askpass.rs

  1use std::path::{Path, PathBuf};
  2use std::time::Duration;
  3
  4#[cfg(unix)]
  5use anyhow::Context as _;
  6use futures::channel::{mpsc, oneshot};
  7#[cfg(unix)]
  8use futures::{AsyncBufReadExt as _, io::BufReader};
  9#[cfg(unix)]
 10use futures::{AsyncWriteExt as _, FutureExt as _, select_biased};
 11use futures::{SinkExt, StreamExt};
 12use gpui::{AsyncApp, BackgroundExecutor, Task};
 13#[cfg(unix)]
 14use smol::fs;
 15#[cfg(unix)]
 16use smol::net::unix::UnixListener;
 17#[cfg(unix)]
 18use util::{ResultExt as _, fs::make_file_executable, get_shell_safe_zed_path};
 19
 20#[derive(PartialEq, Eq)]
 21pub enum AskPassResult {
 22    CancelledByUser,
 23    Timedout,
 24}
 25
 26pub struct AskPassDelegate {
 27    tx: mpsc::UnboundedSender<(String, oneshot::Sender<String>)>,
 28    _task: Task<()>,
 29}
 30
 31impl AskPassDelegate {
 32    pub fn new(
 33        cx: &mut AsyncApp,
 34        password_prompt: impl Fn(String, oneshot::Sender<String>, &mut AsyncApp) + Send + Sync + 'static,
 35    ) -> Self {
 36        let (tx, mut rx) = mpsc::unbounded::<(String, oneshot::Sender<String>)>();
 37        let task = cx.spawn(async move |cx: &mut AsyncApp| {
 38            while let Some((prompt, channel)) = rx.next().await {
 39                password_prompt(prompt, channel, cx);
 40            }
 41        });
 42        Self { tx, _task: task }
 43    }
 44
 45    pub async fn ask_password(&mut self, prompt: String) -> anyhow::Result<String> {
 46        let (tx, rx) = oneshot::channel();
 47        self.tx.send((prompt, tx)).await?;
 48        Ok(rx.await?)
 49    }
 50}
 51
 52#[cfg(unix)]
 53pub struct AskPassSession {
 54    script_path: PathBuf,
 55    _askpass_task: Task<()>,
 56    askpass_opened_rx: Option<oneshot::Receiver<()>>,
 57    askpass_kill_master_rx: Option<oneshot::Receiver<()>>,
 58}
 59
 60#[cfg(unix)]
 61impl AskPassSession {
 62    /// This will create a new AskPassSession.
 63    /// You must retain this session until the master process exits.
 64    #[must_use]
 65    pub async fn new(
 66        executor: &BackgroundExecutor,
 67        mut delegate: AskPassDelegate,
 68    ) -> anyhow::Result<Self> {
 69        let temp_dir = tempfile::Builder::new().prefix("zed-askpass").tempdir()?;
 70        let askpass_socket = temp_dir.path().join("askpass.sock");
 71        let askpass_script_path = temp_dir.path().join("askpass.sh");
 72        let (askpass_opened_tx, askpass_opened_rx) = oneshot::channel::<()>();
 73        let listener =
 74            UnixListener::bind(&askpass_socket).context("failed to create askpass socket")?;
 75        let zed_path = get_shell_safe_zed_path()?;
 76
 77        let (askpass_kill_master_tx, askpass_kill_master_rx) = oneshot::channel::<()>();
 78        let mut kill_tx = Some(askpass_kill_master_tx);
 79
 80        let askpass_task = executor.spawn(async move {
 81            let mut askpass_opened_tx = Some(askpass_opened_tx);
 82
 83            while let Ok((mut stream, _)) = listener.accept().await {
 84                if let Some(askpass_opened_tx) = askpass_opened_tx.take() {
 85                    askpass_opened_tx.send(()).ok();
 86                }
 87                let mut buffer = Vec::new();
 88                let mut reader = BufReader::new(&mut stream);
 89                if reader.read_until(b'\0', &mut buffer).await.is_err() {
 90                    buffer.clear();
 91                }
 92                let prompt = String::from_utf8_lossy(&buffer);
 93                if let Some(password) = delegate
 94                    .ask_password(prompt.to_string())
 95                    .await
 96                    .context("failed to get askpass password")
 97                    .log_err()
 98                {
 99                    stream.write_all(password.as_bytes()).await.log_err();
100                } else {
101                    if let Some(kill_tx) = kill_tx.take() {
102                        kill_tx.send(()).log_err();
103                    }
104                    // note: we expect the caller to drop this task when it's done.
105                    // We need to keep the stream open until the caller is done to avoid
106                    // spurious errors from ssh.
107                    std::future::pending::<()>().await;
108                    drop(stream);
109                }
110            }
111            drop(temp_dir)
112        });
113
114        // Create an askpass script that communicates back to this process.
115        let askpass_script = format!(
116            "{shebang}\n{print_args} | {zed_exe} --askpass={askpass_socket} 2> /dev/null \n",
117            zed_exe = zed_path,
118            askpass_socket = askpass_socket.display(),
119            print_args = "printf '%s\\0' \"$@\"",
120            shebang = "#!/bin/sh",
121        );
122        fs::write(&askpass_script_path, askpass_script).await?;
123        make_file_executable(&askpass_script_path).await?;
124
125        Ok(Self {
126            script_path: askpass_script_path,
127            _askpass_task: askpass_task,
128            askpass_kill_master_rx: Some(askpass_kill_master_rx),
129            askpass_opened_rx: Some(askpass_opened_rx),
130        })
131    }
132
133    pub fn script_path(&self) -> &Path {
134        &self.script_path
135    }
136
137    // This will run the askpass task forever, resolving as many authentication requests as needed.
138    // The caller is responsible for examining the result of their own commands and cancelling this
139    // future when this is no longer needed. Note that this can only be called once, but due to the
140    // drop order this takes an &mut, so you can `drop()` it after you're done with the master process.
141    pub async fn run(&mut self) -> AskPassResult {
142        let connection_timeout = Duration::from_secs(10);
143        let askpass_opened_rx = self.askpass_opened_rx.take().expect("Only call run once");
144        let askpass_kill_master_rx = self
145            .askpass_kill_master_rx
146            .take()
147            .expect("Only call run once");
148
149        select_biased! {
150            _ = askpass_opened_rx.fuse() => {
151                // Note: this await can only resolve after we are dropped.
152                askpass_kill_master_rx.await.ok();
153                return AskPassResult::CancelledByUser
154            }
155
156            _ = futures::FutureExt::fuse(smol::Timer::after(connection_timeout)) => {
157                return AskPassResult::Timedout
158            }
159        }
160    }
161}
162
163/// The main function for when Zed is running in netcat mode for use in askpass.
164/// Called from both the remote server binary and the zed binary in their respective main functions.
165#[cfg(unix)]
166pub fn main(socket: &str) {
167    use std::io::{self, Read, Write};
168    use std::os::unix::net::UnixStream;
169    use std::process::exit;
170
171    let mut stream = match UnixStream::connect(socket) {
172        Ok(stream) => stream,
173        Err(err) => {
174            eprintln!("Error connecting to socket {}: {}", socket, err);
175            exit(1);
176        }
177    };
178
179    let mut buffer = Vec::new();
180    if let Err(err) = io::stdin().read_to_end(&mut buffer) {
181        eprintln!("Error reading from stdin: {}", err);
182        exit(1);
183    }
184
185    if buffer.last() != Some(&b'\0') {
186        buffer.push(b'\0');
187    }
188
189    if let Err(err) = stream.write_all(&buffer) {
190        eprintln!("Error writing to socket: {}", err);
191        exit(1);
192    }
193
194    let mut response = Vec::new();
195    if let Err(err) = stream.read_to_end(&mut response) {
196        eprintln!("Error reading from socket: {}", err);
197        exit(1);
198    }
199
200    if let Err(err) = io::stdout().write_all(&response) {
201        eprintln!("Error writing to stdout: {}", err);
202        exit(1);
203    }
204}
205#[cfg(not(unix))]
206pub fn main(_socket: &str) {}
207
208#[cfg(not(unix))]
209pub struct AskPassSession {
210    path: PathBuf,
211}
212
213#[cfg(not(unix))]
214impl AskPassSession {
215    pub async fn new(_: &BackgroundExecutor, _: AskPassDelegate) -> anyhow::Result<Self> {
216        Ok(Self {
217            path: PathBuf::new(),
218        })
219    }
220
221    pub fn script_path(&self) -> &Path {
222        &self.path
223    }
224
225    pub async fn run(&mut self) -> AskPassResult {
226        futures::FutureExt::fuse(smol::Timer::after(Duration::from_secs(20))).await;
227        AskPassResult::Timedout
228    }
229}