Initial commit: hello-agent — headless RustDesk-protocol-compatible Windows agent

A single-binary, Flutter-free remote-support agent that speaks the stock
RustDesk wire protocol. Designed for one-line MDM deployment against a
self-hosted rustdesk-server: a supporter using the unmodified rustdesk.exe
client connects, the controlled-side user gets a native Win32 approval
prompt, click Yes / No.

CLI surface

    hello-agent.exe --install                # register + start service
    hello-agent.exe --uninstall              # stop, delete, clean up
    hello-agent.exe --config <BLOB>          # admin-UI deploy string
    hello-agent.exe --install --config <BLOB>   # MDM one-liner

--config accepts both forms emitted by the rustdesk-server admin UI: the
reversed-base64 deploy string and the host=,key=,api=,relay= filename
form. Decoded via the upstream custom_server module, persisted via
hbb_common::config::Config::set_option.

Architecture

    --service runs as a Session 0 LocalSystem service. It polls
    WTSGetActiveConsoleSessionId and (re)spawns hello-agent.exe --server
    into the active console session via librustdesk::platform::run_as_user,
    handling the Session 0 → user-session token impersonation.

    --server is the worker. It boots three concurrent components:
      1. cm_popup: an IPC listener on the rustdesk `_cm` named pipe
      2. librustdesk::start_server(true, false): the upstream protocol
         stack — rendezvous mediator, NAT punch, IPC server, screen
         capture, login validation, hbbs_http heartbeat / sysinfo sync
      3. (implicit) ApproveMode::Click is pinned in config, so every
         incoming connection routes through cm_popup

The popup mechanism reuses an existing upstream contract without any
patches to the protocol code: when a peer connects with no password,
Connection::start in the upstream code calls try_start_cm_ipc, which
ipc::connect-s the `_cm` pipe before falling back to spawning a Flutter
CM child. Since cm_popup is up first, step 1 succeeds; we read the
Data::Login{authorized:false} frame, show MessageBoxTimeoutW (Yes/No,
60s, top-most, system-modal), and reply Data::Authorize or Data::Close.

Source tree

    src/main.rs             CLI dispatcher + run_server() composition
    src/cli.rs              hand-rolled argv parser + unit tests
    src/service.rs          windows-service install/uninstall/dispatcher
    src/config_import.rs    --config blob decoding + persistence
    src/cm_popup.rs         _cm IPC listener + Win32 approval dialog

Vendoring

The upstream RustDesk crate is vendored under vendor/rustdesk/ — full
workspace including libs/{hbb_common, scrap, enigo, clipboard,
virtual_display, remote_printer}. This makes the build self-contained
(no submodules, no sibling-repo checkout in CI) and gives us freedom to
fork in a different direction later. Excluded from the vendor: .git,
target/, flutter/, appimage/, flatpak/, fastlane/, docs/, examples/,
ci/, build.py, Dockerfile, upstream README/CLAUDE/AGENTS/GEMINI.

One local divergence vs. upstream: vendor/rustdesk/src/lib.rs flips
`mod custom_server` → `pub mod custom_server` so config_import.rs can
call get_custom_server_from_string without going through the
ui_interface shim. Documented in README.md → "Re-syncing the vendored
copy".

CI

.gitea/workflows/build-windows.yml builds on a self-hosted Windows
runner with Rust 1.75, LLVM 15.0.6 (libclang for bindgen via libvpx-sys),
and a vcpkg cache. The vendored vcpkg.json drives x64-windows-static
deps. The workflow stages the resulting hello-agent.exe into
SignOutput\, reports authenticode signing status (warns on unsigned),
and uploads as artifact. ~15 min full build, faster on incremental.

Out of scope for this commit: Linux/macOS builds, code signing, MSI
packaging, coexistence with stock rustdesk on the same box (currently
shares the RustDesk APP_NAME and config dir).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

vendor/rustdesk/libs/scrap/src/android/ffi.rs

@@ -0,0 +1,511 @@
+use jni::objects::JByteBuffer;
+use jni::objects::JString;
+use jni::objects::JValue;
+use jni::sys::jboolean;
+use jni::JNIEnv;
+use jni::{
+    objects::{GlobalRef, JClass, JObject},
+    strings::JNIString,
+    JavaVM,
+};
+
+use hbb_common::{message_proto::MultiClipboards, protobuf::Message};
+use jni::errors::{Error as JniError, Result as JniResult};
+use lazy_static::lazy_static;
+use serde::Deserialize;
+use std::ops::Not;
+use std::os::raw::c_void;
+use std::sync::atomic::{AtomicPtr, Ordering::SeqCst};
+use std::sync::{Mutex, RwLock};
+use std::time::{Duration, Instant};
+
+lazy_static! {
+    static ref JVM: RwLock<Option<JavaVM>> = RwLock::new(None);
+    static ref MAIN_SERVICE_CTX: RwLock<Option<GlobalRef>> = RwLock::new(None); // MainService -> video service / audio service / info
+    static ref APPLICATION_CONTEXT: RwLock<Option<GlobalRef>> = RwLock::new(None);
+    static ref VIDEO_RAW: Mutex<FrameRaw> = Mutex::new(FrameRaw::new("video", MAX_VIDEO_FRAME_TIMEOUT));
+    static ref AUDIO_RAW: Mutex<FrameRaw> = Mutex::new(FrameRaw::new("audio", MAX_AUDIO_FRAME_TIMEOUT));
+    static ref NDK_CONTEXT_INITED: Mutex<bool> = Default::default();
+    static ref MEDIA_CODEC_INFOS: RwLock<Option<MediaCodecInfos>> = RwLock::new(None);
+    static ref CLIPBOARD_MANAGER: RwLock<Option<GlobalRef>> = RwLock::new(None);
+    static ref CLIPBOARDS_HOST: Mutex<Option<MultiClipboards>> = Mutex::new(None);
+    static ref CLIPBOARDS_CLIENT: Mutex<Option<MultiClipboards>> = Mutex::new(None);
+}
+
+const MAX_VIDEO_FRAME_TIMEOUT: Duration = Duration::from_millis(100);
+const MAX_AUDIO_FRAME_TIMEOUT: Duration = Duration::from_millis(1000);
+
+struct FrameRaw {
+    name: &'static str,
+    ptr: AtomicPtr<u8>,
+    len: usize,
+    last_update: Instant,
+    timeout: Duration,
+    enable: bool,
+}
+
+impl FrameRaw {
+    fn new(name: &'static str, timeout: Duration) -> Self {
+        FrameRaw {
+            name,
+            ptr: AtomicPtr::default(),
+            len: 0,
+            last_update: Instant::now(),
+            timeout,
+            enable: false,
+        }
+    }
+
+    fn set_enable(&mut self, value: bool) {
+        self.enable = value;
+        self.ptr.store(std::ptr::null_mut(), SeqCst);
+        self.len = 0;
+    }
+
+    fn update(&mut self, data: *mut u8, len: usize) {
+        if self.enable.not() {
+            return;
+        }
+        self.len = len;
+        self.ptr.store(data, SeqCst);
+        self.last_update = Instant::now();
+    }
+
+    // take inner data as slice
+    // release when success
+    fn take<'a>(&mut self, dst: &mut Vec<u8>, last: &mut Vec<u8>) -> Option<()> {
+        if self.enable.not() {
+            return None;
+        }
+        let ptr = self.ptr.load(SeqCst);
+        if ptr.is_null() || self.len == 0 {
+            None
+        } else {
+            if self.last_update.elapsed() > self.timeout {
+                log::trace!("Failed to take {} raw,timeout!", self.name);
+                return None;
+            }
+            let slice = unsafe { std::slice::from_raw_parts(ptr, self.len) };
+            self.release();
+            if last.len() == slice.len() && crate::would_block_if_equal(last, slice).is_err() {
+                return None;
+            }
+            dst.resize(slice.len(), 0);
+            unsafe {
+                std::ptr::copy_nonoverlapping(slice.as_ptr(), dst.as_mut_ptr(), slice.len());
+            }
+            Some(())
+        }
+    }
+
+    fn release(&mut self) {
+        self.len = 0;
+        self.ptr.store(std::ptr::null_mut(), SeqCst);
+    }
+}
+
+pub fn get_video_raw<'a>(dst: &mut Vec<u8>, last: &mut Vec<u8>) -> Option<()> {
+    VIDEO_RAW.lock().ok()?.take(dst, last)
+}
+
+pub fn get_audio_raw<'a>(dst: &mut Vec<u8>, last: &mut Vec<u8>) -> Option<()> {
+    AUDIO_RAW.lock().ok()?.take(dst, last)
+}
+
+pub fn get_clipboards(client: bool) -> Option<MultiClipboards> {
+    if client {
+        CLIPBOARDS_CLIENT.lock().ok()?.take()
+    } else {
+        CLIPBOARDS_HOST.lock().ok()?.take()
+    }
+}
+
+#[no_mangle]
+pub extern "system" fn Java_ffi_FFI_onVideoFrameUpdate(
+    env: JNIEnv,
+    _class: JClass,
+    buffer: JObject,
+) {
+    let jb = JByteBuffer::from(buffer);
+    if let Ok(data) = env.get_direct_buffer_address(&jb) {
+        if let Ok(len) = env.get_direct_buffer_capacity(&jb) {
+            VIDEO_RAW.lock().unwrap().update(data, len);
+        }
+    }
+}
+
+#[no_mangle]
+pub extern "system" fn Java_ffi_FFI_onAudioFrameUpdate(
+    env: JNIEnv,
+    _class: JClass,
+    buffer: JObject,
+) {
+    let jb = JByteBuffer::from(buffer);
+    if let Ok(data) = env.get_direct_buffer_address(&jb) {
+        if let Ok(len) = env.get_direct_buffer_capacity(&jb) {
+            AUDIO_RAW.lock().unwrap().update(data, len);
+        }
+    }
+}
+
+#[no_mangle]
+pub extern "system" fn Java_ffi_FFI_onClipboardUpdate(
+    env: JNIEnv,
+    _class: JClass,
+    buffer: JByteBuffer,
+) {
+    if let Ok(data) = env.get_direct_buffer_address(&buffer) {
+        if let Ok(len) = env.get_direct_buffer_capacity(&buffer) {
+            let data = unsafe { std::slice::from_raw_parts(data, len) };
+            if let Ok(clips) = MultiClipboards::parse_from_bytes(&data[1..]) {
+                let is_client = data[0] == 1;
+                if is_client {
+                    *CLIPBOARDS_CLIENT.lock().unwrap() = Some(clips);
+                } else {
+                    *CLIPBOARDS_HOST.lock().unwrap() = Some(clips);
+                }
+            }
+        }
+    }
+}
+
+#[no_mangle]
+pub extern "system" fn Java_ffi_FFI_setFrameRawEnable(
+    env: JNIEnv,
+    _class: JClass,
+    name: JString,
+    value: jboolean,
+) {
+    let mut env = env;
+    if let Ok(name) = env.get_string(&name) {
+        let name: String = name.into();
+        let value = value.eq(&1);
+        if name.eq("video") {
+            VIDEO_RAW.lock().unwrap().set_enable(value);
+        } else if name.eq("audio") {
+            AUDIO_RAW.lock().unwrap().set_enable(value);
+        }
+    };
+}
+
+#[no_mangle]
+pub extern "system" fn Java_ffi_FFI_init(env: JNIEnv, _class: JClass, ctx: JObject) {
+    log::debug!("MainService init from java");
+    if let Ok(jvm) = env.get_java_vm() {
+        let java_vm = jvm.get_java_vm_pointer() as *mut c_void;
+        let mut jvm_lock = JVM.write().unwrap();
+        if jvm_lock.is_none() {
+            *jvm_lock = Some(jvm);
+        }
+        drop(jvm_lock);
+        if let Ok(context) = env.new_global_ref(ctx) {
+            let context_jobject = context.as_obj().as_raw() as *mut c_void;
+            *MAIN_SERVICE_CTX.write().unwrap() = Some(context);
+            init_ndk_context(java_vm, context_jobject);
+        }
+    }
+}
+
+#[no_mangle]
+pub extern "system" fn Java_ffi_FFI_setClipboardManager(
+    env: JNIEnv,
+    _class: JClass,
+    clipboard_manager: JObject,
+) {
+    log::debug!("ClipboardManager init from java");
+    if let Ok(jvm) = env.get_java_vm() {
+        let java_vm = jvm.get_java_vm_pointer() as *mut c_void;
+        let mut jvm_lock = JVM.write().unwrap();
+        if jvm_lock.is_none() {
+            *jvm_lock = Some(jvm);
+        }
+        drop(jvm_lock);
+        if let Ok(manager) = env.new_global_ref(clipboard_manager) {
+            *CLIPBOARD_MANAGER.write().unwrap() = Some(manager);
+        }
+    }
+}
+
+#[derive(Debug, Deserialize, Clone)]
+pub struct MediaCodecInfo {
+    pub name: String,
+    pub is_encoder: bool,
+    #[serde(default)]
+    pub hw: Option<bool>, // api 29+
+    pub mime_type: String,
+    pub surface: bool,
+    pub nv12: bool,
+    #[serde(default)]
+    pub low_latency: Option<bool>, // api 30+, decoder
+    pub min_bitrate: u32,
+    pub max_bitrate: u32,
+    pub min_width: usize,
+    pub max_width: usize,
+    pub min_height: usize,
+    pub max_height: usize,
+}
+
+#[derive(Debug, Deserialize, Clone)]
+pub struct MediaCodecInfos {
+    pub version: usize,
+    pub w: usize, // aligned
+    pub h: usize, // aligned
+    pub codecs: Vec<MediaCodecInfo>,
+}
+
+#[no_mangle]
+pub extern "system" fn Java_ffi_FFI_setCodecInfo(env: JNIEnv, _class: JClass, info: JString) {
+    let mut env = env;
+    if let Ok(info) = env.get_string(&info) {
+        let info: String = info.into();
+        if let Ok(infos) = serde_json::from_str::<MediaCodecInfos>(&info) {
+            *MEDIA_CODEC_INFOS.write().unwrap() = Some(infos);
+        }
+    }
+}
+
+pub fn get_codec_info() -> Option<MediaCodecInfos> {
+    MEDIA_CODEC_INFOS.read().unwrap().as_ref().cloned()
+}
+
+pub fn clear_codec_info() {
+    *MEDIA_CODEC_INFOS.write().unwrap() = None;
+}
+
+// another way to fix "reference table overflow" error caused by new_string and call_main_service_pointer_input frequently calld
+// is below, but here I change kind from string to int for performance
+/*
+        env.with_local_frame(10, || {
+            let kind = env.new_string(kind)?;
+            env.call_method(
+                ctx,
+                "rustPointerInput",
+                "(Ljava/lang/String;III)V",
+                &[
+                    JValue::Object(&JObject::from(kind)),
+                    JValue::Int(mask),
+                    JValue::Int(x),
+                    JValue::Int(y),
+                ],
+            )?;
+            Ok(JObject::null())
+        })?;
+*/
+pub fn call_main_service_pointer_input(kind: &str, mask: i32, x: i32, y: i32) -> JniResult<()> {
+    if let (Some(jvm), Some(ctx)) = (
+        JVM.read().unwrap().as_ref(),
+        MAIN_SERVICE_CTX.read().unwrap().as_ref(),
+    ) {
+        let mut env = jvm.attach_current_thread_as_daemon()?;
+        let kind = if kind == "touch" { 0 } else { 1 };
+        env.call_method(
+            ctx,
+            "rustPointerInput",
+            "(IIII)V",
+            &[
+                JValue::Int(kind),
+                JValue::Int(mask),
+                JValue::Int(x),
+                JValue::Int(y),
+            ],
+        )?;
+        return Ok(());
+    } else {
+        return Err(JniError::ThrowFailed(-1));
+    }
+}
+
+pub fn call_main_service_key_event(data: &[u8]) -> JniResult<()> {
+    if let (Some(jvm), Some(ctx)) = (
+        JVM.read().unwrap().as_ref(),
+        MAIN_SERVICE_CTX.read().unwrap().as_ref(),
+    ) {
+        let mut env = jvm.attach_current_thread_as_daemon()?;
+        let data = env.byte_array_from_slice(data)?;
+
+        env.call_method(
+            ctx,
+            "rustKeyEventInput",
+            "([B)V",
+            &[JValue::Object(&JObject::from(data))],
+        )?;
+        return Ok(());
+    } else {
+        return Err(JniError::ThrowFailed(-1));
+    }
+}
+
+fn _call_clipboard_manager<S, T>(name: S, sig: T, args: &[JValue]) -> JniResult<()>
+where
+    S: Into<JNIString>,
+    T: Into<JNIString> + AsRef<str>,
+{
+    if let (Some(jvm), Some(cm)) = (
+        JVM.read().unwrap().as_ref(),
+        CLIPBOARD_MANAGER.read().unwrap().as_ref(),
+    ) {
+        let mut env = jvm.attach_current_thread()?;
+        env.call_method(cm, name, sig, args)?;
+        return Ok(());
+    } else {
+        return Err(JniError::ThrowFailed(-1));
+    }
+}
+
+pub fn call_clipboard_manager_update_clipboard(data: &[u8]) -> JniResult<()> {
+    if let (Some(jvm), Some(cm)) = (
+        JVM.read().unwrap().as_ref(),
+        CLIPBOARD_MANAGER.read().unwrap().as_ref(),
+    ) {
+        let mut env = jvm.attach_current_thread()?;
+        let data = env.byte_array_from_slice(data)?;
+
+        env.call_method(
+            cm,
+            "rustUpdateClipboard",
+            "([B)V",
+            &[JValue::Object(&JObject::from(data))],
+        )?;
+        return Ok(());
+    } else {
+        return Err(JniError::ThrowFailed(-1));
+    }
+}
+
+pub fn call_clipboard_manager_enable_client_clipboard(enable: bool) -> JniResult<()> {
+    _call_clipboard_manager(
+        "rustEnableClientClipboard",
+        "(Z)V",
+        &[JValue::Bool(jboolean::from(enable))],
+    )
+}
+
+pub fn call_main_service_get_by_name(name: &str) -> JniResult<String> {
+    if let (Some(jvm), Some(ctx)) = (
+        JVM.read().unwrap().as_ref(),
+        MAIN_SERVICE_CTX.read().unwrap().as_ref(),
+    ) {
+        let mut env = jvm.attach_current_thread_as_daemon()?;
+        let res = env.with_local_frame(10, |env| -> JniResult<String> {
+            let name = env.new_string(name)?;
+            let res = env
+                .call_method(
+                    ctx,
+                    "rustGetByName",
+                    "(Ljava/lang/String;)Ljava/lang/String;",
+                    &[JValue::Object(&JObject::from(name))],
+                )?
+                .l()?;
+            let res = JString::from(res);
+            let res = env.get_string(&res)?;
+            let res = res.to_string_lossy().to_string();
+            Ok(res)
+        })?;
+        Ok(res)
+    } else {
+        return Err(JniError::ThrowFailed(-1));
+    }
+}
+
+pub fn call_main_service_set_by_name(
+    name: &str,
+    arg1: Option<&str>,
+    arg2: Option<&str>,
+) -> JniResult<()> {
+    if let (Some(jvm), Some(ctx)) = (
+        JVM.read().unwrap().as_ref(),
+        MAIN_SERVICE_CTX.read().unwrap().as_ref(),
+    ) {
+        let mut env = jvm.attach_current_thread_as_daemon()?;
+        env.with_local_frame(10, |env| -> JniResult<()> {
+            let name = env.new_string(name)?;
+            let arg1 = env.new_string(arg1.unwrap_or(""))?;
+            let arg2 = env.new_string(arg2.unwrap_or(""))?;
+
+            env.call_method(
+                ctx,
+                "rustSetByName",
+                "(Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;)V",
+                &[
+                    JValue::Object(&JObject::from(name)),
+                    JValue::Object(&JObject::from(arg1)),
+                    JValue::Object(&JObject::from(arg2)),
+                ],
+            )?;
+            Ok(())
+        })?;
+        return Ok(());
+    } else {
+        return Err(JniError::ThrowFailed(-1));
+    }
+}
+
+// Difference between MainService, MainActivity, JNI_OnLoad:
+//  jvm is the same, ctx is differen and ctx of JNI_OnLoad is null.
+//  cpal: all three works
+//  Service(GetByName, ...): only ctx from MainService works, so use 2 init context functions
+// On app start: JNI_OnLoad or MainActivity init context
+// On service start first time: MainService replace the context
+
+fn init_ndk_context(java_vm: *mut c_void, context_jobject: *mut c_void) {
+    let mut lock = NDK_CONTEXT_INITED.lock().unwrap();
+    if *lock {
+        unsafe {
+            ndk_context::release_android_context();
+        }
+        *lock = false;
+    }
+    unsafe {
+        ndk_context::initialize_android_context(java_vm, context_jobject);
+        #[cfg(feature = "hwcodec")]
+        hwcodec::android::ffmpeg_set_java_vm(java_vm);
+    }
+    *lock = true;
+}
+
+fn try_init_rustls_platform_verifier(env: &mut JNIEnv, context_jobject: *mut c_void) {
+    use hbb_common::config::ANDROID_RUSTLS_PLATFORM_VERIFIER_INITIALIZED as INITIALIZED;
+    use std::sync::atomic::Ordering;
+    let initialized = INITIALIZED.load(Ordering::Relaxed);
+    if !initialized {
+        let ctx_for_rustls = unsafe { JObject::from_raw(context_jobject as jni::sys::jobject) };
+        if let Err(e) =
+            hbb_common::rustls_platform_verifier::android::init_hosted(env, ctx_for_rustls)
+        {
+            log::error!("Failed to initialize rustls-platform-verifier: {:?}", e);
+        } else {
+            INITIALIZED.store(true, Ordering::Relaxed);
+            log::info!("rustls-platform-verifier initialized successfully");
+        }
+    }
+}
+
+// https://cjycode.com/flutter_rust_bridge/guides/how-to/ndk-init
+#[no_mangle]
+pub extern "C" fn JNI_OnLoad(vm: jni::JavaVM, res: *mut std::os::raw::c_void) -> jni::sys::jint {
+    if let Ok(env) = vm.get_env() {
+        let vm = vm.get_java_vm_pointer() as *mut std::os::raw::c_void;
+        init_ndk_context(vm, res);
+    }
+    jni::JNIVersion::V6.into()
+}
+
+#[no_mangle]
+pub extern "system" fn Java_ffi_FFI_onAppStart(mut env: JNIEnv, _class: JClass, ctx: JObject) {
+    if ctx.is_null() {
+        log::error!("application context is null");
+        return;
+    }
+    if APPLICATION_CONTEXT.read().unwrap().is_some() {
+        log::info!("application context already initialized");
+        return;
+    }
+    if let Ok(jvm) = env.get_java_vm() {
+        if let Ok(context) = env.new_global_ref(ctx) {
+            let java_vm = jvm.get_java_vm_pointer() as *mut c_void;
+            let context_jobject = context.as_obj().as_raw() as *mut c_void;
+            *APPLICATION_CONTEXT.write().unwrap() = Some(context);
+            try_init_rustls_platform_verifier(&mut env, context_jobject);
+        }
+    }
+}

vendor/rustdesk/libs/scrap/src/android/mod.rs

@@ -0,0 +1,3 @@
+pub mod ffi;
+
+pub use ffi::*;