ssize_t squashfs_listxattr(struct dentry *d, char *buffer,
size_t buffer_size)
{
struct inode *inode = d->d_inode;
struct super_block *sb = inode->i_sb;
struct squashfs_sb_info *msblk = sb->s_fs_info;
u64 start = SQUASHFS_XATTR_BLK(squashfs_i(inode)->xattr)
+ msblk->xattr_table;
int offset = SQUASHFS_XATTR_OFFSET(squashfs_i(inode)->xattr);
int count = squashfs_i(inode)->xattr_count;
size_t rest = buffer_size;
int err;
/* check that the file system has xattrs */
if (msblk->xattr_id_table == NULL)
return -EOPNOTSUPP;
/* loop reading each xattr name */
while (count--) {
struct squashfs_xattr_entry entry;
struct squashfs_xattr_val val;
const struct xattr_handler *handler;
int name_size, prefix_size = 0;
err = squashfs_read_metadata(sb, &entry, &start, &offset,
sizeof(entry));
if (err < 0)
goto failed;
name_size = le16_to_cpu(entry.size);
handler = squashfs_xattr_handler(le16_to_cpu(entry.type));
if (handler)
prefix_size = handler->list(d, buffer, rest, NULL,
name_size, handler->flags);
if (prefix_size) {
if (buffer) {
if (prefix_size + name_size + 1 > rest) {
err = -ERANGE;
goto failed;
}
buffer += prefix_size;
}
err = squashfs_read_metadata(sb, buffer, &start,
&offset, name_size);
if (err < 0)
goto failed;
if (buffer) {
buffer[name_size] = '\0';
buffer += name_size + 1;
}
rest -= prefix_size + name_size + 1;
} else {
/* no handler or insuffficient privileges, so skip */
err = squashfs_read_metadata(sb, NULL, &start,
&offset, name_size);
if (err < 0)
goto failed;
}
/* skip remaining xattr entry */
err = squashfs_read_metadata(sb, &val, &start, &offset,
sizeof(val));
if (err < 0)
goto failed;
err = squashfs_read_metadata(sb, NULL, &start, &offset,
le32_to_cpu(val.vsize));
if (err < 0)
goto failed;
}
err = buffer_size - rest;
failed:
return err;
}
/*
* Construct and return the list of xattr name:value pairs for the passed xattr
* id
*
* There are two users for get_xattr(), Mksquashfs uses it to read the
* xattrs from the filesystem on appending, and Unsquashfs uses it
* to retrieve the xattrs for writing to disk.
*
* Unfortunately, the two users disagree on what to do with unknown
* xattr prefixes, Mksquashfs wants to treat this as fatal otherwise
* this will cause xattrs to be be lost on appending. Unsquashfs
* on the otherhand wants to retrieve the xattrs which are known and
* to ignore the rest, this allows Unsquashfs to cope more gracefully
* with future versions which may have unknown xattrs, as long as the
* general xattr structure is adhered to, Unsquashfs should be able
* to safely ignore unknown xattrs, and to write the ones it knows about,
* this is better than completely refusing to retrieve all the xattrs.
*
* If ignore is TRUE then don't treat unknown xattr prefixes as
* a failure to read the xattr.
*/
struct xattr_list *get_xattr(int i, unsigned int *count, int ignore) {
long long start;
struct xattr_list *xattr_list = NULL;
unsigned int offset;
void *xptr;
int j = 0, res = 1;
TRACE("get_xattr\n");
*count = xattr_ids[i].count;
start = SQUASHFS_XATTR_BLK(xattr_ids[i].xattr) + xattr_table_start;
offset = SQUASHFS_XATTR_OFFSET(xattr_ids[i].xattr);
xptr = xattrs + get_xattr_block(start) + offset;
TRACE("get_xattr: xattr_id %d, count %d, start %lld, offset %d\n", i, *count, start, offset);
while (j < *count) {
struct squashfs_xattr_entry entry;
struct squashfs_xattr_val val;
if (res != 0) {
xattr_list = realloc(xattr_list, (j + 1) * sizeof(struct xattr_list));
if (xattr_list == NULL)
MEM_ERROR();
}
SQUASHFS_SWAP_XATTR_ENTRY(xptr, &entry);
xptr += sizeof(entry);
res = read_xattr_entry(&xattr_list[j], &entry, xptr);
if (ignore && res == 0) {
/* unknown prefix, but ignore flag is set */
(*count)--;
continue;
}
if (res != 1)
goto failed;
xptr += entry.size;
TRACE("get_xattr: xattr %d, type %d, size %d, name %s\n", j, entry.type, entry.size, xattr_list[j].full_name);
if (entry.type & SQUASHFS_XATTR_VALUE_OOL) {
long long xattr;
void *ool_xptr;
xptr += sizeof(val);
SQUASHFS_SWAP_LONG_LONGS(xptr, &xattr, 1);
xptr += sizeof(xattr);
start = SQUASHFS_XATTR_BLK(xattr) + xattr_table_start;
offset = SQUASHFS_XATTR_OFFSET(xattr);
ool_xptr = xattrs + get_xattr_block(start) + offset;
SQUASHFS_SWAP_XATTR_VAL(ool_xptr, &val);
xattr_list[j].value = ool_xptr + sizeof(val);
} else {
SQUASHFS_SWAP_XATTR_VAL(xptr, &val);
xattr_list[j].value = xptr + sizeof(val);
xptr += sizeof(val) + val.vsize;
}
TRACE("get_xattr: xattr %d, vsize %d\n", j, val.vsize);
xattr_list[j++].vsize = val.vsize;
}
if (*count == 0)
goto failed;
return xattr_list;
failed:
free_xattr(xattr_list, j);
return NULL;
}
static int squashfs_xattr_get(struct inode *inode, int name_index,
const char *name, void *buffer, size_t buffer_size)
{
struct super_block *sb = inode->i_sb;
struct squashfs_sb_info *msblk = sb->s_fs_info;
u64 start = SQUASHFS_XATTR_BLK(squashfs_i(inode)->xattr)
+ msblk->xattr_table;
int offset = SQUASHFS_XATTR_OFFSET(squashfs_i(inode)->xattr);
int count = squashfs_i(inode)->xattr_count;
int name_len = strlen(name);
int err, vsize;
char *target = kmalloc(name_len, GFP_KERNEL);
if (target == NULL)
return -ENOMEM;
/* loop reading each xattr name */
for (; count; count--) {
struct squashfs_xattr_entry entry;
struct squashfs_xattr_val val;
int type, prefix, name_size;
err = squashfs_read_metadata(sb, &entry, &start, &offset,
sizeof(entry));
if (err < 0)
goto failed;
name_size = le16_to_cpu(entry.size);
type = le16_to_cpu(entry.type);
prefix = type & SQUASHFS_XATTR_PREFIX_MASK;
if (prefix == name_index && name_size == name_len)
err = squashfs_read_metadata(sb, target, &start,
&offset, name_size);
else
err = squashfs_read_metadata(sb, NULL, &start,
&offset, name_size);
if (err < 0)
goto failed;
if (prefix == name_index && name_size == name_len &&
strncmp(target, name, name_size) == 0) {
/* found xattr */
if (type & SQUASHFS_XATTR_VALUE_OOL) {
__le64 xattr;
/* val is a reference to the real location */
err = squashfs_read_metadata(sb, &val, &start,
&offset, sizeof(val));
if (err < 0)
goto failed;
err = squashfs_read_metadata(sb, &xattr, &start,
&offset, sizeof(xattr));
if (err < 0)
goto failed;
xattr = le64_to_cpu(xattr);
start = SQUASHFS_XATTR_BLK(xattr) +
msblk->xattr_table;
offset = SQUASHFS_XATTR_OFFSET(xattr);
}
/* read xattr value */
err = squashfs_read_metadata(sb, &val, &start, &offset,
sizeof(val));
if (err < 0)
goto failed;
vsize = le32_to_cpu(val.vsize);
if (buffer) {
if (vsize > buffer_size) {
err = -ERANGE;
goto failed;
}
err = squashfs_read_metadata(sb, buffer, &start,
&offset, vsize);
if (err < 0)
goto failed;
}
break;
}
/* no match, skip remaining xattr entry */
err = squashfs_read_metadata(sb, &val, &start, &offset,
sizeof(val));
if (err < 0)
goto failed;
err = squashfs_read_metadata(sb, NULL, &start, &offset,
le32_to_cpu(val.vsize));
if (err < 0)
goto failed;
}
err = count ? vsize : -ENODATA;
failed:
kfree(target);
return err;
}
/*
* Construct and return the list of xattr name:value pairs for the passed xattr
* id
*/
struct xattr_list *get_xattr(int i, unsigned int *count)
{
long long start;
struct xattr_list *xattr_list = NULL;
unsigned int offset;
void *xptr;
int j;
TRACE("get_xattr\n");
*count = xattr_ids[i].count;
start = SQUASHFS_XATTR_BLK(xattr_ids[i].xattr) + xattr_table_start;
offset = SQUASHFS_XATTR_OFFSET(xattr_ids[i].xattr);
xptr = xattrs + get_xattr_block(start) + offset;
TRACE("get_xattr: xattr_id %d, count %d, start %lld, offset %d\n", i,
*count, start, offset);
for(j = 0; j < *count; j++) {
struct squashfs_xattr_entry entry;
struct squashfs_xattr_val val;
int res;
xattr_list = realloc(xattr_list, (j + 1) *
sizeof(struct xattr_list));
if(xattr_list == NULL) {
ERROR("Out of memory in get_xattrs\n");
goto failed;
}
SQUASHFS_SWAP_XATTR_ENTRY(&entry, xptr);
xptr += sizeof(entry);
res = read_xattr_entry(&xattr_list[j], &entry, xptr);
if(res != 1)
goto failed;
xptr += entry.size;
TRACE("get_xattr: xattr %d, type %d, size %d, name %s\n", j,
entry.type, entry.size, xattr_list[j].full_name);
if(entry.type & SQUASHFS_XATTR_VALUE_OOL) {
long long xattr;
void *ool_xptr;
xptr += sizeof(val);
SQUASHFS_SWAP_LONG_LONGS(&xattr, xptr, 1);
xptr += sizeof(xattr);
start = SQUASHFS_XATTR_BLK(xattr) + xattr_table_start;
offset = SQUASHFS_XATTR_OFFSET(xattr);
ool_xptr = xattrs + get_xattr_block(start) + offset;
SQUASHFS_SWAP_XATTR_VAL(&val, ool_xptr);
xattr_list[j].value = ool_xptr + sizeof(val);
} else {
SQUASHFS_SWAP_XATTR_VAL(&val, xptr);
xattr_list[j].value = xptr + sizeof(val);
xptr += sizeof(val) + val.vsize;
}
TRACE("get_xattr: xattr %d, vsize %d\n", j, val.vsize);
xattr_list[j].vsize = val.vsize;
}
return xattr_list;
failed:
free(xattr_list);
return NULL;
}
