builtins/
tracing_resource.rs

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1// Copyright 2025 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::{format_err, Error};
6use fidl_fuchsia_kernel as fkernel;
7use futures::prelude::*;
8use std::sync::Arc;
9use zx::{self as zx, HandleBased, Resource};
10
11/// An implementation of fuchsia.kernel.TracingResource protocol.
12pub struct TracingResource {
13    resource: Resource,
14}
15
16impl TracingResource {
17    /// `resource` must be the tracing resource.
18    pub fn new(resource: Resource) -> Result<Arc<Self>, Error> {
19        let resource_info = resource.info()?;
20        if resource_info.kind != zx::sys::ZX_RSRC_KIND_SYSTEM
21            || resource_info.base != zx::sys::ZX_RSRC_SYSTEM_TRACING_BASE
22            || resource_info.size != 1
23        {
24            return Err(format_err!("Tracing resource not available."));
25        }
26        Ok(Arc::new(Self { resource }))
27    }
28
29    pub async fn serve(
30        self: Arc<Self>,
31        mut stream: fkernel::TracingResourceRequestStream,
32    ) -> Result<(), Error> {
33        while let Some(fkernel::TracingResourceRequest::Get { responder }) =
34            stream.try_next().await?
35        {
36            responder.send(self.resource.duplicate_handle(zx::Rights::SAME_RIGHTS)?)?;
37        }
38        Ok(())
39    }
40}
41
42#[cfg(test)]
43mod tests {
44    use super::*;
45    use fuchsia_component::client::connect_to_protocol;
46    use {fidl_fuchsia_kernel as fkernel, fuchsia_async as fasync};
47
48    async fn get_tracing_resource() -> Result<Resource, Error> {
49        let tracing_resource_provider = connect_to_protocol::<fkernel::TracingResourceMarker>()?;
50        let tracing_resource_handle = tracing_resource_provider.get().await?;
51        Ok(Resource::from(tracing_resource_handle))
52    }
53
54    async fn serve_tracing_resource() -> Result<fkernel::TracingResourceProxy, Error> {
55        let tracing_resource = get_tracing_resource().await?;
56
57        let (proxy, stream) =
58            fidl::endpoints::create_proxy_and_stream::<fkernel::TracingResourceMarker>();
59        fasync::Task::local(
60            TracingResource::new(tracing_resource)
61                .unwrap_or_else(|e| panic!("Error while creating tracing resource service: {}", e))
62                .serve(stream)
63                .unwrap_or_else(|e| panic!("Error while serving tracing resource service: {}", e)),
64        )
65        .detach();
66        Ok(proxy)
67    }
68
69    #[fuchsia::test]
70    async fn kind_type_is_tracing() -> Result<(), Error> {
71        let tracing_resource_provider = serve_tracing_resource().await?;
72        let tracing_resource: Resource = tracing_resource_provider.get().await?;
73        let resource_info = tracing_resource.info()?;
74        assert_eq!(resource_info.kind, zx::sys::ZX_RSRC_KIND_SYSTEM);
75        assert_eq!(resource_info.base, zx::sys::ZX_RSRC_SYSTEM_TRACING_BASE);
76        assert_eq!(resource_info.size, 1);
77        Ok(())
78    }
79}
builtins/tracing_resource.rs

builtins/
tracing_resource.rs
