openwrt/target/linux/package/openwrt/jffs2root.c

   1 /*
   2  * jffs2root.c
   3  *
   4  * Copyright (C) 2005 Mike Baker
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License
   8  * as published by the Free Software Foundation; either version 2
   9  * of the License, or (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  19  *
  20  * $Id$
  21  *
  22  */
  23
  24 #include <stdio.h>
  25 #include <stdlib.h>
  26 #include <stddef.h>
  27 #include <unistd.h>
  28 #include <fcntl.h>
  29 #include <sys/mman.h>
  30 #include <sys/stat.h>
  31 #include <string.h>
  32
  33 #include <sys/ioctl.h>
  34 #include <linux/mtd/mtd.h>
  35
  36 #define FILENAME "/dev/mtdblock/1"
  37
  38 struct trx_header {
  39     unsigned magic;             /* "HDR0" */
  40     unsigned len;               /* Length of file including header */
  41     unsigned crc32;             /* 32-bit CRC from flag_version to end of file */
  42     unsigned flag_version;      /* 0:15 flags, 16:31 version */
  43     unsigned offsets[3];        /* Offsets of partitions from start of header */
  44 };
  45
  46 unsigned long *crc32;
  47
  48 void init_crc32()
  49 {
  50     unsigned long crc;
  51     unsigned long poly = 0xEDB88320L;
  52     int n, bit;
  53     if ((crc32 = (unsigned long *) malloc(256 * sizeof(unsigned long))) == (void *)-1) {
  54             perror("malloc");
  55             exit(1);
  56     }
  57     for (n = 0; n < 256; n++) {
  58         crc = (unsigned long) n;
  59         for (bit = 0; bit < 8; bit++)
  60             crc = (crc & 1) ? (poly ^ (crc >> 1)) : (crc >> 1);
  61         crc32[n] = crc;
  62     }
  63 }
  64
  65 unsigned int crc32buf(char *buf, size_t len)
  66 {
  67     unsigned int crc = 0xFFFFFFFF;
  68     for (; len; len--, buf++)
  69         crc = crc32[(crc ^ *buf) & 0xff] ^ (crc >> 8);
  70     return crc;
  71 }
  72
  73 int main(int argc, char **argv)
  74 {
  75     int fd;
  76     struct mtd_info_user mtdInfo;
  77     unsigned long len;
  78     struct trx_header *ptr;
  79
  80     if (((fd = open(FILENAME, O_RDWR))  < 0)
  81     || ((len = lseek(fd, 0, SEEK_END)) < 0)
  82     || ((ptr = (struct trx_header *) mmap(0, len, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0)) == (void *) (-1))
  83     || (ptr->magic != 0x30524448)) {
  84         printf("Error reading trx info\n");
  85         exit(-1);
  86     }
  87     close (fd);
  88
  89     if (((fd = open("/dev/mtd/1", O_RDWR))  < 0)
  90     || (ioctl(fd, MEMGETINFO, &mtdInfo))) {
  91       fprintf(stderr, "Could not get MTD device info from %s\n", FILENAME);
  92       close(fd);
  93       exit(1);
  94     }
  95     close(fd);
  96
  97     if (argc > 1 && !strcmp(argv[1],"--move")) {
  98       if (ptr->offsets[2] >= ptr->len) {
  99         printf("Partition already moved outside trx\n");
 100       } else {
 101         init_crc32();
 102         ptr->offsets[2] +=  (mtdInfo.erasesize - 1);
 103         ptr->offsets[2] &= ~(mtdInfo.erasesize - 1);
 104         ptr->len = ptr->offsets[2];
 105         ptr->crc32 = crc32buf((void *) &(ptr->flag_version), ptr->len - offsetof(struct trx_header, flag_version));
 106         msync(ptr,sizeof(struct trx_header),MS_SYNC|MS_INVALIDATE);
 107         printf("Partition moved; please reboot\n");
 108       }
 109     } else {
 110       int x;
 111       printf(" erase: 0x%08x\n",mtdInfo.erasesize);
 112       printf("=== trx ===\n");
 113       printf("mapped: 0x%08x\n", (unsigned)ptr);
 114       printf(" magic: 0x%08x\n", ptr->magic);
 115       printf("   len: 0x%08x\n", ptr->len);
 116       printf("   crc: 0x%08x\n", ptr->crc32);
 117       for (x = 0; x < 3; x++)
 118         printf(" offset[%d]: 0x%08x\n", x, ptr->offsets[x]);
 119     }
 120
 121     munmap((void *) ptr, len);
 122     return 0;
 123 }