/*
 * Copyright (C) 2018 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.
 */

#define TRACE_TAG SERVICES

#include "sysdeps.h"

#include <errno.h>
#include <netdb.h>
#include <netinet/in.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <unistd.h>

#include <thread>

#include <android-base/file.h>
#include <android-base/parseint.h>
#include <android-base/parsenetaddress.h>
#include <android-base/properties.h>
#include <android-base/stringprintf.h>
#include <android-base/strings.h>
#include <android-base/unique_fd.h>
#include <cutils/sockets.h>
#include <log/log_properties.h>

#include "adb.h"
#include "adb_io.h"
#include "adb_unique_fd.h"
#include "adb_utils.h"
#include "services.h"
#include "socket_spec.h"
#include "sysdeps.h"
#include "transport.h"

#include "daemon/file_sync_service.h"
#include "daemon/framebuffer_service.h"
#include "daemon/reboot_service.h"
#include "daemon/remount_service.h"
#include "daemon/restart_service.h"
#include "daemon/set_verity_enable_state_service.h"
#include "daemon/shell_service.h"


void reconnect_service(unique_fd fd, atransport* t) {
    WriteFdExactly(fd.get(), "done");
    kick_transport(t);
}

unique_fd reverse_service(std::string_view command, atransport* transport) {
    // TODO: Switch handle_forward_request to std::string_view.
    std::string str(command);

    int s[2];
    if (adb_socketpair(s)) {
        PLOG(ERROR) << "cannot create service socket pair.";
        return unique_fd{};
    }
    VLOG(SERVICES) << "service socketpair: " << s[0] << ", " << s[1];
    if (!handle_forward_request(str.c_str(), transport, s[1])) {
        SendFail(s[1], "not a reverse forwarding command");
    }
    adb_close(s[1]);
    return unique_fd{s[0]};
}

// Shell service string can look like:
//   shell[,arg1,arg2,...]:[command]
unique_fd ShellService(std::string_view args, const atransport* transport) {
    size_t delimiter_index = args.find(':');
    if (delimiter_index == std::string::npos) {
        LOG(ERROR) << "No ':' found in shell service arguments: " << args;
        return unique_fd{};
    }

    // TODO: android::base::Split(const std::string_view&, ...)
    std::string service_args(args.substr(0, delimiter_index));
    std::string command(args.substr(delimiter_index + 1));

    // Defaults:
    //   PTY for interactive, raw for non-interactive.
    //   No protocol.
    //   $TERM set to "dumb".
    SubprocessType type(command.empty() ? SubprocessType::kPty : SubprocessType::kRaw);
    SubprocessProtocol protocol = SubprocessProtocol::kNone;
    std::string terminal_type = "dumb";

    for (const std::string& arg : android::base::Split(service_args, ",")) {
        if (arg == kShellServiceArgRaw) {
            type = SubprocessType::kRaw;
        } else if (arg == kShellServiceArgPty) {
            type = SubprocessType::kPty;
        } else if (arg == kShellServiceArgShellProtocol) {
            protocol = SubprocessProtocol::kShell;
        } else if (arg.starts_with("TERM=")) {
            terminal_type = arg.substr(strlen("TERM="));
        } else if (!arg.empty()) {
            // This is not an error to allow for future expansion.
            LOG(WARNING) << "Ignoring unknown shell service argument: " << arg;
        }
    }

    return StartSubprocess(command, terminal_type.c_str(), type, protocol);
}

static void spin_service(unique_fd fd) {
    if (!__android_log_is_debuggable()) {
        WriteFdExactly(fd.get(), "refusing to spin on non-debuggable build\n");
        return;
    }

    // A service that creates an fdevent that's always pending, and then ignores it.
    unique_fd pipe_read, pipe_write;
    if (!Pipe(&pipe_read, &pipe_write)) {
        WriteFdExactly(fd.get(), "failed to create pipe\n");
        return;
    }

    fdevent_run_on_main_thread([fd = pipe_read.release()]() {
        fdevent* fde = fdevent_create(
                fd, [](int, unsigned, void*) {}, nullptr);
        fdevent_add(fde, FDE_READ);
    });

    WriteFdExactly(fd.get(), "spinning\n");
}

struct ServiceSocket : public asocket {
    ServiceSocket() {
        install_local_socket(this);
        this->enqueue = [](asocket* self, apacket::payload_type data) {
            return static_cast<ServiceSocket*>(self)->Enqueue(std::move(data));
        };
        this->ready = [](asocket* self) { return static_cast<ServiceSocket*>(self)->Ready(); };
        this->close = [](asocket* self) { return static_cast<ServiceSocket*>(self)->Close(); };
    }
    virtual ~ServiceSocket() = default;

    virtual int Enqueue(apacket::payload_type data) { return -1; }
    virtual void Ready() {}
    virtual void Close() {
        if (peer) {
            peer->peer = nullptr;
            if (peer->shutdown) {
                peer->shutdown(peer);
            }
            peer->close(peer);
        }

        remove_socket(this);
        delete this;
    }
};

struct SinkSocket : public ServiceSocket {
    explicit SinkSocket(size_t byte_count) {
        LOG(INFO) << "Creating new SinkSocket with capacity " << byte_count;
        bytes_left_ = byte_count;
    }

    virtual ~SinkSocket() { LOG(INFO) << "SinkSocket destroyed"; }

    virtual int Enqueue(apacket::payload_type data) override final {
        if (bytes_left_ <= data.size()) {
            // Done reading.
            Close();
            return -1;
        }

        bytes_left_ -= data.size();
        return 0;
    }

    size_t bytes_left_;
};

struct SourceSocket : public ServiceSocket {
    explicit SourceSocket(size_t byte_count) {
        LOG(INFO) << "Creating new SourceSocket with capacity " << byte_count;
        bytes_left_ = byte_count;
    }

    virtual ~SourceSocket() { LOG(INFO) << "SourceSocket destroyed"; }

    void Ready() {
        size_t len = std::min(bytes_left_, get_max_payload());
        if (len == 0) {
            Close();
            return;
        }

        Block block(len);
        memset(block.data(), 0, block.size());
        peer->enqueue(peer, std::move(block));
        bytes_left_ -= len;
    }

    int Enqueue(apacket::payload_type data) { return -1; }

    size_t bytes_left_;
};

asocket* daemon_service_to_socket(std::string_view name) {
    if (name == "jdwp") {
        return create_jdwp_service_socket();
    } else if (name == "track-jdwp") {
        return create_jdwp_tracker_service_socket();
    } else if (android::base::ConsumePrefix(&name, "sink:")) {
        uint64_t byte_count = 0;
        if (!ParseUint(&byte_count, name)) {
            return nullptr;
        }
        return new SinkSocket(byte_count);
    } else if (android::base::ConsumePrefix(&name, "source:")) {
        uint64_t byte_count = 0;
        if (!ParseUint(&byte_count, name)) {
            return nullptr;
        }
        return new SourceSocket(byte_count);
    }

    return nullptr;
}

unique_fd daemon_service_to_fd(std::string_view name, atransport* transport) {
#if defined(__ANDROID__) && !defined(__ANDROID_RECOVERY__)
    if (name.starts_with("abb:") || name.starts_with("abb_exec:")) {
        return execute_abb_command(name);
    }
#endif

#if defined(__ANDROID__)
    if (name.starts_with("framebuffer:")) {
        return create_service_thread("fb", framebuffer_service);
    } else if (android::base::ConsumePrefix(&name, "remount:")) {
        std::string arg(name);
        return create_service_thread("remount",
                                     std::bind(remount_service, std::placeholders::_1, arg));
    } else if (android::base::ConsumePrefix(&name, "reboot:")) {
        std::string arg(name);
        return create_service_thread("reboot",
                                     std::bind(reboot_service, std::placeholders::_1, arg));
    } else if (name.starts_with("root:")) {
        return create_service_thread("root", restart_root_service);
    } else if (name.starts_with("unroot:")) {
        return create_service_thread("unroot", restart_unroot_service);
    } else if (android::base::ConsumePrefix(&name, "backup:")) {
        std::string cmd = "/system/bin/bu backup ";
        cmd += name;
        return StartSubprocess(cmd, nullptr, SubprocessType::kRaw, SubprocessProtocol::kNone);
    } else if (name.starts_with("restore:")) {
        return StartSubprocess("/system/bin/bu restore", nullptr, SubprocessType::kRaw,
                               SubprocessProtocol::kNone);
    } else if (name.starts_with("disable-verity:")) {
        return create_service_thread("verity-on", std::bind(set_verity_enabled_state_service,
                                                            std::placeholders::_1, false));
    } else if (name.starts_with("enable-verity:")) {
        return create_service_thread("verity-off", std::bind(set_verity_enabled_state_service,
                                                             std::placeholders::_1, true));
    } else if (android::base::ConsumePrefix(&name, "tcpip:")) {
        std::string str(name);

        int port;
        if (sscanf(str.c_str(), "%d", &port) != 1) {
            return unique_fd{};
        }
        return create_service_thread("tcp",
                                     std::bind(restart_tcp_service, std::placeholders::_1, port));
    } else if (name.starts_with("usb:")) {
        return create_service_thread("usb", restart_usb_service);
    }
#endif

    if (android::base::ConsumePrefix(&name, "dev:")) {
        return unique_fd{unix_open(name, O_RDWR | O_CLOEXEC)};
    } else if (android::base::ConsumePrefix(&name, "jdwp:")) {
        pid_t pid;
        if (!ParseUint(&pid, name)) {
            return unique_fd{};
        }
        return create_jdwp_connection_fd(pid);
    } else if (android::base::ConsumePrefix(&name, "shell")) {
        return ShellService(name, transport);
    } else if (android::base::ConsumePrefix(&name, "exec:")) {
        return StartSubprocess(std::string(name), nullptr, SubprocessType::kRaw,
                               SubprocessProtocol::kNone);
    } else if (name.starts_with("sync:")) {
        return create_service_thread("sync", file_sync_service);
    } else if (android::base::ConsumePrefix(&name, "reverse:")) {
        return reverse_service(name, transport);
    } else if (name == "reconnect") {
        return create_service_thread(
                "reconnect", std::bind(reconnect_service, std::placeholders::_1, transport));
    } else if (name == "spin") {
        return create_service_thread("spin", spin_service);
    }

    return unique_fd{};
}
