1 /* 2 * Squashfs - a compressed read only filesystem for Linux 3 * 4 * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010 5 * Phillip Lougher <phillip@lougher.demon.co.uk> 6 * 7 * This program is free software; you can redistribute it and/or 8 * modify it under the terms of the GNU General Public License 9 * as published by the Free Software Foundation; either version 2, 10 * or (at your option) any later version. 11 * 12 * This program is distributed in the hope that it will be useful, 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 * GNU General Public License for more details. 16 * 17 * You should have received a copy of the GNU General Public License 18 * along with this program; if not, write to the Free Software 19 * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. 20 * 21 * xz_wrapper.c 22 */ 23 24 25 #include <linux/mutex.h> 26 #include <linux/buffer_head.h> 27 #include <linux/slab.h> 28 #include <linux/xz.h> 29 30 #include "squashfs_fs.h" 31 #include "squashfs_fs_sb.h" 32 #include "squashfs_fs_i.h" 33 #include "squashfs.h" 34 #include "decompressor.h" 35 36 struct squashfs_xz { 37 struct xz_dec *state; 38 struct xz_buf buf; 39 }; 40 41 static void *squashfs_xz_init(struct squashfs_sb_info *msblk, void *buff, 42 int len) 43 { 44 int block_size = max_t(int, msblk->block_size, SQUASHFS_METADATA_SIZE); 45 46 struct squashfs_xz *stream = kmalloc(sizeof(*stream), GFP_KERNEL); 47 if (stream == NULL) 48 goto failed; 49 50 stream->state = xz_dec_init(XZ_PREALLOC, block_size); 51 if (stream->state == NULL) 52 goto failed; 53 54 return stream; 55 56 failed: 57 ERROR("Failed to allocate xz workspace\n"); 58 kfree(stream); 59 return ERR_PTR(-ENOMEM); 60 } 61 62 63 static void squashfs_xz_free(void *strm) 64 { 65 struct squashfs_xz *stream = strm; 66 67 if (stream) { 68 xz_dec_end(stream->state); 69 kfree(stream); 70 } 71 } 72 73 74 static int squashfs_xz_uncompress(struct squashfs_sb_info *msblk, void **buffer, 75 struct buffer_head **bh, int b, int offset, int length, int srclength, 76 int pages) 77 { 78 enum xz_ret xz_err; 79 int avail, total = 0, k = 0, page = 0; 80 struct squashfs_xz *stream = msblk->stream; 81 82 mutex_lock(&msblk->read_data_mutex); 83 84 xz_dec_reset(stream->state); 85 stream->buf.in_pos = 0; 86 stream->buf.in_size = 0; 87 stream->buf.out_pos = 0; 88 stream->buf.out_size = PAGE_CACHE_SIZE; 89 stream->buf.out = buffer[page++]; 90 91 do { 92 if (stream->buf.in_pos == stream->buf.in_size && k < b) { 93 avail = min(length, msblk->devblksize - offset); 94 length -= avail; 95 wait_on_buffer(bh[k]); 96 if (!buffer_uptodate(bh[k])) 97 goto release_mutex; 98 99 stream->buf.in = bh[k]->b_data + offset; 100 stream->buf.in_size = avail; 101 stream->buf.in_pos = 0; 102 offset = 0; 103 } 104 105 if (stream->buf.out_pos == stream->buf.out_size 106 && page < pages) { 107 stream->buf.out = buffer[page++]; 108 stream->buf.out_pos = 0; 109 total += PAGE_CACHE_SIZE; 110 } 111 112 xz_err = xz_dec_run(stream->state, &stream->buf); 113 114 if (stream->buf.in_pos == stream->buf.in_size && k < b) 115 put_bh(bh[k++]); 116 } while (xz_err == XZ_OK); 117 118 if (xz_err != XZ_STREAM_END) { 119 ERROR("xz_dec_run error, data probably corrupt\n"); 120 goto release_mutex; 121 } 122 123 if (k < b) { 124 ERROR("xz_uncompress error, input remaining\n"); 125 goto release_mutex; 126 } 127 128 total += stream->buf.out_pos; 129 mutex_unlock(&msblk->read_data_mutex); 130 return total; 131 132 release_mutex: 133 mutex_unlock(&msblk->read_data_mutex); 134 135 for (; k < b; k++) 136 put_bh(bh[k]); 137 138 return -EIO; 139 } 140 141 const struct squashfs_decompressor squashfs_xz_comp_ops = { 142 .init = squashfs_xz_init, 143 .free = squashfs_xz_free, 144 .decompress = squashfs_xz_uncompress, 145 .id = XZ_COMPRESSION, 146 .name = "xz", 147 .supported = 1 148 }; 149