chansrv: Reconnect ibus when the cached connection has gone stale

Fixes #3230. The static `bus` global was only ever checked for
non-NULL, not for whether the underlying connection was still alive.
If ibus disconnected (daemon restart, stale socket) or the initial
connect attempt failed, `bus` was left set to a dead/freed connection,
so every later call to xrdp_input_unicode_init() took the "already
initialized" fast path and operated on it.

- Null out bus/g_engine in the "disconnected" signal handler instead
  of leaving them dangling after g_object_unref().
- Check ibus_bus_is_connected() before trusting a cached bus, and
  tear down + reconnect if it's stale.
- Unref and clear bus on a failed connect attempt instead of leaving
  it set.
- Guard the unrefs in xrdp_input_unicode_destroy() now that bus/
  g_engine can legitimately already be NULL.

.devcontainer/Dockerfile

@@ -0,0 +1,100 @@
+FROM ubuntu:24.04 AS builder
+
+# Pilot build against the xrdp/xorgxrdp "devel" branches (pre-0.11).
+# This is NOT the same codebase as Dockerfile (v0.10.x) - devel is ~787
+# commits / ~300 files ahead of v0.10.6.1, and xorgxrdp's devel branch has
+# moved together with it (137 commits / 81 files ahead of v0.10.5). Track
+# them as a pair; don't mix a devel xrdp with a tagged xorgxrdp or vice versa.
+#
+# Known deltas from the v0.10.x build baked into this file:
+#   - New hard dep: libxkbfile-dev (unconditional XKB header check)
+#   - --enable-ibus now also needs libibus-1.0-dev + libglib2.0-dev
+#   - NVENC support moved into a new helper binary (xrdp-accel-assist) that
+#     vendors its own NVENC API headers, so the nv-codec-headers clone/symlink
+#     step from the stable Dockerfile is gone - it's dead weight on devel.
+#   - --enable-accel is auto-derived from --enable-nvenc in configure.ac, so
+#     no new configure flag is needed to get xrdp-accel-assist built.
+#
+# devel is a floating branch, not a tag: Docker layer caching means a
+# `docker build` with no cache change will keep reusing an old clone.
+# Always pass --no-cache (or otherwise bust the git-clone layers) to actually
+# pick up new commits on each pilot run.
+#
+# Usage:
+#   docker build --no-cache -f Dockerfile.devel -t xrdp-builder:devel .
+#   docker run --rm -v $(pwd)/packages:/output xrdp-builder:devel
+
+# Get build and target platform info
+ARG TARGETPLATFORM
+ARG BUILDPLATFORM
+ARG TARGETARCH
+ARG TARGETVARIANT
+
+# Build arguments for versions - devel branches by default for this pilot
+ARG XRDP_VERSION=devel
+ARG XORGXRDP_VERSION=devel
+ARG PW_MODULE_XRDP_VERSION=devel
+
+# Prevent interactive prompts during build
+ENV DEBIAN_FRONTEND=noninteractive
+
+# Install build dependencies
+RUN apt-get update && apt-get install -y \
+    git \
+    autoconf \
+    automake \
+    libtool \
+    pkg-config \
+    gcc \
+    g++ \
+    make \
+    libssl-dev \
+    libpam0g-dev \
+    libx11-dev \
+    libxfixes-dev \
+    libxrandr-dev \
+    libxkbfile-dev \
+    nasm \
+    xsltproc \
+    flex \
+    bison \
+    libxml2-dev \
+    dpkg-dev \
+    libcap-dev \
+    libfuse3-dev \
+    libpixman-1-dev \
+    intltool \
+    xserver-xorg-dev \
+    xserver-xorg-core \
+    libconfig-dev \
+    libjpeg-dev \
+    wget \
+    libturbojpeg-dev \
+    libx264-dev \
+    libpulse-dev \
+    libopus-dev \
+    libibus-1.0-dev \
+    libglib2.0-dev \
+    ca-certificates \
+    libepoxy-dev \
+    libasound2-dev \
+    libdrm-dev \
+    libglvnd-dev \
+    libgbm-dev \
+    pipewire \
+    libpipewire-0.3-dev \
+    libspa-0.2-dev \
+    && rm -rf /var/lib/apt/lists/*
+
+RUN apt-get update && apt-get install -y \
+    nano \
+    xvfb \
+    xdotool \
+    ibus \
+    dbus-x11 \
+    openbox \
+    && rm -rf /var/lib/apt/lists/*
+
+# Match the workspaceFolder set in devcontainer.json
+WORKDIR /workspace
+CMD [ "tail", "-f", "/dev/null" ]

.devcontainer/devcontainer.json

@@ -0,0 +1,29 @@
+{
+  "$schema": "https://raw.githubusercontent.com/devcontainers/spec/main/schemas/devContainer.schema.json",
+  "name": "XRDP",
+  "build": { "dockerfile": "Dockerfile" },
+  "workspaceFolder": "/workspace",
+  "workspaceMount": "source=${localWorkspaceFolder},target=/workspace,type=bind",
+  "remoteUser": "root",
+  "mounts": [
+  {
+    "source": "${localEnv:HOME}${localEnv:USERPROFILE}/.claude",
+    "target": "/root/.claude",
+    "type": "bind",
+    "consistency": "cached"
+  },
+  {
+    "source": "${localEnv:HOME}${localEnv:USERPROFILE}/.gitconfig",
+    "target": "/root/.gitconfig",
+    "type": "bind",
+    "consistency": "cached"
+  },
+  {
+    "source": "${localEnv:HOME}${localEnv:USERPROFILE}/.git-credentials",
+    "target": "/root/.git-credentials",
+    "type": "bind",
+    "consistency": "cached"
+  }
+
+]
+}

sesman/chansrv/input_ibus.c

@@ -30,7 +30,7 @@
 static IBusBus *bus;
 static IBusEngine *g_engine;
 /* This is the engine name enabled before unicode engine enabled */
-static const gchar *last_input_name;
+static gchar *last_input_name;
 static int id = 0;
 
 static int
@@ -39,27 +39,38 @@ xrdp_input_enable(void)
     IBusEngineDesc *desc;
     const gchar *name;
 
-    if (last_input_name)
-    {
-        /* already enabled */
-        return 0;
-    }
-
     if (!bus)
     {
         LOG(LOG_LEVEL_ERROR, "xrdp_ibus_init: input method switched failed, ibus not connected");
         return 1;
     }
 
+    /* Re-check the current global engine on every call rather than
+     * trusting a one-time flag: ibus (particularly with
+     * use_global_engine disabled, which is common) can silently swap
+     * the active engine back to the user's own IME between calls, and
+     * we need to notice that and reassert XrdpIme rather than keep
+     * committing text to an engine that's no longer active. */
     desc = ibus_bus_get_global_engine(bus);
-    name = ibus_engine_desc_get_name (desc);
-    if (!g_ascii_strcasecmp(name, "XrdpIme"))
+    name = desc ? ibus_engine_desc_get_name(desc) : NULL;
+    if (name && !g_ascii_strcasecmp(name, "XrdpIme"))
     {
+        g_object_unref(desc);
         return 0;
     }
 
-    /* remember user's input method, will switch back when disconnect */
-    last_input_name = name;
+    if (!last_input_name && name)
+    {
+        /* remember user's original input method (first time only), will
+         * switch back when disconnected. Copy the name out since it's
+         * owned by desc, which we're about to unref. */
+        last_input_name = g_strdup(name);
+    }
+
+    if (desc)
+    {
+        g_object_unref(desc);
+    }
 
     if (!ibus_bus_set_global_engine(bus, "XrdpIme"))
     {
@@ -105,8 +116,25 @@ static void
 xrdp_input_ibus_disconnect(IBusEngine *engine)
 {
     LOG(LOG_LEVEL_INFO, "xrdp_ibus_engine_disable: IM disabled");
-    g_object_unref(g_engine);
-    g_object_unref(bus);
+    if (g_engine)
+    {
+        g_object_unref(g_engine);
+        g_engine = NULL;
+    }
+    if (bus)
+    {
+        g_object_unref(bus);
+        bus = NULL;
+    }
+    g_free(last_input_name);
+    last_input_name = NULL;
+
+    /* ibus_main()/ibus_quit() operate on a single loop shared by the
+     * whole process, not one per IBusBus. Without this, the
+     * xrdp_input_main_loop thread for this (now dead) connection stays
+     * blocked in ibus_main() forever, and a fresh thread + loop gets
+     * started on the next reconnect - leaking a thread per reconnect. */
+    ibus_quit();
 }
 
 static gboolean
@@ -125,12 +153,13 @@ xrdp_input_ibus_create_engine(IBusFactory *factory,
                               gpointer user_data)
 {
     IBusEngine *engine;
-    gchar *path = g_strdup_printf("/org/freedesktop/IBus/Engine/%i", 1);
+    gchar *path = g_strdup_printf("/org/freedesktop/IBus/Engine/%i", ++id);
     engine = ibus_engine_new(engine_name,
                              path,
                              ibus_bus_get_connection(bus));
 
-    LOG(LOG_LEVEL_DEBUG, "xrdp_input_ibus_create_engine: Creating IM Engine with name:%s and id:%d\n", engine_name, ++id);
+    LOG(LOG_LEVEL_DEBUG, "xrdp_input_ibus_create_engine: Creating IM Engine with name:%s and id:%d\n", engine_name, id);
+    g_free(path);
 
     g_signal_connect(engine, "process-key-event", G_CALLBACK(engine_process_key_event_cb), NULL);
     g_signal_connect(engine, "enable", G_CALLBACK(xrdp_input_ibus_engine_enable), NULL);
@@ -192,15 +221,22 @@ int
 xrdp_input_unicode_destroy(void)
 {
     LOG(LOG_LEVEL_DEBUG, "xrdp_input_unicode_destory: ibus input is under destory");
-    if (last_input_name)
+    if (last_input_name && bus)
     {
         LOG(LOG_LEVEL_INFO, "xrdp_input_unicode_destory: ibus engine rolling back to origin: %s", last_input_name);
         ibus_bus_set_global_engine(bus, last_input_name);
     }
 
-    g_object_unref(g_engine);
-    g_object_unref(bus);
+    if (g_engine)
+    {
+        g_object_unref(g_engine);
+    }
+    if (bus)
+    {
+        g_object_unref(bus);
+    }
 
+    g_free(last_input_name);
     last_input_name = NULL;
     bus = NULL;
     g_engine = NULL;
@@ -213,9 +249,36 @@ xrdp_input_unicode_init(void)
 {
     if (bus)
     {
-        /* Already initialized, just re-enable it */
-        xrdp_input_enable();
-        return 0;
+        if (ibus_bus_is_connected(bus))
+        {
+            /* Already initialized, just re-enable it */
+            xrdp_input_enable();
+            return 0;
+        }
+
+        /* The bus is stale (e.g. the ibus daemon restarted and left a
+         * dead connection behind). Tear it down so we reconnect below
+         * instead of operating on a dead connection. */
+        LOG(LOG_LEVEL_WARNING,
+            "xrdp_ibus_init: existing iBus connection is stale, reconnecting");
+        if (g_engine)
+        {
+            g_object_unref(g_engine);
+            g_engine = NULL;
+        }
+        g_object_unref(bus);
+        bus = NULL;
+        g_free(last_input_name);
+        last_input_name = NULL;
+
+        /* Belt-and-suspenders: normally the "disconnected" signal handler
+         * (xrdp_input_ibus_disconnect) already called this when the bus
+         * dropped. But a stale connection can be detected here without
+         * that signal ever having fired, and ibus_main()/ibus_quit() are
+         * process-global rather than per-bus, so make sure the old
+         * xrdp_input_main_loop thread isn't left blocked in ibus_main()
+         * before we start a new one below. */
+        ibus_quit();
     }
 
     /* Wait because the ibus daemon may not be ready on first login */
@@ -242,6 +305,8 @@ xrdp_input_unicode_init(void)
     if (!ibus_bus_is_connected(bus))
     {
         LOG(LOG_LEVEL_ERROR, "xrdp_ibus_init: Connect to iBus failed");
+        g_object_unref(bus);
+        bus = NULL;
         return 1;
     }
 
@@ -251,6 +316,9 @@ xrdp_input_unicode_init(void)
 
     if (!ibus_bus_get_global_engine(bus))
     {
+        /* The bus connection itself is fine (and is now owned by the
+         * ibus main loop thread we just started), so leave it in place
+         * rather than tearing it down here. */
         LOG(LOG_LEVEL_ERROR, "xrdp_ibus_init: failed to get origin global engine");
         return 1;
     }