exynos-usbdl.c

/* exynos-usbdl - github.com/frederic/exynos-usbdl
 * SPDX-License-Identifier: GPL-3.0-or-later
 */

#include <stdlib.h>
#include <stdio.h>
#include <stdint.h>
#include <string.h>
#include <assert.h>
#include "libusb-1.0/libusb.h"

#define DEBUG	1
#define VENDOR_ID	0x18d1
#define PRODUCT_ID	0x4f00
#define BLOCK_SIZE		512
#define CHUNK_SIZE	(uint32_t)0xfffe00

#if DEBUG
#define dprint(args...) printf(args)
#else
#define dprint(args...)
#endif

libusb_device_handle *handle = NULL;

#define MAX_PAYLOAD_SIZE	(BLOCK_SIZE - 10)
typedef struct __attribute__ ((__packed__)) dldata_s {
	u_int32_t unk0;
	u_int32_t size;// header(8) + data(n) + footer(2)
	u_int8_t data[];
	//u_int16_t footer;
} dldata_t;

static int send(dldata_t *payload) {
	int rc;
	int transferred;
	uint total_size = payload->size;
	uint8_t *payload_ptr = (uint8_t *)payload;

	do {
		rc = libusb_bulk_transfer(handle, LIBUSB_ENDPOINT_OUT | 2, payload_ptr, (total_size < BLOCK_SIZE ? total_size : BLOCK_SIZE), &transferred, 0);
		if(rc) {
			fprintf(stderr, "Error libusb_bulk_transfer: %s\n", libusb_error_name(rc));
			return rc;
		}
		dprint("libusb_bulk_transfer: transferred=%d\n", transferred);
		payload_ptr += transferred;
		assert(total_size>=transferred);
		total_size -= transferred;
	} while(total_size > 0);

	return rc;
}

int main(int argc, char *argv[])
{
	libusb_context *ctx;
	FILE *fd;
	dldata_t *payload;
	size_t payload_size, fd_size;
	int target_id = -1;
	uint8_t mode;
	int rc;

	if (!(argc == 2 || argc == 3)) {
		printf("Usage: %s <input_file> [<output_file>]\n", argv[0]);
		printf("\tmode: mode of operation\n");
		printf("\tinput_file: payload binary to load and execute\n");
		return EXIT_SUCCESS;
	}

	fd = fopen(argv[1],"rb");
	if (fd == NULL) {
		fprintf(stderr, "Can't open input file %s !\n", argv[1]);
		return EXIT_FAILURE;
	}

	fseek(fd, 0, SEEK_END);
	fd_size = ftell(fd);

	payload_size = sizeof(dldata_t) + fd_size + 2;// +2 bytes for footer

	payload = (dldata_t*)calloc(1, payload_size);
	payload->size = payload_size;

	fseek(fd, 0, SEEK_SET);
	payload_size = fread(&payload->data, 1, fd_size, fd);
	if (payload_size != fd_size) {
		fprintf(stderr, "Error: cannot read entire file !\n");
		return EXIT_FAILURE;
	}

	rc = libusb_init (&ctx);
	if (rc < 0)
	{
		fprintf(stderr, "Error: failed to initialise libusb: %s\n", libusb_error_name(rc));
		return EXIT_FAILURE;
	}

	#if DEBUG
	libusb_set_option(ctx, LIBUSB_OPTION_LOG_LEVEL, LIBUSB_LOG_LEVEL_DEBUG);
	#endif

	handle = libusb_open_device_with_vid_pid(NULL, VENDOR_ID, PRODUCT_ID);
	if (!handle) {
		fprintf(stderr, "Error: cannot open device %04x:%04x\n", VENDOR_ID, PRODUCT_ID);
		libusb_exit (NULL);
		return EXIT_FAILURE;
	}

	libusb_set_auto_detach_kernel_driver(handle, 1);
	rc = libusb_claim_interface(handle, 0);
	if(rc) {
		fprintf(stderr, "Error claiming interface: %s\n", libusb_error_name(rc));
		return EXIT_FAILURE;
	}
	printf("Sending file %s (0x%lx)...\n", argv[1], fd_size);
	rc = send(payload);
	if(!rc)
		printf("File %s sent !\n", argv[1]);

	#if DEBUG
	sleep(5);
	#endif
	libusb_release_interface(handle, 0);

	if (handle) {
		libusb_close (handle);
	}

	libusb_exit (NULL);

	return EXIT_SUCCESS;
}