From 286c3d95f514b59b4c14b6e7c2e35632192f0e24 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 1/3] Add openpty()

---
 src/lib.rs       |  2 ++
 src/pty.rs       | 43 +++++++++++++++++++++++++++++++++++++++++++
 test/test.rs     |  1 +
 test/test_pty.rs | 36 ++++++++++++++++++++++++++++++++++++
 4 files changed, 82 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 ab8339efc1..7722a451fc 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -43,6 +43,8 @@ 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..04fd05b1df
--- /dev/null
+++ b/src/pty.rs
@@ -0,0 +1,43 @@
+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,
+}
+
+#[inline]
+pub fn openpty(winsize: Option<Winsize>, termios: Option<Termios>) -> Result<OpenptyResult> {
+    let mut slave: libc::c_int = -1;
+    let mut master: libc::c_int = -1;
+    let c_termios = match &termios {
+        &Some(ref termios) => termios as *const Termios,
+        &None => 0 as *const Termios,
+    };
+    let c_winsize = match &winsize {
+        &Some(ref ws) => ws as *const Winsize,
+        &None => 0 as *const Winsize,
+    };
+    let ret = unsafe {
+        libc::openpty(
+            &mut master as *mut libc::c_int,
+            &mut slave as *mut libc::c_int,
+            0 as *mut libc::c_char,
+            c_termios as *const libc::termios,
+            c_winsize)
+    };
+
+    let _ = try!(Errno::result(ret));
+
+    Ok(OpenptyResult {
+        master: master,
+        slave: slave,
+    })
+}
diff --git a/test/test.rs b/test/test.rs
index 045f8f1837..5063ee00b2 100644
--- a/test/test.rs
+++ b/test/test.rs
@@ -11,6 +11,7 @@ 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();
+}

From e1974793cadce05c98b04b9143017026eb76a5fe Mon Sep 17 00:00:00 2001
From: Kelvin Ly <kelvin.ly1618@gmail.com>
Date: Wed, 2 Nov 2016 09:39:29 -0400
Subject: [PATCH 2/3] Add documentation for openpty

---
 src/pty.rs | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/src/pty.rs b/src/pty.rs
index 04fd05b1df..343323b5b5 100644
--- a/src/pty.rs
+++ b/src/pty.rs
@@ -13,6 +13,13 @@ pub struct OpenptyResult {
     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(winsize: Option<Winsize>, termios: Option<Termios>) -> Result<OpenptyResult> {
     let mut slave: libc::c_int = -1;

From bc019895099cad79b2f2e9c79cae39f822dc3285 Mon Sep 17 00:00:00 2001
From: Kelvin Ly <kelvin.ly1618@gmail.com>
Date: Wed, 2 Nov 2016 10:04:56 -0400
Subject: [PATCH 3/3] Fix mutability problem with openpty FFI

---
 src/pty.rs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/pty.rs b/src/pty.rs
index 343323b5b5..535444357d 100644
--- a/src/pty.rs
+++ b/src/pty.rs
@@ -37,8 +37,8 @@ pub fn openpty(winsize: Option<Winsize>, termios: Option<Termios>) -> Result<Ope
             &mut master as *mut libc::c_int,
             &mut slave as *mut libc::c_int,
             0 as *mut libc::c_char,
-            c_termios as *const libc::termios,
-            c_winsize)
+            c_termios as *mut libc::termios,
+            c_winsize as *mut Winsize)
     };
 
     let _ = try!(Errno::result(ret));