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comparison libgo/go/internal/syscall/execenv/execenv_windows.go @ 152:2b5abeee2509

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update gcc11
author anatofuz
date Mon, 25 May 2020 07:50:57 +0900
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145:1830386684a0 152:2b5abeee2509
1 // Copyright 2020 The Go Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style
3 // license that can be found in the LICENSE file.
4
5 // +build windows
6
7 package execenv
8
9 import (
10 "internal/syscall/windows"
11 "syscall"
12 "unicode/utf16"
13 "unsafe"
14 )
15
16 // Default will return the default environment
17 // variables based on the process attributes
18 // provided.
19 //
20 // If the process attributes contain a token, then
21 // the environment variables will be sourced from
22 // the defaults for that user token, otherwise they
23 // will be sourced from syscall.Environ().
24 func Default(sys *syscall.SysProcAttr) (env []string, err error) {
25 if sys == nil || sys.Token == 0 {
26 return syscall.Environ(), nil
27 }
28 var block *uint16
29 err = windows.CreateEnvironmentBlock(&block, sys.Token, false)
30 if err != nil {
31 return nil, err
32 }
33 defer windows.DestroyEnvironmentBlock(block)
34 blockp := uintptr(unsafe.Pointer(block))
35 for {
36
37 // find NUL terminator
38 end := unsafe.Pointer(blockp)
39 for *(*uint16)(end) != 0 {
40 end = unsafe.Pointer(uintptr(end) + 2)
41 }
42
43 n := (uintptr(end) - uintptr(unsafe.Pointer(blockp))) / 2
44 if n == 0 {
45 // environment block ends with empty string
46 break
47 }
48
49 entry := (*[(1 << 30) - 1]uint16)(unsafe.Pointer(blockp))[:n:n]
50 env = append(env, string(utf16.Decode(entry)))
51 blockp += 2 * (uintptr(len(entry)) + 1)
52 }
53 return
54 }