rename to fortify and restructure

More sandbox features will be added and this will no longer track ego's features and behaviour.

Signed-off-by: Ophestra Umiker <cat@ophivana.moe>

internal/util/simple.go

@@ -0,0 +1,39 @@
+package util
+
+import (
+	"io"
+	"os"
+	"os/exec"
+)
+
+func Which(file string) (string, bool) {
+	p, err := exec.LookPath(file)
+	return p, err == nil
+}
+
+func CopyFile(dst, src string) error {
+	srcD, err := os.Open(src)
+	if err != nil {
+		return err
+	}
+	defer func() {
+		if srcD.Close() != nil {
+			// unreachable
+			panic("src file closed prematurely")
+		}
+	}()
+
+	dstD, err := os.OpenFile(dst, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0600)
+	if err != nil {
+		return err
+	}
+	defer func() {
+		if dstD.Close() != nil {
+			// unreachable
+			panic("dst file closed prematurely")
+		}
+	}()
+
+	_, err = io.Copy(dstD, srcD)
+	return err
+}