/*
 * Copyright (C) 2011 matt mooney <mfm@muteddisk.com>
 *               2005-2007 Takahiro Hirofuchi
 *
 * 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, see <http://www.gnu.org/licenses/>.
 */

#include <sysfs/libsysfs.h>

#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <getopt.h>

#include "usbip_common.h"
#include "utils.h"
#include "usbip.h"

enum unbind_status {
	UNBIND_ST_OK,
	UNBIND_ST_USBIP_HOST,
	UNBIND_ST_FAILED
};

static const char usbip_bind_usage_string[] =
	"usbip bind <args>\n"
	"    -b, --busid=<busid>    Bind " USBIP_HOST_DRV_NAME ".ko to device "
	"on <busid>\n";

void usbip_bind_usage(void)
{
	printf("usage: %s", usbip_bind_usage_string);
}

/* call at unbound state */
static int bind_usbip(char *busid)
{
	char bus_type[] = "usb";
	char attr_name[] = "bind";
	char sysfs_mntpath[SYSFS_PATH_MAX];
	char bind_attr_path[SYSFS_PATH_MAX];
	char intf_busid[SYSFS_BUS_ID_SIZE];
	struct sysfs_device *busid_dev;
	struct sysfs_attribute *bind_attr;
	struct sysfs_attribute *bConfValue;
	struct sysfs_attribute *bNumIntfs;
	int i, failed = 0;
	int rc, ret = -1;

	rc = sysfs_get_mnt_path(sysfs_mntpath, SYSFS_PATH_MAX);
	if (rc < 0) {
		err("sysfs must be mounted: %s", strerror(errno));
		return -1;
	}

	snprintf(bind_attr_path, sizeof(bind_attr_path), "%s/%s/%s/%s/%s/%s",
		 sysfs_mntpath, SYSFS_BUS_NAME, bus_type, SYSFS_DRIVERS_NAME,
		 USBIP_HOST_DRV_NAME, attr_name);

	bind_attr = sysfs_open_attribute(bind_attr_path);
	if (!bind_attr) {
		dbg("problem getting bind attribute: %s", strerror(errno));
		return -1;
	}

	busid_dev = sysfs_open_device(bus_type, busid);
	if (!busid_dev) {
		dbg("sysfs_open_device %s failed: %s", busid, strerror(errno));
		goto err_close_bind_attr;
	}

	bConfValue = sysfs_get_device_attr(busid_dev, "bConfigurationValue");
	bNumIntfs  = sysfs_get_device_attr(busid_dev, "bNumInterfaces");

	if (!bConfValue || !bNumIntfs) {
		dbg("problem getting device attributes: %s",
		    strerror(errno));
		goto err_close_busid_dev;
	}

	for (i = 0; i < atoi(bNumIntfs->value); i++) {
		snprintf(intf_busid, SYSFS_BUS_ID_SIZE, "%s:%.1s.%d", busid,
			 bConfValue->value, i);

		rc = sysfs_write_attribute(bind_attr, intf_busid,
					   SYSFS_BUS_ID_SIZE);
		if (rc < 0) {
			dbg("bind driver at %s failed", intf_busid);
			failed = 1;
		}
	}

	if (!failed)
		ret = 0;

err_close_busid_dev:
	sysfs_close_device(busid_dev);
err_close_bind_attr:
	sysfs_close_attribute(bind_attr);

	return ret;
}

/* buggy driver may cause dead lock */
static int unbind_other(char *busid)
{
	char bus_type[] = "usb";
	char intf_busid[SYSFS_BUS_ID_SIZE];
	struct sysfs_device *busid_dev;
	struct sysfs_device *intf_dev;
	struct sysfs_driver *intf_drv;
	struct sysfs_attribute *unbind_attr;
	struct sysfs_attribute *bConfValue;
	struct sysfs_attribute *bDevClass;
	struct sysfs_attribute *bNumIntfs;
	int i, rc;
	enum unbind_status status = UNBIND_ST_OK;

	busid_dev = sysfs_open_device(bus_type, busid);
	if (!busid_dev) {
		dbg("sysfs_open_device %s failed: %s", busid, strerror(errno));
		return -1;
	}

	bConfValue = sysfs_get_device_attr(busid_dev, "bConfigurationValue");
	bDevClass  = sysfs_get_device_attr(busid_dev, "bDeviceClass");
	bNumIntfs  = sysfs_get_device_attr(busid_dev, "bNumInterfaces");
	if (!bConfValue || !bDevClass || !bNumIntfs) {
		dbg("problem getting device attributes: %s",
		    strerror(errno));
		goto err_close_busid_dev;
	}

	if (!strncmp(bDevClass->value, "09", bDevClass->len)) {
		dbg("skip unbinding of hub");
		goto err_close_busid_dev;
	}

	for (i = 0; i < atoi(bNumIntfs->value); i++) {
		snprintf(intf_busid, SYSFS_BUS_ID_SIZE, "%s:%.1s.%d", busid,
			 bConfValue->value, i);
		intf_dev = sysfs_open_device(bus_type, intf_busid);
		if (!intf_dev) {
			dbg("could not open interface device: %s",
			    strerror(errno));
			goto err_close_busid_dev;
		}

		dbg("%s -> %s", intf_dev->name,  intf_dev->driver_name);

		if (!strncmp("unknown", intf_dev->driver_name, SYSFS_NAME_LEN))
			/* unbound interface */
			continue;

		if (!strncmp(USBIP_HOST_DRV_NAME, intf_dev->driver_name,
			     SYSFS_NAME_LEN)) {
			/* already bound to usbip-host */
			status = UNBIND_ST_USBIP_HOST;
			continue;
		}

		/* unbinding */
		intf_drv = sysfs_open_driver(bus_type, intf_dev->driver_name);
		if (!intf_drv) {
			dbg("could not open interface driver on %s: %s",
			    intf_dev->name, strerror(errno));
			goto err_close_intf_dev;
		}

		unbind_attr = sysfs_get_driver_attr(intf_drv, "unbind");
		if (!unbind_attr) {
			dbg("problem getting interface driver attribute: %s",
			    strerror(errno));
			goto err_close_intf_drv;
		}

		rc = sysfs_write_attribute(unbind_attr, intf_dev->bus_id,
					   SYSFS_BUS_ID_SIZE);
		if (rc < 0) {
			/* NOTE: why keep unbinding other interfaces? */
			dbg("unbind driver at %s failed", intf_dev->bus_id);
			status = UNBIND_ST_FAILED;
		}

		sysfs_close_driver(intf_drv);
		sysfs_close_device(intf_dev);
	}

	goto out;

err_close_intf_drv:
	sysfs_close_driver(intf_drv);
err_close_intf_dev:
	sysfs_close_device(intf_dev);
err_close_busid_dev:
	status = UNBIND_ST_FAILED;
out:
	sysfs_close_device(busid_dev);

	return status;
}

static int bind_device(char *busid)
{
	int rc;

	rc = unbind_other(busid);
	if (rc == UNBIND_ST_FAILED) {
		err("could not unbind driver from device on busid %s", busid);
		return -1;
	} else if (rc == UNBIND_ST_USBIP_HOST) {
		err("device on busid %s is already bound to %s", busid,
		    USBIP_HOST_DRV_NAME);
		return -1;
	}

	rc = modify_match_busid(busid, 1);
	if (rc < 0) {
		err("unable to bind device on %s", busid);
		return -1;
	}

	rc = bind_usbip(busid);
	if (rc < 0) {
		err("could not bind device to %s", USBIP_HOST_DRV_NAME);
		modify_match_busid(busid, 0);
		return -1;
	}

	printf("bind device on busid %s: complete\n", busid);

	return 0;
}

int usbip_bind(int argc, char *argv[])
{
	static const struct option opts[] = {
		{ "busid", required_argument, NULL, 'b' },
		{ NULL,    0,                 NULL,  0  }
	};

	int opt;
	int ret = -1;

	for (;;) {
		opt = getopt_long(argc, argv, "b:", opts, NULL);

		if (opt == -1)
			break;

		switch (opt) {
		case 'b':
			ret = bind_device(optarg);
			goto out;
		default:
			goto err_out;
		}
	}

err_out:
	usbip_bind_usage();
out:
	return ret;
}