]> wimlib.net Git - wimlib/blobdiff - src/dentry.c
registry: avoid negating INT32_MIN
[wimlib] / src / dentry.c
index 01945b2a33062b80b8a53f1c830ab8441d30795e..9e175f7ea5391841ca95e8e26be574e7894b77ac 100644 (file)
@@ -3,7 +3,7 @@
  */
 
 /*
- * Copyright (C) 2012, 2013, 2014, 2015 Eric Biggers
+ * Copyright (C) 2012-2016 Eric Biggers
  *
  * This file is free software; you can redistribute it and/or modify it under
  * the terms of the GNU Lesser General Public License as published by the Free
@@ -46,8 +46,9 @@
  *  - wimlib does not allow *directory* hard links, so a WIM image really does
  *    have a *tree* of dentries (and not an arbitrary graph of dentries).
  *
- *  - wimlib indexes dentries both case-insensitively and case-sensitively,
- *    allowing either behavior to be used for path lookup.
+ *  - wimlib supports both case-sensitive and case-insensitive path lookups.
+ *    The implementation uses a single in-memory index per directory, using a
+ *    collation order like that used by NTFS; see collate_dentry_names().
  *
  *  - Multiple dentries in a directory might have the same case-insensitive
  *    name.  But wimlib enforces that at most one dentry in a directory can have
@@ -92,10 +93,10 @@ struct wim_dentry_on_disk {
        le32 attributes;
 
        /* A value that specifies the security descriptor for this file or
-        * directory.  If -1, the file or directory has no security descriptor.
-        * Otherwise, it is a 0-based index into the WIM image's table of
-        * security descriptors (see: `struct wim_security_data') */
-       sle32 security_id;
+        * directory.  If 0xFFFFFFFF, the file or directory has no security
+        * descriptor.  Otherwise, it is a 0-based index into the WIM image's
+        * table of security descriptors (see: `struct wim_security_data') */
+       le32 security_id;
 
        /* Offset, in bytes, from the start of the uncompressed metadata
         * resource of this directory's child directory entries, or 0 if this
@@ -358,7 +359,8 @@ dentry_out_total_length(const struct wim_dentry *dentry)
                                        dentry->d_short_name_nbytes);
        len = ALIGN(len, 8);
 
-       len += ALIGN(inode->i_extra_size, 8);
+       if (inode->i_extra)
+               len += ALIGN(inode->i_extra->size, 8);
 
        if (!(inode->i_attributes & FILE_ATTRIBUTE_ENCRYPTED)) {
                /*
@@ -435,9 +437,8 @@ do_for_dentry_in_tree_depth(struct wim_dentry *dentry,
  * @arg will be passed as the second argument to each invocation of @visitor.
  *
  * This function does a pre-order traversal --- that is, a parent will be
- * visited before its children.  It also will visit siblings in order of
- * case-sensitive filename.  Equivalently, this function visits the entire tree
- * in the case-sensitive lexicographic order of the full paths.
+ * visited before its children.  Furthermore, siblings will be visited in their
+ * collation order.
  *
  * It is safe to pass NULL for @root, which means that the dentry tree is empty.
  * In this case, this function does nothing.
@@ -483,7 +484,6 @@ int
 calculate_dentry_full_path(struct wim_dentry *dentry)
 {
        size_t ulen;
-       size_t dummy;
        const struct wim_dentry *d;
 
        if (dentry->d_full_path)
@@ -503,7 +503,8 @@ calculate_dentry_full_path(struct wim_dentry *dentry)
        d = dentry;
        do {
                p -= d->d_name_nbytes / sizeof(utf16lechar);
-               memcpy(p, d->d_name, d->d_name_nbytes);
+               if (d->d_name_nbytes)
+                       memcpy(p, d->d_name, d->d_name_nbytes);
                *--p = cpu_to_le16(WIM_PATH_SEPARATOR);
                d = d->d_parent;  /* assumes d == d->d_parent for root  */
        } while (!dentry_is_root(d));
@@ -511,7 +512,7 @@ calculate_dentry_full_path(struct wim_dentry *dentry)
        wimlib_assert(p == ubuf);
 
        return utf16le_to_tstr(ubuf, ulen * sizeof(utf16lechar),
-                              &dentry->d_full_path, &dummy);
+                              &dentry->d_full_path, NULL);
 }
 
 /*
@@ -571,50 +572,34 @@ calculate_subdir_offsets(struct wim_dentry *root, u64 *subdir_offset_p)
        for_dentry_in_tree(root, dentry_calculate_subdir_offset, subdir_offset_p);
 }
 
-/* Compare the UTF-16LE long filenames of two dentries case insensitively.  */
 static int
-dentry_compare_names_case_insensitive(const struct wim_dentry *d1,
-                                     const struct wim_dentry *d2)
+dentry_compare_names(const struct wim_dentry *d1, const struct wim_dentry *d2,
+                    bool ignore_case)
 {
-       return cmp_utf16le_strings(d1->d_name,
-                                  d1->d_name_nbytes / 2,
-                                  d2->d_name,
-                                  d2->d_name_nbytes / 2,
-                                  true);
-}
-
-/* Compare the UTF-16LE long filenames of two dentries case sensitively.  */
-static int
-dentry_compare_names_case_sensitive(const struct wim_dentry *d1,
-                                   const struct wim_dentry *d2)
-{
-       return cmp_utf16le_strings(d1->d_name,
-                                  d1->d_name_nbytes / 2,
-                                  d2->d_name,
-                                  d2->d_name_nbytes / 2,
-                                  false);
-}
-
-static int
-_avl_dentry_compare_names_ci(const struct avl_tree_node *n1,
-                            const struct avl_tree_node *n2)
-{
-       const struct wim_dentry *d1, *d2;
-
-       d1 = avl_tree_entry(n1, struct wim_dentry, d_index_node_ci);
-       d2 = avl_tree_entry(n2, struct wim_dentry, d_index_node_ci);
-       return dentry_compare_names_case_insensitive(d1, d2);
+       return cmp_utf16le_strings(d1->d_name, d1->d_name_nbytes / 2,
+                                  d2->d_name, d2->d_name_nbytes / 2,
+                                  ignore_case);
 }
 
+/*
+ * Collate (compare) the long filenames of two dentries.  This first compares
+ * the names ignoring case, then falls back to a case-sensitive comparison if
+ * the names are the same ignoring case.
+ */
 static int
-_avl_dentry_compare_names(const struct avl_tree_node *n1,
-                         const struct avl_tree_node *n2)
+collate_dentry_names(const struct avl_tree_node *n1,
+                    const struct avl_tree_node *n2)
 {
        const struct wim_dentry *d1, *d2;
+       int res;
 
        d1 = avl_tree_entry(n1, struct wim_dentry, d_index_node);
        d2 = avl_tree_entry(n2, struct wim_dentry, d_index_node);
-       return dentry_compare_names_case_sensitive(d1, d2);
+
+       res = dentry_compare_names(d1, d2, true);
+       if (res)
+               return res;
+       return dentry_compare_names(d1, d2, false);
 }
 
 /* Default case sensitivity behavior for searches with
@@ -629,99 +614,85 @@ bool default_ignore_case =
 #endif
 ;
 
-/* Case-sensitive dentry lookup.  Only @d_name and @d_name_nbytes of @dummy must
- * be valid.  */
-static struct wim_dentry *
-dir_lookup(const struct wim_inode *dir, const struct wim_dentry *dummy)
-{
-       struct avl_tree_node *node;
-
-       node = avl_tree_lookup_node(dir->i_children,
-                                   &dummy->d_index_node,
-                                   _avl_dentry_compare_names);
-       if (!node)
-               return NULL;
-       return avl_tree_entry(node, struct wim_dentry, d_index_node);
-}
-
-/* Case-insensitive dentry lookup.  Only @d_name and @d_name_nbytes of @dummy
- * must be valid.  */
-static struct wim_dentry *
-dir_lookup_ci(const struct wim_inode *dir, const struct wim_dentry *dummy)
-{
-       struct avl_tree_node *node;
-
-       node = avl_tree_lookup_node(dir->i_children_ci,
-                                   &dummy->d_index_node_ci,
-                                   _avl_dentry_compare_names_ci);
-       if (!node)
-               return NULL;
-       return avl_tree_entry(node, struct wim_dentry, d_index_node_ci);
-}
-
-/* Given a UTF-16LE filename and a directory, look up the dentry for the file.
- * Return it if found, otherwise NULL.  This has configurable case sensitivity,
- * and @name need not be null-terminated.  */
+/*
+ * Find the dentry within the given directory that has the given UTF-16LE
+ * filename.  Return it if found, otherwise return NULL.  This has configurable
+ * case sensitivity, and @name need not be null-terminated.
+ */
 struct wim_dentry *
-get_dentry_child_with_utf16le_name(const struct wim_dentry *dentry,
+get_dentry_child_with_utf16le_name(const struct wim_dentry *dir,
                                   const utf16lechar *name,
                                   size_t name_nbytes,
                                   CASE_SENSITIVITY_TYPE case_type)
 {
-       const struct wim_inode *dir = dentry->d_inode;
-       bool ignore_case = will_ignore_case(case_type);
-       struct wim_dentry dummy;
-       struct wim_dentry *child;
+       struct wim_dentry wanted;
+       struct avl_tree_node *cur = dir->d_inode->i_children;
+       struct wim_dentry *ci_match = NULL;
+
+       wanted.d_name = (utf16lechar *)name;
+       wanted.d_name_nbytes = name_nbytes;
 
-       dummy.d_name = (utf16lechar*)name;
-       dummy.d_name_nbytes = name_nbytes;
+       if (unlikely(wanted.d_name_nbytes != name_nbytes))
+               return NULL; /* overflow */
 
-       if (!ignore_case)
-               /* Case-sensitive lookup.  */
-               return dir_lookup(dir, &dummy);
+       /* Note: we can't use avl_tree_lookup_node() here because we need to
+        * save case-insensitive matches. */
+       while (cur) {
+               struct wim_dentry *child;
+               int res;
+
+               child = avl_tree_entry(cur, struct wim_dentry, d_index_node);
+
+               res = dentry_compare_names(&wanted, child, true);
+               if (!res) {
+                       /* case-insensitive match found */
+                       ci_match = child;
+
+                       res = dentry_compare_names(&wanted, child, false);
+                       if (!res)
+                               return child; /* case-sensitive match found */
+               }
+
+               if (res < 0)
+                       cur = cur->left;
+               else
+                       cur = cur->right;
+       }
 
-       /* Case-insensitive lookup.  */
+       /* No case-sensitive match; use a case-insensitive match if possible. */
 
-       child = dir_lookup_ci(dir, &dummy);
-       if (!child)
+       if (!will_ignore_case(case_type))
                return NULL;
 
-       if (likely(list_empty(&child->d_ci_conflict_list)))
-               /* Only one dentry has this case-insensitive name; return it */
-               return child;
+       if (ci_match) {
+               size_t num_other_ci_matches = 0;
+               struct wim_dentry *other_ci_match, *d;
 
-       /* Multiple dentries have the same case-insensitive name.  Choose the
-        * dentry with the same case-sensitive name, if one exists; otherwise
-        * print a warning and choose one of the possible dentries arbitrarily.
-        */
-       struct wim_dentry *alt = child;
-       size_t num_alts = 0;
+               dentry_for_each_ci_match(d, ci_match) {
+                       num_other_ci_matches++;
+                       other_ci_match = d;
+               }
 
-       do {
-               num_alts++;
-               if (!dentry_compare_names_case_sensitive(&dummy, alt))
-                       return alt;
-               alt = list_entry(alt->d_ci_conflict_list.next,
-                                struct wim_dentry, d_ci_conflict_list);
-       } while (alt != child);
-
-       WARNING("Result of case-insensitive lookup is ambiguous\n"
-               "          (returning \"%"TS"\" of %zu "
-               "possible files, including \"%"TS"\")",
-               dentry_full_path(child),
-               num_alts,
-               dentry_full_path(list_entry(child->d_ci_conflict_list.next,
-                                           struct wim_dentry,
-                                           d_ci_conflict_list)));
-       return child;
+               if (num_other_ci_matches != 0) {
+                       WARNING("Result of case-insensitive lookup is ambiguous\n"
+                               "          (returning \"%"TS"\" of %zu "
+                               "possible files, including \"%"TS"\")",
+                               dentry_full_path(ci_match), num_other_ci_matches,
+                               dentry_full_path(other_ci_match));
+               }
+       }
+
+       return ci_match;
 }
 
-/* Given a 'tchar' filename and a directory, look up the dentry for the file.
- * If the filename was successfully converted to UTF-16LE and the dentry was
- * found, return it; otherwise return NULL.  This has configurable case
- * sensitivity.  */
+/*
+ * Find the dentry within the given directory that has the given 'tstr'
+ * filename.  If the filename was successfully converted to UTF-16LE and the
+ * dentry was found, return it; otherwise return NULL.  This has configurable
+ * case sensitivity.
+ */
 struct wim_dentry *
-get_dentry_child_with_name(const struct wim_dentry *dentry, const tchar *name,
+get_dentry_child_with_name(const struct wim_dentry *dir, const tchar *name,
                           CASE_SENSITIVITY_TYPE case_type)
 {
        int ret;
@@ -734,7 +705,7 @@ get_dentry_child_with_name(const struct wim_dentry *dentry, const tchar *name,
        if (ret)
                return NULL;
 
-       child = get_dentry_child_with_utf16le_name(dentry,
+       child = get_dentry_child_with_utf16le_name(dir,
                                                   name_utf16le,
                                                   name_utf16le_nbytes,
                                                   case_type);
@@ -1046,134 +1017,99 @@ free_dentry_tree(struct wim_dentry *root, struct blob_table *blob_table)
        for_dentry_in_tree_depth(root, f, blob_table);
 }
 
-/* Insert the @child dentry into the case sensitive index of the @dir directory.
- * Return NULL if successfully inserted, otherwise a pointer to the
- * already-inserted duplicate.  */
-static struct wim_dentry *
-dir_index_child(struct wim_inode *dir, struct wim_dentry *child)
+/*
+ * Return the first dentry in the list of dentries which have the same
+ * case-insensitive name as the one given.
+ */
+struct wim_dentry *
+dentry_get_first_ci_match(struct wim_dentry *dentry)
 {
-       struct avl_tree_node *duplicate;
+       struct wim_dentry *ci_match = dentry;
 
-       duplicate = avl_tree_insert(&dir->i_children,
-                                   &child->d_index_node,
-                                   _avl_dentry_compare_names);
-       if (!duplicate)
-               return NULL;
-       return avl_tree_entry(duplicate, struct wim_dentry, d_index_node);
-}
+       for (;;) {
+               struct avl_tree_node *node;
+               struct wim_dentry *prev;
+
+               node = avl_tree_prev_in_order(&ci_match->d_index_node);
+               if (!node)
+                       break;
+               prev = avl_tree_entry(node, struct wim_dentry, d_index_node);
+               if (dentry_compare_names(prev, dentry, true))
+                       break;
+               ci_match = prev;
+       }
 
-/* Insert the @child dentry into the case insensitive index of the @dir
- * directory.  Return NULL if successfully inserted, otherwise a pointer to the
- * already-inserted duplicate.  */
-static struct wim_dentry *
-dir_index_child_ci(struct wim_inode *dir, struct wim_dentry *child)
-{
-       struct avl_tree_node *duplicate;
+       if (ci_match == dentry)
+               return dentry_get_next_ci_match(dentry, dentry);
 
-       duplicate = avl_tree_insert(&dir->i_children_ci,
-                                   &child->d_index_node_ci,
-                                   _avl_dentry_compare_names_ci);
-       if (!duplicate)
-               return NULL;
-       return avl_tree_entry(duplicate, struct wim_dentry, d_index_node_ci);
+       return ci_match;
 }
 
-/* Remove the specified dentry from its directory's case-sensitive index.  */
-static void
-dir_unindex_child(struct wim_inode *dir, struct wim_dentry *child)
+/*
+ * Return the next dentry in the list of dentries which have the same
+ * case-insensitive name as the one given.
+ */
+struct wim_dentry *
+dentry_get_next_ci_match(struct wim_dentry *dentry, struct wim_dentry *ci_match)
 {
-       avl_tree_remove(&dir->i_children, &child->d_index_node);
-}
+       do {
+               struct avl_tree_node *node;
 
-/* Remove the specified dentry from its directory's case-insensitive index.  */
-static void
-dir_unindex_child_ci(struct wim_inode *dir, struct wim_dentry *child)
-{
-       avl_tree_remove(&dir->i_children_ci, &child->d_index_node_ci);
-}
+               node = avl_tree_next_in_order(&ci_match->d_index_node);
+               if (!node)
+                       return NULL;
+               ci_match = avl_tree_entry(node, struct wim_dentry, d_index_node);
+       } while (ci_match == dentry);
 
-/* Return true iff the specified dentry is in its parent directory's
- * case-insensitive index.  */
-static bool
-dentry_in_ci_index(const struct wim_dentry *dentry)
-{
-       return !avl_tree_node_is_unlinked(&dentry->d_index_node_ci);
+       if (dentry_compare_names(ci_match, dentry, true))
+               return NULL;
+
+       return ci_match;
 }
 
 /*
- * Link a dentry into the tree.
+ * Link a dentry into a directory.
  *
  * @parent:
- *     The dentry that will be the parent of @child.  It must name a directory.
+ *     The directory into which to link the dentry.
  *
  * @child:
- *     The dentry to link.  It must be currently unlinked.
+ *     The dentry to link into the directory.  It must be currently unlinked.
  *
- * Returns NULL if successful.  If @parent already contains a dentry with the
- * same case-sensitive name as @child, returns a pointer to this duplicate
- * dentry.
+ * Returns NULL if successful; or, if @parent already contains a dentry with the
+ * same case-sensitive name as @child, then a pointer to this duplicate dentry
+ * is returned.
  */
 struct wim_dentry *
 dentry_add_child(struct wim_dentry *parent, struct wim_dentry *child)
 {
-       struct wim_dentry *duplicate;
-       struct wim_inode *dir;
+       struct wim_inode *dir = parent->d_inode;
+       struct avl_tree_node *duplicate;
 
        wimlib_assert(parent != child);
-
-       dir = parent->d_inode;
-
        wimlib_assert(inode_is_directory(dir));
 
-       duplicate = dir_index_child(dir, child);
+       duplicate = avl_tree_insert(&dir->i_children, &child->d_index_node,
+                                   collate_dentry_names);
        if (duplicate)
-               return duplicate;
+               return avl_tree_entry(duplicate, struct wim_dentry, d_index_node);
 
-       duplicate = dir_index_child_ci(dir, child);
-       if (duplicate) {
-               list_add(&child->d_ci_conflict_list, &duplicate->d_ci_conflict_list);
-               avl_tree_node_set_unlinked(&child->d_index_node_ci);
-       } else {
-               INIT_LIST_HEAD(&child->d_ci_conflict_list);
-       }
        child->d_parent = parent;
        return NULL;
 }
 
-/* Unlink a dentry from the tree.  */
+/* Unlink a dentry from its parent directory. */
 void
 unlink_dentry(struct wim_dentry *dentry)
 {
-       struct wim_inode *dir;
-
        /* Do nothing if the dentry is root or it's already unlinked.  Not
         * actually necessary based on the current callers, but we do the check
         * here to be safe.  */
        if (unlikely(dentry->d_parent == dentry))
                return;
 
-       dir = dentry->d_parent->d_inode;
-
-       dir_unindex_child(dir, dentry);
-
-       if (dentry_in_ci_index(dentry)) {
-
-               dir_unindex_child_ci(dir, dentry);
-
-               if (!list_empty(&dentry->d_ci_conflict_list)) {
-                       /* Make a different case-insensitively-the-same dentry
-                        * be the "representative" in the search index.  */
-                       struct list_head *next;
-                       struct wim_dentry *other;
-                       struct wim_dentry *existing;
-
-                       next = dentry->d_ci_conflict_list.next;
-                       other = list_entry(next, struct wim_dentry, d_ci_conflict_list);
-                       existing = dir_index_child_ci(dir, other);
-                       wimlib_assert(existing == NULL);
-               }
-       }
-       list_del(&dentry->d_ci_conflict_list);
+       avl_tree_remove(&dentry->d_parent->d_inode->i_children,
+                       &dentry->d_index_node);
 
        /* Not actually necessary, but to be safe don't retain the now-obsolete
         * parent pointer.  */
@@ -1187,10 +1123,12 @@ read_extra_data(const u8 *p, const u8 *end, struct wim_inode *inode)
                p++;
 
        if (unlikely(p < end)) {
-               inode->i_extra = memdup(p, end - p);
+               inode->i_extra = MALLOC(sizeof(struct wim_inode_extra) +
+                                       end - p);
                if (!inode->i_extra)
                        return WIMLIB_ERR_NOMEM;
-               inode->i_extra_size = end - p;
+               inode->i_extra->size = end - p;
+               memcpy(inode->i_extra->data, p, end - p);
        }
        return 0;
 }
@@ -1227,6 +1165,12 @@ assign_stream_types_encrypted(struct wim_inode *inode)
  * There will be an unnamed data stream, a reparse point stream, or both an
  * unnamed data stream and a reparse point stream.  In addition, there may be
  * named data streams.
+ *
+ * NOTE: if the file has a reparse point stream or at least one named data
+ * stream, then WIMGAPI puts *all* streams in the extra stream entries and
+ * leaves the default stream hash zeroed.  wimlib now does the same.  However,
+ * for input we still support the default hash field being used, since wimlib
+ * used to use it and MS software is somewhat accepting of it as well.
  */
 static void
 assign_stream_types_unencrypted(struct wim_inode *inode)
@@ -1241,7 +1185,10 @@ assign_stream_types_unencrypted(struct wim_inode *inode)
                if (stream_is_named(strm)) {
                        /* Named data stream  */
                        strm->stream_type = STREAM_TYPE_DATA;
-               } else if (!is_zero_hash(strm->_stream_hash)) {
+               } else if (i != 0 || !is_zero_hash(strm->_stream_hash)) {
+                       /* Unnamed stream in the extra stream entries, OR the
+                        * default stream in the dentry provided that it has a
+                        * nonzero hash.  */
                        if ((inode->i_attributes & FILE_ATTRIBUTE_REPARSE_POINT) &&
                            !found_reparse_point_stream) {
                                found_reparse_point_stream = true;
@@ -1250,17 +1197,21 @@ assign_stream_types_unencrypted(struct wim_inode *inode)
                                found_unnamed_data_stream = true;
                                strm->stream_type = STREAM_TYPE_DATA;
                        }
-               } else {
-                       /* If no stream name is specified and the hash is zero,
-                        * then remember this stream for later so that we can
-                        * assign it to the unnamed data stream if we don't find
-                        * a better candidate.  */
+               } else if (!unnamed_stream_with_zero_hash) {
                        unnamed_stream_with_zero_hash = strm;
                }
        }
 
-       if (!found_unnamed_data_stream && unnamed_stream_with_zero_hash != NULL)
-               unnamed_stream_with_zero_hash->stream_type = STREAM_TYPE_DATA;
+       if (unnamed_stream_with_zero_hash) {
+               int type = STREAM_TYPE_UNKNOWN;
+               if ((inode->i_attributes & FILE_ATTRIBUTE_REPARSE_POINT) &&
+                   !found_reparse_point_stream) {
+                       type = STREAM_TYPE_REPARSE_POINT;
+               } else if (!found_unnamed_data_stream) {
+                       type = STREAM_TYPE_DATA;
+               }
+               unnamed_stream_with_zero_hash->stream_type = type;
+       }
 }
 
 /*
@@ -1381,7 +1332,7 @@ read_dentry(const u8 * restrict buf, size_t buf_len,
        u64 calculated_size;
        int ret;
 
-       BUILD_BUG_ON(sizeof(struct wim_dentry_on_disk) != WIM_DENTRY_DISK_SIZE);
+       STATIC_ASSERT(sizeof(struct wim_dentry_on_disk) == WIM_DENTRY_DISK_SIZE);
 
        /* Before reading the whole dentry, we need to read just the length.
         * This is because a dentry of length 8 (that is, just the length field)
@@ -1515,7 +1466,6 @@ err_free_dentry:
        return ret;
 }
 
-/* Is the dentry named "." or ".." ?  */
 static bool
 dentry_is_dot_or_dotdot(const struct wim_dentry *dentry)
 {
@@ -1532,23 +1482,56 @@ dentry_is_dot_or_dotdot(const struct wim_dentry *dentry)
        return false;
 }
 
+static bool
+dentry_contains_embedded_null(const struct wim_dentry *dentry)
+{
+       for (unsigned i = 0; i < dentry->d_name_nbytes / 2; i++)
+               if (dentry->d_name[i] == cpu_to_le16('\0'))
+                       return true;
+       return false;
+}
+
+static bool
+should_ignore_dentry(struct wim_dentry *dir, const struct wim_dentry *dentry)
+{
+       /* All dentries except the root must be named. */
+       if (!dentry_has_long_name(dentry)) {
+               WARNING("Ignoring unnamed file in directory \"%"TS"\"",
+                       dentry_full_path(dir));
+               return true;
+       }
+
+       /* Don't allow files named "." or "..".  Such filenames could be used in
+        * path traversal attacks. */
+       if (dentry_is_dot_or_dotdot(dentry)) {
+               WARNING("Ignoring file named \".\" or \"..\" in directory "
+                       "\"%"TS"\"", dentry_full_path(dir));
+               return true;
+       }
+
+       /* Don't allow filenames containing embedded null characters.  Although
+        * the null character is already considered an unsupported character for
+        * extraction by all targets, it is probably a good idea to just forbid
+        * such names entirely. */
+       if (dentry_contains_embedded_null(dentry)) {
+               WARNING("Ignoring filename with embedded null character in "
+                       "directory \"%"TS"\"", dentry_full_path(dir));
+               return true;
+       }
+
+       return false;
+}
+
 static int
 read_dentry_tree_recursive(const u8 * restrict buf, size_t buf_len,
-                          struct wim_dentry * restrict dir)
+                          struct wim_dentry * restrict dir, unsigned depth)
 {
        u64 cur_offset = dir->d_subdir_offset;
 
-       /* Check for cyclic directory structure, which would cause infinite
-        * recursion if not handled.  */
-       for (struct wim_dentry *d = dir->d_parent;
-            !dentry_is_root(d); d = d->d_parent)
-       {
-               if (unlikely(d->d_subdir_offset == cur_offset)) {
-                       ERROR("Cyclic directory structure detected: children "
-                             "of \"%"TS"\" coincide with children of \"%"TS"\"",
-                             dentry_full_path(dir), dentry_full_path(d));
-                       return WIMLIB_ERR_INVALID_METADATA_RESOURCE;
-               }
+       /* Disallow extremely deep or cyclic directory structures  */
+       if (unlikely(depth >= 16384)) {
+               ERROR("Directory structure too deep!");
+               return WIMLIB_ERR_INVALID_METADATA_RESOURCE;
        }
 
        for (;;) {
@@ -1565,18 +1548,8 @@ read_dentry_tree_recursive(const u8 * restrict buf, size_t buf_len,
                if (child == NULL)
                        return 0;
 
-               /* All dentries except the root should be named.  */
-               if (unlikely(!dentry_has_long_name(child))) {
-                       WARNING("Ignoring unnamed dentry in "
-                               "directory \"%"TS"\"", dentry_full_path(dir));
-                       free_dentry(child);
-                       continue;
-               }
-
-               /* Don't allow files named "." or "..".  */
-               if (unlikely(dentry_is_dot_or_dotdot(child))) {
-                       WARNING("Ignoring file named \".\" or \"..\"; "
-                               "potentially malicious archive!!!");
+               /* Ignore dentries with bad names.  */
+               if (unlikely(should_ignore_dentry(dir, child))) {
                        free_dentry(child);
                        continue;
                }
@@ -1601,7 +1574,8 @@ read_dentry_tree_recursive(const u8 * restrict buf, size_t buf_len,
                        if (likely(dentry_is_directory(child))) {
                                ret = read_dentry_tree_recursive(buf,
                                                                 buf_len,
-                                                                child);
+                                                                child,
+                                                                depth + 1);
                                if (ret)
                                        return ret;
                        } else {
@@ -1642,8 +1616,6 @@ read_dentry_tree(const u8 *buf, size_t buf_len,
        int ret;
        struct wim_dentry *root;
 
-       DEBUG("Reading dentry tree (root_offset=%"PRIu64")", root_offset);
-
        ret = read_dentry(buf, buf_len, &root_offset, &root);
        if (ret)
                return ret;
@@ -1664,7 +1636,7 @@ read_dentry_tree(const u8 *buf, size_t buf_len,
                }
 
                if (likely(root->d_subdir_offset != 0)) {
-                       ret = read_dentry_tree_recursive(buf, buf_len, root);
+                       ret = read_dentry_tree_recursive(buf, buf_len, root, 0);
                        if (ret)
                                goto err_free_dentry_tree;
                }
@@ -1769,9 +1741,9 @@ write_dentry(const struct wim_dentry * restrict dentry, u8 * restrict p)
        while ((uintptr_t)p & 7)
                *p++ = 0;
 
-       if (inode->i_extra_size) {
+       if (inode->i_extra) {
                /* Extra tagged items --- not usually present.  */
-               p = mempcpy(p, inode->i_extra, inode->i_extra_size);
+               p = mempcpy(p, inode->i_extra->data, inode->i_extra->size);
 
                /* Align to 8-byte boundary */
                while ((uintptr_t)p & 7)
@@ -1890,10 +1862,6 @@ write_dir_dentries(struct wim_dentry *dir, void *_pp)
 u8 *
 write_dentry_tree(struct wim_dentry *root, u8 *p)
 {
-       DEBUG("Writing dentry tree.");
-
-       wimlib_assert(root != NULL);
-
        /* write root dentry and end-of-directory entry following it */
        p = write_dentry(root, p);
        *(u64*)p = 0;