120 lines
2.1 KiB
Go
120 lines
2.1 KiB
Go
// Copyright 2010 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// +build darwin dragonfly freebsd linux netbsd openbsd
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// Unix environment variables.
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package syscall
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import "sync"
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var (
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// envOnce guards initialization by copyenv, which populates env.
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envOnce sync.Once
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// envLock guards env and envs.
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envLock sync.RWMutex
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// env maps from an environment variable to its first occurrence in envs.
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env map[string]int
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// envs is provided by the runtime. elements are expected to be
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// of the form "key=value".
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Envs []string
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)
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// setenv_c is provided by the runtime, but is a no-op if cgo isn't
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// loaded.
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func setenv_c(k, v string)
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func copyenv() {
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env = make(map[string]int)
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for i, s := range Envs {
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for j := 0; j < len(s); j++ {
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if s[j] == '=' {
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key := s[:j]
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if _, ok := env[key]; !ok {
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env[key] = i
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}
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break
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}
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}
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}
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}
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func Getenv(key string) (value string, found bool) {
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envOnce.Do(copyenv)
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if len(key) == 0 {
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return "", false
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}
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envLock.RLock()
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defer envLock.RUnlock()
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i, ok := env[key]
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if !ok {
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return "", false
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}
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s := Envs[i]
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for i := 0; i < len(s); i++ {
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if s[i] == '=' {
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return s[i+1:], true
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}
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}
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return "", false
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}
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func Setenv(key, value string) error {
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envOnce.Do(copyenv)
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if len(key) == 0 {
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return EINVAL
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}
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for i := 0; i < len(key); i++ {
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if key[i] == '=' || key[i] == 0 {
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return EINVAL
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}
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}
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for i := 0; i < len(value); i++ {
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if value[i] == 0 {
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return EINVAL
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}
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}
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envLock.Lock()
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defer envLock.Unlock()
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i, ok := env[key]
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kv := key + "=" + value
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if ok {
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Envs[i] = kv
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} else {
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i = len(Envs)
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Envs = append(Envs, kv)
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}
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env[key] = i
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setenv_c(key, value)
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return nil
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}
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func Clearenv() {
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envOnce.Do(copyenv) // prevent copyenv in Getenv/Setenv
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envLock.Lock()
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defer envLock.Unlock()
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env = make(map[string]int)
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Envs = []string{}
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// TODO(bradfitz): pass through to C
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}
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func Environ() []string {
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envOnce.Do(copyenv)
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envLock.RLock()
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defer envLock.RUnlock()
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a := make([]string, len(Envs))
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copy(a, Envs)
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return a
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}
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