delete the original FileDescriptor.

src/container/builder_impl.rs

@@ -1,13 +1,12 @@
 use anyhow::{Context, Result};
 use oci_spec::Spec;
-use std::{fs, path::PathBuf};
+use std::{fs, os::unix::prelude::RawFd, path::PathBuf};
 
 use crate::{
     cgroups,
     namespaces::Namespaces,
     process::{child, fork, init, parent},
     rootless::Rootless,
-    stdio::FileDescriptor,
     syscall::linux::LinuxSyscall,
     utils,
 };
@@ -31,7 +30,7 @@ pub(super) struct ContainerBuilderImpl<'a> {
     /// container process to the higher level runtime
     pub pid_file: Option<PathBuf>,
     /// Socket to communicate the file descriptor of the ptty
-    pub console_socket: Option<FileDescriptor>,
+    pub console_socket: Option<RawFd>,
     /// Options for rootless containers
     pub rootless: Option<Rootless<'a>>,
     /// Path to the Unix Domain Socket to communicate container start
@@ -69,7 +68,7 @@ impl<'a> ContainerBuilderImpl<'a> {
             syscall: self.syscall.clone(),
             spec: self.spec.clone(),
             rootfs: self.rootfs.clone(),
-            console_socket: self.console_socket.clone(),
+            console_socket: self.console_socket,
             is_rootless: self.rootless.is_some(),
             notify_path: self.notify_path.clone(),
             preserve_fds: self.preserve_fds,

src/container/tenant_builder.rs

@@ -8,14 +8,12 @@ use std::{
     convert::TryFrom,
     ffi::{CString, OsString},
     fs,
-    os::unix::prelude::OsStrExt,
+    os::unix::prelude::{OsStrExt, RawFd},
     path::{Path, PathBuf},
     str::FromStr,
 };
 
-use crate::{
-    notify_socket::NotifySocket, rootless::detect_rootless, stdio::FileDescriptor, tty, utils,
-};
+use crate::{notify_socket::NotifySocket, rootless::detect_rootless, tty, utils};
 
 use super::{builder::ContainerBuilder, builder_impl::ContainerBuilderImpl, Container};
 
@@ -308,7 +306,7 @@ impl TenantContainerBuilder {
         Ok(socket_path)
     }
 
-    fn setup_tty_socket(&self, container_dir: &Path) -> Result<Option<FileDescriptor>> {
+    fn setup_tty_socket(&self, container_dir: &Path) -> Result<Option<RawFd>> {
         let tty_name = Self::generate_name(container_dir, TENANT_TTY);
         let csocketfd = if let Some(console_socket) = &self.base.console_socket {
             Some(tty::setup_console_socket(

src/lib.rs

@@ -15,7 +15,6 @@ pub mod process;
 pub mod rootfs;
 pub mod rootless;
 pub mod signal;
-pub mod stdio;
 pub mod syscall;
 pub mod tty;
 pub mod utils;

src/process/init.rs

@@ -4,7 +4,10 @@ use nix::{
     unistd::{Gid, Uid},
 };
 use oci_spec::Spec;
-use std::{env, os::unix::io::AsRawFd};
+use std::{
+    env,
+    os::unix::{io::AsRawFd, prelude::RawFd},
+};
 use std::{fs, io::Write, path::Path, path::PathBuf};
 
 use crate::{
@@ -13,7 +16,6 @@ use crate::{
     notify_socket::NotifyListener,
     process::child,
     rootfs,
-    stdio::FileDescriptor,
     syscall::{linux::LinuxSyscall, Syscall},
     tty, utils,
 };
@@ -93,7 +95,7 @@ pub struct ContainerInitArgs {
     /// Root filesystem of the container
     pub rootfs: PathBuf,
     /// Socket to communicate the file descriptor of the ptty
-    pub console_socket: Option<FileDescriptor>,
+    pub console_socket: Option<RawFd>,
     /// Options for rootless containers
     pub is_rootless: bool,
     /// Path to the Unix Domain Socket to communicate container start

src/tty.rs

@@ -2,25 +2,27 @@
 
 use std::os::unix::fs::symlink;
 use std::os::unix::io::AsRawFd;
+use std::os::unix::prelude::RawFd;
 use std::path::Path;
 
 use anyhow::Context;
 use anyhow::{bail, Result};
 use nix::errno::Errno;
 use nix::sys::socket;
 use nix::sys::uio;
+use nix::unistd::dup2;
 use nix::unistd::{close, setsid};
 
-use crate::stdio;
-use crate::stdio::FileDescriptor;
+const STDIN: i32 = 0;
+const STDOUT: i32 = 1;
+const STDERR: i32 = 2;
 
 // TODO: Handling when there isn't console-socket.
-
 pub fn setup_console_socket(
     container_dir: &Path,
     console_socket_path: &Path,
     socket_name: &str,
-) -> Result<FileDescriptor> {
+) -> Result<RawFd> {
     let linked = container_dir.join(socket_name);
     symlink(console_socket_path, &linked)?;
 
@@ -42,10 +44,10 @@ pub fn setup_console_socket(
         }
         Ok(()) => csocketfd,
     };
-    Ok(csocketfd.into())
+    Ok(csocketfd)
 }
 
-pub fn setup_console(console_fd: &FileDescriptor) -> Result<()> {
+pub fn setup_console(console_fd: &RawFd) -> Result<()> {
     // You can also access pty master, but it is better to use the API.
     // ref. https://github.com/containerd/containerd/blob/261c107ffc4ff681bc73988f64e3f60c32233b37/vendor/github.com/containerd/go-runc/console.go#L139-L154
     let openpty_result =
@@ -67,12 +69,21 @@ pub fn setup_console(console_fd: &FileDescriptor) -> Result<()> {
     if unsafe { libc::ioctl(openpty_result.slave, libc::TIOCSCTTY) } < 0 {
         log::warn!("could not TIOCSCTTY");
     };
-    let slave = FileDescriptor::from(openpty_result.slave);
-    stdio::connect_stdio(&slave, &slave, &slave).expect("could not dup tty to stderr");
+    let slave = openpty_result.slave;
+    connect_stdio(&slave, &slave, &slave).context("could not dup tty to stderr")?;
     close(console_fd.as_raw_fd()).context("could not close console socket")?;
     Ok(())
 }
 
+fn connect_stdio(stdin: &RawFd, stdout: &RawFd, stderr: &RawFd) -> Result<()> {
+    dup2(stdin.as_raw_fd(), STDIN)?;
+    dup2(stdout.as_raw_fd(), STDOUT)?;
+    // FIXME: Rarely does it fail.
+    // error message: `Error: Resource temporarily unavailable (os error 11)`
+    dup2(stderr.as_raw_fd(), STDERR)?;
+    Ok(())
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;