source: freewrt/package/jffs2root/jffs2root.c@ 7742579

/*
 * 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: jffs2root.c 3221 2006-02-12 06:00:38Z nbd $
 *
 */

#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>

#include <sys/ioctl.h>
#include <sys/syscall.h>
#include <linux/mtd/mtd.h>
#include <linux/reboot.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;
        struct mtd_info_user mtdInfo;
        unsigned long len;
        struct trx_header *ptr;
        char *buf;
        int reboot;

        reboot = 0;
        
        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);
        }
        close (fd);

        if (((fd = open("/dev/mtd/1", O_RDWR))  < 0)
                        || (ioctl(fd, MEMGETINFO, &mtdInfo))) {
                fprintf(stderr, "Could not get MTD device info from %s\n", FILENAME);
                close(fd);
                exit(1);
        }
        close(fd);

        if (argc > 1 && !strcmp(argv[1],"--move")) {
                if (ptr->offsets[2] >= ptr->len) {
                        printf("Partition already moved outside trx\n");
                } else {
                        init_crc32();
                        ptr->offsets[2] +=      (mtdInfo.erasesize - 1);
                        ptr->offsets[2] &= ~(mtdInfo.erasesize - 1);
                        ptr->len = ptr->offsets[2];
                        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);
                        if (argc > 2 && !strcmp(argv[2],"--reboot")) {
                                reboot=1;
                                printf("Partition moved.\n");
                        } else {
                                printf("Partition moved; please reboot\n");
                        }
                }
        } else if (argc > 1 && !strcmp(argv[1], "--clean")) {
                buf = (char *) ptr;
                if (buf[ptr->offsets[1] - 1] == 0) {
                        init_crc32();
                        buf[ptr->offsets[1] - 1] = 1;
                        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 marked as clean\n");
                }
        } else {
                int x;
                printf(" erase: 0x%08x\n",mtdInfo.erasesize);
                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);
        if (reboot) {
                fflush(stdout);
                syscall(SYS_reboot,LINUX_REBOOT_MAGIC1,LINUX_REBOOT_MAGIC2,LINUX_REBOOT_CMD_RESTART,NULL);
        }
        return 0;
}