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/*
* jffs2root.c
*
* Copyright (C) 2005 Mike Baker
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
* $Id$
*
*/
#include <stdio.h>
#include <stdlib.h>
#include <stddef.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <string.h>
#define FILENAME "/dev/mtdblock/1"
struct trx_header {
unsigned magic; /* "HDR0" */
unsigned len; /* Length of file including header */
unsigned crc32; /* 32-bit CRC from flag_version to end of file */
unsigned flag_version; /* 0:15 flags, 16:31 version */
unsigned offsets[3]; /* Offsets of partitions from start of header */
};
unsigned long *crc32;
void init_crc32()
{
unsigned long crc;
unsigned long poly = 0xEDB88320L;
int n, bit;
if ((crc32 = (unsigned long *) malloc(256 * sizeof(unsigned long))) == (void *)-1) {
perror("malloc");
exit(1);
}
for (n = 0; n < 256; n++) {
crc = (unsigned long) n;
for (bit = 0; bit < 8; bit++)
crc = (crc & 1) ? (poly ^ (crc >> 1)) : (crc >> 1);
crc32[n] = crc;
}
}
unsigned int crc32buf(char *buf, size_t len)
{
unsigned int crc = 0xFFFFFFFF;
for (; len; len--, buf++)
crc = crc32[(crc ^ *buf) & 0xff] ^ (crc >> 8);
return crc;
}
int main(int argc, char **argv)
{
int fd;
unsigned long len;
struct trx_header *ptr;
unsigned offset;
if (((fd = open(FILENAME, O_RDWR)) < 0)
|| ((len = lseek(fd, 0, SEEK_END)) < 0)
|| ((ptr = (struct trx_header *) mmap(0, len, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0)) == (void *) (-1))
|| (ptr->magic != 0x30524448)) {
printf("Error reading trx info\n");
exit(-1);
}
/* treat last partition as rootfs offset */
offset = ptr->offsets[2] ? : ptr->offsets[1];
if (argc > 1 && !strcmp(argv[1],"--move")) {
if (offset >= ptr->len) {
printf("Partition already moved outside trx\n");
#if 0
} else if (offset & 0x0001ffff) {
printf("Partition does not start on a block boundary\n");
#endif
} else {
init_crc32();
//bzero((void *)((int)ptr + ptr->len), (size_t)(len - ptr->len));
ptr->len = offset;
ptr->crc32 = crc32buf((void *) &(ptr->flag_version), ptr->len - offsetof(struct trx_header, flag_version));
msync(ptr,sizeof(struct trx_header),MS_SYNC|MS_INVALIDATE);
printf("Partition moved; please reboot\n");
}
} else {
int x;
printf("=== trx ===\n");
printf("mapped: 0x%08x\n", (unsigned)ptr);
printf(" magic: 0x%08x\n", ptr->magic);
printf(" len: 0x%08x\n", ptr->len);
printf(" crc: 0x%08x\n", ptr->crc32);
for (x = 0; x < 3; x++)
printf(" offset[%d]: 0x%08x\n", x, ptr->offsets[x]);
}
munmap((void *) ptr, len);
close (fd);
return 0;
}
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