server: add UVC control helper

This commit is contained in:
Brad Stein 2026-01-06 04:38:41 -03:00
parent 27a69a8bb6
commit 30eab21166
3 changed files with 618 additions and 5 deletions

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@ -131,10 +131,11 @@ else
fi
echo "==> 4b. Source build"
sudo -u "$ORIG_USER" bash -c "cd '$SRC_DIR/server' && cargo clean && cargo build --release"
sudo -u "$ORIG_USER" bash -c "cd '$SRC_DIR/server' && cargo clean && cargo build --release --bins"
echo "==> 5. Install binaries"
sudo install -Dm755 "$SRC_DIR/server/target/release/lesavka-server" /usr/local/bin/lesavka-server
sudo install -Dm755 "$SRC_DIR/server/target/release/lesavka-uvc" /usr/local/bin/lesavka-uvc
sudo install -Dm755 "$SRC_DIR/scripts/daemon/lesavka-core.sh" /usr/local/bin/lesavka-core.sh
echo "==> 6a. Systemd units - lesavka-core"

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@ -0,0 +1,527 @@
// lesavka-uvc - minimal UVC control handler for the gadget node.
use anyhow::{Context, Result};
use std::env;
use std::fs::OpenOptions;
use std::os::unix::fs::OpenOptionsExt;
use std::os::unix::io::AsRawFd;
use std::thread;
use std::time::Duration;
const STREAM_CTRL_SIZE: usize = 34;
const UVC_DATA_SIZE: usize = 60;
const V4L2_EVENT_PRIVATE_START: u32 = 0x0800_0000;
const UVC_EVENT_CONNECT: u32 = V4L2_EVENT_PRIVATE_START + 0;
const UVC_EVENT_DISCONNECT: u32 = V4L2_EVENT_PRIVATE_START + 1;
const UVC_EVENT_STREAMON: u32 = V4L2_EVENT_PRIVATE_START + 2;
const UVC_EVENT_STREAMOFF: u32 = V4L2_EVENT_PRIVATE_START + 3;
const UVC_EVENT_SETUP: u32 = V4L2_EVENT_PRIVATE_START + 4;
const UVC_EVENT_DATA: u32 = V4L2_EVENT_PRIVATE_START + 5;
const UVC_STRING_CONTROL_IDX: u8 = 0;
const UVC_STRING_STREAMING_IDX: u8 = 1;
const USB_DIR_IN: u8 = 0x80;
const UVC_SET_CUR: u8 = 0x01;
const UVC_GET_CUR: u8 = 0x81;
const UVC_GET_MIN: u8 = 0x82;
const UVC_GET_MAX: u8 = 0x83;
const UVC_GET_RES: u8 = 0x84;
const UVC_GET_LEN: u8 = 0x85;
const UVC_GET_INFO: u8 = 0x86;
const UVC_GET_DEF: u8 = 0x87;
const UVC_VS_PROBE_CONTROL: u8 = 0x01;
const UVC_VS_COMMIT_CONTROL: u8 = 0x02;
const UVC_VC_REQUEST_ERROR_CODE_CONTROL: u8 = 0x02;
#[repr(C)]
struct V4l2EventSubscription {
type_: u32,
id: u32,
flags: u32,
reserved: [u32; 5],
}
#[repr(C)]
union V4l2EventUnion {
data: [u8; 64],
_align: u64,
}
#[repr(C)]
struct V4l2Event {
type_: u32,
u: V4l2EventUnion,
pending: u32,
sequence: u32,
timestamp: libc::timespec,
id: u32,
reserved: [u32; 8],
}
#[repr(C)]
#[derive(Clone, Copy)]
struct UsbCtrlRequest {
b_request_type: u8,
b_request: u8,
w_value: u16,
w_index: u16,
w_length: u16,
}
#[repr(C)]
#[derive(Clone, Copy)]
struct UvcRequestData {
length: i32,
data: [u8; UVC_DATA_SIZE],
}
#[derive(Clone, Copy)]
struct UvcConfig {
width: u32,
height: u32,
fps: u32,
interval: u32,
max_packet: u32,
}
struct UvcState {
cfg: UvcConfig,
default: [u8; STREAM_CTRL_SIZE],
probe: [u8; STREAM_CTRL_SIZE],
commit: [u8; STREAM_CTRL_SIZE],
}
#[derive(Clone, Copy)]
struct PendingRequest {
interface: u8,
selector: u8,
}
fn main() -> Result<()> {
let (dev, cfg) = parse_args()?;
eprintln!("[lesavka-uvc] starting (dev={dev})");
loop {
let file = open_with_retry(&dev)?;
let fd = file.as_raw_fd();
let vidioc_subscribe = ioctl_write::<V4l2EventSubscription>(b'V', 90);
let vidioc_dqevent = ioctl_read::<V4l2Event>(b'V', 89);
let uvc_send_response = ioctl_write::<UvcRequestData>(b'U', 1);
subscribe_event(fd, vidioc_subscribe, UVC_EVENT_SETUP)?;
subscribe_event(fd, vidioc_subscribe, UVC_EVENT_DATA)?;
let _ = subscribe_event(fd, vidioc_subscribe, UVC_EVENT_CONNECT);
let _ = subscribe_event(fd, vidioc_subscribe, UVC_EVENT_DISCONNECT);
let _ = subscribe_event(fd, vidioc_subscribe, UVC_EVENT_STREAMON);
let _ = subscribe_event(fd, vidioc_subscribe, UVC_EVENT_STREAMOFF);
let mut state = UvcState::new(cfg);
let mut pending: Option<PendingRequest> = None;
loop {
let mut ev = unsafe { std::mem::zeroed::<V4l2Event>() };
let rc = unsafe { libc::ioctl(fd, vidioc_dqevent, &mut ev) };
if rc < 0 {
let err = std::io::Error::last_os_error();
match err.raw_os_error() {
Some(libc::EAGAIN) | Some(libc::EINTR) => {
thread::sleep(Duration::from_millis(10));
continue;
}
Some(libc::ENODEV) | Some(libc::EBADF) | Some(libc::EIO) => {
eprintln!("[lesavka-uvc] device reset ({err}); reopening");
break;
}
_ => {
eprintln!("[lesavka-uvc] dqevent failed: {err}");
thread::sleep(Duration::from_millis(100));
continue;
}
}
}
match ev.type_ {
UVC_EVENT_CONNECT => {
let speed = u32::from_le_bytes(event_bytes(&ev)[0..4].try_into().unwrap());
eprintln!("[lesavka-uvc] UVC connect (speed={speed})");
}
UVC_EVENT_DISCONNECT => eprintln!("[lesavka-uvc] UVC disconnect"),
UVC_EVENT_STREAMON => eprintln!("[lesavka-uvc] stream on"),
UVC_EVENT_STREAMOFF => eprintln!("[lesavka-uvc] stream off"),
UVC_EVENT_SETUP => {
let req = parse_ctrl_request(event_bytes(&ev));
handle_setup(
fd,
uvc_send_response,
&mut state,
&mut pending,
req,
);
}
UVC_EVENT_DATA => {
let data = parse_request_data(event_bytes(&ev));
handle_data(fd, uvc_send_response, &mut state, &mut pending, data);
}
_ => {}
}
}
}
}
fn parse_args() -> Result<(String, UvcConfig)> {
let mut args = env::args().skip(1);
let mut dev: Option<String> = None;
while let Some(arg) = args.next() {
match arg.as_str() {
"--device" | "-d" => dev = args.next(),
_ => dev = Some(arg),
}
}
let dev = dev
.or_else(|| env::var("LESAVKA_UVC_DEV").ok())
.context("missing --device (or LESAVKA_UVC_DEV)")?;
Ok((dev, UvcConfig::from_env()))
}
impl UvcConfig {
fn from_env() -> Self {
let width = env_u32("LESAVKA_UVC_WIDTH", 640);
let height = env_u32("LESAVKA_UVC_HEIGHT", 480);
let fps = env_u32("LESAVKA_UVC_FPS", 30).max(1);
let interval = env_u32("LESAVKA_UVC_INTERVAL", 0);
let mut max_packet = env_u32("LESAVKA_UVC_MAXPACKET", 3072);
if env::var("LESAVKA_UVC_BULK").is_ok() {
max_packet = max_packet.min(1024);
}
let interval = if interval == 0 {
10_000_000 / fps
} else {
interval
};
Self {
width,
height,
fps,
interval,
max_packet,
}
}
}
impl UvcState {
fn new(cfg: UvcConfig) -> Self {
let default = build_streaming_control(&cfg);
Self {
cfg,
default,
probe: default,
commit: default,
}
}
}
fn open_with_retry(path: &str) -> Result<std::fs::File> {
for attempt in 1..=200 {
match OpenOptions::new()
.read(true)
.write(true)
.custom_flags(libc::O_NONBLOCK)
.open(path)
{
Ok(f) => {
eprintln!("[lesavka-uvc] opened {path} (attempt {attempt})");
return Ok(f);
}
Err(err) if err.raw_os_error() == Some(libc::ENOENT) => {
thread::sleep(Duration::from_millis(50));
}
Err(err) => return Err(err).with_context(|| format!("open {path}")),
}
}
Err(anyhow::anyhow!("timeout opening {path}"))
}
fn subscribe_event(fd: i32, req: libc::c_ulong, event: u32) -> Result<()> {
let mut sub = V4l2EventSubscription {
type_: event,
id: 0,
flags: 0,
reserved: [0; 5],
};
let rc = unsafe { libc::ioctl(fd, req, &mut sub) };
if rc < 0 {
return Err(std::io::Error::last_os_error()).with_context(|| {
format!("subscribe event {event:#x} (fd={fd})")
});
}
Ok(())
}
fn handle_setup(
fd: i32,
uvc_send_response: libc::c_ulong,
state: &mut UvcState,
pending: &mut Option<PendingRequest>,
req: UsbCtrlRequest,
) {
let interface = (req.w_index & 0xff) as u8;
let selector = (req.w_value >> 8) as u8;
let is_in = (req.b_request_type & USB_DIR_IN) != 0;
if !is_in && req.b_request == UVC_SET_CUR {
*pending = Some(PendingRequest { interface, selector });
return;
}
if !is_in {
let _ = send_stall(fd, uvc_send_response);
return;
}
let payload = build_in_response(state, interface, selector, req.b_request);
match payload {
Some(bytes) => {
let _ = send_response(fd, uvc_send_response, &bytes);
}
None => {
let _ = send_stall(fd, uvc_send_response);
}
}
}
fn handle_data(
fd: i32,
uvc_send_response: libc::c_ulong,
state: &mut UvcState,
pending: &mut Option<PendingRequest>,
data: UvcRequestData,
) {
let Some(p) = pending.take() else {
let _ = send_response(fd, uvc_send_response, &[]);
return;
};
if data.length < 0 {
let _ = send_stall(fd, uvc_send_response);
return;
}
let len = data.length as usize;
let slice = &data.data[..len.min(data.data.len())];
if p.interface == UVC_STRING_STREAMING_IDX
&& matches!(p.selector, UVC_VS_PROBE_CONTROL | UVC_VS_COMMIT_CONTROL)
{
let sanitized = sanitize_streaming_control(slice, state);
if p.selector == UVC_VS_PROBE_CONTROL {
state.probe = sanitized;
} else {
state.commit = sanitized;
}
}
let _ = send_response(fd, uvc_send_response, &[]);
}
fn build_in_response(
state: &UvcState,
interface: u8,
selector: u8,
request: u8,
) -> Option<Vec<u8>> {
match interface {
UVC_STRING_STREAMING_IDX => build_streaming_response(state, selector, request),
UVC_STRING_CONTROL_IDX => build_control_response(selector, request),
_ => None,
}
}
fn build_streaming_response(
state: &UvcState,
selector: u8,
request: u8,
) -> Option<Vec<u8>> {
let current = match selector {
UVC_VS_PROBE_CONTROL => state.probe,
UVC_VS_COMMIT_CONTROL => state.commit,
_ => return None,
};
match request {
UVC_GET_INFO => Some(vec![0x03]),
UVC_GET_LEN => Some((STREAM_CTRL_SIZE as u16).to_le_bytes().to_vec()),
UVC_GET_CUR => Some(current.to_vec()),
UVC_GET_MIN | UVC_GET_MAX | UVC_GET_DEF | UVC_GET_RES => Some(state.default.to_vec()),
_ => None,
}
}
fn build_control_response(selector: u8, request: u8) -> Option<Vec<u8>> {
match request {
UVC_GET_INFO => Some(vec![0x01]),
UVC_GET_LEN => Some(1u16.to_le_bytes().to_vec()),
UVC_GET_CUR | UVC_GET_MIN | UVC_GET_MAX | UVC_GET_DEF | UVC_GET_RES => {
if selector == UVC_VC_REQUEST_ERROR_CODE_CONTROL {
Some(vec![0x00])
} else {
Some(vec![0x00])
}
}
_ => None,
}
}
fn sanitize_streaming_control(data: &[u8], state: &UvcState) -> [u8; STREAM_CTRL_SIZE] {
let mut out = state.default;
if data.len() >= STREAM_CTRL_SIZE {
let format_index = data[2];
let frame_index = data[3];
let interval = read_le32(data, 4);
if format_index == 1 {
out[2] = 1;
}
if frame_index == 1 {
out[3] = 1;
}
if interval == state.cfg.interval {
write_le32(&mut out[4..8], interval);
}
}
out
}
fn send_response(fd: i32, req: libc::c_ulong, payload: &[u8]) -> Result<()> {
let mut resp = UvcRequestData {
length: payload.len() as i32,
data: [0u8; UVC_DATA_SIZE],
};
let n = payload.len().min(UVC_DATA_SIZE);
resp.data[..n].copy_from_slice(&payload[..n]);
let rc = unsafe { libc::ioctl(fd, req, &resp) };
if rc < 0 {
return Err(std::io::Error::last_os_error()).context("UVCIOC_SEND_RESPONSE");
}
Ok(())
}
fn send_stall(fd: i32, req: libc::c_ulong) -> Result<()> {
let resp = UvcRequestData {
length: -1,
data: [0u8; UVC_DATA_SIZE],
};
let rc = unsafe { libc::ioctl(fd, req, &resp) };
if rc < 0 {
return Err(std::io::Error::last_os_error()).context("UVCIOC_SEND_RESPONSE(stall)");
}
Ok(())
}
fn build_streaming_control(cfg: &UvcConfig) -> [u8; STREAM_CTRL_SIZE] {
let mut buf = [0u8; STREAM_CTRL_SIZE];
let frame_size = cfg.width * cfg.height * 2;
write_le16(&mut buf[0..2], 1); // bmHint: dwFrameInterval
buf[2] = 1; // bFormatIndex
buf[3] = 1; // bFrameIndex
write_le32(&mut buf[4..8], cfg.interval);
write_le16(&mut buf[8..10], 0);
write_le16(&mut buf[10..12], 0);
write_le16(&mut buf[12..14], 0);
write_le16(&mut buf[14..16], 0);
write_le16(&mut buf[16..18], 0);
write_le32(&mut buf[18..22], frame_size);
write_le32(&mut buf[22..26], cfg.max_packet);
write_le32(&mut buf[26..30], 48_000_000);
buf[30] = 0;
buf[31] = 0;
buf[32] = 0;
buf[33] = 0;
buf
}
fn event_bytes(ev: &V4l2Event) -> [u8; 64] {
unsafe { ev.u.data }
}
fn parse_ctrl_request(data: [u8; 64]) -> UsbCtrlRequest {
UsbCtrlRequest {
b_request_type: data[0],
b_request: data[1],
w_value: u16::from_le_bytes([data[2], data[3]]),
w_index: u16::from_le_bytes([data[4], data[5]]),
w_length: u16::from_le_bytes([data[6], data[7]]),
}
}
fn parse_request_data(data: [u8; 64]) -> UvcRequestData {
let length = i32::from_le_bytes([data[0], data[1], data[2], data[3]]);
let mut out = [0u8; UVC_DATA_SIZE];
out.copy_from_slice(&data[4..64]);
UvcRequestData { length, data: out }
}
fn env_u32(name: &str, default: u32) -> u32 {
env::var(name)
.ok()
.and_then(|v| v.parse::<u32>().ok())
.unwrap_or(default)
}
fn write_le16(dst: &mut [u8], val: u16) {
let bytes = val.to_le_bytes();
dst[0] = bytes[0];
dst[1] = bytes[1];
}
fn write_le32(dst: &mut [u8], val: u32) {
let bytes = val.to_le_bytes();
dst[0] = bytes[0];
dst[1] = bytes[1];
dst[2] = bytes[2];
dst[3] = bytes[3];
}
fn read_le32(src: &[u8], offset: usize) -> u32 {
u32::from_le_bytes([src[offset], src[offset + 1], src[offset + 2], src[offset + 3]])
}
const IOC_NRBITS: u8 = 8;
const IOC_TYPEBITS: u8 = 8;
const IOC_SIZEBITS: u8 = 14;
const IOC_DIRBITS: u8 = 2;
const IOC_NRSHIFT: u8 = 0;
const IOC_TYPESHIFT: u8 = IOC_NRSHIFT + IOC_NRBITS;
const IOC_SIZESHIFT: u8 = IOC_TYPESHIFT + IOC_TYPEBITS;
const IOC_DIRSHIFT: u8 = IOC_SIZESHIFT + IOC_SIZEBITS;
const IOC_READ: u8 = 2;
const IOC_WRITE: u8 = 1;
fn ioctl_read<T>(type_: u8, nr: u8) -> libc::c_ulong {
ioc(IOC_READ, type_, nr, std::mem::size_of::<T>() as u16)
}
fn ioctl_write<T>(type_: u8, nr: u8) -> libc::c_ulong {
ioc(IOC_WRITE, type_, nr, std::mem::size_of::<T>() as u16)
}
fn ioc(dir: u8, type_: u8, nr: u8, size: u16) -> libc::c_ulong {
let dir = (dir as u32) << IOC_DIRSHIFT;
let ty = (type_ as u32) << IOC_TYPESHIFT;
let nr = (nr as u32) << IOC_NRSHIFT;
let size = (size as u32) << IOC_SIZESHIFT;
(dir | ty | nr | size) as libc::c_ulong
}

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@ -5,9 +5,9 @@
use anyhow::Context as _;
use futures_util::{Stream, StreamExt};
use gstreamer as gst;
use std::sync::atomic::AtomicBool;
use std::sync::atomic::{AtomicBool, Ordering};
use std::time::{Duration, SystemTime, UNIX_EPOCH};
use std::{backtrace::Backtrace, panic, pin::Pin, sync::Arc};
use std::{backtrace::Backtrace, panic, pin::Pin, process::Command, sync::Arc};
use tokio::{fs::OpenOptions, io::AsyncWriteExt, sync::Mutex};
use tokio_stream::wrappers::ReceiverStream;
use tonic::transport::Server;
@ -89,6 +89,50 @@ fn next_minute() -> SystemTime {
UNIX_EPOCH + Duration::from_secs(next)
}
async fn recover_hid_if_needed(
err: &std::io::Error,
gadget: UsbGadget,
kb: Arc<Mutex<tokio::fs::File>>,
ms: Arc<Mutex<tokio::fs::File>>,
did_cycle: Arc<AtomicBool>,
) {
let code = err.raw_os_error();
let should_recover = matches!(code, Some(libc::ENOTCONN) | Some(libc::ESHUTDOWN) | Some(libc::EPIPE));
if !should_recover {
return;
}
if did_cycle
.compare_exchange(false, true, Ordering::SeqCst, Ordering::SeqCst)
.is_err()
{
return;
}
tokio::spawn(async move {
warn!("🔁 HID transport down (errno={code:?}) - cycling gadget");
match tokio::task::spawn_blocking(move || gadget.cycle()).await {
Ok(Ok(())) => info!("✅ USB gadget cycle complete (auto-recover)"),
Ok(Err(e)) => error!("💥 USB gadget cycle failed: {e:#}"),
Err(e) => error!("💥 USB gadget cycle task panicked: {e:#}"),
}
if let Err(e) = async {
let kb_new = open_with_retry("/dev/hidg0").await?;
let ms_new = open_with_retry("/dev/hidg1").await?;
*kb.lock().await = kb_new;
*ms.lock().await = ms_new;
Ok::<(), anyhow::Error>(())
}
.await
{
error!("💥 HID reopen failed: {e:#}");
}
tokio::time::sleep(Duration::from_secs(2)).await;
did_cycle.store(false, Ordering::SeqCst);
});
}
/// Pick the UVC gadget video node.
/// Priority: 1) `LESAVKA_UVC_DEV` override; 2) first `video_output` node.
/// Returns an error when nothing matches instead of guessing a capture card.
@ -120,12 +164,22 @@ fn pick_uvc_device() -> anyhow::Result<String> {
))
}
fn spawn_uvc_control(uvc_dev: &str) -> anyhow::Result<std::process::Child> {
let bin = std::env::var("LESAVKA_UVC_CTRL_BIN")
.unwrap_or_else(|_| "/usr/local/bin/lesavka-uvc".to_string());
Command::new(bin)
.arg("--device")
.arg(uvc_dev)
.spawn()
.context("spawning lesavka-uvc")
}
/*──────────────── Handler ───────────────────*/
struct Handler {
kb: Arc<Mutex<tokio::fs::File>>,
ms: Arc<Mutex<tokio::fs::File>>,
gadget: UsbGadget,
did_cycle: AtomicBool,
did_cycle: Arc<AtomicBool>,
}
impl Handler {
@ -146,7 +200,7 @@ impl Handler {
kb: Arc::new(Mutex::new(kb)),
ms: Arc::new(Mutex::new(ms)),
gadget,
did_cycle: AtomicBool::new(false),
did_cycle: Arc::new(AtomicBool::new(false)),
})
}
@ -176,12 +230,17 @@ impl Relay for Handler {
) -> Result<Response<Self::StreamKeyboardStream>, Status> {
let (tx, rx) = tokio::sync::mpsc::channel(32);
let kb = self.kb.clone();
let ms = self.ms.clone();
let gadget = self.gadget.clone();
let did_cycle = self.did_cycle.clone();
tokio::spawn(async move {
let mut s = req.into_inner();
while let Some(pkt) = s.next().await.transpose()? {
if let Err(e) = kb.lock().await.write_all(&pkt.data).await {
warn!("⌨️ write failed: {e} (dropped)");
recover_hid_if_needed(&e, gadget.clone(), kb.clone(), ms.clone(), did_cycle.clone())
.await;
}
tx.send(Ok(pkt)).await.ok();
}
@ -197,12 +256,17 @@ impl Relay for Handler {
) -> Result<Response<Self::StreamMouseStream>, Status> {
let (tx, rx) = tokio::sync::mpsc::channel(1024);
let ms = self.ms.clone();
let kb = self.kb.clone();
let gadget = self.gadget.clone();
let did_cycle = self.did_cycle.clone();
tokio::spawn(async move {
let mut s = req.into_inner();
while let Some(pkt) = s.next().await.transpose()? {
if let Err(e) = ms.lock().await.write_all(&pkt.data).await {
warn!("🖱️ write failed: {e} (dropped)");
recover_hid_if_needed(&e, gadget.clone(), kb.clone(), ms.clone(), did_cycle.clone())
.await;
}
tx.send(Ok(pkt)).await.ok();
}
@ -337,6 +401,27 @@ async fn main() -> anyhow::Result<()> {
}));
let gadget = UsbGadget::new("lesavka");
let _uvc_ctrl = if std::env::var("LESAVKA_DISABLE_UVC").is_err() {
match pick_uvc_device() {
Ok(uvc_dev) => match spawn_uvc_control(&uvc_dev) {
Ok(child) => {
info!(%uvc_dev, "📷 UVC control helper started");
Some(child)
}
Err(e) => {
warn!("⚠️ failed to start lesavka-uvc: {e:#}");
None
}
},
Err(e) => {
warn!("⚠️ UVC device not ready: {e:#}");
None
}
}
} else {
info!("📷 UVC disabled (LESAVKA_DISABLE_UVC set)");
None
};
let handler = Handler::new(gadget.clone()).await?;
info!("🌐 lesavka-server listening on 0.0.0.0:50051");