static int zlib_uncompress(struct squashfs_sb_info *msblk, void *strm,
struct buffer_head **bh, int b, int offset, int length,
struct squashfs_page_actor *output)
{
int zlib_err, zlib_init = 0, k = 0;
z_stream *stream = strm;
stream->avail_out = PAGE_SIZE;
stream->next_out = squashfs_first_page(output);
stream->avail_in = 0;
do {
if (stream->avail_in == 0 && k < b) {
int avail = min(length, msblk->devblksize - offset);
length -= avail;
stream->next_in = bh[k]->b_data + offset;
stream->avail_in = avail;
offset = 0;
}
if (stream->avail_out == 0) {
stream->next_out = squashfs_next_page(output);
if (stream->next_out != NULL)
stream->avail_out = PAGE_SIZE;
}
if (!zlib_init) {
zlib_err = zlib_inflateInit(stream);
if (zlib_err != Z_OK) {
squashfs_finish_page(output);
goto out;
}
zlib_init = 1;
}
zlib_err = zlib_inflate(stream, Z_SYNC_FLUSH);
if (stream->avail_in == 0 && k < b)
put_bh(bh[k++]);
} while (zlib_err == Z_OK);
squashfs_finish_page(output);
if (zlib_err != Z_STREAM_END)
goto out;
zlib_err = zlib_inflateEnd(stream);
if (zlib_err != Z_OK)
goto out;
if (k < b)
goto out;
return stream->total_out;
out:
for (; k < b; k++)
put_bh(bh[k]);
return -EIO;
}
/*
* Read and decompress a metadata block or datablock. Length is non-zero
* if a datablock is being read (the size is stored elsewhere in the
* filesystem), otherwise the length is obtained from the first two bytes of
* the metadata block. A bit in the length field indicates if the block
* is stored uncompressed in the filesystem (usually because compression
* generated a larger block - this does occasionally happen with compression
* algorithms).
*/
int squashfs_read_data(struct super_block *sb, u64 index, int length,
u64 *next_index, struct squashfs_page_actor *output)
{
struct squashfs_sb_info *msblk = sb->s_fs_info;
struct buffer_head **bh;
int offset = index & ((1 << msblk->devblksize_log2) - 1);
u64 cur_index = index >> msblk->devblksize_log2;
int bytes, compressed, b = 0, k = 0, avail, i;
bh = kcalloc(((output->length + msblk->devblksize - 1)
>> msblk->devblksize_log2) + 1, sizeof(*bh), GFP_KERNEL);
if (bh == NULL)
return -ENOMEM;
if (length) {
/*
* Datablock.
*/
bytes = -offset;
compressed = SQUASHFS_COMPRESSED_BLOCK(length);
length = SQUASHFS_COMPRESSED_SIZE_BLOCK(length);
if (next_index)
*next_index = index + length;
TRACE("Block @ 0x%llx, %scompressed size %d, src size %d\n",
index, compressed ? "" : "un", length, output->length);
if (length < 0 || length > output->length ||
(index + length) > msblk->bytes_used)
goto read_failure;
for (b = 0; bytes < length; b++, cur_index++) {
bh[b] = sb_getblk(sb, cur_index);
if (bh[b] == NULL)
goto block_release;
bytes += msblk->devblksize;
}
ll_rw_block(REQ_OP_READ, 0, b, bh);
} else {
/*
* Metadata block.
*/
if ((index + 2) > msblk->bytes_used)
goto read_failure;
bh[0] = get_block_length(sb, &cur_index, &offset, &length);
if (bh[0] == NULL)
goto read_failure;
b = 1;
bytes = msblk->devblksize - offset;
compressed = SQUASHFS_COMPRESSED(length);
length = SQUASHFS_COMPRESSED_SIZE(length);
if (next_index)
*next_index = index + length + 2;
TRACE("Block @ 0x%llx, %scompressed size %d\n", index,
compressed ? "" : "un", length);
if (length < 0 || length > output->length ||
(index + length) > msblk->bytes_used)
goto block_release;
for (; bytes < length; b++) {
bh[b] = sb_getblk(sb, ++cur_index);
if (bh[b] == NULL)
goto block_release;
bytes += msblk->devblksize;
}
ll_rw_block(REQ_OP_READ, 0, b - 1, bh + 1);
}
for (i = 0; i < b; i++) {
wait_on_buffer(bh[i]);
if (!buffer_uptodate(bh[i]))
goto block_release;
}
if (compressed) {
length = squashfs_decompress(msblk, bh, b, offset, length,
output);
if (length < 0)
goto read_failure;
} else {
/*
* Block is uncompressed.
*/
int in, pg_offset = 0;
void *data = squashfs_first_page(output);
for (bytes = length; k < b; k++) {
in = min(bytes, msblk->devblksize - offset);
bytes -= in;
while (in) {
if (pg_offset == PAGE_SIZE) {
data = squashfs_next_page(output);
pg_offset = 0;
}
avail = min_t(int, in, PAGE_SIZE -
pg_offset);
memcpy(data + pg_offset, bh[k]->b_data + offset,
avail);
in -= avail;
pg_offset += avail;
offset += avail;
}
offset = 0;
put_bh(bh[k]);
}
squashfs_finish_page(output);
}
kfree(bh);
return length;
block_release:
for (; k < b; k++)
put_bh(bh[k]);
read_failure:
ERROR("squashfs_read_data failed to read block 0x%llx\n",
(unsigned long long) index);
kfree(bh);
return -EIO;
}
