#152 Handle Ctrl+C for _run and user commands

src/main.rs

@@ -24,6 +24,7 @@ mod container;
 mod file_util;
 mod path_util;
 mod process_util;
+mod tty_util;
 mod options;
 
 // Commands

src/process_util.rs

@@ -2,14 +2,15 @@ use std::env;
 use std::io::{Read};
 use std::path::{Path, PathBuf};
 
-use libc::getuid;
+use libc::{getuid, getpgrp};
 use nix::sys::signal::{SIGINT, SIGTERM, SIGCHLD};
 use unshare::{Command, Stdio, Fd, ExitStatus, UidMap, GidMap, reap_zombies};
 use signal::trap::Trap;
 
 use config::Settings;
 use container::uidmap::{Uidmap};
 use path_util::PathExt;
+use tty_util::{TtyGuard};
 
 
 pub static DEFAULT_PATH: &'static str =
@@ -19,7 +20,6 @@ pub static PROXY_ENV_VARS: [&'static str; 5] =
     [ "http_proxy", "https_proxy", "ftp_proxy", "all_proxy", "no_proxy" ];
 
 
-
 pub fn capture_stdout(mut cmd: Command) -> Result<Vec<u8>, String> {
     cmd.stdout(Stdio::piped());
     info!("Running {:?}", cmd);
@@ -64,12 +64,18 @@ pub fn capture_fd3_status(mut cmd: Command)
     Ok((status, buf))
 }
 
-pub fn run_and_wait(cmd: &mut Command)
+pub fn run_and_wait(cmd: &mut Command, tty_fd: Option<i32>)
     -> Result<i32, String>
 {
     let mut trap = Trap::trap(&[SIGINT, SIGTERM, SIGCHLD]);
     info!("Running {:?}", cmd);
-    let child = try!(cmd.spawn().map_err(|e| format!("{}", e)));
+    let child = try!(cmd.spawn()
+                     .map_err(|e| format!("Error running {:?}: {}", cmd, e)));
+    let pgrp = unsafe { getpgrp() };
+    let tty_guard = match tty_fd {
+        Some(tty_fd) => Some(try!(TtyGuard::new(tty_fd, pgrp))),
+        None => None,
+    };
 
     for signal in trap.by_ref() {
         match signal {
@@ -82,13 +88,30 @@ pub fn run_and_wait(cmd: &mut Command)
                 // SIGTERM is usually sent to a specific process so we
                 // forward it to children
                 debug!("Received SIGTERM signal, propagating");
-                child.signal(SIGTERM).ok();
+                try!(child.signal(SIGTERM)
+                     .map_err(|e| format!(
+                         "Error when sending SIGTERM
+                          signal to {:?}: {}", cmd, e)));
             }
             SIGCHLD => {
-                for (pid, status) in reap_zombies() {
-                    if pid == child.pid() {
-                        return Ok(convert_status(status));
-                    }
+                match tty_guard {
+                    Some(ref tty_guard) => {
+                        match try!(tty_guard.wait_child(&cmd, &child)) {
+                            Some(st) => {
+                                return Ok(convert_status(st));
+                            },
+                            None => {
+                                continue;
+                            },
+                        }
+                    },
+                    None => {
+                        for (pid, status) in reap_zombies() {
+                            if pid == child.pid() {
+                                return Ok(convert_status(status));
+                            }
+                        }
+                    },
                 }
             }
             _ => unreachable!(),

src/tty_util.rs

@@ -0,0 +1,128 @@
+use libc::{c_int, pid_t};
+use libc::{signal};
+use libc::STDIN_FILENO;
+use nix;
+use nix::errno::EINTR;
+use nix::sys::ioctl::ioctl;
+use nix::sys::signal::{SIGCONT, SIGTTIN, SIGTTOU};
+use nix::sys::wait::{waitpid, WaitStatus, WNOHANG, WUNTRACED};
+use nix::unistd::{isatty, getpid, setpgid};
+
+use unshare::{Child, Command, ExitStatus};
+
+
+mod ffi {
+    use libc::{c_ulong, pid_t, sighandler_t};
+
+    pub static WAIT_ANY: pid_t = -1;
+
+    pub static SIG_IGN: sighandler_t = 1;
+    pub static SIG_ERR: sighandler_t = !0;
+
+    pub static TIOCSPGRP: c_ulong = 21520;
+}
+
+
+pub struct TtyGuard {
+    tty_fd: c_int,
+    pgrp: pid_t,
+}
+
+impl TtyGuard {
+    pub fn new(tty_fd: c_int, pgrp: pid_t) -> Result<TtyGuard, String> {
+        try!(give_tty_to(tty_fd, pgrp));
+        Ok(TtyGuard {
+            tty_fd: tty_fd,
+            pgrp: pgrp,
+        })
+    }
+
+    pub fn wait_child(&self, cmd: &Command, child: &Child)
+        -> Result<Option<ExitStatus>, String>
+    {
+        loop {
+            match waitpid(ffi::WAIT_ANY, Some(WNOHANG | WUNTRACED)) {
+                Ok(WaitStatus::Stopped(child_pid, signum)) => {
+                    if child_pid == child.pid() && (signum == SIGTTOU || signum == SIGTTIN) {
+                        try!(give_tty_to(self.tty_fd, child.pid()));
+                        try!(child.signal(SIGCONT)
+                             .map_err(|e| format!(
+                                 "Error when sending SIGCONT
+                                  signal to {:?}: {}", cmd, e)));
+                    }
+                    continue;
+                },
+                Ok(WaitStatus::Continued(_)) => {
+                    continue;
+                },
+                Ok(WaitStatus::Exited(child_pid, st)) => {
+                    if child_pid == child.pid() {
+                        return Ok(Some(ExitStatus::Exited(st)));
+                    }
+                    continue;
+                },
+                Ok(WaitStatus::Signaled(child_pid, signum, core)) => {
+                    if child_pid == child.pid() {
+                        return Ok(Some(ExitStatus::Signaled(signum, core)));
+                    }
+                    continue;
+                },
+                Ok(WaitStatus::StillAlive) => {
+                    return Ok(None);
+                },
+                Err(nix::Error::Sys(EINTR)) => {
+                    continue;
+                },
+                Err(e) => {
+                    return Err(
+                        format!("Error when waiting for {:?}: {}", cmd, e));
+                },
+            }
+        }
+    }
+}
+
+impl Drop for TtyGuard {
+    fn drop(&mut self) {
+        let _ = give_tty_to(self.tty_fd, self.pgrp);
+    }
+}
+
+pub fn prepare_tty() -> Result<Option<c_int>, String> {
+    let tty_fd = STDIN_FILENO;
+    let is_interactive = isatty(tty_fd).unwrap_or(false);
+    if is_interactive {
+        try!(ignore_tty_signals());
+        let pid = getpid();
+        try!(setpgid(pid, pid).map_err(|e| format!("{}", e)));
+        try!(give_tty_to(tty_fd, pid));
+        Ok(Some(tty_fd))
+    } else {
+        Ok(None)
+    }
+}
+
+pub fn give_tty_to(fd: c_int, pgrp: pid_t) -> Result<(), String> {
+    let res = unsafe { ioctl(fd, ffi::TIOCSPGRP, &pgrp) };
+    match res {
+        res if res < 0 => Err(
+            format!("Error when giving tty with fd {} to process group {}",
+                    fd, pgrp)),
+        _ => Ok(()),
+    }
+}
+
+pub fn ignore_tty_signals() -> Result<(), String> {
+    try!(ignore_signal(SIGTTIN));
+    try!(ignore_signal(SIGTTOU));
+    Ok(())
+}
+
+fn ignore_signal(signum: i32) -> Result<(), String> {
+    let res = unsafe { signal(signum, ffi::SIG_IGN) };
+    if res == ffi::SIG_ERR {
+        return Err(
+            format!("Error when setting signal handler for signum: {}", signum));
+    }
+    Ok(())
+}

src/wrapper/commandline.rs

@@ -19,7 +19,7 @@ use process_util::{run_and_wait, set_uidmap};
 
 
 pub fn commandline_cmd(command: &CommandInfo,
-    wrapper: &Wrapper, mut cmdline: Vec<String>)
+    wrapper: &Wrapper, mut cmdline: Vec<String>, tty_fd: Option<i32>)
     -> Result<i32, String>
 {
     if command.run.len() == 0 {
@@ -99,6 +99,9 @@ pub fn commandline_cmd(command: &CommandInfo,
         cmd.env(k, v);
     }
 
-    run_and_wait(&mut cmd)
-    .map_err(|e| format!("Error running {:?}: {}", cmd, e))
+    if let Some(_) = tty_fd {
+        cmd.make_group_leader(true);
+    }
+
+    run_and_wait(&mut cmd, tty_fd)
 }

src/wrapper/mod.rs

@@ -8,6 +8,7 @@ use argparse::{ArgumentParser, Store, StoreOption, List};
 use super::config::{find_config, Config, Settings};
 use super::config::command::MainCommand::{Command, Supervise};
 use config::read_settings::{read_settings, MergedSettings};
+use tty_util::{prepare_tty};
 
 
 mod debug;
@@ -80,6 +81,14 @@ pub fn run() -> i32 {
         }
     };
 
+    let tty_fd = match prepare_tty() {
+        Ok(tty_fd) => tty_fd,
+        Err(e) => {
+            writeln!(&mut err, "{}", e).ok();
+            return 121;
+        },
+    };
+
     let wrapper = Wrapper {
         root: root,
         config: &config,
@@ -94,14 +103,14 @@ pub fn run() -> i32 {
         "_build_shell" => Ok(debug::run_interactive_build_shell(&wrapper)),
         "_build" => build::build_container_cmd(&wrapper, args),
         "_version_hash" => build::print_version_hash_cmd(&wrapper, args),
-        "_run" => run::run_command_cmd(&wrapper, args, true),
-        "_run_in_netns" => run::run_command_cmd(&wrapper, args, false),
+        "_run" => run::run_command_cmd(&wrapper, args, true, tty_fd),
+        "_run_in_netns" => run::run_command_cmd(&wrapper, args, false, tty_fd),
         "_clean" => clean::clean_cmd(&wrapper, args),
         "_pack_image" => pack::pack_image_cmd(&wrapper, args),
         _ => {
             match config.commands.get(&cmd) {
                 Some(&Command(ref cmd_info)) => {
-                    commandline::commandline_cmd(cmd_info, &wrapper, args)
+                    commandline::commandline_cmd(cmd_info, &wrapper, args, tty_fd)
                 }
                 Some(&Supervise(ref svc_info)) => {
                     supervise::supervise_cmd(&cmd, svc_info, &wrapper, args)

src/wrapper/run.rs

@@ -12,10 +12,11 @@ use container::uidmap::{map_users};
 use super::setup;
 use super::Wrapper;
 use path_util::PathExt;
-use process_util::{convert_status, set_uidmap, copy_env_vars};
+use process_util::{set_uidmap, copy_env_vars, run_and_wait};
 
 
-pub fn run_command_cmd(wrapper: &Wrapper, cmdline: Vec<String>, user_ns: bool)
+pub fn run_command_cmd(wrapper: &Wrapper,
+    cmdline: Vec<String>, user_ns: bool, tty_fd: Option<i32>)
     -> Result<i32, String>
 {
     let mut container: String = "".to_string();
@@ -110,8 +111,9 @@ pub fn run_command_cmd(wrapper: &Wrapper, cmdline: Vec<String>, user_ns: bool)
         cmd.env(k.to_string(), v.to_string());
     }
 
-    match cmd.status() {
-        Ok(s) => Ok(convert_status(s)),
-        Err(e) => Err(format!("Error running {:?}: {}", cmd, e)),
+    if let Some(_) = tty_fd {
+        cmd.make_group_leader(true);
     }
+
+    run_and_wait(&mut cmd, tty_fd)
 }

src/wrapper/supervise.rs

@@ -135,6 +135,6 @@ fn supervise_child_command(cmdname: &String, name: &String, bridge: bool,
         cmd.env(k, v);
     }
 
-    run_and_wait(&mut cmd)
+    run_and_wait(&mut cmd, None)
     .map_err(|e| format!("Error running {:?}: {}", cmd, e))
 }