Fix leds getting unset when closing the program

tools/gsr-global-hotkeys/keyboard_event.c

@@ -1,5 +1,6 @@
 #include "keyboard_event.h"
 #include "keys.h"
+#include "leds.h"
 
 /* C stdlib */
 #include <stdio.h>
@@ -716,6 +717,41 @@ bool keyboard_event_init(keyboard_event *self, bool exclusive_grab, keyboard_gra
     return true;
 }
 
+static void write_led_data_to_device(int fd, uint16_t led, int value) {
+    struct input_event led_data = {
+        .type = EV_LED,
+        .code = led,
+        .value = value
+    };
+    write(fd, &led_data, sizeof(led_data));
+
+    struct input_event syn_data = {
+        .type = EV_SYN,
+        .code = 0,
+        .value = 0
+    };
+    write(fd, &syn_data, sizeof(syn_data));
+}
+
+/* When the device is ungrabbed the leds are unset for some reason. Set them back to their previous brightness */
+static void keyboard_event_device_deinit(int fd, event_extra_data *extra_data) {
+    ggh_leds leds;
+    const bool got_leds = get_leds(extra_data->dev_input_id, &leds);
+
+    ioctl(fd, EVIOCGRAB, 0);
+    if(got_leds) {
+        if(leds.scroll_lock_brightness >= 0)
+            write_led_data_to_device(fd, LED_SCROLLL, leds.scroll_lock_brightness);
+
+        if(leds.num_lock_brightness >= 0)
+            write_led_data_to_device(fd, LED_NUML, leds.num_lock_brightness);
+
+        if(leds.caps_lock_brightness >= 0)
+            write_led_data_to_device(fd, LED_CAPSL, leds.caps_lock_brightness);
+    }
+    close(fd);
+}
+
 void keyboard_event_deinit(keyboard_event *self) {
     self->running = false;
 
@@ -732,8 +768,10 @@ void keyboard_event_deinit(keyboard_event *self) {
 
     for(int i = 0; i < self->num_event_polls; ++i) {
         if(self->event_polls[i].fd > 0) {
-            ioctl(self->event_polls[i].fd, EVIOCGRAB, 0);
-            close(self->event_polls[i].fd);
+            if(self->event_extra_data[i].dev_input_id > 0 && !self->event_extra_data[i].gsr_ui_virtual_keyboard)
+                keyboard_event_device_deinit(self->event_polls[i].fd, &self->event_extra_data[i]);
+            else
+                close(self->event_polls[i].fd);
         }
         free(self->event_extra_data[i].key_states);
         free(self->event_extra_data[i].key_presses_grabbed);

tools/gsr-global-hotkeys/leds.c

@@ -15,27 +15,37 @@
 /* LINUX */
 #include <linux/input.h>
 
-static int get_max_brightness(const char *sys_class_path, const char *filename) {
-    char path[PATH_MAX];
-    snprintf(path, sizeof(path), "%s/%s/max_brightness", sys_class_path, filename);
-
-    const int fd = open(path, O_RDONLY);
+/* Returns -1 on error */
+static int read_int_from_file(const char *filepath) {
+    const int fd = open(filepath, O_RDONLY);
     if(fd == -1) {
         fprintf(stderr, "Warning: get_max_brightness open error: %s\n", strerror(errno));
-        return false;
+        return -1;
     }
 
     bool success = false;
-    int max_brightness = 0;
+    int value = 0;
     char buffer[32];
     const ssize_t num_bytes_read = read(fd, buffer, sizeof(buffer));
     if(num_bytes_read > 0) {
         buffer[num_bytes_read] = '\0';
-        success = sscanf(buffer, "%d", &max_brightness) == 1;
+        success = sscanf(buffer, "%d", &value) == 1;
     }
 
     close(fd);
-    return success;
+    return success ? value : -1;
+}
+
+static int get_max_brightness(const char *sys_class_path, const char *filename) {
+    char path[PATH_MAX];
+    snprintf(path, sizeof(path), "%s/%s/max_brightness", sys_class_path, filename);
+    return read_int_from_file(path);
+}
+
+static int get_brightness(const char *sys_class_path, const char *filename) {
+    char path[PATH_MAX];
+    snprintf(path, sizeof(path), "%s/%s/brightness", sys_class_path, filename);
+    return read_int_from_file(path);
 }
 
 static bool string_starts_with(const char *str, const char *sub) {
@@ -137,3 +147,35 @@ bool set_leds(const char *led_name, bool enabled) {
         return false;
     }
 }
+
+bool get_leds(int event_number, ggh_leds *leds) {
+    leds->scroll_lock_brightness = -1;
+    leds->num_lock_brightness = -1;
+    leds->caps_lock_brightness = -1;
+
+    char path[PATH_MAX];
+    snprintf(path, sizeof(path), "/sys/class/input/event%d/device", event_number);
+
+    DIR *dir = opendir(path);
+    if(!dir)
+        return false;
+
+    struct dirent *entry;
+    while((entry = readdir(dir)) != NULL) {
+        if(entry->d_name[0] == '.')
+            continue;
+
+        if(!string_starts_with(entry->d_name, "input"))
+            continue;
+
+        if(string_ends_with(entry->d_name, "::scrolllock"))
+            leds->scroll_lock_brightness = get_brightness(path, entry->d_name);
+        else if(string_ends_with(entry->d_name, "::numlock"))
+            leds->num_lock_brightness = get_brightness(path, entry->d_name);
+        else if(string_ends_with(entry->d_name, "::capslock"))
+            leds->caps_lock_brightness = get_brightness(path, entry->d_name);
+    }
+
+    closedir(dir);
+    return true;
+}

tools/gsr-global-hotkeys/leds.h

@@ -4,6 +4,14 @@
 /* C stdlib */
 #include <stdbool.h>
 
+typedef struct {
+    /* These are set to -1 if not supported */
+    int scroll_lock_brightness;
+    int num_lock_brightness;
+    int caps_lock_brightness;
+} ggh_leds;
+
 bool set_leds(const char *led_name, bool enabled);
+bool get_leds(int event_number, ggh_leds *leds);
 
 #endif /* LEDS_H */