4 * Support for tagged metadata items that can be appended to WIM directory
9 * Copyright (C) 2014 Eric Biggers
11 * This file is free software; you can redistribute it and/or modify it under
12 * the terms of the GNU Lesser General Public License as published by the Free
13 * Software Foundation; either version 3 of the License, or (at your option) any
16 * This file is distributed in the hope that it will be useful, but WITHOUT
17 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
18 * FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
21 * You should have received a copy of the GNU Lesser General Public License
22 * along with this file; if not, see http://www.gnu.org/licenses/.
29 #include "wimlib/endianness.h"
30 #include "wimlib/inode.h"
31 #include "wimlib/types.h"
32 #include "wimlib/unix_data.h"
34 /* Used by the Microsoft implementation. */
35 #define TAG_OBJECT_ID 0x00000001
37 /* Random number that we'll use for tagging our UNIX data items. */
38 #define TAG_WIMLIB_UNIX_DATA 0x337DD873
40 /* Header that begins each tagged metadata item in the metadata resource */
41 struct tagged_item_header {
43 /* Unique identifier for this item. */
46 /* Size of the data of this tagged item, in bytes. This excludes this
47 * header and should be a multiple of 8.
49 * (Actually, the MS implementation seems to round this up to an 8 byte
50 * boundary when calculating the offset to the next tagged item, but
51 * uses this length unmodified when validating the item. We might as
52 * well do the same.) */
55 /* Variable length data */
59 struct object_id_disk {
61 u8 birth_volume_id[16];
62 u8 birth_object_id[16];
66 struct wimlib_unix_data_disk {
73 /* Retrieves the first tagged item with the specified tag and minimum length
74 * from the WIM inode. Returns a pointer to the tagged data, which can be read
75 * and/or modified in place. Or, if no matching tagged item is found, returns
78 inode_get_tagged_item(const struct wim_inode *inode,
79 u32 desired_tag, u32 min_data_len)
81 size_t minlen_with_hdr = sizeof(struct tagged_item_header) + min_data_len;
82 size_t len_remaining = inode->i_extra_size;
83 u8 *p = inode->i_extra;
85 /* Iterate through the tagged items. */
86 while (len_remaining >= minlen_with_hdr) {
87 struct tagged_item_header *hdr;
91 hdr = (struct tagged_item_header *)p;
92 tag = le32_to_cpu(hdr->tag);
93 len = le32_to_cpu(hdr->length);
95 if (tag == desired_tag && len >= min_data_len)
99 if (len_remaining <= sizeof(struct tagged_item_header) + len)
101 len_remaining -= sizeof(struct tagged_item_header) + len;
102 p += sizeof(struct tagged_item_header) + len;
107 /* Adds a tagged item to a WIM inode and returns a pointer to its uninitialized
108 * data, which must be initialized in-place by the caller. */
110 inode_add_tagged_item(struct wim_inode *inode, u32 tag, u32 len)
115 struct tagged_item_header *hdr;
117 /* We prepend the item instead of appending it because it's easier. */
119 itemsize = sizeof(struct tagged_item_header) + len;
120 newsize = itemsize + inode->i_extra_size;
122 buf = MALLOC(newsize);
126 if (inode->i_extra_size) {
127 memcpy(buf + itemsize, inode->i_extra, inode->i_extra_size);
128 FREE(inode->i_extra);
130 inode->i_extra = buf;
131 inode->i_extra_size = newsize;
133 hdr = (struct tagged_item_header *)buf;
134 hdr->tag = cpu_to_le32(tag);
135 hdr->length = cpu_to_le32(len);
139 static inline struct wimlib_unix_data_disk *
140 inode_get_unix_data_disk(const struct wim_inode *inode)
142 return inode_get_tagged_item(inode, TAG_WIMLIB_UNIX_DATA,
143 sizeof(struct wimlib_unix_data_disk));
146 static inline struct wimlib_unix_data_disk *
147 inode_add_unix_data_disk(struct wim_inode *inode)
149 return inode_add_tagged_item(inode, TAG_WIMLIB_UNIX_DATA,
150 sizeof(struct wimlib_unix_data_disk));
153 /* Returns %true if the specified WIM inode has UNIX data; otherwise %false.
154 * This is a wimlib extension. */
156 inode_has_unix_data(const struct wim_inode *inode)
158 return inode_get_unix_data_disk(inode) != NULL;
161 /* Retrieves UNIX data from the specified WIM inode.
162 * This is a wimlib extension.
164 * Returns %true and fills @unix_data if the inode has UNIX data.
165 * Otherwise returns %false. */
167 inode_get_unix_data(const struct wim_inode *inode,
168 struct wimlib_unix_data *unix_data)
170 const struct wimlib_unix_data_disk *p;
172 p = inode_get_unix_data_disk(inode);
176 unix_data->uid = le32_to_cpu(p->uid);
177 unix_data->gid = le32_to_cpu(p->gid);
178 unix_data->mode = le32_to_cpu(p->mode);
179 unix_data->rdev = le32_to_cpu(p->rdev);
183 /* Sets UNIX data on the specified WIM inode.
184 * This is a wimlib extension.
186 * Callers must specify all members in @unix_data. If the inode does not yet
187 * have UNIX data, it is given these values. Otherwise, only the values that
188 * also have the corresponding flags in @which set are changed.
190 * Returns %true if successful, %false if failed (out of memory). */
192 inode_set_unix_data(struct wim_inode *inode, struct wimlib_unix_data *unix_data,
195 struct wimlib_unix_data_disk *p;
197 p = inode_get_unix_data_disk(inode);
199 p = inode_add_unix_data_disk(inode);
202 which = UNIX_DATA_ALL;
204 if (which & UNIX_DATA_UID)
205 p->uid = cpu_to_le32(unix_data->uid);
206 if (which & UNIX_DATA_GID)
207 p->gid = cpu_to_le32(unix_data->gid);
208 if (which & UNIX_DATA_MODE)
209 p->mode = cpu_to_le32(unix_data->mode);
210 if (which & UNIX_DATA_RDEV)
211 p->rdev = cpu_to_le32(unix_data->rdev);