usbip_bind.c

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/*
 * Copyright (C) 2011 matt mooney <[email protected]>
 *               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;
}