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|
mod init;
mod jobserver;
mod ns;
mod paths;
mod tar;
mod task;
mod util;
use std::{
collections::HashSet,
fs::File,
net,
os::unix::{net::UnixStream, prelude::*},
process, slice,
};
use capctl::prctl;
use nix::{
errno::Errno,
poll,
sched::CloneFlags,
sys::{signal, signalfd::SignalFd, stat, wait},
unistd::{self, Gid, Pid, Uid},
};
use uds::UnixSeqpacketConn;
use common::{error::*, types::*};
use jobserver::Jobserver;
use util::{checkable::Checkable, clone, steal::Steal, unix};
#[derive(Debug, Clone)]
pub struct Options {
pub jobs: Option<usize>,
}
#[derive(Debug)]
struct RunnerContext {
socket: Steal<UnixSeqpacketConn>,
jobserver: Jobserver,
tasks: HashSet<Pid>,
}
fn handle_sigchld(ctx: &mut RunnerContext) -> Result<()> {
loop {
let status = match wait::waitpid(Pid::from_raw(-1), Some(wait::WaitPidFlag::WNOHANG)) {
Ok(wait::WaitStatus::StillAlive) | Err(Errno::ECHILD) => return Ok(()),
res => res.expect("waitpid()"),
};
let pid = status.pid().unwrap();
if ctx.tasks.remove(&pid) {
status.check()?;
}
}
}
fn handle_request(ctx: &mut RunnerContext, request_socket: UnixStream) {
let run = || {
ctx.socket.steal();
let task: Task =
bincode::deserialize_from(&request_socket).expect("Failed to decode task description");
prctl::set_name(&task.label).expect("prctl(PR_SET_NAME)");
let result = task::handle(task, &mut ctx.jobserver);
bincode::serialize_into(&request_socket, &result).expect("Failed to send task result");
drop(request_socket);
};
let pid = unsafe { clone::spawn(None, run) }.expect("fork()");
assert!(ctx.tasks.insert(pid));
}
fn handle_socket(ctx: &mut RunnerContext) -> bool {
let mut fd = 0;
match ctx
.socket
.recv_fds(&mut [0], slice::from_mut(&mut fd))
.expect("recv_fds()")
{
(1, _, n_fd) => {
assert!(n_fd == 1);
}
_ => return false,
}
let request_socket = unsafe { UnixStream::from_raw_fd(fd) };
handle_request(ctx, request_socket);
true
}
fn runner(uid: Uid, gid: Gid, socket: UnixSeqpacketConn, _lockfile: File, options: &Options) -> ! {
ns::mount_proc();
ns::setup_userns(Uid::from_raw(0), Gid::from_raw(0), uid, gid);
stat::umask(stat::Mode::from_bits_truncate(0o022));
init::init_runner().unwrap();
let jobs = options
.jobs
.unwrap_or_else(|| unix::nproc().expect("Failed to get number of available CPUs"));
let jobserver = Jobserver::new(jobs).expect("Failed to initialize jobserver pipe");
let mut ctx = RunnerContext {
socket: socket.into(),
jobserver,
tasks: HashSet::new(),
};
let mut signals = signal::SigSet::empty();
signals.add(signal::Signal::SIGCHLD);
signal::pthread_sigmask(signal::SigmaskHow::SIG_BLOCK, Some(&signals), None)
.expect("pthread_sigmask()");
let mut sfd = SignalFd::new(&signals).expect("Failed to create signal file descriptor");
let mut pollfds = [
poll::PollFd::new(sfd.as_raw_fd(), poll::PollFlags::POLLIN),
poll::PollFd::new(ctx.socket.as_raw_fd(), poll::PollFlags::POLLIN),
];
loop {
poll::poll(&mut pollfds, -1).expect("poll()");
let events = pollfds[0]
.revents()
.expect("Unknown events in poll() return");
if events.contains(poll::PollFlags::POLLIN) {
let _signal = sfd.read_signal().expect("read_signal()").unwrap();
handle_sigchld(&mut ctx).expect("Task process exited abnormally");
} else if events.intersects(!poll::PollFlags::POLLIN) {
panic!("Unexpected error status for signal file descriptor");
}
let events = pollfds[1]
.revents()
.expect("Unknown events in poll() return");
if events.contains(poll::PollFlags::POLLIN) {
if !handle_socket(&mut ctx) {
break;
}
} else if events.intersects(!poll::PollFlags::POLLIN) {
panic!("Unexpected error status for socket file descriptor");
}
}
process::exit(0);
}
pub struct Runner {
socket: UnixSeqpacketConn,
}
impl Runner {
/// Creates a new container runner
///
/// # Safety
///
/// Do not call in multithreaded processes.
pub unsafe fn new(options: &Options) -> Result<Self> {
let lockfile = unix::lock(paths::LOCKFILE, true, false)
.context("Failed to get lock on build directory, is another instance running?")?;
let uid = unistd::geteuid();
let gid = unistd::getegid();
let (local, remote) = UnixSeqpacketConn::pair().expect("socketpair()");
match clone::clone(
CloneFlags::CLONE_NEWUSER | CloneFlags::CLONE_NEWNS | CloneFlags::CLONE_NEWPID,
)
.expect("clone()")
{
unistd::ForkResult::Parent { .. } => Ok(Runner { socket: local }),
unistd::ForkResult::Child => {
drop(local);
runner(uid, gid, remote, lockfile, options);
}
}
}
pub fn spawn(&self, task: &Task) -> UnixStream {
let (local, remote) = UnixStream::pair().expect("socketpair()");
self.socket
.send_fds(&[0], &[remote.as_raw_fd()])
.expect("send()");
bincode::serialize_into(&local, task).expect("Task submission failed");
local.shutdown(net::Shutdown::Write).expect("shutdown()");
local
}
pub fn result(socket: &UnixStream) -> Result<TaskOutput> {
bincode::deserialize_from(socket).expect("Failed to read task result")
}
}
|
