Merge branch 'mm/push-social-engineering-attack-doc'
[git] / fsck.c
1 #include "cache.h"
2 #include "object.h"
3 #include "blob.h"
4 #include "tree.h"
5 #include "tree-walk.h"
6 #include "commit.h"
7 #include "tag.h"
8 #include "fsck.h"
9 #include "refs.h"
10 #include "utf8.h"
11 #include "sha1-array.h"
12 #include "decorate.h"
13
14 #define FSCK_FATAL -1
15 #define FSCK_INFO -2
16
17 #define FOREACH_MSG_ID(FUNC) \
18         /* fatal errors */ \
19         FUNC(NUL_IN_HEADER, FATAL) \
20         FUNC(UNTERMINATED_HEADER, FATAL) \
21         /* errors */ \
22         FUNC(BAD_DATE, ERROR) \
23         FUNC(BAD_DATE_OVERFLOW, ERROR) \
24         FUNC(BAD_EMAIL, ERROR) \
25         FUNC(BAD_NAME, ERROR) \
26         FUNC(BAD_OBJECT_SHA1, ERROR) \
27         FUNC(BAD_PARENT_SHA1, ERROR) \
28         FUNC(BAD_TAG_OBJECT, ERROR) \
29         FUNC(BAD_TIMEZONE, ERROR) \
30         FUNC(BAD_TREE, ERROR) \
31         FUNC(BAD_TREE_SHA1, ERROR) \
32         FUNC(BAD_TYPE, ERROR) \
33         FUNC(DUPLICATE_ENTRIES, ERROR) \
34         FUNC(MISSING_AUTHOR, ERROR) \
35         FUNC(MISSING_COMMITTER, ERROR) \
36         FUNC(MISSING_EMAIL, ERROR) \
37         FUNC(MISSING_GRAFT, ERROR) \
38         FUNC(MISSING_NAME_BEFORE_EMAIL, ERROR) \
39         FUNC(MISSING_OBJECT, ERROR) \
40         FUNC(MISSING_PARENT, ERROR) \
41         FUNC(MISSING_SPACE_BEFORE_DATE, ERROR) \
42         FUNC(MISSING_SPACE_BEFORE_EMAIL, ERROR) \
43         FUNC(MISSING_TAG, ERROR) \
44         FUNC(MISSING_TAG_ENTRY, ERROR) \
45         FUNC(MISSING_TAG_OBJECT, ERROR) \
46         FUNC(MISSING_TREE, ERROR) \
47         FUNC(MISSING_TYPE, ERROR) \
48         FUNC(MISSING_TYPE_ENTRY, ERROR) \
49         FUNC(MULTIPLE_AUTHORS, ERROR) \
50         FUNC(TAG_OBJECT_NOT_TAG, ERROR) \
51         FUNC(TREE_NOT_SORTED, ERROR) \
52         FUNC(UNKNOWN_TYPE, ERROR) \
53         FUNC(ZERO_PADDED_DATE, ERROR) \
54         /* warnings */ \
55         FUNC(BAD_FILEMODE, WARN) \
56         FUNC(EMPTY_NAME, WARN) \
57         FUNC(FULL_PATHNAME, WARN) \
58         FUNC(HAS_DOT, WARN) \
59         FUNC(HAS_DOTDOT, WARN) \
60         FUNC(HAS_DOTGIT, WARN) \
61         FUNC(NULL_SHA1, WARN) \
62         FUNC(ZERO_PADDED_FILEMODE, WARN) \
63         FUNC(NUL_IN_COMMIT, WARN) \
64         /* infos (reported as warnings, but ignored by default) */ \
65         FUNC(BAD_TAG_NAME, INFO) \
66         FUNC(MISSING_TAGGER_ENTRY, INFO)
67
68 #define MSG_ID(id, msg_type) FSCK_MSG_##id,
69 enum fsck_msg_id {
70         FOREACH_MSG_ID(MSG_ID)
71         FSCK_MSG_MAX
72 };
73 #undef MSG_ID
74
75 #define STR(x) #x
76 #define MSG_ID(id, msg_type) { STR(id), NULL, FSCK_##msg_type },
77 static struct {
78         const char *id_string;
79         const char *downcased;
80         int msg_type;
81 } msg_id_info[FSCK_MSG_MAX + 1] = {
82         FOREACH_MSG_ID(MSG_ID)
83         { NULL, NULL, -1 }
84 };
85 #undef MSG_ID
86
87 static int parse_msg_id(const char *text)
88 {
89         int i;
90
91         if (!msg_id_info[0].downcased) {
92                 /* convert id_string to lower case, without underscores. */
93                 for (i = 0; i < FSCK_MSG_MAX; i++) {
94                         const char *p = msg_id_info[i].id_string;
95                         int len = strlen(p);
96                         char *q = xmalloc(len);
97
98                         msg_id_info[i].downcased = q;
99                         while (*p)
100                                 if (*p == '_')
101                                         p++;
102                                 else
103                                         *(q)++ = tolower(*(p)++);
104                         *q = '\0';
105                 }
106         }
107
108         for (i = 0; i < FSCK_MSG_MAX; i++)
109                 if (!strcmp(text, msg_id_info[i].downcased))
110                         return i;
111
112         return -1;
113 }
114
115 static int fsck_msg_type(enum fsck_msg_id msg_id,
116         struct fsck_options *options)
117 {
118         int msg_type;
119
120         assert(msg_id >= 0 && msg_id < FSCK_MSG_MAX);
121
122         if (options->msg_type)
123                 msg_type = options->msg_type[msg_id];
124         else {
125                 msg_type = msg_id_info[msg_id].msg_type;
126                 if (options->strict && msg_type == FSCK_WARN)
127                         msg_type = FSCK_ERROR;
128         }
129
130         return msg_type;
131 }
132
133 static void init_skiplist(struct fsck_options *options, const char *path)
134 {
135         static struct sha1_array skiplist = SHA1_ARRAY_INIT;
136         int sorted, fd;
137         char buffer[41];
138         unsigned char sha1[20];
139
140         if (options->skiplist)
141                 sorted = options->skiplist->sorted;
142         else {
143                 sorted = 1;
144                 options->skiplist = &skiplist;
145         }
146
147         fd = open(path, O_RDONLY);
148         if (fd < 0)
149                 die("Could not open skip list: %s", path);
150         for (;;) {
151                 int result = read_in_full(fd, buffer, sizeof(buffer));
152                 if (result < 0)
153                         die_errno("Could not read '%s'", path);
154                 if (!result)
155                         break;
156                 if (get_sha1_hex(buffer, sha1) || buffer[40] != '\n')
157                         die("Invalid SHA-1: %s", buffer);
158                 sha1_array_append(&skiplist, sha1);
159                 if (sorted && skiplist.nr > 1 &&
160                                 hashcmp(skiplist.sha1[skiplist.nr - 2],
161                                         sha1) > 0)
162                         sorted = 0;
163         }
164         close(fd);
165
166         if (sorted)
167                 skiplist.sorted = 1;
168 }
169
170 static int parse_msg_type(const char *str)
171 {
172         if (!strcmp(str, "error"))
173                 return FSCK_ERROR;
174         else if (!strcmp(str, "warn"))
175                 return FSCK_WARN;
176         else if (!strcmp(str, "ignore"))
177                 return FSCK_IGNORE;
178         else
179                 die("Unknown fsck message type: '%s'", str);
180 }
181
182 int is_valid_msg_type(const char *msg_id, const char *msg_type)
183 {
184         if (parse_msg_id(msg_id) < 0)
185                 return 0;
186         parse_msg_type(msg_type);
187         return 1;
188 }
189
190 void fsck_set_msg_type(struct fsck_options *options,
191                 const char *msg_id, const char *msg_type)
192 {
193         int id = parse_msg_id(msg_id), type;
194
195         if (id < 0)
196                 die("Unhandled message id: %s", msg_id);
197         type = parse_msg_type(msg_type);
198
199         if (type != FSCK_ERROR && msg_id_info[id].msg_type == FSCK_FATAL)
200                 die("Cannot demote %s to %s", msg_id, msg_type);
201
202         if (!options->msg_type) {
203                 int i;
204                 int *msg_type;
205                 ALLOC_ARRAY(msg_type, FSCK_MSG_MAX);
206                 for (i = 0; i < FSCK_MSG_MAX; i++)
207                         msg_type[i] = fsck_msg_type(i, options);
208                 options->msg_type = msg_type;
209         }
210
211         options->msg_type[id] = type;
212 }
213
214 void fsck_set_msg_types(struct fsck_options *options, const char *values)
215 {
216         char *buf = xstrdup(values), *to_free = buf;
217         int done = 0;
218
219         while (!done) {
220                 int len = strcspn(buf, " ,|"), equal;
221
222                 done = !buf[len];
223                 if (!len) {
224                         buf++;
225                         continue;
226                 }
227                 buf[len] = '\0';
228
229                 for (equal = 0;
230                      equal < len && buf[equal] != '=' && buf[equal] != ':';
231                      equal++)
232                         buf[equal] = tolower(buf[equal]);
233                 buf[equal] = '\0';
234
235                 if (!strcmp(buf, "skiplist")) {
236                         if (equal == len)
237                                 die("skiplist requires a path");
238                         init_skiplist(options, buf + equal + 1);
239                         buf += len + 1;
240                         continue;
241                 }
242
243                 if (equal == len)
244                         die("Missing '=': '%s'", buf);
245
246                 fsck_set_msg_type(options, buf, buf + equal + 1);
247                 buf += len + 1;
248         }
249         free(to_free);
250 }
251
252 static void append_msg_id(struct strbuf *sb, const char *msg_id)
253 {
254         for (;;) {
255                 char c = *(msg_id)++;
256
257                 if (!c)
258                         break;
259                 if (c != '_')
260                         strbuf_addch(sb, tolower(c));
261                 else {
262                         assert(*msg_id);
263                         strbuf_addch(sb, *(msg_id)++);
264                 }
265         }
266
267         strbuf_addstr(sb, ": ");
268 }
269
270 __attribute__((format (printf, 4, 5)))
271 static int report(struct fsck_options *options, struct object *object,
272         enum fsck_msg_id id, const char *fmt, ...)
273 {
274         va_list ap;
275         struct strbuf sb = STRBUF_INIT;
276         int msg_type = fsck_msg_type(id, options), result;
277
278         if (msg_type == FSCK_IGNORE)
279                 return 0;
280
281         if (options->skiplist && object &&
282                         sha1_array_lookup(options->skiplist, object->oid.hash) >= 0)
283                 return 0;
284
285         if (msg_type == FSCK_FATAL)
286                 msg_type = FSCK_ERROR;
287         else if (msg_type == FSCK_INFO)
288                 msg_type = FSCK_WARN;
289
290         append_msg_id(&sb, msg_id_info[id].id_string);
291
292         va_start(ap, fmt);
293         strbuf_vaddf(&sb, fmt, ap);
294         result = options->error_func(options, object, msg_type, sb.buf);
295         strbuf_release(&sb);
296         va_end(ap);
297
298         return result;
299 }
300
301 static char *get_object_name(struct fsck_options *options, struct object *obj)
302 {
303         if (!options->object_names)
304                 return NULL;
305         return lookup_decoration(options->object_names, obj);
306 }
307
308 static void put_object_name(struct fsck_options *options, struct object *obj,
309         const char *fmt, ...)
310 {
311         va_list ap;
312         struct strbuf buf = STRBUF_INIT;
313         char *existing;
314
315         if (!options->object_names)
316                 return;
317         existing = lookup_decoration(options->object_names, obj);
318         if (existing)
319                 return;
320         va_start(ap, fmt);
321         strbuf_vaddf(&buf, fmt, ap);
322         add_decoration(options->object_names, obj, strbuf_detach(&buf, NULL));
323         va_end(ap);
324 }
325
326 static const char *describe_object(struct fsck_options *o, struct object *obj)
327 {
328         static struct strbuf buf = STRBUF_INIT;
329         char *name;
330
331         strbuf_reset(&buf);
332         strbuf_addstr(&buf, oid_to_hex(&obj->oid));
333         if (o->object_names && (name = lookup_decoration(o->object_names, obj)))
334                 strbuf_addf(&buf, " (%s)", name);
335
336         return buf.buf;
337 }
338
339 static int fsck_walk_tree(struct tree *tree, void *data, struct fsck_options *options)
340 {
341         struct tree_desc desc;
342         struct name_entry entry;
343         int res = 0;
344         const char *name;
345
346         if (parse_tree(tree))
347                 return -1;
348
349         name = get_object_name(options, &tree->object);
350         if (init_tree_desc_gently(&desc, tree->buffer, tree->size))
351                 return -1;
352         while (tree_entry_gently(&desc, &entry)) {
353                 struct object *obj;
354                 int result;
355
356                 if (S_ISGITLINK(entry.mode))
357                         continue;
358
359                 if (S_ISDIR(entry.mode)) {
360                         obj = &lookup_tree(entry.oid->hash)->object;
361                         if (name)
362                                 put_object_name(options, obj, "%s%s/", name,
363                                         entry.path);
364                         result = options->walk(obj, OBJ_TREE, data, options);
365                 }
366                 else if (S_ISREG(entry.mode) || S_ISLNK(entry.mode)) {
367                         obj = &lookup_blob(entry.oid->hash)->object;
368                         if (name)
369                                 put_object_name(options, obj, "%s%s", name,
370                                         entry.path);
371                         result = options->walk(obj, OBJ_BLOB, data, options);
372                 }
373                 else {
374                         result = error("in tree %s: entry %s has bad mode %.6o",
375                                         describe_object(options, &tree->object), entry.path, entry.mode);
376                 }
377                 if (result < 0)
378                         return result;
379                 if (!res)
380                         res = result;
381         }
382         return res;
383 }
384
385 static int fsck_walk_commit(struct commit *commit, void *data, struct fsck_options *options)
386 {
387         int counter = 0, generation = 0, name_prefix_len = 0;
388         struct commit_list *parents;
389         int res;
390         int result;
391         const char *name;
392
393         if (parse_commit(commit))
394                 return -1;
395
396         name = get_object_name(options, &commit->object);
397         if (name)
398                 put_object_name(options, &commit->tree->object, "%s:", name);
399
400         result = options->walk((struct object *)commit->tree, OBJ_TREE, data, options);
401         if (result < 0)
402                 return result;
403         res = result;
404
405         parents = commit->parents;
406         if (name && parents) {
407                 int len = strlen(name), power;
408
409                 if (len && name[len - 1] == '^') {
410                         generation = 1;
411                         name_prefix_len = len - 1;
412                 }
413                 else { /* parse ~<generation> suffix */
414                         for (generation = 0, power = 1;
415                              len && isdigit(name[len - 1]);
416                              power *= 10)
417                                 generation += power * (name[--len] - '0');
418                         if (power > 1 && len && name[len - 1] == '~')
419                                 name_prefix_len = len - 1;
420                 }
421         }
422
423         while (parents) {
424                 if (name) {
425                         struct object *obj = &parents->item->object;
426
427                         if (++counter > 1)
428                                 put_object_name(options, obj, "%s^%d",
429                                         name, counter);
430                         else if (generation > 0)
431                                 put_object_name(options, obj, "%.*s~%d",
432                                         name_prefix_len, name, generation + 1);
433                         else
434                                 put_object_name(options, obj, "%s^", name);
435                 }
436                 result = options->walk((struct object *)parents->item, OBJ_COMMIT, data, options);
437                 if (result < 0)
438                         return result;
439                 if (!res)
440                         res = result;
441                 parents = parents->next;
442         }
443         return res;
444 }
445
446 static int fsck_walk_tag(struct tag *tag, void *data, struct fsck_options *options)
447 {
448         char *name = get_object_name(options, &tag->object);
449
450         if (parse_tag(tag))
451                 return -1;
452         if (name)
453                 put_object_name(options, tag->tagged, "%s", name);
454         return options->walk(tag->tagged, OBJ_ANY, data, options);
455 }
456
457 int fsck_walk(struct object *obj, void *data, struct fsck_options *options)
458 {
459         if (!obj)
460                 return -1;
461         switch (obj->type) {
462         case OBJ_BLOB:
463                 return 0;
464         case OBJ_TREE:
465                 return fsck_walk_tree((struct tree *)obj, data, options);
466         case OBJ_COMMIT:
467                 return fsck_walk_commit((struct commit *)obj, data, options);
468         case OBJ_TAG:
469                 return fsck_walk_tag((struct tag *)obj, data, options);
470         default:
471                 error("Unknown object type for %s", describe_object(options, obj));
472                 return -1;
473         }
474 }
475
476 /*
477  * The entries in a tree are ordered in the _path_ order,
478  * which means that a directory entry is ordered by adding
479  * a slash to the end of it.
480  *
481  * So a directory called "a" is ordered _after_ a file
482  * called "a.c", because "a/" sorts after "a.c".
483  */
484 #define TREE_UNORDERED (-1)
485 #define TREE_HAS_DUPS  (-2)
486
487 static int verify_ordered(unsigned mode1, const char *name1, unsigned mode2, const char *name2)
488 {
489         int len1 = strlen(name1);
490         int len2 = strlen(name2);
491         int len = len1 < len2 ? len1 : len2;
492         unsigned char c1, c2;
493         int cmp;
494
495         cmp = memcmp(name1, name2, len);
496         if (cmp < 0)
497                 return 0;
498         if (cmp > 0)
499                 return TREE_UNORDERED;
500
501         /*
502          * Ok, the first <len> characters are the same.
503          * Now we need to order the next one, but turn
504          * a '\0' into a '/' for a directory entry.
505          */
506         c1 = name1[len];
507         c2 = name2[len];
508         if (!c1 && !c2)
509                 /*
510                  * git-write-tree used to write out a nonsense tree that has
511                  * entries with the same name, one blob and one tree.  Make
512                  * sure we do not have duplicate entries.
513                  */
514                 return TREE_HAS_DUPS;
515         if (!c1 && S_ISDIR(mode1))
516                 c1 = '/';
517         if (!c2 && S_ISDIR(mode2))
518                 c2 = '/';
519         return c1 < c2 ? 0 : TREE_UNORDERED;
520 }
521
522 static int fsck_tree(struct tree *item, struct fsck_options *options)
523 {
524         int retval = 0;
525         int has_null_sha1 = 0;
526         int has_full_path = 0;
527         int has_empty_name = 0;
528         int has_dot = 0;
529         int has_dotdot = 0;
530         int has_dotgit = 0;
531         int has_zero_pad = 0;
532         int has_bad_modes = 0;
533         int has_dup_entries = 0;
534         int not_properly_sorted = 0;
535         struct tree_desc desc;
536         unsigned o_mode;
537         const char *o_name;
538
539         if (init_tree_desc_gently(&desc, item->buffer, item->size)) {
540                 retval += report(options, &item->object, FSCK_MSG_BAD_TREE, "cannot be parsed as a tree");
541                 return retval;
542         }
543
544         o_mode = 0;
545         o_name = NULL;
546
547         while (desc.size) {
548                 unsigned mode;
549                 const char *name;
550                 const struct object_id *oid;
551
552                 oid = tree_entry_extract(&desc, &name, &mode);
553
554                 has_null_sha1 |= is_null_oid(oid);
555                 has_full_path |= !!strchr(name, '/');
556                 has_empty_name |= !*name;
557                 has_dot |= !strcmp(name, ".");
558                 has_dotdot |= !strcmp(name, "..");
559                 has_dotgit |= (!strcmp(name, ".git") ||
560                                is_hfs_dotgit(name) ||
561                                is_ntfs_dotgit(name));
562                 has_zero_pad |= *(char *)desc.buffer == '0';
563                 if (update_tree_entry_gently(&desc)) {
564                         retval += report(options, &item->object, FSCK_MSG_BAD_TREE, "cannot be parsed as a tree");
565                         break;
566                 }
567
568                 switch (mode) {
569                 /*
570                  * Standard modes..
571                  */
572                 case S_IFREG | 0755:
573                 case S_IFREG | 0644:
574                 case S_IFLNK:
575                 case S_IFDIR:
576                 case S_IFGITLINK:
577                         break;
578                 /*
579                  * This is nonstandard, but we had a few of these
580                  * early on when we honored the full set of mode
581                  * bits..
582                  */
583                 case S_IFREG | 0664:
584                         if (!options->strict)
585                                 break;
586                 default:
587                         has_bad_modes = 1;
588                 }
589
590                 if (o_name) {
591                         switch (verify_ordered(o_mode, o_name, mode, name)) {
592                         case TREE_UNORDERED:
593                                 not_properly_sorted = 1;
594                                 break;
595                         case TREE_HAS_DUPS:
596                                 has_dup_entries = 1;
597                                 break;
598                         default:
599                                 break;
600                         }
601                 }
602
603                 o_mode = mode;
604                 o_name = name;
605         }
606
607         if (has_null_sha1)
608                 retval += report(options, &item->object, FSCK_MSG_NULL_SHA1, "contains entries pointing to null sha1");
609         if (has_full_path)
610                 retval += report(options, &item->object, FSCK_MSG_FULL_PATHNAME, "contains full pathnames");
611         if (has_empty_name)
612                 retval += report(options, &item->object, FSCK_MSG_EMPTY_NAME, "contains empty pathname");
613         if (has_dot)
614                 retval += report(options, &item->object, FSCK_MSG_HAS_DOT, "contains '.'");
615         if (has_dotdot)
616                 retval += report(options, &item->object, FSCK_MSG_HAS_DOTDOT, "contains '..'");
617         if (has_dotgit)
618                 retval += report(options, &item->object, FSCK_MSG_HAS_DOTGIT, "contains '.git'");
619         if (has_zero_pad)
620                 retval += report(options, &item->object, FSCK_MSG_ZERO_PADDED_FILEMODE, "contains zero-padded file modes");
621         if (has_bad_modes)
622                 retval += report(options, &item->object, FSCK_MSG_BAD_FILEMODE, "contains bad file modes");
623         if (has_dup_entries)
624                 retval += report(options, &item->object, FSCK_MSG_DUPLICATE_ENTRIES, "contains duplicate file entries");
625         if (not_properly_sorted)
626                 retval += report(options, &item->object, FSCK_MSG_TREE_NOT_SORTED, "not properly sorted");
627         return retval;
628 }
629
630 static int verify_headers(const void *data, unsigned long size,
631                           struct object *obj, struct fsck_options *options)
632 {
633         const char *buffer = (const char *)data;
634         unsigned long i;
635
636         for (i = 0; i < size; i++) {
637                 switch (buffer[i]) {
638                 case '\0':
639                         return report(options, obj,
640                                 FSCK_MSG_NUL_IN_HEADER,
641                                 "unterminated header: NUL at offset %ld", i);
642                 case '\n':
643                         if (i + 1 < size && buffer[i + 1] == '\n')
644                                 return 0;
645                 }
646         }
647
648         /*
649          * We did not find double-LF that separates the header
650          * and the body.  Not having a body is not a crime but
651          * we do want to see the terminating LF for the last header
652          * line.
653          */
654         if (size && buffer[size - 1] == '\n')
655                 return 0;
656
657         return report(options, obj,
658                 FSCK_MSG_UNTERMINATED_HEADER, "unterminated header");
659 }
660
661 static int fsck_ident(const char **ident, struct object *obj, struct fsck_options *options)
662 {
663         const char *p = *ident;
664         char *end;
665
666         *ident = strchrnul(*ident, '\n');
667         if (**ident == '\n')
668                 (*ident)++;
669
670         if (*p == '<')
671                 return report(options, obj, FSCK_MSG_MISSING_NAME_BEFORE_EMAIL, "invalid author/committer line - missing space before email");
672         p += strcspn(p, "<>\n");
673         if (*p == '>')
674                 return report(options, obj, FSCK_MSG_BAD_NAME, "invalid author/committer line - bad name");
675         if (*p != '<')
676                 return report(options, obj, FSCK_MSG_MISSING_EMAIL, "invalid author/committer line - missing email");
677         if (p[-1] != ' ')
678                 return report(options, obj, FSCK_MSG_MISSING_SPACE_BEFORE_EMAIL, "invalid author/committer line - missing space before email");
679         p++;
680         p += strcspn(p, "<>\n");
681         if (*p != '>')
682                 return report(options, obj, FSCK_MSG_BAD_EMAIL, "invalid author/committer line - bad email");
683         p++;
684         if (*p != ' ')
685                 return report(options, obj, FSCK_MSG_MISSING_SPACE_BEFORE_DATE, "invalid author/committer line - missing space before date");
686         p++;
687         if (*p == '0' && p[1] != ' ')
688                 return report(options, obj, FSCK_MSG_ZERO_PADDED_DATE, "invalid author/committer line - zero-padded date");
689         if (date_overflows(strtoul(p, &end, 10)))
690                 return report(options, obj, FSCK_MSG_BAD_DATE_OVERFLOW, "invalid author/committer line - date causes integer overflow");
691         if ((end == p || *end != ' '))
692                 return report(options, obj, FSCK_MSG_BAD_DATE, "invalid author/committer line - bad date");
693         p = end + 1;
694         if ((*p != '+' && *p != '-') ||
695             !isdigit(p[1]) ||
696             !isdigit(p[2]) ||
697             !isdigit(p[3]) ||
698             !isdigit(p[4]) ||
699             (p[5] != '\n'))
700                 return report(options, obj, FSCK_MSG_BAD_TIMEZONE, "invalid author/committer line - bad time zone");
701         p += 6;
702         return 0;
703 }
704
705 static int fsck_commit_buffer(struct commit *commit, const char *buffer,
706         unsigned long size, struct fsck_options *options)
707 {
708         unsigned char tree_sha1[20], sha1[20];
709         struct commit_graft *graft;
710         unsigned parent_count, parent_line_count = 0, author_count;
711         int err;
712         const char *buffer_begin = buffer;
713
714         if (verify_headers(buffer, size, &commit->object, options))
715                 return -1;
716
717         if (!skip_prefix(buffer, "tree ", &buffer))
718                 return report(options, &commit->object, FSCK_MSG_MISSING_TREE, "invalid format - expected 'tree' line");
719         if (get_sha1_hex(buffer, tree_sha1) || buffer[40] != '\n') {
720                 err = report(options, &commit->object, FSCK_MSG_BAD_TREE_SHA1, "invalid 'tree' line format - bad sha1");
721                 if (err)
722                         return err;
723         }
724         buffer += 41;
725         while (skip_prefix(buffer, "parent ", &buffer)) {
726                 if (get_sha1_hex(buffer, sha1) || buffer[40] != '\n') {
727                         err = report(options, &commit->object, FSCK_MSG_BAD_PARENT_SHA1, "invalid 'parent' line format - bad sha1");
728                         if (err)
729                                 return err;
730                 }
731                 buffer += 41;
732                 parent_line_count++;
733         }
734         graft = lookup_commit_graft(commit->object.oid.hash);
735         parent_count = commit_list_count(commit->parents);
736         if (graft) {
737                 if (graft->nr_parent == -1 && !parent_count)
738                         ; /* shallow commit */
739                 else if (graft->nr_parent != parent_count) {
740                         err = report(options, &commit->object, FSCK_MSG_MISSING_GRAFT, "graft objects missing");
741                         if (err)
742                                 return err;
743                 }
744         } else {
745                 if (parent_count != parent_line_count) {
746                         err = report(options, &commit->object, FSCK_MSG_MISSING_PARENT, "parent objects missing");
747                         if (err)
748                                 return err;
749                 }
750         }
751         author_count = 0;
752         while (skip_prefix(buffer, "author ", &buffer)) {
753                 author_count++;
754                 err = fsck_ident(&buffer, &commit->object, options);
755                 if (err)
756                         return err;
757         }
758         if (author_count < 1)
759                 err = report(options, &commit->object, FSCK_MSG_MISSING_AUTHOR, "invalid format - expected 'author' line");
760         else if (author_count > 1)
761                 err = report(options, &commit->object, FSCK_MSG_MULTIPLE_AUTHORS, "invalid format - multiple 'author' lines");
762         if (err)
763                 return err;
764         if (!skip_prefix(buffer, "committer ", &buffer))
765                 return report(options, &commit->object, FSCK_MSG_MISSING_COMMITTER, "invalid format - expected 'committer' line");
766         err = fsck_ident(&buffer, &commit->object, options);
767         if (err)
768                 return err;
769         if (!commit->tree) {
770                 err = report(options, &commit->object, FSCK_MSG_BAD_TREE, "could not load commit's tree %s", sha1_to_hex(tree_sha1));
771                 if (err)
772                         return err;
773         }
774         if (memchr(buffer_begin, '\0', size)) {
775                 err = report(options, &commit->object, FSCK_MSG_NUL_IN_COMMIT,
776                              "NUL byte in the commit object body");
777                 if (err)
778                         return err;
779         }
780         return 0;
781 }
782
783 static int fsck_commit(struct commit *commit, const char *data,
784         unsigned long size, struct fsck_options *options)
785 {
786         const char *buffer = data ?  data : get_commit_buffer(commit, &size);
787         int ret = fsck_commit_buffer(commit, buffer, size, options);
788         if (!data)
789                 unuse_commit_buffer(commit, buffer);
790         return ret;
791 }
792
793 static int fsck_tag_buffer(struct tag *tag, const char *data,
794         unsigned long size, struct fsck_options *options)
795 {
796         unsigned char sha1[20];
797         int ret = 0;
798         const char *buffer;
799         char *to_free = NULL, *eol;
800         struct strbuf sb = STRBUF_INIT;
801
802         if (data)
803                 buffer = data;
804         else {
805                 enum object_type type;
806
807                 buffer = to_free =
808                         read_sha1_file(tag->object.oid.hash, &type, &size);
809                 if (!buffer)
810                         return report(options, &tag->object,
811                                 FSCK_MSG_MISSING_TAG_OBJECT,
812                                 "cannot read tag object");
813
814                 if (type != OBJ_TAG) {
815                         ret = report(options, &tag->object,
816                                 FSCK_MSG_TAG_OBJECT_NOT_TAG,
817                                 "expected tag got %s",
818                             typename(type));
819                         goto done;
820                 }
821         }
822
823         ret = verify_headers(buffer, size, &tag->object, options);
824         if (ret)
825                 goto done;
826
827         if (!skip_prefix(buffer, "object ", &buffer)) {
828                 ret = report(options, &tag->object, FSCK_MSG_MISSING_OBJECT, "invalid format - expected 'object' line");
829                 goto done;
830         }
831         if (get_sha1_hex(buffer, sha1) || buffer[40] != '\n') {
832                 ret = report(options, &tag->object, FSCK_MSG_BAD_OBJECT_SHA1, "invalid 'object' line format - bad sha1");
833                 if (ret)
834                         goto done;
835         }
836         buffer += 41;
837
838         if (!skip_prefix(buffer, "type ", &buffer)) {
839                 ret = report(options, &tag->object, FSCK_MSG_MISSING_TYPE_ENTRY, "invalid format - expected 'type' line");
840                 goto done;
841         }
842         eol = strchr(buffer, '\n');
843         if (!eol) {
844                 ret = report(options, &tag->object, FSCK_MSG_MISSING_TYPE, "invalid format - unexpected end after 'type' line");
845                 goto done;
846         }
847         if (type_from_string_gently(buffer, eol - buffer, 1) < 0)
848                 ret = report(options, &tag->object, FSCK_MSG_BAD_TYPE, "invalid 'type' value");
849         if (ret)
850                 goto done;
851         buffer = eol + 1;
852
853         if (!skip_prefix(buffer, "tag ", &buffer)) {
854                 ret = report(options, &tag->object, FSCK_MSG_MISSING_TAG_ENTRY, "invalid format - expected 'tag' line");
855                 goto done;
856         }
857         eol = strchr(buffer, '\n');
858         if (!eol) {
859                 ret = report(options, &tag->object, FSCK_MSG_MISSING_TAG, "invalid format - unexpected end after 'type' line");
860                 goto done;
861         }
862         strbuf_addf(&sb, "refs/tags/%.*s", (int)(eol - buffer), buffer);
863         if (check_refname_format(sb.buf, 0)) {
864                 ret = report(options, &tag->object, FSCK_MSG_BAD_TAG_NAME,
865                            "invalid 'tag' name: %.*s",
866                            (int)(eol - buffer), buffer);
867                 if (ret)
868                         goto done;
869         }
870         buffer = eol + 1;
871
872         if (!skip_prefix(buffer, "tagger ", &buffer)) {
873                 /* early tags do not contain 'tagger' lines; warn only */
874                 ret = report(options, &tag->object, FSCK_MSG_MISSING_TAGGER_ENTRY, "invalid format - expected 'tagger' line");
875                 if (ret)
876                         goto done;
877         }
878         else
879                 ret = fsck_ident(&buffer, &tag->object, options);
880
881 done:
882         strbuf_release(&sb);
883         free(to_free);
884         return ret;
885 }
886
887 static int fsck_tag(struct tag *tag, const char *data,
888         unsigned long size, struct fsck_options *options)
889 {
890         struct object *tagged = tag->tagged;
891
892         if (!tagged)
893                 return report(options, &tag->object, FSCK_MSG_BAD_TAG_OBJECT, "could not load tagged object");
894
895         return fsck_tag_buffer(tag, data, size, options);
896 }
897
898 int fsck_object(struct object *obj, void *data, unsigned long size,
899         struct fsck_options *options)
900 {
901         if (!obj)
902                 return report(options, obj, FSCK_MSG_BAD_OBJECT_SHA1, "no valid object to fsck");
903
904         if (obj->type == OBJ_BLOB)
905                 return 0;
906         if (obj->type == OBJ_TREE)
907                 return fsck_tree((struct tree *) obj, options);
908         if (obj->type == OBJ_COMMIT)
909                 return fsck_commit((struct commit *) obj, (const char *) data,
910                         size, options);
911         if (obj->type == OBJ_TAG)
912                 return fsck_tag((struct tag *) obj, (const char *) data,
913                         size, options);
914
915         return report(options, obj, FSCK_MSG_UNKNOWN_TYPE, "unknown type '%d' (internal fsck error)",
916                           obj->type);
917 }
918
919 int fsck_error_function(struct fsck_options *o,
920         struct object *obj, int msg_type, const char *message)
921 {
922         if (msg_type == FSCK_WARN) {
923                 warning("object %s: %s", describe_object(o, obj), message);
924                 return 0;
925         }
926         error("object %s: %s", describe_object(o, obj), message);
927         return 1;
928 }