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>
60 lines
1.1 KiB
Go
60 lines
1.1 KiB
Go
/* SPDX-License-Identifier: MIT
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*
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* Copyright (C) 2020 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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)
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func newLazyDLL(name string, onLoad func(d *lazyDLL)) *lazyDLL {
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return &lazyDLL{Name: name, onLoad: onLoad}
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}
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func (d *lazyDLL) NewProc(name string) *lazyProc {
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return &lazyProc{dll: d, Name: name}
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}
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type lazyProc struct {
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Name string
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mu sync.Mutex
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dll *lazyDLL
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addr uintptr
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}
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func (p *lazyProc) Find() error {
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if atomic.LoadPointer((*unsafe.Pointer)(unsafe.Pointer(&p.addr))) != nil {
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return nil
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}
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p.mu.Lock()
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defer p.mu.Unlock()
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if p.addr != 0 {
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return nil
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}
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err := p.dll.Load()
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if err != nil {
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return fmt.Errorf("Error loading %v DLL: %w", p.dll.Name, err)
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}
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addr, err := p.nameToAddr()
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if err != nil {
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return fmt.Errorf("Error getting %v address: %w", p.Name, err)
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}
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atomic.StorePointer((*unsafe.Pointer)(unsafe.Pointer(&p.addr)), unsafe.Pointer(addr))
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return nil
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}
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func (p *lazyProc) Addr() uintptr {
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err := p.Find()
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if err != nil {
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panic(err)
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}
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return p.addr
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}
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