🛂 Drop support for DBUS_COOKIE_SHA1 auth mechanism

This is in preparation for zbus dropping it in 5.0:

dbus2/zbus#1039

Besides, I added this support mainly for hopes of possibly using it for
a remote transport. However, due to lack of time and funding, I decided
to drop those plans from the roadmap.

src/bin/busd.rs

@@ -49,9 +49,6 @@ enum AuthMechanism {
     /// transferred out-of-band, in particular Unix platforms that can perform credentials-passing
     /// over UNIX domain sockets.
     External,
-    /// This mechanism is designed to establish that a client has the ability to read a private
-    /// file owned by the user being authenticated.
-    Cookie,
     /// Does not perform any authentication at all (not recommended).
     Anonymous,
 }
@@ -60,7 +57,6 @@ impl From<AuthMechanism> for zbus::AuthMechanism {
     fn from(auth_mechanism: AuthMechanism) -> Self {
         match auth_mechanism {
             AuthMechanism::External => zbus::AuthMechanism::External,
-            AuthMechanism::Cookie => zbus::AuthMechanism::Cookie,
             AuthMechanism::Anonymous => zbus::AuthMechanism::Anonymous,
         }
     }

src/bus/mod.rs

@@ -1,16 +1,10 @@
-mod cookies;
-
-use anyhow::{bail, Error, Ok, Result};
-use futures_util::{
-    future::{select, Either},
-    pin_mut,
-};
+use anyhow::{bail, Ok, Result};
 #[cfg(unix)]
 use std::{env, path::Path};
 use std::{str::FromStr, sync::Arc};
 #[cfg(unix)]
 use tokio::fs::remove_file;
-use tokio::{spawn, task::JoinHandle};
+use tokio::spawn;
 use tracing::{debug, info, trace, warn};
 #[cfg(unix)]
 use zbus::address::transport::{Unix, UnixSocket};
@@ -30,7 +24,6 @@ use crate::{
 pub struct Bus {
     inner: Inner,
     listener: Listener,
-    cookie_task: Option<JoinHandle<Error>>,
 }
 
 // All (cheaply) cloneable fields of `Bus` go here.
@@ -99,18 +92,8 @@ impl Bus {
         peers.add_us(peer_conn).await;
         trace!("Self-dial connection created.");
 
-        let cookie_task = if auth_mechanism == AuthMechanism::Cookie {
-            let (cookie_task, cookie_sync_rx) = cookies::run_sync();
-            cookie_sync_rx.await?;
-
-            Some(cookie_task)
-        } else {
-            None
-        };
-
         Ok(Self {
             listener,
-            cookie_task,
             inner: Inner {
                 address,
                 peers,
@@ -201,21 +184,7 @@ impl Bus {
     }
 
     async fn accept_next(&mut self) -> Result<()> {
-        let task = self.cookie_task.take();
-
-        let (socket, task) = match task {
-            Some(task) => {
-                let accept_fut = self.accept();
-                pin_mut!(accept_fut);
-
-                match select(accept_fut, task).await {
-                    Either::Left((socket, task)) => (socket?, Some(task)),
-                    Either::Right((e, _)) => return Err(e?),
-                }
-            }
-            None => (self.accept().await?, None),
-        };
-        self.cookie_task = task;
+        let socket = self.accept().await?;
 
         let id = self.next_id();
         let inner = self.inner.clone();

tests/fdo.rs

@@ -35,7 +35,6 @@ async fn name_ownership_changes() {
 
     // TCP socket
     let address = "tcp:host=127.0.0.1,port=4242".to_string();
-    name_ownership_changes_(&address, AuthMechanism::Cookie).await;
     name_ownership_changes_(&address, AuthMechanism::Anonymous).await;
 }
 

tests/greet.rs

@@ -38,7 +38,6 @@ async fn greet() {
 
     // TCP socket
     let address = "tcp:host=127.0.0.1,port=4248".to_string();
-    greet_(&address, AuthMechanism::Cookie).await;
     greet_(&address, AuthMechanism::Anonymous).await;
 }