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/* ext2.c - Second Extended filesystem */
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* GRUB -- GRand Unified Bootloader
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* Copyright (C) 2003, 2004, 2005 Free Software Foundation, Inc.
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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/* Magic value used to identify an ext2 filesystem. */
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#define EXT2_MAGIC 0xEF53
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/* Amount of indirect blocks in an inode. */
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#define INDIRECT_BLOCKS 12
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/* Maximum lenght of a pathname. */
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#define EXT2_PATH_MAX 4096
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/* Maximum nesting of symlinks, used to prevent a loop. */
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#define EXT2_MAX_SYMLINKCNT 8
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/* Filetype used in directory entry. */
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#define FILETYPE_UNKNOWN 0
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#define FILETYPE_REG 1
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#define FILETYPE_DIRECTORY 2
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#define FILETYPE_SYMLINK 7
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/* Filetype information as used in inodes. */
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#define FILETYPE_INO_MASK 0170000
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#define FILETYPE_INO_REG 0100000
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#define FILETYPE_INO_DIRECTORY 0040000
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#define FILETYPE_INO_SYMLINK 0120000
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#include <grub/file.h>
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#include <grub/misc.h>
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#include <grub/disk.h>
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#include <grub/types.h>
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#include <grub/fshelp.h>
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/* Log2 size of ext2 block in 512 blocks. */
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#define LOG2_EXT2_BLOCK_SIZE(data) \
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(grub_le_to_cpu32 (data->sblock.log2_block_size) + 1)
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/* Log2 size of ext2 block in bytes. */
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#define LOG2_BLOCK_SIZE(data) \
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(grub_le_to_cpu32 (data->sblock.log2_block_size) + 10)
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/* The size of an ext2 block in bytes. */
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#define EXT2_BLOCK_SIZE(data) (1 << LOG2_BLOCK_SIZE(data))
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/* The ext2 superblock. */
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struct grub_ext2_sblock
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grub_uint32_t total_inodes;
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grub_uint32_t total_blocks;
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grub_uint32_t reserved_blocks;
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grub_uint32_t free_blocks;
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grub_uint32_t free_inodes;
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grub_uint32_t first_data_block;
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grub_uint32_t log2_block_size;
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grub_uint32_t log2_fragment_size;
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grub_uint32_t blocks_per_group;
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grub_uint32_t fragments_per_group;
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grub_uint32_t inodes_per_group;
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grub_uint16_t mnt_count;
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grub_uint16_t max_mnt_count;
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grub_uint16_t fs_state;
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grub_uint16_t error_handling;
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grub_uint16_t minor_revision_level;
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grub_uint32_t lastcheck;
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grub_uint32_t checkinterval;
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grub_uint32_t creator_os;
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grub_uint32_t revision_level;
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grub_uint16_t uid_reserved;
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grub_uint16_t gid_reserved;
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grub_uint32_t first_inode;
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grub_uint16_t inode_size;
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grub_uint16_t block_group_number;
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grub_uint32_t feature_compatibility;
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grub_uint32_t feature_incompat;
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grub_uint32_t feature_ro_compat;
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grub_uint32_t unique_id[4];
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char last_mounted_on[64];
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grub_uint32_t compression_info;
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/* The ext2 blockgroup. */
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struct grub_ext2_block_group
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grub_uint32_t block_id;
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grub_uint32_t inode_id;
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grub_uint32_t inode_table_id;
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grub_uint16_t free_blocks;
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grub_uint16_t free_inodes;
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grub_uint32_t reserved[3];
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/* The ext2 inode. */
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struct grub_ext2_inode
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grub_uint16_t nlinks;
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grub_uint32_t blockcnt; /* Blocks of 512 bytes!! */
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grub_uint32_t dir_blocks[INDIRECT_BLOCKS];
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grub_uint32_t indir_block;
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grub_uint32_t double_indir_block;
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grub_uint32_t tripple_indir_block;
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grub_uint32_t version;
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grub_uint32_t dir_acl;
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grub_uint32_t fragment_addr;
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grub_uint32_t osd2[3];
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/* The header of an ext2 directory entry. */
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grub_uint16_t direntlen;
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grub_uint8_t namelen;
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grub_uint8_t filetype;
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struct grub_fshelp_node
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struct grub_ext2_data *data;
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struct grub_ext2_inode inode;
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/* Information about a "mounted" ext2 filesystem. */
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struct grub_ext2_data
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struct grub_ext2_sblock sblock;
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struct grub_ext2_inode *inode;
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struct grub_fshelp_node diropen;
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static grub_dl_t my_mod;
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/* Read into BLKGRP the blockgroup descriptor of blockgroup GROUP of
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the mounted filesystem DATA. */
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inline static grub_err_t
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grub_ext2_blockgroup (struct grub_ext2_data *data, int group,
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struct grub_ext2_block_group *blkgrp)
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return grub_disk_read (data->disk,
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((grub_le_to_cpu32 (data->sblock.first_data_block) + 1)
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<< LOG2_EXT2_BLOCK_SIZE (data)),
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group * sizeof (struct grub_ext2_block_group),
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sizeof (struct grub_ext2_block_group), (char *) blkgrp);
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grub_ext2_read_block (grub_fshelp_node_t node, int fileblock)
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struct grub_ext2_data *data = node->data;
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struct grub_ext2_inode *inode = &node->inode;
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int blksz = EXT2_BLOCK_SIZE (data);
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int log2_blksz = LOG2_EXT2_BLOCK_SIZE (data);
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if (fileblock < INDIRECT_BLOCKS)
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blknr = grub_le_to_cpu32 (inode->blocks.dir_blocks[fileblock]);
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else if (fileblock < INDIRECT_BLOCKS + blksz / 4)
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grub_uint32_t indir[blksz / 4];
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if (grub_disk_read (data->disk,
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grub_le_to_cpu32 (inode->blocks.indir_block)
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0, blksz, (char *) indir))
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blknr = grub_le_to_cpu32 (indir[fileblock - INDIRECT_BLOCKS]);
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/* Double indirect. */
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else if (fileblock < INDIRECT_BLOCKS + blksz / 4 * (blksz / 4 + 1))
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unsigned int perblock = blksz / 4;
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unsigned int rblock = fileblock - (INDIRECT_BLOCKS
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grub_uint32_t indir[blksz / 4];
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if (grub_disk_read (data->disk,
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grub_le_to_cpu32 (inode->blocks.double_indir_block)
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0, blksz, (char *) indir))
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if (grub_disk_read (data->disk,
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grub_le_to_cpu32 (indir[rblock / perblock])
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0, blksz, (char *) indir))
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blknr = grub_le_to_cpu32 (indir[rblock % perblock]);
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/* Tripple indirect. */
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grub_error (GRUB_ERR_NOT_IMPLEMENTED_YET,
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"ext2fs doesn't support tripple indirect blocks");
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/* Read LEN bytes from the file described by DATA starting with byte
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POS. Return the amount of read bytes in READ. */
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grub_ext2_read_file (grub_fshelp_node_t node,
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void (*read_hook) (unsigned long sector,
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unsigned offset, unsigned length),
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int pos, unsigned int len, char *buf)
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return grub_fshelp_read_file (node->data->disk, node, read_hook,
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pos, len, buf, grub_ext2_read_block,
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LOG2_EXT2_BLOCK_SIZE (node->data));
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/* Read the inode INO for the file described by DATA into INODE. */
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grub_ext2_read_inode (struct grub_ext2_data *data,
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int ino, struct grub_ext2_inode *inode)
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struct grub_ext2_block_group blkgrp;
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struct grub_ext2_sblock *sblock = &data->sblock;
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int inodes_per_block;
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/* It is easier to calculate if the first inode is 0. */
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grub_ext2_blockgroup (data, ino / grub_le_to_cpu32 (sblock->inodes_per_group),
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inodes_per_block = EXT2_BLOCK_SIZE (data) / 128;
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blkno = (ino % grub_le_to_cpu32 (sblock->inodes_per_group))
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blkoff = (ino % grub_le_to_cpu32 (sblock->inodes_per_group))
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/* Read the inode. */
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if (grub_disk_read (data->disk,
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((grub_le_to_cpu32 (blkgrp.inode_table_id) + blkno)
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<< LOG2_EXT2_BLOCK_SIZE (data)),
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sizeof (struct grub_ext2_inode) * blkoff,
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sizeof (struct grub_ext2_inode), (char *) inode))
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static struct grub_ext2_data *
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grub_ext2_mount (grub_disk_t disk)
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struct grub_ext2_data *data;
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data = grub_malloc (sizeof (struct grub_ext2_data));
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/* Read the superblock. */
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grub_disk_read (disk, 1 * 2, 0, sizeof (struct grub_ext2_sblock),
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(char *) &data->sblock);
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/* Make sure this is an ext2 filesystem. */
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if (grub_le_to_cpu16 (data->sblock.magic) != EXT2_MAGIC)
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data->diropen.data = data;
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data->diropen.ino = 2;
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data->diropen.inode_read = 1;
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data->inode = &data->diropen.inode;
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grub_ext2_read_inode (data, 2, data->inode);
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grub_error (GRUB_ERR_BAD_FS, "not an ext2 filesystem");
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grub_ext2_read_symlink (grub_fshelp_node_t node)
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struct grub_fshelp_node *diro = node;
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if (!diro->inode_read)
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grub_ext2_read_inode (diro->data, diro->ino, &diro->inode);
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symlink = grub_malloc (grub_le_to_cpu32 (diro->inode.size) + 1);
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/* If the filesize of the symlink is bigger than
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60 the symlink is stored in a separate block,
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otherwise it is stored in the inode. */
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if (grub_le_to_cpu32 (diro->inode.size) <= 60)
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grub_strncpy (symlink,
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grub_le_to_cpu32 (diro->inode.size));
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grub_ext2_read_file (diro, 0, 0,
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grub_le_to_cpu32 (diro->inode.size),
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symlink[grub_le_to_cpu32 (diro->inode.size)] = '\0';
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grub_ext2_iterate_dir (grub_fshelp_node_t dir,
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(*hook) (const char *filename,
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enum grub_fshelp_filetype filetype,
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grub_fshelp_node_t node))
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unsigned int fpos = 0;
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struct grub_fshelp_node *diro = (struct grub_fshelp_node *) dir;
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if (!diro->inode_read)
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grub_ext2_read_inode (diro->data, diro->ino, &diro->inode);
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/* Search the file. */
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while (fpos < grub_le_to_cpu32 (diro->inode.size))
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struct ext2_dirent dirent;
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grub_ext2_read_file (diro, 0, fpos, sizeof (struct ext2_dirent),
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if (dirent.namelen != 0)
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char filename[dirent.namelen + 1];
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struct grub_fshelp_node *fdiro;
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enum grub_fshelp_filetype type = GRUB_FSHELP_UNKNOWN;
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grub_ext2_read_file (diro, 0, fpos + sizeof (struct ext2_dirent),
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dirent.namelen, filename);
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fdiro = grub_malloc (sizeof (struct grub_fshelp_node));
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fdiro->data = diro->data;
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fdiro->ino = grub_le_to_cpu32 (dirent.inode);
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filename[dirent.namelen] = '\0';
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if (dirent.filetype != FILETYPE_UNKNOWN)
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fdiro->inode_read = 0;
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if (dirent.filetype == FILETYPE_DIRECTORY)
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type = GRUB_FSHELP_DIR;
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else if (dirent.filetype == FILETYPE_SYMLINK)
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type = GRUB_FSHELP_SYMLINK;
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else if (dirent.filetype == FILETYPE_REG)
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type = GRUB_FSHELP_REG;
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/* The filetype can not be read from the dirent, read
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the inode to get more information. */
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grub_ext2_read_inode (diro->data, grub_le_to_cpu32 (dirent.inode),
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fdiro->inode_read = 1;
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if ((grub_le_to_cpu16 (fdiro->inode.mode)
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& FILETYPE_INO_MASK) == FILETYPE_INO_DIRECTORY)
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type = GRUB_FSHELP_DIR;
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else if ((grub_le_to_cpu16 (fdiro->inode.mode)
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& FILETYPE_INO_MASK) == FILETYPE_INO_SYMLINK)
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type = GRUB_FSHELP_SYMLINK;
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else if ((grub_le_to_cpu16 (fdiro->inode.mode)
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& FILETYPE_INO_MASK) == FILETYPE_INO_REG)
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type = GRUB_FSHELP_REG;
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if (hook (filename, type, fdiro))
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fpos += grub_le_to_cpu16 (dirent.direntlen);
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/* Open a file named NAME and initialize FILE. */
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grub_ext2_open (struct grub_file *file, const char *name)
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struct grub_ext2_data *data;
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struct grub_fshelp_node *fdiro = 0;
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grub_dl_ref (my_mod);
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data = grub_ext2_mount (file->device->disk);
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grub_fshelp_find_file (name, &data->diropen, &fdiro, grub_ext2_iterate_dir,
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grub_ext2_read_symlink, GRUB_FSHELP_REG);
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if (!fdiro->inode_read)
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grub_ext2_read_inode (data, fdiro->ino, &fdiro->inode);
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grub_memcpy (data->inode, &fdiro->inode, sizeof (struct grub_ext2_inode));
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file->size = grub_le_to_cpu32 (data->inode->size);
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if (fdiro != &data->diropen)
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grub_dl_unref (my_mod);
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grub_ext2_close (grub_file_t file)
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grub_free (file->data);
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grub_dl_unref (my_mod);
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return GRUB_ERR_NONE;
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/* Read LEN bytes data from FILE into BUF. */
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grub_ext2_read (grub_file_t file, char *buf, grub_ssize_t len)
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struct grub_ext2_data *data =
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(struct grub_ext2_data *) file->data;
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return grub_ext2_read_file (&data->diropen, file->read_hook,
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file->offset, len, buf);
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grub_ext2_dir (grub_device_t device, const char *path,
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int (*hook) (const char *filename, int dir))
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struct grub_ext2_data *data = 0;;
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struct grub_fshelp_node *fdiro = 0;
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auto int NESTED_FUNC_ATTR iterate (const char *filename,
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enum grub_fshelp_filetype filetype,
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grub_fshelp_node_t node);
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int NESTED_FUNC_ATTR iterate (const char *filename,
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enum grub_fshelp_filetype filetype,
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grub_fshelp_node_t node)
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if (filetype == GRUB_FSHELP_DIR)
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return hook (filename, 1);
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return hook (filename, 0);
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grub_dl_ref (my_mod);
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data = grub_ext2_mount (device->disk);
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grub_fshelp_find_file (path, &data->diropen, &fdiro, grub_ext2_iterate_dir,
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grub_ext2_read_symlink, GRUB_FSHELP_DIR);
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grub_ext2_iterate_dir (fdiro, iterate);
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if (fdiro != &data->diropen)
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grub_dl_unref (my_mod);
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grub_ext2_label (grub_device_t device, char **label)
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struct grub_ext2_data *data;
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grub_disk_t disk = device->disk;
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grub_dl_ref (my_mod);
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data = grub_ext2_mount (disk);
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*label = grub_strndup (data->sblock.volume_name, 14);
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grub_dl_unref (my_mod);
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static struct grub_fs grub_ext2_fs =
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.dir = grub_ext2_dir,
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.open = grub_ext2_open,
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.read = grub_ext2_read,
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.close = grub_ext2_close,
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.label = grub_ext2_label,
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grub_fs_register (&grub_ext2_fs);
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grub_fs_unregister (&grub_ext2_fs);
added
removed
fs/ext2.c
