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 int squashfs_zlib_uncompress(struct squashfs_sb_info *msblk, void **buffer, 35 struct buffer_head **bh, int b, int offset, int length, int srclength, 36 int pages) 37 { 38 int zlib_err = 0, zlib_init = 0; 39 int avail, bytes, k = 0, page = 0; 40 41 mutex_lock(&msblk->read_data_mutex); 42 43 msblk->stream.avail_out = 0; 44 msblk->stream.avail_in = 0; 45 46 bytes = length; 47 do { 48 if (msblk->stream.avail_in == 0 && k < b) { 49 avail = min(bytes, msblk->devblksize - offset); 50 bytes -= avail; 51 wait_on_buffer(bh[k]); 52 if (!buffer_uptodate(bh[k])) 53 goto release_mutex; 54 55 if (avail == 0) { 56 offset = 0; 57 put_bh(bh[k++]); 58 continue; 59 } 60 61 msblk->stream.next_in = bh[k]->b_data + offset; 62 msblk->stream.avail_in = avail; 63 offset = 0; 64 } 65 66 if (msblk->stream.avail_out == 0 && page < pages) { 67 msblk->stream.next_out = buffer[page++]; 68 msblk->stream.avail_out = PAGE_CACHE_SIZE; 69 } 70 71 if (!zlib_init) { 72 zlib_err = zlib_inflateInit(&msblk->stream); 73 if (zlib_err != Z_OK) { 74 ERROR("zlib_inflateInit returned unexpected " 75 "result 0x%x, srclength %d\n", 76 zlib_err, srclength); 77 goto release_mutex; 78 } 79 zlib_init = 1; 80 } 81 82 zlib_err = zlib_inflate(&msblk->stream, Z_SYNC_FLUSH); 83 84 if (msblk->stream.avail_in == 0 && k < b) 85 put_bh(bh[k++]); 86 } while (zlib_err == Z_OK); 87 88 if (zlib_err != Z_STREAM_END) { 89 ERROR("zlib_inflate error, data probably corrupt\n"); 90 goto release_mutex; 91 } 92 93 zlib_err = zlib_inflateEnd(&msblk->stream); 94 if (zlib_err != Z_OK) { 95 ERROR("zlib_inflate error, data probably corrupt\n"); 96 goto release_mutex; 97 } 98 99 mutex_unlock(&msblk->read_data_mutex); 100 return msblk->stream.total_out; 101 102 release_mutex: 103 mutex_unlock(&msblk->read_data_mutex); 104 105 for (; k < b; k++) 106 put_bh(bh[k]); 107 108 return -EIO; 109 } 110