Merge branch 'dg/document-git-c-in-git-config-doc' into maint
[git] / builtin / fsck.c
1 #include "builtin.h"
2 #include "cache.h"
3 #include "commit.h"
4 #include "tree.h"
5 #include "blob.h"
6 #include "tag.h"
7 #include "refs.h"
8 #include "pack.h"
9 #include "cache-tree.h"
10 #include "tree-walk.h"
11 #include "fsck.h"
12 #include "parse-options.h"
13 #include "dir.h"
14 #include "progress.h"
15 #include "streaming.h"
16
17 #define REACHABLE 0x0001
18 #define SEEN      0x0002
19 #define HAS_OBJ   0x0004
20
21 static int show_root;
22 static int show_tags;
23 static int show_unreachable;
24 static int include_reflogs = 1;
25 static int check_full = 1;
26 static int connectivity_only;
27 static int check_strict;
28 static int keep_cache_objects;
29 static struct fsck_options fsck_walk_options = FSCK_OPTIONS_DEFAULT;
30 static struct fsck_options fsck_obj_options = FSCK_OPTIONS_DEFAULT;
31 static struct object_id head_oid;
32 static const char *head_points_at;
33 static int errors_found;
34 static int write_lost_and_found;
35 static int verbose;
36 static int show_progress = -1;
37 static int show_dangling = 1;
38 #define ERROR_OBJECT 01
39 #define ERROR_REACHABLE 02
40 #define ERROR_PACK 04
41 #define ERROR_REFS 010
42
43 static int fsck_config(const char *var, const char *value, void *cb)
44 {
45         if (strcmp(var, "fsck.skiplist") == 0) {
46                 const char *path;
47                 struct strbuf sb = STRBUF_INIT;
48
49                 if (git_config_pathname(&path, var, value))
50                         return 1;
51                 strbuf_addf(&sb, "skiplist=%s", path);
52                 free((char *)path);
53                 fsck_set_msg_types(&fsck_obj_options, sb.buf);
54                 strbuf_release(&sb);
55                 return 0;
56         }
57
58         if (skip_prefix(var, "fsck.", &var)) {
59                 fsck_set_msg_type(&fsck_obj_options, var, value);
60                 return 0;
61         }
62
63         return git_default_config(var, value, cb);
64 }
65
66 static void objreport(struct object *obj, const char *msg_type,
67                         const char *err)
68 {
69         fprintf(stderr, "%s in %s %s: %s\n",
70                 msg_type, typename(obj->type), oid_to_hex(&obj->oid), err);
71 }
72
73 static int objerror(struct object *obj, const char *err)
74 {
75         errors_found |= ERROR_OBJECT;
76         objreport(obj, "error", err);
77         return -1;
78 }
79
80 static int fsck_error_func(struct object *obj, int type, const char *message)
81 {
82         objreport(obj, (type == FSCK_WARN) ? "warning" : "error", message);
83         return (type == FSCK_WARN) ? 0 : 1;
84 }
85
86 static struct object_array pending;
87
88 static int mark_object(struct object *obj, int type, void *data, struct fsck_options *options)
89 {
90         struct object *parent = data;
91
92         /*
93          * The only case data is NULL or type is OBJ_ANY is when
94          * mark_object_reachable() calls us.  All the callers of
95          * that function has non-NULL obj hence ...
96          */
97         if (!obj) {
98                 /* ... these references to parent->fld are safe here */
99                 printf("broken link from %7s %s\n",
100                            typename(parent->type), oid_to_hex(&parent->oid));
101                 printf("broken link from %7s %s\n",
102                            (type == OBJ_ANY ? "unknown" : typename(type)), "unknown");
103                 errors_found |= ERROR_REACHABLE;
104                 return 1;
105         }
106
107         if (type != OBJ_ANY && obj->type != type)
108                 /* ... and the reference to parent is safe here */
109                 objerror(parent, "wrong object type in link");
110
111         if (obj->flags & REACHABLE)
112                 return 0;
113         obj->flags |= REACHABLE;
114         if (!(obj->flags & HAS_OBJ)) {
115                 if (parent && !has_object_file(&obj->oid)) {
116                         printf("broken link from %7s %s\n",
117                                  typename(parent->type), oid_to_hex(&parent->oid));
118                         printf("              to %7s %s\n",
119                                  typename(obj->type), oid_to_hex(&obj->oid));
120                         errors_found |= ERROR_REACHABLE;
121                 }
122                 return 1;
123         }
124
125         add_object_array(obj, NULL, &pending);
126         return 0;
127 }
128
129 static void mark_object_reachable(struct object *obj)
130 {
131         mark_object(obj, OBJ_ANY, NULL, NULL);
132 }
133
134 static int traverse_one_object(struct object *obj)
135 {
136         int result;
137         struct tree *tree = NULL;
138
139         if (obj->type == OBJ_TREE) {
140                 tree = (struct tree *)obj;
141                 if (parse_tree(tree) < 0)
142                         return 1; /* error already displayed */
143         }
144         result = fsck_walk(obj, obj, &fsck_walk_options);
145         if (tree)
146                 free_tree_buffer(tree);
147         return result;
148 }
149
150 static int traverse_reachable(void)
151 {
152         struct progress *progress = NULL;
153         unsigned int nr = 0;
154         int result = 0;
155         if (show_progress)
156                 progress = start_progress_delay(_("Checking connectivity"), 0, 0, 2);
157         while (pending.nr) {
158                 struct object_array_entry *entry;
159                 struct object *obj;
160
161                 entry = pending.objects + --pending.nr;
162                 obj = entry->item;
163                 result |= traverse_one_object(obj);
164                 display_progress(progress, ++nr);
165         }
166         stop_progress(&progress);
167         return !!result;
168 }
169
170 static int mark_used(struct object *obj, int type, void *data, struct fsck_options *options)
171 {
172         if (!obj)
173                 return 1;
174         obj->used = 1;
175         return 0;
176 }
177
178 /*
179  * Check a single reachable object
180  */
181 static void check_reachable_object(struct object *obj)
182 {
183         /*
184          * We obviously want the object to be parsed,
185          * except if it was in a pack-file and we didn't
186          * do a full fsck
187          */
188         if (!(obj->flags & HAS_OBJ)) {
189                 if (has_sha1_pack(obj->oid.hash))
190                         return; /* it is in pack - forget about it */
191                 if (connectivity_only && has_object_file(&obj->oid))
192                         return;
193                 printf("missing %s %s\n", typename(obj->type), oid_to_hex(&obj->oid));
194                 errors_found |= ERROR_REACHABLE;
195                 return;
196         }
197 }
198
199 /*
200  * Check a single unreachable object
201  */
202 static void check_unreachable_object(struct object *obj)
203 {
204         /*
205          * Missing unreachable object? Ignore it. It's not like
206          * we miss it (since it can't be reached), nor do we want
207          * to complain about it being unreachable (since it does
208          * not exist).
209          */
210         if (!obj->parsed)
211                 return;
212
213         /*
214          * Unreachable object that exists? Show it if asked to,
215          * since this is something that is prunable.
216          */
217         if (show_unreachable) {
218                 printf("unreachable %s %s\n", typename(obj->type), oid_to_hex(&obj->oid));
219                 return;
220         }
221
222         /*
223          * "!used" means that nothing at all points to it, including
224          * other unreachable objects. In other words, it's the "tip"
225          * of some set of unreachable objects, usually a commit that
226          * got dropped.
227          *
228          * Such starting points are more interesting than some random
229          * set of unreachable objects, so we show them even if the user
230          * hasn't asked for _all_ unreachable objects. If you have
231          * deleted a branch by mistake, this is a prime candidate to
232          * start looking at, for example.
233          */
234         if (!obj->used) {
235                 if (show_dangling)
236                         printf("dangling %s %s\n", typename(obj->type),
237                                oid_to_hex(&obj->oid));
238                 if (write_lost_and_found) {
239                         char *filename = git_pathdup("lost-found/%s/%s",
240                                 obj->type == OBJ_COMMIT ? "commit" : "other",
241                                 oid_to_hex(&obj->oid));
242                         FILE *f;
243
244                         if (safe_create_leading_directories_const(filename)) {
245                                 error("Could not create lost-found");
246                                 free(filename);
247                                 return;
248                         }
249                         if (!(f = fopen(filename, "w")))
250                                 die_errno("Could not open '%s'", filename);
251                         if (obj->type == OBJ_BLOB) {
252                                 if (stream_blob_to_fd(fileno(f), obj->oid.hash, NULL, 1))
253                                         die_errno("Could not write '%s'", filename);
254                         } else
255                                 fprintf(f, "%s\n", oid_to_hex(&obj->oid));
256                         if (fclose(f))
257                                 die_errno("Could not finish '%s'",
258                                           filename);
259                         free(filename);
260                 }
261                 return;
262         }
263
264         /*
265          * Otherwise? It's there, it's unreachable, and some other unreachable
266          * object points to it. Ignore it - it's not interesting, and we showed
267          * all the interesting cases above.
268          */
269 }
270
271 static void check_object(struct object *obj)
272 {
273         if (verbose)
274                 fprintf(stderr, "Checking %s\n", oid_to_hex(&obj->oid));
275
276         if (obj->flags & REACHABLE)
277                 check_reachable_object(obj);
278         else
279                 check_unreachable_object(obj);
280 }
281
282 static void check_connectivity(void)
283 {
284         int i, max;
285
286         /* Traverse the pending reachable objects */
287         traverse_reachable();
288
289         /* Look up all the requirements, warn about missing objects.. */
290         max = get_max_object_index();
291         if (verbose)
292                 fprintf(stderr, "Checking connectivity (%d objects)\n", max);
293
294         for (i = 0; i < max; i++) {
295                 struct object *obj = get_indexed_object(i);
296
297                 if (obj)
298                         check_object(obj);
299         }
300 }
301
302 static int fsck_obj(struct object *obj)
303 {
304         if (obj->flags & SEEN)
305                 return 0;
306         obj->flags |= SEEN;
307
308         if (verbose)
309                 fprintf(stderr, "Checking %s %s\n",
310                         typename(obj->type), oid_to_hex(&obj->oid));
311
312         if (fsck_walk(obj, NULL, &fsck_obj_options))
313                 objerror(obj, "broken links");
314         if (fsck_object(obj, NULL, 0, &fsck_obj_options))
315                 return -1;
316
317         if (obj->type == OBJ_TREE) {
318                 struct tree *item = (struct tree *) obj;
319
320                 free_tree_buffer(item);
321         }
322
323         if (obj->type == OBJ_COMMIT) {
324                 struct commit *commit = (struct commit *) obj;
325
326                 free_commit_buffer(commit);
327
328                 if (!commit->parents && show_root)
329                         printf("root %s\n", oid_to_hex(&commit->object.oid));
330         }
331
332         if (obj->type == OBJ_TAG) {
333                 struct tag *tag = (struct tag *) obj;
334
335                 if (show_tags && tag->tagged) {
336                         printf("tagged %s %s", typename(tag->tagged->type), oid_to_hex(&tag->tagged->oid));
337                         printf(" (%s) in %s\n", tag->tag, oid_to_hex(&tag->object.oid));
338                 }
339         }
340
341         return 0;
342 }
343
344 static int fsck_sha1(const unsigned char *sha1)
345 {
346         struct object *obj = parse_object(sha1);
347         if (!obj) {
348                 errors_found |= ERROR_OBJECT;
349                 return error("%s: object corrupt or missing",
350                              sha1_to_hex(sha1));
351         }
352         obj->flags |= HAS_OBJ;
353         return fsck_obj(obj);
354 }
355
356 static int fsck_obj_buffer(const unsigned char *sha1, enum object_type type,
357                            unsigned long size, void *buffer, int *eaten)
358 {
359         /*
360          * Note, buffer may be NULL if type is OBJ_BLOB. See
361          * verify_packfile(), data_valid variable for details.
362          */
363         struct object *obj;
364         obj = parse_object_buffer(sha1, type, size, buffer, eaten);
365         if (!obj) {
366                 errors_found |= ERROR_OBJECT;
367                 return error("%s: object corrupt or missing", sha1_to_hex(sha1));
368         }
369         obj->flags = HAS_OBJ;
370         return fsck_obj(obj);
371 }
372
373 static int default_refs;
374
375 static void fsck_handle_reflog_sha1(const char *refname, unsigned char *sha1)
376 {
377         struct object *obj;
378
379         if (!is_null_sha1(sha1)) {
380                 obj = lookup_object(sha1);
381                 if (obj) {
382                         obj->used = 1;
383                         mark_object_reachable(obj);
384                 } else {
385                         error("%s: invalid reflog entry %s", refname, sha1_to_hex(sha1));
386                         errors_found |= ERROR_REACHABLE;
387                 }
388         }
389 }
390
391 static int fsck_handle_reflog_ent(unsigned char *osha1, unsigned char *nsha1,
392                 const char *email, unsigned long timestamp, int tz,
393                 const char *message, void *cb_data)
394 {
395         const char *refname = cb_data;
396
397         if (verbose)
398                 fprintf(stderr, "Checking reflog %s->%s\n",
399                         sha1_to_hex(osha1), sha1_to_hex(nsha1));
400
401         fsck_handle_reflog_sha1(refname, osha1);
402         fsck_handle_reflog_sha1(refname, nsha1);
403         return 0;
404 }
405
406 static int fsck_handle_reflog(const char *logname, const struct object_id *oid,
407                               int flag, void *cb_data)
408 {
409         for_each_reflog_ent(logname, fsck_handle_reflog_ent, (void *)logname);
410         return 0;
411 }
412
413 static int fsck_handle_ref(const char *refname, const struct object_id *oid,
414                            int flag, void *cb_data)
415 {
416         struct object *obj;
417
418         obj = parse_object(oid->hash);
419         if (!obj) {
420                 error("%s: invalid sha1 pointer %s", refname, oid_to_hex(oid));
421                 errors_found |= ERROR_REACHABLE;
422                 /* We'll continue with the rest despite the error.. */
423                 return 0;
424         }
425         if (obj->type != OBJ_COMMIT && is_branch(refname)) {
426                 error("%s: not a commit", refname);
427                 errors_found |= ERROR_REFS;
428         }
429         default_refs++;
430         obj->used = 1;
431         mark_object_reachable(obj);
432
433         return 0;
434 }
435
436 static void get_default_heads(void)
437 {
438         if (head_points_at && !is_null_oid(&head_oid))
439                 fsck_handle_ref("HEAD", &head_oid, 0, NULL);
440         for_each_rawref(fsck_handle_ref, NULL);
441         if (include_reflogs)
442                 for_each_reflog(fsck_handle_reflog, NULL);
443
444         /*
445          * Not having any default heads isn't really fatal, but
446          * it does mean that "--unreachable" no longer makes any
447          * sense (since in this case everything will obviously
448          * be unreachable by definition.
449          *
450          * Showing dangling objects is valid, though (as those
451          * dangling objects are likely lost heads).
452          *
453          * So we just print a warning about it, and clear the
454          * "show_unreachable" flag.
455          */
456         if (!default_refs) {
457                 fprintf(stderr, "notice: No default references\n");
458                 show_unreachable = 0;
459         }
460 }
461
462 static int fsck_loose(const unsigned char *sha1, const char *path, void *data)
463 {
464         if (fsck_sha1(sha1))
465                 errors_found |= ERROR_OBJECT;
466         return 0;
467 }
468
469 static int fsck_cruft(const char *basename, const char *path, void *data)
470 {
471         if (!starts_with(basename, "tmp_obj_"))
472                 fprintf(stderr, "bad sha1 file: %s\n", path);
473         return 0;
474 }
475
476 static int fsck_subdir(int nr, const char *path, void *progress)
477 {
478         display_progress(progress, nr + 1);
479         return 0;
480 }
481
482 static void fsck_object_dir(const char *path)
483 {
484         struct progress *progress = NULL;
485
486         if (verbose)
487                 fprintf(stderr, "Checking object directory\n");
488
489         if (show_progress)
490                 progress = start_progress(_("Checking object directories"), 256);
491
492         for_each_loose_file_in_objdir(path, fsck_loose, fsck_cruft, fsck_subdir,
493                                       progress);
494         display_progress(progress, 256);
495         stop_progress(&progress);
496 }
497
498 static int fsck_head_link(void)
499 {
500         int null_is_error = 0;
501
502         if (verbose)
503                 fprintf(stderr, "Checking HEAD link\n");
504
505         head_points_at = resolve_ref_unsafe("HEAD", 0, head_oid.hash, NULL);
506         if (!head_points_at) {
507                 errors_found |= ERROR_REFS;
508                 return error("Invalid HEAD");
509         }
510         if (!strcmp(head_points_at, "HEAD"))
511                 /* detached HEAD */
512                 null_is_error = 1;
513         else if (!starts_with(head_points_at, "refs/heads/")) {
514                 errors_found |= ERROR_REFS;
515                 return error("HEAD points to something strange (%s)",
516                              head_points_at);
517         }
518         if (is_null_oid(&head_oid)) {
519                 if (null_is_error) {
520                         errors_found |= ERROR_REFS;
521                         return error("HEAD: detached HEAD points at nothing");
522                 }
523                 fprintf(stderr, "notice: HEAD points to an unborn branch (%s)\n",
524                         head_points_at + 11);
525         }
526         return 0;
527 }
528
529 static int fsck_cache_tree(struct cache_tree *it)
530 {
531         int i;
532         int err = 0;
533
534         if (verbose)
535                 fprintf(stderr, "Checking cache tree\n");
536
537         if (0 <= it->entry_count) {
538                 struct object *obj = parse_object(it->sha1);
539                 if (!obj) {
540                         error("%s: invalid sha1 pointer in cache-tree",
541                               sha1_to_hex(it->sha1));
542                         errors_found |= ERROR_REFS;
543                         return 1;
544                 }
545                 obj->used = 1;
546                 mark_object_reachable(obj);
547                 if (obj->type != OBJ_TREE)
548                         err |= objerror(obj, "non-tree in cache-tree");
549         }
550         for (i = 0; i < it->subtree_nr; i++)
551                 err |= fsck_cache_tree(it->down[i]->cache_tree);
552         return err;
553 }
554
555 static char const * const fsck_usage[] = {
556         N_("git fsck [<options>] [<object>...]"),
557         NULL
558 };
559
560 static struct option fsck_opts[] = {
561         OPT__VERBOSE(&verbose, N_("be verbose")),
562         OPT_BOOL(0, "unreachable", &show_unreachable, N_("show unreachable objects")),
563         OPT_BOOL(0, "dangling", &show_dangling, N_("show dangling objects")),
564         OPT_BOOL(0, "tags", &show_tags, N_("report tags")),
565         OPT_BOOL(0, "root", &show_root, N_("report root nodes")),
566         OPT_BOOL(0, "cache", &keep_cache_objects, N_("make index objects head nodes")),
567         OPT_BOOL(0, "reflogs", &include_reflogs, N_("make reflogs head nodes (default)")),
568         OPT_BOOL(0, "full", &check_full, N_("also consider packs and alternate objects")),
569         OPT_BOOL(0, "connectivity-only", &connectivity_only, N_("check only connectivity")),
570         OPT_BOOL(0, "strict", &check_strict, N_("enable more strict checking")),
571         OPT_BOOL(0, "lost-found", &write_lost_and_found,
572                                 N_("write dangling objects in .git/lost-found")),
573         OPT_BOOL(0, "progress", &show_progress, N_("show progress")),
574         OPT_END(),
575 };
576
577 int cmd_fsck(int argc, const char **argv, const char *prefix)
578 {
579         int i, heads;
580         struct alternate_object_database *alt;
581
582         errors_found = 0;
583         check_replace_refs = 0;
584
585         argc = parse_options(argc, argv, prefix, fsck_opts, fsck_usage, 0);
586
587         fsck_walk_options.walk = mark_object;
588         fsck_obj_options.walk = mark_used;
589         fsck_obj_options.error_func = fsck_error_func;
590         if (check_strict)
591                 fsck_obj_options.strict = 1;
592
593         if (show_progress == -1)
594                 show_progress = isatty(2);
595         if (verbose)
596                 show_progress = 0;
597
598         if (write_lost_and_found) {
599                 check_full = 1;
600                 include_reflogs = 0;
601         }
602
603         git_config(fsck_config, NULL);
604
605         fsck_head_link();
606         if (!connectivity_only) {
607                 fsck_object_dir(get_object_directory());
608
609                 prepare_alt_odb();
610                 for (alt = alt_odb_list; alt; alt = alt->next) {
611                         /* directory name, minus trailing slash */
612                         size_t namelen = alt->name - alt->base - 1;
613                         struct strbuf name = STRBUF_INIT;
614                         strbuf_add(&name, alt->base, namelen);
615                         fsck_object_dir(name.buf);
616                         strbuf_release(&name);
617                 }
618         }
619
620         if (check_full) {
621                 struct packed_git *p;
622                 uint32_t total = 0, count = 0;
623                 struct progress *progress = NULL;
624
625                 prepare_packed_git();
626
627                 if (show_progress) {
628                         for (p = packed_git; p; p = p->next) {
629                                 if (open_pack_index(p))
630                                         continue;
631                                 total += p->num_objects;
632                         }
633
634                         progress = start_progress(_("Checking objects"), total);
635                 }
636                 for (p = packed_git; p; p = p->next) {
637                         /* verify gives error messages itself */
638                         if (verify_pack(p, fsck_obj_buffer,
639                                         progress, count))
640                                 errors_found |= ERROR_PACK;
641                         count += p->num_objects;
642                 }
643                 stop_progress(&progress);
644         }
645
646         heads = 0;
647         for (i = 0; i < argc; i++) {
648                 const char *arg = argv[i];
649                 unsigned char sha1[20];
650                 if (!get_sha1(arg, sha1)) {
651                         struct object *obj = lookup_object(sha1);
652
653                         /* Error is printed by lookup_object(). */
654                         if (!obj)
655                                 continue;
656
657                         obj->used = 1;
658                         mark_object_reachable(obj);
659                         heads++;
660                         continue;
661                 }
662                 error("invalid parameter: expected sha1, got '%s'", arg);
663         }
664
665         /*
666          * If we've not been given any explicit head information, do the
667          * default ones from .git/refs. We also consider the index file
668          * in this case (ie this implies --cache).
669          */
670         if (!heads) {
671                 get_default_heads();
672                 keep_cache_objects = 1;
673         }
674
675         if (keep_cache_objects) {
676                 read_cache();
677                 for (i = 0; i < active_nr; i++) {
678                         unsigned int mode;
679                         struct blob *blob;
680                         struct object *obj;
681
682                         mode = active_cache[i]->ce_mode;
683                         if (S_ISGITLINK(mode))
684                                 continue;
685                         blob = lookup_blob(active_cache[i]->sha1);
686                         if (!blob)
687                                 continue;
688                         obj = &blob->object;
689                         obj->used = 1;
690                         mark_object_reachable(obj);
691                 }
692                 if (active_cache_tree)
693                         fsck_cache_tree(active_cache_tree);
694         }
695
696         check_connectivity();
697         return errors_found;
698 }