Merge pull request #89 from utam0k/tty-refactor

clean up around the tty.

Author: Furisto

Diff for: src/cgroups/v2/manager.rs

@@ -102,7 +102,7 @@ impl Manager {
         Ok(controllers)
     }
 
-    fn write_controllers(path: &Path, controllers: &Vec<String>) -> Result<()> {
+    fn write_controllers(path: &Path, controllers: &[String]) -> Result<()> {
         for controller in controllers {
             common::write_cgroup_file_str(path.join(CGROUP_SUBTREE_CONTROL), controller)?;
         }

Diff for: src/create.rs

@@ -33,7 +33,7 @@ pub struct Create {
     bundle: PathBuf,
     /// Unix socket (file) path , which will receive file descriptor of the writing end of the pseudoterminal
     #[clap(short, long)]
-    console_socket: Option<String>,
+    console_socket: Option<PathBuf>,
     /// name of the container instance to be started
     pub container_id: String,
 }
@@ -86,16 +86,13 @@ impl Create {
         let mut notify_socket: NotifyListener = NotifyListener::new(&container_dir)?;
         // convert path of root file system of the container to absolute path
         let rootfs = fs::canonicalize(&spec.root.path)?;
+
         // if socket file path is given in commandline options,
-        // get file descriptors of console and console socket
-        let (csocketfd, _consolefd) = {
-            if let Some(console_socket) = &self.console_socket {
-                let (csocketfd, consolefd) =
-                    tty::load_console_sockets(&container_dir, console_socket)?;
-                (Some(csocketfd), Some(consolefd))
-            } else {
-                (None, None)
-            }
+        // get file descriptors of console socket
+        let csocketfd = if let Some(console_socket) = &self.console_socket {
+            Some(tty::setup_console_socket(&container_dir, console_socket)?)
+        } else {
+            None
         };
 
         let process = run_container(
@@ -162,7 +159,7 @@ fn run_container<P: AsRef<Path>>(
 
             // set up tty if specified
             if let Some(csocketfd) = csocketfd {
-                tty::ready(csocketfd)?;
+                tty::setup_console(csocketfd)?;
             }
 
             // set namespaces

Diff for: src/main.rs

@@ -2,7 +2,6 @@
 //! Container Runtime written in Rust, inspired by [railcar](https://github.com/oracle/railcar)
 //! This crate provides a container runtime which can be used by a high-level container runtime to run containers.
 
-use procfs;
 use std::fs;
 use std::path::{Path, PathBuf};
 

Diff for: src/namespaces.rs

@@ -3,7 +3,7 @@
 //! Process (processes in a namespace have two PIDs, one for the global PID,
 //! which is used by the main system and the second one is for the child within the process tree),
 //! Interprocess Communication (Control or communication between processes),
-//! Network (which network devices can be seen by the processes in the namespace), User (User configs), 
+//! Network (which network devices can be seen by the processes in the namespace), User (User configs),
 //! UTS (hostname and domain information, processes will think they're running on servers with different names),
 //! Cgroup (Resource limits, execution priority etc.)
 

Diff for: src/tty.rs

@@ -6,44 +6,21 @@ use std::path::Path;
 
 use anyhow::{bail, Result};
 use nix::errno::Errno;
-use nix::fcntl;
 use nix::sys::socket;
-use nix::sys::stat;
+use nix::sys::uio;
 use nix::unistd::{close, setsid};
 
 use crate::stdio;
 use crate::stdio::FileDescriptor;
 
-pub fn ready(console_fd: FileDescriptor) -> Result<()> {
-    let openpty_result = nix::pty::openpty(None, None)?;
-    let data: &[u8] = b"/dev/ptmx";
-    let iov = [nix::sys::uio::IoVec::from_slice(data)];
-    let fds = [openpty_result.master];
-    let cmsg = socket::ControlMessage::ScmRights(&fds);
-    socket::sendmsg(
-        console_fd.as_raw_fd(),
-        &iov,
-        &[cmsg],
-        socket::MsgFlags::empty(),
-        None,
-    )?;
+// TODO: Handling when there isn't console-socket.
 
-    setsid()?;
-    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");
-    close(console_fd.as_raw_fd())?;
-    Ok(())
-}
-
-pub fn load_console_sockets(
+pub fn setup_console_socket(
     container_dir: &Path,
-    console_socket: &str,
-) -> Result<(FileDescriptor, FileDescriptor)> {
-    let csocket = "console-stdout";
-    symlink(console_socket, container_dir.join(csocket))?;
+    console_socket_path: &Path,
+) -> Result<FileDescriptor> {
+    let csocket = "console-socket";
+    symlink(console_socket_path, container_dir.join(csocket))?;
 
     let mut csocketfd = socket::socket(
         socket::AddressFamily::Unix,
@@ -63,19 +40,31 @@ pub fn load_console_sockets(
         }
         Ok(()) => csocketfd,
     };
-    let console = "console";
-    let consolefd = match fcntl::open(
-        &*console,
-        fcntl::OFlag::O_NOCTTY | fcntl::OFlag::O_RDWR,
-        stat::Mode::empty(),
-    ) {
-        Err(e) => {
-            if e != ::nix::Error::Sys(Errno::ENOENT) {
-                bail!("failed to open {}", console);
-            }
-            -1
-        }
-        Ok(fd) => fd,
+    Ok(csocketfd.into())
+}
+
+pub fn setup_console(console_fd: FileDescriptor) -> 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 = nix::pty::openpty(None, None)?;
+    let pty_name: &[u8] = b"/dev/ptmx";
+    let iov = [uio::IoVec::from_slice(pty_name)];
+    let fds = [openpty_result.master];
+    let cmsg = socket::ControlMessage::ScmRights(&fds);
+    socket::sendmsg(
+        console_fd.as_raw_fd(),
+        &iov,
+        &[cmsg],
+        socket::MsgFlags::empty(),
+        None,
+    )?;
+
+    setsid()?;
+    if unsafe { libc::ioctl(openpty_result.slave, libc::TIOCSCTTY) } < 0 {
+        log::warn!("could not TIOCSCTTY");
     };
-    Ok((csocketfd.into(), consolefd.into()))
+    let slave = FileDescriptor::from(openpty_result.slave);
+    stdio::connect_stdio(&slave, &slave, &slave).expect("could not dup tty to stderr");
+    close(console_fd.as_raw_fd())?;
+    Ok(())
 }

Diff for: src/utils.rs

@@ -46,13 +46,10 @@ pub fn do_exec(path: impl AsRef<Path>, args: &[String], envs: &[String]) -> Resu
     env::vars().for_each(|(key, _value)| std::env::remove_var(key));
     // set env vars
     envs.iter().for_each(|e| {
-        let mut split = e.split("=");
-        match split.next() {
-            Some(key) => {
-                let value: String = split.collect::<Vec<&str>>().join("=");
-                env::set_var(key, value)
-            }
-            None => {}
+        let mut split = e.split('=');
+        if let Some(key) = split.next() {
+            let value: String = split.collect::<Vec<&str>>().join("=");
+            env::set_var(key, value)
         };
     });