2 * Copyright (C) 2010 The Android Open Source Project
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
21 #ifdef HAVE_ANDROID_OS
22 #include <linux/capability.h>
24 #include <private/android_filesystem_capability.h>
27 #define XATTR_SELINUX_SUFFIX "selinux"
28 #define XATTR_CAPS_SUFFIX "capability"
30 #include "ext4_utils.h"
31 #include "make_ext4fs.h"
38 #define S_IFLNK 0 /* used by make_link, not needed under mingw */
41 static u32 dentry_size(u32 entries, struct dentry *dentries)
45 unsigned int dentry_len;
47 for (i = 0; i < entries; i++) {
48 dentry_len = 8 + EXT4_ALIGN(strlen(dentries[i].filename), 4);
49 if (len % info.block_size + dentry_len > info.block_size)
50 len += info.block_size - (len % info.block_size);
57 static struct ext4_dir_entry_2 *add_dentry(u8 *data, u32 *offset,
58 struct ext4_dir_entry_2 *prev, u32 inode, const char *name,
61 u8 name_len = strlen(name);
62 u16 rec_len = 8 + EXT4_ALIGN(name_len, 4);
63 struct ext4_dir_entry_2 *dentry;
65 u32 start_block = *offset / info.block_size;
66 u32 end_block = (*offset + rec_len - 1) / info.block_size;
67 if (start_block != end_block) {
68 /* Adding this dentry will cross a block boundary, so pad the previous
69 dentry to the block boundary */
71 critical_error("no prev");
72 prev->rec_len += end_block * info.block_size - *offset;
73 *offset = end_block * info.block_size;
76 dentry = (struct ext4_dir_entry_2 *)(data + *offset);
77 dentry->inode = inode;
78 dentry->rec_len = rec_len;
79 dentry->name_len = name_len;
80 dentry->file_type = file_type;
81 memcpy(dentry->name, name, name_len);
87 /* Creates a directory structure for an array of directory entries, dentries,
88 and stores the location of the structure in an inode. The new inode's
89 .. link is set to dir_inode_num. Stores the location of the inode number
90 of each directory entry into dentries[i].inode, to be filled in later
91 when the inode for the entry is allocated. Returns the inode number of the
93 u32 make_directory(u32 dir_inode_num, u32 entries, struct dentry *dentries,
96 struct ext4_inode *inode;
103 struct ext4_dir_entry_2 *dentry;
105 blocks = DIV_ROUND_UP(dentry_size(entries, dentries), info.block_size);
106 len = blocks * info.block_size;
109 inode_num = allocate_inode(info);
111 dir_inode_num = EXT4_ROOT_INO;
112 inode_num = EXT4_ROOT_INO;
115 if (inode_num == EXT4_ALLOCATE_FAILED) {
116 error("failed to allocate inode\n");
117 return EXT4_ALLOCATE_FAILED;
120 add_directory(inode_num);
122 inode = get_inode(inode_num);
124 error("failed to get inode %u", inode_num);
125 return EXT4_ALLOCATE_FAILED;
128 data = inode_allocate_data_extents(inode, len, len);
130 error("failed to allocate %u extents", len);
131 return EXT4_ALLOCATE_FAILED;
134 inode->i_mode = S_IFDIR;
135 inode->i_links_count = dirs + 2;
136 inode->i_flags |= aux_info.default_i_flags;
140 dentry = add_dentry(data, &offset, NULL, inode_num, ".", EXT4_FT_DIR);
142 error("failed to add . directory");
143 return EXT4_ALLOCATE_FAILED;
146 dentry = add_dentry(data, &offset, dentry, dir_inode_num, "..", EXT4_FT_DIR);
148 error("failed to add .. directory");
149 return EXT4_ALLOCATE_FAILED;
152 for (i = 0; i < entries; i++) {
153 dentry = add_dentry(data, &offset, dentry, 0,
154 dentries[i].filename, dentries[i].file_type);
155 if (offset > len || (offset == len && i != entries - 1))
156 critical_error("internal error: dentry for %s ends at %d, past %d\n",
157 dentries[i].filename, offset, len);
158 dentries[i].inode = &dentry->inode;
160 error("failed to add directory");
161 return EXT4_ALLOCATE_FAILED;
165 /* pad the last dentry out to the end of the block */
166 dentry->rec_len += len - offset;
171 /* Creates a file on disk. Returns the inode number of the new file */
172 u32 make_file(const char *filename, u64 len)
174 struct ext4_inode *inode;
177 inode_num = allocate_inode(info);
178 if (inode_num == EXT4_ALLOCATE_FAILED) {
179 error("failed to allocate inode\n");
180 return EXT4_ALLOCATE_FAILED;
183 inode = get_inode(inode_num);
185 error("failed to get inode %u", inode_num);
186 return EXT4_ALLOCATE_FAILED;
190 inode_allocate_file_extents(inode, len, filename);
192 inode->i_mode = S_IFREG;
193 inode->i_links_count = 1;
194 inode->i_flags |= aux_info.default_i_flags;
199 /* Creates a file on disk. Returns the inode number of the new file */
200 u32 make_link(const char *link)
202 struct ext4_inode *inode;
204 u32 len = strlen(link);
206 inode_num = allocate_inode(info);
207 if (inode_num == EXT4_ALLOCATE_FAILED) {
208 error("failed to allocate inode\n");
209 return EXT4_ALLOCATE_FAILED;
212 inode = get_inode(inode_num);
214 error("failed to get inode %u", inode_num);
215 return EXT4_ALLOCATE_FAILED;
218 inode->i_mode = S_IFLNK;
219 inode->i_links_count = 1;
220 inode->i_flags |= aux_info.default_i_flags;
221 inode->i_size_lo = len;
223 if (len + 1 <= sizeof(inode->i_block)) {
225 memcpy((char*)inode->i_block, link, len);
227 u8 *data = inode_allocate_data_indirect(inode, info.block_size, info.block_size);
228 memcpy(data, link, len);
229 inode->i_blocks_lo = info.block_size / 512;
235 int inode_set_permissions(u32 inode_num, u16 mode, u16 uid, u16 gid, u32 mtime)
237 struct ext4_inode *inode = get_inode(inode_num);
242 inode->i_mode |= mode;
245 inode->i_mtime = mtime;
246 inode->i_atime = mtime;
247 inode->i_ctime = mtime;
253 * Returns the amount of free space available in the specified
256 static size_t xattr_free_space(struct ext4_xattr_entry *entry, char *end)
258 while(!IS_LAST_ENTRY(entry) && (((char *) entry) < end)) {
259 end -= EXT4_XATTR_SIZE(le32_to_cpu(entry->e_value_size));
260 entry = EXT4_XATTR_NEXT(entry);
263 if (((char *) entry) > end) {
264 error("unexpected read beyond end of xattr space");
268 return end - ((char *) entry);
272 * Returns a pointer to the free space immediately after the
275 static struct ext4_xattr_entry* xattr_get_last(struct ext4_xattr_entry *entry)
277 for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
284 * assert that the elements in the ext4 xattr section are in sorted order
286 * The ext4 filesystem requires extended attributes to be sorted when
287 * they're not stored in the inode. The kernel ext4 code uses the following
290 * 1) First sort extended attributes by their name_index. For example,
291 * EXT4_XATTR_INDEX_USER (1) comes before EXT4_XATTR_INDEX_SECURITY (6).
292 * 2) If the name_indexes are equal, then sorting is based on the length
293 * of the name. For example, XATTR_SELINUX_SUFFIX ("selinux") comes before
294 * XATTR_CAPS_SUFFIX ("capability") because "selinux" is shorter than "capability"
295 * 3) If the name_index and name_length are equal, then memcmp() is used to determine
296 * which name comes first. For example, "selinux" would come before "yelinux".
298 * This method is intended to implement the sorting function defined in
299 * the Linux kernel file fs/ext4/xattr.c function ext4_xattr_find_entry().
301 static void xattr_assert_sane(struct ext4_xattr_entry *entry)
303 for( ; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
304 struct ext4_xattr_entry *next = EXT4_XATTR_NEXT(entry);
305 if (IS_LAST_ENTRY(next)) {
309 int cmp = next->e_name_index - entry->e_name_index;
311 cmp = next->e_name_len - entry->e_name_len;
313 cmp = memcmp(next->e_name, entry->e_name, next->e_name_len);
315 error("BUG: extended attributes are not sorted\n");
319 error("BUG: duplicate extended attributes detected\n");
325 #define NAME_HASH_SHIFT 5
326 #define VALUE_HASH_SHIFT 16
328 static void ext4_xattr_hash_entry(struct ext4_xattr_header *header,
329 struct ext4_xattr_entry *entry)
332 char *name = entry->e_name;
335 for (n = 0; n < entry->e_name_len; n++) {
336 hash = (hash << NAME_HASH_SHIFT) ^
337 (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
341 if (entry->e_value_block == 0 && entry->e_value_size != 0) {
342 u32 *value = (u32 *)((char *)header +
343 le16_to_cpu(entry->e_value_offs));
344 for (n = (le32_to_cpu(entry->e_value_size) +
345 EXT4_XATTR_ROUND) >> EXT4_XATTR_PAD_BITS; n; n--) {
346 hash = (hash << VALUE_HASH_SHIFT) ^
347 (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^
348 le32_to_cpu(*value++);
351 entry->e_hash = cpu_to_le32(hash);
354 #undef NAME_HASH_SHIFT
355 #undef VALUE_HASH_SHIFT
357 static struct ext4_xattr_entry* xattr_addto_range(
360 struct ext4_xattr_entry *first,
366 size_t name_len = strlen(name);
370 size_t available_size = xattr_free_space(first, block_end);
371 size_t needed_size = EXT4_XATTR_LEN(name_len) + EXT4_XATTR_SIZE(value_len);
373 if (needed_size > available_size)
376 struct ext4_xattr_entry *new_entry = xattr_get_last(first);
377 memset(new_entry, 0, EXT4_XATTR_LEN(name_len));
379 new_entry->e_name_len = name_len;
380 new_entry->e_name_index = name_index;
381 memcpy(new_entry->e_name, name, name_len);
382 new_entry->e_value_block = 0;
383 new_entry->e_value_size = cpu_to_le32(value_len);
385 char *val = (char *) new_entry + available_size - EXT4_XATTR_SIZE(value_len);
386 size_t e_value_offs = val - (char *) block_start;
388 new_entry->e_value_offs = cpu_to_le16(e_value_offs);
389 memset(val, 0, EXT4_XATTR_SIZE(value_len));
390 memcpy(val, value, value_len);
392 xattr_assert_sane(first);
396 static int xattr_addto_inode(struct ext4_inode *inode, int name_index,
397 const char *name, const void *value, size_t value_len)
399 struct ext4_xattr_ibody_header *hdr = (struct ext4_xattr_ibody_header *) (inode + 1);
400 struct ext4_xattr_entry *first = (struct ext4_xattr_entry *) (hdr + 1);
401 char *block_end = ((char *) inode) + info.inode_size;
403 struct ext4_xattr_entry *result =
404 xattr_addto_range(first, block_end, first, name_index, name, value, value_len);
409 hdr->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
410 inode->i_extra_isize = cpu_to_le16(sizeof(struct ext4_inode) - EXT4_GOOD_OLD_INODE_SIZE);
415 static int xattr_addto_block(struct ext4_inode *inode, int name_index,
416 const char *name, const void *value, size_t value_len)
418 struct ext4_xattr_header *header = get_xattr_block_for_inode(inode);
422 struct ext4_xattr_entry *first = (struct ext4_xattr_entry *) (header + 1);
423 char *block_end = ((char *) header) + info.block_size;
425 struct ext4_xattr_entry *result =
426 xattr_addto_range(header, block_end, first, name_index, name, value, value_len);
431 ext4_xattr_hash_entry(header, result);
436 static int xattr_add(u32 inode_num, int name_index, const char *name,
437 const void *value, size_t value_len)
442 struct ext4_inode *inode = get_inode(inode_num);
447 int result = xattr_addto_inode(inode, name_index, name, value, value_len);
449 result = xattr_addto_block(inode, name_index, name, value, value_len);
454 int inode_set_selinux(u32 inode_num, const char *secon)
459 return xattr_add(inode_num, EXT4_XATTR_INDEX_SECURITY,
460 XATTR_SELINUX_SUFFIX, secon, strlen(secon) + 1);
463 int inode_set_capabilities(u32 inode_num, uint64_t capabilities) {
464 if (capabilities == 0)
467 struct vfs_cap_data cap_data;
468 memset(&cap_data, 0, sizeof(cap_data));
470 cap_data.magic_etc = VFS_CAP_REVISION | VFS_CAP_FLAGS_EFFECTIVE;
471 cap_data.data[0].permitted = (uint32_t) (capabilities & 0xffffffff);
472 cap_data.data[0].inheritable = 0;
473 cap_data.data[1].permitted = (uint32_t) (capabilities >> 32);
474 cap_data.data[1].inheritable = 0;
476 return xattr_add(inode_num, EXT4_XATTR_INDEX_SECURITY,
477 XATTR_CAPS_SUFFIX, &cap_data, sizeof(cap_data));