Separated fuchsia-specific process stuff into 'process_fuchsia.rs' and refactored out some now-duplicated code into a 'process_common.rs'

6 files changed, 940 insertions, 868 deletions

diff --git a/src/libstd/sys/unix/magenta.rs b/src/libstd/sys/unix/magenta.rs
index 9da827c7d31..155259d2645 100644
--- a/src/libstd/sys/unix/magenta.rs
+++ b/src/libstd/sys/unix/magenta.rs
@@ -67,7 +67,6 @@ pub struct mx_info_process_t {
     pub rec: mx_record_process_t,
 }
 
-#[link(name = "magenta")]
 extern {
     pub fn mx_handle_close(handle: mx_handle_t) -> mx_status_t;
 
@@ -89,7 +88,6 @@ pub fn mx_hnd_info(hnd_type: u32, arg: u32) -> u32 {
     (hnd_type & 0xFFFF) | ((arg & 0xFFFF) << 16)
 }
 
-#[link(name="mxio")]
 extern {
     pub fn mxio_get_startup_handle(id: u32) -> mx_handle_t;
 }
@@ -123,7 +121,6 @@ pub struct launchpad_t {
     loader_message: bool,
 }
 
-#[link(name="launchpad")]
 extern {
     pub fn launchpad_create(job: mx_handle_t, name: *const c_char,
                             lp: *mut *mut launchpad_t) -> mx_status_t;
diff --git a/src/libstd/sys/unix/process.rs b/src/libstd/sys/unix/process.rs
deleted file mode 100644
index d660514a983..00000000000
--- a/src/libstd/sys/unix/process.rs
+++ /dev/null
@@ -1,865 +0,0 @@
-// Copyright 2014-2015 The Rust Project Developers. See the COPYRIGHT
-// file at the top-level directory of this distribution and at
-// http://rust-lang.org/COPYRIGHT.
-//
-// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
-// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
-// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
-// option. This file may not be copied, modified, or distributed
-// except according to those terms.
-
-use os::unix::prelude::*;
-
-use collections::hash_map::{HashMap, Entry};
-use env;
-use ffi::{OsString, OsStr, CString, CStr};
-use fmt;
-use io::{self, Error, ErrorKind};
-use libc::{self, c_int, gid_t, uid_t, c_char};
-use mem;
-use ptr;
-use sys::fd::FileDesc;
-use sys::fs::{File, OpenOptions};
-use sys::pipe::{self, AnonPipe};
-
-#[cfg(not(target_os = "fuchsia"))]
-use sys::cvt;
-#[cfg(target_os = "fuchsia")]
-use sys::mx_cvt;
-
-#[cfg(target_os = "fuchsia")]
-use sys::magenta::{launchpad_t, mx_handle_t};
-
-#[cfg(not(target_os = "fuchsia"))]
-use libc::pid_t;
-
-////////////////////////////////////////////////////////////////////////////////
-// Command
-////////////////////////////////////////////////////////////////////////////////
-
-pub struct Command {
-    // Currently we try hard to ensure that the call to `.exec()` doesn't
-    // actually allocate any memory. While many platforms try to ensure that
-    // memory allocation works after a fork in a multithreaded process, it's
-    // been observed to be buggy and somewhat unreliable, so we do our best to
-    // just not do it at all!
-    //
-    // Along those lines, the `argv` and `envp` raw pointers here are exactly
-    // what's gonna get passed to `execvp`. The `argv` array starts with the
-    // `program` and ends with a NULL, and the `envp` pointer, if present, is
-    // also null-terminated.
-    //
-    // Right now we don't support removing arguments, so there's no much fancy
-    // support there, but we support adding and removing environment variables,
-    // so a side table is used to track where in the `envp` array each key is
-    // located. Whenever we add a key we update it in place if it's already
-    // present, and whenever we remove a key we update the locations of all
-    // other keys.
-    program: CString,
-    args: Vec<CString>,
-    env: Option<HashMap<OsString, (usize, CString)>>,
-    argv: Vec<*const c_char>,
-    envp: Option<Vec<*const c_char>>,
-
-    cwd: Option<CString>,
-    uid: Option<uid_t>,
-    gid: Option<gid_t>,
-    saw_nul: bool,
-    closures: Vec<Box<FnMut() -> io::Result<()> + Send + Sync>>,
-    stdin: Option<Stdio>,
-    stdout: Option<Stdio>,
-    stderr: Option<Stdio>,
-}
-
-// passed back to std::process with the pipes connected to the child, if any
-// were requested
-pub struct StdioPipes {
-    pub stdin: Option<AnonPipe>,
-    pub stdout: Option<AnonPipe>,
-    pub stderr: Option<AnonPipe>,
-}
-
-// passed to do_exec() with configuration of what the child stdio should look
-// like
-struct ChildPipes {
-    stdin: ChildStdio,
-    stdout: ChildStdio,
-    stderr: ChildStdio,
-}
-
-enum ChildStdio {
-    Inherit,
-    Explicit(c_int),
-    Owned(FileDesc),
-}
-
-pub enum Stdio {
-    Inherit,
-    Null,
-    MakePipe,
-    Fd(FileDesc),
-}
-
-impl Command {
-    pub fn new(program: &OsStr) -> Command {
-        let mut saw_nul = false;
-        let program = os2c(program, &mut saw_nul);
-        Command {
-            argv: vec![program.as_ptr(), ptr::null()],
-            program: program,
-            args: Vec::new(),
-            env: None,
-            envp: None,
-            cwd: None,
-            uid: None,
-            gid: None,
-            saw_nul: saw_nul,
-            closures: Vec::new(),
-            stdin: None,
-            stdout: None,
-            stderr: None,
-        }
-    }
-
-    pub fn arg(&mut self, arg: &OsStr) {
-        // Overwrite the trailing NULL pointer in `argv` and then add a new null
-        // pointer.
-        let arg = os2c(arg, &mut self.saw_nul);
-        self.argv[self.args.len() + 1] = arg.as_ptr();
-        self.argv.push(ptr::null());
-
-        // Also make sure we keep track of the owned value to schedule a
-        // destructor for this memory.
-        self.args.push(arg);
-    }
-
-    fn init_env_map(&mut self) -> (&mut HashMap<OsString, (usize, CString)>,
-                                   &mut Vec<*const c_char>) {
-        if self.env.is_none() {
-            let mut map = HashMap::new();
-            let mut envp = Vec::new();
-            for (k, v) in env::vars_os() {
-                let s = pair_to_key(&k, &v, &mut self.saw_nul);
-                envp.push(s.as_ptr());
-                map.insert(k, (envp.len() - 1, s));
-            }
-            envp.push(ptr::null());
-            self.env = Some(map);
-            self.envp = Some(envp);
-        }
-        (self.env.as_mut().unwrap(), self.envp.as_mut().unwrap())
-    }
-
-    pub fn env(&mut self, key: &OsStr, val: &OsStr) {
-        let new_key = pair_to_key(key, val, &mut self.saw_nul);
-        let (map, envp) = self.init_env_map();
-
-        // If `key` is already present then we just update `envp` in place
-        // (and store the owned value), but if it's not there we override the
-        // trailing NULL pointer, add a new NULL pointer, and store where we
-        // were located.
-        match map.entry(key.to_owned()) {
-            Entry::Occupied(mut e) => {
-                let (i, ref mut s) = *e.get_mut();
-                envp[i] = new_key.as_ptr();
-                *s = new_key;
-            }
-            Entry::Vacant(e) => {
-                let len = envp.len();
-                envp[len - 1] = new_key.as_ptr();
-                envp.push(ptr::null());
-                e.insert((len - 1, new_key));
-            }
-        }
-    }
-
-    pub fn env_remove(&mut self, key: &OsStr) {
-        let (map, envp) = self.init_env_map();
-
-        // If we actually ended up removing a key, then we need to update the
-        // position of all keys that come after us in `envp` because they're all
-        // one element sooner now.
-        if let Some((i, _)) = map.remove(key) {
-            envp.remove(i);
-
-            for (_, &mut (ref mut j, _)) in map.iter_mut() {
-                if *j >= i {
-                    *j -= 1;
-                }
-            }
-        }
-    }
-
-    pub fn env_clear(&mut self) {
-        self.env = Some(HashMap::new());
-        self.envp = Some(vec![ptr::null()]);
-    }
-
-    pub fn cwd(&mut self, dir: &OsStr) {
-        self.cwd = Some(os2c(dir, &mut self.saw_nul));
-    }
-    pub fn uid(&mut self, id: uid_t) {
-        self.uid = Some(id);
-    }
-    pub fn gid(&mut self, id: gid_t) {
-        self.gid = Some(id);
-    }
-
-    pub fn before_exec(&mut self,
-                       f: Box<FnMut() -> io::Result<()> + Send + Sync>) {
-        self.closures.push(f);
-    }
-
-    pub fn stdin(&mut self, stdin: Stdio) {
-        self.stdin = Some(stdin);
-    }
-    pub fn stdout(&mut self, stdout: Stdio) {
-        self.stdout = Some(stdout);
-    }
-    pub fn stderr(&mut self, stderr: Stdio) {
-        self.stderr = Some(stderr);
-    }
-
-    #[cfg(not(target_os = "fuchsia"))]
-    pub fn spawn(&mut self, default: Stdio, needs_stdin: bool)
-                 -> io::Result<(Process, StdioPipes)> {
-        use sys;
-
-        const CLOEXEC_MSG_FOOTER: &'static [u8] = b"NOEX";
-
-        if self.saw_nul {
-            return Err(io::Error::new(ErrorKind::InvalidInput,
-                                      "nul byte found in provided data"));
-        }
-
-        let (ours, theirs) = self.setup_io(default, needs_stdin)?;
-        let (input, output) = sys::pipe::anon_pipe()?;
-
-        let pid = unsafe {
-            match cvt(libc::fork())? {
-                0 => {
-                    drop(input);
-                    let err = self.do_exec(theirs);
-                    let errno = err.raw_os_error().unwrap_or(libc::EINVAL) as u32;
-                    let bytes = [
-                        (errno >> 24) as u8,
-                        (errno >> 16) as u8,
-                        (errno >>  8) as u8,
-                        (errno >>  0) as u8,
-                        CLOEXEC_MSG_FOOTER[0], CLOEXEC_MSG_FOOTER[1],
-                        CLOEXEC_MSG_FOOTER[2], CLOEXEC_MSG_FOOTER[3]
-                    ];
-                    // pipe I/O up to PIPE_BUF bytes should be atomic, and then
-                    // we want to be sure we *don't* run at_exit destructors as
-                    // we're being torn down regardless
-                    assert!(output.write(&bytes).is_ok());
-                    libc::_exit(1)
-                }
-                n => n,
-            }
-        };
-
-        let mut p = Process { pid: pid, status: None };
-        drop(output);
-        let mut bytes = [0; 8];
-
-        // loop to handle EINTR
-        loop {
-            match input.read(&mut bytes) {
-                Ok(0) => return Ok((p, ours)),
-                Ok(8) => {
-                    assert!(combine(CLOEXEC_MSG_FOOTER) == combine(&bytes[4.. 8]),
-                            "Validation on the CLOEXEC pipe failed: {:?}", bytes);
-                    let errno = combine(&bytes[0.. 4]);
-                    assert!(p.wait().is_ok(),
-                            "wait() should either return Ok or panic");
-                    return Err(Error::from_raw_os_error(errno))
-                }
-                Err(ref e) if e.kind() == ErrorKind::Interrupted => {}
-                Err(e) => {
-                    assert!(p.wait().is_ok(),
-                            "wait() should either return Ok or panic");
-                    panic!("the CLOEXEC pipe failed: {:?}", e)
-                },
-                Ok(..) => { // pipe I/O up to PIPE_BUF bytes should be atomic
-                    assert!(p.wait().is_ok(),
-                            "wait() should either return Ok or panic");
-                    panic!("short read on the CLOEXEC pipe")
-                }
-            }
-        }
-
-        fn combine(arr: &[u8]) -> i32 {
-            let a = arr[0] as u32;
-            let b = arr[1] as u32;
-            let c = arr[2] as u32;
-            let d = arr[3] as u32;
-
-            ((a << 24) | (b << 16) | (c << 8) | (d << 0)) as i32
-        }
-    }
-
-    #[cfg(target_os = "fuchsia")]
-    pub fn spawn(&mut self, default: Stdio, needs_stdin: bool)
-                 -> io::Result<(Process, StdioPipes)> {
-        if self.saw_nul {
-            return Err(io::Error::new(ErrorKind::InvalidInput,
-                                      "nul byte found in provided data"));
-        }
-
-        let (ours, theirs) = self.setup_io(default, needs_stdin)?;
-
-        let (launchpad, process_handle) = unsafe { self.do_exec(theirs)? };
-
-        Ok((Process { launchpad: launchpad, handle: process_handle, status: None }, ours))
-    }
-
-    #[cfg(not(target_os = "fuchsia"))]
-    pub fn exec(&mut self, default: Stdio) -> io::Error {
-        if self.saw_nul {
-            return io::Error::new(ErrorKind::InvalidInput,
-                                  "nul byte found in provided data")
-        }
-
-        match self.setup_io(default, true) {
-            Ok((_, theirs)) => unsafe { self.do_exec(theirs) },
-            Err(e) => e,
-        }
-    }
-
-    #[cfg(target_os = "fuchsia")]
-    pub fn exec(&mut self, default: Stdio) -> io::Error {
-        if self.saw_nul {
-            return io::Error::new(ErrorKind::InvalidInput,
-                                  "nul byte found in provided data")
-        }
-
-        match self.setup_io(default, true) {
-            Ok((_, _)) => {
-                // FIXME: This is tough because we don't support the exec syscalls
-                unimplemented!();
-            },
-            Err(e) => e,
-        }
-    }
-
-    // And at this point we've reached a special time in the life of the
-    // child. The child must now be considered hamstrung and unable to
-    // do anything other than syscalls really. Consider the following
-    // scenario:
-    //
-    //      1. Thread A of process 1 grabs the malloc() mutex
-    //      2. Thread B of process 1 forks(), creating thread C
-    //      3. Thread C of process 2 then attempts to malloc()
-    //      4. The memory of process 2 is the same as the memory of
-    //         process 1, so the mutex is locked.
-    //
-    // This situation looks a lot like deadlock, right? It turns out
-    // that this is what pthread_atfork() takes care of, which is
-    // presumably implemented across platforms. The first thing that
-    // threads to *before* forking is to do things like grab the malloc
-    // mutex, and then after the fork they unlock it.
-    //
-    // Despite this information, libnative's spawn has been witnessed to
-    // deadlock on both OSX and FreeBSD. I'm not entirely sure why, but
-    // all collected backtraces point at malloc/free traffic in the
-    // child spawned process.
-    //
-    // For this reason, the block of code below should contain 0
-    // invocations of either malloc of free (or their related friends).
-    //
-    // As an example of not having malloc/free traffic, we don't close
-    // this file descriptor by dropping the FileDesc (which contains an
-    // allocation). Instead we just close it manually. This will never
-    // have the drop glue anyway because this code never returns (the
-    // child will either exec() or invoke libc::exit)
-    #[cfg(not(target_os = "fuchsia"))]
-    unsafe fn do_exec(&mut self, stdio: ChildPipes) -> io::Error {
-        use sys::{self, cvt_r};
-
-        macro_rules! t {
-            ($e:expr) => (match $e {
-                Ok(e) => e,
-                Err(e) => return e,
-            })
-        }
-
-        if let Some(fd) = stdio.stdin.fd() {
-            t!(cvt_r(|| libc::dup2(fd, libc::STDIN_FILENO)));
-        }
-        if let Some(fd) = stdio.stdout.fd() {
-            t!(cvt_r(|| libc::dup2(fd, libc::STDOUT_FILENO)));
-        }
-        if let Some(fd) = stdio.stderr.fd() {
-            t!(cvt_r(|| libc::dup2(fd, libc::STDERR_FILENO)));
-        }
-
-        if let Some(u) = self.gid {
-            t!(cvt(libc::setgid(u as gid_t)));
-        }
-        if let Some(u) = self.uid {
-            // When dropping privileges from root, the `setgroups` call
-            // will remove any extraneous groups. If we don't call this,
-            // then even though our uid has dropped, we may still have
-            // groups that enable us to do super-user things. This will
-            // fail if we aren't root, so don't bother checking the
-            // return value, this is just done as an optimistic
-            // privilege dropping function.
-            let _ = libc::setgroups(0, ptr::null());
-
-            t!(cvt(libc::setuid(u as uid_t)));
-        }
-        if let Some(ref cwd) = self.cwd {
-            t!(cvt(libc::chdir(cwd.as_ptr())));
-        }
-        if let Some(ref envp) = self.envp {
-            *sys::os::environ() = envp.as_ptr();
-        }
-
-        // NaCl has no signal support.
-        if cfg!(not(any(target_os = "nacl", target_os = "emscripten"))) {
-            // Reset signal handling so the child process starts in a
-            // standardized state. libstd ignores SIGPIPE, and signal-handling
-            // libraries often set a mask. Child processes inherit ignored
-            // signals and the signal mask from their parent, but most
-            // UNIX programs do not reset these things on their own, so we
-            // need to clean things up now to avoid confusing the program
-            // we're about to run.
-            let mut set: libc::sigset_t = mem::uninitialized();
-            t!(cvt(libc::sigemptyset(&mut set)));
-            t!(cvt(libc::pthread_sigmask(libc::SIG_SETMASK, &set,
-                                         ptr::null_mut())));
-            let ret = super::signal(libc::SIGPIPE, libc::SIG_DFL);
-            if ret == libc::SIG_ERR {
-                return io::Error::last_os_error()
-            }
-        }
-
-        for callback in self.closures.iter_mut() {
-            t!(callback());
-        }
-
-        libc::execvp(self.argv[0], self.argv.as_ptr());
-        io::Error::last_os_error()
-    }
-
-    #[cfg(target_os = "fuchsia")]
-    unsafe fn do_exec(&mut self, stdio: ChildPipes)
-                      -> io::Result<(*mut launchpad_t, mx_handle_t)> {
-        use sys::magenta::*;
-
-        macro_rules! tlp {
-            ($lp:expr, $e:expr) => (match $e {
-                Ok(e) => e,
-                Err(e) => {
-                    launchpad_destroy($lp);
-                    return Err(e);
-                },
-            })
-        }
-
-        let job_handle = mxio_get_startup_handle(mx_hnd_info(MX_HND_TYPE_JOB, 0));
-        let envp = match self.envp {
-            Some(ref envp) => envp.as_ptr(),
-            None => ptr::null(),
-        };
-
-        let mut launchpad: *mut launchpad_t = ptr::null_mut();
-        let mut job_copy: mx_handle_t = MX_HANDLE_INVALID;
-
-        // Duplicate the job handle
-        mx_cvt(mx_handle_duplicate(job_handle, MX_RIGHT_SAME_RIGHTS,
-                                   &mut job_copy as *mut mx_handle_t))?;
-        // Create a launchpad
-        mx_cvt(launchpad_create(job_copy, self.argv[0],
-                                &mut launchpad as *mut *mut launchpad_t))?;
-        // Set the process argv
-        tlp!(launchpad, mx_cvt(launchpad_arguments(launchpad, self.argv.len() as i32 - 1,
-                                                   self.argv.as_ptr())));
-        // Setup the environment vars
-        tlp!(launchpad, mx_cvt(launchpad_environ(launchpad, envp)));
-        tlp!(launchpad, mx_cvt(launchpad_add_vdso_vmo(launchpad)));
-        tlp!(launchpad, mx_cvt(launchpad_clone_mxio_root(launchpad)));
-        // Load the executable
-        tlp!(launchpad,
-             mx_cvt(launchpad_elf_load(launchpad, launchpad_vmo_from_file(self.argv[0]))));
-        tlp!(launchpad, mx_cvt(launchpad_load_vdso(launchpad, MX_HANDLE_INVALID)));
-        tlp!(launchpad, mx_cvt(launchpad_clone_mxio_cwd(launchpad)));
-
-        // Clone stdin, stdout, and stderr
-        if let Some(fd) = stdio.stdin.fd() {
-            launchpad_transfer_fd(launchpad, fd, 0);
-        } else {
-            launchpad_clone_fd(launchpad, 0, 0);
-        }
-        if let Some(fd) = stdio.stdout.fd() {
-            launchpad_transfer_fd(launchpad, fd, 1);
-        } else {
-            launchpad_clone_fd(launchpad, 1, 1);
-        }
-        if let Some(fd) = stdio.stderr.fd() {
-            launchpad_transfer_fd(launchpad, fd, 2);
-        } else {
-            launchpad_clone_fd(launchpad, 2, 2);
-        }
-
-        // We don't want FileDesc::drop to be called on any stdio. It would close their fds. The
-        // fds will be closed once the child process finishes.
-        let ChildPipes { stdin: child_stdin, stdout: child_stdout, stderr: child_stderr } = stdio;
-        if let ChildStdio::Owned(fd) = child_stdin { fd.into_raw(); }
-        if let ChildStdio::Owned(fd) = child_stdout { fd.into_raw(); }
-        if let ChildStdio::Owned(fd) = child_stderr { fd.into_raw(); }
-
-        for callback in self.closures.iter_mut() {
-            callback()?;
-        }
-
-        let process_handle = tlp!(launchpad, mx_cvt(launchpad_start(launchpad)));
-
-        Ok((launchpad, process_handle))
-    }
-
-    fn setup_io(&self, default: Stdio, needs_stdin: bool)
-                -> io::Result<(StdioPipes, ChildPipes)> {
-        let null = Stdio::Null;
-        let default_stdin = if needs_stdin {&default} else {&null};
-        let stdin = self.stdin.as_ref().unwrap_or(default_stdin);
-        let stdout = self.stdout.as_ref().unwrap_or(&default);
-        let stderr = self.stderr.as_ref().unwrap_or(&default);
-        let (their_stdin, our_stdin) = stdin.to_child_stdio(true)?;
-        let (their_stdout, our_stdout) = stdout.to_child_stdio(false)?;
-        let (their_stderr, our_stderr) = stderr.to_child_stdio(false)?;
-        let ours = StdioPipes {
-            stdin: our_stdin,
-            stdout: our_stdout,
-            stderr: our_stderr,
-        };
-        let theirs = ChildPipes {
-            stdin: their_stdin,
-            stdout: their_stdout,
-            stderr: their_stderr,
-        };
-        Ok((ours, theirs))
-    }
-}
-
-fn os2c(s: &OsStr, saw_nul: &mut bool) -> CString {
-    CString::new(s.as_bytes()).unwrap_or_else(|_e| {
-        *saw_nul = true;
-        CString::new("<string-with-nul>").unwrap()
-    })
-}
-
-impl Stdio {
-    fn to_child_stdio(&self, readable: bool)
-                      -> io::Result<(ChildStdio, Option<AnonPipe>)> {
-        match *self {
-            Stdio::Inherit => {
-                Ok((ChildStdio::Inherit, None))
-            },
-
-            // Make sure that the source descriptors are not an stdio
-            // descriptor, otherwise the order which we set the child's
-            // descriptors may blow away a descriptor which we are hoping to
-            // save. For example, suppose we want the child's stderr to be the
-            // parent's stdout, and the child's stdout to be the parent's
-            // stderr. No matter which we dup first, the second will get
-            // overwritten prematurely.
-            Stdio::Fd(ref fd) => {
-                if fd.raw() >= 0 && fd.raw() <= libc::STDERR_FILENO {
-                    Ok((ChildStdio::Owned(fd.duplicate()?), None))
-                } else {
-                    Ok((ChildStdio::Explicit(fd.raw()), None))
-                }
-            }
-
-            Stdio::MakePipe => {
-                let (reader, writer) = pipe::anon_pipe()?;
-                let (ours, theirs) = if readable {
-                    (writer, reader)
-                } else {
-                    (reader, writer)
-                };
-                Ok((ChildStdio::Owned(theirs.into_fd()), Some(ours)))
-            }
-
-            Stdio::Null => {
-                let mut opts = OpenOptions::new();
-                opts.read(readable);
-                opts.write(!readable);
-                let path = unsafe {
-                    CStr::from_ptr("/dev/null\0".as_ptr() as *const _)
-                };
-                let fd = File::open_c(&path, &opts)?;
-                Ok((ChildStdio::Owned(fd.into_fd()), None))
-            }
-        }
-    }
-}
-
-impl ChildStdio {
-    fn fd(&self) -> Option<c_int> {
-        match *self {
-            ChildStdio::Inherit => None,
-            ChildStdio::Explicit(fd) => Some(fd),
-            ChildStdio::Owned(ref fd) => Some(fd.raw()),
-        }
-    }
-}
-
-fn pair_to_key(key: &OsStr, value: &OsStr, saw_nul: &mut bool) -> CString {
-    let (key, value) = (key.as_bytes(), value.as_bytes());
-    let mut v = Vec::with_capacity(key.len() + value.len() + 1);
-    v.extend(key);
-    v.push(b'=');
-    v.extend(value);
-    CString::new(v).unwrap_or_else(|_e| {
-        *saw_nul = true;
-        CString::new("foo=bar").unwrap()
-    })
-}
-
-impl fmt::Debug for Command {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        write!(f, "{:?}", self.program)?;
-        for arg in &self.args {
-            write!(f, " {:?}", arg)?;
-        }
-        Ok(())
-    }
-}
-
-////////////////////////////////////////////////////////////////////////////////
-// Processes
-////////////////////////////////////////////////////////////////////////////////
-
-/// Unix exit statuses
-#[derive(PartialEq, Eq, Clone, Copy, Debug)]
-pub struct ExitStatus(c_int);
-
-impl ExitStatus {
-    fn exited(&self) -> bool {
-        unsafe { libc::WIFEXITED(self.0) }
-    }
-
-    pub fn success(&self) -> bool {
-        self.code() == Some(0)
-    }
-
-    pub fn code(&self) -> Option<i32> {
-        if self.exited() {
-            Some(unsafe { libc::WEXITSTATUS(self.0) })
-        } else {
-            None
-        }
-    }
-
-    pub fn signal(&self) -> Option<i32> {
-        if !self.exited() {
-            Some(unsafe { libc::WTERMSIG(self.0) })
-        } else {
-            None
-        }
-    }
-}
-
-impl From<c_int> for ExitStatus {
-    fn from(a: c_int) -> ExitStatus {
-        ExitStatus(a)
-    }
-}
-
-impl fmt::Display for ExitStatus {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        if let Some(code) = self.code() {
-            write!(f, "exit code: {}", code)
-        } else {
-            let signal = self.signal().unwrap();
-            write!(f, "signal: {}", signal)
-        }
-    }
-}
-
-/// The unique id of the process (this should never be negative).
-#[cfg(not(target_os = "fuchsia"))]
-pub struct Process {
-    pid: pid_t,
-    status: Option<ExitStatus>,
-}
-
-#[cfg(target_os = "fuchsia")]
-pub struct Process {
-    launchpad: *mut launchpad_t,
-    handle: mx_handle_t,
-    status: Option<ExitStatus>,
-}
-
-impl Process {
-    #[cfg(not(target_os = "fuchsia"))]
-    pub fn id(&self) -> u32 {
-        self.pid as u32
-    }
-
-    #[cfg(target_os = "fuchsia")]
-    pub fn id(&self) -> u32 {
-        0
-    }
-
-    #[cfg(not(target_os = "fuchsia"))]
-    pub fn kill(&mut self) -> io::Result<()> {
-        // If we've already waited on this process then the pid can be recycled
-        // and used for another process, and we probably shouldn't be killing
-        // random processes, so just return an error.
-        if self.status.is_some() {
-            Err(Error::new(ErrorKind::InvalidInput,
-                           "invalid argument: can't kill an exited process"))
-        } else {
-            cvt(unsafe { libc::kill(self.pid, libc::SIGKILL) }).map(|_| ())
-        }
-    }
-
-    #[cfg(target_os = "fuchsia")]
-    pub fn kill(&mut self) -> io::Result<()> {
-        use sys::magenta::*;
-
-        // If we've already waited on this process then the pid can be recycled
-        // and used for another process, and we probably shouldn't be killing
-        // random processes, so just return an error.
-        if self.status.is_some() {
-            Err(Error::new(ErrorKind::InvalidInput,
-                           "invalid argument: can't kill an exited process"))
-        } else {
-            unsafe {
-                mx_cvt(mx_handle_close(self.handle))?;
-                launchpad_destroy(self.launchpad);
-            }
-            Ok(())
-        }
-    }
-
-    #[cfg(not(target_os = "fuchsia"))]
-    pub fn wait(&mut self) -> io::Result<ExitStatus> {
-        use sys::cvt_r;
-        if let Some(status) = self.status {
-            return Ok(status)
-        }
-        let mut status = 0 as c_int;
-        cvt_r(|| unsafe { libc::waitpid(self.pid, &mut status, 0) })?;
-        self.status = Some(ExitStatus(status));
-        Ok(ExitStatus(status))
-    }
-
-    #[cfg(target_os = "fuchsia")]
-    pub fn wait(&mut self) -> io::Result<ExitStatus> {
-        use default::Default;
-        use sys::magenta::*;
-
-        if let Some(status) = self.status {
-            return Ok(status)
-        }
-
-        let mut proc_info: mx_info_process_t = Default::default();
-        let mut actual: mx_size_t = 0;
-        let mut avail: mx_size_t = 0;
-
-        unsafe {
-            mx_cvt(mx_handle_wait_one(self.handle, MX_TASK_TERMINATED,
-                                      MX_TIME_INFINITE, ptr::null_mut()))?;
-            mx_cvt(mx_object_get_info(self.handle, MX_INFO_PROCESS,
-                                      &mut proc_info as *mut _ as *mut libc::c_void,
-                                      mem::size_of::<mx_info_process_t>(), &mut actual,
-                                      &mut avail))?;
-        }
-        if actual != 1 {
-            return Err(Error::new(ErrorKind::InvalidInput,
-                                  "Failed to get exit status of process"));
-        }
-        self.status = Some(ExitStatus(proc_info.rec.return_code));
-        unsafe {
-            mx_cvt(mx_handle_close(self.handle))?;
-            launchpad_destroy(self.launchpad);
-        }
-        Ok(ExitStatus(proc_info.rec.return_code))
-    }
-}
-
-#[cfg(all(test, not(target_os = "emscripten")))]
-mod tests {
-    use super::*;
-
-    use ffi::OsStr;
-    use mem;
-    use ptr;
-    use libc;
-    use sys::cvt;
-
-    macro_rules! t {
-        ($e:expr) => {
-            match $e {
-                Ok(t) => t,
-                Err(e) => panic!("received error for `{}`: {}", stringify!($e), e),
-            }
-        }
-    }
-
-    #[cfg(not(target_os = "android"))]
-    extern {
-        #[cfg_attr(target_os = "netbsd", link_name = "__sigaddset14")]
-        fn sigaddset(set: *mut libc::sigset_t, signum: libc::c_int) -> libc::c_int;
-    }
-
-    #[cfg(target_os = "android")]
-    unsafe fn sigaddset(set: *mut libc::sigset_t, signum: libc::c_int) -> libc::c_int {
-        use slice;
-
-        let raw = slice::from_raw_parts_mut(set as *mut u8, mem::size_of::<libc::sigset_t>());
-        let bit = (signum - 1) as usize;
-        raw[bit / 8] |= 1 << (bit % 8);
-        return 0;
-    }
-
-    // See #14232 for more information, but it appears that signal delivery to a
-    // newly spawned process may just be raced in the OSX, so to prevent this
-    // test from being flaky we ignore it on OSX.
-    #[test]
-    #[cfg_attr(target_os = "macos", ignore)]
-    #[cfg_attr(target_os = "nacl", ignore)] // no signals on NaCl.
-    fn test_process_mask() {
-        unsafe {
-            // Test to make sure that a signal mask does not get inherited.
-            let mut cmd = Command::new(OsStr::new("cat"));
-
-            let mut set: libc::sigset_t = mem::uninitialized();
-            let mut old_set: libc::sigset_t = mem::uninitialized();
-            t!(cvt(libc::sigemptyset(&mut set)));
-            t!(cvt(sigaddset(&mut set, libc::SIGINT)));
-            t!(cvt(libc::pthread_sigmask(libc::SIG_SETMASK, &set, &mut old_set)));
-
-            cmd.stdin(Stdio::MakePipe);
-            cmd.stdout(Stdio::MakePipe);
-
-            let (mut cat, mut pipes) = t!(cmd.spawn(Stdio::Null, true));
-            let stdin_write = pipes.stdin.take().unwrap();
-            let stdout_read = pipes.stdout.take().unwrap();
-
-            t!(cvt(libc::pthread_sigmask(libc::SIG_SETMASK, &old_set,
-                                         ptr::null_mut())));
-
-            t!(cvt(libc::kill(cat.id() as libc::pid_t, libc::SIGINT)));
-            // We need to wait until SIGINT is definitely delivered. The
-            // easiest way is to write something to cat, and try to read it
-            // back: if SIGINT is unmasked, it'll get delivered when cat is
-            // next scheduled.
-            let _ = stdin_write.write(b"Hello");
-            drop(stdin_write);
-
-            // Either EOF or failure (EPIPE) is okay.
-            let mut buf = [0; 5];
-            if let Ok(ret) = stdout_read.read(&mut buf) {
-                assert!(ret == 0);
-            }
-
-            t!(cat.wait());
-        }
-    }
-}
diff --git a/src/libstd/sys/unix/process/mod.rs b/src/libstd/sys/unix/process/mod.rs
new file mode 100644
index 00000000000..82c3971ee40
--- /dev/null
+++ b/src/libstd/sys/unix/process/mod.rs
@@ -0,0 +1,20 @@
+// Copyright 2016 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+pub use self::process_common::{Command, ExitStatus, Stdio, StdioPipes};
+pub use self::process_inner::Process;
+
+mod process_common;
+#[cfg(not(target_os = "fuchsia"))]
+#[path = "process_unix.rs"]
+mod process_inner;
+#[cfg(target_os = "fuchsia")]
+#[path = "process_fuchsia.rs"]
+mod process_inner;
diff --git a/src/libstd/sys/unix/process/process_common.rs b/src/libstd/sys/unix/process/process_common.rs
new file mode 100644
index 00000000000..24b8b61edea
--- /dev/null
+++ b/src/libstd/sys/unix/process/process_common.rs
@@ -0,0 +1,480 @@
+// Copyright 2016 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use os::unix::prelude::*;
+
+use collections::hash_map::{HashMap, Entry};
+use env;
+use ffi::{OsString, OsStr, CString, CStr};
+use fmt;
+use io;
+use libc::{self, c_int, gid_t, uid_t, c_char};
+use ptr;
+use sys::fd::FileDesc;
+use sys::fs::{File, OpenOptions};
+use sys::pipe::{self, AnonPipe};
+
+////////////////////////////////////////////////////////////////////////////////
+// Command
+////////////////////////////////////////////////////////////////////////////////
+
+pub struct Command {
+    // Currently we try hard to ensure that the call to `.exec()` doesn't
+    // actually allocate any memory. While many platforms try to ensure that
+    // memory allocation works after a fork in a multithreaded process, it's
+    // been observed to be buggy and somewhat unreliable, so we do our best to
+    // just not do it at all!
+    //
+    // Along those lines, the `argv` and `envp` raw pointers here are exactly
+    // what's gonna get passed to `execvp`. The `argv` array starts with the
+    // `program` and ends with a NULL, and the `envp` pointer, if present, is
+    // also null-terminated.
+    //
+    // Right now we don't support removing arguments, so there's no much fancy
+    // support there, but we support adding and removing environment variables,
+    // so a side table is used to track where in the `envp` array each key is
+    // located. Whenever we add a key we update it in place if it's already
+    // present, and whenever we remove a key we update the locations of all
+    // other keys.
+    program: CString,
+    args: Vec<CString>,
+    env: Option<HashMap<OsString, (usize, CString)>>,
+    argv: Vec<*const c_char>,
+    envp: Option<Vec<*const c_char>>,
+
+    cwd: Option<CString>,
+    uid: Option<uid_t>,
+    gid: Option<gid_t>,
+    saw_nul: bool,
+    closures: Vec<Box<FnMut() -> io::Result<()> + Send + Sync>>,
+    stdin: Option<Stdio>,
+    stdout: Option<Stdio>,
+    stderr: Option<Stdio>,
+}
+
+// passed back to std::process with the pipes connected to the child, if any
+// were requested
+pub struct StdioPipes {
+    pub stdin: Option<AnonPipe>,
+    pub stdout: Option<AnonPipe>,
+    pub stderr: Option<AnonPipe>,
+}
+
+// passed to do_exec() with configuration of what the child stdio should look
+// like
+pub struct ChildPipes {
+    pub stdin: ChildStdio,
+    pub stdout: ChildStdio,
+    pub stderr: ChildStdio,
+}
+
+pub enum ChildStdio {
+    Inherit,
+    Explicit(c_int),
+    Owned(FileDesc),
+}
+
+pub enum Stdio {
+    Inherit,
+    Null,
+    MakePipe,
+    Fd(FileDesc),
+}
+
+impl Command {
+    pub fn new(program: &OsStr) -> Command {
+        let mut saw_nul = false;
+        let program = os2c(program, &mut saw_nul);
+        Command {
+            argv: vec![program.as_ptr(), ptr::null()],
+            program: program,
+            args: Vec::new(),
+            env: None,
+            envp: None,
+            cwd: None,
+            uid: None,
+            gid: None,
+            saw_nul: saw_nul,
+            closures: Vec::new(),
+            stdin: None,
+            stdout: None,
+            stderr: None,
+        }
+    }
+
+    pub fn arg(&mut self, arg: &OsStr) {
+        // Overwrite the trailing NULL pointer in `argv` and then add a new null
+        // pointer.
+        let arg = os2c(arg, &mut self.saw_nul);
+        self.argv[self.args.len() + 1] = arg.as_ptr();
+        self.argv.push(ptr::null());
+
+        // Also make sure we keep track of the owned value to schedule a
+        // destructor for this memory.
+        self.args.push(arg);
+    }
+
+    fn init_env_map(&mut self) -> (&mut HashMap<OsString, (usize, CString)>,
+                                   &mut Vec<*const c_char>) {
+        if self.env.is_none() {
+            let mut map = HashMap::new();
+            let mut envp = Vec::new();
+            for (k, v) in env::vars_os() {
+                let s = pair_to_key(&k, &v, &mut self.saw_nul);
+                envp.push(s.as_ptr());
+                map.insert(k, (envp.len() - 1, s));
+            }
+            envp.push(ptr::null());
+            self.env = Some(map);
+            self.envp = Some(envp);
+        }
+        (self.env.as_mut().unwrap(), self.envp.as_mut().unwrap())
+    }
+
+    pub fn env(&mut self, key: &OsStr, val: &OsStr) {
+        let new_key = pair_to_key(key, val, &mut self.saw_nul);
+        let (map, envp) = self.init_env_map();
+
+        // If `key` is already present then we just update `envp` in place
+        // (and store the owned value), but if it's not there we override the
+        // trailing NULL pointer, add a new NULL pointer, and store where we
+        // were located.
+        match map.entry(key.to_owned()) {
+            Entry::Occupied(mut e) => {
+                let (i, ref mut s) = *e.get_mut();
+                envp[i] = new_key.as_ptr();
+                *s = new_key;
+            }
+            Entry::Vacant(e) => {
+                let len = envp.len();
+                envp[len - 1] = new_key.as_ptr();
+                envp.push(ptr::null());
+                e.insert((len - 1, new_key));
+            }
+        }
+    }
+
+    pub fn env_remove(&mut self, key: &OsStr) {
+        let (map, envp) = self.init_env_map();
+
+        // If we actually ended up removing a key, then we need to update the
+        // position of all keys that come after us in `envp` because they're all
+        // one element sooner now.
+        if let Some((i, _)) = map.remove(key) {
+            envp.remove(i);
+
+            for (_, &mut (ref mut j, _)) in map.iter_mut() {
+                if *j >= i {
+                    *j -= 1;
+                }
+            }
+        }
+    }
+
+    pub fn env_clear(&mut self) {
+        self.env = Some(HashMap::new());
+        self.envp = Some(vec![ptr::null()]);
+    }
+
+    pub fn cwd(&mut self, dir: &OsStr) {
+        self.cwd = Some(os2c(dir, &mut self.saw_nul));
+    }
+    pub fn uid(&mut self, id: uid_t) {
+        self.uid = Some(id);
+    }
+    pub fn gid(&mut self, id: gid_t) {
+        self.gid = Some(id);
+    }
+
+    pub fn saw_nul(&self) -> bool {
+        self.saw_nul
+    }
+    pub fn get_envp(&self) -> &Option<Vec<*const c_char>> {
+        &self.envp
+    }
+    pub fn get_argv(&self) -> &Vec<*const c_char> {
+        &self.argv
+    }
+
+    #[cfg(not(target_os="fuchsia"))]
+    pub fn get_cwd(&self) -> &Option<CString> {
+        &self.cwd
+    }
+    #[cfg(not(target_os="fuchsia"))]
+    pub fn get_uid(&self) -> Option<uid_t> {
+        self.uid
+    }
+    #[cfg(not(target_os="fuchsia"))]
+    pub fn get_gid(&self) -> Option<gid_t> {
+        self.gid
+    }
+
+    pub fn get_closures(&mut self) -> &mut Vec<Box<FnMut() -> io::Result<()> + Send + Sync>> {
+        &mut self.closures
+    }
+
+    pub fn before_exec(&mut self,
+                       f: Box<FnMut() -> io::Result<()> + Send + Sync>) {
+        self.closures.push(f);
+    }
+
+    pub fn stdin(&mut self, stdin: Stdio) {
+        self.stdin = Some(stdin);
+    }
+
+    pub fn stdout(&mut self, stdout: Stdio) {
+        self.stdout = Some(stdout);
+    }
+
+    pub fn stderr(&mut self, stderr: Stdio) {
+        self.stderr = Some(stderr);
+    }
+
+    pub fn setup_io(&self, default: Stdio, needs_stdin: bool)
+                -> io::Result<(StdioPipes, ChildPipes)> {
+        let null = Stdio::Null;
+        let default_stdin = if needs_stdin {&default} else {&null};
+        let stdin = self.stdin.as_ref().unwrap_or(default_stdin);
+        let stdout = self.stdout.as_ref().unwrap_or(&default);
+        let stderr = self.stderr.as_ref().unwrap_or(&default);
+        let (their_stdin, our_stdin) = stdin.to_child_stdio(true)?;
+        let (their_stdout, our_stdout) = stdout.to_child_stdio(false)?;
+        let (their_stderr, our_stderr) = stderr.to_child_stdio(false)?;
+        let ours = StdioPipes {
+            stdin: our_stdin,
+            stdout: our_stdout,
+            stderr: our_stderr,
+        };
+        let theirs = ChildPipes {
+            stdin: their_stdin,
+            stdout: their_stdout,
+            stderr: their_stderr,
+        };
+        Ok((ours, theirs))
+    }
+}
+
+fn os2c(s: &OsStr, saw_nul: &mut bool) -> CString {
+    CString::new(s.as_bytes()).unwrap_or_else(|_e| {
+        *saw_nul = true;
+        CString::new("<string-with-nul>").unwrap()
+    })
+}
+
+impl Stdio {
+    pub fn to_child_stdio(&self, readable: bool)
+                      -> io::Result<(ChildStdio, Option<AnonPipe>)> {
+        match *self {
+            Stdio::Inherit => {
+                Ok((ChildStdio::Inherit, None))
+            },
+
+            // Make sure that the source descriptors are not an stdio
+            // descriptor, otherwise the order which we set the child's
+            // descriptors may blow away a descriptor which we are hoping to
+            // save. For example, suppose we want the child's stderr to be the
+            // parent's stdout, and the child's stdout to be the parent's
+            // stderr. No matter which we dup first, the second will get
+            // overwritten prematurely.
+            Stdio::Fd(ref fd) => {
+                if fd.raw() >= 0 && fd.raw() <= libc::STDERR_FILENO {
+                    Ok((ChildStdio::Owned(fd.duplicate()?), None))
+                } else {
+                    Ok((ChildStdio::Explicit(fd.raw()), None))
+                }
+            }
+
+            Stdio::MakePipe => {
+                let (reader, writer) = pipe::anon_pipe()?;
+                let (ours, theirs) = if readable {
+                    (writer, reader)
+                } else {
+                    (reader, writer)
+                };
+                Ok((ChildStdio::Owned(theirs.into_fd()), Some(ours)))
+            }
+
+            Stdio::Null => {
+                let mut opts = OpenOptions::new();
+                opts.read(readable);
+                opts.write(!readable);
+                let path = unsafe {
+                    CStr::from_ptr("/dev/null\0".as_ptr() as *const _)
+                };
+                let fd = File::open_c(&path, &opts)?;
+                Ok((ChildStdio::Owned(fd.into_fd()), None))
+            }
+        }
+    }
+}
+
+impl ChildStdio {
+    pub fn fd(&self) -> Option<c_int> {
+        match *self {
+            ChildStdio::Inherit => None,
+            ChildStdio::Explicit(fd) => Some(fd),
+            ChildStdio::Owned(ref fd) => Some(fd.raw()),
+        }
+    }
+}
+
+fn pair_to_key(key: &OsStr, value: &OsStr, saw_nul: &mut bool) -> CString {
+    let (key, value) = (key.as_bytes(), value.as_bytes());
+    let mut v = Vec::with_capacity(key.len() + value.len() + 1);
+    v.extend(key);
+    v.push(b'=');
+    v.extend(value);
+    CString::new(v).unwrap_or_else(|_e| {
+        *saw_nul = true;
+        CString::new("foo=bar").unwrap()
+    })
+}
+
+impl fmt::Debug for Command {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "{:?}", self.program)?;
+        for arg in &self.args {
+            write!(f, " {:?}", arg)?;
+        }
+        Ok(())
+    }
+}
+
+/// Unix exit statuses
+#[derive(PartialEq, Eq, Clone, Copy, Debug)]
+pub struct ExitStatus(c_int);
+
+impl ExitStatus {
+    pub fn new(status: c_int) -> ExitStatus {
+        ExitStatus(status)
+    }
+
+    fn exited(&self) -> bool {
+        unsafe { libc::WIFEXITED(self.0) }
+    }
+
+    pub fn success(&self) -> bool {
+        self.code() == Some(0)
+    }
+
+    pub fn code(&self) -> Option<i32> {
+        if self.exited() {
+            Some(unsafe { libc::WEXITSTATUS(self.0) })
+        } else {
+            None
+        }
+    }
+
+    pub fn signal(&self) -> Option<i32> {
+        if !self.exited() {
+            Some(unsafe { libc::WTERMSIG(self.0) })
+        } else {
+            None
+        }
+    }
+}
+
+impl From<c_int> for ExitStatus {
+    fn from(a: c_int) -> ExitStatus {
+        ExitStatus(a)
+    }
+}
+
+impl fmt::Display for ExitStatus {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        if let Some(code) = self.code() {
+            write!(f, "exit code: {}", code)
+        } else {
+            let signal = self.signal().unwrap();
+            write!(f, "signal: {}", signal)
+        }
+    }
+}
+
+#[cfg(all(test, not(target_os = "emscripten")))]
+mod tests {
+    use super::*;
+
+    use ffi::OsStr;
+    use mem;
+    use ptr;
+    use libc;
+    use sys::cvt;
+
+    macro_rules! t {
+        ($e:expr) => {
+            match $e {
+                Ok(t) => t,
+                Err(e) => panic!("received error for `{}`: {}", stringify!($e), e),
+            }
+        }
+    }
+
+    #[cfg(not(target_os = "android"))]
+    extern {
+        #[cfg_attr(target_os = "netbsd", link_name = "__sigaddset14")]
+        fn sigaddset(set: *mut libc::sigset_t, signum: libc::c_int) -> libc::c_int;
+    }
+
+    #[cfg(target_os = "android")]
+    unsafe fn sigaddset(set: *mut libc::sigset_t, signum: libc::c_int) -> libc::c_int {
+        use slice;
+
+        let raw = slice::from_raw_parts_mut(set as *mut u8, mem::size_of::<libc::sigset_t>());
+        let bit = (signum - 1) as usize;
+        raw[bit / 8] |= 1 << (bit % 8);
+        return 0;
+    }
+
+    // See #14232 for more information, but it appears that signal delivery to a
+    // newly spawned process may just be raced in the OSX, so to prevent this
+    // test from being flaky we ignore it on OSX.
+    #[test]
+    #[cfg_attr(target_os = "macos", ignore)]
+    #[cfg_attr(target_os = "nacl", ignore)] // no signals on NaCl.
+    fn test_process_mask() {
+        unsafe {
+            // Test to make sure that a signal mask does not get inherited.
+            let mut cmd = Command::new(OsStr::new("cat"));
+
+            let mut set: libc::sigset_t = mem::uninitialized();
+            let mut old_set: libc::sigset_t = mem::uninitialized();
+            t!(cvt(libc::sigemptyset(&mut set)));
+            t!(cvt(sigaddset(&mut set, libc::SIGINT)));
+            t!(cvt(libc::pthread_sigmask(libc::SIG_SETMASK, &set, &mut old_set)));
+
+            cmd.stdin(Stdio::MakePipe);
+            cmd.stdout(Stdio::MakePipe);
+
+            let (mut cat, mut pipes) = t!(cmd.spawn(Stdio::Null, true));
+            let stdin_write = pipes.stdin.take().unwrap();
+            let stdout_read = pipes.stdout.take().unwrap();
+
+            t!(cvt(libc::pthread_sigmask(libc::SIG_SETMASK, &old_set,
+                                         ptr::null_mut())));
+
+            t!(cvt(libc::kill(cat.id() as libc::pid_t, libc::SIGINT)));
+            // We need to wait until SIGINT is definitely delivered. The
+            // easiest way is to write something to cat, and try to read it
+            // back: if SIGINT is unmasked, it'll get delivered when cat is
+            // next scheduled.
+            let _ = stdin_write.write(b"Hello");
+            drop(stdin_write);
+
+            // Either EOF or failure (EPIPE) is okay.
+            let mut buf = [0; 5];
+            if let Ok(ret) = stdout_read.read(&mut buf) {
+                assert!(ret == 0);
+            }
+
+            t!(cat.wait());
+        }
+    }
+}
diff --git a/src/libstd/sys/unix/process/process_fuchsia.rs b/src/libstd/sys/unix/process/process_fuchsia.rs
new file mode 100644
index 00000000000..30e5555df69
--- /dev/null
+++ b/src/libstd/sys/unix/process/process_fuchsia.rs
@@ -0,0 +1,190 @@
+// Copyright 2016 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use io;
+use libc;
+use mem;
+use ptr;
+
+use sys::mx_cvt;
+use sys::magenta::{launchpad_t, mx_handle_t};
+use sys::process::process_common::*;
+
+////////////////////////////////////////////////////////////////////////////////
+// Command
+////////////////////////////////////////////////////////////////////////////////
+
+impl Command {
+    pub fn spawn(&mut self, default: Stdio, needs_stdin: bool)
+                 -> io::Result<(Process, StdioPipes)> {
+        if self.saw_nul() {
+            return Err(io::Error::new(io::ErrorKind::InvalidInput,
+                                      "nul byte found in provided data"));
+        }
+
+        let (ours, theirs) = self.setup_io(default, needs_stdin)?;
+
+        let (launchpad, process_handle) = unsafe { self.do_exec(theirs)? };
+
+        Ok((Process { launchpad: launchpad, handle: process_handle, status: None }, ours))
+    }
+
+    pub fn exec(&mut self, default: Stdio) -> io::Error {
+        if self.saw_nul() {
+            return io::Error::new(io::ErrorKind::InvalidInput,
+                                  "nul byte found in provided data")
+        }
+
+        match self.setup_io(default, true) {
+            Ok((_, _)) => {
+                // FIXME: This is tough because we don't support the exec syscalls
+                unimplemented!();
+            },
+            Err(e) => e,
+        }
+    }
+
+    unsafe fn do_exec(&mut self, stdio: ChildPipes)
+                      -> io::Result<(*mut launchpad_t, mx_handle_t)> {
+        use sys::magenta::*;
+
+        let job_handle = mxio_get_startup_handle(mx_hnd_info(MX_HND_TYPE_JOB, 0));
+        let envp = match *self.get_envp() {
+            Some(ref envp) => envp.as_ptr(),
+            None => ptr::null(),
+        };
+
+        // To make sure launchpad_destroy gets called on the launchpad if this function fails
+        struct LaunchpadDestructor(*mut launchpad_t);
+        impl Drop for LaunchpadDestructor {
+            fn drop(&mut self) { unsafe { launchpad_destroy(self.0); } }
+        }
+
+        let mut launchpad: *mut launchpad_t = ptr::null_mut();
+        let launchpad_destructor = LaunchpadDestructor(launchpad);
+
+        // Duplicate the job handle
+        let mut job_copy: mx_handle_t = MX_HANDLE_INVALID;
+        mx_cvt(mx_handle_duplicate(job_handle, MX_RIGHT_SAME_RIGHTS,
+                                   &mut job_copy as *mut mx_handle_t))?;
+        // Create a launchpad
+        mx_cvt(launchpad_create(job_copy, self.get_argv()[0],
+                                &mut launchpad as *mut *mut launchpad_t))?;
+        // Set the process argv
+        mx_cvt(launchpad_arguments(launchpad, self.get_argv().len() as i32 - 1,
+                                   self.get_argv().as_ptr()))?;
+        // Setup the environment vars
+        mx_cvt(launchpad_environ(launchpad, envp))?;
+        mx_cvt(launchpad_add_vdso_vmo(launchpad))?;
+        mx_cvt(launchpad_clone_mxio_root(launchpad))?;
+        // Load the executable
+        mx_cvt(launchpad_elf_load(launchpad, launchpad_vmo_from_file(self.get_argv()[0])))?;
+        mx_cvt(launchpad_load_vdso(launchpad, MX_HANDLE_INVALID))?;
+        mx_cvt(launchpad_clone_mxio_cwd(launchpad))?;
+
+        // Clone stdin, stdout, and stderr
+        if let Some(fd) = stdio.stdin.fd() {
+            launchpad_transfer_fd(launchpad, fd, 0);
+        } else {
+            launchpad_clone_fd(launchpad, 0, 0);
+        }
+        if let Some(fd) = stdio.stdout.fd() {
+            launchpad_transfer_fd(launchpad, fd, 1);
+        } else {
+            launchpad_clone_fd(launchpad, 1, 1);
+        }
+        if let Some(fd) = stdio.stderr.fd() {
+            launchpad_transfer_fd(launchpad, fd, 2);
+        } else {
+            launchpad_clone_fd(launchpad, 2, 2);
+        }
+
+        // We don't want FileDesc::drop to be called on any stdio. It would close their fds. The
+        // fds will be closed once the child process finishes.
+        mem::forget(stdio);
+
+        for callback in self.get_closures().iter_mut() {
+            callback()?;
+        }
+
+        let process_handle = mx_cvt(launchpad_start(launchpad))?;
+
+        // Successfully started the launchpad, so launchpad_destroy shouldn't get called
+        mem::forget(launchpad_destructor);
+
+        Ok((launchpad, process_handle))
+    }
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Processes
+////////////////////////////////////////////////////////////////////////////////
+
+pub struct Process {
+    launchpad: *mut launchpad_t,
+    handle: mx_handle_t,
+    status: Option<ExitStatus>,
+}
+
+impl Process {
+    pub fn id(&self) -> u32 {
+        self.handle as u32
+    }
+
+    pub fn kill(&mut self) -> io::Result<()> {
+        use sys::magenta::*;
+
+        // If we've already waited on this process then the pid can be recycled
+        // and used for another process, and we probably shouldn't be killing
+        // random processes, so just return an error.
+        if self.status.is_some() {
+            Err(io::Error::new(io::ErrorKind::InvalidInput,
+                           "invalid argument: can't kill an exited process"))
+        } else {
+            unsafe {
+                mx_cvt(mx_handle_close(self.handle))?;
+                launchpad_destroy(self.launchpad);
+            }
+            Ok(())
+        }
+    }
+
+    pub fn wait(&mut self) -> io::Result<ExitStatus> {
+        use default::Default;
+        use sys::magenta::*;
+
+        if let Some(status) = self.status {
+            return Ok(status)
+        }
+
+        let mut proc_info: mx_info_process_t = Default::default();
+        let mut actual: mx_size_t = 0;
+        let mut avail: mx_size_t = 0;
+
+        unsafe {
+            mx_cvt(mx_handle_wait_one(self.handle, MX_TASK_TERMINATED,
+                                      MX_TIME_INFINITE, ptr::null_mut()))?;
+            mx_cvt(mx_object_get_info(self.handle, MX_INFO_PROCESS,
+                                      &mut proc_info as *mut _ as *mut libc::c_void,
+                                      mem::size_of::<mx_info_process_t>(), &mut actual,
+                                      &mut avail))?;
+        }
+        if actual != 1 {
+            return Err(io::Error::new(io::ErrorKind::InvalidInput,
+                                  "Failed to get exit status of process"));
+        }
+        self.status = Some(ExitStatus::new(proc_info.rec.return_code));
+        unsafe {
+            mx_cvt(mx_handle_close(self.handle))?;
+            launchpad_destroy(self.launchpad);
+        }
+        Ok(ExitStatus::new(proc_info.rec.return_code))
+    }
+}
diff --git a/src/libstd/sys/unix/process/process_unix.rs b/src/libstd/sys/unix/process/process_unix.rs
new file mode 100644
index 00000000000..aa426722025
--- /dev/null
+++ b/src/libstd/sys/unix/process/process_unix.rs
@@ -0,0 +1,250 @@
+// Copyright 2014-2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use io::{self, Error, ErrorKind};
+use libc::{self, c_int, gid_t, pid_t, uid_t};
+use mem;
+use ptr;
+
+use sys::cvt;
+use sys::process::process_common::*;
+
+////////////////////////////////////////////////////////////////////////////////
+// Command
+////////////////////////////////////////////////////////////////////////////////
+
+impl Command {
+    pub fn spawn(&mut self, default: Stdio, needs_stdin: bool)
+                 -> io::Result<(Process, StdioPipes)> {
+        use sys;
+
+        const CLOEXEC_MSG_FOOTER: &'static [u8] = b"NOEX";
+
+        if self.saw_nul() {
+            return Err(io::Error::new(ErrorKind::InvalidInput,
+                                      "nul byte found in provided data"));
+        }
+
+        let (ours, theirs) = self.setup_io(default, needs_stdin)?;
+        let (input, output) = sys::pipe::anon_pipe()?;
+
+        let pid = unsafe {
+            match cvt(libc::fork())? {
+                0 => {
+                    drop(input);
+                    let err = self.do_exec(theirs);
+                    let errno = err.raw_os_error().unwrap_or(libc::EINVAL) as u32;
+                    let bytes = [
+                        (errno >> 24) as u8,
+                        (errno >> 16) as u8,
+                        (errno >>  8) as u8,
+                        (errno >>  0) as u8,
+                        CLOEXEC_MSG_FOOTER[0], CLOEXEC_MSG_FOOTER[1],
+                        CLOEXEC_MSG_FOOTER[2], CLOEXEC_MSG_FOOTER[3]
+                    ];
+                    // pipe I/O up to PIPE_BUF bytes should be atomic, and then
+                    // we want to be sure we *don't* run at_exit destructors as
+                    // we're being torn down regardless
+                    assert!(output.write(&bytes).is_ok());
+                    libc::_exit(1)
+                }
+                n => n,
+            }
+        };
+
+        let mut p = Process { pid: pid, status: None };
+        drop(output);
+        let mut bytes = [0; 8];
+
+        // loop to handle EINTR
+        loop {
+            match input.read(&mut bytes) {
+                Ok(0) => return Ok((p, ours)),
+                Ok(8) => {
+                    assert!(combine(CLOEXEC_MSG_FOOTER) == combine(&bytes[4.. 8]),
+                            "Validation on the CLOEXEC pipe failed: {:?}", bytes);
+                    let errno = combine(&bytes[0.. 4]);
+                    assert!(p.wait().is_ok(),
+                            "wait() should either return Ok or panic");
+                    return Err(Error::from_raw_os_error(errno))
+                }
+                Err(ref e) if e.kind() == ErrorKind::Interrupted => {}
+                Err(e) => {
+                    assert!(p.wait().is_ok(),
+                            "wait() should either return Ok or panic");
+                    panic!("the CLOEXEC pipe failed: {:?}", e)
+                },
+                Ok(..) => { // pipe I/O up to PIPE_BUF bytes should be atomic
+                    assert!(p.wait().is_ok(),
+                            "wait() should either return Ok or panic");
+                    panic!("short read on the CLOEXEC pipe")
+                }
+            }
+        }
+
+        fn combine(arr: &[u8]) -> i32 {
+            let a = arr[0] as u32;
+            let b = arr[1] as u32;
+            let c = arr[2] as u32;
+            let d = arr[3] as u32;
+
+            ((a << 24) | (b << 16) | (c << 8) | (d << 0)) as i32
+        }
+    }
+
+    pub fn exec(&mut self, default: Stdio) -> io::Error {
+        if self.saw_nul() {
+            return io::Error::new(ErrorKind::InvalidInput,
+                                  "nul byte found in provided data")
+        }
+
+        match self.setup_io(default, true) {
+            Ok((_, theirs)) => unsafe { self.do_exec(theirs) },
+            Err(e) => e,
+        }
+    }
+
+    // And at this point we've reached a special time in the life of the
+    // child. The child must now be considered hamstrung and unable to
+    // do anything other than syscalls really. Consider the following
+    // scenario:
+    //
+    //      1. Thread A of process 1 grabs the malloc() mutex
+    //      2. Thread B of process 1 forks(), creating thread C
+    //      3. Thread C of process 2 then attempts to malloc()
+    //      4. The memory of process 2 is the same as the memory of
+    //         process 1, so the mutex is locked.
+    //
+    // This situation looks a lot like deadlock, right? It turns out
+    // that this is what pthread_atfork() takes care of, which is
+    // presumably implemented across platforms. The first thing that
+    // threads to *before* forking is to do things like grab the malloc
+    // mutex, and then after the fork they unlock it.
+    //
+    // Despite this information, libnative's spawn has been witnessed to
+    // deadlock on both OSX and FreeBSD. I'm not entirely sure why, but
+    // all collected backtraces point at malloc/free traffic in the
+    // child spawned process.
+    //
+    // For this reason, the block of code below should contain 0
+    // invocations of either malloc of free (or their related friends).
+    //
+    // As an example of not having malloc/free traffic, we don't close
+    // this file descriptor by dropping the FileDesc (which contains an
+    // allocation). Instead we just close it manually. This will never
+    // have the drop glue anyway because this code never returns (the
+    // child will either exec() or invoke libc::exit)
+    unsafe fn do_exec(&mut self, stdio: ChildPipes) -> io::Error {
+        use sys::{self, cvt_r};
+
+        macro_rules! t {
+            ($e:expr) => (match $e {
+                Ok(e) => e,
+                Err(e) => return e,
+            })
+        }
+
+        if let Some(fd) = stdio.stdin.fd() {
+            t!(cvt_r(|| libc::dup2(fd, libc::STDIN_FILENO)));
+        }
+        if let Some(fd) = stdio.stdout.fd() {
+            t!(cvt_r(|| libc::dup2(fd, libc::STDOUT_FILENO)));
+        }
+        if let Some(fd) = stdio.stderr.fd() {
+            t!(cvt_r(|| libc::dup2(fd, libc::STDERR_FILENO)));
+        }
+
+        if let Some(u) = self.get_gid() {
+            t!(cvt(libc::setgid(u as gid_t)));
+        }
+        if let Some(u) = self.get_uid() {
+            // When dropping privileges from root, the `setgroups` call
+            // will remove any extraneous groups. If we don't call this,
+            // then even though our uid has dropped, we may still have
+            // groups that enable us to do super-user things. This will
+            // fail if we aren't root, so don't bother checking the
+            // return value, this is just done as an optimistic
+            // privilege dropping function.
+            let _ = libc::setgroups(0, ptr::null());
+
+            t!(cvt(libc::setuid(u as uid_t)));
+        }
+        if let Some(ref cwd) = *self.get_cwd() {
+            t!(cvt(libc::chdir(cwd.as_ptr())));
+        }
+        if let Some(ref envp) = *self.get_envp() {
+            *sys::os::environ() = envp.as_ptr();
+        }
+
+        // NaCl has no signal support.
+        if cfg!(not(any(target_os = "nacl", target_os = "emscripten"))) {
+            // Reset signal handling so the child process starts in a
+            // standardized state. libstd ignores SIGPIPE, and signal-handling
+            // libraries often set a mask. Child processes inherit ignored
+            // signals and the signal mask from their parent, but most
+            // UNIX programs do not reset these things on their own, so we
+            // need to clean things up now to avoid confusing the program
+            // we're about to run.
+            let mut set: libc::sigset_t = mem::uninitialized();
+            t!(cvt(libc::sigemptyset(&mut set)));
+            t!(cvt(libc::pthread_sigmask(libc::SIG_SETMASK, &set,
+                                         ptr::null_mut())));
+            let ret = sys::signal(libc::SIGPIPE, libc::SIG_DFL);
+            if ret == libc::SIG_ERR {
+                return io::Error::last_os_error()
+            }
+        }
+
+        for callback in self.get_closures().iter_mut() {
+            t!(callback());
+        }
+
+        libc::execvp(self.get_argv()[0], self.get_argv().as_ptr());
+        io::Error::last_os_error()
+    }
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Processes
+////////////////////////////////////////////////////////////////////////////////
+
+/// The unique id of the process (this should never be negative).
+pub struct Process {
+    pid: pid_t,
+    status: Option<ExitStatus>,
+}
+
+impl Process {
+    pub fn id(&self) -> u32 {
+        self.pid as u32
+    }
+
+    pub fn kill(&mut self) -> io::Result<()> {
+        // If we've already waited on this process then the pid can be recycled
+        // and used for another process, and we probably shouldn't be killing
+        // random processes, so just return an error.
+        if self.status.is_some() {
+            Err(Error::new(ErrorKind::InvalidInput,
+                           "invalid argument: can't kill an exited process"))
+        } else {
+            cvt(unsafe { libc::kill(self.pid, libc::SIGKILL) }).map(|_| ())
+        }
+    }
+    pub fn wait(&mut self) -> io::Result<ExitStatus> {
+        use sys::cvt_r;
+        if let Some(status) = self.status {
+            return Ok(status)
+        }
+        let mut status = 0 as c_int;
+        cvt_r(|| unsafe { libc::waitpid(self.pid, &mut status, 0) })?;
+        self.status = Some(ExitStatus::new(status));
+        Ok(ExitStatus::new(status))
+    }
+}