6 * Copyright (C) 2012, 2013, 2014 Eric Biggers
8 * This file is free software; you can redistribute it and/or modify it under
9 * the terms of the GNU Lesser General Public License as published by the Free
10 * Software Foundation; either version 3 of the License, or (at your option) any
13 * This file is distributed in the hope that it will be useful, but WITHOUT
14 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
15 * FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
18 * You should have received a copy of the GNU Lesser General Public License
19 * along with this file; if not, see http://www.gnu.org/licenses/.
26 #include "wimlib/dentry.h"
27 #include "wimlib/error.h"
28 #include "wimlib/inode.h"
29 #include "wimlib/inode_table.h"
30 #include "wimlib/lookup_table.h"
32 struct inode_fixup_params {
33 struct wim_inode_table inode_table;
34 unsigned long num_dir_hard_links;
35 unsigned long num_inconsistent_inodes;
38 #define MAX_DIR_HARD_LINK_WARNINGS 8
41 inodes_consistent(const struct wim_inode *inode_1,
42 const struct wim_inode *inode_2)
44 /* This certainly isn't the only thing we need to check to make sure the
45 * inodes are consistent. However, this seems to be the only thing that
46 * the MS implementation checks when working around its own bug.
48 * (Tested: If two dentries share the same hard link group ID, Windows
49 * 8.1 DISM will link them if they have the same unnamed stream hash,
50 * even if the dentries provide different timestamps, attributes,
51 * alternate data streams, and security IDs! And the one that gets used
52 * will change if you merely swap the filenames. But if you use
53 * different unnamed stream hashes with everything else the same, it
54 * doesn't link the dentries.)
56 * For non-buggy WIMs this function will always return true. */
57 return hashes_equal(inode_unnamed_stream_hash(inode_1),
58 inode_unnamed_stream_hash(inode_2));
62 inode_table_insert(struct wim_dentry *dentry, void *_params)
64 struct inode_fixup_params *params = _params;
65 struct wim_inode_table *table = ¶ms->inode_table;
66 struct wim_inode *d_inode = dentry->d_inode;
68 struct wim_inode *inode;
69 struct hlist_node *cur;
71 if (d_inode->i_ino == 0) {
72 list_add_tail(&d_inode->i_list, &table->extra_inodes);
76 /* Try adding this dentry to an existing inode. */
77 pos = d_inode->i_ino % table->capacity;
78 hlist_for_each_entry(inode, cur, &table->array[pos], i_hlist) {
79 if (inode->i_ino != d_inode->i_ino) {
82 if (unlikely(!inodes_consistent(inode, d_inode))) {
83 params->num_inconsistent_inodes++;
86 if (unlikely((d_inode->i_attributes & FILE_ATTRIBUTE_DIRECTORY) ||
87 (inode->i_attributes & FILE_ATTRIBUTE_DIRECTORY)))
89 params->num_dir_hard_links++;
90 if (params->num_dir_hard_links <=
91 MAX_DIR_HARD_LINK_WARNINGS)
93 WARNING("Unsupported directory hard link "
94 "\"%"TS"\" <=> \"%"TS"\"",
95 dentry_full_path(dentry),
96 inode_first_full_path(inode));
97 } else if (params->num_dir_hard_links ==
98 MAX_DIR_HARD_LINK_WARNINGS + 1)
100 WARNING("Suppressing additional warnings about "
101 "directory hard links...");
105 /* Transfer this dentry to the existing inode. */
107 dentry->d_inode = inode;
109 inode_add_dentry(dentry, inode);
113 /* Keep this dentry's inode. */
114 hlist_add_head(&d_inode->i_hlist, &table->array[pos]);
118 /* Move the inodes from the 'struct wim_inode_table' to the 'inode_list'. */
120 build_inode_list(struct wim_inode_table *inode_table,
121 struct list_head *inode_list)
123 list_splice(&inode_table->extra_inodes, inode_list);
124 for (size_t i = 0; i < inode_table->capacity; i++) {
125 while (!hlist_empty(&inode_table->array[i])) {
126 struct wim_inode *inode;
128 inode = hlist_entry(inode_table->array[i].first,
129 struct wim_inode, i_hlist);
130 hlist_del(&inode->i_hlist);
131 list_add(&inode->i_list, inode_list);
136 /* Re-assign inode numbers to the inodes in the list. */
138 reassign_inode_numbers(struct list_head *inode_list)
140 struct wim_inode *inode;
143 list_for_each_entry(inode, inode_list, i_list)
144 inode->i_ino = cur_ino++;
148 * Given a WIM image's tree of dentries such that each dentry initially
149 * has a unique inode associated with it, determine the actual
150 * dentry/inode information. Following this, a single inode may be named
151 * by more than one dentry (usually called a hard link).
153 * The 'hard_link_group_id' field of the on-disk WIM dentry, which we
154 * have read into 'i_ino' of each dentry's initial inode, determines
155 * which dentries share the same inode. Ideally, dentries share the same
156 * inode if and only if they have the same value in this field. However,
159 * - If 'hard_link_group_id' is 0, the corresponding dentry is the sole
160 * name for its inode.
161 * - Due to bugs in the Microsoft implementation, dentries with different
162 * 'hard_link_group_id' fields may, in fact, need to be interpreted as
163 * naming different inodes. This seems to mostly affect images in
164 * install.wim for Windows 7. I try to work around this in the same way
165 * the Microsoft implementation works around this.
167 * Returns 0 or WIMLIB_ERR_NOMEM. On success, the resulting inodes will be
168 * appended to the @inode_list, and they will have consistent numbers in their
172 dentry_tree_fix_inodes(struct wim_dentry *root, struct list_head *inode_list)
174 struct inode_fixup_params params;
177 /* We use a hash table to map inode numbers to inodes. */
179 ret = init_inode_table(¶ms.inode_table, 9001);
183 params.num_dir_hard_links = 0;
184 params.num_inconsistent_inodes = 0;
186 for_dentry_in_tree(root, inode_table_insert, ¶ms);
188 /* Generate the resulting list of inodes, and if needed reassign
189 * the inode numbers. */
190 build_inode_list(¶ms.inode_table, inode_list);
191 destroy_inode_table(¶ms.inode_table);
193 if (unlikely(params.num_inconsistent_inodes))
194 WARNING("Fixed %lu invalid hard links in WIM image",
195 params.num_inconsistent_inodes);
197 if (unlikely(params.num_dir_hard_links))
198 WARNING("Ignoring %lu directory hard links",
199 params.num_dir_hard_links);
201 if (unlikely(params.num_inconsistent_inodes ||
202 params.num_dir_hard_links))
203 reassign_inode_numbers(inode_list);