110 lines
3.5 KiB
C
110 lines
3.5 KiB
C
/*
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* cramfs_common - cramfs common code
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*
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* Copyright (c) 2008 Roy Peled, the.roy.peled -at- gmail.com
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* Copyright (c) 2004-2006 by Juliane Holzt, kju -at- fqdn.org
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*
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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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*
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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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*
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*/
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#include <string.h>
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#include "cramfs.h"
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#include "../include/bitops.h"
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uint32_t u32_toggle_endianness(int big_endian, uint32_t what)
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{
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return big_endian == HOST_IS_BIG_ENDIAN ? what : swab32(what);
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}
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void super_toggle_endianness(int big_endian, struct cramfs_super *super)
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{
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if (big_endian != HOST_IS_BIG_ENDIAN) {
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super->magic = swab32(super->magic);
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super->size = swab32(super->size);
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super->flags = swab32(super->flags);
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super->future = swab32(super->future);
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super->fsid.crc = swab32(super->fsid.crc);
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super->fsid.edition = swab32(super->fsid.edition);
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super->fsid.blocks = swab32(super->fsid.blocks);
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super->fsid.files = swab32(super->fsid.files);
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}
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}
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static void inode_toggle_endianness(int input_big_endian, int output_big_endian,
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struct cramfs_inode *inode_in,
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struct cramfs_inode *inode_out)
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{
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if (input_big_endian == output_big_endian) {
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memmove(inode_out, inode_in, sizeof(*inode_out));
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} else {
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unsigned char inode_out_buf[sizeof(*inode_in)];
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unsigned char *inode_in_buf = (unsigned char*)inode_in;
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inode_out_buf[0] = inode_in_buf[1]; /* 16 bit: mode */
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inode_out_buf[1] = inode_in_buf[0];
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inode_out_buf[2] = inode_in_buf[3]; /* 16 bit: uid */
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inode_out_buf[3] = inode_in_buf[2];
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inode_out_buf[4] = inode_in_buf[6]; /* 24 bit: size */
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inode_out_buf[5] = inode_in_buf[5];
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inode_out_buf[6] = inode_in_buf[4];
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inode_out_buf[7] = inode_in_buf[7]; /* 8 bit: gid width */
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/*
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* Stop the madness! Outlaw C bitfields! They are unportable
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* and nasty! See for yourself what a mess this is:
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*/
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if (output_big_endian) {
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inode_out_buf[ 8] = ( (inode_in_buf[ 8]&0x3F) << 2 ) |
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( (inode_in_buf[11]&0xC0) >> 6 );
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inode_out_buf[ 9] = ( (inode_in_buf[11]&0x3F) << 2 ) |
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( (inode_in_buf[10]&0xC0) >> 6 );
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inode_out_buf[10] = ( (inode_in_buf[10]&0x3F) << 2 ) |
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( (inode_in_buf[ 9]&0xC0) >> 6 );
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inode_out_buf[11] = ( (inode_in_buf[ 9]&0x3F) << 2 ) |
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( (inode_in_buf[ 8]&0xC0) >> 6 );
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} else {
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inode_out_buf[ 8] = ( (inode_in_buf[ 8]&0xFD) >> 2 ) |
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( (inode_in_buf[11]&0x03) << 6 );
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inode_out_buf[ 9] = ( (inode_in_buf[11]&0xFD) >> 2 ) |
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( (inode_in_buf[10]&0x03) << 6 );
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inode_out_buf[10] = ( (inode_in_buf[10]&0xFD) >> 2 ) |
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( (inode_in_buf[ 9]&0x03) << 6 );
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inode_out_buf[11] = ( (inode_in_buf[ 9]&0xFD) >> 2 ) |
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( (inode_in_buf[ 8]&0x03) << 6 );
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}
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memmove(inode_out, inode_out_buf, sizeof(*inode_out));
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}
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}
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void inode_to_host(int from_big_endian, struct cramfs_inode *inode_in,
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struct cramfs_inode *inode_out)
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{
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inode_toggle_endianness(from_big_endian, HOST_IS_BIG_ENDIAN, inode_in,
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inode_out);
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}
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void inode_from_host(int to_big_endian, struct cramfs_inode *inode_in,
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struct cramfs_inode *inode_out)
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{
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inode_toggle_endianness(HOST_IS_BIG_ENDIAN, to_big_endian, inode_in,
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inode_out);
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}
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