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wry/src/dbus/incoming.rs
2022-02-28 00:14:11 +01:00

219 lines
8.3 KiB
Rust

use super::{
HDR_DESTINATION, HDR_ERROR_NAME, HDR_INTERFACE, HDR_MEMBER, HDR_PATH, HDR_REPLY_SERIAL,
HDR_SENDER, HDR_SIGNATURE, HDR_UNIX_FDS,
};
use crate::dbus::{
CallError, DbusError, DbusSocket, Headers, Parser, MSG_ERROR, MSG_METHOD_RETURN,
};
use crate::utils::ptr_ext::{MutPtrExt, PtrExt};
use crate::ErrorFmt;
use std::cell::UnsafeCell;
use std::collections::VecDeque;
use std::mem::MaybeUninit;
use std::ops::Deref;
use std::rc::Rc;
use uapi::{c, Errno, MaybeUninitSliceExt, MsghdrMut, OwnedFd};
pub async fn handle_incoming(socket: Rc<DbusSocket>) {
let mut incoming = Incoming {
socket,
buf: Box::new([MaybeUninit::uninit(); 4096]),
buf_start: 0,
buf_end: 0,
fds: Default::default(),
cmsg: Box::new([MaybeUninit::uninit(); 256]),
};
incoming.run().await;
}
pub struct Incoming {
socket: Rc<DbusSocket>,
buf: Box<[MaybeUninit<u8>; 4096]>,
buf_start: usize,
buf_end: usize,
fds: VecDeque<Rc<OwnedFd>>,
cmsg: Box<[MaybeUninit<u8>; 256]>,
}
impl Incoming {
async fn run(&mut self) {
loop {
if self.socket.dead.get() {
return;
}
if let Err(e) = self.handle_msg().await {
log::error!(
"{}: Could not process an incoming message: {}",
self.socket.bus_name,
ErrorFmt(e)
);
self.socket.kill();
return;
}
}
}
async fn handle_msg(&mut self) -> Result<(), DbusError> {
let msg_buf_data = UnsafeCell::new(self.socket.bufs.pop().unwrap_or_default());
let msg_buf = unsafe { msg_buf_data.get().deref_mut() };
msg_buf.clear();
const FIXED_HEADER_SIZE: usize = 16;
self.fill_msg_buf(FIXED_HEADER_SIZE, msg_buf).await?;
let endianess = msg_buf[0];
if (endianess == b'l') != cfg!(target_endian = "little") {
return Err(DbusError::InvalidEndianess);
}
let msg_ty = msg_buf[1];
let _flags = msg_buf[2];
let protocol = msg_buf[3];
if protocol != 1 {
return Err(DbusError::InvalidProtocol);
}
let mut fields2 = [0u32; 3];
uapi::pod_write(&msg_buf[4..], &mut fields2[..]).unwrap();
let [body_len, _serial, headers_len] = fields2;
let dyn_header_len = headers_len + (headers_len.wrapping_neg() & 7);
let remaining = dyn_header_len + body_len;
self.fill_msg_buf(remaining as usize, msg_buf).await?;
drop(msg_buf);
let msg_buf = unsafe { msg_buf_data.get().deref().deref() };
let headers = &msg_buf[FIXED_HEADER_SIZE..FIXED_HEADER_SIZE + headers_len as usize];
let headers = self.parse_headers(headers)?;
let unix_fds = headers.unix_fds.unwrap_or(0) as usize;
if self.fds.len() < unix_fds {
return Err(DbusError::TooFewFds);
}
let fds: Vec<_> = self.fds.drain(..unix_fds).collect();
let mut parser = Parser {
buf: &msg_buf,
pos: FIXED_HEADER_SIZE + dyn_header_len as usize,
fds: &fds,
};
match msg_ty {
MSG_METHOD_RETURN | MSG_ERROR => {
let serial = match headers.reply_serial {
Some(s) => s,
_ => return Err(DbusError::NoReplySerial),
};
if let Some(reply) = self.socket.reply_handlers.remove(&serial) {
if msg_ty == MSG_ERROR {
let ename = match headers.error_name {
Some(n) => n.into_owned(),
_ => return Err(DbusError::NoErrorName),
};
let mut emsg = None;
if let Some(sig) = headers.signature {
if sig.0.starts_with("s") {
emsg = Some(parser.read_string()?.into_owned());
}
}
let error = CallError {
name: ename,
msg: emsg,
};
reply.handle_error(&self.socket, DbusError::CallError(error));
} else {
let sig = headers.signature.as_deref().unwrap_or("");
if sig != reply.signature() {
log::error!(
"{}: Message reply has an invalid signature: expected: {}, actual: {}",
self.socket.bus_name,
sig,
reply.signature()
);
} else {
let buf = unsafe { std::mem::take(msg_buf_data.get().deref_mut()) };
if let Err(e) = reply.handle(&self.socket, &headers, &mut parser, buf) {
log::error!(
"{}: Could not handle reply: {}",
self.socket.bus_name,
ErrorFmt(e)
);
}
}
}
}
}
_ => {}
}
let msg_buf = msg_buf_data.into_inner();
if msg_buf.capacity() > 0 {
self.socket.bufs.push(msg_buf);
}
Ok(())
}
fn parse_headers<'a>(&self, buf: &'a [u8]) -> Result<Headers<'a>, DbusError> {
let mut parser = Parser::new(buf, &[]);
let mut headers = Headers::default();
while !parser.eof() {
parser.align_to(8)?;
let ty: u8 = parser.read_pod()?;
let val = parser.read_variant()?;
match ty {
HDR_PATH => headers.path = Some(val.into_object_path()?),
HDR_INTERFACE => headers.interface = Some(val.into_string()?),
HDR_MEMBER => headers.member = Some(val.into_string()?),
HDR_ERROR_NAME => headers.error_name = Some(val.into_string()?),
HDR_REPLY_SERIAL => headers.reply_serial = Some(val.into_u32()?),
HDR_DESTINATION => headers.destination = Some(val.into_string()?),
HDR_SENDER => headers.sender = Some(val.into_string()?),
HDR_SIGNATURE => headers.signature = Some(val.into_signature()?),
HDR_UNIX_FDS => headers.unix_fds = Some(val.into_u32()?),
_ => {}
}
}
Ok(headers)
}
async fn fill_msg_buf(&mut self, mut n: usize, buf: &mut Vec<u8>) -> Result<(), DbusError> {
while n > 0 {
if self.buf_start == self.buf_end {
while let Err(e) = self.recvmsg() {
if e.0 != c::EAGAIN {
return Err(DbusError::ReadError(e.into()));
}
let _ = self.socket.fd.readable().await;
}
if self.buf_start == self.buf_end {
return Err(DbusError::Closed);
}
}
let read = n.min(self.buf_end - self.buf_start);
let buf_start = self.buf_start % self.buf.len();
unsafe {
buf.extend_from_slice(
self.buf[buf_start..buf_start + read].slice_assume_init_ref(),
);
}
n -= read;
self.buf_start += read;
}
Ok(())
}
fn recvmsg(&mut self) -> Result<(), Errno> {
self.buf_start = 0;
self.buf_end = 0;
let mut iov = [&mut self.buf[..]];
let mut hdr = MsghdrMut {
iov: &mut iov[..],
control: Some(&mut self.cmsg[..]),
name: uapi::sockaddr_none_mut(),
flags: 0,
};
let (ivec, _, mut cmsg) =
uapi::recvmsg(self.socket.fd.raw(), &mut hdr, c::MSG_CMSG_CLOEXEC)?;
self.buf_end += ivec.len();
while cmsg.len() > 0 {
let (_, hdr, body) = uapi::cmsg_read(&mut cmsg)?;
if hdr.cmsg_level == c::SOL_SOCKET && hdr.cmsg_type == c::SCM_RIGHTS {
for fd in uapi::pod_iter(body)? {
self.fds.push_back(Rc::new(OwnedFd::new(fd)));
}
}
}
Ok(())
}
}