/*
 * virusb.c: helper APIs for managing host USB devices
 *
 * Copyright (C) 2009-2012 Red Hat, Inc.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library.  If not, see
 * <http://www.gnu.org/licenses/>.
 *
 * Authors:
 *     Daniel P. Berrange <berrange@redhat.com>
 */

#include <config.h>

#include <dirent.h>
#include <fcntl.h>
#include <inttypes.h>
#include <limits.h>
#include <stdio.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>

#include "virusb.h"
#include "virlog.h"
#include "viralloc.h"
#include "virutil.h"
#include "virerror.h"

#define USB_SYSFS "/sys/bus/usb"
#define USB_ID_LEN 10 /* "1234 5678" */
#define USB_ADDR_LEN 8 /* "123:456" */

/* For virReportOOMError()  and virReportSystemError() */
#define VIR_FROM_THIS VIR_FROM_NONE

struct _usbDevice {
    unsigned int      bus;
    unsigned int      dev;

    char          name[USB_ADDR_LEN]; /* domain:bus:slot.function */
    char          id[USB_ID_LEN];     /* product vendor */
    char          *path;
    const char    *used_by;           /* name of the domain using this dev */
};

struct _usbDeviceList {
    unsigned int count;
    usbDevice **devs;
};

typedef enum {
    USB_DEVICE_ALL = 0,
    USB_DEVICE_FIND_BY_VENDOR = 1 << 0,
    USB_DEVICE_FIND_BY_BUS = 1 << 1,
} usbDeviceFindFlags;

static int usbSysReadFile(const char *f_name, const char *d_name,
                          int base, unsigned int *value)
{
    int ret = -1, tmp;
    char *buf = NULL;
    char *filename = NULL;
    char *ignore = NULL;

    tmp = virAsprintf(&filename, USB_SYSFS "/devices/%s/%s", d_name, f_name);
    if (tmp < 0) {
        virReportOOMError();
        goto cleanup;
    }

    if (virFileReadAll(filename, 1024, &buf) < 0)
        goto cleanup;

    if (virStrToLong_ui(buf, &ignore, base, value) < 0) {
        virReportError(VIR_ERR_INTERNAL_ERROR,
                       _("Could not parse usb file %s"), filename);
        goto cleanup;
    }

    ret = 0;
cleanup:
    VIR_FREE(filename);
    VIR_FREE(buf);
    return ret;
}

static usbDeviceList *
usbDeviceSearch(unsigned int vendor,
                unsigned int product,
                unsigned int bus,
                unsigned int devno,
                const char *vroot,
                unsigned int flags)
{
    DIR *dir = NULL;
    bool found = false;
    char *ignore = NULL;
    struct dirent *de;
    usbDeviceList *list = NULL, *ret = NULL;
    usbDevice *usb;

    if (!(list = usbDeviceListNew()))
        goto cleanup;

    dir = opendir(USB_SYSFS "/devices");
    if (!dir) {
        virReportSystemError(errno,
                             _("Could not open directory %s"),
                             USB_SYSFS "/devices");
        goto cleanup;
    }

    while ((de = readdir(dir))) {
        unsigned int found_prod, found_vend, found_bus, found_devno;
        char *tmpstr = de->d_name;

        if (de->d_name[0] == '.' || strchr(de->d_name, ':'))
            continue;

        if (usbSysReadFile("idVendor", de->d_name,
                           16, &found_vend) < 0)
            goto cleanup;

        if (usbSysReadFile("idProduct", de->d_name,
                           16, &found_prod) < 0)
            goto cleanup;

        if (STRPREFIX(de->d_name, "usb"))
            tmpstr += 3;

        if (virStrToLong_ui(tmpstr, &ignore, 10, &found_bus) < 0) {
            virReportError(VIR_ERR_INTERNAL_ERROR,
                           _("Failed to parse dir name '%s'"),
                           de->d_name);
            goto cleanup;
        }

        if (usbSysReadFile("devnum", de->d_name,
                           10, &found_devno) < 0)
            goto cleanup;

        if ((flags & USB_DEVICE_FIND_BY_VENDOR) &&
            (found_prod != product || found_vend != vendor))
            continue;

        if (flags & USB_DEVICE_FIND_BY_BUS) {
            if (found_bus != bus || found_devno != devno)
                continue;
            found = true;
        }

        usb = usbGetDevice(found_bus, found_devno, vroot);
        if (!usb)
            goto cleanup;

        if (usbDeviceListAdd(list, usb) < 0) {
            usbFreeDevice(usb);
            goto cleanup;
        }

        if (found)
            break;
    }
    ret = list;

cleanup:
    if (dir) {
        int saved_errno = errno;
        closedir(dir);
        errno = saved_errno;
    }

    if (!ret)
        usbDeviceListFree(list);
    return ret;
}

int
usbFindDeviceByVendor(unsigned int vendor,
                      unsigned product,
                      const char *vroot,
                      bool mandatory,
                      usbDeviceList **devices)
{
    usbDeviceList *list;
    int count;

    if (!(list = usbDeviceSearch(vendor, product, 0 , 0,
                                 vroot,
                                 USB_DEVICE_FIND_BY_VENDOR)))
        return -1;

    if (list->count == 0) {
        usbDeviceListFree(list);
        if (!mandatory) {
            VIR_DEBUG("Did not find USB device %x:%x",
                      vendor, product);
            if (devices)
                *devices = NULL;
            return 0;
        }

        virReportError(VIR_ERR_INTERNAL_ERROR,
                       _("Did not find USB device %x:%x"), vendor, product);
        return -1;
    }

    count = list->count;
    if (devices)
        *devices = list;
    else
        usbDeviceListFree(list);

    return count;
}

int
usbFindDeviceByBus(unsigned int bus,
                   unsigned devno,
                   const char *vroot,
                   bool mandatory,
                   usbDevice **usb)
{
    usbDeviceList *list;

    if (!(list = usbDeviceSearch(0, 0, bus, devno,
                                 vroot,
                                 USB_DEVICE_FIND_BY_BUS)))
        return -1;

    if (list->count == 0) {
        usbDeviceListFree(list);
        if (!mandatory) {
            VIR_DEBUG("Did not find USB device bus:%u device:%u",
                      bus, devno);
            if (usb)
                *usb = NULL;
            return 0;
        }

        virReportError(VIR_ERR_INTERNAL_ERROR,
                       _("Did not find USB device bus:%u device:%u"),
                       bus, devno);
        return -1;
    }

    if (usb) {
        *usb = usbDeviceListGet(list, 0);
        usbDeviceListSteal(list, *usb);
    }
    usbDeviceListFree(list);

    return 0;
}

int
usbFindDevice(unsigned int vendor,
              unsigned int product,
              unsigned int bus,
              unsigned int devno,
              const char *vroot,
              bool mandatory,
              usbDevice **usb)
{
    usbDeviceList *list;

    unsigned int flags = USB_DEVICE_FIND_BY_VENDOR|USB_DEVICE_FIND_BY_BUS;
    if (!(list = usbDeviceSearch(vendor, product, bus, devno,
                                 vroot, flags)))
        return -1;

    if (list->count == 0) {
        usbDeviceListFree(list);
        if (!mandatory) {
            VIR_DEBUG("Did not find USB device %x:%x bus:%u device:%u",
                      vendor, product, bus, devno);
            if (usb)
                *usb = NULL;
            return 0;
        }

        virReportError(VIR_ERR_INTERNAL_ERROR,
                       _("Did not find USB device %x:%x bus:%u device:%u"),
                       vendor, product, bus, devno);
        return -1;
    }

    if (usb) {
        *usb = usbDeviceListGet(list, 0);
        usbDeviceListSteal(list, *usb);
    }
    usbDeviceListFree(list);

    return 0;
}

usbDevice *
usbGetDevice(unsigned int bus,
             unsigned int devno,
             const char *vroot)
{
    usbDevice *dev;

    if (VIR_ALLOC(dev) < 0) {
        virReportOOMError();
        return NULL;
    }

    dev->bus     = bus;
    dev->dev     = devno;

    if (snprintf(dev->name, sizeof(dev->name), "%.3o:%.3o",
                 dev->bus, dev->dev) >= sizeof(dev->name)) {
        virReportError(VIR_ERR_INTERNAL_ERROR,
                       _("dev->name buffer overflow: %.3o:%.3o"),
                       dev->bus, dev->dev);
        usbFreeDevice(dev);
        return NULL;
    }
    if (virAsprintf(&dev->path, "%s" USB_DEVFS "%03d/%03d",
                    vroot ? vroot : "",
                    dev->bus, dev->dev) < 0) {
        virReportOOMError();
        usbFreeDevice(dev);
        return NULL;
    }

    /* XXX fixme. this should be product/vendor */
    if (snprintf(dev->id, sizeof(dev->id), "%d %d", dev->bus,
                 dev->dev) >= sizeof(dev->id)) {
        virReportError(VIR_ERR_INTERNAL_ERROR,
                       _("dev->id buffer overflow: %d %d"),
                       dev->bus, dev->dev);
        usbFreeDevice(dev);
        return NULL;
    }

    VIR_DEBUG("%s %s: initialized", dev->id, dev->name);

    return dev;
}

void
usbFreeDevice(usbDevice *dev)
{
    if (!dev)
        return;
    VIR_DEBUG("%s %s: freeing", dev->id, dev->name);
    VIR_FREE(dev->path);
    VIR_FREE(dev);
}


void usbDeviceSetUsedBy(usbDevice *dev,
                        const char *name)
{
    dev->used_by = name;
}

const char * usbDeviceGetUsedBy(usbDevice *dev)
{
    return dev->used_by;
}

const char *usbDeviceGetName(usbDevice *dev)
{
    return dev->name;
}

unsigned int usbDeviceGetBus(usbDevice *dev)
{
    return dev->bus;
}


unsigned int usbDeviceGetDevno(usbDevice *dev)
{
    return dev->dev;
}


int usbDeviceFileIterate(usbDevice *dev,
                         usbDeviceFileActor actor,
                         void *opaque)
{
    return (actor)(dev, dev->path, opaque);
}

usbDeviceList *
usbDeviceListNew(void)
{
    usbDeviceList *list;

    if (VIR_ALLOC(list) < 0) {
        virReportOOMError();
        return NULL;
    }

    return list;
}

void
usbDeviceListFree(usbDeviceList *list)
{
    int i;

    if (!list)
        return;

    for (i = 0; i < list->count; i++)
        usbFreeDevice(list->devs[i]);

    VIR_FREE(list->devs);
    VIR_FREE(list);
}

int
usbDeviceListAdd(usbDeviceList *list,
                 usbDevice *dev)
{
    if (usbDeviceListFind(list, dev)) {
        virReportError(VIR_ERR_INTERNAL_ERROR,
                       _("Device %s is already in use"),
                       dev->name);
        return -1;
    }

    if (VIR_REALLOC_N(list->devs, list->count+1) < 0) {
        virReportOOMError();
        return -1;
    }

    list->devs[list->count++] = dev;

    return 0;
}

usbDevice *
usbDeviceListGet(usbDeviceList *list,
                 int idx)
{
    if (idx >= list->count ||
        idx < 0)
        return NULL;

    return list->devs[idx];
}

int
usbDeviceListCount(usbDeviceList *list)
{
    return list->count;
}

usbDevice *
usbDeviceListSteal(usbDeviceList *list,
                   usbDevice *dev)
{
    usbDevice *ret = NULL;
    int i;

    for (i = 0; i < list->count; i++) {
        if (list->devs[i]->bus != dev->bus ||
            list->devs[i]->dev != dev->dev)
            continue;

        ret = list->devs[i];

        if (i != list->count--)
            memmove(&list->devs[i],
                    &list->devs[i+1],
                    sizeof(*list->devs) * (list->count - i));

        if (VIR_REALLOC_N(list->devs, list->count) < 0) {
            ; /* not fatal */
        }

        break;
    }
    return ret;
}

void
usbDeviceListDel(usbDeviceList *list,
                 usbDevice *dev)
{
    usbDevice *ret = usbDeviceListSteal(list, dev);
    usbFreeDevice(ret);
}

usbDevice *
usbDeviceListFind(usbDeviceList *list,
                  usbDevice *dev)
{
    int i;

    for (i = 0; i < list->count; i++) {
        if (list->devs[i]->bus == dev->bus &&
            list->devs[i]->dev == dev->dev)
            return list->devs[i];
    }

    return NULL;
}