Merge branch 'maint-1.7.7' into maint
[git] / refs.c
1 #include "cache.h"
2 #include "refs.h"
3 #include "object.h"
4 #include "tag.h"
5 #include "dir.h"
6
7 /* ISSYMREF=0x01, ISPACKED=0x02 and ISBROKEN=0x04 are public interfaces */
8 #define REF_KNOWS_PEELED 0x10
9
10 struct ref_entry {
11         unsigned char flag; /* ISSYMREF? ISPACKED? */
12         unsigned char sha1[20];
13         unsigned char peeled[20];
14         char name[FLEX_ARRAY];
15 };
16
17 struct ref_array {
18         int nr, alloc;
19         struct ref_entry **refs;
20 };
21
22 static const char *parse_ref_line(char *line, unsigned char *sha1)
23 {
24         /*
25          * 42: the answer to everything.
26          *
27          * In this case, it happens to be the answer to
28          *  40 (length of sha1 hex representation)
29          *  +1 (space in between hex and name)
30          *  +1 (newline at the end of the line)
31          */
32         int len = strlen(line) - 42;
33
34         if (len <= 0)
35                 return NULL;
36         if (get_sha1_hex(line, sha1) < 0)
37                 return NULL;
38         if (!isspace(line[40]))
39                 return NULL;
40         line += 41;
41         if (isspace(*line))
42                 return NULL;
43         if (line[len] != '\n')
44                 return NULL;
45         line[len] = 0;
46
47         return line;
48 }
49
50 static void add_ref(const char *name, const unsigned char *sha1,
51                     int flag, int check_name, struct ref_array *refs,
52                     struct ref_entry **new_entry)
53 {
54         int len;
55         struct ref_entry *entry;
56
57         /* Allocate it and add it in.. */
58         len = strlen(name) + 1;
59         entry = xmalloc(sizeof(struct ref_entry) + len);
60         hashcpy(entry->sha1, sha1);
61         hashclr(entry->peeled);
62         if (check_name &&
63             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 ref_cache {
138         struct ref_cache *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 } *ref_cache;
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_packed_ref_cache(struct ref_cache *refs)
162 {
163         if (refs->did_packed)
164                 free_ref_array(&refs->packed);
165         refs->did_packed = 0;
166 }
167
168 static void clear_loose_ref_cache(struct ref_cache *refs)
169 {
170         if (refs->did_loose)
171                 free_ref_array(&refs->loose);
172         refs->did_loose = 0;
173 }
174
175 static struct ref_cache *create_ref_cache(const char *submodule)
176 {
177         int len;
178         struct ref_cache *refs;
179         if (!submodule)
180                 submodule = "";
181         len = strlen(submodule) + 1;
182         refs = xcalloc(1, sizeof(struct ref_cache) + len);
183         memcpy(refs->name, submodule, len);
184         return refs;
185 }
186
187 /*
188  * Return a pointer to a ref_cache for the specified submodule. For
189  * the main repository, use submodule==NULL. The returned structure
190  * will be allocated and initialized but not necessarily populated; it
191  * should not be freed.
192  */
193 static struct ref_cache *get_ref_cache(const char *submodule)
194 {
195         struct ref_cache *refs = ref_cache;
196         if (!submodule)
197                 submodule = "";
198         while (refs) {
199                 if (!strcmp(submodule, refs->name))
200                         return refs;
201                 refs = refs->next;
202         }
203
204         refs = create_ref_cache(submodule);
205         refs->next = ref_cache;
206         ref_cache = refs;
207         return refs;
208 }
209
210 void invalidate_ref_cache(const char *submodule)
211 {
212         struct ref_cache *refs = get_ref_cache(submodule);
213         clear_packed_ref_cache(refs);
214         clear_loose_ref_cache(refs);
215 }
216
217 static void read_packed_refs(FILE *f, struct ref_array *array)
218 {
219         struct ref_entry *last = NULL;
220         char refline[PATH_MAX];
221         int flag = REF_ISPACKED;
222
223         while (fgets(refline, sizeof(refline), f)) {
224                 unsigned char sha1[20];
225                 const char *name;
226                 static const char header[] = "# pack-refs with:";
227
228                 if (!strncmp(refline, header, sizeof(header)-1)) {
229                         const char *traits = refline + sizeof(header) - 1;
230                         if (strstr(traits, " peeled "))
231                                 flag |= REF_KNOWS_PEELED;
232                         /* perhaps other traits later as well */
233                         continue;
234                 }
235
236                 name = parse_ref_line(refline, sha1);
237                 if (name) {
238                         add_ref(name, sha1, flag, 1, array, &last);
239                         continue;
240                 }
241                 if (last &&
242                     refline[0] == '^' &&
243                     strlen(refline) == 42 &&
244                     refline[41] == '\n' &&
245                     !get_sha1_hex(refline + 1, sha1))
246                         hashcpy(last->peeled, sha1);
247         }
248         sort_ref_array(array);
249 }
250
251 void add_extra_ref(const char *name, const unsigned char *sha1, int flag)
252 {
253         add_ref(name, sha1, flag, 0, &extra_refs, NULL);
254 }
255
256 void clear_extra_refs(void)
257 {
258         free_ref_array(&extra_refs);
259 }
260
261 static struct ref_array *get_packed_refs(const char *submodule)
262 {
263         struct ref_cache *refs = get_ref_cache(submodule);
264
265         if (!refs->did_packed) {
266                 const char *packed_refs_file;
267                 FILE *f;
268
269                 if (submodule)
270                         packed_refs_file = git_path_submodule(submodule, "packed-refs");
271                 else
272                         packed_refs_file = git_path("packed-refs");
273                 f = fopen(packed_refs_file, "r");
274                 if (f) {
275                         read_packed_refs(f, &refs->packed);
276                         fclose(f);
277                 }
278                 refs->did_packed = 1;
279         }
280         return &refs->packed;
281 }
282
283 static void get_ref_dir(const char *submodule, const char *base,
284                         struct ref_array *array)
285 {
286         DIR *dir;
287         const char *path;
288
289         if (submodule)
290                 path = git_path_submodule(submodule, "%s", base);
291         else
292                 path = git_path("%s", base);
293
294
295         dir = opendir(path);
296
297         if (dir) {
298                 struct dirent *de;
299                 int baselen = strlen(base);
300                 char *ref = xmalloc(baselen + 257);
301
302                 memcpy(ref, base, baselen);
303                 if (baselen && base[baselen-1] != '/')
304                         ref[baselen++] = '/';
305
306                 while ((de = readdir(dir)) != NULL) {
307                         unsigned char sha1[20];
308                         struct stat st;
309                         int flag;
310                         int namelen;
311                         const char *refdir;
312
313                         if (de->d_name[0] == '.')
314                                 continue;
315                         namelen = strlen(de->d_name);
316                         if (namelen > 255)
317                                 continue;
318                         if (has_extension(de->d_name, ".lock"))
319                                 continue;
320                         memcpy(ref + baselen, de->d_name, namelen+1);
321                         refdir = submodule
322                                 ? git_path_submodule(submodule, "%s", ref)
323                                 : git_path("%s", ref);
324                         if (stat(refdir, &st) < 0)
325                                 continue;
326                         if (S_ISDIR(st.st_mode)) {
327                                 get_ref_dir(submodule, ref, array);
328                                 continue;
329                         }
330                         if (submodule) {
331                                 hashclr(sha1);
332                                 flag = 0;
333                                 if (resolve_gitlink_ref(submodule, ref, sha1) < 0) {
334                                         hashclr(sha1);
335                                         flag |= REF_ISBROKEN;
336                                 }
337                         } else if (!resolve_ref(ref, sha1, 1, &flag)) {
338                                 hashclr(sha1);
339                                 flag |= REF_ISBROKEN;
340                         }
341                         add_ref(ref, sha1, flag, 1, array, NULL);
342                 }
343                 free(ref);
344                 closedir(dir);
345         }
346 }
347
348 struct warn_if_dangling_data {
349         FILE *fp;
350         const char *refname;
351         const char *msg_fmt;
352 };
353
354 static int warn_if_dangling_symref(const char *refname, const unsigned char *sha1,
355                                    int flags, void *cb_data)
356 {
357         struct warn_if_dangling_data *d = cb_data;
358         const char *resolves_to;
359         unsigned char junk[20];
360
361         if (!(flags & REF_ISSYMREF))
362                 return 0;
363
364         resolves_to = resolve_ref(refname, junk, 0, NULL);
365         if (!resolves_to || strcmp(resolves_to, d->refname))
366                 return 0;
367
368         fprintf(d->fp, d->msg_fmt, refname);
369         return 0;
370 }
371
372 void warn_dangling_symref(FILE *fp, const char *msg_fmt, const char *refname)
373 {
374         struct warn_if_dangling_data data;
375
376         data.fp = fp;
377         data.refname = refname;
378         data.msg_fmt = msg_fmt;
379         for_each_rawref(warn_if_dangling_symref, &data);
380 }
381
382 static struct ref_array *get_loose_refs(const char *submodule)
383 {
384         struct ref_cache *refs = get_ref_cache(submodule);
385
386         if (!refs->did_loose) {
387                 get_ref_dir(submodule, "refs", &refs->loose);
388                 sort_ref_array(&refs->loose);
389                 refs->did_loose = 1;
390         }
391         return &refs->loose;
392 }
393
394 /* We allow "recursive" symbolic refs. Only within reason, though */
395 #define MAXDEPTH 5
396 #define MAXREFLEN (1024)
397
398 /*
399  * Called by resolve_gitlink_ref_recursive() after it failed to read
400  * from "name", which is "module/.git/<refname>". Find <refname> in
401  * the packed-refs file for the submodule.
402  */
403 static int resolve_gitlink_packed_ref(char *name, int pathlen, const char *refname, unsigned char *result)
404 {
405         int retval = -1;
406         struct ref_entry *ref;
407         struct ref_array *array;
408
409         /* being defensive: resolve_gitlink_ref() did this for us */
410         if (pathlen < 6 || memcmp(name + pathlen - 6, "/.git/", 6))
411                 die("Oops");
412         name[pathlen - 6] = '\0'; /* make it path to the submodule */
413         array = get_packed_refs(name);
414         ref = search_ref_array(array, refname);
415         if (ref != NULL) {
416                 memcpy(result, ref->sha1, 20);
417                 retval = 0;
418         }
419         return retval;
420 }
421
422 static int resolve_gitlink_ref_recursive(char *name, int pathlen, const char *refname, unsigned char *result, int recursion)
423 {
424         int fd, len = strlen(refname);
425         char buffer[128], *p;
426
427         if (recursion > MAXDEPTH || len > MAXREFLEN)
428                 return -1;
429         memcpy(name + pathlen, refname, len+1);
430         fd = open(name, O_RDONLY);
431         if (fd < 0)
432                 return resolve_gitlink_packed_ref(name, pathlen, refname, result);
433
434         len = read(fd, buffer, sizeof(buffer)-1);
435         close(fd);
436         if (len < 0)
437                 return -1;
438         while (len && isspace(buffer[len-1]))
439                 len--;
440         buffer[len] = 0;
441
442         /* Was it a detached head or an old-fashioned symlink? */
443         if (!get_sha1_hex(buffer, result))
444                 return 0;
445
446         /* Symref? */
447         if (strncmp(buffer, "ref:", 4))
448                 return -1;
449         p = buffer + 4;
450         while (isspace(*p))
451                 p++;
452
453         return resolve_gitlink_ref_recursive(name, pathlen, p, result, recursion+1);
454 }
455
456 int resolve_gitlink_ref(const char *path, const char *refname, unsigned char *result)
457 {
458         int len = strlen(path), retval;
459         char *gitdir;
460         const char *tmp;
461
462         while (len && path[len-1] == '/')
463                 len--;
464         if (!len)
465                 return -1;
466         gitdir = xmalloc(len + MAXREFLEN + 8);
467         memcpy(gitdir, path, len);
468         memcpy(gitdir + len, "/.git", 6);
469         len += 5;
470
471         tmp = read_gitfile(gitdir);
472         if (tmp) {
473                 free(gitdir);
474                 len = strlen(tmp);
475                 gitdir = xmalloc(len + MAXREFLEN + 3);
476                 memcpy(gitdir, tmp, len);
477         }
478         gitdir[len] = '/';
479         gitdir[++len] = '\0';
480         retval = resolve_gitlink_ref_recursive(gitdir, len, refname, result, 0);
481         free(gitdir);
482         return retval;
483 }
484
485 /*
486  * Try to read ref from the packed references.  On success, set sha1
487  * and return 0; otherwise, return -1.
488  */
489 static int get_packed_ref(const char *ref, unsigned char *sha1)
490 {
491         struct ref_array *packed = get_packed_refs(NULL);
492         struct ref_entry *entry = search_ref_array(packed, ref);
493         if (entry) {
494                 hashcpy(sha1, entry->sha1);
495                 return 0;
496         }
497         return -1;
498 }
499
500 const char *resolve_ref(const char *ref, unsigned char *sha1, int reading, int *flag)
501 {
502         int depth = MAXDEPTH;
503         ssize_t len;
504         char buffer[256];
505         static char ref_buffer[256];
506
507         if (flag)
508                 *flag = 0;
509
510         if (check_refname_format(ref, REFNAME_ALLOW_ONELEVEL))
511                 return NULL;
512
513         for (;;) {
514                 char path[PATH_MAX];
515                 struct stat st;
516                 char *buf;
517                 int fd;
518
519                 if (--depth < 0)
520                         return NULL;
521
522                 git_snpath(path, sizeof(path), "%s", ref);
523
524                 if (lstat(path, &st) < 0) {
525                         if (errno != ENOENT)
526                                 return NULL;
527                         /*
528                          * The loose reference file does not exist;
529                          * check for a packed reference.
530                          */
531                         if (!get_packed_ref(ref, sha1)) {
532                                 if (flag)
533                                         *flag |= REF_ISPACKED;
534                                 return ref;
535                         }
536                         /* The reference is not a packed reference, either. */
537                         if (reading) {
538                                 return NULL;
539                         } else {
540                                 hashclr(sha1);
541                                 return ref;
542                         }
543                 }
544
545                 /* Follow "normalized" - ie "refs/.." symlinks by hand */
546                 if (S_ISLNK(st.st_mode)) {
547                         len = readlink(path, buffer, sizeof(buffer)-1);
548                         if (len < 0)
549                                 return NULL;
550                         buffer[len] = 0;
551                         if (!prefixcmp(buffer, "refs/") &&
552                                         !check_refname_format(buffer, 0)) {
553                                 strcpy(ref_buffer, buffer);
554                                 ref = ref_buffer;
555                                 if (flag)
556                                         *flag |= REF_ISSYMREF;
557                                 continue;
558                         }
559                 }
560
561                 /* Is it a directory? */
562                 if (S_ISDIR(st.st_mode)) {
563                         errno = EISDIR;
564                         return NULL;
565                 }
566
567                 /*
568                  * Anything else, just open it and try to use it as
569                  * a ref
570                  */
571                 fd = open(path, O_RDONLY);
572                 if (fd < 0)
573                         return NULL;
574                 len = read_in_full(fd, buffer, sizeof(buffer)-1);
575                 close(fd);
576                 if (len < 0)
577                         return NULL;
578                 while (len && isspace(buffer[len-1]))
579                         len--;
580                 buffer[len] = '\0';
581
582                 /*
583                  * Is it a symbolic ref?
584                  */
585                 if (prefixcmp(buffer, "ref:"))
586                         break;
587                 if (flag)
588                         *flag |= REF_ISSYMREF;
589                 buf = buffer + 4;
590                 while (isspace(*buf))
591                         buf++;
592                 if (check_refname_format(buf, REFNAME_ALLOW_ONELEVEL)) {
593                         if (flag)
594                                 *flag |= REF_ISBROKEN;
595                         return NULL;
596                 }
597                 ref = strcpy(ref_buffer, buf);
598         }
599         /* Please note that FETCH_HEAD has a second line containing other data. */
600         if (get_sha1_hex(buffer, sha1) || (buffer[40] != '\0' && !isspace(buffer[40]))) {
601                 if (flag)
602                         *flag |= REF_ISBROKEN;
603                 return NULL;
604         }
605         return ref;
606 }
607
608 /* The argument to filter_refs */
609 struct ref_filter {
610         const char *pattern;
611         each_ref_fn *fn;
612         void *cb_data;
613 };
614
615 int read_ref(const char *ref, unsigned char *sha1)
616 {
617         if (resolve_ref(ref, sha1, 1, NULL))
618                 return 0;
619         return -1;
620 }
621
622 #define DO_FOR_EACH_INCLUDE_BROKEN 01
623 static int do_one_ref(const char *base, each_ref_fn fn, int trim,
624                       int flags, void *cb_data, struct ref_entry *entry)
625 {
626         if (prefixcmp(entry->name, base))
627                 return 0;
628
629         if (!(flags & DO_FOR_EACH_INCLUDE_BROKEN)) {
630                 if (entry->flag & REF_ISBROKEN)
631                         return 0; /* ignore broken refs e.g. dangling symref */
632                 if (!has_sha1_file(entry->sha1)) {
633                         error("%s does not point to a valid object!", entry->name);
634                         return 0;
635                 }
636         }
637         current_ref = entry;
638         return fn(entry->name + trim, entry->sha1, entry->flag, cb_data);
639 }
640
641 static int filter_refs(const char *ref, const unsigned char *sha, int flags,
642         void *data)
643 {
644         struct ref_filter *filter = (struct ref_filter *)data;
645         if (fnmatch(filter->pattern, ref, 0))
646                 return 0;
647         return filter->fn(ref, sha, flags, filter->cb_data);
648 }
649
650 int peel_ref(const char *ref, unsigned char *sha1)
651 {
652         int flag;
653         unsigned char base[20];
654         struct object *o;
655
656         if (current_ref && (current_ref->name == ref
657                 || !strcmp(current_ref->name, ref))) {
658                 if (current_ref->flag & REF_KNOWS_PEELED) {
659                         hashcpy(sha1, current_ref->peeled);
660                         return 0;
661                 }
662                 hashcpy(base, current_ref->sha1);
663                 goto fallback;
664         }
665
666         if (!resolve_ref(ref, base, 1, &flag))
667                 return -1;
668
669         if ((flag & REF_ISPACKED)) {
670                 struct ref_array *array = get_packed_refs(NULL);
671                 struct ref_entry *r = search_ref_array(array, ref);
672
673                 if (r != NULL && r->flag & REF_KNOWS_PEELED) {
674                         hashcpy(sha1, r->peeled);
675                         return 0;
676                 }
677         }
678
679 fallback:
680         o = parse_object(base);
681         if (o && o->type == OBJ_TAG) {
682                 o = deref_tag(o, ref, 0);
683                 if (o) {
684                         hashcpy(sha1, o->sha1);
685                         return 0;
686                 }
687         }
688         return -1;
689 }
690
691 static int do_for_each_ref(const char *submodule, const char *base, each_ref_fn fn,
692                            int trim, int flags, void *cb_data)
693 {
694         int retval = 0, i, p = 0, l = 0;
695         struct ref_array *packed = get_packed_refs(submodule);
696         struct ref_array *loose = get_loose_refs(submodule);
697
698         struct ref_array *extra = &extra_refs;
699
700         for (i = 0; i < extra->nr; i++)
701                 retval = do_one_ref(base, fn, trim, flags, cb_data, extra->refs[i]);
702
703         while (p < packed->nr && l < loose->nr) {
704                 struct ref_entry *entry;
705                 int cmp = strcmp(packed->refs[p]->name, loose->refs[l]->name);
706                 if (!cmp) {
707                         p++;
708                         continue;
709                 }
710                 if (cmp > 0) {
711                         entry = loose->refs[l++];
712                 } else {
713                         entry = packed->refs[p++];
714                 }
715                 retval = do_one_ref(base, fn, trim, flags, cb_data, entry);
716                 if (retval)
717                         goto end_each;
718         }
719
720         if (l < loose->nr) {
721                 p = l;
722                 packed = loose;
723         }
724
725         for (; p < packed->nr; p++) {
726                 retval = do_one_ref(base, fn, trim, flags, cb_data, packed->refs[p]);
727                 if (retval)
728                         goto end_each;
729         }
730
731 end_each:
732         current_ref = NULL;
733         return retval;
734 }
735
736
737 static int do_head_ref(const char *submodule, each_ref_fn fn, void *cb_data)
738 {
739         unsigned char sha1[20];
740         int flag;
741
742         if (submodule) {
743                 if (resolve_gitlink_ref(submodule, "HEAD", sha1) == 0)
744                         return fn("HEAD", sha1, 0, cb_data);
745
746                 return 0;
747         }
748
749         if (resolve_ref("HEAD", sha1, 1, &flag))
750                 return fn("HEAD", sha1, flag, cb_data);
751
752         return 0;
753 }
754
755 int head_ref(each_ref_fn fn, void *cb_data)
756 {
757         return do_head_ref(NULL, fn, cb_data);
758 }
759
760 int head_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
761 {
762         return do_head_ref(submodule, fn, cb_data);
763 }
764
765 int for_each_ref(each_ref_fn fn, void *cb_data)
766 {
767         return do_for_each_ref(NULL, "", fn, 0, 0, cb_data);
768 }
769
770 int for_each_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
771 {
772         return do_for_each_ref(submodule, "", fn, 0, 0, cb_data);
773 }
774
775 int for_each_ref_in(const char *prefix, each_ref_fn fn, void *cb_data)
776 {
777         return do_for_each_ref(NULL, prefix, fn, strlen(prefix), 0, cb_data);
778 }
779
780 int for_each_ref_in_submodule(const char *submodule, const char *prefix,
781                 each_ref_fn fn, void *cb_data)
782 {
783         return do_for_each_ref(submodule, prefix, fn, strlen(prefix), 0, cb_data);
784 }
785
786 int for_each_tag_ref(each_ref_fn fn, void *cb_data)
787 {
788         return for_each_ref_in("refs/tags/", fn, cb_data);
789 }
790
791 int for_each_tag_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
792 {
793         return for_each_ref_in_submodule(submodule, "refs/tags/", fn, cb_data);
794 }
795
796 int for_each_branch_ref(each_ref_fn fn, void *cb_data)
797 {
798         return for_each_ref_in("refs/heads/", fn, cb_data);
799 }
800
801 int for_each_branch_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
802 {
803         return for_each_ref_in_submodule(submodule, "refs/heads/", fn, cb_data);
804 }
805
806 int for_each_remote_ref(each_ref_fn fn, void *cb_data)
807 {
808         return for_each_ref_in("refs/remotes/", fn, cb_data);
809 }
810
811 int for_each_remote_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
812 {
813         return for_each_ref_in_submodule(submodule, "refs/remotes/", fn, cb_data);
814 }
815
816 int for_each_replace_ref(each_ref_fn fn, void *cb_data)
817 {
818         return do_for_each_ref(NULL, "refs/replace/", fn, 13, 0, cb_data);
819 }
820
821 int head_ref_namespaced(each_ref_fn fn, void *cb_data)
822 {
823         struct strbuf buf = STRBUF_INIT;
824         int ret = 0;
825         unsigned char sha1[20];
826         int flag;
827
828         strbuf_addf(&buf, "%sHEAD", get_git_namespace());
829         if (resolve_ref(buf.buf, sha1, 1, &flag))
830                 ret = fn(buf.buf, sha1, flag, cb_data);
831         strbuf_release(&buf);
832
833         return ret;
834 }
835
836 int for_each_namespaced_ref(each_ref_fn fn, void *cb_data)
837 {
838         struct strbuf buf = STRBUF_INIT;
839         int ret;
840         strbuf_addf(&buf, "%srefs/", get_git_namespace());
841         ret = do_for_each_ref(NULL, buf.buf, fn, 0, 0, cb_data);
842         strbuf_release(&buf);
843         return ret;
844 }
845
846 int for_each_glob_ref_in(each_ref_fn fn, const char *pattern,
847         const char *prefix, void *cb_data)
848 {
849         struct strbuf real_pattern = STRBUF_INIT;
850         struct ref_filter filter;
851         int ret;
852
853         if (!prefix && prefixcmp(pattern, "refs/"))
854                 strbuf_addstr(&real_pattern, "refs/");
855         else if (prefix)
856                 strbuf_addstr(&real_pattern, prefix);
857         strbuf_addstr(&real_pattern, pattern);
858
859         if (!has_glob_specials(pattern)) {
860                 /* Append implied '/' '*' if not present. */
861                 if (real_pattern.buf[real_pattern.len - 1] != '/')
862                         strbuf_addch(&real_pattern, '/');
863                 /* No need to check for '*', there is none. */
864                 strbuf_addch(&real_pattern, '*');
865         }
866
867         filter.pattern = real_pattern.buf;
868         filter.fn = fn;
869         filter.cb_data = cb_data;
870         ret = for_each_ref(filter_refs, &filter);
871
872         strbuf_release(&real_pattern);
873         return ret;
874 }
875
876 int for_each_glob_ref(each_ref_fn fn, const char *pattern, void *cb_data)
877 {
878         return for_each_glob_ref_in(fn, pattern, NULL, cb_data);
879 }
880
881 int for_each_rawref(each_ref_fn fn, void *cb_data)
882 {
883         return do_for_each_ref(NULL, "", fn, 0,
884                                DO_FOR_EACH_INCLUDE_BROKEN, cb_data);
885 }
886
887 /*
888  * Make sure "ref" is something reasonable to have under ".git/refs/";
889  * We do not like it if:
890  *
891  * - any path component of it begins with ".", or
892  * - it has double dots "..", or
893  * - it has ASCII control character, "~", "^", ":" or SP, anywhere, or
894  * - it ends with a "/".
895  * - it ends with ".lock"
896  * - it contains a "\" (backslash)
897  */
898
899 /* Return true iff ch is not allowed in reference names. */
900 static inline int bad_ref_char(int ch)
901 {
902         if (((unsigned) ch) <= ' ' || ch == 0x7f ||
903             ch == '~' || ch == '^' || ch == ':' || ch == '\\')
904                 return 1;
905         /* 2.13 Pattern Matching Notation */
906         if (ch == '*' || ch == '?' || ch == '[') /* Unsupported */
907                 return 1;
908         return 0;
909 }
910
911 /*
912  * Try to read one refname component from the front of ref.  Return
913  * the length of the component found, or -1 if the component is not
914  * legal.
915  */
916 static int check_refname_component(const char *ref, int flags)
917 {
918         const char *cp;
919         char last = '\0';
920
921         for (cp = ref; ; cp++) {
922                 char ch = *cp;
923                 if (ch == '\0' || ch == '/')
924                         break;
925                 if (bad_ref_char(ch))
926                         return -1; /* Illegal character in refname. */
927                 if (last == '.' && ch == '.')
928                         return -1; /* Refname contains "..". */
929                 if (last == '@' && ch == '{')
930                         return -1; /* Refname contains "@{". */
931                 last = ch;
932         }
933         if (cp == ref)
934                 return -1; /* Component has zero length. */
935         if (ref[0] == '.') {
936                 if (!(flags & REFNAME_DOT_COMPONENT))
937                         return -1; /* Component starts with '.'. */
938                 /*
939                  * Even if leading dots are allowed, don't allow "."
940                  * as a component (".." is prevented by a rule above).
941                  */
942                 if (ref[1] == '\0')
943                         return -1; /* Component equals ".". */
944         }
945         if (cp - ref >= 5 && !memcmp(cp - 5, ".lock", 5))
946                 return -1; /* Refname ends with ".lock". */
947         return cp - ref;
948 }
949
950 int check_refname_format(const char *ref, int flags)
951 {
952         int component_len, component_count = 0;
953
954         while (1) {
955                 /* We are at the start of a path component. */
956                 component_len = check_refname_component(ref, flags);
957                 if (component_len < 0) {
958                         if ((flags & REFNAME_REFSPEC_PATTERN) &&
959                                         ref[0] == '*' &&
960                                         (ref[1] == '\0' || ref[1] == '/')) {
961                                 /* Accept one wildcard as a full refname component. */
962                                 flags &= ~REFNAME_REFSPEC_PATTERN;
963                                 component_len = 1;
964                         } else {
965                                 return -1;
966                         }
967                 }
968                 component_count++;
969                 if (ref[component_len] == '\0')
970                         break;
971                 /* Skip to next component. */
972                 ref += component_len + 1;
973         }
974
975         if (ref[component_len - 1] == '.')
976                 return -1; /* Refname ends with '.'. */
977         if (!(flags & REFNAME_ALLOW_ONELEVEL) && component_count < 2)
978                 return -1; /* Refname has only one component. */
979         return 0;
980 }
981
982 const char *prettify_refname(const char *name)
983 {
984         return name + (
985                 !prefixcmp(name, "refs/heads/") ? 11 :
986                 !prefixcmp(name, "refs/tags/") ? 10 :
987                 !prefixcmp(name, "refs/remotes/") ? 13 :
988                 0);
989 }
990
991 const char *ref_rev_parse_rules[] = {
992         "%.*s",
993         "refs/%.*s",
994         "refs/tags/%.*s",
995         "refs/heads/%.*s",
996         "refs/remotes/%.*s",
997         "refs/remotes/%.*s/HEAD",
998         NULL
999 };
1000
1001 const char *ref_fetch_rules[] = {
1002         "%.*s",
1003         "refs/%.*s",
1004         "refs/heads/%.*s",
1005         NULL
1006 };
1007
1008 int refname_match(const char *abbrev_name, const char *full_name, const char **rules)
1009 {
1010         const char **p;
1011         const int abbrev_name_len = strlen(abbrev_name);
1012
1013         for (p = rules; *p; p++) {
1014                 if (!strcmp(full_name, mkpath(*p, abbrev_name_len, abbrev_name))) {
1015                         return 1;
1016                 }
1017         }
1018
1019         return 0;
1020 }
1021
1022 static struct ref_lock *verify_lock(struct ref_lock *lock,
1023         const unsigned char *old_sha1, int mustexist)
1024 {
1025         if (!resolve_ref(lock->ref_name, lock->old_sha1, mustexist, NULL)) {
1026                 error("Can't verify ref %s", lock->ref_name);
1027                 unlock_ref(lock);
1028                 return NULL;
1029         }
1030         if (hashcmp(lock->old_sha1, old_sha1)) {
1031                 error("Ref %s is at %s but expected %s", lock->ref_name,
1032                         sha1_to_hex(lock->old_sha1), sha1_to_hex(old_sha1));
1033                 unlock_ref(lock);
1034                 return NULL;
1035         }
1036         return lock;
1037 }
1038
1039 static int remove_empty_directories(const char *file)
1040 {
1041         /* we want to create a file but there is a directory there;
1042          * if that is an empty directory (or a directory that contains
1043          * only empty directories), remove them.
1044          */
1045         struct strbuf path;
1046         int result;
1047
1048         strbuf_init(&path, 20);
1049         strbuf_addstr(&path, file);
1050
1051         result = remove_dir_recursively(&path, REMOVE_DIR_EMPTY_ONLY);
1052
1053         strbuf_release(&path);
1054
1055         return result;
1056 }
1057
1058 static int is_refname_available(const char *ref, const char *oldref,
1059                                 struct ref_array *array, int quiet)
1060 {
1061         int i, namlen = strlen(ref); /* e.g. 'foo/bar' */
1062         for (i = 0; i < array->nr; i++ ) {
1063                 struct ref_entry *entry = array->refs[i];
1064                 /* entry->name could be 'foo' or 'foo/bar/baz' */
1065                 if (!oldref || strcmp(oldref, entry->name)) {
1066                         int len = strlen(entry->name);
1067                         int cmplen = (namlen < len) ? namlen : len;
1068                         const char *lead = (namlen < len) ? entry->name : ref;
1069                         if (!strncmp(ref, entry->name, cmplen) &&
1070                             lead[cmplen] == '/') {
1071                                 if (!quiet)
1072                                         error("'%s' exists; cannot create '%s'",
1073                                               entry->name, ref);
1074                                 return 0;
1075                         }
1076                 }
1077         }
1078         return 1;
1079 }
1080
1081 /*
1082  * *string and *len will only be substituted, and *string returned (for
1083  * later free()ing) if the string passed in is a magic short-hand form
1084  * to name a branch.
1085  */
1086 static char *substitute_branch_name(const char **string, int *len)
1087 {
1088         struct strbuf buf = STRBUF_INIT;
1089         int ret = interpret_branch_name(*string, &buf);
1090
1091         if (ret == *len) {
1092                 size_t size;
1093                 *string = strbuf_detach(&buf, &size);
1094                 *len = size;
1095                 return (char *)*string;
1096         }
1097
1098         return NULL;
1099 }
1100
1101 int dwim_ref(const char *str, int len, unsigned char *sha1, char **ref)
1102 {
1103         char *last_branch = substitute_branch_name(&str, &len);
1104         const char **p, *r;
1105         int refs_found = 0;
1106
1107         *ref = NULL;
1108         for (p = ref_rev_parse_rules; *p; p++) {
1109                 char fullref[PATH_MAX];
1110                 unsigned char sha1_from_ref[20];
1111                 unsigned char *this_result;
1112                 int flag;
1113
1114                 this_result = refs_found ? sha1_from_ref : sha1;
1115                 mksnpath(fullref, sizeof(fullref), *p, len, str);
1116                 r = resolve_ref(fullref, this_result, 1, &flag);
1117                 if (r) {
1118                         if (!refs_found++)
1119                                 *ref = xstrdup(r);
1120                         if (!warn_ambiguous_refs)
1121                                 break;
1122                 } else if ((flag & REF_ISSYMREF) && strcmp(fullref, "HEAD")) {
1123                         warning("ignoring dangling symref %s.", fullref);
1124                 } else if ((flag & REF_ISBROKEN) && strchr(fullref, '/')) {
1125                         warning("ignoring broken ref %s.", fullref);
1126                 }
1127         }
1128         free(last_branch);
1129         return refs_found;
1130 }
1131
1132 int dwim_log(const char *str, int len, unsigned char *sha1, char **log)
1133 {
1134         char *last_branch = substitute_branch_name(&str, &len);
1135         const char **p;
1136         int logs_found = 0;
1137
1138         *log = NULL;
1139         for (p = ref_rev_parse_rules; *p; p++) {
1140                 struct stat st;
1141                 unsigned char hash[20];
1142                 char path[PATH_MAX];
1143                 const char *ref, *it;
1144
1145                 mksnpath(path, sizeof(path), *p, len, str);
1146                 ref = resolve_ref(path, hash, 1, NULL);
1147                 if (!ref)
1148                         continue;
1149                 if (!stat(git_path("logs/%s", path), &st) &&
1150                     S_ISREG(st.st_mode))
1151                         it = path;
1152                 else if (strcmp(ref, path) &&
1153                          !stat(git_path("logs/%s", ref), &st) &&
1154                          S_ISREG(st.st_mode))
1155                         it = ref;
1156                 else
1157                         continue;
1158                 if (!logs_found++) {
1159                         *log = xstrdup(it);
1160                         hashcpy(sha1, hash);
1161                 }
1162                 if (!warn_ambiguous_refs)
1163                         break;
1164         }
1165         free(last_branch);
1166         return logs_found;
1167 }
1168
1169 static struct ref_lock *lock_ref_sha1_basic(const char *ref, const unsigned char *old_sha1, int flags, int *type_p)
1170 {
1171         char *ref_file;
1172         const char *orig_ref = ref;
1173         struct ref_lock *lock;
1174         int last_errno = 0;
1175         int type, lflags;
1176         int mustexist = (old_sha1 && !is_null_sha1(old_sha1));
1177         int missing = 0;
1178
1179         lock = xcalloc(1, sizeof(struct ref_lock));
1180         lock->lock_fd = -1;
1181
1182         ref = resolve_ref(ref, lock->old_sha1, mustexist, &type);
1183         if (!ref && errno == EISDIR) {
1184                 /* we are trying to lock foo but we used to
1185                  * have foo/bar which now does not exist;
1186                  * it is normal for the empty directory 'foo'
1187                  * to remain.
1188                  */
1189                 ref_file = git_path("%s", orig_ref);
1190                 if (remove_empty_directories(ref_file)) {
1191                         last_errno = errno;
1192                         error("there are still refs under '%s'", orig_ref);
1193                         goto error_return;
1194                 }
1195                 ref = resolve_ref(orig_ref, lock->old_sha1, mustexist, &type);
1196         }
1197         if (type_p)
1198             *type_p = type;
1199         if (!ref) {
1200                 last_errno = errno;
1201                 error("unable to resolve reference %s: %s",
1202                         orig_ref, strerror(errno));
1203                 goto error_return;
1204         }
1205         missing = is_null_sha1(lock->old_sha1);
1206         /* When the ref did not exist and we are creating it,
1207          * make sure there is no existing ref that is packed
1208          * whose name begins with our refname, nor a ref whose
1209          * name is a proper prefix of our refname.
1210          */
1211         if (missing &&
1212              !is_refname_available(ref, NULL, get_packed_refs(NULL), 0)) {
1213                 last_errno = ENOTDIR;
1214                 goto error_return;
1215         }
1216
1217         lock->lk = xcalloc(1, sizeof(struct lock_file));
1218
1219         lflags = LOCK_DIE_ON_ERROR;
1220         if (flags & REF_NODEREF) {
1221                 ref = orig_ref;
1222                 lflags |= LOCK_NODEREF;
1223         }
1224         lock->ref_name = xstrdup(ref);
1225         lock->orig_ref_name = xstrdup(orig_ref);
1226         ref_file = git_path("%s", ref);
1227         if (missing)
1228                 lock->force_write = 1;
1229         if ((flags & REF_NODEREF) && (type & REF_ISSYMREF))
1230                 lock->force_write = 1;
1231
1232         if (safe_create_leading_directories(ref_file)) {
1233                 last_errno = errno;
1234                 error("unable to create directory for %s", ref_file);
1235                 goto error_return;
1236         }
1237
1238         lock->lock_fd = hold_lock_file_for_update(lock->lk, ref_file, lflags);
1239         return old_sha1 ? verify_lock(lock, old_sha1, mustexist) : lock;
1240
1241  error_return:
1242         unlock_ref(lock);
1243         errno = last_errno;
1244         return NULL;
1245 }
1246
1247 struct ref_lock *lock_ref_sha1(const char *ref, const unsigned char *old_sha1)
1248 {
1249         char refpath[PATH_MAX];
1250         if (check_refname_format(ref, 0))
1251                 return NULL;
1252         strcpy(refpath, mkpath("refs/%s", ref));
1253         return lock_ref_sha1_basic(refpath, old_sha1, 0, NULL);
1254 }
1255
1256 struct ref_lock *lock_any_ref_for_update(const char *ref, const unsigned char *old_sha1, int flags)
1257 {
1258         if (check_refname_format(ref, REFNAME_ALLOW_ONELEVEL))
1259                 return NULL;
1260         return lock_ref_sha1_basic(ref, old_sha1, flags, NULL);
1261 }
1262
1263 static struct lock_file packlock;
1264
1265 static int repack_without_ref(const char *refname)
1266 {
1267         struct ref_array *packed;
1268         struct ref_entry *ref;
1269         int fd, i;
1270
1271         packed = get_packed_refs(NULL);
1272         ref = search_ref_array(packed, refname);
1273         if (ref == NULL)
1274                 return 0;
1275         fd = hold_lock_file_for_update(&packlock, git_path("packed-refs"), 0);
1276         if (fd < 0) {
1277                 unable_to_lock_error(git_path("packed-refs"), errno);
1278                 return error("cannot delete '%s' from packed refs", refname);
1279         }
1280
1281         for (i = 0; i < packed->nr; i++) {
1282                 char line[PATH_MAX + 100];
1283                 int len;
1284
1285                 ref = packed->refs[i];
1286
1287                 if (!strcmp(refname, ref->name))
1288                         continue;
1289                 len = snprintf(line, sizeof(line), "%s %s\n",
1290                                sha1_to_hex(ref->sha1), ref->name);
1291                 /* this should not happen but just being defensive */
1292                 if (len > sizeof(line))
1293                         die("too long a refname '%s'", ref->name);
1294                 write_or_die(fd, line, len);
1295         }
1296         return commit_lock_file(&packlock);
1297 }
1298
1299 int delete_ref(const char *refname, const unsigned char *sha1, int delopt)
1300 {
1301         struct ref_lock *lock;
1302         int err, i = 0, ret = 0, flag = 0;
1303
1304         lock = lock_ref_sha1_basic(refname, sha1, 0, &flag);
1305         if (!lock)
1306                 return 1;
1307         if (!(flag & REF_ISPACKED) || flag & REF_ISSYMREF) {
1308                 /* loose */
1309                 const char *path;
1310
1311                 if (!(delopt & REF_NODEREF)) {
1312                         i = strlen(lock->lk->filename) - 5; /* .lock */
1313                         lock->lk->filename[i] = 0;
1314                         path = lock->lk->filename;
1315                 } else {
1316                         path = git_path("%s", refname);
1317                 }
1318                 err = unlink_or_warn(path);
1319                 if (err && errno != ENOENT)
1320                         ret = 1;
1321
1322                 if (!(delopt & REF_NODEREF))
1323                         lock->lk->filename[i] = '.';
1324         }
1325         /* removing the loose one could have resurrected an earlier
1326          * packed one.  Also, if it was not loose we need to repack
1327          * without it.
1328          */
1329         ret |= repack_without_ref(refname);
1330
1331         unlink_or_warn(git_path("logs/%s", lock->ref_name));
1332         invalidate_ref_cache(NULL);
1333         unlock_ref(lock);
1334         return ret;
1335 }
1336
1337 /*
1338  * People using contrib's git-new-workdir have .git/logs/refs ->
1339  * /some/other/path/.git/logs/refs, and that may live on another device.
1340  *
1341  * IOW, to avoid cross device rename errors, the temporary renamed log must
1342  * live into logs/refs.
1343  */
1344 #define TMP_RENAMED_LOG  "logs/refs/.tmp-renamed-log"
1345
1346 int rename_ref(const char *oldref, const char *newref, const char *logmsg)
1347 {
1348         unsigned char sha1[20], orig_sha1[20];
1349         int flag = 0, logmoved = 0;
1350         struct ref_lock *lock;
1351         struct stat loginfo;
1352         int log = !lstat(git_path("logs/%s", oldref), &loginfo);
1353         const char *symref = NULL;
1354
1355         if (log && S_ISLNK(loginfo.st_mode))
1356                 return error("reflog for %s is a symlink", oldref);
1357
1358         symref = resolve_ref(oldref, orig_sha1, 1, &flag);
1359         if (flag & REF_ISSYMREF)
1360                 return error("refname %s is a symbolic ref, renaming it is not supported",
1361                         oldref);
1362         if (!symref)
1363                 return error("refname %s not found", oldref);
1364
1365         if (!is_refname_available(newref, oldref, get_packed_refs(NULL), 0))
1366                 return 1;
1367
1368         if (!is_refname_available(newref, oldref, get_loose_refs(NULL), 0))
1369                 return 1;
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         clear_loose_ref_cache(get_ref_cache(NULL));
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(const 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 }