Auto merge of #37936 - tedsta:fuchsia_std_process, r=alexcrichton

Fuchsia support for std::process via liblaunchpad.

Now we can launch processes on Fuchsia via the Rust standard library! ... Mostly.

Right now, ~5% of the time, reading the stdout/stderr off the pipes will fail. Some Magenta kernel people think it's probably a bug in Magenta's pipes. I wrote a unit test that demonstrates the issue in C, which I was told will expedite a fix. https://fuchsia-review.googlesource.com/#/c/15628/

Hopefully this can get merged once the issue is fixed :)

@raphlinus

8 files changed, 689 insertions, 238 deletions

diff --git a/src/libstd/build.rs b/src/libstd/build.rs
index 72cd6e4830b..1087d1f2447 100644
--- a/src/libstd/build.rs
+++ b/src/libstd/build.rs
@@ -60,6 +60,8 @@ fn main() {
         println!("cargo:rustc-link-lib=shell32");
     } else if target.contains("fuchsia") {
         println!("cargo:rustc-link-lib=magenta");
+        println!("cargo:rustc-link-lib=mxio");
+        println!("cargo:rustc-link-lib=launchpad"); // for std::process
     }
 }
 
diff --git a/src/libstd/sys/unix/fd.rs b/src/libstd/sys/unix/fd.rs
index 41bb96fed16..61eb60da486 100644
--- a/src/libstd/sys/unix/fd.rs
+++ b/src/libstd/sys/unix/fd.rs
@@ -110,6 +110,7 @@ impl FileDesc {
     #[cfg(not(any(target_env = "newlib",
                   target_os = "solaris",
                   target_os = "emscripten",
+                  target_os = "fuchsia",
                   target_os = "haiku")))]
     pub fn set_cloexec(&self) -> io::Result<()> {
         unsafe {
@@ -120,6 +121,7 @@ impl FileDesc {
     #[cfg(any(target_env = "newlib",
               target_os = "solaris",
               target_os = "emscripten",
+              target_os = "fuchsia",
               target_os = "haiku"))]
     pub fn set_cloexec(&self) -> io::Result<()> {
         unsafe {
diff --git a/src/libstd/sys/unix/pipe.rs b/src/libstd/sys/unix/pipe.rs
index ffe8032e460..a8ed415b7f4 100644
--- a/src/libstd/sys/unix/pipe.rs
+++ b/src/libstd/sys/unix/pipe.rs
@@ -77,6 +77,7 @@ pub fn read2(p1: AnonPipe,
              v1: &mut Vec<u8>,
              p2: AnonPipe,
              v2: &mut Vec<u8>) -> io::Result<()> {
+
     // Set both pipes into nonblocking mode as we're gonna be reading from both
     // in the `select` loop below, and we wouldn't want one to block the other!
     let p1 = p1.into_fd();
diff --git a/src/libstd/sys/unix/process/magenta.rs b/src/libstd/sys/unix/process/magenta.rs
new file mode 100644
index 00000000000..319fbce35cd
--- /dev/null
+++ b/src/libstd/sys/unix/process/magenta.rs
@@ -0,0 +1,191 @@
+// 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.
+
+#![allow(non_camel_case_types)]
+
+use convert::TryInto;
+use io;
+use os::raw::c_char;
+use u64;
+
+use libc::{c_int, c_void};
+
+pub type mx_handle_t = i32;
+pub type mx_vaddr_t = usize;
+pub type mx_rights_t = u32;
+pub type mx_status_t = i32;
+
+pub type mx_size_t = usize;
+pub type mx_ssize_t = isize;
+
+pub const MX_HANDLE_INVALID: mx_handle_t = 0;
+
+pub type mx_time_t = u64;
+pub const MX_TIME_INFINITE : mx_time_t = u64::MAX;
+
+pub type mx_signals_t = u32;
+
+pub const MX_OBJECT_SIGNAL_3         : mx_signals_t = 1 << 3;
+
+pub const MX_TASK_TERMINATED        : mx_signals_t = MX_OBJECT_SIGNAL_3;
+
+pub const MX_RIGHT_SAME_RIGHTS  : mx_rights_t = 1 << 31;
+
+pub type mx_object_info_topic_t = u32;
+
+pub const MX_INFO_PROCESS         : mx_object_info_topic_t = 3;
+
+pub const MX_HND_TYPE_JOB: u32 = 6;
+
+pub fn mx_cvt<T>(t: T) -> io::Result<T> where T: TryInto<mx_status_t>+Copy {
+    if let Ok(status) = TryInto::try_into(t) {
+        if status < 0 {
+            Err(io::Error::from_raw_os_error(status))
+        } else {
+            Ok(t)
+        }
+    } else {
+        Err(io::Error::last_os_error())
+    }
+}
+
+// Safe wrapper around mx_handle_t
+pub struct Handle {
+    raw: mx_handle_t,
+}
+
+impl Handle {
+    pub fn new(raw: mx_handle_t) -> Handle {
+        Handle {
+            raw: raw,
+        }
+    }
+
+    pub fn raw(&self) -> mx_handle_t {
+        self.raw
+    }
+}
+
+impl Drop for Handle {
+    fn drop(&mut self) {
+        unsafe { mx_cvt(mx_handle_close(self.raw)).expect("Failed to close mx_handle_t"); }
+    }
+}
+
+// Common MX_INFO header
+#[derive(Default)]
+#[repr(C)]
+pub struct mx_info_header_t {
+    pub topic: u32,              // identifies the info struct
+    pub avail_topic_size: u16,   // “native” size of the struct
+    pub topic_size: u16,         // size of the returned struct (<=topic_size)
+    pub avail_count: u32,        // number of records the kernel has
+    pub count: u32,              // number of records returned (limited by buffer size)
+}
+
+#[derive(Default)]
+#[repr(C)]
+pub struct mx_record_process_t {
+    pub return_code: c_int,
+}
+
+// Returned for topic MX_INFO_PROCESS
+#[derive(Default)]
+#[repr(C)]
+pub struct mx_info_process_t {
+    pub hdr: mx_info_header_t,
+    pub rec: mx_record_process_t,
+}
+
+extern {
+    pub fn mx_task_kill(handle: mx_handle_t) -> mx_status_t;
+
+    pub fn mx_handle_close(handle: mx_handle_t) -> mx_status_t;
+
+    pub fn mx_handle_duplicate(handle: mx_handle_t, rights: mx_rights_t,
+                               out: *const mx_handle_t) -> mx_handle_t;
+
+    pub fn mx_handle_wait_one(handle: mx_handle_t, signals: mx_signals_t, timeout: mx_time_t,
+                              pending: *mut mx_signals_t) -> mx_status_t;
+
+    pub fn mx_object_get_info(handle: mx_handle_t, topic: u32, buffer: *mut c_void,
+                              buffer_size: mx_size_t, actual_size: *mut mx_size_t,
+                              avail: *mut mx_size_t) -> mx_status_t;
+}
+
+// Handle Info entries associate a type and optional
+// argument with each handle included in the process
+// arguments message.
+pub fn mx_hnd_info(hnd_type: u32, arg: u32) -> u32 {
+    (hnd_type & 0xFFFF) | ((arg & 0xFFFF) << 16)
+}
+
+extern {
+    pub fn mxio_get_startup_handle(id: u32) -> mx_handle_t;
+}
+
+// From `enum special_handles` in system/ulib/launchpad/launchpad.c
+#[allow(unused)] pub const HND_LOADER_SVC: usize = 0;
+// HND_EXEC_VMO = 1
+#[allow(unused)] pub const HND_SPECIAL_COUNT: usize = 2;
+
+#[repr(C)]
+pub struct launchpad_t {
+    argc: u32,
+    envc: u32,
+    args: *const c_char,
+    args_len: usize,
+    env: *const c_char,
+    env_len: usize,
+
+    handles: *mut mx_handle_t,
+    handles_info: *mut u32,
+    handle_count: usize,
+    handle_alloc: usize,
+
+    entry: mx_vaddr_t,
+    base: mx_vaddr_t,
+    vdso_base: mx_vaddr_t,
+
+    stack_size: usize,
+
+    special_handles: [mx_handle_t; HND_SPECIAL_COUNT],
+    loader_message: bool,
+}
+
+extern {
+    pub fn launchpad_create(job: mx_handle_t, name: *const c_char,
+                            lp: *mut *mut launchpad_t) -> mx_status_t;
+
+    pub fn launchpad_start(lp: *mut launchpad_t) -> mx_status_t;
+
+    pub fn launchpad_destroy(lp: *mut launchpad_t);
+
+    pub fn launchpad_arguments(lp: *mut launchpad_t, argc: c_int,
+                               argv: *const *const c_char) -> mx_status_t;
+
+    pub fn launchpad_environ(lp: *mut launchpad_t, envp: *const *const c_char) -> mx_status_t;
+
+    pub fn launchpad_clone_mxio_root(lp: *mut launchpad_t) -> mx_status_t;
+
+    pub fn launchpad_clone_mxio_cwd(lp: *mut launchpad_t) -> mx_status_t;
+
+    pub fn launchpad_clone_fd(lp: *mut launchpad_t, fd: c_int, target_fd: c_int) -> mx_status_t;
+
+    pub fn launchpad_transfer_fd(lp: *mut launchpad_t, fd: c_int, target_fd: c_int) -> mx_status_t;
+
+    pub fn launchpad_elf_load(lp: *mut launchpad_t, vmo: mx_handle_t) -> mx_status_t;
+
+    pub fn launchpad_add_vdso_vmo(lp: *mut launchpad_t) -> mx_status_t;
+
+    pub fn launchpad_load_vdso(lp: *mut launchpad_t, vmo: mx_handle_t) -> mx_status_t;
+
+    pub fn launchpad_vmo_from_file(filename: *const c_char) -> mx_handle_t;
+}
diff --git a/src/libstd/sys/unix/process/mod.rs b/src/libstd/sys/unix/process/mod.rs
new file mode 100644
index 00000000000..b50384d8eee
--- /dev/null
+++ b/src/libstd/sys/unix/process/mod.rs
@@ -0,0 +1,22 @@
+// 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;
+#[cfg(target_os = "fuchsia")]
+mod magenta;
diff --git a/src/libstd/sys/unix/process.rs b/src/libstd/sys/unix/process/process_common.rs
index dafc11d9cc8..3497b266340 100644
--- a/src/libstd/sys/unix/process.rs
+++ b/src/libstd/sys/unix/process/process_common.rs
@@ -1,4 +1,4 @@
-// Copyright 2014-2015 The Rust Project Developers. See the COPYRIGHT
+// 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.
 //
@@ -14,14 +14,12 @@ use collections::hash_map::{HashMap, Entry};
 use env;
 use ffi::{OsString, OsStr, CString, CStr};
 use fmt;
-use io::{self, Error, ErrorKind};
-use libc::{self, pid_t, c_int, gid_t, uid_t, c_char};
-use mem;
+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};
-use sys::{self, cvt, cvt_r};
 
 ////////////////////////////////////////////////////////////////////////////////
 // Command
@@ -71,13 +69,13 @@ pub struct StdioPipes {
 
 // passed to do_exec() with configuration of what the child stdio should look
 // like
-struct ChildPipes {
-    stdin: ChildStdio,
-    stdout: ChildStdio,
-    stderr: ChildStdio,
+pub struct ChildPipes {
+    pub stdin: ChildStdio,
+    pub stdout: ChildStdio,
+    pub stderr: ChildStdio,
 }
 
-enum ChildStdio {
+pub enum ChildStdio {
     Inherit,
     Explicit(c_int),
     Owned(FileDesc),
@@ -195,6 +193,33 @@ impl Command {
         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
+    }
+
+    #[allow(dead_code)]
+    pub fn get_cwd(&self) -> &Option<CString> {
+        &self.cwd
+    }
+    #[allow(dead_code)]
+    pub fn get_uid(&self) -> Option<uid_t> {
+        self.uid
+    }
+    #[allow(dead_code)]
+    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);
@@ -203,200 +228,16 @@ impl Command {
     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 spawn(&mut self, default: Stdio, needs_stdin: bool)
-                 -> io::Result<(Process, StdioPipes)> {
-        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 {
-        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()
-    }
-
-
-    fn setup_io(&self, default: Stdio, needs_stdin: bool)
+    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};
@@ -428,10 +269,12 @@ fn os2c(s: &OsStr, saw_nul: &mut bool) -> CString {
 }
 
 impl Stdio {
-    fn to_child_stdio(&self, readable: bool)
+    pub fn to_child_stdio(&self, readable: bool)
                       -> io::Result<(ChildStdio, Option<AnonPipe>)> {
         match *self {
-            Stdio::Inherit => Ok((ChildStdio::Inherit, None)),
+            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
@@ -473,7 +316,7 @@ impl Stdio {
 }
 
 impl ChildStdio {
-    fn fd(&self) -> Option<c_int> {
+    pub fn fd(&self) -> Option<c_int> {
         match *self {
             ChildStdio::Inherit => None,
             ChildStdio::Explicit(fd) => Some(fd),
@@ -504,15 +347,15 @@ impl fmt::Debug for Command {
     }
 }
 
-////////////////////////////////////////////////////////////////////////////////
-// Processes
-////////////////////////////////////////////////////////////////////////////////
-
 /// 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) }
     }
@@ -555,40 +398,6 @@ impl fmt::Display for ExitStatus {
     }
 }
 
-/// 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> {
-        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(all(test, not(target_os = "emscripten")))]
 mod tests {
     use super::*;
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..f0a42b12799
--- /dev/null
+++ b/src/libstd/sys/unix/process/process_fuchsia.rs
@@ -0,0 +1,174 @@
+// 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::process::magenta::{Handle, 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: Handle::new(process_handle) }, 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::process::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))?;
+        // Create a launchpad
+        mx_cvt(launchpad_create(job_copy, self.get_argv()[0], &mut launchpad))?;
+        // 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
+        mem::forget(launchpad_destructor);
+
+        Ok((launchpad, process_handle))
+    }
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Processes
+////////////////////////////////////////////////////////////////////////////////
+
+pub struct Process {
+    launchpad: *mut launchpad_t,
+    handle: Handle,
+}
+
+impl Process {
+    pub fn id(&self) -> u32 {
+        self.handle.raw() as u32
+    }
+
+    pub fn kill(&mut self) -> io::Result<()> {
+        use sys::process::magenta::*;
+
+        unsafe { mx_cvt(mx_task_kill(self.handle.raw()))?; }
+
+        Ok(())
+    }
+
+    pub fn wait(&mut self) -> io::Result<ExitStatus> {
+        use default::Default;
+        use sys::process::magenta::*;
+
+        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.raw(), MX_TASK_TERMINATED,
+                                      MX_TIME_INFINITE, ptr::null_mut()))?;
+            mx_cvt(mx_object_get_info(self.handle.raw(), 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::InvalidData,
+                                      "Failed to get exit status of process"));
+        }
+        Ok(ExitStatus::new(proc_info.rec.return_code))
+    }
+}
+
+impl Drop for Process {
+    fn drop(&mut self) {
+        use sys::process::magenta::launchpad_destroy;
+        unsafe { launchpad_destroy(self.launchpad); }
+    }
+}
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))
+    }
+}