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cargo-credential: reset stdin & stdout to the Console
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arlosi committed Aug 9, 2023
1 parent 2b3554f commit 22ae4aa
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Showing 8 changed files with 224 additions and 33 deletions.
4 changes: 3 additions & 1 deletion Cargo.lock

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2 changes: 1 addition & 1 deletion Cargo.toml
Original file line number Diff line number Diff line change
Expand Up @@ -19,7 +19,7 @@ anyhow = "1.0.72"
base64 = "0.21.2"
bytesize = "1.2"
cargo = { path = "" }
cargo-credential = { version = "0.3.0", path = "credential/cargo-credential" }
cargo-credential = { version = "0.4.0", path = "credential/cargo-credential" }
cargo-credential-1password = { version = "0.3.0", path = "credential/cargo-credential-1password" }
cargo-credential-wincred = { version = "0.3.0", path = "credential/cargo-credential-wincred" }
cargo-credential-macos-keychain = { version = "0.3.0", path = "credential/cargo-credential-macos-keychain" }
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7 changes: 1 addition & 6 deletions credential/cargo-credential-1password/src/lib.rs
Original file line number Diff line number Diff line change
Expand Up @@ -80,7 +80,6 @@ impl OnePasswordKeychain {
let mut cmd = Command::new("op");
cmd.args(["signin", "--raw"]);
cmd.stdout(Stdio::piped());
cmd.stdin(cargo_credential::tty().map_err(Box::new)?);
let mut child = cmd
.spawn()
.map_err(|e| format!("failed to spawn `op`: {}", e))?;
Expand Down Expand Up @@ -210,7 +209,7 @@ impl OnePasswordKeychain {
Some(name) => format!("Cargo registry token for {}", name),
None => "Cargo registry token".to_string(),
};
let mut cmd = self.make_cmd(
let cmd = self.make_cmd(
session,
&[
"item",
Expand All @@ -225,10 +224,6 @@ impl OnePasswordKeychain {
CARGO_TAG,
],
);
// For unknown reasons, `op item create` seems to not be happy if
// stdin is not a tty. Otherwise it returns with a 0 exit code without
// doing anything.
cmd.stdin(cargo_credential::tty().map_err(Box::new)?);
self.run_cmd(cmd)?;
Ok(())
}
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4 changes: 3 additions & 1 deletion credential/cargo-credential/Cargo.toml
Original file line number Diff line number Diff line change
@@ -1,17 +1,19 @@
[package]
name = "cargo-credential"
version = "0.3.0"
version = "0.4.0"
edition.workspace = true
license.workspace = true
repository = "https://github.com/rust-lang/cargo"
description = "A library to assist writing Cargo credential helpers."

[dependencies]
anyhow.workspace = true
libc.workspace = true
serde = { workspace = true, features = ["derive"] }
serde_json.workspace = true
thiserror.workspace = true
time.workspace = true
windows-sys = { workspace = true, features = ["Win32_System_Console", "Win32_Foundation"] }

[dev-dependencies]
snapbox = { workspace = true, features = ["examples"] }
25 changes: 25 additions & 0 deletions credential/cargo-credential/examples/stdout-redirected.rs
Original file line number Diff line number Diff line change
@@ -0,0 +1,25 @@
//! Provider used for testing redirection of stdout.
use cargo_credential::{Action, Credential, CredentialResponse, Error, RegistryInfo};

struct MyCredential;

impl Credential for MyCredential {
fn perform(
&self,
_registry: &RegistryInfo,
_action: &Action,
_args: &[&str],
) -> Result<CredentialResponse, Error> {
// Informational messages should be sent on stderr.
eprintln!("message on stderr should be sent the the parent process");

// Reading from stdin and writing to stdout will go to the attached console (tty).
println!("message from test credential provider");
Err(Error::OperationNotSupported)
}
}

fn main() {
cargo_credential::main(MyCredential);
}
35 changes: 11 additions & 24 deletions credential/cargo-credential/src/lib.rs
Original file line number Diff line number Diff line change
Expand Up @@ -38,17 +38,16 @@
//! ```
use serde::{Deserialize, Serialize};
use std::{
fmt::Display,
fs::File,
io::{self, BufRead, BufReader},
};
use std::{fmt::Display, io};
use time::OffsetDateTime;

mod error;
mod secret;
mod stdio;

pub use error::Error;
pub use secret::Secret;
use stdio::stdin_stdout_to_console;

/// Message sent by the credential helper on startup
#[derive(Serialize, Deserialize, Clone, Debug)]
Expand Down Expand Up @@ -241,32 +240,20 @@ fn doit(
if request.v != PROTOCOL_VERSION_1 {
return Err(format!("unsupported protocol version {}", request.v).into());
}
serde_json::to_writer(
std::io::stdout(),
&credential.perform(&request.registry, &request.action, &request.args),
)?;

let response = stdin_stdout_to_console(|| {
credential.perform(&request.registry, &request.action, &request.args)
})?;

serde_json::to_writer(std::io::stdout(), &response)?;
println!();
}
}

/// Open stdin from the tty
pub fn tty() -> Result<File, io::Error> {
#[cfg(unix)]
const IN_DEVICE: &str = "/dev/tty";
#[cfg(windows)]
const IN_DEVICE: &str = "CONIN$";
let stdin = std::fs::OpenOptions::new()
.read(true)
.write(true)
.open(IN_DEVICE)?;
Ok(stdin)
}

/// Read a line of text from stdin.
pub fn read_line() -> Result<String, io::Error> {
let mut reader = BufReader::new(tty()?);
let mut buf = String::new();
reader.read_line(&mut buf)?;
io::stdin().read_line(&mut buf)?;
Ok(buf.trim().to_string())
}

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163 changes: 163 additions & 0 deletions credential/cargo-credential/src/stdio.rs
Original file line number Diff line number Diff line change
@@ -0,0 +1,163 @@
use std::{fs::File, io::Error};

/// Reset stdin and stdout to the attached console / tty for the duration of the closure.
/// If no console is available, stdin and stdout will be redirected to null.
pub fn stdin_stdout_to_console<F, T>(f: F) -> Result<T, Error>
where
F: FnOnce() -> T,
{
let open_write = |f| std::fs::OpenOptions::new().write(true).open(f);

let mut stdin = File::open(imp::IN_DEVICE).or_else(|_| File::open(imp::NULL_DEVICE))?;
let mut stdout = open_write(imp::OUT_DEVICE).or_else(|_| open_write(imp::NULL_DEVICE))?;

let _stdin_guard = imp::ReplacementGuard::new(Stdio::Stdin, &mut stdin)?;
let _stdout_guard = imp::ReplacementGuard::new(Stdio::Stdout, &mut stdout)?;
Ok(f())
}

enum Stdio {
Stdin,
Stdout,
}

#[cfg(windows)]
mod imp {
use super::Stdio;
use std::{fs::File, io::Error, os::windows::prelude::AsRawHandle};
use windows_sys::Win32::{
Foundation::{HANDLE, INVALID_HANDLE_VALUE},
System::Console::{
GetStdHandle, SetStdHandle, STD_HANDLE, STD_INPUT_HANDLE, STD_OUTPUT_HANDLE,
},
};
pub const OUT_DEVICE: &str = "CONOUT$";
pub const IN_DEVICE: &str = "CONIN$";
pub const NULL_DEVICE: &str = "NUL";

/// Restores previous stdio when dropped.
pub struct ReplacementGuard {
std_handle: STD_HANDLE,
previous: HANDLE,
}

impl ReplacementGuard {
pub(super) fn new(stdio: Stdio, replacement: &mut File) -> Result<ReplacementGuard, Error> {
let std_handle = match stdio {
Stdio::Stdin => STD_INPUT_HANDLE,
Stdio::Stdout => STD_OUTPUT_HANDLE,
};

let previous;
unsafe {
// Make a copy of the current handle
previous = GetStdHandle(std_handle);
if previous == INVALID_HANDLE_VALUE {
return Err(std::io::Error::last_os_error());
}

// Replace stdin with the replacement handle
if SetStdHandle(std_handle, replacement.as_raw_handle() as HANDLE) == 0 {
return Err(std::io::Error::last_os_error());
}
}

Ok(ReplacementGuard {
previous,
std_handle,
})
}
}

impl Drop for ReplacementGuard {
fn drop(&mut self) {
unsafe {
// Put previous handle back in to stdin
SetStdHandle(self.std_handle, self.previous);
}
}
}
}

#[cfg(unix)]
mod imp {
use super::Stdio;
use libc::{close, dup, dup2, STDIN_FILENO, STDOUT_FILENO};
use std::{fs::File, io::Error, os::fd::AsRawFd};
pub const IN_DEVICE: &str = "/dev/tty";
pub const OUT_DEVICE: &str = "/dev/tty";
pub const NULL_DEVICE: &str = "/dev/null";

/// Restores previous stdio when dropped.
pub struct ReplacementGuard {
std_fileno: i32,
previous: i32,
}

impl ReplacementGuard {
pub(super) fn new(stdio: Stdio, replacement: &mut File) -> Result<ReplacementGuard, Error> {
let std_fileno = match stdio {
Stdio::Stdin => STDIN_FILENO,
Stdio::Stdout => STDOUT_FILENO,
};

let previous;
unsafe {
// Duplicate the existing stdin file to a new descriptor
previous = dup(std_fileno);
if previous == -1 {
return Err(std::io::Error::last_os_error());
}
// Replace stdin with the replacement file
if dup2(replacement.as_raw_fd(), std_fileno) == -1 {
return Err(std::io::Error::last_os_error());
}
}

Ok(ReplacementGuard {
previous,
std_fileno,
})
}
}

impl Drop for ReplacementGuard {
fn drop(&mut self) {
unsafe {
// Put previous file back in to stdin
dup2(self.previous, self.std_fileno);
// Close the file descriptor we used as a backup
close(self.previous);
}
}
}
}

#[cfg(test)]
mod test {
use std::fs::OpenOptions;
use std::io::{Seek, Write};

use super::imp::ReplacementGuard;
use super::Stdio;

#[test]
fn stdin() {
let tempdir = snapbox::path::PathFixture::mutable_temp().unwrap();
let file = tempdir.path().unwrap().join("stdin");
let mut file = OpenOptions::new()
.read(true)
.write(true)
.create(true)
.open(file)
.unwrap();

writeln!(&mut file, "hello").unwrap();
file.seek(std::io::SeekFrom::Start(0)).unwrap();
{
let _guard = ReplacementGuard::new(Stdio::Stdin, &mut file).unwrap();
let line = std::io::stdin().lines().next().unwrap().unwrap();
assert_eq!(line, "hello");
}
}
}
17 changes: 17 additions & 0 deletions credential/cargo-credential/tests/examples.rs
Original file line number Diff line number Diff line change
Expand Up @@ -2,6 +2,23 @@ use std::path::Path;

use snapbox::cmd::Command;

#[test]
fn stdout_redirected() {
let bin = snapbox::cmd::compile_example("stdout-redirected", []).unwrap();

let hello = r#"{"v":[1]}"#;
let get_request = r#"{"v": 1, "registry": {"index-url":"sparse+https://test/","name":"alternative"},"kind": "get","operation": "read","args": []}"#;
let err_not_supported = r#"{"Err":{"kind":"operation-not-supported"}}"#;

Command::new(bin)
.stdin(format!("{get_request}\n"))
.arg("--cargo-plugin")
.assert()
.stdout_eq(format!("{hello}\n{err_not_supported}\n"))
.stderr_eq("message on stderr should be sent the the parent process\n")
.success();
}

#[test]
fn file_provider() {
let bin = snapbox::cmd::compile_example("file-provider", []).unwrap();
Expand Down

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