X-Git-Url: https://wimlib.net/git/?a=blobdiff_plain;f=src%2Fdentry.c;h=af27c68776459c2d1272656b42a2b4b9e84039df;hb=d4f8cc3998aebb08c6cd12d248173323b43c07b8;hp=45093069001ea6a94c7df3614690675e6e914cb0;hpb=01c6f902b2a48a33af3f94e29791f85c68df91d0;p=wimlib

diff --git a/src/dentry.c b/src/dentry.c
index 45093069..af27c687 100644
--- a/src/dentry.c
+++ b/src/dentry.c
@@ -38,6 +38,7 @@
 #include "wimlib/lookup_table.h"
 #include "wimlib/metadata.h"
 #include "wimlib/resource.h"
+#include "wimlib/security.h"
 #include "wimlib/sha1.h"
 #include "wimlib/timestamp.h"
 
@@ -72,18 +73,107 @@ struct wim_ads_entry_on_disk {
 
 #define WIM_ADS_ENTRY_DISK_SIZE 38
 
-/* WIM directory entry (on-disk format) */
+/* On-disk format of a WIM dentry (directory entry), located in the metadata
+ * resource for a WIM image.  */
 struct wim_dentry_on_disk {
+
+	/* Length of this directory entry in bytes, not including any alternate
+	 * data stream entries.  Should be a multiple of 8 so that the following
+	 * dentry or alternate data stream entry is aligned on an 8-byte
+	 * boundary.  (If not, wimlib will round it up.)  It must be at least as
+	 * long as the fixed-length fields of the dentry (WIM_DENTRY_DISK_SIZE),
+	 * plus the lengths of the file name and/or short name if present.
+	 *
+	 * It is also possible for this field to be 0.  This situation, which is
+	 * undocumented, indicates the end of a list of sibling nodes in a
+	 * directory.  It also means the real length is 8, because the dentry
+	 * included only the length field, but that takes up 8 bytes.  */
 	le64 length;
+
+	/* Attributes of the file or directory.  This is a bitwise OR of the
+	 * FILE_ATTRIBUTE_* constants and should correspond to the value
+	 * retrieved by GetFileAttributes() on Windows. */
 	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;
+
+	/* Offset, in bytes, from the start of the uncompressed metadata
+	 * resource of this directory's child directory entries, or 0 if this
+	 * directory entry does not correspond to a directory or otherwise does
+	 * not have any children. */
 	le64 subdir_offset;
+
+	/* Reserved fields */
 	le64 unused_1;
 	le64 unused_2;
+
+
+	/* Creation time, last access time, and last write time, in
+	 * 100-nanosecond intervals since 12:00 a.m UTC January 1, 1601.  They
+	 * should correspond to the times gotten by calling GetFileTime() on
+	 * Windows. */
 	le64 creation_time;
 	le64 last_access_time;
 	le64 last_write_time;
+
+	/* Vaguely, the SHA-1 message digest ("hash") of the file's contents.
+	 * More specifically, this is for the "unnamed data stream" rather than
+	 * any "alternate data streams".  This hash value is used to look up the
+	 * corresponding entry in the WIM's stream lookup table to actually find
+	 * the file contents within the WIM.
+	 *
+	 * If the file has no unnamed data stream (e.g. is a directory), then
+	 * this field will be all zeroes.  If the unnamed data stream is empty
+	 * (i.e. an "empty file"), then this field is also expected to be all
+	 * zeroes.  (It will be if wimlib created the WIM image, at least;
+	 * otherwise it can't be ruled out that the SHA-1 message digest of 0
+	 * bytes of data is given explicitly.)
+	 *
+	 * If the file has reparse data, then this field will instead specify
+	 * the SHA-1 message digest of the reparse data.  If it is somehow
+	 * possible for a file to have both an unnamed data stream and reparse
+	 * data, then this is not handled by wimlib.
+	 *
+	 * As a further special case, if this field is all zeroes but there is
+	 * an alternate data stream entry with no name and a nonzero SHA-1
+	 * message digest field, then that hash must be used instead of this
+	 * one.  (wimlib does not use this quirk on WIM images it creates.)
+	 */
 	u8 unnamed_stream_hash[SHA1_HASH_SIZE];
+
+	/* The format of the following data is not yet completely known and they
+	 * do not correspond to Microsoft's documentation.
+	 *
+	 * If this directory entry is for a reparse point (has
+	 * FILE_ATTRIBUTE_REPARSE_POINT set in the attributes field), then the
+	 * version of the following fields containing the reparse tag is valid.
+	 * Furthermore, the field notated as not_rpfixed, as far as I can tell,
+	 * is supposed to be set to 1 if reparse point fixups (a.k.a. fixing the
+	 * targets of absolute symbolic links) were *not* done, and otherwise 0.
+	 *
+	 * If this directory entry is not for a reparse point, then the version
+	 * of the following fields containing the hard_link_group_id is valid.
+	 * All MS says about this field is that "If this file is part of a hard
+	 * link set, all the directory entries in the set will share the same
+	 * value in this field.".  However, more specifically I have observed
+	 * the following:
+	 *    - If the file is part of a hard link set of size 1, then the
+	 *    hard_link_group_id should be set to either 0, which is treated
+	 *    specially as indicating "not hardlinked", or any unique value.
+	 *    - The specific nonzero values used to identity hard link sets do
+	 *    not matter, as long as they are unique.
+	 *    - However, due to bugs in Microsoft's software, it is actually NOT
+	 *    guaranteed that directory entries that share the same hard link
+	 *    group ID are actually hard linked to each either.  We have to
+	 *    handle this by using special code to use distinguishing features
+	 *    (which is possible because some information about the underlying
+	 *    inode is repeated in each dentry) to split up these fake hard link
+	 *    groups into what they actually are supposed to be.
+	 */
 	union {
 		struct {
 			le32 rp_unknown_1;
@@ -96,14 +186,28 @@ struct wim_dentry_on_disk {
 			le64 hard_link_group_id;
 		} _packed_attribute nonreparse;
 	};
+
+	/* Number of alternate data stream entries that directly follow this
+	 * dentry on-disk. */
 	le16 num_alternate_data_streams;
+
+	/* Length of this file's UTF-16LE encoded short name (8.3 DOS-compatible
+	 * name), if present, in bytes, excluding the null terminator.  If this
+	 * file has no short name, then this field should be 0.  */
 	le16 short_name_nbytes;
+
+	/* Length of this file's UTF-16LE encoded "long" name, excluding the
+	 * null terminator.  If this file has no short name, then this field
+	 * should be 0.  It's expected that only the root dentry has this field
+	 * set to 0.  */
 	le16 file_name_nbytes;
 
-	/* Follewed by variable length file name, if file_name_nbytes != 0 */
-	utf16lechar file_name[];
+	/* Followed by variable length file name, in UTF16-LE, if
+	 * file_name_nbytes != 0.  Includes null terminator. */
+	/*utf16lechar file_name[];*/
 
-	/* Followed by variable length short name, if short_name_nbytes != 0 */
+	/* Followed by variable length short name, in UTF16-LE, if
+	 * short_name_nbytes != 0.  Includes null terminator. */
 	/*utf16lechar short_name[];*/
 } _packed_attribute;
 
@@ -687,8 +791,12 @@ get_dentry_utf16le(WIMStruct *wim, const utf16lechar *path)
 	return cur_dentry;
 }
 
-/* Returns the dentry corresponding to the @path, or NULL if there is no such
- * dentry. */
+/*
+ * Returns the dentry in the currently selected WIM image named by @path
+ * starting from the root of the WIM image, or NULL if there is no such dentry.
+ *
+ * On Windows, the search is done case-insensitively.
+ */
 struct wim_dentry *
 get_dentry(WIMStruct *wim, const tchar *path)
 {
@@ -880,13 +988,6 @@ new_timeless_inode(void)
 		inode->i_next_stream_id = 1;
 		inode->i_not_rpfixed = 1;
 		INIT_LIST_HEAD(&inode->i_list);
-	#ifdef WITH_FUSE
-		if (pthread_mutex_init(&inode->i_mutex, NULL) != 0) {
-			ERROR_WITH_ERRNO("Error initializing mutex");
-			FREE(inode);
-			return NULL;
-		}
-	#endif
 		INIT_LIST_HEAD(&inode->i_dentry);
 	}
 	return inode;
@@ -985,6 +1086,19 @@ new_filler_directory(const tchar *name, struct wim_dentry **dentry_ret)
 	return 0;
 }
 
+static int
+dentry_clear_inode_visited(struct wim_dentry *dentry, void *_ignore)
+{
+	dentry->d_inode->i_visited = 0;
+	return 0;
+}
+
+void
+dentry_tree_clear_inode_visited(struct wim_dentry *root)
+{
+	for_dentry_in_tree(root, dentry_clear_inode_visited, NULL);
+}
+
 static int
 init_ads_entry(struct wim_ads_entry *ads_entry, const void *name,
 	       size_t name_nbytes, bool is_utf16le)
@@ -1025,15 +1139,10 @@ free_inode(struct wim_inode *inode)
 				destroy_ads_entry(&inode->i_ads_entries[i]);
 			FREE(inode->i_ads_entries);
 		}
-	#ifdef WITH_FUSE
-		wimlib_assert(inode->i_num_opened_fds == 0);
-		FREE(inode->i_fds);
-		pthread_mutex_destroy(&inode->i_mutex);
-	#endif
 		/* HACK: This may instead delete the inode from i_list, but the
 		 * hlist_del() behaves the same as list_del(). */
-		hlist_del(&inode->i_hlist);
-		FREE(inode->i_extracted_file);
+		if (!hlist_unhashed(&inode->i_hlist))
+			hlist_del(&inode->i_hlist);
 		FREE(inode);
 	}
 }
@@ -1096,11 +1205,13 @@ do_free_dentry(struct wim_dentry *dentry, void *_lookup_table)
 /*
  * Unlinks and frees a dentry tree.
  *
- * @root: 		The root of the tree.
- * @lookup_table:  	The lookup table for dentries.  If non-NULL, the
- * 			reference counts in the lookup table for the lookup
- * 			table entries corresponding to the dentries will be
- * 			decremented.
+ * @root:
+ *	The root of the tree.
+ *
+ * @lookup_table:
+ *	The lookup table for dentries.  If non-NULL, the reference counts in the
+ *	lookup table for the lookup table entries corresponding to the dentries
+ *	will be decremented.
  */
 void
 free_dentry_tree(struct wim_dentry *root, struct wim_lookup_table *lookup_table)
@@ -1348,7 +1459,7 @@ add_stream_from_data_buffer(const void *buffer, size_t size,
 	struct wim_lookup_table_entry *lte, *existing_lte;
 
 	sha1_buffer(buffer, size, hash);
-	existing_lte = __lookup_resource(lookup_table, hash);
+	existing_lte = lookup_resource(lookup_table, hash);
 	if (existing_lte) {
 		wimlib_assert(wim_resource_size(existing_lte) == size);
 		lte = existing_lte;
@@ -1395,6 +1506,15 @@ inode_add_ads_with_data(struct wim_inode *inode, const tchar *name,
 	return 0;
 }
 
+bool
+inode_has_named_stream(const struct wim_inode *inode)
+{
+	for (u16 i = 0; i < inode->i_num_ads; i++)
+		if (ads_entry_is_named_stream(&inode->i_ads_entries[i]))
+			return true;
+	return false;
+}
+
 /* Set the unnamed stream of a WIM inode, given a data buffer containing the
  * stream contents. */
 int
@@ -1435,6 +1555,15 @@ inode_remove_ads(struct wim_inode *inode, u16 idx,
 	inode->i_num_ads--;
 }
 
+bool
+inode_has_unix_data(const struct wim_inode *inode)
+{
+	for (u16 i = 0; i < inode->i_num_ads; i++)
+		if (ads_entry_is_unix_data(&inode->i_ads_entries[i]))
+			return true;
+	return false;
+}
+
 #ifndef __WIN32__
 int
 inode_get_unix_data(const struct wim_inode *inode,
@@ -1510,19 +1639,24 @@ inode_set_unix_data(struct wim_inode *inode, uid_t uid, gid_t gid, mode_t mode,
 /*
  * Reads the alternate data stream entries of a WIM dentry.
  *
- * @p:	Pointer to buffer that starts with the first alternate stream entry.
+ * @p:
+ *	Pointer to buffer that starts with the first alternate stream entry.
  *
- * @inode:	Inode to load the alternate data streams into.
- * 		@inode->i_num_ads must have been set to the number of
- * 		alternate data streams that are expected.
+ * @inode:
+ *	Inode to load the alternate data streams into.  @inode->i_num_ads must
+ *	have been set to the number of alternate data streams that are expected.
  *
- * @remaining_size:	Number of bytes of data remaining in the buffer pointed
- * 			to by @p.
+ * @remaining_size:
+ *	Number of bytes of data remaining in the buffer pointed to by @p.
  *
+ * On success, inode->i_ads_entries is set to an array of `struct
+ * wim_ads_entry's of length inode->i_num_ads.  On failure, @inode is not
+ * modified.
  *
- * Return 0 on success or nonzero on failure.  On success, inode->i_ads_entries
- * is set to an array of `struct wim_ads_entry's of length inode->i_num_ads.  On
- * failure, @inode is not modified.
+ * Return values:
+ *	WIMLIB_ERR_SUCCESS (0)
+ *	WIMLIB_ERR_INVALID_METADATA_RESOURCE
+ *	WIMLIB_ERR_NOMEM
  */
 static int
 read_ads_entries(const u8 * restrict p, struct wim_inode * restrict inode,
@@ -1626,7 +1760,7 @@ out_of_memory:
 	goto out_free_ads_entries;
 out_invalid:
 	ERROR("An alternate data stream entry is invalid");
-	ret = WIMLIB_ERR_INVALID_DENTRY;
+	ret = WIMLIB_ERR_INVALID_METADATA_RESOURCE;
 out_free_ads_entries:
 	if (ads_entries) {
 		for (u16 i = 0; i < num_ads; i++)
@@ -1647,7 +1781,7 @@ out:
  * @metadata_resource_len:
  *		Length of the metadata resource buffer, in bytes.
  *
- * @offset: 	Offset of the dentry within the metadata resource.
+ * @offset:	Offset of the dentry within the metadata resource.
  *
  * @dentry:	A `struct wim_dentry' that will be filled in by this function.
  *
@@ -1657,9 +1791,10 @@ out:
  * this was a special "end of directory" dentry and not a real dentry.  If
  * nonzero, this was a real dentry.
  *
- * Possible errors include:
- * 	WIMLIB_ERR_NOMEM
- * 	WIMLIB_ERR_INVALID_DENTRY
+ * Return values:
+ *	WIMLIB_ERR_SUCCESS (0)
+ *	WIMLIB_ERR_INVALID_METADATA_RESOURCE
+ *	WIMLIB_ERR_NOMEM
  */
 int
 read_dentry(const u8 * restrict metadata_resource, u64 metadata_resource_len,
@@ -1693,7 +1828,7 @@ read_dentry(const u8 * restrict metadata_resource, u64 metadata_resource_len,
 		ERROR("Directory entry starting at %"PRIu64" ends past the "
 		      "end of the metadata resource (size %"PRIu64")",
 		      offset, metadata_resource_len);
-		return WIMLIB_ERR_INVALID_DENTRY;
+		return WIMLIB_ERR_INVALID_METADATA_RESOURCE;
 	}
 	dentry->length = le64_to_cpu(disk_dentry->length);
 
@@ -1715,7 +1850,7 @@ read_dentry(const u8 * restrict metadata_resource, u64 metadata_resource_len,
 		      "%"PRIu64" ends past the end of the metadata resource "
 		      "(size %"PRIu64")",
 		      offset, dentry->length, metadata_resource_len);
-		return WIMLIB_ERR_INVALID_DENTRY;
+		return WIMLIB_ERR_INVALID_METADATA_RESOURCE;
 	}
 
 	/* Make sure the dentry length is at least as large as the number of
@@ -1723,7 +1858,7 @@ read_dentry(const u8 * restrict metadata_resource, u64 metadata_resource_len,
 	if (dentry->length < sizeof(struct wim_dentry_on_disk)) {
 		ERROR("Directory entry has invalid length of %"PRIu64" bytes",
 		      dentry->length);
-		return WIMLIB_ERR_INVALID_DENTRY;
+		return WIMLIB_ERR_INVALID_METADATA_RESOURCE;
 	}
 
 	/* Allocate a `struct wim_inode' for this `struct wim_dentry'. */
@@ -1769,7 +1904,7 @@ read_dentry(const u8 * restrict metadata_resource, u64 metadata_resource_len,
 	if ((short_name_nbytes & 1) | (file_name_nbytes & 1))
 	{
 		ERROR("Dentry name is not valid UTF-16LE (odd number of bytes)!");
-		ret = WIMLIB_ERR_INVALID_DENTRY;
+		ret = WIMLIB_ERR_INVALID_METADATA_RESOURCE;
 		goto out_free_inode;
 	}
 
@@ -1786,7 +1921,7 @@ read_dentry(const u8 * restrict metadata_resource, u64 metadata_resource_len,
 		ERROR("Unexpected end of directory entry! (Expected "
 		      "at least %"PRIu64" bytes, got %"PRIu64" bytes.)",
 		      calculated_size, dentry->length);
-		ret = WIMLIB_ERR_INVALID_DENTRY;
+		ret = WIMLIB_ERR_INVALID_METADATA_RESOURCE;
 		goto out_free_inode;
 	}
 
@@ -1840,7 +1975,7 @@ read_dentry(const u8 * restrict metadata_resource, u64 metadata_resource_len,
 	 * be included in the dentry->length field for some reason.
 	 */
 	if (inode->i_num_ads != 0) {
-		ret = WIMLIB_ERR_INVALID_DENTRY;
+		ret = WIMLIB_ERR_INVALID_METADATA_RESOURCE;
 		if (offset + dentry->length > metadata_resource_len ||
 		    (ret = read_ads_entries(&metadata_resource[offset + dentry->length],
 					    inode,
@@ -1885,26 +2020,32 @@ dentry_get_file_type_string(const struct wim_dentry *dentry)
 /* Reads the children of a dentry, and all their children, ..., etc. from the
  * metadata resource and into the dentry tree.
  *
- * @metadata_resource:	An array that contains the uncompressed metadata
- * 			resource for the WIM file.
+ * @metadata_resource:
+ *	An array that contains the uncompressed metadata resource for the WIM
+ *	file.
  *
- * @metadata_resource_len:  The length of the uncompressed metadata resource, in
- * 			    bytes.
+ * @metadata_resource_len:
+ *	The length of the uncompressed metadata resource, in bytes.
  *
- * @dentry:	A pointer to a `struct wim_dentry' that is the root of the directory
- *		tree and has already been read from the metadata resource.  It
- *		does not need to be the real root because this procedure is
- *		called recursively.
+ * @dentry:
+ *	A pointer to a `struct wim_dentry' that is the root of the directory
+ *	tree and has already been read from the metadata resource.  It does not
+ *	need to be the real root because this procedure is called recursively.
  *
- * Returns zero on success; nonzero on failure.
+ * Return values:
+ *	WIMLIB_ERR_SUCCESS (0)
+ *	WIMLIB_ERR_INVALID_METADATA_RESOURCE
+ *	WIMLIB_ERR_NOMEM
  */
 int
-read_dentry_tree(const u8 metadata_resource[], u64 metadata_resource_len,
-		 struct wim_dentry *dentry)
+read_dentry_tree(const u8 * restrict metadata_resource,
+		 u64 metadata_resource_len,
+		 struct wim_dentry * restrict dentry)
 {
 	u64 cur_offset = dentry->subdir_offset;
 	struct wim_dentry *child;
 	struct wim_dentry *duplicate;
+	struct wim_dentry *parent;
 	struct wim_dentry cur_child;
 	int ret;
 
@@ -1917,6 +2058,18 @@ read_dentry_tree(const u8 metadata_resource[], u64 metadata_resource_len,
 	if (cur_offset == 0)
 		return 0;
 
+	/* Check for cyclic directory structure */
+	for (parent = dentry->parent; !dentry_is_root(parent); parent = parent->parent)
+	{
+		if (unlikely(parent->subdir_offset == cur_offset)) {
+			ERROR("Cyclic directory structure directed: children "
+			      "of \"%"TS"\" coincide with children of \"%"TS"\"",
+			      dentry_full_path(dentry),
+			      dentry_full_path(parent));
+			return WIMLIB_ERR_INVALID_METADATA_RESOURCE;
+		}
+	}
+
 	/* Find and read all the children of @dentry. */
 	for (;;) {
 
@@ -1946,8 +2099,16 @@ read_dentry_tree(const u8 metadata_resource[], u64 metadata_resource_len,
 		 * entries. */
 		cur_offset += dentry_total_length(child);
 
+		if (unlikely(!dentry_has_long_name(child))) {
+			WARNING("Ignoring unnamed dentry in "
+				"directory \"%"TS"\"",
+				dentry_full_path(dentry));
+			free_dentry(child);
+			continue;
+		}
+
 		duplicate = dentry_add_child(dentry, child);
-		if (duplicate) {
+		if (unlikely(duplicate)) {
 			const tchar *child_type, *duplicate_type;
 			child_type = dentry_get_file_type_string(child);
 			duplicate_type = dentry_get_file_type_string(duplicate);
@@ -1956,23 +2117,24 @@ read_dentry_tree(const u8 metadata_resource[], u64 metadata_resource_len,
 				"at that path with the exact same name)",
 				child_type, dentry_full_path(duplicate),
 				duplicate_type);
-		} else {
-			inode_add_dentry(child, child->d_inode);
-			/* If there are children of this child, call this
-			 * procedure recursively. */
-			if (child->subdir_offset != 0) {
-				if (dentry_is_directory(child)) {
-					ret = read_dentry_tree(metadata_resource,
-							       metadata_resource_len,
-							       child);
-					if (ret)
-						break;
-				} else {
-					WARNING("Ignoring children of non-directory \"%"TS"\"",
-						dentry_full_path(child));
-				}
-			}
+			free_dentry(child);
+			continue;
+		}
 
+		inode_add_dentry(child, child->d_inode);
+		/* If there are children of this child, call this
+		 * procedure recursively. */
+		if (child->subdir_offset != 0) {
+			if (likely(dentry_is_directory(child))) {
+				ret = read_dentry_tree(metadata_resource,
+						       metadata_resource_len,
+						       child);
+				if (ret)
+					break;
+			} else {
+				WARNING("Ignoring children of non-directory \"%"TS"\"",
+					dentry_full_path(child));
+			}
 		}
 	}
 	return ret;
@@ -1998,7 +2160,7 @@ write_dentry(const struct wim_dentry * restrict dentry, u8 * restrict p)
 	wimlib_assert(((uintptr_t)p & 7) == 0); /* 8 byte aligned */
 	orig_p = p;
 
- 	inode = dentry->d_inode;
+	inode = dentry->d_inode;
 	disk_dentry = (struct wim_dentry_on_disk*)p;
 
 	disk_dentry->attributes = cpu_to_le32(inode->i_attributes);
@@ -2026,6 +2188,8 @@ write_dentry(const struct wim_dentry * restrict dentry, u8 * restrict p)
 	disk_dentry->file_name_nbytes = cpu_to_le16(dentry->file_name_nbytes);
 	p += sizeof(struct wim_dentry_on_disk);
 
+	wimlib_assert(dentry_is_root(dentry) != dentry_has_long_name(dentry));
+
 	if (dentry_has_long_name(dentry))
 		p = mempcpy(p, dentry->file_name, dentry->file_name_nbytes + 2);
 
@@ -2122,7 +2286,7 @@ write_dentry_tree_recursive(const struct wim_dentry *parent, u8 *p)
  * Returns pointer to the byte after the last byte we wrote.
  */
 u8 *
-write_dentry_tree(const struct wim_dentry *root, u8 *p)
+write_dentry_tree(const struct wim_dentry * restrict root, u8 * restrict p)
 {
 	DEBUG("Writing dentry tree.");
 	wimlib_assert(dentry_is_root(root));
@@ -2139,3 +2303,422 @@ write_dentry_tree(const struct wim_dentry *root, u8 *p)
 	/* Recursively write the rest of the dentry tree. */
 	return write_dentry_tree_recursive(root, p);
 }
+
+
+static int
+init_wimlib_dentry(struct wimlib_dir_entry *wdentry,
+		   struct wim_dentry *dentry,
+		   const WIMStruct *wim,
+		   int flags)
+{
+	int ret;
+	size_t dummy;
+	const struct wim_inode *inode = dentry->d_inode;
+	struct wim_lookup_table_entry *lte;
+	const u8 *hash;
+
+#if TCHAR_IS_UTF16LE
+	wdentry->filename = dentry->file_name;
+	wdentry->dos_name = dentry->short_name;
+#else
+	if (dentry_has_long_name(dentry)) {
+		ret = utf16le_to_tstr(dentry->file_name,
+				      dentry->file_name_nbytes,
+				      (tchar**)&wdentry->filename,
+				      &dummy);
+		if (ret)
+			return ret;
+	}
+	if (dentry_has_short_name(dentry)) {
+		ret = utf16le_to_tstr(dentry->short_name,
+				      dentry->short_name_nbytes,
+				      (tchar**)&wdentry->dos_name,
+				      &dummy);
+		if (ret)
+			return ret;
+	}
+#endif
+	ret = calculate_dentry_full_path(dentry);
+	if (ret)
+		return ret;
+	wdentry->full_path = dentry->_full_path;
+
+	for (struct wim_dentry *d = dentry; !dentry_is_root(d); d = d->parent)
+		wdentry->depth++;
+
+	if (inode->i_security_id >= 0) {
+		const struct wim_security_data *sd = wim_const_security_data(wim);
+		wdentry->security_descriptor = sd->descriptors[inode->i_security_id];
+		wdentry->security_descriptor_size = sd->sizes[inode->i_security_id];
+	}
+	wdentry->reparse_tag = inode->i_reparse_tag;
+	wdentry->num_links = inode->i_nlink;
+	wdentry->attributes = inode->i_attributes;
+	wdentry->hard_link_group_id = inode->i_ino;
+	wdentry->creation_time = wim_timestamp_to_timespec(inode->i_creation_time);
+	wdentry->last_write_time = wim_timestamp_to_timespec(inode->i_last_write_time);
+	wdentry->last_access_time = wim_timestamp_to_timespec(inode->i_last_access_time);
+
+	lte = inode_unnamed_lte(inode, wim->lookup_table);
+	if (lte) {
+		lte_to_wimlib_resource_entry(lte, &wdentry->streams[0].resource);
+	} else if (!is_zero_hash(hash = inode_unnamed_stream_hash(inode))) {
+		if (flags & WIMLIB_ITERATE_DIR_TREE_FLAG_RESOURCES_NEEDED)
+			return resource_not_found_error(inode, hash);
+		copy_hash(wdentry->streams[0].resource.sha1_hash, hash);
+		wdentry->streams[0].resource.is_missing = 1;
+	}
+
+	for (unsigned i = 0; i < inode->i_num_ads; i++) {
+		if (!ads_entry_is_named_stream(&inode->i_ads_entries[i]))
+			continue;
+		lte = inode_stream_lte(inode, i + 1, wim->lookup_table);
+		wdentry->num_named_streams++;
+		if (lte) {
+			lte_to_wimlib_resource_entry(lte, &wdentry->streams[
+								wdentry->num_named_streams].resource);
+		} else if (!is_zero_hash(hash = inode_stream_hash(inode, i + 1))) {
+			if (flags & WIMLIB_ITERATE_DIR_TREE_FLAG_RESOURCES_NEEDED)
+				return resource_not_found_error(inode, hash);
+			copy_hash(wdentry->streams[
+				  wdentry->num_named_streams].resource.sha1_hash, hash);
+			wdentry->streams[
+				wdentry->num_named_streams].resource.is_missing = 1;
+		}
+	#if TCHAR_IS_UTF16LE
+		wdentry->streams[wdentry->num_named_streams].stream_name =
+				inode->i_ads_entries[i].stream_name;
+	#else
+		size_t dummy;
+
+		ret = utf16le_to_tstr(inode->i_ads_entries[i].stream_name,
+				      inode->i_ads_entries[i].stream_name_nbytes,
+				      (tchar**)&wdentry->streams[
+						wdentry->num_named_streams].stream_name,
+				      &dummy);
+		if (ret)
+			return ret;
+	#endif
+	}
+	return 0;
+}
+
+static void
+free_wimlib_dentry(struct wimlib_dir_entry *wdentry)
+{
+#if !TCHAR_IS_UTF16LE
+	FREE((tchar*)wdentry->filename);
+	FREE((tchar*)wdentry->dos_name);
+	for (unsigned i = 1; i <= wdentry->num_named_streams; i++)
+		FREE((tchar*)wdentry->streams[i].stream_name);
+#endif
+	FREE(wdentry);
+}
+
+struct iterate_dir_tree_ctx {
+	WIMStruct *wim;
+	int flags;
+	wimlib_iterate_dir_tree_callback_t cb;
+	void *user_ctx;
+};
+
+static int
+do_iterate_dir_tree(WIMStruct *wim,
+		    struct wim_dentry *dentry, int flags,
+		    wimlib_iterate_dir_tree_callback_t cb,
+		    void *user_ctx);
+
+static int
+call_do_iterate_dir_tree(struct wim_dentry *dentry, void *_ctx)
+{
+	struct iterate_dir_tree_ctx *ctx = _ctx;
+	return do_iterate_dir_tree(ctx->wim, dentry, ctx->flags,
+				   ctx->cb, ctx->user_ctx);
+}
+
+static int
+do_iterate_dir_tree(WIMStruct *wim,
+		    struct wim_dentry *dentry, int flags,
+		    wimlib_iterate_dir_tree_callback_t cb,
+		    void *user_ctx)
+{
+	struct wimlib_dir_entry *wdentry;
+	int ret = WIMLIB_ERR_NOMEM;
+
+
+	wdentry = CALLOC(1, sizeof(struct wimlib_dir_entry) +
+				  (1 + dentry->d_inode->i_num_ads) *
+					sizeof(struct wimlib_stream_entry));
+	if (!wdentry)
+		goto out;
+
+	ret = init_wimlib_dentry(wdentry, dentry, wim, flags);
+	if (ret)
+		goto out_free_wimlib_dentry;
+
+	if (!(flags & WIMLIB_ITERATE_DIR_TREE_FLAG_CHILDREN)) {
+		ret = (*cb)(wdentry, user_ctx);
+		if (ret)
+			goto out_free_wimlib_dentry;
+	}
+
+	if (flags & (WIMLIB_ITERATE_DIR_TREE_FLAG_RECURSIVE |
+		     WIMLIB_ITERATE_DIR_TREE_FLAG_CHILDREN))
+	{
+		struct iterate_dir_tree_ctx ctx = {
+			.wim      = wim,
+			.flags    = flags &= ~WIMLIB_ITERATE_DIR_TREE_FLAG_CHILDREN,
+			.cb       = cb,
+			.user_ctx = user_ctx,
+		};
+		ret = for_dentry_child(dentry, call_do_iterate_dir_tree, &ctx);
+	}
+out_free_wimlib_dentry:
+	free_wimlib_dentry(wdentry);
+out:
+	return ret;
+}
+
+struct image_iterate_dir_tree_ctx {
+	const tchar *path;
+	int flags;
+	wimlib_iterate_dir_tree_callback_t cb;
+	void *user_ctx;
+};
+
+
+static int
+image_do_iterate_dir_tree(WIMStruct *wim)
+{
+	struct image_iterate_dir_tree_ctx *ctx = wim->private;
+	struct wim_dentry *dentry;
+
+	dentry = get_dentry(wim, ctx->path);
+	if (!dentry)
+		return WIMLIB_ERR_PATH_DOES_NOT_EXIST;
+	return do_iterate_dir_tree(wim, dentry, ctx->flags, ctx->cb, ctx->user_ctx);
+}
+
+/* API function documented in wimlib.h  */
+WIMLIBAPI int
+wimlib_iterate_dir_tree(WIMStruct *wim, int image, const tchar *path,
+			int flags,
+			wimlib_iterate_dir_tree_callback_t cb, void *user_ctx)
+{
+	struct image_iterate_dir_tree_ctx ctx = {
+		.path = path,
+		.flags = flags,
+		.cb = cb,
+		.user_ctx = user_ctx,
+	};
+	wim->private = &ctx;
+	return for_image(wim, image, image_do_iterate_dir_tree);
+}
+
+/* Returns %true iff the metadata of @inode and @template_inode are reasonably
+ * consistent with them being the same, unmodified file.  */
+static bool
+inode_metadata_consistent(const struct wim_inode *inode,
+			  const struct wim_inode *template_inode,
+			  const struct wim_lookup_table *template_lookup_table)
+{
+	/* Must have exact same creation time and last write time.  */
+	if (inode->i_creation_time != template_inode->i_creation_time ||
+	    inode->i_last_write_time != template_inode->i_last_write_time)
+		return false;
+
+	/* Last access time may have stayed the same or increased, but certainly
+	 * shouldn't have decreased.  */
+	if (inode->i_last_access_time < template_inode->i_last_access_time)
+		return false;
+
+	/* Must have same number of alternate data stream entries.  */
+	if (inode->i_num_ads != template_inode->i_num_ads)
+		return false;
+
+	/* If the stream entries for the inode are for some reason not resolved,
+	 * then the hashes are already available and the point of this function
+	 * is defeated.  */
+	if (!inode->i_resolved)
+		return false;
+
+	/* Iterate through each stream and do some more checks.  */
+	for (unsigned i = 0; i <= inode->i_num_ads; i++) {
+		const struct wim_lookup_table_entry *lte, *template_lte;
+
+		lte = inode_stream_lte_resolved(inode, i);
+		template_lte = inode_stream_lte(template_inode, i,
+						template_lookup_table);
+
+		/* Compare stream sizes.  */
+		if (lte && template_lte) {
+			if (wim_resource_size(lte) != wim_resource_size(template_lte))
+				return false;
+
+			/* If hash happens to be available, compare with template.  */
+			if (!lte->unhashed && !template_lte->unhashed &&
+			    !hashes_equal(lte->hash, template_lte->hash))
+				return false;
+
+		} else if (lte && wim_resource_size(lte)) {
+			return false;
+		} else if (template_lte && wim_resource_size(template_lte)) {
+			return false;
+		}
+	}
+
+	/* All right, barring a full checksum and given that the inodes share a
+	 * path and the user isn't trying to trick us, these inodes most likely
+	 * refer to the same file.  */
+	return true;
+}
+
+/**
+ * Given an inode @inode that has been determined to be "the same" as another
+ * inode @template_inode in either the same WIM or another WIM, retrieve some
+ * useful stream information (e.g. checksums) from @template_inode.
+ *
+ * This assumes that the streams for @inode have been resolved (to point
+ * directly to the appropriate `struct wim_lookup_table_entry's)  but do not
+ * necessarily have checksum information filled in.
+ */
+static int
+inode_copy_checksums(struct wim_inode *inode,
+		     struct wim_inode *template_inode,
+		     WIMStruct *wim,
+		     WIMStruct *template_wim)
+{
+	for (unsigned i = 0; i <= inode->i_num_ads; i++) {
+		struct wim_lookup_table_entry *lte, *template_lte;
+		struct wim_lookup_table_entry *replace_lte;
+
+		lte = inode_stream_lte_resolved(inode, i);
+		template_lte = inode_stream_lte(template_inode, i,
+						template_wim->lookup_table);
+
+		/* Only take action if both entries exist, the entry for @inode
+		 * has no checksum calculated, but the entry for @template_inode
+		 * does.  */
+		if (!lte || !template_lte ||
+		    !lte->unhashed || template_lte->unhashed)
+			continue;
+
+		wimlib_assert(lte->refcnt == inode->i_nlink);
+
+		/* If the WIM of the template image is the same as the WIM of
+		 * the new image, then @template_lte can be used directly.
+		 *
+		 * Otherwise, look for a stream with the same hash in the WIM of
+		 * the new image.  If found, use it; otherwise re-use the entry
+		 * being discarded, filling in the hash.  */
+
+		if (wim == template_wim)
+			replace_lte = template_lte;
+		else
+			replace_lte = lookup_resource(wim->lookup_table,
+						      template_lte->hash);
+
+		list_del(&lte->unhashed_list);
+		if (replace_lte) {
+			free_lookup_table_entry(lte);
+		} else {
+			copy_hash(lte->hash, template_lte->hash);
+			lte->unhashed = 0;
+			lookup_table_insert(wim->lookup_table, lte);
+			lte->refcnt = 0;
+			replace_lte = lte;
+		}
+
+		if (i == 0)
+			inode->i_lte = replace_lte;
+		else
+			inode->i_ads_entries[i - 1].lte = replace_lte;
+
+		replace_lte->refcnt += inode->i_nlink;
+	}
+	return 0;
+}
+
+struct reference_template_args {
+	WIMStruct *wim;
+	WIMStruct *template_wim;
+};
+
+static int
+dentry_reference_template(struct wim_dentry *dentry, void *_args)
+{
+	int ret;
+	struct wim_dentry *template_dentry;
+	struct wim_inode *inode, *template_inode;
+	struct reference_template_args *args = _args;
+	WIMStruct *wim = args->wim;
+	WIMStruct *template_wim = args->template_wim;
+
+	if (dentry->d_inode->i_visited)
+		return 0;
+
+	ret = calculate_dentry_full_path(dentry);
+	if (ret)
+		return ret;
+
+	template_dentry = get_dentry(template_wim, dentry->_full_path);
+	if (!template_dentry) {
+		DEBUG("\"%"TS"\": newly added file", dentry->_full_path);
+		return 0;
+	}
+
+	inode = dentry->d_inode;
+	template_inode = template_dentry->d_inode;
+
+	if (inode_metadata_consistent(inode, template_inode,
+				      template_wim->lookup_table)) {
+		/*DEBUG("\"%"TS"\": No change detected", dentry->_full_path);*/
+		ret = inode_copy_checksums(inode, template_inode,
+					   wim, template_wim);
+		inode->i_visited = 1;
+	} else {
+		DEBUG("\"%"TS"\": change detected!", dentry->_full_path);
+		ret = 0;
+	}
+	return ret;
+}
+
+/* API function documented in wimlib.h  */
+WIMLIBAPI int
+wimlib_reference_template_image(WIMStruct *wim, int new_image,
+				WIMStruct *template_wim, int template_image,
+				int flags, wimlib_progress_func_t progress_func)
+{
+	int ret;
+	struct wim_image_metadata *new_imd;
+
+	if (wim == NULL || template_wim == NULL)
+		return WIMLIB_ERR_INVALID_PARAM;
+
+	if (wim == template_wim && new_image == template_image)
+		return WIMLIB_ERR_INVALID_PARAM;
+
+	if (new_image < 1 || new_image > wim->hdr.image_count)
+		return WIMLIB_ERR_INVALID_IMAGE;
+
+	if (!wim_has_metadata(wim))
+		return WIMLIB_ERR_METADATA_NOT_FOUND;
+
+	new_imd = wim->image_metadata[new_image - 1];
+	if (!new_imd->modified)
+		return WIMLIB_ERR_INVALID_PARAM;
+
+	ret = select_wim_image(template_wim, template_image);
+	if (ret)
+		return ret;
+
+	struct reference_template_args args = {
+		.wim = wim,
+		.template_wim = template_wim,
+	};
+
+	ret = for_dentry_in_tree(new_imd->root_dentry,
+				 dentry_reference_template, &args);
+	dentry_tree_clear_inode_visited(new_imd->root_dentry);
+	return ret;
+}