#include <stdlib.h>
#include <stdio.h>
#include <fcntl.h>

#define KERNLDR_START_SECTOR 1
#define HD_SECTOR_SIZE 512

int main(int argc, char* argv[])
{
	if(argc == 3)
	{
		char *input = argv[1];
		char *output = argv[2];
		printf("Copy kernLdr from <%s> to <%s> :\n", input, output);

		int inputFile = open(input, O_RDONLY , 0664);
		if(inputFile == -1)
		{
			fprintf(stderr, "Error when openning file <%s>\n", input);
			return 1;
		}

		int outputFile = open(output, O_WRONLY | O_CREAT, 0664);
		if(outputFile == -1)
		{
			fprintf(stderr, "Error when openning file <%s>\n", output);
			return 1;
		}

		lseek(inputFile, 0, SEEK_SET);
		lseek(outputFile, HD_SECTOR_SIZE * KERNLDR_START_SECTOR, SEEK_SET);

		struct stat info;
		fstat(inputFile, &info);
		unsigned int kernLdrCodeSize = info.st_size;

		if(kernLdrCodeSize >= 32256)
		{
			perror("Error kernLdr is too large\n");
			close(inputFile);
			close(outputFile);
			return 2;
		}

		unsigned char *kernLdrCode = malloc(kernLdrCodeSize);
		int bytesRead = read(inputFile, kernLdrCode, kernLdrCodeSize);
		if(bytesRead == -1)
		{
			perror("Reading error\n");
			free(kernLdrCode);
			close(inputFile);
			close(outputFile);
			return 3;
		}

		int bytesWrite = write(outputFile, kernLdrCode, kernLdrCodeSize);
		if(bytesWrite == -1)
		{
			perror("Writing error\n");
			free(kernLdrCode);
			close(inputFile);
			close(outputFile);
			return 3;
		}

		free(kernLdrCode);
		close(inputFile);
		close(outputFile);
		printf("done\n");
	}
	else
	{
		perror("[help] : w_kernLdr <kernLdr> <disk image>\n");
		return 4;
	}
	return 0;
}