| // Copyright 2010 The Go Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style |
| // license that can be found in the LICENSE file. |
| |
| // Windows environment variables. |
| |
| package syscall |
| |
| import ( |
| "unicode/utf16" |
| "unsafe" |
| ) |
| |
| func Getenv(key string) (value string, found bool) { |
| keyp, err := UTF16PtrFromString(key) |
| if err != nil { |
| return "", false |
| } |
| n := uint32(100) |
| for { |
| b := make([]uint16, n) |
| n, err = GetEnvironmentVariable(keyp, &b[0], uint32(len(b))) |
| if n == 0 && err == ERROR_ENVVAR_NOT_FOUND { |
| return "", false |
| } |
| if n <= uint32(len(b)) { |
| return string(utf16.Decode(b[:n])), true |
| } |
| } |
| } |
| |
| func Setenv(key, value string) error { |
| v, err := UTF16PtrFromString(value) |
| if err != nil { |
| return err |
| } |
| keyp, err := UTF16PtrFromString(key) |
| if err != nil { |
| return err |
| } |
| e := SetEnvironmentVariable(keyp, v) |
| if e != nil { |
| return e |
| } |
| runtimeSetenv(key, value) |
| return nil |
| } |
| |
| func Unsetenv(key string) error { |
| keyp, err := UTF16PtrFromString(key) |
| if err != nil { |
| return err |
| } |
| e := SetEnvironmentVariable(keyp, nil) |
| if e != nil { |
| return e |
| } |
| runtimeUnsetenv(key) |
| return nil |
| } |
| |
| func Clearenv() { |
| for _, s := range Environ() { |
| // Environment variables can begin with = |
| // so start looking for the separator = at j=1. |
| // https://blogs.msdn.com/b/oldnewthing/archive/2010/05/06/10008132.aspx |
| for j := 1; j < len(s); j++ { |
| if s[j] == '=' { |
| Unsetenv(s[0:j]) |
| break |
| } |
| } |
| } |
| } |
| |
| func Environ() []string { |
| envp, e := GetEnvironmentStrings() |
| if e != nil { |
| return nil |
| } |
| defer FreeEnvironmentStrings(envp) |
| |
| r := make([]string, 0, 50) // Empty with room to grow. |
| const size = unsafe.Sizeof(*envp) |
| for *envp != 0 { // environment block ends with empty string |
| // find NUL terminator |
| end := unsafe.Pointer(envp) |
| for *(*uint16)(end) != 0 { |
| end = unsafe.Add(end, size) |
| } |
| |
| entry := unsafe.Slice(envp, (uintptr(end)-uintptr(unsafe.Pointer(envp)))/size) |
| r = append(r, string(utf16.Decode(entry))) |
| envp = (*uint16)(unsafe.Add(end, size)) |
| } |
| return r |
| } |