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use std::{
convert::{TryFrom, TryInto},
fmt,
io::Cursor,
};
#[cfg(unix)]
use std::{
os::unix::io::{AsRawFd, RawFd},
sync::{Arc, RwLock},
};
use static_assertions::assert_impl_all;
use zbus_names::{BusName, ErrorName, InterfaceName, MemberName, UniqueName};
#[cfg(unix)]
use crate::OwnedFd;
use crate::{
utils::padding_for_8_bytes,
zvariant::{DynamicType, EncodingContext, ObjectPath, Signature, Type},
EndianSig, Error, MessageBuilder, MessageField, MessageFieldCode, MessageFields, MessageHeader,
MessagePrimaryHeader, MessageType, QuickMessageFields, Result, MIN_MESSAGE_SIZE,
NATIVE_ENDIAN_SIG,
};
#[cfg(unix)]
const LOCK_PANIC_MSG: &str = "lock poisoned";
macro_rules! dbus_context {
($n_bytes_before: expr) => {
EncodingContext::<byteorder::NativeEndian>::new_dbus($n_bytes_before)
};
}
#[cfg(unix)]
#[derive(Debug, Eq, PartialEq)]
pub(crate) enum Fds {
Owned(Vec<OwnedFd>),
Raw(Vec<RawFd>),
}
/// A position in the stream of [`Message`] objects received by a single [`zbus::Connection`].
///
/// Note: the relative ordering of values obtained from distinct [`zbus::Connection`] objects is
/// not specified; only sequence numbers originating from the same connection should be compared.
#[derive(Debug, Default, Copy, Clone, Ord, PartialOrd, Eq, PartialEq, Hash)]
pub struct MessageSequence {
recv_seq: u64,
}
impl MessageSequence {
/// A sequence number that is higher than any other; used by errors that terminate a stream.
pub(crate) const LAST: Self = Self { recv_seq: u64::MAX };
}
/// A D-Bus Message.
///
/// The content of the message are stored in serialized format. To deserialize the body of the
/// message, use the [`body`] method. You may also access the header and other details with the
/// various other getters.
///
/// Also provided are constructors for messages of different types. These will mainly be useful for
/// very advanced use cases as typically you will want to create a message for immediate dispatch
/// and hence use the API provided by [`Connection`], even when using the low-level API.
///
/// **Note**: The message owns the received FDs and will close them when dropped. You can call
/// [`take_fds`] after deserializing to `RawFD` using [`body`] if you want to take the ownership.
///
/// [`body`]: #method.body
/// [`take_fds`]: #method.take_fds
/// [`Connection`]: struct.Connection#method.call_method
#[derive(Clone)]
pub struct Message {
pub(crate) primary_header: MessagePrimaryHeader,
pub(crate) quick_fields: QuickMessageFields,
pub(crate) bytes: Vec<u8>,
pub(crate) body_offset: usize,
#[cfg(unix)]
pub(crate) fds: Arc<RwLock<Fds>>,
pub(crate) recv_seq: MessageSequence,
}
assert_impl_all!(Message: Send, Sync, Unpin);
// TODO: Handle non-native byte order: https://github.com/dbus2/zbus/issues/19
impl Message {
/// Create a message of type [`MessageType::MethodCall`].
///
/// [`MessageType::MethodCall`]: enum.MessageType.html#variant.MethodCall
pub fn method<'s, 'd, 'p, 'i, 'm, S, D, P, I, M, B>(
sender: Option<S>,
destination: Option<D>,
path: P,
iface: Option<I>,
method_name: M,
body: &B,
) -> Result<Self>
where
S: TryInto<UniqueName<'s>>,
D: TryInto<BusName<'d>>,
P: TryInto<ObjectPath<'p>>,
I: TryInto<InterfaceName<'i>>,
M: TryInto<MemberName<'m>>,
S::Error: Into<Error>,
D::Error: Into<Error>,
P::Error: Into<Error>,
I::Error: Into<Error>,
M::Error: Into<Error>,
B: serde::ser::Serialize + DynamicType,
{
let mut b = MessageBuilder::method_call(path, method_name)?;
if let Some(sender) = sender {
b = b.sender(sender)?;
}
if let Some(destination) = destination {
b = b.destination(destination)?;
}
if let Some(iface) = iface {
b = b.interface(iface)?;
}
b.build(body)
}
/// Create a message of type [`MessageType::Signal`].
///
/// [`MessageType::Signal`]: enum.MessageType.html#variant.Signal
pub fn signal<'s, 'd, 'p, 'i, 'm, S, D, P, I, M, B>(
sender: Option<S>,
destination: Option<D>,
path: P,
iface: I,
signal_name: M,
body: &B,
) -> Result<Self>
where
S: TryInto<UniqueName<'s>>,
D: TryInto<BusName<'d>>,
P: TryInto<ObjectPath<'p>>,
I: TryInto<InterfaceName<'i>>,
M: TryInto<MemberName<'m>>,
S::Error: Into<Error>,
D::Error: Into<Error>,
P::Error: Into<Error>,
I::Error: Into<Error>,
M::Error: Into<Error>,
B: serde::ser::Serialize + DynamicType,
{
let mut b = MessageBuilder::signal(path, iface, signal_name)?;
if let Some(sender) = sender {
b = b.sender(sender)?;
}
if let Some(destination) = destination {
b = b.destination(destination)?;
}
b.build(body)
}
/// Create a message of type [`MessageType::MethodReturn`].
///
/// [`MessageType::MethodReturn`]: enum.MessageType.html#variant.MethodReturn
pub fn method_reply<'s, S, B>(sender: Option<S>, call: &Self, body: &B) -> Result<Self>
where
S: TryInto<UniqueName<'s>>,
S::Error: Into<Error>,
B: serde::ser::Serialize + DynamicType,
{
let mut b = MessageBuilder::method_return(&call.header()?)?;
if let Some(sender) = sender {
b = b.sender(sender)?;
}
b.build(body)
}
/// Create a message of type [`MessageType::MethodError`].
///
/// [`MessageType::MethodError`]: enum.MessageType.html#variant.MethodError
pub fn method_error<'s, 'e, S, E, B>(
sender: Option<S>,
call: &Self,
name: E,
body: &B,
) -> Result<Self>
where
S: TryInto<UniqueName<'s>>,
S::Error: Into<Error>,
E: TryInto<ErrorName<'e>>,
E::Error: Into<Error>,
B: serde::ser::Serialize + DynamicType,
{
let mut b = MessageBuilder::error(&call.header()?, name)?;
if let Some(sender) = sender {
b = b.sender(sender)?;
}
b.build(body)
}
/// Create a message from bytes.
///
/// The `fds` parameter is only available on unix. It specifies the file descriptors that
/// accompany the message. On the wire, values of the UNIX_FD types store the index of the
/// corresponding file descriptor in this vector. Passing an empty vector on a message that
/// has UNIX_FD will result in an error.
///
/// **Note:** Since the constructed message is not construct by zbus, the receive sequence,
/// which can be acquired from [`Message::recv_position`], is not applicable and hence set
/// to `0`.
///
/// # Safety
///
/// This method is unsafe as bytes may have an invalid encoding.
pub unsafe fn from_bytes(bytes: Vec<u8>, #[cfg(unix)] fds: Vec<OwnedFd>) -> Result<Self> {
Self::from_raw_parts(
bytes,
#[cfg(unix)]
fds,
0,
)
}
/// Create a message from its full contents
pub(crate) fn from_raw_parts(
bytes: Vec<u8>,
#[cfg(unix)] fds: Vec<OwnedFd>,
recv_seq: u64,
) -> Result<Self> {
if EndianSig::try_from(bytes[0])? != NATIVE_ENDIAN_SIG {
return Err(Error::IncorrectEndian);
}
let (primary_header, fields_len) = MessagePrimaryHeader::read(&bytes)?;
let header = zvariant::from_slice(&bytes, dbus_context!(0))?;
#[cfg(unix)]
let fds = Arc::new(RwLock::new(Fds::Owned(fds)));
let header_len = MIN_MESSAGE_SIZE + fields_len as usize;
let body_offset = header_len + padding_for_8_bytes(header_len);
let quick_fields = QuickMessageFields::new(&bytes, &header)?;
Ok(Self {
primary_header,
quick_fields,
bytes,
body_offset,
#[cfg(unix)]
fds,
recv_seq: MessageSequence { recv_seq },
})
}
/// Take ownership of the associated file descriptors in the message.
///
/// When a message is received over a AF_UNIX socket, it may contain associated FDs. To prevent
/// the message from closing those FDs on drop, call this method that returns all the received
/// FDs with their ownership.
///
/// This function is Unix-specific.
///
/// Note: the message will continue to reference the files, so you must keep them open for as
/// long as the message itself.
#[cfg(unix)]
pub fn take_fds(&self) -> Vec<OwnedFd> {
let mut fds_lock = self.fds.write().expect(LOCK_PANIC_MSG);
if let Fds::Owned(ref mut fds) = *fds_lock {
// From now on, it's the caller responsibility to close the fds
let fds = std::mem::take(&mut *fds);
*fds_lock = Fds::Raw(fds.iter().map(|fd| fd.as_raw_fd()).collect());
fds
} else {
vec![]
}
}
/// The signature of the body.
///
/// **Note:** While zbus treats multiple arguments as a struct (to allow you to use the tuple
/// syntax), D-Bus does not. Since this method gives you the signature expected on the wire by
/// D-Bus, the trailing and leading STRUCT signature parenthesis will not be present in case of
/// multiple arguments.
pub fn body_signature(&self) -> Result<Signature<'_>> {
match self
.header()?
.into_fields()
.into_field(MessageFieldCode::Signature)
.ok_or(Error::NoBodySignature)?
{
MessageField::Signature(signature) => Ok(signature),
_ => Err(Error::InvalidField),
}
}
pub fn primary_header(&self) -> &MessagePrimaryHeader {
&self.primary_header
}
pub(crate) fn modify_primary_header<F>(&mut self, mut modifier: F) -> Result<()>
where
F: FnMut(&mut MessagePrimaryHeader) -> Result<()>,
{
modifier(&mut self.primary_header)?;
let mut cursor = Cursor::new(&mut self.bytes);
zvariant::to_writer(&mut cursor, dbus_context!(0), &self.primary_header)
.map(|_| ())
.map_err(Error::from)
}
/// Deserialize the header.
///
/// Note: prefer using the direct access methods if possible; they are more efficient.
pub fn header(&self) -> Result<MessageHeader<'_>> {
zvariant::from_slice(&self.bytes, dbus_context!(0)).map_err(Error::from)
}
/// Deserialize the fields.
///
/// Note: prefer using the direct access methods if possible; they are more efficient.
pub fn fields(&self) -> Result<MessageFields<'_>> {
let ctxt = dbus_context!(crate::PRIMARY_HEADER_SIZE);
zvariant::from_slice(&self.bytes[crate::PRIMARY_HEADER_SIZE..], ctxt).map_err(Error::from)
}
/// The message type.
pub fn message_type(&self) -> MessageType {
self.primary_header.msg_type()
}
/// The object to send a call to, or the object a signal is emitted from.
pub fn path(&self) -> Option<ObjectPath<'_>> {
self.quick_fields.path(self)
}
/// The interface to invoke a method call on, or that a signal is emitted from.
pub fn interface(&self) -> Option<InterfaceName<'_>> {
self.quick_fields.interface(self)
}
/// The member, either the method name or signal name.
pub fn member(&self) -> Option<MemberName<'_>> {
self.quick_fields.member(self)
}
/// The serial number of the message this message is a reply to.
pub fn reply_serial(&self) -> Option<u32> {
self.quick_fields.reply_serial()
}
/// Deserialize the body (without checking signature matching).
pub fn body_unchecked<'d, 'm: 'd, B>(&'m self) -> Result<B>
where
B: serde::de::Deserialize<'d> + Type,
{
{
#[cfg(unix)]
{
zvariant::from_slice_fds(
&self.bytes[self.body_offset..],
Some(&self.fds()),
dbus_context!(0),
)
}
#[cfg(not(unix))]
{
zvariant::from_slice(&self.bytes[self.body_offset..], dbus_context!(0))
}
}
.map_err(Error::from)
}
/// Deserialize the body using the contained signature.
///
/// # Example
///
/// ```
/// # use zbus::Message;
/// # (|| -> zbus::Result<()> {
/// let send_body = (7i32, (2i32, "foo"), vec!["bar"]);
/// let message = Message::method(None::<&str>, Some("zbus.test"), "/", Some("zbus.test"), "ping", &send_body)?;
/// let body : zbus::zvariant::Structure = message.body()?;
/// let fields = body.fields();
/// assert!(matches!(fields[0], zvariant::Value::I32(7)));
/// assert!(matches!(fields[1], zvariant::Value::Structure(_)));
/// assert!(matches!(fields[2], zvariant::Value::Array(_)));
///
/// let reply_msg = Message::method_reply(None::<&str>, &message, &body)?;
/// let reply_value : (i32, (i32, &str), Vec<String>) = reply_msg.body()?;
///
/// assert_eq!(reply_value.0, 7);
/// assert_eq!(reply_value.2.len(), 1);
/// # Ok(()) })().unwrap()
/// ```
pub fn body<'d, 'm: 'd, B>(&'m self) -> Result<B>
where
B: zvariant::DynamicDeserialize<'d>,
{
let body_sig = match self.body_signature() {
Ok(sig) => sig,
Err(Error::NoBodySignature) => Signature::from_static_str_unchecked(""),
Err(e) => return Err(e),
};
{
#[cfg(unix)]
{
zvariant::from_slice_fds_for_dynamic_signature(
&self.bytes[self.body_offset..],
Some(&self.fds()),
dbus_context!(0),
&body_sig,
)
}
#[cfg(not(unix))]
{
zvariant::from_slice_for_dynamic_signature(
&self.bytes[self.body_offset..],
dbus_context!(0),
&body_sig,
)
}
}
.map_err(Error::from)
}
#[cfg(unix)]
pub(crate) fn fds(&self) -> Vec<RawFd> {
match &*self.fds.read().expect(LOCK_PANIC_MSG) {
Fds::Raw(fds) => fds.clone(),
Fds::Owned(fds) => fds.iter().map(|f| f.as_raw_fd()).collect(),
}
}
/// Get a reference to the byte encoding of the message.
pub fn as_bytes(&self) -> &[u8] {
&self.bytes
}
/// Get a reference to the byte encoding of the body of the message.
pub fn body_as_bytes(&self) -> Result<&[u8]> {
Ok(&self.bytes[self.body_offset..])
}
/// Get the receive ordering of a message.
///
/// This may be used to identify how two events were ordered on the bus. It only produces a
/// useful ordering for messages that were produced by the same [`zbus::Connection`].
///
/// This is completely unrelated to the serial number on the message, which is set by the peer
/// and might not be ordered at all.
pub fn recv_position(&self) -> MessageSequence {
self.recv_seq
}
}
impl fmt::Debug for Message {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
let mut msg = f.debug_struct("Msg");
let _ = self.header().map(|h| {
if let Ok(t) = h.message_type() {
msg.field("type", &t);
}
if let Ok(Some(sender)) = h.sender() {
msg.field("sender", &sender);
}
if let Ok(Some(serial)) = h.reply_serial() {
msg.field("reply-serial", &serial);
}
if let Ok(Some(path)) = h.path() {
msg.field("path", &path);
}
if let Ok(Some(iface)) = h.interface() {
msg.field("iface", &iface);
}
if let Ok(Some(member)) = h.member() {
msg.field("member", &member);
}
});
if let Ok(s) = self.body_signature() {
msg.field("body", &s);
}
#[cfg(unix)]
{
let fds = self.fds();
if !fds.is_empty() {
msg.field("fds", &fds);
}
}
msg.finish()
}
}
impl fmt::Display for Message {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
let header = self.header();
let (ty, error_name, sender, member) = if let Ok(h) = header.as_ref() {
(
h.message_type().ok(),
h.error_name().ok().flatten(),
h.sender().ok().flatten(),
h.member().ok().flatten(),
)
} else {
(None, None, None, None)
};
match ty {
Some(MessageType::MethodCall) => {
write!(f, "Method call")?;
if let Some(m) = member {
write!(f, " {m}")?;
}
}
Some(MessageType::MethodReturn) => {
write!(f, "Method return")?;
}
Some(MessageType::Error) => {
write!(f, "Error")?;
if let Some(e) = error_name {
write!(f, " {e}")?;
}
let msg = self.body_unchecked::<&str>();
if let Ok(msg) = msg {
write!(f, ": {msg}")?;
}
}
Some(MessageType::Signal) => {
write!(f, "Signal")?;
if let Some(m) = member {
write!(f, " {m}")?;
}
}
_ => {
write!(f, "Unknown message")?;
}
}
if let Some(s) = sender {
write!(f, " from {s}")?;
}
Ok(())
}
}
#[cfg(test)]
mod tests {
#[cfg(unix)]
use std::os::unix::io::AsRawFd;
use test_log::test;
#[cfg(unix)]
use zvariant::Fd;
#[cfg(unix)]
use super::Fds;
use super::Message;
use crate::Error;
#[test]
fn test() {
#[cfg(unix)]
let stdout = std::io::stdout();
let m = Message::method(
Some(":1.72"),
None::<()>,
"/",
None::<()>,
"do",
&(
#[cfg(unix)]
Fd::from(&stdout),
"foo",
),
)
.unwrap();
assert_eq!(
m.body_signature().unwrap().to_string(),
if cfg!(unix) { "hs" } else { "s" }
);
#[cfg(unix)]
assert_eq!(*m.fds.read().unwrap(), Fds::Raw(vec![stdout.as_raw_fd()]));
let body: Result<u32, Error> = m.body();
assert!(matches!(
body.unwrap_err(),
Error::Variant(zvariant::Error::SignatureMismatch { .. })
));
assert_eq!(m.to_string(), "Method call do from :1.72");
let r = Message::method_reply(None::<()>, &m, &("all fine!")).unwrap();
assert_eq!(r.to_string(), "Method return");
let e = Message::method_error(
None::<()>,
&m,
"org.freedesktop.zbus.Error",
&("kaboom!", 32),
)
.unwrap();
assert_eq!(e.to_string(), "Error org.freedesktop.zbus.Error: kaboom!");
}
}