ca9edf1c63
This prevents linking to wintun.dll until it's actually needed, which should improve startup time. Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
55 lines
1.1 KiB
Go
55 lines
1.1 KiB
Go
// +build !load_wintun_from_rsrc
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/* SPDX-License-Identifier: MIT
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*
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* Copyright (C) 2019 WireGuard LLC. All Rights Reserved.
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*/
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package wintun
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import (
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"fmt"
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"sync"
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"sync/atomic"
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"unsafe"
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"golang.org/x/sys/windows"
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)
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type lazyDLL struct {
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Name string
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mu sync.Mutex
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module windows.Handle
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onLoad func(d *lazyDLL)
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}
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func (d *lazyDLL) Load() error {
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if atomic.LoadPointer((*unsafe.Pointer)(unsafe.Pointer(&d.module))) != nil {
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return nil
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}
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d.mu.Lock()
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defer d.mu.Unlock()
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if d.module != 0 {
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return nil
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}
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const (
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LOAD_LIBRARY_SEARCH_APPLICATION_DIR = 0x00000200
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LOAD_LIBRARY_SEARCH_SYSTEM32 = 0x00000800
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)
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module, err := windows.LoadLibraryEx(d.Name, 0, LOAD_LIBRARY_SEARCH_APPLICATION_DIR|LOAD_LIBRARY_SEARCH_SYSTEM32)
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if err != nil {
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return fmt.Errorf("Unable to load library: %w", err)
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}
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atomic.StorePointer((*unsafe.Pointer)(unsafe.Pointer(&d.module)), unsafe.Pointer(module))
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if d.onLoad != nil {
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d.onLoad(d)
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}
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return nil
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}
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func (p *lazyProc) nameToAddr() (uintptr, error) {
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return windows.GetProcAddress(p.dll.module, p.Name)
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}
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