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 #include <linux/vmalloc.h> 30 31 #include "squashfs_fs.h" 32 #include "squashfs_fs_sb.h" 33 #include "squashfs.h" 34 #include "decompressor.h" 35 36 static void *zlib_init(struct squashfs_sb_info *dummy, void *buff, int len) 37 { 38 z_stream *stream = kmalloc(sizeof(z_stream), GFP_KERNEL); 39 if (stream == NULL) 40 goto failed; 41 stream->workspace = vmalloc(zlib_inflate_workspacesize()); 42 if (stream->workspace == NULL) 43 goto failed; 44 45 return stream; 46 47 failed: 48 ERROR("Failed to allocate zlib workspace\n"); 49 kfree(stream); 50 return ERR_PTR(-ENOMEM); 51 } 52 53 54 static void zlib_free(void *strm) 55 { 56 z_stream *stream = strm; 57 58 if (stream) 59 vfree(stream->workspace); 60 kfree(stream); 61 } 62 63 64 static int zlib_uncompress(struct squashfs_sb_info *msblk, void **buffer, 65 struct buffer_head **bh, int b, int offset, int length, int srclength, 66 int pages) 67 { 68 int zlib_err, zlib_init = 0; 69 int k = 0, page = 0; 70 z_stream *stream = msblk->stream; 71 72 mutex_lock(&msblk->read_data_mutex); 73 74 stream->avail_out = 0; 75 stream->avail_in = 0; 76 77 do { 78 if (stream->avail_in == 0 && k < b) { 79 int avail = min(length, msblk->devblksize - offset); 80 length -= avail; 81 wait_on_buffer(bh[k]); 82 if (!buffer_uptodate(bh[k])) 83 goto release_mutex; 84 85 stream->next_in = bh[k]->b_data + offset; 86 stream->avail_in = avail; 87 offset = 0; 88 } 89 90 if (stream->avail_out == 0 && page < pages) { 91 stream->next_out = buffer[page++]; 92 stream->avail_out = PAGE_CACHE_SIZE; 93 } 94 95 if (!zlib_init) { 96 zlib_err = zlib_inflateInit(stream); 97 if (zlib_err != Z_OK) { 98 ERROR("zlib_inflateInit returned unexpected " 99 "result 0x%x, srclength %d\n", 100 zlib_err, srclength); 101 goto release_mutex; 102 } 103 zlib_init = 1; 104 } 105 106 zlib_err = zlib_inflate(stream, Z_SYNC_FLUSH); 107 108 if (stream->avail_in == 0 && k < b) 109 put_bh(bh[k++]); 110 } while (zlib_err == Z_OK); 111 112 if (zlib_err != Z_STREAM_END) { 113 ERROR("zlib_inflate error, data probably corrupt\n"); 114 goto release_mutex; 115 } 116 117 zlib_err = zlib_inflateEnd(stream); 118 if (zlib_err != Z_OK) { 119 ERROR("zlib_inflate error, data probably corrupt\n"); 120 goto release_mutex; 121 } 122 123 if (k < b) { 124 ERROR("zlib_uncompress error, data remaining\n"); 125 goto release_mutex; 126 } 127 128 length = stream->total_out; 129 mutex_unlock(&msblk->read_data_mutex); 130 return length; 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_zlib_comp_ops = { 142 .init = zlib_init, 143 .free = zlib_free, 144 .decompress = zlib_uncompress, 145 .id = ZLIB_COMPRESSION, 146 .name = "zlib", 147 .supported = 1 148 }; 149 150