Add IPC config subcommand

This patch adds a new mechanism for changing configuration options
without editing the configuration file, by sending options to running
instances through `alacritty msg`.

Each window will load Alacritty's configuration file by default and then
accept IPC messages for config updates using the `alacritty msg config`
subcommand. By default all windows will be updated, individual windows
can be addressed using `alacritty msg config --window-id
"$ALACRITTY_WINDOW_ID"`.

Each option will replace the config's current value and cannot be reset
until Alacritty is restarted or the option is overwritten with a new
value.

Configuration options are passed in the format `field.subfield=value`,
where `value` is interpreted as yaml.

Closes #472.

32 files changed, 630 insertions, 165 deletions

diff --git a/Cargo.lock b/Cargo.lock
index 06c70622..c786c9a4 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -18,6 +18,7 @@ checksum = "aae1277d39aeec15cb388266ecc24b11c80469deae6067e17a1a7aa9e5c1f234"
 name = "alacritty"
 version = "0.11.0-dev"
 dependencies = [
+ "alacritty_config",
  "alacritty_config_derive",
  "alacritty_terminal",
  "bitflags",
@@ -50,9 +51,19 @@ dependencies = [
 ]
 
 [[package]]
+name = "alacritty_config"
+version = "0.1.0"
+dependencies = [
+ "log",
+ "serde",
+ "serde_yaml",
+]
+
+[[package]]
 name = "alacritty_config_derive"
 version = "0.1.0"
 dependencies = [
+ "alacritty_config",
  "log",
  "proc-macro2",
  "quote",
@@ -65,6 +76,7 @@ dependencies = [
 name = "alacritty_terminal"
 version = "0.17.0-dev"
 dependencies = [
+ "alacritty_config",
  "alacritty_config_derive",
  "base64",
  "bitflags",
diff --git a/Cargo.toml b/Cargo.toml
index 7a6dec80..aad21557 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -2,6 +2,7 @@
 members = [
     "alacritty",
     "alacritty_terminal",
+    "alacritty_config",
     "alacritty_config_derive",
 ]
 
diff --git a/alacritty/Cargo.toml b/alacritty/Cargo.toml
index 989f0a83..9e858d70 100644
--- a/alacritty/Cargo.toml
+++ b/alacritty/Cargo.toml
@@ -18,8 +18,12 @@ default-features = false
 path = "../alacritty_config_derive"
 version = "0.1.0"
 
+[dependencies.alacritty_config]
+path = "../alacritty_config"
+version = "0.1.0"
+
 [dependencies]
-clap = { version = "3.0.0", features = ["derive"] }
+clap = { version = "3.0.0", features = ["derive", "env"] }
 log = { version = "0.4", features = ["std", "serde"] }
 fnv = "1"
 serde = { version = "1", features = ["derive"] }
diff --git a/alacritty/src/cli.rs b/alacritty/src/cli.rs
index e9c563d4..e7aae207 100644
--- a/alacritty/src/cli.rs
+++ b/alacritty/src/cli.rs
@@ -81,14 +81,7 @@ impl Options {
         let mut options = Self::parse();
 
         // Convert `--option` flags into serde `Value`.
-        for option in &options.option {
-            match option_as_value(option) {
-                Ok(value) => {
-                    options.config_options = serde_utils::merge(options.config_options, value);
-                },
-                Err(_) => eprintln!("Invalid CLI config option: {:?}", option),
-            }
-        }
+        options.config_options = options_as_value(&options.option);
 
         options
     }
@@ -132,7 +125,18 @@ impl Options {
     }
 }
 
-/// Format an option in the format of `parent.field=value` to a serde Value.
+/// Combine multiple options into a [`serde_yaml::Value`].
+pub fn options_as_value(options: &[String]) -> Value {
+    options.iter().fold(Value::default(), |value, option| match option_as_value(option) {
+        Ok(new_value) => serde_utils::merge(value, new_value),
+        Err(_) => {
+            eprintln!("Ignoring invalid option: {:?}", option);
+            value
+        },
+    })
+}
+
+/// Parse an option in the format of `parent.field=value` as a serde Value.
 fn option_as_value(option: &str) -> Result<Value, serde_yaml::Error> {
     let mut yaml_text = String::with_capacity(option.len());
     let mut closing_brackets = String::new();
@@ -266,7 +270,7 @@ pub enum Subcommands {
 #[derive(Args, Debug)]
 pub struct MessageOptions {
     /// IPC socket connection path override.
-    #[clap(long, short, value_hint = ValueHint::FilePath)]
+    #[clap(short, long, value_hint = ValueHint::FilePath)]
     pub socket: Option<PathBuf>,
 
     /// Message which should be sent.
@@ -280,9 +284,12 @@ pub struct MessageOptions {
 pub enum SocketMessage {
     /// Create a new window in the same Alacritty process.
     CreateWindow(WindowOptions),
+
+    /// Update the Alacritty configuration.
+    Config(IpcConfig),
 }
 
-/// Subset of options that we pass to a 'create-window' subcommand.
+/// Subset of options that we pass to 'create-window' IPC subcommand.
 #[derive(Serialize, Deserialize, Args, Default, Clone, Debug, PartialEq, Eq)]
 pub struct WindowOptions {
     /// Terminal options which can be passed via IPC.
@@ -294,6 +301,25 @@ pub struct WindowOptions {
     pub window_identity: WindowIdentity,
 }
 
+/// Parameters to the `config` IPC subcommand.
+#[cfg(unix)]
+#[derive(Args, Serialize, Deserialize, Default, Debug, Clone, PartialEq, Eq)]
+pub struct IpcConfig {
+    /// Configuration file options [example: cursor.style=Beam].
+    #[clap(required = true, value_name = "CONFIG_OPTIONS")]
+    pub options: Vec<String>,
+
+    /// Window ID for the new config.
+    ///
+    /// Use `-1` to apply this change to all windows.
+    #[clap(short, long, allow_hyphen_values = true, env = "ALACRITTY_WINDOW_ID")]
+    pub window_id: Option<i128>,
+
+    /// Clear all runtime configuration changes.
+    #[clap(short, long, conflicts_with = "options")]
+    pub reset: bool,
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
diff --git a/alacritty/src/config/bindings.rs b/alacritty/src/config/bindings.rs
index c48b2d75..72ea88b2 100644
--- a/alacritty/src/config/bindings.rs
+++ b/alacritty/src/config/bindings.rs
@@ -9,7 +9,7 @@ use serde::de::{self, Error as SerdeError, MapAccess, Unexpected, Visitor};
 use serde::{Deserialize, Deserializer};
 use serde_yaml::Value as SerdeValue;
 
-use alacritty_config_derive::ConfigDeserialize;
+use alacritty_config_derive::{ConfigDeserialize, SerdeReplace};
 
 use alacritty_terminal::config::Program;
 use alacritty_terminal::term::TermMode;
@@ -1191,7 +1191,7 @@ impl<'a> Deserialize<'a> for KeyBinding {
 ///
 /// Our deserialize impl wouldn't be covered by a derive(Deserialize); see the
 /// impl below.
-#[derive(Debug, Copy, Clone, Hash, Default, Eq, PartialEq)]
+#[derive(SerdeReplace, Debug, Copy, Clone, Hash, Default, Eq, PartialEq)]
 pub struct ModsWrapper(pub ModifiersState);
 
 impl ModsWrapper {
diff --git a/alacritty/src/config/font.rs b/alacritty/src/config/font.rs
index d3431171..9c431b15 100644
--- a/alacritty/src/config/font.rs
+++ b/alacritty/src/config/font.rs
@@ -4,7 +4,7 @@ use crossfont::Size as FontSize;
 use serde::de::{self, Visitor};
 use serde::{Deserialize, Deserializer};
 
-use alacritty_config_derive::ConfigDeserialize;
+use alacritty_config_derive::{ConfigDeserialize, SerdeReplace};
 
 use crate::config::ui_config::Delta;
 
@@ -129,7 +129,7 @@ impl SecondaryFontDescription {
     }
 }
 
-#[derive(Debug, Clone, PartialEq, Eq)]
+#[derive(SerdeReplace, Debug, Clone, PartialEq, Eq)]
 struct Size(FontSize);
 
 impl Default for Size {
diff --git a/alacritty/src/config/ui_config.rs b/alacritty/src/config/ui_config.rs
index 28139d27..a332b737 100644
--- a/alacritty/src/config/ui_config.rs
+++ b/alacritty/src/config/ui_config.rs
@@ -9,7 +9,7 @@ use serde::de::{Error as SerdeError, MapAccess, Visitor};
 use serde::{self, Deserialize, Deserializer};
 use unicode_width::UnicodeWidthChar;
 
-use alacritty_config_derive::ConfigDeserialize;
+use alacritty_config_derive::{ConfigDeserialize, SerdeReplace};
 use alacritty_terminal::config::{
     Config as TerminalConfig, Percentage, Program, LOG_TARGET_CONFIG,
 };
@@ -30,7 +30,7 @@ use crate::config::window::WindowConfig;
 const URL_REGEX: &str = "(ipfs:|ipns:|magnet:|mailto:|gemini:|gopher:|https:|http:|news:|file:|git:|ssh:|ftp:)\
                          [^\u{0000}-\u{001F}\u{007F}-\u{009F}<>\"\\s{-}\\^⟨⟩`]+";
 
-#[derive(ConfigDeserialize, Debug, PartialEq)]
+#[derive(ConfigDeserialize, Clone, Debug, PartialEq)]
 pub struct UiConfig {
     /// Font configuration.
     pub font: Font,
@@ -145,7 +145,7 @@ impl UiConfig {
     }
 }
 
-#[derive(Debug, PartialEq, Eq)]
+#[derive(SerdeReplace, Clone, Debug, PartialEq, Eq)]
 struct KeyBindings(Vec<KeyBinding>);
 
 impl Default for KeyBindings {
@@ -163,7 +163,7 @@ impl<'de> Deserialize<'de> for KeyBindings {
     }
 }
 
-#[derive(Debug, PartialEq, Eq)]
+#[derive(SerdeReplace, Clone, Debug, PartialEq, Eq)]
 struct MouseBindings(Vec<MouseBinding>);
 
 impl Default for MouseBindings {
@@ -223,7 +223,7 @@ pub struct Delta<T: Default> {
 }
 
 /// Regex terminal hints.
-#[derive(ConfigDeserialize, Debug, PartialEq, Eq)]
+#[derive(ConfigDeserialize, Clone, Debug, PartialEq, Eq)]
 pub struct Hints {
     /// Characters for the hint labels.
     alphabet: HintsAlphabet,
@@ -273,7 +273,7 @@ impl Hints {
     }
 }
 
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(SerdeReplace, Clone, Debug, PartialEq, Eq)]
 struct HintsAlphabet(String);
 
 impl Default for HintsAlphabet {
diff --git a/alacritty/src/config/window.rs b/alacritty/src/config/window.rs
index 80df87b7..5d63d60f 100644
--- a/alacritty/src/config/window.rs
+++ b/alacritty/src/config/window.rs
@@ -6,7 +6,7 @@ use log::{error, warn};
 use serde::de::{self, MapAccess, Visitor};
 use serde::{Deserialize, Deserializer, Serialize};
 
-use alacritty_config_derive::ConfigDeserialize;
+use alacritty_config_derive::{ConfigDeserialize, SerdeReplace};
 use alacritty_terminal::config::{Percentage, LOG_TARGET_CONFIG};
 use alacritty_terminal::index::Column;
 
@@ -201,7 +201,7 @@ pub struct Dimensions {
 }
 
 /// Window class hint.
-#[derive(Serialize, Debug, Clone, PartialEq, Eq)]
+#[derive(SerdeReplace, Serialize, Debug, Clone, PartialEq, Eq)]
 pub struct Class {
     pub general: String,
     pub instance: String,
diff --git a/alacritty/src/display/window.rs b/alacritty/src/display/window.rs
index eac12a22..95b42345 100644
--- a/alacritty/src/display/window.rs
+++ b/alacritty/src/display/window.rs
@@ -405,16 +405,6 @@ impl Window {
         self.window().request_user_attention(attention);
     }
 
-    #[cfg(all(feature = "x11", not(any(target_os = "macos", windows))))]
-    pub fn x11_window_id(&self) -> Option<usize> {
-        self.window().xlib_window().map(|xlib_window| xlib_window as usize)
-    }
-
-    #[cfg(any(not(feature = "x11"), target_os = "macos", windows))]
-    pub fn x11_window_id(&self) -> Option<usize> {
-        None
-    }
-
     pub fn id(&self) -> WindowId {
         self.window().id()
     }
diff --git a/alacritty/src/event.rs b/alacritty/src/event.rs
index b4258a03..bd4b60b2 100644
--- a/alacritty/src/event.rs
+++ b/alacritty/src/event.rs
@@ -9,6 +9,7 @@ use std::fmt::Debug;
 #[cfg(not(windows))]
 use std::os::unix::io::RawFd;
 use std::path::PathBuf;
+use std::rc::Rc;
 use std::time::{Duration, Instant};
 use std::{env, f32, mem};
 
@@ -38,6 +39,8 @@ use alacritty_terminal::selection::{Selection, SelectionType};
 use alacritty_terminal::term::search::{Match, RegexSearch};
 use alacritty_terminal::term::{self, ClipboardType, Term, TermMode};
 
+#[cfg(unix)]
+use crate::cli::IpcConfig;
 use crate::cli::{Options as CliOptions, WindowOptions};
 use crate::clipboard::Clipboard;
 use crate::config::ui_config::{HintAction, HintInternalAction};
@@ -93,6 +96,8 @@ pub enum EventType {
     Message(Message),
     Scroll(Scroll),
     CreateWindow(WindowOptions),
+    #[cfg(unix)]
+    IpcConfig(IpcConfig),
     BlinkCursor,
     BlinkCursorTimeout,
     SearchNext,
@@ -184,7 +189,7 @@ pub struct ActionContext<'a, N, T> {
     pub modifiers: &'a mut ModifiersState,
     pub display: &'a mut Display,
     pub message_buffer: &'a mut MessageBuffer,
-    pub config: &'a mut UiConfig,
+    pub config: &'a UiConfig,
     pub cursor_blink_timed_out: &'a mut bool,
     pub event_loop: &'a EventLoopWindowTarget<Event>,
     pub event_proxy: &'a EventLoopProxy<Event>,
@@ -1162,6 +1167,8 @@ impl input::Processor<EventProxy, ActionContext<'_, Notifier, EventProxy>> {
                     TerminalEvent::Exit => (),
                     TerminalEvent::CursorBlinkingChange => self.ctx.update_cursor_blinking(),
                 },
+                #[cfg(unix)]
+                EventType::IpcConfig(_) => (),
                 EventType::ConfigReload(_) | EventType::CreateWindow(_) => (),
             },
             GlutinEvent::RedrawRequested(_) => *self.ctx.dirty = true,
@@ -1292,7 +1299,7 @@ pub struct Processor {
     wayland_event_queue: Option<EventQueue>,
     windows: HashMap<WindowId, WindowContext>,
     cli_options: CliOptions,
-    config: UiConfig,
+    config: Rc<UiConfig>,
 }
 
 impl Processor {
@@ -1313,8 +1320,8 @@ impl Processor {
 
         Processor {
             windows: HashMap::new(),
+            config: Rc::new(config),
             cli_options,
-            config,
             #[cfg(all(feature = "wayland", not(any(target_os = "macos", windows))))]
             wayland_event_queue,
         }
@@ -1328,7 +1335,7 @@ impl Processor {
         options: WindowOptions,
     ) -> Result<(), Box<dyn Error>> {
         let window_context = WindowContext::new(
-            &self.config,
+            self.config.clone(),
             &options,
             event_loop,
             proxy,
@@ -1436,7 +1443,6 @@ impl Processor {
                         window_context.handle_event(
                             event_loop,
                             &proxy,
-                            &mut self.config,
                             &mut clipboard,
                             &mut scheduler,
                             GlutinEvent::RedrawEventsCleared,
@@ -1457,13 +1463,27 @@ impl Processor {
 
                     // Load config and update each terminal.
                     if let Ok(config) = config::reload(&path, &self.cli_options) {
-                        let old_config = mem::replace(&mut self.config, config);
+                        self.config = Rc::new(config);
 
                         for window_context in self.windows.values_mut() {
-                            window_context.update_config(&old_config, &self.config);
+                            window_context.update_config(self.config.clone());
                         }
                     }
                 },
+                // Process IPC config update.
+                #[cfg(unix)]
+                GlutinEvent::UserEvent(Event {
+                    payload: EventType::IpcConfig(ipc_config),
+                    window_id,
+                }) => {
+                    for (_, window_context) in self
+                        .windows
+                        .iter_mut()
+                        .filter(|(id, _)| window_id.is_none() || window_id == Some(**id))
+                    {
+                        window_context.update_ipc_config(self.config.clone(), ipc_config.clone());
+                    }
+                },
                 // Create a new terminal window.
                 GlutinEvent::UserEvent(Event {
                     payload: EventType::CreateWindow(options), ..
@@ -1485,7 +1505,6 @@ impl Processor {
                         window_context.handle_event(
                             event_loop,
                             &proxy,
-                            &mut self.config,
                             &mut clipboard,
                             &mut scheduler,
                             event.clone().into(),
@@ -1500,7 +1519,6 @@ impl Processor {
                         window_context.handle_event(
                             event_loop,
                             &proxy,
-                            &mut self.config,
                             &mut clipboard,
                             &mut scheduler,
                             event,
diff --git a/alacritty/src/ipc.rs b/alacritty/src/ipc.rs
index d4c807ba..e229a048 100644
--- a/alacritty/src/ipc.rs
+++ b/alacritty/src/ipc.rs
@@ -7,6 +7,7 @@ use std::path::PathBuf;
 use std::{env, fs, process};
 
 use glutin::event_loop::EventLoopProxy;
+use glutin::window::WindowId;
 use log::warn;
 
 use alacritty_terminal::thread;
@@ -62,6 +63,14 @@ pub fn spawn_ipc_socket(options: &Options, event_proxy: EventLoopProxy<Event>) -
                     let event = Event::new(EventType::CreateWindow(options), None);
                     let _ = event_proxy.send_event(event);
                 },
+                SocketMessage::Config(ipc_config) => {
+                    let window_id = ipc_config
+                        .window_id
+                        .and_then(|id| u64::try_from(id).ok())
+                        .map(WindowId::from);
+                    let event = Event::new(EventType::IpcConfig(ipc_config), window_id);
+                    let _ = event_proxy.send_event(event);
+                },
             }
         }
     });
diff --git a/alacritty/src/window_context.rs b/alacritty/src/window_context.rs
index e75f118d..9a2a8730 100644
--- a/alacritty/src/window_context.rs
+++ b/alacritty/src/window_context.rs
@@ -6,6 +6,7 @@ use std::io::Write;
 use std::mem;
 #[cfg(not(windows))]
 use std::os::unix::io::{AsRawFd, RawFd};
+use std::rc::Rc;
 #[cfg(not(any(target_os = "macos", windows)))]
 use std::sync::atomic::Ordering;
 use std::sync::Arc;
@@ -14,11 +15,12 @@ use crossfont::Size;
 use glutin::event::{Event as GlutinEvent, ModifiersState, WindowEvent};
 use glutin::event_loop::{EventLoopProxy, EventLoopWindowTarget};
 use glutin::window::WindowId;
-use log::info;
+use log::{error, info};
 use serde_json as json;
 #[cfg(all(feature = "wayland", not(any(target_os = "macos", windows))))]
 use wayland_client::EventQueue;
 
+use alacritty_config::SerdeReplace;
 use alacritty_terminal::event::Event as TerminalEvent;
 use alacritty_terminal::event_loop::{EventLoop as PtyEventLoop, Msg, Notifier};
 use alacritty_terminal::grid::{Dimensions, Scroll};
@@ -28,6 +30,8 @@ use alacritty_terminal::term::test::TermSize;
 use alacritty_terminal::term::{Term, TermMode};
 use alacritty_terminal::tty;
 
+#[cfg(unix)]
+use crate::cli::IpcConfig;
 use crate::cli::WindowOptions;
 use crate::clipboard::Clipboard;
 use crate::config::UiConfig;
@@ -58,12 +62,14 @@ pub struct WindowContext {
     master_fd: RawFd,
     #[cfg(not(windows))]
     shell_pid: u32,
+    ipc_config: Vec<(String, serde_yaml::Value)>,
+    config: Rc<UiConfig>,
 }
 
 impl WindowContext {
     /// Create a new terminal window context.
     pub fn new(
-        config: &UiConfig,
+        config: Rc<UiConfig>,
         options: &WindowOptions,
         window_event_loop: &EventLoopWindowTarget<Event>,
         proxy: EventLoopProxy<Event>,
@@ -81,7 +87,7 @@ impl WindowContext {
         //
         // The display manages a window and can draw the terminal.
         let display = Display::new(
-            config,
+            &config,
             window_event_loop,
             &identity,
             #[cfg(all(feature = "wayland", not(any(target_os = "macos", windows))))]
@@ -109,7 +115,7 @@ impl WindowContext {
         // The PTY forks a process to run the shell on the slave side of the
         // pseudoterminal. A file descriptor for the master side is retained for
         // reading/writing to the shell.
-        let pty = tty::new(&pty_config, display.size_info.into(), display.window.x11_window_id())?;
+        let pty = tty::new(&pty_config, display.size_info.into(), display.window.id().into())?;
 
         #[cfg(not(windows))]
         let master_fd = pty.file().as_raw_fd();
@@ -142,23 +148,27 @@ impl WindowContext {
             event_proxy.send_event(TerminalEvent::CursorBlinkingChange.into());
         }
 
+        let font_size = config.font.size();
+
         // Create context for the Alacritty window.
         Ok(WindowContext {
-            font_size: config.font.size(),
-            notifier: Notifier(loop_tx),
+            preserve_title,
+            font_size,
             terminal,
             display,
-            preserve_title,
             #[cfg(not(windows))]
             master_fd,
             #[cfg(not(windows))]
             shell_pid,
+            config,
+            notifier: Notifier(loop_tx),
             cursor_blink_timed_out: Default::default(),
             suppress_chars: Default::default(),
             message_buffer: Default::default(),
             received_count: Default::default(),
             search_state: Default::default(),
             event_queue: Default::default(),
+            ipc_config: Default::default(),
             modifiers: Default::default(),
             mouse: Default::default(),
             dirty: Default::default(),
@@ -167,33 +177,49 @@ impl WindowContext {
     }
 
     /// Update the terminal window to the latest config.
-    pub fn update_config(&mut self, old_config: &UiConfig, config: &UiConfig) {
-        self.display.update_config(config);
-        self.terminal.lock().update_config(&config.terminal_config);
+    pub fn update_config(&mut self, new_config: Rc<UiConfig>) {
+        let old_config = mem::replace(&mut self.config, new_config);
+
+        // Apply ipc config if there are overrides.
+        if !self.ipc_config.is_empty() {
+            let mut config = (*self.config).clone();
+
+            // Apply each option.
+            for (key, value) in &self.ipc_config {
+                if let Err(err) = config.replace(key, value.clone()) {
+                    error!("Unable to override option '{}': {}", key, err);
+                }
+            }
+
+            self.config = Rc::new(config);
+        }
+
+        self.display.update_config(&self.config);
+        self.terminal.lock().update_config(&self.config.terminal_config);
 
         // Reload cursor if its thickness has changed.
         if (old_config.terminal_config.cursor.thickness()
-            - config.terminal_config.cursor.thickness())
+            - self.config.terminal_config.cursor.thickness())
         .abs()
             > f32::EPSILON
         {
             self.display.pending_update.set_cursor_dirty();
         }
 
-        if old_config.font != config.font {
+        if old_config.font != self.config.font {
             // Do not update font size if it has been changed at runtime.
             if self.font_size == old_config.font.size() {
-                self.font_size = config.font.size();
+                self.font_size = self.config.font.size();
             }
 
-            let font = config.font.clone().with_size(self.font_size);
+            let font = self.config.font.clone().with_size(self.font_size);
             self.display.pending_update.set_font(font);
         }
 
         // Update display if padding options were changed.
         let window_config = &old_config.window;
-        if window_config.padding(1.) != config.window.padding(1.)
-            || window_config.dynamic_padding != config.window.dynamic_padding
+        if window_config.padding(1.) != self.config.window.padding(1.)
+            || window_config.dynamic_padding != self.config.window.dynamic_padding
         {
             self.display.pending_update.dirty = true;
         }
@@ -206,18 +232,18 @@ impl WindowContext {
         // │ N  │       Y       │              N              ││     N     │
         // │ N  │       N       │              _              ││     Y     │
         if !self.preserve_title
-            && (!config.window.dynamic_title
+            && (!self.config.window.dynamic_title
                 || self.display.window.title() == old_config.window.identity.title)
         {
-            self.display.window.set_title(config.window.identity.title.clone());
+            self.display.window.set_title(self.config.window.identity.title.clone());
         }
 
         // Disable shadows for transparent windows on macOS.
         #[cfg(target_os = "macos")]
-        self.display.window.set_has_shadow(config.window_opacity() >= 1.0);
+        self.display.window.set_has_shadow(self.config.window_opacity() >= 1.0);
 
         // Update hint keys.
-        self.display.hint_state.update_alphabet(config.hints.alphabet());
+        self.display.hint_state.update_alphabet(self.config.hints.alphabet());
 
         // Update cursor blinking.
         let event = Event::new(TerminalEvent::CursorBlinkingChange.into(), None);
@@ -226,12 +252,39 @@ impl WindowContext {
         self.dirty = true;
     }
 
+    /// Update the IPC config overrides.
+    #[cfg(unix)]
+    pub fn update_ipc_config(&mut self, config: Rc<UiConfig>, ipc_config: IpcConfig) {
+        self.ipc_config.clear();
+
+        if !ipc_config.reset {
+            for option in &ipc_config.options {
+                // Separate config key/value.
+                let (key, value) = match option.split_once('=') {
+                    Some(split) => split,
+                    None => {
+                        error!("'{}': IPC config option missing value", option);
+                        continue;
+                    },
+                };
+