fuchsia_scheduler/
lib.rs

1// Copyright 2024 The Fuchsia Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5use anyhow::{Context, Error};
6use fidl_fuchsia_scheduler::{
7    RoleManagerMarker, RoleManagerSetRoleRequest, RoleManagerSynchronousProxy, RoleName, RoleTarget,
8};
9use fuchsia_component::client::connect_to_protocol_sync;
10use fuchsia_sync::RwLock;
11use std::sync::Arc;
12use zx::{HandleBased, MonotonicInstant, Rights, Status, Thread, Vmar};
13
14static ROLE_MANAGER: RwLock<Option<Arc<RoleManagerSynchronousProxy>>> = RwLock::new(None);
15
16fn connect() -> Result<Arc<RoleManagerSynchronousProxy>, Error> {
17    // If the proxy has been connected already, return.
18    if let Some(ref proxy) = *ROLE_MANAGER.read() {
19        return Ok(Arc::clone(&proxy));
20    }
21
22    // Acquire the write lock and make sure no other thread connected to the proxy while we
23    // were waiting on the write lock.
24    let mut proxy = ROLE_MANAGER.write();
25    if let Some(ref proxy) = *proxy {
26        return Ok(Arc::clone(&proxy));
27    }
28
29    // Connect to the synchronous proxy.
30    let p = Arc::new(connect_to_protocol_sync::<RoleManagerMarker>()?);
31    *proxy = Some(Arc::clone(&p));
32    Ok(p)
33}
34
35fn disconnect() {
36    // Drop our connection to the proxy by setting it to None.
37    let mut proxy = ROLE_MANAGER.write();
38    *proxy = None;
39}
40
41fn set_role_for_target(target: RoleTarget, role_name: &str) -> Result<(), Error> {
42    let role_manager = connect()?;
43    let request = RoleManagerSetRoleRequest {
44        target: Some(target),
45        role: Some(RoleName { role: role_name.to_string() }),
46        ..Default::default()
47    };
48    let _ = role_manager
49        .set_role(request, MonotonicInstant::INFINITE)
50        .context("fuchsia.scheduler.RoleManager::SetRole failed")
51        .and_then(|result| {
52            match result {
53                Ok(_) => Ok(()),
54                Err(status) => {
55                    // If the server responded with ZX_ERR_PEER_CLOSED, mark the synchronous proxy as
56                    // disconnected so future invocations of this function reconnect to the RoleManager.
57                    if status == Status::PEER_CLOSED.into_raw() {
58                        disconnect();
59                    }
60                    Status::ok(status).context(format!(
61                        "fuchsia.scheduler.RoleManager::SetRole returned error: {:?}",
62                        status
63                    ))
64                }
65            }
66        })?;
67    Ok(())
68}
69
70pub fn set_role_for_thread(thread: &Thread, role_name: &str) -> Result<(), Error> {
71    let thread = thread
72        .duplicate_handle(Rights::SAME_RIGHTS)
73        .context("Failed to duplicate thread handle")?;
74    set_role_for_target(RoleTarget::Thread(thread), role_name)
75}
76
77pub fn set_role_for_this_thread(role_name: &str) -> Result<(), Error> {
78    set_role_for_thread(&fuchsia_runtime::thread_self(), role_name)
79}
80
81pub fn set_role_for_vmar(vmar: &Vmar, role_name: &str) -> Result<(), Error> {
82    let vmar =
83        vmar.duplicate_handle(Rights::SAME_RIGHTS).context("Failed to duplicate vmar handle")?;
84    set_role_for_target(RoleTarget::Vmar(vmar), role_name)
85}
86
87pub fn set_role_for_root_vmar(role_name: &str) -> Result<(), Error> {
88    set_role_for_vmar(&fuchsia_runtime::vmar_root_self(), role_name)
89}
fuchsia_scheduler/lib.rs

fuchsia_scheduler/
lib.rs
