Add option to only grab virtual devices, to support input remapping software

tools/gsr-global-hotkeys/keyboard_event.c

@@ -213,11 +213,41 @@ static bool keyboard_event_has_event_with_dev_input_fd(keyboard_event *self, int
     return false;
 }
 
+/* TODO: Is there a more efficient way to do this? */
+static bool dev_input_is_virtual(int dev_input_id) {
+    DIR *dir = opendir("/sys/devices/virtual/input");
+    if(!dir)
+        return false;
+
+    bool is_virtual = false;
+    char virtual_input_filepath[1024];
+    for(;;) {
+        struct dirent *entry = readdir(dir);
+        if(!entry)
+            break;
+
+        if(strncmp(entry->d_name, "input", 5) != 0)
+            continue;
+
+        snprintf(virtual_input_filepath, sizeof(virtual_input_filepath), "/sys/devices/virtual/input/%s/event%d", entry->d_name, dev_input_id);
+        if(access(virtual_input_filepath, F_OK) == 0) {
+            is_virtual = true;
+            break;
+        }
+    }
+
+    closedir(dir);
+    return is_virtual;
+}
+
 static bool keyboard_event_try_add_device_if_keyboard(keyboard_event *self, const char *dev_input_filepath) {
     const int dev_input_id = get_dev_input_id_from_filepath(dev_input_filepath);
     if(dev_input_id == -1)
         return false;
 
+    if(self->grab_type == KEYBOARD_GRAB_TYPE_VIRTUAL && !dev_input_is_virtual(dev_input_id))
+        return false;
+
     if(keyboard_event_has_event_with_dev_input_fd(self, dev_input_id))
         return false;
 
@@ -373,10 +403,11 @@ static int setup_virtual_keyboard_input(const char *name) {
     return fd;
 }
 
-bool keyboard_event_init(keyboard_event *self, bool poll_stdout_error, bool exclusive_grab) {
+bool keyboard_event_init(keyboard_event *self, bool poll_stdout_error, bool exclusive_grab, keyboard_grab_type grab_type) {
     memset(self, 0, sizeof(*self));
     self->stdout_event_index = -1;
     self->hotplug_event_index = -1;
+    self->grab_type = grab_type;
 
     if(exclusive_grab) {
         self->uinput_fd = setup_virtual_keyboard_input(GSR_UI_VIRTUAL_KEYBOARD_NAME);

tools/gsr-global-hotkeys/keyboard_event.h

@@ -36,6 +36,11 @@ typedef struct {
     int num_keys_pressed;
 } event_extra_data;
 
+typedef enum {
+    KEYBOARD_GRAB_TYPE_ALL,
+    KEYBOARD_GRAB_TYPE_VIRTUAL
+} keyboard_grab_type;
+
 typedef struct {
     struct pollfd event_polls[MAX_EVENT_POLLS];      /* Current size is |num_event_polls| */
     event_extra_data event_extra_data[MAX_EVENT_POLLS]; /* Current size is |num_event_polls| */
@@ -45,6 +50,7 @@ typedef struct {
     int hotplug_event_index;
     int uinput_fd;
     bool stdout_failed;
+    keyboard_grab_type grab_type;
 
     hotplug_event hotplug_ev;
 
@@ -62,7 +68,7 @@ typedef struct {
 /* Return true to allow other applications to receive the key input (when using exclusive grab) */
 typedef bool (*key_callback)(uint32_t key, uint32_t modifiers, int press_status, void *userdata);
 
-bool keyboard_event_init(keyboard_event *self, bool poll_stdout_error, bool exclusive_grab);
+bool keyboard_event_init(keyboard_event *self, bool poll_stdout_error, bool exclusive_grab, keyboard_grab_type grab_type);
 void keyboard_event_deinit(keyboard_event *self);
 
 /* If |timeout_milliseconds| is -1 then wait until an event is received */

tools/gsr-global-hotkeys/main.c

@@ -3,6 +3,7 @@
 /* C stdlib */
 #include <stdio.h>
 #include <stdint.h>
+#include <string.h>
 
 /* POSIX */
 #include <unistd.h>
@@ -37,7 +38,32 @@ static bool on_key_callback(uint32_t key, uint32_t modifiers, int press_status,
     return true;
 }
 
-int main(void) {
+static void usage(void) {
+    fprintf(stderr, "usage: gsr-global-hotkeys [--all|--virtual]\n");
+    fprintf(stderr, "OPTIONS:\n");
+    fprintf(stderr, "  --all        Grab all devices.\n");
+    fprintf(stderr, "  --virtual    Grab all virtual devices only.\n");
+}
+
+int main(int argc, char **argv) {
+    keyboard_grab_type grab_type = KEYBOARD_GRAB_TYPE_ALL;
+    if(argc == 2) {
+        const char *grab_type_arg = argv[1];
+        if(strcmp(grab_type_arg, "--all") == 0) {
+            grab_type = KEYBOARD_GRAB_TYPE_ALL;
+        } else if(strcmp(grab_type_arg, "--virtual") == 0) {
+            grab_type = KEYBOARD_GRAB_TYPE_VIRTUAL;
+        } else {
+            fprintf(stderr, "Error: expected --all or --virtual, got %s\n", grab_type_arg);
+            usage();
+            return 1;
+        }
+    } else if(argc != 1) {
+        fprintf(stderr, "Error: expected 0 or 1 arguments, got %d argument(s)\n", argc);
+        usage();
+        return 1;
+    }
+
     const uid_t user_id = getuid();
     if(geteuid() != 0) {
         if(setuid(0) == -1) {
@@ -47,7 +73,7 @@ int main(void) {
     }
 
     keyboard_event keyboard_ev;
-    if(!keyboard_event_init(&keyboard_ev, true, true)) {
+    if(!keyboard_event_init(&keyboard_ev, true, true, grab_type)) {
         fprintf(stderr, "Error: failed to setup hotplugging and no keyboard input devices were found\n");
         setuid(user_id);
         return 1;