wrapcsys.c

Boot code for ADM5120 with serial console for Edimax router.

/*
 *	Tool to wrap a stripped ELF kernel image in a CSYS wrapper
 *	Original code found in EdiLinux/AP/goahead-2.1.1/LINUX/cvimg.c
 *	Original Author:		David Hsu	<[e-mail]>
 *	Modified by:			Dan Everett
 *	Copyright 2006 Dan Everett, All Rights Reserved
 */

#include <stdlib.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <string.h>

/*	Start of things pulled from apmib.h */
#define FW_HEADER			((char *) "CSYS")
#define DEFAULT_START_ADDR	0x80500000
#define SIGNATURE_LEN		4
#define WORD_SWAP(v)		(v)
#define DWORD_SWAP(v)		(v)

typedef struct img_header {
	unsigned char signature[SIGNATURE_LEN] __attribute__ ((packed));
	unsigned long startAddr __attribute__ ((packed));
	unsigned long len __attribute__ ((packed));
} IMG_HEADER_T, *IMG_HEADER_Tp;
/*	End of things pulled from apmib.h */


unsigned short calculateChecksum(char *buf, int len)
{
	int i, j;
	unsigned short tmp, sum = 0;

	j = (len / 2) * 2;

	for (i = 0; i < j; i += 2) {
		tmp = *((unsigned short *) (buf + i));
		sum += WORD_SWAP(tmp);
	}

	if (len % 2) {
		tmp = buf[len - 1];
		sum += WORD_SWAP(tmp);
	}

	return ~sum + 1;
}

int main(int argc, char** argv)
{
//	char inFile[80] = {0}, outFile[80] = {0};
	char *infile = NULL, *outfile = NULL;
	int fh, size;
	struct stat status;
	char *buf;
//	unsigned long startAddr;
	unsigned int startAddr;
	unsigned short checksum;
	IMG_HEADER_Tp pHeader;

	/* Parse input arguments */
	if (argc != 3 && argc != 4) {
		printf("Usage: %s input-file output-file [start-addr]\n", basename(argv[0]));
		printf("       \"start-addr\" is optional.  If not supplied,\n");
		printf("       the default value of %.8X will be used.\n", DEFAULT_START_ADDR);
		return 1;
	}

	infile  = argv[1];
	outfile = argv[2];
//	sscanf(argv[1], "%s", inFile);
//	sscanf(argv[2], "%s", outFile);

	if (argc == 4)
		sscanf(argv[3], "%x", &startAddr);
	else
		startAddr = DEFAULT_START_ADDR;

	printf("\nUsing start address: %.8X\n\n", startAddr);

	/* Check input file and allocate a buffer */
//	if (stat(inFile, &status) < 0) {
	if (stat(infile, &status) < 0) {
		printf("Can't stat file \"%s\"\n", infile);
		return 2;
	}

	size = status.st_size + sizeof(IMG_HEADER_T) + sizeof(checksum);

	if (size % 2)
		size++;		/* Length must be an even number */

	buf = calloc(size, 1);

	if (buf == NULL) {
		printf("Failed to allocate a buffer\n");
		return 3;
	}

//	memset(buf, '\0', size);
	pHeader = (IMG_HEADER_Tp) buf;
	buf += sizeof(IMG_HEADER_T);

	/* Read the file and assemble a header */
//	fh = open(inFile, O_RDONLY);
	fh = open(infile, O_RDONLY);

	if (fh == -1) {
		printf("Error opening input file %s\n", infile);
		free(pHeader);
		return 4;
	}

	lseek(fh, 0L, SEEK_SET);

	if (read(fh, buf, status.st_size) != status.st_size) {
		printf("Error reading input file %s\n", infile);
		close(fh);
		free(pHeader);
		return 5;
	}

	close(fh);

	/* Set the signature (usually CSYS) */
	memcpy(pHeader->signature, FW_HEADER, SIGNATURE_LEN);
	pHeader->len = DWORD_SWAP((size - sizeof(IMG_HEADER_T)));
	pHeader->startAddr = DWORD_SWAP(startAddr);

	/* Calculate and save checksum */
	checksum = WORD_SWAP(calculateChecksum(buf, status.st_size));
	*((unsigned short *) &buf[size - sizeof(IMG_HEADER_T) - sizeof(checksum)]) = checksum;

	/* Write image to output file */
//	fh = open(outFile, O_RDWR|O_CREAT|O_TRUNC);
	fh = open(outfile, O_RDWR|O_CREAT|O_TRUNC);

	if ( fh == -1 ) {
		printf("Error opening output file %s\n", outfile);
		free(pHeader);
		return 6;
	}

	write(fh, pHeader, size);
	close(fh);

	/* Set permission bits for new file */
	chmod(outfile, S_IRUSR | S_IWRITE | S_IRGRP | S_IROTH);

	printf("Image generated successfully.  Length:   %.8X (decimal %d)\n", (unsigned int) DWORD_SWAP(pHeader->len), (int) DWORD_SWAP(pHeader->len));
	printf("                               Checksum: %.4X\n\n", checksum);

	/* Do this last since those last printf stmts need buffer data! */
	free(pHeader);

	return 0;
}