 0 ; --i) {
2053                 int j;
2054                 int rules_to_fail = i;
2055                 int short_name_len;
2056
2057                 if (1 != sscanf(ref, scanf_fmts[i], short_name))
2058                         continue;
2059
2060                 short_name_len = strlen(short_name);
2061
2062                 /*
2063                  * in strict mode, all (except the matched one) rules
2064                  * must fail to resolve to a valid non-ambiguous ref
2065                  */
2066                 if (strict)
2067                         rules_to_fail = nr_rules;
2068
2069                 /*
2070                  * check if the short name resolves to a valid ref,
2071                  * but use only rules prior to the matched one
2072                  */
2073                 for (j = 0; j < rules_to_fail; j++) {
2074                         const char *rule = ref_rev_parse_rules[j];
2075                         unsigned char short_objectname[20];
2076                         char refname[PATH_MAX];
2077
2078                         /* skip matched rule */
2079                         if (i == j)
2080                                 continue;
2081
2082                         /*
2083                          * the short name is ambiguous, if it resolves
2084                          * (with this previous rule) to a valid ref
2085                          * read_ref() returns 0 on success
2086                          */
2087                         mksnpath(refname, sizeof(refname),
2088                                  rule, short_name_len, short_name);
2089                         if (!read_ref(refname, short_objectname))
2090                                 break;
2091                 }
2092
2093                 /*
2094                  * short name is non-ambiguous if all previous rules
2095                  * haven't resolved to a valid ref
2096                  */
2097                 if (j == rules_to_fail)
2098                         return short_name;
2099         }
2100
2101         free(short_name);
2102         return xstrdup(ref);
2103 }