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/*
* Copyright (C) 2022 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#pragma once
#include <linux/netlink.h>
#include <sys/socket.h>
#include <cerrno>
#include <memory>
#include <optional>
#include <string>
#include "UniqueFd.h"
#include "log.h"
namespace android {
class UEvent {
public:
static auto CreateInstance() -> std::unique_ptr<UEvent> {
auto fd = UniqueFd(
socket(PF_NETLINK, SOCK_DGRAM | SOCK_CLOEXEC, NETLINK_KOBJECT_UEVENT));
if (!fd) {
ALOGE("Failed to open uevent socket: errno=%i", errno);
return {};
}
struct sockaddr_nl addr {};
addr.nl_family = AF_NETLINK;
addr.nl_pid = 0;
addr.nl_groups = UINT32_MAX;
// NOLINTNEXTLINE(cppcoreguidelines-pro-type-cstyle-cast)
int ret = bind(fd.Get(), (struct sockaddr *)&addr, sizeof(addr));
if (ret != 0) {
ALOGE("Failed to bind uevent socket: errno=%i", errno);
return {};
}
return std::unique_ptr<UEvent>(new UEvent(fd));
}
auto ReadNext() -> std::optional<std::string> {
constexpr int kUEventBufferSize = 1024;
char buffer[kUEventBufferSize];
ssize_t ret = 0;
ret = read(fd_.Get(), &buffer, sizeof(buffer));
if (ret == 0)
return {};
if (ret < 0) {
ALOGE("Got error reading uevent %zd", ret);
return {};
}
for (int i = 0; i < ret - 1; i++) {
if (buffer[i] == '\0') {
buffer[i] = '\n';
}
}
return std::string(buffer);
}
private:
explicit UEvent(UniqueFd &fd) : fd_(std::move(fd)){};
UniqueFd fd_;
};
} // namespace android
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