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//! A relay binary use to join the Tor network to relay anonymous communication.
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//!
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//! NOTE: This binary is still highly experimental as in in active development, not stable and
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//! without any type of guarantee of running or even working.
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//!
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//! ## Error handling
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//!
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//! We return [`anyhow::Error`] for functions whose errors will always result in an exit and don't
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//! need to be handled individually.
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//! When we do need to handle errors, functions should return a more comprehensive error type (for
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//! example one created with `thiserror`).
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// @@ begin lint list maintained by maint/add_warning @@
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#![allow(renamed_and_removed_lints)] // @@REMOVE_WHEN(ci_arti_stable)
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#![allow(unknown_lints)] // @@REMOVE_WHEN(ci_arti_nightly)
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#![warn(missing_docs)]
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#![warn(noop_method_call)]
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#![warn(unreachable_pub)]
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#![warn(clippy::all)]
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#![deny(clippy::await_holding_lock)]
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#![deny(clippy::cargo_common_metadata)]
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#![deny(clippy::cast_lossless)]
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#![deny(clippy::checked_conversions)]
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#![warn(clippy::cognitive_complexity)]
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#![deny(clippy::debug_assert_with_mut_call)]
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#![deny(clippy::exhaustive_enums)]
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#![deny(clippy::exhaustive_structs)]
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#![deny(clippy::expl_impl_clone_on_copy)]
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#![deny(clippy::fallible_impl_from)]
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#![deny(clippy::implicit_clone)]
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#![deny(clippy::large_stack_arrays)]
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#![warn(clippy::manual_ok_or)]
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#![deny(clippy::missing_docs_in_private_items)]
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#![warn(clippy::needless_borrow)]
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#![warn(clippy::needless_pass_by_value)]
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#![warn(clippy::option_option)]
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#![deny(clippy::print_stderr)]
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#![deny(clippy::print_stdout)]
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#![warn(clippy::rc_buffer)]
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#![deny(clippy::ref_option_ref)]
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#![warn(clippy::semicolon_if_nothing_returned)]
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#![warn(clippy::trait_duplication_in_bounds)]
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#![deny(clippy::unchecked_time_subtraction)]
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#![deny(clippy::unnecessary_wraps)]
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#![warn(clippy::unseparated_literal_suffix)]
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#![deny(clippy::unwrap_used)]
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#![deny(clippy::mod_module_files)]
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#![allow(clippy::let_unit_value)] // This can reasonably be done for explicitness
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#![allow(clippy::uninlined_format_args)]
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#![allow(clippy::significant_drop_in_scrutinee)] // arti/-/merge_requests/588/#note_2812945
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#![allow(clippy::result_large_err)] // temporary workaround for arti#587
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#![allow(clippy::needless_raw_string_hashes)] // complained-about code is fine, often best
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#![allow(clippy::needless_lifetimes)] // See arti#1765
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#![allow(mismatched_lifetime_syntaxes)] // temporary workaround for arti#2060
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#![allow(clippy::collapsible_if)] // See arti#2342
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#![deny(clippy::unused_async)]
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//! <!-- @@ end lint list maintained by maint/add_warning @@ -->
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mod cli;
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mod client;
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mod config;
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mod relay;
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mod tasks;
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mod util;
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use std::io::IsTerminal as _;
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use anyhow::Context;
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use clap::Parser;
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use futures::FutureExt;
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use safelog::with_safe_logging_suppressed;
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use tor_rtcompat::SpawnExt;
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use tor_rtcompat::tokio::TokioRustlsRuntime;
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use tor_rtcompat::{Runtime, ToplevelRuntime};
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use tracing::{debug, info, trace};
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use tracing_subscriber::FmtSubscriber;
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use tracing_subscriber::filter::EnvFilter;
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use tracing_subscriber::util::SubscriberInitExt;
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use crate::config::{DEFAULT_LOG_LEVEL, TorRelayConfig, base_resolver};
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use crate::relay::InertTorRelay;
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fn main() {
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    // Will exit if '--help' used or there's a parse error.
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    let cli = cli::Cli::parse();
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    if let Err(e) = main_main(cli) {
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        // TODO: Use arti_client's `HintableError` here (see `arti::main`)?
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        // TODO: Why do we suppress safe logging?
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        // TODO: Do we want to log the error?
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        // We use anyhow's error formatting here rather than `tor_error::report_and_exit` since the
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        // latter seems to omit some error info and anyhow's error formatting is nicer.
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        #[allow(clippy::print_stderr)]
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        with_safe_logging_suppressed(|| {
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            eprintln!("Error: {e:?}");
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            // The 127 is copied from `tor_error::report_and_exit`.
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            // It's unclear why 127 was chosen there.
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            std::process::exit(127);
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        });
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    }
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}
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/// The real main without the error formatting.
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fn main_main(cli: cli::Cli) -> anyhow::Result<()> {
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    // Register a basic stderr logger until we have enough info to configure the main logger.
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    // Unlike arti, we enable timestamps for this pre-config logger.
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    // TODO: Consider using timestamps with reduced-granularity (see `LogPrecision`).
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    let level: tracing::metadata::Level = cli
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        .global
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        .log_level
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        .map(Into::into)
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        .unwrap_or(DEFAULT_LOG_LEVEL);
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    let filter = EnvFilter::builder()
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        .with_default_directive(level.into())
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        .parse("")
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        .expect("empty filter directive should be trivially parsable");
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    FmtSubscriber::builder()
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        .with_env_filter(filter)
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        .with_ansi(std::io::stderr().is_terminal())
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        .with_writer(std::io::stderr)
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        .finish()
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        .init();
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    match cli.command {
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        #[allow(clippy::print_stdout)]
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        cli::Commands::BuildInfo => {
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            println!("Version: {}", env!("CARGO_PKG_VERSION"));
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            // these are set by our build script
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            println!("Features: {}", env!("BUILD_FEATURES"));
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            println!("Profile: {}", env!("BUILD_PROFILE"));
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            println!("Debug: {}", env!("BUILD_DEBUG"));
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            println!("Optimization level: {}", env!("BUILD_OPT_LEVEL"));
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            println!("Rust version: {}", env!("BUILD_RUSTC_VERSION"));
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            println!("Target triple: {}", env!("BUILD_TARGET"));
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            println!("Host triple: {}", env!("BUILD_HOST"));
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        }
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        cli::Commands::Run(args) => start_relay(args, cli.global)?,
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    }
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    Ok(())
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}
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/// Initialize and start the relay.
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// Pass by value so that we don't need to clone fields, which keeps the code simpler.
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#[allow(clippy::needless_pass_by_value)]
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fn start_relay(_args: cli::RunArgs, global_args: cli::GlobalArgs) -> anyhow::Result<()> {
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    // TODO: Warn (or exit?) if running as root; see 'arti::process::running_as_root()'.
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    let mut cfg_sources = global_args
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        .config()
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        .context("Failed to get configuration sources")?;
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    debug!(
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        "Using override options: {}",
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        util::iter_join(", ", cfg_sources.options()),
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    );
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    // A Mistrust object to use for loading our configuration.
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    // Elsewhere, we use the value _from_ the configuration.
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    let cfg_mistrust = if global_args.disable_fs_permission_checks {
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        fs_mistrust::Mistrust::new_dangerously_trust_everyone()
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    } else {
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        fs_mistrust::MistrustBuilder::default()
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            // By default, a `Mistrust` checks an environment variable.
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            // We do not (at the moment) want this behaviour for relays:
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            // https://gitlab.torproject.org/tpo/core/arti/-/merge_requests/2699#note_3147502
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            .ignore_environment()
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            .build()
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            .expect("default fs-mistrust should be buildable")
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    };
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    cfg_sources.set_mistrust(cfg_mistrust);
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    let cfg = cfg_sources
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        .load()
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        .context("Failed to load configuration sources")?;
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    let config =
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        tor_config::resolve::<TorRelayConfig>(cfg).context("Failed to resolve configuration")?;
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    // TODO: Configure a proper logger, not just a simple stderr logger.
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    // TODO: We may want this to be the global logger, but if we use arti's `setup_logging` in the
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    // future, it returns a `LogGuards` which we'd have no way of holding on to until the
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    // application exits (see https://gitlab.torproject.org/tpo/core/arti/-/issues/1791).
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    let filter = EnvFilter::builder()
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        .parse(&config.logging.console)
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        .with_context(|| {
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            format!(
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                "Failed to parse console logging directive {:?}",
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                config.logging.console,
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            )
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        })?;
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    let logger = tracing_subscriber::FmtSubscriber::builder()
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        .with_env_filter(filter)
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        .with_ansi(std::io::stderr().is_terminal())
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        .with_writer(std::io::stderr)
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        .finish();
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    let logger = tracing::Dispatch::new(logger);
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    tracing::dispatcher::with_default(&logger, || {
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        let runtime = init_runtime().context("Failed to initialize the runtime")?;
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        // Configure tor-log-ratelim early before we begin logging.
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        tor_log_ratelim::install_runtime(runtime.clone())
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            .context("Failed to initialze tor-log-ratelim")?;
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        let path_resolver = base_resolver();
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        let relay =
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            InertTorRelay::new(config, path_resolver).context("Failed to initialize the relay")?;
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        match mainloop(&runtime, run_relay(runtime.clone(), relay))? {
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            MainloopStatus::Finished(Err(e)) => Err(e),
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            MainloopStatus::CtrlC => {
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                info!("Received a ctrl-c; stopping the relay");
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                Ok(())
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            }
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        }
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    })
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}
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/// A helper to drive a future using a runtime.
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///
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/// This calls `block_on` on the runtime.
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/// The future will be cancelled on a ctrl-c event.
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fn mainloop<T: Send + 'static>(
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    runtime: &impl ToplevelRuntime,
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    fut: impl Future<Output = T> + Send + 'static,
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) -> anyhow::Result<MainloopStatus<T>> {
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    trace!("Starting runtime");
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    let rv = runtime.block_on(async {
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        // Code running in 'block_on' runs slower than in a task (in tokio at least),
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        // so the future is run on a task.
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        let mut handle = runtime
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            .spawn_with_handle(fut)
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            .context("Failed to spawn task")?
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            .fuse();
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        futures::select!(
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            // Signal handler is registered on the first poll.
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            res = tokio::signal::ctrl_c().fuse() => {
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                let () = res.context("Failed to listen for ctrl-c event")?;
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                trace!("Received a ctrl-c");
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                // Dropping the handle will cancel the task, so we do that explicitly here.
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                drop(handle);
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                Ok(MainloopStatus::CtrlC)
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            }
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            x = handle => Ok(MainloopStatus::Finished(x)),
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        )
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    });
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    trace!("Finished runtime");
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    rv
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}
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/// Run the relay.
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///
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/// This blocks until the relay stops.
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async fn run_relay<R: Runtime>(
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    runtime: R,
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    inert_relay: InertTorRelay,
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) -> anyhow::Result<void::Void> {
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    let relay = inert_relay
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        .init(runtime)
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        .await
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        .context("Failed to bootstrap")?;
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    // This blocks until end of time or an error.
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    relay.run().await
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}
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/// Initialize a runtime.
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///
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/// Any cli commands that need a runtime should call this so that we use a consistent runtime.
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fn init_runtime() -> std::io::Result<impl ToplevelRuntime> {
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    // Use the tokio runtime from tor_rtcompat unless we later find a reason to use tokio directly.
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    // See https://gitlab.torproject.org/tpo/core/arti/-/work_items/1744.
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    // Relays must use rustls as native-tls doesn't support
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    // `CertifiedConn::export_keying_material()`.
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    // Note: See comments in `tor_rtcompat::impls::rustls::RustlsProvider`
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    // about choice of default crypto provider.
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    let _idempotent_ignore =
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        rustls::crypto::CryptoProvider::install_default(rustls::crypto::ring::default_provider());
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    TokioRustlsRuntime::create()
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}
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/// The result of [`mainloop`].
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enum MainloopStatus<T> {
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    /// The result from the completed future.
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    Finished(T),
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    /// The future was cancelled due to a ctrl-c event.
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    CtrlC,
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}