utils/ypr0tools/fwcrypt.c

/***************************************************************************
 *             __________               __   ___.
 *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
 *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
 *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
 *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
 *                     \/            \/     \/    \/            \/
 *
 * Copyright (C) 2013 Lorenzo Miori
 *
 * 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 software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
 * KIND, either express or implied.
 *
 ****************************************************************************/

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <stdarg.h>
#include <getopt.h>
#include <stdint.h>
#include "common.h"

static char* input_dir = NULL;
static FILE* output_file = NULL;
static struct firmware_data fw;

static void cleanup(void)
{
    for (int i = 0; i < YPR0_COMPONENTS_COUNT; i++)
    {
        free(fw.component_data[i]);
    }
}

static void die(int error)
{
    if (output_file != NULL)
        fclose(output_file);
    free(input_dir);
    cleanup();
    exit(error);
}

static void pad4byte(char byte, FILE* handle) {
    int padding = 4 - ftell(handle) % 4;
    if (padding != 4) {
        while (padding-- > 0) {
            fwrite(&byte, 1, 1, handle);
        }
    }
}

int main(int argc, char **argv)
{
    FILE* component_handle = NULL;
    FILE* rev_info_file = NULL;
    int error = 0;
    char* tmp_path = malloc(MAX_PATH);

    memset(&fw, 0, sizeof(fw));

    if (argc < 2)
    {
        printf(
            "Crypts Samsung YP-R0/YP-R1 ROM file format\n"
            "Usage: fwcrypt <output ROM file path\n"
        );
        return 1;
    }

    input_dir = malloc(MAX_PATH);
    input_dir[0] = '\0';
    if (argc > 2)
    {
        strcpy(input_dir, argv[2]);
    }

    /* open the output file for write */
    output_file = fopen(argv[1], "wb");
    if (output_file == NULL)
    {
        fprintf(stderr, "Cannot open file for writing: %m\n");
        die(SAMSUNG_WRITE_ERROR);
    }

    /* write generic header */
    join_path(tmp_path, input_dir, "RevisionInfo.txt");
    rev_info_file = fopen(tmp_path, "rb");
    if (rev_info_file != NULL)
    {
        for (int i = 0; i < GENERIC_HEADER_LINES; i++)
        {
            char header[MAX_HEADER_LEN];
            error += fgets(header, MAX_HEADER_LEN, rev_info_file) == NULL;
            error += fprintf(output_file, "%s", header) != (signed)strlen(header);
        }
        fclose(rev_info_file);
    }
    else
    {
        /* write some generic information */
        error += fprintf(output_file, YPR0_VERSION) != strlen(YPR0_VERSION);
        error += fprintf(output_file, YPR0_TARGET) != strlen(YPR0_TARGET);
        error += fprintf(output_file, YPR0_USER) != strlen(YPR0_USER);
        error += fprintf(output_file, YPR0_DIR) != strlen(YPR0_DIR);
        error += fprintf(output_file, YPR0_TIME) != strlen(YPR0_TIME);
    }

    if(error != 0)
    {
        fprintf(stderr, "Cannot write generic header\n");
        die(SAMSUNG_WRITE_ERROR);
    }

    for (int i = 0; i < YPR0_COMPONENTS_COUNT; i++)
    {
        join_path(tmp_path, input_dir, firmware_filenames[i]);
        component_handle = fopen(tmp_path, "rb");
        if (component_handle == NULL)
        {
            fprintf(stderr, "Error while reading firmware component.\n");
            die(SAMSUNG_READ_ERROR);
        }
        fw.component_size[i] = get_filesize(component_handle);
        fw.component_data[i] = malloc(fw.component_size[i] * sizeof(char));
        fread(fw.component_data[i], sizeof(char), fw.component_size[i], component_handle);
        fclose(component_handle);

        /* compute checksum */
        md5sum(fw.component_checksum[i], fw.component_data[i], fw.component_size[i]);
        printf("%s : size(%ld),checksum(%s)\n", firmware_components[i],
            fw.component_size[i], fw.component_checksum[i]);
        /* write metadata header to file */
        if (fprintf(output_file, "%s : size(%ld),checksum(%s)\n", firmware_components[i],
            fw.component_size[i], fw.component_checksum[i]) < 0)
        {
            fprintf(stderr, "Error writing to output file.\n");
            die(SAMSUNG_WRITE_ERROR);
        }
    }

    /* Padding */
    pad4byte('\n', output_file);

    /* write final data to the firmware file */
    for (int i = 0; i < YPR0_COMPONENTS_COUNT; i++)
    {
        /* the bootloader needs to be patched: add checksum of the components */
        if (strcmp("MBoot", firmware_components[i]) == 0)
        {
             int index=MBOOT_CHECKSUM_OFFSET;
             for (int z = 0; z < YPR0_COMPONENTS_COUNT; z++)
             {
                index += sprintf(fw.component_data[i] + index, "%ld:%s\n",
                                 fw.component_size[z], fw.component_checksum[z]);
             }
        }
        /* crypt data */
        cyclic_xor(fw.component_data[i], fw.component_size[i], g_yp_key, sizeof(g_yp_key));
        /* write data */
        size_t written = fwrite(fw.component_data[i], sizeof(char),
                                fw.component_size[i], output_file);
        if (written != fw.component_size[i])
        {
            fprintf(stderr, "%s: error writing data to file. Written %ld bytes\n",
                   firmware_components[i], written);
            die(SAMSUNG_WRITE_ERROR);
        }
        /* padding */
        if (i < (YPR0_COMPONENTS_COUNT-1))
            pad4byte('\0', output_file);
    }

    /* free the big amount of memory and close handles */
    die(SAMSUNG_SUCCESS);
}