main.c

/*
 * dfu-util
 *
 * Copyright 2007-2008 by OpenMoko, Inc.
 * Copyright 2010-2012 Stefan Schmidt
 * Copyright 2013-2014 Hans Petter Selasky <hps@bitfrost.no>
 * Copyright 2010-2021 Tormod Volden
 *
 * Originally written by Harald Welte <laforge@openmoko.org>
 *
 * Based on existing code of dfu-programmer-0.4
 *
 * 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
 */

#ifdef HAVE_CONFIG_H
# include "config.h"
#endif

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <getopt.h>
#include <libusb.h>
#include <errno.h>
#include <fcntl.h>
#include <limits.h>

#include "portable.h"
#include "dfu.h"
#include "dfu_file.h"
#include "dfu_load.h"
#include "dfu_util.h"
#include "dfuse.h"

int verbose = 0;

struct dfu_if *dfu_root = NULL;

char *match_path = NULL;
int match_vendor = -1;
int match_product = -1;
int match_vendor_dfu = -1;
int match_product_dfu = -1;
int match_config_index = -1;
int match_iface_index = -1;
int match_iface_alt_index = -1;
int match_devnum = -1;
const char *match_iface_alt_name = NULL;
const char *match_serial = NULL;
const char *match_serial_dfu = NULL;

static int parse_match_value(const char *str, int default_value)
{
	char *remainder;
	int value;

	if (str == NULL) {
		value = default_value;
	} else if (*str == '*') {
		value = -1; /* Match anything */
	} else if (*str == '-') {
		value = 0x10000; /* Impossible vendor/product ID */
	} else {
		value = strtoul(str, &remainder, 16);
		if (remainder == str) {
			value = default_value;
		}
	}
	return value;
}

static void parse_vendprod(const char *str)
{
	const char *comma;
	const char *colon;

	/* Default to match any DFU device in runtime or DFU mode */
	match_vendor = -1;
	match_product = -1;
	match_vendor_dfu = -1;
	match_product_dfu = -1;

	comma = strchr(str, ',');
	if (comma == str) {
		/* DFU mode vendor/product being specified without any runtime
		 * vendor/product specification, so don't match any runtime device */
		match_vendor = match_product = 0x10000;
	} else {
		colon = strchr(str, ':');
		if (colon != NULL) {
			++colon;
			if ((comma != NULL) && (colon > comma)) {
				colon = NULL;
			}
		}
		match_vendor = parse_match_value(str, match_vendor);
		match_product = parse_match_value(colon, match_product);
		if (comma != NULL) {
			/* Both runtime and DFU mode vendor/product specifications are
			 * available, so default DFU mode match components to the given
			 * runtime match components */
			match_vendor_dfu = match_vendor;
			match_product_dfu = match_product;
		}
	}
	if (comma != NULL) {
		++comma;
		colon = strchr(comma, ':');
		if (colon != NULL) {
			++colon;
		}
		match_vendor_dfu = parse_match_value(comma, match_vendor_dfu);
		match_product_dfu = parse_match_value(colon, match_product_dfu);
	}
}

static void parse_serial(char *str)
{
	char *comma;

	match_serial = str;
	comma = strchr(str, ',');
	if (comma == NULL) {
		match_serial_dfu = match_serial;
	} else {
		*comma++ = 0;
		match_serial_dfu = comma;
	}
	if (*match_serial == 0) match_serial = NULL;
	if (*match_serial_dfu == 0) match_serial_dfu = NULL;
}

static int parse_number(char *str, char *nmb)
{
	char *endptr;
	long val;

	errno = 0;
	val = strtol(nmb, &endptr, 0);

	if ((errno == ERANGE && (val == LONG_MAX || val == LONG_MIN))
		|| (errno != 0 && val == 0) || (*endptr != '\0')) {
		errx(EX_USAGE, "Something went wrong with the argument of --%s\n", str);
	}

	if (endptr == nmb) {
		errx(EX_USAGE, "No digits were found from the argument of --%s\n", str);
	}

	return (int)val;
}

static void help(void)
{
	fprintf(stderr, "Usage: dfu-util [options] ...\n"
		"  -h --help\t\t\tPrint this help message\n"
		"  -V --version\t\t\tPrint the version number\n"
		"  -v --verbose\t\t\tPrint verbose debug statements\n"
		"  -l --list\t\t\tList currently attached DFU capable devices\n");
	fprintf(stderr, "  -e --detach\t\t\tDetach currently attached DFU capable devices\n"
		"  -E --detach-delay seconds\tTime to wait before reopening a device after detach\n"
		"  -d --device <vendor>:<product>[,<vendor_dfu>:<product_dfu>]\n"
		"\t\t\t\tSpecify Vendor/Product ID(s) of DFU device\n"
		"  -n --devnum <dnum>\t\tMatch given device number (devnum from --list)\n"
		"  -p --path <bus-port. ... .port>\tSpecify path to DFU device\n"
		"  -c --cfg <config_nr>\t\tSpecify the Configuration of DFU device\n"
		"  -i --intf <intf_nr>\t\tSpecify the DFU Interface number\n"
		"  -S --serial <serial_string>[,<serial_string_dfu>]\n"
		"\t\t\t\tSpecify Serial String of DFU device\n"
		"  -a --alt <alt>\t\tSpecify the Altsetting of the DFU Interface\n"
		"\t\t\t\tby name or by number\n");
	fprintf(stderr, "  -t --transfer-size <size>\tSpecify the number of bytes per USB Transfer\n"
		"  -U --upload <file>\t\tRead firmware from device into <file>\n"
		"  -Z --upload-size <bytes>\tSpecify the expected upload size in bytes\n"
		"  -D --download <file>\t\tWrite firmware from <file> into device\n"
		"  -R --reset\t\t\tIssue USB Reset signalling once we're finished\n"
		"  -w --wait\t\t\tWait for device to appear\n"
		"  -s --dfuse-address address<:...>\tST DfuSe mode string, specifying target\n"
		"\t\t\t\taddress for raw file download or upload (not\n"
		"\t\t\t\tapplicable for DfuSe file (.dfu) downloads).\n"
		"\t\t\t\tAdd more DfuSe options separated with ':'\n"
		"\t\tleave\t\tLeave DFU mode (jump to application)\n"
		"\t\tmass-erase\tErase the whole device (requires \"force\")\n"
		"\t\tunprotect\tErase read protected device (requires \"force\")\n"
		"\t\twill-reset\tExpect device to reset (e.g. option bytes write)\n"
		"\t\tforce\t\tYou really know what you are doing!\n"
		"\t\t<length>\tLength of firmware to upload from device\n"
		);
}

static void print_version(void)
{
	printf(PACKAGE_STRING "\n\n");
	printf("Copyright 2005-2009 Weston Schmidt, Harald Welte and OpenMoko Inc.\n"
	       "Copyright 2010-2021 Tormod Volden and Stefan Schmidt\n"
	       "This program is Free Software and has ABSOLUTELY NO WARRANTY\n"
	       "Please report bugs to " PACKAGE_BUGREPORT "\n\n");
}

static struct option opts[] = {
	{ "help", 0, 0, 'h' },
	{ "version", 0, 0, 'V' },
	{ "verbose", 0, 0, 'v' },
	{ "list", 0, 0, 'l' },
	{ "detach", 0, 0, 'e' },
	{ "detach-delay", 1, 0, 'E' },
	{ "device", 1, 0, 'd' },
	{ "path", 1, 0, 'p' },
	{ "configuration", 1, 0, 'c' },
	{ "cfg", 1, 0, 'c' },
	{ "interface", 1, 0, 'i' },
	{ "intf", 1, 0, 'i' },
	{ "altsetting", 1, 0, 'a' },
	{ "alt", 1, 0, 'a' },
	{ "serial", 1, 0, 'S' },
	{ "transfer-size", 1, 0, 't' },
	{ "upload", 1, 0, 'U' },
	{ "upload-size", 1, 0, 'Z' },
	{ "download", 1, 0, 'D' },
	{ "reset", 0, 0, 'R' },
	{ "dfuse-address", 1, 0, 's' },
	{ "devnum",1, 0, 'n' },
	{ "wait", 1, 0, 'w' },
	{ 0, 0, 0, 0 }
};

int main(int argc, char **argv)
{
	int expected_size = 0;
	unsigned int transfer_size = 0;
	enum mode mode = MODE_NONE;
	struct dfu_status status;
	libusb_context *ctx;
	struct dfu_file file;
	char *end;
	int final_reset = 0;
	int wait_device = 0;
	int ret;
	int dfuse_device = 0;
	int fd;
	const char *dfuse_options = NULL;
	int detach_delay = 5;
	uint16_t runtime_vendor;
	uint16_t runtime_product;

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

	/* make sure all prints are flushed */
	setvbuf(stdout, NULL, _IONBF, 0);

	while (1) {
		int c, option_index = 0;
		c = getopt_long(argc, argv, "hVvleE:d:p:c:i:a:S:t:U:D:Rs:Z:wn:", opts,
				&option_index);
		if (c == -1)
			break;

		switch (c) {
		case 'h':
			help();
			exit(EX_OK);
			break;
		case 'V':
			mode = MODE_VERSION;
			break;
		case 'v':
			verbose++;
			break;
		case 'l':
			mode = MODE_LIST;
			break;
		case 'e':
			mode = MODE_DETACH;
			break;
		case 'E':
			detach_delay = parse_number("detach-delay", optarg);
			break;
		case 'd':
			parse_vendprod(optarg);
			break;
		case 'p':
#if (defined(LIBUSB_API_VERSION) && LIBUSB_API_VERSION >= 0x01000102) || (defined(LIBUSBX_API_VERSION) && LIBUSBX_API_VERSION >= 0x01000102)
			match_path = optarg;
#else
			errx(EX_SOFTWARE, "This dfu-util was built without USB path support");
#endif
			break;
		case 'c':
			/* Configuration */
			match_config_index = parse_number("cfg", optarg);
			break;
		case 'i':
			/* Interface */
			match_iface_index = parse_number("intf", optarg);
			break;
		case 'a':
			/* Interface Alternate Setting */
			match_iface_alt_index = strtoul(optarg, &end, 0);
			if (*end) {
				match_iface_alt_name = optarg;
				match_iface_alt_index = -1;
			}
			break;
		case 'n':
			match_devnum = atoi(optarg);
			break;
		case 'S':
			parse_serial(optarg);
			break;
		case 't':
			transfer_size = parse_number("transfer-size", optarg);
			break;
		case 'U':
			mode = MODE_UPLOAD;
			file.name = optarg;
			break;
		case 'Z':
			expected_size = parse_number("upload-size", optarg);
			break;
		case 'D':
			mode = MODE_DOWNLOAD;
			file.name = optarg;
			break;
		case 'R':
			final_reset = 1;
			break;
		case 's':
			dfuse_options = optarg;
			break;
		case 'w':
			wait_device = 1;
			break;
		default:
			help();
			exit(EX_USAGE);
			break;
		}
	}
	if (optind != argc) {
		fprintf(stderr, "Error: Unexpected argument: %s\n\n", argv[optind]);
		help();
		exit(EX_USAGE);
	}

	print_version();
	if (mode == MODE_VERSION) {
		exit(EX_OK);
	}

#if defined(LIBUSB_API_VERSION) || defined(LIBUSBX_API_VERSION)
	if (verbose) {
		const struct libusb_version *ver;
		ver = libusb_get_version();
		printf("libusb version %i.%i.%i%s (%i)\n", ver->major,
		       ver->minor, ver->micro, ver->rc, ver->nano);
	}
#else
	warnx("libusb version is ancient");
#endif

	if (mode == MODE_NONE && !dfuse_options) {
		fprintf(stderr, "You need to specify one of -D or -U\n");
		help();
		exit(EX_USAGE);
	}

	if (match_config_index == 0) {
		/* Handle "-c 0" (unconfigured device) as don't care */
		match_config_index = -1;
	}

	if (mode == MODE_DOWNLOAD) {
		dfu_load_file(&file, MAYBE_SUFFIX, MAYBE_PREFIX);
		/* If the user didn't specify product and/or vendor IDs to match,
		 * use any IDs from the file suffix for device matching */
		if (match_vendor < 0 && file.idVendor != 0xffff) {
			match_vendor = file.idVendor;
			printf("Match vendor ID from file: %04x\n", match_vendor);
		}
		if (match_product < 0 && file.idProduct != 0xffff) {
			match_product = file.idProduct;
			printf("Match product ID from file: %04x\n", match_product);
		}
	} else if (mode == MODE_NONE && dfuse_options) {
		/* for DfuSe special commands, match any device */
		mode = MODE_DOWNLOAD;
		file.idVendor = 0xffff;
		file.idProduct = 0xffff;
	}

	if (wait_device) {
		printf("Waiting for device, exit with ctrl-C\n");
	}

	ret = libusb_init_context(&ctx, NULL, 0);
	if (ret)
		errx(EX_IOERR, "unable to initialize libusb: %s", libusb_error_name(ret));

	if (verbose > 2) {
#if defined(LIBUSB_API_VERSION) && LIBUSB_API_VERSION >= 0x01000106
		libusb_set_option(ctx, LIBUSB_OPTION_LOG_LEVEL, LIBUSB_LOG_LEVEL_DEBUG);
#else
		libusb_set_debug(ctx, 255);
#endif
	}
probe:
	probe_devices(ctx);

	if (mode == MODE_LIST) {
		list_dfu_interfaces();
		disconnect_devices();
		libusb_exit(ctx);
		return EX_OK;
	}

	if (dfu_root == NULL) {
		if (wait_device) {
			milli_sleep(20);
			goto probe;
		} else {
			warnx("No DFU capable USB device available");
			libusb_exit(ctx);
			return EX_IOERR;
		}
	} else if (file.bcdDFU == 0x11a && dfuse_multiple_alt(dfu_root)) {
		printf("Multiple alternate interfaces for DfuSe file\n");
	} else if (dfu_root->next != NULL) {
		/* We cannot safely support more than one DFU capable device
		 * with same vendor/product ID, since during DFU we need to do
		 * a USB bus reset, after which the target device will get a
		 * new address */
		errx(EX_IOERR, "More than one DFU capable USB device found! "
		       "Try `--list' and specify the serial number "
		       "or disconnect all but one device\n");
	}

	/* We have exactly one device. Its libusb_device is now in dfu_root->dev */

	printf("Opening DFU capable USB device...\n");
	ret = libusb_open(dfu_root->dev, &dfu_root->dev_handle);
	if (ret || !dfu_root->dev_handle)
		errx(EX_IOERR, "Cannot open device: %s", libusb_error_name(ret));

	printf("Device ID %04x:%04x\n", dfu_root->vendor, dfu_root->product);

	/* If first interface is DFU it is likely not proper run-time */
	if (dfu_root->interface > 0)
		printf("Run-Time device");
	else
		printf("Device");
	printf(" DFU version %04x\n",
	       libusb_le16_to_cpu(dfu_root->func_dfu.bcdDFUVersion));

	if (verbose) {
		printf("DFU attributes: (0x%02x)", dfu_root->func_dfu.bmAttributes);
		if (dfu_root->func_dfu.bmAttributes & USB_DFU_CAN_DOWNLOAD)
			printf(" bitCanDnload");
		if (dfu_root->func_dfu.bmAttributes & USB_DFU_CAN_UPLOAD)
			printf(" bitCanUpload");
		if (dfu_root->func_dfu.bmAttributes & USB_DFU_MANIFEST_TOL)
			printf(" bitManifestationTolerant");
		if (dfu_root->func_dfu.bmAttributes & USB_DFU_WILL_DETACH)
			printf(" bitWillDetach");
		printf("\n");
		printf("Detach timeout %d ms\n", libusb_le16_to_cpu(dfu_root->func_dfu.wDetachTimeOut));
	}

	/* Transition from run-Time mode to DFU mode */
	if (!(dfu_root->flags & DFU_IFF_DFU)) {
		int err;
		/* In the 'first round' during runtime mode, there can only be one
		* DFU Interface descriptor according to the DFU Spec. */

		/* FIXME: check if the selected device really has only one */

		runtime_vendor = dfu_root->vendor;
		runtime_product = dfu_root->product;

		printf("Claiming USB DFU (Run-Time) Interface...\n");
		ret = libusb_claim_interface(dfu_root->dev_handle, dfu_root->interface);
		if (ret < 0) {
			errx(EX_IOERR, "Cannot claim interface %d: %s",
				dfu_root->interface, libusb_error_name(ret));
		}

		/* Needed for some devices where the DFU interface is not the first,
		 * and should also be safe if there are multiple alt settings.
		 * Otherwise skip the request since it might not be supported
		 * by the device and the USB stack may or may not recover */
		if (dfu_root->interface > 0 || dfu_root->flags & DFU_IFF_ALT) {
			printf("Setting Alternate Interface zero...\n");
			ret = libusb_set_interface_alt_setting(dfu_root->dev_handle, dfu_root->interface, 0);
			if (ret < 0) {
				errx(EX_IOERR, "Cannot set alternate interface zero: %s", libusb_error_name(ret));
			}
		}

		printf("Determining device status...\n");
		err = dfu_get_status(dfu_root, &status);
		if (err == LIBUSB_ERROR_PIPE) {
			printf("Device does not implement get_status, assuming appIDLE\n");
			status.bStatus = DFU_STATUS_OK;
			status.bwPollTimeout = 0;
			status.bState  = DFU_STATE_appIDLE;
			status.iString = 0;
		} else if (err < 0) {
			errx(EX_IOERR, "error get_status: %s", libusb_error_name(err));
		} else {
			printf("DFU state(%u) = %s, status(%u) = %s\n", status.bState,
			       dfu_state_to_string(status.bState), status.bStatus,
			       dfu_status_to_string(status.bStatus));
		}
		milli_sleep(status.bwPollTimeout);

		switch (status.bState) {
		case DFU_STATE_appIDLE:
		case DFU_STATE_appDETACH:
			printf("Device really in Run-Time Mode, send DFU "
			       "detach request...\n");
			if (dfu_detach(dfu_root->dev_handle,
				       dfu_root->interface, 1000) < 0) {
				warnx("error detaching");
			}
			if (dfu_root->func_dfu.bmAttributes & USB_DFU_WILL_DETACH) {
				printf("Device will detach and reattach...\n");
			} else {
				printf("Resetting USB...\n");
				ret = libusb_reset_device(dfu_root->dev_handle);
				if (ret < 0 && ret != LIBUSB_ERROR_NOT_FOUND)
					errx(EX_IOERR, "error resetting "
						"after detach: %s", libusb_error_name(ret));
			}
			break;
		case DFU_STATE_dfuERROR:
			printf("dfuERROR, clearing status\n");
			if (dfu_clear_status(dfu_root->dev_handle,
					     dfu_root->interface) < 0) {
				errx(EX_IOERR, "error clear_status");
			}
			/* fall through */
		default:
			warnx("WARNING: Device already in DFU mode? (bState=%d %s)",
			      status.bState, dfu_state_to_string(status.bState));
			libusb_release_interface(dfu_root->dev_handle,
			    dfu_root->interface);
			goto dfustate;
		}
		libusb_release_interface(dfu_root->dev_handle,
					 dfu_root->interface);
		libusb_close(dfu_root->dev_handle);
		dfu_root->dev_handle = NULL;

		/* keeping handles open might prevent re-enumeration */
		disconnect_devices();

		if (mode == MODE_DETACH) {
			libusb_exit(ctx);
			return EX_OK;
		}

		milli_sleep(detach_delay * 1000);

		/* Change match vendor and product to impossible values to force
		 * only DFU mode matches in the following probe */
		match_vendor = match_product = 0x10000;

		probe_devices(ctx);

		if (dfu_root == NULL) {
			errx(EX_IOERR, "Lost device after RESET?");
		} else if (dfu_root->next != NULL) {
			errx(EX_IOERR, "More than one DFU capable USB device found! "
				"Try `--list' and specify the serial number "
				"or disconnect all but one device");
		}

		/* Check for DFU mode device */
		if (!(dfu_root->flags | DFU_IFF_DFU))
			errx(EX_PROTOCOL, "Device is not in DFU mode");

		printf("Opening DFU USB Device...\n");
		ret = libusb_open(dfu_root->dev, &dfu_root->dev_handle);
		if (ret || !dfu_root->dev_handle) {
			errx(EX_IOERR, "Cannot open device");
		}
	} else {
		/* we're already in DFU mode, so we can skip the detach/reset
		 * procedure */
		/* If a match vendor/product was specified, use that as the runtime
		 * vendor/product, otherwise use the DFU mode vendor/product */
		runtime_vendor = match_vendor < 0 ? dfu_root->vendor : match_vendor;
		runtime_product = match_product < 0 ? dfu_root->product : match_product;
	}

dfustate:
#if 0
	printf("Setting Configuration %u...\n", dfu_root->configuration);
	ret = libusb_set_configuration(dfu_root->dev_handle, dfu_root->configuration);
	if (ret < 0) {
		errx(EX_IOERR, "Cannot set configuration: %s", libusb_error_name(ret));
	}
#endif
	printf("Claiming USB DFU Interface...\n");
	ret = libusb_claim_interface(dfu_root->dev_handle, dfu_root->interface);
	if (ret < 0) {
		errx(EX_IOERR, "Cannot claim interface - %s", libusb_error_name(ret));
	}

	if (dfu_root->flags & DFU_IFF_ALT) {
		printf("Setting Alternate Interface #%d ...\n", dfu_root->altsetting);
		ret = libusb_set_interface_alt_setting(dfu_root->dev_handle, dfu_root->interface, dfu_root->altsetting);
		if (ret < 0) {
			errx(EX_IOERR, "Cannot set alternate interface: %s", libusb_error_name(ret));
		}
	}

status_again:
	printf("Determining device status...\n");
	ret = dfu_get_status(dfu_root, &status );
	if (ret < 0) {
		errx(EX_IOERR, "error get_status: %s", libusb_error_name(ret));
	}
	printf("DFU state(%u) = %s, status(%u) = %s\n", status.bState,
	       dfu_state_to_string(status.bState), status.bStatus,
	       dfu_status_to_string(status.bStatus));

	milli_sleep(status.bwPollTimeout);

	switch (status.bState) {
	case DFU_STATE_appIDLE:
	case DFU_STATE_appDETACH:
		errx(EX_PROTOCOL, "Device still in Run-Time Mode!");
		break;
	case DFU_STATE_dfuERROR:
		printf("Clearing status\n");
		if (dfu_clear_status(dfu_root->dev_handle, dfu_root->interface) < 0) {
			errx(EX_IOERR, "error clear_status");
		}
		goto status_again;
		break;
	case DFU_STATE_dfuDNLOAD_IDLE:
	case DFU_STATE_dfuUPLOAD_IDLE:
		printf("Aborting previous incomplete transfer\n");
		if (dfu_abort(dfu_root->dev_handle, dfu_root->interface) < 0) {
			errx(EX_IOERR, "can't send DFU_ABORT");
		}
		goto status_again;
		break;
	case DFU_STATE_dfuIDLE:
	default:
		break;
	}

	if (DFU_STATUS_OK != status.bStatus ) {
		printf("WARNING: DFU Status: '%s'\n",
			dfu_status_to_string(status.bStatus));
		/* Clear our status & try again. */
		if (dfu_clear_status(dfu_root->dev_handle, dfu_root->interface) < 0)
			errx(EX_IOERR, "USB communication error");
		if (dfu_get_status(dfu_root, &status) < 0)
			errx(EX_IOERR, "USB communication error");
		if (DFU_STATUS_OK != status.bStatus)
			errx(EX_PROTOCOL, "Status is not OK: %d", status.bStatus);

		milli_sleep(status.bwPollTimeout);
	}

	printf("DFU mode device DFU version %04x\n",
	       libusb_le16_to_cpu(dfu_root->func_dfu.bcdDFUVersion));

	if (dfu_root->func_dfu.bcdDFUVersion == libusb_cpu_to_le16(0x11a))
		dfuse_device = 1;
	else if (dfuse_options)
		printf("Warning: DfuSe option used on non-DfuSe device\n");

	/* Get from device or user, warn if overridden */
	int func_dfu_transfer_size = libusb_le16_to_cpu(dfu_root->func_dfu.wTransferSize);
	if (func_dfu_transfer_size) {
		printf("Device returned transfer size %i\n", func_dfu_transfer_size);
		if (!transfer_size)
			transfer_size = func_dfu_transfer_size;
		else
			printf("Warning: Overriding device-reported transfer size\n");
	} else {
		if (!transfer_size)
			errx(EX_USAGE, "Transfer size must be specified");
	}

#ifdef __linux__
	/* limited to 4k in libusb Linux backend */
	if ((int)transfer_size > 4096) {
		transfer_size = 4096;
		printf("Limited transfer size to %i\n", transfer_size);
	}
#endif /* __linux__ */

	if (transfer_size < dfu_root->bMaxPacketSize0) {
		transfer_size = dfu_root->bMaxPacketSize0;
		printf("Adjusted transfer size to %i\n", transfer_size);
	}

	switch (mode) {
	case MODE_UPLOAD:
		/* open for "exclusive" writing */
		fd = open(file.name, O_WRONLY | O_BINARY | O_CREAT | O_EXCL | O_TRUNC, 0666);
		if (fd < 0) {
			warn("Cannot open file %s for writing", file.name);
			ret = EX_CANTCREAT;
			break;
		}

		if (dfuse_device || dfuse_options) {
		    ret = dfuse_do_upload(dfu_root, transfer_size, fd, dfuse_options);
		} else {
		    ret = dfuload_do_upload(dfu_root, transfer_size, expected_size, fd);
		}
		close(fd);
		if (ret < 0)
			ret = EX_IOERR;
		else
			ret = EX_OK;
		break;

	case MODE_DOWNLOAD:
		if (((file.idVendor  != 0xffff && file.idVendor  != runtime_vendor) ||
		     (file.idProduct != 0xffff && file.idProduct != runtime_product)) &&
		    ((file.idVendor  != 0xffff && file.idVendor  != dfu_root->vendor) ||
		     (file.idProduct != 0xffff && file.idProduct != dfu_root->product))) {
			errx(EX_USAGE, "Error: File ID %04x:%04x does "
				"not match device (%04x:%04x or %04x:%04x)",
				file.idVendor, file.idProduct,
				runtime_vendor, runtime_product,
				dfu_root->vendor, dfu_root->product);
		}
		if (dfuse_device || dfuse_options || file.bcdDFU == 0x11a) {
			ret = dfuse_do_dnload(dfu_root, transfer_size, &file, dfuse_options);
		} else {
			ret = dfuload_do_dnload(dfu_root, transfer_size, &file);
	 	}
		if (ret < 0)
			ret = EX_IOERR;
		else
			ret = EX_OK;
		break;
	case MODE_DETACH:
		ret = dfu_detach(dfu_root->dev_handle, dfu_root->interface, 1000);
		if (ret < 0) {
			warnx("can't detach");
			/* allow combination with final_reset */
			ret = 0;
		}
		break;
	default:
		warnx("Unsupported mode: %u", mode);
		ret = EX_SOFTWARE;
		break;
	}

	if (!ret && final_reset) {
		ret = dfu_detach(dfu_root->dev_handle, dfu_root->interface, 1000);
		if (ret < 0) {
			/* Even if detach failed, just carry on to leave the
                           device in a known state */
			warnx("can't detach");
		}
		printf("Resetting USB to switch back to Run-Time mode\n");
		ret = libusb_reset_device(dfu_root->dev_handle);
		if (ret < 0 && ret != LIBUSB_ERROR_NOT_FOUND) {
			warnx("error resetting after download: %s", libusb_error_name(ret));
			ret = EX_IOERR;
		}
	}

	libusb_close(dfu_root->dev_handle);
	dfu_root->dev_handle = NULL;

	disconnect_devices();
	libusb_exit(ctx);
	return ret;
}