/*
 * Copyright (C) 2015-2016 Samsung Electronics
 *               Igor Kotrasinski <i.kotrasinsk@samsung.com>
 *               Krzysztof Opasiak <k.opasiak@samsung.com>
 *
 * Refactored from usbip_host_driver.c, which is:
 * 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 <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>

#include <errno.h>
#include <unistd.h>

#include <libudev.h>

#include "usbip_common.h"
#include "usbip_host_common.h"
#include "list.h"
#include "sysfs_utils.h"

struct udev *udev_context;

static int32_t read_attr_usbip_status(struct usbip_usb_device *udev)
{
        char status_attr_path[SYSFS_PATH_MAX];
        int size;
        int fd;
        int length;
        char status;
        int value = 0;

        size = snprintf(status_attr_path, sizeof(status_attr_path),
                        "%s/usbip_status", udev->path);
        if (size < 0 || (unsigned int)size >= sizeof(status_attr_path)) {
                err("usbip_status path length %i >= %lu or < 0", size,
                    (long unsigned)sizeof(status_attr_path));
                return -1;
        }


        fd = open(status_attr_path, O_RDONLY);
        if (fd < 0) {
                err("error opening attribute %s", status_attr_path);
                return -1;
        }

        length = read(fd, &status, 1);
        if (length < 0) {
                err("error reading attribute %s", status_attr_path);
                close(fd);
                return -1;
        }

        value = atoi(&status);

        return value;
}

static
struct usbip_exported_device *usbip_exported_device_new(
                struct usbip_host_driver *hdriver, const char *sdevpath)
{
        struct usbip_exported_device *edev = NULL;
        struct usbip_exported_device *edev_old;
        size_t size;
        int i;

        edev = calloc(1, sizeof(struct usbip_exported_device));

        edev->sudev =
                udev_device_new_from_syspath(udev_context, sdevpath);
        if (!edev->sudev) {
                err("udev_device_new_from_syspath: %s", sdevpath);
                goto err;
        }

        if (hdriver->ops.read_device(edev->sudev, &edev->udev) < 0)
                goto err;

        edev->status = read_attr_usbip_status(&edev->udev);
        if (edev->status < 0)
                goto err;

        /* reallocate buffer to include usb interface data */
        size = sizeof(struct usbip_exported_device) +
                edev->udev.bNumInterfaces * sizeof(struct usbip_usb_interface);

        edev_old = edev;
        edev = realloc(edev, size);
        if (!edev) {
                edev = edev_old;
                dbg("realloc failed");
                goto err;
        }

        for (i = 0; i < edev->udev.bNumInterfaces; i++) {
                /* vudc does not support reading interfaces */
                if (!hdriver->ops.read_interface)
                        break;
                hdriver->ops.read_interface(&edev->udev, i, &edev->uinf[i]);
        }

        return edev;
err:
        if (edev->sudev)
                udev_device_unref(edev->sudev);
        if (edev)
                free(edev);

        return NULL;
}

static int refresh_exported_devices(struct usbip_host_driver *hdriver)
{
        struct usbip_exported_device *edev;
        struct udev_enumerate *enumerate;
        struct udev_list_entry *devices, *dev_list_entry;
        struct udev_device *dev;
        const char *path;

        enumerate = udev_enumerate_new(udev_context);
        udev_enumerate_add_match_subsystem(enumerate, hdriver->udev_subsystem);
        udev_enumerate_scan_devices(enumerate);

        devices = udev_enumerate_get_list_entry(enumerate);

        udev_list_entry_foreach(dev_list_entry, devices) {
                path = udev_list_entry_get_name(dev_list_entry);
                dev = udev_device_new_from_syspath(udev_context,
                                                   path);
                if (dev == NULL)
                        continue;

                /* Check whether device uses usbip driver. */
                if (hdriver->ops.is_my_device(dev)) {
                        edev = usbip_exported_device_new(hdriver, path);
                        if (!edev) {
                                dbg("usbip_exported_device_new failed");
                                continue;
                        }

                        list_add(&edev->node, &hdriver->edev_list);
                        hdriver->ndevs++;
                }
        }

        return 0;
}

static void usbip_exported_device_destroy(struct list_head *devs)
{
        struct list_head *i, *tmp;
        struct usbip_exported_device *edev;

        list_for_each_safe(i, tmp, devs) {
                edev = list_entry(i, struct usbip_exported_device, node);
                list_del(i);
                free(edev);
        }
}

int usbip_generic_driver_open(struct usbip_host_driver *hdriver)
{
        int rc;

        udev_context = udev_new();
        if (!udev_context) {
                err("udev_new failed");
                return -1;
        }

        rc = refresh_exported_devices(hdriver);
        if (rc < 0)
                goto err;
        return 0;
err:
        udev_unref(udev_context);
        return -1;
}

void usbip_generic_driver_close(struct usbip_host_driver *hdriver)
{
        if (!hdriver)
                return;

        usbip_exported_device_destroy(&hdriver->edev_list);

        udev_unref(udev_context);
}

int usbip_generic_refresh_device_list(struct usbip_host_driver *hdriver)
{
        int rc;

        usbip_exported_device_destroy(&hdriver->edev_list);

        hdriver->ndevs = 0;
        INIT_LIST_HEAD(&hdriver->edev_list);

        rc = refresh_exported_devices(hdriver);
        if (rc < 0)
                return -1;

        return 0;
}

int usbip_export_device(struct usbip_exported_device *edev, int sockfd)
{
        char attr_name[] = "usbip_sockfd";
        char sockfd_attr_path[SYSFS_PATH_MAX];
        int size;
        char sockfd_buff[30];
        int ret;

        if (edev->status != SDEV_ST_AVAILABLE) {
                dbg("device not available: %s", edev->udev.busid);
                switch (edev->status) {
                case SDEV_ST_ERROR:
                        dbg("status SDEV_ST_ERROR");
                        break;
                case SDEV_ST_USED:
                        dbg("status SDEV_ST_USED");
                        break;
                default:
                        dbg("status unknown: 0x%x", edev->status);
                }
                return -1;
        }

        /* only the first interface is true */
        size = snprintf(sockfd_attr_path, sizeof(sockfd_attr_path), "%s/%s",
                        edev->udev.path, attr_name);
        if (size < 0 || (unsigned int)size >= sizeof(sockfd_attr_path)) {
                err("exported device path length %i >= %lu or < 0", size,
                    (long unsigned)sizeof(sockfd_attr_path));
                return -1;
        }

        size = snprintf(sockfd_buff, sizeof(sockfd_buff), "%d\n", sockfd);
        if (size < 0 || (unsigned int)size >= sizeof(sockfd_buff)) {
                err("socket length %i >= %lu or < 0", size,
                    (long unsigned)sizeof(sockfd_buff));
                return -1;
        }

        ret = write_sysfs_attribute(sockfd_attr_path, sockfd_buff,
                                    strlen(sockfd_buff));
        if (ret < 0) {
                err("write_sysfs_attribute failed: sockfd %s to %s",
                    sockfd_buff, sockfd_attr_path);
                return ret;
        }

        info("connect: %s", edev->udev.busid);

        return ret;
}

struct usbip_exported_device *usbip_generic_get_device(
                struct usbip_host_driver *hdriver, int num)
{
        struct list_head *i;
        struct usbip_exported_device *edev;
        int cnt = 0;

        list_for_each(i, &hdriver->edev_list) {
                edev = list_entry(i, struct usbip_exported_device, node);
                if (num == cnt)
                        return edev;
                cnt++;
        }

        return NULL;
}