minadbd/minadbd_services.cpp - android_bootable_recovery - Gitiles

 /*
  * Copyright (C) 2007 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.
  */

 #include "minadbd_services.h"

 #include <errno.h>
 #include <inttypes.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>

 #include <chrono>
 #include <functional>
 #include <memory>
 #include <set>
 #include <string>
 #include <string_view>
 #include <thread>

 #include <android-base/file.h>
 #include <android-base/logging.h>
 #include <android-base/memory.h>
 #include <android-base/parseint.h>
 #include <android-base/properties.h>
 #include <android-base/stringprintf.h>
 #include <android-base/strings.h>

 #include "adb.h"
 #include "adb_unique_fd.h"
 #include "adb_utils.h"
 #include "fuse_adb_provider.h"
 #include "fuse_sideload.h"
 #include "minadbd/types.h"
 #include "recovery_utils/battery_utils.h"
 #include "services.h"
 #include "sysdeps.h"

 static int minadbd_socket = -1;
 static bool rescue_mode = false;
 static std::string sideload_mount_point = FUSE_SIDELOAD_HOST_MOUNTPOINT;

 void SetMinadbdSocketFd(int socket_fd) {
   minadbd_socket = socket_fd;
 }

 void SetMinadbdRescueMode(bool rescue) {
   rescue_mode = rescue;
 }

 void SetSideloadMountPoint(const std::string& path) {
   sideload_mount_point = path;
 }

 static bool WriteCommandToFd(MinadbdCommand cmd, int fd) {
   char message[kMinadbdMessageSize];
   memcpy(message, kMinadbdCommandPrefix, strlen(kMinadbdStatusPrefix));
   android::base::put_unaligned(message + strlen(kMinadbdStatusPrefix), cmd);

   if (!android::base::WriteFully(fd, message, kMinadbdMessageSize)) {
     PLOG(ERROR) << "Failed to write message " << message;
     return false;
   }
   return true;
 }

 // Blocks and reads the command status from |fd|. Returns false if the received message has a
 // format error.
 static bool WaitForCommandStatus(int fd, MinadbdCommandStatus* status) {
   char buffer[kMinadbdMessageSize];
   if (!android::base::ReadFully(fd, buffer, kMinadbdMessageSize)) {
     PLOG(ERROR) << "Failed to response status from socket";
     exit(kMinadbdSocketIOError);
   }

   std::string message(buffer, buffer + kMinadbdMessageSize);
   if (!android::base::StartsWith(message, kMinadbdStatusPrefix)) {
     LOG(ERROR) << "Failed to parse status in " << message;
     return false;
   }

   *status = android::base::get_unaligned<MinadbdCommandStatus>(
       message.substr(strlen(kMinadbdStatusPrefix)).c_str());
   return true;
 }

 static MinadbdErrorCode RunAdbFuseSideload(int sfd, const std::string& args,
                                            MinadbdCommandStatus* status) {
   auto pieces = android::base::Split(args, ":");
   int64_t file_size;
   int block_size;
   if (pieces.size() != 2 || !android::base::ParseInt(pieces[0], &file_size) || file_size <= 0 ||
       !android::base::ParseInt(pieces[1], &block_size) || block_size <= 0) {
     LOG(ERROR) << "bad sideload-host arguments: " << args;
     return kMinadbdHostCommandArgumentError;
   }

   LOG(INFO) << "sideload-host file size " << file_size << ", block size " << block_size;

   if (!WriteCommandToFd(MinadbdCommand::kInstall, minadbd_socket)) {
     return kMinadbdSocketIOError;
   }

   auto adb_data_reader = std::make_unique<FuseAdbDataProvider>(sfd, file_size, block_size);
   if (int result = run_fuse_sideload(std::move(adb_data_reader), sideload_mount_point.c_str());
       result != 0) {
     LOG(ERROR) << "Failed to start fuse";
     return kMinadbdFuseStartError;
   }

   if (!WaitForCommandStatus(minadbd_socket, status)) {
     return kMinadbdMessageFormatError;
   }

   // Signal host-side adb to stop. For sideload mode, we always send kMinadbdServicesExitSuccess
   // (i.e. "DONEDONE") regardless of the install result. For rescue mode, we send failure message on
   // install error.
   if (!rescue_mode || *status == MinadbdCommandStatus::kSuccess) {
     if (!android::base::WriteFully(sfd, kMinadbdServicesExitSuccess,
                                    strlen(kMinadbdServicesExitSuccess))) {
       return kMinadbdHostSocketIOError;
     }
   } else {
     if (!android::base::WriteFully(sfd, kMinadbdServicesExitFailure,
                                    strlen(kMinadbdServicesExitFailure))) {
       return kMinadbdHostSocketIOError;
     }
   }

   return kMinadbdSuccess;
 }

 static bool WaitForSocketClose(int fd, std::chrono::milliseconds timeout) {
   const auto begin = std::chrono::steady_clock::now();
   const auto end = begin + timeout;
   while (std::chrono::steady_clock::now() < end) {
     // We don't care about reading the socket, we just want to wait until
     // socket closes. In this case .events = 0 will tell the kernel to wait
     // for close events.
     struct pollfd pfd = { .fd = fd, .events = 0 };
     auto timeout_ms = std::chrono::duration_cast<std::chrono::milliseconds>(
                           end - std::chrono::steady_clock::now())
                           .count();
     int rc = TEMP_FAILURE_RETRY(adb_poll(&pfd, 1, timeout_ms));
     if (rc == 1) {
       LOG(INFO) << "revents: " << pfd.revents;
       if (pfd.revents & (POLLHUP | POLLRDHUP)) {
         return true;
       }
     } else {
       PLOG(ERROR) << "poll() failed";
       // poll failed, almost definitely due to timeout
       // If not, you're screwed anyway, because it probably means the kernel ran
       // out of memory.
       return false;
     }
   }
   return false;
 }

 // Sideload service always exits after serving an install command.
 static void SideloadHostService(unique_fd sfd, const std::string& args) {
   using namespace std::chrono_literals;
   MinadbdCommandStatus status;
   auto error = RunAdbFuseSideload(sfd.get(), args, &status);
   // No need to wait if the socket is already closed, meaning the other end
   // already exited for some reason.
   if (error != kMinadbdHostSocketIOError) {
     // We sleep for a little bit just to wait for the host to receive last
     // "DONEDONE" message. However minadbd process is likely to get terminated
     // early due to exit_on_close
     WaitForSocketClose(sfd, 3000ms);
   }
   exit(error);
 }

 // Rescue service waits for the next command after an install command.
 static void RescueInstallHostService(unique_fd sfd, const std::string& args) {
   MinadbdCommandStatus status;
   if (auto result = RunAdbFuseSideload(sfd.get(), args, &status); result != kMinadbdSuccess) {
     exit(result);
   }
 }

 // Answers the query on a given property |prop|, by writing the result to the given |sfd|. The
 // result will be newline-terminated, so nonexistent or nonallowed query will be answered with "\n".
 // If given an empty string, dumps all the supported properties (analogous to `adb shell getprop`)
 // in lines, e.g. "[prop]: [value]".
 static void RescueGetpropHostService(unique_fd sfd, const std::string& prop) {
   constexpr const char* kRescueBatteryLevelProp = "rescue.battery_level";
   static const std::set<std::string> kGetpropAllowedProps = {
     // clang-format off
     kRescueBatteryLevelProp,
     "ro.build.date.utc",
     "ro.build.fingerprint",
     "ro.build.flavor",
     "ro.build.id",
     "ro.build.product",
     "ro.build.tags",
     "ro.build.version.incremental",
     "ro.product.device",
     "ro.product.vendor.device",
     // clang-format on
   };

   auto query_prop = [](const std::string& key) {
     if (key == kRescueBatteryLevelProp) {
       auto battery_info = GetBatteryInfo();
       return std::to_string(battery_info.capacity);
     }
     return android::base::GetProperty(key, "");
   };

   std::string result;
   if (prop.empty()) {
     for (const auto& key : kGetpropAllowedProps) {
       auto value = query_prop(key);
       if (value.empty()) {
         continue;
       }
       result += "[" + key + "]: [" + value + "]\n";
     }
   } else if (kGetpropAllowedProps.find(prop) != kGetpropAllowedProps.end()) {
     result = query_prop(prop) + "\n";
   }
   if (result.empty()) {
     result = "\n";
   }
   if (!android::base::WriteFully(sfd, result.data(), result.size())) {
     exit(kMinadbdHostSocketIOError);
   }

   // Send heartbeat signal to keep the rescue service alive.
   if (!WriteCommandToFd(MinadbdCommand::kNoOp, minadbd_socket)) {
     exit(kMinadbdSocketIOError);
   }
   if (MinadbdCommandStatus status; !WaitForCommandStatus(minadbd_socket, &status)) {
     exit(kMinadbdMessageFormatError);
   }
 }

 // Reboots into the given target. We don't reboot directly from minadbd, but going through recovery
 // instead. This allows recovery to finish all the pending works (clear BCB, save logs etc) before
 // the reboot.
 static void RebootHostService(unique_fd /* sfd */, const std::string& target) {
   MinadbdCommand command;
   if (target == "bootloader") {
     command = MinadbdCommand::kRebootBootloader;
   } else if (target == "rescue") {
     command = MinadbdCommand::kRebootRescue;
   } else if (target == "recovery") {
     command = MinadbdCommand::kRebootRecovery;
   } else if (target == "fastboot") {
     command = MinadbdCommand::kRebootFastboot;
   } else {
     command = MinadbdCommand::kRebootAndroid;
   }
   if (!WriteCommandToFd(command, minadbd_socket)) {
     exit(kMinadbdSocketIOError);
   }
   MinadbdCommandStatus status;
   if (!WaitForCommandStatus(minadbd_socket, &status)) {
     exit(kMinadbdMessageFormatError);
   }
 }

 static void WipeDeviceService(unique_fd fd, const std::string& args) {
   auto pieces = android::base::Split(args, ":");
   if (pieces.size() != 2 || pieces[0] != "userdata") {
     LOG(ERROR) << "Failed to parse wipe device command arguments " << args;
     exit(kMinadbdHostCommandArgumentError);
   }

   size_t message_size;
   if (!android::base::ParseUint(pieces[1], &message_size) ||
       message_size < strlen(kMinadbdServicesExitSuccess)) {
     LOG(ERROR) << "Failed to parse wipe device message size in " << args;
     exit(kMinadbdHostCommandArgumentError);
   }

   WriteCommandToFd(MinadbdCommand::kWipeData, minadbd_socket);
   MinadbdCommandStatus status;
   if (!WaitForCommandStatus(minadbd_socket, &status)) {
     exit(kMinadbdMessageFormatError);
   }

   std::string response = (status == MinadbdCommandStatus::kSuccess) ? kMinadbdServicesExitSuccess
                                                                     : kMinadbdServicesExitFailure;
   response += std::string(message_size - response.size(), '\0');
   if (!android::base::WriteFully(fd, response.c_str(), response.size())) {
     exit(kMinadbdHostSocketIOError);
   }
 }

 asocket* daemon_service_to_socket(std::string_view) {
   return nullptr;
 }

 unique_fd daemon_service_to_fd(std::string_view name, atransport* /* transport */) {
   // Common services that are supported both in sideload and rescue modes.
   if (android::base::ConsumePrefix(&name, "reboot:")) {
     // "reboot:<target>", where target must be one of the following.
     std::string args(name);
     if (args.empty() || args == "bootloader" || args == "rescue" || args == "recovery" ||
         args == "fastboot") {
       return create_service_thread("reboot",
                                    std::bind(RebootHostService, std::placeholders::_1, args));
     }
     return unique_fd{};
   }

   // Rescue-specific services.
   if (rescue_mode) {
     if (android::base::ConsumePrefix(&name, "rescue-install:")) {
       // rescue-install:<file-size>:<block-size>
       std::string args(name);
       return create_service_thread(
           "rescue-install", std::bind(RescueInstallHostService, std::placeholders::_1, args));
     } else if (android::base::ConsumePrefix(&name, "rescue-getprop:")) {
       // rescue-getprop:<prop>
       std::string args(name);
       return create_service_thread(
           "rescue-getprop", std::bind(RescueGetpropHostService, std::placeholders::_1, args));
     } else if (android::base::ConsumePrefix(&name, "rescue-wipe:")) {
       // rescue-wipe:target:<message-size>
       std::string args(name);
       return create_service_thread("rescue-wipe",
                                    std::bind(WipeDeviceService, std::placeholders::_1, args));
     }

     return unique_fd{};
   }

   // Sideload-specific services.
   if (name.starts_with("sideload:")) {
     // This exit status causes recovery to print a special error message saying to use a newer adb
     // (that supports sideload-host).
     exit(kMinadbdAdbVersionError);
   } else if (android::base::ConsumePrefix(&name, "sideload-host:")) {
     // sideload-host:<file-size>:<block-size>
     std::string args(name);
     return create_service_thread("sideload-host",
                                  std::bind(SideloadHostService, std::placeholders::_1, args));
   }
   return unique_fd{};
 }
	/*
	* Copyright (C) 2007 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.
	*/

	#include "minadbd_services.h"

	#include <errno.h>
	#include <inttypes.h>
	#include <stdio.h>
	#include <stdlib.h>
	#include <string.h>
	#include <unistd.h>

	#include <chrono>
	#include <functional>
	#include <memory>
	#include <set>
	#include <string>
	#include <string_view>
	#include <thread>

	#include <android-base/file.h>
	#include <android-base/logging.h>
	#include <android-base/memory.h>
	#include <android-base/parseint.h>
	#include <android-base/properties.h>
	#include <android-base/stringprintf.h>
	#include <android-base/strings.h>

	#include "adb.h"
	#include "adb_unique_fd.h"
	#include "adb_utils.h"
	#include "fuse_adb_provider.h"
	#include "fuse_sideload.h"
	#include "minadbd/types.h"
	#include "recovery_utils/battery_utils.h"
	#include "services.h"
	#include "sysdeps.h"

	static int minadbd_socket = -1;
	static bool rescue_mode = false;
	static std::string sideload_mount_point = FUSE_SIDELOAD_HOST_MOUNTPOINT;

	void SetMinadbdSocketFd(int socket_fd) {
	minadbd_socket = socket_fd;
	}

	void SetMinadbdRescueMode(bool rescue) {
	rescue_mode = rescue;
	}

	void SetSideloadMountPoint(const std::string& path) {
	sideload_mount_point = path;
	}

	static bool WriteCommandToFd(MinadbdCommand cmd, int fd) {
	char message[kMinadbdMessageSize];
	memcpy(message, kMinadbdCommandPrefix, strlen(kMinadbdStatusPrefix));
	android::base::put_unaligned(message + strlen(kMinadbdStatusPrefix), cmd);

	if (!android::base::WriteFully(fd, message, kMinadbdMessageSize)) {
	PLOG(ERROR) << "Failed to write message " << message;
	return false;
	}
	return true;
	}

	// Blocks and reads the command status from \|fd\|. Returns false if the received message has a
	// format error.
	static bool WaitForCommandStatus(int fd, MinadbdCommandStatus* status) {
	char buffer[kMinadbdMessageSize];
	if (!android::base::ReadFully(fd, buffer, kMinadbdMessageSize)) {
	PLOG(ERROR) << "Failed to response status from socket";
	exit(kMinadbdSocketIOError);
	}

	std::string message(buffer, buffer + kMinadbdMessageSize);
	if (!android::base::StartsWith(message, kMinadbdStatusPrefix)) {
	LOG(ERROR) << "Failed to parse status in " << message;
	return false;
	}

	*status = android::base::get_unaligned<MinadbdCommandStatus>(
	message.substr(strlen(kMinadbdStatusPrefix)).c_str());
	return true;
	}

	static MinadbdErrorCode RunAdbFuseSideload(int sfd, const std::string& args,
	MinadbdCommandStatus* status) {
	auto pieces = android::base::Split(args, ":");
	int64_t file_size;
	int block_size;
	if (pieces.size() != 2 \|\| !android::base::ParseInt(pieces[0], &file_size) \|\| file_size <= 0 \|\|
	!android::base::ParseInt(pieces[1], &block_size) \|\| block_size <= 0) {
	LOG(ERROR) << "bad sideload-host arguments: " << args;
	return kMinadbdHostCommandArgumentError;
	}

	LOG(INFO) << "sideload-host file size " << file_size << ", block size " << block_size;

	if (!WriteCommandToFd(MinadbdCommand::kInstall, minadbd_socket)) {
	return kMinadbdSocketIOError;
	}

	auto adb_data_reader = std::make_unique<FuseAdbDataProvider>(sfd, file_size, block_size);
	if (int result = run_fuse_sideload(std::move(adb_data_reader), sideload_mount_point.c_str());
	result != 0) {
	LOG(ERROR) << "Failed to start fuse";
	return kMinadbdFuseStartError;
	}

	if (!WaitForCommandStatus(minadbd_socket, status)) {
	return kMinadbdMessageFormatError;
	}

	// Signal host-side adb to stop. For sideload mode, we always send kMinadbdServicesExitSuccess
	// (i.e. "DONEDONE") regardless of the install result. For rescue mode, we send failure message on
	// install error.
	if (!rescue_mode \|\| *status == MinadbdCommandStatus::kSuccess) {
	if (!android::base::WriteFully(sfd, kMinadbdServicesExitSuccess,
	strlen(kMinadbdServicesExitSuccess))) {
	return kMinadbdHostSocketIOError;
	}
	} else {
	if (!android::base::WriteFully(sfd, kMinadbdServicesExitFailure,
	strlen(kMinadbdServicesExitFailure))) {
	return kMinadbdHostSocketIOError;
	}
	}

	return kMinadbdSuccess;
	}

	static bool WaitForSocketClose(int fd, std::chrono::milliseconds timeout) {
	const auto begin = std::chrono::steady_clock::now();
	const auto end = begin + timeout;
	while (std::chrono::steady_clock::now() < end) {
	// We don't care about reading the socket, we just want to wait until
	// socket closes. In this case .events = 0 will tell the kernel to wait
	// for close events.
	struct pollfd pfd = { .fd = fd, .events = 0 };
	auto timeout_ms = std::chrono::duration_cast<std::chrono::milliseconds>(
	end - std::chrono::steady_clock::now())
	.count();
	int rc = TEMP_FAILURE_RETRY(adb_poll(&pfd, 1, timeout_ms));
	if (rc == 1) {
	LOG(INFO) << "revents: " << pfd.revents;
	if (pfd.revents & (POLLHUP \| POLLRDHUP)) {
	return true;
	}
	} else {
	PLOG(ERROR) << "poll() failed";
	// poll failed, almost definitely due to timeout
	// If not, you're screwed anyway, because it probably means the kernel ran
	// out of memory.
	return false;
	}
	}
	return false;
	}

	// Sideload service always exits after serving an install command.
	static void SideloadHostService(unique_fd sfd, const std::string& args) {
	using namespace std::chrono_literals;
	MinadbdCommandStatus status;
	auto error = RunAdbFuseSideload(sfd.get(), args, &status);
	// No need to wait if the socket is already closed, meaning the other end
	// already exited for some reason.
	if (error != kMinadbdHostSocketIOError) {
	// We sleep for a little bit just to wait for the host to receive last
	// "DONEDONE" message. However minadbd process is likely to get terminated
	// early due to exit_on_close
	WaitForSocketClose(sfd, 3000ms);
	}
	exit(error);
	}

	// Rescue service waits for the next command after an install command.
	static void RescueInstallHostService(unique_fd sfd, const std::string& args) {
	MinadbdCommandStatus status;
	if (auto result = RunAdbFuseSideload(sfd.get(), args, &status); result != kMinadbdSuccess) {
	exit(result);
	}
	}

	// Answers the query on a given property \|prop\|, by writing the result to the given \|sfd\|. The
	// result will be newline-terminated, so nonexistent or nonallowed query will be answered with "\n".
	// If given an empty string, dumps all the supported properties (analogous to `adb shell getprop`)
	// in lines, e.g. "[prop]: [value]".
	static void RescueGetpropHostService(unique_fd sfd, const std::string& prop) {
	constexpr const char* kRescueBatteryLevelProp = "rescue.battery_level";
	static const std::set<std::string> kGetpropAllowedProps = {
	// clang-format off
	kRescueBatteryLevelProp,
	"ro.build.date.utc",
	"ro.build.fingerprint",
	"ro.build.flavor",
	"ro.build.id",
	"ro.build.product",
	"ro.build.tags",
	"ro.build.version.incremental",
	"ro.product.device",
	"ro.product.vendor.device",
	// clang-format on
	};

	auto query_prop = [](const std::string& key) {
	if (key == kRescueBatteryLevelProp) {
	auto battery_info = GetBatteryInfo();
	return std::to_string(battery_info.capacity);
	}
	return android::base::GetProperty(key, "");
	};

	std::string result;
	if (prop.empty()) {
	for (const auto& key : kGetpropAllowedProps) {
	auto value = query_prop(key);
	if (value.empty()) {
	continue;
	}
	result += "[" + key + "]: [" + value + "]\n";
	}
	} else if (kGetpropAllowedProps.find(prop) != kGetpropAllowedProps.end()) {
	result = query_prop(prop) + "\n";
	}
	if (result.empty()) {
	result = "\n";
	}
	if (!android::base::WriteFully(sfd, result.data(), result.size())) {
	exit(kMinadbdHostSocketIOError);
	}

	// Send heartbeat signal to keep the rescue service alive.
	if (!WriteCommandToFd(MinadbdCommand::kNoOp, minadbd_socket)) {
	exit(kMinadbdSocketIOError);
	}
	if (MinadbdCommandStatus status; !WaitForCommandStatus(minadbd_socket, &status)) {
	exit(kMinadbdMessageFormatError);
	}
	}

	// Reboots into the given target. We don't reboot directly from minadbd, but going through recovery
	// instead. This allows recovery to finish all the pending works (clear BCB, save logs etc) before
	// the reboot.
	static void RebootHostService(unique_fd /* sfd */, const std::string& target) {
	MinadbdCommand command;
	if (target == "bootloader") {
	command = MinadbdCommand::kRebootBootloader;
	} else if (target == "rescue") {
	command = MinadbdCommand::kRebootRescue;
	} else if (target == "recovery") {
	command = MinadbdCommand::kRebootRecovery;
	} else if (target == "fastboot") {
	command = MinadbdCommand::kRebootFastboot;
	} else {
	command = MinadbdCommand::kRebootAndroid;
	}
	if (!WriteCommandToFd(command, minadbd_socket)) {
	exit(kMinadbdSocketIOError);
	}
	MinadbdCommandStatus status;
	if (!WaitForCommandStatus(minadbd_socket, &status)) {
	exit(kMinadbdMessageFormatError);
	}
	}

	static void WipeDeviceService(unique_fd fd, const std::string& args) {
	auto pieces = android::base::Split(args, ":");
	if (pieces.size() != 2 \|\| pieces[0] != "userdata") {
	LOG(ERROR) << "Failed to parse wipe device command arguments " << args;
	exit(kMinadbdHostCommandArgumentError);
	}

	size_t message_size;
	if (!android::base::ParseUint(pieces[1], &message_size) \|\|
	message_size < strlen(kMinadbdServicesExitSuccess)) {
	LOG(ERROR) << "Failed to parse wipe device message size in " << args;
	exit(kMinadbdHostCommandArgumentError);
	}

	WriteCommandToFd(MinadbdCommand::kWipeData, minadbd_socket);
	MinadbdCommandStatus status;
	if (!WaitForCommandStatus(minadbd_socket, &status)) {
	exit(kMinadbdMessageFormatError);
	}

	std::string response = (status == MinadbdCommandStatus::kSuccess) ? kMinadbdServicesExitSuccess
	: kMinadbdServicesExitFailure;
	response += std::string(message_size - response.size(), '\0');
	if (!android::base::WriteFully(fd, response.c_str(), response.size())) {
	exit(kMinadbdHostSocketIOError);
	}
	}

	asocket* daemon_service_to_socket(std::string_view) {
	return nullptr;
	}

	unique_fd daemon_service_to_fd(std::string_view name, atransport* /* transport */) {
	// Common services that are supported both in sideload and rescue modes.
	if (android::base::ConsumePrefix(&name, "reboot:")) {
	// "reboot:<target>", where target must be one of the following.
	std::string args(name);
	if (args.empty() \|\| args == "bootloader" \|\| args == "rescue" \|\| args == "recovery" \|\|
	args == "fastboot") {
	return create_service_thread("reboot",
	std::bind(RebootHostService, std::placeholders::_1, args));
	}
	return unique_fd{};
	}

	// Rescue-specific services.
	if (rescue_mode) {
	if (android::base::ConsumePrefix(&name, "rescue-install:")) {
	// rescue-install:<file-size>:<block-size>
	std::string args(name);
	return create_service_thread(
	"rescue-install", std::bind(RescueInstallHostService, std::placeholders::_1, args));
	} else if (android::base::ConsumePrefix(&name, "rescue-getprop:")) {
	// rescue-getprop:<prop>
	std::string args(name);
	return create_service_thread(
	"rescue-getprop", std::bind(RescueGetpropHostService, std::placeholders::_1, args));
	} else if (android::base::ConsumePrefix(&name, "rescue-wipe:")) {
	// rescue-wipe:target:<message-size>
	std::string args(name);
	return create_service_thread("rescue-wipe",
	std::bind(WipeDeviceService, std::placeholders::_1, args));
	}

	return unique_fd{};
	}

	// Sideload-specific services.
	if (name.starts_with("sideload:")) {
	// This exit status causes recovery to print a special error message saying to use a newer adb
	// (that supports sideload-host).
	exit(kMinadbdAdbVersionError);
	} else if (android::base::ConsumePrefix(&name, "sideload-host:")) {
	// sideload-host:<file-size>:<block-size>
	std::string args(name);
	return create_service_thread("sideload-host",
	std::bind(SideloadHostService, std::placeholders::_1, args));
	}
	return unique_fd{};
	}