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forker: split worker implementation

This commit is contained in:
kossLAN 2026-05-29 19:31:48 -04:00
parent e78e9bcd4c
commit b0603f0639
No known key found for this signature in database
2 changed files with 322 additions and 299 deletions

View file

@ -1,41 +1,34 @@
mod io;
mod protocol;
mod worker;
use {
crate::{
async_engine::{AsyncEngine, SpawnedFuture},
compositor::{DISPLAY, LIBEI_SOCKET, WAYLAND_DISPLAY},
async_engine::SpawnedFuture,
compositor::LIBEI_SOCKET,
forker::io::{IoIn, IoOut},
forker::protocol::{ForkerMessage, ServerMessage, bincode_ops},
io_uring::IoUring,
forker::protocol::{ForkerMessage, ServerMessage},
forker::worker::Forker,
state::State,
utils::{
buffd::BufFdError,
clone3::{Forked, double_fork, fork_with_pidfd},
clone3::double_fork,
copyhashmap::CopyHashMap,
errorfmt::ErrorFmt,
numcell::NumCell,
oserror::OsErrorExt2,
pipe::{Pipe, pipe},
process_name::set_process_name,
queue::AsyncQueue,
},
xwayland,
},
ahash::AHashMap,
bincode::Options,
log::Level,
std::{
cell::{Cell, RefCell},
env,
ffi::OsStr,
io::{Read, Write},
os::unix::ffi::OsStrExt,
rc::{Rc, Weak},
task::{Poll, Waker},
},
thiserror::Error,
uapi::{Errno, Fd, IntoUstr, OwnedFd, UstrPtr, c},
uapi::{OwnedFd, c},
};
pub struct ForkerProxy {
@ -292,288 +285,3 @@ impl ForkerProxy {
state.forker.set(None);
}
}
struct Forker {
socket: Rc<OwnedFd>,
ae: Rc<AsyncEngine>,
ring: Rc<IoUring>,
fds: RefCell<Vec<Rc<OwnedFd>>>,
outgoing: AsyncQueue<ForkerMessage>,
pending_spawns: CopyHashMap<c::pid_t, SpawnedFuture<()>>,
}
impl Forker {
fn handle(ppid: c::pid_t, socket: OwnedFd) -> ! {
unsafe {
env::set_var("XDG_SESSION_TYPE", "wayland");
env::remove_var(DISPLAY);
env::remove_var(WAYLAND_DISPLAY);
}
set_process_name("the ol' forker");
setup_deathsig(ppid);
unsafe {
c::signal(c::SIGCHLD, c::SIG_IGN);
}
let socket = Rc::new(setup_fds(socket));
std::panic::set_hook({
let socket = socket.raw();
Box::new(move |pi| {
let msg = ForkerMessage::Log {
level: log::Level::Error as _,
msg: format!("The ol' forker panicked: {}", pi),
};
let msg = bincode_ops().serialize(&msg).unwrap();
let _ = Fd::new(socket).write_all(&msg);
})
});
let ae = AsyncEngine::new();
let ring = IoUring::new(&ae, 32).unwrap();
let forker = Rc::new(Forker {
socket,
ae: ae.clone(),
ring: ring.clone(),
fds: RefCell::new(vec![]),
outgoing: Default::default(),
pending_spawns: Default::default(),
});
let _f1 = ae.spawn("forker incoming", forker.clone().incoming());
let _f2 = ae.spawn("forker outgoing", forker.clone().outgoing());
let _ = ring.run();
std::process::exit(1);
}
async fn outgoing(self: Rc<Self>) {
let mut io = IoOut::new(&self.socket, &self.ring);
loop {
let msg = self.outgoing.pop().await;
for fd in self.fds.borrow_mut().drain(..) {
io.push_fd(fd);
}
if io.write_msg(msg).await.is_err() {
self.ring.stop();
return;
}
}
}
async fn incoming(self: Rc<Self>) {
let mut io = IoIn::new(&self.socket, &self.ring);
loop {
let msg = match io.read_msg().await {
Ok(m) => m,
_ => {
self.ring.stop();
return;
}
};
self.handle_msg(msg, &mut io);
}
}
fn handle_msg(self: &Rc<Self>, msg: ServerMessage, io: &mut IoIn) {
match msg {
ServerMessage::SetEnv { var, val } => self.handle_set_env(&var, val),
ServerMessage::Spawn {
prog,
args,
env,
fds,
pidfd_id,
} => self.handle_spawn(prog, args, env, fds, io, pidfd_id),
}
}
fn handle_set_env(self: &Rc<Self>, var: &[u8], val: Option<Vec<u8>>) {
let var = OsStr::from_bytes(var);
unsafe {
match val {
Some(val) => env::set_var(var, OsStr::from_bytes(&val)),
_ => env::remove_var(var),
}
}
}
fn handle_spawn(
self: &Rc<Self>,
prog: String,
args: Vec<String>,
env: Vec<(String, Option<String>)>,
fds: Vec<i32>,
io: &mut IoIn,
pidfd_id: Option<u32>,
) {
let fds = fds
.into_iter()
.map(|a| (a, Rc::try_unwrap(io.pop_fd().unwrap()).unwrap()))
.collect();
self.spawn(prog, args, env, fds, pidfd_id)
}
fn spawn(
self: &Rc<Self>,
prog: String,
args: Vec<String>,
env: Vec<(String, Option<String>)>,
fds: Vec<(i32, OwnedFd)>,
pidfd_id: Option<u32>,
) {
let Pipe { read, mut write } = pipe().unwrap();
let res = match fork_with_pidfd(false) {
Ok(o) => o,
Err(e) => {
self.fail_pidfd(pidfd_id);
self.outgoing.push(ForkerMessage::Log {
level: log::Level::Error as usize,
msg: ErrorFmt(e).to_string(),
});
return;
}
};
match res {
Forked::Parent { pid, pidfd } => {
drop(write);
let slf = self.clone();
let spawn = self.ae.spawn("await spawn", async move {
let read = Rc::new(read);
if let Err(e) = slf.ring.readable(&read).await {
log::error!(
"Cannot wait for the child fd to become readable: {}",
ErrorFmt(e)
);
slf.fail_pidfd(pidfd_id);
} else {
let mut s = String::new();
let _ = Fd::new(read.raw()).read_to_string(&mut s);
if s.len() > 0 {
slf.outgoing.push(ForkerMessage::Log {
level: log::Level::Error as _,
msg: format!("Could not spawn `{}`: {}", prog, s),
});
slf.fail_pidfd(pidfd_id);
} else {
if let Some(id) = pidfd_id {
slf.fds.borrow_mut().push(Rc::new(pidfd));
slf.outgoing.push(ForkerMessage::PidFd {
id,
success: true,
pid,
});
}
}
}
slf.pending_spawns.remove(&pid);
});
self.pending_spawns.set(pid, spawn);
}
Forked::Child { .. } => {
let err: Result<(), SpawnError> = (|| {
if let Some(max_desired) = fds.iter().map(|v| v.0).max() {
write = uapi::fcntl_dupfd_cloexec(write.raw(), max_desired.wrapping_add(1))
.map_os_err(SpawnError::Dupfd)?;
}
let fds = map_fds(fds)?;
for fd in fds {
let fd = fd.unwrap();
let res: Result<_, Errno> = (|| {
uapi::fcntl_setfd(fd, uapi::fcntl_getfd(fd)? & !c::FD_CLOEXEC)?;
Ok(())
})();
res.map_os_err(SpawnError::Cloexec)?;
}
unsafe {
c::signal(c::SIGCHLD, c::SIG_DFL);
}
for (key, val) in env {
unsafe {
match val {
None => env::remove_var(&key),
Some(val) => env::set_var(&key, &val),
}
}
}
let prog = prog.into_ustr();
let mut argsnt = UstrPtr::new();
argsnt.push(&prog);
for arg in args {
argsnt.push(arg);
}
uapi::execvp(&prog, &argsnt).map_os_err(SpawnError::Exec)?;
Ok(())
})();
if let Err(e) = err {
let _ = write.write_all(ErrorFmt(e).to_string().as_bytes());
}
std::process::exit(1);
}
}
}
fn fail_pidfd(&self, pidfd_id: Option<u32>) {
if let Some(id) = pidfd_id {
self.outgoing.push(ForkerMessage::PidFd {
id,
success: false,
pid: 0,
});
}
}
}
#[derive(Debug, Error)]
enum SpawnError {
#[error("exec failed")]
Exec(#[source] crate::utils::oserror::OsError),
#[error("Could not unset cloexec flag")]
Cloexec(#[source] crate::utils::oserror::OsError),
#[error("dupfd faild")]
Dupfd(#[source] crate::utils::oserror::OsError),
}
fn setup_fds(mut socket: OwnedFd) -> OwnedFd {
if socket.raw() != 0 {
uapi::dup3(socket.unwrap(), 0, 0).unwrap();
socket = OwnedFd::new(0);
}
uapi::close_range(1, c::c_uint::MAX, 0).unwrap();
uapi::dup3(socket.raw(), 3, c::O_CLOEXEC).unwrap();
socket = OwnedFd::new(3);
let fd = uapi::open("/dev/null", c::O_RDWR, 0).unwrap().unwrap();
assert!(fd == 0);
uapi::dup2(0, 1).unwrap();
uapi::dup2(0, 2).unwrap();
socket
}
fn setup_deathsig(ppid: c::pid_t) {
unsafe {
let res = c::prctl(c::PR_SET_PDEATHSIG, c::SIGKILL as c::c_ulong);
uapi::map_err!(res).unwrap();
if ppid != uapi::getppid() {
std::process::exit(0);
}
}
}
fn map_fds(fds: Vec<(i32, OwnedFd)>) -> Result<Vec<OwnedFd>, SpawnError> {
let mut desired: Vec<_> = fds.iter().map(|v| v.0).collect();
desired.sort_by(|a, b| b.cmp(a));
let mut existing_to_desired: AHashMap<_, _> = fds.iter().map(|v| (v.1.raw(), v.0)).collect();
let mut desired_to_existing: AHashMap<_, _> = fds.into_iter().map(|v| (v.0, v.1)).collect();
for desired in desired {
let existing = desired_to_existing.get(&desired).unwrap().raw();
if existing == desired {
continue;
}
if let Some(conflict_desired) = existing_to_desired.get(&desired).copied() {
let new = uapi::fcntl_dupfd_cloexec(desired, 0).map_os_err(SpawnError::Dupfd)?;
existing_to_desired.remove(&desired);
existing_to_desired.insert(new.raw(), conflict_desired);
desired_to_existing.insert(conflict_desired, new);
}
uapi::dup3(existing, desired, c::O_CLOEXEC).map_os_err(SpawnError::Dupfd)?;
existing_to_desired.remove(&existing);
existing_to_desired.insert(desired, desired);
desired_to_existing.insert(desired, OwnedFd::new(desired));
}
Ok(desired_to_existing.into_values().collect())
}

315
src/forker/worker.rs Normal file
View file

@ -0,0 +1,315 @@
use {
crate::{
async_engine::{AsyncEngine, SpawnedFuture},
compositor::{DISPLAY, WAYLAND_DISPLAY},
forker::{
io::{IoIn, IoOut},
protocol::{ForkerMessage, ServerMessage, bincode_ops},
},
io_uring::IoUring,
utils::{
clone3::{Forked, fork_with_pidfd},
copyhashmap::CopyHashMap,
errorfmt::ErrorFmt,
oserror::OsErrorExt2,
pipe::{Pipe, pipe},
process_name::set_process_name,
queue::AsyncQueue,
},
},
ahash::AHashMap,
bincode::Options,
std::{
cell::RefCell,
env,
ffi::OsStr,
io::{Read, Write},
os::unix::ffi::OsStrExt,
rc::Rc,
},
thiserror::Error,
uapi::{Errno, Fd, IntoUstr, OwnedFd, UstrPtr, c},
};
pub(super) struct Forker {
socket: Rc<OwnedFd>,
ae: Rc<AsyncEngine>,
ring: Rc<IoUring>,
fds: RefCell<Vec<Rc<OwnedFd>>>,
outgoing: AsyncQueue<ForkerMessage>,
pending_spawns: CopyHashMap<c::pid_t, SpawnedFuture<()>>,
}
impl Forker {
pub(super) fn handle(ppid: c::pid_t, socket: OwnedFd) -> ! {
unsafe {
env::set_var("XDG_SESSION_TYPE", "wayland");
env::remove_var(DISPLAY);
env::remove_var(WAYLAND_DISPLAY);
}
set_process_name("the ol' forker");
setup_deathsig(ppid);
unsafe {
c::signal(c::SIGCHLD, c::SIG_IGN);
}
let socket = Rc::new(setup_fds(socket));
std::panic::set_hook({
let socket = socket.raw();
Box::new(move |pi| {
let msg = ForkerMessage::Log {
level: log::Level::Error as _,
msg: format!("The ol' forker panicked: {}", pi),
};
let msg = bincode_ops().serialize(&msg).unwrap();
let _ = Fd::new(socket).write_all(&msg);
})
});
let ae = AsyncEngine::new();
let ring = IoUring::new(&ae, 32).unwrap();
let forker = Rc::new(Forker {
socket,
ae: ae.clone(),
ring: ring.clone(),
fds: RefCell::new(vec![]),
outgoing: Default::default(),
pending_spawns: Default::default(),
});
let _f1 = ae.spawn("forker incoming", forker.clone().incoming());
let _f2 = ae.spawn("forker outgoing", forker.clone().outgoing());
let _ = ring.run();
std::process::exit(1);
}
async fn outgoing(self: Rc<Self>) {
let mut io = IoOut::new(&self.socket, &self.ring);
loop {
let msg = self.outgoing.pop().await;
for fd in self.fds.borrow_mut().drain(..) {
io.push_fd(fd);
}
if io.write_msg(msg).await.is_err() {
self.ring.stop();
return;
}
}
}
async fn incoming(self: Rc<Self>) {
let mut io = IoIn::new(&self.socket, &self.ring);
loop {
let msg = match io.read_msg().await {
Ok(m) => m,
_ => {
self.ring.stop();
return;
}
};
self.handle_msg(msg, &mut io);
}
}
fn handle_msg(self: &Rc<Self>, msg: ServerMessage, io: &mut IoIn) {
match msg {
ServerMessage::SetEnv { var, val } => self.handle_set_env(&var, val),
ServerMessage::Spawn {
prog,
args,
env,
fds,
pidfd_id,
} => self.handle_spawn(prog, args, env, fds, io, pidfd_id),
}
}
fn handle_set_env(self: &Rc<Self>, var: &[u8], val: Option<Vec<u8>>) {
let var = OsStr::from_bytes(var);
unsafe {
match val {
Some(val) => env::set_var(var, OsStr::from_bytes(&val)),
_ => env::remove_var(var),
}
}
}
fn handle_spawn(
self: &Rc<Self>,
prog: String,
args: Vec<String>,
env: Vec<(String, Option<String>)>,
fds: Vec<i32>,
io: &mut IoIn,
pidfd_id: Option<u32>,
) {
let fds = fds
.into_iter()
.map(|a| (a, Rc::try_unwrap(io.pop_fd().unwrap()).unwrap()))
.collect();
self.spawn(prog, args, env, fds, pidfd_id)
}
fn spawn(
self: &Rc<Self>,
prog: String,
args: Vec<String>,
env: Vec<(String, Option<String>)>,
fds: Vec<(i32, OwnedFd)>,
pidfd_id: Option<u32>,
) {
let Pipe { read, mut write } = pipe().unwrap();
let res = match fork_with_pidfd(false) {
Ok(o) => o,
Err(e) => {
self.fail_pidfd(pidfd_id);
self.outgoing.push(ForkerMessage::Log {
level: log::Level::Error as usize,
msg: ErrorFmt(e).to_string(),
});
return;
}
};
match res {
Forked::Parent { pid, pidfd } => {
drop(write);
let slf = self.clone();
let spawn = self.ae.spawn("await spawn", async move {
let read = Rc::new(read);
if let Err(e) = slf.ring.readable(&read).await {
log::error!(
"Cannot wait for the child fd to become readable: {}",
ErrorFmt(e)
);
slf.fail_pidfd(pidfd_id);
} else {
let mut s = String::new();
let _ = Fd::new(read.raw()).read_to_string(&mut s);
if s.len() > 0 {
slf.outgoing.push(ForkerMessage::Log {
level: log::Level::Error as _,
msg: format!("Could not spawn `{}`: {}", prog, s),
});
slf.fail_pidfd(pidfd_id);
} else if let Some(id) = pidfd_id {
slf.fds.borrow_mut().push(Rc::new(pidfd));
slf.outgoing.push(ForkerMessage::PidFd {
id,
success: true,
pid,
});
}
}
slf.pending_spawns.remove(&pid);
});
self.pending_spawns.set(pid, spawn);
}
Forked::Child { .. } => {
let err: Result<(), SpawnError> = (|| {
if let Some(max_desired) = fds.iter().map(|v| v.0).max() {
write = uapi::fcntl_dupfd_cloexec(write.raw(), max_desired.wrapping_add(1))
.map_os_err(SpawnError::Dupfd)?;
}
let fds = map_fds(fds)?;
for fd in fds {
let fd = fd.unwrap();
let res: Result<_, Errno> = (|| {
uapi::fcntl_setfd(fd, uapi::fcntl_getfd(fd)? & !c::FD_CLOEXEC)?;
Ok(())
})();
res.map_os_err(SpawnError::Cloexec)?;
}
unsafe {
c::signal(c::SIGCHLD, c::SIG_DFL);
}
for (key, val) in env {
unsafe {
match val {
None => env::remove_var(&key),
Some(val) => env::set_var(&key, &val),
}
}
}
let prog = prog.into_ustr();
let mut argsnt = UstrPtr::new();
argsnt.push(&prog);
for arg in args {
argsnt.push(arg);
}
uapi::execvp(&prog, &argsnt).map_os_err(SpawnError::Exec)?;
Ok(())
})();
if let Err(e) = err {
let _ = write.write_all(ErrorFmt(e).to_string().as_bytes());
}
std::process::exit(1);
}
}
}
fn fail_pidfd(&self, pidfd_id: Option<u32>) {
if let Some(id) = pidfd_id {
self.outgoing.push(ForkerMessage::PidFd {
id,
success: false,
pid: 0,
});
}
}
}
#[derive(Debug, Error)]
enum SpawnError {
#[error("exec failed")]
Exec(#[source] crate::utils::oserror::OsError),
#[error("Could not unset cloexec flag")]
Cloexec(#[source] crate::utils::oserror::OsError),
#[error("dupfd faild")]
Dupfd(#[source] crate::utils::oserror::OsError),
}
fn setup_fds(mut socket: OwnedFd) -> OwnedFd {
if socket.raw() != 0 {
uapi::dup3(socket.unwrap(), 0, 0).unwrap();
socket = OwnedFd::new(0);
}
uapi::close_range(1, c::c_uint::MAX, 0).unwrap();
uapi::dup3(socket.raw(), 3, c::O_CLOEXEC).unwrap();
socket = OwnedFd::new(3);
let fd = uapi::open("/dev/null", c::O_RDWR, 0).unwrap().unwrap();
assert!(fd == 0);
uapi::dup2(0, 1).unwrap();
uapi::dup2(0, 2).unwrap();
socket
}
fn setup_deathsig(ppid: c::pid_t) {
unsafe {
let res = c::prctl(c::PR_SET_PDEATHSIG, c::SIGKILL as c::c_ulong);
uapi::map_err!(res).unwrap();
if ppid != uapi::getppid() {
std::process::exit(0);
}
}
}
fn map_fds(fds: Vec<(i32, OwnedFd)>) -> Result<Vec<OwnedFd>, SpawnError> {
let mut desired: Vec<_> = fds.iter().map(|v| v.0).collect();
desired.sort_by(|a, b| b.cmp(a));
let mut existing_to_desired: AHashMap<_, _> = fds.iter().map(|v| (v.1.raw(), v.0)).collect();
let mut desired_to_existing: AHashMap<_, _> = fds.into_iter().map(|v| (v.0, v.1)).collect();
for desired in desired {
let existing = desired_to_existing.get(&desired).unwrap().raw();
if existing == desired {
continue;
}
if let Some(conflict_desired) = existing_to_desired.get(&desired).copied() {
let new = uapi::fcntl_dupfd_cloexec(desired, 0).map_os_err(SpawnError::Dupfd)?;
existing_to_desired.remove(&desired);
existing_to_desired.insert(new.raw(), conflict_desired);
desired_to_existing.insert(conflict_desired, new);
}
uapi::dup3(existing, desired, c::O_CLOEXEC).map_os_err(SpawnError::Dupfd)?;
existing_to_desired.remove(&existing);
existing_to_desired.insert(desired, desired);
desired_to_existing.insert(desired, OwnedFd::new(desired));
}
Ok(desired_to_existing.into_values().collect())
}