blob: f3cddfd86895e1a329506fa70166672ee84f9e9a [file] [log] [blame]
// Copyright (c) 2012 The Chromium OS Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "permission_broker/deny_claimed_usb_device_rule.h"
#include <libudev.h>
#include "base/logging.h"
#include "base/string_number_conversions.h"
namespace permission_broker {
DenyClaimedUsbDeviceRule::DenyClaimedUsbDeviceRule()
: Rule("DenyClaimedUsbDeviceRule"), udev_(udev_new()) {}
DenyClaimedUsbDeviceRule::~DenyClaimedUsbDeviceRule() {
udev_unref(udev_);
}
Rule::Result DenyClaimedUsbDeviceRule::Process(const std::string &path,
int interface_id) {
struct udev_enumerate *enumerate = udev_enumerate_new(udev_);
udev_enumerate_scan_devices(enumerate);
bool deny = false;
struct udev_list_entry *entry = NULL;
udev_list_entry_foreach(entry, udev_enumerate_get_list_entry(enumerate)) {
const char *entry_path = udev_list_entry_get_name(entry);
struct udev_device *device = udev_device_new_from_syspath(udev_,
entry_path);
// usb_interface entries--direct descendants of usb_device entires--are not,
// for the purposes of this rule, considered as having claimed the device.
const char *device_type = udev_device_get_devtype(device);
if (device_type &&
!strcmp(device_type, "usb_interface") &&
interface_id == ANY_INTERFACE) {
udev_device_unref(device);
continue;
}
struct udev_device *parent = udev_device_get_parent_with_subsystem_devtype(
device, "usb", "usb_device");
if (parent && (path == udev_device_get_devnode(parent))) {
deny = true;
// Check if the specific interface is already claimed (has driver).
if (interface_id != ANY_INTERFACE) {
const char* driver = udev_device_get_driver(device);
if (!driver) {
const char* interface_num = udev_device_get_sysattr_value(
device, "bInterfaceNumber");
int interface_value;
if (interface_num &&
base::HexStringToInt(interface_num, &interface_value) &&
interface_value == interface_id) {
deny = false;
udev_device_unref(device);
break;
}
}
}
}
udev_device_unref(device);
}
udev_enumerate_unref(enumerate);
if (deny)
return DENY;
return IGNORE;
}
} // namespace permission_broker