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/*
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* jffs2root.c |
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* |
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* Copyright (C) 2005 Mike Baker
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* |
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* $Id$ |
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* |
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* This program is free software; you can redistribute it and/or |
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* modify it under the terms of the GNU General Public License |
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* as published by the Free Software Foundation; either version 2 |
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* of the License, or (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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* 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
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* |
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*/ |
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#include <stdio.h> |
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#include <stdlib.h> |
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#include <stddef.h> |
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#include <unistd.h> |
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#include <fcntl.h> |
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#include <sys/mman.h> |
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#include <sys/stat.h> |
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#include <string.h> |
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#define FILENAME "/dev/mtdblock/1" |
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struct trx_header { |
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unsigned magic; /* "HDR0" */ |
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unsigned len; /* Length of file including header */ |
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unsigned crc32; /* 32-bit CRC from flag_version to end of file */ |
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unsigned flag_version; /* 0:15 flags, 16:31 version */ |
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unsigned offsets[3]; /* Offsets of partitions from start of header */ |
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}; |
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unsigned long *crc32; |
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void init_crc32() |
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{ |
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unsigned long crc; |
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unsigned long poly = 0xEDB88320L; |
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int n, bit; |
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crc32 = (unsigned long *) malloc(256 * sizeof(unsigned long)); |
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for (n = 0; n < 256; n++) { |
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crc = (unsigned long) n; |
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for (bit = 0; bit < 8; bit++) |
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crc = (crc & 1) ? (poly ^ (crc >> 1)) : (crc >> 1); |
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crc32[n] = crc; |
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} |
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} |
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unsigned int crc32buf(char *buf, size_t len) |
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{ |
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unsigned int crc = 0xFFFFFFFF; |
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for (; len; len--, buf++) |
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crc = crc32[(crc ^ *buf) & 0xff] ^ (crc >> 8); |
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return crc; |
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} |
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int main(int argc, char **argv) |
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{ |
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int fd; |
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unsigned long len; |
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struct trx_header *ptr; |
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if (((fd = open(FILENAME, O_RDWR)) < 0) |
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|| ((len = lseek(fd, 0, SEEK_END)) < 0) |
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|| ((ptr = (struct trx_header *) mmap(0, len, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0)) == (void *) (-1)) |
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|| (ptr->magic != 0x30524448)) { |
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printf("Error reading trx info\n"); |
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exit(-1); |
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} |
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if (argc > 1 && !strcmp(argv[1],"--move")) { |
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if (ptr->offsets[1] >= ptr->len) { |
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printf("Partition already moved outside trx\n"); |
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} else if (ptr->offsets[1] & 0x0001ffff) { |
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printf("Partition does not start on a block boundary\n"); |
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} else { |
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init_crc32(); |
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bzero((void *)((int)ptr + ptr->len), (size_t)(len - ptr->len)); |
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ptr->len = ptr->offsets[1]; |
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ptr->crc32 = crc32buf((void *) &(ptr->flag_version), ptr->len - offsetof(struct trx_header, flag_version)); |
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msync(ptr,len,MS_SYNC|MS_INVALIDATE); |
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printf("Partition moved; please reboot\n"); |
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} |
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} else { |
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int x; |
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printf("=== trx ===\n"); |
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printf("mapped: 0x%08x\n", (unsigned)ptr); |
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printf(" magic: 0x%08x\n", ptr->magic); |
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printf(" len: 0x%08x\n", ptr->len); |
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printf(" crc: 0x%08x\n", ptr->crc32); |
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for (x = 0; x < 3; x++) |
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printf(" offset[%d]: 0x%08x\n", x, ptr->offsets[x]); |
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} |
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munmap((void *) ptr, sizeof(struct trx_header)); |
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return 0; |
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} |
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