Merge branch 'jn/no-g-plus-s-on-bsd'
[git] / refs.c
1 #include "cache.h"
2 #include "refs.h"
3 #include "object.h"
4 #include "tag.h"
5 #include "dir.h"
6
7 /* ISSYMREF=01 and ISPACKED=02 are public interfaces */
8 #define REF_KNOWS_PEELED 04
9 #define REF_BROKEN 010
10
11 struct ref_entry {
12         unsigned char flag; /* ISSYMREF? ISPACKED? */
13         unsigned char sha1[20];
14         unsigned char peeled[20];
15         char name[FLEX_ARRAY];
16 };
17
18 struct ref_array {
19         int nr, alloc;
20         struct ref_entry **refs;
21 };
22
23 static const char *parse_ref_line(char *line, unsigned char *sha1)
24 {
25         /*
26          * 42: the answer to everything.
27          *
28          * In this case, it happens to be the answer to
29          *  40 (length of sha1 hex representation)
30          *  +1 (space in between hex and name)
31          *  +1 (newline at the end of the line)
32          */
33         int len = strlen(line) - 42;
34
35         if (len <= 0)
36                 return NULL;
37         if (get_sha1_hex(line, sha1) < 0)
38                 return NULL;
39         if (!isspace(line[40]))
40                 return NULL;
41         line += 41;
42         if (isspace(*line))
43                 return NULL;
44         if (line[len] != '\n')
45                 return NULL;
46         line[len] = 0;
47
48         return line;
49 }
50
51 static void add_ref(const char *name, const unsigned char *sha1,
52                     int flag, struct ref_array *refs,
53                     struct ref_entry **new_entry)
54 {
55         int len;
56         struct ref_entry *entry;
57
58         /* Allocate it and add it in.. */
59         len = strlen(name) + 1;
60         entry = xmalloc(sizeof(struct ref_entry) + len);
61         hashcpy(entry->sha1, sha1);
62         hashclr(entry->peeled);
63         if (check_refname_format(name, REFNAME_ALLOW_ONELEVEL|REFNAME_DOT_COMPONENT))
64                 die("Reference has invalid format: '%s'", name);
65         memcpy(entry->name, name, len);
66         entry->flag = flag;
67         if (new_entry)
68                 *new_entry = entry;
69         ALLOC_GROW(refs->refs, refs->nr + 1, refs->alloc);
70         refs->refs[refs->nr++] = entry;
71 }
72
73 static int ref_entry_cmp(const void *a, const void *b)
74 {
75         struct ref_entry *one = *(struct ref_entry **)a;
76         struct ref_entry *two = *(struct ref_entry **)b;
77         return strcmp(one->name, two->name);
78 }
79
80 static void sort_ref_array(struct ref_array *array)
81 {
82         int i = 0, j = 1;
83
84         /* Nothing to sort unless there are at least two entries */
85         if (array->nr < 2)
86                 return;
87
88         qsort(array->refs, array->nr, sizeof(*array->refs), ref_entry_cmp);
89
90         /* Remove any duplicates from the ref_array */
91         for (; j < array->nr; j++) {
92                 struct ref_entry *a = array->refs[i];
93                 struct ref_entry *b = array->refs[j];
94                 if (!strcmp(a->name, b->name)) {
95                         if (hashcmp(a->sha1, b->sha1))
96                                 die("Duplicated ref, and SHA1s don't match: %s",
97                                     a->name);
98                         warning("Duplicated ref: %s", a->name);
99                         free(b);
100                         continue;
101                 }
102                 i++;
103                 array->refs[i] = array->refs[j];
104         }
105         array->nr = i + 1;
106 }
107
108 static struct ref_entry *search_ref_array(struct ref_array *array, const char *name)
109 {
110         struct ref_entry *e, **r;
111         int len;
112
113         if (name == NULL)
114                 return NULL;
115
116         if (!array->nr)
117                 return NULL;
118
119         len = strlen(name) + 1;
120         e = xmalloc(sizeof(struct ref_entry) + len);
121         memcpy(e->name, name, len);
122
123         r = bsearch(&e, array->refs, array->nr, sizeof(*array->refs), ref_entry_cmp);
124
125         free(e);
126
127         if (r == NULL)
128                 return NULL;
129
130         return *r;
131 }
132
133 /*
134  * Future: need to be in "struct repository"
135  * when doing a full libification.
136  */
137 static struct cached_refs {
138         struct cached_refs *next;
139         char did_loose;
140         char did_packed;
141         struct ref_array loose;
142         struct ref_array packed;
143         /* The submodule name, or "" for the main repo. */
144         char name[FLEX_ARRAY];
145 } *cached_refs;
146
147 static struct ref_entry *current_ref;
148
149 static struct ref_array extra_refs;
150
151 static void free_ref_array(struct ref_array *array)
152 {
153         int i;
154         for (i = 0; i < array->nr; i++)
155                 free(array->refs[i]);
156         free(array->refs);
157         array->nr = array->alloc = 0;
158         array->refs = NULL;
159 }
160
161 static void clear_cached_refs(struct cached_refs *ca)
162 {
163         if (ca->did_loose)
164                 free_ref_array(&ca->loose);
165         if (ca->did_packed)
166                 free_ref_array(&ca->packed);
167         ca->did_loose = ca->did_packed = 0;
168 }
169
170 static struct cached_refs *create_cached_refs(const char *submodule)
171 {
172         int len;
173         struct cached_refs *refs;
174         if (!submodule)
175                 submodule = "";
176         len = strlen(submodule) + 1;
177         refs = xcalloc(1, sizeof(struct cached_refs) + len);
178         memcpy(refs->name, submodule, len);
179         return refs;
180 }
181
182 /*
183  * Return a pointer to a cached_refs for the specified submodule. For
184  * the main repository, use submodule==NULL. The returned structure
185  * will be allocated and initialized but not necessarily populated; it
186  * should not be freed.
187  */
188 static struct cached_refs *get_cached_refs(const char *submodule)
189 {
190         struct cached_refs *refs = cached_refs;
191         if (!submodule)
192                 submodule = "";
193         while (refs) {
194                 if (!strcmp(submodule, refs->name))
195                         return refs;
196                 refs = refs->next;
197         }
198
199         refs = create_cached_refs(submodule);
200         refs->next = cached_refs;
201         cached_refs = refs;
202         return refs;
203 }
204
205 static void invalidate_cached_refs(void)
206 {
207         struct cached_refs *refs = cached_refs;
208         while (refs) {
209                 clear_cached_refs(refs);
210                 refs = refs->next;
211         }
212 }
213
214 static void read_packed_refs(FILE *f, struct ref_array *array)
215 {
216         struct ref_entry *last = NULL;
217         char refline[PATH_MAX];
218         int flag = REF_ISPACKED;
219
220         while (fgets(refline, sizeof(refline), f)) {
221                 unsigned char sha1[20];
222                 const char *name;
223                 static const char header[] = "# pack-refs with:";
224
225                 if (!strncmp(refline, header, sizeof(header)-1)) {
226                         const char *traits = refline + sizeof(header) - 1;
227                         if (strstr(traits, " peeled "))
228                                 flag |= REF_KNOWS_PEELED;
229                         /* perhaps other traits later as well */
230                         continue;
231                 }
232
233                 name = parse_ref_line(refline, sha1);
234                 if (name) {
235                         add_ref(name, sha1, flag, array, &last);
236                         continue;
237                 }
238                 if (last &&
239                     refline[0] == '^' &&
240                     strlen(refline) == 42 &&
241                     refline[41] == '\n' &&
242                     !get_sha1_hex(refline + 1, sha1))
243                         hashcpy(last->peeled, sha1);
244         }
245         sort_ref_array(array);
246 }
247
248 void add_extra_ref(const char *name, const unsigned char *sha1, int flag)
249 {
250         add_ref(name, sha1, flag, &extra_refs, NULL);
251 }
252
253 void clear_extra_refs(void)
254 {
255         free_ref_array(&extra_refs);
256 }
257
258 static struct ref_array *get_packed_refs(const char *submodule)
259 {
260         struct cached_refs *refs = get_cached_refs(submodule);
261
262         if (!refs->did_packed) {
263                 const char *packed_refs_file;
264                 FILE *f;
265
266                 if (submodule)
267                         packed_refs_file = git_path_submodule(submodule, "packed-refs");
268                 else
269                         packed_refs_file = git_path("packed-refs");
270                 f = fopen(packed_refs_file, "r");
271                 if (f) {
272                         read_packed_refs(f, &refs->packed);
273                         fclose(f);
274                 }
275                 refs->did_packed = 1;
276         }
277         return &refs->packed;
278 }
279
280 static void get_ref_dir(const char *submodule, const char *base,
281                         struct ref_array *array)
282 {
283         DIR *dir;
284         const char *path;
285
286         if (submodule)
287                 path = git_path_submodule(submodule, "%s", base);
288         else
289                 path = git_path("%s", base);
290
291
292         dir = opendir(path);
293
294         if (dir) {
295                 struct dirent *de;
296                 int baselen = strlen(base);
297                 char *ref = xmalloc(baselen + 257);
298
299                 memcpy(ref, base, baselen);
300                 if (baselen && base[baselen-1] != '/')
301                         ref[baselen++] = '/';
302
303                 while ((de = readdir(dir)) != NULL) {
304                         unsigned char sha1[20];
305                         struct stat st;
306                         int flag;
307                         int namelen;
308                         const char *refdir;
309
310                         if (de->d_name[0] == '.')
311                                 continue;
312                         namelen = strlen(de->d_name);
313                         if (namelen > 255)
314                                 continue;
315                         if (has_extension(de->d_name, ".lock"))
316                                 continue;
317                         memcpy(ref + baselen, de->d_name, namelen+1);
318                         refdir = submodule
319                                 ? git_path_submodule(submodule, "%s", ref)
320                                 : git_path("%s", ref);
321                         if (stat(refdir, &st) < 0)
322                                 continue;
323                         if (S_ISDIR(st.st_mode)) {
324                                 get_ref_dir(submodule, ref, array);
325                                 continue;
326                         }
327                         if (submodule) {
328                                 hashclr(sha1);
329                                 flag = 0;
330                                 if (resolve_gitlink_ref(submodule, ref, sha1) < 0) {
331                                         hashclr(sha1);
332                                         flag |= REF_BROKEN;
333                                 }
334                         } else
335                                 if (!resolve_ref(ref, sha1, 1, &flag)) {
336                                         hashclr(sha1);
337                                         flag |= REF_BROKEN;
338                                 }
339                         add_ref(ref, sha1, flag, array, NULL);
340                 }
341                 free(ref);
342                 closedir(dir);
343         }
344 }
345
346 struct warn_if_dangling_data {
347         FILE *fp;
348         const char *refname;
349         const char *msg_fmt;
350 };
351
352 static int warn_if_dangling_symref(const char *refname, const unsigned char *sha1,
353                                    int flags, void *cb_data)
354 {
355         struct warn_if_dangling_data *d = cb_data;
356         const char *resolves_to;
357         unsigned char junk[20];
358
359         if (!(flags & REF_ISSYMREF))
360                 return 0;
361
362         resolves_to = resolve_ref(refname, junk, 0, NULL);
363         if (!resolves_to || strcmp(resolves_to, d->refname))
364                 return 0;
365
366         fprintf(d->fp, d->msg_fmt, refname);
367         return 0;
368 }
369
370 void warn_dangling_symref(FILE *fp, const char *msg_fmt, const char *refname)
371 {
372         struct warn_if_dangling_data data;
373
374         data.fp = fp;
375         data.refname = refname;
376         data.msg_fmt = msg_fmt;
377         for_each_rawref(warn_if_dangling_symref, &data);
378 }
379
380 static struct ref_array *get_loose_refs(const char *submodule)
381 {
382         struct cached_refs *refs = get_cached_refs(submodule);
383
384         if (!refs->did_loose) {
385                 get_ref_dir(submodule, "refs", &refs->loose);
386                 sort_ref_array(&refs->loose);
387                 refs->did_loose = 1;
388         }
389         return &refs->loose;
390 }
391
392 /* We allow "recursive" symbolic refs. Only within reason, though */
393 #define MAXDEPTH 5
394 #define MAXREFLEN (1024)
395
396 static int resolve_gitlink_packed_ref(char *name, int pathlen, const char *refname, unsigned char *result)
397 {
398         int retval = -1;
399         struct ref_entry *ref;
400         struct ref_array *array = get_packed_refs(name);
401
402         ref = search_ref_array(array, refname);
403         if (ref != NULL) {
404                 memcpy(result, ref->sha1, 20);
405                 retval = 0;
406         }
407         return retval;
408 }
409
410 static int resolve_gitlink_ref_recursive(char *name, int pathlen, const char *refname, unsigned char *result, int recursion)
411 {
412         int fd, len = strlen(refname);
413         char buffer[128], *p;
414
415         if (recursion > MAXDEPTH || len > MAXREFLEN)
416                 return -1;
417         memcpy(name + pathlen, refname, len+1);
418         fd = open(name, O_RDONLY);
419         if (fd < 0)
420                 return resolve_gitlink_packed_ref(name, pathlen, refname, result);
421
422         len = read(fd, buffer, sizeof(buffer)-1);
423         close(fd);
424         if (len < 0)
425                 return -1;
426         while (len && isspace(buffer[len-1]))
427                 len--;
428         buffer[len] = 0;
429
430         /* Was it a detached head or an old-fashioned symlink? */
431         if (!get_sha1_hex(buffer, result))
432                 return 0;
433
434         /* Symref? */
435         if (strncmp(buffer, "ref:", 4))
436                 return -1;
437         p = buffer + 4;
438         while (isspace(*p))
439                 p++;
440
441         return resolve_gitlink_ref_recursive(name, pathlen, p, result, recursion+1);
442 }
443
444 int resolve_gitlink_ref(const char *path, const char *refname, unsigned char *result)
445 {
446         int len = strlen(path), retval;
447         char *gitdir;
448         const char *tmp;
449
450         while (len && path[len-1] == '/')
451                 len--;
452         if (!len)
453                 return -1;
454         gitdir = xmalloc(len + MAXREFLEN + 8);
455         memcpy(gitdir, path, len);
456         memcpy(gitdir + len, "/.git", 6);
457         len += 5;
458
459         tmp = read_gitfile(gitdir);
460         if (tmp) {
461                 free(gitdir);
462                 len = strlen(tmp);
463                 gitdir = xmalloc(len + MAXREFLEN + 3);
464                 memcpy(gitdir, tmp, len);
465         }
466         gitdir[len] = '/';
467         gitdir[++len] = '\0';
468         retval = resolve_gitlink_ref_recursive(gitdir, len, refname, result, 0);
469         free(gitdir);
470         return retval;
471 }
472
473 /*
474  * Try to read ref from the packed references.  On success, set sha1
475  * and return 0; otherwise, return -1.
476  */
477 static int get_packed_ref(const char *ref, unsigned char *sha1)
478 {
479         struct ref_array *packed = get_packed_refs(NULL);
480         struct ref_entry *entry = search_ref_array(packed, ref);
481         if (entry) {
482                 hashcpy(sha1, entry->sha1);
483                 return 0;
484         }
485         return -1;
486 }
487
488 const char *resolve_ref(const char *ref, unsigned char *sha1, int reading, int *flag)
489 {
490         int depth = MAXDEPTH;
491         ssize_t len;
492         char buffer[256];
493         static char ref_buffer[256];
494         char path[PATH_MAX];
495
496         if (flag)
497                 *flag = 0;
498
499         if (check_refname_format(ref, REFNAME_ALLOW_ONELEVEL))
500                 return NULL;
501
502         for (;;) {
503                 struct stat st;
504                 char *buf;
505                 int fd;
506
507                 if (--depth < 0)
508                         return NULL;
509
510                 git_snpath(path, sizeof(path), "%s", ref);
511
512                 if (lstat(path, &st) < 0) {
513                         if (errno != ENOENT)
514                                 return NULL;
515                         /*
516                          * The loose reference file does not exist;
517                          * check for a packed reference.
518                          */
519                         if (!get_packed_ref(ref, sha1)) {
520                                 if (flag)
521                                         *flag |= REF_ISPACKED;
522                                 return ref;
523                         }
524                         /* The reference is not a packed reference, either. */
525                         if (reading) {
526                                 return NULL;
527                         } else {
528                                 hashclr(sha1);
529                                 return ref;
530                         }
531                 }
532
533                 /* Follow "normalized" - ie "refs/.." symlinks by hand */
534                 if (S_ISLNK(st.st_mode)) {
535                         len = readlink(path, buffer, sizeof(buffer)-1);
536                         if (len < 0)
537                                 return NULL;
538                         buffer[len] = 0;
539                         if (!prefixcmp(buffer, "refs/") &&
540                                         !check_refname_format(buffer, 0)) {
541                                 strcpy(ref_buffer, buffer);
542                                 ref = ref_buffer;
543                                 if (flag)
544                                         *flag |= REF_ISSYMREF;
545                                 continue;
546                         }
547                 }
548
549                 /* Is it a directory? */
550                 if (S_ISDIR(st.st_mode)) {
551                         errno = EISDIR;
552                         return NULL;
553                 }
554
555                 /*
556                  * Anything else, just open it and try to use it as
557                  * a ref
558                  */
559                 fd = open(path, O_RDONLY);
560                 if (fd < 0)
561                         return NULL;
562                 len = read_in_full(fd, buffer, sizeof(buffer)-1);
563                 close(fd);
564                 if (len < 0)
565                         return NULL;
566                 while (len && isspace(buffer[len-1]))
567                         len--;
568                 buffer[len] = '\0';
569
570                 /*
571                  * Is it a symbolic ref?
572                  */
573                 if (prefixcmp(buffer, "ref:"))
574                         break;
575                 buf = buffer + 4;
576                 while (isspace(*buf))
577                         buf++;
578                 if (check_refname_format(buf, REFNAME_ALLOW_ONELEVEL)) {
579                         warning("symbolic reference in %s is formatted incorrectly",
580                                 path);
581                         return NULL;
582                 }
583                 ref = strcpy(ref_buffer, buf);
584                 if (flag)
585                         *flag |= REF_ISSYMREF;
586         }
587         /* Please note that FETCH_HEAD has a second line containing other data. */
588         if (get_sha1_hex(buffer, sha1) || (buffer[40] != '\0' && !isspace(buffer[40]))) {
589                 warning("reference in %s is formatted incorrectly", path);
590                 return NULL;
591         }
592         return ref;
593 }
594
595 /* The argument to filter_refs */
596 struct ref_filter {
597         const char *pattern;
598         each_ref_fn *fn;
599         void *cb_data;
600 };
601
602 int read_ref(const char *ref, unsigned char *sha1)
603 {
604         if (resolve_ref(ref, sha1, 1, NULL))
605                 return 0;
606         return -1;
607 }
608
609 #define DO_FOR_EACH_INCLUDE_BROKEN 01
610 static int do_one_ref(const char *base, each_ref_fn fn, int trim,
611                       int flags, void *cb_data, struct ref_entry *entry)
612 {
613         if (prefixcmp(entry->name, base))
614                 return 0;
615
616         if (!(flags & DO_FOR_EACH_INCLUDE_BROKEN)) {
617                 if (entry->flag & REF_BROKEN)
618                         return 0; /* ignore dangling symref */
619                 if (!has_sha1_file(entry->sha1)) {
620                         error("%s does not point to a valid object!", entry->name);
621                         return 0;
622                 }
623         }
624         current_ref = entry;
625         return fn(entry->name + trim, entry->sha1, entry->flag, cb_data);
626 }
627
628 static int filter_refs(const char *ref, const unsigned char *sha, int flags,
629         void *data)
630 {
631         struct ref_filter *filter = (struct ref_filter *)data;
632         if (fnmatch(filter->pattern, ref, 0))
633                 return 0;
634         return filter->fn(ref, sha, flags, filter->cb_data);
635 }
636
637 int peel_ref(const char *ref, unsigned char *sha1)
638 {
639         int flag;
640         unsigned char base[20];
641         struct object *o;
642
643         if (current_ref && (current_ref->name == ref
644                 || !strcmp(current_ref->name, ref))) {
645                 if (current_ref->flag & REF_KNOWS_PEELED) {
646                         hashcpy(sha1, current_ref->peeled);
647                         return 0;
648                 }
649                 hashcpy(base, current_ref->sha1);
650                 goto fallback;
651         }
652
653         if (!resolve_ref(ref, base, 1, &flag))
654                 return -1;
655
656         if ((flag & REF_ISPACKED)) {
657                 struct ref_array *array = get_packed_refs(NULL);
658                 struct ref_entry *r = search_ref_array(array, ref);
659
660                 if (r != NULL && r->flag & REF_KNOWS_PEELED) {
661                         hashcpy(sha1, r->peeled);
662                         return 0;
663                 }
664         }
665
666 fallback:
667         o = parse_object(base);
668         if (o && o->type == OBJ_TAG) {
669                 o = deref_tag(o, ref, 0);
670                 if (o) {
671                         hashcpy(sha1, o->sha1);
672                         return 0;
673                 }
674         }
675         return -1;
676 }
677
678 static int do_for_each_ref(const char *submodule, const char *base, each_ref_fn fn,
679                            int trim, int flags, void *cb_data)
680 {
681         int retval = 0, i, p = 0, l = 0;
682         struct ref_array *packed = get_packed_refs(submodule);
683         struct ref_array *loose = get_loose_refs(submodule);
684
685         struct ref_array *extra = &extra_refs;
686
687         for (i = 0; i < extra->nr; i++)
688                 retval = do_one_ref(base, fn, trim, flags, cb_data, extra->refs[i]);
689
690         while (p < packed->nr && l < loose->nr) {
691                 struct ref_entry *entry;
692                 int cmp = strcmp(packed->refs[p]->name, loose->refs[l]->name);
693                 if (!cmp) {
694                         p++;
695                         continue;
696                 }
697                 if (cmp > 0) {
698                         entry = loose->refs[l++];
699                 } else {
700                         entry = packed->refs[p++];
701                 }
702                 retval = do_one_ref(base, fn, trim, flags, cb_data, entry);
703                 if (retval)
704                         goto end_each;
705         }
706
707         if (l < loose->nr) {
708                 p = l;
709                 packed = loose;
710         }
711
712         for (; p < packed->nr; p++) {
713                 retval = do_one_ref(base, fn, trim, flags, cb_data, packed->refs[p]);
714                 if (retval)
715                         goto end_each;
716         }
717
718 end_each:
719         current_ref = NULL;
720         return retval;
721 }
722
723
724 static int do_head_ref(const char *submodule, each_ref_fn fn, void *cb_data)
725 {
726         unsigned char sha1[20];
727         int flag;
728
729         if (submodule) {
730                 if (resolve_gitlink_ref(submodule, "HEAD", sha1) == 0)
731                         return fn("HEAD", sha1, 0, cb_data);
732
733                 return 0;
734         }
735
736         if (resolve_ref("HEAD", sha1, 1, &flag))
737                 return fn("HEAD", sha1, flag, cb_data);
738
739         return 0;
740 }
741
742 int head_ref(each_ref_fn fn, void *cb_data)
743 {
744         return do_head_ref(NULL, fn, cb_data);
745 }
746
747 int head_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
748 {
749         return do_head_ref(submodule, fn, cb_data);
750 }
751
752 int for_each_ref(each_ref_fn fn, void *cb_data)
753 {
754         return do_for_each_ref(NULL, "", fn, 0, 0, cb_data);
755 }
756
757 int for_each_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
758 {
759         return do_for_each_ref(submodule, "", fn, 0, 0, cb_data);
760 }
761
762 int for_each_ref_in(const char *prefix, each_ref_fn fn, void *cb_data)
763 {
764         return do_for_each_ref(NULL, prefix, fn, strlen(prefix), 0, cb_data);
765 }
766
767 int for_each_ref_in_submodule(const char *submodule, const char *prefix,
768                 each_ref_fn fn, void *cb_data)
769 {
770         return do_for_each_ref(submodule, prefix, fn, strlen(prefix), 0, cb_data);
771 }
772
773 int for_each_tag_ref(each_ref_fn fn, void *cb_data)
774 {
775         return for_each_ref_in("refs/tags/", fn, cb_data);
776 }
777
778 int for_each_tag_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
779 {
780         return for_each_ref_in_submodule(submodule, "refs/tags/", fn, cb_data);
781 }
782
783 int for_each_branch_ref(each_ref_fn fn, void *cb_data)
784 {
785         return for_each_ref_in("refs/heads/", fn, cb_data);
786 }
787
788 int for_each_branch_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
789 {
790         return for_each_ref_in_submodule(submodule, "refs/heads/", fn, cb_data);
791 }
792
793 int for_each_remote_ref(each_ref_fn fn, void *cb_data)
794 {
795         return for_each_ref_in("refs/remotes/", fn, cb_data);
796 }
797
798 int for_each_remote_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
799 {
800         return for_each_ref_in_submodule(submodule, "refs/remotes/", fn, cb_data);
801 }
802
803 int for_each_replace_ref(each_ref_fn fn, void *cb_data)
804 {
805         return do_for_each_ref(NULL, "refs/replace/", fn, 13, 0, cb_data);
806 }
807
808 int head_ref_namespaced(each_ref_fn fn, void *cb_data)
809 {
810         struct strbuf buf = STRBUF_INIT;
811         int ret = 0;
812         unsigned char sha1[20];
813         int flag;
814
815         strbuf_addf(&buf, "%sHEAD", get_git_namespace());
816         if (resolve_ref(buf.buf, sha1, 1, &flag))
817                 ret = fn(buf.buf, sha1, flag, cb_data);
818         strbuf_release(&buf);
819
820         return ret;
821 }
822
823 int for_each_namespaced_ref(each_ref_fn fn, void *cb_data)
824 {
825         struct strbuf buf = STRBUF_INIT;
826         int ret;
827         strbuf_addf(&buf, "%srefs/", get_git_namespace());
828         ret = do_for_each_ref(NULL, buf.buf, fn, 0, 0, cb_data);
829         strbuf_release(&buf);
830         return ret;
831 }
832
833 int for_each_glob_ref_in(each_ref_fn fn, const char *pattern,
834         const char *prefix, void *cb_data)
835 {
836         struct strbuf real_pattern = STRBUF_INIT;
837         struct ref_filter filter;
838         int ret;
839
840         if (!prefix && prefixcmp(pattern, "refs/"))
841                 strbuf_addstr(&real_pattern, "refs/");
842         else if (prefix)
843                 strbuf_addstr(&real_pattern, prefix);
844         strbuf_addstr(&real_pattern, pattern);
845
846         if (!has_glob_specials(pattern)) {
847                 /* Append implied '/' '*' if not present. */
848                 if (real_pattern.buf[real_pattern.len - 1] != '/')
849                         strbuf_addch(&real_pattern, '/');
850                 /* No need to check for '*', there is none. */
851                 strbuf_addch(&real_pattern, '*');
852         }
853
854         filter.pattern = real_pattern.buf;
855         filter.fn = fn;
856         filter.cb_data = cb_data;
857         ret = for_each_ref(filter_refs, &filter);
858
859         strbuf_release(&real_pattern);
860         return ret;
861 }
862
863 int for_each_glob_ref(each_ref_fn fn, const char *pattern, void *cb_data)
864 {
865         return for_each_glob_ref_in(fn, pattern, NULL, cb_data);
866 }
867
868 int for_each_rawref(each_ref_fn fn, void *cb_data)
869 {
870         return do_for_each_ref(NULL, "", fn, 0,
871                                DO_FOR_EACH_INCLUDE_BROKEN, cb_data);
872 }
873
874 /*
875  * Make sure "ref" is something reasonable to have under ".git/refs/";
876  * We do not like it if:
877  *
878  * - any path component of it begins with ".", or
879  * - it has double dots "..", or
880  * - it has ASCII control character, "~", "^", ":" or SP, anywhere, or
881  * - it ends with a "/".
882  * - it ends with ".lock"
883  * - it contains a "\" (backslash)
884  */
885
886 /* Return true iff ch is not allowed in reference names. */
887 static inline int bad_ref_char(int ch)
888 {
889         if (((unsigned) ch) <= ' ' || ch == 0x7f ||
890             ch == '~' || ch == '^' || ch == ':' || ch == '\\')
891                 return 1;
892         /* 2.13 Pattern Matching Notation */
893         if (ch == '*' || ch == '?' || ch == '[') /* Unsupported */
894                 return 1;
895         return 0;
896 }
897
898 /*
899  * Try to read one refname component from the front of ref.  Return
900  * the length of the component found, or -1 if the component is not
901  * legal.
902  */
903 static int check_refname_component(const char *ref, int flags)
904 {
905         const char *cp;
906         char last = '\0';
907
908         for (cp = ref; ; cp++) {
909                 char ch = *cp;
910                 if (ch == '\0' || ch == '/')
911                         break;
912                 if (bad_ref_char(ch))
913                         return -1; /* Illegal character in refname. */
914                 if (last == '.' && ch == '.')
915                         return -1; /* Refname contains "..". */
916                 if (last == '@' && ch == '{')
917                         return -1; /* Refname contains "@{". */
918                 last = ch;
919         }
920         if (cp == ref)
921                 return -1; /* Component has zero length. */
922         if (ref[0] == '.') {
923                 if (!(flags & REFNAME_DOT_COMPONENT))
924                         return -1; /* Component starts with '.'. */
925                 /*
926                  * Even if leading dots are allowed, don't allow "."
927                  * as a component (".." is prevented by a rule above).
928                  */
929                 if (ref[1] == '\0')
930                         return -1; /* Component equals ".". */
931         }
932         if (cp - ref >= 5 && !memcmp(cp - 5, ".lock", 5))
933                 return -1; /* Refname ends with ".lock". */
934         return cp - ref;
935 }
936
937 int check_refname_format(const char *ref, int flags)
938 {
939         int component_len, component_count = 0;
940
941         while (1) {
942                 /* We are at the start of a path component. */
943                 component_len = check_refname_component(ref, flags);
944                 if (component_len < 0) {
945                         if ((flags & REFNAME_REFSPEC_PATTERN) &&
946                                         ref[0] == '*' &&
947                                         (ref[1] == '\0' || ref[1] == '/')) {
948                                 /* Accept one wildcard as a full refname component. */
949                                 flags &= ~REFNAME_REFSPEC_PATTERN;
950                                 component_len = 1;
951                         } else {
952                                 return -1;
953                         }
954                 }
955                 component_count++;
956                 if (ref[component_len] == '\0')
957                         break;
958                 /* Skip to next component. */
959                 ref += component_len + 1;
960         }
961
962         if (ref[component_len - 1] == '.')
963                 return -1; /* Refname ends with '.'. */
964         if (!(flags & REFNAME_ALLOW_ONELEVEL) && component_count < 2)
965                 return -1; /* Refname has only one component. */
966         return 0;
967 }
968
969 const char *prettify_refname(const char *name)
970 {
971         return name + (
972                 !prefixcmp(name, "refs/heads/") ? 11 :
973                 !prefixcmp(name, "refs/tags/") ? 10 :
974                 !prefixcmp(name, "refs/remotes/") ? 13 :
975                 0);
976 }
977
978 const char *ref_rev_parse_rules[] = {
979         "%.*s",
980         "refs/%.*s",
981         "refs/tags/%.*s",
982         "refs/heads/%.*s",
983         "refs/remotes/%.*s",
984         "refs/remotes/%.*s/HEAD",
985         NULL
986 };
987
988 const char *ref_fetch_rules[] = {
989         "%.*s",
990         "refs/%.*s",
991         "refs/heads/%.*s",
992         NULL
993 };
994
995 int refname_match(const char *abbrev_name, const char *full_name, const char **rules)
996 {
997         const char **p;
998         const int abbrev_name_len = strlen(abbrev_name);
999
1000         for (p = rules; *p; p++) {
1001                 if (!strcmp(full_name, mkpath(*p, abbrev_name_len, abbrev_name))) {
1002                         return 1;
1003                 }
1004         }
1005
1006         return 0;
1007 }
1008
1009 static struct ref_lock *verify_lock(struct ref_lock *lock,
1010         const unsigned char *old_sha1, int mustexist)
1011 {
1012         if (!resolve_ref(lock->ref_name, lock->old_sha1, mustexist, NULL)) {
1013                 error("Can't verify ref %s", lock->ref_name);
1014                 unlock_ref(lock);
1015                 return NULL;
1016         }
1017         if (hashcmp(lock->old_sha1, old_sha1)) {
1018                 error("Ref %s is at %s but expected %s", lock->ref_name,
1019                         sha1_to_hex(lock->old_sha1), sha1_to_hex(old_sha1));
1020                 unlock_ref(lock);
1021                 return NULL;
1022         }
1023         return lock;
1024 }
1025
1026 static int remove_empty_directories(const char *file)
1027 {
1028         /* we want to create a file but there is a directory there;
1029          * if that is an empty directory (or a directory that contains
1030          * only empty directories), remove them.
1031          */
1032         struct strbuf path;
1033         int result;
1034
1035         strbuf_init(&path, 20);
1036         strbuf_addstr(&path, file);
1037
1038         result = remove_dir_recursively(&path, REMOVE_DIR_EMPTY_ONLY);
1039
1040         strbuf_release(&path);
1041
1042         return result;
1043 }
1044
1045 static int is_refname_available(const char *ref, const char *oldref,
1046                                 struct ref_array *array, int quiet)
1047 {
1048         int i, namlen = strlen(ref); /* e.g. 'foo/bar' */
1049         for (i = 0; i < array->nr; i++ ) {
1050                 struct ref_entry *entry = array->refs[i];
1051                 /* entry->name could be 'foo' or 'foo/bar/baz' */
1052                 if (!oldref || strcmp(oldref, entry->name)) {
1053                         int len = strlen(entry->name);
1054                         int cmplen = (namlen < len) ? namlen : len;
1055                         const char *lead = (namlen < len) ? entry->name : ref;
1056                         if (!strncmp(ref, entry->name, cmplen) &&
1057                             lead[cmplen] == '/') {
1058                                 if (!quiet)
1059                                         error("'%s' exists; cannot create '%s'",
1060                                               entry->name, ref);
1061                                 return 0;
1062                         }
1063                 }
1064         }
1065         return 1;
1066 }
1067
1068 static struct ref_lock *lock_ref_sha1_basic(const char *ref, const unsigned char *old_sha1, int flags, int *type_p)
1069 {
1070         char *ref_file;
1071         const char *orig_ref = ref;
1072         struct ref_lock *lock;
1073         int last_errno = 0;
1074         int type, lflags;
1075         int mustexist = (old_sha1 && !is_null_sha1(old_sha1));
1076         int missing = 0;
1077
1078         lock = xcalloc(1, sizeof(struct ref_lock));
1079         lock->lock_fd = -1;
1080
1081         ref = resolve_ref(ref, lock->old_sha1, mustexist, &type);
1082         if (!ref && errno == EISDIR) {
1083                 /* we are trying to lock foo but we used to
1084                  * have foo/bar which now does not exist;
1085                  * it is normal for the empty directory 'foo'
1086                  * to remain.
1087                  */
1088                 ref_file = git_path("%s", orig_ref);
1089                 if (remove_empty_directories(ref_file)) {
1090                         last_errno = errno;
1091                         error("there are still refs under '%s'", orig_ref);
1092                         goto error_return;
1093                 }
1094                 ref = resolve_ref(orig_ref, lock->old_sha1, mustexist, &type);
1095         }
1096         if (type_p)
1097             *type_p = type;
1098         if (!ref) {
1099                 last_errno = errno;
1100                 error("unable to resolve reference %s: %s",
1101                         orig_ref, strerror(errno));
1102                 goto error_return;
1103         }
1104         missing = is_null_sha1(lock->old_sha1);
1105         /* When the ref did not exist and we are creating it,
1106          * make sure there is no existing ref that is packed
1107          * whose name begins with our refname, nor a ref whose
1108          * name is a proper prefix of our refname.
1109          */
1110         if (missing &&
1111              !is_refname_available(ref, NULL, get_packed_refs(NULL), 0)) {
1112                 last_errno = ENOTDIR;
1113                 goto error_return;
1114         }
1115
1116         lock->lk = xcalloc(1, sizeof(struct lock_file));
1117
1118         lflags = LOCK_DIE_ON_ERROR;
1119         if (flags & REF_NODEREF) {
1120                 ref = orig_ref;
1121                 lflags |= LOCK_NODEREF;
1122         }
1123         lock->ref_name = xstrdup(ref);
1124         lock->orig_ref_name = xstrdup(orig_ref);
1125         ref_file = git_path("%s", ref);
1126         if (missing)
1127                 lock->force_write = 1;
1128         if ((flags & REF_NODEREF) && (type & REF_ISSYMREF))
1129                 lock->force_write = 1;
1130
1131         if (safe_create_leading_directories(ref_file)) {
1132                 last_errno = errno;
1133                 error("unable to create directory for %s", ref_file);
1134                 goto error_return;
1135         }
1136
1137         lock->lock_fd = hold_lock_file_for_update(lock->lk, ref_file, lflags);
1138         return old_sha1 ? verify_lock(lock, old_sha1, mustexist) : lock;
1139
1140  error_return:
1141         unlock_ref(lock);
1142         errno = last_errno;
1143         return NULL;
1144 }
1145
1146 struct ref_lock *lock_ref_sha1(const char *ref, const unsigned char *old_sha1)
1147 {
1148         char refpath[PATH_MAX];
1149         if (check_refname_format(ref, 0))
1150                 return NULL;
1151         strcpy(refpath, mkpath("refs/%s", ref));
1152         return lock_ref_sha1_basic(refpath, old_sha1, 0, NULL);
1153 }
1154
1155 struct ref_lock *lock_any_ref_for_update(const char *ref, const unsigned char *old_sha1, int flags)
1156 {
1157         if (check_refname_format(ref, REFNAME_ALLOW_ONELEVEL))
1158                 return NULL;
1159         return lock_ref_sha1_basic(ref, old_sha1, flags, NULL);
1160 }
1161
1162 static struct lock_file packlock;
1163
1164 static int repack_without_ref(const char *refname)
1165 {
1166         struct ref_array *packed;
1167         struct ref_entry *ref;
1168         int fd, i;
1169
1170         packed = get_packed_refs(NULL);
1171         ref = search_ref_array(packed, refname);
1172         if (ref == NULL)
1173                 return 0;
1174         fd = hold_lock_file_for_update(&packlock, git_path("packed-refs"), 0);
1175         if (fd < 0) {
1176                 unable_to_lock_error(git_path("packed-refs"), errno);
1177                 return error("cannot delete '%s' from packed refs", refname);
1178         }
1179
1180         for (i = 0; i < packed->nr; i++) {
1181                 char line[PATH_MAX + 100];
1182                 int len;
1183
1184                 ref = packed->refs[i];
1185
1186                 if (!strcmp(refname, ref->name))
1187                         continue;
1188                 len = snprintf(line, sizeof(line), "%s %s\n",
1189                                sha1_to_hex(ref->sha1), ref->name);
1190                 /* this should not happen but just being defensive */
1191                 if (len > sizeof(line))
1192                         die("too long a refname '%s'", ref->name);
1193                 write_or_die(fd, line, len);
1194         }
1195         return commit_lock_file(&packlock);
1196 }
1197
1198 int delete_ref(const char *refname, const unsigned char *sha1, int delopt)
1199 {
1200         struct ref_lock *lock;
1201         int err, i = 0, ret = 0, flag = 0;
1202
1203         lock = lock_ref_sha1_basic(refname, sha1, 0, &flag);
1204         if (!lock)
1205                 return 1;
1206         if (!(flag & REF_ISPACKED) || flag & REF_ISSYMREF) {
1207                 /* loose */
1208                 const char *path;
1209
1210                 if (!(delopt & REF_NODEREF)) {
1211                         i = strlen(lock->lk->filename) - 5; /* .lock */
1212                         lock->lk->filename[i] = 0;
1213                         path = lock->lk->filename;
1214                 } else {
1215                         path = git_path("%s", refname);
1216                 }
1217                 err = unlink_or_warn(path);
1218                 if (err && errno != ENOENT)
1219                         ret = 1;
1220
1221                 if (!(delopt & REF_NODEREF))
1222                         lock->lk->filename[i] = '.';
1223         }
1224         /* removing the loose one could have resurrected an earlier
1225          * packed one.  Also, if it was not loose we need to repack
1226          * without it.
1227          */
1228         ret |= repack_without_ref(refname);
1229
1230         unlink_or_warn(git_path("logs/%s", lock->ref_name));
1231         invalidate_cached_refs();
1232         unlock_ref(lock);
1233         return ret;
1234 }
1235
1236 /*
1237  * People using contrib's git-new-workdir have .git/logs/refs ->
1238  * /some/other/path/.git/logs/refs, and that may live on another device.
1239  *
1240  * IOW, to avoid cross device rename errors, the temporary renamed log must
1241  * live into logs/refs.
1242  */
1243 #define TMP_RENAMED_LOG  "logs/refs/.tmp-renamed-log"
1244
1245 int rename_ref(const char *oldref, const char *newref, const char *logmsg)
1246 {
1247         static const char renamed_ref[] = "RENAMED-REF";
1248         unsigned char sha1[20], orig_sha1[20];
1249         int flag = 0, logmoved = 0;
1250         struct ref_lock *lock;
1251         struct stat loginfo;
1252         int log = !lstat(git_path("logs/%s", oldref), &loginfo);
1253         const char *symref = NULL;
1254
1255         if (log && S_ISLNK(loginfo.st_mode))
1256                 return error("reflog for %s is a symlink", oldref);
1257
1258         symref = resolve_ref(oldref, orig_sha1, 1, &flag);
1259         if (flag & REF_ISSYMREF)
1260                 return error("refname %s is a symbolic ref, renaming it is not supported",
1261                         oldref);
1262         if (!symref)
1263                 return error("refname %s not found", oldref);
1264
1265         if (!is_refname_available(newref, oldref, get_packed_refs(NULL), 0))
1266                 return 1;
1267
1268         if (!is_refname_available(newref, oldref, get_loose_refs(NULL), 0))
1269                 return 1;
1270
1271         lock = lock_ref_sha1_basic(renamed_ref, NULL, 0, NULL);
1272         if (!lock)
1273                 return error("unable to lock %s", renamed_ref);
1274         lock->force_write = 1;
1275         if (write_ref_sha1(lock, orig_sha1, logmsg))
1276                 return error("unable to save current sha1 in %s", renamed_ref);
1277
1278         if (log && rename(git_path("logs/%s", oldref), git_path(TMP_RENAMED_LOG)))
1279                 return error("unable to move logfile logs/%s to "TMP_RENAMED_LOG": %s",
1280                         oldref, strerror(errno));
1281
1282         if (delete_ref(oldref, orig_sha1, REF_NODEREF)) {
1283                 error("unable to delete old %s", oldref);
1284                 goto rollback;
1285         }
1286
1287         if (resolve_ref(newref, sha1, 1, &flag) && delete_ref(newref, sha1, REF_NODEREF)) {
1288                 if (errno==EISDIR) {
1289                         if (remove_empty_directories(git_path("%s", newref))) {
1290                                 error("Directory not empty: %s", newref);
1291                                 goto rollback;
1292                         }
1293                 } else {
1294                         error("unable to delete existing %s", newref);
1295                         goto rollback;
1296                 }
1297         }
1298
1299         if (log && safe_create_leading_directories(git_path("logs/%s", newref))) {
1300                 error("unable to create directory for %s", newref);
1301                 goto rollback;
1302         }
1303
1304  retry:
1305         if (log && rename(git_path(TMP_RENAMED_LOG), git_path("logs/%s", newref))) {
1306                 if (errno==EISDIR || errno==ENOTDIR) {
1307                         /*
1308                          * rename(a, b) when b is an existing
1309                          * directory ought to result in ISDIR, but
1310                          * Solaris 5.8 gives ENOTDIR.  Sheesh.
1311                          */
1312                         if (remove_empty_directories(git_path("logs/%s", newref))) {
1313                                 error("Directory not empty: logs/%s", newref);
1314                                 goto rollback;
1315                         }
1316                         goto retry;
1317                 } else {
1318                         error("unable to move logfile "TMP_RENAMED_LOG" to logs/%s: %s",
1319                                 newref, strerror(errno));
1320                         goto rollback;
1321                 }
1322         }
1323         logmoved = log;
1324
1325         lock = lock_ref_sha1_basic(newref, NULL, 0, NULL);
1326         if (!lock) {
1327                 error("unable to lock %s for update", newref);
1328                 goto rollback;
1329         }
1330         lock->force_write = 1;
1331         hashcpy(lock->old_sha1, orig_sha1);
1332         if (write_ref_sha1(lock, orig_sha1, logmsg)) {
1333                 error("unable to write current sha1 into %s", newref);
1334                 goto rollback;
1335         }
1336
1337         return 0;
1338
1339  rollback:
1340         lock = lock_ref_sha1_basic(oldref, NULL, 0, NULL);
1341         if (!lock) {
1342                 error("unable to lock %s for rollback", oldref);
1343                 goto rollbacklog;
1344         }
1345
1346         lock->force_write = 1;
1347         flag = log_all_ref_updates;
1348         log_all_ref_updates = 0;
1349         if (write_ref_sha1(lock, orig_sha1, NULL))
1350                 error("unable to write current sha1 into %s", oldref);
1351         log_all_ref_updates = flag;
1352
1353  rollbacklog:
1354         if (logmoved && rename(git_path("logs/%s", newref), git_path("logs/%s", oldref)))
1355                 error("unable to restore logfile %s from %s: %s",
1356                         oldref, newref, strerror(errno));
1357         if (!logmoved && log &&
1358             rename(git_path(TMP_RENAMED_LOG), git_path("logs/%s", oldref)))
1359                 error("unable to restore logfile %s from "TMP_RENAMED_LOG": %s",
1360                         oldref, strerror(errno));
1361
1362         return 1;
1363 }
1364
1365 int close_ref(struct ref_lock *lock)
1366 {
1367         if (close_lock_file(lock->lk))
1368                 return -1;
1369         lock->lock_fd = -1;
1370         return 0;
1371 }
1372
1373 int commit_ref(struct ref_lock *lock)
1374 {
1375         if (commit_lock_file(lock->lk))
1376                 return -1;
1377         lock->lock_fd = -1;
1378         return 0;
1379 }
1380
1381 void unlock_ref(struct ref_lock *lock)
1382 {
1383         /* Do not free lock->lk -- atexit() still looks at them */
1384         if (lock->lk)
1385                 rollback_lock_file(lock->lk);
1386         free(lock->ref_name);
1387         free(lock->orig_ref_name);
1388         free(lock);
1389 }
1390
1391 /*
1392  * copy the reflog message msg to buf, which has been allocated sufficiently
1393  * large, while cleaning up the whitespaces.  Especially, convert LF to space,
1394  * because reflog file is one line per entry.
1395  */
1396 static int copy_msg(char *buf, const char *msg)
1397 {
1398         char *cp = buf;
1399         char c;
1400         int wasspace = 1;
1401
1402         *cp++ = '\t';
1403         while ((c = *msg++)) {
1404                 if (wasspace && isspace(c))
1405                         continue;
1406                 wasspace = isspace(c);
1407                 if (wasspace)
1408                         c = ' ';
1409                 *cp++ = c;
1410         }
1411         while (buf < cp && isspace(cp[-1]))
1412                 cp--;
1413         *cp++ = '\n';
1414         return cp - buf;
1415 }
1416
1417 int log_ref_setup(const char *ref_name, char *logfile, int bufsize)
1418 {
1419         int logfd, oflags = O_APPEND | O_WRONLY;
1420
1421         git_snpath(logfile, bufsize, "logs/%s", ref_name);
1422         if (log_all_ref_updates &&
1423             (!prefixcmp(ref_name, "refs/heads/") ||
1424              !prefixcmp(ref_name, "refs/remotes/") ||
1425              !prefixcmp(ref_name, "refs/notes/") ||
1426              !strcmp(ref_name, "HEAD"))) {
1427                 if (safe_create_leading_directories(logfile) < 0)
1428                         return error("unable to create directory for %s",
1429                                      logfile);
1430                 oflags |= O_CREAT;
1431         }
1432
1433         logfd = open(logfile, oflags, 0666);
1434         if (logfd < 0) {
1435                 if (!(oflags & O_CREAT) && errno == ENOENT)
1436                         return 0;
1437
1438                 if ((oflags & O_CREAT) && errno == EISDIR) {
1439                         if (remove_empty_directories(logfile)) {
1440                                 return error("There are still logs under '%s'",
1441                                              logfile);
1442                         }
1443                         logfd = open(logfile, oflags, 0666);
1444                 }
1445
1446                 if (logfd < 0)
1447                         return error("Unable to append to %s: %s",
1448                                      logfile, strerror(errno));
1449         }
1450
1451         adjust_shared_perm(logfile);
1452         close(logfd);
1453         return 0;
1454 }
1455
1456 static int log_ref_write(const char *ref_name, const unsigned char *old_sha1,
1457                          const unsigned char *new_sha1, const char *msg)
1458 {
1459         int logfd, result, written, oflags = O_APPEND | O_WRONLY;
1460         unsigned maxlen, len;
1461         int msglen;
1462         char log_file[PATH_MAX];
1463         char *logrec;
1464         const char *committer;
1465
1466         if (log_all_ref_updates < 0)
1467                 log_all_ref_updates = !is_bare_repository();
1468
1469         result = log_ref_setup(ref_name, log_file, sizeof(log_file));
1470         if (result)
1471                 return result;
1472
1473         logfd = open(log_file, oflags);
1474         if (logfd < 0)
1475                 return 0;
1476         msglen = msg ? strlen(msg) : 0;
1477         committer = git_committer_info(0);
1478         maxlen = strlen(committer) + msglen + 100;
1479         logrec = xmalloc(maxlen);
1480         len = sprintf(logrec, "%s %s %s\n",
1481                       sha1_to_hex(old_sha1),
1482                       sha1_to_hex(new_sha1),
1483                       committer);
1484         if (msglen)
1485                 len += copy_msg(logrec + len - 1, msg) - 1;
1486         written = len <= maxlen ? write_in_full(logfd, logrec, len) : -1;
1487         free(logrec);
1488         if (close(logfd) != 0 || written != len)
1489                 return error("Unable to append to %s", log_file);
1490         return 0;
1491 }
1492
1493 static int is_branch(const char *refname)
1494 {
1495         return !strcmp(refname, "HEAD") || !prefixcmp(refname, "refs/heads/");
1496 }
1497
1498 int write_ref_sha1(struct ref_lock *lock,
1499         const unsigned char *sha1, const char *logmsg)
1500 {
1501         static char term = '\n';
1502         struct object *o;
1503
1504         if (!lock)
1505                 return -1;
1506         if (!lock->force_write && !hashcmp(lock->old_sha1, sha1)) {
1507                 unlock_ref(lock);
1508                 return 0;
1509         }
1510         o = parse_object(sha1);
1511         if (!o) {
1512                 error("Trying to write ref %s with nonexistent object %s",
1513                         lock->ref_name, sha1_to_hex(sha1));
1514                 unlock_ref(lock);
1515                 return -1;
1516         }
1517         if (o->type != OBJ_COMMIT && is_branch(lock->ref_name)) {
1518                 error("Trying to write non-commit object %s to branch %s",
1519                         sha1_to_hex(sha1), lock->ref_name);
1520                 unlock_ref(lock);
1521                 return -1;
1522         }
1523         if (write_in_full(lock->lock_fd, sha1_to_hex(sha1), 40) != 40 ||
1524             write_in_full(lock->lock_fd, &term, 1) != 1
1525                 || close_ref(lock) < 0) {
1526                 error("Couldn't write %s", lock->lk->filename);
1527                 unlock_ref(lock);
1528                 return -1;
1529         }
1530         invalidate_cached_refs();
1531         if (log_ref_write(lock->ref_name, lock->old_sha1, sha1, logmsg) < 0 ||
1532             (strcmp(lock->ref_name, lock->orig_ref_name) &&
1533              log_ref_write(lock->orig_ref_name, lock->old_sha1, sha1, logmsg) < 0)) {
1534                 unlock_ref(lock);
1535                 return -1;
1536         }
1537         if (strcmp(lock->orig_ref_name, "HEAD") != 0) {
1538                 /*
1539                  * Special hack: If a branch is updated directly and HEAD
1540                  * points to it (may happen on the remote side of a push
1541                  * for example) then logically the HEAD reflog should be
1542                  * updated too.
1543                  * A generic solution implies reverse symref information,
1544                  * but finding all symrefs pointing to the given branch
1545                  * would be rather costly for this rare event (the direct
1546                  * update of a branch) to be worth it.  So let's cheat and
1547                  * check with HEAD only which should cover 99% of all usage
1548                  * scenarios (even 100% of the default ones).
1549                  */
1550                 unsigned char head_sha1[20];
1551                 int head_flag;
1552                 const char *head_ref;
1553                 head_ref = resolve_ref("HEAD", head_sha1, 1, &head_flag);
1554                 if (head_ref && (head_flag & REF_ISSYMREF) &&
1555                     !strcmp(head_ref, lock->ref_name))
1556                         log_ref_write("HEAD", lock->old_sha1, sha1, logmsg);
1557         }
1558         if (commit_ref(lock)) {
1559                 error("Couldn't set %s", lock->ref_name);
1560                 unlock_ref(lock);
1561                 return -1;
1562         }
1563         unlock_ref(lock);
1564         return 0;
1565 }
1566
1567 int create_symref(const char *ref_target, const char *refs_heads_master,
1568                   const char *logmsg)
1569 {
1570         const char *lockpath;
1571         char ref[1000];
1572         int fd, len, written;
1573         char *git_HEAD = git_pathdup("%s", ref_target);
1574         unsigned char old_sha1[20], new_sha1[20];
1575
1576         if (logmsg && read_ref(ref_target, old_sha1))
1577                 hashclr(old_sha1);
1578
1579         if (safe_create_leading_directories(git_HEAD) < 0)
1580                 return error("unable to create directory for %s", git_HEAD);
1581
1582 #ifndef NO_SYMLINK_HEAD
1583         if (prefer_symlink_refs) {
1584                 unlink(git_HEAD);
1585                 if (!symlink(refs_heads_master, git_HEAD))
1586                         goto done;
1587                 fprintf(stderr, "no symlink - falling back to symbolic ref\n");
1588         }
1589 #endif
1590
1591         len = snprintf(ref, sizeof(ref), "ref: %s\n", refs_heads_master);
1592         if (sizeof(ref) <= len) {
1593                 error("refname too long: %s", refs_heads_master);
1594                 goto error_free_return;
1595         }
1596         lockpath = mkpath("%s.lock", git_HEAD);
1597         fd = open(lockpath, O_CREAT | O_EXCL | O_WRONLY, 0666);
1598         if (fd < 0) {
1599                 error("Unable to open %s for writing", lockpath);
1600                 goto error_free_return;
1601         }
1602         written = write_in_full(fd, ref, len);
1603         if (close(fd) != 0 || written != len) {
1604                 error("Unable to write to %s", lockpath);
1605                 goto error_unlink_return;
1606         }
1607         if (rename(lockpath, git_HEAD) < 0) {
1608                 error("Unable to create %s", git_HEAD);
1609                 goto error_unlink_return;
1610         }
1611         if (adjust_shared_perm(git_HEAD)) {
1612                 error("Unable to fix permissions on %s", lockpath);
1613         error_unlink_return:
1614                 unlink_or_warn(lockpath);
1615         error_free_return:
1616                 free(git_HEAD);
1617                 return -1;
1618         }
1619
1620 #ifndef NO_SYMLINK_HEAD
1621         done:
1622 #endif
1623         if (logmsg && !read_ref(refs_heads_master, new_sha1))
1624                 log_ref_write(ref_target, old_sha1, new_sha1, logmsg);
1625
1626         free(git_HEAD);
1627         return 0;
1628 }
1629
1630 static char *ref_msg(const char *line, const char *endp)
1631 {
1632         const char *ep;
1633         line += 82;
1634         ep = memchr(line, '\n', endp - line);
1635         if (!ep)
1636                 ep = endp;
1637         return xmemdupz(line, ep - line);
1638 }
1639
1640 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)
1641 {
1642         const char *logfile, *logdata, *logend, *rec, *lastgt, *lastrec;
1643         char *tz_c;
1644         int logfd, tz, reccnt = 0;
1645         struct stat st;
1646         unsigned long date;
1647         unsigned char logged_sha1[20];
1648         void *log_mapped;
1649         size_t mapsz;
1650
1651         logfile = git_path("logs/%s", ref);
1652         logfd = open(logfile, O_RDONLY, 0);
1653         if (logfd < 0)
1654                 die_errno("Unable to read log '%s'", logfile);
1655         fstat(logfd, &st);
1656         if (!st.st_size)
1657                 die("Log %s is empty.", logfile);
1658         mapsz = xsize_t(st.st_size);
1659         log_mapped = xmmap(NULL, mapsz, PROT_READ, MAP_PRIVATE, logfd, 0);
1660         logdata = log_mapped;
1661         close(logfd);
1662
1663         lastrec = NULL;
1664         rec = logend = logdata + st.st_size;
1665         while (logdata < rec) {
1666                 reccnt++;
1667                 if (logdata < rec && *(rec-1) == '\n')
1668                         rec--;
1669                 lastgt = NULL;
1670                 while (logdata < rec && *(rec-1) != '\n') {
1671                         rec--;
1672                         if (*rec == '>')
1673                                 lastgt = rec;
1674                 }
1675                 if (!lastgt)
1676                         die("Log %s is corrupt.", logfile);
1677                 date = strtoul(lastgt + 1, &tz_c, 10);
1678                 if (date <= at_time || cnt == 0) {
1679                         tz = strtoul(tz_c, NULL, 10);
1680                         if (msg)
1681                                 *msg = ref_msg(rec, logend);
1682                         if (cutoff_time)
1683                                 *cutoff_time = date;
1684                         if (cutoff_tz)
1685                                 *cutoff_tz = tz;
1686                         if (cutoff_cnt)
1687                                 *cutoff_cnt = reccnt - 1;
1688                         if (lastrec) {
1689                                 if (get_sha1_hex(lastrec, logged_sha1))
1690                                         die("Log %s is corrupt.", logfile);
1691                                 if (get_sha1_hex(rec + 41, sha1))
1692                                         die("Log %s is corrupt.", logfile);
1693                                 if (hashcmp(logged_sha1, sha1)) {
1694                                         warning("Log %s has gap after %s.",
1695                                                 logfile, show_date(date, tz, DATE_RFC2822));
1696                                 }
1697                         }
1698                         else if (date == at_time) {
1699                                 if (get_sha1_hex(rec + 41, sha1))
1700                                         die("Log %s is corrupt.", logfile);
1701                         }
1702                         else {
1703                                 if (get_sha1_hex(rec + 41, logged_sha1))
1704                                         die("Log %s is corrupt.", logfile);
1705                                 if (hashcmp(logged_sha1, sha1)) {
1706                                         warning("Log %s unexpectedly ended on %s.",
1707                                                 logfile, show_date(date, tz, DATE_RFC2822));
1708                                 }
1709                         }
1710                         munmap(log_mapped, mapsz);
1711                         return 0;
1712                 }
1713                 lastrec = rec;
1714                 if (cnt > 0)
1715                         cnt--;
1716         }
1717
1718         rec = logdata;
1719         while (rec < logend && *rec != '>' && *rec != '\n')
1720                 rec++;
1721         if (rec == logend || *rec == '\n')
1722                 die("Log %s is corrupt.", logfile);
1723         date = strtoul(rec + 1, &tz_c, 10);
1724         tz = strtoul(tz_c, NULL, 10);
1725         if (get_sha1_hex(logdata, sha1))
1726                 die("Log %s is corrupt.", logfile);
1727         if (is_null_sha1(sha1)) {
1728                 if (get_sha1_hex(logdata + 41, sha1))
1729                         die("Log %s is corrupt.", logfile);
1730         }
1731         if (msg)
1732                 *msg = ref_msg(logdata, logend);
1733         munmap(log_mapped, mapsz);
1734
1735         if (cutoff_time)
1736                 *cutoff_time = date;
1737         if (cutoff_tz)
1738                 *cutoff_tz = tz;
1739         if (cutoff_cnt)
1740                 *cutoff_cnt = reccnt;
1741         return 1;
1742 }
1743
1744 int for_each_recent_reflog_ent(const char *ref, each_reflog_ent_fn fn, long ofs, void *cb_data)
1745 {
1746         const char *logfile;
1747         FILE *logfp;
1748         struct strbuf sb = STRBUF_INIT;
1749         int ret = 0;
1750
1751         logfile = git_path("logs/%s", ref);
1752         logfp = fopen(logfile, "r");
1753         if (!logfp)
1754                 return -1;
1755
1756         if (ofs) {
1757                 struct stat statbuf;
1758                 if (fstat(fileno(logfp), &statbuf) ||
1759                     statbuf.st_size < ofs ||
1760                     fseek(logfp, -ofs, SEEK_END) ||
1761                     strbuf_getwholeline(&sb, logfp, '\n')) {
1762                         fclose(logfp);
1763                         strbuf_release(&sb);
1764                         return -1;
1765                 }
1766         }
1767
1768         while (!strbuf_getwholeline(&sb, logfp, '\n')) {
1769                 unsigned char osha1[20], nsha1[20];
1770                 char *email_end, *message;
1771                 unsigned long timestamp;
1772                 int tz;
1773
1774                 /* old SP new SP name <email> SP time TAB msg LF */
1775                 if (sb.len < 83 || sb.buf[sb.len - 1] != '\n' ||
1776                     get_sha1_hex(sb.buf, osha1) || sb.buf[40] != ' ' ||
1777                     get_sha1_hex(sb.buf + 41, nsha1) || sb.buf[81] != ' ' ||
1778                     !(email_end = strchr(sb.buf + 82, '>')) ||
1779                     email_end[1] != ' ' ||
1780                     !(timestamp = strtoul(email_end + 2, &message, 10)) ||
1781                     !message || message[0] != ' ' ||
1782                     (message[1] != '+' && message[1] != '-') ||
1783                     !isdigit(message[2]) || !isdigit(message[3]) ||
1784                     !isdigit(message[4]) || !isdigit(message[5]))
1785                         continue; /* corrupt? */
1786                 email_end[1] = '\0';
1787                 tz = strtol(message + 1, NULL, 10);
1788                 if (message[6] != '\t')
1789                         message += 6;
1790                 else
1791                         message += 7;
1792                 ret = fn(osha1, nsha1, sb.buf + 82, timestamp, tz, message,
1793                          cb_data);
1794                 if (ret)
1795                         break;
1796         }
1797         fclose(logfp);
1798         strbuf_release(&sb);
1799         return ret;
1800 }
1801
1802 int for_each_reflog_ent(const char *ref, each_reflog_ent_fn fn, void *cb_data)
1803 {
1804         return for_each_recent_reflog_ent(ref, fn, 0, cb_data);
1805 }
1806
1807 static int do_for_each_reflog(const char *base, each_ref_fn fn, void *cb_data)
1808 {
1809         DIR *dir = opendir(git_path("logs/%s", base));
1810         int retval = 0;
1811
1812         if (dir) {
1813                 struct dirent *de;
1814                 int baselen = strlen(base);
1815                 char *log = xmalloc(baselen + 257);
1816
1817                 memcpy(log, base, baselen);
1818                 if (baselen && base[baselen-1] != '/')
1819                         log[baselen++] = '/';
1820
1821                 while ((de = readdir(dir)) != NULL) {
1822                         struct stat st;
1823                         int namelen;
1824
1825                         if (de->d_name[0] == '.')
1826                                 continue;
1827                         namelen = strlen(de->d_name);
1828                         if (namelen > 255)
1829                                 continue;
1830                         if (has_extension(de->d_name, ".lock"))
1831                                 continue;
1832                         memcpy(log + baselen, de->d_name, namelen+1);
1833                         if (stat(git_path("logs/%s", log), &st) < 0)
1834                                 continue;
1835                         if (S_ISDIR(st.st_mode)) {
1836                                 retval = do_for_each_reflog(log, fn, cb_data);
1837                         } else {
1838                                 unsigned char sha1[20];
1839                                 if (!resolve_ref(log, sha1, 0, NULL))
1840                                         retval = error("bad ref for %s", log);
1841                                 else
1842                                         retval = fn(log, sha1, 0, cb_data);
1843                         }
1844                         if (retval)
1845                                 break;
1846                 }
1847                 free(log);
1848                 closedir(dir);
1849         }
1850         else if (*base)
1851                 return errno;
1852         return retval;
1853 }
1854
1855 int for_each_reflog(each_ref_fn fn, void *cb_data)
1856 {
1857         return do_for_each_reflog("", fn, cb_data);
1858 }
1859
1860 int update_ref(const char *action, const char *refname,
1861                 const unsigned char *sha1, const unsigned char *oldval,
1862                 int flags, enum action_on_err onerr)
1863 {
1864         static struct ref_lock *lock;
1865         lock = lock_any_ref_for_update(refname, oldval, flags);
1866         if (!lock) {
1867                 const char *str = "Cannot lock the ref '%s'.";
1868                 switch (onerr) {
1869                 case MSG_ON_ERR: error(str, refname); break;
1870                 case DIE_ON_ERR: die(str, refname); break;
1871                 case QUIET_ON_ERR: break;
1872                 }
1873                 return 1;
1874         }
1875         if (write_ref_sha1(lock, sha1, action) < 0) {
1876                 const char *str = "Cannot update the ref '%s'.";
1877                 switch (onerr) {
1878                 case MSG_ON_ERR: error(str, refname); break;
1879                 case DIE_ON_ERR: die(str, refname); break;
1880                 case QUIET_ON_ERR: break;
1881                 }
1882                 return 1;
1883         }
1884         return 0;
1885 }
1886
1887 int ref_exists(const char *refname)
1888 {
1889         unsigned char sha1[20];
1890         return !!resolve_ref(refname, sha1, 1, NULL);
1891 }
1892
1893 struct ref *find_ref_by_name(const struct ref *list, const char *name)
1894 {
1895         for ( ; list; list = list->next)
1896                 if (!strcmp(list->name, name))
1897                         return (struct ref *)list;
1898         return NULL;
1899 }
1900
1901 /*
1902  * generate a format suitable for scanf from a ref_rev_parse_rules
1903  * rule, that is replace the "%.*s" spec with a "%s" spec
1904  */
1905 static void gen_scanf_fmt(char *scanf_fmt, const char *rule)
1906 {
1907         char *spec;
1908
1909         spec = strstr(rule, "%.*s");
1910         if (!spec || strstr(spec + 4, "%.*s"))
1911                 die("invalid rule in ref_rev_parse_rules: %s", rule);
1912
1913         /* copy all until spec */
1914         strncpy(scanf_fmt, rule, spec - rule);
1915         scanf_fmt[spec - rule] = '\0';
1916         /* copy new spec */
1917         strcat(scanf_fmt, "%s");
1918         /* copy remaining rule */
1919         strcat(scanf_fmt, spec + 4);
1920
1921         return;
1922 }
1923
1924 char *shorten_unambiguous_ref(const char *ref, int strict)
1925 {
1926         int i;
1927         static char **scanf_fmts;
1928         static int nr_rules;
1929         char *short_name;
1930
1931         /* pre generate scanf formats from ref_rev_parse_rules[] */
1932         if (!nr_rules) {
1933                 size_t total_len = 0;
1934
1935                 /* the rule list is NULL terminated, count them first */
1936                 for (; ref_rev_parse_rules[nr_rules]; nr_rules++)
1937                         /* no +1 because strlen("%s") < strlen("%.*s") */
1938                         total_len += strlen(ref_rev_parse_rules[nr_rules]);
1939
1940                 scanf_fmts = xmalloc(nr_rules * sizeof(char *) + total_len);
1941
1942                 total_len = 0;
1943                 for (i = 0; i < nr_rules; i++) {
1944                         scanf_fmts[i] = (char *)&scanf_fmts[nr_rules]
1945                                         + total_len;
1946                         gen_scanf_fmt(scanf_fmts[i], ref_rev_parse_rules[i]);
1947                         total_len += strlen(ref_rev_parse_rules[i]);
1948                 }
1949         }
1950
1951         /* bail out if there are no rules */
1952         if (!nr_rules)
1953                 return xstrdup(ref);
1954
1955         /* buffer for scanf result, at most ref must fit */
1956         short_name = xstrdup(ref);
1957
1958         /* skip first rule, it will always match */
1959         for (i = nr_rules - 1; i > 0 ; --i) {
1960                 int j;
1961                 int rules_to_fail = i;
1962                 int short_name_len;
1963
1964                 if (1 != sscanf(ref, scanf_fmts[i], short_name))
1965                         continue;
1966
1967                 short_name_len = strlen(short_name);
1968
1969                 /*
1970                  * in strict mode, all (except the matched one) rules
1971                  * must fail to resolve to a valid non-ambiguous ref
1972                  */
1973                 if (strict)
1974                         rules_to_fail = nr_rules;
1975
1976                 /*
1977                  * check if the short name resolves to a valid ref,
1978                  * but use only rules prior to the matched one
1979                  */
1980                 for (j = 0; j < rules_to_fail; j++) {
1981                         const char *rule = ref_rev_parse_rules[j];
1982                         unsigned char short_objectname[20];
1983                         char refname[PATH_MAX];
1984
1985                         /* skip matched rule */
1986                         if (i == j)
1987                                 continue;
1988
1989                         /*
1990                          * the short name is ambiguous, if it resolves
1991                          * (with this previous rule) to a valid ref
1992                          * read_ref() returns 0 on success
1993                          */
1994                         mksnpath(refname, sizeof(refname),
1995                                  rule, short_name_len, short_name);
1996                         if (!read_ref(refname, short_objectname))
1997                                 break;
1998                 }
1999
2000                 /*
2001                  * short name is non-ambiguous if all previous rules
2002                  * haven't resolved to a valid ref
2003                  */
2004                 if (j == rules_to_fail)
2005                         return short_name;
2006         }
2007
2008         free(short_name);
2009         return xstrdup(ref);
2010 }