add crosvm_plugin dynamic library crate

This is the shared library used by the plugin process to speak to a
crosvm main process that spawned it.

TEST=cargo build --features plugin
BUG=chromium:800626

Change-Id: I100e7ddfc1099fbdf1462c171785a861e075d5d7
Reviewed-on: https://chromium-review.googlesource.com/869356
Commit-Ready: Zach Reizner <zachr@chromium.org>
Tested-by: Zach Reizner <zachr@chromium.org>
Reviewed-by: Zach Reizner <zachr@chromium.org>

2 files changed, 928 insertions, 0 deletions

diff --git a/crosvm_plugin/Cargo.toml b/crosvm_plugin/Cargo.toml
new file mode 100644
index 0000000..7b6491a
--- /dev/null
+++ b/crosvm_plugin/Cargo.toml
@@ -0,0 +1,15 @@
+[package]
+name = "crosvm_plugin"
+version = "0.5.0"
+authors = ["The Chromium OS Authors"]
+
+[lib]
+crate-type = ["cdylib"]
+
+[dependencies]
+protobuf = "*"
+plugin_proto = { path = "../plugin_proto" }
+sys_util = { path = "../sys_util" }
+kvm = { path = "../kvm" }
+kvm_sys = { path = "../kvm_sys" }
+libc = "*"
diff --git a/crosvm_plugin/src/lib.rs b/crosvm_plugin/src/lib.rs
new file mode 100644
index 0000000..1fb02a1
--- /dev/null
+++ b/crosvm_plugin/src/lib.rs
@@ -0,0 +1,913 @@
+// Copyright 2017 The Chromium OS Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#![allow(non_camel_case_types)]
+
+//! This module implements the dynamically loaded client library API used by a crosvm plugin,
+//! defined in `crosvm.h`. It implements the client half of the plugin protocol, which is defined in
+//! the plugin_proto module.
+//!
+//! To implement the `crosvm.h` C API, each function and struct definition is repeated here, with
+//! concrete definitions for each struct. Most functions are thin shims to the underlying object
+//! oriented Rust implementation method. Most methods require a request over the crosvm connection,
+//! which is done by creating a `MainRequest` or `VcpuRequest` protobuf and sending it over the
+//! connection's socket. Then, that socket is read for a `MainResponse` or `VcpuResponse`, which is
+//! translated to the appropriate return type for the C API.
+
+extern crate libc;
+extern crate sys_util;
+extern crate kvm;
+extern crate kvm_sys;
+extern crate plugin_proto;
+extern crate protobuf;
+
+use std::env;
+use std::fs::File;
+use std::mem::{swap, size_of};
+use std::os::raw::{c_int, c_void};
+use std::os::unix::io::{AsRawFd, IntoRawFd, FromRawFd, RawFd};
+use std::os::unix::net::UnixDatagram;
+use std::ptr::null_mut;
+use std::result;
+use std::slice::{from_raw_parts, from_raw_parts_mut};
+use std::slice;
+use std::sync::Arc;
+use std::sync::atomic::{AtomicUsize, Ordering};
+
+use libc::{ENOTCONN, EINVAL, EPROTO, ENOENT};
+
+use protobuf::{Message, ProtobufEnum, RepeatedField, parse_from_bytes};
+
+use sys_util::Scm;
+
+use kvm::dirty_log_bitmap_size;
+
+use kvm_sys::{kvm_regs, kvm_sregs, kvm_fpu};
+
+use plugin_proto::*;
+
+// Needs to be large enough to receive all the VCPU sockets.
+const MAX_DATAGRAM_FD: usize = 32;
+// Needs to be large enough for a sizable dirty log.
+const MAX_DATAGRAM_SIZE: usize = 0x40000;
+
+const CROSVM_IRQ_ROUTE_IRQCHIP: u32 = 0;
+const CROSVM_IRQ_ROUTE_MSI: u32 = 1;
+
+const CROSVM_VCPU_EVENT_KIND_INIT: u32 = 0;
+const CROSVM_VCPU_EVENT_KIND_IO_ACCESS: u32 = 1;
+const CROSVM_VCPU_EVENT_KIND_PAUSED: u32 = 2;
+
+#[repr(C)]
+#[derive(Copy, Clone)]
+pub struct anon_irqchip {
+    irqchip: u32,
+    pin: u32,
+}
+
+#[repr(C)]
+#[derive(Copy, Clone)]
+pub struct anon_msi {
+    address: u64,
+    data: u32,
+}
+
+#[repr(C)]
+pub union anon_route {
+    irqchip: anon_irqchip,
+    msi: anon_msi,
+    reserved: [u8; 16],
+}
+
+#[repr(C)]
+pub struct crosvm_irq_route {
+    irq_id: u32,
+    kind: u32,
+    route: anon_route,
+}
+
+fn proto_error_to_int(e: protobuf::ProtobufError) -> c_int {
+    match e {
+        protobuf::ProtobufError::IoError(e) => e.raw_os_error().unwrap_or(-EINVAL),
+        _ => -EINVAL,
+    }
+}
+
+fn fd_cast<F: FromRawFd>(f: File) -> F {
+    // Safe because we are transferring unique ownership.
+    unsafe { F::from_raw_fd(f.into_raw_fd()) }
+}
+
+#[derive(Default)]
+struct IdAllocator(AtomicUsize);
+
+impl IdAllocator {
+    fn alloc(&self) -> u32 {
+        self.0.fetch_add(1, Ordering::Relaxed) as u32
+    }
+
+    fn free(&self, id: u32) {
+        self.0
+            .compare_and_swap(id as usize + 1, id as usize, Ordering::Relaxed);
+    }
+}
+
+pub struct crosvm {
+    id_allocator: Arc<IdAllocator>,
+    socket: UnixDatagram,
+    fd_messager: Scm,
+    request_buffer: Vec<u8>,
+    response_buffer: Vec<u8>,
+    vcpus: Arc<Vec<crosvm_vcpu>>,
+}
+
+impl crosvm {
+    fn from_connection(socket: UnixDatagram) -> result::Result<crosvm, c_int> {
+        let mut crosvm = crosvm {
+            id_allocator: Default::default(),
+            socket,
+            fd_messager: Scm::new(MAX_DATAGRAM_FD),
+            request_buffer: Vec::new(),
+            response_buffer: vec![0; MAX_DATAGRAM_SIZE],
+            vcpus: Default::default(),
+        };
+        crosvm.load_all_vcpus()?;
+        Ok(crosvm)
+    }
+
+    fn new(id_allocator: Arc<IdAllocator>,
+           socket: UnixDatagram,
+           vcpus: Arc<Vec<crosvm_vcpu>>)
+           -> crosvm {
+        crosvm {
+            id_allocator,
+            socket,
+            fd_messager: Scm::new(MAX_DATAGRAM_FD),
+            request_buffer: Vec::new(),
+            response_buffer: vec![0; MAX_DATAGRAM_SIZE],
+            vcpus,
+        }
+    }
+
+    fn get_id_allocator(&self) -> &IdAllocator {
+        &*self.id_allocator
+    }
+
+    fn main_transaction(&mut self,
+                        request: &MainRequest,
+                        fds: &[RawFd])
+                        -> result::Result<(MainResponse, Vec<File>), c_int> {
+        self.request_buffer.clear();
+        request
+            .write_to_vec(&mut self.request_buffer)
+            .map_err(proto_error_to_int)?;
+        self.fd_messager
+            .send(&self.socket, &[self.request_buffer.as_slice()], fds)
+            .map_err(|e| e.errno())?;
+
+        let mut datagram_files = Vec::new();
+        let msg_size = self.fd_messager
+            .recv(&self.socket,
+                  &mut [&mut self.response_buffer],
+                  &mut datagram_files)
+            .map_err(|e| e.errno())?;
+
+        let response: MainResponse = parse_from_bytes(&self.response_buffer[..msg_size])
+            .map_err(proto_error_to_int)?;
+        if response.errno != 0 {
+            return Err(response.errno);
+        }
+        Ok((response, datagram_files))
+    }
+
+    fn try_clone(&mut self) -> result::Result<crosvm, c_int> {
+        let mut r = MainRequest::new();
+        r.mut_new_connection();
+        let mut files = self.main_transaction(&r, &[])?.1;
+        match files.pop() {
+            Some(new_socket) => {
+                Ok(crosvm::new(self.id_allocator.clone(),
+                               fd_cast(new_socket),
+                               self.vcpus.clone()))
+            }
+            None => Err(-EPROTO),
+        }
+    }
+
+    fn destroy(&mut self, id: u32) -> result::Result<(), c_int> {
+        let mut r = MainRequest::new();
+        r.mut_destroy().id = id;
+        self.main_transaction(&r, &[])?;
+        self.get_id_allocator().free(id);
+        Ok(())
+    }
+
+    // Only call this at `from_connection` function.
+    fn load_all_vcpus(&mut self) -> result::Result<(), c_int> {
+        let mut r = MainRequest::new();
+        r.mut_get_vcpus();
+        let (_, files) = self.main_transaction(&r, &[])?;
+        if files.is_empty() {
+            return Err(-EPROTO);
+        }
+        let vcpus = files
+            .into_iter()
+            .map(|f| crosvm_vcpu::new(fd_cast(f)))
+            .collect();
+        // Only called once by the `from_connection` constructor, which makes a new unique
+        // `self.vcpus`.
+        let self_vcpus = Arc::get_mut(&mut self.vcpus).unwrap();
+        *self_vcpus = vcpus;
+        Ok(())
+    }
+
+    fn get_shutdown_eventfd(&mut self) -> result::Result<File, c_int> {
+        let mut r = MainRequest::new();
+        r.mut_get_shutdown_eventfd();
+        let (_, mut files) = self.main_transaction(&r, &[])?;
+        match files.pop() {
+            Some(f) => Ok(f),
+            None => Err(-EPROTO),
+        }
+    }
+
+    fn reserve_range(&mut self, space: u32, start: u64, length: u64) -> result::Result<(), c_int> {
+        let mut r = MainRequest::new();
+        {
+            let reserve: &mut MainRequest_ReserveRange = r.mut_reserve_range();
+            reserve.space = AddressSpace::from_i32(space as i32).ok_or(-EINVAL)?;
+            reserve.start = start;
+            reserve.length = length;
+        }
+        self.main_transaction(&r, &[])?;
+        Ok(())
+    }
+
+    fn set_irq(&mut self, irq_id: u32, active: bool) -> result::Result<(), c_int> {
+        let mut r = MainRequest::new();
+        {
+            let set_irq: &mut MainRequest_SetIrq = r.mut_set_irq();
+            set_irq.irq_id = irq_id;
+            set_irq.active = active;
+        }
+        self.main_transaction(&r, &[])?;
+        Ok(())
+    }
+
+    fn set_irq_routing(&mut self, routing: &[crosvm_irq_route]) -> result::Result<(), c_int> {
+        let mut r = MainRequest::new();
+        {
+            let set_irq_routing: &mut RepeatedField<MainRequest_SetIrqRouting_Route> =
+                r.mut_set_irq_routing().mut_routes();
+            for route in routing {
+                let mut entry = MainRequest_SetIrqRouting_Route::new();
+                entry.irq_id = route.irq_id;
+                match route.kind {
+                    CROSVM_IRQ_ROUTE_IRQCHIP => {
+                        let irqchip: &mut MainRequest_SetIrqRouting_Route_Irqchip;
+                        irqchip = entry.mut_irqchip();
+                        // Safe because route.kind indicates which union field is valid.
+                        irqchip.irqchip = unsafe { route.route.irqchip }.irqchip;
+                        irqchip.pin = unsafe { route.route.irqchip }.pin;
+                    }
+                    CROSVM_IRQ_ROUTE_MSI => {
+                        let msi: &mut MainRequest_SetIrqRouting_Route_Msi = entry.mut_msi();
+                        // Safe because route.kind indicates which union field is valid.
+                        msi.address = unsafe { route.route.msi }.address;
+                        msi.data = unsafe { route.route.msi }.data;
+                    }
+                    _ => return Err(-EINVAL),
+                }
+                set_irq_routing.push(entry);
+            }
+        }
+        self.main_transaction(&r, &[])?;
+        Ok(())
+    }
+
+    fn set_identity_map_addr(&mut self, addr: u32) -> result::Result<(), c_int> {
+        let mut r = MainRequest::new();
+        r.mut_set_identity_map_addr().address = addr;
+        self.main_transaction(&r, &[])?;
+        Ok(())
+    }
+
+    fn pause_vcpus(&mut self, cpu_mask: u64, user: *mut c_void) -> result::Result<(), c_int> {
+        let mut r = MainRequest::new();
+        {
+            let pause_vcpus: &mut MainRequest_PauseVcpus = r.mut_pause_vcpus();
+            pause_vcpus.cpu_mask = cpu_mask;
+            pause_vcpus.user = user as u64;
+        }
+        self.main_transaction(&r, &[])?;
+        Ok(())
+    }
+
+    fn start(&mut self) -> result::Result<(), c_int> {
+        let mut r = MainRequest::new();
+        r.mut_start();
+        self.main_transaction(&r, &[])?;
+        Ok(())
+    }
+
+    fn get_vcpu(&mut self, cpu_id: u32) -> Option<*mut crosvm_vcpu> {
+        self.vcpus
+            .get(cpu_id as usize)
+            .map(|vcpu| vcpu as *const crosvm_vcpu as *mut crosvm_vcpu)
+    }
+}
+
+/// This helper macro implements the C API's constructor/destructor for a given type. Because they
+/// all follow the same pattern and include lots of boilerplate unsafe code, it makes sense to write
+/// it once with this helper macro.
+macro_rules! impl_ctor_dtor {
+    (
+        $t:ident,
+        $ctor:ident ( $( $x:ident: $y:ty ),* ),
+        $dtor:ident,
+    ) => {
+        #[allow(unused_unsafe)]
+        #[no_mangle]
+        pub unsafe extern fn $ctor(self_: *mut crosvm, $($x: $y,)* obj_ptr: *mut *mut $t) -> c_int {
+            let self_ = &mut (*self_);
+            match $t::create(self_, $($x,)*) {
+                Ok(obj) => {
+                    *obj_ptr = Box::into_raw(Box::new(obj));
+                    0
+                }
+                Err(e) => e,
+            }
+        }
+        #[no_mangle]
+        pub unsafe extern fn $dtor(self_: *mut crosvm, obj_ptr: *mut *mut $t) -> c_int {
+            let self_ = &mut (*self_);
+            let obj = Box::from_raw(*obj_ptr);
+            match self_.destroy(obj.id) {
+                Ok(_) => {
+                    *obj_ptr = null_mut();
+                    0
+                }
+                Err(e) =>  {
+                    Box::into_raw(obj);
+                    e
+                }
+            }
+        }
+    }
+}
+
+pub struct crosvm_io_event {
+    id: u32,
+    evt: File,
+}
+
+impl crosvm_io_event {
+    unsafe fn create(crosvm: &mut crosvm,
+                     space: u32,
+                     addr: u64,
+                     length: u32,
+                     datamatch: *const u8)
+                     -> result::Result<crosvm_io_event, c_int> {
+        let datamatch = match length {
+            0 => 0,
+            1 => *(datamatch as *const u8) as u64,
+            2 => *(datamatch as *const u16) as u64,
+            4 => *(datamatch as *const u32) as u64,
+            8 => *(datamatch as *const u64) as u64,
+            _ => return Err(-EINVAL),
+        };
+        Self::safe_create(crosvm, space, addr, length, datamatch)
+    }
+
+    fn safe_create(crosvm: &mut crosvm,
+                   space: u32,
+                   addr: u64,
+                   length: u32,
+                   datamatch: u64)
+                   -> result::Result<crosvm_io_event, c_int> {
+        let id = crosvm.get_id_allocator().alloc();
+        let mut r = MainRequest::new();
+        {
+            let create: &mut MainRequest_Create = r.mut_create();
+            create.id = id;
+            let io_event: &mut MainRequest_Create_IoEvent = create.mut_io_event();
+            io_event.space = AddressSpace::from_i32(space as i32).ok_or(-EINVAL)?;
+            io_event.address = addr;
+            io_event.length = length;
+            io_event.datamatch = datamatch;
+        }
+        let ret = match crosvm.main_transaction(&r, &[]) {
+            Ok((_, mut files)) => {
+                match files.pop() {
+                    Some(evt) => return Ok(crosvm_io_event { id, evt }),
+                    None => -EPROTO,
+                }
+            }
+            Err(e) => e,
+        };
+        crosvm.get_id_allocator().free(id);
+        Err(ret)
+    }
+}
+
+impl_ctor_dtor!(
+    crosvm_io_event,
+    crosvm_create_io_event(space: u32, addr: u64, len: u32, datamatch: *const u8),
+    crosvm_destroy_io_event,
+);
+
+#[no_mangle]
+pub unsafe extern "C" fn crosvm_io_event_fd(this: *mut crosvm_io_event) -> c_int {
+    (*this).evt.as_raw_fd()
+}
+
+pub struct crosvm_memory {
+    id: u32,
+    length: u64,
+}
+
+impl crosvm_memory {
+    fn create(crosvm: &mut crosvm,
+              fd: c_int,
+              offset: u64,
+              length: u64,
+              start: u64,
+              read_only: bool)
+              -> result::Result<crosvm_memory, c_int> {
+        const PAGE_MASK: u64 = 0x0fff;
+        if offset & PAGE_MASK != 0 || length & PAGE_MASK != 0 {
+            return Err(-EINVAL);
+        }
+        let id = crosvm.get_id_allocator().alloc();
+        let mut r = MainRequest::new();
+        {
+            let create: &mut MainRequest_Create = r.mut_create();
+            create.id = id;
+            let memory: &mut MainRequest_Create_Memory = create.mut_memory();
+            memory.offset = offset;
+            memory.start = start;
+            memory.length = length;
+            memory.read_only = read_only;
+        }
+        let ret = match crosvm.main_transaction(&r, &[fd]) {
+            Ok(_) => return Ok(crosvm_memory { id, length }),
+            Err(e) => e,
+        };
+        crosvm.get_id_allocator().free(id);
+        Err(ret)
+    }
+
+    fn get_dirty_log(&mut self, crosvm: &mut crosvm) -> result::Result<Vec<u8>, c_int> {
+        let mut r = MainRequest::new();
+        r.mut_dirty_log().id = self.id;
+        let (mut response, _) = crosvm.main_transaction(&r, &[])?;
+        if !response.has_dirty_log() {
+            return Err(-EPROTO);
+        }
+        Ok(response.take_dirty_log().bitmap)
+    }
+}
+
+impl_ctor_dtor!(
+    crosvm_memory,
+    crosvm_create_memory(fd: c_int, offset: u64, length: u64, start: u64, read_only: bool),
+    crosvm_destroy_memory,
+);
+
+#[no_mangle]
+pub unsafe extern "C" fn crosvm_memory_get_dirty_log(crosvm: *mut crosvm,
+                                                     this: *mut crosvm_memory,
+                                                     log: *mut u8)
+                                                     -> c_int {
+    let crosvm = &mut *crosvm;
+    let this = &mut *this;
+    let log_slice = slice::from_raw_parts_mut(log, dirty_log_bitmap_size(this.length as usize));
+    match this.get_dirty_log(crosvm) {
+        Ok(bitmap) => {
+            if bitmap.len() == log_slice.len() {
+                log_slice.copy_from_slice(&bitmap);
+                0
+            } else {
+                -EPROTO
+            }
+        }
+        Err(e) => e,
+    }
+}
+
+pub struct crosvm_irq_event {
+    id: u32,
+    trigger_evt: File,
+    resample_evt: File,
+}
+
+impl crosvm_irq_event {
+    fn create(crosvm: &mut crosvm, irq_id: u32) -> result::Result<crosvm_irq_event, c_int> {
+        let id = crosvm.get_id_allocator().alloc();
+        let mut r = MainRequest::new();
+        {
+            let create: &mut MainRequest_Create = r.mut_create();
+            create.id = id;
+            let irq_event: &mut MainRequest_Create_IrqEvent = create.mut_irq_event();
+            irq_event.irq_id = irq_id;
+            irq_event.resample = true;
+        }
+        let ret = match crosvm.main_transaction(&r, &[]) {
+            Ok((_, mut files)) => {
+                if files.len() >= 2 {
+                    let resample_evt = files.pop().unwrap();
+                    let trigger_evt = files.pop().unwrap();
+                    return Ok(crosvm_irq_event {
+                                  id,
+                                  trigger_evt,
+                                  resample_evt,
+                              });
+                }
+                -EPROTO
+            }
+            Err(e) => e,
+        };
+        crosvm.get_id_allocator().free(id);
+        Err(ret)
+    }
+}
+
+impl_ctor_dtor!(
+    crosvm_irq_event,
+    crosvm_create_irq_event(irq_id: u32),
+    crosvm_destroy_irq_event,
+);
+
+#[no_mangle]
+pub unsafe extern "C" fn crosvm_irq_event_get_fd(this: *mut crosvm_irq_event) -> c_int {
+    (*this).trigger_evt.as_raw_fd()
+}
+
+#[no_mangle]
+pub unsafe extern "C" fn crosvm_irq_event_get_resample_fd(this: *mut crosvm_irq_event) -> c_int {
+    (*this).resample_evt.as_raw_fd()
+}
+
+
+#[allow(dead_code)]
+#[derive(Copy, Clone)]
+#[repr(C)]
+struct anon_io_access {
+    address_space: u32,
+    __reserved0: [u8; 4],
+    address: u64,
+    data: *mut u8,
+    length: u32,
+    is_write: u8,
+    __reserved1: u8,
+}
+
+#[repr(C)]
+union anon_vcpu_event {
+    io_access: anon_io_access,
+    user: *mut c_void,
+    #[allow(dead_code)]
+    __reserved: [u8; 64],
+}
+
+#[repr(C)]
+pub struct crosvm_vcpu_event {
+    kind: u32,
+    __reserved: [u8; 4],
+    event: anon_vcpu_event,
+}
+
+pub struct crosvm_vcpu {
+    socket: UnixDatagram,
+    request_buffer: Vec<u8>,
+    response_buffer: Vec<u8>,
+    resume_data: Vec<u8>,
+}
+
+impl crosvm_vcpu {
+    fn new(socket: UnixDatagram) -> crosvm_vcpu {
+        crosvm_vcpu {
+            socket,
+            request_buffer: Vec::new(),
+            response_buffer: vec![0; MAX_DATAGRAM_SIZE],
+            resume_data: Vec::new(),
+        }
+    }
+
+    fn vcpu_transaction(&mut self, request: &VcpuRequest) -> result::Result<VcpuResponse, c_int> {
+        self.request_buffer.clear();
+        request
+            .write_to_vec(&mut self.request_buffer)
+            .map_err(proto_error_to_int)?;
+        self.socket
+            .send(self.request_buffer.as_slice())
+            .map_err(|e| e.raw_os_error().unwrap_or(-EINVAL))?;
+
+        let msg_size = self.socket
+            .recv(&mut self.response_buffer)
+            .map_err(|e| e.raw_os_error().unwrap_or(-EINVAL))?;
+
+        let response: VcpuResponse = parse_from_bytes(&self.response_buffer[..msg_size])
+            .map_err(proto_error_to_int)?;
+        if response.errno != 0 {
+            return Err(response.errno);
+        }
+        Ok(response)
+    }
+
+    fn wait(&mut self, event: &mut crosvm_vcpu_event) -> result::Result<(), c_int> {
+        let mut r = VcpuRequest::new();
+        r.mut_wait();
+        let mut response: VcpuResponse = self.vcpu_transaction(&r)?;
+        if !response.has_wait() {
+            return Err(-EPROTO);
+        }
+        let wait: &mut VcpuResponse_Wait = response.mut_wait();
+        if wait.has_init() {
+            event.kind = CROSVM_VCPU_EVENT_KIND_INIT;
+            Ok(())
+        } else if wait.has_io() {
+            let mut io: VcpuResponse_Wait_Io = wait.take_io();
+            event.kind = CROSVM_VCPU_EVENT_KIND_IO_ACCESS;
+            event.event.io_access = anon_io_access {
+                address_space: io.space.value() as u32,
+                __reserved0: Default::default(),
+                address: io.address,
+                data: io.data.as_mut_ptr(),
+                length: io.data.len() as u32,
+                is_write: io.is_write as u8,
+                __reserved1: Default::default(),
+            };
+            self.resume_data = io.data;
+            Ok(())
+        } else if wait.has_user() {
+            let user: &VcpuResponse_Wait_User = wait.get_user();
+            event.kind = CROSVM_VCPU_EVENT_KIND_PAUSED;
+            event.event.user = user.user as *mut c_void;
+            Ok(())
+        } else {
+            Err(-EPROTO)
+        }
+    }
+
+    fn resume(&mut self) -> result::Result<(), c_int> {
+        let mut r = VcpuRequest::new();
+        {
+            let resume: &mut VcpuRequest_Resume = r.mut_resume();
+            swap(&mut resume.data, &mut self.resume_data);
+        }
+        self.vcpu_transaction(&r)?;
+        Ok(())
+    }
+
+    fn get_state(&mut self,
+                 state_set: VcpuRequest_StateSet,
+                 out: &mut [u8])
+                 -> result::Result<(), c_int> {
+        let mut r = VcpuRequest::new();
+        r.mut_get_state().set = state_set;
+        let response = self.vcpu_transaction(&r)?;
+        if !response.has_get_state() {
+            return Err(-EPROTO);
+        }
+        let get_state: &VcpuResponse_GetState = response.get_get_state();
+        if get_state.state.len() != out.len() {
+            return Err(-EPROTO);
+        }
+        out.copy_from_slice(&get_state.state);
+        Ok(())
+    }
+
+    fn set_state(&mut self,
+                 state_set: VcpuRequest_StateSet,
+                 new_state: &[u8])
+                 -> result::Result<(), c_int> {
+        let mut r = VcpuRequest::new();
+        {
+            let set_state: &mut VcpuRequest_SetState = r.mut_set_state();
+            set_state.set = state_set;
+            set_state.state = new_state.to_vec();
+        }
+        self.vcpu_transaction(&r)?;
+        Ok(())
+    }
+}
+
+#[no_mangle]
+pub unsafe extern "C" fn crosvm_connect(out: *mut *mut crosvm) -> c_int {
+    let socket_name = match env::var("CROSVM_SOCKET") {
+        Ok(v) => v,
+        _ => return -ENOTCONN,
+    };
+
+    let socket = match socket_name.parse() {
+        Ok(v) if v < 0 => return -EINVAL,
+        Ok(v) => v,
+        _ => return -EINVAL,
+    };
+
+    let socket = UnixDatagram::from_raw_fd(socket);
+    let crosvm = match crosvm::from_connection(socket) {
+        Ok(c) => c,
+        Err(e) => return e,
+    };
+    *out = Box::into_raw(Box::new(crosvm));
+    0
+}
+
+#[no_mangle]
+pub unsafe extern "C" fn crosvm_new_connection(self_: *mut crosvm, out: *mut *mut crosvm) -> c_int {
+    let self_ = &mut (*self_);
+    match self_.try_clone() {
+        Ok(cloned) => {
+            *out = Box::into_raw(Box::new(cloned));
+            0
+        }
+        Err(e) => e,
+    }
+}
+
+#[no_mangle]
+pub unsafe extern "C" fn crosvm_destroy_connection(self_: *mut *mut crosvm) -> c_int {
+    Box::from_raw(*self_);
+    *self_ = null_mut();
+    0
+}
+
+#[no_mangle]
+pub unsafe extern "C" fn crosvm_get_shutdown_eventfd(self_: *mut crosvm) -> c_int {
+    let self_ = &mut (*self_);
+    match self_.get_shutdown_eventfd() {
+        Ok(f) => f.into_raw_fd(),
+        Err(e) => e,
+    }
+}
+
+#[no_mangle]
+pub unsafe extern "C" fn crosvm_reserve_range(self_: *mut crosvm,
+                                              space: u32,
+                                              start: u64,
+                                              length: u64)
+                                              -> c_int {
+    let self_ = &mut (*self_);
+    match self_.reserve_range(space, start, length) {
+        Ok(_) => 0,
+        Err(e) => e,
+    }
+}
+
+#[no_mangle]
+pub unsafe extern "C" fn crosvm_set_irq(self_: *mut crosvm, irq_id: u32, active: bool) -> c_int {
+    let self_ = &mut (*self_);
+    match self_.set_irq(irq_id, active) {
+        Ok(_) => 0,
+        Err(e) => e,
+    }
+}
+
+#[no_mangle]
+pub unsafe extern "C" fn crosvm_set_irq_routing(self_: *mut crosvm,
+                                                route_count: u32,
+                                                routes: *const crosvm_irq_route)
+                                                -> c_int {
+    let self_ = &mut (*self_);
+    match self_.set_irq_routing(slice::from_raw_parts(routes, route_count as usize)) {
+        Ok(_) => 0,
+        Err(e) => e,
+    }
+}
+
+#[no_mangle]
+pub unsafe extern "C" fn crosvm_set_identity_map_addr(self_: *mut crosvm, addr: u32) -> c_int {
+    let self_ = &mut (*self_);
+    match self_.set_identity_map_addr(addr) {
+        Ok(_) => 0,
+        Err(e) => e,
+    }
+}
+
+#[no_mangle]
+pub unsafe extern "C" fn crosvm_pause_vcpus(self_: *mut crosvm,
+                                            cpu_mask: u64,
+                                            user: *mut c_void)
+                                            -> c_int {
+    let self_ = &mut (*self_);
+    match self_.pause_vcpus(cpu_mask, user) {
+        Ok(_) => 0,
+        Err(e) => e,
+    }
+}
+
+#[no_mangle]
+pub unsafe extern "C" fn crosvm_start(self_: *mut crosvm) -> c_int {
+    let self_ = &mut (*self_);
+    match self_.start() {
+        Ok(_) => 0,
+        Err(e) => e,
+    }
+}
+
+#[no_mangle]
+pub unsafe extern "C" fn crosvm_get_vcpu(self_: *mut crosvm,
+                                         cpu_id: u32,
+                                         out: *mut *mut crosvm_vcpu)
+                                         -> c_int {
+    let self_ = &mut (*self_);
+    match self_.get_vcpu(cpu_id) {
+        Some(vcpu) => {
+            *out = vcpu;
+            0
+        }
+        None => -ENOENT,
+    }
+}
+
+#[no_mangle]
+pub unsafe extern "C" fn crosvm_vcpu_wait(this: *mut crosvm_vcpu,
+                                          event: *mut crosvm_vcpu_event)
+                                          -> c_int {
+    let this = &mut *this;
+    let event = &mut *event;
+    match this.wait(event) {
+        Ok(_) => 0,
+        Err(e) => e,
+    }
+}
+
+#[no_mangle]
+pub unsafe extern "C" fn crosvm_vcpu_resume(this: *mut crosvm_vcpu) -> c_int {
+    let this = &mut *this;
+    match this.resume() {
+        Ok(_) => 0,
+        Err(e) => e,
+    }
+}
+
+#[no_mangle]
+pub unsafe extern "C" fn crosvm_vcpu_get_regs(this: *mut crosvm_vcpu,
+                                              regs: *mut kvm_regs)
+                                              -> c_int {
+    let this = &mut *this;
+    let regs = from_raw_parts_mut(regs as *mut u8, size_of::<kvm_regs>());
+    match this.get_state(VcpuRequest_StateSet::REGS, regs) {
+        Ok(_) => 0,
+        Err(e) => e,
+    }
+}
+
+#[no_mangle]
+pub unsafe extern "C" fn crosvm_vcpu_set_regs(this: *mut crosvm_vcpu,
+                                              regs: *const kvm_regs)
+                                              -> c_int {
+    let this = &mut *this;
+    let regs = from_raw_parts(regs as *mut u8, size_of::<kvm_regs>());
+    match this.set_state(VcpuRequest_StateSet::REGS, regs) {
+        Ok(_) => 0,
+        Err(e) => e,
+    }
+}
+
+#[no_mangle]
+pub unsafe extern "C" fn crosvm_vcpu_get_sregs(this: *mut crosvm_vcpu,
+                                               sregs: *mut kvm_sregs)
+                                               -> c_int {
+    let this = &mut *this;
+    let sregs = from_raw_parts_mut(sregs as *mut u8, size_of::<kvm_sregs>());
+    match this.get_state(VcpuRequest_StateSet::SREGS, sregs) {
+        Ok(_) => 0,
+        Err(e) => e,
+    }
+}
+
+#[no_mangle]
+pub unsafe extern "C" fn crosvm_vcpu_set_sregs(this: *mut crosvm_vcpu,
+                                               sregs: *const kvm_sregs)
+                                               -> c_int {
+    let this = &mut *this;
+    let sregs = from_raw_parts(sregs as *mut u8, size_of::<kvm_sregs>());
+    match this.set_state(VcpuRequest_StateSet::SREGS, sregs) {
+        Ok(_) => 0,
+        Err(e) => e,
+    }
+}
+
+#[no_mangle]
+pub unsafe extern "C" fn crosvm_vcpu_get_fpu(this: *mut crosvm_vcpu, fpu: *mut kvm_fpu) -> c_int {
+    let this = &mut *this;
+    let fpu = from_raw_parts_mut(fpu as *mut u8, size_of::<kvm_fpu>());
+    match this.get_state(VcpuRequest_StateSet::FPU, fpu) {
+        Ok(_) => 0,
+        Err(e) => e,
+    }
+}
+
+#[no_mangle]
+pub unsafe extern "C" fn crosvm_vcpu_set_fpu(this: *mut crosvm_vcpu, fpu: *const kvm_fpu) -> c_int {
+    let this = &mut *this;
+    let fpu = from_raw_parts(fpu as *mut u8, size_of::<kvm_fpu>());
+    match this.set_state(VcpuRequest_StateSet::FPU, fpu) {
+        Ok(_) => 0,
+        Err(e) => e,
+    }
+}