use anyhow::anyhow;
use clap::Parser;
use tokio::io::{AsyncReadExt, AsyncWriteExt};
use tokio_listener::{self, SystemOptions, UserOptions};
use tracing::{debug, error, info, instrument, Level};
use nix_compat::wire::{
bytes, primitive,
worker_protocol::{self, ClientSettings},
};
#[derive(Parser, Debug)]
struct Cli {
/// Listening unix socket path
#[arg(short, long)]
socket: Option<String>,
/// Log verbosity level. Can be "error", "warn", "info", "debug", "trace", or a number 1-5
#[arg(short, long, env)]
verbosity: Option<Level>,
}
/// Structure used to hold the client socket connection and some
/// metadata about the connection.
#[derive(Debug)]
struct ClientConnection<R: AsyncReadExt + AsyncWriteExt + Unpin> {
conn: R,
version_minor: u64,
client_settings: Option<ClientSettings>,
}
#[tokio::main]
#[instrument()]
async fn main() {
let args = Cli::parse();
tracing_subscriber::fmt()
.compact()
.with_max_level(
args.verbosity
.unwrap_or_else(|| panic!("Can't parse log verbosity")),
)
.try_init()
.unwrap();
info!("Started Tvix daemon");
let addr = args
.socket
.unwrap_or_else(|| "sd_listen_unix".to_string())
.parse()
.expect("Invalid listening socket address");
let system_options: SystemOptions = Default::default();
let mut user_options: UserOptions = Default::default();
user_options.recv_buffer_size = Some(1024);
user_options.send_buffer_size = Some(1024);
info!(user_options.send_buffer_size);
info!(user_options.recv_buffer_size);
let mut listener = tokio_listener::Listener::bind(&addr, &system_options, &user_options)
.await
.unwrap();
info!(listener_address = ?listener, "Listening for incoming connections");
while let Ok((conn, addr)) = listener.accept().await {
info!(addr = %addr, "Incoming connection");
tokio::spawn(async move { worker(conn).await });
}
}
/// Worker in charge to respond a Nix client using the Nix wire
/// protocol.
#[instrument()]
async fn worker<R>(mut conn: R)
where
R: AsyncReadExt + AsyncWriteExt + Unpin + std::fmt::Debug,
{
match perform_init_handshake(&mut conn).await {
Ok(mut client_connection) => {
debug!("Client hanshake succeeded");
// TODO: implement logging. For now, we'll just send
// STDERR_LAST, which is good enough to get Nix respond to
// us.
primitive::write_u64(&mut client_connection.conn, worker_protocol::STDERR_LAST)
.await
.unwrap();
loop {
let op = worker_protocol::read_op(&mut client_connection.conn)
.await
.unwrap();
match op {
worker_protocol::Operation::SetOptions => {
let settings = op_set_options(&mut client_connection).await.unwrap();
client_connection.client_settings = Some(settings);
debug!(settings = ?client_connection.client_settings, "Received client settings");
}
_ => {
error!(op = ?op, "Unimplemented operation");
break;
}
}
}
}
Err(e) => error!("Client handshake failed: {}", e),
}
}
async fn op_set_options<R>(conn: &mut ClientConnection<R>) -> std::io::Result<ClientSettings>
where
R: AsyncReadExt + AsyncWriteExt + Unpin + std::fmt::Debug,
{
let settings =
worker_protocol::read_client_settings(&mut conn.conn, conn.version_minor).await?;
// The client expects us to send some logs when we're processing
// the settings. Sending STDERR_LAST signal we're done processing.
primitive::write_u64(&mut conn.conn, worker_protocol::STDERR_LAST).await?;
Ok(settings)
}
/// Performs the initial handshake. During the handshake, the client
/// will first send a magic u64, to which the daemon needs to respond
/// with another magic u64.
///
/// We then retrieve the client version, and discard a bunch of now
/// obsolete data.
#[instrument()]
async fn perform_init_handshake<'a, R: 'a>(
mut conn: &'a mut R,
) -> anyhow::Result<ClientConnection<&'a mut R>>
where
&'a mut R: AsyncReadExt + AsyncWriteExt + Unpin + std::fmt::Debug,
{
let mut magic_hello = vec![0; 8];
conn.read_exact(&mut magic_hello).await?;
debug!("Hello read");
if magic_hello != worker_protocol::MAGIC_HELLO {
Err(anyhow!(
"Invalid client hello received: {:?}, expected {:?}",
magic_hello,
worker_protocol::MAGIC_HELLO
))
} else {
conn.write_all(&worker_protocol::MAGIC_HELLO_RESPONSE[..])
.await?;
conn.write_all(&worker_protocol::PROTOCOL_VERSION[..])
.await?;
conn.flush().await?;
debug!("Hello responded");
let client_version = primitive::read_u64(&mut conn).await?;
debug!("Version read");
if client_version < 0x10a {
return Err(anyhow!("The nix client version is too old"));
}
let protocol_minor = client_version & 0x00ff;
let protocol_major = client_version & 0xff00;
debug!(client.version = %client_version, client.minor = %protocol_minor, client.major = %protocol_major);
if protocol_minor >= 14 {
debug!("read cpu affinity");
// Obsolete CPU affinity.
let read_affinity = primitive::read_u64(&mut conn).await?;
if read_affinity != 0 {
skip_8_bytes(&mut conn).await?;
};
}
if protocol_minor >= 11 {
// Obsolete reserveSpace
debug!("read reservespace");
skip_8_bytes(&mut conn).await?;
}
if protocol_minor >= 33 {
// Nix version. We're plain lying, we're not Nix, but eh…
// Setting it to the 2.3 lineage. Not 100% sure this is a
// good idea.
debug!("write version");
// Plain str padded to 64 bits.
bytes::write_bytes(&mut conn, "2.3.17").await?;
conn.flush().await?;
}
if protocol_minor >= 35 {
worker_protocol::write_worker_trust_level(&mut conn, worker_protocol::Trust::Trusted)
.await?;
info!("Trust sent");
}
Ok(ClientConnection {
conn,
version_minor: protocol_minor,
client_settings: None,
})
}
}
async fn skip_8_bytes<R>(conn: &mut R) -> anyhow::Result<()>
where
R: AsyncReadExt + Unpin + std::fmt::Debug,
{
let mut _discard_buffer = [0; 8];
conn.read_exact(&mut _discard_buffer).await?;
Ok(())
}
#[cfg(test)]
mod integration_tests {
use nix_compat::wire::worker_protocol;
#[tokio::test]
async fn test_init_handshake() {
let mut test_conn = tokio_test::io::Builder::new()
.read(&worker_protocol::MAGIC_HELLO)
.write(&worker_protocol::MAGIC_HELLO_RESPONSE)
.write(&worker_protocol::PROTOCOL_VERSION)
// Let's say the client is in sync with the daemon
// protocol-wise
.read(&worker_protocol::PROTOCOL_VERSION)
// cpu affinity
.read(&vec![0; 8])
// reservespace
.read(&vec![0; 8])
// version (size)
.write(&vec![0x06, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00])
// version (data == 2.2.17 + padding)
.write(&vec![50, 46, 51, 46, 49, 55, 0, 0])
// Trusted (1 == client trusted
.write(&vec![1, 0, 0, 0, 0, 0, 0, 0])
.build();
crate::perform_init_handshake(&mut test_conn).await.unwrap();
}
}
