crosvm_control: remove all conditional compilation

The crosvm_control library's API and ABI should not depend on crosvm
configuration options. If functionality is not available in a particular
build, the library should just provide a stub version of the function
that returns an error, rather than changing the exported symbols or
function prototypes.

BUG=None
TEST=tools/dev_container tools/presubmit
TEST=cargo build --no-default-features -p crosvm_control

Change-Id: I4428d3efe8d52a16ec78998fd83cd7d16b6b7773
Reviewed-on: https://chromium-review.googlesource.com/c/crosvm/crosvm/+/5623295
Commit-Queue: Daniel Verkamp <dverkamp@chromium.org>
Reviewed-by: Frederick Mayle <fmayle@google.com>

5 files changed, 25 insertions, 36 deletions

diff --git a/crosvm_control/src/lib.rs b/crosvm_control/src/lib.rs
index a5df661d1..0bfefc8ea 100644
--- a/crosvm_control/src/lib.rs
+++ b/crosvm_control/src/lib.rs
@@ -9,7 +9,13 @@
 //!
 //! Downstream projects rely on this library maintaining a stable API surface.
 //! Do not make changes to this library without consulting the crosvm externalization team.
-//! Email: crosvm-dev@chromium.org
+//! Email: <crosvm-dev@chromium.org>
+//!
+//! The API of this library should remain the same regardless of which crosvm features are enabled.
+//! Any missing functionality should be handled by returning an error at runtime, not conditional
+//! compilation, so that users can rely on the the same set of functions with the same prototypes
+//! regardless of how crosvm is configured.
+//!
 //! For more information see:
 //! <https://crosvm.dev/book/running_crosvm/programmatic_interaction.html#usage>
 
@@ -19,7 +25,6 @@ use std::ffi::CStr;
 use std::panic::catch_unwind;
 use std::path::Path;
 use std::path::PathBuf;
-#[cfg(any(target_os = "android", target_os = "linux"))]
 use std::time::Duration;
 
 use libc::c_char;
@@ -33,14 +38,12 @@ use vm_control::client::do_usb_attach;
 use vm_control::client::do_usb_detach;
 use vm_control::client::do_usb_list;
 use vm_control::client::handle_request;
-#[cfg(any(target_os = "android", target_os = "linux"))]
 use vm_control::client::handle_request_with_timeout;
 use vm_control::client::vms_request;
 use vm_control::BalloonControlCommand;
 use vm_control::BalloonStats;
 use vm_control::BalloonWS;
 use vm_control::DiskControlCommand;
-#[cfg(feature = "registered_events")]
 use vm_control::RegisteredEvent;
 use vm_control::SwapCommand;
 use vm_control::UsbControlAttachedDevice;
@@ -183,7 +186,6 @@ pub unsafe extern "C" fn crosvm_client_balloon_vms(
 /// Function is unsafe due to raw pointer usage - a null pointer could be passed in. Usage of
 /// !raw_pointer.is_null() checks should prevent unsafe behavior but the caller should ensure no
 /// null pointers are passed.
-#[cfg(any(target_os = "android", target_os = "linux"))]
 #[no_mangle]
 pub unsafe extern "C" fn crosvm_client_balloon_vms_wait_with_timeout(
     socket_path: *const c_char,
@@ -783,13 +785,7 @@ pub unsafe extern "C" fn crosvm_client_balloon_stats(
     stats: *mut BalloonStatsFfi,
     actual: *mut u64,
 ) -> bool {
-    crosvm_client_balloon_stats_impl(
-        socket_path,
-        #[cfg(any(target_os = "android", target_os = "linux"))]
-        None,
-        stats,
-        actual,
-    )
+    crosvm_client_balloon_stats_impl(socket_path, None, stats, actual)
 }
 
 /// See crosvm_client_balloon_stats.
@@ -799,7 +795,6 @@ pub unsafe extern "C" fn crosvm_client_balloon_stats(
 /// Function is unsafe due to raw pointer usage - a null pointer could be passed in. Usage of
 /// !raw_pointer.is_null() checks should prevent unsafe behavior but the caller should ensure no
 /// null pointers are passed.
-#[cfg(any(target_os = "android", target_os = "linux"))]
 #[no_mangle]
 pub unsafe extern "C" fn crosvm_client_balloon_stats_with_timeout(
     socket_path: *const c_char,
@@ -817,16 +812,13 @@ pub unsafe extern "C" fn crosvm_client_balloon_stats_with_timeout(
 
 fn crosvm_client_balloon_stats_impl(
     socket_path: *const c_char,
-    #[cfg(any(target_os = "android", target_os = "linux"))] timeout_ms: Option<Duration>,
+    timeout_ms: Option<Duration>,
     stats: *mut BalloonStatsFfi,
     actual: *mut u64,
 ) -> bool {
     catch_unwind(|| {
         if let Some(socket_path) = validate_socket_path(socket_path) {
             let request = &VmRequest::BalloonCommand(BalloonControlCommand::Stats {});
-            #[cfg(not(unix))]
-            let resp = handle_request(request, socket_path);
-            #[cfg(any(target_os = "android", target_os = "linux"))]
             let resp = handle_request_with_timeout(request, socket_path, timeout_ms);
             if let Ok(VmResponse::BalloonStats {
                 stats: ref balloon_stats,
@@ -989,19 +981,14 @@ pub unsafe extern "C" fn crosvm_client_balloon_working_set(
 
 /// Publically exposed version of RegisteredEvent enum, implemented as an
 /// integral newtype for FFI safety.
-#[cfg(feature = "registered_events")]
 #[repr(C)]
 #[derive(Copy, Clone, PartialEq, Eq)]
 pub struct RegisteredEventFfi(u32);
 
-#[cfg(feature = "registered_events")]
 pub const REGISTERED_EVENT_VIRTIO_BALLOON_WS_REPORT: RegisteredEventFfi = RegisteredEventFfi(0);
-#[cfg(feature = "registered_events")]
 pub const REGISTERED_EVENT_VIRTIO_BALLOON_RESIZE: RegisteredEventFfi = RegisteredEventFfi(1);
-#[cfg(feature = "registered_events")]
 pub const REGISTERED_EVENT_VIRTIO_BALLOON_OOM_DEFLATION: RegisteredEventFfi = RegisteredEventFfi(2);
 
-#[cfg(feature = "registered_events")]
 impl TryFrom<RegisteredEventFfi> for RegisteredEvent {
     type Error = &'static str;
 
@@ -1024,7 +1011,6 @@ impl TryFrom<RegisteredEventFfi> for RegisteredEvent {
 /// Function is unsafe due to raw pointer usage - a null pointer could be passed in. Usage of
 /// !raw_pointer.is_null() checks should prevent unsafe behavior but the caller should ensure no
 /// null pointers are passed.
-#[cfg(feature = "registered_events")]
 #[no_mangle]
 pub unsafe extern "C" fn crosvm_client_register_events_listener(
     socket_path: *const c_char,
@@ -1062,7 +1048,6 @@ pub unsafe extern "C" fn crosvm_client_register_events_listener(
 /// Function is unsafe due to raw pointer usage - a null pointer could be passed in. Usage of
 /// !raw_pointer.is_null() checks should prevent unsafe behavior but the caller should ensure no
 /// null pointers are passed.
-#[cfg(feature = "registered_events")]
 #[no_mangle]
 pub unsafe extern "C" fn crosvm_client_unregister_events_listener(
     socket_path: *const c_char,
@@ -1100,7 +1085,6 @@ pub unsafe extern "C" fn crosvm_client_unregister_events_listener(
 /// Function is unsafe due to raw pointer usage - a null pointer could be passed in. Usage of
 /// !raw_pointer.is_null() checks should prevent unsafe behavior but the caller should ensure no
 /// null pointers are passed.
-#[cfg(feature = "registered_events")]
 #[no_mangle]
 pub unsafe extern "C" fn crosvm_client_unregister_listener(
     socket_path: *const c_char,
diff --git a/vm_control/src/client.rs b/vm_control/src/client.rs
index 4e0bdd0a1..73577e76c 100644
--- a/vm_control/src/client.rs
+++ b/vm_control/src/client.rs
@@ -24,7 +24,6 @@ pub use crate::gpu::do_gpu_set_display_mouse_mode;
 #[cfg(feature = "gpu")]
 pub use crate::gpu::ModifyGpuResult;
 pub use crate::sys::handle_request;
-#[cfg(any(target_os = "android", target_os = "linux"))]
 pub use crate::sys::handle_request_with_timeout;
 use crate::BatControlCommand;
 use crate::BatControlResult;
diff --git a/vm_control/src/lib.rs b/vm_control/src/lib.rs
index fffccb308..b53f81c98 100644
--- a/vm_control/src/lib.rs
+++ b/vm_control/src/lib.rs
@@ -1337,19 +1337,16 @@ pub enum VmRequest {
     /// Command to Snapshot devices
     Snapshot(SnapshotCommand),
     /// Register for event notification
-    #[cfg(feature = "registered_events")]
     RegisterListener {
         socket_addr: String,
         event: RegisteredEvent,
     },
     /// Unregister for notifications for event
-    #[cfg(feature = "registered_events")]
     UnregisterListener {
         socket_addr: String,
         event: RegisteredEvent,
     },
     /// Unregister for all event notification
-    #[cfg(feature = "registered_events")]
     Unregister { socket_addr: String },
     /// Suspend VM VCPUs and Devices until resume.
     SuspendVm,
@@ -1359,7 +1356,6 @@ pub enum VmRequest {
 
 /// NOTE: when making any changes to this enum please also update
 /// RegisteredEventFfi in crosvm_control/src/lib.rs
-#[cfg(feature = "registered_events")]
 #[derive(Serialize, Deserialize, Debug, PartialEq, Eq, Hash, Clone, Copy)]
 pub enum RegisteredEvent {
     VirtioBalloonWsReport,
@@ -1367,7 +1363,6 @@ pub enum RegisteredEvent {
     VirtioBalloonOOMDeflation,
 }
 
-#[cfg(feature = "registered_events")]
 #[derive(Serialize, Deserialize, Debug)]
 pub enum RegisteredEventWithData {
     VirtioBalloonWsReport {
@@ -1378,7 +1373,6 @@ pub enum RegisteredEventWithData {
     VirtioBalloonOOMDeflation,
 }
 
-#[cfg(feature = "registered_events")]
 impl RegisteredEventWithData {
     pub fn into_event(&self) -> RegisteredEvent {
         match self {
@@ -1388,6 +1382,7 @@ impl RegisteredEventWithData {
         }
     }
 
+    #[cfg(feature = "registered_events")]
     pub fn into_proto(&self) -> registered_events::RegisteredEvent {
         match self {
             Self::VirtioBalloonWsReport {
@@ -2005,17 +2000,14 @@ impl VmRequest {
                     }
                 }
             }
-            #[cfg(feature = "registered_events")]
             VmRequest::RegisterListener {
                 socket_addr: _,
                 event: _,
             } => VmResponse::Ok,
-            #[cfg(feature = "registered_events")]
             VmRequest::UnregisterListener {
                 socket_addr: _,
                 event: _,
             } => VmResponse::Ok,
-            #[cfg(feature = "registered_events")]
             VmRequest::Unregister { socket_addr: _ } => VmResponse::Ok,
         }
     }
diff --git a/vm_control/src/sys.rs b/vm_control/src/sys.rs
index 8b868392b..29bfdb6ef 100644
--- a/vm_control/src/sys.rs
+++ b/vm_control/src/sys.rs
@@ -9,7 +9,6 @@ cfg_if::cfg_if! {
         pub use platform::{VmMemoryMappingRequest, VmMemoryMappingResponse, FsMappingRequest};
         #[cfg(feature = "gpu")]
         pub use platform::gpu::UnixDisplayMode as DisplayMode;
-        pub use platform::handle_request_with_timeout;
         #[cfg(feature = "gpu")]
         pub use platform::gpu::UnixMouseMode as MouseMode;
     } else if #[cfg(windows)] {
@@ -26,5 +25,6 @@ cfg_if::cfg_if! {
 }
 
 pub use platform::handle_request;
+pub use platform::handle_request_with_timeout;
 pub use platform::prepare_shared_memory_region;
 pub use platform::should_prepare_memory_region;
diff --git a/vm_control/src/sys/windows.rs b/vm_control/src/sys/windows.rs
index d1020b7c3..04acfa727 100644
--- a/vm_control/src/sys/windows.rs
+++ b/vm_control/src/sys/windows.rs
@@ -8,6 +8,7 @@ pub(crate) mod gpu;
 use std::io::Result;
 use std::mem::size_of;
 use std::path::Path;
+use std::time::Duration;
 
 use base::error;
 use base::named_pipes::BlockingMode;
@@ -68,6 +69,19 @@ pub fn handle_request<T: AsRef<Path> + std::fmt::Debug>(
     }
 }
 
+pub fn handle_request_with_timeout<T: AsRef<Path> + std::fmt::Debug>(
+    request: &VmRequest,
+    socket_path: T,
+    timeout: Option<Duration>,
+) -> HandleRequestResult {
+    if timeout.is_none() {
+        handle_request(request, socket_path)
+    } else {
+        error!("handle_request_with_timeout() not implemented for Windows");
+        Err(())
+    }
+}
+
 /// Send the size header first and then the protbuf message.
 ///
 /// A helper function to keep communication with service consistent across crosvm code.