SystemDialog: Add a new app for showing system dialogs.

Currently this will be used by the WindowServer to show some dialogs.
This is needed since WindowServer can't use LibGUI and reimplementing
message box functionality inside WindowServer would be silly. :^)

The only dialog supported in this initial version is --shutdown

Applications/SystemDialog/Makefile

@@ -0,0 +1,8 @@
+include ../../Makefile.common
+
+OBJS = \
+    main.o
+
+APP = SystemDialog
+
+include ../Makefile.common

Applications/SystemDialog/main.cpp

@@ -0,0 +1,49 @@
+#include <LibGUI/GApplication.h>
+#include <LibGUI/GBoxLayout.h>
+#include <LibGUI/GButton.h>
+#include <LibGUI/GDesktop.h>
+#include <LibGUI/GLabel.h>
+#include <LibGUI/GMessageBox.h>
+#include <LibGUI/GWindow.h>
+#include <stdio.h>
+#include <sys/utsname.h>
+
+static int run_shutdown_dialog(int argc, char** argv);
+
+int main(int argc, char** argv)
+{
+    if (argc != 2) {
+        printf("usage: SystemDialog <type>\n");
+        return 0;
+    }
+
+    if (String(argv[1]) == "--shutdown")
+        return run_shutdown_dialog(argc, argv);
+
+    fprintf(stderr, "Unknown argument: %s\n", argv[1]);
+    return 1;
+}
+
+int run_shutdown_dialog(int argc, char** argv)
+{
+    GApplication app(argc, argv);
+
+    {
+        GMessageBox box("Shut down Serenity?", "Confirm Shutdown", GMessageBox::Type::Warning, GMessageBox::InputType::OkCancel);
+        auto result = box.exec();
+
+        if (result == GMessageBox::ExecOK) {
+            dbg() << "OK";
+            int rc = execl("/bin/shutdown", "/bin/shutdown", "-n", nullptr);
+            if (rc < 0) {
+                perror("execl");
+                return 1;
+            }
+        } else {
+            dbg() << "Cancel";
+            return 0;
+        }
+    }
+
+    return app.exec();
+}

Kernel/build-root-filesystem.sh

@@ -78,6 +78,7 @@ cp ../Applications/TextEditor/TextEditor mnt/bin/TextEditor
 cp ../Applications/PaintBrush/PaintBrush mnt/bin/PaintBrush
 cp ../Applications/QuickShow/QuickShow mnt/bin/QuickShow
 cp ../Applications/Piano/Piano mnt/bin/Piano
+cp ../Applications/SystemDialog/SystemDialog mnt/bin/SystemDialog
 cp ../Demos/HelloWorld/HelloWorld mnt/bin/HelloWorld
 cp ../Demos/HelloWorld2/HelloWorld2 mnt/bin/HelloWorld2
 cp ../Demos/RetroFetch/RetroFetch mnt/bin/RetroFetch
@@ -110,6 +111,7 @@ ln -s TextEditor mnt/bin/te
 ln -s PaintBrush mnt/bin/pb
 ln -s QuickShow mnt/bin/qs
 ln -s Piano mnt/bin/pi
+ln -s SystemDialog mnt/bin/sd
 echo "done"
 
 # Run local sync script, if it exists

Kernel/makeall.sh

@@ -39,6 +39,7 @@ build_targets="$build_targets ../Applications/Downloader"
 build_targets="$build_targets ../Applications/PaintBrush"
 build_targets="$build_targets ../Applications/QuickShow"
 build_targets="$build_targets ../Applications/Piano"
+build_targets="$build_targets ../Applications/SystemDialog"
 build_targets="$build_targets ../DevTools/VisualBuilder"
 build_targets="$build_targets ../Games/Minesweeper"
 build_targets="$build_targets ../Games/Snake"