change name of config entry and variables, add lock for safety during config update

docs/sequences/enq.md

@@ -10,8 +10,8 @@ operator.
 
 ## Implementation Details
 
-The answerback can be configured in the config file using the `enquiry-string`
+The answerback can be configured in the config file using the `enquiry-response`
-configuration setting or on the command line using the `--enquiry-string`
+configuration setting or on the command line using the `--enquiry-response`
 parameter. The default is to send an empty string (`""`).
 
 ## References

src/config/Config.zig

@@ -898,7 +898,7 @@ term: []const u8 = "xterm-ghostty",
 
 /// String to send when we receive ENQ (0x05) from the command that we are
 /// running. Defaults to "" if not set.
-@"enquiry-string": ?[]const u8 = null,
+@"enquiry-response": ?[]const u8 = null,
 
 /// This is set by the CLI parser for deinit.
 _arena: ?ArenaAllocator = null,

src/termio/Exec.zig

@@ -51,7 +51,7 @@ abnormal_runtime_threshold_ms: u32,
 
 /// Equiry string - the string to send back when we receive a ENQ (0x05)
 /// from the process.
-enquiry_string: ?[]const u8 = null,
+enquiry_response: ?[]const u8 = null,
 
 /// The terminal emulator internal state. This is the abstract "terminal"
 /// that manages input, grid updating, etc. and is renderer-agnostic. It
@@ -116,7 +116,7 @@ pub const DerivedConfig = struct {
     term: []const u8,
     grapheme_width_method: configpkg.Config.GraphemeWidthMethod,
     abnormal_runtime_threshold_ms: u32,
-    enquiry_string: ?[]const u8,
+    enquiry_response: ?[]const u8,
 
     pub fn init(
         alloc_gpa: Allocator,
@@ -136,7 +136,7 @@ pub const DerivedConfig = struct {
             .term = config.term,
             .grapheme_width_method = config.@"grapheme-width-method",
             .abnormal_runtime_threshold_ms = config.@"abnormal-command-exit-runtime",
-            .enquiry_string = config.@"enquiry-string",
+            .enquiry_response = config.@"enquiry-response",
         };
     }
 
@@ -216,7 +216,7 @@ pub fn init(alloc: Allocator, opts: termio.Options) !Exec {
         .osc_color_report_format = config.osc_color_report_format,
         .data = null,
         .abnormal_runtime_threshold_ms = opts.config.abnormal_runtime_threshold_ms,
-        .enquiry_string = if (opts.config.enquiry_string) |s| try alloc.dupe(u8, s) else null,
+        .enquiry_response = if (opts.config.enquiry_response) |s| try alloc.dupe(u8, s) else null,
     };
 }
 
@@ -226,7 +226,7 @@ pub fn deinit(self: *Exec) void {
     // Clean up our other members
     self.terminal.deinit(self.alloc);
 
-    if (self.enquiry_string) |s| self.alloc.free(s);
+    if (self.enquiry_response) |s| self.alloc.free(s);
 }
 
 pub fn threadEnter(self: *Exec, thread: *termio.Thread) !ThreadData {
@@ -306,7 +306,8 @@ pub fn threadEnter(self: *Exec, thread: *termio.Thread) !ThreadData {
                 .foreground_color = self.foreground_color,
                 .background_color = self.background_color,
                 .osc_color_report_format = self.osc_color_report_format,
-                .enquiry_string = if (self.enquiry_string) |s| try self.alloc.dupe(u8, s) else null,
+                .enquiry_response = if (self.enquiry_response) |s| try self.alloc.dupe(u8, s) else null,
+                .enquiry_response_lock = .{},
             },
 
             .parser = .{
@@ -441,8 +442,12 @@ pub fn changeConfig(self: *Exec, config: *DerivedConfig) !void {
             config.cursor_style,
             config.cursor_blink,
         );
-        if (data.terminal_stream.handler.enquiry_string) |s| data.terminal_stream.handler.alloc.free(s);
+        {
-        data.terminal_stream.handler.enquiry_string = if (config.enquiry_string) |s| try data.terminal_stream.handler.alloc.dupe(u8, s) else null;
+            data.terminal_stream.handler.enquiry_response_lock.lock();
+            defer data.terminal_stream.handler.enquiry_response_lock.unlock();
+            if (data.terminal_stream.handler.enquiry_response) |s| data.terminal_stream.handler.alloc.free(s);
+            data.terminal_stream.handler.enquiry_response = if (config.enquiry_response) |s| try data.terminal_stream.handler.alloc.dupe(u8, s) else null;
+        }
     }
 
     // Set the image size limits
@@ -1707,12 +1712,13 @@ const StreamHandler = struct {
 
     osc_color_report_format: configpkg.Config.OSCColorReportFormat,
 
-    enquiry_string: ?[]const u8 = null,
+    enquiry_response: ?[]const u8,
+    enquiry_response_lock: std.Thread.RwLock,
 
     pub fn deinit(self: *StreamHandler) void {
         self.apc.deinit();
         self.dcs.deinit();
-        if (self.enquiry_string) |s| self.alloc.free(s);
+        if (self.enquiry_response) |s| self.alloc.free(s);
     }
 
     inline fn queueRender(self: *StreamHandler) !void {
@@ -2405,8 +2411,14 @@ const StreamHandler = struct {
     }
 
     pub fn enquiry(self: *StreamHandler) !void {
-        log.debug("sending equiry string '{any}''", .{self.enquiry_string orelse ""});
+        self.enquiry_response_lock.lockShared();
-        self.messageWriter(.{ .write_stable = self.enquiry_string orelse "" });
+        defer self.enquiry_response_lock.unlock();
+        log.debug("sending enquiry response={any}", .{self.enquiry_response orelse ""});
+        if (self.enquiry_response) |r| {
+            self.messageWriter(try termio.Message.writeReq(self.alloc, r));
+        } else {
+            self.messageWriter(.{ .write_stable = "" });
+        }
     }
 
     pub fn scrollDown(self: *StreamHandler, count: usize) !void {