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/zlib.h> 28 29 #include "squashfs_fs.h" 30 #include "squashfs_fs_sb.h" 31 #include "squashfs_fs_i.h" 32 #include "squashfs.h" 33 34 void *squashfs_zlib_init() 35 { 36 z_stream *stream = kmalloc(sizeof(z_stream), GFP_KERNEL); 37 if (stream == NULL) 38 goto failed; 39 stream->workspace = kmalloc(zlib_inflate_workspacesize(), 40 GFP_KERNEL); 41 if (stream->workspace == NULL) 42 goto failed; 43 44 return stream; 45 46 failed: 47 ERROR("Failed to allocate zlib workspace\n"); 48 kfree(stream); 49 return NULL; 50 } 51 52 53 void squashfs_zlib_free(void *strm) 54 { 55 z_stream *stream = strm; 56 57 if (stream) 58 kfree(stream->workspace); 59 kfree(stream); 60 } 61 62 63 int squashfs_zlib_uncompress(struct squashfs_sb_info *msblk, void **buffer, 64 struct buffer_head **bh, int b, int offset, int length, int srclength, 65 int pages) 66 { 67 int zlib_err = 0, zlib_init = 0; 68 int avail, bytes, k = 0, page = 0; 69 z_stream *stream = msblk->stream; 70 71 mutex_lock(&msblk->read_data_mutex); 72 73 stream->avail_out = 0; 74 stream->avail_in = 0; 75 76 bytes = length; 77 do { 78 if (stream->avail_in == 0 && k < b) { 79 avail = min(bytes, msblk->devblksize - offset); 80 bytes -= avail; 81 wait_on_buffer(bh[k]); 82 if (!buffer_uptodate(bh[k])) 83 goto release_mutex; 84 85 if (avail == 0) { 86 offset = 0; 87 put_bh(bh[k++]); 88 continue; 89 } 90 91 stream->next_in = bh[k]->b_data + offset; 92 stream->avail_in = avail; 93 offset = 0; 94 } 95 96 if (stream->avail_out == 0 && page < pages) { 97 stream->next_out = buffer[page++]; 98 stream->avail_out = PAGE_CACHE_SIZE; 99 } 100 101 if (!zlib_init) { 102 zlib_err = zlib_inflateInit(stream); 103 if (zlib_err != Z_OK) { 104 ERROR("zlib_inflateInit returned unexpected " 105 "result 0x%x, srclength %d\n", 106 zlib_err, srclength); 107 goto release_mutex; 108 } 109 zlib_init = 1; 110 } 111 112 zlib_err = zlib_inflate(stream, Z_SYNC_FLUSH); 113 114 if (stream->avail_in == 0 && k < b) 115 put_bh(bh[k++]); 116 } while (zlib_err == Z_OK); 117 118 if (zlib_err != Z_STREAM_END) { 119 ERROR("zlib_inflate error, data probably corrupt\n"); 120 goto release_mutex; 121 } 122 123 zlib_err = zlib_inflateEnd(stream); 124 if (zlib_err != Z_OK) { 125 ERROR("zlib_inflate error, data probably corrupt\n"); 126 goto release_mutex; 127 } 128 129 mutex_unlock(&msblk->read_data_mutex); 130 return stream->total_out; 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