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Diffstat (limited to 'utils/UEvent.h')
-rw-r--r-- | utils/UEvent.h | 85 |
1 files changed, 85 insertions, 0 deletions
diff --git a/utils/UEvent.h b/utils/UEvent.h new file mode 100644 index 0000000..17b3cab --- /dev/null +++ b/utils/UEvent.h @@ -0,0 +1,85 @@ +/* + * 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 |