apps: Add ln

apps/CMakeLists.txt

@@ -28,3 +28,4 @@ luna_app(mount.cpp mount)
 luna_app(umount.cpp umount)
 luna_app(ps.cpp ps)
 luna_app(time.cpp time)
+luna_app(ln.cpp ln)

apps/ln.cpp

@@ -0,0 +1,24 @@
+#include <os/ArgumentParser.h>
+#include <stdio.h>
+#include <unistd.h>
+
+Result<int> luna_main(int argc, char** argv)
+{
+    StringView target;
+    StringView link;
+
+    os::ArgumentParser parser;
+    parser.add_description("Create symbolic links.");
+    parser.add_system_program_info("ln"_sv);
+    parser.add_positional_argument(target, "target", true);
+    parser.add_positional_argument(link, "linkpath", true);
+    parser.parse(argc, argv);
+
+    if (symlink(target.chars(), link.chars()) < 0)
+    {
+        perror("ln");
+        return 1;
+    }
+
+    return 0;
+}