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) 42 { 43 int block_size = max_t(int, msblk->block_size, SQUASHFS_METADATA_SIZE); 44 45 struct squashfs_xz *stream = kmalloc(sizeof(*stream), GFP_KERNEL); 46 if (stream == NULL) 47 goto failed; 48 49 stream->state = xz_dec_init(XZ_PREALLOC, block_size); 50 if (stream->state == NULL) 51 goto failed; 52 53 return stream; 54 55 failed: 56 ERROR("Failed to allocate xz workspace\n"); 57 kfree(stream); 58 return NULL; 59 } 60 61 62 static void squashfs_xz_free(void *strm) 63 { 64 struct squashfs_xz *stream = strm; 65 66 if (stream) { 67 xz_dec_end(stream->state); 68 kfree(stream); 69 } 70 } 71 72 73 static int squashfs_xz_uncompress(struct squashfs_sb_info *msblk, void **buffer, 74 struct buffer_head **bh, int b, int offset, int length, int srclength, 75 int pages) 76 { 77 enum xz_ret xz_err; 78 int avail, total = 0, k = 0, page = 0; 79 struct squashfs_xz *stream = msblk->stream; 80 81 mutex_lock(&msblk->read_data_mutex); 82 83 xz_dec_reset(stream->state); 84 stream->buf.in_pos = 0; 85 stream->buf.in_size = 0; 86 stream->buf.out_pos = 0; 87 stream->buf.out_size = PAGE_CACHE_SIZE; 88 stream->buf.out = buffer[page++]; 89 90 do { 91 if (stream->buf.in_pos == stream->buf.in_size && k < b) { 92 avail = min(length, msblk->devblksize - offset); 93 length -= avail; 94 wait_on_buffer(bh[k]); 95 if (!buffer_uptodate(bh[k])) 96 goto release_mutex; 97 98 stream->buf.in = bh[k]->b_data + offset; 99 stream->buf.in_size = avail; 100 stream->buf.in_pos = 0; 101 offset = 0; 102 } 103 104 if (stream->buf.out_pos == stream->buf.out_size 105 && page < pages) { 106 stream->buf.out = buffer[page++]; 107 stream->buf.out_pos = 0; 108 total += PAGE_CACHE_SIZE; 109 } 110 111 xz_err = xz_dec_run(stream->state, &stream->buf); 112 113 if (stream->buf.in_pos == stream->buf.in_size && k < b) 114 put_bh(bh[k++]); 115 } while (xz_err == XZ_OK); 116 117 if (xz_err != XZ_STREAM_END) { 118 ERROR("xz_dec_run error, data probably corrupt\n"); 119 goto release_mutex; 120 } 121 122 if (k < b) { 123 ERROR("xz_uncompress error, input remaining\n"); 124 goto release_mutex; 125 } 126 127 total += stream->buf.out_pos; 128 mutex_unlock(&msblk->read_data_mutex); 129 return total; 130 131 release_mutex: 132 mutex_unlock(&msblk->read_data_mutex); 133 134 for (; k < b; k++) 135 put_bh(bh[k]); 136 137 return -EIO; 138 } 139 140 const struct squashfs_decompressor squashfs_xz_comp_ops = { 141 .init = squashfs_xz_init, 142 .free = squashfs_xz_free, 143 .decompress = squashfs_xz_uncompress, 144 .id = XZ_COMPRESSION, 145 .name = "xz", 146 .supported = 1 147 }; 148