Adding upstream version 1:2.39.2.upstream/1%2.39.2upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1365 insertions, 0 deletions

diff --git a/fsck.c b/fsck.c
new file mode 100644
index 0000000..47eaeed
--- /dev/null
+++ b/fsck.c
@@ -0,0 +1,1365 @@
+#include "cache.h"
+#include "object-store.h"
+#include "repository.h"
+#include "object.h"
+#include "attr.h"
+#include "blob.h"
+#include "tree.h"
+#include "tree-walk.h"
+#include "commit.h"
+#include "tag.h"
+#include "fsck.h"
+#include "refs.h"
+#include "url.h"
+#include "utf8.h"
+#include "decorate.h"
+#include "oidset.h"
+#include "packfile.h"
+#include "submodule-config.h"
+#include "config.h"
+#include "credential.h"
+#include "help.h"
+
+#define STR(x) #x
+#define MSG_ID(id, msg_type) { STR(id), NULL, NULL, FSCK_##msg_type },
+static struct {
+	const char *id_string;
+	const char *downcased;
+	const char *camelcased;
+	enum fsck_msg_type msg_type;
+} msg_id_info[FSCK_MSG_MAX + 1] = {
+	FOREACH_FSCK_MSG_ID(MSG_ID)
+	{ NULL, NULL, NULL, -1 }
+};
+#undef MSG_ID
+#undef STR
+
+static void prepare_msg_ids(void)
+{
+	int i;
+
+	if (msg_id_info[0].downcased)
+		return;
+
+	/* convert id_string to lower case, without underscores. */
+	for (i = 0; i < FSCK_MSG_MAX; i++) {
+		const char *p = msg_id_info[i].id_string;
+		int len = strlen(p);
+		char *q = xmalloc(len);
+
+		msg_id_info[i].downcased = q;
+		while (*p)
+			if (*p == '_')
+				p++;
+			else
+				*(q)++ = tolower(*(p)++);
+		*q = '\0';
+
+		p = msg_id_info[i].id_string;
+		q = xmalloc(len);
+		msg_id_info[i].camelcased = q;
+		while (*p) {
+			if (*p == '_') {
+				p++;
+				if (*p)
+					*q++ = *p++;
+			} else {
+				*q++ = tolower(*p++);
+			}
+		}
+		*q = '\0';
+	}
+}
+
+static int parse_msg_id(const char *text)
+{
+	int i;
+
+	prepare_msg_ids();
+
+	for (i = 0; i < FSCK_MSG_MAX; i++)
+		if (!strcmp(text, msg_id_info[i].downcased))
+			return i;
+
+	return -1;
+}
+
+void list_config_fsck_msg_ids(struct string_list *list, const char *prefix)
+{
+	int i;
+
+	prepare_msg_ids();
+
+	for (i = 0; i < FSCK_MSG_MAX; i++)
+		list_config_item(list, prefix, msg_id_info[i].camelcased);
+}
+
+static enum fsck_msg_type fsck_msg_type(enum fsck_msg_id msg_id,
+	struct fsck_options *options)
+{
+	assert(msg_id >= 0 && msg_id < FSCK_MSG_MAX);
+
+	if (!options->msg_type) {
+		enum fsck_msg_type msg_type = msg_id_info[msg_id].msg_type;
+
+		if (options->strict && msg_type == FSCK_WARN)
+			msg_type = FSCK_ERROR;
+		return msg_type;
+	}
+
+	return options->msg_type[msg_id];
+}
+
+static enum fsck_msg_type parse_msg_type(const char *str)
+{
+	if (!strcmp(str, "error"))
+		return FSCK_ERROR;
+	else if (!strcmp(str, "warn"))
+		return FSCK_WARN;
+	else if (!strcmp(str, "ignore"))
+		return FSCK_IGNORE;
+	else
+		die("Unknown fsck message type: '%s'", str);
+}
+
+int is_valid_msg_type(const char *msg_id, const char *msg_type)
+{
+	if (parse_msg_id(msg_id) < 0)
+		return 0;
+	parse_msg_type(msg_type);
+	return 1;
+}
+
+void fsck_set_msg_type_from_ids(struct fsck_options *options,
+				enum fsck_msg_id msg_id,
+				enum fsck_msg_type msg_type)
+{
+	if (!options->msg_type) {
+		int i;
+		enum fsck_msg_type *severity;
+		ALLOC_ARRAY(severity, FSCK_MSG_MAX);
+		for (i = 0; i < FSCK_MSG_MAX; i++)
+			severity[i] = fsck_msg_type(i, options);
+		options->msg_type = severity;
+	}
+
+	options->msg_type[msg_id] = msg_type;
+}
+
+void fsck_set_msg_type(struct fsck_options *options,
+		       const char *msg_id_str, const char *msg_type_str)
+{
+	int msg_id = parse_msg_id(msg_id_str);
+	enum fsck_msg_type msg_type = parse_msg_type(msg_type_str);
+
+	if (msg_id < 0)
+		die("Unhandled message id: %s", msg_id_str);
+
+	if (msg_type != FSCK_ERROR && msg_id_info[msg_id].msg_type == FSCK_FATAL)
+		die("Cannot demote %s to %s", msg_id_str, msg_type_str);
+
+	fsck_set_msg_type_from_ids(options, msg_id, msg_type);
+}
+
+void fsck_set_msg_types(struct fsck_options *options, const char *values)
+{
+	char *buf = xstrdup(values), *to_free = buf;
+	int done = 0;
+
+	while (!done) {
+		int len = strcspn(buf, " ,|"), equal;
+
+		done = !buf[len];
+		if (!len) {
+			buf++;
+			continue;
+		}
+		buf[len] = '\0';
+
+		for (equal = 0;
+		     equal < len && buf[equal] != '=' && buf[equal] != ':';
+		     equal++)
+			buf[equal] = tolower(buf[equal]);
+		buf[equal] = '\0';
+
+		if (!strcmp(buf, "skiplist")) {
+			if (equal == len)
+				die("skiplist requires a path");
+			oidset_parse_file(&options->skiplist, buf + equal + 1);
+			buf += len + 1;
+			continue;
+		}
+
+		if (equal == len)
+			die("Missing '=': '%s'", buf);
+
+		fsck_set_msg_type(options, buf, buf + equal + 1);
+		buf += len + 1;
+	}
+	free(to_free);
+}
+
+static int object_on_skiplist(struct fsck_options *opts,
+			      const struct object_id *oid)
+{
+	return opts && oid && oidset_contains(&opts->skiplist, oid);
+}
+
+__attribute__((format (printf, 5, 6)))
+static int report(struct fsck_options *options,
+		  const struct object_id *oid, enum object_type object_type,
+		  enum fsck_msg_id msg_id, const char *fmt, ...)
+{
+	va_list ap;
+	struct strbuf sb = STRBUF_INIT;
+	enum fsck_msg_type msg_type = fsck_msg_type(msg_id, options);
+	int result;
+
+	if (msg_type == FSCK_IGNORE)
+		return 0;
+
+	if (object_on_skiplist(options, oid))
+		return 0;
+
+	if (msg_type == FSCK_FATAL)
+		msg_type = FSCK_ERROR;
+	else if (msg_type == FSCK_INFO)
+		msg_type = FSCK_WARN;
+
+	prepare_msg_ids();
+	strbuf_addf(&sb, "%s: ", msg_id_info[msg_id].camelcased);
+
+	va_start(ap, fmt);
+	strbuf_vaddf(&sb, fmt, ap);
+	result = options->error_func(options, oid, object_type,
+				     msg_type, msg_id, sb.buf);
+	strbuf_release(&sb);
+	va_end(ap);
+
+	return result;
+}
+
+void fsck_enable_object_names(struct fsck_options *options)
+{
+	if (!options->object_names)
+		options->object_names = kh_init_oid_map();
+}
+
+const char *fsck_get_object_name(struct fsck_options *options,
+				 const struct object_id *oid)
+{
+	khiter_t pos;
+	if (!options->object_names)
+		return NULL;
+	pos = kh_get_oid_map(options->object_names, *oid);
+	if (pos >= kh_end(options->object_names))
+		return NULL;
+	return kh_value(options->object_names, pos);
+}
+
+void fsck_put_object_name(struct fsck_options *options,
+			  const struct object_id *oid,
+			  const char *fmt, ...)
+{
+	va_list ap;
+	struct strbuf buf = STRBUF_INIT;
+	khiter_t pos;
+	int hashret;
+
+	if (!options->object_names)
+		return;
+
+	pos = kh_put_oid_map(options->object_names, *oid, &hashret);
+	if (!hashret)
+		return;
+	va_start(ap, fmt);
+	strbuf_vaddf(&buf, fmt, ap);
+	kh_value(options->object_names, pos) = strbuf_detach(&buf, NULL);
+	va_end(ap);
+}
+
+const char *fsck_describe_object(struct fsck_options *options,
+				 const struct object_id *oid)
+{
+	static struct strbuf bufs[] = {
+		STRBUF_INIT, STRBUF_INIT, STRBUF_INIT, STRBUF_INIT
+	};
+	static int b = 0;
+	struct strbuf *buf;
+	const char *name = fsck_get_object_name(options, oid);
+
+	buf = bufs + b;
+	b = (b + 1) % ARRAY_SIZE(bufs);
+	strbuf_reset(buf);
+	strbuf_addstr(buf, oid_to_hex(oid));
+	if (name)
+		strbuf_addf(buf, " (%s)", name);
+
+	return buf->buf;
+}
+
+static int fsck_walk_tree(struct tree *tree, void *data, struct fsck_options *options)
+{
+	struct tree_desc desc;
+	struct name_entry entry;
+	int res = 0;
+	const char *name;
+
+	if (parse_tree(tree))
+		return -1;
+
+	name = fsck_get_object_name(options, &tree->object.oid);
+	if (init_tree_desc_gently(&desc, tree->buffer, tree->size, 0))
+		return -1;
+	while (tree_entry_gently(&desc, &entry)) {
+		struct object *obj;
+		int result;
+
+		if (S_ISGITLINK(entry.mode))
+			continue;
+
+		if (S_ISDIR(entry.mode)) {
+			obj = (struct object *)lookup_tree(the_repository, &entry.oid);
+			if (name && obj)
+				fsck_put_object_name(options, &entry.oid, "%s%s/",
+						     name, entry.path);
+			result = options->walk(obj, OBJ_TREE, data, options);
+		}
+		else if (S_ISREG(entry.mode) || S_ISLNK(entry.mode)) {
+			obj = (struct object *)lookup_blob(the_repository, &entry.oid);
+			if (name && obj)
+				fsck_put_object_name(options, &entry.oid, "%s%s",
+						     name, entry.path);
+			result = options->walk(obj, OBJ_BLOB, data, options);
+		}
+		else {
+			result = error("in tree %s: entry %s has bad mode %.6o",
+				       fsck_describe_object(options, &tree->object.oid),
+				       entry.path, entry.mode);
+		}
+		if (result < 0)
+			return result;
+		if (!res)
+			res = result;
+	}
+	return res;
+}
+
+static int fsck_walk_commit(struct commit *commit, void *data, struct fsck_options *options)
+{
+	int counter = 0, generation = 0, name_prefix_len = 0;
+	struct commit_list *parents;
+	int res;
+	int result;
+	const char *name;
+
+	if (parse_commit(commit))
+		return -1;
+
+	name = fsck_get_object_name(options, &commit->object.oid);
+	if (name)
+		fsck_put_object_name(options, get_commit_tree_oid(commit),
+				     "%s:", name);
+
+	result = options->walk((struct object *)get_commit_tree(commit),
+			       OBJ_TREE, data, options);
+	if (result < 0)
+		return result;
+	res = result;
+
+	parents = commit->parents;
+	if (name && parents) {
+		int len = strlen(name), power;
+
+		if (len && name[len - 1] == '^') {
+			generation = 1;
+			name_prefix_len = len - 1;
+		}
+		else { /* parse ~<generation> suffix */
+			for (generation = 0, power = 1;
+			     len && isdigit(name[len - 1]);
+			     power *= 10)
+				generation += power * (name[--len] - '0');
+			if (power > 1 && len && name[len - 1] == '~')
+				name_prefix_len = len - 1;
+			else {
+				/* Maybe a non-first parent, e.g. HEAD^2 */
+				generation = 0;
+				name_prefix_len = len;
+			}
+		}
+	}
+
+	while (parents) {
+		if (name) {
+			struct object_id *oid = &parents->item->object.oid;
+
+			if (counter++)
+				fsck_put_object_name(options, oid, "%s^%d",
+						     name, counter);
+			else if (generation > 0)
+				fsck_put_object_name(options, oid, "%.*s~%d",
+						     name_prefix_len, name,
+						     generation + 1);
+			else
+				fsck_put_object_name(options, oid, "%s^", name);
+		}
+		result = options->walk((struct object *)parents->item, OBJ_COMMIT, data, options);
+		if (result < 0)
+			return result;
+		if (!res)
+			res = result;
+		parents = parents->next;
+	}
+	return res;
+}
+
+static int fsck_walk_tag(struct tag *tag, void *data, struct fsck_options *options)
+{
+	const char *name = fsck_get_object_name(options, &tag->object.oid);
+
+	if (parse_tag(tag))
+		return -1;
+	if (name)
+		fsck_put_object_name(options, &tag->tagged->oid, "%s", name);
+	return options->walk(tag->tagged, OBJ_ANY, data, options);
+}
+
+int fsck_walk(struct object *obj, void *data, struct fsck_options *options)
+{
+	if (!obj)
+		return -1;
+
+	if (obj->type == OBJ_NONE)
+		parse_object(the_repository, &obj->oid);
+
+	switch (obj->type) {
+	case OBJ_BLOB:
+		return 0;
+	case OBJ_TREE:
+		return fsck_walk_tree((struct tree *)obj, data, options);
+	case OBJ_COMMIT:
+		return fsck_walk_commit((struct commit *)obj, data, options);
+	case OBJ_TAG:
+		return fsck_walk_tag((struct tag *)obj, data, options);
+	default:
+		error("Unknown object type for %s",
+		      fsck_describe_object(options, &obj->oid));
+		return -1;
+	}
+}
+
+struct name_stack {
+	const char **names;
+	size_t nr, alloc;
+};
+
+static void name_stack_push(struct name_stack *stack, const char *name)
+{
+	ALLOC_GROW(stack->names, stack->nr + 1, stack->alloc);
+	stack->names[stack->nr++] = name;
+}
+
+static const char *name_stack_pop(struct name_stack *stack)
+{
+	return stack->nr ? stack->names[--stack->nr] : NULL;
+}
+
+static void name_stack_clear(struct name_stack *stack)
+{
+	FREE_AND_NULL(stack->names);
+	stack->nr = stack->alloc = 0;
+}
+
+/*
+ * The entries in a tree are ordered in the _path_ order,
+ * which means that a directory entry is ordered by adding
+ * a slash to the end of it.
+ *
+ * So a directory called "a" is ordered _after_ a file
+ * called "a.c", because "a/" sorts after "a.c".
+ */
+#define TREE_UNORDERED (-1)
+#define TREE_HAS_DUPS  (-2)
+
+static int is_less_than_slash(unsigned char c)
+{
+	return '\0' < c && c < '/';
+}
+
+static int verify_ordered(unsigned mode1, const char *name1,
+			  unsigned mode2, const char *name2,
+			  struct name_stack *candidates)
+{
+	int len1 = strlen(name1);
+	int len2 = strlen(name2);
+	int len = len1 < len2 ? len1 : len2;
+	unsigned char c1, c2;
+	int cmp;
+
+	cmp = memcmp(name1, name2, len);
+	if (cmp < 0)
+		return 0;
+	if (cmp > 0)
+		return TREE_UNORDERED;
+
+	/*
+	 * Ok, the first <len> characters are the same.
+	 * Now we need to order the next one, but turn
+	 * a '\0' into a '/' for a directory entry.
+	 */
+	c1 = name1[len];
+	c2 = name2[len];
+	if (!c1 && !c2)
+		/*
+		 * git-write-tree used to write out a nonsense tree that has
+		 * entries with the same name, one blob and one tree.  Make
+		 * sure we do not have duplicate entries.
+		 */
+		return TREE_HAS_DUPS;
+	if (!c1 && S_ISDIR(mode1))
+		c1 = '/';
+	if (!c2 && S_ISDIR(mode2))
+		c2 = '/';
+
+	/*
+	 * There can be non-consecutive duplicates due to the implicitly
+	 * added slash, e.g.:
+	 *
+	 *   foo
+	 *   foo.bar
+	 *   foo.bar.baz
+	 *   foo.bar/
+	 *   foo/
+	 *
+	 * Record non-directory candidates (like "foo" and "foo.bar" in
+	 * the example) on a stack and check directory candidates (like
+	 * foo/" and "foo.bar/") against that stack.
+	 */
+	if (!c1 && is_less_than_slash(c2)) {
+		name_stack_push(candidates, name1);
+	} else if (c2 == '/' && is_less_than_slash(c1)) {
+		for (;;) {
+			const char *p;
+			const char *f_name = name_stack_pop(candidates);
+
+			if (!f_name)
+				break;
+			if (!skip_prefix(name2, f_name, &p))
+				continue;
+			if (!*p)
+				return TREE_HAS_DUPS;
+			if (is_less_than_slash(*p)) {
+				name_stack_push(candidates, f_name);
+				break;
+			}
+		}
+	}
+
+	return c1 < c2 ? 0 : TREE_UNORDERED;
+}
+
+static int fsck_tree(const struct object_id *tree_oid,
+		     const char *buffer, unsigned long size,
+		     struct fsck_options *options)
+{
+	int retval = 0;
+	int has_null_sha1 = 0;
+	int has_full_path = 0;
+	int has_empty_name = 0;
+	int has_dot = 0;
+	int has_dotdot = 0;
+	int has_dotgit = 0;
+	int has_zero_pad = 0;
+	int has_bad_modes = 0;
+	int has_dup_entries = 0;
+	int not_properly_sorted = 0;
+	struct tree_desc desc;
+	unsigned o_mode;
+	const char *o_name;
+	struct name_stack df_dup_candidates = { NULL };
+
+	if (init_tree_desc_gently(&desc, buffer, size, TREE_DESC_RAW_MODES)) {
+		retval += report(options, tree_oid, OBJ_TREE,
+				 FSCK_MSG_BAD_TREE,
+				 "cannot be parsed as a tree");
+		return retval;
+	}
+
+	o_mode = 0;
+	o_name = NULL;
+
+	while (desc.size) {
+		unsigned short mode;
+		const char *name, *backslash;
+		const struct object_id *entry_oid;
+
+		entry_oid = tree_entry_extract(&desc, &name, &mode);
+
+		has_null_sha1 |= is_null_oid(entry_oid);
+		has_full_path |= !!strchr(name, '/');
+		has_empty_name |= !*name;
+		has_dot |= !strcmp(name, ".");
+		has_dotdot |= !strcmp(name, "..");
+		has_dotgit |= is_hfs_dotgit(name) || is_ntfs_dotgit(name);
+		has_zero_pad |= *(char *)desc.buffer == '0';
+
+		if (is_hfs_dotgitmodules(name) || is_ntfs_dotgitmodules(name)) {
+			if (!S_ISLNK(mode))
+				oidset_insert(&options->gitmodules_found,
+					      entry_oid);
+			else
+				retval += report(options,
+						 tree_oid, OBJ_TREE,
+						 FSCK_MSG_GITMODULES_SYMLINK,
+						 ".gitmodules is a symbolic link");
+		}
+
+		if (is_hfs_dotgitattributes(name) || is_ntfs_dotgitattributes(name)) {
+			if (!S_ISLNK(mode))
+				oidset_insert(&options->gitattributes_found,
+					      entry_oid);
+			else
+				retval += report(options, tree_oid, OBJ_TREE,
+						 FSCK_MSG_GITATTRIBUTES_SYMLINK,
+						 ".gitattributes is a symlink");
+		}
+
+		if (S_ISLNK(mode)) {
+			if (is_hfs_dotgitignore(name) ||
+			    is_ntfs_dotgitignore(name))
+				retval += report(options, tree_oid, OBJ_TREE,
+						 FSCK_MSG_GITIGNORE_SYMLINK,
+						 ".gitignore is a symlink");
+			if (is_hfs_dotmailmap(name) ||
+			    is_ntfs_dotmailmap(name))
+				retval += report(options, tree_oid, OBJ_TREE,
+						 FSCK_MSG_MAILMAP_SYMLINK,
+						 ".mailmap is a symlink");
+		}
+
+		if ((backslash = strchr(name, '\\'))) {
+			while (backslash) {
+				backslash++;
+				has_dotgit |= is_ntfs_dotgit(backslash);
+				if (is_ntfs_dotgitmodules(backslash)) {
+					if (!S_ISLNK(mode))
+						oidset_insert(&options->gitmodules_found,
+							      entry_oid);
+					else
+						retval += report(options, tree_oid, OBJ_TREE,
+								 FSCK_MSG_GITMODULES_SYMLINK,
+								 ".gitmodules is a symbolic link");
+				}
+				backslash = strchr(backslash, '\\');
+			}
+		}
+
+		if (update_tree_entry_gently(&desc)) {
+			retval += report(options, tree_oid, OBJ_TREE,
+					 FSCK_MSG_BAD_TREE,
+					 "cannot be parsed as a tree");
+			break;
+		}
+
+		switch (mode) {
+		/*
+		 * Standard modes..
+		 */
+		case S_IFREG | 0755:
+		case S_IFREG | 0644:
+		case S_IFLNK:
+		case S_IFDIR:
+		case S_IFGITLINK:
+			break;
+		/*
+		 * This is nonstandard, but we had a few of these
+		 * early on when we honored the full set of mode
+		 * bits..
+		 */
+		case S_IFREG | 0664:
+			if (!options->strict)
+				break;
+			/* fallthrough */
+		default:
+			has_bad_modes = 1;
+		}
+
+		if (o_name) {
+			switch (verify_ordered(o_mode, o_name, mode, name,
+					       &df_dup_candidates)) {
+			case TREE_UNORDERED:
+				not_properly_sorted = 1;
+				break;
+			case TREE_HAS_DUPS:
+				has_dup_entries = 1;
+				break;
+			default:
+				break;
+			}
+		}
+
+		o_mode = mode;
+		o_name = name;
+	}
+
+	name_stack_clear(&df_dup_candidates);
+
+	if (has_null_sha1)
+		retval += report(options, tree_oid, OBJ_TREE,
+				 FSCK_MSG_NULL_SHA1,
+				 "contains entries pointing to null sha1");
+	if (has_full_path)
+		retval += report(options, tree_oid, OBJ_TREE,
+				 FSCK_MSG_FULL_PATHNAME,
+				 "contains full pathnames");
+	if (has_empty_name)
+		retval += report(options, tree_oid, OBJ_TREE,
+				 FSCK_MSG_EMPTY_NAME,
+				 "contains empty pathname");
+	if (has_dot)
+		retval += report(options, tree_oid, OBJ_TREE,
+				 FSCK_MSG_HAS_DOT,
+				 "contains '.'");
+	if (has_dotdot)
+		retval += report(options, tree_oid, OBJ_TREE,
+				 FSCK_MSG_HAS_DOTDOT,
+				 "contains '..'");
+	if (has_dotgit)
+		retval += report(options, tree_oid, OBJ_TREE,
+				 FSCK_MSG_HAS_DOTGIT,
+				 "contains '.git'");
+	if (has_zero_pad)
+		retval += report(options, tree_oid, OBJ_TREE,
+				 FSCK_MSG_ZERO_PADDED_FILEMODE,
+				 "contains zero-padded file modes");
+	if (has_bad_modes)
+		retval += report(options, tree_oid, OBJ_TREE,
+				 FSCK_MSG_BAD_FILEMODE,
+				 "contains bad file modes");
+	if (has_dup_entries)
+		retval += report(options, tree_oid, OBJ_TREE,
+				 FSCK_MSG_DUPLICATE_ENTRIES,
+				 "contains duplicate file entries");
+	if (not_properly_sorted)
+		retval += report(options, tree_oid, OBJ_TREE,
+				 FSCK_MSG_TREE_NOT_SORTED,
+				 "not properly sorted");
+	return retval;
+}
+
+static int verify_headers(const void *data, unsigned long size,
+			  const struct object_id *oid, enum object_type type,
+			  struct fsck_options *options)
+{
+	const char *buffer = (const char *)data;
+	unsigned long i;
+
+	for (i = 0; i < size; i++) {
+		switch (buffer[i]) {
+		case '\0':
+			return report(options, oid, type,
+				FSCK_MSG_NUL_IN_HEADER,
+				"unterminated header: NUL at offset %ld", i);
+		case '\n':
+			if (i + 1 < size && buffer[i + 1] == '\n')
+				return 0;
+		}
+	}
+
+	/*
+	 * We did not find double-LF that separates the header
+	 * and the body.  Not having a body is not a crime but
+	 * we do want to see the terminating LF for the last header
+	 * line.
+	 */
+	if (size && buffer[size - 1] == '\n')
+		return 0;
+
+	return report(options, oid, type,
+		FSCK_MSG_UNTERMINATED_HEADER, "unterminated header");
+}
+
+static int fsck_ident(const char **ident,
+		      const struct object_id *oid, enum object_type type,
+		      struct fsck_options *options)
+{
+	const char *p = *ident;
+	char *end;
+
+	*ident = strchrnul(*ident, '\n');
+	if (**ident == '\n')
+		(*ident)++;
+
+	if (*p == '<')
+		return report(options, oid, type, FSCK_MSG_MISSING_NAME_BEFORE_EMAIL, "invalid author/committer line - missing space before email");
+	p += strcspn(p, "<>\n");
+	if (*p == '>')
+		return report(options, oid, type, FSCK_MSG_BAD_NAME, "invalid author/committer line - bad name");
+	if (*p != '<')
+		return report(options, oid, type, FSCK_MSG_MISSING_EMAIL, "invalid author/committer line - missing email");
+	if (p[-1] != ' ')
+		return report(options, oid, type, FSCK_MSG_MISSING_SPACE_BEFORE_EMAIL, "invalid author/committer line - missing space before email");
+	p++;
+	p += strcspn(p, "<>\n");
+	if (*p != '>')
+		return report(options, oid, type, FSCK_MSG_BAD_EMAIL, "invalid author/committer line - bad email");
+	p++;
+	if (*p != ' ')
+		return report(options, oid, type, FSCK_MSG_MISSING_SPACE_BEFORE_DATE, "invalid author/committer line - missing space before date");
+	p++;
+	if (*p == '0' && p[1] != ' ')
+		return report(options, oid, type, FSCK_MSG_ZERO_PADDED_DATE, "invalid author/committer line - zero-padded date");
+	if (date_overflows(parse_timestamp(p, &end, 10)))
+		return report(options, oid, type, FSCK_MSG_BAD_DATE_OVERFLOW, "invalid author/committer line - date causes integer overflow");
+	if ((end == p || *end != ' '))
+		return report(options, oid, type, FSCK_MSG_BAD_DATE, "invalid author/committer line - bad date");
+	p = end + 1;
+	if ((*p != '+' && *p != '-') ||
+	    !isdigit(p[1]) ||
+	    !isdigit(p[2]) ||
+	    !isdigit(p[3]) ||
+	    !isdigit(p[4]) ||
+	    (p[5] != '\n'))
+		return report(options, oid, type, FSCK_MSG_BAD_TIMEZONE, "invalid author/committer line - bad time zone");
+	p += 6;
+	return 0;
+}
+
+static int fsck_commit(const struct object_id *oid,
+		       const char *buffer, unsigned long size,
+		       struct fsck_options *options)
+{
+	struct object_id tree_oid, parent_oid;
+	unsigned author_count;
+	int err;
+	const char *buffer_begin = buffer;
+	const char *p;
+
+	if (verify_headers(buffer, size, oid, OBJ_COMMIT, options))
+		return -1;
+
+	if (!skip_prefix(buffer, "tree ", &buffer))
+		return report(options, oid, OBJ_COMMIT, FSCK_MSG_MISSING_TREE, "invalid format - expected 'tree' line");
+	if (parse_oid_hex(buffer, &tree_oid, &p) || *p != '\n') {
+		err = report(options, oid, OBJ_COMMIT, FSCK_MSG_BAD_TREE_SHA1, "invalid 'tree' line format - bad sha1");
+		if (err)
+			return err;
+	}
+	buffer = p + 1;
+	while (skip_prefix(buffer, "parent ", &buffer)) {
+		if (parse_oid_hex(buffer, &parent_oid, &p) || *p != '\n') {
+			err = report(options, oid, OBJ_COMMIT, FSCK_MSG_BAD_PARENT_SHA1, "invalid 'parent' line format - bad sha1");
+			if (err)
+				return err;
+		}
+		buffer = p + 1;
+	}
+	author_count = 0;
+	while (skip_prefix(buffer, "author ", &buffer)) {
+		author_count++;
+		err = fsck_ident(&buffer, oid, OBJ_COMMIT, options);
+		if (err)
+			return err;
+	}
+	if (author_count < 1)
+		err = report(options, oid, OBJ_COMMIT, FSCK_MSG_MISSING_AUTHOR, "invalid format - expected 'author' line");
+	else if (author_count > 1)
+		err = report(options, oid, OBJ_COMMIT, FSCK_MSG_MULTIPLE_AUTHORS, "invalid format - multiple 'author' lines");
+	if (err)
+		return err;
+	if (!skip_prefix(buffer, "committer ", &buffer))
+		return report(options, oid, OBJ_COMMIT, FSCK_MSG_MISSING_COMMITTER, "invalid format - expected 'committer' line");
+	err = fsck_ident(&buffer, oid, OBJ_COMMIT, options);
+	if (err)
+		return err;
+	if (memchr(buffer_begin, '\0', size)) {
+		err = report(options, oid, OBJ_COMMIT, FSCK_MSG_NUL_IN_COMMIT,
+			     "NUL byte in the commit object body");
+		if (err)
+			return err;
+	}
+	return 0;
+}
+
+static int fsck_tag(const struct object_id *oid, const char *buffer,
+		    unsigned long size, struct fsck_options *options)
+{
+	struct object_id tagged_oid;
+	int tagged_type;
+	return fsck_tag_standalone(oid, buffer, size, options, &tagged_oid,
+				   &tagged_type);
+}
+
+int fsck_tag_standalone(const struct object_id *oid, const char *buffer,
+			unsigned long size, struct fsck_options *options,
+			struct object_id *tagged_oid,
+			int *tagged_type)
+{
+	int ret = 0;
+	char *eol;
+	struct strbuf sb = STRBUF_INIT;
+	const char *p;
+
+	ret = verify_headers(buffer, size, oid, OBJ_TAG, options);
+	if (ret)
+		goto done;
+
+	if (!skip_prefix(buffer, "object ", &buffer)) {
+		ret = report(options, oid, OBJ_TAG, FSCK_MSG_MISSING_OBJECT, "invalid format - expected 'object' line");
+		goto done;
+	}
+	if (parse_oid_hex(buffer, tagged_oid, &p) || *p != '\n') {
+		ret = report(options, oid, OBJ_TAG, FSCK_MSG_BAD_OBJECT_SHA1, "invalid 'object' line format - bad sha1");
+		if (ret)
+			goto done;
+	}
+	buffer = p + 1;
+
+	if (!skip_prefix(buffer, "type ", &buffer)) {
+		ret = report(options, oid, OBJ_TAG, FSCK_MSG_MISSING_TYPE_ENTRY, "invalid format - expected 'type' line");
+		goto done;
+	}
+	eol = strchr(buffer, '\n');
+	if (!eol) {
+		ret = report(options, oid, OBJ_TAG, FSCK_MSG_MISSING_TYPE, "invalid format - unexpected end after 'type' line");
+		goto done;
+	}
+	*tagged_type = type_from_string_gently(buffer, eol - buffer, 1);
+	if (*tagged_type < 0)
+		ret = report(options, oid, OBJ_TAG, FSCK_MSG_BAD_TYPE, "invalid 'type' value");
+	if (ret)
+		goto done;
+	buffer = eol + 1;
+
+	if (!skip_prefix(buffer, "tag ", &buffer)) {
+		ret = report(options, oid, OBJ_TAG, FSCK_MSG_MISSING_TAG_ENTRY, "invalid format - expected 'tag' line");
+		goto done;
+	}
+	eol = strchr(buffer, '\n');
+	if (!eol) {
+		ret = report(options, oid, OBJ_TAG, FSCK_MSG_MISSING_TAG, "invalid format - unexpected end after 'type' line");
+		goto done;
+	}
+	strbuf_addf(&sb, "refs/tags/%.*s", (int)(eol - buffer), buffer);
+	if (check_refname_format(sb.buf, 0)) {
+		ret = report(options, oid, OBJ_TAG,
+			     FSCK_MSG_BAD_TAG_NAME,
+			     "invalid 'tag' name: %.*s",
+			     (int)(eol - buffer), buffer);
+		if (ret)
+			goto done;
+	}
+	buffer = eol + 1;
+
+	if (!skip_prefix(buffer, "tagger ", &buffer)) {
+		/* early tags do not contain 'tagger' lines; warn only */
+		ret = report(options, oid, OBJ_TAG, FSCK_MSG_MISSING_TAGGER_ENTRY, "invalid format - expected 'tagger' line");
+		if (ret)
+			goto done;
+	}
+	else
+		ret = fsck_ident(&buffer, oid, OBJ_TAG, options);
+	if (!*buffer)
+		goto done;
+
+	if (!starts_with(buffer, "\n")) {
+		/*
+		 * The verify_headers() check will allow
+		 * e.g. "[...]tagger <tagger>\nsome
+		 * garbage\n\nmessage" to pass, thinking "some
+		 * garbage" could be a custom header. E.g. "mktag"
+		 * doesn't want any unknown headers.
+		 */
+		ret = report(options, oid, OBJ_TAG, FSCK_MSG_EXTRA_HEADER_ENTRY, "invalid format - extra header(s) after 'tagger'");
+		if (ret)
+			goto done;
+	}
+
+done:
+	strbuf_release(&sb);
+	return ret;
+}
+
+static int starts_with_dot_slash(const char *const path)
+{
+	return path_match_flags(path, PATH_MATCH_STARTS_WITH_DOT_SLASH |
+				PATH_MATCH_XPLATFORM);
+}
+
+static int starts_with_dot_dot_slash(const char *const path)
+{
+	return path_match_flags(path, PATH_MATCH_STARTS_WITH_DOT_DOT_SLASH |
+				PATH_MATCH_XPLATFORM);
+}
+
+static int submodule_url_is_relative(const char *url)
+{
+	return starts_with_dot_slash(url) || starts_with_dot_dot_slash(url);
+}
+
+/*
+ * Count directory components that a relative submodule URL should chop
+ * from the remote_url it is to be resolved against.
+ *
+ * In other words, this counts "../" components at the start of a
+ * submodule URL.
+ *
+ * Returns the number of directory components to chop and writes a
+ * pointer to the next character of url after all leading "./" and
+ * "../" components to out.
+ */
+static int count_leading_dotdots(const char *url, const char **out)
+{
+	int result = 0;
+	while (1) {
+		if (starts_with_dot_dot_slash(url)) {
+			result++;
+			url += strlen("../");
+			continue;
+		}
+		if (starts_with_dot_slash(url)) {
+			url += strlen("./");
+			continue;
+		}
+		*out = url;
+		return result;
+	}
+}
+/*
+ * Check whether a transport is implemented by git-remote-curl.
+ *
+ * If it is, returns 1 and writes the URL that would be passed to
+ * git-remote-curl to the "out" parameter.
+ *
+ * Otherwise, returns 0 and leaves "out" untouched.
+ *
+ * Examples:
+ *   http::https://example.com/repo.git -> 1, https://example.com/repo.git
+ *   https://example.com/repo.git -> 1, https://example.com/repo.git
+ *   git://example.com/repo.git -> 0
+ *
+ * This is for use in checking for previously exploitable bugs that
+ * required a submodule URL to be passed to git-remote-curl.
+ */
+static int url_to_curl_url(const char *url, const char **out)
+{
+	/*
+	 * We don't need to check for case-aliases, "http.exe", and so
+	 * on because in the default configuration, is_transport_allowed
+	 * prevents URLs with those schemes from being cloned
+	 * automatically.
+	 */
+	if (skip_prefix(url, "http::", out) ||
+	    skip_prefix(url, "https::", out) ||
+	    skip_prefix(url, "ftp::", out) ||
+	    skip_prefix(url, "ftps::", out))
+		return 1;
+	if (starts_with(url, "http://") ||
+	    starts_with(url, "https://") ||
+	    starts_with(url, "ftp://") ||
+	    starts_with(url, "ftps://")) {
+		*out = url;
+		return 1;
+	}
+	return 0;
+}
+
+static int check_submodule_url(const char *url)
+{
+	const char *curl_url;
+
+	if (looks_like_command_line_option(url))
+		return -1;
+
+	if (submodule_url_is_relative(url) || starts_with(url, "git://")) {
+		char *decoded;
+		const char *next;
+		int has_nl;
+
+		/*
+		 * This could be appended to an http URL and url-decoded;
+		 * check for malicious characters.
+		 */
+		decoded = url_decode(url);
+		has_nl = !!strchr(decoded, '\n');
+
+		free(decoded);
+		if (has_nl)
+			return -1;
+
+		/*
+		 * URLs which escape their root via "../" can overwrite
+		 * the host field and previous components, resolving to
+		 * URLs like https::example.com/submodule.git and
+		 * https:///example.com/submodule.git that were
+		 * susceptible to CVE-2020-11008.
+		 */
+		if (count_leading_dotdots(url, &next) > 0 &&
+		    (*next == ':' || *next == '/'))
+			return -1;
+	}
+
+	else if (url_to_curl_url(url, &curl_url)) {
+		struct credential c = CREDENTIAL_INIT;
+		int ret = 0;
+		if (credential_from_url_gently(&c, curl_url, 1) ||
+		    !*c.host)
+			ret = -1;
+		credential_clear(&c);
+		return ret;
+	}
+
+	return 0;
+}
+
+struct fsck_gitmodules_data {
+	const struct object_id *oid;
+	struct fsck_options *options;
+	int ret;
+};
+
+static int fsck_gitmodules_fn(const char *var, const char *value, void *vdata)
+{
+	struct fsck_gitmodules_data *data = vdata;
+	const char *subsection, *key;
+	size_t subsection_len;
+	char *name;
+
+	if (parse_config_key(var, "submodule", &subsection, &subsection_len, &key) < 0 ||
+	    !subsection)
+		return 0;
+
+	name = xmemdupz(subsection, subsection_len);
+	if (check_submodule_name(name) < 0)
+		data->ret |= report(data->options,
+				    data->oid, OBJ_BLOB,
+				    FSCK_MSG_GITMODULES_NAME,
+				    "disallowed submodule name: %s",
+				    name);
+	if (!strcmp(key, "url") && value &&
+	    check_submodule_url(value) < 0)
+		data->ret |= report(data->options,
+				    data->oid, OBJ_BLOB,
+				    FSCK_MSG_GITMODULES_URL,
+				    "disallowed submodule url: %s",
+				    value);
+	if (!strcmp(key, "path") && value &&
+	    looks_like_command_line_option(value))
+		data->ret |= report(data->options,
+				    data->oid, OBJ_BLOB,
+				    FSCK_MSG_GITMODULES_PATH,
+				    "disallowed submodule path: %s",
+				    value);
+	if (!strcmp(key, "update") && value &&
+	    parse_submodule_update_type(value) == SM_UPDATE_COMMAND)
+		data->ret |= report(data->options, data->oid, OBJ_BLOB,
+				    FSCK_MSG_GITMODULES_UPDATE,
+				    "disallowed submodule update setting: %s",
+				    value);
+	free(name);
+
+	return 0;
+}
+
+static int fsck_blob(const struct object_id *oid, const char *buf,
+		     unsigned long size, struct fsck_options *options)
+{
+	int ret = 0;
+
+	if (object_on_skiplist(options, oid))
+		return 0;
+
+	if (oidset_contains(&options->gitmodules_found, oid)) {
+		struct config_options config_opts = { 0 };
+		struct fsck_gitmodules_data data;
+
+		oidset_insert(&options->gitmodules_done, oid);
+
+		if (!buf) {
+			/*
+			 * A missing buffer here is a sign that the caller found the
+			 * blob too gigantic to load into memory. Let's just consider
+			 * that an error.
+			 */
+			return report(options, oid, OBJ_BLOB,
+					FSCK_MSG_GITMODULES_LARGE,
+					".gitmodules too large to parse");
+		}
+
+		data.oid = oid;
+		data.options = options;
+		data.ret = 0;
+		config_opts.error_action = CONFIG_ERROR_SILENT;
+		if (git_config_from_mem(fsck_gitmodules_fn, CONFIG_ORIGIN_BLOB,
+					".gitmodules", buf, size, &data, &config_opts))
+			data.ret |= report(options, oid, OBJ_BLOB,
+					FSCK_MSG_GITMODULES_PARSE,
+					"could not parse gitmodules blob");
+		ret |= data.ret;
+	}
+
+	if (oidset_contains(&options->gitattributes_found, oid)) {
+		const char *ptr;
+
+		oidset_insert(&options->gitattributes_done, oid);
+
+		if (!buf || size > ATTR_MAX_FILE_SIZE) {
+			/*
+			 * A missing buffer here is a sign that the caller found the
+			 * blob too gigantic to load into memory. Let's just consider
+			 * that an error.
+			 */
+			return report(options, oid, OBJ_BLOB,
+					FSCK_MSG_GITATTRIBUTES_LARGE,
+					".gitattributes too large to parse");
+		}
+
+		for (ptr = buf; *ptr; ) {
+			const char *eol = strchrnul(ptr, '\n');
+			if (eol - ptr >= ATTR_MAX_LINE_LENGTH) {
+				ret |= report(options, oid, OBJ_BLOB,
+					      FSCK_MSG_GITATTRIBUTES_LINE_LENGTH,
+					      ".gitattributes has too long lines to parse");
+				break;
+			}
+
+			ptr = *eol ? eol + 1 : eol;
+		}
+	}
+
+	return ret;
+}
+
+int fsck_object(struct object *obj, void *data, unsigned long size,
+	struct fsck_options *options)
+{
+	if (!obj)
+		return report(options, NULL, OBJ_NONE, FSCK_MSG_BAD_OBJECT_SHA1, "no valid object to fsck");
+
+	if (obj->type == OBJ_BLOB)
+		return fsck_blob(&obj->oid, data, size, options);
+	if (obj->type == OBJ_TREE)
+		return fsck_tree(&obj->oid, data, size, options);
+	if (obj->type == OBJ_COMMIT)
+		return fsck_commit(&obj->oid, data, size, options);
+	if (obj->type == OBJ_TAG)
+		return fsck_tag(&obj->oid, data, size, options);
+
+	return report(options, &obj->oid, obj->type,
+		      FSCK_MSG_UNKNOWN_TYPE,
+		      "unknown type '%d' (internal fsck error)",
+		      obj->type);
+}
+
+int fsck_error_function(struct fsck_options *o,
+			const struct object_id *oid,
+			enum object_type object_type,
+			enum fsck_msg_type msg_type,
+			enum fsck_msg_id msg_id,
+			const char *message)
+{
+	if (msg_type == FSCK_WARN) {
+		warning("object %s: %s", fsck_describe_object(o, oid), message);
+		return 0;
+	}
+	error("object %s: %s", fsck_describe_object(o, oid), message);
+	return 1;
+}
+
+static int fsck_blobs(struct oidset *blobs_found, struct oidset *blobs_done,
+		      enum fsck_msg_id msg_missing, enum fsck_msg_id msg_type,
+		      struct fsck_options *options, const char *blob_type)
+{
+	int ret = 0;
+	struct oidset_iter iter;
+	const struct object_id *oid;
+
+	oidset_iter_init(blobs_found, &iter);
+	while ((oid = oidset_iter_next(&iter))) {
+		enum object_type type;
+		unsigned long size;
+		char *buf;
+
+		if (oidset_contains(blobs_done, oid))
+			continue;
+
+		buf = read_object_file(oid, &type, &size);
+		if (!buf) {
+			if (is_promisor_object(oid))
+				continue;
+			ret |= report(options,
+				      oid, OBJ_BLOB, msg_missing,
+				      "unable to read %s blob", blob_type);
+			continue;
+		}
+
+		if (type == OBJ_BLOB)
+			ret |= fsck_blob(oid, buf, size, options);
+		else
+			ret |= report(options, oid, type, msg_type,
+				      "non-blob found at %s", blob_type);
+		free(buf);
+	}
+
+	oidset_clear(blobs_found);
+	oidset_clear(blobs_done);
+
+	return ret;
+}
+
+int fsck_finish(struct fsck_options *options)
+{
+	int ret = 0;
+
+	ret |= fsck_blobs(&options->gitmodules_found, &options->gitmodules_done,
+			  FSCK_MSG_GITMODULES_MISSING, FSCK_MSG_GITMODULES_BLOB,
+			  options, ".gitmodules");
+	ret |= fsck_blobs(&options->gitattributes_found, &options->gitattributes_done,
+			  FSCK_MSG_GITATTRIBUTES_MISSING, FSCK_MSG_GITATTRIBUTES_BLOB,
+			  options, ".gitattributes");
+
+	return ret;
+}
+
+int git_fsck_config(const char *var, const char *value, void *cb)
+{
+	struct fsck_options *options = cb;
+	if (strcmp(var, "fsck.skiplist") == 0) {
+		const char *path;
+		struct strbuf sb = STRBUF_INIT;
+
+		if (git_config_pathname(&path, var, value))
+			return 1;
+		strbuf_addf(&sb, "skiplist=%s", path);
+		free((char *)path);
+		fsck_set_msg_types(options, sb.buf);
+		strbuf_release(&sb);
+		return 0;
+	}
+
+	if (skip_prefix(var, "fsck.", &var)) {
+		fsck_set_msg_type(options, var, value);
+		return 0;
+	}
+
+	return git_default_config(var, value, cb);
+}
+
+/*
+ * Custom error callbacks that are used in more than one place.
+ */
+
+int fsck_error_cb_print_missing_gitmodules(struct fsck_options *o,
+					   const struct object_id *oid,
+					   enum object_type object_type,
+					   enum fsck_msg_type msg_type,
+					   enum fsck_msg_id msg_id,
+					   const char *message)
+{
+	if (msg_id == FSCK_MSG_GITMODULES_MISSING) {
+		puts(oid_to_hex(oid));
+		return 0;
+	}
+	return fsck_error_function(o, oid, object_type, msg_type, msg_id, message);
+}