Add tuxedo-touchpad-toggle executable

When executed, tuxedo-touchpad-toggle toggles the enabled/disabled state
of the touchpad. This executable makes it easy to bind the toggle to any
key combination so one can toggle the touchpad in any desktop
environment.

CMakeLists.txt

@@ -30,7 +30,11 @@ pkg_check_modules(deps REQUIRED IMPORTED_TARGET gio-2.0 udev)
 add_executable(tuxedo-touchpad-switch tuxedo-touchpad-switch.cpp setup-gnome.cpp setup-kde.cpp touchpad-control.cpp)
 target_link_libraries(tuxedo-touchpad-switch udev PkgConfig::deps)
 
+add_executable(tuxedo-touchpad-toggle tuxedo-touchpad-toggle.cpp touchpad-control.cpp)
+target_link_libraries(tuxedo-touchpad-toggle udev PkgConfig::deps)
+
 install(TARGETS tuxedo-touchpad-switch DESTINATION bin/)
+install(TARGETS tuxedo-touchpad-toggle DESTINATION bin/)
 install(FILES res/99-tuxedo-touchpad-switch.rules DESTINATION lib/udev/rules.d/)
 install(FILES res/tuxedo-touchpad-switch-lockfile DESTINATION /etc/ PERMISSIONS OWNER_READ GROUP_READ WORLD_READ) # absolute path on purpose: implemented as such in tuxedo-touchpad-switch.cpp
 install(FILES res/tuxedo-touchpad-switch.desktop DESTINATION /usr/share/gdm/greeter/autostart/) # absolute path on purpose: gdm has no config dir in /usr/local/

touchpad-control.cpp

@@ -144,3 +144,48 @@ int set_touchpad_state(int enabled) {
     
     return result;
 }
+
+int toggle_touchpad_state() {
+    std::vector<std::string> devnodes;
+    int touchpad_count = get_touchpad_hidraw_devices(&devnodes);
+    if (touchpad_count < 0) {
+        cerr << "get_touchpad_hidraw_devices failed." << endl;
+        return EXIT_FAILURE;
+    }
+    if (touchpad_count == 0) {
+        cout << "No compatible touchpads found." << endl;
+        return EXIT_FAILURE;
+    }
+
+    int result = EXIT_SUCCESS;
+
+    for (auto it = devnodes.begin(); it != devnodes.end(); ++it) {
+        int hidraw = open((*it).c_str(), O_WRONLY|O_NONBLOCK);
+        if (hidraw < 0) {
+            cerr << "open(\"" << *it << "\", O_WRONLY|O_NONBLOCK) failed." << endl;
+            result = EXIT_FAILURE;
+        }
+        else {
+            // get the device's state first (feature report nr.7 - 0x07)
+            char buffer[2] = {0x07, 0x00};
+            ioctl(hidraw, HIDIOCGFEATURE(2), buffer);
+
+            // toggle the state
+            if (buffer[1] == 0x00) {
+                buffer[1] = 0x03; // enable touchpad
+            } else {
+                buffer[1] = 0x00; // disable touchpad
+            }
+
+            int result = ioctl(hidraw, HIDIOCSFEATURE(2), buffer);
+            if (result < 0) {
+                cerr << "ioctl on " << *it << " failed." << endl;
+                result = EXIT_FAILURE;
+            }
+
+            close(hidraw);
+        }
+    }
+
+    return result;
+}

touchpad-control.h

@@ -20,3 +20,5 @@
 // "int enable" set to 0 disables the touchpad, any other value enables it
 // returns EXIT_SUCCESS or EXIT_FAILURE accordingly, on fail the activate/deactivate state of found touchpads is undefined
 int set_touchpad_state(int enabled);
+
+int toggle_touchpad_state();

tuxedo-touchpad-toggle.cpp

@@ -0,0 +1,5 @@
+#include "touchpad-control.h"
+
+int main() {
+    return toggle_touchpad_state();
+}