git-p4: document and test --import-local
[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 (read_ref_full(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_full(const char *ref, unsigned char *sha1, int reading, int *flags)
616 {
617         if (resolve_ref(ref, sha1, reading, flags))
618                 return 0;
619         return -1;
620 }
621
622 int read_ref(const char *ref, unsigned char *sha1)
623 {
624         return read_ref_full(ref, sha1, 1, NULL);
625 }
626
627 #define DO_FOR_EACH_INCLUDE_BROKEN 01
628 static int do_one_ref(const char *base, each_ref_fn fn, int trim,
629                       int flags, void *cb_data, struct ref_entry *entry)
630 {
631         if (prefixcmp(entry->name, base))
632                 return 0;
633
634         if (!(flags & DO_FOR_EACH_INCLUDE_BROKEN)) {
635                 if (entry->flag & REF_ISBROKEN)
636                         return 0; /* ignore broken refs e.g. dangling symref */
637                 if (!has_sha1_file(entry->sha1)) {
638                         error("%s does not point to a valid object!", entry->name);
639                         return 0;
640                 }
641         }
642         current_ref = entry;
643         return fn(entry->name + trim, entry->sha1, entry->flag, cb_data);
644 }
645
646 static int filter_refs(const char *ref, const unsigned char *sha, int flags,
647         void *data)
648 {
649         struct ref_filter *filter = (struct ref_filter *)data;
650         if (fnmatch(filter->pattern, ref, 0))
651                 return 0;
652         return filter->fn(ref, sha, flags, filter->cb_data);
653 }
654
655 int peel_ref(const char *ref, unsigned char *sha1)
656 {
657         int flag;
658         unsigned char base[20];
659         struct object *o;
660
661         if (current_ref && (current_ref->name == ref
662                 || !strcmp(current_ref->name, ref))) {
663                 if (current_ref->flag & REF_KNOWS_PEELED) {
664                         hashcpy(sha1, current_ref->peeled);
665                         return 0;
666                 }
667                 hashcpy(base, current_ref->sha1);
668                 goto fallback;
669         }
670
671         if (read_ref_full(ref, base, 1, &flag))
672                 return -1;
673
674         if ((flag & REF_ISPACKED)) {
675                 struct ref_array *array = get_packed_refs(NULL);
676                 struct ref_entry *r = search_ref_array(array, ref);
677
678                 if (r != NULL && r->flag & REF_KNOWS_PEELED) {
679                         hashcpy(sha1, r->peeled);
680                         return 0;
681                 }
682         }
683
684 fallback:
685         o = parse_object(base);
686         if (o && o->type == OBJ_TAG) {
687                 o = deref_tag(o, ref, 0);
688                 if (o) {
689                         hashcpy(sha1, o->sha1);
690                         return 0;
691                 }
692         }
693         return -1;
694 }
695
696 static int do_for_each_ref(const char *submodule, const char *base, each_ref_fn fn,
697                            int trim, int flags, void *cb_data)
698 {
699         int retval = 0, i, p = 0, l = 0;
700         struct ref_array *packed = get_packed_refs(submodule);
701         struct ref_array *loose = get_loose_refs(submodule);
702
703         struct ref_array *extra = &extra_refs;
704
705         for (i = 0; i < extra->nr; i++)
706                 retval = do_one_ref(base, fn, trim, flags, cb_data, extra->refs[i]);
707
708         while (p < packed->nr && l < loose->nr) {
709                 struct ref_entry *entry;
710                 int cmp = strcmp(packed->refs[p]->name, loose->refs[l]->name);
711                 if (!cmp) {
712                         p++;
713                         continue;
714                 }
715                 if (cmp > 0) {
716                         entry = loose->refs[l++];
717                 } else {
718                         entry = packed->refs[p++];
719                 }
720                 retval = do_one_ref(base, fn, trim, flags, cb_data, entry);
721                 if (retval)
722                         goto end_each;
723         }
724
725         if (l < loose->nr) {
726                 p = l;
727                 packed = loose;
728         }
729
730         for (; p < packed->nr; p++) {
731                 retval = do_one_ref(base, fn, trim, flags, cb_data, packed->refs[p]);
732                 if (retval)
733                         goto end_each;
734         }
735
736 end_each:
737         current_ref = NULL;
738         return retval;
739 }
740
741
742 static int do_head_ref(const char *submodule, each_ref_fn fn, void *cb_data)
743 {
744         unsigned char sha1[20];
745         int flag;
746
747         if (submodule) {
748                 if (resolve_gitlink_ref(submodule, "HEAD", sha1) == 0)
749                         return fn("HEAD", sha1, 0, cb_data);
750
751                 return 0;
752         }
753
754         if (!read_ref_full("HEAD", sha1, 1, &flag))
755                 return fn("HEAD", sha1, flag, cb_data);
756
757         return 0;
758 }
759
760 int head_ref(each_ref_fn fn, void *cb_data)
761 {
762         return do_head_ref(NULL, fn, cb_data);
763 }
764
765 int head_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
766 {
767         return do_head_ref(submodule, fn, cb_data);
768 }
769
770 int for_each_ref(each_ref_fn fn, void *cb_data)
771 {
772         return do_for_each_ref(NULL, "", fn, 0, 0, cb_data);
773 }
774
775 int for_each_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
776 {
777         return do_for_each_ref(submodule, "", fn, 0, 0, cb_data);
778 }
779
780 int for_each_ref_in(const char *prefix, each_ref_fn fn, void *cb_data)
781 {
782         return do_for_each_ref(NULL, prefix, fn, strlen(prefix), 0, cb_data);
783 }
784
785 int for_each_ref_in_submodule(const char *submodule, const char *prefix,
786                 each_ref_fn fn, void *cb_data)
787 {
788         return do_for_each_ref(submodule, prefix, fn, strlen(prefix), 0, cb_data);
789 }
790
791 int for_each_tag_ref(each_ref_fn fn, void *cb_data)
792 {
793         return for_each_ref_in("refs/tags/", fn, cb_data);
794 }
795
796 int for_each_tag_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
797 {
798         return for_each_ref_in_submodule(submodule, "refs/tags/", fn, cb_data);
799 }
800
801 int for_each_branch_ref(each_ref_fn fn, void *cb_data)
802 {
803         return for_each_ref_in("refs/heads/", fn, cb_data);
804 }
805
806 int for_each_branch_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
807 {
808         return for_each_ref_in_submodule(submodule, "refs/heads/", fn, cb_data);
809 }
810
811 int for_each_remote_ref(each_ref_fn fn, void *cb_data)
812 {
813         return for_each_ref_in("refs/remotes/", fn, cb_data);
814 }
815
816 int for_each_remote_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
817 {
818         return for_each_ref_in_submodule(submodule, "refs/remotes/", fn, cb_data);
819 }
820
821 int for_each_replace_ref(each_ref_fn fn, void *cb_data)
822 {
823         return do_for_each_ref(NULL, "refs/replace/", fn, 13, 0, cb_data);
824 }
825
826 int head_ref_namespaced(each_ref_fn fn, void *cb_data)
827 {
828         struct strbuf buf = STRBUF_INIT;
829         int ret = 0;
830         unsigned char sha1[20];
831         int flag;
832
833         strbuf_addf(&buf, "%sHEAD", get_git_namespace());
834         if (!read_ref_full(buf.buf, sha1, 1, &flag))
835                 ret = fn(buf.buf, sha1, flag, cb_data);
836         strbuf_release(&buf);
837
838         return ret;
839 }
840
841 int for_each_namespaced_ref(each_ref_fn fn, void *cb_data)
842 {
843         struct strbuf buf = STRBUF_INIT;
844         int ret;
845         strbuf_addf(&buf, "%srefs/", get_git_namespace());
846         ret = do_for_each_ref(NULL, buf.buf, fn, 0, 0, cb_data);
847         strbuf_release(&buf);
848         return ret;
849 }
850
851 int for_each_glob_ref_in(each_ref_fn fn, const char *pattern,
852         const char *prefix, void *cb_data)
853 {
854         struct strbuf real_pattern = STRBUF_INIT;
855         struct ref_filter filter;
856         int ret;
857
858         if (!prefix && prefixcmp(pattern, "refs/"))
859                 strbuf_addstr(&real_pattern, "refs/");
860         else if (prefix)
861                 strbuf_addstr(&real_pattern, prefix);
862         strbuf_addstr(&real_pattern, pattern);
863
864         if (!has_glob_specials(pattern)) {
865                 /* Append implied '/' '*' if not present. */
866                 if (real_pattern.buf[real_pattern.len - 1] != '/')
867                         strbuf_addch(&real_pattern, '/');
868                 /* No need to check for '*', there is none. */
869                 strbuf_addch(&real_pattern, '*');
870         }
871
872         filter.pattern = real_pattern.buf;
873         filter.fn = fn;
874         filter.cb_data = cb_data;
875         ret = for_each_ref(filter_refs, &filter);
876
877         strbuf_release(&real_pattern);
878         return ret;
879 }
880
881 int for_each_glob_ref(each_ref_fn fn, const char *pattern, void *cb_data)
882 {
883         return for_each_glob_ref_in(fn, pattern, NULL, cb_data);
884 }
885
886 int for_each_rawref(each_ref_fn fn, void *cb_data)
887 {
888         return do_for_each_ref(NULL, "", fn, 0,
889                                DO_FOR_EACH_INCLUDE_BROKEN, cb_data);
890 }
891
892 /*
893  * Make sure "ref" is something reasonable to have under ".git/refs/";
894  * We do not like it if:
895  *
896  * - any path component of it begins with ".", or
897  * - it has double dots "..", or
898  * - it has ASCII control character, "~", "^", ":" or SP, anywhere, or
899  * - it ends with a "/".
900  * - it ends with ".lock"
901  * - it contains a "\" (backslash)
902  */
903
904 /* Return true iff ch is not allowed in reference names. */
905 static inline int bad_ref_char(int ch)
906 {
907         if (((unsigned) ch) <= ' ' || ch == 0x7f ||
908             ch == '~' || ch == '^' || ch == ':' || ch == '\\')
909                 return 1;
910         /* 2.13 Pattern Matching Notation */
911         if (ch == '*' || ch == '?' || ch == '[') /* Unsupported */
912                 return 1;
913         return 0;
914 }
915
916 /*
917  * Try to read one refname component from the front of ref.  Return
918  * the length of the component found, or -1 if the component is not
919  * legal.
920  */
921 static int check_refname_component(const char *ref, int flags)
922 {
923         const char *cp;
924         char last = '\0';
925
926         for (cp = ref; ; cp++) {
927                 char ch = *cp;
928                 if (ch == '\0' || ch == '/')
929                         break;
930                 if (bad_ref_char(ch))
931                         return -1; /* Illegal character in refname. */
932                 if (last == '.' && ch == '.')
933                         return -1; /* Refname contains "..". */
934                 if (last == '@' && ch == '{')
935                         return -1; /* Refname contains "@{". */
936                 last = ch;
937         }
938         if (cp == ref)
939                 return -1; /* Component has zero length. */
940         if (ref[0] == '.') {
941                 if (!(flags & REFNAME_DOT_COMPONENT))
942                         return -1; /* Component starts with '.'. */
943                 /*
944                  * Even if leading dots are allowed, don't allow "."
945                  * as a component (".." is prevented by a rule above).
946                  */
947                 if (ref[1] == '\0')
948                         return -1; /* Component equals ".". */
949         }
950         if (cp - ref >= 5 && !memcmp(cp - 5, ".lock", 5))
951                 return -1; /* Refname ends with ".lock". */
952         return cp - ref;
953 }
954
955 int check_refname_format(const char *ref, int flags)
956 {
957         int component_len, component_count = 0;
958
959         while (1) {
960                 /* We are at the start of a path component. */
961                 component_len = check_refname_component(ref, flags);
962                 if (component_len < 0) {
963                         if ((flags & REFNAME_REFSPEC_PATTERN) &&
964                                         ref[0] == '*' &&
965                                         (ref[1] == '\0' || ref[1] == '/')) {
966                                 /* Accept one wildcard as a full refname component. */
967                                 flags &= ~REFNAME_REFSPEC_PATTERN;
968                                 component_len = 1;
969                         } else {
970                                 return -1;
971                         }
972                 }
973                 component_count++;
974                 if (ref[component_len] == '\0')
975                         break;
976                 /* Skip to next component. */
977                 ref += component_len + 1;
978         }
979
980         if (ref[component_len - 1] == '.')
981                 return -1; /* Refname ends with '.'. */
982         if (!(flags & REFNAME_ALLOW_ONELEVEL) && component_count < 2)
983                 return -1; /* Refname has only one component. */
984         return 0;
985 }
986
987 const char *prettify_refname(const char *name)
988 {
989         return name + (
990                 !prefixcmp(name, "refs/heads/") ? 11 :
991                 !prefixcmp(name, "refs/tags/") ? 10 :
992                 !prefixcmp(name, "refs/remotes/") ? 13 :
993                 0);
994 }
995
996 const char *ref_rev_parse_rules[] = {
997         "%.*s",
998         "refs/%.*s",
999         "refs/tags/%.*s",
1000         "refs/heads/%.*s",
1001         "refs/remotes/%.*s",
1002         "refs/remotes/%.*s/HEAD",
1003         NULL
1004 };
1005
1006 int refname_match(const char *abbrev_name, const char *full_name, const char **rules)
1007 {
1008         const char **p;
1009         const int abbrev_name_len = strlen(abbrev_name);
1010
1011         for (p = rules; *p; p++) {
1012                 if (!strcmp(full_name, mkpath(*p, abbrev_name_len, abbrev_name))) {
1013                         return 1;
1014                 }
1015         }
1016
1017         return 0;
1018 }
1019
1020 static struct ref_lock *verify_lock(struct ref_lock *lock,
1021         const unsigned char *old_sha1, int mustexist)
1022 {
1023         if (read_ref_full(lock->ref_name, lock->old_sha1, mustexist, NULL)) {
1024                 error("Can't verify ref %s", lock->ref_name);
1025                 unlock_ref(lock);
1026                 return NULL;
1027         }
1028         if (hashcmp(lock->old_sha1, old_sha1)) {
1029                 error("Ref %s is at %s but expected %s", lock->ref_name,
1030                         sha1_to_hex(lock->old_sha1), sha1_to_hex(old_sha1));
1031                 unlock_ref(lock);
1032                 return NULL;
1033         }
1034         return lock;
1035 }
1036
1037 static int remove_empty_directories(const char *file)
1038 {
1039         /* we want to create a file but there is a directory there;
1040          * if that is an empty directory (or a directory that contains
1041          * only empty directories), remove them.
1042          */
1043         struct strbuf path;
1044         int result;
1045
1046         strbuf_init(&path, 20);
1047         strbuf_addstr(&path, file);
1048
1049         result = remove_dir_recursively(&path, REMOVE_DIR_EMPTY_ONLY);
1050
1051         strbuf_release(&path);
1052
1053         return result;
1054 }
1055
1056 static int is_refname_available(const char *ref, const char *oldref,
1057                                 struct ref_array *array, int quiet)
1058 {
1059         int i, namlen = strlen(ref); /* e.g. 'foo/bar' */
1060         for (i = 0; i < array->nr; i++ ) {
1061                 struct ref_entry *entry = array->refs[i];
1062                 /* entry->name could be 'foo' or 'foo/bar/baz' */
1063                 if (!oldref || strcmp(oldref, entry->name)) {
1064                         int len = strlen(entry->name);
1065                         int cmplen = (namlen < len) ? namlen : len;
1066                         const char *lead = (namlen < len) ? entry->name : ref;
1067                         if (!strncmp(ref, entry->name, cmplen) &&
1068                             lead[cmplen] == '/') {
1069                                 if (!quiet)
1070                                         error("'%s' exists; cannot create '%s'",
1071                                               entry->name, ref);
1072                                 return 0;
1073                         }
1074                 }
1075         }
1076         return 1;
1077 }
1078
1079 /*
1080  * *string and *len will only be substituted, and *string returned (for
1081  * later free()ing) if the string passed in is a magic short-hand form
1082  * to name a branch.
1083  */
1084 static char *substitute_branch_name(const char **string, int *len)
1085 {
1086         struct strbuf buf = STRBUF_INIT;
1087         int ret = interpret_branch_name(*string, &buf);
1088
1089         if (ret == *len) {
1090                 size_t size;
1091                 *string = strbuf_detach(&buf, &size);
1092                 *len = size;
1093                 return (char *)*string;
1094         }
1095
1096         return NULL;
1097 }
1098
1099 int dwim_ref(const char *str, int len, unsigned char *sha1, char **ref)
1100 {
1101         char *last_branch = substitute_branch_name(&str, &len);
1102         const char **p, *r;
1103         int refs_found = 0;
1104
1105         *ref = NULL;
1106         for (p = ref_rev_parse_rules; *p; p++) {
1107                 char fullref[PATH_MAX];
1108                 unsigned char sha1_from_ref[20];
1109                 unsigned char *this_result;
1110                 int flag;
1111
1112                 this_result = refs_found ? sha1_from_ref : sha1;
1113                 mksnpath(fullref, sizeof(fullref), *p, len, str);
1114                 r = resolve_ref(fullref, this_result, 1, &flag);
1115                 if (r) {
1116                         if (!refs_found++)
1117                                 *ref = xstrdup(r);
1118                         if (!warn_ambiguous_refs)
1119                                 break;
1120                 } else if ((flag & REF_ISSYMREF) && strcmp(fullref, "HEAD")) {
1121                         warning("ignoring dangling symref %s.", fullref);
1122                 } else if ((flag & REF_ISBROKEN) && strchr(fullref, '/')) {
1123                         warning("ignoring broken ref %s.", fullref);
1124                 }
1125         }
1126         free(last_branch);
1127         return refs_found;
1128 }
1129
1130 int dwim_log(const char *str, int len, unsigned char *sha1, char **log)
1131 {
1132         char *last_branch = substitute_branch_name(&str, &len);
1133         const char **p;
1134         int logs_found = 0;
1135
1136         *log = NULL;
1137         for (p = ref_rev_parse_rules; *p; p++) {
1138                 struct stat st;
1139                 unsigned char hash[20];
1140                 char path[PATH_MAX];
1141                 const char *ref, *it;
1142
1143                 mksnpath(path, sizeof(path), *p, len, str);
1144                 ref = resolve_ref(path, hash, 1, NULL);
1145                 if (!ref)
1146                         continue;
1147                 if (!stat(git_path("logs/%s", path), &st) &&
1148                     S_ISREG(st.st_mode))
1149                         it = path;
1150                 else if (strcmp(ref, path) &&
1151                          !stat(git_path("logs/%s", ref), &st) &&
1152                          S_ISREG(st.st_mode))
1153                         it = ref;
1154                 else
1155                         continue;
1156                 if (!logs_found++) {
1157                         *log = xstrdup(it);
1158                         hashcpy(sha1, hash);
1159                 }
1160                 if (!warn_ambiguous_refs)
1161                         break;
1162         }
1163         free(last_branch);
1164         return logs_found;
1165 }
1166
1167 static struct ref_lock *lock_ref_sha1_basic(const char *ref, const unsigned char *old_sha1, int flags, int *type_p)
1168 {
1169         char *ref_file;
1170         const char *orig_ref = ref;
1171         struct ref_lock *lock;
1172         int last_errno = 0;
1173         int type, lflags;
1174         int mustexist = (old_sha1 && !is_null_sha1(old_sha1));
1175         int missing = 0;
1176
1177         lock = xcalloc(1, sizeof(struct ref_lock));
1178         lock->lock_fd = -1;
1179
1180         ref = resolve_ref(ref, lock->old_sha1, mustexist, &type);
1181         if (!ref && errno == EISDIR) {
1182                 /* we are trying to lock foo but we used to
1183                  * have foo/bar which now does not exist;
1184                  * it is normal for the empty directory 'foo'
1185                  * to remain.
1186                  */
1187                 ref_file = git_path("%s", orig_ref);
1188                 if (remove_empty_directories(ref_file)) {
1189                         last_errno = errno;
1190                         error("there are still refs under '%s'", orig_ref);
1191                         goto error_return;
1192                 }
1193                 ref = resolve_ref(orig_ref, lock->old_sha1, mustexist, &type);
1194         }
1195         if (type_p)
1196             *type_p = type;
1197         if (!ref) {
1198                 last_errno = errno;
1199                 error("unable to resolve reference %s: %s",
1200                         orig_ref, strerror(errno));
1201                 goto error_return;
1202         }
1203         missing = is_null_sha1(lock->old_sha1);
1204         /* When the ref did not exist and we are creating it,
1205          * make sure there is no existing ref that is packed
1206          * whose name begins with our refname, nor a ref whose
1207          * name is a proper prefix of our refname.
1208          */
1209         if (missing &&
1210              !is_refname_available(ref, NULL, get_packed_refs(NULL), 0)) {
1211                 last_errno = ENOTDIR;
1212                 goto error_return;
1213         }
1214
1215         lock->lk = xcalloc(1, sizeof(struct lock_file));
1216
1217         lflags = LOCK_DIE_ON_ERROR;
1218         if (flags & REF_NODEREF) {
1219                 ref = orig_ref;
1220                 lflags |= LOCK_NODEREF;
1221         }
1222         lock->ref_name = xstrdup(ref);
1223         lock->orig_ref_name = xstrdup(orig_ref);
1224         ref_file = git_path("%s", ref);
1225         if (missing)
1226                 lock->force_write = 1;
1227         if ((flags & REF_NODEREF) && (type & REF_ISSYMREF))
1228                 lock->force_write = 1;
1229
1230         if (safe_create_leading_directories(ref_file)) {
1231                 last_errno = errno;
1232                 error("unable to create directory for %s", ref_file);
1233                 goto error_return;
1234         }
1235
1236         lock->lock_fd = hold_lock_file_for_update(lock->lk, ref_file, lflags);
1237         return old_sha1 ? verify_lock(lock, old_sha1, mustexist) : lock;
1238
1239  error_return:
1240         unlock_ref(lock);
1241         errno = last_errno;
1242         return NULL;
1243 }
1244
1245 struct ref_lock *lock_ref_sha1(const char *ref, const unsigned char *old_sha1)
1246 {
1247         char refpath[PATH_MAX];
1248         if (check_refname_format(ref, 0))
1249                 return NULL;
1250         strcpy(refpath, mkpath("refs/%s", ref));
1251         return lock_ref_sha1_basic(refpath, old_sha1, 0, NULL);
1252 }
1253
1254 struct ref_lock *lock_any_ref_for_update(const char *ref, const unsigned char *old_sha1, int flags)
1255 {
1256         if (check_refname_format(ref, REFNAME_ALLOW_ONELEVEL))
1257                 return NULL;
1258         return lock_ref_sha1_basic(ref, old_sha1, flags, NULL);
1259 }
1260
1261 static struct lock_file packlock;
1262
1263 static int repack_without_ref(const char *refname)
1264 {
1265         struct ref_array *packed;
1266         struct ref_entry *ref;
1267         int fd, i;
1268
1269         packed = get_packed_refs(NULL);
1270         ref = search_ref_array(packed, refname);
1271         if (ref == NULL)
1272                 return 0;
1273         fd = hold_lock_file_for_update(&packlock, git_path("packed-refs"), 0);
1274         if (fd < 0) {
1275                 unable_to_lock_error(git_path("packed-refs"), errno);
1276                 return error("cannot delete '%s' from packed refs", refname);
1277         }
1278
1279         for (i = 0; i < packed->nr; i++) {
1280                 char line[PATH_MAX + 100];
1281                 int len;
1282
1283                 ref = packed->refs[i];
1284
1285                 if (!strcmp(refname, ref->name))
1286                         continue;
1287                 len = snprintf(line, sizeof(line), "%s %s\n",
1288                                sha1_to_hex(ref->sha1), ref->name);
1289                 /* this should not happen but just being defensive */
1290                 if (len > sizeof(line))
1291                         die("too long a refname '%s'", ref->name);
1292                 write_or_die(fd, line, len);
1293         }
1294         return commit_lock_file(&packlock);
1295 }
1296
1297 int delete_ref(const char *refname, const unsigned char *sha1, int delopt)
1298 {
1299         struct ref_lock *lock;
1300         int err, i = 0, ret = 0, flag = 0;
1301
1302         lock = lock_ref_sha1_basic(refname, sha1, 0, &flag);
1303         if (!lock)
1304                 return 1;
1305         if (!(flag & REF_ISPACKED) || flag & REF_ISSYMREF) {
1306                 /* loose */
1307                 const char *path;
1308
1309                 if (!(delopt & REF_NODEREF)) {
1310                         i = strlen(lock->lk->filename) - 5; /* .lock */
1311                         lock->lk->filename[i] = 0;
1312                         path = lock->lk->filename;
1313                 } else {
1314                         path = git_path("%s", refname);
1315                 }
1316                 err = unlink_or_warn(path);
1317                 if (err && errno != ENOENT)
1318                         ret = 1;
1319
1320                 if (!(delopt & REF_NODEREF))
1321                         lock->lk->filename[i] = '.';
1322         }
1323         /* removing the loose one could have resurrected an earlier
1324          * packed one.  Also, if it was not loose we need to repack
1325          * without it.
1326          */
1327         ret |= repack_without_ref(refname);
1328
1329         unlink_or_warn(git_path("logs/%s", lock->ref_name));
1330         invalidate_ref_cache(NULL);
1331         unlock_ref(lock);
1332         return ret;
1333 }
1334
1335 /*
1336  * People using contrib's git-new-workdir have .git/logs/refs ->
1337  * /some/other/path/.git/logs/refs, and that may live on another device.
1338  *
1339  * IOW, to avoid cross device rename errors, the temporary renamed log must
1340  * live into logs/refs.
1341  */
1342 #define TMP_RENAMED_LOG  "logs/refs/.tmp-renamed-log"
1343
1344 int rename_ref(const char *oldref, const char *newref, const char *logmsg)
1345 {
1346         unsigned char sha1[20], orig_sha1[20];
1347         int flag = 0, logmoved = 0;
1348         struct ref_lock *lock;
1349         struct stat loginfo;
1350         int log = !lstat(git_path("logs/%s", oldref), &loginfo);
1351         const char *symref = NULL;
1352
1353         if (log && S_ISLNK(loginfo.st_mode))
1354                 return error("reflog for %s is a symlink", oldref);
1355
1356         symref = resolve_ref(oldref, orig_sha1, 1, &flag);
1357         if (flag & REF_ISSYMREF)
1358                 return error("refname %s is a symbolic ref, renaming it is not supported",
1359                         oldref);
1360         if (!symref)
1361                 return error("refname %s not found", oldref);
1362
1363         if (!is_refname_available(newref, oldref, get_packed_refs(NULL), 0))
1364                 return 1;
1365
1366         if (!is_refname_available(newref, oldref, get_loose_refs(NULL), 0))
1367                 return 1;
1368
1369         if (log && rename(git_path("logs/%s", oldref), git_path(TMP_RENAMED_LOG)))
1370                 return error("unable to move logfile logs/%s to "TMP_RENAMED_LOG": %s",
1371                         oldref, strerror(errno));
1372
1373         if (delete_ref(oldref, orig_sha1, REF_NODEREF)) {
1374                 error("unable to delete old %s", oldref);
1375                 goto rollback;
1376         }
1377
1378         if (!read_ref_full(newref, sha1, 1, &flag) &&
1379             delete_ref(newref, sha1, REF_NODEREF)) {
1380                 if (errno==EISDIR) {
1381                         if (remove_empty_directories(git_path("%s", newref))) {
1382                                 error("Directory not empty: %s", newref);
1383                                 goto rollback;
1384                         }
1385                 } else {
1386                         error("unable to delete existing %s", newref);
1387                         goto rollback;
1388                 }
1389         }
1390
1391         if (log && safe_create_leading_directories(git_path("logs/%s", newref))) {
1392                 error("unable to create directory for %s", newref);
1393                 goto rollback;
1394         }
1395
1396  retry:
1397         if (log && rename(git_path(TMP_RENAMED_LOG), git_path("logs/%s", newref))) {
1398                 if (errno==EISDIR || errno==ENOTDIR) {
1399                         /*
1400                          * rename(a, b) when b is an existing
1401                          * directory ought to result in ISDIR, but
1402                          * Solaris 5.8 gives ENOTDIR.  Sheesh.
1403                          */
1404                         if (remove_empty_directories(git_path("logs/%s", newref))) {
1405                                 error("Directory not empty: logs/%s", newref);
1406                                 goto rollback;
1407                         }
1408                         goto retry;
1409                 } else {
1410                         error("unable to move logfile "TMP_RENAMED_LOG" to logs/%s: %s",
1411                                 newref, strerror(errno));
1412                         goto rollback;
1413                 }
1414         }
1415         logmoved = log;
1416
1417         lock = lock_ref_sha1_basic(newref, NULL, 0, NULL);
1418         if (!lock) {
1419                 error("unable to lock %s for update", newref);
1420                 goto rollback;
1421         }
1422         lock->force_write = 1;
1423         hashcpy(lock->old_sha1, orig_sha1);
1424         if (write_ref_sha1(lock, orig_sha1, logmsg)) {
1425                 error("unable to write current sha1 into %s", newref);
1426                 goto rollback;
1427         }
1428
1429         return 0;
1430
1431  rollback:
1432         lock = lock_ref_sha1_basic(oldref, NULL, 0, NULL);
1433         if (!lock) {
1434                 error("unable to lock %s for rollback", oldref);
1435                 goto rollbacklog;
1436         }
1437
1438         lock->force_write = 1;
1439         flag = log_all_ref_updates;
1440         log_all_ref_updates = 0;
1441         if (write_ref_sha1(lock, orig_sha1, NULL))
1442                 error("unable to write current sha1 into %s", oldref);
1443         log_all_ref_updates = flag;
1444
1445  rollbacklog:
1446         if (logmoved && rename(git_path("logs/%s", newref), git_path("logs/%s", oldref)))
1447                 error("unable to restore logfile %s from %s: %s",
1448                         oldref, newref, strerror(errno));
1449         if (!logmoved && log &&
1450             rename(git_path(TMP_RENAMED_LOG), git_path("logs/%s", oldref)))
1451                 error("unable to restore logfile %s from "TMP_RENAMED_LOG": %s",
1452                         oldref, strerror(errno));
1453
1454         return 1;
1455 }
1456
1457 int close_ref(struct ref_lock *lock)
1458 {
1459         if (close_lock_file(lock->lk))
1460                 return -1;
1461         lock->lock_fd = -1;
1462         return 0;
1463 }
1464
1465 int commit_ref(struct ref_lock *lock)
1466 {
1467         if (commit_lock_file(lock->lk))
1468                 return -1;
1469         lock->lock_fd = -1;
1470         return 0;
1471 }
1472
1473 void unlock_ref(struct ref_lock *lock)
1474 {
1475         /* Do not free lock->lk -- atexit() still looks at them */
1476         if (lock->lk)
1477                 rollback_lock_file(lock->lk);
1478         free(lock->ref_name);
1479         free(lock->orig_ref_name);
1480         free(lock);
1481 }
1482
1483 /*
1484  * copy the reflog message msg to buf, which has been allocated sufficiently
1485  * large, while cleaning up the whitespaces.  Especially, convert LF to space,
1486  * because reflog file is one line per entry.
1487  */
1488 static int copy_msg(char *buf, const char *msg)
1489 {
1490         char *cp = buf;
1491         char c;
1492         int wasspace = 1;
1493
1494         *cp++ = '\t';
1495         while ((c = *msg++)) {
1496                 if (wasspace && isspace(c))
1497                         continue;
1498                 wasspace = isspace(c);
1499                 if (wasspace)
1500                         c = ' ';
1501                 *cp++ = c;
1502         }
1503         while (buf < cp && isspace(cp[-1]))
1504                 cp--;
1505         *cp++ = '\n';
1506         return cp - buf;
1507 }
1508
1509 int log_ref_setup(const char *ref_name, char *logfile, int bufsize)
1510 {
1511         int logfd, oflags = O_APPEND | O_WRONLY;
1512
1513         git_snpath(logfile, bufsize, "logs/%s", ref_name);
1514         if (log_all_ref_updates &&
1515             (!prefixcmp(ref_name, "refs/heads/") ||
1516              !prefixcmp(ref_name, "refs/remotes/") ||
1517              !prefixcmp(ref_name, "refs/notes/") ||
1518              !strcmp(ref_name, "HEAD"))) {
1519                 if (safe_create_leading_directories(logfile) < 0)
1520                         return error("unable to create directory for %s",
1521                                      logfile);
1522                 oflags |= O_CREAT;
1523         }
1524
1525         logfd = open(logfile, oflags, 0666);
1526         if (logfd < 0) {
1527                 if (!(oflags & O_CREAT) && errno == ENOENT)
1528                         return 0;
1529
1530                 if ((oflags & O_CREAT) && errno == EISDIR) {
1531                         if (remove_empty_directories(logfile)) {
1532                                 return error("There are still logs under '%s'",
1533                                              logfile);
1534                         }
1535                         logfd = open(logfile, oflags, 0666);
1536                 }
1537
1538                 if (logfd < 0)
1539                         return error("Unable to append to %s: %s",
1540                                      logfile, strerror(errno));
1541         }
1542
1543         adjust_shared_perm(logfile);
1544         close(logfd);
1545         return 0;
1546 }
1547
1548 static int log_ref_write(const char *ref_name, const unsigned char *old_sha1,
1549                          const unsigned char *new_sha1, const char *msg)
1550 {
1551         int logfd, result, written, oflags = O_APPEND | O_WRONLY;
1552         unsigned maxlen, len;
1553         int msglen;
1554         char log_file[PATH_MAX];
1555         char *logrec;
1556         const char *committer;
1557
1558         if (log_all_ref_updates < 0)
1559                 log_all_ref_updates = !is_bare_repository();
1560
1561         result = log_ref_setup(ref_name, log_file, sizeof(log_file));
1562         if (result)
1563                 return result;
1564
1565         logfd = open(log_file, oflags);
1566         if (logfd < 0)
1567                 return 0;
1568         msglen = msg ? strlen(msg) : 0;
1569         committer = git_committer_info(0);
1570         maxlen = strlen(committer) + msglen + 100;
1571         logrec = xmalloc(maxlen);
1572         len = sprintf(logrec, "%s %s %s\n",
1573                       sha1_to_hex(old_sha1),
1574                       sha1_to_hex(new_sha1),
1575                       committer);
1576         if (msglen)
1577                 len += copy_msg(logrec + len - 1, msg) - 1;
1578         written = len <= maxlen ? write_in_full(logfd, logrec, len) : -1;
1579         free(logrec);
1580         if (close(logfd) != 0 || written != len)
1581                 return error("Unable to append to %s", log_file);
1582         return 0;
1583 }
1584
1585 static int is_branch(const char *refname)
1586 {
1587         return !strcmp(refname, "HEAD") || !prefixcmp(refname, "refs/heads/");
1588 }
1589
1590 int write_ref_sha1(struct ref_lock *lock,
1591         const unsigned char *sha1, const char *logmsg)
1592 {
1593         static char term = '\n';
1594         struct object *o;
1595
1596         if (!lock)
1597                 return -1;
1598         if (!lock->force_write && !hashcmp(lock->old_sha1, sha1)) {
1599                 unlock_ref(lock);
1600                 return 0;
1601         }
1602         o = parse_object(sha1);
1603         if (!o) {
1604                 error("Trying to write ref %s with nonexistent object %s",
1605                         lock->ref_name, sha1_to_hex(sha1));
1606                 unlock_ref(lock);
1607                 return -1;
1608         }
1609         if (o->type != OBJ_COMMIT && is_branch(lock->ref_name)) {
1610                 error("Trying to write non-commit object %s to branch %s",
1611                         sha1_to_hex(sha1), lock->ref_name);
1612                 unlock_ref(lock);
1613                 return -1;
1614         }
1615         if (write_in_full(lock->lock_fd, sha1_to_hex(sha1), 40) != 40 ||
1616             write_in_full(lock->lock_fd, &term, 1) != 1
1617                 || close_ref(lock) < 0) {
1618                 error("Couldn't write %s", lock->lk->filename);
1619                 unlock_ref(lock);
1620                 return -1;
1621         }
1622         clear_loose_ref_cache(get_ref_cache(NULL));
1623         if (log_ref_write(lock->ref_name, lock->old_sha1, sha1, logmsg) < 0 ||
1624             (strcmp(lock->ref_name, lock->orig_ref_name) &&
1625              log_ref_write(lock->orig_ref_name, lock->old_sha1, sha1, logmsg) < 0)) {
1626                 unlock_ref(lock);
1627                 return -1;
1628         }
1629         if (strcmp(lock->orig_ref_name, "HEAD") != 0) {
1630                 /*
1631                  * Special hack: If a branch is updated directly and HEAD
1632                  * points to it (may happen on the remote side of a push
1633                  * for example) then logically the HEAD reflog should be
1634                  * updated too.
1635                  * A generic solution implies reverse symref information,
1636                  * but finding all symrefs pointing to the given branch
1637                  * would be rather costly for this rare event (the direct
1638                  * update of a branch) to be worth it.  So let's cheat and
1639                  * check with HEAD only which should cover 99% of all usage
1640                  * scenarios (even 100% of the default ones).
1641                  */
1642                 unsigned char head_sha1[20];
1643                 int head_flag;
1644                 const char *head_ref;
1645                 head_ref = resolve_ref("HEAD", head_sha1, 1, &head_flag);
1646                 if (head_ref && (head_flag & REF_ISSYMREF) &&
1647                     !strcmp(head_ref, lock->ref_name))
1648                         log_ref_write("HEAD", lock->old_sha1, sha1, logmsg);
1649         }
1650         if (commit_ref(lock)) {
1651                 error("Couldn't set %s", lock->ref_name);
1652                 unlock_ref(lock);
1653                 return -1;
1654         }
1655         unlock_ref(lock);
1656         return 0;
1657 }
1658
1659 int create_symref(const char *ref_target, const char *refs_heads_master,
1660                   const char *logmsg)
1661 {
1662         const char *lockpath;
1663         char ref[1000];
1664         int fd, len, written;
1665         char *git_HEAD = git_pathdup("%s", ref_target);
1666         unsigned char old_sha1[20], new_sha1[20];
1667
1668         if (logmsg && read_ref(ref_target, old_sha1))
1669                 hashclr(old_sha1);
1670
1671         if (safe_create_leading_directories(git_HEAD) < 0)
1672                 return error("unable to create directory for %s", git_HEAD);
1673
1674 #ifndef NO_SYMLINK_HEAD
1675         if (prefer_symlink_refs) {
1676                 unlink(git_HEAD);
1677                 if (!symlink(refs_heads_master, git_HEAD))
1678                         goto done;
1679                 fprintf(stderr, "no symlink - falling back to symbolic ref\n");
1680         }
1681 #endif
1682
1683         len = snprintf(ref, sizeof(ref), "ref: %s\n", refs_heads_master);
1684         if (sizeof(ref) <= len) {
1685                 error("refname too long: %s", refs_heads_master);
1686                 goto error_free_return;
1687         }
1688         lockpath = mkpath("%s.lock", git_HEAD);
1689         fd = open(lockpath, O_CREAT | O_EXCL | O_WRONLY, 0666);
1690         if (fd < 0) {
1691                 error("Unable to open %s for writing", lockpath);
1692                 goto error_free_return;
1693         }
1694         written = write_in_full(fd, ref, len);
1695         if (close(fd) != 0 || written != len) {
1696                 error("Unable to write to %s", lockpath);
1697                 goto error_unlink_return;
1698         }
1699         if (rename(lockpath, git_HEAD) < 0) {
1700                 error("Unable to create %s", git_HEAD);
1701                 goto error_unlink_return;
1702         }
1703         if (adjust_shared_perm(git_HEAD)) {
1704                 error("Unable to fix permissions on %s", lockpath);
1705         error_unlink_return:
1706                 unlink_or_warn(lockpath);
1707         error_free_return:
1708                 free(git_HEAD);
1709                 return -1;
1710         }
1711
1712 #ifndef NO_SYMLINK_HEAD
1713         done:
1714 #endif
1715         if (logmsg && !read_ref(refs_heads_master, new_sha1))
1716                 log_ref_write(ref_target, old_sha1, new_sha1, logmsg);
1717
1718         free(git_HEAD);
1719         return 0;
1720 }
1721
1722 static char *ref_msg(const char *line, const char *endp)
1723 {
1724         const char *ep;
1725         line += 82;
1726         ep = memchr(line, '\n', endp - line);
1727         if (!ep)
1728                 ep = endp;
1729         return xmemdupz(line, ep - line);
1730 }
1731
1732 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)
1733 {
1734         const char *logfile, *logdata, *logend, *rec, *lastgt, *lastrec;
1735         char *tz_c;
1736         int logfd, tz, reccnt = 0;
1737         struct stat st;
1738         unsigned long date;
1739         unsigned char logged_sha1[20];
1740         void *log_mapped;
1741         size_t mapsz;
1742
1743         logfile = git_path("logs/%s", ref);
1744         logfd = open(logfile, O_RDONLY, 0);
1745         if (logfd < 0)
1746                 die_errno("Unable to read log '%s'", logfile);
1747         fstat(logfd, &st);
1748         if (!st.st_size)
1749                 die("Log %s is empty.", logfile);
1750         mapsz = xsize_t(st.st_size);
1751         log_mapped = xmmap(NULL, mapsz, PROT_READ, MAP_PRIVATE, logfd, 0);
1752         logdata = log_mapped;
1753         close(logfd);
1754
1755         lastrec = NULL;
1756         rec = logend = logdata + st.st_size;
1757         while (logdata < rec) {
1758                 reccnt++;
1759                 if (logdata < rec && *(rec-1) == '\n')
1760                         rec--;
1761                 lastgt = NULL;
1762                 while (logdata < rec && *(rec-1) != '\n') {
1763                         rec--;
1764                         if (*rec == '>')
1765                                 lastgt = rec;
1766                 }
1767                 if (!lastgt)
1768                         die("Log %s is corrupt.", logfile);
1769                 date = strtoul(lastgt + 1, &tz_c, 10);
1770                 if (date <= at_time || cnt == 0) {
1771                         tz = strtoul(tz_c, NULL, 10);
1772                         if (msg)
1773                                 *msg = ref_msg(rec, logend);
1774                         if (cutoff_time)
1775                                 *cutoff_time = date;
1776                         if (cutoff_tz)
1777                                 *cutoff_tz = tz;
1778                         if (cutoff_cnt)
1779                                 *cutoff_cnt = reccnt - 1;
1780                         if (lastrec) {
1781                                 if (get_sha1_hex(lastrec, logged_sha1))
1782                                         die("Log %s is corrupt.", logfile);
1783                                 if (get_sha1_hex(rec + 41, sha1))
1784                                         die("Log %s is corrupt.", logfile);
1785                                 if (hashcmp(logged_sha1, sha1)) {
1786                                         warning("Log %s has gap after %s.",
1787                                                 logfile, show_date(date, tz, DATE_RFC2822));
1788                                 }
1789                         }
1790                         else if (date == at_time) {
1791                                 if (get_sha1_hex(rec + 41, sha1))
1792                                         die("Log %s is corrupt.", logfile);
1793                         }
1794                         else {
1795                                 if (get_sha1_hex(rec + 41, logged_sha1))
1796                                         die("Log %s is corrupt.", logfile);
1797                                 if (hashcmp(logged_sha1, sha1)) {
1798                                         warning("Log %s unexpectedly ended on %s.",
1799                                                 logfile, show_date(date, tz, DATE_RFC2822));
1800                                 }
1801                         }
1802                         munmap(log_mapped, mapsz);
1803                         return 0;
1804                 }
1805                 lastrec = rec;
1806                 if (cnt > 0)
1807                         cnt--;
1808         }
1809
1810         rec = logdata;
1811         while (rec < logend && *rec != '>' && *rec != '\n')
1812                 rec++;
1813         if (rec == logend || *rec == '\n')
1814                 die("Log %s is corrupt.", logfile);
1815         date = strtoul(rec + 1, &tz_c, 10);
1816         tz = strtoul(tz_c, NULL, 10);
1817         if (get_sha1_hex(logdata, sha1))
1818                 die("Log %s is corrupt.", logfile);
1819         if (is_null_sha1(sha1)) {
1820                 if (get_sha1_hex(logdata + 41, sha1))
1821                         die("Log %s is corrupt.", logfile);
1822         }
1823         if (msg)
1824                 *msg = ref_msg(logdata, logend);
1825         munmap(log_mapped, mapsz);
1826
1827         if (cutoff_time)
1828                 *cutoff_time = date;
1829         if (cutoff_tz)
1830                 *cutoff_tz = tz;
1831         if (cutoff_cnt)
1832                 *cutoff_cnt = reccnt;
1833         return 1;
1834 }
1835
1836 int for_each_recent_reflog_ent(const char *ref, each_reflog_ent_fn fn, long ofs, void *cb_data)
1837 {
1838         const char *logfile;
1839         FILE *logfp;
1840         struct strbuf sb = STRBUF_INIT;
1841         int ret = 0;
1842
1843         logfile = git_path("logs/%s", ref);
1844         logfp = fopen(logfile, "r");
1845         if (!logfp)
1846                 return -1;
1847
1848         if (ofs) {
1849                 struct stat statbuf;
1850                 if (fstat(fileno(logfp), &statbuf) ||
1851                     statbuf.st_size < ofs ||
1852                     fseek(logfp, -ofs, SEEK_END) ||
1853                     strbuf_getwholeline(&sb, logfp, '\n')) {
1854                         fclose(logfp);
1855                         strbuf_release(&sb);
1856                         return -1;
1857                 }
1858         }
1859
1860         while (!strbuf_getwholeline(&sb, logfp, '\n')) {
1861                 unsigned char osha1[20], nsha1[20];
1862                 char *email_end, *message;
1863                 unsigned long timestamp;
1864                 int tz;
1865
1866                 /* old SP new SP name <email> SP time TAB msg LF */
1867                 if (sb.len < 83 || sb.buf[sb.len - 1] != '\n' ||
1868                     get_sha1_hex(sb.buf, osha1) || sb.buf[40] != ' ' ||
1869                     get_sha1_hex(sb.buf + 41, nsha1) || sb.buf[81] != ' ' ||
1870                     !(email_end = strchr(sb.buf + 82, '>')) ||
1871                     email_end[1] != ' ' ||
1872                     !(timestamp = strtoul(email_end + 2, &message, 10)) ||
1873                     !message || message[0] != ' ' ||
1874                     (message[1] != '+' && message[1] != '-') ||
1875                     !isdigit(message[2]) || !isdigit(message[3]) ||
1876                     !isdigit(message[4]) || !isdigit(message[5]))
1877                         continue; /* corrupt? */
1878                 email_end[1] = '\0';
1879                 tz = strtol(message + 1, NULL, 10);
1880                 if (message[6] != '\t')
1881                         message += 6;
1882                 else
1883                         message += 7;
1884                 ret = fn(osha1, nsha1, sb.buf + 82, timestamp, tz, message,
1885                          cb_data);
1886                 if (ret)
1887                         break;
1888         }
1889         fclose(logfp);
1890         strbuf_release(&sb);
1891         return ret;
1892 }
1893
1894 int for_each_reflog_ent(const char *ref, each_reflog_ent_fn fn, void *cb_data)
1895 {
1896         return for_each_recent_reflog_ent(ref, fn, 0, cb_data);
1897 }
1898
1899 static int do_for_each_reflog(const char *base, each_ref_fn fn, void *cb_data)
1900 {
1901         DIR *dir = opendir(git_path("logs/%s", base));
1902         int retval = 0;
1903
1904         if (dir) {
1905                 struct dirent *de;
1906                 int baselen = strlen(base);
1907                 char *log = xmalloc(baselen + 257);
1908
1909                 memcpy(log, base, baselen);
1910                 if (baselen && base[baselen-1] != '/')
1911                         log[baselen++] = '/';
1912
1913                 while ((de = readdir(dir)) != NULL) {
1914                         struct stat st;
1915                         int namelen;
1916
1917                         if (de->d_name[0] == '.')
1918                                 continue;
1919                         namelen = strlen(de->d_name);
1920                         if (namelen > 255)
1921                                 continue;
1922                         if (has_extension(de->d_name, ".lock"))
1923                                 continue;
1924                         memcpy(log + baselen, de->d_name, namelen+1);
1925                         if (stat(git_path("logs/%s", log), &st) < 0)
1926                                 continue;
1927                         if (S_ISDIR(st.st_mode)) {
1928                                 retval = do_for_each_reflog(log, fn, cb_data);
1929                         } else {
1930                                 unsigned char sha1[20];
1931                                 if (read_ref_full(log, sha1, 0, NULL))
1932                                         retval = error("bad ref for %s", log);
1933                                 else
1934                                         retval = fn(log, sha1, 0, cb_data);
1935                         }
1936                         if (retval)
1937                                 break;
1938                 }
1939                 free(log);
1940                 closedir(dir);
1941         }
1942         else if (*base)
1943                 return errno;
1944         return retval;
1945 }
1946
1947 int for_each_reflog(each_ref_fn fn, void *cb_data)
1948 {
1949         return do_for_each_reflog("", fn, cb_data);
1950 }
1951
1952 int update_ref(const char *action, const char *refname,
1953                 const unsigned char *sha1, const unsigned char *oldval,
1954                 int flags, enum action_on_err onerr)
1955 {
1956         static struct ref_lock *lock;
1957         lock = lock_any_ref_for_update(refname, oldval, flags);
1958         if (!lock) {
1959                 const char *str = "Cannot lock the ref '%s'.";
1960                 switch (onerr) {
1961                 case MSG_ON_ERR: error(str, refname); break;
1962                 case DIE_ON_ERR: die(str, refname); break;
1963                 case QUIET_ON_ERR: break;
1964                 }
1965                 return 1;
1966         }
1967         if (write_ref_sha1(lock, sha1, action) < 0) {
1968                 const char *str = "Cannot update the ref '%s'.";
1969                 switch (onerr) {
1970                 case MSG_ON_ERR: error(str, refname); break;
1971                 case DIE_ON_ERR: die(str, refname); break;
1972                 case QUIET_ON_ERR: break;
1973                 }
1974                 return 1;
1975         }
1976         return 0;
1977 }
1978
1979 int ref_exists(const char *refname)
1980 {
1981         unsigned char sha1[20];
1982         return !!resolve_ref(refname, sha1, 1, NULL);
1983 }
1984
1985 struct ref *find_ref_by_name(const struct ref *list, const char *name)
1986 {
1987         for ( ; list; list = list->next)
1988                 if (!strcmp(list->name, name))
1989                         return (struct ref *)list;
1990         return NULL;
1991 }
1992
1993 /*
1994  * generate a format suitable for scanf from a ref_rev_parse_rules
1995  * rule, that is replace the "%.*s" spec with a "%s" spec
1996  */
1997 static void gen_scanf_fmt(char *scanf_fmt, const char *rule)
1998 {
1999         char *spec;
2000
2001         spec = strstr(rule, "%.*s");
2002         if (!spec || strstr(spec + 4, "%.*s"))
2003                 die("invalid rule in ref_rev_parse_rules: %s", rule);
2004
2005         /* copy all until spec */
2006         strncpy(scanf_fmt, rule, spec - rule);
2007         scanf_fmt[spec - rule] = '\0';
2008         /* copy new spec */
2009         strcat(scanf_fmt, "%s");
2010         /* copy remaining rule */
2011         strcat(scanf_fmt, spec + 4);
2012
2013         return;
2014 }
2015
2016 char *shorten_unambiguous_ref(const char *ref, int strict)
2017 {
2018         int i;
2019         static char **scanf_fmts;
2020         static int nr_rules;
2021         char *short_name;
2022
2023         /* pre generate scanf formats from ref_rev_parse_rules[] */
2024         if (!nr_rules) {
2025                 size_t total_len = 0;
2026
2027                 /* the rule list is NULL terminated, count them first */
2028                 for (; ref_rev_parse_rules[nr_rules]; nr_rules++)
2029                         /* no +1 because strlen("%s") < strlen("%.*s") */
2030                         total_len += strlen(ref_rev_parse_rules[nr_rules]);
2031
2032                 scanf_fmts = xmalloc(nr_rules * sizeof(char *) + total_len);
2033
2034                 total_len = 0;
2035                 for (i = 0; i < nr_rules; i++) {
2036                         scanf_fmts[i] = (char *)&scanf_fmts[nr_rules]
2037                                         + total_len;
2038                         gen_scanf_fmt(scanf_fmts[i], ref_rev_parse_rules[i]);
2039                         total_len += strlen(ref_rev_parse_rules[i]);
2040                 }
2041         }
2042
2043         /* bail out if there are no rules */
2044         if (!nr_rules)
2045                 return xstrdup(ref);
2046
2047         /* buffer for scanf result, at most ref must fit */
2048         short_name = xstrdup(ref);
2049
2050         /* skip first rule, it will always match */
2051         for (i = nr_rules - 1; i > 0 ; --i) {
2052                 int j;
2053                 int rules_to_fail = i;
2054                 int short_name_len;
2055
2056                 if (1 != sscanf(ref, scanf_fmts[i], short_name))
2057                         continue;
2058
2059                 short_name_len = strlen(short_name);
2060
2061                 /*
2062                  * in strict mode, all (except the matched one) rules
2063                  * must fail to resolve to a valid non-ambiguous ref
2064                  */
2065                 if (strict)
2066                         rules_to_fail = nr_rules;
2067
2068                 /*
2069                  * check if the short name resolves to a valid ref,
2070                  * but use only rules prior to the matched one
2071                  */
2072                 for (j = 0; j < rules_to_fail; j++) {
2073                         const char *rule = ref_rev_parse_rules[j];
2074                         char refname[PATH_MAX];
2075
2076                         /* skip matched rule */
2077                         if (i == j)
2078                                 continue;
2079
2080                         /*
2081                          * the short name is ambiguous, if it resolves
2082                          * (with this previous rule) to a valid ref
2083                          * read_ref() returns 0 on success
2084                          */
2085                         mksnpath(refname, sizeof(refname),
2086                                  rule, short_name_len, short_name);
2087                         if (ref_exists(refname))
2088                                 break;
2089                 }
2090
2091                 /*
2092                  * short name is non-ambiguous if all previous rules
2093                  * haven't resolved to a valid ref
2094                  */
2095                 if (j == rules_to_fail)
2096                         return short_name;
2097         }
2098
2099         free(short_name);
2100         return xstrdup(ref);
2101 }