Merge branch 'nd/trace-with-env'
[git] / builtin / fsck.c
1 #include "builtin.h"
2 #include "cache.h"
3 #include "config.h"
4 #include "commit.h"
5 #include "tree.h"
6 #include "blob.h"
7 #include "tag.h"
8 #include "refs.h"
9 #include "pack.h"
10 #include "cache-tree.h"
11 #include "tree-walk.h"
12 #include "fsck.h"
13 #include "parse-options.h"
14 #include "dir.h"
15 #include "progress.h"
16 #include "streaming.h"
17 #include "decorate.h"
18 #include "packfile.h"
19
20 #define REACHABLE 0x0001
21 #define SEEN      0x0002
22 #define HAS_OBJ   0x0004
23 /* This flag is set if something points to this object. */
24 #define USED      0x0008
25
26 static int show_root;
27 static int show_tags;
28 static int show_unreachable;
29 static int include_reflogs = 1;
30 static int check_full = 1;
31 static int connectivity_only;
32 static int check_strict;
33 static int keep_cache_objects;
34 static struct fsck_options fsck_walk_options = FSCK_OPTIONS_DEFAULT;
35 static struct fsck_options fsck_obj_options = FSCK_OPTIONS_DEFAULT;
36 static struct object_id head_oid;
37 static const char *head_points_at;
38 static int errors_found;
39 static int write_lost_and_found;
40 static int verbose;
41 static int show_progress = -1;
42 static int show_dangling = 1;
43 static int name_objects;
44 #define ERROR_OBJECT 01
45 #define ERROR_REACHABLE 02
46 #define ERROR_PACK 04
47 #define ERROR_REFS 010
48
49 static const char *describe_object(struct object *obj)
50 {
51         static struct strbuf buf = STRBUF_INIT;
52         char *name = name_objects ?
53                 lookup_decoration(fsck_walk_options.object_names, obj) : NULL;
54
55         strbuf_reset(&buf);
56         strbuf_addstr(&buf, oid_to_hex(&obj->oid));
57         if (name)
58                 strbuf_addf(&buf, " (%s)", name);
59
60         return buf.buf;
61 }
62
63 static const char *printable_type(struct object *obj)
64 {
65         const char *ret;
66
67         if (obj->type == OBJ_NONE) {
68                 enum object_type type = sha1_object_info(obj->oid.hash, NULL);
69                 if (type > 0)
70                         object_as_type(obj, type, 0);
71         }
72
73         ret = typename(obj->type);
74         if (!ret)
75                 ret = "unknown";
76
77         return ret;
78 }
79
80 static int fsck_config(const char *var, const char *value, void *cb)
81 {
82         if (strcmp(var, "fsck.skiplist") == 0) {
83                 const char *path;
84                 struct strbuf sb = STRBUF_INIT;
85
86                 if (git_config_pathname(&path, var, value))
87                         return 1;
88                 strbuf_addf(&sb, "skiplist=%s", path);
89                 free((char *)path);
90                 fsck_set_msg_types(&fsck_obj_options, sb.buf);
91                 strbuf_release(&sb);
92                 return 0;
93         }
94
95         if (skip_prefix(var, "fsck.", &var)) {
96                 fsck_set_msg_type(&fsck_obj_options, var, value);
97                 return 0;
98         }
99
100         return git_default_config(var, value, cb);
101 }
102
103 static void objreport(struct object *obj, const char *msg_type,
104                         const char *err)
105 {
106         fprintf(stderr, "%s in %s %s: %s\n",
107                 msg_type, printable_type(obj), describe_object(obj), err);
108 }
109
110 static int objerror(struct object *obj, const char *err)
111 {
112         errors_found |= ERROR_OBJECT;
113         objreport(obj, "error", err);
114         return -1;
115 }
116
117 static int fsck_error_func(struct fsck_options *o,
118         struct object *obj, int type, const char *message)
119 {
120         objreport(obj, (type == FSCK_WARN) ? "warning" : "error", message);
121         return (type == FSCK_WARN) ? 0 : 1;
122 }
123
124 static struct object_array pending;
125
126 static int mark_object(struct object *obj, int type, void *data, struct fsck_options *options)
127 {
128         struct object *parent = data;
129
130         /*
131          * The only case data is NULL or type is OBJ_ANY is when
132          * mark_object_reachable() calls us.  All the callers of
133          * that function has non-NULL obj hence ...
134          */
135         if (!obj) {
136                 /* ... these references to parent->fld are safe here */
137                 printf("broken link from %7s %s\n",
138                            printable_type(parent), describe_object(parent));
139                 printf("broken link from %7s %s\n",
140                            (type == OBJ_ANY ? "unknown" : typename(type)), "unknown");
141                 errors_found |= ERROR_REACHABLE;
142                 return 1;
143         }
144
145         if (type != OBJ_ANY && obj->type != type)
146                 /* ... and the reference to parent is safe here */
147                 objerror(parent, "wrong object type in link");
148
149         if (obj->flags & REACHABLE)
150                 return 0;
151         obj->flags |= REACHABLE;
152
153         if (is_promisor_object(&obj->oid))
154                 /*
155                  * Further recursion does not need to be performed on this
156                  * object since it is a promisor object (so it does not need to
157                  * be added to "pending").
158                  */
159                 return 0;
160
161         if (!(obj->flags & HAS_OBJ)) {
162                 if (parent && !has_object_file(&obj->oid)) {
163                         printf("broken link from %7s %s\n",
164                                  printable_type(parent), describe_object(parent));
165                         printf("              to %7s %s\n",
166                                  printable_type(obj), describe_object(obj));
167                         errors_found |= ERROR_REACHABLE;
168                 }
169                 return 1;
170         }
171
172         add_object_array(obj, NULL, &pending);
173         return 0;
174 }
175
176 static void mark_object_reachable(struct object *obj)
177 {
178         mark_object(obj, OBJ_ANY, NULL, NULL);
179 }
180
181 static int traverse_one_object(struct object *obj)
182 {
183         return fsck_walk(obj, obj, &fsck_walk_options);
184 }
185
186 static int traverse_reachable(void)
187 {
188         struct progress *progress = NULL;
189         unsigned int nr = 0;
190         int result = 0;
191         if (show_progress)
192                 progress = start_delayed_progress(_("Checking connectivity"), 0);
193         while (pending.nr) {
194                 result |= traverse_one_object(object_array_pop(&pending));
195                 display_progress(progress, ++nr);
196         }
197         stop_progress(&progress);
198         return !!result;
199 }
200
201 static int mark_used(struct object *obj, int type, void *data, struct fsck_options *options)
202 {
203         if (!obj)
204                 return 1;
205         obj->flags |= USED;
206         return 0;
207 }
208
209 /*
210  * Check a single reachable object
211  */
212 static void check_reachable_object(struct object *obj)
213 {
214         /*
215          * We obviously want the object to be parsed,
216          * except if it was in a pack-file and we didn't
217          * do a full fsck
218          */
219         if (!(obj->flags & HAS_OBJ)) {
220                 if (is_promisor_object(&obj->oid))
221                         return;
222                 if (has_sha1_pack(obj->oid.hash))
223                         return; /* it is in pack - forget about it */
224                 printf("missing %s %s\n", printable_type(obj),
225                         describe_object(obj));
226                 errors_found |= ERROR_REACHABLE;
227                 return;
228         }
229 }
230
231 /*
232  * Check a single unreachable object
233  */
234 static void check_unreachable_object(struct object *obj)
235 {
236         /*
237          * Missing unreachable object? Ignore it. It's not like
238          * we miss it (since it can't be reached), nor do we want
239          * to complain about it being unreachable (since it does
240          * not exist).
241          */
242         if (!(obj->flags & HAS_OBJ))
243                 return;
244
245         /*
246          * Unreachable object that exists? Show it if asked to,
247          * since this is something that is prunable.
248          */
249         if (show_unreachable) {
250                 printf("unreachable %s %s\n", printable_type(obj),
251                         describe_object(obj));
252                 return;
253         }
254
255         /*
256          * "!USED" means that nothing at all points to it, including
257          * other unreachable objects. In other words, it's the "tip"
258          * of some set of unreachable objects, usually a commit that
259          * got dropped.
260          *
261          * Such starting points are more interesting than some random
262          * set of unreachable objects, so we show them even if the user
263          * hasn't asked for _all_ unreachable objects. If you have
264          * deleted a branch by mistake, this is a prime candidate to
265          * start looking at, for example.
266          */
267         if (!(obj->flags & USED)) {
268                 if (show_dangling)
269                         printf("dangling %s %s\n", printable_type(obj),
270                                describe_object(obj));
271                 if (write_lost_and_found) {
272                         char *filename = git_pathdup("lost-found/%s/%s",
273                                 obj->type == OBJ_COMMIT ? "commit" : "other",
274                                 describe_object(obj));
275                         FILE *f;
276
277                         if (safe_create_leading_directories_const(filename)) {
278                                 error("Could not create lost-found");
279                                 free(filename);
280                                 return;
281                         }
282                         f = xfopen(filename, "w");
283                         if (obj->type == OBJ_BLOB) {
284                                 if (stream_blob_to_fd(fileno(f), &obj->oid, NULL, 1))
285                                         die_errno("Could not write '%s'", filename);
286                         } else
287                                 fprintf(f, "%s\n", describe_object(obj));
288                         if (fclose(f))
289                                 die_errno("Could not finish '%s'",
290                                           filename);
291                         free(filename);
292                 }
293                 return;
294         }
295
296         /*
297          * Otherwise? It's there, it's unreachable, and some other unreachable
298          * object points to it. Ignore it - it's not interesting, and we showed
299          * all the interesting cases above.
300          */
301 }
302
303 static void check_object(struct object *obj)
304 {
305         if (verbose)
306                 fprintf(stderr, "Checking %s\n", describe_object(obj));
307
308         if (obj->flags & REACHABLE)
309                 check_reachable_object(obj);
310         else
311                 check_unreachable_object(obj);
312 }
313
314 static void check_connectivity(void)
315 {
316         int i, max;
317
318         /* Traverse the pending reachable objects */
319         traverse_reachable();
320
321         /* Look up all the requirements, warn about missing objects.. */
322         max = get_max_object_index();
323         if (verbose)
324                 fprintf(stderr, "Checking connectivity (%d objects)\n", max);
325
326         for (i = 0; i < max; i++) {
327                 struct object *obj = get_indexed_object(i);
328
329                 if (obj)
330                         check_object(obj);
331         }
332 }
333
334 static int fsck_obj(struct object *obj)
335 {
336         int err;
337
338         if (obj->flags & SEEN)
339                 return 0;
340         obj->flags |= SEEN;
341
342         if (verbose)
343                 fprintf(stderr, "Checking %s %s\n",
344                         printable_type(obj), describe_object(obj));
345
346         if (fsck_walk(obj, NULL, &fsck_obj_options))
347                 objerror(obj, "broken links");
348         err = fsck_object(obj, NULL, 0, &fsck_obj_options);
349         if (err)
350                 goto out;
351
352         if (obj->type == OBJ_COMMIT) {
353                 struct commit *commit = (struct commit *) obj;
354
355                 if (!commit->parents && show_root)
356                         printf("root %s\n", describe_object(&commit->object));
357         }
358
359         if (obj->type == OBJ_TAG) {
360                 struct tag *tag = (struct tag *) obj;
361
362                 if (show_tags && tag->tagged) {
363                         printf("tagged %s %s", printable_type(tag->tagged),
364                                 describe_object(tag->tagged));
365                         printf(" (%s) in %s\n", tag->tag,
366                                 describe_object(&tag->object));
367                 }
368         }
369
370 out:
371         if (obj->type == OBJ_TREE)
372                 free_tree_buffer((struct tree *)obj);
373         if (obj->type == OBJ_COMMIT)
374                 free_commit_buffer((struct commit *)obj);
375         return err;
376 }
377
378 static int fsck_obj_buffer(const struct object_id *oid, enum object_type type,
379                            unsigned long size, void *buffer, int *eaten)
380 {
381         /*
382          * Note, buffer may be NULL if type is OBJ_BLOB. See
383          * verify_packfile(), data_valid variable for details.
384          */
385         struct object *obj;
386         obj = parse_object_buffer(oid, type, size, buffer, eaten);
387         if (!obj) {
388                 errors_found |= ERROR_OBJECT;
389                 return error("%s: object corrupt or missing", oid_to_hex(oid));
390         }
391         obj->flags &= ~(REACHABLE | SEEN);
392         obj->flags |= HAS_OBJ;
393         return fsck_obj(obj);
394 }
395
396 static int default_refs;
397
398 static void fsck_handle_reflog_oid(const char *refname, struct object_id *oid,
399         timestamp_t timestamp)
400 {
401         struct object *obj;
402
403         if (!is_null_oid(oid)) {
404                 obj = lookup_object(oid->hash);
405                 if (obj && (obj->flags & HAS_OBJ)) {
406                         if (timestamp && name_objects)
407                                 add_decoration(fsck_walk_options.object_names,
408                                         obj,
409                                         xstrfmt("%s@{%"PRItime"}", refname, timestamp));
410                         obj->flags |= USED;
411                         mark_object_reachable(obj);
412                 } else if (!is_promisor_object(oid)) {
413                         error("%s: invalid reflog entry %s", refname, oid_to_hex(oid));
414                         errors_found |= ERROR_REACHABLE;
415                 }
416         }
417 }
418
419 static int fsck_handle_reflog_ent(struct object_id *ooid, struct object_id *noid,
420                 const char *email, timestamp_t timestamp, int tz,
421                 const char *message, void *cb_data)
422 {
423         const char *refname = cb_data;
424
425         if (verbose)
426                 fprintf(stderr, "Checking reflog %s->%s\n",
427                         oid_to_hex(ooid), oid_to_hex(noid));
428
429         fsck_handle_reflog_oid(refname, ooid, 0);
430         fsck_handle_reflog_oid(refname, noid, timestamp);
431         return 0;
432 }
433
434 static int fsck_handle_reflog(const char *logname, const struct object_id *oid,
435                               int flag, void *cb_data)
436 {
437         for_each_reflog_ent(logname, fsck_handle_reflog_ent, (void *)logname);
438         return 0;
439 }
440
441 static int fsck_handle_ref(const char *refname, const struct object_id *oid,
442                            int flag, void *cb_data)
443 {
444         struct object *obj;
445
446         obj = parse_object(oid);
447         if (!obj) {
448                 if (is_promisor_object(oid)) {
449                         /*
450                          * Increment default_refs anyway, because this is a
451                          * valid ref.
452                          */
453                          default_refs++;
454                          return 0;
455                 }
456                 error("%s: invalid sha1 pointer %s", refname, oid_to_hex(oid));
457                 errors_found |= ERROR_REACHABLE;
458                 /* We'll continue with the rest despite the error.. */
459                 return 0;
460         }
461         if (obj->type != OBJ_COMMIT && is_branch(refname)) {
462                 error("%s: not a commit", refname);
463                 errors_found |= ERROR_REFS;
464         }
465         default_refs++;
466         obj->flags |= USED;
467         if (name_objects)
468                 add_decoration(fsck_walk_options.object_names,
469                         obj, xstrdup(refname));
470         mark_object_reachable(obj);
471
472         return 0;
473 }
474
475 static void get_default_heads(void)
476 {
477         if (head_points_at && !is_null_oid(&head_oid))
478                 fsck_handle_ref("HEAD", &head_oid, 0, NULL);
479         for_each_rawref(fsck_handle_ref, NULL);
480         if (include_reflogs)
481                 for_each_reflog(fsck_handle_reflog, NULL);
482
483         /*
484          * Not having any default heads isn't really fatal, but
485          * it does mean that "--unreachable" no longer makes any
486          * sense (since in this case everything will obviously
487          * be unreachable by definition.
488          *
489          * Showing dangling objects is valid, though (as those
490          * dangling objects are likely lost heads).
491          *
492          * So we just print a warning about it, and clear the
493          * "show_unreachable" flag.
494          */
495         if (!default_refs) {
496                 fprintf(stderr, "notice: No default references\n");
497                 show_unreachable = 0;
498         }
499 }
500
501 static struct object *parse_loose_object(const struct object_id *oid,
502                                          const char *path)
503 {
504         struct object *obj;
505         void *contents;
506         enum object_type type;
507         unsigned long size;
508         int eaten;
509
510         if (read_loose_object(path, oid->hash, &type, &size, &contents) < 0)
511                 return NULL;
512
513         if (!contents && type != OBJ_BLOB)
514                 die("BUG: read_loose_object streamed a non-blob");
515
516         obj = parse_object_buffer(oid, type, size, contents, &eaten);
517
518         if (!eaten)
519                 free(contents);
520         return obj;
521 }
522
523 static int fsck_loose(const struct object_id *oid, const char *path, void *data)
524 {
525         struct object *obj = parse_loose_object(oid, path);
526
527         if (!obj) {
528                 errors_found |= ERROR_OBJECT;
529                 error("%s: object corrupt or missing: %s",
530                       oid_to_hex(oid), path);
531                 return 0; /* keep checking other objects */
532         }
533
534         obj->flags &= ~(REACHABLE | SEEN);
535         obj->flags |= HAS_OBJ;
536         if (fsck_obj(obj))
537                 errors_found |= ERROR_OBJECT;
538         return 0;
539 }
540
541 static int fsck_cruft(const char *basename, const char *path, void *data)
542 {
543         if (!starts_with(basename, "tmp_obj_"))
544                 fprintf(stderr, "bad sha1 file: %s\n", path);
545         return 0;
546 }
547
548 static int fsck_subdir(unsigned int nr, const char *path, void *progress)
549 {
550         display_progress(progress, nr + 1);
551         return 0;
552 }
553
554 static void fsck_object_dir(const char *path)
555 {
556         struct progress *progress = NULL;
557
558         if (verbose)
559                 fprintf(stderr, "Checking object directory\n");
560
561         if (show_progress)
562                 progress = start_progress(_("Checking object directories"), 256);
563
564         for_each_loose_file_in_objdir(path, fsck_loose, fsck_cruft, fsck_subdir,
565                                       progress);
566         display_progress(progress, 256);
567         stop_progress(&progress);
568 }
569
570 static int fsck_head_link(void)
571 {
572         int null_is_error = 0;
573
574         if (verbose)
575                 fprintf(stderr, "Checking HEAD link\n");
576
577         head_points_at = resolve_ref_unsafe("HEAD", 0, &head_oid, NULL);
578         if (!head_points_at) {
579                 errors_found |= ERROR_REFS;
580                 return error("Invalid HEAD");
581         }
582         if (!strcmp(head_points_at, "HEAD"))
583                 /* detached HEAD */
584                 null_is_error = 1;
585         else if (!starts_with(head_points_at, "refs/heads/")) {
586                 errors_found |= ERROR_REFS;
587                 return error("HEAD points to something strange (%s)",
588                              head_points_at);
589         }
590         if (is_null_oid(&head_oid)) {
591                 if (null_is_error) {
592                         errors_found |= ERROR_REFS;
593                         return error("HEAD: detached HEAD points at nothing");
594                 }
595                 fprintf(stderr, "notice: HEAD points to an unborn branch (%s)\n",
596                         head_points_at + 11);
597         }
598         return 0;
599 }
600
601 static int fsck_cache_tree(struct cache_tree *it)
602 {
603         int i;
604         int err = 0;
605
606         if (verbose)
607                 fprintf(stderr, "Checking cache tree\n");
608
609         if (0 <= it->entry_count) {
610                 struct object *obj = parse_object(&it->oid);
611                 if (!obj) {
612                         error("%s: invalid sha1 pointer in cache-tree",
613                               oid_to_hex(&it->oid));
614                         errors_found |= ERROR_REFS;
615                         return 1;
616                 }
617                 obj->flags |= USED;
618                 if (name_objects)
619                         add_decoration(fsck_walk_options.object_names,
620                                 obj, xstrdup(":"));
621                 mark_object_reachable(obj);
622                 if (obj->type != OBJ_TREE)
623                         err |= objerror(obj, "non-tree in cache-tree");
624         }
625         for (i = 0; i < it->subtree_nr; i++)
626                 err |= fsck_cache_tree(it->down[i]->cache_tree);
627         return err;
628 }
629
630 static void mark_object_for_connectivity(const struct object_id *oid)
631 {
632         struct object *obj = lookup_unknown_object(oid->hash);
633         obj->flags |= HAS_OBJ;
634 }
635
636 static int mark_loose_for_connectivity(const struct object_id *oid,
637                                        const char *path,
638                                        void *data)
639 {
640         mark_object_for_connectivity(oid);
641         return 0;
642 }
643
644 static int mark_packed_for_connectivity(const struct object_id *oid,
645                                         struct packed_git *pack,
646                                         uint32_t pos,
647                                         void *data)
648 {
649         mark_object_for_connectivity(oid);
650         return 0;
651 }
652
653 static char const * const fsck_usage[] = {
654         N_("git fsck [<options>] [<object>...]"),
655         NULL
656 };
657
658 static struct option fsck_opts[] = {
659         OPT__VERBOSE(&verbose, N_("be verbose")),
660         OPT_BOOL(0, "unreachable", &show_unreachable, N_("show unreachable objects")),
661         OPT_BOOL(0, "dangling", &show_dangling, N_("show dangling objects")),
662         OPT_BOOL(0, "tags", &show_tags, N_("report tags")),
663         OPT_BOOL(0, "root", &show_root, N_("report root nodes")),
664         OPT_BOOL(0, "cache", &keep_cache_objects, N_("make index objects head nodes")),
665         OPT_BOOL(0, "reflogs", &include_reflogs, N_("make reflogs head nodes (default)")),
666         OPT_BOOL(0, "full", &check_full, N_("also consider packs and alternate objects")),
667         OPT_BOOL(0, "connectivity-only", &connectivity_only, N_("check only connectivity")),
668         OPT_BOOL(0, "strict", &check_strict, N_("enable more strict checking")),
669         OPT_BOOL(0, "lost-found", &write_lost_and_found,
670                                 N_("write dangling objects in .git/lost-found")),
671         OPT_BOOL(0, "progress", &show_progress, N_("show progress")),
672         OPT_BOOL(0, "name-objects", &name_objects, N_("show verbose names for reachable objects")),
673         OPT_END(),
674 };
675
676 int cmd_fsck(int argc, const char **argv, const char *prefix)
677 {
678         int i;
679         struct alternate_object_database *alt;
680
681         /* fsck knows how to handle missing promisor objects */
682         fetch_if_missing = 0;
683
684         errors_found = 0;
685         check_replace_refs = 0;
686
687         argc = parse_options(argc, argv, prefix, fsck_opts, fsck_usage, 0);
688
689         fsck_walk_options.walk = mark_object;
690         fsck_obj_options.walk = mark_used;
691         fsck_obj_options.error_func = fsck_error_func;
692         if (check_strict)
693                 fsck_obj_options.strict = 1;
694
695         if (show_progress == -1)
696                 show_progress = isatty(2);
697         if (verbose)
698                 show_progress = 0;
699
700         if (write_lost_and_found) {
701                 check_full = 1;
702                 include_reflogs = 0;
703         }
704
705         if (name_objects)
706                 fsck_walk_options.object_names =
707                         xcalloc(1, sizeof(struct decoration));
708
709         git_config(fsck_config, NULL);
710
711         fsck_head_link();
712         if (connectivity_only) {
713                 for_each_loose_object(mark_loose_for_connectivity, NULL, 0);
714                 for_each_packed_object(mark_packed_for_connectivity, NULL, 0);
715         } else {
716                 fsck_object_dir(get_object_directory());
717
718                 prepare_alt_odb();
719                 for (alt = alt_odb_list; alt; alt = alt->next)
720                         fsck_object_dir(alt->path);
721
722                 if (check_full) {
723                         struct packed_git *p;
724                         uint32_t total = 0, count = 0;
725                         struct progress *progress = NULL;
726
727                         prepare_packed_git();
728
729                         if (show_progress) {
730                                 for (p = packed_git; p; p = p->next) {
731                                         if (open_pack_index(p))
732                                                 continue;
733                                         total += p->num_objects;
734                                 }
735
736                                 progress = start_progress(_("Checking objects"), total);
737                         }
738                         for (p = packed_git; p; p = p->next) {
739                                 /* verify gives error messages itself */
740                                 if (verify_pack(p, fsck_obj_buffer,
741                                                 progress, count))
742                                         errors_found |= ERROR_PACK;
743                                 count += p->num_objects;
744                         }
745                         stop_progress(&progress);
746                 }
747         }
748
749         for (i = 0; i < argc; i++) {
750                 const char *arg = argv[i];
751                 struct object_id oid;
752                 if (!get_oid(arg, &oid)) {
753                         struct object *obj = lookup_object(oid.hash);
754
755                         if (!obj || !(obj->flags & HAS_OBJ)) {
756                                 if (is_promisor_object(&oid))
757                                         continue;
758                                 error("%s: object missing", oid_to_hex(&oid));
759                                 errors_found |= ERROR_OBJECT;
760                                 continue;
761                         }
762
763                         obj->flags |= USED;
764                         if (name_objects)
765                                 add_decoration(fsck_walk_options.object_names,
766                                         obj, xstrdup(arg));
767                         mark_object_reachable(obj);
768                         continue;
769                 }
770                 error("invalid parameter: expected sha1, got '%s'", arg);
771                 errors_found |= ERROR_OBJECT;
772         }
773
774         /*
775          * If we've not been given any explicit head information, do the
776          * default ones from .git/refs. We also consider the index file
777          * in this case (ie this implies --cache).
778          */
779         if (!argc) {
780                 get_default_heads();
781                 keep_cache_objects = 1;
782         }
783
784         if (keep_cache_objects) {
785                 verify_index_checksum = 1;
786                 verify_ce_order = 1;
787                 read_cache();
788                 for (i = 0; i < active_nr; i++) {
789                         unsigned int mode;
790                         struct blob *blob;
791                         struct object *obj;
792
793                         mode = active_cache[i]->ce_mode;
794                         if (S_ISGITLINK(mode))
795                                 continue;
796                         blob = lookup_blob(&active_cache[i]->oid);
797                         if (!blob)
798                                 continue;
799                         obj = &blob->object;
800                         obj->flags |= USED;
801                         if (name_objects)
802                                 add_decoration(fsck_walk_options.object_names,
803                                         obj,
804                                         xstrfmt(":%s", active_cache[i]->name));
805                         mark_object_reachable(obj);
806                 }
807                 if (active_cache_tree)
808                         fsck_cache_tree(active_cache_tree);
809         }
810
811         check_connectivity();
812         return errors_found;
813 }