broker_ipc: add crate

Adds the broker_ipc crate, which is used for communication & setup tasks
shared between the broker (Windows orchestrator for crosvm & vhost-user
devices) and all other crosvm processes.

BUG=b:232318124
TEST=builds

Change-Id: I17d529305dd348a50574e6c3c082808e97ffff45
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosvm/+/3648474
Reviewed-by: Dennis Kempin <denniskempin@google.com>
Tested-by: kokoro <noreply+kokoro@google.com>
Commit-Queue: Noah Gold <nkgold@google.com>

Cargo.toml

@@ -47,6 +47,7 @@ members = [
     "argh_helpers",
     "base",
     "bit_field",
+    "broker_ipc",
     "cros_async",
     "crosvm-fuzz",
     "crosvm_control",
@@ -154,6 +155,7 @@ assertions = { path = "common/assertions" }
 audio_streams = "*"
 base = "*"
 bit_field = { path = "bit_field" }
+broker_ipc = { path = "broker_ipc" }
 cfg-if = "1.0.0"
 crosvm_plugin = { path = "crosvm_plugin", optional = true }
 data_model = "*"

broker_ipc/Cargo.toml

@@ -0,0 +1,12 @@
+[package]
+name = "broker_ipc"
+authors = ["The Chromium OS Authors"]
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+anyhow = "1.0.32"
+base = { path = "../base" }
+serde = { version = "1", features = [ "derive" ] }
+metrics = { path = "../metrics" }
+

broker_ipc/src/generic.rs

@@ -0,0 +1,32 @@
+// Copyright 2022 The Chromium OS Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+//! Generic implementation of product specific functions that are called on child process
+//! initialization.
+
+use crate::{log_file_from_path, CommonChildStartupArgs};
+use base::Tube;
+use serde::{Deserialize, Serialize};
+use std::path::PathBuf;
+
+#[derive(Serialize, Deserialize)]
+pub struct ProductAttributes {}
+
+impl CommonChildStartupArgs {
+    pub fn new(syslog_path: Option<PathBuf>, metrics_tube: Option<Tube>) -> anyhow::Result<Self> {
+        Ok(Self {
+            product_attrs: ProductAttributes {},
+            metrics_tube,
+            syslog_file: log_file_from_path(syslog_path)?,
+        })
+    }
+}
+
+pub(crate) fn init_child_crash_reporting(_attrs: &ProductAttributes) {
+    // Do nothing. Crash reporting is implemented by a specific product.
+}
+
+pub(crate) fn product_child_setup(_attrs: &ProductAttributes) -> anyhow::Result<()> {
+    Ok(())
+}

broker_ipc/src/lib.rs

@@ -0,0 +1,78 @@
+// Copyright 2022 The Chromium OS Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+//! Contains shared code between the broker & its children, specifically any IPC messages or common
+//! bootstrapping code.
+
+use anyhow::Context;
+use base::{enable_high_res_timers, syslog, FromRawDescriptor, IntoRawDescriptor, SafeDescriptor};
+use base::{EnabledHighResTimer, Tube};
+use serde::{Deserialize, Serialize};
+use std::fs::{File, OpenOptions};
+
+mod generic;
+use generic as product;
+
+use product::{init_child_crash_reporting, product_child_setup, ProductAttributes};
+
+use std::path::PathBuf;
+
+/// Arguments that are common to all devices & helper processes.
+#[derive(Serialize, Deserialize)]
+pub struct CommonChildStartupArgs {
+    syslog_file: Option<SafeDescriptor>,
+    metrics_tube: Option<Tube>,
+    product_attrs: ProductAttributes,
+}
+
+pub struct ChildLifecycleCleanup {
+    _timer_resolution: Box<dyn EnabledHighResTimer>,
+}
+
+/// Initializes crash reporting, metrics, logging, and product specific features
+/// for a process.
+///
+/// Returns a value that should be dropped when the process exits.
+pub fn common_child_setup(args: CommonChildStartupArgs) -> anyhow::Result<ChildLifecycleCleanup> {
+    // Crash reporting should start as early as possible, in case other startup tasks fail.
+    init_child_crash_reporting(&args.product_attrs);
+
+    let mut cfg = syslog::LogConfig::default();
+    if let Some(log_file_descriptor) = args.syslog_file {
+        // Safe because we are taking ownership of a SafeDescriptor.
+        let log_file =
+            unsafe { File::from_raw_descriptor(log_file_descriptor.into_raw_descriptor()) };
+        cfg.pipe = Some(Box::new(log_file));
+        cfg.stderr = false;
+    } else {
+        cfg.stderr = true;
+    }
+    syslog::init_with(cfg)?;
+
+    // Initialize anything product specific.
+    product_child_setup(&args.product_attrs)?;
+
+    if let Some(metrics_tube) = args.metrics_tube {
+        metrics::initialize(metrics_tube);
+    }
+
+    let timer_resolution = enable_high_res_timers().context("failed to enable high res timer")?;
+
+    Ok(ChildLifecycleCleanup {
+        _timer_resolution: timer_resolution,
+    })
+}
+
+pub(crate) fn log_file_from_path(path: Option<PathBuf>) -> anyhow::Result<Option<SafeDescriptor>> {
+    Ok(match path {
+        Some(path) => Some(SafeDescriptor::from(
+            OpenOptions::new()
+                .append(true)
+                .create(true)
+                .open(path.as_path())
+                .context(format!("failed to open log file {}", path.display()))?,
+        )),
+        None => None,
+    })
+}