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|
mod init;
mod jobserver;
mod ns;
pub mod paths;
mod tar;
mod task;
mod util;
use std::{
fs::File,
net,
os::unix::{net::UnixStream, prelude::*},
slice,
};
use capctl::prctl;
use nix::{
errno::Errno,
sched::CloneFlags,
sys::{signal, signalfd::SignalFd, stat, wait},
unistd::{self, Gid, Pid, Uid},
};
use uds::UnixSeqpacketConn;
use common::{error::*, types::*};
use self::{
jobserver::Jobserver,
util::{clone, unix},
};
#[derive(Debug, Clone)]
pub struct Options {
pub jobs: Option<usize>,
}
fn handle_request(
jobserver: Jobserver,
socket: UnixSeqpacketConn,
request_socket: UnixStream,
) -> (Jobserver, UnixSeqpacketConn) {
let child = |(mut jobserver, socket): (Jobserver, UnixSeqpacketConn)| {
drop(socket);
unsafe { signal::signal(signal::Signal::SIGCHLD, signal::SigHandler::SigDfl) }.unwrap();
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 token = jobserver.wait();
let (pid, mut jobserver) = unsafe {
clone::spawn(None, jobserver, |jobserver| {
let result = task::handle(task, jobserver);
bincode::serialize_into(&request_socket, &result)
.expect("Failed to send task result");
drop(request_socket);
})
}
.expect("fork()");
let wait_res = wait::waitpid(pid, None);
jobserver.post(token);
wait_res.expect("waitpid()");
};
unsafe { clone::spawn(None, (jobserver, socket), child) }
.expect("fork()")
.1
}
fn runner_loop(mut socket: UnixSeqpacketConn, options: &Options) {
let jobs = options
.jobs
.unwrap_or_else(|| unix::nproc().expect("Failed to get number of available CPUs"));
let mut jobserver = Jobserver::new(jobs).expect("Failed to initialize jobserver pipe");
let mut fd = 0;
while let Ok((1, _, n_fd)) = socket.recv_fds(&mut [0], slice::from_mut(&mut fd)) {
assert!(n_fd == 1);
let request_socket = unsafe { UnixStream::from_raw_fd(fd) };
let ret = handle_request(jobserver, socket, request_socket);
jobserver = ret.0;
socket = ret.1;
}
}
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 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 msg_handler = unsafe {
clone::spawn(None, (), |()| {
signal::signal(signal::Signal::SIGCHLD, signal::SigHandler::SigIgn).unwrap();
runner_loop(socket, options);
})
}
.expect("fork()")
.0;
loop {
let _signal = sfd.read_signal().expect("read_signal()").unwrap();
loop {
let status = match wait::waitpid(Pid::from_raw(-1), Some(wait::WaitPidFlag::WNOHANG)) {
Ok(wait::WaitStatus::StillAlive) | Err(Errno::ECHILD) => break,
res => res.expect("waitpid()"),
};
let pid = status.pid().unwrap();
if pid == msg_handler {
return;
}
}
}
}
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()");
let (local, _remote) = clone::spawn(
Some(CloneFlags::CLONE_NEWUSER | CloneFlags::CLONE_NEWNS | CloneFlags::CLONE_NEWPID),
(local, remote),
|(local, remote)| {
drop(local);
runner(uid, gid, remote, lockfile, options);
},
)
.expect("clone()")
.1;
Ok(Runner { socket: local })
}
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")
}
}
|
