86 lines
2.6 KiB
C
86 lines
2.6 KiB
C
/*
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File: fat_common.c
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Copyright (C) 1998-2009 Christophe GRENIER <grenier@cgsecurity.org>
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This software 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 along
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with this program; if not, write the Free Software Foundation, Inc., 51
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Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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#ifdef HAVE_CONFIG_H
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#include <config.h>
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#endif
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#ifdef HAVE_STRING_H
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#include <string.h>
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#endif
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#include "types.h"
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#include "common.h"
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#include "fat_common.h"
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unsigned int fat_sector_size(const struct fat_boot_sector *fat_header)
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{
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const unsigned int hi=fat_header->sector_size[1];
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const unsigned int lo=fat_header->sector_size[0];
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/*@ assert 0 <= hi < 1<<8; */
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/*@ assert 0 <= hi<<8 < 1<<16; */
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/*@ assert 0 <= lo < 1<<8; */
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const unsigned int res=(hi<<8)|lo;
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/*@ assert res <= 65535; */
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return res;
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}
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unsigned int get_dir_entries(const struct fat_boot_sector *fat_header)
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{
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const unsigned int hi=fat_header->dir_entries[1];
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const unsigned int lo=fat_header->dir_entries[0];
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/*@ assert 0 <= hi < 1<<8; */
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/*@ assert 0 <= hi<<8 < 1<<16; */
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/*@ assert 0 <= lo < 1<<8; */
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const unsigned int res=(hi<<8)|lo;
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/*@ assert res <= 65535; */
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return res;
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}
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unsigned int fat_sectors(const struct fat_boot_sector *fat_header)
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{
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const unsigned int hi=fat_header->sectors[1];
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const unsigned int lo=fat_header->sectors[0];
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/*@ assert 0 <= hi < 1<<8; */
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/*@ assert 0 <= hi<<8 < 1<<16; */
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/*@ assert 0 <= lo < 1<<8; */
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const unsigned int res=(hi<<8)|lo;
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/*@ assert res <= 65535; */
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return res;
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}
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unsigned int fat_get_cluster_from_entry(const struct msdos_dir_entry *entry)
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{
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const unsigned int hi=le16(entry->starthi);
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const unsigned int lo=le16(entry->start);
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/*@ assert 0 <= hi < 1<<16; */
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/*@ assert 0 <= hi<<16 < 1<<32; */
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/*@ assert 0 <= lo < 1<<16; */
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return (hi<<16) | lo;
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}
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int is_fat_directory(const unsigned char *buffer)
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{
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return(buffer[0]=='.' &&
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memcmp(buffer, ". ", 8+3)==0 &&
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memcmp(&buffer[0x20], ".. ", 8+3)==0 &&
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buffer[0xB]!=ATTR_EXT && (buffer[0xB]&ATTR_DIR)!=0 &&
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buffer[1*0x20+0xB]!=ATTR_EXT && (buffer[1*0x20+0xB]&ATTR_DIR)!=0);
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}
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