/* * Squashfs - a compressed read only filesystem for Linux * * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010 * Phillip Lougher <phillip@squashfs.org.uk> * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version 2, * or (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. * * xz_wrapper.c */ #include <linux/mutex.h> #include <linux/buffer_head.h> #include <linux/slab.h> #include <linux/xz.h> #include <linux/bitops.h> #include "squashfs_fs.h" #include "squashfs_fs_sb.h" #include "squashfs.h" #include "decompressor.h" struct squashfs_xz { struct xz_dec *state; struct xz_buf buf; }; struct comp_opts { __le32 dictionary_size; __le32 flags; }; static void *squashfs_xz_init(struct squashfs_sb_info *msblk, void *buff, int len) { struct comp_opts *comp_opts = buff; struct squashfs_xz *stream; int dict_size = msblk->block_size; int err, n; if (comp_opts) { /* check compressor options are the expected length */ if (len < sizeof(*comp_opts)) { err = -EIO; goto failed; } dict_size = le32_to_cpu(comp_opts->dictionary_size); /* the dictionary size should be 2^n or 2^n+2^(n+1) */ n = ffs(dict_size) - 1; if (dict_size != (1 << n) && dict_size != (1 << n) + (1 << (n + 1))) { err = -EIO; goto failed; } } dict_size = max_t(int, dict_size, SQUASHFS_METADATA_SIZE); stream = kmalloc(sizeof(*stream), GFP_KERNEL); if (stream == NULL) { err = -ENOMEM; goto failed; } stream->state = xz_dec_init(XZ_PREALLOC, dict_size); if (stream->state == NULL) { kfree(stream); err = -ENOMEM; goto failed; } return stream; failed: ERROR("Failed to initialise xz decompressor\n"); return ERR_PTR(err); } static void squashfs_xz_free(void *strm) { struct squashfs_xz *stream = strm; if (stream) { xz_dec_end(stream->state); kfree(stream); } } static int squashfs_xz_uncompress(struct squashfs_sb_info *msblk, void **buffer, struct buffer_head **bh, int b, int offset, int length, int srclength, int pages) { enum xz_ret xz_err; int avail, total = 0, k = 0, page = 0; struct squashfs_xz *stream = msblk->stream; mutex_lock(&msblk->read_data_mutex); xz_dec_reset(stream->state); stream->buf.in_pos = 0; stream->buf.in_size = 0; stream->buf.out_pos = 0; stream->buf.out_size = PAGE_CACHE_SIZE; stream->buf.out = buffer[page++]; do { if (stream->buf.in_pos == stream->buf.in_size && k < b) { avail = min(length, msblk->devblksize - offset); length -= avail; wait_on_buffer(bh[k]); if (!buffer_uptodate(bh[k])) goto release_mutex; stream->buf.in = bh[k]->b_data + offset; stream->buf.in_size = avail; stream->buf.in_pos = 0; offset = 0; } if (stream->buf.out_pos == stream->buf.out_size && page < pages) { stream->buf.out = buffer[page++]; stream->buf.out_pos = 0; total += PAGE_CACHE_SIZE; } xz_err = xz_dec_run(stream->state, &stream->buf); if (stream->buf.in_pos == stream->buf.in_size && k < b) put_bh(bh[k++]); } while (xz_err == XZ_OK); if (xz_err != XZ_STREAM_END) { ERROR("xz_dec_run error, data probably corrupt\n"); goto release_mutex; } if (k < b) { ERROR("xz_uncompress error, input remaining\n"); goto release_mutex; } total += stream->buf.out_pos; mutex_unlock(&msblk->read_data_mutex); return total; release_mutex: mutex_unlock(&msblk->read_data_mutex); for (; k < b; k++) put_bh(bh[k]); return -EIO; } const struct squashfs_decompressor squashfs_xz_comp_ops = { .init = squashfs_xz_init, .free = squashfs_xz_free, .decompress = squashfs_xz_uncompress, .id = XZ_COMPRESSION, .name = "xz", .supported = 1 };