1 /* 2 * Squashfs - a compressed read only filesystem for Linux 3 * 4 * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009 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 * zlib_wrapper.c 22 */ 23 24 25 #include <linux/mutex.h> 26 #include <linux/buffer_head.h> 27 #include <linux/slab.h> 28 #include <linux/zlib.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 static void *zlib_init(struct squashfs_sb_info *dummy) 37 { 38 z_stream *stream = kmalloc(sizeof(z_stream), GFP_KERNEL); 39 if (stream == NULL) 40 goto failed; 41 stream->workspace = kmalloc(zlib_inflate_workspacesize(), 42 GFP_KERNEL); 43 if (stream->workspace == NULL) 44 goto failed; 45 46 return stream; 47 48 failed: 49 ERROR("Failed to allocate zlib workspace\n"); 50 kfree(stream); 51 return NULL; 52 } 53 54 55 static void zlib_free(void *strm) 56 { 57 z_stream *stream = strm; 58 59 if (stream) 60 kfree(stream->workspace); 61 kfree(stream); 62 } 63 64 65 static int zlib_uncompress(struct squashfs_sb_info *msblk, void **buffer, 66 struct buffer_head **bh, int b, int offset, int length, int srclength, 67 int pages) 68 { 69 int zlib_err, zlib_init = 0; 70 int k = 0, page = 0; 71 z_stream *stream = msblk->stream; 72 73 mutex_lock(&msblk->read_data_mutex); 74 75 stream->avail_out = 0; 76 stream->avail_in = 0; 77 78 do { 79 if (stream->avail_in == 0 && k < b) { 80 int avail = min(length, msblk->devblksize - offset); 81 length -= avail; 82 wait_on_buffer(bh[k]); 83 if (!buffer_uptodate(bh[k])) 84 goto release_mutex; 85 86 if (avail == 0) { 87 offset = 0; 88 put_bh(bh[k++]); 89 continue; 90 } 91 92 stream->next_in = bh[k]->b_data + offset; 93 stream->avail_in = avail; 94 offset = 0; 95 } 96 97 if (stream->avail_out == 0 && page < pages) { 98 stream->next_out = buffer[page++]; 99 stream->avail_out = PAGE_CACHE_SIZE; 100 } 101 102 if (!zlib_init) { 103 zlib_err = zlib_inflateInit(stream); 104 if (zlib_err != Z_OK) { 105 ERROR("zlib_inflateInit returned unexpected " 106 "result 0x%x, srclength %d\n", 107 zlib_err, srclength); 108 goto release_mutex; 109 } 110 zlib_init = 1; 111 } 112 113 zlib_err = zlib_inflate(stream, Z_SYNC_FLUSH); 114 115 if (stream->avail_in == 0 && k < b) 116 put_bh(bh[k++]); 117 } while (zlib_err == Z_OK); 118 119 if (zlib_err != Z_STREAM_END) { 120 ERROR("zlib_inflate error, data probably corrupt\n"); 121 goto release_mutex; 122 } 123 124 zlib_err = zlib_inflateEnd(stream); 125 if (zlib_err != Z_OK) { 126 ERROR("zlib_inflate error, data probably corrupt\n"); 127 goto release_mutex; 128 } 129 130 if (k < b) { 131 ERROR("zlib_uncompress error, data remaining\n"); 132 goto release_mutex; 133 } 134 135 length = stream->total_out; 136 mutex_unlock(&msblk->read_data_mutex); 137 return length; 138 139 release_mutex: 140 mutex_unlock(&msblk->read_data_mutex); 141 142 for (; k < b; k++) 143 put_bh(bh[k]); 144 145 return -EIO; 146 } 147 148 const struct squashfs_decompressor squashfs_zlib_comp_ops = { 149 .init = zlib_init, 150 .free = zlib_free, 151 .decompress = zlib_uncompress, 152 .id = ZLIB_COMPRESSION, 153 .name = "zlib", 154 .supported = 1 155 }; 156 157