elf_runner/
runtime_dir.rs

1// Copyright 2021 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 fidl::endpoints::ServerEnd;
6use fidl_fuchsia_io as fio;
7use std::sync::Arc;
8use vfs::directory::entry_container::Directory;
9use vfs::directory::helper::DirectlyMutable;
10use vfs::directory::immutable::simple as pfs;
11use vfs::execution_scope::ExecutionScope;
12use vfs::file::vmo::read_only;
13use vfs::object_request::ToObjectRequest as _;
14use vfs::tree_builder::TreeBuilder;
15
16// Simple directory type which is used to implement `ComponentStartInfo.runtime_directory`.
17pub struct RuntimeDirectory(Arc<pfs::Simple>);
18
19impl RuntimeDirectory {
20    pub fn add_process_id(&self, process_id: u64) {
21        self.elf_dir()
22            .add_entry("process_id", read_only(process_id.to_string()))
23            .expect("failed to add process_id");
24    }
25
26    pub fn add_process_start_time(&self, process_start_time: i64) {
27        self.elf_dir()
28            .add_entry("process_start_time", read_only(process_start_time.to_string()))
29            .expect("failed to add process_start_time");
30    }
31
32    pub fn add_process_start_time_utc_estimate(&self, process_start_time_utc_estimate: String) {
33        self.elf_dir()
34            .add_entry(
35                "process_start_time_utc_estimate",
36                read_only(process_start_time_utc_estimate),
37            )
38            .expect("failed to add process_start_time_utc_estimate");
39    }
40
41    // Create an empty runtime directory, for test purpose only.
42    #[cfg(test)]
43    pub fn empty() -> Self {
44        let mut empty = TreeBuilder::empty_dir();
45        empty.add_empty_dir(["elf"]).expect("failed to add elf directory");
46        RuntimeDirectory(empty.build())
47    }
48
49    fn elf_dir(&self) -> Arc<pfs::Simple> {
50        self.0
51            .get_entry("elf")
52            .expect("elf directory should be present")
53            .into_any()
54            .downcast::<pfs::Simple>()
55            .expect("could not downcast elf to a directory")
56    }
57}
58
59pub struct RuntimeDirBuilder {
60    args: Vec<String>,
61    job_id: Option<u64>,
62    server_end: ServerEnd<fio::NodeMarker>,
63}
64
65impl RuntimeDirBuilder {
66    pub fn new(server_end: ServerEnd<fio::DirectoryMarker>) -> Self {
67        // Transform the server end to speak Node protocol only
68        let server_end = ServerEnd::<fio::NodeMarker>::new(server_end.into_channel());
69        Self { args: vec![], job_id: None, server_end }
70    }
71
72    pub fn args(mut self, args: Vec<String>) -> Self {
73        self.args = args;
74        self
75    }
76
77    pub fn job_id(mut self, job_id: u64) -> Self {
78        self.job_id = Some(job_id);
79        self
80    }
81
82    pub fn serve(mut self) -> RuntimeDirectory {
83        // Create the runtime tree structure
84        //
85        // runtime
86        // |- args
87        // |  |- 0
88        // |  |- 1
89        // |  \- ...
90        // \- elf
91        //    |- job_id
92        //    \- process_id
93        let mut runtime_tree_builder = TreeBuilder::empty_dir();
94        let mut count: u32 = 0;
95        for arg in self.args.drain(..) {
96            runtime_tree_builder
97                .add_entry(["args", &count.to_string()], read_only(arg))
98                .expect("Failed to add arg to runtime directory");
99            count += 1;
100        }
101
102        // Always add the "elf" directory so we can add process information later.
103        runtime_tree_builder.add_empty_dir(["elf"]).expect("failed to add elf directory");
104
105        if let Some(job_id) = self.job_id {
106            runtime_tree_builder
107                .add_entry(["elf", "job_id"], read_only(job_id.to_string()))
108                .expect("Failed to add job_id to runtime/elf directory");
109        }
110
111        let runtime_directory = runtime_tree_builder.build();
112
113        const SERVE_FLAGS: fio::Flags = fio::PERM_READABLE.union(fio::PERM_WRITABLE);
114
115        // Serve the runtime directory
116        let object_request = SERVE_FLAGS.to_object_request(self.server_end.into_channel());
117        let dir = runtime_directory.clone();
118        object_request.handle(|request| {
119            dir.open3(ExecutionScope::new(), vfs::Path::dot(), SERVE_FLAGS, request)
120        });
121        RuntimeDirectory(runtime_directory)
122    }
123}
elf_runner/runtime_dir.rs

elf_runner/
runtime_dir.rs
