From 11735290b848a30c4b47e26fd2e95f23da623d5e Mon Sep 17 00:00:00 2001
From: AnErrupTion <anerruption@disroot.org>
Date: Thu, 5 Feb 2026 19:50:48 +0100
Subject: [PATCH] Fix active TTY detection for KMSCON

Signed-off-by: AnErrupTion <anerruption@disroot.org>
---
 ly-core/src/interop.zig | 21 +++++++++++++++++----
 src/main.zig            |  4 ++--
 2 files changed, 19 insertions(+), 6 deletions(-)

diff --git a/ly-core/src/interop.zig b/ly-core/src/interop.zig
index 1ba8613..ef542f7 100644
--- a/ly-core/src/interop.zig
+++ b/ly-core/src/interop.zig
@@ -96,8 +96,21 @@ fn PlatformStruct() type {
             // 4. Finally, compare the major and minor device numbers with the
             //    extracted values. If they correspond, parse [dir] to get the
             //    TTY ID
-            pub fn getActiveTtyImpl(allocator: std.mem.Allocator) !u8 {
+            pub fn getActiveTtyImpl(allocator: std.mem.Allocator, use_kmscon_vt: bool) !u8 {
                 var file_buffer: [256]u8 = undefined;
+
+                if (use_kmscon_vt) {
+                    var file = try std.fs.openFileAbsolute("/sys/class/tty/tty0/active", .{});
+                    defer file.close();
+
+                    var reader = file.reader(&file_buffer);
+                    var buffer: [16]u8 = undefined;
+                    const read = try readBuffer(&reader.interface, &buffer);
+
+                    const tty = buffer[0..(read - 1)];
+                    return std.fmt.parseInt(u8, tty["tty".len..], 10);
+                }
+
                 var tty_major: u16 = undefined;
                 var tty_minor: u16 = undefined;
 
@@ -242,7 +255,7 @@ fn PlatformStruct() type {
                 if (result != 0) return error.SetUserUidFailed;
             }
 
-            pub fn getActiveTtyImpl(_: std.mem.Allocator) !u8 {
+            pub fn getActiveTtyImpl(_: std.mem.Allocator, _: bool) !u8 {
                 return error.FeatureUnimplemented;
             }
 
@@ -285,8 +298,8 @@ pub fn getTimeOfDay() !TimeOfDay {
     };
 }
 
-pub fn getActiveTty(allocator: std.mem.Allocator) !u8 {
-    return platform_struct.getActiveTtyImpl(allocator);
+pub fn getActiveTty(allocator: std.mem.Allocator, use_kmscon_vt: bool) !u8 {
+    return platform_struct.getActiveTtyImpl(allocator, use_kmscon_vt);
 }
 
 pub fn switchTty(tty: u8) !void {
diff --git a/src/main.zig b/src/main.zig
index f2e2fcd..cc305c4 100644
--- a/src/main.zig
+++ b/src/main.zig
@@ -568,14 +568,14 @@ pub fn main() !void {
     var inactivity_cmd_ran = false;
 
     // Switch to selected TTY
-    const active_tty = interop.getActiveTty(allocator) catch |err| no_tty_found: {
+    const active_tty = interop.getActiveTty(allocator, use_kmscon_vt) catch |err| no_tty_found: {
         try info_line.addMessage(lang.err_get_active_tty, config.error_bg, config.error_fg);
         try log_file.err("sys", "failed to get active tty: {s}", .{@errorName(err)});
         break :no_tty_found build_options.fallback_tty;
     };
     interop.switchTty(active_tty) catch |err| {
         try info_line.addMessage(lang.err_switch_tty, config.error_bg, config.error_fg);
-        try log_file.err("sys", "failed to switch tty: {s}", .{@errorName(err)});
+        try log_file.err("sys", "failed to switch to tty {d}: {s}", .{ active_tty, @errorName(err) });
     };
 
     if (config.initial_info_text) |text| {