package/mtd/src/imagetag.c

   1 /*
   2  * imagetag.c
   3  *
   4  * Copyright (C) 2005 Mike Baker
   5  * Copyright (C) 2008 Felix Fietkau <nbd@openwrt.org>
   6  * Copyrigth (C) 2010 Daniel Dickinson <openwrt@cshore.neomailbox.net>
   7  *
   8  * This program is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU General Public License
  10  * as published by the Free Software Foundation; either version 2
  11  * of the License, or (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  21  */
  22
  23 #include <stdio.h>
  24 #include <stdlib.h>
  25 #include <stddef.h>
  26 #include <unistd.h>
  27 #include <fcntl.h>
  28 #include <sys/mman.h>
  29 #include <sys/stat.h>
  30 #include <string.h>
  31 #include <errno.h>
  32
  33 #include <sys/ioctl.h>
  34 #include "mtd-api.h"
  35 #include "mtd.h"
  36 #include "crc32.h"
  37 #include "bcm_tag.h"
  38
  39 ssize_t pread(int fd, void *buf, size_t count, off_t offset);
  40 ssize_t pwrite(int fd, const void *buf, size_t count, off_t offset);
  41
  42 #define CRC_START 0xFFFFFFFF
  43
  44 static uint32_t strntoul(char *str, char **endptr, int base, size_t len) {
  45   char *newstr;
  46   uint32_t res = 0;
  47
  48   newstr = calloc(len + 1, sizeof(char));
  49   if (newstr) {
  50         strncpy(newstr, str, len);
  51         res = strtoul(newstr, endptr, base);
  52         free(newstr);
  53   }
  54   return res;
  55 }
  56
  57 uint32_t compute_crc32(uint32_t crc, off_t start, size_t compute_len, int fd)
  58 {
  59         uint8_t readbuf[1024];
  60         ssize_t res;
  61         off_t offset = start;
  62
  63         /* Read a buffer's worth of bytes  */
  64         while (fd && (compute_len >= sizeof(readbuf))) {
  65                 res = pread(fd, readbuf, sizeof(readbuf), offset);
  66                 crc = crc32(crc, readbuf, res);
  67                 compute_len = compute_len - res;
  68                 offset += res;
  69         }
  70
  71         /* Less than buffer-size bytes remains, read compute_len bytes */
  72         if (fd && (compute_len > 0)) {
  73           res = pread(fd, readbuf, compute_len, offset);
  74           crc = crc32(crc, readbuf, res);
  75         }
  76
  77         return crc;
  78 }
  79
  80 int
  81 trx_check(int imagefd, const char *mtd, char *buf, int *len)
  82 {
  83     struct bcm_tag *tag = (const struct bcm_tag *) buf;
  84         int fd;
  85         uint32_t headerCRC;
  86         uint32_t imageLen;
  87
  88         if (strcmp(mtd, "linux") != 0)
  89                 return 1;
  90
  91         *len = read(imagefd, buf, sizeof(struct bcm_tag));
  92         if (*len < sizeof(struct bcm_tag)) {
  93                 fprintf(stdout, "Could not get image header, file too small (%d bytes)\n", *len);
  94                 return 0;
  95         }
  96         headerCRC = crc32buf(buf, offsetof(struct bcm_tag, headerCRC));
  97         if (*(uint32_t *)(&tag->headerCRC[0]) != headerCRC) {
  98
  99           if (quiet < 2) {
 100                 fprintf(stderr, "Bad header CRC got %08lx, calculated %08lx\n",
 101                                 *(uint32_t *)(&tag->headerCRC[0]), headerCRC);
 102                 fprintf(stderr, "This is not the correct file format; refusing to flash.\n"
 103                                 "Please specify the correct file or use -f to force.\n");
 104           }
 105           return 0;
 106         }
 107
 108         /* check if image fits to mtd device */
 109         fd = mtd_check_open(mtd);
 110         if(fd < 0) {
 111                 fprintf(stderr, "Could not open mtd device: %s\n", mtd);
 112                 exit(1);
 113         }
 114
 115         imageLen = strntoul(&tag->totalLength[0], NULL, 10, IMAGE_LEN);
 116
 117         if(mtdsize < imageLen) {
 118                 fprintf(stderr, "Image too big for partition: %s\n", mtd);
 119                 close(fd);
 120                 return 0;
 121         }
 122
 123         close(fd);
 124         return 1;
 125 }
 126
 127 int
 128 mtd_fixtrx(const char *mtd, size_t offset)
 129 {
 130         int fd;
 131         struct bcm_tag *tag;
 132         char *buf;
 133         ssize_t res;
 134         size_t block_offset;
 135         uint32_t cfelen, imagelen, imagestart, rootfslen;
 136         uint32_t imagecrc, rootfscrc, headercrc;
 137         cfelen = imagelen = imagestart = imagecrc = rootfscrc = headercrc = rootfslen = 0;
 138
 139         if (quiet < 2)
 140                 fprintf(stderr, "Trying to fix trx header in %s at 0x%x...\n", mtd, offset);
 141
 142         block_offset = offset & ~(erasesize - 1);
 143         offset -= block_offset;
 144
 145         fd = mtd_check_open(mtd);
 146         if(fd < 0) {
 147                 fprintf(stderr, "Could not open mtd device: %s\n", mtd);
 148                 exit(1);
 149         }
 150
 151         if (block_offset + erasesize > mtdsize) {
 152                 fprintf(stderr, "Offset too large, device size 0x%x\n", mtdsize);
 153                 exit(1);
 154         }
 155
 156         buf = malloc(erasesize);
 157         if (!buf) {
 158                 perror("malloc");
 159                 exit(1);
 160         }
 161
 162         res = pread(fd, buf, erasesize, block_offset);
 163         if (res != erasesize) {
 164                 perror("pread");
 165                 exit(1);
 166         }
 167
 168         tag = (struct bcm_tag *) (buf + offset);
 169
 170         cfelen = strntoul(&tag->cfeLength[0], NULL, 10, IMAGE_LEN);
 171         if (cfelen) {
 172           fprintf(stderr, "Non-zero CFE length.  This is currently unsupported.\n");
 173           exit(1);
 174         }
 175
 176         if (quiet < 2) {
 177           fprintf(stderr, "Verifying we actually have an imagetag.\n");
 178         }
 179
 180         headercrc = compute_crc32(CRC_START, offset, offsetof(struct bcm_tag, headerCRC), fd);
 181         if (headercrc != *(uint32_t *)(&tag->headerCRC[0])) {
 182                 fprintf(stderr, "Tag verify failed.  This may not be a valid image.\n");
 183                 exit(1);
 184         }
 185
 186         if (quiet < 2) {
 187           fprintf(stderr, "Checking current fixed status.\n");
 188         }
 189
 190         rootfslen = strntoul(&tag->rootLength[0], NULL, 10, IMAGE_LEN);
 191         if (rootfslen == 0) {
 192           if (quiet < 2)
 193                 fprintf(stderr, "Header already fixed, exiting\n");
 194           close(fd);
 195           return 0;
 196         }
 197
 198         if (quiet < 2) {
 199           fprintf(stderr, "Setting root length to 0.\n");
 200         }
 201
 202         sprintf(&tag->rootLength[0], "%lu", 0);
 203         strncpy(&tag->totalLength[0], &tag->kernelLength[0], IMAGE_LEN);
 204
 205         if (quiet < 2) {
 206           fprintf(stderr, "Recalculating CRCs.\n");
 207         }
 208
 209         imagestart = sizeof(tag);
 210         memcpy(&tag->imageCRC[0], &tag->kernelCRC[0], CRC_LEN);
 211         memcpy(&tag->fskernelCRC[0], &tag->kernelCRC[0], CRC_LEN);
 212         rootfscrc = CRC_START;
 213         memcpy(&tag->rootfsCRC[0], &rootfscrc, sizeof(uint32_t));
 214         headercrc = crc32(CRC_START, tag, offsetof(struct bcm_tag, headerCRC));
 215         memcpy(&tag->headerCRC[0], &headercrc, sizeof(uint32_t));
 216
 217         if (quiet < 2) {
 218           fprintf(stderr, "Erasing imagetag block\n");
 219         }
 220
 221         if (mtd_erase_block(fd, block_offset)) {
 222                 fprintf(stderr, "Can't erase block at 0x%x (%s)\n", block_offset, strerror(errno));
 223                 exit(1);
 224         }
 225
 226         if (quiet < 2) {
 227           fprintf(stderr, "New image crc32: 0x%x, rewriting block\n",
 228                           *(uint32_t *)(&tag->imageCRC[0]));
 229           fprintf(stderr, "New header crc32: 0x%x, rewriting block\n", headercrc);
 230         }
 231
 232         if (pwrite(fd, buf, erasesize, block_offset) != erasesize) {
 233                 fprintf(stderr, "Error writing block (%s)\n", strerror(errno));
 234                 exit(1);
 235         }
 236
 237         if (quiet < 2)
 238                 fprintf(stderr, "Done.\n");
 239
 240         close (fd);
 241         sync();
 242         return 0;
 243
 244 }