Set close-on-exec flag for socket in async server

The UnixListener and VsockListener do not set the socket close-on-exec
by default, we must do it manually.

Signed-off-by: Tim Zhang <[email protected]>

Author: Tim-Zhang

src/asynchronous/server.rs

@@ -16,7 +16,7 @@ use crate::ttrpc::{Code, Request};
 use crate::MessageHeader;
 use futures::StreamExt as _;
 use std::marker::Unpin;
-use std::os::unix::io::FromRawFd;
+use std::os::unix::io::{AsRawFd, FromRawFd};
 use std::os::unix::net::UnixListener as SysUnixListener;
 use tokio::{
     self,
@@ -118,11 +118,12 @@ impl Server {
     pub async fn do_start<I, S>(&self, listenfd: RawFd, mut incoming: I) -> Result<()>
     where
         I: Stream<Item = std::io::Result<S>> + Unpin,
-        S: AsyncRead + AsyncWrite + Send + 'static,
+        S: AsyncRead + AsyncWrite + AsRawFd + Send + 'static,
     {
         while let Some(result) = incoming.next().await {
             match result {
                 Ok(stream) => {
+                    common::set_fd_close_exec(stream.as_raw_fd())?;
                     let methods = self.methods.clone();
                     tokio::spawn(async move {
                         let (mut reader, mut writer) = split(stream);

src/common.rs

@@ -8,7 +8,7 @@
 #![allow(unused_macros)]
 
 use crate::error::{Error, Result};
-use nix::fcntl::{fcntl, FcntlArg, OFlag};
+use nix::fcntl::{fcntl, FcntlArg, FdFlag, OFlag};
 use nix::sys::socket::*;
 use std::os::unix::io::RawFd;
 use std::str::FromStr;
@@ -54,6 +54,16 @@ pub fn parse_host(host: &str) -> Result<(Domain, Vec<&str>)> {
     Ok((domain, hostv))
 }
 
+pub fn set_fd_close_exec(fd: RawFd) -> Result<RawFd> {
+    if let Err(e) = fcntl(fd, FcntlArg::F_SETFD(FdFlag::FD_CLOEXEC)) {
+        return Err(Error::Others(format!(
+            "failed to set fd: {} as close-on-exec: {}",
+            fd, e
+        )));
+    }
+    Ok(fd)
+}
+
 pub fn do_bind(host: &str) -> Result<(RawFd, Domain)> {
     let (domain, hostv) = parse_host(host)?;