Add support for Windows (#1374)

Initial support for Windows is implemented using the winpty translation
layer. Clipboard support for Windows is provided through the `clipboard`
crate, and font rasterization is provided by RustType.

The tty.rs file has been split into OS-specific files to separate
standard pty handling from the winpty implementation.

Several binary components are fetched via build script on windows
including libclang and winpty. These could be integrated more directly
in the future either by building those dependencies as part of the
Alacritty build process or by leveraging git lfs to store the artifacts.

Fixes #28.

1 files changed, 429 insertions, 0 deletions

diff --git a/src/tty/unix.rs b/src/tty/unix.rs
new file mode 100644
index 00000000..08a2c4f3
--- /dev/null
+++ b/src/tty/unix.rs
@@ -0,0 +1,429 @@
+// Copyright 2016 Joe Wilm, The Alacritty Project Contributors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+//! tty related functionality
+//!
+
+use tty::EventedReadWrite;
+use term::SizeInfo;
+use display::OnResize;
+use config::{Config, Shell};
+use cli::Options;
+use mio;
+
+use libc::{self, c_int, pid_t, winsize, SIGCHLD, TIOCSCTTY, WNOHANG};
+use terminfo::Database;
+
+use std::os::unix::io::{FromRawFd, RawFd};
+use std::fs::File;
+use std::os::unix::process::CommandExt;
+use std::process::{Command, Stdio};
+use std::ffi::CStr;
+use std::ptr;
+use mio::unix::EventedFd;
+use std::io;
+use std::os::unix::io::AsRawFd;
+
+
+/// Process ID of child process
+///
+/// Necessary to put this in static storage for `sigchld` to have access
+static mut PID: pid_t = 0;
+
+/// Exit flag
+///
+/// Calling exit() in the SIGCHLD handler sometimes causes opengl to deadlock,
+/// and the process hangs. Instead, this flag is set, and its status can be
+/// checked via `process_should_exit`.
+static mut SHOULD_EXIT: bool = false;
+
+extern "C" fn sigchld(_a: c_int) {
+    let mut status: c_int = 0;
+    unsafe {
+        let p = libc::waitpid(PID, &mut status, WNOHANG);
+        if p < 0 {
+            die!("Waiting for pid {} failed: {}\n", PID, errno());
+        }
+
+        if PID == p {
+            SHOULD_EXIT = true;
+        }
+    }
+}
+
+pub fn process_should_exit() -> bool {
+    unsafe { SHOULD_EXIT }
+}
+
+/// Get the current value of errno
+fn errno() -> c_int {
+    ::errno::errno().0
+}
+
+/// Get raw fds for master/slave ends of a new pty
+#[cfg(target_os = "linux")]
+fn openpty(rows: u8, cols: u8) -> (c_int, c_int) {
+    let mut master: c_int = 0;
+    let mut slave: c_int = 0;
+
+    let win = winsize {
+        ws_row: libc::c_ushort::from(rows),
+        ws_col: libc::c_ushort::from(cols),
+        ws_xpixel: 0,
+        ws_ypixel: 0,
+    };
+
+    let res = unsafe {
+        libc::openpty(&mut master, &mut slave, ptr::null_mut(), ptr::null(), &win)
+    };
+
+    if res < 0 {
+        die!("openpty failed");
+    }
+
+    (master, slave)
+}
+
+#[cfg(any(target_os = "macos",target_os = "freebsd",target_os = "openbsd"))]
+fn openpty(rows: u8, cols: u8) -> (c_int, c_int) {
+    let mut master: c_int = 0;
+    let mut slave: c_int = 0;
+
+    let mut win = winsize {
+        ws_row: libc::c_ushort::from(rows),
+        ws_col: libc::c_ushort::from(cols),
+        ws_xpixel: 0,
+        ws_ypixel: 0,
+    };
+
+    let res = unsafe {
+        libc::openpty(&mut master, &mut slave, ptr::null_mut(), ptr::null_mut(), &mut win)
+    };
+
+    if res < 0 {
+        die!("openpty failed");
+    }
+
+    (master, slave)
+}
+
+/// Really only needed on BSD, but should be fine elsewhere
+fn set_controlling_terminal(fd: c_int) {
+    let res = unsafe {
+        // TIOSCTTY changes based on platform and the `ioctl` call is different
+        // based on architecture (32/64). So a generic cast is used to make sure
+        // there are no issues. To allow such a generic cast the clippy warning
+        // is disabled.
+        #[cfg_attr(feature = "cargo-clippy", allow(cast_lossless))]
+        libc::ioctl(fd, TIOCSCTTY as _, 0)
+    };
+
+    if res < 0 {
+        die!("ioctl TIOCSCTTY failed: {}", errno());
+    }
+}
+
+#[derive(Debug)]
+struct Passwd<'a> {
+    name: &'a str,
+    passwd: &'a str,
+    uid: libc::uid_t,
+    gid: libc::gid_t,
+    gecos: &'a str,
+    dir: &'a str,
+    shell: &'a str,
+}
+
+/// Return a Passwd struct with pointers into the provided buf
+///
+/// # Unsafety
+///
+/// If `buf` is changed while `Passwd` is alive, bad thing will almost certainly happen.
+fn get_pw_entry(buf: &mut [i8; 1024]) -> Passwd {
+    // Create zeroed passwd struct
+    let mut entry: libc::passwd = unsafe { ::std::mem::uninitialized() };
+
+    let mut res: *mut libc::passwd = ptr::null_mut();
+
+    // Try and read the pw file.
+    let uid = unsafe { libc::getuid() };
+    let status = unsafe {
+        libc::getpwuid_r(uid, &mut entry, buf.as_mut_ptr() as *mut _, buf.len(), &mut res)
+    };
+
+    if status < 0 {
+        die!("getpwuid_r failed");
+    }
+
+    if res.is_null() {
+        die!("pw not found");
+    }
+
+    // sanity check
+    assert_eq!(entry.pw_uid, uid);
+
+    // Build a borrowed Passwd struct
+    Passwd {
+        name: unsafe { CStr::from_ptr(entry.pw_name).to_str().unwrap() },
+        passwd: unsafe { CStr::from_ptr(entry.pw_passwd).to_str().unwrap() },
+        uid: entry.pw_uid,
+        gid: entry.pw_gid,
+        gecos: unsafe { CStr::from_ptr(entry.pw_gecos).to_str().unwrap() },
+        dir: unsafe { CStr::from_ptr(entry.pw_dir).to_str().unwrap() },
+        shell: unsafe { CStr::from_ptr(entry.pw_shell).to_str().unwrap() },
+    }
+}
+
+pub struct Pty {
+    pub fd: File,
+    pub raw_fd: RawFd,
+    token: mio::Token,
+}
+
+impl Pty {
+    /// Resize the pty
+    ///
+    /// Tells the kernel that the window size changed with the new pixel
+    /// dimensions and line/column counts.
+    pub fn resize<T: ToWinsize>(&self, size: &T) {
+        let win = size.to_winsize();
+
+        let res = unsafe {
+            libc::ioctl(self.fd.as_raw_fd(), libc::TIOCSWINSZ, &win as *const _)
+        };
+
+        if res < 0 {
+            die!("ioctl TIOCSWINSZ failed: {}", errno());
+        }
+    }
+}
+
+/// Create a new tty and return a handle to interact with it.
+pub fn new<T: ToWinsize>(
+    config: &Config,
+    options: &Options,
+    size: &T,
+    window_id: Option<usize>,
+) -> Pty {
+    let win = size.to_winsize();
+    let mut buf = [0; 1024];
+    let pw = get_pw_entry(&mut buf);
+
+    let (master, slave) = openpty(win.ws_row as _, win.ws_col as _);
+
+    let default_shell = &Shell::new(pw.shell);
+    let shell = config.shell()
+        .unwrap_or(default_shell);
+
+    let initial_command = options.command().unwrap_or(shell);
+
+    let mut builder = Command::new(initial_command.program());
+    for arg in initial_command.args() {
+        builder.arg(arg);
+    }
+
+    // Setup child stdin/stdout/stderr as slave fd of pty
+    // Ownership of fd is transferred to the Stdio structs and will be closed by them at the end of
+    // this scope. (It is not an issue that the fd is closed three times since File::drop ignores
+    // error on libc::close.)
+    builder.stdin(unsafe { Stdio::from_raw_fd(slave) });
+    builder.stderr(unsafe { Stdio::from_raw_fd(slave) });
+    builder.stdout(unsafe { Stdio::from_raw_fd(slave) });
+
+    // Setup environment
+    builder.env("LOGNAME", pw.name);
+    builder.env("USER", pw.name);
+    builder.env("SHELL", shell.program());
+    builder.env("HOME", pw.dir);
+
+    // TERM; default to 'alacritty' if it is available, otherwise
+    // default to 'xterm-256color'. May be overridden by user's config
+    // below.
+    let term = if Database::from_name("alacritty").is_ok() {
+        "alacritty"
+    } else {
+        "xterm-256color"
+    };
+    builder.env("TERM", term);
+
+    builder.env("COLORTERM", "truecolor"); // advertise 24-bit support
+    if let Some(window_id) = window_id {
+        builder.env("WINDOWID", format!("{}", window_id));
+    }
+    for (key, value) in config.env().iter() {
+        builder.env(key, value);
+    }
+
+    builder.before_exec(move || {
+        // Create a new process group
+        unsafe {
+            let err = libc::setsid();
+            if err == -1 {
+                die!("Failed to set session id: {}", errno());
+            }
+        }
+
+        set_controlling_terminal(slave);
+
+        // No longer need slave/master fds
+        unsafe {
+            libc::close(slave);
+            libc::close(master);
+        }
+
+        unsafe {
+            libc::signal(libc::SIGCHLD, libc::SIG_DFL);
+            libc::signal(libc::SIGHUP, libc::SIG_DFL);
+            libc::signal(libc::SIGINT, libc::SIG_DFL);
+            libc::signal(libc::SIGQUIT, libc::SIG_DFL);
+            libc::signal(libc::SIGTERM, libc::SIG_DFL);
+            libc::signal(libc::SIGALRM, libc::SIG_DFL);
+        }
+        Ok(())
+    });
+
+    // Handle set working directory option
+    if let Some(ref dir) = options.working_dir {
+        builder.current_dir(dir.as_path());
+    }
+
+    match builder.spawn() {
+        Ok(child) => {
+            unsafe {
+                // Set PID for SIGCHLD handler
+                PID = child.id() as _;
+
+                // Handle SIGCHLD
+                libc::signal(SIGCHLD, sigchld as _);
+            }
+            unsafe {
+                // Maybe this should be done outside of this function so nonblocking
+                // isn't forced upon consumers. Although maybe it should be?
+                set_nonblocking(master);
+            }
+
+            let pty = Pty {
+                fd: unsafe {File::from_raw_fd(master) },
+                raw_fd: master,
+                token: mio::Token::from(0)
+            };
+            pty.resize(size);
+            pty
+        },
+        Err(err) => {
+            die!("Command::spawn() failed: {}", err);
+        }
+    }
+}
+
+impl EventedReadWrite for Pty {
+    type Reader = File;
+    type Writer = File;
+
+    #[inline]
+    fn register(
+        &mut self,
+        poll: &mio::Poll,
+        token: &mut Iterator<Item = &usize>,
+        interest: mio::Ready,
+        poll_opts: mio::PollOpt,
+    ) -> io::Result<()> {
+        self.token = (*token.next().unwrap()).into();
+        poll.register(
+            &EventedFd(&self.raw_fd),
+            self.token,
+            interest,
+            poll_opts
+        )
+    }
+
+    #[inline]
+    fn reregister(&mut self, poll: &mio::Poll, interest: mio::Ready, poll_opts: mio::PollOpt) -> io::Result<()> {
+        poll.reregister(
+            &EventedFd(&self.raw_fd),
+            self.token,
+            interest,
+            poll_opts
+        )
+    }
+
+    #[inline]
+    fn deregister(&mut self, poll: &mio::Poll) -> io::Result<()> {
+        poll.deregister(&EventedFd(&self.raw_fd))
+    }
+
+    #[inline]
+    fn reader(&mut self) -> &mut File {
+        &mut self.fd
+    }
+
+    #[inline]
+    fn read_token(&self) -> mio::Token {
+        self.token
+    }
+
+    #[inline]
+    fn writer(&mut self) -> &mut File {
+        &mut self.fd
+    }
+
+    #[inline]
+    fn write_token(&self) -> mio::Token {
+        self.token
+    }
+}
+
+/// Types that can produce a `libc::winsize`
+pub trait ToWinsize {
+    /// Get a `libc::winsize`
+    fn to_winsize(&self) -> winsize;
+}
+
+impl<'a> ToWinsize for &'a SizeInfo {
+    fn to_winsize(&self) -> winsize {
+        winsize {
+            ws_row: self.lines().0 as libc::c_ushort,
+            ws_col: self.cols().0 as libc::c_ushort,
+            ws_xpixel: self.width as libc::c_ushort,
+            ws_ypixel: self.height as libc::c_ushort,
+        }
+    }
+}
+
+impl OnResize for i32 {
+    fn on_resize(&mut self, size: &SizeInfo) {
+        let win = size.to_winsize();
+
+        let res = unsafe {
+            libc::ioctl(*self, libc::TIOCSWINSZ, &win as *const _)
+        };
+
+        if res < 0 {
+            die!("ioctl TIOCSWINSZ failed: {}", errno());
+        }
+    }
+}
+
+unsafe fn set_nonblocking(fd: c_int) {
+    use libc::{fcntl, F_GETFL, F_SETFL, O_NONBLOCK};
+
+    let res = fcntl(fd, F_SETFL, fcntl(fd, F_GETFL, 0) | O_NONBLOCK);
+    assert_eq!(res, 0);
+}
+
+#[test]
+fn test_get_pw_entry() {
+    let mut buf: [i8; 1024] = [0; 1024];
+    let _pw = get_pw_entry(&mut buf);
+}