98 lines
2.0 KiB
Go
98 lines
2.0 KiB
Go
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/* 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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"golang.org/x/sys/windows"
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"golang.zx2c4.com/wireguard/tun/wintun/memmod"
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"golang.zx2c4.com/wireguard/tun/wintun/resource"
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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 *memmod.Module
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}
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func newLazyDLL(name string) *lazyDLL {
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return &lazyDLL{Name: name}
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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 != nil {
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return nil
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}
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const ourModule windows.Handle = 0
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resInfo, err := resource.FindByName(ourModule, d.Name, resource.RT_RCDATA)
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if err != nil {
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return fmt.Errorf("Unable to find \"%v\" RCDATA resource: %v", d.Name, err)
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}
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data, err := resource.Load(ourModule, resInfo)
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if err != nil {
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return fmt.Errorf("Unable to load resource: %v", err)
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}
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module, err := memmod.LoadLibrary(data)
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if err != nil {
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return fmt.Errorf("Unable to load library: %v", err)
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}
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atomic.StorePointer((*unsafe.Pointer)(unsafe.Pointer(&d.module)), unsafe.Pointer(module))
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return nil
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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: %v", p.dll.Name, err)
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}
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addr, err := p.dll.module.ProcAddressByName(p.Name)
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if err != nil {
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return fmt.Errorf("Error getting %v address: %v", 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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