[refactor](trx-rs): remove shared-library plugin system

Drop the plugin loading infrastructure (libloading-based dynamic .so/.dylib/.dll
loading) from both trx-server and trx-client. The feature was unused and posed an
unnecessary security risk by executing arbitrary native code from disk.

Removed:
- src/trx-app/src/plugins.rs (plugin discovery, validation, FFI registration)
- examples/trx-plugin-example/ (cdylib example plugin)
- libloading dependency from trx-app
- load_backend_plugins / load_frontend_plugins calls from server and client
- Plugin documentation from README.md and CLAUDE.md

https://claude.ai/code/session_01DTEUpz3XPUeWmz74NeaFgb
Signed-off-by: Claude <noreply@anthropic.com>

CLAUDE.md

@@ -88,10 +88,6 @@ The rig controller (`src/trx-core/src/rig/controller/`) is the central state man
 
 Signal decoders run as background tasks in `trx-server`, consuming decoded audio. `trx-ftx` provides the FT8/FT4/FT2 decoder in pure Rust. Decoded frames can be forwarded to PSKReporter and APRS-IS (IGate) uplinks, or logged via `trx-decode-log`.
 
-### Plugin system
-
-Both `trx-server` and `trx-client` can load shared-library plugins exporting a `trx_register` symbol. Search paths: `./plugins`, `~/.config/trx-rs/plugins`, `TRX_PLUGIN_DIRS` env var.
-
 ## Commit Format
 
 ```

Cargo.lock

@@ -2546,7 +2546,6 @@ name = "trx-app"
 version = "0.1.0"
 dependencies = [
  "dirs",
- "libloading",
  "serde",
  "thiserror 2.0.17",
  "toml",

README.md

@@ -161,16 +161,6 @@ Audio is transported as Opus between server, client, and browser.
 - `trx-client` relays audio to the HTTP frontend
 - Browsers connect over `/audio`
 
-## Plugins
-
-Both binaries can discover shared-library plugins through:
-
-- `./plugins`
-- `~/.config/trx-rs/plugins`
-- `TRX_PLUGIN_DIRS`
-
-See [`examples/trx-plugin-example/README.md`](examples/trx-plugin-example/README.md).
-
 ## Documentation
 
 - [User Manual](docs/User-Manual.md): configuration, features, and usage

examples/trx-plugin-example/Cargo.toml

@@ -1,18 +0,0 @@
-# SPDX-FileCopyrightText: 2026 Stan Grams <sjg@haxx.space>
-#
-# SPDX-License-Identifier: BSD-2-Clause
-
-[package]
-name = "trx-plugin-example"
-version = "0.1.0"
-edition = "2021"
-
-[lib]
-crate-type = ["cdylib"]
-
-[dependencies]
-trx-backend = { path = "../../src/trx-server/trx-backend" }
-trx-core = { path = "../../src/trx-core" }
-trx-frontend = { path = "../../src/trx-client/trx-frontend" }
-tokio = { workspace = true, features = ["full"] }
-tracing = { workspace = true }

examples/trx-plugin-example/README.md

@@ -1,19 +0,0 @@
-# trx-plugin-example
-
-This is a minimal shared-library plugin that registers a backend and frontend.
-The backend is a stub that returns an error; the frontend is a no-op spawner.
-
-Build:
-
-```bash
-cargo build -p trx-plugin-example --release
-```
-
-Install (example):
-
-```bash
-mkdir -p plugins
-cp target/release/libtrx_plugin_example.* plugins/
-```
-
-Run `trx-server` or `trx-client` with `TRX_PLUGIN_DIRS=./plugins` to discover the plugin.

examples/trx-plugin-example/src/lib.rs

@@ -1,50 +0,0 @@
-// SPDX-FileCopyrightText: 2026 Stan Grams <sjg@haxx.space>
-//
-// SPDX-License-Identifier: BSD-2-Clause
-
-use std::net::SocketAddr;
-
-use tokio::sync::{mpsc, watch};
-use tokio::task::JoinHandle;
-use tracing::info;
-
-use trx_backend::{RegistrationContext, RigAccess};
-use trx_core::{DynResult, RigRequest, RigState};
-use trx_frontend::{FrontendRuntimeContext, FrontendSpawner, FrontendRegistrationContext};
-
-const BACKEND_NAME: &str = "example";
-const FRONTEND_NAME: &str = "example-frontend";
-
-/// Entry point called by trx-server when the plugin is loaded.
-#[no_mangle]
-pub extern "C" fn trx_register_backend(context: *mut std::ffi::c_void) {
-    let context = unsafe { &mut *(context as *mut RegistrationContext) };
-    context.register_backend(BACKEND_NAME, example_backend_factory);
-}
-
-/// Entry point called by trx-client when the plugin is loaded.
-#[no_mangle]
-pub extern "C" fn trx_register_frontend(context: *mut std::ffi::c_void) {
-    let context = unsafe { &mut *(context as *mut FrontendRegistrationContext) };
-    context.register_frontend(FRONTEND_NAME, ExampleFrontend::spawn_frontend);
-}
-
-fn example_backend_factory(_access: RigAccess) -> DynResult<Box<dyn trx_core::rig::RigCat>> {
-    Err("example plugin backend not implemented".into())
-}
-
-struct ExampleFrontend;
-
-impl FrontendSpawner for ExampleFrontend {
-    fn spawn_frontend(
-        _state_rx: watch::Receiver<RigState>,
-        _rig_tx: mpsc::Sender<RigRequest>,
-        _callsign: Option<String>,
-        listen_addr: SocketAddr,
-        _context: std::sync::Arc<FrontendRuntimeContext>,
-    ) -> JoinHandle<()> {
-        tokio::spawn(async move {
-            info!("example frontend loaded at {} (no-op)", listen_addr);
-        })
-    }
-}

src/trx-app/Cargo.toml

@@ -14,5 +14,4 @@ toml = { workspace = true }
 tracing = { workspace = true }
 tracing-subscriber = { workspace = true }
 dirs = "6"
-libloading = "0.8"
 thiserror = "2"

src/trx-app/src/lib.rs

@@ -4,10 +4,8 @@
 
 pub mod config;
 pub mod logging;
-pub mod plugins;
 pub mod util;
 
 pub use config::{ConfigError, ConfigFile};
 pub use logging::init_logging;
-pub use plugins::{load_backend_plugins, load_frontend_plugins};
 pub use util::normalize_name;

src/trx-app/src/plugins.rs

@@ -1,189 +0,0 @@
-// SPDX-FileCopyrightText: 2026 Stan Grams <sjg@haxx.space>
-//
-// SPDX-License-Identifier: BSD-2-Clause
-
-use std::ffi::OsStr;
-use std::path::{Path, PathBuf};
-use std::ptr::NonNull;
-
-use libloading::{Library, Symbol};
-use tracing::{info, warn};
-
-/// Environment variable to disable plugin loading entirely.
-const PLUGIN_DISABLE_ENV: &str = "TRX_PLUGINS_DISABLED";
-
-const PLUGIN_ENV: &str = "TRX_PLUGIN_DIRS";
-const BACKEND_ENTRYPOINT: &str = "trx_register_backend";
-const FRONTEND_ENTRYPOINT: &str = "trx_register_frontend";
-
-#[cfg(windows)]
-const PATH_SEPARATOR: char = ';';
-#[cfg(not(windows))]
-const PATH_SEPARATOR: char = ':';
-
-#[cfg(windows)]
-const PLUGIN_EXTENSIONS: &[&str] = &["dll"];
-#[cfg(target_os = "macos")]
-const PLUGIN_EXTENSIONS: &[&str] = &["dylib"];
-#[cfg(all(unix, not(target_os = "macos")))]
-const PLUGIN_EXTENSIONS: &[&str] = &["so"];
-
-pub fn load_backend_plugins(context: NonNull<std::ffi::c_void>) -> Vec<Library> {
-    load_plugins_for_entrypoint(BACKEND_ENTRYPOINT, context)
-}
-
-pub fn load_frontend_plugins(context: NonNull<std::ffi::c_void>) -> Vec<Library> {
-    load_plugins_for_entrypoint(FRONTEND_ENTRYPOINT, context)
-}
-
-fn load_plugins_for_entrypoint(
-    entrypoint: &str,
-    context: NonNull<std::ffi::c_void>,
-) -> Vec<Library> {
-    // Allow disabling plugin loading entirely via environment variable.
-    if std::env::var(PLUGIN_DISABLE_ENV).is_ok() {
-        info!("Plugin loading disabled via {}", PLUGIN_DISABLE_ENV);
-        return Vec::new();
-    }
-
-    let mut libraries = Vec::new();
-    let search_paths = plugin_search_paths();
-
-    if search_paths.is_empty() {
-        return libraries;
-    }
-
-    info!("Plugin search paths: {:?}", search_paths);
-
-    for path in search_paths {
-        if let Err(err) = load_plugins_from_dir(&path, entrypoint, context, &mut libraries) {
-            warn!("Plugin scan failed for {:?}: {}", path, err);
-        }
-    }
-
-    libraries
-}
-
-fn load_plugins_from_dir(
-    path: &Path,
-    entrypoint: &str,
-    context: NonNull<std::ffi::c_void>,
-    libraries: &mut Vec<Library>,
-) -> std::io::Result<()> {
-    if !path.exists() {
-        return Ok(());
-    }
-
-    for entry in std::fs::read_dir(path)? {
-        let entry = entry?;
-        let path = entry.path();
-        if !path.is_file() {
-            continue;
-        }
-        if !is_plugin_file(&path) {
-            continue;
-        }
-
-        // Validate file permissions before loading.
-        if !validate_plugin_file(&path) {
-            continue;
-        }
-
-        unsafe {
-            match Library::new(&path) {
-                Ok(lib) => {
-                    if let Err(err) = register_library(&lib, &path, entrypoint, context) {
-                        warn!("Plugin {:?} failed to register: {}", path, err);
-                        continue;
-                    }
-                    info!("Loaded plugin {:?}", path);
-                    libraries.push(lib);
-                }
-                Err(err) => {
-                    warn!("Failed to load plugin {:?}: {}", path, err);
-                }
-            }
-        }
-    }
-
-    Ok(())
-}
-
-unsafe fn register_library(
-    lib: &Library,
-    path: &Path,
-    entrypoint: &str,
-    context: NonNull<std::ffi::c_void>,
-) -> Result<(), String> {
-    let entry: Symbol<unsafe extern "C" fn(*mut std::ffi::c_void)> = lib
-        .get(entrypoint.as_bytes())
-        .map_err(|e| format!("missing entrypoint {}: {}", entrypoint, e))?;
-    entry(context.as_ptr());
-    info!("Registered plugin {:?}", path);
-    Ok(())
-}
-
-fn plugin_search_paths() -> Vec<PathBuf> {
-    let mut paths = Vec::new();
-
-    if let Ok(env_paths) = std::env::var(PLUGIN_ENV) {
-        for raw in env_paths.split(PATH_SEPARATOR) {
-            if raw.trim().is_empty() {
-                continue;
-            }
-            paths.push(PathBuf::from(raw));
-        }
-    }
-
-    paths.push(PathBuf::from("plugins"));
-
-    if let Some(config_dir) = dirs::config_dir() {
-        paths.push(config_dir.join("trx-rs").join("plugins"));
-    }
-
-    paths
-}
-
-/// Validate plugin file before loading: check ownership and permissions.
-///
-/// On Unix, reject files that are world-writable (mode & 0o002) to prevent
-/// loading tampered libraries.  On non-Unix platforms, always accept.
-fn validate_plugin_file(path: &Path) -> bool {
-    #[cfg(unix)]
-    {
-        use std::os::unix::fs::MetadataExt;
-        match std::fs::metadata(path) {
-            Ok(meta) => {
-                let mode = meta.mode();
-                if mode & 0o002 != 0 {
-                    warn!(
-                        "Skipping world-writable plugin {:?} (mode {:o})",
-                        path, mode
-                    );
-                    return false;
-                }
-                true
-            }
-            Err(e) => {
-                warn!("Cannot stat plugin {:?}: {}", path, e);
-                false
-            }
-        }
-    }
-    #[cfg(not(unix))]
-    {
-        let _ = path;
-        true
-    }
-}
-
-fn is_plugin_file(path: &Path) -> bool {
-    path.extension()
-        .and_then(OsStr::to_str)
-        .map(|ext| {
-            PLUGIN_EXTENSIONS
-                .iter()
-                .any(|e| ext.eq_ignore_ascii_case(e))
-        })
-        .unwrap_or(false)
-}

src/trx-client/src/main.rs

@@ -10,7 +10,6 @@ mod remote_client;
 use std::collections::HashMap;
 use std::net::{IpAddr, SocketAddr};
 use std::path::PathBuf;
-use std::ptr::NonNull;
 use std::time::Duration;
 
 use bytes::Bytes;
@@ -20,7 +19,7 @@ use tokio::sync::{broadcast, mpsc, watch};
 use tokio::task::JoinHandle;
 use tracing::{error, info};
 
-use trx_app::{init_logging, load_frontend_plugins, normalize_name};
+use trx_app::{init_logging, normalize_name};
 use trx_core::audio::AudioStreamInfo;
 
 use trx_core::decode::DecodedMessage;
@@ -147,9 +146,6 @@ async fn async_init() -> DynResult<AppState> {
 
     init_logging(cfg.general.log_level.as_deref());
 
-    let frontend_ctx_ptr = NonNull::from(&mut frontend_reg_ctx).cast();
-    let _plugin_libs = load_frontend_plugins(frontend_ctx_ptr);
-
     if let Some(ref path) = config_path {
         info!("Loaded configuration from {}", path.display());
     }

src/trx-server/src/main.rs

@@ -14,7 +14,6 @@ use std::collections::HashMap;
 use std::collections::HashSet;
 use std::net::{IpAddr, SocketAddr};
 use std::path::PathBuf;
-use std::ptr::NonNull;
 use std::sync::Arc;
 use std::time::Duration;
 
@@ -27,7 +26,7 @@ use tracing::{error, info, warn};
 
 use trx_core::audio::AudioStreamInfo;
 
-use trx_app::{init_logging, load_backend_plugins, normalize_name};
+use trx_app::{init_logging, normalize_name};
 use trx_backend::{register_builtin_backends_on, RegistrationContext, RigAccess};
 use trx_core::rig::controller::{AdaptivePolling, ExponentialBackoff};
 use trx_core::rig::request::RigRequest;
@@ -854,9 +853,6 @@ async fn main() -> DynResult<()> {
 
     init_logging(cfg.general.log_level.as_deref());
 
-    let bootstrap_ctx_ptr = NonNull::from(&mut bootstrap_ctx).cast();
-    let _plugin_libs = load_backend_plugins(bootstrap_ctx_ptr);
-
     if let Some(ref path) = config_path {
         info!("Loaded configuration from {}", path.display());
     }