// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright (C) 2011 matt mooney <mfm@muteddisk.com>
 *               2005-2007 Takahiro Hirofuchi
 */

#include <libudev.h>

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

#include <getopt.h>

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

static const char usbip_unbind_usage_string[] =
        "usbip unbind <args>\n"
        "    -b, --busid=<busid>    Unbind " USBIP_HOST_DRV_NAME ".ko from "
        "device on <busid>\n";

void usbip_unbind_usage(void)
{
        printf("usage: %s", usbip_unbind_usage_string);
}

static int unbind_device(char *busid)
{
        char bus_type[] = "usb";
        int rc, ret = -1;

        char unbind_attr_name[] = "unbind";
        char unbind_attr_path[SYSFS_PATH_MAX];
        char rebind_attr_name[] = "rebind";
        char rebind_attr_path[SYSFS_PATH_MAX];

        struct udev *udev;
        struct udev_device *dev;
        const char *driver;

        /* Create libudev context. */
        udev = udev_new();

        /* Check whether the device with this bus ID exists. */
        dev = udev_device_new_from_subsystem_sysname(udev, "usb", busid);
        if (!dev) {
                err("device with the specified bus ID does not exist");
                goto err_close_udev;
        }

        /* Check whether the device is using usbip-host driver. */
        driver = udev_device_get_driver(dev);
        if (!driver || strcmp(driver, "usbip-host")) {
                err("device is not bound to usbip-host driver");
                goto err_close_udev;
        }

        /* Unbind device from driver. */
        snprintf(unbind_attr_path, sizeof(unbind_attr_path), "%s/%s/%s/%s/%s/%s",
                 SYSFS_MNT_PATH, SYSFS_BUS_NAME, bus_type, SYSFS_DRIVERS_NAME,
                 USBIP_HOST_DRV_NAME, unbind_attr_name);

        rc = write_sysfs_attribute(unbind_attr_path, busid, strlen(busid));
        if (rc < 0) {
                err("error unbinding device %s from driver", busid);
                goto err_close_udev;
        }

        /* Notify driver of unbind. */
        rc = modify_match_busid(busid, 0);
        if (rc < 0) {
                err("unable to unbind device on %s", busid);
                goto err_close_udev;
        }

        /* Trigger new probing. */
        snprintf(rebind_attr_path, sizeof(unbind_attr_path), "%s/%s/%s/%s/%s/%s",
                        SYSFS_MNT_PATH, SYSFS_BUS_NAME, bus_type, SYSFS_DRIVERS_NAME,
                        USBIP_HOST_DRV_NAME, rebind_attr_name);

        rc = write_sysfs_attribute(rebind_attr_path, busid, strlen(busid));
        if (rc < 0) {
                err("error rebinding");
                goto err_close_udev;
        }

        ret = 0;
        info("unbind device on busid %s: complete", busid);

err_close_udev:
        udev_device_unref(dev);
        udev_unref(udev);

        return ret;
}

int usbip_unbind(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 = unbind_device(optarg);
                        goto out;
                default:
                        goto err_out;
                }
        }

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