From b6ed40dbe857f773eb1084310905fcd249550302 Mon Sep 17 00:00:00 2001
From: Kelvin Ly <kelvin.ly1618@gmail.com>
Date: Wed, 2 Nov 2016 09:26:29 -0400
Subject: [PATCH] Add openpty()

---
 src/lib.rs       |  2 ++
 src/pty.rs       | 52 ++++++++++++++++++++++++++++++++++++++++++++++++
 test/test.rs     |  1 +
 test/test_pty.rs | 36 +++++++++++++++++++++++++++++++++
 4 files changed, 91 insertions(+)
 create mode 100644 src/pty.rs
 create mode 100644 test/test_pty.rs

diff --git a/src/lib.rs b/src/lib.rs
index ecbf139dc6..56ed5c3fa8 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -44,6 +44,8 @@ pub mod mount;
 #[cfg(target_os = "linux")]
 pub mod mqueue;
 
+pub mod pty;
+
 #[cfg(any(target_os = "linux", target_os = "macos"))]
 pub mod poll;
 
diff --git a/src/pty.rs b/src/pty.rs
new file mode 100644
index 0000000000..d07e7684a5
--- /dev/null
+++ b/src/pty.rs
@@ -0,0 +1,52 @@
+use libc;
+
+use {Errno, Result};
+use std::os::unix::io::RawFd;
+
+use sys::termios::Termios;
+
+pub use libc::pid_t as SessionId;
+pub use libc::winsize as Winsize;
+
+pub struct OpenptyResult {
+    pub master: RawFd,
+    pub slave: RawFd,
+}
+
+/// Create a new pseudoterminal, returning the slave and master file descriptors
+/// in `OpenptyResult`
+/// (see [openpty](http://man7.org/linux/man-pages/man3/openpty.3.html)). 
+///
+/// If `winsize` is not `None`, the window size of the slave will be set to
+/// the values in `winsize`. If `termios` is not `None`, the pseudoterminal's
+/// terminal settings of the slave will be set to the values in `termios`.
+#[inline]
+pub fn openpty<'a, 'b, T: Into<Option<&'a Winsize>>, U: Into<Option<&'b Termios>>>(winsize: T, termios: U) -> Result<OpenptyResult> {
+    use std::ptr;
+
+    let mut slave: libc::c_int = -1;
+    let mut master: libc::c_int = -1;
+    let c_termios = match termios.into() {
+        Some(termios) => termios as *const Termios,
+        None => ptr::null() as *const Termios,
+    };
+    let c_winsize = match winsize.into() {
+        Some(ws) => ws as *const Winsize,
+        None => ptr::null() as *const Winsize,
+    };
+    let ret = unsafe {
+        libc::openpty(
+            &mut master as *mut libc::c_int,
+            &mut slave as *mut libc::c_int,
+            ptr::null_mut(),
+            c_termios as *mut libc::termios,
+            c_winsize as *mut Winsize)
+    };
+
+    let _ = try!(Errno::result(ret));
+
+    Ok(OpenptyResult {
+        master: master,
+        slave: slave,
+    })
+}
diff --git a/test/test.rs b/test/test.rs
index 1357642ef6..d73a021882 100644
--- a/test/test.rs
+++ b/test/test.rs
@@ -13,6 +13,7 @@ mod sys;
 mod test_fcntl;
 mod test_net;
 mod test_nix_path;
+mod test_pty;
 #[cfg(any(target_os = "linux", target_os = "android"))]
 mod test_sendfile;
 mod test_stat;
diff --git a/test/test_pty.rs b/test/test_pty.rs
new file mode 100644
index 0000000000..1fcd4a891b
--- /dev/null
+++ b/test/test_pty.rs
@@ -0,0 +1,36 @@
+use nix::pty::openpty;
+use nix::unistd::{read, write, close};
+
+#[test]
+fn test_openpty() {
+    // TODO: figure out the right termios settings to pass in here
+    let pty = openpty(None, None).unwrap();
+    assert!(pty.master > 0); // must be valid file descriptors
+    assert!(pty.slave > 0);
+
+    // writing to one should be readable on the other one
+    let string = "foofoofoo\n";
+    let mut buf = [0u8; 16];
+    write(pty.master, string.as_bytes()).unwrap();
+    let len = read(pty.slave, &mut buf).unwrap();
+
+    assert_eq!(len, string.len());
+    assert_eq!(&buf[0..len], string.as_bytes());
+
+    // read the echo as well
+    let echoed_string = "foofoofoo\r\n";
+    let len = read(pty.master, &mut buf).unwrap();
+    assert_eq!(len, echoed_string.len());
+    assert_eq!(&buf[0..len], echoed_string.as_bytes());
+
+    let string2 = "barbarbarbar\n";
+    let echoed_string2 = "barbarbarbar\r\n";
+    write(pty.slave, string2.as_bytes()).unwrap();
+    let len = read(pty.master, &mut buf).unwrap();
+
+    assert_eq!(len, echoed_string2.len());
+    assert_eq!(&buf[0..len], echoed_string2.as_bytes());
+
+    close(pty.master).unwrap();
+    close(pty.slave).unwrap();
+}