treewide: fix replace nbd@openwrt.org with nbd@nbd.name
[openwrt.org/openwrt.git] / package / system / mtd / src / seama.c
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/*
 * seama.c
 *
 * Copyright (C) 2011-2012 Gabor Juhos <juhosg@openwrt.org>
 *
 * Based on the trx fixup code:
 *   Copyright (C) 2005 Mike Baker
 *   Copyright (C) 2008 Felix Fietkau <nbd@nbd.name>
 *
 * 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.
 */
 
#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 <errno.h>
#include <arpa/inet.h>
 
#include <sys/ioctl.h>
#include <mtd/mtd-user.h>
#include "mtd.h"
#include "seama.h"
#include "md5.h"
 
#if __BYTE_ORDER == __BIG_ENDIAN
#define STORE32_LE(X)           ((((X) & 0x000000FF) << 24) | (((X) & 0x0000FF00) << 8) | (((X) & 0x00FF0000) >> 8) | (((X) & 0xFF000000) >> 24))
#elif __BYTE_ORDER == __LITTLE_ENDIAN
#define STORE32_LE(X)           (X)
#else
#error unknown endianness!
#endif
 
ssize_t pread(int fd, void *buf, size_t count, off_t offset);
ssize_t pwrite(int fd, const void *buf, size_t count, off_t offset);
 
int
seama_fix_md5(struct seama_entity_header *shdr, int fd, size_t data_offset, size_t data_size)
{
        char *buf;
        ssize_t res;
        MD5_CTX ctx;
        unsigned char digest[16];
        int i;
        int err = 0;
 
        buf = malloc(data_size);
        if (!buf) {
                err = -ENOMEM;
                goto err_out;
        }
 
        res = pread(fd, buf, data_size, data_offset);
        if (res != data_size) {
                perror("pread");
                err = -EIO;
                goto err_free;
        }
 
        MD5_Init(&ctx);
        MD5_Update(&ctx, buf, data_size);
        MD5_Final(digest, &ctx);
 
        if (!memcmp(digest, shdr->md5, sizeof(digest))) {
                if (quiet < 2)
                        fprintf(stderr, "the header is fixed already\n");
                return -1;
        }
 
        if (quiet < 2) {
                fprintf(stderr, "new size:%u, new MD5: ", data_size);
                for (i = 0; i < sizeof(digest); i++)
                        fprintf(stderr, "%02x", digest[i]);
 
                fprintf(stderr, "\n");
        }
 
        /* update the size in the image */
        shdr->size = htonl(data_size);
 
        /* update the checksum in the image */
        memcpy(shdr->md5, digest, sizeof(digest));
 
err_free:
        free(buf);
err_out:
        return err;
}
 
int
mtd_fixseama(const char *mtd, size_t offset)
{
        int fd;
        char *first_block;
        ssize_t res;
        size_t block_offset;
        size_t data_offset;
        size_t data_size;
        struct seama_entity_header *shdr;
 
        if (quiet < 2)
                fprintf(stderr, "Trying to fix SEAMA header in %s at 0x%x...\n",
                        mtd, offset);
 
        block_offset = offset & ~(erasesize - 1);
        offset -= block_offset;
 
        fd = mtd_check_open(mtd);
        if(fd < 0) {
                fprintf(stderr, "Could not open mtd device: %s\n", mtd);
                exit(1);
        }
 
        if (block_offset + erasesize > mtdsize) {
                fprintf(stderr, "Offset too large, device size 0x%x\n",
                        mtdsize);
                exit(1);
        }
 
        first_block = malloc(erasesize);
        if (!first_block) {
                perror("malloc");
                exit(1);
        }
 
        res = pread(fd, first_block, erasesize, block_offset);
        if (res != erasesize) {
                perror("pread");
                exit(1);
        }
 
        shdr = (struct seama_entity_header *)(first_block + offset);
        if (shdr->magic != htonl(SEAMA_MAGIC)) {
                fprintf(stderr, "No SEAMA header found\n");
                exit(1);
        } else if (!ntohl(shdr->size)) {
                fprintf(stderr, "Seama entity with empty image\n");
                exit(1);
        }
 
        data_offset = offset + sizeof(struct seama_entity_header) + ntohs(shdr->metasize);
        data_size = mtdsize - data_offset;
        if (data_size > ntohl(shdr->size))
                data_size = ntohl(shdr->size);
        if (seama_fix_md5(shdr, fd, data_offset, data_size))
                goto out;
 
        if (mtd_erase_block(fd, block_offset)) {
                fprintf(stderr, "Can't erease block at 0x%x (%s)\n",
                        block_offset, strerror(errno));
                exit(1);
        }
 
        if (quiet < 2)
                fprintf(stderr, "Rewriting block at 0x%x\n", block_offset);
 
        if (pwrite(fd, first_block, erasesize, block_offset) != erasesize) {
                fprintf(stderr, "Error writing block (%s)\n", strerror(errno));
                exit(1);
        }
 
        if (quiet < 2)
                fprintf(stderr, "Done.\n");
 
out:
        close (fd);
        sync();
 
        return 0;
}
 
 
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