~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

TOMOYO Linux Cross Reference
Linux/fs/squashfs/fragment.c

Version: ~ [ linux-5.6 ] ~ [ linux-5.5.13 ] ~ [ linux-5.4.28 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.113 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.174 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.217 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.217 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.140 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.82 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-3.9.11 ] ~ [ linux-3.8.13 ] ~ [ linux-3.7.10 ] ~ [ linux-3.6.11 ] ~ [ linux-3.5.7 ] ~ [ linux-3.4.113 ] ~ [ linux-3.3.8 ] ~ [ linux-3.2.102 ] ~ [ linux-3.1.10 ] ~ [ linux-3.0.101 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  1 /*
  2  * Squashfs - a compressed read only filesystem for Linux
  3  *
  4  * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008
  5  * Phillip Lougher <phillip@squashfs.org.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  * fragment.c
 22  */
 23 
 24 /*
 25  * This file implements code to handle compressed fragments (tail-end packed
 26  * datablocks).
 27  *
 28  * Regular files contain a fragment index which is mapped to a fragment
 29  * location on disk and compressed size using a fragment lookup table.
 30  * Like everything in Squashfs this fragment lookup table is itself stored
 31  * compressed into metadata blocks.  A second index table is used to locate
 32  * these.  This second index table for speed of access (and because it
 33  * is small) is read at mount time and cached in memory.
 34  */
 35 
 36 #include <linux/fs.h>
 37 #include <linux/vfs.h>
 38 #include <linux/slab.h>
 39 
 40 #include "squashfs_fs.h"
 41 #include "squashfs_fs_sb.h"
 42 #include "squashfs.h"
 43 
 44 /*
 45  * Look-up fragment using the fragment index table.  Return the on disk
 46  * location of the fragment and its compressed size
 47  */
 48 int squashfs_frag_lookup(struct super_block *sb, unsigned int fragment,
 49                                 u64 *fragment_block)
 50 {
 51         struct squashfs_sb_info *msblk = sb->s_fs_info;
 52         int block = SQUASHFS_FRAGMENT_INDEX(fragment);
 53         int offset = SQUASHFS_FRAGMENT_INDEX_OFFSET(fragment);
 54         u64 start_block = le64_to_cpu(msblk->fragment_index[block]);
 55         struct squashfs_fragment_entry fragment_entry;
 56         int size;
 57 
 58         size = squashfs_read_metadata(sb, &fragment_entry, &start_block,
 59                                         &offset, sizeof(fragment_entry));
 60         if (size < 0)
 61                 return size;
 62 
 63         *fragment_block = le64_to_cpu(fragment_entry.start_block);
 64         size = le32_to_cpu(fragment_entry.size);
 65 
 66         return size;
 67 }
 68 
 69 
 70 /*
 71  * Read the uncompressed fragment lookup table indexes off disk into memory
 72  */
 73 __le64 *squashfs_read_fragment_index_table(struct super_block *sb,
 74         u64 fragment_table_start, u64 next_table, unsigned int fragments)
 75 {
 76         unsigned int length = SQUASHFS_FRAGMENT_INDEX_BYTES(fragments);
 77         __le64 *table;
 78 
 79         /*
 80          * Sanity check, length bytes should not extend into the next table -
 81          * this check also traps instances where fragment_table_start is
 82          * incorrectly larger than the next table start
 83          */
 84         if (fragment_table_start + length > next_table)
 85                 return ERR_PTR(-EINVAL);
 86 
 87         table = squashfs_read_table(sb, fragment_table_start, length);
 88 
 89         /*
 90          * table[0] points to the first fragment table metadata block, this
 91          * should be less than fragment_table_start
 92          */
 93         if (!IS_ERR(table) && le64_to_cpu(table[0]) >= fragment_table_start) {
 94                 kfree(table);
 95                 return ERR_PTR(-EINVAL);
 96         }
 97 
 98         return table;
 99 }
100 

~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

kernel.org | git.kernel.org | LWN.net | Project Home | Wiki (Japanese) | Wiki (English) | SVN repository | Mail admin

Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.

osdn.jp