package/base-files/src/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         char *buf;
  80
  81         if (((fd = open(FILENAME, O_RDWR))      < 0)
  82                         || ((len = lseek(fd, 0, SEEK_END)) < 0)
  83                         || ((ptr = (struct trx_header *) mmap(0, len, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0)) == (void *) (-1))
  84                         || (ptr->magic != 0x30524448)) {
  85                 printf("Error reading trx info\n");
  86                 exit(-1);
  87         }
  88         close (fd);
  89
  90         if (((fd = open("/dev/mtd/1", O_RDWR))  < 0)
  91                         || (ioctl(fd, MEMGETINFO, &mtdInfo))) {
  92                 fprintf(stderr, "Could not get MTD device info from %s\n", FILENAME);
  93                 close(fd);
  94                 exit(1);
  95         }
  96         close(fd);
  97
  98         if (argc > 1 && !strcmp(argv[1],"--move")) {
  99                 if (ptr->offsets[2] >= ptr->len) {
 100                         printf("Partition already moved outside trx\n");
 101                 } else {
 102                         init_crc32();
 103                         ptr->offsets[2] +=      (mtdInfo.erasesize - 1);
 104                         ptr->offsets[2] &= ~(mtdInfo.erasesize - 1);
 105                         ptr->len = ptr->offsets[2];
 106                         ptr->crc32 = crc32buf((void *) &(ptr->flag_version), ptr->len - offsetof(struct trx_header, flag_version));
 107                         msync(ptr,sizeof(struct trx_header),MS_SYNC|MS_INVALIDATE);
 108                         printf("Partition moved; please reboot\n");
 109                 }
 110         } else if (argc > 1 && !strcmp(argv[1], "--clean")) {
 111                 buf = (char *) ptr;
 112                 if (buf[ptr->offsets[1] - 1] == 0) {
 113                         init_crc32();
 114                         buf[ptr->offsets[1] - 1] = 1;
 115                         ptr->crc32 = crc32buf((void *) &(ptr->flag_version), ptr->len - offsetof(struct trx_header, flag_version));
 116                         msync(ptr,sizeof(struct trx_header),MS_SYNC|MS_INVALIDATE);
 117                         printf("Partition marked as clean\n");
 118                 }
 119         } else {
 120                 int x;
 121                 printf(" erase: 0x%08x\n",mtdInfo.erasesize);
 122                 printf("=== trx ===\n");
 123                 printf("mapped: 0x%08x\n", (unsigned)ptr);
 124                 printf(" magic: 0x%08x\n", ptr->magic);
 125                 printf("         len: 0x%08x\n", ptr->len);
 126                 printf("         crc: 0x%08x\n", ptr->crc32);
 127                 for (x = 0; x < 3; x++)
 128                         printf(" offset[%d]: 0x%08x\n", x, ptr->offsets[x]);
 129         }
 130
 131         munmap((void *) ptr, len);
 132         return 0;
 133 }