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 = 0, zlib_init = 0; 70 int avail, bytes, 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 bytes = length; 79 do { 80 if (stream->avail_in == 0 && k < b) { 81 avail = min(bytes, msblk->devblksize - offset); 82 bytes -= avail; 83 wait_on_buffer(bh[k]); 84 if (!buffer_uptodate(bh[k])) 85 goto release_mutex; 86 87 if (avail == 0) { 88 offset = 0; 89 put_bh(bh[k++]); 90 continue; 91 } 92 93 stream->next_in = bh[k]->b_data + offset; 94 stream->avail_in = avail; 95 offset = 0; 96 } 97 98 if (stream->avail_out == 0 && page < pages) { 99 stream->next_out = buffer[page++]; 100 stream->avail_out = PAGE_CACHE_SIZE; 101 } 102 103 if (!zlib_init) { 104 zlib_err = zlib_inflateInit(stream); 105 if (zlib_err != Z_OK) { 106 ERROR("zlib_inflateInit returned unexpected " 107 "result 0x%x, srclength %d\n", 108 zlib_err, srclength); 109 goto release_mutex; 110 } 111 zlib_init = 1; 112 } 113 114 zlib_err = zlib_inflate(stream, Z_SYNC_FLUSH); 115 116 if (stream->avail_in == 0 && k < b) 117 put_bh(bh[k++]); 118 } while (zlib_err == Z_OK); 119 120 if (zlib_err != Z_STREAM_END) { 121 ERROR("zlib_inflate error, data probably corrupt\n"); 122 goto release_mutex; 123 } 124 125 zlib_err = zlib_inflateEnd(stream); 126 if (zlib_err != Z_OK) { 127 ERROR("zlib_inflate error, data probably corrupt\n"); 128 goto release_mutex; 129 } 130 131 length = stream->total_out; 132 mutex_unlock(&msblk->read_data_mutex); 133 return length; 134 135 release_mutex: 136 mutex_unlock(&msblk->read_data_mutex); 137 138 for (; k < b; k++) 139 put_bh(bh[k]); 140 141 return -EIO; 142 } 143 144 const struct squashfs_decompressor squashfs_zlib_comp_ops = { 145 .init = zlib_init, 146 .free = zlib_free, 147 .decompress = zlib_uncompress, 148 .id = ZLIB_COMPRESSION, 149 .name = "zlib", 150 .supported = 1 151 }; 152 153