Fix typo in draft 1.5.4 release notes
[git] / refs.c
1 #include "cache.h"
2 #include "refs.h"
3 #include "object.h"
4 #include "tag.h"
5 #include "dir.h"
6
7 /* ISSYMREF=01 and ISPACKED=02 are public interfaces */
8 #define REF_KNOWS_PEELED 04
9
10 struct ref_list {
11         struct ref_list *next;
12         unsigned char flag; /* ISSYMREF? ISPACKED? */
13         unsigned char sha1[20];
14         unsigned char peeled[20];
15         char name[FLEX_ARRAY];
16 };
17
18 static const char *parse_ref_line(char *line, unsigned char *sha1)
19 {
20         /*
21          * 42: the answer to everything.
22          *
23          * In this case, it happens to be the answer to
24          *  40 (length of sha1 hex representation)
25          *  +1 (space in between hex and name)
26          *  +1 (newline at the end of the line)
27          */
28         int len = strlen(line) - 42;
29
30         if (len <= 0)
31                 return NULL;
32         if (get_sha1_hex(line, sha1) < 0)
33                 return NULL;
34         if (!isspace(line[40]))
35                 return NULL;
36         line += 41;
37         if (isspace(*line))
38                 return NULL;
39         if (line[len] != '\n')
40                 return NULL;
41         line[len] = 0;
42
43         return line;
44 }
45
46 static struct ref_list *add_ref(const char *name, const unsigned char *sha1,
47                                 int flag, struct ref_list *list,
48                                 struct ref_list **new_entry)
49 {
50         int len;
51         struct ref_list *entry;
52
53         /* Allocate it and add it in.. */
54         len = strlen(name) + 1;
55         entry = xmalloc(sizeof(struct ref_list) + len);
56         hashcpy(entry->sha1, sha1);
57         hashclr(entry->peeled);
58         memcpy(entry->name, name, len);
59         entry->flag = flag;
60         entry->next = list;
61         if (new_entry)
62                 *new_entry = entry;
63         return entry;
64 }
65
66 /* merge sort the ref list */
67 static struct ref_list *sort_ref_list(struct ref_list *list)
68 {
69         int psize, qsize, last_merge_count, cmp;
70         struct ref_list *p, *q, *l, *e;
71         struct ref_list *new_list = list;
72         int k = 1;
73         int merge_count = 0;
74
75         if (!list)
76                 return list;
77
78         do {
79                 last_merge_count = merge_count;
80                 merge_count = 0;
81
82                 psize = 0;
83
84                 p = new_list;
85                 q = new_list;
86                 new_list = NULL;
87                 l = NULL;
88
89                 while (p) {
90                         merge_count++;
91
92                         while (psize < k && q->next) {
93                                 q = q->next;
94                                 psize++;
95                         }
96                         qsize = k;
97
98                         while ((psize > 0) || (qsize > 0 && q)) {
99                                 if (qsize == 0 || !q) {
100                                         e = p;
101                                         p = p->next;
102                                         psize--;
103                                 } else if (psize == 0) {
104                                         e = q;
105                                         q = q->next;
106                                         qsize--;
107                                 } else {
108                                         cmp = strcmp(q->name, p->name);
109                                         if (cmp < 0) {
110                                                 e = q;
111                                                 q = q->next;
112                                                 qsize--;
113                                         } else if (cmp > 0) {
114                                                 e = p;
115                                                 p = p->next;
116                                                 psize--;
117                                         } else {
118                                                 if (hashcmp(q->sha1, p->sha1))
119                                                         die("Duplicated ref, and SHA1s don't match: %s",
120                                                             q->name);
121                                                 warning("Duplicated ref: %s", q->name);
122                                                 e = q;
123                                                 q = q->next;
124                                                 qsize--;
125                                                 free(e);
126                                                 e = p;
127                                                 p = p->next;
128                                                 psize--;
129                                         }
130                                 }
131
132                                 e->next = NULL;
133
134                                 if (l)
135                                         l->next = e;
136                                 if (!new_list)
137                                         new_list = e;
138                                 l = e;
139                         }
140
141                         p = q;
142                 };
143
144                 k = k * 2;
145         } while ((last_merge_count != merge_count) || (last_merge_count != 1));
146
147         return new_list;
148 }
149
150 /*
151  * Future: need to be in "struct repository"
152  * when doing a full libification.
153  */
154 static struct cached_refs {
155         char did_loose;
156         char did_packed;
157         struct ref_list *loose;
158         struct ref_list *packed;
159 } cached_refs;
160
161 static void free_ref_list(struct ref_list *list)
162 {
163         struct ref_list *next;
164         for ( ; list; list = next) {
165                 next = list->next;
166                 free(list);
167         }
168 }
169
170 static void invalidate_cached_refs(void)
171 {
172         struct cached_refs *ca = &cached_refs;
173
174         if (ca->did_loose && ca->loose)
175                 free_ref_list(ca->loose);
176         if (ca->did_packed && ca->packed)
177                 free_ref_list(ca->packed);
178         ca->loose = ca->packed = NULL;
179         ca->did_loose = ca->did_packed = 0;
180 }
181
182 static void read_packed_refs(FILE *f, struct cached_refs *cached_refs)
183 {
184         struct ref_list *list = NULL;
185         struct ref_list *last = NULL;
186         char refline[PATH_MAX];
187         int flag = REF_ISPACKED;
188
189         while (fgets(refline, sizeof(refline), f)) {
190                 unsigned char sha1[20];
191                 const char *name;
192                 static const char header[] = "# pack-refs with:";
193
194                 if (!strncmp(refline, header, sizeof(header)-1)) {
195                         const char *traits = refline + sizeof(header) - 1;
196                         if (strstr(traits, " peeled "))
197                                 flag |= REF_KNOWS_PEELED;
198                         /* perhaps other traits later as well */
199                         continue;
200                 }
201
202                 name = parse_ref_line(refline, sha1);
203                 if (name) {
204                         list = add_ref(name, sha1, flag, list, &last);
205                         continue;
206                 }
207                 if (last &&
208                     refline[0] == '^' &&
209                     strlen(refline) == 42 &&
210                     refline[41] == '\n' &&
211                     !get_sha1_hex(refline + 1, sha1))
212                         hashcpy(last->peeled, sha1);
213         }
214         cached_refs->packed = sort_ref_list(list);
215 }
216
217 static struct ref_list *get_packed_refs(void)
218 {
219         if (!cached_refs.did_packed) {
220                 FILE *f = fopen(git_path("packed-refs"), "r");
221                 cached_refs.packed = NULL;
222                 if (f) {
223                         read_packed_refs(f, &cached_refs);
224                         fclose(f);
225                 }
226                 cached_refs.did_packed = 1;
227         }
228         return cached_refs.packed;
229 }
230
231 static struct ref_list *get_ref_dir(const char *base, struct ref_list *list)
232 {
233         DIR *dir = opendir(git_path("%s", base));
234
235         if (dir) {
236                 struct dirent *de;
237                 int baselen = strlen(base);
238                 char *ref = xmalloc(baselen + 257);
239
240                 memcpy(ref, base, baselen);
241                 if (baselen && base[baselen-1] != '/')
242                         ref[baselen++] = '/';
243
244                 while ((de = readdir(dir)) != NULL) {
245                         unsigned char sha1[20];
246                         struct stat st;
247                         int flag;
248                         int namelen;
249
250                         if (de->d_name[0] == '.')
251                                 continue;
252                         namelen = strlen(de->d_name);
253                         if (namelen > 255)
254                                 continue;
255                         if (has_extension(de->d_name, ".lock"))
256                                 continue;
257                         memcpy(ref + baselen, de->d_name, namelen+1);
258                         if (stat(git_path("%s", ref), &st) < 0)
259                                 continue;
260                         if (S_ISDIR(st.st_mode)) {
261                                 list = get_ref_dir(ref, list);
262                                 continue;
263                         }
264                         if (!resolve_ref(ref, sha1, 1, &flag)) {
265                                 error("%s points nowhere!", ref);
266                                 continue;
267                         }
268                         list = add_ref(ref, sha1, flag, list, NULL);
269                 }
270                 free(ref);
271                 closedir(dir);
272         }
273         return sort_ref_list(list);
274 }
275
276 static struct ref_list *get_loose_refs(void)
277 {
278         if (!cached_refs.did_loose) {
279                 cached_refs.loose = get_ref_dir("refs", NULL);
280                 cached_refs.did_loose = 1;
281         }
282         return cached_refs.loose;
283 }
284
285 /* We allow "recursive" symbolic refs. Only within reason, though */
286 #define MAXDEPTH 5
287 #define MAXREFLEN (1024)
288
289 static int resolve_gitlink_packed_ref(char *name, int pathlen, const char *refname, unsigned char *result)
290 {
291         FILE *f;
292         struct cached_refs refs;
293         struct ref_list *ref;
294         int retval;
295
296         strcpy(name + pathlen, "packed-refs");
297         f = fopen(name, "r");
298         if (!f)
299                 return -1;
300         read_packed_refs(f, &refs);
301         fclose(f);
302         ref = refs.packed;
303         retval = -1;
304         while (ref) {
305                 if (!strcmp(ref->name, refname)) {
306                         retval = 0;
307                         memcpy(result, ref->sha1, 20);
308                         break;
309                 }
310                 ref = ref->next;
311         }
312         free_ref_list(refs.packed);
313         return retval;
314 }
315
316 static int resolve_gitlink_ref_recursive(char *name, int pathlen, const char *refname, unsigned char *result, int recursion)
317 {
318         int fd, len = strlen(refname);
319         char buffer[128], *p;
320
321         if (recursion > MAXDEPTH || len > MAXREFLEN)
322                 return -1;
323         memcpy(name + pathlen, refname, len+1);
324         fd = open(name, O_RDONLY);
325         if (fd < 0)
326                 return resolve_gitlink_packed_ref(name, pathlen, refname, result);
327
328         len = read(fd, buffer, sizeof(buffer)-1);
329         close(fd);
330         if (len < 0)
331                 return -1;
332         while (len && isspace(buffer[len-1]))
333                 len--;
334         buffer[len] = 0;
335
336         /* Was it a detached head or an old-fashioned symlink? */
337         if (!get_sha1_hex(buffer, result))
338                 return 0;
339
340         /* Symref? */
341         if (strncmp(buffer, "ref:", 4))
342                 return -1;
343         p = buffer + 4;
344         while (isspace(*p))
345                 p++;
346
347         return resolve_gitlink_ref_recursive(name, pathlen, p, result, recursion+1);
348 }
349
350 int resolve_gitlink_ref(const char *path, const char *refname, unsigned char *result)
351 {
352         int len = strlen(path), retval;
353         char *gitdir;
354
355         while (len && path[len-1] == '/')
356                 len--;
357         if (!len)
358                 return -1;
359         gitdir = xmalloc(len + MAXREFLEN + 8);
360         memcpy(gitdir, path, len);
361         memcpy(gitdir + len, "/.git/", 7);
362
363         retval = resolve_gitlink_ref_recursive(gitdir, len+6, refname, result, 0);
364         free(gitdir);
365         return retval;
366 }
367
368 const char *resolve_ref(const char *ref, unsigned char *sha1, int reading, int *flag)
369 {
370         int depth = MAXDEPTH, len;
371         char buffer[256];
372         static char ref_buffer[256];
373
374         if (flag)
375                 *flag = 0;
376
377         for (;;) {
378                 const char *path = git_path("%s", ref);
379                 struct stat st;
380                 char *buf;
381                 int fd;
382
383                 if (--depth < 0)
384                         return NULL;
385
386                 /* Special case: non-existing file.
387                  * Not having the refs/heads/new-branch is OK
388                  * if we are writing into it, so is .git/HEAD
389                  * that points at refs/heads/master still to be
390                  * born.  It is NOT OK if we are resolving for
391                  * reading.
392                  */
393                 if (lstat(path, &st) < 0) {
394                         struct ref_list *list = get_packed_refs();
395                         while (list) {
396                                 if (!strcmp(ref, list->name)) {
397                                         hashcpy(sha1, list->sha1);
398                                         if (flag)
399                                                 *flag |= REF_ISPACKED;
400                                         return ref;
401                                 }
402                                 list = list->next;
403                         }
404                         if (reading || errno != ENOENT)
405                                 return NULL;
406                         hashclr(sha1);
407                         return ref;
408                 }
409
410                 /* Follow "normalized" - ie "refs/.." symlinks by hand */
411                 if (S_ISLNK(st.st_mode)) {
412                         len = readlink(path, buffer, sizeof(buffer)-1);
413                         if (len >= 5 && !memcmp("refs/", buffer, 5)) {
414                                 buffer[len] = 0;
415                                 strcpy(ref_buffer, buffer);
416                                 ref = ref_buffer;
417                                 if (flag)
418                                         *flag |= REF_ISSYMREF;
419                                 continue;
420                         }
421                 }
422
423                 /* Is it a directory? */
424                 if (S_ISDIR(st.st_mode)) {
425                         errno = EISDIR;
426                         return NULL;
427                 }
428
429                 /*
430                  * Anything else, just open it and try to use it as
431                  * a ref
432                  */
433                 fd = open(path, O_RDONLY);
434                 if (fd < 0)
435                         return NULL;
436                 len = read_in_full(fd, buffer, sizeof(buffer)-1);
437                 close(fd);
438
439                 /*
440                  * Is it a symbolic ref?
441                  */
442                 if (len < 4 || memcmp("ref:", buffer, 4))
443                         break;
444                 buf = buffer + 4;
445                 len -= 4;
446                 while (len && isspace(*buf))
447                         buf++, len--;
448                 while (len && isspace(buf[len-1]))
449                         len--;
450                 buf[len] = 0;
451                 memcpy(ref_buffer, buf, len + 1);
452                 ref = ref_buffer;
453                 if (flag)
454                         *flag |= REF_ISSYMREF;
455         }
456         if (len < 40 || get_sha1_hex(buffer, sha1))
457                 return NULL;
458         return ref;
459 }
460
461 int read_ref(const char *ref, unsigned char *sha1)
462 {
463         if (resolve_ref(ref, sha1, 1, NULL))
464                 return 0;
465         return -1;
466 }
467
468 static int do_one_ref(const char *base, each_ref_fn fn, int trim,
469                       void *cb_data, struct ref_list *entry)
470 {
471         if (strncmp(base, entry->name, trim))
472                 return 0;
473         if (is_null_sha1(entry->sha1))
474                 return 0;
475         if (!has_sha1_file(entry->sha1)) {
476                 error("%s does not point to a valid object!", entry->name);
477                 return 0;
478         }
479         return fn(entry->name + trim, entry->sha1, entry->flag, cb_data);
480 }
481
482 int peel_ref(const char *ref, unsigned char *sha1)
483 {
484         int flag;
485         unsigned char base[20];
486         struct object *o;
487
488         if (!resolve_ref(ref, base, 1, &flag))
489                 return -1;
490
491         if ((flag & REF_ISPACKED)) {
492                 struct ref_list *list = get_packed_refs();
493
494                 while (list) {
495                         if (!strcmp(list->name, ref)) {
496                                 if (list->flag & REF_KNOWS_PEELED) {
497                                         hashcpy(sha1, list->peeled);
498                                         return 0;
499                                 }
500                                 /* older pack-refs did not leave peeled ones */
501                                 break;
502                         }
503                         list = list->next;
504                 }
505         }
506
507         /* fallback - callers should not call this for unpacked refs */
508         o = parse_object(base);
509         if (o->type == OBJ_TAG) {
510                 o = deref_tag(o, ref, 0);
511                 if (o) {
512                         hashcpy(sha1, o->sha1);
513                         return 0;
514                 }
515         }
516         return -1;
517 }
518
519 static int do_for_each_ref(const char *base, each_ref_fn fn, int trim,
520                            void *cb_data)
521 {
522         int retval;
523         struct ref_list *packed = get_packed_refs();
524         struct ref_list *loose = get_loose_refs();
525
526         while (packed && loose) {
527                 struct ref_list *entry;
528                 int cmp = strcmp(packed->name, loose->name);
529                 if (!cmp) {
530                         packed = packed->next;
531                         continue;
532                 }
533                 if (cmp > 0) {
534                         entry = loose;
535                         loose = loose->next;
536                 } else {
537                         entry = packed;
538                         packed = packed->next;
539                 }
540                 retval = do_one_ref(base, fn, trim, cb_data, entry);
541                 if (retval)
542                         return retval;
543         }
544
545         for (packed = packed ? packed : loose; packed; packed = packed->next) {
546                 retval = do_one_ref(base, fn, trim, cb_data, packed);
547                 if (retval)
548                         return retval;
549         }
550         return 0;
551 }
552
553 int head_ref(each_ref_fn fn, void *cb_data)
554 {
555         unsigned char sha1[20];
556         int flag;
557
558         if (resolve_ref("HEAD", sha1, 1, &flag))
559                 return fn("HEAD", sha1, flag, cb_data);
560         return 0;
561 }
562
563 int for_each_ref(each_ref_fn fn, void *cb_data)
564 {
565         return do_for_each_ref("refs/", fn, 0, cb_data);
566 }
567
568 int for_each_tag_ref(each_ref_fn fn, void *cb_data)
569 {
570         return do_for_each_ref("refs/tags/", fn, 10, cb_data);
571 }
572
573 int for_each_branch_ref(each_ref_fn fn, void *cb_data)
574 {
575         return do_for_each_ref("refs/heads/", fn, 11, cb_data);
576 }
577
578 int for_each_remote_ref(each_ref_fn fn, void *cb_data)
579 {
580         return do_for_each_ref("refs/remotes/", fn, 13, cb_data);
581 }
582
583 /*
584  * Make sure "ref" is something reasonable to have under ".git/refs/";
585  * We do not like it if:
586  *
587  * - any path component of it begins with ".", or
588  * - it has double dots "..", or
589  * - it has ASCII control character, "~", "^", ":" or SP, anywhere, or
590  * - it ends with a "/".
591  */
592
593 static inline int bad_ref_char(int ch)
594 {
595         if (((unsigned) ch) <= ' ' ||
596             ch == '~' || ch == '^' || ch == ':')
597                 return 1;
598         /* 2.13 Pattern Matching Notation */
599         if (ch == '?' || ch == '[') /* Unsupported */
600                 return 1;
601         if (ch == '*') /* Supported at the end */
602                 return 2;
603         return 0;
604 }
605
606 int check_ref_format(const char *ref)
607 {
608         int ch, level, bad_type;
609         const char *cp = ref;
610
611         level = 0;
612         while (1) {
613                 while ((ch = *cp++) == '/')
614                         ; /* tolerate duplicated slashes */
615                 if (!ch)
616                         return -1; /* should not end with slashes */
617
618                 /* we are at the beginning of the path component */
619                 if (ch == '.')
620                         return -1;
621                 bad_type = bad_ref_char(ch);
622                 if (bad_type) {
623                         return (bad_type == 2 && !*cp) ? -3 : -1;
624                 }
625
626                 /* scan the rest of the path component */
627                 while ((ch = *cp++) != 0) {
628                         bad_type = bad_ref_char(ch);
629                         if (bad_type) {
630                                 return (bad_type == 2 && !*cp) ? -3 : -1;
631                         }
632                         if (ch == '/')
633                                 break;
634                         if (ch == '.' && *cp == '.')
635                                 return -1;
636                 }
637                 level++;
638                 if (!ch) {
639                         if (level < 2)
640                                 return -2; /* at least of form "heads/blah" */
641                         return 0;
642                 }
643         }
644 }
645
646 static struct ref_lock *verify_lock(struct ref_lock *lock,
647         const unsigned char *old_sha1, int mustexist)
648 {
649         if (!resolve_ref(lock->ref_name, lock->old_sha1, mustexist, NULL)) {
650                 error("Can't verify ref %s", lock->ref_name);
651                 unlock_ref(lock);
652                 return NULL;
653         }
654         if (hashcmp(lock->old_sha1, old_sha1)) {
655                 error("Ref %s is at %s but expected %s", lock->ref_name,
656                         sha1_to_hex(lock->old_sha1), sha1_to_hex(old_sha1));
657                 unlock_ref(lock);
658                 return NULL;
659         }
660         return lock;
661 }
662
663 static int remove_empty_directories(const char *file)
664 {
665         /* we want to create a file but there is a directory there;
666          * if that is an empty directory (or a directory that contains
667          * only empty directories), remove them.
668          */
669         struct strbuf path;
670         int result;
671
672         strbuf_init(&path, 20);
673         strbuf_addstr(&path, file);
674
675         result = remove_dir_recursively(&path, 1);
676
677         strbuf_release(&path);
678
679         return result;
680 }
681
682 static int is_refname_available(const char *ref, const char *oldref,
683                                 struct ref_list *list, int quiet)
684 {
685         int namlen = strlen(ref); /* e.g. 'foo/bar' */
686         while (list) {
687                 /* list->name could be 'foo' or 'foo/bar/baz' */
688                 if (!oldref || strcmp(oldref, list->name)) {
689                         int len = strlen(list->name);
690                         int cmplen = (namlen < len) ? namlen : len;
691                         const char *lead = (namlen < len) ? list->name : ref;
692                         if (!strncmp(ref, list->name, cmplen) &&
693                             lead[cmplen] == '/') {
694                                 if (!quiet)
695                                         error("'%s' exists; cannot create '%s'",
696                                               list->name, ref);
697                                 return 0;
698                         }
699                 }
700                 list = list->next;
701         }
702         return 1;
703 }
704
705 static struct ref_lock *lock_ref_sha1_basic(const char *ref, const unsigned char *old_sha1, int flags, int *type_p)
706 {
707         char *ref_file;
708         const char *orig_ref = ref;
709         struct ref_lock *lock;
710         struct stat st;
711         int last_errno = 0;
712         int type;
713         int mustexist = (old_sha1 && !is_null_sha1(old_sha1));
714
715         lock = xcalloc(1, sizeof(struct ref_lock));
716         lock->lock_fd = -1;
717
718         ref = resolve_ref(ref, lock->old_sha1, mustexist, &type);
719         if (!ref && errno == EISDIR) {
720                 /* we are trying to lock foo but we used to
721                  * have foo/bar which now does not exist;
722                  * it is normal for the empty directory 'foo'
723                  * to remain.
724                  */
725                 ref_file = git_path("%s", orig_ref);
726                 if (remove_empty_directories(ref_file)) {
727                         last_errno = errno;
728                         error("there are still refs under '%s'", orig_ref);
729                         goto error_return;
730                 }
731                 ref = resolve_ref(orig_ref, lock->old_sha1, mustexist, &type);
732         }
733         if (type_p)
734             *type_p = type;
735         if (!ref) {
736                 last_errno = errno;
737                 error("unable to resolve reference %s: %s",
738                         orig_ref, strerror(errno));
739                 goto error_return;
740         }
741         /* When the ref did not exist and we are creating it,
742          * make sure there is no existing ref that is packed
743          * whose name begins with our refname, nor a ref whose
744          * name is a proper prefix of our refname.
745          */
746         if (is_null_sha1(lock->old_sha1) &&
747             !is_refname_available(ref, NULL, get_packed_refs(), 0))
748                 goto error_return;
749
750         lock->lk = xcalloc(1, sizeof(struct lock_file));
751
752         if (flags & REF_NODEREF)
753                 ref = orig_ref;
754         lock->ref_name = xstrdup(ref);
755         lock->orig_ref_name = xstrdup(orig_ref);
756         ref_file = git_path("%s", ref);
757         if (lstat(ref_file, &st) && errno == ENOENT)
758                 lock->force_write = 1;
759         if ((flags & REF_NODEREF) && (type & REF_ISSYMREF))
760                 lock->force_write = 1;
761
762         if (safe_create_leading_directories(ref_file)) {
763                 last_errno = errno;
764                 error("unable to create directory for %s", ref_file);
765                 goto error_return;
766         }
767         lock->lock_fd = hold_lock_file_for_update(lock->lk, ref_file, 1);
768
769         return old_sha1 ? verify_lock(lock, old_sha1, mustexist) : lock;
770
771  error_return:
772         unlock_ref(lock);
773         errno = last_errno;
774         return NULL;
775 }
776
777 struct ref_lock *lock_ref_sha1(const char *ref, const unsigned char *old_sha1)
778 {
779         char refpath[PATH_MAX];
780         if (check_ref_format(ref))
781                 return NULL;
782         strcpy(refpath, mkpath("refs/%s", ref));
783         return lock_ref_sha1_basic(refpath, old_sha1, 0, NULL);
784 }
785
786 struct ref_lock *lock_any_ref_for_update(const char *ref, const unsigned char *old_sha1, int flags)
787 {
788         if (check_ref_format(ref) == -1)
789                 return NULL;
790         return lock_ref_sha1_basic(ref, old_sha1, flags, NULL);
791 }
792
793 static struct lock_file packlock;
794
795 static int repack_without_ref(const char *refname)
796 {
797         struct ref_list *list, *packed_ref_list;
798         int fd;
799         int found = 0;
800
801         packed_ref_list = get_packed_refs();
802         for (list = packed_ref_list; list; list = list->next) {
803                 if (!strcmp(refname, list->name)) {
804                         found = 1;
805                         break;
806                 }
807         }
808         if (!found)
809                 return 0;
810         fd = hold_lock_file_for_update(&packlock, git_path("packed-refs"), 0);
811         if (fd < 0)
812                 return error("cannot delete '%s' from packed refs", refname);
813
814         for (list = packed_ref_list; list; list = list->next) {
815                 char line[PATH_MAX + 100];
816                 int len;
817
818                 if (!strcmp(refname, list->name))
819                         continue;
820                 len = snprintf(line, sizeof(line), "%s %s\n",
821                                sha1_to_hex(list->sha1), list->name);
822                 /* this should not happen but just being defensive */
823                 if (len > sizeof(line))
824                         die("too long a refname '%s'", list->name);
825                 write_or_die(fd, line, len);
826         }
827         close(fd);
828         return commit_lock_file(&packlock);
829 }
830
831 int delete_ref(const char *refname, const unsigned char *sha1)
832 {
833         struct ref_lock *lock;
834         int err, i, ret = 0, flag = 0;
835
836         lock = lock_ref_sha1_basic(refname, sha1, 0, &flag);
837         if (!lock)
838                 return 1;
839         if (!(flag & REF_ISPACKED)) {
840                 /* loose */
841                 i = strlen(lock->lk->filename) - 5; /* .lock */
842                 lock->lk->filename[i] = 0;
843                 err = unlink(lock->lk->filename);
844                 if (err) {
845                         ret = 1;
846                         error("unlink(%s) failed: %s",
847                               lock->lk->filename, strerror(errno));
848                 }
849                 lock->lk->filename[i] = '.';
850         }
851         /* removing the loose one could have resurrected an earlier
852          * packed one.  Also, if it was not loose we need to repack
853          * without it.
854          */
855         ret |= repack_without_ref(refname);
856
857         err = unlink(git_path("logs/%s", lock->ref_name));
858         if (err && errno != ENOENT)
859                 fprintf(stderr, "warning: unlink(%s) failed: %s",
860                         git_path("logs/%s", lock->ref_name), strerror(errno));
861         invalidate_cached_refs();
862         unlock_ref(lock);
863         return ret;
864 }
865
866 int rename_ref(const char *oldref, const char *newref, const char *logmsg)
867 {
868         static const char renamed_ref[] = "RENAMED-REF";
869         unsigned char sha1[20], orig_sha1[20];
870         int flag = 0, logmoved = 0;
871         struct ref_lock *lock;
872         struct stat loginfo;
873         int log = !lstat(git_path("logs/%s", oldref), &loginfo);
874
875         if (S_ISLNK(loginfo.st_mode))
876                 return error("reflog for %s is a symlink", oldref);
877
878         if (!resolve_ref(oldref, orig_sha1, 1, &flag))
879                 return error("refname %s not found", oldref);
880
881         if (!is_refname_available(newref, oldref, get_packed_refs(), 0))
882                 return 1;
883
884         if (!is_refname_available(newref, oldref, get_loose_refs(), 0))
885                 return 1;
886
887         lock = lock_ref_sha1_basic(renamed_ref, NULL, 0, NULL);
888         if (!lock)
889                 return error("unable to lock %s", renamed_ref);
890         lock->force_write = 1;
891         if (write_ref_sha1(lock, orig_sha1, logmsg))
892                 return error("unable to save current sha1 in %s", renamed_ref);
893
894         if (log && rename(git_path("logs/%s", oldref), git_path("tmp-renamed-log")))
895                 return error("unable to move logfile logs/%s to tmp-renamed-log: %s",
896                         oldref, strerror(errno));
897
898         if (delete_ref(oldref, orig_sha1)) {
899                 error("unable to delete old %s", oldref);
900                 goto rollback;
901         }
902
903         if (resolve_ref(newref, sha1, 1, &flag) && delete_ref(newref, sha1)) {
904                 if (errno==EISDIR) {
905                         if (remove_empty_directories(git_path("%s", newref))) {
906                                 error("Directory not empty: %s", newref);
907                                 goto rollback;
908                         }
909                 } else {
910                         error("unable to delete existing %s", newref);
911                         goto rollback;
912                 }
913         }
914
915         if (log && safe_create_leading_directories(git_path("logs/%s", newref))) {
916                 error("unable to create directory for %s", newref);
917                 goto rollback;
918         }
919
920  retry:
921         if (log && rename(git_path("tmp-renamed-log"), git_path("logs/%s", newref))) {
922                 if (errno==EISDIR || errno==ENOTDIR) {
923                         /*
924                          * rename(a, b) when b is an existing
925                          * directory ought to result in ISDIR, but
926                          * Solaris 5.8 gives ENOTDIR.  Sheesh.
927                          */
928                         if (remove_empty_directories(git_path("logs/%s", newref))) {
929                                 error("Directory not empty: logs/%s", newref);
930                                 goto rollback;
931                         }
932                         goto retry;
933                 } else {
934                         error("unable to move logfile tmp-renamed-log to logs/%s: %s",
935                                 newref, strerror(errno));
936                         goto rollback;
937                 }
938         }
939         logmoved = log;
940
941         lock = lock_ref_sha1_basic(newref, NULL, 0, NULL);
942         if (!lock) {
943                 error("unable to lock %s for update", newref);
944                 goto rollback;
945         }
946
947         lock->force_write = 1;
948         hashcpy(lock->old_sha1, orig_sha1);
949         if (write_ref_sha1(lock, orig_sha1, logmsg)) {
950                 error("unable to write current sha1 into %s", newref);
951                 goto rollback;
952         }
953
954         return 0;
955
956  rollback:
957         lock = lock_ref_sha1_basic(oldref, NULL, 0, NULL);
958         if (!lock) {
959                 error("unable to lock %s for rollback", oldref);
960                 goto rollbacklog;
961         }
962
963         lock->force_write = 1;
964         flag = log_all_ref_updates;
965         log_all_ref_updates = 0;
966         if (write_ref_sha1(lock, orig_sha1, NULL))
967                 error("unable to write current sha1 into %s", oldref);
968         log_all_ref_updates = flag;
969
970  rollbacklog:
971         if (logmoved && rename(git_path("logs/%s", newref), git_path("logs/%s", oldref)))
972                 error("unable to restore logfile %s from %s: %s",
973                         oldref, newref, strerror(errno));
974         if (!logmoved && log &&
975             rename(git_path("tmp-renamed-log"), git_path("logs/%s", oldref)))
976                 error("unable to restore logfile %s from tmp-renamed-log: %s",
977                         oldref, strerror(errno));
978
979         return 1;
980 }
981
982 void unlock_ref(struct ref_lock *lock)
983 {
984         if (lock->lock_fd >= 0) {
985                 close(lock->lock_fd);
986                 /* Do not free lock->lk -- atexit() still looks at them */
987                 if (lock->lk)
988                         rollback_lock_file(lock->lk);
989         }
990         free(lock->ref_name);
991         free(lock->orig_ref_name);
992         free(lock);
993 }
994
995 /*
996  * copy the reflog message msg to buf, which has been allocated sufficiently
997  * large, while cleaning up the whitespaces.  Especially, convert LF to space,
998  * because reflog file is one line per entry.
999  */
1000 static int copy_msg(char *buf, const char *msg)
1001 {
1002         char *cp = buf;
1003         char c;
1004         int wasspace = 1;
1005
1006         *cp++ = '\t';
1007         while ((c = *msg++)) {
1008                 if (wasspace && isspace(c))
1009                         continue;
1010                 wasspace = isspace(c);
1011                 if (wasspace)
1012                         c = ' ';
1013                 *cp++ = c;
1014         }
1015         while (buf < cp && isspace(cp[-1]))
1016                 cp--;
1017         *cp++ = '\n';
1018         return cp - buf;
1019 }
1020
1021 static int log_ref_write(const char *ref_name, const unsigned char *old_sha1,
1022                          const unsigned char *new_sha1, const char *msg)
1023 {
1024         int logfd, written, oflags = O_APPEND | O_WRONLY;
1025         unsigned maxlen, len;
1026         int msglen;
1027         char *log_file, *logrec;
1028         const char *committer;
1029
1030         if (log_all_ref_updates < 0)
1031                 log_all_ref_updates = !is_bare_repository();
1032
1033         log_file = git_path("logs/%s", ref_name);
1034
1035         if (log_all_ref_updates &&
1036             (!prefixcmp(ref_name, "refs/heads/") ||
1037              !prefixcmp(ref_name, "refs/remotes/") ||
1038              !strcmp(ref_name, "HEAD"))) {
1039                 if (safe_create_leading_directories(log_file) < 0)
1040                         return error("unable to create directory for %s",
1041                                      log_file);
1042                 oflags |= O_CREAT;
1043         }
1044
1045         logfd = open(log_file, oflags, 0666);
1046         if (logfd < 0) {
1047                 if (!(oflags & O_CREAT) && errno == ENOENT)
1048                         return 0;
1049
1050                 if ((oflags & O_CREAT) && errno == EISDIR) {
1051                         if (remove_empty_directories(log_file)) {
1052                                 return error("There are still logs under '%s'",
1053                                              log_file);
1054                         }
1055                         logfd = open(log_file, oflags, 0666);
1056                 }
1057
1058                 if (logfd < 0)
1059                         return error("Unable to append to %s: %s",
1060                                      log_file, strerror(errno));
1061         }
1062
1063         adjust_shared_perm(log_file);
1064
1065         msglen = msg ? strlen(msg) : 0;
1066         committer = git_committer_info(-1);
1067         maxlen = strlen(committer) + msglen + 100;
1068         logrec = xmalloc(maxlen);
1069         len = sprintf(logrec, "%s %s %s\n",
1070                       sha1_to_hex(old_sha1),
1071                       sha1_to_hex(new_sha1),
1072                       committer);
1073         if (msglen)
1074                 len += copy_msg(logrec + len - 1, msg) - 1;
1075         written = len <= maxlen ? write_in_full(logfd, logrec, len) : -1;
1076         free(logrec);
1077         if (close(logfd) != 0 || written != len)
1078                 return error("Unable to append to %s", log_file);
1079         return 0;
1080 }
1081
1082 int write_ref_sha1(struct ref_lock *lock,
1083         const unsigned char *sha1, const char *logmsg)
1084 {
1085         static char term = '\n';
1086
1087         if (!lock)
1088                 return -1;
1089         if (!lock->force_write && !hashcmp(lock->old_sha1, sha1)) {
1090                 unlock_ref(lock);
1091                 return 0;
1092         }
1093         if (write_in_full(lock->lock_fd, sha1_to_hex(sha1), 40) != 40 ||
1094             write_in_full(lock->lock_fd, &term, 1) != 1
1095                 || close(lock->lock_fd) < 0) {
1096                 error("Couldn't write %s", lock->lk->filename);
1097                 unlock_ref(lock);
1098                 return -1;
1099         }
1100         invalidate_cached_refs();
1101         if (log_ref_write(lock->ref_name, lock->old_sha1, sha1, logmsg) < 0 ||
1102             (strcmp(lock->ref_name, lock->orig_ref_name) &&
1103              log_ref_write(lock->orig_ref_name, lock->old_sha1, sha1, logmsg) < 0)) {
1104                 unlock_ref(lock);
1105                 return -1;
1106         }
1107         if (strcmp(lock->orig_ref_name, "HEAD") != 0) {
1108                 /*
1109                  * Special hack: If a branch is updated directly and HEAD
1110                  * points to it (may happen on the remote side of a push
1111                  * for example) then logically the HEAD reflog should be
1112                  * updated too.
1113                  * A generic solution implies reverse symref information,
1114                  * but finding all symrefs pointing to the given branch
1115                  * would be rather costly for this rare event (the direct
1116                  * update of a branch) to be worth it.  So let's cheat and
1117                  * check with HEAD only which should cover 99% of all usage
1118                  * scenarios (even 100% of the default ones).
1119                  */
1120                 unsigned char head_sha1[20];
1121                 int head_flag;
1122                 const char *head_ref;
1123                 head_ref = resolve_ref("HEAD", head_sha1, 1, &head_flag);
1124                 if (head_ref && (head_flag & REF_ISSYMREF) &&
1125                     !strcmp(head_ref, lock->ref_name))
1126                         log_ref_write("HEAD", lock->old_sha1, sha1, logmsg);
1127         }
1128         if (commit_lock_file(lock->lk)) {
1129                 error("Couldn't set %s", lock->ref_name);
1130                 unlock_ref(lock);
1131                 return -1;
1132         }
1133         lock->lock_fd = -1;
1134         unlock_ref(lock);
1135         return 0;
1136 }
1137
1138 int create_symref(const char *ref_target, const char *refs_heads_master,
1139                   const char *logmsg)
1140 {
1141         const char *lockpath;
1142         char ref[1000];
1143         int fd, len, written;
1144         char *git_HEAD = xstrdup(git_path("%s", ref_target));
1145         unsigned char old_sha1[20], new_sha1[20];
1146
1147         if (logmsg && read_ref(ref_target, old_sha1))
1148                 hashclr(old_sha1);
1149
1150         if (safe_create_leading_directories(git_HEAD) < 0)
1151                 return error("unable to create directory for %s", git_HEAD);
1152
1153 #ifndef NO_SYMLINK_HEAD
1154         if (prefer_symlink_refs) {
1155                 unlink(git_HEAD);
1156                 if (!symlink(refs_heads_master, git_HEAD))
1157                         goto done;
1158                 fprintf(stderr, "no symlink - falling back to symbolic ref\n");
1159         }
1160 #endif
1161
1162         len = snprintf(ref, sizeof(ref), "ref: %s\n", refs_heads_master);
1163         if (sizeof(ref) <= len) {
1164                 error("refname too long: %s", refs_heads_master);
1165                 goto error_free_return;
1166         }
1167         lockpath = mkpath("%s.lock", git_HEAD);
1168         fd = open(lockpath, O_CREAT | O_EXCL | O_WRONLY, 0666);
1169         if (fd < 0) {
1170                 error("Unable to open %s for writing", lockpath);
1171                 goto error_free_return;
1172         }
1173         written = write_in_full(fd, ref, len);
1174         if (close(fd) != 0 || written != len) {
1175                 error("Unable to write to %s", lockpath);
1176                 goto error_unlink_return;
1177         }
1178         if (rename(lockpath, git_HEAD) < 0) {
1179                 error("Unable to create %s", git_HEAD);
1180                 goto error_unlink_return;
1181         }
1182         if (adjust_shared_perm(git_HEAD)) {
1183                 error("Unable to fix permissions on %s", lockpath);
1184         error_unlink_return:
1185                 unlink(lockpath);
1186         error_free_return:
1187                 free(git_HEAD);
1188                 return -1;
1189         }
1190
1191 #ifndef NO_SYMLINK_HEAD
1192         done:
1193 #endif
1194         if (logmsg && !read_ref(refs_heads_master, new_sha1))
1195                 log_ref_write(ref_target, old_sha1, new_sha1, logmsg);
1196
1197         free(git_HEAD);
1198         return 0;
1199 }
1200
1201 static char *ref_msg(const char *line, const char *endp)
1202 {
1203         const char *ep;
1204         line += 82;
1205         ep = memchr(line, '\n', endp - line);
1206         if (!ep)
1207                 ep = endp;
1208         return xmemdupz(line, ep - line);
1209 }
1210
1211 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)
1212 {
1213         const char *logfile, *logdata, *logend, *rec, *lastgt, *lastrec;
1214         char *tz_c;
1215         int logfd, tz, reccnt = 0;
1216         struct stat st;
1217         unsigned long date;
1218         unsigned char logged_sha1[20];
1219         void *log_mapped;
1220         size_t mapsz;
1221
1222         logfile = git_path("logs/%s", ref);
1223         logfd = open(logfile, O_RDONLY, 0);
1224         if (logfd < 0)
1225                 die("Unable to read log %s: %s", logfile, strerror(errno));
1226         fstat(logfd, &st);
1227         if (!st.st_size)
1228                 die("Log %s is empty.", logfile);
1229         mapsz = xsize_t(st.st_size);
1230         log_mapped = xmmap(NULL, mapsz, PROT_READ, MAP_PRIVATE, logfd, 0);
1231         logdata = log_mapped;
1232         close(logfd);
1233
1234         lastrec = NULL;
1235         rec = logend = logdata + st.st_size;
1236         while (logdata < rec) {
1237                 reccnt++;
1238                 if (logdata < rec && *(rec-1) == '\n')
1239                         rec--;
1240                 lastgt = NULL;
1241                 while (logdata < rec && *(rec-1) != '\n') {
1242                         rec--;
1243                         if (*rec == '>')
1244                                 lastgt = rec;
1245                 }
1246                 if (!lastgt)
1247                         die("Log %s is corrupt.", logfile);
1248                 date = strtoul(lastgt + 1, &tz_c, 10);
1249                 if (date <= at_time || cnt == 0) {
1250                         tz = strtoul(tz_c, NULL, 10);
1251                         if (msg)
1252                                 *msg = ref_msg(rec, logend);
1253                         if (cutoff_time)
1254                                 *cutoff_time = date;
1255                         if (cutoff_tz)
1256                                 *cutoff_tz = tz;
1257                         if (cutoff_cnt)
1258                                 *cutoff_cnt = reccnt - 1;
1259                         if (lastrec) {
1260                                 if (get_sha1_hex(lastrec, logged_sha1))
1261                                         die("Log %s is corrupt.", logfile);
1262                                 if (get_sha1_hex(rec + 41, sha1))
1263                                         die("Log %s is corrupt.", logfile);
1264                                 if (hashcmp(logged_sha1, sha1)) {
1265                                         fprintf(stderr,
1266                                                 "warning: Log %s has gap after %s.\n",
1267                                                 logfile, show_date(date, tz, DATE_RFC2822));
1268                                 }
1269                         }
1270                         else if (date == at_time) {
1271                                 if (get_sha1_hex(rec + 41, sha1))
1272                                         die("Log %s is corrupt.", logfile);
1273                         }
1274                         else {
1275                                 if (get_sha1_hex(rec + 41, logged_sha1))
1276                                         die("Log %s is corrupt.", logfile);
1277                                 if (hashcmp(logged_sha1, sha1)) {
1278                                         fprintf(stderr,
1279                                                 "warning: Log %s unexpectedly ended on %s.\n",
1280                                                 logfile, show_date(date, tz, DATE_RFC2822));
1281                                 }
1282                         }
1283                         munmap(log_mapped, mapsz);
1284                         return 0;
1285                 }
1286                 lastrec = rec;
1287                 if (cnt > 0)
1288                         cnt--;
1289         }
1290
1291         rec = logdata;
1292         while (rec < logend && *rec != '>' && *rec != '\n')
1293                 rec++;
1294         if (rec == logend || *rec == '\n')
1295                 die("Log %s is corrupt.", logfile);
1296         date = strtoul(rec + 1, &tz_c, 10);
1297         tz = strtoul(tz_c, NULL, 10);
1298         if (get_sha1_hex(logdata, sha1))
1299                 die("Log %s is corrupt.", logfile);
1300         if (msg)
1301                 *msg = ref_msg(logdata, logend);
1302         munmap(log_mapped, mapsz);
1303
1304         if (cutoff_time)
1305                 *cutoff_time = date;
1306         if (cutoff_tz)
1307                 *cutoff_tz = tz;
1308         if (cutoff_cnt)
1309                 *cutoff_cnt = reccnt;
1310         return 1;
1311 }
1312
1313 int for_each_reflog_ent(const char *ref, each_reflog_ent_fn fn, void *cb_data)
1314 {
1315         const char *logfile;
1316         FILE *logfp;
1317         char buf[1024];
1318         int ret = 0;
1319
1320         logfile = git_path("logs/%s", ref);
1321         logfp = fopen(logfile, "r");
1322         if (!logfp)
1323                 return -1;
1324         while (fgets(buf, sizeof(buf), logfp)) {
1325                 unsigned char osha1[20], nsha1[20];
1326                 char *email_end, *message;
1327                 unsigned long timestamp;
1328                 int len, tz;
1329
1330                 /* old SP new SP name <email> SP time TAB msg LF */
1331                 len = strlen(buf);
1332                 if (len < 83 || buf[len-1] != '\n' ||
1333                     get_sha1_hex(buf, osha1) || buf[40] != ' ' ||
1334                     get_sha1_hex(buf + 41, nsha1) || buf[81] != ' ' ||
1335                     !(email_end = strchr(buf + 82, '>')) ||
1336                     email_end[1] != ' ' ||
1337                     !(timestamp = strtoul(email_end + 2, &message, 10)) ||
1338                     !message || message[0] != ' ' ||
1339                     (message[1] != '+' && message[1] != '-') ||
1340                     !isdigit(message[2]) || !isdigit(message[3]) ||
1341                     !isdigit(message[4]) || !isdigit(message[5]))
1342                         continue; /* corrupt? */
1343                 email_end[1] = '\0';
1344                 tz = strtol(message + 1, NULL, 10);
1345                 if (message[6] != '\t')
1346                         message += 6;
1347                 else
1348                         message += 7;
1349                 ret = fn(osha1, nsha1, buf+82, timestamp, tz, message, cb_data);
1350                 if (ret)
1351                         break;
1352         }
1353         fclose(logfp);
1354         return ret;
1355 }
1356
1357 static int do_for_each_reflog(const char *base, each_ref_fn fn, void *cb_data)
1358 {
1359         DIR *dir = opendir(git_path("logs/%s", base));
1360         int retval = 0;
1361
1362         if (dir) {
1363                 struct dirent *de;
1364                 int baselen = strlen(base);
1365                 char *log = xmalloc(baselen + 257);
1366
1367                 memcpy(log, base, baselen);
1368                 if (baselen && base[baselen-1] != '/')
1369                         log[baselen++] = '/';
1370
1371                 while ((de = readdir(dir)) != NULL) {
1372                         struct stat st;
1373                         int namelen;
1374
1375                         if (de->d_name[0] == '.')
1376                                 continue;
1377                         namelen = strlen(de->d_name);
1378                         if (namelen > 255)
1379                                 continue;
1380                         if (has_extension(de->d_name, ".lock"))
1381                                 continue;
1382                         memcpy(log + baselen, de->d_name, namelen+1);
1383                         if (stat(git_path("logs/%s", log), &st) < 0)
1384                                 continue;
1385                         if (S_ISDIR(st.st_mode)) {
1386                                 retval = do_for_each_reflog(log, fn, cb_data);
1387                         } else {
1388                                 unsigned char sha1[20];
1389                                 if (!resolve_ref(log, sha1, 0, NULL))
1390                                         retval = error("bad ref for %s", log);
1391                                 else
1392                                         retval = fn(log, sha1, 0, cb_data);
1393                         }
1394                         if (retval)
1395                                 break;
1396                 }
1397                 free(log);
1398                 closedir(dir);
1399         }
1400         else if (*base)
1401                 return errno;
1402         return retval;
1403 }
1404
1405 int for_each_reflog(each_ref_fn fn, void *cb_data)
1406 {
1407         return do_for_each_reflog("", fn, cb_data);
1408 }
1409
1410 int update_ref(const char *action, const char *refname,
1411                 const unsigned char *sha1, const unsigned char *oldval,
1412                 int flags, enum action_on_err onerr)
1413 {
1414         static struct ref_lock *lock;
1415         lock = lock_any_ref_for_update(refname, oldval, flags);
1416         if (!lock) {
1417                 const char *str = "Cannot lock the ref '%s'.";
1418                 switch (onerr) {
1419                 case MSG_ON_ERR: error(str, refname); break;
1420                 case DIE_ON_ERR: die(str, refname); break;
1421                 case QUIET_ON_ERR: break;
1422                 }
1423                 return 1;
1424         }
1425         if (write_ref_sha1(lock, sha1, action) < 0) {
1426                 const char *str = "Cannot update the ref '%s'.";
1427                 switch (onerr) {
1428                 case MSG_ON_ERR: error(str, refname); break;
1429                 case DIE_ON_ERR: die(str, refname); break;
1430                 case QUIET_ON_ERR: break;
1431                 }
1432                 return 1;
1433         }
1434         return 0;
1435 }
1436
1437 struct ref *find_ref_by_name(struct ref *list, const char *name)
1438 {
1439         for ( ; list; list = list->next)
1440                 if (!strcmp(list->name, name))
1441                         return list;
1442         return NULL;
1443 }