Userland: Preserve keyboard mapping preference on reboot (#6955)

Userland/Services/KeyboardPreferenceLoader/main.cpp

@@ -0,0 +1,43 @@
+/*
+ * Copyright (c) 2021, the SerenityOS developers.
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <LibCore/ConfigFile.h>
+#include <spawn.h>
+#include <stdio.h>
+#include <unistd.h>
+
+int main()
+{
+    if (pledge("stdio proc exec rpath", nullptr) < 0) {
+        perror("pledge");
+        return 1;
+    }
+
+    if (unveil("/bin/keymap", "x") < 0) {
+        perror("unveil /bin/keymap");
+        return 1;
+    }
+
+    if (unveil("/etc/Keyboard.ini", "r") < 0) {
+        perror("unveil /etc/Keyboard.ini");
+        return 1;
+    }
+
+    if (unveil(nullptr, nullptr) < 0) {
+        perror("unveil");
+        return 1;
+    }
+
+    auto mapper_config(Core::ConfigFile::open("/etc/Keyboard.ini"));
+    auto keymap = mapper_config->read_entry("Mapping", "Keymap", "");
+
+    pid_t child_pid;
+    const char* argv[] = { "/bin/keymap", keymap.characters(), nullptr };
+    if ((errno = posix_spawn(&child_pid, "/bin/keymap", nullptr, nullptr, const_cast<char**>(argv), environ))) {
+        perror("posix_spawn");
+        exit(1);
+    }
+}