package/system/mtd/src/seama.c

   1 /*
   2  * seama.c
   3  *
   4  * Copyright (C) 2011-2012 Gabor Juhos <juhosg@openwrt.org>
   5  *
   6  * Based on the trx fixup code:
   7  *   Copyright (C) 2005 Mike Baker
   8  *   Copyright (C) 2008 Felix Fietkau <nbd@openwrt.org>
   9  *
  10  * This program is free software; you can redistribute it and/or
  11  * modify it under the terms of the GNU General Public License
  12  * as published by the Free Software Foundation; either version 2
  13  * of the License, or (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  * GNU General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program; if not, write to the Free Software
  22  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  23  */
  24
  25 #include <stdio.h>
  26 #include <stdlib.h>
  27 #include <stddef.h>
  28 #include <unistd.h>
  29 #include <fcntl.h>
  30 #include <sys/mman.h>
  31 #include <sys/stat.h>
  32 #include <string.h>
  33 #include <errno.h>
  34 #include <arpa/inet.h>
  35
  36 #include <sys/ioctl.h>
  37 #include <mtd/mtd-user.h>
  38 #include "mtd.h"
  39 #include "seama.h"
  40 #include "md5.h"
  41
  42 #if __BYTE_ORDER == __BIG_ENDIAN
  43 #define STORE32_LE(X)           ((((X) & 0x000000FF) << 24) | (((X) & 0x0000FF00) << 8) | (((X) & 0x00FF0000) >> 8) | (((X) & 0xFF000000) >> 24))
  44 #elif __BYTE_ORDER == __LITTLE_ENDIAN
  45 #define STORE32_LE(X)           (X)
  46 #else
  47 #error unknown endianness!
  48 #endif
  49
  50 ssize_t pread(int fd, void *buf, size_t count, off_t offset);
  51 ssize_t pwrite(int fd, const void *buf, size_t count, off_t offset);
  52
  53 int
  54 seama_fix_md5(char *buf, size_t len)
  55 {
  56         struct seama_entity_header *shdr = (struct seama_entity_header *) buf;
  57         char *data;
  58         size_t msize;
  59         size_t isize;
  60         MD5_CTX ctx;
  61         unsigned char digest[16];
  62         int i;
  63
  64         if (len < sizeof(struct seama_entity_header))
  65                 return -1;
  66
  67         isize = ntohl(shdr->size);
  68         msize = ntohs(shdr->metasize);
  69         if (isize == 0) {
  70                 /* the image contains no checksum */
  71                 return -1;
  72         }
  73
  74         len -= sizeof(struct seama_entity_header) + msize;
  75         if (isize > len)
  76                 isize = len;
  77
  78         data = buf + sizeof(struct seama_entity_header) + msize;
  79
  80         MD5_Init(&ctx);
  81         MD5_Update(&ctx, data, isize);
  82         MD5_Final(digest, &ctx);
  83
  84         if (!memcmp(digest, shdr->md5, sizeof(digest))) {
  85                 if (quiet < 2)
  86                         fprintf(stderr, "the header is fixed already\n");
  87                 return -1;
  88         }
  89
  90         if (quiet < 2) {
  91                 fprintf(stderr, "new size:%u, new MD5: ", isize);
  92                 for (i = 0; i < sizeof(digest); i++)
  93                         fprintf(stderr, "%02x", digest[i]);
  94
  95                 fprintf(stderr, "\n");
  96         }
  97
  98         /* update the size in the image */
  99         shdr->size = htonl(isize);
 100
 101         /* update the checksum in the image */
 102         memcpy(shdr->md5, digest, sizeof(digest));
 103
 104         return 0;
 105 }
 106
 107 int
 108 mtd_fixseama(const char *mtd, size_t offset)
 109 {
 110         int fd;
 111         char *first_block;
 112         char *buf;
 113         ssize_t res;
 114         size_t block_offset;
 115         struct seama_entity_header *shdr;
 116
 117         if (quiet < 2)
 118                 fprintf(stderr, "Trying to fix SEAMA header in %s at 0x%x...\n",
 119                         mtd, offset);
 120
 121         block_offset = offset & ~(erasesize - 1);
 122         offset -= block_offset;
 123
 124         fd = mtd_check_open(mtd);
 125         if(fd < 0) {
 126                 fprintf(stderr, "Could not open mtd device: %s\n", mtd);
 127                 exit(1);
 128         }
 129
 130         if (block_offset + erasesize > mtdsize) {
 131                 fprintf(stderr, "Offset too large, device size 0x%x\n",
 132                         mtdsize);
 133                 exit(1);
 134         }
 135
 136         first_block = malloc(erasesize);
 137         if (!first_block) {
 138                 perror("malloc");
 139                 exit(1);
 140         }
 141
 142         res = pread(fd, first_block, erasesize, block_offset);
 143         if (res != erasesize) {
 144                 perror("pread");
 145                 exit(1);
 146         }
 147
 148         shdr = (struct seama_entity_header *)first_block;
 149         if (shdr->magic != htonl(SEAMA_MAGIC)) {
 150                 fprintf(stderr, "No SEAMA header found\n");
 151                 return -1;
 152         }
 153
 154         buf = malloc(mtdsize);
 155         if (!buf) {
 156                 perror("malloc");
 157                 exit(1);
 158         }
 159
 160         res = pread(fd, buf, mtdsize, block_offset);
 161         if (res != mtdsize) {
 162                 perror("pread");
 163                 exit(1);
 164         }
 165
 166         if (seama_fix_md5(buf, mtdsize))
 167                 goto out;
 168
 169         if (mtd_erase_block(fd, block_offset)) {
 170                 fprintf(stderr, "Can't erease block at 0x%x (%s)\n",
 171                         block_offset, strerror(errno));
 172                 exit(1);
 173         }
 174
 175         if (quiet < 2)
 176                 fprintf(stderr, "Rewriting block at 0x%x\n", block_offset);
 177
 178         if (pwrite(fd, buf, erasesize, block_offset) != erasesize) {
 179                 fprintf(stderr, "Error writing block (%s)\n", strerror(errno));
 180                 exit(1);
 181         }
 182
 183         if (quiet < 2)
 184                 fprintf(stderr, "Done.\n");
 185
 186 out:
 187         close (fd);
 188         sync();
 189
 190         return 0;
 191 }
 192