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

Author: bors

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
     }
 }
 

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 {

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();

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;
+}

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;