1 files changed, 62 insertions, 0 deletions
diff --git a/driver/dll_fromrsrc_windows.go b/driver/dll_fromrsrc_windows.go
new file mode 100644
index 00000000..65b1cfce
--- /dev/null
+++ b/driver/dll_fromrsrc_windows.go
@@ -0,0 +1,62 @@
+//go:build load_wgnt_from_rsrc
+
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2019 WireGuard LLC. All Rights Reserved.
+ */
+
+package driver
+
+import (
+	"fmt"
+	"sync"
+	"sync/atomic"
+	"unsafe"
+
+	"golang.org/x/sys/windows"
+	"golang.zx2c4.com/wireguard/windows/driver/memmod"
+)
+
+type lazyDLL struct {
+	Name   string
+	Base   windows.Handle
+	mu     sync.Mutex
+	module *memmod.Module
+	onLoad func(d *lazyDLL)
+}
+
+func (d *lazyDLL) Load() error {
+	if atomic.LoadPointer((*unsafe.Pointer)(unsafe.Pointer(&d.module))) != nil {
+		return nil
+	}
+	d.mu.Lock()
+	defer d.mu.Unlock()
+	if d.module != nil {
+		return nil
+	}
+
+	const ourModule windows.Handle = 0
+	resInfo, err := windows.FindResource(ourModule, d.Name, windows.RT_RCDATA)
+	if err != nil {
+		return fmt.Errorf("Unable to find \"%v\" RCDATA resource: %w", d.Name, err)
+	}
+	data, err := windows.LoadResourceData(ourModule, resInfo)
+	if err != nil {
+		return fmt.Errorf("Unable to load resource: %w", err)
+	}
+	module, err := memmod.LoadLibrary(data)
+	if err != nil {
+		return fmt.Errorf("Unable to load library: %w", err)
+	}
+	d.Base = windows.Handle(module.BaseAddr())
+
+	atomic.StorePointer((*unsafe.Pointer)(unsafe.Pointer(&d.module)), unsafe.Pointer(module))
+	if d.onLoad != nil {
+		d.onLoad(d)
+	}
+	return nil
+}
+
+func (p *lazyProc) nameToAddr() (uintptr, error) {
+	return p.dll.module.ProcAddressByName(p.Name)
+}