ba9e364dab
Only wireguard-windows used this, and it's moving to wgnt exclusively. Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
99 lines
1.9 KiB
Go
99 lines
1.9 KiB
Go
/* SPDX-License-Identifier: MIT
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*
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* Copyright (C) 2017-2021 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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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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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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