main: cli: add D-Bus API related CLI options

Introduces three new CLI options, `dbus-service-name`,
`dbus-object-path` and `dbus-system-bus` to configure the DBus API.

Signed-off-by: Omer Faruk Bayram <omer.faruk@sartura.hr>

src/main.rs

@@ -19,7 +19,7 @@ use std::sync::mpsc::channel;
 use std::sync::{Arc, Mutex};
 use thiserror::Error;
 #[cfg(feature = "dbus_api")]
-use vmm::api::dbus::dbus_api_graceful_shutdown;
+use vmm::api::dbus::{dbus_api_graceful_shutdown, DBusApiOptions};
 use vmm::config;
 use vmm_sys_util::eventfd::EventFd;
 use vmm_sys_util::signal::block_signal;
@@ -59,6 +59,12 @@ enum Error {
     ParsingApiSocket(std::num::ParseIntError),
     #[error("Error parsing --event-monitor: {0}")]
     ParsingEventMonitor(option_parser::OptionParserError),
+    #[cfg(feature = "dbus_api")]
+    #[error("`--dbus-object-path` option isn't provided")]
+    MissingDBusObjectPath,
+    #[cfg(feature = "dbus_api")]
+    #[error("`--dbus-service-name` option isn't provided")]
+    MissingDBusServiceName,
     #[error("Error parsing --event-monitor: path or fd required")]
     BareEventMonitor,
     #[error("Error doing event monitor I/O: {0}")]
@@ -239,6 +245,21 @@ pub struct TopLevel {
     /// path=<path/to/a/file>|fd=<fd>
     api_socket: Option<String>,
 
+    #[cfg(feature = "dbus_api")]
+    #[argh(option, long = "dbus-service-name")]
+    /// well known name of the service
+    dbus_name: Option<String>,
+
+    #[cfg(feature = "dbus_api")]
+    #[argh(option, long = "dbus-object-path")]
+    /// object path to serve the dbus interface
+    dbus_path: Option<String>,
+
+    #[cfg(feature = "dbus_api")]
+    #[argh(switch, long = "dbus-system-bus")]
+    /// use the system bus instead of a session bus
+    dbus_system_bus: bool,
+
     #[argh(option, long = "event-monitor")]
     /// path=<path/to/a/file>|fd=<fd>
     event_monitor: Option<String>,
@@ -418,6 +439,18 @@ fn start_vmm(toplevel: TopLevel) -> Result<Option<String>, Error> {
         (None, None)
     };
 
+    #[cfg(feature = "dbus_api")]
+    let dbus_options = match (&toplevel.dbus_name, &toplevel.dbus_path) {
+        (Some(ref name), Some(ref path)) => Ok(Some(DBusApiOptions {
+            service_name: name.to_owned(),
+            object_path: path.to_owned(),
+            system_bus: toplevel.dbus_system_bus,
+        })),
+        (Some(_), None) => Err(Error::MissingDBusObjectPath),
+        (None, Some(_)) => Err(Error::MissingDBusServiceName),
+        (None, None) => Ok(None),
+    }?;
+
     if let Some(ref monitor_config) = toplevel.event_monitor {
         let mut parser = OptionParser::new();
         parser.add("path").add("fd");
@@ -519,6 +552,8 @@ fn start_vmm(toplevel: TopLevel) -> Result<Option<String>, Error> {
         vmm::VmmVersionInfo::new(env!("BUILD_VERSION"), env!("CARGO_PKG_VERSION")),
         &api_socket_path,
         api_socket_fd,
+        #[cfg(feature = "dbus_api")]
+        dbus_options,
         api_evt.try_clone().unwrap(),
         api_request_sender_clone,
         api_request_receiver,
@@ -577,7 +612,9 @@ fn start_vmm(toplevel: TopLevel) -> Result<Option<String>, Error> {
         .map_err(Error::VmmThread)?;
 
     #[cfg(feature = "dbus_api")]
-    dbus_api_graceful_shutdown(vmm_thread_handle.dbus_shutdown_chs);
+    if let Some(chs) = vmm_thread_handle.dbus_shutdown_chs {
+        dbus_api_graceful_shutdown(chs);
+    }
 
     r.map(|_| api_socket_path)
 }

vmm/src/api/dbus/mod.rs

@@ -20,6 +20,12 @@ use zbus::{dbus_interface, ConnectionBuilder};
 
 pub type DBusApiShutdownChannels = (oneshot::Sender<()>, oneshot::Receiver<()>);
 
+pub struct DBusApiOptions {
+    pub service_name: String,
+    pub object_path: String,
+    pub system_bus: bool,
+}
+
 pub struct DBusApi {
     api_notifier: EventFd,
     api_sender: futures::lock::Mutex<Sender<ApiRequest>>,
@@ -278,8 +284,8 @@ impl DBusApi {
     }
 }
 
-// TODO: add command line arguments to make this configurable
 pub fn start_dbus_thread(
+    dbus_options: DBusApiOptions,
     api_notifier: EventFd,
     api_sender: Sender<ApiRequest>,
     seccomp_action: &SeccompAction,
@@ -288,10 +294,16 @@ pub fn start_dbus_thread(
 ) -> VmmResult<(thread::JoinHandle<VmmResult<()>>, DBusApiShutdownChannels)> {
     let dbus_iface = DBusApi::new(api_notifier, api_sender);
     let connection = executor::block_on(async move {
-        ConnectionBuilder::session()?
+        let conn_builder = if dbus_options.system_bus {
+            ConnectionBuilder::system()?
+        } else {
+            ConnectionBuilder::session()?
+        };
+
+        conn_builder
             .internal_executor(false)
-            .name("org.cloudhypervisor.DBusApi")?
-            .serve_at("/org/cloudhypervisor/DBusApi", dbus_iface)?
+            .name(dbus_options.service_name)?
+            .serve_at(dbus_options.object_path, dbus_iface)?
             .build()
             .await
     })

vmm/src/lib.rs

@@ -26,7 +26,7 @@ use crate::seccomp_filters::{get_seccomp_filter, Thread};
 use crate::vm::{Error as VmError, Vm, VmState};
 use anyhow::anyhow;
 #[cfg(feature = "dbus_api")]
-use api::dbus::DBusApiShutdownChannels;
+use api::dbus::{DBusApiOptions, DBusApiShutdownChannels};
 use libc::{tcsetattr, termios, EFD_NONBLOCK, SIGINT, SIGTERM, TCSANOW};
 use memory_manager::MemoryManagerSnapshotData;
 use pci::PciBdf;
@@ -294,6 +294,7 @@ pub fn start_vmm_thread(
     vmm_version: VmmVersionInfo,
     http_path: &Option<String>,
     http_fd: Option<RawFd>,
+    #[cfg(feature = "dbus_api")] dbus_options: Option<DBusApiOptions>,
     api_event: EventFd,
     api_sender: Sender<ApiRequest>,
     api_receiver: Receiver<ApiRequest>,
@@ -357,13 +358,20 @@ pub fn start_vmm_thread(
     // The VMM thread is started, we can start the dbus thread
     // and start serving HTTP requests
     #[cfg(feature = "dbus_api")]
-    let (_, dbus_shutdown_chs) = api::start_dbus_thread(
-        api_event_clone.try_clone().map_err(Error::EventFdClone)?,
-        api_sender.clone(),
-        seccomp_action,
-        exit_event.try_clone().map_err(Error::EventFdClone)?,
-        hypervisor_type,
-    )?;
+    let dbus_shutdown_chs = match dbus_options {
+        Some(opts) => {
+            let (_, chs) = api::start_dbus_thread(
+                opts,
+                api_event_clone.try_clone().map_err(Error::EventFdClone)?,
+                api_sender.clone(),
+                seccomp_action,
+                exit_event.try_clone().map_err(Error::EventFdClone)?,
+                hypervisor_type,
+            )?;
+            Some(chs)
+        }
+        None => None,
+    };
 
     if let Some(http_path) = http_path {
         api::start_http_path_thread(
@@ -432,7 +440,7 @@ impl VmmVersionInfo {
 pub struct VmmThreadHandle {
     pub thread_handle: thread::JoinHandle<Result<()>>,
     #[cfg(feature = "dbus_api")]
-    pub dbus_shutdown_chs: DBusApiShutdownChannels,
+    pub dbus_shutdown_chs: Option<DBusApiShutdownChannels>,
 }
 
 pub struct Vmm {