src/main.rs

// 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.

//! Runs a virtual machine under KVM

#[cfg(any(target_arch = "arm", target_arch = "aarch64"))]
extern crate aarch64;
extern crate arch;
extern crate audio_streams;
extern crate byteorder;
extern crate devices;
extern crate io_jail;
extern crate kernel_cmdline;
extern crate kernel_loader;
extern crate kvm;
extern crate kvm_sys;
extern crate libc;
extern crate libcras;
extern crate net_util;
extern crate qcow;
#[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
extern crate x86_64;
#[macro_use]
extern crate sys_util;
extern crate data_model;
#[cfg(feature = "wl-dmabuf")]
extern crate gpu_buffer;
extern crate msg_socket;
#[cfg(feature = "plugin")]
extern crate plugin_proto;
#[cfg(feature = "plugin")]
extern crate protobuf;
extern crate rand_ish;
extern crate resources;
extern crate sync;
extern crate vhost;
extern crate vm_control;

pub mod argument;
pub mod linux;
pub mod panic_hook;
#[cfg(feature = "plugin")]
pub mod plugin;

use std::fs::OpenOptions;
use std::net;
use std::os::unix::io::RawFd;
use std::path::PathBuf;
use std::string::String;
use std::thread::sleep;
use std::time::Duration;

use qcow::QcowFile;
use sys_util::{getpid, kill_process_group, net::UnixSeqpacket, reap_child, syslog};

use argument::{print_help, set_arguments, Argument};
use msg_socket::{MsgReceiver, MsgSender, MsgSocket};
use vm_control::{VmRequest, VmResponse};

static SECCOMP_POLICY_DIR: &'static str = "/usr/share/policy/crosvm";

struct DiskOption {
    path: PathBuf,
    read_only: bool,
}

#[allow(dead_code)]
struct BindMount {
    src: PathBuf,
    dst: PathBuf,
    writable: bool,
}

#[allow(dead_code)]
struct GidMap {
    inner: libc::gid_t,
    outer: libc::gid_t,
    count: u32,
}

const DEFAULT_TRACKPAD_WIDTH: u32 = 800;
const DEFAULT_TRACKPAD_HEIGHT: u32 = 1280;

struct TrackpadOption {
    path: PathBuf,
    width: u32,
    height: u32,
}

impl TrackpadOption {
    fn new(path: PathBuf) -> TrackpadOption {
        TrackpadOption {
            path,
            width: DEFAULT_TRACKPAD_WIDTH,
            height: DEFAULT_TRACKPAD_HEIGHT,
        }
    }
}

pub struct Config {
    vcpu_count: Option<u32>,
    memory: Option<usize>,
    kernel_path: PathBuf,
    android_fstab: Option<PathBuf>,
    initrd_path: Option<PathBuf>,
    params: Vec<String>,
    socket_path: Option<PathBuf>,
    plugin: Option<PathBuf>,
    plugin_root: Option<PathBuf>,
    plugin_mounts: Vec<BindMount>,
    plugin_gid_maps: Vec<GidMap>,
    disks: Vec<DiskOption>,
    host_ip: Option<net::Ipv4Addr>,
    netmask: Option<net::Ipv4Addr>,
    mac_address: Option<net_util::MacAddress>,
    vhost_net: bool,
    tap_fd: Vec<RawFd>,
    cid: Option<u64>,
    wayland_socket_path: Option<PathBuf>,
    wayland_dmabuf: bool,
    shared_dirs: Vec<(PathBuf, String)>,
    multiprocess: bool,
    seccomp_policy_dir: PathBuf,
    gpu: bool,
    software_tpm: bool,
    cras_audio: bool,
    null_audio: bool,
    virtio_trackpad: Option<TrackpadOption>,
    virtio_mouse: Option<PathBuf>,
    virtio_keyboard: Option<PathBuf>,
    virtio_input_evdevs: Vec<PathBuf>,
    split_irqchip: bool,
}

impl Default for Config {
    fn default() -> Config {
        Config {
            vcpu_count: None,
            memory: None,
            kernel_path: PathBuf::default(),
            android_fstab: None,
            initrd_path: None,
            params: Vec::new(),
            socket_path: None,
            plugin: None,
            plugin_root: None,
            plugin_mounts: Vec::new(),
            plugin_gid_maps: Vec::new(),
            disks: Vec::new(),
            host_ip: None,
            netmask: None,
            mac_address: None,
            vhost_net: false,
            tap_fd: Vec::new(),
            cid: None,
            gpu: false,
            software_tpm: false,
            wayland_socket_path: None,
            wayland_dmabuf: false,
            shared_dirs: Vec::new(),
            multiprocess: !cfg!(feature = "default-no-sandbox"),
            seccomp_policy_dir: PathBuf::from(SECCOMP_POLICY_DIR),
            cras_audio: false,
            null_audio: false,
            virtio_trackpad: None,
            virtio_mouse: None,
            virtio_keyboard: None,
            virtio_input_evdevs: Vec::new(),
            split_irqchip: false,
        }
    }
}

// Wait for all children to exit. Return true if they have all exited, false
// otherwise.
fn wait_all_children() -> bool {
    const CHILD_WAIT_MAX_ITER: isize = 100;
    const CHILD_WAIT_MS: u64 = 10;
    for _ in 0..CHILD_WAIT_MAX_ITER {
        loop {
            match reap_child() {
                Ok(0) => break,
                // We expect ECHILD which indicates that there were no children left.
                Err(e) if e.errno() == libc::ECHILD => return true,
                Err(e) => {
                    warn!("error while waiting for children: {}", e);
                    return false;
                }
                // We reaped one child, so continue reaping.
                _ => {}
            }
        }
        // There's no timeout option for waitpid which reap_child calls internally, so our only
        // recourse is to sleep while waiting for the children to exit.
        sleep(Duration::from_millis(CHILD_WAIT_MS));
    }

    // If we've made it to this point, not all of the children have exited.
    false
}

fn set_argument(cfg: &mut Config, name: &str, value: Option<&str>) -> argument::Result<()> {
    match name {
        "" => {
            if cfg.plugin.is_some() {
                return Err(argument::Error::TooManyArguments(
                    "`plugin` can not be used with kernel".to_owned(),
                ));
            } else if !cfg.kernel_path.as_os_str().is_empty() {
                return Err(argument::Error::TooManyArguments(
                    "expected exactly one kernel path".to_owned(),
                ));
            } else {
                let kernel_path = PathBuf::from(value.unwrap());
                if !kernel_path.exists() {
                    return Err(argument::Error::InvalidValue {
                        value: value.unwrap().to_owned(),
                        expected: "this kernel path does not exist",
                    });
                }
                cfg.kernel_path = kernel_path;
            }
        }
        "android-fstab" => {
            if cfg.android_fstab.is_some()
                && !cfg.android_fstab.as_ref().unwrap().as_os_str().is_empty()
            {
                return Err(argument::Error::TooManyArguments(
                    "expected exactly one android fstab path".to_owned(),
                ));
            } else {
                let android_fstab = PathBuf::from(value.unwrap());
                if !android_fstab.exists() {
                    return Err(argument::Error::InvalidValue {
                        value: value.unwrap().to_owned(),
                        expected: "this android fstab path does not exist",
                    });
                }
                cfg.android_fstab = Some(android_fstab);
            }
        }
        "params" => {
            cfg.params.push(value.unwrap().to_owned());
        }
        "cpus" => {
            if cfg.vcpu_count.is_some() {
                return Err(argument::Error::TooManyArguments(
                    "`cpus` already given".to_owned(),
                ));
            }
            cfg.vcpu_count =
                Some(
                    value
                        .unwrap()
                        .parse()
                        .map_err(|_| argument::Error::InvalidValue {
                            value: value.unwrap().to_owned(),
                            expected: "this value for `cpus` needs to be integer",
                        })?,
                )
        }
        "mem" => {
            if cfg.memory.is_some() {
                return Err(argument::Error::TooManyArguments(
                    "`mem` already given".to_owned(),
                ));
            }
            cfg.memory =
                Some(
                    value
                        .unwrap()
                        .parse()
                        .map_err(|_| argument::Error::InvalidValue {
                            value: value.unwrap().to_owned(),
                            expected: "this value for `mem` needs to be integer",
                        })?,
                )
        }
        "cras-audio" => {
            cfg.cras_audio = true;
        }
        "null-audio" => {
            cfg.null_audio = true;
        }
        "root" | "disk" | "rwdisk" | "qcow" | "rwqcow" => {
            let disk_path = PathBuf::from(value.unwrap());
            if !disk_path.exists() {
                return Err(argument::Error::InvalidValue {
                    value: value.unwrap().to_owned(),
                    expected: "this disk path does not exist",
                });
            }
            if name == "root" {
                if cfg.disks.len() >= 26 {
                    return Err(argument::Error::TooManyArguments(
                        "ran out of letters for to assign to root disk".to_owned(),
                    ));
                }
                cfg.params.push(format!(
                    "root=/dev/vd{} ro",
                    char::from(b'a' + cfg.disks.len() as u8)
                ));
            }
            cfg.disks.push(DiskOption {
                path: disk_path,
                read_only: !name.starts_with("rw"),
            });
        }
        "host_ip" => {
            if cfg.host_ip.is_some() {
                return Err(argument::Error::TooManyArguments(
                    "`host_ip` already given".to_owned(),
                ));
            }
            cfg.host_ip =
                Some(
                    value
                        .unwrap()
                        .parse()
                        .map_err(|_| argument::Error::InvalidValue {
                            value: value.unwrap().to_owned(),
                            expected: "`host_ip` needs to be in the form \"x.x.x.x\"",
                        })?,
                )
        }
        "netmask" => {
            if cfg.netmask.is_some() {
                return Err(argument::Error::TooManyArguments(
                    "`netmask` already given".to_owned(),
                ));
            }
            cfg.netmask =
                Some(
                    value
                        .unwrap()
                        .parse()
                        .map_err(|_| argument::Error::InvalidValue {
                            value: value.unwrap().to_owned(),
                            expected: "`netmask` needs to be in the form \"x.x.x.x\"",
                        })?,
                )
        }
        "mac" => {
            if cfg.mac_address.is_some() {
                return Err(argument::Error::TooManyArguments(
                    "`mac` already given".to_owned(),
                ));
            }
            cfg.mac_address =
                Some(
                    value
                        .unwrap()
                        .parse()
                        .map_err(|_| argument::Error::InvalidValue {
                            value: value.unwrap().to_owned(),
                            expected: "`mac` needs to be in the form \"XX:XX:XX:XX:XX:XX\"",
                        })?,
                )
        }
        "wayland-sock" => {
            if cfg.wayland_socket_path.is_some() {
                return Err(argument::Error::TooManyArguments(
                    "`wayland-sock` already given".to_owned(),
                ));
            }
            let wayland_socket_path = PathBuf::from(value.unwrap());
            if !wayland_socket_path.exists() {
                return Err(argument::Error::InvalidValue {
                    value: value.unwrap().to_string(),
                    expected: "Wayland socket does not exist",
                });
            }
            cfg.wayland_socket_path = Some(wayland_socket_path);
        }
        #[cfg(feature = "wl-dmabuf")]
        "wayland-dmabuf" => cfg.wayland_dmabuf = true,
        "socket" => {
            if cfg.socket_path.is_some() {
                return Err(argument::Error::TooManyArguments(
                    "`socket` already given".to_owned(),
                ));
            }
            let mut socket_path = PathBuf::from(value.unwrap());
            if socket_path.is_dir() {
                socket_path.push(format!("crosvm-{}.sock", getpid()));
            }
            if socket_path.exists() {
                return Err(argument::Error::InvalidValue {
                    value: socket_path.to_string_lossy().into_owned(),
                    expected: "this socket path already exists",
                });
            }
            cfg.socket_path = Some(socket_path);
        }
        "multiprocess" => {
            cfg.multiprocess = true;
        }
        "disable-sandbox" => {
            cfg.multiprocess = false;
        }
        "cid" => {
            if cfg.cid.is_some() {
                return Err(argument::Error::TooManyArguments(
                    "`cid` alread given".to_owned(),
                ));
            }
            cfg.cid = Some(
                value
                    .unwrap()
                    .parse()
                    .map_err(|_| argument::Error::InvalidValue {
                        value: value.unwrap().to_owned(),
                        expected: "this value for `cid` must be an unsigned integer",
                    })?,
            );
        }
        "shared-dir" => {
            // Formatted as <src:tag>.
            let param = value.unwrap();
            let mut components = param.splitn(2, ':');
            let src =
                PathBuf::from(
                    components
                        .next()
                        .ok_or_else(|| argument::Error::InvalidValue {
                            value: param.to_owned(),
                            expected: "missing source path for `shared-dir`",
                        })?,
                );
            let tag = components
                .next()
                .ok_or_else(|| argument::Error::InvalidValue {
                    value: param.to_owned(),
                    expected: "missing tag for `shared-dir`",
                })?
                .to_owned();

            if !src.is_dir() {
                return Err(argument::Error::InvalidValue {
                    value: param.to_owned(),
                    expected: "source path for `shared-dir` must be a directory",
                });
            }

            cfg.shared_dirs.push((src, tag));
        }
        "seccomp-policy-dir" => {
            // `value` is Some because we are in this match so it's safe to unwrap.
            cfg.seccomp_policy_dir = PathBuf::from(value.unwrap());
        }
        "plugin" => {
            if !cfg.kernel_path.as_os_str().is_empty() {
                return Err(argument::Error::TooManyArguments(
                    "`plugin` can not be used with kernel".to_owned(),
                ));
            } else if cfg.plugin.is_some() {
                return Err(argument::Error::TooManyArguments(
                    "`plugin` already given".to_owned(),
                ));
            }
            let plugin = PathBuf::from(value.unwrap().to_owned());
            if plugin.is_relative() {
                return Err(argument::Error::InvalidValue {
                    value: plugin.to_string_lossy().into_owned(),
                    expected: "the plugin path must be an absolute path",
                });
            }
            cfg.plugin = Some(plugin);
        }
        "plugin-root" => {
            cfg.plugin_root = Some(PathBuf::from(value.unwrap().to_owned()));
        }
        "plugin-mount" => {
            let components: Vec<&str> = value.unwrap().split(":").collect();
            if components.len() != 3 {
                return Err(argument::Error::InvalidValue {
                    value: value.unwrap().to_owned(),
                    expected:
                        "`plugin-mount` must have exactly 3 components: <src>:<dst>:<writable>",
                });
            }

            let src = PathBuf::from(components[0]);
            if src.is_relative() {
                return Err(argument::Error::InvalidValue {
                    value: components[0].to_owned(),
                    expected: "the source path for `plugin-mount` must be absolute",
                });
            }
            if !src.exists() {
                return Err(argument::Error::InvalidValue {
                    value: components[0].to_owned(),
                    expected: "the source path for `plugin-mount` does not exist",
                });
            }

            let dst = PathBuf::from(components[1]);
            if dst.is_relative() {
                return Err(argument::Error::InvalidValue {
                    value: components[1].to_owned(),
                    expected: "the destination path for `plugin-mount` must be absolute",
                });
            }

            let writable: bool =
                components[2]
                    .parse()
                    .map_err(|_| argument::Error::InvalidValue {
                        value: components[2].to_owned(),
                        expected: "the <writable> component for `plugin-mount` is not valid bool",
                    })?;

            cfg.plugin_mounts.push(BindMount { src, dst, writable });
        }
        "plugin-gid-map" => {
            let components: Vec<&str> = value.unwrap().split(":").collect();
            if components.len() != 3 {
                return Err(argument::Error::InvalidValue {
                    value: value.unwrap().to_owned(),
                    expected:
                        "`plugin-gid-map` must have exactly 3 components: <inner>:<outer>:<count>",
                });
            }

            let inner: libc::gid_t =
                components[0]
                    .parse()
                    .map_err(|_| argument::Error::InvalidValue {
                        value: components[0].to_owned(),
                        expected: "the <inner> component for `plugin-gid-map` is not valid gid",
                    })?;

            let outer: libc::gid_t =
                components[1]
                    .parse()
                    .map_err(|_| argument::Error::InvalidValue {
                        value: components[1].to_owned(),
                        expected: "the <outer> component for `plugin-gid-map` is not valid gid",
                    })?;

            let count: u32 = components[2]
                .parse()
                .map_err(|_| argument::Error::InvalidValue {
                    value: components[2].to_owned(),
                    expected: "the <count> component for `plugin-gid-map` is not valid number",
                })?;

            cfg.plugin_gid_maps.push(GidMap {
                inner,
                outer,
                count,
            });
        }
        "vhost-net" => cfg.vhost_net = true,
        "tap-fd" => {
            cfg.tap_fd.push(
                value
                    .unwrap()
                    .parse()
                    .map_err(|_| argument::Error::InvalidValue {
                        value: value.unwrap().to_owned(),
                        expected: "this value for `tap-fd` must be an unsigned integer",
                    })?,
            );
        }
        "gpu" => {
            cfg.gpu = true;
        }
        "software-tpm" => {
            cfg.software_tpm = true;
        }
        "trackpad" => {
            if cfg.virtio_trackpad.is_some() {
                return Err(argument::Error::TooManyArguments(
                    "`trackpad` already given".to_owned(),
                ));
            }
            let mut it = value.unwrap().split(":");

            let mut trackpad_spec =
                TrackpadOption::new(PathBuf::from(it.next().unwrap().to_owned()));
            if let Some(width) = it.next() {
                trackpad_spec.width = width.trim().parse().unwrap();
            }
            if let Some(height) = it.next() {
                trackpad_spec.height = height.trim().parse().unwrap();
            }

            cfg.virtio_trackpad = Some(trackpad_spec);
        }
        "mouse" => {
            if cfg.virtio_mouse.is_some() {
                return Err(argument::Error::TooManyArguments(
                    "`mouse` already given".to_owned(),
                ));
            }
            cfg.virtio_mouse = Some(PathBuf::from(value.unwrap().to_owned()));
        }
        "keyboard" => {
            if cfg.virtio_keyboard.is_some() {
                return Err(argument::Error::TooManyArguments(
                    "`keyboard` already given".to_owned(),
                ));
            }
            cfg.virtio_keyboard = Some(PathBuf::from(value.unwrap().to_owned()));
        }
        "evdev" => {
            let dev_path = PathBuf::from(value.unwrap());
            if !dev_path.exists() {
                return Err(argument::Error::InvalidValue {
                    value: value.unwrap().to_owned(),
                    expected: "this input device path does not exist",
                });
            }
            cfg.virtio_input_evdevs.push(dev_path);
        }
        "split-irqchip" => {
            cfg.split_irqchip = true;
        }
        "initrd" => {
            cfg.initrd_path = Some(PathBuf::from(value.unwrap().to_owned()));
        }
        "help" => return Err(argument::Error::PrintHelp),
        _ => unreachable!(),
    }
    Ok(())
}

fn run_vm(args: std::env::Args) -> std::result::Result<(), ()> {
    let arguments =
        &[Argument::positional("KERNEL", "bzImage of kernel to run"),
          Argument::value("android-fstab", "PATH", "Path to Android fstab"),
          Argument::short_value('i', "initrd", "PATH", "Initial ramdisk to load."),
          Argument::short_value('p',
                                "params",
                                "PARAMS",
                                "Extra kernel or plugin command line arguments. Can be given more than once."),
          Argument::short_value('c', "cpus", "N", "Number of VCPUs. (default: 1)"),
          Argument::short_value('m',
                                "mem",
                                "N",
                                "Amount of guest memory in MiB. (default: 256)"),
          Argument::short_value('r',
                                "root",
                                "PATH",
                                "Path to a root disk image. Like `--disk` but adds appropriate kernel command line option."),
          Argument::short_value('d', "disk", "PATH", "Path to a disk image."),
          Argument::value("qcow", "PATH", "Path to a qcow2 disk image. (Deprecated; use --disk instead.)"),
          Argument::value("rwdisk", "PATH", "Path to a writable disk image."),
          Argument::value("rwqcow", "PATH", "Path to a writable qcow2 disk image. (Deprecated; use --rwdisk instead.)"),
          Argument::value("host_ip",
                          "IP",
                          "IP address to assign to host tap interface."),
          Argument::value("netmask", "NETMASK", "Netmask for VM subnet."),
          Argument::value("mac", "MAC", "MAC address for VM."),
          Argument::flag("cras-audio", "Add an audio device to the VM that plays samples through CRAS server"),
          Argument::flag("null-audio", "Add an audio device to the VM that plays samples to /dev/null"),
          Argument::value("wayland-sock", "PATH", "Path to the Wayland socket to use."),
          #[cfg(feature = "wl-dmabuf")]
          Argument::flag("wayland-dmabuf", "Enable support for DMABufs in Wayland device."),
          Argument::short_value('s',
                                "socket",
                                "PATH",
                                "Path to put the control socket. If PATH is a directory, a name will be generated."),
          Argument::short_flag('u', "multiprocess", "Run each device in a child process(default)."),
          Argument::flag("disable-sandbox", "Run all devices in one, non-sandboxed process."),
          Argument::value("cid", "CID", "Context ID for virtual sockets."),
          Argument::value("shared-dir", "PATH:TAG",
                          "Directory to be shared with a VM as a source:tag pair. Can be given more than once."),
          Argument::value("seccomp-policy-dir", "PATH", "Path to seccomp .policy files."),
          #[cfg(feature = "plugin")]
          Argument::value("plugin", "PATH", "Absolute path to plugin process to run under crosvm."),
          #[cfg(feature = "plugin")]
          Argument::value("plugin-root", "PATH", "Absolute path to a directory that will become root filesystem for the plugin process."),
          #[cfg(feature = "plugin")]
          Argument::value("plugin-mount", "PATH:PATH:BOOL", "Path to be mounted into the plugin's root filesystem.  Can be given more than once."),
          #[cfg(feature = "plugin")]
          Argument::value("plugin-gid-map", "GID:GID:INT", "Supplemental GIDs that should be mapped in plugin jail.  Can be given more than once."),
          Argument::flag("vhost-net", "Use vhost for networking."),
          Argument::value("tap-fd",
                          "fd",
                          "File descriptor for configured tap device. A different virtual network card will be added each time this argument is given."),
          #[cfg(feature = "gpu")]
          Argument::flag("gpu", "(EXPERIMENTAL) enable virtio-gpu device"),
          #[cfg(feature = "tpm")]
          Argument::flag("software-tpm", "enable a software emulated trusted platform module device"),
          Argument::value("evdev", "PATH", "Path to an event device node. The device will be grabbed (unusable from the host) and made available to the guest with the same configuration it shows on the host"),
          Argument::value("trackpad", "PATH:WIDTH:HEIGHT", "Path to a socket from where to read trackpad input events and write status updates to, optionally followed by screen width and height (defaults to 800x1280)."),
          Argument::value("mouse", "PATH", "Path to a socket from where to read mouse input events and write status updates to."),
          Argument::value("keyboard", "PATH", "Path to a socket from where to read keyboard input events and write status updates to."),
          #[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
          Argument::flag("split-irqchip", "(EXPERIMENTAL) enable split-irqchip support"),
          Argument::short_flag('h', "help", "Print help message.")];

    let mut cfg = Config::default();
    let match_res = set_arguments(args, &arguments[..], |name, value| {
        set_argument(&mut cfg, name, value)
    })
    .and_then(|_| {
        if cfg.kernel_path.as_os_str().is_empty() && cfg.plugin.is_none() {
            return Err(argument::Error::ExpectedArgument("`KERNEL`".to_owned()));
        }
        if cfg.host_ip.is_some() || cfg.netmask.is_some() || cfg.mac_address.is_some() {
            if cfg.host_ip.is_none() {
                return Err(argument::Error::ExpectedArgument(
                    "`host_ip` missing from network config".to_owned(),
                ));
            }
            if cfg.netmask.is_none() {
                return Err(argument::Error::ExpectedArgument(
                    "`netmask` missing from network config".to_owned(),
                ));
            }
            if cfg.mac_address.is_none() {
                return Err(argument::Error::ExpectedArgument(
                    "`mac` missing from network config".to_owned(),
                ));
            }
        }
        if cfg.plugin_root.is_some() && cfg.plugin.is_none() {
            return Err(argument::Error::ExpectedArgument(
                "`plugin-root` requires `plugin`".to_owned(),
            ));
        }
        Ok(())
    });

    match match_res {
        #[cfg(feature = "plugin")]
        Ok(()) if cfg.plugin.is_some() => match plugin::run_config(cfg) {
            Ok(_) => {
                info!("crosvm and plugin have exited normally");
                Ok(())
            }
            Err(e) => {
                error!("{}", e);
                Err(())
            }
        },
        Ok(()) => match linux::run_config(cfg) {
            Ok(_) => {
                info!("crosvm has exited normally");
                Ok(())
            }
            Err(e) => {
                error!("{}", e);
                Err(())
            }
        },
        Err(argument::Error::PrintHelp) => {
            print_help("crosvm run", "KERNEL", &arguments[..]);
            Ok(())
        }
        Err(e) => {
            println!("{}", e);
            Err(())
        }
    }
}

fn vms_request(request: &VmRequest, args: std::env::Args) -> std::result::Result<(), ()> {
    let mut return_result = Ok(());
    for socket_path in args {
        match UnixSeqpacket::connect(&socket_path) {
            Ok(s) => {
                let socket = MsgSocket::<VmRequest, VmResponse>::new(s);
                if let Err(e) = socket.send(request) {
                    error!(
                        "failed to send request to socket at '{}': {}",
                        socket_path, e
                    );
                    return_result = Err(());
                    continue;
                }
                match socket.recv() {
                    Ok(response) => info!("request response was {}", response),
                    Err(e) => {
                        error!(
                            "failed to send request to socket at2 '{}': {}",
                            socket_path, e
                        );
                        return_result = Err(());
                        continue;
                    }
                }
            }
            Err(e) => {
                error!("failed to connect to socket at '{}': {}", socket_path, e);
                return_result = Err(());
            }
        }
    }

    return_result
}

fn stop_vms(args: std::env::Args) -> std::result::Result<(), ()> {
    if args.len() == 0 {
        print_help("crosvm stop", "VM_SOCKET...", &[]);
        println!("Stops the crosvm instance listening on each `VM_SOCKET` given.");
        return Err(());
    }
    vms_request(&VmRequest::Exit, args)
}

fn suspend_vms(args: std::env::Args) -> std::result::Result<(), ()> {
    if args.len() == 0 {
        print_help("crosvm suspend", "VM_SOCKET...", &[]);
        println!("Suspends the crosvm instance listening on each `VM_SOCKET` given.");
        return Err(());
    }
    vms_request(&VmRequest::Suspend, args)
}

fn resume_vms(args: std::env::Args) -> std::result::Result<(), ()> {
    if args.len() == 0 {
        print_help("crosvm resume", "VM_SOCKET...", &[]);
        println!("Resumes the crosvm instance listening on each `VM_SOCKET` given.");
        return Err(());
    }
    vms_request(&VmRequest::Resume, args)
}

fn balloon_vms(mut args: std::env::Args) -> std::result::Result<(), ()> {
    if args.len() < 2 {
        print_help("crosvm balloon", "SIZE VM_SOCKET...", &[]);
        println!("Set the ballon size of the crosvm instance to `SIZE` bytes.");
        return Err(());
    }
    let num_bytes = match args.nth(0).unwrap().parse::<u64>() {
        Ok(n) => n,
        Err(_) => {
            error!("Failed to parse number of bytes");
            return Err(());
        }
    };

    vms_request(&VmRequest::BalloonAdjust(num_bytes), args)
}

fn create_qcow2(mut args: std::env::Args) -> std::result::Result<(), ()> {
    if args.len() != 2 {
        print_help("crosvm create_qcow2", "PATH SIZE", &[]);
        println!("Create a new QCOW2 image at `PATH` of the specified `SIZE` in bytes.");
        return Err(());
    }
    let file_path = args.nth(0).unwrap();
    let size: u64 = match args.nth(0).unwrap().parse::<u64>() {
        Ok(n) => n,
        Err(_) => {
            error!("Failed to parse size of the disk.");
            return Err(());
        }
    };

    let file = OpenOptions::new()
        .create(true)
        .read(true)
        .write(true)
        .open(&file_path)
        .map_err(|e| {
            error!("Failed opening qcow file at '{}': {}", file_path, e);
        })?;

    QcowFile::new(file, size).map_err(|e| {
        error!("Failed to create qcow file at '{}': {}", file_path, e);
    })?;

    Ok(())
}

fn disk_cmd(mut args: std::env::Args) -> std::result::Result<(), ()> {
    if args.len() < 2 {
        print_help("crosvm disk", "SUBCOMMAND VM_SOCKET...", &[]);
        println!("Manage attached virtual disk devices.");
        println!("Subcommands:");
        println!("  resize DISK_INDEX NEW_SIZE VM_SOCKET");
        return Err(());
    }
    let subcommand: &str = &args.nth(0).unwrap();

    let request = match subcommand {
        "resize" => {
            let disk_index = match args.nth(0).unwrap().parse::<usize>() {
                Ok(n) => n,
                Err(_) => {
                    error!("Failed to parse disk index");
                    return Err(());
                }
            };

            let new_size = match args.nth(0).unwrap().parse::<u64>() {
                Ok(n) => n,
                Err(_) => {
                    error!("Failed to parse disk size");
                    return Err(());
                }
            };

            VmRequest::DiskResize {
                disk_index,
                new_size,
            }
        }
        _ => {
            error!("Unknown disk subcommand '{}'", subcommand);
            return Err(());
        }
    };

    vms_request(&request, args)
}

fn print_usage() {
    print_help("crosvm", "[stop|run]", &[]);
    println!("Commands:");
    println!("    stop - Stops crosvm instances via their control sockets.");
    println!("    run  - Start a new crosvm instance.");
    println!("    create_qcow2  - Create a new qcow2 disk image file.");
    println!("    disk - Manage attached virtual disk devices.")
}

fn crosvm_main() -> std::result::Result<(), ()> {
    if let Err(e) = syslog::init() {
        println!("failed to initialize syslog: {}", e);
        return Err(());
    }

    panic_hook::set_panic_hook();

    let mut args = std::env::args();
    if args.next().is_none() {
        error!("expected executable name");
        return Err(());
    }

    // Past this point, usage of exit is in danger of leaking zombie processes.
    let ret = match args.next().as_ref().map(|a| a.as_ref()) {
        None => {
            print_usage();
            Ok(())
        }
        Some("stop") => stop_vms(args),
        Some("suspend") => suspend_vms(args),
        Some("resume") => resume_vms(args),
        Some("run") => run_vm(args),
        Some("balloon") => balloon_vms(args),
        Some("create_qcow2") => create_qcow2(args),
        Some("disk") => disk_cmd(args),
        Some(c) => {
            println!("invalid subcommand: {:?}", c);
            print_usage();
            Err(())
        }
    };

    // Reap exit status from any child device processes. At this point, all devices should have been
    // dropped in the main process and told to shutdown. Try over a period of 100ms, since it may
    // take some time for the processes to shut down.
    if !wait_all_children() {
        // We gave them a chance, and it's too late.
        warn!("not all child processes have exited; sending SIGKILL");
        if let Err(e) = kill_process_group() {
            // We're now at the mercy of the OS to clean up after us.
            warn!("unable to kill all child processes: {}", e);
        }
    }

    // WARNING: Any code added after this point is not guaranteed to run
    // since we may forcibly kill this process (and its children) above.
    ret
}

fn main() {
    std::process::exit(if crosvm_main().is_ok() { 0 } else { 1 });
}