From aecb5a71c0461c767c26bb1a14da30bdfd8313af Mon Sep 17 00:00:00 2001
From: April & May <apr3vau@outlook.com>
Date: Thu, 28 Aug 2025 11:13:19 +0800
Subject: [PATCH] fix: refine TTY switching

1. Add callback for disableRender, to ensure render is exactly disabled
before DDM doing further actions;
2. Revoke all evdev devices before VT switch (at disableRender()), to
prevent accidental input events during switch;
3. Refine logic of switchToUser, take care of showing lockscreen after
switch;
4. Make event function args const
---
 src/modules/ddm/ddminterfacev1.cpp | 19 ++++++++++++++-----
 src/modules/ddm/ddminterfacev1.h   |  4 ++--
 src/seat/helper.cpp                | 16 ++++++++++++++++
 3 files changed, 32 insertions(+), 7 deletions(-)

diff --git a/src/modules/ddm/ddminterfacev1.cpp b/src/modules/ddm/ddminterfacev1.cpp
index e8c07b1acd..5d96581926 100644
--- a/src/modules/ddm/ddminterfacev1.cpp
+++ b/src/modules/ddm/ddminterfacev1.cpp
@@ -23,8 +23,13 @@ static void switchToGreeter([[maybe_unused]] struct wl_client *client, [[maybe_u
 }
 
 static void switchToUser([[maybe_unused]] struct wl_client *client, [[maybe_unused]] struct wl_resource *resource, const char *username) {
-    if (strcmp(username, "ddm") != 0) {
-        Helper::instance()->userModel()->setCurrentUserName(QString(username));
+    auto user = QString::fromLocal8Bit(username);
+    auto helper = Helper::instance();
+    if (user == "ddm") {
+        helper->showLockScreen(false);
+    } else if (user != helper->userModel()->currentUserName()) {
+        helper->userModel()->setCurrentUserName(QString(username));
+        helper->showLockScreen(false);
     }
 }
 
@@ -40,8 +45,12 @@ static void enableRender([[maybe_unused]] struct wl_client *client, [[maybe_unus
     Helper::instance()->enableRender();
 }
 
-static void disableRender([[maybe_unused]] struct wl_client *client, [[maybe_unused]] struct wl_resource *resource) {
+static void disableRender(struct wl_client *client, [[maybe_unused]] struct wl_resource *resource, uint32_t id) {
     Helper::instance()->disableRender();
+    auto callback = wl_resource_create(client, &wl_callback_interface, 1, id);
+    auto serial = wl_display_get_serial(wl_client_get_display(client));
+    wl_callback_send_done(callback, serial);
+    wl_resource_destroy(callback);
 }
 
 static const struct treeland_ddm_interface treeland_ddm_impl {
@@ -110,7 +119,7 @@ wl_global *DDMInterfaceV1::global() const {
 
 // Event wrapper
 
-void DDMInterfaceV1::switchToVt(int vtnr) {
+void DDMInterfaceV1::switchToVt(const int vtnr) {
     auto ddm = static_cast<struct treeland_ddm *>(m_handle);
     if (isConnected())
         treeland_ddm_send_switch_to_vt(ddm->resource, vtnr);
@@ -118,7 +127,7 @@ void DDMInterfaceV1::switchToVt(int vtnr) {
         qCWarning(treelandCore) << "DDM is not conected when trying to call switchToVt";
 }
 
-void DDMInterfaceV1::acquireVt(int vtnr) {
+void DDMInterfaceV1::acquireVt(const int vtnr) {
     auto ddm = static_cast<struct treeland_ddm *>(m_handle);
     if (isConnected())
         treeland_ddm_send_acquire_vt(ddm->resource, vtnr);
diff --git a/src/modules/ddm/ddminterfacev1.h b/src/modules/ddm/ddminterfacev1.h
index 2eae63b57d..5bd796911b 100644
--- a/src/modules/ddm/ddminterfacev1.h
+++ b/src/modules/ddm/ddminterfacev1.h
@@ -12,8 +12,8 @@ class DDMInterfaceV1 : public Waylib::Server::WServerInterface {
     ~DDMInterfaceV1() override;
     QByteArrayView interfaceName() const override;
     bool isConnected() const;
-    void switchToVt(int vtnr);
-    void acquireVt(int vtnr);
+    void switchToVt(const int vtnr);
+    void acquireVt(const int vtnr);
 protected:
     void create(Waylib::Server::WServer *server) override;
     void destroy(Waylib::Server::WServer *server) override;
diff --git a/src/seat/helper.cpp b/src/seat/helper.cpp
index e358fb1a96..ed41ece2fd 100644
--- a/src/seat/helper.cpp
+++ b/src/seat/helper.cpp
@@ -104,6 +104,9 @@
 
 #include <pwd.h>
 #include <utility>
+#include <linux/input.h>
+#include <sys/ioctl.h>
+#include <wayland-util.h>
 
 #define WLR_FRACTIONAL_SCALE_V1_VERSION 1
 #define EXT_DATA_CONTROL_MANAGER_V1_VERSION 1
@@ -2205,4 +2208,17 @@ void Helper::enableRender() {
 
 void Helper::disableRender() {
     m_renderWindow->setRenderEnabled(false);
+
+    // Revoke all evdev devices to prevent accidental events during switch
+    static const char prefix[] = "/dev/input/";
+    static const int prefixLen = strlen(prefix);
+    struct wlr_session *session = m_backend->session()->handle();
+    struct wlr_device *device = nullptr;
+    wl_list_for_each(device, &session->devices, link) {
+        char path[32];
+        if (readlink(qPrintable(QStringLiteral("/proc/self/fd/%1").arg(device->fd)), path, 32) < 0)
+            qCWarning(treelandCore) << "Failed to read path of file descriptor " << device->fd;
+        else if (strncmp(prefix, path, prefixLen))
+            ioctl(device->fd, EVIOCREVOKE, nullptr);
+    }
 }